net/ipv4/fib_semantics.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              IPv4 Forwarding Information Base: semantics.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/uaccess.h>
  13 #include <linux/bitops.h>
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/mm.h>
  18 #include <linux/string.h>
  19 #include <linux/socket.h>
  20 #include <linux/sockios.h>
  21 #include <linux/errno.h>
  22 #include <linux/in.h>
  23 #include <linux/inet.h>
  24 #include <linux/inetdevice.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/init.h>
  30 #include <linux/slab.h>
  31 #include <linux/netlink.h>
  32
  33 #include <net/arp.h>
  34 #include <net/ip.h>
  35 #include <net/protocol.h>
  36 #include <net/route.h>
  37 #include <net/tcp.h>
  38 #include <net/sock.h>
  39 #include <net/ip_fib.h>
  40 #include <net/ip6_fib.h>
  41 #include <net/nexthop.h>
  42 #include <net/netlink.h>
  43 #include <net/rtnh.h>
  44 #include <net/lwtunnel.h>
  45 #include <net/fib_notifier.h>
  46 #include <net/addrconf.h>
  47
  48 #include "fib_lookup.h"
  49
  50 static DEFINE_SPINLOCK(fib_info_lock);
  51 static struct hlist_head *fib_info_hash;
  52 static struct hlist_head *fib_info_laddrhash;
  53 static unsigned int fib_info_hash_size;
  54 static unsigned int fib_info_cnt;
  55
  56 #define DEVINDEX_HASHBITS 8
  57 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  58 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  59
  60 /* for_nexthops and change_nexthops only used when nexthop object
  61  * is not set in a fib_info. The logic within can reference fib_nh.
  62  */
  63 #ifdef CONFIG_IP_ROUTE_MULTIPATH
  64
  65 #define for_nexthops(fi) {                                              \
  66         int nhsel; const struct fib_nh *nh;                             \
  67         for (nhsel = 0, nh = (fi)->fib_nh;                              \
  68              nhsel < fib_info_num_path((fi));                           \
  69              nh++, nhsel++)
  70
  71 #define change_nexthops(fi) {                                           \
  72         int nhsel; struct fib_nh *nexthop_nh;                           \
  73         for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh);   \
  74              nhsel < fib_info_num_path((fi));                           \
  75              nexthop_nh++, nhsel++)
  76
  77 #else /* CONFIG_IP_ROUTE_MULTIPATH */
  78
  79 /* Hope, that gcc will optimize it to get rid of dummy loop */
  80
  81 #define for_nexthops(fi) {                                              \
  82         int nhsel; const struct fib_nh *nh = (fi)->fib_nh;              \
  83         for (nhsel = 0; nhsel < 1; nhsel++)
  84
  85 #define change_nexthops(fi) {                                           \
  86         int nhsel;                                                      \
  87         struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);    \
  88         for (nhsel = 0; nhsel < 1; nhsel++)
  89
  90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
  91
  92 #define endfor_nexthops(fi) }
  93
  94
  95 const struct fib_prop fib_props[RTN_MAX + 1] = {
  96         [RTN_UNSPEC] = {
  97                 .error  = 0,
  98                 .scope  = RT_SCOPE_NOWHERE,
  99         },
 100         [RTN_UNICAST] = {
 101                 .error  = 0,
 102                 .scope  = RT_SCOPE_UNIVERSE,
 103         },
 104         [RTN_LOCAL] = {
 105                 .error  = 0,
 106                 .scope  = RT_SCOPE_HOST,
 107         },
 108         [RTN_BROADCAST] = {
 109                 .error  = 0,
 110                 .scope  = RT_SCOPE_LINK,
 111         },
 112         [RTN_ANYCAST] = {
 113                 .error  = 0,
 114                 .scope  = RT_SCOPE_LINK,
 115         },
 116         [RTN_MULTICAST] = {
 117                 .error  = 0,
 118                 .scope  = RT_SCOPE_UNIVERSE,
 119         },
 120         [RTN_BLACKHOLE] = {
 121                 .error  = -EINVAL,
 122                 .scope  = RT_SCOPE_UNIVERSE,
 123         },
 124         [RTN_UNREACHABLE] = {
 125                 .error  = -EHOSTUNREACH,
 126                 .scope  = RT_SCOPE_UNIVERSE,
 127         },
 128         [RTN_PROHIBIT] = {
 129                 .error  = -EACCES,
 130                 .scope  = RT_SCOPE_UNIVERSE,
 131         },
 132         [RTN_THROW] = {
 133                 .error  = -EAGAIN,
 134                 .scope  = RT_SCOPE_UNIVERSE,
 135         },
 136         [RTN_NAT] = {
 137                 .error  = -EINVAL,
 138                 .scope  = RT_SCOPE_NOWHERE,
 139         },
 140         [RTN_XRESOLVE] = {
 141                 .error  = -EINVAL,
 142                 .scope  = RT_SCOPE_NOWHERE,
 143         },
 144 };
 145
 146 static void rt_fibinfo_free(struct rtable __rcu **rtp)
 147 {
 148         struct rtable *rt = rcu_dereference_protected(*rtp, 1);
 149
 150         if (!rt)
 151                 return;
 152
 153         /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
 154          * because we waited an RCU grace period before calling
 155          * free_fib_info_rcu()
 156          */
 157
 158         dst_dev_put(&rt->dst);
 159         dst_release_immediate(&rt->dst);
 160 }
 161
 162 static void free_nh_exceptions(struct fib_nh_common *nhc)
 163 {
 164         struct fnhe_hash_bucket *hash;
 165         int i;
 166
 167         hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
 168         if (!hash)
 169                 return;
 170         for (i = 0; i < FNHE_HASH_SIZE; i++) {
 171                 struct fib_nh_exception *fnhe;
 172
 173                 fnhe = rcu_dereference_protected(hash[i].chain, 1);
 174                 while (fnhe) {
 175                         struct fib_nh_exception *next;
 176
 177                         next = rcu_dereference_protected(fnhe->fnhe_next, 1);
 178
 179                         rt_fibinfo_free(&fnhe->fnhe_rth_input);
 180                         rt_fibinfo_free(&fnhe->fnhe_rth_output);
 181
 182                         kfree(fnhe);
 183
 184                         fnhe = next;
 185                 }
 186         }
 187         kfree(hash);
 188 }
 189
 190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 191 {
 192         int cpu;
 193
 194         if (!rtp)
 195                 return;
 196
 197         for_each_possible_cpu(cpu) {
 198                 struct rtable *rt;
 199
 200                 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
 201                 if (rt) {
 202                         dst_dev_put(&rt->dst);
 203                         dst_release_immediate(&rt->dst);
 204                 }
 205         }
 206         free_percpu(rtp);
 207 }
 208
 209 void fib_nh_common_release(struct fib_nh_common *nhc)
 210 {
 211         if (nhc->nhc_dev)
 212                 dev_put(nhc->nhc_dev);
 213
 214         lwtstate_put(nhc->nhc_lwtstate);
 215         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 216         rt_fibinfo_free(&nhc->nhc_rth_input);
 217         free_nh_exceptions(nhc);
 218 }
 219 EXPORT_SYMBOL_GPL(fib_nh_common_release);
 220
 221 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 222 {
 223 #ifdef CONFIG_IP_ROUTE_CLASSID
 224         if (fib_nh->nh_tclassid)
 225                 net->ipv4.fib_num_tclassid_users--;
 226 #endif
 227         fib_nh_common_release(&fib_nh->nh_common);
 228 }
 229
 230 /* Release a nexthop info record */
 231 static void free_fib_info_rcu(struct rcu_head *head)
 232 {
 233         struct fib_info *fi = container_of(head, struct fib_info, rcu);
 234
 235         if (fi->nh) {
 236                 nexthop_put(fi->nh);
 237         } else {
 238                 change_nexthops(fi) {
 239                         fib_nh_release(fi->fib_net, nexthop_nh);
 240                 } endfor_nexthops(fi);
 241         }
 242
 243         ip_fib_metrics_put(fi->fib_metrics);
 244
 245         kfree(fi);
 246 }
 247
 248 void free_fib_info(struct fib_info *fi)
 249 {
 250         if (fi->fib_dead == 0) {
 251                 pr_warn("Freeing alive fib_info %p\n", fi);
 252                 return;
 253         }
 254         fib_info_cnt--;
 255
 256         call_rcu(&fi->rcu, free_fib_info_rcu);
 257 }
 258 EXPORT_SYMBOL_GPL(free_fib_info);
 259
 260 void fib_release_info(struct fib_info *fi)
 261 {
 262         spin_lock_bh(&fib_info_lock);
 263         if (fi && --fi->fib_treeref == 0) {
 264                 hlist_del(&fi->fib_hash);
 265                 if (fi->fib_prefsrc)
 266                         hlist_del(&fi->fib_lhash);
 267                 if (fi->nh) {
 268                         list_del(&fi->nh_list);
 269                 } else {
 270                         change_nexthops(fi) {
 271                                 if (!nexthop_nh->fib_nh_dev)
 272                                         continue;
 273                                 hlist_del(&nexthop_nh->nh_hash);
 274                         } endfor_nexthops(fi)
 275                 }
 276                 fi->fib_dead = 1;
 277                 fib_info_put(fi);
 278         }
 279         spin_unlock_bh(&fib_info_lock);
 280 }
 281
 282 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
 283 {
 284         const struct fib_nh *onh;
 285
 286         if (fi->nh || ofi->nh)
 287                 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
 288
 289         if (ofi->fib_nhs == 0)
 290                 return 0;
 291
 292         for_nexthops(fi) {
 293                 onh = fib_info_nh(ofi, nhsel);
 294
 295                 if (nh->fib_nh_oif != onh->fib_nh_oif ||
 296                     nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
 297                     nh->fib_nh_scope != onh->fib_nh_scope ||
