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 #include <linux/netlink.h> 36 37 #include <net/arp.h> 38 #include <net/ip.h> 39 #include <net/protocol.h> 40 #include <net/route.h> 41 #include <net/tcp.h> 42 #include <net/sock.h> 43 #include <net/ip_fib.h> 44 #include <net/netlink.h> 45 #include <net/nexthop.h> 46 #include <net/lwtunnel.h> 47 #include <net/fib_notifier.h> 48 49 #include "fib_lookup.h" 50 51 static DEFINE_SPINLOCK(fib_info_lock); 52 static struct hlist_head *fib_info_hash; 53 static struct hlist_head *fib_info_laddrhash; 54 static unsigned int fib_info_hash_size; 55 static unsigned int fib_info_cnt; 56 57 #define DEVINDEX_HASHBITS 8 58 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 59 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 60 61 #ifdef CONFIG_IP_ROUTE_MULTIPATH 62 63 #define for_nexthops(fi) { \ 64 int nhsel; const struct fib_nh *nh; \ 65 for (nhsel = 0, nh = (fi)->fib_nh; \ 66 nhsel < (fi)->fib_nhs; \ 67 nh++, nhsel++) 68 69 #define change_nexthops(fi) { \ 70 int nhsel; struct fib_nh *nexthop_nh; \ 71 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 72 nhsel < (fi)->fib_nhs; \ 73 nexthop_nh++, nhsel++) 74 75 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 76 77 /* Hope, that gcc will optimize it to get rid of dummy loop */ 78 79 #define for_nexthops(fi) { \ 80 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 81 for (nhsel = 0; nhsel < 1; nhsel++) 82 83 #define change_nexthops(fi) { \ 84 int nhsel; \ 85 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 86 for (nhsel = 0; nhsel < 1; nhsel++) 87 88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 89 90 #define endfor_nexthops(fi) } 91 92 93 const struct fib_prop fib_props[RTN_MAX + 1] = { 94 [RTN_UNSPEC] = { 95 .error = 0, 96 .scope = RT_SCOPE_NOWHERE, 97 }, 98 [RTN_UNICAST] = { 99 .error = 0, 100 .scope = RT_SCOPE_UNIVERSE, 101 }, 102 [RTN_LOCAL] = { 103 .error = 0, 104 .scope = RT_SCOPE_HOST, 105 }, 106 [RTN_BROADCAST] = { 107 .error = 0, 108 .scope = RT_SCOPE_LINK, 109 }, 110 [RTN_ANYCAST] = { 111 .error = 0, 112 .scope = RT_SCOPE_LINK, 113 }, 114 [RTN_MULTICAST] = { 115 .error = 0, 116 .scope = RT_SCOPE_UNIVERSE, 117 }, 118 [RTN_BLACKHOLE] = { 119 .error = -EINVAL, 120 .scope = RT_SCOPE_UNIVERSE, 121 }, 122 [RTN_UNREACHABLE] = { 123 .error = -EHOSTUNREACH, 124 .scope = RT_SCOPE_UNIVERSE, 125 }, 126 [RTN_PROHIBIT] = { 127 .error = -EACCES, 128 .scope = RT_SCOPE_UNIVERSE, 129 }, 130 [RTN_THROW] = { 131 .error = -EAGAIN, 132 .scope = RT_SCOPE_UNIVERSE, 133 }, 134 [RTN_NAT] = { 135 .error = -EINVAL, 136 .scope = RT_SCOPE_NOWHERE, 137 }, 138 [RTN_XRESOLVE] = { 139 .error = -EINVAL, 140 .scope = RT_SCOPE_NOWHERE, 141 }, 142 }; 143 144 static void rt_fibinfo_free(struct rtable __rcu **rtp) 145 { 146 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 147 148 if (!rt) 149 return; 150 151 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 152 * because we waited an RCU grace period before calling 153 * free_fib_info_rcu() 154 */ 155 156 dst_dev_put(&rt->dst); 157 dst_release_immediate(&rt->dst); 158 } 159 160 static void free_nh_exceptions(struct fib_nh *nh) 161 { 162 struct fnhe_hash_bucket *hash; 163 int i; 164 165 hash = rcu_dereference_protected(nh->nh_exceptions, 1); 166 if (!hash) 167 return; 168 for (i = 0; i < FNHE_HASH_SIZE; i++) { 169 struct fib_nh_exception *fnhe; 170 171 fnhe = rcu_dereference_protected(hash[i].chain, 1); 172 while (fnhe) { 173 struct fib_nh_exception *next; 174 175 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 176 177 rt_fibinfo_free(&fnhe->fnhe_rth_input); 178 rt_fibinfo_free(&fnhe->fnhe_rth_output); 179 180 kfree(fnhe); 181 182 fnhe = next; 183 } 184 } 185 kfree(hash); 186 } 187 188 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 189 { 190 int cpu; 191 192 if (!rtp) 193 return; 194 195 for_each_possible_cpu(cpu) { 196 struct rtable *rt; 197 198 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 199 if (rt) { 200 dst_dev_put(&rt->dst); 201 dst_release_immediate(&rt->dst); 202 } 203 } 204 free_percpu(rtp); 205 } 206 207 /* Release a nexthop info record */ 208 static void free_fib_info_rcu(struct rcu_head *head) 209 { 210 struct fib_info *fi = container_of(head, struct fib_info, rcu); 211 212 change_nexthops(fi) { 213 if (nexthop_nh->nh_dev) 214 dev_put(nexthop_nh->nh_dev); 215 lwtstate_put(nexthop_nh->nh_lwtstate); 216 free_nh_exceptions(nexthop_nh); 217 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 218 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 219 } endfor_nexthops(fi); 220 221 ip_fib_metrics_put(fi->fib_metrics); 222 223 kfree(fi); 224 } 225 226 void free_fib_info(struct fib_info *fi) 227 { 228 if (fi->fib_dead == 0) { 229 pr_warn("Freeing alive fib_info %p\n", fi); 230 return; 231 } 232 fib_info_cnt--; 233 #ifdef CONFIG_IP_ROUTE_CLASSID 234 change_nexthops(fi) { 235 if (nexthop_nh->nh_tclassid) 236 fi->fib_net->ipv4.fib_num_tclassid_users--; 237 } endfor_nexthops(fi); 238 #endif 239 call_rcu(&fi->rcu, free_fib_info_rcu); 240 } 241 EXPORT_SYMBOL_GPL(free_fib_info); 242 243 void fib_release_info(struct fib_info *fi) 244 { 245 spin_lock_bh(&fib_info_lock); 246 if (fi && --fi->fib_treeref == 0) { 247 hlist_del(&fi->fib_hash); 248 if (fi->fib_prefsrc) 249 hlist_del(&fi->fib_lhash); 250 change_nexthops(fi) { 251 if (!nexthop_nh->nh_dev) 252 continue; 253 hlist_del(&nexthop_nh->nh_hash); 254 } endfor_nexthops(fi) 255 fi->fib_dead = 1; 256 fib_info_put(fi); 257 } 258 spin_unlock_bh(&fib_info_lock); 259 } 260 261 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 262 { 263 const struct fib_nh *onh = ofi->fib_nh; 264 265 for_nexthops(fi) { 266 if (nh->nh_oif != onh->nh_oif || 267 nh->nh_gw != onh->nh_gw || 268 nh->nh_scope != onh->nh_scope || 269 #ifdef CONFIG_IP_ROUTE_MULTIPATH 270 nh->nh_weight != onh->nh_weight || 271 #endif 272 #ifdef