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 /* Paired with READ_ONCE() from fib_table_lookup() */ 282 WRITE_ONCE(fi->fib_dead, 1); 283 fib_info_put(fi); 284 } 285 spin_unlock_bh(&fib_info_lock); 286 } 287 288 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 289 { 290 const struct fib_nh *onh; 291 292 if (fi->nh || ofi->nh) 293 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 294 295 if (ofi->fib_nhs == 0) 296 return 0; 297 298 for_nexthops(fi) { 299 onh = fib_info_nh(ofi, nhsel); 300 301 if (nh->fib_nh_oif != onh->fib_nh_oif || 302 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 303 nh->fib_nh_scope != onh->fib_nh_scope || 304 #ifdef CONFIG_IP_ROUTE_MULTIPATH 305 nh->fib_nh_weight != onh->fib_nh_weight || 306 #endif 307 #ifdef CONFIG_IP_ROUTE_CLASSID 308 nh->nh_tclassid != onh->nh_tclassid || 309 #endif 310 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 311 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 312 return -1; 313 314 if (nh->fib_nh_gw_family == AF_INET && 315 nh->fib_nh_gw4 != onh->fib_nh_gw4) 316 return -1; 317 318 if (nh->fib_nh_gw_family == AF_INET6 && 319 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 320 return -1; 321 } endfor_nexthops(fi); 322 return 0; 323 } 324 325 static inline unsigned int fib_devindex_hashfn(unsigned int val) 326 { 327 return hash_32(val, DEVINDEX_HASHBITS); 328 } 329 330 static struct hlist_head * 331 fib_info_devhash_bucket(const struct net_device *dev) 332 { 333 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex; 334 335 return &fib_info_devhash[fib_devindex_hashfn(val)]; 336 } 337 338 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 339 u32 prefsrc, u32 priority) 340 { 341 unsigned int val = init_val; 342 343 val ^= (protocol << 8) | scope; 344 val ^= prefsrc; 345 val ^= priority; 346 347 return val; 348 } 349 350 static unsigned int fib_info_hashfn_result(unsigned int val) 351 { 352 unsigned int mask = (fib_info_hash_size - 1); 353 354 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 355 } 356 357 static inline unsigned int fib_info_hashfn(struct fib_info *fi) 358 { 359 unsigned int val; 360 361 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 362 fi->fib_scope, (__force u32)fi->fib_prefsrc, 363 fi->fib_priority); 364 365 if (fi->nh) { 366 val ^= fib_devindex_hashfn(fi->nh->id); 367 } else { 368 for_nexthops(fi) { 369 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 370 } endfor_nexthops(fi) 371 } 372 373 return fib_info_hashfn_result(val); 374 } 375 376 /* no metrics, only nexthop id */ 377 static struct fib_info *fib_find_info_nh(struct net *net, 378 const struct fib_config *cfg) 379 { 380 struct hlist_head *head; 381 struct fib_info *fi; 382 unsigned int hash; 383 384 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 385 cfg->fc_protocol, cfg->fc_scope, 386 (__force u32)cfg->fc_prefsrc, 387 cfg->fc_priority); 388 hash = fib_info_hashfn_result(hash); 389 head = &fib_info_hash[hash]; 390 391 hlist_for_each_entry(fi, head, fib_hash) { 392 if (!net_eq(fi->fib_net, net)) 393 continue; 394 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 395 continue; 396 if (cfg->fc_protocol == fi->fib_protocol && 397 cfg->fc_scope == fi->fib_scope && 398 cfg->fc_prefsrc == fi->fib_prefsrc && 399 cfg->fc_priority == fi->fib_priority && 400 cfg->fc_type == fi->fib_type && 401 cfg->fc_table == fi->fib_tb_id && 402 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 403 return fi; 404 } 405 406 return NULL; 407 } 408 409 static struct fib_info *fib_find_info(struct fib_info *nfi) 410 { 411 struct hlist_head *head; 412 struct fib_info *fi; 413 unsigned int hash; 414 415 hash = fib_info_hashfn(nfi); 416 head = &fib_info_hash[hash]; 417 418 hlist_for_each_entry(fi, head, fib_hash) { 419 if (!net_eq(fi->fib_net, nfi->fib_net)) 420 continue; 421 if (fi->fib_nhs != nfi->fib_nhs) 422 continue; 423 if (nfi->fib_protocol == fi->fib_protocol && 424 nfi->fib_scope == fi->fib_scope && 425 nfi->fib_prefsrc == fi->fib_prefsrc && 426 nfi->fib_priority == fi->fib_priority && 427 nfi->fib_type == fi->fib_type && 428 nfi->fib_tb_id == fi->fib_tb_id && 429 memcmp(nfi->fib_metrics, fi->fib_metrics, 430 sizeof(u32) * RTAX_MAX) == 0 && 431 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 432 nh_comp(fi, nfi) == 0) 433 return fi; 434 } 435 436 return NULL; 437 } 438 439 /* Check, that the gateway is already configured. 440 * Used only by redirect accept routine. 441 */ 442 int ip_fib_check_default(__be32 gw, struct net_device *dev) 443 { 444 struct hlist_head *head; 445 struct fib_nh *nh; 446 447 spin_lock(&fib_info_lock); 448 449 head = fib_info_devhash_bucket(dev); 450 451 hlist_for_each_entry(nh, head, nh_hash) { 452 if (nh->fib_nh_dev == dev && 453 nh->fib_nh_gw4 == gw && 454 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 455 spin_unlock(&fib_info_lock); 456 return 0; 457 } 458 } 459 460 spin_unlock(&fib_info_lock); 461 462 return -1; 463 } 464 465 size_t fib_nlmsg_size(struct fib_info *fi) 466 { 467 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 468 + nla_total_size(4) /* RTA_TABLE */ 469 + nla_total_size(4) /* RTA_DST */ 470 + nla_total_size(4) /* RTA_PRIORITY */ 471 + nla_total_size(4) /* RTA_PREFSRC */ 472 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 473 unsigned int nhs = fib_info_num_path(fi); 474 475 /* space for nested metrics */ 476 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 477 478 if (fi->nh) 479 payload += nla_total_size(4); /* RTA_NH_ID */ 480 481 if (nhs) { 482 size_t nh_encapsize = 0; 483 /* Also handles the special case nhs == 1 */ 484 485 /* each nexthop is packed in an attribute */ 486 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 487 unsigned int i; 488 489 /* may contain flow and gateway attribute */ 490 nhsize += 2 * nla_total_size(4); 491 492 /* grab encap info */ 493 for (i = 0; i < fib_info_num_path(fi); i++) { 494 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 495 496 if (nhc->nhc_lwtstate) { 497 /* RTA_ENCAP_TYPE */ 498 nh_encapsize += lwtunnel_get_encap_size( 499 nhc->nhc_lwtstate); 500 /* RTA_ENCAP */ 501 nh_encapsize += nla_total_size(2); 502 } 503 } 504 505 /* all nexthops are packed in a nested attribute */ 506 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 507 508 } 509 510 return payload; 511 } 512 513 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 514 int dst_len, u32 tb_id, const struct nl_info *info, 515 unsigned int nlm_flags) 516 { 517 struct fib_rt_info fri; 518 struct sk_buff *skb; 519 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 520 int err = -ENOBUFS; 521 522 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 523 if (!skb) 524 goto errout; 525 