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, <kuznet@ms2.inr.ac.ru>
   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 #ifdef CONFIG_IP_ROUTE_CLASSID
 650                 if (cfg->fc_flow &&
 651                     cfg->fc_flow != fi->fib_nh->nh_tclassid)
 652                         return 1;
 653 #endif
 654                 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
 655                     (!cfg->fc_gw  || cfg->fc_gw == fi->fib_nh->nh_gw))
 656                         return 0;
 657                 return 1;
 658         }
 659
 660 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 661         if (!cfg->fc_mp)
 662                 return 0;
 663
 664         rtnh = cfg->fc_mp;
 665         remaining = cfg->fc_mp_len;
 666
 667         for_nexthops(fi) {
 668                 int attrlen;
 669
 670                 if (!rtnh_ok(rtnh, remaining))
 671                         return -EINVAL;
 672
 673                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
 674                         return 1;
 675
 676                 attrlen = rtnh_attrlen(rtnh);
 677                 if (attrlen > 0) {
 678                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
 679
 680                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 681                         if (nla && nla_get_in_addr(nla) != nh->nh_gw)
 682                                 return 1;
 683 #ifdef CONFIG_IP_ROUTE_CLASSID
 684                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 685                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 686                                 return 1;
 687 #endif
 688                 }
 689
 690                 rtnh = rtnh_next(rtnh, &remaining);
 691         } endfor_nexthops(fi);
 692 #endif
 693         return 0;
 694 }
 695
 696 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 697 {
 698         struct nlattr *nla;
 699         int remaining;
 700
 701         if (!cfg->fc_mx)
 702                 return true;
 703
 704         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 705                 int type = nla_type(nla);
 706                 u32 fi_val, val;
 707
 708                 if (!type)
 709                         continue;
 710                 if (type > RTAX_MAX)
 711                         return false;
 712
 713                 if (type == RTAX_CC_ALGO) {
 714                         char tmp[TCP_CA_NAME_MAX];
 715                         bool ecn_ca = false;
 716
 717                         nla_strlcpy(tmp, nla, sizeof(tmp));
 718                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 719                 } else {
 720                         val = nla_get_u32(nla);
 721                 }
 722
 723                 fi_val = fi->fib_metrics->metrics[type - 1];
 724                 if (type == RTAX_FEATURES)
 725                         fi_val &= ~DST_FEATURE_ECN_CA;
 726
 727                 if (fi_val != val)
 728                         return false;
 729         }
 730
 731         return true;
 732 }
 733
 734
 735 /*
 736  * Picture
 737  * -------
 738  *
 739  * Semantics of nexthop is very messy by historical reasons.
 740  * We have to take into account, that:
 741  * a) gateway can be actually local interface address,
 742  *    so that gatewayed route is direct.
 743  * b) gateway must be on-link address, possibly
 744  *    described not by an ifaddr, but also by a direct route.
 745  * c) If both gateway and interface are specified, they should not
 746  *    contradict.
 747  * d) If we use tunnel routes, gateway could be not on-link.
 748  *
 749  * Attempt to reconcile all of these (alas, self-contradictory) conditions
 750  * results in pretty ugly and hairy code with obscure logic.
 751  *
 752  * I chose to generalized it instead, so that the size
 753  * of code does not increase practically, but it becomes
 754  * much more general.
 755  * Every prefix is assigned a "scope" value: "host" is local address,
 756  * "link" is direct route,
 757  * [ ... "site" ... "interior" ... ]
 758  * and "universe" is true gateway route with global meaning.
 759  *
 760  * Every prefix refers to a set of "nexthop"s (gw, oif),
 761  * where gw must have narrower scope. This recursion stops
 762  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
 763  * which means that gw is forced to be on link.
 764  *
 765  * Code is still hairy, but now it is apparently logically
 766  * consistent and very flexible. F.e. as by-product it allows
 767  * to co-exists in peace independent exterior and interior
 768  * routing processes.
 769  *
 770  * Normally it looks as following.
