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, 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 #endif 536 537 static int fib_encap_match(struct net *net, u16 encap_type, 538 struct nlattr *encap, 539 int oif, const struct fib_nh *nh, 540 const struct fib_config *cfg) 541 { 542 struct lwtunnel_state *lwtstate; 543 struct net_device *dev = NULL; 544 int ret, result = 0; 545 546 if (encap_type == LWTUNNEL_ENCAP_NONE) 547 return 0; 548 549 if (oif) 550 dev = __dev_get_by_index(net, oif); 551 ret = lwtunnel_build_state(dev, encap_type, encap, 552 AF_INET, cfg, &lwtstate); 553 if (!ret) { 554 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 555 lwtstate_free(lwtstate); 556 } 557 558 return result; 559 } 560 561 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 562 { 563 struct net *net = cfg->fc_nlinfo.nl_net; 564 #ifdef CONFIG_IP_ROUTE_MULTIPATH 565 struct rtnexthop *rtnh; 566 int remaining; 567 #endif 568 569 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 570 return 1; 571 572 if (cfg->fc_oif || cfg->fc_gw) { 573 if (cfg->fc_encap) { 574 if (fib_encap_match(net, cfg->fc_encap_type, 575 cfg->fc_encap, cfg->fc_oif, 576 fi->fib_nh, cfg)) 577 return 1; 578 } 579 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 580 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 581 return 0; 582 return 1; 583 } 584 585 #ifdef CONFIG_IP_ROUTE_MULTIPATH 586 if (!cfg->fc_mp) 587 return 0; 588 589 rtnh = cfg->fc_mp; 590 remaining = cfg->fc_mp_len; 591 592 for_nexthops(fi) { 593 int attrlen; 594 595 if (!rtnh_ok(rtnh, remaining)) 596 return -EINVAL; 597 598 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 599 return 1; 600 601 attrlen = rtnh_attrlen(rtnh); 602 if (attrlen > 0) { 603 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 604 605 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 606 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 607 return 1; 608 #ifdef CONFIG_IP_ROUTE_CLASSID 609 nla = nla_find(attrs, attrlen, RTA_FLOW); 610 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 611 return 1; 612 #endif 613 } 614 615 rtnh = rtnh_next(rtnh, &remaining); 616 } endfor_nexthops(fi); 617 #endif 618 return 0; 619 } 620 621 622 /* 623 * Picture 624 * ------- 625 * 626 * Semantics of nexthop is very messy by historical reasons. 627 * We have to take into account, that: 628 * a) gateway can be actually local interface address, 629 * so that gatewayed route is direct. 630 * b) gateway must be on-link address, possibly 631 * described not by an ifaddr, but also by a direct route. 632 * c) If both gateway and interface are specified, they should not 633 * contradict. 634 * d) If we use tunnel routes, gateway could be not on-link. 635 * 636 * Attempt to reconcile all of these (alas, self-contradictory) conditions 637 * results in pretty ugly and hairy code with obscure logic. 638 * 639 * I chose to generalized it instead, so that the size 640 * of code does not increase practically, but it becomes 641 * much more general. 642 * Every prefix is assigned a "scope" value: "host" is local address, 643 * "link" is direct route, 644 * [ ... "site" ... "interior" ... ] 645 * and "universe" is true gateway route with global meaning. 