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 #include <linux/hash.h>
  33
  34 #include <net/arp.h>
  35 #include <net/inet_dscp.h>
  36 #include <net/ip.h>
  37 #include <net/protocol.h>
  38 #include <net/route.h>
  39 #include <net/tcp.h>
  40 #include <net/sock.h>
  41 #include <net/ip_fib.h>
  42 #include <net/ip6_fib.h>
  43 #include <net/nexthop.h>
  44 #include <net/netlink.h>
  45 #include <net/rtnh.h>
  46 #include <net/lwtunnel.h>
  47 #include <net/fib_notifier.h>
  48 #include <net/addrconf.h>
  49
  50 #include "fib_lookup.h"
  51
  52 static DEFINE_SPINLOCK(fib_info_lock);
  53 static struct hlist_head *fib_info_hash;
  54 static struct hlist_head *fib_info_laddrhash;
  55 static unsigned int fib_info_hash_size;
  56 static unsigned int fib_info_hash_bits;
  57 static unsigned int fib_info_cnt;
  58
  59 #define DEVINDEX_HASHBITS 8
  60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  62
  63 /* for_nexthops and change_nexthops only used when nexthop object
  64  * is not set in a fib_info. The logic within can reference fib_nh.
  65  */
  66 #ifdef CONFIG_IP_ROUTE_MULTIPATH
  67
  68 #define for_nexthops(fi) {                                              \
  69         int nhsel; const struct fib_nh *nh;                             \
  70         for (nhsel = 0, nh = (fi)->fib_nh;                              \
  71              nhsel < fib_info_num_path((fi));                           \
  72              nh++, nhsel++)
  73
  74 #define change_nexthops(fi) {                                           \
  75         int nhsel; struct fib_nh *nexthop_nh;                           \
  76         for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh);   \
  77              nhsel < fib_info_num_path((fi));                           \
  78              nexthop_nh++, nhsel++)
  79
  80 #else /* CONFIG_IP_ROUTE_MULTIPATH */
  81
  82 /* Hope, that gcc will optimize it to get rid of dummy loop */
  83
  84 #define for_nexthops(fi) {                                              \
  85         int nhsel; const struct fib_nh *nh = (fi)->fib_nh;              \
  86         for (nhsel = 0; nhsel < 1; nhsel++)
  87
  88 #define change_nexthops(fi) {                                           \
  89         int nhsel;                                                      \
  90         struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);    \
  91         for (nhsel = 0; nhsel < 1; nhsel++)
  92
  93 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
  94
  95 #define endfor_nexthops(fi) }
  96
  97
  98 const struct fib_prop fib_props[RTN_MAX + 1] = {
  99         [RTN_UNSPEC] = {
 100                 .error  = 0,
 101                 .scope  = RT_SCOPE_NOWHERE,
 102         },
 103         [RTN_UNICAST] = {
 104                 .error  = 0,
 105                 .scope  = RT_SCOPE_UNIVERSE,
 106         },
 107         [RTN_LOCAL] = {
 108                 .error  = 0,
 109                 .scope  = RT_SCOPE_HOST,
 110         },
 111         [RTN_BROADCAST] = {
 112                 .error  = 0,
 113                 .scope  = RT_SCOPE_LINK,
 114         },
 115         [RTN_ANYCAST] = {
 116                 .error  = 0,
 117                 .scope  = RT_SCOPE_LINK,
 118         },
 119         [RTN_MULTICAST] = {
 120                 .error  = 0,
 121                 .scope  = RT_SCOPE_UNIVERSE,
 122         },
 123         [RTN_BLACKHOLE] = {
 124                 .error  = -EINVAL,
 125                 .scope  = RT_SCOPE_UNIVERSE,
 126         },
 127         [RTN_UNREACHABLE] = {
 128                 .error  = -EHOSTUNREACH,
 129                 .scope  = RT_SCOPE_UNIVERSE,
 130         },
 131         [RTN_PROHIBIT] = {
 132                 .error  = -EACCES,
 133                 .scope  = RT_SCOPE_UNIVERSE,
 134         },
 135         [RTN_THROW] = {
 136                 .error  = -EAGAIN,
 137                 .scope  = RT_SCOPE_UNIVERSE,
 138         },
 139         [RTN_NAT] = {
 140                 .error  = -EINVAL,
 141                 .scope  = RT_SCOPE_NOWHERE,
 142         },
 143         [RTN_XRESOLVE] = {
 144                 .error  = -EINVAL,
 145                 .scope  = RT_SCOPE_NOWHERE,
 146         },
 147 };
 148
 149 static void rt_fibinfo_free(struct rtable __rcu **rtp)
 150 {
 151         struct rtable *rt = rcu_dereference_protected(*rtp, 1);
 152
 153         if (!rt)
 154                 return;
 155
 156         /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
 157          * because we waited an RCU grace period before calling
 158          * free_fib_info_rcu()
 159          */
 160
 161         dst_dev_put(&rt->dst);
 162         dst_release_immediate(&rt->dst);
 163 }
 164
 165 static void free_nh_exceptions(struct fib_nh_common *nhc)
 166 {
 167         struct fnhe_hash_bucket *hash;
 168         int i;
 169
 170         hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
 171         if (!hash)
 172                 return;
 173         for (i = 0; i < FNHE_HASH_SIZE; i++) {
 174                 struct fib_nh_exception *fnhe;
 175
 176                 fnhe = rcu_dereference_protected(hash[i].chain, 1);
 177                 while (fnhe) {
 178                         struct fib_nh_exception *next;
 179
 180                         next = rcu_dereference_protected(fnhe->fnhe_next, 1);
 181
 182                         rt_fibinfo_free(&fnhe->fnhe_rth_input);
 183                         rt_fibinfo_free(&fnhe->fnhe_rth_output);
 184
 185                         kfree(fnhe);
 186
 187                         fnhe = next;
 188                 }
 189         }
 190         kfree(hash);
 191 }
 192
 193 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 194 {
 195         int cpu;
 196
 197         if (!rtp)
 198                 return;
 199
 200         for_each_possible_cpu(cpu) {
 201                 struct rtable *rt;
 202
 203                 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
 204                 if (rt) {
 205                         dst_dev_put(&rt->dst);
 206                         dst_release_immediate(&rt->dst);
 207                 }
 208         }
 209         free_percpu(rtp);
 210 }
 211
 212 void fib_nh_common_release(struct fib_nh_common *nhc)
 213 {
 214         dev_put_track(nhc->nhc_dev, &nhc->nhc_dev_tracker);
 215         lwtstate_put(nhc->nhc_lwtstate);
 216         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 217         rt_fibinfo_free(&nhc->nhc_rth_input);
 218         free_nh_exceptions(nhc);
 219 }
 220 EXPORT_SYMBOL_GPL(fib_nh_common_release);
 221
 222 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 223 {
 224 #ifdef CONFIG_IP_ROUTE_CLASSID
 225         if (fib_nh->nh_tclassid)
 226                 atomic_dec(&net->ipv4.fib_num_tclassid_users);
 227 #endif
 228         fib_nh_common_release(&fib_nh->nh_common);
 229 }
 230
 231 /* Release a nexthop info record */
 232 static void free_fib_info_rcu(struct rcu_head *head)
 233 {
 234         struct fib_info *fi = container_of(head, struct fib_info, rcu);
 235
 236         if (fi->nh) {
 237                 nexthop_put(fi->nh);
 238         } else {
 239                 change_nexthops(fi) {
 240                         fib_nh_release(fi->fib_net, nexthop_nh);
 241                 } endfor_nexthops(fi);
 242         }
 243
 244         ip_fib_metrics_put(fi->fib_metrics);
 245
 246         kfree(fi);
 247 }
 248
 249 void free_fib_info(struct fib_info *fi)
 250 {
 251         if (fi->fib_dead == 0) {
 252                 pr_warn("Freeing alive fib_info %p\n", fi);
 253                 return;
 254         }
 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 && refcount_dec_and_test(&fi->fib_treeref)) {
 264                 hlist_del(&fi->fib_hash);
 265
 266                 /* Paired with READ_ONCE() in fib_create_info(). */
 267                 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
 268
 269                 if (fi->fib_prefsrc)
 270                         hlist_del(&fi->fib_lhash);
 271                 if (fi->nh) {
 272                         list_del(&fi->nh_list);
 273                 } else {
 274                         change_nexthops(fi) {
 275                                 if (!nexthop_nh->fib_nh_dev)
 276                                         continue;
 277                                 hlist_del(&nexthop_nh->nh_hash);
 278                         } endfor_nexthops(fi)
 279                 }
 280                 fi->fib_dead = 1;
 281                 fib_info_put(fi);
 282         }
 283         spin_unlock_bh(&fib_info_lock);
 284 }
 285
 286 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
 287 {
 288         const struct fib_nh *onh;
 289
 290         if (fi->nh || ofi->nh)
 291                 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
 292
 293         if (ofi->fib_nhs == 0)
 294                 return 0;
 295
 296         for_nexthops(fi) {
 297                 onh = fib_info_nh(ofi, nhsel);
 298
 299                 if (nh->fib_nh_oif != onh->fib_nh_oif ||
 300                     nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
 301                     nh->fib_nh_scope != onh->fib_nh_scope ||
 302 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 303                     nh->fib_nh_weight != onh->fib_nh_weight ||
 304 #endif
 305 #ifdef CONFIG_IP_ROUTE_CLASSID
 306                     nh->nh_tclassid != onh->nh_tclassid ||
 307 #endif
 308                     lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
 309                     ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
 310                         return -1;
 311
 312                 if (nh->fib_nh_gw_family == AF_INET &&
 313                     nh->fib_nh_gw4 != onh->fib_nh_gw4)
 314                         return -1;
 315
 316                 if (nh->fib_nh_gw_family == AF_INET6 &&
 317                     ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
 318                         return -1;
 319         } endfor_nexthops(fi);
 320         return 0;
 321 }
 322
 323 static inline unsigned int fib_devindex_hashfn(unsigned int val)
 324 {
 325         return hash_32(val, DEVINDEX_HASHBITS);
