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 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 483 return -EINVAL; 484 485 nexthop_nh->nh_flags = 486 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 487 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 488 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 489 490 attrlen = rtnh_attrlen(rtnh); 491 if (attrlen > 0) { 492 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 493 494 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 495 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 496 #ifdef CONFIG_IP_ROUTE_CLASSID 497 nla = nla_find(attrs, attrlen, RTA_FLOW); 498 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 499 if (nexthop_nh->nh_tclassid) 500 fi->fib_net->ipv4.fib_num_tclassid_users++; 501 #endif 502 nla = nla_find(attrs, attrlen, RTA_ENCAP); 503 if (nla) { 504 struct lwtunnel_state *lwtstate; 505 struct net_device *dev = NULL; 506 struct nlattr *nla_entype; 507 508 nla_entype = nla_find(attrs, attrlen, 509 RTA_ENCAP_TYPE); 510 if (!nla_entype) 511 goto err_inval; 512 if (cfg->fc_oif) 513 dev = __dev_get_by_index(net, cfg->fc_oif); 514 ret = lwtunnel_build_state(dev, nla_get_u16( 515 nla_entype), 516 nla, AF_INET, cfg, 517 &lwtstate); 518 if (ret) 519 goto errout; 520 nexthop_nh->nh_lwtstate = 521 lwtstate_get(lwtstate); 522 } 523 } 524 525 rtnh = rtnh_next(rtnh, &remaining); 526 } endfor_nexthops(fi); 527 528 return 0; 529 530 err_inval: 531 ret = -EINVAL; 532 533 errout: 534 return ret; 535 } 536 537 static void fib_rebalance(struct fib_info *fi) 538 { 539 int total; 540 int w; 541 struct in_device *in_dev; 542 543 if (fi->fib_nhs < 2) 544 return; 545 546 total = 0; 547 for_nexthops(fi) { 548 if (nh->nh_flags & RTNH_F_DEAD) 549 continue; 550 551 in_dev = __in_dev_get_rtnl(nh->nh_dev); 552 553 if (in_dev && 554 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 555 nh->nh_flags & RTNH_F_LINKDOWN) 556 continue; 557 558 total += nh->nh_weight; 559 } endfor_nexthops(fi); 560 561 w = 0; 562 change_nexthops(fi) { 563 int upper_bound; 564 565 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev); 566 567 if (nexthop_nh->nh_flags & RTNH_F_DEAD) { 568 upper_bound = -1; 569 } else if (in_dev && 570 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 571 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) { 572 upper_bound = -1; 573 } else { 574 w += nexthop_nh->nh_weight; 575 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 576 total) - 1; 577 } 578 579 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound); 580 } endfor_nexthops(fi); 581 582 net_get_random_once(&fib_multipath_secret, 583 sizeof(fib_multipath_secret)); 584 } 585 586 static inline void fib_add_weight(struct fib_info *fi, 587 const struct fib_nh *nh) 588 { 589 fi->fib_weight += nh->nh_weight; 590 } 591 592 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 593 594 #define fib_rebalance(fi) do { } while (0) 595 #define fib_add_weight(fi, nh) do { } while (0) 596 597 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 598 599 static int fib_encap_match(struct net *net, u16 encap_type, 600 struct nlattr *encap, 601 int oif, const struct fib_nh *nh, 602 const struct fib_config *cfg) 603 { 604 struct lwtunnel_state *lwtstate; 605 struct net_device *dev = NULL; 606 int ret, result = 0; 607 608 if (encap_type == LWTUNNEL_ENCAP_NONE) 609 return 0; 610 611 if (oif) 612 dev = __dev_get_by_index(net, oif); 613 ret = lwtunnel_build_state(dev, encap_type, encap, 614 AF_INET, cfg, &lwtstate); 615 if (!ret) { 616 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 617 lwtstate_free(lwtstate); 618 } 619 620 return result; 621 } 622 623 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 624 { 625 struct net *net = cfg->fc_nlinfo.nl_net; 626 #ifdef CONFIG_IP_ROUTE_MULTIPATH 627 struct rtnexthop *rtnh; 628 int remaining; 629 #endif 630 631 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 632 return 1; 633 634 if (cfg->fc_oif || cfg->fc_gw) { 635 if (cfg->fc_encap) { 636 if (fib_encap_match(net, cfg->fc_encap_type, 637 cfg->fc_encap, cfg->fc_oif, 638 fi->fib_nh, cfg)) 639 return 1; 640 } 641 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 642 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 643 return 0; 644 return 1; 645 } 646 647 #ifdef CONFIG_IP_ROUTE_MULTIPATH 648 if (!cfg->fc_mp) 649 return 0; 650 651 rtnh = cfg->fc_mp; 652 remaining = cfg->fc_mp_len; 653 654 for_nexthops(fi) { 655 int attrlen; 656 657 if (!rtnh_ok(rtnh, remaining)) 658 return -EINVAL; 659 660 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 661 return 1; 662 663 attrlen = rtnh_attrlen(rtnh); 664 if (attrlen > 0) { 665 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 666 667 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 668 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 669 return 1; 670 #ifdef CONFIG_IP_ROUTE_CLASSID 671 nla = nla_find(attrs, attrlen, RTA_FLOW); 672 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 673 return 1; 674 #endif 675 } 676 677 rtnh = rtnh_next(rtnh, &remaining); 678 } endfor_nexthops(fi); 679 #endif 680 return 0; 681 } 682 683 684 /* 685 * Picture 686 * ------- 687 * 688 * Semantics of nexthop is very messy by historical reasons. 689 * We have to take into account, that: 690 * a) gateway can be actually local interface address, 691 * so that gatewayed route is direct. 692 * b) gateway must be on-link address, possibly 693 * described not by an ifaddr, but also by a direct route. 694 * c) If both gateway and interface are specified, they should not 695 * contradict. 696 * d) If we use tunnel routes, gateway could be not on-link. 697 * 698 * Attempt to reconcile all of these (alas, self-contradictory) conditions 699 * results in pretty ugly and hairy code with obscure logic. 700 * 701 * I chose to generalized it instead, so that the size 702 * of code does not increase practically, but it becomes 703 * much more general. 704 * Every prefix is assigned a "scope" value: "host" is local address, 705 * "link" is direct route, 706 * [ ... "site" ... "interior" ... ] 707 * and "universe" is true gateway route with global meaning. 708 * 709 * Every prefix refers to a set of "nexthop"s (gw, oif), 710 * where gw must have narrower scope. This recursion stops 711 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 712 * which means that gw is forced to be on link. 713 * 714 * Code is still hairy, but now it is apparently logically 715 * consistent and very flexible. F.e. as by-product it allows 716 * to co-exists in peace independent exterior and interior 717 * routing processes. 718 * 719 * Normally it looks as following. 720 * 721 * {universe prefix} -> (gw, oif) [scope link] 722 * | 723 * |-> {link prefix} -> (gw, oif) [scope local] 724 * | 725 * |-> {local prefix} (terminal node) 726 */ 727 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 728 struct fib_nh *nh) 729 { 730 int err = 0; 731 struct net *net; 732 struct net_device *dev; 733 734 net = cfg->fc_nlinfo.nl_net; 735 if (nh->nh_gw) { 736 struct fib_result res; 737 738 if (nh->nh_flags & RTNH_F_ONLINK) { 739 unsigned int addr_type; 740 741 if (cfg->fc_scope >= RT_SCOPE_LINK) 742 return -EINVAL; 743 dev = __dev_get_by_index(net, nh->nh_oif); 744 if (!dev) 745 return -ENODEV; 746 if (!