646 * 647 * Every prefix refers to a set of "nexthop"s (gw, oif), 648 * where gw must have narrower scope. This recursion stops 649 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 650 * which means that gw is forced to be on link. 651 * 652 * Code is still hairy, but now it is apparently logically 653 * consistent and very flexible. F.e. as by-product it allows 654 * to co-exists in peace independent exterior and interior 655 * routing processes. 656 * 657 * Normally it looks as following. 658 * 659 * {universe prefix} -> (gw, oif) [scope link] 660 * | 661 * |-> {link prefix} -> (gw, oif) [scope local] 662 * | 663 * |-> {local prefix} (terminal node) 664 */ 665 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 666 struct fib_nh *nh) 667 { 668 int err = 0; 669 struct net *net; 670 struct net_device *dev; 671 672 net = cfg->fc_nlinfo.nl_net; 673 if (nh->nh_gw) { 674 struct fib_result res; 675 676 if (nh->nh_flags & RTNH_F_ONLINK) { 677 unsigned int addr_type; 678 679 if (cfg->fc_scope >= RT_SCOPE_LINK) 680 return -EINVAL; 681 dev = __dev_get_by_index(net, nh->nh_oif); 682 if (!dev) 683 return -ENODEV; 684 if (!(dev->flags & IFF_UP)) 685 return -ENETDOWN; 686 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 687 if (addr_type != RTN_UNICAST) 688 return -EINVAL; 689 if (!netif_carrier_ok(dev)) 690 nh->nh_flags |= RTNH_F_LINKDOWN; 691 nh->nh_dev = dev; 692 dev_hold(dev); 693 nh->nh_scope = RT_SCOPE_LINK; 694 return 0; 695 } 696 rcu_read_lock(); 697 { 698 struct fib_table *tbl = NULL; 699 struct flowi4 fl4 = { 700 .daddr = nh->nh_gw, 701 .flowi4_scope = cfg->fc_scope + 1, 702 .flowi4_oif = nh->nh_oif, 703 .flowi4_iif = LOOPBACK_IFINDEX, 704 }; 705 706 /* It is not necessary, but requires a bit of thinking */ 707 if (fl4.flowi4_scope < RT_SCOPE_LINK) 708 fl4.flowi4_scope = RT_SCOPE_LINK; 709 710 if (cfg->fc_table) 711 tbl = fib_get_table(net, cfg->fc_table); 712 713 if (tbl) 714 err = fib_table_lookup(tbl, &fl4, &res, 715 FIB_LOOKUP_IGNORE_LINKSTATE | 716 FIB_LOOKUP_NOREF); 717 718 /* on error or if no table given do full lookup. This 719 * is needed for example when nexthops are in the local 720 * table rather than the given table 721 */ 722 if (!tbl || err) { 723 err = fib_lookup(net, &fl4, &res, 724 FIB_LOOKUP_IGNORE_LINKSTATE); 725 } 726 727 if (err) { 728 rcu_read_unlock(); 729 return err; 730 } 731 } 732 err = -EINVAL; 733 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 734 goto out; 735 nh->nh_scope = res.scope; 736 nh->nh_oif = FIB_RES_OIF(res); 737 nh->nh_dev = dev = FIB_RES_DEV(res); 738 if (!dev) 739 goto out; 740 dev_hold(dev); 741 if (!netif_carrier_ok(dev)) 742 nh->nh_flags |= RTNH_F_LINKDOWN; 743 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 744 } else { 745 struct in_device *in_dev; 746 747 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 748 return -EINVAL; 749 750 rcu_read_lock(); 751 err = -ENODEV; 752 in_dev = inetdev_by_index(net, nh->nh_oif); 753 if (!in_dev) 754 goto out; 755 err = -ENETDOWN; 756 if (!(in_dev->dev->flags & IFF_UP)) 757 goto out; 758 nh->nh_dev = in_dev->dev; 759 dev_hold(nh->nh_dev); 760 nh->nh_scope = RT_SCOPE_HOST; 761 if (!netif_carrier_ok(nh->nh_dev)) 762 nh->nh_flags |= RTNH_F_LINKDOWN; 763 err = 0; 764 } 765 out: 766 rcu_read_unlock(); 767 return err; 768 } 769 770 static inline unsigned int fib_laddr_hashfn(__be32 val) 771 { 772 unsigned int mask = (fib_info_hash_size - 1); 773 774 return ((__force u32)val ^ 775 ((__force u32)val >> 7) ^ 776 ((__force u32)val >> 14)) & mask; 777 } 778 779 static struct hlist_head *fib_info_hash_alloc(int bytes) 780 { 781 if (bytes <= PAGE_SIZE) 