 771  *
 772  * {universe prefix}  -> (gw, oif) [scope link]
 773  *                |
 774  *                |-> {link prefix} -> (gw, oif) [scope local]
 775  *                                      |
 776  *                                      |-> {local prefix} (terminal node)
 777  */
 778 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
 779                         struct netlink_ext_ack *extack)
 780 {
 781         int err = 0;
 782         struct net *net;
 783         struct net_device *dev;
 784
 785         net = cfg->fc_nlinfo.nl_net;
 786         if (nh->nh_gw) {
 787                 struct fib_result res;
 788
 789                 if (nh->nh_flags & RTNH_F_ONLINK) {
 790                         unsigned int addr_type;
 791
 792                         if (cfg->fc_scope >= RT_SCOPE_LINK) {
 793                                 NL_SET_ERR_MSG(extack,
 794                                                "Nexthop has invalid scope");
 795                                 return -EINVAL;
 796                         }
 797                         dev = __dev_get_by_index(net, nh->nh_oif);
 798                         if (!dev)
 799                                 return -ENODEV;
 800                         if (!(dev->flags & IFF_UP)) {
 801                                 NL_SET_ERR_MSG(extack,
 802                                                "Nexthop device is not up");
 803                                 return -ENETDOWN;
 804                         }
 805                         addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
 806                         if (addr_type != RTN_UNICAST) {
 807                                 NL_SET_ERR_MSG(extack,
 808                                                "Nexthop has invalid gateway");
 809                                 return -EINVAL;
 810                         }
 811                         if (!netif_carrier_ok(dev))
 812                                 nh->nh_flags |= RTNH_F_LINKDOWN;
 813                         nh->nh_dev = dev;
 814                         dev_hold(dev);
 815                         nh->nh_scope = RT_SCOPE_LINK;
 816                         return 0;
 817                 }
 818                 rcu_read_lock();
 819                 {
 820                         struct fib_table *tbl = NULL;
 821                         struct flowi4 fl4 = {
 822                                 .daddr = nh->nh_gw,
 823                                 .flowi4_scope = cfg->fc_scope + 1,
 824                                 .flowi4_oif = nh->nh_oif,
 825                                 .flowi4_iif = LOOPBACK_IFINDEX,
 826                         };
 827
 828                         /* It is not necessary, but requires a bit of thinking */
 829                         if (fl4.flowi4_scope < RT_SCOPE_LINK)
 830                                 fl4.flowi4_scope = RT_SCOPE_LINK;
 831
 832                         if (cfg->fc_table)
 833                                 tbl = fib_get_table(net, cfg->fc_table);
 834
 835                         if (tbl)
 836                                 err = fib_table_lookup(tbl, &fl4, &res,
 837                                                        FIB_LOOKUP_IGNORE_LINKSTATE |
 838                                                        FIB_LOOKUP_NOREF);
 839
 840                         /* on error or if no table given do full lookup. This
 841                          * is needed for example when nexthops are in the local
 842                          * table rather than the given table
 843                          */
 844                         if (!tbl || err) {
 845                                 err = fib_lookup(net, &fl4, &res,
 846                                                  FIB_LOOKUP_IGNORE_LINKSTATE);
 847                         }
 848
 849                         if (err) {
 850                                 NL_SET_ERR_MSG(extack,
 851                                                "Nexthop has invalid gateway");
 852                                 rcu_read_unlock();
 853                                 return err;
 854                         }
 855                 }
 856                 err = -EINVAL;
 857                 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
 858                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
 859                         goto out;
 860                 }
 861                 nh->nh_scope = res.scope;
 862                 nh->nh_oif = FIB_RES_OIF(res);
 863                 nh->nh_dev = dev = FIB_RES_DEV(res);
 864                 if (!dev) {
 865                         NL_SET_ERR_MSG(extack,
 866                                        "No egress device for nexthop gateway");
 867                         goto out;
 868                 }
 869                 dev_hold(dev);
 870                 if (!netif_carrier_ok(dev))
 871                         nh->nh_flags |= RTNH_F_LINKDOWN;
 872                 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
 873         } else {
 874                 struct in_device *in_dev;
 875
 876                 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
 877                         NL_SET_ERR_MSG(extack,
 878                                        "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
 879                         return -EINVAL;
 880                 }
 881                 rcu_read_lock();
 882                 err = -ENODEV;
 883                 in_dev = inetdev_by_index(net, nh->nh_oif);
 884                 if (!in_dev)
 885                         goto out;
 886                 err = -ENETDOWN;
 887                 if (!(in_dev->dev->flags & IFF_UP)) {
