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(const struct net *net, 351 unsigned int val) 352 { 353 return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits); 354 } 355 356 static inline unsigned int fib_info_hashfn(struct fib_info *fi) 357 { 358 unsigned int val; 359 360 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 361 fi->fib_scope, (__force u32)fi->fib_prefsrc, 362 fi->fib_priority); 363 364 if (fi->nh) { 365 val ^= fib_devindex_hashfn(fi->nh->id); 366 } else { 367 for_nexthops(fi) { 368 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 369 } endfor_nexthops(fi) 370 } 371 372 return fib_info_hashfn_result(fi->fib_net, val); 373 } 374 375 /* no metrics, only nexthop id */ 376 static struct fib_info *fib_find_info_nh(struct net *net, 377 const struct fib_config *cfg) 378 { 379 struct hlist_head *head; 380 struct fib_info *fi; 381 unsigned int hash; 382 383 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 384 cfg->fc_protocol, cfg->fc_scope, 385 (__force u32)cfg->fc_prefsrc, 386 cfg->fc_priority); 387 hash = fib_info_hashfn_result(net, hash); 388 head = &fib_info_hash[hash]; 389 390 hlist_for_each_entry(fi, head, fib_hash) { 391 if (!net_eq(fi->fib_net, net)) 392 continue; 393 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 394 continue; 395 if (cfg->fc_protocol == fi->fib_protocol && 396 cfg->fc_scope == fi->fib_scope && 397 cfg->fc_prefsrc == fi->fib_prefsrc && 398 cfg->fc_priority == fi->fib_priority && 399 cfg->fc_type == fi->fib_type && 400 cfg->fc_table == fi->fib_tb_id && 401 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 402 return fi; 403 } 404 405 return NULL; 406 } 407 408 static struct fib_info *fib_find_info(struct fib_info *nfi) 409 { 410 struct hlist_head *head; 411 struct fib_info *fi; 412 unsigned int hash; 413 414 hash = fib_info_hashfn(nfi); 415 head = &fib_info_hash[hash]; 416 417 hlist_for_each_entry(fi, head, fib_hash) { 418 if (!net_eq(fi->fib_net, nfi->fib_net)) 419 continue; 420 if (fi->fib_nhs != nfi->fib_nhs) 421 continue; 422 if (nfi->fib_protocol == fi->fib_protocol && 423 nfi->fib_scope == fi->fib_scope && 424 nfi->fib_prefsrc == fi->fib_prefsrc && 425 nfi->fib_priority == fi->fib_priority && 426 nfi->fib_type == fi->fib_type && 427 nfi->fib_tb_id == fi->fib_tb_id && 428 memcmp(nfi->fib_metrics, fi->fib_metrics, 429 sizeof(u32) * RTAX_MAX) == 0 && 430 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 431 nh_comp(fi, nfi) == 0) 432 return fi; 433 } 434 435 return NULL; 436 } 437 438 /* Check, that the gateway is already configured. 439 * Used only by redirect accept routine. 440 */ 441 int ip_fib_check_default(__be32 gw, struct net_device *dev) 442 { 443 struct hlist_head *head; 444 struct fib_nh *nh; 445 446 spin_lock(&fib_info_lock); 447 448 head = fib_info_devhash_bucket(dev); 449 450 hlist_for_each_entry(nh, head, nh_hash) { 451 if (nh->fib_nh_dev == dev && 452 nh->fib_nh_gw4 == gw && 453 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 454 spin_unlock(&fib_info_lock); 455 return 0; 456 } 457 } 458 459 spin_unlock(&fib_info_lock); 460 461 return -1; 462 } 463 464 size_t fib_nlmsg_size(struct fib_info *fi) 465 { 466 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 467 + nla_total_size(4) /* RTA_TABLE */ 468 + nla_total_size(4) /* RTA_DST */ 469 + nla_total_size(4) /* RTA_PRIORITY */ 470 + nla_total_size(4) /* RTA_PREFSRC */ 471 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 472 unsigned int nhs = fib_info_num_path(fi); 473 474 /* space for nested metrics */ 475 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 476 477 if (fi->nh) 478 payload += nla_total_size(4); /* RTA_NH_ID */ 479 480 if (nhs) { 481 size_t nh_encapsize = 0; 482 /* Also handles the special case nhs == 1 */ 483 484 /* each nexthop is packed in an attribute */ 485 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 486 unsigned int i; 487 488 /* may contain flow and gateway attribute */ 489 nhsize += 2 * nla_total_size(4); 490 491 /* grab encap info */ 492 for (i = 0; i < fib_info_num_path(fi); i++) { 493 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 494 495 if (nhc->nhc_lwtstate) { 496 /* RTA_ENCAP_TYPE */ 497 nh_encapsize += lwtunnel_get_encap_size( 498 nhc->nhc_lwtstate); 499 /* RTA_ENCAP */ 500 nh_encapsize += nla_total_size(2); 501 } 502 } 503 504 /* all nexthops are packed in a nested attribute */ 505 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 506 507 } 508 509 return payload; 510 } 511 512 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 513 int dst_len, u32 tb_id, const struct nl_info *info, 514 unsigned int nlm_flags) 515 { 516 struct fib_rt_info fri; 517 struct sk_buff *skb; 518 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 519 int err = -ENOBUFS; 520 521 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 522 if (!skb) 523 goto errout; 524 525 fri.fi = fa->fa_info; 526 fri.tb_id = tb_id; 527 fri.dst = key; 528 fri.dst_len = dst_len; 529 fri.dscp = fa->fa_dscp; 530 fri.type = fa->fa_type; 531 fri.offload = READ_ONCE(fa->offload); 532 fri.trap = READ_ONCE(fa->trap); 533 fri.offload_failed = READ_ONCE(fa->offload_failed); 534 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 535 if (err < 0) { 536 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 537 WARN_ON(err == -EMSGSIZE); 538 kfree_skb(skb); 539 goto errout; 540 } 541 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 542 info->nlh, GFP_KERNEL); 543 return; 544 errout: 545 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 546 } 547 548 static int fib_detect_death(struct fib_info *fi, int order, 549 struct fib_info **last_resort, int *last_idx, 550 int dflt) 551 { 552 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 553 struct neighbour *n; 554 int state = NUD_NONE; 555 556 if (likely(nhc->nhc_gw_family == AF_INET)) 557 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 558 else if (nhc->nhc_gw_family == AF_INET6) 559 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 560 nhc->nhc_dev); 561 else 562 n = NULL; 563 564 if (n) { 565 state = READ_ONCE(n->nud_state); 566 neigh_release(n); 567 } else { 568 return 0; 569 } 570 if (state == NUD_REACHABLE) 571 return 0; 572 if ((state & NUD_VALID) && order != dflt) 573 return 0; 574 if ((state & NUD_VALID) || 575 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 576 *last_resort = fi; 577 *last_idx = order; 578 } 579 return 1; 580 } 581 582 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 583 struct nlattr *encap, u16 encap_type, 584 void *cfg, gfp_t gfp_flags, 585 struct netlink_ext_ack *extack) 586 { 587 int err; 588 589 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 590 gfp_flags); 591 if (!nhc->nhc_pcpu_rth_output) 592 return -ENOMEM; 593 594 if (encap) { 595 struct lwtunnel_state *lwtstate; 596 597 if (encap_type == LWTUNNEL_ENCAP_NONE) { 598 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 599 err = -EINVAL; 600 goto lwt_failure; 601 } 602 err = lwtunnel_build_state(net, encap_type, encap, 603 nhc->nhc_family, cfg, &lwtstate, 604 extack); 605 if (err) 606 goto lwt_failure; 607 608 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 609 } 610 611 return 0; 612 613 lwt_failure: 614 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 615 nhc->nhc_pcpu_rth_output = NULL; 616 return err; 617 } 618 EXPORT_SYMBOL_GPL(fib_nh_common_init); 619 620 int fib_nh_init(struct net *net, struct fib_nh *nh, 621 struct fib_config *cfg, int nh_weight, 622 struct netlink_ext_ack *extack) 623 { 624 int err; 625 626 nh->fib_nh_family = AF_INET; 627 628 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 629 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 630 if (err) 631 return err; 632 633 nh->fib_nh_oif = cfg->fc_oif; 634 nh->fib_nh_gw_family = cfg->fc_gw_family; 635 if (cfg->fc_gw_family == AF_INET) 636 nh->fib_nh_gw4 = cfg->fc_gw4; 637 else if (cfg->fc_gw_family == AF_INET6) 638 nh->fib_nh_gw6 = cfg->fc_gw6; 639 640 nh->fib_nh_flags = cfg->fc_flags; 641 642 #ifdef CONFIG_IP_ROUTE_CLASSID 643 nh->nh_tclassid = cfg->fc_flow; 644 if (nh->nh_tclassid) 645 atomic_inc(&net->ipv4.fib_num_tclassid_users); 646 #endif 647 #ifdef CONFIG_IP_ROUTE_MULTIPATH 648 nh->fib_nh_weight = nh_weight; 649 #endif 650 return 0; 651 } 652 653 #ifdef CONFIG_IP_ROUTE_MULTIPATH 654 655 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 656 struct netlink_ext_ack *extack) 657 { 658 int nhs = 0; 659 660 while (rtnh_ok(rtnh, remaining)) { 661 nhs++; 662 rtnh = rtnh_next(rtnh, &remaining); 663 } 664 665 /* leftover implies invalid nexthop configuration, discard it */ 666 if (remaining > 0) { 667 NL_SET_ERR_MSG(extack, 668 "Invalid nexthop configuration - extra data after nexthops"); 669 nhs = 0; 670 } 671 672 return nhs; 673 } 674 675 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 676 struct netlink_ext_ack *extack) 677 { 678 if (nla_len(nla) < sizeof(*gw)) { 679 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 680 return -EINVAL; 681 } 682 683 *gw = nla_get_in_addr(nla); 684 685 return 0; 686 } 687 688 /* only called when fib_nh is integrated into fib_info */ 689 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 690 int remaining, struct fib_config *cfg, 691 struct netlink_ext_ack *extack) 692 { 693 struct net *net = fi->fib_net; 694 struct fib_config fib_cfg; 695 struct fib_nh *nh; 696 int ret; 697 698 change_nexthops(fi) { 699 int attrlen; 700 701 memset(&fib_cfg, 0, sizeof(fib_cfg)); 702 703 if (!rtnh_ok(rtnh, remaining)) { 704 NL_SET_ERR_MSG(extack, 705 "Invalid nexthop configuration - extra data after nexthop"); 706 return -EINVAL; 707 } 708 709 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 710 NL_SET_ERR_MSG(extack, 711 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 712 return -EINVAL; 713 } 714 715 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 716 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 717 718 attrlen = rtnh_attrlen(rtnh); 719 if (attrlen > 0) { 720 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 721 722 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 723 nlav = nla_find(attrs, attrlen, RTA_VIA); 724 if (nla && nlav) { 725 NL_SET_ERR_MSG(extack, 726 "Nexthop configuration can not contain both GATEWAY and VIA"); 727 return -EINVAL; 728 } 729 if (nla) { 730 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 731 extack); 732 if (ret) 733 goto errout; 734 735 if (fib_cfg.fc_gw4) 736 fib_cfg.fc_gw_family = AF_INET; 737 } else if (nlav) { 738 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 739 if (ret) 740 goto errout; 741 } 742 743 nla = nla_find(attrs, attrlen, RTA_FLOW); 744 if (nla) { 745 if (nla_len(nla) < sizeof(u32)) { 746 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 747 return -EINVAL; 748 } 749 fib_cfg.fc_flow = nla_get_u32(nla); 750 } 751 752 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 753 /* RTA_ENCAP_TYPE length checked in 754 * lwtunnel_valid_encap_type_attr 755 */ 756 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 757 if (nla) 758 fib_cfg.fc_encap_type = nla_get_u16(nla); 759 } 760 761 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 762 rtnh->rtnh_hops + 1, extack); 763 if (ret) 764 goto errout; 765 766 rtnh = rtnh_next(rtnh, &remaining); 767 } endfor_nexthops(fi); 768 769 ret = -EINVAL; 770 nh = fib_info_nh(fi, 0); 771 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 772 NL_SET_ERR_MSG(extack, 773 "Nexthop device index does not match RTA_OIF"); 774 goto errout; 775 } 776 if (cfg->fc_gw_family) { 777 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 778 (cfg->fc_gw_family == AF_INET && 779 nh->fib_nh_gw4 != cfg->fc_gw4) || 780 (cfg->fc_gw_family == AF_INET6 && 781 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 782 NL_SET_ERR_MSG(extack, 783 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 784 goto errout; 785 } 786 } 787 #ifdef CONFIG_IP_ROUTE_CLASSID 788 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 789 NL_SET_ERR_MSG(extack, 790 "Nexthop class id does not match RTA_FLOW"); 791 goto errout; 792 } 793 #endif 794 ret = 0; 795 errout: 796 return ret; 797 } 798 799 /* only called when fib_nh is integrated into fib_info */ 800 static void fib_rebalance(struct fib_info *fi) 801 { 802 int total; 803 int w; 804 805 if (fib_info_num_path(fi) < 2) 806 return; 807 808 total = 0; 809 for_nexthops(fi) { 810 if (nh->fib_nh_flags & RTNH_F_DEAD) 811 continue; 812 813 if (ip_ignore_linkdown(nh->fib_nh_dev) && 814 nh->fib_nh_flags & RTNH_F_LINKDOWN) 815 continue; 816 817 total += nh->fib_nh_weight; 818 } endfor_nexthops(fi); 819 820 w = 0; 821 change_nexthops(fi) { 822 int upper_bound; 823 824 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 825 upper_bound = -1; 826 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 827 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 828 upper_bound = -1; 829 } else { 830 w += nexthop_nh->fib_nh_weight; 831 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 832 total) - 1; 833 } 834 835 