root/net/ipv6/ipv6_sockglue.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      IPv6 BSD socket options interface
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *
 *      Based on linux/net/ipv4/ip_sockglue.c
 *
 *      FIXME: Make the setsockopt code POSIX compliant: That is
 *
 *      o       Truncate getsockopt returns
 *      o       Return an optlen of the truncated length if need be
 *
 *      Changes:
 *      David L Stevens <dlstevens@us.ibm.com>:
 *              - added multicast source filtering API for MLDv2
 */

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/mroute6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/netfilter.h>
#include <linux/slab.h>

#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/inet_common.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/udplite.h>
#include <net/xfrm.h>
#include <net/compat.h>
#include <net/seg6.h>
#include <net/psp.h>

#include <linux/uaccess.h>

struct ip6_ra_chain *ip6_ra_chain;
DEFINE_RWLOCK(ip6_ra_lock);

DEFINE_STATIC_KEY_FALSE(ip6_min_hopcount);

int ip6_ra_control(struct sock *sk, int sel)
{
        struct ip6_ra_chain *ra, *new_ra, **rap;

        /* RA packet may be delivered ONLY to IPPROTO_RAW socket */
        if (sk->sk_type != SOCK_RAW || inet_sk(sk)->inet_num != IPPROTO_RAW)
                return -ENOPROTOOPT;

        new_ra = (sel >= 0) ? kmalloc_obj(*new_ra) : NULL;
        if (sel >= 0 && !new_ra)
                return -ENOMEM;

        write_lock_bh(&ip6_ra_lock);
        for (rap = &ip6_ra_chain; (ra = *rap) != NULL; rap = &ra->next) {
                if (ra->sk == sk) {
                        if (sel >= 0) {
                                write_unlock_bh(&ip6_ra_lock);
                                kfree(new_ra);
                                return -EADDRINUSE;
                        }

                        *rap = ra->next;
                        write_unlock_bh(&ip6_ra_lock);

                        sock_put(sk);
                        kfree(ra);
                        return 0;
                }
        }
        if (!new_ra) {
                write_unlock_bh(&ip6_ra_lock);
                return -ENOBUFS;
        }
        new_ra->sk = sk;
        new_ra->sel = sel;
        new_ra->next = ra;
        *rap = new_ra;
        sock_hold(sk);
        write_unlock_bh(&ip6_ra_lock);
        return 0;
}

struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
                                           struct ipv6_txoptions *opt)
{
        if (inet_test_bit(IS_ICSK, sk)) {
                if (opt &&
                    !((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) &&
                    inet_sk(sk)->inet_daddr != LOOPBACK4_IPV6) {
                        struct inet_connection_sock *icsk = inet_csk(sk);

                        icsk->icsk_ext_hdr_len =
                                psp_sk_overhead(sk) +
                                opt->opt_flen + opt->opt_nflen;
                        icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
                }
        }
        opt = unrcu_pointer(xchg(&inet6_sk(sk)->opt, RCU_INITIALIZER(opt)));
        sk_dst_reset(sk);

        return opt;
}

static int copy_group_source_from_sockptr(struct group_source_req *greqs,
                sockptr_t optval, int optlen)
{
        if (in_compat_syscall()) {
                struct compat_group_source_req gr32;

                if (optlen < sizeof(gr32))
                        return -EINVAL;
                if (copy_from_sockptr(&gr32, optval, sizeof(gr32)))
                        return -EFAULT;
                greqs->gsr_interface = gr32.gsr_interface;
                greqs->gsr_group = gr32.gsr_group;
                greqs->gsr_source = gr32.gsr_source;
        } else {
                if (optlen < sizeof(*greqs))
                        return -EINVAL;
                if (copy_from_sockptr(greqs, optval, sizeof(*greqs)))
                        return -EFAULT;
        }

        return 0;
}

static int do_ipv6_mcast_group_source(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct group_source_req greqs;
        int omode, add;
        int ret;

        ret = copy_group_source_from_sockptr(&greqs, optval, optlen);
        if (ret)
                return ret;

        if (greqs.gsr_group.ss_family != AF_INET6 ||
            greqs.gsr_source.ss_family != AF_INET6)
                return -EADDRNOTAVAIL;

        if (optname == MCAST_BLOCK_SOURCE) {
                omode = MCAST_EXCLUDE;
                add = 1;
        } else if (optname == MCAST_UNBLOCK_SOURCE) {
                omode = MCAST_EXCLUDE;
                add = 0;
        } else if (optname == MCAST_JOIN_SOURCE_GROUP) {
                struct sockaddr_in6 *psin6;
                int retv;

                psin6 = (struct sockaddr_in6 *)&greqs.gsr_group;
                retv = ipv6_sock_mc_join_ssm(sk, greqs.gsr_interface,
                                             &psin6->sin6_addr,
                                             MCAST_INCLUDE);
                /* prior join w/ different source is ok */
                if (retv && retv != -EADDRINUSE)
                        return retv;
                omode = MCAST_INCLUDE;
                add = 1;
        } else /* MCAST_LEAVE_SOURCE_GROUP */ {
                omode = MCAST_INCLUDE;
                add = 0;
        }
        return ip6_mc_source(add, omode, sk, &greqs);
}

static int ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
                int optlen)
{
        struct group_filter *gsf;
        int ret;

        if (optlen < GROUP_FILTER_SIZE(0))
                return -EINVAL;
        if (optlen > READ_ONCE(sock_net(sk)->core.sysctl_optmem_max))
                return -ENOBUFS;

        gsf = memdup_sockptr(optval, optlen);
        if (IS_ERR(gsf))
                return PTR_ERR(gsf);

