net/ipv4/fib_semantics.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              IPv4 Forwarding Information Base: semantics.
   7  *
   8  * Authors:     Alexey Kuznetsov, <[email protected]>
   9  *
  10  *              This program is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/uaccess.h>
  17 #include <linux/bitops.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/mm.h>
  22 #include <linux/string.h>
  23 #include <linux/socket.h>
  24 #include <linux/sockios.h>
  25 #include <linux/errno.h>
  26 #include <linux/in.h>
  27 #include <linux/inet.h>
  28 #include <linux/inetdevice.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/init.h>
  34 #include <linux/slab.h>
  35 #include <linux/netlink.h>
  36
  37 #include <net/arp.h>
  38 #include <net/ip.h>
  39 #include <net/protocol.h>
  40 #include <net/route.h>
  41 #include <net/tcp.h>
  42 #include <net/sock.h>
  43 #include <net/ip_fib.h>
  44 #include <net/netlink.h>
  45 #include <net/nexthop.h>
  46 #include <net/lwtunnel.h>
  47 #include <net/fib_notifier.h>
  48
  49 #include "fib_lookup.h"
  50
  51 static DEFINE_SPINLOCK(fib_info_lock);
  52 static struct hlist_head *fib_info_hash;
  53 static struct hlist_head *fib_info_laddrhash;
  54 static unsigned int fib_info_hash_size;
  55 static unsigned int fib_info_cnt;
  56
  57 #define DEVINDEX_HASHBITS 8
  58 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  59 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  60
  61 #ifdef CONFIG_IP_ROUTE_MULTIPATH
  62
  63 #define for_nexthops(fi) {                                              \
  64         int nhsel; const struct fib_nh *nh;                             \
  65         for (nhsel = 0, nh = (fi)->fib_nh;                              \
  66              nhsel < (fi)->fib_nhs;                                     \
  67              nh++, nhsel++)
  68
  69 #define change_nexthops(fi) {                                           \
  70         int nhsel; struct fib_nh *nexthop_nh;                           \
  71         for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh);   \
  72              nhsel < (fi)->fib_nhs;                                     \
  73              nexthop_nh++, nhsel++)
  74
  75 #else /* CONFIG_IP_ROUTE_MULTIPATH */
  76
  77 /* Hope, that gcc will optimize it to get rid of dummy loop */
  78
  79 #define for_nexthops(fi) {                                              \
  80         int nhsel; const struct fib_nh *nh = (fi)->fib_nh;              \
  81         for (nhsel = 0; nhsel < 1; nhsel++)
  82
  83 #define change_nexthops(fi) {                                           \
  84         int nhsel;                                                      \
  85         struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);    \
  86         for (nhsel = 0; nhsel < 1; nhsel++)
  87
  88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
  89
  90 #define endfor_nexthops(fi) }
  91
  92
  93 const struct fib_prop fib_props[RTN_MAX + 1] = {
  94         [RTN_UNSPEC] = {
  95                 .error  = 0,
  96                 .scope  = RT_SCOPE_NOWHERE,
  97         },
  98         [RTN_UNICAST] = {
  99                 .error  = 0,
 100                 .scope  = RT_SCOPE_UNIVERSE,
 101         },
 102         [RTN_LOCAL] = {
 103                 .error  = 0,
 104                 .scope  = RT_SCOPE_HOST,
 105         },
 106         [RTN_BROADCAST] = {
 107                 .error  = 0,
 108                 .scope  = RT_SCOPE_LINK,
 109         },
 110         [RTN_ANYCAST] = {
 111                 .error  = 0,
 112                 .scope  = RT_SCOPE_LINK,
 113         },
 114         [RTN_MULTICAST] = {
 115                 .error  = 0,
 116                 .scope  = RT_SCOPE_UNIVERSE,
 117         },
 118         [RTN_BLACKHOLE] = {
 119                 .error  = -EINVAL,
 120                 .scope  = RT_SCOPE_UNIVERSE,
 121         },
 122         [RTN_UNREACHABLE] = {
 123                 .error  = -EHOSTUNREACH,
 124                 .scope  = RT_SCOPE_UNIVERSE,
 125         },
 126         [RTN_PROHIBIT] = {
 127                 .error  = -EACCES,
 128                 .scope  = RT_SCOPE_UNIVERSE,
 129         },
 130         [RTN_THROW] = {
 131                 .error  = -EAGAIN,
 132                 .scope  = RT_SCOPE_UNIVERSE,
 133         },
 134         [RTN_NAT] = {
 135                 .error  = -EINVAL,
 136                 .scope  = RT_SCOPE_NOWHERE,
 137         },
 138         [RTN_XRESOLVE] = {
 139                 .error  = -EINVAL,
 140                 .scope  = RT_SCOPE_NOWHERE,
 141         },
 142 };
 143
 144 static void rt_fibinfo_free(struct rtable __rcu **rtp)
 145 {
 146         struct rtable *rt = rcu_dereference_protected(*rtp, 1);
 147
 148         if (!rt)
 149                 return;
 150
 151         /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
 152          * because we waited an RCU grace period before calling
 153          * free_fib_info_rcu()
 154          */
 155
 156         dst_dev_put(&rt->dst);
 157         dst_release_immediate(&rt->dst);
 158 }
 159
 160 static void free_nh_exceptions(struct fib_nh *nh)
 161 {
 162         struct fnhe_hash_bucket *hash;
 163         int i;
 164
 165         hash = rcu_dereference_protected(nh->nh_exceptions, 1);
 166         if (!hash)
 167                 return;
 168         for (i = 0; i < FNHE_HASH_SIZE; i++) {
 169                 struct fib_nh_exception *fnhe;
 170
 171                 fnhe = rcu_dereference_protected(hash[i].chain, 1);
 172                 while (fnhe) {
 173                         struct fib_nh_exception *next;
 174
 175                         next = rcu_dereference_protected(fnhe->fnhe_next, 1);
 176
 177                         rt_fibinfo_free(&fnhe->fnhe_rth_input);
 178                         rt_fibinfo_free(&fnhe->fnhe_rth_output);
 179
 180                         kfree(fnhe);
 181
 182                         fnhe = next;
 183                 }
 184         }
 185         kfree(hash);
 186 }
 187
 188 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 189 {
 190         int cpu;
 191
 192         if (!rtp)
 193                 return;
 194
 195         for_each_possible_cpu(cpu) {
 196                 struct rtable *rt;
 197
 198                 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
 199                 if (rt) {
 200                         dst_dev_put(&rt->dst);
 201                         dst_release_immediate(&rt->dst);
 202                 }
 203         }
 204         free_percpu(rtp);
 205 }
 206
 207 /* Release a nexthop info record */
 208 static void free_fib_info_rcu(struct rcu_head *head)
 209 {
 210         struct fib_info *fi = container_of(head, struct fib_info, rcu);
 211         struct dst_metrics *m;
 212
 213         change_nexthops(fi) {
 214                 if (nexthop_nh->nh_dev)
 215                         dev_put(nexthop_nh->nh_dev);
 216                 lwtstate_put(nexthop_nh->nh_lwtstate);
 217                 free_nh_exceptions(nexthop_nh);
 218                 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
 219                 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
 220         } endfor_nexthops(fi);
 221
 222         m = fi->fib_metrics;
 223         if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
 224                 kfree(m);
 225         kfree(fi);
 226 }
 227
 228 void free_fib_info(struct fib_info *fi)
 229 {
 230         if (fi->fib_dead == 0) {
 231                 pr_warn("Freeing alive fib_info %p\n", fi);
 232                 return;
 233         }
 234         fib_info_cnt--;
 235 #ifdef CONFIG_IP_ROUTE_CLASSID
 236         change_nexthops(fi) {
 237                 if (nexthop_nh->nh_tclassid)
 238                         fi->fib_net->ipv4.fib_num_tclassid_users--;
 239         } endfor_nexthops(fi);
 240 #endif
 241         call_rcu(&fi->rcu, free_fib_info_rcu);
 242 }
 243 EXPORT_SYMBOL_GPL(free_fib_info);
 244
 245 void fib_release_info(struct fib_info *fi)
 246 {
 247         spin_lock_bh(&fib_info_lock);
 248         if (fi && --fi->fib_treeref == 0) {
 249                 hlist_del(&fi->fib_hash);
 250                 if (fi->fib_prefsrc)
 251                         hlist_del(&fi->fib_lhash);
 252                 change_nexthops(fi) {
 253                         if (!nexthop_nh->nh_dev)
 254                                 continue;
 255                         hlist_del(&nexthop_nh->nh_hash);
 256                 } endfor_nexthops(fi)
 257                 fi->fib_dead = 1;
 258                 fib_info_put(fi);
 259         }
 260         spin_unlock_bh(&fib_info_lock);
 261 }
 262
 263 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
 264 {
 265         const struct fib_nh *onh = ofi->fib_nh;
 266
 267         for_nexthops(fi) {
 268                 if (nh->nh_oif != onh->nh_oif ||
