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 34 #include <net/arp.h> 35 #include <net/inet_dscp.h> 36 #include <net/ip.h> 37 #include <net/protocol.h> 38 #include <net/route.h> 39 #include <net/tcp.h> 40 #include <net/sock.h> 41 #include <net/ip_fib.h> 42 #include <net/ip6_fib.h> 43 #include <net/nexthop.h> 44 #include <net/netlink.h> 45 #include <net/rtnh.h> 46 #include <net/lwtunnel.h> 47 #include <net/fib_notifier.h> 48 #include <net/addrconf.h> 49 50 #include "fib_lookup.h" 51 52 static DEFINE_SPINLOCK(fib_info_lock); 53 static struct hlist_head *fib_info_hash; 54 static struct hlist_head *fib_info_laddrhash; 55 static unsigned int fib_info_hash_size; 56 static unsigned int fib_info_hash_bits; 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 /* for_nexthops and change_nexthops only used when nexthop object 64 * is not set in a fib_info. The logic within can reference fib_nh. 65 */ 66 #ifdef CONFIG_IP_ROUTE_MULTIPATH 67 68 #define for_nexthops(fi) { \ 69 int nhsel; const struct fib_nh *nh; \ 70 for (nhsel = 0, nh = (fi)->fib_nh; \ 71 nhsel < fib_info_num_path((fi)); \ 72 nh++, nhsel++) 73 74 #define change_nexthops(fi) { \ 75 int nhsel; struct fib_nh *nexthop_nh; \ 76 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 77 nhsel < fib_info_num_path((fi)); \ 78 nexthop_nh++, nhsel++) 79 80 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 81 82 /* Hope, that gcc will optimize it to get rid of dummy loop */ 83 84 #define for_nexthops(fi) { \ 85 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 86 for (nhsel = 0; nhsel < 1; nhsel++) 87 88 #define change_nexthops(fi) { \ 89 int nhsel; \ 90 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 91 for (nhsel = 0; nhsel < 1; nhsel++) 92 93 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 94 95 #define endfor_nexthops(fi) } 96 97 98 const struct fib_prop fib_props[RTN_MAX + 1] = { 99 [RTN_UNSPEC] = { 100 .error = 0, 101 .scope = RT_SCOPE_NOWHERE, 102 }, 103 [RTN_UNICAST] = { 104 .error = 0, 105 .scope = RT_SCOPE_UNIVERSE, 106 }, 107 [RTN_LOCAL] = { 108 .error = 0, 109 .scope = RT_SCOPE_HOST, 110 }, 111 [RTN_BROADCAST] = { 112 .error = 0, 113 .scope = RT_SCOPE_LINK, 114 }, 115 [RTN_ANYCAST] = { 116 .error = 0, 117 .scope = RT_SCOPE_LINK, 118 }, 119 [RTN_MULTICAST] = { 120 .error = 0, 121 .scope = RT_SCOPE_UNIVERSE, 122 }, 123 [RTN_BLACKHOLE] = { 124 .error = -EINVAL, 125 .scope = RT_SCOPE_UNIVERSE, 126 }, 127 [RTN_UNREACHABLE] = { 128 .error = -EHOSTUNREACH, 129 .scope = RT_SCOPE_UNIVERSE, 130 }, 131 [RTN_PROHIBIT] = { 132 .error = -EACCES, 133 .scope = RT_SCOPE_UNIVERSE, 134 }, 135 [RTN_THROW] = { 136 .error = -EAGAIN, 137 .scope = RT_SCOPE_UNIVERSE, 138 }, 139 [RTN_NAT] = { 140 .error = -EINVAL, 141 .scope = RT_SCOPE_NOWHERE, 142 }, 143 [RTN_XRESOLVE] = { 144 .error = -EINVAL, 145 .scope = RT_SCOPE_NOWHERE, 146 }, 147 }; 148 149 static void rt_fibinfo_free(struct rtable __rcu **rtp) 150 { 151 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 152 153 if (!rt) 154 return; 155 156 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 157 * because we waited an RCU grace period before calling 158 * free_fib_info_rcu() 159 */ 160 161 dst_dev_put(&rt->dst); 162 dst_release_immediate(&rt->dst); 163 } 164 165 static void free_nh_exceptions(struct fib_nh_common *nhc) 166 { 167 struct fnhe_hash_bucket *hash; 168 int i; 169 170 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); 171 if (!hash) 172 return; 173 for (i = 0; i < FNHE_HASH_SIZE; i++) { 174 struct fib_nh_exception *fnhe; 175 176 fnhe = rcu_dereference_protected(hash[i].chain, 1); 177 while (fnhe) { 178 struct fib_nh_exception *next; 179 180 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 181 182 rt_fibinfo_free(&fnhe->fnhe_rth_input); 183 rt_fibinfo_free(&fnhe->fnhe_rth_output); 184 185 kfree(fnhe); 186 187 fnhe = next; 188 } 189 } 190 kfree(hash); 191 } 192 193 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 194 { 195 int cpu; 196 197 if (!rtp) 198 return; 199 200 for_each_possible_cpu(cpu) { 201 struct rtable *rt; 202 203 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 204 if (rt) { 205 dst_dev_put(&rt->dst); 206 dst_release_immediate(&rt->dst); 207 } 208 } 209 free_percpu(rtp); 210 } 211 212 void fib_nh_common_release(struct fib_nh_common *nhc) 213 { 214 dev_put_track(nhc->nhc_dev, &nhc->nhc_dev_tracker); 215 lwtstate_put(nhc->nhc_lwtstate); 216 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 217 rt_fibinfo_free(&nhc->nhc_rth_input); 218 free_nh_exceptions(nhc); 219 } 220 EXPORT_SYMBOL_GPL(fib_nh_common_release); 221 222 void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 223 { 224 #ifdef CONFIG_IP_ROUTE_CLASSID 225 if (fib_nh->nh_tclassid) 226 atomic_dec(&net->ipv4.fib_num_tclassid_users); 227 #endif 228 fib_nh_common_release(&fib_nh->nh_common); 229 } 230 231 /* Release a nexthop info record */ 232 static void free_fib_info_rcu(struct rcu_head *head) 233 { 234 struct fib_info *fi = container_of(head, struct fib_info, rcu); 235 236 if (fi->nh) { 237 nexthop_put(fi->nh); 238 } else { 239 change_nexthops(fi) { 240 fib_nh_release(fi->fib_net, nexthop_nh); 241 } endfor_nexthops(fi); 242 } 243 244 ip_fib_metrics_put(fi->fib_metrics); 245 246 kfree(fi); 247 } 248 249 void free_fib_info(struct fib_info *fi) 250 { 251 if (fi->fib_dead == 0) { 252 pr_warn("Freeing alive fib_info %p\n", fi); 253 return; 254 } 255 256 call_rcu(&fi->rcu, free_fib_info_rcu); 257 } 258 EXPORT_SYMBOL_GPL(free_fib_info); 259 260 void fib_release_info(struct fib_info *fi) 261 { 262 spin_lock_bh(&fib_info_lock); 263 if (fi && refcount_dec_and_test(&fi->fib_treeref)) { 264 hlist_del(&fi->fib_hash); 265 266 /* Paired with READ_ONCE() in fib_create_info(). */ 267 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1); 268 269 if (fi->fib_prefsrc) 270 hlist_del(&fi->fib_lhash); 271 if (fi->nh) { 272 list_del(&fi->nh_list); 273 } else { 274 change_nexthops(fi) { 275 if (!nexthop_nh->fib_nh_dev) 276 continue; 277 hlist_del(&nexthop_nh->nh_hash); 278 } endfor_nexthops(fi) 279 } 280 fi->fib_dead = 1; 281 fib_info_put(fi); 282 } 283 spin_unlock_bh(&fib_info_lock); 284 } 285 286 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 287 { 288 const struct fib_nh *onh; 289 290 if (fi->nh || ofi->nh) 291 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 292 293 if (ofi->fib_nhs == 0) 294 return 0; 295 296 for_nexthops(fi) { 297 onh = fib_info_nh(ofi, nhsel); 298 299 if (nh->fib_nh_oif != onh->fib_nh_oif || 300 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 301 nh->fib_nh_scope != onh->fib_nh_scope || 302 #ifdef CONFIG_IP_ROUTE_MULTIPATH 303 nh->fib_nh_weight != onh->fib_nh_weight || 304 #endif 305 #ifdef CONFIG_IP_ROUTE_CLASSID 306 nh->nh_tclassid != onh->nh_tclassid || 307 #endif 308 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 309 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 310 return -1; 311 312 if (nh->fib_nh_gw_family == AF_INET && 313 nh->fib_nh_gw4 != onh->fib_nh_gw4) 314 return -1; 315 316 if (nh->fib_nh_gw_family == AF_INET6 && 317 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 318 return -1; 319 } endfor_nexthops(fi); 320 return 0; 321 } 322 323 static inline unsigned int fib_devindex_hashfn(unsigned int val) 324 { 325 return hash_32(val, DEVINDEX_HASHBITS); 326 } 327 328 static struct hlist_head * 329 fib_info_devhash_bucket(const struct net_device *dev) 