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             <roque@di.fc.ul.pt>
   8  *      Mike Shaver             <shaver@ingenia.com>
   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_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
 132                         [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 133                         [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
 134                         [NEIGH_VAR_PROXY_QLEN] = 64,
 135                         [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
 136                         [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
 137                 },
 138         },
 139         .gc_interval =    30 * HZ,
 140         .gc_thresh1 =    128,
 141         .gc_thresh2 =    512,
 142         .gc_thresh3 =   1024,
 143 };
 144 EXPORT_SYMBOL_GPL(nd_tbl);
 145
 146 void __ndisc_fill_addr_option(struct sk_buff *skb, int type, const void *data,
 147                               int data_len, int pad)
 148 {
 149         int space = __ndisc_opt_addr_space(data_len, pad);
 150         u8 *opt = skb_put(skb, space);
 151
 152         opt[0] = type;
 153         opt[1] = space>>3;
 154
 155         memset(opt + 2, 0, pad);
 156         opt   += pad;
 157         space -= pad;
 158
 159         memcpy(opt+2, data, data_len);
 160         data_len += 2;
 161         opt += data_len;
 162         space -= data_len;
 163         if (space > 0)
 164                 memset(opt, 0, space);
 165 }
 166 EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option);
 167
 168 static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type,
 169                                           const void *data, u8 icmp6_type)
 170 {
 171         __ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len,
 172                                  ndisc_addr_option_pad(skb->dev->type));
 173         ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type);
 174 }
 175
 176 static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb,
 177                                                    void *ha,
 178                                                    const u8 *ops_data)
 179 {
 180         ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT);
 181         ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data);
 182 }
 183
 184 static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
 185                                             struct nd_opt_hdr *end)
 186 {
 187         int type;
 188         if (!cur || !end || cur >= end)
 189                 return NULL;
 190         type = cur->nd_opt_type;
 191         do {
 192                 cur = ((void *)cur) + (cur->nd_opt_len << 3);
 193         } while (cur < end && cur->nd_opt_type != type);
 194         return cur <= end && cur->nd_opt_type == type ? cur : NULL;
 195 }
 196
 197 static inline int ndisc_is_useropt(const struct net_device *dev,
 198                                    struct nd_opt_hdr *opt)
 199 {
 200         return opt->nd_opt_type == ND_OPT_RDNSS ||
 201                 opt->nd_opt_type == ND_OPT_DNSSL ||
 202                 opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
 203                 opt->nd_opt_type == ND_OPT_PREF64 ||
 204                 ndisc_ops_is_useropt(dev, opt->nd_opt_type);
 205 }
 206
 207 static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
 208                                              struct nd_opt_hdr *cur,
 209                                              struct nd_opt_hdr *end)
 210 {
 211         if (!cur || !end || cur >= end)
 212                 return NULL;
 213         do {
 214                 cur = ((void *)cur) + (cur->nd_opt_len << 3);
 215         } while (cur < end && !ndisc_is_useropt(dev, cur));
 216         return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
 217 }
 218
 219 struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
 220                                           u8 *opt, int opt_len,
 221                                           struct ndisc_options *ndopts)
 222 {
 223         struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
 224
 225         if (!nd_opt || opt_len < 0 || !ndopts)
 226                 return NULL;
 227         memset(ndopts, 0, sizeof(*ndopts));
 228         while (opt_len) {
 229                 int l;
 230                 if (opt_len < sizeof(struct nd_opt_hdr))
 231                         return NULL;
 232                 l = nd_opt->nd_opt_len << 3;
 233                 if (opt_len < l || l == 0)
 234                         return NULL;
 235                 if (ndisc_ops_parse_options(dev, nd_opt, ndopts))
 236                         goto next_opt;
 237                 switch (nd_opt->nd_opt_type) {
 238                 case ND_OPT_SOURCE_LL_ADDR:
 239                 case ND_OPT_TARGET_LL_ADDR:
 240                 case ND_OPT_MTU:
 241                 case ND_OPT_NONCE:
 242                 case ND_OPT_REDIRECT_HDR:
 243                         if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
 244                                 ND_PRINTK(2, warn,
 245                                           "%s: duplicated ND6 option found: type=%d\n",
 246                                           __func__, nd_opt->nd_opt_type);
 247                         } else {
 248                                 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
 249                         }
 250                         break;
 251                 case ND_OPT_PREFIX_INFO:
 252                         ndopts->nd_opts_pi_end = nd_opt;
 253                         if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
 254                                 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
 255                         break;
 256 #ifdef CONFIG_IPV6_ROUTE_INFO
 257                 case ND_OPT_ROUTE_INFO:
 258                         ndopts->nd_opts_ri_end = nd_opt;
 259                         if (!ndopts->nd_opts_ri)
 260                                 ndopts->nd_opts_ri = nd_opt;
 261                         break;
 262 #endif
 263                 default:
 264                         if (ndisc_is_useropt(dev, nd_opt)) {
 265                                 ndopts->nd_useropts_end = nd_opt;
 266                                 if (!ndopts->nd_useropts)
 267                                         ndopts->nd_useropts = nd_opt;
 268                         } else {
 269                                 /*
 270                                  * Unknown options must be silently ignored,
 271                                  * to accommodate future extension to the
 272                                  * protocol.
 273                                  */
 274                                 ND_PRINTK(2, notice,
 275                                           "%s: ignored unsupported option; type=%d, len=%d\n",
 276                                           __func__,
 277                                           nd_opt->nd_opt_type,
 278                                           nd_opt->nd_opt_len);
 279                         }
 280                 }
 281 next_opt:
 282                 opt_len -= l;
 283                 nd_opt = ((void *)nd_opt) + l;
 284         }
 285         return ndopts;
 286 }
 287
 288 int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
 289 {
 290         switch (dev->type) {
 291         case ARPHRD_ETHER:
 292         case ARPHRD_IEEE802:    /* Not sure. Check it later. --ANK */
 293         case ARPHRD_FDDI:
 294                 ipv6_eth_mc_map(addr, buf);
 295                 return 0;
 296         case ARPHRD_ARCNET:
 297                 ipv6_arcnet_mc_map(addr, buf);
 298                 return 0;
 299         case ARPHRD_INFINIBAND:
 300                 ipv6_ib_mc_map(addr, dev->broadcast, buf);
 301                 return 0;
 302         case ARPHRD_IPGRE:
 303                 return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
 304         default:
 305                 if (dir) {
 306                         memcpy(buf, dev->broadcast, dev->addr_len);
 307                         return 0;
 308                 }
 309         }
 310         return -EINVAL;
 311 }
 312 EXPORT_SYMBOL(ndisc_mc_map);
 313
 314 static u32 ndisc_hash(const void *pkey,
 315                       const struct net_device *dev,
 316                       __u32 *hash_rnd)
 317 {
 318         return ndisc_hashfn(pkey, dev, hash_rnd);
 319 }
 320
 321 static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
 322 {
 323         return neigh_key_eq128(n, pkey);
 324 }
 325
 326 static int ndisc_constructor(struct neighbour *neigh)
 327 {
 328         struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;
 329         struct net_device *dev = neigh->dev;
 330         struct inet6_dev *in6_dev;
 331         struct neigh_parms *parms;
 332         bool is_multicast = ipv6_addr_is_multicast(addr);
 333
 334         in6_dev = in6_dev_get(dev);
 335         if (!in6_dev) {
 336                 return -EINVAL;
 337         }
 338
