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
 212         change_nexthops(fi) {
 213                 if (nexthop_nh->nh_dev)
 214                         dev_put(nexthop_nh->nh_dev);
 215                 lwtstate_put(nexthop_nh->nh_lwtstate);
 216                 free_nh_exceptions(nexthop_nh);
 217                 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
 218                 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
 219         } endfor_nexthops(fi);
 220
 221         ip_fib_metrics_put(fi->fib_metrics);
 222
 223         kfree(fi);
 224 }
 225
 226 void free_fib_info(struct fib_info *fi)
 227 {
 228         if (fi->fib_dead == 0) {
 229                 pr_warn("Freeing alive fib_info %p\n", fi);
 230                 return;
 231         }
 232         fib_info_cnt--;
 233 #ifdef CONFIG_IP_ROUTE_CLASSID
 234         change_nexthops(fi) {
 235                 if (nexthop_nh->nh_tclassid)
 236                         fi->fib_net->ipv4.fib_num_tclassid_users--;
 237         } endfor_nexthops(fi);
 238 #endif
 239         call_rcu(&fi->rcu, free_fib_info_rcu);
 240 }
 241 EXPORT_SYMBOL_GPL(free_fib_info);
 242
 243 void fib_release_info(struct fib_info *fi)
 244 {
 245         spin_lock_bh(&fib_info_lock);
 246         if (fi && --fi->fib_treeref == 0) {
 247                 hlist_del(&fi->fib_hash);
 248                 if (fi->fib_prefsrc)
 249                         hlist_del(&fi->fib_lhash);
 250                 change_nexthops(fi) {
 251                         if (!nexthop_nh->nh_dev)
 252                                 continue;
 253                         hlist_del(&nexthop_nh->nh_hash);
 254                 } endfor_nexthops(fi)
 255                 fi->fib_dead = 1;
 256                 fib_info_put(fi);
 257         }
 258         spin_unlock_bh(&fib_info_lock);
 259 }
 260
 261 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
 262 {
 263         const struct fib_nh *onh = ofi->fib_nh;
 264
 265         for_nexthops(fi) {
 266                 if (nh->nh_oif != onh->nh_oif ||
 267                     nh->nh_gw  != onh->nh_gw ||
 268                     nh->nh_scope != onh->nh_scope ||
 269 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 270                     nh->nh_weight != onh->nh_weight ||
 271 #endif
 272 #ifdef CONFIG_IP_ROUTE_CLASSID
 273                     nh->nh_tclassid != onh->nh_tclassid ||
 274 #endif
 275                     lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
 276                     ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
 277                         return -1;
 278                 onh++;
 279         } endfor_nexthops(fi);
 280         return 0;
 281 }
 282
 283 static inline unsigned int fib_devindex_hashfn(unsigned int val)
 284 {
 285         unsigned int mask = DEVINDEX_HASHSIZE - 1;
 286
 287         return (val ^
 288                 (val >> DEVINDEX_HASHBITS) ^
 289                 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
 290 }
 291
 292 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
 293 {
 294         unsigned int mask = (fib_info_hash_size - 1);
 295         unsigned int val = fi->fib_nhs;
 296
 297         val ^= (fi->fib_protocol << 8) | fi->fib_scope;
 298         val ^= (__force u32)fi->fib_prefsrc;
 299         val ^= fi->fib_priority;
 300         for_nexthops(fi) {
 301                 val ^= fib_devindex_hashfn(nh->nh_oif);
 302         } endfor_nexthops(fi)
 303
 304         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 305 }
 306
 307 static struct fib_info *fib_find_info(const struct fib_info *nfi)
 308 {
 309         struct hlist_head *head;
 310         struct fib_info *fi;
 311         unsigned int hash;
 312
 313         hash = fib_info_hashfn(nfi);
 314         head = &fib_info_hash[hash];
 315
 316         hlist_for_each_entry(fi, head, fib_hash) {
 317                 if (!net_eq(fi->fib_net, nfi->fib_net))
 318                         continue;
 319                 if (fi->fib_nhs != nfi->fib_nhs)
 320                         continue;
 321                 if (nfi->fib_protocol == fi->fib_protocol &&
 322                     nfi->fib_scope == fi->fib_scope &&
 323                     nfi->fib_prefsrc == fi->fib_prefsrc &&
 324                     nfi->fib_priority == fi->fib_priority &&
 325                     nfi->fib_type == fi->fib_type &&
 326                     memcmp(nfi->fib_metrics, fi->fib_metrics,
 327                            sizeof(u32) * RTAX_MAX) == 0 &&
 328                     !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 329                     (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
 330                         return fi;
 331         }
 332
 333         return NULL;
 334 }
 335
 336 /* Check, that the gateway is already configured.
 337  * Used only by redirect accept routine.
