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#include <linux/hash.h> 33#include <linux/nospec.h> 34 35#include <net/arp.h> 36#include <net/ip.h> 37#include <net/protocol.h> 38#include <net/route.h> 39#include <net/tcp.h> 40#include <net/sock.h> 41#include <net/ip_fib.h> 42#include <net/ip6_fib.h> 43#include <net/nexthop.h> 44#include <net/netlink.h> 45#include <net/rtnh.h> 46#include <net/lwtunnel.h> 47#include <net/fib_notifier.h> 48#include <net/addrconf.h> 49 50#include "fib_lookup.h" 51 52static DEFINE_SPINLOCK(fib_info_lock); 53static struct hlist_head *fib_info_hash; 54static struct hlist_head *fib_info_laddrhash; 55static unsigned int fib_info_hash_size; 56static unsigned int fib_info_cnt; 57 58#define DEVINDEX_HASHBITS 8 59#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 60static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 61 62/* for_nexthops and change_nexthops only used when nexthop object 63 * is not set in a fib_info. The logic within can reference fib_nh. 64 */ 65#ifdef CONFIG_IP_ROUTE_MULTIPATH 66 67#define for_nexthops(fi) { \ 68 int nhsel; const struct fib_nh *nh; \ 69 for (nhsel = 0, nh = (fi)->fib_nh; \ 70 nhsel < fib_info_num_path((fi)); \ 71 nh++, nhsel++) 72 73#define change_nexthops(fi) { \ 74 int nhsel; struct fib_nh *nexthop_nh; \ 75 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 76 nhsel < fib_info_num_path((fi)); \ 77 nexthop_nh++, nhsel++) 78 79#else /* CONFIG_IP_ROUTE_MULTIPATH */ 80 81/* Hope, that gcc will optimize it to get rid of dummy loop */ 82 83#define for_nexthops(fi) { \ 84 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 85 for (nhsel = 0; nhsel < 1; nhsel++) 86 87#define change_nexthops(fi) { \ 88 int nhsel; \ 89 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 90 for (nhsel = 0; nhsel < 1; nhsel++) 91 92#endif /* CONFIG_IP_ROUTE_MULTIPATH */ 93 94#define endfor_nexthops(fi) } 95 96 97const struct fib_prop fib_props[RTN_MAX + 1] = { 98 [RTN_UNSPEC] = { 99 .error = 0, 100 .scope = RT_SCOPE_NOWHERE, 101 }, 102 [RTN_UNICAST] = { 103 .error = 0, 104 .scope = RT_SCOPE_UNIVERSE, 105 }, 106 [RTN_LOCAL] = { 107 .error = 0, 108 .scope = RT_SCOPE_HOST, 109 }, 110 [RTN_BROADCAST] = { 111 .error = 0, 112 .scope = RT_SCOPE_LINK, 113 }, 114 [RTN_ANYCAST] = { 115 .error = 0, 116 .scope = RT_SCOPE_LINK, 117 }, 118 [RTN_MULTICAST] = { 119 .error = 0, 120 .scope = RT_SCOPE_UNIVERSE, 121 }, 122 [RTN_BLACKHOLE] = { 123 .error = -EINVAL, 124 .scope = RT_SCOPE_UNIVERSE, 125 }, 126 [RTN_UNREACHABLE] = { 127 .error = -EHOSTUNREACH, 128 .scope = RT_SCOPE_UNIVERSE, 129 }, 130 [RTN_PROHIBIT] = { 131 .error = -EACCES, 132 .scope = RT_SCOPE_UNIVERSE, 133 }, 134 [RTN_THROW] = { 135 .error = -EAGAIN, 136 .scope = RT_SCOPE_UNIVERSE, 137 }, 138 [RTN_NAT] = { 139 .error = -EINVAL, 140 .scope = RT_SCOPE_NOWHERE, 141 }, 142 [RTN_XRESOLVE] = { 143 .error = -EINVAL, 144 .scope = RT_SCOPE_NOWHERE, 145 }, 146}; 147 148static void rt_fibinfo_free(struct rtable __rcu **rtp) 149{ 150 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 151 152 if (!rt) 153 return; 154 155 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 156 * because we waited an RCU grace period before calling 157 * free_fib_info_rcu() 158 */ 159 160 dst_dev_put(&rt->dst); 161 dst_release_immediate(&rt->dst); 162} 163 164static void free_nh_exceptions(struct fib_nh_common *nhc) 165{ 166 struct fnhe_hash_bucket *hash; 167 int i; 168 169 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); 170 if (!hash) 171 return; 172 for (i = 0; i < FNHE_HASH_SIZE; i++) { 173 struct fib_nh_exception *fnhe; 174 175 fnhe = rcu_dereference_protected(hash[i].chain, 1); 176 while (fnhe) { 177 struct fib_nh_exception *next; 178 179 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 180 181 rt_fibinfo_free(&fnhe->fnhe_rth_input); 182 rt_fibinfo_free(&fnhe->fnhe_rth_output); 183 184 kfree(fnhe); 185 186 fnhe = next; 187 } 188 } 189 kfree(hash); 190} 191 192static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 193{ 194 int cpu; 195 196 if (!rtp) 197 return; 198 199 for_each_possible_cpu(cpu) { 200 struct rtable *rt; 201 202 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 203 if (rt) { 204 dst_dev_put(&rt->dst); 205 dst_release_immediate(&rt->dst); 206 } 207 } 208 free_percpu(rtp); 209} 210 211void fib_nh_common_release(struct fib_nh_common *nhc) 212{ 213 if (nhc->nhc_dev) 214 dev_put(nhc->nhc_dev); 215 216 lwtstate_put(nhc->nhc_lwtstate); 217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 218 rt_fibinfo_free(&nhc->nhc_rth_input); 219 free_nh_exceptions(nhc); 220} 221EXPORT_SYMBOL_GPL(fib_nh_common_release); 222 223void fib_nh_release(struct net *net, struct fib_nh *fib_nh) 224{ 225#ifdef CONFIG_IP_ROUTE_CLASSID 226 if (fib_nh->nh_tclassid) 227 atomic_dec(&net->ipv4.fib_num_tclassid_users); 228#endif 229 fib_nh_common_release(&fib_nh->nh_common); 230} 231 232/* Release a nexthop info record */ 233static void free_fib_info_rcu(struct rcu_head *head) 234{ 235 struct fib_info *fi = container_of(head, struct fib_info, rcu); 236 237 if (fi->nh) { 238 nexthop_put(fi->nh); 239 } else { 240 change_nexthops(fi) { 241 fib_nh_release(fi->fib_net, nexthop_nh); 242 } endfor_nexthops(fi); 243 } 244 245 ip_fib_metrics_put(fi->fib_metrics); 246 247 kfree(fi); 248} 249 250void free_fib_info(struct fib_info *fi) 251{ 252 if (fi->fib_dead == 0) { 253 pr_warn("Freeing alive fib_info %p\n", fi); 254 return; 255 } 256 257 call_rcu(&fi->rcu, free_fib_info_rcu); 258} 259EXPORT_SYMBOL_GPL(free_fib_info); 260 261void fib_release_info(struct fib_info *fi) 262{ 263 spin_lock_bh(&fib_info_lock); 264 if (fi && --fi->fib_treeref == 0) { 265 hlist_del(&fi->fib_hash); 266 267 /* Paired with READ_ONCE() in fib_create_info(). */ 268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1); 269 270 if (fi->fib_prefsrc) 271 hlist_del(&fi->fib_lhash); 272 if (fi->nh) { 273 list_del(&fi->nh_list); 274 } else { 275 change_nexthops(fi) { 276 if (!nexthop_nh->fib_nh_dev) 277 continue; 278 hlist_del(&nexthop_nh->nh_hash); 279 } endfor_nexthops(fi) 280 } 281 /* Paired with READ_ONCE() from fib_table_lookup() */ 282 WRITE_ONCE(fi->fib_dead, 1); 283 fib_info_put(fi); 284 } 285 spin_unlock_bh(&fib_info_lock); 286} 287 288static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 289{ 290 const struct fib_nh *onh; 291 292 if (fi->nh || ofi->nh) 293 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; 294 295 if (ofi->fib_nhs == 0) 296 return 0; 297 298 for_nexthops(fi) { 299 onh = fib_info_nh(ofi, nhsel); 300 301 if (nh->fib_nh_oif != onh->fib_nh_oif || 302 nh->fib_nh_gw_family != onh->fib_nh_gw_family || 303 nh->fib_nh_scope != onh->fib_nh_scope || 304#ifdef CONFIG_IP_ROUTE_MULTIPATH 305 nh->fib_nh_weight != onh->fib_nh_weight || 306#endif 307#ifdef CONFIG_IP_ROUTE_CLASSID 308 nh->nh_tclassid != onh->nh_tclassid || 309#endif 310 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || 311 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) 312 return -1; 313 314 if (nh->fib_nh_gw_family == AF_INET && 315 nh->fib_nh_gw4 != onh->fib_nh_gw4) 316 return -1; 317 318 if (nh->fib_nh_gw_family == AF_INET6 && 319 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) 320 return -1; 321 } endfor_nexthops(fi); 322 return 0; 323} 324 325static inline unsigned int fib_devindex_hashfn(unsigned int val) 326{ 327 return hash_32(val, DEVINDEX_HASHBITS); 328} 329 330static struct hlist_head * 331fib_info_devhash_bucket(const