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root/net/ipv6/ndisc.c

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DEFINITIONS

This source file includes following definitions.
  1. ndisc_addr_option_pad
  2. ndisc_opt_addr_space
  3. ndisc_fill_addr_option
  4. ndisc_next_option
  5. ndisc_is_useropt
  6. ndisc_next_useropt
  7. ndisc_parse_options
  8. ndisc_opt_addr_data
  9. ndisc_mc_map
  10. ndisc_hash
  11. ndisc_constructor
  12. pndisc_constructor
  13. pndisc_destructor
  14. __ndisc_send
  15. ndisc_send_na
  16. ndisc_send_ns
  17. ndisc_send_rs
  18. ndisc_error_report
  19. ndisc_solicit
  20. pndisc_is_router
  21. ndisc_recv_ns
  22. ndisc_recv_na
  23. ndisc_recv_rs
  24. ndisc_ra_useropt
  25. ndisc_router_discovery
  26. ndisc_redirect_rcv
  27. ndisc_send_redirect
  28. pndisc_redo
  29. ndisc_rcv
  30. ndisc_netdev_event
  31. ndisc_warn_deprecated_sysctl
  32. ndisc_ifinfo_sysctl_change
  33. ndisc_ifinfo_sysctl_strategy
  34. ndisc_net_init
  35. ndisc_net_exit
  36. ndisc_init
  37. ndisc_cleanup

/*
 *      Neighbour Discovery for IPv6
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Mike Shaver             <shaver@ingenia.com>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/*
 *      Changes:
 *
 *      Pierre Ynard                    :       export userland ND options
 *                                              through netlink (RDNSS support)
 *      Lars Fenneberg                  :       fixed MTU setting on receipt
 *                                              of an RA.
 *      Janos Farkas                    :       kmalloc failure checks
 *      Alexey Kuznetsov                :       state machine reworked
 *                                              and moved to net/core.
 *      Pekka Savola                    :       RFC2461 validation
 *      YOSHIFUJI Hideaki @USAGI        :       Verify ND options properly
 */

/* Set to 3 to get tracing... */
#define ND_DEBUG 1

#define ND_PRINTK(fmt, args...) do { if (net_ratelimit()) { printk(fmt, ## args); } } while(0)
#define ND_NOPRINTK(x...) do { ; } while(0)
#define ND_PRINTK0 ND_PRINTK
#define ND_PRINTK1 ND_NOPRINTK
#define ND_PRINTK2 ND_NOPRINTK
#define ND_PRINTK3 ND_NOPRINTK
#if ND_DEBUG >= 1
#undef ND_PRINTK1
#define ND_PRINTK1 ND_PRINTK
#endif
#if ND_DEBUG >= 2
#undef ND_PRINTK2
#define ND_PRINTK2 ND_PRINTK
#endif
#if ND_DEBUG >= 3
#undef ND_PRINTK3
#define ND_PRINTK3 ND_PRINTK
#endif

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/sched.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/route.h>
#include <linux/init.h>
#include <linux/rcupdate.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

#include <linux/if_addr.h>
#include <linux/if_arp.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/jhash.h>

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

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/icmp.h>

#include <net/netlink.h>
#include <linux/rtnetlink.h>

#include <net/flow.h>
#include <net/ip6_checksum.h>
#include <net/inet_common.h>
#include <linux/proc_fs.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>

static u32 ndisc_hash(const void *pkey, const struct net_device *dev);
static int ndisc_constructor(struct neighbour *neigh);
static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
static int pndisc_constructor(struct pneigh_entry *n);
static void pndisc_destructor(struct pneigh_entry *n);
static void pndisc_redo(struct sk_buff *skb);

static struct neigh_ops ndisc_generic_ops = {
        .family =               AF_INET6,
        .solicit =              ndisc_solicit,
        .error_report =         ndisc_error_report,
        .output =               neigh_resolve_output,
        .connected_output =     neigh_connected_output,
        .hh_output =            dev_queue_xmit,
        .queue_xmit =           dev_queue_xmit,
};

static struct neigh_ops ndisc_hh_ops = {
        .family =               AF_INET6,
        .solicit =              ndisc_solicit,
        .error_report =         ndisc_error_report,
        .output =               neigh_resolve_output,
        .connected_output =     neigh_resolve_output,
        .hh_output =            dev_queue_xmit,
        .queue_xmit =           dev_queue_xmit,
};


static struct neigh_ops ndisc_direct_ops = {
        .family =               AF_INET6,
        .output =               dev_queue_xmit,
        .connected_output =     dev_queue_xmit,
        .hh_output =            dev_queue_xmit,
        .queue_xmit =           dev_queue_xmit,
};

struct neigh_table nd_tbl = {
        .family =       AF_INET6,
        .entry_size =   sizeof(struct neighbour) + sizeof(struct in6_addr),
        .key_len =      sizeof(struct in6_addr),
        .hash =         ndisc_hash,
        .constructor =  ndisc_constructor,
        .pconstructor = pndisc_constructor,
        .pdestructor =  pndisc_destructor,
        .proxy_redo =   pndisc_redo,
        .id =           "ndisc_cache",
        .parms = {
                .tbl =                  &nd_tbl,
                .base_reachable_time =  30 * HZ,
                .retrans_time =  1 * HZ,
                .gc_staletime = 60 * HZ,
                .reachable_time =               30 * HZ,
                .delay_probe_time =      5 * HZ,
                .queue_len =             3,
                .ucast_probes =  3,
                .mcast_probes =  3,
                .anycast_delay =         1 * HZ,
                .proxy_delay =          (8 * HZ) / 10,
                .proxy_qlen =           64,
        },
        .gc_interval =    30 * HZ,
        .gc_thresh1 =    128,
        .gc_thresh2 =    512,
        .gc_thresh3 =   1024,
};

/* ND options */
struct ndisc_options {
        struct nd_opt_hdr *nd_opt_array[__ND_OPT_ARRAY_MAX];
#ifdef CONFIG_IPV6_ROUTE_INFO
        struct nd_opt_hdr *nd_opts_ri;
        struct nd_opt_hdr *nd_opts_ri_end;
#endif
        struct nd_opt_hdr *nd_useropts;
        struct nd_opt_hdr *nd_useropts_end;
};

#define nd_opts_src_lladdr      nd_opt_array[ND_OPT_SOURCE_LL_ADDR]
#define nd_opts_tgt_lladdr      nd_opt_array[ND_OPT_TARGET_LL_ADDR]
#define nd_opts_pi              nd_opt_array[ND_OPT_PREFIX_INFO]
#define nd_opts_pi_end          nd_opt_array[__ND_OPT_PREFIX_INFO_END]
#define nd_opts_rh              nd_opt_array[ND_OPT_REDIRECT_HDR]
#define nd_opts_mtu             nd_opt_array[ND_OPT_MTU]

#define NDISC_OPT_SPACE(len) (((len)+2+7)&~7)

