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/ip6_fib.h> 45 #include <net/netlink.h> 46 #include <net/rtnh.h> 47 #include <net/lwtunnel.h> 48 #include <net/fib_notifier.h> 49 #include <net/addrconf.h> 50 51 #include "fib_lookup.h" 52 53 static DEFINE_SPINLOCK(fib_info_lock); 54 static struct hlist_head *fib_info_hash; 55 static struct hlist_head *fib_info_laddrhash; 56 static unsigned int fib_info_hash_size; 57 static unsigned int fib_info_cnt; 58 59 #define DEVINDEX_HASHBITS 8 60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 62 63 #ifdef CONFIG_IP_ROUTE_MULTIPATH 64 65 #define for_nexthops(fi) { \ 66 int nhsel; const struct fib_nh *nh; \ 67 for (nhsel = 0, nh = (fi)->fib_nh; \ 68 nhsel < (fi)->fib_nhs; \ 69 nh++, nhsel++) 70 71 #define change_nexthops(fi) { \ 72 int nhsel; struct fib_nh *nexthop_nh; \ 73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 74 nhsel < (fi)->fib_nhs; \ 75 nexthop_nh++, nhsel++) 76 77 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 78 79 /* Hope, that gcc will optimize it to get rid of dummy loop */ 80 81 #define for_nexthops(fi) { \ 82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 83 for (nhsel = 0; nhsel < 1; nhsel++) 84 85 #define change_nexthops(fi) { \ 86 int nhsel; \ 87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 88 for (nhsel = 0; nhsel < 1; nhsel++) 89 90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 91 92 #define endfor_nexthops(fi) } 93 94 95 const struct fib_prop fib_props[RTN_MAX + 1] = { 96 [RTN_UNSPEC] = { 97 .error = 0, 98 .scope = RT_SCOPE_NOWHERE, 99 }, 100 [RTN_UNICAST] = { 101 .error = 0, 102 .scope = RT_SCOPE_UNIVERSE, 103 }, 104 [RTN_LOCAL] = { 105 .error = 0, 106 .scope = RT_SCOPE_HOST, 107 }, 108 [RTN_BROADCAST] = { 109 .error = 0, 110 .scope = RT_SCOPE_LINK, 111 }, 112 [RTN_ANYCAST] = { 113 .error = 0, 114 .scope = RT_SCOPE_LINK, 115 }, 116 [RTN_MULTICAST] = { 117 .error = 0, 118 .scope = RT_SCOPE_UNIVERSE, 119 }, 120 [RTN_BLACKHOLE] = { 121 .error = -EINVAL, 122 .scope = RT_SCOPE_UNIVERSE, 123 }, 124 [RTN_UNREACHABLE] = { 125 .error = -EHOSTUNREACH, 126 .scope = RT_SCOPE_UNIVERSE, 127 }, 128 [RTN_PROHIBIT] = { 129 .error = -EACCES, 130 .scope = RT_SCOPE_UNIVERSE, 131 }, 132 [RTN_THROW] = { 133 .error = -EAGAIN, 134 .scope = RT_SCOPE_UNIVERSE, 135 }, 136 [RTN_NAT] = { 137 .error = -EINVAL, 138 .scope = RT_SCOPE_NOWHERE, 139 }, 140 [RTN_XRESOLVE] = { 141 .error = -EINVAL, 142 .scope = RT_SCOPE_NOWHERE, 143 }, 144 }; 145 146 static void rt_fibinfo_free(struct rtable __rcu **rtp) 147 { 148 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 149 150 if (!rt) 151 return; 152 153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 154 * because we waited an RCU grace period before calling 155 * free_fib_info_rcu() 156 */ 157 158 dst_dev_put(&rt->dst); 159 dst_release_immediate(&rt->dst); 160 } 161 162 static void free_nh_exceptions(struct fib_nh *nh) 163 { 164 struct fnhe_hash_bucket *hash; 165 int i; 166 167 hash = rcu_dereference_protected(nh->nh_exceptions, 1); 168 if (!hash) 169 return; 170 for (i = 0; i < FNHE_HASH_SIZE; i++) { 171 struct fib_nh_exception *fnhe; 172 173 fnhe = rcu_dereference_protected(hash[i].chain, 1); 174 while (fnhe) { 175 struct fib_nh_exception *next; 176 177 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 178 179 rt_fibinfo_free(&fnhe->fnhe_rth_input); 180 rt_fibinfo_free(&fnhe->fnhe_rth_output); 181 182 kfree(fnhe); 183 184 fnhe = next; 185 } 186 } 187 kfree(hash); 188 } 189 190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 191 { 192 int cpu; 193 194 if (!rtp) 195 return; 196 197 for_each_possible_cpu(cpu) { 198 struct rtable *rt; 199 200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 201 if (rt) { 202 dst_dev_put(&rt->dst); 203 dst_release_immediate(&rt->dst); 204 } 205 } 206 free_percpu(rtp); 207 } 208 209 void fib_nh_common_release(struct fib_nh_common *nhc) 210 { 211 if (nhc->nhc_dev) 212 dev_put(nhc->nhc_dev); 213 214 lwtstate_put(nhc->nhc_lwtstate); 215 } 216 EXPORT_SYMBOL_GPL(fib_nh_common_release); 217 218 void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 219 { 220 #ifdef CONFIG_IP_ROUTE_CLASSID 221 if (fib_nh->nh_tclassid) 222 net->ipv4.fib_num_tclassid_users--; 223 #endif 224 fib_nh_common_release(&fib_nh->nh_common); 225 free_nh_exceptions(fib_nh); 226 rt_fibinfo_free_cpus(fib_nh->nh_pcpu_rth_output); 227 rt_fibinfo_free(&fib_nh->nh_rth_input); 228 } 229 230 /* Release a nexthop info record */ 231 static void free_fib_info_rcu(struct rcu_head *head) 232 { 233 struct fib_info *fi = container_of(head, struct fib_info, rcu); 234 235 change_nexthops(fi) { 236 fib_nh_release(fi->fib_net, nexthop_nh); 237 } endfor_nexthops(fi); 238 239 ip_fib_metrics_put(fi->fib_metrics); 240 241 kfree(fi); 242 } 243 244 void free_fib_info(struct fib_info *fi) 245 { 246 if (fi->fib_dead == 0) { 247 pr_warn("Freeing alive fib_info %p\n", fi); 248 return; 249 } 250 fib_info_cnt--; 251 252 call_rcu(&fi->rcu, free_fib_info_rcu); 253 } 254 EXPORT_SYMBOL_GPL(free_fib_info); 255 256 void fib_release_info(struct fib_info *fi) 257 { 258 spin_lock_bh(&fib_info_lock); 259 if (fi && --fi->fib_treeref == 0) { 260 hlist_del(&fi->fib_hash); 261 if (fi->fib_prefsrc) 262 hlist_del(&fi->fib_lhash); 263 change_nexthops(fi) { 264 if (!nexthop_nh->fib_nh_dev) 265 continue; 266 hlist_del(&nexthop_nh->nh_hash); 267 } endfor_nexthops(fi) 268 fi->fib_dead = 1; 269 fib_info_put(fi); 270 } 271 spin_unlock_bh(&fib_info_lock); 272 } 273 274 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 275 { 276 const struct fib_nh *onh = ofi->fib_nh; 277 278 for_nexthops(fi) { 279 if (nh->fib_nh_oif != onh->fib_nh_oif || 280 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 281 nh->fib_nh_scope != onh->fib_nh_scope || 282 #ifdef CONFIG_IP_ROUTE_MULTIPATH 283 nh->fib_nh_weight != onh->fib_nh_weight || 284 #endif 285 #ifdef CONFIG_IP_ROUTE_CLASSID 286 nh->nh_tclassid != onh->nh_tclassid || 287 #endif 288 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 289 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 290 return -1; 291 292 if (nh->fib_nh_gw_family == AF_INET && 293 nh->fib_nh_gw4 != onh->fib_nh_gw4) 294 return -1; 295 296 if (nh->fib_nh_gw_family == AF_INET6 && 297 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 298 return -1; 299 300 onh++; 301 } endfor_nexthops(fi); 302 return 0; 303 } 304 305 static inline unsigned int fib_devindex_hashfn(unsigned int val) 306 { 307 unsigned int mask = DEVINDEX_HASHSIZE - 1; 308 309 return (val ^ 310 (val >> DEVINDEX_HASHBITS) ^ 311 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 312 } 313 314 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 