(dev->flags & IFF_UP)) 747 return -ENETDOWN; 748 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 749 if (addr_type != RTN_UNICAST) 750 return -EINVAL; 751 if (!netif_carrier_ok(dev)) 752 nh->nh_flags |= RTNH_F_LINKDOWN; 753 nh->nh_dev = dev; 754 dev_hold(dev); 755 nh->nh_scope = RT_SCOPE_LINK; 756 return 0; 757 } 758 rcu_read_lock(); 759 { 760 struct fib_table *tbl = NULL; 761 struct flowi4 fl4 = { 762 .daddr = nh->nh_gw, 763 .flowi4_scope = cfg->fc_scope + 1, 764 .flowi4_oif = nh->nh_oif, 765 .flowi4_iif = LOOPBACK_IFINDEX, 766 }; 767 768 /* It is not necessary, but requires a bit of thinking */ 769 if (fl4.flowi4_scope < RT_SCOPE_LINK) 770 fl4.flowi4_scope = RT_SCOPE_LINK; 771 772 if (cfg->fc_table) 773 tbl = fib_get_table(net, cfg->fc_table); 774 775 if (tbl) 776 err = fib_table_lookup(tbl, &fl4, &res, 777 FIB_LOOKUP_IGNORE_LINKSTATE | 778 FIB_LOOKUP_NOREF); 779 780 /* on error or if no table given do full lookup. This 781 * is needed for example when nexthops are in the local 782 * table rather than the given table 783 */ 784 if (!tbl || err) { 785 err = fib_lookup(net, &fl4, &res, 786 FIB_LOOKUP_IGNORE_LINKSTATE); 787 } 788 789 if (err) { 790 rcu_read_unlock(); 791 return err; 792 } 793 } 794 err = -EINVAL; 795 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 796 goto out; 797 nh->nh_scope = res.scope; 798 nh->nh_oif = FIB_RES_OIF(res); 799 nh->nh_dev = dev = FIB_RES_DEV(res); 800 if (!dev) 801 goto out; 802 dev_hold(dev); 803 if (!netif_carrier_ok(dev)) 804 nh->nh_flags |= RTNH_F_LINKDOWN; 805 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 806 } else { 807 struct in_device *in_dev; 808 809 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 810 return -EINVAL; 811 812 rcu_read_lock(); 813 err = -ENODEV; 814 in_dev = inetdev_by_index(net, nh->nh_oif); 815 if (!in_dev) 816 goto out; 817 err = -ENETDOWN; 818 if (!(in_dev->dev->flags & IFF_UP)) 819 goto out; 820 nh->nh_dev = in_dev->dev; 821 dev_hold(nh->nh_dev); 822 nh->nh_scope = RT_SCOPE_HOST; 823 if (!netif_carrier_ok(nh->nh_dev)) 824 nh->nh_flags |= RTNH_F_LINKDOWN; 825 err = 0; 826 } 827 out: 828 rcu_read_unlock(); 829 return err; 830 } 831 832 static inline unsigned int fib_laddr_hashfn(__be32 val) 833 { 834 unsigned int mask = (fib_info_hash_size - 1); 835 836 return ((__force u32)val ^ 837 ((__force u32)val >> 7) ^ 838 ((__force u32)val >> 14)) & mask; 839 } 840 841 static struct hlist_head *fib_info_hash_alloc(int bytes) 842 { 843 if (bytes <= PAGE_SIZE) 844 return kzalloc(bytes, GFP_KERNEL); 845 else 846 return (struct hlist_head *) 847 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 848 get_order(bytes)); 849 } 850 851 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 852 { 853 if (!hash) 854 return; 855 856 if (bytes <= PAGE_SIZE) 857 kfree(hash); 858 else 859 free_pages((unsigned long) hash, get_order(bytes)); 860 } 861 862 static void fib_info_hash_move(struct hlist_head *new_info_hash, 863 struct hlist_head *new_laddrhash, 864 unsigned int new_size) 865 { 866 struct hlist_head *old_info_hash, *old_laddrhash; 867 unsigned int old_size = fib_info_hash_size; 868 unsigned int i, bytes; 869 870 spin_lock_bh(&fib_info_lock); 871 old_info_hash = fib_info_hash; 872 old_laddrhash = fib_info_laddrhash; 873 fib_info_hash_size = new_size; 874 875 for (i = 0; i < old_size; i++) { 876 struct hlist_head *head = &fib_info_hash[i]; 877 struct hlist_node *n; 878 struct fib_info *fi; 879 880 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 881 struct hlist_head *dest; 882 unsigned int new_hash; 883 884 new_hash = fib_info_hashfn(fi); 885 dest = &new_info_hash[new_hash]; 886 hlist_add_head(&fi->fib_hash, dest); 887 } 888 } 889 fib_info_hash = new_info_hash; 890 891 for (i = 0; i < old_size; i++) { 892 struct hlist_head *lhead = &fib_info_laddrhash[i]; 893 struct hlist_node *n; 894 struct fib_info *fi; 895 896 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 897 struct hlist_head *ldest; 898 unsigned int new_hash; 899 900 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 901 ldest = &new_laddrhash[new_hash]; 902 hlist_add_head(&fi->fib_lhash, ldest); 903 } 904 } 905 fib_info_laddrhash = new_laddrhash; 906 907 spin_unlock_bh(&fib_info_lock); 908 909 