1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * IPv4 Forwarding Information Base: semantics. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 */ 11 12 #include <linux/uaccess.h> 13 #include <linux/bitops.h> 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/jiffies.h> 17 #include <linux/mm.h> 18 #include <linux/string.h> 19 #include <linux/socket.h> 20 #include <linux/sockios.h> 21 #include <linux/errno.h> 22 #include <linux/in.h> 23 #include <linux/inet.h> 24 #include <linux/inetdevice.h> 25 #include <linux/netdevice.h> 26 #include <linux/if_arp.h> 27 #include <linux/proc_fs.h> 28 #include <linux/skbuff.h> 29 #include <linux/init.h> 30 #include <linux/slab.h> 31 #include <linux/netlink.h> 32 #include <linux/hash.h> 33 #include <linux/nospec.h> 34 35 #include <net/arp.h> 36 #include <net/inet_dscp.h> 37 #include <net/ip.h> 38 #include <net/protocol.h> 39 #include <net/route.h> 40 #include <net/tcp.h> 41 #include <net/sock.h> 42 #include <net/ip_fib.h> 43 #include <net/ip6_fib.h> 44 #include <net/nexthop.h> 45 #include <net/netlink.h> 46 #include <net/rtnh.h> 47 #include <net/lwtunnel.h> 48 #include <net/fib_notifier.h> 49 #include <net/addrconf.h> 50 51 #include "fib_lookup.h" 52 53 static DEFINE_SPINLOCK(fib_info_lock); 54 static struct hlist_head *fib_info_hash; 55 static struct hlist_head *fib_info_laddrhash; 56 static unsigned int fib_info_hash_size; 57 static unsigned int fib_info_hash_bits; 58 static unsigned int fib_info_cnt; 59 60 #define DEVINDEX_HASHBITS 8 61 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 62 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 63 64 /* for_nexthops and change_nexthops only used when nexthop object 65 * is not set in a fib_info. The logic within can reference fib_nh. 66 */ 67 #ifdef CONFIG_IP_ROUTE_MULTIPATH 68 69 #define for_nexthops(fi) { \ 70 int nhsel; const struct fib_nh *nh; \ 71 for (nhsel = 0, nh = (fi)->fib_nh; \ 72 nhsel < fib_info_num_path((fi)); \ 73 nh++, nhsel++) 74 75 #define change_nexthops(fi) { \ 76 int nhsel; struct fib_nh *nexthop_nh; \ 77 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 78 nhsel < fib_info_num_path((fi)); \ 79 nexthop_nh++, nhsel++) 80 81 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 82 83 /* Hope, that gcc will optimize it to get rid of dummy loop */ 84 85 #define for_nexthops(fi) { \ 86 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 87 for (nhsel = 0; nhsel < 1; nhsel++) 88 89 #define change_nexthops(fi) { \ 90 int nhsel; \ 91 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 92 for (nhsel = 0; nhsel < 1; nhsel++) 93 94 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 95 96 #define endfor_nexthops(fi) } 97 98 99 const struct fib_prop fib_props[RTN_MAX + 1] = { 100 [RTN_UNSPEC] = { 101 .error = 0, 102 .scope = RT_SCOPE_NOWHERE, 103 }, 104 [RTN_UNICAST] = { 105 .error = 0, 106 .scope = RT_SCOPE_UNIVERSE, 107 }, 108 [RTN_LOCAL] = { 109 .error = 0, 110 .scope = RT_SCOPE_HOST, 111 }, 112 [RTN_BROADCAST] = { 113 .error = 0, 114 .scope = RT_SCOPE_LINK, 115 }, 116 [RTN_ANYCAST] = { 117 .error = 0, 118 .scope = RT_SCOPE_LINK, 119 }, 120 [RTN_MULTICAST] = { 121 .error = 0, 122 .scope = RT_SCOPE_UNIVERSE, 123 }, 124 [RTN_BLACKHOLE] = { 125 .error = -EINVAL, 126 .scope = RT_SCOPE_UNIVERSE, 127 }, 128 [RTN_UNREACHABLE] = { 129 .error = -EHOSTUNREACH, 130 .scope = RT_SCOPE_UNIVERSE, 131 }, 132 [RTN_PROHIBIT] = { 133 .error = -EACCES, 134 .scope = RT_SCOPE_UNIVERSE, 135 }, 136 [RTN_THROW] = { 137 .error = -EAGAIN, 138 .scope = RT_SCOPE_UNIVERSE, 139 }, 140 [RTN_NAT] = { 141 .error = -EINVAL, 142 .scope = RT_SCOPE_NOWHERE, 143 }, 144 [RTN_XRESOLVE] = { 145 .error = -EINVAL, 146 .scope = RT_SCOPE_NOWHERE, 147 }, 148 }; 149 150 static void rt_fibinfo_free(struct rtable __rcu **rtp) 151 { 152 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 153 154 if (!rt) 155 return; 156 157 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 158 * because we waited an RCU grace period before calling 159 * free_fib_info_rcu() 160 */ 161 162 dst_dev_put(&rt->dst); 163 dst_release_immediate(&rt->dst); 164 } 165 166 static void free_nh_exceptions(struct fib_nh_common *nhc) 167 { 168 struct fnhe_hash_bucket *hash; 169 int i; 170 171 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); 172 if (!hash) 173 return; 174 for (i = 0; i < FNHE_HASH_SIZE; i++) { 175 struct fib_nh_exception *fnhe; 176 177 fnhe = rcu_dereference_protected(hash[i].chain, 1); 178 while (fnhe) { 179 struct fib_nh_exception *next; 180 181 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 182 183 rt_fibinfo_free(&fnhe->fnhe_rth_input); 184 rt_fibinfo_free(&fnhe->fnhe_rth_output); 185 186 kfree(fnhe); 187 188 fnhe = next; 189 } 190 } 191 kfree(hash); 192 } 193 194 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 195 { 196 int cpu; 197 198 if (!rtp) 199 return; 200 201 for_each_possible_cpu(cpu) { 202 struct rtable *rt; 203 204 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 205 if (rt) { 206 dst_dev_put(&rt->dst); 207 dst_release_immediate(&rt->dst); 208 } 209 } 210 free_percpu(rtp); 211 } 212 213 void fib_nh_common_release(struct fib_nh_common *nhc) 214 { 215 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker); 216 lwtstate_put(nhc->nhc_lwtstate); 217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 218 rt_fibinfo_free(&nhc->nhc_rth_input); 219 free_nh_exceptions(nhc); 220 } 221 EXPORT_SYMBOL_GPL(fib_nh_common_release); 222 223 void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 224 { 225 #ifdef CONFIG_IP_ROUTE_CLASSID 226 if (fib_nh->nh_tclassid) 227 atomic_dec(&net->ipv4.fib_num_tclassid_users); 228 #endif 229 fib_nh_common_release(&fib_nh->nh_common); 230 } 231 232 /* Release a nexthop info record */ 233 static void free_fib_info_rcu(struct rcu_head *head) 234 { 235 struct fib_info *fi = container_of(head, struct fib_info, rcu); 236 237 if (fi->nh) { 238 nexthop_put(fi->nh); 239 } else { 240 change_nexthops(fi) { 241 fib_nh_release(fi->fib_net, nexthop_nh); 242 } endfor_nexthops(fi); 243 } 244 245 ip_fib_metrics_put(fi->fib_metrics); 246 247 kfree(fi); 248 } 249 250 void free_fib_info(struct fib_info *fi) 251 { 252 if (fi->fib_dead == 0) { 253 pr_warn("Freeing alive fib_info %p\n", fi); 254 return; 255 } 256 257 call_rcu(&fi->rcu, free_fib_info_rcu); 258 } 259 EXPORT_SYMBOL_GPL(free_fib_info); 260 261 void fib_release_info(struct fib_info *fi) 262 { 263 spin_lock_bh(&fib_info_lock); 264 if (fi && refcount_dec_and_test(&fi->fib_treeref)) { 265 hlist_del(&fi->fib_hash); 266 267 /* Paired with READ_ONCE() in fib_create_info(). */ 268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1); 269 270 if (fi->fib_prefsrc) 271 hlist_del(&fi->fib_lhash); 272 if (fi->nh) { 273 list_del(&fi->nh_list); 274 } else { 275 change_nexthops(fi) { 276 if (!nexthop_nh->fib_nh_dev) 277 continue; 278 hlist_del(&nexthop_nh->nh_hash); 279 } endfor_nexthops(fi) 280 } 281 fi->fib_dead = 1; 282 fib_info_put(fi); 283 } 284 spin_unlock_bh(&fib_info_lock); 285 } 286 287 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 288 { 289 const struct fib_nh *onh; 290 291 if (fi->nh || ofi->nh) 292 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 293 294 if (ofi->fib_nhs == 0) 295 return 0; 296 297 for_nexthops(fi) { 298 onh = fib_info_nh(ofi, nhsel); 299 300 if (nh->fib_nh_oif != onh->fib_nh_oif || 301 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 302 nh->fib_nh_scope != onh->fib_nh_scope || 303 #ifdef CONFIG_IP_ROUTE_MULTIPATH 304 nh->fib_nh_weight != onh->fib_nh_weight || 305 #endif 306 #ifdef CONFIG_IP_ROUTE_CLASSID 307 nh->nh_tclassid != onh->nh_tclassid || 308 #endif 309 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 310 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 311 return -1; 312 313 if (nh->fib_nh_gw_family == AF_INET && 314 nh->fib_nh_gw4 != onh->fib_nh_gw4) 315 return -1; 316 317 if (nh->fib_nh_gw_family == AF_INET6 && 318 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 319 return -1; 320 } endfor_nexthops(fi); 321 return 0; 322 } 323 324 static inline unsigned int fib_devindex_hashfn(unsigned int val) 325 { 326 return hash_32(val, DEVINDEX_HASHBITS); 327 } 328 329 static struct hlist_head * 330 fib_info_devhash_bucket(const struct net_device *dev) 331 { 332 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex; 333 334 return &fib_info_devhash[fib_devindex_hashfn(val)]; 335 } 336 337 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 338 u32 prefsrc, u32 priority) 339 { 340 unsigned int val = init_val; 341 342 val ^= (protocol << 8) | scope; 343 val ^= prefsrc; 344 val ^= priority; 345 346 return val; 347 } 348 349 static unsigned int fib_info_hashfn_result(unsigned int val) 350 { 351 unsigned int mask = (fib_info_hash_size - 1); 352 353 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 354 } 355 356 static inline unsigned int fib_info_hashfn(struct fib_info *fi) 357 { 358 unsigned int val; 359 360 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 361 fi->fib_scope, (__force u32)fi->fib_prefsrc, 362 fi->fib_priority); 363 364 if (fi->nh) { 365 val ^= fib_devindex_hashfn(fi->nh->id); 366 } else { 367 for_nexthops(fi) { 368 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 369 } endfor_nexthops(fi) 370 } 371 372 return fib_info_hashfn_result(val); 373 } 374 375 /* no metrics, only nexthop id */ 376 static struct fib_info *fib_find_info_nh(struct net *net, 377 const struct fib_config *cfg) 378 { 379 struct hlist_head *head; 380 struct fib_info *fi; 381 unsigned int hash; 382 383 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 384 cfg->fc_protocol, cfg->fc_scope, 385 (__force u32)cfg->fc_prefsrc, 386 cfg->fc_priority); 387 hash = fib_info_hashfn_result(hash); 388 head = &fib_info_hash[hash]; 389 390 hlist_for_each_entry(fi, head, fib_hash) { 391 if (!net_eq(fi->fib_net, net)) 392 continue; 393 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 394 continue; 395 if (cfg->fc_protocol == fi->fib_protocol && 396 cfg->fc_scope == fi->fib_scope && 397 cfg->fc_prefsrc == fi->fib_prefsrc && 398 cfg->fc_priority == fi->fib_priority && 399 cfg->fc_type == fi->fib_type && 400 cfg->fc_table == fi->fib_tb_id && 401 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 402 return fi; 403 } 404 405 return NULL; 406 } 407 408 static struct fib_info *fib_find_info(struct fib_info *nfi) 409 { 410 struct hlist_head *head; 411 struct fib_info *fi; 412 unsigned int hash; 413 414 hash = fib_info_hashfn(nfi); 415 head = &fib_info_hash[hash]; 416 417 hlist_for_each_entry(fi, head, fib_hash) { 418 if (!net_eq(fi->fib_net, nfi->fib_net)) 419 continue; 420 if (fi->fib_nhs != nfi->fib_nhs) 421 continue; 422 if (nfi->fib_protocol == fi->fib_protocol && 423 nfi->fib_scope == fi->fib_scope && 424 nfi->fib_prefsrc == fi->fib_prefsrc && 425 nfi->fib_priority == fi->fib_priority && 426 nfi->fib_type == fi->fib_type && 427 nfi->fib_tb_id == fi->fib_tb_id && 428 memcmp(nfi->fib_metrics, fi->fib_metrics, 429 sizeof(u32) * RTAX_MAX) == 0 && 430 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 431 nh_comp(fi, nfi) == 0) 432 return fi; 433 } 434 435 return NULL; 436 } 437 438 /* Check, that the gateway is already configured. 439 * Used only by redirect accept routine. 440 */ 441 int ip_fib_check_default(__be32 gw, struct net_device *dev) 442 { 443 struct hlist_head *head; 444 struct fib_nh *nh; 445 446 spin_lock(&fib_info_lock); 447 448 head = fib_info_devhash_bucket(dev); 449 450 hlist_for_each_entry(nh, head, nh_hash) { 451 if (nh->fib_nh_dev == dev && 452 nh->fib_nh_gw4 == gw && 453 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 454 spin_unlock(&fib_info_lock); 455 return 0; 456 } 457 } 458 459 spin_unlock(&fib_info_lock); 460 461 return -1; 462 } 463 464 size_t fib_nlmsg_size(struct fib_info *fi) 465 { 466 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 467 + nla_total_size(4) /* RTA_TABLE */ 468 + nla_total_size(4) /* RTA_DST */ 469 + nla_total_size(4) /* RTA_PRIORITY */ 470 + nla_total_size(4) /* RTA_PREFSRC */ 471 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 472 unsigned int nhs = fib_info_num_path(fi); 473 474 /* space for nested metrics */ 475 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 476 477 if (fi->nh) 478 payload += nla_total_size(4); /* RTA_NH_ID */ 479 480 if (nhs) { 481 size_t nh_encapsize = 0; 482 /* Also handles the special case nhs == 1 */ 483 484 /* each nexthop is packed in an attribute */ 485 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 486 unsigned int i; 487 488 /* may contain flow and gateway attribute */ 489 nhsize += 2 * nla_total_size(4); 490 491 /* grab encap info */ 492 for (i = 0; i < fib_info_num_path(fi); i++) { 493 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 494 495 if (nhc->nhc_lwtstate) { 496 /* RTA_ENCAP_TYPE */ 497 nh_encapsize += lwtunnel_get_encap_size( 498 nhc->nhc_lwtstate); 499 /* RTA_ENCAP */ 500 nh_encapsize += nla_total_size(2); 501 } 502 } 503 504 /* all nexthops are packed in a nested attribute */ 505 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 506 507 } 508 509 return payload; 510 } 511 512 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 513 int dst_len, u32 tb_id, const struct nl_info *info, 514 unsigned int nlm_flags) 515 { 516 struct fib_rt_info fri; 517 struct sk_buff *skb; 518 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 519 int err = -ENOBUFS; 520 521 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 522 if (!skb) 523 goto errout; 524 525 fri.fi = fa->fa_info; 526 fri.tb_id = tb_id; 527 fri.dst = key; 528 fri.dst_len = dst_len; 529 fri.dscp = fa->fa_dscp; 530 fri.type = fa->fa_type; 531 fri.offload = READ_ONCE(fa->offload); 532 fri.trap = READ_ONCE(fa->trap); 533 fri.offload_failed = READ_ONCE(fa->offload_failed); 534 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 535 if (err < 0) { 536 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 537 WARN_ON(err == -EMSGSIZE); 538 kfree_skb(skb); 539 goto errout; 540 } 541 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 542 info->nlh, GFP_KERNEL); 543 return; 544 errout: 545 if (err < 0) 546 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 547 } 548 549 static int fib_detect_death(struct fib_info *fi, int order, 550 struct fib_info **last_resort, int *last_idx, 551 int dflt) 552 { 553 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 554 struct neighbour *n; 555 int state = NUD_NONE; 556 557 if (likely(nhc->nhc_gw_family == AF_INET)) 558 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 559 else if (nhc->nhc_gw_family == AF_INET6) 560 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 561 nhc->nhc_dev); 562 else 563 n = NULL; 564 565 if (n) { 566 state = READ_ONCE(n->nud_state); 567 neigh_release(n); 568 } else { 569 return 0; 570 } 571 if (state == NUD_REACHABLE) 572 return 0; 573 if ((state & NUD_VALID) && order != dflt) 574 return 0; 575 if ((state & NUD_VALID) || 576 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 577 *last_resort = fi; 578 *last_idx = order; 579 } 580 