/*
 * Return the padding between the option length and the start of the
 * link addr.  Currently only IP-over-InfiniBand needs this, although
 * if RFC 3831 IPv6-over-Fibre Channel is ever implemented it may
 * also need a pad of 2.
 */
static int ndisc_addr_option_pad(unsigned short type)
{
        switch (type) {
        case ARPHRD_INFINIBAND: return 2;
        default:                return 0;
        }
}

static inline int ndisc_opt_addr_space(struct net_device *dev)
{
        return NDISC_OPT_SPACE(dev->addr_len + ndisc_addr_option_pad(dev->type));
}

static u8 *ndisc_fill_addr_option(u8 *opt, int type, void *data, int data_len,
                                  unsigned short addr_type)
{
        int space = NDISC_OPT_SPACE(data_len);
        int pad   = ndisc_addr_option_pad(addr_type);

        opt[0] = type;
        opt[1] = space>>3;

        memset(opt + 2, 0, pad);
        opt   += pad;
        space -= pad;

        memcpy(opt+2, data, data_len);
        data_len += 2;
        opt += data_len;
        if ((space -= data_len) > 0)
                memset(opt, 0, space);
        return opt + space;
}

static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
                                            struct nd_opt_hdr *end)
{
        int type;
        if (!cur || !end || cur >= end)
                return NULL;
        type = cur->nd_opt_type;
        do {
                cur = ((void *)cur) + (cur->nd_opt_len << 3);
        } while(cur < end && cur->nd_opt_type != type);
        return (cur <= end && cur->nd_opt_type == type ? cur : NULL);
}

static inline int ndisc_is_useropt(struct nd_opt_hdr *opt)
{
        return (opt->nd_opt_type == ND_OPT_RDNSS);
}

static struct nd_opt_hdr *ndisc_next_useropt(struct nd_opt_hdr *cur,
                                             struct nd_opt_hdr *end)
{
        if (!cur || !end || cur >= end)
                return NULL;
        do {
                cur = ((void *)cur) + (cur->nd_opt_len << 3);
        } while(cur < end && !ndisc_is_useropt(cur));
        return (cur <= end && ndisc_is_useropt(cur) ? cur : NULL);
}

static struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
                                                 struct ndisc_options *ndopts)
{
        struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;

        if (!nd_opt || opt_len < 0 || !ndopts)
                return NULL;
        memset(ndopts, 0, sizeof(*ndopts));
        while (opt_len) {
                int l;
                if (opt_len < sizeof(struct nd_opt_hdr))
                        return NULL;
                l = nd_opt->nd_opt_len << 3;
                if (opt_len < l || l == 0)
                        return NULL;
                switch (nd_opt->nd_opt_type) {
                case ND_OPT_SOURCE_LL_ADDR:
                case ND_OPT_TARGET_LL_ADDR:
                case ND_OPT_MTU:
                case ND_OPT_REDIRECT_HDR:
                        if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
                                ND_PRINTK2(KERN_WARNING
                                           "%s(): duplicated ND6 option found: type=%d\n",
                                           __func__,
                                           nd_opt->nd_opt_type);
                        } else {
                                ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
                        }
                        break;
                case ND_OPT_PREFIX_INFO:
                        ndopts->nd_opts_pi_end = nd_opt;
                        if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
                                ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
                        break;
#ifdef CONFIG_IPV6_ROUTE_INFO
                case ND_OPT_ROUTE_INFO:
                        ndopts->nd_opts_ri_end = nd_opt;
                        if (!ndopts->nd_opts_ri)
                                ndopts->nd_opts_ri = nd_opt;
                        break;
#endif
                default:
                        if (ndisc_is_useropt(nd_opt)) {
                                ndopts->nd_useropts_end = nd_opt;
                                if (!ndopts->nd_useropts)
                                        ndopts->nd_useropts = nd_opt;
                        } else {
                                /*
                                 * Unknown options must be silently ignored,
                                 * to accommodate future extension to the
                                 * protocol.
                                 */
                                ND_PRINTK2(KERN_NOTICE
                                           "%s(): ignored unsupported option; type=%d, len=%d\n",
                                           __func__,
                                           nd_opt->nd_opt_type, nd_opt->nd_opt_len);
                        }
                }
                opt_len -= l;
                nd_opt = ((void *)nd_opt) + l;
        }
        return ndopts;
}

static inline u8 *ndisc_opt_addr_data(struct nd_opt_hdr *p,
                                      struct net_device *dev)
{
        u8 *lladdr = (u8 *)(p + 1);
        int lladdrlen = p->nd_opt_len << 3;
        int prepad = ndisc_addr_option_pad(dev->type);
        if (lladdrlen != NDISC_OPT_SPACE(dev->addr_len + prepad))
                return NULL;
        return (lladdr + prepad);
}

int ndisc_mc_map(struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
{
        switch (dev->type) {
        case ARPHRD_ETHER:
        case ARPHRD_IEEE802:    /* Not sure. Check it later. --ANK */
        case ARPHRD_FDDI:
                ipv6_eth_mc_map(addr, buf);
                return 0;
        case ARPHRD_IEEE802_TR:
                ipv6_tr_mc_map(addr,buf);
                return 0;
        case ARPHRD_ARCNET:
                ipv6_arcnet_mc_map(addr, buf);
                return 0;
        case ARPHRD_INFINIBAND:
                ipv6_ib_mc_map(addr, dev->broadcast, buf);
                return 0;
        default:
                if (dir) {
                        memcpy(buf, dev->broadcast, dev->addr_len);
                        return 0;
                }
        }
        return -EINVAL;
}

EXPORT_SYMBOL(ndisc_mc_map);

static u32 ndisc_hash(const void *pkey, const struct net_device *dev)
{
        const u32 *p32 = pkey;
        u32 addr_hash, i;

        addr_hash = 0;
        for (i = 0; i < (sizeof(struct in6_addr) / sizeof(u32)); i++)
                addr_hash ^= *p32++;

        return jhash_2words(addr_hash, dev->ifindex, nd_tbl.hash_rnd);
}

static int ndisc_constructor(struct neighbour *neigh)
{
        struct in6_addr *addr = (struct in6_addr*)&neigh->primary_key;
        struct net_device *dev = neigh->dev;
        struct inet6_dev *in6_dev;
        struct neigh_parms *parms;
        int is_multicast = ipv6_addr_is_multicast(addr);

        rcu_read_lock();
        in6_dev = in6_dev_get(dev);
        if (in6_dev == NULL) {
                rcu_read_unlock();
                return -EINVAL;
        }

        parms = in6_dev->nd_parms;
        __neigh_parms_put(neigh->parms);
        neigh->parms = neigh_parms_clone(parms);
        rcu_read_unlock();

        neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
        if (!dev->header_ops) {
                neigh->nud_state = NUD_NOARP;
                neigh->ops = &ndisc_direct_ops;
                neigh->output = neigh->ops->queue_xmit;
        } else {
                if (is_multicast) {
                        neigh->nud_state = NUD_NOARP;
                        ndisc_mc_map(addr, neigh->ha, dev, 1);
                } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
                        neigh->nud_state = NUD_NOARP;
                        memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
                        if (dev->flags&IFF_LOOPBACK)
                                neigh->type = RTN_LOCAL;
                } else if (dev->flags&IFF_POINTOPOINT) {
                        neigh->nud_state = NUD_NOARP;
                        memcpy(neigh->ha, dev->broadcast, dev->addr_len);
                }
                if (dev->header_ops->cache)
                        neigh->ops = &ndisc_hh_ops;
                else
                        neigh->ops = &ndisc_generic_ops;
                if (neigh->nud_state&NUD_VALID)
                        neigh->output = neigh->ops->connected_output;
                else
                        neigh->output = neigh->ops->output;
        }
        in6_dev_put(in6_dev);
        return 0;
}

static int pndisc_constructor(struct pneigh_entry *n)
{
        struct in6_addr *addr = (struct in6_addr*)&n->key;
        struct in6_addr maddr;
        struct net_device *dev = n->dev;

        if (dev == NULL || __in6_dev_get(dev) == NULL)
                return -EINVAL;
        addrconf_addr_solict_mult(addr, &maddr);
        ipv6_dev_mc_inc(dev, &maddr);
        return 0;
}

static void pndisc_destructor(struct pneigh_entry *n)
{
        struct in6_addr *addr = (struct in6_addr*)&n->key;
        struct in6_addr maddr;
        struct net_device *dev = n->dev;

        if (dev == NULL || __in6_dev_get(dev) == NULL)
                return;
        addrconf_addr_solict_mult(addr, &maddr);
        ipv6_dev_mc_dec(dev, &maddr);
}

/*
 *      Send a Neighbour Advertisement
 */
static void __ndisc_send(struct net_device *dev,
                         struct neighbour *neigh,
                         const struct in6_addr *daddr,
                         const struct in6_addr *saddr,
                         struct icmp6hdr *icmp6h, const struct in6_addr *target,
                         int llinfo)
{
        struct flowi fl;
        struct dst_entry *dst;
        struct net *net = dev_net(dev);
        struct sock *sk = net->ipv6.ndisc_sk;
        struct sk_buff *skb;
        struct icmp6hdr *hdr;
        struct inet6_dev *idev;
        int len;
        int err;
        u8 *opt, type;

        type = icmp6h->icmp6_type;

        icmpv6_flow_init(sk, &fl, type, saddr, daddr, dev->ifindex);

        dst = icmp6_dst_alloc(dev, neigh, daddr);
        if (!dst)
                return;

        err = xfrm_lookup(&dst, &fl, NULL, 0);
        if (err < 0)
                return;

        if (!dev->addr_len)
                llinfo = 0;

        len = sizeof(struct icmp6hdr) + (target ? sizeof(*target) : 0);
        if (llinfo)
                len += ndisc_opt_addr_space(dev);

        skb = sock_alloc_send_skb(sk,
                                  (MAX_HEADER + sizeof(struct ipv6hdr) +
                                   len + LL_ALLOCATED_SPACE(dev)),
                                  1, &err);
        if (!skb) {
                ND_PRINTK0(KERN_ERR
                           "ICMPv6 ND: %s() failed to allocate an skb.\n",
                           __func__);
                dst_release(dst);
                return;
        }

        skb_reserve(skb, LL_RESERVED_SPACE(dev));
        ip6_nd_hdr(sk, skb, dev, saddr, daddr, IPPROTO_ICMPV6, len);

        skb->transport_header = skb->tail;
        skb_put(skb, len);

        hdr = (struct icmp6hdr *)skb_transport_header(skb);
        memcpy(hdr, icmp6h, sizeof(*hdr));

        opt = skb_transport_header(skb) + sizeof(struct icmp6hdr);
        if (target) {
                ipv6_addr_copy((struct in6_addr *)opt, target);
                opt += sizeof(*target);
        }

        if (llinfo)
                ndisc_fill_addr_option(opt, llinfo, dev->dev_addr,
                                       dev->addr_len, dev->type);

        hdr->icmp6_cksum = csum_ipv6_magic(saddr, daddr, len,
                                           IPPROTO_ICMPV6,
                                           csum_partial((__u8 *) hdr,
                                                        len, 0));

        skb->dst = dst;

        idev = in6_dev_get(dst->dev);
        IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);

        err = NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, dst->dev,
                      dst_output);
        if (!err) {
                ICMP6MSGOUT_INC_STATS(net, idev, type);
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
        }

        if (likely(idev != NULL))
                in6_dev_put(idev);
}

static void ndisc_send_na(struct net_device *dev, struct neighbour *neigh,
                          const struct in6_addr *daddr,
                          const struct in6_addr *solicited_addr,
                          int router, int solicited, int override, int inc_opt)
{
        struct in6_addr tmpaddr;
        struct inet6_ifaddr *ifp;
        const struct in6_addr *src_addr;
        struct icmp6hdr icmp6h = {
                .icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
        };

        /* for anycast or proxy, solicited_addr != src_addr */
        ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
        if (ifp) {
                src_addr = solicited_addr;
                if (ifp->flags & IFA_F_OPTIMISTIC)
                        override = 0;
                in6_ifa_put(ifp);
        } else {
                if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
                                       inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
                                       &tmpaddr))
                        return;
                src_addr = &tmpaddr;
        }

        icmp6h.icmp6_router = router;
        icmp6h.icmp6_solicited = solicited;
        icmp6h.icmp6_override = override;

        __ndisc_send(dev, neigh, daddr, src_addr,
                     &icmp6h, solicited_addr,
                     inc_opt ? ND_OPT_TARGET_LL_ADDR : 0);
}

void ndisc_send_ns(struct net_device *dev, struct neighbour *neigh,
                   const struct in6_addr *solicit,
                   const struct in6_addr *daddr, const struct in6_addr *saddr)
{
        struct in6_addr addr_buf;
        struct icmp6hdr icmp6h = {
                .icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
        };

        if (saddr == NULL) {
                if (ipv6_get_lladdr(dev, &addr_buf,
                                   (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)))
                        return;
                saddr = &addr_buf;
        }

        __ndisc_send(dev, neigh, daddr, saddr,
                     &icmp6h, solicit,
                     !ipv6_addr_any(saddr) ? ND_OPT_SOURCE_LL_ADDR : 0);
}

void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
                   const struct in6_addr *daddr)
{
        struct icmp6hdr icmp6h = {
                .icmp6_type = NDISC_ROUTER_SOLICITATION,
        };
        int send_sllao = dev->addr_len;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
        /*
         * According to section 2.2 of RFC 4429, we must not
         * send router solicitations with a sllao from
         * optimistic addresses, but we may send the solicitation
         * if we don't include the sllao.  So here we check
         * if our address is optimistic, and if so, we
         * suppress the inclusion of the sllao.
         */
        if (send_sllao) {
                struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
                                                           dev, 1);
                if (ifp) {
                        if (ifp->flags & IFA_F_OPTIMISTIC)  {
                                send_sllao = 0;
                        }
                        in6_ifa_put(ifp);
                } else {
                        send_sllao = 0;
                }
        }
#endif
        __ndisc_send(dev, NULL, daddr, saddr,
                     &icmp6h, NULL,
                     send_sllao ? ND_OPT_SOURCE_LL_ADDR : 0);
}


static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
{
        /*
         *      "The sender MUST return an ICMP
         *       destination unreachable"
         */
        dst_link_failure(skb);
        kfree_skb(skb);
}

