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 sk_buff *skb; 508 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 509 int err = -ENOBUFS; 510 511 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 512 if (!skb) 513 goto errout; 514 515 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 516 fa->fa_type, key, dst_len, 517 fa->fa_tos, fa->fa_info, nlm_flags); 518 if (err < 0) { 519 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 520 WARN_ON(err == -EMSGSIZE); 521 kfree_skb(skb); 522 goto errout; 523 } 524 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 525 info->nlh, GFP_KERNEL); 526 return; 527 errout: 528 if (err < 0) 529 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 530 } 531 532 static int fib_detect_death(struct fib_info *fi, int order, 533 struct fib_info **last_resort, int *last_idx, 534 int dflt) 535 { 536 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 537 struct neighbour *n; 538 int state = NUD_NONE; 539 540 if (likely(nhc->nhc_gw_family == AF_INET)) 541 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 542 else if (nhc->nhc_gw_family == AF_INET6) 543 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 544 nhc->nhc_dev); 545 else 546 n = NULL; 547 548 if (n) { 549 state = n->nud_state; 550 neigh_release(n); 551 } else { 552 return 0; 553 } 554 if (state == NUD_REACHABLE) 555 return 0; 556 if ((state & NUD_VALID) && order != dflt) 557 return 0; 558 if ((state & NUD_VALID) || 559 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 560 *last_resort = fi; 561 *last_idx = order; 562 } 563 return 1; 564 } 565 566 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap, 567 u16 encap_type, void *cfg, gfp_t gfp_flags, 568 struct netlink_ext_ack *extack) 569 { 570 int err; 571 572 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 573 gfp_flags); 574 if (!nhc->nhc_pcpu_rth_output) 575 return -ENOMEM; 576 577 if (encap) { 578 struct lwtunnel_state *lwtstate; 579 580 if (encap_type == LWTUNNEL_ENCAP_NONE) { 581 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 582 err = -EINVAL; 583 goto lwt_failure; 584 } 585 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family, 586 cfg, &lwtstate, extack); 587 if (err) 588 goto lwt_failure; 589 590 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 591 } 592 593 return 0; 594 595 lwt_failure: 596 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 597 nhc->nhc_pcpu_rth_output = NULL; 598 return err; 599 } 600 EXPORT_SYMBOL_GPL(fib_nh_common_init); 601 602 int fib_nh_init(struct net *net, struct fib_nh *nh, 603 struct fib_config *cfg, int nh_weight, 604 struct netlink_ext_ack *extack) 605 { 606 int err; 607 608 nh->fib_nh_family = AF_INET; 609 610 err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap, 611 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 612 if (err) 613 return err; 614 615 nh->fib_nh_oif = cfg->fc_oif; 616 nh->fib_nh_gw_family = cfg->fc_gw_family; 617 if (cfg->fc_gw_family == AF_INET) 618 nh->fib_nh_gw4 = cfg->fc_gw4; 619 else if (cfg->fc_gw_family == AF_INET6) 620 nh->fib_nh_gw6 = cfg->fc_gw6; 621 622 nh->fib_nh_flags = cfg->fc_flags; 623 624 #ifdef CONFIG_IP_ROUTE_CLASSID 625 nh->nh_tclassid = cfg->fc_flow; 626 if (nh->nh_tclassid) 627 net->ipv4.fib_num_tclassid_users++; 628 #endif 629 #ifdef CONFIG_IP_ROUTE_MULTIPATH 630 nh->fib_nh_weight = nh_weight; 631 #endif 632 return 0; 633 } 634 635 #ifdef CONFIG_IP_ROUTE_MULTIPATH 636 637 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 638 struct netlink_ext_ack *extack) 639 { 640 int nhs = 0; 641 642 while (rtnh_ok(rtnh, remaining)) { 643 nhs++; 644 rtnh = rtnh_next(rtnh, &remaining); 645 } 646 647 /* leftover implies invalid nexthop configuration, discard it */ 648 if (remaining > 0) { 649 NL_SET_ERR_MSG(extack, 650 "Invalid nexthop configuration - extra data after nexthops"); 651 nhs = 0; 652 } 653 654 return nhs; 655 } 656 657 /* only called when fib_nh is integrated into fib_info */ 658 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 659 int remaining, struct fib_config *cfg, 660 struct netlink_ext_ack *extack) 661 { 662 struct net *net = fi->fib_net; 663 struct fib_config fib_cfg; 664 struct fib_nh *nh; 665 int ret; 666 667 change_nexthops(fi) { 668 int attrlen; 669 670 memset(&fib_cfg, 0, sizeof(fib_cfg)); 671 672 if (!rtnh_ok(rtnh, remaining)) { 673 NL_SET_ERR_MSG(extack, 674 "Invalid nexthop configuration - extra data after nexthop"); 675 return -EINVAL; 676 } 677 678 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 679 NL_SET_ERR_MSG(extack, 680 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 681 return -EINVAL; 682 } 683 684 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 685 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 686 687 attrlen = rtnh_attrlen(rtnh); 688 if (attrlen > 0) { 689 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 690 691 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 692 nlav = nla_find(attrs, attrlen, RTA_VIA); 693 if (nla && nlav) { 694 NL_SET_ERR_MSG(extack, 695 "Nexthop configuration can not contain both GATEWAY and VIA"); 696 return -EINVAL; 697 } 698 if (nla) { 699 fib_cfg.fc_gw4 = nla_get_in_addr(nla); 700 if (fib_cfg.fc_gw4) 701 fib_cfg.fc_gw_family = AF_INET; 702 } else if (nlav) { 703 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 704 if (ret) 705 goto errout; 706 } 707 708 nla = nla_find(attrs, attrlen, RTA_FLOW); 709 if (nla) 710 fib_cfg.fc_flow = nla_get_u32(nla); 711 712 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 713 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 714 if (nla) 715 fib_cfg.fc_encap_type = nla_get_u16(nla); 716 } 717 718 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 719 