330 { 331 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex; 332 333 return &fib_info_devhash[fib_devindex_hashfn(val)]; 334 } 335 336 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 337 u32 prefsrc, u32 priority) 338 { 339 unsigned int val = init_val; 340 341 val ^= (protocol << 8) | scope; 342 val ^= prefsrc; 343 val ^= priority; 344 345 return val; 346 } 347 348 static unsigned int fib_info_hashfn_result(unsigned int val) 349 { 350 unsigned int mask = (fib_info_hash_size - 1); 351 352 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 353 } 354 355 static inline unsigned int fib_info_hashfn(struct fib_info *fi) 356 { 357 unsigned int val; 358 359 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 360 fi->fib_scope, (__force u32)fi->fib_prefsrc, 361 fi->fib_priority); 362 363 if (fi->nh) { 364 val ^= fib_devindex_hashfn(fi->nh->id); 365 } else { 366 for_nexthops(fi) { 367 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 368 } endfor_nexthops(fi) 369 } 370 371 return fib_info_hashfn_result(val); 372 } 373 374 /* no metrics, only nexthop id */ 375 static struct fib_info *fib_find_info_nh(struct net *net, 376 const struct fib_config *cfg) 377 { 378 struct hlist_head *head; 379 struct fib_info *fi; 380 unsigned int hash; 381 382 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 383 cfg->fc_protocol, cfg->fc_scope, 384 (__force u32)cfg->fc_prefsrc, 385 cfg->fc_priority); 386 hash = fib_info_hashfn_result(hash); 387 head = &fib_info_hash[hash]; 388 389 hlist_for_each_entry(fi, head, fib_hash) { 390 if (!net_eq(fi->fib_net, net)) 391 continue; 392 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 393 continue; 394 if (cfg->fc_protocol == fi->fib_protocol && 395 cfg->fc_scope == fi->fib_scope && 396 cfg->fc_prefsrc == fi->fib_prefsrc && 397 cfg->fc_priority == fi->fib_priority && 398 cfg->fc_type == fi->fib_type && 399 cfg->fc_table == fi->fib_tb_id && 400 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 401 return fi; 402 } 403 404 return NULL; 405 } 406 407 static struct fib_info *fib_find_info(struct fib_info *nfi) 408 { 409 struct hlist_head *head; 410 struct fib_info *fi; 411 unsigned int hash; 412 413 hash = fib_info_hashfn(nfi); 414 head = &fib_info_hash[hash]; 415 416 hlist_for_each_entry(fi, head, fib_hash) { 417 if (!net_eq(fi->fib_net, nfi->fib_net)) 418 continue; 419 if (fi->fib_nhs != nfi->fib_nhs) 420 continue; 421 if (nfi->fib_protocol == fi->fib_protocol && 422 nfi->fib_scope == fi->fib_scope && 423 nfi->fib_prefsrc == fi->fib_prefsrc && 424 nfi->fib_priority == fi->fib_priority && 425 nfi->fib_type == fi->fib_type && 426 memcmp(nfi->fib_metrics, fi->fib_metrics, 427 sizeof(u32) * RTAX_MAX) == 0 && 428 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 429 nh_comp(fi, nfi) == 0) 430 return fi; 431 } 432 433 return NULL; 434 } 435 436 /* Check, that the gateway is already configured. 437 * Used only by redirect accept routine. 438 */ 439 int ip_fib_check_default(__be32 gw, struct net_device *dev) 440 { 441 struct hlist_head *head; 442 struct fib_nh *nh; 443 444 spin_lock(&fib_info_lock); 445 446 head = fib_info_devhash_bucket(dev); 447 448 hlist_for_each_entry(nh, head, nh_hash) { 449 if (nh->fib_nh_dev == dev && 450 nh->fib_nh_gw4 == gw && 451 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 452 spin_unlock(&fib_info_lock); 453 return 0; 454 } 455 } 456 457 spin_unlock(&fib_info_lock); 458 459 return -1; 460 } 461 462 size_t fib_nlmsg_size(struct fib_info *fi) 463 { 464 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 465 + nla_total_size(4) /* RTA_TABLE */ 466 + nla_total_size(4) /* RTA_DST */ 467 + nla_total_size(4) /* RTA_PRIORITY */ 468 + nla_total_size(4) /* RTA_PREFSRC */ 469 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 470 unsigned int nhs = fib_info_num_path(fi); 471 472 /* space for nested metrics */ 473 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 474 475 if (fi->nh) 476 payload += nla_total_size(4); /* RTA_NH_ID */ 477 478 if (nhs) { 479 size_t nh_encapsize = 0; 480 /* Also handles the special case nhs == 1 */ 481 482 /* each nexthop is packed in an attribute */ 483 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 484 unsigned int i; 485 486 /* may contain flow and gateway attribute */ 487 nhsize += 2 * nla_total_size(4); 488 489 /* grab encap info */ 490 for (i = 0; i < fib_info_num_path(fi); i++) { 491 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 492 493 if (nhc->nhc_lwtstate) { 494 /* RTA_ENCAP_TYPE */ 495 nh_encapsize += lwtunnel_get_encap_size( 496 nhc->nhc_lwtstate); 497 /* RTA_ENCAP */ 498 nh_encapsize += nla_total_size(2); 499 } 500 } 501 502 /* all nexthops are packed in a nested attribute */ 503 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 504 505 } 506 507 return payload; 508 } 509 510 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 511 int dst_len, u32 tb_id, const struct nl_info *info, 512 unsigned int nlm_flags) 513 { 514 struct fib_rt_info fri; 515 struct sk_buff *skb; 516 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 517 int err = -ENOBUFS; 518 519 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 520 if (!skb) 521 goto errout; 522 523 fri.fi = fa->fa_info; 524 fri.tb_id = tb_id; 525 fri.dst = key; 526 fri.dst_len = dst_len; 527 fri.tos = inet_dscp_to_dsfield(fa->fa_dscp); 528 fri.type = fa->fa_type; 529 fri.offload = READ_ONCE(fa->offload); 530 fri.trap = READ_ONCE(fa->trap); 531 fri.offload_failed = READ_ONCE(fa->offload_failed); 532 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 533 if (err < 0) { 534 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 535 WARN_ON(err == -EMSGSIZE); 536 kfree_skb(skb); 537 goto errout; 538 } 539 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 540 info->nlh, GFP_KERNEL); 541 return; 542 errout: 543 if (err < 0) 544 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 545 } 546 547 static int fib_detect_death(struct fib_info *fi, int order, 548 struct fib_info **last_resort, int *last_idx, 549 int dflt) 550 { 551 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 552 struct neighbour *n; 553 int state = NUD_NONE; 554 555 if (likely(nhc->nhc_gw_family == AF_INET)) 556 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 557 else if (nhc->nhc_gw_family == AF_INET6) 558 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 559 nhc->nhc_dev); 560 else 561 n = NULL; 562 563 if (n) { 564 state = n->nud_state; 565 neigh_release(n); 566 } else { 567 return 0; 568 } 569 if (state == NUD_REACHABLE) 570 return 0; 571 if ((state & NUD_VALID) && order != dflt) 572 return 0; 573 if ((state & NUD_VALID) || 574 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 575 *last_resort = fi; 576 *last_idx = order; 577 } 578 return 1; 579 } 580 581 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 582 struct nlattr *encap, u16 encap_type, 583 void *cfg, gfp_t gfp_flags, 584 struct netlink_ext_ack *extack) 585 { 586 int err; 587 588 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 589 gfp_flags); 590 if (!nhc->nhc_pcpu_rth_output) 591 return -ENOMEM; 592 593 if (encap) { 594 struct lwtunnel_state *lwtstate; 595 596 if (encap_type == LWTUNNEL_ENCAP_NONE) { 597 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 598 err = -EINVAL; 599 goto lwt_failure; 600 } 601 err = lwtunnel_build_state(net, encap_type, encap, 602 nhc->nhc_family, cfg, &lwtstate, 