 326 }
 327
 328 static struct hlist_head *
 329 fib_info_devhash_bucket(const struct net_device *dev)
 330 {
 331         u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
 332
 333         return &fib_info_devhash[fib_devindex_hashfn(val)];
 334 }
 335
 336 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
 337                                       u32 prefsrc, u32 priority)
 338 {
 339         unsigned int val = init_val;
 340
 341         val ^= (protocol << 8) | scope;
 342         val ^= prefsrc;
 343         val ^= priority;
 344
 345         return val;
 346 }
 347
 348 static unsigned int fib_info_hashfn_result(unsigned int val)
 349 {
 350         unsigned int mask = (fib_info_hash_size - 1);
 351
 352         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 353 }
 354
 355 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 356 {
 357         unsigned int val;
 358
 359         val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
 360                                 fi->fib_scope, (__force u32)fi->fib_prefsrc,
 361                                 fi->fib_priority);
 362
 363         if (fi->nh) {
 364                 val ^= fib_devindex_hashfn(fi->nh->id);
 365         } else {
 366                 for_nexthops(fi) {
 367                         val ^= fib_devindex_hashfn(nh->fib_nh_oif);
 368                 } endfor_nexthops(fi)
 369         }
 370
 371         return fib_info_hashfn_result(val);
 372 }
 373
 374 /* no metrics, only nexthop id */
 375 static struct fib_info *fib_find_info_nh(struct net *net,
 376                                          const struct fib_config *cfg)
 377 {
 378         struct hlist_head *head;
 379         struct fib_info *fi;
 380         unsigned int hash;
 381
 382         hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
 383                                  cfg->fc_protocol, cfg->fc_scope,
 384                                  (__force u32)cfg->fc_prefsrc,
 385                                  cfg->fc_priority);
 386         hash = fib_info_hashfn_result(hash);
 387         head = &fib_info_hash[hash];
 388
 389         hlist_for_each_entry(fi, head, fib_hash) {
 390                 if (!net_eq(fi->fib_net, net))
 391                         continue;
 392                 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
 393                         continue;
 394                 if (cfg->fc_protocol == fi->fib_protocol &&
 395                     cfg->fc_scope == fi->fib_scope &&
 396                     cfg->fc_prefsrc == fi->fib_prefsrc &&
 397                     cfg->fc_priority == fi->fib_priority &&
 398                     cfg->fc_type == fi->fib_type &&
 399                     cfg->fc_table == fi->fib_tb_id &&
 400                     !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
 401                         return fi;
 402         }
 403
 404         return NULL;
 405 }
 406
 407 static struct fib_info *fib_find_info(struct fib_info *nfi)
 408 {
 409         struct hlist_head *head;
 410         struct fib_info *fi;
 411         unsigned int hash;
 412
 413         hash = fib_info_hashfn(nfi);
 414         head = &fib_info_hash[hash];
 415
 416         hlist_for_each_entry(fi, head, fib_hash) {
 417                 if (!net_eq(fi->fib_net, nfi->fib_net))
 418                         continue;
 419                 if (fi->fib_nhs != nfi->fib_nhs)
 420                         continue;
 421                 if (nfi->fib_protocol == fi->fib_protocol &&
 422                     nfi->fib_scope == fi->fib_scope &&
 423                     nfi->fib_prefsrc == fi->fib_prefsrc &&
 424                     nfi->fib_priority == fi->fib_priority &&
 425                     nfi->fib_type == fi->fib_type &&
 426                     memcmp(nfi->fib_metrics, fi->fib_metrics,
 427                            sizeof(u32) * RTAX_MAX) == 0 &&
 428                     !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 429                     nh_comp(fi, nfi) == 0)
 430                         return fi;
 431         }
 432
 433         return NULL;
 434 }
 435
 436 /* Check, that the gateway is already configured.
 437  * Used only by redirect accept routine.
 438  */
 439 int ip_fib_check_default(__be32 gw, struct net_device *dev)
 440 {
 441         struct hlist_head *head;
 442         struct fib_nh *nh;
 443
 444         spin_lock(&fib_info_lock);
 445
 446         head = fib_info_devhash_bucket(dev);
 447
 448         hlist_for_each_entry(nh, head, nh_hash) {
 449                 if (nh->fib_nh_dev == dev &&
 450                     nh->fib_nh_gw4 == gw &&
 451                     !(nh->fib_nh_flags & RTNH_F_DEAD)) {
 452                         spin_unlock(&fib_info_lock);
 453                         return 0;
 454                 }
 455         }
 456
 457         spin_unlock(&fib_info_lock);
 458
 459         return -1;
 460 }
 461
 462 size_t fib_nlmsg_size(struct fib_info *fi)
 463 {
 464         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 465                          + nla_total_size(4) /* RTA_TABLE */
 466                          + nla_total_size(4) /* RTA_DST */
 467                          + nla_total_size(4) /* RTA_PRIORITY */
 468                          + nla_total_size(4) /* RTA_PREFSRC */
 469                          + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 470         unsigned int nhs = fib_info_num_path(fi);
 471
 472         /* space for nested metrics */
 473         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 474
 475         if (fi->nh)
 476                 payload += nla_total_size(4); /* RTA_NH_ID */
 477
 478         if (nhs) {
 479                 size_t nh_encapsize = 0;
 480                 /* Also handles the special case nhs == 1 */
 481
 482                 /* each nexthop is packed in an attribute */
 483                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 484                 unsigned int i;
 485
 486                 /* may contain flow and gateway attribute */
 487                 nhsize += 2 * nla_total_size(4);
 488
 489                 /* grab encap info */
 490                 for (i = 0; i < fib_info_num_path(fi); i++) {
 491                         struct fib_nh_common *nhc = fib_info_nhc(fi, i);
 492
 493                         if (nhc->nhc_lwtstate) {
 494                                 /* RTA_ENCAP_TYPE */
 495                                 nh_encapsize += lwtunnel_get_encap_size(
 496                                                 nhc->nhc_lwtstate);
 497                                 /* RTA_ENCAP */
 498                                 nh_encapsize +=  nla_total_size(2);
 499                         }
 500                 }
 501
 502                 /* all nexthops are packed in a nested attribute */
 503                 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
 504
 505         }
 506
 507         return payload;
 508 }
 509
 510 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 511                int dst_len, u32 tb_id, const struct nl_info *info,
 512                unsigned int nlm_flags)
 513 {
 514         struct fib_rt_info fri;
 515         struct sk_buff *skb;
 516         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 517         int err = -ENOBUFS;
 518
 519         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 520         if (!skb)
 521                 goto errout;
 522
 523         fri.fi = fa->fa_info;
 524         fri.tb_id = tb_id;
 525         fri.dst = key;
 526         fri.dst_len = dst_len;
 527         fri.tos = inet_dscp_to_dsfield(fa->fa_dscp);
 528         fri.type = fa->fa_type;
 529         fri.offload = READ_ONCE(fa->offload);
 530         fri.trap = READ_ONCE(fa->trap);
 531         fri.offload_failed = READ_ONCE(fa->offload_failed);
 532         err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
 533         if (err < 0) {
 534                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 535                 WARN_ON(err == -EMSGSIZE);
 536                 kfree_skb(skb);
 537                 goto errout;
 538         }
 539         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 540                     info->nlh, GFP_KERNEL);
 541         return;
 542 errout:
 543         if (err < 0)
 544                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 545 }
 546
 547 static int fib_detect_death(struct fib_info *fi, int order,
 548                             struct fib_info **last_resort, int *last_idx,
 549                             int dflt)
 550 {
 551         const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 552         struct neighbour *n;
 553         int state = NUD_NONE;
 554
 555         if (likely(nhc->nhc_gw_family == AF_INET))
 556                 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 557         else if (nhc->nhc_gw_family == AF_INET6)
 558                 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 559                                  nhc->nhc_dev);
 560         else
 561                 n = NULL;
 562
 563         if (n) {
 564                 state = n->nud_state;
 565                 neigh_release(n);
 566         } else {
 567                 return 0;
 568         }
 569         if (state == NUD_REACHABLE)
 570                 return 0;
 571         if ((state & NUD_VALID) && order != dflt)
 572                 return 0;
 573         if ((state & NUD_VALID) ||
 574             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 575                 *last_resort = fi;
 576                 *last_idx = order;
 577         }
 578         return 1;
 579 }
 580
 581 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 582                        struct nlattr *encap, u16 encap_type,
 583                        void *cfg, gfp_t gfp_flags,
 584                        struct netlink_ext_ack *extack)
 585 {
 586         int err;
 587
 588         nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 589                                                     gfp_flags);
 590         if (!nhc->nhc_pcpu_rth_output)
 591                 return -ENOMEM;
 592
 593         if (encap) {
