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 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 fib_rt_info fri;
 508         struct sk_buff *skb;
 509         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 510         int err = -ENOBUFS;
 511
 512         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 513         if (!skb)
 514                 goto errout;
 515
 516         fri.fi = fa->fa_info;
 517         fri.tb_id = tb_id;
 518         fri.dst = key;
 519         fri.dst_len = dst_len;
 520         fri.tos = fa->fa_tos;
 521         fri.type = fa->fa_type;
 522         fri.offload = fa->offload;
 523         fri.trap = fa->trap;
 524         fri.offload_failed = fa->offload_failed;
 525         err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
 526         if (err < 0) {
 527                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 528                 WARN_ON(err == -EMSGSIZE);
 529                 kfree_skb(skb);
 530                 goto errout;
 531         }
 532         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 533                     info->nlh, GFP_KERNEL);
 534         return;
 535 errout:
 536         if (err < 0)
 537                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 538 }
 539
 540 static int fib_detect_death(struct fib_info *fi, int order,
 541                             struct fib_info **last_resort, int *last_idx,
 542                             int dflt)
 543 {
 544         const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 545         struct neighbour *n;
 546         int state = NUD_NONE;
 547
 548         if (likely(nhc->nhc_gw_family == AF_INET))
 549                 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 550         else if (nhc->nhc_gw_family == AF_INET6)
 551                 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 552                                  nhc->nhc_dev);
 553         else
 554                 n = NULL;
 555
 556         if (n) {
 557                 state = n->nud_state;
 558                 neigh_release(n);
 559         } else {
 560                 return 0;
 561         }
 562         if (state == NUD_REACHABLE)
 563                 return 0;
 564         if ((state & NUD_VALID) && order != dflt)
 565                 return 0;
 566         if ((state & NUD_VALID) ||
 567             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 568                 *last_resort = fi;
 569                 *last_idx = order;
 570         }
 571         return 1;
 572 }
 573
 574 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 575                        struct nlattr *encap, u16 encap_type,
 576                        void *cfg, gfp_t gfp_flags,
 577                        struct netlink_ext_ack *extack)
 578 {
 579         int err;
 580
 581         nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 582                                                     gfp_flags);
 583         if (!nhc->nhc_pcpu_rth_output)
 584                 return -ENOMEM;
 585
 586         if (encap) {
 587                 struct lwtunnel_state *lwtstate;
 588
 589                 if (encap_type == LWTUNNEL_ENCAP_NONE) {
 590                         NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 591                         err = -EINVAL;
 592                         goto lwt_failure;
 593                 }
 594                 err = lwtunnel_build_state(net, encap_type, encap,
 595                                            nhc->nhc_family, cfg, &lwtstate,
 596                                            extack);
 597                 if (err)
 598                         goto lwt_failure;
 599
 600                 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 601         }
 602
 603         return 0;
 604
 605 lwt_failure:
 606         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 607         nhc->nhc_pcpu_rth_output = NULL;
 608         return err;
 609 }
 610 EXPORT_SYMBOL_GPL(fib_nh_common_init);
 611
 612 int fib_nh_init(struct net *net, struct fib_nh *nh,
 613                 struct fib_config *cfg, int nh_weight,
 614                 struct netlink_ext_ack *extack)
 615 {
 616         int err;
 617
 618         nh->fib_nh_family = AF_INET;
 619
 620         err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
 621                                  cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 622         if (err)
 623                 return err;
 624
 625         nh->fib_nh_oif = cfg->fc_oif;
 626         nh->fib_nh_gw_family = cfg->fc_gw_family;
 627         if (cfg->fc_gw_family == AF_INET)
 628                 nh->fib_nh_gw4 = cfg->fc_gw4;
 629         else if (cfg->fc_gw_family == AF_INET6)
 630                 nh->fib_nh_gw6 = cfg->fc_gw6;
 631
 632         nh->fib_nh_flags = cfg->fc_flags;
 633
 634 #ifdef CONFIG_IP_ROUTE_CLASSID
 635         nh->nh_tclassid = cfg->fc_flow;
 636         if (nh->nh_tclassid)
 637                 net->ipv4.fib_num_tclassid_users++;
 638 #endif
 639 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 640         nh->fib_nh_weight = nh_weight;
 641 #endif
 642         return 0;
 643 }
 644
 645 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 646
 647 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 648                               struct netlink_ext_ack *extack)
 649 {
 650         int nhs = 0;
 651
 652         while (rtnh_ok(rtnh, remaining)) {
 653                 nhs++;
 654                 rtnh = rtnh_next(rtnh, &remaining);
 655         }
 656
 657         /* leftover implies invalid nexthop configuration, discard it */
 658         if (remaining > 0) {
 659                 NL_SET_ERR_MSG(extack,
 660                                "Invalid nexthop configuration - extra data after nexthops");
 661                 nhs = 0;
 662         }
 663
 664         return nhs;
 665 }
 666
 667 /* only called when fib_nh is integrated into fib_info */
 668 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 669                        int remaining, struct fib_config *cfg,
 670                        struct netlink_ext_ack *extack)
 671 {
 672         struct net *net = fi->fib_net;
 673         struct fib_config fib_cfg;
 674         struct fib_nh *nh;
 675         int ret;
 676
 677         change_nexthops(fi) {
 678                 int attrlen;
 679
 680                 memset(&fib_cfg, 0, sizeof(fib_cfg));
 681
 682                 if (!rtnh_ok(rtnh, remaining)) {
 683                         NL_SET_ERR_MSG(extack,
 684                                        "Invalid nexthop configuration - extra data after nexthop");
 685                         return -EINVAL;
 686                 }
 687
 688                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 689                         NL_SET_ERR_MSG(extack,
 690                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 691                         return -EINVAL;
 692                 }
 693
 694                 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 695                 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 696
 697                 attrlen = rtnh_attrlen(rtnh);
 698                 if (attrlen > 0) {
 699                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 700
 701                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 702                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 703                         if (nla && nlav) {
 704                                 NL_SET_ERR_MSG(extack,
 705                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 706                                 return -EINVAL;
 707                         }
 708                         if (nla) {
 709                                 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
 710                                 if (fib_cfg.fc_gw4)
 711                                         fib_cfg.fc_gw_family = AF_INET;
 712                         } else if (nlav) {
 713                                 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 714                                 if (ret)
 715                                         goto errout;
 716                         }
 717
 718                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 719                         if (nla)
 720                                 fib_cfg.fc_flow = nla_get_u32(nla);
 721
 722                         fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 723                         nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 724                         if (nla)
