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 <asm/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 static DEFINE_SPINLOCK(fib_multipath_lock); 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_free(&rt->dst); 157 } 158 159 static void free_nh_exceptions(struct fib_nh *nh) 160 { 161 struct fnhe_hash_bucket *hash; 162 int i; 163 164 hash = rcu_dereference_protected(nh->nh_exceptions, 1); 165 if (!hash) 166 return; 167 for (i = 0; i < FNHE_HASH_SIZE; i++) { 168 struct fib_nh_exception *fnhe; 169 170 fnhe = rcu_dereference_protected(hash[i].chain, 1); 171 while (fnhe) { 172 struct fib_nh_exception *next; 173 174 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 175 176 rt_fibinfo_free(&fnhe->fnhe_rth_input); 177 rt_fibinfo_free(&fnhe->fnhe_rth_output); 178 179 kfree(fnhe); 180 181 fnhe = next; 182 } 183 } 184 kfree(hash); 185 } 186 187 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 188 { 189 int cpu; 190 191 if (!rtp) 192 return; 193 194 for_each_possible_cpu(cpu) { 195 struct rtable *rt; 196 197 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 198 if (rt) 199 dst_free(&rt->dst); 200 } 201 free_percpu(rtp); 202 } 203 204 /* Release a nexthop info record */ 205 static void free_fib_info_rcu(struct rcu_head *head) 206 { 207 struct fib_info *fi = container_of(head, struct fib_info, rcu); 208 209 change_nexthops(fi) { 210 if (nexthop_nh->nh_dev) 211 dev_put(nexthop_nh->nh_dev); 212 lwtstate_put(nexthop_nh->nh_lwtstate); 213 free_nh_exceptions(nexthop_nh); 214 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 215 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 216 } endfor_nexthops(fi); 217 218 if (fi->fib_metrics != (u32 *) dst_default_metrics) 219 kfree(fi->fib_metrics); 220 kfree(fi); 221 } 222 223 void free_fib_info(struct fib_info *fi) 224 { 225 if (fi->fib_dead == 0) { 226 pr_warn("Freeing alive fib_info %p\n", fi); 227 return; 228 } 229 fib_info_cnt--; 230 #ifdef CONFIG_IP_ROUTE_CLASSID 231 change_nexthops(fi) { 232 if (nexthop_nh->nh_tclassid) 233 fi->fib_net->ipv4.fib_num_tclassid_users--; 234 } endfor_nexthops(fi); 235 #endif 236 call_rcu(&fi->rcu, free_fib_info_rcu); 237 } 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 struct net *net = cfg->fc_nlinfo.nl_net; 475 int ret; 476 477 change_nexthops(fi) { 478 int attrlen; 479 480 if (!rtnh_ok(rtnh, remaining)) 481 return -EINVAL; 482 483 nexthop_nh->nh_flags = 484 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 485 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 486 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 487 488 attrlen = rtnh_attrlen(rtnh); 489 if (attrlen > 0) { 490 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 491 492 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 493 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 494 #ifdef CONFIG_IP_ROUTE_CLASSID 495 nla = nla_find(attrs, attrlen, RTA_FLOW); 496 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 497 if (nexthop_nh->nh_tclassid) 498 fi->fib_net->ipv4.fib_num_tclassid_users++; 499 #endif 500 nla = nla_find(attrs, attrlen, RTA_ENCAP); 501 if (nla) { 502 struct lwtunnel_state *lwtstate; 503 struct net_device *dev = NULL; 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 if (cfg->fc_oif) 511 dev = __dev_get_by_index(net, cfg->fc_oif); 512 ret = lwtunnel_build_state(dev, nla_get_u16( 513 nla_entype), 514 nla, &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 #endif 535 536 int fib_encap_match(struct net *net, u16 encap_type, 537 struct nlattr *encap, 538 int oif, const struct fib_nh *nh) 539 { 540 struct lwtunnel_state *lwtstate; 541 struct net_device *dev = NULL; 542 int ret; 543 