 269                     nh->nh_gw  != onh->nh_gw ||
 270                     nh->nh_scope != onh->nh_scope ||
 271 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 272                     nh->nh_weight != onh->nh_weight ||
 273 #endif
 274 #ifdef CONFIG_IP_ROUTE_CLASSID
 275                     nh->nh_tclassid != onh->nh_tclassid ||
 276 #endif
 277                     lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
 278                     ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
 279                         return -1;
 280                 onh++;
 281         } endfor_nexthops(fi);
 282         return 0;
 283 }
 284
 285 static inline unsigned int fib_devindex_hashfn(unsigned int val)
 286 {
 287         unsigned int mask = DEVINDEX_HASHSIZE - 1;
 288
 289         return (val ^
 290                 (val >> DEVINDEX_HASHBITS) ^
 291                 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
 292 }
 293
 294 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
 295 {
 296         unsigned int mask = (fib_info_hash_size - 1);
 297         unsigned int val = fi->fib_nhs;
 298
 299         val ^= (fi->fib_protocol << 8) | fi->fib_scope;
 300         val ^= (__force u32)fi->fib_prefsrc;
 301         val ^= fi->fib_priority;
 302         for_nexthops(fi) {
 303                 val ^= fib_devindex_hashfn(nh->nh_oif);
 304         } endfor_nexthops(fi)
 305
 306         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 307 }
 308
 309 static struct fib_info *fib_find_info(const struct fib_info *nfi)
 310 {
 311         struct hlist_head *head;
 312         struct fib_info *fi;
 313         unsigned int hash;
 314
 315         hash = fib_info_hashfn(nfi);
 316         head = &fib_info_hash[hash];
 317
 318         hlist_for_each_entry(fi, head, fib_hash) {
 319                 if (!net_eq(fi->fib_net, nfi->fib_net))
 320                         continue;
 321                 if (fi->fib_nhs != nfi->fib_nhs)
 322                         continue;
 323                 if (nfi->fib_protocol == fi->fib_protocol &&
 324                     nfi->fib_scope == fi->fib_scope &&
 325                     nfi->fib_prefsrc == fi->fib_prefsrc &&
 326                     nfi->fib_priority == fi->fib_priority &&
 327                     nfi->fib_type == fi->fib_type &&
 328                     memcmp(nfi->fib_metrics, fi->fib_metrics,
 329                            sizeof(u32) * RTAX_MAX) == 0 &&
 330                     !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 331                     (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
 332                         return fi;
 333         }
 334
 335         return NULL;
 336 }
 337
 338 /* Check, that the gateway is already configured.
 339  * Used only by redirect accept routine.
 340  */
 341 int ip_fib_check_default(__be32 gw, struct net_device *dev)
 342 {
 343         struct hlist_head *head;
 344         struct fib_nh *nh;
 345         unsigned int hash;
 346
 347         spin_lock(&fib_info_lock);
 348
 349         hash = fib_devindex_hashfn(dev->ifindex);
 350         head = &fib_info_devhash[hash];
 351         hlist_for_each_entry(nh, head, nh_hash) {
 352                 if (nh->nh_dev == dev &&
 353                     nh->nh_gw == gw &&
 354                     !(nh->nh_flags & RTNH_F_DEAD)) {
 355                         spin_unlock(&fib_info_lock);
 356                         return 0;
 357                 }
 358         }
 359
 360         spin_unlock(&fib_info_lock);
 361
 362         return -1;
 363 }
 364
 365 static inline size_t fib_nlmsg_size(struct fib_info *fi)
 366 {
 367         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 368                          + nla_total_size(4) /* RTA_TABLE */
 369                          + nla_total_size(4) /* RTA_DST */
 370                          + nla_total_size(4) /* RTA_PRIORITY */
 371                          + nla_total_size(4) /* RTA_PREFSRC */
 372                          + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 373
 374         /* space for nested metrics */
 375         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 376
 377         if (fi->fib_nhs) {
 378                 size_t nh_encapsize = 0;
 379                 /* Also handles the special case fib_nhs == 1 */
 380
 381                 /* each nexthop is packed in an attribute */
 382                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 383
 384                 /* may contain flow and gateway attribute */
 385                 nhsize += 2 * nla_total_size(4);
 386
 387                 /* grab encap info */
 388                 for_nexthops(fi) {
 389                         if (nh->nh_lwtstate) {
 390                                 /* RTA_ENCAP_TYPE */
 391                                 nh_encapsize += lwtunnel_get_encap_size(
 392                                                 nh->nh_lwtstate);
 393                                 /* RTA_ENCAP */
 394                                 nh_encapsize +=  nla_total_size(2);
 395                         }
 396                 } endfor_nexthops(fi);
 397
 398                 /* all nexthops are packed in a nested attribute */
 399                 payload += nla_total_size((fi->fib_nhs * nhsize) +
 400                                           nh_encapsize);
 401
 402         }
 403
 404         return payload;
 405 }
 406
 407 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 408                int dst_len, u32 tb_id, const struct nl_info *info,
 409                unsigned int nlm_flags)
 410 {
 411         struct sk_buff *skb;
 412         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 413         int err = -ENOBUFS;
 414
 415         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 416         if (!skb)
 417                 goto errout;
 418
 419         err = fib_dump_info(skb, info->portid, seq, event, tb_id,
 420                             fa->fa_type, key, dst_len,
 421                             fa->fa_tos, fa->fa_info, nlm_flags);
 422         if (err < 0) {
 423                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 424                 WARN_ON(err == -EMSGSIZE);
 425                 kfree_skb(skb);
 426                 goto errout;
 427         }
 428         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 429                     info->nlh, GFP_KERNEL);
 430         return;
 431 errout:
 432         if (err < 0)
 433                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 434 }
 435
 436 static int fib_detect_death(struct fib_info *fi, int order,
 437                             struct fib_info **last_resort, int *last_idx,
 438                             int dflt)
 439 {
 440         struct neighbour *n;
 441         int state = NUD_NONE;
 442
 443         n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
 444         if (n) {
 445                 state = n->nud_state;
 446                 neigh_release(n);
 447         } else {
 448                 return 0;
 449         }
 450         if (state == NUD_REACHABLE)
 451                 return 0;
 452         if ((state & NUD_VALID) && order != dflt)
 453                 return 0;
 454         if ((state & NUD_VALID) ||
 455             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 456                 *last_resort = fi;
 457                 *last_idx = order;
 458         }
 459         return 1;
 460 }
 461
 462 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 463
 464 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 465                               struct netlink_ext_ack *extack)
 466 {
 467         int nhs = 0;
 468
 469         while (rtnh_ok(rtnh, remaining)) {
 470                 nhs++;
 471                 rtnh = rtnh_next(rtnh, &remaining);
 472         }
 473
 474         /* leftover implies invalid nexthop configuration, discard it */
 475         if (remaining > 0) {
 476                 NL_SET_ERR_MSG(extack,
 477                                "Invalid nexthop configuration - extra data after nexthops");
 478                 nhs = 0;
 479         }
 480
 481         return nhs;
 482 }
 483
 484 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 485                        int remaining, struct fib_config *cfg,
 486                        struct netlink_ext_ack *extack)
 487 {
 488         int ret;
 489
 490         change_nexthops(fi) {
 491                 int attrlen;
 492
 493                 if (!rtnh_ok(rtnh, remaining)) {
 494                         NL_SET_ERR_MSG(extack,
 495                                        "Invalid nexthop configuration - extra data after nexthop");
 496                         return -EINVAL;
 497                 }
 498
 499                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 500                         NL_SET_ERR_MSG(extack,
