root/net/ipv6/addrconf.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      IPv6 Address [auto]configuration
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
 */

/*
 *      Changes:
 *
 *      Janos Farkas                    :       delete timer on ifdown
 *      <chexum@bankinf.banki.hu>
 *      Andi Kleen                      :       kill double kfree on module
 *                                              unload.
 *      Maciej W. Rozycki               :       FDDI support
 *      sekiya@USAGI                    :       Don't send too many RS
 *                                              packets.
 *      yoshfuji@USAGI                  :       Fixed interval between DAD
 *                                              packets.
 *      YOSHIFUJI Hideaki @USAGI        :       improved accuracy of
 *                                              address validation timer.
 *      YOSHIFUJI Hideaki @USAGI        :       Privacy Extensions (RFC3041)
 *                                              support.
 *      Yuji SEKIYA @USAGI              :       Don't assign a same IPv6
 *                                              address on a same interface.
 *      YOSHIFUJI Hideaki @USAGI        :       ARCnet support
 *      YOSHIFUJI Hideaki @USAGI        :       convert /proc/net/if_inet6 to
 *                                              seq_file.
 *      YOSHIFUJI Hideaki @USAGI        :       improved source address
 *                                              selection; consider scope,
 *                                              status etc.
 */

#define pr_fmt(fmt) "IPv6: " fmt

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_addr.h>
#include <linux/if_arp.h>
#include <linux/if_arcnet.h>
#include <linux/if_infiniband.h>
#include <linux/route.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/slab.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/string.h>
#include <linux/hash.h>

#include <net/ip_tunnels.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/snmp.h>

#include <net/6lowpan.h>
#include <net/firewire.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/tcp.h>
#include <net/ip.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/l3mdev.h>
#include <net/netdev_lock.h>
#include <linux/if_tunnel.h>
#include <linux/rtnetlink.h>
#include <linux/netconf.h>
#include <linux/random.h>
#include <linux/uaccess.h>
#include <linux/unaligned.h>

#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/export.h>
#include <linux/ioam6.h>

#define IPV6_MAX_STRLEN \
        sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")

static inline u32 cstamp_delta(unsigned long cstamp)
{
        return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
}

static inline s32 rfc3315_s14_backoff_init(s32 irt)
{
        /* multiply 'initial retransmission time' by 0.9 .. 1.1 */
        u64 tmp = get_random_u32_inclusive(900000, 1100000) * (u64)irt;
        do_div(tmp, 1000000);
        return (s32)tmp;
}

static inline s32 rfc3315_s14_backoff_update(s32 rt, s32 mrt)
{
        /* multiply 'retransmission timeout' by 1.9 .. 2.1 */
        u64 tmp = get_random_u32_inclusive(1900000, 2100000) * (u64)rt;
        do_div(tmp, 1000000);
        if ((s32)tmp > mrt) {
                /* multiply 'maximum retransmission time' by 0.9 .. 1.1 */
                tmp = get_random_u32_inclusive(900000, 1100000) * (u64)mrt;
                do_div(tmp, 1000000);
        }
        return (s32)tmp;
}

#ifdef CONFIG_SYSCTL
static int addrconf_sysctl_register(struct inet6_dev *idev);
static void addrconf_sysctl_unregister(struct inet6_dev *idev);
#else
static inline int addrconf_sysctl_register(struct inet6_dev *idev)
{
        return 0;
}

static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
{
}
#endif

static void ipv6_gen_rnd_iid(struct in6_addr *addr);

static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
static int ipv6_count_addresses(const struct inet6_dev *idev);
static int ipv6_generate_stable_address(struct in6_addr *addr,
                                        u8 dad_count,
                                        const struct inet6_dev *idev);

#define IN6_ADDR_HSIZE_SHIFT    8
#define IN6_ADDR_HSIZE          (1 << IN6_ADDR_HSIZE_SHIFT)

static void addrconf_verify(struct net *net);
static void addrconf_verify_rtnl(struct net *net);

static struct workqueue_struct *addrconf_wq;

static void addrconf_join_anycast(struct inet6_ifaddr *ifp);
static void addrconf_leave_anycast(struct inet6_ifaddr *ifp);

static void addrconf_type_change(struct net_device *dev,
                                 unsigned long event);
static int addrconf_ifdown(struct net_device *dev, bool unregister);

static struct fib6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
                                                  int plen,
                                                  const struct net_device *dev,
                                                  u32 flags, u32 noflags,
                                                  bool no_gw);

static void addrconf_dad_start(struct inet6_ifaddr *ifp);
static void addrconf_dad_work(struct work_struct *w);
static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
                                   bool send_na);
static void addrconf_dad_run(struct inet6_dev *idev, bool restart);
static void addrconf_rs_timer(struct timer_list *t);
static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);
static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);

static void inet6_prefix_notify(int event, struct inet6_dev *idev,
                                struct prefix_info *pinfo);

static struct ipv6_devconf ipv6_devconf __read_mostly = {
        .forwarding             = 0,
        .hop_limit              = IPV6_DEFAULT_HOPLIMIT,
        .mtu6                   = IPV6_MIN_MTU,
        .accept_ra              = 1,
        .accept_redirects       = 1,
        .autoconf               = 1,
        .force_mld_version      = 0,
        .mldv1_unsolicited_report_interval = 10 * HZ,
        .mldv2_unsolicited_report_interval = HZ,
        .dad_transmits          = 1,
        .rtr_solicits           = MAX_RTR_SOLICITATIONS,
        .rtr_solicit_interval   = RTR_SOLICITATION_INTERVAL,
        .rtr_solicit_max_interval = RTR_SOLICITATION_MAX_INTERVAL,
        .rtr_solicit_delay      = MAX_RTR_SOLICITATION_DELAY,
        .use_tempaddr           = 0,
        .temp_valid_lft         = TEMP_VALID_LIFETIME,
        .temp_prefered_lft      = TEMP_PREFERRED_LIFETIME,
        .regen_min_advance      = REGEN_MIN_ADVANCE,
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
        .max_addresses          = IPV6_MAX_ADDRESSES,
        .accept_ra_defrtr       = 1,
        .ra_defrtr_metric       = IP6_RT_PRIO_USER,
        .accept_ra_from_local   = 0,
        .accept_ra_min_hop_limit= 1,
        .accept_ra_min_lft      = 0,
        .accept_ra_pinfo        = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
        .accept_ra_rtr_pref     = 1,
        .rtr_probe_interval     = 60 * HZ,
#ifdef CONFIG_IPV6_ROUTE_INFO
        .accept_ra_rt_info_min_plen = 0,
        .accept_ra_rt_info_max_plen = 0,
#endif
#endif
        .proxy_ndp              = 0,
        .accept_source_route    = 0,    /* we do not accept RH0 by default. */
        .disable_ipv6           = 0,
        .accept_dad             = 0,
        .suppress_frag_ndisc    = 1,
        .accept_ra_mtu          = 1,
        .stable_secret          = {
                .initialized = false,
        },
        .use_oif_addrs_only     = 0,
        .ignore_routes_with_linkdown = 0,
        .keep_addr_on_down      = 0,
        .seg6_enabled           = 0,
#ifdef CONFIG_IPV6_SEG6_HMAC
        .seg6_require_hmac      = 0,
#endif
        .enhanced_dad           = 1,
        .addr_gen_mode          = IN6_ADDR_GEN_MODE_EUI64,
        .disable_policy         = 0,
        .rpl_seg_enabled        = 0,
        .ioam6_enabled          = 0,
        .ioam6_id               = IOAM6_DEFAULT_IF_ID,
        .ioam6_id_wide          = IOAM6_DEFAULT_IF_ID_WIDE,
        .ndisc_evict_nocarrier  = 1,
        .ra_honor_pio_life      = 0,
        .ra_honor_pio_pflag     = 0,
        .force_forwarding       = 0,
};

static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
        .forwarding             = 0,
        .hop_limit              = IPV6_DEFAULT_HOPLIMIT,
        .mtu6                   = IPV6_MIN_MTU,
        .accept_ra              = 1,
        .accept_redirects       = 1,
        .autoconf               = 1,
        .force_mld_version      = 0,
        .mldv1_unsolicited_report_interval = 10 * HZ,
        .mldv2_unsolicited_report_interval = HZ,
        .dad_transmits          = 1,
        .rtr_solicits           = MAX_RTR_SOLICITATIONS,
        .rtr_solicit_interval   = RTR_SOLICITATION_INTERVAL,
        .rtr_solicit_max_interval = RTR_SOLICITATION_MAX_INTERVAL,
        .rtr_solicit_delay      = MAX_RTR_SOLICITATION_DELAY,
        .use_tempaddr           = 0,
        .temp_valid_lft         = TEMP_VALID_LIFETIME,
        .temp_prefered_lft      = TEMP_PREFERRED_LIFETIME,
        .regen_min_advance      = REGEN_MIN_ADVANCE,
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
        .max_addresses          = IPV6_MAX_ADDRESSES,
        .accept_ra_defrtr       = 1,
        .ra_defrtr_metric       = IP6_RT_PRIO_USER,
        .accept_ra_from_local   = 0,
        .accept_ra_min_hop_limit= 1,
        .accept_ra_min_lft      = 0,
        .accept_ra_pinfo        = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
        .accept_ra_rtr_pref     = 1,
        .rtr_probe_interval     = 60 * HZ,
#ifdef CONFIG_IPV6_ROUTE_INFO
        .accept_ra_rt_info_min_plen = 0,
        .accept_ra_rt_info_max_plen = 0,
#endif
#endif
        .proxy_ndp              = 0,
        .accept_source_route    = 0,    /* we do not accept RH0 by default. */
        .disable_ipv6           = 0,
        .accept_dad             = 1,
        .suppress_frag_ndisc    = 1,
        .accept_ra_mtu          = 1,
        .stable_secret          = {
                .initialized = false,
        },
        .use_oif_addrs_only     = 0,
        .ignore_routes_with_linkdown = 0,
        .keep_addr_on_down      = 0,
        .seg6_enabled           = 0,
#ifdef CONFIG_IPV6_SEG6_HMAC
        .seg6_require_hmac      = 0,
#endif
        .enhanced_dad           = 1,
        .addr_gen_mode          = IN6_ADDR_GEN_MODE_EUI64,
        .disable_policy         = 0,
        .rpl_seg_enabled        = 0,
        .ioam6_enabled          = 0,
        .ioam6_id               = IOAM6_DEFAULT_IF_ID,
        .ioam6_id_wide          = IOAM6_DEFAULT_IF_ID_WIDE,
        .ndisc_evict_nocarrier  = 1,
        .ra_honor_pio_life      = 0,
        .ra_honor_pio_pflag     = 0,
        .force_forwarding       = 0,
};

/* Check if link is ready: is it up and is a valid qdisc available */
static inline bool addrconf_link_ready(const struct net_device *dev)
{
        return netif_oper_up(dev) && !qdisc_tx_is_noop(dev);
}

static void addrconf_del_rs_timer(struct inet6_dev *idev)
{
        if (timer_delete(&idev->rs_timer))
                __in6_dev_put(idev);
}

static void addrconf_del_dad_work(struct inet6_ifaddr *ifp)
{
        if (cancel_delayed_work(&ifp->dad_work))
                __in6_ifa_put(ifp);
}

static void addrconf_mod_rs_timer(struct inet6_dev *idev,
                                  unsigned long when)
{
        if (!mod_timer(&idev->rs_timer, jiffies + when))
                in6_dev_hold(idev);
}

static void addrconf_mod_dad_work(struct inet6_ifaddr *ifp,
                                   unsigned long delay)
{
        in6_ifa_hold(ifp);
        if (mod_delayed_work(addrconf_wq, &ifp->dad_work, delay))
                in6_ifa_put(ifp);
}

static int snmp6_alloc_dev(struct inet6_dev *idev)
{
        int i;

        idev->stats.ipv6 = alloc_percpu_gfp(struct ipstats_mib, GFP_KERNEL_ACCOUNT);
        if (!idev->stats.ipv6)
                goto err_ip;

        for_each_possible_cpu(i) {
                struct ipstats_mib *addrconf_stats;
                addrconf_stats = per_cpu_ptr(idev->stats.ipv6, i);
                u64_stats_init(&addrconf_stats->syncp);
        }


        idev->stats.icmpv6dev = kzalloc_obj(struct icmpv6_mib_device);
        if (!idev->stats.icmpv6dev)
                goto err_icmp;
        idev->stats.icmpv6msgdev = kzalloc_obj(struct icmpv6msg_mib_device,
                                               GFP_KERNEL_ACCOUNT);
        if (!idev->stats.icmpv6msgdev)
                goto err_icmpmsg;

        return 0;

err_icmpmsg:
        kfree(idev->stats.icmpv6dev);
err_icmp:
        free_percpu(idev->stats.ipv6);
err_ip:
        return -ENOMEM;
}

static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
{
        struct inet6_dev *ndev;
        int err = -ENOMEM;

        ASSERT_RTNL();
        netdev_ops_assert_locked(dev);

        if (dev->mtu < IPV6_MIN_MTU && dev != blackhole_netdev)
                return ERR_PTR(-EINVAL);

        ndev = kzalloc_obj(*ndev, GFP_KERNEL_ACCOUNT);
        if (!ndev)
                return ERR_PTR(err);

        rwlock_init(&ndev->lock);
        ndev->dev = dev;
        INIT_LIST_HEAD(&ndev->addr_list);
        timer_setup(&ndev->rs_timer, addrconf_rs_timer, 0);
        memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));

        if (ndev->cnf.stable_secret.initialized)
                ndev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;

        ndev->cnf.mtu6 = dev->mtu;
        ndev->ra_mtu = 0;
        ndev->nd_parms = neigh_parms_alloc(dev, &nd_tbl);
        if (!ndev->nd_parms) {
                kfree(ndev);
                return ERR_PTR(err);
        }
        if (ndev->cnf.forwarding)
                netif_disable_lro(dev);
        /* We refer to the device */
        netdev_hold(dev, &ndev->dev_tracker, GFP_KERNEL);

        if (snmp6_alloc_dev(ndev) < 0) {
                netdev_dbg(dev, "%s: cannot allocate memory for statistics\n",
                           __func__);
                neigh_parms_release(&nd_tbl, ndev->nd_parms);
                netdev_put(dev, &ndev->dev_tracker);
                kfree(ndev);
                return ERR_PTR(err);
        }

        if (dev != blackhole_netdev) {
                if (snmp6_register_dev(ndev) < 0) {
                        netdev_dbg(dev, "%s: cannot create /proc/net/dev_snmp6/%s\n",
                                   __func__, dev->name);
                        goto err_release;
                }
        }
        /* One reference from device. */
        refcount_set(&ndev->refcnt, 1);

        if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))
                ndev->cnf.accept_dad = -1;

#if IS_ENABLED(CONFIG_IPV6_SIT)
        if (dev->type == ARPHRD_SIT && (dev->priv_flags & IFF_ISATAP)) {
                pr_info("%s: Disabled Multicast RS\n", dev->name);
                ndev->cnf.rtr_solicits = 0;
        }
#endif

        INIT_LIST_HEAD(&ndev->tempaddr_list);
        ndev->desync_factor = U32_MAX;
        if ((dev->flags&IFF_LOOPBACK) ||
            dev->type == ARPHRD_TUNNEL ||
            dev->type == ARPHRD_TUNNEL6 ||
            dev->type == ARPHRD_SIT ||
            dev->type == ARPHRD_NONE) {
                ndev->cnf.use_tempaddr = -1;
        }

        ndev->token = in6addr_any;

        if (netif_running(dev) && addrconf_link_ready(dev))
                ndev->if_flags |= IF_READY;

        ipv6_mc_init_dev(ndev);
        ndev->tstamp = jiffies;
        if (dev != blackhole_netdev) {
                err = addrconf_sysctl_register(ndev);
                if (err) {
                        ipv6_mc_destroy_dev(ndev);
                        snmp6_unregister_dev(ndev);
                        goto err_release;
                }
        }
        /* protected by rtnl_lock */
        rcu_assign_pointer(dev->ip6_ptr, ndev);

        if (dev != blackhole_netdev) {
                /* Join interface-local all-node multicast group */
                ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allnodes);

                /* Join all-node multicast group */
                ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes);

                /* Join all-router multicast group if forwarding is set */
                if (ndev->cnf.forwarding && (dev->flags & IFF_MULTICAST))
                        ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
        }
        return ndev;

err_release:
        neigh_parms_release(&nd_tbl, ndev->nd_parms);
        ndev->dead = 1;
        in6_dev_finish_destroy(ndev);
        return ERR_PTR(err);
}

static struct inet6_dev *ipv6_find_idev(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = __in6_dev_get(dev);
        if (!idev) {
                idev = ipv6_add_dev(dev);
                if (IS_ERR(idev))
                        return idev;
        }

        if (dev->flags&IFF_UP)
                ipv6_mc_up(idev);
        return idev;
}

static int inet6_netconf_msgsize_devconf(int type)
{
        int size =  NLMSG_ALIGN(sizeof(struct netconfmsg))
                    + nla_total_size(4);        /* NETCONFA_IFINDEX */
        bool all = false;

        if (type == NETCONFA_ALL)
                all = true;

        if (all || type == NETCONFA_FORWARDING)
                size += nla_total_size(4);
#ifdef CONFIG_IPV6_MROUTE
        if (all || type == NETCONFA_MC_FORWARDING)
                size += nla_total_size(4);
#endif
        if (all || type == NETCONFA_PROXY_NEIGH)
                size += nla_total_size(4);

        if (all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN)
                size += nla_total_size(4);

        return size;
}

static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
                                      struct ipv6_devconf *devconf, u32 portid,
                                      u32 seq, int event, unsigned int flags,
                                      int type)
{
        struct nlmsghdr  *nlh;
        struct netconfmsg *ncm;
        bool all = false;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
                        flags);
        if (!nlh)
                return -EMSGSIZE;

        if (type == NETCONFA_ALL)
                all = true;

        ncm = nlmsg_data(nlh);
        ncm->ncm_family = AF_INET6;

        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
                goto nla_put_failure;

        if (!devconf)
                goto out;

        if ((all || type == NETCONFA_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_FORWARDING,
                        READ_ONCE(devconf->forwarding)) < 0)
                goto nla_put_failure;
#ifdef CONFIG_IPV6_MROUTE
        if ((all || type == NETCONFA_MC_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_MC_FORWARDING,
                        atomic_read(&devconf->mc_forwarding)) < 0)
                goto nla_put_failure;
#endif
        if ((all || type == NETCONFA_PROXY_NEIGH) &&
            nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
                        READ_ONCE(devconf->proxy_ndp)) < 0)
                goto nla_put_failure;

        if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
            nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                        READ_ONCE(devconf->ignore_routes_with_linkdown)) < 0)
                goto nla_put_failure;

out:
        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

void inet6_netconf_notify_devconf(struct net *net, int event, int type,
                                  int ifindex, struct ipv6_devconf *devconf)
{
        struct sk_buff *skb;
        int err = -ENOBUFS;

        skb = nlmsg_new(inet6_netconf_msgsize_devconf(type), GFP_KERNEL);
        if (!skb)
                goto errout;

        err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
                                         event, 0, type);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_NETCONF, NULL, GFP_KERNEL);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_IPV6_NETCONF, err);
}

static const struct nla_policy devconf_ipv6_policy[NETCONFA_MAX+1] = {
        [NETCONFA_IFINDEX]      = { .len = sizeof(int) },
        [NETCONFA_FORWARDING]   = { .len = sizeof(int) },
        [NETCONFA_PROXY_NEIGH]  = { .len = sizeof(int) },
        [NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]  = { .len = sizeof(int) },
};

static int inet6_netconf_valid_get_req(struct sk_buff *skb,
                                       const struct nlmsghdr *nlh,
                                       struct nlattr **tb,
                                       struct netlink_ext_ack *extack)
{
        int i, err;

        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(struct netconfmsg))) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid header for netconf get request");
                return -EINVAL;
        }

        if (!netlink_strict_get_check(skb))
                return nlmsg_parse_deprecated(nlh, sizeof(struct netconfmsg),
                                              tb, NETCONFA_MAX,
                                              devconf_ipv6_policy, extack);

        err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct netconfmsg),
                                            tb, NETCONFA_MAX,
                                            devconf_ipv6_policy, extack);
        if (err)
                return err;

        for (i = 0; i <= NETCONFA_MAX; i++) {
                if (!tb[i])
                        continue;

                switch (i) {
                case NETCONFA_IFINDEX:
                        break;
                default:
                        NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in netconf get request");
                        return -EINVAL;
                }
        }

        return 0;
}

static int inet6_netconf_get_devconf(struct sk_buff *in_skb,
                                     struct nlmsghdr *nlh,
                                     struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(in_skb->sk);
        struct nlattr *tb[NETCONFA_MAX+1];
        struct inet6_dev *in6_dev = NULL;
        struct net_device *dev = NULL;
        struct sk_buff *skb;
        struct ipv6_devconf *devconf;
        int ifindex;
        int err;

        err = inet6_netconf_valid_get_req(in_skb, nlh, tb, extack);
        if (err < 0)
                return err;

        if (!tb[NETCONFA_IFINDEX])
                return -EINVAL;

        err = -EINVAL;
        ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
        switch (ifindex) {
        case NETCONFA_IFINDEX_ALL:
                devconf = net->ipv6.devconf_all;
                break;
        case NETCONFA_IFINDEX_DEFAULT:
                devconf = net->ipv6.devconf_dflt;
                break;
        default:
                dev = dev_get_by_index(net, ifindex);
                if (!dev)
                        return -EINVAL;
                in6_dev = in6_dev_get(dev);
                if (!in6_dev)
                        goto errout;
                devconf = &in6_dev->cnf;
                break;
        }

        err = -ENOBUFS;
        skb = nlmsg_new(inet6_netconf_msgsize_devconf(NETCONFA_ALL), GFP_KERNEL);
        if (!skb)
                goto errout;

        err = inet6_netconf_fill_devconf(skb, ifindex, devconf,
                                         NETLINK_CB(in_skb).portid,
                                         nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
                                         NETCONFA_ALL);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
errout:
        if (in6_dev)
                in6_dev_put(in6_dev);
        dev_put(dev);
        return err;
}

/* Combine dev_addr_genid and dev_base_seq to detect changes.
 */
static u32 inet6_base_seq(const struct net *net)
{
        u32 res = atomic_read(&net->ipv6.dev_addr_genid) +
                  READ_ONCE(net->dev_base_seq);

        /* Must not return 0 (see nl_dump_check_consistent()).
         * Chose a value far away from 0.
         */
        if (!res)
                res = 0x80000000;
        return res;
}

static int inet6_netconf_dump_devconf(struct sk_buff *skb,
                                      struct netlink_callback *cb)
{
        const struct nlmsghdr *nlh = cb->nlh;
        struct net *net = sock_net(skb->sk);
        struct {
                unsigned long ifindex;
                unsigned int all_default;
        } *ctx = (void *)cb->ctx;
        struct net_device *dev;
        struct inet6_dev *idev;
        int err = 0;

        if (cb->strict_check) {
                struct netlink_ext_ack *extack = cb->extack;
                struct netconfmsg *ncm;

                if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ncm))) {
                        NL_SET_ERR_MSG_MOD(extack, "Invalid header for netconf dump request");
                        return -EINVAL;
                }

                if (nlmsg_attrlen(nlh, sizeof(*ncm))) {
                        NL_SET_ERR_MSG_MOD(extack, "Invalid data after header in netconf dump request");
                        return -EINVAL;
                }
        }

        rcu_read_lock();
        for_each_netdev_dump(net, dev, ctx->ifindex) {
                idev = __in6_dev_get(dev);
                if (!idev)
                        continue;
                err = inet6_netconf_fill_devconf(skb, dev->ifindex,
                                                 &idev->cnf,
                                                 NETLINK_CB(cb->skb).portid,
                                                 nlh->nlmsg_seq,
                                                 RTM_NEWNETCONF,
                                                 NLM_F_MULTI,
                                                 NETCONFA_ALL);
                if (err < 0)
                        goto done;
        }
        if (ctx->all_default == 0) {
                err = inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
                                                 net->ipv6.devconf_all,
                                                 NETLINK_CB(cb->skb).portid,
                                                 nlh->nlmsg_seq,
                                                 RTM_NEWNETCONF, NLM_F_MULTI,
                                                 NETCONFA_ALL);
                if (err < 0)
                        goto done;
                ctx->all_default++;
        }
        if (ctx->all_default == 1) {
                err = inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
                                                 net->ipv6.devconf_dflt,
                                                 NETLINK_CB(cb->skb).portid,
                                                 nlh->nlmsg_seq,
                                                 RTM_NEWNETCONF, NLM_F_MULTI,
                                                 NETCONFA_ALL);
                if (err < 0)
                        goto done;
                ctx->all_default++;
        }
done:
        rcu_read_unlock();
        return err;
}

#ifdef CONFIG_SYSCTL
static void dev_forward_change(struct inet6_dev *idev)
{
        struct net_device *dev;
        struct inet6_ifaddr *ifa;
        LIST_HEAD(tmp_addr_list);

        if (!idev)
                return;
        dev = idev->dev;
        if (idev->cnf.forwarding)
                dev_disable_lro(dev);
        if (dev->flags & IFF_MULTICAST) {
                if (idev->cnf.forwarding) {
                        ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
                        ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allrouters);
                        ipv6_dev_mc_inc(dev, &in6addr_sitelocal_allrouters);
                } else {
                        ipv6_dev_mc_dec(dev, &in6addr_linklocal_allrouters);
                        ipv6_dev_mc_dec(dev, &in6addr_interfacelocal_allrouters);
                        ipv6_dev_mc_dec(dev, &in6addr_sitelocal_allrouters);
                }
        }

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifa, &idev->addr_list, if_list) {
                if (ifa->flags&IFA_F_TENTATIVE)
                        continue;
                list_add_tail(&ifa->if_list_aux, &tmp_addr_list);
        }
        read_unlock_bh(&idev->lock);

        while (!list_empty(&tmp_addr_list)) {
                ifa = list_first_entry(&tmp_addr_list,
                                       struct inet6_ifaddr, if_list_aux);
                list_del(&ifa->if_list_aux);
                if (idev->cnf.forwarding)
                        addrconf_join_anycast(ifa);
                else
                        addrconf_leave_anycast(ifa);
        }

        inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,
                                     NETCONFA_FORWARDING,
                                     dev->ifindex, &idev->cnf);
}


static void addrconf_forward_change(struct net *net, __s32 newf)
{
        struct net_device *dev;
        struct inet6_dev *idev;

        for_each_netdev(net, dev) {
                idev = __in6_dev_get_rtnl_net(dev);
                if (idev) {
                        int changed = (!idev->cnf.forwarding) ^ (!newf);
                        /* Disabling all.forwarding sets 0 to force_forwarding for all interfaces */
                        if (newf == 0)
                                WRITE_ONCE(idev->cnf.force_forwarding, 0);

                        WRITE_ONCE(idev->cnf.forwarding, newf);
                        if (changed)
                                dev_forward_change(idev);
                }
        }
}

static int addrconf_fixup_forwarding(const struct ctl_table *table, int *p, int newf)
{
        struct net *net = (struct net *)table->extra2;
        int old;

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        old = *p;
        WRITE_ONCE(*p, newf);

        if (p == &net->ipv6.devconf_dflt->forwarding) {
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORWARDING,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);
                rtnl_net_unlock(net);
                return 0;
        }

        if (p == &net->ipv6.devconf_all->forwarding) {
                int old_dflt = net->ipv6.devconf_dflt->forwarding;

                WRITE_ONCE(net->ipv6.devconf_dflt->forwarding, newf);
                if ((!newf) ^ (!old_dflt))
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORWARDING,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);

                addrconf_forward_change(net, newf);
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORWARDING,
                                                     NETCONFA_IFINDEX_ALL,
                                                     net->ipv6.devconf_all);
        } else if ((!newf) ^ (!old))
                dev_forward_change((struct inet6_dev *)table->extra1);
        rtnl_net_unlock(net);

        if (newf)
                rt6_purge_dflt_routers(net);
        return 1;
}

static void addrconf_linkdown_change(struct net *net, __s32 newf)
{
        struct net_device *dev;
        struct inet6_dev *idev;

        for_each_netdev(net, dev) {
                idev = __in6_dev_get_rtnl_net(dev);
                if (idev) {
                        int changed = (!idev->cnf.ignore_routes_with_linkdown) ^ (!newf);

                        WRITE_ONCE(idev->cnf.ignore_routes_with_linkdown, newf);
                        if (changed)
                                inet6_netconf_notify_devconf(dev_net(dev),
                                                             RTM_NEWNETCONF,
                                                             NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                                                             dev->ifindex,
                                                             &idev->cnf);
                }
        }
}

static int addrconf_fixup_linkdown(const struct ctl_table *table, int *p, int newf)
{
        struct net *net = (struct net *)table->extra2;
        int old;

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        old = *p;
        WRITE_ONCE(*p, newf);

        if (p == &net->ipv6.devconf_dflt->ignore_routes_with_linkdown) {
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net,
                                                     RTM_NEWNETCONF,
                                                     NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);
                rtnl_net_unlock(net);
                return 0;
        }

        if (p == &net->ipv6.devconf_all->ignore_routes_with_linkdown) {
                WRITE_ONCE(net->ipv6.devconf_dflt->ignore_routes_with_linkdown, newf);
                addrconf_linkdown_change(net, newf);
                if ((!newf) ^ (!old))
                        inet6_netconf_notify_devconf(net,
                                                     RTM_NEWNETCONF,
                                                     NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                                                     NETCONFA_IFINDEX_ALL,
                                                     net->ipv6.devconf_all);
        }

        rtnl_net_unlock(net);

        return 1;
}

#endif

/* Nobody refers to this ifaddr, destroy it */
void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
{
        WARN_ON(!hlist_unhashed(&ifp->addr_lst));

