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