 339         parms = in6_dev->nd_parms;
 340         __neigh_parms_put(neigh->parms);
 341         neigh->parms = neigh_parms_clone(parms);
 342
 343         neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
 344         if (!dev->header_ops) {
 345                 neigh->nud_state = NUD_NOARP;
 346                 neigh->ops = &ndisc_direct_ops;
 347                 neigh->output = neigh_direct_output;
 348         } else {
 349                 if (is_multicast) {
 350                         neigh->nud_state = NUD_NOARP;
 351                         ndisc_mc_map(addr, neigh->ha, dev, 1);
 352                 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
 353                         neigh->nud_state = NUD_NOARP;
 354                         memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
 355                         if (dev->flags&IFF_LOOPBACK)
 356                                 neigh->type = RTN_LOCAL;
 357                 } else if (dev->flags&IFF_POINTOPOINT) {
 358                         neigh->nud_state = NUD_NOARP;
 359                         memcpy(neigh->ha, dev->broadcast, dev->addr_len);
 360                 }
 361                 if (dev->header_ops->cache)
 362                         neigh->ops = &ndisc_hh_ops;
 363                 else
 364                         neigh->ops = &ndisc_generic_ops;
 365                 if (neigh->nud_state&NUD_VALID)
 366                         neigh->output = neigh->ops->connected_output;
 367                 else
 368                         neigh->output = neigh->ops->output;
 369         }
 370         in6_dev_put(in6_dev);
 371         return 0;
 372 }
 373
 374 static int pndisc_constructor(struct pneigh_entry *n)
 375 {
 376         struct in6_addr *addr = (struct in6_addr *)&n->key;
 377         struct in6_addr maddr;
 378         struct net_device *dev = n->dev;
 379
 380         if (!dev || !__in6_dev_get(dev))
 381                 return -EINVAL;
 382         addrconf_addr_solict_mult(addr, &maddr);
 383         ipv6_dev_mc_inc(dev, &maddr);
 384         return 0;
 385 }
 386
 387 static void pndisc_destructor(struct pneigh_entry *n)
 388 {
 389         struct in6_addr *addr = (struct in6_addr *)&n->key;
 390         struct in6_addr maddr;
 391         struct net_device *dev = n->dev;
 392
 393         if (!dev || !__in6_dev_get(dev))
 394                 return;
 395         addrconf_addr_solict_mult(addr, &maddr);
 396         ipv6_dev_mc_dec(dev, &maddr);
 397 }
 398
 399 /* called with rtnl held */
 400 static bool ndisc_allow_add(const struct net_device *dev,
 401                             struct netlink_ext_ack *extack)
 402 {
 403         struct inet6_dev *idev = __in6_dev_get(dev);
 404
 405         if (!idev || idev->cnf.disable_ipv6) {
 406                 NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
 407                 return false;
 408         }
 409
 410         return true;
 411 }
 412
 413 static struct sk_buff *ndisc_alloc_skb(struct net_device *dev,
 414                                        int len)
 415 {
 416         int hlen = LL_RESERVED_SPACE(dev);
 417         int tlen = dev->needed_tailroom;
 418         struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
 419         struct sk_buff *skb;
 420
 421         skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
 422         if (!skb) {
 423                 ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
 424                           __func__);
 425                 return NULL;
 426         }
 427
 428         skb->protocol = htons(ETH_P_IPV6);
 429         skb->dev = dev;
 430
 431         skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
 432         skb_reset_transport_header(skb);
 433
 434         /* Manually assign socket ownership as we avoid calling
 435          * sock_alloc_send_pskb() to bypass wmem buffer limits
 436          */
 437         skb_set_owner_w(skb, sk);
 438
 439         return skb;
 440 }
 441
 442 static void ip6_nd_hdr(struct sk_buff *skb,
 443                        const struct in6_addr *saddr,
 444                        const struct in6_addr *daddr,
 445                        int hop_limit, int len)
 446 {
 447         struct ipv6hdr *hdr;
 448         struct inet6_dev *idev;
 449         unsigned tclass;
 450
 451         rcu_read_lock();
 452         idev = __in6_dev_get(skb->dev);
 453         tclass = idev ? idev->cnf.ndisc_tclass : 0;
 454         rcu_read_unlock();
 455
 456         skb_push(skb, sizeof(*hdr));
 457         skb_reset_network_header(skb);
 458         hdr = ipv6_hdr(skb);
 459
 460         ip6_flow_hdr(hdr, tclass, 0);
 461
 462         hdr->payload_len = htons(len);
 463         hdr->nexthdr = IPPROTO_ICMPV6;
 464         hdr->hop_limit = hop_limit;
 465
 466         hdr->saddr = *saddr;
 467         hdr->daddr = *daddr;
 468 }
 469
 470 void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr,
 471                     const struct in6_addr *saddr)
 472 {
 473         struct dst_entry *dst = skb_dst(skb);
 474         struct net *net = dev_net(skb->dev);
 475         struct sock *sk = net->ipv6.ndisc_sk;
 476         struct inet6_dev *idev;
 477         int err;
 478         struct icmp6hdr *icmp6h = icmp6_hdr(skb);
 479         u8 type;
 480
 481         type = icmp6h->icmp6_type;
 482
 483         if (!dst) {
 484                 struct flowi6 fl6;
 485                 int oif = skb->dev->ifindex;
 486
 487                 icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif);
 488                 dst = icmp6_dst_alloc(skb->dev, &fl6);
 489                 if (IS_ERR(dst)) {
 490                         kfree_skb(skb);
 491                         return;
 492                 }
 493
 494                 skb_dst_set(skb, dst);
 495         }
 496
 497         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len,
 498                                               IPPROTO_ICMPV6,
 499                                               csum_partial(icmp6h,
 500                                                            skb->len, 0));
 501
 502         ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len);
 503
 504         rcu_read_lock();
 505         idev = __in6_dev_get(dst->dev);
 506         IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 507
 508         err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 509                       net, sk, skb, NULL, dst->dev,
 510                       dst_output);
 511         if (!err) {
 512                 ICMP6MSGOUT_INC_STATS(net, idev, type);
 513                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
 514         }
 515
 516         rcu_read_unlock();
 517 }
 518 EXPORT_SYMBOL(ndisc_send_skb);
 519
 520 void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
 521                    const struct in6_addr *solicited_addr,
 522                    bool router, bool solicited, bool override, bool inc_opt)
 523 {
 524         struct sk_buff *skb;
 525         struct in6_addr tmpaddr;
 526         struct inet6_ifaddr *ifp;
 527         const struct in6_addr *src_addr;
 528         struct nd_msg *msg;
 529         int optlen = 0;
 530
 531         /* for anycast or proxy, solicited_addr != src_addr */
 532         ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
 533         if (ifp) {
 534                 src_addr = solicited_addr;
 535                 if (ifp->flags & IFA_F_OPTIMISTIC)
 536                         override = false;
 537                 inc_opt |= ifp->idev->cnf.force_tllao;
 538                 in6_ifa_put(ifp);
 539         } else {
 540                 if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
 541                                        inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
 542                                        &tmpaddr))
 543                         return;
 544                 src_addr = &tmpaddr;
 545         }
 546
 547         if (!dev->addr_len)
 548                 inc_opt = false;
 549         if (inc_opt)
 550                 optlen += ndisc_opt_addr_space(dev,
 551                                                NDISC_NEIGHBOUR_ADVERTISEMENT);
 552
 553         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 554         if (!skb)
 555                 return;
 556
 557         msg = skb_put(skb, sizeof(*msg));
 558         *msg = (struct nd_msg) {
 559                 .icmph = {
 560                         .icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
 561                         .icmp6_router = router,
 562                         .icmp6_solicited = solicited,
 563                         .icmp6_override = override,
 564                 },
 565                 .target = *solicited_addr,
 566         };
 567
 568         if (inc_opt)
 569                 ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
 570                                        dev->dev_addr,
 571                                        NDISC_NEIGHBOUR_ADVERTISEMENT);
 572
 573         ndisc_send_skb(skb, daddr, src_addr);
 574 }
 575
 576 static void ndisc_send_unsol_na(struct net_device *dev)
