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 = fib_info_nh(fi, 0); 893 894 if (cfg->fc_encap) { 895 if (fib_encap_match(net, cfg->fc_encap_type, 896 cfg->fc_encap, nh, cfg, extack)) 897 return 1; 898 } 899 #ifdef CONFIG_IP_ROUTE_CLASSID 900 if (cfg->fc_flow && 901 cfg->fc_flow != nh->nh_tclassid) 902 return 1; 903 #endif 904 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 905 (cfg->fc_gw_family && 906 cfg->fc_gw_family != nh->fib_nh_gw_family)) 907 return 1; 908 909 if (cfg->fc_gw_family == AF_INET && 910 cfg->fc_gw4 != nh->fib_nh_gw4) 911 return 1; 912 913 if (cfg->fc_gw_family == AF_INET6 && 914 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 915 return 1; 916 917 return 0; 918 } 919 920 #ifdef CONFIG_IP_ROUTE_MULTIPATH 921 if (!cfg->fc_mp) 922 return 0; 923 924 rtnh = cfg->fc_mp; 925 remaining = cfg->fc_mp_len; 926 927 for_nexthops(fi) { 928 int attrlen; 929 930 if (!rtnh_ok(rtnh, remaining)) 931 return -EINVAL; 932 933 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 934 return 1; 935 936 attrlen = rtnh_attrlen(rtnh); 937 if (attrlen > 0) { 938 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 939 int err; 940 941 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 942 nlav = nla_find(attrs, attrlen, RTA_VIA); 943 if (nla && nlav) { 944 NL_SET_ERR_MSG(extack, 945 "Nexthop configuration can not contain both GATEWAY and VIA"); 946 return -EINVAL; 947 } 948 949 if (nla) { 950 __be32 gw; 951 952 err = fib_gw_from_attr(&gw, nla, extack); 953 if (err) 954 return err; 955 956 if (nh->fib_nh_gw_family != AF_INET || 957 gw != nh->fib_nh_gw4) 958 return 1; 959 } else if (nlav) { 960 struct fib_config cfg2; 961 962 err = fib_gw_from_via(&cfg2, nlav, extack); 963 if (err) 964 return err; 965 966 switch (nh->fib_nh_gw_family) { 967 case AF_INET: 968 if (cfg2.fc_gw_family != AF_INET || 969 cfg2.fc_gw4 != nh->fib_nh_gw4) 970 return 1; 971 break; 972 case AF_INET6: 973 if (cfg2.fc_gw_family != AF_INET6 || 974 ipv6_addr_cmp(&cfg2.fc_gw6, 975 &nh->fib_nh_gw6)) 976 return 1; 977 break; 978 } 979 } 980 981 #ifdef CONFIG_IP_ROUTE_CLASSID 982 nla = nla_find(attrs, attrlen, RTA_FLOW); 983 if (nla) { 984 if (nla_len(nla) < sizeof(u32)) { 985 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 986 return -EINVAL; 987 } 988 if (nla_get_u32(nla) != nh->nh_tclassid) 989 return 1; 990 } 991 #endif 992 } 993 994 rtnh = rtnh_next(rtnh, &remaining); 995 } endfor_nexthops(fi); 996 #endif 997 return 0; 998 } 999 1000 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1001 { 1002 struct nlattr *nla; 1003 int remaining; 1004 1005 if (!cfg->fc_mx) 1006 return true; 1007 1008 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1009 int type = nla_type(nla); 1010 u32 fi_val, val; 1011 1012 if (!type) 1013 continue; 1014 if (type > RTAX_MAX) 1015 return false; 1016 1017 if (type == RTAX_CC_ALGO) { 1018 char tmp[TCP_CA_NAME_MAX]; 1019 bool ecn_ca = false; 1020 1021 nla_strscpy(tmp, nla, sizeof(tmp)); 1022 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1023 } else { 1024 if (nla_len(nla) != sizeof(u32)) 1025 return false; 1026 val = nla_get_u32(nla); 1027 } 1028 1029 fi_val = fi->fib_metrics->metrics[type - 1]; 1030 if (type == RTAX_FEATURES) 1031 fi_val &= ~DST_FEATURE_ECN_CA; 1032 1033 if (fi_val != val) 1034 return false; 1035 } 1036 1037 return true; 1038 } 1039 1040 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1041 u32 table, struct netlink_ext_ack *extack) 1042 { 1043 struct fib6_config cfg = { 1044 .fc_table = table, 1045 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1046 .fc_ifindex = nh->fib_nh_oif, 1047 .fc_gateway = nh->fib_nh_gw6, 1048 }; 1049 struct fib6_nh fib6_nh = {}; 1050 int err; 1051 1052 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1053 if (!err) { 1054 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1055 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL); 1056 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1057 nh->fib_nh_scope = RT_SCOPE_LINK; 1058 1059 ipv6_stub->fib6_nh_release(&fib6_nh); 1060 } 1061 1062 return err; 1063 } 1064 1065 /* 1066 * Picture 1067 * ------- 1068 * 1069 * Semantics of nexthop is very messy by historical reasons. 1070 * We have to take into account, that: 1071 * a) gateway can be actually local interface address, 1072 * so that gatewayed route is direct. 1073 * b) gateway must be on-link address, possibly 1074 * described not by an ifaddr, but also by a direct route. 1075 * c) If both gateway and interface are specified, they should not 1076 * contradict. 