net/ipv6/ndisc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Neighbour Discovery for IPv6
   4  *      Linux INET6 implementation
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <[email protected]>
   8  *      Mike Shaver             <[email protected]>
   9  */
  10
  11 /*
  12  *      Changes:
  13  *
  14  *      Alexey I. Froloff               :       RFC6106 (DNSSL) support
  15  *      Pierre Ynard                    :       export userland ND options
  16  *                                              through netlink (RDNSS support)
  17  *      Lars Fenneberg                  :       fixed MTU setting on receipt
  18  *                                              of an RA.
  19  *      Janos Farkas                    :       kmalloc failure checks
  20  *      Alexey Kuznetsov                :       state machine reworked
  21  *                                              and moved to net/core.
  22  *      Pekka Savola                    :       RFC2461 validation
  23  *      YOSHIFUJI Hideaki @USAGI        :       Verify ND options properly
  24  */
  25
  26 #define pr_fmt(fmt) "ICMPv6: " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/types.h>
  31 #include <linux/socket.h>
  32 #include <linux/sockios.h>
  33 #include <linux/sched.h>
  34 #include <linux/net.h>
  35 #include <linux/in6.h>
  36 #include <linux/route.h>
  37 #include <linux/init.h>
  38 #include <linux/rcupdate.h>
  39 #include <linux/slab.h>
  40 #ifdef CONFIG_SYSCTL
  41 #include <linux/sysctl.h>
  42 #endif
  43
  44 #include <linux/if_addr.h>
  45 #include <linux/if_ether.h>
  46 #include <linux/if_arp.h>
  47 #include <linux/ipv6.h>
  48 #include <linux/icmpv6.h>
  49 #include <linux/jhash.h>
  50
  51 #include <net/sock.h>
  52 #include <net/snmp.h>
  53
  54 #include <net/ipv6.h>
  55 #include <net/protocol.h>
  56 #include <net/ndisc.h>
  57 #include <net/ip6_route.h>
  58 #include <net/addrconf.h>
  59 #include <net/icmp.h>
  60
  61 #include <net/netlink.h>
  62 #include <linux/rtnetlink.h>
  63
  64 #include <net/flow.h>
  65 #include <net/ip6_checksum.h>
  66 #include <net/inet_common.h>
  67 #include <linux/proc_fs.h>
  68
  69 #include <linux/netfilter.h>
  70 #include <linux/netfilter_ipv6.h>
  71
  72 static u32 ndisc_hash(const void *pkey,
  73                       const struct net_device *dev,
  74                       __u32 *hash_rnd);
  75 static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey);
  76 static bool ndisc_allow_add(const struct net_device *dev,
  77                             struct netlink_ext_ack *extack);
  78 static int ndisc_constructor(struct neighbour *neigh);
  79 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
  80 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
  81 static int pndisc_constructor(struct pneigh_entry *n);
  82 static void pndisc_destructor(struct pneigh_entry *n);
  83 static void pndisc_redo(struct sk_buff *skb);
  84 static int ndisc_is_multicast(const void *pkey);
  85
  86 static const struct neigh_ops ndisc_generic_ops = {
  87         .family =               AF_INET6,
  88         .solicit =              ndisc_solicit,
  89         .error_report =         ndisc_error_report,
  90         .output =               neigh_resolve_output,
  91         .connected_output =     neigh_connected_output,
  92 };
  93
  94 static const struct neigh_ops ndisc_hh_ops = {
  95         .family =               AF_INET6,
  96         .solicit =              ndisc_solicit,
  97         .error_report =         ndisc_error_report,
  98         .output =               neigh_resolve_output,
  99         .connected_output =     neigh_resolve_output,
 100 };
 101
 102
 103 static const struct neigh_ops ndisc_direct_ops = {
 104         .family =               AF_INET6,
 105         .output =               neigh_direct_output,
 106         .connected_output =     neigh_direct_output,
 107 };
 108
 109 struct neigh_table nd_tbl = {
 110         .family =       AF_INET6,
 111         .key_len =      sizeof(struct in6_addr),
 112         .protocol =     cpu_to_be16(ETH_P_IPV6),
 113         .hash =         ndisc_hash,
 114         .key_eq =       ndisc_key_eq,
 115         .constructor =  ndisc_constructor,
 116         .pconstructor = pndisc_constructor,
 117         .pdestructor =  pndisc_destructor,
 118         .proxy_redo =   pndisc_redo,
 119         .is_multicast = ndisc_is_multicast,
 120         .allow_add  =   ndisc_allow_add,
 121         .id =           "ndisc_cache",
 122         .parms = {
 123                 .tbl                    = &nd_tbl,
 124                 .reachable_time         = ND_REACHABLE_TIME,
 125                 .data = {
 126                         [NEIGH_VAR_MCAST_PROBES] = 3,
 127                         [NEIGH_VAR_UCAST_PROBES] = 3,
 128                         [NEIGH_VAR_RETRANS_TIME] = ND_RETRANS_TIMER,
 129                         [NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,
 130                         [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
 131                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 132                         [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
 133                         [NEIGH_VAR_PROXY_QLEN] = 64,
 134                         [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
 135                         [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
 136                 },
 137         },
 138         .gc_interval =    30 * HZ,
 139         .gc_thresh1 =    128,
 140         .gc_thresh2 =    512,
 141         .gc_thresh3 =   1024,
 142 };
 143 EXPORT_SYMBOL_GPL(nd_tbl);
 144
 145 void __ndisc_fill_addr_option(struct sk_buff *skb, int type, const void *data,
 146                               int data_len, int pad)
 147 {
 148         int space = __ndisc_opt_addr_space(data_len, pad);
 149         u8 *opt = skb_put(skb, space);
 150
 151         opt[0] = type;
 152         opt[1] = space>>3;
 153
 154         memset(opt + 2, 0, pad);
 155         opt   += pad;
 156         space -= pad;
 157
 158         memcpy(opt+2, data, data_len);
 159         data_len += 2;
 160         opt += data_len;
 161         space -= data_len;
 162         if (space > 0)
 163                 memset(opt, 0, space);
 164 }
 165 EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option);
 166
 167 static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type,
 168                                           const void *data, u8 icmp6_type)
 169 {
 170         __ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len,
 171                                  ndisc_addr_option_pad(skb->dev->type));
 172         ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type);
 173 }
 174
 175 static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb,
 176                                                    void *ha,
 177                                                    const u8 *ops_data)
 178 {
 179         ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT);
 180         ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data);
 181 }
 182
 183 static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
 184                                             struct nd_opt_hdr *end)
 185 {
 186         int type;
 187         if (!cur || !end || cur >= end)
 188                 return NULL;
 189         type = cur->nd_opt_type;
 190         do {
 191                 cur = ((void *)cur) + (cur->nd_opt_len << 3);
 192         } while (cur < end && cur->nd_opt_type != type);
 193         return cur <= end && cur->nd_opt_type == type ? cur : NULL;
 194 }
 195
 196 static inline int ndisc_is_useropt(const struct net_device *dev,
 197                                    struct nd_opt_hdr *opt)
 198 {
 199         return opt->nd_opt_type == ND_OPT_RDNSS ||
 200                 opt->nd_opt_type == ND_OPT_DNSSL ||
 201                 opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
 202                 opt->nd_opt_type == ND_OPT_PREF64 ||
 203                 ndisc_ops_is_useropt(dev, opt->nd_opt_type);
 204 }
 205
 206 static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
 207                                              struct nd_opt_hdr *cur,
 208                                              struct nd_opt_hdr *end)
 209 {
 210         if (!cur || !end || cur >= end)
 211                 return NULL;
 212         do {
 213                 cur = ((void *)cur) + (cur->nd_opt_len << 3);
 214         } while (cur < end && !ndisc_is_useropt(dev, cur));
 215         return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
 216 }
 217
 218 struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
 219                                           u8 *opt, int opt_len,
 220                                           struct ndisc_options *ndopts)
 221 {
 222         struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
 223
 224         if (!nd_opt || opt_len < 0 || !ndopts)
 225                 return NULL;
 226         memset(ndopts, 0, sizeof(*ndopts));
 227         while (opt_len) {
 228                 int l;
 229                 if (opt_len < sizeof(struct nd_opt_hdr))
 230                         return NULL;
 231                 l = nd_opt->nd_opt_len << 3;
 232                 if (opt_len < l || l == 0)
 233                         return NULL;
 234                 if (ndisc_ops_parse_options(dev, nd_opt, ndopts))
 235                         goto next_opt;
 236                 switch (nd_opt->nd_opt_type) {
 237                 case ND_OPT_SOURCE_LL_ADDR:
 238                 case ND_OPT_TARGET_LL_ADDR:
 239                 case ND_OPT_MTU:
 240                 case ND_OPT_NONCE:
 241                 case ND_OPT_REDIRECT_HDR:
 242                         if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
 243                                 ND_PRINTK(2, warn,
 244                                           "%s: duplicated ND6 option found: type=%d\n",
 245                                           __func__, nd_opt->nd_opt_type);
 246                         } else {
 247                                 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
 248                         }
 249                         break;
 250                 case ND_OPT_PREFIX_INFO:
 251                         ndopts->nd_opts_pi_end = nd_opt;
 252                         if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
 253                                 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
 254                         break;
 255 #ifdef CONFIG_IPV6_ROUTE_INFO
 256                 case ND_OPT_ROUTE_INFO:
 257                         ndopts->nd_opts_ri_end = nd_opt;
 258                         if (!ndopts->nd_opts_ri)
 259                                 ndopts->nd_opts_ri = nd_opt;
 260                         break;
 261 #endif
 262                 default:
 263                         if (ndisc_is_useropt(dev, nd_opt)) {
 264                                 ndopts->nd_useropts_end = nd_opt;
 265                                 if (!ndopts->nd_useropts)
 266                                         ndopts->nd_useropts = nd_opt;
 267                         } else {
 268                                 /*
 269                                  * Unknown options must be silently ignored,
 270                                  * to accommodate future extension to the
 271                                  * protocol.