return 1; 581 } 582 583 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 584 struct nlattr *encap, u16 encap_type, 585 void *cfg, gfp_t gfp_flags, 586 struct netlink_ext_ack *extack) 587 { 588 int err; 589 590 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 591 gfp_flags); 592 if (!nhc->nhc_pcpu_rth_output) 593 return -ENOMEM; 594 595 if (encap) { 596 struct lwtunnel_state *lwtstate; 597 598 if (encap_type == LWTUNNEL_ENCAP_NONE) { 599 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 600 err = -EINVAL; 601 goto lwt_failure; 602 } 603 err = lwtunnel_build_state(net, encap_type, encap, 604 nhc->nhc_family, cfg, &lwtstate, 605 extack); 606 if (err) 607 goto lwt_failure; 608 609 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 610 } 611 612 return 0; 613 614 lwt_failure: 615 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 616 nhc->nhc_pcpu_rth_output = NULL; 617 return err; 618 } 619 EXPORT_SYMBOL_GPL(fib_nh_common_init); 620 621 int fib_nh_init(struct net *net, struct fib_nh *nh, 622 struct fib_config *cfg, int nh_weight, 623 struct netlink_ext_ack *extack) 624 { 625 int err; 626 627 nh->fib_nh_family = AF_INET; 628 629 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 630 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 631 if (err) 632 return err; 633 634 nh->fib_nh_oif = cfg->fc_oif; 635 nh->fib_nh_gw_family = cfg->fc_gw_family; 636 if (cfg->fc_gw_family == AF_INET) 637 nh->fib_nh_gw4 = cfg->fc_gw4; 638 else if (cfg->fc_gw_family == AF_INET6) 639 nh->fib_nh_gw6 = cfg->fc_gw6; 640 641 nh->fib_nh_flags = cfg->fc_flags; 642 643 #ifdef CONFIG_IP_ROUTE_CLASSID 644 nh->nh_tclassid = cfg->fc_flow; 645 if (nh->nh_tclassid) 646 atomic_inc(&net->ipv4.fib_num_tclassid_users); 647 #endif 648 #ifdef CONFIG_IP_ROUTE_MULTIPATH 649 nh->fib_nh_weight = nh_weight; 650 #endif 651 return 0; 652 } 653 654 #ifdef CONFIG_IP_ROUTE_MULTIPATH 655 656 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 657 struct netlink_ext_ack *extack) 658 { 659 int nhs = 0; 660 661 while (rtnh_ok(rtnh, remaining)) { 662 nhs++; 663 rtnh = rtnh_next(rtnh, &remaining); 664 } 665 666 /* leftover implies invalid nexthop configuration, discard it */ 667 if (remaining > 0) { 668 NL_SET_ERR_MSG(extack, 669 "Invalid nexthop configuration - extra data after nexthops"); 670 nhs = 0; 671 } 672 673 return nhs; 674 } 675 676 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 677 struct netlink_ext_ack *extack) 678 { 679 if (nla_len(nla) < sizeof(*gw)) { 680 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 681 return -EINVAL; 682 } 683 684 *gw = nla_get_in_addr(nla); 685 686 return 0; 687 } 688 689 /* only called when fib_nh is integrated into fib_info */ 690 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 691 int remaining, struct fib_config *cfg, 692 struct netlink_ext_ack *extack) 693 { 694 struct net *net = fi->fib_net; 695 struct fib_config fib_cfg; 696 struct fib_nh *nh; 697 int ret; 698 699 change_nexthops(fi) { 700 int attrlen; 701 702 memset(&fib_cfg, 0, sizeof(fib_cfg)); 703 704 if (!rtnh_ok(rtnh, remaining)) { 705 NL_SET_ERR_MSG(extack, 706 "Invalid nexthop configuration - extra data after nexthop"); 707 return -EINVAL; 708 } 709 710 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 711 NL_SET_ERR_MSG(extack, 712 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 713 return -EINVAL; 714 } 715 716 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 717 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 718 719 attrlen = rtnh_attrlen(rtnh); 720 if (attrlen > 0) { 721 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 722 723 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 724 nlav = nla_find(attrs, attrlen, RTA_VIA); 725 if (nla && nlav) { 726 NL_SET_ERR_MSG(extack, 727 "Nexthop configuration can not contain both GATEWAY and VIA"); 728 return -EINVAL; 729 } 730 if (nla) { 731 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 732 extack); 733 if (ret) 734 goto errout; 735 736 if (fib_cfg.fc_gw4) 737 fib_cfg.fc_gw_family = AF_INET; 738 } else if (nlav) { 739 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 740 if (ret) 741 goto errout; 742 } 743 744 nla = nla_find(attrs, attrlen, RTA_FLOW); 745 if (nla) { 746 if (nla_len(nla) < sizeof(u32)) { 747 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 748 return -EINVAL; 749 } 750 fib_cfg.fc_flow = nla_get_u32(nla); 751 } 752 753 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 754 /* RTA_ENCAP_TYPE length checked in 755 * lwtunnel_valid_encap_type_attr 756 */ 757 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 758 if (nla) 759 fib_cfg.fc_encap_type = nla_get_u16(nla); 760 } 761 762 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 763 rtnh->rtnh_hops + 1, extack); 764 if (ret) 765 goto errout; 766 767 rtnh = rtnh_next(rtnh, &remaining); 768 } endfor_nexthops(fi); 769 770 ret = -EINVAL; 771 nh = fib_info_nh(fi, 0); 772 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 773 NL_SET_ERR_MSG(extack, 774 "Nexthop device index does not match RTA_OIF"); 775 goto errout; 776 } 777 if (cfg->fc_gw_family) { 778 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 779 (cfg->fc_gw_family == AF_INET && 780 nh->fib_nh_gw4 != cfg->fc_gw4) || 781 (cfg->fc_gw_family == AF_INET6 && 782 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 783 NL_SET_ERR_MSG(extack, 784 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 785 goto errout; 786 } 787 } 788 #ifdef CONFIG_IP_ROUTE_CLASSID 789 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 790 NL_SET_ERR_MSG(extack, 791 "Nexthop class id does not match RTA_FLOW"); 792 goto errout; 793 } 794 #endif 795 ret = 0; 796 errout: 797 return ret; 798 } 799 800 /* only called when fib_nh is integrated into fib_info */ 801 static void fib_rebalance(struct fib_info *fi) 802 { 803 int total; 804 int w; 805 806 if (fib_info_num_path(fi) < 2) 807 return; 808 809 total = 0; 810 for_nexthops(fi) { 811 if (nh->fib_nh_flags & RTNH_F_DEAD) 812 continue; 813 814 if (ip_ignore_linkdown(nh->fib_nh_dev) && 815 nh->fib_nh_flags & RTNH_F_LINKDOWN) 816 continue; 817 818 total += nh->fib_nh_weight; 819 } endfor_nexthops(fi); 820 821 w = 0; 822 change_nexthops(fi) { 823 int upper_bound; 824 825 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 826 upper_bound = -1; 827 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 828 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 829 upper_bound = -1; 830 } else { 831 w += nexthop_nh->fib_nh_weight; 832 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 833 total) - 1; 834 } 835 836 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 837 } endfor_nexthops(fi); 838 } 839 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 840 841 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 842 int remaining, struct fib_config *cfg, 843 struct netlink_ext_ack *extack) 844 { 845 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 846 847 return -EINVAL; 848 } 849 850 #define fib_rebalance(fi) do { } while (0) 851 852 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 853 854 static int fib_encap_match(struct net *net, u16 encap_type, 855 struct nlattr *encap, 856 const struct fib_nh *nh, 857 const struct fib_config *cfg, 858 struct netlink_ext_ack *extack) 859 { 860 struct lwtunnel_state *lwtstate; 861 int ret, result = 0; 862 863 if (encap_type == LWTUNNEL_ENCAP_NONE) 864 return 0; 865 866 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 867 cfg, &lwtstate, extack); 868 if (!ret) { 