1077 * d) If we use tunnel routes, gateway could be not on-link. 1078 * 1079 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1080 * results in pretty ugly and hairy code with obscure logic. 1081 * 1082 * I chose to generalized it instead, so that the size 1083 * of code does not increase practically, but it becomes 1084 * much more general. 1085 * Every prefix is assigned a "scope" value: "host" is local address, 1086 * "link" is direct route, 1087 * [ ... "site" ... "interior" ... ] 1088 * and "universe" is true gateway route with global meaning. 1089 * 1090 * Every prefix refers to a set of "nexthop"s (gw, oif), 1091 * where gw must have narrower scope. This recursion stops 1092 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1093 * which means that gw is forced to be on link. 1094 * 1095 * Code is still hairy, but now it is apparently logically 1096 * consistent and very flexible. F.e. as by-product it allows 1097 * to co-exists in peace independent exterior and interior 1098 * routing processes. 1099 * 1100 * Normally it looks as following. 1101 * 1102 * {universe prefix} -> (gw, oif) [scope link] 1103 * | 1104 * |-> {link prefix} -> (gw, oif) [scope local] 1105 * | 1106 * |-> {local prefix} (terminal node) 1107 */ 1108 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1109 u8 scope, struct netlink_ext_ack *extack) 1110 { 1111 struct net_device *dev; 1112 struct fib_result res; 1113 int err = 0; 1114 1115 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1116 unsigned int addr_type; 1117 1118 if (scope >= RT_SCOPE_LINK) { 1119 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1120 return -EINVAL; 1121 } 1122 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1123 if (!dev) { 1124 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1125 return -ENODEV; 1126 } 1127 if (!(dev->flags & IFF_UP)) { 1128 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1129 return -ENETDOWN; 1130 } 1131 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1132 if (addr_type != RTN_UNICAST) { 1133 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1134 return -EINVAL; 1135 } 1136 if (!netif_carrier_ok(dev)) 1137 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1138 nh->fib_nh_dev = dev; 1139 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1140 nh->fib_nh_scope = RT_SCOPE_LINK; 1141 return 0; 1142 } 1143 rcu_read_lock(); 1144 { 1145 struct fib_table *tbl = NULL; 1146 struct flowi4 fl4 = { 1147 .daddr = nh->fib_nh_gw4, 1148 .flowi4_scope = scope + 1, 1149 .flowi4_oif = nh->fib_nh_oif, 1150 .flowi4_iif = LOOPBACK_IFINDEX, 1151 }; 1152 1153 /* It is not necessary, but requires a bit of thinking */ 1154 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1155 fl4.flowi4_scope = RT_SCOPE_LINK; 1156 1157 if (table && table != RT_TABLE_MAIN) 1158 tbl = fib_get_table(net, table); 1159 1160 if (tbl) 1161 err = fib_table_lookup(tbl, &fl4, &res, 1162 FIB_LOOKUP_IGNORE_LINKSTATE | 1163 FIB_LOOKUP_NOREF); 1164 1165 /* on error or if no table given do full lookup. This 1166 * is needed for example when nexthops are in the local 1167 * table rather than the given table 1168 */ 1169 if (!tbl || err) { 1170 err = fib_lookup(net, &fl4, &res, 1171 FIB_LOOKUP_IGNORE_LINKSTATE); 1172 } 1173 1174 if (err) { 1175 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1176 goto out; 1177 } 1178 } 1179 1180 err = -EINVAL; 1181 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1182 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1183 goto out; 1184 } 1185 nh->fib_nh_scope = res.scope; 1186 nh->fib_nh_oif = FIB_RES_OIF(res); 1187 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1188 if (!dev) { 1189 NL_SET_ERR_MSG(extack, 1190 "No egress device for nexthop gateway"); 1191 goto out; 1192 } 1193 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1194 if (!netif_carrier_ok(dev)) 1195 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1196 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1197 out: 1198 rcu_read_unlock(); 1199 return err; 1200 } 1201 1202 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1203 struct netlink_ext_ack *extack) 1204 { 1205 struct in_device *in_dev; 1206 int err; 1207 1208 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1209 NL_SET_ERR_MSG(extack, 1210 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1211 return -EINVAL; 1212 } 1213 1214 rcu_read_lock(); 1215 1216 err = -ENODEV; 1217 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1218 if (!in_dev) 1219 goto out; 1220 err = -ENETDOWN; 1221 if (!