315 { 316 unsigned int mask = (fib_info_hash_size - 1); 317 unsigned int val = fi->fib_nhs; 318 319 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 320 val ^= (__force u32)fi->fib_prefsrc; 321 val ^= fi->fib_priority; 322 for_nexthops(fi) { 323 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 324 } endfor_nexthops(fi) 325 326 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 327 } 328 329 static struct fib_info *fib_find_info(const struct fib_info *nfi) 330 { 331 struct hlist_head *head; 332 struct fib_info *fi; 333 unsigned int hash; 334 335 hash = fib_info_hashfn(nfi); 336 head = &fib_info_hash[hash]; 337 338 hlist_for_each_entry(fi, head, fib_hash) { 339 if (!net_eq(fi->fib_net, nfi->fib_net)) 340 continue; 341 if (fi->fib_nhs != nfi->fib_nhs) 342 continue; 343 if (nfi->fib_protocol == fi->fib_protocol && 344 nfi->fib_scope == fi->fib_scope && 345 nfi->fib_prefsrc == fi->fib_prefsrc && 346 nfi->fib_priority == fi->fib_priority && 347 nfi->fib_type == fi->fib_type && 348 memcmp(nfi->fib_metrics, fi->fib_metrics, 349 sizeof(u32) * RTAX_MAX) == 0 && 350 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 351 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 352 return fi; 353 } 354 355 return NULL; 356 } 357 358 /* Check, that the gateway is already configured. 359 * Used only by redirect accept routine. 360 */ 361 int ip_fib_check_default(__be32 gw, struct net_device *dev) 362 { 363 struct hlist_head *head; 364 struct fib_nh *nh; 365 unsigned int hash; 366 367 spin_lock(&fib_info_lock); 368 369 hash = fib_devindex_hashfn(dev->ifindex); 370 head = &fib_info_devhash[hash]; 371 hlist_for_each_entry(nh, head, nh_hash) { 372 if (nh->fib_nh_dev == dev && 373 nh->fib_nh_gw4 == gw && 374 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 375 spin_unlock(&fib_info_lock); 376 return 0; 377 } 378 } 379 380 spin_unlock(&fib_info_lock); 381 382 return -1; 383 } 384 385 static inline size_t fib_nlmsg_size(struct fib_info *fi) 386 { 387 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 388 + nla_total_size(4) /* RTA_TABLE */ 389 + nla_total_size(4) /* RTA_DST */ 390 + nla_total_size(4) /* RTA_PRIORITY */ 391 + nla_total_size(4) /* RTA_PREFSRC */ 392 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 393 394 /* space for nested metrics */ 395 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 396 397 if (fi->fib_nhs) { 398 size_t nh_encapsize = 0; 399 /* Also handles the special case fib_nhs == 1 */ 400 401 /* each nexthop is packed in an attribute */ 402 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 403 404 /* may contain flow and gateway attribute */ 405 nhsize += 2 * nla_total_size(4); 406 407 /* grab encap info */ 408 for_nexthops(fi) { 409 if (nh->fib_nh_lws) { 410 /* RTA_ENCAP_TYPE */ 411 nh_encapsize += lwtunnel_get_encap_size( 412 nh->fib_nh_lws); 413 /* RTA_ENCAP */ 414 nh_encapsize += nla_total_size(2); 415 } 416 } endfor_nexthops(fi); 417 418 /* all nexthops are packed in a nested attribute */ 419 payload += nla_total_size((fi->fib_nhs * nhsize) + 420 nh_encapsize); 421 422 } 423 424 return payload; 425 } 426 427 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 428 int dst_len, u32 tb_id, const struct nl_info *info, 429 unsigned int nlm_flags) 430 { 431 struct sk_buff *skb; 432 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 433 int err = -ENOBUFS; 434 435 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 436 if (!skb) 437 goto errout; 438 439 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 440 fa->fa_type, key, dst_len, 441 fa->fa_tos, fa->fa_info, nlm_flags); 442 if (err < 0) { 443 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 444 WARN_ON(err == -EMSGSIZE); 445 kfree_skb(skb); 446 goto errout; 447 } 448 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 449 info->nlh, GFP_KERNEL); 450 return; 451 errout: 452 if (err < 0) 453 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 454 } 455 456 static int fib_detect_death(struct fib_info *fi, int order, 457 struct fib_info **last_resort, int *last_idx, 458 int dflt) 459 { 460 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 461 struct neighbour *n; 462 int state = NUD_NONE; 463 464 if (likely(nhc->nhc_gw_family == AF_INET)) 465 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 466 else if (nhc->nhc_gw_family == AF_INET6) 467 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 468 nhc->nhc_dev); 469 else 470 n = NULL; 471 472 if (n) { 473 state = n->nud_state; 474 neigh_release(n); 475 } else { 476 return 0; 477 } 478 if (state == NUD_REACHABLE) 479 return 0; 480 if ((state & NUD_VALID) && order != dflt) 481 return 0; 482 if ((state & NUD_VALID) || 483 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 484 *last_resort = fi; 485 *last_idx = order; 486 } 487 return 1; 488 } 489 490 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap, 491 u16 encap_type, void *cfg, gfp_t gfp_flags, 492 struct netlink_ext_ack *extack) 493 { 494 if (encap) { 495 struct lwtunnel_state *lwtstate; 496 int err; 497 498 if (encap_type == LWTUNNEL_ENCAP_NONE) { 499 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 500 return -EINVAL; 501 } 502 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family, 503 cfg, &lwtstate, extack); 504 if (err) 505 return err; 506 507 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 508 } 509 510 return 0; 511 } 512 EXPORT_SYMBOL_GPL(fib_nh_common_init); 513 514 int fib_nh_init(struct net *net, struct fib_nh *nh, 515 struct fib_config *cfg, int nh_weight, 516 struct netlink_ext_ack *extack) 517 { 518 int err = -ENOMEM; 519 520 nh->fib_nh_family = AF_INET; 521 522 nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 523 if (!nh->nh_pcpu_rth_output) 524 goto err_out; 525 526 err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap, 527 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 528 if (err) 529 goto init_failure; 530 531 nh->fib_nh_oif = cfg->fc_oif; 532 nh->fib_nh_gw_family = cfg->fc_gw_family; 533 if (cfg->fc_gw_family == AF_INET) 534 nh->fib_nh_gw4 = cfg->fc_gw4; 535 else if (cfg->fc_gw_family == AF_INET6) 536 nh->fib_nh_gw6 = cfg->fc_gw6; 537 538 nh->fib_nh_flags = cfg->fc_flags; 539 540 #ifdef CONFIG_IP_ROUTE_CLASSID 541 nh->nh_tclassid = cfg->fc_flow; 542 if (nh->nh_tclassid) 543 net->ipv4.fib_num_tclassid_users++; 544 #endif 545 #ifdef CONFIG_IP_ROUTE_MULTIPATH 546 nh->fib_nh_weight = nh_weight; 547 #endif 548 return 0; 549 550 init_failure: 551 rt_fibinfo_free_cpus(nh->nh_pcpu_rth_output); 552 nh->nh_pcpu_rth_output = NULL; 553 err_out: 554 return err; 555 } 556 557 #ifdef CONFIG_IP_ROUTE_MULTIPATH 558 559 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 