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 36 #include <net/arp.h> 37 #include <net/ip.h> 38 #include <net/protocol.h> 39 #include <net/route.h> 40 #include <net/tcp.h> 41 #include <net/sock.h> 42 #include <net/ip_fib.h> 43 #include <net/netlink.h> 44 #include <net/nexthop.h> 45 #include <net/lwtunnel.h> 46 47 #include "fib_lookup.h" 48 49 static DEFINE_SPINLOCK(fib_info_lock); 50 static struct hlist_head *fib_info_hash; 51 static struct hlist_head *fib_info_laddrhash; 52 static unsigned int fib_info_hash_size; 53 static unsigned int fib_info_cnt; 54 55 #define DEVINDEX_HASHBITS 8 56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 58 59 #ifdef CONFIG_IP_ROUTE_MULTIPATH 60 u32 fib_multipath_secret __read_mostly; 61 62 #define for_nexthops(fi) { \ 63 int nhsel; const struct fib_nh *nh; \ 64 for (nhsel = 0, nh = (fi)->fib_nh; \ 65 nhsel < (fi)->fib_nhs; \ 66 nh++, nhsel++) 67 68 #define change_nexthops(fi) { \ 69 int nhsel; struct fib_nh *nexthop_nh; \ 70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 71 nhsel < (fi)->fib_nhs; \ 72 nexthop_nh++, nhsel++) 73 74 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 75 76 /* Hope, that gcc will optimize it to get rid of dummy loop */ 77 78 #define for_nexthops(fi) { \ 79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 80 for (nhsel = 0; nhsel < 1; nhsel++) 81 82 #define change_nexthops(fi) { \ 83 int nhsel; \ 84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 85 for (nhsel = 0; nhsel < 1; nhsel++) 86 87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 88 89 #define endfor_nexthops(fi) } 90 91 92 const struct fib_prop fib_props[RTN_MAX + 1] = { 93 [RTN_UNSPEC] = { 94 .error = 0, 95 .scope = RT_SCOPE_NOWHERE, 96 }, 97 [RTN_UNICAST] = { 98 .error = 0, 99 .scope = RT_SCOPE_UNIVERSE, 100 }, 101 [RTN_LOCAL] = { 102 .error = 0, 103 .scope = RT_SCOPE_HOST, 104 }, 105 [RTN_BROADCAST] = { 106 .error = 0, 107 .scope = RT_SCOPE_LINK, 108 }, 109 [RTN_ANYCAST] = { 110 .error = 0, 111 .scope = RT_SCOPE_LINK, 112 }, 113 [RTN_MULTICAST] = { 114 .error = 0, 115 .scope = RT_SCOPE_UNIVERSE, 116 }, 117 [RTN_BLACKHOLE] = { 118 .error = -EINVAL, 119 .scope = RT_SCOPE_UNIVERSE, 120 }, 121 [RTN_UNREACHABLE] = { 122 .error = -EHOSTUNREACH, 123 .scope = RT_SCOPE_UNIVERSE, 124 }, 125 [RTN_PROHIBIT] = { 126 .error = -EACCES, 127 .scope = RT_SCOPE_UNIVERSE, 128 }, 129 [RTN_THROW] = { 130 .error = -EAGAIN, 131 .scope = RT_SCOPE_UNIVERSE, 132 }, 133 [RTN_NAT] = { 134 .error = -EINVAL, 135 .scope = RT_SCOPE_NOWHERE, 136 }, 137 [RTN_XRESOLVE] = { 138 .error = -EINVAL, 139 .scope = RT_SCOPE_NOWHERE, 140 }, 141 }; 142 143 static void rt_fibinfo_free(struct rtable __rcu **rtp) 144 { 145 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 146 147 if (!rt) 148 return; 149 150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 151 * because we waited an RCU grace period before calling 152 * free_fib_info_rcu() 153 */ 154 155 dst_free(&rt->dst); 156 } 157 158 static void free_nh_exceptions(struct fib_nh *nh) 159 { 160 struct fnhe_hash_bucket *hash; 161 int i; 162 163 hash = rcu_dereference_protected(nh->nh_exceptions, 1); 164 if (!hash) 165 return; 166 for (i = 0; i < FNHE_HASH_SIZE; i++) { 167 struct fib_nh_exception *fnhe; 168 169 fnhe = rcu_dereference_protected(hash[i].chain, 1); 170 while (fnhe) { 171 struct fib_nh_exception *next; 172 173 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 174 175 rt_fibinfo_free(&fnhe->fnhe_rth_input); 176 rt_fibinfo_free(&fnhe->fnhe_rth_output); 177 178 kfree(fnhe); 179 180 fnhe = next; 181 } 182 } 183 kfree(hash); 184 } 185 186 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 187 { 188 int cpu; 189 190 if (!rtp) 191 return; 192 193 for_each_possible_cpu(cpu) { 194 struct rtable *rt; 195 196 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 197 if (rt) 198 dst_free(&rt->dst); 199 } 200 free_percpu(rtp); 201 } 202 203 /* Release a nexthop info record */ 204 static void free_fib_info_rcu(struct rcu_head *head) 205 { 206 struct fib_info *fi = container_of(head, struct fib_info, rcu); 207 208 change_nexthops(fi) { 209 if (nexthop_nh->nh_dev) 210 dev_put(nexthop_nh->nh_dev); 211 lwtstate_put(nexthop_nh->nh_lwtstate); 212 free_nh_exceptions(nexthop_nh); 213 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 214 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 215 } endfor_nexthops(fi); 216 217 if (fi->fib_metrics != (u32 *) dst_default_metrics) 218 kfree(fi->fib_metrics); 219 kfree(fi); 220 } 221 222 void free_fib_info(struct fib_info *fi) 223 { 224 if (fi->fib_dead == 0) { 225 pr_warn("Freeing alive fib_info %p\n", fi); 226 return; 227 } 228 fib_info_cnt--; 229 #ifdef CONFIG_IP_ROUTE_CLASSID 230 change_nexthops(fi) { 231 if (nexthop_nh->nh_tclassid) 232 fi->fib_net->ipv4.fib_num_tclassid_users--; 233 } endfor_nexthops(fi); 234 #endif 235 call_rcu(&fi->rcu, free_fib_info_rcu); 236 } 237 EXPORT_SYMBOL_GPL(free_fib_info); 238 239 void fib_release_info(struct fib_info *fi) 240 { 241 spin_lock_bh(&fib_info_lock); 242 if (fi && --fi->fib_treeref == 0) { 243 hlist_del(&fi->fib_hash); 244 if (fi->fib_prefsrc) 245 hlist_del(&fi->fib_lhash); 246 change_nexthops(fi) { 247 if (!nexthop_nh->nh_dev) 248 continue; 249 hlist_del(&nexthop_nh->nh_hash); 250 } endfor_nexthops(fi) 251 fi->fib_dead = 1; 252 fib_info_put(fi); 253 } 254 spin_unlock_bh(&fib_info_lock); 255 } 256 257 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 258 { 259 const struct fib_nh *onh = ofi->fib_nh; 260 261 for_nexthops(fi) { 262 if (nh->nh_oif != onh->nh_oif || 263 nh->nh_gw != onh->nh_gw || 264 nh->nh_scope != onh->nh_scope || 265 #ifdef CONFIG_IP_ROUTE_MULTIPATH 266 nh->nh_weight != onh->nh_weight || 267 #endif 268 #ifdef CONFIG_IP_ROUTE_CLASSID 269 nh->nh_tclassid != onh->nh_tclassid || 270 #endif 271 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) || 272 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK)) 273 return -1; 274 onh++; 275 } endfor_nexthops(fi); 276 return 0; 277 } 278 279 static inline unsigned int fib_devindex_hashfn(unsigned int val) 280 { 281 unsigned int mask = DEVINDEX_HASHSIZE - 1; 282 283 return (val ^ 284 (val >> DEVINDEX_HASHBITS) ^ 285 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 286 } 287 288 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 289 { 290 unsigned int mask = (fib_info_hash_size - 1); 291 unsigned int val = fi->fib_nhs; 292 293 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 294 val ^= (__force u32)fi->fib_prefsrc; 295 val ^= fi->fib_priority; 296 for_nexthops(fi) { 297 val ^= fib_devindex_hashfn(nh->nh_oif); 298 } endfor_nexthops(fi) 299 300 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 301 } 302 303 static struct fib_info *fib_find_info(const struct fib_info *nfi) 304 { 305 struct hlist_head *head; 306 struct fib_info *fi; 307 unsigned int hash; 308 309 hash = fib_info_hashfn(nfi); 310 head = &fib_info_hash[hash]; 311 312 hlist_for_each_entry(fi, head, fib_hash) { 313 if (!net_eq(fi->fib_net, nfi->fib_net)) 314 continue; 315 if (fi->fib_nhs != nfi->fib_nhs) 316 continue; 317 if (nfi->fib_protocol == fi->fib_protocol && 318 nfi->fib_scope == fi->fib_scope && 319 nfi->fib_prefsrc == fi->fib_prefsrc && 320 nfi->fib_priority == fi->fib_priority && 321 nfi->fib_type == fi->fib_type && 322 memcmp(nfi->fib_metrics, fi->fib_metrics, 323 sizeof(u32) * RTAX_MAX) == 0 && 324 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 325 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 326 return fi; 327 } 328 329 return NULL; 330 } 331 332 /* Check, that the gateway is already configured. 333 * Used only by redirect accept routine. 334 */ 335 int ip_fib_check_default(__be32 gw, struct net_device *dev) 336 { 337 struct hlist_head *head; 338 struct fib_nh *nh; 339 unsigned int hash; 340 341 spin_lock(&fib_info_lock); 342 343 hash = fib_devindex_hashfn(dev->ifindex); 344 head = &fib_info_devhash[hash]; 345 hlist_for_each_entry(nh, head, nh_hash) { 346 if (nh->nh_dev == dev && 347 nh->nh_gw == gw && 348 !(nh->nh_flags & RTNH_F_DEAD)) { 349 spin_unlock(&fib_info_lock); 350 return 0; 351 } 352 } 353 354 spin_unlock(&fib_info_lock); 355 356 return -1; 357 } 358 359 static inline size_t fib_nlmsg_size(struct fib_info *fi) 360 { 361 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 362 + nla_total_size(4) /* RTA_TABLE */ 363 + nla_total_size(4) /* RTA_DST */ 364 + nla_total_size(4) /* RTA_PRIORITY */ 365 + nla_total_size(4) /* RTA_PREFSRC */ 366 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 367 368 /* space for nested metrics */ 369 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 370 371 if (fi->fib_nhs) { 372 size_t nh_encapsize = 0; 373 /* Also handles the special case fib_nhs == 1 */ 374 375 /* each nexthop is packed in an attribute */ 376 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 377 378 /* may contain flow and gateway attribute */ 379 nhsize += 2 * nla_total_size(4); 380 381 /* grab encap info */ 382 for_nexthops(fi) { 383 if (nh->nh_lwtstate) { 384 /* RTA_ENCAP_TYPE */ 385 nh_encapsize += lwtunnel_get_encap_size( 386 nh->nh_lwtstate); 387 /* RTA_ENCAP */ 388 nh_encapsize += nla_total_size(2); 389 } 390 } endfor_nexthops(fi); 391 392 /* all nexthops are packed in a nested attribute */ 393 payload += nla_total_size((fi->fib_nhs * nhsize) + 394 nh_encapsize); 395 396 } 397 398 return payload; 399 } 400 401 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 402 int dst_len, u32 tb_id, const struct nl_info *info, 403 unsigned int nlm_flags) 404 { 405 struct sk_buff *skb; 406 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 407 int err = -ENOBUFS; 408 409 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 410 if (!skb) 411 goto errout; 412 413 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 414 fa->fa_type, key, dst_len, 415 fa->fa_tos, fa->fa_info, nlm_flags); 416 if (err < 0) { 417 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 418 WARN_ON(err == -EMSGSIZE); 419 kfree_skb(skb); 420 goto errout; 421 } 422 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 423 info->nlh, GFP_KERNEL); 424 return; 425 errout: 426 if (err < 0) 427 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 428 } 429 430 static int fib_detect_death(struct fib_info *fi, int order, 431 struct fib_info **last_resort, int *last_idx, 432 int dflt) 433 { 434 struct neighbour *n; 435 int state = NUD_NONE; 436 437 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); 438 if (n) { 439 state = n->nud_state; 440 neigh_release(n); 441 } else { 442 return 0; 443 } 444 if (state == NUD_REACHABLE) 445 return 0; 446 if ((state & NUD_VALID) && order != dflt) 447 return 0; 448 if ((state & NUD_VALID) || 449 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 450 *last_resort = fi; 451 *last_idx = order; 452 } 453 return 1; 454 } 455 456 #ifdef CONFIG_IP_ROUTE_MULTIPATH 457 458 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining) 459 { 460 int nhs = 0; 461 462 while (rtnh_ok(rtnh, remaining)) { 463 nhs++; 464 rtnh = rtnh_next(rtnh, &remaining); 465 } 466 467 /* leftover implies invalid nexthop configuration, discard it */ 468 return remaining > 0 ? 