        /* numsrc >= (4G-140)/128 overflow in 32 bits */
        ret = -ENOBUFS;
        if (gsf->gf_numsrc >= 0x1ffffffU ||
            gsf->gf_numsrc > sysctl_mld_max_msf)
                goto out_free_gsf;

        ret = -EINVAL;
        if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen)
                goto out_free_gsf;

        ret = ip6_mc_msfilter(sk, gsf, gsf->gf_slist_flex);
out_free_gsf:
        kfree(gsf);
        return ret;
}

static int compat_ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
                int optlen)
{
        const int size0 = offsetof(struct compat_group_filter, gf_slist_flex);
        struct compat_group_filter *gf32;
        void *p;
        int ret;
        int n;

        if (optlen < size0)
                return -EINVAL;
        if (optlen > READ_ONCE(sock_net(sk)->core.sysctl_optmem_max) - 4)
                return -ENOBUFS;

        p = kmalloc(optlen + 4, GFP_KERNEL);
        if (!p)
                return -ENOMEM;

        gf32 = p + 4; /* we want ->gf_group and ->gf_slist_flex aligned */
        ret = -EFAULT;
        if (copy_from_sockptr(gf32, optval, optlen))
                goto out_free_p;

        /* numsrc >= (4G-140)/128 overflow in 32 bits */
        ret = -ENOBUFS;
        n = gf32->gf_numsrc;
        if (n >= 0x1ffffffU || n > sysctl_mld_max_msf)
                goto out_free_p;

        ret = -EINVAL;
        if (offsetof(struct compat_group_filter, gf_slist_flex[n]) > optlen)
                goto out_free_p;

        ret = ip6_mc_msfilter(sk, &(struct group_filter){
                        .gf_interface = gf32->gf_interface,
                        .gf_group = gf32->gf_group,
                        .gf_fmode = gf32->gf_fmode,
                        .gf_numsrc = gf32->gf_numsrc}, gf32->gf_slist_flex);

out_free_p:
        kfree(p);
        return ret;
}

static int ipv6_mcast_join_leave(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct sockaddr_in6 *psin6;
        struct group_req greq;

        if (optlen < sizeof(greq))
                return -EINVAL;
        if (copy_from_sockptr(&greq, optval, sizeof(greq)))
                return -EFAULT;

        if (greq.gr_group.ss_family != AF_INET6)
                return -EADDRNOTAVAIL;
        psin6 = (struct sockaddr_in6 *)&greq.gr_group;
        if (optname == MCAST_JOIN_GROUP)
                return ipv6_sock_mc_join(sk, greq.gr_interface,
                                         &psin6->sin6_addr);
        return ipv6_sock_mc_drop(sk, greq.gr_interface, &psin6->sin6_addr);
}

static int compat_ipv6_mcast_join_leave(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct compat_group_req gr32;
        struct sockaddr_in6 *psin6;

        if (optlen < sizeof(gr32))
                return -EINVAL;
        if (copy_from_sockptr(&gr32, optval, sizeof(gr32)))
                return -EFAULT;

        if (gr32.gr_group.ss_family != AF_INET6)
                return -EADDRNOTAVAIL;
        psin6 = (struct sockaddr_in6 *)&gr32.gr_group;
        if (optname == MCAST_JOIN_GROUP)
                return ipv6_sock_mc_join(sk, gr32.gr_interface,
                                        &psin6->sin6_addr);
        return ipv6_sock_mc_drop(sk, gr32.gr_interface, &psin6->sin6_addr);
}

static int ipv6_set_opt_hdr(struct sock *sk, int optname, sockptr_t optval,
                int optlen)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct ipv6_opt_hdr *new = NULL;
        struct net *net = sock_net(sk);
        struct ipv6_txoptions *opt;
        int err;

        /* hop-by-hop / destination options are privileged option */
        if (optname != IPV6_RTHDR && !sockopt_ns_capable(net->user_ns, CAP_NET_RAW))
                return -EPERM;

        /* remove any sticky options header with a zero option
         * length, per RFC3542.
         */
        if (optlen > 0) {
                if (sockptr_is_null(optval))
                        return -EINVAL;
                if (optlen < sizeof(struct ipv6_opt_hdr) ||
                    optlen & 0x7 ||
                    optlen > 8 * 255)
                        return -EINVAL;

                new = memdup_sockptr(optval, optlen);
                if (IS_ERR(new))
                        return PTR_ERR(new);
                if (unlikely(ipv6_optlen(new) > optlen)) {
                        kfree(new);
                        return -EINVAL;
                }
        }

        opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
        opt = ipv6_renew_options(sk, opt, optname, new);
        kfree(new);
        if (IS_ERR(opt))
                return PTR_ERR(opt);

        /* routing header option needs extra check */
        err = -EINVAL;
        if (optname == IPV6_RTHDR && opt && opt->srcrt) {
                struct ipv6_rt_hdr *rthdr = opt->srcrt;
                switch (rthdr->type) {
#if IS_ENABLED(CONFIG_IPV6_MIP6)
                case IPV6_SRCRT_TYPE_2:
                        if (rthdr->hdrlen != 2 || rthdr->segments_left != 1)
                                goto sticky_done;
                        break;
#endif
                case IPV6_SRCRT_TYPE_4:
                {
                        struct ipv6_sr_hdr *srh =
                                (struct ipv6_sr_hdr *)opt->srcrt;