rtnh->rtnh_hops + 1, extack); 720 if (ret) 721 goto errout; 722 723 rtnh = rtnh_next(rtnh, &remaining); 724 } endfor_nexthops(fi); 725 726 ret = -EINVAL; 727 nh = fib_info_nh(fi, 0); 728 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 729 NL_SET_ERR_MSG(extack, 730 "Nexthop device index does not match RTA_OIF"); 731 goto errout; 732 } 733 if (cfg->fc_gw_family) { 734 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 735 (cfg->fc_gw_family == AF_INET && 736 nh->fib_nh_gw4 != cfg->fc_gw4) || 737 (cfg->fc_gw_family == AF_INET6 && 738 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 739 NL_SET_ERR_MSG(extack, 740 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 741 goto errout; 742 } 743 } 744 #ifdef CONFIG_IP_ROUTE_CLASSID 745 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 746 NL_SET_ERR_MSG(extack, 747 "Nexthop class id does not match RTA_FLOW"); 748 goto errout; 749 } 750 #endif 751 ret = 0; 752 errout: 753 return ret; 754 } 755 756 /* only called when fib_nh is integrated into fib_info */ 757 static void fib_rebalance(struct fib_info *fi) 758 { 759 int total; 760 int w; 761 762 if (fib_info_num_path(fi) < 2) 763 return; 764 765 total = 0; 766 for_nexthops(fi) { 767 if (nh->fib_nh_flags & RTNH_F_DEAD) 768 continue; 769 770 if (ip_ignore_linkdown(nh->fib_nh_dev) && 771 nh->fib_nh_flags & RTNH_F_LINKDOWN) 772 continue; 773 774 total += nh->fib_nh_weight; 775 } endfor_nexthops(fi); 776 777 w = 0; 778 change_nexthops(fi) { 779 int upper_bound; 780 781 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 782 upper_bound = -1; 783 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 784 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 785 upper_bound = -1; 786 } else { 787 w += nexthop_nh->fib_nh_weight; 788 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 789 total) - 1; 790 } 791 792 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 793 } endfor_nexthops(fi); 794 } 795 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 796 797 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 798 int remaining, struct fib_config *cfg, 799 struct netlink_ext_ack *extack) 800 { 801 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 802 803 return -EINVAL; 804 } 805 806 #define fib_rebalance(fi) do { } while (0) 807 808 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 809 810 static int fib_encap_match(u16 encap_type, 811 struct nlattr *encap, 812 const struct fib_nh *nh, 813 const struct fib_config *cfg, 814 struct netlink_ext_ack *extack) 815 { 816 struct lwtunnel_state *lwtstate; 817 int ret, result = 0; 818 819 if (encap_type == LWTUNNEL_ENCAP_NONE) 820 return 0; 821 822 ret = lwtunnel_build_state(encap_type, encap, AF_INET, 823 cfg, &lwtstate, extack); 824 if (!ret) { 825 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 826 lwtstate_free(lwtstate); 827 } 828 829 return result; 830 } 831 832 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, 833 struct netlink_ext_ack *extack) 834 { 835 #ifdef CONFIG_IP_ROUTE_MULTIPATH 836 struct rtnexthop *rtnh; 837 int remaining; 838 #endif 839 840 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 841 return 1; 842 843 if (cfg->fc_nh_id) { 844 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 845 return 0; 846 return 1; 847 } 848 849 if (cfg->fc_oif || cfg->fc_gw_family) { 850 struct fib_nh *nh = fib_info_nh(fi, 0); 851 852 if (cfg->fc_encap) { 853 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap, 854 nh, cfg, extack)) 855 return 1; 856 } 857 #ifdef CONFIG_IP_ROUTE_CLASSID 858 if (cfg->fc_flow && 859 cfg->fc_flow != nh->nh_tclassid) 860 return 1; 861 #endif 862 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 863 (cfg->fc_gw_family && 864 cfg->fc_gw_family != nh->fib_nh_gw_family)) 865 return 1; 866 867 if (cfg->fc_gw_family == AF_INET && 868 cfg->fc_gw4 != nh->fib_nh_gw4) 869 return 1; 870 871 if (cfg->fc_gw_family == AF_INET6 && 872 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 873 return 1; 874 875 return 0; 876 } 877 878 #ifdef CONFIG_IP_ROUTE_MULTIPATH 879 if (!cfg->fc_mp) 880 return 0; 881 882 rtnh = cfg->fc_mp; 883 remaining = cfg->fc_mp_len; 884 885 for_nexthops(fi) { 886 int attrlen; 887 888 if (!rtnh_ok(rtnh, remaining)) 889 return -EINVAL; 890 891 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 892 return 1; 893 894 attrlen = rtnh_attrlen(rtnh); 895 if (attrlen > 0) { 896 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 897 898 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 899 nlav = nla_find(attrs, attrlen, RTA_VIA); 900 if (nla && nlav) { 901 NL_SET_ERR_MSG(extack, 902 "Nexthop configuration can not contain both GATEWAY and VIA"); 903 return -EINVAL; 904 } 905 906 if (nla) { 907 if (nh->fib_nh_gw_family != AF_INET || 908 nla_get_in_addr(nla) != nh->fib_nh_gw4) 909 return 1; 910 } else if (nlav) { 911 struct fib_config cfg2; 912 int err; 913 914 err = fib_gw_from_via(&cfg2, nlav, extack); 915 if (err) 916 return err; 917 918 switch (nh->fib_nh_gw_family) { 919 case AF_INET: 920 if (cfg2.fc_gw_family != AF_INET || 921 cfg2.fc_gw4 != nh->fib_nh_gw4) 922 return 1; 923 break; 924 case AF_INET6: 925 if (cfg2.fc_gw_family != AF_INET6 || 926 ipv6_addr_cmp(&cfg2.fc_gw6, 927 &nh->fib_nh_gw6)) 928 return 1; 929 break; 930 } 931 } 932 933 #ifdef CONFIG_IP_ROUTE_CLASSID 934 nla = nla_find(attrs, attrlen, RTA_FLOW); 935 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 936 return 1; 937 #endif 938 } 939 940 rtnh = rtnh_next(rtnh, &remaining); 941 } endfor_nexthops(fi); 942 #endif 943 return 0; 944 } 945 946 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 947 { 948 struct nlattr *nla; 949 int remaining; 950 951 if (!cfg->fc_mx) 952 return true; 953 954 