 888                         NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
 889                         goto out;
 890                 }
 891                 nh->nh_dev = in_dev->dev;
 892                 dev_hold(nh->nh_dev);
 893                 nh->nh_scope = RT_SCOPE_HOST;
 894                 if (!netif_carrier_ok(nh->nh_dev))
 895                         nh->nh_flags |= RTNH_F_LINKDOWN;
 896                 err = 0;
 897         }
 898 out:
 899         rcu_read_unlock();
 900         return err;
 901 }
 902
 903 static inline unsigned int fib_laddr_hashfn(__be32 val)
 904 {
 905         unsigned int mask = (fib_info_hash_size - 1);
 906
 907         return ((__force u32)val ^
 908                 ((__force u32)val >> 7) ^
 909                 ((__force u32)val >> 14)) & mask;
 910 }
 911
 912 static struct hlist_head *fib_info_hash_alloc(int bytes)
 913 {
 914         if (bytes <= PAGE_SIZE)
 915                 return kzalloc(bytes, GFP_KERNEL);
 916         else
 917                 return (struct hlist_head *)
 918                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
 919                                          get_order(bytes));
 920 }
 921
 922 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
 923 {
 924         if (!hash)
 925                 return;
 926
 927         if (bytes <= PAGE_SIZE)
 928                 kfree(hash);
 929         else
 930                 free_pages((unsigned long) hash, get_order(bytes));
 931 }
 932
 933 static void fib_info_hash_move(struct hlist_head *new_info_hash,
 934                                struct hlist_head *new_laddrhash,
 935                                unsigned int new_size)
 936 {
 937         struct hlist_head *old_info_hash, *old_laddrhash;
 938         unsigned int old_size = fib_info_hash_size;
 939         unsigned int i, bytes;
 940
 941         spin_lock_bh(&fib_info_lock);
 942         old_info_hash = fib_info_hash;
 943         old_laddrhash = fib_info_laddrhash;
 944         fib_info_hash_size = new_size;
 945
 946         for (i = 0; i < old_size; i++) {
 947                 struct hlist_head *head = &fib_info_hash[i];
 948                 struct hlist_node *n;
 949                 struct fib_info *fi;
 950
 951                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
 952                         struct hlist_head *dest;
 953                         unsigned int new_hash;
 954
 955                         new_hash = fib_info_hashfn(fi);
 956                         dest = &new_info_hash[new_hash];
 957                         hlist_add_head(&fi->fib_hash, dest);
 958                 }
 959         }
 960         fib_info_hash = new_info_hash;
 961
 962         for (i = 0; i < old_size; i++) {
 963                 struct hlist_head *lhead = &fib_info_laddrhash[i];
 964                 struct hlist_node *n;
 965                 struct fib_info *fi;
 966
 967                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
 968                         struct hlist_head *ldest;
 969                         unsigned int new_hash;
 970
 971                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
 972                         ldest = &new_laddrhash[new_hash];
 973                         hlist_add_head(&fi->fib_lhash, ldest);
 974                 }
 975         }
 976         fib_info_laddrhash = new_laddrhash;
 977
 978         spin_unlock_bh(&fib_info_lock);
 979
 980         bytes = old_size * sizeof(struct hlist_head *);
 981         fib_info_hash_free(old_info_hash, bytes);
 982         fib_info_hash_free(old_laddrhash, bytes);
 983 }
 984
 985 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
 986 {
 987         nh->nh_saddr = inet_select_addr(nh->nh_dev,
 988                                         nh->nh_gw,
 989                                         nh->nh_parent->fib_scope);
 990         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
 991
 992         return nh->nh_saddr;
 993 }
 994
 995 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
 996 {
 997         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
 998             fib_prefsrc != cfg->fc_dst) {
 999                 u32 tb_id = cfg->fc_table;
1000                 int rc;
1001
1002                 if (tb_id == RT_TABLE_MAIN)
1003                         tb_id = RT_TABLE_LOCAL;
1004
1005                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1006                                           fib_prefsrc, tb_id);
1007
1008                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1009                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1010                                                   fib_prefsrc, RT_TABLE_LOCAL);
1011                 }
1012
1013                 if (rc != RTN_LOCAL)
1014                         return false;
1015         }
1016         return true;
1017 }
1018
1019 static int
1020 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
1021 {
1022         bool ecn_ca = false;
1023         struct nlattr *nla;
1024         int remaining;
1025
1026         if (!cfg->fc_mx)
1027                 return 0;
1028
1029         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1030                 int type = nla_type(nla);
1031                 u32 val;
1032
1033                 if (!type)
1034                         continue;
1035                 if (type > RTAX_MAX)
1036                         return -EINVAL;
1037
1038                 if (type == RTAX_CC_ALGO) {
1039                         char tmp[TCP_CA_NAME_MAX];
1040
1041                         nla_strlcpy(tmp, nla, sizeof(tmp));
1042                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1043                         if (val == TCP_CA_UNSPEC)