                        if (!seg6_validate_srh(srh, optlen, false))
                                goto sticky_done;
                        break;
                }
                default:
                        goto sticky_done;
                }
        }

        err = 0;
        opt = ipv6_update_options(sk, opt);
sticky_done:
        if (opt) {
                atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
                txopt_put(opt);
        }
        return err;
}

int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
                       sockptr_t optval, unsigned int optlen)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct net *net = sock_net(sk);
        int retv = -ENOPROTOOPT;
        int val, valbool;

        if (sockptr_is_null(optval))
                val = 0;
        else {
                if (optlen >= sizeof(int)) {
                        if (copy_from_sockptr(&val, optval, sizeof(val)))
                                return -EFAULT;
                } else
                        val = 0;
        }

        valbool = (val != 0);

        if (ip6_mroute_opt(optname))
                return ip6_mroute_setsockopt(sk, optname, optval, optlen);

        /* Handle options that can be set without locking the socket. */
        switch (optname) {
        case IPV6_UNICAST_HOPS:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val > 255 || val < -1)
                        return -EINVAL;
                WRITE_ONCE(np->hop_limit, val);
                return 0;
        case IPV6_MULTICAST_LOOP:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val != valbool)
                        return -EINVAL;
                inet6_assign_bit(MC6_LOOP, sk, valbool);
                return 0;
        case IPV6_MULTICAST_HOPS:
                if (sk->sk_type == SOCK_STREAM)
                        return retv;
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val > 255 || val < -1)
                        return -EINVAL;
                WRITE_ONCE(np->mcast_hops,
                           val == -1 ? IPV6_DEFAULT_MCASTHOPS : val);
                return 0;
        case IPV6_MTU:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val && val < IPV6_MIN_MTU)
                        return -EINVAL;
                WRITE_ONCE(np->frag_size, val);
                return 0;
        case IPV6_MINHOPCOUNT:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val < 0 || val > 255)
                        return -EINVAL;

                if (val)
                        static_branch_enable(&ip6_min_hopcount);

                /* tcp_v6_err() and tcp_v6_rcv() might read min_hopcount
                 * while we are changing it.
                 */
                WRITE_ONCE(np->min_hopcount, val);
                return 0;
        case IPV6_RECVERR_RFC4884:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val < 0 || val > 1)
                        return -EINVAL;
                inet6_assign_bit(RECVERR6_RFC4884, sk, valbool);
                return 0;
        case IPV6_MULTICAST_ALL:
                if (optlen < sizeof(int))
                        return -EINVAL;
                inet6_assign_bit(MC6_ALL, sk, valbool);
                return 0;
        case IPV6_AUTOFLOWLABEL:
                inet6_assign_bit(AUTOFLOWLABEL, sk, valbool);
                inet6_set_bit(AUTOFLOWLABEL_SET, sk);
                return 0;
        case IPV6_DONTFRAG:
                inet6_assign_bit(DONTFRAG, sk, valbool);
                return 0;
        case IPV6_RECVERR:
                if (optlen < sizeof(int))
                        return -EINVAL;
                inet6_assign_bit(RECVERR6, sk, valbool);
                if (!val)
                        skb_errqueue_purge(&sk->sk_error_queue);
                return 0;
        case IPV6_ROUTER_ALERT_ISOLATE:
                if (optlen < sizeof(int))
                        return -EINVAL;
                inet6_assign_bit(RTALERT_ISOLATE, sk, valbool);
                return 0;
        case IPV6_MTU_DISCOVER:
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val < IPV6_PMTUDISC_DONT || val > IPV6_PMTUDISC_OMIT)
                        return -EINVAL;
                WRITE_ONCE(np->pmtudisc, val);
                return 0;
        case IPV6_FLOWINFO_SEND:
                if (optlen < sizeof(int))
                        return -EINVAL;
                inet6_assign_bit(SNDFLOW, sk, valbool);
                return 0;
        case IPV6_ADDR_PREFERENCES:
                if (optlen < sizeof(int))
                        return -EINVAL;
                return ip6_sock_set_addr_preferences(sk, val);
        case IPV6_MULTICAST_IF:
                if (sk->sk_type == SOCK_STREAM)
                        return -ENOPROTOOPT;
                if (optlen < sizeof(int))
                        return -EINVAL;
                if (val) {
                        struct net_device *dev;
                        int bound_dev_if, midx;

                        rcu_read_lock();

                        dev = dev_get_by_index_rcu(net, val);
                        if (!dev) {
                                rcu_read_unlock();
                                return -ENODEV;
                        }
                        midx = l3mdev_master_ifindex_rcu(dev);

                        rcu_read_unlock();

                        bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
                        if (bound_dev_if &&
                            bound_dev_if != val &&
                            (!midx || midx != bound_dev_if))
                                return -EINVAL;
                }
                WRITE_ONCE(np->mcast_oif, val);
                return 0;
        case IPV6_UNICAST_IF:
        {
                struct net_device *dev;
                int ifindex;

                if (optlen != sizeof(int))
                        return -EINVAL;

                ifindex = (__force int)ntohl((__force __be32)val);
                if (!ifindex) {
                        WRITE_ONCE(np->ucast_oif, 0);
                        return 0;
                }

                dev = dev_get_by_index(net, ifindex);
                if (!dev)
                        return -EADDRNOTAVAIL;
                dev_put(dev);

                if (READ_ONCE(sk->sk_bound_dev_if))
                        return -EINVAL;

                WRITE_ONCE(np->ucast_oif, ifindex);
                return 0;
        }
        }

        sockopt_lock_sock(sk);