 594                 struct lwtunnel_state *lwtstate;
 595
 596                 if (encap_type == LWTUNNEL_ENCAP_NONE) {
 597                         NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 598                         err = -EINVAL;
 599                         goto lwt_failure;
 600                 }
 601                 err = lwtunnel_build_state(net, encap_type, encap,
 602                                            nhc->nhc_family, cfg, &lwtstate,
 603                                            extack);
 604                 if (err)
 605                         goto lwt_failure;
 606
 607                 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 608         }
 609
 610         return 0;
 611
 612 lwt_failure:
 613         rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 614         nhc->nhc_pcpu_rth_output = NULL;
 615         return err;
 616 }
 617 EXPORT_SYMBOL_GPL(fib_nh_common_init);
 618
 619 int fib_nh_init(struct net *net, struct fib_nh *nh,
 620                 struct fib_config *cfg, int nh_weight,
 621                 struct netlink_ext_ack *extack)
 622 {
 623         int err;
 624
 625         nh->fib_nh_family = AF_INET;
 626
 627         err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
 628                                  cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 629         if (err)
 630                 return err;
 631
 632         nh->fib_nh_oif = cfg->fc_oif;
 633         nh->fib_nh_gw_family = cfg->fc_gw_family;
 634         if (cfg->fc_gw_family == AF_INET)
 635                 nh->fib_nh_gw4 = cfg->fc_gw4;
 636         else if (cfg->fc_gw_family == AF_INET6)
 637                 nh->fib_nh_gw6 = cfg->fc_gw6;
 638
 639         nh->fib_nh_flags = cfg->fc_flags;
 640
 641 #ifdef CONFIG_IP_ROUTE_CLASSID
 642         nh->nh_tclassid = cfg->fc_flow;
 643         if (nh->nh_tclassid)
 644                 atomic_inc(&net->ipv4.fib_num_tclassid_users);
 645 #endif
 646 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 647         nh->fib_nh_weight = nh_weight;
 648 #endif
 649         return 0;
 650 }
 651
 652 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 653
 654 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 655                               struct netlink_ext_ack *extack)
 656 {
 657         int nhs = 0;
 658
 659         while (rtnh_ok(rtnh, remaining)) {
 660                 nhs++;
 661                 rtnh = rtnh_next(rtnh, &remaining);
 662         }
 663
 664         /* leftover implies invalid nexthop configuration, discard it */
 665         if (remaining > 0) {
 666                 NL_SET_ERR_MSG(extack,
 667                                "Invalid nexthop configuration - extra data after nexthops");
 668                 nhs = 0;
 669         }
 670
 671         return nhs;
 672 }
 673
 674 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
 675                             struct netlink_ext_ack *extack)
 676 {
 677         if (nla_len(nla) < sizeof(*gw)) {
 678                 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
 679                 return -EINVAL;
 680         }
 681
 682         *gw = nla_get_in_addr(nla);
 683
 684         return 0;
 685 }
 686
 687 /* only called when fib_nh is integrated into fib_info */
 688 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 689                        int remaining, struct fib_config *cfg,
 690                        struct netlink_ext_ack *extack)
 691 {
 692         struct net *net = fi->fib_net;
 693         struct fib_config fib_cfg;
 694         struct fib_nh *nh;
 695         int ret;
 696
 697         change_nexthops(fi) {
 698                 int attrlen;
 699
 700                 memset(&fib_cfg, 0, sizeof(fib_cfg));
 701
 702                 if (!rtnh_ok(rtnh, remaining)) {
 703                         NL_SET_ERR_MSG(extack,
 704                                        "Invalid nexthop configuration - extra data after nexthop");
 705                         return -EINVAL;
 706                 }
 707
 708                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 709                         NL_SET_ERR_MSG(extack,
 710                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 711                         return -EINVAL;
 712                 }
 713
 714                 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 715                 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 716
 717                 attrlen = rtnh_attrlen(rtnh);
 718                 if (attrlen > 0) {
 719                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 720
 721                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 722                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 723                         if (nla && nlav) {
 724                                 NL_SET_ERR_MSG(extack,
 725                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 726                                 return -EINVAL;
 727                         }
 728                         if (nla) {
 729                                 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
 730                                                        extack);
 731                                 if (ret)
 732                                         goto errout;
 733
 734                                 if (fib_cfg.fc_gw4)
 735                                         fib_cfg.fc_gw_family = AF_INET;
 736                         } else if (nlav) {
 737                                 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 738                                 if (ret)
 739                                         goto errout;
 740                         }
 741
 742                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 743                         if (nla) {
 744                                 if (nla_len(nla) < sizeof(u32)) {
 745                                         NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
 746                                         return -EINVAL;
 747                                 }
 748                                 fib_cfg.fc_flow = nla_get_u32(nla);
 749                         }
 750
 751                         fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 752                         /* RTA_ENCAP_TYPE length checked in
 753                          * lwtunnel_valid_encap_type_attr
 754                          */
 755                         nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 756                         if (nla)
 757                                 fib_cfg.fc_encap_type = nla_get_u16(nla);
 758                 }
 759
 760                 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 761                                   rtnh->rtnh_hops + 1, extack);
 762                 if (ret)
 763                         goto errout;
 764
 765                 rtnh = rtnh_next(rtnh, &remaining);
 766         } endfor_nexthops(fi);
 767
 768         ret = -EINVAL;
 769         nh = fib_info_nh(fi, 0);
 770         if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 771                 NL_SET_ERR_MSG(extack,
 772                                "Nexthop device index does not match RTA_OIF");
 773                 goto errout;
 774         }
 775         if (cfg->fc_gw_family) {
 776                 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 777                     (cfg->fc_gw_family == AF_INET &&
 778                      nh->fib_nh_gw4 != cfg->fc_gw4) ||
 779                     (cfg->fc_gw_family == AF_INET6 &&
 780                      ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 781                         NL_SET_ERR_MSG(extack,
 782                                        "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 783                         goto errout;
 784                 }
 785         }
 786 #ifdef CONFIG_IP_ROUTE_CLASSID
 787         if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 788                 NL_SET_ERR_MSG(extack,
 789                                "Nexthop class id does not match RTA_FLOW");
 790                 goto errout;
 791         }
 792 #endif
 793         ret = 0;
 794 errout:
 795         return ret;
 796 }
 797
 798 /* only called when fib_nh is integrated into fib_info */
 799 static void fib_rebalance(struct fib_info *fi)
 800 {
 801         int total;
 802         int w;
 803
 804         if (fib_info_num_path(fi) < 2)
 805                 return;
 806
 807         total = 0;
 808         for_nexthops(fi) {
 809                 if (nh->fib_nh_flags & RTNH_F_DEAD)
 810                         continue;
 811
 812                 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 813                     nh->fib_nh_flags & RTNH_F_LINKDOWN)
 814                         continue;
 815
 816                 total += nh->fib_nh_weight;
 817         } endfor_nexthops(fi);
 818
 819         w = 0;
 820         change_nexthops(fi) {
 821                 int upper_bound;
 822
 823                 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 824                         upper_bound = -1;
 825                 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 826                            nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 827                         upper_bound = -1;
 828                 } else {
 829                         w += nexthop_nh->fib_nh_weight;
 830                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 831                                                             total) - 1;
 832                 }
 833
 834                 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 835         } endfor_nexthops(fi);
 836 }
 837 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 838
 839 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 840                        int remaining, struct fib_config *cfg,
 841                        struct netlink_ext_ack *extack)
 842 {
 843         NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 844
 845         return -EINVAL;
 846 }
 847