 501                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 502                         return -EINVAL;
 503                 }
 504
 505                 nexthop_nh->nh_flags =
 506                         (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 507                 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
 508                 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
 509
 510                 attrlen = rtnh_attrlen(rtnh);
 511                 if (attrlen > 0) {
 512                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
 513
 514                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 515                         nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
 516 #ifdef CONFIG_IP_ROUTE_CLASSID
 517                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 518                         nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
 519                         if (nexthop_nh->nh_tclassid)
 520                                 fi->fib_net->ipv4.fib_num_tclassid_users++;
 521 #endif
 522                         nla = nla_find(attrs, attrlen, RTA_ENCAP);
 523                         if (nla) {
 524                                 struct lwtunnel_state *lwtstate;
 525                                 struct nlattr *nla_entype;
 526
 527                                 nla_entype = nla_find(attrs, attrlen,
 528                                                       RTA_ENCAP_TYPE);
 529                                 if (!nla_entype) {
 530                                         NL_SET_BAD_ATTR(extack, nla);
 531                                         NL_SET_ERR_MSG(extack,
 532                                                        "Encap type is missing");
 533                                         goto err_inval;
 534                                 }
 535
 536                                 ret = lwtunnel_build_state(nla_get_u16(
 537                                                            nla_entype),
 538                                                            nla,  AF_INET, cfg,
 539                                                            &lwtstate, extack);
 540                                 if (ret)
 541                                         goto errout;
 542                                 nexthop_nh->nh_lwtstate =
 543                                         lwtstate_get(lwtstate);
 544                         }
 545                 }
 546
 547                 rtnh = rtnh_next(rtnh, &remaining);
 548         } endfor_nexthops(fi);
 549
 550         return 0;
 551
 552 err_inval:
 553         ret = -EINVAL;
 554
 555 errout:
 556         return ret;
 557 }
 558
 559 static void fib_rebalance(struct fib_info *fi)
 560 {
 561         int total;
 562         int w;
 563         struct in_device *in_dev;
 564
 565         if (fi->fib_nhs < 2)
 566                 return;
 567
 568         total = 0;
 569         for_nexthops(fi) {
 570                 if (nh->nh_flags & RTNH_F_DEAD)
 571                         continue;
 572
 573                 in_dev = __in_dev_get_rtnl(nh->nh_dev);
 574
 575                 if (in_dev &&
 576                     IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
 577                     nh->nh_flags & RTNH_F_LINKDOWN)
 578                         continue;
 579
 580                 total += nh->nh_weight;
 581         } endfor_nexthops(fi);
 582
 583         w = 0;
 584         change_nexthops(fi) {
 585                 int upper_bound;
 586
 587                 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
 588
 589                 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
 590                         upper_bound = -1;
 591                 } else if (in_dev &&
 592                            IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
 593                            nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
 594                         upper_bound = -1;
 595                 } else {
 596                         w += nexthop_nh->nh_weight;
 597                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 598                                                             total) - 1;
 599                 }
 600
 601                 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
 602         } endfor_nexthops(fi);
 603 }
 604 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 605
 606 #define fib_rebalance(fi) do { } while (0)
 607
 608 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 609
 610 static int fib_encap_match(u16 encap_type,
 611                            struct nlattr *encap,
 612                            const struct fib_nh *nh,
 613                            const struct fib_config *cfg,
 614                            struct netlink_ext_ack *extack)
 615 {
 616         struct lwtunnel_state *lwtstate;
 617         int ret, result = 0;
 618
 619         if (encap_type == LWTUNNEL_ENCAP_NONE)
 620                 return 0;
 621
 622         ret = lwtunnel_build_state(encap_type, encap, AF_INET,
 623                                    cfg, &lwtstate, extack);
 624         if (!ret) {
 625                 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
 626                 lwtstate_free(lwtstate);
 627         }
 628
 629         return result;
 630 }
 631
 632 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
 633                  struct netlink_ext_ack *extack)
 634 {
 635 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 636         struct rtnexthop *rtnh;
 637         int remaining;
 638 #endif
 639
 640         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 641                 return 1;
 642
 643         if (cfg->fc_oif || cfg->fc_gw) {
 644                 if (cfg->fc_encap) {
 645                         if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
 646                                             fi->fib_nh, cfg, extack))
 647                                 return 1;
 648                 }
 649                 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
 650                     (!cfg->fc_gw  || cfg->fc_gw == fi->fib_nh->nh_gw))
 651                         return 0;
 652                 return 1;
 653         }
 654
 655 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 656         if (!cfg->fc_mp)
 657                 return 0;
 658
 659         rtnh = cfg->fc_mp;
 660         remaining = cfg->fc_mp_len;
 661
 662         for_nexthops(fi) {
 663                 int attrlen;
 664
 665                 if (!rtnh_ok(rtnh, remaining))
 666                         return -EINVAL;
 667
 668                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
 669                         return 1;
 670
 671                 attrlen = rtnh_attrlen(rtnh);
 672                 if (attrlen > 0) {
 673                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
 674
 675                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 676                         if (nla && nla_get_in_addr(nla) != nh->nh_gw)
 677                                 return 1;
 678 #ifdef CONFIG_IP_ROUTE_CLASSID
 679                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 680                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 681                                 return 1;
 682 #endif
 683                 }
 684
 685                 rtnh = rtnh_next(rtnh, &remaining);
 686         } endfor_nexthops(fi);
 687 #endif
 688         return 0;
 689 }
 690
 691 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 692 {
 693         struct nlattr *nla;
 694         int remaining;
 695
 696         if (!cfg->fc_mx)
 697                 return true;
 698
 699         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 700                 int type = nla_type(nla);
 701                 u32 fi_val, val;
 702
 703                 if (!type)
 704                         continue;
 705                 if (type > RTAX_MAX)
 706                         return false;
 707
 708                 if (type == RTAX_CC_ALGO) {
 709                         char tmp[TCP_CA_NAME_MAX];
 710                         bool ecn_ca = false;
 711
 712                         nla_strlcpy(tmp, nla, sizeof(tmp));
 713                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 714                 } else {
 715                         val = nla_get_u32(nla);
 716                 }
 717
 718                 fi_val = fi->fib_metrics->metrics[type - 1];
 719                 if (type == RTAX_FEATURES)
 720                         fi_val &= ~DST_FEATURE_ECN_CA;
 721
 722                 if (fi_val != val)
 723                         return false;
 724         }
 725
 726         return true;
 727 }
 728
 729
 730 /*
 731  * Picture
 732  * -------
 733  *
 734  * Semantics of nexthop is very messy by historical reasons.