 725                                 fib_cfg.fc_encap_type = nla_get_u16(nla);
 726                 }
 727
 728                 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 729                                   rtnh->rtnh_hops + 1, extack);
 730                 if (ret)
 731                         goto errout;
 732
 733                 rtnh = rtnh_next(rtnh, &remaining);
 734         } endfor_nexthops(fi);
 735
 736         ret = -EINVAL;
 737         nh = fib_info_nh(fi, 0);
 738         if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 739                 NL_SET_ERR_MSG(extack,
 740                                "Nexthop device index does not match RTA_OIF");
 741                 goto errout;
 742         }
 743         if (cfg->fc_gw_family) {
 744                 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 745                     (cfg->fc_gw_family == AF_INET &&
 746                      nh->fib_nh_gw4 != cfg->fc_gw4) ||
 747                     (cfg->fc_gw_family == AF_INET6 &&
 748                      ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 749                         NL_SET_ERR_MSG(extack,
 750                                        "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 751                         goto errout;
 752                 }
 753         }
 754 #ifdef CONFIG_IP_ROUTE_CLASSID
 755         if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 756                 NL_SET_ERR_MSG(extack,
 757                                "Nexthop class id does not match RTA_FLOW");
 758                 goto errout;
 759         }
 760 #endif
 761         ret = 0;
 762 errout:
 763         return ret;
 764 }
 765
 766 /* only called when fib_nh is integrated into fib_info */
 767 static void fib_rebalance(struct fib_info *fi)
 768 {
 769         int total;
 770         int w;
 771
 772         if (fib_info_num_path(fi) < 2)
 773                 return;
 774
 775         total = 0;
 776         for_nexthops(fi) {
 777                 if (nh->fib_nh_flags & RTNH_F_DEAD)
 778                         continue;
 779
 780                 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 781                     nh->fib_nh_flags & RTNH_F_LINKDOWN)
 782                         continue;
 783
 784                 total += nh->fib_nh_weight;
 785         } endfor_nexthops(fi);
 786
 787         w = 0;
 788         change_nexthops(fi) {
 789                 int upper_bound;
 790
 791                 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 792                         upper_bound = -1;
 793                 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 794                            nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 795                         upper_bound = -1;
 796                 } else {
 797                         w += nexthop_nh->fib_nh_weight;
 798                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 799                                                             total) - 1;
 800                 }
 801
 802                 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 803         } endfor_nexthops(fi);
 804 }
 805 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 806
 807 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 808                        int remaining, struct fib_config *cfg,
 809                        struct netlink_ext_ack *extack)
 810 {
 811         NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 812
 813         return -EINVAL;
 814 }
 815
 816 #define fib_rebalance(fi) do { } while (0)
 817
 818 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 819
 820 static int fib_encap_match(struct net *net, u16 encap_type,
 821                            struct nlattr *encap,
 822                            const struct fib_nh *nh,
 823                            const struct fib_config *cfg,
 824                            struct netlink_ext_ack *extack)
 825 {
 826         struct lwtunnel_state *lwtstate;
 827         int ret, result = 0;
 828
 829         if (encap_type == LWTUNNEL_ENCAP_NONE)
 830                 return 0;
 831
 832         ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
 833                                    cfg, &lwtstate, extack);
 834         if (!ret) {
 835                 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 836                 lwtstate_free(lwtstate);
 837         }
 838
 839         return result;
 840 }
 841
 842 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
 843                  struct netlink_ext_ack *extack)
 844 {
 845 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 846         struct rtnexthop *rtnh;
 847         int remaining;
 848 #endif
 849
 850         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 851                 return 1;
 852
 853         if (cfg->fc_nh_id) {
 854                 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 855                         return 0;
 856                 return 1;
 857         }
 858
 859         if (cfg->fc_oif || cfg->fc_gw_family) {
 860                 struct fib_nh *nh = fib_info_nh(fi, 0);
 861
 862                 if (cfg->fc_encap) {
 863                         if (fib_encap_match(net, cfg->fc_encap_type,
 864                                             cfg->fc_encap, nh, cfg, extack))
 865                                 return 1;
 866                 }
 867 #ifdef CONFIG_IP_ROUTE_CLASSID
 868                 if (cfg->fc_flow &&
 869                     cfg->fc_flow != nh->nh_tclassid)
 870                         return 1;
 871 #endif
 872                 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 873                     (cfg->fc_gw_family &&
 874                      cfg->fc_gw_family != nh->fib_nh_gw_family))
 875                         return 1;
 876
 877                 if (cfg->fc_gw_family == AF_INET &&
 878                     cfg->fc_gw4 != nh->fib_nh_gw4)
 879                         return 1;
 880
 881                 if (cfg->fc_gw_family == AF_INET6 &&
 882                     ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 883                         return 1;
 884
 885                 return 0;
 886         }
 887
 888 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 889         if (!cfg->fc_mp)
 890                 return 0;
 891
 892         rtnh = cfg->fc_mp;
 893         remaining = cfg->fc_mp_len;
 894
 895         for_nexthops(fi) {
 896                 int attrlen;
 897
 898                 if (!rtnh_ok(rtnh, remaining))
 899                         return -EINVAL;
 900
 901                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 902                         return 1;
 903
 904                 attrlen = rtnh_attrlen(rtnh);
 905                 if (attrlen > 0) {
 906                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 907
 908                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 909                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 910                         if (nla && nlav) {
 911                                 NL_SET_ERR_MSG(extack,
 912                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 913                                 return -EINVAL;
 914                         }
 915
 916                         if (nla) {
 917                                 if (nh->fib_nh_gw_family != AF_INET ||
 918                                     nla_get_in_addr(nla) != nh->fib_nh_gw4)
 919                                         return 1;
 920                         } else if (nlav) {
 921                                 struct fib_config cfg2;
 922                                 int err;
 923
 924                                 err = fib_gw_from_via(&cfg2, nlav, extack);
 925                                 if (err)
 926                                         return err;
 927
 928                                 switch (nh->fib_nh_gw_family) {
 929                                 case AF_INET:
 930                                         if (cfg2.fc_gw_family != AF_INET ||
 931                                             cfg2.fc_gw4 != nh->fib_nh_gw4)
 932                                                 return 1;
 933                                         break;
 934                                 case AF_INET6:
 935                                         if (cfg2.fc_gw_family != AF_INET6 ||
 936                                             ipv6_addr_cmp(&cfg2.fc_gw6,