 298 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 299                     nh->fib_nh_weight != onh->fib_nh_weight ||
 300 #endif
 301 #ifdef CONFIG_IP_ROUTE_CLASSID
 302                     nh->nh_tclassid != onh->nh_tclassid ||
 303 #endif
 304                     lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
 305                     ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
 306                         return -1;
 307
 308                 if (nh->fib_nh_gw_family == AF_INET &&
 309                     nh->fib_nh_gw4 != onh->fib_nh_gw4)
 310                         return -1;
 311
 312                 if (nh->fib_nh_gw_family == AF_INET6 &&
 313                     ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
 314                         return -1;
 315         } endfor_nexthops(fi);
 316         return 0;
 317 }
 318
 319 static inline unsigned int fib_devindex_hashfn(unsigned int val)
 320 {
 321         unsigned int mask = DEVINDEX_HASHSIZE - 1;
 322
 323         return (val ^
 324                 (val >> DEVINDEX_HASHBITS) ^
 325                 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
 326 }
 327
 328 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
 329                                       u32 prefsrc, u32 priority)
 330 {
 331         unsigned int val = init_val;
 332
 333         val ^= (protocol << 8) | scope;
 334         val ^= prefsrc;
 335         val ^= priority;
 336
 337         return val;
 338 }
 339
 340 static unsigned int fib_info_hashfn_result(unsigned int val)
 341 {
 342         unsigned int mask = (fib_info_hash_size - 1);
 343
 344         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 345 }
 346
 347 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 348 {
 349         unsigned int val;
 350
 351         val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
 352                                 fi->fib_scope, (__force u32)fi->fib_prefsrc,
 353                                 fi->fib_priority);
 354
 355         if (fi->nh) {
 356                 val ^= fib_devindex_hashfn(fi->nh->id);
 357         } else {
 358                 for_nexthops(fi) {
 359                         val ^= fib_devindex_hashfn(nh->fib_nh_oif);
 360                 } endfor_nexthops(fi)
 361         }
 362
 363         return fib_info_hashfn_result(val);
 364 }
 365
 366 /* no metrics, only nexthop id */
 367 static struct fib_info *fib_find_info_nh(struct net *net,
 368                                          const struct fib_config *cfg)
 369 {
 370         struct hlist_head *head;
 371         struct fib_info *fi;
 372         unsigned int hash;
 373
 374         hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
 375                                  cfg->fc_protocol, cfg->fc_scope,
 376                                  (__force u32)cfg->fc_prefsrc,
 377                                  cfg->fc_priority);
 378         hash = fib_info_hashfn_result(hash);
 379         head = &fib_info_hash[hash];
 380
 381         hlist_for_each_entry(fi, head, fib_hash) {
 382                 if (!net_eq(fi->fib_net, net))
 383                         continue;
 384                 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
 385                         continue;
 386                 if (cfg->fc_protocol == fi->fib_protocol &&
 387                     cfg->fc_scope == fi->fib_scope &&
 388                     cfg->fc_prefsrc == fi->fib_prefsrc &&
 389                     cfg->fc_priority == fi->fib_priority &&
 390                     cfg->fc_type == fi->fib_type &&
 391                     cfg->fc_table == fi->fib_tb_id &&
 392                     !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
 393                         return fi;
 394         }
 395
 396         return NULL;
 397 }
 398
 399 static struct fib_info *fib_find_info(struct fib_info *nfi)
 400 {
 401         struct hlist_head *head;
 402         struct fib_info *fi;
 403         unsigned int hash;
 404
 405         hash = fib_info_hashfn(nfi);
 406         head = &fib_info_hash[hash];
 407
 408         hlist_for_each_entry(fi, head, fib_hash) {
 409                 if (!net_eq(fi->fib_net, nfi->fib_net))
 410                         continue;
 411                 if (fi->fib_nhs != nfi->fib_nhs)
 412                         continue;
 413                 if (nfi->fib_protocol == fi->fib_protocol &&
 414                     nfi->fib_scope == fi->fib_scope &&
 415                     nfi->fib_prefsrc == fi->fib_prefsrc &&
 416                     nfi->fib_priority == fi->fib_priority &&
 417                     nfi->fib_type == fi->fib_type &&
 418                     memcmp(nfi->fib_metrics, fi->fib_metrics,
 419                            sizeof(u32) * RTAX_MAX) == 0 &&
 420                     !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 421                     nh_comp(fi, nfi) == 0)
 422                         return fi;
 423         }
 424
 425         return NULL;
 426 }
 427
 428 /* Check, that the gateway is already configured.
 429  * Used only by redirect accept routine.
 430  */
 431 int ip_fib_check_default(__be32 gw, struct net_device *dev)
 432 {
 433         struct hlist_head *head;
 434         struct fib_nh *nh;
 435         unsigned int hash;
 436
 437         spin_lock(&fib_info_lock);
 438
 439         hash = fib_devindex_hashfn(dev->ifindex);
 440         head = &fib_info_devhash[hash];
 441         hlist_for_each_entry(nh, head, nh_hash) {
 442                 if (nh->fib_nh_dev == dev &&
 443                     nh->fib_nh_gw4 == gw &&
 444                     !(nh->fib_nh_flags & RTNH_F_DEAD)) {
 445                         spin_unlock(&fib_info_lock);
 446                         return 0;
 447                 }
 448         }
 449
 450         spin_unlock(&fib_info_lock);
 451
 452         return -1;
 453 }
 454
 455 static inline size_t fib_nlmsg_size(struct fib_info *fi)
 456 {
 457         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 458                          + nla_total_size(4) /* RTA_TABLE */
 459                          + nla_total_size(4) /* RTA_DST */
 460                          + nla_total_size(4) /* RTA_PRIORITY */
 461                          + nla_total_size(4) /* RTA_PREFSRC */
 462                          + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 463         unsigned int nhs = fib_info_num_path(fi);
 464
 465         /* space for nested metrics */
 466         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 467
 468         if (fi->nh)
 469                 payload += nla_total_size(4); /* RTA_NH_ID */
 470
 471         if (nhs) {
 472                 size_t nh_encapsize = 0;
 473                 /* Also handles the special case nhs == 1 */
 474
 475                 /* each nexthop is packed in an attribute */
 476                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 477                 unsigned int i;
 478
 479                 /* may contain flow and gateway attribute */
 480                 nhsize += 2 * nla_total_size(4);
 481
 482                 /* grab encap info */
 483                 for (i = 0; i < fib_info_num_path(fi); i++) {
 484                         struct fib_nh_common *nhc = fib_info_nhc(fi, i);
 485
 486                         if (nhc->nhc_lwtstate) {
 487                                 /* RTA_ENCAP_TYPE */
 488                                 nh_encapsize += lwtunnel_get_encap_size(
 489                                                 nhc->nhc_lwtstate);
 490                                 /* RTA_ENCAP */
 491                                 nh_encapsize +=  nla_total_size(2);
 492                         }
 493                 }
 494
 495                 /* all nexthops are packed in a nested attribute */
 496                 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
 497
 498         }
 499
 500         return payload;
 501 }
 502
 503 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 504                int dst_len, u32 tb_id, const struct nl_info *info,
 505                unsigned int nlm_flags)
 506 {
 507         struct sk_buff *skb;
 508         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 509         int err = -ENOBUFS;
 510
 511         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 512         if (!skb)
 513                 goto errout;
 514
 515         err = fib_dump_info(skb, info->portid, seq, event, tb_id,
 516                             fa->fa_type, key, dst_len,
 517                             fa->fa_tos, fa->fa_info, nlm_flags);
 518         if (err < 0) {
 519                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 520                 WARN_ON(err == -EMSGSIZE);
 521                 kfree_skb(skb);
 522                 goto errout;
 523         }
 524         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 525                     info->nlh, GFP_KERNEL);
 526         return;
 527 errout:
 528         if (err < 0)
 529                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 530 }
 531
 532 static int fib_detect_death(struct fib_info *fi, int order,
 533                             struct fib_info **last_resort, int *last_idx,
 534                             int dflt)
 535 {
 536         const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 537         struct neighbour *n;
 538         int state = NUD_NONE;
 539
 540         if (likely(nhc->nhc_gw_family == AF_INET))
 541                 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 542         else if (nhc->nhc_gw_family == AF_INET6)
 543                 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 544                                  nhc->nhc_dev);
 545         else
 546                 n = NULL;
 547
 548         if (n) {
 549                 state = n->nud_state;