544 if (encap_type == LWTUNNEL_ENCAP_NONE) 545 return 0; 546 547 if (oif) 548 dev = __dev_get_by_index(net, oif); 549 ret = lwtunnel_build_state(dev, encap_type, 550 encap, &lwtstate); 551 if (!ret) 552 return lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 553 554 return 0; 555 } 556 557 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 558 { 559 struct net *net = cfg->fc_nlinfo.nl_net; 560 #ifdef CONFIG_IP_ROUTE_MULTIPATH 561 struct rtnexthop *rtnh; 562 int remaining; 563 #endif 564 565 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 566 return 1; 567 568 if (cfg->fc_oif || cfg->fc_gw) { 569 if (cfg->fc_encap) { 570 if (fib_encap_match(net, cfg->fc_encap_type, 571 cfg->fc_encap, cfg->fc_oif, 572 fi->fib_nh)) 573 return 1; 574 } 575 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 576 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 577 return 0; 578 return 1; 579 } 580 581 #ifdef CONFIG_IP_ROUTE_MULTIPATH 582 if (!cfg->fc_mp) 583 return 0; 584 585 rtnh = cfg->fc_mp; 586 remaining = cfg->fc_mp_len; 587 588 for_nexthops(fi) { 589 int attrlen; 590 591 if (!rtnh_ok(rtnh, remaining)) 592 return -EINVAL; 593 594 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 595 return 1; 596 597 attrlen = rtnh_attrlen(rtnh); 598 if (attrlen > 0) { 599 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 600 601 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 602 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 603 return 1; 604 #ifdef CONFIG_IP_ROUTE_CLASSID 605 nla = nla_find(attrs, attrlen, RTA_FLOW); 606 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 607 return 1; 608 #endif 609 } 610 611 rtnh = rtnh_next(rtnh, &remaining); 612 } endfor_nexthops(fi); 613 #endif 614 return 0; 615 } 616 617 618 /* 619 * Picture 620 * ------- 621 * 622 * Semantics of nexthop is very messy by historical reasons. 623 * We have to take into account, that: 624 * a) gateway can be actually local interface address, 625 * so that gatewayed route is direct. 626 * b) gateway must be on-link address, possibly 627 * described not by an ifaddr, but also by a direct route. 628 * c) If both gateway and interface are specified, they should not 629 * contradict. 630 * d) If we use tunnel routes, gateway could be not on-link. 631 * 632 * Attempt to reconcile all of these (alas, self-contradictory) conditions 633 * results in pretty ugly and hairy code with obscure logic. 634 * 635 * I chose to generalized it instead, so that the size 636 * of code does not increase practically, but it becomes 637 * much more general. 638 * Every prefix is assigned a "scope" value: "host" is local address, 639 * "link" is direct route, 640 * [ ... "site" ... "interior" ... ] 641 * and "universe" is true gateway route with global meaning. 642 * 643 * Every prefix refers to a set of "nexthop"s (gw, oif), 644 * where gw must have narrower scope. This recursion stops 645 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 646 * which means that gw is forced to be on link. 647 * 648 * Code is still hairy, but now it is apparently logically 649 * consistent and very flexible. F.e. as by-product it allows 650 * to co-exists in peace independent exterior and interior 651 * routing processes. 652 * 653 * Normally it looks as following. 654 * 655 * {universe prefix} -> (gw, oif) [scope link] 656 * | 657 * |-> {link prefix} -> (gw, oif) [scope local] 658 * | 659 * |-> {local prefix} (terminal node) 660 */ 661 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 662 struct fib_nh *nh) 663 { 664 int err; 665 struct net *net; 666 struct net_device *dev; 667 668 net = cfg->fc_nlinfo.nl_net; 669 if (nh->nh_gw) { 670 struct fib_result res; 671 672 if (nh->nh_flags & RTNH_F_ONLINK) { 673 674 if (cfg->fc_scope >= RT_SCOPE_LINK) 675 return -EINVAL; 676 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST) 677 return -EINVAL; 678 dev = __dev_get_by_index(net, nh->nh_oif); 679 if (!dev) 680 return -ENODEV; 681 if (!