 937                                                           &nh->fib_nh_gw6))
 938                                                 return 1;
 939                                         break;
 940                                 }
 941                         }
 942
 943 #ifdef CONFIG_IP_ROUTE_CLASSID
 944                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 945                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 946                                 return 1;
 947 #endif
 948                 }
 949
 950                 rtnh = rtnh_next(rtnh, &remaining);
 951         } endfor_nexthops(fi);
 952 #endif
 953         return 0;
 954 }
 955
 956 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 957 {
 958         struct nlattr *nla;
 959         int remaining;
 960
 961         if (!cfg->fc_mx)
 962                 return true;
 963
 964         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 965                 int type = nla_type(nla);
 966                 u32 fi_val, val;
 967
 968                 if (!type)
 969                         continue;
 970                 if (type > RTAX_MAX)
 971                         return false;
 972
 973                 if (type == RTAX_CC_ALGO) {
 974                         char tmp[TCP_CA_NAME_MAX];
 975                         bool ecn_ca = false;
 976
 977                         nla_strscpy(tmp, nla, sizeof(tmp));
 978                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 979                 } else {
 980                         if (nla_len(nla) != sizeof(u32))
 981                                 return false;
 982                         val = nla_get_u32(nla);
 983                 }
 984
 985                 fi_val = fi->fib_metrics->metrics[type - 1];
 986                 if (type == RTAX_FEATURES)
 987                         fi_val &= ~DST_FEATURE_ECN_CA;
 988
 989                 if (fi_val != val)
 990                         return false;
 991         }
 992
 993         return true;
 994 }
 995
 996 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
 997                               u32 table, struct netlink_ext_ack *extack)
 998 {
 999         struct fib6_config cfg = {
1000                 .fc_table = table,
1001                 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1002                 .fc_ifindex = nh->fib_nh_oif,
1003                 .fc_gateway = nh->fib_nh_gw6,
1004         };
1005         struct fib6_nh fib6_nh = {};
1006         int err;
1007
1008         err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1009         if (!err) {
1010                 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1011                 dev_hold(nh->fib_nh_dev);
1012                 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1013                 nh->fib_nh_scope = RT_SCOPE_LINK;
1014
1015                 ipv6_stub->fib6_nh_release(&fib6_nh);
1016         }
1017
1018         return err;
1019 }
1020
1021 /*
1022  * Picture
1023  * -------
1024  *
1025  * Semantics of nexthop is very messy by historical reasons.
1026  * We have to take into account, that:
1027  * a) gateway can be actually local interface address,
1028  *    so that gatewayed route is direct.
1029  * b) gateway must be on-link address, possibly
1030  *    described not by an ifaddr, but also by a direct route.
1031  * c) If both gateway and interface are specified, they should not
1032  *    contradict.
1033  * d) If we use tunnel routes, gateway could be not on-link.
1034  *
1035  * Attempt to reconcile all of these (alas, self-contradictory) conditions
1036  * results in pretty ugly and hairy code with obscure logic.
1037  *
1038  * I chose to generalized it instead, so that the size
1039  * of code does not increase practically, but it becomes
1040  * much more general.
1041  * Every prefix is assigned a "scope" value: "host" is local address,
1042  * "link" is direct route,
1043  * [ ... "site" ... "interior" ... ]
1044  * and "universe" is true gateway route with global meaning.
1045  *
1046  * Every prefix refers to a set of "nexthop"s (gw, oif),
1047  * where gw must have narrower scope. This recursion stops
1048  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1049  * which means that gw is forced to be on link.
1050  *
1051  * Code is still hairy, but now it is apparently logically
1052  * consistent and very flexible. F.e. as by-product it allows
1053  * to co-exists in peace independent exterior and interior
1054  * routing processes.
1055  *
1056  * Normally it looks as following.
1057  *
1058  * {universe prefix}  -> (gw, oif) [scope link]
1059  *                |
1060  *                |-> {link prefix} -> (gw, oif) [scope local]
1061  *                                      |
1062  *                                      |-> {local prefix} (terminal node)
1063  */
1064 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1065                               u8 scope, struct netlink_ext_ack *extack)
1066 {
1067         struct net_device *dev;
1068         struct fib_result res;
1069         int err = 0;
1070
1071         if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1072                 unsigned int addr_type;
1073
1074                 if (scope >= RT_SCOPE_LINK) {
1075                         NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1076                         return -EINVAL;
1077                 }
1078                 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1079                 if (!dev) {
1080                         NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1081                         return -ENODEV;
1082                 }
1083                 if (!(dev->flags & IFF_UP)) {
1084                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1085                         return -ENETDOWN;
1086                 }
1087                 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1088                 if (addr_type != RTN_UNICAST) {
1089                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1090                         return -EINVAL;
1091                 }
1092                 if (!netif_carrier_ok(dev))
1093                         nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1094                 nh->fib_nh_dev = dev;
1095                 dev_hold(dev);
1096                 nh->fib_nh_scope = RT_SCOPE_LINK;
1097                 return 0;
1098         }
1099         rcu_read_lock();
1100         {
1101                 struct fib_table *tbl = NULL;
1102                 struct flowi4 fl4 = {
1103                         .daddr = nh->fib_nh_gw4,
1104                         .flowi4_scope = scope + 1,
1105                         .flowi4_oif = nh->fib_nh_oif,
1106                         .flowi4_iif = LOOPBACK_IFINDEX,
1107                 };
1108
1109                 /* It is not necessary, but requires a bit of thinking */
1110                 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1111                         fl4.flowi4_scope = RT_SCOPE_LINK;
1112
1113                 if (table && table != RT_TABLE_MAIN)
1114                         tbl = fib_get_table(net, table);
1115
1116                 if (tbl)
1117                         err = fib_table_lookup(tbl, &fl4, &res,
1118                                                FIB_LOOKUP_IGNORE_LINKSTATE |
1119                                                FIB_LOOKUP_NOREF);
1120
1121                 /* on error or if no table given do full lookup. This
1122                  * is needed for example when nexthops are in the local
1123                  * table rather than the given table
1124                  */
1125                 if (!tbl || err) {
1126                         err = fib_lookup(net, &fl4, &res,
1127                                          FIB_LOOKUP_IGNORE_LINKSTATE);
1128                 }
1129
1130                 if (err) {
1131                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1132                         goto out;
1133                 }
1134         }
1135
1136         err = -EINVAL;
1137         if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1138                 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139                 goto out;
1140         }
1141         nh->fib_nh_scope = res.scope;
1142         nh->fib_nh_oif = FIB_RES_OIF(res);
1143         nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1144         if (!dev) {
1145                 NL_SET_ERR_MSG(extack,
1146                                "No egress device for nexthop gateway");
