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 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 666 struct netlink_ext_ack *extack) 667 { 668 if (nla_len(nla) < sizeof(*gw)) { 669 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 670 return -EINVAL; 671 } 672 673 *gw = nla_get_in_addr(nla); 674 675 return 0; 676 } 677 678 /* only called when fib_nh is integrated into fib_info */ 679 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 680 int remaining, struct fib_config *cfg, 681 struct netlink_ext_ack *extack) 682 { 683 struct net *net = fi->fib_net; 684 struct fib_config fib_cfg; 685 struct fib_nh *nh; 686 int ret; 687 688 change_nexthops(fi) { 689 int attrlen; 690 691 memset(&fib_cfg, 0, sizeof(fib_cfg)); 692 693 if (!rtnh_ok(rtnh, remaining)) { 694 NL_SET_ERR_MSG(extack, 695 "Invalid nexthop configuration - extra data after nexthop"); 696 return -EINVAL; 697 } 698 699 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 700 NL_SET_ERR_MSG(extack, 701 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 702 return -EINVAL; 703 } 704 705 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 706 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 707 708 attrlen = rtnh_attrlen(rtnh); 709 if (attrlen > 0) { 710 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 711 712 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 713 nlav = nla_find(attrs, attrlen, RTA_VIA); 714 if (nla && nlav) { 715 NL_SET_ERR_MSG(extack, 716 "Nexthop configuration can not contain both GATEWAY and VIA"); 717 return -EINVAL; 718 } 719 if (nla) { 720 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 721 extack); 722 if (ret) 723 goto errout; 724 725 if (fib_cfg.fc_gw4) 726 fib_cfg.fc_gw_family = AF_INET; 727 } else if (nlav) { 728 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 729 if (ret) 730 goto errout; 731 } 732 733 nla = nla_find(attrs, attrlen, RTA_FLOW); 734 if (nla) { 735 if (nla_len(nla) < sizeof(u32)) { 736 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 737 return -EINVAL; 738 } 739 fib_cfg.fc_flow = nla_get_u32(nla); 740 } 741 742 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 743 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 744 if (nla) 745 fib_cfg.fc_encap_type = nla_get_u16(nla); 746 } 747 748 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 749 rtnh->rtnh_hops + 1, extack); 750 if (ret) 751 goto errout; 752 753 rtnh = rtnh_next(rtnh, &remaining); 754 } endfor_nexthops(fi); 755 756 ret = -EINVAL; 757 nh = fib_info_nh(fi, 0); 758 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 759 NL_SET_ERR_MSG(extack, 760 "Nexthop device index does not match RTA_OIF"); 761 goto errout; 762 } 763 if (cfg->fc_gw_family) { 764 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 765 (cfg->fc_gw_family == AF_INET && 766 nh->fib_nh_gw4 != cfg->fc_gw4) || 767 (cfg->fc_gw_family == AF_INET6 && 768 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 769 NL_SET_ERR_MSG(extack, 770 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 771 goto errout; 772 } 773 } 774 #ifdef CONFIG_IP_ROUTE_CLASSID 775 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 776 NL_SET_ERR_MSG(extack, 777 "Nexthop class id does not match RTA_FLOW"); 778 goto errout; 779 } 780 #endif 781 ret = 0; 782 errout: 783 return ret; 784 } 785 786 /* only called when fib_nh is integrated into fib_info */ 787 static void fib_rebalance(struct fib_info *fi) 788 { 789 int total; 790 int w; 791 792 if (fib_info_num_path(fi) < 2) 793 return; 794 795 total = 0; 796 for_nexthops(fi) { 797 if (nh->fib_nh_flags & RTNH_F_DEAD) 798 continue; 799 800 if (ip_ignore_linkdown(nh->fib_nh_dev) && 801 nh->fib_nh_flags & RTNH_F_LINKDOWN) 802 continue; 803 804 total += nh->fib_nh_weight; 805 } endfor_nexthops(fi); 806 807 w = 0; 808 change_nexthops(fi) { 809 int upper_bound; 810 811 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 812 upper_bound = -1; 813 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 814 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 815 upper_bound = -1; 816 } else { 817 w += nexthop_nh->fib_nh_weight; 818 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 819 total) - 1; 820 } 821 822 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 823 } endfor_nexthops(fi); 824 } 825 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 826 827 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 828 int remaining, struct fib_config *cfg, 829 struct netlink_ext_ack *extack) 830 { 831 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 832 833 return -EINVAL; 834 } 835 836 #define fib_rebalance(fi) do { } while (0) 837 838 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 839 840 static int fib_encap_match(struct net *net, u16 encap_type, 841 struct nlattr *encap, 842 const struct fib_nh *nh, 843 const struct fib_config *cfg, 844 struct netlink_ext_ack *extack) 845 { 846 struct lwtunnel_state *lwtstate; 847 int ret, result = 0; 848 849 if (encap_type == LWTUNNEL_ENCAP_NONE) 850 return 0; 851 852 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 853 cfg, &lwtstate, extack); 854 if (!ret) { 855 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 856 lwtstate_free(lwtstate); 857 } 858 859 return result; 860 } 861 862 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 863 struct netlink_ext_ack *extack) 864 { 865 #ifdef