/* Called with locked neigh: either read or both */

static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
{
        struct in6_addr *saddr = NULL;
        struct in6_addr mcaddr;
        struct net_device *dev = neigh->dev;
        struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
        int probes = atomic_read(&neigh->probes);

        if (skb && ipv6_chk_addr(dev_net(dev), &ipv6_hdr(skb)->saddr, dev, 1))
                saddr = &ipv6_hdr(skb)->saddr;

        if ((probes -= neigh->parms->ucast_probes) < 0) {
                if (!(neigh->nud_state & NUD_VALID)) {
                        ND_PRINTK1(KERN_DEBUG
                                   "%s(): trying to ucast probe in NUD_INVALID: "
                                   NIP6_FMT "\n",
                                   __func__,
                                   NIP6(*target));
                }
                ndisc_send_ns(dev, neigh, target, target, saddr);
        } else if ((probes -= neigh->parms->app_probes) < 0) {
#ifdef CONFIG_ARPD
                neigh_app_ns(neigh);
#endif
        } else {
                addrconf_addr_solict_mult(target, &mcaddr);
                ndisc_send_ns(dev, NULL, target, &mcaddr, saddr);
        }
}

static int pndisc_is_router(const void *pkey,
                            struct net_device *dev)
{
        struct pneigh_entry *n;
        int ret = -1;

        read_lock_bh(&nd_tbl.lock);
        n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
        if (n)
                ret = !!(n->flags & NTF_ROUTER);
        read_unlock_bh(&nd_tbl.lock);

        return ret;
}

static void ndisc_recv_ns(struct sk_buff *skb)
{
        struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
        struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
        struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
        u8 *lladdr = NULL;
        u32 ndoptlen = skb->tail - (skb->transport_header +
                                    offsetof(struct nd_msg, opt));
        struct ndisc_options ndopts;
        struct net_device *dev = skb->dev;
        struct inet6_ifaddr *ifp;
        struct inet6_dev *idev = NULL;
        struct neighbour *neigh;
        int dad = ipv6_addr_any(saddr);
        int inc;
        int is_router = -1;

        if (ipv6_addr_is_multicast(&msg->target)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NS: multicast target address");
                return;
        }

        /*
         * RFC2461 7.1.1:
         * DAD has to be destined for solicited node multicast address.
         */
        if (dad &&
            !(daddr->s6_addr32[0] == htonl(0xff020000) &&
              daddr->s6_addr32[1] == htonl(0x00000000) &&
              daddr->s6_addr32[2] == htonl(0x00000001) &&
              daddr->s6_addr [12] == 0xff )) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NS: bad DAD packet (wrong destination)\n");
                return;
        }

        if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NS: invalid ND options\n");
                return;
        }

        if (ndopts.nd_opts_src_lladdr) {
                lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
                if (!lladdr) {
                        ND_PRINTK2(KERN_WARNING
                                   "ICMPv6 NS: invalid link-layer address length\n");
                        return;
                }

                /* RFC2461 7.1.1:
                 *      If the IP source address is the unspecified address,
                 *      there MUST NOT be source link-layer address option
                 *      in the message.
                 */
                if (dad) {
                        ND_PRINTK2(KERN_WARNING
                                   "ICMPv6 NS: bad DAD packet (link-layer address option)\n");
                        return;
                }
        }

        inc = ipv6_addr_is_multicast(daddr);

        ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
        if (ifp) {

                if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
                        if (dad) {
                                if (dev->type == ARPHRD_IEEE802_TR) {
                                        const unsigned char *sadr;
                                        sadr = skb_mac_header(skb);
                                        if (((sadr[8] ^ dev->dev_addr[0]) & 0x7f) == 0 &&
                                            sadr[9] == dev->dev_addr[1] &&
                                            sadr[10] == dev->dev_addr[2] &&
                                            sadr[11] == dev->dev_addr[3] &&
                                            sadr[12] == dev->dev_addr[4] &&
                                            sadr[13] == dev->dev_addr[5]) {
                                                /* looped-back to us */
                                                goto out;
                                        }
                                }

                                /*
                                 * We are colliding with another node
                                 * who is doing DAD
                                 * so fail our DAD process
                                 */
                                addrconf_dad_failure(ifp);
                                return;
                        } else {
                                /*
                                 * This is not a dad solicitation.
                                 * If we are an optimistic node,
                                 * we should respond.
                                 * Otherwise, we should ignore it.
                                 */
                                if (!(ifp->flags & IFA_F_OPTIMISTIC))
                                        goto out;
                        }
                }

                idev = ifp->idev;
        } else {
                struct net *net = dev_net(dev);

                idev = in6_dev_get(dev);
                if (!idev) {
                        /* XXX: count this drop? */
                        return;
                }

                if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
                    (idev->cnf.forwarding &&
                     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
                     (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
                        if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
                            skb->pkt_type != PACKET_HOST &&
                            inc != 0 &&
                            idev->nd_parms->proxy_delay != 0) {
                                /*
                                 * for anycast or proxy,
                                 * sender should delay its response
                                 * by a random time between 0 and
                                 * MAX_ANYCAST_DELAY_TIME seconds.
                                 * (RFC2461) -- yoshfuji
                                 */
                                struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
                                if (n)
                                        pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
                                goto out;
                        }
                } else
                        goto out;
        }

        if (is_router < 0)
                is_router = !!idev->cnf.forwarding;

        if (dad) {
                ndisc_send_na(dev, NULL, &in6addr_linklocal_allnodes, &msg->target,
                              is_router, 0, (ifp != NULL), 1);
                goto out;
        }

        if (inc)
                NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
        else
                NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);