1147                 goto out;
1148         }
1149         dev_hold(dev);
1150         if (!netif_carrier_ok(dev))
1151                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1152         err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1153 out:
1154         rcu_read_unlock();
1155         return err;
1156 }
1157
1158 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1159                               struct netlink_ext_ack *extack)
1160 {
1161         struct in_device *in_dev;
1162         int err;
1163
1164         if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1165                 NL_SET_ERR_MSG(extack,
1166                                "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1167                 return -EINVAL;
1168         }
1169
1170         rcu_read_lock();
1171
1172         err = -ENODEV;
1173         in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1174         if (!in_dev)
1175                 goto out;
1176         err = -ENETDOWN;
1177         if (!(in_dev->dev->flags & IFF_UP)) {
1178                 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1179                 goto out;
1180         }
1181
1182         nh->fib_nh_dev = in_dev->dev;
1183         dev_hold(nh->fib_nh_dev);
1184         nh->fib_nh_scope = RT_SCOPE_HOST;
1185         if (!netif_carrier_ok(nh->fib_nh_dev))
1186                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1187         err = 0;
1188 out:
1189         rcu_read_unlock();
1190         return err;
1191 }
1192
1193 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1194                  struct netlink_ext_ack *extack)
1195 {
1196         int err;
1197
1198         if (nh->fib_nh_gw_family == AF_INET)
1199                 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1200         else if (nh->fib_nh_gw_family == AF_INET6)
1201                 err = fib_check_nh_v6_gw(net, nh, table, extack);
1202         else
1203                 err = fib_check_nh_nongw(net, nh, extack);
1204
1205         return err;
1206 }
1207
1208 static inline unsigned int fib_laddr_hashfn(__be32 val)
1209 {
1210         unsigned int mask = (fib_info_hash_size - 1);
1211
1212         return ((__force u32)val ^
1213                 ((__force u32)val >> 7) ^
1214                 ((__force u32)val >> 14)) & mask;
1215 }
1216
1217 static struct hlist_head *fib_info_hash_alloc(int bytes)
1218 {
1219         if (bytes <= PAGE_SIZE)
1220                 return kzalloc(bytes, GFP_KERNEL);
1221         else
1222                 return (struct hlist_head *)
1223                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1224                                          get_order(bytes));
1225 }
1226
1227 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1228 {
1229         if (!hash)
1230                 return;
1231
1232         if (bytes <= PAGE_SIZE)
1233                 kfree(hash);
1234         else
1235                 free_pages((unsigned long) hash, get_order(bytes));
1236 }
1237
1238 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1239                                struct hlist_head *new_laddrhash,
1240                                unsigned int new_size)
1241 {
1242         struct hlist_head *old_info_hash, *old_laddrhash;
1243         unsigned int old_size = fib_info_hash_size;
1244         unsigned int i, bytes;
1245
1246         spin_lock_bh(&fib_info_lock);
1247         old_info_hash = fib_info_hash;
1248         old_laddrhash = fib_info_laddrhash;
1249         fib_info_hash_size = new_size;
1250
1251         for (i = 0; i < old_size; i++) {
1252                 struct hlist_head *head = &fib_info_hash[i];
1253                 struct hlist_node *n;
1254                 struct fib_info *fi;
1255
1256                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1257                         struct hlist_head *dest;
1258                         unsigned int new_hash;
1259
1260                         new_hash = fib_info_hashfn(fi);
1261                         dest = &new_info_hash[new_hash];
1262                         hlist_add_head(&fi->fib_hash, dest);
1263                 }
1264         }
1265         fib_info_hash = new_info_hash;
1266
1267         for (i = 0; i < old_size; i++) {
1268                 struct hlist_head *lhead = &fib_info_laddrhash[i];
1269                 struct hlist_node *n;
1270                 struct fib_info *fi;
1271
1272                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1273                         struct hlist_head *ldest;
1274                         unsigned int new_hash;
1275
1276                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1277                         ldest = &new_laddrhash[new_hash];
1278                         hlist_add_head(&fi->fib_lhash, ldest);
1279                 }
1280         }
1281         fib_info_laddrhash = new_laddrhash;
1282
1283         spin_unlock_bh(&fib_info_lock);
1284
1285         bytes = old_size * sizeof(struct hlist_head *);
1286         fib_info_hash_free(old_info_hash, bytes);
1287         fib_info_hash_free(old_laddrhash, bytes);
1288 }
1289
1290 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1291                                  unsigned char scope)
1292 {
1293         struct fib_nh *nh;
1294
1295         if (nhc->nhc_family != AF_INET)
1296                 return inet_select_addr(nhc->nhc_dev, 0, scope);
1297
1298         nh = container_of(nhc, struct fib_nh, nh_common);
1299         nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1300         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1301
1302         return nh->nh_saddr;
1303 }
1304
1305 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1306 {
1307         struct fib_nh_common *nhc = res->nhc;
1308
1309         if (res->fi->fib_prefsrc)
1310                 return res->fi->fib_prefsrc;
1311
1312         if (nhc->nhc_family == AF_INET) {
1313                 struct fib_nh *nh;
1314
1315                 nh = container_of(nhc, struct fib_nh, nh_common);
1316                 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1317                         return nh->nh_saddr;
1318         }
1319
1320         return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1321 }
1322
1323 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1324 {
1325         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1326             fib_prefsrc != cfg->fc_dst) {
1327                 u32 tb_id = cfg->fc_table;
1328                 int rc;
1329
1330                 if (tb_id == RT_TABLE_MAIN)
1331                         tb_id = RT_TABLE_LOCAL;
1332
1333                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1334                                           fib_prefsrc, tb_id);
1335
1336                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1337                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1338                                                   fib_prefsrc, RT_TABLE_LOCAL);
1339                 }
1340
1341                 if (rc != RTN_LOCAL)
1342                         return false;
1343         }
1344         return true;
1345 }
1346
1347 struct fib_info *fib_create_info(struct fib_config *cfg,
1348                                  struct netlink_ext_ack *extack)
1349 {
1350         int err;
1351         struct fib_info *fi = NULL;
1352         struct nexthop *nh = NULL;
1353         struct fib_info *ofi;
1354         int nhs = 1;
1355         struct net *net = cfg->fc_nlinfo.nl_net;
1356
1357         if (cfg->fc_type > RTN_MAX)
1358                 goto err_inval;
1359
1360         /* Fast check to catch the most weird cases */
1361         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1362                 NL_SET_ERR_MSG(extack, "Invalid scope");
1363                 goto err_inval;
1364         }
1365
1366         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1367                 NL_SET_ERR_MSG(extack,
1368                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1369                 goto err_inval;
1370         }
1371
1372         if (cfg->fc_nh_id) {
1373                 if (!cfg->fc_mx) {
1374                         fi = fib_find_info_nh(net, cfg);
1375                         if (fi) {
1376                                 fi->fib_treeref++;
1377                                 return fi;
1378                         }
1379                 }
1380
1381                 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1382                 if (!nh) {