 338  */
 339 int ip_fib_check_default(__be32 gw, struct net_device *dev)
 340 {
 341         struct hlist_head *head;
 342         struct fib_nh *nh;
 343         unsigned int hash;
 344
 345         spin_lock(&fib_info_lock);
 346
 347         hash = fib_devindex_hashfn(dev->ifindex);
 348         head = &fib_info_devhash[hash];
 349         hlist_for_each_entry(nh, head, nh_hash) {
 350                 if (nh->nh_dev == dev &&
 351                     nh->nh_gw == gw &&
 352                     !(nh->nh_flags & RTNH_F_DEAD)) {
 353                         spin_unlock(&fib_info_lock);
 354                         return 0;
 355                 }
 356         }
 357
 358         spin_unlock(&fib_info_lock);
 359
 360         return -1;
 361 }
 362
 363 static inline size_t fib_nlmsg_size(struct fib_info *fi)
 364 {
 365         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 366                          + nla_total_size(4) /* RTA_TABLE */
 367                          + nla_total_size(4) /* RTA_DST */
 368                          + nla_total_size(4) /* RTA_PRIORITY */
 369                          + nla_total_size(4) /* RTA_PREFSRC */
 370                          + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 371
 372         /* space for nested metrics */
 373         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 374
 375         if (fi->fib_nhs) {
 376                 size_t nh_encapsize = 0;
 377                 /* Also handles the special case fib_nhs == 1 */
 378
 379                 /* each nexthop is packed in an attribute */
 380                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 381
 382                 /* may contain flow and gateway attribute */
 383                 nhsize += 2 * nla_total_size(4);
 384
 385                 /* grab encap info */
 386                 for_nexthops(fi) {
 387                         if (nh->nh_lwtstate) {
 388                                 /* RTA_ENCAP_TYPE */
 389                                 nh_encapsize += lwtunnel_get_encap_size(
 390                                                 nh->nh_lwtstate);
 391                                 /* RTA_ENCAP */
 392                                 nh_encapsize +=  nla_total_size(2);
 393                         }
 394                 } endfor_nexthops(fi);
 395
 396                 /* all nexthops are packed in a nested attribute */
 397                 payload += nla_total_size((fi->fib_nhs * nhsize) +
 398                                           nh_encapsize);
 399
 400         }
 401
 402         return payload;
 403 }
 404
 405 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 406                int dst_len, u32 tb_id, const struct nl_info *info,
 407                unsigned int nlm_flags)
 408 {
 409         struct sk_buff *skb;
 410         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 411         int err = -ENOBUFS;
 412
 413         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 414         if (!skb)
 415                 goto errout;
 416
 417         err = fib_dump_info(skb, info->portid, seq, event, tb_id,
 418                             fa->fa_type, key, dst_len,
 419                             fa->fa_tos, fa->fa_info, nlm_flags);
 420         if (err < 0) {
 421                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 422                 WARN_ON(err == -EMSGSIZE);
 423                 kfree_skb(skb);
 424                 goto errout;
 425         }
 426         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 427                     info->nlh, GFP_KERNEL);
 428         return;
 429 errout:
 430         if (err < 0)
 431                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 432 }
 433
 434 static int fib_detect_death(struct fib_info *fi, int order,
 435                             struct fib_info **last_resort, int *last_idx,
 436                             int dflt)
 437 {
 438         struct neighbour *n;
 439         int state = NUD_NONE;
 440
 441         n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
 442         if (n) {
 443                 state = n->nud_state;
 444                 neigh_release(n);
 445         } else {
 446                 return 0;
 447         }
 448         if (state == NUD_REACHABLE)
 449                 return 0;
 450         if ((state & NUD_VALID) && order != dflt)
 451                 return 0;
 452         if ((state & NUD_VALID) ||
 453             (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 454                 *last_resort = fi;
 455                 *last_idx = order;
 456         }
 457         return 1;
 458 }
 459
 460 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 461
 462 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 463                               struct netlink_ext_ack *extack)
 464 {
 465         int nhs = 0;
 466
 467         while (rtnh_ok(rtnh, remaining)) {
 468                 nhs++;
 469                 rtnh = rtnh_next(rtnh, &remaining);
 470         }
 471
 472         /* leftover implies invalid nexthop configuration, discard it */
 473         if (remaining > 0) {
 474                 NL_SET_ERR_MSG(extack,
 475                                "Invalid nexthop configuration - extra data after nexthops");
 476                 nhs = 0;
 477         }
 478
 479         return nhs;
 480 }
 481
 482 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 483                        int remaining, struct fib_config *cfg,
 484                        struct netlink_ext_ack *extack)
 485 {
 486         int ret;
 487
 488         change_nexthops(fi) {
 489                 int attrlen;
 490
 491                 if (!rtnh_ok(rtnh, remaining)) {
 492                         NL_SET_ERR_MSG(extack,
 493                                        "Invalid nexthop configuration - extra data after nexthop");
 494                         return -EINVAL;
 495                 }
 496
 497                 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 498                         NL_SET_ERR_MSG(extack,
 499                                        "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 500                         return -EINVAL;
 501                 }
 502
 503                 nexthop_nh->nh_flags =
 504                         (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 505                 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
 506                 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
 507
 508                 attrlen = rtnh_attrlen(rtnh);
 509                 if (attrlen > 0) {
 510                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
 511