        /* Another thread has converted the socket into IPv4 with
         * IPV6_ADDRFORM concurrently.
         */
        if (unlikely(sk->sk_family != AF_INET6))
                goto unlock;

        switch (optname) {

        case IPV6_ADDRFORM:
                if (optlen < sizeof(int))
                        goto e_inval;
                if (val == PF_INET) {
                        if (sk->sk_type == SOCK_RAW)
                                break;

                        if (sk->sk_protocol == IPPROTO_UDP ||
                            sk->sk_protocol == IPPROTO_UDPLITE) {
                                struct udp_sock *up = udp_sk(sk);
                                if (up->pending == AF_INET6) {
                                        retv = -EBUSY;
                                        break;
                                }
                        } else if (sk->sk_protocol == IPPROTO_TCP) {
                                if (sk->sk_prot != &tcpv6_prot) {
                                        retv = -EBUSY;
                                        break;
                                }
                        } else {
                                break;
                        }

                        if (sk->sk_state != TCP_ESTABLISHED) {
                                retv = -ENOTCONN;
                                break;
                        }

                        if (ipv6_only_sock(sk) ||
                            !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
                                retv = -EADDRNOTAVAIL;
                                break;
                        }

                        __ipv6_sock_mc_close(sk);
                        __ipv6_sock_ac_close(sk);

                        if (sk->sk_protocol == IPPROTO_TCP) {
                                struct inet_connection_sock *icsk = inet_csk(sk);

                                sock_prot_inuse_add(net, sk->sk_prot, -1);
                                sock_prot_inuse_add(net, &tcp_prot, 1);

                                /* Paired with READ_ONCE(sk->sk_prot) in inet6_stream_ops */
                                WRITE_ONCE(sk->sk_prot, &tcp_prot);
                                /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */
                                WRITE_ONCE(icsk->icsk_af_ops, &ipv4_specific);
                                WRITE_ONCE(sk->sk_socket->ops, &inet_stream_ops);
                                WRITE_ONCE(sk->sk_family, PF_INET);
                                tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
                        } else {
                                struct proto *prot = &udp_prot;

                                if (sk->sk_protocol == IPPROTO_UDPLITE)
                                        prot = &udplite_prot;

                                sock_prot_inuse_add(net, sk->sk_prot, -1);
                                sock_prot_inuse_add(net, prot, 1);

                                /* Paired with READ_ONCE(sk->sk_prot) in inet6_dgram_ops */
                                WRITE_ONCE(sk->sk_prot, prot);
                                WRITE_ONCE(sk->sk_socket->ops, &inet_dgram_ops);
                                WRITE_ONCE(sk->sk_family, PF_INET);
                        }

                        /* Disable all options not to allocate memory anymore,
                         * but there is still a race.  See the lockless path
                         * in udpv6_sendmsg() and ipv6_local_rxpmtu().
                         */
                        np->rxopt.all = 0;

                        inet6_cleanup_sock(sk);

                        module_put(THIS_MODULE);
                        retv = 0;
                        break;
                }
                goto e_inval;

        case IPV6_V6ONLY:
                if (optlen < sizeof(int) ||
                    inet_sk(sk)->inet_num)
                        goto e_inval;
                sk->sk_ipv6only = valbool;
                retv = 0;
                break;

        case IPV6_RECVPKTINFO:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxinfo = valbool;
                retv = 0;
                break;

        case IPV6_2292PKTINFO:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxoinfo = valbool;
                retv = 0;
                break;

        case IPV6_RECVHOPLIMIT:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxhlim = valbool;
                retv = 0;
                break;

        case IPV6_2292HOPLIMIT:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxohlim = valbool;
                retv = 0;
                break;

        case IPV6_RECVRTHDR:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.srcrt = valbool;
                retv = 0;
                break;

        case IPV6_2292RTHDR:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.osrcrt = valbool;
                retv = 0;
                break;

        case IPV6_RECVHOPOPTS:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.hopopts = valbool;
                retv = 0;
                break;

        case IPV6_2292HOPOPTS:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.ohopopts = valbool;
                retv = 0;
                break;

        case IPV6_RECVDSTOPTS:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.dstopts = valbool;
                retv = 0;
                break;

        case IPV6_2292DSTOPTS:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.odstopts = valbool;
                retv = 0;
                break;

        case IPV6_TCLASS:
                if (optlen < sizeof(int))
                        goto e_inval;
                if (val < -1 || val > 0xff)
                        goto e_inval;
                /* RFC 3542, 6.5: default traffic class of 0x0 */
                if (val == -1)
                        val = 0;
                if (sk->sk_type == SOCK_STREAM) {
                        val &= ~INET_ECN_MASK;
                        val |= np->tclass & INET_ECN_MASK;
                }
                if (np->tclass != val) {
                        np->tclass = val;
                        sk_dst_reset(sk);
                }
                retv = 0;
                break;

        case IPV6_RECVTCLASS:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxtclass = valbool;
                retv = 0;
                break;

        case IPV6_FLOWINFO:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxflow = valbool;
                retv = 0;
                break;

        case IPV6_RECVPATHMTU:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxpmtu = valbool;
                retv = 0;
                break;

        case IPV6_TRANSPARENT:
                if (valbool && !sockopt_ns_capable(net->user_ns, CAP_NET_RAW) &&
                    !sockopt_ns_capable(net->user_ns, CAP_NET_ADMIN)) {
                        retv = -EPERM;
                        break;
                }
                if (optlen < sizeof(int))
                        goto e_inval;
                /* we don't have a separate transparent bit for IPV6 we use the one in the IPv4 socket */
                inet_assign_bit(TRANSPARENT, sk, valbool);
                retv = 0;
                break;

