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