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