526 fri.fi = fa->fa_info; 527 fri.tb_id = tb_id; 528 fri.dst = key; 529 fri.dst_len = dst_len; 530 fri.dscp = fa->fa_dscp; 531 fri.type = fa->fa_type; 532 fri.offload = READ_ONCE(fa->offload); 533 fri.trap = READ_ONCE(fa->trap); 534 fri.offload_failed = READ_ONCE(fa->offload_failed); 535 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 536 if (err < 0) { 537 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 538 WARN_ON(err == -EMSGSIZE); 539 kfree_skb(skb); 540 goto errout; 541 } 542 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 543 info->nlh, GFP_KERNEL); 544 return; 545 errout: 546 if (err < 0) 547 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 548 } 549 550 static int fib_detect_death(struct fib_info *fi, int order, 551 struct fib_info **last_resort, int *last_idx, 552 int dflt) 553 { 554 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 555 struct neighbour *n; 556 int state = NUD_NONE; 557 558 if (likely(nhc->nhc_gw_family == AF_INET)) 559 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 560 else if (nhc->nhc_gw_family == AF_INET6) 561 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 562 nhc->nhc_dev); 563 else 564 n = NULL; 565 566 if (n) { 567 state = READ_ONCE(n->nud_state); 568 neigh_release(n); 569 } else { 570 return 0; 571 } 572 if (state == NUD_REACHABLE) 573 return 0; 574 if ((state & NUD_VALID) && order != dflt) 575 return 0; 576 if ((state & NUD_VALID) || 577 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 578 *last_resort = fi; 579 *last_idx = order; 580 } 581 return 1; 582 } 583 584 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 585 struct nlattr *encap, u16 encap_type, 586 void *cfg, gfp_t gfp_flags, 587 struct netlink_ext_ack *extack) 588 { 589 int err; 590 591 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 592 gfp_flags); 593 if (!nhc->nhc_pcpu_rth_output) 594 return -ENOMEM; 595 596 if (encap) { 597 struct lwtunnel_state *lwtstate; 598 599 if (encap_type == LWTUNNEL_ENCAP_NONE) { 600 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 601 err = -EINVAL; 602 goto lwt_failure; 603 } 604 err = lwtunnel_build_state(net, encap_type, encap, 605 nhc->nhc_family, cfg, &lwtstate, 606 extack); 607 if (err) 608 goto lwt_failure; 609 610 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 611 } 612 613 return 0; 614 615 lwt_failure: 616 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 617 nhc->nhc_pcpu_rth_output = NULL; 618 return err; 619 } 620 EXPORT_SYMBOL_GPL(fib_nh_common_init); 621 622 int fib_nh_init(struct net *net, struct fib_nh *nh, 623 struct fib_config *cfg, int nh_weight, 624 struct netlink_ext_ack *extack) 625 { 626 int err; 627 628 nh->fib_nh_family = AF_INET; 629 630 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 631 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 632 if (err) 633 return err; 634 635 nh->fib_nh_oif = cfg->fc_oif; 636 nh->fib_nh_gw_family = cfg->fc_gw_family; 637 if (cfg->fc_gw_family == AF_INET) 638 nh->fib_nh_gw4 = cfg->fc_gw4; 639 else if (cfg->fc_gw_family == AF_INET6) 640 nh->fib_nh_gw6 = cfg->fc_gw6; 641 642 nh->fib_nh_flags = cfg->fc_flags; 643 644 #ifdef CONFIG_IP_ROUTE_CLASSID 645 nh->nh_tclassid = cfg->fc_flow; 646 if (nh->nh_tclassid) 647 atomic_inc(&net->ipv4.fib_num_tclassid_users); 648 #endif 649 #ifdef CONFIG_IP_ROUTE_MULTIPATH 650 nh->fib_nh_weight = nh_weight; 651 #endif 652 return 0; 653 } 654 655 #ifdef CONFIG_IP_ROUTE_MULTIPATH 656 657 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 658 struct netlink_ext_ack *extack) 659 { 660 int nhs = 0; 661 662 while (rtnh_ok(rtnh, remaining)) { 663 nhs++; 664 rtnh = rtnh_next(rtnh, &remaining); 665 } 666 667 /* leftover implies invalid nexthop configuration, discard it */ 668 if (remaining > 0) { 669 NL_SET_ERR_MSG(extack, 670 "Invalid nexthop configuration - extra data after nexthops"); 671 nhs = 0; 672 } 673 674 return nhs; 675 } 676 677 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 678 struct netlink_ext_ack *extack) 679 { 680 if (nla_len(nla) < sizeof(*gw)) { 681 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 682 return -EINVAL; 683 } 684 685 *gw = nla_get_in_addr(nla); 686 687 return 0; 688 } 689 690 /* only called when fib_nh is integrated into fib_info */ 691 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 692 int remaining, struct fib_config *cfg, 693 struct netlink_ext_ack *extack) 694 { 695 struct net *net = fi->fib_net; 696 struct fib_config fib_cfg; 697 struct fib_nh *nh; 698 int ret; 699 700 change_nexthops(fi) { 701 int attrlen; 702 703 memset(&fib_cfg, 0, sizeof(fib_cfg)); 704 705 if (!rtnh_ok(rtnh, remaining)) { 706 NL_SET_ERR_MSG(extack, 707 "Invalid nexthop configuration - extra data after nexthop"); 708 return -EINVAL; 709 } 710 711 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 712 NL_SET_ERR_MSG(extack, 713 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 714 return -EINVAL; 715 } 716 717 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 718 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 719 720 attrlen = rtnh_attrlen(rtnh); 721 if (attrlen > 0) { 722 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 723 724 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 725 nlav = nla_find(attrs, attrlen, RTA_VIA); 726 if (nla && nlav) { 727 NL_SET_ERR_MSG(extack, 728 "Nexthop configuration can not contain both GATEWAY and VIA"); 729 return -EINVAL; 730 } 731 if (nla) { 732 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 733 extack); 734 if (ret) 735 goto errout; 736 737 if (fib_cfg.fc_gw4) 738 fib_cfg.fc_gw_family = AF_INET; 739 } else if (nlav) { 740 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 741 if (ret) 742 goto errout; 743 } 744 745 nla = nla_find(attrs, attrlen, RTA_FLOW); 746 if (nla) { 747 if (nla_len(nla) < sizeof(u32)) { 748 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 749 return -EINVAL; 750 } 751 fib_cfg.fc_flow = nla_get_u32(nla); 752 } 753 754 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 755 /* RTA_ENCAP_TYPE length checked in 756 * lwtunnel_valid_encap_type_attr 757 */ 758 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 759 if (nla) 760 fib_cfg.fc_encap_type = nla_get_u16(nla); 761 } 762 763 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 764 rtnh->rtnh_hops + 1, extack); 765 if (ret) 766 goto errout; 767 768 rtnh = rtnh_next(rtnh, &remaining); 769 } endfor_nexthops(fi); 770 771 ret = -EINVAL; 772 nh = fib_info_nh(fi, 0); 773 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 774 NL_SET_ERR_MSG(extack, 775 "Nexthop device index does not match RTA_OIF"); 776 goto errout; 777 } 778 if (cfg->fc_gw_family) { 779 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 