(in_dev->dev->flags & IFF_UP)) { 1222 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1223 goto out; 1224 } 1225 1226 nh->fib_nh_dev = in_dev->dev; 1227 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1228 nh->fib_nh_scope = RT_SCOPE_HOST; 1229 if (!netif_carrier_ok(nh->fib_nh_dev)) 1230 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1231 err = 0; 1232 out: 1233 rcu_read_unlock(); 1234 return err; 1235 } 1236 1237 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1238 struct netlink_ext_ack *extack) 1239 { 1240 int err; 1241 1242 if (nh->fib_nh_gw_family == AF_INET) 1243 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1244 else if (nh->fib_nh_gw_family == AF_INET6) 1245 err = fib_check_nh_v6_gw(net, nh, table, extack); 1246 else 1247 err = fib_check_nh_nongw(net, nh, extack); 1248 1249 return err; 1250 } 1251 1252 static struct hlist_head * 1253 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1254 { 1255 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1256 fib_info_hash_bits); 1257 1258 return &fib_info_laddrhash[slot]; 1259 } 1260 1261 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1262 struct hlist_head *new_laddrhash, 1263 unsigned int new_size) 1264 { 1265 struct hlist_head *old_info_hash, *old_laddrhash; 1266 unsigned int old_size = fib_info_hash_size; 1267 unsigned int i; 1268 1269 spin_lock_bh(&fib_info_lock); 1270 old_info_hash = fib_info_hash; 1271 old_laddrhash = fib_info_laddrhash; 1272 fib_info_hash_size = new_size; 1273 fib_info_hash_bits = ilog2(new_size); 1274 1275 for (i = 0; i < old_size; i++) { 1276 struct hlist_head *head = &fib_info_hash[i]; 1277 struct hlist_node *n; 1278 struct fib_info *fi; 1279 1280 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1281 struct hlist_head *dest; 1282 unsigned int new_hash; 1283 1284 new_hash = fib_info_hashfn(fi); 1285 dest = &new_info_hash[new_hash]; 1286 hlist_add_head(&fi->fib_hash, dest); 1287 } 1288 } 1289 fib_info_hash = new_info_hash; 1290 1291 fib_info_laddrhash = new_laddrhash; 1292 for (i = 0; i < old_size; i++) { 1293 struct hlist_head *lhead = &old_laddrhash[i]; 1294 struct hlist_node *n; 1295 struct fib_info *fi; 1296 1297 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1298 struct hlist_head *ldest; 1299 1300 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1301 fi->fib_prefsrc); 1302 hlist_add_head(&fi->fib_lhash, ldest); 1303 } 1304 } 1305 1306 spin_unlock_bh(&fib_info_lock); 1307 1308 kvfree(old_info_hash); 1309 kvfree(old_laddrhash); 1310 } 1311 1312 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1313 unsigned char scope) 1314 { 1315 struct fib_nh *nh; 1316 1317 if (nhc->nhc_family != AF_INET) 1318 return inet_select_addr(nhc->nhc_dev, 0, scope); 1319 1320 nh = container_of(nhc, struct fib_nh, nh_common); 1321 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1322 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1323 1324 return nh->nh_saddr; 1325 } 1326 1327 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1328 { 1329 struct fib_nh_common *nhc = res->nhc; 1330 1331 if (res->fi->fib_prefsrc) 1332 return res->fi->fib_prefsrc; 1333 1334 if (nhc->nhc_family == AF_INET) { 1335 struct fib_nh *nh; 1336 1337 nh = container_of(nhc, struct fib_nh, nh_common); 1338 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1339 return nh->nh_saddr; 1340 } 1341 1342 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1343 } 1344 1345 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1346 { 1347 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1348 fib_prefsrc != cfg->fc_dst) { 1349 u32 tb_id = cfg->fc_table; 1350 int rc; 1351 1352 if (tb_id == RT_TABLE_MAIN) 1353 tb_id = RT_TABLE_LOCAL; 1354 1355 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1356 fib_prefsrc, tb_id); 1357 1358 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1359 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1360 fib_prefsrc, RT_TABLE_LOCAL); 1361 } 1362 1363 if (rc != RTN_LOCAL) 1364 return false; 1365 } 1366 return true; 1367 } 1368 1369 struct fib_info *fib_create_info(struct fib_config *cfg, 1370 struct netlink_ext_ack *extack) 1371 { 1372 int err; 1373 struct fib_info *fi = NULL; 1374 struct nexthop *nh = NULL; 1375 struct fib_info *ofi; 1376 int nhs = 1; 1377 struct net *net = cfg->fc_nlinfo.nl_net; 1378 1379 if (cfg->fc_type > RTN_MAX) 1380 goto err_inval; 1381 1382 /* Fast check to catch the most weird cases */ 1383 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1384 NL_SET_ERR_MSG(extack, "Invalid scope"); 1385 goto err_inval; 1386 } 1387 1388 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1389 NL_SET_ERR_MSG(extack, 1390 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1391 