869 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 870 lwtstate_free(lwtstate); 871 } 872 873 return result; 874 } 875 876 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 877 struct netlink_ext_ack *extack) 878 { 879 #ifdef CONFIG_IP_ROUTE_MULTIPATH 880 struct rtnexthop *rtnh; 881 int remaining; 882 #endif 883 884 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 885 return 1; 886 887 if (cfg->fc_nh_id) { 888 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 889 return 0; 890 return 1; 891 } 892 893 if (fi->nh) { 894 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 895 return 1; 896 return 0; 897 } 898 899 if (cfg->fc_oif || cfg->fc_gw_family) { 900 struct fib_nh *nh; 901 902 nh = fib_info_nh(fi, 0); 903 if (cfg->fc_encap) { 904 if (fib_encap_match(net, cfg->fc_encap_type, 905 cfg->fc_encap, nh, cfg, extack)) 906 return 1; 907 } 908 #ifdef CONFIG_IP_ROUTE_CLASSID 909 if (cfg->fc_flow && 910 cfg->fc_flow != nh->nh_tclassid) 911 return 1; 912 #endif 913 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 914 (cfg->fc_gw_family && 915 cfg->fc_gw_family != nh->fib_nh_gw_family)) 916 return 1; 917 918 if (cfg->fc_gw_family == AF_INET && 919 cfg->fc_gw4 != nh->fib_nh_gw4) 920 return 1; 921 922 if (cfg->fc_gw_family == AF_INET6 && 923 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 924 return 1; 925 926 return 0; 927 } 928 929 #ifdef CONFIG_IP_ROUTE_MULTIPATH 930 if (!cfg->fc_mp) 931 return 0; 932 933 rtnh = cfg->fc_mp; 934 remaining = cfg->fc_mp_len; 935 936 for_nexthops(fi) { 937 int attrlen; 938 939 if (!rtnh_ok(rtnh, remaining)) 940 return -EINVAL; 941 942 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 943 return 1; 944 945 attrlen = rtnh_attrlen(rtnh); 946 if (attrlen > 0) { 947 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 948 int err; 949 950 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 951 nlav = nla_find(attrs, attrlen, RTA_VIA); 952 if (nla && nlav) { 953 NL_SET_ERR_MSG(extack, 954 "Nexthop configuration can not contain both GATEWAY and VIA"); 955 return -EINVAL; 956 } 957 958 if (nla) { 959 __be32 gw; 960 961 err = fib_gw_from_attr(&gw, nla, extack); 962 if (err) 963 return err; 964 965 if (nh->fib_nh_gw_family != AF_INET || 966 gw != nh->fib_nh_gw4) 967 return 1; 968 } else if (nlav) { 969 struct fib_config cfg2; 970 971 err = fib_gw_from_via(&cfg2, nlav, extack); 972 if (err) 973 return err; 974 975 switch (nh->fib_nh_gw_family) { 976 case AF_INET: 977 if (cfg2.fc_gw_family != AF_INET || 978 cfg2.fc_gw4 != nh->fib_nh_gw4) 979 return 1; 980 break; 981 case AF_INET6: 982 if (cfg2.fc_gw_family != AF_INET6 || 983 ipv6_addr_cmp(&cfg2.fc_gw6, 984 &nh->fib_nh_gw6)) 985 return 1; 986 break; 987 } 988 } 989 990 #ifdef CONFIG_IP_ROUTE_CLASSID 991 nla = nla_find(attrs, attrlen, RTA_FLOW); 992 if (nla) { 993 if (nla_len(nla) < sizeof(u32)) { 994 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 995 return -EINVAL; 996 } 997 if (nla_get_u32(nla) != nh->nh_tclassid) 998 return 1; 999 } 1000 #endif 1001 } 1002 1003 rtnh = rtnh_next(rtnh, &remaining); 1004 } endfor_nexthops(fi); 1005 #endif 1006 return 0; 1007 } 1008 1009 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1010 { 1011 struct nlattr *nla; 1012 int remaining; 1013 1014 if (!cfg->fc_mx) 1015 return true; 1016 1017 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1018 int type = nla_type(nla); 1019 u32 fi_val, val; 1020 1021 if (!type) 1022 continue; 1023 if (type > RTAX_MAX) 1024 return false; 1025 1026 type = array_index_nospec(type, RTAX_MAX + 1); 1027 if (type == RTAX_CC_ALGO) { 1028 char tmp[TCP_CA_NAME_MAX]; 1029 bool ecn_ca = false; 1030 1031 nla_strscpy(tmp, nla, sizeof(tmp)); 1032 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1033 } else { 1034 if (nla_len(nla) != sizeof(u32)) 1035 return false; 1036 val = nla_get_u32(nla); 1037 } 1038 1039 fi_val = fi->fib_metrics->metrics[type - 1]; 1040 if (type == RTAX_FEATURES) 1041 fi_val &= ~DST_FEATURE_ECN_CA; 1042 1043 if (fi_val != val) 1044 return false; 1045 } 1046 1047 return true; 1048 } 1049 1050 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1051 u32 table, struct netlink_ext_ack *extack) 1052 { 1053 struct fib6_config cfg = { 1054 .fc_table = table, 1055 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1056 .fc_ifindex = nh->fib_nh_oif, 1057 .fc_gateway = nh->fib_nh_gw6, 1058 }; 1059 struct fib6_nh fib6_nh = {}; 1060 int err; 1061 1062 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1063 if (!err) { 1064 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1065 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1066 GFP_KERNEL); 1067 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1068 nh->fib_nh_scope = RT_SCOPE_LINK; 1069 1070 ipv6_stub->fib6_nh_release(&fib6_nh); 1071 } 1072 1073 return err; 1074 } 1075 1076 /* 1077 * Picture 1078 * ------- 1079 * 1080 * Semantics of nexthop is very messy by historical reasons. 1081 * We have to take into account, that: 1082 * a) gateway can be actually local interface address, 1083 * so that gatewayed route is direct. 1084 * b) gateway must be on-link address, possibly 1085 * described not by an ifaddr, but also by a direct route. 1086 * c) If both gateway and interface are specified, they should not 1087 * contradict. 1088 * d) If we use tunnel routes, gateway could be not on-link. 1089 * 1090 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1091 * results in pretty ugly and hairy code with obscure logic. 1092 * 1093 * I chose to generalized it instead, so that the size 1094 * of code does not increase practically, but it becomes 1095 * much more general. 1096 * Every prefix is assigned a "scope" value: "host" is local address, 1097 * "link" is direct route, 1098 * [ ... "site" ... "interior" ... ] 1099 * and "universe" is true gateway route with global meaning. 1100 * 1101 * Every prefix refers to a set of "nexthop"s (gw, oif), 1102 * where gw must have narrower scope. This recursion stops 1103 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1104 * which means that gw is forced to be on link. 1105 * 1106 * Code is still hairy, but now it is apparently logically 1107 * consistent and very flexible. F.e. as by-product it allows 1108 * to co-exists in peace independent exterior and interior 1109 * routing processes. 1110 * 1111 * Normally it looks as following. 1112 * 1113 * {universe prefix} -> (gw, oif) [scope link] 1114 * | 1115 * |-> {link prefix} -> (gw, oif) [scope local] 1116 * | 1117 * |-> {local prefix} (terminal node) 1118 */ 1119 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1120 u8 scope, struct netlink_ext_ack *extack) 1121 { 1122 struct net_device *dev; 1123 struct fib_result res; 1124 int err = 0; 1125 1126 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1127 unsigned int addr_type; 1128 1129 if (scope >= RT_SCOPE_LINK) { 1130 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1131 return -EINVAL; 1132 } 1133 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1134 if (!dev) { 1135 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1136 return -ENODEV; 1137 } 1138 if (!