782 return kzalloc(bytes, GFP_KERNEL); 783 else 784 return (struct hlist_head *) 785 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 786 get_order(bytes)); 787 } 788 789 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 790 { 791 if (!hash) 792 return; 793 794 if (bytes <= PAGE_SIZE) 795 kfree(hash); 796 else 797 free_pages((unsigned long) hash, get_order(bytes)); 798 } 799 800 static void fib_info_hash_move(struct hlist_head *new_info_hash, 801 struct hlist_head *new_laddrhash, 802 unsigned int new_size) 803 { 804 struct hlist_head *old_info_hash, *old_laddrhash; 805 unsigned int old_size = fib_info_hash_size; 806 unsigned int i, bytes; 807 808 spin_lock_bh(&fib_info_lock); 809 old_info_hash = fib_info_hash; 810 old_laddrhash = fib_info_laddrhash; 811 fib_info_hash_size = new_size; 812 813 for (i = 0; i < old_size; i++) { 814 struct hlist_head *head = &fib_info_hash[i]; 815 struct hlist_node *n; 816 struct fib_info *fi; 817 818 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 819 struct hlist_head *dest; 820 unsigned int new_hash; 821 822 new_hash = fib_info_hashfn(fi); 823 dest = &new_info_hash[new_hash]; 824 hlist_add_head(&fi->fib_hash, dest); 825 } 826 } 827 fib_info_hash = new_info_hash; 828 829 for (i = 0; i < old_size; i++) { 830 struct hlist_head *lhead = &fib_info_laddrhash[i]; 831 struct hlist_node *n; 832 struct fib_info *fi; 833 834 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 835 struct hlist_head *ldest; 836 unsigned int new_hash; 837 838 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 839 ldest = &new_laddrhash[new_hash]; 840 hlist_add_head(&fi->fib_lhash, ldest); 841 } 842 } 843 fib_info_laddrhash = new_laddrhash; 844 845 spin_unlock_bh(&fib_info_lock); 846 847 bytes = old_size * sizeof(struct hlist_head *); 848 fib_info_hash_free(old_info_hash, bytes); 849 fib_info_hash_free(old_laddrhash, bytes); 850 } 851 852 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 853 { 854 nh->nh_saddr = inet_select_addr(nh->nh_dev, 855 nh->nh_gw, 856 nh->nh_parent->fib_scope); 857 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 858 859 return nh->nh_saddr; 860 } 861 862 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 863 { 864 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 865 fib_prefsrc != cfg->fc_dst) { 866 u32 tb_id = cfg->fc_table; 867 868 if (tb_id == RT_TABLE_MAIN) 869 tb_id = RT_TABLE_LOCAL; 870 871 if (inet_addr_type_table(cfg->fc_nlinfo.nl_net, 872 fib_prefsrc, tb_id) != RTN_LOCAL) { 873 return false; 874 } 875 } 876 return true; 877 } 878 879 static int 880 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 881 { 882 bool ecn_ca = false; 883 struct nlattr *nla; 884 int remaining; 885 886 if (!cfg->fc_mx) 887 return 0; 888 889 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 890 int type = nla_type(nla); 891 u32 val; 892 893 if (!type) 894 continue; 895 if (type > RTAX_MAX) 896 return -EINVAL; 897 898 if (type == RTAX_CC_ALGO) { 899 char tmp[TCP_CA_NAME_MAX]; 900 901 nla_strlcpy(tmp, nla, sizeof(tmp)); 902 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 903 if (val == TCP_CA_UNSPEC) 904 return -EINVAL; 905 } else { 906 val = nla_get_u32(nla); 907 } 908 if (type == RTAX_ADVMSS && val > 65535 - 40) 909 val = 65535 - 40; 910 if (type == RTAX_MTU && val > 65535 - 15) 911 val = 65535 - 15; 912 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 913 return -EINVAL; 914 