1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * IPv4 Forwarding Information Base: semantics. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 */ 11 12 #include <linux/uaccess.h> 13 #include <linux/bitops.h> 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/jiffies.h> 17 #include <linux/mm.h> 18 #include <linux/string.h> 19 #include <linux/socket.h> 20 #include <linux/sockios.h> 21 #include <linux/errno.h> 22 #include <linux/in.h> 23 #include <linux/inet.h> 24 #include <linux/inetdevice.h> 25 #include <linux/netdevice.h> 26 #include <linux/if_arp.h> 27 #include <linux/proc_fs.h> 28 #include <linux/skbuff.h> 29 #include <linux/init.h> 30 #include <linux/slab.h> 31 #include <linux/netlink.h> 32 #include <linux/hash.h> 33 #include <linux/nospec.h> 34 35 #include <net/arp.h> 36 #include <net/inet_dscp.h> 37 #include <net/ip.h> 38 #include <net/protocol.h> 39 #include <net/route.h> 40 #include <net/tcp.h> 41 #include <net/sock.h> 42 #include <net/ip_fib.h> 43 #include <net/ip6_fib.h> 44 #include <net/nexthop.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 /* for_nexthops and change_nexthops only used when nexthop object 54 * is not set in a fib_info. The logic within can reference fib_nh. 55 */ 56 #ifdef CONFIG_IP_ROUTE_MULTIPATH 57 58 #define for_nexthops(fi) { \ 59 int nhsel; const struct fib_nh *nh; \ 60 for (nhsel = 0, nh = (fi)->fib_nh; \ 61 nhsel < fib_info_num_path((fi)); \ 62 nh++, nhsel++) 63 64 #define change_nexthops(fi) { \ 65 int nhsel; struct fib_nh *nexthop_nh; \ 66 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 67 nhsel < fib_info_num_path((fi)); \ 68 nexthop_nh++, nhsel++) 69 70 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 71 72 /* Hope, that gcc will optimize it to get rid of dummy loop */ 73 74 #define for_nexthops(fi) { \ 75 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 76 for (nhsel = 0; nhsel < 1; nhsel++) 77 78 #define change_nexthops(fi) { \ 79 int nhsel; \ 80 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 81 for (nhsel = 0; nhsel < 1; nhsel++) 82 83 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 84 85 #define endfor_nexthops(fi) } 86 87 88 const struct fib_prop fib_props[RTN_MAX + 1] = { 89 [RTN_UNSPEC] = { 90 .error = 0, 91 .scope = RT_SCOPE_NOWHERE, 92 }, 93 [RTN_UNICAST] = { 94 .error = 0, 95 .scope = RT_SCOPE_UNIVERSE, 96 }, 97 [RTN_LOCAL] = { 98 .error = 0, 99 .scope = RT_SCOPE_HOST, 100 }, 101 [RTN_BROADCAST] = { 102 .error = 0, 103 .scope = RT_SCOPE_LINK, 104 }, 105 [RTN_ANYCAST] = { 106 .error = 0, 107 .scope = RT_SCOPE_LINK, 108 }, 109 [RTN_MULTICAST] = { 110 .error = 0, 111 .scope = RT_SCOPE_UNIVERSE, 112 }, 113 [RTN_BLACKHOLE] = { 114 .error = -EINVAL, 115 .scope = RT_SCOPE_UNIVERSE, 116 }, 117 [RTN_UNREACHABLE] = { 118 .error = -EHOSTUNREACH, 119 .scope = RT_SCOPE_UNIVERSE, 120 }, 121 [RTN_PROHIBIT] = { 122 .error = -EACCES, 123 .scope = RT_SCOPE_UNIVERSE, 124 }, 125 [RTN_THROW] = { 126 .error = -EAGAIN, 127 .scope = RT_SCOPE_UNIVERSE, 128 }, 129 [RTN_NAT] = { 130 .error = -EINVAL, 131 .scope = RT_SCOPE_NOWHERE, 132 }, 133 [RTN_XRESOLVE] = { 134 .error = -EINVAL, 135 .scope = RT_SCOPE_NOWHERE, 136 }, 137 }; 138 139 static void rt_fibinfo_free(struct rtable __rcu **rtp) 140 { 141 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 142 143 if (!rt) 144 return; 145 146 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 147 * because we waited an RCU grace period before calling 148 * free_fib_info_rcu() 149 */ 150 151 dst_dev_put(&rt->dst); 152 dst_release_immediate(&rt->dst); 153 } 154 155 static void free_nh_exceptions(struct fib_nh_common *nhc) 156 { 157 struct fnhe_hash_bucket *hash; 158 int i; 159 160 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); 161 if (!hash) 162 return; 163 for (i = 0; i < FNHE_HASH_SIZE; i++) { 164 struct fib_nh_exception *fnhe; 165 166 fnhe = rcu_dereference_protected(hash[i].chain, 1); 167 while (fnhe) { 168 struct fib_nh_exception *next; 169 170 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 171 172 rt_fibinfo_free(&fnhe->fnhe_rth_input); 173 rt_fibinfo_free(&fnhe->fnhe_rth_output); 174 175 kfree(fnhe); 176 177 fnhe = next; 178 } 179 } 180 kfree(hash); 181 } 182 183 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 184 { 185 int cpu; 186 187 if (!rtp) 188 return; 189 190 for_each_possible_cpu(cpu) { 191 struct rtable *rt; 192 193 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 194 if (rt) { 195 dst_dev_put(&rt->dst); 196 dst_release_immediate(&rt->dst); 197 } 198 } 199 free_percpu(rtp); 200 } 201 202 void fib_nh_common_release(struct fib_nh_common *nhc) 203 { 204 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker); 205 lwtstate_put(nhc->nhc_lwtstate); 206 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 207 rt_fibinfo_free(&nhc->nhc_rth_input); 208 free_nh_exceptions(nhc); 209 } 210 EXPORT_SYMBOL_GPL(fib_nh_common_release); 211 212 void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 213 { 214 #ifdef CONFIG_IP_ROUTE_CLASSID 215 if (fib_nh->nh_tclassid) 216 atomic_dec(&net->ipv4.fib_num_tclassid_users); 217 #endif 218 fib_nh_common_release(&fib_nh->nh_common); 219 } 220 221 /* Release a nexthop info record */ 222 static void free_fib_info_rcu(struct rcu_head *head) 223 { 224 struct fib_info *fi = container_of(head, struct fib_info, rcu); 225 226 if (fi->nh) { 227 nexthop_put(fi->nh); 228 } else { 229 change_nexthops(fi) { 230 fib_nh_release(fi->fib_net, nexthop_nh); 231 } endfor_nexthops(fi); 232 } 233 234 ip_fib_metrics_put(fi->fib_metrics); 235 236 kfree(fi); 237 } 238 239 void free_fib_info(struct fib_info *fi) 240 { 241 if (fi->fib_dead == 0) { 242 pr_warn("Freeing alive fib_info %p\n", fi); 243 return; 244 } 245 246 call_rcu_hurry(&fi->rcu, free_fib_info_rcu); 247 } 248 EXPORT_SYMBOL_GPL(free_fib_info); 249 250 void fib_release_info(struct fib_info *fi) 251 { 252 ASSERT_RTNL(); 253 if (fi && refcount_dec_and_test(&fi->fib_treeref)) { 254 hlist_del(&fi->fib_hash); 255 fi->fib_net->ipv4.fib_info_cnt--; 256 257 if (fi->fib_prefsrc) 258 hlist_del(&fi->fib_lhash); 259 if (fi->nh) { 260 list_del(&fi->nh_list); 261 } else { 262 change_nexthops(fi) { 263 if (!nexthop_nh->fib_nh_dev) 264 continue; 265 hlist_del_rcu(&nexthop_nh->nh_hash); 266 } endfor_nexthops(fi) 267 } 268 /* Paired with READ_ONCE() from fib_table_lookup() */ 269 WRITE_ONCE(fi->fib_dead, 1); 270 fib_info_put(fi); 271 } 272 } 273 274 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 275 { 276 const struct fib_nh *onh; 277 278 if (fi->nh || ofi->nh) 279 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 280 281 if (ofi->fib_nhs == 0) 282 return 0; 283 284 for_nexthops(fi) { 285 onh = fib_info_nh(ofi, nhsel); 286 287 if (nh->fib_nh_oif != onh->fib_nh_oif || 288 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 289 nh->fib_nh_scope != onh->fib_nh_scope || 290 #ifdef CONFIG_IP_ROUTE_MULTIPATH 291 nh->fib_nh_weight != onh->fib_nh_weight || 292 #endif 293 #ifdef CONFIG_IP_ROUTE_CLASSID 294 nh->nh_tclassid != onh->nh_tclassid || 295 #endif 296 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 297 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 298 return -1; 299 300 if (nh->fib_nh_gw_family == AF_INET && 301 nh->fib_nh_gw4 != onh->fib_nh_gw4) 302 return -1; 303 304 if (nh->fib_nh_gw_family == AF_INET6 && 305 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 306 return -1; 307 } endfor_nexthops(fi); 308 return 0; 309 } 310 311 static struct hlist_head *fib_nh_head(struct net_device *dev) 312 { 313 return &dev->fib_nh_head; 314 } 315 316 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 317 u32 prefsrc, u32 priority) 318 { 319 unsigned int val = init_val; 320 321 val ^= (protocol << 8) | scope; 322 val ^= prefsrc; 323 val ^= priority; 324 325 return val; 326 } 327 328 static unsigned int fib_info_hashfn_result(const struct net *net, 329 unsigned int val) 330 { 331 return hash_32(val ^ net_hash_mix(net), net->ipv4.fib_info_hash_bits); 332 } 333 334 static struct hlist_head *fib_info_hash_bucket(struct fib_info *fi) 335 { 336 struct net *net = fi->fib_net; 337 unsigned int val; 338 339 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 340 fi->fib_scope, (__force u32)fi->fib_prefsrc, 341 fi->fib_priority); 342 343 if (fi->nh) { 344 val ^= fi->nh->id; 345 } else { 346 for_nexthops(fi) { 347 val ^= nh->fib_nh_oif; 348 } endfor_nexthops(fi) 349 } 350 351 return &net->ipv4.fib_info_hash[fib_info_hashfn_result(net, val)]; 352 } 353 354 static struct hlist_head *fib_info_laddrhash_bucket(const struct net *net, 355 __be32 val) 356 { 357 unsigned int hash_bits = net->ipv4.fib_info_hash_bits; 358 u32 slot; 359 360 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, hash_bits); 361 362 return &net->ipv4.fib_info_hash[(1 << hash_bits) + slot]; 363 } 364 365 static struct hlist_head *fib_info_hash_alloc(unsigned int hash_bits) 366 { 367 /* The second half is used for prefsrc */ 368 return kvcalloc((1 << hash_bits) * 2, sizeof(struct hlist_head), 369 GFP_KERNEL); 370 } 371 372 static void fib_info_hash_free(struct hlist_head *head) 373 { 374 kvfree(head); 375 } 376 377 static void fib_info_hash_grow(struct net *net) 378 { 379 unsigned int old_size = 1 << net->ipv4.fib_info_hash_bits; 380 struct hlist_head *new_info_hash, *old_info_hash; 381 unsigned int i; 382 383 if (net->ipv4.fib_info_cnt < old_size) 384 return; 385 386 new_info_hash = fib_info_hash_alloc(net->ipv4.fib_info_hash_bits + 1); 387 if (!new_info_hash) 388 return; 389 390 old_info_hash = net->ipv4.fib_info_hash; 391 net->ipv4.fib_info_hash = new_info_hash; 392 net->ipv4.fib_info_hash_bits += 1; 393 394 for (i = 0; i < old_size; i++) { 395 struct hlist_head *head = &old_info_hash[i]; 396 struct hlist_node *n; 397 struct fib_info *fi; 398 399 hlist_for_each_entry_safe(fi, n, head, fib_hash) 400 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi)); 401 } 402 403 for (i = 0; i < old_size; i++) { 404 struct hlist_head *lhead = &old_info_hash[old_size + i]; 405 struct hlist_node *n; 406 struct fib_info *fi; 407 408 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) 409 hlist_add_head(&fi->fib_lhash, 410 fib_info_laddrhash_bucket(fi->fib_net, 411 fi->fib_prefsrc)); 412 } 413 414 fib_info_hash_free(old_info_hash); 415 } 416 417 /* no metrics, only nexthop id */ 418 static struct fib_info *fib_find_info_nh(struct net *net, 419 const struct fib_config *cfg) 420 { 421 struct hlist_head *head; 422 struct fib_info *fi; 423 unsigned int hash; 424 425 hash = fib_info_hashfn_1(cfg->fc_nh_id, 426 cfg->fc_protocol, cfg->fc_scope, 427 (__force u32)cfg->fc_prefsrc, 428 cfg->fc_priority); 429 hash = fib_info_hashfn_result(net, hash); 430 head = &net->ipv4.fib_info_hash[hash]; 431 432 hlist_for_each_entry(fi, head, fib_hash) { 433 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 434 continue; 435 436 if (cfg->fc_protocol == fi->fib_protocol && 437 cfg->fc_scope == fi->fib_scope && 438 cfg->fc_prefsrc == fi->fib_prefsrc && 439 cfg->fc_priority == fi->fib_priority && 440 cfg->fc_type == fi->fib_type && 441 cfg->fc_table == fi->fib_tb_id && 442 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 443 return fi; 444 } 445 446 return NULL; 447 } 448 449 static struct fib_info *fib_find_info(struct fib_info *nfi) 450 { 451 struct hlist_head *head = fib_info_hash_bucket(nfi); 452 struct fib_info *fi; 453 454 hlist_for_each_entry(fi, head, fib_hash) { 455 if (fi->fib_nhs != nfi->fib_nhs) 456 continue; 457 458 if (nfi->fib_protocol == fi->fib_protocol && 459 nfi->fib_scope == fi->fib_scope && 460 nfi->fib_prefsrc == fi->fib_prefsrc && 461 nfi->fib_priority == fi->fib_priority && 462 nfi->fib_type == fi->fib_type && 463 nfi->fib_tb_id == fi->fib_tb_id && 464 memcmp(nfi->fib_metrics, fi->fib_metrics, 465 sizeof(u32) * RTAX_MAX) == 0 && 466 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 467 nh_comp(fi, nfi) == 0) 468 return fi; 469 } 470 471 return NULL; 472 } 473 474 /* Check, that the gateway is already configured. 475 * Used only by redirect accept routine, under rcu_read_lock(); 476 */ 477 int ip_fib_check_default(__be32 gw, struct net_device *dev) 478 { 479 struct hlist_head *head; 480 struct fib_nh *nh; 481 482 head = fib_nh_head(dev); 483 484 hlist_for_each_entry_rcu(nh, head, nh_hash) { 485 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); 486 if (nh->fib_nh_gw4 == gw && 487 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 488 return 0; 489 } 490 } 491 492 return -1; 493 } 494 495 size_t fib_nlmsg_size(struct fib_info *fi) 496 { 497 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 498 + nla_total_size(4) /* RTA_TABLE */ 499 + nla_total_size(4) /* RTA_DST */ 500 + nla_total_size(4) /* RTA_PRIORITY */ 501 + nla_total_size(4) /* RTA_PREFSRC */ 502 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 503 unsigned int nhs = fib_info_num_path(fi); 504 505 /* space for nested metrics */ 506 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 507 508 if (fi->nh) 509 payload += nla_total_size(4); /* RTA_NH_ID */ 510 511 if (nhs) { 512 size_t nh_encapsize = 0; 513 /* Also handles the special case nhs == 1 */ 514 515 /* each nexthop is packed in an attribute */ 516 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 517 unsigned int i; 518 519 /* may contain flow and gateway attribute */ 520 nhsize += 2 * nla_total_size(4); 521 522 /* grab encap info */ 523 for (i = 0; i < fib_info_num_path(fi); i++) { 524 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 525 526 if (nhc->nhc_lwtstate) { 527 /* RTA_ENCAP_TYPE */ 528 nh_encapsize += lwtunnel_get_encap_size( 529 nhc->nhc_lwtstate); 530 /* RTA_ENCAP */ 531 nh_encapsize += nla_total_size(2); 532 } 533 } 534 535 /* all nexthops are packed in a nested attribute */ 536 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 537 538 } 539 540 return payload; 541 } 542 543 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 544 int dst_len, u32 tb_id, const struct nl_info *info, 545 unsigned int nlm_flags) 546 { 547 struct fib_rt_info fri; 548 struct sk_buff *skb; 549 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 550 int err = -ENOBUFS; 551 552 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 553 if (!skb) 554 goto errout; 555 556 fri.fi = fa->fa_info; 557 fri.tb_id = tb_id; 558 fri.dst = key; 559 fri.dst_len = dst_len; 560 fri.dscp = fa->fa_dscp; 561 fri.type = fa->fa_type; 562 fri.offload = READ_ONCE(fa->offload); 563 fri.trap = READ_ONCE(fa->trap); 564 fri.offload_failed = READ_ONCE(fa->offload_failed); 565 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 566 if (err < 0) { 567 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 568 WARN_ON(err == -EMSGSIZE); 569 kfree_skb(skb); 570 goto errout; 571 } 572 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 573 info->nlh, GFP_KERNEL); 574 return; 575 errout: 576 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 577 } 578 579 static int fib_detect_death(struct