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_hurry(&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 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 547 } 548 549 static int fib_detect_death(struct fib_info *fi, int order, 550 struct fib_info **last_resort, int *last_idx, 551 int dflt) 552 { 553 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 554 struct neighbour *n; 555 int state = NUD_NONE; 556 557 if (likely(nhc->nhc_gw_family == AF_INET)) 558 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 559 else if (nhc->nhc_gw_family == AF_INET6) 560 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 561 nhc->nhc_dev); 562 else 563 n = NULL; 564 565 if (n) { 566 state = READ_ONCE(n->nud_state); 567 neigh_release(n); 568 } else { 569 return 0; 570 } 571 if (state == NUD_REACHABLE) 572 return 0; 573 if ((state & NUD_VALID) && order != dflt) 574 return 0; 575 if ((state & NUD_VALID) || 576 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 577 *last_resort = fi; 578 *last_idx = order; 579 } 580 return 1; 581 } 582 583 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 584 struct nlattr *encap, u16 encap_type, 585 void *cfg, gfp_t gfp_flags, 586 struct netlink_ext_ack *extack) 587 { 588 int err; 589 590 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 591 gfp_flags); 592 if (!nhc->nhc_pcpu_rth_output) 593 return -ENOMEM; 594 595 if (encap) { 596 struct lwtunnel_state *lwtstate; 597 598 if (encap_type == LWTUNNEL_ENCAP_NONE) { 599 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 600 err = -EINVAL; 601 goto lwt_failure; 602 } 603 err = lwtunnel_build_state(net, encap_type, encap, 604 nhc->nhc_family, cfg, &lwtstate, 605 extack); 606 if (err) 607 goto lwt_failure; 608 609 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 610 } 611 612 return 0; 613 614 lwt_failure: 615 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 616 nhc->nhc_pcpu_rth_output = NULL; 617 return err; 618 } 619 EXPORT_SYMBOL_GPL(fib_nh_common_init); 620 621 int fib_nh_init(struct net *net, struct fib_nh *nh, 622 struct fib_config *cfg, int nh_weight, 623 struct netlink_ext_ack *extack) 624 { 625 int err; 626 627 nh->fib_nh_family = AF_INET; 628 629 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 630 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 631 if (err) 632 return err; 633 634 nh->fib_nh_oif = cfg->fc_oif; 635 nh->fib_nh_gw_family = cfg->fc_gw_family; 636 if (cfg->fc_gw_family == AF_INET) 637 nh->fib_nh_gw4 = cfg->fc_gw4; 638 else if (cfg->fc_gw_family == AF_INET6) 639 nh->fib_nh_gw6 = cfg->fc_gw6; 640 641 nh->fib_nh_flags = cfg->fc_flags; 642 643 #ifdef CONFIG_IP_ROUTE_CLASSID 644 nh->nh_tclassid = cfg->fc_flow; 645 if (nh->nh_tclassid) 646 atomic_inc(&net->ipv4.fib_num_tclassid_users); 647 #endif 648 #ifdef CONFIG_IP_ROUTE_MULTIPATH 649 nh->fib_nh_weight = nh_weight; 650 #endif 651 return 0; 652 } 653 654 #ifdef CONFIG_IP_ROUTE_MULTIPATH 655 656 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 657 struct netlink_ext_ack *extack) 658 { 659 int nhs = 0; 660 661 while (rtnh_ok(rtnh, remaining)) { 662 nhs++; 663 rtnh = rtnh_next(rtnh, &remaining); 664 } 665 666 /* leftover implies invalid nexthop configuration, discard it */ 667 if (remaining > 0) { 668 NL_SET_ERR_MSG(extack, 669 "Invalid nexthop configuration - extra data after nexthops"); 670 nhs = 0; 671 } 672 673 return nhs; 674 } 675 676 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 677 struct netlink_ext_ack *extack) 678 { 679 if (nla_len(nla) < sizeof(*gw)) { 680 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 681 return -EINVAL; 682 } 683 684 *gw = nla_get_in_addr(nla); 685 686 return 0; 687 } 688 689 /* only called when fib_nh is integrated into fib_info */ 690 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 691 int remaining, struct fib_config *cfg, 692 struct netlink_ext_ack *extack) 693 { 694 struct net *net = fi->fib_net; 695 struct fib_config fib_cfg; 696 struct fib_nh *nh; 697 int ret; 698 699 change_nexthops(fi) { 700 int attrlen; 701 702 memset(&fib_cfg, 0, sizeof(fib_cfg)); 703 704 if (!rtnh_ok(rtnh, remaining)) { 705 NL_SET_ERR_MSG(extack, 706 "Invalid nexthop configuration - extra data after nexthop"); 707 return -EINVAL; 708 } 709 710 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 711 NL_SET_ERR_MSG(extack, 712 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 713 return -EINVAL; 714 } 715 716 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 717 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 718 719 attrlen = rtnh_attrlen(rtnh); 720 if (attrlen > 0) { 721 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 722 723 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 724 nlav = nla_find(attrs, attrlen, RTA_VIA); 725 if (nla && nlav) { 726 NL_SET_ERR_MSG(extack, 727 "Nexthop configuration can not contain both GATEWAY and VIA"); 728 return -EINVAL; 729 } 730 if (nla) { 731 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 732 extack); 733 if (ret) 734 goto errout; 735 736 if (fib_cfg.fc_gw4) 737 fib_cfg.fc_gw_family = AF_INET; 738 } else if (nlav) { 739 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 740 if (ret) 741 goto errout; 742 } 743 744 nla = nla_find(attrs, attrlen, RTA_FLOW); 745 if (nla) { 746 if (nla_len(nla) < sizeof(u32)) { 747 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 748 return -EINVAL; 749 } 750 fib_cfg.fc_flow = nla_get_u32(nla); 751 } 752 753 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 754 /* RTA_ENCAP_TYPE length checked in 755 * lwtunnel_valid_encap_type_attr 756 */ 757 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 758 if (nla) 759 fib_cfg.fc_encap_type = nla_get_u16(nla); 760 } 761 762 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 763 rtnh->rtnh_hops + 1, extack); 764 if (ret) 765 