 272                                  */
 273                                 ND_PRINTK(2, notice,
 274                                           "%s: ignored unsupported option; type=%d, len=%d\n",
 275                                           __func__,
 276                                           nd_opt->nd_opt_type,
 277                                           nd_opt->nd_opt_len);
 278                         }
 279                 }
 280 next_opt:
 281                 opt_len -= l;
 282                 nd_opt = ((void *)nd_opt) + l;
 283         }
 284         return ndopts;
 285 }
 286
 287 int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
 288 {
 289         switch (dev->type) {
 290         case ARPHRD_ETHER:
 291         case ARPHRD_IEEE802:    /* Not sure. Check it later. --ANK */
 292         case ARPHRD_FDDI:
 293                 ipv6_eth_mc_map(addr, buf);
 294                 return 0;
 295         case ARPHRD_ARCNET:
 296                 ipv6_arcnet_mc_map(addr, buf);
 297                 return 0;
 298         case ARPHRD_INFINIBAND:
 299                 ipv6_ib_mc_map(addr, dev->broadcast, buf);
 300                 return 0;
 301         case ARPHRD_IPGRE:
 302                 return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
 303         default:
 304                 if (dir) {
 305                         memcpy(buf, dev->broadcast, dev->addr_len);
 306                         return 0;
 307                 }
 308         }
 309         return -EINVAL;
 310 }
 311 EXPORT_SYMBOL(ndisc_mc_map);
 312
 313 static u32 ndisc_hash(const void *pkey,
 314                       const struct net_device *dev,
 315                       __u32 *hash_rnd)
 316 {
 317         return ndisc_hashfn(pkey, dev, hash_rnd);
 318 }
 319
 320 static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
 321 {
 322         return neigh_key_eq128(n, pkey);
 323 }
 324
 325 static int ndisc_constructor(struct neighbour *neigh)
 326 {
 327         struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;
 328         struct net_device *dev = neigh->dev;
 329         struct inet6_dev *in6_dev;
 330         struct neigh_parms *parms;
 331         bool is_multicast = ipv6_addr_is_multicast(addr);
 332
 333         in6_dev = in6_dev_get(dev);
 334         if (!in6_dev) {
 335                 return -EINVAL;
 336         }
 337
 338         parms = in6_dev->nd_parms;
 339         __neigh_parms_put(neigh->parms);
 340         neigh->parms = neigh_parms_clone(parms);
 341
 342         neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
 343         if (!dev->header_ops) {
 344                 neigh->nud_state = NUD_NOARP;
 345                 neigh->ops = &ndisc_direct_ops;
 346                 neigh->output = neigh_direct_output;
 347         } else {
 348                 if (is_multicast) {
 349                         neigh->nud_state = NUD_NOARP;
 350                         ndisc_mc_map(addr, neigh->ha, dev, 1);
 351                 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
 352                         neigh->nud_state = NUD_NOARP;
 353                         memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
 354                         if (dev->flags&IFF_LOOPBACK)
 355                                 neigh->type = RTN_LOCAL;
 356                 } else if (dev->flags&IFF_POINTOPOINT) {
 357                         neigh->nud_state = NUD_NOARP;
 358                         memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 359                 }
 360                 if (dev->header_ops->cache)
 361                         neigh->ops = &ndisc_hh_ops;
 362                 else
 363                         neigh->ops = &ndisc_generic_ops;
 364                 if (neigh->nud_state&NUD_VALID)
 365                         neigh->output = neigh->ops->connected_output;
 366                 else
 367                         neigh->output = neigh->ops->output;
 368         }
 369         in6_dev_put(in6_dev);
 370         return 0;
 371 }
 372
 373 static int pndisc_constructor(struct pneigh_entry *n)
 374 {
 375         struct in6_addr *addr = (struct in6_addr *)&n->key;
 376         struct in6_addr maddr;
 377         struct net_device *dev = n->dev;
 378
 379         if (!dev || !__in6_dev_get(dev))
 380                 return -EINVAL;
 381         addrconf_addr_solict_mult(addr, &maddr);
 382         ipv6_dev_mc_inc(dev, &maddr);
 383         return 0;
 384 }
 385
 386 static void pndisc_destructor(struct pneigh_entry *n)
 387 {
 388         struct in6_addr *addr = (struct in6_addr *)&n->key;
 389         struct in6_addr maddr;
 390         struct net_device *dev = n->dev;
 391
 392         if (!dev || !__in6_dev_get(dev))
 393                 return;
 394         addrconf_addr_solict_mult(addr, &maddr);
 395         ipv6_dev_mc_dec(dev, &maddr);
 396 }
 397
 398 /* called with rtnl held */
 399 static bool ndisc_allow_add(const struct net_device *dev,
 400                             struct netlink_ext_ack *extack)
 401 {
 402         struct inet6_dev *idev = __in6_dev_get(dev);
 403
 404         if (!idev || idev->cnf.disable_ipv6) {
 405                 NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
 406                 return false;
 407         }
 408
 409         return true;
 410 }
 411
 412 static struct sk_buff *ndisc_alloc_skb(struct net_device *dev,
 413                                        int len)
 414 {
 415         int hlen = LL_RESERVED_SPACE(dev);
 416         int tlen = dev->needed_tailroom;
 417         struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
 418         struct sk_buff *skb;
 419
 420         skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
 421         if (!skb) {
 422                 ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
 423                           __func__);
 424                 return NULL;
 425         }
 426
 427         skb->protocol = htons(ETH_P_IPV6);
 428         skb->dev = dev;
 429
 430         skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
 431         skb_reset_transport_header(skb);
 432
 433         /* Manually assign socket ownership as we avoid calling
 434          * sock_alloc_send_pskb() to bypass wmem buffer limits
 435          */
 436         skb_set_owner_w(skb, sk);
 437
 438         return skb;
 439 }
 440
 441 static void ip6_nd_hdr(struct sk_buff *skb,
 442                        const struct in6_addr *saddr,
 443                        const struct in6_addr *daddr,
 444                        int hop_limit, int len)
 445 {
 446         struct ipv6hdr *hdr;
 447         struct inet6_dev *idev;
 448         unsigned tclass;
 449
 450         rcu_read_lock();
 451         idev = __in6_dev_get(skb->dev);
 452         tclass = idev ? idev->cnf.ndisc_tclass : 0;
 453         rcu_read_unlock();
 454
 455         skb_push(skb, sizeof(*hdr));
 456         skb_reset_network_header(skb);
 457         hdr = ipv6_hdr(skb);
 458
 459         ip6_flow_hdr(hdr, tclass, 0);
 460
 461         hdr->payload_len = htons(len);
 462         hdr->nexthdr = IPPROTO_ICMPV6;
 463         hdr->hop_limit = hop_limit;
 464
 465         hdr->saddr = *saddr;
 466         hdr->daddr = *daddr;
 467 }
 468
 469 void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr,
 470                     const struct in6_addr *saddr)
 471 {
 472         struct dst_entry *dst = skb_dst(skb);
 473         struct net *net = dev_net(skb->dev);
 474         struct sock *sk = net->ipv6.ndisc_sk;
 475         struct inet6_dev *idev;
 476         int err;
 477         struct icmp6hdr *icmp6h = icmp6_hdr(skb);
 478         u8 type;
 479
 480         type = icmp6h->icmp6_type;
 481
 482         if (!dst) {