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 836 } endfor_nexthops(fi); 837 } 838 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 839 840 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 841 int remaining, struct fib_config *cfg, 842 struct netlink_ext_ack *extack) 843 { 844 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 845 846 return -EINVAL; 847 } 848 849 #define fib_rebalance(fi) do { } while (0) 850 851 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 852 853 static int fib_encap_match(struct net *net, u16 encap_type, 854 struct nlattr *encap, 855 const struct fib_nh *nh, 856 const struct fib_config *cfg, 857 struct netlink_ext_ack *extack) 858 { 859 struct lwtunnel_state *lwtstate; 860 int ret, result = 0; 861 862 if (encap_type == LWTUNNEL_ENCAP_NONE) 863 return 0; 864 865 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 866 cfg, &lwtstate, extack); 867 if (!ret) { 868 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 869 lwtstate_free(lwtstate); 870 } 871 872 return result; 873 } 874 875 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 876 struct netlink_ext_ack *extack) 877 { 878 #ifdef CONFIG_IP_ROUTE_MULTIPATH 879 struct rtnexthop *rtnh; 880 int remaining; 881 #endif 882 883 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 884 return 1; 885 886 if (cfg->fc_nh_id) { 887 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 888 return 0; 889 return 1; 890 } 891 892 if (fi->nh) { 893 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 894 return 1; 895 return 0; 896 } 897 898 if (cfg->fc_oif || cfg->fc_gw_family) { 899 struct fib_nh *nh; 900 901 nh = fib_info_nh(fi, 0); 902 if (cfg->fc_encap) { 903 if (fib_encap_match(net, cfg->fc_encap_type, 904 cfg->fc_encap, nh, cfg, extack)) 905 return 1; 906 } 907 #ifdef CONFIG_IP_ROUTE_CLASSID 908 if (cfg->fc_flow && 909 cfg->fc_flow != nh->nh_tclassid) 910 return 1; 911 #endif 912 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 913 (cfg->fc_gw_family && 914 cfg->fc_gw_family != nh->fib_nh_gw_family)) 915 return 1; 916 917 if (cfg->fc_gw_family == AF_INET && 918 cfg->fc_gw4 != nh->fib_nh_gw4) 919 return 1; 920 921 if (cfg->fc_gw_family == AF_INET6 && 922 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 923 return 1; 924 925 return 0; 926 } 927 928 #ifdef CONFIG_IP_ROUTE_MULTIPATH 929 if (!cfg->fc_mp) 930 return 0; 931 932 rtnh = cfg->fc_mp; 933 remaining = cfg->fc_mp_len; 934 935 for_nexthops(fi) { 936 int attrlen; 937 938 if (!rtnh_ok(rtnh, remaining)) 939 return -EINVAL; 940 941 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 942 return 1; 943 944 attrlen = rtnh_attrlen(rtnh); 945 if (attrlen > 0) { 946 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 947 int err; 948 949 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 950 nlav = nla_find(attrs, attrlen, RTA_VIA); 951 if (nla && nlav) { 952 NL_SET_ERR_MSG(extack, 953 "Nexthop configuration can not contain both GATEWAY and VIA"); 954 return -EINVAL; 955 } 956 957 if (nla) { 958 __be32 gw; 959 960 err = fib_gw_from_attr(&gw, nla, extack); 961 if (err) 962 return err; 963 964 if (nh->fib_nh_gw_family != AF_INET || 965 gw != nh->fib_nh_gw4) 966 return 1; 967 } else if (nlav) { 968 struct fib_config cfg2; 969 970 err = fib_gw_from_via(&cfg2, nlav, extack); 971 if (err) 972 return err; 973 974 switch (nh->fib_nh_gw_family) { 975 case AF_INET: 976 if (cfg2.fc_gw_family != AF_INET || 977 cfg2.fc_gw4 != nh->fib_nh_gw4) 978 return 1; 979 break; 980 case AF_INET6: 981 if (cfg2.fc_gw_family != AF_INET6 || 982 ipv6_addr_cmp(&cfg2.fc_gw6, 983 &nh->fib_nh_gw6)) 984 return 1; 985 break; 986 } 987 } 988 989 #ifdef CONFIG_IP_ROUTE_CLASSID 990 nla = nla_find(attrs, attrlen, RTA_FLOW); 991 if (nla) { 992 if (nla_len(nla) < sizeof(u32)) { 993 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 994 return -EINVAL; 995 } 996 if (nla_get_u32(nla) != nh->nh_tclassid) 997 return 1; 998 } 999 #endif 1000 } 1001 1002 rtnh = rtnh_next(rtnh, &remaining); 1003 } endfor_nexthops(fi); 1004 #endif 1005 return 0; 1006 } 1007 1008 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1009 { 1010 struct nlattr *nla; 1011 int remaining; 1012 1013 if (!cfg->fc_mx) 1014 return true; 1015 1016 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1017 int type = nla_type(nla); 1018 u32 fi_val, val; 1019 1020 if (!type) 1021 continue; 1022 if (type > RTAX_MAX) 1023 return false; 1024 1025 type = array_index_nospec(type, RTAX_MAX + 1); 1026 if (type == RTAX_CC_ALGO) { 1027 char tmp[TCP_CA_NAME_MAX]; 1028 bool ecn_ca = false; 1029 1030 nla_strscpy(tmp, nla, sizeof(tmp)); 1031 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 1032 } else { 1033 if (nla_len(nla) != sizeof(u32)) 1034 return false; 1035 val = nla_get_u32(nla); 1036 } 1037 1038 fi_val = fi->fib_metrics->metrics[type - 1]; 1039 if (type == RTAX_FEATURES) 1040 fi_val &= ~DST_FEATURE_ECN_CA; 1041 1042 if (fi_val != val) 1043 return false; 1044 } 1045 1046 return true; 1047 } 1048 1049 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1050 u32 table, struct netlink_ext_ack *extack) 1051 { 1052 struct fib6_config cfg = { 1053 .fc_table = table, 1054 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1055 .fc_ifindex = nh->fib_nh_oif, 1056 .fc_gateway = nh->fib_nh_gw6, 1057 }; 1058 struct fib6_nh fib6_nh = {}; 1059 int err; 1060 1061 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1062 if (!err) { 1063 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1064 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1065 GFP_KERNEL); 1066 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1067 nh->fib_nh_scope = RT_SCOPE_LINK; 1068 1069 ipv6_stub->fib6_nh_release(&fib6_nh); 1070 } 1071 1072 return err; 1073 } 1074 1075 /* 1076 * Picture 1077 * ------- 1078 * 1079 * Semantics of nexthop is very messy by historical reasons. 1080 * We have to take into account, that: 1081 * a) gateway can be actually local interface address, 1082 * so that gatewayed route is direct. 1083 * b) gateway must be on-link address, possibly 1084 * described not by an ifaddr, but also by a direct route. 1085 * c) If both gateway and interface are specified, they should not 1086 * contradict. 1087 * d) If we use tunnel routes, gateway could be not on-link. 1088 * 1089 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1090 * results in pretty ugly and hairy code with obscure logic. 1091 * 1092 * I chose to generalized it instead, so that the size 1093 * of code does not increase practically, but it becomes 1094 * much more general. 