0 : nhs; 469 } 470 471 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 472 int remaining, struct fib_config *cfg) 473 { 474 int ret; 475 476 change_nexthops(fi) { 477 int attrlen; 478 479 if (!rtnh_ok(rtnh, remaining)) 480 return -EINVAL; 481 482 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 483 return -EINVAL; 484 485 nexthop_nh->nh_flags = 486 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 487 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 488 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 489 490 attrlen = rtnh_attrlen(rtnh); 491 if (attrlen > 0) { 492 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 493 494 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 495 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 496 #ifdef CONFIG_IP_ROUTE_CLASSID 497 nla = nla_find(attrs, attrlen, RTA_FLOW); 498 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 499 if (nexthop_nh->nh_tclassid) 500 fi->fib_net->ipv4.fib_num_tclassid_users++; 501 #endif 502 nla = nla_find(attrs, attrlen, RTA_ENCAP); 503 if (nla) { 504 struct lwtunnel_state *lwtstate; 505 struct nlattr *nla_entype; 506 507 nla_entype = nla_find(attrs, attrlen, 508 RTA_ENCAP_TYPE); 509 if (!nla_entype) 510 goto err_inval; 511 512 ret = lwtunnel_build_state(nla_get_u16( 513 nla_entype), 514 nla, AF_INET, cfg, 515 &lwtstate); 516 if (ret) 517 goto errout; 518 nexthop_nh->nh_lwtstate = 519 lwtstate_get(lwtstate); 520 } 521 } 522 523 rtnh = rtnh_next(rtnh, &remaining); 524 } endfor_nexthops(fi); 525 526 return 0; 527 528 err_inval: 529 ret = -EINVAL; 530 531 errout: 532 return ret; 533 } 534 535 static void fib_rebalance(struct fib_info *fi) 536 { 537 int total; 538 int w; 539 struct in_device *in_dev; 540 541 if (fi->fib_nhs < 2) 542 return; 543 544 total = 0; 545 for_nexthops(fi) { 546 if (nh->nh_flags & RTNH_F_DEAD) 547 continue; 548 549 in_dev = __in_dev_get_rtnl(nh->nh_dev); 550 551 if (in_dev && 552 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 553 nh->nh_flags & RTNH_F_LINKDOWN) 554 continue; 555 556 total += nh->nh_weight; 557 } endfor_nexthops(fi); 558 559 w = 0; 560 change_nexthops(fi) { 561 int upper_bound; 562 563 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev); 564 565 if (nexthop_nh->nh_flags & RTNH_F_DEAD) { 566 upper_bound = -1; 567 } else if (in_dev && 568 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 569 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) { 570 upper_bound = -1; 571 } else { 572 w += nexthop_nh->nh_weight; 573 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 574 total) - 1; 575 } 576 577 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound); 578 } endfor_nexthops(fi); 579 580 net_get_random_once(&fib_multipath_secret, 581 sizeof(fib_multipath_secret)); 582 } 583 584 static inline void fib_add_weight(struct fib_info *fi, 585 const struct fib_nh *nh) 586 { 587 fi->fib_weight += nh->nh_weight; 588 } 589 590 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 591 592 #define fib_rebalance(fi) do { } while (0) 593 #define fib_add_weight(fi, nh) do { } while (0) 594 595 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 596 597 static int fib_encap_match(u16 encap_type, 598 struct nlattr *encap, 599 const struct fib_nh *nh, 600 const struct fib_config *cfg) 601 { 602 struct lwtunnel_state *lwtstate; 603 int ret, result = 0; 604 605 if (encap_type == LWTUNNEL_ENCAP_NONE) 606 return 0; 607 608 ret = lwtunnel_build_state(encap_type, encap, 609 AF_INET, cfg, &lwtstate); 610 if (!ret) { 611 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 612 lwtstate_free(lwtstate); 613 } 614 615 return result; 616 } 617 618 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 619 { 620 #ifdef CONFIG_IP_ROUTE_MULTIPATH 621 struct rtnexthop *rtnh; 622 int remaining; 623 #endif 624 625 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 626 return 1; 627 628 if (cfg->fc_oif || cfg->fc_gw) { 629 if (cfg->fc_encap) { 630 if (fib_encap_match(cfg->fc_encap_type, 631 cfg->fc_encap, fi->fib_nh, cfg)) 632 return 1; 633 } 634 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 635 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 636 return 0; 637 return 1; 638 } 639 640 #ifdef CONFIG_IP_ROUTE_MULTIPATH 641 if (!cfg->fc_mp) 642 return 0; 643 644 rtnh = cfg->fc_mp; 645 remaining = cfg->fc_mp_len; 646 647 for_nexthops(fi) { 648 int attrlen; 649 650 if (!rtnh_ok(rtnh, remaining)) 651 return -EINVAL; 652 653 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 654 return 1; 655 656 attrlen = rtnh_attrlen(rtnh); 657 if (attrlen > 0) { 658 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 659 660 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 661 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 662 return 1; 663 #ifdef CONFIG_IP_ROUTE_CLASSID 664 nla = nla_find(attrs, attrlen, RTA_FLOW); 665 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 666 return 1; 667 #endif 668 } 669 670 rtnh = rtnh_next(rtnh, &remaining); 671 } endfor_nexthops(fi); 672 #endif 673 return 0; 674 } 675 676 677 /* 678 * Picture 679 * ------- 680 * 681 * Semantics of nexthop is very messy by historical reasons. 