        /*
         *      update / create cache entry
         *      for the source address
         */
        neigh = __neigh_lookup(&nd_tbl, saddr, dev,
                               !inc || lladdr || !dev->addr_len);
        if (neigh)
                neigh_update(neigh, lladdr, NUD_STALE,
                             NEIGH_UPDATE_F_WEAK_OVERRIDE|
                             NEIGH_UPDATE_F_OVERRIDE);
        if (neigh || !dev->header_ops) {
                ndisc_send_na(dev, neigh, saddr, &msg->target,
                              is_router,
                              1, (ifp != NULL && inc), inc);
                if (neigh)
                        neigh_release(neigh);
        }

out:
        if (ifp)
                in6_ifa_put(ifp);
        else
                in6_dev_put(idev);

        return;
}

static void ndisc_recv_na(struct sk_buff *skb)
{
        struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
        struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
        struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
        u8 *lladdr = NULL;
        u32 ndoptlen = skb->tail - (skb->transport_header +
                                    offsetof(struct nd_msg, opt));
        struct ndisc_options ndopts;
        struct net_device *dev = skb->dev;
        struct inet6_ifaddr *ifp;
        struct neighbour *neigh;

        if (skb->len < sizeof(struct nd_msg)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NA: packet too short\n");
                return;
        }

        if (ipv6_addr_is_multicast(&msg->target)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NA: target address is multicast.\n");
                return;
        }

        if (ipv6_addr_is_multicast(daddr) &&
            msg->icmph.icmp6_solicited) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NA: solicited NA is multicasted.\n");
                return;
        }

        if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NS: invalid ND option\n");
                return;
        }
        if (ndopts.nd_opts_tgt_lladdr) {
                lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
                if (!lladdr) {
                        ND_PRINTK2(KERN_WARNING
                                   "ICMPv6 NA: invalid link-layer address length\n");
                        return;
                }
        }
        ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
        if (ifp) {
                if (ifp->flags & IFA_F_TENTATIVE) {
                        addrconf_dad_failure(ifp);
                        return;
                }
                /* What should we make now? The advertisement
                   is invalid, but ndisc specs say nothing
                   about it. It could be misconfiguration, or
                   an smart proxy agent tries to help us :-)
                 */
                ND_PRINTK1(KERN_WARNING
                           "ICMPv6 NA: someone advertises our address on %s!\n",
                           ifp->idev->dev->name);
                in6_ifa_put(ifp);
                return;
        }
        neigh = neigh_lookup(&nd_tbl, &msg->target, dev);

        if (neigh) {
                u8 old_flags = neigh->flags;
                struct net *net = dev_net(dev);

                if (neigh->nud_state & NUD_FAILED)
                        goto out;

                /*
                 * Don't update the neighbor cache entry on a proxy NA from
                 * ourselves because either the proxied node is off link or it
                 * has already sent a NA to us.
                 */
                if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
                    net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
                    pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
                        /* XXX: idev->cnf.prixy_ndp */
                        goto out;
                }

                neigh_update(neigh, lladdr,
                             msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE,
                             NEIGH_UPDATE_F_WEAK_OVERRIDE|
                             (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
                             NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
                             (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0));

                if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
                        /*
                         * Change: router to host
                         */
                        struct rt6_info *rt;
                        rt = rt6_get_dflt_router(saddr, dev);
                        if (rt)
                                ip6_del_rt(rt);
                }

out:
                neigh_release(neigh);
        }
}

static void ndisc_recv_rs(struct sk_buff *skb)
{
        struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
        unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
        struct neighbour *neigh;
        struct inet6_dev *idev;
        struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
        struct ndisc_options ndopts;
        u8 *lladdr = NULL;

        if (skb->len < sizeof(*rs_msg))
                return;

        idev = in6_dev_get(skb->dev);
        if (!idev) {
                if (net_ratelimit())
                        ND_PRINTK1("ICMP6 RS: can't find in6 device\n");
                return;
        }

        /* Don't accept RS if we're not in router mode */
        if (!idev->cnf.forwarding)
                goto out;

        /*
         * Don't update NCE if src = ::;
         * this implies that the source node has no ip address assigned yet.
         */
        if (ipv6_addr_any(saddr))
                goto out;

        /* Parse ND options */
        if (!ndisc_parse_options(rs_msg->opt, ndoptlen, &ndopts)) {
                if (net_ratelimit())
                        ND_PRINTK2("ICMP6 NS: invalid ND option, ignored\n");
                goto out;
        }

        if (ndopts.nd_opts_src_lladdr) {
                lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
                                             skb->dev);
                if (!lladdr)
                        goto out;
        }

        neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
        if (neigh) {
                neigh_update(neigh, lladdr, NUD_STALE,
                             NEIGH_UPDATE_F_WEAK_OVERRIDE|
                             NEIGH_UPDATE_F_OVERRIDE|
                             NEIGH_UPDATE_F_OVERRIDE_ISROUTER);
                neigh_release(neigh);
        }
out:
        in6_dev_put(idev);
}

static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
{
        struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
        struct sk_buff *skb;
        struct nlmsghdr *nlh;
        struct nduseroptmsg *ndmsg;
        struct net *net = dev_net(ra->dev);
        int err;
        int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
                                    + (opt->nd_opt_len << 3));
        size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));

        skb = nlmsg_new(msg_size, GFP_ATOMIC);
        if (skb == NULL) {
                err = -ENOBUFS;
                goto errout;
        }

        nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
        if (nlh == NULL) {
                goto nla_put_failure;
        }

        ndmsg = nlmsg_data(nlh);
        ndmsg->nduseropt_family = AF_INET6;
        ndmsg->nduseropt_ifindex = ra->dev->ifindex;
        ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
        ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
        ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;

        memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);

        NLA_PUT(skb, NDUSEROPT_SRCADDR, sizeof(struct in6_addr),
                &ipv6_hdr(ra)->saddr);
        nlmsg_end(skb, nlh);

        err = rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL,
                          GFP_ATOMIC);
        if (err < 0)
                goto errout;

        return;

nla_put_failure:
        nlmsg_free(skb);
        err = -EMSGSIZE;
errout:
        rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
}

static void ndisc_router_discovery(struct sk_buff *skb)
{
        struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
        struct neighbour *neigh = NULL;
        struct inet6_dev *in6_dev;
        struct rt6_info *rt = NULL;
        int lifetime;
        struct ndisc_options ndopts;
        int optlen;
        unsigned int pref = 0;

        __u8 * opt = (__u8 *)(ra_msg + 1);

        optlen = (skb->tail - skb->transport_header) - sizeof(struct ra_msg);

        if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 RA: source address is not link-local.\n");
                return;
        }
        if (optlen < 0) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 RA: packet too short\n");
                return;
        }

#ifdef CONFIG_IPV6_NDISC_NODETYPE
        if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 RA: from host or unauthorized router\n");
                return;
        }
#endif

        /*
         *      set the RA_RECV flag in the interface
         */

        in6_dev = in6_dev_get(skb->dev);
        if (in6_dev == NULL) {
                ND_PRINTK0(KERN_ERR
                           "ICMPv6 RA: can't find inet6 device for %s.\n",
                           skb->dev->name);
                return;
        }
        if (in6_dev->cnf.forwarding || !in6_dev->cnf.accept_ra) {
                in6_dev_put(in6_dev);
                return;
        }

        if (!ndisc_parse_options(opt, optlen, &ndopts)) {
                in6_dev_put(in6_dev);
                ND_PRINTK2(KERN_WARNING
                           "ICMP6 RA: invalid ND options\n");
                return;
        }

#ifdef CONFIG_IPV6_NDISC_NODETYPE
        /* skip link-specific parameters from interior routers */
        if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT)
                goto skip_linkparms;
#endif

        if (in6_dev->if_flags & IF_RS_SENT) {
                /*
                 *      flag that an RA was received after an RS was sent
                 *      out on this interface.
                 */
                in6_dev->if_flags |= IF_RA_RCVD;
        }