 483                 struct flowi6 fl6;
 484                 int oif = skb->dev->ifindex;
 485
 486                 icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif);
 487                 dst = icmp6_dst_alloc(skb->dev, &fl6);
 488                 if (IS_ERR(dst)) {
 489                         kfree_skb(skb);
 490                         return;
 491                 }
 492
 493                 skb_dst_set(skb, dst);
 494         }
 495
 496         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len,
 497                                               IPPROTO_ICMPV6,
 498                                               csum_partial(icmp6h,
 499                                                            skb->len, 0));
 500
 501         ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len);
 502
 503         rcu_read_lock();
 504         idev = __in6_dev_get(dst->dev);
 505         IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 506
 507         err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 508                       net, sk, skb, NULL, dst->dev,
 509                       dst_output);
 510         if (!err) {
 511                 ICMP6MSGOUT_INC_STATS(net, idev, type);
 512                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
 513         }
 514
 515         rcu_read_unlock();
 516 }
 517 EXPORT_SYMBOL(ndisc_send_skb);
 518
 519 void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
 520                    const struct in6_addr *solicited_addr,
 521                    bool router, bool solicited, bool override, bool inc_opt)
 522 {
 523         struct sk_buff *skb;
 524         struct in6_addr tmpaddr;
 525         struct inet6_ifaddr *ifp;
 526         const struct in6_addr *src_addr;
 527         struct nd_msg *msg;
 528         int optlen = 0;
 529
 530         /* for anycast or proxy, solicited_addr != src_addr */
 531         ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
 532         if (ifp) {
 533                 src_addr = solicited_addr;
 534                 if (ifp->flags & IFA_F_OPTIMISTIC)
 535                         override = false;
 536                 inc_opt |= ifp->idev->cnf.force_tllao;
 537                 in6_ifa_put(ifp);
 538         } else {
 539                 if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
 540                                        inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
 541                                        &tmpaddr))
 542                         return;
 543                 src_addr = &tmpaddr;
 544         }
 545
 546         if (!dev->addr_len)
 547                 inc_opt = false;
 548         if (inc_opt)
 549                 optlen += ndisc_opt_addr_space(dev,
 550                                                NDISC_NEIGHBOUR_ADVERTISEMENT);
 551
 552         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 553         if (!skb)
 554                 return;
 555
 556         msg = skb_put(skb, sizeof(*msg));
 557         *msg = (struct nd_msg) {
 558                 .icmph = {
 559                         .icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
 560                         .icmp6_router = router,
 561                         .icmp6_solicited = solicited,
 562                         .icmp6_override = override,
 563                 },
 564                 .target = *solicited_addr,
 565         };
 566
 567         if (inc_opt)
 568                 ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
 569                                        dev->dev_addr,
 570                                        NDISC_NEIGHBOUR_ADVERTISEMENT);
 571
 572         ndisc_send_skb(skb, daddr, src_addr);
 573 }
 574
 575 static void ndisc_send_unsol_na(struct net_device *dev)
 576 {
 577         struct inet6_dev *idev;
 578         struct inet6_ifaddr *ifa;
 579
 580         idev = in6_dev_get(dev);
 581         if (!idev)
 582                 return;
 583
 584         read_lock_bh(&idev->lock);
 585         list_for_each_entry(ifa, &idev->addr_list, if_list) {
 586                 /* skip tentative addresses until dad completes */
 587                 if (ifa->flags & IFA_F_TENTATIVE &&
 588                     !(ifa->flags & IFA_F_OPTIMISTIC))
 589                         continue;
 590
 591                 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
 592                               /*router=*/ !!idev->cnf.forwarding,
 593                               /*solicited=*/ false, /*override=*/ true,
 594                               /*inc_opt=*/ true);
 595         }
 596         read_unlock_bh(&idev->lock);
 597
 598         in6_dev_put(idev);
 599 }
 600
 601 struct sk_buff *ndisc_ns_create(struct net_device *dev, const struct in6_addr *solicit,
 602                                 const struct in6_addr *saddr, u64 nonce)
 603 {
 604         int inc_opt = dev->addr_len;
 605         struct sk_buff *skb;
 606         struct nd_msg *msg;
 607         int optlen = 0;
 608
 609         if (!saddr)
 610                 return NULL;
 611
 612         if (ipv6_addr_any(saddr))
 613                 inc_opt = false;
 614         if (inc_opt)
 615                 optlen += ndisc_opt_addr_space(dev,
 616                                                NDISC_NEIGHBOUR_SOLICITATION);
 617         if (nonce != 0)
 618                 optlen += 8;
 619
 620         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 621         if (!skb)
 622                 return NULL;
 623
 624         msg = skb_put(skb, sizeof(*msg));
 625         *msg = (struct nd_msg) {
 626                 .icmph = {
 627                         .icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
 628                 },
 629                 .target = *solicit,
 630         };
 631
 632         if (inc_opt)
 633                 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
 634                                        dev->dev_addr,
 635                                        NDISC_NEIGHBOUR_SOLICITATION);
 636         if (nonce != 0) {
 637                 u8 *opt = skb_put(skb, 8);
 638
 639                 opt[0] = ND_OPT_NONCE;
 640                 opt[1] = 8 >> 3;
 641                 memcpy(opt + 2, &nonce, 6);
 642         }
 643
 644         return skb;
 645 }
 646 EXPORT_SYMBOL(ndisc_ns_create);
 647
 648 void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
 649                    const struct in6_addr *daddr, const struct in6_addr *saddr,
 650                    u64 nonce)
 651 {
 652         struct in6_addr addr_buf;
 653         struct sk_buff *skb;
 654
 655         if (!saddr) {
 656                 if (ipv6_get_lladdr(dev, &addr_buf,
 657                                     (IFA_F_TENTATIVE | IFA_F_OPTIMISTIC)))
 658                         return;
 659                 saddr = &addr_buf;
 660         }
 661
 662         skb = ndisc_ns_create(dev, solicit, saddr, nonce);
 663
 664         if (skb)
 665                 ndisc_send_skb(skb, daddr, saddr);
 666 }
 667
 668 void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
 669                    const struct in6_addr *daddr)
 670 {
 671         struct sk_buff *skb;
 672         struct rs_msg *msg;
 673         int send_sllao = dev->addr_len;
 674         int optlen = 0;
 675
 676 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 677         /*
 678          * According to section 2.2 of RFC 4429, we must not
 679          * send router solicitations with a sllao from
 680          * optimistic addresses, but we may send the solicitation
 681          * if we don't include the sllao.  So here we check
 682          * if our address is optimistic, and if so, we
 683          * suppress the inclusion of the sllao.