CONFIG_IP_ROUTE_CLASSID 273 nh->nh_tclassid != onh->nh_tclassid || 274 #endif 275 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) || 276 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK)) 277 return -1; 278 onh++; 279 } endfor_nexthops(fi); 280 return 0; 281 } 282 283 static inline unsigned int fib_devindex_hashfn(unsigned int val) 284 { 285 unsigned int mask = DEVINDEX_HASHSIZE - 1; 286 287 return (val ^ 288 (val >> DEVINDEX_HASHBITS) ^ 289 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 290 } 291 292 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 293 { 294 unsigned int mask = (fib_info_hash_size - 1); 295 unsigned int val = fi->fib_nhs; 296 297 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 298 val ^= (__force u32)fi->fib_prefsrc; 299 val ^= fi->fib_priority; 300 for_nexthops(fi) { 301 val ^= fib_devindex_hashfn(nh->nh_oif); 302 } endfor_nexthops(fi) 303 304 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 305 } 306 307 static struct fib_info *fib_find_info(const struct fib_info *nfi) 308 { 309 struct hlist_head *head; 310 struct fib_info *fi; 311 unsigned int hash; 312 313 hash = fib_info_hashfn(nfi); 314 head = &fib_info_hash[hash]; 315 316 hlist_for_each_entry(fi, head, fib_hash) { 317 if (!net_eq(fi->fib_net, nfi->fib_net)) 318 continue; 319 if (fi->fib_nhs != nfi->fib_nhs) 320 continue; 321 if (nfi->fib_protocol == fi->fib_protocol && 322 nfi->fib_scope == fi->fib_scope && 323 nfi->fib_prefsrc == fi->fib_prefsrc && 324 nfi->fib_priority == fi->fib_priority && 325 nfi->fib_type == fi->fib_type && 326 memcmp(nfi->fib_metrics, fi->fib_metrics, 327 sizeof(u32) * RTAX_MAX) == 0 && 328 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 329 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 330 return fi; 331 } 332 333 return NULL; 334 } 335 336 /* Check, that the gateway is already configured. 337 * Used only by redirect accept routine. 338 */ 339 int ip_fib_check_default(__be32 gw, struct net_device *dev) 340 { 341 struct hlist_head *head; 342 struct fib_nh *nh; 343 unsigned int hash; 344 345 spin_lock(&fib_info_lock); 346 347 hash = fib_devindex_hashfn(dev->ifindex); 348 head = &fib_info_devhash[hash]; 349 hlist_for_each_entry(nh, head, nh_hash) { 350 if (nh->nh_dev == dev && 351 nh->nh_gw == gw && 352 !(nh->nh_flags & RTNH_F_DEAD)) { 353 spin_unlock(&fib_info_lock); 354 return 0; 355 } 356 } 357 358 spin_unlock(&fib_info_lock); 359 360 return -1; 361 } 362 363 static inline size_t fib_nlmsg_size(struct fib_info *fi) 364 { 365 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 366 + nla_total_size(4) /* RTA_TABLE */ 367 + nla_total_size(4) /* RTA_DST */ 368 + nla_total_size(4) /* RTA_PRIORITY */ 369 + nla_total_size(4) /* RTA_PREFSRC */ 370 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 371 372 /* space for nested metrics */ 373 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 374 375 if (fi->fib_nhs) { 376 size_t nh_encapsize = 0; 377 /* Also handles the special case fib_nhs == 1 */ 378 379 /* each nexthop is packed in an attribute */ 380 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 381 382 /* may contain flow and gateway attribute */ 383 nhsize += 2 * nla_total_size(4); 384 385 /* grab encap info */ 386 for_nexthops(fi) { 387 if (nh->nh_lwtstate) { 388 /* RTA_ENCAP_TYPE */ 389 nh_encapsize += lwtunnel_get_encap_size( 390 nh->nh_lwtstate); 391 /* RTA_ENCAP */ 392 nh_encapsize += nla_total_size(2); 393 } 394 } endfor_nexthops(fi); 395 396 /* all nexthops are packed in a nested attribute */ 397 payload += nla_total_size((fi->fib_nhs * nhsize) + 398 nh_encapsize); 399 400 } 401 402 return payload; 403 } 404 405 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 406 int dst_len, u32 tb_id, const struct nl_info *info, 407 unsigned int nlm_flags) 408 { 409 struct sk_buff *skb; 410 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 411 int err = -ENOBUFS; 412 413 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 414 if (!skb) 415 goto errout; 416 417 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 418 fa->fa_type, key, dst_len, 419 fa->fa_tos, fa->fa_info, nlm_flags); 420 if (err < 0) { 421 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 422 WARN_ON(err == -EMSGSIZE); 423 kfree_skb(skb); 424 goto errout; 425 } 426 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 427 info->nlh, GFP_KERNEL); 428 return; 429 errout: 430 if (err < 0) 431 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 432 } 433 434 static int fib_detect_death(struct fib_info *fi, int order, 435 struct fib_info **last_resort, int *last_idx, 436 int dflt) 437 { 438 struct neighbour *n; 439 int state = NUD_NONE; 440 441 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); 442 if (n) { 443 state = n->nud_state; 444 neigh_release(n); 445 } else { 446 return 0; 447 } 448 if (state == NUD_REACHABLE) 449 return 0; 450 if ((state & NUD_VALID) && order != dflt) 451 return 0; 452 if ((state & NUD_VALID) || 453 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 454 *last_resort = fi; 455 *last_idx = order; 456 } 457 return 1; 458 } 459 460 #ifdef CONFIG_IP_ROUTE_MULTIPATH 461 462 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 463 struct netlink_ext_ack *extack) 464 { 465 int nhs = 0; 466 467 while (rtnh_ok(rtnh, remaining)) { 468 nhs++; 469 rtnh = rtnh_next(rtnh, &remaining); 470 } 471 472 /* leftover implies invalid nexthop configuration, discard it */ 473 if (remaining > 0) { 474 NL_SET_ERR_MSG(extack, 475 "Invalid nexthop configuration - extra data after nexthops"); 476 nhs = 0; 477 } 478 479 return nhs; 480 } 481 482 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 483 int remaining, struct fib_config *cfg, 484 struct netlink_ext_ack *extack) 485 { 486 int ret; 487 488 change_nexthops(fi) { 489 int attrlen; 490 491 if (!rtnh_ok(rtnh, remaining)) { 492 