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_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 enum skb_drop_reason 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         int is_router = -1;
 801         SKB_DR(reason);
 802         u64 nonce = 0;
 803         bool inc;
 804
 805         if (skb->len < sizeof(struct nd_msg))
 806                 return SKB_DROP_REASON_PKT_TOO_SMALL;
 807
 808         if (ipv6_addr_is_multicast(&msg->target)) {
 809                 ND_PRINTK(2, warn, "NS: multicast target address\n");
 810                 return reason;
 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 reason;
 820         }
 821
 822         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
 823                 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
 824
 825         if (ndopts.nd_opts_src_lladdr) {
 826                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
 827                 if (!lladdr) {
 828                         ND_PRINTK(2, warn,
 829                                   "NS: invalid link-layer address length\n");
 830                         return reason;
 831                 }
 832
 833                 /* RFC2461 7.1.1:
 834                  *      If the IP source address is the unspecified address,
 835                  *      there MUST NOT be source link-layer address option
 836                  *      in the message.
 837                  */
 838                 if (dad) {
 839                         ND_PRINTK(2, warn,
 840                                   "NS: bad DAD packet (link-layer address option)\n");
 841                         return reason;
 842                 }
 843         }
 844         if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
 845                 memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
 846
 847         inc = ipv6_addr_is_multicast(daddr);
 848
 849         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
 850         if (ifp) {
 851 have_ifp:
 852                 if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
 853                         if (dad) {
 854                                 if (nonce != 0 && ifp->dad_nonce == nonce) {
 855                                         u8 *np = (u8 *)&nonce;
 856                                         /* Matching nonce if looped back */
 857                                         ND_PRINTK(2, notice,
 858                                                   "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
 859                                                   ifp->idev->dev->name,
 860                                                   &ifp->addr, np);
 861                                         goto out;
 862                                 }
 863                                 /*
 864                                  * We are colliding with another node
 865                                  * who is doing DAD
 866                                  * so fail our DAD process
 867                                  */
 868                                 addrconf_dad_failure(skb, ifp);
 869                                 return reason;
 870                         } else {
 871                                 /*
 872                                  * This is not a dad solicitation.
 873                                  * If we are an optimistic node,
 874                                  * we should respond.
 875                                  * Otherwise, we should ignore it.
 876                                  */
 877                                 if (!(ifp->flags & IFA_F_OPTIMISTIC))
 878                                         goto out;
 879                         }
 880                 }
 881
 882                 idev = ifp->idev;
 883         } else {
 884                 struct net *net = dev_net(dev);
 885
 886                 /* perhaps an address on the master device */
 887                 if (netif_is_l3_slave(dev)) {
 888                         struct net_device *mdev;
 889
 890                         mdev = netdev_master_upper_dev_get_rcu(dev);
 891                         if (mdev) {
 892                                 ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
 893                                 if (ifp)
 894                                         goto have_ifp;
 895                         }
 896                 }
 897
 898                 idev = in6_dev_get(dev);
 899                 if (!idev) {
 900                         /* XXX: count this drop? */
 901                         return reason;
 902                 }
 903
 904                 if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
 905                     (idev->cnf.forwarding &&
 906                      (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
 907                      (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
 908                         if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
 909                             skb->pkt_type != PACKET_HOST &&
 910                             inc &&
 911                             NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
 912                                 /*
 913                                  * for anycast or proxy,
 914                                  * sender should delay its response
 915                                  * by a random time between 0 and
 916                                  * MAX_ANYCAST_DELAY_TIME seconds.