fi->fib_metrics[type - 1] = val; 915 } 916 917 if (ecn_ca) 918 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 919 920 return 0; 921 } 922 923 struct fib_info *fib_create_info(struct fib_config *cfg) 924 { 925 int err; 926 struct fib_info *fi = NULL; 927 struct fib_info *ofi; 928 int nhs = 1; 929 struct net *net = cfg->fc_nlinfo.nl_net; 930 931 if (cfg->fc_type > RTN_MAX) 932 goto err_inval; 933 934 /* Fast check to catch the most weird cases */ 935 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 936 goto err_inval; 937 938 #ifdef CONFIG_IP_ROUTE_MULTIPATH 939 if (cfg->fc_mp) { 940 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 941 if (nhs == 0) 942 goto err_inval; 943 } 944 #endif 945 946 err = -ENOBUFS; 947 if (fib_info_cnt >= fib_info_hash_size) { 948 unsigned int new_size = fib_info_hash_size << 1; 949 struct hlist_head *new_info_hash; 950 struct hlist_head *new_laddrhash; 951 unsigned int bytes; 952 953 if (!new_size) 954 new_size = 16; 955 bytes = new_size * sizeof(struct hlist_head *); 956 new_info_hash = fib_info_hash_alloc(bytes); 957 new_laddrhash = fib_info_hash_alloc(bytes); 958 if (!new_info_hash || !new_laddrhash) { 959 fib_info_hash_free(new_info_hash, bytes); 960 fib_info_hash_free(new_laddrhash, bytes); 961 } else 962 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 963 964 if (!fib_info_hash_size) 965 goto failure; 966 } 967 968 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 969 if (!fi) 970 goto failure; 971 fib_info_cnt++; 972 if (cfg->fc_mx) { 973 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 974 if (!fi->fib_metrics) 975 goto failure; 976 } else 977 fi->fib_metrics = (u32 *) dst_default_metrics; 978 979 fi->fib_net = net; 980 fi->fib_protocol = cfg->fc_protocol; 981 fi->fib_scope = cfg->fc_scope; 982 fi->fib_flags = cfg->fc_flags; 983 fi->fib_priority = cfg->fc_priority; 984 fi->fib_prefsrc = cfg->fc_prefsrc; 985 fi->fib_type = cfg->fc_type; 986 987 fi->fib_nhs = nhs; 988 change_nexthops(fi) { 989 nexthop_nh->nh_parent = fi; 990 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 991 if (!nexthop_nh->nh_pcpu_rth_output) 992 goto failure; 993 } endfor_nexthops(fi) 994 995 err = fib_convert_metrics(fi, cfg); 996 if (err) 997 goto failure; 998 999 if (cfg->fc_mp) { 1000 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1001 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 1002 if (err != 0) 1003 goto failure; 1004 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 1005 goto err_inval; 1006 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 1007 goto err_inval; 1008 #ifdef CONFIG_IP_ROUTE_CLASSID 1009 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 1010 goto err_inval; 1011 #endif 1012 #else 1013 goto err_inval; 1014 #endif 1015 } else { 1016 struct fib_nh *nh = fi->fib_nh; 1017 1018 if (cfg->fc_encap) { 1019 struct lwtunnel_state *lwtstate; 1020 struct net_device *dev = NULL; 1021 1022 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) 1023 goto err_inval; 1024 if (cfg->fc_oif) 1025 dev = __dev_get_by_index(net, cfg->fc_oif); 1026 err = lwtunnel_build_state(dev, cfg->fc_encap_type, 1027 cfg->fc_encap, AF_INET, cfg, 1028 &lwtstate); 1029 if (err) 1030 goto failure; 1031 1032 nh->nh_lwtstate = lwtstate_get(lwtstate); 1033 } 1034 nh->nh_oif = cfg->fc_oif; 1035 nh->nh_gw = cfg->fc_gw; 1036 nh->nh_flags = cfg->fc_flags; 1037 #ifdef CONFIG_IP_ROUTE_CLASSID 1038 nh->nh_tclassid = cfg->fc_flow; 1039 if (nh->nh_tclassid) 1040 fi->fib_net->ipv4.fib_num_tclassid_users++; 1041 #endif 1042 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1043 nh->nh_weight = 1; 1044 #endif 1045 } 1046 1047 if (fib_props[cfg->fc_type].error) { 1048 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 1049 goto err_inval; 1050 goto link_it; 1051 } else { 1052 switch (cfg->fc_type) { 1053 case RTN_UNICAST: 1054 case RTN_LOCAL: 1055 case RTN_BROADCAST: 1056 case RTN_ANYCAST: 1057 case RTN_MULTICAST: 1058 break; 1059 default: 1060 goto err_inval; 1061 } 1062 } 1063 1064 if (cfg->fc_scope > RT_SCOPE_HOST) 1065 goto err_inval; 1066 1067 if (cfg->fc_scope == RT_SCOPE_HOST) { 1068 struct fib_nh *nh = fi->fib_nh; 1069 1070 /* Local address is added. */ 1071 if (nhs != 1 || nh->nh_gw) 1072 goto err_inval; 1073 nh->nh_scope = RT_SCOPE_NOWHERE; 1074 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1075 err = -ENODEV; 1076 if (!nh->nh_dev) 1077 goto failure; 1078 } else { 1079 int linkdown = 0; 1080 1081 change_nexthops(fi) { 1082 err = fib_check_nh(cfg, fi, nexthop_nh); 1083 if (err != 0) 1084 goto failure; 1085 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1086 linkdown++; 1087 } endfor_nexthops(fi) 1088 if (linkdown == fi->fib_nhs) 1089 fi->fib_flags |= RTNH_F_LINKDOWN; 1090 } 1091 1092 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) 1093 goto err_inval; 1094 1095 change_nexthops(fi) { 1096 fib_info_update_nh_saddr(net, nexthop_nh); 1097 } endfor_nexthops(fi) 1098 1099 link_it: 1100 ofi = fib_find_info(fi); 1101 if (ofi) { 1102 fi->fib_dead = 1; 1103 free_fib_info(fi); 1104 ofi->fib_treeref++; 1105 return ofi; 1106 } 1107 1108 fi->fib_treeref++; 1109 atomic_inc(&fi->fib_clntref); 1110 spin_lock_bh(&fib_info_lock); 1111 hlist_add_head(&fi->fib_hash, 1112 &fib_info_hash[fib_info_hashfn(fi)]); 1113 if (fi->fib_prefsrc) { 1114 struct hlist_head *head; 1115 1116 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1117 hlist_add_head(&fi->fib_lhash, head); 1118 } 1119 change_nexthops(fi) { 1120 struct hlist_head *head; 1121 unsigned int hash; 1122 1123 if (!nexthop_nh->nh_dev) 1124 continue; 1125 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1126 head = &fib_info_devhash[hash]; 1127 hlist_add_head(&nexthop_nh->nh_hash, head); 1128 } endfor_nexthops(fi) 1129 spin_unlock_bh(&fib_info_lock); 1130 return fi; 1131 1132 err_inval: 1133 err = -EINVAL; 1134 1135 failure: 1136 if (fi) { 1137 fi->fib_dead = 1; 1138 free_fib_info(fi); 1139 } 1140 1141 return ERR_PTR(err); 1142 } 1143 1144 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1145 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1146 struct fib_info *fi, unsigned int flags) 1147 { 1148 struct nlmsghdr *nlh; 1149 struct rtmsg *rtm; 1150 1151 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1152 if (!nlh) 1153 return -EMSGSIZE; 1154 1155 rtm = nlmsg_data(nlh); 1156 rtm->rtm_family = AF_INET; 1157 rtm->rtm_dst_len = dst_len; 1158 rtm->rtm_src_len = 0; 1159 rtm->rtm_tos = tos; 1160 if (tb_id < 256) 1161 rtm->rtm_table = tb_id; 1162 else 1163 rtm->rtm_table = RT_TABLE_COMPAT; 1164 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1165 goto nla_put_failure; 1166 rtm->rtm_type = type; 1167 rtm->rtm_flags = fi->fib_flags; 1168 rtm->rtm_scope = fi->fib_scope; 1169 rtm->rtm_protocol = fi->fib_protocol; 1170 1171 if (rtm->rtm_dst_len && 1172 nla_put_in_addr(skb, RTA_DST, dst)) 1173 