(dev->flags & IFF_UP)) { 1139 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1140 return -ENETDOWN; 1141 } 1142 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1143 if (addr_type != RTN_UNICAST) { 1144 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1145 return -EINVAL; 1146 } 1147 if (!netif_carrier_ok(dev)) 1148 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1149 nh->fib_nh_dev = dev; 1150 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1151 nh->fib_nh_scope = RT_SCOPE_LINK; 1152 return 0; 1153 } 1154 rcu_read_lock(); 1155 { 1156 struct fib_table *tbl = NULL; 1157 struct flowi4 fl4 = { 1158 .daddr = nh->fib_nh_gw4, 1159 .flowi4_scope = scope + 1, 1160 .flowi4_oif = nh->fib_nh_oif, 1161 .flowi4_iif = LOOPBACK_IFINDEX, 1162 }; 1163 1164 /* It is not necessary, but requires a bit of thinking */ 1165 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1166 fl4.flowi4_scope = RT_SCOPE_LINK; 1167 1168 if (table && table != RT_TABLE_MAIN) 1169 tbl = fib_get_table(net, table); 1170 1171 if (tbl) 1172 err = fib_table_lookup(tbl, &fl4, &res, 1173 FIB_LOOKUP_IGNORE_LINKSTATE | 1174 FIB_LOOKUP_NOREF); 1175 1176 /* on error or if no table given do full lookup. This 1177 * is needed for example when nexthops are in the local 1178 * table rather than the given table 1179 */ 1180 if (!tbl || err) { 1181 err = fib_lookup(net, &fl4, &res, 1182 FIB_LOOKUP_IGNORE_LINKSTATE); 1183 } 1184 1185 if (err) { 1186 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1187 goto out; 1188 } 1189 } 1190 1191 err = -EINVAL; 1192 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1193 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1194 goto out; 1195 } 1196 nh->fib_nh_scope = res.scope; 1197 nh->fib_nh_oif = FIB_RES_OIF(res); 1198 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1199 if (!dev) { 1200 NL_SET_ERR_MSG(extack, 1201 "No egress device for nexthop gateway"); 1202 goto out; 1203 } 1204 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1205 if (!netif_carrier_ok(dev)) 1206 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1207 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1208 out: 1209 rcu_read_unlock(); 1210 return err; 1211 } 1212 1213 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1214 struct netlink_ext_ack *extack) 1215 { 1216 struct in_device *in_dev; 1217 int err; 1218 1219 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1220 NL_SET_ERR_MSG(extack, 1221 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1222 return -EINVAL; 1223 } 1224 1225 rcu_read_lock(); 1226 1227 err = -ENODEV; 1228 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1229 if (!in_dev) 1230 goto out; 1231 err = -ENETDOWN; 1232 if (!(in_dev->dev->flags & IFF_UP)) { 1233 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1234 goto out; 1235 } 1236 1237 nh->fib_nh_dev = in_dev->dev; 1238 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1239 nh->fib_nh_scope = RT_SCOPE_HOST; 1240 if (!netif_carrier_ok(nh->fib_nh_dev)) 1241 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1242 err = 0; 1243 out: 1244 rcu_read_unlock(); 1245 return err; 1246 } 1247 1248 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1249 struct netlink_ext_ack *extack) 1250 { 1251 int err; 1252 1253 if (nh->fib_nh_gw_family == AF_INET) 1254 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1255 else if (nh->fib_nh_gw_family == AF_INET6) 1256 err = fib_check_nh_v6_gw(net, nh, table, extack); 1257 else 1258 err = fib_check_nh_nongw(net, nh, extack); 1259 1260 return err; 1261 } 1262 1263 static struct hlist_head * 1264 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1265 { 1266 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1267 fib_info_hash_bits); 1268 1269 return &fib_info_laddrhash[slot]; 1270 } 1271 1272 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1273 struct hlist_head *new_laddrhash, 1274 unsigned int new_size) 1275 { 1276 struct hlist_head *old_info_hash, *old_laddrhash; 1277 unsigned int old_size = fib_info_hash_size; 1278 unsigned int i; 1279 1280 spin_lock_bh(&fib_info_lock); 1281 old_info_hash = fib_info_hash; 1282 old_laddrhash = fib_info_laddrhash; 1283 fib_info_hash_size = new_size; 1284 fib_info_hash_bits = ilog2(new_size); 1285 1286 for (i = 0; i < old_size; i++) { 1287 struct hlist_head *head = &fib_info_hash[i]; 1288 struct hlist_node *n; 1289 struct fib_info *fi; 1290 1291 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1292 struct hlist_head *dest; 1293 unsigned int new_hash; 1294 1295 new_hash = fib_info_hashfn(fi); 1296 dest = &new_info_hash[new_hash]; 1297 hlist_add_head(&fi->fib_hash, dest); 1298 } 1299 } 1300 fib_info_hash = new_info_hash; 1301 1302 fib_info_laddrhash = new_laddrhash; 1303 for (i = 0; i < old_size; i++) { 1304 struct hlist_head *lhead = &old_laddrhash[i]; 1305 struct hlist_node *n; 1306 struct fib_info *fi; 1307 1308 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1309 struct hlist_head *ldest; 1310 1311 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1312 fi->fib_prefsrc); 1313 hlist_add_head(&fi->fib_lhash, ldest); 1314 } 1315 } 1316 1317 spin_unlock_bh(&fib_info_lock); 1318 1319 kvfree(old_info_hash); 1320 kvfree(old_laddrhash); 1321 } 1322 1323 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1324 unsigned char scope) 1325 { 1326 struct fib_nh *nh; 1327 1328 if (nhc->nhc_family != AF_INET) 1329 return inet_select_addr(nhc->nhc_dev, 0, scope); 1330 1331 nh = container_of(nhc, struct fib_nh, nh_common); 1332 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1333 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1334 1335 return nh->nh_saddr; 1336 } 1337 1338 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1339 { 1340 struct fib_nh_common *nhc = res->nhc; 1341 1342 if (res->fi->fib_prefsrc) 1343 return res->fi->fib_prefsrc; 1344 1345 if (nhc->nhc_family == AF_INET) { 1346 struct fib_nh *nh; 1347 1348 nh = container_of(nhc, struct fib_nh, nh_common); 1349 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1350 return nh->nh_saddr; 1351 } 1352 1353 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1354 } 1355 1356 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1357 { 1358 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1359 fib_prefsrc != cfg->fc_dst) { 1360 u32 tb_id = cfg->fc_table; 1361 int rc; 1362 1363 if (tb_id == RT_TABLE_MAIN) 1364 tb_id = RT_TABLE_LOCAL; 1365 1366 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1367 fib_prefsrc, tb_id); 1368 1369 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1370 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1371 fib_prefsrc, RT_TABLE_LOCAL); 1372 } 1373 1374 if (rc != RTN_LOCAL) 1375 return false; 1376 } 1377 return true; 1378 } 1379 1380 struct fib_info *fib_create_info(struct fib_config *cfg, 1381 struct netlink_ext_ack *extack) 1382 { 1383 int err; 1384 struct fib_info *fi = NULL; 1385 struct nexthop *nh = NULL; 1386 struct fib_info *ofi; 1387 int nhs = 1; 1388 struct net *net = cfg->fc_nlinfo.nl_net; 1389 1390 if (cfg->fc_type > RTN_MAX) 1391 goto err_inval; 1392 1393 /* Fast check to catch the most weird cases */ 1394 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1395 NL_SET_ERR_MSG(extack, "Invalid scope"); 1396 goto err_inval; 1397 } 1398 1399 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1400 NL_SET_ERR_MSG(extack, 1401 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1402 goto err_inval; 1403 } 1404 1405 if (cfg->fc_nh_id) { 1406 if (!cfg->fc_mx) { 1407 fi = fib_find_info_nh(net, cfg); 1408 if (fi) { 1409 refcount_inc(&fi->fib_treeref); 1410 return fi; 1411 } 1412 } 1413 1414 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1415 if (!nh) { 1416 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1417 goto err_inval; 1418 } 1419 nhs = 0; 1420 } 1421 1422 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1423 if (cfg->fc_mp) { 1424 