1383                         NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1384                         goto err_inval;
1385                 }
1386                 nhs = 0;
1387         }
1388
1389 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1390         if (cfg->fc_mp) {
1391                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1392                 if (nhs == 0)
1393                         goto err_inval;
1394         }
1395 #endif
1396
1397         err = -ENOBUFS;
1398         if (fib_info_cnt >= fib_info_hash_size) {
1399                 unsigned int new_size = fib_info_hash_size << 1;
1400                 struct hlist_head *new_info_hash;
1401                 struct hlist_head *new_laddrhash;
1402                 unsigned int bytes;
1403
1404                 if (!new_size)
1405                         new_size = 16;
1406                 bytes = new_size * sizeof(struct hlist_head *);
1407                 new_info_hash = fib_info_hash_alloc(bytes);
1408                 new_laddrhash = fib_info_hash_alloc(bytes);
1409                 if (!new_info_hash || !new_laddrhash) {
1410                         fib_info_hash_free(new_info_hash, bytes);
1411                         fib_info_hash_free(new_laddrhash, bytes);
1412                 } else
1413                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1414
1415                 if (!fib_info_hash_size)
1416                         goto failure;
1417         }
1418
1419         fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1420         if (!fi)
1421                 goto failure;
1422         fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1423                                               cfg->fc_mx_len, extack);
1424         if (IS_ERR(fi->fib_metrics)) {
1425                 err = PTR_ERR(fi->fib_metrics);
1426                 kfree(fi);
1427                 return ERR_PTR(err);
1428         }
1429
1430         fib_info_cnt++;
1431         fi->fib_net = net;
1432         fi->fib_protocol = cfg->fc_protocol;
1433         fi->fib_scope = cfg->fc_scope;
1434         fi->fib_flags = cfg->fc_flags;
1435         fi->fib_priority = cfg->fc_priority;
1436         fi->fib_prefsrc = cfg->fc_prefsrc;
1437         fi->fib_type = cfg->fc_type;
1438         fi->fib_tb_id = cfg->fc_table;
1439
1440         fi->fib_nhs = nhs;
1441         if (nh) {
1442                 if (!nexthop_get(nh)) {
1443                         NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1444                         err = -EINVAL;
1445                 } else {
1446                         err = 0;
1447                         fi->nh = nh;
1448                 }
1449         } else {
1450                 change_nexthops(fi) {
1451                         nexthop_nh->nh_parent = fi;
1452                 } endfor_nexthops(fi)
1453
1454                 if (cfg->fc_mp)
1455                         err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1456                                           extack);
1457                 else
1458                         err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1459         }
1460
1461         if (err != 0)
1462                 goto failure;
1463
1464         if (fib_props[cfg->fc_type].error) {
1465                 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1466                         NL_SET_ERR_MSG(extack,
1467                                        "Gateway, device and multipath can not be specified for this route type");
1468                         goto err_inval;
1469                 }
1470                 goto link_it;
1471         } else {
1472                 switch (cfg->fc_type) {
1473                 case RTN_UNICAST:
1474                 case RTN_LOCAL:
1475                 case RTN_BROADCAST:
1476                 case RTN_ANYCAST:
1477                 case RTN_MULTICAST:
1478                         break;
1479                 default:
1480                         NL_SET_ERR_MSG(extack, "Invalid route type");
1481                         goto err_inval;
1482                 }
1483         }
1484
1485         if (cfg->fc_scope > RT_SCOPE_HOST) {
1486                 NL_SET_ERR_MSG(extack, "Invalid scope");
1487                 goto err_inval;
1488         }
1489
1490         if (fi->nh) {
1491                 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1492                 if (err)
1493                         goto failure;
1494         } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1495                 struct fib_nh *nh = fi->fib_nh;
1496
1497                 /* Local address is added. */
1498                 if (nhs != 1) {
1499                         NL_SET_ERR_MSG(extack,
1500                                        "Route with host scope can not have multiple nexthops");
1501                         goto err_inval;
1502                 }
1503                 if (nh->fib_nh_gw_family) {
1504                         NL_SET_ERR_MSG(extack,
1505                                        "Route with host scope can not have a gateway");
1506                         goto err_inval;
1507                 }
1508                 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1509                 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1510                 err = -ENODEV;
1511                 if (!nh->fib_nh_dev)
1512                         goto failure;
1513         } else {
1514                 int linkdown = 0;
1515
1516                 change_nexthops(fi) {
1517                         err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1518                                            cfg->fc_table, cfg->fc_scope,
1519                                            extack);
1520                         if (err != 0)
1521                                 goto failure;
1522                         if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1523                                 linkdown++;
1524                 } endfor_nexthops(fi)
1525                 if (linkdown == fi->fib_nhs)
1526                         fi->fib_flags |= RTNH_F_LINKDOWN;
1527         }
1528
1529         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1530                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1531                 goto err_inval;
1532         }
1533
1534         if (!fi->nh) {
1535                 change_nexthops(fi) {
1536                         fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1537                                                   fi->fib_scope);
1538                         if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1539                                 fi->fib_nh_is_v6 = true;
1540                 } endfor_nexthops(fi)
1541
1542                 fib_rebalance(fi);
1543         }
1544
1545 link_it:
1546         ofi = fib_find_info(fi);
1547         if (ofi) {
1548                 fi->fib_dead = 1;
1549                 free_fib_info(fi);
1550                 ofi->fib_treeref++;
1551                 return ofi;
1552         }
1553
1554         fi->fib_treeref++;
1555         refcount_set(&fi->fib_clntref, 1);
1556         spin_lock_bh(&fib_info_lock);
1557         hlist_add_head(&fi->fib_hash,
1558                        &fib_info_hash[fib_info_hashfn(fi)]);
1559         if (fi->fib_prefsrc) {
1560                 struct hlist_head *head;
1561
1562                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1563                 hlist_add_head(&fi->fib_lhash, head);
1564         }
1565         if (fi->nh) {
1566                 list_add(&fi->nh_list, &nh->fi_list);
1567         } else {
1568                 change_nexthops(fi) {
1569                         struct hlist_head *head;
1570                         unsigned int hash;
1571
1572                         if (!nexthop_nh->fib_nh_dev)
1573                                 continue;
1574                         hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1575                         head = &fib_info_devhash[hash];
1576                         hlist_add_head(&nexthop_nh->nh_hash, head);
1577                 } endfor_nexthops(fi)
1578         }
1579         spin_unlock_bh(&fib_info_lock);
1580         return fi;
1581
1582 err_inval:
1583         err = -EINVAL;
1584
1585 failure:
1586         if (fi) {
1587                 fi->fib_dead = 1;
1588                 free_fib_info(fi);
1589         }
1590
1591         return ERR_PTR(err);
1592 }
1593
1594 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1595                      u8 rt_family, unsigned char *flags, bool skip_oif)
1596 {