603 extack); 604 if (err) 605 goto lwt_failure; 606 607 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 608 } 609 610 return 0; 611 612 lwt_failure: 613 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 614 nhc->nhc_pcpu_rth_output = NULL; 615 return err; 616 } 617 EXPORT_SYMBOL_GPL(fib_nh_common_init); 618 619 int fib_nh_init(struct net *net, struct fib_nh *nh, 620 struct fib_config *cfg, int nh_weight, 621 struct netlink_ext_ack *extack) 622 { 623 int err; 624 625 nh->fib_nh_family = AF_INET; 626 627 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 628 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 629 if (err) 630 return err; 631 632 nh->fib_nh_oif = cfg->fc_oif; 633 nh->fib_nh_gw_family = cfg->fc_gw_family; 634 if (cfg->fc_gw_family == AF_INET) 635 nh->fib_nh_gw4 = cfg->fc_gw4; 636 else if (cfg->fc_gw_family == AF_INET6) 637 nh->fib_nh_gw6 = cfg->fc_gw6; 638 639 nh->fib_nh_flags = cfg->fc_flags; 640 641 #ifdef CONFIG_IP_ROUTE_CLASSID 642 nh->nh_tclassid = cfg->fc_flow; 643 if (nh->nh_tclassid) 644 atomic_inc(&net->ipv4.fib_num_tclassid_users); 645 #endif 646 #ifdef CONFIG_IP_ROUTE_MULTIPATH 647 nh->fib_nh_weight = nh_weight; 648 #endif 649 return 0; 650 } 651 652 #ifdef CONFIG_IP_ROUTE_MULTIPATH 653 654 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 655 struct netlink_ext_ack *extack) 656 { 657 int nhs = 0; 658 659 while (rtnh_ok(rtnh, remaining)) { 660 nhs++; 661 rtnh = rtnh_next(rtnh, &remaining); 662 } 663 664 /* leftover implies invalid nexthop configuration, discard it */ 665 if (remaining > 0) { 666 NL_SET_ERR_MSG(extack, 667 "Invalid nexthop configuration - extra data after nexthops"); 668 nhs = 0; 669 } 670 671 return nhs; 672 } 673 674 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 675 struct netlink_ext_ack *extack) 676 { 677 if (nla_len(nla) < sizeof(*gw)) { 678 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 679 return -EINVAL; 680 } 681 682 *gw = nla_get_in_addr(nla); 683 684 return 0; 685 } 686 687 /* only called when fib_nh is integrated into fib_info */ 688 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 689 int remaining, struct fib_config *cfg, 690 struct netlink_ext_ack *extack) 691 { 692 struct net *net = fi->fib_net; 693 struct fib_config fib_cfg; 694 struct fib_nh *nh; 695 int ret; 696 697 change_nexthops(fi) { 698 int attrlen; 699 700 memset(&fib_cfg, 0, sizeof(fib_cfg)); 701 702 if (!rtnh_ok(rtnh, remaining)) { 703 NL_SET_ERR_MSG(extack, 704 "Invalid nexthop configuration - extra data after nexthop"); 705 return -EINVAL; 706 } 707 708 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 709 NL_SET_ERR_MSG(extack, 710 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 711 return -EINVAL; 712 } 713 714 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 715 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 716 717 attrlen = rtnh_attrlen(rtnh); 718 if (attrlen > 0) { 719 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 720 721 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 722 nlav = nla_find(attrs, attrlen, RTA_VIA); 723 if (nla && nlav) { 724 NL_SET_ERR_MSG(extack, 725 "Nexthop configuration can not contain both GATEWAY and VIA"); 726 return -EINVAL; 727 } 728 if (nla) { 729 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 730 extack); 731 if (ret) 732 goto errout; 733 734 if (fib_cfg.fc_gw4) 735 fib_cfg.fc_gw_family = AF_INET; 736 } else if (nlav) { 737 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 738 if (ret) 739 goto errout; 740 } 741 742 nla = nla_find(attrs, attrlen, RTA_FLOW); 743 if (nla) { 744 if (nla_len(nla) < sizeof(u32)) { 745 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 746 return -EINVAL; 747 } 748 fib_cfg.fc_flow = nla_get_u32(nla); 749 } 750 751 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 752 /* RTA_ENCAP_TYPE length checked in 753 * lwtunnel_valid_encap_type_attr 754 */ 755 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 756 if (nla) 757 fib_cfg.fc_encap_type = nla_get_u16(nla); 758 } 759 760 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 761 rtnh->rtnh_hops + 1, extack); 762 if (ret) 763 goto errout; 764 765 rtnh = rtnh_next(rtnh, &remaining); 766 } endfor_nexthops(fi); 767 768 ret = -EINVAL; 769 nh = fib_info_nh(fi, 0); 770 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 771 NL_SET_ERR_MSG(extack, 772 "Nexthop device index does not match RTA_OIF"); 773 goto errout; 774 } 775 if (cfg->fc_gw_family) { 776 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 777 (cfg->fc_gw_family == AF_INET && 778 nh->fib_nh_gw4 != cfg->fc_gw4) || 779 (cfg->fc_gw_family == AF_INET6 && 780 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 781 NL_SET_ERR_MSG(extack, 782 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 783 goto errout; 784 } 785 } 786 #ifdef CONFIG_IP_ROUTE_CLASSID 787 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 788 NL_SET_ERR_MSG(extack, 789 "Nexthop class id does not match RTA_FLOW"); 790 goto errout; 791 } 792 #endif 793 ret = 0; 794 errout: 795 return ret; 796 } 797 798 /* only called when fib_nh is integrated into fib_info */ 799 static void fib_rebalance(struct fib_info *fi) 800 { 801 int total; 802 int w; 803 804 if (fib_info_num_path(fi) < 2) 805 return; 806 807 total = 0; 808 for_nexthops(fi) { 809 if (nh->fib_nh_flags & RTNH_F_DEAD) 810 continue; 811 812 if (ip_ignore_linkdown(nh->fib_nh_dev) && 813 nh->fib_nh_flags & RTNH_F_LINKDOWN) 814 continue; 815 816 total += nh->fib_nh_weight; 817 } endfor_nexthops(fi); 818 819 w = 0; 820 change_nexthops(fi) { 821 int upper_bound; 822 823 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 824 upper_bound = -1; 825 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 826 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 827 upper_bound = -1; 828 } else { 829 w += nexthop_nh->fib_nh_weight; 830 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 831 total) - 1; 832 } 833 834 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 835 } endfor_nexthops(fi); 836 } 837 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 838 839 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 840 int remaining, struct fib_config *cfg, 841 struct netlink_ext_ack *extack) 842 { 843 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 844 845 return -EINVAL; 846 } 847 848 #define fib_rebalance(fi) do { } while (0) 849 850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 851 852 static int fib_encap_match(struct net *net, u16 encap_type, 853 struct nlattr *encap, 854 const struct fib_nh *nh, 855 const struct fib_config *cfg, 856 struct netlink_ext_ack *extack) 857 { 858 struct lwtunnel_state *lwtstate; 859 int ret, result = 0; 860 861 if (encap_type == LWTUNNEL_ENCAP_NONE) 862 return 0; 863 864 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 865 cfg, &lwtstate, extack); 866 if (!ret) { 867 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 868 lwtstate_free(lwtstate); 869 } 870 871 return result; 872 } 873 874 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 875 struct netlink_ext_ack *extack) 876 { 877 #ifdef CONFIG_IP_ROUTE_MULTIPATH 878 struct rtnexthop *rtnh; 879 int remaining; 880 #endif 881 882 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 883 return 1; 884 885 if (cfg->fc_nh_id) { 886 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 887 return 0; 888 