CONFIG_IP_ROUTE_MULTIPATH 866 struct rtnexthop *rtnh; 867 int remaining; 868 #endif 869 870 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 871 return 1; 872 873 if (cfg->fc_nh_id) { 874 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 875 return 0; 876 return 1; 877 } 878 879 if (cfg->fc_oif || cfg->fc_gw_family) { 880 struct fib_nh *nh = fib_info_nh(fi, 0); 881 882 if (cfg->fc_encap) { 883 if (fib_encap_match(net, cfg->fc_encap_type, 884 cfg->fc_encap, nh, cfg, extack)) 885 return 1; 886 } 887 #ifdef CONFIG_IP_ROUTE_CLASSID 888 if (cfg->fc_flow && 889 cfg->fc_flow != nh->nh_tclassid) 890 return 1; 891 #endif 892 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 893 (cfg->fc_gw_family && 894 cfg->fc_gw_family != nh->fib_nh_gw_family)) 895 return 1; 896 897 if (cfg->fc_gw_family == AF_INET && 898 cfg->fc_gw4 != nh->fib_nh_gw4) 899 return 1; 900 901 if (cfg->fc_gw_family == AF_INET6 && 902 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 903 return 1; 904 905 return 0; 906 } 907 908 #ifdef CONFIG_IP_ROUTE_MULTIPATH 909 if (!cfg->fc_mp) 910 return 0; 911 912 rtnh = cfg->fc_mp; 913 remaining = cfg->fc_mp_len; 914 915 for_nexthops(fi) { 916 int attrlen; 917 918 if (!rtnh_ok(rtnh, remaining)) 919 return -EINVAL; 920 921 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 922 return 1; 923 924 attrlen = rtnh_attrlen(rtnh); 925 if (attrlen > 0) { 926 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 927 int err; 928 929 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 930 nlav = nla_find(attrs, attrlen, RTA_VIA); 931 if (nla && nlav) { 932 NL_SET_ERR_MSG(extack, 933 "Nexthop configuration can not contain both GATEWAY and VIA"); 934 return -EINVAL; 935 } 936 937 if (nla) { 938 __be32 gw; 939 940 err = fib_gw_from_attr(&gw, nla, extack); 941 if (err) 942 return err; 943 944 if (nh->fib_nh_gw_family != AF_INET || 945 gw != nh->fib_nh_gw4) 946 return 1; 947 } else if (nlav) { 948 struct fib_config cfg2; 949 950 err = fib_gw_from_via(&cfg2, nlav, extack); 951 if (err) 952 return err; 953 954 switch (nh->fib_nh_gw_family) { 955 case AF_INET: 956 if (cfg2.fc_gw_family != AF_INET || 957 cfg2.fc_gw4 != nh->fib_nh_gw4) 958 return 1; 959 break; 960 case AF_INET6: 961 if (cfg2.fc_gw_family != AF_INET6 || 962 ipv6_addr_cmp(&cfg2.fc_gw6, 963 &nh->fib_nh_gw6)) 964 return 1; 965 break; 966 } 967 } 968 969 #ifdef CONFIG_IP_ROUTE_CLASSID 970 nla = nla_find(attrs, attrlen, RTA_FLOW); 971 if (nla) { 972 if (nla_len(nla) < sizeof(u32)) { 973 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 974 return -EINVAL; 975 } 976 if (nla_get_u32(nla) != nh->nh_tclassid) 977 return 1; 978 } 979 #endif 980 } 981 982 rtnh = rtnh_next(rtnh, &remaining); 983 } endfor_nexthops(fi); 984 #endif 985 return 0; 986 } 987 988 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 989 { 990 struct nlattr *nla; 991 int remaining; 992 993 if (!cfg->fc_mx) 994 return true; 995 996 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 997 int type = nla_type(nla); 998 u32 fi_val, val; 999 1000 if (!type) 1001 continue; 1002 if (type > RTAX_MAX) 1003 return false; 1004 1005 if (type == RTAX_CC_ALGO) { 1006 char tmp[TCP_CA_NAME_MAX]; 1007 bool ecn_ca = false; 1008 1009 nla_strscpy(tmp, nla, sizeof(tmp)); 1010 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1011 } else { 1012 if (nla_len(nla) != sizeof(u32)) 1013 return false; 1014 val = nla_get_u32(nla); 1015 } 1016 1017 fi_val = fi->fib_metrics->metrics[type - 1]; 1018 if (type == RTAX_FEATURES) 1019 fi_val &= ~DST_FEATURE_ECN_CA; 1020 1021 if (fi_val != val) 1022 return false; 1023 } 1024 1025 return true; 1026 } 1027 1028 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1029 u32 table, struct netlink_ext_ack *extack) 1030 { 1031 struct fib6_config cfg = { 1032 .fc_table = table, 1033 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1034 .fc_ifindex = nh->fib_nh_oif, 1035 .fc_gateway = nh->fib_nh_gw6, 1036 }; 1037 struct fib6_nh fib6_nh = {}; 1038 int err; 1039 1040 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1041 if (!err) { 1042 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1043 dev_hold(nh->fib_nh_dev); 1044 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1045 nh->fib_nh_scope = RT_SCOPE_LINK; 1046 1047 ipv6_stub->fib6_nh_release(&fib6_nh); 1048 } 1049 1050 return err; 1051 } 1052 1053 /* 1054 * Picture 1055 * ------- 1056 * 1057 * Semantics of nexthop is very messy by historical reasons. 1058 * We have to take into account, that: 1059 * a) gateway can be actually local interface address, 1060 * so that gatewayed route is direct. 1061 * b) gateway must be on-link address, possibly 1062 * described not by an ifaddr, but also by a direct route. 1063 * c) If both gateway and interface are specified, they should not 1064 * contradict. 1065 * d) If we use tunnel routes, gateway could be not on-link. 1066 * 1067 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1068 * results in pretty ugly and hairy code with obscure logic. 1069 * 1070 * I chose to generalized it instead, so that the size 1071 * of code does not increase practically, but it becomes 1072 * much more general. 1073 * Every prefix is assigned a "scope" value: "host" is local address, 1074 * "link" is direct route, 1075 * [ ... "site" ... "interior" ... ] 1076 * and "universe" is true gateway route with global meaning. 