 550                 neigh_release(n);
 551         } else {
 552                 return 0;
 553         }
 554         if (state == NUD_REACHABLE)
 555                 return 0;
 556         if ((state & NUD_VALID) && order != dflt)
 557                 return 0;
 558         if ((state & NUD_VALID) ||
 559             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 560                 *last_resort = fi;
 561                 *last_idx = order;
 562         }
 563         return 1;
 564 }
 565
 566 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap,
 567                        u16 encap_type, void *cfg, gfp_t gfp_flags,
 568                        struct netlink_ext_ack *extack)
 569 {
 570         int err;
 571
 572         nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 573                                                     gfp_flags);
 574         if (!nhc->nhc_pcpu_rth_output)
 575                 return -ENOMEM;
 576
 577         if (encap) {
 578                 struct lwtunnel_state *lwtstate;
 579
 580                 if (encap_type == LWTUNNEL_ENCAP_NONE) {
 581                         NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 582                         err = -EINVAL;
 583                         goto lwt_failure;
 584                 }
 585                 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family,
 586                                            cfg, &lwtstate, extack);
 587                 if (err)
 588                         goto lwt_failure;
 589
 590                 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 591         }
 592
 593         return 0;
 594
 595 lwt_failure:
 596         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 597         nhc->nhc_pcpu_rth_output = NULL;
 598         return err;
 599 }
 600 EXPORT_SYMBOL_GPL(fib_nh_common_init);
 601
 602 int fib_nh_init(struct net *net, struct fib_nh *nh,
 603                 struct fib_config *cfg, int nh_weight,
 604                 struct netlink_ext_ack *extack)
 605 {
 606         int err;
 607
 608         nh->fib_nh_family = AF_INET;
 609
 610         err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap,
 611                                  cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 612         if (err)
 613                 return err;
 614
 615         nh->fib_nh_oif = cfg->fc_oif;
 616         nh->fib_nh_gw_family = cfg->fc_gw_family;
 617         if (cfg->fc_gw_family == AF_INET)
 618                 nh->fib_nh_gw4 = cfg->fc_gw4;
 619         else if (cfg->fc_gw_family == AF_INET6)
 620                 nh->fib_nh_gw6 = cfg->fc_gw6;
 621
 622         nh->fib_nh_flags = cfg->fc_flags;
 623
 624 #ifdef CONFIG_IP_ROUTE_CLASSID
 625         nh->nh_tclassid = cfg->fc_flow;
 626         if (nh->nh_tclassid)
 627                 net->ipv4.fib_num_tclassid_users++;
 628 #endif
 629 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 630         nh->fib_nh_weight = nh_weight;
 631 #endif
 632         return 0;
 633 }
 634
 635 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 636
 637 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 638                               struct netlink_ext_ack *extack)
 639 {
 640         int nhs = 0;
 641
 642         while (rtnh_ok(rtnh, remaining)) {
 643                 nhs++;
 644                 rtnh = rtnh_next(rtnh, &remaining);
 645         }
 646
 647         /* leftover implies invalid nexthop configuration, discard it */
 648         if (remaining > 0) {
 649                 NL_SET_ERR_MSG(extack,
 650                                "Invalid nexthop configuration - extra data after nexthops");
 651                 nhs = 0;
 652         }
 653
 654         return nhs;
 655 }
 656
 657 /* only called when fib_nh is integrated into fib_info */
 658 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 659                        int remaining, struct fib_config *cfg,
 660                        struct netlink_ext_ack *extack)
 661 {
 662         struct net *net = fi->fib_net;
 663         struct fib_config fib_cfg;
 664         struct fib_nh *nh;
 665         int ret;
 666
 667         change_nexthops(fi) {
 668                 int attrlen;
 669
 670                 memset(&fib_cfg, 0, sizeof(fib_cfg));
 671
 672                 if (!rtnh_ok(rtnh, remaining)) {
 673                         NL_SET_ERR_MSG(extack,
 674                                        "Invalid nexthop configuration - extra data after nexthop");
 675                         return -EINVAL;
 676                 }
 677
 678                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 679                         NL_SET_ERR_MSG(extack,
 680                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 681                         return -EINVAL;
 682                 }
 683
 684                 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 685                 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 686
 687                 attrlen = rtnh_attrlen(rtnh);
 688                 if (attrlen > 0) {
 689                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 690
 691                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 692                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 693                         if (nla && nlav) {
 694                                 NL_SET_ERR_MSG(extack,
 695                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 696                                 return -EINVAL;
 697                         }
 698                         if (nla) {
 699                                 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
 700                                 if (fib_cfg.fc_gw4)
 701                                         fib_cfg.fc_gw_family = AF_INET;
 702                         } else if (nlav) {
 703                                 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 704                                 if (ret)
 705                                         goto errout;
 706                         }
 707
 708                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 709                         if (nla)
 710                                 fib_cfg.fc_flow = nla_get_u32(nla);
 711
 712                         fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 713                         nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 714                         if (nla)
 715                                 fib_cfg.fc_encap_type = nla_get_u16(nla);
 716                 }
 717
 718                 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 719                                   rtnh->rtnh_hops + 1, extack);
 720                 if (ret)
 721                         goto errout;
 722
 723                 rtnh = rtnh_next(rtnh, &remaining);
 724         } endfor_nexthops(fi);
 725
 726         ret = -EINVAL;
 727         nh = fib_info_nh(fi, 0);
 728         if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 729                 NL_SET_ERR_MSG(extack,
 730                                "Nexthop device index does not match RTA_OIF");
 731                 goto errout;
 732         }
 733         if (cfg->fc_gw_family) {
 734                 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 735                     (cfg->fc_gw_family == AF_INET &&
 736                      nh->fib_nh_gw4 != cfg->fc_gw4) ||
 737                     (cfg->fc_gw_family == AF_INET6 &&
 738                      ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 739                         NL_SET_ERR_MSG(extack,
 740                                        "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 741                         goto errout;
 742                 }
 743         }
 744 #ifdef CONFIG_IP_ROUTE_CLASSID
 745         if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 746                 NL_SET_ERR_MSG(extack,
 747                                "Nexthop class id does not match RTA_FLOW");
 748                 goto errout;
 749         }
 750 #endif
 751         ret = 0;
 752 errout:
 753         return ret;
 754 }
 755
 756 /* only called when fib_nh is integrated into fib_info */
 757 static void fib_rebalance(struct fib_info *fi)
 758 {
 759         int total;
 760         int w;
 761
 762         if (fib_info_num_path(fi) < 2)
 763                 return;
 764
 765         total = 0;
 766         for_nexthops(fi) {
 767                 if (nh->fib_nh_flags & RTNH_F_DEAD)
 768                         continue;
 769
 770                 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 771                     nh->fib_nh_flags & RTNH_F_LINKDOWN)
 772                         continue;
 773
 774                 total += nh->fib_nh_weight;
 775         } endfor_nexthops(fi);
 776
 777         w = 0;
 778         change_nexthops(fi) {
 779                 int upper_bound;
 780
 781                 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 782                         upper_bound = -1;
 783                 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 784                            nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 785                         upper_bound = -1;
 786                 } else {
 787                         w += nexthop_nh->fib_nh_weight;
 788                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 789                                                             total) - 1;
 790                 }
 791
 792                 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 793         } endfor_nexthops(fi);
 794 }
 795 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 796