#ifdef NET_REFCNT_DEBUG
        pr_debug("%s\n", __func__);
#endif

        in6_dev_put(ifp->idev);

        if (cancel_delayed_work(&ifp->dad_work))
                pr_notice("delayed DAD work was pending while freeing ifa=%p\n",
                          ifp);

        if (ifp->state != INET6_IFADDR_STATE_DEAD) {
                pr_warn("Freeing alive inet6 address %p\n", ifp);
                return;
        }

        kfree_rcu(ifp, rcu);
}

static void
ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
{
        struct list_head *p;
        int ifp_scope = ipv6_addr_src_scope(&ifp->addr);

        /*
         * Each device address list is sorted in order of scope -
         * global before linklocal.
         */
        list_for_each(p, &idev->addr_list) {
                struct inet6_ifaddr *ifa
                        = list_entry(p, struct inet6_ifaddr, if_list);
                if (ifp_scope > ipv6_addr_src_scope(&ifa->addr))
                        break;
        }

        list_add_tail_rcu(&ifp->if_list, p);
}

static u32 inet6_addr_hash(const struct net *net, const struct in6_addr *addr)
{
        u32 val = __ipv6_addr_jhash(addr, net_hash_mix(net));

        return hash_32(val, IN6_ADDR_HSIZE_SHIFT);
}

static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
                               struct net_device *dev, unsigned int hash)
{
        struct inet6_ifaddr *ifp;

        hlist_for_each_entry(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
                if (ipv6_addr_equal(&ifp->addr, addr)) {
                        if (!dev || ifp->idev->dev == dev)
                                return true;
                }
        }
        return false;
}

static int ipv6_add_addr_hash(struct net_device *dev, struct inet6_ifaddr *ifa)
{
        struct net *net = dev_net(dev);
        unsigned int hash = inet6_addr_hash(net, &ifa->addr);
        int err = 0;

        spin_lock_bh(&net->ipv6.addrconf_hash_lock);

        /* Ignore adding duplicate addresses on an interface */
        if (ipv6_chk_same_addr(net, &ifa->addr, dev, hash)) {
                netdev_dbg(dev, "ipv6_add_addr: already assigned\n");
                err = -EEXIST;
        } else {
                hlist_add_head_rcu(&ifa->addr_lst, &net->ipv6.inet6_addr_lst[hash]);
        }

        spin_unlock_bh(&net->ipv6.addrconf_hash_lock);

        return err;
}

/* On success it returns ifp with increased reference count */

static struct inet6_ifaddr *
ipv6_add_addr(struct inet6_dev *idev, struct ifa6_config *cfg,
              bool can_block, struct netlink_ext_ack *extack)
{
        gfp_t gfp_flags = can_block ? GFP_KERNEL : GFP_ATOMIC;
        int addr_type = ipv6_addr_type(cfg->pfx);
        struct net *net = dev_net(idev->dev);
        struct inet6_ifaddr *ifa = NULL;
        struct fib6_info *f6i = NULL;
        int err = 0;

        if (addr_type == IPV6_ADDR_ANY) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid address");
                return ERR_PTR(-EADDRNOTAVAIL);
        } else if (addr_type & IPV6_ADDR_MULTICAST &&
                   !(cfg->ifa_flags & IFA_F_MCAUTOJOIN)) {
                NL_SET_ERR_MSG_MOD(extack, "Cannot assign multicast address without \"IFA_F_MCAUTOJOIN\" flag");
                return ERR_PTR(-EADDRNOTAVAIL);
        } else if (!(idev->dev->flags & IFF_LOOPBACK) &&
                   !netif_is_l3_master(idev->dev) &&
                   addr_type & IPV6_ADDR_LOOPBACK) {
                NL_SET_ERR_MSG_MOD(extack, "Cannot assign loopback address on this device");
                return ERR_PTR(-EADDRNOTAVAIL);
        }

        if (idev->dead) {
                NL_SET_ERR_MSG_MOD(extack, "device is going away");
                err = -ENODEV;
                goto out;
        }

        if (idev->cnf.disable_ipv6) {
                NL_SET_ERR_MSG_MOD(extack, "IPv6 is disabled on this device");
                err = -EACCES;
                goto out;
        }

        /* validator notifier needs to be blocking;
         * do not call in atomic context
         */
        if (can_block) {
                struct in6_validator_info i6vi = {
                        .i6vi_addr = *cfg->pfx,
                        .i6vi_dev = idev,
                        .extack = extack,
                };

                err = inet6addr_validator_notifier_call_chain(NETDEV_UP, &i6vi);
                err = notifier_to_errno(err);
                if (err < 0)
                        goto out;
        }

        ifa = kzalloc_obj(*ifa, gfp_flags | __GFP_ACCOUNT);
        if (!ifa) {
                err = -ENOBUFS;
                goto out;
        }

        f6i = addrconf_f6i_alloc(net, idev, cfg->pfx, false, gfp_flags, extack);
        if (IS_ERR(f6i)) {
                err = PTR_ERR(f6i);
                f6i = NULL;
                goto out;
        }

        neigh_parms_data_state_setall(idev->nd_parms);

        ifa->addr = *cfg->pfx;
        if (cfg->peer_pfx)
                ifa->peer_addr = *cfg->peer_pfx;

        spin_lock_init(&ifa->lock);
        INIT_DELAYED_WORK(&ifa->dad_work, addrconf_dad_work);
        INIT_HLIST_NODE(&ifa->addr_lst);
        ifa->scope = cfg->scope;
        ifa->prefix_len = cfg->plen;
        ifa->rt_priority = cfg->rt_priority;
        ifa->flags = cfg->ifa_flags;
        ifa->ifa_proto = cfg->ifa_proto;
        /* No need to add the TENTATIVE flag for addresses with NODAD */
        if (!(cfg->ifa_flags & IFA_F_NODAD))
                ifa->flags |= IFA_F_TENTATIVE;
        ifa->valid_lft = cfg->valid_lft;
        ifa->prefered_lft = cfg->preferred_lft;
        ifa->cstamp = ifa->tstamp = jiffies;
        ifa->tokenized = false;

        ifa->rt = f6i;

        ifa->idev = idev;
        in6_dev_hold(idev);

        /* For caller */
        refcount_set(&ifa->refcnt, 1);

        rcu_read_lock();

        err = ipv6_add_addr_hash(idev->dev, ifa);
        if (err < 0) {
                rcu_read_unlock();
                goto out;
        }

        write_lock_bh(&idev->lock);

        /* Add to inet6_dev unicast addr list. */
        ipv6_link_dev_addr(idev, ifa);

        if (ifa->flags&IFA_F_TEMPORARY) {
                list_add(&ifa->tmp_list, &idev->tempaddr_list);
                in6_ifa_hold(ifa);
        }

        in6_ifa_hold(ifa);
        write_unlock_bh(&idev->lock);

        rcu_read_unlock();

        inet6addr_notifier_call_chain(NETDEV_UP, ifa);
out:
        if (unlikely(err < 0)) {
                fib6_info_release(f6i);

                if (ifa) {
                        if (ifa->idev)
                                in6_dev_put(ifa->idev);
                        kfree(ifa);
                }
                ifa = ERR_PTR(err);
        }

        return ifa;
}

enum cleanup_prefix_rt_t {
        CLEANUP_PREFIX_RT_NOP,    /* no cleanup action for prefix route */
        CLEANUP_PREFIX_RT_DEL,    /* delete the prefix route */
        CLEANUP_PREFIX_RT_EXPIRE, /* update the lifetime of the prefix route */
};

/*
 * Check, whether the prefix for ifp would still need a prefix route
 * after deleting ifp. The function returns one of the CLEANUP_PREFIX_RT_*
 * constants.
 *
 * 1) we don't purge prefix if address was not permanent.
 *    prefix is managed by its own lifetime.
 * 2) we also don't purge, if the address was IFA_F_NOPREFIXROUTE.
 * 3) if there are no addresses, delete prefix.
 * 4) if there are still other permanent address(es),
 *    corresponding prefix is still permanent.
 * 5) if there are still other addresses with IFA_F_NOPREFIXROUTE,
 *    don't purge the prefix, assume user space is managing it.
 * 6) otherwise, update prefix lifetime to the
 *    longest valid lifetime among the corresponding
 *    addresses on the device.
 *    Note: subsequent RA will update lifetime.
 **/
static enum cleanup_prefix_rt_t
check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires)
{
        struct inet6_ifaddr *ifa;
        struct inet6_dev *idev = ifp->idev;
        unsigned long lifetime;
        enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_DEL;

        *expires = jiffies;

        list_for_each_entry(ifa, &idev->addr_list, if_list) {
                if (ifa == ifp)
                        continue;
                if (ifa->prefix_len != ifp->prefix_len ||
                    !ipv6_prefix_equal(&ifa->addr, &ifp->addr,
                                       ifp->prefix_len))
                        continue;
                if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))
                        return CLEANUP_PREFIX_RT_NOP;

                action = CLEANUP_PREFIX_RT_EXPIRE;

                spin_lock(&ifa->lock);

                lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
                /*
                 * Note: Because this address is
                 * not permanent, lifetime <
                 * LONG_MAX / HZ here.
                 */
                if (time_before(*expires, ifa->tstamp + lifetime * HZ))
                        *expires = ifa->tstamp + lifetime * HZ;
                spin_unlock(&ifa->lock);
        }

        return action;
}

static void
cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires,
                     bool del_rt, bool del_peer)
{
        struct fib6_table *table;
        struct fib6_info *f6i;

        f6i = addrconf_get_prefix_route(del_peer ? &ifp->peer_addr : &ifp->addr,
                                        ifp->prefix_len,
                                        ifp->idev->dev, 0, RTF_DEFAULT, true);
        if (f6i) {
                if (del_rt)
                        ip6_del_rt(dev_net(ifp->idev->dev), f6i, false);
                else {
                        if (!(f6i->fib6_flags & RTF_EXPIRES)) {
                                table = f6i->fib6_table;
                                spin_lock_bh(&table->tb6_lock);

                                fib6_set_expires(f6i, expires);
                                fib6_add_gc_list(f6i);

                                spin_unlock_bh(&table->tb6_lock);
                        }
                        fib6_info_release(f6i);
                }
        }
}


/* This function wants to get referenced ifp and releases it before return */

static void ipv6_del_addr(struct inet6_ifaddr *ifp)
{
        enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP;
        struct net *net = dev_net(ifp->idev->dev);
        unsigned long expires;
        int state;

        ASSERT_RTNL();

        spin_lock_bh(&ifp->lock);
        state = ifp->state;
        ifp->state = INET6_IFADDR_STATE_DEAD;
        spin_unlock_bh(&ifp->lock);

        if (state == INET6_IFADDR_STATE_DEAD)
                goto out;

        spin_lock_bh(&net->ipv6.addrconf_hash_lock);
        hlist_del_init_rcu(&ifp->addr_lst);
        spin_unlock_bh(&net->ipv6.addrconf_hash_lock);

        write_lock_bh(&ifp->idev->lock);

        if (ifp->flags&IFA_F_TEMPORARY) {
                list_del(&ifp->tmp_list);
                if (ifp->ifpub) {
                        in6_ifa_put(ifp->ifpub);
                        ifp->ifpub = NULL;
                }
                __in6_ifa_put(ifp);
        }

        if (!(ifp->flags & IFA_F_NOPREFIXROUTE))
                action = check_cleanup_prefix_route(ifp, &expires);

        list_del_rcu(&ifp->if_list);
        __in6_ifa_put(ifp);

        write_unlock_bh(&ifp->idev->lock);

        addrconf_del_dad_work(ifp);

        ipv6_ifa_notify(RTM_DELADDR, ifp);

        inet6addr_notifier_call_chain(NETDEV_DOWN, ifp);

        if (action != CLEANUP_PREFIX_RT_NOP) {
                cleanup_prefix_route(ifp, expires,
                        action == CLEANUP_PREFIX_RT_DEL, false);
        }

        /* clean up prefsrc entries */
        rt6_remove_prefsrc(ifp);
out:
        in6_ifa_put(ifp);
}

static unsigned long ipv6_get_regen_advance(const struct inet6_dev *idev)
{
        return READ_ONCE(idev->cnf.regen_min_advance) +
                READ_ONCE(idev->cnf.regen_max_retry) *
                READ_ONCE(idev->cnf.dad_transmits) *
                max(NEIGH_VAR(idev->nd_parms, RETRANS_TIME), HZ/100) / HZ;
}

static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
{
        struct inet6_dev *idev = ifp->idev;
        unsigned long tmp_tstamp, age;
        unsigned long regen_advance;
        unsigned long now = jiffies;
        u32 if_public_preferred_lft;
        s32 cnf_temp_preferred_lft;
        struct inet6_ifaddr *ift;
        struct ifa6_config cfg;
        long max_desync_factor;
        struct in6_addr addr;
        int ret = 0;

        write_lock_bh(&idev->lock);

retry:
        in6_dev_hold(idev);
        if (READ_ONCE(idev->cnf.use_tempaddr) <= 0) {
                write_unlock_bh(&idev->lock);
                pr_info("%s: use_tempaddr is disabled\n", __func__);
                in6_dev_put(idev);
                ret = -1;
                goto out;
        }
        spin_lock_bh(&ifp->lock);
        if (ifp->regen_count++ >= READ_ONCE(idev->cnf.regen_max_retry)) {
                WRITE_ONCE(idev->cnf.use_tempaddr, -1); /*XXX*/
                spin_unlock_bh(&ifp->lock);
                write_unlock_bh(&idev->lock);
                pr_warn("%s: regeneration time exceeded - disabled temporary address support\n",
                        __func__);
                in6_dev_put(idev);
                ret = -1;
                goto out;
        }
        in6_ifa_hold(ifp);
        memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
        ipv6_gen_rnd_iid(&addr);

        age = (now - ifp->tstamp) / HZ;

        regen_advance = ipv6_get_regen_advance(idev);

        /* recalculate max_desync_factor each time and update
         * idev->desync_factor if it's larger
         */
        cnf_temp_preferred_lft = READ_ONCE(idev->cnf.temp_prefered_lft);
        max_desync_factor = min_t(long,
                                  READ_ONCE(idev->cnf.max_desync_factor),
                                  cnf_temp_preferred_lft - regen_advance);

        if (unlikely(idev->desync_factor > max_desync_factor)) {
                if (max_desync_factor > 0) {
                        get_random_bytes(&idev->desync_factor,
                                         sizeof(idev->desync_factor));
                        idev->desync_factor %= max_desync_factor;
                } else {
                        idev->desync_factor = 0;
                }
        }

        if_public_preferred_lft = ifp->prefered_lft;

        memset(&cfg, 0, sizeof(cfg));
        cfg.valid_lft = min_t(__u32, ifp->valid_lft,
                              READ_ONCE(idev->cnf.temp_valid_lft) + age);
        cfg.preferred_lft = cnf_temp_preferred_lft + age - idev->desync_factor;
        cfg.preferred_lft = min_t(__u32, if_public_preferred_lft, cfg.preferred_lft);
        cfg.preferred_lft = min_t(__u32, cfg.valid_lft, cfg.preferred_lft);

        cfg.plen = ifp->prefix_len;
        tmp_tstamp = ifp->tstamp;
        spin_unlock_bh(&ifp->lock);

        write_unlock_bh(&idev->lock);

        /* From RFC 4941:
         *
         *     A temporary address is created only if this calculated Preferred
         *     Lifetime is greater than REGEN_ADVANCE time units.  In
         *     particular, an implementation must not create a temporary address
         *     with a zero Preferred Lifetime.
         *
         *     ...
         *
         *     When creating a temporary address, the lifetime values MUST be
         *     derived from the corresponding prefix as follows:
         *
         *     ...
         *
         *     *  Its Preferred Lifetime is the lower of the Preferred Lifetime
         *        of the public address or TEMP_PREFERRED_LIFETIME -
         *        DESYNC_FACTOR.
         *
         * To comply with the RFC's requirements, clamp the preferred lifetime
         * to a minimum of regen_advance, unless that would exceed valid_lft or
         * ifp->prefered_lft.
         *
         * Use age calculation as in addrconf_verify to avoid unnecessary
         * temporary addresses being generated.
         */
        age = (now - tmp_tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
        if (cfg.preferred_lft <= regen_advance + age) {
                cfg.preferred_lft = regen_advance + age + 1;
                if (cfg.preferred_lft > cfg.valid_lft ||
                    cfg.preferred_lft > if_public_preferred_lft) {
                        in6_ifa_put(ifp);
                        in6_dev_put(idev);
                        ret = -1;
                        goto out;
                }
        }

        cfg.ifa_flags = IFA_F_TEMPORARY;
        /* set in addrconf_prefix_rcv() */
        if (ifp->flags & IFA_F_OPTIMISTIC)
                cfg.ifa_flags |= IFA_F_OPTIMISTIC;

        cfg.pfx = &addr;
        cfg.scope = ipv6_addr_scope(cfg.pfx);

        ift = ipv6_add_addr(idev, &cfg, block, NULL);
        if (IS_ERR(ift)) {
                in6_ifa_put(ifp);
                in6_dev_put(idev);
                pr_info("%s: retry temporary address regeneration\n", __func__);
                write_lock_bh(&idev->lock);
                goto retry;
        }

        spin_lock_bh(&ift->lock);
        ift->ifpub = ifp;
        ift->cstamp = now;
        ift->tstamp = tmp_tstamp;
        spin_unlock_bh(&ift->lock);

        addrconf_dad_start(ift);
        in6_ifa_put(ift);
        in6_dev_put(idev);
out:
        return ret;
}

/*
 *      Choose an appropriate source address (RFC3484)
 */
enum {
        IPV6_SADDR_RULE_INIT = 0,
        IPV6_SADDR_RULE_LOCAL,
        IPV6_SADDR_RULE_SCOPE,
        IPV6_SADDR_RULE_PREFERRED,
#ifdef CONFIG_IPV6_MIP6
        IPV6_SADDR_RULE_HOA,
#endif
        IPV6_SADDR_RULE_OIF,
        IPV6_SADDR_RULE_LABEL,
        IPV6_SADDR_RULE_PRIVACY,
        IPV6_SADDR_RULE_ORCHID,
        IPV6_SADDR_RULE_PREFIX,
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        IPV6_SADDR_RULE_NOT_OPTIMISTIC,
#endif
        IPV6_SADDR_RULE_MAX
};

struct ipv6_saddr_score {
        int                     rule;
        int                     addr_type;
        struct inet6_ifaddr     *ifa;
        DECLARE_BITMAP(scorebits, IPV6_SADDR_RULE_MAX);
        int                     scopedist;
        int                     matchlen;
};

struct ipv6_saddr_dst {
        const struct in6_addr *addr;
        int ifindex;
        int scope;
        int label;
        unsigned int prefs;
};

static inline int ipv6_saddr_preferred(int type)
{
        if (type & (IPV6_ADDR_MAPPED|IPV6_ADDR_COMPATv4|IPV6_ADDR_LOOPBACK))
                return 1;
        return 0;
}

static bool ipv6_use_optimistic_addr(const struct net *net,
                                     const struct inet6_dev *idev)
{
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        if (!idev)
                return false;
        if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
            !READ_ONCE(idev->cnf.optimistic_dad))
                return false;
        if (!READ_ONCE(net->ipv6.devconf_all->use_optimistic) &&
            !READ_ONCE(idev->cnf.use_optimistic))
                return false;

        return true;
#else
        return false;
#endif
}

static bool ipv6_allow_optimistic_dad(const struct net *net,
                                      const struct inet6_dev *idev)
{
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        if (!idev)
                return false;
        if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
            !READ_ONCE(idev->cnf.optimistic_dad))
                return false;

        return true;
#else
        return false;
#endif
}

static int ipv6_get_saddr_eval(struct net *net,
                               struct ipv6_saddr_score *score,
                               struct ipv6_saddr_dst *dst,
                               int i)
{
        int ret;

        if (i <= score->rule) {
                switch (i) {
                case IPV6_SADDR_RULE_SCOPE:
                        ret = score->scopedist;
                        break;
                case IPV6_SADDR_RULE_PREFIX:
                        ret = score->matchlen;
                        break;
                default:
                        ret = !!test_bit(i, score->scorebits);
                }
                goto out;
        }

        switch (i) {
        case IPV6_SADDR_RULE_INIT:
                /* Rule 0: remember if hiscore is not ready yet */
                ret = !!score->ifa;
                break;
        case IPV6_SADDR_RULE_LOCAL:
                /* Rule 1: Prefer same address */
                ret = ipv6_addr_equal(&score->ifa->addr, dst->addr);
                break;
        case IPV6_SADDR_RULE_SCOPE:
                /* Rule 2: Prefer appropriate scope
                 *
                 *      ret
                 *       ^
                 *    -1 |  d 15
                 *    ---+--+-+---> scope
                 *       |
                 *       |             d is scope of the destination.
                 *  B-d  |  \
                 *       |   \      <- smaller scope is better if
                 *  B-15 |    \        if scope is enough for destination.
                 *       |             ret = B - scope (-1 <= scope >= d <= 15).
                 * d-C-1 | /
                 *       |/         <- greater is better
                 *   -C  /             if scope is not enough for destination.
                 *      /|             ret = scope - C (-1 <= d < scope <= 15).
                 *
                 * d - C - 1 < B -15 (for all -1 <= d <= 15).
                 * C > d + 14 - B >= 15 + 14 - B = 29 - B.
                 * Assume B = 0 and we get C > 29.
                 */
                ret = __ipv6_addr_src_scope(score->addr_type);
                if (ret >= dst->scope)
                        ret = -ret;
                else
                        ret -= 128;     /* 30 is enough */
                score->scopedist = ret;
                break;
        case IPV6_SADDR_RULE_PREFERRED:
            {
                /* Rule 3: Avoid deprecated and optimistic addresses */
                u8 avoid = IFA_F_DEPRECATED;

                if (!ipv6_use_optimistic_addr(net, score->ifa->idev))
                        avoid |= IFA_F_OPTIMISTIC;
                ret = ipv6_saddr_preferred(score->addr_type) ||
                      !(score->ifa->flags & avoid);
                break;
            }
#ifdef CONFIG_IPV6_MIP6
        case IPV6_SADDR_RULE_HOA:
            {
                /* Rule 4: Prefer home address */
                int prefhome = !(dst->prefs & IPV6_PREFER_SRC_COA);
                ret = !(score->ifa->flags & IFA_F_HOMEADDRESS) ^ prefhome;
                break;
            }
#endif
        case IPV6_SADDR_RULE_OIF:
                /* Rule 5: Prefer outgoing interface */
                ret = (!dst->ifindex ||
                       dst->ifindex == score->ifa->idev->dev->ifindex);
                break;
        case IPV6_SADDR_RULE_LABEL:
                /* Rule 6: Prefer matching label */
                ret = ipv6_addr_label(net,
                                      &score->ifa->addr, score->addr_type,
                                      score->ifa->idev->dev->ifindex) == dst->label;
                break;
        case IPV6_SADDR_RULE_PRIVACY:
            {
                /* Rule 7: Prefer public address
                 * Note: prefer temporary address if use_tempaddr >= 2
                 */
                int preftmp = dst->prefs & (IPV6_PREFER_SRC_PUBLIC|IPV6_PREFER_SRC_TMP) ?
                                !!(dst->prefs & IPV6_PREFER_SRC_TMP) :
                                READ_ONCE(score->ifa->idev->cnf.use_tempaddr) >= 2;
                ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ preftmp;
                break;
            }
        case IPV6_SADDR_RULE_ORCHID:
                /* Rule 8-: Prefer ORCHID vs ORCHID or
                 *          non-ORCHID vs non-ORCHID
                 */
                ret = !(ipv6_addr_orchid(&score->ifa->addr) ^
                        ipv6_addr_orchid(dst->addr));
                break;
        case IPV6_SADDR_RULE_PREFIX:
                /* Rule 8: Use longest matching prefix */
                ret = ipv6_addr_diff(&score->ifa->addr, dst->addr);
                if (ret > score->ifa->prefix_len)
                        ret = score->ifa->prefix_len;
                score->matchlen = ret;
                break;
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        case IPV6_SADDR_RULE_NOT_OPTIMISTIC:
                /* Optimistic addresses still have lower precedence than other
                 * preferred addresses.
                 */
                ret = !(score->ifa->flags & IFA_F_OPTIMISTIC);
                break;
#endif
        default:
                ret = 0;
        }

        if (ret)
                __set_bit(i, score->scorebits);
        score->rule = i;
out:
        return ret;
}

static int __ipv6_dev_get_saddr(struct net *net,
                                struct ipv6_saddr_dst *dst,
                                struct inet6_dev *idev,
                                struct ipv6_saddr_score *scores,
                                int hiscore_idx)
{
        struct ipv6_saddr_score *score = &scores[1 - hiscore_idx], *hiscore = &scores[hiscore_idx];

        list_for_each_entry_rcu(score->ifa, &idev->addr_list, if_list) {
                int i;

                /*
                 * - Tentative Address (RFC2462 section 5.4)
                 *  - A tentative address is not considered
                 *    "assigned to an interface" in the traditional
                 *    sense, unless it is also flagged as optimistic.
                 * - Candidate Source Address (section 4)
                 *  - In any case, anycast addresses, multicast
                 *    addresses, and the unspecified address MUST
                 *    NOT be included in a candidate set.
                 */
                if ((score->ifa->flags & IFA_F_TENTATIVE) &&
                    (!(score->ifa->flags & IFA_F_OPTIMISTIC)))
                        continue;

                score->addr_type = __ipv6_addr_type(&score->ifa->addr);

                if (unlikely(score->addr_type == IPV6_ADDR_ANY ||
                             score->addr_type & IPV6_ADDR_MULTICAST)) {
                        net_dbg_ratelimited("ADDRCONF: unspecified / multicast address assigned as unicast address on %s",
                                            idev->dev->name);
                        continue;
                }

                score->rule = -1;
                bitmap_zero(score->scorebits, IPV6_SADDR_RULE_MAX);

                for (i = 0; i < IPV6_SADDR_RULE_MAX; i++) {
                        int minihiscore, miniscore;

                        minihiscore = ipv6_get_saddr_eval(net, hiscore, dst, i);
                        miniscore = ipv6_get_saddr_eval(net, score, dst, i);

                        if (minihiscore > miniscore) {
                                if (i == IPV6_SADDR_RULE_SCOPE &&
                                    score->scopedist > 0) {
                                        /*
                                         * special case:
                                         * each remaining entry
                                         * has too small (not enough)
                                         * scope, because ifa entries
                                         * are sorted by their scope
                                         * values.
                                         */
                                        goto out;
                                }
                                break;
                        } else if (minihiscore < miniscore) {
                                swap(hiscore, score);
                                hiscore_idx = 1 - hiscore_idx;

                                /* restore our iterator */
                                score->ifa = hiscore->ifa;

                                break;
                        }
                }
        }
out:
        return hiscore_idx;
}

static int ipv6_get_saddr_master(struct net *net,
                                 const struct net_device *dst_dev,
                                 const struct net_device *master,
                                 struct ipv6_saddr_dst *dst,
                                 struct ipv6_saddr_score *scores,
                                 int hiscore_idx)
{
        struct inet6_dev *idev;

        idev = __in6_dev_get(dst_dev);
        if (idev)
                hiscore_idx = __ipv6_dev_get_saddr(net, dst, idev,
                                                   scores, hiscore_idx);

        idev = __in6_dev_get(master);
        if (idev)
                hiscore_idx = __ipv6_dev_get_saddr(net, dst, idev,
                                                   scores, hiscore_idx);

        return hiscore_idx;
}

int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
                       const struct in6_addr *daddr, unsigned int prefs,
                       struct in6_addr *saddr)
{
        struct ipv6_saddr_score scores[2], *hiscore;
        struct ipv6_saddr_dst dst;
        struct inet6_dev *idev;
        struct net_device *dev;
        int dst_type;
        bool use_oif_addr = false;
        int hiscore_idx = 0;
        int ret = 0;

        dst_type = __ipv6_addr_type(daddr);
        dst.addr = daddr;
        dst.ifindex = dst_dev ? dst_dev->ifindex : 0;
        dst.scope = __ipv6_addr_src_scope(dst_type);
        dst.label = ipv6_addr_label(net, daddr, dst_type, dst.ifindex);
        dst.prefs = prefs;

        scores[hiscore_idx].rule = -1;
        scores[hiscore_idx].ifa = NULL;

        rcu_read_lock();