fib_info *fi, int order, 580 struct fib_info **last_resort, int *last_idx, 581 int dflt) 582 { 583 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 584 struct neighbour *n; 585 int state = NUD_NONE; 586 587 if (likely(nhc->nhc_gw_family == AF_INET)) 588 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 589 else if (nhc->nhc_gw_family == AF_INET6) 590 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 591 nhc->nhc_dev); 592 else 593 n = NULL; 594 595 if (n) { 596 state = READ_ONCE(n->nud_state); 597 neigh_release(n); 598 } else { 599 return 0; 600 } 601 if (state == NUD_REACHABLE) 602 return 0; 603 if ((state & NUD_VALID) && order != dflt) 604 return 0; 605 if ((state & NUD_VALID) || 606 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 607 *last_resort = fi; 608 *last_idx = order; 609 } 610 return 1; 611 } 612 613 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 614 struct nlattr *encap, u16 encap_type, 615 void *cfg, gfp_t gfp_flags, 616 struct netlink_ext_ack *extack) 617 { 618 int err; 619 620 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 621 gfp_flags); 622 if (!nhc->nhc_pcpu_rth_output) 623 return -ENOMEM; 624 625 if (encap) { 626 struct lwtunnel_state *lwtstate; 627 628 err = lwtunnel_build_state(net, encap_type, encap, 629 nhc->nhc_family, cfg, &lwtstate, 630 extack); 631 if (err) 632 goto lwt_failure; 633 634 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 635 } 636 637 return 0; 638 639 lwt_failure: 640 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 641 nhc->nhc_pcpu_rth_output = NULL; 642 return err; 643 } 644 EXPORT_SYMBOL_GPL(fib_nh_common_init); 645 646 int fib_nh_init(struct net *net, struct fib_nh *nh, 647 struct fib_config *cfg, int nh_weight, 648 struct netlink_ext_ack *extack) 649 { 650 int err; 651 652 nh->fib_nh_family = AF_INET; 653 654 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 655 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 656 if (err) 657 return err; 658 659 nh->fib_nh_oif = cfg->fc_oif; 660 nh->fib_nh_gw_family = cfg->fc_gw_family; 661 if (cfg->fc_gw_family == AF_INET) 662 nh->fib_nh_gw4 = cfg->fc_gw4; 663 else if (cfg->fc_gw_family == AF_INET6) 664 nh->fib_nh_gw6 = cfg->fc_gw6; 665 666 nh->fib_nh_flags = cfg->fc_flags; 667 668 #ifdef CONFIG_IP_ROUTE_CLASSID 669 nh->nh_tclassid = cfg->fc_flow; 670 if (nh->nh_tclassid) 671 atomic_inc(&net->ipv4.fib_num_tclassid_users); 672 #endif 673 #ifdef CONFIG_IP_ROUTE_MULTIPATH 674 nh->fib_nh_weight = nh_weight; 675 #endif 676 return 0; 677 } 678 679 #ifdef CONFIG_IP_ROUTE_MULTIPATH 680 681 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 682 struct netlink_ext_ack *extack) 683 { 684 int nhs = 0; 685 686 while (rtnh_ok(rtnh, remaining)) { 687 nhs++; 688 rtnh = rtnh_next(rtnh, &remaining); 689 } 690 691 /* leftover implies invalid nexthop configuration, discard it */ 692 if (remaining > 0) { 693 NL_SET_ERR_MSG(extack, 694 "Invalid nexthop configuration - extra data after nexthops"); 695 nhs = 0; 696 } 697 698 return nhs; 699 } 700 701 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 702 struct netlink_ext_ack *extack) 703 { 704 if (nla_len(nla) < sizeof(*gw)) { 705 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 706 return -EINVAL; 707 } 708 709 *gw = nla_get_in_addr(nla); 710 711 return 0; 712 } 713 714 /* only called when fib_nh is integrated into fib_info */ 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 struct net *net = fi->fib_net; 720 struct fib_config fib_cfg; 721 struct fib_nh *nh; 722 int ret; 723 724 change_nexthops(fi) { 725 int attrlen; 726 727 memset(&fib_cfg, 0, sizeof(fib_cfg)); 728 729 if (!rtnh_ok(rtnh, remaining)) { 730 NL_SET_ERR_MSG(extack, 731 "Invalid nexthop configuration - extra data after nexthop"); 732 return -EINVAL; 733 } 734 735 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 736 NL_SET_ERR_MSG(extack, 737 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 738 return -EINVAL; 739 } 740 741 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 742 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 743 744 attrlen = rtnh_attrlen(rtnh); 745 if (attrlen > 0) { 746 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 747 748 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 749 nlav = nla_find(attrs, attrlen, RTA_VIA); 750 if (nla && nlav) { 751 NL_SET_ERR_MSG(extack, 752 "Nexthop configuration can not contain both GATEWAY and VIA"); 753 return -EINVAL; 754 } 755 if (nla) { 756 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 757 extack); 758 if (ret) 759 goto errout; 760 761 if (fib_cfg.fc_gw4) 762 fib_cfg.fc_gw_family = AF_INET; 763 } else if (nlav) { 764 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 765 if (ret) 766 goto errout; 767 } 768 769 nla = nla_find(attrs, attrlen, RTA_FLOW); 770 if (nla) { 771 if (nla_len(nla) < sizeof(u32)) { 772 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 773 return -EINVAL; 774 } 775 fib_cfg.fc_flow = nla_get_u32(nla); 776 } 777 778 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 779 /* RTA_ENCAP_TYPE length checked in 780 * lwtunnel_valid_encap_type_attr 781 */ 782 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 783 if (nla) 784 fib_cfg.fc_encap_type = nla_get_u16(nla); 785 } 786 787 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 788 rtnh->rtnh_hops + 1, extack); 789 if (ret) 790 goto errout; 791 792 rtnh = rtnh_next(rtnh, &remaining); 793 } endfor_nexthops(fi); 794 795 ret = -EINVAL; 796 nh = fib_info_nh(fi, 0); 797 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 798 NL_SET_ERR_MSG(extack, 799 "Nexthop device index does not match RTA_OIF"); 800 goto errout; 801 } 802 if (cfg->fc_gw_family) { 803 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 804 (cfg->fc_gw_family == AF_INET && 805 nh->fib_nh_gw4 != cfg->fc_gw4) || 806 (cfg->fc_gw_family == AF_INET6 && 807 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 808 NL_SET_ERR_MSG(extack, 809 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 810 goto errout; 811 } 812 } 813 #ifdef CONFIG_IP_ROUTE_CLASSID 814 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 815 NL_SET_ERR_MSG(extack, 816 "Nexthop class id does not match RTA_FLOW"); 817 goto errout; 818 } 819 #endif 820 ret = 0; 821 errout: 822 return ret; 823 } 824 825 /* only called when fib_nh is integrated into fib_info */ 826 static void fib_rebalance(struct fib_info *fi) 827 { 828 int total; 829 int w; 830 831 if (fib_info_num_path(fi) < 2) 832 return; 833 834 total = 0; 835 for_nexthops(fi) { 836 if (nh->fib_nh_flags & RTNH_F_DEAD) 837 continue; 838 839 if (ip_ignore_linkdown(nh->fib_nh_dev) && 840 nh->fib_nh_flags & RTNH_F_LINKDOWN) 841 continue; 842 843 total += nh->fib_nh_weight; 844 } endfor_nexthops(fi); 845 846 w = 0; 847 change_nexthops(fi) { 848 int upper_bound; 849 850 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 851 upper_bound = -1; 852 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 853 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 854 upper_bound = -1; 855 } else { 856 w += nexthop_nh->fib_nh_weight; 857 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 858 total) - 1; 859 } 860 861 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 862 } endfor_nexthops(fi); 863 } 864 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 865 866 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 867 int remaining, struct fib_config *cfg, 868 struct netlink_ext_ack *extack) 869 { 870 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 871 872 return -EINVAL; 873 } 874 875 #define fib_rebalance(fi) do { } while (0) 876 877 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 878 879 static int fib_encap_match(struct net *net, u16 encap_type, 880 struct nlattr *encap, 881 const struct fib_nh *nh, 882 const struct fib_config *cfg, 883 struct netlink_ext_ack *extack) 884 { 885 struct lwtunnel_state *lwtstate; 886 int ret, result = 0; 887 888 if (encap_type == LWTUNNEL_ENCAP_NONE) 889 return 0; 890 891 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 892 cfg, &lwtstate, extack); 893 if (!ret) { 894 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 895 lwtstate_free(lwtstate); 896 } 897 898 return result; 899 } 900 901 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 902 struct netlink_ext_ack *extack) 903 { 904 #ifdef CONFIG_IP_ROUTE_MULTIPATH 905 struct rtnexthop *rtnh; 906 int remaining; 907 #endif 908 909 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 910 return 1; 911 912 if (cfg->fc_nh_id) { 913 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 914 return 0; 915 return 1; 916 } 917 918 if (fi->nh) { 919 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 920 return 1; 921 return 0; 922 } 923 924 if (cfg->fc_oif || cfg->fc_gw_family) { 925 struct fib_nh *nh; 926 927 nh = fib_info_nh(fi, 0); 928 if (cfg->fc_encap) { 929 if (fib_encap_match(net, cfg->fc_encap_type, 930 cfg->fc_encap, nh, cfg, extack)) 931 return 1; 932 } 933 #ifdef CONFIG_IP_ROUTE_CLASSID 934 if (cfg->fc_flow && 935 cfg->fc_flow != nh->nh_tclassid) 936 return 1; 937 #endif 938 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 939 (cfg->fc_gw_family && 940 cfg->fc_gw_family != nh->fib_nh_gw_family)) 941 return 1; 942 943 if (cfg->fc_gw_family == AF_INET && 944 cfg->fc_gw4 != nh->fib_nh_gw4) 945 return 1; 946 947 if (cfg->fc_gw_family == AF_INET6 && 948 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 949 return 1; 950 951 return 0; 952 } 953 954 #ifdef CONFIG_IP_ROUTE_MULTIPATH 955 if (!cfg->fc_mp) 956 return 0; 957 958 rtnh = cfg->fc_mp; 959 remaining = cfg->fc_mp_len; 960 961 for_nexthops(fi) { 962 int attrlen; 963 964 if (!rtnh_ok(rtnh, remaining)) 965 return -EINVAL; 966 967 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 968 return 1; 969 970 attrlen = rtnh_attrlen(rtnh); 971 if (attrlen > 0) { 972 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 973 int err; 974 975 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 976 nlav = nla_find(attrs, attrlen, RTA_VIA); 977 if (nla && nlav) { 978 NL_SET_ERR_MSG(extack, 979 "Nexthop configuration can not contain both GATEWAY and VIA"); 980 return -EINVAL; 981 } 982 983 if (nla) { 984 __be32 gw; 985 986 err = fib_gw_from_attr(&gw, nla, extack); 987 if (err) 988 return err; 989 990 if (nh->fib_nh_gw_family != AF_INET || 991 gw != nh->fib_nh_gw4) 992 return 1; 993 } else if (nlav) { 994 struct fib_config cfg2; 995 996 err = fib_gw_from_via(&cfg2, nlav, extack); 997 if (err) 998 return err; 999 1000 switch (nh->fib_nh_gw_family) { 1001 case AF_INET: 1002 if (cfg2.fc_gw_family != AF_INET || 1003 cfg2.fc_gw4 != nh->fib_nh_gw4) 1004 return 1; 1005 break; 1006 case AF_INET6: 1007 if (cfg2.fc_gw_family != AF_INET6 || 1008 ipv6_addr_cmp(&cfg2.fc_gw6, 1009 &nh->fib_nh_gw6)) 1010 return 1; 1011 break; 1012 } 1013 } 1014 1015 #ifdef CONFIG_IP_ROUTE_CLASSID 1016 nla = nla_find(attrs, attrlen, RTA_FLOW); 1017 if (nla) { 1018 if (nla_len(nla) < sizeof(u32)) { 1019 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 1020 return -EINVAL; 1021 } 1022 if (nla_get_u32(nla) != nh->nh_tclassid) 1023 return 1; 1024 } 1025 #endif 1026 } 1027 1028 rtnh = rtnh_next(rtnh, &remaining); 1029 } endfor_nexthops(fi); 1030 #endif 1031 return 0; 1032 } 1033 1034 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1035 { 1036 struct nlattr *nla; 1037 int remaining; 1038 1039 if (!cfg->fc_mx) 1040 return true; 1041 1042 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1043 int type = nla_type(nla); 1044 u32 fi_val, val; 1045 1046 if (!type) 1047 continue; 1048 if (type > RTAX_MAX) 1049 return false; 1050 1051 type = array_index_nospec(type, RTAX_MAX + 1); 1052 if (type == RTAX_CC_ALGO) { 1053 char tmp[TCP_CA_NAME_MAX]; 1054 bool ecn_ca = false; 1055 1056 nla_strscpy(tmp, nla, sizeof(tmp)); 1057 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 1058 } else { 1059 if (nla_len(nla) != sizeof(u32)) 1060 return false; 1061 val = nla_get_u32(nla); 1062 } 1063 1064 fi_val = fi->fib_metrics->metrics[type - 1]; 1065 if (type == RTAX_FEATURES) 1066 fi_val &= ~DST_FEATURE_ECN_CA; 1067 1068 if (fi_val != val) 1069 return false; 1070 } 1071 1072 return true; 1073 } 1074 1075 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1076 u32 table, struct netlink_ext_ack *extack) 1077 { 1078 struct fib6_config cfg = { 1079 .fc_table = table, 1080 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1081 .fc_ifindex = nh->fib_nh_oif, 1082 .fc_gateway = nh->fib_nh_gw6, 1083 }; 1084 struct fib6_nh fib6_nh = {}; 1085 int err; 1086 1087 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1088 if (!err) { 1089 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1090 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1091 GFP_KERNEL); 1092 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1093 nh->fib_nh_scope = RT_SCOPE_LINK; 1094 1095 ipv6_stub->fib6_nh_release(&fib6_nh); 1096 } 1097 1098 return err; 1099 } 1100 1101 /* 1102 * Picture 1103 * ------- 1104 * 1105 * Semantics of nexthop is very messy by historical reasons. 1106 * We have to take into account, that: 1107 * a) gateway can be actually local interface address, 1108 * so that gatewayed route is direct. 1109 * b) gateway must be on-link address, possibly 1110 * described not by an ifaddr, but also by a direct route. 1111 * c) If both gateway and interface are specified, they should not 1112 * contradict. 1113 * d) If we use tunnel routes, gateway could be not on-link. 1114 * 1115 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1116 * results in pretty ugly and hairy code with obscure logic. 1117 * 1118 * I chose to generalized it instead, so that the size 1119 * of code does not increase practically, but it becomes 1120 * much more general. 1121 * Every prefix is assigned a "scope" value: "host" is local address, 1122 * "link" is direct route, 1123 * [ ... "site" ... "interior" ... ] 1124 * and "universe" is true gateway route with global meaning. 1125 * 1126 * Every prefix refers to a set of "nexthop"s (gw, oif), 1127 * where gw must have narrower scope. This recursion stops 1128 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1129 * which means that gw is forced to be on link. 1130 * 1131 * Code is still hairy, but now it is apparently logically 1132 * consistent and very flexible. F.e. as by-product it allows 1133 * to co-exists in peace independent exterior and interior 1134 * routing processes. 1135 * 1136 * Normally it looks as following. 1137 * 1138 * {universe prefix} -> (gw, oif) [scope link] 1139 * | 1140 * |-> {link prefix} -> (gw, oif) [scope local] 1141 * | 1142 * |-> {local prefix} (terminal node) 1143 */ 1144 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1145 u8 scope, struct netlink_ext_ack *extack) 1146 { 1147 struct net_device *dev; 1148 struct fib_result res; 1149 int err = 0; 1150 1151 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1152 unsigned int addr_type; 1153 1154 if (scope >= RT_SCOPE_LINK) { 1155 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1156 return -EINVAL; 1157 } 1158 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1159 if (!dev) { 1160 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1161 return -ENODEV; 1162 } 1163 if (!