 797 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 798                        int remaining, struct fib_config *cfg,
 799                        struct netlink_ext_ack *extack)
 800 {
 801         NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 802
 803         return -EINVAL;
 804 }
 805
 806 #define fib_rebalance(fi) do { } while (0)
 807
 808 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 809
 810 static int fib_encap_match(u16 encap_type,
 811                            struct nlattr *encap,
 812                            const struct fib_nh *nh,
 813                            const struct fib_config *cfg,
 814                            struct netlink_ext_ack *extack)
 815 {
 816         struct lwtunnel_state *lwtstate;
 817         int ret, result = 0;
 818
 819         if (encap_type == LWTUNNEL_ENCAP_NONE)
 820                 return 0;
 821
 822         ret = lwtunnel_build_state(encap_type, encap, AF_INET,
 823                                    cfg, &lwtstate, extack);
 824         if (!ret) {
 825                 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 826                 lwtstate_free(lwtstate);
 827         }
 828
 829         return result;
 830 }
 831
 832 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
 833                  struct netlink_ext_ack *extack)
 834 {
 835 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 836         struct rtnexthop *rtnh;
 837         int remaining;
 838 #endif
 839
 840         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 841                 return 1;
 842
 843         if (cfg->fc_nh_id) {
 844                 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 845                         return 0;
 846                 return 1;
 847         }
 848
 849         if (cfg->fc_oif || cfg->fc_gw_family) {
 850                 struct fib_nh *nh = fib_info_nh(fi, 0);
 851
 852                 if (cfg->fc_encap) {
 853                         if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
 854                                             nh, cfg, extack))
 855                                 return 1;
 856                 }
 857 #ifdef CONFIG_IP_ROUTE_CLASSID
 858                 if (cfg->fc_flow &&
 859                     cfg->fc_flow != nh->nh_tclassid)
 860                         return 1;
 861 #endif
 862                 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 863                     (cfg->fc_gw_family &&
 864                      cfg->fc_gw_family != nh->fib_nh_gw_family))
 865                         return 1;
 866
 867                 if (cfg->fc_gw_family == AF_INET &&
 868                     cfg->fc_gw4 != nh->fib_nh_gw4)
 869                         return 1;
 870
 871                 if (cfg->fc_gw_family == AF_INET6 &&
 872                     ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 873                         return 1;
 874
 875                 return 0;
 876         }
 877
 878 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 879         if (!cfg->fc_mp)
 880                 return 0;
 881
 882         rtnh = cfg->fc_mp;
 883         remaining = cfg->fc_mp_len;
 884
 885         for_nexthops(fi) {
 886                 int attrlen;
 887
 888                 if (!rtnh_ok(rtnh, remaining))
 889                         return -EINVAL;
 890
 891                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 892                         return 1;
 893
 894                 attrlen = rtnh_attrlen(rtnh);
 895                 if (attrlen > 0) {
 896                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 897
 898                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 899                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 900                         if (nla && nlav) {
 901                                 NL_SET_ERR_MSG(extack,
 902                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 903                                 return -EINVAL;
 904                         }
 905
 906                         if (nla) {
 907                                 if (nh->fib_nh_gw_family != AF_INET ||
 908                                     nla_get_in_addr(nla) != nh->fib_nh_gw4)
 909                                         return 1;
 910                         } else if (nlav) {
 911                                 struct fib_config cfg2;
 912                                 int err;
 913
 914                                 err = fib_gw_from_via(&cfg2, nlav, extack);
 915                                 if (err)
 916                                         return err;
 917
 918                                 switch (nh->fib_nh_gw_family) {
 919                                 case AF_INET:
 920                                         if (cfg2.fc_gw_family != AF_INET ||
 921                                             cfg2.fc_gw4 != nh->fib_nh_gw4)
 922                                                 return 1;
 923                                         break;
 924                                 case AF_INET6:
 925                                         if (cfg2.fc_gw_family != AF_INET6 ||
 926                                             ipv6_addr_cmp(&cfg2.fc_gw6,
 927                                                           &nh->fib_nh_gw6))
 928                                                 return 1;
 929                                         break;
 930                                 }
 931                         }
 932
 933 #ifdef CONFIG_IP_ROUTE_CLASSID
 934                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 935                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 936                                 return 1;
 937 #endif
 938                 }
 939
 940                 rtnh = rtnh_next(rtnh, &remaining);
 941         } endfor_nexthops(fi);
 942 #endif
 943         return 0;
 944 }
 945
 946 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 947 {
 948         struct nlattr *nla;
 949         int remaining;
 950
 951         if (!cfg->fc_mx)
 952                 return true;
 953
 954         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 955                 int type = nla_type(nla);
 956                 u32 fi_val, val;
 957
 958                 if (!type)
 959                         continue;
 960                 if (type > RTAX_MAX)
 961                         return false;
 962
 963                 if (type == RTAX_CC_ALGO) {
 964                         char tmp[TCP_CA_NAME_MAX];
 965                         bool ecn_ca = false;
 966
 967                         nla_strlcpy(tmp, nla, sizeof(tmp));
 968                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 969                 } else {
 970                         if (nla_len(nla) != sizeof(u32))
 971                                 return false;
 972                         val = nla_get_u32(nla);
 973                 }
 974
 975                 fi_val = fi->fib_metrics->metrics[type - 1];
 976                 if (type == RTAX_FEATURES)
 977                         fi_val &= ~DST_FEATURE_ECN_CA;
 978
 979                 if (fi_val != val)
 980                         return false;
 981         }
 982
 983         return true;
 984 }
 985
 986 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
 987                               u32 table, struct netlink_ext_ack *extack)
 988 {
 989         struct fib6_config cfg = {
 990                 .fc_table = table,
 991                 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
 992                 .fc_ifindex = nh->fib_nh_oif,
 993                 .fc_gateway = nh->fib_nh_gw6,
 994         };
 995         struct fib6_nh fib6_nh = {};
 996         int err;
 997
 998         err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
 999         if (!err) {
1000                 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1001                 dev_hold(nh->fib_nh_dev);
1002                 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1003                 nh->fib_nh_scope = RT_SCOPE_LINK;
1004
1005                 ipv6_stub->fib6_nh_release(&fib6_nh);
1006         }
1007
1008         return err;
1009 }
1010
1011 /*
1012  * Picture
1013  * -------
1014  *
1015  * Semantics of nexthop is very messy by historical reasons.
1016  * We have to take into account, that:
1017  * a) gateway can be actually local interface address,
1018  *    so that gatewayed route is direct.
1019  * b) gateway must be on-link address, possibly
1020  *    described not by an ifaddr, but also by a direct route.
1021  * c) If both gateway and interface are specified, they should not
1022  *    contradict.
1023  * d) If we use tunnel routes, gateway could be not on-link.
1024  *
1025  * Attempt to reconcile all of these (alas, self-contradictory) conditions
1026  * results in pretty ugly and hairy code with obscure logic.
1027  *
1028  * I chose to generalized it instead, so that the size
1029  * of code does not increase practically, but it becomes
1030  * much more general.
1031  * Every prefix is assigned a "scope" value: "host" is local address,
1032  * "link" is direct route,
1033  * [ ... "site" ... "interior" ... ]
1034  * and "universe" is true gateway route with global meaning.
1035  *
1036  * Every prefix refers to a set of "nexthop"s (gw, oif),
1037  * where gw must have narrower scope. This recursion stops
1038  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1039  * which means that gw is forced to be on link.
1040  *
1041  * Code is still hairy, but now it is apparently logically
1042  * consistent and very flexible. F.e. as by-product it allows
1043  * to co-exists in peace independent exterior and interior
1044  * routing processes.
1045  *
1046  * Normally it looks as following.