1597         if (nhc->nhc_flags & RTNH_F_DEAD)
1598                 *flags |= RTNH_F_DEAD;
1599
1600         if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1601                 *flags |= RTNH_F_LINKDOWN;
1602
1603                 rcu_read_lock();
1604                 switch (nhc->nhc_family) {
1605                 case AF_INET:
1606                         if (ip_ignore_linkdown(nhc->nhc_dev))
1607                                 *flags |= RTNH_F_DEAD;
1608                         break;
1609                 case AF_INET6:
1610                         if (ip6_ignore_linkdown(nhc->nhc_dev))
1611                                 *flags |= RTNH_F_DEAD;
1612                         break;
1613                 }
1614                 rcu_read_unlock();
1615         }
1616
1617         switch (nhc->nhc_gw_family) {
1618         case AF_INET:
1619                 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1620                         goto nla_put_failure;
1621                 break;
1622         case AF_INET6:
1623                 /* if gateway family does not match nexthop family
1624                  * gateway is encoded as RTA_VIA
1625                  */
1626                 if (rt_family != nhc->nhc_gw_family) {
1627                         int alen = sizeof(struct in6_addr);
1628                         struct nlattr *nla;
1629                         struct rtvia *via;
1630
1631                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
1632                         if (!nla)
1633                                 goto nla_put_failure;
1634
1635                         via = nla_data(nla);
1636                         via->rtvia_family = AF_INET6;
1637                         memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1638                 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1639                                             &nhc->nhc_gw.ipv6) < 0) {
1640                         goto nla_put_failure;
1641                 }
1642                 break;
1643         }
1644
1645         *flags |= (nhc->nhc_flags &
1646                    (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1647
1648         if (!skip_oif && nhc->nhc_dev &&
1649             nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1650                 goto nla_put_failure;
1651
1652         if (nhc->nhc_lwtstate &&
1653             lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1654                                 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1655                 goto nla_put_failure;
1656
1657         return 0;
1658
1659 nla_put_failure:
1660         return -EMSGSIZE;
1661 }
1662 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1663
1664 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1665 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1666                     int nh_weight, u8 rt_family)
1667 {
1668         const struct net_device *dev = nhc->nhc_dev;
1669         struct rtnexthop *rtnh;
1670         unsigned char flags = 0;
1671
1672         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1673         if (!rtnh)
1674                 goto nla_put_failure;
1675
1676         rtnh->rtnh_hops = nh_weight - 1;
1677         rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1678
1679         if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1680                 goto nla_put_failure;
1681
1682         rtnh->rtnh_flags = flags;
1683
1684         /* length of rtnetlink header + attributes */
1685         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1686
1687         return 0;
1688
1689 nla_put_failure:
1690         return -EMSGSIZE;
1691 }
1692 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1693 #endif
1694
1695 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1696 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1697 {
1698         struct nlattr *mp;
1699
1700         mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1701         if (!mp)
1702                 goto nla_put_failure;
1703
1704         if (unlikely(fi->nh)) {
1705                 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1706                         goto nla_put_failure;
1707                 goto mp_end;
1708         }
1709
1710         for_nexthops(fi) {
1711                 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1712                                     AF_INET) < 0)
1713                         goto nla_put_failure;
1714 #ifdef CONFIG_IP_ROUTE_CLASSID
1715                 if (nh->nh_tclassid &&
1716                     nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1717                         goto nla_put_failure;
1718 #endif
1719         } endfor_nexthops(fi);
1720
1721 mp_end:
1722         nla_nest_end(skb, mp);
1723
1724         return 0;
1725
1726 nla_put_failure:
1727         return -EMSGSIZE;
1728 }
1729 #else
1730 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1731 {
1732         return 0;
1733 }
1734 #endif
1735
1736 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1737                   const struct fib_rt_info *fri, unsigned int flags)
1738 {
1739         unsigned int nhs = fib_info_num_path(fri->fi);
1740         struct fib_info *fi = fri->fi;
1741         u32 tb_id = fri->tb_id;
1742         struct nlmsghdr *nlh;
1743         struct rtmsg *rtm;
1744
1745         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1746         if (!nlh)
1747                 return -EMSGSIZE;
1748
1749         rtm = nlmsg_data(nlh);
1750         rtm->rtm_family = AF_INET;
1751         rtm->rtm_dst_len = fri->dst_len;
1752         rtm->rtm_src_len = 0;
1753         rtm->rtm_tos = fri->tos;
1754         if (tb_id < 256)
1755                 rtm->rtm_table = tb_id;
1756         else
1757                 rtm->rtm_table = RT_TABLE_COMPAT;
1758         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1759                 goto nla_put_failure;
1760         rtm->rtm_type = fri->type;
1761         rtm->rtm_flags = fi->fib_flags;
1762         rtm->rtm_scope = fi->fib_scope;
1763         rtm->rtm_protocol = fi->fib_protocol;
1764
1765         if (rtm->rtm_dst_len &&
1766             nla_put_in_addr(skb, RTA_DST, fri->dst))
1767                 goto nla_put_failure;
1768         if (fi->fib_priority &&
1769             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1770                 goto nla_put_failure;
1771         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1772                 goto nla_put_failure;
1773
1774         if (fi->fib_prefsrc &&
1775             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1776                 goto nla_put_failure;
1777
1778         if (fi->nh) {
1779                 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1780                         goto nla_put_failure;
1781                 if (nexthop_is_blackhole(fi->nh))
1782                         rtm->rtm_type = RTN_BLACKHOLE;
1783                 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1784                         goto offload;
1785         }
1786
1787         if (nhs == 1) {
1788                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1789                 unsigned char flags = 0;
1790
1791                 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1792                         goto nla_put_failure;
1793
1794                 rtm->rtm_flags = flags;
1795 #ifdef CONFIG_IP_ROUTE_CLASSID
1796                 if (nhc->nhc_family == AF_INET) {
1797                         struct fib_nh *nh;
1798
1799                         nh = container_of(nhc, struct fib_nh, nh_common);
1800                         if (nh->nh_tclassid &&
1801                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1802                                 goto nla_put_failure;
1803                 }
1804 #endif
1805         } else {
1806                 if (fib_add_multipath(skb, fi) < 0)
1807                         goto nla_put_failure;
1808         }
1809
1810 offload:
1811         if (fri->offload)
1812                 rtm->rtm_flags |= RTM_F_OFFLOAD;
1813         if (fri->trap)
1814                 rtm->rtm_flags |= RTM_F_TRAP;
1815         if (fri->offload_failed)
1816                 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1817
1818         nlmsg_end(skb, nlh);
1819         return 0;
1820
1821 nla_put_failure:
1822         nlmsg_cancel(skb, nlh);
1823         return -EMSGSIZE;
1824 }
1825
1826 /*
1827  * Update FIB if:
1828  * - local address disappeared -> we must delete all the entries
1829  *   referring to it.