bytes = old_size * sizeof(struct hlist_head *); 910 fib_info_hash_free(old_info_hash, bytes); 911 fib_info_hash_free(old_laddrhash, bytes); 912 } 913 914 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 915 { 916 nh->nh_saddr = inet_select_addr(nh->nh_dev, 917 nh->nh_gw, 918 nh->nh_parent->fib_scope); 919 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 920 921 return nh->nh_saddr; 922 } 923 924 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 925 { 926 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 927 fib_prefsrc != cfg->fc_dst) { 928 u32 tb_id = cfg->fc_table; 929 int rc; 930 931 if (tb_id == RT_TABLE_MAIN) 932 tb_id = RT_TABLE_LOCAL; 933 934 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 935 fib_prefsrc, tb_id); 936 937 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 938 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 939 fib_prefsrc, RT_TABLE_LOCAL); 940 } 941 942 if (rc != RTN_LOCAL) 943 return false; 944 } 945 return true; 946 } 947 948 static int 949 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 950 { 951 bool ecn_ca = false; 952 struct nlattr *nla; 953 int remaining; 954 955 if (!cfg->fc_mx) 956 return 0; 957 958 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 959 int type = nla_type(nla); 960 u32 val; 961 962 if (!type) 963 continue; 964 if (type > RTAX_MAX) 965 return -EINVAL; 966 967 if (type == RTAX_CC_ALGO) { 968 char tmp[TCP_CA_NAME_MAX]; 969 970 nla_strlcpy(tmp, nla, sizeof(tmp)); 971 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 972 if (val == TCP_CA_UNSPEC) 973 return -EINVAL; 974 } else { 975 val = nla_get_u32(nla); 976 } 977 if (type == RTAX_ADVMSS && val > 65535 - 40) 978 val = 65535 - 40; 979 if (type == RTAX_MTU && val > 65535 - 15) 980 val = 65535 - 15; 981 if (type == RTAX_HOPLIMIT && val > 255) 982 val = 255; 983 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 984 return -EINVAL; 985 fi->fib_metrics[type - 1] = val; 986 } 987 988 if (ecn_ca) 989 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 990 991 return 0; 992 } 993 994 struct fib_info *fib_create_info(struct fib_config *cfg) 995 { 996 int err; 997 struct fib_info *fi = NULL; 998 struct fib_info *ofi; 999 int nhs = 1; 1000 struct net *net = cfg->fc_nlinfo.nl_net; 1001 1002 if (cfg->fc_type > RTN_MAX) 1003 goto err_inval; 1004 1005 /* Fast check to catch the most weird cases */ 1006 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 1007 goto err_inval; 1008 1009 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 1010 goto err_inval; 1011 1012 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1013 if (cfg->fc_mp) { 1014 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 1015 if (nhs == 0) 1016 goto err_inval; 1017 } 1018 #endif 1019 1020 err = -ENOBUFS; 1021 if (fib_info_cnt >= fib_info_hash_size) { 1022 unsigned int new_size = fib_info_hash_size << 1; 1023 struct hlist_head *new_info_hash; 1024 struct hlist_head *new_laddrhash; 1025 unsigned int bytes; 1026 1027 if (!new_size) 1028 new_size = 16; 1029 bytes = new_size * sizeof(struct hlist_head *); 1030 new_info_hash = fib_info_hash_alloc(bytes); 1031 new_laddrhash = fib_info_hash_alloc(bytes); 1032 if (!new_info_hash || !new_laddrhash) { 1033 fib_info_hash_free(new_info_hash, bytes); 1034 fib_info_hash_free(new_laddrhash, bytes); 1035 } else 1036 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1037 1038 if (!fib_info_hash_size) 1039 goto failure; 1040 } 1041 1042 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1043 if (!fi) 1044 goto failure; 1045 fib_info_cnt++; 1046 if (cfg->fc_mx) { 1047 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 1048 if (!fi->fib_metrics) 1049 goto failure; 1050 } else 1051 fi->fib_metrics = (u32 *) dst_default_metrics; 1052 1053 fi->fib_net = net; 1054 fi->fib_protocol = cfg->fc_protocol; 1055 fi->fib_scope = cfg->fc_scope; 1056 fi->fib_flags = cfg->fc_flags; 1057 fi->fib_priority = cfg->fc_priority; 1058 fi->fib_prefsrc = cfg->fc_prefsrc; 1059 fi->fib_type = cfg->fc_type; 1060 1061 fi->fib_nhs = nhs; 1062 change_nexthops(fi) { 1063 nexthop_nh->nh_parent = fi; 1064 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1065 if (!nexthop_nh->nh_pcpu_rth_output) 1066 goto failure; 1067 } endfor_nexthops(fi) 1068 1069 err = fib_convert_metrics(fi, cfg); 1070 if (err) 1071 goto failure; 1072 1073 if (cfg->fc_mp) { 1074 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1075 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 1076 if (err != 0) 1077 goto failure; 1078 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 1079 goto err_inval; 1080 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 1081 goto err_inval; 1082 #ifdef CONFIG_IP_ROUTE_CLASSID 1083 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 1084 goto err_inval; 1085 #endif 1086 #else 1087 goto err_inval; 1088 #endif 1089 } else { 1090 struct fib_nh *nh = fi->fib_nh; 1091 1092 if (cfg->fc_encap) { 1093 struct lwtunnel_state *lwtstate; 1094 struct net_device *dev = NULL; 1095 1096 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) 1097 goto err_inval; 1098 if (cfg->fc_oif) 1099 dev = __dev_get_by_index(net, cfg->fc_oif); 1100 err = lwtunnel_build_state(dev, cfg->fc_encap_type, 1101 cfg->fc_encap, AF_INET, cfg, 1102 &lwtstate); 1103 if (err) 1104 goto failure; 1105 1106 nh->nh_lwtstate = lwtstate_get(lwtstate); 1107 } 1108 nh->nh_oif = cfg->fc_oif; 1109 nh->nh_gw = cfg->fc_gw; 1110 nh->nh_flags = cfg->fc_flags; 1111 #ifdef CONFIG_IP_ROUTE_CLASSID 1112 nh->nh_tclassid = cfg->fc_flow; 1113 if (nh->nh_tclassid) 1114 fi->fib_net->ipv4.fib_num_tclassid_users++; 1115 #endif 1116 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1117 nh->nh_weight = 1; 1118 #endif 1119 } 1120 1121 if (fib_props[cfg->fc_type].error) { 1122 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 1123 goto err_inval; 1124 goto link_it; 1125 } else { 1126 switch (cfg->fc_type) { 1127 case RTN_UNICAST: 1128 case RTN_LOCAL: 1129 case RTN_BROADCAST: 1130 case RTN_ANYCAST: 1131 case RTN_MULTICAST: 1132 break; 1133 default: 1134 goto err_inval; 1135 } 1136 } 1137 1138 if (cfg->fc_scope > RT_SCOPE_HOST) 1139 goto err_inval; 1140 1141 if (cfg->fc_scope == RT_SCOPE_HOST) { 1142 struct fib_nh *nh = fi->fib_nh; 1143 1144 /* Local address is added. */ 1145 if (nhs != 1 || nh->nh_gw) 1146 goto err_inval; 1147 nh->nh_scope = RT_SCOPE_NOWHERE; 1148 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1149 err = -ENODEV; 1150 if (!nh->nh_dev) 1151 goto failure; 1152 } else { 1153 int linkdown = 0; 1154 1155 change_nexthops(fi) { 1156 err = fib_check_nh(cfg, fi, nexthop_nh); 1157 if (err != 0) 1158 goto failure; 1159 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1160 linkdown++; 1161 } endfor_nexthops(fi) 1162 if (linkdown == fi->fib_nhs) 1163 fi->fib_flags |= RTNH_F_LINKDOWN; 1164 } 1165 1166 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) 1167 goto err_inval; 1168 1169 change_nexthops(fi) { 1170 fib_info_update_nh_saddr(net, nexthop_nh); 1171 fib_add_weight(fi, nexthop_nh); 1172 } endfor_nexthops(fi) 1173 1174 fib_rebalance(fi); 1175 1176 link_it: 1177 ofi = fib_find_info(fi); 1178 if (ofi) { 1179 fi->fib_dead = 1; 1180 free_fib_info(fi); 1181 ofi->fib_treeref++; 1182 return ofi; 1183 } 1184 1185 fi->fib_treeref++; 1186 atomic_inc(&fi->fib_clntref); 1187 spin_lock_bh(&fib_info_lock); 1188 hlist_add_head(&fi->fib_hash, 1189 &fib_info_hash[fib_info_hashfn(fi)]); 1190 if (fi->fib_prefsrc) { 1191 struct hlist_head *head; 1192 1193 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1194 hlist_add_head(&fi->fib_lhash, head); 1195 } 1196 change_nexthops(fi) { 1197 struct hlist_head *head; 1198 unsigned int hash; 1199 1200 