 512                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 513                         nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
 514 #ifdef CONFIG_IP_ROUTE_CLASSID
 515                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 516                         nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
 517                         if (nexthop_nh->nh_tclassid)
 518                                 fi->fib_net->ipv4.fib_num_tclassid_users++;
 519 #endif
 520                         nla = nla_find(attrs, attrlen, RTA_ENCAP);
 521                         if (nla) {
 522                                 struct lwtunnel_state *lwtstate;
 523                                 struct nlattr *nla_entype;
 524
 525                                 nla_entype = nla_find(attrs, attrlen,
 526                                                       RTA_ENCAP_TYPE);
 527                                 if (!nla_entype) {
 528                                         NL_SET_BAD_ATTR(extack, nla);
 529                                         NL_SET_ERR_MSG(extack,
 530                                                        "Encap type is missing");
 531                                         goto err_inval;
 532                                 }
 533
 534                                 ret = lwtunnel_build_state(nla_get_u16(
 535                                                            nla_entype),
 536                                                            nla,  AF_INET, cfg,
 537                                                            &lwtstate, extack);
 538                                 if (ret)
 539                                         goto errout;
 540                                 nexthop_nh->nh_lwtstate =
 541                                         lwtstate_get(lwtstate);
 542                         }
 543                 }
 544
 545                 rtnh = rtnh_next(rtnh, &remaining);
 546         } endfor_nexthops(fi);
 547
 548         return 0;
 549
 550 err_inval:
 551         ret = -EINVAL;
 552
 553 errout:
 554         return ret;
 555 }
 556
 557 static void fib_rebalance(struct fib_info *fi)
 558 {
 559         int total;
 560         int w;
 561         struct in_device *in_dev;
 562
 563         if (fi->fib_nhs < 2)
 564                 return;
 565
 566         total = 0;
 567         for_nexthops(fi) {
 568                 if (nh->nh_flags & RTNH_F_DEAD)
 569                         continue;
 570
 571                 in_dev = __in_dev_get_rtnl(nh->nh_dev);
 572
 573                 if (in_dev &&
 574                     IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
 575                     nh->nh_flags & RTNH_F_LINKDOWN)
 576                         continue;
 577
 578                 total += nh->nh_weight;
 579         } endfor_nexthops(fi);
 580
 581         w = 0;
 582         change_nexthops(fi) {
 583                 int upper_bound;
 584
 585                 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
 586
 587                 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
 588                         upper_bound = -1;
 589                 } else if (in_dev &&
 590                            IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
 591                            nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
 592                         upper_bound = -1;
 593                 } else {
 594                         w += nexthop_nh->nh_weight;
 595                         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 596                                                             total) - 1;
 597                 }
 598
 599                 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
 600         } endfor_nexthops(fi);
 601 }
 602 #else /* CONFIG_IP_ROUTE_MULTIPATH */
 603
 604 #define fib_rebalance(fi) do { } while (0)
 605
 606 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
 607
 608 static int fib_encap_match(u16 encap_type,
 609                            struct nlattr *encap,
 610                            const struct fib_nh *nh,
 611                            const struct fib_config *cfg,
 612                            struct netlink_ext_ack *extack)
 613 {
 614         struct lwtunnel_state *lwtstate;
 615         int ret, result = 0;
 616
 617         if (encap_type == LWTUNNEL_ENCAP_NONE)
 618                 return 0;
 619
 620         ret = lwtunnel_build_state(encap_type, encap, AF_INET,
 621                                    cfg, &lwtstate, extack);
 622         if (!ret) {
 623                 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
 624                 lwtstate_free(lwtstate);
 625         }
 626
 627         return result;
 628 }
 629
 630 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
 631                  struct netlink_ext_ack *extack)
 632 {
 633 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 634         struct rtnexthop *rtnh;
 635         int remaining;
 636 #endif
 637
 638         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 639                 return 1;
 640
 641         if (cfg->fc_oif || cfg->fc_gw) {
 642                 if (cfg->fc_encap) {
 643                         if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
 644                                             fi->fib_nh, cfg, extack))
 645                                 return 1;
 646                 }
 647 #ifdef CONFIG_IP_ROUTE_CLASSID
 648                 if (cfg->fc_flow &&
 649                     cfg->fc_flow != fi->fib_nh->nh_tclassid)
 650                         return 1;
 651 #endif
 652                 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
 653                     (!cfg->fc_gw  || cfg->fc_gw == fi->fib_nh->nh_gw))
 654                         return 0;
 655                 return 1;
 656         }
 657
 658 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 659         if (!cfg->fc_mp)
 660                 return 0;
 661
 662         rtnh = cfg->fc_mp;
 663         remaining = cfg->fc_mp_len;
 664
 665         for_nexthops(fi) {
 666                 int attrlen;
 667
 668                 if (!rtnh_ok(rtnh, remaining))
 669                         return -EINVAL;
 670
 671                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
 672                         return 1;
 673
 674                 attrlen = rtnh_attrlen(rtnh);
 675                 if (attrlen > 0) {
 676                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
 677
 678                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 679                         if (nla && nla_get_in_addr(nla) != nh->nh_gw)
 680                                 return 1;
 681 #ifdef CONFIG_IP_ROUTE_CLASSID
 682                         nla = nla_find(attrs, attrlen, RTA_FLOW);