        /* Candidate Source Address (section 4)
         *  - multicast and link-local destination address,
         *    the set of candidate source address MUST only
         *    include addresses assigned to interfaces
         *    belonging to the same link as the outgoing
         *    interface.
         * (- For site-local destination addresses, the
         *    set of candidate source addresses MUST only
         *    include addresses assigned to interfaces
         *    belonging to the same site as the outgoing
         *    interface.)
         *  - "It is RECOMMENDED that the candidate source addresses
         *    be the set of unicast addresses assigned to the
         *    interface that will be used to send to the destination
         *    (the 'outgoing' interface)." (RFC 6724)
         */
        if (dst_dev) {
                idev = __in6_dev_get(dst_dev);
                if ((dst_type & IPV6_ADDR_MULTICAST) ||
                    dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
                    (idev && READ_ONCE(idev->cnf.use_oif_addrs_only))) {
                        use_oif_addr = true;
                }
        }

        if (use_oif_addr) {
                if (idev)
                        hiscore_idx = __ipv6_dev_get_saddr(net, &dst, idev, scores, hiscore_idx);
        } else {
                const struct net_device *master;
                int master_idx = 0;

                /* if dst_dev exists and is enslaved to an L3 device, then
                 * prefer addresses from dst_dev and then the master over
                 * any other enslaved devices in the L3 domain.
                 */
                master = l3mdev_master_dev_rcu(dst_dev);
                if (master) {
                        master_idx = master->ifindex;

                        hiscore_idx = ipv6_get_saddr_master(net, dst_dev,
                                                            master, &dst,
                                                            scores, hiscore_idx);

                        if (scores[hiscore_idx].ifa &&
                            scores[hiscore_idx].scopedist >= 0)
                                goto out;
                }

                for_each_netdev_rcu(net, dev) {
                        /* only consider addresses on devices in the
                         * same L3 domain
                         */
                        if (l3mdev_master_ifindex_rcu(dev) != master_idx)
                                continue;
                        idev = __in6_dev_get(dev);
                        if (!idev)
                                continue;
                        hiscore_idx = __ipv6_dev_get_saddr(net, &dst, idev, scores, hiscore_idx);
                }
        }

out:
        hiscore = &scores[hiscore_idx];
        if (!hiscore->ifa)
                ret = -EADDRNOTAVAIL;
        else
                *saddr = hiscore->ifa->addr;

        rcu_read_unlock();
        return ret;
}
EXPORT_SYMBOL(ipv6_dev_get_saddr);

static int __ipv6_get_lladdr(struct inet6_dev *idev, struct in6_addr *addr,
                              u32 banned_flags)
{
        struct inet6_ifaddr *ifp;
        int err = -EADDRNOTAVAIL;

        list_for_each_entry_reverse(ifp, &idev->addr_list, if_list) {
                if (ifp->scope > IFA_LINK)
                        break;
                if (ifp->scope == IFA_LINK &&
                    !(ifp->flags & banned_flags)) {
                        *addr = ifp->addr;
                        err = 0;
                        break;
                }
        }
        return err;
}

int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
                    u32 banned_flags)
{
        struct inet6_dev *idev;
        int err = -EADDRNOTAVAIL;

        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                read_lock_bh(&idev->lock);
                err = __ipv6_get_lladdr(idev, addr, banned_flags);
                read_unlock_bh(&idev->lock);
        }
        rcu_read_unlock();
        return err;
}

static int ipv6_count_addresses(const struct inet6_dev *idev)
{
        const struct inet6_ifaddr *ifp;
        int cnt = 0;

        rcu_read_lock();
        list_for_each_entry_rcu(ifp, &idev->addr_list, if_list)
                cnt++;
        rcu_read_unlock();
        return cnt;
}

int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
                  const struct net_device *dev, int strict)
{
        return ipv6_chk_addr_and_flags(net, addr, dev, !dev,
                                       strict, IFA_F_TENTATIVE);
}
EXPORT_SYMBOL(ipv6_chk_addr);

/* device argument is used to find the L3 domain of interest. If
 * skip_dev_check is set, then the ifp device is not checked against
 * the passed in dev argument. So the 2 cases for addresses checks are:
 *   1. does the address exist in the L3 domain that dev is part of
 *      (skip_dev_check = true), or
 *
 *   2. does the address exist on the specific device
 *      (skip_dev_check = false)
 */
static struct net_device *
__ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
                          const struct net_device *dev, bool skip_dev_check,
                          int strict, u32 banned_flags)
{
        unsigned int hash = inet6_addr_hash(net, addr);
        struct net_device *l3mdev, *ndev;
        struct inet6_ifaddr *ifp;
        u32 ifp_flags;

        rcu_read_lock();

        l3mdev = l3mdev_master_dev_rcu(dev);
        if (skip_dev_check)
                dev = NULL;

        hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
                ndev = ifp->idev->dev;

                if (l3mdev_master_dev_rcu(ndev) != l3mdev)
                        continue;

                /* Decouple optimistic from tentative for evaluation here.
                 * Ban optimistic addresses explicitly, when required.
                 */
                ifp_flags = (ifp->flags&IFA_F_OPTIMISTIC)
                            ? (ifp->flags&~IFA_F_TENTATIVE)
                            : ifp->flags;
                if (ipv6_addr_equal(&ifp->addr, addr) &&
                    !(ifp_flags&banned_flags) &&
                    (!dev || ndev == dev ||
                     !(ifp->scope&(IFA_LINK|IFA_HOST) || strict))) {
                        rcu_read_unlock();
                        return ndev;
                }
        }

        rcu_read_unlock();
        return NULL;
}

int ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
                            const struct net_device *dev, bool skip_dev_check,
                            int strict, u32 banned_flags)
{
        return __ipv6_chk_addr_and_flags(net, addr, dev, skip_dev_check,
                                         strict, banned_flags) ? 1 : 0;
}
EXPORT_SYMBOL(ipv6_chk_addr_and_flags);


/* Compares an address/prefix_len with addresses on device @dev.
 * If one is found it returns true.
 */
bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
        const unsigned int prefix_len, struct net_device *dev)
{
        const struct inet6_ifaddr *ifa;
        const struct inet6_dev *idev;
        bool ret = false;

        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
                        ret = ipv6_prefix_equal(addr, &ifa->addr, prefix_len);
                        if (ret)
                                break;
                }
        }
        rcu_read_unlock();

        return ret;
}
EXPORT_SYMBOL(ipv6_chk_custom_prefix);

int ipv6_chk_prefix(const struct in6_addr *addr, struct net_device *dev)
{
        const struct inet6_ifaddr *ifa;
        const struct inet6_dev *idev;
        int     onlink;

        onlink = 0;
        rcu_read_lock();
        idev = __in6_dev_get(dev);
        if (idev) {
                list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
                        onlink = ipv6_prefix_equal(addr, &ifa->addr,
                                                   ifa->prefix_len);
                        if (onlink)
                                break;
                }
        }
        rcu_read_unlock();
        return onlink;
}
EXPORT_SYMBOL(ipv6_chk_prefix);

/**
 * ipv6_dev_find - find the first device with a given source address.
 * @net: the net namespace
 * @addr: the source address
 * @dev: used to find the L3 domain of interest
 *
 * The caller should be protected by RCU, or RTNL.
 */
struct net_device *ipv6_dev_find(struct net *net, const struct in6_addr *addr,
                                 struct net_device *dev)
{
        return __ipv6_chk_addr_and_flags(net, addr, dev, !dev, 1,
                                         IFA_F_TENTATIVE);
}
EXPORT_SYMBOL(ipv6_dev_find);

struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *addr,
                                     struct net_device *dev, int strict)
{
        unsigned int hash = inet6_addr_hash(net, addr);
        struct inet6_ifaddr *ifp, *result = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
                if (ipv6_addr_equal(&ifp->addr, addr)) {
                        if (!dev || ifp->idev->dev == dev ||
                            !(ifp->scope&(IFA_LINK|IFA_HOST) || strict)) {
                                if (in6_ifa_hold_safe(ifp)) {
                                        result = ifp;
                                        break;
                                }
                        }
                }
        }
        rcu_read_unlock();

        return result;
}

/* Gets referenced address, destroys ifaddr */

static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
{
        if (dad_failed)
                ifp->flags |= IFA_F_DADFAILED;

        if (ifp->flags&IFA_F_TEMPORARY) {
                struct inet6_ifaddr *ifpub;
                spin_lock_bh(&ifp->lock);
                ifpub = ifp->ifpub;
                if (ifpub) {
                        in6_ifa_hold(ifpub);
                        spin_unlock_bh(&ifp->lock);
                        ipv6_create_tempaddr(ifpub, true);
                        in6_ifa_put(ifpub);
                } else {
                        spin_unlock_bh(&ifp->lock);
                }
                ipv6_del_addr(ifp);
        } else if (ifp->flags&IFA_F_PERMANENT || !dad_failed) {
                spin_lock_bh(&ifp->lock);
                addrconf_del_dad_work(ifp);
                ifp->flags |= IFA_F_TENTATIVE;
                if (dad_failed)
                        ifp->flags &= ~IFA_F_OPTIMISTIC;
                spin_unlock_bh(&ifp->lock);
                if (dad_failed)
                        ipv6_ifa_notify(0, ifp);
                in6_ifa_put(ifp);
        } else {
                ipv6_del_addr(ifp);
        }
}

static int addrconf_dad_end(struct inet6_ifaddr *ifp)
{
        int err = -ENOENT;

        spin_lock_bh(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_DAD) {
                ifp->state = INET6_IFADDR_STATE_POSTDAD;
                err = 0;
        }
        spin_unlock_bh(&ifp->lock);

        return err;
}

void addrconf_dad_failure(struct sk_buff *skb, struct inet6_ifaddr *ifp)
{
        struct inet6_dev *idev = ifp->idev;
        struct net *net = dev_net(idev->dev);
        int max_addresses;

        if (addrconf_dad_end(ifp)) {
                in6_ifa_put(ifp);
                return;
        }

        net_info_ratelimited("%s: IPv6 duplicate address %pI6c used by %pM detected!\n",
                             ifp->idev->dev->name, &ifp->addr, eth_hdr(skb)->h_source);

        spin_lock_bh(&ifp->lock);

        if (ifp->flags & IFA_F_STABLE_PRIVACY) {
                struct in6_addr new_addr;
                struct inet6_ifaddr *ifp2;
                int retries = ifp->stable_privacy_retry + 1;
                struct ifa6_config cfg = {
                        .pfx = &new_addr,
                        .plen = ifp->prefix_len,
                        .ifa_flags = ifp->flags,
                        .valid_lft = ifp->valid_lft,
                        .preferred_lft = ifp->prefered_lft,
                        .scope = ifp->scope,
                };

                if (retries > net->ipv6.sysctl.idgen_retries) {
                        net_info_ratelimited("%s: privacy stable address generation failed because of DAD conflicts!\n",
                                             ifp->idev->dev->name);
                        goto errdad;
                }

                new_addr = ifp->addr;
                if (ipv6_generate_stable_address(&new_addr, retries,
                                                 idev))
                        goto errdad;

                spin_unlock_bh(&ifp->lock);

                max_addresses = READ_ONCE(idev->cnf.max_addresses);
                if (max_addresses &&
                    ipv6_count_addresses(idev) >= max_addresses)
                        goto lock_errdad;

                net_info_ratelimited("%s: generating new stable privacy address because of DAD conflict\n",
                                     ifp->idev->dev->name);

                ifp2 = ipv6_add_addr(idev, &cfg, false, NULL);
                if (IS_ERR(ifp2))
                        goto lock_errdad;

                spin_lock_bh(&ifp2->lock);
                ifp2->stable_privacy_retry = retries;
                ifp2->state = INET6_IFADDR_STATE_PREDAD;
                spin_unlock_bh(&ifp2->lock);

                addrconf_mod_dad_work(ifp2, net->ipv6.sysctl.idgen_delay);
                in6_ifa_put(ifp2);
lock_errdad:
                spin_lock_bh(&ifp->lock);
        }

errdad:
        /* transition from _POSTDAD to _ERRDAD */
        ifp->state = INET6_IFADDR_STATE_ERRDAD;
        spin_unlock_bh(&ifp->lock);

        addrconf_mod_dad_work(ifp, 0);
        in6_ifa_put(ifp);
}

/* Join to solicited addr multicast group. */
void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr)
{
        struct in6_addr maddr;

        if (READ_ONCE(dev->flags) & (IFF_LOOPBACK | IFF_NOARP))
                return;

        addrconf_addr_solict_mult(addr, &maddr);
        ipv6_dev_mc_inc(dev, &maddr);
}

void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
{
        struct in6_addr maddr;

        if (READ_ONCE(idev->dev->flags) & (IFF_LOOPBACK | IFF_NOARP))
                return;

        addrconf_addr_solict_mult(addr, &maddr);
        __ipv6_dev_mc_dec(idev, &maddr);
}

static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
{
        struct in6_addr addr;

        if (ifp->prefix_len >= 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))
                return;
        __ipv6_dev_ac_inc(ifp->idev, &addr);
}

static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
{
        struct in6_addr addr;

        if (ifp->prefix_len >= 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))
                return;
        __ipv6_dev_ac_dec(ifp->idev, &addr);
}

static int addrconf_ifid_6lowpan(u8 *eui, struct net_device *dev)
{
        switch (dev->addr_len) {
        case ETH_ALEN:
                memcpy(eui, dev->dev_addr, 3);
                eui[3] = 0xFF;
                eui[4] = 0xFE;
                memcpy(eui + 5, dev->dev_addr + 3, 3);
                break;
        case EUI64_ADDR_LEN:
                memcpy(eui, dev->dev_addr, EUI64_ADDR_LEN);
                eui[0] ^= 2;
                break;
        default:
                return -1;
        }

        return 0;
}

static int addrconf_ifid_ieee1394(u8 *eui, struct net_device *dev)
{
        const union fwnet_hwaddr *ha;

        if (dev->addr_len != FWNET_ALEN)
                return -1;

        ha = (const union fwnet_hwaddr *)dev->dev_addr;

        memcpy(eui, &ha->uc.uniq_id, sizeof(ha->uc.uniq_id));
        eui[0] ^= 2;
        return 0;
}

static int addrconf_ifid_arcnet(u8 *eui, struct net_device *dev)
{
        /* XXX: inherit EUI-64 from other interface -- yoshfuji */
        if (dev->addr_len != ARCNET_ALEN)
                return -1;
        memset(eui, 0, 7);
        eui[7] = *(u8 *)dev->dev_addr;
        return 0;
}

static int addrconf_ifid_infiniband(u8 *eui, struct net_device *dev)
{
        if (dev->addr_len != INFINIBAND_ALEN)
                return -1;
        memcpy(eui, dev->dev_addr + 12, 8);
        eui[0] |= 2;
        return 0;
}

static int __ipv6_isatap_ifid(u8 *eui, __be32 addr)
{
        if (addr == 0)
                return -1;
        eui[0] = (ipv4_is_zeronet(addr) || ipv4_is_private_10(addr) ||
                  ipv4_is_loopback(addr) || ipv4_is_linklocal_169(addr) ||
                  ipv4_is_private_172(addr) || ipv4_is_test_192(addr) ||
                  ipv4_is_anycast_6to4(addr) || ipv4_is_private_192(addr) ||
                  ipv4_is_test_198(addr) || ipv4_is_multicast(addr) ||
                  ipv4_is_lbcast(addr)) ? 0x00 : 0x02;
        eui[1] = 0;
        eui[2] = 0x5E;
        eui[3] = 0xFE;
        memcpy(eui + 4, &addr, 4);
        return 0;
}

static int addrconf_ifid_sit(u8 *eui, struct net_device *dev)
{
        if (dev->priv_flags & IFF_ISATAP)
                return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
        return -1;
}

static int addrconf_ifid_gre(u8 *eui, struct net_device *dev)
{
        return __ipv6_isatap_ifid(eui, *(__be32 *)dev->dev_addr);
}

static int addrconf_ifid_ip6tnl(u8 *eui, struct net_device *dev)
{
        memcpy(eui, dev->perm_addr, 3);
        memcpy(eui + 5, dev->perm_addr + 3, 3);
        eui[3] = 0xFF;
        eui[4] = 0xFE;
        eui[0] ^= 2;
        return 0;
}

static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
{
        switch (dev->type) {
        case ARPHRD_ETHER:
        case ARPHRD_FDDI:
                return addrconf_ifid_eui48(eui, dev);
        case ARPHRD_ARCNET:
                return addrconf_ifid_arcnet(eui, dev);
        case ARPHRD_INFINIBAND:
                return addrconf_ifid_infiniband(eui, dev);
        case ARPHRD_SIT:
                return addrconf_ifid_sit(eui, dev);
        case ARPHRD_IPGRE:
        case ARPHRD_TUNNEL:
                return addrconf_ifid_gre(eui, dev);
        case ARPHRD_6LOWPAN:
                return addrconf_ifid_6lowpan(eui, dev);
        case ARPHRD_IEEE1394:
                return addrconf_ifid_ieee1394(eui, dev);
        case ARPHRD_TUNNEL6:
        case ARPHRD_IP6GRE:
        case ARPHRD_RAWIP:
                return addrconf_ifid_ip6tnl(eui, dev);
        }
        return -1;
}

static int ipv6_inherit_eui64(u8 *eui, struct inet6_dev *idev)
{
        int err = -1;
        struct inet6_ifaddr *ifp;

        read_lock_bh(&idev->lock);
        list_for_each_entry_reverse(ifp, &idev->addr_list, if_list) {
                if (ifp->scope > IFA_LINK)
                        break;
                if (ifp->scope == IFA_LINK && !(ifp->flags&IFA_F_TENTATIVE)) {
                        memcpy(eui, ifp->addr.s6_addr+8, 8);
                        err = 0;
                        break;
                }
        }
        read_unlock_bh(&idev->lock);
        return err;
}

/* Generation of a randomized Interface Identifier
 * draft-ietf-6man-rfc4941bis, Section 3.3.1
 */

static void ipv6_gen_rnd_iid(struct in6_addr *addr)
{
regen:
        get_random_bytes(&addr->s6_addr[8], 8);

        /* <draft-ietf-6man-rfc4941bis-08.txt>, Section 3.3.1:
         * check if generated address is not inappropriate:
         *
         * - Reserved IPv6 Interface Identifiers
         * - XXX: already assigned to an address on the device
         */

        /* Subnet-router anycast: 0000:0000:0000:0000 */
        if (!(addr->s6_addr32[2] | addr->s6_addr32[3]))
                goto regen;

        /* IANA Ethernet block: 0200:5EFF:FE00:0000-0200:5EFF:FE00:5212
         * Proxy Mobile IPv6:   0200:5EFF:FE00:5213
         * IANA Ethernet block: 0200:5EFF:FE00:5214-0200:5EFF:FEFF:FFFF
         */
        if (ntohl(addr->s6_addr32[2]) == 0x02005eff &&
            (ntohl(addr->s6_addr32[3]) & 0Xff000000) == 0xfe000000)
                goto regen;

        /* Reserved subnet anycast addresses */
        if (ntohl(addr->s6_addr32[2]) == 0xfdffffff &&
            ntohl(addr->s6_addr32[3]) >= 0Xffffff80)
                goto regen;
}

/*
 *      Add prefix route.
 */

static void
addrconf_prefix_route(struct in6_addr *pfx, int plen, u32 metric,
                      struct net_device *dev, unsigned long expires,
                      u32 flags, gfp_t gfp_flags)
{
        struct fib6_config cfg = {
                .fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_PREFIX,
                .fc_metric = metric ? : IP6_RT_PRIO_ADDRCONF,
                .fc_ifindex = dev->ifindex,
                .fc_expires = expires,
                .fc_dst_len = plen,
                .fc_flags = RTF_UP | flags,
                .fc_nlinfo.nl_net = dev_net(dev),
                .fc_protocol = RTPROT_KERNEL,
                .fc_type = RTN_UNICAST,
        };

        cfg.fc_dst = *pfx;

        /* Prevent useless cloning on PtP SIT.
           This thing is done here expecting that the whole
           class of non-broadcast devices need not cloning.
         */
#if IS_ENABLED(CONFIG_IPV6_SIT)
        if (dev->type == ARPHRD_SIT && (dev->flags & IFF_POINTOPOINT))
                cfg.fc_flags |= RTF_NONEXTHOP;
#endif

        ip6_route_add(&cfg, gfp_flags, NULL);
}


static struct fib6_info *addrconf_get_prefix_route(const struct in6_addr *pfx,
                                                  int plen,
                                                  const struct net_device *dev,
                                                  u32 flags, u32 noflags,
                                                  bool no_gw)
{
        struct fib6_node *fn;
        struct fib6_info *rt = NULL;
        struct fib6_table *table;
        u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_PREFIX;

        table = fib6_get_table(dev_net(dev), tb_id);
        if (!table)
                return NULL;

        rcu_read_lock();
        fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0, true);
        if (!fn)
                goto out;

        for_each_fib6_node_rt_rcu(fn) {
                /* prefix routes only use builtin fib6_nh */
                if (rt->nh)
                        continue;

                if (rt->fib6_nh->fib_nh_dev->ifindex != dev->ifindex)
                        continue;
                if (no_gw && rt->fib6_nh->fib_nh_gw_family)
                        continue;
                if ((rt->fib6_flags & flags) != flags)
                        continue;
                if ((rt->fib6_flags & noflags) != 0)
                        continue;
                if (!fib6_info_hold_safe(rt))
                        continue;
                break;
        }
out:
        rcu_read_unlock();
        return rt;
}


/* Create "default" multicast route to the interface */

static void addrconf_add_mroute(struct net_device *dev)
{
        struct fib6_config cfg = {
                .fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_LOCAL,
                .fc_metric = IP6_RT_PRIO_ADDRCONF,
                .fc_ifindex = dev->ifindex,
                .fc_dst_len = 8,
                .fc_flags = RTF_UP,
                .fc_type = RTN_MULTICAST,
                .fc_nlinfo.nl_net = dev_net(dev),
                .fc_protocol = RTPROT_KERNEL,
        };

        ipv6_addr_set(&cfg.fc_dst, htonl(0xFF000000), 0, 0, 0);

        ip6_route_add(&cfg, GFP_KERNEL, NULL);
}

static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = ipv6_find_idev(dev);
        if (IS_ERR(idev))
                return idev;

        if (idev->cnf.disable_ipv6)
                return ERR_PTR(-EACCES);

        /* Add default multicast route */
        if (!(dev->flags & IFF_LOOPBACK) && !netif_is_l3_master(dev))
                addrconf_add_mroute(dev);

        return idev;
}

static void delete_tempaddrs(struct inet6_dev *idev,
                             struct inet6_ifaddr *ifp)
{
        struct inet6_ifaddr *ift, *tmp;

        write_lock_bh(&idev->lock);
        list_for_each_entry_safe(ift, tmp, &idev->tempaddr_list, tmp_list) {
                if (ift->ifpub != ifp)
                        continue;

                in6_ifa_hold(ift);
                write_unlock_bh(&idev->lock);
                ipv6_del_addr(ift);
                write_lock_bh(&idev->lock);
        }
        write_unlock_bh(&idev->lock);
}

static void manage_tempaddrs(struct inet6_dev *idev,
                             struct inet6_ifaddr *ifp,
                             __u32 valid_lft, __u32 prefered_lft,
                             bool create, unsigned long now)
{
        u32 flags;
        struct inet6_ifaddr *ift;

        read_lock_bh(&idev->lock);
        /* update all temporary addresses in the list */
        list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
                int age, max_valid, max_prefered;

                if (ifp != ift->ifpub)
                        continue;

                /* RFC 4941 section 3.3:
                 * If a received option will extend the lifetime of a public
                 * address, the lifetimes of temporary addresses should
                 * be extended, subject to the overall constraint that no
                 * temporary addresses should ever remain "valid" or "preferred"
                 * for a time longer than (TEMP_VALID_LIFETIME) or
                 * (TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR), respectively.
                 */
                age = (now - ift->cstamp) / HZ;
                max_valid = READ_ONCE(idev->cnf.temp_valid_lft) - age;
                if (max_valid < 0)
                        max_valid = 0;

                max_prefered = READ_ONCE(idev->cnf.temp_prefered_lft) -
                               idev->desync_factor - age;
                if (max_prefered < 0)
                        max_prefered = 0;

                if (valid_lft > max_valid)
                        valid_lft = max_valid;

                if (prefered_lft > max_prefered)
                        prefered_lft = max_prefered;

                spin_lock(&ift->lock);
                flags = ift->flags;
                ift->valid_lft = valid_lft;
                ift->prefered_lft = prefered_lft;
                ift->tstamp = now;
                if (prefered_lft > 0)
                        ift->flags &= ~IFA_F_DEPRECATED;

                spin_unlock(&ift->lock);
                if (!(flags&IFA_F_TENTATIVE))
                        ipv6_ifa_notify(0, ift);
        }

        /* Also create a temporary address if it's enabled but no temporary
         * address currently exists.
         * However, we get called with valid_lft == 0, prefered_lft == 0, create == false
         * as part of cleanup (ie. deleting the mngtmpaddr).
         * We don't want that to result in creating a new temporary ip address.
         */
        if (list_empty(&idev->tempaddr_list) && (valid_lft || prefered_lft))
                create = true;

        if (create && READ_ONCE(idev->cnf.use_tempaddr) > 0) {
                /* When a new public address is created as described
                 * in [ADDRCONF], also create a new temporary address.
                 */
                read_unlock_bh(&idev->lock);
                ipv6_create_tempaddr(ifp, false);
        } else {
                read_unlock_bh(&idev->lock);
        }
}

static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
{
        return idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY ||
               idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
}

int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
                                 const struct prefix_info *pinfo,
                                 struct inet6_dev *in6_dev,
                                 const struct in6_addr *addr, int addr_type,
                                 u32 addr_flags, bool sllao, bool tokenized,
                                 __u32 valid_lft, u32 prefered_lft)
{
        struct inet6_ifaddr *ifp = ipv6_get_ifaddr(net, addr, dev, 1);
        int create = 0, update_lft = 0;

        if (!ifp && valid_lft) {
                int max_addresses = READ_ONCE(in6_dev->cnf.max_addresses);
                struct ifa6_config cfg = {
                        .pfx = addr,
                        .plen = pinfo->prefix_len,
                        .ifa_flags = addr_flags,
                        .valid_lft = valid_lft,
                        .preferred_lft = prefered_lft,
                        .scope = addr_type & IPV6_ADDR_SCOPE_MASK,
                        .ifa_proto = IFAPROT_KERNEL_RA
                };

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
                if ((READ_ONCE(net->ipv6.devconf_all->optimistic_dad) ||
                     READ_ONCE(in6_dev->cnf.optimistic_dad)) &&
                    !net->ipv6.devconf_all->forwarding && sllao)
                        cfg.ifa_flags |= IFA_F_OPTIMISTIC;
#endif

                /* Do not allow to create too much of autoconfigured
                 * addresses; this would be too easy way to crash kernel.
                 */
                if (!max_addresses ||
                    ipv6_count_addresses(in6_dev) < max_addresses)
                        ifp = ipv6_add_addr(in6_dev, &cfg, false, NULL);

                if (IS_ERR_OR_NULL(ifp))
                        return -1;

                create = 1;
                spin_lock_bh(&ifp->lock);
                ifp->flags |= IFA_F_MANAGETEMPADDR;
                ifp->cstamp = jiffies;
                ifp->tokenized = tokenized;
                spin_unlock_bh(&ifp->lock);
                addrconf_dad_start(ifp);
        }

        if (ifp) {
                u32 flags;
                unsigned long now;
                u32 stored_lft;

                /* update lifetime (RFC2462 5.5.3 e) */
                spin_lock_bh(&ifp->lock);
                now = jiffies;
                if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
                        stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
                else
                        stored_lft = 0;

                /* RFC4862 Section 5.5.3e:
                 * "Note that the preferred lifetime of the
                 *  corresponding address is always reset to
                 *  the Preferred Lifetime in the received
                 *  Prefix Information option, regardless of
                 *  whether the valid lifetime is also reset or
                 *  ignored."
                 *
                 * So we should always update prefered_lft here.
                 */
                update_lft = !create && stored_lft;

                if (update_lft && !READ_ONCE(in6_dev->cnf.ra_honor_pio_life)) {
                        const u32 minimum_lft = min_t(u32,
                                stored_lft, MIN_VALID_LIFETIME);
                        valid_lft = max(valid_lft, minimum_lft);
                }

                if (update_lft) {
                        ifp->valid_lft = valid_lft;
                        ifp->prefered_lft = prefered_lft;
                        WRITE_ONCE(ifp->tstamp, now);
                        flags = ifp->flags;
                        ifp->flags &= ~IFA_F_DEPRECATED;
                        spin_unlock_bh(&ifp->lock);

                        if (!(flags&IFA_F_TENTATIVE))
                                ipv6_ifa_notify(0, ifp);
                } else
                        spin_unlock_bh(&ifp->lock);

                manage_tempaddrs(in6_dev, ifp, valid_lft, prefered_lft,
                                 create, now);

                in6_ifa_put(ifp);
                addrconf_verify(net);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(addrconf_prefix_rcv_add_addr);

void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
{
        struct prefix_info *pinfo;
        struct fib6_table *table;
        __u32 valid_lft;
        __u32 prefered_lft;
        int addr_type, err;
        u32 addr_flags = 0;
        struct inet6_dev *in6_dev;
        struct net *net = dev_net(dev);
        bool ignore_autoconf = false;

        pinfo = (struct prefix_info *) opt;

        if (len < sizeof(struct prefix_info)) {
                netdev_dbg(dev, "addrconf: prefix option too short\n");
                return;
        }