1095 * Every prefix is assigned a "scope" value: "host" is local address, 1096 * "link" is direct route, 1097 * [ ... "site" ... "interior" ... ] 1098 * and "universe" is true gateway route with global meaning. 1099 * 1100 * Every prefix refers to a set of "nexthop"s (gw, oif), 1101 * where gw must have narrower scope. This recursion stops 1102 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1103 * which means that gw is forced to be on link. 1104 * 1105 * Code is still hairy, but now it is apparently logically 1106 * consistent and very flexible. F.e. as by-product it allows 1107 * to co-exists in peace independent exterior and interior 1108 * routing processes. 1109 * 1110 * Normally it looks as following. 1111 * 1112 * {universe prefix} -> (gw, oif) [scope link] 1113 * | 1114 * |-> {link prefix} -> (gw, oif) [scope local] 1115 * | 1116 * |-> {local prefix} (terminal node) 1117 */ 1118 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1119 u8 scope, struct netlink_ext_ack *extack) 1120 { 1121 struct net_device *dev; 1122 struct fib_result res; 1123 int err = 0; 1124 1125 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1126 unsigned int addr_type; 1127 1128 if (scope >= RT_SCOPE_LINK) { 1129 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1130 return -EINVAL; 1131 } 1132 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1133 if (!dev) { 1134 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1135 return -ENODEV; 1136 } 1137 if (!(dev->flags & IFF_UP)) { 1138 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1139 return -ENETDOWN; 1140 } 1141 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1142 if (addr_type != RTN_UNICAST) { 1143 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1144 return -EINVAL; 1145 } 1146 if (!netif_carrier_ok(dev)) 1147 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1148 nh->fib_nh_dev = dev; 1149 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1150 nh->fib_nh_scope = RT_SCOPE_LINK; 1151 return 0; 1152 } 1153 rcu_read_lock(); 1154 { 1155 struct fib_table *tbl = NULL; 1156 struct flowi4 fl4 = { 1157 .daddr = nh->fib_nh_gw4, 1158 .flowi4_scope = scope + 1, 1159 .flowi4_oif = nh->fib_nh_oif, 1160 .flowi4_iif = LOOPBACK_IFINDEX, 1161 }; 1162 1163 /* It is not necessary, but requires a bit of thinking */ 1164 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1165 fl4.flowi4_scope = RT_SCOPE_LINK; 1166 1167 if (table && table != RT_TABLE_MAIN) 1168 tbl = fib_get_table(net, table); 1169 1170 if (tbl) 1171 err = fib_table_lookup(tbl, &fl4, &res, 1172 FIB_LOOKUP_IGNORE_LINKSTATE | 1173 FIB_LOOKUP_NOREF); 1174 1175 /* on error or if no table given do full lookup. This 1176 * is needed for example when nexthops are in the local 1177 * table rather than the given table 1178 */ 1179 if (!tbl || err) { 1180 err = fib_lookup(net, &fl4, &res, 1181 FIB_LOOKUP_IGNORE_LINKSTATE); 1182 } 1183 1184 if (err) { 1185 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1186 goto out; 1187 } 1188 } 1189 1190 err = -EINVAL; 1191 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1192 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1193 goto out; 1194 } 1195 nh->fib_nh_scope = res.scope; 1196 nh->fib_nh_oif = FIB_RES_OIF(res); 1197 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1198 if (!dev) { 1199 NL_SET_ERR_MSG(extack, 1200 "No egress device for nexthop gateway"); 1201 goto out; 1202 } 1203 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1204 if (!netif_carrier_ok(dev)) 1205 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1206 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1207 out: 1208 rcu_read_unlock(); 1209 return err; 1210 } 1211 1212 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1213 struct netlink_ext_ack *extack) 1214 { 1215 struct in_device *in_dev; 1216 int err; 1217 1218 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1219 NL_SET_ERR_MSG(extack, 1220 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1221 return -EINVAL; 1222 } 1223 1224 rcu_read_lock(); 1225 1226 err = -ENODEV; 1227 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1228 if (!in_dev) 1229 goto out; 1230 err = -ENETDOWN; 1231 if (!(in_dev->dev->flags & IFF_UP)) { 1232 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1233 goto out; 1234 } 1235 1236 nh->fib_nh_dev = in_dev->dev; 1237 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); 1238 nh->fib_nh_scope = RT_SCOPE_HOST; 1239 if (!netif_carrier_ok(nh->fib_nh_dev)) 1240 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1241 err = 0; 1242 out: 1243 rcu_read_unlock(); 1244 return err; 1245 } 1246 1247 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1248 struct netlink_ext_ack *extack) 1249 { 1250 int err; 1251 1252 if (nh->fib_nh_gw_family == AF_INET) 1253 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1254 else if (nh->fib_nh_gw_family == AF_INET6) 1255 err = fib_check_nh_v6_gw(net, nh, table, extack); 1256 else 1257 err = fib_check_nh_nongw(net, nh, extack); 1258 1259 return err; 1260 } 1261 1262 static struct hlist_head * 1263 fib_info_laddrhash_bucket(const struct net *net, __be32 val) 1264 { 1265 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, 1266 fib_info_hash_bits); 1267 1268 return &fib_info_laddrhash[slot]; 1269 } 1270 1271 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1272 struct hlist_head *new_laddrhash, 1273 unsigned int new_size) 1274 { 1275 struct hlist_head *old_info_hash, *old_laddrhash; 1276 unsigned int old_size = fib_info_hash_size; 1277 unsigned int i; 1278 1279 spin_lock_bh(&fib_info_lock); 1280 old_info_hash = fib_info_hash; 1281 old_laddrhash = fib_info_laddrhash; 1282 fib_info_hash_size = new_size; 1283 fib_info_hash_bits = ilog2(new_size); 1284 1285 for (i = 0; i < old_size; i++) { 1286 struct hlist_head *head = &fib_info_hash[i]; 1287 struct hlist_node *n; 1288 struct fib_info *fi; 1289 1290 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1291 struct hlist_head *dest; 1292 unsigned int new_hash; 1293 1294 new_hash = fib_info_hashfn(fi); 1295 dest = &new_info_hash[new_hash]; 1296 hlist_add_head(&fi->fib_hash, dest); 1297 } 1298 } 1299 fib_info_hash = new_info_hash; 1300 1301 fib_info_laddrhash = new_laddrhash; 1302 for (i = 0; i < old_size; i++) { 1303 struct hlist_head *lhead = &old_laddrhash[i]; 1304 struct hlist_node *n; 1305 struct fib_info *fi; 1306 1307 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1308 