(dev->flags & IFF_UP)) 682 return -ENETDOWN; 683 if (!netif_carrier_ok(dev)) 684 nh->nh_flags |= RTNH_F_LINKDOWN; 685 nh->nh_dev = dev; 686 dev_hold(dev); 687 nh->nh_scope = RT_SCOPE_LINK; 688 return 0; 689 } 690 rcu_read_lock(); 691 { 692 struct flowi4 fl4 = { 693 .daddr = nh->nh_gw, 694 .flowi4_scope = cfg->fc_scope + 1, 695 .flowi4_oif = nh->nh_oif, 696 .flowi4_iif = LOOPBACK_IFINDEX, 697 }; 698 699 /* It is not necessary, but requires a bit of thinking */ 700 if (fl4.flowi4_scope < RT_SCOPE_LINK) 701 fl4.flowi4_scope = RT_SCOPE_LINK; 702 err = fib_lookup(net, &fl4, &res, 703 FIB_LOOKUP_IGNORE_LINKSTATE); 704 if (err) { 705 rcu_read_unlock(); 706 return err; 707 } 708 } 709 err = -EINVAL; 710 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 711 goto out; 712 nh->nh_scope = res.scope; 713 nh->nh_oif = FIB_RES_OIF(res); 714 nh->nh_dev = dev = FIB_RES_DEV(res); 715 if (!dev) 716 goto out; 717 dev_hold(dev); 718 if (!netif_carrier_ok(dev)) 719 nh->nh_flags |= RTNH_F_LINKDOWN; 720 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 721 } else { 722 struct in_device *in_dev; 723 724 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 725 return -EINVAL; 726 727 rcu_read_lock(); 728 err = -ENODEV; 729 in_dev = inetdev_by_index(net, nh->nh_oif); 730 if (!in_dev) 731 goto out; 732 err = -ENETDOWN; 733 if (!(in_dev->dev->flags & IFF_UP)) 734 goto out; 735 nh->nh_dev = in_dev->dev; 736 dev_hold(nh->nh_dev); 737 nh->nh_scope = RT_SCOPE_HOST; 738 if (!netif_carrier_ok(nh->nh_dev)) 739 nh->nh_flags |= RTNH_F_LINKDOWN; 740 err = 0; 741 } 742 out: 743 rcu_read_unlock(); 744 return err; 745 } 746 747 static inline unsigned int fib_laddr_hashfn(__be32 val) 748 { 749 unsigned int mask = (fib_info_hash_size - 1); 750 751 return ((__force u32)val ^ 752 ((__force u32)val >> 7) ^ 753 ((__force u32)val >> 14)) & mask; 754 } 755 756 static struct hlist_head *fib_info_hash_alloc(int bytes) 757 { 758 if (bytes <= PAGE_SIZE) 759 return kzalloc(bytes, GFP_KERNEL); 760 else 761 return (struct hlist_head *) 762 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 763 get_order(bytes)); 764 } 765 766 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 767 { 768 if (!hash) 769 return; 770 771 if (bytes <= PAGE_SIZE) 772 kfree(hash); 773 else 774 free_pages((unsigned long) hash, get_order(bytes)); 775 } 776 777 static void fib_info_hash_move(struct hlist_head *new_info_hash, 778 struct hlist_head *new_laddrhash, 779 unsigned int new_size) 780 { 781 struct hlist_head *old_info_hash, *old_laddrhash; 782 unsigned int old_size = fib_info_hash_size; 783 unsigned int i, bytes; 784 785 spin_lock_bh(&fib_info_lock); 786 old_info_hash = fib_info_hash; 787 old_laddrhash = fib_info_laddrhash; 788 fib_info_hash_size = new_size; 789 790 for (i = 0; i < old_size; i++) { 791 struct hlist_head *head = &fib_info_hash[i]; 792 struct hlist_node *n; 793 struct fib_info *fi; 794 795 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 796 struct hlist_head *dest; 797 unsigned int new_hash; 798 799 new_hash = fib_info_hashfn(fi); 800 dest = &new_info_hash[new_hash]; 801 hlist_add_head(&fi->fib_hash, dest); 802 } 803 } 804 fib_info_hash = new_info_hash; 805 806 for (i = 0; i < old_size; i++) { 807 struct hlist_head *lhead = &fib_info_laddrhash[i]; 808 struct hlist_node *n; 809 struct fib_info *fi; 810 811 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 