        /*
         *      Validation checks ([ADDRCONF], page 19)
         */

        addr_type = ipv6_addr_type(&pinfo->prefix);

        if (addr_type & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL))
                return;

        valid_lft = ntohl(pinfo->valid);
        prefered_lft = ntohl(pinfo->prefered);

        if (prefered_lft > valid_lft) {
                net_warn_ratelimited("addrconf: prefix option has invalid lifetime\n");
                return;
        }

        in6_dev = in6_dev_get(dev);

        if (!in6_dev) {
                net_dbg_ratelimited("addrconf: device %s not configured\n",
                                    dev->name);
                return;
        }

        if (valid_lft != 0 && valid_lft < in6_dev->cnf.accept_ra_min_lft)
                goto put;

        /*
         *      Two things going on here:
         *      1) Add routes for on-link prefixes
         *      2) Configure prefixes with the auto flag set
         */

        if (pinfo->onlink) {
                struct fib6_info *rt;
                unsigned long rt_expires;

                /* Avoid arithmetic overflow. Really, we could
                 * save rt_expires in seconds, likely valid_lft,
                 * but it would require division in fib gc, that it
                 * not good.
                 */
                if (HZ > USER_HZ)
                        rt_expires = addrconf_timeout_fixup(valid_lft, HZ);
                else
                        rt_expires = addrconf_timeout_fixup(valid_lft, USER_HZ);

                if (addrconf_finite_timeout(rt_expires))
                        rt_expires *= HZ;

                rt = addrconf_get_prefix_route(&pinfo->prefix,
                                               pinfo->prefix_len,
                                               dev,
                                               RTF_ADDRCONF | RTF_PREFIX_RT,
                                               RTF_DEFAULT, true);

                if (rt) {
                        /* Autoconf prefix route */
                        if (valid_lft == 0) {
                                ip6_del_rt(net, rt, false);
                                rt = NULL;
                        } else {
                                table = rt->fib6_table;
                                spin_lock_bh(&table->tb6_lock);

                                if (addrconf_finite_timeout(rt_expires)) {
                                        /* not infinity */
                                        fib6_set_expires(rt, jiffies + rt_expires);
                                        fib6_add_gc_list(rt);
                                } else {
                                        fib6_clean_expires(rt);
                                        fib6_may_remove_gc_list(net, rt);
                                }

                                spin_unlock_bh(&table->tb6_lock);
                        }
                } else if (valid_lft) {
                        clock_t expires = 0;
                        int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
                        if (addrconf_finite_timeout(rt_expires)) {
                                /* not infinity */
                                flags |= RTF_EXPIRES;
                                expires = jiffies_to_clock_t(rt_expires);
                        }
                        addrconf_prefix_route(&pinfo->prefix, pinfo->prefix_len,
                                              0, dev, expires, flags,
                                              GFP_ATOMIC);
                }
                fib6_info_release(rt);
        }

        /* Try to figure out our local address for this prefix */

        ignore_autoconf = READ_ONCE(in6_dev->cnf.ra_honor_pio_pflag) && pinfo->preferpd;
        if (pinfo->autoconf && in6_dev->cnf.autoconf && !ignore_autoconf) {
                struct in6_addr addr;
                bool tokenized = false, dev_addr_generated = false;

                if (pinfo->prefix_len == 64) {
                        memcpy(&addr, &pinfo->prefix, 8);

                        if (!ipv6_addr_any(&in6_dev->token)) {
                                read_lock_bh(&in6_dev->lock);
                                memcpy(addr.s6_addr + 8,
                                       in6_dev->token.s6_addr + 8, 8);
                                read_unlock_bh(&in6_dev->lock);
                                tokenized = true;
                        } else if (is_addr_mode_generate_stable(in6_dev) &&
                                   !ipv6_generate_stable_address(&addr, 0,
                                                                 in6_dev)) {
                                addr_flags |= IFA_F_STABLE_PRIVACY;
                                goto ok;
                        } else if (ipv6_generate_eui64(addr.s6_addr + 8, dev) &&
                                   ipv6_inherit_eui64(addr.s6_addr + 8, in6_dev)) {
                                goto put;
                        } else {
                                dev_addr_generated = true;
                        }
                        goto ok;
                }
                net_dbg_ratelimited("IPv6 addrconf: prefix with wrong length %d\n",
                                    pinfo->prefix_len);
                goto put;

ok:
                err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
                                                   &addr, addr_type,
                                                   addr_flags, sllao,
                                                   tokenized, valid_lft,
                                                   prefered_lft);
                if (err)
                        goto put;

                /* Ignore error case here because previous prefix add addr was
                 * successful which will be notified.
                 */
                ndisc_ops_prefix_rcv_add_addr(net, dev, pinfo, in6_dev, &addr,
                                              addr_type, addr_flags, sllao,
                                              tokenized, valid_lft,
                                              prefered_lft,
                                              dev_addr_generated);
        }
        inet6_prefix_notify(RTM_NEWPREFIX, in6_dev, pinfo);
put:
        in6_dev_put(in6_dev);
}

static int addrconf_set_sit_dstaddr(struct net *net, struct net_device *dev,
                struct in6_ifreq *ireq)
{
        struct ip_tunnel_parm_kern p = { };
        int err;

        if (!(ipv6_addr_type(&ireq->ifr6_addr) & IPV6_ADDR_COMPATv4))
                return -EADDRNOTAVAIL;

        p.iph.daddr = ireq->ifr6_addr.s6_addr32[3];
        p.iph.version = 4;
        p.iph.ihl = 5;
        p.iph.protocol = IPPROTO_IPV6;
        p.iph.ttl = 64;

        if (!dev->netdev_ops->ndo_tunnel_ctl)
                return -EOPNOTSUPP;
        err = dev->netdev_ops->ndo_tunnel_ctl(dev, &p, SIOCADDTUNNEL);
        if (err)
                return err;

        dev = __dev_get_by_name(net, p.name);
        if (!dev)
                return -ENOBUFS;
        return dev_open(dev, NULL);
}

/*
 *      Set destination address.
 *      Special case for SIT interfaces where we create a new "virtual"
 *      device.
 */
int addrconf_set_dstaddr(struct net *net, void __user *arg)
{
        struct net_device *dev;
        struct in6_ifreq ireq;
        int err = -ENODEV;

        if (!IS_ENABLED(CONFIG_IPV6_SIT))
                return -ENODEV;
        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                return -EFAULT;

        rtnl_net_lock(net);
        dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
        if (dev && dev->type == ARPHRD_SIT)
                err = addrconf_set_sit_dstaddr(net, dev, &ireq);
        rtnl_net_unlock(net);
        return err;
}

static int ipv6_mc_config(struct sock *sk, bool join,
                          const struct in6_addr *addr, int ifindex)
{
        int ret;

        ASSERT_RTNL();

        lock_sock(sk);
        if (join)
                ret = ipv6_sock_mc_join(sk, ifindex, addr);
        else
                ret = ipv6_sock_mc_drop(sk, ifindex, addr);
        release_sock(sk);

        return ret;
}

/*
 *      Manual configuration of address on an interface
 */
static int inet6_addr_add(struct net *net, struct net_device *dev,
                          struct ifa6_config *cfg, clock_t expires, u32 flags,
                          struct netlink_ext_ack *extack)
{
        struct inet6_ifaddr *ifp;
        struct inet6_dev *idev;

        ASSERT_RTNL_NET(net);

        if (cfg->plen > 128) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid prefix length");
                return -EINVAL;
        }

        if (cfg->ifa_flags & IFA_F_MANAGETEMPADDR && cfg->plen != 64) {
                NL_SET_ERR_MSG_MOD(extack, "address with \"mngtmpaddr\" flag must have a prefix length of 64");
                return -EINVAL;
        }

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev)) {
                NL_SET_ERR_MSG_MOD(extack, "IPv6 is disabled on this device");
                return PTR_ERR(idev);
        }

        if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
                int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
                                         true, cfg->pfx, dev->ifindex);

                if (ret < 0) {
                        NL_SET_ERR_MSG_MOD(extack, "Multicast auto join failed");
                        return ret;
                }
        }

        cfg->scope = ipv6_addr_scope(cfg->pfx);

        ifp = ipv6_add_addr(idev, cfg, true, extack);
        if (!IS_ERR(ifp)) {
                if (!(cfg->ifa_flags & IFA_F_NOPREFIXROUTE)) {
                        addrconf_prefix_route(&ifp->addr, ifp->prefix_len,
                                              ifp->rt_priority, dev, expires,
                                              flags, GFP_KERNEL);
                }

                /* Send a netlink notification if DAD is enabled and
                 * optimistic flag is not set
                 */
                if (!(ifp->flags & (IFA_F_OPTIMISTIC | IFA_F_NODAD)))
                        ipv6_ifa_notify(0, ifp);
                /*
                 * Note that section 3.1 of RFC 4429 indicates
                 * that the Optimistic flag should not be set for
                 * manually configured addresses
                 */
                addrconf_dad_start(ifp);
                if (cfg->ifa_flags & IFA_F_MANAGETEMPADDR)
                        manage_tempaddrs(idev, ifp, cfg->valid_lft,
                                         cfg->preferred_lft, true, jiffies);
                in6_ifa_put(ifp);
                addrconf_verify_rtnl(net);
                return 0;
        } else if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
                ipv6_mc_config(net->ipv6.mc_autojoin_sk, false,
                               cfg->pfx, dev->ifindex);
        }

        return PTR_ERR(ifp);
}

static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
                          const struct in6_addr *pfx, unsigned int plen,
                          struct netlink_ext_ack *extack)
{
        struct inet6_ifaddr *ifp;
        struct inet6_dev *idev;
        struct net_device *dev;

        if (plen > 128) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid prefix length");
                return -EINVAL;
        }

        dev = __dev_get_by_index(net, ifindex);
        if (!dev) {
                NL_SET_ERR_MSG_MOD(extack, "Unable to find the interface");
                return -ENODEV;
        }

        idev = __in6_dev_get_rtnl_net(dev);
        if (!idev) {
                NL_SET_ERR_MSG_MOD(extack, "IPv6 is disabled on this device");
                return -ENXIO;
        }

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                if (ifp->prefix_len == plen &&
                    ipv6_addr_equal(pfx, &ifp->addr)) {
                        in6_ifa_hold(ifp);
                        read_unlock_bh(&idev->lock);

                        if (!(ifp->flags & IFA_F_TEMPORARY) &&
                            (ifp->flags & IFA_F_MANAGETEMPADDR))
                                delete_tempaddrs(idev, ifp);

                        ipv6_del_addr(ifp);

                        addrconf_verify_rtnl(net);
                        if (ipv6_addr_is_multicast(pfx)) {
                                ipv6_mc_config(net->ipv6.mc_autojoin_sk,
                                               false, pfx, dev->ifindex);
                        }
                        return 0;
                }
        }
        read_unlock_bh(&idev->lock);

        NL_SET_ERR_MSG_MOD(extack, "address not found");
        return -EADDRNOTAVAIL;
}


int addrconf_add_ifaddr(struct net *net, void __user *arg)
{
        struct ifa6_config cfg = {
                .ifa_flags = IFA_F_PERMANENT,
                .preferred_lft = INFINITY_LIFE_TIME,
                .valid_lft = INFINITY_LIFE_TIME,
        };
        struct net_device *dev;
        struct in6_ifreq ireq;
        int err;

        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                return -EFAULT;

        cfg.pfx = &ireq.ifr6_addr;
        cfg.plen = ireq.ifr6_prefixlen;

        rtnl_net_lock(net);
        dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
        if (dev) {
                netdev_lock_ops(dev);
                err = inet6_addr_add(net, dev, &cfg, 0, 0, NULL);
                netdev_unlock_ops(dev);
        } else {
                err = -ENODEV;
        }
        rtnl_net_unlock(net);
        return err;
}

int addrconf_del_ifaddr(struct net *net, void __user *arg)
{
        struct in6_ifreq ireq;
        int err;

        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

        if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
                return -EFAULT;

        rtnl_net_lock(net);
        err = inet6_addr_del(net, ireq.ifr6_ifindex, 0, &ireq.ifr6_addr,
                             ireq.ifr6_prefixlen, NULL);
        rtnl_net_unlock(net);
        return err;
}

static void add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
                     int plen, int scope, u8 proto)
{
        struct inet6_ifaddr *ifp;
        struct ifa6_config cfg = {
                .pfx = addr,
                .plen = plen,
                .ifa_flags = IFA_F_PERMANENT,
                .valid_lft = INFINITY_LIFE_TIME,
                .preferred_lft = INFINITY_LIFE_TIME,
                .scope = scope,
                .ifa_proto = proto
        };

        ifp = ipv6_add_addr(idev, &cfg, true, NULL);
        if (!IS_ERR(ifp)) {
                spin_lock_bh(&ifp->lock);
                ifp->flags &= ~IFA_F_TENTATIVE;
                spin_unlock_bh(&ifp->lock);
                rt_genid_bump_ipv6(dev_net(idev->dev));
                ipv6_ifa_notify(RTM_NEWADDR, ifp);
                in6_ifa_put(ifp);
        }
}

#if IS_ENABLED(CONFIG_IPV6_SIT) || IS_ENABLED(CONFIG_NET_IPGRE)
static void add_v4_addrs(struct inet6_dev *idev)
{
        struct in6_addr addr;
        struct net_device *dev;
        struct net *net = dev_net(idev->dev);
        int scope, plen;
        u32 pflags = 0;

        ASSERT_RTNL();

        memset(&addr, 0, sizeof(struct in6_addr));
        memcpy(&addr.s6_addr32[3], idev->dev->dev_addr, 4);

        if (!(idev->dev->flags & IFF_POINTOPOINT) && idev->dev->type == ARPHRD_SIT) {
                scope = IPV6_ADDR_COMPATv4;
                plen = 96;
                pflags |= RTF_NONEXTHOP;
        } else {
                if (idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_NONE)
                        return;

                addr.s6_addr32[0] = htonl(0xfe800000);
                scope = IFA_LINK;
                plen = 64;
        }

        if (addr.s6_addr32[3]) {
                add_addr(idev, &addr, plen, scope, IFAPROT_UNSPEC);
                addrconf_prefix_route(&addr, plen, 0, idev->dev, 0, pflags,
                                      GFP_KERNEL);
                return;
        }

        for_each_netdev(net, dev) {
                struct in_device *in_dev = __in_dev_get_rtnl(dev);
                if (in_dev && (dev->flags & IFF_UP)) {
                        struct in_ifaddr *ifa;
                        int flag = scope;

                        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                                addr.s6_addr32[3] = ifa->ifa_local;

                                if (ifa->ifa_scope == RT_SCOPE_LINK)
                                        continue;
                                if (ifa->ifa_scope >= RT_SCOPE_HOST) {
                                        if (idev->dev->flags&IFF_POINTOPOINT)
                                                continue;
                                        flag |= IFA_HOST;
                                }

                                add_addr(idev, &addr, plen, flag,
                                         IFAPROT_UNSPEC);
                                addrconf_prefix_route(&addr, plen, 0, idev->dev,
                                                      0, pflags, GFP_KERNEL);
                        }
                }
        }
}
#endif

static void init_loopback(struct net_device *dev)
{
        struct inet6_dev  *idev;

        /* ::1 */

        ASSERT_RTNL();

        idev = ipv6_find_idev(dev);
        if (IS_ERR(idev)) {
                pr_debug("%s: add_dev failed\n", __func__);
                return;
        }

        add_addr(idev, &in6addr_loopback, 128, IFA_HOST, IFAPROT_KERNEL_LO);
}

void addrconf_add_linklocal(struct inet6_dev *idev,
                            const struct in6_addr *addr, u32 flags)
{
        struct ifa6_config cfg = {
                .pfx = addr,
                .plen = 64,
                .ifa_flags = flags | IFA_F_PERMANENT,
                .valid_lft = INFINITY_LIFE_TIME,
                .preferred_lft = INFINITY_LIFE_TIME,
                .scope = IFA_LINK,
                .ifa_proto = IFAPROT_KERNEL_LL
        };
        struct inet6_ifaddr *ifp;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        if ((READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad) ||
             READ_ONCE(idev->cnf.optimistic_dad)) &&
            !dev_net(idev->dev)->ipv6.devconf_all->forwarding)
                cfg.ifa_flags |= IFA_F_OPTIMISTIC;
#endif

        ifp = ipv6_add_addr(idev, &cfg, true, NULL);
        if (!IS_ERR(ifp)) {
                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, 0, idev->dev,
                                      0, 0, GFP_ATOMIC);
                addrconf_dad_start(ifp);
                in6_ifa_put(ifp);
        }
}
EXPORT_SYMBOL_GPL(addrconf_add_linklocal);

static bool ipv6_reserved_interfaceid(struct in6_addr address)
{
        if ((address.s6_addr32[2] | address.s6_addr32[3]) == 0)
                return true;

        if (address.s6_addr32[2] == htonl(0x02005eff) &&
            ((address.s6_addr32[3] & htonl(0xfe000000)) == htonl(0xfe000000)))
                return true;

        if (address.s6_addr32[2] == htonl(0xfdffffff) &&
            ((address.s6_addr32[3] & htonl(0xffffff80)) == htonl(0xffffff80)))
                return true;

        return false;
}

static int ipv6_generate_stable_address(struct in6_addr *address,
                                        u8 dad_count,
                                        const struct inet6_dev *idev)
{
        static DEFINE_SPINLOCK(lock);
        static struct sha1_ctx sha_ctx;

        static union {
                u8 __data[SHA1_BLOCK_SIZE];
                struct {
                        struct in6_addr secret;
                        __be32 prefix[2];
                        unsigned char hwaddr[MAX_ADDR_LEN];
                        u8 dad_count;
                } __packed;
        } data;

        struct in6_addr secret;
        struct in6_addr temp;
        struct net *net = dev_net(idev->dev);

        BUILD_BUG_ON(sizeof(data.__data) != sizeof(data));

        if (idev->cnf.stable_secret.initialized)
                secret = idev->cnf.stable_secret.secret;
        else if (net->ipv6.devconf_dflt->stable_secret.initialized)
                secret = net->ipv6.devconf_dflt->stable_secret.secret;
        else
                return -1;

retry:
        spin_lock_bh(&lock);

        sha1_init(&sha_ctx);

        memset(&data, 0, sizeof(data));
        memcpy(data.hwaddr, idev->dev->perm_addr, idev->dev->addr_len);
        data.prefix[0] = address->s6_addr32[0];
        data.prefix[1] = address->s6_addr32[1];
        data.secret = secret;
        data.dad_count = dad_count;

        sha1_update(&sha_ctx, data.__data, sizeof(data));

        /*
         * Note that the SHA-1 finalization is omitted here, and the digest is
         * pulled directly from the internal SHA-1 state (making it incompatible
         * with standard SHA-1).  Unusual, but technically okay since the data
         * length is fixed and is a multiple of the SHA-1 block size.
         */
        temp = *address;
        temp.s6_addr32[2] = (__force __be32)sha_ctx.state.h[0];
        temp.s6_addr32[3] = (__force __be32)sha_ctx.state.h[1];

        spin_unlock_bh(&lock);

        if (ipv6_reserved_interfaceid(temp)) {
                dad_count++;
                if (dad_count > dev_net(idev->dev)->ipv6.sysctl.idgen_retries)
                        return -1;
                goto retry;
        }

        *address = temp;
        return 0;
}

static void ipv6_gen_mode_random_init(struct inet6_dev *idev)
{
        struct ipv6_stable_secret *s = &idev->cnf.stable_secret;

        if (s->initialized)
                return;
        s = &idev->cnf.stable_secret;
        get_random_bytes(&s->secret, sizeof(s->secret));
        s->initialized = true;
}

static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
{
        struct in6_addr addr;

        /* no link local addresses on L3 master devices */
        if (netif_is_l3_master(idev->dev))
                return;

        /* no link local addresses on devices flagged as slaves */
        if (idev->dev->priv_flags & IFF_NO_ADDRCONF)
                return;

        ipv6_addr_set(&addr, htonl(0xFE800000), 0, 0, 0);

        switch (idev->cnf.addr_gen_mode) {
        case IN6_ADDR_GEN_MODE_RANDOM:
                ipv6_gen_mode_random_init(idev);
                fallthrough;
        case IN6_ADDR_GEN_MODE_STABLE_PRIVACY:
                if (!ipv6_generate_stable_address(&addr, 0, idev))
                        addrconf_add_linklocal(idev, &addr,
                                               IFA_F_STABLE_PRIVACY);
                else if (prefix_route)
                        addrconf_prefix_route(&addr, 64, 0, idev->dev,
                                              0, 0, GFP_KERNEL);
                break;
        case IN6_ADDR_GEN_MODE_EUI64:
                /* addrconf_add_linklocal also adds a prefix_route and we
                 * only need to care about prefix routes if ipv6_generate_eui64
                 * couldn't generate one.
                 */
                if (ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) == 0)
                        addrconf_add_linklocal(idev, &addr, 0);
                else if (prefix_route)
                        addrconf_prefix_route(&addr, 64, 0, idev->dev,
                                              0, 0, GFP_KERNEL);
                break;
        case IN6_ADDR_GEN_MODE_NONE:
        default:
                /* will not add any link local address */
                break;
        }
}

static void addrconf_dev_config(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        if ((dev->type != ARPHRD_ETHER) &&
            (dev->type != ARPHRD_FDDI) &&
            (dev->type != ARPHRD_ARCNET) &&
            (dev->type != ARPHRD_INFINIBAND) &&
            (dev->type != ARPHRD_IEEE1394) &&
            (dev->type != ARPHRD_TUNNEL6) &&
            (dev->type != ARPHRD_6LOWPAN) &&
            (dev->type != ARPHRD_IP6GRE) &&
            (dev->type != ARPHRD_TUNNEL) &&
            (dev->type != ARPHRD_NONE) &&
            (dev->type != ARPHRD_RAWIP)) {
                /* Alas, we support only Ethernet autoconfiguration. */
                idev = __in6_dev_get(dev);
                if (!IS_ERR_OR_NULL(idev) && dev->flags & IFF_UP &&
                    dev->flags & IFF_MULTICAST)
                        ipv6_mc_up(idev);
                return;
        }

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev))
                return;

        /* this device type has no EUI support */
        if (dev->type == ARPHRD_NONE &&
            idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64)
                WRITE_ONCE(idev->cnf.addr_gen_mode,
                           IN6_ADDR_GEN_MODE_RANDOM);

        addrconf_addr_gen(idev, false);
}

#if IS_ENABLED(CONFIG_IPV6_SIT)
static void addrconf_sit_config(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        /*
         * Configure the tunnel with one of our IPv4
         * addresses... we should configure all of
         * our v4 addrs in the tunnel
         */

        idev = ipv6_find_idev(dev);
        if (IS_ERR(idev)) {
                pr_debug("%s: add_dev failed\n", __func__);
                return;
        }

        if (dev->priv_flags & IFF_ISATAP) {
                addrconf_addr_gen(idev, false);
                return;
        }

        add_v4_addrs(idev);

        if (dev->flags&IFF_POINTOPOINT)
                addrconf_add_mroute(dev);
}
#endif

#if IS_ENABLED(CONFIG_NET_IPGRE)
static void addrconf_gre_config(struct net_device *dev)
{
        struct inet6_dev *idev;

        ASSERT_RTNL();

        idev = addrconf_add_dev(dev);
        if (IS_ERR(idev))
                return;

        /* Generate the IPv6 link-local address using addrconf_addr_gen(),
         * unless we have an IPv4 GRE device not bound to an IP address and
         * which is in EUI64 mode (as __ipv6_isatap_ifid() would fail in this
         * case). Such devices fall back to add_v4_addrs() instead.
         */
        if (!(*(__be32 *)dev->dev_addr == 0 &&
              idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_EUI64)) {
                addrconf_addr_gen(idev, true);
                return;
        }

        add_v4_addrs(idev);
}
#endif

static void addrconf_init_auto_addrs(struct net_device *dev)
{
        switch (dev->type) {
#if IS_ENABLED(CONFIG_IPV6_SIT)
        case ARPHRD_SIT:
                addrconf_sit_config(dev);
                break;
#endif
#if IS_ENABLED(CONFIG_NET_IPGRE)
        case ARPHRD_IPGRE:
                addrconf_gre_config(dev);
                break;
#endif
        case ARPHRD_LOOPBACK:
                init_loopback(dev);
                break;

        default:
                addrconf_dev_config(dev);
                break;
        }
}

static int fixup_permanent_addr(struct net *net,
                                struct inet6_dev *idev,
                                struct inet6_ifaddr *ifp)
{
        /* !fib6_node means the host route was removed from the
         * FIB, for example, if 'lo' device is taken down. In that
         * case regenerate the host route.
         */
        if (!ifp->rt || !ifp->rt->fib6_node) {
                struct fib6_info *f6i, *prev;

                f6i = addrconf_f6i_alloc(net, idev, &ifp->addr, false,
                                         GFP_ATOMIC, NULL);
                if (IS_ERR(f6i))
                        return PTR_ERR(f6i);

                /* ifp->rt can be accessed outside of rtnl */
                spin_lock(&ifp->lock);
                prev = ifp->rt;
                ifp->rt = f6i;
                spin_unlock(&ifp->lock);

                fib6_info_release(prev);
        }

        if (!(ifp->flags & IFA_F_NOPREFIXROUTE)) {
                addrconf_prefix_route(&ifp->addr, ifp->prefix_len,
                                      ifp->rt_priority, idev->dev, 0, 0,
                                      GFP_ATOMIC);
        }

        if (ifp->state == INET6_IFADDR_STATE_PREDAD)
                addrconf_dad_start(ifp);

        return 0;
}

static void addrconf_permanent_addr(struct net *net, struct net_device *dev)
{
        struct inet6_ifaddr *ifp, *tmp;
        struct inet6_dev *idev;

        idev = __in6_dev_get(dev);
        if (!idev)
                return;

        write_lock_bh(&idev->lock);

        list_for_each_entry_safe(ifp, tmp, &idev->addr_list, if_list) {
                if ((ifp->flags & IFA_F_PERMANENT) &&
                    fixup_permanent_addr(net, idev, ifp) < 0) {
                        write_unlock_bh(&idev->lock);

                        net_info_ratelimited("%s: Failed to add prefix route for address %pI6c; dropping\n",
                                             idev->dev->name, &ifp->addr);
                        in6_ifa_hold(ifp);
                        ipv6_del_addr(ifp);
                        write_lock_bh(&idev->lock);
                }
        }

        write_unlock_bh(&idev->lock);
}

static int addrconf_notify(struct notifier_block *this, unsigned long event,
                           void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct netdev_notifier_change_info *change_info;
        struct netdev_notifier_changeupper_info *info;
        struct inet6_dev *idev = __in6_dev_get(dev);
        struct net *net = dev_net(dev);
        int run_pending = 0;
        int err;

        switch (event) {
        case NETDEV_REGISTER:
                if (!idev && dev->mtu >= IPV6_MIN_MTU) {
                        idev = ipv6_add_dev(dev);
                        if (IS_ERR(idev))
                                return notifier_from_errno(PTR_ERR(idev));
                }
                break;

        case NETDEV_CHANGEMTU:
                /* if MTU under IPV6_MIN_MTU stop IPv6 on this interface. */
                if (dev->mtu < IPV6_MIN_MTU) {
                        addrconf_ifdown(dev, dev != net->loopback_dev);
                        break;
                }

                if (idev) {
                        rt6_mtu_change(dev, dev->mtu);
                        WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
                        break;
                }

                /* allocate new idev */
                idev = ipv6_add_dev(dev);
                if (IS_ERR(idev))
                        break;

                /* device is still not ready */
                if (!(idev->if_flags & IF_READY))
                        break;

                run_pending = 1;
                fallthrough;
        case NETDEV_UP:
        case NETDEV_CHANGE:
                if (idev && idev->cnf.disable_ipv6)
                        break;

                if (dev->priv_flags & IFF_NO_ADDRCONF) {
                        if (event == NETDEV_UP && !IS_ERR_OR_NULL(idev) &&
                            dev->flags & IFF_UP && dev->flags & IFF_MULTICAST)
                                ipv6_mc_up(idev);
                        break;
                }

                if (event == NETDEV_UP) {
                        /* restore routes for permanent addresses */
                        addrconf_permanent_addr(net, dev);

                        if (!addrconf_link_ready(dev)) {
                                /* device is not ready yet. */
                                pr_debug("ADDRCONF(NETDEV_UP): %s: link is not ready\n",
                                         dev->name);
                                break;
                        }

                        if (!idev && dev->mtu >= IPV6_MIN_MTU)
                                idev = ipv6_add_dev(dev);

                        if (!IS_ERR_OR_NULL(idev)) {
                                idev->if_flags |= IF_READY;
                                run_pending = 1;
                        }
                } else if (event == NETDEV_CHANGE) {
                        if (!addrconf_link_ready(dev)) {
                                /* device is still not ready. */
                                rt6_sync_down_dev(dev, event);
                                break;
                        }

                        if (!IS_ERR_OR_NULL(idev)) {
                                if (idev->if_flags & IF_READY) {
                                        /* device is already configured -
                                         * but resend MLD reports, we might
                                         * have roamed and need to update
                                         * multicast snooping switches
                                         */
                                        ipv6_mc_up(idev);
                                        change_info = ptr;
                                        if (change_info->flags_changed & IFF_NOARP)
                                                addrconf_dad_run(idev, true);
                                        rt6_sync_up(dev, RTNH_F_LINKDOWN);
                                        break;
                                }
                                idev->if_flags |= IF_READY;
                        }

                        pr_debug("ADDRCONF(NETDEV_CHANGE): %s: link becomes ready\n",
                                 dev->name);