goto nla_put_failure; 1174 if (fi->fib_priority && 1175 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1176 goto nla_put_failure; 1177 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1178 goto nla_put_failure; 1179 1180 if (fi->fib_prefsrc && 1181 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1182 goto nla_put_failure; 1183 if (fi->fib_nhs == 1) { 1184 struct in_device *in_dev; 1185 1186 if (fi->fib_nh->nh_gw && 1187 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1188 goto nla_put_failure; 1189 if (fi->fib_nh->nh_oif && 1190 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1191 goto nla_put_failure; 1192 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1193 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1194 if (in_dev && 1195 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1196 rtm->rtm_flags |= RTNH_F_DEAD; 1197 } 1198 #ifdef CONFIG_IP_ROUTE_CLASSID 1199 if (fi->fib_nh[0].nh_tclassid && 1200 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1201 goto nla_put_failure; 1202 #endif 1203 if (fi->fib_nh->nh_lwtstate) 1204 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate); 1205 } 1206 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1207 if (fi->fib_nhs > 1) { 1208 struct rtnexthop *rtnh; 1209 struct nlattr *mp; 1210 1211 mp = nla_nest_start(skb, RTA_MULTIPATH); 1212 if (!mp) 1213 goto nla_put_failure; 1214 1215 for_nexthops(fi) { 1216 struct in_device *in_dev; 1217 1218 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1219 if (!rtnh) 1220 goto nla_put_failure; 1221 1222 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1223 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1224 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1225 if (in_dev && 1226 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1227 rtnh->rtnh_flags |= RTNH_F_DEAD; 1228 } 1229 rtnh->rtnh_hops = nh->nh_weight - 1; 1230 rtnh->rtnh_ifindex = nh->nh_oif; 1231 1232 if (nh->nh_gw && 1233 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1234 goto nla_put_failure; 1235 #ifdef CONFIG_IP_ROUTE_CLASSID 1236 if (nh->nh_tclassid && 1237 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1238 goto nla_put_failure; 1239 #endif 1240 if (nh->nh_lwtstate) 1241 lwtunnel_fill_encap(skb, nh->nh_lwtstate); 1242 /* length of rtnetlink header + attributes */ 1243 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1244 } endfor_nexthops(fi); 1245 1246 nla_nest_end(skb, mp); 1247 } 1248 #endif 1249 nlmsg_end(skb, nlh); 1250 return 0; 1251 1252 nla_put_failure: 1253 nlmsg_cancel(skb, nlh); 1254 return -EMSGSIZE; 1255 } 1256 1257 /* 1258 * Update FIB if: 1259 * - local address disappeared -> we must delete all the entries 1260 * referring to it. 1261 * - device went down -> we must shutdown all nexthops going via it. 1262 */ 1263 int fib_sync_down_addr(struct net *net, __be32 local) 1264 { 1265 int ret = 0; 1266 unsigned int hash = fib_laddr_hashfn(local); 1267 struct hlist_head *head = &fib_info_laddrhash[hash]; 1268 struct fib_info *fi; 1269 1270 if (!fib_info_laddrhash || local == 0) 1271 return 0; 1272 1273 hlist_for_each_entry(fi, head, fib_lhash) { 1274 if (!net_eq(fi->fib_net, net)) 1275 continue; 1276 if (fi->fib_prefsrc == local) { 1277 fi->fib_flags |= RTNH_F_DEAD; 1278 ret++; 1279 } 1280 } 1281 return ret; 1282 } 1283 1284 int fib_sync_down_dev(struct net_device *dev, unsigned long event) 1285 { 1286 int ret = 0; 