NL_SET_ERR_MSG(extack, 493 "Invalid nexthop configuration - extra data after nexthop"); 494 return -EINVAL; 495 } 496 497 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 498 NL_SET_ERR_MSG(extack, 499 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 500 return -EINVAL; 501 } 502 503 nexthop_nh->nh_flags = 504 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 505 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 506 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 507 508 attrlen = rtnh_attrlen(rtnh); 509 if (attrlen > 0) { 510 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 511 512 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 513 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 514 #ifdef CONFIG_IP_ROUTE_CLASSID 515 nla = nla_find(attrs, attrlen, RTA_FLOW); 516 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 517 if (nexthop_nh->nh_tclassid) 518 fi->fib_net->ipv4.fib_num_tclassid_users++; 519 #endif 520 nla = nla_find(attrs, attrlen, RTA_ENCAP); 521 if (nla) { 522 struct lwtunnel_state *lwtstate; 523 struct nlattr *nla_entype; 524 525 nla_entype = nla_find(attrs, attrlen, 526 RTA_ENCAP_TYPE); 527 if (!nla_entype) { 528 NL_SET_BAD_ATTR(extack, nla); 529 NL_SET_ERR_MSG(extack, 530 "Encap type is missing"); 531 goto err_inval; 532 } 533 534 ret = lwtunnel_build_state(nla_get_u16( 535 nla_entype), 536 nla, AF_INET, cfg, 537 &lwtstate, extack); 538 if (ret) 539 goto errout; 540 nexthop_nh->nh_lwtstate = 541 lwtstate_get(lwtstate); 542 } 543 } 544 545 rtnh = rtnh_next(rtnh, &remaining); 546 } endfor_nexthops(fi); 547 548 return 0; 549 550 err_inval: 551 ret = -EINVAL; 552 553 errout: 554 return ret; 555 } 556 557 static void fib_rebalance(struct fib_info *fi) 558 { 559 int total; 560 int w; 561 struct in_device *in_dev; 562 563 if (fi->fib_nhs < 2) 564 return; 565 566 total = 0; 567 for_nexthops(fi) { 568 if (nh->nh_flags & RTNH_F_DEAD) 569 continue; 570 571 in_dev = __in_dev_get_rtnl(nh->nh_dev); 572 573 if (in_dev && 574 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 575 nh->nh_flags & RTNH_F_LINKDOWN) 576 continue; 577 578 total += nh->nh_weight; 579 } endfor_nexthops(fi); 580 581 w = 0; 582 change_nexthops(fi) { 583 int upper_bound; 584 585 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev); 586 587 if (nexthop_nh->nh_flags & RTNH_F_DEAD) { 588 upper_bound = -1; 589 } else if (in_dev && 590 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 591 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) { 592 upper_bound = -1; 593 } else { 594 w += nexthop_nh->nh_weight; 595 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 596 total) - 1; 597 } 598 599 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound); 600 } endfor_nexthops(fi); 601 } 602 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 603 604 #define fib_rebalance(fi) do { } while (0) 605 606 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 607 608 static int fib_encap_match(u16 encap_type, 609 struct nlattr *encap, 610 const struct fib_nh *nh, 611 const struct fib_config *cfg, 612 struct netlink_ext_ack *extack) 613 { 614 struct lwtunnel_state *lwtstate; 615 int ret, result = 0; 616 617 if (encap_type == LWTUNNEL_ENCAP_NONE) 618 return 0; 619 620 ret = lwtunnel_build_state(encap_type, encap, AF_INET, 621 cfg, &lwtstate, extack); 622 if (!ret) { 623 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 624 lwtstate_free(lwtstate); 625 } 626 627 return result; 628 } 629 630 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, 631 struct netlink_ext_ack *extack) 632 { 633 #ifdef CONFIG_IP_ROUTE_MULTIPATH 634 struct rtnexthop *rtnh; 635 int remaining; 636 #endif 637 638 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 639 return 1; 640 641 if (cfg->fc_oif || cfg->fc_gw) { 642 if (cfg->fc_encap) { 643 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap, 644 fi->fib_nh, cfg, extack)) 645 return 1; 646 } 647 #ifdef CONFIG_IP_ROUTE_CLASSID 648 if (cfg->fc_flow && 649 cfg->fc_flow != fi->fib_nh->nh_tclassid) 650 return 1; 651 #endif 652 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 653 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 654 return 0; 655 return 1; 656 } 657 658 #ifdef CONFIG_IP_ROUTE_MULTIPATH 659 if (!cfg->fc_mp) 660 return 0; 661 662 rtnh = cfg->fc_mp; 663 remaining = cfg->fc_mp_len; 664 665 for_nexthops(fi) { 666 int attrlen; 667 668 if (!rtnh_ok(rtnh, remaining)) 669 return -EINVAL; 670 671 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 672 return 1; 673 674 attrlen = rtnh_attrlen(rtnh); 675 if (attrlen > 0) { 676 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 677 678 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 679 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 680 return 1; 681 #ifdef CONFIG_IP_ROUTE_CLASSID 682 nla = nla_find(attrs, attrlen, RTA_FLOW); 683 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 684 return 1; 685 #endif 686 } 687 688 rtnh = rtnh_next(rtnh, &remaining); 689 } endfor_nexthops(fi); 690 #endif 691 return 0; 692 } 693 694 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 695 { 696 struct nlattr *nla; 697 int remaining; 698 699 if (!cfg->fc_mx) 700 return true; 701 702 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 703 int type = nla_type(nla); 704 u32 fi_val, val; 705 706 if (!type) 707 continue; 708 if (type > RTAX_MAX) 709 return false; 710 711 if (type == RTAX_CC_ALGO) { 712 char tmp[TCP_CA_NAME_MAX]; 713 bool ecn_ca = false; 714 715 nla_strlcpy(tmp, nla, sizeof(tmp)); 716 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 717 } else { 718 if (nla_len(nla) != sizeof(u32)) 719 return false; 720 val = nla_get_u32(nla); 721 } 722 723 fi_val = fi->fib_metrics->metrics[type - 1]; 724 if (type == RTAX_FEATURES) 725 fi_val &= ~DST_FEATURE_ECN_CA; 726 727 if (fi_val != val) 728 return false; 729 } 730 731 return true; 732 } 733 734 735 /* 736 * Picture 737 * ------- 738 * 739 * Semantics of nexthop is very messy by historical reasons. 