                        run_pending = 1;
                }

                addrconf_init_auto_addrs(dev);

                if (!IS_ERR_OR_NULL(idev)) {
                        if (run_pending)
                                addrconf_dad_run(idev, false);

                        /* Device has an address by now */
                        rt6_sync_up(dev, RTNH_F_DEAD);

                        /*
                         * If the MTU changed during the interface down,
                         * when the interface up, the changed MTU must be
                         * reflected in the idev as well as routers.
                         */
                        if (idev->cnf.mtu6 != dev->mtu &&
                            dev->mtu >= IPV6_MIN_MTU) {
                                rt6_mtu_change(dev, dev->mtu);
                                WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
                        }
                        WRITE_ONCE(idev->tstamp, jiffies);
                        inet6_ifinfo_notify(RTM_NEWLINK, idev);

                        /*
                         * If the changed mtu during down is lower than
                         * IPV6_MIN_MTU stop IPv6 on this interface.
                         */
                        if (dev->mtu < IPV6_MIN_MTU)
                                addrconf_ifdown(dev, dev != net->loopback_dev);
                }
                break;

        case NETDEV_DOWN:
        case NETDEV_UNREGISTER:
                /*
                 *      Remove all addresses from this interface.
                 */
                addrconf_ifdown(dev, event != NETDEV_DOWN);
                break;

        case NETDEV_CHANGENAME:
                if (idev) {
                        snmp6_unregister_dev(idev);
                        addrconf_sysctl_unregister(idev);
                        err = addrconf_sysctl_register(idev);
                        if (err)
                                return notifier_from_errno(err);
                        err = snmp6_register_dev(idev);
                        if (err) {
                                addrconf_sysctl_unregister(idev);
                                return notifier_from_errno(err);
                        }
                }
                break;

        case NETDEV_PRE_TYPE_CHANGE:
        case NETDEV_POST_TYPE_CHANGE:
                if (idev)
                        addrconf_type_change(dev, event);
                break;

        case NETDEV_CHANGEUPPER:
                info = ptr;

                /* flush all routes if dev is linked to or unlinked from
                 * an L3 master device (e.g., VRF)
                 */
                if (info->upper_dev && netif_is_l3_master(info->upper_dev))
                        addrconf_ifdown(dev, false);
        }

        return NOTIFY_OK;
}

/*
 *      addrconf module should be notified of a device going up
 */
static struct notifier_block ipv6_dev_notf = {
        .notifier_call = addrconf_notify,
        .priority = ADDRCONF_NOTIFY_PRIORITY,
};

static void addrconf_type_change(struct net_device *dev, unsigned long event)
{
        struct inet6_dev *idev;
        ASSERT_RTNL();

        idev = __in6_dev_get(dev);

        if (event == NETDEV_POST_TYPE_CHANGE)
                ipv6_mc_remap(idev);
        else if (event == NETDEV_PRE_TYPE_CHANGE)
                ipv6_mc_unmap(idev);
}

static bool addr_is_local(const struct in6_addr *addr)
{
        return ipv6_addr_type(addr) &
                (IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
}

static int addrconf_ifdown(struct net_device *dev, bool unregister)
{
        unsigned long event = unregister ? NETDEV_UNREGISTER : NETDEV_DOWN;
        struct net *net = dev_net(dev);
        struct inet6_dev *idev;
        struct inet6_ifaddr *ifa;
        LIST_HEAD(tmp_addr_list);
        bool keep_addr = false;
        bool was_ready;
        int state, i;

        ASSERT_RTNL();

        rt6_disable_ip(dev, event);

        idev = __in6_dev_get(dev);
        if (!idev)
                return -ENODEV;

        /*
         * Step 1: remove reference to ipv6 device from parent device.
         *         Do not dev_put!
         */
        if (unregister) {
                WRITE_ONCE(idev->dead, 1);

                /* protected by rtnl_lock */
                RCU_INIT_POINTER(dev->ip6_ptr, NULL);

                /* Step 1.5: remove snmp6 entry */
                snmp6_unregister_dev(idev);

        }

        /* combine the user config with event to determine if permanent
         * addresses are to be removed from address hash table
         */
        if (!unregister && !idev->cnf.disable_ipv6) {
                /* aggregate the system setting and interface setting */
                int _keep_addr = READ_ONCE(net->ipv6.devconf_all->keep_addr_on_down);

                if (!_keep_addr)
                        _keep_addr = READ_ONCE(idev->cnf.keep_addr_on_down);

                keep_addr = (_keep_addr > 0);
        }

        /* Step 2: clear hash table */
        for (i = 0; i < IN6_ADDR_HSIZE; i++) {
                struct hlist_head *h = &net->ipv6.inet6_addr_lst[i];

                spin_lock_bh(&net->ipv6.addrconf_hash_lock);
restart:
                hlist_for_each_entry_rcu(ifa, h, addr_lst) {
                        if (ifa->idev == idev) {
                                addrconf_del_dad_work(ifa);
                                /* combined flag + permanent flag decide if
                                 * address is retained on a down event
                                 */
                                if (!keep_addr ||
                                    !(ifa->flags & IFA_F_PERMANENT) ||
                                    addr_is_local(&ifa->addr)) {
                                        hlist_del_init_rcu(&ifa->addr_lst);
                                        goto restart;
                                }
                        }
                }
                spin_unlock_bh(&net->ipv6.addrconf_hash_lock);
        }

        write_lock_bh(&idev->lock);

        addrconf_del_rs_timer(idev);

        /* Step 2: clear flags for stateless addrconf, repeated down
         *         detection
         */
        was_ready = idev->if_flags & IF_READY;
        if (!unregister)
                idev->if_flags &= ~(IF_RS_SENT|IF_RA_RCVD|IF_READY);

        /* Step 3: clear tempaddr list */
        while (!list_empty(&idev->tempaddr_list)) {
                ifa = list_first_entry(&idev->tempaddr_list,
                                       struct inet6_ifaddr, tmp_list);
                list_del(&ifa->tmp_list);
                write_unlock_bh(&idev->lock);
                spin_lock_bh(&ifa->lock);

                if (ifa->ifpub) {
                        in6_ifa_put(ifa->ifpub);
                        ifa->ifpub = NULL;
                }
                spin_unlock_bh(&ifa->lock);
                in6_ifa_put(ifa);
                write_lock_bh(&idev->lock);
        }

        list_for_each_entry(ifa, &idev->addr_list, if_list)
                list_add_tail(&ifa->if_list_aux, &tmp_addr_list);
        write_unlock_bh(&idev->lock);

        while (!list_empty(&tmp_addr_list)) {
                struct fib6_info *rt = NULL;
                bool keep;

                ifa = list_first_entry(&tmp_addr_list,
                                       struct inet6_ifaddr, if_list_aux);
                list_del(&ifa->if_list_aux);

                addrconf_del_dad_work(ifa);

                keep = keep_addr && (ifa->flags & IFA_F_PERMANENT) &&
                        !addr_is_local(&ifa->addr);

                spin_lock_bh(&ifa->lock);

                if (keep) {
                        /* set state to skip the notifier below */
                        state = INET6_IFADDR_STATE_DEAD;
                        ifa->state = INET6_IFADDR_STATE_PREDAD;
                        if (!(ifa->flags & IFA_F_NODAD))
                                ifa->flags |= IFA_F_TENTATIVE;

                        rt = ifa->rt;
                        ifa->rt = NULL;
                } else {
                        state = ifa->state;
                        ifa->state = INET6_IFADDR_STATE_DEAD;
                }

                spin_unlock_bh(&ifa->lock);

                if (rt)
                        ip6_del_rt(net, rt, false);

                if (state != INET6_IFADDR_STATE_DEAD) {
                        __ipv6_ifa_notify(RTM_DELADDR, ifa);
                        inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
                } else {
                        if (idev->cnf.forwarding)
                                addrconf_leave_anycast(ifa);
                        addrconf_leave_solict(ifa->idev, &ifa->addr);
                }

                if (!keep) {
                        write_lock_bh(&idev->lock);
                        list_del_rcu(&ifa->if_list);
                        write_unlock_bh(&idev->lock);
                        in6_ifa_put(ifa);
                }
        }

        /* Step 5: Discard anycast and multicast list */
        if (unregister) {
                ipv6_ac_destroy_dev(idev);
                ipv6_mc_destroy_dev(idev);
        } else if (was_ready) {
                ipv6_mc_down(idev);
        }

        WRITE_ONCE(idev->tstamp, jiffies);
        idev->ra_mtu = 0;

        /* Last: Shot the device (if unregistered) */
        if (unregister) {
                addrconf_sysctl_unregister(idev);
                neigh_parms_release(&nd_tbl, idev->nd_parms);
                neigh_ifdown(&nd_tbl, dev);
                in6_dev_put(idev);
        }
        return 0;
}

static void addrconf_rs_timer(struct timer_list *t)
{
        struct inet6_dev *idev = timer_container_of(idev, t, rs_timer);
        struct net_device *dev = idev->dev;
        struct in6_addr lladdr;
        int rtr_solicits;

        write_lock(&idev->lock);
        if (idev->dead || !(idev->if_flags & IF_READY))
                goto out;

        if (!ipv6_accept_ra(idev))
                goto out;

        /* Announcement received after solicitation was sent */
        if (idev->if_flags & IF_RA_RCVD)
                goto out;

        rtr_solicits = READ_ONCE(idev->cnf.rtr_solicits);

        if (idev->rs_probes++ < rtr_solicits || rtr_solicits < 0) {
                write_unlock(&idev->lock);
                if (!ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
                        ndisc_send_rs(dev, &lladdr,
                                      &in6addr_linklocal_allrouters);
                else
                        goto put;

                write_lock(&idev->lock);
                idev->rs_interval = rfc3315_s14_backoff_update(
                                idev->rs_interval,
                                READ_ONCE(idev->cnf.rtr_solicit_max_interval));
                /* The wait after the last probe can be shorter */
                addrconf_mod_rs_timer(idev, (idev->rs_probes ==
                                             READ_ONCE(idev->cnf.rtr_solicits)) ?
                                      READ_ONCE(idev->cnf.rtr_solicit_delay) :
                                      idev->rs_interval);
        } else {
                /*
                 * Note: we do not support deprecated "all on-link"
                 * assumption any longer.
                 */
                pr_debug("%s: no IPv6 routers present\n", idev->dev->name);
        }

out:
        write_unlock(&idev->lock);
put:
        in6_dev_put(idev);
}

/*
 *      Duplicate Address Detection
 */
static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
{
        struct inet6_dev *idev = ifp->idev;
        unsigned long rand_num;
        u64 nonce;

        if (ifp->flags & IFA_F_OPTIMISTIC)
                rand_num = 0;
        else
                rand_num = get_random_u32_below(
                                READ_ONCE(idev->cnf.rtr_solicit_delay) ? : 1);

        nonce = 0;
        if (READ_ONCE(idev->cnf.enhanced_dad) ||
            READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->enhanced_dad)) {
                do
                        get_random_bytes(&nonce, 6);
                while (nonce == 0);
        }
        ifp->dad_nonce = nonce;
        ifp->dad_probes = READ_ONCE(idev->cnf.dad_transmits);
        addrconf_mod_dad_work(ifp, rand_num);
}

static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
{
        struct inet6_dev *idev = ifp->idev;
        struct net_device *dev = idev->dev;
        bool bump_id, notify = false;
        struct net *net;

        addrconf_join_solict(dev, &ifp->addr);

        read_lock_bh(&idev->lock);
        spin_lock(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_DEAD)
                goto out;

        net = dev_net(dev);
        if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
            (READ_ONCE(net->ipv6.devconf_all->accept_dad) < 1 &&
             READ_ONCE(idev->cnf.accept_dad) < 1) ||
            !(ifp->flags&IFA_F_TENTATIVE) ||
            ifp->flags & IFA_F_NODAD) {
                bool send_na = false;

                if (ifp->flags & IFA_F_TENTATIVE &&
                    !(ifp->flags & IFA_F_OPTIMISTIC))
                        send_na = true;
                bump_id = ifp->flags & IFA_F_TENTATIVE;
                ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
                spin_unlock(&ifp->lock);
                read_unlock_bh(&idev->lock);

                addrconf_dad_completed(ifp, bump_id, send_na);
                return;
        }

        if (!(idev->if_flags & IF_READY)) {
                spin_unlock(&ifp->lock);
                read_unlock_bh(&idev->lock);
                /*
                 * If the device is not ready:
                 * - keep it tentative if it is a permanent address.
                 * - otherwise, kill it.
                 */
                in6_ifa_hold(ifp);
                addrconf_dad_stop(ifp, 0);
                return;
        }

        /*
         * Optimistic nodes can start receiving
         * Frames right away
         */
        if (ifp->flags & IFA_F_OPTIMISTIC) {
                ip6_ins_rt(net, ifp->rt);
                if (ipv6_use_optimistic_addr(net, idev)) {
                        /* Because optimistic nodes can use this address,
                         * notify listeners. If DAD fails, RTM_DELADDR is sent.
                         */
                        notify = true;
                }
        }

        addrconf_dad_kick(ifp);
out:
        spin_unlock(&ifp->lock);
        read_unlock_bh(&idev->lock);
        if (notify)
                ipv6_ifa_notify(RTM_NEWADDR, ifp);
}

static void addrconf_dad_start(struct inet6_ifaddr *ifp)
{
        bool begin_dad = false;

        spin_lock_bh(&ifp->lock);
        if (ifp->state != INET6_IFADDR_STATE_DEAD) {
                ifp->state = INET6_IFADDR_STATE_PREDAD;
                begin_dad = true;
        }
        spin_unlock_bh(&ifp->lock);

        if (begin_dad)
                addrconf_mod_dad_work(ifp, 0);
}

static void addrconf_dad_work(struct work_struct *w)
{
        struct inet6_ifaddr *ifp = container_of(to_delayed_work(w),
                                                struct inet6_ifaddr,
                                                dad_work);
        struct inet6_dev *idev = ifp->idev;
        bool bump_id, disable_ipv6 = false;
        struct in6_addr mcaddr;
        struct net *net;

        enum {
                DAD_PROCESS,
                DAD_BEGIN,
                DAD_ABORT,
        } action = DAD_PROCESS;

        net = dev_net(idev->dev);

        rtnl_net_lock(net);

        spin_lock_bh(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_PREDAD) {
                action = DAD_BEGIN;
                ifp->state = INET6_IFADDR_STATE_DAD;
        } else if (ifp->state == INET6_IFADDR_STATE_ERRDAD) {
                action = DAD_ABORT;
                ifp->state = INET6_IFADDR_STATE_POSTDAD;

                if ((READ_ONCE(net->ipv6.devconf_all->accept_dad) > 1 ||
                     READ_ONCE(idev->cnf.accept_dad) > 1) &&
                    !idev->cnf.disable_ipv6 &&
                    !(ifp->flags & IFA_F_STABLE_PRIVACY)) {
                        struct in6_addr addr;

                        addr.s6_addr32[0] = htonl(0xfe800000);
                        addr.s6_addr32[1] = 0;

                        if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
                            ipv6_addr_equal(&ifp->addr, &addr)) {
                                /* DAD failed for link-local based on MAC */
                                WRITE_ONCE(idev->cnf.disable_ipv6, 1);

                                pr_info("%s: IPv6 being disabled!\n",
                                        ifp->idev->dev->name);
                                disable_ipv6 = true;
                        }
                }
        }
        spin_unlock_bh(&ifp->lock);

        if (action == DAD_BEGIN) {
                addrconf_dad_begin(ifp);
                goto out;
        } else if (action == DAD_ABORT) {
                in6_ifa_hold(ifp);
                addrconf_dad_stop(ifp, 1);
                if (disable_ipv6)
                        addrconf_ifdown(idev->dev, false);
                goto out;
        }

        if (!ifp->dad_probes && addrconf_dad_end(ifp))
                goto out;

        write_lock_bh(&idev->lock);
        if (idev->dead || !(idev->if_flags & IF_READY)) {
                write_unlock_bh(&idev->lock);
                goto out;
        }

        spin_lock(&ifp->lock);
        if (ifp->state == INET6_IFADDR_STATE_DEAD) {
                spin_unlock(&ifp->lock);
                write_unlock_bh(&idev->lock);
                goto out;
        }

        if (ifp->dad_probes == 0) {
                bool send_na = false;

                /*
                 * DAD was successful
                 */

                if (ifp->flags & IFA_F_TENTATIVE &&
                    !(ifp->flags & IFA_F_OPTIMISTIC))
                        send_na = true;
                bump_id = ifp->flags & IFA_F_TENTATIVE;
                ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
                spin_unlock(&ifp->lock);
                write_unlock_bh(&idev->lock);

                addrconf_dad_completed(ifp, bump_id, send_na);

                goto out;
        }

        ifp->dad_probes--;
        addrconf_mod_dad_work(ifp,
                              max(NEIGH_VAR(ifp->idev->nd_parms, RETRANS_TIME),
                                  HZ/100));
        spin_unlock(&ifp->lock);
        write_unlock_bh(&idev->lock);

        /* send a neighbour solicitation for our addr */
        addrconf_addr_solict_mult(&ifp->addr, &mcaddr);
        ndisc_send_ns(ifp->idev->dev, &ifp->addr, &mcaddr, &in6addr_any,
                      ifp->dad_nonce);
out:
        in6_ifa_put(ifp);
        rtnl_net_unlock(net);
}

/* ifp->idev must be at least read locked */
static bool ipv6_lonely_lladdr(struct inet6_ifaddr *ifp)
{
        struct inet6_ifaddr *ifpiter;
        struct inet6_dev *idev = ifp->idev;

        list_for_each_entry_reverse(ifpiter, &idev->addr_list, if_list) {
                if (ifpiter->scope > IFA_LINK)
                        break;
                if (ifp != ifpiter && ifpiter->scope == IFA_LINK &&
                    (ifpiter->flags & (IFA_F_PERMANENT|IFA_F_TENTATIVE|
                                       IFA_F_OPTIMISTIC|IFA_F_DADFAILED)) ==
                    IFA_F_PERMANENT)
                        return false;
        }
        return true;
}

static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
                                   bool send_na)
{
        struct net_device *dev = ifp->idev->dev;
        struct in6_addr lladdr;
        bool send_rs, send_mld;

        addrconf_del_dad_work(ifp);

        /*
         *      Configure the address for reception. Now it is valid.
         */

        ipv6_ifa_notify(RTM_NEWADDR, ifp);

        /* If added prefix is link local and we are prepared to process
           router advertisements, start sending router solicitations.
         */

        read_lock_bh(&ifp->idev->lock);
        send_mld = ifp->scope == IFA_LINK && ipv6_lonely_lladdr(ifp);
        send_rs = send_mld &&
                  ipv6_accept_ra(ifp->idev) &&
                  READ_ONCE(ifp->idev->cnf.rtr_solicits) != 0 &&
                  (dev->flags & IFF_LOOPBACK) == 0 &&
                  (dev->type != ARPHRD_TUNNEL) &&
                  !netif_is_team_port(dev);
        read_unlock_bh(&ifp->idev->lock);

        /* While dad is in progress mld report's source address is in6_addrany.
         * Resend with proper ll now.
         */
        if (send_mld)
                ipv6_mc_dad_complete(ifp->idev);

        /* send unsolicited NA if enabled */
        if (send_na &&
            (READ_ONCE(ifp->idev->cnf.ndisc_notify) ||
             READ_ONCE(dev_net(dev)->ipv6.devconf_all->ndisc_notify))) {
                ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifp->addr,
                              /*router=*/ !!ifp->idev->cnf.forwarding,
                              /*solicited=*/ false, /*override=*/ true,
                              /*inc_opt=*/ true);
        }

        if (send_rs) {
                /*
                 *      If a host as already performed a random delay
                 *      [...] as part of DAD [...] there is no need
                 *      to delay again before sending the first RS
                 */
                if (ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
                        return;
                ndisc_send_rs(dev, &lladdr, &in6addr_linklocal_allrouters);

                write_lock_bh(&ifp->idev->lock);
                spin_lock(&ifp->lock);
                ifp->idev->rs_interval = rfc3315_s14_backoff_init(
                        READ_ONCE(ifp->idev->cnf.rtr_solicit_interval));
                ifp->idev->rs_probes = 1;
                ifp->idev->if_flags |= IF_RS_SENT;
                addrconf_mod_rs_timer(ifp->idev, ifp->idev->rs_interval);
                spin_unlock(&ifp->lock);
                write_unlock_bh(&ifp->idev->lock);
        }

        if (bump_id)
                rt_genid_bump_ipv6(dev_net(dev));

        /* Make sure that a new temporary address will be created
         * before this temporary address becomes deprecated.
         */
        if (ifp->flags & IFA_F_TEMPORARY)
                addrconf_verify_rtnl(dev_net(dev));
}

static void addrconf_dad_run(struct inet6_dev *idev, bool restart)
{
        struct inet6_ifaddr *ifp;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                spin_lock(&ifp->lock);
                if ((ifp->flags & IFA_F_TENTATIVE &&
                     ifp->state == INET6_IFADDR_STATE_DAD) || restart) {
                        if (restart)
                                ifp->state = INET6_IFADDR_STATE_PREDAD;
                        addrconf_dad_kick(ifp);
                }
                spin_unlock(&ifp->lock);
        }
        read_unlock_bh(&idev->lock);
}

#ifdef CONFIG_PROC_FS
struct if6_iter_state {
        struct seq_net_private p;
        int bucket;
        int offset;
};

static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)
{
        struct if6_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);
        struct inet6_ifaddr *ifa = NULL;
        int p = 0;

        /* initial bucket if pos is 0 */
        if (pos == 0) {
                state->bucket = 0;
                state->offset = 0;
        }

        for (; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {
                hlist_for_each_entry_rcu(ifa, &net->ipv6.inet6_addr_lst[state->bucket],
                                         addr_lst) {
                        /* sync with offset */
                        if (p < state->offset) {
                                p++;
                                continue;
                        }
                        return ifa;
                }

                /* prepare for next bucket */
                state->offset = 0;
                p = 0;
        }
        return NULL;
}

static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
                                         struct inet6_ifaddr *ifa)
{
        struct if6_iter_state *state = seq->private;
        struct net *net = seq_file_net(seq);

        hlist_for_each_entry_continue_rcu(ifa, addr_lst) {
                state->offset++;
                return ifa;
        }

        state->offset = 0;
        while (++state->bucket < IN6_ADDR_HSIZE) {
                hlist_for_each_entry_rcu(ifa,
                                     &net->ipv6.inet6_addr_lst[state->bucket], addr_lst) {
                        return ifa;
                }
        }

        return NULL;
}

static void *if6_seq_start(struct seq_file *seq, loff_t *pos)
        __acquires(rcu)
{
        rcu_read_lock();
        return if6_get_first(seq, *pos);
}

static void *if6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct inet6_ifaddr *ifa;

        ifa = if6_get_next(seq, v);
        ++*pos;
        return ifa;
}

static void if6_seq_stop(struct seq_file *seq, void *v)
        __releases(rcu)
{
        rcu_read_unlock();
}

static int if6_seq_show(struct seq_file *seq, void *v)
{
        struct inet6_ifaddr *ifp = (struct inet6_ifaddr *)v;
        seq_printf(seq, "%pi6 %02x %02x %02x %02x %8s\n",
                   &ifp->addr,
                   ifp->idev->dev->ifindex,
                   ifp->prefix_len,
                   ifp->scope,
                   (u8) ifp->flags,
                   ifp->idev->dev->name);
        return 0;
}

static const struct seq_operations if6_seq_ops = {
        .start  = if6_seq_start,
        .next   = if6_seq_next,
        .show   = if6_seq_show,
        .stop   = if6_seq_stop,
};

static int __net_init if6_proc_net_init(struct net *net)
{
        if (!proc_create_net("if_inet6", 0444, net->proc_net, &if6_seq_ops,
                        sizeof(struct if6_iter_state)))
                return -ENOMEM;
        return 0;
}

static void __net_exit if6_proc_net_exit(struct net *net)
{
        remove_proc_entry("if_inet6", net->proc_net);
}

static struct pernet_operations if6_proc_net_ops = {
        .init = if6_proc_net_init,
        .exit = if6_proc_net_exit,
};

int __init if6_proc_init(void)
{
        return register_pernet_subsys(&if6_proc_net_ops);
}

void if6_proc_exit(void)
{
        unregister_pernet_subsys(&if6_proc_net_ops);
}
#endif  /* CONFIG_PROC_FS */

#if IS_ENABLED(CONFIG_IPV6_MIP6)
/* Check if address is a home address configured on any interface. */
int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
{
        unsigned int hash = inet6_addr_hash(net, addr);
        struct inet6_ifaddr *ifp = NULL;
        int ret = 0;

        rcu_read_lock();
        hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
                if (ipv6_addr_equal(&ifp->addr, addr) &&
                    (ifp->flags & IFA_F_HOMEADDRESS)) {
                        ret = 1;
                        break;
                }
        }
        rcu_read_unlock();
        return ret;
}
#endif

/* RFC6554 has some algorithm to avoid loops in segment routing by
 * checking if the segments contains any of a local interface address.
 *
 * Quote:
 *
 * To detect loops in the SRH, a router MUST determine if the SRH
 * includes multiple addresses assigned to any interface on that router.
 * If such addresses appear more than once and are separated by at least
 * one address not assigned to that router.
 */
int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
                          unsigned char nsegs)
{
        const struct in6_addr *addr;
        int i, ret = 0, found = 0;
        struct inet6_ifaddr *ifp;
        bool separated = false;
        unsigned int hash;
        bool hash_found;

        rcu_read_lock();
        for (i = 0; i < nsegs; i++) {
                addr = &segs[i];
                hash = inet6_addr_hash(net, addr);

                hash_found = false;
                hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {

                        if (ipv6_addr_equal(&ifp->addr, addr)) {
                                hash_found = true;
                                break;
                        }
                }

                if (hash_found) {
                        if (found > 1 && separated) {
                                ret = 1;
                                break;
                        }

                        separated = false;
                        found++;
                } else {
                        separated = true;
                }
        }
        rcu_read_unlock();

        return ret;
}

/*
 *      Periodic address status verification
 */

static void addrconf_verify_rtnl(struct net *net)
{
        unsigned long now, next, next_sec, next_sched;
        struct inet6_ifaddr *ifp;
        int i;

        ASSERT_RTNL();

        rcu_read_lock_bh();
        now = jiffies;
        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);

        cancel_delayed_work(&net->ipv6.addr_chk_work);

        for (i = 0; i < IN6_ADDR_HSIZE; i++) {
restart:
                hlist_for_each_entry_rcu_bh(ifp, &net->ipv6.inet6_addr_lst[i], addr_lst) {
                        unsigned long age;

                        /* When setting preferred_lft to a value not zero or
                         * infinity, while valid_lft is infinity
                         * IFA_F_PERMANENT has a non-infinity life time.
                         */
                        if ((ifp->flags & IFA_F_PERMANENT) &&
                            (ifp->prefered_lft == INFINITY_LIFE_TIME))
                                continue;

                        spin_lock(&ifp->lock);
                        /* We try to batch several events at once. */
                        age = (now - ifp->tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ;

                        if ((ifp->flags&IFA_F_TEMPORARY) &&
                            !(ifp->flags&IFA_F_TENTATIVE) &&
                            ifp->prefered_lft != INFINITY_LIFE_TIME &&
                            !ifp->regen_count && ifp->ifpub) {
                                /* This is a non-regenerated temporary addr. */

                                unsigned long regen_advance = ipv6_get_regen_advance(ifp->idev);

                                if (age + regen_advance >= ifp->prefered_lft) {
                                        struct inet6_ifaddr *ifpub = ifp->ifpub;
                                        if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
                                                next = ifp->tstamp + ifp->prefered_lft * HZ;

                                        ifp->regen_count++;
                                        in6_ifa_hold(ifp);
                                        in6_ifa_hold(ifpub);
                                        spin_unlock(&ifp->lock);

                                        spin_lock(&ifpub->lock);
                                        ifpub->regen_count = 0;
                                        spin_unlock(&ifpub->lock);
                                        rcu_read_unlock_bh();
                                        ipv6_create_tempaddr(ifpub, true);
                                        in6_ifa_put(ifpub);
                                        in6_ifa_put(ifp);
                                        rcu_read_lock_bh();
                                        goto restart;
                                } else if (time_before(ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ, next))
                                        next = ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ;
                        }

                        if (ifp->valid_lft != INFINITY_LIFE_TIME &&
                            age >= ifp->valid_lft) {
                                spin_unlock(&ifp->lock);
                                in6_ifa_hold(ifp);
                                rcu_read_unlock_bh();
                                ipv6_del_addr(ifp);
                                rcu_read_lock_bh();
                                goto restart;
                        } else if (ifp->prefered_lft == INFINITY_LIFE_TIME) {
                                spin_unlock(&ifp->lock);
                                continue;
                        } else if (age >= ifp->prefered_lft) {
                                /* jiffies - ifp->tstamp > age >= ifp->prefered_lft */
                                int deprecate = 0;

                                if (!(ifp->flags&IFA_F_DEPRECATED)) {
                                        deprecate = 1;
                                        ifp->flags |= IFA_F_DEPRECATED;
                                }

                                if ((ifp->valid_lft != INFINITY_LIFE_TIME) &&
                                    (time_before(ifp->tstamp + ifp->valid_lft * HZ, next)))
                                        next = ifp->tstamp + ifp->valid_lft * HZ;