812 struct hlist_head *ldest; 813 unsigned int new_hash; 814 815 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 816 ldest = &new_laddrhash[new_hash]; 817 hlist_add_head(&fi->fib_lhash, ldest); 818 } 819 } 820 fib_info_laddrhash = new_laddrhash; 821 822 spin_unlock_bh(&fib_info_lock); 823 824 bytes = old_size * sizeof(struct hlist_head *); 825 fib_info_hash_free(old_info_hash, bytes); 826 fib_info_hash_free(old_laddrhash, bytes); 827 } 828 829 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 830 { 831 nh->nh_saddr = inet_select_addr(nh->nh_dev, 832 nh->nh_gw, 833 nh->nh_parent->fib_scope); 834 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 835 836 return nh->nh_saddr; 837 } 838 839 struct fib_info *fib_create_info(struct fib_config *cfg) 840 { 841 int err; 842 struct fib_info *fi = NULL; 843 struct fib_info *ofi; 844 int nhs = 1; 845 struct net *net = cfg->fc_nlinfo.nl_net; 846 847 if (cfg->fc_type > RTN_MAX) 848 goto err_inval; 849 850 /* Fast check to catch the most weird cases */ 851 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 852 goto err_inval; 853 854 #ifdef CONFIG_IP_ROUTE_MULTIPATH 855 if (cfg->fc_mp) { 856 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 857 if (nhs == 0) 858 goto err_inval; 859 } 860 #endif 861 862 err = -ENOBUFS; 863 if (fib_info_cnt >= fib_info_hash_size) { 864 unsigned int new_size = fib_info_hash_size << 1; 865 struct hlist_head *new_info_hash; 866 struct hlist_head *new_laddrhash; 867 unsigned int bytes; 868 869 if (!new_size) 870 new_size = 16; 871 bytes = new_size * sizeof(struct hlist_head *); 872 new_info_hash = fib_info_hash_alloc(bytes); 873 new_laddrhash = fib_info_hash_alloc(bytes); 874 if (!new_info_hash || !new_laddrhash) { 875 fib_info_hash_free(new_info_hash, bytes); 876 fib_info_hash_free(new_laddrhash, bytes); 877 } else 878 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 879 880 if (!fib_info_hash_size) 881 goto failure; 882 } 883 884 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 885 if (!fi) 886 goto failure; 887 fib_info_cnt++; 888 if (cfg->fc_mx) { 889 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 890 if (!fi->fib_metrics) 891 goto failure; 892 } else 893 fi->fib_metrics = (u32 *) dst_default_metrics; 894 895 fi->fib_net = net; 896 fi->fib_protocol = cfg->fc_protocol; 897 fi->fib_scope = cfg->fc_scope; 898 fi->fib_flags = cfg->fc_flags; 899 fi->fib_priority = cfg->fc_priority; 900 fi->fib_prefsrc = cfg->fc_prefsrc; 901 fi->fib_type = cfg->fc_type; 902 903 fi->fib_nhs = nhs; 904 change_nexthops(fi) { 905 nexthop_nh->nh_parent = fi; 906 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 907 if (!nexthop_nh->nh_pcpu_rth_output) 908 goto failure; 909 } endfor_nexthops(fi) 910 911 if (cfg->fc_mx) { 912 struct nlattr *nla; 913 int remaining; 914 915 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 916 int type = nla_type(nla); 917 918 if (type) { 919 u32 val; 920 921 if (type > RTAX_MAX) 922 goto err_inval; 923 if (type == RTAX_CC_ALGO) { 924 char tmp[TCP_CA_NAME_MAX]; 925 926 nla_strlcpy(tmp, nla, sizeof(tmp)); 927 val = tcp_ca_get_key_by_name(tmp); 928 if (val == TCP_CA_UNSPEC) 929 goto err_inval; 930 } else { 931 val = nla_get_u32(nla); 932 } 933 if (type == RTAX_ADVMSS && val > 65535 - 40) 934 val = 65535 - 40; 935 if (type == RTAX_MTU && val > 65535 - 15) 936 val = 65535 - 15; 937 fi->fib_metrics[type - 1] = val; 938 } 939 } 940 } 941 942 if (cfg->fc_mp) { 943 #ifdef CONFIG_IP_ROUTE_MULTIPATH 944 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 945 if (err != 0) 946 goto failure; 947 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 948 goto