 683                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 684                                 return 1;
 685 #endif
 686                 }
 687
 688                 rtnh = rtnh_next(rtnh, &remaining);
 689         } endfor_nexthops(fi);
 690 #endif
 691         return 0;
 692 }
 693
 694 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 695 {
 696         struct nlattr *nla;
 697         int remaining;
 698
 699         if (!cfg->fc_mx)
 700                 return true;
 701
 702         nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 703                 int type = nla_type(nla);
 704                 u32 fi_val, val;
 705
 706                 if (!type)
 707                         continue;
 708                 if (type > RTAX_MAX)
 709                         return false;
 710
 711                 if (type == RTAX_CC_ALGO) {
 712                         char tmp[TCP_CA_NAME_MAX];
 713                         bool ecn_ca = false;
 714
 715                         nla_strlcpy(tmp, nla, sizeof(tmp));
 716                         val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 717                 } else {
 718                         if (nla_len(nla) != sizeof(u32))
 719                                 return false;
 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                                 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
 800                                 return -ENODEV;
 801                         }
 802                         if (!(dev->flags & IFF_UP)) {
 803                                 NL_SET_ERR_MSG(extack,
 804                                                "Nexthop device is not up");
 805                                 return -ENETDOWN;
 806                         }
 807                         addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
 808                         if (addr_type != RTN_UNICAST) {
 809                                 NL_SET_ERR_MSG(extack,
 810                                                "Nexthop has invalid gateway");
 811                                 return -EINVAL;
 812                         }
 813                         if (!netif_carrier_ok(dev))
 814                                 nh->nh_flags |= RTNH_F_LINKDOWN;
 815                         nh->nh_dev = dev;
 816                         dev_hold(dev);
 817                         nh->nh_scope = RT_SCOPE_LINK;
 818                         return 0;
 819                 }
 820                 rcu_read_lock();
 821                 {
 822                         struct fib_table *tbl = NULL;
 823                         struct flowi4 fl4 = {
 824                                 .daddr = nh->nh_gw,
 825                                 .flowi4_scope = cfg->fc_scope + 1,
 826                                 .flowi4_oif = nh->nh_oif,
 827                                 .flowi4_iif = LOOPBACK_IFINDEX,
 828                         };
 829
 830                         /* It is not necessary, but requires a bit of thinking */
 831                         if (fl4.flowi4_scope < RT_SCOPE_LINK)
 832                                 fl4.flowi4_scope = RT_SCOPE_LINK;
 833
 834                         if (cfg->fc_table)
 835                                 tbl = fib_get_table(net, cfg->fc_table);
 836
 837                         if (tbl)
 838                                 err = fib_table_lookup(tbl, &fl4, &res,
 839                                                        FIB_LOOKUP_IGNORE_LINKSTATE |
 840                                                        FIB_LOOKUP_NOREF);
 841
 842                         /* on error or if no table given do full lookup. This
 843                          * is needed for example when nexthops are in the local
 844                          * table rather than the given table
 845                          */
 846                         if (!tbl || err) {
 847                                 err = fib_lookup(net, &fl4, &res,
 848                                                  FIB_LOOKUP_IGNORE_LINKSTATE);
 849                         }
 850
 851                         if (err) {
 852                                 NL_SET_ERR_MSG(extack,
 853                                                "Nexthop has invalid gateway");
 854                                 rcu_read_unlock();
 855                                 return err;
 856                         }
 857                 }
 858                 err = -EINVAL;
 859                 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
 860                         NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
 861                         goto out;
 862                 }
 863                 nh->nh_scope = res.scope;
 864                 nh->nh_oif = FIB_RES_OIF(res);
 865                 nh->nh_dev = dev = FIB_RES_DEV(res);
 866                 if (!dev) {
 867                         NL_SET_ERR_MSG(extack,
 868                                        "No egress device for nexthop gateway");
 869                         goto out;
 870                 }
 871                 dev_hold(dev);
 872                 if (!netif_carrier_ok(dev))
 873                         nh->nh_flags |= RTNH_F_LINKDOWN;
 874                 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
 875         } else {
 876                 struct in_device *in_dev;
 877
 878                 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
 879                         NL_SET_ERR_MSG(extack,
 880                                        "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
 881                         return -EINVAL;
 882                 }
 883                 rcu_read_lock();
 884                 err = -ENODEV;
 885                 in_dev = inetdev_by_index(net, nh->nh_oif);
 886                 if (!in_dev)
 887                         goto out;
 888                 err = -ENETDOWN;
 889                 if (!(in_dev->dev->flags & IFF_UP)) {
 890                         NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
 891                         goto out;
 892                 }
 893                 nh->nh_dev = in_dev->dev;
 894                 dev_hold(nh->nh_dev);
 895                 nh->nh_scope = RT_SCOPE_HOST;
 896                 if (!netif_carrier_ok(nh->nh_dev))
 897                         nh->nh_flags |= RTNH_F_LINKDOWN;
 898                 err = 0;
 899         }
 900 out:
 901         rcu_read_unlock();
 902         return err;
 903 }
 904
 905 static inline unsigned int fib_laddr_hashfn(__be32 val)
 906 {
 907         unsigned int mask = (fib_info_hash_size - 1);
 908
 909         return ((__force u32)val ^
 910                 ((__force u32)val >> 7) ^