                                spin_unlock(&ifp->lock);

                                if (deprecate) {
                                        in6_ifa_hold(ifp);

                                        ipv6_ifa_notify(0, ifp);
                                        in6_ifa_put(ifp);
                                        goto restart;
                                }
                        } else {
                                /* ifp->prefered_lft <= ifp->valid_lft */
                                if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next))
                                        next = ifp->tstamp + ifp->prefered_lft * HZ;
                                spin_unlock(&ifp->lock);
                        }
                }
        }

        next_sec = round_jiffies_up(next);
        next_sched = next;

        /* If rounded timeout is accurate enough, accept it. */
        if (time_before(next_sec, next + ADDRCONF_TIMER_FUZZ))
                next_sched = next_sec;

        /* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
        if (time_before(next_sched, jiffies + ADDRCONF_TIMER_FUZZ_MAX))
                next_sched = jiffies + ADDRCONF_TIMER_FUZZ_MAX;

        pr_debug("now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",
                 now, next, next_sec, next_sched);
        mod_delayed_work(addrconf_wq, &net->ipv6.addr_chk_work, next_sched - now);
        rcu_read_unlock_bh();
}

static void addrconf_verify_work(struct work_struct *w)
{
        struct net *net = container_of(to_delayed_work(w), struct net,
                                       ipv6.addr_chk_work);

        rtnl_net_lock(net);
        addrconf_verify_rtnl(net);
        rtnl_net_unlock(net);
}

static void addrconf_verify(struct net *net)
{
        mod_delayed_work(addrconf_wq, &net->ipv6.addr_chk_work, 0);
}

static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,
                                     struct in6_addr **peer_pfx)
{
        struct in6_addr *pfx = NULL;

        *peer_pfx = NULL;

        if (addr)
                pfx = nla_data(addr);

        if (local) {
                if (pfx && nla_memcmp(local, pfx, sizeof(*pfx)))
                        *peer_pfx = pfx;
                pfx = nla_data(local);
        }

        return pfx;
}

static const struct nla_policy ifa_ipv6_policy[IFA_MAX+1] = {
        [IFA_ADDRESS]           = { .len = sizeof(struct in6_addr) },
        [IFA_LOCAL]             = { .len = sizeof(struct in6_addr) },
        [IFA_CACHEINFO]         = { .len = sizeof(struct ifa_cacheinfo) },
        [IFA_FLAGS]             = { .len = sizeof(u32) },
        [IFA_RT_PRIORITY]       = { .len = sizeof(u32) },
        [IFA_TARGET_NETNSID]    = { .type = NLA_S32 },
        [IFA_PROTO]             = { .type = NLA_U8 },
};

static int
inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
                  struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
        struct in6_addr *pfx, *peer_pfx;
        u32 ifa_flags;
        int err;

        err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
                                     ifa_ipv6_policy, extack);
        if (err < 0)
                return err;

        ifm = nlmsg_data(nlh);
        pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
        if (!pfx)
                return -EINVAL;

        ifa_flags = nla_get_u32_default(tb[IFA_FLAGS], ifm->ifa_flags);

        /* We ignore other flags so far. */
        ifa_flags &= IFA_F_MANAGETEMPADDR;

        rtnl_net_lock(net);
        err = inet6_addr_del(net, ifm->ifa_index, ifa_flags, pfx,
                             ifm->ifa_prefixlen, extack);
        rtnl_net_unlock(net);

        return err;
}

static int modify_prefix_route(struct net *net, struct inet6_ifaddr *ifp,
                               unsigned long expires, u32 flags,
                               bool modify_peer)
{
        struct fib6_table *table;
        struct fib6_info *f6i;
        u32 prio;

        f6i = addrconf_get_prefix_route(modify_peer ? &ifp->peer_addr : &ifp->addr,
                                        ifp->prefix_len,
                                        ifp->idev->dev, 0, RTF_DEFAULT, true);
        if (!f6i)
                return -ENOENT;

        prio = ifp->rt_priority ? : IP6_RT_PRIO_ADDRCONF;
        if (f6i->fib6_metric != prio) {
                /* delete old one */
                ip6_del_rt(dev_net(ifp->idev->dev), f6i, false);

                /* add new one */
                addrconf_prefix_route(modify_peer ? &ifp->peer_addr : &ifp->addr,
                                      ifp->prefix_len,
                                      ifp->rt_priority, ifp->idev->dev,
                                      expires, flags, GFP_KERNEL);
                return 0;
        }
        if (f6i != net->ipv6.fib6_null_entry) {
                table = f6i->fib6_table;
                spin_lock_bh(&table->tb6_lock);

                if (!(flags & RTF_EXPIRES)) {
                        fib6_clean_expires(f6i);
                        fib6_may_remove_gc_list(net, f6i);
                } else {
                        fib6_set_expires(f6i, expires);
                        fib6_add_gc_list(f6i);
                }

                spin_unlock_bh(&table->tb6_lock);
        }
        fib6_info_release(f6i);

        return 0;
}

static int inet6_addr_modify(struct net *net, struct inet6_ifaddr *ifp,
                             struct ifa6_config *cfg, clock_t expires,
                             u32 flags)
{
        bool was_managetempaddr;
        bool new_peer = false;
        bool had_prefixroute;

        ASSERT_RTNL_NET(net);

        if (cfg->ifa_flags & IFA_F_MANAGETEMPADDR &&
            (ifp->flags & IFA_F_TEMPORARY || ifp->prefix_len != 64))
                return -EINVAL;

        if (!(ifp->flags & IFA_F_TENTATIVE) || ifp->flags & IFA_F_DADFAILED)
                cfg->ifa_flags &= ~IFA_F_OPTIMISTIC;

        if (cfg->peer_pfx &&
            memcmp(&ifp->peer_addr, cfg->peer_pfx, sizeof(struct in6_addr))) {
                if (!ipv6_addr_any(&ifp->peer_addr))
                        cleanup_prefix_route(ifp, expires, true, true);
                new_peer = true;
        }

        spin_lock_bh(&ifp->lock);
        was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR;
        had_prefixroute = ifp->flags & IFA_F_PERMANENT &&
                          !(ifp->flags & IFA_F_NOPREFIXROUTE);
        ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD |
                        IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
                        IFA_F_NOPREFIXROUTE);
        ifp->flags |= cfg->ifa_flags;
        WRITE_ONCE(ifp->tstamp, jiffies);
        WRITE_ONCE(ifp->valid_lft, cfg->valid_lft);
        WRITE_ONCE(ifp->prefered_lft, cfg->preferred_lft);
        WRITE_ONCE(ifp->ifa_proto, cfg->ifa_proto);

        if (cfg->rt_priority && cfg->rt_priority != ifp->rt_priority)
                WRITE_ONCE(ifp->rt_priority, cfg->rt_priority);

        if (new_peer)
                ifp->peer_addr = *cfg->peer_pfx;

        spin_unlock_bh(&ifp->lock);
        if (!(ifp->flags&IFA_F_TENTATIVE))
                ipv6_ifa_notify(0, ifp);

        if (!(cfg->ifa_flags & IFA_F_NOPREFIXROUTE)) {
                int rc = -ENOENT;

                if (had_prefixroute)
                        rc = modify_prefix_route(net, ifp, expires, flags, false);

                /* prefix route could have been deleted; if so restore it */
                if (rc == -ENOENT) {
                        addrconf_prefix_route(&ifp->addr, ifp->prefix_len,
                                              ifp->rt_priority, ifp->idev->dev,
                                              expires, flags, GFP_KERNEL);
                }

                if (had_prefixroute && !ipv6_addr_any(&ifp->peer_addr))
                        rc = modify_prefix_route(net, ifp, expires, flags, true);

                if (rc == -ENOENT && !ipv6_addr_any(&ifp->peer_addr)) {
                        addrconf_prefix_route(&ifp->peer_addr, ifp->prefix_len,
                                              ifp->rt_priority, ifp->idev->dev,
                                              expires, flags, GFP_KERNEL);
                }
        } else if (had_prefixroute) {
                enum cleanup_prefix_rt_t action;
                unsigned long rt_expires;

                write_lock_bh(&ifp->idev->lock);
                action = check_cleanup_prefix_route(ifp, &rt_expires);
                write_unlock_bh(&ifp->idev->lock);

                if (action != CLEANUP_PREFIX_RT_NOP) {
                        cleanup_prefix_route(ifp, rt_expires,
                                action == CLEANUP_PREFIX_RT_DEL, false);
                }
        }

        if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) {
                if (was_managetempaddr && !(ifp->flags & IFA_F_MANAGETEMPADDR))
                        delete_tempaddrs(ifp->idev, ifp);
                else
                        manage_tempaddrs(ifp->idev, ifp, cfg->valid_lft,
                                         cfg->preferred_lft, !was_managetempaddr,
                                         jiffies);
        }

        addrconf_verify_rtnl(net);

        return 0;
}

static int
inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
                  struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr *tb[IFA_MAX+1];
        struct in6_addr *peer_pfx;
        struct inet6_ifaddr *ifa;
        struct net_device *dev;
        struct inet6_dev *idev;
        struct ifa6_config cfg;
        struct ifaddrmsg *ifm;
        unsigned long timeout;
        clock_t expires;
        u32 flags;
        int err;

        err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
                                     ifa_ipv6_policy, extack);
        if (err < 0)
                return err;

        memset(&cfg, 0, sizeof(cfg));

        ifm = nlmsg_data(nlh);
        cfg.pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
        if (!cfg.pfx)
                return -EINVAL;

        cfg.peer_pfx = peer_pfx;
        cfg.plen = ifm->ifa_prefixlen;
        if (tb[IFA_RT_PRIORITY])
                cfg.rt_priority = nla_get_u32(tb[IFA_RT_PRIORITY]);

        if (tb[IFA_PROTO])
                cfg.ifa_proto = nla_get_u8(tb[IFA_PROTO]);

        cfg.ifa_flags = nla_get_u32_default(tb[IFA_FLAGS], ifm->ifa_flags);

        /* We ignore other flags so far. */
        cfg.ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS |
                         IFA_F_MANAGETEMPADDR | IFA_F_NOPREFIXROUTE |
                         IFA_F_MCAUTOJOIN | IFA_F_OPTIMISTIC;

        cfg.ifa_flags |= IFA_F_PERMANENT;
        cfg.valid_lft = INFINITY_LIFE_TIME;
        cfg.preferred_lft = INFINITY_LIFE_TIME;
        expires = 0;
        flags = 0;

        if (tb[IFA_CACHEINFO]) {
                struct ifa_cacheinfo *ci;

                ci = nla_data(tb[IFA_CACHEINFO]);
                cfg.valid_lft = ci->ifa_valid;
                cfg.preferred_lft = ci->ifa_prefered;

                if (!cfg.valid_lft || cfg.preferred_lft > cfg.valid_lft) {
                        NL_SET_ERR_MSG_MOD(extack, "address lifetime invalid");
                        return -EINVAL;
                }

                timeout = addrconf_timeout_fixup(cfg.valid_lft, HZ);
                if (addrconf_finite_timeout(timeout)) {
                        cfg.ifa_flags &= ~IFA_F_PERMANENT;
                        cfg.valid_lft = timeout;
                        expires = jiffies_to_clock_t(timeout * HZ);
                        flags = RTF_EXPIRES;
                }

                timeout = addrconf_timeout_fixup(cfg.preferred_lft, HZ);
                if (addrconf_finite_timeout(timeout)) {
                        if (timeout == 0)
                                cfg.ifa_flags |= IFA_F_DEPRECATED;

                        cfg.preferred_lft = timeout;
                }
        }

        rtnl_net_lock(net);

        dev =  __dev_get_by_index(net, ifm->ifa_index);
        if (!dev) {
                NL_SET_ERR_MSG_MOD(extack, "Unable to find the interface");
                err = -ENODEV;
                goto unlock_rtnl;
        }

        netdev_lock_ops(dev);
        idev = ipv6_find_idev(dev);
        if (IS_ERR(idev)) {
                err = PTR_ERR(idev);
                goto unlock;
        }

        if (!ipv6_allow_optimistic_dad(net, idev))
                cfg.ifa_flags &= ~IFA_F_OPTIMISTIC;

        if (cfg.ifa_flags & IFA_F_NODAD &&
            cfg.ifa_flags & IFA_F_OPTIMISTIC) {
                NL_SET_ERR_MSG(extack, "IFA_F_NODAD and IFA_F_OPTIMISTIC are mutually exclusive");
                err = -EINVAL;
                goto unlock;
        }

        ifa = ipv6_get_ifaddr(net, cfg.pfx, dev, 1);
        if (!ifa) {
                /*
                 * It would be best to check for !NLM_F_CREATE here but
                 * userspace already relies on not having to provide this.
                 */
                err = inet6_addr_add(net, dev, &cfg, expires, flags, extack);
                goto unlock;
        }

        if (nlh->nlmsg_flags & NLM_F_EXCL ||
            !(nlh->nlmsg_flags & NLM_F_REPLACE)) {
                NL_SET_ERR_MSG_MOD(extack, "address already assigned");
                err = -EEXIST;
        } else {
                err = inet6_addr_modify(net, ifa, &cfg, expires, flags);
        }

        in6_ifa_put(ifa);
unlock:
        netdev_unlock_ops(dev);
unlock_rtnl:
        rtnl_net_unlock(net);

        return err;
}

static void put_ifaddrmsg(struct nlmsghdr *nlh, u8 prefixlen, u32 flags,
                          u8 scope, int ifindex)
{
        struct ifaddrmsg *ifm;

        ifm = nlmsg_data(nlh);
        ifm->ifa_family = AF_INET6;
        ifm->ifa_prefixlen = prefixlen;
        ifm->ifa_flags = flags;
        ifm->ifa_scope = scope;
        ifm->ifa_index = ifindex;
}

static int put_cacheinfo(struct sk_buff *skb, unsigned long cstamp,
                         unsigned long tstamp, u32 preferred, u32 valid)
{
        struct ifa_cacheinfo ci;

        ci.cstamp = cstamp_delta(cstamp);
        ci.tstamp = cstamp_delta(tstamp);
        ci.ifa_prefered = preferred;
        ci.ifa_valid = valid;

        return nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci);
}

static inline int rt_scope(int ifa_scope)
{
        if (ifa_scope & IFA_HOST)
                return RT_SCOPE_HOST;
        else if (ifa_scope & IFA_LINK)
                return RT_SCOPE_LINK;
        else if (ifa_scope & IFA_SITE)
                return RT_SCOPE_SITE;
        else
                return RT_SCOPE_UNIVERSE;
}

static inline int inet6_ifaddr_msgsize(void)
{
        return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
               + nla_total_size(16) /* IFA_LOCAL */
               + nla_total_size(16) /* IFA_ADDRESS */
               + nla_total_size(sizeof(struct ifa_cacheinfo))
               + nla_total_size(4)  /* IFA_FLAGS */
               + nla_total_size(1)  /* IFA_PROTO */
               + nla_total_size(4)  /* IFA_RT_PRIORITY */;
}

static int inet6_fill_ifaddr(struct sk_buff *skb,
                             const struct inet6_ifaddr *ifa,
                             struct inet6_fill_args *args)
{
        struct nlmsghdr *nlh;
        u32 preferred, valid;
        u32 flags, priority;
        u8 proto;

        nlh = nlmsg_put(skb, args->portid, args->seq, args->event,
                        sizeof(struct ifaddrmsg), args->flags);
        if (!nlh)
                return -EMSGSIZE;

        flags = READ_ONCE(ifa->flags);
        put_ifaddrmsg(nlh, ifa->prefix_len, ifa->flags, rt_scope(ifa->scope),
                      ifa->idev->dev->ifindex);

        if (args->netnsid >= 0 &&
            nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid))
                goto error;

        preferred = READ_ONCE(ifa->prefered_lft);
        valid = READ_ONCE(ifa->valid_lft);

        if (!((flags & IFA_F_PERMANENT) &&
              (preferred == INFINITY_LIFE_TIME))) {
                if (preferred != INFINITY_LIFE_TIME) {
                        long tval = (jiffies - READ_ONCE(ifa->tstamp)) / HZ;

                        if (preferred > tval)
                                preferred -= tval;
                        else
                                preferred = 0;
                        if (valid != INFINITY_LIFE_TIME) {
                                if (valid > tval)
                                        valid -= tval;
                                else
                                        valid = 0;
                        }
                }
        } else {
                preferred = INFINITY_LIFE_TIME;
                valid = INFINITY_LIFE_TIME;
        }

        if (!ipv6_addr_any(&ifa->peer_addr)) {
                if (nla_put_in6_addr(skb, IFA_LOCAL, &ifa->addr) < 0 ||
                    nla_put_in6_addr(skb, IFA_ADDRESS, &ifa->peer_addr) < 0)
                        goto error;
        } else {
                if (nla_put_in6_addr(skb, IFA_ADDRESS, &ifa->addr) < 0)
                        goto error;
        }

        priority = READ_ONCE(ifa->rt_priority);
        if (priority && nla_put_u32(skb, IFA_RT_PRIORITY, priority))
                goto error;

        if (put_cacheinfo(skb, ifa->cstamp, READ_ONCE(ifa->tstamp),
                          preferred, valid) < 0)
                goto error;

        if (nla_put_u32(skb, IFA_FLAGS, flags) < 0)
                goto error;

        proto = READ_ONCE(ifa->ifa_proto);
        if (proto && nla_put_u8(skb, IFA_PROTO, proto))
                goto error;

        nlmsg_end(skb, nlh);
        return 0;

error:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

int inet6_fill_ifmcaddr(struct sk_buff *skb,
                        const struct ifmcaddr6 *ifmca,
                        struct inet6_fill_args *args)
{
        int ifindex = ifmca->idev->dev->ifindex;
        u8 scope = RT_SCOPE_UNIVERSE;
        struct nlmsghdr *nlh;

        if (!args->force_rt_scope_universe &&
            ipv6_addr_scope(&ifmca->mca_addr) & IFA_SITE)
                scope = RT_SCOPE_SITE;

        nlh = nlmsg_put(skb, args->portid, args->seq, args->event,
                        sizeof(struct ifaddrmsg), args->flags);
        if (!nlh)
                return -EMSGSIZE;

        if (args->netnsid >= 0 &&
            nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid)) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
        if (nla_put_in6_addr(skb, IFA_MULTICAST, &ifmca->mca_addr) < 0 ||
            put_cacheinfo(skb, ifmca->mca_cstamp, READ_ONCE(ifmca->mca_tstamp),
                          INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        nlmsg_end(skb, nlh);
        return 0;
}

int inet6_fill_ifacaddr(struct sk_buff *skb,
                        const struct ifacaddr6 *ifaca,
                        struct inet6_fill_args *args)
{
        struct net_device *dev = fib6_info_nh_dev(ifaca->aca_rt);
        int ifindex = dev ? dev->ifindex : 1;
        u8 scope = RT_SCOPE_UNIVERSE;
        struct nlmsghdr *nlh;

        if (ipv6_addr_scope(&ifaca->aca_addr) & IFA_SITE)
                scope = RT_SCOPE_SITE;

        nlh = nlmsg_put(skb, args->portid, args->seq, args->event,
                        sizeof(struct ifaddrmsg), args->flags);
        if (!nlh)
                return -EMSGSIZE;

        if (args->netnsid >= 0 &&
            nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid)) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
        if (nla_put_in6_addr(skb, IFA_ANYCAST, &ifaca->aca_addr) < 0 ||
            put_cacheinfo(skb, ifaca->aca_cstamp, READ_ONCE(ifaca->aca_tstamp),
                          INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
                nlmsg_cancel(skb, nlh);
                return -EMSGSIZE;
        }

        nlmsg_end(skb, nlh);
        return 0;
}

/* called with rcu_read_lock() */
static int in6_dump_addrs(const struct inet6_dev *idev, struct sk_buff *skb,
                          struct netlink_callback *cb, int *s_ip_idx,
                          struct inet6_fill_args *fillargs)
{
        const struct ifmcaddr6 *ifmca;
        const struct ifacaddr6 *ifaca;
        int ip_idx = 0;
        int err = 0;

        switch (fillargs->type) {
        case UNICAST_ADDR: {
                const struct inet6_ifaddr *ifa;
                fillargs->event = RTM_NEWADDR;

                /* unicast address incl. temp addr */
                list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
                        if (ip_idx < *s_ip_idx)
                                goto next;
                        err = inet6_fill_ifaddr(skb, ifa, fillargs);
                        if (err < 0)
                                break;
                        nl_dump_check_consistent(cb, nlmsg_hdr(skb));
next:
                        ip_idx++;
                }
                break;
        }
        case MULTICAST_ADDR:
                fillargs->event = RTM_GETMULTICAST;

                /* multicast address */
                for (ifmca = rcu_dereference(idev->mc_list);
                     ifmca;
                     ifmca = rcu_dereference(ifmca->next), ip_idx++) {
                        if (ip_idx < *s_ip_idx)
                                continue;
                        err = inet6_fill_ifmcaddr(skb, ifmca, fillargs);
                        if (err < 0)
                                break;
                }
                break;
        case ANYCAST_ADDR:
                fillargs->event = RTM_GETANYCAST;
                /* anycast address */
                for (ifaca = rcu_dereference(idev->ac_list); ifaca;
                     ifaca = rcu_dereference(ifaca->aca_next), ip_idx++) {
                        if (ip_idx < *s_ip_idx)
                                continue;
                        err = inet6_fill_ifacaddr(skb, ifaca, fillargs);
                        if (err < 0)
                                break;
                }
                break;
        default:
                break;
        }
        *s_ip_idx = err ? ip_idx : 0;
        return err;
}

static int inet6_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                                       struct inet6_fill_args *fillargs,
                                       struct net **tgt_net, struct sock *sk,
                                       struct netlink_callback *cb)
{
        struct netlink_ext_ack *extack = cb->extack;
        struct nlattr *tb[IFA_MAX+1];
        struct ifaddrmsg *ifm;
        int err, i;

        ifm = nlmsg_payload(nlh, sizeof(*ifm));
        if (!ifm) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid header for address dump request");
                return -EINVAL;
        }

        if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address dump request");
                return -EINVAL;
        }

        fillargs->ifindex = ifm->ifa_index;
        if (fillargs->ifindex) {
                cb->answer_flags |= NLM_F_DUMP_FILTERED;
                fillargs->flags |= NLM_F_DUMP_FILTERED;
        }

        err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifm), tb, IFA_MAX,
                                            ifa_ipv6_policy, extack);
        if (err < 0)
                return err;

        for (i = 0; i <= IFA_MAX; ++i) {
                if (!tb[i])
                        continue;

                if (i == IFA_TARGET_NETNSID) {
                        struct net *net;

                        fillargs->netnsid = nla_get_s32(tb[i]);
                        net = rtnl_get_net_ns_capable(sk, fillargs->netnsid);
                        if (IS_ERR(net)) {
                                fillargs->netnsid = -1;
                                NL_SET_ERR_MSG_MOD(extack, "Invalid target network namespace id");
                                return PTR_ERR(net);
                        }
                        *tgt_net = net;
                } else {
                        NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in dump request");
                        return -EINVAL;
                }
        }

        return 0;
}

static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
                           enum addr_type_t type)
{
        struct net *tgt_net = sock_net(skb->sk);
        const struct nlmsghdr *nlh = cb->nlh;
        struct inet6_fill_args fillargs = {
                .portid = NETLINK_CB(cb->skb).portid,
                .seq = cb->nlh->nlmsg_seq,
                .flags = NLM_F_MULTI,
                .netnsid = -1,
                .type = type,
                .force_rt_scope_universe = false,
        };
        struct {
                unsigned long ifindex;
                int ip_idx;
        } *ctx = (void *)cb->ctx;
        struct net_device *dev;
        struct inet6_dev *idev;
        int err = 0;

        rcu_read_lock();
        if (cb->strict_check) {
                err = inet6_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net,
                                                  skb->sk, cb);
                if (err < 0)
                        goto done;

                err = 0;
                if (fillargs.ifindex) {
                        dev = dev_get_by_index_rcu(tgt_net, fillargs.ifindex);
                        if (!dev) {
                                err = -ENODEV;
                                goto done;
                        }
                        idev = __in6_dev_get(dev);
                        if (idev)
                                err = in6_dump_addrs(idev, skb, cb,
                                                     &ctx->ip_idx,
                                                     &fillargs);
                        goto done;
                }
        }

        cb->seq = inet6_base_seq(tgt_net);
        for_each_netdev_dump(tgt_net, dev, ctx->ifindex) {
                idev = __in6_dev_get(dev);
                if (!idev)
                        continue;
                err = in6_dump_addrs(idev, skb, cb, &ctx->ip_idx,
                                     &fillargs);
                if (err < 0)
                        goto done;
        }
done:
        rcu_read_unlock();
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);

        return err;
}

static int inet6_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
        enum addr_type_t type = UNICAST_ADDR;

        return inet6_dump_addr(skb, cb, type);
}

static int inet6_dump_ifmcaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
        enum addr_type_t type = MULTICAST_ADDR;

        return inet6_dump_addr(skb, cb, type);
}


static int inet6_dump_ifacaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
        enum addr_type_t type = ANYCAST_ADDR;

        return inet6_dump_addr(skb, cb, type);
}

static int inet6_rtm_valid_getaddr_req(struct sk_buff *skb,
                                       const struct nlmsghdr *nlh,
                                       struct nlattr **tb,
                                       struct netlink_ext_ack *extack)
{
        struct ifaddrmsg *ifm;
        int i, err;

        ifm = nlmsg_payload(nlh, sizeof(*ifm));
        if (!ifm) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid header for get address request");
                return -EINVAL;
        }

        if (!netlink_strict_get_check(skb))
                return nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
                                              ifa_ipv6_policy, extack);

        if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get address request");
                return -EINVAL;
        }

        err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifm), tb, IFA_MAX,
                                            ifa_ipv6_policy, extack);
        if (err)
                return err;

        for (i = 0; i <= IFA_MAX; i++) {
                if (!tb[i])
                        continue;

                switch (i) {
                case IFA_TARGET_NETNSID:
                case IFA_ADDRESS:
                case IFA_LOCAL:
                        break;
                default:
                        NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get address request");
                        return -EINVAL;
                }
        }

        return 0;
}

static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh,
                             struct netlink_ext_ack *extack)
{
        struct net *tgt_net = sock_net(in_skb->sk);
        struct inet6_fill_args fillargs = {
                .portid = NETLINK_CB(in_skb).portid,
                .seq = nlh->nlmsg_seq,
                .event = RTM_NEWADDR,
                .flags = 0,
                .netnsid = -1,
                .force_rt_scope_universe = false,
        };
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
        struct in6_addr *addr = NULL, *peer;
        struct net_device *dev = NULL;
        struct inet6_ifaddr *ifa;
        struct sk_buff *skb;
        int err;

        err = inet6_rtm_valid_getaddr_req(in_skb, nlh, tb, extack);
        if (err < 0)
                return err;

        if (tb[IFA_TARGET_NETNSID]) {
                fillargs.netnsid = nla_get_s32(tb[IFA_TARGET_NETNSID]);

                tgt_net = rtnl_get_net_ns_capable(NETLINK_CB(in_skb).sk,
                                                  fillargs.netnsid);
                if (IS_ERR(tgt_net))
                        return PTR_ERR(tgt_net);
        }

        addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer);
        if (!addr) {
                err = -EINVAL;
                goto errout;
        }
        ifm = nlmsg_data(nlh);
        if (ifm->ifa_index)
                dev = dev_get_by_index(tgt_net, ifm->ifa_index);

        ifa = ipv6_get_ifaddr(tgt_net, addr, dev, 1);
        if (!ifa) {
                err = -EADDRNOTAVAIL;
                goto errout;
        }

        skb = nlmsg_new(inet6_ifaddr_msgsize(), GFP_KERNEL);
        if (!skb) {
                err = -ENOBUFS;
                goto errout_ifa;
        }

        err = inet6_fill_ifaddr(skb, ifa, &fillargs);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout_ifa;
        }
        err = rtnl_unicast(skb, tgt_net, NETLINK_CB(in_skb).portid);
errout_ifa:
        in6_ifa_put(ifa);
errout:
        dev_put(dev);
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);

        return err;
}

static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa)
{
        struct sk_buff *skb;
        struct net *net = dev_net(ifa->idev->dev);
        struct inet6_fill_args fillargs = {
                .portid = 0,
                .seq = 0,
                .event = event,
                .flags = 0,
                .netnsid = -1,
                .force_rt_scope_universe = false,
        };
        int err = -ENOBUFS;

        skb = nlmsg_new(inet6_ifaddr_msgsize(), GFP_ATOMIC);
        if (!skb)
                goto errout;

        err = inet6_fill_ifaddr(skb, ifa, &fillargs);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFADDR, NULL, GFP_ATOMIC);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_IPV6_IFADDR, err);
}

static void ipv6_store_devconf(const struct ipv6_devconf *cnf,
                               __s32 *array, int bytes)
{
        BUG_ON(bytes < (DEVCONF_MAX * 4));

