// SPDX-License-Identifier: GPL-2.0-only
/*
 * IPv6 library code, needed by static components when full IPv6 support is
 * not configured or static.
 */

#include <linux/export.h>
#include <net/ipv6.h>
#include <net/ipv6_stubs.h>
#include <net/addrconf.h>
#include <net/ip.h>

/* if ipv6 module registers this function is used by xfrm to force all
 * sockets to relookup their nodes - this is fairly expensive, be
 * careful
 */
void (*__fib6_flush_trees)(struct net *);
EXPORT_SYMBOL(__fib6_flush_trees);

#define IPV6_ADDR_SCOPE_TYPE(scope)     ((scope) << 16)

static inline unsigned int ipv6_addr_scope2type(unsigned int scope)
{
        switch (scope) {
        case IPV6_ADDR_SCOPE_NODELOCAL:
                return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_NODELOCAL) |
                        IPV6_ADDR_LOOPBACK);
        case IPV6_ADDR_SCOPE_LINKLOCAL:
                return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL) |
                        IPV6_ADDR_LINKLOCAL);
        case IPV6_ADDR_SCOPE_SITELOCAL:
                return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL) |
                        IPV6_ADDR_SITELOCAL);
        }
        return IPV6_ADDR_SCOPE_TYPE(scope);
}

int __ipv6_addr_type(const struct in6_addr *addr)
{
        __be32 st;

        st = addr->s6_addr32[0];

        /* Consider all addresses with the first three bits different of
           000 and 111 as unicasts.
         */
        if ((st & htonl(0xE0000000)) != htonl(0x00000000) &&
            (st & htonl(0xE0000000)) != htonl(0xE0000000))
                return (IPV6_ADDR_UNICAST |
                        IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));

        if ((st & htonl(0xFF000000)) == htonl(0xFF000000)) {
                /* multicast */
                /* addr-select 3.1 */
                return (IPV6_ADDR_MULTICAST |
                        ipv6_addr_scope2type(IPV6_ADDR_MC_SCOPE(addr)));
        }

        if ((st & htonl(0xFFC00000)) == htonl(0xFE800000))
                return (IPV6_ADDR_LINKLOCAL | IPV6_ADDR_UNICAST |
                        IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL));               /* addr-select 3.1 */
        if ((st & htonl(0xFFC00000)) == htonl(0xFEC00000))
                return (IPV6_ADDR_SITELOCAL | IPV6_ADDR_UNICAST |
                        IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL));               /* addr-select 3.1 */
        if ((st & htonl(0xFE000000)) == htonl(0xFC000000))
                return (IPV6_ADDR_UNICAST |
                        IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));                  /* RFC 4193 */

        if ((addr->s6_addr32[0] | addr->s6_addr32[1]) == 0) {
                if (addr->s6_addr32[2] == 0) {
                        if (addr->s6_addr32[3] == 0)
                                return IPV6_ADDR_ANY;

                        if (addr->s6_addr32[3] == htonl(0x00000001))
                                return (IPV6_ADDR_LOOPBACK | IPV6_ADDR_UNICAST |
                                        IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL));       /* addr-select 3.4 */

                        return (IPV6_ADDR_COMPATv4 | IPV6_ADDR_UNICAST |
                                IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));  /* addr-select 3.3 */
                }

                if (addr->s6_addr32[2] == htonl(0x0000ffff))
                        return (IPV6_ADDR_MAPPED |
                                IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));  /* addr-select 3.3 */
        }

        return (IPV6_ADDR_UNICAST |
                IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));  /* addr-select 3.4 */
}
EXPORT_SYMBOL(__ipv6_addr_type);

static ATOMIC_NOTIFIER_HEAD(inet6addr_chain);
static BLOCKING_NOTIFIER_HEAD(inet6addr_validator_chain);

int register_inet6addr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&inet6addr_chain, nb);
}
EXPORT_SYMBOL(register_inet6addr_notifier);

int unregister_inet6addr_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&inet6addr_chain, nb);
}
EXPORT_SYMBOL(unregister_inet6addr_notifier);

int inet6addr_notifier_call_chain(unsigned long val, void *v)
{
        return atomic_notifier_call_chain(&inet6addr_chain, val, v);
}
EXPORT_SYMBOL(inet6addr_notifier_call_chain);

int register_inet6addr_validator_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&inet6addr_validator_chain, nb);
}
EXPORT_SYMBOL(register_inet6addr_validator_notifier);

int unregister_inet6addr_validator_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&inet6addr_validator_chain,
                                                  nb);
}
EXPORT_SYMBOL(unregister_inet6addr_validator_notifier);

int inet6addr_validator_notifier_call_chain(unsigned long val, void *v)
{
        return blocking_notifier_call_chain(&inet6addr_validator_chain, val, v);
}
EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);