1044                                 return -EINVAL;
1045                 } else {
1046                         val = nla_get_u32(nla);
1047                 }
1048                 if (type == RTAX_ADVMSS && val > 65535 - 40)
1049                         val = 65535 - 40;
1050                 if (type == RTAX_MTU && val > 65535 - 15)
1051                         val = 65535 - 15;
1052                 if (type == RTAX_HOPLIMIT && val > 255)
1053                         val = 255;
1054                 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1055                         return -EINVAL;
1056                 fi->fib_metrics->metrics[type - 1] = val;
1057         }
1058
1059         if (ecn_ca)
1060                 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1061
1062         return 0;
1063 }
1064
1065 struct fib_info *fib_create_info(struct fib_config *cfg,
1066                                  struct netlink_ext_ack *extack)
1067 {
1068         int err;
1069         struct fib_info *fi = NULL;
1070         struct fib_info *ofi;
1071         int nhs = 1;
1072         struct net *net = cfg->fc_nlinfo.nl_net;
1073
1074         if (cfg->fc_type > RTN_MAX)
1075                 goto err_inval;
1076
1077         /* Fast check to catch the most weird cases */
1078         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1079                 NL_SET_ERR_MSG(extack, "Invalid scope");
1080                 goto err_inval;
1081         }
1082
1083         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1084                 NL_SET_ERR_MSG(extack,
1085                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1086                 goto err_inval;
1087         }
1088
1089 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1090         if (cfg->fc_mp) {
1091                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1092                 if (nhs == 0)
1093                         goto err_inval;
1094         }
1095 #endif
1096
1097         err = -ENOBUFS;
1098         if (fib_info_cnt >= fib_info_hash_size) {
1099                 unsigned int new_size = fib_info_hash_size << 1;
1100                 struct hlist_head *new_info_hash;
1101                 struct hlist_head *new_laddrhash;
1102                 unsigned int bytes;
1103
1104                 if (!new_size)
1105                         new_size = 16;
1106                 bytes = new_size * sizeof(struct hlist_head *);
1107                 new_info_hash = fib_info_hash_alloc(bytes);
1108                 new_laddrhash = fib_info_hash_alloc(bytes);
1109                 if (!new_info_hash || !new_laddrhash) {
1110                         fib_info_hash_free(new_info_hash, bytes);
1111                         fib_info_hash_free(new_laddrhash, bytes);
1112                 } else
1113                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1114
1115                 if (!fib_info_hash_size)
1116                         goto failure;
1117         }
1118
1119         fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1120         if (!fi)
1121                 goto failure;
1122         if (cfg->fc_mx) {
1123                 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1124                 if (unlikely(!fi->fib_metrics)) {
1125                         kfree(fi);
1126                         return ERR_PTR(err);
1127                 }
1128                 refcount_set(&fi->fib_metrics->refcnt, 1);
1129         } else {
1130                 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1131         }
1132         fib_info_cnt++;
1133         fi->fib_net = net;
1134         fi->fib_protocol = cfg->fc_protocol;
1135         fi->fib_scope = cfg->fc_scope;
1136         fi->fib_flags = cfg->fc_flags;
1137         fi->fib_priority = cfg->fc_priority;
1138         fi->fib_prefsrc = cfg->fc_prefsrc;
1139         fi->fib_type = cfg->fc_type;
1140         fi->fib_tb_id = cfg->fc_table;
1141
1142         fi->fib_nhs = nhs;
1143         change_nexthops(fi) {
1144                 nexthop_nh->nh_parent = fi;
1145                 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1146                 if (!nexthop_nh->nh_pcpu_rth_output)
1147                         goto failure;
1148         } endfor_nexthops(fi)
1149
1150         err = fib_convert_metrics(fi, cfg);
1151         if (err)
1152                 goto failure;
1153
1154         if (cfg->fc_mp) {
1155 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1156                 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1157                 if (err != 0)
1158                         goto failure;
1159                 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1160                         NL_SET_ERR_MSG(extack,
1161                                        "Nexthop device index does not match RTA_OIF");
1162                         goto err_inval;
1163                 }
1164                 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1165                         NL_SET_ERR_MSG(extack,
1166                                        "Nexthop gateway does not match RTA_GATEWAY");
1167                         goto err_inval;
1168                 }
1169 #ifdef CONFIG_IP_ROUTE_CLASSID
1170                 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1171                         NL_SET_ERR_MSG(extack,
1172                                        "Nexthop class id does not match RTA_FLOW");
1173                         goto err_inval;
1174                 }
1175 #endif
1176 #else
1177                 NL_SET_ERR_MSG(extack,
1178                                "Multipath support not enabled in kernel");
1179                 goto err_inval;
1180 #endif