        memset(array, 0, bytes);
        array[DEVCONF_FORWARDING] = READ_ONCE(cnf->forwarding);
        array[DEVCONF_HOPLIMIT] = READ_ONCE(cnf->hop_limit);
        array[DEVCONF_MTU6] = READ_ONCE(cnf->mtu6);
        array[DEVCONF_ACCEPT_RA] = READ_ONCE(cnf->accept_ra);
        array[DEVCONF_ACCEPT_REDIRECTS] = READ_ONCE(cnf->accept_redirects);
        array[DEVCONF_AUTOCONF] = READ_ONCE(cnf->autoconf);
        array[DEVCONF_DAD_TRANSMITS] = READ_ONCE(cnf->dad_transmits);
        array[DEVCONF_RTR_SOLICITS] = READ_ONCE(cnf->rtr_solicits);
        array[DEVCONF_RTR_SOLICIT_INTERVAL] =
                jiffies_to_msecs(READ_ONCE(cnf->rtr_solicit_interval));
        array[DEVCONF_RTR_SOLICIT_MAX_INTERVAL] =
                jiffies_to_msecs(READ_ONCE(cnf->rtr_solicit_max_interval));
        array[DEVCONF_RTR_SOLICIT_DELAY] =
                jiffies_to_msecs(READ_ONCE(cnf->rtr_solicit_delay));
        array[DEVCONF_FORCE_MLD_VERSION] = READ_ONCE(cnf->force_mld_version);
        array[DEVCONF_MLDV1_UNSOLICITED_REPORT_INTERVAL] =
                jiffies_to_msecs(READ_ONCE(cnf->mldv1_unsolicited_report_interval));
        array[DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL] =
                jiffies_to_msecs(READ_ONCE(cnf->mldv2_unsolicited_report_interval));
        array[DEVCONF_USE_TEMPADDR] = READ_ONCE(cnf->use_tempaddr);
        array[DEVCONF_TEMP_VALID_LFT] = READ_ONCE(cnf->temp_valid_lft);
        array[DEVCONF_TEMP_PREFERED_LFT] = READ_ONCE(cnf->temp_prefered_lft);
        array[DEVCONF_REGEN_MAX_RETRY] = READ_ONCE(cnf->regen_max_retry);
        array[DEVCONF_MAX_DESYNC_FACTOR] = READ_ONCE(cnf->max_desync_factor);
        array[DEVCONF_MAX_ADDRESSES] = READ_ONCE(cnf->max_addresses);
        array[DEVCONF_ACCEPT_RA_DEFRTR] = READ_ONCE(cnf->accept_ra_defrtr);
        array[DEVCONF_RA_DEFRTR_METRIC] = READ_ONCE(cnf->ra_defrtr_metric);
        array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] =
                READ_ONCE(cnf->accept_ra_min_hop_limit);
        array[DEVCONF_ACCEPT_RA_PINFO] = READ_ONCE(cnf->accept_ra_pinfo);
#ifdef CONFIG_IPV6_ROUTER_PREF
        array[DEVCONF_ACCEPT_RA_RTR_PREF] = READ_ONCE(cnf->accept_ra_rtr_pref);
        array[DEVCONF_RTR_PROBE_INTERVAL] =
                jiffies_to_msecs(READ_ONCE(cnf->rtr_probe_interval));
#ifdef CONFIG_IPV6_ROUTE_INFO
        array[DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN] =
                READ_ONCE(cnf->accept_ra_rt_info_min_plen);
        array[DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN] =
                READ_ONCE(cnf->accept_ra_rt_info_max_plen);
#endif
#endif
        array[DEVCONF_PROXY_NDP] = READ_ONCE(cnf->proxy_ndp);
        array[DEVCONF_ACCEPT_SOURCE_ROUTE] =
                READ_ONCE(cnf->accept_source_route);
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        array[DEVCONF_OPTIMISTIC_DAD] = READ_ONCE(cnf->optimistic_dad);
        array[DEVCONF_USE_OPTIMISTIC] = READ_ONCE(cnf->use_optimistic);
#endif
#ifdef CONFIG_IPV6_MROUTE
        array[DEVCONF_MC_FORWARDING] = atomic_read(&cnf->mc_forwarding);
#endif
        array[DEVCONF_DISABLE_IPV6] = READ_ONCE(cnf->disable_ipv6);
        array[DEVCONF_ACCEPT_DAD] = READ_ONCE(cnf->accept_dad);
        array[DEVCONF_FORCE_TLLAO] = READ_ONCE(cnf->force_tllao);
        array[DEVCONF_NDISC_NOTIFY] = READ_ONCE(cnf->ndisc_notify);
        array[DEVCONF_SUPPRESS_FRAG_NDISC] =
                READ_ONCE(cnf->suppress_frag_ndisc);
        array[DEVCONF_ACCEPT_RA_FROM_LOCAL] =
                READ_ONCE(cnf->accept_ra_from_local);
        array[DEVCONF_ACCEPT_RA_MTU] = READ_ONCE(cnf->accept_ra_mtu);
        array[DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN] =
                READ_ONCE(cnf->ignore_routes_with_linkdown);
        /* we omit DEVCONF_STABLE_SECRET for now */
        array[DEVCONF_USE_OIF_ADDRS_ONLY] = READ_ONCE(cnf->use_oif_addrs_only);
        array[DEVCONF_DROP_UNICAST_IN_L2_MULTICAST] =
                READ_ONCE(cnf->drop_unicast_in_l2_multicast);
        array[DEVCONF_DROP_UNSOLICITED_NA] = READ_ONCE(cnf->drop_unsolicited_na);
        array[DEVCONF_KEEP_ADDR_ON_DOWN] = READ_ONCE(cnf->keep_addr_on_down);
        array[DEVCONF_SEG6_ENABLED] = READ_ONCE(cnf->seg6_enabled);
#ifdef CONFIG_IPV6_SEG6_HMAC
        array[DEVCONF_SEG6_REQUIRE_HMAC] = READ_ONCE(cnf->seg6_require_hmac);
#endif
        array[DEVCONF_ENHANCED_DAD] = READ_ONCE(cnf->enhanced_dad);
        array[DEVCONF_ADDR_GEN_MODE] = READ_ONCE(cnf->addr_gen_mode);
        array[DEVCONF_DISABLE_POLICY] = READ_ONCE(cnf->disable_policy);
        array[DEVCONF_NDISC_TCLASS] = READ_ONCE(cnf->ndisc_tclass);
        array[DEVCONF_RPL_SEG_ENABLED] = READ_ONCE(cnf->rpl_seg_enabled);
        array[DEVCONF_IOAM6_ENABLED] = READ_ONCE(cnf->ioam6_enabled);
        array[DEVCONF_IOAM6_ID] = READ_ONCE(cnf->ioam6_id);
        array[DEVCONF_IOAM6_ID_WIDE] = READ_ONCE(cnf->ioam6_id_wide);
        array[DEVCONF_NDISC_EVICT_NOCARRIER] =
                READ_ONCE(cnf->ndisc_evict_nocarrier);
        array[DEVCONF_ACCEPT_UNTRACKED_NA] =
                READ_ONCE(cnf->accept_untracked_na);
        array[DEVCONF_ACCEPT_RA_MIN_LFT] = READ_ONCE(cnf->accept_ra_min_lft);
        array[DEVCONF_FORCE_FORWARDING] = READ_ONCE(cnf->force_forwarding);
}

static inline size_t inet6_ifla6_size(void)
{
        return nla_total_size(4) /* IFLA_INET6_FLAGS */
             + nla_total_size(sizeof(struct ifla_cacheinfo))
             + nla_total_size(DEVCONF_MAX * 4) /* IFLA_INET6_CONF */
             + nla_total_size(IPSTATS_MIB_MAX * 8) /* IFLA_INET6_STATS */
             + nla_total_size(ICMP6_MIB_MAX * 8) /* IFLA_INET6_ICMP6STATS */
             + nla_total_size(sizeof(struct in6_addr)) /* IFLA_INET6_TOKEN */
             + nla_total_size(1) /* IFLA_INET6_ADDR_GEN_MODE */
             + nla_total_size(4) /* IFLA_INET6_RA_MTU */
             + 0;
}

static inline size_t inet6_if_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct ifinfomsg))
               + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
               + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
               + nla_total_size(4) /* IFLA_MTU */
               + nla_total_size(4) /* IFLA_LINK */
               + nla_total_size(1) /* IFLA_OPERSTATE */
               + nla_total_size(inet6_ifla6_size()); /* IFLA_PROTINFO */
}

static inline void __snmp6_fill_statsdev(u64 *stats, atomic_long_t *mib,
                                        int bytes)
{
        int i;
        int pad = bytes - sizeof(u64) * ICMP6_MIB_MAX;
        BUG_ON(pad < 0);

        /* Use put_unaligned() because stats may not be aligned for u64. */
        put_unaligned(ICMP6_MIB_MAX, &stats[0]);
        for (i = 1; i < ICMP6_MIB_MAX; i++)
                put_unaligned(atomic_long_read(&mib[i]), &stats[i]);

        memset(&stats[ICMP6_MIB_MAX], 0, pad);
}

static inline void __snmp6_fill_stats64(u64 *stats, void __percpu *mib,
                                        int bytes, size_t syncpoff)
{
        int i, c;
        u64 buff[IPSTATS_MIB_MAX];
        int pad = bytes - sizeof(u64) * IPSTATS_MIB_MAX;

        BUG_ON(pad < 0);

        memset(buff, 0, sizeof(buff));
        buff[0] = IPSTATS_MIB_MAX;

        for_each_possible_cpu(c) {
                for (i = 1; i < IPSTATS_MIB_MAX; i++)
                        buff[i] += snmp_get_cpu_field64(mib, c, i, syncpoff);
        }

        memcpy(stats, buff, IPSTATS_MIB_MAX * sizeof(u64));
        memset(&stats[IPSTATS_MIB_MAX], 0, pad);
}

static void snmp6_fill_stats(u64 *stats, struct inet6_dev *idev, int attrtype,
                             int bytes)
{
        switch (attrtype) {
        case IFLA_INET6_STATS:
                __snmp6_fill_stats64(stats, idev->stats.ipv6, bytes,
                                     offsetof(struct ipstats_mib, syncp));
                break;
        case IFLA_INET6_ICMP6STATS:
                __snmp6_fill_statsdev(stats, idev->stats.icmpv6dev->mibs, bytes);
                break;
        }
}

static int inet6_fill_ifla6_stats_attrs(struct sk_buff *skb,
                                        struct inet6_dev *idev)
{
        struct nlattr *nla;

        nla = nla_reserve(skb, IFLA_INET6_STATS, IPSTATS_MIB_MAX * sizeof(u64));
        if (!nla)
                goto nla_put_failure;
        snmp6_fill_stats(nla_data(nla), idev, IFLA_INET6_STATS, nla_len(nla));

        nla = nla_reserve(skb, IFLA_INET6_ICMP6STATS, ICMP6_MIB_MAX * sizeof(u64));
        if (!nla)
                goto nla_put_failure;
        snmp6_fill_stats(nla_data(nla), idev, IFLA_INET6_ICMP6STATS, nla_len(nla));

        return 0;

nla_put_failure:
        return -EMSGSIZE;
}

static int inet6_fill_ifla6_attrs(struct sk_buff *skb, struct inet6_dev *idev,
                                  u32 ext_filter_mask)
{
        struct ifla_cacheinfo ci;
        struct nlattr *nla;
        u32 ra_mtu;

        if (nla_put_u32(skb, IFLA_INET6_FLAGS, READ_ONCE(idev->if_flags)))
                goto nla_put_failure;
        ci.max_reasm_len = IPV6_MAXPLEN;
        ci.tstamp = cstamp_delta(READ_ONCE(idev->tstamp));
        ci.reachable_time = jiffies_to_msecs(idev->nd_parms->reachable_time);
        ci.retrans_time = jiffies_to_msecs(NEIGH_VAR(idev->nd_parms, RETRANS_TIME));
        if (nla_put(skb, IFLA_INET6_CACHEINFO, sizeof(ci), &ci))
                goto nla_put_failure;
        nla = nla_reserve(skb, IFLA_INET6_CONF, DEVCONF_MAX * sizeof(s32));
        if (!nla)
                goto nla_put_failure;
        ipv6_store_devconf(&idev->cnf, nla_data(nla), nla_len(nla));

        /* XXX - MC not implemented */

        if (!(ext_filter_mask & RTEXT_FILTER_SKIP_STATS)) {
                if (inet6_fill_ifla6_stats_attrs(skb, idev) < 0)
                        goto nla_put_failure;
        }

        nla = nla_reserve(skb, IFLA_INET6_TOKEN, sizeof(struct in6_addr));
        if (!nla)
                goto nla_put_failure;
        read_lock_bh(&idev->lock);
        memcpy(nla_data(nla), idev->token.s6_addr, nla_len(nla));
        read_unlock_bh(&idev->lock);

        if (nla_put_u8(skb, IFLA_INET6_ADDR_GEN_MODE,
                       READ_ONCE(idev->cnf.addr_gen_mode)))
                goto nla_put_failure;

        ra_mtu = READ_ONCE(idev->ra_mtu);
        if (ra_mtu && nla_put_u32(skb, IFLA_INET6_RA_MTU, ra_mtu))
                goto nla_put_failure;

        return 0;

nla_put_failure:
        return -EMSGSIZE;
}

static size_t inet6_get_link_af_size(const struct net_device *dev,
                                     u32 ext_filter_mask)
{
        if (!__in6_dev_get(dev))
                return 0;

        return inet6_ifla6_size();
}

static int inet6_fill_link_af(struct sk_buff *skb, const struct net_device *dev,
                              u32 ext_filter_mask)
{
        struct inet6_dev *idev = __in6_dev_get(dev);

        if (!idev)
                return -ENODATA;

        if (inet6_fill_ifla6_attrs(skb, idev, ext_filter_mask) < 0)
                return -EMSGSIZE;

        return 0;
}

static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token,
                             struct netlink_ext_ack *extack)
{
        struct inet6_ifaddr *ifp;
        struct net_device *dev = idev->dev;
        bool clear_token, update_rs = false;
        struct in6_addr ll_addr;

        ASSERT_RTNL();

        if (!token)
                return -EINVAL;

        if (dev->flags & IFF_LOOPBACK) {
                NL_SET_ERR_MSG_MOD(extack, "Device is loopback");
                return -EINVAL;
        }

        if (dev->flags & IFF_NOARP) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Device does not do neighbour discovery");
                return -EINVAL;
        }

        if (!ipv6_accept_ra(idev)) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Router advertisement is disabled on device");
                return -EINVAL;
        }

        if (READ_ONCE(idev->cnf.rtr_solicits) == 0) {
                NL_SET_ERR_MSG(extack,
                               "Router solicitation is disabled on device");
                return -EINVAL;
        }

        write_lock_bh(&idev->lock);

        BUILD_BUG_ON(sizeof(token->s6_addr) != 16);
        memcpy(idev->token.s6_addr + 8, token->s6_addr + 8, 8);

        write_unlock_bh(&idev->lock);

        clear_token = ipv6_addr_any(token);
        if (clear_token)
                goto update_lft;

        if (!idev->dead && (idev->if_flags & IF_READY) &&
            !ipv6_get_lladdr(dev, &ll_addr, IFA_F_TENTATIVE |
                             IFA_F_OPTIMISTIC)) {
                /* If we're not ready, then normal ifup will take care
                 * of this. Otherwise, we need to request our rs here.
                 */
                ndisc_send_rs(dev, &ll_addr, &in6addr_linklocal_allrouters);
                update_rs = true;
        }

update_lft:
        write_lock_bh(&idev->lock);

        if (update_rs) {
                idev->if_flags |= IF_RS_SENT;
                idev->rs_interval = rfc3315_s14_backoff_init(
                        READ_ONCE(idev->cnf.rtr_solicit_interval));
                idev->rs_probes = 1;
                addrconf_mod_rs_timer(idev, idev->rs_interval);
        }

        /* Well, that's kinda nasty ... */
        list_for_each_entry(ifp, &idev->addr_list, if_list) {
                spin_lock(&ifp->lock);
                if (ifp->tokenized) {
                        ifp->valid_lft = 0;
                        ifp->prefered_lft = 0;
                }
                spin_unlock(&ifp->lock);
        }

        write_unlock_bh(&idev->lock);
        inet6_ifinfo_notify(RTM_NEWLINK, idev);
        addrconf_verify_rtnl(dev_net(dev));
        return 0;
}

static const struct nla_policy inet6_af_policy[IFLA_INET6_MAX + 1] = {
        [IFLA_INET6_ADDR_GEN_MODE]      = { .type = NLA_U8 },
        [IFLA_INET6_TOKEN]              = { .len = sizeof(struct in6_addr) },
        [IFLA_INET6_RA_MTU]             = { .type = NLA_REJECT,
                                            .reject_message =
                                                "IFLA_INET6_RA_MTU can not be set" },
};

static int check_addr_gen_mode(int mode)
{
        if (mode != IN6_ADDR_GEN_MODE_EUI64 &&
            mode != IN6_ADDR_GEN_MODE_NONE &&
            mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
            mode != IN6_ADDR_GEN_MODE_RANDOM)
                return -EINVAL;
        return 1;
}

static int check_stable_privacy(struct inet6_dev *idev, struct net *net,
                                int mode)
{
        if (mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
            !idev->cnf.stable_secret.initialized &&
            !net->ipv6.devconf_dflt->stable_secret.initialized)
                return -EINVAL;
        return 1;
}

static int inet6_validate_link_af(const struct net_device *dev,
                                  const struct nlattr *nla,
                                  struct netlink_ext_ack *extack)
{
        struct nlattr *tb[IFLA_INET6_MAX + 1];
        struct inet6_dev *idev = NULL;
        int err;

        if (dev) {
                idev = __in6_dev_get(dev);
                if (!idev)
                        return -EAFNOSUPPORT;
        }

        err = nla_parse_nested_deprecated(tb, IFLA_INET6_MAX, nla,
                                          inet6_af_policy, extack);
        if (err)
                return err;

        if (!tb[IFLA_INET6_TOKEN] && !tb[IFLA_INET6_ADDR_GEN_MODE])
                return -EINVAL;

        if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
                u8 mode = nla_get_u8(tb[IFLA_INET6_ADDR_GEN_MODE]);

                if (check_addr_gen_mode(mode) < 0)
                        return -EINVAL;
                if (dev && check_stable_privacy(idev, dev_net(dev), mode) < 0)
                        return -EINVAL;
        }

        return 0;
}

static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla,
                             struct netlink_ext_ack *extack)
{
        struct inet6_dev *idev = __in6_dev_get(dev);
        struct nlattr *tb[IFLA_INET6_MAX + 1];
        int err;

        if (!idev)
                return -EAFNOSUPPORT;

        if (nla_parse_nested_deprecated(tb, IFLA_INET6_MAX, nla, NULL, NULL) < 0)
                return -EINVAL;

        if (tb[IFLA_INET6_TOKEN]) {
                err = inet6_set_iftoken(idev, nla_data(tb[IFLA_INET6_TOKEN]),
                                        extack);
                if (err)
                        return err;
        }

        if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
                u8 mode = nla_get_u8(tb[IFLA_INET6_ADDR_GEN_MODE]);

                WRITE_ONCE(idev->cnf.addr_gen_mode, mode);
        }

        return 0;
}

static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
                             u32 portid, u32 seq, int event, unsigned int flags)
{
        struct net_device *dev = idev->dev;
        struct ifinfomsg *hdr;
        struct nlmsghdr *nlh;
        int ifindex, iflink;
        void *protoinfo;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
        if (!nlh)
                return -EMSGSIZE;

        hdr = nlmsg_data(nlh);
        hdr->ifi_family = AF_INET6;
        hdr->__ifi_pad = 0;
        hdr->ifi_type = dev->type;
        ifindex = READ_ONCE(dev->ifindex);
        hdr->ifi_index = ifindex;
        hdr->ifi_flags = netif_get_flags(dev);
        hdr->ifi_change = 0;

        iflink = dev_get_iflink(dev);
        if (nla_put_string(skb, IFLA_IFNAME, dev->name) ||
            (dev->addr_len &&
             nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr)) ||
            nla_put_u32(skb, IFLA_MTU, READ_ONCE(dev->mtu)) ||
            (ifindex != iflink &&
             nla_put_u32(skb, IFLA_LINK, iflink)) ||
            nla_put_u8(skb, IFLA_OPERSTATE,
                       netif_running(dev) ? READ_ONCE(dev->operstate) : IF_OPER_DOWN))
                goto nla_put_failure;
        protoinfo = nla_nest_start_noflag(skb, IFLA_PROTINFO);
        if (!protoinfo)
                goto nla_put_failure;

        if (inet6_fill_ifla6_attrs(skb, idev, 0) < 0)
                goto nla_put_failure;

        nla_nest_end(skb, protoinfo);
        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static int inet6_valid_dump_ifinfo(const struct nlmsghdr *nlh,
                                   struct netlink_ext_ack *extack)
{
        struct ifinfomsg *ifm;

        ifm = nlmsg_payload(nlh, sizeof(*ifm));
        if (!ifm) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid header for link dump request");
                return -EINVAL;
        }

        if (nlmsg_attrlen(nlh, sizeof(*ifm))) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid data after header");
                return -EINVAL;
        }

        if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
            ifm->ifi_change || ifm->ifi_index) {
                NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for dump request");
                return -EINVAL;
        }

        return 0;
}

static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        struct {
                unsigned long ifindex;
        } *ctx = (void *)cb->ctx;
        struct net_device *dev;
        struct inet6_dev *idev;
        int err;

        /* only requests using strict checking can pass data to
         * influence the dump
         */
        if (cb->strict_check) {
                err = inet6_valid_dump_ifinfo(cb->nlh, cb->extack);

                if (err < 0)
                        return err;
        }

        err = 0;
        rcu_read_lock();
        for_each_netdev_dump(net, dev, ctx->ifindex) {
                idev = __in6_dev_get(dev);
                if (!idev)
                        continue;
                err = inet6_fill_ifinfo(skb, idev,
                                        NETLINK_CB(cb->skb).portid,
                                        cb->nlh->nlmsg_seq,
                                        RTM_NEWLINK, NLM_F_MULTI);
                if (err < 0)
                        break;
        }
        rcu_read_unlock();

        return err;
}

void inet6_ifinfo_notify(int event, struct inet6_dev *idev)
{
        struct sk_buff *skb;
        struct net *net = dev_net(idev->dev);
        int err = -ENOBUFS;

        skb = nlmsg_new(inet6_if_nlmsg_size(), GFP_ATOMIC);
        if (!skb)
                goto errout;

        err = inet6_fill_ifinfo(skb, idev, 0, 0, event, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_if_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFINFO, NULL, GFP_ATOMIC);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_IPV6_IFINFO, err);
}

static inline size_t inet6_prefix_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct prefixmsg))
               + nla_total_size(sizeof(struct in6_addr))
               + nla_total_size(sizeof(struct prefix_cacheinfo));
}

static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev,
                             struct prefix_info *pinfo, u32 portid, u32 seq,
                             int event, unsigned int flags)
{
        struct prefixmsg *pmsg;
        struct nlmsghdr *nlh;
        struct prefix_cacheinfo ci;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*pmsg), flags);
        if (!nlh)
                return -EMSGSIZE;

        pmsg = nlmsg_data(nlh);
        pmsg->prefix_family = AF_INET6;
        pmsg->prefix_pad1 = 0;
        pmsg->prefix_pad2 = 0;
        pmsg->prefix_ifindex = idev->dev->ifindex;
        pmsg->prefix_len = pinfo->prefix_len;
        pmsg->prefix_type = pinfo->type;
        pmsg->prefix_pad3 = 0;
        pmsg->prefix_flags = pinfo->flags;

        if (nla_put(skb, PREFIX_ADDRESS, sizeof(pinfo->prefix), &pinfo->prefix))
                goto nla_put_failure;
        ci.preferred_time = ntohl(pinfo->prefered);
        ci.valid_time = ntohl(pinfo->valid);
        if (nla_put(skb, PREFIX_CACHEINFO, sizeof(ci), &ci))
                goto nla_put_failure;
        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static void inet6_prefix_notify(int event, struct inet6_dev *idev,
                         struct prefix_info *pinfo)
{
        struct sk_buff *skb;
        struct net *net = dev_net(idev->dev);
        int err = -ENOBUFS;

        skb = nlmsg_new(inet6_prefix_nlmsg_size(), GFP_ATOMIC);
        if (!skb)
                goto errout;

        err = inet6_fill_prefix(skb, idev, pinfo, 0, 0, event, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet6_prefix_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV6_PREFIX, NULL, GFP_ATOMIC);
        return;
errout:
        rtnl_set_sk_err(net, RTNLGRP_IPV6_PREFIX, err);
}

static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
{
        struct net *net = dev_net(ifp->idev->dev);

        if (event)
                ASSERT_RTNL();

        inet6_ifa_notify(event ? : RTM_NEWADDR, ifp);

        switch (event) {
        case RTM_NEWADDR:
                /*
                 * If the address was optimistic we inserted the route at the
                 * start of our DAD process, so we don't need to do it again.
                 * If the device was taken down in the middle of the DAD
                 * cycle there is a race where we could get here without a
                 * host route, so nothing to insert. That will be fixed when
                 * the device is brought up.
                 */
                if (ifp->rt && !rcu_access_pointer(ifp->rt->fib6_node)) {
                        ip6_ins_rt(net, ifp->rt);
                } else if (!ifp->rt && (ifp->idev->dev->flags & IFF_UP)) {
                        pr_warn("BUG: Address %pI6c on device %s is missing its host route.\n",
                                &ifp->addr, ifp->idev->dev->name);
                }

                if (ifp->idev->cnf.forwarding)
                        addrconf_join_anycast(ifp);
                if (!ipv6_addr_any(&ifp->peer_addr))
                        addrconf_prefix_route(&ifp->peer_addr, 128,
                                              ifp->rt_priority, ifp->idev->dev,
                                              0, 0, GFP_ATOMIC);
                break;
        case RTM_DELADDR:
                if (ifp->idev->cnf.forwarding)
                        addrconf_leave_anycast(ifp);
                addrconf_leave_solict(ifp->idev, &ifp->addr);
                if (!ipv6_addr_any(&ifp->peer_addr)) {
                        struct fib6_info *rt;

                        rt = addrconf_get_prefix_route(&ifp->peer_addr, 128,
                                                       ifp->idev->dev, 0, 0,
                                                       false);
                        if (rt)
                                ip6_del_rt(net, rt, false);
                }
                if (ifp->rt) {
                        ip6_del_rt(net, ifp->rt, false);
                        ifp->rt = NULL;
                }
                rt_genid_bump_ipv6(net);
                break;
        }
        atomic_inc(&net->ipv6.dev_addr_genid);
}

static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
{
        if (likely(ifp->idev->dead == 0))
                __ipv6_ifa_notify(event, ifp);
}

#ifdef CONFIG_SYSCTL

static int addrconf_sysctl_forward(const struct ctl_table *ctl, int write,
                void *buffer, size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        loff_t pos = *ppos;
        struct ctl_table lctl;
        int ret;

        /*
         * ctl->data points to idev->cnf.forwarding, we should
         * not modify it until we get the rtnl lock.
         */
        lctl = *ctl;
        lctl.data = &val;

        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);

        if (write)
                ret = addrconf_fixup_forwarding(ctl, valp, val);
        if (ret)
                *ppos = pos;
        return ret;
}

static int addrconf_sysctl_mtu(const struct ctl_table *ctl, int write,
                void *buffer, size_t *lenp, loff_t *ppos)
{
        struct inet6_dev *idev = ctl->extra1;
        int min_mtu = IPV6_MIN_MTU;
        struct ctl_table lctl;

        lctl = *ctl;
        lctl.extra1 = &min_mtu;
        lctl.extra2 = idev ? &idev->dev->mtu : NULL;

        return proc_dointvec_minmax(&lctl, write, buffer, lenp, ppos);
}

static void dev_disable_change(struct inet6_dev *idev)
{
        struct netdev_notifier_info info;

        if (!idev || !idev->dev)
                return;

        netdev_notifier_info_init(&info, idev->dev);
        if (idev->cnf.disable_ipv6)
                addrconf_notify(NULL, NETDEV_DOWN, &info);
        else
                addrconf_notify(NULL, NETDEV_UP, &info);
}

static void addrconf_disable_change(struct net *net, __s32 newf)
{
        struct net_device *dev;
        struct inet6_dev *idev;

        for_each_netdev(net, dev) {
                idev = __in6_dev_get_rtnl_net(dev);
                if (idev) {
                        int changed = (!idev->cnf.disable_ipv6) ^ (!newf);

                        WRITE_ONCE(idev->cnf.disable_ipv6, newf);
                        if (changed)
                                dev_disable_change(idev);
                }
        }
}

static int addrconf_disable_ipv6(const struct ctl_table *table, int *p, int newf)
{
        struct net *net = (struct net *)table->extra2;
        int old;

        if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
                WRITE_ONCE(*p, newf);
                return 0;
        }

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        old = *p;
        WRITE_ONCE(*p, newf);

        if (p == &net->ipv6.devconf_all->disable_ipv6) {
                WRITE_ONCE(net->ipv6.devconf_dflt->disable_ipv6, newf);
                addrconf_disable_change(net, newf);
        } else if ((!newf) ^ (!old)) {
                dev_disable_change((struct inet6_dev *)table->extra1);
        }

        rtnl_net_unlock(net);
        return 0;
}

static int addrconf_sysctl_disable(const struct ctl_table *ctl, int write,
                void *buffer, size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        loff_t pos = *ppos;
        struct ctl_table lctl;
        int ret;

        /*
         * ctl->data points to idev->cnf.disable_ipv6, we should
         * not modify it until we get the rtnl lock.
         */
        lctl = *ctl;
        lctl.data = &val;