goto err_inval; 1392 } 1393 1394 if (cfg->fc_nh_id) { 1395 if (!cfg->fc_mx) { 1396 fi = fib_find_info_nh(net, cfg); 1397 if (fi) { 1398 refcount_inc(&fi->fib_treeref); 1399 return fi; 1400 } 1401 } 1402 1403 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1404 if (!nh) { 1405 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1406 goto err_inval; 1407 } 1408 nhs = 0; 1409 } 1410 1411 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1412 if (cfg->fc_mp) { 1413 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1414 if (nhs == 0) 1415 goto err_inval; 1416 } 1417 #endif 1418 1419 err = -ENOBUFS; 1420 1421 /* Paired with WRITE_ONCE() in fib_release_info() */ 1422 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1423 unsigned int new_size = fib_info_hash_size << 1; 1424 struct hlist_head *new_info_hash; 1425 struct hlist_head *new_laddrhash; 1426 size_t bytes; 1427 1428 if (!new_size) 1429 new_size = 16; 1430 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1431 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1432 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1433 if (!new_info_hash || !new_laddrhash) { 1434 kvfree(new_info_hash); 1435 kvfree(new_laddrhash); 1436 } else { 1437 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1438 } 1439 if (!fib_info_hash_size) 1440 goto failure; 1441 } 1442 1443 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1444 if (!fi) 1445 goto failure; 1446 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1447 cfg->fc_mx_len, extack); 1448 if (IS_ERR(fi->fib_metrics)) { 1449 err = PTR_ERR(fi->fib_metrics); 1450 kfree(fi); 1451 return ERR_PTR(err); 1452 } 1453 1454 fi->fib_net = net; 1455 fi->fib_protocol = cfg->fc_protocol; 1456 fi->fib_scope = cfg->fc_scope; 1457 fi->fib_flags = cfg->fc_flags; 1458 fi->fib_priority = cfg->fc_priority; 1459 fi->fib_prefsrc = cfg->fc_prefsrc; 1460 fi->fib_type = cfg->fc_type; 1461 fi->fib_tb_id = cfg->fc_table; 1462 1463 fi->fib_nhs = nhs; 1464 if (nh) { 1465 if (!nexthop_get(nh)) { 1466 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1467 err = -EINVAL; 1468 } else { 1469 err = 0; 1470 fi->nh = nh; 1471 } 1472 } else { 1473 change_nexthops(fi) { 1474 nexthop_nh->nh_parent = fi; 1475 } endfor_nexthops(fi) 1476 1477 if (cfg->fc_mp) 1478 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1479 extack); 1480 else 1481 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1482 } 1483 1484 if (err != 0) 1485 goto failure; 1486 1487 if (fib_props[cfg->fc_type].error) { 1488 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1489 NL_SET_ERR_MSG(extack, 1490 "Gateway, device and multipath can not be specified for this route type"); 1491 goto err_inval; 1492 } 1493 goto link_it; 1494 } else { 1495 switch (cfg->fc_type) { 1496 case RTN_UNICAST: 1497 case RTN_LOCAL: 1498 case RTN_BROADCAST: 1499 case RTN_ANYCAST: 1500 case RTN_MULTICAST: 1501 break; 1502 default: 1503 NL_SET_ERR_MSG(extack, "Invalid route type"); 1504 goto err_inval; 1505 } 1506 } 1507 1508 if (cfg->fc_scope > RT_SCOPE_HOST) { 1509 NL_SET_ERR_MSG(extack, "Invalid scope"); 1510 goto err_inval; 1511 } 1512 1513 if (fi->nh) { 1514 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1515 if (err) 1516 goto failure; 1517 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1518 struct fib_nh *nh = fi->fib_nh; 1519 1520 /* Local address is added. */ 1521 if (nhs != 1) { 1522 NL_SET_ERR_MSG(extack, 1523 "Route with host scope can not have multiple nexthops"); 1524 goto err_inval; 1525 } 1526 if (nh->fib_nh_gw_family) { 1527 NL_SET_ERR_MSG(extack, 1528 "Route with host scope can not have a gateway"); 1529 goto err_inval; 1530 } 1531 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1532 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1533 err = -ENODEV; 1534 if (!nh->fib_nh_dev) 1535 goto failure; 1536 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1537 GFP_KERNEL); 1538 } else { 1539 int linkdown = 0; 1540 1541 change_nexthops(fi) { 1542 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1543 cfg->fc_table, cfg->fc_scope, 1544 extack); 1545 if (err != 0) 1546 goto failure; 1547 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1548 linkdown++; 1549 } endfor_nexthops(fi) 1550 if (linkdown == fi->fib_nhs) 1551 fi->fib_flags |= RTNH_F_LINKDOWN; 1552 } 1553 1554 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1555 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1556 goto err_inval; 1557 } 1558 1559 if (!fi->nh) { 1560 change_nexthops(fi) { 1561 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1562 fi->fib_scope); 