goto errout; 766 767 rtnh = rtnh_next(rtnh, &remaining); 768 } endfor_nexthops(fi); 769 770 ret = -EINVAL; 771 nh = fib_info_nh(fi, 0); 772 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 773 NL_SET_ERR_MSG(extack, 774 "Nexthop device index does not match RTA_OIF"); 775 goto errout; 776 } 777 if (cfg->fc_gw_family) { 778 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 779 (cfg->fc_gw_family == AF_INET && 780 nh->fib_nh_gw4 != cfg->fc_gw4) || 781 (cfg->fc_gw_family == AF_INET6 && 782 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 783 NL_SET_ERR_MSG(extack, 784 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 785 goto errout; 786 } 787 } 788 #ifdef CONFIG_IP_ROUTE_CLASSID 789 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 790 NL_SET_ERR_MSG(extack, 791 "Nexthop class id does not match RTA_FLOW"); 792 goto errout; 793 } 794 #endif 795 ret = 0; 796 errout: 797 return ret; 798 } 799 800 /* only called when fib_nh is integrated into fib_info */ 801 static void fib_rebalance(struct fib_info *fi) 802 { 803 int total; 804 int w; 805 806 if (fib_info_num_path(fi) < 2) 807 return; 808 809 total = 0; 810 for_nexthops(fi) { 811 if (nh->fib_nh_flags & RTNH_F_DEAD) 812 continue; 813 814 if (ip_ignore_linkdown(nh->fib_nh_dev) && 815 nh->fib_nh_flags & RTNH_F_LINKDOWN) 816 continue; 817 818 total += nh->fib_nh_weight; 819 } endfor_nexthops(fi); 820 821 w = 0; 822 change_nexthops(fi) { 823 int upper_bound; 824 825 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 826 upper_bound = -1; 827 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 828 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 829 upper_bound = -1; 830 } else { 831 w += nexthop_nh->fib_nh_weight; 832 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 833 total) - 1; 834 } 835 836 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 837 } endfor_nexthops(fi); 838 } 839 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 840 841 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 842 int remaining, struct fib_config *cfg, 843 struct netlink_ext_ack *extack) 844 { 845 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 846 847 return -EINVAL; 848 } 849 850 #define fib_rebalance(fi) do { } while (0) 851 852 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 853 854 static int fib_encap_match(struct net *net, u16 encap_type, 855 struct nlattr *encap, 856 const struct fib_nh *nh, 857 const struct fib_config *cfg, 858 struct netlink_ext_ack *extack) 859 { 860 struct lwtunnel_state *lwtstate; 861 int ret, result = 0; 862 863 if (encap_type == LWTUNNEL_ENCAP_NONE) 864 return 0; 865 866 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 867 cfg, &lwtstate, extack); 868 if (!ret) { 869 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 870 lwtstate_free(lwtstate); 871 } 872 873 return result; 874 } 875 876 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 877 struct netlink_ext_ack *extack) 878 { 879 #ifdef CONFIG_IP_ROUTE_MULTIPATH 880 struct rtnexthop *rtnh; 881 int remaining; 882 #endif 883 884 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 885 return 1; 886 887 if (cfg->fc_nh_id) { 888 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 889 return 0; 890 return 1; 891 } 892 893 if (fi->nh) { 894 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 895 return 1; 896 return 0; 897 } 898 899 if (cfg->fc_oif || cfg->fc_gw_family) { 900 struct fib_nh *nh; 901 902 nh = fib_info_nh(fi, 0); 903 if (cfg->fc_encap) { 904 if (fib_encap_match(net, cfg->fc_encap_type, 905 cfg->fc_encap, nh, cfg, extack)) 906 return 1; 907 } 908 #ifdef CONFIG_IP_ROUTE_CLASSID 909 if (cfg->fc_flow && 910 cfg->fc_flow != nh->nh_tclassid) 911 return 1; 912 #endif 913 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 914 (cfg->fc_gw_family && 915 cfg->fc_gw_family != nh->fib_nh_gw_family)) 916 return 1; 917 918 if (cfg->fc_gw_family == AF_INET && 919 cfg->fc_gw4 != nh->fib_nh_gw4) 920 return 1; 921 922 if (cfg->fc_gw_family == AF_INET6 && 923 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 924 return 1; 925 926 return 0; 927 } 928 929 #ifdef CONFIG_IP_ROUTE_MULTIPATH 930 if (!cfg->fc_mp) 931 return 0; 932 933 rtnh = cfg->fc_mp; 934 remaining = cfg->fc_mp_len; 935 936 for_nexthops(fi) { 937 int attrlen; 938 939 if (!rtnh_ok(rtnh, remaining)) 940 return -EINVAL; 941 942 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 943 return 1; 944 945 attrlen = rtnh_attrlen(rtnh); 946 if (attrlen > 0) { 947 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 948 int err; 949 950 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 951 nlav = nla_find(attrs, attrlen, RTA_VIA); 952 if (nla && nlav) { 953 NL_SET_ERR_MSG(extack, 954 "Nexthop configuration can not contain both GATEWAY and VIA"); 955 return -EINVAL; 956 } 957 958 if (nla) { 959 __be32 gw; 960 961 err = fib_gw_from_attr(&gw, nla, extack); 962 if (err) 963 return err; 964 965 if (nh->fib_nh_gw_family != AF_INET || 966 gw != nh->fib_nh_gw4) 967 return 1; 968 } else if (nlav) { 969 struct fib_config cfg2; 970 971 err = fib_gw_from_via(&cfg2, nlav, extack); 972 if (err) 973 return err; 974 975 switch (nh->fib_nh_gw_family) { 976 case AF_INET: 977 if (cfg2.fc_gw_family != AF_INET || 978 cfg2.fc_gw4 != nh->fib_nh_gw4) 979 return 1; 980 break; 981 case AF_INET6: 982 if (cfg2.fc_gw_family != AF_INET6 || 983 ipv6_addr_cmp(&cfg2.fc_gw6, 984 &nh->fib_nh_gw6)) 985 return 1; 986 break; 987 } 988 } 989 990 #ifdef CONFIG_IP_ROUTE_CLASSID 991 nla = nla_find(attrs, attrlen, RTA_FLOW); 992 if (nla) { 993 if (nla_len(nla) < sizeof(u32)) { 994 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 995 return -EINVAL; 996 } 997 if (nla_get_u32(nla) != nh->nh_tclassid) 998 return 1; 999 } 1000 #endif 1001 } 1002 1003 rtnh = rtnh_next(rtnh, &remaining); 1004 } endfor_nexthops(fi); 