780 (cfg->fc_gw_family == AF_INET && 781 nh->fib_nh_gw4 != cfg->fc_gw4) || 782 (cfg->fc_gw_family == AF_INET6 && 783 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 784 NL_SET_ERR_MSG(extack, 785 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 786 goto errout; 787 } 788 } 789 #ifdef CONFIG_IP_ROUTE_CLASSID 790 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 791 NL_SET_ERR_MSG(extack, 792 "Nexthop class id does not match RTA_FLOW"); 793 goto errout; 794 } 795 #endif 796 ret = 0; 797 errout: 798 return ret; 799 } 800 801 /* only called when fib_nh is integrated into fib_info */ 802 static void fib_rebalance(struct fib_info *fi) 803 { 804 int total; 805 int w; 806 807 if (fib_info_num_path(fi) < 2) 808 return; 809 810 total = 0; 811 for_nexthops(fi) { 812 if (nh->fib_nh_flags & RTNH_F_DEAD) 813 continue; 814 815 if (ip_ignore_linkdown(nh->fib_nh_dev) && 816 nh->fib_nh_flags & RTNH_F_LINKDOWN) 817 continue; 818 819 total += nh->fib_nh_weight; 820 } endfor_nexthops(fi); 821 822 w = 0; 823 change_nexthops(fi) { 824 int upper_bound; 825 826 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 827 upper_bound = -1; 828 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 829 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 830 upper_bound = -1; 831 } else { 832 w += nexthop_nh->fib_nh_weight; 833 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 834 total) - 1; 835 } 836 837 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 838 } endfor_nexthops(fi); 839 } 840 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 841 842 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 843 int remaining, struct fib_config *cfg, 844 struct netlink_ext_ack *extack) 845 { 846 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 847 848 return -EINVAL; 849 } 850 851 #define fib_rebalance(fi) do { } while (0) 852 853 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 854 855 static int fib_encap_match(struct net *net, u16 encap_type, 856 struct nlattr *encap, 857 const struct fib_nh *nh, 858 const struct fib_config *cfg, 859 struct netlink_ext_ack *extack) 860 { 861 struct lwtunnel_state *lwtstate; 862 int ret, result = 0; 863 864 if (encap_type == LWTUNNEL_ENCAP_NONE) 865 return 0; 866 867 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 868 cfg, &lwtstate, extack); 869 if (!ret) { 870 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 871 lwtstate_free(lwtstate); 872 } 873 874 return result; 875 } 876 877 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 878 struct netlink_ext_ack *extack) 879 { 880 #ifdef CONFIG_IP_ROUTE_MULTIPATH 881 struct rtnexthop *rtnh; 882 int remaining; 883 #endif 884 885 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 886 return 1; 887 888 if (cfg->fc_nh_id) { 889 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 890 return 0; 891 return 1; 892 } 893 894 if (fi->nh) { 895 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 896 return 1; 897 return 0; 898 } 899 900 if (cfg->fc_oif || cfg->fc_gw_family) { 901 struct fib_nh *nh; 902 903 nh = fib_info_nh(fi, 0); 904 if (cfg->fc_encap) { 905 if (fib_encap_match(net, cfg->fc_encap_type, 906 cfg->fc_encap, nh, cfg, extack)) 907 return 1; 908 } 909 #ifdef CONFIG_IP_ROUTE_CLASSID 910 if (cfg->fc_flow && 911 cfg->fc_flow != nh->nh_tclassid) 912 return 1; 913 #endif 914 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 915 (cfg->fc_gw_family && 916 cfg->fc_gw_family != nh->fib_nh_gw_family)) 917 return 1; 918 919 if (cfg->fc_gw_family == AF_INET && 920 cfg->fc_gw4 != nh->fib_nh_gw4) 921 return 1; 922 923 if (cfg->fc_gw_family == AF_INET6 && 924 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 925 return 1; 926 927 return 0; 928 } 929 930 #ifdef CONFIG_IP_ROUTE_MULTIPATH 931 if (!cfg->fc_mp) 932 return 0; 933 934 rtnh = cfg->fc_mp; 935 remaining = cfg->fc_mp_len; 936 937 for_nexthops(fi) { 938 int attrlen; 939 940 if (!rtnh_ok(rtnh, remaining)) 941 return -EINVAL; 942 943 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 944 return 1; 945 946 attrlen = rtnh_attrlen(rtnh); 947 if (attrlen > 0) { 948 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 949 int err; 950 951 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 952 nlav = nla_find(attrs, attrlen, RTA_VIA); 953 if (nla && nlav) { 954 NL_SET_ERR_MSG(extack, 955 "Nexthop configuration can not contain both GATEWAY and VIA"); 956 return -EINVAL; 957 } 958 959 if (nla) { 960 __be32 gw; 961 962 err = fib_gw_from_attr(&gw, nla, extack); 963 if (err) 964 return err; 965 966 if (nh->fib_nh_gw_family != AF_INET || 967 gw != nh->fib_nh_gw4) 968 return 1; 969 } else if (nlav) { 970 struct fib_config cfg2; 971 972 err = fib_gw_from_via(&cfg2, nlav, extack); 973 if (err) 974 return err; 975 976 switch (nh->fib_nh_gw_family) { 977 case AF_INET: 978 if (cfg2.fc_gw_family != AF_INET || 979 cfg2.fc_gw4 != nh->fib_nh_gw4) 980 return 1; 981 break; 982 case AF_INET6: 983 if (cfg2.fc_gw_family != AF_INET6 || 984 ipv6_addr_cmp(&cfg2.fc_gw6, 985 &nh->fib_nh_gw6)) 986 return 1; 987 break; 988 } 989 } 990 991 #ifdef CONFIG_IP_ROUTE_CLASSID 992 nla = nla_find(attrs, attrlen, RTA_FLOW); 993 if (nla) { 994 if (nla_len(nla) < sizeof(u32)) { 995 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 996 return -EINVAL; 997 } 998 if (nla_get_u32(nla) != nh->nh_tclassid) 999 return 1; 1000 } 1001 #endif 1002 } 1003 1004 rtnh = rtnh_next(rtnh, &remaining); 1005 } endfor_nexthops(fi); 1006 #endif 1007 return 0; 1008 } 1009 1010 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1011 { 1012 struct nlattr *nla; 1013 int remaining; 1014 1015 if (!cfg->fc_mx) 1016 return true; 1017 1018 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1019 int type = nla_type(nla); 1020 u32 fi_val, val; 1021 1022 if (!type) 1023 continue; 1024 if (type > RTAX_MAX) 1025 return false; 1026 1027 type = array_index_nospec(type, RTAX_MAX + 1); 1028 if (type == RTAX_CC_ALGO) { 1029 char tmp[TCP_CA_NAME_MAX]; 1030 bool ecn_ca = false; 1031 1032 nla_strscpy(tmp, nla, sizeof(tmp)); 1033 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1034 } else { 1035 if (nla_len(nla) != sizeof(u32)) 1036 return false; 1037 val = nla_get_u32(nla); 1038 } 1039 1040 fi_val = fi->fib_metrics->metrics[type - 1]; 1041 if (type == RTAX_FEATURES) 1042 fi_val &= ~DST_FEATURE_ECN_CA; 1043 1044 if (fi_val != val) 1045 return false; 1046 } 1047 1048 return true; 1049 } 1050 1051 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1052 u32 table, struct netlink_ext_ack *extack) 1053 { 1054 struct fib6_config cfg = { 1055 .fc_table = table, 1056 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1057 .fc_ifindex = nh->fib_nh_oif, 1058 .fc_gateway = nh->fib_nh_gw6, 1059 }; 1060 struct fib6_nh fib6_nh = {}; 1061 int err; 1062 1063 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1064 if (!err) { 1065 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1066 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1067 GFP_KERNEL); 1068 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1069 nh->fib_nh_scope = RT_SCOPE_LINK; 1070 1071 ipv6_stub->fib6_nh_release(&fib6_nh); 1072 } 1073 1074 return err; 1075 } 1076 1077 /* 1078 * Picture 1079 * ------- 1080 * 1081 * Semantics of nexthop is very messy by historical reasons. 