 848 #define fib_rebalance(fi) do { } while (0)
 849
 850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 851
 852 static int fib_encap_match(struct net *net, u16 encap_type,
 853                            struct nlattr *encap,
 854                            const struct fib_nh *nh,
 855                            const struct fib_config *cfg,
 856                            struct netlink_ext_ack *extack)
 857 {
 858         struct lwtunnel_state *lwtstate;
 859         int ret, result = 0;
 860
 861         if (encap_type == LWTUNNEL_ENCAP_NONE)
 862                 return 0;
 863
 864         ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
 865                                    cfg, &lwtstate, extack);
 866         if (!ret) {
 867                 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 868                 lwtstate_free(lwtstate);
 869         }
 870
 871         return result;
 872 }
 873
 874 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
 875                  struct netlink_ext_ack *extack)
 876 {
 877 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 878         struct rtnexthop *rtnh;
 879         int remaining;
 880 #endif
 881
 882         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 883                 return 1;
 884
 885         if (cfg->fc_nh_id) {
 886                 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 887                         return 0;
 888                 return 1;
 889         }
 890
 891         if (cfg->fc_oif || cfg->fc_gw_family) {
 892                 struct fib_nh *nh = fib_info_nh(fi, 0);
 893
 894                 if (cfg->fc_encap) {
 895                         if (fib_encap_match(net, cfg->fc_encap_type,
 896                                             cfg->fc_encap, nh, cfg, extack))
 897                                 return 1;
 898                 }
 899 #ifdef CONFIG_IP_ROUTE_CLASSID
 900                 if (cfg->fc_flow &&
 901                     cfg->fc_flow != nh->nh_tclassid)
 902                         return 1;
 903 #endif
 904                 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 905                     (cfg->fc_gw_family &&
 906                      cfg->fc_gw_family != nh->fib_nh_gw_family))
 907                         return 1;
 908
 909                 if (cfg->fc_gw_family == AF_INET &&
 910                     cfg->fc_gw4 != nh->fib_nh_gw4)
 911                         return 1;
 912
 913                 if (cfg->fc_gw_family == AF_INET6 &&
 914                     ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 915                         return 1;
 916
 917                 return 0;
 918         }
 919
 920 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 921         if (!cfg->fc_mp)
 922                 return 0;
 923
 924         rtnh = cfg->fc_mp;
 925         remaining = cfg->fc_mp_len;
 926
 927         for_nexthops(fi) {
 928                 int attrlen;
 929
 930                 if (!rtnh_ok(rtnh, remaining))
 931                         return -EINVAL;
 932
 933                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 934                         return 1;
 935
 936                 attrlen = rtnh_attrlen(rtnh);
 937                 if (attrlen > 0) {
 938                         struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 939                         int err;
 940
 941                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 942                         nlav = nla_find(attrs, attrlen, RTA_VIA);
 943                         if (nla && nlav) {
 944                                 NL_SET_ERR_MSG(extack,
 945                                                "Nexthop configuration can not contain both GATEWAY and VIA");
 946                                 return -EINVAL;
 947                         }
 948
 949                         if (nla) {
 950                                 __be32 gw;
 951
 952                                 err = fib_gw_from_attr(&gw, nla, extack);
 953                                 if (err)
 954                                         return err;
 955
 956                                 if (nh->fib_nh_gw_family != AF_INET ||
 957                                     gw != nh->fib_nh_gw4)
 958                                         return 1;
 959                         } else if (nlav) {
 960                                 struct fib_config cfg2;
 961
 962                                 err = fib_gw_from_via(&cfg2, nlav, extack);
 963                                 if (err)
 964                                         return err;
 965
 966                                 switch (nh->fib_nh_gw_family) {
 967                                 case AF_INET:
 968                                         if (cfg2.fc_gw_family != AF_INET ||
 969                                             cfg2.fc_gw4 != nh->fib_nh_gw4)
 970                                                 return 1;
 971                                         break;
 972                                 case AF_INET6:
 973                                         if (cfg2.fc_gw_family != AF_INET6 ||
 974                                             ipv6_addr_cmp(&cfg2.fc_gw6,
 975                                                           &nh->fib_nh_gw6))
 976                                                 return 1;
 977                                         break;
 978                                 }
 979                         }
 980
 981 #ifdef CONFIG_IP_ROUTE_CLASSID
 982                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 983                         if (nla) {
 984                                 if (nla_len(nla) < sizeof(u32)) {
 985                                         NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
 986                                         return -EINVAL;
 987                                 }
 988                                 if (nla_get_u32(nla) != nh->nh_tclassid)
 989                                         return 1;
 990                         }
 991 #endif
 992                 }
 993
 994                 rtnh = rtnh_next(rtnh, &remaining);
 995         } endfor_nexthops(fi);
 996 #endif
 997         return 0;
 998 }
 999
1000 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1001 {
1002         struct nlattr *nla;
1003         int remaining;
1004
1005         if (!cfg->fc_mx)
1006                 return true;
1007
1008         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1009                 int type = nla_type(nla);
1010                 u32 fi_val, val;
1011
1012                 if (!type)
1013                         continue;
1014                 if (type > RTAX_MAX)
1015                         return false;
1016
1017                 if (type == RTAX_CC_ALGO) {
1018                         char tmp[TCP_CA_NAME_MAX];
1019                         bool ecn_ca = false;
1020
1021                         nla_strscpy(tmp, nla, sizeof(tmp));
1022                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1023                 } else {
1024                         if (nla_len(nla) != sizeof(u32))
1025                                 return false;
1026                         val = nla_get_u32(nla);
1027                 }
1028
1029                 fi_val = fi->fib_metrics->metrics[type - 1];
1030                 if (type == RTAX_FEATURES)
1031                         fi_val &= ~DST_FEATURE_ECN_CA;
1032
1033                 if (fi_val != val)
1034                         return false;
1035         }
1036
1037         return true;
1038 }
1039
1040 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1041                               u32 table, struct netlink_ext_ack *extack)
1042 {
1043         struct fib6_config cfg = {
1044                 .fc_table = table,
1045                 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1046                 .fc_ifindex = nh->fib_nh_oif,
1047                 .fc_gateway = nh->fib_nh_gw6,
1048         };
1049         struct fib6_nh fib6_nh = {};
1050         int err;
1051
1052         err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1053         if (!err) {
1054                 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1055                 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL);
1056                 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1057                 nh->fib_nh_scope = RT_SCOPE_LINK;
1058
1059                 ipv6_stub->fib6_nh_release(&fib6_nh);
1060         }
1061
1062         return err;
1063 }
1064
1065 /*
1066  * Picture
1067  * -------
1068  *
1069  * Semantics of nexthop is very messy by historical reasons.
1070  * We have to take into account, that:
1071  * a) gateway can be actually local interface address,
1072  *    so that gatewayed route is direct.
1073  * b) gateway must be on-link address, possibly
1074  *    described not by an ifaddr, but also by a direct route.
1075  * c) If both gateway and interface are specified, they should not
1076  *    contradict.
1077  * d) If we use tunnel routes, gateway could be not on-link.
1078  *
1079  * Attempt to reconcile all of these (alas, self-contradictory) conditions
1080  * results in pretty ugly and hairy code with obscure logic.
1081  *
1082  * I chose to generalized it instead, so that the size
1083  * of code does not increase practically, but it becomes
1084  * much more general.
1085  * Every prefix is assigned a "scope" value: "host" is local address,
1086  * "link" is direct route,
1087  * [ ... "site" ... "interior" ... ]
1088  * and "universe" is true gateway route with global meaning.
1089  *
1090  * Every prefix refers to a set of "nexthop"s (gw, oif),
1091  * where gw must have narrower scope. This recursion stops
1092  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1093  * which means that gw is forced to be on link.
1094  *
1095  * Code is still hairy, but now it is apparently logically
1096  * consistent and very flexible. F.e. as by-product it allows
1097  * to co-exists in peace independent exterior and interior
1098  * routing processes.
1099  *
1100  * Normally it looks as following.