 911                 ((__force u32)val >> 14)) & mask;
 912 }
 913
 914 static struct hlist_head *fib_info_hash_alloc(int bytes)
 915 {
 916         if (bytes <= PAGE_SIZE)
 917                 return kzalloc(bytes, GFP_KERNEL);
 918         else
 919                 return (struct hlist_head *)
 920                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
 921                                          get_order(bytes));
 922 }
 923
 924 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
 925 {
 926         if (!hash)
 927                 return;
 928
 929         if (bytes <= PAGE_SIZE)
 930                 kfree(hash);
 931         else
 932                 free_pages((unsigned long) hash, get_order(bytes));
 933 }
 934
 935 static void fib_info_hash_move(struct hlist_head *new_info_hash,
 936                                struct hlist_head *new_laddrhash,
 937                                unsigned int new_size)
 938 {
 939         struct hlist_head *old_info_hash, *old_laddrhash;
 940         unsigned int old_size = fib_info_hash_size;
 941         unsigned int i, bytes;
 942
 943         spin_lock_bh(&fib_info_lock);
 944         old_info_hash = fib_info_hash;
 945         old_laddrhash = fib_info_laddrhash;
 946         fib_info_hash_size = new_size;
 947
 948         for (i = 0; i < old_size; i++) {
 949                 struct hlist_head *head = &fib_info_hash[i];
 950                 struct hlist_node *n;
 951                 struct fib_info *fi;
 952
 953                 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
 954                         struct hlist_head *dest;
 955                         unsigned int new_hash;
 956
 957                         new_hash = fib_info_hashfn(fi);
 958                         dest = &new_info_hash[new_hash];
 959                         hlist_add_head(&fi->fib_hash, dest);
 960                 }
 961         }
 962         fib_info_hash = new_info_hash;
 963
 964         for (i = 0; i < old_size; i++) {
 965                 struct hlist_head *lhead = &fib_info_laddrhash[i];
 966                 struct hlist_node *n;
 967                 struct fib_info *fi;
 968
 969                 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
 970                         struct hlist_head *ldest;
 971                         unsigned int new_hash;
 972
 973                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
 974                         ldest = &new_laddrhash[new_hash];
 975                         hlist_add_head(&fi->fib_lhash, ldest);
 976                 }
 977         }
 978         fib_info_laddrhash = new_laddrhash;
 979
 980         spin_unlock_bh(&fib_info_lock);
 981
 982         bytes = old_size * sizeof(struct hlist_head *);
 983         fib_info_hash_free(old_info_hash, bytes);
 984         fib_info_hash_free(old_laddrhash, bytes);
 985 }
 986
 987 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
 988 {
 989         nh->nh_saddr = inet_select_addr(nh->nh_dev,
 990                                         nh->nh_gw,
 991                                         nh->nh_parent->fib_scope);
 992         nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
 993
 994         return nh->nh_saddr;
 995 }
 996
 997 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
 998 {
 999         if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1000             fib_prefsrc != cfg->fc_dst) {
1001                 u32 tb_id = cfg->fc_table;
1002                 int rc;
1003
1004                 if (tb_id == RT_TABLE_MAIN)
1005                         tb_id = RT_TABLE_LOCAL;
1006
1007                 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1008                                           fib_prefsrc, tb_id);
1009
1010                 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1011                         rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1012                                                   fib_prefsrc, RT_TABLE_LOCAL);
1013                 }
1014
1015                 if (rc != RTN_LOCAL)
1016                         return false;
1017         }
1018         return true;
1019 }
1020
1021 struct fib_info *fib_create_info(struct fib_config *cfg,
1022                                  struct netlink_ext_ack *extack)
1023 {
1024         int err;
1025         struct fib_info *fi = NULL;
1026         struct fib_info *ofi;
1027         int nhs = 1;
1028         struct net *net = cfg->fc_nlinfo.nl_net;
1029
1030         if (cfg->fc_type > RTN_MAX)
1031                 goto err_inval;
1032
1033         /* Fast check to catch the most weird cases */
1034         if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1035                 NL_SET_ERR_MSG(extack, "Invalid scope");
1036                 goto err_inval;
1037         }
1038
1039         if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1040                 NL_SET_ERR_MSG(extack,
1041                                "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1042                 goto err_inval;
1043         }
1044
1045 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1046         if (cfg->fc_mp) {
1047                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1048                 if (nhs == 0)
1049                         goto err_inval;
1050         }
1051 #endif
1052
1053         err = -ENOBUFS;
1054         if (fib_info_cnt >= fib_info_hash_size) {
1055                 unsigned int new_size = fib_info_hash_size << 1;
1056                 struct hlist_head *new_info_hash;
1057                 struct hlist_head *new_laddrhash;
1058                 unsigned int bytes;
1059
1060                 if (!new_size)
1061                         new_size = 16;
1062                 bytes = new_size * sizeof(struct hlist_head *);
1063                 new_info_hash = fib_info_hash_alloc(bytes);
1064                 new_laddrhash = fib_info_hash_alloc(bytes);
1065                 if (!new_info_hash || !new_laddrhash) {
1066                         fib_info_hash_free(new_info_hash, bytes);
1067                         fib_info_hash_free(new_laddrhash, bytes);
1068                 } else
1069                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1070
1071                 if (!fib_info_hash_size)
1072                         goto failure;
1073         }
1074
1075         fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1076         if (!fi)
1077                 goto failure;
1078         fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1079                                               cfg->fc_mx_len);
1080         if (unlikely(IS_ERR(fi->fib_metrics))) {
1081                 err = PTR_ERR(fi->fib_metrics);