 684          */
 685         if (send_sllao) {
 686                 struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
 687                                                            dev, 1);
 688                 if (ifp) {
 689                         if (ifp->flags & IFA_F_OPTIMISTIC)  {
 690                                 send_sllao = 0;
 691                         }
 692                         in6_ifa_put(ifp);
 693                 } else {
 694                         send_sllao = 0;
 695                 }
 696         }
 697 #endif
 698         if (send_sllao)
 699                 optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION);
 700
 701         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 702         if (!skb)
 703                 return;
 704
 705         msg = skb_put(skb, sizeof(*msg));
 706         *msg = (struct rs_msg) {
 707                 .icmph = {
 708                         .icmp6_type = NDISC_ROUTER_SOLICITATION,
 709                 },
 710         };
 711
 712         if (send_sllao)
 713                 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
 714                                        dev->dev_addr,
 715                                        NDISC_ROUTER_SOLICITATION);
 716
 717         ndisc_send_skb(skb, daddr, saddr);
 718 }
 719
 720
 721 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
 722 {
 723         /*
 724          *      "The sender MUST return an ICMP
 725          *       destination unreachable"
 726          */
 727         dst_link_failure(skb);
 728         kfree_skb(skb);
 729 }
 730
 731 /* Called with locked neigh: either read or both */
 732
 733 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
 734 {
 735         struct in6_addr *saddr = NULL;
 736         struct in6_addr mcaddr;
 737         struct net_device *dev = neigh->dev;
 738         struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
 739         int probes = atomic_read(&neigh->probes);
 740
 741         if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr,
 742                                            dev, false, 1,
 743                                            IFA_F_TENTATIVE|IFA_F_OPTIMISTIC))
 744                 saddr = &ipv6_hdr(skb)->saddr;
 745         probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
 746         if (probes < 0) {
 747                 if (!(neigh->nud_state & NUD_VALID)) {
 748                         ND_PRINTK(1, dbg,
 749                                   "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
 750                                   __func__, target);
 751                 }
 752                 ndisc_send_ns(dev, target, target, saddr, 0);
 753         } else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) {
 754                 neigh_app_ns(neigh);
 755         } else {
 756                 addrconf_addr_solict_mult(target, &mcaddr);
 757                 ndisc_send_ns(dev, target, &mcaddr, saddr, 0);
 758         }
 759 }
 760
 761 static int pndisc_is_router(const void *pkey,
 762                             struct net_device *dev)
 763 {
 764         struct pneigh_entry *n;
 765         int ret = -1;
 766
 767         read_lock_bh(&nd_tbl.lock);
 768         n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
 769         if (n)
 770                 ret = !!(n->flags & NTF_ROUTER);
 771         read_unlock_bh(&nd_tbl.lock);
 772
 773         return ret;
 774 }
 775
 776 void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
 777                   const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
 778                   struct ndisc_options *ndopts)
 779 {
 780         neigh_update(neigh, lladdr, new, flags, 0);
 781         /* report ndisc ops about neighbour update */
 782         ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
 783 }
 784
 785 static void ndisc_recv_ns(struct sk_buff *skb)
 786 {
 787         struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
 788         const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
 789         const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
 790         u8 *lladdr = NULL;
 791         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 792                                     offsetof(struct nd_msg, opt));
 793         struct ndisc_options ndopts;
 794         struct net_device *dev = skb->dev;
 795         struct inet6_ifaddr *ifp;
 796         struct inet6_dev *idev = NULL;
 797         struct neighbour *neigh;
 798         int dad = ipv6_addr_any(saddr);
 799         bool inc;
 800         int is_router = -1;
 801         u64 nonce = 0;
 802
 803         if (skb->len < sizeof(struct nd_msg)) {
 804                 ND_PRINTK(2, warn, "NS: packet too short\n");
 805                 return;
 806         }
 807
 808         if (ipv6_addr_is_multicast(&msg->target)) {
 809                 ND_PRINTK(2, warn, "NS: multicast target address\n");
 810                 return;
 811         }
 812
 813         /*
 814          * RFC2461 7.1.1:
 815          * DAD has to be destined for solicited node multicast address.
 816          */
 817         if (dad && !ipv6_addr_is_solict_mult(daddr)) {
 818                 ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
 819                 return;
 820         }
 821
 822         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
 823                 ND_PRINTK(2, warn, "NS: invalid ND options\n");
 824                 return;
 825         }
 826
 827         if (ndopts.nd_opts_src_lladdr) {
 828                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
 829                 if (!lladdr) {
 830                         ND_PRINTK(2, warn,
 831                                   "NS: invalid link-layer address length\n");
 832                         return;
 833                 }
 834
 835                 /* RFC2461 7.1.1:
 836                  *      If the IP source address is the unspecified address,
 837                  *      there MUST NOT be source link-layer address option
 838                  *      in the message.
 839                  */
 840                 if (dad) {
 841                         ND_PRINTK(2, warn,
 842                                   "NS: bad DAD packet (link-layer address option)\n");
 843                         return;
 844                 }
 845         }
 846         if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
 847                 memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
 848
 849         inc = ipv6_addr_is_multicast(daddr);
 850
 851         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
 852         if (ifp) {
 853 have_ifp:
 854                 if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
 855                         if (dad) {
 856                                 if (nonce != 0 && ifp->dad_nonce == nonce) {
 857                                         u8 *np = (u8 *)&nonce;
 858                                         /* Matching nonce if looped back */
 859                                         ND_PRINTK(2, notice,
 860                                                   "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
 861                                                   ifp->idev->dev->name,
 862                                                   &ifp->addr, np);
 863                                         goto out;
 864                                 }
 865                                 /*
 866                                  * We are colliding with another node
 867                                  * who is doing DAD
 868                                  * so fail our DAD process
 869                                  */
 870                                 addrconf_dad_failure(skb, ifp);
 871                                 return;
 872                         } else {
 873                                 /*
 874                                  * This is not a dad solicitation.
 875                                  * If we are an optimistic node,
 876                                  * we should respond.
 877                                  * Otherwise, we should ignore it.
 878                                  */
 879                                 if (!(ifp->flags & IFA_F_OPTIMISTIC))
 880                                         goto out;
 881                         }
 882                 }
 883
 884                 idev = ifp->idev;
 885         } else {
 886                 struct net *net = dev_net(dev);
 887
 888                 /* perhaps an address on the master device */
 889                 if (netif_is_l3_slave(dev)) {
 890                         struct net_device *mdev;
 891
 892                         mdev = netdev_master_upper_dev_get_rcu(dev);
 893                         if (mdev) {
 894                                 ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
 895                                 if (ifp)
 896                                         goto have_ifp;
 897                         }
 898                 }
 899
 900                 idev = in6_dev_get(dev);
 901                 if (!idev) {
 902                         /* XXX: count this drop? */
 903                         return;
 904                 }
 905
 906                 if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
 907                     (idev->cnf.forwarding &&
 908                      (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
 909                      (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
 910                         if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
 911                             skb->pkt_type != PACKET_HOST &&
 912                             inc &&
 913                             NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
 914                                 /*
 915                                  * for anycast or proxy,
 916                                  * sender should delay its response
 917                                  * by a random time between 0 and
 918                                  * MAX_ANYCAST_DELAY_TIME seconds.