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1425 if (nhs == 0) 1426 goto err_inval; 1427 } 1428 #endif 1429 1430 err = -ENOBUFS; 1431 1432 /* Paired with WRITE_ONCE() in fib_release_info() */ 1433 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1434 unsigned int new_size = fib_info_hash_size << 1; 1435 struct hlist_head *new_info_hash; 1436 struct hlist_head *new_laddrhash; 1437 size_t bytes; 1438 1439 if (!new_size) 1440 new_size = 16; 1441 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1442 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1443 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1444 if (!new_info_hash || !new_laddrhash) { 1445 kvfree(new_info_hash); 1446 kvfree(new_laddrhash); 1447 } else { 1448 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1449 } 1450 if (!fib_info_hash_size) 1451 goto failure; 1452 } 1453 1454 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1455 if (!fi) 1456 goto failure; 1457 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1458 cfg->fc_mx_len, extack); 1459 if (IS_ERR(fi->fib_metrics)) { 1460 err = PTR_ERR(fi->fib_metrics); 1461 kfree(fi); 1462 return ERR_PTR(err); 1463 } 1464 1465 fi->fib_net = net; 1466 fi->fib_protocol = cfg->fc_protocol; 1467 fi->fib_scope = cfg->fc_scope; 1468 fi->fib_flags = cfg->fc_flags; 1469 fi->fib_priority = cfg->fc_priority; 1470 fi->fib_prefsrc = cfg->fc_prefsrc; 1471 fi->fib_type = cfg->fc_type; 1472 fi->fib_tb_id = cfg->fc_table; 1473 1474 fi->fib_nhs = nhs; 1475 if (nh) { 1476 if (!nexthop_get(nh)) { 1477 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1478 err = -EINVAL; 1479 } else { 1480 err = 0; 1481 fi->nh = nh; 1482 } 1483 } else { 1484 change_nexthops(fi) { 1485 nexthop_nh->nh_parent = fi; 1486 } endfor_nexthops(fi) 1487 1488 if (cfg->fc_mp) 1489 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1490 extack); 1491 else 1492 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1493 } 1494 1495 if (err != 0) 1496 goto failure; 1497 1498 if (fib_props[cfg->fc_type].error) { 1499 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1500 NL_SET_ERR_MSG(extack, 1501 "Gateway, device and multipath can not be specified for this route type"); 1502 goto err_inval; 1503 } 1504 goto link_it; 1505 } else { 1506 switch (cfg->fc_type) { 1507 case RTN_UNICAST: 1508 case RTN_LOCAL: 1509 case RTN_BROADCAST: 1510 case RTN_ANYCAST: 1511 case RTN_MULTICAST: 1512 break; 1513 default: 1514 NL_SET_ERR_MSG(extack, "Invalid route type"); 1515 goto err_inval; 1516 } 1517 } 1518 1519 if (cfg->fc_scope > RT_SCOPE_HOST) { 1520 NL_SET_ERR_MSG(extack, "Invalid scope"); 1521 goto err_inval; 1522 } 1523 1524 if (fi->nh) { 1525 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1526 if (err) 1527 goto failure; 1528 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1529 struct fib_nh *nh = fi->fib_nh; 1530 1531 /* Local address is added. */ 1532 if (nhs != 1) { 1533 NL_SET_ERR_MSG(extack, 1534 "Route with host scope can not have multiple nexthops"); 1535 goto err_inval; 1536 } 1537 if (nh->fib_nh_gw_family) { 1538 NL_SET_ERR_MSG(extack, 1539 "Route with host scope can not have a gateway"); 1540 goto err_inval; 1541 } 1542 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1543 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1544 err = -ENODEV; 1545 if (!nh->fib_nh_dev) 1546 goto failure; 1547 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1548 GFP_KERNEL); 1549 } else { 1550 int linkdown = 0; 1551 1552 change_nexthops(fi) { 1553 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1554 cfg->fc_table, cfg->fc_scope, 1555 extack); 1556 if (err != 0) 1557 goto failure; 1558 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1559 linkdown++; 1560 } endfor_nexthops(fi) 1561 if (linkdown == fi->fib_nhs) 1562 fi->fib_flags |= RTNH_F_LINKDOWN; 1563 } 1564 1565 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1566 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1567 goto err_inval; 1568 } 1569 1570 if (!fi->nh) { 1571 change_nexthops(fi) { 1572 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1573 fi->fib_scope); 1574 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1575 fi->fib_nh_is_v6 = true; 1576 } endfor_nexthops(fi) 1577 1578 fib_rebalance(fi); 1579 } 1580 1581 link_it: 1582 ofi = fib_find_info(fi); 1583 if (ofi) { 1584 fi->fib_dead = 1; 1585 free_fib_info(fi); 1586 refcount_inc(&ofi->fib_treeref); 1587 return ofi; 1588 } 1589 1590 refcount_set(&fi->fib_treeref, 1); 1591 refcount_set(&fi->fib_clntref, 1); 1592 spin_lock_bh(&fib_info_lock); 1593 fib_info_cnt++; 1594 hlist_add_head(&fi->fib_hash, 1595 &fib_info_hash[fib_info_hashfn(fi)]); 1596 if (fi->fib_prefsrc) { 1597 struct hlist_head *head; 1598 1599 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1600 hlist_add_head(&fi->fib_lhash, head); 1601 } 1602 if (fi->nh) { 1603 list_add(&fi->nh_list, &nh->fi_list); 1604 } else { 1605 change_nexthops(fi) { 1606 struct hlist_head *head; 1607 1608 if (!nexthop_nh->fib_nh_dev) 1609 continue; 1610 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1611 hlist_add_head(&nexthop_nh->nh_hash, head); 1612 } endfor_nexthops(fi) 1613 } 1614 spin_unlock_bh(&fib_info_lock); 1615 return fi; 1616 1617 err_inval: 1618 err = -EINVAL; 1619 1620 failure: 1621 if (fi) { 1622 fi->fib_dead = 1; 1623 free_fib_info(fi); 1624 } 1625 1626 return ERR_PTR(err); 1627 } 1628 1629 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1630 u8 rt_family, unsigned char *flags, bool skip_oif) 1631 { 1632 if (nhc->nhc_flags & RTNH_F_DEAD) 1633 *flags |= RTNH_F_DEAD; 1634 1635 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1636 *flags |= RTNH_F_LINKDOWN; 1637 1638 rcu_read_lock(); 1639 switch (nhc->nhc_family) { 1640 case AF_INET: 1641 if (ip_ignore_linkdown(nhc->nhc_dev)) 1642 *flags |= RTNH_F_DEAD; 1643 break; 1644 case AF_INET6: 1645 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1646 *flags |= RTNH_F_DEAD; 1647 break; 1648 } 1649 rcu_read_unlock(); 1650 } 1651 1652 switch (nhc->nhc_gw_family) { 1653 case AF_INET: 1654 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1655 goto nla_put_failure; 1656 break; 1657 case AF_INET6: 1658 /* if gateway family does not match nexthop family 1659 * gateway is encoded as RTA_VIA 1660 */ 1661 if (rt_family != nhc->nhc_gw_family) { 1662 int alen = sizeof(struct in6_addr); 1663 struct nlattr *nla; 1664 struct rtvia *via; 1665 1666 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1667 if (!nla) 1668 goto nla_put_failure; 1669 1670 via = nla_data(nla); 1671 via->rtvia_family = AF_INET6; 1672 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1673 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1674 &nhc->nhc_gw.ipv6) < 0) { 1675 goto nla_put_failure; 1676 } 1677 break; 1678 } 1679 1680 *flags |= (nhc->nhc_flags & 1681 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1682 1683 if (!skip_oif && nhc->nhc_dev && 1684 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1685 goto nla_put_failure; 1686 1687 if (nhc->nhc_lwtstate && 1688 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1689 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1690 goto nla_put_failure; 1691 1692 return 0; 1693 1694 nla_put_failure: 1695 return -EMSGSIZE; 1696 } 1697 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1698 1699 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1700 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1701 int nh_weight, u8 rt_family, u32 nh_tclassid) 1702 { 1703 const struct net_device *dev = nhc->nhc_dev; 1704 struct rtnexthop *rtnh; 1705 unsigned char flags = 0; 1706 1707 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1708 if (!rtnh) 1709 goto nla_put_failure; 1710 1711 rtnh->rtnh_hops = nh_weight - 1; 1712 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1713 1714 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1715 goto nla_put_failure; 1716 1717 rtnh->rtnh_flags = flags; 1718 1719 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1720 goto nla_put_failure; 1721 1722 /* length of rtnetlink header + attributes */ 1723 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1724 1725 return 0; 1726 1727 nla_put_failure: 1728 return -EMSGSIZE; 1729 } 1730 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1731 #endif 1732 1733 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1734 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1735 { 1736 struct nlattr *mp; 1737 1738 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1739 if (!mp) 1740 goto nla_put_failure; 1741 1742 if (unlikely(fi->nh)) { 1743 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1744 goto nla_put_failure; 1745 goto mp_end; 1746 } 1747 1748 for_nexthops(fi) { 1749 u32 nh_tclassid = 0; 1750 #ifdef CONFIG_IP_ROUTE_CLASSID 1751 nh_tclassid = nh->nh_tclassid; 1752 #endif 1753 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1754 AF_INET, nh_tclassid) < 0) 1755 goto nla_put_failure; 1756 } endfor_nexthops(fi); 1757 1758 mp_end: 1759 nla_nest_end(skb, mp); 1760 1761 return 0; 1762 1763 nla_put_failure: 1764 return -EMSGSIZE; 1765 } 1766 #else 1767 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1768 { 1769 return 0; 1770 } 1771 #endif 1772 1773 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1774 const struct fib_rt_info *fri, unsigned int flags) 1775 { 1776 unsigned int nhs = fib_info_num_path(fri->fi); 1777 struct fib_info *fi = fri->fi; 1778 u32 tb_id = fri->tb_id; 1779 struct nlmsghdr *nlh; 1780 struct rtmsg *rtm; 1781 1782 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1783 if (!nlh) 1784 return -EMSGSIZE; 1785 1786 rtm = nlmsg_data(nlh); 1787 rtm->rtm_family = AF_INET; 1788 rtm->rtm_dst_len = fri->dst_len; 1789 rtm->rtm_src_len = 0; 1790 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); 1791 if (tb_id < 256) 1792 rtm->rtm_table = tb_id; 1793 else 1794 rtm->rtm_table = RT_TABLE_COMPAT; 1795 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1796 goto nla_put_failure; 1797 rtm->rtm_type = fri->type; 1798 rtm->rtm_flags = fi->fib_flags; 1799 rtm->rtm_scope = fi->fib_scope; 1800 rtm->rtm_protocol = fi->fib_protocol; 1801 1802 if (rtm->rtm_dst_len && 1803 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1804 goto nla_put_failure; 1805 if (fi->fib_priority && 1806 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1807 goto nla_put_failure; 1808 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1809 goto nla_put_failure; 1810 1811 if (fi->fib_prefsrc && 1812 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1813 goto nla_put_failure; 1814 1815 if (fi->nh) { 1816 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1817 goto nla_put_failure; 1818 if (nexthop_is_blackhole(fi->nh)) 1819 rtm->rtm_type = RTN_BLACKHOLE; 1820 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1821 goto offload; 1822 } 1823 1824 if (nhs == 1) { 1825 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1826 unsigned char flags = 0; 1827 1828 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1829 goto nla_put_failure; 1830 1831 rtm->rtm_flags = flags; 1832 #ifdef CONFIG_IP_ROUTE_CLASSID 1833 if (nhc->nhc_family == AF_INET) { 1834 struct fib_nh *nh; 1835 1836 nh = container_of(nhc, struct fib_nh, nh_common); 1837 if (nh->nh_tclassid && 1838 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1839 goto nla_put_failure; 1840 } 1841 #endif 1842 } else { 1843 if (fib_add_multipath(skb, fi) < 0) 1844 goto nla_put_failure; 1845 } 1846 1847 offload: 1848 if (fri->offload) 1849 rtm->rtm_flags |= RTM_F_OFFLOAD; 1850 if (fri->trap) 1851 rtm->rtm_flags |= RTM_F_TRAP; 1852 if (fri->offload_failed) 1853 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1854 1855 nlmsg_end(skb, nlh); 1856 return 0; 1857 1858 nla_put_failure: 1859 nlmsg_cancel(skb, nlh); 1860 return -EMSGSIZE; 1861 } 1862 1863 /* 1864 * Update FIB if: 1865 * - local address disappeared -> we must delete all the entries 1866 * referring to it. 1867 * - device went down -> we must shutdown all nexthops going via it. 1868 */ 1869 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1870 { 1871 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1872 struct net *net = dev_net(dev); 1873 struct hlist_head *head; 1874 struct fib_info *fi; 1875 int ret = 0; 1876 1877 if (!fib_info_laddrhash || local == 0) 1878 return 0; 1879 1880 head = fib_info_laddrhash_bucket(net, local); 1881 hlist_for_each_entry(fi, head, fib_lhash) { 1882 if (!net_eq(fi->fib_net, net) || 1883 fi->fib_tb_id != tb_id) 1884 continue; 1885 if (fi->fib_prefsrc == local) { 1886 fi->fib_flags |= RTNH_F_DEAD; 1887 ret++; 1888 } 1889 } 1890 return ret; 1891 } 1892 1893 static int call_fib_nh_notifiers(struct fib_nh *nh, 1894 enum fib_event_type event_type) 1895 { 1896 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1897 struct fib_nh_notifier_info info = { 1898 .fib_nh = nh, 1899 }; 1900 1901 switch (event_type) { 1902 case FIB_EVENT_NH_ADD: 1903 if (nh->fib_nh_flags & RTNH_F_DEAD) 1904 break; 1905 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1906 break; 1907 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1908 &info.info); 1909 case FIB_EVENT_NH_DEL: 1910 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1911 (nh->fib_nh_flags & RTNH_F_DEAD)) 1912 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1913 event_type, &info.info); 1914 break; 1915 default: 1916 break; 1917 } 1918 1919 return NOTIFY_DONE; 1920 } 1921 1922 /* Update the PMTU of exceptions when: 1923 * - the new MTU of the first hop becomes smaller than the PMTU 1924 * - the old MTU was the same as the PMTU, and it limited discovery of 1925 * larger MTUs on the path. With that limit raised, we can now 1926 * discover larger MTUs 1927 * A special case is locked exceptions, for which the PMTU is smaller 1928 * than the minimal accepted PMTU: 1929 * - if the new MTU is greater than the PMTU, don't make any change 1930 * - otherwise, unlock and set PMTU 1931 */ 1932 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1933 { 1934 struct fnhe_hash_bucket *bucket; 1935 int i; 1936 1937 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1938 if (!bucket) 1939 return; 1940 1941 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1942 struct fib_nh_exception *fnhe; 1943 1944 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1945 fnhe; 1946 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1947 if (fnhe->fnhe_mtu_locked) { 1948 if (new <= fnhe->fnhe_pmtu) { 1949 fnhe->fnhe_pmtu = new; 1950 fnhe->fnhe_mtu_locked = false; 1951 } 1952 } else if (new < fnhe->fnhe_pmtu || 1953 orig == fnhe->fnhe_pmtu) { 1954 fnhe->fnhe_pmtu = new; 1955 } 1956 } 1957 } 1958 } 1959 1960 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1961 { 1962 struct hlist_head *head = fib_info_devhash_bucket(dev); 1963 struct fib_nh *nh; 1964 1965 hlist_for_each_entry(nh, head, nh_hash) { 1966 if (nh->fib_nh_dev == dev) 1967 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1968 } 1969 } 1970 1971 /* Event force Flags Description 1972 