1005 #endif 1006 return 0; 1007 } 1008 1009 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1010 { 1011 struct nlattr *nla; 1012 int remaining; 1013 1014 if (!cfg->fc_mx) 1015 return true; 1016 1017 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1018 int type = nla_type(nla); 1019 u32 fi_val, val; 1020 1021 if (!type) 1022 continue; 1023 if (type > RTAX_MAX) 1024 return false; 1025 1026 type = array_index_nospec(type, RTAX_MAX + 1); 1027 if (type == RTAX_CC_ALGO) { 1028 char tmp[TCP_CA_NAME_MAX]; 1029 bool ecn_ca = false; 1030 1031 nla_strscpy(tmp, nla, sizeof(tmp)); 1032 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 1033 } else { 1034 if (nla_len(nla) != sizeof(u32)) 1035 return false; 1036 val = nla_get_u32(nla); 1037 } 1038 1039 fi_val = fi->fib_metrics->metrics[type - 1]; 1040 if (type == RTAX_FEATURES) 1041 fi_val &= ~DST_FEATURE_ECN_CA; 1042 1043 if (fi_val != val) 1044 return false; 1045 } 1046 1047 return true; 1048 } 1049 1050 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1051 u32 table, struct netlink_ext_ack *extack) 1052 { 1053 struct fib6_config cfg = { 1054 .fc_table = table, 1055 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1056 .fc_ifindex = nh->fib_nh_oif, 1057 .fc_gateway = nh->fib_nh_gw6, 1058 }; 1059 struct fib6_nh fib6_nh = {}; 1060 int err; 1061 1062 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1063 if (!err) { 1064 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1065 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1066 GFP_KERNEL); 1067 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1068 nh->fib_nh_scope = RT_SCOPE_LINK; 1069 1070 ipv6_stub->fib6_nh_release(&fib6_nh); 1071 } 1072 1073 return err; 1074 } 1075 1076 /* 1077 * Picture 1078 * ------- 1079 * 1080 * Semantics of nexthop is very messy by historical reasons. 1081 * We have to take into account, that: 1082 * a) gateway can be actually local interface address, 1083 * so that gatewayed route is direct. 1084 * b) gateway must be on-link address, possibly 1085 * described not by an ifaddr, but also by a direct route. 1086 * c) If both gateway and interface are specified, they should not 1087 * contradict. 1088 * d) If we use tunnel routes, gateway could be not on-link. 1089 * 1090 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1091 * results in pretty ugly and hairy code with obscure logic. 1092 * 1093 * I chose to generalized it instead, so that the size 1094 * of code does not increase practically, but it becomes 1095 * much more general. 1096 * Every prefix is assigned a "scope" value: "host" is local address, 1097 * "link" is direct route, 1098 * [ ... "site" ... "interior" ... ] 1099 * and "universe" is true gateway route with global meaning. 1100 * 1101 * Every prefix refers to a set of "nexthop"s (gw, oif), 1102 * where gw must have narrower scope. This recursion stops 1103 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1104 * which means that gw is forced to be on link. 1105 * 1106 * Code is still hairy, but now it is apparently logically 1107 * consistent and very flexible. F.e. as by-product it allows 1108 * to co-exists in peace independent exterior and interior 1109 * routing processes. 1110 * 1111 * Normally it looks as following. 1112 * 1113 * {universe prefix} -> (gw, oif) [scope link] 1114 * | 1115 * |-> {link prefix} -> (gw, oif) [scope local] 1116 * | 1117 * |-> {local prefix} (terminal node) 1118 */ 1119 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1120 u8 scope, struct netlink_ext_ack *extack) 1121 { 1122 struct net_device *dev; 1123 struct fib_result res; 1124 int err = 0; 1125 1126 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1127 unsigned int addr_type; 1128 1129 if (scope >= RT_SCOPE_LINK) { 1130 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1131 return -EINVAL; 1132 } 1133 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1134 if (!dev) { 1135 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1136 return -ENODEV; 1137 } 1138 if (!(dev->flags & IFF_UP)) { 1139 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1140 return -ENETDOWN; 1141 } 1142 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1143 if (addr_type != RTN_UNICAST) { 1144 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1145 return -EINVAL; 1146 } 1147 if (!netif_carrier_ok(dev)) 1148 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1149 nh->fib_nh_dev = dev; 1150 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1151 nh->fib_nh_scope = RT_SCOPE_LINK; 1152 return 0; 1153 } 1154 rcu_read_lock(); 1155 { 1156 struct fib_table *tbl = NULL; 1157 struct flowi4 fl4 = { 1158 .daddr = nh->fib_nh_gw4, 1159 .flowi4_scope = scope + 1, 1160 .flowi4_oif = nh->fib_nh_oif, 1161 .flowi4_iif = LOOPBACK_IFINDEX, 1162 }; 1163 1164 /* It is not necessary, but requires a bit of thinking */ 1165 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1166 fl4.flowi4_scope = RT_SCOPE_LINK; 1167 1168 if (table && table != RT_TABLE_MAIN) 1169 tbl = fib_get_table(net, table); 1170 1171 if (tbl) 1172 err = fib_table_lookup(tbl, &fl4, &res, 1173 FIB_LOOKUP_IGNORE_LINKSTATE | 1174 FIB_LOOKUP_NOREF); 1175 1176 /* on error or if no table given do full lookup. This 1177 * is needed for example when nexthops are in the local 1178 * table rather than the given table 1179 */ 1180 if (!tbl || err) { 1181 err = fib_lookup(net, &fl4, &res, 1182 FIB_LOOKUP_IGNORE_LINKSTATE); 1183 } 1184 1185 if (err) { 1186 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1187 goto out; 1188 } 1189 } 1190 1191 err = -EINVAL; 1192 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1193 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1194 goto out; 1195 } 1196 nh->fib_nh_scope = res.scope; 1197 nh->fib_nh_oif = FIB_RES_OIF(res); 1198 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1199 