1830  * - device went down -> we must shutdown all nexthops going via it.
1831  */
1832 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1833 {
1834         int ret = 0;
1835         unsigned int hash = fib_laddr_hashfn(local);
1836         struct hlist_head *head = &fib_info_laddrhash[hash];
1837         int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1838         struct net *net = dev_net(dev);
1839         struct fib_info *fi;
1840
1841         if (!fib_info_laddrhash || local == 0)
1842                 return 0;
1843
1844         hlist_for_each_entry(fi, head, fib_lhash) {
1845                 if (!net_eq(fi->fib_net, net) ||
1846                     fi->fib_tb_id != tb_id)
1847                         continue;
1848                 if (fi->fib_prefsrc == local) {
1849                         fi->fib_flags |= RTNH_F_DEAD;
1850                         ret++;
1851                 }
1852         }
1853         return ret;
1854 }
1855
1856 static int call_fib_nh_notifiers(struct fib_nh *nh,
1857                                  enum fib_event_type event_type)
1858 {
1859         bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1860         struct fib_nh_notifier_info info = {
1861                 .fib_nh = nh,
1862         };
1863
1864         switch (event_type) {
1865         case FIB_EVENT_NH_ADD:
1866                 if (nh->fib_nh_flags & RTNH_F_DEAD)
1867                         break;
1868                 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1869                         break;
1870                 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1871                                            &info.info);
1872         case FIB_EVENT_NH_DEL:
1873                 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1874                     (nh->fib_nh_flags & RTNH_F_DEAD))
1875                         return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1876                                                    event_type, &info.info);
1877         default:
1878                 break;
1879         }
1880
1881         return NOTIFY_DONE;
1882 }
1883
1884 /* Update the PMTU of exceptions when:
1885  * - the new MTU of the first hop becomes smaller than the PMTU
1886  * - the old MTU was the same as the PMTU, and it limited discovery of
1887  *   larger MTUs on the path. With that limit raised, we can now
1888  *   discover larger MTUs
1889  * A special case is locked exceptions, for which the PMTU is smaller
1890  * than the minimal accepted PMTU:
1891  * - if the new MTU is greater than the PMTU, don't make any change
1892  * - otherwise, unlock and set PMTU
1893  */
1894 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1895 {
1896         struct fnhe_hash_bucket *bucket;
1897         int i;
1898
1899         bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1900         if (!bucket)
1901                 return;
1902
1903         for (i = 0; i < FNHE_HASH_SIZE; i++) {
1904                 struct fib_nh_exception *fnhe;
1905
1906                 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1907                      fnhe;
1908                      fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1909                         if (fnhe->fnhe_mtu_locked) {
1910                                 if (new <= fnhe->fnhe_pmtu) {
1911                                         fnhe->fnhe_pmtu = new;
1912                                         fnhe->fnhe_mtu_locked = false;
1913                                 }
1914                         } else if (new < fnhe->fnhe_pmtu ||
1915                                    orig == fnhe->fnhe_pmtu) {
1916                                 fnhe->fnhe_pmtu = new;
1917                         }
1918                 }
1919         }
1920 }
1921
1922 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1923 {
1924         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1925         struct hlist_head *head = &fib_info_devhash[hash];
1926         struct fib_nh *nh;
1927
1928         hlist_for_each_entry(nh, head, nh_hash) {
1929                 if (nh->fib_nh_dev == dev)
1930                         fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1931         }
1932 }
1933
1934 /* Event              force Flags           Description
1935  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1936  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1937  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1938  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1939  *
1940  * only used when fib_nh is built into fib_info
1941  */
1942 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1943 {
1944         int ret = 0;
1945         int scope = RT_SCOPE_NOWHERE;
1946         struct fib_info *prev_fi = NULL;
1947         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1948         struct hlist_head *head = &fib_info_devhash[hash];
1949         struct fib_nh *nh;
1950
1951         if (force)
1952                 scope = -1;
1953
1954         hlist_for_each_entry(nh, head, nh_hash) {
1955                 struct fib_info *fi = nh->nh_parent;
1956                 int dead;
1957
1958                 BUG_ON(!fi->fib_nhs);
1959                 if (nh->fib_nh_dev != dev || fi == prev_fi)
1960                         continue;
1961                 prev_fi = fi;
1962                 dead = 0;
1963                 change_nexthops(fi) {
1964                         if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1965                                 dead++;
1966                         else if (nexthop_nh->fib_nh_dev == dev &&
1967                                  nexthop_nh->fib_nh_scope != scope) {
1968                                 switch (event) {
1969                                 case NETDEV_DOWN:
1970                                 case NETDEV_UNREGISTER:
1971                                         nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1972                                         fallthrough;
1973                                 case NETDEV_CHANGE:
1974                                         nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1975                                         break;
1976                                 }
1977                                 call_fib_nh_notifiers(nexthop_nh,
1978                                                       FIB_EVENT_NH_DEL);
1979                                 dead++;
1980                         }
1981 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1982                         if (event == NETDEV_UNREGISTER &&
1983                             nexthop_nh->fib_nh_dev == dev) {
1984                                 dead = fi->fib_nhs;
1985                                 break;
1986                         }
1987 #endif
1988                 } endfor_nexthops(fi)
1989                 if (dead == fi->fib_nhs) {
1990                         switch (event) {
1991                         case NETDEV_DOWN:
1992                         case NETDEV_UNREGISTER:
1993                                 fi->fib_flags |= RTNH_F_DEAD;
1994                                 fallthrough;
1995                         case NETDEV_CHANGE:
1996                                 fi->fib_flags |= RTNH_F_LINKDOWN;
1997                                 break;
1998                         }
1999                         ret++;
2000                 }
2001
2002                 fib_rebalance(fi);
2003         }
2004
2005         return ret;
2006 }
2007
2008 /* Must be invoked inside of an RCU protected region.  */
2009 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2010 {
2011         struct fib_info *fi = NULL, *last_resort = NULL;
2012         struct hlist_head *fa_head = res->fa_head;
2013         struct fib_table *tb = res->table;
2014         u8 slen = 32 - res->prefixlen;
2015         int order = -1, last_idx = -1;
2016         struct fib_alias *fa, *fa1 = NULL;