1287 int scope = RT_SCOPE_NOWHERE; 1288 struct fib_info *prev_fi = NULL; 1289 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1290 struct hlist_head *head = &fib_info_devhash[hash]; 1291 struct fib_nh *nh; 1292 1293 if (event == NETDEV_UNREGISTER || 1294 event == NETDEV_DOWN) 1295 scope = -1; 1296 1297 hlist_for_each_entry(nh, head, nh_hash) { 1298 struct fib_info *fi = nh->nh_parent; 1299 int dead; 1300 1301 BUG_ON(!fi->fib_nhs); 1302 if (nh->nh_dev != dev || fi == prev_fi) 1303 continue; 1304 prev_fi = fi; 1305 dead = 0; 1306 change_nexthops(fi) { 1307 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1308 dead++; 1309 else if (nexthop_nh->nh_dev == dev && 1310 nexthop_nh->nh_scope != scope) { 1311 switch (event) { 1312 case NETDEV_DOWN: 1313 case NETDEV_UNREGISTER: 1314 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1315 /* fall through */ 1316 case NETDEV_CHANGE: 1317 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1318 break; 1319 } 1320 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1321 spin_lock_bh(&fib_multipath_lock); 1322 fi->fib_power -= nexthop_nh->nh_power; 1323 nexthop_nh->nh_power = 0; 1324 spin_unlock_bh(&fib_multipath_lock); 1325 #endif 1326 dead++; 1327 } 1328 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1329 if (event == NETDEV_UNREGISTER && 1330 nexthop_nh->nh_dev == dev) { 1331 dead = fi->fib_nhs; 1332 break; 1333 } 1334 #endif 1335 } endfor_nexthops(fi) 1336 if (dead == fi->fib_nhs) { 1337 switch (event) { 1338 case NETDEV_DOWN: 1339 case NETDEV_UNREGISTER: 1340 fi->fib_flags |= RTNH_F_DEAD; 1341 /* fall through */ 1342 case NETDEV_CHANGE: 1343 fi->fib_flags |= RTNH_F_LINKDOWN; 1344 break; 1345 } 1346 ret++; 1347 } 1348 } 1349 1350 return ret; 1351 } 1352 1353 /* Must be invoked inside of an RCU protected region. */ 1354 void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1355 { 1356 struct fib_info *fi = NULL, *last_resort = NULL; 1357 struct hlist_head *fa_head = res->fa_head; 1358 struct fib_table *tb = res->table; 1359 u8 slen = 32 - res->prefixlen; 1360 int order = -1, last_idx = -1; 1361 struct fib_alias *fa, *fa1 = NULL; 1362 u32 last_prio = res->fi->fib_priority; 1363 u8 last_tos = 0; 1364 1365 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1366 struct fib_info *next_fi = fa->fa_info; 1367 1368 if (fa->fa_slen != slen) 1369 continue; 1370 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1371 continue; 1372 if (fa->tb_id != tb->tb_id) 1373 continue; 1374 if (next_fi->fib_priority > last_prio && 1375 fa->fa_tos == last_tos) { 1376 if (last_tos) 1377 continue; 1378 break; 1379 } 1380 if (next_fi->fib_flags & RTNH_F_DEAD) 1381 continue; 1382 last_tos = fa->fa_tos; 1383 last_prio = next_fi->fib_priority; 1384 1385 if (next_fi->fib_scope != res->scope || 1386 fa->fa_type != RTN_UNICAST) 1387 continue; 1388 if (!next_fi->fib_nh[0].nh_gw || 1389 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1390 continue; 1391 1392 fib_alias_accessed(fa); 1393 1394 if (!fi) { 1395 if (next_fi != res->fi) 1396 break; 1397 fa1 = fa; 1398 } else if (!fib_detect_death(fi, order, &last_resort, 1399 &last_idx, fa1->fa_default)) { 1400 fib_result_assign(res, fi); 1401 fa1->fa_default = order; 1402 goto out; 1403 } 1404 fi = next_fi; 1405 order++; 1406 } 1407 1408 if (order <= 0 || !fi) { 1409 if (fa1) 1410 fa1->fa_default = -1; 1411 goto out; 1412 } 1413 1414 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1415 fa1->fa_default)) { 1416 fib_result_assign(res, fi); 1417 fa1->fa_default = order; 1418 goto out; 1419 } 1420 1421 if (last_idx >= 0) 1422 fib_result_assign(res, last_resort); 1423 fa1->fa_default = last_idx; 1424 out: 1425 return; 1426 } 1427 1428 /* 1429 * Dead device goes up. We wake up dead nexthops. 