return 1; 889 } 890 891 if (cfg->fc_oif || cfg->fc_gw_family) { 892 struct fib_nh *nh; 893 894 /* cannot match on nexthop object attributes */ 895 if (fi->nh) 896 return 1; 897 898 nh = fib_info_nh(fi, 0); 899 if (cfg->fc_encap) { 900 if (fib_encap_match(net, cfg->fc_encap_type, 901 cfg->fc_encap, nh, cfg, extack)) 902 return 1; 903 } 904 #ifdef CONFIG_IP_ROUTE_CLASSID 905 if (cfg->fc_flow && 906 cfg->fc_flow != nh->nh_tclassid) 907 return 1; 908 #endif 909 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 910 (cfg->fc_gw_family && 911 cfg->fc_gw_family != nh->fib_nh_gw_family)) 912 return 1; 913 914 if (cfg->fc_gw_family == AF_INET && 915 cfg->fc_gw4 != nh->fib_nh_gw4) 916 return 1; 917 918 if (cfg->fc_gw_family == AF_INET6 && 919 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 920 return 1; 921 922 return 0; 923 } 924 925 #ifdef CONFIG_IP_ROUTE_MULTIPATH 926 if (!cfg->fc_mp) 927 return 0; 928 929 rtnh = cfg->fc_mp; 930 remaining = cfg->fc_mp_len; 931 932 for_nexthops(fi) { 933 int attrlen; 934 935 if (!rtnh_ok(rtnh, remaining)) 936 return -EINVAL; 937 938 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 939 return 1; 940 941 attrlen = rtnh_attrlen(rtnh); 942 if (attrlen > 0) { 943 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 944 int err; 945 946 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 947 nlav = nla_find(attrs, attrlen, RTA_VIA); 948 if (nla && nlav) { 949 NL_SET_ERR_MSG(extack, 950 "Nexthop configuration can not contain both GATEWAY and VIA"); 951 return -EINVAL; 952 } 953 954 if (nla) { 955 __be32 gw; 956 957 err = fib_gw_from_attr(&gw, nla, extack); 958 if (err) 959 return err; 960 961 if (nh->fib_nh_gw_family != AF_INET || 962 gw != nh->fib_nh_gw4) 963 return 1; 964 } else if (nlav) { 965 struct fib_config cfg2; 966 967 err = fib_gw_from_via(&cfg2, nlav, extack); 968 if (err) 969 return err; 970 971 switch (nh->fib_nh_gw_family) { 972 case AF_INET: 973 if (cfg2.fc_gw_family != AF_INET || 974 cfg2.fc_gw4 != nh->fib_nh_gw4) 975 return 1; 976 break; 977 case AF_INET6: 978 if (cfg2.fc_gw_family != AF_INET6 || 979 ipv6_addr_cmp(&cfg2.fc_gw6, 980 &nh->fib_nh_gw6)) 981 return 1; 982 break; 983 } 984 } 985 986 #ifdef CONFIG_IP_ROUTE_CLASSID 987 nla = nla_find(attrs, attrlen, RTA_FLOW); 988 if (nla) { 989 if (nla_len(nla) < sizeof(u32)) { 990 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 991 return -EINVAL; 992 } 993 if (nla_get_u32(nla) != nh->nh_tclassid) 994 return 1; 995 } 996 #endif 997 } 998 999 rtnh = rtnh_next(rtnh, &remaining); 1000 } endfor_nexthops(fi); 1001 #endif 1002 return 0; 1003 } 1004 1005 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1006 { 1007 struct nlattr *nla; 1008 int remaining; 1009 1010 if (!cfg->fc_mx) 1011 return true; 1012 1013 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1014 int type = nla_type(nla); 1015 u32 fi_val, val; 1016 1017 if (!type) 1018 continue; 1019 if (type > RTAX_MAX) 1020 return false; 1021 1022 if (type == RTAX_CC_ALGO) { 1023 char tmp[TCP_CA_NAME_MAX]; 1024 bool ecn_ca = false; 1025 1026 nla_strscpy(tmp, nla, sizeof(tmp)); 1027 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1028 } else { 1029 if (nla_len(nla) != sizeof(u32)) 1030 return false; 1031 val = nla_get_u32(nla); 1032 } 1033 1034 fi_val = fi->fib_metrics->metrics[type - 1]; 1035 if (type == RTAX_FEATURES) 1036 fi_val &= ~DST_FEATURE_ECN_CA; 1037 1038 if (fi_val != val) 1039 return false; 1040 } 1041 1042 return true; 1043 } 1044 1045 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1046 u32 table, struct netlink_ext_ack *extack) 1047 { 1048 struct fib6_config cfg = { 1049 .fc_table = table, 1050 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1051 .fc_ifindex = nh->fib_nh_oif, 1052 .fc_gateway = nh->fib_nh_gw6, 1053 }; 1054 struct fib6_nh fib6_nh = {}; 1055 int err; 1056 1057 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1058 if (!err) { 1059 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1060 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL); 1061 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1062 nh->fib_nh_scope = RT_SCOPE_LINK; 1063 1064 ipv6_stub->fib6_nh_release(&fib6_nh); 1065 } 1066 1067 return err; 1068 } 1069 1070 /* 1071 * Picture 1072 * ------- 1073 * 1074 * Semantics of nexthop is very messy by historical reasons. 1075 * We have to take into account, that: 1076 * a) gateway can be actually local interface address, 1077 * so that gatewayed route is direct. 1078 * b) gateway must be on-link address, possibly 1079 * described not by an ifaddr, but also by a direct route. 1080 * c) If both gateway and interface are specified, they should not 1081 * contradict. 1082 * d) If we use tunnel routes, gateway could be not on-link. 1083 * 1084 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1085 * results in pretty ugly and hairy code with obscure logic. 1086 * 1087 * I chose to generalized it instead, so that the size 1088 * of code does not increase practically, but it becomes 1089 * much more general. 1090 * Every prefix is assigned a "scope" value: "host" is local address, 1091 * "link" is direct route, 1092 * [ ... "site" ... "interior" ... ] 1093 * and "universe" is true gateway route with global meaning. 1094 * 1095 * Every prefix refers to a set of "nexthop"s (gw, oif), 1096 * where gw must have narrower scope. This recursion stops 1097 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1098 * which means that gw is forced to be on link. 1099 * 1100 * Code is still hairy, but now it is apparently logically 1101 * consistent and very flexible. F.e. as by-product it allows 1102 * to co-exists in peace independent exterior and interior 1103 * routing processes. 1104 * 1105 * Normally it looks as following. 1106 * 1107 * {universe prefix} -> (gw, oif) [scope link] 1108 * | 1109 * |-> {link prefix} -> (gw, oif) [scope local] 1110 * | 1111 * |-> {local prefix} (terminal node) 1112 */ 1113 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1114 u8 scope, struct netlink_ext_ack *extack) 1115 { 1116 struct net_device *dev; 1117 struct fib_result res; 1118 int err = 0; 1119 1120 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1121 unsigned int addr_type; 1122 1123 if (scope >= RT_SCOPE_LINK) { 1124 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1125 return -EINVAL; 1126 } 1127 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1128 if (!dev) { 1129 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1130 return -ENODEV; 1131 } 1132 if (!