        /*
         * Remember the managed/otherconf flags from most recently
         * received RA message (RFC 2462) -- yoshfuji
         */
        in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
                                IF_RA_OTHERCONF)) |
                                (ra_msg->icmph.icmp6_addrconf_managed ?
                                        IF_RA_MANAGED : 0) |
                                (ra_msg->icmph.icmp6_addrconf_other ?
                                        IF_RA_OTHERCONF : 0);

        if (!in6_dev->cnf.accept_ra_defrtr)
                goto skip_defrtr;

        lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);

#ifdef CONFIG_IPV6_ROUTER_PREF
        pref = ra_msg->icmph.icmp6_router_pref;
        /* 10b is handled as if it were 00b (medium) */
        if (pref == ICMPV6_ROUTER_PREF_INVALID ||
            !in6_dev->cnf.accept_ra_rtr_pref)
                pref = ICMPV6_ROUTER_PREF_MEDIUM;
#endif

        rt = rt6_get_dflt_router(&ipv6_hdr(skb)->saddr, skb->dev);

        if (rt)
                neigh = rt->rt6i_nexthop;

        if (rt && lifetime == 0) {
                neigh_clone(neigh);
                ip6_del_rt(rt);
                rt = NULL;
        }

        if (rt == NULL && lifetime) {
                ND_PRINTK3(KERN_DEBUG
                           "ICMPv6 RA: adding default router.\n");

                rt = rt6_add_dflt_router(&ipv6_hdr(skb)->saddr, skb->dev, pref);
                if (rt == NULL) {
                        ND_PRINTK0(KERN_ERR
                                   "ICMPv6 RA: %s() failed to add default route.\n",
                                   __func__);
                        in6_dev_put(in6_dev);
                        return;
                }

                neigh = rt->rt6i_nexthop;
                if (neigh == NULL) {
                        ND_PRINTK0(KERN_ERR
                                   "ICMPv6 RA: %s() got default router without neighbour.\n",
                                   __func__);
                        dst_release(&rt->u.dst);
                        in6_dev_put(in6_dev);
                        return;
                }
                neigh->flags |= NTF_ROUTER;
        } else if (rt) {
                rt->rt6i_flags |= (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
        }

        if (rt)
                rt->rt6i_expires = jiffies + (HZ * lifetime);

        if (ra_msg->icmph.icmp6_hop_limit) {
                in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
                if (rt)
                        rt->u.dst.metrics[RTAX_HOPLIMIT-1] = ra_msg->icmph.icmp6_hop_limit;
        }

skip_defrtr:

        /*
         *      Update Reachable Time and Retrans Timer
         */

        if (in6_dev->nd_parms) {
                unsigned long rtime = ntohl(ra_msg->retrans_timer);

                if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
                        rtime = (rtime*HZ)/1000;
                        if (rtime < HZ/10)
                                rtime = HZ/10;
                        in6_dev->nd_parms->retrans_time = rtime;
                        in6_dev->tstamp = jiffies;
                        inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
                }

                rtime = ntohl(ra_msg->reachable_time);
                if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
                        rtime = (rtime*HZ)/1000;

                        if (rtime < HZ/10)
                                rtime = HZ/10;

                        if (rtime != in6_dev->nd_parms->base_reachable_time) {
                                in6_dev->nd_parms->base_reachable_time = rtime;
                                in6_dev->nd_parms->gc_staletime = 3 * rtime;
                                in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
                                in6_dev->tstamp = jiffies;
                                inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
                        }
                }
        }

#ifdef CONFIG_IPV6_NDISC_NODETYPE
skip_linkparms:
#endif

        /*
         *      Process options.
         */

        if (!neigh)
                neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
                                       skb->dev, 1);
        if (neigh) {
                u8 *lladdr = NULL;
                if (ndopts.nd_opts_src_lladdr) {
                        lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
                                                     skb->dev);
                        if (!lladdr) {
                                ND_PRINTK2(KERN_WARNING
                                           "ICMPv6 RA: invalid link-layer address length\n");
                                goto out;
                        }
                }
                neigh_update(neigh, lladdr, NUD_STALE,
                             NEIGH_UPDATE_F_WEAK_OVERRIDE|
                             NEIGH_UPDATE_F_OVERRIDE|
                             NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
                             NEIGH_UPDATE_F_ISROUTER);
        }

#ifdef CONFIG_IPV6_ROUTE_INFO
        if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
                struct nd_opt_hdr *p;
                for (p = ndopts.nd_opts_ri;
                     p;
                     p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
                        struct route_info *ri = (struct route_info *)p;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
                        if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
                            ri->prefix_len == 0)
                                continue;
#endif
                        if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
                                continue;
                        rt6_route_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3,
                                      &ipv6_hdr(skb)->saddr);
                }
        }
#endif

#ifdef CONFIG_IPV6_NDISC_NODETYPE
        /* skip link-specific ndopts from interior routers */
        if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT)
                goto out;
#endif

        if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
                struct nd_opt_hdr *p;
                for (p = ndopts.nd_opts_pi;
                     p;
                     p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
                        addrconf_prefix_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3);
                }
        }

        if (ndopts.nd_opts_mtu) {
                __be32 n;
                u32 mtu;

                memcpy(&n, ((u8*)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
                mtu = ntohl(n);

                if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
                        ND_PRINTK2(KERN_WARNING
                                   "ICMPv6 RA: invalid mtu: %d\n",
                                   mtu);
                } else if (in6_dev->cnf.mtu6 != mtu) {
                        in6_dev->cnf.mtu6 = mtu;

                        if (rt)
                                rt->u.dst.metrics[RTAX_MTU-1] = mtu;

                        rt6_mtu_change(skb->dev, mtu);
                }
        }

        if (ndopts.nd_useropts) {
                struct nd_opt_hdr *p;
                for (p = ndopts.nd_useropts;
                     p;
                     p = ndisc_next_useropt(p, ndopts.nd_useropts_end)) {
                        ndisc_ra_useropt(skb, p);
                }
        }

        if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 RA: invalid RA options");
        }
out:
        if (rt)
                dst_release(&rt->u.dst);
        else if (neigh)
                neigh_release(neigh);
        in6_dev_put(in6_dev);
}

static void ndisc_redirect_rcv(struct sk_buff *skb)
{
        struct inet6_dev *in6_dev;
        struct icmp6hdr *icmph;
        struct in6_addr *dest;
        struct in6_addr *target;        /* new first hop to destination */
        struct neighbour *neigh;
        int on_link = 0;
        struct ndisc_options ndopts;
        int optlen;
        u8 *lladdr = NULL;