1077 * 1078 * Every prefix refers to a set of "nexthop"s (gw, oif), 1079 * where gw must have narrower scope. This recursion stops 1080 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1081 * which means that gw is forced to be on link. 1082 * 1083 * Code is still hairy, but now it is apparently logically 1084 * consistent and very flexible. F.e. as by-product it allows 1085 * to co-exists in peace independent exterior and interior 1086 * routing processes. 1087 * 1088 * Normally it looks as following. 1089 * 1090 * {universe prefix} -> (gw, oif) [scope link] 1091 * | 1092 * |-> {link prefix} -> (gw, oif) [scope local] 1093 * | 1094 * |-> {local prefix} (terminal node) 1095 */ 1096 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1097 u8 scope, struct netlink_ext_ack *extack) 1098 { 1099 struct net_device *dev; 1100 struct fib_result res; 1101 int err = 0; 1102 1103 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1104 unsigned int addr_type; 1105 1106 if (scope >= RT_SCOPE_LINK) { 1107 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1108 return -EINVAL; 1109 } 1110 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1111 if (!dev) { 1112 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1113 return -ENODEV; 1114 } 1115 if (!(dev->flags & IFF_UP)) { 1116 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1117 return -ENETDOWN; 1118 } 1119 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1120 if (addr_type != RTN_UNICAST) { 1121 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1122 return -EINVAL; 1123 } 1124 if (!netif_carrier_ok(dev)) 1125 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1126 nh->fib_nh_dev = dev; 1127 dev_hold(dev); 1128 nh->fib_nh_scope = RT_SCOPE_LINK; 1129 return 0; 1130 } 1131 rcu_read_lock(); 1132 { 1133 struct fib_table *tbl = NULL; 1134 struct flowi4 fl4 = { 1135 .daddr = nh->fib_nh_gw4, 1136 .flowi4_scope = scope + 1, 1137 .flowi4_oif = nh->fib_nh_oif, 1138 .flowi4_iif = LOOPBACK_IFINDEX, 1139 }; 1140 1141 /* It is not necessary, but requires a bit of thinking */ 1142 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1143 fl4.flowi4_scope = RT_SCOPE_LINK; 1144 1145 if (table && table != RT_TABLE_MAIN) 1146 tbl = fib_get_table(net, table); 1147 1148 if (tbl) 1149 err = fib_table_lookup(tbl, &fl4, &res, 1150 FIB_LOOKUP_IGNORE_LINKSTATE | 1151 FIB_LOOKUP_NOREF); 1152 1153 /* on error or if no table given do full lookup. This 1154 * is needed for example when nexthops are in the local 1155 * table rather than the given table 1156 */ 1157 if (!tbl || err) { 1158 err = fib_lookup(net, &fl4, &res, 1159 FIB_LOOKUP_IGNORE_LINKSTATE); 1160 } 1161 1162 if (err) { 1163 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1164 goto out; 1165 } 1166 } 1167 1168 err = -EINVAL; 1169 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1170 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1171 goto out; 1172 } 1173 nh->fib_nh_scope = res.scope; 1174 nh->fib_nh_oif = FIB_RES_OIF(res); 1175 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1176 if (!dev) { 1177 NL_SET_ERR_MSG(extack, 1178 "No egress device for nexthop gateway"); 1179 goto out; 1180 } 1181 dev_hold(dev); 1182 if (!netif_carrier_ok(dev)) 1183 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1184 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1185 out: 1186 rcu_read_unlock(); 1187 return err; 1188 } 1189 1190 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1191 struct netlink_ext_ack *extack) 1192 { 1193 struct in_device *in_dev; 1194 int err; 1195 1196 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1197 NL_SET_ERR_MSG(extack, 1198 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1199 return -EINVAL; 1200 } 1201 1202 rcu_read_lock(); 1203 1204 err = -ENODEV; 1205 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1206 if (!in_dev) 1207 goto out; 1208 err = -ENETDOWN; 1209 if (!(in_dev->dev->flags & IFF_UP)) { 1210 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1211 goto out; 1212 } 1213 1214 nh->fib_nh_dev = in_dev->dev; 1215 dev_hold(nh->fib_nh_dev); 1216 nh->fib_nh_scope = RT_SCOPE_HOST; 1217 if (!netif_carrier_ok(nh->fib_nh_dev)) 1218 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1219 err = 0; 1220 out: 1221 rcu_read_unlock(); 1222 return err; 1223 } 1224 1225 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1226 struct netlink_ext_ack *extack) 1227 { 1228 int err; 1229 1230 if (nh->fib_nh_gw_family == AF_INET) 1231 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1232 else if (nh->fib_nh_gw_family == AF_INET6) 1233 err = fib_check_nh_v6_gw(net, nh, table, extack); 1234 else 1235 err = fib_check_nh_nongw(net, nh, extack); 1236 1237 return err; 1238 } 1239 1240 static inline unsigned int fib_laddr_hashfn(__be32 val) 1241 { 1242 unsigned int mask = (fib_info_hash_size - 1); 1243 1244 return ((__force u32)val ^ 1245 ((__force u32)val >> 7) ^ 1246 ((__force u32)val >> 14)) & mask; 1247 } 1248 1249 static struct hlist_head *fib_info_hash_alloc(int bytes) 1250 { 1251 if (bytes <= PAGE_SIZE) 1252 return kzalloc(bytes, GFP_KERNEL); 1253 else 1254 return (struct hlist_head *) 1255 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 1256 get_order(bytes)); 1257 } 1258 1259 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 1260 { 1261 if (!hash) 1262 return; 1263 1264 if (bytes <= PAGE_SIZE) 1265 kfree(hash); 