(dev->flags & IFF_UP)) { 1133 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1134 return -ENETDOWN; 1135 } 1136 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1137 if (addr_type != RTN_UNICAST) { 1138 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1139 return -EINVAL; 1140 } 1141 if (!netif_carrier_ok(dev)) 1142 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1143 nh->fib_nh_dev = dev; 1144 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1145 nh->fib_nh_scope = RT_SCOPE_LINK; 1146 return 0; 1147 } 1148 rcu_read_lock(); 1149 { 1150 struct fib_table *tbl = NULL; 1151 struct flowi4 fl4 = { 1152 .daddr = nh->fib_nh_gw4, 1153 .flowi4_scope = scope + 1, 1154 .flowi4_oif = nh->fib_nh_oif, 1155 .flowi4_iif = LOOPBACK_IFINDEX, 1156 }; 1157 1158 /* It is not necessary, but requires a bit of thinking */ 1159 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1160 fl4.flowi4_scope = RT_SCOPE_LINK; 1161 1162 if (table && table != RT_TABLE_MAIN) 1163 tbl = fib_get_table(net, table); 1164 1165 if (tbl) 1166 err = fib_table_lookup(tbl, &fl4, &res, 1167 FIB_LOOKUP_IGNORE_LINKSTATE | 1168 FIB_LOOKUP_NOREF); 1169 1170 /* on error or if no table given do full lookup. This 1171 * is needed for example when nexthops are in the local 1172 * table rather than the given table 1173 */ 1174 if (!tbl || err) { 1175 err = fib_lookup(net, &fl4, &res, 1176 FIB_LOOKUP_IGNORE_LINKSTATE); 1177 } 1178 1179 if (err) { 1180 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1181 goto out; 1182 } 1183 } 1184 1185 err = -EINVAL; 1186 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1187 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1188 goto out; 1189 } 1190 nh->fib_nh_scope = res.scope; 1191 nh->fib_nh_oif = FIB_RES_OIF(res); 1192 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1193 if (!dev) { 1194 NL_SET_ERR_MSG(extack, 1195 "No egress device for nexthop gateway"); 1196 goto out; 1197 } 1198 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1199 if (!netif_carrier_ok(dev)) 1200 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1201 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1202 out: 1203 rcu_read_unlock(); 1204 return err; 1205 } 1206 1207 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1208 struct netlink_ext_ack *extack) 1209 { 1210 struct in_device *in_dev; 1211 int err; 1212 1213 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1214 NL_SET_ERR_MSG(extack, 1215 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1216 return -EINVAL; 1217 } 1218 1219 rcu_read_lock(); 1220 1221 err = -ENODEV; 1222 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1223 if (!in_dev) 1224 goto out; 1225 err = -ENETDOWN; 1226 if (!(in_dev->dev->flags & IFF_UP)) { 1227 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1228 goto out; 1229 } 1230 1231 nh->fib_nh_dev = in_dev->dev; 1232 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1233 nh->fib_nh_scope = RT_SCOPE_HOST; 1234 if (!netif_carrier_ok(nh->fib_nh_dev)) 1235 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1236 err = 0; 1237 out: 1238 rcu_read_unlock(); 1239 return err; 1240 } 1241 1242 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1243 struct netlink_ext_ack *extack) 1244 { 1245 int err; 1246 1247 if (nh->fib_nh_gw_family == AF_INET) 1248 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1249 else if (nh->fib_nh_gw_family == AF_INET6) 1250 err = fib_check_nh_v6_gw(net, nh, table, extack); 1251 else 1252 err = fib_check_nh_nongw(net, nh, extack); 1253 1254 return err; 1255 } 1256 1257 static struct hlist_head * 1258 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1259 { 1260 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1261 fib_info_hash_bits); 1262 1263 return &fib_info_laddrhash[slot]; 1264 } 1265 1266 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1267 struct hlist_head *new_laddrhash, 1268 unsigned int new_size) 1269 { 1270 struct hlist_head *old_info_hash, *old_laddrhash; 1271 unsigned int old_size = fib_info_hash_size; 1272 unsigned int i; 1273 1274 spin_lock_bh(&fib_info_lock); 1275 old_info_hash = fib_info_hash; 1276 old_laddrhash = fib_info_laddrhash; 1277 fib_info_hash_size = new_size; 1278 fib_info_hash_bits = ilog2(new_size); 1279 1280 for (i = 0; i < old_size; i++) { 1281 struct hlist_head *head = &fib_info_hash[i]; 1282 struct hlist_node *n; 1283 struct fib_info *fi; 1284 1285 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1286 struct hlist_head *dest; 1287 unsigned int new_hash; 1288 1289 new_hash = fib_info_hashfn(fi); 1290 dest = &new_info_hash[new_hash]; 1291 hlist_add_head(&fi->fib_hash, dest); 1292 } 1293 } 1294 fib_info_hash = new_info_hash; 1295 1296 fib_info_laddrhash = new_laddrhash; 1297 for (i = 0; i < old_size; i++) { 1298 struct hlist_head *lhead = &old_laddrhash[i]; 1299 struct hlist_node *n; 1300 struct fib_info *fi; 1301 1302 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1303 struct hlist_head *ldest; 1304 1305 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1306 fi->fib_prefsrc); 1307 hlist_add_head(&fi->fib_lhash, ldest); 1308 } 1309 } 1310 1311 spin_unlock_bh(&fib_info_lock); 1312 1313 kvfree(old_info_hash); 1314 kvfree(old_laddrhash); 1315 } 1316 1317 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1318 unsigned char scope) 1319 { 1320 struct fib_nh *nh; 1321 1322 if (nhc->nhc_family != AF_INET) 1323 return inet_select_addr(nhc->nhc_dev, 0, scope); 1324 1325 nh = container_of(nhc, struct fib_nh, nh_common); 1326 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1327 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1328 1329 return nh->nh_saddr; 1330 } 1331 1332 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1333 { 1334 struct fib_nh_common *nhc = res->nhc; 1335 1336 if (res->fi->fib_prefsrc) 1337 return res->fi->fib_prefsrc; 1338 1339 if (nhc->nhc_family == AF_INET) { 1340 struct fib_nh *nh; 1341 1342 nh = container_of(nhc, struct fib_nh, nh_common); 1343 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1344 return nh->nh_saddr; 1345 } 1346 1347 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1348 } 1349 1350 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1351 { 1352 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1353 fib_prefsrc != cfg->fc_dst) { 1354 u32 tb_id = cfg->fc_table; 1355 int rc; 1356 1357 if (tb_id == RT_TABLE_MAIN) 1358 tb_id = RT_TABLE_LOCAL; 1359 1360 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1361 fib_prefsrc, tb_id); 1362 1363 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1364 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1365 fib_prefsrc, RT_TABLE_LOCAL); 1366 } 1367 1368 if (rc != RTN_LOCAL) 1369 return false; 1370 } 1371 return true; 1372 } 1373 1374 struct fib_info *fib_create_info(struct fib_config *cfg, 1375 struct netlink_ext_ack *extack) 1376 { 1377 int err; 1378 struct fib_info *fi = NULL; 1379 struct nexthop *nh = NULL; 1380 struct fib_info *ofi; 1381 int nhs = 1; 1382 struct net *net = cfg->fc_nlinfo.nl_net; 1383 1384 if (cfg->fc_type > RTN_MAX) 1385 goto err_inval; 1386 1387 /* Fast check to catch the most weird cases */ 1388 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1389 NL_SET_ERR_MSG(extack, "Invalid scope"); 1390 goto err_inval; 1391 } 1392 1393 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1394 NL_SET_ERR_MSG(extack, 1395 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1396 goto err_inval; 1397 } 1398 1399 if (cfg->fc_nh_id) { 1400 if (!cfg->fc_mx) { 1401 fi = fib_find_info_nh(net, cfg); 1402 if (fi) { 1403 refcount_inc(&fi->fib_treeref); 1404 return fi; 1405 } 1406 } 1407 1408 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1409 if (!nh) { 1410 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1411 goto err_inval; 1412 } 1413 nhs = 0; 1414 } 1415 1416 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1417 if (cfg->fc_mp) { 1418 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1419 if (nhs == 0) 1420 goto err_inval; 1421 } 1422 #endif 1423 1424 err = -ENOBUFS; 1425 1426 /* Paired with WRITE_ONCE() in fib_release_info() */ 1427 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1428 unsigned int new_size = fib_info_hash_size << 1; 1429 struct hlist_head *new_info_hash; 1430 