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 33 #include <net/arp.h> 34 #include <net/ip.h> 35 #include <net/protocol.h> 36 #include <net/route.h> 37 #include <net/tcp.h> 38 #include <net/sock.h> 39 #include <net/ip_fib.h> 40 #include <net/ip6_fib.h> 41 #include <net/nexthop.h> 42 #include <net/netlink.h> 43 #include <net/rtnh.h> 44 #include <net/lwtunnel.h> 45 #include <net/fib_notifier.h> 46 #include <net/addrconf.h> 47 48 #include "fib_lookup.h" 49 50 static DEFINE_SPINLOCK(fib_info_lock); 51 static struct hlist_head *fib_info_hash; 52 static struct hlist_head *fib_info_laddrhash; 53 static unsigned int fib_info_hash_size; 54 static unsigned int fib_info_cnt; 55 56 #define DEVINDEX_HASHBITS 8 57 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 58 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 59 60 /* for_nexthops and change_nexthops only used when nexthop object 61 * is not set in a fib_info. The logic within can reference fib_nh. 62 */ 63 #ifdef CONFIG_IP_ROUTE_MULTIPATH 64 65 #define for_nexthops(fi) { \ 66 int nhsel; const struct fib_nh *nh; \ 67 for (nhsel = 0, nh = (fi)->fib_nh; \ 68 nhsel < fib_info_num_path((fi)); \ 69 nh++, nhsel++) 70 71 #define change_nexthops(fi) { \ 72 int nhsel; struct fib_nh *nexthop_nh; \ 73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 74 nhsel < fib_info_num_path((fi)); \ 75 nexthop_nh++, nhsel++) 76 77 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 78 79 /* Hope, that gcc will optimize it to get rid of dummy loop */ 80 81 #define for_nexthops(fi) { \ 82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 83 for (nhsel = 0; nhsel < 1; nhsel++) 84 85 #define change_nexthops(fi) { \ 86 int nhsel; \ 87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 88 for (nhsel = 0; nhsel < 1; nhsel++) 89 90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 91 92 #define endfor_nexthops(fi) } 93 94 95 const struct fib_prop fib_props[RTN_MAX + 1] = { 96 [RTN_UNSPEC] = { 97 .error = 0, 98 .scope = RT_SCOPE_NOWHERE, 99 }, 100 [RTN_UNICAST] = { 101 .error = 0, 102 .scope = RT_SCOPE_UNIVERSE, 103 }, 104 [RTN_LOCAL] = { 105 .error = 0, 106 .scope = RT_SCOPE_HOST, 107 }, 108 [RTN_BROADCAST] = { 109 .error = 0, 110 .scope = RT_SCOPE_LINK, 111 }, 112 [RTN_ANYCAST] = { 113 .error = 0, 114 .scope = RT_SCOPE_LINK, 115 }, 116 [RTN_MULTICAST] = { 117 .error = 0, 118 .scope = RT_SCOPE_UNIVERSE, 119 }, 120 [RTN_BLACKHOLE] = { 121 .error = -EINVAL, 122 .scope = RT_SCOPE_UNIVERSE, 123 }, 124 [RTN_UNREACHABLE] = { 125 .error = -EHOSTUNREACH, 126 .scope = RT_SCOPE_UNIVERSE, 127 }, 128 [RTN_PROHIBIT] = { 129 .error = -EACCES, 130 .scope = RT_SCOPE_UNIVERSE, 131 }, 132 [RTN_THROW] = { 133 .error = -EAGAIN, 134 .scope = RT_SCOPE_UNIVERSE, 135 }, 136 [RTN_NAT] = { 137 .error = -EINVAL, 138 .scope = RT_SCOPE_NOWHERE, 139 }, 140 [RTN_XRESOLVE] = { 141 .error = -EINVAL, 142 .scope = RT_SCOPE_NOWHERE, 143 }, 144 }; 145 146 static void rt_fibinfo_free(struct rtable __rcu **rtp) 147 { 148 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 149 150 if (!rt) 151 return; 152 153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 154 * because we waited an RCU grace period before calling 155 * free_fib_info_rcu() 156 */ 157 158 dst_dev_put(&rt->dst); 159 dst_release_immediate(&rt->dst); 160 } 161 162 static void free_nh_exceptions(struct fib_nh_common *nhc) 163 { 164 struct fnhe_hash_bucket *hash; 165 int i; 166 167 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); 168 if (!hash) 169 return; 170 for (i = 0; i < FNHE_HASH_SIZE; i++) { 171 struct fib_nh_exception *fnhe; 172 173 fnhe = rcu_dereference_protected(hash[i].chain, 1); 174 while (fnhe) { 175 struct fib_nh_exception *next; 176 177 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 178 179 rt_fibinfo_free(&fnhe->fnhe_rth_input); 180 rt_fibinfo_free(&fnhe->fnhe_rth_output); 181 182 kfree(fnhe); 183 184 fnhe = next; 185 } 186 } 187 kfree(hash); 188 } 189 190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 191 { 192 int cpu; 193 194 if (!rtp) 195 return; 196 197 for_each_possible_cpu(cpu) { 198 struct rtable *rt; 199 200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 201 if (rt) { 202 dst_dev_put(&rt->dst); 203 dst_release_immediate(&rt->dst); 204 } 205 } 206 free_percpu(rtp); 207 } 208 209 void fib_nh_common_release(struct fib_nh_common *nhc) 210 { 211 dev_put(nhc->nhc_dev); 212 lwtstate_put(nhc->nhc_lwtstate); 213 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 214 rt_fibinfo_free(&nhc->nhc_rth_input); 215 free_nh_exceptions(nhc); 216 } 217 EXPORT_SYMBOL_GPL(fib_nh_common_release); 218 219 void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 220 { 221 #ifdef CONFIG_IP_ROUTE_CLASSID 222 if (fib_nh->nh_tclassid) 223 atomic_dec(&net->ipv4.fib_num_tclassid_users); 224 #endif 225 fib_nh_common_release(&fib_nh->nh_common); 226 } 227 228 /* Release a nexthop info record */ 229 static void free_fib_info_rcu(struct rcu_head *head) 230 { 231 struct fib_info *fi = container_of(head, struct fib_info, rcu); 232 233 if (fi->nh) { 234 nexthop_put(fi->nh); 235 } else { 236 change_nexthops(fi) { 237 fib_nh_release(fi->fib_net, nexthop_nh); 238 } endfor_nexthops(fi); 239 } 240 241 ip_fib_metrics_put(fi->fib_metrics); 242 243 kfree(fi); 244 } 245 246 void free_fib_info(struct fib_info *fi) 247 { 248 if (fi->fib_dead == 0) { 249 pr_warn("Freeing alive fib_info %p\n", fi); 250 return; 251 } 252 fib_info_cnt--; 253 254 call_rcu(&fi->rcu, free_fib_info_rcu); 255 } 256 EXPORT_SYMBOL_GPL(free_fib_info); 257 258 void fib_release_info(struct fib_info *fi) 259 { 260 spin_lock_bh(&fib_info_lock); 261 if (fi && refcount_dec_and_test(&fi->fib_treeref)) { 262 hlist_del(&fi->fib_hash); 263 if (fi->fib_prefsrc) 264 hlist_del(&fi->fib_lhash); 265 if (fi->nh) { 266 list_del(&fi->nh_list); 267 } else { 268 change_nexthops(fi) { 269 if (!nexthop_nh->fib_nh_dev) 270 continue; 271 hlist_del(&nexthop_nh->nh_hash); 272 } endfor_nexthops(fi) 273 } 274 fi->fib_dead = 1; 275 fib_info_put(fi); 276 } 277 spin_unlock_bh(&fib_info_lock); 278 } 279 280 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 281 { 282 const struct fib_nh *onh; 283 284 if (fi->nh || ofi->nh) 285 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 286 287 if (ofi->fib_nhs == 0) 288 return 0; 289 290 for_nexthops(fi) { 291 onh = fib_info_nh(ofi, nhsel); 292 293 if (nh->fib_nh_oif != onh->fib_nh_oif || 294 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 295 nh->fib_nh_scope != onh->fib_nh_scope || 296 #ifdef CONFIG_IP_ROUTE_MULTIPATH 297 nh->fib_nh_weight != onh->fib_nh_weight || 298 #endif 299 #ifdef CONFIG_IP_ROUTE_CLASSID 300 nh->nh_tclassid != onh->nh_tclassid || 301 #endif 302 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 303 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 304 return -1; 305 306 if (nh->fib_nh_gw_family == AF_INET && 307 nh->fib_nh_gw4 != onh->fib_nh_gw4) 308 return -1; 309 310 if (nh->fib_nh_gw_family == AF_INET6 && 311 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 312 return -1; 313 } endfor_nexthops(fi); 314 return 0; 315 } 316 317 static inline unsigned int fib_devindex_hashfn(unsigned int val) 318 { 319 unsigned int mask = DEVINDEX_HASHSIZE - 1; 320 321 return (val ^ 322 (val >> DEVINDEX_HASHBITS) ^ 323 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 