1181         } else {
1182                 struct fib_nh *nh = fi->fib_nh;
1183
1184                 if (cfg->fc_encap) {
1185                         struct lwtunnel_state *lwtstate;
1186
1187                         if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1188                                 NL_SET_ERR_MSG(extack,
1189                                                "LWT encap type not specified");
1190                                 goto err_inval;
1191                         }
1192                         err = lwtunnel_build_state(cfg->fc_encap_type,
1193                                                    cfg->fc_encap, AF_INET, cfg,
1194                                                    &lwtstate, extack);
1195                         if (err)
1196                                 goto failure;
1197
1198                         nh->nh_lwtstate = lwtstate_get(lwtstate);
1199                 }
1200                 nh->nh_oif = cfg->fc_oif;
1201                 nh->nh_gw = cfg->fc_gw;
1202                 nh->nh_flags = cfg->fc_flags;
1203 #ifdef CONFIG_IP_ROUTE_CLASSID
1204                 nh->nh_tclassid = cfg->fc_flow;
1205                 if (nh->nh_tclassid)
1206                         fi->fib_net->ipv4.fib_num_tclassid_users++;
1207 #endif
1208 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1209                 nh->nh_weight = 1;
1210 #endif
1211         }
1212
1213         if (fib_props[cfg->fc_type].error) {
1214                 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1215                         NL_SET_ERR_MSG(extack,
1216                                        "Gateway, device and multipath can not be specified for this route type");
1217                         goto err_inval;
1218                 }
1219                 goto link_it;
1220         } else {
1221                 switch (cfg->fc_type) {
1222                 case RTN_UNICAST:
1223                 case RTN_LOCAL:
1224                 case RTN_BROADCAST:
1225                 case RTN_ANYCAST:
1226                 case RTN_MULTICAST:
1227                         break;
1228                 default:
1229                         NL_SET_ERR_MSG(extack, "Invalid route type");
1230                         goto err_inval;
1231                 }
1232         }
1233
1234         if (cfg->fc_scope > RT_SCOPE_HOST) {
1235                 NL_SET_ERR_MSG(extack, "Invalid scope");
1236                 goto err_inval;
1237         }
1238
1239         if (cfg->fc_scope == RT_SCOPE_HOST) {
1240                 struct fib_nh *nh = fi->fib_nh;
1241
1242                 /* Local address is added. */
1243                 if (nhs != 1) {
1244                         NL_SET_ERR_MSG(extack,
1245                                        "Route with host scope can not have multiple nexthops");
1246                         goto err_inval;
1247                 }
1248                 if (nh->nh_gw) {
1249                         NL_SET_ERR_MSG(extack,
1250                                        "Route with host scope can not have a gateway");
1251                         goto err_inval;
1252                 }
1253                 nh->nh_scope = RT_SCOPE_NOWHERE;
1254                 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1255                 err = -ENODEV;
1256                 if (!nh->nh_dev)
1257                         goto failure;
1258         } else {
1259                 int linkdown = 0;
1260
1261                 change_nexthops(fi) {
1262                         err = fib_check_nh(cfg, nexthop_nh, extack);
1263                         if (err != 0)
1264                                 goto failure;
1265                         if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1266                                 linkdown++;
1267                 } endfor_nexthops(fi)
1268                 if (linkdown == fi->fib_nhs)
1269                         fi->fib_flags |= RTNH_F_LINKDOWN;
1270         }
1271
1272         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1273                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1274                 goto err_inval;
1275         }
1276
1277         change_nexthops(fi) {
1278                 fib_info_update_nh_saddr(net, nexthop_nh);
1279         } endfor_nexthops(fi)
1280
1281         fib_rebalance(fi);
1282
1283 link_it:
1284         ofi = fib_find_info(fi);
1285         if (ofi) {
1286                 fi->fib_dead = 1;
1287                 free_fib_info(fi);
1288                 ofi->fib_treeref++;
1289                 return ofi;
1290         }
1291
1292         fi->fib_treeref++;
1293         refcount_set(&fi->fib_clntref, 1);
1294         spin_lock_bh(&fib_info_lock);
1295         hlist_add_head(&fi->fib_hash,
1296                        &fib_info_hash[fib_info_hashfn(fi)]);
1297         if (fi->fib_prefsrc) {
1298                 struct hlist_head *head;
1299
1300                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1301                 hlist_add_head(&fi->fib_lhash, head);
1302         }
1303         change_nexthops(fi) {
1304                 struct hlist_head *head;
1305                 unsigned int hash;
1306
1307                 if (!nexthop_nh->nh_dev)
1308                         continue;
1309                 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1310                 head = &fib_info_devhash[hash];
1311                 hlist_add_head(&nexthop_nh->nh_hash, head);
1312         } endfor_nexthops(fi)
1313         spin_unlock_bh(&fib_info_lock);
1314         return fi;
1315
1316 err_inval:
1317         err = -EINVAL;
1318
1319 failure:
1320         if (fi) {
1321                 fi->fib_dead = 1;
1322                 free_fib_info(fi);