if (!dev) { 1200 NL_SET_ERR_MSG(extack, 1201 "No egress device for nexthop gateway"); 1202 goto out; 1203 } 1204 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1205 if (!netif_carrier_ok(dev)) 1206 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1207 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1208 out: 1209 rcu_read_unlock(); 1210 return err; 1211 } 1212 1213 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1214 struct netlink_ext_ack *extack) 1215 { 1216 struct in_device *in_dev; 1217 int err; 1218 1219 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1220 NL_SET_ERR_MSG(extack, 1221 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1222 return -EINVAL; 1223 } 1224 1225 rcu_read_lock(); 1226 1227 err = -ENODEV; 1228 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1229 if (!in_dev) 1230 goto out; 1231 err = -ENETDOWN; 1232 if (!(in_dev->dev->flags & IFF_UP)) { 1233 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1234 goto out; 1235 } 1236 1237 nh->fib_nh_dev = in_dev->dev; 1238 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1239 nh->fib_nh_scope = RT_SCOPE_HOST; 1240 if (!netif_carrier_ok(nh->fib_nh_dev)) 1241 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1242 err = 0; 1243 out: 1244 rcu_read_unlock(); 1245 return err; 1246 } 1247 1248 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1249 struct netlink_ext_ack *extack) 1250 { 1251 int err; 1252 1253 if (nh->fib_nh_gw_family == AF_INET) 1254 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1255 else if (nh->fib_nh_gw_family == AF_INET6) 1256 err = fib_check_nh_v6_gw(net, nh, table, extack); 1257 else 1258 err = fib_check_nh_nongw(net, nh, extack); 1259 1260 return err; 1261 } 1262 1263 static struct hlist_head * 1264 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1265 { 1266 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1267 fib_info_hash_bits); 1268 1269 return &fib_info_laddrhash[slot]; 1270 } 1271 1272 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1273 struct hlist_head *new_laddrhash, 1274 unsigned int new_size) 1275 { 1276 struct hlist_head *old_info_hash, *old_laddrhash; 1277 unsigned int old_size = fib_info_hash_size; 1278 unsigned int i; 1279 1280 spin_lock_bh(&fib_info_lock); 1281 old_info_hash = fib_info_hash; 1282 old_laddrhash = fib_info_laddrhash; 1283 fib_info_hash_size = new_size; 1284 fib_info_hash_bits = ilog2(new_size); 1285 1286 for (i = 0; i < old_size; i++) { 1287 struct hlist_head *head = &fib_info_hash[i]; 1288 struct hlist_node *n; 1289 struct fib_info *fi; 1290 1291 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1292 struct hlist_head *dest; 1293 unsigned int new_hash; 1294 1295 new_hash = fib_info_hashfn(fi); 1296 dest = &new_info_hash[new_hash]; 1297 hlist_add_head(&fi->fib_hash, dest); 1298 } 1299 } 1300 fib_info_hash = new_info_hash; 1301 1302 fib_info_laddrhash = new_laddrhash; 1303 for (i = 0; i < old_size; i++) { 1304 struct hlist_head *lhead = &old_laddrhash[i]; 1305 struct hlist_node *n; 1306 struct fib_info *fi; 1307 1308 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1309 struct hlist_head *ldest; 1310 1311 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1312 fi->fib_prefsrc); 1313 hlist_add_head(&fi->fib_lhash, ldest); 1314 } 1315 } 1316 1317 spin_unlock_bh(&fib_info_lock); 1318 1319 kvfree(old_info_hash); 1320 kvfree(old_laddrhash); 1321 } 1322 1323 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1324 unsigned char scope) 1325 { 1326 struct fib_nh *nh; 1327 __be32 saddr; 1328 1329 if (nhc->nhc_family != AF_INET) 1330 return inet_select_addr(nhc->nhc_dev, 0, scope); 1331 1332 nh = container_of(nhc, struct fib_nh, nh_common); 1333 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1334 1335 WRITE_ONCE(nh->nh_saddr, saddr); 1336 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); 1337 1338 return saddr; 1339 } 1340 1341 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1342 { 1343 struct fib_nh_common *nhc = res->nhc; 1344 1345 if (res->fi->fib_prefsrc) 1346 return res->fi->fib_prefsrc; 1347 1348 if (nhc->nhc_family == AF_INET) { 1349 struct fib_nh *nh; 1350 1351 nh = container_of(nhc, struct fib_nh, nh_common); 1352 if (READ_ONCE(nh->nh_saddr_genid) == 1353 atomic_read(&net->ipv4.dev_addr_genid)) 1354 return READ_ONCE(nh->nh_saddr); 1355 } 1356 1357 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1358 } 1359 1360 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1361 { 1362 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1363 fib_prefsrc != cfg->fc_dst) { 1364 u32 tb_id = cfg->fc_table; 1365 int rc; 1366 1367 if (tb_id == RT_TABLE_MAIN) 1368 tb_id = RT_TABLE_LOCAL; 1369 1370 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1371 fib_prefsrc, tb_id); 1372 1373 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1374 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1375 fib_prefsrc, RT_TABLE_LOCAL); 1376 } 1377 1378 if (rc != RTN_LOCAL) 1379 return false; 1380 } 1381 return true; 1382 } 1383 1384 struct fib_info *fib_create_info(struct fib_config *cfg, 1385 struct netlink_ext_ack *extack) 1386 { 1387 int err; 1388 struct fib_info *fi = NULL; 1389 struct nexthop *nh = NULL; 1390 struct fib_info *ofi; 1391 int nhs = 1; 1392 struct net *net = cfg->fc_nlinfo.nl_net; 1393 1394 if (cfg->fc_type > RTN_MAX) 1395 goto err_inval; 1396 1397 /* Fast check to catch the most weird cases */ 1398 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1399 NL_SET_ERR_MSG(extack, "Invalid scope"); 1400 goto err_inval; 1401 } 1402 1403 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1404 NL_SET_ERR_MSG(extack, 1405 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1406 goto err_inval; 1407 } 1408 1409 if (cfg->fc_nh_id) { 1410 if (!cfg->fc_mx) { 1411 fi = fib_find_info_nh(net, cfg); 1412 if (fi) { 1413 refcount_inc(&fi->fib_treeref); 1414 return fi; 1415 } 1416 } 1417 1418 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1419 if (!nh) { 1420 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1421 goto err_inval; 1422 } 1423 nhs = 0; 1424 } 1425 1426 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1427 if (cfg->fc_mp) { 1428 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1429 if (nhs == 0) 1430 goto err_inval; 1431 } 1432 #endif 1433 1434 err = -ENOBUFS; 1435 1436 /* Paired with WRITE_ONCE() in fib_release_info() */ 1437 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1438 unsigned int new_size = fib_info_hash_size << 1; 1439 struct hlist_head *new_info_hash; 1440 struct hlist_head *new_laddrhash; 1441 size_t bytes; 1442 1443 if (!new_size) 1444 new_size = 16; 1445 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1446 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1447 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1448 if (!new_info_hash || !new_laddrhash) { 1449 kvfree(new_info_hash); 1450 kvfree(new_laddrhash); 1451 } else { 1452 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1453 } 1454 if (!fib_info_hash_size) 1455 goto failure; 1456 } 1457 1458 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1459 if (!fi) 1460 goto failure; 1461 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack); 1462 if (IS_ERR(fi->fib_metrics)) { 1463 err = PTR_ERR(fi->fib_metrics); 1464 kfree(fi); 1465 return ERR_PTR(err); 1466 } 1467 1468 fi->fib_net = net; 1469 fi->fib_protocol = cfg->fc_protocol; 1470 fi->fib_scope = cfg->fc_scope; 1471 fi->fib_flags = cfg->fc_flags; 1472 fi->fib_priority = cfg->fc_priority; 1473 fi->fib_prefsrc = cfg->fc_prefsrc; 1474 fi->fib_type = cfg->fc_type; 1475 fi->fib_tb_id = cfg->fc_table; 1476 1477 fi->fib_nhs = nhs; 1478 if (nh) { 1479 if (!nexthop_get(nh)) { 1480 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1481 err = -EINVAL; 1482 } else { 1483 err = 0; 1484 fi->nh = nh; 1485 } 1486 } else { 1487 change_nexthops(fi) { 1488 nexthop_nh->nh_parent = fi; 1489 } endfor_nexthops(fi) 1490 1491 if (cfg->fc_mp) 1492 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1493 extack); 1494 else 1495 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1496 } 1497 1498 if (err != 0) 1499 goto failure; 1500 1501 if (fib_props[cfg->fc_type].error) { 1502 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1503 NL_SET_ERR_MSG(extack, 1504 "Gateway, device and multipath can not be specified for this route type"); 1505 goto err_inval; 1506 } 1507 goto link_it; 1508 } else { 1509 switch (cfg->fc_type) { 1510 case RTN_UNICAST: 1511 case RTN_LOCAL: 1512 case RTN_BROADCAST: 1513 case RTN_ANYCAST: 1514 case RTN_MULTICAST: 1515 break; 1516 default: 1517 NL_SET_ERR_MSG(extack, "Invalid route type"); 1518 goto err_inval; 1519 } 1520 } 1521 1522 if (cfg->fc_scope > RT_SCOPE_HOST) { 1523 NL_SET_ERR_MSG(extack, "Invalid scope"); 1524 goto err_inval; 1525 } 1526 1527 if (fi->nh) { 1528 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1529 if (err) 1530 goto failure; 1531 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1532 struct fib_nh *nh = fi->fib_nh; 1533 1534 /* Local address is added. */ 1535 if (nhs != 1) { 1536 NL_SET_ERR_MSG(extack, 1537 "Route with host scope can not have multiple nexthops"); 1538 goto err_inval; 1539 } 1540 if (nh->fib_nh_gw_family) { 1541 NL_SET_ERR_MSG(extack, 1542 "Route with host scope can not have a gateway"); 1543 goto err_inval; 1544 } 1545 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1546 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1547 err = -ENODEV; 1548 if (!nh->fib_nh_dev) 1549 goto failure; 1550 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1551 GFP_KERNEL); 1552 } else { 1553 int linkdown = 0; 1554 1555 change_nexthops(fi) { 1556 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1557 cfg->fc_table, cfg->fc_scope, 1558 extack); 1559 if (err != 0) 1560 goto failure; 1561 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1562 linkdown++; 1563 } endfor_nexthops(fi) 1564 if (linkdown == fi->fib_nhs) 1565 fi->fib_flags |= RTNH_F_LINKDOWN; 1566 } 1567 1568 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1569 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1570 goto err_inval; 1571 } 1572 1573 if (!fi->nh) { 1574 change_nexthops(fi) { 1575 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1576 fi->fib_scope); 1577 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1578 fi->fib_nh_is_v6 = true; 1579 } endfor_nexthops(fi) 1580 1581 fib_rebalance(fi); 1582 } 1583 1584 link_it: 1585 ofi = fib_find_info(fi); 1586 if (ofi) { 1587 /* fib_table_lookup() should not see @fi yet. */ 1588 fi->fib_dead = 1; 1589 free_fib_info(fi); 1590 refcount_inc(&ofi->fib_treeref); 1591 return ofi; 1592 } 1593 1594 refcount_set(&fi->fib_treeref, 1); 1595 refcount_set(&fi->fib_clntref, 1); 1596 spin_lock_bh(&fib_info_lock); 1597 fib_info_cnt++; 1598 hlist_add_head(&fi->fib_hash, 1599 &fib_info_hash[fib_info_hashfn(fi)]); 1600 if (fi->fib_prefsrc) { 1601 struct hlist_head *head; 1602 1603 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1604 hlist_add_head(&fi->fib_lhash, head); 1605 } 1606 if (fi->nh) { 1607 list_add(&fi->nh_list, &nh->fi_list); 1608 } else { 1609 change_nexthops(fi) { 1610 struct hlist_head *head; 1611 1612 if (!nexthop_nh->fib_nh_dev) 1613 continue; 1614 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1615 hlist_add_head(&nexthop_nh->nh_hash, head); 1616 } endfor_nexthops(fi) 1617 } 1618 spin_unlock_bh(&fib_info_lock); 1619 return fi; 1620 1621 err_inval: 1622 err = -EINVAL; 1623 1624 failure: 1625 if (fi) { 1626 /* fib_table_lookup() should not see @fi yet. */ 1627 fi->fib_dead = 1; 1628 free_fib_info(fi); 1629 } 1630 1631 