 917                                  * (RFC2461) -- yoshfuji
 918                                  */
 919                                 struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
 920                                 if (n)
 921                                         pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
 922                                 goto out;
 923                         }
 924                 } else {
 925                         SKB_DR_SET(reason, IPV6_NDISC_NS_OTHERHOST);
 926                         goto out;
 927                 }
 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                 reason = SKB_CONSUMED;
 961         }
 962
 963 out:
 964         if (ifp)
 965                 in6_ifa_put(ifp);
 966         else
 967                 in6_dev_put(idev);
 968         return reason;
 969 }
 970
 971 static int accept_untracked_na(struct net_device *dev, struct in6_addr *saddr)
 972 {
 973         struct inet6_dev *idev = __in6_dev_get(dev);
 974
 975         switch (idev->cnf.accept_untracked_na) {
 976         case 0: /* Don't accept untracked na (absent in neighbor cache) */
 977                 return 0;
 978         case 1: /* Create new entries from na if currently untracked */
 979                 return 1;
 980         case 2: /* Create new entries from untracked na only if saddr is in the
 981                  * same subnet as an address configured on the interface that
 982                  * received the na
 983                  */
 984                 return !!ipv6_chk_prefix(saddr, dev);
 985         default:
 986                 return 0;
 987         }
 988 }
 989
 990 static enum skb_drop_reason ndisc_recv_na(struct sk_buff *skb)
 991 {
 992         struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
 993         struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
 994         const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
 995         u8 *lladdr = NULL;
 996         u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 997                                     offsetof(struct nd_msg, opt));
 998         struct ndisc_options ndopts;
 999         struct net_device *dev = skb->dev;
1000         struct inet6_dev *idev = __in6_dev_get(dev);
1001         struct inet6_ifaddr *ifp;
1002         struct neighbour *neigh;
1003         SKB_DR(reason);
1004         u8 new_state;
1005
1006         if (skb->len < sizeof(struct nd_msg))
1007                 return SKB_DROP_REASON_PKT_TOO_SMALL;
1008
1009         if (ipv6_addr_is_multicast(&msg->target)) {
1010                 ND_PRINTK(2, warn, "NA: target address is multicast\n");
1011                 return reason;
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 reason;
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 reason;
1028
1029         if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
1030                 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1031
1032         if (ndopts.nd_opts_tgt_lladdr) {
1033                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
1034                 if (!lladdr) {
1035                         ND_PRINTK(2, warn,
1036                                   "NA: invalid link-layer address length\n");
1037                         return reason;
1038                 }
1039         }
1040         ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
1041         if (ifp) {
1042                 if (skb->pkt_type != PACKET_LOOPBACK
1043                     && (ifp->flags & IFA_F_TENTATIVE)) {
1044                                 addrconf_dad_failure(skb, ifp);
1045                                 return reason;
1046                 }
1047                 /* What should we make now? The advertisement
1048                    is invalid, but ndisc specs say nothing
1049                    about it. It could be misconfiguration, or
1050                    an smart proxy agent tries to help us :-)
1051
1052                    We should not print the error if NA has been
1053                    received from loopback - it is just our own
1054                    unsolicited advertisement.
1055                  */
1056                 if (skb->pkt_type != PACKET_LOOPBACK)
1057                         ND_PRINTK(1, warn,
1058                                   "NA: %pM advertised our address %pI6c on %s!\n",
1059                                   eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
1060                 in6_ifa_put(ifp);
1061                 return reason;
1062         }
1063
1064         neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
1065
1066         /* RFC 9131 updates original Neighbour Discovery RFC 4861.
1067          * NAs with Target LL Address option without a corresponding
1068          * entry in the neighbour cache can now create a STALE neighbour
1069          * cache entry on routers.
1070          *
1071          *   entry accept  fwding  solicited        behaviour
1072          * ------- ------  ------  ---------    ----------------------
1073          * present      X       X         0     Set state to STALE
1074          * present      X       X         1     Set state to REACHABLE
1075          *  absent      0       X         X     Do nothing
1076          *  absent      1       0         X     Do nothing
1077          *  absent      1       1         X     Add a new STALE entry
1078          *
1079          * Note that we don't do a (daddr == all-routers-mcast) check.
1080          */
1081         new_state = msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE;
1082         if (!neigh && lladdr && idev && idev->cnf.forwarding) {
1083                 if (accept_untracked_na(dev, saddr)) {
1084                         neigh = neigh_create(&nd_tbl, &msg->target, dev);
1085                         new_state = NUD_STALE;
1086                 }
1087         }
1088
1089         if (neigh && !IS_ERR(neigh)) {
1090                 u8 old_flags = neigh->flags;
1091                 struct net *net = dev_net(dev);
1092
1093                 if (neigh->nud_state & NUD_FAILED)
1094                         goto out;
1095
1096                 /*
1097                  * Don't update the neighbor cache entry on a proxy NA from
1098                  * ourselves because either the proxied node is off link or it
1099                  * has already sent a NA to us.