1101  *
1102  * {universe prefix}  -> (gw, oif) [scope link]
1103  *                |
1104  *                |-> {link prefix} -> (gw, oif) [scope local]
1105  *                                      |
1106  *                                      |-> {local prefix} (terminal node)
1107  */
1108 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1109                               u8 scope, struct netlink_ext_ack *extack)
1110 {
1111         struct net_device *dev;
1112         struct fib_result res;
1113         int err = 0;
1114
1115         if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1116                 unsigned int addr_type;
1117
1118                 if (scope >= RT_SCOPE_LINK) {
1119                         NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1120                         return -EINVAL;
1121                 }
1122                 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1123                 if (!dev) {
1124                         NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1125                         return -ENODEV;
1126                 }
1127                 if (!(dev->flags & IFF_UP)) {
1128                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1129                         return -ENETDOWN;
1130                 }
1131                 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1132                 if (addr_type != RTN_UNICAST) {
1133                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1134                         return -EINVAL;
1135                 }
1136                 if (!netif_carrier_ok(dev))
1137                         nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1138                 nh->fib_nh_dev = dev;
1139                 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1140                 nh->fib_nh_scope = RT_SCOPE_LINK;
1141                 return 0;
1142         }
1143         rcu_read_lock();
1144         {
1145                 struct fib_table *tbl = NULL;
1146                 struct flowi4 fl4 = {
1147                         .daddr = nh->fib_nh_gw4,
1148                         .flowi4_scope = scope + 1,
1149                         .flowi4_oif = nh->fib_nh_oif,
1150                         .flowi4_iif = LOOPBACK_IFINDEX,
1151                 };
1152
1153                 /* It is not necessary, but requires a bit of thinking */
1154                 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1155                         fl4.flowi4_scope = RT_SCOPE_LINK;
1156
1157                 if (table && table != RT_TABLE_MAIN)
1158                         tbl = fib_get_table(net, table);
1159
1160                 if (tbl)
1161                         err = fib_table_lookup(tbl, &fl4, &res,
1162                                                FIB_LOOKUP_IGNORE_LINKSTATE |
1163                                                FIB_LOOKUP_NOREF);
1164
1165                 /* on error or if no table given do full lookup. This
1166                  * is needed for example when nexthops are in the local
1167                  * table rather than the given table
1168                  */
1169                 if (!tbl || err) {
1170                         err = fib_lookup(net, &fl4, &res,
1171                                          FIB_LOOKUP_IGNORE_LINKSTATE);
1172                 }
1173
1174                 if (err) {
1175                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1176                         goto out;
1177                 }
1178         }
1179
1180         err = -EINVAL;
1181         if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1182                 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1183                 goto out;
1184         }
1185         nh->fib_nh_scope = res.scope;
1186         nh->fib_nh_oif = FIB_RES_OIF(res);
1187         nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1188         if (!dev) {
1189                 NL_SET_ERR_MSG(extack,
1190                                "No egress device for nexthop gateway");
1191                 goto out;
1192         }
1193         dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1194         if (!netif_carrier_ok(dev))
1195                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1196         err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1197 out:
1198         rcu_read_unlock();
1199         return err;
1200 }
1201
1202 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1203                               struct netlink_ext_ack *extack)
1204 {
1205         struct in_device *in_dev;
1206         int err;
1207
1208         if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1209                 NL_SET_ERR_MSG(extack,
1210                                "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1211                 return -EINVAL;
1212         }
1213
1214         rcu_read_lock();
1215
1216         err = -ENODEV;
1217         in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1218         if (!in_dev)
1219                 goto out;
1220         err = -ENETDOWN;
1221         if (!(in_dev->dev->flags & IFF_UP)) {
1222                 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1223                 goto out;
1224         }
1225
1226         nh->fib_nh_dev = in_dev->dev;
1227         dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1228         nh->fib_nh_scope = RT_SCOPE_HOST;
1229         if (!netif_carrier_ok(nh->fib_nh_dev))
1230                 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1231         err = 0;
1232 out:
1233         rcu_read_unlock();
1234         return err;
1235 }
1236
1237 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1238                  struct netlink_ext_ack *extack)
1239 {
1240         int err;
1241
1242         if (nh->fib_nh_gw_family == AF_INET)
1243                 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1244         else if (nh->fib_nh_gw_family == AF_INET6)
1245                 err = fib_check_nh_v6_gw(net, nh, table, extack);
1246         else
1247                 err = fib_check_nh_nongw(net, nh, extack);
1248
1249         return err;
1250 }
1251
1252 static struct hlist_head *
1253 fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1254 {
1255         u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1256                            fib_info_hash_bits);
1257
1258         return &fib_info_laddrhash[slot];
1259 }
1260
1261 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1262                                struct hlist_head *new_laddrhash,
1263                                unsigned int new_size)
1264 {
1265         struct hlist_head *old_info_hash, *old_laddrhash;
1266         unsigned int old_size = fib_info_hash_size;
1267         unsigned int i;
1268
1269         spin_lock_bh(&fib_info_lock);
1270         old_info_hash = fib_info_hash;
1271         old_laddrhash = fib_info_laddrhash;
1272         fib_info_hash_size = new_size;
1273         fib_info_hash_bits = ilog2(new_size);
1274
1275         for (i = 0; i < old_size; i++) {
1276                 struct hlist_head *head = &fib_info_hash[i];
1277                 struct hlist_node *n;
1278                 struct fib_info *fi;
1279
1280                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1281                         struct hlist_head *dest;
1282                         unsigned int new_hash;
1283
1284                         new_hash = fib_info_hashfn(fi);
1285                         dest = &new_info_hash[new_hash];
1286                         hlist_add_head(&fi->fib_hash, dest);
1287                 }
1288         }
1289         fib_info_hash = new_info_hash;
1290
1291         fib_info_laddrhash = new_laddrhash;
1292         for (i = 0; i < old_size; i++) {
1293                 struct hlist_head *lhead = &old_laddrhash[i];
1294                 struct hlist_node *n;
1295                 struct fib_info *fi;
1296
1297                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1298                         struct hlist_head *ldest;
1299
1300                         ldest = fib_info_laddrhash_bucket(fi->fib_net,
1301                                                           fi->fib_prefsrc);
1302                         hlist_add_head(&fi->fib_lhash, ldest);
1303                 }
1304         }
1305
1306         spin_unlock_bh(&fib_info_lock);
1307
1308         kvfree(old_info_hash);
1309         kvfree(old_laddrhash);
1310 }
1311
1312 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1313                                  unsigned char scope)
1314 {
1315         struct fib_nh *nh;
1316
1317         if (nhc->nhc_family != AF_INET)
1318                 return inet_select_addr(nhc->nhc_dev, 0, scope);
1319
1320         nh = container_of(nhc, struct fib_nh, nh_common);
1321         nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1322         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1323
1324         return nh->nh_saddr;
1325 }
1326
1327 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1328 {
1329         struct fib_nh_common *nhc = res->nhc;
1330
1331         if (res->fi->fib_prefsrc)
1332                 return res->fi->fib_prefsrc;
1333
1334         if (nhc->nhc_family == AF_INET) {
1335                 struct fib_nh *nh;
1336
1337                 nh = container_of(nhc, struct fib_nh, nh_common);
1338                 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1339                         return nh->nh_saddr;
1340         }
1341
1342         return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1343 }
1344
1345 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1346 {
1347         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1348             fib_prefsrc != cfg->fc_dst) {
1349                 u32 tb_id = cfg->fc_table;
1350                 int rc;
1351
1352                 if (tb_id == RT_TABLE_MAIN)
1353                         tb_id = RT_TABLE_LOCAL;
1354
1355                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1356                                           fib_prefsrc, tb_id);
1357
1358                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1359                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1360                                                   fib_prefsrc, RT_TABLE_LOCAL);
1361                 }
1362
1363                 if (rc != RTN_LOCAL)
1364                         return false;
1365         }
1366         return true;
1367 }
1368
1369 struct fib_info *fib_create_info(struct fib_config *cfg,
1370                                  struct netlink_ext_ack *extack)
1371 {
1372         int err;
1373         struct fib_info *fi = NULL;
1374         struct nexthop *nh = NULL;
1375         struct fib_info *ofi;
1376         int nhs = 1;
1377         struct net *net = cfg->fc_nlinfo.nl_net;
1378
1379         if (cfg->fc_type > RTN_MAX)
1380                 goto err_inval;
1381
1382         /* Fast check to catch the most weird cases */
1383         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1384                 NL_SET_ERR_MSG(extack, "Invalid scope");
1385                 goto err_inval;
1386         }
1387