1563 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1564 fi->fib_nh_is_v6 = true; 1565 } endfor_nexthops(fi) 1566 1567 fib_rebalance(fi); 1568 } 1569 1570 link_it: 1571 ofi = fib_find_info(fi); 1572 if (ofi) { 1573 fi->fib_dead = 1; 1574 free_fib_info(fi); 1575 refcount_inc(&ofi->fib_treeref); 1576 return ofi; 1577 } 1578 1579 refcount_set(&fi->fib_treeref, 1); 1580 refcount_set(&fi->fib_clntref, 1); 1581 spin_lock_bh(&fib_info_lock); 1582 fib_info_cnt++; 1583 hlist_add_head(&fi->fib_hash, 1584 &fib_info_hash[fib_info_hashfn(fi)]); 1585 if (fi->fib_prefsrc) { 1586 struct hlist_head *head; 1587 1588 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1589 hlist_add_head(&fi->fib_lhash, head); 1590 } 1591 if (fi->nh) { 1592 list_add(&fi->nh_list, &nh->fi_list); 1593 } else { 1594 change_nexthops(fi) { 1595 struct hlist_head *head; 1596 1597 if (!nexthop_nh->fib_nh_dev) 1598 continue; 1599 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1600 hlist_add_head(&nexthop_nh->nh_hash, head); 1601 } endfor_nexthops(fi) 1602 } 1603 spin_unlock_bh(&fib_info_lock); 1604 return fi; 1605 1606 err_inval: 1607 err = -EINVAL; 1608 1609 failure: 1610 if (fi) { 1611 fi->fib_dead = 1; 1612 free_fib_info(fi); 1613 } 1614 1615 return ERR_PTR(err); 1616 } 1617 1618 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1619 u8 rt_family, unsigned char *flags, bool skip_oif) 1620 { 1621 if (nhc->nhc_flags & RTNH_F_DEAD) 1622 *flags |= RTNH_F_DEAD; 1623 1624 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1625 *flags |= RTNH_F_LINKDOWN; 1626 1627 rcu_read_lock(); 1628 switch (nhc->nhc_family) { 1629 case AF_INET: 1630 if (ip_ignore_linkdown(nhc->nhc_dev)) 1631 *flags |= RTNH_F_DEAD; 1632 break; 1633 case AF_INET6: 1634 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1635 *flags |= RTNH_F_DEAD; 1636 break; 1637 } 1638 rcu_read_unlock(); 1639 } 1640 1641 switch (nhc->nhc_gw_family) { 1642 case AF_INET: 1643 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1644 goto nla_put_failure; 1645 break; 1646 case AF_INET6: 1647 /* if gateway family does not match nexthop family 1648 * gateway is encoded as RTA_VIA 1649 */ 1650 if (rt_family != nhc->nhc_gw_family) { 1651 int alen = sizeof(struct in6_addr); 1652 struct nlattr *nla; 1653 struct rtvia *via; 1654 1655 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1656 if (!nla) 1657 goto nla_put_failure; 1658 1659 via = nla_data(nla); 1660 via->rtvia_family = AF_INET6; 1661 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1662 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1663 &nhc->nhc_gw.ipv6) < 0) { 1664 goto nla_put_failure; 1665 } 1666 break; 1667 } 1668 1669 *flags |= (nhc->nhc_flags & 1670 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1671 1672 if (!skip_oif && nhc->nhc_dev && 1673 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1674 goto nla_put_failure; 1675 1676 if (nhc->nhc_lwtstate && 1677 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1678 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1679 goto nla_put_failure; 1680 1681 return 0; 1682 1683 nla_put_failure: 1684 return -EMSGSIZE; 1685 } 1686 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1687 1688 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1689 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1690 int nh_weight, u8 rt_family, u32 nh_tclassid) 1691 { 1692 const struct net_device *dev = nhc->nhc_dev; 1693 struct rtnexthop *rtnh; 1694 unsigned char flags = 0; 1695 1696 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1697 if (!rtnh) 1698 goto nla_put_failure; 1699 1700 rtnh->rtnh_hops = nh_weight - 1; 1701 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1702 1703 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1704 goto nla_put_failure; 1705 1706 rtnh->rtnh_flags = flags; 1707 1708 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1709 goto nla_put_failure; 1710 1711 /* length of rtnetlink header + attributes */ 1712 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1713 1714 return 0; 1715 1716 nla_put_failure: 1717 return -EMSGSIZE; 1718 } 1719 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1720 #endif 1721 1722 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1723 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1724 { 1725 struct nlattr *mp; 1726 1727 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1728 if (!mp) 1729 goto nla_put_failure; 1730 1731 if (unlikely(fi->nh)) { 1732 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1733 goto nla_put_failure; 1734 goto mp_end; 1735 } 1736 1737 for_nexthops(fi) { 