1100                  */
1101                 if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
1102                     net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
1103                     pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
1104                         /* XXX: idev->cnf.proxy_ndp */
1105                         goto out;
1106                 }
1107
1108                 ndisc_update(dev, neigh, lladdr,
1109                              new_state,
1110                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1111                              (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
1112                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1113                              (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
1114                              NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
1115
1116                 if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
1117                         /*
1118                          * Change: router to host
1119                          */
1120                         rt6_clean_tohost(dev_net(dev),  saddr);
1121                 }
1122                 reason = SKB_CONSUMED;
1123 out:
1124                 neigh_release(neigh);
1125         }
1126         return reason;
1127 }
1128
1129 static enum skb_drop_reason 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         SKB_DR(reason);
1139
1140         if (skb->len < sizeof(*rs_msg))
1141                 return SKB_DROP_REASON_PKT_TOO_SMALL;
1142
1143         idev = __in6_dev_get(skb->dev);
1144         if (!idev) {
1145                 ND_PRINTK(1, err, "RS: can't find in6 device\n");
1146                 return reason;
1147         }
1148
1149         /* Don't accept RS if we're not in router mode */
1150         if (!idev->cnf.forwarding)
1151                 goto out;
1152
1153         /*
1154          * Don't update NCE if src = ::;
1155          * this implies that the source node has no ip address assigned yet.
1156          */
1157         if (ipv6_addr_any(saddr))
1158                 goto out;
1159
1160         /* Parse ND options */
1161         if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts))
1162                 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1163
1164         if (ndopts.nd_opts_src_lladdr) {
1165                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1166                                              skb->dev);
1167                 if (!lladdr)
1168                         goto out;
1169         }
1170
1171         neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
1172         if (neigh) {
1173                 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1174                              NEIGH_UPDATE_F_WEAK_OVERRIDE|
1175                              NEIGH_UPDATE_F_OVERRIDE|
1176                              NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
1177                              NDISC_ROUTER_SOLICITATION, &ndopts);
1178                 neigh_release(neigh);
1179                 reason = SKB_CONSUMED;
1180         }
1181 out:
1182         return reason;
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 enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
1232 {
1233         struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
1234         bool send_ifinfo_notify = false;
1235         struct neighbour *neigh = NULL;
1236         struct ndisc_options ndopts;
1237         struct fib6_info *rt = NULL;
1238         struct inet6_dev *in6_dev;
1239         u32 defrtr_usr_metric;
1240         unsigned int pref = 0;
1241         __u32 old_if_flags;
1242         struct net *net;
1243         SKB_DR(reason);
1244         int lifetime;
1245         int optlen;
1246
1247         __u8 *opt = (__u8 *)(ra_msg + 1);
1248
1249         optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
1250                 sizeof(struct ra_msg);
1251
1252         ND_PRINTK(2, info,
1253                   "RA: %s, dev: %s\n",
1254                   __func__, skb->dev->name);
1255         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1256                 ND_PRINTK(2, warn, "RA: source address is not link-local\n");
1257                 return reason;
1258         }
1259         if (optlen < 0)
1260                 return SKB_DROP_REASON_PKT_TOO_SMALL;
1261
1262 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1263         if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
1264                 ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
1265                 return reason;
1266         }
1267 #endif
1268
1269         /*
1270          *      set the RA_RECV flag in the interface
1271          */
1272
1273         in6_dev = __in6_dev_get(skb->dev);
1274         if (!in6_dev) {
1275                 ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
1276                           skb->dev->name);
1277                 return reason;
1278         }
1279
1280         if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts))
1281                 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1282
1283         if (!ipv6_accept_ra(in6_dev)) {
1284                 ND_PRINTK(2, info,
1285                           "RA: %s, did not accept ra for dev: %s\n",
1286                           __func__, skb->dev->name);
1287                 goto skip_linkparms;
1288         }
1289
1290 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1291         /* skip link-specific parameters from interior routers */
1292         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1293                 ND_PRINTK(2, info,
1294                           "RA: %s, nodetype is NODEFAULT, dev: %s\n",
1295                           __func__, skb->dev->name);
1296                 goto skip_linkparms;
1297         }
1298 #endif
1299
1300         if (in6_dev->if_flags & IF_RS_SENT) {
1301                 /*
1302                  *      flag that an RA was received after an RS was sent
1303                  *      out on this interface.