        case IPV6_FREEBIND:
                if (optlen < sizeof(int))
                        goto e_inval;
                /* we also don't have a separate freebind bit for IPV6 */
                inet_assign_bit(FREEBIND, sk, valbool);
                retv = 0;
                break;

        case IPV6_RECVORIGDSTADDR:
                if (optlen < sizeof(int))
                        goto e_inval;
                np->rxopt.bits.rxorigdstaddr = valbool;
                retv = 0;
                break;

        case IPV6_HOPOPTS:
        case IPV6_RTHDRDSTOPTS:
        case IPV6_RTHDR:
        case IPV6_DSTOPTS:
                retv = ipv6_set_opt_hdr(sk, optname, optval, optlen);
                break;

        case IPV6_PKTINFO:
        {
                struct in6_pktinfo pkt;

                if (optlen == 0)
                        goto e_inval;
                else if (optlen < sizeof(struct in6_pktinfo) ||
                         sockptr_is_null(optval))
                        goto e_inval;

                if (copy_from_sockptr(&pkt, optval, sizeof(pkt))) {
                        retv = -EFAULT;
                        break;
                }
                if (!sk_dev_equal_l3scope(sk, pkt.ipi6_ifindex))
                        goto e_inval;

                np->sticky_pktinfo.ipi6_ifindex = pkt.ipi6_ifindex;
                np->sticky_pktinfo.ipi6_addr = pkt.ipi6_addr;
                retv = 0;
                break;
        }

        case IPV6_2292PKTOPTIONS:
        {
                struct ipv6_txoptions *opt = NULL;
                struct msghdr msg;
                struct flowi6 fl6;
                struct ipcm6_cookie ipc6;

                memset(&fl6, 0, sizeof(fl6));
                fl6.flowi6_oif = sk->sk_bound_dev_if;
                fl6.flowi6_mark = sk->sk_mark;

                if (optlen == 0)
                        goto update;

                /* 1K is probably excessive
                 * 1K is surely not enough, 2K per standard header is 16K.
                 */
                retv = -EINVAL;
                if (optlen > 64*1024)
                        break;

                opt = sock_kmalloc(sk, sizeof(*opt) + optlen, GFP_KERNEL);
                retv = -ENOBUFS;
                if (!opt)
                        break;

                memset(opt, 0, sizeof(*opt));
                refcount_set(&opt->refcnt, 1);
                opt->tot_len = sizeof(*opt) + optlen;
                retv = -EFAULT;
                if (copy_from_sockptr(opt + 1, optval, optlen))
                        goto done;

                msg.msg_controllen = optlen;
                msg.msg_control_is_user = false;
                msg.msg_control = (void *)(opt+1);
                ipc6.opt = opt;

                retv = ip6_datagram_send_ctl(net, sk, &msg, &fl6, &ipc6);
                if (retv)
                        goto done;
update:
                retv = 0;
                opt = ipv6_update_options(sk, opt);
done:
                if (opt) {
                        atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
                        txopt_put(opt);
                }
                break;
        }

        case IPV6_ADD_MEMBERSHIP:
        case IPV6_DROP_MEMBERSHIP:
        {
                struct ipv6_mreq mreq;

                if (optlen < sizeof(struct ipv6_mreq))
                        goto e_inval;

                retv = -EPROTO;
                if (inet_test_bit(IS_ICSK, sk))
                        break;

                retv = -EFAULT;
                if (copy_from_sockptr(&mreq, optval, sizeof(struct ipv6_mreq)))
                        break;

                if (optname == IPV6_ADD_MEMBERSHIP)
                        retv = ipv6_sock_mc_join(sk, mreq.ipv6mr_ifindex, &mreq.ipv6mr_multiaddr);
                else
                        retv = ipv6_sock_mc_drop(sk, mreq.ipv6mr_ifindex, &mreq.ipv6mr_multiaddr);
                break;
        }
        case IPV6_JOIN_ANYCAST:
        case IPV6_LEAVE_ANYCAST:
        {
                struct ipv6_mreq mreq;

                if (optlen < sizeof(struct ipv6_mreq))
                        goto e_inval;

                retv = -EFAULT;
                if (copy_from_sockptr(&mreq, optval, sizeof(struct ipv6_mreq)))
                        break;

                if (optname == IPV6_JOIN_ANYCAST)
                        retv = ipv6_sock_ac_join(sk, mreq.ipv6mr_ifindex, &mreq.ipv6mr_acaddr);
                else
                        retv = ipv6_sock_ac_drop(sk, mreq.ipv6mr_ifindex, &mreq.ipv6mr_acaddr);
                break;
        }
        case MCAST_JOIN_GROUP:
        case MCAST_LEAVE_GROUP:
                if (in_compat_syscall())
                        retv = compat_ipv6_mcast_join_leave(sk, optname, optval,
                                                            optlen);
                else
                        retv = ipv6_mcast_join_leave(sk, optname, optval,
                                                     optlen);
                break;
        case MCAST_JOIN_SOURCE_GROUP:
        case MCAST_LEAVE_SOURCE_GROUP:
        case MCAST_BLOCK_SOURCE:
        case MCAST_UNBLOCK_SOURCE:
                retv = do_ipv6_mcast_group_source(sk, optname, optval, optlen);
                break;
        case MCAST_MSFILTER:
                if (in_compat_syscall())
                        retv = compat_ipv6_set_mcast_msfilter(sk, optval,
                                                              optlen);
                else
                        retv = ipv6_set_mcast_msfilter(sk, optval, optlen);
                break;
        case IPV6_ROUTER_ALERT:
                if (optlen < sizeof(int))
                        goto e_inval;
                retv = ip6_ra_control(sk, val);
                if (retv == 0)
                        inet6_assign_bit(RTALERT, sk, valbool);
                break;
        case IPV6_FLOWLABEL_MGR:
                retv = ipv6_flowlabel_opt(sk, optval, optlen);
                break;
        case IPV6_IPSEC_POLICY:
        case IPV6_XFRM_POLICY:
                retv = -EPERM;
                if (!sockopt_ns_capable(net->user_ns, CAP_NET_ADMIN))
                        break;
                retv = xfrm_user_policy(sk, optname, optval, optlen);
                break;