err_inval; 949 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 950 goto err_inval; 951 #ifdef CONFIG_IP_ROUTE_CLASSID 952 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 953 goto err_inval; 954 #endif 955 #else 956 goto err_inval; 957 #endif 958 } else { 959 struct fib_nh *nh = fi->fib_nh; 960 961 if (cfg->fc_encap) { 962 struct lwtunnel_state *lwtstate; 963 struct net_device *dev = NULL; 964 965 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) 966 goto err_inval; 967 if (cfg->fc_oif) 968 dev = __dev_get_by_index(net, cfg->fc_oif); 969 err = lwtunnel_build_state(dev, cfg->fc_encap_type, 970 cfg->fc_encap, &lwtstate); 971 if (err) 972 goto failure; 973 974 nh->nh_lwtstate = lwtstate_get(lwtstate); 975 } 976 nh->nh_oif = cfg->fc_oif; 977 nh->nh_gw = cfg->fc_gw; 978 nh->nh_flags = cfg->fc_flags; 979 #ifdef CONFIG_IP_ROUTE_CLASSID 980 nh->nh_tclassid = cfg->fc_flow; 981 if (nh->nh_tclassid) 982 fi->fib_net->ipv4.fib_num_tclassid_users++; 983 #endif 984 #ifdef CONFIG_IP_ROUTE_MULTIPATH 985 nh->nh_weight = 1; 986 #endif 987 } 988 989 if (fib_props[cfg->fc_type].error) { 990 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 991 goto err_inval; 992 goto link_it; 993 } else { 994 switch (cfg->fc_type) { 995 case RTN_UNICAST: 996 case RTN_LOCAL: 997 case RTN_BROADCAST: 998 case RTN_ANYCAST: 999 case RTN_MULTICAST: 1000 break; 1001 default: 1002 goto err_inval; 1003 } 1004 } 1005 1006 if (cfg->fc_scope > RT_SCOPE_HOST) 1007 goto err_inval; 1008 1009 if (cfg->fc_scope == RT_SCOPE_HOST) { 1010 struct fib_nh *nh = fi->fib_nh; 1011 1012 /* Local address is added. */ 1013 if (nhs != 1 || nh->nh_gw) 1014 goto err_inval; 1015 nh->nh_scope = RT_SCOPE_NOWHERE; 1016 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1017 err = -ENODEV; 1018 if (!nh->nh_dev) 1019 goto failure; 1020 } else { 1021 int linkdown = 0; 1022 1023 change_nexthops(fi) { 1024 err = fib_check_nh(cfg, fi, nexthop_nh); 1025 if (err != 0) 1026 goto failure; 1027 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1028 linkdown++; 1029 } endfor_nexthops(fi) 1030 if (linkdown == fi->fib_nhs) 1031 fi->fib_flags |= RTNH_F_LINKDOWN; 1032 } 1033 1034 if (fi->fib_prefsrc) { 1035 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1036 fi->fib_prefsrc != cfg->fc_dst) 1037 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL) 1038 goto err_inval; 1039 } 1040 1041 change_nexthops(fi) { 1042 fib_info_update_nh_saddr(net, nexthop_nh); 1043 } endfor_nexthops(fi) 1044 1045 link_it: 1046 ofi = fib_find_info(fi); 1047 if (ofi) { 1048 fi->fib_dead = 1; 1049 free_fib_info(fi); 1050 ofi->fib_treeref++; 1051 return ofi; 1052 } 1053 1054 fi->fib_treeref++; 1055 atomic_inc(&fi->fib_clntref); 1056 spin_lock_bh(&fib_info_lock); 1057 hlist_add_head(&fi->fib_hash, 1058 &fib_info_hash[fib_info_hashfn(fi)]); 1059 if (fi->fib_prefsrc) { 1060 struct hlist_head *head; 1061 1062 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1063 hlist_add_head(&fi->fib_lhash, head); 1064 } 1065 change_nexthops(fi) { 1066 struct hlist_head *head; 1067 unsigned int hash; 1068 1069 if (!nexthop_nh->nh_dev) 1070 continue; 1071 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1072 head = &fib_info_devhash[hash]; 1073 hlist_add_head(&nexthop_nh->nh_hash, head); 1074 } endfor_nexthops(fi) 1075 spin_unlock_bh(&fib_info_lock); 1076 return fi; 1077 1078 err_inval: 1079 err = -EINVAL; 1080 1081 failure: 1082 if (fi) { 1083 fi->fib_dead = 1; 1084 free_fib_info(fi); 1085 } 1086 1087 return ERR_PTR(err); 1088 } 1089 1090 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1091 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1092 struct fib_info *fi, unsigned