1304                  */
1305                 in6_dev->if_flags |= IF_RA_RCVD;
1306         }
1307
1308         /*
1309          * Remember the managed/otherconf flags from most recently
1310          * received RA message (RFC 2462) -- yoshfuji
1311          */
1312         old_if_flags = in6_dev->if_flags;
1313         in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
1314                                 IF_RA_OTHERCONF)) |
1315                                 (ra_msg->icmph.icmp6_addrconf_managed ?
1316                                         IF_RA_MANAGED : 0) |
1317                                 (ra_msg->icmph.icmp6_addrconf_other ?
1318                                         IF_RA_OTHERCONF : 0);
1319
1320         if (old_if_flags != in6_dev->if_flags)
1321                 send_ifinfo_notify = true;
1322
1323         if (!in6_dev->cnf.accept_ra_defrtr) {
1324                 ND_PRINTK(2, info,
1325                           "RA: %s, defrtr is false for dev: %s\n",
1326                           __func__, skb->dev->name);
1327                 goto skip_defrtr;
1328         }
1329
1330         /* Do not accept RA with source-addr found on local machine unless
1331          * accept_ra_from_local is set to true.
1332          */
1333         net = dev_net(in6_dev->dev);
1334         if (!in6_dev->cnf.accept_ra_from_local &&
1335             ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
1336                 ND_PRINTK(2, info,
1337                           "RA from local address detected on dev: %s: default router ignored\n",
1338                           skb->dev->name);
1339                 goto skip_defrtr;
1340         }
1341
1342         lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
1343
1344 #ifdef CONFIG_IPV6_ROUTER_PREF
1345         pref = ra_msg->icmph.icmp6_router_pref;
1346         /* 10b is handled as if it were 00b (medium) */
1347         if (pref == ICMPV6_ROUTER_PREF_INVALID ||
1348             !in6_dev->cnf.accept_ra_rtr_pref)
1349                 pref = ICMPV6_ROUTER_PREF_MEDIUM;
1350 #endif
1351         /* routes added from RAs do not use nexthop objects */
1352         rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
1353         if (rt) {
1354                 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1355                                          rt->fib6_nh->fib_nh_dev, NULL,
1356                                           &ipv6_hdr(skb)->saddr);
1357                 if (!neigh) {
1358                         ND_PRINTK(0, err,
1359                                   "RA: %s got default router without neighbour\n",
1360                                   __func__);
1361                         fib6_info_release(rt);
1362                         return reason;
1363                 }
1364         }
1365         /* Set default route metric as specified by user */
1366         defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
1367         /* delete the route if lifetime is 0 or if metric needs change */
1368         if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
1369                 ip6_del_rt(net, rt, false);
1370                 rt = NULL;
1371         }
1372
1373         ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, metric: %d, for dev: %s\n",
1374                   rt, lifetime, defrtr_usr_metric, skb->dev->name);
1375         if (!rt && lifetime) {
1376                 ND_PRINTK(3, info, "RA: adding default router\n");
1377
1378                 if (neigh)
1379                         neigh_release(neigh);
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 reason;
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 reason;
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                 reason = SKB_CONSUMED;
1486         }
1487
1488         if (!ipv6_accept_ra(in6_dev)) {
1489                 ND_PRINTK(2, info,
1490                           "RA: %s, accept_ra is false for dev: %s\n",
1491                           __func__, skb->dev->name);
1492                 goto out;
1493         }
1494
1495 #ifdef CONFIG_IPV6_ROUTE_INFO
1496         if (!in6_dev->cnf.accept_ra_from_local &&
1497             ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
1498                           in6_dev->dev, 0)) {
1499                 ND_PRINTK(2, info,
1500                           "RA from local address detected on dev: %s: router info ignored.\n",
1501                           skb->dev->name);
1502                 goto skip_routeinfo;
1503         }
1504
1505         if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
1506                 struct nd_opt_hdr *p;
1507                 for (p = ndopts.nd_opts_ri;
1508                      p;
1509                      p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
1510                         struct route_info *ri = (struct route_info *)p;
1511 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1512                         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