if (!nexthop_nh->nh_dev) 1201 continue; 1202 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1203 head = &fib_info_devhash[hash]; 1204 hlist_add_head(&nexthop_nh->nh_hash, head); 1205 } endfor_nexthops(fi) 1206 spin_unlock_bh(&fib_info_lock); 1207 return fi; 1208 1209 err_inval: 1210 err = -EINVAL; 1211 1212 failure: 1213 if (fi) { 1214 fi->fib_dead = 1; 1215 free_fib_info(fi); 1216 } 1217 1218 return ERR_PTR(err); 1219 } 1220 1221 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1222 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1223 struct fib_info *fi, unsigned int flags) 1224 { 1225 struct nlmsghdr *nlh; 1226 struct rtmsg *rtm; 1227 1228 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1229 if (!nlh) 1230 return -EMSGSIZE; 1231 1232 rtm = nlmsg_data(nlh); 1233 rtm->rtm_family = AF_INET; 1234 rtm->rtm_dst_len = dst_len; 1235 rtm->rtm_src_len = 0; 1236 rtm->rtm_tos = tos; 1237 if (tb_id < 256) 1238 rtm->rtm_table = tb_id; 1239 else 1240 rtm->rtm_table = RT_TABLE_COMPAT; 1241 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1242 goto nla_put_failure; 1243 rtm->rtm_type = type; 1244 rtm->rtm_flags = fi->fib_flags; 1245 rtm->rtm_scope = fi->fib_scope; 1246 rtm->rtm_protocol = fi->fib_protocol; 1247 1248 if (rtm->rtm_dst_len && 1249 nla_put_in_addr(skb, RTA_DST, dst)) 1250 goto nla_put_failure; 1251 if (fi->fib_priority && 1252 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1253 goto nla_put_failure; 1254 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1255 goto nla_put_failure; 1256 1257 if (fi->fib_prefsrc && 1258 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1259 goto nla_put_failure; 1260 if (fi->fib_nhs == 1) { 1261 struct in_device *in_dev; 1262 1263 if (fi->fib_nh->nh_gw && 1264 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1265 goto nla_put_failure; 1266 if (fi->fib_nh->nh_oif && 1267 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1268 goto nla_put_failure; 1269 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1270 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1271 if (in_dev && 1272 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1273 rtm->rtm_flags |= RTNH_F_DEAD; 1274 } 1275 #ifdef CONFIG_IP_ROUTE_CLASSID 1276 if (fi->fib_nh[0].nh_tclassid && 1277 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1278 goto nla_put_failure; 1279 #endif 1280 if (fi->fib_nh->nh_lwtstate) 1281 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate); 1282 } 1283 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1284 if (fi->fib_nhs > 1) { 1285 struct rtnexthop *rtnh; 1286 struct nlattr *mp; 1287 1288 mp = nla_nest_start(skb, RTA_MULTIPATH); 1289 if (!mp) 1290 goto nla_put_failure; 1291 1292 for_nexthops(fi) { 1293 struct in_device *in_dev; 1294 1295 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1296 if (!rtnh) 1297 goto nla_put_failure; 1298 1299 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1300 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1301 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1302 if (in_dev && 1303 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1304 rtnh->rtnh_flags |= RTNH_F_DEAD; 1305 } 1306 rtnh->rtnh_hops = nh->nh_weight - 1; 1307 rtnh->rtnh_ifindex = nh->nh_oif; 1308 1309 if (nh->nh_gw && 1310 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1311 goto nla_put_failure; 1312 #ifdef CONFIG_IP_ROUTE_CLASSID 1313 if (nh->nh_tclassid && 1314 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1315 goto nla_put_failure; 1316 #endif 1317 if (nh->nh_lwtstate) 1318 lwtunnel_fill_encap(skb, nh->nh_lwtstate); 1319 /* length of rtnetlink header + attributes */ 1320 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1321 } endfor_nexthops(fi); 1322 1323 nla_nest_end(skb, mp); 1324 } 1325 #endif 1326 nlmsg_end(skb, nlh); 1327 return 0; 1328 1329 