        case IPV6_RECVFRAGSIZE:
                np->rxopt.bits.recvfragsize = valbool;
                retv = 0;
                break;
        }

unlock:
        sockopt_release_sock(sk);

        return retv;

e_inval:
        retv = -EINVAL;
        goto unlock;
}

int ipv6_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
                    unsigned int optlen)
{
        int err;

        if (level == SOL_IP && sk->sk_type != SOCK_RAW)
                return ip_setsockopt(sk, level, optname, optval, optlen);

        if (level != SOL_IPV6)
                return -ENOPROTOOPT;

        err = do_ipv6_setsockopt(sk, level, optname, optval, optlen);
#ifdef CONFIG_NETFILTER
        /* we need to exclude all possible ENOPROTOOPTs except default case */
        if (err == -ENOPROTOOPT && optname != IPV6_IPSEC_POLICY &&
                        optname != IPV6_XFRM_POLICY)
                err = nf_setsockopt(sk, PF_INET6, optname, optval, optlen);
#endif
        return err;
}
EXPORT_SYMBOL(ipv6_setsockopt);

static int ipv6_getsockopt_sticky(struct sock *sk, struct ipv6_txoptions *opt,
                                  int optname, sockptr_t optval, int len)
{
        struct ipv6_opt_hdr *hdr;

        if (!opt)
                return 0;

        switch (optname) {
        case IPV6_HOPOPTS:
                hdr = opt->hopopt;
                break;
        case IPV6_RTHDRDSTOPTS:
                hdr = opt->dst0opt;
                break;
        case IPV6_RTHDR:
                hdr = (struct ipv6_opt_hdr *)opt->srcrt;
                break;
        case IPV6_DSTOPTS:
                hdr = opt->dst1opt;
                break;
        default:
                return -EINVAL; /* should not happen */
        }

        if (!hdr)
                return 0;

        len = min_t(unsigned int, len, ipv6_optlen(hdr));
        if (copy_to_sockptr(optval, hdr, len))
                return -EFAULT;
        return len;
}

static int ipv6_get_msfilter(struct sock *sk, sockptr_t optval,
                             sockptr_t optlen, int len)
{
        const int size0 = offsetof(struct group_filter, gf_slist_flex);
        struct group_filter gsf;
        int num;
        int err;

        if (len < size0)
                return -EINVAL;
        if (copy_from_sockptr(&gsf, optval, size0))
                return -EFAULT;
        if (gsf.gf_group.ss_family != AF_INET6)
                return -EADDRNOTAVAIL;
        num = gsf.gf_numsrc;
        sockopt_lock_sock(sk);
        err = ip6_mc_msfget(sk, &gsf, optval, size0);
        if (!err) {
                if (num > gsf.gf_numsrc)
                        num = gsf.gf_numsrc;
                len = GROUP_FILTER_SIZE(num);
                if (copy_to_sockptr(optlen, &len, sizeof(int)) ||
                    copy_to_sockptr(optval, &gsf, size0))
                        err = -EFAULT;
        }
        sockopt_release_sock(sk);
        return err;
}

static int compat_ipv6_get_msfilter(struct sock *sk, sockptr_t optval,
                                    sockptr_t optlen, int len)
{
        const int size0 = offsetof(struct compat_group_filter, gf_slist_flex);
        struct compat_group_filter gf32;
        struct group_filter gf;
        int err;
        int num;

        if (len < size0)
                return -EINVAL;

        if (copy_from_sockptr(&gf32, optval, size0))
                return -EFAULT;
        gf.gf_interface = gf32.gf_interface;
        gf.gf_fmode = gf32.gf_fmode;
        num = gf.gf_numsrc = gf32.gf_numsrc;
        gf.gf_group = gf32.gf_group;

        if (gf.gf_group.ss_family != AF_INET6)
                return -EADDRNOTAVAIL;

        sockopt_lock_sock(sk);
        err = ip6_mc_msfget(sk, &gf, optval, size0);
        sockopt_release_sock(sk);
        if (err)
                return err;
        if (num > gf.gf_numsrc)
                num = gf.gf_numsrc;
        len = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32));
        if (copy_to_sockptr(optlen, &len, sizeof(int)) ||
            copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode),
                                   &gf.gf_fmode, sizeof(gf32.gf_fmode)) ||
            copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc),
                                   &gf.gf_numsrc, sizeof(gf32.gf_numsrc)))
                return -EFAULT;
        return 0;
}

int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
                       sockptr_t optval, sockptr_t optlen)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        int len;
        int val;

        if (ip6_mroute_opt(optname))
                return ip6_mroute_getsockopt(sk, optname, optval, optlen);

        if (copy_from_sockptr(&len, optlen, sizeof(int)))
                return -EFAULT;
        switch (optname) {
        case IPV6_ADDRFORM:
                if (sk->sk_protocol != IPPROTO_UDP &&
                    sk->sk_protocol != IPPROTO_UDPLITE &&
                    sk->sk_protocol != IPPROTO_TCP)
                        return -ENOPROTOOPT;
                if (sk->sk_state != TCP_ESTABLISHED)
                        return -ENOTCONN;
                val = sk->sk_family;
                break;
        case MCAST_MSFILTER:
                if (in_compat_syscall())
                        return compat_ipv6_get_msfilter(sk, optval, optlen, len);
                return ipv6_get_msfilter(sk, optval, optlen, len);
        case IPV6_2292PKTOPTIONS:
        {
                struct msghdr msg;
                struct sk_buff *skb;