560 struct netlink_ext_ack *extack) 561 { 562 int nhs = 0; 563 564 while (rtnh_ok(rtnh, remaining)) { 565 nhs++; 566 rtnh = rtnh_next(rtnh, &remaining); 567 } 568 569 /* leftover implies invalid nexthop configuration, discard it */ 570 if (remaining > 0) { 571 NL_SET_ERR_MSG(extack, 572 "Invalid nexthop configuration - extra data after nexthops"); 573 nhs = 0; 574 } 575 576 return nhs; 577 } 578 579 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 580 int remaining, struct fib_config *cfg, 581 struct netlink_ext_ack *extack) 582 { 583 struct net *net = fi->fib_net; 584 struct fib_config fib_cfg; 585 int ret; 586 587 change_nexthops(fi) { 588 int attrlen; 589 590 memset(&fib_cfg, 0, sizeof(fib_cfg)); 591 592 if (!rtnh_ok(rtnh, remaining)) { 593 NL_SET_ERR_MSG(extack, 594 "Invalid nexthop configuration - extra data after nexthop"); 595 return -EINVAL; 596 } 597 598 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 599 NL_SET_ERR_MSG(extack, 600 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 601 return -EINVAL; 602 } 603 604 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 605 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 606 607 attrlen = rtnh_attrlen(rtnh); 608 if (attrlen > 0) { 609 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 610 611 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 612 nlav = nla_find(attrs, attrlen, RTA_VIA); 613 if (nla && nlav) { 614 NL_SET_ERR_MSG(extack, 615 "Nexthop configuration can not contain both GATEWAY and VIA"); 616 return -EINVAL; 617 } 618 if (nla) { 619 fib_cfg.fc_gw4 = nla_get_in_addr(nla); 620 if (fib_cfg.fc_gw4) 621 fib_cfg.fc_gw_family = AF_INET; 622 } else if (nlav) { 623 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 624 if (ret) 625 goto errout; 626 } 627 628 nla = nla_find(attrs, attrlen, RTA_FLOW); 629 if (nla) 630 fib_cfg.fc_flow = nla_get_u32(nla); 631 632 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 633 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 634 if (nla) 635 fib_cfg.fc_encap_type = nla_get_u16(nla); 636 } 637 638 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 639 rtnh->rtnh_hops + 1, extack); 640 if (ret) 641 goto errout; 642 643 rtnh = rtnh_next(rtnh, &remaining); 644 } endfor_nexthops(fi); 645 646 ret = -EINVAL; 647 if (cfg->fc_oif && fi->fib_nh->fib_nh_oif != cfg->fc_oif) { 648 NL_SET_ERR_MSG(extack, 649 "Nexthop device index does not match RTA_OIF"); 650 goto errout; 651 } 652 if (cfg->fc_gw_family) { 653 if (cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family || 654 (cfg->fc_gw_family == AF_INET && 655 fi->fib_nh->fib_nh_gw4 != cfg->fc_gw4) || 656 (cfg->fc_gw_family == AF_INET6 && 657 ipv6_addr_cmp(&fi->fib_nh->fib_nh_gw6, &cfg->fc_gw6))) { 658 NL_SET_ERR_MSG(extack, 659 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 660 goto errout; 661 } 662 } 663 #ifdef CONFIG_IP_ROUTE_CLASSID 664 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) { 665 NL_SET_ERR_MSG(extack, 666 "Nexthop class id does not match RTA_FLOW"); 667 goto errout; 668 } 669 #endif 670 ret = 0; 671 errout: 672 return ret; 673 } 674 675 static void fib_rebalance(struct fib_info *fi) 676 { 677 int total; 678 int w; 679 680 if (fi->fib_nhs < 2) 681 return; 682 683 total = 0; 684 for_nexthops(fi) { 685 if (nh->fib_nh_flags & RTNH_F_DEAD) 686 continue; 687 688 if (ip_ignore_linkdown(nh->fib_nh_dev) && 689 nh->fib_nh_flags & RTNH_F_LINKDOWN) 690 continue; 691 692 total += nh->fib_nh_weight; 693 } endfor_nexthops(fi); 694 695 w = 0; 696 change_nexthops(fi) { 697 int upper_bound; 698 699 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 700 upper_bound = -1; 701 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 702 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 703 upper_bound = -1; 704 } else { 705 w += nexthop_nh->fib_nh_weight; 706 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 707 total) - 1; 708 } 709 710 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 711 } endfor_nexthops(fi); 712 } 713 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 714 715 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 716 int remaining, struct fib_config *cfg, 717 struct netlink_ext_ack *extack) 718 { 719 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 720 721 return -EINVAL; 722 } 723 724 #define fib_rebalance(fi) do { } while (0) 725 726 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 727 728 static int fib_encap_match(u16 encap_type, 729 struct nlattr *encap, 730 const struct fib_nh *nh, 731 const struct fib_config *cfg, 732 struct netlink_ext_ack *extack) 733 { 734 struct lwtunnel_state *lwtstate; 735 int ret, result = 0; 736 737 if (encap_type == LWTUNNEL_ENCAP_NONE) 738 return 0; 739 740 ret = lwtunnel_build_state(encap_type, encap, AF_INET, 741 cfg, &lwtstate, extack); 742 if (!ret) { 743 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 744 lwtstate_free(lwtstate); 745 } 746 747 return result; 748 } 749 750 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, 751 struct netlink_ext_ack *extack) 752 { 753 #ifdef CONFIG_IP_ROUTE_MULTIPATH 754 struct rtnexthop *rtnh; 755 int remaining; 756 #endif 757 758 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 759 return 1; 760 761 if (cfg->fc_oif || cfg->fc_gw_family) { 762 if (cfg->fc_encap) { 763 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap, 764 fi->fib_nh, cfg, extack)) 765 return 1; 766 } 767 #ifdef CONFIG_IP_ROUTE_CLASSID 768 if (cfg->fc_flow && 769 cfg->fc_flow != fi->fib_nh->nh_tclassid) 770 return 1; 771 #endif 772 if ((cfg->fc_oif && cfg->fc_oif != fi->fib_nh->fib_nh_oif) || 773 (cfg->fc_gw_family && 774 cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family)) 775 return 1; 776 777 if (cfg->fc_gw_family == AF_INET && 778 cfg->fc_gw4 != fi->fib_nh->fib_nh_gw4) 779 return 1; 780 781 if (cfg->fc_gw_family == AF_INET6 && 782 ipv6_addr_cmp(&cfg->fc_gw6, &fi->fib_nh->fib_nh_gw6)) 783 return 1; 784 785 return 0; 786 } 787 788 #ifdef CONFIG_IP_ROUTE_MULTIPATH 789 if (!cfg->fc_mp) 790 return 0; 791 792 rtnh = cfg->fc_mp; 793 remaining = cfg->fc_mp_len; 794 795 for_nexthops(fi) { 796 int attrlen; 797 798 if (!rtnh_ok(rtnh, remaining)) 799 return -EINVAL; 800 801 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 802 return 1; 803 804 attrlen = rtnh_attrlen(rtnh); 805 if (attrlen > 0) { 806 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 807 808 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 809 nlav = nla_find(attrs, attrlen, RTA_VIA); 810 if (nla && nlav) { 811 NL_SET_ERR_MSG(extack, 812 "Nexthop configuration can not contain both GATEWAY and VIA"); 813 return -EINVAL; 814 } 