(dev->flags & IFF_UP)) { 1164 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1165 return -ENETDOWN; 1166 } 1167 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1168 if (addr_type != RTN_UNICAST) { 1169 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1170 return -EINVAL; 1171 } 1172 if (!netif_carrier_ok(dev)) 1173 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1174 nh->fib_nh_dev = dev; 1175 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1176 nh->fib_nh_scope = RT_SCOPE_LINK; 1177 return 0; 1178 } 1179 rcu_read_lock(); 1180 { 1181 struct fib_table *tbl = NULL; 1182 struct flowi4 fl4 = { 1183 .daddr = nh->fib_nh_gw4, 1184 .flowi4_scope = scope + 1, 1185 .flowi4_oif = nh->fib_nh_oif, 1186 .flowi4_iif = LOOPBACK_IFINDEX, 1187 }; 1188 1189 /* It is not necessary, but requires a bit of thinking */ 1190 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1191 fl4.flowi4_scope = RT_SCOPE_LINK; 1192 1193 if (table && table != RT_TABLE_MAIN) 1194 tbl = fib_get_table(net, table); 1195 1196 if (tbl) 1197 err = fib_table_lookup(tbl, &fl4, &res, 1198 FIB_LOOKUP_IGNORE_LINKSTATE | 1199 FIB_LOOKUP_NOREF); 1200 1201 /* on error or if no table given do full lookup. This 1202 * is needed for example when nexthops are in the local 1203 * table rather than the given table 1204 */ 1205 if (!tbl || err) { 1206 err = fib_lookup(net, &fl4, &res, 1207 FIB_LOOKUP_IGNORE_LINKSTATE); 1208 } 1209 1210 if (err) { 1211 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1212 goto out; 1213 } 1214 } 1215 1216 err = -EINVAL; 1217 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1218 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1219 goto out; 1220 } 1221 nh->fib_nh_scope = res.scope; 1222 nh->fib_nh_oif = FIB_RES_OIF(res); 1223 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1224 if (!dev) { 1225 NL_SET_ERR_MSG(extack, 1226 "No egress device for nexthop gateway"); 1227 goto out; 1228 } 1229 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1230 if (!netif_carrier_ok(dev)) 1231 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1232 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1233 out: 1234 rcu_read_unlock(); 1235 return err; 1236 } 1237 1238 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1239 struct netlink_ext_ack *extack) 1240 { 1241 struct in_device *in_dev; 1242 int err; 1243 1244 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1245 NL_SET_ERR_MSG(extack, 1246 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1247 return -EINVAL; 1248 } 1249 1250 rcu_read_lock(); 1251 1252 err = -ENODEV; 1253 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1254 if (!in_dev) 1255 goto out; 1256 err = -ENETDOWN; 1257 if (!(in_dev->dev->flags & IFF_UP)) { 1258 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1259 goto out; 1260 } 1261 1262 nh->fib_nh_dev = in_dev->dev; 1263 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1264 nh->fib_nh_scope = RT_SCOPE_HOST; 1265 if (!netif_carrier_ok(nh->fib_nh_dev)) 1266 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1267 err = 0; 1268 out: 1269 rcu_read_unlock(); 1270 return err; 1271 } 1272 1273 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1274 struct netlink_ext_ack *extack) 1275 { 1276 int err; 1277 1278 if (nh->fib_nh_gw_family == AF_INET) 1279 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1280 else if (nh->fib_nh_gw_family == AF_INET6) 1281 err = fib_check_nh_v6_gw(net, nh, table, extack); 1282 else 1283 err = fib_check_nh_nongw(net, nh, extack); 1284 1285 return err; 1286 } 1287 1288 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1289 unsigned char scope) 1290 { 1291 struct fib_nh *nh; 1292 __be32 saddr; 1293 1294 if (nhc->nhc_family != AF_INET) 1295 return inet_select_addr(nhc->nhc_dev, 0, scope); 1296 1297 nh = container_of(nhc, struct fib_nh, nh_common); 1298 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1299 1300 WRITE_ONCE(nh->nh_saddr, saddr); 1301 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); 1302 1303 return saddr; 1304 } 1305 1306 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1307 { 1308 struct fib_nh_common *nhc = res->nhc; 1309 1310 if (res->fi->fib_prefsrc) 1311 return res->fi->fib_prefsrc; 1312 1313 if (nhc->nhc_family == AF_INET) { 1314 struct fib_nh *nh; 1315 1316 nh = container_of(nhc, struct fib_nh, nh_common); 1317 if (READ_ONCE(nh->nh_saddr_genid) == 1318 atomic_read(&net->ipv4.dev_addr_genid)) 1319 return READ_ONCE(nh->nh_saddr); 1320 } 1321 1322 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1323 } 1324 1325 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1326 { 1327 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1328 fib_prefsrc != cfg->fc_dst) { 1329 u32 tb_id = cfg->fc_table; 1330 int rc; 1331 1332 if (tb_id == RT_TABLE_MAIN) 1333 tb_id = RT_TABLE_LOCAL; 1334 1335 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1336 fib_prefsrc, tb_id); 1337 1338 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1339 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1340 fib_prefsrc, RT_TABLE_LOCAL); 1341 } 1342 1343 if (rc != RTN_LOCAL) 1344 return false; 1345 } 1346 return true; 1347 } 1348 1349 struct fib_info *fib_create_info(struct fib_config *cfg, 1350 struct netlink_ext_ack *extack) 1351 { 1352 int err; 1353 struct fib_info *fi = NULL; 1354 struct nexthop *nh = NULL; 1355 struct fib_info *ofi; 1356 int nhs = 1; 1357 struct net *net = cfg->fc_nlinfo.nl_net; 1358 1359 ASSERT_RTNL(); 1360 if (cfg->fc_type > RTN_MAX) 1361 goto err_inval; 1362 1363 /* Fast check to catch the most weird cases */ 1364 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1365 NL_SET_ERR_MSG(extack, "Invalid scope"); 1366 goto err_inval; 1367 } 1368 1369 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1370 NL_SET_ERR_MSG(extack, 1371 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1372 goto err_inval; 1373 } 1374 1375 if (cfg->fc_nh_id) { 1376 if (!cfg->fc_mx) { 1377 fi = fib_find_info_nh(net, cfg); 1378 if (fi) { 1379 refcount_inc(&fi->fib_treeref); 1380 return fi; 1381 } 1382 } 1383 1384 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1385 if (!nh) { 1386 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1387 goto err_inval; 1388 } 1389 nhs = 0; 1390 } 1391 1392 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1393 if (cfg->fc_mp) { 1394 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1395 if (nhs == 0) 1396 goto err_inval; 1397 } 1398 #endif 1399 1400 fib_info_hash_grow(net); 1401 1402 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1403 if (!fi) { 1404 err = -ENOBUFS; 1405 goto failure; 1406 } 1407 1408 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack); 1409 if (IS_ERR(fi->fib_metrics)) { 1410 err = PTR_ERR(fi->fib_metrics); 1411 kfree(fi); 1412 return ERR_PTR(err); 1413 } 1414 1415 fi->fib_net = net; 1416 fi->fib_protocol = cfg->fc_protocol; 1417 fi->fib_scope = cfg->fc_scope; 1418 fi->fib_flags = cfg->fc_flags; 1419 fi->fib_priority = cfg->fc_priority; 1420 fi->fib_prefsrc = cfg->fc_prefsrc; 1421 fi->fib_type = cfg->fc_type; 1422 fi->fib_tb_id = cfg->fc_table; 1423 1424 fi->fib_nhs = nhs; 1425 if (nh) { 1426 if (!nexthop_get(nh)) { 1427 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1428 err = -EINVAL; 1429 } else { 1430 err = 0; 1431 fi->nh = nh; 1432 } 1433 } else { 1434 change_nexthops(fi) { 1435 nexthop_nh->nh_parent = fi; 1436 } endfor_nexthops(fi) 1437 1438 if (cfg->fc_mp) 1439 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1440 extack); 1441 else 1442 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1443 } 1444 1445 if (err != 0) 1446 goto failure; 1447 1448 if (fib_props[cfg->fc_type].error) { 1449 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1450 NL_SET_ERR_MSG(extack, 1451 "Gateway, device and multipath can not be specified for this route type"); 1452 goto err_inval; 1453 } 1454 goto link_it; 1455 } else { 1456 switch (cfg->fc_type) { 1457 case RTN_UNICAST: 1458 case RTN_LOCAL: 1459 case RTN_BROADCAST: 1460 case RTN_ANYCAST: 1461 case RTN_MULTICAST: 1462 break; 1463 default: 1464 NL_SET_ERR_MSG(extack, "Invalid route type"); 1465 goto err_inval; 1466 } 1467 } 1468 1469 if (cfg->fc_scope > RT_SCOPE_HOST) { 1470 NL_SET_ERR_MSG(extack, "Invalid scope"); 1471 goto err_inval; 1472 } 1473 1474 if (fi->nh) { 1475 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1476 if (err) 1477 goto failure; 1478 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1479 struct fib_nh *nh = fi->fib_nh; 1480 1481 /* Local address is added. */ 1482 if (nhs != 1) { 1483 NL_SET_ERR_MSG(extack, 1484 "Route with host scope can not have multiple nexthops"); 1485 goto err_inval; 1486 } 1487 if (nh->fib_nh_gw_family) { 1488 NL_SET_ERR_MSG(extack, 1489 "Route with host scope can not have a gateway"); 1490 goto err_inval; 1491 } 1492 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1493 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1494 err = -ENODEV; 1495 if (!nh->fib_nh_dev) 1496 goto failure; 1497 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1498 GFP_KERNEL); 1499 } else { 1500 int linkdown = 0; 1501 1502 change_nexthops(fi) { 1503 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1504 cfg->fc_table, cfg->fc_scope, 1505 extack); 1506 if (err != 0) 1507 goto failure; 1508 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1509 linkdown++; 1510 } endfor_nexthops(fi) 1511 if (linkdown == fi->fib_nhs) 1512 fi->fib_flags |= RTNH_F_LINKDOWN; 1513 } 1514 1515 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1516 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1517 goto err_inval; 1518 } 1519 1520 if (!fi->nh) { 1521 change_nexthops(fi) { 1522 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1523 fi->fib_scope); 1524 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1525 fi->fib_nh_is_v6 = true; 1526 } endfor_nexthops(fi) 1527 1528 fib_rebalance(fi); 1529 } 1530 1531 link_it: 1532 ofi = fib_find_info(fi); 1533 if (ofi) { 1534 /* fib_table_lookup() should not see @fi yet. */ 1535 fi->fib_dead = 1; 1536 free_fib_info(fi); 1537 refcount_inc(&ofi->fib_treeref); 1538 return ofi; 1539 } 1540 1541 refcount_set(&fi->fib_treeref, 1); 1542 refcount_set(&fi->fib_clntref, 1); 1543 1544 net->ipv4.fib_info_cnt++; 1545 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi)); 1546 1547 if (fi->fib_prefsrc) { 1548 struct hlist_head *head; 1549 1550 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1551 hlist_add_head(&fi->fib_lhash, head); 1552 } 1553 if (fi->nh) { 1554 list_add(&fi->nh_list, &nh->fi_list); 1555 } else { 1556 change_nexthops(fi) { 1557 struct hlist_head *head; 1558 1559 if (!nexthop_nh->fib_nh_dev) 1560 continue; 1561 head = fib_nh_head(nexthop_nh->fib_nh_dev); 1562 hlist_add_head_rcu(&nexthop_nh->nh_hash, head); 1563 } endfor_nexthops(fi) 1564 } 1565 return fi; 1566 1567 err_inval: 1568 err = -EINVAL; 1569 1570 failure: 1571 if (fi) { 1572 /* fib_table_lookup() should not see @fi yet. */ 1573 fi->fib_dead = 1; 1574 free_fib_info(fi); 1575 } 1576 1577 return ERR_PTR(err); 1578 } 1579 1580 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1581 u8 rt_family, unsigned char *flags, bool skip_oif) 1582 { 1583 if (nhc->nhc_flags & RTNH_F_DEAD) 1584 *flags |= RTNH_F_DEAD; 1585 1586 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1587 *flags |= RTNH_F_LINKDOWN; 1588 1589 rcu_read_lock(); 1590 switch (nhc->nhc_family) { 1591 case AF_INET: 1592 if (ip_ignore_linkdown(nhc->nhc_dev)) 1593 *flags |= RTNH_F_DEAD; 1594 break; 1595 case AF_INET6: 1596 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1597 *flags |= RTNH_F_DEAD; 1598 break; 1599 } 1600 rcu_read_unlock(); 1601 } 1602 1603 switch (nhc->nhc_gw_family) { 1604 case AF_INET: 1605 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1606 goto nla_put_failure; 1607 break; 1608 case AF_INET6: 1609 /* if gateway family does not match nexthop family 1610 * gateway is encoded as RTA_VIA 1611 */ 1612 if (rt_family != nhc->nhc_gw_family) { 1613 int alen = sizeof(struct in6_addr); 1614 struct nlattr *nla; 1615 struct rtvia *via; 1616 1617 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1618 if (!nla) 1619 goto nla_put_failure; 1620 1621 via = nla_data(nla); 1622 via->rtvia_family = AF_INET6; 1623 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1624 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1625 &nhc->nhc_gw.ipv6) < 0) { 1626 goto nla_put_failure; 1627 } 1628 break; 1629 } 1630 1631 *flags |= (nhc->nhc_flags & 1632 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1633 1634 if (!skip_oif && nhc->nhc_dev && 1635 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1636 goto nla_put_failure; 1637 1638 if (lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1639 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1640 goto nla_put_failure; 1641 1642 return 0; 1643 1644 nla_put_failure: 1645 return -EMSGSIZE; 1646 } 1647 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1648 1649 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1650 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1651 int nh_weight, u8 rt_family, u32 nh_tclassid) 1652 { 1653 const struct net_device *dev = nhc->nhc_dev; 1654 struct rtnexthop *rtnh; 1655 unsigned char flags = 0; 1656 1657 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1658 if (!rtnh) 1659 goto nla_put_failure; 1660 1661 rtnh->rtnh_hops = nh_weight - 1; 1662 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1663 1664 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1665 goto nla_put_failure; 1666 1667 rtnh->rtnh_flags = flags; 1668 1669 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1670 goto nla_put_failure; 1671 1672 /* length of rtnetlink header + attributes */ 1673 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1674 1675 return 0; 1676 1677 nla_put_failure: 1678 return -EMSGSIZE; 1679 } 1680 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1681 #endif 1682 1683 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1684 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1685 { 1686 struct nlattr *mp; 1687 1688 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1689 if (!mp) 1690 goto nla_put_failure; 1691 1692 if (unlikely(fi->nh)) { 1693 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1694 goto nla_put_failure; 1695 goto mp_end; 1696 } 1697 1698 for_nexthops(fi) { 1699 u32 nh_tclassid = 0; 1700 #ifdef CONFIG_IP_ROUTE_CLASSID 1701 nh_tclassid = nh->nh_tclassid; 1702 #endif 1703 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1704 AF_INET, nh_tclassid) < 0) 1705 goto