 577 {
 578         struct inet6_dev *idev;
 579         struct inet6_ifaddr *ifa;
 580
 581         idev = in6_dev_get(dev);
 582         if (!idev)
 583                 return;
 584
 585         read_lock_bh(&idev->lock);
 586         list_for_each_entry(ifa, &idev->addr_list, if_list) {
 587                 /* skip tentative addresses until dad completes */
 588                 if (ifa->flags & IFA_F_TENTATIVE &&
 589                     !(ifa->flags & IFA_F_OPTIMISTIC))
 590                         continue;
 591
 592                 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
 593                               /*router=*/ !!idev->cnf.forwarding,
 594                               /*solicited=*/ false, /*override=*/ true,
 595                               /*inc_opt=*/ true);
 596         }
 597         read_unlock_bh(&idev->lock);
 598
 599         in6_dev_put(idev);
 600 }
 601
 602 struct sk_buff *ndisc_ns_create(struct net_device *dev, const struct in6_addr *solicit,
 603                                 const struct in6_addr *saddr, u64 nonce)
 604 {
 605         int inc_opt = dev->addr_len;
 606         struct sk_buff *skb;
 607         struct nd_msg *msg;
 608         int optlen = 0;
 609
 610         if (!saddr)
 611                 return NULL;
 612
 613         if (ipv6_addr_any(saddr))
 614                 inc_opt = false;
 615         if (inc_opt)
 616                 optlen += ndisc_opt_addr_space(dev,
 617                                                NDISC_NEIGHBOUR_SOLICITATION);
 618         if (nonce != 0)
 619                 optlen += 8;
 620
 621         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 622         if (!skb)
 623                 return NULL;
 624
 625         msg = skb_put(skb, sizeof(*msg));
 626         *msg = (struct nd_msg) {
 627                 .icmph = {
 628                         .icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
 629                 },
 630                 .target = *solicit,
 631         };
 632
 633         if (inc_opt)
 634                 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
 635                                        dev->dev_addr,
 636                                        NDISC_NEIGHBOUR_SOLICITATION);
 637         if (nonce != 0) {
 638                 u8 *opt = skb_put(skb, 8);
 639
 640                 opt[0] = ND_OPT_NONCE;
 641                 opt[1] = 8 >> 3;
 642                 memcpy(opt + 2, &nonce, 6);
 643         }
 644
 645         return skb;
 646 }
 647 EXPORT_SYMBOL(ndisc_ns_create);
 648
 649 void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
 650                    const struct in6_addr *daddr, const struct in6_addr *saddr,
 651                    u64 nonce)
 652 {
 653         struct in6_addr addr_buf;
 654         struct sk_buff *skb;
 655
 656         if (!saddr) {
 657                 if (ipv6_get_lladdr(dev, &addr_buf,
 658                                     (IFA_F_TENTATIVE | IFA_F_OPTIMISTIC)))
 659                         return;
 660                 saddr = &addr_buf;
 661         }
 662
 663         skb = ndisc_ns_create(dev, solicit, saddr, nonce);
 664
 665         if (skb)
 666                 ndisc_send_skb(skb, daddr, saddr);
 667 }
 668
 669 void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
 670                    const struct in6_addr *daddr)
 671 {
 672         struct sk_buff *skb;
 673         struct rs_msg *msg;
 674         int send_sllao = dev->addr_len;
 675         int optlen = 0;
 676
 677 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 678         /*
 679          * According to section 2.2 of RFC 4429, we must not
 680          * send router solicitations with a sllao from
 681          * optimistic addresses, but we may send the solicitation
 682          * if we don't include the sllao.  So here we check
 683          * if our address is optimistic, and if so, we
 684          * suppress the inclusion of the sllao.
 685          */
 686         if (send_sllao) {
 687                 struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
 688                                                            dev, 1);
 689                 if (ifp) {
 690                         if (ifp->flags & IFA_F_OPTIMISTIC)  {
 691                                 send_sllao = 0;
 692                         }
 693                         in6_ifa_put(ifp);
 694                 } else {
 695                         send_sllao = 0;
 696                 }
 697         }
 698 #endif
 699         if (send_sllao)
 700                 optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION);
 701
 702         skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
 703         if (!skb)
 704                 return;
 705
 706         msg = skb_put(skb, sizeof(*msg));
 707         *msg = (struct rs_msg) {
 708                 .icmph = {
 709                         .icmp6_type = NDISC_ROUTER_SOLICITATION,
 710                 },
 711         };
 712
 713         if (send_sllao)
 714                 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
 715                                        dev->dev_addr,
 716                                        NDISC_ROUTER_SOLICITATION);
 717
 718         ndisc_send_skb(skb, daddr, saddr);
 719 }
 720
 721
 722 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
 723 {
 724         /*
 725          *      "The sender MUST return an ICMP
 726          *       destination unreachable"
 727          */
 728         dst_link_failure(skb);
 729         kfree_skb(skb);
 730 }
 731
 732 /* Called with locked neigh: either read or both */
 733
 734 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
 735 {
 736         struct in6_addr *saddr = NULL;
 737         struct in6_addr mcaddr;
 738         struct net_device *dev = neigh->dev;
 739         struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
 740         int probes = atomic_read(&neigh->probes);
 741
 742         if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr,
 743                                            dev, false, 1,
 744                                            IFA_F_TENTATIVE|IFA_F_OPTIMISTIC))
 745                 saddr = &ipv6_hdr(skb)->saddr;
 746         probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
 747         if (probes < 0) {
 748                 if (!(neigh->nud_state & NUD_VALID)) {
 749                         ND_PRINTK(1, dbg,
 750                                   "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
 751                                   __func__, target);
 752                 }
 753                 ndisc_send_ns(dev, target, target, saddr, 0);
 754         } else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) {
 755                 neigh_app_ns(neigh);
 756         } else {
 757                 addrconf_addr_solict_mult(target, &mcaddr);
 758                 ndisc_send_ns(dev, target, &mcaddr, saddr, 0);
 759         }
 760 }
 761
 762 static int pndisc_is_router(const void *pkey,
 763                             struct net_device *dev)
 764 {
 765         struct pneigh_entry *n;
 766         int ret = -1;
 767
 768         read_lock_bh(&nd_tbl.lock);
 769         n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
 770         if (n)
 771                 ret = !!(n->flags & NTF_ROUTER);
 772         read_unlock_bh(&nd_tbl.lock);
 773
 774         return ret;
 775 }
 776
 777 void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
 778                   const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
 779                   struct ndisc_options *ndopts)
 780 {
 781         neigh_update(neigh, lladdr, new, flags, 0);
 782         /* report ndisc ops about neighbour update */
 783         ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
 784 }
 785
 786 static void ndisc_recv_ns(struct sk_buff *skb)
 787 {
 788         struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
 789         const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
 790         const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
 791         u8 *lladdr = NULL;
 792         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 793                                     offsetof(struct nd_msg, opt));
 794         struct ndisc_options ndopts;
 795         struct net_device *dev = skb->dev;
 796         struct inet6_ifaddr *ifp;
 797         struct inet6_dev *idev = NULL;
 798         struct neighbour *neigh;
 799         int dad = ipv6_addr_any(saddr);
 800         bool inc;
 801         int is_router = -1;
 802         u64 nonce = 0;
 803
 804         if (skb->len < sizeof(struct nd_msg)) {
 805                 ND_PRINTK(2, warn, "NS: packet too short\n");
 806                 return;
 807         }
 808
 809         if (ipv6_addr_is_multicast(&msg->target)) {
 810                 ND_PRINTK(2, warn, "NS: multicast target address\n");
 811                 return;
 812         }
 813
 814         /*
 815          * RFC2461 7.1.1:
 816          * DAD has to be destined for solicited node multicast address.