nla_put_failure: 1330 nlmsg_cancel(skb, nlh); 1331 return -EMSGSIZE; 1332 } 1333 1334 /* 1335 * Update FIB if: 1336 * - local address disappeared -> we must delete all the entries 1337 * referring to it. 1338 * - device went down -> we must shutdown all nexthops going via it. 1339 */ 1340 int fib_sync_down_addr(struct net *net, __be32 local) 1341 { 1342 int ret = 0; 1343 unsigned int hash = fib_laddr_hashfn(local); 1344 struct hlist_head *head = &fib_info_laddrhash[hash]; 1345 struct fib_info *fi; 1346 1347 if (!fib_info_laddrhash || local == 0) 1348 return 0; 1349 1350 hlist_for_each_entry(fi, head, fib_lhash) { 1351 if (!net_eq(fi->fib_net, net)) 1352 continue; 1353 if (fi->fib_prefsrc == local) { 1354 fi->fib_flags |= RTNH_F_DEAD; 1355 ret++; 1356 } 1357 } 1358 return ret; 1359 } 1360 1361 /* Event force Flags Description 1362 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1363 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1364 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1365 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1366 */ 1367 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1368 { 1369 int ret = 0; 1370 int scope = RT_SCOPE_NOWHERE; 1371 struct fib_info *prev_fi = NULL; 1372 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1373 struct hlist_head *head = &fib_info_devhash[hash]; 1374 struct fib_nh *nh; 1375 1376 if (force) 1377 scope = -1; 1378 1379 hlist_for_each_entry(nh, head, nh_hash) { 1380 struct fib_info *fi = nh->nh_parent; 1381 int dead; 1382 1383 BUG_ON(!fi->fib_nhs); 1384 if (nh->nh_dev != dev || fi == prev_fi) 1385 continue; 1386 prev_fi = fi; 1387 dead = 0; 1388 change_nexthops(fi) { 1389 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1390 dead++; 1391 else if (nexthop_nh->nh_dev == dev && 1392 nexthop_nh->nh_scope != scope) { 1393 switch (event) { 1394 case NETDEV_DOWN: 1395 case NETDEV_UNREGISTER: 1396 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1397 /* fall through */ 1398 case NETDEV_CHANGE: 1399 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1400 break; 1401 } 1402 dead++; 1403 } 1404 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1405 if (event == NETDEV_UNREGISTER && 1406 nexthop_nh->nh_dev == dev) { 1407 dead = fi->fib_nhs; 1408 break; 1409 } 1410 #endif 1411 } endfor_nexthops(fi) 1412 if (dead == fi->fib_nhs) { 1413 switch (event) { 1414 case NETDEV_DOWN: 1415 case NETDEV_UNREGISTER: 1416 fi->fib_flags |= RTNH_F_DEAD; 1417 /* fall through */ 1418 case NETDEV_CHANGE: 1419 fi->fib_flags |= RTNH_F_LINKDOWN; 1420 break; 1421 } 1422 ret++; 1423 } 1424 1425 fib_rebalance(fi); 1426 } 1427 1428 return ret; 1429 } 1430 1431 /* Must be invoked inside of an RCU protected region. */ 1432 void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1433 { 1434 struct fib_info *fi = NULL, *last_resort = NULL; 1435 struct hlist_head *fa_head = res->fa_head; 1436 struct fib_table *tb = res->table; 1437 u8 slen = 32 - res->prefixlen; 1438 int order = -1, last_idx = -1; 1439 struct fib_alias *fa, *fa1 = NULL; 1440 u32 last_prio = res->fi->fib_priority; 1441 u8 last_tos = 0; 1442 1443 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1444 struct fib_info *next_fi = fa->fa_info; 1445 1446 if (fa->fa_slen != slen) 1447 continue; 1448 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1449 continue; 1450 if (fa->tb_id != tb->tb_id) 1451 continue; 1452 if (next_fi->fib_priority > last_prio && 1453 fa->fa_tos == last_tos) { 1454 if (last_tos) 1455 continue; 1456 break; 1457 } 1458 if (next_fi->fib_flags & RTNH_F_DEAD) 1459 continue; 1460 last_tos = fa->fa_tos; 1461 last_prio = next_fi->fib_priority; 1462 1463 if (next_fi->fib_scope != res->scope || 1464 fa->fa_type != RTN_UNICAST) 1465 continue; 1466 if (!next_fi->fib_nh[0].nh_gw || 1467 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1468 