1388         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1389                 NL_SET_ERR_MSG(extack,
1390                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1391                 goto err_inval;
1392         }
1393
1394         if (cfg->fc_nh_id) {
1395                 if (!cfg->fc_mx) {
1396                         fi = fib_find_info_nh(net, cfg);
1397                         if (fi) {
1398                                 refcount_inc(&fi->fib_treeref);
1399                                 return fi;
1400                         }
1401                 }
1402
1403                 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1404                 if (!nh) {
1405                         NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1406                         goto err_inval;
1407                 }
1408                 nhs = 0;
1409         }
1410
1411 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1412         if (cfg->fc_mp) {
1413                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1414                 if (nhs == 0)
1415                         goto err_inval;
1416         }
1417 #endif
1418
1419         err = -ENOBUFS;
1420
1421         /* Paired with WRITE_ONCE() in fib_release_info() */
1422         if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1423                 unsigned int new_size = fib_info_hash_size << 1;
1424                 struct hlist_head *new_info_hash;
1425                 struct hlist_head *new_laddrhash;
1426                 size_t bytes;
1427
1428                 if (!new_size)
1429                         new_size = 16;
1430                 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1431                 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1432                 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1433                 if (!new_info_hash || !new_laddrhash) {
1434                         kvfree(new_info_hash);
1435                         kvfree(new_laddrhash);
1436                 } else {
1437                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1438                 }
1439                 if (!fib_info_hash_size)
1440                         goto failure;
1441         }
1442
1443         fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1444         if (!fi)
1445                 goto failure;
1446         fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1447                                               cfg->fc_mx_len, extack);
1448         if (IS_ERR(fi->fib_metrics)) {
1449                 err = PTR_ERR(fi->fib_metrics);
1450                 kfree(fi);
1451                 return ERR_PTR(err);
1452         }
1453
1454         fi->fib_net = net;
1455         fi->fib_protocol = cfg->fc_protocol;
1456         fi->fib_scope = cfg->fc_scope;
1457         fi->fib_flags = cfg->fc_flags;
1458         fi->fib_priority = cfg->fc_priority;
1459         fi->fib_prefsrc = cfg->fc_prefsrc;
1460         fi->fib_type = cfg->fc_type;
1461         fi->fib_tb_id = cfg->fc_table;
1462
1463         fi->fib_nhs = nhs;
1464         if (nh) {
1465                 if (!nexthop_get(nh)) {
1466                         NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1467                         err = -EINVAL;
1468                 } else {
1469                         err = 0;
1470                         fi->nh = nh;
1471                 }
1472         } else {
1473                 change_nexthops(fi) {
1474                         nexthop_nh->nh_parent = fi;
1475                 } endfor_nexthops(fi)
1476
1477                 if (cfg->fc_mp)
1478                         err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1479                                           extack);
1480                 else
1481                         err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1482         }
1483
1484         if (err != 0)
1485                 goto failure;
1486
1487         if (fib_props[cfg->fc_type].error) {
1488                 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1489                         NL_SET_ERR_MSG(extack,
1490                                        "Gateway, device and multipath can not be specified for this route type");
1491                         goto err_inval;
1492                 }
1493                 goto link_it;
1494         } else {
1495                 switch (cfg->fc_type) {
1496                 case RTN_UNICAST:
1497                 case RTN_LOCAL:
1498                 case RTN_BROADCAST:
1499                 case RTN_ANYCAST:
1500                 case RTN_MULTICAST:
1501                         break;
1502                 default:
1503                         NL_SET_ERR_MSG(extack, "Invalid route type");
1504                         goto err_inval;
1505                 }
1506         }
1507
1508         if (cfg->fc_scope > RT_SCOPE_HOST) {
1509                 NL_SET_ERR_MSG(extack, "Invalid scope");
1510                 goto err_inval;
1511         }
1512
1513         if (fi->nh) {
1514                 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1515                 if (err)
1516                         goto failure;
1517         } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1518                 struct fib_nh *nh = fi->fib_nh;
1519
1520                 /* Local address is added. */
1521                 if (nhs != 1) {
1522                         NL_SET_ERR_MSG(extack,
1523                                        "Route with host scope can not have multiple nexthops");
1524                         goto err_inval;
1525                 }
1526                 if (nh->fib_nh_gw_family) {
1527                         NL_SET_ERR_MSG(extack,
1528                                        "Route with host scope can not have a gateway");
1529                         goto err_inval;
1530                 }
1531                 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1532                 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1533                 err = -ENODEV;
1534                 if (!nh->fib_nh_dev)
1535                         goto failure;
1536                 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1537                                      GFP_KERNEL);
1538         } else {
1539                 int linkdown = 0;
1540
1541                 change_nexthops(fi) {
1542                         err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1543                                            cfg->fc_table, cfg->fc_scope,
1544                                            extack);
1545                         if (err != 0)
1546                                 goto failure;
1547                         if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1548                                 linkdown++;
1549                 } endfor_nexthops(fi)
1550                 if (linkdown == fi->fib_nhs)
1551                         fi->fib_flags |= RTNH_F_LINKDOWN;
1552         }
1553
1554         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1555                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1556                 goto err_inval;
1557         }
1558
1559         if (!fi->nh) {
1560                 change_nexthops(fi) {
1561                         fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1562                                                   fi->fib_scope);
1563                         if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1564                                 fi->fib_nh_is_v6 = true;
1565                 } endfor_nexthops(fi)
1566
1567                 fib_rebalance(fi);
1568         }
1569
1570 link_it:
1571         ofi = fib_find_info(fi);
1572         if (ofi) {
1573                 fi->fib_dead = 1;
1574                 free_fib_info(fi);
1575                 refcount_inc(&ofi->fib_treeref);
1576                 return ofi;
1577         }
1578
1579         refcount_set(&fi->fib_treeref, 1);
1580         refcount_set(&fi->fib_clntref, 1);
1581         spin_lock_bh(&fib_info_lock);
1582         fib_info_cnt++;
1583         hlist_add_head(&fi->fib_hash,
1584                        &fib_info_hash[fib_info_hashfn(fi)]);
1585         if (fi->fib_prefsrc) {
1586                 struct hlist_head *head;
1587
1588                 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1589                 hlist_add_head(&fi->fib_lhash, head);
1590         }
1591         if (fi->nh) {
1592                 list_add(&fi->nh_list, &nh->fi_list);
1593         } else {
1594                 change_nexthops(fi) {
1595                         struct hlist_head *head;
1596
1597                         if (!nexthop_nh->fib_nh_dev)
1598                                 continue;
1599                         head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1600                         hlist_add_head(&nexthop_nh->nh_hash, head);
1601                 } endfor_nexthops(fi)
1602         }
1603         spin_unlock_bh(&fib_info_lock);
1604         return fi;
1605
1606 err_inval:
1607         err = -EINVAL;
1608
1609 failure:
1610         if (fi) {
1611                 fi->fib_dead = 1;
1612                 free_fib_info(fi);
1613         }
1614
1615         return ERR_PTR(err);
1616 }
1617
1618 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1619                      u8 rt_family, unsigned char *flags, bool skip_oif)
1620 {
1621         if (nhc->nhc_flags & RTNH_F_DEAD)
1622                 *flags |= RTNH_F_DEAD;
1623
1624         if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1625                 *flags |= RTNH_F_LINKDOWN;
1626
1627                 rcu_read_lock();
1628                 switch (nhc->nhc_family) {
1629                 case AF_INET:
1630                         if (ip_ignore_linkdown(nhc->nhc_dev))
1631                                 *flags |= RTNH_F_DEAD;
1632                         break;
1633                 case AF_INET6:
1634                         if (ip6_ignore_linkdown(nhc->nhc_dev))
1635                                 *flags |= RTNH_F_DEAD;
1636                         break;
1637                 }
1638                 rcu_read_unlock();
1639         }
1640
1641         switch (nhc->nhc_gw_family) {
1642         case AF_INET:
1643                 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1644                         goto nla_put_failure;
1645                 break;
1646         case AF_INET6:
1647                 /* if gateway family does not match nexthop family
1648                  * gateway is encoded as RTA_VIA
1649                  */
1650                 if (rt_family != nhc->nhc_gw_family) {
1651                         int alen = sizeof(struct in6_addr);
1652                         struct nlattr *nla;
1653                         struct rtvia *via;
1654
1655                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
1656                         if (!nla)
1657                                 goto nla_put_failure;
1658
1659                         via = nla_data(nla);
1660                         via->rtvia_family = AF_INET6;
1661                         memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1662                 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1663                                             &nhc->nhc_gw.ipv6) < 0) {