324 } 325 326 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 327 u32 prefsrc, u32 priority) 328 { 329 unsigned int val = init_val; 330 331 val ^= (protocol << 8) | scope; 332 val ^= prefsrc; 333 val ^= priority; 334 335 return val; 336 } 337 338 static unsigned int fib_info_hashfn_result(unsigned int val) 339 { 340 unsigned int mask = (fib_info_hash_size - 1); 341 342 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 343 } 344 345 static inline unsigned int fib_info_hashfn(struct fib_info *fi) 346 { 347 unsigned int val; 348 349 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 350 fi->fib_scope, (__force u32)fi->fib_prefsrc, 351 fi->fib_priority); 352 353 if (fi->nh) { 354 val ^= fib_devindex_hashfn(fi->nh->id); 355 } else { 356 for_nexthops(fi) { 357 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 358 } endfor_nexthops(fi) 359 } 360 361 return fib_info_hashfn_result(val); 362 } 363 364 /* no metrics, only nexthop id */ 365 static struct fib_info *fib_find_info_nh(struct net *net, 366 const struct fib_config *cfg) 367 { 368 struct hlist_head *head; 369 struct fib_info *fi; 370 unsigned int hash; 371 372 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 373 cfg->fc_protocol, cfg->fc_scope, 374 (__force u32)cfg->fc_prefsrc, 375 cfg->fc_priority); 376 hash = fib_info_hashfn_result(hash); 377 head = &fib_info_hash[hash]; 378 379 hlist_for_each_entry(fi, head, fib_hash) { 380 if (!net_eq(fi->fib_net, net)) 381 continue; 382 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 383 continue; 384 if (cfg->fc_protocol == fi->fib_protocol && 385 cfg->fc_scope == fi->fib_scope && 386 cfg->fc_prefsrc == fi->fib_prefsrc && 387 cfg->fc_priority == fi->fib_priority && 388 cfg->fc_type == fi->fib_type && 389 cfg->fc_table == fi->fib_tb_id && 390 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 391 return fi; 392 } 393 394 return NULL; 395 } 396 397 static struct fib_info *fib_find_info(struct fib_info *nfi) 398 { 399 struct hlist_head *head; 400 struct fib_info *fi; 401 unsigned int hash; 402 403 hash = fib_info_hashfn(nfi); 404 head = &fib_info_hash[hash]; 405 406 hlist_for_each_entry(fi, head, fib_hash) { 407 if (!net_eq(fi->fib_net, nfi->fib_net)) 408 continue; 409 if (fi->fib_nhs != nfi->fib_nhs) 410 continue; 411 if (nfi->fib_protocol == fi->fib_protocol && 412 nfi->fib_scope == fi->fib_scope && 413 nfi->fib_prefsrc == fi->fib_prefsrc && 414 nfi->fib_priority == fi->fib_priority && 415 nfi->fib_type == fi->fib_type && 416 memcmp(nfi->fib_metrics, fi->fib_metrics, 417 sizeof(u32) * RTAX_MAX) == 0 && 418 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 419 nh_comp(fi, nfi) == 0) 420 return fi; 421 } 422 423 return NULL; 424 } 425 426 /* Check, that the gateway is already configured. 427 * Used only by redirect accept routine. 428 */ 429 int ip_fib_check_default(__be32 gw, struct net_device *dev) 430 { 431 struct hlist_head *head; 432 struct fib_nh *nh; 433 unsigned int hash; 434 435 spin_lock(&fib_info_lock); 436 437 hash = fib_devindex_hashfn(dev->ifindex); 438 head = &fib_info_devhash[hash]; 439 hlist_for_each_entry(nh, head, nh_hash) { 440 if (nh->fib_nh_dev == dev && 441 nh->fib_nh_gw4 == gw && 442 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 443 spin_unlock(&fib_info_lock); 444 return 0; 445 } 446 } 447 448 spin_unlock(&fib_info_lock); 449 450 return -1; 451 } 452 453 size_t fib_nlmsg_size(struct fib_info *fi) 454 { 455 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 456 + nla_total_size(4) /* RTA_TABLE */ 457 + nla_total_size(4) /* RTA_DST */ 458 + nla_total_size(4) /* RTA_PRIORITY */ 459 + nla_total_size(4) /* RTA_PREFSRC */ 460 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 461 unsigned int nhs = fib_info_num_path(fi); 462 463 /* space for nested metrics */ 464 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 465 466 if (fi->nh) 467 payload += nla_total_size(4); /* RTA_NH_ID */ 468 469 if (nhs) { 470 size_t nh_encapsize = 0; 471 /* Also handles the special case nhs == 1 */ 472 473 /* each nexthop is packed in an attribute */ 474 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 475 unsigned int i; 476 477 /* may contain flow and gateway attribute */ 478 nhsize += 2 * nla_total_size(4); 479 480 /* grab encap info */ 481 for (i = 0; i < fib_info_num_path(fi); i++) { 482 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 483 484 if (nhc->nhc_lwtstate) { 485 /* RTA_ENCAP_TYPE */ 486 nh_encapsize += lwtunnel_get_encap_size( 487 nhc->nhc_lwtstate); 488 /* RTA_ENCAP */ 489 nh_encapsize += nla_total_size(2); 490 } 491 } 492 493 /* all nexthops are packed in a nested attribute */ 494 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 495 496 } 497 498 return payload; 499 } 500 501 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 502 int dst_len, u32 tb_id, const struct nl_info *info, 503 unsigned int nlm_flags) 504 { 505 struct fib_rt_info fri; 506 struct sk_buff *skb; 507 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 508 int err = -ENOBUFS; 509 510 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 511 if (!skb) 512 goto errout; 513 514 fri.fi = fa->fa_info; 515 fri.tb_id = tb_id; 516 fri.dst = key; 517 fri.dst_len = dst_len; 518 fri.tos = fa->fa_tos; 519 fri.type = fa->fa_type; 520 fri.offload = fa->offload; 521 fri.trap = fa->trap; 522 fri.offload_failed = fa->offload_failed; 523 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 524 if (err < 0) { 525 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 526 WARN_ON(err == -EMSGSIZE); 527 kfree_skb(skb); 528 goto errout; 529 } 530 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 531 info->nlh, GFP_KERNEL); 532 return; 533 errout: 534 if (err < 0) 535 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 536 } 537 538 static int fib_detect_death(struct fib_info *fi, int order, 539 struct fib_info **last_resort, int *last_idx, 540 int dflt) 541 { 542 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 543 struct neighbour *n; 544 int state = NUD_NONE; 545 546 if (likely(nhc->nhc_gw_family == AF_INET)) 547 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 548 else if (nhc->nhc_gw_family == AF_INET6) 549 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 550 nhc->nhc_dev); 551 else 552 n = NULL; 553 554 if (n) { 555 state = n->nud_state; 556 neigh_release(n); 557 } else { 558 return 0; 559 } 560 if (state == NUD_REACHABLE) 561 return 0; 562 if ((state & NUD_VALID) && order != dflt) 563 return 0; 564 if ((state & NUD_VALID) || 565 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 566 *last_resort = fi; 567 *last_idx = order; 568 } 569 return 1; 570 } 571 572 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 573 struct nlattr *encap, u16 encap_type, 574 void *cfg, gfp_t gfp_flags, 575 struct netlink_ext_ack *extack) 576 { 577 int err; 578 579 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 580 gfp_flags); 581 if (!nhc->nhc_pcpu_rth_output) 582 return -ENOMEM; 583 584 if (encap) { 585 struct lwtunnel_state *lwtstate; 586 587 if (encap_type == LWTUNNEL_ENCAP_NONE) { 588 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 589 err = -EINVAL; 590 goto lwt_failure; 591 } 592 err = lwtunnel_build_state(net, encap_type, encap, 593 nhc->nhc_family, cfg, &lwtstate, 594 extack); 595 if (err) 596 goto lwt_failure; 597 