struct hlist_head *ldest; 1309 1310 ldest = fib_info_laddrhash_bucket(fi->fib_net, 1311 fi->fib_prefsrc); 1312 hlist_add_head(&fi->fib_lhash, ldest); 1313 } 1314 } 1315 1316 spin_unlock_bh(&fib_info_lock); 1317 1318 kvfree(old_info_hash); 1319 kvfree(old_laddrhash); 1320 } 1321 1322 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1323 unsigned char scope) 1324 { 1325 struct fib_nh *nh; 1326 __be32 saddr; 1327 1328 if (nhc->nhc_family != AF_INET) 1329 return inet_select_addr(nhc->nhc_dev, 0, scope); 1330 1331 nh = container_of(nhc, struct fib_nh, nh_common); 1332 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1333 1334 WRITE_ONCE(nh->nh_saddr, saddr); 1335 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); 1336 1337 return saddr; 1338 } 1339 1340 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1341 { 1342 struct fib_nh_common *nhc = res->nhc; 1343 1344 if (res->fi->fib_prefsrc) 1345 return res->fi->fib_prefsrc; 1346 1347 if (nhc->nhc_family == AF_INET) { 1348 struct fib_nh *nh; 1349 1350 nh = container_of(nhc, struct fib_nh, nh_common); 1351 if (READ_ONCE(nh->nh_saddr_genid) == 1352 atomic_read(&net->ipv4.dev_addr_genid)) 1353 return READ_ONCE(nh->nh_saddr); 1354 } 1355 1356 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1357 } 1358 1359 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1360 { 1361 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1362 fib_prefsrc != cfg->fc_dst) { 1363 u32 tb_id = cfg->fc_table; 1364 int rc; 1365 1366 if (tb_id == RT_TABLE_MAIN) 1367 tb_id = RT_TABLE_LOCAL; 1368 1369 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1370 fib_prefsrc, tb_id); 1371 1372 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1373 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1374 fib_prefsrc, RT_TABLE_LOCAL); 1375 } 1376 1377 if (rc != RTN_LOCAL) 1378 return false; 1379 } 1380 return true; 1381 } 1382 1383 struct fib_info *fib_create_info(struct fib_config *cfg, 1384 struct netlink_ext_ack *extack) 1385 { 1386 int err; 1387 struct fib_info *fi = NULL; 1388 struct nexthop *nh = NULL; 1389 struct fib_info *ofi; 1390 int nhs = 1; 1391 struct net *net = cfg->fc_nlinfo.nl_net; 1392 1393 if (cfg->fc_type > RTN_MAX) 1394 goto err_inval; 1395 1396 /* Fast check to catch the most weird cases */ 1397 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1398 NL_SET_ERR_MSG(extack, "Invalid scope"); 1399 goto err_inval; 1400 } 1401 1402 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1403 NL_SET_ERR_MSG(extack, 1404 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1405 goto err_inval; 1406 } 1407 1408 if (cfg->fc_nh_id) { 1409 if (!cfg->fc_mx) { 1410 fi = fib_find_info_nh(net, cfg); 1411 if (fi) { 1412 refcount_inc(&fi->fib_treeref); 1413 return fi; 1414 } 1415 } 1416 1417 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1418 if (!nh) { 1419 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1420 goto err_inval; 1421 } 1422 nhs = 0; 1423 } 1424 1425 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1426 if (cfg->fc_mp) { 1427 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1428 if (nhs == 0) 1429 goto err_inval; 1430 } 1431 #endif 1432 1433 err = -ENOBUFS; 1434 1435 /* Paired with WRITE_ONCE() in fib_release_info() */ 1436 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1437 unsigned int new_size = fib_info_hash_size << 1; 1438 struct hlist_head *new_info_hash; 1439 struct hlist_head *new_laddrhash; 1440 size_t bytes; 1441 1442 if (!new_size) 1443 new_size = 16; 1444 bytes = (size_t)new_size * sizeof(struct hlist_head *); 1445 new_info_hash = kvzalloc(bytes, GFP_KERNEL); 1446 new_laddrhash = kvzalloc(bytes, GFP_KERNEL); 1447 if (!new_info_hash || !new_laddrhash) { 1448 kvfree(new_info_hash); 1449 kvfree(new_laddrhash); 1450 } else { 1451 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1452 } 1453 if (!fib_info_hash_size) 1454 goto failure; 1455 } 1456 1457 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1458 if (!fi) 1459 goto failure; 1460 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack); 1461 if (IS_ERR(fi->fib_metrics)) { 1462 err = PTR_ERR(fi->fib_metrics); 1463 kfree(fi); 1464 return ERR_PTR(err); 1465 } 1466 1467 fi->fib_net = net; 1468 fi->fib_protocol = cfg->fc_protocol; 1469 fi->fib_scope = cfg->fc_scope; 1470 fi->fib_flags = cfg->fc_flags; 1471 fi->fib_priority = cfg->fc_priority; 1472 fi->fib_prefsrc = cfg->fc_prefsrc; 1473 fi->fib_type = cfg->fc_type; 1474 fi->fib_tb_id = cfg->fc_table; 1475 1476 fi->fib_nhs = nhs; 1477 if (nh) { 1478 if (!nexthop_get(nh)) { 1479 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1480 err = -EINVAL; 1481 } else { 1482 err = 0; 1483 fi->nh = nh; 1484 } 1485 } else { 1486 change_nexthops(fi) { 1487 nexthop_nh->nh_parent = fi; 1488 } endfor_nexthops(fi) 1489 1490 if (cfg->fc_mp) 1491 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1492 extack); 1493 else 1494 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1495 } 1496 1497 if (err != 0) 1498 goto failure; 1499 1500 if (fib_props[cfg->fc_type].error) { 1501 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1502 NL_SET_ERR_MSG(extack, 1503 "Gateway, device and multipath can not be specified for this route type"); 1504 goto err_inval; 1505 } 1506 goto link_it; 1507 } else { 1508 switch (cfg->fc_type) { 1509 case RTN_UNICAST: 1510 case RTN_LOCAL: 1511 case RTN_BROADCAST: 1512 case RTN_ANYCAST: 1513 case RTN_MULTICAST: 1514 break; 1515 default: 1516 NL_SET_ERR_MSG(extack, "Invalid route type"); 1517 goto err_inval; 1518 } 1519 } 1520 1521 if (cfg->fc_scope > RT_SCOPE_HOST) { 1522 NL_SET_ERR_MSG(extack, "Invalid scope"); 1523 goto err_inval; 1524 } 1525 1526 if (fi->nh) { 1527 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1528 if (err) 1529 goto failure; 1530 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1531 struct fib_nh *nh = fi->fib_nh; 1532 1533 /* Local address is added. */ 1534 if (nhs != 1) { 1535 NL_SET_ERR_MSG(extack, 1536 "Route with host scope can not have multiple nexthops"); 1537 goto err_inval; 1538 } 1539 if (nh->fib_nh_gw_family) { 1540 NL_SET_ERR_MSG(extack, 1541 "Route with host scope can not have a gateway"); 1542 goto err_inval; 1543 } 1544 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1545 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1546 err = -ENODEV; 1547 if (!nh->fib_nh_dev) 1548 goto failure; 1549 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, 1550 GFP_KERNEL); 1551 } else { 1552 int