#ifdef CONFIG_IPV6_NDISC_NODETYPE
        switch (skb->ndisc_nodetype) {
        case NDISC_NODETYPE_HOST:
        case NDISC_NODETYPE_NODEFAULT:
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: from host or unauthorized router\n");
                return;
        }
#endif

        if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: source address is not link-local.\n");
                return;
        }

        optlen = skb->tail - skb->transport_header;
        optlen -= sizeof(struct icmp6hdr) + 2 * sizeof(struct in6_addr);

        if (optlen < 0) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: packet too short\n");
                return;
        }

        icmph = icmp6_hdr(skb);
        target = (struct in6_addr *) (icmph + 1);
        dest = target + 1;

        if (ipv6_addr_is_multicast(dest)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: destination address is multicast.\n");
                return;
        }

        if (ipv6_addr_equal(dest, target)) {
                on_link = 1;
        } else if (ipv6_addr_type(target) !=
                   (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: target address is not link-local unicast.\n");
                return;
        }

        in6_dev = in6_dev_get(skb->dev);
        if (!in6_dev)
                return;
        if (in6_dev->cnf.forwarding || !in6_dev->cnf.accept_redirects) {
                in6_dev_put(in6_dev);
                return;
        }

        /* RFC2461 8.1:
         *      The IP source address of the Redirect MUST be the same as the current
         *      first-hop router for the specified ICMP Destination Address.
         */

        if (!ndisc_parse_options((u8*)(dest + 1), optlen, &ndopts)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: invalid ND options\n");
                in6_dev_put(in6_dev);
                return;
        }
        if (ndopts.nd_opts_tgt_lladdr) {
                lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr,
                                             skb->dev);
                if (!lladdr) {
                        ND_PRINTK2(KERN_WARNING
                                   "ICMPv6 Redirect: invalid link-layer address length\n");
                        in6_dev_put(in6_dev);
                        return;
                }
        }

        neigh = __neigh_lookup(&nd_tbl, target, skb->dev, 1);
        if (neigh) {
                rt6_redirect(dest, &ipv6_hdr(skb)->daddr,
                             &ipv6_hdr(skb)->saddr, neigh, lladdr,
                             on_link);
                neigh_release(neigh);
        }
        in6_dev_put(in6_dev);
}

void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
                         const struct in6_addr *target)
{
        struct net_device *dev = skb->dev;
        struct net *net = dev_net(dev);
        struct sock *sk = net->ipv6.ndisc_sk;
        int len = sizeof(struct icmp6hdr) + 2 * sizeof(struct in6_addr);
        struct sk_buff *buff;
        struct icmp6hdr *icmph;
        struct in6_addr saddr_buf;
        struct in6_addr *addrp;
        struct rt6_info *rt;
        struct dst_entry *dst;
        struct inet6_dev *idev;
        struct flowi fl;
        u8 *opt;
        int rd_len;
        int err;
        u8 ha_buf[MAX_ADDR_LEN], *ha = NULL;

        if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: no link-local address on %s\n",
                           dev->name);
                return;
        }

        if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
            ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
                ND_PRINTK2(KERN_WARNING
                        "ICMPv6 Redirect: target address is not link-local unicast.\n");
                return;
        }

        icmpv6_flow_init(sk, &fl, NDISC_REDIRECT,
                         &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);

        dst = ip6_route_output(net, NULL, &fl);
        if (dst == NULL)
                return;

        err = xfrm_lookup(&dst, &fl, NULL, 0);
        if (err)
                return;

        rt = (struct rt6_info *) dst;

        if (rt->rt6i_flags & RTF_GATEWAY) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 Redirect: destination is not a neighbour.\n");
                dst_release(dst);
                return;
        }
        if (!xrlim_allow(dst, 1*HZ)) {
                dst_release(dst);
                return;
        }

        if (dev->addr_len) {
                read_lock_bh(&neigh->lock);
                if (neigh->nud_state & NUD_VALID) {
                        memcpy(ha_buf, neigh->ha, dev->addr_len);
                        read_unlock_bh(&neigh->lock);
                        ha = ha_buf;
                        len += ndisc_opt_addr_space(dev);
                } else
                        read_unlock_bh(&neigh->lock);
        }

        rd_len = min_t(unsigned int,
                     IPV6_MIN_MTU-sizeof(struct ipv6hdr)-len, skb->len + 8);
        rd_len &= ~0x7;
        len += rd_len;

        buff = sock_alloc_send_skb(sk,
                                   (MAX_HEADER + sizeof(struct ipv6hdr) +
                                    len + LL_ALLOCATED_SPACE(dev)),
                                   1, &err);
        if (buff == NULL) {
                ND_PRINTK0(KERN_ERR
                           "ICMPv6 Redirect: %s() failed to allocate an skb.\n",
                           __func__);
                dst_release(dst);
                return;
        }

        skb_reserve(buff, LL_RESERVED_SPACE(dev));
        ip6_nd_hdr(sk, buff, dev, &saddr_buf, &ipv6_hdr(skb)->saddr,
                   IPPROTO_ICMPV6, len);

        skb_set_transport_header(buff, skb_tail_pointer(buff) - buff->data);
        skb_put(buff, len);
        icmph = icmp6_hdr(buff);

        memset(icmph, 0, sizeof(struct icmp6hdr));
        icmph->icmp6_type = NDISC_REDIRECT;

        /*
         *      copy target and destination addresses
         */

        addrp = (struct in6_addr *)(icmph + 1);
        ipv6_addr_copy(addrp, target);
        addrp++;
        ipv6_addr_copy(addrp, &ipv6_hdr(skb)->daddr);

        opt = (u8*) (addrp + 1);

        /*
         *      include target_address option
         */

        if (ha)
                opt = ndisc_fill_addr_option(opt, ND_OPT_TARGET_LL_ADDR, ha,
                                             dev->addr_len, dev->type);

        /*
         *      build redirect option and copy skb over to the new packet.
         */

        memset(opt, 0, 8);
        *(opt++) = ND_OPT_REDIRECT_HDR;
        *(opt++) = (rd_len >> 3);
        opt += 6;

        memcpy(opt, ipv6_hdr(skb), rd_len - 8);

        icmph->icmp6_cksum = csum_ipv6_magic(&saddr_buf, &ipv6_hdr(skb)->saddr,
                                             len, IPPROTO_ICMPV6,
                                             csum_partial((u8 *) icmph, len, 0));

        buff->dst = dst;
        idev = in6_dev_get(dst->dev);
        IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
        err = NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, buff, NULL, dst->dev,
                      dst_output);
        if (!err) {
                ICMP6MSGOUT_INC_STATS(net, idev, NDISC_REDIRECT);
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
        }

        if (likely(idev != NULL))
                in6_dev_put(idev);
}

static void pndisc_redo(struct sk_buff *skb)
{
        ndisc_recv_ns(skb);
        kfree_skb(skb);
}

int ndisc_rcv(struct sk_buff *skb)
{
        struct nd_msg *msg;

        if (!pskb_may_pull(skb, skb->len))
                return 0;

        msg = (struct nd_msg *)skb_transport_header(skb);