 817          */
 818         if (dad && !ipv6_addr_is_solict_mult(daddr)) {
 819                 ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
 820                 return;
 821         }
 822
 823         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
 824                 ND_PRINTK(2, warn, "NS: invalid ND options\n");
 825                 return;
 826         }
 827
 828         if (ndopts.nd_opts_src_lladdr) {
 829                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
 830                 if (!lladdr) {
 831                         ND_PRINTK(2, warn,
 832                                   "NS: invalid link-layer address length\n");
 833                         return;
 834                 }
 835
 836                 /* RFC2461 7.1.1:
 837                  *      If the IP source address is the unspecified address,
 838                  *      there MUST NOT be source link-layer address option
 839                  *      in the message.
 840                  */
 841                 if (dad) {
 842                         ND_PRINTK(2, warn,
 843                                   "NS: bad DAD packet (link-layer address option)\n");
 844                         return;
 845                 }
 846         }
 847         if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
 848                 memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
 849
 850         inc = ipv6_addr_is_multicast(daddr);
 851
 852         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
 853         if (ifp) {
 854 have_ifp:
 855                 if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
 856                         if (dad) {
 857                                 if (nonce != 0 && ifp->dad_nonce == nonce) {
 858                                         u8 *np = (u8 *)&nonce;
 859                                         /* Matching nonce if looped back */
 860                                         ND_PRINTK(2, notice,
 861                                                   "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
 862                                                   ifp->idev->dev->name,
 863                                                   &ifp->addr, np);
 864                                         goto out;
 865                                 }
 866                                 /*
 867                                  * We are colliding with another node
 868                                  * who is doing DAD
 869                                  * so fail our DAD process
 870                                  */
 871                                 addrconf_dad_failure(skb, ifp);
 872                                 return;
 873                         } else {
 874                                 /*
 875                                  * This is not a dad solicitation.
 876                                  * If we are an optimistic node,
 877                                  * we should respond.
 878                                  * Otherwise, we should ignore it.
 879                                  */
 880                                 if (!(ifp->flags & IFA_F_OPTIMISTIC))
 881                                         goto out;
 882                         }
 883                 }
 884
 885                 idev = ifp->idev;
 886         } else {
 887                 struct net *net = dev_net(dev);
 888
 889                 /* perhaps an address on the master device */
 890                 if (netif_is_l3_slave(dev)) {
 891                         struct net_device *mdev;
 892
 893                         mdev = netdev_master_upper_dev_get_rcu(dev);
 894                         if (mdev) {
 895                                 ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
 896                                 if (ifp)
 897                                         goto have_ifp;
 898                         }
 899                 }
 900
 901                 idev = in6_dev_get(dev);
 902                 if (!idev) {
 903                         /* XXX: count this drop? */
 904                         return;
 905                 }
 906
 907                 if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
 908                     (idev->cnf.forwarding &&
 909                      (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
 910                      (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
 911                         if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
 912                             skb->pkt_type != PACKET_HOST &&
 913                             inc &&
 914                             NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
 915                                 /*
 916                                  * for anycast or proxy,
 917                                  * sender should delay its response
 918                                  * by a random time between 0 and
 919                                  * MAX_ANYCAST_DELAY_TIME seconds.
 920                                  * (RFC2461) -- yoshfuji
 921                                  */
 922                                 struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
 923                                 if (n)
 924                                         pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
 925                                 goto out;
 926                         }
 927                 } else
 928                         goto out;
 929         }
 930
 931         if (is_router < 0)
 932                 is_router = idev->cnf.forwarding;
 933
 934         if (dad) {
 935                 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
 936                               !!is_router, false, (ifp != NULL), true);
 937                 goto out;
 938         }
 939
 940         if (inc)
 941                 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
 942         else
 943                 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);
 944
 945         /*
 946          *      update / create cache entry
 947          *      for the source address
 948          */
 949         neigh = __neigh_lookup(&nd_tbl, saddr, dev,
 950                                !inc || lladdr || !dev->addr_len);
 951         if (neigh)
 952                 ndisc_update(dev, neigh, lladdr, NUD_STALE,
 953                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
 954                              NEIGH_UPDATE_F_OVERRIDE,
 955                              NDISC_NEIGHBOUR_SOLICITATION, &ndopts);
 956         if (neigh || !dev->header_ops) {
 957                 ndisc_send_na(dev, saddr, &msg->target, !!is_router,
 958                               true, (ifp != NULL && inc), inc);
 959                 if (neigh)
 960                         neigh_release(neigh);
 961         }
 962
 963 out:
 964         if (ifp)
 965                 in6_ifa_put(ifp);
 966         else
 967                 in6_dev_put(idev);
 968 }
 969
 970 static int accept_untracked_na(struct net_device *dev, struct in6_addr *saddr)
 971 {
 972         struct inet6_dev *idev = __in6_dev_get(dev);
 973
 974         switch (idev->cnf.accept_untracked_na) {
 975         case 0: /* Don't accept untracked na (absent in neighbor cache) */
 976                 return 0;
 977         case 1: /* Create new entries from na if currently untracked */
 978                 return 1;
 979         case 2: /* Create new entries from untracked na only if saddr is in the
 980                  * same subnet as an address configured on the interface that
 981                  * received the na
 982                  */
 983                 return !!ipv6_chk_prefix(saddr, dev);
 984         default:
 985                 return 0;
 986         }
 987 }
 988
 989 static void ndisc_recv_na(struct sk_buff *skb)
 990 {
 991         struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
 992         struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
 993         const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
 994         u8 *lladdr = NULL;
 995         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 996                                     offsetof(struct nd_msg, opt));
 997         struct ndisc_options ndopts;
 998         struct net_device *dev = skb->dev;
 999         struct inet6_dev *idev = __in6_dev_get(dev);
1000         struct inet6_ifaddr *ifp;
1001         struct neighbour *neigh;
1002         u8 new_state;
1003
1004         if (skb->len < sizeof(struct nd_msg)) {
1005                 ND_PRINTK(2, warn, "NA: packet too short\n");
1006                 return;
1007         }
1008
1009         if (ipv6_addr_is_multicast(&msg->target)) {
1010                 ND_PRINTK(2, warn, "NA: target address is multicast\n");
1011                 return;
1012         }
1013
1014         if (ipv6_addr_is_multicast(daddr) &&
1015             msg->icmph.icmp6_solicited) {
1016                 ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
1017                 return;
1018         }
1019
1020         /* For some 802.11 wireless deployments (and possibly other networks),
1021          * there will be a NA proxy and unsolicitd packets are attacks
1022          * and thus should not be accepted.
1023          * drop_unsolicited_na takes precedence over accept_untracked_na
1024          */
1025         if (!msg->icmph.icmp6_solicited && idev &&
1026             idev->cnf.drop_unsolicited_na)
1027                 return;
1028
1029         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
1030                 ND_PRINTK(2, warn, "NS: invalid ND option\n");
1031                 return;
1032         }
1033         if (ndopts.nd_opts_tgt_lladdr) {
1034                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
1035                 if (!lladdr) {
1036                         ND_PRINTK(2, warn,
1037                                   "NA: invalid link-layer address length\n");
1038                         return;
1039                 }
1040         }
1041         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
1042         if (ifp) {
1043                 if (skb->pkt_type != PACKET_LOOPBACK
1044                     && (ifp->flags & IFA_F_TENTATIVE)) {
1045                                 addrconf_dad_failure(skb, ifp);
1046                                 return;
1047                 }
1048                 /* What should we make now? The advertisement
1049                    is invalid, but ndisc specs say nothing
1050                    about it. It could be misconfiguration, or
1051                    an smart proxy agent tries to help us :-)
1052
1053                    We should not print the error if NA has been
1054                    received from loopback - it is just our own
1055                    unsolicited advertisement.