815 816 if (nla) { 817 if (nh->fib_nh_gw_family != AF_INET || 818 nla_get_in_addr(nla) != nh->fib_nh_gw4) 819 return 1; 820 } else if (nlav) { 821 struct fib_config cfg2; 822 int err; 823 824 err = fib_gw_from_via(&cfg2, nlav, extack); 825 if (err) 826 return err; 827 828 switch (nh->fib_nh_gw_family) { 829 case AF_INET: 830 if (cfg2.fc_gw_family != AF_INET || 831 cfg2.fc_gw4 != nh->fib_nh_gw4) 832 return 1; 833 break; 834 case AF_INET6: 835 if (cfg2.fc_gw_family != AF_INET6 || 836 ipv6_addr_cmp(&cfg2.fc_gw6, 837 &nh->fib_nh_gw6)) 838 return 1; 839 break; 840 } 841 } 842 843 #ifdef CONFIG_IP_ROUTE_CLASSID 844 nla = nla_find(attrs, attrlen, RTA_FLOW); 845 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 846 return 1; 847 #endif 848 } 849 850 rtnh = rtnh_next(rtnh, &remaining); 851 } endfor_nexthops(fi); 852 #endif 853 return 0; 854 } 855 856 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 857 { 858 struct nlattr *nla; 859 int remaining; 860 861 if (!cfg->fc_mx) 862 return true; 863 864 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 865 int type = nla_type(nla); 866 u32 fi_val, val; 867 868 if (!type) 869 continue; 870 if (type > RTAX_MAX) 871 return false; 872 873 if (type == RTAX_CC_ALGO) { 874 char tmp[TCP_CA_NAME_MAX]; 875 bool ecn_ca = false; 876 877 nla_strlcpy(tmp, nla, sizeof(tmp)); 878 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 879 } else { 880 if (nla_len(nla) != sizeof(u32)) 881 return false; 882 val = nla_get_u32(nla); 883 } 884 885 fi_val = fi->fib_metrics->metrics[type - 1]; 886 if (type == RTAX_FEATURES) 887 fi_val &= ~DST_FEATURE_ECN_CA; 888 889 if (fi_val != val) 890 return false; 891 } 892 893 return true; 894 } 895 896 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 897 u32 table, struct netlink_ext_ack *extack) 898 { 899 struct fib6_config cfg = { 900 .fc_table = table, 901 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 902 .fc_ifindex = nh->fib_nh_oif, 903 .fc_gateway = nh->fib_nh_gw6, 904 }; 905 struct fib6_nh fib6_nh = {}; 906 int err; 907 908 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 909 if (!err) { 910 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 911 dev_hold(nh->fib_nh_dev); 912 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 913 nh->fib_nh_scope = RT_SCOPE_LINK; 914 915 ipv6_stub->fib6_nh_release(&fib6_nh); 916 } 917 918 return err; 919 } 920 921 /* 922 * Picture 923 * ------- 924 * 925 * Semantics of nexthop is very messy by historical reasons. 926 * We have to take into account, that: 927 * a) gateway can be actually local interface address, 928 * so that gatewayed route is direct. 929 * b) gateway must be on-link address, possibly 930 * described not by an ifaddr, but also by a direct route. 931 * c) If both gateway and interface are specified, they should not 932 * contradict. 933 * d) If we use tunnel routes, gateway could be not on-link. 934 * 935 * Attempt to reconcile all of these (alas, self-contradictory) conditions 936 * results in pretty ugly and hairy code with obscure logic. 937 * 938 * I chose to generalized it instead, so that the size 939 * of code does not increase practically, but it becomes 940 * much more general. 941 * Every prefix is assigned a "scope" value: "host" is local address, 942 * "link" is direct route, 943 * [ ... "site" ... "interior" ... ] 944 * and "universe" is true gateway route with global meaning. 945 * 946 * Every prefix refers to a set of "nexthop"s (gw, oif), 947 * where gw must have narrower scope. This recursion stops 948 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 949 * which means that gw is forced to be on link. 950 * 951 * Code is still hairy, but now it is apparently logically 952 * consistent and very flexible. F.e. as by-product it allows 953 * to co-exists in peace independent exterior and interior 954 * routing processes. 955 * 956 * Normally it looks as following. 957 * 958 * {universe prefix} -> (gw, oif) [scope link] 959 * | 960 * |-> {link prefix} -> (gw, oif) [scope local] 961 * | 962 * |-> {local prefix} (terminal node) 963 */ 964 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 965 u8 scope, struct netlink_ext_ack *extack) 966 { 967 struct net_device *dev; 968 struct fib_result res; 969 int err; 970 971 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 972 unsigned int addr_type; 973 974 if (scope >= RT_SCOPE_LINK) { 975 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 976 return -EINVAL; 977 } 978 dev = __dev_get_by_index(net, nh->fib_nh_oif); 979 if (!dev) { 980 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 981 return -ENODEV; 982 } 983 if (!(dev->flags & IFF_UP)) { 984 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 985 return -ENETDOWN; 986 } 987 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 988 if (addr_type != RTN_UNICAST) { 989 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 990 return -EINVAL; 991 } 992 if (!netif_carrier_ok(dev)) 993 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 994 nh->fib_nh_dev = dev; 995 dev_hold(dev); 996 nh->fib_nh_scope = RT_SCOPE_LINK; 997 return 0; 998 } 999 rcu_read_lock(); 1000 { 1001 struct fib_table *tbl = NULL; 1002 struct flowi4 fl4 = { 1003 .daddr = nh->fib_nh_gw4, 1004 .flowi4_scope = scope + 1, 1005 .flowi4_oif = nh->fib_nh_oif, 1006 .flowi4_iif = LOOPBACK_IFINDEX, 1007 }; 1008 1009 /* It is not necessary, but requires a bit of thinking */ 1010 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1011 fl4.flowi4_scope = RT_SCOPE_LINK; 1012 1013 if (table) 1014 tbl = fib_get_table(net, table); 1015 1016 if (tbl) 1017 err = fib_table_lookup(tbl, &fl4, &res, 1018 FIB_LOOKUP_IGNORE_LINKSTATE | 1019 FIB_LOOKUP_NOREF); 1020 1021 /* on error or if no table given do full lookup. This 1022 * is needed for example when nexthops are in the local 1023 * table rather than the given table 1024 */ 1025 if (!tbl || err) { 1026 err = fib_lookup(net, &fl4, &res, 1027 FIB_LOOKUP_IGNORE_LINKSTATE); 1028 } 1029 1030 if (err) { 1031 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1032 goto out; 1033 } 1034 } 1035 1036 err = -EINVAL; 1037 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1038 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1039 goto out; 1040 } 1041 nh->fib_nh_scope = res.scope; 1042 nh->fib_nh_oif = FIB_RES_OIF(res); 1043 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1044 if (!dev) { 1045 NL_SET_ERR_MSG(extack, 1046 "No egress device for nexthop gateway"); 1047 goto out; 1048 } 1049 dev_hold(dev); 1050 if (!netif_carrier_ok(dev)) 1051 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1052 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1053 out: 1054 rcu_read_unlock(); 1055 return err; 1056 } 1057 1058 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1059 struct netlink_ext_ack *extack) 1060 { 1061 struct in_device *in_dev; 1062 int err; 1063 1064 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1065 NL_SET_ERR_MSG(extack, 1066 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1067 return -EINVAL; 1068 } 1069 1070 rcu_read_lock(); 1071 1072 err = -ENODEV; 1073 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1074 if (!in_dev) 1075 goto out; 1076 err = -ENETDOWN; 1077 if (!