struct net_device *dev) 332{ 333 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex; 334 335 return &fib_info_devhash[fib_devindex_hashfn(val)]; 336} 337 338static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, 339 u32 prefsrc, u32 priority) 340{ 341 unsigned int val = init_val; 342 343 val ^= (protocol << 8) | scope; 344 val ^= prefsrc; 345 val ^= priority; 346 347 return val; 348} 349 350static unsigned int fib_info_hashfn_result(unsigned int val) 351{ 352 unsigned int mask = (fib_info_hash_size - 1); 353 354 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 355} 356 357static inline unsigned int fib_info_hashfn(struct fib_info *fi) 358{ 359 unsigned int val; 360 361 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, 362 fi->fib_scope, (__force u32)fi->fib_prefsrc, 363 fi->fib_priority); 364 365 if (fi->nh) { 366 val ^= fib_devindex_hashfn(fi->nh->id); 367 } else { 368 for_nexthops(fi) { 369 val ^= fib_devindex_hashfn(nh->fib_nh_oif); 370 } endfor_nexthops(fi) 371 } 372 373 return fib_info_hashfn_result(val); 374} 375 376/* no metrics, only nexthop id */ 377static struct fib_info *fib_find_info_nh(struct net *net, 378 const struct fib_config *cfg) 379{ 380 struct hlist_head *head; 381 struct fib_info *fi; 382 unsigned int hash; 383 384 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id), 385 cfg->fc_protocol, cfg->fc_scope, 386 (__force u32)cfg->fc_prefsrc, 387 cfg->fc_priority); 388 hash = fib_info_hashfn_result(hash); 389 head = &fib_info_hash[hash]; 390 391 hlist_for_each_entry(fi, head, fib_hash) { 392 if (!net_eq(fi->fib_net, net)) 393 continue; 394 if (!fi->nh || fi->nh->id != cfg->fc_nh_id) 395 continue; 396 if (cfg->fc_protocol == fi->fib_protocol && 397 cfg->fc_scope == fi->fib_scope && 398 cfg->fc_prefsrc == fi->fib_prefsrc && 399 cfg->fc_priority == fi->fib_priority && 400 cfg->fc_type == fi->fib_type && 401 cfg->fc_table == fi->fib_tb_id && 402 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) 403 return fi; 404 } 405 406 return NULL; 407} 408 409static struct fib_info *fib_find_info(struct fib_info *nfi) 410{ 411 struct hlist_head *head; 412 struct fib_info *fi; 413 unsigned int hash; 414 415 hash = fib_info_hashfn(nfi); 416 head = &fib_info_hash[hash]; 417 418 hlist_for_each_entry(fi, head, fib_hash) { 419 if (!net_eq(fi->fib_net, nfi->fib_net)) 420 continue; 421 if (fi->fib_nhs != nfi->fib_nhs) 422 continue; 423 if (nfi->fib_protocol == fi->fib_protocol && 424 nfi->fib_scope == fi->fib_scope && 425 nfi->fib_prefsrc == fi->fib_prefsrc && 426 nfi->fib_priority == fi->fib_priority && 427 nfi->fib_type == fi->fib_type && 428 nfi->fib_tb_id == fi->fib_tb_id && 429 memcmp(nfi->fib_metrics, fi->fib_metrics, 430 sizeof(u32) * RTAX_MAX) == 0 && 431 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 432 nh_comp(fi, nfi) == 0) 433 return fi; 434 } 435 436 return NULL; 437} 438 439/* Check, that the gateway is already configured. 440 * Used only by redirect accept routine. 441 */ 442int ip_fib_check_default(__be32 gw, struct net_device *dev) 443{ 444 struct hlist_head *head; 445 struct fib_nh *nh; 446 447 spin_lock(&fib_info_lock); 448 449 head = fib_info_devhash_bucket(dev); 450 451 hlist_for_each_entry(nh, head, nh_hash) { 452 if (nh->fib_nh_dev == dev && 453 nh->fib_nh_gw4 == gw && 454 !(nh->fib_nh_flags & RTNH_F_DEAD)) { 455 spin_unlock(&fib_info_lock); 456 return 0; 457 } 458 } 459 460 spin_unlock(&fib_info_lock); 461 462 return -1; 463} 464 465static inline size_t fib_nlmsg_size(struct fib_info *fi) 466{ 467 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 468 + nla_total_size(4) /* RTA_TABLE */ 469 + nla_total_size(4) /* RTA_DST */ 470 + nla_total_size(4) /* RTA_PRIORITY */ 471 + nla_total_size(4) /* RTA_PREFSRC */ 472 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 473 unsigned int nhs = fib_info_num_path(fi); 474 475 /* space for nested metrics */ 476 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 477 478 if (fi->nh) 479 payload += nla_total_size(4); /* RTA_NH_ID */ 480 481 if (nhs) { 482 size_t nh_encapsize = 0; 483 /* Also handles the special case nhs == 1 */ 484 485 /* each nexthop is packed in an attribute */ 486 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 487 unsigned int i; 488 489 /* may contain flow and gateway attribute */ 490 nhsize += 2 * nla_total_size(4); 491 492 /* grab encap info */ 493 for (i = 0; i < fib_info_num_path(fi); i++) { 494 struct fib_nh_common *nhc = fib_info_nhc(fi, i); 495 496 if (nhc->nhc_lwtstate) { 497 /* RTA_ENCAP_TYPE */ 498 nh_encapsize += lwtunnel_get_encap_size( 499 nhc->nhc_lwtstate); 500 /* RTA_ENCAP */ 501 nh_encapsize += nla_total_size(2); 502 } 503 } 504 505 /* all nexthops are packed in a nested attribute */ 506 payload += nla_total_size((nhs * nhsize) + nh_encapsize); 507 508 } 509 510 return payload; 511} 512 513void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 514 int dst_len, u32 tb_id, const struct nl_info *info, 515 unsigned int nlm_flags) 516{ 517 struct fib_rt_info fri; 518 struct sk_buff *skb; 519 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 520 int err = -ENOBUFS; 521 522 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 523 if (!skb) 524 goto errout; 525 526 fri.fi = fa->fa_info; 527 fri.tb_id = tb_id; 528 fri.dst = key; 529 fri.dst_len = dst_len; 530 fri.tos = fa->fa_tos; 531 fri.type = fa->fa_type; 532 fri.offload = fa->offload; 533 fri.trap = fa->trap; 534 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags); 535 if (err < 0) { 536 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 537 WARN_ON(err == -EMSGSIZE); 538 kfree_skb(skb); 539 goto errout; 540 } 541 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 542 info->nlh, GFP_KERNEL); 543 return; 544errout: 545 if (err < 0) 546 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 547} 548 549static int fib_detect_death(struct fib_info *fi, int order, 550 struct fib_info **last_resort, int *last_idx, 551 int dflt) 552{ 553 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 554 struct neighbour *n; 555 int state = NUD_NONE; 556 557 if (likely(nhc->nhc_gw_family == AF_INET)) 558 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); 559 else if (nhc->nhc_gw_family == AF_INET6) 560 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, 561 nhc->nhc_dev); 562 else 563 n = NULL; 564 565 if (n) { 566 state = n->nud_state; 567 neigh_release(n); 568 } else { 569 return 0; 570 } 571 if (state == NUD_REACHABLE) 572 return 0; 573 if ((state & NUD_VALID) && order != dflt) 574 return 0; 575 if ((state & NUD_VALID) || 576 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 577 *last_resort = fi; 578 *last_idx = order; 579 } 580 return 1; 581} 582 583int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, 584 struct nlattr *encap, u16 encap_type, 585 void *cfg, gfp_t gfp_flags, 586 struct netlink_ext_ack *extack) 587{ 588 int err; 589 590 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, 591 gfp_flags); 592 if (!nhc->nhc_pcpu_rth_output) 593 return -ENOMEM; 594 595 if (encap) { 596 struct lwtunnel_state *lwtstate; 597 598 if (encap_type == LWTUNNEL_ENCAP_NONE) { 599 NL_SET_ERR_MSG(extack, "LWT encap type not specified"); 600 err = -EINVAL; 601 goto lwt_failure; 602 } 603 err = lwtunnel_build_state(net, encap_type, encap, 604 nhc->nhc_family, cfg, &lwtstate, 605 extack); 606 if (err) 607 goto lwt_failure; 608 609 nhc->nhc_lwtstate = lwtstate_get(lwtstate); 610 } 