740 * We have to take into account, that: 741 * a) gateway can be actually local interface address, 742 * so that gatewayed route is direct. 743 * b) gateway must be on-link address, possibly 744 * described not by an ifaddr, but also by a direct route. 745 * c) If both gateway and interface are specified, they should not 746 * contradict. 747 * d) If we use tunnel routes, gateway could be not on-link. 748 * 749 * Attempt to reconcile all of these (alas, self-contradictory) conditions 750 * results in pretty ugly and hairy code with obscure logic. 751 * 752 * I chose to generalized it instead, so that the size 753 * of code does not increase practically, but it becomes 754 * much more general. 755 * Every prefix is assigned a "scope" value: "host" is local address, 756 * "link" is direct route, 757 * [ ... "site" ... "interior" ... ] 758 * and "universe" is true gateway route with global meaning. 759 * 760 * Every prefix refers to a set of "nexthop"s (gw, oif), 761 * where gw must have narrower scope. This recursion stops 762 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 763 * which means that gw is forced to be on link. 764 * 765 * Code is still hairy, but now it is apparently logically 766 * consistent and very flexible. F.e. as by-product it allows 767 * to co-exists in peace independent exterior and interior 768 * routing processes. 769 * 770 * Normally it looks as following. 771 * 772 * {universe prefix} -> (gw, oif) [scope link] 773 * | 774 * |-> {link prefix} -> (gw, oif) [scope local] 775 * | 776 * |-> {local prefix} (terminal node) 777 */ 778 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh, 779 struct netlink_ext_ack *extack) 780 { 781 int err = 0; 782 struct net *net; 783 struct net_device *dev; 784 785 net = cfg->fc_nlinfo.nl_net; 786 if (nh->nh_gw) { 787 struct fib_result res; 788 789 if (nh->nh_flags & RTNH_F_ONLINK) { 790 unsigned int addr_type; 791 792 if (cfg->fc_scope >= RT_SCOPE_LINK) { 793 NL_SET_ERR_MSG(extack, 794 "Nexthop has invalid scope"); 795 return -EINVAL; 796 } 797 dev = __dev_get_by_index(net, nh->nh_oif); 798 if (!dev) { 799 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 800 return -ENODEV; 801 } 802 if (!(dev->flags & IFF_UP)) { 803 NL_SET_ERR_MSG(extack, 804 "Nexthop device is not up"); 805 return -ENETDOWN; 806 } 807 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 808 if (addr_type != RTN_UNICAST) { 809 NL_SET_ERR_MSG(extack, 810 "Nexthop has invalid gateway"); 811 return -EINVAL; 812 } 813 if (!netif_carrier_ok(dev)) 814 nh->nh_flags |= RTNH_F_LINKDOWN; 815 nh->nh_dev = dev; 816 dev_hold(dev); 817 nh->nh_scope = RT_SCOPE_LINK; 818 return 0; 819 } 820 rcu_read_lock(); 821 { 822 struct fib_table *tbl = NULL; 823 struct flowi4 fl4 = { 824 .daddr = nh->nh_gw, 825 .flowi4_scope = cfg->fc_scope + 1, 826 .flowi4_oif = nh->nh_oif, 827 .flowi4_iif = LOOPBACK_IFINDEX, 828 }; 829 830 /* It is not necessary, but requires a bit of thinking */ 831 if (fl4.flowi4_scope < RT_SCOPE_LINK) 832 fl4.flowi4_scope = RT_SCOPE_LINK; 833 834 if (cfg->fc_table) 835 tbl = fib_get_table(net, cfg->fc_table); 836 837 if (tbl) 838 err = fib_table_lookup(tbl, &fl4, &res, 839 FIB_LOOKUP_IGNORE_LINKSTATE | 840 FIB_LOOKUP_NOREF); 841 842 /* on error or if no table given do full lookup. This 843 * is needed for example when nexthops are in the local 844 * table rather than the given table 845 */ 846 if (!tbl || err) { 847 err = fib_lookup(net, &fl4, &res, 848 FIB_LOOKUP_IGNORE_LINKSTATE); 849 } 850 851 if (err) { 852 NL_SET_ERR_MSG(extack, 853 "Nexthop has invalid gateway"); 854 rcu_read_unlock(); 855 return err; 856 } 857 } 858 err = -EINVAL; 859 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 860 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 861 goto out; 862 } 863 nh->nh_scope = res.scope; 864 nh->nh_oif = FIB_RES_OIF(res); 865 nh->nh_dev = dev = FIB_RES_DEV(res); 866 if (!dev) { 867 NL_SET_ERR_MSG(extack, 868 "No egress device for nexthop gateway"); 869 goto out; 870 } 871 dev_hold(dev); 872 if (!netif_carrier_ok(dev)) 873 nh->nh_flags |= RTNH_F_LINKDOWN; 874 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 875 } else { 876 struct in_device *in_dev; 877 878 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 879 NL_SET_ERR_MSG(extack, 880 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 881 return -EINVAL; 882 } 883 rcu_read_lock(); 884 err = -ENODEV; 885 in_dev = inetdev_by_index(net, nh->nh_oif); 886 if (!in_dev) 887 goto out; 888 err = -ENETDOWN; 889 if (!(in_dev->dev->flags & IFF_UP)) { 890 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 891 goto out; 892 } 893 nh->nh_dev = in_dev->dev; 894 dev_hold(nh->nh_dev); 895 nh->nh_scope = RT_SCOPE_HOST; 896 if (!netif_carrier_ok(nh->nh_dev)) 897 nh->nh_flags |= RTNH_F_LINKDOWN; 898 err = 0; 899 } 900 out: 901 rcu_read_unlock(); 902 return err; 903 } 904 905 static inline unsigned int fib_laddr_hashfn(__be32 val) 906 { 907 unsigned int mask = (fib_info_hash_size - 1); 908 909 return ((__force u32)val ^ 910 ((__force u32)val >> 7) ^ 911 ((__force u32)val >> 14)) & mask; 912 } 913 914 static struct hlist_head *fib_info_hash_alloc(int bytes) 915 { 916 if (bytes <= PAGE_SIZE) 917 return kzalloc(bytes, GFP_KERNEL); 918 else 919 return (struct hlist_head *) 920 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 921 get_order(bytes)); 922 } 923 924 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 925 { 926 if (!hash) 927 return; 928 929 if (bytes <= PAGE_SIZE) 930 kfree(hash); 931 else 932 free_pages((unsigned long) hash, get_order(bytes)); 933 } 934 935 static void fib_info_hash_move(struct hlist_head *new_info_hash, 936 struct hlist_head *new_laddrhash, 937 unsigned