                if (sk->sk_type != SOCK_STREAM)
                        return -ENOPROTOOPT;

                if (optval.is_kernel) {
                        msg.msg_control_is_user = false;
                        msg.msg_control = optval.kernel;
                } else {
                        msg.msg_control_is_user = true;
                        msg.msg_control_user = optval.user;
                }
                msg.msg_controllen = len;
                msg.msg_flags = 0;

                sockopt_lock_sock(sk);
                skb = np->pktoptions;
                if (skb)
                        ip6_datagram_recv_ctl(sk, &msg, skb);
                sockopt_release_sock(sk);
                if (!skb) {
                        if (np->rxopt.bits.rxinfo) {
                                int mcast_oif = READ_ONCE(np->mcast_oif);
                                struct in6_pktinfo src_info;

                                src_info.ipi6_ifindex = mcast_oif ? :
                                        np->sticky_pktinfo.ipi6_ifindex;
                                src_info.ipi6_addr = mcast_oif ? sk->sk_v6_daddr : np->sticky_pktinfo.ipi6_addr;
                                put_cmsg(&msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
                        }
                        if (np->rxopt.bits.rxhlim) {
                                int hlim = READ_ONCE(np->mcast_hops);

                                put_cmsg(&msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
                        }
                        if (np->rxopt.bits.rxtclass) {
                                int tclass = (int)ip6_tclass(np->rcv_flowinfo);

                                put_cmsg(&msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
                        }
                        if (np->rxopt.bits.rxoinfo) {
                                int mcast_oif = READ_ONCE(np->mcast_oif);
                                struct in6_pktinfo src_info;

                                src_info.ipi6_ifindex = mcast_oif ? :
                                        np->sticky_pktinfo.ipi6_ifindex;
                                src_info.ipi6_addr = mcast_oif ? sk->sk_v6_daddr :
                                                                 np->sticky_pktinfo.ipi6_addr;
                                put_cmsg(&msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
                        }
                        if (np->rxopt.bits.rxohlim) {
                                int hlim = READ_ONCE(np->mcast_hops);

                                put_cmsg(&msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
                        }
                        if (np->rxopt.bits.rxflow) {
                                __be32 flowinfo = np->rcv_flowinfo;

                                put_cmsg(&msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
                        }
                }
                len -= msg.msg_controllen;
                return copy_to_sockptr(optlen, &len, sizeof(int));
        }
        case IPV6_MTU:
        {
                struct dst_entry *dst;

                val = 0;
                rcu_read_lock();
                dst = __sk_dst_get(sk);
                if (dst)
                        val = dst6_mtu(dst);
                rcu_read_unlock();
                if (!val)
                        return -ENOTCONN;
                break;
        }

        case IPV6_V6ONLY:
                val = sk->sk_ipv6only;
                break;

        case IPV6_RECVPKTINFO:
                val = np->rxopt.bits.rxinfo;
                break;

        case IPV6_2292PKTINFO:
                val = np->rxopt.bits.rxoinfo;
                break;

        case IPV6_RECVHOPLIMIT:
                val = np->rxopt.bits.rxhlim;
                break;

        case IPV6_2292HOPLIMIT:
                val = np->rxopt.bits.rxohlim;
                break;

        case IPV6_RECVRTHDR:
                val = np->rxopt.bits.srcrt;
                break;

        case IPV6_2292RTHDR:
                val = np->rxopt.bits.osrcrt;
                break;

        case IPV6_HOPOPTS:
        case IPV6_RTHDRDSTOPTS:
        case IPV6_RTHDR:
        case IPV6_DSTOPTS:
        {
                struct ipv6_txoptions *opt;

                sockopt_lock_sock(sk);
                opt = rcu_dereference_protected(np->opt,
                                                lockdep_sock_is_held(sk));
                len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len);
                sockopt_release_sock(sk);
                /* check if ipv6_getsockopt_sticky() returns err code */
                if (len < 0)
                        return len;
                return copy_to_sockptr(optlen, &len, sizeof(int));
        }

        case IPV6_RECVHOPOPTS:
                val = np->rxopt.bits.hopopts;
                break;

        case IPV6_2292HOPOPTS:
                val = np->rxopt.bits.ohopopts;
                break;

        case IPV6_RECVDSTOPTS:
                val = np->rxopt.bits.dstopts;
                break;

        case IPV6_2292DSTOPTS:
                val = np->rxopt.bits.odstopts;
                break;

        case IPV6_TCLASS:
                val = np->tclass;
                break;

        case IPV6_RECVTCLASS:
                val = np->rxopt.bits.rxtclass;
                break;

        case IPV6_FLOWINFO:
                val = np->rxopt.bits.rxflow;
                break;

        case IPV6_RECVPATHMTU:
                val = np->rxopt.bits.rxpmtu;
                break;

        case IPV6_PATHMTU:
        {
                struct dst_entry *dst;
                struct ip6_mtuinfo mtuinfo;

                if (len < sizeof(mtuinfo))
                        return -EINVAL;

                len = sizeof(mtuinfo);
                memset(&mtuinfo, 0, sizeof(mtuinfo));

                rcu_read_lock();
                dst = __sk_dst_get(sk);
                if (dst)
                        mtuinfo.ip6m_mtu = dst6_mtu(dst);
                rcu_read_unlock();
                if (!mtuinfo.ip6m_mtu)
                        return -ENOTCONN;