1266 else 1267 free_pages((unsigned long) hash, get_order(bytes)); 1268 } 1269 1270 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1271 struct hlist_head *new_laddrhash, 1272 unsigned int new_size) 1273 { 1274 struct hlist_head *old_info_hash, *old_laddrhash; 1275 unsigned int old_size = fib_info_hash_size; 1276 unsigned int i, bytes; 1277 1278 spin_lock_bh(&fib_info_lock); 1279 old_info_hash = fib_info_hash; 1280 old_laddrhash = fib_info_laddrhash; 1281 fib_info_hash_size = new_size; 1282 1283 for (i = 0; i < old_size; i++) { 1284 struct hlist_head *head = &fib_info_hash[i]; 1285 struct hlist_node *n; 1286 struct fib_info *fi; 1287 1288 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1289 struct hlist_head *dest; 1290 unsigned int new_hash; 1291 1292 new_hash = fib_info_hashfn(fi); 1293 dest = &new_info_hash[new_hash]; 1294 hlist_add_head(&fi->fib_hash, dest); 1295 } 1296 } 1297 fib_info_hash = new_info_hash; 1298 1299 for (i = 0; i < old_size; i++) { 1300 struct hlist_head *lhead = &fib_info_laddrhash[i]; 1301 struct hlist_node *n; 1302 struct fib_info *fi; 1303 1304 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1305 struct hlist_head *ldest; 1306 unsigned int new_hash; 1307 1308 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 1309 ldest = &new_laddrhash[new_hash]; 1310 hlist_add_head(&fi->fib_lhash, ldest); 1311 } 1312 } 1313 fib_info_laddrhash = new_laddrhash; 1314 1315 spin_unlock_bh(&fib_info_lock); 1316 1317 bytes = old_size * sizeof(struct hlist_head *); 1318 fib_info_hash_free(old_info_hash, bytes); 1319 fib_info_hash_free(old_laddrhash, bytes); 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 1327 if (nhc->nhc_family != AF_INET) 1328 return inet_select_addr(nhc->nhc_dev, 0, scope); 1329 1330 nh = container_of(nhc, struct fib_nh, nh_common); 1331 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1332 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1333 1334 return nh->nh_saddr; 1335 } 1336 1337 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1338 { 1339 struct fib_nh_common *nhc = res->nhc; 1340 1341 if (res->fi->fib_prefsrc) 1342 return res->fi->fib_prefsrc; 1343 1344 if (nhc->nhc_family == AF_INET) { 1345 struct fib_nh *nh; 1346 1347 nh = container_of(nhc, struct fib_nh, nh_common); 1348 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1349 return nh->nh_saddr; 1350 } 1351 1352 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1353 } 1354 1355 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1356 { 1357 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1358 fib_prefsrc != cfg->fc_dst) { 1359 u32 tb_id = cfg->fc_table; 1360 int rc; 1361 1362 if (tb_id == RT_TABLE_MAIN) 1363 tb_id = RT_TABLE_LOCAL; 1364 1365 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1366 fib_prefsrc, tb_id); 1367 1368 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1369 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1370 fib_prefsrc, RT_TABLE_LOCAL); 1371 } 1372 1373 if (rc != RTN_LOCAL) 1374 return false; 1375 } 1376 return true; 1377 } 1378 1379 struct fib_info *fib_create_info(struct fib_config *cfg, 1380 struct netlink_ext_ack *extack) 1381 { 1382 int err; 1383 struct fib_info *fi = NULL; 1384 struct nexthop *nh = NULL; 1385 struct fib_info *ofi; 1386 int nhs = 1; 1387 struct net *net = cfg->fc_nlinfo.nl_net; 1388 1389 if (cfg->fc_type > RTN_MAX) 1390 goto err_inval; 1391 1392 /* Fast check to catch the most weird cases */ 1393 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1394 NL_SET_ERR_MSG(extack, "Invalid scope"); 1395 goto err_inval; 1396 } 1397 1398 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1399 NL_SET_ERR_MSG(extack, 1400 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1401 goto err_inval; 1402 } 1403 1404 if (cfg->fc_nh_id) { 1405 if (!cfg->fc_mx) { 1406 fi = fib_find_info_nh(net, cfg); 1407 if (fi) { 1408 refcount_inc(&fi->fib_treeref); 1409 return fi; 1410 } 1411 } 1412 1413 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1414 if (!nh) { 1415 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1416 goto err_inval; 1417 } 1418 nhs = 0; 1419 } 1420 1421 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1422 if (cfg->fc_mp) { 1423 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1424 if (nhs == 0) 1425 goto err_inval; 1426 } 1427 #endif 1428 1429 err = -ENOBUFS; 1430 if (fib_info_cnt >= fib_info_hash_size) { 1431 unsigned int new_size = fib_info_hash_size << 1; 1432 struct hlist_head *new_info_hash; 1433 struct hlist_head *new_laddrhash; 1434 unsigned int bytes; 1435 1436 if (!new_size) 1437 new_size = 16; 1438 bytes = new_size * sizeof(struct hlist_head *); 1439 new_info_hash = fib_info_hash_alloc(bytes); 1440 new_laddrhash = fib_info_hash_alloc(bytes); 1441 if (!new_info_hash || !new_laddrhash) { 1442 fib_info_hash_free(new_info_hash, bytes); 1443 fib_info_hash_free(new_laddrhash, bytes); 1444 } else 1445 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1446 1447 if (!fib_info_hash_size) 1448 goto failure; 1449 } 1450 1451 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1452 if (!fi) 1453 goto failure; 1454 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1455 cfg->fc_mx_len, extack); 1456 if (IS_ERR(fi->fib_metrics)) { 1457 err = PTR_ERR(fi->fib_metrics); 1458 kfree(fi); 1459 return ERR_PTR(err); 1460 } 1461 1462 fib_info_cnt++; 1463 fi->fib_net = net; 1464 fi->fib_protocol = cfg->fc_protocol; 1465 fi->fib_scope = cfg->fc_scope; 1466 fi->fib_flags = cfg->fc_flags; 1467 fi->fib_priority = cfg->fc_priority; 1468 fi->fib_prefsrc = cfg->fc_prefsrc; 1469 fi->fib_type = cfg->fc_type; 1470 fi->fib_tb_id = cfg->fc_table; 1471 1472 fi->fib_nhs = nhs; 1473 if (nh) { 1474 if (!nexthop_get(nh)) { 1475 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1476 err = -EINVAL; 1477 } else { 1478 err = 0; 1479 fi->nh = nh; 1480 } 1481 } else { 1482 change_nexthops(fi) { 1483 nexthop_nh->nh_parent = fi; 1484 } endfor_nexthops(fi) 1485 1486 if (cfg->fc_mp) 1487 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1488 extack); 1489 else 1490 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1491 } 1492 1493 if (err != 0) 1494 goto failure; 1495 1496 if (fib_props[cfg->fc_type].error) { 1497 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1498 NL_SET_ERR_MSG(extack, 1499 "Gateway, device and multipath can not be specified for this route type"); 1500 goto err_inval; 1501 } 1502 goto link_it; 1503 } else { 1504 switch (cfg->fc_type) { 1505 case RTN_UNICAST: 1506 case RTN_LOCAL: 1507 case RTN_BROADCAST: 1508 case RTN_ANYCAST: 1509 case RTN_MULTICAST: 1510 break; 1511 default: 1512 NL_SET_ERR_MSG(extack, "Invalid route type"); 1513 goto err_inval; 1514 } 1515 } 1516 1517 if (cfg->fc_scope > RT_SCOPE_HOST) { 1518 NL_SET_ERR_MSG(extack, "Invalid scope"); 1519 goto err_inval; 1520 } 1521 1522 if (fi->nh) { 1523 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1524 if (err) 1525 goto failure; 1526 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1527 struct fib_nh *nh = fi->fib_nh; 1528 1529 /* Local address is added. */ 1530 if (nhs != 1) { 1531 NL_SET_ERR_MSG(extack, 1532 "Route with host scope can not have multiple nexthops"); 1533 goto err_inval; 1534 } 1535 if (nh->fib_nh_gw_family) { 1536 NL_SET_ERR_MSG(extack, 1537 "Route with host scope can not have a gateway"); 1538 goto err_inval; 1539 } 1540 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1541 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1542 err = -ENODEV; 1543 if (!nh->fib_nh_dev) 1544 goto failure; 1545 } else { 1546 int linkdown = 0; 1547 1548 change_nexthops(fi) { 1549 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1550 cfg->fc_table, cfg->fc_scope, 1551 extack); 1552 if (err != 0) 1553 goto failure; 1554 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1555 linkdown++; 1556 } endfor_nexthops(fi) 1557 if (linkdown == fi->fib_nhs) 1558 fi->fib_flags |= RTNH_F_LINKDOWN; 1559 } 1560 1561 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1562 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1563 goto err_inval; 1564 } 1565 1566 if (!fi->nh) { 1567 change_nexthops(fi) { 1568 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1569 fi->fib_scope); 1570 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1571 fi->fib_nh_is_v6 = true; 1572 } endfor_nexthops(fi) 1573 1574 fib_rebalance(fi); 1575 } 1576 1577 link_it: 1578 ofi = fib_find_info(fi); 1579 if (ofi) { 1580 fi->fib_dead = 1; 1581 free_fib_info(fi); 1582 refcount_inc(&ofi->fib_treeref); 1583 return ofi; 1584 } 1585 1586 refcount_set(&fi->fib_treeref, 1); 1587 refcount_set(&fi->fib_clntref, 1); 1588 spin_lock_bh(&fib_info_lock); 1589 hlist_add_head(&fi->fib_hash, 1590 &fib_info_hash[fib_info_hashfn(fi)]); 1591 if (fi->fib_prefsrc) { 1592 struct hlist_head *head; 1593 1594 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1595 hlist_add_head(&fi->fib_lhash, head); 1596 } 1597 if (fi->nh) { 1598 list_add(&fi->nh_list, &nh->fi_list); 1599 } else { 1600 change_nexthops(fi) { 1601 struct hlist_head *head; 1602 unsigned int hash; 1603 1604 if (!nexthop_nh->fib_nh_dev) 1605 continue; 1606 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex); 1607 head = &fib_info_devhash[hash]; 1608 hlist_add_head(&nexthop_nh->nh_hash, head); 1609 } endfor_nexthops(fi) 1610 } 1611 spin_unlock_bh(&fib_info_lock); 1612 return fi; 1613 1614 err_inval: 1615 err = -EINVAL; 1616 1617 failure: 1618 if (fi) { 1619 fi->fib_dead = 1; 1620 free_fib_info(fi); 1621 } 1622 1623 return ERR_PTR(err); 1624 } 1625 1626 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1627 u8 rt_family, unsigned char *flags, bool skip_oif) 1628 { 1629 if (nhc->nhc_flags & RTNH_F_DEAD) 1630 *flags |= RTNH_F_DEAD; 1631 1632 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1633 *flags |= RTNH_F_LINKDOWN; 1634 1635 rcu_read_lock(); 1636 switch (nhc->nhc_family) { 1637 case AF_INET: 1638 if (ip_ignore_linkdown(nhc->nhc_dev)) 1639 *flags |= RTNH_F_DEAD; 1640 break; 1641 case AF_INET6: 1642 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1643 *flags |= RTNH_F_DEAD; 1644 break; 1645 } 1646 rcu_read_unlock(); 1647 } 1648 1649 switch (nhc->nhc_gw_family) { 1650 case AF_INET: 1651 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1652 goto nla_put_failure; 1653 break; 1654 case AF_INET6: 1655 /* if gateway family does not match nexthop family 1656 * gateway is encoded as RTA_VIA 1657 */ 1658 if (rt_family != nhc->nhc_gw_family) { 1659 int alen = sizeof(struct in6_addr); 1660 struct nlattr *nla; 1661 struct rtvia *via; 1662 1663 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1664 if (!nla) 1665 goto nla_put_failure; 1666 1667 via = nla_data(nla); 1668 via->rtvia_family = AF_INET6; 1669 