nla_put_failure; 1706 } endfor_nexthops(fi); 1707 1708 mp_end: 1709 nla_nest_end(skb, mp); 1710 1711 return 0; 1712 1713 nla_put_failure: 1714 return -EMSGSIZE; 1715 } 1716 #else 1717 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1718 { 1719 return 0; 1720 } 1721 #endif 1722 1723 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1724 const struct fib_rt_info *fri, unsigned int flags) 1725 { 1726 unsigned int nhs = fib_info_num_path(fri->fi); 1727 struct fib_info *fi = fri->fi; 1728 u32 tb_id = fri->tb_id; 1729 struct nlmsghdr *nlh; 1730 struct rtmsg *rtm; 1731 1732 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1733 if (!nlh) 1734 return -EMSGSIZE; 1735 1736 rtm = nlmsg_data(nlh); 1737 rtm->rtm_family = AF_INET; 1738 rtm->rtm_dst_len = fri->dst_len; 1739 rtm->rtm_src_len = 0; 1740 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); 1741 if (tb_id < 256) 1742 rtm->rtm_table = tb_id; 1743 else 1744 rtm->rtm_table = RT_TABLE_COMPAT; 1745 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1746 goto nla_put_failure; 1747 rtm->rtm_type = fri->type; 1748 rtm->rtm_flags = fi->fib_flags; 1749 rtm->rtm_scope = fi->fib_scope; 1750 rtm->rtm_protocol = fi->fib_protocol; 1751 1752 if (rtm->rtm_dst_len && 1753 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1754 goto nla_put_failure; 1755 if (fi->fib_priority && 1756 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1757 goto nla_put_failure; 1758 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1759 goto nla_put_failure; 1760 1761 if (fi->fib_prefsrc && 1762 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1763 goto nla_put_failure; 1764 1765 if (fi->nh) { 1766 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1767 goto nla_put_failure; 1768 if (nexthop_is_blackhole(fi->nh)) 1769 rtm->rtm_type = RTN_BLACKHOLE; 1770 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1771 goto offload; 1772 } 1773 1774 if (nhs == 1) { 1775 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1776 unsigned char flags = 0; 1777 1778 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1779 goto nla_put_failure; 1780 1781 rtm->rtm_flags = flags; 1782 #ifdef CONFIG_IP_ROUTE_CLASSID 1783 if (nhc->nhc_family == AF_INET) { 1784 struct fib_nh *nh; 1785 1786 nh = container_of(nhc, struct fib_nh, nh_common); 1787 if (nh->nh_tclassid && 1788 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1789 goto nla_put_failure; 1790 } 1791 #endif 1792 } else { 1793 if (fib_add_multipath(skb, fi) < 0) 1794 goto nla_put_failure; 1795 } 1796 1797 offload: 1798 if (fri->offload) 1799 rtm->rtm_flags |= RTM_F_OFFLOAD; 1800 if (fri->trap) 1801 rtm->rtm_flags |= RTM_F_TRAP; 1802 if (fri->offload_failed) 1803 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1804 1805 nlmsg_end(skb, nlh); 1806 return 0; 1807 1808 nla_put_failure: 1809 nlmsg_cancel(skb, nlh); 1810 return -EMSGSIZE; 1811 } 1812 1813 /* 1814 * Update FIB if: 1815 * - local address disappeared -> we must delete all the entries 1816 * referring to it. 1817 * - device went down -> we must shutdown all nexthops going via it. 1818 */ 1819 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1820 { 1821 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1822 struct net *net = dev_net(dev); 1823 struct hlist_head *head; 1824 struct fib_info *fi; 1825 int ret = 0; 1826 1827 if (!local) 1828 return 0; 1829 1830 head = fib_info_laddrhash_bucket(net, local); 1831 hlist_for_each_entry(fi, head, fib_lhash) { 1832 if (!net_eq(fi->fib_net, net) || 1833 fi->fib_tb_id != tb_id) 1834 continue; 1835 if (fi->fib_prefsrc == local) { 1836 fi->fib_flags |= RTNH_F_DEAD; 1837 fi->pfsrc_removed = true; 1838 ret++; 1839 } 1840 } 1841 return ret; 1842 } 1843 1844 static int call_fib_nh_notifiers(struct fib_nh *nh, 1845 enum fib_event_type event_type) 1846 { 1847 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1848 struct fib_nh_notifier_info info = { 1849 .fib_nh = nh, 1850 }; 1851 1852 switch (event_type) { 1853 case FIB_EVENT_NH_ADD: 1854 if (nh->fib_nh_flags & RTNH_F_DEAD) 1855 break; 1856 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1857 break; 1858 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1859 &info.info); 1860 case FIB_EVENT_NH_DEL: 1861 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1862 (nh->fib_nh_flags & RTNH_F_DEAD)) 1863 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1864 event_type, &info.info); 1865 break; 1866 default: 1867 break; 1868 } 1869 1870 return NOTIFY_DONE; 1871 } 1872 1873 /* Update the PMTU of exceptions when: 1874 * - the new MTU of the first hop becomes smaller than the PMTU 1875 * - the old MTU was the same as the PMTU, and it limited discovery of 1876 * larger MTUs on the path. With that limit raised, we can now 1877 * discover larger MTUs 1878 * A special case is locked exceptions, for which the PMTU is smaller 1879 * than the minimal accepted PMTU: 1880 * - if the new MTU is greater than the PMTU, don't make any change 1881 * - otherwise, unlock and set PMTU 1882 */ 1883 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1884 { 1885 struct fnhe_hash_bucket *bucket; 1886 int i; 1887 1888 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1889 if (!bucket) 1890 return; 1891 1892 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1893 struct fib_nh_exception *fnhe; 1894 1895 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1896 fnhe; 1897 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1898 if (fnhe->fnhe_mtu_locked) { 1899 if (new <= fnhe->fnhe_pmtu) { 1900 fnhe->fnhe_pmtu = new; 1901 fnhe->fnhe_mtu_locked = false; 1902 } 1903 } else if (new < fnhe->fnhe_pmtu || 1904 orig == fnhe->fnhe_pmtu) { 1905 fnhe->fnhe_pmtu = new; 1906 } 1907 } 1908 } 1909 } 1910 1911 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1912 { 1913 struct hlist_head *head = fib_nh_head(dev); 1914 struct fib_nh *nh; 1915 1916 hlist_for_each_entry(nh, head, nh_hash) { 1917 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); 1918 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1919 } 1920 } 1921 1922 /* Event force Flags Description 1923 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1924 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1925 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1926 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1927 * 1928 * only used when fib_nh is built into fib_info 1929 */ 1930 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1931 { 1932 struct hlist_head *head = fib_nh_head(dev); 1933 struct fib_info *prev_fi = NULL; 1934 int scope = RT_SCOPE_NOWHERE; 1935 struct fib_nh *nh; 1936 int ret = 0; 1937 1938 if (force) 1939 scope = -1; 1940 1941 hlist_for_each_entry(nh, head, nh_hash) { 1942 struct fib_info *fi = nh->nh_parent; 1943 int dead; 1944 1945 BUG_ON(!fi->fib_nhs); 1946 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); 1947 if (fi == prev_fi) 1948 continue; 1949 prev_fi = fi; 1950 dead = 0; 1951 change_nexthops(fi) { 1952 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1953 dead++; 1954 else if (nexthop_nh->fib_nh_dev == dev && 1955 nexthop_nh->fib_nh_scope != scope) { 1956 switch (event) { 1957 case NETDEV_DOWN: 1958 case NETDEV_UNREGISTER: 1959 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 1960 fallthrough; 1961 case NETDEV_CHANGE: 1962 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1963 break; 1964 } 1965 call_fib_nh_notifiers(nexthop_nh, 1966 FIB_EVENT_NH_DEL); 1967 