 735  * We have to take into account, that:
 736  * a) gateway can be actually local interface address,
 737  *    so that gatewayed route is direct.
 738  * b) gateway must be on-link address, possibly
 739  *    described not by an ifaddr, but also by a direct route.
 740  * c) If both gateway and interface are specified, they should not
 741  *    contradict.
 742  * d) If we use tunnel routes, gateway could be not on-link.
 743  *
 744  * Attempt to reconcile all of these (alas, self-contradictory) conditions
 745  * results in pretty ugly and hairy code with obscure logic.
 746  *
 747  * I chose to generalized it instead, so that the size
 748  * of code does not increase practically, but it becomes
 749  * much more general.
 750  * Every prefix is assigned a "scope" value: "host" is local address,
 751  * "link" is direct route,
 752  * [ ... "site" ... "interior" ... ]
 753  * and "universe" is true gateway route with global meaning.
 754  *
 755  * Every prefix refers to a set of "nexthop"s (gw, oif),
 756  * where gw must have narrower scope. This recursion stops
 757  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
 758  * which means that gw is forced to be on link.
 759  *
 760  * Code is still hairy, but now it is apparently logically
 761  * consistent and very flexible. F.e. as by-product it allows
 762  * to co-exists in peace independent exterior and interior
 763  * routing processes.
 764  *
 765  * Normally it looks as following.
 766  *
 767  * {universe prefix}  -> (gw, oif) [scope link]
 768  *                |
 769  *                |-> {link prefix} -> (gw, oif) [scope local]
 770  *                                      |
 771  *                                      |-> {local prefix} (terminal node)
 772  */
 773 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
 774                         struct netlink_ext_ack *extack)
 775 {
 776         int err = 0;
 777         struct net *net;
 778         struct net_device *dev;
 779
 780         net = cfg->fc_nlinfo.nl_net;
 781         if (nh->nh_gw) {
 782                 struct fib_result res;
 783
 784                 if (nh->nh_flags & RTNH_F_ONLINK) {
 785                         unsigned int addr_type;
 786
 787                         if (cfg->fc_scope >= RT_SCOPE_LINK) {
 788                                 NL_SET_ERR_MSG(extack,
 789                                                "Nexthop has invalid scope");
 790                                 return -EINVAL;
 791                         }
 792                         dev = __dev_get_by_index(net, nh->nh_oif);
 793                         if (!dev)
 794                                 return -ENODEV;
 795                         if (!(dev->flags & IFF_UP)) {
 796                                 NL_SET_ERR_MSG(extack,
 797                                                "Nexthop device is not up");
 798                                 return -ENETDOWN;
 799                         }
 800                         addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
 801                         if (addr_type != RTN_UNICAST) {
 802                                 NL_SET_ERR_MSG(extack,
 803                                                "Nexthop has invalid gateway");
 804                                 return -EINVAL;
 805                         }
 806                         if (!netif_carrier_ok(dev))
 807                                 nh->nh_flags |= RTNH_F_LINKDOWN;
 808                         nh->nh_dev = dev;
 809                         dev_hold(dev);
 810                         nh->nh_scope = RT_SCOPE_LINK;
 811                         return 0;
 812                 }
 813                 rcu_read_lock();
 814                 {
 815                         struct fib_table *tbl = NULL;
 816                         struct flowi4 fl4 = {
 817                                 .daddr = nh->nh_gw,
 818                                 .flowi4_scope = cfg->fc_scope + 1,
 819                                 .flowi4_oif = nh->nh_oif,
 820                                 .flowi4_iif = LOOPBACK_IFINDEX,
 821                         };
 822
 823                         /* It is not necessary, but requires a bit of thinking */
 824                         if (fl4.flowi4_scope < RT_SCOPE_LINK)
 825                                 fl4.flowi4_scope = RT_SCOPE_LINK;
 826
 827                         if (cfg->fc_table)
 828                                 tbl = fib_get_table(net, cfg->fc_table);
 829
 830                         if (tbl)
 831                                 err = fib_table_lookup(tbl, &fl4, &res,
 832                                                        FIB_LOOKUP_IGNORE_LINKSTATE |
 833                                                        FIB_LOOKUP_NOREF);
 834
 835                         /* on error or if no table given do full lookup. This
 836                          * is needed for example when nexthops are in the local
 837                          * table rather than the given table
 838                          */
 839                         if (!tbl || err) {
 840                                 err = fib_lookup(net, &fl4, &res,
 841                                                  FIB_LOOKUP_IGNORE_LINKSTATE);
 842                         }
 843
 844                         if (err) {
 845                                 NL_SET_ERR_MSG(extack,
 846                                                "Nexthop has invalid gateway");
 847                                 rcu_read_unlock();
 848                                 return err;
 849                         }
 850                 }
 851                 err = -EINVAL;
 852                 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
 853                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
 854                         goto out;
 855                 }
 856                 nh->nh_scope = res.scope;
 857                 nh->nh_oif = FIB_RES_OIF(res);
 858                 nh->nh_dev = dev = FIB_RES_DEV(res);
 859                 if (!dev) {
 860                         NL_SET_ERR_MSG(extack,
 861                                        "No egress device for nexthop gateway");
 862                         goto out;
 863                 }
 864                 dev_hold(dev);
 865                 if (!netif_carrier_ok(dev))
 866                         nh->nh_flags |= RTNH_F_LINKDOWN;
 867                 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
 868         } else {
 869                 struct in_device *in_dev;
 870
 871                 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
 872                         NL_SET_ERR_MSG(extack,
 873                                        "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
 874                         return -EINVAL;
 875                 }
 876                 rcu_read_lock();
 877                 err = -ENODEV;
 878                 in_dev = inetdev_by_index(net, nh->nh_oif);
 879                 if (!in_dev)
 880                         goto out;
 881                 err = -ENETDOWN;
 882                 if (!(in_dev->dev->flags & IFF_UP)) {
 883                         NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
 884                         goto out;
 885                 }
 886                 nh->nh_dev = in_dev->dev;
 887                 dev_hold(nh->nh_dev);
 888                 nh->nh_scope = RT_SCOPE_HOST;
 889                 if (!netif_carrier_ok(nh->nh_dev))
 890                         nh->nh_flags |= RTNH_F_LINKDOWN;
 891                 err = 0;
 892         }
 893 out:
 894         rcu_read_unlock();
 895         return err;
 896 }
 897
 898 static inline unsigned int fib_laddr_hashfn(__be32 val)
 899 {
 900         unsigned int mask = (fib_info_hash_size - 1);
 901
 902         return ((__force u32)val ^
 903                 ((__force u32)val >> 7) ^
 904                 ((__force u32)val >> 14)) & mask;
 905 }
 906
 907 static struct hlist_head *fib_info_hash_alloc(int bytes)
 908 {
 909         if (bytes <= PAGE_SIZE)
 910                 return kzalloc(bytes, GFP_KERNEL);
 911         else
 912                 return (struct hlist_head *)
 913                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
 914                                          get_order(bytes));
 915 }
 916
 917 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
 918 {
 919         if (!hash)
 920                 return;
 921
 922         if (bytes <= PAGE_SIZE)
 923                 kfree(hash);
 924         else
 925                 free_pages((unsigned long) hash, get_order(bytes));
