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