1664                         goto nla_put_failure;
1665                 }
1666                 break;
1667         }
1668
1669         *flags |= (nhc->nhc_flags &
1670                    (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1671
1672         if (!skip_oif && nhc->nhc_dev &&
1673             nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1674                 goto nla_put_failure;
1675
1676         if (nhc->nhc_lwtstate &&
1677             lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1678                                 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1679                 goto nla_put_failure;
1680
1681         return 0;
1682
1683 nla_put_failure:
1684         return -EMSGSIZE;
1685 }
1686 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1687
1688 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1689 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1690                     int nh_weight, u8 rt_family, u32 nh_tclassid)
1691 {
1692         const struct net_device *dev = nhc->nhc_dev;
1693         struct rtnexthop *rtnh;
1694         unsigned char flags = 0;
1695
1696         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1697         if (!rtnh)
1698                 goto nla_put_failure;
1699
1700         rtnh->rtnh_hops = nh_weight - 1;
1701         rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1702
1703         if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1704                 goto nla_put_failure;
1705
1706         rtnh->rtnh_flags = flags;
1707
1708         if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1709                 goto nla_put_failure;
1710
1711         /* length of rtnetlink header + attributes */
1712         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1713
1714         return 0;
1715
1716 nla_put_failure:
1717         return -EMSGSIZE;
1718 }
1719 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1720 #endif
1721
1722 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1723 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1724 {
1725         struct nlattr *mp;
1726
1727         mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1728         if (!mp)
1729                 goto nla_put_failure;
1730
1731         if (unlikely(fi->nh)) {
1732                 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1733                         goto nla_put_failure;
1734                 goto mp_end;
1735         }
1736
1737         for_nexthops(fi) {
1738                 u32 nh_tclassid = 0;
1739 #ifdef CONFIG_IP_ROUTE_CLASSID
1740                 nh_tclassid = nh->nh_tclassid;
1741 #endif
1742                 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1743                                     AF_INET, nh_tclassid) < 0)
1744                         goto nla_put_failure;
1745         } endfor_nexthops(fi);
1746
1747 mp_end:
1748         nla_nest_end(skb, mp);
1749
1750         return 0;
1751
1752 nla_put_failure:
1753         return -EMSGSIZE;
1754 }
1755 #else
1756 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1757 {
1758         return 0;
1759 }
1760 #endif
1761
1762 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1763                   const struct fib_rt_info *fri, unsigned int flags)
1764 {
1765         unsigned int nhs = fib_info_num_path(fri->fi);
1766         struct fib_info *fi = fri->fi;
1767         u32 tb_id = fri->tb_id;
1768         struct nlmsghdr *nlh;
1769         struct rtmsg *rtm;
1770
1771         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1772         if (!nlh)
1773                 return -EMSGSIZE;
1774
1775         rtm = nlmsg_data(nlh);
1776         rtm->rtm_family = AF_INET;
1777         rtm->rtm_dst_len = fri->dst_len;
1778         rtm->rtm_src_len = 0;
1779         rtm->rtm_tos = fri->tos;
1780         if (tb_id < 256)
1781                 rtm->rtm_table = tb_id;
1782         else
1783                 rtm->rtm_table = RT_TABLE_COMPAT;
1784         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1785                 goto nla_put_failure;
1786         rtm->rtm_type = fri->type;
1787         rtm->rtm_flags = fi->fib_flags;
1788         rtm->rtm_scope = fi->fib_scope;
1789         rtm->rtm_protocol = fi->fib_protocol;
1790
1791         if (rtm->rtm_dst_len &&
1792             nla_put_in_addr(skb, RTA_DST, fri->dst))
1793                 goto nla_put_failure;
1794         if (fi->fib_priority &&
1795             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1796                 goto nla_put_failure;
1797         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1798                 goto nla_put_failure;
1799
1800         if (fi->fib_prefsrc &&
1801             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1802                 goto nla_put_failure;
1803
1804         if (fi->nh) {
1805                 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1806                         goto nla_put_failure;
1807                 if (nexthop_is_blackhole(fi->nh))
1808                         rtm->rtm_type = RTN_BLACKHOLE;
1809                 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1810                         goto offload;
1811         }
1812
1813         if (nhs == 1) {
1814                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1815                 unsigned char flags = 0;
1816
1817                 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1818                         goto nla_put_failure;
1819
1820                 rtm->rtm_flags = flags;
1821 #ifdef CONFIG_IP_ROUTE_CLASSID
1822                 if (nhc->nhc_family == AF_INET) {
1823                         struct fib_nh *nh;
1824
1825                         nh = container_of(nhc, struct fib_nh, nh_common);
1826                         if (nh->nh_tclassid &&
1827                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1828                                 goto nla_put_failure;
1829                 }
1830 #endif
1831         } else {
1832                 if (fib_add_multipath(skb, fi) < 0)
1833                         goto nla_put_failure;
1834         }
1835
1836 offload:
1837         if (fri->offload)
1838                 rtm->rtm_flags |= RTM_F_OFFLOAD;
1839         if (fri->trap)
1840                 rtm->rtm_flags |= RTM_F_TRAP;
1841         if (fri->offload_failed)
1842                 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1843
1844         nlmsg_end(skb, nlh);
1845         return 0;
1846
1847 nla_put_failure:
1848         nlmsg_cancel(skb, nlh);
1849         return -EMSGSIZE;
1850 }
1851
1852 /*
1853  * Update FIB if:
1854  * - local address disappeared -> we must delete all the entries
1855  *   referring to it.
1856  * - device went down -> we must shutdown all nexthops going via it.
1857  */
1858 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1859 {
1860         int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1861         struct net *net = dev_net(dev);
1862         struct hlist_head *head;
1863         struct fib_info *fi;
1864         int ret = 0;
1865
1866         if (!fib_info_laddrhash || local == 0)
1867                 return 0;
1868
1869         head = fib_info_laddrhash_bucket(net, local);
1870         hlist_for_each_entry(fi, head, fib_lhash) {
1871                 if (!net_eq(fi->fib_net, net) ||
1872                     fi->fib_tb_id != tb_id)
1873                         continue;
1874                 if (fi->fib_prefsrc == local) {
1875                         fi->fib_flags |= RTNH_F_DEAD;
1876                         ret++;
1877                 }
1878         }
1879         return ret;
1880 }
1881
1882 static int call_fib_nh_notifiers(struct fib_nh *nh,
1883                                  enum fib_event_type event_type)
1884 {
1885         bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1886         struct fib_nh_notifier_info info = {
1887                 .fib_nh = nh,
1888         };
1889
1890         switch (event_type) {
1891         case FIB_EVENT_NH_ADD:
1892                 if (nh->fib_nh_flags & RTNH_F_DEAD)
1893                         break;
1894                 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1895                         break;
1896                 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1897                                            &info.info);
1898         case FIB_EVENT_NH_DEL:
1899                 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1900                     (nh->fib_nh_flags & RTNH_F_DEAD))
1901                         return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1902                                                    event_type, &info.info);
1903                 break;
1904         default:
1905                 break;
1906         }
1907
1908         return NOTIFY_DONE;
1909 }
1910
1911 /* Update the PMTU of exceptions when:
1912  * - the new MTU of the first hop becomes smaller than the PMTU
1913  * - the old MTU was the same as the PMTU, and it limited discovery of
1914  *   larger MTUs on the path. With that limit raised, we can now
1915  *   discover larger MTUs
1916  * A special case is locked exceptions, for which the PMTU is smaller
1917  * than the minimal accepted PMTU:
1918  * - if the new MTU is greater than the PMTU, don't make any change
1919  * - otherwise, unlock and set PMTU
1920  */
1921 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1922 {
1923         struct fnhe_hash_bucket *bucket;
1924         int i;
1925
1926         bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1927         if (!bucket)
1928                 return;
1929
1930         for (i = 0; i < FNHE_HASH_SIZE; i++) {
1931                 struct fib_nh_exception *fnhe;
1932
1933                 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1934                      fnhe;
1935                      fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1936                         if (fnhe->fnhe_mtu_locked) {
1937                                 if (new <= fnhe->fnhe_pmtu) {
1938                                         fnhe->fnhe_pmtu = new;
1939                                         fnhe->fnhe_mtu_locked = false;
1940                                 }
1941                         } else if (new < fnhe->fnhe_pmtu ||
1942                                    orig == fnhe->fnhe_pmtu) {
1943                                 fnhe->fnhe_pmtu = new;
1944                         }
1945                 }
1946         }
1947 }
1948
1949 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1950 {
1951         struct hlist_head *head = fib_info_devhash_bucket(dev);
1952         struct fib_nh *nh;
1953
1954         hlist_for_each_entry(nh, head, nh_hash) {
1955                 if (nh->fib_nh_dev == dev)
1956                         fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1957         }
1958 }
1959
1960 /* Event              force Flags           Description
1961  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1962  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1963  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1964  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1965  *