 919                                  * (RFC2461) -- yoshfuji
 920                                  */
 921                                 struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
 922                                 if (n)
 923                                         pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
 924                                 goto out;
 925                         }
 926                 } else
 927                         goto out;
 928         }
 929
 930         if (is_router < 0)
 931                 is_router = idev->cnf.forwarding;
 932
 933         if (dad) {
 934                 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
 935                               !!is_router, false, (ifp != NULL), true);
 936                 goto out;
 937         }
 938
 939         if (inc)
 940                 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
 941         else
 942                 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);
 943
 944         /*
 945          *      update / create cache entry
 946          *      for the source address
 947          */
 948         neigh = __neigh_lookup(&nd_tbl, saddr, dev,
 949                                !inc || lladdr || !dev->addr_len);
 950         if (neigh)
 951                 ndisc_update(dev, neigh, lladdr, NUD_STALE,
 952                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
 953                              NEIGH_UPDATE_F_OVERRIDE,
 954                              NDISC_NEIGHBOUR_SOLICITATION, &ndopts);
 955         if (neigh || !dev->header_ops) {
 956                 ndisc_send_na(dev, saddr, &msg->target, !!is_router,
 957                               true, (ifp != NULL && inc), inc);
 958                 if (neigh)
 959                         neigh_release(neigh);
 960         }
 961
 962 out:
 963         if (ifp)
 964                 in6_ifa_put(ifp);
 965         else
 966                 in6_dev_put(idev);
 967 }
 968
 969 static void ndisc_recv_na(struct sk_buff *skb)
 970 {
 971         struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
 972         struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
 973         const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
 974         u8 *lladdr = NULL;
 975         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 976                                     offsetof(struct nd_msg, opt));
 977         struct ndisc_options ndopts;
 978         struct net_device *dev = skb->dev;
 979         struct inet6_dev *idev = __in6_dev_get(dev);
 980         struct inet6_ifaddr *ifp;
 981         struct neighbour *neigh;
 982
 983         if (skb->len < sizeof(struct nd_msg)) {
 984                 ND_PRINTK(2, warn, "NA: packet too short\n");
 985                 return;
 986         }
 987
 988         if (ipv6_addr_is_multicast(&msg->target)) {
 989                 ND_PRINTK(2, warn, "NA: target address is multicast\n");
 990                 return;
 991         }
 992
 993         if (ipv6_addr_is_multicast(daddr) &&
 994             msg->icmph.icmp6_solicited) {
 995                 ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
 996                 return;
 997         }
 998
 999         /* For some 802.11 wireless deployments (and possibly other networks),
1000          * there will be a NA proxy and unsolicitd packets are attacks
1001          * and thus should not be accepted.
1002          */
1003         if (!msg->icmph.icmp6_solicited && idev &&
1004             idev->cnf.drop_unsolicited_na)
1005                 return;
1006
1007         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
1008                 ND_PRINTK(2, warn, "NS: invalid ND option\n");
1009                 return;
1010         }
1011         if (ndopts.nd_opts_tgt_lladdr) {
1012                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
1013                 if (!lladdr) {
1014                         ND_PRINTK(2, warn,
1015                                   "NA: invalid link-layer address length\n");
1016                         return;
1017                 }
1018         }
1019         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
1020         if (ifp) {
1021                 if (skb->pkt_type != PACKET_LOOPBACK
1022                     && (ifp->flags & IFA_F_TENTATIVE)) {
1023                                 addrconf_dad_failure(skb, ifp);
1024                                 return;
1025                 }
1026                 /* What should we make now? The advertisement
1027                    is invalid, but ndisc specs say nothing
1028                    about it. It could be misconfiguration, or
1029                    an smart proxy agent tries to help us :-)
1030
1031                    We should not print the error if NA has been
1032                    received from loopback - it is just our own
1033                    unsolicited advertisement.
1034                  */
1035                 if (skb->pkt_type != PACKET_LOOPBACK)
1036                         ND_PRINTK(1, warn,
1037                                   "NA: %pM advertised our address %pI6c on %s!\n",
1038                                   eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
1039                 in6_ifa_put(ifp);
1040                 return;
1041         }
1042         neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
1043
1044         if (neigh) {
1045                 u8 old_flags = neigh->flags;
1046                 struct net *net = dev_net(dev);
1047
1048                 if (neigh->nud_state & NUD_FAILED)
1049                         goto out;
1050
1051                 /*
1052                  * Don't update the neighbor cache entry on a proxy NA from
1053                  * ourselves because either the proxied node is off link or it
1054                  * has already sent a NA to us.
1055                  */
1056                 if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
1057                     net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
1058                     pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
1059                         /* XXX: idev->cnf.proxy_ndp */
1060                         goto out;
1061                 }
1062
1063                 ndisc_update(dev, neigh, lladdr,
1064                              msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE,
1065                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1066                              (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
1067                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1068                              (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
1069                              NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
1070
1071                 if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
1072                         /*
1073                          * Change: router to host
1074                          */
1075                         rt6_clean_tohost(dev_net(dev),  saddr);
1076                 }
1077
1078 out:
1079                 neigh_release(neigh);
1080         }
1081 }
1082
1083 static void ndisc_recv_rs(struct sk_buff *skb)
1084 {
1085         struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
1086         unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
1087         struct neighbour *neigh;
1088         struct inet6_dev *idev;
1089         const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
1090         struct ndisc_options ndopts;
1091         u8 *lladdr = NULL;
1092
1093         if (skb->len < sizeof(*rs_msg))
1094                 return;
1095
1096         idev = __in6_dev_get(skb->dev);
1097         if (!idev) {
1098                 ND_PRINTK(1, err, "RS: can't find in6 device\n");
1099                 return;
1100         }
1101
1102         /* Don't accept RS if we're not in router mode */
1103         if (!idev->cnf.forwarding)
1104                 goto out;
1105
1106         /*
1107          * Don't update NCE if src = ::;
1108          * this implies that the source node has no ip address assigned yet.
1109          */
1110         if (ipv6_addr_any(saddr))
1111                 goto out;
1112
1113         /* Parse ND options */
1114         if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) {
1115                 ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n");
1116                 goto out;
1117         }
1118
1119         if (ndopts.nd_opts_src_lladdr) {
1120                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1121                                              skb->dev);
1122                 if (!lladdr)
1123                         goto out;
1124         }
1125
1126         neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
1127         if (neigh) {
1128                 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1129                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1130                              NEIGH_UPDATE_F_OVERRIDE|
1131                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
1132                              NDISC_ROUTER_SOLICITATION, &ndopts);
1133                 neigh_release(neigh);
1134         }
1135 out:
1136         return;
1137 }
1138
1139 static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
1140 {
1141         struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
1142         struct sk_buff *skb;
1143         struct nlmsghdr *nlh;
1144         struct nduseroptmsg *ndmsg;
1145         struct net *net = dev_net(ra->dev);
1146         int err;
1147         int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
1148                                     + (opt->nd_opt_len << 3));
1149         size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
1150
1151         skb = nlmsg_new(msg_size, GFP_ATOMIC);
1152         if (!skb) {
1153                 err = -ENOBUFS;
1154                 goto errout;
1155         }
1156
1157         nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
1158         if (!nlh) {
1159                 goto nla_put_failure;
1160         }
1161
1162         ndmsg = nlmsg_data(nlh);
1163         ndmsg->nduseropt_family = AF_INET6;
1164         ndmsg->nduseropt_ifindex = ra->dev->ifindex;
1165         ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
1166         ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
1167         ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
1168
1169         memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
1170
1171         if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr))
1172                 goto nla_put_failure;
1173         nlmsg_end(skb, nlh);
1174
1175         rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
1176         return;
1177
1178 nla_put_failure:
1179         nlmsg_free(skb);
1180         err = -EMSGSIZE;
1181 errout:
1182         rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
1183 }
1184
1185 static void ndisc_router_discovery(struct sk_buff *skb)
1186 {
1187         struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
1188         struct neighbour *neigh = NULL;
1189         struct inet6_dev *in6_dev;
1190         struct fib6_info *rt = NULL;
1191         u32 defrtr_usr_metric;
1192         struct net *net;
1193         int lifetime;
1194         struct ndisc_options ndopts;
1195         int optlen;
1196         unsigned int pref = 0;
1197         __u32 old_if_flags;
1198         bool send_ifinfo_notify = false;
1199
1200         __u8 *opt = (__u8 *)(ra_msg + 1);
1201
1202         optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
1203                 sizeof(struct ra_msg);
1204
1205         ND_PRINTK(2, info,
1206                   "RA: %s, dev: %s\n",
1207                   __func__, skb->dev->name);
1208         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1209                 ND_PRINTK(2, warn, "RA: source address is not link-local\n");
1210                 return;
1211         }
1212         if (optlen < 0) {
1213                 ND_PRINTK(2, warn, "RA: packet too short\n");
1214                 return;
1215         }
1216
1217 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1218         if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
1219                 ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
1220                 return;
1221         }
1222 #endif
1223
1224         /*
1225          *      set the RA_RECV flag in the interface
1226          */
1227
1228         in6_dev = __in6_dev_get(skb->dev);
1229         if (!in6_dev) {
1230                 ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
1231                           skb->dev->name);
1232                 return;
1233         }
1234
1235         if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
1236                 ND_PRINTK(2, warn, "RA: invalid ND options\n");
1237                 return;
1238         }
1239
1240         if (!ipv6_accept_ra(in6_dev)) {
1241                 ND_PRINTK(2, info,
1242                           "RA: %s, did not accept ra for dev: %s\n",
1243                           __func__, skb->dev->name);
1244                 goto skip_linkparms;
1245         }
1246
1247 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1248         /* skip link-specific parameters from interior routers */
1249         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1250                 ND_PRINTK(2, info,
1251                           "RA: %s, nodetype is NODEFAULT, dev: %s\n",
1252                           __func__, skb->dev->name);
1253                 goto skip_linkparms;
1254         }
1255 #endif
1256
1257         if (in6_dev->if_flags & IF_RS_SENT) {
1258                 /*
1259                  *      flag that an RA was received after an RS was sent
1260                  *      out on this interface.