continue; 1469 1470 fib_alias_accessed(fa); 1471 1472 if (!fi) { 1473 if (next_fi != res->fi) 1474 break; 1475 fa1 = fa; 1476 } else if (!fib_detect_death(fi, order, &last_resort, 1477 &last_idx, fa1->fa_default)) { 1478 fib_result_assign(res, fi); 1479 fa1->fa_default = order; 1480 goto out; 1481 } 1482 fi = next_fi; 1483 order++; 1484 } 1485 1486 if (order <= 0 || !fi) { 1487 if (fa1) 1488 fa1->fa_default = -1; 1489 goto out; 1490 } 1491 1492 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1493 fa1->fa_default)) { 1494 fib_result_assign(res, fi); 1495 fa1->fa_default = order; 1496 goto out; 1497 } 1498 1499 if (last_idx >= 0) 1500 fib_result_assign(res, last_resort); 1501 fa1->fa_default = last_idx; 1502 out: 1503 return; 1504 } 1505 1506 /* 1507 * Dead device goes up. We wake up dead nexthops. 1508 * It takes sense only on multipath routes. 1509 */ 1510 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1511 { 1512 struct fib_info *prev_fi; 1513 unsigned int hash; 1514 struct hlist_head *head; 1515 struct fib_nh *nh; 1516 int ret; 1517 1518 if (!(dev->flags & IFF_UP)) 1519 return 0; 1520 1521 if (nh_flags & RTNH_F_DEAD) { 1522 unsigned int flags = dev_get_flags(dev); 1523 1524 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1525 nh_flags |= RTNH_F_LINKDOWN; 1526 } 1527 1528 prev_fi = NULL; 1529 hash = fib_devindex_hashfn(dev->ifindex); 1530 head = &fib_info_devhash[hash]; 1531 ret = 0; 1532 1533 hlist_for_each_entry(nh, head, nh_hash) { 1534 struct fib_info *fi = nh->nh_parent; 1535 int alive; 1536 1537 BUG_ON(!fi->fib_nhs); 1538 if (nh->nh_dev != dev || fi == prev_fi) 1539 continue; 1540 1541 prev_fi = fi; 1542 alive = 0; 1543 change_nexthops(fi) { 1544 if (!(nexthop_nh->nh_flags & nh_flags)) { 1545 alive++; 1546 continue; 1547 } 1548 if (!nexthop_nh->nh_dev || 1549 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1550 continue; 1551 if (nexthop_nh->nh_dev != dev || 1552 !__in_dev_get_rtnl(dev)) 1553 continue; 1554 alive++; 1555 nexthop_nh->nh_flags &= ~nh_flags; 1556 } endfor_nexthops(fi) 1557 1558 if (alive > 0) { 1559 fi->fib_flags &= ~nh_flags; 1560 ret++; 1561 } 1562 1563 fib_rebalance(fi); 1564 } 1565 1566 return ret; 1567 } 1568 1569 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1570 static bool fib_good_nh(const struct fib_nh *nh) 1571 { 1572 int state = NUD_REACHABLE; 1573 1574 if (nh->nh_scope == RT_SCOPE_LINK) { 1575 struct neighbour *n; 1576 1577 rcu_read_lock_bh(); 1578 1579 n = __ipv4_neigh_lookup_noref(nh->nh_dev, nh->nh_gw); 1580 if (n) 1581 state = n->nud_state; 1582 1583 rcu_read_unlock_bh(); 1584 } 1585 1586 return !!(state & NUD_VALID); 1587 } 1588 1589 void fib_select_multipath(struct fib_result *res, int hash) 1590 { 1591 struct fib_info *fi = res->fi; 1592 struct net *net = fi->fib_net; 1593 bool first = false; 1594 1595 for_nexthops(fi) { 1596 if (hash > atomic_read(&nh->nh_upper_bound)) 1597 continue; 1598 1599 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1600 fib_good_nh(nh)) { 1601 res->nh_sel = nhsel; 1602 return; 1603 } 1604 if (!first) { 1605 res->nh_sel = nhsel; 1606 first = true; 1607 } 1608 } endfor_nexthops(fi); 1609 } 1610 #endif 1611 1612 void fib_select_path(struct net *net, struct fib_result *res, 1613 struct flowi4 *fl4, int mp_hash) 1614 { 1615 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1616 if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) { 1617 if (mp_hash < 0) 1618 mp_hash = get_hash_from_flowi4(fl4) >> 1; 1619 1620 fib_select_multipath(res, mp_hash); 1621 } 1622 else 1623 #endif 1624 if (!res->prefixlen && 1625 res->table->tb_num_default > 1 && 1626 res->type == RTN_UNICAST && !fl4->flowi4_oif) 1627 fib_select_default(fl4, res); 1628 1629 if (!fl4->saddr) 1630 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1631 } 1632 EXPORT_SYMBOL_GPL(fib_select_path); 1633