1513                             ri->prefix_len == 0)
1514                                 continue;
1515 #endif
1516                         if (ri->prefix_len == 0 &&
1517                             !in6_dev->cnf.accept_ra_defrtr)
1518                                 continue;
1519                         if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
1520                                 continue;
1521                         if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
1522                                 continue;
1523                         rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
1524                                       &ipv6_hdr(skb)->saddr);
1525                 }
1526         }
1527
1528 skip_routeinfo:
1529 #endif
1530
1531 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1532         /* skip link-specific ndopts from interior routers */
1533         if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1534                 ND_PRINTK(2, info,
1535                           "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
1536                           __func__, skb->dev->name);
1537                 goto out;
1538         }
1539 #endif
1540
1541         if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
1542                 struct nd_opt_hdr *p;
1543                 for (p = ndopts.nd_opts_pi;
1544                      p;
1545                      p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
1546                         addrconf_prefix_rcv(skb->dev, (u8 *)p,
1547                                             (p->nd_opt_len) << 3,
1548                                             ndopts.nd_opts_src_lladdr != NULL);
1549                 }
1550         }
1551
1552         if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
1553                 __be32 n;
1554                 u32 mtu;
1555
1556                 memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
1557                 mtu = ntohl(n);
1558
1559                 if (in6_dev->ra_mtu != mtu) {
1560                         in6_dev->ra_mtu = mtu;
1561                         send_ifinfo_notify = true;
1562                 }
1563
1564                 if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
1565                         ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
1566                 } else if (in6_dev->cnf.mtu6 != mtu) {
1567                         in6_dev->cnf.mtu6 = mtu;
1568                         fib6_metric_set(rt, RTAX_MTU, mtu);
1569                         rt6_mtu_change(skb->dev, mtu);
1570                 }
1571         }
1572
1573         if (ndopts.nd_useropts) {
1574                 struct nd_opt_hdr *p;
1575                 for (p = ndopts.nd_useropts;
1576                      p;
1577                      p = ndisc_next_useropt(skb->dev, p,
1578                                             ndopts.nd_useropts_end)) {
1579                         ndisc_ra_useropt(skb, p);
1580                 }
1581         }
1582
1583         if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
1584                 ND_PRINTK(2, warn, "RA: invalid RA options\n");
1585         }
1586 out:
1587         /* Send a notify if RA changed managed/otherconf flags or
1588          * timer settings or ra_mtu value
1589          */
1590         if (send_ifinfo_notify)
1591                 inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
1592
1593         fib6_info_release(rt);
1594         if (neigh)
1595                 neigh_release(neigh);
1596         return reason;
1597 }
1598
1599 static enum skb_drop_reason ndisc_redirect_rcv(struct sk_buff *skb)
1600 {
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         struct ndisc_options ndopts;
1605         SKB_DR(reason);
1606         u8 *hdr;
1607
1608 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1609         switch (skb->ndisc_nodetype) {
1610         case NDISC_NODETYPE_HOST:
1611         case NDISC_NODETYPE_NODEFAULT:
1612                 ND_PRINTK(2, warn,
1613                           "Redirect: from host or unauthorized router\n");
1614                 return reason;
1615         }
1616 #endif
1617
1618         if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1619                 ND_PRINTK(2, warn,
1620                           "Redirect: source address is not link-local\n");
1621                 return reason;
1622         }
1623
1624         if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
1625                 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1626
1627         if (!ndopts.nd_opts_rh) {
1628                 ip6_redirect_no_header(skb, dev_net(skb->dev),
1629                                         skb->dev->ifindex);
1630                 return reason;
1631         }
1632
1633         hdr = (u8 *)ndopts.nd_opts_rh;
1634         hdr += 8;
1635         if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
1636                 return SKB_DROP_REASON_PKT_TOO_SMALL;