1082 * We have to take into account, that: 1083 * a) gateway can be actually local interface address, 1084 * so that gatewayed route is direct. 1085 * b) gateway must be on-link address, possibly 1086 * described not by an ifaddr, but also by a direct route. 1087 * c) If both gateway and interface are specified, they should not 1088 * contradict. 1089 * d) If we use tunnel routes, gateway could be not on-link. 1090 * 1091 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1092 * results in pretty ugly and hairy code with obscure logic. 1093 * 1094 * I chose to generalized it instead, so that the size 1095 * of code does not increase practically, but it becomes 1096 * much more general. 1097 * Every prefix is assigned a "scope" value: "host" is local address, 1098 * "link" is direct route, 1099 * [ ... "site" ... "interior" ... ] 1100 * and "universe" is true gateway route with global meaning. 1101 * 1102 * Every prefix refers to a set of "nexthop"s (gw, oif), 1103 * where gw must have narrower scope. This recursion stops 1104 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1105 * which means that gw is forced to be on link. 1106 * 1107 * Code is still hairy, but now it is apparently logically 1108 * consistent and very flexible. F.e. as by-product it allows 1109 * to co-exists in peace independent exterior and interior 1110 * routing processes. 1111 * 1112 * Normally it looks as following. 1113 * 1114 * {universe prefix} -> (gw, oif) [scope link] 1115 * | 1116 * |-> {link prefix} -> (gw, oif) [scope local] 1117 * | 1118 * |-> {local prefix} (terminal node) 1119 */ 1120 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1121 u8 scope, struct netlink_ext_ack *extack) 1122 { 1123 struct net_device *dev; 1124 struct fib_result res; 1125 int err = 0; 1126 1127 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1128 unsigned int addr_type; 1129 1130 if (scope >= RT_SCOPE_LINK) { 1131 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1132 return -EINVAL; 1133 } 1134 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1135 if (!dev) { 1136 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1137 return -ENODEV; 1138 } 1139 if (!(dev->flags & IFF_UP)) { 1140 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1141 return -ENETDOWN; 1142 } 1143 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1144 if (addr_type != RTN_UNICAST) { 1145 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1146 return -EINVAL; 1147 } 1148 if (!netif_carrier_ok(dev)) 1149 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1150 nh->fib_nh_dev = dev; 1151 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1152 nh->fib_nh_scope = RT_SCOPE_LINK; 1153 return 0; 1154 } 1155 rcu_read_lock(); 1156 { 1157 struct fib_table *tbl = NULL; 1158 struct flowi4 fl4 = { 1159 .daddr = nh->fib_nh_gw4, 1160 .flowi4_scope = scope + 1, 1161 .flowi4_oif = nh->fib_nh_oif, 1162 .flowi4_iif = LOOPBACK_IFINDEX, 1163 }; 1164 1165 /* It is not necessary, but requires a bit of thinking */ 1166 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1167 fl4.flowi4_scope = RT_SCOPE_LINK; 1168 1169 if (table && table != RT_TABLE_MAIN) 1170 tbl = fib_get_table(net, table); 1171 1172 if (tbl) 1173 err = fib_table_lookup(tbl, &fl4, &res, 1174 FIB_LOOKUP_IGNORE_LINKSTATE | 1175 FIB_LOOKUP_NOREF); 1176 1177 /* on error or if no table given do full lookup. This 1178 * is needed for example when nexthops are in the local 1179 * table rather than the given table 1180 */ 1181 if (!tbl || err) { 1182 err = fib_lookup(net, &fl4, &res, 1183 FIB_LOOKUP_IGNORE_LINKSTATE); 1184 } 1185 1186 if (err) { 1187 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1188 goto out; 1189 } 1190 } 1191 1192 err = -EINVAL; 1193 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1194 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1195 goto out; 1196 } 1197 nh->fib_nh_scope = res.scope; 1198 nh->fib_nh_oif = FIB_RES_OIF(res); 1199 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1200 if (!dev) { 1201 NL_SET_ERR_MSG(extack, 1202 "No egress device for nexthop gateway"); 1203 goto out; 1204 } 1205 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1206 if (!netif_carrier_ok(dev)) 1207 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1208 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1209 out: 1210 rcu_read_unlock(); 1211 return err; 1212 } 1213 1214 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1215 struct netlink_ext_ack *extack) 1216 { 1217 struct in_device *in_dev; 1218 int err; 1219 1220 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1221 NL_SET_ERR_MSG(extack, 1222 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1223 return -EINVAL; 1224 } 1225 1226 rcu_read_lock(); 1227 1228 err = -ENODEV; 1229 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1230 if (!in_dev) 1231 goto out; 1232 err = -ENETDOWN; 1233 if (!(in_dev->dev->flags & IFF_UP)) { 1234 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1235 goto out; 1236 } 1237 1238 nh->fib_nh_dev = in_dev->dev; 1239 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1240 nh->fib_nh_scope = RT_SCOPE_HOST; 1241 if (!netif_carrier_ok(nh->fib_nh_dev)) 1242 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1243 err = 0; 1244 out: 1245 rcu_read_unlock(); 1246 return err; 1247 } 1248 1249 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1250 struct netlink_ext_ack *extack) 1251 { 1252 int err; 1253 1254 if (nh->fib_nh_gw_family == AF_INET) 1255 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1256 else if (nh->fib_nh_gw_family == AF_INET6) 1257 err = fib_check_nh_v6_gw(net, nh, table, extack); 1258 else 1259 err = fib_check_nh_nongw(net, nh, extack); 1260 1261 return err; 1262 } 1263 1264 static struct hlist_head * 1265 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1266 { 1267 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1268 fib_info_hash_bits); 1269 1270 return &fib_info_laddrhash[slot]; 1271 } 1272 1273 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1274 struct hlist_head *new_laddrhash, 1275 unsigned