(in_dev->dev->flags & IFF_UP)) { 1078 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1079 goto out; 1080 } 1081 1082 nh->fib_nh_dev = in_dev->dev; 1083 dev_hold(nh->fib_nh_dev); 1084 nh->fib_nh_scope = RT_SCOPE_HOST; 1085 if (!netif_carrier_ok(nh->fib_nh_dev)) 1086 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1087 err = 0; 1088 out: 1089 rcu_read_unlock(); 1090 return err; 1091 } 1092 1093 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh, 1094 struct netlink_ext_ack *extack) 1095 { 1096 struct net *net = cfg->fc_nlinfo.nl_net; 1097 u32 table = cfg->fc_table; 1098 int err; 1099 1100 if (nh->fib_nh_gw_family == AF_INET) 1101 err = fib_check_nh_v4_gw(net, nh, table, cfg->fc_scope, extack); 1102 else if (nh->fib_nh_gw_family == AF_INET6) 1103 err = fib_check_nh_v6_gw(net, nh, table, extack); 1104 else 1105 err = fib_check_nh_nongw(net, nh, extack); 1106 1107 return err; 1108 } 1109 1110 static inline unsigned int fib_laddr_hashfn(__be32 val) 1111 { 1112 unsigned int mask = (fib_info_hash_size - 1); 1113 1114 return ((__force u32)val ^ 1115 ((__force u32)val >> 7) ^ 1116 ((__force u32)val >> 14)) & mask; 1117 } 1118 1119 static struct hlist_head *fib_info_hash_alloc(int bytes) 1120 { 1121 if (bytes <= PAGE_SIZE) 1122 return kzalloc(bytes, GFP_KERNEL); 1123 else 1124 return (struct hlist_head *) 1125 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 1126 get_order(bytes)); 1127 } 1128 1129 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 1130 { 1131 if (!hash) 1132 return; 1133 1134 if (bytes <= PAGE_SIZE) 1135 kfree(hash); 1136 else 1137 free_pages((unsigned long) hash, get_order(bytes)); 1138 } 1139 1140 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1141 struct hlist_head *new_laddrhash, 1142 unsigned int new_size) 1143 { 1144 struct hlist_head *old_info_hash, *old_laddrhash; 1145 unsigned int old_size = fib_info_hash_size; 1146 unsigned int i, bytes; 1147 1148 spin_lock_bh(&fib_info_lock); 1149 old_info_hash = fib_info_hash; 1150 old_laddrhash = fib_info_laddrhash; 1151 fib_info_hash_size = new_size; 1152 1153 for (i = 0; i < old_size; i++) { 1154 struct hlist_head *head = &fib_info_hash[i]; 1155 struct hlist_node *n; 1156 struct fib_info *fi; 1157 1158 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1159 struct hlist_head *dest; 1160 unsigned int new_hash; 1161 1162 new_hash = fib_info_hashfn(fi); 1163 dest = &new_info_hash[new_hash]; 1164 hlist_add_head(&fi->fib_hash, dest); 1165 } 1166 } 1167 fib_info_hash = new_info_hash; 1168 1169 for (i = 0; i < old_size; i++) { 1170 struct hlist_head *lhead = &fib_info_laddrhash[i]; 1171 struct hlist_node *n; 1172 struct fib_info *fi; 1173 1174 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1175 struct hlist_head *ldest; 1176 unsigned int new_hash; 1177 1178 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 1179 ldest = &new_laddrhash[new_hash]; 1180 hlist_add_head(&fi->fib_lhash, ldest); 1181 } 1182 } 1183 fib_info_laddrhash = new_laddrhash; 1184 1185 spin_unlock_bh(&fib_info_lock); 1186 1187 bytes = old_size * sizeof(struct hlist_head *); 1188 fib_info_hash_free(old_info_hash, bytes); 1189 fib_info_hash_free(old_laddrhash, bytes); 1190 } 1191 1192 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 1193 { 1194 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, 1195 nh->fib_nh_gw4, 1196 nh->nh_parent->fib_scope); 1197 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1198 1199 return nh->nh_saddr; 1200 } 1201 1202 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1203 { 1204 struct fib_nh_common *nhc = res->nhc; 1205 struct fib_nh *nh; 1206 1207 if (res->fi->fib_prefsrc) 1208 return res->fi->fib_prefsrc; 1209 1210 nh = container_of(nhc, struct fib_nh, nh_common); 1211 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1212 return nh->nh_saddr; 1213 1214 return fib_info_update_nh_saddr(net, nh); 1215 } 1216 1217 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1218 { 1219 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1220 fib_prefsrc != cfg->fc_dst) { 1221 u32 tb_id = cfg->fc_table; 1222 int rc; 1223 1224 if (tb_id == RT_TABLE_MAIN) 1225 tb_id = RT_TABLE_LOCAL; 1226 1227 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1228 fib_prefsrc, tb_id); 1229 1230 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1231 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1232 fib_prefsrc, RT_TABLE_LOCAL); 1233 } 1234 1235 if (rc != RTN_LOCAL) 1236 return false; 1237 } 1238 return true; 1239 } 1240 1241 struct fib_info *fib_create_info(struct fib_config *cfg, 1242 struct netlink_ext_ack *extack) 1243 { 1244 int err; 1245 struct fib_info *fi = NULL; 1246 struct fib_info *ofi; 1247 int nhs = 1; 1248 struct net *net = cfg->fc_nlinfo.nl_net; 1249 1250 if (cfg->fc_type > RTN_MAX) 1251 goto err_inval; 1252 1253 /* Fast check to catch the most weird cases */ 1254 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1255 NL_SET_ERR_MSG(extack, "Invalid scope"); 1256 goto err_inval; 1257 } 1258 1259 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1260 NL_SET_ERR_MSG(extack, 1261 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1262 goto err_inval; 1263 } 1264 1265 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1266 if (cfg->fc_mp) { 1267 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1268 if (nhs == 0) 1269 goto err_inval; 1270 } 1271 #endif 1272 1273 err = -ENOBUFS; 1274 if (fib_info_cnt >= fib_info_hash_size) { 1275 unsigned int new_size = fib_info_hash_size << 1; 1276 struct hlist_head *new_info_hash; 1277 struct hlist_head *new_laddrhash; 1278 unsigned int bytes; 1279 1280 if (!new_size) 1281 new_size = 16; 1282 bytes = new_size * sizeof(struct hlist_head *); 1283 new_info_hash = fib_info_hash_alloc(bytes); 1284 new_laddrhash = fib_info_hash_alloc(bytes); 1285 if (!new_info_hash || !new_laddrhash) { 1286 fib_info_hash_free(new_info_hash, bytes); 1287 fib_info_hash_free(new_laddrhash, bytes); 1288 } else 1289 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1290 1291 if (!fib_info_hash_size) 1292 goto failure; 1293 } 1294 1295 