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