int new_size) 1276 { 1277 struct hlist_head *old_info_hash, *old_laddrhash; 1278 unsigned int old_size = fib_info_hash_size; 1279 unsigned int i; 1280 1281 spin_lock_bh(&fib_info_lock); 1282 old_info_hash = fib_info_hash; 1283 old_laddrhash = fib_info_laddrhash; 1284 fib_info_hash_size = new_size; 1285 fib_info_hash_bits = ilog2(new_size); 1286 1287 for (i = 0; i < old_size; i++) { 1288 struct hlist_head *head = &fib_info_hash[i]; 1289 struct hlist_node *n; 1290 struct fib_info *fi; 1291 1292 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1293 struct hlist_head *dest; 1294 unsigned int new_hash; 1295 1296 new_hash = fib_info_hashfn(fi); 1297 dest = &new_info_hash[new_hash]; 1298 hlist_add_head(&fi->fib_hash, dest); 1299 } 1300 } 1301 fib_info_hash = new_info_hash; 1302 1303 fib_info_laddrhash = new_laddrhash; 1304 for (i = 0; i < old_size; i++) { 1305 struct hlist_head *lhead = &old_laddrhash[i]; 1306 struct hlist_node *n; 1307 struct fib_info *fi; 1308 1309 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1310 struct hlist_head *ldest; 1311 1312 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1313 fi->fib_prefsrc); 1314 hlist_add_head(&fi->fib_lhash, ldest); 1315 } 1316 } 1317 1318 spin_unlock_bh(&fib_info_lock); 1319 1320 kvfree(old_info_hash); 1321 kvfree(old_laddrhash); 1322 } 1323 1324 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1325 unsigned char scope) 1326 { 1327 struct fib_nh *nh; 1328 __be32 saddr; 1329 1330 if (nhc->nhc_family != AF_INET) 1331 return inet_select_addr(nhc->nhc_dev, 0, scope); 1332 1333 nh = container_of(nhc, struct fib_nh, nh_common); 1334 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1335 1336 WRITE_ONCE(nh->nh_saddr, saddr); 1337 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); 1338 1339 return saddr; 1340 } 1341 1342 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1343 { 1344 struct fib_nh_common *nhc = res->nhc; 1345 1346 if (res->fi->fib_prefsrc) 1347 return res->fi->fib_prefsrc; 1348 1349 if (nhc->nhc_family == AF_INET) { 1350 struct fib_nh *nh; 1351 1352 nh = container_of(nhc, struct fib_nh, nh_common); 1353 if (READ_ONCE(nh->nh_saddr_genid) == 1354 atomic_read(&net->ipv4.dev_addr_genid)) 1355 return READ_ONCE(nh->nh_saddr); 1356 } 1357 1358 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1359 } 1360 1361 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1362 { 1363 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1364 fib_prefsrc != cfg->fc_dst) { 1365 u32 tb_id = cfg->fc_table; 1366 int rc; 1367 1368 if (tb_id == RT_TABLE_MAIN) 1369 tb_id = RT_TABLE_LOCAL; 1370 1371 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1372 fib_prefsrc, tb_id); 1373 1374 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1375 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1376 fib_prefsrc, RT_TABLE_LOCAL); 1377 } 1378 1379 if (rc != RTN_LOCAL) 1380 return false; 1381 } 1382 return true; 1383 } 1384 1385 struct fib_info *fib_create_info(struct fib_config *cfg, 1386 struct netlink_ext_ack *extack) 1387 { 1388 int err; 1389 struct fib_info *fi = NULL; 1390 struct nexthop *nh = NULL; 1391 struct fib_info *ofi; 1392 int nhs = 1; 1393 struct net *net = cfg->fc_nlinfo.nl_net; 1394 1395 if (cfg->fc_type > RTN_MAX) 1396 goto err_inval; 1397 1398 /* Fast check to catch the most weird cases */ 1399 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1400 NL_SET_ERR_MSG(extack, "Invalid scope"); 1401 goto err_inval; 1402 } 1403 1404 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1405 NL_SET_ERR_MSG(extack, 1406 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1407 goto err_inval; 1408 } 1409 1410 if (cfg->fc_nh_id) { 1411 if (!cfg->fc_mx) { 1412 fi = fib_find_info_nh(net, cfg); 1413 if (fi) { 1414 refcount_inc(&fi->fib_treeref); 1415 return fi; 1416 } 1417 } 1418 1419 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1420 if (!nh) { 1421 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1422 goto err_inval; 1423 } 1424 nhs = 0; 1425 } 1426 1427 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1428 if (cfg->fc_mp) { 1429 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1430 if (nhs == 0) 1431 goto err_inval; 1432 } 1433 #endif 1434 1435 err = -ENOBUFS; 1436 1437 /* Paired with WRITE_ONCE() in fib_release_info() */ 1438 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1439 unsigned int new_size = fib_info_hash_size << 1; 1440 struct hlist_head *new_info_hash; 1441 struct hlist_head *new_laddrhash; 1442 size_t bytes; 1443 1444 if (!new_size) 1445 new_size = 16; 1446 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1447 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1448 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1449 if (!new_info_hash || !new_laddrhash) { 1450 kvfree(new_info_hash); 1451 kvfree(new_laddrhash); 1452 } else { 1453 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1454 } 1455 if (!fib_info_hash_size) 1456 goto failure; 1457 } 1458 1459 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1460 if (!fi) 1461 goto failure; 1462 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1463 cfg->fc_mx_len, extack); 1464 if (IS_ERR(fi->fib_metrics)) { 1465 err = PTR_ERR(fi->fib_metrics); 1466 kfree(fi); 1467 return ERR_PTR(err); 1468 } 1469 1470 fi->fib_net = net; 1471 fi->fib_protocol = cfg->fc_protocol; 1472 fi->fib_scope = cfg->fc_scope; 1473 fi->fib_flags = cfg->fc_flags; 1474 fi->fib_priority = cfg->fc_priority; 1475 fi->fib_prefsrc = cfg->fc_prefsrc; 1476 fi->fib_type = cfg->fc_type; 1477 fi->fib_tb_id = cfg->fc_table; 1478 1479 fi->fib_nhs = nhs; 1480 if (nh) { 1481 if (!nexthop_get(nh)) { 1482 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1483 err = -EINVAL; 1484 } else { 1485 err = 0; 1486 fi->nh = nh; 1487 } 1488 } else { 1489 change_nexthops(fi) { 1490 nexthop_nh->nh_parent = fi; 1491 } endfor_nexthops(fi) 1492 1493 if (cfg->fc_mp) 1494 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1495 extack); 1496 else 1497 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1498 } 1499 1500 if (err != 0) 1501 goto failure; 1502 1503 if (fib_props[cfg->fc_type].error) { 1504 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1505 NL_SET_ERR_MSG(extack, 1506 "Gateway, device and multipath can not be specified for this route type"); 1507 goto err_inval; 1508 } 1509 goto link_it; 1510 } else { 1511 switch (cfg->fc_type) { 1512 case RTN_UNICAST: 1513 case RTN_LOCAL: 1514 case RTN_BROADCAST: 1515 case RTN_ANYCAST: 1516 case RTN_MULTICAST: 1517 break; 1518 default: 1519 NL_SET_ERR_MSG(extack, "Invalid route type"); 1520 goto err_inval; 1521 } 1522 } 1523 1524 if (cfg->fc_scope > RT_SCOPE_HOST) { 1525 NL_SET_ERR_MSG(extack, "Invalid