1047  *
1048  * {universe prefix}  -> (gw, oif) [scope link]
1049  *                |
1050  *                |-> {link prefix} -> (gw, oif) [scope local]
1051  *                                      |
1052  *                                      |-> {local prefix} (terminal node)
1053  */
1054 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1055                               u8 scope, struct netlink_ext_ack *extack)
1056 {
1057         struct net_device *dev;
1058         struct fib_result res;
1059         int err = 0;
1060
1061         if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1062                 unsigned int addr_type;
1063
1064                 if (scope >= RT_SCOPE_LINK) {
1065                         NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1066                         return -EINVAL;
1067                 }
1068                 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1069                 if (!dev) {
1070                         NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1071                         return -ENODEV;
1072                 }
1073                 if (!(dev->flags & IFF_UP)) {
1074                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1075                         return -ENETDOWN;
1076                 }
1077                 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1078                 if (addr_type != RTN_UNICAST) {
1079                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1080                         return -EINVAL;
1081                 }
1082                 if (!netif_carrier_ok(dev))
1083                         nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1084                 nh->fib_nh_dev = dev;
1085                 dev_hold(dev);
1086                 nh->fib_nh_scope = RT_SCOPE_LINK;
1087                 return 0;
1088         }
1089         rcu_read_lock();
1090         {
1091                 struct fib_table *tbl = NULL;
1092                 struct flowi4 fl4 = {
1093                         .daddr = nh->fib_nh_gw4,
1094                         .flowi4_scope = scope + 1,
1095                         .flowi4_oif = nh->fib_nh_oif,
1096                         .flowi4_iif = LOOPBACK_IFINDEX,
1097                 };
1098
1099                 /* It is not necessary, but requires a bit of thinking */
1100                 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1101                         fl4.flowi4_scope = RT_SCOPE_LINK;
1102
1103                 if (table)
1104                         tbl = fib_get_table(net, table);
1105
1106                 if (tbl)
1107                         err = fib_table_lookup(tbl, &fl4, &res,
1108                                                FIB_LOOKUP_IGNORE_LINKSTATE |
1109                                                FIB_LOOKUP_NOREF);
1110
1111                 /* on error or if no table given do full lookup. This
1112                  * is needed for example when nexthops are in the local
1113                  * table rather than the given table
1114                  */
1115                 if (!tbl || err) {
1116                         err = fib_lookup(net, &fl4, &res,
1117                                          FIB_LOOKUP_IGNORE_LINKSTATE);
1118                 }
1119
1120                 if (err) {
1121                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1122                         goto out;
1123                 }
1124         }
1125
1126         err = -EINVAL;
1127         if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1128                 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1129                 goto out;
1130         }
1131         nh->fib_nh_scope = res.scope;
1132         nh->fib_nh_oif = FIB_RES_OIF(res);
1133         nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1134         if (!dev) {
1135                 NL_SET_ERR_MSG(extack,
1136                                "No egress device for nexthop gateway");
1137                 goto out;
1138         }
1139         dev_hold(dev);
1140         if (!netif_carrier_ok(dev))
1141                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1142         err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1143 out:
1144         rcu_read_unlock();
1145         return err;
1146 }
1147
1148 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1149                               struct netlink_ext_ack *extack)
1150 {
1151         struct in_device *in_dev;
1152         int err;
1153
1154         if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1155                 NL_SET_ERR_MSG(extack,
1156                                "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1157                 return -EINVAL;
1158         }
1159
1160         rcu_read_lock();
1161
1162         err = -ENODEV;
1163         in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1164         if (!in_dev)
1165                 goto out;
1166         err = -ENETDOWN;
1167         if (!(in_dev->dev->flags & IFF_UP)) {
1168                 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1169                 goto out;
1170         }
1171
1172         nh->fib_nh_dev = in_dev->dev;
1173         dev_hold(nh->fib_nh_dev);
1174         nh->fib_nh_scope = RT_SCOPE_HOST;
1175         if (!netif_carrier_ok(nh->fib_nh_dev))
1176                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1177         err = 0;
1178 out:
1179         rcu_read_unlock();
1180         return err;
1181 }
1182
1183 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1184                  struct netlink_ext_ack *extack)
1185 {
1186         int err;
1187
1188         if (nh->fib_nh_gw_family == AF_INET)
1189                 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1190         else if (nh->fib_nh_gw_family == AF_INET6)
1191                 err = fib_check_nh_v6_gw(net, nh, table, extack);
1192         else
1193                 err = fib_check_nh_nongw(net, nh, extack);
1194
1195         return err;
1196 }
1197
1198 static inline unsigned int fib_laddr_hashfn(__be32 val)
1199 {
1200         unsigned int mask = (fib_info_hash_size - 1);
1201
1202         return ((__force u32)val ^
1203                 ((__force u32)val >> 7) ^
1204                 ((__force u32)val >> 14)) & mask;
1205 }
1206
1207 static struct hlist_head *fib_info_hash_alloc(int bytes)
1208 {
1209         if (bytes <= PAGE_SIZE)
1210                 return kzalloc(bytes, GFP_KERNEL);
1211         else
1212                 return (struct hlist_head *)
1213                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1214                                          get_order(bytes));
1215 }
1216
1217 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1218 {
1219         if (!hash)
1220                 return;
1221
1222         if (bytes <= PAGE_SIZE)
1223                 kfree(hash);
1224         else
1225                 free_pages((unsigned long) hash, get_order(bytes));
1226 }
1227
1228 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1229                                struct hlist_head *new_laddrhash,
1230                                unsigned int new_size)
1231 {
1232         struct hlist_head *old_info_hash, *old_laddrhash;
1233         unsigned int old_size = fib_info_hash_size;
1234         unsigned int i, bytes;
1235
1236         spin_lock_bh(&fib_info_lock);
1237         old_info_hash = fib_info_hash;
1238         old_laddrhash = fib_info_laddrhash;
1239         fib_info_hash_size = new_size;
1240
1241         for (i = 0; i < old_size; i++) {
1242                 struct hlist_head *head = &fib_info_hash[i];
1243                 struct hlist_node *n;
1244                 struct fib_info *fi;
1245
1246                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1247                         struct hlist_head *dest;
1248                         unsigned int new_hash;
1249
1250                         new_hash = fib_info_hashfn(fi);
1251                         dest = &new_info_hash[new_hash];
1252                         hlist_add_head(&fi->fib_hash, dest);
1253                 }
1254         }
1255         fib_info_hash = new_info_hash;
1256
1257         for (i = 0; i < old_size; i++) {
1258                 struct hlist_head *lhead = &fib_info_laddrhash[i];
1259                 struct hlist_node *n;
1260                 struct fib_info *fi;
1261
1262                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1263                         struct hlist_head *ldest;
1264                         unsigned int new_hash;
1265
1266                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1267                         ldest = &new_laddrhash[new_hash];
1268                         hlist_add_head(&fi->fib_lhash, ldest);
1269                 }
1270         }
1271         fib_info_laddrhash = new_laddrhash;
1272
1273         spin_unlock_bh(&fib_info_lock);
1274
1275         bytes = old_size * sizeof(struct hlist_head *);
1276         fib_info_hash_free(old_info_hash, bytes);
1277         fib_info_hash_free(old_laddrhash, bytes);
1278 }
1279
1280 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1281                                  unsigned char scope)
1282 {
1283         struct fib_nh *nh;
1284
1285         if (nhc->nhc_family != AF_INET)
1286                 return inet_select_addr(nhc->nhc_dev, 0, scope);
1287
1288         nh = container_of(nhc, struct fib_nh, nh_common);
1289         nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1290         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1291
1292         return nh->nh_saddr;
1293 }
1294
1295 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1296 {
1297         struct fib_nh_common *nhc = res->nhc;
1298
1299         if (res->fi->fib_prefsrc)
1300                 return res->fi->fib_prefsrc;
1301
1302         if (nhc->nhc_family == AF_INET) {
1303                 struct fib_nh *nh;
1304
1305                 nh = container_of(nhc, struct fib_nh, nh_common);
1306                 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1307                         return nh->nh_saddr;
1308         }
1309
1310         return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1311 }
1312
1313 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1314 {
1315         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1316             fib_prefsrc != cfg->fc_dst) {
1317                 u32 tb_id = cfg->fc_table;
1318                 int rc;
1319
1320                 if (tb_id == RT_TABLE_MAIN)
1321                         tb_id = RT_TABLE_LOCAL;
1322
1323                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1324                                           fib_prefsrc, tb_id);
1325
1326                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1327                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1328                                                   fib_prefsrc, RT_TABLE_LOCAL);
1329                 }
1330
1331                 if (rc != RTN_LOCAL)
1332                         return false;
1333         }
1334         return true;
1335 }
1336
1337 struct fib_info *fib_create_info(struct fib_config *cfg,
1338                                  struct netlink_ext_ack *extack)
1339 {
1340         int err;