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1973 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1974 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1975 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1976 * 1977 * only used when fib_nh is built into fib_info 1978 */ 1979 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1980 { 1981 struct hlist_head *head = fib_info_devhash_bucket(dev); 1982 struct fib_info *prev_fi = NULL; 1983 int scope = RT_SCOPE_NOWHERE; 1984 struct fib_nh *nh; 1985 int ret = 0; 1986 1987 if (force) 1988 scope = -1; 1989 1990 hlist_for_each_entry(nh, head, nh_hash) { 1991 struct fib_info *fi = nh->nh_parent; 1992 int dead; 1993 1994 BUG_ON(!fi->fib_nhs); 1995 if (nh->fib_nh_dev != dev || fi == prev_fi) 1996 continue; 1997 prev_fi = fi; 1998 dead = 0; 1999 change_nexthops(fi) { 2000 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2001 dead++; 2002 else if (nexthop_nh->fib_nh_dev == dev && 2003 nexthop_nh->fib_nh_scope != scope) { 2004 switch (event) { 2005 case NETDEV_DOWN: 2006 case NETDEV_UNREGISTER: 2007 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2008 fallthrough; 2009 case NETDEV_CHANGE: 2010 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2011 break; 2012 } 2013 call_fib_nh_notifiers(nexthop_nh, 2014 FIB_EVENT_NH_DEL); 2015 dead++; 2016 } 2017 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2018 if (event == NETDEV_UNREGISTER && 2019 nexthop_nh->fib_nh_dev == dev) { 2020 dead = fi->fib_nhs; 2021 break; 2022 } 2023 #endif 2024 } endfor_nexthops(fi) 2025 if (dead == fi->fib_nhs) { 2026 switch (event) { 2027 case NETDEV_DOWN: 2028 case NETDEV_UNREGISTER: 2029 fi->fib_flags |= RTNH_F_DEAD; 2030 fallthrough; 2031 case NETDEV_CHANGE: 2032 fi->fib_flags |= RTNH_F_LINKDOWN; 2033 break; 2034 } 2035 ret++; 2036 } 2037 2038 fib_rebalance(fi); 2039 } 2040 2041 return ret; 2042 } 2043 2044 /* Must be invoked inside of an RCU protected region. */ 2045 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2046 { 2047 struct fib_info *fi = NULL, *last_resort = NULL; 2048 struct hlist_head *fa_head = res->fa_head; 2049 struct fib_table *tb = res->table; 2050 u8 slen = 32 - res->prefixlen; 2051 int order = -1, last_idx = -1; 2052 struct fib_alias *fa, *fa1 = NULL; 2053 u32 last_prio = res->fi->fib_priority; 2054 dscp_t last_dscp = 0; 2055 2056 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2057 struct fib_info *next_fi = fa->fa_info; 2058 struct fib_nh_common *nhc; 2059 2060 if (fa->fa_slen != slen) 2061 continue; 2062 if (fa->fa_dscp && 2063 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos)) 2064 continue; 2065 if (fa->tb_id != tb->tb_id) 2066 continue; 2067 if (next_fi->fib_priority > last_prio && 2068 fa->fa_dscp == last_dscp) { 2069 if (last_dscp) 2070 continue; 2071 break; 2072 } 2073 if (next_fi->fib_flags & RTNH_F_DEAD) 2074 continue; 2075 last_dscp = fa->fa_dscp; 2076 last_prio = next_fi->fib_priority; 2077 2078 if (next_fi->fib_scope != res->scope || 2079 fa->fa_type != RTN_UNICAST) 2080 continue; 2081 2082 nhc = fib_info_nhc(next_fi, 0); 2083 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2084 continue; 2085 2086 fib_alias_accessed(fa); 2087 2088 if (!fi) { 2089 if (next_fi != res->fi) 2090 break; 2091 fa1 = fa; 2092 } else if (!fib_detect_death(fi, order, &last_resort, 2093 &last_idx, fa1->fa_default)) { 2094 fib_result_assign(res, fi); 2095 fa1->fa_default = order; 2096 goto out; 2097 } 2098 fi = next_fi; 2099 order++; 2100 } 2101 2102 if (order <= 0 || !fi) { 2103 if (fa1) 2104 fa1->fa_default = -1; 2105 goto out; 2106 } 2107 2108 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2109 fa1->fa_default)) { 2110 fib_result_assign(res, fi); 2111 fa1->fa_default = order; 2112 goto out; 2113 } 2114 2115 if (last_idx >= 0) 2116 fib_result_assign(res, last_resort); 2117 fa1->fa_default = last_idx; 2118 out: 2119 return; 2120 } 2121 2122 /* 2123 * Dead device goes up. We wake up dead nexthops. 2124 * It takes sense only on multipath routes. 2125 * 2126 * only used when fib_nh is built into fib_info 2127 */ 2128 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2129 { 2130 struct fib_info *prev_fi; 2131 struct hlist_head *head; 2132 struct fib_nh *nh; 2133 int ret; 2134 2135 if (!(dev->flags & IFF_UP)) 2136 return 0; 2137 2138 if (nh_flags & RTNH_F_DEAD) { 2139 unsigned int flags = dev_get_flags(dev); 2140 2141 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2142 nh_flags |= RTNH_F_LINKDOWN; 2143 } 2144 2145 prev_fi = NULL; 2146 head = fib_info_devhash_bucket(dev); 2147 ret = 0; 2148 2149 hlist_for_each_entry(nh, head, nh_hash) { 2150 struct fib_info *fi = nh->nh_parent; 2151 int alive; 2152 2153 BUG_ON(!fi->fib_nhs); 2154 if (nh->fib_nh_dev != dev || fi == prev_fi) 2155 continue; 2156 2157 prev_fi = fi; 2158 alive = 0; 2159 change_nexthops(fi) { 2160 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2161 alive++; 2162 continue; 2163 } 2164 if (!nexthop_nh->fib_nh_dev || 2165 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2166 continue; 2167 if (nexthop_nh->fib_nh_dev != dev || 2168 !__in_dev_get_rtnl(dev)) 2169 continue; 2170 alive++; 2171 nexthop_nh->fib_nh_flags &= ~nh_flags; 2172 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2173 } endfor_nexthops(fi) 2174 2175 if (alive > 0) { 2176 fi->fib_flags &= ~nh_flags; 2177 ret++; 2178 } 2179 2180 fib_rebalance(fi); 2181 } 2182 2183 return ret; 2184 } 2185 2186 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2187 static bool fib_good_nh(const struct fib_nh *nh) 2188 { 2189 int state = NUD_REACHABLE; 2190 2191 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2192 struct neighbour *n; 2193 2194 rcu_read_lock(); 2195 2196 if (likely(nh->fib_nh_gw_family == AF_INET)) 2197 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2198 (__force u32)nh->fib_nh_gw4); 2199 else if (nh->fib_nh_gw_family == AF_INET6) 2200 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2201 &nh->fib_nh_gw6); 2202 else 2203 n = NULL; 2204 if (n) 2205 state = READ_ONCE(n->nud_state); 2206 2207 rcu_read_unlock(); 2208 } 2209 2210 return !!(state & NUD_VALID); 2211 } 2212 2213 void fib_select_multipath(struct fib_result *res, int hash) 2214 { 2215 struct fib_info *fi = res->fi; 2216 struct net *net = fi->fib_net; 2217 bool first = false; 2218 2219 if (unlikely(res->fi->nh)) { 2220 nexthop_path_fib_result(res, hash); 2221 return; 2222 } 2223 2224 change_nexthops(fi) { 2225 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { 2226 if (!fib_good_nh(nexthop_nh)) 2227 continue; 2228 if (!first) { 2229 res->nh_sel = nhsel; 2230 res->nhc = &nexthop_nh->nh_common; 2231 first = true; 2232 } 2233 } 2234 2235 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2236 continue; 2237 2238 res->nh_sel = nhsel; 2239 res->nhc = &nexthop_nh->nh_common; 2240 return; 2241 } endfor_nexthops(fi); 2242 } 2243 #endif 2244 2245 void fib_select_path(struct net *net, struct fib_result *res, 2246 struct flowi4 *fl4, const struct sk_buff *skb) 2247 { 2248 if (fl4->flowi4_oif) 2249 goto check_saddr; 2250 2251 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2252 if (fib_info_num_path(res->fi) > 1) { 2253 int h = fib_multipath_hash(net, fl4, skb, NULL); 2254 2255 fib_select_multipath(res, h); 2256 } 2257 else 2258 #endif 2259 if (!res->prefixlen && 2260 res->table->tb_num_default > 1 && 2261 res->type == RTN_UNICAST) 2262 fib_select_default(fl4, res); 2263 2264 check_saddr: 2265 if (!fl4->saddr) 2266 fl4->saddr = fib_result_prefsrc(net, res); 2267 } 2268