682 * We have to take into account, that: 683 * a) gateway can be actually local interface address, 684 * so that gatewayed route is direct. 685 * b) gateway must be on-link address, possibly 686 * described not by an ifaddr, but also by a direct route. 687 * c) If both gateway and interface are specified, they should not 688 * contradict. 689 * d) If we use tunnel routes, gateway could be not on-link. 690 * 691 * Attempt to reconcile all of these (alas, self-contradictory) conditions 692 * results in pretty ugly and hairy code with obscure logic. 693 * 694 * I chose to generalized it instead, so that the size 695 * of code does not increase practically, but it becomes 696 * much more general. 697 * Every prefix is assigned a "scope" value: "host" is local address, 698 * "link" is direct route, 699 * [ ... "site" ... "interior" ... ] 700 * and "universe" is true gateway route with global meaning. 701 * 702 * Every prefix refers to a set of "nexthop"s (gw, oif), 703 * where gw must have narrower scope. This recursion stops 704 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 705 * which means that gw is forced to be on link. 706 * 707 * Code is still hairy, but now it is apparently logically 708 * consistent and very flexible. F.e. as by-product it allows 709 * to co-exists in peace independent exterior and interior 710 * routing processes. 711 * 712 * Normally it looks as following. 713 * 714 * {universe prefix} -> (gw, oif) [scope link] 715 * | 716 * |-> {link prefix} -> (gw, oif) [scope local] 717 * | 718 * |-> {local prefix} (terminal node) 719 */ 720 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 721 struct fib_nh *nh) 722 { 723 int err = 0; 724 struct net *net; 725 struct net_device *dev; 726 727 net = cfg->fc_nlinfo.nl_net; 728 if (nh->nh_gw) { 729 struct fib_result res; 730 731 if (nh->nh_flags & RTNH_F_ONLINK) { 732 unsigned int addr_type; 733 734 if (cfg->fc_scope >= RT_SCOPE_LINK) 735 return -EINVAL; 736 dev = __dev_get_by_index(net, nh->nh_oif); 737 if (!dev) 738 return -ENODEV; 739 if (!(dev->flags & IFF_UP)) 740 return -ENETDOWN; 741 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 742 if (addr_type != RTN_UNICAST) 743 return -EINVAL; 744 if (!netif_carrier_ok(dev)) 745 nh->nh_flags |= RTNH_F_LINKDOWN; 746 nh->nh_dev = dev; 747 dev_hold(dev); 748 nh->nh_scope = RT_SCOPE_LINK; 749 return 0; 750 } 751 rcu_read_lock(); 752 { 753 struct fib_table *tbl = NULL; 754 struct flowi4 fl4 = { 755 .daddr = nh->nh_gw, 756 .flowi4_scope = cfg->fc_scope + 1, 757 .flowi4_oif = nh->nh_oif, 758 .flowi4_iif = LOOPBACK_IFINDEX, 759 }; 760 761 /* It is not necessary, but requires a bit of thinking */ 762 if (fl4.flowi4_scope < RT_SCOPE_LINK) 763 fl4.flowi4_scope = RT_SCOPE_LINK; 764 765 if (cfg->fc_table) 766 tbl = fib_get_table(net, cfg->fc_table); 767 768 if (tbl) 769 err = fib_table_lookup(tbl, &fl4, &res, 770 FIB_LOOKUP_IGNORE_LINKSTATE | 771 FIB_LOOKUP_NOREF); 772 773 /* on error or if no table given do full lookup. This 774 * is needed for example when nexthops are in the local 775 * table rather than the given table 776 */ 777 if (!tbl || err) { 778 err = fib_lookup(net, &fl4, &res, 779 FIB_LOOKUP_IGNORE_LINKSTATE); 780 } 781 782 if (err) { 783 rcu_read_unlock(); 784 return err; 785 } 786 } 787 err = -EINVAL; 788 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 789 goto out; 790 nh->nh_scope = res.scope; 791 nh->nh_oif = FIB_RES_OIF(res); 792 nh->nh_dev = dev = FIB_RES_DEV(res); 793 if (!dev) 794 goto out; 795 dev_hold(dev); 796 if (!netif_carrier_ok(dev)) 797 nh->nh_flags |= RTNH_F_LINKDOWN; 798 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 799 } else { 800 struct in_device *in_dev; 801 802 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 803 return -EINVAL; 804 805 rcu_read_lock(); 806 err = -ENODEV; 807 in_dev = inetdev_by_index(net, nh->nh_oif); 808 if (!in_dev) 809 goto out; 810 err = -ENETDOWN; 811 if (!(in_dev->dev->flags & IFF_UP)) 812 goto out; 813 nh->nh_dev = in_dev->dev; 814 dev_hold(nh->nh_dev); 815 nh->nh_scope = RT_SCOPE_HOST; 816 if (!netif_carrier_ok(nh->nh_dev)) 817 nh->nh_flags |= RTNH_F_LINKDOWN; 818 err = 0; 819 } 820 out: 821 rcu_read_unlock(); 822 return err; 823 } 824 825 static inline unsigned int fib_laddr_hashfn(__be32 val) 826 { 827 unsigned int mask = (fib_info_hash_size - 1); 828 829 return ((__force u32)val ^ 830 ((__force u32)val >> 7) ^ 831 ((__force u32)val >> 14)) & mask; 832 } 833 834 static struct hlist_head *fib_info_hash_alloc(int bytes) 835 { 836 if (bytes <= PAGE_SIZE) 837 return kzalloc(bytes, GFP_KERNEL); 838 else 839 return (struct hlist_head *) 840 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 841 get_order(bytes)); 842 } 843 844 