598 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 599 } 600 601 return 0; 602 603 lwt_failure: 604 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 605 nhc->nhc_pcpu_rth_output = NULL; 606 return err; 607 } 608 EXPORT_SYMBOL_GPL(fib_nh_common_init); 609 610 int fib_nh_init(struct net *net, struct fib_nh *nh, 611 struct fib_config *cfg, int nh_weight, 612 struct netlink_ext_ack *extack) 613 { 614 int err; 615 616 nh->fib_nh_family = AF_INET; 617 618 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 619 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 620 if (err) 621 return err; 622 623 nh->fib_nh_oif = cfg->fc_oif; 624 nh->fib_nh_gw_family = cfg->fc_gw_family; 625 if (cfg->fc_gw_family == AF_INET) 626 nh->fib_nh_gw4 = cfg->fc_gw4; 627 else if (cfg->fc_gw_family == AF_INET6) 628 nh->fib_nh_gw6 = cfg->fc_gw6; 629 630 nh->fib_nh_flags = cfg->fc_flags; 631 632 #ifdef CONFIG_IP_ROUTE_CLASSID 633 nh->nh_tclassid = cfg->fc_flow; 634 if (nh->nh_tclassid) 635 atomic_inc(&net->ipv4.fib_num_tclassid_users); 636 #endif 637 #ifdef CONFIG_IP_ROUTE_MULTIPATH 638 nh->fib_nh_weight = nh_weight; 639 #endif 640 return 0; 641 } 642 643 #ifdef CONFIG_IP_ROUTE_MULTIPATH 644 645 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 646 struct netlink_ext_ack *extack) 647 { 648 int nhs = 0; 649 650 while (rtnh_ok(rtnh, remaining)) { 651 nhs++; 652 rtnh = rtnh_next(rtnh, &remaining); 653 } 654 655 /* leftover implies invalid nexthop configuration, discard it */ 656 if (remaining > 0) { 657 NL_SET_ERR_MSG(extack, 658 "Invalid nexthop configuration - extra data after nexthops"); 659 nhs = 0; 660 } 661 662 return nhs; 663 } 664 665 /* only called when fib_nh is integrated into fib_info */ 666 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 667 int remaining, struct fib_config *cfg, 668 struct netlink_ext_ack *extack) 669 { 670 struct net *net = fi->fib_net; 671 struct fib_config fib_cfg; 672 struct fib_nh *nh; 673 int ret; 674 675 change_nexthops(fi) { 676 int attrlen; 677 678 memset(&fib_cfg, 0, sizeof(fib_cfg)); 679 680 if (!rtnh_ok(rtnh, remaining)) { 681 NL_SET_ERR_MSG(extack, 682 "Invalid nexthop configuration - extra data after nexthop"); 683 return -EINVAL; 684 } 685 686 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 687 NL_SET_ERR_MSG(extack, 688 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 689 return -EINVAL; 690 } 691 692 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 693 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 694 695 attrlen = rtnh_attrlen(rtnh); 696 if (attrlen > 0) { 697 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 698 699 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 700 nlav = nla_find(attrs, attrlen, RTA_VIA); 701 if (nla && nlav) { 702 NL_SET_ERR_MSG(extack, 703 "Nexthop configuration can not contain both GATEWAY and VIA"); 704 return -EINVAL; 705 } 706 if (nla) { 707 fib_cfg.fc_gw4 = nla_get_in_addr(nla); 708 if (fib_cfg.fc_gw4) 709 fib_cfg.fc_gw_family = AF_INET; 710 } else if (nlav) { 711 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 712 if (ret) 713 goto errout; 714 } 715 716 nla = nla_find(attrs, attrlen, RTA_FLOW); 717 if (nla) 718 fib_cfg.fc_flow = nla_get_u32(nla); 719 720 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 721 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 722 if (nla) 723 fib_cfg.fc_encap_type = nla_get_u16(nla); 724 } 725 726 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 727 rtnh->rtnh_hops + 1, extack); 728 if (ret) 729 goto errout; 730 731 rtnh = rtnh_next(rtnh, &remaining); 732 } endfor_nexthops(fi); 733 734 ret = -EINVAL; 735 nh = fib_info_nh(fi, 0); 736 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 737 NL_SET_ERR_MSG(extack, 738 "Nexthop device index does not match RTA_OIF"); 739 goto errout; 740 } 741 if (cfg->fc_gw_family) { 742 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 743 (cfg->fc_gw_family == AF_INET && 744 nh->fib_nh_gw4 != cfg->fc_gw4) || 745 (cfg->fc_gw_family == AF_INET6 && 746 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 747 NL_SET_ERR_MSG(extack, 748 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 749 goto errout; 750 } 751 } 752 #ifdef CONFIG_IP_ROUTE_CLASSID 753 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 754 NL_SET_ERR_MSG(extack, 755 "Nexthop class id does not match RTA_FLOW"); 756 goto errout; 757 } 758 #endif 759 ret = 0; 760 errout: 761 return ret; 762 } 763 764 /* only called when fib_nh is integrated into fib_info */ 765 static void fib_rebalance(struct fib_info *fi) 766 { 767 int total; 768 int w; 769 770 if (fib_info_num_path(fi) < 2) 771 return; 772 773 total = 0; 774 for_nexthops(fi) { 775 if (nh->fib_nh_flags & RTNH_F_DEAD) 776 continue; 777 778 if (ip_ignore_linkdown(nh->fib_nh_dev) && 779 nh->fib_nh_flags & RTNH_F_LINKDOWN) 780 continue; 781 782 total += nh->fib_nh_weight; 783 } endfor_nexthops(fi); 784 785 w = 0; 786 change_nexthops(fi) { 787 int upper_bound; 788 789 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 790 upper_bound = -1; 791 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 792 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 793 upper_bound = -1; 794 } else { 795 w += nexthop_nh->fib_nh_weight; 796 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 797 total) - 1; 798 } 799 800 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 801 } endfor_nexthops(fi); 802 } 803 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 804 805 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 806 int remaining, struct fib_config *cfg, 807 struct netlink_ext_ack *extack) 808 { 809 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 810 811 return -EINVAL; 812 } 813 814 #define fib_rebalance(fi) do { } while (0) 815 816 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 817 818 static int fib_encap_match(struct net *net, u16 encap_type, 819 struct nlattr *encap, 820 const struct fib_nh *nh, 821 const struct fib_config *cfg, 822 struct netlink_ext_ack *extack) 823 { 824 struct lwtunnel_state *lwtstate; 825 int ret, result = 0; 826 827 if (encap_type == LWTUNNEL_ENCAP_NONE) 828 return 0; 829 830 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 831 cfg, &lwtstate, extack); 832 if (!ret) { 833 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 834 lwtstate_free(lwtstate); 835 } 836 837 return result; 838 } 839 840 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 841 struct netlink_ext_ack *extack) 842 { 843 #ifdef CONFIG_IP_ROUTE_MULTIPATH 844 struct rtnexthop *rtnh; 845 int remaining; 846 #endif 847 848 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 849 return 1; 850 851 if (cfg->fc_nh_id) { 852 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 853 return 0; 854 return 1; 855 } 856 857 if (cfg->fc_oif || cfg->fc_gw_family) { 858 struct fib_nh *nh = fib_info_nh(fi, 0); 859 860 if (cfg->fc_encap) { 861 if (fib_encap_match(net, cfg->fc_encap_type, 862 cfg->fc_encap, nh, cfg, extack)) 863 return 1; 864 } 865 #ifdef CONFIG_IP_ROUTE_CLASSID 866 if (cfg->fc_flow && 867 cfg->fc_flow != nh->nh_tclassid) 868 return 1; 869 #endif 870 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 871 (cfg->fc_gw_family && 872 cfg->fc_gw_family != nh->fib_nh_gw_family)) 873 return 1; 874 875 if (cfg->fc_gw_family == AF_INET && 876 cfg->fc_gw4 != nh->fib_nh_gw4) 877 return 1; 878 879 if (cfg->fc_gw_family == AF_INET6 && 880 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 881 return 1; 882 883 return 0; 884 } 885 886 #ifdef CONFIG_IP_ROUTE_MULTIPATH 887 if (!cfg->fc_mp) 888 return 0; 889 890 rtnh = cfg->fc_mp; 891 remaining = cfg->fc_mp_len; 892 893 for_nexthops(fi) { 894 int attrlen; 895 896 if (!rtnh_ok(rtnh, remaining)) 897 return -EINVAL; 898 899 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 900 return 1; 901 902 attrlen = rtnh_attrlen(rtnh); 903 if (attrlen > 0) { 904 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 905 906 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 907 nlav = nla_find(attrs, attrlen, RTA_VIA); 908 if (nla && nlav) { 909 NL_SET_ERR_MSG(extack, 910 "Nexthop configuration can not contain both GATEWAY and VIA"); 911 return -EINVAL; 912 } 913 914 if (nla) { 915 if (nh->fib_nh_gw_family != AF_INET || 916 nla_get_in_addr(nla) != nh->fib_nh_gw4) 917 return 1; 918 } else if (nlav) { 919 struct fib_config cfg2; 920 int err; 921 922 err = fib_gw_from_via(&cfg2, nlav, extack); 923 if (err) 924 return err; 925 926 switch (nh->fib_nh_gw_family) { 927 case AF_INET: 928 if (cfg2.fc_gw_family != AF_INET || 929 cfg2.fc_gw4 != nh->fib_nh_gw4) 930 return 1; 931 break; 932 case AF_INET6: 933 if (cfg2.fc_gw_family != AF_INET6 || 934 ipv6_addr_cmp(&cfg2.fc_gw6, 935 &nh->fib_nh_gw6)) 936 return 1; 937 break; 938 } 939 } 940 941 #ifdef CONFIG_IP_ROUTE_CLASSID 942 nla = nla_find(attrs, attrlen, RTA_FLOW); 943 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 944 return 1; 945 #endif 946 } 947 948 rtnh = rtnh_next(rtnh, &remaining); 949 } endfor_nexthops(fi); 950 #endif 951 return 0; 952 } 953 954 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 955 { 956 struct nlattr *nla; 957 int remaining; 958 959 if (!cfg->fc_mx) 960 return true; 961 962 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 963 int type = nla_type(nla); 964 u32 fi_val, val; 965 966 if (!type) 967 continue; 968 if (type > RTAX_MAX) 969 return false; 970 971 if (type == RTAX_CC_ALGO) { 972 char tmp[TCP_CA_NAME_MAX]; 973 bool ecn_ca = false; 974 975 nla_strscpy(tmp, nla, sizeof(tmp)); 976 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 977 } else { 978 if (nla_len(nla) != sizeof(u32)) 979 return false; 980 val = nla_get_u32(nla); 981 } 982 983 fi_val = fi->fib_metrics->metrics[type - 1]; 984 if (type == RTAX_FEATURES) 985 fi_val &= ~DST_FEATURE_ECN_CA; 986 987 if (fi_val != val) 988 return false; 989 } 990 991 return true; 992 } 993 994 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 995 u32 table, struct netlink_ext_ack *extack) 996 { 997 struct fib6_config cfg = { 998 .fc_table = table, 999 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1000 .fc_ifindex = nh->fib_nh_oif, 1001 .fc_gateway = nh->fib_nh_gw6, 1002 }; 1003 struct fib6_nh fib6_nh = {}; 1004 int err; 1005 1006 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1007 if (!err) { 1008 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1009 dev_hold(nh->fib_nh_dev); 1010 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1011 nh->fib_nh_scope = RT_SCOPE_LINK; 1012 1013 ipv6_stub->fib6_nh_release(&fib6_nh); 1014 } 1015 1016 return err; 1017 } 1018 1019 /* 1020 * Picture 1021 * ------- 1022 * 1023 * Semantics of nexthop is very messy by historical reasons. 1024 * We have to take into account, that: 1025 * a) gateway can be actually local interface address, 1026 * so that gatewayed route is direct. 1027 * b) gateway must be on-link address, possibly 1028 * described not by an ifaddr, but also by a direct route. 1029 * c) If both gateway and interface are specified, they should not 1030 * contradict. 1031 * d) If we use tunnel routes, gateway could be not on-link. 1032 * 1033 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1034 * results in pretty ugly and hairy code with obscure logic. 1035 * 1036 * I chose to generalized it instead, so that the size 1037 * of code does not increase practically, but it becomes 1038 * much more general. 1039 * Every prefix is assigned a "scope" value: "host" is local address, 1040 * "link" is direct route, 1041 * [ ... "site" ... "interior" ... ] 1042 * and "universe" is true gateway route with global meaning. 1043 * 1044 * Every prefix refers to a set of "nexthop"s (gw, oif), 1045 * where gw must have narrower scope. This recursion stops 1046 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1047 * which means that gw is forced to be on link. 1048 * 1049 * Code is still hairy, but now it is apparently logically 1050 * consistent and very flexible. F.e. as by-product it allows 1051 * to co-exists in peace independent exterior and interior 1052 * routing processes. 1053 * 1054 * Normally it looks as following. 1055 * 1056 * {universe prefix} -> (gw, oif) [scope link] 1057 * | 1058 * |-> {link prefix} -> (gw, oif) [scope local] 1059 * | 1060 * |-> {local prefix} (terminal node) 1061 */ 1062 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1063 u8 scope, struct netlink_ext_ack *extack) 1064 { 1065 struct net_device *dev; 1066 struct fib_result res; 1067 int err = 0; 1068 1069 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1070 unsigned int addr_type; 1071 1072 if (scope >= RT_SCOPE_LINK) { 1073 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1074 return -EINVAL; 1075 } 1076 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1077 if (!dev) { 1078 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1079 return -ENODEV; 1080 } 1081 if (!(dev->flags & IFF_UP)) { 1082 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1083 return -ENETDOWN; 1084 } 1085 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1086 if (addr_type != RTN_UNICAST) { 1087 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1088 return -EINVAL; 1089 } 1090 if (!netif_carrier_ok(dev)) 1091 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1092 nh->fib_nh_dev = dev; 1093 dev_hold(dev); 1094 nh->fib_nh_scope = RT_SCOPE_LINK; 1095 return 0; 1096 } 1097 rcu_read_lock(); 1098 { 1099 struct fib_table *tbl = NULL; 1100 struct flowi4 fl4 = { 1101 .daddr = nh->fib_nh_gw4, 1102 .flowi4_scope = scope + 1, 1103 .flowi4_oif = nh->fib_nh_oif, 1104 .flowi4_iif = LOOPBACK_IFINDEX, 1105 }; 1106 1107 /* It is not necessary, but requires a bit of thinking */ 1108 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1109 fl4.flowi4_scope = RT_SCOPE_LINK; 1110 1111 if (table && table != RT_TABLE_MAIN) 1112 tbl = fib_get_table(net, table); 1113 1114 if (tbl) 1115 err = fib_table_lookup(tbl, &fl4, &res, 1116 FIB_LOOKUP_IGNORE_LINKSTATE | 1117 FIB_LOOKUP_NOREF); 1118 1119 /* on error or if no table given do full lookup. This 1120 * is needed for example when nexthops are in the local 1121 * table rather than the given table 1122 */ 1123 if (!tbl || err) { 1124 err = fib_lookup(net, &fl4, &res, 1125 FIB_LOOKUP_IGNORE_LINKSTATE); 1126 } 1127 1128 if (err) { 1129 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1130 goto out; 1131 } 1132 } 1133 1134 err = -EINVAL; 1135 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1136 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1137 goto out; 1138 } 1139 nh->fib_nh_scope = res.scope; 1140 nh->fib_nh_oif = FIB_RES_OIF(res); 1141 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1142 if (!dev) { 1143 NL_SET_ERR_MSG(extack, 1144 "No egress device for nexthop gateway"); 1145 goto out; 1146 } 1147 dev_hold(dev); 1148 if (!netif_carrier_ok(dev)) 1149 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1150 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1151 out: 1152 rcu_read_unlock(); 1153 return err; 1154 } 1155 1156 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1157 struct netlink_ext_ack *extack) 1158 { 1159 struct in_device *in_dev; 1160 int err; 1161 1162 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1163 NL_SET_ERR_MSG(extack, 1164 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1165 return -EINVAL; 1166 } 1167 1168 rcu_read_lock(); 1169 1170 err = -ENODEV; 1171 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1172 if (!in_dev) 1173 goto out; 1174 err = -ENETDOWN; 1175 if (!