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 955 int type = nla_type(nla); 956 u32 fi_val, val; 957 958 if (!type) 959 continue; 960 if (type > RTAX_MAX) 961 return false; 962 963 if (type == RTAX_CC_ALGO) { 964 char tmp[TCP_CA_NAME_MAX]; 965 bool ecn_ca = false; 966 967 nla_strlcpy(tmp, nla, sizeof(tmp)); 968 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 969 } else { 970 if (nla_len(nla) != sizeof(u32)) 971 return false; 972 val = nla_get_u32(nla); 973 } 974 975 fi_val = fi->fib_metrics->metrics[type - 1]; 976 if (type == RTAX_FEATURES) 977 fi_val &= ~DST_FEATURE_ECN_CA; 978 979 if (fi_val != val) 980 return false; 981 } 982 983 return true; 984 } 985 986 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 987 u32 table, struct netlink_ext_ack *extack) 988 { 989 struct fib6_config cfg = { 990 .fc_table = table, 991 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 992 .fc_ifindex = nh->fib_nh_oif, 993 .fc_gateway = nh->fib_nh_gw6, 994 }; 995 struct fib6_nh fib6_nh = {}; 996 int err; 997 998 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 999 if (!err) { 1000 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1001 dev_hold(nh->fib_nh_dev); 1002 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1003 nh->fib_nh_scope = RT_SCOPE_LINK; 1004 1005 ipv6_stub->fib6_nh_release(&fib6_nh); 1006 } 1007 1008 return err; 1009 } 1010 1011 /* 1012 * Picture 1013 * ------- 1014 * 1015 * Semantics of nexthop is very messy by historical reasons. 1016 * We have to take into account, that: 1017 * a) gateway can be actually local interface address, 1018 * so that gatewayed route is direct. 1019 * b) gateway must be on-link address, possibly 1020 * described not by an ifaddr, but also by a direct route. 1021 * c) If both gateway and interface are specified, they should not 1022 * contradict. 1023 * d) If we use tunnel routes, gateway could be not on-link. 1024 * 1025 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1026 * results in pretty ugly and hairy code with obscure logic. 1027 * 1028 * I chose to generalized it instead, so that the size 1029 * of code does not increase practically, but it becomes 1030 * much more general. 1031 * Every prefix is assigned a "scope" value: "host" is local address, 1032 * "link" is direct route, 1033 * [ ... "site" ... "interior" ... ] 1034 * and "universe" is true gateway route with global meaning. 1035 * 1036 * Every prefix refers to a set of "nexthop"s (gw, oif), 1037 * where gw must have narrower scope. This recursion stops 1038 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1039 * which means that gw is forced to be on link. 1040 * 1041 * Code is still hairy, but now it is apparently logically 1042 * consistent and very flexible. F.e. as by-product it allows 1043 * to co-exists in peace independent exterior and interior 1044 * routing processes. 1045 * 1046 * Normally it looks as following. 1047 * 1048 * {universe prefix} -> (gw, oif) [scope link] 1049 * | 1050 * |-> {link prefix} -> (gw, oif) [scope local] 1051 * | 1052 * |-> {local prefix} (terminal node) 1053 */ 1054 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1055 u8 scope, struct netlink_ext_ack *extack) 1056 { 1057 struct net_device *dev; 1058 struct fib_result res; 1059 int err = 0; 1060 1061 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1062 unsigned int addr_type; 1063 1064 if (scope >= RT_SCOPE_LINK) { 1065 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1066 return -EINVAL; 1067 } 1068 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1069 if (!dev) { 1070 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1071 return -ENODEV; 1072 } 1073 if (!(dev->flags & IFF_UP)) { 1074 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1075 return -ENETDOWN; 1076 } 1077 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1078 if (addr_type != RTN_UNICAST) { 1079 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1080 return -EINVAL; 1081 } 1082 if (!netif_carrier_ok(dev)) 1083 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1084 nh->fib_nh_dev = dev; 1085 dev_hold(dev); 1086 nh->fib_nh_scope = RT_SCOPE_LINK; 1087 return 0; 1088 } 1089 rcu_read_lock(); 1090 { 1091 struct fib_table *tbl = NULL; 1092 struct flowi4 fl4 = { 1093 .daddr = nh->fib_nh_gw4, 1094 .flowi4_scope = scope + 1, 1095 .flowi4_oif = nh->fib_nh_oif, 1096 .flowi4_iif = LOOPBACK_IFINDEX, 1097 }; 1098 1099 /* It is not necessary, but requires a bit of thinking */ 1100 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1101 fl4.flowi4_scope = RT_SCOPE_LINK; 1102 1103 if (table) 1104 tbl = fib_get_table(net, table); 1105 1106 if (tbl) 1107 err = fib_table_lookup(tbl, &fl4, &res, 1108 FIB_LOOKUP_IGNORE_LINKSTATE | 1109 FIB_LOOKUP_NOREF); 1110 1111 /* on error or if no table given do full lookup. This 1112 * is needed for example when nexthops are in the local 1113 * table rather than the given table 1114 */ 1115 if (!tbl || err) { 1116 err = fib_lookup(net, &fl4, &res, 1117 FIB_LOOKUP_IGNORE_LINKSTATE); 1118 } 1119 1120 if (err) { 1121 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1122 goto out; 1123 } 1124 } 1125 1126 err = -EINVAL; 1127 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1128 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1129 goto out; 1130 } 1131 nh->fib_nh_scope = res.scope; 1132 nh->fib_nh_oif = FIB_RES_OIF(res); 1133 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1134 if (!dev) { 1135 NL_SET_ERR_MSG(extack, 1136 "No egress device for nexthop gateway"); 1137 goto out; 1138 } 1139 dev_hold(dev); 1140 if (!netif_carrier_ok(dev)) 1141 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1142 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1143 out: 1144 rcu_read_unlock(); 1145 return err; 1146 } 1147 1148 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1149 struct netlink_ext_ack *extack) 1150 { 1151 struct in_device *in_dev; 1152 int err; 1153 1154 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1155 NL_SET_ERR_MSG(extack, 1156 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1157 return -EINVAL; 1158 } 1159 1160 rcu_read_lock(); 1161 1162 err = -ENODEV; 1163 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1164 if (!in_dev) 1165 goto out; 1166 err = -ENETDOWN; 1167 if (!