int new_size) 938 { 939 struct hlist_head *old_info_hash, *old_laddrhash; 940 unsigned int old_size = fib_info_hash_size; 941 unsigned int i, bytes; 942 943 spin_lock_bh(&fib_info_lock); 944 old_info_hash = fib_info_hash; 945 old_laddrhash = fib_info_laddrhash; 946 fib_info_hash_size = new_size; 947 948 for (i = 0; i < old_size; i++) { 949 struct hlist_head *head = &fib_info_hash[i]; 950 struct hlist_node *n; 951 struct fib_info *fi; 952 953 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 954 struct hlist_head *dest; 955 unsigned int new_hash; 956 957 new_hash = fib_info_hashfn(fi); 958 dest = &new_info_hash[new_hash]; 959 hlist_add_head(&fi->fib_hash, dest); 960 } 961 } 962 fib_info_hash = new_info_hash; 963 964 for (i = 0; i < old_size; i++) { 965 struct hlist_head *lhead = &fib_info_laddrhash[i]; 966 struct hlist_node *n; 967 struct fib_info *fi; 968 969 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 970 struct hlist_head *ldest; 971 unsigned int new_hash; 972 973 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 974 ldest = &new_laddrhash[new_hash]; 975 hlist_add_head(&fi->fib_lhash, ldest); 976 } 977 } 978 fib_info_laddrhash = new_laddrhash; 979 980 spin_unlock_bh(&fib_info_lock); 981 982 bytes = old_size * sizeof(struct hlist_head *); 983 fib_info_hash_free(old_info_hash, bytes); 984 fib_info_hash_free(old_laddrhash, bytes); 985 } 986 987 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 988 { 989 nh->nh_saddr = inet_select_addr(nh->nh_dev, 990 nh->nh_gw, 991 nh->nh_parent->fib_scope); 992 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 993 994 return nh->nh_saddr; 995 } 996 997 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 998 { 999 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1000 fib_prefsrc != cfg->fc_dst) { 1001 u32 tb_id = cfg->fc_table; 1002 int rc; 1003 1004 if (tb_id == RT_TABLE_MAIN) 1005 tb_id = RT_TABLE_LOCAL; 1006 1007 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1008 fib_prefsrc, tb_id); 1009 1010 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1011 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1012 fib_prefsrc, RT_TABLE_LOCAL); 1013 } 1014 1015 if (rc != RTN_LOCAL) 1016 return false; 1017 } 1018 return true; 1019 } 1020 1021 struct fib_info *fib_create_info(struct fib_config *cfg, 1022 struct netlink_ext_ack *extack) 1023 { 1024 int err; 1025 struct fib_info *fi = NULL; 1026 struct fib_info *ofi; 1027 int nhs = 1; 1028 struct net *net = cfg->fc_nlinfo.nl_net; 1029 1030 if (cfg->fc_type > RTN_MAX) 1031 goto err_inval; 1032 1033 /* Fast check to catch the most weird cases */ 1034 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1035 NL_SET_ERR_MSG(extack, "Invalid scope"); 1036 goto err_inval; 1037 } 1038 1039 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1040 NL_SET_ERR_MSG(extack, 1041 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1042 goto err_inval; 1043 } 1044 1045 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1046 if (cfg->fc_mp) { 1047 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1048 if (nhs == 0) 1049 goto err_inval; 1050 } 1051 #endif 1052 1053 err = -ENOBUFS; 1054 if (fib_info_cnt >= fib_info_hash_size) { 1055 unsigned int new_size = fib_info_hash_size << 1; 1056 struct hlist_head *new_info_hash; 1057 struct hlist_head *new_laddrhash; 1058 unsigned int bytes; 1059 1060 if (!new_size) 1061 new_size = 16; 1062 bytes = new_size * sizeof(struct hlist_head *); 1063 new_info_hash = fib_info_hash_alloc(bytes); 1064 new_laddrhash = fib_info_hash_alloc(bytes); 1065 if (!new_info_hash || !new_laddrhash) { 1066 fib_info_hash_free(new_info_hash, bytes); 1067 fib_info_hash_free(new_laddrhash, bytes); 1068 } else 1069 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1070 1071 if (!fib_info_hash_size) 1072 goto failure; 1073 } 1074 1075 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1076 if (!fi) 1077 goto failure; 1078 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1079 cfg->fc_mx_len); 1080 if (unlikely(IS_ERR(fi->fib_metrics))) { 1081 err = PTR_ERR(fi->fib_metrics); 1082 kfree(fi); 1083 return ERR_PTR(err); 1084 } 1085 1086 fib_info_cnt++; 1087 fi->fib_net = net; 1088 fi->fib_protocol = cfg->fc_protocol; 1089 fi->fib_scope = cfg->fc_scope; 1090 fi->fib_flags = cfg->fc_flags; 1091 fi->fib_priority = cfg->fc_priority; 1092 fi->fib_prefsrc = cfg->fc_prefsrc; 1093 fi->fib_type = cfg->fc_type; 1094 fi->fib_tb_id = cfg->fc_table; 1095 1096 fi->fib_nhs = nhs; 1097 change_nexthops(fi) { 1098 nexthop_nh->nh_parent = fi; 1099 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1100 if (!nexthop_nh->nh_pcpu_rth_output) 1101 goto failure; 1102 } endfor_nexthops(fi) 1103 1104 if (cfg->fc_mp) { 1105 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1106 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); 1107 if (err != 0) 1108 goto failure; 1109 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) { 1110 NL_SET_ERR_MSG(extack, 1111 "Nexthop device index does not match RTA_OIF"); 1112 goto err_inval; 1113 } 1114 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) { 1115 NL_SET_ERR_MSG(extack, 1116 "Nexthop gateway does not match RTA_GATEWAY"); 1117 goto err_inval; 1118 } 1119 #ifdef CONFIG_IP_ROUTE_CLASSID 1120 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) { 1121 NL_SET_ERR_MSG(extack, 1122 "Nexthop class id does not match RTA_FLOW"); 1123 goto err_inval; 1124 } 1125 #endif 1126 #else 1127 NL_SET_ERR_MSG(extack, 1128 "Multipath support not enabled in kernel"); 1129 goto err_inval; 1130 #endif 1131 } else { 1132 struct fib_nh *nh = fi->fib_nh; 1133 1134 if (cfg->fc_encap) { 1135 struct lwtunnel_state *lwtstate; 1136 1137 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) { 1138 NL_SET_ERR_MSG(extack, 1139 "LWT encap type not specified"); 1140 goto err_inval; 1141 } 1142 err = lwtunnel_build_state(cfg->fc_encap_type, 1143 cfg->fc_encap, AF_INET, cfg, 1144 &lwtstate, extack); 1145 if (err) 1146 goto failure; 1147 1148 nh->nh_lwtstate = lwtstate_get(lwtstate); 1149 } 1150 nh->nh_oif = cfg->fc_oif; 1151 nh->nh_gw = cfg->fc_gw; 1152 nh->nh_flags = cfg->fc_flags; 1153 #ifdef CONFIG_IP_ROUTE_CLASSID 1154 nh->nh_tclassid = cfg->fc_flow; 1155 if (nh->nh_tclassid) 1156 fi->fib_net->ipv4.fib_num_tclassid_users++; 1157 #endif 1158 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1159 nh->nh_weight = 1; 1160 #endif 1161 } 1162 1163 if (fib_props[cfg->fc_type].error) { 1164 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) { 1165 NL_SET_ERR_MSG(extack, 1166 "Gateway, device and multipath can not be specified for this route type"); 1167 goto err_inval; 1168 } 1169 goto link_it; 1170 } else { 1171 switch (cfg->fc_type) { 1172 case RTN_UNICAST: 1173 case RTN_LOCAL: 1174 case RTN_BROADCAST: 1175 case RTN_ANYCAST: 1176 case RTN_MULTICAST: 1177 break; 1178 default: 1179 NL_SET_ERR_MSG(extack, "Invalid route type"); 1180 goto err_inval; 1181 } 1182 } 1183 1184 if (cfg->fc_scope > RT_SCOPE_HOST) { 1185 NL_SET_ERR_MSG(extack, "Invalid scope"); 1186 goto err_inval; 1187 } 1188 1189 if (cfg->fc_scope == RT_SCOPE_HOST) { 1190 struct fib_nh *nh = fi->fib_nh; 1191 1192 /* Local address is added. */ 1193 if (nhs != 1) { 1194 NL_SET_ERR_MSG(extack, 1195 "Route with host scope can not have multiple nexthops"); 1196 goto err_inval; 1197 } 1198 if (nh->nh_gw) { 1199 NL_SET_ERR_MSG(extack, 1200 "Route with host scope can not have a gateway"); 1201 goto err_inval; 1202 } 1203 nh->nh_scope = RT_SCOPE_NOWHERE; 1204 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1205 err = -ENODEV; 1206 if (!nh->nh_dev) 1207 goto failure; 1208 } else { 1209 int linkdown = 0; 1210 1211 change_nexthops(fi) { 1212 err = fib_check_nh(cfg, nexthop_nh, extack); 1213 if (err != 0) 1214 goto failure; 1215 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1216 linkdown++; 1217 } endfor_nexthops(fi) 1218 if (linkdown == fi->fib_nhs) 1219 fi->fib_flags |= RTNH_F_LINKDOWN; 1220 } 1221 1222 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1223 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1224 goto err_inval; 1225 } 1226 1227 change_nexthops(fi) { 1228 fib_info_update_nh_saddr(net, nexthop_nh); 1229 } endfor_nexthops(fi) 1230 1231 fib_rebalance(fi); 1232 1233 link_it: 1234 ofi = fib_find_info(fi); 1235 if (ofi) { 1236 fi->fib_dead = 1; 1237 free_fib_info(fi); 1238 ofi->fib_treeref++; 1239 return ofi; 1240 } 1241 1242 fi->fib_treeref++; 1243 refcount_set(&fi->fib_clntref, 1); 1244 spin_lock_bh(&fib_info_lock); 1245 hlist_add_head(&fi->fib_hash, 1246 &fib_info_hash[fib_info_hashfn(fi)]); 1247 if (fi->fib_prefsrc) { 1248 struct hlist_head *head; 1249 1250 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1251 hlist_add_head(&fi->fib_lhash, head); 1252 } 1253 change_nexthops(fi) { 1254 struct hlist_head *head; 1255 unsigned int hash; 1256 1257 if (!nexthop_nh->nh_dev) 1258 continue; 1259 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1260 head = &fib_info_devhash[hash]; 1261 hlist_add_head(&nexthop_nh->nh_hash, head); 1262 } endfor_nexthops(fi) 1263 spin_unlock_bh(&fib_info_lock); 1264 return fi; 1265 1266 err_inval: 1267 err = -EINVAL; 1268 1269 failure: 1270 if (fi) { 1271 fi->fib_dead = 1; 1272 free_fib_info(fi); 1273 } 1274 1275 return ERR_PTR(err); 1276 } 1277 1278 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1279 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1280 struct fib_info *fi, unsigned int flags) 1281 { 1282 struct nlmsghdr *nlh; 1283 struct rtmsg *rtm; 1284 1285 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1286 if (!nlh) 1287 return -EMSGSIZE; 1288 1289 rtm = nlmsg_data(nlh); 1290 rtm->rtm_family = AF_INET; 1291 rtm->rtm_dst_len = dst_len; 1292 rtm->rtm_src_len = 0; 1293 rtm->rtm_tos = tos; 1294 if (tb_id < 256) 1295 rtm->rtm_table = tb_id; 1296 else 1297 rtm->rtm_table = RT_TABLE_COMPAT; 1298 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1299 goto nla_put_failure; 1300 rtm->rtm_type = type; 1301 rtm->rtm_flags = fi->fib_flags; 1302 rtm->rtm_scope = fi->fib_scope; 1303 rtm->rtm_protocol = fi->fib_protocol; 1304 1305 if (rtm->rtm_dst_len && 1306 nla_put_in_addr(skb, RTA_DST, dst)) 1307 goto nla_put_failure; 1308 if (fi->fib_priority && 1309 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1310 goto nla_put_failure; 1311 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1312 goto nla_put_failure; 1313 1314 if (fi->fib_prefsrc && 1315 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1316 goto nla_put_failure; 1317 if (fi->fib_nhs == 1) { 1318 if (fi->fib_nh->nh_gw && 1319 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1320 goto nla_put_failure; 1321 if (fi->fib_nh->nh_oif && 1322 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1323 goto nla_put_failure; 1324 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1325 struct in_device *in_dev; 1326 1327 rcu_read_lock(); 1328 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev); 1329 if (in_dev && 1330 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1331 rtm->rtm_flags |= RTNH_F_DEAD; 1332 rcu_read_unlock(); 1333 } 1334 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD) 1335 rtm->rtm_flags |= RTNH_F_OFFLOAD; 1336 #ifdef CONFIG_IP_ROUTE_CLASSID 1337 if (fi->fib_nh[0].nh_tclassid && 1338 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1339 goto nla_put_failure; 1340 #endif 1341 if (fi->fib_nh->nh_lwtstate && 1342 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0) 1343 goto nla_put_failure; 1344 } 1345 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1346 if (fi->fib_nhs > 1) { 1347 struct rtnexthop *rtnh; 1348 struct nlattr *mp; 1349 1350 mp = nla_nest_start(skb, RTA_MULTIPATH); 1351 if (!mp) 1352 