1056                  */
1057                 if (skb->pkt_type != PACKET_LOOPBACK)
1058                         ND_PRINTK(1, warn,
1059                                   "NA: %pM advertised our address %pI6c on %s!\n",
1060                                   eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
1061                 in6_ifa_put(ifp);
1062                 return;
1063         }
1064
1065         neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
1066
1067         /* RFC 9131 updates original Neighbour Discovery RFC 4861.
1068          * NAs with Target LL Address option without a corresponding
1069          * entry in the neighbour cache can now create a STALE neighbour
1070          * cache entry on routers.
1071          *
1072          *   entry accept  fwding  solicited        behaviour
1073          * ------- ------  ------  ---------    ----------------------
1074          * present      X       X         0     Set state to STALE
1075          * present      X       X         1     Set state to REACHABLE
1076          *  absent      0       X         X     Do nothing
1077          *  absent      1       0         X     Do nothing
1078          *  absent      1       1         X     Add a new STALE entry
1079          *
1080          * Note that we don't do a (daddr == all-routers-mcast) check.
1081          */
1082         new_state = msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE;
1083         if (!neigh && lladdr && idev && idev->cnf.forwarding) {
1084                 if (accept_untracked_na(dev, saddr)) {
1085                         neigh = neigh_create(&nd_tbl, &msg->target, dev);
1086                         new_state = NUD_STALE;
1087                 }
1088         }
1089
1090         if (neigh && !IS_ERR(neigh)) {
1091                 u8 old_flags = neigh->flags;
1092                 struct net *net = dev_net(dev);
1093
1094                 if (neigh->nud_state & NUD_FAILED)
1095                         goto out;
1096
1097                 /*
1098                  * Don't update the neighbor cache entry on a proxy NA from
1099                  * ourselves because either the proxied node is off link or it
1100                  * has already sent a NA to us.
1101                  */
1102                 if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
1103                     net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
1104                     pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
1105                         /* XXX: idev->cnf.proxy_ndp */
1106                         goto out;
1107                 }
1108
1109                 ndisc_update(dev, neigh, lladdr,
1110                              new_state,
1111                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1112                              (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
1113                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1114                              (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
1115                              NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
1116
1117                 if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
1118                         /*
1119                          * Change: router to host
1120                          */
1121                         rt6_clean_tohost(dev_net(dev),  saddr);
1122                 }
1123
1124 out:
1125                 neigh_release(neigh);
1126         }
1127 }
1128
1129 static void ndisc_recv_rs(struct sk_buff *skb)
1130 {
1131         struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
1132         unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
1133         struct neighbour *neigh;
1134         struct inet6_dev *idev;
1135         const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
1136         struct ndisc_options ndopts;
1137         u8 *lladdr = NULL;
1138
1139         if (skb->len < sizeof(*rs_msg))
1140                 return;
1141
1142         idev = __in6_dev_get(skb->dev);
1143         if (!idev) {
1144                 ND_PRINTK(1, err, "RS: can't find in6 device\n");
1145                 return;
1146         }
1147
1148         /* Don't accept RS if we're not in router mode */
1149         if (!idev->cnf.forwarding)
1150                 goto out;
1151
1152         /*
1153          * Don't update NCE if src = ::;
1154          * this implies that the source node has no ip address assigned yet.
1155          */
1156         if (ipv6_addr_any(saddr))
1157                 goto out;
1158
1159         /* Parse ND options */
1160         if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) {
1161                 ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n");
1162                 goto out;
1163         }
1164
1165         if (ndopts.nd_opts_src_lladdr) {
1166                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1167                                              skb->dev);
1168                 if (!lladdr)
1169                         goto out;
1170         }
1171
1172         neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
1173         if (neigh) {
1174                 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1175                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1176                              NEIGH_UPDATE_F_OVERRIDE|
1177                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
1178                              NDISC_ROUTER_SOLICITATION, &ndopts);
1179                 neigh_release(neigh);
1180         }
1181 out:
1182         return;
1183 }
1184
1185 static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
1186 {
1187         struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
1188         struct sk_buff *skb;
1189         struct nlmsghdr *nlh;
1190         struct nduseroptmsg *ndmsg;
1191         struct net *net = dev_net(ra->dev);
1192         int err;
1193         int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
1194                                     + (opt->nd_opt_len << 3));
1195         size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
1196
1197         skb = nlmsg_new(msg_size, GFP_ATOMIC);
1198         if (!skb) {
1199                 err = -ENOBUFS;
1200                 goto errout;
1201         }
1202
1203         nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
1204         if (!nlh) {
1205                 goto nla_put_failure;
1206         }
1207
1208         ndmsg = nlmsg_data(nlh);
1209         ndmsg->nduseropt_family = AF_INET6;
1210         ndmsg->nduseropt_ifindex = ra->dev->ifindex;
1211         ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
1212         ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
1213         ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
1214
1215         memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
1216
1217         if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr))
1218                 goto nla_put_failure;
1219         nlmsg_end(skb, nlh);
1220
1221         rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
1222         return;
1223
1224 nla_put_failure:
1225         nlmsg_free(skb);
1226         err = -EMSGSIZE;
1227 errout:
1228         rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
1229 }
1230
1231 static void ndisc_router_discovery(struct sk_buff *skb)
1232 {
1233         struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
1234         struct neighbour *neigh = NULL;
1235         struct inet6_dev *in6_dev;
1236         struct fib6_info *rt = NULL;
1237         u32 defrtr_usr_metric;
1238         struct net *net;
1239         int lifetime;
1240         struct ndisc_options ndopts;
1241         int optlen;
1242         unsigned int pref = 0;
1243         __u32 old_if_flags;
1244         bool send_ifinfo_notify = false;
1245
1246         __u8 *opt = (__u8 *)(ra_msg + 1);
1247
1248         optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
1249                 sizeof(struct ra_msg);
1250
1251         ND_PRINTK(2, info,
1252                   "RA: %s, dev: %s\n",
1253                   __func__, skb->dev->name);
1254         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1255                 ND_PRINTK(2, warn, "RA: source address is not link-local\n");
1256                 return;
1257         }
1258         if (optlen < 0) {
1259                 ND_PRINTK(2, warn, "RA: packet too short\n");
1260                 return;
1261         }
1262
1263 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1264         if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
1265                 ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
1266                 return;
1267         }
1268 #endif
1269
1270         /*
1271          *      set the RA_RECV flag in the interface
1272          */
1273
1274         in6_dev = __in6_dev_get(skb->dev);
1275         if (!in6_dev) {
1276                 ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
1277                           skb->dev->name);
1278                 return;
1279         }
1280
1281         if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
1282                 ND_PRINTK(2, warn, "RA: invalid ND options\n");
1283                 return;
1284         }
1285
1286         if (!ipv6_accept_ra(in6_dev)) {
1287                 ND_PRINTK(2, info,
1288                           "RA: %s, did not accept ra for dev: %s\n",
1289                           __func__, skb->dev->name);
1290                 goto skip_linkparms;
1291         }
1292
1293 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1294         /* skip link-specific parameters from interior routers */
1295         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1296                 ND_PRINTK(2, info,
1297                           "RA: %s, nodetype is NODEFAULT, dev: %s\n",
1298                           __func__, skb->dev->name);
1299                 goto skip_linkparms;
1300         }
1301 #endif
1302
1303         if (in6_dev->if_flags & IF_RS_SENT) {
1304                 /*
1305                  *      flag that an RA was received after an RS was sent
1306                  *      out on this interface.
1307                  */
1308                 in6_dev->if_flags |= IF_RA_RCVD;
1309         }
1310
1311         /*
1312          * Remember the managed/otherconf flags from most recently
1313          * received RA message (RFC 2462) -- yoshfuji
1314          */
1315         old_if_flags = in6_dev->if_flags;
1316         in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
1317                                 IF_RA_OTHERCONF)) |
1318                                 (ra_msg->icmph.icmp6_addrconf_managed ?