struct hlist_head *new_laddrhash; 1431 size_t bytes; 1432 1433 if (!new_size) 1434 new_size = 16; 1435 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1436 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1437 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1438 if (!new_info_hash || !new_laddrhash) { 1439 kvfree(new_info_hash); 1440 kvfree(new_laddrhash); 1441 } else { 1442 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1443 } 1444 if (!fib_info_hash_size) 1445 goto failure; 1446 } 1447 1448 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1449 if (!fi) 1450 goto failure; 1451 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1452 cfg->fc_mx_len, extack); 1453 if (IS_ERR(fi->fib_metrics)) { 1454 err = PTR_ERR(fi->fib_metrics); 1455 kfree(fi); 1456 return ERR_PTR(err); 1457 } 1458 1459 fi->fib_net = net; 1460 fi->fib_protocol = cfg->fc_protocol; 1461 fi->fib_scope = cfg->fc_scope; 1462 fi->fib_flags = cfg->fc_flags; 1463 fi->fib_priority = cfg->fc_priority; 1464 fi->fib_prefsrc = cfg->fc_prefsrc; 1465 fi->fib_type = cfg->fc_type; 1466 fi->fib_tb_id = cfg->fc_table; 1467 1468 fi->fib_nhs = nhs; 1469 if (nh) { 1470 if (!nexthop_get(nh)) { 1471 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1472 err = -EINVAL; 1473 } else { 1474 err = 0; 1475 fi->nh = nh; 1476 } 1477 } else { 1478 change_nexthops(fi) { 1479 nexthop_nh->nh_parent = fi; 1480 } endfor_nexthops(fi) 1481 1482 if (cfg->fc_mp) 1483 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1484 extack); 1485 else 1486 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1487 } 1488 1489 if (err != 0) 1490 goto failure; 1491 1492 if (fib_props[cfg->fc_type].error) { 1493 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1494 NL_SET_ERR_MSG(extack, 1495 "Gateway, device and multipath can not be specified for this route type"); 1496 goto err_inval; 1497 } 1498 goto link_it; 1499 } else { 1500 switch (cfg->fc_type) { 1501 case RTN_UNICAST: 1502 case RTN_LOCAL: 1503 case RTN_BROADCAST: 1504 case RTN_ANYCAST: 1505 case RTN_MULTICAST: 1506 break; 1507 default: 1508 NL_SET_ERR_MSG(extack, "Invalid route type"); 1509 goto err_inval; 1510 } 1511 } 1512 1513 if (cfg->fc_scope > RT_SCOPE_HOST) { 1514 NL_SET_ERR_MSG(extack, "Invalid scope"); 1515 goto err_inval; 1516 } 1517 1518 if (fi->nh) { 1519 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1520 if (err) 1521 goto failure; 1522 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1523 struct fib_nh *nh = fi->fib_nh; 1524 1525 /* Local address is added. */ 1526 if (nhs != 1) { 1527 NL_SET_ERR_MSG(extack, 1528 "Route with host scope can not have multiple nexthops"); 1529 goto err_inval; 1530 } 1531 if (nh->fib_nh_gw_family) { 1532 NL_SET_ERR_MSG(extack, 1533 "Route with host scope can not have a gateway"); 1534 goto err_inval; 1535 } 1536 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1537 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1538 err = -ENODEV; 1539 if (!nh->fib_nh_dev) 1540 goto failure; 1541 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1542 GFP_KERNEL); 1543 } else { 1544 int linkdown = 0; 1545 1546 change_nexthops(fi) { 1547 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1548 cfg->fc_table, cfg->fc_scope, 1549 extack); 1550 if (err != 0) 1551 goto failure; 1552 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1553 linkdown++; 1554 } endfor_nexthops(fi) 1555 if (linkdown == fi->fib_nhs) 1556 fi->fib_flags |= RTNH_F_LINKDOWN; 1557 } 1558 1559 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1560 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1561 goto err_inval; 1562 } 1563 1564 if (!fi->nh) { 1565 change_nexthops(fi) { 1566 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1567 fi->fib_scope); 1568 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1569 fi->fib_nh_is_v6 = true; 1570 } endfor_nexthops(fi) 1571 1572 fib_rebalance(fi); 1573 } 1574 1575 link_it: 1576 ofi = fib_find_info(fi); 1577 if (ofi) { 1578 fi->fib_dead = 1; 1579 free_fib_info(fi); 1580 refcount_inc(&ofi->fib_treeref); 1581 return ofi; 1582 } 1583 1584 refcount_set(&fi->fib_treeref, 1); 1585 refcount_set(&fi->fib_clntref, 1); 1586 spin_lock_bh(&fib_info_lock); 1587 fib_info_cnt++; 1588 hlist_add_head(&fi->fib_hash, 1589 &fib_info_hash[fib_info_hashfn(fi)]); 1590 if (fi->fib_prefsrc) { 1591 struct hlist_head *head; 1592 1593 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1594 hlist_add_head(&fi->fib_lhash, head); 1595 } 1596 if (fi->nh) { 1597 list_add(&fi->nh_list, &nh->fi_list); 1598 } else { 1599 change_nexthops(fi) { 1600 struct hlist_head *head; 1601 1602 if (!nexthop_nh->fib_nh_dev) 1603 continue; 1604 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1605 hlist_add_head(&nexthop_nh->nh_hash, head); 1606 } endfor_nexthops(fi) 1607 } 1608 spin_unlock_bh(&fib_info_lock); 1609 return fi; 1610 1611 err_inval: 1612 err = -EINVAL; 1613 1614 failure: 1615 if (fi) { 1616 fi->fib_dead = 1; 1617 free_fib_info(fi); 1618 } 1619 1620 return ERR_PTR(err); 1621 } 1622 1623 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1624 u8 rt_family, unsigned char *flags, bool skip_oif) 1625 { 1626 if (nhc->nhc_flags & RTNH_F_DEAD) 1627 *flags |= RTNH_F_DEAD; 1628 1629 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1630 *flags |= RTNH_F_LINKDOWN; 1631 1632 rcu_read_lock(); 1633 switch (nhc->nhc_family) { 1634 case AF_INET: 1635 if (ip_ignore_linkdown(nhc->nhc_dev)) 1636 *flags |= RTNH_F_DEAD; 1637 break; 1638 case AF_INET6: 1639 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1640 *flags |= RTNH_F_DEAD; 1641 break; 1642 } 1643 rcu_read_unlock(); 1644 } 1645 1646 switch (nhc->nhc_gw_family) { 1647 case AF_INET: 1648 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1649 goto nla_put_failure; 1650 break; 1651 case AF_INET6: 1652 /* if gateway family does not match nexthop family 1653 * gateway is encoded as RTA_VIA 1654 */ 1655 if (rt_family != nhc->nhc_gw_family) { 1656 int alen = sizeof(struct in6_addr); 1657 struct nlattr *nla; 1658 struct rtvia *via; 1659 1660 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1661 if (!nla) 1662 goto nla_put_failure; 1663 1664 via = nla_data(nla); 1665 via->rtvia_family = AF_INET6; 1666 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1667 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1668 &nhc->nhc_gw.ipv6) < 0) { 1669 goto nla_put_failure; 1670 } 1671 break; 1672 } 1673 1674 *flags |= (nhc->nhc_flags & 1675 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1676 1677 if (!skip_oif && nhc->nhc_dev && 1678 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1679 goto nla_put_failure; 1680 1681 if (nhc->nhc_lwtstate && 1682 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1683 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1684 goto nla_put_failure; 1685 1686 return 0; 1687 1688 nla_put_failure: 1689 return -EMSGSIZE; 1690 } 1691 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1692 1693 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1694 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1695 int nh_weight, u8 rt_family, u32 nh_tclassid) 1696 { 1697 const struct net_device *dev = nhc->nhc_dev; 1698 struct rtnexthop *rtnh; 1699 unsigned char flags = 0; 1700 1701 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1702 if (!rtnh) 1703 goto nla_put_failure; 1704 1705 rtnh->rtnh_hops = nh_weight - 1; 1706 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1707 1708 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1709 goto nla_put_failure; 1710 1711 rtnh->rtnh_flags = flags; 1712 1713 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1714 goto nla_put_failure; 1715 1716 /* length of rtnetlink header + attributes */ 1717 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1718 1719 return 0; 1720 1721 nla_put_failure: 1722 return -EMSGSIZE; 1723 } 1724 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1725 #endif 1726 1727 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1728 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1729 { 1730 struct nlattr *mp; 1731 1732 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1733 if (!mp) 1734 goto nla_put_failure; 1735 1736 if (unlikely(fi->nh)) { 1737 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1738 goto nla_put_failure; 1739 goto mp_end; 1740 } 1741 1742 for_nexthops(fi) { 1743 u32 nh_tclassid = 0; 1744 #ifdef CONFIG_IP_ROUTE_CLASSID 1745 nh_tclassid = nh->nh_tclassid; 1746 #endif 1747 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1748 AF_INET, nh_tclassid) < 0) 1749 goto nla_put_failure; 1750 } endfor_nexthops(fi); 1751 1752 mp_end: 1753 nla_nest_end(skb, mp); 1754 1755 return 0; 1756 1757 nla_put_failure: 1758 return -EMSGSIZE; 1759 } 1760 #else 1761 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1762 { 1763 return 0; 1764 } 1765 #endif 1766 1767 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1768 const struct fib_rt_info *fri, unsigned int flags) 1769 { 1770 unsigned int nhs = fib_info_num_path(fri->fi); 1771 struct fib_info *fi = fri->fi; 1772 u32 tb_id = fri->tb_id; 1773 struct nlmsghdr *nlh; 1774 struct rtmsg *rtm; 1775 1776 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1777 if (!nlh) 1778 return -EMSGSIZE; 1779 1780 rtm = nlmsg_data(nlh); 1781 rtm->rtm_family = AF_INET; 1782 rtm->rtm_dst_len = fri->dst_len; 1783 rtm->rtm_src_len = 0; 1784 rtm->rtm_tos = fri->tos; 1785 if (tb_id < 256) 1786 rtm->rtm_table = tb_id; 1787 else 1788 rtm->rtm_table = RT_TABLE_COMPAT; 1789 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1790 goto nla_put_failure; 1791 rtm->rtm_type = fri->type; 1792 rtm->rtm_flags = fi->fib_flags; 1793 rtm->rtm_scope = fi->fib_scope; 1794 rtm->rtm_protocol = fi->fib_protocol; 1795 1796 if (rtm->rtm_dst_len && 1797 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1798 goto nla_put_failure; 1799 if (fi->fib_priority && 1800 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1801 goto nla_put_failure; 1802 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1803 goto nla_put_failure; 1804 1805 if (fi->fib_prefsrc && 1806 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1807 goto nla_put_failure; 1808 1809 if (fi->nh) { 1810 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1811 goto nla_put_failure; 1812 if (nexthop_is_blackhole(fi->nh)) 1813 rtm->rtm_type = RTN_BLACKHOLE; 1814 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode) 1815 goto offload; 1816 } 1817 1818 if (nhs == 1) { 1819 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1820 unsigned char flags = 0; 1821 1822 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1823 goto nla_put_failure; 1824 1825 rtm->rtm_flags = flags; 1826 #ifdef CONFIG_IP_ROUTE_CLASSID 1827 if (nhc->nhc_family == AF_INET) { 1828 struct fib_nh *nh; 1829 1830 nh = container_of(nhc, struct fib_nh, nh_common); 1831 if (nh->nh_tclassid && 1832 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1833 goto nla_put_failure; 1834 } 1835 #endif 1836 } else { 1837 if (fib_add_multipath(skb, fi) < 0) 1838 goto nla_put_failure; 1839 } 1840 1841 offload: 1842 if (fri->offload) 1843 rtm->rtm_flags |= RTM_F_OFFLOAD; 1844 if (fri->trap) 1845 rtm->rtm_flags |= RTM_F_TRAP; 1846 if (fri->offload_failed) 1847 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1848 1849 nlmsg_end(skb, nlh); 1850 return 0; 1851 1852 nla_put_failure: 1853 nlmsg_cancel(skb, nlh); 1854 return -EMSGSIZE; 1855 } 1856 1857 /* 1858 * Update FIB if: 1859 * - local address disappeared -> we must delete all the entries 1860 * referring to it. 1861 * - device went down -> we must shutdown all nexthops going via it. 1862 */ 1863 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1864 { 1865 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1866 struct net *net = dev_net(dev); 1867 struct hlist_head *head; 1868 struct fib_info *fi; 1869 int ret = 0; 1870 1871 if (!fib_info_laddrhash || local == 0) 1872 return 0; 1873 1874 head = fib_info_laddrhash_bucket(net, local); 1875 hlist_for_each_entry(fi, head, fib_lhash) { 1876 if (!net_eq(fi->fib_net, net) || 1877 fi->fib_tb_id != tb_id) 1878 continue; 1879 if (fi->fib_prefsrc == local) { 1880 fi->fib_flags |= RTNH_F_DEAD; 1881 ret++; 1882 } 1883 } 1884 return ret; 1885 } 1886 1887 static int call_fib_nh_notifiers(struct fib_nh *nh, 1888 enum fib_event_type event_type) 1889 { 1890 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1891 struct fib_nh_notifier_info info = { 1892 .fib_nh = nh, 1893 }; 1894 1895 switch (event_type) { 1896 case FIB_EVENT_NH_ADD: 1897 if (nh->fib_nh_flags & RTNH_F_DEAD) 1898 break; 1899 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1900 break; 1901 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1902 &info.info); 1903 case FIB_EVENT_NH_DEL: 1904 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1905 (nh->fib_nh_flags & RTNH_F_DEAD)) 1906 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1907 event_type, &info.info); 1908 break; 1909 default: 1910 break; 1911 } 1912 1913 return NOTIFY_DONE; 1914 } 1915 1916 /* Update the PMTU of exceptions when: 1917 * - the new MTU of the first hop becomes smaller than the PMTU 1918 * - the old MTU was the same as the PMTU, and it limited discovery of 1919 * larger MTUs on the path. With that limit raised, we can now 1920 * discover larger MTUs 1921 * A special case is locked exceptions, for which the PMTU is smaller 1922 * than the minimal accepted PMTU: 1923 * - if the new MTU is greater than the PMTU, don't make any change 1924 * - otherwise, unlock and set PMTU 1925 */ 1926 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1927 { 1928 struct fnhe_hash_bucket *bucket; 1929 int i; 1930 1931 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1932 if (!bucket) 1933 return; 1934 1935 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1936 struct fib_nh_exception *fnhe; 1937 1938 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1939 fnhe; 1940 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1941 if (fnhe->fnhe_mtu_locked) { 1942 if (new <= fnhe->fnhe_pmtu) { 1943 fnhe->fnhe_pmtu = new; 1944 fnhe->fnhe_mtu_locked = false; 1945 } 1946 } else if (new < fnhe->fnhe_pmtu || 1947 orig == fnhe->fnhe_pmtu) { 1948 fnhe->fnhe_pmtu = new; 1949 } 1950 } 1951 } 1952 } 1953 1954 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1955 { 1956 struct hlist_head *head = fib_info_devhash_bucket(dev); 1957 struct fib_nh *nh; 1958 1959 hlist_for_each_entry(nh, head, nh_hash) { 1960 if (nh->fib_nh_dev == dev) 1961 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1962 } 1963 } 1964 1965 /* Event force Flags Description 1966 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1967 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1968 