1966  * only used when fib_nh is built into fib_info
1967  */
1968 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1969 {
1970         struct hlist_head *head = fib_info_devhash_bucket(dev);
1971         struct fib_info *prev_fi = NULL;
1972         int scope = RT_SCOPE_NOWHERE;
1973         struct fib_nh *nh;
1974         int ret = 0;
1975
1976         if (force)
1977                 scope = -1;
1978
1979         hlist_for_each_entry(nh, head, nh_hash) {
1980                 struct fib_info *fi = nh->nh_parent;
1981                 int dead;
1982
1983                 BUG_ON(!fi->fib_nhs);
1984                 if (nh->fib_nh_dev != dev || fi == prev_fi)
1985                         continue;
1986                 prev_fi = fi;
1987                 dead = 0;
1988                 change_nexthops(fi) {
1989                         if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1990                                 dead++;
1991                         else if (nexthop_nh->fib_nh_dev == dev &&
1992                                  nexthop_nh->fib_nh_scope != scope) {
1993                                 switch (event) {
1994                                 case NETDEV_DOWN:
1995                                 case NETDEV_UNREGISTER:
1996                                         nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1997                                         fallthrough;
1998                                 case NETDEV_CHANGE:
1999                                         nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2000                                         break;
2001                                 }
2002                                 call_fib_nh_notifiers(nexthop_nh,
2003                                                       FIB_EVENT_NH_DEL);
2004                                 dead++;
2005                         }
2006 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2007                         if (event == NETDEV_UNREGISTER &&
2008                             nexthop_nh->fib_nh_dev == dev) {
2009                                 dead = fi->fib_nhs;
2010                                 break;
2011                         }
2012 #endif
2013                 } endfor_nexthops(fi)
2014                 if (dead == fi->fib_nhs) {
2015                         switch (event) {
2016                         case NETDEV_DOWN:
2017                         case NETDEV_UNREGISTER:
2018                                 fi->fib_flags |= RTNH_F_DEAD;
2019                                 fallthrough;
2020                         case NETDEV_CHANGE:
2021                                 fi->fib_flags |= RTNH_F_LINKDOWN;
2022                                 break;
2023                         }
2024                         ret++;
2025                 }
2026
2027                 fib_rebalance(fi);
2028         }
2029
2030         return ret;
2031 }
2032
2033 /* Must be invoked inside of an RCU protected region.  */
2034 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2035 {
2036         struct fib_info *fi = NULL, *last_resort = NULL;
2037         struct hlist_head *fa_head = res->fa_head;
2038         struct fib_table *tb = res->table;
2039         u8 slen = 32 - res->prefixlen;
2040         int order = -1, last_idx = -1;
2041         struct fib_alias *fa, *fa1 = NULL;
2042         u32 last_prio = res->fi->fib_priority;
2043         dscp_t last_dscp = 0;
2044
2045         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2046                 struct fib_info *next_fi = fa->fa_info;
2047                 struct fib_nh_common *nhc;
2048
2049                 if (fa->fa_slen != slen)
2050                         continue;
2051                 if (fa->fa_dscp &&
2052                     fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2053                         continue;
2054                 if (fa->tb_id != tb->tb_id)
2055                         continue;
2056                 if (next_fi->fib_priority > last_prio &&
2057                     fa->fa_dscp == last_dscp) {
2058                         if (last_dscp)
2059                                 continue;
2060                         break;
2061                 }
2062                 if (next_fi->fib_flags & RTNH_F_DEAD)
2063                         continue;
2064                 last_dscp = fa->fa_dscp;
2065                 last_prio = next_fi->fib_priority;
2066
2067                 if (next_fi->fib_scope != res->scope ||
2068                     fa->fa_type != RTN_UNICAST)
2069                         continue;
2070
2071                 nhc = fib_info_nhc(next_fi, 0);
2072                 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2073                         continue;
2074
2075                 fib_alias_accessed(fa);
2076
2077                 if (!fi) {
2078                         if (next_fi != res->fi)
2079                                 break;
2080                         fa1 = fa;
2081                 } else if (!fib_detect_death(fi, order, &last_resort,
2082                                              &last_idx, fa1->fa_default)) {
2083                         fib_result_assign(res, fi);
2084                         fa1->fa_default = order;
2085                         goto out;
2086                 }
2087                 fi = next_fi;
2088                 order++;
2089         }
2090
2091         if (order <= 0 || !fi) {
2092                 if (fa1)
2093                         fa1->fa_default = -1;
2094                 goto out;
2095         }
2096
2097         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2098                               fa1->fa_default)) {
2099                 fib_result_assign(res, fi);
2100                 fa1->fa_default = order;
2101                 goto out;
2102         }
2103
2104         if (last_idx >= 0)
2105                 fib_result_assign(res, last_resort);
2106         fa1->fa_default = last_idx;
2107 out:
2108         return;
2109 }
2110
2111 /*
2112  * Dead device goes up. We wake up dead nexthops.
2113  * It takes sense only on multipath routes.
2114  *
2115  * only used when fib_nh is built into fib_info
2116  */
2117 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2118 {
2119         struct fib_info *prev_fi;
2120         struct hlist_head *head;
2121         struct fib_nh *nh;
2122         int ret;
2123
2124         if (!(dev->flags & IFF_UP))
2125                 return 0;
2126
2127         if (nh_flags & RTNH_F_DEAD) {
2128                 unsigned int flags = dev_get_flags(dev);
2129
2130                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2131                         nh_flags |= RTNH_F_LINKDOWN;
2132         }
2133
2134         prev_fi = NULL;
2135         head = fib_info_devhash_bucket(dev);
2136         ret = 0;
2137
2138         hlist_for_each_entry(nh, head, nh_hash) {
2139                 struct fib_info *fi = nh->nh_parent;
2140                 int alive;
2141
2142                 BUG_ON(!fi->fib_nhs);
2143                 if (nh->fib_nh_dev != dev || fi == prev_fi)
2144                         continue;
2145
2146                 prev_fi = fi;
2147                 alive = 0;
2148                 change_nexthops(fi) {
2149                         if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2150                                 alive++;
2151                                 continue;
2152                         }
2153                         if (!nexthop_nh->fib_nh_dev ||
2154                             !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2155                                 continue;
2156                         if (nexthop_nh->fib_nh_dev != dev ||
2157                             !__in_dev_get_rtnl(dev))
2158                                 continue;
2159                         alive++;
2160                         nexthop_nh->fib_nh_flags &= ~nh_flags;
2161                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2162                 } endfor_nexthops(fi)
2163
2164                 if (alive > 0) {
2165                         fi->fib_flags &= ~nh_flags;
2166                         ret++;
2167                 }
2168
2169                 fib_rebalance(fi);
2170         }
2171
2172         return ret;
2173 }
2174
2175 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2176 static bool fib_good_nh(const struct fib_nh *nh)
2177 {
2178         int state = NUD_REACHABLE;
2179
2180         if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2181                 struct neighbour *n;
2182
2183                 rcu_read_lock_bh();
2184
2185                 if (likely(nh->fib_nh_gw_family == AF_INET))
2186                         n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2187                                                    (__force u32)nh->fib_nh_gw4);
2188                 else if (nh->fib_nh_gw_family == AF_INET6)
2189                         n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2190                                                            &nh->fib_nh_gw6);
2191                 else
2192                         n = NULL;
2193                 if (n)
2194                         state = n->nud_state;
2195
2196                 rcu_read_unlock_bh();
2197         }
2198
2199         return !!(state & NUD_VALID);
2200 }
2201
2202 void fib_select_multipath(struct fib_result *res, int hash)
2203 {
2204         struct fib_info *fi = res->fi;
2205         struct net *net = fi->fib_net;
2206         bool first = false;
2207
2208         if (unlikely(res->fi->nh)) {
2209                 nexthop_path_fib_result(res, hash);
2210                 return;
2211         }
2212
2213         change_nexthops(fi) {
2214                 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2215                         if (!fib_good_nh(nexthop_nh))
2216                                 continue;
2217                         if (!first) {
2218                                 res->nh_sel = nhsel;
2219                                 res->nhc = &nexthop_nh->nh_common;
2220                                 first = true;
2221                         }
2222                 }
2223
2224                 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2225                         continue;
2226
2227                 res->nh_sel = nhsel;
2228                 res->nhc = &nexthop_nh->nh_common;
2229                 return;
2230         } endfor_nexthops(fi);
2231 }
2232 #endif
2233
2234 void fib_select_path(struct net *net, struct fib_result *res,
2235                      struct flowi4 *fl4, const struct sk_buff *skb)
2236 {
2237         if (fl4->flowi4_oif)
2238                 goto check_saddr;
2239
2240 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2241         if (fib_info_num_path(res->fi) > 1) {
2242                 int h = fib_multipath_hash(net, fl4, skb, NULL);
2243
2244                 fib_select_multipath(res, h);
2245         }
2246         else
2247 #endif
2248         if (!res->prefixlen &&
2249             res->table->tb_num_default > 1 &&
2250             res->type == RTN_UNICAST)
2251                 fib_select_default(fl4, res);
2252
2253 check_saddr:
2254         if (!fl4->saddr)
2255                 fl4->saddr = fib_result_prefsrc(net, res);
2256 }