1738 u32 nh_tclassid = 0; 1739 #ifdef CONFIG_IP_ROUTE_CLASSID 1740 nh_tclassid = nh->nh_tclassid; 1741 #endif 1742 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1743 AF_INET, nh_tclassid) < 0) 1744 goto nla_put_failure; 1745 } endfor_nexthops(fi); 1746 1747 mp_end: 1748 nla_nest_end(skb, mp); 1749 1750 return 0; 1751 1752 nla_put_failure: 1753 return -EMSGSIZE; 1754 } 1755 #else 1756 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1757 { 1758 return 0; 1759 } 1760 #endif 1761 1762 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1763 const struct fib_rt_info *fri, unsigned int flags) 1764 { 1765 unsigned int nhs = fib_info_num_path(fri->fi); 1766 struct fib_info *fi = fri->fi; 1767 u32 tb_id = fri->tb_id; 1768 struct nlmsghdr *nlh; 1769 struct rtmsg *rtm; 1770 1771 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1772 if (!nlh) 1773 return -EMSGSIZE; 1774 1775 rtm = nlmsg_data(nlh); 1776 rtm->rtm_family = AF_INET; 1777 rtm->rtm_dst_len = fri->dst_len; 1778 rtm->rtm_src_len = 0; 1779 rtm->rtm_tos = fri->tos; 1780 if (tb_id < 256) 1781 rtm->rtm_table = tb_id; 1782 else 1783 rtm->rtm_table = RT_TABLE_COMPAT; 1784 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1785 goto nla_put_failure; 1786 rtm->rtm_type = fri->type; 1787 rtm->rtm_flags = fi->fib_flags; 1788 rtm->rtm_scope = fi->fib_scope; 1789 rtm->rtm_protocol = fi->fib_protocol; 1790 1791 if (rtm->rtm_dst_len && 1792 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1793 goto nla_put_failure; 1794 if (fi->fib_priority && 1795 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1796 goto nla_put_failure; 1797 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1798 goto nla_put_failure; 1799 1800 if (fi->fib_prefsrc && 1801 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1802 goto nla_put_failure; 1803 1804 if (fi->nh) { 1805 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1806 goto nla_put_failure; 1807 if (nexthop_is_blackhole(fi->nh)) 1808 rtm->rtm_type = RTN_BLACKHOLE; 1809 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode) 1810 goto offload; 1811 } 1812 1813 if (nhs == 1) { 1814 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1815 unsigned char flags = 0; 1816 1817 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1818 goto nla_put_failure; 1819 1820 rtm->rtm_flags = flags; 1821 #ifdef CONFIG_IP_ROUTE_CLASSID 1822 if (nhc->nhc_family == AF_INET) { 1823 struct fib_nh *nh; 1824 1825 nh = container_of(nhc, struct fib_nh, nh_common); 1826 if (nh->nh_tclassid && 1827 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1828 goto nla_put_failure; 1829 } 1830 #endif 1831 } else { 1832 if (fib_add_multipath(skb, fi) < 0) 1833 goto nla_put_failure; 1834 } 1835 1836 offload: 1837 if (fri->offload) 1838 rtm->rtm_flags |= RTM_F_OFFLOAD; 1839 if (fri->trap) 1840 rtm->rtm_flags |= RTM_F_TRAP; 1841 if (fri->offload_failed) 1842 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1843 1844 nlmsg_end(skb, nlh); 1845 return 0; 1846 1847 nla_put_failure: 1848 nlmsg_cancel(skb, nlh); 1849 return -EMSGSIZE; 1850 } 1851 1852 /* 1853 * Update FIB if: 1854 * - local address disappeared -> we must delete all the entries 1855 * referring to it. 1856 * - device went down -> we must shutdown all nexthops going via it. 1857 */ 1858 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1859 { 1860 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1861 struct net *net = dev_net(dev); 1862 struct hlist_head *head; 1863 struct fib_info *fi; 1864 int ret = 0; 1865 1866 if (!fib_info_laddrhash || local == 0) 1867 return 0; 1868 1869 head = fib_info_laddrhash_bucket(net, local); 1870 hlist_for_each_entry(fi, head, fib_lhash) { 1871 if (!net_eq(fi->fib_net, net) || 1872 fi->fib_tb_id != tb_id) 1873 continue; 1874 if (fi->fib_prefsrc == local) { 1875 fi->fib_flags |= RTNH_F_DEAD; 1876 ret++; 1877 } 1878 } 1879 return ret; 1880 } 1881 1882 static int call_fib_nh_notifiers(struct fib_nh *nh, 1883 enum fib_event_type event_type) 1884 { 1885 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1886 struct fib_nh_notifier_info info = { 1887 .fib_nh = nh, 1888 }; 1889 1890 switch (event_type) { 1891 case FIB_EVENT_NH_ADD: 1892 if (nh->fib_nh_flags & RTNH_F_DEAD) 1893 break; 1894 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1895 break; 1896 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1897 &info.info); 1898 case FIB_EVENT_NH_DEL: 1899 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1900 (nh->fib_nh_flags & RTNH_F_DEAD)) 1901 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1902 event_type, &info.info); 