(in_dev->dev->flags & IFF_UP)) { 1168 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1169 goto out; 1170 } 1171 1172 nh->fib_nh_dev = in_dev->dev; 1173 dev_hold(nh->fib_nh_dev); 1174 nh->fib_nh_scope = RT_SCOPE_HOST; 1175 if (!netif_carrier_ok(nh->fib_nh_dev)) 1176 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1177 err = 0; 1178 out: 1179 rcu_read_unlock(); 1180 return err; 1181 } 1182 1183 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1184 struct netlink_ext_ack *extack) 1185 { 1186 int err; 1187 1188 if (nh->fib_nh_gw_family == AF_INET) 1189 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1190 else if (nh->fib_nh_gw_family == AF_INET6) 1191 err = fib_check_nh_v6_gw(net, nh, table, extack); 1192 else 1193 err = fib_check_nh_nongw(net, nh, extack); 1194 1195 return err; 1196 } 1197 1198 static inline unsigned int fib_laddr_hashfn(__be32 val) 1199 { 1200 unsigned int mask = (fib_info_hash_size - 1); 1201 1202 return ((__force u32)val ^ 1203 ((__force u32)val >> 7) ^ 1204 ((__force u32)val >> 14)) & mask; 1205 } 1206 1207 static struct hlist_head *fib_info_hash_alloc(int bytes) 1208 { 1209 if (bytes <= PAGE_SIZE) 1210 return kzalloc(bytes, GFP_KERNEL); 1211 else 1212 return (struct hlist_head *) 1213 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 1214 get_order(bytes)); 1215 } 1216 1217 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 1218 { 1219 if (!hash) 1220 return; 1221 1222 if (bytes <= PAGE_SIZE) 1223 kfree(hash); 1224 else 1225 free_pages((unsigned long) hash, get_order(bytes)); 1226 } 1227 1228 static void fib_info_hash_move(struct hlist_head *new_info_hash, 1229 struct hlist_head *new_laddrhash, 1230 unsigned int new_size) 1231 { 1232 struct hlist_head *old_info_hash, *old_laddrhash; 1233 unsigned int old_size = fib_info_hash_size; 1234 unsigned int i, bytes; 1235 1236 spin_lock_bh(&fib_info_lock); 1237 old_info_hash = fib_info_hash; 1238 old_laddrhash = fib_info_laddrhash; 1239 fib_info_hash_size = new_size; 1240 1241 for (i = 0; i < old_size; i++) { 1242 struct hlist_head *head = &fib_info_hash[i]; 1243 struct hlist_node *n; 1244 struct fib_info *fi; 1245 1246 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1247 struct hlist_head *dest; 1248 unsigned int new_hash; 1249 1250 new_hash = fib_info_hashfn(fi); 1251 dest = &new_info_hash[new_hash]; 1252 hlist_add_head(&fi->fib_hash, dest); 1253 } 1254 } 1255 fib_info_hash = new_info_hash; 1256 1257 for (i = 0; i < old_size; i++) { 1258 struct hlist_head *lhead = &fib_info_laddrhash[i]; 1259 struct hlist_node *n; 1260 struct fib_info *fi; 1261 1262 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1263 struct hlist_head *ldest; 1264 unsigned int new_hash; 1265 1266 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 1267 ldest = &new_laddrhash[new_hash]; 1268 hlist_add_head(&fi->fib_lhash, ldest); 1269 } 1270 } 1271 fib_info_laddrhash = new_laddrhash; 1272 1273 spin_unlock_bh(&fib_info_lock); 1274 1275 bytes = old_size * sizeof(struct hlist_head *); 1276 fib_info_hash_free(old_info_hash, bytes); 1277 fib_info_hash_free(old_laddrhash, bytes); 1278 } 1279 1280 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1281 unsigned char scope) 1282 { 1283 struct fib_nh *nh; 1284 1285 if (nhc->nhc_family != AF_INET) 1286 return inet_select_addr(nhc->nhc_dev, 0, scope); 1287 1288 nh = container_of(nhc, struct fib_nh, nh_common); 1289 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1290 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 1291 1292 return nh->nh_saddr; 1293 } 1294 1295 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1296 { 1297 struct fib_nh_common *nhc = res->nhc; 1298 1299 if (res->fi->fib_prefsrc) 1300 return res->fi->fib_prefsrc; 1301 1302 if (nhc->nhc_family == AF_INET) { 1303 struct fib_nh *nh; 1304 1305 nh = container_of(nhc, struct fib_nh, nh_common); 1306 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid)) 1307 return nh->nh_saddr; 1308 } 1309 1310 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1311 } 1312 1313 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1314 { 1315 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1316 fib_prefsrc != cfg->fc_dst) { 1317 u32 tb_id = cfg->fc_table; 1318 int rc; 1319 1320 if (tb_id == RT_TABLE_MAIN) 1321 tb_id = RT_TABLE_LOCAL; 1322 1323 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1324 fib_prefsrc, tb_id); 1325 1326 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1327 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1328 fib_prefsrc, RT_TABLE_LOCAL); 1329 } 1330 1331 if (rc != RTN_LOCAL) 1332 return false; 1333 } 1334 return true; 1335 } 1336 1337 struct fib_info *fib_create_info(struct fib_config *cfg, 1338 struct netlink_ext_ack *extack) 1339 { 1340 int err; 1341 struct fib_info *fi = NULL; 1342 struct nexthop *nh = NULL; 1343 struct fib_info *ofi; 1344 int nhs = 1; 1345 struct net *net = cfg->fc_nlinfo.nl_net; 1346 1347 if (cfg->fc_type > RTN_MAX) 1348 goto err_inval; 1349 1350 /* Fast check to catch the most weird cases */ 1351 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1352 NL_SET_ERR_MSG(extack, "Invalid scope"); 