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 <linux/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 EXPORT_SYMBOL_GPL(free_fib_info); 238 239 void fib_release_info(struct fib_info *fi) 240 { 241 spin_lock_bh(&fib_info_lock); 242 if (fi && --fi->fib_treeref == 0) { 243 hlist_del(&fi->fib_hash); 244 if (fi->fib_prefsrc) 245 hlist_del(&fi->fib_lhash); 246 change_nexthops(fi) { 247 if (!nexthop_nh->nh_dev) 248 continue; 249 hlist_del(&nexthop_nh->nh_hash); 250 } endfor_nexthops(fi) 251 fi->fib_dead = 1; 252 fib_info_put(fi); 253 } 254 spin_unlock_bh(&fib_info_lock); 255 } 256 257 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 258 { 259 const struct fib_nh *onh = ofi->fib_nh; 260 261 for_nexthops(fi) { 262 if (nh->nh_oif != onh->nh_oif || 263 nh->nh_gw != onh->nh_gw || 264 nh->nh_scope != onh->nh_scope || 265 #ifdef CONFIG_IP_ROUTE_MULTIPATH 266 nh->nh_weight != onh->nh_weight || 267 #endif 268 #ifdef CONFIG_IP_ROUTE_CLASSID 269 nh->nh_tclassid != onh->nh_tclassid || 270 #endif 271 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) || 272 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK)) 273 return -1; 274 onh++; 275 } endfor_nexthops(fi); 276 return 0; 277 } 278 279 static inline unsigned int fib_devindex_hashfn(unsigned int val) 280 { 281 unsigned int mask = DEVINDEX_HASHSIZE - 1; 282 283 return (val ^ 284 (val >> DEVINDEX_HASHBITS) ^ 285 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 286 } 287 288 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 289 { 290 unsigned int mask = (fib_info_hash_size - 1); 291 unsigned int val = fi->fib_nhs; 292 293 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 294 val ^= (__force u32)fi->fib_prefsrc; 295 val ^= fi->fib_priority; 296 for_nexthops(fi) { 297 val ^= fib_devindex_hashfn(nh->nh_oif); 298 } endfor_nexthops(fi) 299 300 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 301 } 302 303 static struct fib_info *fib_find_info(const struct fib_info *nfi) 304 { 305 struct hlist_head *head; 306 struct fib_info *fi; 307 unsigned int hash; 308 309 hash = fib_info_hashfn(nfi); 310 head = &fib_info_hash[hash]; 311 312 hlist_for_each_entry(fi, head, fib_hash) { 313 if (!net_eq(fi->fib_net, nfi->fib_net)) 314 continue; 315 if (fi->fib_nhs != nfi->fib_nhs) 316 continue; 317 if (nfi->fib_protocol == fi->fib_protocol && 318 nfi->fib_scope == fi->fib_scope && 319 nfi->fib_prefsrc == fi->fib_prefsrc && 320 nfi->fib_priority == fi->fib_priority && 321 nfi->fib_type == fi->fib_type && 322 memcmp(nfi->fib_metrics, fi->fib_metrics, 323 sizeof(u32) * RTAX_MAX) == 0 && 324 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 325 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 326 return fi; 327 } 328 329 return NULL; 330 } 331 332 /* Check, that the gateway is already configured. 333 * Used only by redirect accept routine. 334 */ 335 int ip_fib_check_default(__be32 gw, struct net_device *dev) 336 { 337 struct hlist_head *head; 338 struct fib_nh *nh; 339 unsigned int hash; 340 341 spin_lock(&fib_info_lock); 342 343 hash = fib_devindex_hashfn(dev->ifindex); 344 head = &fib_info_devhash[hash]; 345 hlist_for_each_entry(nh, head, nh_hash) { 346 if (nh->nh_dev == dev && 347 nh->nh_gw == gw && 348 !(nh->nh_flags & RTNH_F_DEAD)) { 349 spin_unlock(&fib_info_lock); 350 return 0; 351 } 352 } 353 354 spin_unlock(&fib_info_lock); 355 356 return -1; 357 } 358 359 static inline size_t fib_nlmsg_size(struct fib_info *fi) 360 { 361 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 362 + nla_total_size(4) /* RTA_TABLE */ 363 + nla_total_size(4) /* RTA_DST */ 364 + nla_total_size(4) /* RTA_PRIORITY */ 365 + nla_total_size(4) /* RTA_PREFSRC */ 366 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 367 368 /* space for nested metrics */ 369 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 370 371 if (fi->fib_nhs) { 372 size_t nh_encapsize = 0; 373 /* Also handles the special case fib_nhs == 1 */ 374 375 /* each nexthop is packed in an attribute */ 376 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 377 378 /* may contain flow and gateway attribute */ 379 nhsize += 2 * nla_total_size(4); 380 381 /* grab encap info */ 382 for_nexthops(fi) { 383 if (nh->nh_lwtstate) { 384 /* RTA_ENCAP_TYPE */ 385 nh_encapsize += lwtunnel_get_encap_size( 386 nh->nh_lwtstate); 387 /* RTA_ENCAP */ 388 nh_encapsize += nla_total_size(2); 389 } 390 } endfor_nexthops(fi); 391 392 /* all nexthops are packed in a nested attribute */ 393 payload += nla_total_size((fi->fib_nhs * nhsize) + 394 nh_encapsize); 395 396 } 397 398 return payload; 399 } 400 401 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 402 int dst_len, u32 tb_id, const struct nl_info *info, 403 unsigned int nlm_flags) 404 { 405 struct sk_buff *skb; 406 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 407 int err = -ENOBUFS; 408 409 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 410 if (!skb) 411 goto errout; 412 413 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 414 fa->fa_type, key, dst_len, 415 fa->fa_tos, fa->fa_info, nlm_flags); 416 if (err < 0) { 417 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 418 WARN_ON(err == -EMSGSIZE); 419 kfree_skb(skb); 420 goto errout; 421 } 422 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 423 info->nlh, GFP_KERNEL); 424 return; 425 errout: 426 if (err < 0) 427 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 428 } 429 430 static int fib_detect_death(struct fib_info *fi, int order, 431 struct fib_info **last_resort, int *last_idx, 432 int dflt) 433 { 434 struct neighbour *n; 435 int state = NUD_NONE; 436 437 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); 438 if (n) { 439 state = n->nud_state; 440 neigh_release(n); 441 } else { 442 return 0; 443 } 444 if (state == NUD_REACHABLE) 445 return 0; 446 if ((state & NUD_VALID) && order != dflt) 447 return 0; 448 if ((state & NUD_VALID) || 449 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 450 *last_resort = fi; 451 *last_idx = order; 452 } 453 return 1; 454 } 455 456 #ifdef CONFIG_IP_ROUTE_MULTIPATH 457 458 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining) 459 { 460 int nhs = 0; 461 462 while (rtnh_ok(rtnh, remaining)) { 463 nhs++; 464 rtnh = rtnh_next(rtnh, &remaining); 465 } 466 467 /* leftover implies invalid nexthop configuration, discard it */ 468 return remaining > 0 ? 0 : nhs; 469 } 470 471 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 472 int remaining, struct fib_config *cfg) 473 { 474 struct net *net = cfg->fc_nlinfo.nl_net; 475 int ret; 476 477 change_nexthops(fi) { 478 int attrlen; 479 480 if (!rtnh_ok(rtnh, remaining)) 481 return -EINVAL; 482 483 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 484 return -EINVAL; 485 486 nexthop_nh->nh_flags = 487 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 488 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 489 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 490 491 attrlen = rtnh_attrlen(rtnh); 492 if (attrlen > 0) { 493 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 494 495 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 496 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 497 #ifdef CONFIG_IP_ROUTE_CLASSID 498 nla = nla_find(attrs, attrlen, RTA_FLOW); 499 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 500 if (nexthop_nh->nh_tclassid) 501 fi->fib_net->ipv4.fib_num_tclassid_users++; 502 #endif 503 nla = nla_find(attrs, attrlen, RTA_ENCAP); 504 if (nla) { 505 struct lwtunnel_state *lwtstate; 506 struct net_device *dev = NULL; 507 struct nlattr *nla_entype; 508 509 nla_entype = nla_find(attrs, attrlen, 510 RTA_ENCAP_TYPE); 511 if (!nla_entype) 512 goto err_inval; 513 if (cfg->fc_oif) 514 dev = __dev_get_by_index(net, cfg->fc_oif); 515 ret = lwtunnel_build_state(dev, nla_get_u16( 516 nla_entype), 517 nla, AF_INET, cfg, 518 &lwtstate); 519 if (ret) 520 goto errout; 521 nexthop_nh->nh_lwtstate = 522 lwtstate_get(lwtstate); 523 } 524 } 525 526 rtnh = rtnh_next(rtnh, &remaining); 527 } endfor_nexthops(fi); 528 529 return 0; 530 531 err_inval: 532 ret = -EINVAL; 533 534 errout: 535 return ret; 536 } 537 538 static void fib_rebalance(struct fib_info *fi) 539 { 540 int total; 541 int w; 542 struct in_device *in_dev; 543 544 if (fi->fib_nhs < 2) 545 return; 546 547 total = 0; 548 for_nexthops(fi) { 549 if (nh->nh_flags & RTNH_F_DEAD) 550 continue; 551 552 in_dev = __in_dev_get_rtnl(nh->nh_dev); 553 554 if (in_dev && 555 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 556 nh->nh_flags & RTNH_F_LINKDOWN) 557 continue; 558 559 total += nh->nh_weight; 560 } endfor_nexthops(fi); 561 562 w = 0; 563 change_nexthops(fi) { 564 int upper_bound; 565 566 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev); 567 568 if (nexthop_nh->nh_flags & RTNH_F_DEAD) { 569 upper_bound = -1; 570 } else if (in_dev && 571 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 572 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) { 573 upper_bound = -1; 574 } else { 575 w += nexthop_nh->nh_weight; 576 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 577 total) - 1; 578 } 579 580 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound); 581 } endfor_nexthops(fi); 582 583 net_get_random_once(&fib_multipath_secret, 584 sizeof(fib_multipath_secret)); 585 } 586 587 static inline void fib_add_weight(struct fib_info *fi, 588 const struct fib_nh *nh) 589 { 590 fi->fib_weight += nh->nh_weight; 591 } 592 593 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 594 595 #define fib_rebalance(fi) do { } while (0) 596 #define fib_add_weight(fi, nh) do { } while (0) 597 598 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 599 600 static int fib_encap_match(struct net *net, u16 encap_type, 601 struct nlattr *encap, 602 int oif, const struct fib_nh *nh, 603 const struct fib_config *cfg) 604 { 605 struct lwtunnel_state *lwtstate; 606 struct net_device *dev = NULL; 607 int ret, result = 0; 608 609 if (encap_type == LWTUNNEL_ENCAP_NONE) 610 return 0; 611 612 if (oif) 613 dev = __dev_get_by_index(net, oif); 614 ret = lwtunnel_build_state(dev, encap_type, encap, 615 AF_INET, cfg, &lwtstate); 616 if (!ret) { 617 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 618 lwtstate_free(lwtstate); 619 } 620 621 return result; 622 } 623 624 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 625 { 626 struct net *net = cfg->fc_nlinfo.nl_net; 627 #ifdef CONFIG_IP_ROUTE_MULTIPATH 628 struct rtnexthop *rtnh; 629 int remaining; 630 #endif 631 632 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 633 return 1; 634 635 if (cfg->fc_oif || cfg->fc_gw) { 636 if (cfg->fc_encap) { 637 if (fib_encap_match(net, cfg->fc_encap_type, 638 cfg->fc_encap, cfg->fc_oif, 639 fi->fib_nh, cfg)) 640 return 1; 641 } 642 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 643 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 644 return 0; 645 return 1; 646 } 647 648 #ifdef CONFIG_IP_ROUTE_MULTIPATH 649 if (!cfg->fc_mp) 650 return 0; 651 652 rtnh = cfg->fc_mp; 653 remaining = cfg->fc_mp_len; 654 655 for_nexthops(fi) { 656 int attrlen; 657 658 if (!rtnh_ok(rtnh, remaining)) 659 return -EINVAL; 660 661 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 662 return 1; 663 664 attrlen = rtnh_attrlen(rtnh); 665 if (attrlen > 0) { 666 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 667 668 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 669 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 670 return 1; 671 #ifdef CONFIG_IP_ROUTE_CLASSID 672 nla = nla_find(attrs, attrlen, RTA_FLOW); 673 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 674 return 1; 675 #endif 676 } 677 678 rtnh = rtnh_next(rtnh, &remaining); 679 } endfor_nexthops(fi); 680 #endif 681 return 0; 682 } 683 684 685 /* 686 * Picture 687 * ------- 688 * 689 * Semantics of nexthop is very messy by historical reasons. 690 * We have to take into account, that: 691 * a) gateway can be actually local interface address, 692 * so that gatewayed route is direct. 693 * b) gateway must be on-link address, possibly 694 * described not by an ifaddr, but also by a direct route. 695 * c) If both gateway and interface are specified, they should not 696 * contradict. 697 * d) If we use tunnel routes, gateway could be not on-link. 698 * 699 * Attempt to reconcile all of these (alas, self-contradictory) conditions 700 * results in pretty ugly and hairy code with obscure logic. 701 * 702 * I chose to generalized it instead, so that the size 703 * of code does not increase practically, but it becomes 704 * much more general. 705 * Every prefix is assigned a "scope" value: "host" is local address, 706 * "link" is direct route, 707 * [ ... "site" ... "interior" ... ] 708 * and "universe" is true gateway route with global meaning. 709 * 710 * Every prefix refers to a set of "nexthop"s (gw, oif), 711 * where gw must have narrower scope. This recursion stops 712 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 713 * which means that gw is forced to be on link. 714 * 715 * Code is still hairy, but now it is apparently logically 716 * consistent and very flexible. F.e. as by-product it allows 717 * to co-exists in peace independent exterior and interior 718 * routing processes. 719 * 720 * Normally it looks as following. 721 * 722 * {universe prefix} -> (gw, oif) [scope link] 723 * | 724 * |-> {link prefix} -> (gw, oif) [scope local] 725 * | 726 * |-> {local prefix} (terminal node) 727 */ 728 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 729 struct fib_nh *nh) 730 { 731 int err = 0; 732 struct net *net; 733 struct net_device *dev; 734 735 net = cfg->fc_nlinfo.nl_net; 736 if (nh->nh_gw) { 737 struct fib_result res; 738 739 if (nh->nh_flags & RTNH_F_ONLINK) { 740 unsigned int addr_type; 741 742 if (cfg->fc_scope >= RT_SCOPE_LINK) 743 return -EINVAL; 744 dev = __dev_get_by_index(net, nh->nh_oif); 745 if (!dev) 746 return -ENODEV; 747 if (!