scope"); 1526 goto err_inval; 1527 } 1528 1529 if (fi->nh) { 1530 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1531 if (err) 1532 goto failure; 1533 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1534 struct fib_nh *nh = fi->fib_nh; 1535 1536 /* Local address is added. */ 1537 if (nhs != 1) { 1538 NL_SET_ERR_MSG(extack, 1539 "Route with host scope can not have multiple nexthops"); 1540 goto err_inval; 1541 } 1542 if (nh->fib_nh_gw_family) { 1543 NL_SET_ERR_MSG(extack, 1544 "Route with host scope can not have a gateway"); 1545 goto err_inval; 1546 } 1547 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1548 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1549 err = -ENODEV; 1550 if (!nh->fib_nh_dev) 1551 goto failure; 1552 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1553 GFP_KERNEL); 1554 } else { 1555 int linkdown = 0; 1556 1557 change_nexthops(fi) { 1558 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1559 cfg->fc_table, cfg->fc_scope, 1560 extack); 1561 if (err != 0) 1562 goto failure; 1563 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1564 linkdown++; 1565 } endfor_nexthops(fi) 1566 if (linkdown == fi->fib_nhs) 1567 fi->fib_flags |= RTNH_F_LINKDOWN; 1568 } 1569 1570 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1571 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1572 goto err_inval; 1573 } 1574 1575 if (!fi->nh) { 1576 change_nexthops(fi) { 1577 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1578 fi->fib_scope); 1579 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1580 fi->fib_nh_is_v6 = true; 1581 } endfor_nexthops(fi) 1582 1583 fib_rebalance(fi); 1584 } 1585 1586 link_it: 1587 ofi = fib_find_info(fi); 1588 if (ofi) { 1589 /* fib_table_lookup() should not see @fi yet. */ 1590 fi->fib_dead = 1; 1591 free_fib_info(fi); 1592 refcount_inc(&ofi->fib_treeref); 1593 return ofi; 1594 } 1595 1596 refcount_set(&fi->fib_treeref, 1); 1597 refcount_set(&fi->fib_clntref, 1); 1598 spin_lock_bh(&fib_info_lock); 1599 fib_info_cnt++; 1600 hlist_add_head(&fi->fib_hash, 1601 &fib_info_hash[fib_info_hashfn(fi)]); 1602 if (fi->fib_prefsrc) { 1603 struct hlist_head *head; 1604 1605 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1606 hlist_add_head(&fi->fib_lhash, head); 1607 } 1608 if (fi->nh) { 1609 list_add(&fi->nh_list, &nh->fi_list); 1610 } else { 1611 change_nexthops(fi) { 1612 struct hlist_head *head; 1613 1614 if (!nexthop_nh->fib_nh_dev) 1615 continue; 1616 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1617 hlist_add_head(&nexthop_nh->nh_hash, head); 1618 } endfor_nexthops(fi) 1619 } 1620 spin_unlock_bh(&fib_info_lock); 1621 return fi; 1622 1623 err_inval: 1624 err = -EINVAL; 1625 1626 failure: 1627 if (fi) { 1628 /* fib_table_lookup() should not see @fi yet. */ 1629 fi->fib_dead = 1; 1630 free_fib_info(fi); 1631 } 1632 1633 return ERR_PTR(err); 1634 } 1635 1636 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1637 u8 rt_family, unsigned char *flags, bool skip_oif) 1638 { 1639 if (nhc->nhc_flags & RTNH_F_DEAD) 1640 *flags |= RTNH_F_DEAD; 1641 1642 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1643 *flags |= RTNH_F_LINKDOWN; 1644 1645 rcu_read_lock(); 1646 switch (nhc->nhc_family) { 1647 case AF_INET: 1648 if (ip_ignore_linkdown(nhc->nhc_dev)) 1649 *flags |= RTNH_F_DEAD; 1650 break; 1651 case AF_INET6: 1652 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1653 *flags |= RTNH_F_DEAD; 1654 break; 1655 } 1656 rcu_read_unlock(); 1657 } 1658 1659 switch (nhc->nhc_gw_family) { 1660 case AF_INET: 1661 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1662 goto nla_put_failure; 1663 break; 1664 case AF_INET6: 1665 /* if gateway family does not match nexthop family 1666 * gateway is encoded as RTA_VIA 1667 */ 1668 if (rt_family != nhc->nhc_gw_family) { 1669 int alen = sizeof(struct in6_addr); 1670 struct nlattr *nla; 1671 struct rtvia *via; 1672 1673 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1674 if (!nla) 1675 goto nla_put_failure; 1676 1677 via = nla_data(nla); 1678 via->rtvia_family = AF_INET6; 1679 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1680 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1681 &nhc->nhc_gw.ipv6) < 0) { 1682 goto nla_put_failure; 1683 } 1684 break; 1685 } 1686 1687 *flags |= (nhc->nhc_flags & 1688 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1689 1690 if (!skip_oif && nhc->nhc_dev && 1691 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1692 goto nla_put_failure; 1693 1694 if (nhc->nhc_lwtstate && 1695 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1696 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1697 goto nla_put_failure; 1698 1699 return 0; 1700 1701 nla_put_failure: 1702 return -EMSGSIZE; 1703 } 1704 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1705 1706 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1707 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1708 int nh_weight, u8 rt_family, u32 nh_tclassid) 1709 { 1710 const struct net_device *dev = nhc->nhc_dev; 1711 struct rtnexthop *rtnh; 1712 unsigned char flags = 0; 1713 1714 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1715 if (!rtnh) 1716 goto nla_put_failure; 1717 1718 rtnh->rtnh_hops = nh_weight - 1; 1719 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1720 1721 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1722 goto nla_put_failure; 1723 1724 rtnh->rtnh_flags = flags; 1725 1726 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1727 goto nla_put_failure; 1728 1729 /* length of rtnetlink header + attributes */ 1730 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1731 1732 return 0; 1733 1734 nla_put_failure: 1735 return -EMSGSIZE; 1736 } 1737 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1738 #endif 1739 1740 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1741 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1742 { 1743 struct nlattr *mp; 1744 1745 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1746 if (!mp) 1747 goto nla_put_failure; 1748 1749 if (unlikely(fi->nh)) { 1750 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1751 goto nla_put_failure; 1752 goto mp_end; 1753 } 1754 1755 for_nexthops(fi) { 1756 u32 nh_tclassid = 0; 1757 #ifdef CONFIG_IP_ROUTE_CLASSID 1758 nh_tclassid = nh->nh_tclassid; 1759 #endif 1760 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1761 AF_INET, nh_tclassid) < 0) 1762 goto nla_put_failure; 1763 } endfor_nexthops(fi); 1764 1765 mp_end: 1766 nla_nest_end(skb, mp); 1767 1768 return 0; 1769 1770 nla_put_failure: 1771 return -EMSGSIZE; 1772 } 1773 #else 1774 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1775 { 1776 return 