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 845 { 846 if (!hash) 847 return; 848 849 if (bytes <= PAGE_SIZE) 850 kfree(hash); 851 else 852 free_pages((unsigned long) hash, get_order(bytes)); 853 } 854 855 static void fib_info_hash_move(struct hlist_head *new_info_hash, 856 struct hlist_head *new_laddrhash, 857 unsigned int new_size) 858 { 859 struct hlist_head *old_info_hash, *old_laddrhash; 860 unsigned int old_size = fib_info_hash_size; 861 unsigned int i, bytes; 862 863 spin_lock_bh(&fib_info_lock); 864 old_info_hash = fib_info_hash; 865 old_laddrhash = fib_info_laddrhash; 866 fib_info_hash_size = new_size; 867 868 for (i = 0; i < old_size; i++) { 869 struct hlist_head *head = &fib_info_hash[i]; 870 struct hlist_node *n; 871 struct fib_info *fi; 872 873 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 874 struct hlist_head *dest; 875 unsigned int new_hash; 876 877 new_hash = fib_info_hashfn(fi); 878 dest = &new_info_hash[new_hash]; 879 hlist_add_head(&fi->fib_hash, dest); 880 } 881 } 882 fib_info_hash = new_info_hash; 883 884 for (i = 0; i < old_size; i++) { 885 struct hlist_head *lhead = &fib_info_laddrhash[i]; 886 struct hlist_node *n; 887 struct fib_info *fi; 888 889 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 890 struct hlist_head *ldest; 891 unsigned int new_hash; 892 893 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 894 ldest = &new_laddrhash[new_hash]; 895 hlist_add_head(&fi->fib_lhash, ldest); 896 } 897 } 898 fib_info_laddrhash = new_laddrhash; 899 900 spin_unlock_bh(&fib_info_lock); 901 902 bytes = old_size * sizeof(struct hlist_head *); 903 fib_info_hash_free(old_info_hash, bytes); 904 fib_info_hash_free(old_laddrhash, bytes); 905 } 906 907 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 908 { 909 nh->nh_saddr = inet_select_addr(nh->nh_dev, 910 nh->nh_gw, 911 nh->nh_parent->fib_scope); 912 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 913 914 return nh->nh_saddr; 915 } 916 917 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 918 { 919 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 920 fib_prefsrc != cfg->fc_dst) { 921 u32 tb_id = cfg->fc_table; 922 int rc; 923 924 if (tb_id == RT_TABLE_MAIN) 925 tb_id = RT_TABLE_LOCAL; 926 927 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 928 fib_prefsrc, tb_id); 929 930 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 931 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 932 fib_prefsrc, RT_TABLE_LOCAL); 933 } 934 935 if (rc != RTN_LOCAL) 936 return false; 937 } 938 return true; 939 } 940 941 static int 942 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 943 { 944 bool ecn_ca = false; 945 struct nlattr *nla; 946 int remaining; 947 948 if (!cfg->fc_mx) 949 return 0; 950 951 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 952 int type = nla_type(nla); 953 u32 val; 954 955 if (!type) 956 continue; 957 if (type > RTAX_MAX) 958 return -EINVAL; 959 960 if (type == RTAX_CC_ALGO) { 961 char tmp[TCP_CA_NAME_MAX]; 962 963 nla_strlcpy(tmp, nla, sizeof(tmp)); 964 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 965 if (val == TCP_CA_UNSPEC) 966 return -EINVAL; 967 } else { 968 val = nla_get_u32(nla); 969 } 970 if (type == RTAX_ADVMSS && val > 65535 - 40) 971 val = 65535 - 40; 972 if (type == RTAX_MTU && val > 65535 - 15) 973 val = 65535 - 15; 974 if (type == RTAX_HOPLIMIT && val > 255) 975 val = 255; 976 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 977 return -EINVAL; 978 fi->fib_metrics[type - 1] = val; 979 } 980 981 if (ecn_ca) 982 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 983 984 return 0; 985 } 986 987 struct fib_info *fib_create_info(struct fib_config *cfg) 988 { 989 int err; 990 struct fib_info *fi = NULL; 991 struct fib_info *ofi; 992 int nhs = 1; 993 struct net *net = cfg->fc_nlinfo.nl_net; 994 995 if (cfg->fc_type > RTN_MAX) 996 goto err_inval; 997 998 /* Fast check to catch the most weird cases */ 999 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 1000 goto err_inval; 1001 1002 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 1003 goto err_inval; 1004 1005 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1006 if (cfg->fc_mp) { 1007 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 1008 if (nhs == 0) 1009 goto err_inval; 1010 } 1011 #endif 1012 1013 err = -ENOBUFS; 1014 if (fib_info_cnt >= fib_info_hash_size) { 1015 unsigned int new_size = fib_info_hash_size << 1; 1016 struct hlist_head *new_info_hash; 1017 struct hlist_head *new_laddrhash; 1018 unsigned int bytes; 1019 1020 if (!new_size) 1021 new_size = 16; 1022 bytes = new_size * sizeof(struct hlist_head *); 1023 new_info_hash = fib_info_hash_alloc(bytes); 1024 new_laddrhash = fib_info_hash_alloc(bytes); 1025 if (!new_info_hash || !new_laddrhash) { 1026 fib_info_hash_free(new_info_hash, bytes); 1027 fib_info_hash_free(new_laddrhash, bytes); 1028 } else 1029 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1030 1031 if (!fib_info_hash_size) 1032 goto failure; 1033 } 1034 1035 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1036 if (!fi) 1037 goto failure; 1038 fib_info_cnt++; 1039 if (cfg->fc_mx) { 1040 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 1041 if (!fi->fib_metrics) 1042 goto failure; 1043 } else 1044 fi->fib_metrics = (u32 *) dst_default_metrics; 1045 1046 fi->fib_net = net; 1047 fi->fib_protocol = cfg->fc_protocol; 1048 fi->fib_scope = cfg->fc_scope; 1049 fi->fib_flags = cfg->fc_flags; 1050 fi->fib_priority = cfg->fc_priority; 1051 fi->fib_prefsrc = cfg->fc_prefsrc; 1052 fi->fib_type = cfg->fc_type; 1053 fi->fib_tb_id = cfg->fc_table; 1054 1055 fi->fib_nhs = nhs; 1056 change_nexthops(fi) { 1057 nexthop_nh->nh_parent = fi; 1058 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1059 if (!nexthop_nh->nh_pcpu_rth_output) 1060 goto failure; 1061 } endfor_nexthops(fi) 1062 1063 err = fib_convert_metrics(fi, cfg); 1064 if (err) 1065 goto failure; 1066 1067 if (cfg->fc_mp) { 1068 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1069 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 1070 if (err != 0) 1071 goto failure; 1072 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 1073 goto err_inval; 1074 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 1075 goto err_inval; 1076 #ifdef CONFIG_IP_ROUTE_CLASSID 1077 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 1078 goto err_inval; 1079 #endif 1080 #else 1081 goto err_inval; 1082 #endif 1083 } else { 1084 struct fib_nh *nh = fi->fib_nh; 1085 1086 if (cfg->fc_encap) { 1087 struct lwtunnel_state *lwtstate; 1088 1089 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) 1090 goto err_inval; 1091 err = lwtunnel_build_state(cfg->fc_encap_type, 1092 cfg->fc_encap, AF_INET, cfg, 1093 &lwtstate); 1094 if (err) 1095 goto failure; 1096 1097 nh->nh_lwtstate = lwtstate_get(lwtstate); 1098 } 1099 nh->nh_oif = cfg->fc_oif; 1100 nh->nh_gw = cfg->fc_gw; 1101 nh->nh_flags = cfg->fc_flags; 1102 #ifdef CONFIG_IP_ROUTE_CLASSID 1103 nh->nh_tclassid = cfg->fc_flow; 1104 if (nh->nh_tclassid) 1105 fi->fib_net->ipv4.fib_num_tclassid_users++; 1106 #endif 1107 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1108 nh->nh_weight = 1; 1109 #endif 1110 } 1111 1112 if (fib_props[cfg->fc_type].error) { 1113 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 1114 goto err_inval; 1115 goto link_it; 1116 } else { 1117 switch (cfg->fc_type) { 1118 case RTN_UNICAST: 1119 case RTN_LOCAL: 1120 case RTN_BROADCAST: 1121 case RTN_ANYCAST: 1122 case RTN_MULTICAST: 1123 break; 1124 default: 1125 goto err_inval; 1126 } 1127 } 1128 1129 if (cfg->fc_scope > RT_SCOPE_HOST) 1130 goto err_inval; 1131 1132 if (cfg->fc_scope == RT_SCOPE_HOST) { 1133 struct fib_nh *nh = fi->fib_nh; 1134 1135 /* Local address is added. */ 1136 if (nhs != 1 || nh->nh_gw) 1137 goto err_inval; 1138 nh->nh_scope = RT_SCOPE_NOWHERE; 1139 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1140 err = -ENODEV; 1141 if (!nh->nh_dev) 1142 goto failure; 1143 } else { 1144 int linkdown = 0; 1145 1146 change_nexthops(fi) { 1147 err = fib_check_nh(cfg, fi, nexthop_nh); 1148 if (err != 0) 1149 goto failure; 1150 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1151 linkdown++; 1152 } endfor_nexthops(fi) 1153 if (linkdown == fi->fib_nhs) 1154 fi->fib_flags |= RTNH_F_LINKDOWN; 1155 } 1156 1157 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) 1158 goto err_inval; 1159 1160 change_nexthops(fi) { 1161 fib_info_update_nh_saddr(net, nexthop_nh); 1162 fib_add_weight(fi, nexthop_nh); 1163 } endfor_nexthops(fi) 1164 1165 fib_rebalance(fi); 1166 1167 link_it: 1168 ofi = fib_find_info(fi); 1169 if (ofi) { 1170 fi->fib_dead = 1; 1171 free_fib_info(fi); 1172 ofi->fib_treeref++; 1173 return ofi; 1174 } 1175 1176 fi->fib_treeref++; 1177 atomic_inc(&fi->fib_clntref); 1178 spin_lock_bh(&fib_info_lock); 1179 hlist_add_head(&fi->fib_hash, 1180 &fib_info_hash[fib_info_hashfn(fi)]); 1181 if (fi->fib_prefsrc) { 1182 struct hlist_head *head; 1183 1184 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1185 hlist_add_head(&fi->fib_lhash, head); 1186 } 1187 change_nexthops(fi) { 1188 struct hlist_head *head; 1189 unsigned int hash; 1190 1191 if (!nexthop_nh->nh_dev) 1192 continue; 1193 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1194 head = &fib_info_devhash[hash]; 1195 hlist_add_head(&nexthop_nh->nh_hash, head); 1196 } endfor_nexthops(fi) 1197 spin_unlock_bh(&fib_info_lock); 1198 return fi; 1199 1200 err_inval: 1201 err = -EINVAL; 1202 1203 failure: 1204 if (fi) { 1205 fi->fib_dead = 1; 1206 free_fib_info(fi); 1207 } 1208 1209 return ERR_PTR(err); 1210 } 1211 1212 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1213 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1214 struct fib_info *fi, unsigned int flags) 1215 { 1216 struct nlmsghdr *nlh; 1217 struct rtmsg *rtm; 1218 1219 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1220 if (!nlh) 1221 return -EMSGSIZE; 1222 1223 rtm = nlmsg_data(nlh); 1224 rtm->rtm_family = AF_INET; 1225 rtm->rtm_dst_len = dst_len; 1226 rtm->rtm_src_len = 0; 1227 rtm->rtm_tos = tos; 1228 if (tb_id < 256) 1229 rtm->rtm_table = tb_id; 1230 else 1231 rtm->rtm_table = RT_TABLE_COMPAT; 1232 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1233 goto nla_put_failure; 1234 rtm->rtm_type = type; 1235 rtm->rtm_flags = fi->fib_flags; 1236 rtm->rtm_scope = fi->fib_scope; 1237 rtm->rtm_protocol = fi->fib_protocol; 1238 1239 if (rtm->rtm_dst_len && 1240 nla_put_in_addr(skb, RTA_DST, dst)) 1241 goto nla_put_failure; 