return ERR_PTR(err); 1632 } 1633 1634 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1635 u8 rt_family, unsigned char *flags, bool skip_oif) 1636 { 1637 if (nhc->nhc_flags & RTNH_F_DEAD) 1638 *flags |= RTNH_F_DEAD; 1639 1640 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1641 *flags |= RTNH_F_LINKDOWN; 1642 1643 rcu_read_lock(); 1644 switch (nhc->nhc_family) { 1645 case AF_INET: 1646 if (ip_ignore_linkdown(nhc->nhc_dev)) 1647 *flags |= RTNH_F_DEAD; 1648 break; 1649 case AF_INET6: 1650 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1651 *flags |= RTNH_F_DEAD; 1652 break; 1653 } 1654 rcu_read_unlock(); 1655 } 1656 1657 switch (nhc->nhc_gw_family) { 1658 case AF_INET: 1659 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1660 goto nla_put_failure; 1661 break; 1662 case AF_INET6: 1663 /* if gateway family does not match nexthop family 1664 * gateway is encoded as RTA_VIA 1665 */ 1666 if (rt_family != nhc->nhc_gw_family) { 1667 int alen = sizeof(struct in6_addr); 1668 struct nlattr *nla; 1669 struct rtvia *via; 1670 1671 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1672 if (!nla) 1673 goto nla_put_failure; 1674 1675 via = nla_data(nla); 1676 via->rtvia_family = AF_INET6; 1677 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1678 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1679 &nhc->nhc_gw.ipv6) < 0) { 1680 goto nla_put_failure; 1681 } 1682 break; 1683 } 1684 1685 *flags |= (nhc->nhc_flags & 1686 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1687 1688 if (!skip_oif && nhc->nhc_dev && 1689 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1690 goto nla_put_failure; 1691 1692 if (nhc->nhc_lwtstate && 1693 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1694 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1695 goto nla_put_failure; 1696 1697 return 0; 1698 1699 nla_put_failure: 1700 return -EMSGSIZE; 1701 } 1702 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1703 1704 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1705 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1706 int nh_weight, u8 rt_family, u32 nh_tclassid) 1707 { 1708 const struct net_device *dev = nhc->nhc_dev; 1709 struct rtnexthop *rtnh; 1710 unsigned char flags = 0; 1711 1712 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1713 if (!rtnh) 1714 goto nla_put_failure; 1715 1716 rtnh->rtnh_hops = nh_weight - 1; 1717 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1718 1719 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1720 goto nla_put_failure; 1721 1722 rtnh->rtnh_flags = flags; 1723 1724 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1725 goto nla_put_failure; 1726 1727 /* length of rtnetlink header + attributes */ 1728 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1729 1730 return 0; 1731 1732 nla_put_failure: 1733 return -EMSGSIZE; 1734 } 1735 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1736 #endif 1737 1738 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1739 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1740 { 1741 struct nlattr *mp; 1742 1743 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1744 if (!mp) 1745 goto nla_put_failure; 1746 1747 if (unlikely(fi->nh)) { 1748 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1749 goto nla_put_failure; 1750 goto mp_end; 1751 } 1752 1753 for_nexthops(fi) { 1754 u32 nh_tclassid = 0; 1755 #ifdef CONFIG_IP_ROUTE_CLASSID 1756 nh_tclassid = nh->nh_tclassid; 1757 #endif 1758 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1759 AF_INET, nh_tclassid) < 0) 1760 goto nla_put_failure; 1761 } endfor_nexthops(fi); 1762 1763 mp_end: 1764 nla_nest_end(skb, mp); 1765 1766 return 0; 1767 1768 nla_put_failure: 1769 return -EMSGSIZE; 1770 } 1771 #else 1772 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1773 { 1774 return 0; 1775 } 1776 #endif 1777 1778 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1779 const struct fib_rt_info *fri, unsigned int flags) 1780 { 1781 unsigned int nhs = fib_info_num_path(fri->fi); 1782 struct fib_info *fi = fri->fi; 1783 u32 tb_id = fri->tb_id; 1784 struct nlmsghdr *nlh; 1785 struct rtmsg *rtm; 1786 1787 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1788 if (!nlh) 1789 return -EMSGSIZE; 1790 1791 rtm = nlmsg_data(nlh); 1792 rtm->rtm_family = AF_INET; 1793 rtm->rtm_dst_len = fri->dst_len; 1794 rtm->rtm_src_len = 0; 1795 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); 1796 if (tb_id < 256) 1797 rtm->rtm_table = tb_id; 1798 else 1799 rtm->rtm_table = RT_TABLE_COMPAT; 1800 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1801 goto nla_put_failure; 1802 rtm->rtm_type = fri->type; 1803 rtm->rtm_flags = fi->fib_flags; 1804 rtm->rtm_scope = fi->fib_scope; 1805 rtm->rtm_protocol = fi->fib_protocol; 1806 1807 if (rtm->rtm_dst_len && 1808 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1809 goto nla_put_failure; 1810 if (fi->fib_priority && 1811 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1812 goto nla_put_failure; 1813 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1814 goto nla_put_failure; 1815 1816 if (fi->fib_prefsrc && 1817 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1818 goto nla_put_failure; 1819 1820 if (fi->nh) { 1821 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1822 goto nla_put_failure; 1823 if (nexthop_is_blackhole(fi->nh)) 1824 rtm->rtm_type = RTN_BLACKHOLE; 1825 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1826 goto offload; 1827 } 1828 1829 if (nhs == 1) { 1830 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1831 unsigned char flags = 0; 1832 1833 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1834 goto nla_put_failure; 1835 1836 rtm->rtm_flags = flags; 1837 #ifdef CONFIG_IP_ROUTE_CLASSID 1838 if (nhc->nhc_family == AF_INET) { 1839 struct fib_nh *nh; 