1637
1638         return icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
1639 }
1640
1641 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
1642                                            struct sk_buff *orig_skb,
1643                                            int rd_len)
1644 {
1645         u8 *opt = skb_put(skb, rd_len);
1646
1647         memset(opt, 0, 8);
1648         *(opt++) = ND_OPT_REDIRECT_HDR;
1649         *(opt++) = (rd_len >> 3);
1650         opt += 6;
1651
1652         skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
1653                       rd_len - 8);
1654 }
1655
1656 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
1657 {
1658         struct net_device *dev = skb->dev;
1659         struct net *net = dev_net(dev);
1660         struct sock *sk = net->ipv6.ndisc_sk;
1661         int optlen = 0;
1662         struct inet_peer *peer;
1663         struct sk_buff *buff;
1664         struct rd_msg *msg;
1665         struct in6_addr saddr_buf;
1666         struct rt6_info *rt;
1667         struct dst_entry *dst;
1668         struct flowi6 fl6;
1669         int rd_len;
1670         u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
1671            ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
1672         bool ret;
1673
1674         if (netif_is_l3_master(skb->dev)) {
1675                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
1676                 if (!dev)
1677                         return;
1678         }
1679
1680         if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
1681                 ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
1682                           dev->name);
1683                 return;
1684         }
1685
1686         if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
1687             ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
1688                 ND_PRINTK(2, warn,
1689                           "Redirect: target address is not link-local unicast\n");
1690                 return;
1691         }
1692
1693         icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
1694                          &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
1695
1696         dst = ip6_route_output(net, NULL, &fl6);
1697         if (dst->error) {
1698                 dst_release(dst);
1699                 return;
1700         }
1701         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
1702         if (IS_ERR(dst))
1703                 return;
1704
1705         rt = (struct rt6_info *) dst;
1706
1707         if (rt->rt6i_flags & RTF_GATEWAY) {
1708                 ND_PRINTK(2, warn,
1709                           "Redirect: destination is not a neighbour\n");
1710                 goto release;
1711         }
1712         peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
1713         ret = inet_peer_xrlim_allow(peer, 1*HZ);
1714         if (peer)
1715                 inet_putpeer(peer);
1716         if (!ret)
1717                 goto release;
1718
1719         if (dev->addr_len) {
1720                 struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
1721                 if (!neigh) {
1722                         ND_PRINTK(2, warn,
1723                                   "Redirect: no neigh for target address\n");
1724                         goto release;
1725                 }
1726
1727                 read_lock_bh(&neigh->lock);
1728                 if (neigh->nud_state & NUD_VALID) {
1729                         memcpy(ha_buf, neigh->ha, dev->addr_len);
1730                         read_unlock_bh(&neigh->lock);
1731                         ha = ha_buf;
1732                         optlen += ndisc_redirect_opt_addr_space(dev, neigh,
1733                                                                 ops_data_buf,
1734                                                                 &ops_data);
1735                 } else
1736                         read_unlock_bh(&neigh->lock);
1737
1738                 neigh_release(neigh);
1739         }
1740
1741         rd_len = min_t(unsigned int,
1742                        IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
1743                        skb->len + 8);
1744         rd_len &= ~0x7;
1745         optlen += rd_len;
1746
1747         buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
1748         if (!buff)
1749                 goto release;
1750
1751         msg = skb_put(buff, sizeof(*msg));
1752         *msg = (struct rd_msg) {
1753                 .icmph = {
1754                         .icmp6_type = NDISC_REDIRECT,
1755                 },
1756                 .target = *target,
1757                 .dest = ipv6_hdr(skb)->daddr,
1758         };
1759
1760         /*
1761          *      include target_address option
1762          */
1763
1764         if (ha)
1765                 ndisc_fill_redirect_addr_option(buff, ha, ops_data);
1766
1767         /*
1768          *      build redirect option and copy skb over to the new packet.