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1670 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1671 &nhc->nhc_gw.ipv6) < 0) { 1672 goto nla_put_failure; 1673 } 1674 break; 1675 } 1676 1677 *flags |= (nhc->nhc_flags & 1678 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); 1679 1680 if (!skip_oif && nhc->nhc_dev && 1681 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1682 goto nla_put_failure; 1683 1684 if (nhc->nhc_lwtstate && 1685 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1686 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1687 goto nla_put_failure; 1688 1689 return 0; 1690 1691 nla_put_failure: 1692 return -EMSGSIZE; 1693 } 1694 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1695 1696 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1697 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1698 int nh_weight, u8 rt_family, u32 nh_tclassid) 1699 { 1700 const struct net_device *dev = nhc->nhc_dev; 1701 struct rtnexthop *rtnh; 1702 unsigned char flags = 0; 1703 1704 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1705 if (!rtnh) 1706 goto nla_put_failure; 1707 1708 rtnh->rtnh_hops = nh_weight - 1; 1709 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1710 1711 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1712 goto nla_put_failure; 1713 1714 rtnh->rtnh_flags = flags; 1715 1716 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1717 goto nla_put_failure; 1718 1719 /* length of rtnetlink header + attributes */ 1720 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1721 1722 return 0; 1723 1724 nla_put_failure: 1725 return -EMSGSIZE; 1726 } 1727 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1728 #endif 1729 1730 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1731 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1732 { 1733 struct nlattr *mp; 1734 1735 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1736 if (!mp) 1737 goto nla_put_failure; 1738 1739 if (unlikely(fi->nh)) { 1740 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1741 goto nla_put_failure; 1742 goto mp_end; 1743 } 1744 1745 for_nexthops(fi) { 1746 u32 nh_tclassid = 0; 1747 #ifdef CONFIG_IP_ROUTE_CLASSID 1748 nh_tclassid = nh->nh_tclassid; 1749 #endif 1750 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1751 AF_INET, nh_tclassid) < 0) 1752 goto nla_put_failure; 1753 } endfor_nexthops(fi); 1754 1755 mp_end: 1756 nla_nest_end(skb, mp); 1757 1758 return 0; 1759 1760 nla_put_failure: 1761 return -EMSGSIZE; 1762 } 1763 #else 1764 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1765 { 1766 return 0; 1767 } 1768 #endif 1769 1770 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1771 const struct fib_rt_info *fri, unsigned int flags) 1772 { 1773 unsigned int nhs = fib_info_num_path(fri->fi); 1774 struct fib_info *fi = fri->fi; 1775 u32 tb_id = fri->tb_id; 1776 struct nlmsghdr *nlh; 1777 struct rtmsg *rtm; 1778 1779 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1780 if (!nlh) 1781 return -EMSGSIZE; 1782 1783 rtm = nlmsg_data(nlh); 1784 rtm->rtm_family = AF_INET; 1785 rtm->rtm_dst_len = fri->dst_len; 1786 rtm->rtm_src_len = 0; 1787 rtm->rtm_tos = fri->tos; 1788 if (tb_id < 256) 1789 rtm->rtm_table = tb_id; 1790 else 1791 rtm->rtm_table = RT_TABLE_COMPAT; 1792 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1793 goto nla_put_failure; 1794 rtm->rtm_type = fri->type; 1795 rtm->rtm_flags = fi->fib_flags; 1796 rtm->rtm_scope = fi->fib_scope; 1797 rtm->rtm_protocol = fi->fib_protocol; 1798 1799 if (rtm->rtm_dst_len && 1800 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1801 goto nla_put_failure; 1802 if (fi->fib_priority && 1803 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1804 goto nla_put_failure; 1805 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1806 goto nla_put_failure; 1807 1808 if (fi->fib_prefsrc && 1809 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1810 goto nla_put_failure; 1811 1812 if (fi->nh) { 1813 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1814 goto nla_put_failure; 1815 if (nexthop_is_blackhole(fi->nh)) 1816 rtm->rtm_type = RTN_BLACKHOLE; 1817 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode) 1818 goto offload; 1819 } 1820 1821 if (nhs == 1) { 1822 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1823 unsigned char flags = 0; 1824 1825 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1826 goto nla_put_failure; 1827 1828 rtm->rtm_flags = flags; 1829 #ifdef CONFIG_IP_ROUTE_CLASSID 1830 if (nhc->nhc_family == AF_INET) { 1831 struct fib_nh *nh; 1832 1833 nh = container_of(nhc, struct fib_nh, nh_common); 1834 if (nh->nh_tclassid && 1835 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1836 goto nla_put_failure; 1837 } 1838 #endif 1839 } else { 1840 if (fib_add_multipath(skb, fi) < 0) 1841 goto nla_put_failure; 1842 } 1843 1844 offload: 1845 if (fri->offload) 1846 rtm->rtm_flags |= RTM_F_OFFLOAD; 1847 if (fri->trap) 1848 rtm->rtm_flags |= RTM_F_TRAP; 1849 if (fri->offload_failed) 1850 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; 1851 1852 nlmsg_end(skb, nlh); 1853 return 0; 1854 1855 nla_put_failure: 1856 nlmsg_cancel(skb, nlh); 1857 return -EMSGSIZE; 1858 } 1859 1860 /* 1861 * Update FIB if: 1862 * - local address disappeared -> we must delete all the entries 1863 * referring to it. 1864 * - device went down -> we must shutdown