1353 goto err_inval; 1354 } 1355 1356 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1357 NL_SET_ERR_MSG(extack, 1358 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1359 goto err_inval; 1360 } 1361 1362 if (cfg->fc_nh_id) { 1363 if (!cfg->fc_mx) { 1364 fi = fib_find_info_nh(net, cfg); 1365 if (fi) { 1366 fi->fib_treeref++; 1367 return fi; 1368 } 1369 } 1370 1371 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1372 if (!nh) { 1373 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1374 goto err_inval; 1375 } 1376 nhs = 0; 1377 } 1378 1379 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1380 if (cfg->fc_mp) { 1381 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1382 if (nhs == 0) 1383 goto err_inval; 1384 } 1385 #endif 1386 1387 err = -ENOBUFS; 1388 if (fib_info_cnt >= fib_info_hash_size) { 1389 unsigned int new_size = fib_info_hash_size << 1; 1390 struct hlist_head *new_info_hash; 1391 struct hlist_head *new_laddrhash; 1392 unsigned int bytes; 1393 1394 if (!new_size) 1395 new_size = 16; 1396 bytes = new_size * sizeof(struct hlist_head *); 1397 new_info_hash = fib_info_hash_alloc(bytes); 1398 new_laddrhash = fib_info_hash_alloc(bytes); 1399 if (!new_info_hash || !new_laddrhash) { 1400 fib_info_hash_free(new_info_hash, bytes); 1401 fib_info_hash_free(new_laddrhash, bytes); 1402 } else 1403 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1404 1405 if (!fib_info_hash_size) 1406 goto failure; 1407 } 1408 1409 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1410 if (!fi) 1411 goto failure; 1412 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1413 cfg->fc_mx_len, extack); 1414 if (IS_ERR(fi->fib_metrics)) { 1415 err = PTR_ERR(fi->fib_metrics); 1416 kfree(fi); 1417 return ERR_PTR(err); 1418 } 1419 1420 fib_info_cnt++; 1421 fi->fib_net = net; 1422 fi->fib_protocol = cfg->fc_protocol; 1423 fi->fib_scope = cfg->fc_scope; 1424 fi->fib_flags = cfg->fc_flags; 1425 fi->fib_priority = cfg->fc_priority; 1426 fi->fib_prefsrc = cfg->fc_prefsrc; 1427 fi->fib_type = cfg->fc_type; 1428 fi->fib_tb_id = cfg->fc_table; 1429 1430 fi->fib_nhs = nhs; 1431 if (nh) { 1432 if (!nexthop_get(nh)) { 1433 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1434 err = -EINVAL; 1435 } else { 1436 err = 0; 1437 fi->nh = nh; 1438 } 1439 } else { 1440 change_nexthops(fi) { 1441 nexthop_nh->nh_parent = fi; 1442 } endfor_nexthops(fi) 1443 1444 if (cfg->fc_mp) 1445 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1446 extack); 1447 else 1448 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1449 } 1450 1451 if (err != 0) 1452 goto failure; 1453 1454 if (fib_props[cfg->fc_type].error) { 1455 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1456 NL_SET_ERR_MSG(extack, 1457 "Gateway, device and multipath can not be specified for this route type"); 1458 goto err_inval; 1459 } 1460 goto link_it; 1461 } else { 1462 switch (cfg->fc_type) { 1463 case RTN_UNICAST: 1464 case RTN_LOCAL: 1465 case RTN_BROADCAST: 1466 case RTN_ANYCAST: 1467 case RTN_MULTICAST: 1468 break; 1469 default: 1470 NL_SET_ERR_MSG(extack, "Invalid route type"); 1471 goto err_inval; 1472 } 1473 } 1474 1475 if (cfg->fc_scope > RT_SCOPE_HOST) { 1476 NL_SET_ERR_MSG(extack, "Invalid scope"); 1477 goto err_inval; 1478 } 1479 1480 if (fi->nh) { 1481 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1482 if (err) 1483 goto failure; 1484 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1485 struct fib_nh *nh = fi->fib_nh; 1486 1487 /* Local address is added. */ 1488 if (nhs != 1) { 1489 NL_SET_ERR_MSG(extack, 1490 "Route with host scope can not have multiple nexthops"); 1491 goto err_inval; 1492 } 1493 if (nh->fib_nh_gw_family) { 1494 NL_SET_ERR_MSG(extack, 1495 "Route with host scope can not have a gateway"); 1496 goto err_inval; 1497 } 1498 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1499 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1500 err = -ENODEV; 1501 if (!nh->fib_nh_dev) 1502 goto failure; 1503 } else { 1504 int linkdown = 0; 1505 1506 change_nexthops(fi) { 1507 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1508 cfg->fc_table, cfg->fc_scope, 1509 extack); 1510 if (err != 0) 1511 goto failure; 1512 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1513 linkdown++; 1514 } endfor_nexthops(fi) 1515 if (linkdown == fi->fib_nhs) 1516 fi->fib_flags |= RTNH_F_LINKDOWN; 1517 } 1518 1519 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1520 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1521 goto err_inval; 1522 } 1523 1524 if (!fi->nh) { 1525 change_nexthops(fi) { 1526 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1527 fi->fib_scope); 1528 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1529 fi->fib_nh_is_v6 = true; 1530 } endfor_nexthops(fi) 1531 1532 fib_rebalance(fi); 1533 } 1534 1535 link_it: 1536 ofi = fib_find_info(fi); 1537 if (ofi) { 1538 fi->fib_dead = 1; 1539 free_fib_info(fi); 1540 ofi->fib_treeref++; 1541 return ofi; 1542 } 1543 1544 fi->fib_treeref++; 1545 refcount_set(&fi->fib_clntref, 1); 1546 spin_lock_bh(&fib_info_lock); 1547 hlist_add_head(&fi->fib_hash, 1548 &fib_info_hash[fib_info_hashfn(fi)]); 1549 if (fi->fib_prefsrc) { 1550 struct hlist_head *head; 1551 1552 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1553 hlist_add_head(&fi->fib_lhash, head); 1554 } 1555 if (fi->nh) { 1556 list_add(&fi->nh_list, &nh->fi_list); 1557 } else { 1558 change_nexthops(fi) { 1559 struct hlist_head *head; 1560 unsigned int hash; 1561 1562 if (!nexthop_nh->fib_nh_dev) 1563 continue; 1564 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex); 1565 head = &fib_info_devhash[hash]; 1566 hlist_add_head(&nexthop_nh->nh_hash, head); 1567 } endfor_nexthops(fi) 