(in_dev->dev->flags & IFF_UP)) { 1176 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1177 goto out; 1178 } 1179 1180 nh->fib_nh_dev = in_dev->dev; 1181 dev_hold(nh->fib_nh_dev); 1182 nh->fib_nh_scope = RT_SCOPE_HOST; 1183 if (!netif_carrier_ok(nh->fib_nh_dev)) 1184 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1185 err = 0; 1186 out: 1187 rcu_read_unlock(); 1188 return err; 1189 } 1190 1191 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1192 struct netlink_ext_ack *extack) 1193 { 1194 int err; 1195 1196 if (nh->fib_nh_gw_family == AF_INET) 1197 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1198 else if (nh->fib_nh_gw_family == AF_INET6) 1199 err = fib_check_nh_v6_gw(net, nh, table, extack); 1200 else 1201 err = fib_check_nh_nongw(net, nh, extack); 1202 1203 return err; 1204 } 1205 1206 static inline unsigned int fib_laddr_hashfn(__be32 val) 1207 { 1208 unsigned int mask = (fib_info_hash_size - 1); 1209 1210 return ((__force u32)val ^ 1211 ((__force u32)val >> 7) ^ 1212 ((__force u32)val >> 14)) & mask; 1213 } 1214 1215 static struct hlist_head *fib_info_hash_alloc(int bytes) 1216 { 1217 if (bytes <= PAGE_SIZE) 1218 return kzalloc(bytes, GFP_KERNEL); 1219 else 1220 return (struct hlist_head *) 1221 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 1222 get_order(bytes)); 1223 } 1224 1225 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 1226 { 1227 if (!hash) 1228 return; 1229 1230 if (bytes <= PAGE_SIZE) 1231 kfree(hash); 1232 else 1233 free_pages((unsigned long) hash, get_order(bytes)); 1234 } 1235 1236 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1237 struct hlist_head *new_laddrhash, 1238 unsigned int new_size) 1239 { 1240 struct hlist_head *old_info_hash, *old_laddrhash; 1241 unsigned int old_size = fib_info_hash_size; 1242 unsigned int i, bytes; 1243 1244 spin_lock_bh(&fib_info_lock); 1245 old_info_hash = fib_info_hash; 1246 old_laddrhash = fib_info_laddrhash; 1247 fib_info_hash_size = new_size; 1248 1249 for (i = 0; i < old_size; i++) { 1250 struct hlist_head *head = &fib_info_hash[i]; 1251 struct hlist_node *n; 1252 struct fib_info *fi; 1253 1254 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1255 struct hlist_head *dest; 1256 unsigned int new_hash; 1257 1258 new_hash = fib_info_hashfn(fi); 1259 dest = &new_info_hash[new_hash]; 1260 hlist_add_head(&fi->fib_hash, dest); 1261 } 1262 } 1263 fib_info_hash = new_info_hash; 1264 1265 for (i = 0; i < old_size; i++) { 1266 struct hlist_head *lhead = &fib_info_laddrhash[i]; 1267 struct hlist_node *n; 1268 struct fib_info *fi; 1269 1270 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1271 struct hlist_head *ldest; 1272 unsigned int new_hash; 1273 1274 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 1275 ldest = &new_laddrhash[new_hash]; 1276 hlist_add_head(&fi->fib_lhash, ldest); 1277 } 1278 } 1279 fib_info_laddrhash = new_laddrhash; 1280 1281 spin_unlock_bh(&fib_info_lock); 1282 1283 bytes = old_size * sizeof(struct hlist_head *); 1284 fib_info_hash_free(old_info_hash, bytes); 1285 fib_info_hash_free(old_laddrhash, bytes); 1286 } 1287 1288 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1289 unsigned char scope) 1290 { 1291 struct fib_nh *nh; 1292 1293 if (nhc->nhc_family != AF_INET) 1294 return inet_select_addr(nhc->nhc_dev, 0, scope); 1295 1296 nh = container_of(nhc, struct fib_nh, nh_common); 1297 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1298 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1299 1300 return nh->nh_saddr; 1301 } 1302 1303 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1304 { 1305 struct fib_nh_common *nhc = res->nhc; 1306 1307 if (res->fi->fib_prefsrc) 1308 return res->fi->fib_prefsrc; 1309 1310 if (nhc->nhc_family == AF_INET) { 1311 struct fib_nh *nh; 1312 1313 nh = container_of(nhc, struct fib_nh, nh_common); 1314 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1315 return nh->nh_saddr; 1316 } 1317 1318 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1319 } 1320 1321 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1322 { 1323 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1324 fib_prefsrc != cfg->fc_dst) { 1325 u32 tb_id = cfg->fc_table; 1326 int rc; 1327 1328 if (tb_id == RT_TABLE_MAIN) 1329 tb_id = RT_TABLE_LOCAL; 1330 1331 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1332 fib_prefsrc, tb_id); 1333 1334 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1335 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1336 fib_prefsrc, RT_TABLE_LOCAL); 1337 } 1338 1339 if (rc != RTN_LOCAL) 1340 return false; 1341 } 1342 return true; 1343 } 1344 1345 struct fib_info *fib_create_info(struct fib_config *cfg, 1346 struct netlink_ext_ack *extack) 1347 { 1348 int err; 1349 struct fib_info *fi = NULL; 1350 struct nexthop *nh = NULL; 1351 struct fib_info *ofi; 1352 int nhs = 1; 1353 struct net *net = cfg->fc_nlinfo.nl_net; 1354 1355 if (cfg->fc_type > RTN_MAX) 1356 goto err_inval; 1357 1358 /* Fast check to catch the most weird cases */ 1359 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1360 NL_SET_ERR_MSG(extack, "Invalid scope"); 1361 goto err_inval; 1362 } 1363 1364 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1365 NL_SET_ERR_MSG(extack, 1366 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1367 goto err_inval; 1368 } 1369 1370 if (cfg->fc_nh_id) { 1371 if (!cfg->fc_mx) { 1372 fi = fib_find_info_nh(net, cfg); 1373 if (fi) { 1374 refcount_inc(&fi->fib_treeref); 1375 return fi; 1376 } 1377 } 1378 1379 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1380 if (!nh) { 1381 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1382 goto err_inval; 1383 } 1384 nhs = 0; 1385 } 1386 1387 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1388 if (cfg->fc_mp) { 1389 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1390 if (nhs == 0) 1391 goto err_inval; 1392 } 1393 #endif 1394 1395 err = -ENOBUFS; 1396 if (fib_info_cnt >= fib_info_hash_size) { 1397 unsigned int new_size = fib_info_hash_size << 1; 1398 struct hlist_head *new_info_hash; 1399 struct hlist_head *new_laddrhash; 1400 unsigned int bytes; 1401 1402 if (!new_size) 1403 new_size = 16; 1404 bytes = new_size * sizeof(struct hlist_head *); 1405 new_info_hash = fib_info_hash_alloc(bytes); 1406 new_laddrhash = fib_info_hash_alloc(bytes); 1407 if (!new_info_hash || !new_laddrhash) { 1408 fib_info_hash_free(new_info_hash, bytes); 1409 fib_info_hash_free(new_laddrhash, bytes); 