1261                  */
1262                 in6_dev->if_flags |= IF_RA_RCVD;
1263         }
1264
1265         /*
1266          * Remember the managed/otherconf flags from most recently
1267          * received RA message (RFC 2462) -- yoshfuji
1268          */
1269         old_if_flags = in6_dev->if_flags;
1270         in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
1271                                 IF_RA_OTHERCONF)) |
1272                                 (ra_msg->icmph.icmp6_addrconf_managed ?
1273                                         IF_RA_MANAGED : 0) |
1274                                 (ra_msg->icmph.icmp6_addrconf_other ?
1275                                         IF_RA_OTHERCONF : 0);
1276
1277         if (old_if_flags != in6_dev->if_flags)
1278                 send_ifinfo_notify = true;
1279
1280         if (!in6_dev->cnf.accept_ra_defrtr) {
1281                 ND_PRINTK(2, info,
1282                           "RA: %s, defrtr is false for dev: %s\n",
1283                           __func__, skb->dev->name);
1284                 goto skip_defrtr;
1285         }
1286
1287         /* Do not accept RA with source-addr found on local machine unless
1288          * accept_ra_from_local is set to true.
1289          */
1290         net = dev_net(in6_dev->dev);
1291         if (!in6_dev->cnf.accept_ra_from_local &&
1292             ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
1293                 ND_PRINTK(2, info,
1294                           "RA from local address detected on dev: %s: default router ignored\n",
1295                           skb->dev->name);
1296                 goto skip_defrtr;
1297         }
1298
1299         lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
1300
1301 #ifdef CONFIG_IPV6_ROUTER_PREF
1302         pref = ra_msg->icmph.icmp6_router_pref;
1303         /* 10b is handled as if it were 00b (medium) */
1304         if (pref == ICMPV6_ROUTER_PREF_INVALID ||
1305             !in6_dev->cnf.accept_ra_rtr_pref)
1306                 pref = ICMPV6_ROUTER_PREF_MEDIUM;
1307 #endif
1308         /* routes added from RAs do not use nexthop objects */
1309         rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
1310         if (rt) {
1311                 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1312                                          rt->fib6_nh->fib_nh_dev, NULL,
1313                                           &ipv6_hdr(skb)->saddr);
1314                 if (!neigh) {
1315                         ND_PRINTK(0, err,
1316                                   "RA: %s got default router without neighbour\n",
1317                                   __func__);
1318                         fib6_info_release(rt);
1319                         return;
1320                 }
1321         }
1322         /* Set default route metric as specified by user */
1323         defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
1324         /* delete the route if lifetime is 0 or if metric needs change */
1325         if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
1326                 ip6_del_rt(net, rt, false);
1327                 rt = NULL;
1328         }
1329
1330         ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, metric: %d, for dev: %s\n",
1331                   rt, lifetime, defrtr_usr_metric, skb->dev->name);
1332         if (!rt && lifetime) {
1333                 ND_PRINTK(3, info, "RA: adding default router\n");
1334
1335                 rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
1336                                          skb->dev, pref, defrtr_usr_metric);
1337                 if (!rt) {
1338                         ND_PRINTK(0, err,
1339                                   "RA: %s failed to add default route\n",
1340                                   __func__);
1341                         return;
1342                 }
1343
1344                 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1345                                          rt->fib6_nh->fib_nh_dev, NULL,
1346                                           &ipv6_hdr(skb)->saddr);
1347                 if (!neigh) {
1348                         ND_PRINTK(0, err,
1349                                   "RA: %s got default router without neighbour\n",
1350                                   __func__);
1351                         fib6_info_release(rt);
1352                         return;
1353                 }
1354                 neigh->flags |= NTF_ROUTER;
1355         } else if (rt && IPV6_EXTRACT_PREF(rt->fib6_flags) != pref) {
1356                 struct nl_info nlinfo = {
1357                         .nl_net = net,
1358                 };
1359                 rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
1360                 inet6_rt_notify(RTM_NEWROUTE, rt, &nlinfo, NLM_F_REPLACE);
1361         }
1362
1363         if (rt)
1364                 fib6_set_expires(rt, jiffies + (HZ * lifetime));
1365         if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
1366             ra_msg->icmph.icmp6_hop_limit) {
1367                 if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
1368                         in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
1369                         fib6_metric_set(rt, RTAX_HOPLIMIT,
1370                                         ra_msg->icmph.icmp6_hop_limit);
1371                 } else {
1372                         ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n");
1373                 }
1374         }
1375
1376 skip_defrtr:
1377
1378         /*
1379          *      Update Reachable Time and Retrans Timer
1380          */
1381
1382         if (in6_dev->nd_parms) {
1383                 unsigned long rtime = ntohl(ra_msg->retrans_timer);
1384
1385                 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
1386                         rtime = (rtime*HZ)/1000;
1387                         if (rtime < HZ/100)
1388                                 rtime = HZ/100;
1389                         NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
1390                         in6_dev->tstamp = jiffies;
1391                         send_ifinfo_notify = true;
1392                 }
1393
1394                 rtime = ntohl(ra_msg->reachable_time);
1395                 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
1396                         rtime = (rtime*HZ)/1000;
1397
1398                         if (rtime < HZ/10)
1399                                 rtime = HZ/10;
1400
1401                         if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) {
1402                                 NEIGH_VAR_SET(in6_dev->nd_parms,
1403                                               BASE_REACHABLE_TIME, rtime);
1404                                 NEIGH_VAR_SET(in6_dev->nd_parms,
1405                                               GC_STALETIME, 3 * rtime);
1406                                 in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
1407                                 in6_dev->tstamp = jiffies;
1408                                 send_ifinfo_notify = true;
1409                         }
1410                 }
1411         }
1412
1413 skip_linkparms:
1414
1415         /*
1416          *      Process options.