(dev->flags & IFF_UP)) 748 return -ENETDOWN; 749 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 750 if (addr_type != RTN_UNICAST) 751 return -EINVAL; 752 if (!netif_carrier_ok(dev)) 753 nh->nh_flags |= RTNH_F_LINKDOWN; 754 nh->nh_dev = dev; 755 dev_hold(dev); 756 nh->nh_scope = RT_SCOPE_LINK; 757 return 0; 758 } 759 rcu_read_lock(); 760 { 761 struct fib_table *tbl = NULL; 762 struct flowi4 fl4 = { 763 .daddr = nh->nh_gw, 764 .flowi4_scope = cfg->fc_scope + 1, 765 .flowi4_oif = nh->nh_oif, 766 .flowi4_iif = LOOPBACK_IFINDEX, 767 }; 768 769 /* It is not necessary, but requires a bit of thinking */ 770 if (fl4.flowi4_scope < RT_SCOPE_LINK) 771 fl4.flowi4_scope = RT_SCOPE_LINK; 772 773 if (cfg->fc_table) 774 tbl = fib_get_table(net, cfg->fc_table); 775 776 if (tbl) 777 err = fib_table_lookup(tbl, &fl4, &res, 778 FIB_LOOKUP_IGNORE_LINKSTATE | 779 FIB_LOOKUP_NOREF); 780 781 /* on error or if no table given do full lookup. This 782 * is needed for example when nexthops are in the local 783 * table rather than the given table 784 */ 785 if (!tbl || err) { 786 err = fib_lookup(net, &fl4, &res, 787 FIB_LOOKUP_IGNORE_LINKSTATE); 788 } 789 790 if (err) { 791 rcu_read_unlock(); 792 return err; 793 } 794 } 795 err = -EINVAL; 796 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 797 goto out; 798 nh->nh_scope = res.scope; 799 nh->nh_oif = FIB_RES_OIF(res); 800 nh->nh_dev = dev = FIB_RES_DEV(res); 801 if (!dev) 802 goto out; 803 dev_hold(dev); 804 if (!netif_carrier_ok(dev)) 805 nh->nh_flags |= RTNH_F_LINKDOWN; 806 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 807 } else { 808 struct in_device *in_dev; 809 810 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 811 return -EINVAL; 812 813 rcu_read_lock(); 814 err = -ENODEV; 815 in_dev = inetdev_by_index(net, nh->nh_oif); 816 if (!in_dev) 817 goto out; 818 err = -ENETDOWN; 819 if (!(in_dev->dev->flags & IFF_UP)) 820 goto out; 821 nh->nh_dev = in_dev->dev; 822 dev_hold(nh->nh_dev); 823 nh->nh_scope = RT_SCOPE_HOST; 824 if (!netif_carrier_ok(nh->nh_dev)) 825 nh->nh_flags |= RTNH_F_LINKDOWN; 826 err = 0; 827 } 828 out: 829 rcu_read_unlock(); 830 return err; 831 } 832 833 static inline unsigned int fib_laddr_hashfn(__be32 val) 834 { 835 unsigned int mask = (fib_info_hash_size - 1); 836 837 return ((__force u32)val ^ 838 ((__force u32)val >> 7) ^ 839 ((__force u32)val >> 14)) & mask; 840 } 841 842 static struct hlist_head *fib_info_hash_alloc(int bytes) 843 { 844 if (bytes <= PAGE_SIZE) 845 return kzalloc(bytes, GFP_KERNEL); 846 else 847 return (struct hlist_head *) 848 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 849 get_order(bytes)); 850 } 851 852 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 853 { 854 if (!hash) 855 return; 856 857 if (bytes <= PAGE_SIZE) 858 kfree(hash); 859 else 860 free_pages((unsigned long) hash, get_order(bytes)); 861 } 862 863 static void fib_info_hash_move(struct hlist_head *new_info_hash, 864 struct hlist_head *new_laddrhash, 865 unsigned int new_size) 866 { 867 struct hlist_head *old_info_hash, *old_laddrhash; 868 unsigned int old_size = fib_info_hash_size; 869 unsigned int i, bytes; 870 871 spin_lock_bh(&fib_info_lock); 872 old_info_hash = fib_info_hash; 873 old_laddrhash = fib_info_laddrhash; 874 fib_info_hash_size = new_size; 875 876 for (i = 0; i < old_size; i++) { 877 struct hlist_head *head = &fib_info_hash[i]; 878 struct hlist_node *n; 879 struct fib_info *fi; 880 881 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 882 struct hlist_head *dest; 883 unsigned int new_hash; 884 885 new_hash = fib_info_hashfn(fi); 886 dest = &new_info_hash[new_hash]; 887 hlist_add_head(&fi->fib_hash, dest); 888 } 889 } 890 fib_info_hash = new_info_hash; 891 892 for (i = 0; i < old_size; i++) { 893 struct hlist_head *lhead = &fib_info_laddrhash[i]; 894 struct hlist_node *n; 895 struct fib_info *fi; 896 897 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 898 struct hlist_head *ldest; 899 unsigned int new_hash; 900 901 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 902 ldest = &new_laddrhash[new_hash]; 903 hlist_add_head(&fi->fib_lhash, ldest); 904 } 905 } 906 fib_info_laddrhash = new_laddrhash; 907 908 spin_unlock_bh(&fib_info_lock); 909 910 bytes = old_size * sizeof(struct hlist_head *); 911 fib_info_hash_free(old_info_hash, bytes); 912 fib_info_hash_free(old_laddrhash, bytes); 913 } 914 915 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 916 { 917 nh->nh_saddr = inet_select_addr(nh->nh_dev, 918 nh->nh_gw, 919 nh->nh_parent->fib_scope); 920 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 921 922 return nh->nh_saddr; 923 } 924 925 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 926 { 927 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 928 fib_prefsrc != cfg->fc_dst) { 929 u32 tb_id = cfg->fc_table; 930 int rc; 931 932 if (tb_id == RT_TABLE_MAIN) 933 tb_id = RT_TABLE_LOCAL; 934 935 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 936 fib_prefsrc, tb_id); 937 938 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 939 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 940 fib_prefsrc, RT_TABLE_LOCAL); 941 } 942 943 if (rc != RTN_LOCAL) 944 return false; 945 } 946 return true; 947 } 948 949 static int 950 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 951 { 952 bool ecn_ca = false; 953 struct nlattr *nla; 954 int remaining; 955 956 if (!cfg->fc_mx) 957 return 0; 958 959 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 960 int type = nla_type(nla); 961 u32 val; 962 963 if (!type) 964 continue; 965 if (type > RTAX_MAX) 966 return -EINVAL; 967 968 if (type == RTAX_CC_ALGO) { 969 char tmp[TCP_CA_NAME_MAX]; 970 971 nla_strlcpy(tmp, nla, sizeof(tmp)); 972 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 973 if (val == TCP_CA_UNSPEC) 974 return -EINVAL; 975 } else { 976 val = nla_get_u32(nla); 977 } 978 if (type == RTAX_ADVMSS && val > 65535 - 40) 979 val = 65535 - 40; 980 if (type == RTAX_MTU && val > 65535 - 15) 981 val = 65535 - 15; 982 if (type == RTAX_HOPLIMIT && val > 255) 983 val = 255; 984 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 985 return -EINVAL; 986 fi->fib_metrics[type - 1] = val; 987 } 988 989 if (ecn_ca) 990 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 991 992 return 0; 993 } 994 995 struct fib_info *fib_create_info(struct fib_config *cfg) 996 { 997 int err; 998 struct fib_info *fi = NULL; 999 struct fib_info *ofi; 1000 int nhs = 1; 1001 struct net *net = cfg->fc_nlinfo.nl_net; 1002 1003 if (cfg->fc_type > RTN_MAX) 1004 goto err_inval; 1005 1006 /* Fast check to catch the most weird cases */ 1007 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 1008 goto err_inval; 1009 1010 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) 1011 goto err_inval; 1012 1013 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1014 if (cfg->fc_mp) { 1015 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 1016 if (nhs == 0) 1017 goto err_inval; 1018 } 1019 #endif 1020 1021 err = -ENOBUFS; 1022 if (fib_info_cnt >= fib_info_hash_size) { 1023 unsigned int new_size = fib_info_hash_size << 1; 1024 struct hlist_head *new_info_hash; 1025 struct hlist_head *new_laddrhash; 1026 unsigned int bytes; 1027 1028 if (!new_size) 1029 new_size = 16; 1030 bytes = new_size * sizeof(struct hlist_head *); 1031 new_info_hash = fib_info_hash_alloc(bytes); 1032 new_laddrhash = fib_info_hash_alloc(bytes); 1033 if (!new_info_hash || !new_laddrhash) { 1034 fib_info_hash_free(new_info_hash, bytes); 1035 fib_info_hash_free(new_laddrhash, bytes); 1036 } else 1037 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1038 1039 if (!fib_info_hash_size) 1040 goto failure; 1041 } 1042 1043 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1044 if (!fi) 1045 goto failure; 1046 fib_info_cnt++; 1047 if (cfg->fc_mx) { 1048 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 1049 if (!fi->fib_metrics) 1050 goto failure; 1051 } else 1052 fi->fib_metrics = (u32 *) dst_default_metrics; 1053 1054 fi->fib_net = net; 1055 fi->fib_protocol = cfg->fc_protocol; 1056 fi->fib_scope = cfg->fc_scope; 1057 fi->fib_flags = cfg->fc_flags; 1058 fi->fib_priority = cfg->fc_priority; 1059 fi->fib_prefsrc = cfg->fc_prefsrc; 1060 fi->fib_type = cfg->fc_type; 1061 fi->fib_tb_id = cfg->fc_table; 1062 1063 fi->fib_nhs = nhs; 1064 change_nexthops(fi) { 1065 nexthop_nh->nh_parent = fi; 1066 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1067 if (!nexthop_nh->nh_pcpu_rth_output) 1068 goto failure; 1069 } endfor_nexthops(fi) 1070 1071 err = fib_convert_metrics(fi, cfg); 1072 if (err) 1073 goto failure; 1074 1075 if (cfg->fc_mp) { 1076 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1077 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 1078 if (err != 0) 1079 goto failure; 1080 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 1081 goto err_inval; 1082 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 1083 goto err_inval; 1084 #ifdef CONFIG_IP_ROUTE_CLASSID 1085 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 1086 goto err_inval; 1087 #endif 1088 #else 1089 goto err_inval; 1090 #endif 1091 } else { 1092 struct fib_nh *nh = fi->fib_nh; 1093 1094 if (cfg->fc_encap) { 1095 struct lwtunnel_state *lwtstate; 1096 struct net_device *dev = NULL; 1097 1098 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) 1099 goto err_inval; 1100 if (cfg->fc_oif) 1101 dev = __dev_get_by_index(net, cfg->fc_oif); 1102 err = lwtunnel_build_state(dev, cfg->fc_encap_type, 1103 cfg->fc_encap, AF_INET, cfg, 1104 &lwtstate); 1105 if (err) 1106 goto failure; 1107 1108 nh->nh_lwtstate = lwtstate_get(lwtstate); 1109 } 1110 nh->nh_oif = cfg->fc_oif; 1111 nh->nh_gw = cfg->fc_gw; 1112 nh->nh_flags = cfg->fc_flags; 1113 #ifdef CONFIG_IP_ROUTE_CLASSID 1114 nh->nh_tclassid = cfg->fc_flow; 1115 if (nh->nh_tclassid) 1116 fi->fib_net->ipv4.fib_num_tclassid_users++; 1117 #endif 1118 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1119 nh->nh_weight = 1; 1120 #endif 1121 } 1122 1123 if (fib_props[cfg->fc_type].error) { 1124 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 1125 goto err_inval; 1126 goto link_it; 1127 } else { 1128 switch (cfg->fc_type) { 1129 case RTN_UNICAST: 1130 case RTN_LOCAL: 1131 case RTN_BROADCAST: 1132 case RTN_ANYCAST: 1133 case RTN_MULTICAST: 1134 break; 1135 default: 1136 goto err_inval; 1137 } 1138 } 1139 1140 if (cfg->fc_scope > RT_SCOPE_HOST) 1141 goto err_inval; 1142 1143 if (cfg->fc_scope == RT_SCOPE_HOST) { 1144 struct fib_nh *nh = fi->fib_nh; 1145 1146 /* Local address is added. */ 1147 if (nhs != 1 || nh->nh_gw) 1148 goto err_inval; 1149 nh->nh_scope = RT_SCOPE_NOWHERE; 1150 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1151 err = -ENODEV; 1152 if (!nh->nh_dev) 1153 goto failure; 1154 } else { 1155 int linkdown = 0; 1156 1157 change_nexthops(fi) { 1158 err = fib_check_nh(cfg, fi, nexthop_nh); 1159 if (err != 0) 1160 goto failure; 1161 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1162 linkdown++; 1163 } endfor_nexthops(fi) 1164 if (linkdown == fi->fib_nhs) 1165 fi->fib_flags |= RTNH_F_LINKDOWN; 1166 } 1167 1168 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) 1169 goto err_inval; 1170 1171 change_nexthops(fi) { 1172 fib_info_update_nh_saddr(net, nexthop_nh); 1173 fib_add_weight(fi, nexthop_nh); 1174 } endfor_nexthops(fi) 1175 1176 fib_rebalance(fi); 1177 1178 link_it: 1179 ofi = fib_find_info(fi); 1180 if (ofi) { 1181 fi->fib_dead = 1; 1182 free_fib_info(fi); 1183 ofi->fib_treeref++; 1184 return ofi; 1185 } 1186 1187 fi->fib_treeref++; 1188 atomic_inc(&fi->fib_clntref); 1189 spin_lock_bh(&fib_info_lock); 1190 hlist_add_head(&fi->fib_hash, 1191 &fib_info_hash[fib_info_hashfn(fi)]); 1192 if (fi->fib_prefsrc) { 1193 struct hlist_head *head; 1194 1195 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1196 hlist_add_head(&fi->fib_lhash, head); 1197 } 1198 change_nexthops(fi) { 1199 struct hlist_head *head; 1200 unsigned int hash; 1201 1202 if (!nexthop_nh->nh_dev) 1203 continue; 1204 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1205 head = &fib_info_devhash[hash]; 1206 hlist_add_head(&nexthop_nh->nh_hash, head); 1207 } endfor_nexthops(fi) 1208 spin_unlock_bh(&fib_info_lock); 1209 return fi; 1210 1211 err_inval: 1212 err = -EINVAL; 1213 1214 failure: 1215 if (fi) { 1216 fi->fib_dead = 1; 1217 free_fib_info(fi); 1218 } 1219 1220 return ERR_PTR(err); 1221 } 1222 1223 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1224 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1225 struct fib_info *fi, unsigned int flags) 1226 { 1227 struct nlmsghdr *nlh; 1228 struct rtmsg *rtm; 1229 1230 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1231 if (!nlh) 1232 return -EMSGSIZE; 1233 1234 rtm = nlmsg_data(nlh); 1235 rtm->rtm_family = AF_INET; 1236 rtm->rtm_dst_len = dst_len; 1237 rtm->rtm_src_len = 0; 1238 rtm->rtm_tos = tos; 1239 if (tb_id < 256) 1240 rtm->rtm_table = tb_id; 1241 else 1242 rtm->rtm_table = RT_TABLE_COMPAT; 1243 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1244 goto nla_put_failure; 1245 rtm->rtm_type = type; 1246 rtm->rtm_flags = fi->fib_flags; 1247 rtm->rtm_scope = fi->fib_scope; 1248 rtm->rtm_protocol = fi->fib_protocol; 1249 1250 if (rtm->rtm_dst_len && 1251 nla_put_in_addr(skb, RTA_DST, dst)) 1252 goto nla_put_failure; 1253 if (fi->fib_priority && 1254 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1255 goto nla_put_failure; 1256 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1257 goto nla_put_failure; 1258 1259 if (fi->fib_prefsrc && 1260 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1261 goto nla_put_failure; 1262 if (fi->fib_nhs == 1) { 1263 struct in_device *in_dev; 1264 1265 if (fi->fib_nh->nh_gw && 1266 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1267 goto nla_put_failure; 1268 if (fi->fib_nh->nh_oif && 1269 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1270 goto nla_put_failure; 1271 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1272 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1273 if (in_dev && 1274 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1275 rtm->rtm_flags |= RTNH_F_DEAD; 1276 } 1277 #ifdef CONFIG_IP_ROUTE_CLASSID 1278 if (fi->fib_nh[0].nh_tclassid && 1279 