1323         }
1324
1325         return ERR_PTR(err);
1326 }
1327
1328 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1329                   u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1330                   struct fib_info *fi, unsigned int flags)
1331 {
1332         struct nlmsghdr *nlh;
1333         struct rtmsg *rtm;
1334
1335         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1336         if (!nlh)
1337                 return -EMSGSIZE;
1338
1339         rtm = nlmsg_data(nlh);
1340         rtm->rtm_family = AF_INET;
1341         rtm->rtm_dst_len = dst_len;
1342         rtm->rtm_src_len = 0;
1343         rtm->rtm_tos = tos;
1344         if (tb_id < 256)
1345                 rtm->rtm_table = tb_id;
1346         else
1347                 rtm->rtm_table = RT_TABLE_COMPAT;
1348         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1349                 goto nla_put_failure;
1350         rtm->rtm_type = type;
1351         rtm->rtm_flags = fi->fib_flags;
1352         rtm->rtm_scope = fi->fib_scope;
1353         rtm->rtm_protocol = fi->fib_protocol;
1354
1355         if (rtm->rtm_dst_len &&
1356             nla_put_in_addr(skb, RTA_DST, dst))
1357                 goto nla_put_failure;
1358         if (fi->fib_priority &&
1359             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1360                 goto nla_put_failure;
1361         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1362                 goto nla_put_failure;
1363
1364         if (fi->fib_prefsrc &&
1365             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1366                 goto nla_put_failure;
1367         if (fi->fib_nhs == 1) {
1368                 if (fi->fib_nh->nh_gw &&
1369                     nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1370                         goto nla_put_failure;
1371                 if (fi->fib_nh->nh_oif &&
1372                     nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1373                         goto nla_put_failure;
1374                 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1375                         struct in_device *in_dev;
1376
1377                         rcu_read_lock();
1378                         in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1379                         if (in_dev &&
1380                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1381                                 rtm->rtm_flags |= RTNH_F_DEAD;
1382                         rcu_read_unlock();
1383                 }
1384                 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1385                         rtm->rtm_flags |= RTNH_F_OFFLOAD;
1386 #ifdef CONFIG_IP_ROUTE_CLASSID
1387                 if (fi->fib_nh[0].nh_tclassid &&
1388                     nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1389                         goto nla_put_failure;
1390 #endif
1391                 if (fi->fib_nh->nh_lwtstate &&
1392                     lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1393                         goto nla_put_failure;
1394         }
1395 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1396         if (fi->fib_nhs > 1) {
1397                 struct rtnexthop *rtnh;
1398                 struct nlattr *mp;
1399
1400                 mp = nla_nest_start(skb, RTA_MULTIPATH);
1401                 if (!mp)
1402                         goto nla_put_failure;
1403
1404                 for_nexthops(fi) {
1405                         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1406                         if (!rtnh)
1407                                 goto nla_put_failure;
1408
1409                         rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1410                         if (nh->nh_flags & RTNH_F_LINKDOWN) {
1411                                 struct in_device *in_dev;
1412
1413                                 rcu_read_lock();
1414                                 in_dev = __in_dev_get_rcu(nh->nh_dev);
1415                                 if (in_dev &&
1416                                     IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1417                                         rtnh->rtnh_flags |= RTNH_F_DEAD;
1418                                 rcu_read_unlock();
1419                         }
1420                         rtnh->rtnh_hops = nh->nh_weight - 1;
1421                         rtnh->rtnh_ifindex = nh->nh_oif;
1422
1423                         if (nh->nh_gw &&
1424                             nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1425                                 goto nla_put_failure;
1426 #ifdef CONFIG_IP_ROUTE_CLASSID
1427                         if (nh->nh_tclassid &&
1428                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1429                                 goto nla_put_failure;
1430 #endif
1431                         if (nh->nh_lwtstate &&
1432                             lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1433                                 goto nla_put_failure;
1434
1435                         /* length of rtnetlink header + attributes */
1436                         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1437                 } endfor_nexthops(fi);
1438
1439                 nla_nest_end(skb, mp);
1440         }
1441 #endif
1442         nlmsg_end(skb, nlh);
1443         return 0;
1444
1445 nla_put_failure:
1446         nlmsg_cancel(skb, nlh);
1447         return -EMSGSIZE;
1448 }
1449
1450 /*
1451  * Update FIB if:
1452  * - local address disappeared -> we must delete all the entries
1453  *   referring to it.
1454  * - device went down -> we must shutdown all nexthops going via it.