1319                                         IF_RA_MANAGED : 0) |
1320                                 (ra_msg->icmph.icmp6_addrconf_other ?
1321                                         IF_RA_OTHERCONF : 0);
1322
1323         if (old_if_flags != in6_dev->if_flags)
1324                 send_ifinfo_notify = true;
1325
1326         if (!in6_dev->cnf.accept_ra_defrtr) {
1327                 ND_PRINTK(2, info,
1328                           "RA: %s, defrtr is false for dev: %s\n",
1329                           __func__, skb->dev->name);
1330                 goto skip_defrtr;
1331         }
1332
1333         /* Do not accept RA with source-addr found on local machine unless
1334          * accept_ra_from_local is set to true.
1335          */
1336         net = dev_net(in6_dev->dev);
1337         if (!in6_dev->cnf.accept_ra_from_local &&
1338             ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
1339                 ND_PRINTK(2, info,
1340                           "RA from local address detected on dev: %s: default router ignored\n",
1341                           skb->dev->name);
1342                 goto skip_defrtr;
1343         }
1344
1345         lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
1346
1347 #ifdef CONFIG_IPV6_ROUTER_PREF
1348         pref = ra_msg->icmph.icmp6_router_pref;
1349         /* 10b is handled as if it were 00b (medium) */
1350         if (pref == ICMPV6_ROUTER_PREF_INVALID ||
1351             !in6_dev->cnf.accept_ra_rtr_pref)
1352                 pref = ICMPV6_ROUTER_PREF_MEDIUM;
1353 #endif
1354         /* routes added from RAs do not use nexthop objects */
1355         rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
1356         if (rt) {
1357                 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1358                                          rt->fib6_nh->fib_nh_dev, NULL,
1359                                           &ipv6_hdr(skb)->saddr);
1360                 if (!neigh) {
1361                         ND_PRINTK(0, err,
1362                                   "RA: %s got default router without neighbour\n",
1363                                   __func__);
1364                         fib6_info_release(rt);
1365                         return;
1366                 }
1367         }
1368         /* Set default route metric as specified by user */
1369         defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
1370         /* delete the route if lifetime is 0 or if metric needs change */
1371         if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
1372                 ip6_del_rt(net, rt, false);
1373                 rt = NULL;
1374         }
1375
1376         ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, metric: %d, for dev: %s\n",
1377                   rt, lifetime, defrtr_usr_metric, skb->dev->name);
1378         if (!rt && lifetime) {
1379                 ND_PRINTK(3, info, "RA: adding default router\n");
1380
1381                 rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
1382                                          skb->dev, pref, defrtr_usr_metric);
1383                 if (!rt) {
1384                         ND_PRINTK(0, err,
1385                                   "RA: %s failed to add default route\n",
1386                                   __func__);
1387                         return;
1388                 }
1389
1390                 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1391                                          rt->fib6_nh->fib_nh_dev, NULL,
1392                                           &ipv6_hdr(skb)->saddr);
1393                 if (!neigh) {
1394                         ND_PRINTK(0, err,
1395                                   "RA: %s got default router without neighbour\n",
1396                                   __func__);
1397                         fib6_info_release(rt);
1398                         return;
1399                 }
1400                 neigh->flags |= NTF_ROUTER;
1401         } else if (rt && IPV6_EXTRACT_PREF(rt->fib6_flags) != pref) {
1402                 struct nl_info nlinfo = {
1403                         .nl_net = net,
1404                 };
1405                 rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
1406                 inet6_rt_notify(RTM_NEWROUTE, rt, &nlinfo, NLM_F_REPLACE);
1407         }
1408
1409         if (rt)
1410                 fib6_set_expires(rt, jiffies + (HZ * lifetime));
1411         if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
1412             ra_msg->icmph.icmp6_hop_limit) {
1413                 if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
1414                         in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
1415                         fib6_metric_set(rt, RTAX_HOPLIMIT,
1416                                         ra_msg->icmph.icmp6_hop_limit);
1417                 } else {
1418                         ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n");
1419                 }
1420         }
1421
1422 skip_defrtr:
1423
1424         /*
1425          *      Update Reachable Time and Retrans Timer
1426          */
1427
1428         if (in6_dev->nd_parms) {
1429                 unsigned long rtime = ntohl(ra_msg->retrans_timer);
1430
1431                 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
1432                         rtime = (rtime*HZ)/1000;
1433                         if (rtime < HZ/100)
1434                                 rtime = HZ/100;
1435                         NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
1436                         in6_dev->tstamp = jiffies;
1437                         send_ifinfo_notify = true;
1438                 }
1439
1440                 rtime = ntohl(ra_msg->reachable_time);
1441                 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
1442                         rtime = (rtime*HZ)/1000;
1443
1444                         if (rtime < HZ/10)
1445                                 rtime = HZ/10;
1446
1447                         if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) {
1448                                 NEIGH_VAR_SET(in6_dev->nd_parms,
1449                                               BASE_REACHABLE_TIME, rtime);
1450                                 NEIGH_VAR_SET(in6_dev->nd_parms,
1451                                               GC_STALETIME, 3 * rtime);
1452                                 in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
1453                                 in6_dev->tstamp = jiffies;
1454                                 send_ifinfo_notify = true;
1455                         }
1456                 }
1457         }
1458
1459 skip_linkparms:
1460
1461         /*
1462          *      Process options.
1463          */
1464
1465         if (!neigh)
1466                 neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
1467                                        skb->dev, 1);
1468         if (neigh) {
1469                 u8 *lladdr = NULL;
1470                 if (ndopts.nd_opts_src_lladdr) {
1471                         lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1472                                                      skb->dev);
1473                         if (!lladdr) {
1474                                 ND_PRINTK(2, warn,
1475                                           "RA: invalid link-layer address length\n");
1476                                 goto out;
1477                         }
1478                 }
1479                 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1480                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1481                              NEIGH_UPDATE_F_OVERRIDE|
1482                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1483                              NEIGH_UPDATE_F_ISROUTER,
1484                              NDISC_ROUTER_ADVERTISEMENT, &ndopts);
1485         }
1486
1487         if (!ipv6_accept_ra(in6_dev)) {
1488                 ND_PRINTK(2, info,
1489                           "RA: %s, accept_ra is false for dev: %s\n",
1490                           __func__, skb->dev->name);
1491                 goto out;
1492         }
1493
1494 #ifdef CONFIG_IPV6_ROUTE_INFO
1495         if (!in6_dev->cnf.accept_ra_from_local &&
1496             ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
1497                           in6_dev->dev, 0)) {
1498                 ND_PRINTK(2, info,
1499                           "RA from local address detected on dev: %s: router info ignored.\n",
1500                           skb->dev->name);
1501                 goto skip_routeinfo;
1502         }
1503
1504         if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
1505                 struct nd_opt_hdr *p;
1506                 for (p = ndopts.nd_opts_ri;
1507                      p;
1508                      p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
1509                         struct route_info *ri = (struct route_info *)p;
1510 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1511                         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
1512                             ri->prefix_len == 0)
1513                                 continue;
1514 #endif
1515                         if (ri->prefix_len == 0 &&
1516                             !in6_dev->cnf.accept_ra_defrtr)
1517                                 continue;
1518                         if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
1519                                 continue;