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1296 if (!fi) 1297 goto failure; 1298 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1299 cfg->fc_mx_len, extack); 1300 if (unlikely(IS_ERR(fi->fib_metrics))) { 1301 err = PTR_ERR(fi->fib_metrics); 1302 kfree(fi); 1303 return ERR_PTR(err); 1304 } 1305 1306 fib_info_cnt++; 1307 fi->fib_net = net; 1308 fi->fib_protocol = cfg->fc_protocol; 1309 fi->fib_scope = cfg->fc_scope; 1310 fi->fib_flags = cfg->fc_flags; 1311 fi->fib_priority = cfg->fc_priority; 1312 fi->fib_prefsrc = cfg->fc_prefsrc; 1313 fi->fib_type = cfg->fc_type; 1314 fi->fib_tb_id = cfg->fc_table; 1315 1316 fi->fib_nhs = nhs; 1317 change_nexthops(fi) { 1318 nexthop_nh->nh_parent = fi; 1319 } endfor_nexthops(fi) 1320 1321 if (cfg->fc_mp) 1322 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); 1323 else 1324 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1325 1326 if (err != 0) 1327 goto failure; 1328 1329 if (fib_props[cfg->fc_type].error) { 1330 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1331 NL_SET_ERR_MSG(extack, 1332 "Gateway, device and multipath can not be specified for this route type"); 1333 goto err_inval; 1334 } 1335 goto link_it; 1336 } else { 1337 switch (cfg->fc_type) { 1338 case RTN_UNICAST: 1339 case RTN_LOCAL: 1340 case RTN_BROADCAST: 1341 case RTN_ANYCAST: 1342 case RTN_MULTICAST: 1343 break; 1344 default: 1345 NL_SET_ERR_MSG(extack, "Invalid route type"); 1346 goto err_inval; 1347 } 1348 } 1349 1350 if (cfg->fc_scope > RT_SCOPE_HOST) { 1351 NL_SET_ERR_MSG(extack, "Invalid scope"); 1352 goto err_inval; 1353 } 1354 1355 if (cfg->fc_scope == RT_SCOPE_HOST) { 1356 struct fib_nh *nh = fi->fib_nh; 1357 1358 /* Local address is added. */ 1359 if (nhs != 1) { 1360 NL_SET_ERR_MSG(extack, 1361 "Route with host scope can not have multiple nexthops"); 1362 goto err_inval; 1363 } 1364 if (nh->fib_nh_gw_family) { 1365 NL_SET_ERR_MSG(extack, 1366 "Route with host scope can not have a gateway"); 1367 goto err_inval; 1368 } 1369 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1370 nh->fib_nh_dev = dev_get_by_index(net, fi->fib_nh->fib_nh_oif); 1371 err = -ENODEV; 1372 if (!nh->fib_nh_dev) 1373 goto failure; 1374 } else { 1375 int linkdown = 0; 1376 1377 change_nexthops(fi) { 1378 err = fib_check_nh(cfg, nexthop_nh, extack); 1379 if (err != 0) 1380 goto failure; 1381 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1382 linkdown++; 1383 } endfor_nexthops(fi) 1384 if (linkdown == fi->fib_nhs) 1385 fi->fib_flags |= RTNH_F_LINKDOWN; 1386 } 1387 1388 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1389 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1390 goto err_inval; 1391 } 1392 1393 change_nexthops(fi) { 1394 fib_info_update_nh_saddr(net, nexthop_nh); 1395 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1396 fi->fib_nh_is_v6 = true; 1397 } endfor_nexthops(fi) 1398 1399 fib_rebalance(fi); 1400 1401 link_it: 1402 ofi = fib_find_info(fi); 1403 if (ofi) { 1404 fi->fib_dead = 1; 1405 free_fib_info(fi); 1406 ofi->fib_treeref++; 1407 return ofi; 1408 } 1409 1410 fi->fib_treeref++; 1411 refcount_set(&fi->fib_clntref, 1); 1412 spin_lock_bh(&fib_info_lock); 1413 hlist_add_head(&fi->fib_hash, 1414 &fib_info_hash[fib_info_hashfn(fi)]); 1415 if (fi->fib_prefsrc) { 1416 struct hlist_head *head; 1417 1418 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1419 hlist_add_head(&fi->fib_lhash, head); 1420 } 1421 change_nexthops(fi) { 1422 struct hlist_head *head; 1423 unsigned int hash; 1424 1425 if (!nexthop_nh->fib_nh_dev) 1426 continue; 1427 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex); 1428 head = &fib_info_devhash[hash]; 1429 hlist_add_head(&nexthop_nh->nh_hash, head); 1430 } endfor_nexthops(fi) 1431 spin_unlock_bh(&fib_info_lock); 1432 return fi; 1433 1434 err_inval: 1435 err = -EINVAL; 1436 1437 failure: 1438 if (fi) { 1439 fi->fib_dead = 1; 1440 free_fib_info(fi); 1441 } 1442 1443 return ERR_PTR(err); 1444 } 1445 1446 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1447 unsigned int *flags, bool skip_oif) 1448 { 1449 if (nhc->nhc_flags & RTNH_F_DEAD) 1450 *flags |= RTNH_F_DEAD; 1451 1452 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1453 *flags |= RTNH_F_LINKDOWN; 1454 1455 rcu_read_lock(); 1456 switch (nhc->nhc_family) { 1457 case AF_INET: 1458 if (ip_ignore_linkdown(nhc->nhc_dev)) 1459 *flags |= RTNH_F_DEAD; 1460 break; 1461 case AF_INET6: 1462 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1463 *flags |= RTNH_F_DEAD; 1464 break; 1465 } 1466 rcu_read_unlock(); 1467 } 1468 1469 switch (nhc->nhc_gw_family) { 1470 case AF_INET: 1471 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1472 goto nla_put_failure; 1473 break; 1474 case AF_INET6: 1475 /* if gateway family does not match nexthop family 1476 * gateway is encoded as RTA_VIA 1477 */ 1478 if (nhc->nhc_gw_family != nhc->nhc_family) { 1479 int alen = sizeof(struct in6_addr); 1480 struct nlattr *nla; 1481 struct rtvia *via; 1482 1483 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1484 if (!nla) 1485 goto nla_put_failure; 1486 1487 via = nla_data(nla); 1488 via->rtvia_family = AF_INET6; 1489 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1490 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1491 &nhc->nhc_gw.ipv6) < 0) { 1492 goto nla_put_failure; 1493 } 1494 break; 1495 } 1496 1497 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK); 1498 if (nhc->nhc_flags & RTNH_F_OFFLOAD) 1499 *flags |= RTNH_F_OFFLOAD; 1500 1501 if (!skip_oif && nhc->nhc_dev && 1502 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1503 goto nla_put_failure; 1504 1505 if (nhc->nhc_lwtstate && 1506 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate) < 0) 1507 goto nla_put_failure; 1508 1509 return 0; 1510 1511 nla_put_failure: 1512 return -EMSGSIZE; 1513 } 1514 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1515 1516 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1517 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1518 int nh_weight) 1519 { 1520 const struct net_device *dev = nhc->nhc_dev; 1521 struct rtnexthop *rtnh; 1522 unsigned int flags = 0; 1523 1524 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1525 if (!rtnh) 1526 goto nla_put_failure; 1527 1528 rtnh->rtnh_hops = nh_weight - 1; 1529 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1530 1531 if (fib_nexthop_info(skb, nhc, &flags, true) < 0) 1532 goto nla_put_failure; 1533 1534 rtnh->rtnh_flags = flags; 1535 1536 /* length of rtnetlink header + attributes */ 1537 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1538 1539 return 0; 1540 1541 nla_put_failure: 1542 return -EMSGSIZE; 1543 } 1544 