goto nla_put_failure; 1353 1354 for_nexthops(fi) { 1355 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1356 if (!rtnh) 1357 goto nla_put_failure; 1358 1359 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1360 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1361 struct in_device *in_dev; 1362 1363 rcu_read_lock(); 1364 in_dev = __in_dev_get_rcu(nh->nh_dev); 1365 if (in_dev && 1366 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1367 rtnh->rtnh_flags |= RTNH_F_DEAD; 1368 rcu_read_unlock(); 1369 } 1370 rtnh->rtnh_hops = nh->nh_weight - 1; 1371 rtnh->rtnh_ifindex = nh->nh_oif; 1372 1373 if (nh->nh_gw && 1374 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1375 goto nla_put_failure; 1376 #ifdef CONFIG_IP_ROUTE_CLASSID 1377 if (nh->nh_tclassid && 1378 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1379 goto nla_put_failure; 1380 #endif 1381 if (nh->nh_lwtstate && 1382 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0) 1383 goto nla_put_failure; 1384 1385 /* length of rtnetlink header + attributes */ 1386 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1387 } endfor_nexthops(fi); 1388 1389 nla_nest_end(skb, mp); 1390 } 1391 #endif 1392 nlmsg_end(skb, nlh); 1393 return 0; 1394 1395 nla_put_failure: 1396 nlmsg_cancel(skb, nlh); 1397 return -EMSGSIZE; 1398 } 1399 1400 /* 1401 * Update FIB if: 1402 * - local address disappeared -> we must delete all the entries 1403 * referring to it. 1404 * - device went down -> we must shutdown all nexthops going via it. 1405 */ 1406 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1407 { 1408 int ret = 0; 1409 unsigned int hash = fib_laddr_hashfn(local); 1410 struct hlist_head *head = &fib_info_laddrhash[hash]; 1411 struct net *net = dev_net(dev); 1412 int tb_id = l3mdev_fib_table(dev); 1413 struct fib_info *fi; 1414 1415 if (!fib_info_laddrhash || local == 0) 1416 return 0; 1417 1418 hlist_for_each_entry(fi, head, fib_lhash) { 1419 if (!net_eq(fi->fib_net, net) || 1420 fi->fib_tb_id != tb_id) 1421 continue; 1422 if (fi->fib_prefsrc == local) { 1423 fi->fib_flags |= RTNH_F_DEAD; 1424 ret++; 1425 } 1426 } 1427 return ret; 1428 } 1429 1430 static int call_fib_nh_notifiers(struct fib_nh *fib_nh, 1431 enum fib_event_type event_type) 1432 { 1433 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev); 1434 struct fib_nh_notifier_info info = { 1435 .fib_nh = fib_nh, 1436 }; 1437 1438 switch (event_type) { 1439 case FIB_EVENT_NH_ADD: 1440 if (fib_nh->nh_flags & RTNH_F_DEAD) 1441 break; 1442 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1443 fib_nh->nh_flags & RTNH_F_LINKDOWN) 1444 break; 1445 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type, 1446 &info.info); 1447 case FIB_EVENT_NH_DEL: 1448 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1449 fib_nh->nh_flags & RTNH_F_LINKDOWN) || 1450 (fib_nh->nh_flags & RTNH_F_DEAD)) 1451 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), 1452 event_type, &info.info); 1453 default: 1454 break; 1455 } 1456 1457 return NOTIFY_DONE; 1458 } 1459 1460 /* Update the PMTU of exceptions when: 1461 * - the new MTU of the first hop becomes smaller than the PMTU 1462 * - the old MTU was the same as the PMTU, and it limited discovery of 1463 * larger MTUs on the path. With that limit raised, we can now 1464 * discover larger MTUs 1465 * A special case is locked exceptions, for which the PMTU is smaller 1466 * than the minimal accepted PMTU: 1467 * - if the new MTU is greater than the PMTU, don't make any change 1468 * - otherwise, unlock and set PMTU 1469 */ 1470 static void nh_update_mtu(struct fib_nh *nh, u32 new, u32 orig) 1471 { 1472 struct fnhe_hash_bucket *bucket; 1473 int i; 1474 1475 bucket = rcu_dereference_protected(nh->nh_exceptions, 1); 1476 if (!bucket) 1477 return; 1478 1479 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1480 struct fib_nh_exception *fnhe; 1481 1482 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1483 fnhe; 1484 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1485 if (fnhe->fnhe_mtu_locked) { 1486 if (new <= fnhe->fnhe_pmtu) { 1487 fnhe->fnhe_pmtu = new; 1488 fnhe->fnhe_mtu_locked = false; 1489 } 1490 } else if (new < fnhe->fnhe_pmtu || 1491 orig == fnhe->fnhe_pmtu) { 1492 fnhe->fnhe_pmtu = new; 1493 } 1494 } 1495 } 1496 } 1497 1498 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1499 { 1500 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1501 struct hlist_head *head = &fib_info_devhash[hash]; 1502 struct fib_nh *nh; 1503 1504 hlist_for_each_entry(nh, head, nh_hash) { 1505 if (nh->nh_dev == dev) 1506 nh_update_mtu(nh, dev->mtu, orig_mtu); 1507 } 1508 } 1509 1510 /* Event force Flags Description 1511 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1512 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1513 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1514 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1515 */ 1516 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1517 { 1518 int ret = 0; 1519 int scope = RT_SCOPE_NOWHERE; 1520 struct fib_info *prev_fi = NULL; 1521 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1522 struct hlist_head *head = &fib_info_devhash[hash]; 1523 struct fib_nh *nh; 1524 1525 if (force) 1526 scope = -1; 1527 1528 hlist_for_each_entry(nh, head, nh_hash) { 1529 struct fib_info *fi = nh->nh_parent; 1530 int dead; 1531 1532 BUG_ON(!fi->fib_nhs); 1533 if (nh->nh_dev != dev || fi == prev_fi) 1534 continue; 1535 prev_fi = fi; 1536 dead = 0; 1537 change_nexthops(fi) { 1538 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1539 dead++; 1540 else if (nexthop_nh->nh_dev == dev && 1541 nexthop_nh->nh_scope != scope) { 1542 switch (event) { 1543 case NETDEV_DOWN: 1544 case NETDEV_UNREGISTER: 1545 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1546 /* fall through */ 1547 case NETDEV_CHANGE: 1548 