 926 }
 927
 928 static void fib_info_hash_move(struct hlist_head *new_info_hash,
 929                                struct hlist_head *new_laddrhash,
 930                                unsigned int new_size)
 931 {
 932         struct hlist_head *old_info_hash, *old_laddrhash;
 933         unsigned int old_size = fib_info_hash_size;
 934         unsigned int i, bytes;
 935
 936         spin_lock_bh(&fib_info_lock);
 937         old_info_hash = fib_info_hash;
 938         old_laddrhash = fib_info_laddrhash;
 939         fib_info_hash_size = new_size;
 940
 941         for (i = 0; i < old_size; i++) {
 942                 struct hlist_head *head = &fib_info_hash[i];
 943                 struct hlist_node *n;
 944                 struct fib_info *fi;
 945
 946                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
 947                         struct hlist_head *dest;
 948                         unsigned int new_hash;
 949
 950                         new_hash = fib_info_hashfn(fi);
 951                         dest = &new_info_hash[new_hash];
 952                         hlist_add_head(&fi->fib_hash, dest);
 953                 }
 954         }
 955         fib_info_hash = new_info_hash;
 956
 957         for (i = 0; i < old_size; i++) {
 958                 struct hlist_head *lhead = &fib_info_laddrhash[i];
 959                 struct hlist_node *n;
 960                 struct fib_info *fi;
 961
 962                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
 963                         struct hlist_head *ldest;
 964                         unsigned int new_hash;
 965
 966                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
 967                         ldest = &new_laddrhash[new_hash];
 968                         hlist_add_head(&fi->fib_lhash, ldest);
 969                 }
 970         }
 971         fib_info_laddrhash = new_laddrhash;
 972
 973         spin_unlock_bh(&fib_info_lock);
 974
 975         bytes = old_size * sizeof(struct hlist_head *);
 976         fib_info_hash_free(old_info_hash, bytes);
 977         fib_info_hash_free(old_laddrhash, bytes);
 978 }
 979
 980 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
 981 {
 982         nh->nh_saddr = inet_select_addr(nh->nh_dev,
 983                                         nh->nh_gw,
 984                                         nh->nh_parent->fib_scope);
 985         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
 986
 987         return nh->nh_saddr;
 988 }
 989
 990 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
 991 {
 992         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
 993             fib_prefsrc != cfg->fc_dst) {
 994                 u32 tb_id = cfg->fc_table;
 995                 int rc;
 996
 997                 if (tb_id == RT_TABLE_MAIN)
 998                         tb_id = RT_TABLE_LOCAL;
 999
1000                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1001                                           fib_prefsrc, tb_id);
1002
1003                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1004                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1005                                                   fib_prefsrc, RT_TABLE_LOCAL);
1006                 }
1007
1008                 if (rc != RTN_LOCAL)
1009                         return false;
1010         }
1011         return true;
1012 }
1013
1014 static int
1015 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
1016 {
1017         bool ecn_ca = false;
1018         struct nlattr *nla;
1019         int remaining;
1020
1021         if (!cfg->fc_mx)
1022                 return 0;
1023
1024         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1025                 int type = nla_type(nla);
1026                 u32 val;
1027
1028                 if (!type)
1029                         continue;
1030                 if (type > RTAX_MAX)
1031                         return -EINVAL;
1032
1033                 if (type == RTAX_CC_ALGO) {
1034                         char tmp[TCP_CA_NAME_MAX];
1035
1036                         nla_strlcpy(tmp, nla, sizeof(tmp));
1037                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1038                         if (val == TCP_CA_UNSPEC)
1039                                 return -EINVAL;
1040                 } else {
1041                         val = nla_get_u32(nla);
1042                 }
1043                 if (type == RTAX_ADVMSS && val > 65535 - 40)
1044                         val = 65535 - 40;
1045                 if (type == RTAX_MTU && val > 65535 - 15)
1046                         val = 65535 - 15;
1047                 if (type == RTAX_HOPLIMIT && val > 255)
1048                         val = 255;
1049                 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1050                         return -EINVAL;
1051                 fi->fib_metrics->metrics[type - 1] = val;
1052         }
1053
1054         if (ecn_ca)
1055                 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1056
1057         return 0;
1058 }
1059
1060 struct fib_info *fib_create_info(struct fib_config *cfg,
1061                                  struct netlink_ext_ack *extack)
1062 {
1063         int err;
1064         struct fib_info *fi = NULL;
1065         struct fib_info *ofi;
1066         int nhs = 1;
1067         struct net *net = cfg->fc_nlinfo.nl_net;
1068
1069         if (cfg->fc_type > RTN_MAX)
1070                 goto err_inval;
1071
1072         /* Fast check to catch the most weird cases */
1073         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1074                 NL_SET_ERR_MSG(extack, "Invalid scope");
1075                 goto err_inval;
1076         }
1077
1078         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1079                 NL_SET_ERR_MSG(extack,
1080                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1081                 goto err_inval;
1082         }
1083
1084 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1085         if (cfg->fc_mp) {
1086                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1087                 if (nhs == 0)
1088                         goto err_inval;
1089         }
1090 #endif
1091
1092         err = -ENOBUFS;
1093         if (fib_info_cnt >= fib_info_hash_size) {
1094                 unsigned int new_size = fib_info_hash_size << 1;
1095                 struct hlist_head *new_info_hash;
1096                 struct hlist_head *new_laddrhash;
1097                 unsigned int bytes;
1098
1099                 if (!new_size)
1100                         new_size = 16;
1101                 bytes = new_size * sizeof(struct hlist_head *);
1102                 new_info_hash = fib_info_hash_alloc(bytes);
1103                 new_laddrhash = fib_info_hash_alloc(bytes);
1104                 if (!new_info_hash || !new_laddrhash) {
1105                         fib_info_hash_free(new_info_hash, bytes);
1106                         fib_info_hash_free(new_laddrhash, bytes);
1107                 } else
1108                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1109
1110                 if (!fib_info_hash_size)
1111                         goto failure;
1112         }
1113
1114         fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1115         if (!fi)
1116                 goto failure;
1117         if (cfg->fc_mx) {
1118                 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1119                 if (unlikely(!fi->fib_metrics)) {
1120                         kfree(fi);
1121                         return ERR_PTR(err);
1122                 }
1123                 refcount_set(&fi->fib_metrics->refcnt, 1);
1124         } else {
1125                 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1126         }
1127         fib_info_cnt++;
1128         fi->fib_net = net;
1129         fi->fib_protocol = cfg->fc_protocol;
1130         fi->fib_scope = cfg->fc_scope;
1131         fi->fib_flags = cfg->fc_flags;
1132         fi->fib_priority = cfg->fc_priority;
1133         fi->fib_prefsrc = cfg->fc_prefsrc;
1134         fi->fib_type = cfg->fc_type;
1135         fi->fib_tb_id = cfg->fc_table;
1136
1137         fi->fib_nhs = nhs;
1138         change_nexthops(fi) {
1139                 nexthop_nh->nh_parent = fi;
1140                 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1141                 if (!nexthop_nh->nh_pcpu_rth_output)
1142                         goto failure;
1143         } endfor_nexthops(fi)
1144
1145         err = fib_convert_metrics(fi, cfg);