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1545 #endif 1546 1547 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1548 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1549 { 1550 struct nlattr *mp; 1551 1552 mp = nla_nest_start(skb, RTA_MULTIPATH); 1553 if (!mp) 1554 goto nla_put_failure; 1555 1556 for_nexthops(fi) { 1557 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight) < 0) 1558 goto nla_put_failure; 1559 #ifdef CONFIG_IP_ROUTE_CLASSID 1560 if (nh->nh_tclassid && 1561 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1562 goto nla_put_failure; 1563 #endif 1564 } endfor_nexthops(fi); 1565 1566 nla_nest_end(skb, mp); 1567 1568 return 0; 1569 1570 nla_put_failure: 1571 return -EMSGSIZE; 1572 } 1573 #else 1574 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1575 { 1576 return 0; 1577 } 1578 #endif 1579 1580 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1581 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1582 struct fib_info *fi, unsigned int flags) 1583 { 1584 struct nlmsghdr *nlh; 1585 struct rtmsg *rtm; 1586 1587 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1588 if (!nlh) 1589 return -EMSGSIZE; 1590 1591 rtm = nlmsg_data(nlh); 1592 rtm->rtm_family = AF_INET; 1593 rtm->rtm_dst_len = dst_len; 1594 rtm->rtm_src_len = 0; 1595 rtm->rtm_tos = tos; 1596 if (tb_id < 256) 1597 rtm->rtm_table = tb_id; 1598 else 1599 rtm->rtm_table = RT_TABLE_COMPAT; 1600 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1601 goto nla_put_failure; 1602 rtm->rtm_type = type; 1603 rtm->rtm_flags = fi->fib_flags; 1604 rtm->rtm_scope = fi->fib_scope; 1605 rtm->rtm_protocol = fi->fib_protocol; 1606 1607 if (rtm->rtm_dst_len && 1608 nla_put_in_addr(skb, RTA_DST, dst)) 1609 goto nla_put_failure; 1610 if (fi->fib_priority && 1611 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1612 goto nla_put_failure; 1613 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1614 goto nla_put_failure; 1615 1616 if (fi->fib_prefsrc && 1617 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1618 goto nla_put_failure; 1619 if (fi->fib_nhs == 1) { 1620 struct fib_nh *nh = &fi->fib_nh[0]; 1621 unsigned int flags = 0; 1622 1623 if (fib_nexthop_info(skb, &nh->nh_common, &flags, false) < 0) 1624 goto nla_put_failure; 1625 1626 rtm->rtm_flags = flags; 1627 #ifdef CONFIG_IP_ROUTE_CLASSID 1628 if (nh->nh_tclassid && 1629 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1630 goto nla_put_failure; 1631 #endif 1632 } else { 1633 if (fib_add_multipath(skb, fi) < 0) 1634 goto nla_put_failure; 1635 } 1636 1637 nlmsg_end(skb, nlh); 1638 return 0; 1639 1640 nla_put_failure: 1641 nlmsg_cancel(skb, nlh); 1642 return -EMSGSIZE; 1643 } 1644 1645 /* 1646 * Update FIB if: 1647 * - local address disappeared -> we must delete all the entries 1648 * referring to it. 1649 * - device went down -> we must shutdown all nexthops going via it. 1650 */ 1651 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1652 { 1653 int ret = 0; 1654 unsigned int hash = fib_laddr_hashfn(local); 1655 struct hlist_head *head = &fib_info_laddrhash[hash]; 1656 struct net *net = dev_net(dev); 1657 int tb_id = l3mdev_fib_table(dev); 1658 struct fib_info *fi; 1659 1660 if (!fib_info_laddrhash || local == 0) 1661 return 0; 1662 1663 hlist_for_each_entry(fi, head, fib_lhash) { 1664 if (!net_eq(fi->fib_net, net) || 1665 fi->fib_tb_id != tb_id) 1666 continue; 1667 if (fi->fib_prefsrc == local) { 1668 fi->fib_flags |= RTNH_F_DEAD; 1669 ret++; 1670 } 1671 } 1672 return ret; 1673 } 1674 1675 static int call_fib_nh_notifiers(struct fib_nh *nh, 1676 enum fib_event_type event_type) 1677 { 1678 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1679 struct fib_nh_notifier_info info = { 1680 .fib_nh = nh, 1681 }; 1682 1683 switch (event_type) { 1684 case FIB_EVENT_NH_ADD: 1685 if (nh->fib_nh_flags & RTNH_F_DEAD) 1686 break; 1687 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1688 break; 1689 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1690 &info.info); 1691 case FIB_EVENT_NH_DEL: 1692 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1693 (nh->fib_nh_flags & RTNH_F_DEAD)) 1694 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1695 event_type, &info.info); 1696 default: 1697 break; 1698 } 1699 1700 return NOTIFY_DONE; 1701 } 1702 1703 /* Update the PMTU of exceptions when: 1704 * - the new MTU of the first hop becomes smaller than the PMTU 1705 * - the old MTU was the same as the PMTU, and it limited discovery of 1706 * larger MTUs on the path. With that limit raised, we can now 1707 * discover larger MTUs 1708 * A special case is locked exceptions, for which the PMTU is smaller 1709 * than the minimal accepted PMTU: 1710 * - if the new MTU is greater than the PMTU, don't make any change 1711 * - otherwise, unlock and set PMTU 1712 */ 1713 static void nh_update_mtu(struct fib_nh *nh, u32 new, u32 orig) 1714 { 1715 struct fnhe_hash_bucket *bucket; 1716 int i; 1717 1718 bucket = rcu_dereference_protected(nh->nh_exceptions, 1); 1719 if (!bucket) 1720 return; 1721 1722 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1723 struct fib_nh_exception *fnhe; 1724 1725 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1726 fnhe; 1727 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1728 if (fnhe->fnhe_mtu_locked) { 1729 if (new <= fnhe->fnhe_pmtu) { 1730 fnhe->fnhe_pmtu = new; 1731 fnhe->fnhe_mtu_locked = false; 1732 } 1733 } else if (new < fnhe->fnhe_pmtu || 1734 orig == fnhe->fnhe_pmtu) { 1735 fnhe->fnhe_pmtu = new; 1736 } 1737 } 1738 } 1739 } 1740 1741 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1742 { 1743 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1744 struct hlist_head *head = &fib_info_devhash[hash]; 1745 struct fib_nh *nh; 1746 1747 hlist_for_each_entry(nh, head, nh_hash) { 1748 if (nh->fib_nh_dev == dev) 1749 nh_update_mtu(nh, dev->mtu, orig_mtu); 1750 } 1751 } 1752 1753 /* Event force Flags Description 1754 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1755 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1756 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1757 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1758 */ 1759 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1760 { 1761 int ret = 0; 1762 int scope = RT_SCOPE_NOWHERE; 1763 struct fib_info *prev_fi = NULL; 1764 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1765 struct hlist_head *head = &fib_info_devhash[hash]; 1766 struct fib_nh *nh; 1767 1768 if (force) 1769 scope = -1; 1770 1771 hlist_for_each_entry(nh, head, nh_hash) { 1772 struct fib_info *fi = nh->nh_parent; 1773 int dead; 1774 1775 BUG_ON(!fi->fib_nhs); 1776 if (nh->fib_nh_dev != dev || fi == prev_fi) 1777 continue; 1778 prev_fi = fi; 1779 dead = 0; 1780 change_nexthops(fi) { 1781 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1782 dead++; 1783 else if (nexthop_nh->fib_nh_dev == dev && 1784 nexthop_nh->fib_nh_scope != scope) { 1785 switch (event) { 1786 case NETDEV_DOWN: 1787 case NETDEV_UNREGISTER: 1788 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 1789 /* fall through */ 1790 case NETDEV_CHANGE: 1791 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1792 break; 1793 } 1794 call_fib_nh_notifiers(nexthop_nh, 1795 FIB_EVENT_NH_DEL); 1796 dead++; 1797 } 1798 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1799 if (event == NETDEV_UNREGISTER && 1800 nexthop_nh->fib_nh_dev == dev) { 1801 dead = fi->fib_nhs; 1802 break; 1803 } 1804 #endif 1805 } endfor_nexthops(fi) 1806 if (dead == fi->fib_nhs) { 1807 switch (event) { 1808 case NETDEV_DOWN: 1809 case NETDEV_UNREGISTER: 1810 fi->fib_flags |= RTNH_F_DEAD; 1811 /* fall through */ 1812 case NETDEV_CHANGE: 1813 fi->fib_flags |= RTNH_F_LINKDOWN; 1814 break; 1815 } 1816 ret++; 1817 } 1818 1819 fib_rebalance(fi); 1820 } 1821 1822 return ret; 1823 } 1824 1825 /* Must be invoked inside of an RCU protected region. */ 1826 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1827 { 1828 struct fib_info *fi = NULL, *last_resort = NULL; 1829 struct hlist_head *fa_head = res->fa_head; 1830 struct fib_table *tb = res->table; 1831 u8 slen = 32 - res->prefixlen; 1832 int order = -1, last_idx = -1; 1833 struct fib_alias *fa, *fa1 = NULL; 1834 u32 last_prio = res->fi->fib_priority; 1835 u8 last_tos = 0; 1836 1837 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1838 struct fib_info *next_fi = fa->fa_info; 1839 1840 if (fa->fa_slen != slen) 1841 continue; 1842 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1843 continue; 1844 if (fa->tb_id != tb->tb_id) 1845 continue; 1846 if (next_fi->fib_priority > last_prio && 1847 fa->fa_tos == last_tos) { 1848 if (last_tos) 1849 continue; 1850 break; 1851 } 1852 if (next_fi->fib_flags & RTNH_F_DEAD) 1853 continue; 1854 last_tos = fa->fa_tos; 1855 last_prio = next_fi->fib_priority; 1856 1857 if (next_fi->fib_scope != res->scope || 1858 fa->fa_type != RTN_UNICAST) 1859 continue; 1860 if (!next_fi->fib_nh[0].fib_nh_gw4 || 1861 next_fi->fib_nh[0].fib_nh_scope != RT_SCOPE_LINK) 1862 continue; 1863 1864 fib_alias_accessed(fa); 1865 1866 if (!fi) { 1867 if (next_fi != res->fi) 1868 break; 1869 fa1 = fa; 1870 } else if (!fib_detect_death(fi, order, &last_resort, 1871 &last_idx, fa1->fa_default)) { 1872 fib_result_assign(res, fi); 1873 fa1->fa_default = order; 1874 goto out; 1875 } 1876 fi = next_fi; 1877 order++; 1878 } 1879 1880 if (order <= 0 || !fi) { 1881 if (fa1) 1882 fa1->fa_default = -1; 1883 goto out; 1884 } 1885 1886 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1887 fa1->fa_default)) { 1888 fib_result_assign(res, fi); 1889 fa1->fa_default = order; 1890 goto out; 1891 } 1892 1893 if (last_idx >= 0) 1894 fib_result_assign(res, last_resort); 1895 fa1->fa_default = last_idx; 1896 out: 1897 return; 1898 } 1899 1900 /* 1901 * Dead device goes up. We wake up dead nexthops. 1902 * It takes sense only on multipath routes. 1903 */ 1904 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1905 { 1906 struct fib_info *prev_fi; 1907 unsigned int hash; 1908 struct hlist_head *head; 1909 struct fib_nh *nh; 1910 int ret; 1911 1912 if (!(dev->flags & IFF_UP)) 1913 return 0; 1914 1915 if (nh_flags & RTNH_F_DEAD) { 1916 unsigned int flags = dev_get_flags(dev); 1917 1918 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1919 nh_flags |= RTNH_F_LINKDOWN; 1920 } 1921 1922 prev_fi = NULL; 1923 hash = fib_devindex_hashfn(dev->ifindex); 1924 head = &fib_info_devhash[hash]; 1925 ret = 0; 1926 1927 hlist_for_each_entry(nh, head, nh_hash) { 1928 struct fib_info *fi = nh->nh_parent; 1929 int alive; 1930 1931 BUG_ON(!fi->fib_nhs); 1932 if (nh->fib_nh_dev != dev || fi == prev_fi) 1933 continue; 1934 1935 prev_fi = fi; 1936 alive = 0; 1937 change_nexthops(fi) { 1938 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 1939 alive++; 1940 continue; 1941 } 1942 if (!nexthop_nh->fib_nh_dev || 1943 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 1944 continue; 1945 if (nexthop_nh->fib_nh_dev != dev || 1946 !__in_dev_get_rtnl(dev)) 1947 continue; 1948 alive++; 1949 nexthop_nh->fib_nh_flags &= ~nh_flags; 1950 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 1951 } endfor_nexthops(fi) 1952 1953 if (alive > 0) { 1954 fi->fib_flags &= ~nh_flags; 1955 ret++; 1956 } 1957 1958 fib_rebalance(fi); 1959 } 1960 1961 return ret; 1962 } 1963 1964 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1965 static bool fib_good_nh(const struct fib_nh *nh) 1966 { 1967 int state = NUD_REACHABLE; 1968 1969 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 1970 struct neighbour *n; 1971 1972 rcu_read_lock_bh(); 1973 1974 if (likely(nh->fib_nh_gw_family == AF_INET)) 1975 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 1976 (__force u32)nh->fib_nh_gw4); 1977 else if (nh->fib_nh_gw_family == AF_INET6) 1978 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 1979 &nh->fib_nh_gw6); 1980 else 1981 n = NULL; 1982 if (n) 1983 state = n->nud_state; 1984 1985 rcu_read_unlock_bh(); 1986 } 1987 1988 return !!(state & NUD_VALID); 1989 } 1990 1991 void fib_select_multipath(struct fib_result *res, int hash) 1992 { 1993 struct fib_info *fi = res->fi; 1994 struct net *net = fi->fib_net; 1995 bool first = false; 1996 1997 change_nexthops(fi) { 1998 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 1999 if (!fib_good_nh(nexthop_nh)) 2000 continue; 2001 if (!first) { 2002 res->nh_sel = nhsel; 2003 res->nhc = &nexthop_nh->nh_common; 2004 first = true; 2005 } 2006 } 2007 2008 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2009 continue; 2010 2011 res->nh_sel = nhsel; 2012 res->nhc = &nexthop_nh->nh_common; 2013 return; 2014 } endfor_nexthops(fi); 2015 } 2016 #endif 2017 2018 void fib_select_path(struct net *net, struct fib_result *res, 2019 struct flowi4 *fl4, const struct sk_buff *skb) 2020 { 2021 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 2022 goto check_saddr; 2023 2024 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2025 if (res->fi->fib_nhs > 1) { 2026 int h = fib_multipath_hash(net, fl4, skb, NULL); 2027 2028 fib_select_multipath(res, h); 2029 } 2030 else 2031 #endif 2032 if (!res->prefixlen && 2033 res->table->tb_num_default > 1 && 2034 res->type == RTN_UNICAST) 2035 fib_select_default(fl4, res); 2036 2037 check_saddr: 2038 if (!fl4->saddr) 2039 fl4->saddr = fib_result_prefsrc(net, res); 2040 } 2041