1417          */
1418
1419         if (!neigh)
1420                 neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
1421                                        skb->dev, 1);
1422         if (neigh) {
1423                 u8 *lladdr = NULL;
1424                 if (ndopts.nd_opts_src_lladdr) {
1425                         lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1426                                                      skb->dev);
1427                         if (!lladdr) {
1428                                 ND_PRINTK(2, warn,
1429                                           "RA: invalid link-layer address length\n");
1430                                 goto out;
1431                         }
1432                 }
1433                 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1434                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1435                              NEIGH_UPDATE_F_OVERRIDE|
1436                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1437                              NEIGH_UPDATE_F_ISROUTER,
1438                              NDISC_ROUTER_ADVERTISEMENT, &ndopts);
1439         }
1440
1441         if (!ipv6_accept_ra(in6_dev)) {
1442                 ND_PRINTK(2, info,
1443                           "RA: %s, accept_ra is false for dev: %s\n",
1444                           __func__, skb->dev->name);
1445                 goto out;
1446         }
1447
1448 #ifdef CONFIG_IPV6_ROUTE_INFO
1449         if (!in6_dev->cnf.accept_ra_from_local &&
1450             ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
1451                           in6_dev->dev, 0)) {
1452                 ND_PRINTK(2, info,
1453                           "RA from local address detected on dev: %s: router info ignored.\n",
1454                           skb->dev->name);
1455                 goto skip_routeinfo;
1456         }
1457
1458         if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
1459                 struct nd_opt_hdr *p;
1460                 for (p = ndopts.nd_opts_ri;
1461                      p;
1462                      p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
1463                         struct route_info *ri = (struct route_info *)p;
1464 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1465                         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
1466                             ri->prefix_len == 0)
1467                                 continue;
1468 #endif
1469                         if (ri->prefix_len == 0 &&
1470                             !in6_dev->cnf.accept_ra_defrtr)
1471                                 continue;
1472                         if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
1473                                 continue;
1474                         if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
1475                                 continue;
1476                         rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
1477                                       &ipv6_hdr(skb)->saddr);
1478                 }
1479         }
1480
1481 skip_routeinfo:
1482 #endif
1483
1484 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1485         /* skip link-specific ndopts from interior routers */
1486         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1487                 ND_PRINTK(2, info,
1488                           "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
1489                           __func__, skb->dev->name);
1490                 goto out;
1491         }
1492 #endif
1493
1494         if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
1495                 struct nd_opt_hdr *p;
1496                 for (p = ndopts.nd_opts_pi;
1497                      p;
1498                      p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
1499                         addrconf_prefix_rcv(skb->dev, (u8 *)p,
1500                                             (p->nd_opt_len) << 3,
1501                                             ndopts.nd_opts_src_lladdr != NULL);
1502                 }
1503         }
1504
1505         if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
1506                 __be32 n;
1507                 u32 mtu;
1508
1509                 memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
1510                 mtu = ntohl(n);
1511
1512                 if (in6_dev->ra_mtu != mtu) {
1513                         in6_dev->ra_mtu = mtu;
1514                         send_ifinfo_notify = true;
1515                 }
1516
1517                 if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
1518                         ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
1519                 } else if (in6_dev->cnf.mtu6 != mtu) {
1520                         in6_dev->cnf.mtu6 = mtu;
1521                         fib6_metric_set(rt, RTAX_MTU, mtu);
1522                         rt6_mtu_change(skb->dev, mtu);
1523                 }
1524         }
1525
1526         if (ndopts.nd_useropts) {
1527                 struct nd_opt_hdr *p;
1528                 for (p = ndopts.nd_useropts;
1529                      p;
1530                      p = ndisc_next_useropt(skb->dev, p,
1531                                             ndopts.nd_useropts_end)) {
1532                         ndisc_ra_useropt(skb, p);
1533                 }
1534         }
1535
1536         if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
1537                 ND_PRINTK(2, warn, "RA: invalid RA options\n");
1538         }
1539 out:
1540         /* Send a notify if RA changed managed/otherconf flags or
1541          * timer settings or ra_mtu value
1542          */
1543         if (send_ifinfo_notify)
1544                 inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
1545
1546         fib6_info_release(rt);
1547         if (neigh)
1548                 neigh_release(neigh);
1549 }
1550
1551 static void ndisc_redirect_rcv(struct sk_buff *skb)
1552 {
1553         u8 *hdr;
1554         struct ndisc_options ndopts;
1555         struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
1556         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
1557                                     offsetof(struct rd_msg, opt));
1558
1559 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1560         switch (skb->ndisc_nodetype) {
1561         case NDISC_NODETYPE_HOST:
1562         case NDISC_NODETYPE_NODEFAULT:
1563                 ND_PRINTK(2, warn,
1564                           "Redirect: from host or unauthorized router\n");
1565                 return;
1566         }
1567 #endif
1568
1569         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1570                 ND_PRINTK(2, warn,
1571                           "Redirect: source address is not link-local\n");
1572                 return;
1573         }
1574
1575         if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
1576                 return;
1577
1578         if (!ndopts.nd_opts_rh) {
1579                 ip6_redirect_no_header(skb, dev_net(skb->dev),
1580                                         skb->dev->ifindex);
1581                 return;
1582         }
1583
1584         hdr = (u8 *)ndopts.nd_opts_rh;
1585         hdr += 8;
1586         if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
1587                 return;
1588
1589         icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
1590 }
1591
1592 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
1593                                            struct sk_buff *orig_skb,
1594                                            int rd_len)
1595 {
1596         u8 *opt = skb_put(skb, rd_len);
1597
1598         memset(opt, 0, 8);
1599         *(opt++) = ND_OPT_REDIRECT_HDR;
1600         *(opt++) = (rd_len >> 3);
1601         opt += 6;
1602
1603         skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
1604                       rd_len - 8);
1605 }
1606
1607 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
1608 {
1609         struct net_device *dev = skb->dev;
1610         struct net *net = dev_net(dev);
1611         struct sock *sk = net->ipv6.ndisc_sk;
1612         int optlen = 0;
1613         struct inet_peer *peer;
1614         struct sk_buff *buff;
1615         struct rd_msg *msg;
1616         struct in6_addr saddr_buf;
1617         struct rt6_info *rt;
1618         struct dst_entry *dst;
1619         struct flowi6 fl6;
1620         int rd_len;
1621         u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
1622            ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
1623         bool ret;
1624
1625         if (netif_is_l3_master(skb->dev)) {
1626                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
1627                 if (!dev)
1628                         return;
1629         }
1630
1631         if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
1632                 ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
1633                           dev->name);
1634                 return;
1635         }
1636
1637         if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
1638             ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
1639                 ND_PRINTK(2, warn,
1640                           "Redirect: target address is not link-local unicast\n");
1641                 return;
1642         }
1643
1644         icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
1645                          &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
1646
1647         dst = ip6_route_output(net, NULL, &fl6);
1648         if (dst->error) {
1649                 dst_release(dst);
1650                 return;
1651         }
1652         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
1653         if (IS_ERR(dst))
1654                 return;
1655
1656         rt = (struct rt6_info *) dst;
1657
1658         if (rt->rt6i_flags & RTF_GATEWAY) {
1659                 ND_PRINTK(2, warn,
1660                           "Redirect: destination is not a neighbour\n");
1661                 goto release;
1662         }
1663         peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
1664         ret = inet_peer_xrlim_allow(peer, 1*HZ);
1665         if (peer)
1666                 inet_putpeer(peer);
1667         if (!ret)
1668                 goto release;
1669
1670         if (dev->addr_len) {
1671                 struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
1672                 if (!neigh) {
1673                         ND_PRINTK(2, warn,
1674                                   "Redirect: no neigh for target address\n");
1675                         goto release;
1676                 }
1677
1678                 read_lock_bh(&neigh->lock);
1679                 if (neigh->nud_state & NUD_VALID) {
1680                         memcpy(ha_buf, neigh->ha, dev->addr_len);
1681                         read_unlock_bh(&neigh->lock);
1682                         ha = ha_buf;
1683                         optlen += ndisc_redirect_opt_addr_space(dev, neigh,
1684                                                                 ops_data_buf,
1685                                                                 &ops_data);
1686                 } else
1687                         read_unlock_bh(&neigh->lock);
1688
1689                 neigh_release(neigh);
1690         }
1691
1692         rd_len = min_t(unsigned int,
1693                        IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
1694                        skb->len + 8);
1695         rd_len &= ~0x7;
1696         optlen += rd_len;
1697
1698         buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
1699         if (!buff)
1700                 goto release;
1701
1702         msg = skb_put(buff, sizeof(*msg));
1703         *msg = (struct rd_msg) {
1704                 .icmph = {
1705                         .icmp6_type = NDISC_REDIRECT,
1706                 },
1707                 .target = *target,
1708                 .dest = ipv6_hdr(skb)->daddr,
1709         };
1710
1711         /*
1712          *      include target_address option
1713          */
1714
1715         if (ha)
1716                 ndisc_fill_redirect_addr_option(buff, ha, ops_data);
1717
1718         /*
1719          *      build redirect option and copy skb over to the new packet.