1455  */
1456 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1457 {
1458         int ret = 0;
1459         unsigned int hash = fib_laddr_hashfn(local);
1460         struct hlist_head *head = &fib_info_laddrhash[hash];
1461         struct net *net = dev_net(dev);
1462         int tb_id = l3mdev_fib_table(dev);
1463         struct fib_info *fi;
1464
1465         if (!fib_info_laddrhash || local == 0)
1466                 return 0;
1467
1468         hlist_for_each_entry(fi, head, fib_lhash) {
1469                 if (!net_eq(fi->fib_net, net) ||
1470                     fi->fib_tb_id != tb_id)
1471                         continue;
1472                 if (fi->fib_prefsrc == local) {
1473                         fi->fib_flags |= RTNH_F_DEAD;
1474                         ret++;
1475                 }
1476         }
1477         return ret;
1478 }
1479
1480 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1481                                  enum fib_event_type event_type)
1482 {
1483         struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1484         struct fib_nh_notifier_info info = {
1485                 .fib_nh = fib_nh,
1486         };
1487
1488         switch (event_type) {
1489         case FIB_EVENT_NH_ADD:
1490                 if (fib_nh->nh_flags & RTNH_F_DEAD)
1491                         break;
1492                 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1493                     fib_nh->nh_flags & RTNH_F_LINKDOWN)
1494                         break;
1495                 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1496                                            &info.info);
1497         case FIB_EVENT_NH_DEL:
1498                 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1499                      fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1500                     (fib_nh->nh_flags & RTNH_F_DEAD))
1501                         return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1502                                                    event_type, &info.info);
1503         default:
1504                 break;
1505         }
1506
1507         return NOTIFY_DONE;
1508 }
1509
1510 /* Event              force Flags           Description
1511  * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1512  * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1513  * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1514  * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1515  */
1516 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1517 {
1518         int ret = 0;
1519         int scope = RT_SCOPE_NOWHERE;
1520         struct fib_info *prev_fi = NULL;
1521         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1522         struct hlist_head *head = &fib_info_devhash[hash];
1523         struct fib_nh *nh;
1524
1525         if (force)
1526                 scope = -1;
1527
1528         hlist_for_each_entry(nh, head, nh_hash) {
1529                 struct fib_info *fi = nh->nh_parent;
1530                 int dead;
1531
1532                 BUG_ON(!fi->fib_nhs);
1533                 if (nh->nh_dev != dev || fi == prev_fi)
1534                         continue;
1535                 prev_fi = fi;
1536                 dead = 0;
1537                 change_nexthops(fi) {
1538                         if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1539                                 dead++;
1540                         else if (nexthop_nh->nh_dev == dev &&
1541                                  nexthop_nh->nh_scope != scope) {
1542                                 switch (event) {
1543                                 case NETDEV_DOWN:
1544                                 case NETDEV_UNREGISTER:
1545                                         nexthop_nh->nh_flags |= RTNH_F_DEAD;
1546                                         /* fall through */
1547                                 case NETDEV_CHANGE:
1548                                         nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1549                                         break;
1550                                 }
1551                                 call_fib_nh_notifiers(nexthop_nh,
1552                                                       FIB_EVENT_NH_DEL);
1553                                 dead++;
1554                         }
1555 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1556                         if (event == NETDEV_UNREGISTER &&
1557                             nexthop_nh->nh_dev == dev) {
1558                                 dead = fi->fib_nhs;
1559                                 break;
1560                         }
1561 #endif
1562                 } endfor_nexthops(fi)
1563                 if (dead == fi->fib_nhs) {
1564                         switch (event) {
1565                         case NETDEV_DOWN:
1566                         case NETDEV_UNREGISTER:
1567                                 fi->fib_flags |= RTNH_F_DEAD;
1568                                 /* fall through */
1569                         case NETDEV_CHANGE:
1570                                 fi->fib_flags |= RTNH_F_LINKDOWN;
1571                                 break;
1572                         }
1573                         ret++;
1574                 }
1575
1576                 fib_rebalance(fi);
1577         }
1578
1579         return ret;
1580 }
1581
1582 /* Must be invoked inside of an RCU protected region.  */
1583 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1584 {
1585         struct fib_info *fi = NULL, *last_resort = NULL;
1586         struct hlist_head *fa_head = res->fa_head;
1587         struct fib_table *tb = res->table;
1588         u8 slen = 32 - res->prefixlen;
1589         int order = -1, last_idx = -1;
1590         struct fib_alias *fa, *fa1 = NULL;
1591         u32 last_prio = res->fi->fib_priority;
1592         u8 last_tos = 0;
1593
1594         hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1595                 struct fib_info *next_fi = fa->fa_info;
1596
1597                 if (fa->fa_slen != slen)
1598                         continue;
1599                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1600                         continue;
1601                 if (fa->tb_id != tb->tb_id)
1602                         continue;
1603                 if (next_fi->fib_priority > last_prio &&
1604                     fa->fa_tos == last_tos) {
1605                         if (last_tos)
1606                                 continue;
1607                         break;
1608                 }
1609                 if (next_fi->fib_flags & RTNH_F_DEAD)
1610                         continue;
1611                 last_tos = fa->fa_tos;
1612                 last_prio = next_fi->fib_priority;
1613
1614                 if (next_fi->fib_scope != res->scope ||
1615                     fa->fa_type != RTN_UNICAST)
1616                         continue;
1617                 if (!next_fi->fib_nh[0].nh_gw ||
1618                     next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1619                         continue;
1620
1621                 fib_alias_accessed(fa);
1622
1623                 if (!fi) {
1624                         if (next_fi != res->fi)
1625                                 break;
1626                         fa1 = fa;
1627                 } else if (!fib_detect_death(fi, order, &last_resort,
1628                                              &last_idx, fa1->fa_default)) {
1629                         fib_result_assign(res, fi);
1630                         fa1->fa_default = order;
1631                         goto out;
1632                 }
1633                 fi = next_fi;
1634                 order++;
1635         }
1636
1637         if (order <= 0 || !fi) {
1638                 if (fa1)
1639                         fa1->fa_default = -1;
1640                 goto out;
1641         }
1642
1643         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1644                               fa1->fa_default)) {
1645                 fib_result_assign(res, fi);
1646                 fa1->fa_default = order;
1647                 goto out;
1648         }
1649
1650         if (last_idx >= 0)
1651                 fib_result_assign(res, last_resort);
1652         fa1->fa_default = last_idx;
1653 out:
1654         return;
1655 }
1656
1657 /*
1658  * Dead device goes up. We wake up dead nexthops.