1410 } else 1411 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1412 1413 if (!fib_info_hash_size) 1414 goto failure; 1415 } 1416 1417 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1418 if (!fi) 1419 goto failure; 1420 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1421 cfg->fc_mx_len, extack); 1422 if (IS_ERR(fi->fib_metrics)) { 1423 err = PTR_ERR(fi->fib_metrics); 1424 kfree(fi); 1425 return ERR_PTR(err); 1426 } 1427 1428 fib_info_cnt++; 1429 fi->fib_net = net; 1430 fi->fib_protocol = cfg->fc_protocol; 1431 fi->fib_scope = cfg->fc_scope; 1432 fi->fib_flags = cfg->fc_flags; 1433 fi->fib_priority = cfg->fc_priority; 1434 fi->fib_prefsrc = cfg->fc_prefsrc; 1435 fi->fib_type = cfg->fc_type; 1436 fi->fib_tb_id = cfg->fc_table; 1437 1438 fi->fib_nhs = nhs; 1439 if (nh) { 1440 if (!nexthop_get(nh)) { 1441 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1442 err = -EINVAL; 1443 } else { 1444 err = 0; 1445 fi->nh = nh; 1446 } 1447 } else { 1448 change_nexthops(fi) { 1449 nexthop_nh->nh_parent = fi; 1450 } endfor_nexthops(fi) 1451 1452 if (cfg->fc_mp) 1453 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1454 extack); 1455 else 1456 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1457 } 1458 1459 if (err != 0) 1460 goto failure; 1461 1462 if (fib_props[cfg->fc_type].error) { 1463 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1464 NL_SET_ERR_MSG(extack, 1465 "Gateway, device and multipath can not be specified for this route type"); 1466 goto err_inval; 1467 } 1468 goto link_it; 1469 } else { 1470 switch (cfg->fc_type) { 1471 case RTN_UNICAST: 1472 case RTN_LOCAL: 1473 case RTN_BROADCAST: 1474 case RTN_ANYCAST: 1475 case RTN_MULTICAST: 1476 break; 1477 default: 1478 NL_SET_ERR_MSG(extack, "Invalid route type"); 1479 goto err_inval; 1480 } 1481 } 1482 1483 if (cfg->fc_scope > RT_SCOPE_HOST) { 1484 NL_SET_ERR_MSG(extack, "Invalid scope"); 1485 goto err_inval; 1486 } 1487 1488 if (fi->nh) { 1489 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1490 if (err) 1491 goto failure; 1492 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1493 struct fib_nh *nh = fi->fib_nh; 1494 1495 /* Local address is added. */ 1496 if (nhs != 1) { 1497 NL_SET_ERR_MSG(extack, 1498 "Route with host scope can not have multiple nexthops"); 1499 goto err_inval; 1500 } 1501 if (nh->fib_nh_gw_family) { 1502 NL_SET_ERR_MSG(extack, 1503 "Route with host scope can not have a gateway"); 1504 goto err_inval; 1505 } 1506 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1507 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1508 err = -ENODEV; 1509 if (!nh->fib_nh_dev) 1510 goto failure; 1511 } else { 1512 int linkdown = 0; 1513 1514 change_nexthops(fi) { 1515 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1516 cfg->fc_table, cfg->fc_scope, 1517 extack); 1518 if (err != 0) 1519 goto failure; 1520 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1521 linkdown++; 1522 } endfor_nexthops(fi) 1523 if (linkdown == fi->fib_nhs) 1524 fi->fib_flags |= RTNH_F_LINKDOWN; 1525 } 1526 1527 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1528 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1529 goto err_inval; 1530 } 1531 1532 if (!fi->nh) { 1533 change_nexthops(fi) { 1534 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1535 fi->fib_scope); 1536 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1537 fi->fib_nh_is_v6 = true; 1538 } endfor_nexthops(fi) 1539 1540 fib_rebalance(fi); 1541 } 1542 1543 link_it: 1544 ofi = fib_find_info(fi); 1545 if (ofi) { 1546 fi->fib_dead = 1; 1547 free_fib_info(fi); 1548 refcount_inc(&ofi->fib_treeref); 1549 return ofi; 1550 } 1551 1552 refcount_set(&fi->fib_treeref, 1); 1553 refcount_set(&fi->fib_clntref, 1); 1554 spin_lock_bh(&fib_info_lock); 1555 hlist_add_head(&fi->fib_hash, 1556 &fib_info_hash[fib_info_hashfn(fi)]); 1557 if (fi->fib_prefsrc) { 1558 struct hlist_head *head; 1559 1560 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1561 hlist_add_head(&fi->fib_lhash, head); 1562 } 1563 if (fi->nh) { 1564 list_add(&fi->nh_list, &nh->fi_list); 1565 } else { 1566 change_nexthops(fi) { 1567 struct hlist_head *head; 1568 unsigned int hash; 1569 1570 if (!nexthop_nh->fib_nh_dev) 1571 continue; 1572 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex); 1573 head = &fib_info_devhash[hash]; 1574 hlist_add_head(&nexthop_nh->nh_hash, head); 1575 } endfor_nexthops(fi) 1576 } 1577 spin_unlock_bh(&fib_info_lock); 1578 return fi; 1579 1580 err_inval: 1581 err = -EINVAL; 1582 1583 failure: 1584 if (fi) { 1585 fi->fib_dead = 1; 1586 free_fib_info(fi); 1587 } 1588 1589 return ERR_PTR(err); 1590 } 1591 1592 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1593 u8 rt_family, unsigned char *flags, bool skip_oif) 1594 { 1595 if (nhc->nhc_flags & RTNH_F_DEAD) 1596 *flags |= RTNH_F_DEAD; 1597 1598 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1599 *flags |= RTNH_F_LINKDOWN; 1600 1601 rcu_read_lock(); 1602 switch (nhc->nhc_family) { 1603 case AF_INET: 1604 if (ip_ignore_linkdown(nhc->nhc_dev)) 1605 *flags |= RTNH_F_DEAD; 1606 break; 1607 case AF_INET6: 1608 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1609 *flags |= RTNH_F_DEAD; 1610 break; 1611 } 1612 rcu_read_unlock(); 1613 } 1614 1615 switch (nhc->nhc_gw_family) { 1616 case AF_INET: 1617 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1618 goto nla_put_failure; 1619 break; 1620 case AF_INET6: 1621 /* if gateway family does not match nexthop family 1622 * gateway is encoded as RTA_VIA 1623 */ 1624 if (rt_family != nhc->nhc_gw_family) { 1625 int alen = sizeof(struct in6_addr); 1626 struct nlattr *nla; 1627 struct rtvia *via; 1628 1629 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1630 if (!nla) 1631 goto nla_put_failure; 1632 1633 via = nla_data(nla); 1634 via->rtvia_family = AF_INET6; 1635 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1636 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1637 &nhc->nhc_gw.ipv6) < 0) { 1638 goto nla_put_failure; 1639 } 1640 break; 1641 } 1642 1643 *flags |= (nhc->nhc_flags & 1644 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1645 1646 if (!skip_oif && nhc->nhc_dev && 1647 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1648 goto nla_put_failure; 1649 1650 if (nhc->nhc_lwtstate && 1651 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1652 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1653 goto nla_put_failure; 1654 1655 return 0; 1656 1657 nla_put_failure: 1658 return -EMSGSIZE; 1659 } 1660 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1661 1662 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1663 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1664 int nh_weight, u8 rt_family, u32 nh_tclassid) 1665 { 1666 const struct net_device *dev = nhc->nhc_dev; 1667 struct rtnexthop *rtnh; 1668 unsigned char flags = 0; 1669 1670 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1671 if (!rtnh) 1672 goto nla_put_failure; 1673 1674 rtnh->rtnh_hops = nh_weight - 1; 1675 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1676 1677 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1678 goto nla_put_failure; 1679 1680 rtnh->rtnh_flags = flags; 1681 1682 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1683 goto nla_put_failure; 1684 1685 /* length of rtnetlink