611 612 return 0; 613 614lwt_failure: 615 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); 616 nhc->nhc_pcpu_rth_output = NULL; 617 return err; 618} 619EXPORT_SYMBOL_GPL(fib_nh_common_init); 620 621int fib_nh_init(struct net *net, struct fib_nh *nh, 622 struct fib_config *cfg, int nh_weight, 623 struct netlink_ext_ack *extack) 624{ 625 int err; 626 627 nh->fib_nh_family = AF_INET; 628 629 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, 630 cfg->fc_encap_type, cfg, GFP_KERNEL, extack); 631 if (err) 632 return err; 633 634 nh->fib_nh_oif = cfg->fc_oif; 635 nh->fib_nh_gw_family = cfg->fc_gw_family; 636 if (cfg->fc_gw_family == AF_INET) 637 nh->fib_nh_gw4 = cfg->fc_gw4; 638 else if (cfg->fc_gw_family == AF_INET6) 639 nh->fib_nh_gw6 = cfg->fc_gw6; 640 641 nh->fib_nh_flags = cfg->fc_flags; 642 643#ifdef CONFIG_IP_ROUTE_CLASSID 644 nh->nh_tclassid = cfg->fc_flow; 645 if (nh->nh_tclassid) 646 atomic_inc(&net->ipv4.fib_num_tclassid_users); 647#endif 648#ifdef CONFIG_IP_ROUTE_MULTIPATH 649 nh->fib_nh_weight = nh_weight; 650#endif 651 return 0; 652} 653 654#ifdef CONFIG_IP_ROUTE_MULTIPATH 655 656static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 657 struct netlink_ext_ack *extack) 658{ 659 int nhs = 0; 660 661 while (rtnh_ok(rtnh, remaining)) { 662 nhs++; 663 rtnh = rtnh_next(rtnh, &remaining); 664 } 665 666 /* leftover implies invalid nexthop configuration, discard it */ 667 if (remaining > 0) { 668 NL_SET_ERR_MSG(extack, 669 "Invalid nexthop configuration - extra data after nexthops"); 670 nhs = 0; 671 } 672 673 return nhs; 674} 675 676static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, 677 struct netlink_ext_ack *extack) 678{ 679 if (nla_len(nla) < sizeof(*gw)) { 680 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); 681 return -EINVAL; 682 } 683 684 *gw = nla_get_in_addr(nla); 685 686 return 0; 687} 688 689/* only called when fib_nh is integrated into fib_info */ 690static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 691 int remaining, struct fib_config *cfg, 692 struct netlink_ext_ack *extack) 693{ 694 struct net *net = fi->fib_net; 695 struct fib_config fib_cfg; 696 struct fib_nh *nh; 697 int ret; 698 699 change_nexthops(fi) { 700 int attrlen; 701 702 memset(&fib_cfg, 0, sizeof(fib_cfg)); 703 704 if (!rtnh_ok(rtnh, remaining)) { 705 NL_SET_ERR_MSG(extack, 706 "Invalid nexthop configuration - extra data after nexthop"); 707 return -EINVAL; 708 } 709 710 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 711 NL_SET_ERR_MSG(extack, 712 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 713 return -EINVAL; 714 } 715 716 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 717 fib_cfg.fc_oif = rtnh->rtnh_ifindex; 718 719 attrlen = rtnh_attrlen(rtnh); 720 if (attrlen > 0) { 721 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 722 723 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 724 nlav = nla_find(attrs, attrlen, RTA_VIA); 725 if (nla && nlav) { 726 NL_SET_ERR_MSG(extack, 727 "Nexthop configuration can not contain both GATEWAY and VIA"); 728 return -EINVAL; 729 } 730 if (nla) { 731 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, 732 extack); 733 if (ret) 734 goto errout; 735 736 if (fib_cfg.fc_gw4) 737 fib_cfg.fc_gw_family = AF_INET; 738 } else if (nlav) { 739 ret = fib_gw_from_via(&fib_cfg, nlav, extack); 740 if (ret) 741 goto errout; 742 } 743 744 nla = nla_find(attrs, attrlen, RTA_FLOW); 745 if (nla) { 746 if (nla_len(nla) < sizeof(u32)) { 747 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 748 return -EINVAL; 749 } 750 fib_cfg.fc_flow = nla_get_u32(nla); 751 } 752 753 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); 754 /* RTA_ENCAP_TYPE length checked in 755 * lwtunnel_valid_encap_type_attr 756 */ 757 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); 758 if (nla) 759 fib_cfg.fc_encap_type = nla_get_u16(nla); 760 } 761 762 ret = fib_nh_init(net, nexthop_nh, &fib_cfg, 763 rtnh->rtnh_hops + 1, extack); 764 if (ret) 765 goto errout; 766 767 rtnh = rtnh_next(rtnh, &remaining); 768 } endfor_nexthops(fi); 769 770 ret = -EINVAL; 771 nh = fib_info_nh(fi, 0); 772 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { 773 NL_SET_ERR_MSG(extack, 774 "Nexthop device index does not match RTA_OIF"); 775 goto errout; 776 } 777 if (cfg->fc_gw_family) { 778 if (cfg->fc_gw_family != nh->fib_nh_gw_family || 779 (cfg->fc_gw_family == AF_INET && 780 nh->fib_nh_gw4 != cfg->fc_gw4) || 781 (cfg->fc_gw_family == AF_INET6 && 782 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { 783 NL_SET_ERR_MSG(extack, 784 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); 785 goto errout; 786 } 787 } 788#ifdef CONFIG_IP_ROUTE_CLASSID 789 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { 790 NL_SET_ERR_MSG(extack, 791 "Nexthop class id does not match RTA_FLOW"); 792 goto errout; 793 } 794#endif 795 ret = 0; 796errout: 797 return ret; 798} 799 800/* only called when fib_nh is integrated into fib_info */ 801static void fib_rebalance(struct fib_info *fi) 802{ 803 int total; 804 int w; 805 806 if (fib_info_num_path(fi) < 2) 807 return; 808 809 total = 0; 810 for_nexthops(fi) { 811 if (nh->fib_nh_flags & RTNH_F_DEAD) 812 continue; 813 814 if (ip_ignore_linkdown(nh->fib_nh_dev) && 815 nh->fib_nh_flags & RTNH_F_LINKDOWN) 816 continue; 817 818 total += nh->fib_nh_weight; 819 } endfor_nexthops(fi); 820 821 w = 0; 822 change_nexthops(fi) { 823 int upper_bound; 824 825 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { 826 upper_bound = -1; 827 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && 828 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { 829 upper_bound = -1; 830 } else { 831 w += nexthop_nh->fib_nh_weight; 832 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 833 total) - 1; 834 } 835 836 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); 837 } endfor_nexthops(fi); 838} 839#else /* CONFIG_IP_ROUTE_MULTIPATH */ 840 841static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 842 int remaining, struct fib_config *cfg, 843 struct netlink_ext_ack *extack) 844{ 845 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); 846 847 return -EINVAL; 848} 849 850#define fib_rebalance(fi) do { } while (0) 851 852#endif /* CONFIG_IP_ROUTE_MULTIPATH */ 853 854static int fib_encap_match(struct net *net, u16 encap_type, 855 struct nlattr *encap, 856 const struct fib_nh *nh, 857 const struct fib_config *cfg, 858 struct netlink_ext_ack *extack) 859{ 860 struct lwtunnel_state *lwtstate; 861 int ret, result = 0; 862 863 if (encap_type == LWTUNNEL_ENCAP_NONE) 864 return 0; 865 866 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, 867 cfg, &lwtstate, extack); 868 if (!ret) { 869 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); 870 lwtstate_free(lwtstate); 871 } 872 873 return result; 874} 875 876int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, 877 struct netlink_ext_ack *extack) 878{ 879#ifdef CONFIG_IP_ROUTE_MULTIPATH 880 struct rtnexthop *rtnh; 881 int remaining; 882#endif 883 884 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 885 return 1; 886 887 if (cfg->fc_nh_id) { 888 if (fi->nh && cfg->fc_nh_id == fi->nh->id) 889 return 0; 890 return 1; 891 } 892 893 if (fi->nh) { 894 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) 895 return 1; 896 return 0; 897 } 898 899 if (cfg->fc_oif || cfg->fc_gw_family) { 900 struct fib_nh *nh; 901 902 nh = fib_info_nh(fi, 0); 903 if (cfg->fc_encap) { 