0; 1777 } 1778 #endif 1779 1780 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1781 const struct fib_rt_info *fri, unsigned int flags) 1782 { 1783 unsigned int nhs = fib_info_num_path(fri->fi); 1784 struct fib_info *fi = fri->fi; 1785 u32 tb_id = fri->tb_id; 1786 struct nlmsghdr *nlh; 1787 struct rtmsg *rtm; 1788 1789 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1790 if (!nlh) 1791 return -EMSGSIZE; 1792 1793 rtm = nlmsg_data(nlh); 1794 rtm->rtm_family = AF_INET; 1795 rtm->rtm_dst_len = fri->dst_len; 1796 rtm->rtm_src_len = 0; 1797 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); 1798 if (tb_id < 256) 1799 rtm->rtm_table = tb_id; 1800 else 1801 rtm->rtm_table = RT_TABLE_COMPAT; 1802 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1803 goto nla_put_failure; 1804 rtm->rtm_type = fri->type; 1805 rtm->rtm_flags = fi->fib_flags; 1806 rtm->rtm_scope = fi->fib_scope; 1807 rtm->rtm_protocol = fi->fib_protocol; 1808 1809 if (rtm->rtm_dst_len && 1810 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1811 goto nla_put_failure; 1812 if (fi->fib_priority && 1813 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1814 goto nla_put_failure; 1815 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1816 goto nla_put_failure; 1817 1818 if (fi->fib_prefsrc && 1819 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1820 goto nla_put_failure; 1821 1822 if (fi->nh) { 1823 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1824 goto nla_put_failure; 1825 if (nexthop_is_blackhole(fi->nh)) 1826 rtm->rtm_type = RTN_BLACKHOLE; 1827 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1828 goto offload; 1829 } 1830 1831 if (nhs == 1) { 1832 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1833 unsigned char flags = 0; 1834 1835 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1836 goto nla_put_failure; 1837 1838 rtm->rtm_flags = flags; 1839 #ifdef CONFIG_IP_ROUTE_CLASSID 1840 if (nhc->nhc_family == AF_INET) { 1841 struct fib_nh *nh; 1842 1843 nh = container_of(nhc, struct fib_nh, nh_common); 1844 if (nh->nh_tclassid && 1845 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1846 goto nla_put_failure; 1847 } 1848 #endif 1849 } else { 1850 if (fib_add_multipath(skb, fi) < 0) 1851 goto nla_put_failure; 1852 } 1853 1854 offload: 1855 if (fri->offload) 1856 rtm->rtm_flags |= RTM_F_OFFLOAD; 1857 if (fri->trap) 1858 rtm->rtm_flags |= RTM_F_TRAP; 1859 if (fri->offload_failed) 1860 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1861 1862 nlmsg_end(skb, nlh); 1863 return 0; 1864 1865 nla_put_failure: 1866 nlmsg_cancel(skb, nlh); 1867 return -EMSGSIZE; 1868 } 1869 1870 /* 1871 * Update FIB if: 1872 * - local address disappeared -> we must delete all the entries 1873 * referring to it. 1874 * - device went down -> we must shutdown all nexthops going via it. 1875 */ 1876 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1877 { 1878 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1879 struct net *net = dev_net(dev); 1880 struct hlist_head *head; 1881 struct fib_info *fi; 1882 int ret = 0; 1883 1884 if (!fib_info_laddrhash || local == 0) 1885 return 0; 1886 1887 head = fib_info_laddrhash_bucket(net, local); 1888 hlist_for_each_entry(fi, head, fib_lhash) { 1889 if (!net_eq(fi->fib_net, net) || 1890 fi->fib_tb_id != tb_id) 1891 continue; 1892 if (fi->fib_prefsrc == local) { 1893 fi->fib_flags |= RTNH_F_DEAD; 1894 fi->pfsrc_removed = true; 1895 ret++; 1896 } 1897 } 1898 return ret; 1899 } 1900 1901 static int call_fib_nh_notifiers(struct fib_nh *nh, 1902 enum fib_event_type event_type) 1903 { 1904 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1905 struct fib_nh_notifier_info info = { 1906 .fib_nh = nh, 1907 }; 1908 1909 switch (event_type) { 1910 case FIB_EVENT_NH_ADD: 1911 if (nh->fib_nh_flags & RTNH_F_DEAD) 1912 break; 1913 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1914 break; 1915 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1916 &info.info); 1917 case FIB_EVENT_NH_DEL: 1918 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1919 (nh->fib_nh_flags & RTNH_F_DEAD)) 1920 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1921 event_type, &info.info); 1922 break; 1923 default: 1924 break; 1925 } 1926 1927 return NOTIFY_DONE; 1928 } 1929 1930 /* Update the PMTU of exceptions when: 1931 * - the new MTU of the first hop becomes smaller than the PMTU 1932 * - the old MTU was the same as the PMTU, and it limited discovery of 1933 * larger MTUs on the path. With that limit raised, we can now 1934 * discover larger MTUs 1935 * A special case is locked exceptions, for which the PMTU is smaller 1936 * than the minimal accepted PMTU: 1937 * - if the new MTU is greater than the PMTU, don't make any change 1938 * - otherwise, unlock and set PMTU 1939 */ 1940 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1941 { 1942 struct fnhe_hash_bucket *bucket; 1943 int i; 1944 1945 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1946 if (!bucket) 1947 return; 1948 1949 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1950 struct fib_nh_exception *fnhe; 1951 1952 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1953 fnhe; 1954 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1955 if (fnhe->fnhe_mtu_locked) { 1956 if (new <= fnhe->fnhe_pmtu) { 1957 fnhe->fnhe_pmtu = new; 1958 fnhe->fnhe_mtu_locked = false; 1959 } 1960 } else if (new < fnhe->fnhe_pmtu || 1961 orig == fnhe->fnhe_pmtu) { 1962 fnhe->fnhe_pmtu = new; 1963 } 1964 } 1965 } 1966 } 1967 1968 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1969 { 1970 struct hlist_head *head = fib_info_devhash_bucket(dev); 1971 struct fib_nh *nh; 1972 1973 hlist_for_each_entry(nh, head, nh_hash) { 1974 if (nh->fib_nh_dev == dev) 1975 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1976 } 1977 } 1978 1979 /* Event force Flags Description 1980 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1981 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1982 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1983 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1984 * 1985 * only used when fib_nh is built into fib_info 1986 */ 1987 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1988 { 1989 struct hlist_head *head = fib_info_devhash_bucket(dev); 1990 struct fib_info *prev_fi = NULL; 1991 int scope = RT_SCOPE_NOWHERE; 1992 struct fib_nh *nh; 1993 int ret = 0; 1994 1995 if (force) 1996 scope = -1; 1997 1998 hlist_for_each_entry(nh, head, nh_hash) { 1999 struct fib_info *fi = nh->nh_parent; 2000 int dead; 2001 2002 BUG_ON(!fi->fib_nhs); 2003 if (nh->fib_nh_dev != dev || fi == prev_fi) 2004 continue; 2005 prev_fi = fi; 2006 dead = 0; 2007 change_nexthops(fi) { 