int flags) 1093 { 1094 struct nlmsghdr *nlh; 1095 struct rtmsg *rtm; 1096 1097 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1098 if (!nlh) 1099 return -EMSGSIZE; 1100 1101 rtm = nlmsg_data(nlh); 1102 rtm->rtm_family = AF_INET; 1103 rtm->rtm_dst_len = dst_len; 1104 rtm->rtm_src_len = 0; 1105 rtm->rtm_tos = tos; 1106 if (tb_id < 256) 1107 rtm->rtm_table = tb_id; 1108 else 1109 rtm->rtm_table = RT_TABLE_COMPAT; 1110 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1111 goto nla_put_failure; 1112 rtm->rtm_type = type; 1113 rtm->rtm_flags = fi->fib_flags; 1114 rtm->rtm_scope = fi->fib_scope; 1115 rtm->rtm_protocol = fi->fib_protocol; 1116 1117 if (rtm->rtm_dst_len && 1118 nla_put_in_addr(skb, RTA_DST, dst)) 1119 goto nla_put_failure; 1120 if (fi->fib_priority && 1121 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1122 goto nla_put_failure; 1123 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1124 goto nla_put_failure; 1125 1126 if (fi->fib_prefsrc && 1127 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1128 goto nla_put_failure; 1129 if (fi->fib_nhs == 1) { 1130 struct in_device *in_dev; 1131 1132 if (fi->fib_nh->nh_gw && 1133 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1134 goto nla_put_failure; 1135 if (fi->fib_nh->nh_oif && 1136 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1137 goto nla_put_failure; 1138 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1139 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1140 if (in_dev && 1141 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1142 rtm->rtm_flags |= RTNH_F_DEAD; 1143 } 1144 #ifdef CONFIG_IP_ROUTE_CLASSID 1145 if (fi->fib_nh[0].nh_tclassid && 1146 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1147 goto nla_put_failure; 1148 #endif 1149 if (fi->fib_nh->nh_lwtstate) 1150 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate); 1151 } 1152 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1153 if (fi->fib_nhs > 1) { 1154 struct rtnexthop *rtnh; 1155 struct nlattr *mp; 1156 1157 mp = nla_nest_start(skb, RTA_MULTIPATH); 1158 if (!mp) 1159 goto nla_put_failure; 1160 1161 for_nexthops(fi) { 1162 struct in_device *in_dev; 1163 1164 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1165 if (!rtnh) 1166 goto nla_put_failure; 1167 1168 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1169 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1170 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1171 if (in_dev && 1172 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1173 rtnh->rtnh_flags |= RTNH_F_DEAD; 1174 } 1175 rtnh->rtnh_hops = nh->nh_weight - 1; 1176 rtnh->rtnh_ifindex = nh->nh_oif; 1177 1178 if (nh->nh_gw && 1179 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1180 goto nla_put_failure; 1181 #ifdef CONFIG_IP_ROUTE_CLASSID 1182 if (nh->nh_tclassid && 1183 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1184 goto nla_put_failure; 1185 #endif 1186 if (nh->nh_lwtstate) 1187 lwtunnel_fill_encap(skb, nh->nh_lwtstate); 1188 /* length of rtnetlink header + attributes */ 1189 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1190 } endfor_nexthops(fi); 1191 1192 nla_nest_end(skb, mp); 1193 } 1194 #endif 1195 nlmsg_end(skb, nlh); 1196 return 0; 1197 1198 nla_put_failure: 1199 nlmsg_cancel(skb, nlh); 1200 return -EMSGSIZE; 1201 } 1202 1203 /* 1204 * Update FIB if: 1205 * - local address disappeared -> we must delete all the entries 1206 * referring to it. 1207 * - device went down -> we must shutdown all nexthops going via it. 1208 */ 1209 int fib_sync_down_addr(struct net *net, __be32 local) 1210 { 1211 int ret = 0; 1212 unsigned int hash = fib_laddr_hashfn(local); 