1840 1841 nh = container_of(nhc, struct fib_nh, nh_common); 1842 if (nh->nh_tclassid && 1843 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1844 goto nla_put_failure; 1845 } 1846 #endif 1847 } else { 1848 if (fib_add_multipath(skb, fi) < 0) 1849 goto nla_put_failure; 1850 } 1851 1852 offload: 1853 if (fri->offload) 1854 rtm->rtm_flags |= RTM_F_OFFLOAD; 1855 if (fri->trap) 1856 rtm->rtm_flags |= RTM_F_TRAP; 1857 if (fri->offload_failed) 1858 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1859 1860 nlmsg_end(skb, nlh); 1861 return 0; 1862 1863 nla_put_failure: 1864 nlmsg_cancel(skb, nlh); 1865 return -EMSGSIZE; 1866 } 1867 1868 /* 1869 * Update FIB if: 1870 * - local address disappeared -> we must delete all the entries 1871 * referring to it. 1872 * - device went down -> we must shutdown all nexthops going via it. 1873 */ 1874 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1875 { 1876 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1877 struct net *net = dev_net(dev); 1878 struct hlist_head *head; 1879 struct fib_info *fi; 1880 int ret = 0; 1881 1882 if (!fib_info_laddrhash || local == 0) 1883 return 0; 1884 1885 head = fib_info_laddrhash_bucket(net, local); 1886 hlist_for_each_entry(fi, head, fib_lhash) { 1887 if (!net_eq(fi->fib_net, net) || 1888 fi->fib_tb_id != tb_id) 1889 continue; 1890 if (fi->fib_prefsrc == local) { 1891 fi->fib_flags |= RTNH_F_DEAD; 1892 fi->pfsrc_removed = true; 1893 ret++; 1894 } 1895 } 1896 return ret; 1897 } 1898 1899 static int call_fib_nh_notifiers(struct fib_nh *nh, 1900 enum fib_event_type event_type) 1901 { 1902 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1903 struct fib_nh_notifier_info info = { 1904 .fib_nh = nh, 1905 }; 1906 1907 switch (event_type) { 1908 case FIB_EVENT_NH_ADD: 1909 if (nh->fib_nh_flags & RTNH_F_DEAD) 1910 break; 1911 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1912 break; 1913 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1914 &info.info); 1915 case FIB_EVENT_NH_DEL: 1916 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1917 (nh->fib_nh_flags & RTNH_F_DEAD)) 1918 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1919 event_type, &info.info); 1920 break; 1921 default: 1922 break; 1923 } 1924 1925 return NOTIFY_DONE; 1926 } 1927 1928 /* Update the PMTU of exceptions when: 1929 * - the new MTU of the first hop becomes smaller than the PMTU 1930 * - the old MTU was the same as the PMTU, and it limited discovery of 1931 * larger MTUs on the path. With that limit raised, we can now 1932 * discover larger MTUs 1933 * A special case is locked exceptions, for which the PMTU is smaller 1934 * than the minimal accepted PMTU: 1935 * - if the new MTU is greater than the PMTU, don't make any change 1936 * - otherwise, unlock and set PMTU 1937 */ 1938 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1939 { 1940 struct fnhe_hash_bucket *bucket; 1941 int i; 1942 1943 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1944 if (!bucket) 1945 return; 1946 1947 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1948 struct fib_nh_exception *fnhe; 1949 1950 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1951 fnhe; 1952 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1953 if (fnhe->fnhe_mtu_locked) { 1954 if (new <= fnhe->fnhe_pmtu) { 1955 fnhe->fnhe_pmtu = new; 1956 fnhe->fnhe_mtu_locked = false; 1957 } 1958 } else if (new < fnhe->fnhe_pmtu || 1959 orig == fnhe->fnhe_pmtu) { 1960 fnhe->fnhe_pmtu = new; 1961 } 1962 } 1963 } 1964 } 1965 1966 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1967 { 1968 struct hlist_head *head = fib_info_devhash_bucket(dev); 1969 struct fib_nh *nh; 1970 1971 hlist_for_each_entry(nh, head, nh_hash) { 1972 if (nh->fib_nh_dev == dev) 1973 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1974 } 1975 } 1976 1977 /* Event force Flags Description 1978 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1979 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1980 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1981 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1982 * 1983 * only used when fib_nh is built into fib_info 1984 */ 1985 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1986 { 1987 struct hlist_head *head = fib_info_devhash_bucket(dev); 1988 struct fib_info *prev_fi = NULL; 1989 int scope = RT_SCOPE_NOWHERE; 1990 struct fib_nh *nh; 1991 int ret = 0; 1992 1993 if (force) 1994 scope = -1; 1995 1996 hlist_for_each_entry(nh, head, nh_hash) { 1997 struct fib_info *fi = nh->nh_parent; 1998 int dead; 1999 2000 BUG_ON(!fi->fib_nhs); 2001 if (nh->fib_nh_dev != dev || fi == prev_fi) 2002 continue; 2003 prev_fi = fi; 2004 dead = 0; 2005 change_nexthops(fi) { 2006 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2007 dead++; 2008 else if (nexthop_nh->fib_nh_dev == dev && 2009 nexthop_nh->fib_nh_scope != scope) { 2010 switch (event) { 2011 case NETDEV_DOWN: 2012 case NETDEV_UNREGISTER: 2013 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2014 fallthrough; 2015 case NETDEV_CHANGE: 2016 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2017 break; 2018 } 2019 call_fib_nh_notifiers(nexthop_nh, 2020 FIB_EVENT_NH_DEL); 2021 dead++; 2022 } 2023 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2024 if (event == NETDEV_UNREGISTER && 2025 nexthop_nh->fib_nh_dev == dev) { 2026 dead = fi->fib_nhs; 2027 break; 2028 } 2029 #endif 2030 } endfor_nexthops(fi) 2031 if (dead == fi->fib_nhs) { 2032 switch (event) { 2033 case NETDEV_DOWN: 2034 case NETDEV_UNREGISTER: 2035 fi->fib_flags |= RTNH_F_DEAD; 2036 fallthrough; 2037 case NETDEV_CHANGE: 2038 fi->fib_flags |= RTNH_F_LINKDOWN; 2039 break; 2040 } 2041 ret++; 2042 } 2043 2044 fib_rebalance(fi); 2045 } 2046 2047 return ret; 2048 } 2049 2050 /* Must be invoked inside of an RCU protected region. */ 