1341         struct fib_info *fi = NULL;
1342         struct nexthop *nh = NULL;
1343         struct fib_info *ofi;
1344         int nhs = 1;
1345         struct net *net = cfg->fc_nlinfo.nl_net;
1346
1347         if (cfg->fc_type > RTN_MAX)
1348                 goto err_inval;
1349
1350         /* Fast check to catch the most weird cases */
1351         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1352                 NL_SET_ERR_MSG(extack, "Invalid scope");
1353                 goto err_inval;
1354         }
1355
1356         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1357                 NL_SET_ERR_MSG(extack,
1358                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1359                 goto err_inval;
1360         }
1361
1362         if (cfg->fc_nh_id) {
1363                 if (!cfg->fc_mx) {
1364                         fi = fib_find_info_nh(net, cfg);
1365                         if (fi) {
1366                                 fi->fib_treeref++;
1367                                 return fi;
1368                         }
1369                 }
1370
1371                 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1372                 if (!nh) {
1373                         NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1374                         goto err_inval;
1375                 }
1376                 nhs = 0;
1377         }
1378
1379 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1380         if (cfg->fc_mp) {
1381                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1382                 if (nhs == 0)
1383                         goto err_inval;
1384         }
1385 #endif
1386
1387         err = -ENOBUFS;
1388         if (fib_info_cnt >= fib_info_hash_size) {
1389                 unsigned int new_size = fib_info_hash_size << 1;
1390                 struct hlist_head *new_info_hash;
1391                 struct hlist_head *new_laddrhash;
1392                 unsigned int bytes;
1393
1394                 if (!new_size)
1395                         new_size = 16;
1396                 bytes = new_size * sizeof(struct hlist_head *);
1397                 new_info_hash = fib_info_hash_alloc(bytes);
1398                 new_laddrhash = fib_info_hash_alloc(bytes);
1399                 if (!new_info_hash || !new_laddrhash) {
1400                         fib_info_hash_free(new_info_hash, bytes);
1401                         fib_info_hash_free(new_laddrhash, bytes);
1402                 } else
1403                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1404
1405                 if (!fib_info_hash_size)
1406                         goto failure;
1407         }
1408
1409         fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1410         if (!fi)
1411                 goto failure;
1412         fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1413                                               cfg->fc_mx_len, extack);
1414         if (IS_ERR(fi->fib_metrics)) {
1415                 err = PTR_ERR(fi->fib_metrics);
1416                 kfree(fi);
1417                 return ERR_PTR(err);
1418         }
1419
1420         fib_info_cnt++;
1421         fi->fib_net = net;
1422         fi->fib_protocol = cfg->fc_protocol;
1423         fi->fib_scope = cfg->fc_scope;
1424         fi->fib_flags = cfg->fc_flags;
1425         fi->fib_priority = cfg->fc_priority;
1426         fi->fib_prefsrc = cfg->fc_prefsrc;
1427         fi->fib_type = cfg->fc_type;
1428         fi->fib_tb_id = cfg->fc_table;
1429
1430         fi->fib_nhs = nhs;
1431         if (nh) {
1432                 if (!nexthop_get(nh)) {
1433                         NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1434                         err = -EINVAL;
1435                 } else {
1436                         err = 0;
1437                         fi->nh = nh;
1438                 }
1439         } else {
1440                 change_nexthops(fi) {
1441                         nexthop_nh->nh_parent = fi;
1442                 } endfor_nexthops(fi)
1443
1444                 if (cfg->fc_mp)
1445                         err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1446                                           extack);
1447                 else
1448                         err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1449         }
1450
1451         if (err != 0)
1452                 goto failure;
1453
1454         if (fib_props[cfg->fc_type].error) {
1455                 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1456                         NL_SET_ERR_MSG(extack,
1457                                        "Gateway, device and multipath can not be specified for this route type");
1458                         goto err_inval;
1459                 }
1460                 goto link_it;
1461         } else {
1462                 switch (cfg->fc_type) {
1463                 case RTN_UNICAST:
1464                 case RTN_LOCAL:
1465                 case RTN_BROADCAST:
1466                 case RTN_ANYCAST:
1467                 case RTN_MULTICAST:
1468                         break;
1469                 default:
1470                         NL_SET_ERR_MSG(extack, "Invalid route type");
1471                         goto err_inval;
1472                 }
1473         }
1474
1475         if (cfg->fc_scope > RT_SCOPE_HOST) {
1476                 NL_SET_ERR_MSG(extack, "Invalid scope");
1477                 goto err_inval;
1478         }
1479
1480         if (fi->nh) {
1481                 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1482                 if (err)
1483                         goto failure;
1484         } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1485                 struct fib_nh *nh = fi->fib_nh;
1486
1487                 /* Local address is added. */
1488                 if (nhs != 1) {
1489                         NL_SET_ERR_MSG(extack,
1490                                        "Route with host scope can not have multiple nexthops");
1491                         goto err_inval;
1492                 }
1493                 if (nh->fib_nh_gw_family) {
1494                         NL_SET_ERR_MSG(extack,
1495                                        "Route with host scope can not have a gateway");
1496                         goto err_inval;
1497                 }
1498                 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1499                 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1500                 err = -ENODEV;
1501                 if (!nh->fib_nh_dev)
1502                         goto failure;
1503         } else {
1504                 int linkdown = 0;
1505
1506                 change_nexthops(fi) {
1507                         err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1508                                            cfg->fc_table, cfg->fc_scope,
1509                                            extack);
1510                         if (err != 0)
1511                                 goto failure;
1512                         if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1513                                 linkdown++;
1514                 } endfor_nexthops(fi)
1515                 if (linkdown == fi->fib_nhs)
1516                         fi->fib_flags |= RTNH_F_LINKDOWN;
1517         }
1518
1519         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1520                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1521                 goto err_inval;
1522         }
1523
1524         if (!fi->nh) {
1525                 change_nexthops(fi) {
1526                         fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1527                                                   fi->fib_scope);
1528                         if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1529                                 fi->fib_nh_is_v6 = true;
1530                 } endfor_nexthops(fi)
1531
1532                 fib_rebalance(fi);
1533         }
1534
1535 link_it:
1536         ofi = fib_find_info(fi);
1537         if (ofi) {
1538                 fi->fib_dead = 1;
1539                 free_fib_info(fi);
1540                 ofi->fib_treeref++;
1541                 return ofi;
1542         }
1543
1544         fi->fib_treeref++;
1545         refcount_set(&fi->fib_clntref, 1);
1546         spin_lock_bh(&fib_info_lock);
1547         hlist_add_head(&fi->fib_hash,
1548                        &fib_info_hash[fib_info_hashfn(fi)]);
1549         if (fi->fib_prefsrc) {
1550                 struct hlist_head *head;
1551
1552                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1553                 hlist_add_head(&fi->fib_lhash, head);
1554         }
1555         if (fi->nh) {
1556                 list_add(&fi->nh_list, &nh->fi_list);
1557         } else {
1558                 change_nexthops(fi) {
1559                         struct hlist_head *head;
1560                         unsigned int hash;
1561
1562                         if (!nexthop_nh->fib_nh_dev)
1563                                 continue;
1564                         hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1565                         head = &fib_info_devhash[hash];
1566                         hlist_add_head(&nexthop_nh->nh_hash, head);
1567                 } endfor_nexthops(fi)
1568         }
1569         spin_unlock_bh(&fib_info_lock);
1570         return fi;
1571
1572 err_inval:
1573         err = -EINVAL;
1574
1575 failure:
1576         if (fi) {
1577                 fi->fib_dead = 1;
1578                 free_fib_info(fi);
1579         }
1580
1581         return ERR_PTR(err);
1582 }
1583
1584 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1585                      u8 rt_family, unsigned char *flags, bool skip_oif)
1586 {
1587         if (nhc->nhc_flags & RTNH_F_DEAD)
1588                 *flags |= RTNH_F_DEAD;
1589
1590         if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1591                 *flags |= RTNH_F_LINKDOWN;
1592
1593                 rcu_read_lock();
1594                 switch (nhc->nhc_family) {
1595                 case AF_INET:
1596                         if (ip_ignore_linkdown(nhc->nhc_dev))
1597                                 *flags |= RTNH_F_DEAD;
1598                         break;
1599                 case AF_INET6:
1600                         if (ip6_ignore_linkdown(nhc->nhc_dev))
1601                                 *flags |= RTNH_F_DEAD;
1602                         break;
1603                 }
1604                 rcu_read_unlock();
1605         }
1606
1607         switch (nhc->nhc_gw_family) {
1608         case AF_INET:
1609                 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1610                         goto nla_put_failure;
1611                 break;
1612         case AF_INET6:
1613                 /* if gateway family does not match nexthop family
1614                  * gateway is encoded as RTA_VIA
1615                  */
1616                 if (rt_family != nhc->nhc_gw_family) {
1617                         int alen = sizeof(struct in6_addr);
1618                         struct nlattr *nla;
1619                         struct rtvia *via;
1620
1621                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