1146         if (err)
1147                 goto failure;
1148
1149         if (cfg->fc_mp) {
1150 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1151                 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1152                 if (err != 0)
1153                         goto failure;
1154                 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1155                         NL_SET_ERR_MSG(extack,
1156                                        "Nexthop device index does not match RTA_OIF");
1157                         goto err_inval;
1158                 }
1159                 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1160                         NL_SET_ERR_MSG(extack,
1161                                        "Nexthop gateway does not match RTA_GATEWAY");
1162                         goto err_inval;
1163                 }
1164 #ifdef CONFIG_IP_ROUTE_CLASSID
1165                 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1166                         NL_SET_ERR_MSG(extack,
1167                                        "Nexthop class id does not match RTA_FLOW");
1168                         goto err_inval;
1169                 }
1170 #endif
1171 #else
1172                 NL_SET_ERR_MSG(extack,
1173                                "Multipath support not enabled in kernel");
1174                 goto err_inval;
1175 #endif
1176         } else {
1177                 struct fib_nh *nh = fi->fib_nh;
1178
1179                 if (cfg->fc_encap) {
1180                         struct lwtunnel_state *lwtstate;
1181
1182                         if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1183                                 NL_SET_ERR_MSG(extack,
1184                                                "LWT encap type not specified");
1185                                 goto err_inval;
1186                         }
1187                         err = lwtunnel_build_state(cfg->fc_encap_type,
1188                                                    cfg->fc_encap, AF_INET, cfg,
1189                                                    &lwtstate, extack);
1190                         if (err)
1191                                 goto failure;
1192
1193                         nh->nh_lwtstate = lwtstate_get(lwtstate);
1194                 }
1195                 nh->nh_oif = cfg->fc_oif;
1196                 nh->nh_gw = cfg->fc_gw;
1197                 nh->nh_flags = cfg->fc_flags;
1198 #ifdef CONFIG_IP_ROUTE_CLASSID
1199                 nh->nh_tclassid = cfg->fc_flow;
1200                 if (nh->nh_tclassid)
1201                         fi->fib_net->ipv4.fib_num_tclassid_users++;
1202 #endif
1203 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1204                 nh->nh_weight = 1;
1205 #endif
1206         }
1207
1208         if (fib_props[cfg->fc_type].error) {
1209                 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1210                         NL_SET_ERR_MSG(extack,
1211                                        "Gateway, device and multipath can not be specified for this route type");
1212                         goto err_inval;
1213                 }
1214                 goto link_it;
1215         } else {
1216                 switch (cfg->fc_type) {
1217                 case RTN_UNICAST:
1218                 case RTN_LOCAL:
1219                 case RTN_BROADCAST:
1220                 case RTN_ANYCAST:
1221                 case RTN_MULTICAST:
1222                         break;
1223                 default:
1224                         NL_SET_ERR_MSG(extack, "Invalid route type");
1225                         goto err_inval;
1226                 }
1227         }
1228
1229         if (cfg->fc_scope > RT_SCOPE_HOST) {
1230                 NL_SET_ERR_MSG(extack, "Invalid scope");
1231                 goto err_inval;
1232         }
1233
1234         if (cfg->fc_scope == RT_SCOPE_HOST) {
1235                 struct fib_nh *nh = fi->fib_nh;
1236
1237                 /* Local address is added. */
1238                 if (nhs != 1) {
1239                         NL_SET_ERR_MSG(extack,
1240                                        "Route with host scope can not have multiple nexthops");
1241                         goto err_inval;
1242                 }
1243                 if (nh->nh_gw) {
1244                         NL_SET_ERR_MSG(extack,
1245                                        "Route with host scope can not have a gateway");
1246                         goto err_inval;
1247                 }
1248                 nh->nh_scope = RT_SCOPE_NOWHERE;
1249                 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1250                 err = -ENODEV;
1251                 if (!nh->nh_dev)
1252                         goto failure;
1253         } else {
1254                 int linkdown = 0;
1255
1256                 change_nexthops(fi) {
1257                         err = fib_check_nh(cfg, nexthop_nh, extack);
1258                         if (err != 0)
1259                                 goto failure;
1260                         if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1261                                 linkdown++;
1262                 } endfor_nexthops(fi)
1263                 if (linkdown == fi->fib_nhs)
1264                         fi->fib_flags |= RTNH_F_LINKDOWN;
1265         }
1266
1267         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1268                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1269                 goto err_inval;
1270         }
1271
1272         change_nexthops(fi) {
1273                 fib_info_update_nh_saddr(net, nexthop_nh);
1274         } endfor_nexthops(fi)
1275
1276         fib_rebalance(fi);
1277
1278 link_it:
1279         ofi = fib_find_info(fi);
1280         if (ofi) {
1281                 fi->fib_dead = 1;
1282                 free_fib_info(fi);
1283                 ofi->fib_treeref++;
1284                 return ofi;
1285         }
1286
1287         fi->fib_treeref++;
1288         refcount_set(&fi->fib_clntref, 1);
1289         spin_lock_bh(&fib_info_lock);
1290         hlist_add_head(&fi->fib_hash,
1291                        &fib_info_hash[fib_info_hashfn(fi)]);
1292         if (fi->fib_prefsrc) {
1293                 struct hlist_head *head;
1294
1295                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1296                 hlist_add_head(&fi->fib_lhash, head);
1297         }
1298         change_nexthops(fi) {
1299                 struct hlist_head *head;
1300                 unsigned int hash;
1301
1302                 if (!nexthop_nh->nh_dev)
1303                         continue;
1304                 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1305                 head = &fib_info_devhash[hash];
1306                 hlist_add_head(&nexthop_nh->nh_hash, head);
1307         } endfor_nexthops(fi)
1308         spin_unlock_bh(&fib_info_lock);
1309         return fi;
1310
1311 err_inval:
1312         err = -EINVAL;
1313
1314 failure:
1315         if (fi) {
1316                 fi->fib_dead = 1;
1317                 free_fib_info(fi);
1318         }
1319
1320         return ERR_PTR(err);
1321 }
1322
1323 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1324                   u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1325                   struct fib_info *fi, unsigned int flags)
1326 {
1327         struct nlmsghdr *nlh;
1328         struct rtmsg *rtm;
1329
1330         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1331         if (!nlh)
1332                 return -EMSGSIZE;
1333
1334         rtm = nlmsg_data(nlh);
1335         rtm->rtm_family = AF_INET;
1336         rtm->rtm_dst_len = dst_len;
1337         rtm->rtm_src_len = 0;
1338         rtm->rtm_tos = tos;
1339         if (tb_id < 256)
1340                 rtm->rtm_table = tb_id;
1341         else
1342                 rtm->rtm_table = RT_TABLE_COMPAT;
1343         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1344                 goto nla_put_failure;
1345         rtm->rtm_type = type;
1346         rtm->rtm_flags = fi->fib_flags;
1347         rtm->rtm_scope = fi->fib_scope;
1348         rtm->rtm_protocol = fi->fib_protocol;
1349
1350         if (rtm->rtm_dst_len &&
1351             nla_put_in_addr(skb, RTA_DST, dst))
1352                 goto nla_put_failure;
1353         if (fi->fib_priority &&
1354             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1355                 goto nla_put_failure;
1356         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1357                 goto nla_put_failure;