1213 struct hlist_head *head = &fib_info_laddrhash[hash]; 1214 struct fib_info *fi; 1215 1216 if (!fib_info_laddrhash || local == 0) 1217 return 0; 1218 1219 hlist_for_each_entry(fi, head, fib_lhash) { 1220 if (!net_eq(fi->fib_net, net)) 1221 continue; 1222 if (fi->fib_prefsrc == local) { 1223 fi->fib_flags |= RTNH_F_DEAD; 1224 ret++; 1225 } 1226 } 1227 return ret; 1228 } 1229 1230 int fib_sync_down_dev(struct net_device *dev, unsigned long event) 1231 { 1232 int ret = 0; 1233 int scope = RT_SCOPE_NOWHERE; 1234 struct fib_info *prev_fi = NULL; 1235 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1236 struct hlist_head *head = &fib_info_devhash[hash]; 1237 struct fib_nh *nh; 1238 1239 if (event == NETDEV_UNREGISTER || 1240 event == NETDEV_DOWN) 1241 scope = -1; 1242 1243 hlist_for_each_entry(nh, head, nh_hash) { 1244 struct fib_info *fi = nh->nh_parent; 1245 int dead; 1246 1247 BUG_ON(!fi->fib_nhs); 1248 if (nh->nh_dev != dev || fi == prev_fi) 1249 continue; 1250 prev_fi = fi; 1251 dead = 0; 1252 change_nexthops(fi) { 1253 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1254 dead++; 1255 else if (nexthop_nh->nh_dev == dev && 1256 nexthop_nh->nh_scope != scope) { 1257 switch (event) { 1258 case NETDEV_DOWN: 1259 case NETDEV_UNREGISTER: 1260 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1261 /* fall through */ 1262 case NETDEV_CHANGE: 1263 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1264 break; 1265 } 1266 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1267 spin_lock_bh(&fib_multipath_lock); 1268 fi->fib_power -= nexthop_nh->nh_power; 1269 nexthop_nh->nh_power = 0; 1270 spin_unlock_bh(&fib_multipath_lock); 1271 #endif 1272 dead++; 1273 } 1274 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1275 if (event == NETDEV_UNREGISTER && 1276 nexthop_nh->nh_dev == dev) { 1277 dead = fi->fib_nhs; 1278 break; 1279 } 1280 #endif 1281 } endfor_nexthops(fi) 1282 if (dead == fi->fib_nhs) { 1283 switch (event) { 1284 case NETDEV_DOWN: 1285 case NETDEV_UNREGISTER: 1286 fi->fib_flags |= RTNH_F_DEAD; 1287 /* fall through */ 1288 case NETDEV_CHANGE: 1289 fi->fib_flags |= RTNH_F_LINKDOWN; 1290 break; 1291 } 1292 ret++; 1293 } 1294 } 1295 1296 return ret; 1297 } 1298 1299 /* Must be invoked inside of an RCU protected region. */ 1300 void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1301 { 1302 struct fib_info *fi = NULL, *last_resort = NULL; 1303 struct hlist_head *fa_head = res->fa_head; 1304 struct fib_table *tb = res->table; 1305 u8 slen = 32 - res->prefixlen; 1306 int order = -1, last_idx = -1; 1307 struct fib_alias *fa, *fa1 = NULL; 1308 u32 last_prio = res->fi->fib_priority; 1309 u8 last_tos = 0; 1310 1311 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1312 struct fib_info *next_fi = fa->fa_info; 1313 1314 if (fa->fa_slen != slen) 1315 continue; 1316 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1317 continue; 1318 if (fa->tb_id != tb->tb_id) 1319 continue; 1320 if (next_fi->fib_priority > last_prio && 1321 fa->fa_tos == last_tos) { 1322 if (last_tos) 1323 continue; 1324 break; 1325 } 1326 if (next_fi->fib_flags & RTNH_F_DEAD) 1327 continue; 1328 last_tos = fa->fa_tos; 1329 last_prio = next_fi->fib_priority; 1330 1331 if (next_fi->fib_scope != res->scope || 1332 fa->fa_type != RTN_UNICAST) 1333 continue; 1334 if (!next_fi->fib_nh[0].nh_gw || 1335 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1336 continue; 1337 1338 fib_alias_accessed(fa); 1339 1340 if (!fi) { 1341 if (next_fi != res->fi) 1342 break; 1343 fa1 = fa; 1344 } else if (!fib_detect_death(fi, order, &last_resort, 1345 &last_idx, fa1->fa_default)) { 1346 fib_result_assign(res, fi); 