1622                         if (!nla)
1623                                 goto nla_put_failure;
1624
1625                         via = nla_data(nla);
1626                         via->rtvia_family = AF_INET6;
1627                         memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1628                 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1629                                             &nhc->nhc_gw.ipv6) < 0) {
1630                         goto nla_put_failure;
1631                 }
1632                 break;
1633         }
1634
1635         *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1636         if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1637                 *flags |= RTNH_F_OFFLOAD;
1638
1639         if (!skip_oif && nhc->nhc_dev &&
1640             nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1641                 goto nla_put_failure;
1642
1643         if (nhc->nhc_lwtstate &&
1644             lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1645                                 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1646                 goto nla_put_failure;
1647
1648         return 0;
1649
1650 nla_put_failure:
1651         return -EMSGSIZE;
1652 }
1653 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1654
1655 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1656 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1657                     int nh_weight, u8 rt_family)
1658 {
1659         const struct net_device *dev = nhc->nhc_dev;
1660         struct rtnexthop *rtnh;
1661         unsigned char flags = 0;
1662
1663         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1664         if (!rtnh)
1665                 goto nla_put_failure;
1666
1667         rtnh->rtnh_hops = nh_weight - 1;
1668         rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1669
1670         if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1671                 goto nla_put_failure;
1672
1673         rtnh->rtnh_flags = flags;
1674
1675         /* length of rtnetlink header + attributes */
1676         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1677
1678         return 0;
1679
1680 nla_put_failure:
1681         return -EMSGSIZE;
1682 }
1683 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1684 #endif
1685
1686 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1687 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1688 {
1689         struct nlattr *mp;
1690
1691         mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1692         if (!mp)
1693                 goto nla_put_failure;
1694
1695         if (unlikely(fi->nh)) {
1696                 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1697                         goto nla_put_failure;
1698                 goto mp_end;
1699         }
1700
1701         for_nexthops(fi) {
1702                 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1703                                     AF_INET) < 0)
1704                         goto nla_put_failure;
1705 #ifdef CONFIG_IP_ROUTE_CLASSID
1706                 if (nh->nh_tclassid &&
1707                     nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1708                         goto nla_put_failure;
1709 #endif
1710         } endfor_nexthops(fi);
1711
1712 mp_end:
1713         nla_nest_end(skb, mp);
1714
1715         return 0;
1716
1717 nla_put_failure:
1718         return -EMSGSIZE;
1719 }
1720 #else
1721 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1722 {
1723         return 0;
1724 }
1725 #endif
1726
1727 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1728                   u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1729                   struct fib_info *fi, unsigned int flags)
1730 {
1731         unsigned int nhs = fib_info_num_path(fi);
1732         struct nlmsghdr *nlh;
1733         struct rtmsg *rtm;
1734
1735         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1736         if (!nlh)
1737                 return -EMSGSIZE;
1738
1739         rtm = nlmsg_data(nlh);
1740         rtm->rtm_family = AF_INET;
1741         rtm->rtm_dst_len = dst_len;
1742         rtm->rtm_src_len = 0;
1743         rtm->rtm_tos = tos;
1744         if (tb_id < 256)
1745                 rtm->rtm_table = tb_id;
1746         else
1747                 rtm->rtm_table = RT_TABLE_COMPAT;
1748         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1749                 goto nla_put_failure;
1750         rtm->rtm_type = type;
1751         rtm->rtm_flags = fi->fib_flags;
1752         rtm->rtm_scope = fi->fib_scope;
1753         rtm->rtm_protocol = fi->fib_protocol;
1754
1755         if (rtm->rtm_dst_len &&
1756             nla_put_in_addr(skb, RTA_DST, dst))
1757                 goto nla_put_failure;
1758         if (fi->fib_priority &&
1759             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1760                 goto nla_put_failure;
1761         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1762                 goto nla_put_failure;
1763
1764         if (fi->fib_prefsrc &&
1765             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1766                 goto nla_put_failure;
1767
1768         if (fi->nh) {
1769                 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1770                         goto nla_put_failure;
1771                 if (nexthop_is_blackhole(fi->nh))
1772                         rtm->rtm_type = RTN_BLACKHOLE;
1773         }
1774
1775         if (nhs == 1) {
1776                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1777                 unsigned char flags = 0;
1778
1779                 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1780                         goto nla_put_failure;
1781
1782                 rtm->rtm_flags = flags;
1783 #ifdef CONFIG_IP_ROUTE_CLASSID
1784                 if (nhc->nhc_family == AF_INET) {
1785                         struct fib_nh *nh;
1786
1787                         nh = container_of(nhc, struct fib_nh, nh_common);
1788                         if (nh->nh_tclassid &&
1789                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1790                                 goto nla_put_failure;
1791                 }
1792 #endif
1793         } else {
1794                 if (fib_add_multipath(skb, fi) < 0)
1795                         goto nla_put_failure;
1796         }
1797
1798         nlmsg_end(skb, nlh);
1799         return 0;
1800
1801 nla_put_failure:
1802         nlmsg_cancel(skb, nlh);
1803         return -EMSGSIZE;
1804 }
1805
1806 /*
1807  * Update FIB if:
1808  * - local address disappeared -> we must delete all the entries
1809  *   referring to it.
1810  * - device went down -> we must shutdown all nexthops going via it.
1811  */
1812 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1813 {
1814         int ret = 0;
1815         unsigned int hash = fib_laddr_hashfn(local);
1816         struct hlist_head *head = &fib_info_laddrhash[hash];
1817         int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1818         struct net *net = dev_net(dev);
1819         struct fib_info *fi;
1820
1821         if (!fib_info_laddrhash || local == 0)
1822                 return 0;
1823
1824         hlist_for_each_entry(fi, head, fib_lhash) {
1825                 if (!net_eq(fi->fib_net, net) ||
1826                     fi->fib_tb_id != tb_id)
1827                         continue;
1828                 if (fi->fib_prefsrc == local) {
1829                         fi->fib_flags |= RTNH_F_DEAD;
1830                         ret++;
1831                 }
1832         }
1833         return ret;
1834 }
1835
1836 static int call_fib_nh_notifiers(struct fib_nh *nh,
1837                                  enum fib_event_type event_type)
1838 {
1839         bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1840         struct fib_nh_notifier_info info = {
1841                 .fib_nh = nh,
1842         };
1843
1844         switch (event_type) {
1845         case FIB_EVENT_NH_ADD:
1846                 if (nh->fib_nh_flags & RTNH_F_DEAD)
1847                         break;
1848                 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1849                         break;
1850                 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1851                                            &info.info);
1852         case FIB_EVENT_NH_DEL:
1853                 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1854                     (nh->fib_nh_flags & RTNH_F_DEAD))
1855                         return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1856                                                    event_type, &info.info);
1857         default:
1858                 break;
1859         }
1860
1861         return NOTIFY_DONE;
1862 }
1863
1864 /* Update the PMTU of exceptions when:
1865  * - the new MTU of the first hop becomes smaller than the PMTU
1866  * - the old MTU was the same as the PMTU, and it limited discovery of
1867  *   larger MTUs on the path. With that limit raised, we can now
1868  *   discover larger MTUs
1869  * A special case is locked exceptions, for which the PMTU is smaller
1870  * than the minimal accepted PMTU:
1871  * - if the new MTU is greater than the PMTU, don't make any change
1872  * - otherwise, unlock and set PMTU
1873  */
1874 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1875 {
1876         struct fnhe_hash_bucket *bucket;
1877         int i;
1878
1879         bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1880         if (!bucket)
1881                 return;
1882
1883         for (i = 0; i < FNHE_HASH_SIZE; i++) {
1884                 struct fib_nh_exception *fnhe;
1885
1886                 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1887                      fnhe;
1888                      fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1889                         if (fnhe->fnhe_mtu_locked) {
1890                                 if (new <= fnhe->fnhe_pmtu) {
1891                                         fnhe->fnhe_pmtu = new;
1892                                         fnhe->fnhe_mtu_locked = false;
1893                                 }
1894                         } else if (new < fnhe->fnhe_pmtu ||
1895                                    orig == fnhe->fnhe_pmtu) {
1896                                 fnhe->fnhe_pmtu = new;
1897                         }
1898                 }
1899         }
1900 }
1901
1902 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1903 {
1904         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1905         struct hlist_head *head = &fib_info_devhash[hash];
1906         struct fib_nh *nh;
1907
1908         hlist_for_each_entry(nh, head, nh_hash) {
1909                 if (nh->fib_nh_dev == dev)
1910                         fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1911         }
1912 }
1913
1914 /* Event              force Flags           Description
1915  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1916  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1917  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1918  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1919  *
1920  * only used when fib_nh is built into fib_info
1921  */