1358
1359         if (fi->fib_prefsrc &&
1360             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1361                 goto nla_put_failure;
1362         if (fi->fib_nhs == 1) {
1363                 if (fi->fib_nh->nh_gw &&
1364                     nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1365                         goto nla_put_failure;
1366                 if (fi->fib_nh->nh_oif &&
1367                     nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1368                         goto nla_put_failure;
1369                 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1370                         struct in_device *in_dev;
1371
1372                         rcu_read_lock();
1373                         in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1374                         if (in_dev &&
1375                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1376                                 rtm->rtm_flags |= RTNH_F_DEAD;
1377                         rcu_read_unlock();
1378                 }
1379                 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1380                         rtm->rtm_flags |= RTNH_F_OFFLOAD;
1381 #ifdef CONFIG_IP_ROUTE_CLASSID
1382                 if (fi->fib_nh[0].nh_tclassid &&
1383                     nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1384                         goto nla_put_failure;
1385 #endif
1386                 if (fi->fib_nh->nh_lwtstate &&
1387                     lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1388                         goto nla_put_failure;
1389         }
1390 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1391         if (fi->fib_nhs > 1) {
1392                 struct rtnexthop *rtnh;
1393                 struct nlattr *mp;
1394
1395                 mp = nla_nest_start(skb, RTA_MULTIPATH);
1396                 if (!mp)
1397                         goto nla_put_failure;
1398
1399                 for_nexthops(fi) {
1400                         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1401                         if (!rtnh)
1402                                 goto nla_put_failure;
1403
1404                         rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1405                         if (nh->nh_flags & RTNH_F_LINKDOWN) {
1406                                 struct in_device *in_dev;
1407
1408                                 rcu_read_lock();
1409                                 in_dev = __in_dev_get_rcu(nh->nh_dev);
1410                                 if (in_dev &&
1411                                     IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1412                                         rtnh->rtnh_flags |= RTNH_F_DEAD;
1413                                 rcu_read_unlock();
1414                         }
1415                         rtnh->rtnh_hops = nh->nh_weight - 1;
1416                         rtnh->rtnh_ifindex = nh->nh_oif;
1417
1418                         if (nh->nh_gw &&
1419                             nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1420                                 goto nla_put_failure;
1421 #ifdef CONFIG_IP_ROUTE_CLASSID
1422                         if (nh->nh_tclassid &&
1423                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1424                                 goto nla_put_failure;
1425 #endif
1426                         if (nh->nh_lwtstate &&
1427                             lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1428                                 goto nla_put_failure;
1429
1430                         /* length of rtnetlink header + attributes */
1431                         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1432                 } endfor_nexthops(fi);
1433
1434                 nla_nest_end(skb, mp);
1435         }
1436 #endif
1437         nlmsg_end(skb, nlh);
1438         return 0;
1439
1440 nla_put_failure:
1441         nlmsg_cancel(skb, nlh);
1442         return -EMSGSIZE;
1443 }
1444
1445 /*
1446  * Update FIB if:
1447  * - local address disappeared -> we must delete all the entries
1448  *   referring to it.
1449  * - device went down -> we must shutdown all nexthops going via it.
1450  */
1451 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1452 {
1453         int ret = 0;
1454         unsigned int hash = fib_laddr_hashfn(local);
1455         struct hlist_head *head = &fib_info_laddrhash[hash];
1456         struct net *net = dev_net(dev);
1457         int tb_id = l3mdev_fib_table(dev);
1458         struct fib_info *fi;
1459
1460         if (!fib_info_laddrhash || local == 0)
1461                 return 0;
1462
1463         hlist_for_each_entry(fi, head, fib_lhash) {
1464                 if (!net_eq(fi->fib_net, net) ||
1465                     fi->fib_tb_id != tb_id)
1466                         continue;
1467                 if (fi->fib_prefsrc == local) {
1468                         fi->fib_flags |= RTNH_F_DEAD;
1469                         ret++;
1470                 }
1471         }
1472         return ret;
1473 }
1474
1475 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1476                                  enum fib_event_type event_type)
1477 {
1478         struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1479         struct fib_nh_notifier_info info = {
1480                 .fib_nh = fib_nh,
1481         };
1482
1483         switch (event_type) {
1484         case FIB_EVENT_NH_ADD:
1485                 if (fib_nh->nh_flags & RTNH_F_DEAD)
1486                         break;
1487                 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1488                     fib_nh->nh_flags & RTNH_F_LINKDOWN)
1489                         break;
1490                 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1491                                            &info.info);
1492         case FIB_EVENT_NH_DEL:
1493                 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1494                      fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1495                     (fib_nh->nh_flags & RTNH_F_DEAD))
1496                         return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1497                                                    event_type, &info.info);
1498         default:
1499                 break;
1500         }
1501
1502         return NOTIFY_DONE;
1503 }
1504
1505 /* Event              force Flags           Description
1506  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1507  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1508  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1509  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1510  */
1511 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1512 {
1513         int ret = 0;
1514         int scope = RT_SCOPE_NOWHERE;
1515         struct fib_info *prev_fi = NULL;
1516         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1517         struct hlist_head *head = &fib_info_devhash[hash];
1518         struct fib_nh *nh;
1519
1520         if (force)
1521                 scope = -1;
1522
1523         hlist_for_each_entry(nh, head, nh_hash) {
1524                 struct fib_info *fi = nh->nh_parent;
1525                 int dead;
1526
1527                 BUG_ON(!fi->fib_nhs);
1528                 if (nh->nh_dev != dev || fi == prev_fi)
1529                         continue;
1530                 prev_fi = fi;
1531                 dead = 0;
1532                 change_nexthops(fi) {
1533                         if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1534                                 dead++;
1535                         else if (nexthop_nh->nh_dev == dev &&
1536                                  nexthop_nh->nh_scope != scope) {
1537                                 switch (event) {
1538                                 case NETDEV_DOWN:
1539                                 case NETDEV_UNREGISTER:
1540                                         nexthop_nh->nh_flags |= RTNH_F_DEAD;
1541                                         /* fall through */
1542                                 case NETDEV_CHANGE:
1543                                         nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1544                                         break;
1545                                 }
1546                                 call_fib_nh_notifiers(nexthop_nh,
1547                                                       FIB_EVENT_NH_DEL);
1548                                 dead++;
1549                         }