904 if (fib_encap_match(net, cfg->fc_encap_type, 905 cfg->fc_encap, nh, cfg, extack)) 906 return 1; 907 } 908#ifdef CONFIG_IP_ROUTE_CLASSID 909 if (cfg->fc_flow && 910 cfg->fc_flow != nh->nh_tclassid) 911 return 1; 912#endif 913 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || 914 (cfg->fc_gw_family && 915 cfg->fc_gw_family != nh->fib_nh_gw_family)) 916 return 1; 917 918 if (cfg->fc_gw_family == AF_INET && 919 cfg->fc_gw4 != nh->fib_nh_gw4) 920 return 1; 921 922 if (cfg->fc_gw_family == AF_INET6 && 923 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) 924 return 1; 925 926 return 0; 927 } 928 929#ifdef CONFIG_IP_ROUTE_MULTIPATH 930 if (!cfg->fc_mp) 931 return 0; 932 933 rtnh = cfg->fc_mp; 934 remaining = cfg->fc_mp_len; 935 936 for_nexthops(fi) { 937 int attrlen; 938 939 if (!rtnh_ok(rtnh, remaining)) 940 return -EINVAL; 941 942 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif) 943 return 1; 944 945 attrlen = rtnh_attrlen(rtnh); 946 if (attrlen > 0) { 947 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); 948 int err; 949 950 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 951 nlav = nla_find(attrs, attrlen, RTA_VIA); 952 if (nla && nlav) { 953 NL_SET_ERR_MSG(extack, 954 "Nexthop configuration can not contain both GATEWAY and VIA"); 955 return -EINVAL; 956 } 957 958 if (nla) { 959 __be32 gw; 960 961 err = fib_gw_from_attr(&gw, nla, extack); 962 if (err) 963 return err; 964 965 if (nh->fib_nh_gw_family != AF_INET || 966 gw != nh->fib_nh_gw4) 967 return 1; 968 } else if (nlav) { 969 struct fib_config cfg2; 970 971 err = fib_gw_from_via(&cfg2, nlav, extack); 972 if (err) 973 return err; 974 975 switch (nh->fib_nh_gw_family) { 976 case AF_INET: 977 if (cfg2.fc_gw_family != AF_INET || 978 cfg2.fc_gw4 != nh->fib_nh_gw4) 979 return 1; 980 break; 981 case AF_INET6: 982 if (cfg2.fc_gw_family != AF_INET6 || 983 ipv6_addr_cmp(&cfg2.fc_gw6, 984 &nh->fib_nh_gw6)) 985 return 1; 986 break; 987 } 988 } 989 990#ifdef CONFIG_IP_ROUTE_CLASSID 991 nla = nla_find(attrs, attrlen, RTA_FLOW); 992 if (nla) { 993 if (nla_len(nla) < sizeof(u32)) { 994 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); 995 return -EINVAL; 996 } 997 if (nla_get_u32(nla) != nh->nh_tclassid) 998 return 1; 999 } 1000#endif 1001 } 1002 1003 rtnh = rtnh_next(rtnh, &remaining); 1004 } endfor_nexthops(fi); 1005#endif 1006 return 0; 1007} 1008 1009bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 1010{ 1011 struct nlattr *nla; 1012 int remaining; 1013 1014 if (!cfg->fc_mx) 1015 return true; 1016 1017 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1018 int type = nla_type(nla); 1019 u32 fi_val, val; 1020 1021 if (!type) 1022 continue; 1023 if (type > RTAX_MAX) 1024 return false; 1025 1026 type = array_index_nospec(type, RTAX_MAX + 1); 1027 if (type == RTAX_CC_ALGO) { 1028 char tmp[TCP_CA_NAME_MAX]; 1029 bool ecn_ca = false; 1030 1031 nla_strlcpy(tmp, nla, sizeof(tmp)); 1032 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1033 } else { 1034 if (nla_len(nla) != sizeof(u32)) 1035 return false; 1036 val = nla_get_u32(nla); 1037 } 1038 1039 fi_val = fi->fib_metrics->metrics[type - 1]; 1040 if (type == RTAX_FEATURES) 1041 fi_val &= ~DST_FEATURE_ECN_CA; 1042 1043 if (fi_val != val) 1044 return false; 1045 } 1046 1047 return true; 1048} 1049 1050static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, 1051 u32 table, struct netlink_ext_ack *extack) 1052{ 1053 struct fib6_config cfg = { 1054 .fc_table = table, 1055 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, 1056 .fc_ifindex = nh->fib_nh_oif, 1057 .fc_gateway = nh->fib_nh_gw6, 1058 }; 1059 struct fib6_nh fib6_nh = {}; 1060 int err; 1061 1062 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); 1063 if (!err) { 1064 nh->fib_nh_dev = fib6_nh.fib_nh_dev; 1065 dev_hold(nh->fib_nh_dev); 1066 nh->fib_nh_oif = nh->fib_nh_dev->ifindex; 1067 nh->fib_nh_scope = RT_SCOPE_LINK; 1068 1069 ipv6_stub->fib6_nh_release(&fib6_nh); 1070 } 1071 1072 return err; 1073} 1074 1075/* 1076 * Picture 1077 * ------- 1078 * 1079 * Semantics of nexthop is very messy by historical reasons. 1080 * We have to take into account, that: 1081 * a) gateway can be actually local interface address, 1082 * so that gatewayed route is direct. 1083 * b) gateway must be on-link address, possibly 1084 * described not by an ifaddr, but also by a direct route. 1085 * c) If both gateway and interface are specified, they should not 1086 * contradict. 1087 * d) If we use tunnel routes, gateway could be not on-link. 1088 * 1089 * Attempt to reconcile all of these (alas, self-contradictory) conditions 1090 * results in pretty ugly and hairy code with obscure logic. 1091 * 1092 * I chose to generalized it instead, so that the size 1093 * of code does not increase practically, but it becomes 1094 * much more general. 1095 * Every prefix is assigned a "scope" value: "host" is local address, 1096 * "link" is direct route, 1097 * [ ... "site" ... "interior" ... ] 1098 * and "universe" is true gateway route with global meaning. 1099 * 1100 * Every prefix refers to a set of "nexthop"s (gw, oif), 1101 * where gw must have narrower scope. This recursion stops 1102 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 1103 * which means that gw is forced to be on link. 1104 * 1105 * Code is still hairy, but now it is apparently logically 1106 * consistent and very flexible. F.e. as by-product it allows 1107 * to co-exists in peace independent exterior and interior 1108 * routing processes. 1109 * 1110 * Normally it looks as following. 1111 * 1112 * {universe prefix} -> (gw, oif) [scope link] 1113 * | 1114 * |-> {link prefix} -> (gw, oif) [scope local] 1115 * | 1116 * |-> {local prefix} (terminal node) 1117 */ 1118static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table, 1119 u8 scope, struct netlink_ext_ack *extack) 1120{ 1121 struct net_device *dev; 1122 struct fib_result res; 1123 int err = 0; 1124 1125 if (nh->fib_nh_flags & RTNH_F_ONLINK) { 1126 unsigned int addr_type; 1127 1128 if (scope >= RT_SCOPE_LINK) { 1129 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); 1130 return -EINVAL; 1131 } 1132 dev = __dev_get_by_index(net, nh->fib_nh_oif); 1133 if (!dev) { 1134 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); 1135 return -ENODEV; 1136 } 1137 if (!(dev->flags & IFF_UP)) { 1138 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1139 return -ENETDOWN; 1140 } 1141 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); 1142 if (addr_type != RTN_UNICAST) { 1143 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1144 return -EINVAL; 1145 } 1146 if (!netif_carrier_ok(dev)) 1147 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1148 nh->fib_nh_dev = dev; 1149 dev_hold(dev); 1150 nh->fib_nh_scope = RT_SCOPE_LINK; 1151 return 0; 1152 } 1153 rcu_read_lock(); 1154 { 1155 struct fib_table *tbl = NULL; 1156 struct flowi4 fl4 = { 1157 .daddr = nh->fib_nh_gw4, 1158 .flowi4_scope = scope + 1, 1159 .flowi4_oif = nh->fib_nh_oif, 1160 .flowi4_iif = LOOPBACK_IFINDEX, 1161 }; 1162 1163 /* It is not necessary, but requires a bit of thinking */ 1164 if (fl4.flowi4_scope < RT_SCOPE_LINK) 1165 fl4.flowi4_scope = RT_SCOPE_LINK; 1166 1167 if (table && table != RT_TABLE_MAIN) 1168 tbl = fib_get_table(net, table); 1169 1170 if (tbl) 1171 err = fib_table_lookup(tbl, &fl4, &res, 1172 FIB_LOOKUP_IGNORE_LINKSTATE | 1173 FIB_LOOKUP_NOREF); 1174 1175 /* on error or if no table