                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, &mtuinfo, len))
                        return -EFAULT;

                return 0;
        }

        case IPV6_TRANSPARENT:
                val = inet_test_bit(TRANSPARENT, sk);
                break;

        case IPV6_FREEBIND:
                val = inet_test_bit(FREEBIND, sk);
                break;

        case IPV6_RECVORIGDSTADDR:
                val = np->rxopt.bits.rxorigdstaddr;
                break;

        case IPV6_UNICAST_HOPS:
        case IPV6_MULTICAST_HOPS:
        {
                struct dst_entry *dst;

                if (optname == IPV6_UNICAST_HOPS)
                        val = READ_ONCE(np->hop_limit);
                else
                        val = READ_ONCE(np->mcast_hops);

                if (val < 0) {
                        rcu_read_lock();
                        dst = __sk_dst_get(sk);
                        if (dst)
                                val = ip6_dst_hoplimit(dst);
                        rcu_read_unlock();
                }

                if (val < 0)
                        val = READ_ONCE(sock_net(sk)->ipv6.devconf_all->hop_limit);
                break;
        }

        case IPV6_MULTICAST_LOOP:
                val = inet6_test_bit(MC6_LOOP, sk);
                break;

        case IPV6_MULTICAST_IF:
                val = READ_ONCE(np->mcast_oif);
                break;

        case IPV6_MULTICAST_ALL:
                val = inet6_test_bit(MC6_ALL, sk);
                break;

        case IPV6_UNICAST_IF:
                val = (__force int)htonl((__u32) READ_ONCE(np->ucast_oif));
                break;

        case IPV6_MTU_DISCOVER:
                val = READ_ONCE(np->pmtudisc);
                break;

        case IPV6_RECVERR:
                val = inet6_test_bit(RECVERR6, sk);
                break;

        case IPV6_FLOWINFO_SEND:
                val = inet6_test_bit(SNDFLOW, sk);
                break;

        case IPV6_FLOWLABEL_MGR:
        {
                struct in6_flowlabel_req freq;
                int flags;

                if (len < sizeof(freq))
                        return -EINVAL;

                if (copy_from_sockptr(&freq, optval, sizeof(freq)))
                        return -EFAULT;

                if (freq.flr_action != IPV6_FL_A_GET)
                        return -EINVAL;

                len = sizeof(freq);
                flags = freq.flr_flags;

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

                val = ipv6_flowlabel_opt_get(sk, &freq, flags);
                if (val < 0)
                        return val;

                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, &freq, len))
                        return -EFAULT;

                return 0;
        }

        case IPV6_ADDR_PREFERENCES:
                {
                u8 srcprefs = READ_ONCE(np->srcprefs);
                val = 0;

                if (srcprefs & IPV6_PREFER_SRC_TMP)
                        val |= IPV6_PREFER_SRC_TMP;
                else if (srcprefs & IPV6_PREFER_SRC_PUBLIC)
                        val |= IPV6_PREFER_SRC_PUBLIC;
                else {
                        /* XXX: should we return system default? */
                        val |= IPV6_PREFER_SRC_PUBTMP_DEFAULT;
                }

                if (srcprefs & IPV6_PREFER_SRC_COA)
                        val |= IPV6_PREFER_SRC_COA;
                else
                        val |= IPV6_PREFER_SRC_HOME;
                break;
                }
        case IPV6_MINHOPCOUNT:
                val = READ_ONCE(np->min_hopcount);
                break;

        case IPV6_DONTFRAG:
                val = inet6_test_bit(DONTFRAG, sk);
                break;

        case IPV6_AUTOFLOWLABEL:
                val = ip6_autoflowlabel(sock_net(sk), sk);
                break;

        case IPV6_RECVFRAGSIZE:
                val = np->rxopt.bits.recvfragsize;
                break;

        case IPV6_ROUTER_ALERT:
                val = inet6_test_bit(RTALERT, sk);
                break;

        case IPV6_ROUTER_ALERT_ISOLATE:
                val = inet6_test_bit(RTALERT_ISOLATE, sk);
                break;

        case IPV6_RECVERR_RFC4884:
                val = inet6_test_bit(RECVERR6_RFC4884, sk);
                break;

        default:
                return -ENOPROTOOPT;
        }
        len = min_t(unsigned int, sizeof(int), len);
        if (copy_to_sockptr(optlen, &len, sizeof(int)))
                return -EFAULT;
        if (copy_to_sockptr(optval, &val, len))
                return -EFAULT;
        return 0;
}

int ipv6_getsockopt(struct sock *sk, int level, int optname,
                    char __user *optval, int __user *optlen)
{
        int err;

        if (level == SOL_IP && sk->sk_type != SOCK_RAW)
                return ip_getsockopt(sk, level, optname, optval, optlen);

        if (level != SOL_IPV6)
                return -ENOPROTOOPT;

        err = do_ipv6_getsockopt(sk, level, optname,
                                 USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
#ifdef CONFIG_NETFILTER
        /* we need to exclude all possible ENOPROTOOPTs except default case */
        if (err == -ENOPROTOOPT && optname != IPV6_2292PKTOPTIONS) {
                int len;

                if (get_user(len, optlen))
                        return -EFAULT;

                err = nf_getsockopt(sk, PF_INET6, optname, optval, &len);
                if (err >= 0)
                        err = put_user(len, optlen);
        }
#endif
        return err;
}
EXPORT_SYMBOL(ipv6_getsockopt);