dead++; 1968 } 1969 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1970 if (event == NETDEV_UNREGISTER && 1971 nexthop_nh->fib_nh_dev == dev) { 1972 dead = fi->fib_nhs; 1973 break; 1974 } 1975 #endif 1976 } endfor_nexthops(fi) 1977 if (dead == fi->fib_nhs) { 1978 switch (event) { 1979 case NETDEV_DOWN: 1980 case NETDEV_UNREGISTER: 1981 fi->fib_flags |= RTNH_F_DEAD; 1982 fallthrough; 1983 case NETDEV_CHANGE: 1984 fi->fib_flags |= RTNH_F_LINKDOWN; 1985 break; 1986 } 1987 ret++; 1988 } 1989 1990 fib_rebalance(fi); 1991 } 1992 1993 return ret; 1994 } 1995 1996 /* Must be invoked inside of an RCU protected region. */ 1997 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1998 { 1999 struct fib_info *fi = NULL, *last_resort = NULL; 2000 struct hlist_head *fa_head = res->fa_head; 2001 struct fib_table *tb = res->table; 2002 u8 slen = 32 - res->prefixlen; 2003 int order = -1, last_idx = -1; 2004 struct fib_alias *fa, *fa1 = NULL; 2005 u32 last_prio = res->fi->fib_priority; 2006 dscp_t last_dscp = 0; 2007 2008 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2009 struct fib_info *next_fi = fa->fa_info; 2010 struct fib_nh_common *nhc; 2011 2012 if (fa->fa_slen != slen) 2013 continue; 2014 if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp)) 2015 continue; 2016 if (fa->tb_id != tb->tb_id) 2017 continue; 2018 if (next_fi->fib_priority > last_prio && 2019 fa->fa_dscp == last_dscp) { 2020 if (last_dscp) 2021 continue; 2022 break; 2023 } 2024 if (next_fi->fib_flags & RTNH_F_DEAD) 2025 continue; 2026 last_dscp = fa->fa_dscp; 2027 last_prio = next_fi->fib_priority; 2028 2029 if (next_fi->fib_scope != res->scope || 2030 fa->fa_type != RTN_UNICAST) 2031 continue; 2032 2033 nhc = fib_info_nhc(next_fi, 0); 2034 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2035 continue; 2036 2037 fib_alias_accessed(fa); 2038 2039 if (!fi) { 2040 if (next_fi != res->fi) 2041 break; 2042 fa1 = fa; 2043 } else if (!fib_detect_death(fi, order, &last_resort, 2044 &last_idx, fa1->fa_default)) { 2045 fib_result_assign(res, fi); 2046 fa1->fa_default = order; 2047 goto out; 2048 } 2049 fi = next_fi; 2050 order++; 2051 } 2052 2053 if (order <= 0 || !fi) { 2054 if (fa1) 2055 fa1->fa_default = -1; 2056 goto out; 2057 } 2058 2059 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2060 fa1->fa_default)) { 2061 fib_result_assign(res, fi); 2062 fa1->fa_default = order; 2063 goto out; 2064 } 2065 2066 if (last_idx >= 0) 2067 fib_result_assign(res, last_resort); 2068 fa1->fa_default = last_idx; 2069 out: 2070 return; 2071 } 2072 2073 /* 2074 * Dead device goes up. We wake up dead nexthops. 2075 * It takes sense only on multipath routes. 2076 * 2077 * only used when fib_nh is built into fib_info 2078 */ 2079 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2080 { 2081 struct fib_info *prev_fi; 2082 struct hlist_head *head; 2083 struct fib_nh *nh; 2084 int ret; 2085 2086 if (!(dev->flags & IFF_UP)) 2087 return 0; 2088 2089 if (nh_flags & RTNH_F_DEAD) { 2090 unsigned int flags = netif_get_flags(dev); 2091 2092 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2093 nh_flags |= RTNH_F_LINKDOWN; 2094 } 2095 2096 prev_fi = NULL; 2097 head = fib_nh_head(dev); 2098 ret = 0; 2099 2100 hlist_for_each_entry(nh, head, nh_hash) { 2101 struct fib_info *fi = nh->nh_parent; 2102 int alive; 2103 2104 BUG_ON(!fi->fib_nhs); 2105 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); 2106 if (fi == prev_fi) 2107 continue; 2108 2109 prev_fi = fi; 2110 alive = 0; 2111 change_nexthops(fi) { 2112 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2113 alive++; 2114 continue; 2115 } 2116 if (!nexthop_nh->fib_nh_dev || 2117 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2118 continue; 2119 if (nexthop_nh->fib_nh_dev != dev || 2120 !__in_dev_get_rtnl(dev)) 2121 continue; 2122 alive++; 2123 nexthop_nh->fib_nh_flags &= ~nh_flags; 2124 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2125 } endfor_nexthops(fi) 2126 2127 if (alive > 0) { 2128 fi->fib_flags &= ~nh_flags; 2129 ret++; 2130 } 2131 2132 fib_rebalance(fi); 2133 } 2134 2135 return ret; 2136 } 2137 2138 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2139 static bool fib_good_nh(const struct fib_nh *nh) 2140 { 2141 int state = NUD_REACHABLE; 2142 2143 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2144 struct neighbour *n; 2145 2146 rcu_read_lock(); 2147 2148 if (likely(nh->fib_nh_gw_family == AF_INET)) 2149 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2150 (__force u32)nh->fib_nh_gw4); 2151 else if (nh->fib_nh_gw_family == AF_INET6) 2152 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2153 &nh->fib_nh_gw6); 2154 else 2155 n = NULL; 2156 if (n) 2157 state = READ_ONCE(n->nud_state); 2158 2159 rcu_read_unlock(); 2160 } 2161 2162 return !!(state & NUD_VALID); 2163 } 2164 2165 void fib_select_multipath(struct fib_result *res, int hash, 2166 const struct flowi4 *fl4) 2167 { 2168 struct fib_info *fi = res->fi; 2169 struct net *net = fi->fib_net; 2170 bool found = false; 2171 bool use_neigh; 2172 __be32 saddr; 2173 2174 if (unlikely(res->fi->nh)) { 2175 nexthop_path_fib_result(res, hash); 2176 return; 2177 } 2178 2179 use_neigh = READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh); 2180 saddr = fl4 ? fl4->saddr : 0; 2181 2182 change_nexthops(fi) { 2183 int nh_upper_bound; 2184 2185 /* Nexthops without a carrier are assigned an upper bound of 2186 * minus one when "ignore_routes_with_linkdown" is set. 2187 */ 2188 nh_upper_bound = atomic_read(&nexthop_nh->fib_nh_upper_bound); 2189 if (nh_upper_bound == -1 || 2190 (use_neigh && !fib_good_nh(nexthop_nh))) 2191 continue; 2192 2193 if (!found) { 2194 res->nh_sel = nhsel; 2195 res->nhc = &nexthop_nh->nh_common; 2196 found = !saddr || nexthop_nh->nh_saddr == saddr; 2197 } 2198 2199 if (hash > nh_upper_bound) 2200 continue; 2201 2202 if (!saddr || nexthop_nh->nh_saddr == saddr) { 2203 res->nh_sel = nhsel; 2204 res->nhc = &nexthop_nh->nh_common; 2205 return; 2206 } 2207 2208 if (found) 2209 return; 2210 2211 } endfor_nexthops(fi); 2212 } 2213 #endif 2214 2215 void fib_select_path(struct net *net, struct fib_result *res, 2216 struct flowi4 *fl4, const struct sk_buff *skb) 2217 { 2218 if (fl4->flowi4_oif) 2219 goto check_saddr; 2220 2221 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2222 if (fib_info_num_path(res->fi) > 1) { 2223 int h = fib_multipath_hash(net, fl4, skb, NULL); 2224 2225 fib_select_multipath(res, h, fl4); 2226 } 2227 else 2228 #endif 2229 if (!res->prefixlen && 2230 res->table->tb_num_default > 1 && 2231 res->type == RTN_UNICAST) 2232 fib_select_default(fl4, res); 2233 2234 check_saddr: 2235 if (!fl4->saddr) { 2236 struct net_device *l3mdev; 2237 2238 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev); 2239 2240 if (!l3mdev || 2241 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev) 2242 fl4->saddr = fib_result_prefsrc(net, res); 2243 else 2244 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK); 2245 } 2246 } 2247 2248 int __net_init fib4_semantics_init(struct net *net) 2249 { 2250 unsigned int hash_bits = 4; 2251 2252 net->ipv4.fib_info_hash = fib_info_hash_alloc(hash_bits); 2253 if (!net->ipv4.fib_info_hash) 2254 return -ENOMEM; 2255 2256 net->ipv4.fib_info_hash_bits = hash_bits; 2257 net->ipv4.fib_info_cnt = 0; 2258 2259 return 0; 2260 } 2261 2262 void __net_exit fib4_semantics_exit(struct net *net) 2263 { 2264 fib_info_hash_free(net->ipv4.fib_info_hash); 2265 } 2266