1430 * It takes sense only on multipath routes. 1431 */ 1432 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1433 { 1434 struct fib_info *prev_fi; 1435 unsigned int hash; 1436 struct hlist_head *head; 1437 struct fib_nh *nh; 1438 int ret; 1439 1440 if (!(dev->flags & IFF_UP)) 1441 return 0; 1442 1443 prev_fi = NULL; 1444 hash = fib_devindex_hashfn(dev->ifindex); 1445 head = &fib_info_devhash[hash]; 1446 ret = 0; 1447 1448 hlist_for_each_entry(nh, head, nh_hash) { 1449 struct fib_info *fi = nh->nh_parent; 1450 int alive; 1451 1452 BUG_ON(!fi->fib_nhs); 1453 if (nh->nh_dev != dev || fi == prev_fi) 1454 continue; 1455 1456 prev_fi = fi; 1457 alive = 0; 1458 change_nexthops(fi) { 1459 if (!(nexthop_nh->nh_flags & nh_flags)) { 1460 alive++; 1461 continue; 1462 } 1463 if (!nexthop_nh->nh_dev || 1464 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1465 continue; 1466 if (nexthop_nh->nh_dev != dev || 1467 !__in_dev_get_rtnl(dev)) 1468 continue; 1469 alive++; 1470 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1471 spin_lock_bh(&fib_multipath_lock); 1472 nexthop_nh->nh_power = 0; 1473 nexthop_nh->nh_flags &= ~nh_flags; 1474 spin_unlock_bh(&fib_multipath_lock); 1475 #else 1476 nexthop_nh->nh_flags &= ~nh_flags; 1477 #endif 1478 } endfor_nexthops(fi) 1479 1480 if (alive > 0) { 1481 fi->fib_flags &= ~nh_flags; 1482 ret++; 1483 } 1484 } 1485 1486 return ret; 1487 } 1488 1489 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1490 1491 /* 1492 * The algorithm is suboptimal, but it provides really 1493 * fair weighted route distribution. 1494 */ 1495 void fib_select_multipath(struct fib_result *res) 1496 { 1497 struct fib_info *fi = res->fi; 1498 struct in_device *in_dev; 1499 int w; 1500 1501 spin_lock_bh(&fib_multipath_lock); 1502 if (fi->fib_power <= 0) { 1503 int power = 0; 1504 change_nexthops(fi) { 1505 in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev); 1506 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1507 continue; 1508 if (in_dev && 1509 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1510 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1511 continue; 1512 power += nexthop_nh->nh_weight; 1513 nexthop_nh->nh_power = nexthop_nh->nh_weight; 1514 } endfor_nexthops(fi); 1515 fi->fib_power = power; 1516 if (power <= 0) { 1517 spin_unlock_bh(&fib_multipath_lock); 1518 /* Race condition: route has just become dead. */ 1519 res->nh_sel = 0; 1520 return; 1521 } 1522 } 1523 1524 1525 /* w should be random number [0..fi->fib_power-1], 1526 * it is pretty bad approximation. 1527 */ 1528 1529 w = jiffies % fi->fib_power; 1530 1531 change_nexthops(fi) { 1532 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) && 1533 nexthop_nh->nh_power) { 1534 w -= nexthop_nh->nh_power; 1535 if (w <= 0) { 1536 nexthop_nh->nh_power--; 1537 fi->fib_power--; 1538 res->nh_sel = nhsel; 1539 spin_unlock_bh(&fib_multipath_lock); 1540 return; 1541 } 1542 } 1543 } endfor_nexthops(fi); 1544 1545 /* Race condition: route has just become dead. */ 1546 res->nh_sel = 0; 1547 spin_unlock_bh(&fib_multipath_lock); 1548 } 1549 #endif 1550