1082                 kfree(fi);
1083                 return ERR_PTR(err);
1084         }
1085
1086         fib_info_cnt++;
1087         fi->fib_net = net;
1088         fi->fib_protocol = cfg->fc_protocol;
1089         fi->fib_scope = cfg->fc_scope;
1090         fi->fib_flags = cfg->fc_flags;
1091         fi->fib_priority = cfg->fc_priority;
1092         fi->fib_prefsrc = cfg->fc_prefsrc;
1093         fi->fib_type = cfg->fc_type;
1094         fi->fib_tb_id = cfg->fc_table;
1095
1096         fi->fib_nhs = nhs;
1097         change_nexthops(fi) {
1098                 nexthop_nh->nh_parent = fi;
1099                 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1100                 if (!nexthop_nh->nh_pcpu_rth_output)
1101                         goto failure;
1102         } endfor_nexthops(fi)
1103
1104         if (cfg->fc_mp) {
1105 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1106                 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1107                 if (err != 0)
1108                         goto failure;
1109                 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1110                         NL_SET_ERR_MSG(extack,
1111                                        "Nexthop device index does not match RTA_OIF");
1112                         goto err_inval;
1113                 }
1114                 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1115                         NL_SET_ERR_MSG(extack,
1116                                        "Nexthop gateway does not match RTA_GATEWAY");
1117                         goto err_inval;
1118                 }
1119 #ifdef CONFIG_IP_ROUTE_CLASSID
1120                 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1121                         NL_SET_ERR_MSG(extack,
1122                                        "Nexthop class id does not match RTA_FLOW");
1123                         goto err_inval;
1124                 }
1125 #endif
1126 #else
1127                 NL_SET_ERR_MSG(extack,
1128                                "Multipath support not enabled in kernel");
1129                 goto err_inval;
1130 #endif
1131         } else {
1132                 struct fib_nh *nh = fi->fib_nh;
1133
1134                 if (cfg->fc_encap) {
1135                         struct lwtunnel_state *lwtstate;
1136
1137                         if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1138                                 NL_SET_ERR_MSG(extack,
1139                                                "LWT encap type not specified");
1140                                 goto err_inval;
1141                         }
1142                         err = lwtunnel_build_state(cfg->fc_encap_type,
1143                                                    cfg->fc_encap, AF_INET, cfg,
1144                                                    &lwtstate, extack);
1145                         if (err)
1146                                 goto failure;
1147
1148                         nh->nh_lwtstate = lwtstate_get(lwtstate);
1149                 }
1150                 nh->nh_oif = cfg->fc_oif;
1151                 nh->nh_gw = cfg->fc_gw;
1152                 nh->nh_flags = cfg->fc_flags;
1153 #ifdef CONFIG_IP_ROUTE_CLASSID
1154                 nh->nh_tclassid = cfg->fc_flow;
1155                 if (nh->nh_tclassid)
1156                         fi->fib_net->ipv4.fib_num_tclassid_users++;
1157 #endif
1158 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1159                 nh->nh_weight = 1;
1160 #endif
1161         }
1162
1163         if (fib_props[cfg->fc_type].error) {
1164                 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1165                         NL_SET_ERR_MSG(extack,
1166                                        "Gateway, device and multipath can not be specified for this route type");
1167                         goto err_inval;
1168                 }
1169                 goto link_it;
1170         } else {
1171                 switch (cfg->fc_type) {
1172                 case RTN_UNICAST:
1173                 case RTN_LOCAL:
1174                 case RTN_BROADCAST:
1175                 case RTN_ANYCAST:
1176                 case RTN_MULTICAST:
1177                         break;
1178                 default:
1179                         NL_SET_ERR_MSG(extack, "Invalid route type");
1180                         goto err_inval;
1181                 }
1182         }
1183
1184         if (cfg->fc_scope > RT_SCOPE_HOST) {
1185                 NL_SET_ERR_MSG(extack, "Invalid scope");
1186                 goto err_inval;
1187         }
1188
1189         if (cfg->fc_scope == RT_SCOPE_HOST) {
1190                 struct fib_nh *nh = fi->fib_nh;
1191
1192                 /* Local address is added. */
1193                 if (nhs != 1) {
1194                         NL_SET_ERR_MSG(extack,
1195                                        "Route with host scope can not have multiple nexthops");
1196                         goto err_inval;
1197                 }
1198                 if (nh->nh_gw) {
1199                         NL_SET_ERR_MSG(extack,
1200                                        "Route with host scope can not have a gateway");
1201                         goto err_inval;
1202                 }
1203                 nh->nh_scope = RT_SCOPE_NOWHERE;
1204                 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1205                 err = -ENODEV;
1206                 if (!nh->nh_dev)
1207                         goto failure;
1208         } else {
1209                 int linkdown = 0;
1210
1211                 change_nexthops(fi) {
1212                         err = fib_check_nh(cfg, nexthop_nh, extack);
1213                         if (err != 0)
1214                                 goto failure;
1215                         if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1216                                 linkdown++;
1217                 } endfor_nexthops(fi)
1218                 if (linkdown == fi->fib_nhs)
1219                         fi->fib_flags |= RTNH_F_LINKDOWN;
1220         }
1221
1222         if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1223                 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1224                 goto err_inval;
1225         }
1226
1227         change_nexthops(fi) {
1228                 fib_info_update_nh_saddr(net, nexthop_nh);
1229         } endfor_nexthops(fi)
1230
1231         fib_rebalance(fi);
1232
1233 link_it:
1234         ofi = fib_find_info(fi);
1235         if (ofi) {
1236                 fi->fib_dead = 1;
1237                 free_fib_info(fi);
1238                 ofi->fib_treeref++;
1239                 return ofi;
1240         }
1241
1242         fi->fib_treeref++;