2017         u32 last_prio = res->fi->fib_priority;
2018         u8 last_tos = 0;
2019
2020         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2021                 struct fib_info *next_fi = fa->fa_info;
2022                 struct fib_nh_common *nhc;
2023
2024                 if (fa->fa_slen != slen)
2025                         continue;
2026                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2027                         continue;
2028                 if (fa->tb_id != tb->tb_id)
2029                         continue;
2030                 if (next_fi->fib_priority > last_prio &&
2031                     fa->fa_tos == last_tos) {
2032                         if (last_tos)
2033                                 continue;
2034                         break;
2035                 }
2036                 if (next_fi->fib_flags & RTNH_F_DEAD)
2037                         continue;
2038                 last_tos = fa->fa_tos;
2039                 last_prio = next_fi->fib_priority;
2040
2041                 if (next_fi->fib_scope != res->scope ||
2042                     fa->fa_type != RTN_UNICAST)
2043                         continue;
2044
2045                 nhc = fib_info_nhc(next_fi, 0);
2046                 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2047                         continue;
2048
2049                 fib_alias_accessed(fa);
2050
2051                 if (!fi) {
2052                         if (next_fi != res->fi)
2053                                 break;
2054                         fa1 = fa;
2055                 } else if (!fib_detect_death(fi, order, &last_resort,
2056                                              &last_idx, fa1->fa_default)) {
2057                         fib_result_assign(res, fi);
2058                         fa1->fa_default = order;
2059                         goto out;
2060                 }
2061                 fi = next_fi;
2062                 order++;
2063         }
2064
2065         if (order <= 0 || !fi) {
2066                 if (fa1)
2067                         fa1->fa_default = -1;
2068                 goto out;
2069         }
2070
2071         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2072                               fa1->fa_default)) {
2073                 fib_result_assign(res, fi);
2074                 fa1->fa_default = order;
2075                 goto out;
2076         }
2077
2078         if (last_idx >= 0)
2079                 fib_result_assign(res, last_resort);
2080         fa1->fa_default = last_idx;
2081 out:
2082         return;
2083 }
2084
2085 /*
2086  * Dead device goes up. We wake up dead nexthops.
2087  * It takes sense only on multipath routes.
2088  *
2089  * only used when fib_nh is built into fib_info
2090  */
2091 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2092 {
2093         struct fib_info *prev_fi;
2094         unsigned int hash;
2095         struct hlist_head *head;
2096         struct fib_nh *nh;
2097         int ret;
2098
2099         if (!(dev->flags & IFF_UP))
2100                 return 0;
2101
2102         if (nh_flags & RTNH_F_DEAD) {
2103                 unsigned int flags = dev_get_flags(dev);
2104
2105                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2106                         nh_flags |= RTNH_F_LINKDOWN;
2107         }
2108
2109         prev_fi = NULL;
2110         hash = fib_devindex_hashfn(dev->ifindex);
2111         head = &fib_info_devhash[hash];
2112         ret = 0;
2113
2114         hlist_for_each_entry(nh, head, nh_hash) {
2115                 struct fib_info *fi = nh->nh_parent;
2116                 int alive;
2117
2118                 BUG_ON(!fi->fib_nhs);
2119                 if (nh->fib_nh_dev != dev || fi == prev_fi)
2120                         continue;
2121
2122                 prev_fi = fi;
2123                 alive = 0;
2124                 change_nexthops(fi) {
2125                         if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2126                                 alive++;
2127                                 continue;
2128                         }
2129                         if (!nexthop_nh->fib_nh_dev ||
2130                             !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2131                                 continue;
2132                         if (nexthop_nh->fib_nh_dev != dev ||
2133                             !__in_dev_get_rtnl(dev))
2134                                 continue;
2135                         alive++;
2136                         nexthop_nh->fib_nh_flags &= ~nh_flags;
2137                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2138                 } endfor_nexthops(fi)
2139
2140                 if (alive > 0) {
2141                         fi->fib_flags &= ~nh_flags;
2142                         ret++;
2143                 }
2144
2145                 fib_rebalance(fi);
2146         }
2147
2148         return ret;
2149 }
2150
2151 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2152 static bool fib_good_nh(const struct fib_nh *nh)
2153 {
2154         int state = NUD_REACHABLE;
2155
2156         if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2157                 struct neighbour *n;
2158
2159                 rcu_read_lock_bh();
2160
2161                 if (likely(nh->fib_nh_gw_family == AF_INET))
2162                         n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2163                                                    (__force u32)nh->fib_nh_gw4);
2164                 else if (nh->fib_nh_gw_family == AF_INET6)
2165                         n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2166                                                            &nh->fib_nh_gw6);
2167                 else
2168                         n = NULL;
2169                 if (n)
2170                         state = n->nud_state;
2171
2172                 rcu_read_unlock_bh();
2173         }
2174
2175         return !!(state & NUD_VALID);
2176 }
2177
2178 void fib_select_multipath(struct fib_result *res, int hash)
2179 {
2180         struct fib_info *fi = res->fi;
2181         struct net *net = fi->fib_net;
2182         bool first = false;
2183
2184         if (unlikely(res->fi->nh)) {
2185                 nexthop_path_fib_result(res, hash);
2186                 return;
2187         }
2188
2189         change_nexthops(fi) {
2190                 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2191                         if (!fib_good_nh(nexthop_nh))
2192                                 continue;
2193                         if (!first) {
2194                                 res->nh_sel = nhsel;
2195                                 res->nhc = &nexthop_nh->nh_common;
2196                                 first = true;
2197                         }
2198                 }
2199
2200                 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2201                         continue;
2202
2203                 res->nh_sel = nhsel;
2204                 res->nhc = &nexthop_nh->nh_common;
2205                 return;
2206         } endfor_nexthops(fi);
2207 }
2208 #endif
2209
2210 void fib_select_path(struct net *net, struct fib_result *res,
2211                      struct flowi4 *fl4, const struct sk_buff *skb)
2212 {
2213         if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2214                 goto check_saddr;
2215
2216 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2217         if (fib_info_num_path(res->fi) > 1) {
2218                 int h = fib_multipath_hash(net, fl4, skb, NULL);
2219
2220                 fib_select_multipath(res, h);
2221         }
2222         else
2223 #endif
2224         if (!res->prefixlen &&
2225             res->table->tb_num_default > 1 &&
2226             res->type == RTN_UNICAST)
2227                 fib_select_default(fl4, res);
2228
2229 check_saddr:
2230         if (!fl4->saddr)
2231                 fl4->saddr = fib_result_prefsrc(net, res);
2232 }