all nexthops going via it. 1865 */ 1866 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1867 { 1868 int ret = 0; 1869 unsigned int hash = fib_laddr_hashfn(local); 1870 struct hlist_head *head = &fib_info_laddrhash[hash]; 1871 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1872 struct net *net = dev_net(dev); 1873 struct fib_info *fi; 1874 1875 if (!fib_info_laddrhash || local == 0) 1876 return 0; 1877 1878 hlist_for_each_entry(fi, head, fib_lhash) { 1879 if (!net_eq(fi->fib_net, net) || 1880 fi->fib_tb_id != tb_id) 1881 continue; 1882 if (fi->fib_prefsrc == local) { 1883 fi->fib_flags |= RTNH_F_DEAD; 1884 ret++; 1885 } 1886 } 1887 return ret; 1888 } 1889 1890 static int call_fib_nh_notifiers(struct fib_nh *nh, 1891 enum fib_event_type event_type) 1892 { 1893 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1894 struct fib_nh_notifier_info info = { 1895 .fib_nh = nh, 1896 }; 1897 1898 switch (event_type) { 1899 case FIB_EVENT_NH_ADD: 1900 if (nh->fib_nh_flags & RTNH_F_DEAD) 1901 break; 1902 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1903 break; 1904 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1905 &info.info); 1906 case FIB_EVENT_NH_DEL: 1907 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1908 (nh->fib_nh_flags & RTNH_F_DEAD)) 1909 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1910 event_type, &info.info); 1911 break; 1912 default: 1913 break; 1914 } 1915 1916 return NOTIFY_DONE; 1917 } 1918 1919 /* Update the PMTU of exceptions when: 1920 * - the new MTU of the first hop becomes smaller than the PMTU 1921 * - the old MTU was the same as the PMTU, and it limited discovery of 1922 * larger MTUs on the path. With that limit raised, we can now 1923 * discover larger MTUs 1924 * A special case is locked exceptions, for which the PMTU is smaller 1925 * than the minimal accepted PMTU: 1926 * - if the new MTU is greater than the PMTU, don't make any change 1927 * - otherwise, unlock and set PMTU 1928 */ 1929 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1930 { 1931 struct fnhe_hash_bucket *bucket; 1932 int i; 1933 1934 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1935 if (!bucket) 1936 return; 1937 1938 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1939 struct fib_nh_exception *fnhe; 1940 1941 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1942 fnhe; 1943 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1944 if (fnhe->fnhe_mtu_locked) { 1945 if (new <= fnhe->fnhe_pmtu) { 1946 fnhe->fnhe_pmtu = new; 1947 fnhe->fnhe_mtu_locked = false; 1948 } 1949 } else if (new < fnhe->fnhe_pmtu || 1950 orig == fnhe->fnhe_pmtu) { 1951 fnhe->fnhe_pmtu = new; 1952 } 1953 } 1954 } 1955 } 1956 1957 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1958 { 1959 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1960 struct hlist_head *head = &fib_info_devhash[hash]; 1961 struct fib_nh *nh; 1962 1963 hlist_for_each_entry(nh, head, nh_hash) { 1964 if (nh->fib_nh_dev == dev) 1965 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1966 } 1967 } 1968 1969 /* Event force Flags Description 1970 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1971 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1972 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1973 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1974 * 1975 * only used when fib_nh is built into fib_info 1976 */ 1977 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1978 { 1979 int ret = 0; 1980 int scope = RT_SCOPE_NOWHERE; 1981 struct fib_info *prev_fi = NULL; 1982 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1983 struct hlist_head *head = &fib_info_devhash[hash]; 1984 struct fib_nh *nh; 1985 1986 if (force) 1987 scope = -1; 1988 1989 hlist_for_each_entry(nh, head, nh_hash) { 1990 struct fib_info *fi = nh->nh_parent; 1991 int dead; 1992 1993 BUG_ON(!fi->fib_nhs); 1994 if (nh->fib_nh_dev != dev || fi == prev_fi) 1995 continue; 1996 prev_fi = fi; 1997 dead = 0; 1998 change_nexthops(fi) { 1999 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2000 dead++; 2001 else if (nexthop_nh->fib_nh_dev == dev && 2002 nexthop_nh->fib_nh_scope != scope) { 2003 switch (event) { 2004 case NETDEV_DOWN: 2005 case NETDEV_UNREGISTER: 2006 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2007 fallthrough; 2008 case NETDEV_CHANGE: 2009 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2010 break; 2011 } 2012 call_fib_nh_notifiers(nexthop_nh, 2013 FIB_EVENT_NH_DEL); 2014 dead++; 2015 } 2016 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2017 if (event == NETDEV_UNREGISTER && 2018 nexthop_nh->fib_nh_dev == dev) { 2019 dead = fi->fib_nhs; 2020 break; 2021 } 2022 #endif 2023 } endfor_nexthops(fi) 2024 if (dead == fi->fib_nhs) { 2025 switch (event) { 2026 case NETDEV_DOWN: 2027 case NETDEV_UNREGISTER: 2028 fi->fib_flags |= RTNH_F_DEAD; 2029 fallthrough; 2030 case NETDEV_CHANGE: 2031 fi->fib_flags |= RTNH_F_LINKDOWN; 2032 break; 2033 } 2034 ret++; 2035 } 2036 2037 fib_rebalance(fi); 2038 } 2039 2040 return ret; 2041 } 2042 2043 /* Must be invoked inside of an RCU protected region. */ 2044 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2045 { 2046 struct fib_info *fi = NULL, *last_resort = NULL; 2047 struct hlist_head *fa_head = res->fa_head; 2048 struct fib_table *tb = res->table; 2049 u8 slen = 32 - res->prefixlen; 2050 int order = -1, last_idx = -1; 2051 struct fib_alias *fa, *fa1 = NULL; 2052 u32 last_prio = res->fi->fib_priority; 2053 u8 last_tos = 0; 2054 2055 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2056 struct fib_info *next_fi = fa->fa_info; 2057 struct fib_nh_common *nhc; 2058 2059 if (fa->fa_slen != slen) 2060 continue; 2061 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 2062 continue; 2063 if (fa->tb_id != tb->tb_id) 2064 continue; 2065 if (next_fi->fib_priority > last_prio && 2066 fa->fa_tos == last_tos) { 2067 if (last_tos) 2068 continue; 2069 break; 2070 } 2071 if (next_fi->fib_flags & RTNH_F_DEAD) 2072 continue; 2073 last_tos = fa->fa_tos; 2074 last_prio = next_fi->fib_priority; 2075 2076 if (next_fi->fib_scope != res->scope || 2077 fa->fa_type != RTN_UNICAST) 2078 continue; 2079 2080 nhc = fib_info_nhc(next_fi, 0); 2081 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2082 continue; 2083 2084 fib_alias_accessed(fa); 2085 2086 if (!fi) { 2087 if (next_fi != res->fi) 2088 break; 2089 fa1 = fa; 2090 } else if (!fib_detect_death(fi, order, &last_resort, 2091 &last_idx, fa1->fa_default)) { 2092 fib_result_assign(res, fi); 2093 fa1->fa_default = order; 2094 goto out; 2095 } 2096 fi = next_fi; 2097 order++; 2098 } 2099 2100 if (order <= 0 || !fi) { 2101 if (fa1) 2102 fa1->fa_default = -1; 2103 goto out; 2104 } 2105 2106 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2107 fa1->fa_default)) { 2108 fib_result_assign(res, fi); 2109 fa1->fa_default = order; 2110 goto out; 2111 } 2112 2113 if (last_idx >= 0) 2114 fib_result_assign(res, last_resort); 2115 fa1->fa_default = last_idx; 2116 out: 2117 return; 2118 } 2119 2120 /* 2121 * Dead device goes up. We wake up dead nexthops. 2122 * It takes sense only on multipath routes. 2123 * 2124 * only used when fib_nh is built into fib_info 2125 */ 2126 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2127 { 2128 struct fib_info *prev_fi; 2129 unsigned int hash; 2130 struct hlist_head *head; 2131 struct fib_nh *nh; 2132 int ret; 2133 2134 if (!(dev->flags & IFF_UP)) 2135 return 0; 2136 2137 if (nh_flags & RTNH_F_DEAD) { 2138 unsigned int flags = dev_get_flags(dev); 2139 2140 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2141 nh_flags |= RTNH_F_LINKDOWN; 2142 } 2143 2144 prev_fi = NULL; 2145 hash = fib_devindex_hashfn(dev->ifindex); 2146 head = &fib_info_devhash[hash]; 2147 ret = 0; 2148 2149 hlist_for_each_entry(nh, head, nh_hash) { 2150 struct fib_info *fi = nh->nh_parent; 2151 int alive; 2152 2153 BUG_ON(!fi->fib_nhs); 2154 if (nh->fib_nh_dev != dev || fi == prev_fi) 2155 continue; 2156 2157 prev_fi = fi; 2158 alive = 0; 2159 change_nexthops(fi) { 2160 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2161 alive++; 2162 continue; 2163 } 2164 if (!nexthop_nh->fib_nh_dev || 2165 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2166 continue; 2167 if (nexthop_nh->fib_nh_dev != dev || 2168 !__in_dev_get_rtnl(dev)) 2169 continue; 2170 alive++; 2171 nexthop_nh->fib_nh_flags &= ~nh_flags; 2172 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2173 } endfor_nexthops(fi) 2174 2175 if (alive > 0) { 2176 fi->fib_flags &= ~nh_flags; 2177 ret++; 2178 } 2179 2180 fib_rebalance(fi); 2181 } 2182 2183 return ret; 2184 } 2185 2186 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2187 static bool fib_good_nh(const struct fib_nh *nh) 2188 { 2189 int state = NUD_REACHABLE; 2190 2191 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2192 struct neighbour *n; 2193 2194 rcu_read_lock_bh(); 2195 2196 if (likely(nh->fib_nh_gw_family == AF_INET)) 2197 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2198 (__force u32)nh->fib_nh_gw4); 2199 else if (nh->fib_nh_gw_family == AF_INET6) 2200 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2201 &nh->fib_nh_gw6); 2202 else 2203 n = NULL; 2204 if (n) 2205 state = n->nud_state; 2206 2207 rcu_read_unlock_bh(); 2208 } 2209 2210 return !!(state & NUD_VALID); 2211 } 2212 2213 void fib_select_multipath(struct fib_result *res, int hash) 2214 { 2215 struct fib_info *fi = res->fi; 2216 struct net *net = fi->fib_net; 2217 bool first = false; 2218 2219 if (unlikely(res->fi->nh)) { 2220 nexthop_path_fib_result(res, hash); 2221 return; 2222 } 2223 2224 change_nexthops(fi) { 2225 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 2226 if (!fib_good_nh(nexthop_nh)) 2227 continue; 2228 if (!first) { 2229 res->nh_sel = nhsel; 2230 res->nhc = &nexthop_nh->nh_common; 2231 first = true; 2232 } 2233 } 2234 2235 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2236 continue; 2237 2238 res->nh_sel = nhsel; 2239 res->nhc = &nexthop_nh->nh_common; 2240 return; 2241 } endfor_nexthops(fi); 2242 } 2243 #endif 2244 2245 void fib_select_path(struct net *net, struct fib_result *res, 2246 struct flowi4 *fl4, const struct sk_buff *skb) 2247 { 2248 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 2249 goto check_saddr; 2250 2251 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2252 if (fib_info_num_path(res->fi) > 1) { 2253 int h = fib_multipath_hash(net, fl4, skb, NULL); 2254 2255 fib_select_multipath(res, h); 2256 } 2257 else 2258 #endif 2259 if (!res->prefixlen && 2260 res->table->tb_num_default > 1 && 2261 res->type == RTN_UNICAST) 2262 fib_select_default(fl4, res); 2263 2264 check_saddr: 2265 if (!fl4->saddr) 2266 fl4->saddr = fib_result_prefsrc(net, res); 2267 } 2268