1903 break; 1904 default: 1905 break; 1906 } 1907 1908 return NOTIFY_DONE; 1909 } 1910 1911 /* Update the PMTU of exceptions when: 1912 * - the new MTU of the first hop becomes smaller than the PMTU 1913 * - the old MTU was the same as the PMTU, and it limited discovery of 1914 * larger MTUs on the path. With that limit raised, we can now 1915 * discover larger MTUs 1916 * A special case is locked exceptions, for which the PMTU is smaller 1917 * than the minimal accepted PMTU: 1918 * - if the new MTU is greater than the PMTU, don't make any change 1919 * - otherwise, unlock and set PMTU 1920 */ 1921 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1922 { 1923 struct fnhe_hash_bucket *bucket; 1924 int i; 1925 1926 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1927 if (!bucket) 1928 return; 1929 1930 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1931 struct fib_nh_exception *fnhe; 1932 1933 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1934 fnhe; 1935 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1936 if (fnhe->fnhe_mtu_locked) { 1937 if (new <= fnhe->fnhe_pmtu) { 1938 fnhe->fnhe_pmtu = new; 1939 fnhe->fnhe_mtu_locked = false; 1940 } 1941 } else if (new < fnhe->fnhe_pmtu || 1942 orig == fnhe->fnhe_pmtu) { 1943 fnhe->fnhe_pmtu = new; 1944 } 1945 } 1946 } 1947 } 1948 1949 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1950 { 1951 struct hlist_head *head = fib_info_devhash_bucket(dev); 1952 struct fib_nh *nh; 1953 1954 hlist_for_each_entry(nh, head, nh_hash) { 1955 if (nh->fib_nh_dev == dev) 1956 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1957 } 1958 } 1959 1960 /* Event force Flags Description 1961 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1962 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1963 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1964 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1965 * 1966 * only used when fib_nh is built into fib_info 1967 */ 1968 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1969 { 1970 struct hlist_head *head = fib_info_devhash_bucket(dev); 1971 struct fib_info *prev_fi = NULL; 1972 int scope = RT_SCOPE_NOWHERE; 1973 struct fib_nh *nh; 1974 int ret = 0; 1975 1976 if (force) 1977 scope = -1; 1978 1979 hlist_for_each_entry(nh, head, nh_hash) { 1980 struct fib_info *fi = nh->nh_parent; 1981 int dead; 1982 1983 BUG_ON(!fi->fib_nhs); 1984 if (nh->fib_nh_dev != dev || fi == prev_fi) 1985 continue; 1986 prev_fi = fi; 1987 dead = 0; 1988 change_nexthops(fi) { 1989 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1990 dead++; 1991 else if (nexthop_nh->fib_nh_dev == dev && 1992 nexthop_nh->fib_nh_scope != scope) { 1993 switch (event) { 1994 case NETDEV_DOWN: 1995 case NETDEV_UNREGISTER: 1996 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 1997 fallthrough; 1998 case NETDEV_CHANGE: 1999 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2000 break; 2001 } 2002 call_fib_nh_notifiers(nexthop_nh, 2003 FIB_EVENT_NH_DEL); 2004 dead++; 2005 } 2006 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2007 if (event == NETDEV_UNREGISTER && 2008 nexthop_nh->fib_nh_dev == dev) { 2009 dead = fi->fib_nhs; 2010 break; 2011 } 2012 #endif 2013 } endfor_nexthops(fi) 2014 if (dead == fi->fib_nhs) { 2015 switch (event) { 2016 case NETDEV_DOWN: 2017 case NETDEV_UNREGISTER: 2018 fi->fib_flags |= RTNH_F_DEAD; 2019 fallthrough; 2020 case NETDEV_CHANGE: 2021 fi->fib_flags |= RTNH_F_LINKDOWN; 2022 break; 2023 } 2024 ret++; 2025 } 2026 2027 fib_rebalance(fi); 2028 } 2029 2030 return ret; 2031 } 2032 2033 /* Must be invoked inside of an RCU protected region. */ 2034 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2035 { 2036 struct fib_info *fi = NULL, *last_resort = NULL; 2037 struct hlist_head *fa_head = res->fa_head; 2038 struct fib_table *tb = res->table; 2039 u8 slen = 32 - res->prefixlen; 2040 int order = -1, last_idx = -1; 2041 struct fib_alias *fa, *fa1 = NULL; 2042 u32 last_prio = res->fi->fib_priority; 2043 dscp_t last_dscp = 0; 2044 2045 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2046 struct fib_info *next_fi = fa->fa_info; 2047 struct fib_nh_common *nhc; 2048 2049 if (fa->fa_slen != slen) 2050 continue; 2051 if (fa->fa_dscp && 2052 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos)) 2053 continue; 2054 if (fa->tb_id != tb->tb_id) 2055 continue; 2056 if (next_fi->fib_priority > last_prio && 2057 fa->fa_dscp == last_dscp) { 2058 if (last_dscp) 2059 continue; 2060 break; 2061 } 2062 if (next_fi->fib_flags & RTNH_F_DEAD) 2063 continue; 2064 last_dscp = fa->fa_dscp; 2065 last_prio = next_fi->fib_priority; 2066 2067 if (next_fi->fib_scope != res->scope || 2068 fa->fa_type != RTN_UNICAST) 2069 continue; 2070 2071 nhc = fib_info_nhc(next_fi, 0); 2072 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2073 continue; 2074 2075 fib_alias_accessed(fa); 2076 2077 if (!fi) { 2078 if (next_fi != res->fi) 2079 break; 2080 fa1 = fa; 2081 } else if (!fib_detect_death(fi, order, &last_resort, 2082 &last_idx, fa1->fa_default)) { 2083 fib_result_assign(res, fi); 2084 fa1->fa_default = order; 2085 goto out; 2086 } 2087 fi = next_fi; 2088 order++; 2089 } 2090 2091 if (order <= 0 || !fi) { 2092 if (fa1) 2093 fa1->fa_default = -1; 2094 goto out; 2095 } 2096 2097 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2098 fa1->fa_default)) { 2099 fib_result_assign(res, fi); 2100 fa1->fa_default = order; 2101 goto out; 2102 } 2103 2104 if (last_idx >= 0) 2105 fib_result_assign(res, last_resort); 2106 fa1->fa_default = last_idx; 2107 out: 2108 return; 2109 } 2110 2111 /* 2112 * Dead device goes up. We wake up dead nexthops. 2113 * It takes sense only on multipath routes. 2114 * 2115 * only used when fib_nh is built into fib_info 2116 */ 2117 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2118 { 2119 struct fib_info *prev_fi; 2120 struct hlist_head *head; 2121 struct fib_nh *nh; 2122 int ret; 2123 2124 if (!(dev->flags & IFF_UP)) 2125 return 0; 2126 2127 if (nh_flags & RTNH_F_DEAD) { 2128 unsigned int flags = dev_get_flags(dev); 2129 2130 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2131 nh_flags |= RTNH_F_LINKDOWN; 2132 } 2133 2134 prev_fi = NULL; 2135 head = fib_info_devhash_bucket(dev); 2136 ret = 0; 2137 2138 hlist_for_each_entry(nh, head, nh_hash) { 2139 struct fib_info *fi = nh->nh_parent; 2140 int alive; 2141 2142 BUG_ON(!fi->fib_nhs); 2143 if (nh->fib_nh_dev != dev || fi == prev_fi) 2144 continue; 2145 2146 prev_fi = fi; 2147 alive = 0; 2148 change_nexthops(fi) { 2149 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2150 alive++; 2151 continue; 2152 } 2153 if (!nexthop_nh->fib_nh_dev || 2154 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2155 continue; 2156 if (nexthop_nh->fib_nh_dev != dev || 2157 !__in_dev_get_rtnl(dev)) 2158 continue; 2159 alive++; 2160 nexthop_nh->fib_nh_flags &= ~nh_flags; 2161 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2162 } endfor_nexthops(fi) 2163 2164 if (alive > 0) { 2165 fi->fib_flags &= ~nh_flags; 2166 ret++; 2167 } 2168 2169 fib_rebalance(fi); 2170 } 2171 2172 return ret; 2173 } 2174 2175 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2176 static bool fib_good_nh(const struct fib_nh *nh) 2177 { 2178 int state = NUD_REACHABLE; 2179 2180 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2181 struct neighbour *n; 2182 2183 rcu_read_lock_bh(); 2184 2185 if (likely(nh->fib_nh_gw_family == AF_INET)) 2186 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2187 (__force u32)nh->fib_nh_gw4); 2188 else if (nh->fib_nh_gw_family == AF_INET6) 2189 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2190 &nh->fib_nh_gw6); 2191 else 2192 n = NULL; 2193 if (n) 2194 state = n->nud_state; 2195 2196 rcu_read_unlock_bh(); 2197 } 2198 2199 return !!(state & NUD_VALID); 2200 } 2201 2202 void fib_select_multipath(struct fib_result *res, int hash) 2203 { 2204 struct fib_info *fi = res->fi; 2205 struct net *net = fi->fib_net; 2206 bool first = false; 2207 2208 if (unlikely(res->fi->nh)) { 2209 nexthop_path_fib_result(res, hash); 2210 return; 2211 } 2212 2213 change_nexthops(fi) { 2214 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 2215 if (!fib_good_nh(nexthop_nh)) 2216 continue; 2217 if (!first) { 2218 res->nh_sel = nhsel; 2219 res->nhc = &nexthop_nh->nh_common; 2220 first = true; 2221 } 2222 } 2223 2224 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2225 continue; 2226 2227 res->nh_sel = nhsel; 2228 res->nhc = &nexthop_nh->nh_common; 2229 return; 2230 } endfor_nexthops(fi); 2231 } 2232 #endif 2233 2234 void fib_select_path(struct net *net, struct fib_result *res, 2235 struct flowi4 *fl4, const struct sk_buff *skb) 2236 { 2237 if (fl4->flowi4_oif) 2238 goto check_saddr; 2239 2240 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2241 if (fib_info_num_path(res->fi) > 1) { 2242 int h = fib_multipath_hash(net, fl4, skb, NULL); 2243 2244 fib_select_multipath(res, h); 2245 } 2246 else 2247 #endif 2248 if (!res->prefixlen && 2249 res->table->tb_num_default > 1 && 2250 res->type == RTN_UNICAST) 2251 fib_select_default(fl4, res); 2252 2253 check_saddr: 2254 if (!fl4->saddr) 2255 fl4->saddr = fib_result_prefsrc(net, res); 2256 } 2257