1568 } 1569 spin_unlock_bh(&fib_info_lock); 1570 return fi; 1571 1572 err_inval: 1573 err = -EINVAL; 1574 1575 failure: 1576 if (fi) { 1577 fi->fib_dead = 1; 1578 free_fib_info(fi); 1579 } 1580 1581 return ERR_PTR(err); 1582 } 1583 1584 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1585 u8 rt_family, unsigned char *flags, bool skip_oif) 1586 { 1587 if (nhc->nhc_flags & RTNH_F_DEAD) 1588 *flags |= RTNH_F_DEAD; 1589 1590 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1591 *flags |= RTNH_F_LINKDOWN; 1592 1593 rcu_read_lock(); 1594 switch (nhc->nhc_family) { 1595 case AF_INET: 1596 if (ip_ignore_linkdown(nhc->nhc_dev)) 1597 *flags |= RTNH_F_DEAD; 1598 break; 1599 case AF_INET6: 1600 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1601 *flags |= RTNH_F_DEAD; 1602 break; 1603 } 1604 rcu_read_unlock(); 1605 } 1606 1607 switch (nhc->nhc_gw_family) { 1608 case AF_INET: 1609 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1610 goto nla_put_failure; 1611 break; 1612 case AF_INET6: 1613 /* if gateway family does not match nexthop family 1614 * gateway is encoded as RTA_VIA 1615 */ 1616 if (rt_family != nhc->nhc_gw_family) { 1617 int alen = sizeof(struct in6_addr); 1618 struct nlattr *nla; 1619 struct rtvia *via; 1620 1621 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1622 if (!nla) 1623 goto nla_put_failure; 1624 1625 via = nla_data(nla); 1626 via->rtvia_family = AF_INET6; 1627 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1628 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1629 &nhc->nhc_gw.ipv6) < 0) { 1630 goto nla_put_failure; 1631 } 1632 break; 1633 } 1634 1635 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK); 1636 if (nhc->nhc_flags & RTNH_F_OFFLOAD) 1637 *flags |= RTNH_F_OFFLOAD; 1638 1639 if (!skip_oif && nhc->nhc_dev && 1640 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1641 goto nla_put_failure; 1642 1643 if (nhc->nhc_lwtstate && 1644 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1645 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1646 goto nla_put_failure; 1647 1648 return 0; 1649 1650 nla_put_failure: 1651 return -EMSGSIZE; 1652 } 1653 EXPORT_SYMBOL_GPL(fib_nexthop_info); 1654 1655 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1656 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1657 int nh_weight, u8 rt_family) 1658 { 1659 const struct net_device *dev = nhc->nhc_dev; 1660 struct rtnexthop *rtnh; 1661 unsigned char flags = 0; 1662 1663 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1664 if (!rtnh) 1665 goto nla_put_failure; 1666 1667 rtnh->rtnh_hops = nh_weight - 1; 1668 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1669 1670 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1671 goto nla_put_failure; 1672 1673 rtnh->rtnh_flags = flags; 1674 1675 /* length of rtnetlink header + attributes */ 1676 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1677 1678 return 0; 1679 1680 nla_put_failure: 1681 return -EMSGSIZE; 1682 } 1683 EXPORT_SYMBOL_GPL(fib_add_nexthop); 1684 #endif 1685 1686 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1687 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1688 { 1689 struct nlattr *mp; 1690 1691 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1692 if (!mp) 1693 goto nla_put_failure; 1694 1695 if (unlikely(fi->nh)) { 1696 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1697 goto nla_put_failure; 1698 goto mp_end; 1699 } 1700 1701 for_nexthops(fi) { 1702 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1703 AF_INET) < 0) 1704 goto nla_put_failure; 1705 #ifdef CONFIG_IP_ROUTE_CLASSID 1706 if (nh->nh_tclassid && 1707 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1708 goto nla_put_failure; 1709 #endif 1710 } endfor_nexthops(fi); 1711 1712 mp_end: 1713 nla_nest_end(skb, mp); 1714 1715 return 0; 1716 1717 nla_put_failure: 1718 return -EMSGSIZE; 1719 } 1720 #else 1721 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1722 { 1723 return 0; 1724 } 1725 #endif 1726 1727 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1728 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1729 struct fib_info *fi, unsigned int flags) 1730 { 1731 unsigned int nhs = fib_info_num_path(fi); 1732 struct nlmsghdr *nlh; 1733 struct rtmsg *rtm; 1734 1735 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1736 if (!nlh) 1737 return -EMSGSIZE; 1738 1739 rtm = nlmsg_data(nlh); 1740 rtm->rtm_family = AF_INET; 1741 rtm->rtm_dst_len = dst_len; 1742 rtm->rtm_src_len = 0; 1743 rtm->rtm_tos = tos; 1744 if (tb_id < 256) 1745 rtm->rtm_table = tb_id; 1746 else 1747 rtm->rtm_table = RT_TABLE_COMPAT; 1748 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1749 goto nla_put_failure; 1750 rtm->rtm_type = type; 1751 rtm->rtm_flags = fi->fib_flags; 1752 rtm->rtm_scope = fi->fib_scope; 1753 rtm->rtm_protocol = fi->fib_protocol; 1754 1755 if (rtm->rtm_dst_len && 1756 nla_put_in_addr(skb, RTA_DST, dst)) 1757 goto nla_put_failure; 1758 if (fi->fib_priority && 1759 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1760 goto nla_put_failure; 1761 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1762 goto nla_put_failure; 1763 1764 if (fi->fib_prefsrc && 1765 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1766 goto nla_put_failure; 1767 1768 if (fi->nh) { 1769 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1770 goto nla_put_failure; 1771 if (nexthop_is_blackhole(fi->nh)) 1772 rtm->rtm_type = RTN_BLACKHOLE; 1773 } 1774 1775 if (nhs == 1) { 1776 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1777 unsigned char flags = 0; 1778 1779 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1780 goto nla_put_failure; 1781 1782 rtm->rtm_flags = flags; 1783 #ifdef CONFIG_IP_ROUTE_CLASSID 1784 if (nhc->nhc_family == AF_INET) { 1785 struct fib_nh *nh; 1786 1787 nh = container_of(nhc, struct fib_nh, nh_common); 1788 if (nh->nh_tclassid && 1789 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1790 goto nla_put_failure; 1791 } 1792 #endif 1793 } else { 1794 if (fib_add_multipath(skb, fi) < 0) 1795 goto nla_put_failure; 1796 } 1797 1798 nlmsg_end(skb, nlh); 1799 return 0; 1800 1801 nla_put_failure: 1802 nlmsg_cancel(skb, nlh); 1803 return -EMSGSIZE; 1804 } 1805 1806 /* 1807 * Update FIB if: 1808 * - local address disappeared -> we must delete all the entries 1809 * referring to it. 1810 * - device went down -> we must shutdown all nexthops going via it. 1811 */ 1812 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1813 { 1814 int ret = 0; 1815 unsigned int hash = fib_laddr_hashfn(local); 1816 struct hlist_head *head = &fib_info_laddrhash[hash]; 1817 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1818 struct net *net = dev_net(dev); 1819 struct fib_info *fi; 1820 1821 if (!fib_info_laddrhash || local == 0) 1822 return 0; 1823 1824 hlist_for_each_entry(fi, head, fib_lhash) { 1825 if (!net_eq(fi->fib_net, net) || 1826 fi->fib_tb_id != tb_id) 1827 continue; 1828 if (fi->fib_prefsrc == local) { 1829 fi->fib_flags |= RTNH_F_DEAD; 1830 ret++; 1831 } 1832 } 1833 return ret; 1834 } 1835 1836 static int call_fib_nh_notifiers(struct fib_nh *nh, 1837 enum fib_event_type event_type) 1838 { 1839 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1840 struct fib_nh_notifier_info info = { 1841 .fib_nh = nh, 1842 }; 1843 1844 switch (event_type) { 1845 case FIB_EVENT_NH_ADD: 1846 if (nh->fib_nh_flags & RTNH_F_DEAD) 1847 break; 1848 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1849 break; 1850 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1851 &info.info); 1852 case FIB_EVENT_NH_DEL: 1853 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1854 (nh->fib_nh_flags & RTNH_F_DEAD)) 1855 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1856 event_type, &info.info); 1857 default: 1858 break; 1859 } 1860 1861 return NOTIFY_DONE; 1862 } 1863 1864 /* Update the PMTU of exceptions when: 1865 * - the new MTU of the first hop becomes smaller than the PMTU 1866 * - the old MTU was the same as the PMTU, and it limited discovery of 1867 * larger MTUs on the path. With that limit raised, we can now 1868 * discover larger MTUs 1869 * A special case is locked exceptions, for which the PMTU is smaller 1870 * than the minimal accepted PMTU: 1871 * - if the new MTU is greater than the PMTU, don't make any change 1872 * - otherwise, unlock and set PMTU 1873 */ 1874 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1875 { 1876 struct fnhe_hash_bucket *bucket; 1877 int i; 1878 1879 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1880 if (!bucket) 1881 return; 1882 1883 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1884 struct fib_nh_exception *fnhe; 1885 1886 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1887 fnhe; 1888 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1889 if (fnhe->fnhe_mtu_locked) { 1890 if (new <= fnhe->fnhe_pmtu) { 1891 fnhe->fnhe_pmtu = new; 1892 fnhe->fnhe_mtu_locked = false; 1893 } 1894 } else if (new < fnhe->fnhe_pmtu || 1895 orig == fnhe->fnhe_pmtu) { 1896 fnhe->fnhe_pmtu = new; 1897 } 1898 } 1899 } 1900 } 1901 1902 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1903 { 1904 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1905 struct hlist_head *head = &fib_info_devhash[hash]; 1906 struct fib_nh *nh; 1907 1908 hlist_for_each_entry(nh, head, nh_hash) { 1909 if (nh->fib_nh_dev == dev) 1910 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1911 } 1912 } 1913 1914 /* Event force Flags Description 1915 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1916 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1917 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1918 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1919 * 1920 * only used when fib_nh is built into fib_info 1921 */ 1922 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1923 { 1924 int ret = 0; 1925 int scope = RT_SCOPE_NOWHERE; 1926 struct fib_info *prev_fi = NULL; 1927 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1928 struct hlist_head *head = &fib_info_devhash[hash]; 1929 struct fib_nh *nh; 1930 1931 if (force) 1932 scope = -1; 1933 1934 hlist_for_each_entry(nh, head, nh_hash) { 1935 struct fib_info *fi = nh->nh_parent; 1936 int dead; 1937 1938 BUG_ON(!fi->fib_nhs); 1939 if (nh->fib_nh_dev != dev || fi == prev_fi) 1940 continue; 1941 prev_fi = fi; 1942 dead = 0; 1943 change_nexthops(fi) { 1944 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 1945 dead++; 1946 else if (nexthop_nh->fib_nh_dev == dev && 1947 nexthop_nh->fib_nh_scope != scope) { 1948 switch (event) { 1949 case NETDEV_DOWN: 1950 case NETDEV_UNREGISTER: 1951 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 1952 /* fall through */ 1953 case NETDEV_CHANGE: 1954 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1955 break; 1956 } 1957 call_fib_nh_notifiers(nexthop_nh, 1958 FIB_EVENT_NH_DEL); 1959 dead++; 1960 } 1961 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1962 if (event == NETDEV_UNREGISTER && 1963 nexthop_nh->fib_nh_dev == dev) { 1964 dead = fi->fib_nhs; 1965 break; 1966 } 1967 #endif 1968 } endfor_nexthops(fi) 1969 if (dead == fi->fib_nhs) { 1970 switch (event) { 1971 case NETDEV_DOWN: 1972 case NETDEV_UNREGISTER: 1973 fi->fib_flags |= RTNH_F_DEAD; 1974 /* fall through */ 1975 case NETDEV_CHANGE: 1976 fi->fib_flags |= RTNH_F_LINKDOWN; 1977 break; 1978 } 1979 ret++; 1980 } 1981 1982 fib_rebalance(fi); 1983 } 1984 1985 