        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);

        if (write)
                ret = addrconf_disable_ipv6(ctl, valp, val);
        if (ret)
                *ppos = pos;
        return ret;
}

static int addrconf_sysctl_proxy_ndp(const struct ctl_table *ctl, int write,
                void *buffer, size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int ret;
        int old, new;

        old = *valp;
        ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
        new = *valp;

        if (write && old != new) {
                struct net *net = ctl->extra2;

                if (!rtnl_net_trylock(net))
                        return restart_syscall();

                if (valp == &net->ipv6.devconf_dflt->proxy_ndp) {
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_PROXY_NEIGH,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);
                } else if (valp == &net->ipv6.devconf_all->proxy_ndp) {
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_PROXY_NEIGH,
                                                     NETCONFA_IFINDEX_ALL,
                                                     net->ipv6.devconf_all);
                } else {
                        struct inet6_dev *idev = ctl->extra1;

                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_PROXY_NEIGH,
                                                     idev->dev->ifindex,
                                                     &idev->cnf);
                }
                rtnl_net_unlock(net);
        }

        return ret;
}

static int addrconf_sysctl_addr_gen_mode(const struct ctl_table *ctl, int write,
                                         void *buffer, size_t *lenp,
                                         loff_t *ppos)
{
        int ret = 0;
        u32 new_val;
        struct inet6_dev *idev = (struct inet6_dev *)ctl->extra1;
        struct net *net = (struct net *)ctl->extra2;
        struct ctl_table tmp = {
                .data = &new_val,
                .maxlen = sizeof(new_val),
                .mode = ctl->mode,
        };

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        new_val = *((u32 *)ctl->data);

        ret = proc_douintvec(&tmp, write, buffer, lenp, ppos);
        if (ret != 0)
                goto out;

        if (write) {
                if (check_addr_gen_mode(new_val) < 0) {
                        ret = -EINVAL;
                        goto out;
                }

                if (idev) {
                        if (check_stable_privacy(idev, net, new_val) < 0) {
                                ret = -EINVAL;
                                goto out;
                        }

                        if (idev->cnf.addr_gen_mode != new_val) {
                                WRITE_ONCE(idev->cnf.addr_gen_mode, new_val);
                                netdev_lock_ops(idev->dev);
                                addrconf_init_auto_addrs(idev->dev);
                                netdev_unlock_ops(idev->dev);
                        }
                } else if (&net->ipv6.devconf_all->addr_gen_mode == ctl->data) {
                        struct net_device *dev;

                        WRITE_ONCE(net->ipv6.devconf_dflt->addr_gen_mode, new_val);
                        for_each_netdev(net, dev) {
                                idev = __in6_dev_get_rtnl_net(dev);
                                if (idev &&
                                    idev->cnf.addr_gen_mode != new_val) {
                                        WRITE_ONCE(idev->cnf.addr_gen_mode,
                                                  new_val);
                                        netdev_lock_ops(idev->dev);
                                        addrconf_init_auto_addrs(idev->dev);
                                        netdev_unlock_ops(idev->dev);
                                }
                        }
                }

                WRITE_ONCE(*((u32 *)ctl->data), new_val);
        }

out:
        rtnl_net_unlock(net);

        return ret;
}

static int addrconf_sysctl_stable_secret(const struct ctl_table *ctl, int write,
                                         void *buffer, size_t *lenp,
                                         loff_t *ppos)
{
        int err;
        struct in6_addr addr;
        char str[IPV6_MAX_STRLEN];
        struct ctl_table lctl = *ctl;
        struct net *net = ctl->extra2;
        struct ipv6_stable_secret *secret = ctl->data;

        if (&net->ipv6.devconf_all->stable_secret == ctl->data)
                return -EIO;

        lctl.maxlen = IPV6_MAX_STRLEN;
        lctl.data = str;

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        if (!write && !secret->initialized) {
                err = -EIO;
                goto out;
        }

        err = snprintf(str, sizeof(str), "%pI6", &secret->secret);
        if (err >= sizeof(str)) {
                err = -EIO;
                goto out;
        }

        err = proc_dostring(&lctl, write, buffer, lenp, ppos);
        if (err || !write)
                goto out;

        if (in6_pton(str, -1, addr.in6_u.u6_addr8, -1, NULL) != 1) {
                err = -EIO;
                goto out;
        }

        secret->initialized = true;
        secret->secret = addr;

        if (&net->ipv6.devconf_dflt->stable_secret == ctl->data) {
                struct net_device *dev;

                for_each_netdev(net, dev) {
                        struct inet6_dev *idev = __in6_dev_get_rtnl_net(dev);

                        if (idev) {
                                WRITE_ONCE(idev->cnf.addr_gen_mode,
                                           IN6_ADDR_GEN_MODE_STABLE_PRIVACY);
                        }
                }
        } else {
                struct inet6_dev *idev = ctl->extra1;

                WRITE_ONCE(idev->cnf.addr_gen_mode,
                           IN6_ADDR_GEN_MODE_STABLE_PRIVACY);
        }

out:
        rtnl_net_unlock(net);

        return err;
}

static
int addrconf_sysctl_ignore_routes_with_linkdown(const struct ctl_table *ctl,
                                                int write, void *buffer,
                                                size_t *lenp,
                                                loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        loff_t pos = *ppos;
        struct ctl_table lctl;
        int ret;

        /* ctl->data points to idev->cnf.ignore_routes_when_linkdown
         * we should not modify it until we get the rtnl lock.
         */
        lctl = *ctl;
        lctl.data = &val;

        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);

        if (write)
                ret = addrconf_fixup_linkdown(ctl, valp, val);
        if (ret)
                *ppos = pos;
        return ret;
}

static
void addrconf_set_nopolicy(struct rt6_info *rt, int action)
{
        if (rt) {
                if (action)
                        rt->dst.flags |= DST_NOPOLICY;
                else
                        rt->dst.flags &= ~DST_NOPOLICY;
        }
}

static
void addrconf_disable_policy_idev(struct inet6_dev *idev, int val)
{
        struct inet6_ifaddr *ifa;

        read_lock_bh(&idev->lock);
        list_for_each_entry(ifa, &idev->addr_list, if_list) {
                spin_lock(&ifa->lock);
                if (ifa->rt) {
                        /* host routes only use builtin fib6_nh */
                        struct fib6_nh *nh = ifa->rt->fib6_nh;
                        int cpu;

                        rcu_read_lock();
                        ifa->rt->dst_nopolicy = val ? true : false;
                        if (nh->rt6i_pcpu) {
                                for_each_possible_cpu(cpu) {
                                        struct rt6_info **rtp;

                                        rtp = per_cpu_ptr(nh->rt6i_pcpu, cpu);
                                        addrconf_set_nopolicy(*rtp, val);
                                }
                        }
                        rcu_read_unlock();
                }
                spin_unlock(&ifa->lock);
        }
        read_unlock_bh(&idev->lock);
}

static
int addrconf_disable_policy(const struct ctl_table *ctl, int *valp, int val)
{
        struct net *net = (struct net *)ctl->extra2;
        struct inet6_dev *idev;

        if (valp == &net->ipv6.devconf_dflt->disable_policy) {
                WRITE_ONCE(*valp, val);
                return 0;
        }

        if (!rtnl_net_trylock(net))
                return restart_syscall();

        WRITE_ONCE(*valp, val);

        if (valp == &net->ipv6.devconf_all->disable_policy)  {
                struct net_device *dev;

                for_each_netdev(net, dev) {
                        idev = __in6_dev_get_rtnl_net(dev);
                        if (idev)
                                addrconf_disable_policy_idev(idev, val);
                }
        } else {
                idev = (struct inet6_dev *)ctl->extra1;
                addrconf_disable_policy_idev(idev, val);
        }

        rtnl_net_unlock(net);
        return 0;
}

static int addrconf_sysctl_disable_policy(const struct ctl_table *ctl, int write,
                                   void *buffer, size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        loff_t pos = *ppos;
        struct ctl_table lctl;
        int ret;

        lctl = *ctl;
        lctl.data = &val;
        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);

        if (write && (*valp != val))
                ret = addrconf_disable_policy(ctl, valp, val);

        if (ret)
                *ppos = pos;

        return ret;
}

static void addrconf_force_forward_change(struct net *net, __s32 newf)
{
        struct net_device *dev;
        struct inet6_dev *idev;

        for_each_netdev(net, dev) {
                idev = __in6_dev_get_rtnl_net(dev);
                if (idev) {
                        int changed = (!idev->cnf.force_forwarding) ^ (!newf);

                        WRITE_ONCE(idev->cnf.force_forwarding, newf);
                        if (changed)
                                inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,
                                                             NETCONFA_FORCE_FORWARDING,
                                                             dev->ifindex, &idev->cnf);
                }
        }
}

static int addrconf_sysctl_force_forwarding(const struct ctl_table *ctl, int write,
                                            void *buffer, size_t *lenp, loff_t *ppos)
{
        struct inet6_dev *idev = ctl->extra1;
        struct ctl_table tmp_ctl = *ctl;
        struct net *net = ctl->extra2;
        int *valp = ctl->data;
        int new_val = *valp;
        int old_val = *valp;
        loff_t pos = *ppos;
        int ret;

        tmp_ctl.extra1 = SYSCTL_ZERO;
        tmp_ctl.extra2 = SYSCTL_ONE;
        tmp_ctl.data = &new_val;

        ret = proc_douintvec_minmax(&tmp_ctl, write, buffer, lenp, ppos);

        if (write && old_val != new_val) {
                if (!rtnl_net_trylock(net))
                        return restart_syscall();

                WRITE_ONCE(*valp, new_val);

                if (valp == &net->ipv6.devconf_dflt->force_forwarding) {
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORCE_FORWARDING,
                                                     NETCONFA_IFINDEX_DEFAULT,
                                                     net->ipv6.devconf_dflt);
                } else if (valp == &net->ipv6.devconf_all->force_forwarding) {
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORCE_FORWARDING,
                                                     NETCONFA_IFINDEX_ALL,
                                                     net->ipv6.devconf_all);

                        addrconf_force_forward_change(net, new_val);
                } else {
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_FORCE_FORWARDING,
                                                     idev->dev->ifindex,
                                                     &idev->cnf);
                }
                rtnl_net_unlock(net);
        }

        if (ret)
                *ppos = pos;
        return ret;
}

static int minus_one = -1;
static const int two_five_five = 255;
static u32 ioam6_if_id_max = U16_MAX;

static const struct ctl_table addrconf_sysctl[] = {
        {
                .procname       = "forwarding",
                .data           = &ipv6_devconf.forwarding,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_forward,
        },
        {
                .procname       = "hop_limit",
                .data           = &ipv6_devconf.hop_limit,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = (void *)SYSCTL_ONE,
                .extra2         = (void *)&two_five_five,
        },
        {
                .procname       = "mtu",
                .data           = &ipv6_devconf.mtu6,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_mtu,
        },
        {
                .procname       = "accept_ra",
                .data           = &ipv6_devconf.accept_ra,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_redirects",
                .data           = &ipv6_devconf.accept_redirects,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "autoconf",
                .data           = &ipv6_devconf.autoconf,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "dad_transmits",
                .data           = &ipv6_devconf.dad_transmits,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "router_solicitations",
                .data           = &ipv6_devconf.rtr_solicits,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &minus_one,
        },
        {
                .procname       = "router_solicitation_interval",
                .data           = &ipv6_devconf.rtr_solicit_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "router_solicitation_max_interval",
                .data           = &ipv6_devconf.rtr_solicit_max_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "router_solicitation_delay",
                .data           = &ipv6_devconf.rtr_solicit_delay,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "force_mld_version",
                .data           = &ipv6_devconf.force_mld_version,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "mldv1_unsolicited_report_interval",
                .data           =
                        &ipv6_devconf.mldv1_unsolicited_report_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_ms_jiffies,
        },
        {
                .procname       = "mldv2_unsolicited_report_interval",
                .data           =
                        &ipv6_devconf.mldv2_unsolicited_report_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_ms_jiffies,
        },
        {
                .procname       = "use_tempaddr",
                .data           = &ipv6_devconf.use_tempaddr,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "temp_valid_lft",
                .data           = &ipv6_devconf.temp_valid_lft,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "temp_prefered_lft",
                .data           = &ipv6_devconf.temp_prefered_lft,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "regen_min_advance",
                .data           = &ipv6_devconf.regen_min_advance,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "regen_max_retry",
                .data           = &ipv6_devconf.regen_max_retry,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "max_desync_factor",
                .data           = &ipv6_devconf.max_desync_factor,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "max_addresses",
                .data           = &ipv6_devconf.max_addresses,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_ra_defrtr",
                .data           = &ipv6_devconf.accept_ra_defrtr,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ra_defrtr_metric",
                .data           = &ipv6_devconf.ra_defrtr_metric,
                .maxlen         = sizeof(u32),
                .mode           = 0644,
                .proc_handler   = proc_douintvec_minmax,
                .extra1         = (void *)SYSCTL_ONE,
        },
        {
                .procname       = "accept_ra_min_hop_limit",
                .data           = &ipv6_devconf.accept_ra_min_hop_limit,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_ra_min_lft",
                .data           = &ipv6_devconf.accept_ra_min_lft,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_ra_pinfo",
                .data           = &ipv6_devconf.accept_ra_pinfo,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ra_honor_pio_life",
                .data           = &ipv6_devconf.ra_honor_pio_life,
                .maxlen         = sizeof(u8),
                .mode           = 0644,
                .proc_handler   = proc_dou8vec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
        {
                .procname       = "ra_honor_pio_pflag",
                .data           = &ipv6_devconf.ra_honor_pio_pflag,
                .maxlen         = sizeof(u8),
                .mode           = 0644,
                .proc_handler   = proc_dou8vec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
#ifdef CONFIG_IPV6_ROUTER_PREF
        {
                .procname       = "accept_ra_rtr_pref",
                .data           = &ipv6_devconf.accept_ra_rtr_pref,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "router_probe_interval",
                .data           = &ipv6_devconf.rtr_probe_interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
#ifdef CONFIG_IPV6_ROUTE_INFO
        {
                .procname       = "accept_ra_rt_info_min_plen",
                .data           = &ipv6_devconf.accept_ra_rt_info_min_plen,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_ra_rt_info_max_plen",
                .data           = &ipv6_devconf.accept_ra_rt_info_max_plen,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#endif
        {
                .procname       = "proxy_ndp",
                .data           = &ipv6_devconf.proxy_ndp,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_proxy_ndp,
        },
        {
                .procname       = "accept_source_route",
                .data           = &ipv6_devconf.accept_source_route,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        {
                .procname       = "optimistic_dad",
                .data           = &ipv6_devconf.optimistic_dad,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "use_optimistic",
                .data           = &ipv6_devconf.use_optimistic,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_IPV6_MROUTE
        {
                .procname       = "mc_forwarding",
                .data           = &ipv6_devconf.mc_forwarding,
                .maxlen         = sizeof(int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "disable_ipv6",
                .data           = &ipv6_devconf.disable_ipv6,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_disable,
        },
        {
                .procname       = "accept_dad",
                .data           = &ipv6_devconf.accept_dad,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "force_tllao",
                .data           = &ipv6_devconf.force_tllao,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec
        },
        {
                .procname       = "ndisc_notify",
                .data           = &ipv6_devconf.ndisc_notify,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec
        },
        {
                .procname       = "suppress_frag_ndisc",
                .data           = &ipv6_devconf.suppress_frag_ndisc,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec
        },
        {
                .procname       = "accept_ra_from_local",
                .data           = &ipv6_devconf.accept_ra_from_local,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "accept_ra_mtu",
                .data           = &ipv6_devconf.accept_ra_mtu,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "stable_secret",
                .data           = &ipv6_devconf.stable_secret,
                .maxlen         = IPV6_MAX_STRLEN,
                .mode           = 0600,
                .proc_handler   = addrconf_sysctl_stable_secret,
        },
        {
                .procname       = "use_oif_addrs_only",
                .data           = &ipv6_devconf.use_oif_addrs_only,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "ignore_routes_with_linkdown",
                .data           = &ipv6_devconf.ignore_routes_with_linkdown,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_ignore_routes_with_linkdown,
        },
        {
                .procname       = "drop_unicast_in_l2_multicast",
                .data           = &ipv6_devconf.drop_unicast_in_l2_multicast,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "drop_unsolicited_na",
                .data           = &ipv6_devconf.drop_unsolicited_na,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "keep_addr_on_down",
                .data           = &ipv6_devconf.keep_addr_on_down,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,

        },
        {
                .procname       = "seg6_enabled",
                .data           = &ipv6_devconf.seg6_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_IPV6_SEG6_HMAC
        {
                .procname       = "seg6_require_hmac",
                .data           = &ipv6_devconf.seg6_require_hmac,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "enhanced_dad",
                .data           = &ipv6_devconf.enhanced_dad,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "addr_gen_mode",
                .data           = &ipv6_devconf.addr_gen_mode,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_addr_gen_mode,
        },
        {
                .procname       = "disable_policy",
                .data           = &ipv6_devconf.disable_policy,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_disable_policy,
        },
        {
                .procname       = "ndisc_tclass",
                .data           = &ipv6_devconf.ndisc_tclass,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = (void *)SYSCTL_ZERO,
                .extra2         = (void *)&two_five_five,
        },
        {
                .procname       = "rpl_seg_enabled",
                .data           = &ipv6_devconf.rpl_seg_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
        {
                .procname       = "ioam6_enabled",
                .data           = &ipv6_devconf.ioam6_enabled,
                .maxlen         = sizeof(u8),
                .mode           = 0644,
                .proc_handler   = proc_dou8vec_minmax,
                .extra1         = (void *)SYSCTL_ZERO,
                .extra2         = (void *)SYSCTL_ONE,
        },
        {
                .procname       = "ioam6_id",
                .data           = &ipv6_devconf.ioam6_id,
                .maxlen         = sizeof(u32),
                .mode           = 0644,
                .proc_handler   = proc_douintvec_minmax,
                .extra1         = (void *)SYSCTL_ZERO,
                .extra2         = (void *)&ioam6_if_id_max,
        },
        {
                .procname       = "ioam6_id_wide",
                .data           = &ipv6_devconf.ioam6_id_wide,
                .maxlen         = sizeof(u32),
                .mode           = 0644,
                .proc_handler   = proc_douintvec,
        },
        {
                .procname       = "ndisc_evict_nocarrier",
                .data           = &ipv6_devconf.ndisc_evict_nocarrier,
                .maxlen         = sizeof(u8),
                .mode           = 0644,
                .proc_handler   = proc_dou8vec_minmax,
                .extra1         = (void *)SYSCTL_ZERO,
                .extra2         = (void *)SYSCTL_ONE,
        },
        {
                .procname       = "accept_untracked_na",
                .data           = &ipv6_devconf.accept_untracked_na,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_TWO,
        },
        {
                .procname       = "force_forwarding",
                .data           = &ipv6_devconf.force_forwarding,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = addrconf_sysctl_force_forwarding,
        },
};

static int __addrconf_sysctl_register(struct net *net, char *dev_name,
                struct inet6_dev *idev, struct ipv6_devconf *p)
{
        size_t table_size = ARRAY_SIZE(addrconf_sysctl);
        int i, ifindex;
        struct ctl_table *table;
        char path[sizeof("net/ipv6/conf/") + IFNAMSIZ];

        table = kmemdup(addrconf_sysctl, sizeof(addrconf_sysctl), GFP_KERNEL_ACCOUNT);
        if (!table)
                goto out;

        for (i = 0; i < table_size; i++) {
                table[i].data += (char *)p - (char *)&ipv6_devconf;
                /* If one of these is already set, then it is not safe to
                 * overwrite either of them: this makes proc_dointvec_minmax
                 * usable.
                 */
                if (!table[i].extra1 && !table[i].extra2) {
                        table[i].extra1 = idev; /* embedded; no ref */
                        table[i].extra2 = net;
                }
        }

        snprintf(path, sizeof(path), "net/ipv6/conf/%s", dev_name);

        p->sysctl_header = register_net_sysctl_sz(net, path, table,
                                                  table_size);
        if (!p->sysctl_header)
                goto free;

        if (!strcmp(dev_name, "all"))
                ifindex = NETCONFA_IFINDEX_ALL;
        else if (!strcmp(dev_name, "default"))
                ifindex = NETCONFA_IFINDEX_DEFAULT;
        else
                ifindex = idev->dev->ifindex;
        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_ALL,
                                     ifindex, p);
        return 0;

free:
        kfree(table);
out:
        return -ENOBUFS;
}

static void __addrconf_sysctl_unregister(struct net *net,
                                         struct ipv6_devconf *p, int ifindex)
{
        const struct ctl_table *table;

        if (!p->sysctl_header)
                return;

        table = p->sysctl_header->ctl_table_arg;
        unregister_net_sysctl_table(p->sysctl_header);
        p->sysctl_header = NULL;
        kfree(table);

        inet6_netconf_notify_devconf(net, RTM_DELNETCONF, 0, ifindex, NULL);
}

static int addrconf_sysctl_register(struct inet6_dev *idev)
{
        int err;

        if (!sysctl_dev_name_is_allowed(idev->dev->name))
                return -EINVAL;

        err = neigh_sysctl_register(idev->dev, idev->nd_parms,
                                    &ndisc_ifinfo_sysctl_change);
        if (err)
                return err;
        err = __addrconf_sysctl_register(dev_net(idev->dev), idev->dev->name,
                                         idev, &idev->cnf);
        if (err)
                neigh_sysctl_unregister(idev->nd_parms);

        return err;
}

static void addrconf_sysctl_unregister(struct inet6_dev *idev)
{
        __addrconf_sysctl_unregister(dev_net(idev->dev), &idev->cnf,
                                     idev->dev->ifindex);
        neigh_sysctl_unregister(idev->nd_parms);
}


#endif

static int __net_init addrconf_init_net(struct net *net)
{
        int err = -ENOMEM;
        struct ipv6_devconf *all, *dflt;

        spin_lock_init(&net->ipv6.addrconf_hash_lock);
        INIT_DEFERRABLE_WORK(&net->ipv6.addr_chk_work, addrconf_verify_work);
        net->ipv6.inet6_addr_lst = kzalloc_objs(struct hlist_head,
                                                IN6_ADDR_HSIZE);
        if (!net->ipv6.inet6_addr_lst)
                goto err_alloc_addr;

        all = kmemdup(&ipv6_devconf, sizeof(ipv6_devconf), GFP_KERNEL);
        if (!all)
                goto err_alloc_all;

        dflt = kmemdup(&ipv6_devconf_dflt, sizeof(ipv6_devconf_dflt), GFP_KERNEL);
        if (!dflt)
                goto err_alloc_dflt;

        if (!net_eq(net, &init_net)) {
                switch (net_inherit_devconf()) {
                case 1:  /* copy from init_net */
                        memcpy(all, init_net.ipv6.devconf_all,
                               sizeof(ipv6_devconf));
                        memcpy(dflt, init_net.ipv6.devconf_dflt,
                               sizeof(ipv6_devconf_dflt));
                        break;
                case 3: /* copy from the current netns */
                        memcpy(all, current->nsproxy->net_ns->ipv6.devconf_all,
                               sizeof(ipv6_devconf));
                        memcpy(dflt,
                               current->nsproxy->net_ns->ipv6.devconf_dflt,
                               sizeof(ipv6_devconf_dflt));
                        break;
                case 0:
                case 2:
                        /* use compiled values */
                        break;
                }
        }

        /* these will be inherited by all namespaces */
        dflt->autoconf = ipv6_defaults.autoconf;
        dflt->disable_ipv6 = ipv6_defaults.disable_ipv6;

        dflt->stable_secret.initialized = false;
        all->stable_secret.initialized = false;

        net->ipv6.devconf_all = all;
        net->ipv6.devconf_dflt = dflt;

#ifdef CONFIG_SYSCTL
        err = __addrconf_sysctl_register(net, "all", NULL, all);
        if (err < 0)
                goto err_reg_all;

        err = __addrconf_sysctl_register(net, "default", NULL, dflt);
        if (err < 0)
                goto err_reg_dflt;
#endif
        return 0;

#ifdef CONFIG_SYSCTL
err_reg_dflt:
        __addrconf_sysctl_unregister(net, all, NETCONFA_IFINDEX_ALL);
err_reg_all:
        kfree(dflt);
        net->ipv6.devconf_dflt = NULL;
#endif
err_alloc_dflt:
        kfree(all);
        net->ipv6.devconf_all = NULL;
err_alloc_all:
        kfree(net->ipv6.inet6_addr_lst);
err_alloc_addr:
        return err;
}

static void __net_exit addrconf_exit_net(struct net *net)
{
        int i;

#ifdef CONFIG_SYSCTL
        __addrconf_sysctl_unregister(net, net->ipv6.devconf_dflt,
                                     NETCONFA_IFINDEX_DEFAULT);
        __addrconf_sysctl_unregister(net, net->ipv6.devconf_all,
                                     NETCONFA_IFINDEX_ALL);
#endif
        kfree(net->ipv6.devconf_dflt);
        net->ipv6.devconf_dflt = NULL;
        kfree(net->ipv6.devconf_all);
        net->ipv6.devconf_all = NULL;

        cancel_delayed_work_sync(&net->ipv6.addr_chk_work);
        /*
         *      Check hash table, then free it.
         */
        for (i = 0; i < IN6_ADDR_HSIZE; i++)
                WARN_ON_ONCE(!hlist_empty(&net->ipv6.inet6_addr_lst[i]));

        kfree(net->ipv6.inet6_addr_lst);
        net->ipv6.inet6_addr_lst = NULL;
}

static struct pernet_operations addrconf_ops = {
        .init = addrconf_init_net,
        .exit = addrconf_exit_net,
};

static struct rtnl_af_ops inet6_ops __read_mostly = {
        .family           = AF_INET6,
        .fill_link_af     = inet6_fill_link_af,
        .get_link_af_size = inet6_get_link_af_size,
        .validate_link_af = inet6_validate_link_af,
        .set_link_af      = inet6_set_link_af,
};

static const struct rtnl_msg_handler addrconf_rtnl_msg_handlers[] __initconst_or_module = {
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETLINK,
         .dumpit = inet6_dump_ifinfo, .flags = RTNL_FLAG_DUMP_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_NEWADDR,
         .doit = inet6_rtm_newaddr, .flags = RTNL_FLAG_DOIT_PERNET},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_DELADDR,
         .doit = inet6_rtm_deladdr, .flags = RTNL_FLAG_DOIT_PERNET},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETADDR,
         .doit = inet6_rtm_getaddr, .dumpit = inet6_dump_ifaddr,
         .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETMULTICAST,
         .dumpit = inet6_dump_ifmcaddr,
         .flags = RTNL_FLAG_DUMP_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETANYCAST,
         .dumpit = inet6_dump_ifacaddr,
         .flags = RTNL_FLAG_DUMP_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_INET6, .msgtype = RTM_GETNETCONF,
         .doit = inet6_netconf_get_devconf, .dumpit = inet6_netconf_dump_devconf,
         .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
};

/*
 *      Init / cleanup code
 */

int __init addrconf_init(void)
{
        struct inet6_dev *idev;
        int err;

        err = ipv6_addr_label_init();
        if (err < 0) {
                pr_crit("%s: cannot initialize default policy table: %d\n",
                        __func__, err);
                goto out;
        }

        err = register_pernet_subsys(&addrconf_ops);
        if (err < 0)
                goto out_addrlabel;

        /* All works using addrconf_wq need to lock rtnl. */
        addrconf_wq = create_singlethread_workqueue("ipv6_addrconf");
        if (!addrconf_wq) {
                err = -ENOMEM;
                goto out_nowq;
        }

        rtnl_net_lock(&init_net);
        idev = ipv6_add_dev(blackhole_netdev);
        rtnl_net_unlock(&init_net);
        if (IS_ERR(idev)) {
                err = PTR_ERR(idev);
                goto errlo;
        }

        ip6_route_init_special_entries();

        register_netdevice_notifier(&ipv6_dev_notf);

        addrconf_verify(&init_net);

        err = rtnl_af_register(&inet6_ops);
        if (err)
                goto erraf;

        err = rtnl_register_many(addrconf_rtnl_msg_handlers);
        if (err)
                goto errout;

        err = ipv6_addr_label_rtnl_register();
        if (err < 0)
                goto errout;

        return 0;
errout:
        rtnl_unregister_all(PF_INET6);
        rtnl_af_unregister(&inet6_ops);
erraf:
        unregister_netdevice_notifier(&ipv6_dev_notf);
errlo:
        destroy_workqueue(addrconf_wq);
out_nowq:
        unregister_pernet_subsys(&addrconf_ops);
out_addrlabel:
        ipv6_addr_label_cleanup();
out:
        return err;
}

void addrconf_cleanup(void)
{
        struct net_device *dev;

        unregister_netdevice_notifier(&ipv6_dev_notf);
        unregister_pernet_subsys(&addrconf_ops);
        ipv6_addr_label_cleanup();

        rtnl_af_unregister(&inet6_ops);

        rtnl_net_lock(&init_net);

        /* clean dev list */
        for_each_netdev(&init_net, dev) {
                if (!__in6_dev_get_rtnl_net(dev))
                        continue;
                addrconf_ifdown(dev, true);
        }
        addrconf_ifdown(init_net.loopback_dev, true);

        rtnl_net_unlock(&init_net);

        destroy_workqueue(addrconf_wq);
}