header + attributes */ 1686 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1687 1688 return 0; 1689 1690 nla_put_failure: 1691 return -EMSGSIZE; 1692 } 1693 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1694 #endif 1695 1696 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1697 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1698 { 1699 struct nlattr *mp; 1700 1701 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1702 if (!mp) 1703 goto nla_put_failure; 1704 1705 if (unlikely(fi->nh)) { 1706 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1707 goto nla_put_failure; 1708 goto mp_end; 1709 } 1710 1711 for_nexthops(fi) { 1712 u32 nh_tclassid = 0; 1713 #ifdef CONFIG_IP_ROUTE_CLASSID 1714 nh_tclassid = nh->nh_tclassid; 1715 #endif 1716 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1717 AF_INET, nh_tclassid) < 0) 1718 goto nla_put_failure; 1719 } endfor_nexthops(fi); 1720 1721 mp_end: 1722 nla_nest_end(skb, mp); 1723 1724 return 0; 1725 1726 nla_put_failure: 1727 return -EMSGSIZE; 1728 } 1729 #else 1730 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1731 { 1732 return 0; 1733 } 1734 #endif 1735 1736 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1737 const struct fib_rt_info *fri, unsigned int flags) 1738 { 1739 unsigned int nhs = fib_info_num_path(fri->fi); 1740 struct fib_info *fi = fri->fi; 1741 u32 tb_id = fri->tb_id; 1742 struct nlmsghdr *nlh; 1743 struct rtmsg *rtm; 1744 1745 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1746 if (!nlh) 1747 return -EMSGSIZE; 1748 1749 rtm = nlmsg_data(nlh); 1750 rtm->rtm_family = AF_INET; 1751 rtm->rtm_dst_len = fri->dst_len; 1752 rtm->rtm_src_len = 0; 1753 rtm->rtm_tos = fri->tos; 1754 if (tb_id < 256) 1755 rtm->rtm_table = tb_id; 1756 else 1757 rtm->rtm_table = RT_TABLE_COMPAT; 1758 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1759 goto nla_put_failure; 1760 rtm->rtm_type = fri->type; 1761 rtm->rtm_flags = fi->fib_flags; 1762 rtm->rtm_scope = fi->fib_scope; 1763 rtm->rtm_protocol = fi->fib_protocol; 1764 1765 if (rtm->rtm_dst_len && 1766 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1767 goto nla_put_failure; 1768 if (fi->fib_priority && 1769 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1770 goto nla_put_failure; 1771 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1772 goto nla_put_failure; 1773 1774 if (fi->fib_prefsrc && 1775 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1776 goto nla_put_failure; 1777 1778 if (fi->nh) { 1779 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1780 goto nla_put_failure; 1781 if (nexthop_is_blackhole(fi->nh)) 1782 rtm->rtm_type = RTN_BLACKHOLE; 1783 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode) 1784 goto offload; 1785 } 1786 1787 if (nhs == 1) { 1788 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1789 unsigned char flags = 0; 1790 1791 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1792 goto nla_put_failure; 1793 1794 rtm->rtm_flags = flags; 1795 #ifdef CONFIG_IP_ROUTE_CLASSID 1796 if (nhc->nhc_family == AF_INET) { 1797 struct fib_nh *nh; 1798 1799 nh = container_of(nhc, struct fib_nh, nh_common); 1800 if (nh->nh_tclassid && 1801 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1802 goto nla_put_failure; 1803 } 1804 #endif 1805 } else { 1806 if (fib_add_multipath(skb, fi) < 0) 1807 goto nla_put_failure; 1808 } 1809 1810 offload: 1811 if (fri->offload) 1812 rtm->rtm_flags |= RTM_F_OFFLOAD; 1813 if (fri->trap) 1814 rtm->rtm_flags |= RTM_F_TRAP; 1815 if (fri->offload_failed) 1816 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1817 1818 nlmsg_end(skb, nlh); 1819 return 0; 1820 1821 nla_put_failure: 1822 nlmsg_cancel(skb, nlh); 1823 return -EMSGSIZE; 1824 } 1825 1826 /* 1827 * Update FIB if: 1828 * - local address disappeared -> we must delete all the entries 1829 * referring to it. 1830 * - device went down -> we must shutdown all nexthops going via it. 1831 */ 1832 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1833 { 1834 int ret = 0; 1835 unsigned int hash = fib_laddr_hashfn(local); 1836 struct hlist_head *head = &fib_info_laddrhash[hash]; 1837 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1838 struct net *net = dev_net(dev); 1839 struct fib_info *fi; 1840 1841 if (!fib_info_laddrhash || local == 0) 1842 return 0; 1843 1844 hlist_for_each_entry(fi, head, fib_lhash) { 1845 if (!net_eq(fi->fib_net, net) || 1846 fi->fib_tb_id != tb_id) 1847 continue; 1848 if (fi->fib_prefsrc == local) { 1849 fi->fib_flags |= RTNH_F_DEAD; 1850 ret++; 1851 } 1852 } 1853 return ret; 1854 } 1855 1856 static int call_fib_nh_notifiers(struct fib_nh *nh, 1857 enum fib_event_type event_type) 1858 { 1859 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1860 struct fib_nh_notifier_info info = { 1861 .fib_nh = nh, 1862 }; 1863 1864 switch (event_type) { 1865 case FIB_EVENT_NH_ADD: 1866 if (nh->fib_nh_flags & RTNH_F_DEAD) 1867 break; 1868 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1869 break; 1870 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1871 &info.info); 1872 case FIB_EVENT_NH_DEL: 1873 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1874 (nh->fib_nh_flags & RTNH_F_DEAD)) 1875 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1876 event_type, &info.info); 1877 break; 1878 default: 1879 break; 1880 } 1881 1882 return NOTIFY_DONE; 1883 } 1884 1885 /* Update the PMTU of exceptions when: 1886 * - the new MTU of the first hop becomes smaller than the PMTU 1887 * - the old MTU was the same as the PMTU, and it limited discovery of 1888 * larger MTUs on the path. With that limit raised, we can now 1889 * discover larger MTUs 1890 * A special case is locked exceptions, for which the PMTU is smaller 1891 * than the minimal accepted PMTU: 1892 * - if the new MTU is greater than the PMTU, don't make any change 1893 * - otherwise, unlock and set PMTU 1894 */ 1895 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1896 { 1897 struct fnhe_hash_bucket *bucket; 1898 int i; 1899 1900 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1901 if (!bucket) 1902 return; 1903 1904 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1905 struct fib_nh_exception *fnhe; 1906 1907 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1908 fnhe; 1909 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1910 if (fnhe->fnhe_mtu_locked) { 1911 if (new <= fnhe->fnhe_pmtu) { 1912 fnhe->fnhe_pmtu = new; 1913 fnhe->fnhe_mtu_locked = false; 1914 } 1915 } else if (new < fnhe->fnhe_pmtu || 1916 orig == fnhe->fnhe_pmtu) { 1917 fnhe->fnhe_pmtu = new; 1918 } 1919 } 1920 } 1921 } 1922 1923 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1924 { 1925 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1926 struct hlist_head *head = &fib_info_devhash[hash]; 1927 struct fib_nh *nh; 1928 1929 hlist_for_each_entry(nh, head, nh_hash) { 1930 if (nh->fib_nh_dev == dev) 1931 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1932 } 1933 } 1934 1935 /* Event force Flags Description 1936 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1937 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1938 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1939 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1940 * 1941 * only used when fib_nh is built into fib_info 1942 */ 1943 