linkdown = 0; 1553 1554 change_nexthops(fi) { 1555 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1556 cfg->fc_table, cfg->fc_scope, 1557 extack); 1558 if (err != 0) 1559 goto failure; 1560 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1561 linkdown++; 1562 } endfor_nexthops(fi) 1563 if (linkdown == fi->fib_nhs) 1564 fi->fib_flags |= RTNH_F_LINKDOWN; 1565 } 1566 1567 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1568 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1569 goto err_inval; 1570 } 1571 1572 if (!fi->nh) { 1573 change_nexthops(fi) { 1574 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1575 fi->fib_scope); 1576 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1577 fi->fib_nh_is_v6 = true; 1578 } endfor_nexthops(fi) 1579 1580 fib_rebalance(fi); 1581 } 1582 1583 link_it: 1584 ofi = fib_find_info(fi); 1585 if (ofi) { 1586 /* fib_table_lookup() should not see @fi yet. */ 1587 fi->fib_dead = 1; 1588 free_fib_info(fi); 1589 refcount_inc(&ofi->fib_treeref); 1590 return ofi; 1591 } 1592 1593 refcount_set(&fi->fib_treeref, 1); 1594 refcount_set(&fi->fib_clntref, 1); 1595 spin_lock_bh(&fib_info_lock); 1596 fib_info_cnt++; 1597 hlist_add_head(&fi->fib_hash, 1598 &fib_info_hash[fib_info_hashfn(fi)]); 1599 if (fi->fib_prefsrc) { 1600 struct hlist_head *head; 1601 1602 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc); 1603 hlist_add_head(&fi->fib_lhash, head); 1604 } 1605 if (fi->nh) { 1606 list_add(&fi->nh_list, &nh->fi_list); 1607 } else { 1608 change_nexthops(fi) { 1609 struct hlist_head *head; 1610 1611 if (!nexthop_nh->fib_nh_dev) 1612 continue; 1613 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1614 hlist_add_head(&nexthop_nh->nh_hash, head); 1615 } endfor_nexthops(fi) 1616 } 1617 spin_unlock_bh(&fib_info_lock); 1618 return fi; 1619 1620 err_inval: 1621 err = -EINVAL; 1622 1623 failure: 1624 if (fi) { 1625 /* fib_table_lookup() should not see @fi yet. */ 1626 fi->fib_dead = 1; 1627 free_fib_info(fi); 1628 } 1629 1630 return ERR_PTR(err); 1631 } 1632 1633 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1634 u8 rt_family, unsigned char *flags, bool skip_oif) 1635 { 1636 if (nhc->nhc_flags & RTNH_F_DEAD) 1637 *flags |= RTNH_F_DEAD; 1638 1639 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1640 *flags |= RTNH_F_LINKDOWN; 1641 1642 rcu_read_lock(); 1643 switch (nhc->nhc_family) { 1644 case AF_INET: 1645 if (ip_ignore_linkdown(nhc->nhc_dev)) 1646 *flags |= RTNH_F_DEAD; 1647 break; 1648 case AF_INET6: 1649 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1650 *flags |= RTNH_F_DEAD; 1651 break; 1652 } 1653 rcu_read_unlock(); 1654 } 1655 1656 switch (nhc->nhc_gw_family) { 1657 case AF_INET: 1658 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1659 goto nla_put_failure; 1660 break; 1661 case AF_INET6: 1662 /* if gateway family does not match nexthop family 1663 * gateway is encoded as RTA_VIA 1664 */ 1665 if (rt_family != nhc->nhc_gw_family) { 1666 int alen = sizeof(struct in6_addr); 1667 struct nlattr *nla; 1668 struct rtvia *via; 1669 1670 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1671 if (!nla) 1672 goto nla_put_failure; 1673 1674 via = nla_data(nla); 1675 via->rtvia_family = AF_INET6; 1676 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1677 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1678 &nhc->nhc_gw.ipv6) < 0) { 1679 goto nla_put_failure; 1680 } 1681 break; 1682 } 1683 1684 *flags |= (nhc->nhc_flags & 1685 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1686 1687 if (!skip_oif && nhc->nhc_dev && 1688 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1689 goto nla_put_failure; 1690 1691 if (nhc->nhc_lwtstate && 1692 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1693 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1694 goto nla_put_failure; 1695 1696 return 0; 1697 1698 nla_put_failure: 1699 return -EMSGSIZE; 1700 } 1701 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1702 1703 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1704 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1705 int nh_weight, u8 rt_family, u32 nh_tclassid) 1706 { 1707 const struct net_device *dev = nhc->nhc_dev; 1708 struct rtnexthop *rtnh; 1709 unsigned char flags = 0; 1710 1711 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1712 if (!rtnh) 1713 goto nla_put_failure; 1714 1715 rtnh->rtnh_hops = nh_weight - 1; 1716 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1717 1718 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1719 goto nla_put_failure; 1720 1721 rtnh->rtnh_flags = flags; 1722 1723 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1724 goto nla_put_failure; 1725 1726 /* length of rtnetlink header + attributes */ 1727 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1728 1729 return 0; 1730 1731 nla_put_failure: 1732 return -EMSGSIZE; 1733 } 1734 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1735 #endif 1736 1737 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1738 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1739 { 1740 struct nlattr *mp; 1741 1742 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1743 if (!mp) 1744 goto nla_put_failure; 1745 1746 if (unlikely(fi->nh)) { 1747 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1748 goto nla_put_failure; 1749 goto mp_end; 1750 } 1751 1752 for_nexthops(fi) { 1753 u32 nh_tclassid = 0; 1754 #ifdef CONFIG_IP_ROUTE_CLASSID 1755 nh_tclassid = nh->nh_tclassid; 1756 #endif 1757 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1758 AF_INET, nh_tclassid) < 0) 1759 goto nla_put_failure; 1760 } endfor_nexthops(fi); 1761 1762 mp_end: 1763 nla_nest_end(skb, mp); 1764 1765 return 0; 1766 1767 nla_put_failure: 1768 return -EMSGSIZE; 1769 } 1770 #else 1771 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1772 { 1773 return 0; 1774 } 1775 #endif 1776 1777 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1778 const struct fib_rt_info *fri, unsigned int flags) 1779 { 1780 unsigned int nhs = fib_info_num_path(fri->fi); 1781 struct fib_info *fi = fri->fi; 1782 u32 tb_id = fri->tb_id; 1783 struct nlmsghdr *nlh; 1784 struct rtmsg *rtm; 1785 1786 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1787 if (!nlh) 1788 return -EMSGSIZE; 1789 1790 rtm = nlmsg_data(nlh); 1791 rtm->rtm_family = AF_INET; 1792 rtm->rtm_dst_len = fri->dst_len; 1793 rtm->rtm_src_len = 0; 1794 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); 1795 if (tb_id < 256) 1796 rtm->rtm_table = tb_id; 1797 else 1798 rtm->rtm_table = RT_TABLE_COMPAT; 1799 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1800 goto nla_put_failure; 1801 rtm->rtm_type = fri->type; 1802 rtm->rtm_flags = fi->fib_flags; 1803 rtm->rtm_scope = fi->fib_scope; 1804 rtm->rtm_protocol = fi->fib_protocol; 1805 1806 if (rtm->rtm_dst_len && 1807 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1808 goto nla_put_failure; 1809 if (fi->fib_priority && 1810 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1811 goto nla_put_failure; 1812 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1813 goto nla_put_failure; 1814 1815 if (fi->fib_prefsrc && 1816 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1817 goto nla_put_failure; 1818 1819 if (fi->nh) { 1820 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1821 goto nla_put_failure; 1822 if (nexthop_is_blackhole(fi->nh)) 1823 rtm->rtm_type = RTN_BLACKHOLE; 1824 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1825 goto offload; 1826 } 1827 1828 if (nhs == 1) { 1829 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1830 unsigned char flags = 0; 1831 1832 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1833 goto nla_put_failure; 1834 1835 rtm->rtm_flags = flags; 1836 #ifdef CONFIG_IP_ROUTE_CLASSID 1837 if (nhc->nhc_family == AF_INET) { 1838 struct fib_nh *nh; 1839 1840 nh = container_of(nhc, struct fib_nh, nh_common); 1841 if (nh->nh_tclassid && 1842 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1843 goto nla_put_failure; 1844 } 1845 #endif 1846 } else { 1847 if (fib_add_multipath(skb, fi) < 0) 1848 goto nla_put_failure; 1849 } 1850 1851 offload: 1852 if (fri->offload) 1853 rtm->rtm_flags |= RTM_F_OFFLOAD; 1854 if (fri->trap) 1855 rtm->rtm_flags |= RTM_F_TRAP; 1856 if (fri->offload_failed) 1857 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1858 1859 nlmsg_end(skb, nlh); 1860 return 0; 1861 1862 nla_put_failure: 1863 nlmsg_cancel(skb, nlh); 1864 return -EMSGSIZE; 1865 } 1866 1867 /* 1868 * Update FIB if: 1869 * - local address disappeared -> we must delete all the entries 1870 * referring to it. 1871 * - device went down -> we must shutdown all nexthops going via it. 1872 */ 1873 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1874 { 1875 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1876 struct net *net = dev_net(dev); 1877 struct hlist_head *head; 1878 struct fib_info *fi; 1879 int ret = 0; 1880 1881 if (!fib_info_laddrhash || local == 0) 1882 return 0; 1883 1884 head = fib_info_laddrhash_bucket(net, local); 1885 hlist_for_each_entry(fi, head, fib_lhash) { 1886 if (!net_eq(fi->fib_net, net) || 1887 fi->fib_tb_id != tb_id) 1888 continue; 1889 if (fi->fib_prefsrc == local) { 1890 fi->fib_flags |= RTNH_F_DEAD; 1891 fi->pfsrc_removed = true; 1892 ret++; 1893 } 1894 } 1895 return ret; 1896 } 1897 1898 static int call_fib_nh_notifiers(struct fib_nh *nh, 1899 enum fib_event_type event_type) 1900 { 1901 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1902 struct fib_nh_notifier_info info = { 1903 .fib_nh = nh, 1904 }; 1905 1906 switch (event_type) { 1907 case FIB_EVENT_NH_ADD: 1908 if (nh->fib_nh_flags & RTNH_F_DEAD) 1909 break; 1910 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1911 break; 1912 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1913 &info.info); 1914 case FIB_EVENT_NH_DEL: 1915 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1916 (nh->fib_nh_flags & RTNH_F_DEAD)) 1917 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1918 event_type, &info.info); 1919 break; 1920 default: 1921 break; 1922 } 1923 1924 return NOTIFY_DONE; 1925 } 1926 1927 /* Update the PMTU of exceptions when: 1928 * - the new MTU of the first hop becomes smaller than the PMTU 1929 * - the old MTU was the same as the PMTU, and it limited discovery of 1930 * larger MTUs on the path. With that limit raised, we can now 1931 * discover larger MTUs 1932 * A special case is locked exceptions, for which the PMTU is smaller 1933 * than the minimal accepted PMTU: 1934 * - if the new MTU is greater than the PMTU, don't make any change 1935 * - otherwise, unlock and set PMTU 1936 */ 1937 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1938 { 1939 struct fnhe_hash_bucket *bucket; 1940 int i; 1941 1942 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1943 if (!bucket) 1944 return; 1945 1946 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1947 struct fib_nh_exception *fnhe; 1948 1949 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1950 fnhe; 1951 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1952 if (fnhe->fnhe_mtu_locked) { 1953 if (new <= fnhe->fnhe_pmtu) { 1954 fnhe->fnhe_pmtu = new; 1955 fnhe->fnhe_mtu_locked = false; 1956 } 1957 } else if (new < fnhe->fnhe_pmtu || 1958 orig == fnhe->fnhe_pmtu) { 1959 fnhe->fnhe_pmtu = new; 1960 } 1961 } 1962 } 1963 } 1964 1965 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1966 { 1967 struct hlist_head *head = fib_info_devhash_bucket(dev); 1968 struct fib_nh *nh; 1969 1970 hlist_for_each_entry(nh, head, nh_hash) { 1971 if (nh->fib_nh_dev == dev) 1972 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1973 } 1974 } 1975 1976 /* Event force Flags Description 1977 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1978 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1979 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1980 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1981 * 1982 * only used when fib_nh is built into fib_info 1983 */ 1984 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1985 { 1986 struct hlist_head *head = fib_info_devhash_bucket(dev); 1987 struct fib_info *prev_fi = NULL; 1988 int scope = RT_SCOPE_NOWHERE; 1989 struct fib_nh *nh; 1990 int ret = 0; 1991 1992 if (force) 1993 scope = -1; 1994 1995 hlist_for_each_entry(nh, head, nh_hash) { 1996 struct fib_info *fi = nh->nh_parent; 1997 int dead; 1998 1999 BUG_ON(!fi->fib_nhs); 2000 if (nh->fib_nh_dev != dev || fi == prev_fi) 2001 continue; 2002 prev_fi = fi; 2003 dead = 0; 2004 change_nexthops(fi) { 2005 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2006 dead++; 2007 else if (nexthop_nh->fib_nh_dev == dev && 2008 nexthop_nh->fib_nh_scope != scope) { 2009 switch (event) { 2010 case NETDEV_DOWN: 2011 case NETDEV_UNREGISTER: 2012 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2013 fallthrough; 2014 case NETDEV_CHANGE: 2015 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2016 break; 2017 } 2018 call_fib_nh_notifiers(nexthop_nh, 