static struct dst_entry *eafnosupport_ipv6_dst_lookup_flow(struct net *net,
                                                           const struct sock *sk,
                                                           struct flowi6 *fl6,
                                                           const struct in6_addr *final_dst)
{
        return ERR_PTR(-EAFNOSUPPORT);
}

static int eafnosupport_ipv6_route_input(struct sk_buff *skb)
{
        return -EAFNOSUPPORT;
}

static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
{
        return NULL;
}

static int
eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
                               int oif, struct flowi6 *fl6,
                               struct fib6_result *res, int flags)
{
        return -EAFNOSUPPORT;
}

static int
eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
                         struct fib6_result *res, int flags)
{
        return -EAFNOSUPPORT;
}

static void
eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
                              struct flowi6 *fl6, int oif, bool have_oif_match,
                              const struct sk_buff *skb, int strict)
{
}

static u32
eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
                               const struct in6_addr *daddr,
                               const struct in6_addr *saddr)
{
        return 0;
}

static int eafnosupport_fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
                                     struct fib6_config *cfg, gfp_t gfp_flags,
                                     struct netlink_ext_ack *extack)
{
        NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
        return -EAFNOSUPPORT;
}

static int eafnosupport_ip6_del_rt(struct net *net, struct fib6_info *rt,
                                   bool skip_notify)
{
        return -EAFNOSUPPORT;
}

static int eafnosupport_ipv6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
                                      int (*output)(struct net *, struct sock *, struct sk_buff *))
{
        kfree_skb(skb);
        return -EAFNOSUPPORT;
}

static struct net_device *eafnosupport_ipv6_dev_find(struct net *net, const struct in6_addr *addr,
                                                     struct net_device *dev)
{
        return ERR_PTR(-EAFNOSUPPORT);
}

const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
        .ipv6_dst_lookup_flow = eafnosupport_ipv6_dst_lookup_flow,
        .ipv6_route_input  = eafnosupport_ipv6_route_input,
        .fib6_get_table    = eafnosupport_fib6_get_table,
        .fib6_table_lookup = eafnosupport_fib6_table_lookup,
        .fib6_lookup       = eafnosupport_fib6_lookup,
        .fib6_select_path  = eafnosupport_fib6_select_path,
        .ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
        .fib6_nh_init      = eafnosupport_fib6_nh_init,
        .ip6_del_rt        = eafnosupport_ip6_del_rt,
        .ipv6_fragment     = eafnosupport_ipv6_fragment,
        .ipv6_dev_find     = eafnosupport_ipv6_dev_find,
};
EXPORT_SYMBOL_GPL(ipv6_stub);

/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
const struct in6_addr in6addr_loopback __aligned(BITS_PER_LONG/8)
        = IN6ADDR_LOOPBACK_INIT;
EXPORT_SYMBOL(in6addr_loopback);
const struct in6_addr in6addr_any __aligned(BITS_PER_LONG/8)
        = IN6ADDR_ANY_INIT;
EXPORT_SYMBOL(in6addr_any);
const struct in6_addr in6addr_linklocal_allnodes __aligned(BITS_PER_LONG/8)
        = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allnodes);
const struct in6_addr in6addr_linklocal_allrouters __aligned(BITS_PER_LONG/8)
        = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allrouters);
const struct in6_addr in6addr_interfacelocal_allnodes __aligned(BITS_PER_LONG/8)
        = IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allnodes);
const struct in6_addr in6addr_interfacelocal_allrouters __aligned(BITS_PER_LONG/8)
        = IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allrouters);
const struct in6_addr in6addr_sitelocal_allrouters __aligned(BITS_PER_LONG/8)
        = IN6ADDR_SITELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_sitelocal_allrouters);

static void snmp6_free_dev(struct inet6_dev *idev)
{
        kfree(idev->stats.icmpv6msgdev);
        kfree(idev->stats.icmpv6dev);
        free_percpu(idev->stats.ipv6);
}

static void in6_dev_finish_destroy_rcu(struct rcu_head *head)
{
        struct inet6_dev *idev = container_of(head, struct inet6_dev, rcu);

        snmp6_free_dev(idev);
        kfree(idev);
}

/* Nobody refers to this device, we may destroy it. */

void in6_dev_finish_destroy(struct inet6_dev *idev)
{
        struct net_device *dev = idev->dev;

        WARN_ON(!list_empty(&idev->addr_list));
        WARN_ON(rcu_access_pointer(idev->mc_list));
        WARN_ON(timer_pending(&idev->rs_timer));

#ifdef NET_REFCNT_DEBUG
        pr_debug("%s: %s\n", __func__, dev ? dev->name : "NIL");
#endif
        netdev_put(dev, &idev->dev_tracker);
        if (!idev->dead) {
                pr_warn("Freeing alive inet6 device %p\n", idev);
                return;
        }
        call_rcu(&idev->rcu, in6_dev_finish_destroy_rcu);
}
EXPORT_SYMBOL(in6_dev_finish_destroy);