2051 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2052 { 2053 struct fib_info *fi = NULL, *last_resort = NULL; 2054 struct hlist_head *fa_head = res->fa_head; 2055 struct fib_table *tb = res->table; 2056 u8 slen = 32 - res->prefixlen; 2057 int order = -1, last_idx = -1; 2058 struct fib_alias *fa, *fa1 = NULL; 2059 u32 last_prio = res->fi->fib_priority; 2060 dscp_t last_dscp = 0; 2061 2062 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2063 struct fib_info *next_fi = fa->fa_info; 2064 struct fib_nh_common *nhc; 2065 2066 if (fa->fa_slen != slen) 2067 continue; 2068 if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp)) 2069 continue; 2070 if (fa->tb_id != tb->tb_id) 2071 continue; 2072 if (next_fi->fib_priority > last_prio && 2073 fa->fa_dscp == last_dscp) { 2074 if (last_dscp) 2075 continue; 2076 break; 2077 } 2078 if (next_fi->fib_flags & RTNH_F_DEAD) 2079 continue; 2080 last_dscp = fa->fa_dscp; 2081 last_prio = next_fi->fib_priority; 2082 2083 if (next_fi->fib_scope != res->scope || 2084 fa->fa_type != RTN_UNICAST) 2085 continue; 2086 2087 nhc = fib_info_nhc(next_fi, 0); 2088 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2089 continue; 2090 2091 fib_alias_accessed(fa); 2092 2093 if (!fi) { 2094 if (next_fi != res->fi) 2095 break; 2096 fa1 = fa; 2097 } else if (!fib_detect_death(fi, order, &last_resort, 2098 &last_idx, fa1->fa_default)) { 2099 fib_result_assign(res, fi); 2100 fa1->fa_default = order; 2101 goto out; 2102 } 2103 fi = next_fi; 2104 order++; 2105 } 2106 2107 if (order <= 0 || !fi) { 2108 if (fa1) 2109 fa1->fa_default = -1; 2110 goto out; 2111 } 2112 2113 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2114 fa1->fa_default)) { 2115 fib_result_assign(res, fi); 2116 fa1->fa_default = order; 2117 goto out; 2118 } 2119 2120 if (last_idx >= 0) 2121 fib_result_assign(res, last_resort); 2122 fa1->fa_default = last_idx; 2123 out: 2124 return; 2125 } 2126 2127 /* 2128 * Dead device goes up. We wake up dead nexthops. 2129 * It takes sense only on multipath routes. 2130 * 2131 * only used when fib_nh is built into fib_info 2132 */ 2133 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2134 { 2135 struct fib_info *prev_fi; 2136 struct hlist_head *head; 2137 struct fib_nh *nh; 2138 int ret; 2139 2140 if (!(dev->flags & IFF_UP)) 2141 return 0; 2142 2143 if (nh_flags & RTNH_F_DEAD) { 2144 unsigned int flags = dev_get_flags(dev); 2145 2146 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2147 nh_flags |= RTNH_F_LINKDOWN; 2148 } 2149 2150 prev_fi = NULL; 2151 head = fib_info_devhash_bucket(dev); 2152 ret = 0; 2153 2154 hlist_for_each_entry(nh, head, nh_hash) { 2155 struct fib_info *fi = nh->nh_parent; 2156 int alive; 2157 2158 BUG_ON(!fi->fib_nhs); 2159 if (nh->fib_nh_dev != dev || fi == prev_fi) 2160 continue; 2161 2162 prev_fi = fi; 2163 alive = 0; 2164 change_nexthops(fi) { 2165 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2166 alive++; 2167 continue; 2168 } 2169 if (!nexthop_nh->fib_nh_dev || 2170 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2171 continue; 2172 if (nexthop_nh->fib_nh_dev != dev || 2173 !__in_dev_get_rtnl(dev)) 2174 continue; 2175 alive++; 2176 nexthop_nh->fib_nh_flags &= ~nh_flags; 2177 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2178 } endfor_nexthops(fi) 2179 2180 if (alive > 0) { 2181 fi->fib_flags &= ~nh_flags; 2182 ret++; 2183 } 2184 2185 fib_rebalance(fi); 2186 } 2187 2188 return ret; 2189 } 2190 2191 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2192 static bool fib_good_nh(const struct fib_nh *nh) 2193 { 2194 int state = NUD_REACHABLE; 2195 2196 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2197 struct neighbour *n; 2198 2199 rcu_read_lock(); 2200 2201 if (likely(nh->fib_nh_gw_family == AF_INET)) 2202 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2203 (__force u32)nh->fib_nh_gw4); 2204 else if (nh->fib_nh_gw_family == AF_INET6) 2205 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2206 &nh->fib_nh_gw6); 2207 else 2208 n = NULL; 2209 if (n) 2210 state = READ_ONCE(n->nud_state); 2211 2212 rcu_read_unlock(); 2213 } 2214 2215 return !!(state & NUD_VALID); 2216 } 2217 2218 void fib_select_multipath(struct fib_result *res, int hash) 2219 { 2220 struct fib_info *fi = res->fi; 2221 struct net *net = fi->fib_net; 2222 bool first = false; 2223 2224 if (unlikely(res->fi->nh)) { 2225 nexthop_path_fib_result(res, hash); 2226 return; 2227 } 2228 2229 change_nexthops(fi) { 2230 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { 2231 if (!fib_good_nh(nexthop_nh)) 2232 continue; 2233 if (!first) { 2234 res->nh_sel = nhsel; 2235 res->nhc = &nexthop_nh->nh_common; 2236 first = true; 2237 } 2238 } 2239 2240 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2241 continue; 2242 2243 res->nh_sel = nhsel; 2244 res->nhc = &nexthop_nh->nh_common; 2245 return; 2246 } endfor_nexthops(fi); 2247 } 2248 #endif 2249 2250 void fib_select_path(struct net *net, struct fib_result *res, 2251 struct flowi4 *fl4, const struct sk_buff *skb) 2252 { 2253 if (fl4->flowi4_oif) 2254 goto check_saddr; 2255 2256 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2257 if (fib_info_num_path(res->fi) > 1) { 2258 int h = fib_multipath_hash(net, fl4, skb, NULL); 2259 2260 fib_select_multipath(res, h); 2261 } 2262 else 2263 #endif 2264 if (!res->prefixlen && 2265 res->table->tb_num_default > 1 && 2266 res->type == RTN_UNICAST) 2267 fib_select_default(fl4, res); 2268 2269 check_saddr: 2270 if (!fl4->saddr) { 2271 struct net_device *l3mdev; 2272 2273 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev); 2274 2275 if (!l3mdev || 2276 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev) 2277 fl4->saddr = fib_result_prefsrc(net, res); 2278 else 2279 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK); 2280 } 2281 } 2282