1347 fa1->fa_default = order; 1348 goto out; 1349 } 1350 fi = next_fi; 1351 order++; 1352 } 1353 1354 if (order <= 0 || !fi) { 1355 if (fa1) 1356 fa1->fa_default = -1; 1357 goto out; 1358 } 1359 1360 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1361 fa1->fa_default)) { 1362 fib_result_assign(res, fi); 1363 fa1->fa_default = order; 1364 goto out; 1365 } 1366 1367 if (last_idx >= 0) 1368 fib_result_assign(res, last_resort); 1369 fa1->fa_default = last_idx; 1370 out: 1371 return; 1372 } 1373 1374 /* 1375 * Dead device goes up. We wake up dead nexthops. 1376 * It takes sense only on multipath routes. 1377 */ 1378 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1379 { 1380 struct fib_info *prev_fi; 1381 unsigned int hash; 1382 struct hlist_head *head; 1383 struct fib_nh *nh; 1384 int ret; 1385 1386 if (!(dev->flags & IFF_UP)) 1387 return 0; 1388 1389 prev_fi = NULL; 1390 hash = fib_devindex_hashfn(dev->ifindex); 1391 head = &fib_info_devhash[hash]; 1392 ret = 0; 1393 1394 hlist_for_each_entry(nh, head, nh_hash) { 1395 struct fib_info *fi = nh->nh_parent; 1396 int alive; 1397 1398 BUG_ON(!fi->fib_nhs); 1399 if (nh->nh_dev != dev || fi == prev_fi) 1400 continue; 1401 1402 prev_fi = fi; 1403 alive = 0; 1404 change_nexthops(fi) { 1405 if (!(nexthop_nh->nh_flags & nh_flags)) { 1406 alive++; 1407 continue; 1408 } 1409 if (!nexthop_nh->nh_dev || 1410 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1411 continue; 1412 if (nexthop_nh->nh_dev != dev || 1413 !__in_dev_get_rtnl(dev)) 1414 continue; 1415 alive++; 1416 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1417 spin_lock_bh(&fib_multipath_lock); 1418 nexthop_nh->nh_power = 0; 1419 nexthop_nh->nh_flags &= ~nh_flags; 1420 spin_unlock_bh(&fib_multipath_lock); 1421 #else 1422 nexthop_nh->nh_flags &= ~nh_flags; 1423 #endif 1424 } endfor_nexthops(fi) 1425 1426 if (alive > 0) { 1427 fi->fib_flags &= ~nh_flags; 1428 ret++; 1429 } 1430 } 1431 1432 return ret; 1433 } 1434 1435 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1436 1437 /* 1438 * The algorithm is suboptimal, but it provides really 1439 * fair weighted route distribution. 1440 */ 1441 void fib_select_multipath(struct fib_result *res) 1442 { 1443 struct fib_info *fi = res->fi; 1444 struct in_device *in_dev; 1445 int w; 1446 1447 spin_lock_bh(&fib_multipath_lock); 1448 if (fi->fib_power <= 0) { 1449 int power = 0; 1450 change_nexthops(fi) { 1451 in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev); 1452 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1453 continue; 1454 if (in_dev && 1455 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1456 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1457 continue; 1458 power += nexthop_nh->nh_weight; 1459 nexthop_nh->nh_power = nexthop_nh->nh_weight; 1460 } endfor_nexthops(fi); 1461 fi->fib_power = power; 1462 if (power <= 0) { 1463 spin_unlock_bh(&fib_multipath_lock); 1464 /* Race condition: route has just become dead. */ 1465 res->nh_sel = 0; 1466 return; 1467 } 1468 } 1469 1470 1471 /* w should be random number [0..fi->fib_power-1], 1472 * it is pretty bad approximation. 1473 */ 1474 1475 w = jiffies % fi->fib_power; 1476 1477 change_nexthops(fi) { 1478 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) && 1479 nexthop_nh->nh_power) { 1480 w -= nexthop_nh->nh_power; 1481 if (w <= 0) { 1482 nexthop_nh->nh_power--; 1483 fi->fib_power--; 1484 res->nh_sel = nhsel; 1485 spin_unlock_bh(&fib_multipath_lock); 1486 return; 1487 } 1488 } 1489 } endfor_nexthops(fi); 1490 1491 /* Race condition: route has just become dead. */ 1492 res->nh_sel = 0; 1493 spin_unlock_bh(&fib_multipath_lock); 1494 } 1495 #endif 1496