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1944 { 1945 int ret = 0; 1946 int scope = RT_SCOPE_NOWHERE; 1947 struct fib_info *prev_fi = NULL; 1948 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1949 struct hlist_head *head = &fib_info_devhash[hash]; 1950 struct fib_nh *nh; 1951 1952 if (force) 1953 scope = -1; 1954 1955 hlist_for_each_entry(nh, head, nh_hash) { 1956 struct fib_info *fi = nh->nh_parent; 1957 int dead; 1958 1959 BUG_ON(!fi->fib_nhs); 1960 if (nh->fib_nh_dev != dev || fi == prev_fi) 1961 continue; 1962 prev_fi = fi; 1963 dead = 0; 1964 change_nexthops(fi) { 1965 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1966 dead++; 1967 else if (nexthop_nh->fib_nh_dev == dev && 1968 nexthop_nh->fib_nh_scope != scope) { 1969 switch (event) { 1970 case NETDEV_DOWN: 1971 case NETDEV_UNREGISTER: 1972 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 1973 fallthrough; 1974 case NETDEV_CHANGE: 1975 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1976 break; 1977 } 1978 call_fib_nh_notifiers(nexthop_nh, 1979 FIB_EVENT_NH_DEL); 1980 dead++; 1981 } 1982 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1983 if (event == NETDEV_UNREGISTER && 1984 nexthop_nh->fib_nh_dev == dev) { 1985 dead = fi->fib_nhs; 1986 break; 1987 } 1988 #endif 1989 } endfor_nexthops(fi) 1990 if (dead == fi->fib_nhs) { 1991 switch (event) { 1992 case NETDEV_DOWN: 1993 case NETDEV_UNREGISTER: 1994 fi->fib_flags |= RTNH_F_DEAD; 1995 fallthrough; 1996 case NETDEV_CHANGE: 1997 fi->fib_flags |= RTNH_F_LINKDOWN; 1998 break; 1999 } 2000 ret++; 2001 } 2002 2003 fib_rebalance(fi); 2004 } 2005 2006 return ret; 2007 } 2008 2009 /* Must be invoked inside of an RCU protected region. */ 2010 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2011 { 2012 struct fib_info *fi = NULL, *last_resort = NULL; 2013 struct hlist_head *fa_head = res->fa_head; 2014 struct fib_table *tb = res->table; 2015 u8 slen = 32 - res->prefixlen; 2016 int order = -1, last_idx = -1; 2017 struct fib_alias *fa, *fa1 = NULL; 2018 u32 last_prio = res->fi->fib_priority; 2019 u8 last_tos = 0; 2020 2021 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2022 struct fib_info *next_fi = fa->fa_info; 2023 struct fib_nh_common *nhc; 2024 2025 if (fa->fa_slen != slen) 2026 continue; 2027 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 2028 continue; 2029 if (fa->tb_id != tb->tb_id) 2030 continue; 2031 if (next_fi->fib_priority > last_prio && 2032 fa->fa_tos == last_tos) { 2033 if (last_tos) 2034 continue; 2035 break; 2036 } 2037 if (next_fi->fib_flags & RTNH_F_DEAD) 2038 continue; 2039 last_tos = fa->fa_tos; 2040 last_prio = next_fi->fib_priority; 2041 2042 if (next_fi->fib_scope != res->scope || 2043 fa->fa_type != RTN_UNICAST) 2044 continue; 2045 2046 nhc = fib_info_nhc(next_fi, 0); 2047 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2048 continue; 2049 2050 fib_alias_accessed(fa); 2051 2052 if (!fi) { 2053 if (next_fi != res->fi) 2054 break; 2055 fa1 = fa; 2056 } else if (!fib_detect_death(fi, order, &last_resort, 2057 &last_idx, fa1->fa_default)) { 2058 fib_result_assign(res, fi); 2059 fa1->fa_default = order; 2060 goto out; 2061 } 2062 fi = next_fi; 2063 order++; 2064 } 2065 2066 if (order <= 0 || !fi) { 2067 if (fa1) 2068 fa1->fa_default = -1; 2069 goto out; 2070 } 2071 2072 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2073 fa1->fa_default)) { 2074 fib_result_assign(res, fi); 2075 fa1->fa_default = order; 2076 goto out; 2077 } 2078 2079 if (last_idx >= 0) 2080 fib_result_assign(res, last_resort); 2081 fa1->fa_default = last_idx; 2082 out: 2083 return; 2084 } 2085 2086 /* 2087 * Dead device goes up. We wake up dead nexthops. 2088 * It takes sense only on multipath routes. 2089 * 2090 * only used when fib_nh is built into fib_info 2091 */ 2092 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2093 { 2094 struct fib_info *prev_fi; 2095 unsigned int hash; 2096 struct hlist_head *head; 2097 struct fib_nh *nh; 2098 int ret; 2099 2100 if (!(dev->flags & IFF_UP)) 2101 return 0; 2102 2103 if (nh_flags & RTNH_F_DEAD) { 2104 unsigned int flags = dev_get_flags(dev); 2105 2106 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2107 nh_flags |= RTNH_F_LINKDOWN; 2108 } 2109 2110 prev_fi = NULL; 2111 hash = fib_devindex_hashfn(dev->ifindex); 2112 head = &fib_info_devhash[hash]; 2113 ret = 0; 2114 2115 hlist_for_each_entry(nh, head, nh_hash) { 2116 struct fib_info *fi = nh->nh_parent; 2117 int alive; 2118 2119 BUG_ON(!fi->fib_nhs); 2120 if (nh->fib_nh_dev != dev || fi == prev_fi) 2121 continue; 2122 2123 prev_fi = fi; 2124 alive = 0; 2125 change_nexthops(fi) { 2126 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2127 alive++; 2128 continue; 2129 } 2130 if (!nexthop_nh->fib_nh_dev || 2131 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2132 continue; 2133 if (nexthop_nh->fib_nh_dev != dev || 2134 !__in_dev_get_rtnl(dev)) 2135 continue; 2136 alive++; 2137 nexthop_nh->fib_nh_flags &= ~nh_flags; 2138 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2139 } endfor_nexthops(fi) 2140 2141 if (alive > 0) { 2142 fi->fib_flags &= ~nh_flags; 2143 ret++; 2144 } 2145 2146 fib_rebalance(fi); 2147 } 2148 2149 return ret; 2150 } 2151 2152 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2153 static bool fib_good_nh(const struct fib_nh *nh) 2154 { 2155 int state = NUD_REACHABLE; 2156 2157 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2158 struct neighbour *n; 2159 2160 rcu_read_lock_bh(); 2161 2162 if (likely(nh->fib_nh_gw_family == AF_INET)) 2163 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2164 (__force u32)nh->fib_nh_gw4); 2165 else if (nh->fib_nh_gw_family == AF_INET6) 2166 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2167 &nh->fib_nh_gw6); 2168 else 2169 n = NULL; 2170 if (n) 2171 state = n->nud_state; 2172 2173 rcu_read_unlock_bh(); 2174 } 2175 2176 return !!(state & NUD_VALID); 2177 } 2178 2179 void fib_select_multipath(struct fib_result *res, int hash) 2180 { 2181 struct fib_info *fi = res->fi; 2182 struct net *net = fi->fib_net; 2183 bool first = false; 2184 2185 if (unlikely(res->fi->nh)) { 2186 nexthop_path_fib_result(res, hash); 2187 return; 2188 } 2189 2190 change_nexthops(fi) { 2191 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 2192 if (!fib_good_nh(nexthop_nh)) 2193 continue; 2194 if (!first) { 2195 res->nh_sel = nhsel; 2196 res->nhc = &nexthop_nh->nh_common; 2197 first = true; 2198 } 2199 } 2200 2201 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2202 continue; 2203 2204 res->nh_sel = nhsel; 2205 res->nhc = &nexthop_nh->nh_common; 2206 return; 2207 } endfor_nexthops(fi); 2208 } 2209 #endif 2210 2211 void fib_select_path(struct net *net, struct fib_result *res, 2212 struct flowi4 *fl4, const struct sk_buff *skb) 2213 { 2214 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 2215 goto check_saddr; 2216 2217 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2218 if (fib_info_num_path(res->fi) > 1) { 2219 int h = fib_multipath_hash(net, fl4, skb, NULL); 2220 2221 fib_select_multipath(res, h); 2222 } 2223 else 2224 #endif 2225 if (!res->prefixlen && 2226 res->table->tb_num_default > 1 && 2227 res->type == RTN_UNICAST) 2228 fib_select_default(fl4, res); 2229 2230 check_saddr: 2231 if (!fl4->saddr) 2232 fl4->saddr = fib_result_prefsrc(net, res); 2233 } 2234