given do full lookup. This 1176 * is needed for example when nexthops are in the local 1177 * table rather than the given table 1178 */ 1179 if (!tbl || err) { 1180 err = fib_lookup(net, &fl4, &res, 1181 FIB_LOOKUP_IGNORE_LINKSTATE); 1182 } 1183 1184 if (err) { 1185 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1186 goto out; 1187 } 1188 } 1189 1190 err = -EINVAL; 1191 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 1192 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 1193 goto out; 1194 } 1195 nh->fib_nh_scope = res.scope; 1196 nh->fib_nh_oif = FIB_RES_OIF(res); 1197 nh->fib_nh_dev = dev = FIB_RES_DEV(res); 1198 if (!dev) { 1199 NL_SET_ERR_MSG(extack, 1200 "No egress device for nexthop gateway"); 1201 goto out; 1202 } 1203 dev_hold(dev); 1204 if (!netif_carrier_ok(dev)) 1205 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1206 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 1207out: 1208 rcu_read_unlock(); 1209 return err; 1210} 1211 1212static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, 1213 struct netlink_ext_ack *extack) 1214{ 1215 struct in_device *in_dev; 1216 int err; 1217 1218 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 1219 NL_SET_ERR_MSG(extack, 1220 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 1221 return -EINVAL; 1222 } 1223 1224 rcu_read_lock(); 1225 1226 err = -ENODEV; 1227 in_dev = inetdev_by_index(net, nh->fib_nh_oif); 1228 if (!in_dev) 1229 goto out; 1230 err = -ENETDOWN; 1231 if (!(in_dev->dev->flags & IFF_UP)) { 1232 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 1233 goto out; 1234 } 1235 1236 nh->fib_nh_dev = in_dev->dev; 1237 dev_hold(nh->fib_nh_dev); 1238 nh->fib_nh_scope = RT_SCOPE_LINK; 1239 if (!netif_carrier_ok(nh->fib_nh_dev)) 1240 nh->fib_nh_flags |= RTNH_F_LINKDOWN; 1241 err = 0; 1242out: 1243 rcu_read_unlock(); 1244 return err; 1245} 1246 1247int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, 1248 struct netlink_ext_ack *extack) 1249{ 1250 int err; 1251 1252 if (nh->fib_nh_gw_family == AF_INET) 1253 err = fib_check_nh_v4_gw(net, nh, table, scope, extack); 1254 else if (nh->fib_nh_gw_family == AF_INET6) 1255 err = fib_check_nh_v6_gw(net, nh, table, extack); 1256 else 1257 err = fib_check_nh_nongw(net, nh, extack); 1258 1259 return err; 1260} 1261 1262static inline unsigned int fib_laddr_hashfn(__be32 val) 1263{ 1264 unsigned int mask = (fib_info_hash_size - 1); 1265 1266 return ((__force u32)val ^ 1267 ((__force u32)val >> 7) ^ 1268 ((__force u32)val >> 14)) & mask; 1269} 1270 1271static struct hlist_head *fib_info_hash_alloc(int bytes) 1272{ 1273 if (bytes <= PAGE_SIZE) 1274 return kzalloc(bytes, GFP_KERNEL); 1275 else 1276 return (struct hlist_head *) 1277 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 1278 get_order(bytes)); 1279} 1280 1281static void fib_info_hash_free(struct hlist_head *hash, int bytes) 1282{ 1283 if (!hash) 1284 return; 1285 1286 if (bytes <= PAGE_SIZE) 1287 kfree(hash); 1288 else 1289 free_pages((unsigned long) hash, get_order(bytes)); 1290} 1291 1292static void fib_info_hash_move(struct hlist_head *new_info_hash, 1293 struct hlist_head *new_laddrhash, 1294 unsigned int new_size) 1295{ 1296 struct hlist_head *old_info_hash, *old_laddrhash; 1297 unsigned int old_size = fib_info_hash_size; 1298 unsigned int i, bytes; 1299 1300 spin_lock_bh(&fib_info_lock); 1301 old_info_hash = fib_info_hash; 1302 old_laddrhash = fib_info_laddrhash; 1303 fib_info_hash_size = new_size; 1304 1305 for (i = 0; i < old_size; i++) { 1306 struct hlist_head *head = &fib_info_hash[i]; 1307 struct hlist_node *n; 1308 struct fib_info *fi; 1309 1310 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 1311 struct hlist_head *dest; 1312 unsigned int new_hash; 1313 1314 new_hash = fib_info_hashfn(fi); 1315 dest = &new_info_hash[new_hash]; 1316 hlist_add_head(&fi->fib_hash, dest); 1317 } 1318 } 1319 fib_info_hash = new_info_hash; 1320 1321 for (i = 0; i < old_size; i++) { 1322 struct hlist_head *lhead = &fib_info_laddrhash[i]; 1323 struct hlist_node *n; 1324 struct fib_info *fi; 1325 1326 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 1327 struct hlist_head *ldest; 1328 unsigned int new_hash; 1329 1330 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 1331 ldest = &new_laddrhash[new_hash]; 1332 hlist_add_head(&fi->fib_lhash, ldest); 1333 } 1334 } 1335 fib_info_laddrhash = new_laddrhash; 1336 1337 spin_unlock_bh(&fib_info_lock); 1338 1339 bytes = old_size * sizeof(struct hlist_head *); 1340 fib_info_hash_free(old_info_hash, bytes); 1341 fib_info_hash_free(old_laddrhash, bytes); 1342} 1343 1344__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, 1345 unsigned char scope) 1346{ 1347 struct fib_nh *nh; 1348 __be32 saddr; 1349 1350 if (nhc->nhc_family != AF_INET) 1351 return inet_select_addr(nhc->nhc_dev, 0, scope); 1352 1353 nh = container_of(nhc, struct fib_nh, nh_common); 1354 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); 1355 1356 WRITE_ONCE(nh->nh_saddr, saddr); 1357 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); 1358 1359 return saddr; 1360} 1361 1362__be32 fib_result_prefsrc(struct net *net, struct fib_result *res) 1363{ 1364 struct fib_nh_common *nhc = res->nhc; 1365 1366 if (res->fi->fib_prefsrc) 1367 return res->fi->fib_prefsrc; 1368 1369 if (nhc->nhc_family == AF_INET) { 1370 struct fib_nh *nh; 1371 1372 nh = container_of(nhc, struct fib_nh, nh_common); 1373 if (READ_ONCE(nh->nh_saddr_genid) == 1374 atomic_read(&net->ipv4.dev_addr_genid)) 1375 return READ_ONCE(nh->nh_saddr); 1376 } 1377 1378 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); 1379} 1380 1381static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 1382{ 1383 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 1384 fib_prefsrc != cfg->fc_dst) { 1385 u32 tb_id = cfg->fc_table; 1386 int rc; 1387 1388 if (tb_id == RT_TABLE_MAIN) 1389 tb_id = RT_TABLE_LOCAL; 1390 1391 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1392 fib_prefsrc, tb_id); 1393 1394 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1395 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1396 fib_prefsrc, RT_TABLE_LOCAL); 1397 } 1398 1399 if (rc != RTN_LOCAL) 1400 return false; 1401 } 1402 return true; 1403} 1404 1405struct fib_info *fib_create_info(struct fib_config *cfg, 1406 struct netlink_ext_ack *extack) 1407{ 1408 int err; 1409 struct fib_info *fi = NULL; 1410 struct nexthop *nh = NULL; 1411 struct fib_info *ofi; 1412 int nhs = 1; 1413 struct net *net = cfg->fc_nlinfo.nl_net; 1414 1415 if (cfg->fc_type > RTN_MAX) 1416 goto err_inval; 1417 1418 /* Fast check to catch the most weird cases */ 1419 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1420 NL_SET_ERR_MSG(extack, "Invalid scope"); 1421 goto err_inval; 1422 } 1423 1424 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1425 NL_SET_ERR_MSG(extack, 1426 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1427 goto err_inval; 1428 } 1429 1430 if (cfg->fc_nh_id) { 1431 if (!cfg->fc_mx) { 1432 fi = fib_find_info_nh(net, cfg); 1433 if (fi) { 1434 fi->fib_treeref++; 1435 return fi; 1436 } 1437 } 1438 1439 nh = nexthop_find_by_id(net, cfg->fc_nh_id); 1440 if (!nh) { 1441 NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); 1442 goto err_inval; 1443 } 1444 nhs = 0; 1445 } 1446 1447#ifdef CONFIG_IP_ROUTE_MULTIPATH 1448 if (cfg->fc_mp) { 1449 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1450 if (nhs == 0) 1451 goto