1922 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1923 {
1924         int ret = 0;
1925         int scope = RT_SCOPE_NOWHERE;
1926         struct fib_info *prev_fi = NULL;
1927         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1928         struct hlist_head *head = &fib_info_devhash[hash];
1929         struct fib_nh *nh;
1930
1931         if (force)
1932                 scope = -1;
1933
1934         hlist_for_each_entry(nh, head, nh_hash) {
1935                 struct fib_info *fi = nh->nh_parent;
1936                 int dead;
1937
1938                 BUG_ON(!fi->fib_nhs);
1939                 if (nh->fib_nh_dev != dev || fi == prev_fi)
1940                         continue;
1941                 prev_fi = fi;
1942                 dead = 0;
1943                 change_nexthops(fi) {
1944                         if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1945                                 dead++;
1946                         else if (nexthop_nh->fib_nh_dev == dev &&
1947                                  nexthop_nh->fib_nh_scope != scope) {
1948                                 switch (event) {
1949                                 case NETDEV_DOWN:
1950                                 case NETDEV_UNREGISTER:
1951                                         nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1952                                         /* fall through */
1953                                 case NETDEV_CHANGE:
1954                                         nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1955                                         break;
1956                                 }
1957                                 call_fib_nh_notifiers(nexthop_nh,
1958                                                       FIB_EVENT_NH_DEL);
1959                                 dead++;
1960                         }
1961 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1962                         if (event == NETDEV_UNREGISTER &&
1963                             nexthop_nh->fib_nh_dev == dev) {
1964                                 dead = fi->fib_nhs;
1965                                 break;
1966                         }
1967 #endif
1968                 } endfor_nexthops(fi)
1969                 if (dead == fi->fib_nhs) {
1970                         switch (event) {
1971                         case NETDEV_DOWN:
1972                         case NETDEV_UNREGISTER:
1973                                 fi->fib_flags |= RTNH_F_DEAD;
1974                                 /* fall through */
1975                         case NETDEV_CHANGE:
1976                                 fi->fib_flags |= RTNH_F_LINKDOWN;
1977                                 break;
1978                         }
1979                         ret++;
1980                 }
1981
1982                 fib_rebalance(fi);
1983         }
1984
1985         return ret;
1986 }
1987
1988 /* Must be invoked inside of an RCU protected region.  */
1989 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1990 {
1991         struct fib_info *fi = NULL, *last_resort = NULL;
1992         struct hlist_head *fa_head = res->fa_head;
1993         struct fib_table *tb = res->table;
1994         u8 slen = 32 - res->prefixlen;
1995         int order = -1, last_idx = -1;
1996         struct fib_alias *fa, *fa1 = NULL;
1997         u32 last_prio = res->fi->fib_priority;
1998         u8 last_tos = 0;
1999
2000         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2001                 struct fib_info *next_fi = fa->fa_info;
2002                 struct fib_nh *nh;
2003
2004                 if (fa->fa_slen != slen)
2005                         continue;
2006                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2007                         continue;
2008                 if (fa->tb_id != tb->tb_id)
2009                         continue;
2010                 if (next_fi->fib_priority > last_prio &&
2011                     fa->fa_tos == last_tos) {
2012                         if (last_tos)
2013                                 continue;
2014                         break;
2015                 }
2016                 if (next_fi->fib_flags & RTNH_F_DEAD)
2017                         continue;
2018                 last_tos = fa->fa_tos;
2019                 last_prio = next_fi->fib_priority;
2020
2021                 if (next_fi->fib_scope != res->scope ||
2022                     fa->fa_type != RTN_UNICAST)
2023                         continue;
2024
2025                 nh = fib_info_nh(next_fi, 0);
2026                 if (!nh->fib_nh_gw4 || nh->fib_nh_scope != RT_SCOPE_LINK)
2027                         continue;
2028
2029                 fib_alias_accessed(fa);
2030
2031                 if (!fi) {
2032                         if (next_fi != res->fi)
2033                                 break;
2034                         fa1 = fa;
2035                 } else if (!fib_detect_death(fi, order, &last_resort,
2036                                              &last_idx, fa1->fa_default)) {
2037                         fib_result_assign(res, fi);
2038                         fa1->fa_default = order;
2039                         goto out;
2040                 }
2041                 fi = next_fi;
2042                 order++;
2043         }
2044
2045         if (order <= 0 || !fi) {
2046                 if (fa1)
2047                         fa1->fa_default = -1;
2048                 goto out;
2049         }
2050
2051         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2052                               fa1->fa_default)) {
2053                 fib_result_assign(res, fi);
2054                 fa1->fa_default = order;
2055                 goto out;
2056         }
2057
2058         if (last_idx >= 0)
2059                 fib_result_assign(res, last_resort);
2060         fa1->fa_default = last_idx;
2061 out:
2062         return;
2063 }
2064
2065 /*
2066  * Dead device goes up. We wake up dead nexthops.
2067  * It takes sense only on multipath routes.
2068  *
2069  * only used when fib_nh is built into fib_info
2070  */
2071 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2072 {
2073         struct fib_info *prev_fi;
2074         unsigned int hash;
2075         struct hlist_head *head;
2076         struct fib_nh *nh;
2077         int ret;
2078
2079         if (!(dev->flags & IFF_UP))
2080                 return 0;
2081
2082         if (nh_flags & RTNH_F_DEAD) {
2083                 unsigned int flags = dev_get_flags(dev);
2084
2085                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2086                         nh_flags |= RTNH_F_LINKDOWN;
2087         }
2088
2089         prev_fi = NULL;
2090         hash = fib_devindex_hashfn(dev->ifindex);
2091         head = &fib_info_devhash[hash];
2092         ret = 0;
2093
2094         hlist_for_each_entry(nh, head, nh_hash) {
2095                 struct fib_info *fi = nh->nh_parent;
2096                 int alive;
2097
2098                 BUG_ON(!fi->fib_nhs);
2099                 if (nh->fib_nh_dev != dev || fi == prev_fi)
2100                         continue;
2101
2102                 prev_fi = fi;
2103                 alive = 0;
2104                 change_nexthops(fi) {
2105                         if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2106                                 alive++;
2107                                 continue;
2108                         }
2109                         if (!nexthop_nh->fib_nh_dev ||
2110                             !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2111                                 continue;
2112                         if (nexthop_nh->fib_nh_dev != dev ||
2113                             !__in_dev_get_rtnl(dev))
2114                                 continue;
2115                         alive++;
2116                         nexthop_nh->fib_nh_flags &= ~nh_flags;
2117                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2118                 } endfor_nexthops(fi)
2119
2120                 if (alive > 0) {
2121                         fi->fib_flags &= ~nh_flags;
2122                         ret++;
2123                 }
2124
2125                 fib_rebalance(fi);
2126         }
2127
2128         return ret;
2129 }
2130
2131 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2132 static bool fib_good_nh(const struct fib_nh *nh)
2133 {
2134         int state = NUD_REACHABLE;
2135
2136         if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2137                 struct neighbour *n;
2138
2139                 rcu_read_lock_bh();
2140
2141                 if (likely(nh->fib_nh_gw_family == AF_INET))
2142                         n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2143                                                    (__force u32)nh->fib_nh_gw4);
2144                 else if (nh->fib_nh_gw_family == AF_INET6)
2145                         n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2146                                                            &nh->fib_nh_gw6);
2147                 else
2148                         n = NULL;
2149                 if (n)
2150                         state = n->nud_state;
2151
2152                 rcu_read_unlock_bh();
2153         }
2154
2155         return !!(state & NUD_VALID);
2156 }
2157
2158 void fib_select_multipath(struct fib_result *res, int hash)
2159 {
2160         struct fib_info *fi = res->fi;
2161         struct net *net = fi->fib_net;
2162         bool first = false;
2163
2164         if (unlikely(res->fi->nh)) {
2165                 nexthop_path_fib_result(res, hash);
2166                 return;
2167         }
2168
2169         change_nexthops(fi) {
2170                 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2171                         if (!fib_good_nh(nexthop_nh))
2172                                 continue;
2173                         if (!first) {
2174                                 res->nh_sel = nhsel;
2175                                 res->nhc = &nexthop_nh->nh_common;
2176                                 first = true;
2177                         }
2178                 }
2179
2180                 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2181                         continue;
2182
2183                 res->nh_sel = nhsel;
2184                 res->nhc = &nexthop_nh->nh_common;
2185                 return;
2186         } endfor_nexthops(fi);
2187 }
2188 #endif
2189
2190 void fib_select_path(struct net *net, struct fib_result *res,
2191                      struct flowi4 *fl4, const struct sk_buff *skb)
2192 {
2193         if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2194                 goto check_saddr;
2195
2196 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2197         if (fib_info_num_path(res->fi) > 1) {
2198                 int h = fib_multipath_hash(net, fl4, skb, NULL);
2199
2200                 fib_select_multipath(res, h);
2201         }
2202         else
2203 #endif
2204         if (!res->prefixlen &&
2205             res->table->tb_num_default > 1 &&
2206             res->type == RTN_UNICAST)
2207                 fib_select_default(fl4, res);
2208
2209 check_saddr:
2210         if (!fl4->saddr)
2211                 fl4->saddr = fib_result_prefsrc(net, res);
2212 }