1659  * It takes sense only on multipath routes.
1660  */
1661 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1662 {
1663         struct fib_info *prev_fi;
1664         unsigned int hash;
1665         struct hlist_head *head;
1666         struct fib_nh *nh;
1667         int ret;
1668
1669         if (!(dev->flags & IFF_UP))
1670                 return 0;
1671
1672         if (nh_flags & RTNH_F_DEAD) {
1673                 unsigned int flags = dev_get_flags(dev);
1674
1675                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1676                         nh_flags |= RTNH_F_LINKDOWN;
1677         }
1678
1679         prev_fi = NULL;
1680         hash = fib_devindex_hashfn(dev->ifindex);
1681         head = &fib_info_devhash[hash];
1682         ret = 0;
1683
1684         hlist_for_each_entry(nh, head, nh_hash) {
1685                 struct fib_info *fi = nh->nh_parent;
1686                 int alive;
1687
1688                 BUG_ON(!fi->fib_nhs);
1689                 if (nh->nh_dev != dev || fi == prev_fi)
1690                         continue;
1691
1692                 prev_fi = fi;
1693                 alive = 0;
1694                 change_nexthops(fi) {
1695                         if (!(nexthop_nh->nh_flags & nh_flags)) {
1696                                 alive++;
1697                                 continue;
1698                         }
1699                         if (!nexthop_nh->nh_dev ||
1700                             !(nexthop_nh->nh_dev->flags & IFF_UP))
1701                                 continue;
1702                         if (nexthop_nh->nh_dev != dev ||
1703                             !__in_dev_get_rtnl(dev))
1704                                 continue;
1705                         alive++;
1706                         nexthop_nh->nh_flags &= ~nh_flags;
1707                         call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1708                 } endfor_nexthops(fi)
1709
1710                 if (alive > 0) {
1711                         fi->fib_flags &= ~nh_flags;
1712                         ret++;
1713                 }
1714
1715                 fib_rebalance(fi);
1716         }
1717
1718         return ret;
1719 }
1720
1721 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1722 static bool fib_good_nh(const struct fib_nh *nh)
1723 {
1724         int state = NUD_REACHABLE;
1725
1726         if (nh->nh_scope == RT_SCOPE_LINK) {
1727                 struct neighbour *n;
1728
1729                 rcu_read_lock_bh();
1730
1731                 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1732                                               (__force u32)nh->nh_gw);
1733                 if (n)
1734                         state = n->nud_state;
1735
1736                 rcu_read_unlock_bh();
1737         }
1738
1739         return !!(state & NUD_VALID);
1740 }
1741
1742 void fib_select_multipath(struct fib_result *res, int hash)
1743 {
1744         struct fib_info *fi = res->fi;
1745         struct net *net = fi->fib_net;
1746         bool first = false;
1747
1748         for_nexthops(fi) {
1749                 if (hash > atomic_read(&nh->nh_upper_bound))
1750                         continue;
1751
1752                 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1753                     fib_good_nh(nh)) {
1754                         res->nh_sel = nhsel;
1755                         return;
1756                 }
1757                 if (!first) {
1758                         res->nh_sel = nhsel;
1759                         first = true;
1760                 }
1761         } endfor_nexthops(fi);
1762 }
1763 #endif
1764
1765 void fib_select_path(struct net *net, struct fib_result *res,
1766                      struct flowi4 *fl4, const struct sk_buff *skb)
1767 {
1768         bool oif_check;
1769
1770         oif_check = (fl4->flowi4_oif == 0 ||
1771                      fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1772
1773 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1774         if (res->fi->fib_nhs > 1 && oif_check) {
1775                 int h = fib_multipath_hash(res->fi, fl4, skb);
1776
1777                 fib_select_multipath(res, h);
1778         }
1779         else
1780 #endif
1781         if (!res->prefixlen &&
1782             res->table->tb_num_default > 1 &&
1783             res->type == RTN_UNICAST && oif_check)
1784                 fib_select_default(fl4, res);
1785
1786         if (!fl4->saddr)
1787                 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1788 }
1789 EXPORT_SYMBOL_GPL(fib_select_path);