1769          */
1770
1771         if (rd_len)
1772                 ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
1773
1774         skb_dst_set(buff, dst);
1775         ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
1776         return;
1777
1778 release:
1779         dst_release(dst);
1780 }
1781
1782 static void pndisc_redo(struct sk_buff *skb)
1783 {
1784         enum skb_drop_reason reason = ndisc_recv_ns(skb);
1785
1786         kfree_skb_reason(skb, reason);
1787 }
1788
1789 static int ndisc_is_multicast(const void *pkey)
1790 {
1791         return ipv6_addr_is_multicast((struct in6_addr *)pkey);
1792 }
1793
1794 static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
1795 {
1796         struct inet6_dev *idev = __in6_dev_get(skb->dev);
1797
1798         if (!idev)
1799                 return true;
1800         if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
1801             idev->cnf.suppress_frag_ndisc) {
1802                 net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
1803                 return true;
1804         }
1805         return false;
1806 }
1807
1808 enum skb_drop_reason ndisc_rcv(struct sk_buff *skb)
1809 {
1810         struct nd_msg *msg;
1811         SKB_DR(reason);
1812
1813         if (ndisc_suppress_frag_ndisc(skb))
1814                 return SKB_DROP_REASON_IPV6_NDISC_FRAG;
1815
1816         if (skb_linearize(skb))
1817                 return SKB_DROP_REASON_NOMEM;
1818
1819         msg = (struct nd_msg *)skb_transport_header(skb);
1820
1821         __skb_push(skb, skb->data - skb_transport_header(skb));
1822
1823         if (ipv6_hdr(skb)->hop_limit != 255) {
1824                 ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
1825                           ipv6_hdr(skb)->hop_limit);
1826                 return SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT;
1827         }
1828
1829         if (msg->icmph.icmp6_code != 0) {
1830                 ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
1831                           msg->icmph.icmp6_code);
1832                 return SKB_DROP_REASON_IPV6_NDISC_BAD_CODE;
1833         }
1834
1835         switch (msg->icmph.icmp6_type) {
1836         case NDISC_NEIGHBOUR_SOLICITATION:
1837                 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
1838                 reason = ndisc_recv_ns(skb);
1839                 break;
1840
1841         case NDISC_NEIGHBOUR_ADVERTISEMENT:
1842                 reason = ndisc_recv_na(skb);
1843                 break;
1844
1845         case NDISC_ROUTER_SOLICITATION:
1846                 reason = ndisc_recv_rs(skb);
1847                 break;
1848
1849         case NDISC_ROUTER_ADVERTISEMENT:
1850                 reason = ndisc_router_discovery(skb);
1851                 break;
1852
1853         case NDISC_REDIRECT:
1854                 reason = ndisc_redirect_rcv(skb);
1855                 break;
1856         }
1857
1858         return reason;
1859 }
1860
1861 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1862 {
1863         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1864         struct netdev_notifier_change_info *change_info;
1865         struct net *net = dev_net(dev);
1866         struct inet6_dev *idev;
1867         bool evict_nocarrier;
1868
1869         switch (event) {
1870         case NETDEV_CHANGEADDR:
1871                 neigh_changeaddr(&nd_tbl, dev);
1872                 fib6_run_gc(0, net, false);
1873                 fallthrough;
1874         case NETDEV_UP:
1875                 idev = in6_dev_get(dev);
1876                 if (!idev)
1877                         break;
1878                 if (idev->cnf.ndisc_notify ||
1879                     net->ipv6.devconf_all->ndisc_notify)
1880                         ndisc_send_unsol_na(dev);
1881                 in6_dev_put(idev);
1882                 break;
1883         case NETDEV_CHANGE:
1884                 idev = in6_dev_get(dev);
1885                 if (!idev)
1886                         evict_nocarrier = true;
1887                 else {
1888                         evict_nocarrier = idev->cnf.ndisc_evict_nocarrier &&
1889                                           net->ipv6.devconf_all->ndisc_evict_nocarrier;
1890                         in6_dev_put(idev);
1891                 }
1892
1893                 change_info = ptr;
1894                 if (change_info->flags_changed & IFF_NOARP)
1895                         neigh_changeaddr(&nd_tbl, dev);
1896                 if (evict_nocarrier && !netif_carrier_ok(dev))
1897                         neigh_carrier_down(&nd_tbl, dev);
1898                 break;
1899         case NETDEV_DOWN:
1900                 neigh_ifdown(&nd_tbl, dev);
1901                 fib6_run_gc(0, net, false);
1902                 break;
1903         case NETDEV_NOTIFY_PEERS:
1904                 ndisc_send_unsol_na(dev);
1905                 break;
1906         default:
1907                 break;