1550 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1551                         if (event == NETDEV_UNREGISTER &&
1552                             nexthop_nh->nh_dev == dev) {
1553                                 dead = fi->fib_nhs;
1554                                 break;
1555                         }
1556 #endif
1557                 } endfor_nexthops(fi)
1558                 if (dead == fi->fib_nhs) {
1559                         switch (event) {
1560                         case NETDEV_DOWN:
1561                         case NETDEV_UNREGISTER:
1562                                 fi->fib_flags |= RTNH_F_DEAD;
1563                                 /* fall through */
1564                         case NETDEV_CHANGE:
1565                                 fi->fib_flags |= RTNH_F_LINKDOWN;
1566                                 break;
1567                         }
1568                         ret++;
1569                 }
1570
1571                 fib_rebalance(fi);
1572         }
1573
1574         return ret;
1575 }
1576
1577 /* Must be invoked inside of an RCU protected region.  */
1578 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1579 {
1580         struct fib_info *fi = NULL, *last_resort = NULL;
1581         struct hlist_head *fa_head = res->fa_head;
1582         struct fib_table *tb = res->table;
1583         u8 slen = 32 - res->prefixlen;
1584         int order = -1, last_idx = -1;
1585         struct fib_alias *fa, *fa1 = NULL;
1586         u32 last_prio = res->fi->fib_priority;
1587         u8 last_tos = 0;
1588
1589         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1590                 struct fib_info *next_fi = fa->fa_info;
1591
1592                 if (fa->fa_slen != slen)
1593                         continue;
1594                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1595                         continue;
1596                 if (fa->tb_id != tb->tb_id)
1597                         continue;
1598                 if (next_fi->fib_priority > last_prio &&
1599                     fa->fa_tos == last_tos) {
1600                         if (last_tos)
1601                                 continue;
1602                         break;
1603                 }
1604                 if (next_fi->fib_flags & RTNH_F_DEAD)
1605                         continue;
1606                 last_tos = fa->fa_tos;
1607                 last_prio = next_fi->fib_priority;
1608
1609                 if (next_fi->fib_scope != res->scope ||
1610                     fa->fa_type != RTN_UNICAST)
1611                         continue;
1612                 if (!next_fi->fib_nh[0].nh_gw ||
1613                     next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1614                         continue;
1615
1616                 fib_alias_accessed(fa);
1617
1618                 if (!fi) {
1619                         if (next_fi != res->fi)
1620                                 break;
1621                         fa1 = fa;
1622                 } else if (!fib_detect_death(fi, order, &last_resort,
1623                                              &last_idx, fa1->fa_default)) {
1624                         fib_result_assign(res, fi);
1625                         fa1->fa_default = order;
1626                         goto out;
1627                 }
1628                 fi = next_fi;
1629                 order++;
1630         }
1631
1632         if (order <= 0 || !fi) {
1633                 if (fa1)
1634                         fa1->fa_default = -1;
1635                 goto out;
1636         }
1637
1638         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1639                               fa1->fa_default)) {
1640                 fib_result_assign(res, fi);
1641                 fa1->fa_default = order;
1642                 goto out;
1643         }
1644
1645         if (last_idx >= 0)
1646                 fib_result_assign(res, last_resort);
1647         fa1->fa_default = last_idx;
1648 out:
1649         return;
1650 }
1651
1652 /*
1653  * Dead device goes up. We wake up dead nexthops.
1654  * It takes sense only on multipath routes.
1655  */
1656 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1657 {
1658         struct fib_info *prev_fi;
1659         unsigned int hash;
1660         struct hlist_head *head;
1661         struct fib_nh *nh;
1662         int ret;
1663
1664         if (!(dev->flags & IFF_UP))
1665                 return 0;
1666
1667         if (nh_flags & RTNH_F_DEAD) {
1668                 unsigned int flags = dev_get_flags(dev);
1669
1670                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1671                         nh_flags |= RTNH_F_LINKDOWN;
1672         }
1673
1674         prev_fi = NULL;
1675         hash = fib_devindex_hashfn(dev->ifindex);
1676         head = &fib_info_devhash[hash];
1677         ret = 0;
1678
1679         hlist_for_each_entry(nh, head, nh_hash) {
1680                 struct fib_info *fi = nh->nh_parent;
1681                 int alive;
1682
1683                 BUG_ON(!fi->fib_nhs);
1684                 if (nh->nh_dev != dev || fi == prev_fi)
1685                         continue;
1686
1687                 prev_fi = fi;
1688                 alive = 0;
1689                 change_nexthops(fi) {
1690                         if (!(nexthop_nh->nh_flags & nh_flags)) {
1691                                 alive++;
1692                                 continue;
1693                         }
1694                         if (!nexthop_nh->nh_dev ||
1695                             !(nexthop_nh->nh_dev->flags & IFF_UP))
1696                                 continue;
1697                         if (nexthop_nh->nh_dev != dev ||
1698                             !__in_dev_get_rtnl(dev))
1699                                 continue;
1700                         alive++;
1701                         nexthop_nh->nh_flags &= ~nh_flags;
1702                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1703                 } endfor_nexthops(fi)
1704
1705                 if (alive > 0) {
1706                         fi->fib_flags &= ~nh_flags;
1707                         ret++;
1708                 }
1709
1710                 fib_rebalance(fi);
1711         }
1712
1713         return ret;
1714 }
1715
1716 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1717 static bool fib_good_nh(const struct fib_nh *nh)
1718 {
1719         int state = NUD_REACHABLE;
1720
1721         if (nh->nh_scope == RT_SCOPE_LINK) {
1722                 struct neighbour *n;
1723
1724                 rcu_read_lock_bh();
1725
1726                 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1727                                               (__force u32)nh->nh_gw);
1728                 if (n)
1729                         state = n->nud_state;
1730
1731                 rcu_read_unlock_bh();
1732         }
1733
1734         return !!(state & NUD_VALID);
1735 }
1736
1737 void fib_select_multipath(struct fib_result *res, int hash)
1738 {
1739         struct fib_info *fi = res->fi;
1740         struct net *net = fi->fib_net;
1741         bool first = false;
1742
1743         for_nexthops(fi) {
1744                 if (hash > atomic_read(&nh->nh_upper_bound))
1745                         continue;
1746
1747                 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1748                     fib_good_nh(nh)) {
1749                         res->nh_sel = nhsel;
1750                         return;
1751                 }
1752                 if (!first) {
1753                         res->nh_sel = nhsel;
1754                         first = true;
1755                 }
1756         } endfor_nexthops(fi);
1757 }
1758 #endif
1759
1760 void fib_select_path(struct net *net, struct fib_result *res,
1761                      struct flowi4 *fl4, const struct sk_buff *skb)
1762 {
1763         bool oif_check;
1764
1765         oif_check = (fl4->flowi4_oif == 0 ||
1766                      fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1767
1768 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1769         if (res->fi->fib_nhs > 1 && oif_check) {
1770                 int h = fib_multipath_hash(res->fi, fl4, skb);
1771
1772                 fib_select_multipath(res, h);
1773         }
1774         else
1775 #endif
1776         if (!res->prefixlen &&
1777             res->table->tb_num_default > 1 &&
1778             res->type == RTN_UNICAST && oif_check)
1779                 fib_select_default(fl4, res);
1780
1781         if (!fl4->saddr)
1782                 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1783 }
1784 EXPORT_SYMBOL_GPL(fib_select_path);