2019 FIB_EVENT_NH_DEL); 2020 dead++; 2021 } 2022 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2023 if (event == NETDEV_UNREGISTER && 2024 nexthop_nh->fib_nh_dev == dev) { 2025 dead = fi->fib_nhs; 2026 break; 2027 } 2028 #endif 2029 } endfor_nexthops(fi) 2030 if (dead == fi->fib_nhs) { 2031 switch (event) { 2032 case NETDEV_DOWN: 2033 case NETDEV_UNREGISTER: 2034 fi->fib_flags |= RTNH_F_DEAD; 2035 fallthrough; 2036 case NETDEV_CHANGE: 2037 fi->fib_flags |= RTNH_F_LINKDOWN; 2038 break; 2039 } 2040 ret++; 2041 } 2042 2043 fib_rebalance(fi); 2044 } 2045 2046 return ret; 2047 } 2048 2049 /* Must be invoked inside of an RCU protected region. */ 2050 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2051 { 2052 struct fib_info *fi = NULL, *last_resort = NULL; 2053 struct hlist_head *fa_head = res->fa_head; 2054 struct fib_table *tb = res->table; 2055 u8 slen = 32 - res->prefixlen; 2056 int order = -1, last_idx = -1; 2057 struct fib_alias *fa, *fa1 = NULL; 2058 u32 last_prio = res->fi->fib_priority; 2059 dscp_t last_dscp = 0; 2060 2061 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2062 struct fib_info *next_fi = fa->fa_info; 2063 struct fib_nh_common *nhc; 2064 2065 if (fa->fa_slen != slen) 2066 continue; 2067 if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp)) 2068 continue; 2069 if (fa->tb_id != tb->tb_id) 2070 continue; 2071 if (next_fi->fib_priority > last_prio && 2072 fa->fa_dscp == last_dscp) { 2073 if (last_dscp) 2074 continue; 2075 break; 2076 } 2077 if (next_fi->fib_flags & RTNH_F_DEAD) 2078 continue; 2079 last_dscp = fa->fa_dscp; 2080 last_prio = next_fi->fib_priority; 2081 2082 if (next_fi->fib_scope != res->scope || 2083 fa->fa_type != RTN_UNICAST) 2084 continue; 2085 2086 nhc = fib_info_nhc(next_fi, 0); 2087 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2088 continue; 2089 2090 fib_alias_accessed(fa); 2091 2092 if (!fi) { 2093 if (next_fi != res->fi) 2094 break; 2095 fa1 = fa; 2096 } else if (!fib_detect_death(fi, order, &last_resort, 2097 &last_idx, fa1->fa_default)) { 2098 fib_result_assign(res, fi); 2099 fa1->fa_default = order; 2100 goto out; 2101 } 2102 fi = next_fi; 2103 order++; 2104 } 2105 2106 if (order <= 0 || !fi) { 2107 if (fa1) 2108 fa1->fa_default = -1; 2109 goto out; 2110 } 2111 2112 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2113 fa1->fa_default)) { 2114 fib_result_assign(res, fi); 2115 fa1->fa_default = order; 2116 goto out; 2117 } 2118 2119 if (last_idx >= 0) 2120 fib_result_assign(res, last_resort); 2121 fa1->fa_default = last_idx; 2122 out: 2123 return; 2124 } 2125 2126 /* 2127 * Dead device goes up. We wake up dead nexthops. 2128 * It takes sense only on multipath routes. 2129 * 2130 * only used when fib_nh is built into fib_info 2131 */ 2132 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2133 { 2134 struct fib_info *prev_fi; 2135 struct hlist_head *head; 2136 struct fib_nh *nh; 2137 int ret; 2138 2139 if (!(dev->flags & IFF_UP)) 2140 return 0; 2141 2142 if (nh_flags & RTNH_F_DEAD) { 2143 unsigned int flags = dev_get_flags(dev); 2144 2145 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2146 nh_flags |= RTNH_F_LINKDOWN; 2147 } 2148 2149 prev_fi = NULL; 2150 head = fib_info_devhash_bucket(dev); 2151 ret = 0; 2152 2153 hlist_for_each_entry(nh, head, nh_hash) { 2154 struct fib_info *fi = nh->nh_parent; 2155 int alive; 2156 2157 BUG_ON(!fi->fib_nhs); 2158 if (nh->fib_nh_dev != dev || fi == prev_fi) 2159 continue; 2160 2161 prev_fi = fi; 2162 alive = 0; 2163 change_nexthops(fi) { 2164 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2165 alive++; 2166 continue; 2167 } 2168 if (!nexthop_nh->fib_nh_dev || 2169 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2170 continue; 2171 if (nexthop_nh->fib_nh_dev != dev || 2172 !__in_dev_get_rtnl(dev)) 2173 continue; 2174 alive++; 2175 nexthop_nh->fib_nh_flags &= ~nh_flags; 2176 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2177 } endfor_nexthops(fi) 2178 2179 if (alive > 0) { 2180 fi->fib_flags &= ~nh_flags; 2181 ret++; 2182 } 2183 2184 fib_rebalance(fi); 2185 } 2186 2187 return ret; 2188 } 2189 2190 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2191 static bool fib_good_nh(const struct fib_nh *nh) 2192 { 2193 int state = NUD_REACHABLE; 2194 2195 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2196 struct neighbour *n; 2197 2198 rcu_read_lock(); 2199 2200 if (likely(nh->fib_nh_gw_family == AF_INET)) 2201 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2202 (__force u32)nh->fib_nh_gw4); 2203 else if (nh->fib_nh_gw_family == AF_INET6) 2204 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2205 &nh->fib_nh_gw6); 2206 else 2207 n = NULL; 2208 if (n) 2209 state = READ_ONCE(n->nud_state); 2210 2211 rcu_read_unlock(); 2212 } 2213 2214 return !!(state & NUD_VALID); 2215 } 2216 2217 void fib_select_multipath(struct fib_result *res, int hash) 2218 { 2219 struct fib_info *fi = res->fi; 2220 struct net *net = fi->fib_net; 2221 bool first = false; 2222 2223 if (unlikely(res->fi->nh)) { 2224 nexthop_path_fib_result(res, hash); 2225 return; 2226 } 2227 2228 change_nexthops(fi) { 2229 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { 2230 if (!fib_good_nh(nexthop_nh)) 2231 continue; 2232 if (!first) { 2233 res->nh_sel = nhsel; 2234 res->nhc = &nexthop_nh->nh_common; 2235 first = true; 2236 } 2237 } 2238 2239 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2240 continue; 2241 2242 res->nh_sel = nhsel; 2243 res->nhc = &nexthop_nh->nh_common; 2244 return; 2245 } endfor_nexthops(fi); 2246 } 2247 #endif 2248 2249 void fib_select_path(struct net *net, struct fib_result *res, 2250 struct flowi4 *fl4, const struct sk_buff *skb) 2251 { 2252 if (fl4->flowi4_oif) 2253 goto check_saddr; 2254 2255 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2256 if (fib_info_num_path(res->fi) > 1) { 2257 int h = fib_multipath_hash(net, fl4, skb, NULL); 2258 2259 fib_select_multipath(res, h); 2260 } 2261 else 2262 #endif 2263 if (!res->prefixlen && 2264 res->table->tb_num_default > 1 && 2265 res->type == RTN_UNICAST) 2266 fib_select_default(fl4, res); 2267 2268 check_saddr: 2269 if (!fl4->saddr) { 2270 struct net_device *l3mdev; 2271 2272 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev); 2273 2274 if (!l3mdev || 2275 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev) 2276 fl4->saddr = fib_result_prefsrc(net, res); 2277 else 2278 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK); 2279 } 2280 } 2281