1908         }
1909
1910         return NOTIFY_DONE;
1911 }
1912
1913 static struct notifier_block ndisc_netdev_notifier = {
1914         .notifier_call = ndisc_netdev_event,
1915         .priority = ADDRCONF_NOTIFY_PRIORITY - 5,
1916 };
1917
1918 #ifdef CONFIG_SYSCTL
1919 static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
1920                                          const char *func, const char *dev_name)
1921 {
1922         static char warncomm[TASK_COMM_LEN];
1923         static int warned;
1924         if (strcmp(warncomm, current->comm) && warned < 5) {
1925                 strcpy(warncomm, current->comm);
1926                 pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
1927                         warncomm, func,
1928                         dev_name, ctl->procname,
1929                         dev_name, ctl->procname);
1930                 warned++;
1931         }
1932 }
1933
1934 int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
1935                 size_t *lenp, loff_t *ppos)
1936 {
1937         struct net_device *dev = ctl->extra1;
1938         struct inet6_dev *idev;
1939         int ret;
1940
1941         if ((strcmp(ctl->procname, "retrans_time") == 0) ||
1942             (strcmp(ctl->procname, "base_reachable_time") == 0))
1943                 ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
1944
1945         if (strcmp(ctl->procname, "retrans_time") == 0)
1946                 ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
1947
1948         else if (strcmp(ctl->procname, "base_reachable_time") == 0)
1949                 ret = neigh_proc_dointvec_jiffies(ctl, write,
1950                                                   buffer, lenp, ppos);
1951
1952         else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
1953                  (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
1954                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
1955                                                      buffer, lenp, ppos);
1956         else
1957                 ret = -1;
1958
1959         if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
1960                 if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
1961                         idev->nd_parms->reachable_time =
1962                                         neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
1963                 idev->tstamp = jiffies;
1964                 inet6_ifinfo_notify(RTM_NEWLINK, idev);
1965                 in6_dev_put(idev);
1966         }
1967         return ret;
1968 }
1969
1970
1971 #endif
1972
1973 static int __net_init ndisc_net_init(struct net *net)
1974 {
1975         struct ipv6_pinfo *np;
1976         struct sock *sk;
1977         int err;
1978
1979         err = inet_ctl_sock_create(&sk, PF_INET6,
1980                                    SOCK_RAW, IPPROTO_ICMPV6, net);
1981         if (err < 0) {
1982                 ND_PRINTK(0, err,
1983                           "NDISC: Failed to initialize the control socket (err %d)\n",
1984                           err);
1985                 return err;
1986         }
1987
1988         net->ipv6.ndisc_sk = sk;
1989
1990         np = inet6_sk(sk);
1991         np->hop_limit = 255;
1992         /* Do not loopback ndisc messages */
1993         np->mc_loop = 0;
1994
1995         return 0;
1996 }
1997
1998 static void __net_exit ndisc_net_exit(struct net *net)
1999 {
2000         inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
2001 }
2002
2003 static struct pernet_operations ndisc_net_ops = {
2004         .init = ndisc_net_init,
2005         .exit = ndisc_net_exit,
2006 };
2007
2008 int __init ndisc_init(void)
2009 {
2010         int err;
2011
2012         err = register_pernet_subsys(&ndisc_net_ops);
2013         if (err)
2014                 return err;
2015         /*
2016          * Initialize the neighbour table
2017          */
2018         neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
2019
2020 #ifdef CONFIG_SYSCTL
2021         err = neigh_sysctl_register(NULL, &nd_tbl.parms,
2022                                     ndisc_ifinfo_sysctl_change);
2023         if (err)
2024                 goto out_unregister_pernet;
2025 out:
2026 #endif
2027         return err;
2028
2029 #ifdef CONFIG_SYSCTL
2030 out_unregister_pernet:
2031         unregister_pernet_subsys(&ndisc_net_ops);
2032         goto out;
2033 #endif
2034 }
2035
2036 int __init ndisc_late_init(void)
2037 {
2038         return register_netdevice_notifier(&ndisc_netdev_notifier);
2039 }
2040
2041 void ndisc_late_cleanup(void)
2042 {
2043         unregister_netdevice_notifier(&ndisc_netdev_notifier);
2044 }
2045
2046 void ndisc_cleanup(void)
2047 {
2048 #ifdef CONFIG_SYSCTL
2049         neigh_sysctl_unregister(&nd_tbl.parms);
2050 #endif
2051         neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
2052         unregister_pernet_subsys(&ndisc_net_ops);
2053 }