2008 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2009 dead++; 2010 else if (nexthop_nh->fib_nh_dev == dev && 2011 nexthop_nh->fib_nh_scope != scope) { 2012 switch (event) { 2013 case NETDEV_DOWN: 2014 case NETDEV_UNREGISTER: 2015 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2016 fallthrough; 2017 case NETDEV_CHANGE: 2018 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2019 break; 2020 } 2021 call_fib_nh_notifiers(nexthop_nh, 2022 FIB_EVENT_NH_DEL); 2023 dead++; 2024 } 2025 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2026 if (event == NETDEV_UNREGISTER && 2027 nexthop_nh->fib_nh_dev == dev) { 2028 dead = fi->fib_nhs; 2029 break; 2030 } 2031 #endif 2032 } endfor_nexthops(fi) 2033 if (dead == fi->fib_nhs) { 2034 switch (event) { 2035 case NETDEV_DOWN: 2036 case NETDEV_UNREGISTER: 2037 fi->fib_flags |= RTNH_F_DEAD; 2038 fallthrough; 2039 case NETDEV_CHANGE: 2040 fi->fib_flags |= RTNH_F_LINKDOWN; 2041 break; 2042 } 2043 ret++; 2044 } 2045 2046 fib_rebalance(fi); 2047 } 2048 2049 return ret; 2050 } 2051 2052 /* Must be invoked inside of an RCU protected region. */ 2053 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2054 { 2055 struct fib_info *fi = NULL, *last_resort = NULL; 2056 struct hlist_head *fa_head = res->fa_head; 2057 struct fib_table *tb = res->table; 2058 u8 slen = 32 - res->prefixlen; 2059 int order = -1, last_idx = -1; 2060 struct fib_alias *fa, *fa1 = NULL; 2061 u32 last_prio = res->fi->fib_priority; 2062 dscp_t last_dscp = 0; 2063 2064 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2065 struct fib_info *next_fi = fa->fa_info; 2066 struct fib_nh_common *nhc; 2067 2068 if (fa->fa_slen != slen) 2069 continue; 2070 if (fa->fa_dscp && 2071 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos)) 2072 continue; 2073 if (fa->tb_id != tb->tb_id) 2074 continue; 2075 if (next_fi->fib_priority > last_prio && 2076 fa->fa_dscp == last_dscp) { 2077 if (last_dscp) 2078 continue; 2079 break; 2080 } 2081 if (next_fi->fib_flags & RTNH_F_DEAD) 2082 continue; 2083 last_dscp = fa->fa_dscp; 2084 last_prio = next_fi->fib_priority; 2085 2086 if (next_fi->fib_scope != res->scope || 2087 fa->fa_type != RTN_UNICAST) 2088 continue; 2089 2090 nhc = fib_info_nhc(next_fi, 0); 2091 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2092 continue; 2093 2094 fib_alias_accessed(fa); 2095 2096 if (!fi) { 2097 if (next_fi != res->fi) 2098 break; 2099 fa1 = fa; 2100 } else if (!fib_detect_death(fi, order, &last_resort, 2101 &last_idx, fa1->fa_default)) { 2102 fib_result_assign(res, fi); 2103 fa1->fa_default = order; 2104 goto out; 2105 } 2106 fi = next_fi; 2107 order++; 2108 } 2109 2110 if (order <= 0 || !fi) { 2111 if (fa1) 2112 fa1->fa_default = -1; 2113 goto out; 2114 } 2115 2116 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2117 fa1->fa_default)) { 2118 fib_result_assign(res, fi); 2119 fa1->fa_default = order; 2120 goto out; 2121 } 2122 2123 if (last_idx >= 0) 2124 fib_result_assign(res, last_resort); 2125 fa1->fa_default = last_idx; 2126 out: 2127 return; 2128 } 2129 2130 /* 2131 * Dead device goes up. We wake up dead nexthops. 2132 * It takes sense only on multipath routes. 2133 * 2134 * only used when fib_nh is built into fib_info 2135 */ 2136 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2137 { 2138 struct fib_info *prev_fi; 2139 struct hlist_head *head; 2140 struct fib_nh *nh; 2141 int ret; 2142 2143 if (!(dev->flags & IFF_UP)) 2144 return 0; 2145 2146 if (nh_flags & RTNH_F_DEAD) { 2147 unsigned int flags = dev_get_flags(dev); 2148 2149 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2150 nh_flags |= RTNH_F_LINKDOWN; 2151 } 2152 2153 prev_fi = NULL; 2154 head = fib_info_devhash_bucket(dev); 2155 ret = 0; 2156 2157 hlist_for_each_entry(nh, head, nh_hash) { 2158 struct fib_info *fi = nh->nh_parent; 2159 int alive; 2160 2161 BUG_ON(!fi->fib_nhs); 2162 if (nh->fib_nh_dev != dev || fi == prev_fi) 2163 continue; 2164 2165 prev_fi = fi; 2166 alive = 0; 2167 change_nexthops(fi) { 2168 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2169 alive++; 2170 continue; 2171 } 2172 if (!nexthop_nh->fib_nh_dev || 2173 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2174 continue; 2175 if (nexthop_nh->fib_nh_dev != dev || 2176 !__in_dev_get_rtnl(dev)) 2177 continue; 2178 alive++; 2179 nexthop_nh->fib_nh_flags &= ~nh_flags; 2180 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2181 } endfor_nexthops(fi) 2182 2183 if (alive > 0) { 2184 fi->fib_flags &= ~nh_flags; 2185 ret++; 2186 } 2187 2188 fib_rebalance(fi); 2189 } 2190 2191 return ret; 2192 } 2193 2194 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2195 static bool fib_good_nh(const struct fib_nh *nh) 2196 { 2197 int state = NUD_REACHABLE; 2198 2199 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2200 struct neighbour *n; 2201 2202 rcu_read_lock(); 2203 2204 if (likely(nh->fib_nh_gw_family == AF_INET)) 2205 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2206 (__force u32)nh->fib_nh_gw4); 2207 else if (nh->fib_nh_gw_family == AF_INET6) 2208 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2209 &nh->fib_nh_gw6); 2210 else 2211 n = NULL; 2212 if (n) 2213 state = READ_ONCE(n->nud_state); 2214 2215 rcu_read_unlock(); 2216 } 2217 2218 return !!(state & NUD_VALID); 2219 } 2220 2221 void fib_select_multipath(struct fib_result *res, int hash) 2222 { 2223 struct fib_info *fi = res->fi; 2224 struct net *net = fi->fib_net; 2225 bool first = false; 2226 2227 if (unlikely(res->fi->nh)) { 2228 nexthop_path_fib_result(res, hash); 2229 return; 2230 } 2231 2232 change_nexthops(fi) { 2233 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { 2234 if (!fib_good_nh(nexthop_nh)) 2235 continue; 2236 if (!first) { 2237 res->nh_sel = nhsel; 2238 res->nhc = &nexthop_nh->nh_common; 2239 first = true; 2240 } 2241 } 2242 2243 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2244 continue; 2245 2246 res->nh_sel = nhsel; 2247 res->nhc = &nexthop_nh->nh_common; 2248 return; 2249 } endfor_nexthops(fi); 2250 } 2251 #endif 2252 2253 void fib_select_path(struct net *net, struct fib_result *res, 2254 struct flowi4 *fl4, const struct sk_buff *skb) 2255 { 2256 if (fl4->flowi4_oif) 2257 goto check_saddr; 2258 2259 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2260 if (fib_info_num_path(res->fi) > 1) { 2261 int h = fib_multipath_hash(net, fl4, skb, NULL); 2262 2263 fib_select_multipath(res, h); 2264 } 2265 else 2266 #endif 2267 if (!res->prefixlen && 2268 res->table->tb_num_default > 1 && 2269 res->type == RTN_UNICAST) 2270 fib_select_default(fl4, res); 2271 2272 check_saddr: 2273 if (!fl4->saddr) 2274 fl4->saddr = fib_result_prefsrc(net, res); 2275 } 2276