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1280 goto nla_put_failure; 1281 #endif 1282 if (fi->fib_nh->nh_lwtstate) 1283 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate); 1284 } 1285 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1286 if (fi->fib_nhs > 1) { 1287 struct rtnexthop *rtnh; 1288 struct nlattr *mp; 1289 1290 mp = nla_nest_start(skb, RTA_MULTIPATH); 1291 if (!mp) 1292 goto nla_put_failure; 1293 1294 for_nexthops(fi) { 1295 struct in_device *in_dev; 1296 1297 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1298 if (!rtnh) 1299 goto nla_put_failure; 1300 1301 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1302 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1303 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1304 if (in_dev && 1305 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1306 rtnh->rtnh_flags |= RTNH_F_DEAD; 1307 } 1308 rtnh->rtnh_hops = nh->nh_weight - 1; 1309 rtnh->rtnh_ifindex = nh->nh_oif; 1310 1311 if (nh->nh_gw && 1312 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1313 goto nla_put_failure; 1314 #ifdef CONFIG_IP_ROUTE_CLASSID 1315 if (nh->nh_tclassid && 1316 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1317 goto nla_put_failure; 1318 #endif 1319 if (nh->nh_lwtstate) 1320 lwtunnel_fill_encap(skb, nh->nh_lwtstate); 1321 /* length of rtnetlink header + attributes */ 1322 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1323 } endfor_nexthops(fi); 1324 1325 nla_nest_end(skb, mp); 1326 } 1327 #endif 1328 nlmsg_end(skb, nlh); 1329 return 0; 1330 1331 nla_put_failure: 1332 nlmsg_cancel(skb, nlh); 1333 return -EMSGSIZE; 1334 } 1335 1336 /* 1337 * Update FIB if: 1338 * - local address disappeared -> we must delete all the entries 1339 * referring to it. 1340 * - device went down -> we must shutdown all nexthops going via it. 1341 */ 1342 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1343 { 1344 int ret = 0; 1345 unsigned int hash = fib_laddr_hashfn(local); 1346 struct hlist_head *head = &fib_info_laddrhash[hash]; 1347 struct net *net = dev_net(dev); 1348 int tb_id = l3mdev_fib_table(dev); 1349 struct fib_info *fi; 1350 1351 if (!fib_info_laddrhash || local == 0) 1352 return 0; 1353 1354 hlist_for_each_entry(fi, head, fib_lhash) { 1355 if (!net_eq(fi->fib_net, net) || 1356 fi->fib_tb_id != tb_id) 1357 continue; 1358 if (fi->fib_prefsrc == local) { 1359 fi->fib_flags |= RTNH_F_DEAD; 1360 ret++; 1361 } 1362 } 1363 return ret; 1364 } 1365 1366 /* Event force Flags Description 1367 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1368 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1369 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1370 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1371 */ 1372 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1373 { 1374 int ret = 0; 1375 int scope = RT_SCOPE_NOWHERE; 1376 struct fib_info *prev_fi = NULL; 1377 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1378 struct hlist_head *head = &fib_info_devhash[hash]; 1379 struct fib_nh *nh; 1380 1381 if (force) 1382 scope = -1; 1383 1384 hlist_for_each_entry(nh, head, nh_hash) { 1385 struct fib_info *fi = nh->nh_parent; 1386 int dead; 1387 1388 BUG_ON(!fi->fib_nhs); 1389 if (nh->nh_dev != dev || fi == prev_fi) 1390 continue; 1391 prev_fi = fi; 1392 dead = 0; 1393 change_nexthops(fi) { 1394 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1395 dead++; 1396 else if (nexthop_nh->nh_dev == dev && 1397 nexthop_nh->nh_scope != scope) { 1398 switch (event) { 1399 case NETDEV_DOWN: 1400 case NETDEV_UNREGISTER: 1401 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1402 /* fall through */ 1403 case NETDEV_CHANGE: 1404 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1405 break; 1406 } 1407 dead++; 1408 } 1409 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1410 if (event == NETDEV_UNREGISTER && 1411 nexthop_nh->nh_dev == dev) { 1412 dead = fi->fib_nhs; 1413 break; 1414 } 1415 #endif 1416 } endfor_nexthops(fi) 1417 if (dead == fi->fib_nhs) { 1418 switch (event) { 1419 case NETDEV_DOWN: 1420 case NETDEV_UNREGISTER: 1421 fi->fib_flags |= RTNH_F_DEAD; 1422 /* fall through */ 1423 case NETDEV_CHANGE: 1424 fi->fib_flags |= RTNH_F_LINKDOWN; 1425 break; 1426 } 1427 ret++; 1428 } 1429 1430 fib_rebalance(fi); 1431 } 1432 1433 return ret; 1434 } 1435 1436 /* Must be invoked inside of an RCU protected region. */ 1437 void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1438 { 1439 struct fib_info *fi = NULL, *last_resort = NULL; 1440 struct hlist_head *fa_head = res->fa_head; 1441 struct fib_table *tb = res->table; 1442 u8 slen = 32 - res->prefixlen; 1443 int order = -1, last_idx = -1; 1444 struct fib_alias *fa, *fa1 = NULL; 1445 u32 last_prio = res->fi->fib_priority; 1446 u8 last_tos = 0; 1447 1448 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1449 struct fib_info *next_fi = fa->fa_info; 1450 1451 if (fa->fa_slen != slen) 1452 continue; 1453 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1454 continue; 1455 if (fa->tb_id != tb->tb_id) 1456 continue; 1457 if (next_fi->fib_priority > last_prio && 1458 fa->fa_tos == last_tos) { 1459 if (last_tos) 1460 continue; 1461 break; 1462 } 1463 if (next_fi->fib_flags & RTNH_F_DEAD) 1464 continue; 1465 last_tos = fa->fa_tos; 1466 last_prio = next_fi->fib_priority; 1467 1468 if (next_fi->fib_scope != res->scope || 1469 fa->fa_type != RTN_UNICAST) 1470 continue; 1471 if (!next_fi->fib_nh[0].nh_gw || 1472 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1473 continue; 1474 1475 fib_alias_accessed(fa); 1476 1477 if (!fi) { 1478 if (next_fi != res->fi) 1479 break; 1480 fa1 = fa; 1481 } else if (!fib_detect_death(fi, order, &last_resort, 1482 &last_idx, fa1->fa_default)) { 1483 fib_result_assign(res, fi); 1484 fa1->fa_default = order; 1485 goto out; 1486 } 1487 fi = next_fi; 1488 order++; 1489 } 1490 1491 if (order <= 0 || !fi) { 1492 if (fa1) 1493 fa1->fa_default = -1; 1494 goto out; 1495 } 1496 1497 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1498 fa1->fa_default)) { 1499 fib_result_assign(res, fi); 1500 fa1->fa_default = order; 1501 goto out; 1502 } 1503 1504 if (last_idx >= 0) 1505 fib_result_assign(res, last_resort); 1506 fa1->fa_default = last_idx; 1507 out: 1508 return; 1509 } 1510 1511 /* 1512 * Dead device goes up. We wake up dead nexthops. 1513 * It takes sense only on multipath routes. 1514 */ 1515 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1516 { 1517 struct fib_info *prev_fi; 1518 unsigned int hash; 1519 struct hlist_head *head; 1520 struct fib_nh *nh; 1521 int ret; 1522 1523 if (!(dev->flags & IFF_UP)) 1524 return 0; 1525 1526 if (nh_flags & RTNH_F_DEAD) { 1527 unsigned int flags = dev_get_flags(dev); 1528 1529 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1530 nh_flags |= RTNH_F_LINKDOWN; 1531 } 1532 1533 prev_fi = NULL; 1534 hash = fib_devindex_hashfn(dev->ifindex); 1535 head = &fib_info_devhash[hash]; 1536 ret = 0; 1537 1538 hlist_for_each_entry(nh, head, nh_hash) { 1539 struct fib_info *fi = nh->nh_parent; 1540 int alive; 1541 1542 BUG_ON(!fi->fib_nhs); 1543 if (nh->nh_dev != dev || fi == prev_fi) 1544 continue; 1545 1546 prev_fi = fi; 1547 alive = 0; 1548 change_nexthops(fi) { 1549 if (!(nexthop_nh->nh_flags & nh_flags)) { 1550 alive++; 1551 continue; 1552 } 1553 if (!nexthop_nh->nh_dev || 1554 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1555 continue; 1556 if (nexthop_nh->nh_dev != dev || 1557 !__in_dev_get_rtnl(dev)) 1558 continue; 1559 alive++; 1560 nexthop_nh->nh_flags &= ~nh_flags; 1561 } endfor_nexthops(fi) 1562 1563 if (alive > 0) { 1564 fi->fib_flags &= ~nh_flags; 1565 ret++; 1566 } 1567 1568 fib_rebalance(fi); 1569 } 1570 1571 return ret; 1572 } 1573 1574 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1575 static bool fib_good_nh(const struct fib_nh *nh) 1576 { 1577 int state = NUD_REACHABLE; 1578 1579 if (nh->nh_scope == RT_SCOPE_LINK) { 1580 struct neighbour *n; 1581 1582 rcu_read_lock_bh(); 1583 1584 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1585 (__force u32)nh->nh_gw); 1586 if (n) 1587 state = n->nud_state; 1588 1589 rcu_read_unlock_bh(); 1590 } 1591 1592 return !!(state & NUD_VALID); 1593 } 1594 1595 void fib_select_multipath(struct fib_result *res, int hash) 1596 { 1597 struct fib_info *fi = res->fi; 1598 struct net *net = fi->fib_net; 1599 bool first = false; 1600 1601 for_nexthops(fi) { 1602 if (hash > atomic_read(&nh->nh_upper_bound)) 1603 continue; 1604 1605 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1606 fib_good_nh(nh)) { 1607 res->nh_sel = nhsel; 1608 return; 1609 } 1610 if (!first) { 1611 res->nh_sel = nhsel; 1612 first = true; 1613 } 1614 } endfor_nexthops(fi); 1615 } 1616 #endif 1617 1618 void fib_select_path(struct net *net, struct fib_result *res, 1619 struct flowi4 *fl4, int mp_hash) 1620 { 1621 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1622 if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) { 1623 if (mp_hash < 0) 1624 mp_hash = get_hash_from_flowi4(fl4) >> 1; 1625 1626 fib_select_multipath(res, mp_hash); 1627 } 1628 else 1629 #endif 1630 if (!res->prefixlen && 1631 res->table->tb_num_default > 1 && 1632 res->type == RTN_UNICAST && !fl4->flowi4_oif) 1633 fib_select_default(fl4, res); 1634 1635 if (!fl4->saddr) 1636 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1637 } 1638 EXPORT_SYMBOL_GPL(fib_select_path); 1639