1720          */
1721
1722         if (rd_len)
1723                 ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
1724
1725         skb_dst_set(buff, dst);
1726         ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
1727         return;
1728
1729 release:
1730         dst_release(dst);
1731 }
1732
1733 static void pndisc_redo(struct sk_buff *skb)
1734 {
1735         ndisc_recv_ns(skb);
1736         kfree_skb(skb);
1737 }
1738
1739 static int ndisc_is_multicast(const void *pkey)
1740 {
1741         return ipv6_addr_is_multicast((struct in6_addr *)pkey);
1742 }
1743
1744 static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
1745 {
1746         struct inet6_dev *idev = __in6_dev_get(skb->dev);
1747
1748         if (!idev)
1749                 return true;
1750         if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
1751             idev->cnf.suppress_frag_ndisc) {
1752                 net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
1753                 return true;
1754         }
1755         return false;
1756 }
1757
1758 int ndisc_rcv(struct sk_buff *skb)
1759 {
1760         struct nd_msg *msg;
1761
1762         if (ndisc_suppress_frag_ndisc(skb))
1763                 return 0;
1764
1765         if (skb_linearize(skb))
1766                 return 0;
1767
1768         msg = (struct nd_msg *)skb_transport_header(skb);
1769
1770         __skb_push(skb, skb->data - skb_transport_header(skb));
1771
1772         if (ipv6_hdr(skb)->hop_limit != 255) {
1773                 ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
1774                           ipv6_hdr(skb)->hop_limit);
1775                 return 0;
1776         }
1777
1778         if (msg->icmph.icmp6_code != 0) {
1779                 ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
1780                           msg->icmph.icmp6_code);
1781                 return 0;
1782         }
1783
1784         switch (msg->icmph.icmp6_type) {
1785         case NDISC_NEIGHBOUR_SOLICITATION:
1786                 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
1787                 ndisc_recv_ns(skb);
1788                 break;
1789
1790         case NDISC_NEIGHBOUR_ADVERTISEMENT:
1791                 ndisc_recv_na(skb);
1792                 break;
1793
1794         case NDISC_ROUTER_SOLICITATION:
1795                 ndisc_recv_rs(skb);
1796                 break;
1797
1798         case NDISC_ROUTER_ADVERTISEMENT:
1799                 ndisc_router_discovery(skb);
1800                 break;
1801
1802         case NDISC_REDIRECT:
1803                 ndisc_redirect_rcv(skb);
1804                 break;
1805         }
1806
1807         return 0;
1808 }
1809
1810 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1811 {
1812         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1813         struct netdev_notifier_change_info *change_info;
1814         struct net *net = dev_net(dev);
1815         struct inet6_dev *idev;
1816         bool evict_nocarrier;
1817
1818         switch (event) {
1819         case NETDEV_CHANGEADDR:
1820                 neigh_changeaddr(&nd_tbl, dev);
1821                 fib6_run_gc(0, net, false);
1822                 fallthrough;
1823         case NETDEV_UP:
1824                 idev = in6_dev_get(dev);
1825                 if (!idev)
1826                         break;
1827                 if (idev->cnf.ndisc_notify ||
1828                     net->ipv6.devconf_all->ndisc_notify)
1829                         ndisc_send_unsol_na(dev);
1830                 in6_dev_put(idev);
1831                 break;
1832         case NETDEV_CHANGE:
1833                 idev = in6_dev_get(dev);
1834                 if (!idev)
1835                         evict_nocarrier = true;
1836                 else {
1837                         evict_nocarrier = idev->cnf.ndisc_evict_nocarrier &&
1838                                           net->ipv6.devconf_all->ndisc_evict_nocarrier;
1839                         in6_dev_put(idev);
1840                 }
1841
1842                 change_info = ptr;
1843                 if (change_info->flags_changed & IFF_NOARP)
1844                         neigh_changeaddr(&nd_tbl, dev);
1845                 if (evict_nocarrier && !netif_carrier_ok(dev))
1846                         neigh_carrier_down(&nd_tbl, dev);
1847                 break;
1848         case NETDEV_DOWN:
1849                 neigh_ifdown(&nd_tbl, dev);
1850                 fib6_run_gc(0, net, false);
1851                 break;
1852         case NETDEV_NOTIFY_PEERS:
1853                 ndisc_send_unsol_na(dev);
1854                 break;
1855         default:
1856                 break;
1857         }
1858
1859         return NOTIFY_DONE;
1860 }
1861
1862 static struct notifier_block ndisc_netdev_notifier = {
1863         .notifier_call = ndisc_netdev_event,
1864         .priority = ADDRCONF_NOTIFY_PRIORITY - 5,
1865 };
1866
1867 #ifdef CONFIG_SYSCTL
1868 static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
1869                                          const char *func, const char *dev_name)
1870 {
1871         static char warncomm[TASK_COMM_LEN];
1872         static int warned;
1873         if (strcmp(warncomm, current->comm) && warned < 5) {
1874                 strcpy(warncomm, current->comm);
1875                 pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
1876                         warncomm, func,
1877                         dev_name, ctl->procname,
1878                         dev_name, ctl->procname);
1879                 warned++;
1880         }
1881 }
1882
1883 int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
1884                 size_t *lenp, loff_t *ppos)
1885 {
1886         struct net_device *dev = ctl->extra1;
1887         struct inet6_dev *idev;
1888         int ret;
1889
1890         if ((strcmp(ctl->procname, "retrans_time") == 0) ||
1891             (strcmp(ctl->procname, "base_reachable_time") == 0))
1892                 ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
1893
1894         if (strcmp(ctl->procname, "retrans_time") == 0)
1895                 ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
1896
1897         else if (strcmp(ctl->procname, "base_reachable_time") == 0)
1898                 ret = neigh_proc_dointvec_jiffies(ctl, write,
1899                                                   buffer, lenp, ppos);
1900
1901         else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
1902                  (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
1903                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
1904                                                      buffer, lenp, ppos);
1905         else
1906                 ret = -1;
1907
1908         if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
1909                 if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
1910                         idev->nd_parms->reachable_time =
1911                                         neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
1912                 idev->tstamp = jiffies;
1913                 inet6_ifinfo_notify(RTM_NEWLINK, idev);
1914                 in6_dev_put(idev);
1915         }
1916         return ret;
1917 }
1918
1919
1920 #endif
1921
1922 static int __net_init ndisc_net_init(struct net *net)
1923 {
1924         struct ipv6_pinfo *np;
1925         struct sock *sk;
1926         int err;
1927
1928         err = inet_ctl_sock_create(&sk, PF_INET6,
1929                                    SOCK_RAW, IPPROTO_ICMPV6, net);
1930         if (err < 0) {
1931                 ND_PRINTK(0, err,
1932                           "NDISC: Failed to initialize the control socket (err %d)\n",
1933                           err);
1934                 return err;
1935         }
1936
1937         net->ipv6.ndisc_sk = sk;
1938
1939         np = inet6_sk(sk);
1940         np->hop_limit = 255;
1941         /* Do not loopback ndisc messages */
1942         np->mc_loop = 0;
1943
1944         return 0;
1945 }
1946
1947 static void __net_exit ndisc_net_exit(struct net *net)
1948 {
1949         inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
1950 }
1951
1952 static struct pernet_operations ndisc_net_ops = {
1953         .init = ndisc_net_init,
1954         .exit = ndisc_net_exit,
1955 };
1956
1957 int __init ndisc_init(void)
1958 {
1959         int err;
1960
1961         err = register_pernet_subsys(&ndisc_net_ops);
1962         if (err)
1963                 return err;
1964         /*
1965          * Initialize the neighbour table
1966          */
1967         neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
1968
1969 #ifdef CONFIG_SYSCTL
1970         err = neigh_sysctl_register(NULL, &nd_tbl.parms,
1971                                     ndisc_ifinfo_sysctl_change);
1972         if (err)
1973                 goto out_unregister_pernet;
1974 out:
1975 #endif
1976         return err;
1977
1978 #ifdef CONFIG_SYSCTL
1979 out_unregister_pernet:
1980         unregister_pernet_subsys(&ndisc_net_ops);
1981         goto out;
1982 #endif
1983 }
1984
1985 int __init ndisc_late_init(void)
1986 {
1987         return register_netdevice_notifier(&ndisc_netdev_notifier);
1988 }
1989
1990 void ndisc_late_cleanup(void)
1991 {
1992         unregister_netdevice_notifier(&ndisc_netdev_notifier);
1993 }
1994
1995 void ndisc_cleanup(void)
1996 {
1997 #ifdef CONFIG_SYSCTL
1998         neigh_sysctl_unregister(&nd_tbl.parms);
1999 #endif
2000         neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
2001         unregister_pernet_subsys(&ndisc_net_ops);
2002 }