return ret; 1986 } 1987 1988 /* Must be invoked inside of an RCU protected region. */ 1989 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1990 { 1991 struct fib_info *fi = NULL, *last_resort = NULL; 1992 struct hlist_head *fa_head = res->fa_head; 1993 struct fib_table *tb = res->table; 1994 u8 slen = 32 - res->prefixlen; 1995 int order = -1, last_idx = -1; 1996 struct fib_alias *fa, *fa1 = NULL; 1997 u32 last_prio = res->fi->fib_priority; 1998 u8 last_tos = 0; 1999 2000 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2001 struct fib_info *next_fi = fa->fa_info; 2002 struct fib_nh *nh; 2003 2004 if (fa->fa_slen != slen) 2005 continue; 2006 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 2007 continue; 2008 if (fa->tb_id != tb->tb_id) 2009 continue; 2010 if (next_fi->fib_priority > last_prio && 2011 fa->fa_tos == last_tos) { 2012 if (last_tos) 2013 continue; 2014 break; 2015 } 2016 if (next_fi->fib_flags & RTNH_F_DEAD) 2017 continue; 2018 last_tos = fa->fa_tos; 2019 last_prio = next_fi->fib_priority; 2020 2021 if (next_fi->fib_scope != res->scope || 2022 fa->fa_type != RTN_UNICAST) 2023 continue; 2024 2025 nh = fib_info_nh(next_fi, 0); 2026 if (!nh->fib_nh_gw4 || nh->fib_nh_scope != RT_SCOPE_LINK) 2027 continue; 2028 2029 fib_alias_accessed(fa); 2030 2031 if (!fi) { 2032 if (next_fi != res->fi) 2033 break; 2034 fa1 = fa; 2035 } else if (!fib_detect_death(fi, order, &last_resort, 2036 &last_idx, fa1->fa_default)) { 2037 fib_result_assign(res, fi); 2038 fa1->fa_default = order; 2039 goto out; 2040 } 2041 fi = next_fi; 2042 order++; 2043 } 2044 2045 if (order <= 0 || !fi) { 2046 if (fa1) 2047 fa1->fa_default = -1; 2048 goto out; 2049 } 2050 2051 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2052 fa1->fa_default)) { 2053 fib_result_assign(res, fi); 2054 fa1->fa_default = order; 2055 goto out; 2056 } 2057 2058 if (last_idx >= 0) 2059 fib_result_assign(res, last_resort); 2060 fa1->fa_default = last_idx; 2061 out: 2062 return; 2063 } 2064 2065 /* 2066 * Dead device goes up. We wake up dead nexthops. 2067 * It takes sense only on multipath routes. 2068 * 2069 * only used when fib_nh is built into fib_info 2070 */ 2071 int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2072 { 2073 struct fib_info *prev_fi; 2074 unsigned int hash; 2075 struct hlist_head *head; 2076 struct fib_nh *nh; 2077 int ret; 2078 2079 if (!(dev->flags & IFF_UP)) 2080 return 0; 2081 2082 if (nh_flags & RTNH_F_DEAD) { 2083 unsigned int flags = dev_get_flags(dev); 2084 2085 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2086 nh_flags |= RTNH_F_LINKDOWN; 2087 } 2088 2089 prev_fi = NULL; 2090 hash = fib_devindex_hashfn(dev->ifindex); 2091 head = &fib_info_devhash[hash]; 2092 ret = 0; 2093 2094 hlist_for_each_entry(nh, head, nh_hash) { 2095 struct fib_info *fi = nh->nh_parent; 2096 int alive; 2097 2098 BUG_ON(!fi->fib_nhs); 2099 if (nh->fib_nh_dev != dev || fi == prev_fi) 2100 continue; 2101 2102 prev_fi = fi; 2103 alive = 0; 2104 change_nexthops(fi) { 2105 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2106 alive++; 2107 continue; 2108 } 2109 if (!nexthop_nh->fib_nh_dev || 2110 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2111 continue; 2112 if (nexthop_nh->fib_nh_dev != dev || 2113 !__in_dev_get_rtnl(dev)) 2114 continue; 2115 alive++; 2116 nexthop_nh->fib_nh_flags &= ~nh_flags; 2117 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2118 } endfor_nexthops(fi) 2119 2120 if (alive > 0) { 2121 fi->fib_flags &= ~nh_flags; 2122 ret++; 2123 } 2124 2125 fib_rebalance(fi); 2126 } 2127 2128 return ret; 2129 } 2130 2131 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2132 static bool fib_good_nh(const struct fib_nh *nh) 2133 { 2134 int state = NUD_REACHABLE; 2135 2136 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2137 struct neighbour *n; 2138 2139 rcu_read_lock_bh(); 2140 2141 if (likely(nh->fib_nh_gw_family == AF_INET)) 2142 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2143 (__force u32)nh->fib_nh_gw4); 2144 else if (nh->fib_nh_gw_family == AF_INET6) 2145 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2146 &nh->fib_nh_gw6); 2147 else 2148 n = NULL; 2149 if (n) 2150 state = n->nud_state; 2151 2152 rcu_read_unlock_bh(); 2153 } 2154 2155 return !!(state & NUD_VALID); 2156 } 2157 2158 void fib_select_multipath(struct fib_result *res, int hash) 2159 { 2160 struct fib_info *fi = res->fi; 2161 struct net *net = fi->fib_net; 2162 bool first = false; 2163 2164 if (unlikely(res->fi->nh)) { 2165 nexthop_path_fib_result(res, hash); 2166 return; 2167 } 2168 2169 change_nexthops(fi) { 2170 if (net->ipv4.sysctl_fib_multipath_use_neigh) { 2171 if (!fib_good_nh(nexthop_nh)) 2172 continue; 2173 if (!first) { 2174 res->nh_sel = nhsel; 2175 res->nhc = &nexthop_nh->nh_common; 2176 first = true; 2177 } 2178 } 2179 2180 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2181 continue; 2182 2183 res->nh_sel = nhsel; 2184 res->nhc = &nexthop_nh->nh_common; 2185 return; 2186 } endfor_nexthops(fi); 2187 } 2188 #endif 2189 2190 void fib_select_path(struct net *net, struct fib_result *res, 2191 struct flowi4 *fl4, const struct sk_buff *skb) 2192 { 2193 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 2194 goto check_saddr; 2195 2196 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2197 if (fib_info_num_path(res->fi) > 1) { 2198 int h = fib_multipath_hash(net, fl4, skb, NULL); 2199 2200 fib_select_multipath(res, h); 2201 } 2202 else 2203 #endif 2204 if (!res->prefixlen && 2205 res->table->tb_num_default > 1 && 2206 res->type == RTN_UNICAST) 2207 fib_select_default(fl4, res); 2208 2209 check_saddr: 2210 if (!fl4->saddr) 2211 fl4->saddr = fib_result_prefsrc(net, res); 2212 } 2213