err_inval; 1452 } 1453#endif 1454 1455 err = -ENOBUFS; 1456 1457 /* Paired with WRITE_ONCE() in fib_release_info() */ 1458 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) { 1459 unsigned int new_size = fib_info_hash_size << 1; 1460 struct hlist_head *new_info_hash; 1461 struct hlist_head *new_laddrhash; 1462 unsigned int bytes; 1463 1464 if (!new_size) 1465 new_size = 16; 1466 bytes = new_size * sizeof(struct hlist_head *); 1467 new_info_hash = fib_info_hash_alloc(bytes); 1468 new_laddrhash = fib_info_hash_alloc(bytes); 1469 if (!new_info_hash || !new_laddrhash) { 1470 fib_info_hash_free(new_info_hash, bytes); 1471 fib_info_hash_free(new_laddrhash, bytes); 1472 } else 1473 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1474 1475 if (!fib_info_hash_size) 1476 goto failure; 1477 } 1478 1479 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); 1480 if (!fi) 1481 goto failure; 1482 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx, 1483 cfg->fc_mx_len, extack); 1484 if (IS_ERR(fi->fib_metrics)) { 1485 err = PTR_ERR(fi->fib_metrics); 1486 kfree(fi); 1487 return ERR_PTR(err); 1488 } 1489 1490 fi->fib_net = net; 1491 fi->fib_protocol = cfg->fc_protocol; 1492 fi->fib_scope = cfg->fc_scope; 1493 fi->fib_flags = cfg->fc_flags; 1494 fi->fib_priority = cfg->fc_priority; 1495 fi->fib_prefsrc = cfg->fc_prefsrc; 1496 fi->fib_type = cfg->fc_type; 1497 fi->fib_tb_id = cfg->fc_table; 1498 1499 fi->fib_nhs = nhs; 1500 if (nh) { 1501 if (!nexthop_get(nh)) { 1502 NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); 1503 err = -EINVAL; 1504 } else { 1505 err = 0; 1506 fi->nh = nh; 1507 } 1508 } else { 1509 change_nexthops(fi) { 1510 nexthop_nh->nh_parent = fi; 1511 } endfor_nexthops(fi) 1512 1513 if (cfg->fc_mp) 1514 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, 1515 extack); 1516 else 1517 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); 1518 } 1519 1520 if (err != 0) 1521 goto failure; 1522 1523 if (fib_props[cfg->fc_type].error) { 1524 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { 1525 NL_SET_ERR_MSG(extack, 1526 "Gateway, device and multipath can not be specified for this route type"); 1527 goto err_inval; 1528 } 1529 goto link_it; 1530 } else { 1531 switch (cfg->fc_type) { 1532 case RTN_UNICAST: 1533 case RTN_LOCAL: 1534 case RTN_BROADCAST: 1535 case RTN_ANYCAST: 1536 case RTN_MULTICAST: 1537 break; 1538 default: 1539 NL_SET_ERR_MSG(extack, "Invalid route type"); 1540 goto err_inval; 1541 } 1542 } 1543 1544 if (cfg->fc_scope > RT_SCOPE_HOST) { 1545 NL_SET_ERR_MSG(extack, "Invalid scope"); 1546 goto err_inval; 1547 } 1548 1549 if (fi->nh) { 1550 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); 1551 if (err) 1552 goto failure; 1553 } else if (cfg->fc_scope == RT_SCOPE_HOST) { 1554 struct fib_nh *nh = fi->fib_nh; 1555 1556 /* Local address is added. */ 1557 if (nhs != 1) { 1558 NL_SET_ERR_MSG(extack, 1559 "Route with host scope can not have multiple nexthops"); 1560 goto err_inval; 1561 } 1562 if (nh->fib_nh_gw_family) { 1563 NL_SET_ERR_MSG(extack, 1564 "Route with host scope can not have a gateway"); 1565 goto err_inval; 1566 } 1567 nh->fib_nh_scope = RT_SCOPE_NOWHERE; 1568 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); 1569 err = -ENODEV; 1570 if (!nh->fib_nh_dev) 1571 goto failure; 1572 } else { 1573 int linkdown = 0; 1574 1575 change_nexthops(fi) { 1576 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, 1577 cfg->fc_table, cfg->fc_scope, 1578 extack); 1579 if (err != 0) 1580 goto failure; 1581 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) 1582 linkdown++; 1583 } endfor_nexthops(fi) 1584 if (linkdown == fi->fib_nhs) 1585 fi->fib_flags |= RTNH_F_LINKDOWN; 1586 } 1587 1588 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1589 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1590 goto err_inval; 1591 } 1592 1593 if (!fi->nh) { 1594 change_nexthops(fi) { 1595 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, 1596 fi->fib_scope); 1597 if (nexthop_nh->fib_nh_gw_family == AF_INET6) 1598 fi->fib_nh_is_v6 = true; 1599 } endfor_nexthops(fi) 1600 1601 fib_rebalance(fi); 1602 } 1603 1604link_it: 1605 ofi = fib_find_info(fi); 1606 if (ofi) { 1607 /* fib_table_lookup() should not see @fi yet. */ 1608 fi->fib_dead = 1; 1609 free_fib_info(fi); 1610 ofi->fib_treeref++; 1611 return ofi; 1612 } 1613 1614 fi->fib_treeref++; 1615 refcount_set(&fi->fib_clntref, 1); 1616 spin_lock_bh(&fib_info_lock); 1617 fib_info_cnt++; 1618 hlist_add_head(&fi->fib_hash, 1619 &fib_info_hash[fib_info_hashfn(fi)]); 1620 if (fi->fib_prefsrc) { 1621 struct hlist_head *head; 1622 1623 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1624 hlist_add_head(&fi->fib_lhash, head); 1625 } 1626 if (fi->nh) { 1627 list_add(&fi->nh_list, &nh->fi_list); 1628 } else { 1629 change_nexthops(fi) { 1630 struct hlist_head *head; 1631 1632 if (!nexthop_nh->fib_nh_dev) 1633 continue; 1634 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev); 1635 hlist_add_head(&nexthop_nh->nh_hash, head); 1636 } endfor_nexthops(fi) 1637 } 1638 spin_unlock_bh(&fib_info_lock); 1639 return fi; 1640 1641err_inval: 1642 err = -EINVAL; 1643 1644failure: 1645 if (fi) { 1646 /* fib_table_lookup() should not see @fi yet. */ 1647 fi->fib_dead = 1; 1648 free_fib_info(fi); 1649 } 1650 1651 return ERR_PTR(err); 1652} 1653 1654int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, 1655 u8 rt_family, unsigned char *flags, bool skip_oif) 1656{ 1657 if (nhc->nhc_flags & RTNH_F_DEAD) 1658 *flags |= RTNH_F_DEAD; 1659 1660 if (nhc->nhc_flags & RTNH_F_LINKDOWN) { 1661 *flags |= RTNH_F_LINKDOWN; 1662 1663 rcu_read_lock(); 1664 switch (nhc->nhc_family) { 1665 case AF_INET: 1666 if (ip_ignore_linkdown(nhc->nhc_dev)) 1667 *flags |= RTNH_F_DEAD; 1668 break; 1669 case AF_INET6: 1670 if (ip6_ignore_linkdown(nhc->nhc_dev)) 1671 *flags |= RTNH_F_DEAD; 1672 break; 1673 } 1674 rcu_read_unlock(); 1675 } 1676 1677 switch (nhc->nhc_gw_family) { 1678 case AF_INET: 1679 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) 1680 goto nla_put_failure; 1681 break; 1682 case AF_INET6: 1683 /* if gateway family does not match nexthop family 1684 * gateway is encoded as RTA_VIA 1685 */ 1686 if (rt_family != nhc->nhc_gw_family) { 1687 int alen = sizeof(struct in6_addr); 1688 struct nlattr *nla; 1689 struct rtvia *via; 1690 1691 nla = nla_reserve(skb, RTA_VIA, alen + 2); 1692 if (!nla) 1693 goto nla_put_failure; 1694 1695 via = nla_data(nla); 1696 via->rtvia_family = AF_INET6; 1697 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); 1698 } else if (nla_put_in6_addr(skb, RTA_GATEWAY, 1699 &nhc->nhc_gw.ipv6) < 0) { 1700 goto nla_put_failure; 1701 } 1702 break; 1703 } 1704 1705 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK); 1706 if (nhc->nhc_flags & RTNH_F_OFFLOAD) 1707 *flags |= RTNH_F_OFFLOAD; 1708 1709 if (!skip_oif && nhc->nhc_dev && 1710 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) 1711 goto nla_put_failure; 1712 1713 if (nhc->nhc_lwtstate && 1714 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, 1715 RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 1716 goto nla_put_failure; 1717 1718 return 0; 1719 1720nla_put_failure: 1721 return -EMSGSIZE; 1722} 1723EXPORT_SYMBOL_GPL(fib_nexthop_info); 1724 1725#if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) 1726int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, 1727 int nh_weight, u8 rt_family, u32 nh_tclassid) 1728{ 1729 