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1549 break; 1550 } 1551 call_fib_nh_notifiers(nexthop_nh, 1552 FIB_EVENT_NH_DEL); 1553 dead++; 1554 } 1555 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1556 if (event == NETDEV_UNREGISTER && 1557 nexthop_nh->nh_dev == dev) { 1558 dead = fi->fib_nhs; 1559 break; 1560 } 1561 #endif 1562 } endfor_nexthops(fi) 1563 if (dead == fi->fib_nhs) { 1564 switch (event) { 1565 case NETDEV_DOWN: 1566 case NETDEV_UNREGISTER: 1567 fi->fib_flags |= RTNH_F_DEAD; 1568 /* fall through */ 1569 case NETDEV_CHANGE: 1570 fi->fib_flags |= RTNH_F_LINKDOWN; 1571 break; 1572 } 1573 ret++; 1574 } 1575 1576 fib_rebalance(fi); 1577 } 1578 1579 return ret; 1580 } 1581 1582 /* Must be invoked inside of an RCU protected region. */ 1583 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1584 { 1585 struct fib_info *fi = NULL, *last_resort = NULL; 1586 struct hlist_head *fa_head = res->fa_head; 1587 struct fib_table *tb = res->table; 1588 u8 slen = 32 - res->prefixlen; 1589 int order = -1, last_idx = -1; 1590 struct fib_alias *fa, *fa1 = NULL; 1591 u32 last_prio = res->fi->fib_priority; 1592 u8 last_tos = 0; 1593 1594 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1595 struct fib_info *next_fi = fa->fa_info; 1596 1597 if (fa->fa_slen != slen) 1598 continue; 1599 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1600 continue; 1601 if (fa->tb_id != tb->tb_id) 1602 continue; 1603 if (next_fi->fib_priority > last_prio && 1604 fa->fa_tos == last_tos) { 1605 if (last_tos) 1606 continue; 1607 break; 1608 } 1609 if (next_fi->fib_flags & RTNH_F_DEAD) 1610 continue; 1611 last_tos = fa->fa_tos; 1612 last_prio = next_fi->fib_priority; 1613 1614 if (next_fi->fib_scope != res->scope || 1615 fa->fa_type != RTN_UNICAST) 1616 continue; 1617 if (!next_fi->fib_nh[0].nh_gw || 1618 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1619 continue; 1620 1621 fib_alias_accessed(fa); 1622 1623 if (!fi) { 1624 if (next_fi != res->fi) 1625 break; 1626 fa1 = fa; 1627 } else if (!fib_detect_death(fi, order, &last_resort, 1628 &last_idx, fa1->fa_default)) { 1629 fib_result_assign(res, fi); 1630 fa1->fa_default = order; 1631 goto out; 1632 } 1633 fi = next_fi; 1634 order++; 1635 } 1636 1637 if (order <= 0 || !fi) { 1638 if (fa1) 1639 fa1->fa_default = -1; 1640 goto out; 1641 } 1642 1643 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1644 fa1->fa_default)) { 1645 fib_result_assign(res, fi); 1646 fa1->fa_default = order; 1647 goto out; 1648 } 1649 1650 if (last_idx >= 0) 1651 fib_result_assign(res, last_resort); 1652 fa1->fa_default = last_idx; 1653 out: 1654 return; 1655 } 1656 1657 /* 1658 * Dead device goes up. We wake up dead nexthops. 1659 * It takes sense only on multipath routes. 1660 */ 1661 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1662 { 1663 struct fib_info *prev_fi; 1664 unsigned int hash; 1665 struct hlist_head *head; 1666 struct fib_nh *nh; 1667 int ret; 1668 1669 if (!(dev->flags & IFF_UP)) 1670 return 0; 1671 1672 if (nh_flags & RTNH_F_DEAD) { 1673 unsigned int flags = dev_get_flags(dev); 1674 1675 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1676 nh_flags |= RTNH_F_LINKDOWN; 1677 } 1678 1679 prev_fi = NULL; 1680 hash = fib_devindex_hashfn(dev->ifindex); 1681 head = &fib_info_devhash[hash]; 1682 ret = 0; 1683 1684 hlist_for_each_entry(nh, head, nh_hash) { 1685 struct fib_info *fi = nh->nh_parent; 1686 int alive; 1687 1688 BUG_ON(!fi->fib_nhs); 1689 if (nh->nh_dev != dev || fi == prev_fi) 1690 continue; 1691 1692 prev_fi = fi; 1693 alive = 0; 1694 change_nexthops(fi) { 1695 if (!(nexthop_nh->nh_flags & nh_flags)) { 1696 alive++; 1697 continue; 1698 } 1699 if (!nexthop_nh->nh_dev || 1700 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1701 continue; 1702 if (nexthop_nh->nh_dev != dev || 1703 !__in_dev_get_rtnl(dev)) 1704 continue; 1705 alive++; 1706 nexthop_nh->nh_flags &= ~nh_flags; 1707 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 1708 } endfor_nexthops(fi) 1709 1710 if (alive > 0) { 1711 fi->fib_flags &= ~nh_flags; 1712 ret++; 1713 } 1714 1715 fib_rebalance(fi); 1716 } 1717 1718 return ret; 1719 } 1720 1721 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1722 static bool fib_good_nh(const struct fib_nh *nh) 1723 { 1724 int state = NUD_REACHABLE; 1725 1726 if (nh->nh_scope == RT_SCOPE_LINK) { 1727 struct neighbour *n; 1728 1729 rcu_read_lock_bh(); 1730 1731 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1732 (__force u32)nh->nh_gw); 1733 if (n) 1734 state = n->nud_state; 1735 1736 rcu_read_unlock_bh(); 1737 } 1738 1739 return !!(state & NUD_VALID); 1740 } 1741 1742 void fib_select_multipath(struct fib_result *res, int hash) 1743 { 1744 struct fib_info *fi = res->fi; 1745 struct net *net = fi->fib_net; 1746 bool first = false; 1747 1748 for_nexthops(fi) { 1749 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 1750 if (!fib_good_nh(nh)) 1751 continue; 1752 if (!first) { 1753 res->nh_sel = nhsel; 1754 first = true; 1755 } 1756 } 1757 1758 if (hash > atomic_read(&nh->nh_upper_bound)) 1759 continue; 1760 1761 res->nh_sel = nhsel; 1762 return; 1763 } endfor_nexthops(fi); 1764 } 1765 #endif 1766 1767 void fib_select_path(struct net *net, struct fib_result *res, 1768 struct flowi4 *fl4, const struct sk_buff *skb) 1769 { 1770 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 1771 goto check_saddr; 1772 1773 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1774 if (res->fi->fib_nhs > 1) { 1775 int h = fib_multipath_hash(net, fl4, skb, NULL); 1776 1777 fib_select_multipath(res, h); 1778 } 1779 else 1780 #endif 1781 if (!res->prefixlen && 1782 res->table->tb_num_default > 1 && 1783 res->type == RTN_UNICAST) 1784 fib_select_default(fl4, res); 1785 1786 check_saddr: 1787 if (!fl4->saddr) 1788 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1789 } 1790