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