const struct net_device *dev = nhc->nhc_dev; 1730 struct rtnexthop *rtnh; 1731 unsigned char flags = 0; 1732 1733 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1734 if (!rtnh) 1735 goto nla_put_failure; 1736 1737 rtnh->rtnh_hops = nh_weight - 1; 1738 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; 1739 1740 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) 1741 goto nla_put_failure; 1742 1743 rtnh->rtnh_flags = flags; 1744 1745 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) 1746 goto nla_put_failure; 1747 1748 /* length of rtnetlink header + attributes */ 1749 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; 1750 1751 return 0; 1752 1753nla_put_failure: 1754 return -EMSGSIZE; 1755} 1756EXPORT_SYMBOL_GPL(fib_add_nexthop); 1757#endif 1758 1759#ifdef CONFIG_IP_ROUTE_MULTIPATH 1760static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1761{ 1762 struct nlattr *mp; 1763 1764 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); 1765 if (!mp) 1766 goto nla_put_failure; 1767 1768 if (unlikely(fi->nh)) { 1769 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) 1770 goto nla_put_failure; 1771 goto mp_end; 1772 } 1773 1774 for_nexthops(fi) { 1775 u32 nh_tclassid = 0; 1776#ifdef CONFIG_IP_ROUTE_CLASSID 1777 nh_tclassid = nh->nh_tclassid; 1778#endif 1779 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, 1780 AF_INET, nh_tclassid) < 0) 1781 goto nla_put_failure; 1782 } endfor_nexthops(fi); 1783 1784mp_end: 1785 nla_nest_end(skb, mp); 1786 1787 return 0; 1788 1789nla_put_failure: 1790 return -EMSGSIZE; 1791} 1792#else 1793static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 1794{ 1795 return 0; 1796} 1797#endif 1798 1799int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1800 struct fib_rt_info *fri, unsigned int flags) 1801{ 1802 unsigned int nhs = fib_info_num_path(fri->fi); 1803 struct fib_info *fi = fri->fi; 1804 u32 tb_id = fri->tb_id; 1805 struct nlmsghdr *nlh; 1806 struct rtmsg *rtm; 1807 1808 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1809 if (!nlh) 1810 return -EMSGSIZE; 1811 1812 rtm = nlmsg_data(nlh); 1813 rtm->rtm_family = AF_INET; 1814 rtm->rtm_dst_len = fri->dst_len; 1815 rtm->rtm_src_len = 0; 1816 rtm->rtm_tos = fri->tos; 1817 if (tb_id < 256) 1818 rtm->rtm_table = tb_id; 1819 else 1820 rtm->rtm_table = RT_TABLE_COMPAT; 1821 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1822 goto nla_put_failure; 1823 rtm->rtm_type = fri->type; 1824 rtm->rtm_flags = fi->fib_flags; 1825 rtm->rtm_scope = fi->fib_scope; 1826 rtm->rtm_protocol = fi->fib_protocol; 1827 1828 if (rtm->rtm_dst_len && 1829 nla_put_in_addr(skb, RTA_DST, fri->dst)) 1830 goto nla_put_failure; 1831 if (fi->fib_priority && 1832 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1833 goto nla_put_failure; 1834 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1835 goto nla_put_failure; 1836 1837 if (fi->fib_prefsrc && 1838 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1839 goto nla_put_failure; 1840 1841 if (fi->nh) { 1842 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) 1843 goto nla_put_failure; 1844 if (nexthop_is_blackhole(fi->nh)) 1845 rtm->rtm_type = RTN_BLACKHOLE; 1846 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) 1847 goto offload; 1848 } 1849 1850 if (nhs == 1) { 1851 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); 1852 unsigned char flags = 0; 1853 1854 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) 1855 goto nla_put_failure; 1856 1857 rtm->rtm_flags = flags; 1858#ifdef CONFIG_IP_ROUTE_CLASSID 1859 if (nhc->nhc_family == AF_INET) { 1860 struct fib_nh *nh; 1861 1862 nh = container_of(nhc, struct fib_nh, nh_common); 1863 if (nh->nh_tclassid && 1864 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1865 goto nla_put_failure; 1866 } 1867#endif 1868 } else { 1869 if (fib_add_multipath(skb, fi) < 0) 1870 goto nla_put_failure; 1871 } 1872 1873offload: 1874 if (fri->offload) 1875 rtm->rtm_flags |= RTM_F_OFFLOAD; 1876 if (fri->trap) 1877 rtm->rtm_flags |= RTM_F_TRAP; 1878 1879 nlmsg_end(skb, nlh); 1880 return 0; 1881 1882nla_put_failure: 1883 nlmsg_cancel(skb, nlh); 1884 return -EMSGSIZE; 1885} 1886 1887/* 1888 * Update FIB if: 1889 * - local address disappeared -> we must delete all the entries 1890 * referring to it. 1891 * - device went down -> we must shutdown all nexthops going via it. 1892 */ 1893int fib_sync_down_addr(struct net_device *dev, __be32 local) 1894{ 1895 int ret = 0; 1896 unsigned int hash = fib_laddr_hashfn(local); 1897 struct hlist_head *head = &fib_info_laddrhash[hash]; 1898 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; 1899 struct net *net = dev_net(dev); 1900 struct fib_info *fi; 1901 1902 if (!fib_info_laddrhash || local == 0) 1903 return 0; 1904 1905 hlist_for_each_entry(fi, head, fib_lhash) { 1906 if (!net_eq(fi->fib_net, net) || 1907 fi->fib_tb_id != tb_id) 1908 continue; 1909 if (fi->fib_prefsrc == local) { 1910 fi->fib_flags |= RTNH_F_DEAD; 1911 fi->pfsrc_removed = true; 1912 ret++; 1913 } 1914 } 1915 return ret; 1916} 1917 1918static int call_fib_nh_notifiers(struct fib_nh *nh, 1919 enum fib_event_type event_type) 1920{ 1921 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); 1922 struct fib_nh_notifier_info info = { 1923 .fib_nh = nh, 1924 }; 1925 1926 switch (event_type) { 1927 case FIB_EVENT_NH_ADD: 1928 if (nh->fib_nh_flags & RTNH_F_DEAD) 1929 break; 1930 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) 1931 break; 1932 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, 1933 &info.info); 1934 case FIB_EVENT_NH_DEL: 1935 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || 1936 (nh->fib_nh_flags & RTNH_F_DEAD)) 1937 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), 1938 event_type, &info.info); 1939 default: 1940 break; 1941 } 1942 1943 return NOTIFY_DONE; 1944} 1945 1946/* Update the PMTU of exceptions when: 1947 * - the new MTU of the first hop becomes smaller than the PMTU 1948 * - the old MTU was the same as the PMTU, and it limited discovery of 1949 * larger MTUs on the path. With that limit raised, we can now 1950 * discover larger MTUs 1951 * A special case is locked exceptions, for which the PMTU is smaller 1952 * than the minimal accepted PMTU: 1953 * - if the new MTU is greater than the PMTU, don't make any change 1954 * - otherwise, unlock and set PMTU 1955 */ 1956void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) 1957{ 1958 struct fnhe_hash_bucket *bucket; 1959 int i; 1960 1961 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); 1962 if (!bucket) 1963 return; 1964 1965 for (i = 0; i < FNHE_HASH_SIZE; i++) { 1966 struct fib_nh_exception *fnhe; 1967 1968 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); 1969 fnhe; 1970 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { 1971 if (fnhe->fnhe_mtu_locked) { 1972 if (new <= fnhe->fnhe_pmtu) { 1973 fnhe->fnhe_pmtu = new; 1974 fnhe->fnhe_mtu_locked = false; 1975 } 1976 } else if (new < fnhe->fnhe_pmtu || 1977 orig == fnhe->fnhe_pmtu) { 1978 fnhe->fnhe_pmtu = new; 1979 } 1980 } 1981 } 1982} 1983 1984void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 1985{ 1986 struct hlist_head *head = fib_info_devhash_bucket(dev); 1987 struct fib_nh *nh; 1988 1989 hlist_for_each_entry(nh, head, nh_hash) { 1990 if (nh->fib_nh_dev == dev) 1991 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); 1992 } 1993} 1994 1995/* Event force Flags Description 1996 