1243         refcount_set(&fi->fib_clntref, 1);
1244         spin_lock_bh(&fib_info_lock);
1245         hlist_add_head(&fi->fib_hash,
1246                        &fib_info_hash[fib_info_hashfn(fi)]);
1247         if (fi->fib_prefsrc) {
1248                 struct hlist_head *head;
1249
1250                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1251                 hlist_add_head(&fi->fib_lhash, head);
1252         }
1253         change_nexthops(fi) {
1254                 struct hlist_head *head;
1255                 unsigned int hash;
1256
1257                 if (!nexthop_nh->nh_dev)
1258                         continue;
1259                 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1260                 head = &fib_info_devhash[hash];
1261                 hlist_add_head(&nexthop_nh->nh_hash, head);
1262         } endfor_nexthops(fi)
1263         spin_unlock_bh(&fib_info_lock);
1264         return fi;
1265
1266 err_inval:
1267         err = -EINVAL;
1268
1269 failure:
1270         if (fi) {
1271                 fi->fib_dead = 1;
1272                 free_fib_info(fi);
1273         }
1274
1275         return ERR_PTR(err);
1276 }
1277
1278 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1279                   u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1280                   struct fib_info *fi, unsigned int flags)
1281 {
1282         struct nlmsghdr *nlh;
1283         struct rtmsg *rtm;
1284
1285         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1286         if (!nlh)
1287                 return -EMSGSIZE;
1288
1289         rtm = nlmsg_data(nlh);
1290         rtm->rtm_family = AF_INET;
1291         rtm->rtm_dst_len = dst_len;
1292         rtm->rtm_src_len = 0;
1293         rtm->rtm_tos = tos;
1294         if (tb_id < 256)
1295                 rtm->rtm_table = tb_id;
1296         else
1297                 rtm->rtm_table = RT_TABLE_COMPAT;
1298         if (nla_put_u32(skb, RTA_TABLE, tb_id))
1299                 goto nla_put_failure;
1300         rtm->rtm_type = type;
1301         rtm->rtm_flags = fi->fib_flags;
1302         rtm->rtm_scope = fi->fib_scope;
1303         rtm->rtm_protocol = fi->fib_protocol;
1304
1305         if (rtm->rtm_dst_len &&
1306             nla_put_in_addr(skb, RTA_DST, dst))
1307                 goto nla_put_failure;
1308         if (fi->fib_priority &&
1309             nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1310                 goto nla_put_failure;
1311         if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1312                 goto nla_put_failure;
1313
1314         if (fi->fib_prefsrc &&
1315             nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1316                 goto nla_put_failure;
1317         if (fi->fib_nhs == 1) {
1318                 if (fi->fib_nh->nh_gw &&
1319                     nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1320                         goto nla_put_failure;
1321                 if (fi->fib_nh->nh_oif &&
1322                     nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1323                         goto nla_put_failure;
1324                 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1325                         struct in_device *in_dev;
1326
1327                         rcu_read_lock();
1328                         in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1329                         if (in_dev &&
1330                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1331                                 rtm->rtm_flags |= RTNH_F_DEAD;
1332                         rcu_read_unlock();
1333                 }
1334                 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1335                         rtm->rtm_flags |= RTNH_F_OFFLOAD;
1336 #ifdef CONFIG_IP_ROUTE_CLASSID
1337                 if (fi->fib_nh[0].nh_tclassid &&
1338                     nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1339                         goto nla_put_failure;
1340 #endif
1341                 if (fi->fib_nh->nh_lwtstate &&
1342                     lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1343                         goto nla_put_failure;
1344         }
1345 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1346         if (fi->fib_nhs > 1) {
1347                 struct rtnexthop *rtnh;
1348                 struct nlattr *mp;
1349
1350                 mp = nla_nest_start(skb, RTA_MULTIPATH);
1351                 if (!mp)
1352                         goto nla_put_failure;
1353
1354                 for_nexthops(fi) {
1355                         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1356                         if (!rtnh)
1357                                 goto nla_put_failure;
1358
1359                         rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1360                         if (nh->nh_flags & RTNH_F_LINKDOWN) {
1361                                 struct in_device *in_dev;
1362
1363                                 rcu_read_lock();
1364                                 in_dev = __in_dev_get_rcu(nh->nh_dev);
1365                                 if (in_dev &&
1366                                     IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1367                                         rtnh->rtnh_flags |= RTNH_F_DEAD;
1368                                 rcu_read_unlock();
1369                         }
1370                         rtnh->rtnh_hops = nh->nh_weight - 1;
1371                         rtnh->rtnh_ifindex = nh->nh_oif;
1372
1373                         if (nh->nh_gw &&
1374                             nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1375                                 goto nla_put_failure;
1376 #ifdef CONFIG_IP_ROUTE_CLASSID
1377                         if (nh->nh_tclassid &&
1378                             nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1379                                 goto nla_put_failure;
1380 #endif
1381                         if (nh->nh_lwtstate &&
1382                             lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1383                                 goto nla_put_failure;
1384
1385                         /* length of rtnetlink header + attributes */
1386                         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1387                 } endfor_nexthops(fi);
1388
1389                 nla_nest_end(skb, mp);
1390         }
1391 #endif
1392         nlmsg_end(skb, nlh);
1393         return 0;
1394
1395 nla_put_failure:
1396         nlmsg_cancel(skb, nlh);
1397         return -EMSGSIZE;
1398 }
1399
1400 /*
1401  * Update FIB if:
1402  * - local address disappeared -> we must delete all the entries
1403  *   referring to it.