1520                         if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
1521                                 continue;
1522                         rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
1523                                       &ipv6_hdr(skb)->saddr);
1524                 }
1525         }
1526
1527 skip_routeinfo:
1528 #endif
1529
1530 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1531         /* skip link-specific ndopts from interior routers */
1532         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1533                 ND_PRINTK(2, info,
1534                           "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
1535                           __func__, skb->dev->name);
1536                 goto out;
1537         }
1538 #endif
1539
1540         if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
1541                 struct nd_opt_hdr *p;
1542                 for (p = ndopts.nd_opts_pi;
1543                      p;
1544                      p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
1545                         addrconf_prefix_rcv(skb->dev, (u8 *)p,
1546                                             (p->nd_opt_len) << 3,
1547                                             ndopts.nd_opts_src_lladdr != NULL);
1548                 }
1549         }
1550
1551         if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
1552                 __be32 n;
1553                 u32 mtu;
1554
1555                 memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
1556                 mtu = ntohl(n);
1557
1558                 if (in6_dev->ra_mtu != mtu) {
1559                         in6_dev->ra_mtu = mtu;
1560                         send_ifinfo_notify = true;
1561                 }
1562
1563                 if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
1564                         ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
1565                 } else if (in6_dev->cnf.mtu6 != mtu) {
1566                         in6_dev->cnf.mtu6 = mtu;
1567                         fib6_metric_set(rt, RTAX_MTU, mtu);
1568                         rt6_mtu_change(skb->dev, mtu);
1569                 }
1570         }
1571
1572         if (ndopts.nd_useropts) {
1573                 struct nd_opt_hdr *p;
1574                 for (p = ndopts.nd_useropts;
1575                      p;
1576                      p = ndisc_next_useropt(skb->dev, p,
1577                                             ndopts.nd_useropts_end)) {
1578                         ndisc_ra_useropt(skb, p);
1579                 }
1580         }
1581
1582         if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
1583                 ND_PRINTK(2, warn, "RA: invalid RA options\n");
1584         }
1585 out:
1586         /* Send a notify if RA changed managed/otherconf flags or
1587          * timer settings or ra_mtu value
1588          */
1589         if (send_ifinfo_notify)
1590                 inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
1591
1592         fib6_info_release(rt);
1593         if (neigh)
1594                 neigh_release(neigh);
1595 }
1596
1597 static void ndisc_redirect_rcv(struct sk_buff *skb)
1598 {
1599         u8 *hdr;
1600         struct ndisc_options ndopts;
1601         struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
1602         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
1603                                     offsetof(struct rd_msg, opt));
1604
1605 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1606         switch (skb->ndisc_nodetype) {
1607         case NDISC_NODETYPE_HOST:
1608         case NDISC_NODETYPE_NODEFAULT:
1609                 ND_PRINTK(2, warn,
1610                           "Redirect: from host or unauthorized router\n");
1611                 return;
1612         }
1613 #endif
1614
1615         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1616                 ND_PRINTK(2, warn,
1617                           "Redirect: source address is not link-local\n");
1618                 return;
1619         }
1620
1621         if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
1622                 return;
1623
1624         if (!ndopts.nd_opts_rh) {
1625                 ip6_redirect_no_header(skb, dev_net(skb->dev),
1626                                         skb->dev->ifindex);
1627                 return;
1628         }
1629
1630         hdr = (u8 *)ndopts.nd_opts_rh;
1631         hdr += 8;
1632         if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
1633                 return;
1634
1635         icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
1636 }
1637
1638 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
1639                                            struct sk_buff *orig_skb,
1640                                            int rd_len)
1641 {
1642         u8 *opt = skb_put(skb, rd_len);
1643
1644         memset(opt, 0, 8);
1645         *(opt++) = ND_OPT_REDIRECT_HDR;
1646         *(opt++) = (rd_len >> 3);
1647         opt += 6;
1648
1649         skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
1650                       rd_len - 8);
1651 }
1652
1653 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
1654 {
1655         struct net_device *dev = skb->dev;
1656         struct net *net = dev_net(dev);
1657         struct sock *sk = net->ipv6.ndisc_sk;
1658         int optlen = 0;
1659         struct inet_peer *peer;
1660         struct sk_buff *buff;
1661         struct rd_msg *msg;
1662         struct in6_addr saddr_buf;
1663         struct rt6_info *rt;
1664         struct dst_entry *dst;
1665         struct flowi6 fl6;
1666         int rd_len;
1667         u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
1668            ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
1669         bool ret;
1670
1671         if (netif_is_l3_master(skb->dev)) {
1672                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
1673                 if (!dev)
1674                         return;
1675         }
1676
1677         if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
1678                 ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
1679                           dev->name);
1680                 return;
1681         }
1682
1683         if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
1684             ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
1685                 ND_PRINTK(2, warn,
1686                           "Redirect: target address is not link-local unicast\n");
1687                 return;
1688         }
1689
1690         icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
1691                          &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
1692
1693         dst = ip6_route_output(net, NULL, &fl6);
1694         if (dst->error) {
1695                 dst_release(dst);
1696                 return;
1697         }
1698         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
1699         if (IS_ERR(dst))
1700                 return;
1701
1702         rt = (struct rt6_info *) dst;
1703
1704         if (rt->rt6i_flags & RTF_GATEWAY) {
1705                 ND_PRINTK(2, warn,
1706                           "Redirect: destination is not a neighbour\n");
1707                 goto release;
1708         }
1709         peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
1710         ret = inet_peer_xrlim_allow(peer, 1*HZ);
1711         if (peer)
1712                 inet_putpeer(peer);
1713         if (!ret)
1714                 goto release;
1715
1716         if (dev->addr_len) {
1717                 struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
1718                 if (!neigh) {
1719                         ND_PRINTK(2, warn,
1720                                   "Redirect: no neigh for target address\n");
1721                         goto release;
1722                 }
1723
1724                 read_lock_bh(&neigh->lock);
1725                 if (neigh->nud_state & NUD_VALID) {
1726                         memcpy(ha_buf, neigh->ha, dev->addr_len);
1727                         read_unlock_bh(&neigh->lock);
1728                         ha = ha_buf;
1729                         optlen += ndisc_redirect_opt_addr_space(dev, neigh,
1730                                                                 ops_data_buf,
1731                                                                 &ops_data);
1732                 } else
1733                         read_unlock_bh(&neigh->lock);
1734
1735                 neigh_release(neigh);
1736         }
1737
1738         rd_len = min_t(unsigned int,
1739                        IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
1740                        skb->len + 8);
1741         rd_len &= ~0x7;
1742         optlen += rd_len;
1743
1744         buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
1745         if (!buff)
1746                 goto release;
1747
1748         msg = skb_put(buff, sizeof(*msg));
1749         *msg = (struct rd_msg) {
1750                 .icmph = {
1751                         .icmp6_type = NDISC_REDIRECT,
1752                 },
1753                 .target = *target,
1754                 .dest = ipv6_hdr(skb)->daddr,
1755         };
1756
1757         /*
1758          *      include target_address option
1759          */
1760
1761         if (ha)
1762                 ndisc_fill_redirect_addr_option(buff, ha, ops_data);
1763
1764         /*
1765          *      build redirect option and copy skb over to the new packet.