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1997 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1998 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1999 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 2000 * 2001 * only used when fib_nh is built into fib_info 2002 */ 2003int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 2004{ 2005 struct hlist_head *head = fib_info_devhash_bucket(dev); 2006 struct fib_info *prev_fi = NULL; 2007 int scope = RT_SCOPE_NOWHERE; 2008 struct fib_nh *nh; 2009 int ret = 0; 2010 2011 if (force) 2012 scope = -1; 2013 2014 hlist_for_each_entry(nh, head, nh_hash) { 2015 struct fib_info *fi = nh->nh_parent; 2016 int dead; 2017 2018 BUG_ON(!fi->fib_nhs); 2019 if (nh->fib_nh_dev != dev || fi == prev_fi) 2020 continue; 2021 prev_fi = fi; 2022 dead = 0; 2023 change_nexthops(fi) { 2024 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) 2025 dead++; 2026 else if (nexthop_nh->fib_nh_dev == dev && 2027 nexthop_nh->fib_nh_scope != scope) { 2028 switch (event) { 2029 case NETDEV_DOWN: 2030 case NETDEV_UNREGISTER: 2031 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; 2032 fallthrough; 2033 case NETDEV_CHANGE: 2034 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; 2035 break; 2036 } 2037 call_fib_nh_notifiers(nexthop_nh, 2038 FIB_EVENT_NH_DEL); 2039 dead++; 2040 } 2041#ifdef CONFIG_IP_ROUTE_MULTIPATH 2042 if (event == NETDEV_UNREGISTER && 2043 nexthop_nh->fib_nh_dev == dev) { 2044 dead = fi->fib_nhs; 2045 break; 2046 } 2047#endif 2048 } endfor_nexthops(fi) 2049 if (dead == fi->fib_nhs) { 2050 switch (event) { 2051 case NETDEV_DOWN: 2052 case NETDEV_UNREGISTER: 2053 fi->fib_flags |= RTNH_F_DEAD; 2054 fallthrough; 2055 case NETDEV_CHANGE: 2056 fi->fib_flags |= RTNH_F_LINKDOWN; 2057 break; 2058 } 2059 ret++; 2060 } 2061 2062 fib_rebalance(fi); 2063 } 2064 2065 return ret; 2066} 2067 2068/* Must be invoked inside of an RCU protected region. */ 2069static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 2070{ 2071 struct fib_info *fi = NULL, *last_resort = NULL; 2072 struct hlist_head *fa_head = res->fa_head; 2073 struct fib_table *tb = res->table; 2074 u8 slen = 32 - res->prefixlen; 2075 int order = -1, last_idx = -1; 2076 struct fib_alias *fa, *fa1 = NULL; 2077 u32 last_prio = res->fi->fib_priority; 2078 u8 last_tos = 0; 2079 2080 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 2081 struct fib_info *next_fi = fa->fa_info; 2082 struct fib_nh_common *nhc; 2083 2084 if (fa->fa_slen != slen) 2085 continue; 2086 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 2087 continue; 2088 if (fa->tb_id != tb->tb_id) 2089 continue; 2090 if (next_fi->fib_priority > last_prio && 2091 fa->fa_tos == last_tos) { 2092 if (last_tos) 2093 continue; 2094 break; 2095 } 2096 if (next_fi->fib_flags & RTNH_F_DEAD) 2097 continue; 2098 last_tos = fa->fa_tos; 2099 last_prio = next_fi->fib_priority; 2100 2101 if (next_fi->fib_scope != res->scope || 2102 fa->fa_type != RTN_UNICAST) 2103 continue; 2104 2105 nhc = fib_info_nhc(next_fi, 0); 2106 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) 2107 continue; 2108 2109 fib_alias_accessed(fa); 2110 2111 if (!fi) { 2112 if (next_fi != res->fi) 2113 break; 2114 fa1 = fa; 2115 } else if (!fib_detect_death(fi, order, &last_resort, 2116 &last_idx, fa1->fa_default)) { 2117 fib_result_assign(res, fi); 2118 fa1->fa_default = order; 2119 goto out; 2120 } 2121 fi = next_fi; 2122 order++; 2123 } 2124 2125 if (order <= 0 || !fi) { 2126 if (fa1) 2127 fa1->fa_default = -1; 2128 goto out; 2129 } 2130 2131 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 2132 fa1->fa_default)) { 2133 fib_result_assign(res, fi); 2134 fa1->fa_default = order; 2135 goto out; 2136 } 2137 2138 if (last_idx >= 0) 2139 fib_result_assign(res, last_resort); 2140 fa1->fa_default = last_idx; 2141out: 2142 return; 2143} 2144 2145/* 2146 * Dead device goes up. We wake up dead nexthops. 2147 * It takes sense only on multipath routes. 2148 * 2149 * only used when fib_nh is built into fib_info 2150 */ 2151int fib_sync_up(struct net_device *dev, unsigned char nh_flags) 2152{ 2153 struct fib_info *prev_fi; 2154 struct hlist_head *head; 2155 struct fib_nh *nh; 2156 int ret; 2157 2158 if (!(dev->flags & IFF_UP)) 2159 return 0; 2160 2161 if (nh_flags & RTNH_F_DEAD) { 2162 unsigned int flags = dev_get_flags(dev); 2163 2164 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 2165 nh_flags |= RTNH_F_LINKDOWN; 2166 } 2167 2168 prev_fi = NULL; 2169 head = fib_info_devhash_bucket(dev); 2170 ret = 0; 2171 2172 hlist_for_each_entry(nh, head, nh_hash) { 2173 struct fib_info *fi = nh->nh_parent; 2174 int alive; 2175 2176 BUG_ON(!fi->fib_nhs); 2177 if (nh->fib_nh_dev != dev || fi == prev_fi) 2178 continue; 2179 2180 prev_fi = fi; 2181 alive = 0; 2182 change_nexthops(fi) { 2183 if (!(nexthop_nh->fib_nh_flags & nh_flags)) { 2184 alive++; 2185 continue; 2186 } 2187 if (!nexthop_nh->fib_nh_dev || 2188 !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) 2189 continue; 2190 if (nexthop_nh->fib_nh_dev != dev || 2191 !__in_dev_get_rtnl(dev)) 2192 continue; 2193 alive++; 2194 nexthop_nh->fib_nh_flags &= ~nh_flags; 2195 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 2196 } endfor_nexthops(fi) 2197 2198 if (alive > 0) { 2199 fi->fib_flags &= ~nh_flags; 2200 ret++; 2201 } 2202 2203 fib_rebalance(fi); 2204 } 2205 2206 return ret; 2207} 2208 2209#ifdef CONFIG_IP_ROUTE_MULTIPATH 2210static bool fib_good_nh(const struct fib_nh *nh) 2211{ 2212 int state = NUD_REACHABLE; 2213 2214 if (nh->fib_nh_scope == RT_SCOPE_LINK) { 2215 struct neighbour *n; 2216 2217 rcu_read_lock_bh(); 2218 2219 if (likely(nh->fib_nh_gw_family == AF_INET)) 2220 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 2221 (__force u32)nh->fib_nh_gw4); 2222 else if (nh->fib_nh_gw_family == AF_INET6) 2223 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, 2224 &nh->fib_nh_gw6); 2225 else 2226 n = NULL; 2227 if (n) 2228 state = n->nud_state; 2229 2230 rcu_read_unlock_bh(); 2231 } 2232 2233 return !!(state & NUD_VALID); 2234} 2235 2236void fib_select_multipath(struct fib_result *res, int hash) 2237{ 2238 struct fib_info *fi = res->fi; 2239 struct net *net = fi->fib_net; 2240 bool first = false; 2241 2242 if (unlikely(res->fi->nh)) { 2243 nexthop_path_fib_result(res, hash); 2244 return; 2245 } 2246 2247 change_nexthops(fi) { 2248 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { 2249 if (!fib_good_nh(nexthop_nh)) 2250 continue; 2251 if (!first) { 2252 res->nh_sel = nhsel; 2253 res->nhc = &nexthop_nh->nh_common; 2254 first = true; 2255 } 2256 } 2257 2258 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) 2259 continue; 2260 2261 res->nh_sel = nhsel; 2262 res->nhc = &nexthop_nh->nh_common; 2263 return; 2264 } endfor_nexthops(fi); 2265} 2266#endif 2267 2268void fib_select_path(struct net *net, struct fib_result *res, 2269 struct flowi4 *fl4, const struct sk_buff *skb) 2270{ 2271 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) 2272 goto check_saddr; 2273 2274#ifdef CONFIG_IP_ROUTE_MULTIPATH 2275 if (fib_info_num_path(res->fi) > 1) { 2276 int h = fib_multipath_hash(net, fl4, skb, NULL); 2277 2278 fib_select_multipath(res, h); 2279 } 2280 else 2281#endif 2282 if (!res->prefixlen && 2283 res->table->tb_num_default > 1 && 2284 res->type == RTN_UNICAST) 2285 fib_select_default(fl4, res); 2286 2287check_saddr: 2288 if (!fl4->saddr) 2289 fl4->saddr = fib_result_prefsrc(net, res); 2290} 2291