        __skb_push(skb, skb->data - skb_transport_header(skb));

        if (ipv6_hdr(skb)->hop_limit != 255) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NDISC: invalid hop-limit: %d\n",
                           ipv6_hdr(skb)->hop_limit);
                return 0;
        }

        if (msg->icmph.icmp6_code != 0) {
                ND_PRINTK2(KERN_WARNING
                           "ICMPv6 NDISC: invalid ICMPv6 code: %d\n",
                           msg->icmph.icmp6_code);
                return 0;
        }

        memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));

        switch (msg->icmph.icmp6_type) {
        case NDISC_NEIGHBOUR_SOLICITATION:
                ndisc_recv_ns(skb);
                break;

        case NDISC_NEIGHBOUR_ADVERTISEMENT:
                ndisc_recv_na(skb);
                break;

        case NDISC_ROUTER_SOLICITATION:
                ndisc_recv_rs(skb);
                break;

        case NDISC_ROUTER_ADVERTISEMENT:
                ndisc_router_discovery(skb);
                break;

        case NDISC_REDIRECT:
                ndisc_redirect_rcv(skb);
                break;
        }

        return 0;
}

static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
        struct net_device *dev = ptr;
        struct net *net = dev_net(dev);

        switch (event) {
        case NETDEV_CHANGEADDR:
                neigh_changeaddr(&nd_tbl, dev);
                fib6_run_gc(~0UL, net);
                break;
        case NETDEV_DOWN:
                neigh_ifdown(&nd_tbl, dev);
                fib6_run_gc(~0UL, net);
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

static struct notifier_block ndisc_netdev_notifier = {
        .notifier_call = ndisc_netdev_event,
};

#ifdef CONFIG_SYSCTL
static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
                                         const char *func, const char *dev_name)
{
        static char warncomm[TASK_COMM_LEN];
        static int warned;
        if (strcmp(warncomm, current->comm) && warned < 5) {
                strcpy(warncomm, current->comm);
                printk(KERN_WARNING
                        "process `%s' is using deprecated sysctl (%s) "
                        "net.ipv6.neigh.%s.%s; "
                        "Use net.ipv6.neigh.%s.%s_ms "
                        "instead.\n",
                        warncomm, func,
                        dev_name, ctl->procname,
                        dev_name, ctl->procname);
                warned++;
        }
}

int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, struct file * filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{
        struct net_device *dev = ctl->extra1;
        struct inet6_dev *idev;
        int ret;

        if ((strcmp(ctl->procname, "retrans_time") == 0) ||
            (strcmp(ctl->procname, "base_reachable_time") == 0))
                ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");

        if (strcmp(ctl->procname, "retrans_time") == 0)
                ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);

        else if (strcmp(ctl->procname, "base_reachable_time") == 0)
                ret = proc_dointvec_jiffies(ctl, write,
                                            filp, buffer, lenp, ppos);

        else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
                 (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
                ret = proc_dointvec_ms_jiffies(ctl, write,
                                               filp, buffer, lenp, ppos);
        else
                ret = -1;

        if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
                if (ctl->data == &idev->nd_parms->base_reachable_time)
                        idev->nd_parms->reachable_time = neigh_rand_reach_time(idev->nd_parms->base_reachable_time);
                idev->tstamp = jiffies;
                inet6_ifinfo_notify(RTM_NEWLINK, idev);
                in6_dev_put(idev);
        }
        return ret;
}

int ndisc_ifinfo_sysctl_strategy(ctl_table *ctl, int __user *name,
                                 int nlen, void __user *oldval,
                                 size_t __user *oldlenp,
                                 void __user *newval, size_t newlen)
{
        struct net_device *dev = ctl->extra1;
        struct inet6_dev *idev;
        int ret;

        if (ctl->ctl_name == NET_NEIGH_RETRANS_TIME ||
            ctl->ctl_name == NET_NEIGH_REACHABLE_TIME)
                ndisc_warn_deprecated_sysctl(ctl, "procfs", dev ? dev->name : "default");

        switch (ctl->ctl_name) {
        case NET_NEIGH_REACHABLE_TIME:
                ret = sysctl_jiffies(ctl, name, nlen,
                                     oldval, oldlenp, newval, newlen);
                break;
        case NET_NEIGH_RETRANS_TIME_MS:
        case NET_NEIGH_REACHABLE_TIME_MS:
                 ret = sysctl_ms_jiffies(ctl, name, nlen,
                                         oldval, oldlenp, newval, newlen);
                 break;
        default:
                ret = 0;
        }

        if (newval && newlen && ret > 0 &&
            dev && (idev = in6_dev_get(dev)) != NULL) {
                if (ctl->ctl_name == NET_NEIGH_REACHABLE_TIME ||
                    ctl->ctl_name == NET_NEIGH_REACHABLE_TIME_MS)
                        idev->nd_parms->reachable_time = neigh_rand_reach_time(idev->nd_parms->base_reachable_time);
                idev->tstamp = jiffies;
                inet6_ifinfo_notify(RTM_NEWLINK, idev);
                in6_dev_put(idev);
        }

        return ret;
}

#endif

static int ndisc_net_init(struct net *net)
{
        struct ipv6_pinfo *np;
        struct sock *sk;
        int err;

        err = inet_ctl_sock_create(&sk, PF_INET6,
                                   SOCK_RAW, IPPROTO_ICMPV6, net);
        if (err < 0) {
                ND_PRINTK0(KERN_ERR
                           "ICMPv6 NDISC: Failed to initialize the control socket (err %d).\n",
                           err);
                return err;
        }

        net->ipv6.ndisc_sk = sk;

        np = inet6_sk(sk);
        np->hop_limit = 255;
        /* Do not loopback ndisc messages */
        np->mc_loop = 0;

        return 0;
}

static void ndisc_net_exit(struct net *net)
{
        inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
}

static struct pernet_operations ndisc_net_ops = {
        .init = ndisc_net_init,
        .exit = ndisc_net_exit,
};

int __init ndisc_init(void)
{
        int err;

        err = register_pernet_subsys(&ndisc_net_ops);
        if (err)
                return err;
        /*
         * Initialize the neighbour table
         */
        neigh_table_init(&nd_tbl);

#ifdef CONFIG_SYSCTL
        err = neigh_sysctl_register(NULL, &nd_tbl.parms, NET_IPV6,
                                    NET_IPV6_NEIGH, "ipv6",
                                    &ndisc_ifinfo_sysctl_change,
                                    &ndisc_ifinfo_sysctl_strategy);
        if (err)
                goto out_unregister_pernet;
#endif
        err = register_netdevice_notifier(&ndisc_netdev_notifier);
        if (err)
                goto out_unregister_sysctl;
out:
        return err;

out_unregister_sysctl:
#ifdef CONFIG_SYSCTL
        neigh_sysctl_unregister(&nd_tbl.parms);
out_unregister_pernet:
#endif
        unregister_pernet_subsys(&ndisc_net_ops);
        goto out;
}

void ndisc_cleanup(void)
{
        unregister_netdevice_notifier(&ndisc_netdev_notifier);
#ifdef CONFIG_SYSCTL
        neigh_sysctl_unregister(&nd_tbl.parms);
#endif
        neigh_table_clear(&nd_tbl);
        unregister_pernet_subsys(&ndisc_net_ops);
}

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