1766          */
1767
1768         if (rd_len)
1769                 ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
1770
1771         skb_dst_set(buff, dst);
1772         ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
1773         return;
1774
1775 release:
1776         dst_release(dst);
1777 }
1778
1779 static void pndisc_redo(struct sk_buff *skb)
1780 {
1781         ndisc_recv_ns(skb);
1782         kfree_skb(skb);
1783 }
1784
1785 static int ndisc_is_multicast(const void *pkey)
1786 {
1787         return ipv6_addr_is_multicast((struct in6_addr *)pkey);
1788 }
1789
1790 static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
1791 {
1792         struct inet6_dev *idev = __in6_dev_get(skb->dev);
1793
1794         if (!idev)
1795                 return true;
1796         if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
1797             idev->cnf.suppress_frag_ndisc) {
1798                 net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
1799                 return true;
1800         }
1801         return false;
1802 }
1803
1804 int ndisc_rcv(struct sk_buff *skb)
1805 {
1806         struct nd_msg *msg;
1807
1808         if (ndisc_suppress_frag_ndisc(skb))
1809                 return 0;
1810
1811         if (skb_linearize(skb))
1812                 return 0;
1813
1814         msg = (struct nd_msg *)skb_transport_header(skb);
1815
1816         __skb_push(skb, skb->data - skb_transport_header(skb));
1817
1818         if (ipv6_hdr(skb)->hop_limit != 255) {
1819                 ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
1820                           ipv6_hdr(skb)->hop_limit);
1821                 return 0;
1822         }
1823
1824         if (msg->icmph.icmp6_code != 0) {
1825                 ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
1826                           msg->icmph.icmp6_code);
1827                 return 0;
1828         }
1829
1830         switch (msg->icmph.icmp6_type) {
1831         case NDISC_NEIGHBOUR_SOLICITATION:
1832                 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
1833                 ndisc_recv_ns(skb);
1834                 break;
1835
1836         case NDISC_NEIGHBOUR_ADVERTISEMENT:
1837                 ndisc_recv_na(skb);
1838                 break;
1839
1840         case NDISC_ROUTER_SOLICITATION:
1841                 ndisc_recv_rs(skb);
1842                 break;
1843
1844         case NDISC_ROUTER_ADVERTISEMENT:
1845                 ndisc_router_discovery(skb);
1846                 break;
1847
1848         case NDISC_REDIRECT:
1849                 ndisc_redirect_rcv(skb);
1850                 break;
1851         }
1852
1853         return 0;
1854 }
1855
1856 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1857 {
1858         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1859         struct netdev_notifier_change_info *change_info;
1860         struct net *net = dev_net(dev);
1861         struct inet6_dev *idev;
1862         bool evict_nocarrier;
1863
1864         switch (event) {
1865         case NETDEV_CHANGEADDR:
1866                 neigh_changeaddr(&nd_tbl, dev);
1867                 fib6_run_gc(0, net, false);
1868                 fallthrough;
1869         case NETDEV_UP:
1870                 idev = in6_dev_get(dev);
1871                 if (!idev)
1872                         break;
1873                 if (idev->cnf.ndisc_notify ||
1874                     net->ipv6.devconf_all->ndisc_notify)
1875                         ndisc_send_unsol_na(dev);
1876                 in6_dev_put(idev);
1877                 break;
1878         case NETDEV_CHANGE:
1879                 idev = in6_dev_get(dev);
1880                 if (!idev)
1881                         evict_nocarrier = true;
1882                 else {
1883                         evict_nocarrier = idev->cnf.ndisc_evict_nocarrier &&
1884                                           net->ipv6.devconf_all->ndisc_evict_nocarrier;
1885                         in6_dev_put(idev);
1886                 }
1887
1888                 change_info = ptr;
1889                 if (change_info->flags_changed & IFF_NOARP)
1890                         neigh_changeaddr(&nd_tbl, dev);
1891                 if (evict_nocarrier && !netif_carrier_ok(dev))
1892                         neigh_carrier_down(&nd_tbl, dev);
1893                 break;
1894         case NETDEV_DOWN:
1895                 neigh_ifdown(&nd_tbl, dev);
1896                 fib6_run_gc(0, net, false);
1897                 break;
1898         case NETDEV_NOTIFY_PEERS:
1899                 ndisc_send_unsol_na(dev);
1900                 break;
1901         default:
1902                 break;
1903         }
1904
1905         return NOTIFY_DONE;
1906 }
1907
1908 static struct notifier_block ndisc_netdev_notifier = {
1909         .notifier_call = ndisc_netdev_event,
1910         .priority = ADDRCONF_NOTIFY_PRIORITY - 5,
1911 };
1912
1913 #ifdef CONFIG_SYSCTL
1914 static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
1915                                          const char *func, const char *dev_name)
1916 {
1917         static char warncomm[TASK_COMM_LEN];
1918         static int warned;
1919         if (strcmp(warncomm, current->comm) && warned < 5) {
1920                 strcpy(warncomm, current->comm);
1921                 pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
1922                         warncomm, func,
1923                         dev_name, ctl->procname,
1924                         dev_name, ctl->procname);
1925                 warned++;
1926         }
1927 }
1928
1929 int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
1930                 size_t *lenp, loff_t *ppos)
1931 {
1932         struct net_device *dev = ctl->extra1;
1933         struct inet6_dev *idev;
1934         int ret;
1935
1936         if ((strcmp(ctl->procname, "retrans_time") == 0) ||
1937             (strcmp(ctl->procname, "base_reachable_time") == 0))
1938                 ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
1939
1940         if (strcmp(ctl->procname, "retrans_time") == 0)
1941                 ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
1942
1943         else if (strcmp(ctl->procname, "base_reachable_time") == 0)
1944                 ret = neigh_proc_dointvec_jiffies(ctl, write,
1945                                                   buffer, lenp, ppos);
1946
1947         else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
1948                  (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
1949                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
1950                                                      buffer, lenp, ppos);
1951         else
1952                 ret = -1;
1953
1954         if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
1955                 if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
1956                         idev->nd_parms->reachable_time =
1957                                         neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
1958                 idev->tstamp = jiffies;
1959                 inet6_ifinfo_notify(RTM_NEWLINK, idev);
1960                 in6_dev_put(idev);
1961         }
1962         return ret;
1963 }
1964
1965
1966 #endif
1967
1968 static int __net_init ndisc_net_init(struct net *net)
1969 {
1970         struct ipv6_pinfo *np;
1971         struct sock *sk;
1972         int err;
1973
1974         err = inet_ctl_sock_create(&sk, PF_INET6,
1975                                    SOCK_RAW, IPPROTO_ICMPV6, net);
1976         if (err < 0) {
1977                 ND_PRINTK(0, err,
1978                           "NDISC: Failed to initialize the control socket (err %d)\n",
1979                           err);
1980                 return err;
1981         }
1982
1983         net->ipv6.ndisc_sk = sk;
1984
1985         np = inet6_sk(sk);
1986         np->hop_limit = 255;
1987         /* Do not loopback ndisc messages */
1988         np->mc_loop = 0;
1989
1990         return 0;
1991 }
1992
1993 static void __net_exit ndisc_net_exit(struct net *net)
1994 {
1995         inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
1996 }
1997
1998 static struct pernet_operations ndisc_net_ops = {
1999         .init = ndisc_net_init,
2000         .exit = ndisc_net_exit,
2001 };
2002
2003 int __init ndisc_init(void)
2004 {
2005         int err;
2006
2007         err = register_pernet_subsys(&ndisc_net_ops);
2008         if (err)
2009                 return err;
2010         /*
2011          * Initialize the neighbour table
2012          */
2013         neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
2014
2015 #ifdef CONFIG_SYSCTL
2016         err = neigh_sysctl_register(NULL, &nd_tbl.parms,
2017                                     ndisc_ifinfo_sysctl_change);
2018         if (err)
2019                 goto out_unregister_pernet;
2020 out:
2021 #endif
2022         return err;
2023
2024 #ifdef CONFIG_SYSCTL
2025 out_unregister_pernet:
2026         unregister_pernet_subsys(&ndisc_net_ops);
2027         goto out;
2028 #endif
2029 }
2030
2031 int __init ndisc_late_init(void)
2032 {
2033         return register_netdevice_notifier(&ndisc_netdev_notifier);
2034 }
2035
2036 void ndisc_late_cleanup(void)
2037 {
2038         unregister_netdevice_notifier(&ndisc_netdev_notifier);
2039 }
2040
2041 void ndisc_cleanup(void)
2042 {
2043 #ifdef CONFIG_SYSCTL
2044         neigh_sysctl_unregister(&nd_tbl.parms);
2045 #endif
2046         neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
2047         unregister_pernet_subsys(&ndisc_net_ops);
2048 }