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