1404  * - device went down -> we must shutdown all nexthops going via it.
1405  */
1406 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1407 {
1408         int ret = 0;
1409         unsigned int hash = fib_laddr_hashfn(local);
1410         struct hlist_head *head = &fib_info_laddrhash[hash];
1411         struct net *net = dev_net(dev);
1412         int tb_id = l3mdev_fib_table(dev);
1413         struct fib_info *fi;
1414
1415         if (!fib_info_laddrhash || local == 0)
1416                 return 0;
1417
1418         hlist_for_each_entry(fi, head, fib_lhash) {
1419                 if (!net_eq(fi->fib_net, net) ||
1420                     fi->fib_tb_id != tb_id)
1421                         continue;
1422                 if (fi->fib_prefsrc == local) {
1423                         fi->fib_flags |= RTNH_F_DEAD;
1424                         ret++;
1425                 }
1426         }
1427         return ret;
1428 }
1429
1430 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1431                                  enum fib_event_type event_type)
1432 {
1433         struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1434         struct fib_nh_notifier_info info = {
1435                 .fib_nh = fib_nh,
1436         };
1437
1438         switch (event_type) {
1439         case FIB_EVENT_NH_ADD:
1440                 if (fib_nh->nh_flags & RTNH_F_DEAD)
1441                         break;
1442                 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1443                     fib_nh->nh_flags & RTNH_F_LINKDOWN)
1444                         break;
1445                 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1446                                            &info.info);
1447         case FIB_EVENT_NH_DEL:
1448                 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1449                      fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1450                     (fib_nh->nh_flags & RTNH_F_DEAD))
1451                         return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1452                                                    event_type, &info.info);
1453         default:
1454                 break;
1455         }
1456
1457         return NOTIFY_DONE;
1458 }
1459
1460 /* Update the PMTU of exceptions when:
1461  * - the new MTU of the first hop becomes smaller than the PMTU
1462  * - the old MTU was the same as the PMTU, and it limited discovery of
1463  *   larger MTUs on the path. With that limit raised, we can now
1464  *   discover larger MTUs
1465  * A special case is locked exceptions, for which the PMTU is smaller
1466  * than the minimal accepted PMTU:
1467  * - if the new MTU is greater than the PMTU, don't make any change
1468  * - otherwise, unlock and set PMTU
1469  */
1470 static void nh_update_mtu(struct fib_nh *nh, u32 new, u32 orig)
1471 {
1472         struct fnhe_hash_bucket *bucket;
1473         int i;
1474
1475         bucket = rcu_dereference_protected(nh->nh_exceptions, 1);
1476         if (!bucket)
1477                 return;
1478
1479         for (i = 0; i < FNHE_HASH_SIZE; i++) {
1480                 struct fib_nh_exception *fnhe;
1481
1482                 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1483                      fnhe;
1484                      fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1485                         if (fnhe->fnhe_mtu_locked) {
1486                                 if (new <= fnhe->fnhe_pmtu) {
1487                                         fnhe->fnhe_pmtu = new;
1488                                         fnhe->fnhe_mtu_locked = false;
1489                                 }
1490                         } else if (new < fnhe->fnhe_pmtu ||
1491                                    orig == fnhe->fnhe_pmtu) {
1492                                 fnhe->fnhe_pmtu = new;
1493                         }
1494                 }
1495         }
1496 }
1497
1498 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1499 {
1500         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1501         struct hlist_head *head = &fib_info_devhash[hash];
1502         struct fib_nh *nh;
1503
1504         hlist_for_each_entry(nh, head, nh_hash) {
1505                 if (nh->nh_dev == dev)
1506                         nh_update_mtu(nh, dev->mtu, orig_mtu);
1507         }
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 (net->ipv4.sysctl_fib_multipath_use_neigh) {
1750                         if (!fib_good_nh(nh))
1751                                 continue;
1752                         if (!first) {
1753                                 res->nh_sel = nhsel;
1754                                 first = true;
1755                         }
1756                 }
1757
1758                 if (hash > atomic_read(&nh->nh_upper_bound))
1759                         continue;
1760
1761                 res->nh_sel = nhsel;
1762                 return;
1763         } endfor_nexthops(fi);
1764 }
1765 #endif
1766
1767 void fib_select_path(struct net *net, struct fib_result *res,
1768                      struct flowi4 *fl4, const struct sk_buff *skb)
1769 {
1770         if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
1771                 goto check_saddr;
1772
1773 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1774         if (res->fi->fib_nhs > 1) {
1775                 int h = fib_multipath_hash(net, fl4, skb, NULL);
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)
1784                 fib_select_default(fl4, res);
1785
1786 check_saddr:
1787         if (!fl4->saddr)
1788                 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1789 }