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1969 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1970 * 1971 * only used when fib_nh is built into fib_info 1972 */ 1973 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1974 { 1975 struct hlist_head *head = fib_info_devhash_bucket(dev); 1976 struct fib_info *prev_fi = NULL; 1977 int scope = RT_SCOPE_NOWHERE; 1978 struct fib_nh *nh; 1979 int ret = 0; 1980 1981 if (force) 1982 scope = -1; 1983 1984 hlist_for_each_entry(nh, head, nh_hash) { 1985 struct fib_info *fi = nh->nh_parent; 1986 int dead; 1987 1988 BUG_ON(!fi->fib_nhs); 1989 if (nh->fib_nh_dev != dev || fi == prev_fi) 1990 continue; 1991 prev_fi = fi; 1992 dead = 0; 1993 change_nexthops(fi) { 1994 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1995 dead++; 1996 else if (nexthop_nh->fib_nh_dev == dev && 1997 nexthop_nh->fib_nh_scope != scope) { 1998 switch (event) { 1999 case NETDEV_DOWN: 2000 case NETDEV_UNREGISTER: 2001 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2002 fallthrough; 2003 case NETDEV_CHANGE: 2004 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2005 break; 2006 } 2007 call_fib_nh_notifiers(nexthop_nh, 2008 FIB_EVENT_NH_DEL); 2009 dead++; 2010 } 2011 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2012 if (event == NETDEV_UNREGISTER && 2013 nexthop_nh->fib_nh_dev == dev) { 2014 dead = fi->fib_nhs; 2015 break; 2016 } 2017 #endif 2018 } endfor_nexthops(fi) 2019 if (dead == fi->fib_nhs) { 2020 switch (event) { 2021 case NETDEV_DOWN: 2022 case NETDEV_UNREGISTER: 2023 fi->fib_flags |= RTNH_F_DEAD; 2024 fallthrough; 2025 case NETDEV_CHANGE: 2026 fi->fib_flags |= RTNH_F_LINKDOWN; 2027 break; 2028 } 2029 ret++; 2030 } 2031 2032 fib_rebalance(fi); 2033 } 2034 2035 return ret; 2036 } 2037 2038 /* Must be invoked inside of an RCU protected region. */ 2039 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2040 { 2041 struct fib_info *fi = NULL, *last_resort = NULL; 2042 struct hlist_head *fa_head = res->fa_head; 2043 struct fib_table *tb = res->table; 2044 u8 slen = 32 - res->prefixlen; 2045 int order = -1, last_idx = -1; 2046 struct fib_alias *fa, *fa1 = NULL; 2047 u32 last_prio = res->fi->fib_priority; 2048 dscp_t last_dscp = 0; 2049 2050 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2051 struct fib_info *next_fi = fa->fa_info; 2052 struct fib_nh_common *nhc; 2053 2054 if (fa->fa_slen != slen) 2055 continue; 2056 if (fa->fa_dscp && 2057 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos)) 2058 continue; 2059 if (fa->tb_id != tb->tb_id) 2060 continue; 2061 if (next_fi->fib_priority > last_prio && 2062 fa->fa_dscp == last_dscp) { 2063 if (last_dscp) 2064 continue; 2065 break; 2066 } 2067 if (next_fi->fib_flags & RTNH_F_DEAD) 2068 continue; 2069 last_dscp = fa->fa_dscp; 2070 last_prio = next_fi->fib_priority; 2071 2072 if (next_fi->fib_scope != res->scope || 2073 fa->fa_type != RTN_UNICAST) 2074 continue; 2075 2076 nhc = fib_info_nhc(next_fi, 0); 2077 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2078 continue; 2079 2080 fib_alias_accessed(fa); 2081 2082 if (!fi) { 2083 if (next_fi != res->fi) 2084 break; 2085 fa1 = fa; 2086 } else if (!fib_detect_death(fi, order, &last_resort, 2087 &last_idx, fa1->fa_default)) { 2088 fib_result_assign(res, fi); 2089 fa1->fa_default = order; 2090 goto out; 2091 } 2092 fi = next_fi; 2093 order++; 2094 } 2095 2096 if (order <= 0 || !fi) { 2097 if (fa1) 2098 fa1->fa_default = -1; 2099 goto out; 2100 } 2101 2102 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2103 fa1->fa_default)) { 2104 fib_result_assign(res, fi); 2105 fa1->fa_default = order; 2106 goto out; 2107 } 2108 2109 if (last_idx >= 0) 2110 fib_result_assign(res, last_resort); 2111 fa1->fa_default = last_idx; 2112 out: 2113 return; 2114 } 2115 2116 /* 2117 * Dead device goes up. We wake up dead nexthops. 2118 * It takes sense only on multipath routes. 2119 * 2120 * only used when fib_nh is built into fib_info 2121 */ 2122 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2123 { 2124 struct fib_info *prev_fi; 2125 struct hlist_head *head; 2126 struct fib_nh *nh; 2127 int ret; 2128 2129 if (!(dev->flags & IFF_UP)) 2130 return 0; 2131 2132 if (nh_flags & RTNH_F_DEAD) { 2133 unsigned int flags = dev_get_flags(dev); 2134 2135 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2136 nh_flags |= RTNH_F_LINKDOWN; 2137 } 2138 2139 prev_fi = NULL; 2140 head = fib_info_devhash_bucket(dev); 2141 ret = 0; 2142 2143 hlist_for_each_entry(nh, head, nh_hash) { 2144 struct fib_info *fi = nh->nh_parent; 2145 int alive; 2146 2147 BUG_ON(!fi->fib_nhs); 2148 if (nh->fib_nh_dev != dev || fi == prev_fi) 2149 continue; 2150 2151 prev_fi = fi; 2152 alive = 0; 2153 change_nexthops(fi) { 2154 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2155 alive++; 2156 continue; 2157 } 2158 if (!nexthop_nh->fib_nh_dev || 2159 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2160 continue; 2161 if (nexthop_nh->fib_nh_dev != dev || 2162 !__in_dev_get_rtnl(dev)) 2163 continue; 2164 alive++; 2165 nexthop_nh->fib_nh_flags &= ~nh_flags; 2166 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2167 } endfor_nexthops(fi) 2168 2169 if (alive > 0) { 2170 fi->fib_flags &= ~nh_flags; 2171 ret++; 2172 } 2173 2174 fib_rebalance(fi); 2175 } 2176 2177 return ret; 2178 } 2179 2180 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2181 static bool fib_good_nh(const struct fib_nh *nh) 2182 { 2183 int state = NUD_REACHABLE; 2184 2185 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2186 struct neighbour *n; 2187 2188 rcu_read_lock_bh(); 2189 2190 if (likely(nh->fib_nh_gw_family == AF_INET)) 2191 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2192 (__force u32)nh->fib_nh_gw4); 2193 else if (nh->fib_nh_gw_family == AF_INET6) 2194 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2195 &nh->fib_nh_gw6); 2196 else 2197 n = NULL; 2198 if (n) 2199 state = n->nud_state; 2200 2201 rcu_read_unlock_bh(); 2202 } 2203 2204 return !!(state & NUD_VALID); 2205 } 2206 2207 void fib_select_multipath(struct fib_result *res, int hash) 2208 { 2209 struct fib_info *fi = res->fi; 2210 struct net *net = fi->fib_net; 2211 bool first = false; 2212 2213 if (unlikely(res->fi->nh)) { 2214 nexthop_path_fib_result(res, hash); 2215 return; 2216 } 2217 2218 change_nexthops(fi) { 2219 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 2220 if (!fib_good_nh(nexthop_nh)) 2221 continue; 2222 if (!first) { 2223 res->nh_sel = nhsel; 2224 res->nhc = &nexthop_nh->nh_common; 2225 first = true; 2226 } 2227 } 2228 2229 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2230 continue; 2231 2232 res->nh_sel = nhsel; 2233 res->nhc = &nexthop_nh->nh_common; 2234 return; 2235 } endfor_nexthops(fi); 2236 } 2237 #endif 2238 2239 void fib_select_path(struct net *net, struct fib_result *res, 2240 struct flowi4 *fl4, const struct sk_buff *skb) 2241 { 2242 if (fl4->flowi4_oif) 2243 goto check_saddr; 2244 2245 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2246 if (fib_info_num_path(res->fi) > 1) { 2247 int h = fib_multipath_hash(net, fl4, skb, NULL); 2248 2249 fib_select_multipath(res, h); 2250 } 2251 else 2252 #endif 2253 if (!res->prefixlen && 2254 res->table->tb_num_default > 1 && 2255 res->type == RTN_UNICAST) 2256 fib_select_default(fl4, res); 2257 2258 check_saddr: 2259 if (!fl4->saddr) 2260 fl4->saddr = fib_result_prefsrc(net, res); 2261 } 2262