1242 if (fi->fib_priority && 1243 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1244 goto nla_put_failure; 1245 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1246 goto nla_put_failure; 1247 1248 if (fi->fib_prefsrc && 1249 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1250 goto nla_put_failure; 1251 if (fi->fib_nhs == 1) { 1252 struct in_device *in_dev; 1253 1254 if (fi->fib_nh->nh_gw && 1255 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1256 goto nla_put_failure; 1257 if (fi->fib_nh->nh_oif && 1258 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1259 goto nla_put_failure; 1260 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1261 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1262 if (in_dev && 1263 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1264 rtm->rtm_flags |= RTNH_F_DEAD; 1265 } 1266 #ifdef CONFIG_IP_ROUTE_CLASSID 1267 if (fi->fib_nh[0].nh_tclassid && 1268 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1269 goto nla_put_failure; 1270 #endif 1271 if (fi->fib_nh->nh_lwtstate && 1272 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0) 1273 goto nla_put_failure; 1274 } 1275 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1276 if (fi->fib_nhs > 1) { 1277 struct rtnexthop *rtnh; 1278 struct nlattr *mp; 1279 1280 mp = nla_nest_start(skb, RTA_MULTIPATH); 1281 if (!mp) 1282 goto nla_put_failure; 1283 1284 for_nexthops(fi) { 1285 struct in_device *in_dev; 1286 1287 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1288 if (!rtnh) 1289 goto nla_put_failure; 1290 1291 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1292 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1293 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1294 if (in_dev && 1295 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1296 rtnh->rtnh_flags |= RTNH_F_DEAD; 1297 } 1298 rtnh->rtnh_hops = nh->nh_weight - 1; 1299 rtnh->rtnh_ifindex = nh->nh_oif; 1300 1301 if (nh->nh_gw && 1302 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1303 goto nla_put_failure; 1304 #ifdef CONFIG_IP_ROUTE_CLASSID 1305 if (nh->nh_tclassid && 1306 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1307 goto nla_put_failure; 1308 #endif 1309 if (nh->nh_lwtstate && 1310 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0) 1311 goto nla_put_failure; 1312 1313 /* length of rtnetlink header + attributes */ 1314 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1315 } endfor_nexthops(fi); 1316 1317 nla_nest_end(skb, mp); 1318 } 1319 #endif 1320 nlmsg_end(skb, nlh); 1321 return 0; 1322 1323 nla_put_failure: 1324 nlmsg_cancel(skb, nlh); 1325 return -EMSGSIZE; 1326 } 1327 1328 /* 1329 * Update FIB if: 1330 * - local address disappeared -> we must delete all the entries 1331 * referring to it. 1332 * - device went down -> we must shutdown all nexthops going via it. 1333 */ 1334 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1335 { 1336 int ret = 0; 1337 unsigned int hash = fib_laddr_hashfn(local); 1338 struct hlist_head *head = &fib_info_laddrhash[hash]; 1339 struct net *net = dev_net(dev); 1340 int tb_id = l3mdev_fib_table(dev); 1341 struct fib_info *fi; 1342 1343 if (!fib_info_laddrhash || local == 0) 1344 return 0; 1345 1346 hlist_for_each_entry(fi, head, fib_lhash) { 1347 if (!net_eq(fi->fib_net, net) || 1348 fi->fib_tb_id != tb_id) 1349 continue; 1350 if (fi->fib_prefsrc == local) { 1351 fi->fib_flags |= RTNH_F_DEAD; 1352 ret++; 1353 } 1354 } 1355 return ret; 1356 } 1357 1358 /* Event force Flags Description 1359 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1360 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1361 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1362 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1363 */ 1364 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1365 { 1366 int ret = 0; 1367 int scope = RT_SCOPE_NOWHERE; 1368 struct fib_info *prev_fi = NULL; 1369 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1370 struct hlist_head *head = &fib_info_devhash[hash]; 1371 struct fib_nh *nh; 1372 1373 if (force) 1374 scope = -1; 1375 1376 hlist_for_each_entry(nh, head, nh_hash) { 1377 struct fib_info *fi = nh->nh_parent; 1378 int dead; 1379 1380 BUG_ON(!fi->fib_nhs); 1381 if (nh->nh_dev != dev || fi == prev_fi) 1382 continue; 1383 prev_fi = fi; 1384 dead = 0; 1385 change_nexthops(fi) { 1386 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1387 dead++; 1388 else if (nexthop_nh->nh_dev == dev && 1389 nexthop_nh->nh_scope != scope) { 1390 switch (event) { 1391 case NETDEV_DOWN: 1392 case NETDEV_UNREGISTER: 1393 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1394 /* fall through */ 1395 case NETDEV_CHANGE: 1396 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1397 break; 1398 } 1399 dead++; 1400 } 1401 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1402 if (event == NETDEV_UNREGISTER && 1403 nexthop_nh->nh_dev == dev) { 1404 dead = fi->fib_nhs; 1405 break; 1406 } 1407 #endif 1408 } endfor_nexthops(fi) 1409 if (dead == fi->fib_nhs) { 1410 switch (event) { 1411 case NETDEV_DOWN: 1412 case NETDEV_UNREGISTER: 1413 fi->fib_flags |= RTNH_F_DEAD; 1414 /* fall through */ 1415 case NETDEV_CHANGE: 1416 fi->fib_flags |= RTNH_F_LINKDOWN; 1417 break; 1418 } 1419 ret++; 1420 } 1421 1422 fib_rebalance(fi); 1423 } 1424 1425 return ret; 1426 } 1427 1428 /* Must be invoked inside of an RCU protected region. */ 1429 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1430 { 1431 struct fib_info *fi = NULL, *last_resort = NULL; 1432 struct hlist_head *fa_head = res->fa_head; 1433 struct fib_table *tb = res->table; 1434 u8 slen = 32 - res->prefixlen; 1435 int order = -1, last_idx = -1; 1436 struct fib_alias *fa, *fa1 = NULL; 1437 u32 last_prio = res->fi->fib_priority; 1438 u8 last_tos = 0; 1439 1440 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1441 struct fib_info *next_fi = fa->fa_info; 1442 1443 if (fa->fa_slen != slen) 1444 continue; 1445 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1446 continue; 1447 if (fa->tb_id != tb->tb_id) 1448 continue; 1449 if (next_fi->fib_priority > last_prio && 1450 fa->fa_tos == last_tos) { 1451 if (last_tos) 1452 continue; 1453 break; 1454 } 1455 if (next_fi->fib_flags & RTNH_F_DEAD) 1456 continue; 1457 last_tos = fa->fa_tos; 1458 last_prio = next_fi->fib_priority; 1459 1460 if (next_fi->fib_scope != res->scope || 1461 fa->fa_type != RTN_UNICAST) 1462 continue; 1463 if (!next_fi->fib_nh[0].nh_gw || 1464 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1465 continue; 1466 1467 fib_alias_accessed(fa); 1468 1469 if (!fi) { 1470 if (next_fi != res->fi) 1471 break; 1472 fa1 = fa; 1473 } else if (!fib_detect_death(fi, order, &last_resort, 1474 &last_idx, fa1->fa_default)) { 1475 fib_result_assign(res, fi); 1476 fa1->fa_default = order; 1477 goto out; 1478 } 1479 fi = next_fi; 1480 order++; 1481 } 1482 1483 if (order <= 0 || !fi) { 1484 if (fa1) 1485 fa1->fa_default = -1; 1486 goto out; 1487 } 1488 1489 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1490 fa1->fa_default)) { 1491 fib_result_assign(res, fi); 1492 fa1->fa_default = order; 1493 goto out; 1494 } 1495 1496 if (last_idx >= 0) 1497 fib_result_assign(res, last_resort); 1498 fa1->fa_default = last_idx; 1499 out: 1500 return; 1501 } 1502 1503 /* 1504 * Dead device goes up. We wake up dead nexthops. 1505 * It takes sense only on multipath routes. 1506 */ 1507 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1508 { 1509 struct fib_info *prev_fi; 1510 unsigned int hash; 1511 struct hlist_head *head; 1512 struct fib_nh *nh; 1513 int ret; 1514 1515 if (!(dev->flags & IFF_UP)) 1516 return 0; 1517 1518 if (nh_flags & RTNH_F_DEAD) { 1519 unsigned int flags = dev_get_flags(dev); 1520 1521 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1522 nh_flags |= RTNH_F_LINKDOWN; 1523 } 1524 1525 prev_fi = NULL; 1526 hash = fib_devindex_hashfn(dev->ifindex); 1527 head = &fib_info_devhash[hash]; 1528 ret = 0; 1529 1530 hlist_for_each_entry(nh, head, nh_hash) { 1531 struct fib_info *fi = nh->nh_parent; 1532 int alive; 1533 1534 BUG_ON(!fi->fib_nhs); 1535 if (nh->nh_dev != dev || fi == prev_fi) 1536 continue; 1537 1538 prev_fi = fi; 1539 alive = 0; 1540 change_nexthops(fi) { 1541 if (!(nexthop_nh->nh_flags & nh_flags)) { 1542 alive++; 1543 continue; 1544 } 1545 if (!nexthop_nh->nh_dev || 1546 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1547 continue; 1548 if (nexthop_nh->nh_dev != dev || 1549 !__in_dev_get_rtnl(dev)) 1550 continue; 1551 alive++; 1552 nexthop_nh->nh_flags &= ~nh_flags; 1553 } endfor_nexthops(fi) 1554 1555 if (alive > 0) { 1556 fi->fib_flags &= ~nh_flags; 1557 ret++; 1558 } 1559 1560 fib_rebalance(fi); 1561 } 1562 1563 return ret; 1564 } 1565 1566 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1567 static bool fib_good_nh(const struct fib_nh *nh) 1568 { 1569 int state = NUD_REACHABLE; 1570 1571 if (nh->nh_scope == RT_SCOPE_LINK) { 1572 struct neighbour *n; 1573 1574 rcu_read_lock_bh(); 1575 1576 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1577 (__force u32)nh->nh_gw); 1578 if (n) 1579 state = n->nud_state; 1580 1581 rcu_read_unlock_bh(); 1582 } 1583 1584 return !!(state & NUD_VALID); 1585 } 1586 1587 void fib_select_multipath(struct fib_result *res, int hash) 1588 { 1589 struct fib_info *fi = res->fi; 1590 struct net *net = fi->fib_net; 1591 bool first = false; 1592 1593 for_nexthops(fi) { 1594 if (hash > atomic_read(&nh->nh_upper_bound)) 1595 continue; 1596 1597 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1598 fib_good_nh(nh)) { 1599 res->nh_sel = nhsel; 1600 return; 1601 } 1602 if (!first) { 1603 res->nh_sel = nhsel; 1604 first = true; 1605 } 1606 } endfor_nexthops(fi); 1607 } 1608 #endif 1609 1610 void fib_select_path(struct net *net, struct fib_result *res, 1611 struct flowi4 *fl4, int mp_hash) 1612 { 1613 bool oif_check; 1614 1615 oif_check = (fl4->flowi4_oif == 0 || 1616 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF); 1617 1618 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1619 if (res->fi->fib_nhs > 1 && oif_check) { 1620 if (mp_hash < 0) 1621 mp_hash = get_hash_from_flowi4(fl4) >> 1; 1622 1623 fib_select_multipath(res, mp_hash); 1624 } 1625 else 1626 #endif 1627 if (!res->prefixlen && 1628 res->table->tb_num_default > 1 && 1629 res->type == RTN_UNICAST && oif_check) 1630 fib_select_default(fl4, res); 1631 1632 if (!fl4->saddr) 1633 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1634 } 1635 EXPORT_SYMBOL_GPL(fib_select_path); 1636