1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * IPv4 Forwarding Information Base: semantics. 7 * 8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 #include <linux/uaccess.h> 17 #include <linux/bitops.h> 18 #include <linux/types.h> 19 #include <linux/kernel.h> 20 #include <linux/jiffies.h> 21 #include <linux/mm.h> 22 #include <linux/string.h> 23 #include <linux/socket.h> 24 #include <linux/sockios.h> 25 #include <linux/errno.h> 26 #include <linux/in.h> 27 #include <linux/inet.h> 28 #include <linux/inetdevice.h> 29 #include <linux/netdevice.h> 30 #include <linux/if_arp.h> 31 #include <linux/proc_fs.h> 32 #include <linux/skbuff.h> 33 #include <linux/init.h> 34 #include <linux/slab.h> 35 #include <linux/netlink.h> 36 37 #include <net/arp.h> 38 #include <net/ip.h> 39 #include <net/protocol.h> 40 #include <net/route.h> 41 #include <net/tcp.h> 42 #include <net/sock.h> 43 #include <net/ip_fib.h> 44 #include <net/netlink.h> 45 #include <net/nexthop.h> 46 #include <net/lwtunnel.h> 47 #include <net/fib_notifier.h> 48 49 #include "fib_lookup.h" 50 51 static DEFINE_SPINLOCK(fib_info_lock); 52 static struct hlist_head *fib_info_hash; 53 static struct hlist_head *fib_info_laddrhash; 54 static unsigned int fib_info_hash_size; 55 static unsigned int fib_info_cnt; 56 57 #define DEVINDEX_HASHBITS 8 58 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 59 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 60 61 #ifdef CONFIG_IP_ROUTE_MULTIPATH 62 63 #define for_nexthops(fi) { \ 64 int nhsel; const struct fib_nh *nh; \ 65 for (nhsel = 0, nh = (fi)->fib_nh; \ 66 nhsel < (fi)->fib_nhs; \ 67 nh++, nhsel++) 68 69 #define change_nexthops(fi) { \ 70 int nhsel; struct fib_nh *nexthop_nh; \ 71 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 72 nhsel < (fi)->fib_nhs; \ 73 nexthop_nh++, nhsel++) 74 75 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 76 77 /* Hope, that gcc will optimize it to get rid of dummy loop */ 78 79 #define for_nexthops(fi) { \ 80 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ 81 for (nhsel = 0; nhsel < 1; nhsel++) 82 83 #define change_nexthops(fi) { \ 84 int nhsel; \ 85 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ 86 for (nhsel = 0; nhsel < 1; nhsel++) 87 88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 89 90 #define endfor_nexthops(fi) } 91 92 93 const struct fib_prop fib_props[RTN_MAX + 1] = { 94 [RTN_UNSPEC] = { 95 .error = 0, 96 .scope = RT_SCOPE_NOWHERE, 97 }, 98 [RTN_UNICAST] = { 99 .error = 0, 100 .scope = RT_SCOPE_UNIVERSE, 101 }, 102 [RTN_LOCAL] = { 103 .error = 0, 104 .scope = RT_SCOPE_HOST, 105 }, 106 [RTN_BROADCAST] = { 107 .error = 0, 108 .scope = RT_SCOPE_LINK, 109 }, 110 [RTN_ANYCAST] = { 111 .error = 0, 112 .scope = RT_SCOPE_LINK, 113 }, 114 [RTN_MULTICAST] = { 115 .error = 0, 116 .scope = RT_SCOPE_UNIVERSE, 117 }, 118 [RTN_BLACKHOLE] = { 119 .error = -EINVAL, 120 .scope = RT_SCOPE_UNIVERSE, 121 }, 122 [RTN_UNREACHABLE] = { 123 .error = -EHOSTUNREACH, 124 .scope = RT_SCOPE_UNIVERSE, 125 }, 126 [RTN_PROHIBIT] = { 127 .error = -EACCES, 128 .scope = RT_SCOPE_UNIVERSE, 129 }, 130 [RTN_THROW] = { 131 .error = -EAGAIN, 132 .scope = RT_SCOPE_UNIVERSE, 133 }, 134 [RTN_NAT] = { 135 .error = -EINVAL, 136 .scope = RT_SCOPE_NOWHERE, 137 }, 138 [RTN_XRESOLVE] = { 139 .error = -EINVAL, 140 .scope = RT_SCOPE_NOWHERE, 141 }, 142 }; 143 144 static void rt_fibinfo_free(struct rtable __rcu **rtp) 145 { 146 struct rtable *rt = rcu_dereference_protected(*rtp, 1); 147 148 if (!rt) 149 return; 150 151 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); 152 * because we waited an RCU grace period before calling 153 * free_fib_info_rcu() 154 */ 155 156 dst_dev_put(&rt->dst); 157 dst_release_immediate(&rt->dst); 158 } 159 160 static void free_nh_exceptions(struct fib_nh *nh) 161 { 162 struct fnhe_hash_bucket *hash; 163 int i; 164 165 hash = rcu_dereference_protected(nh->nh_exceptions, 1); 166 if (!hash) 167 return; 168 for (i = 0; i < FNHE_HASH_SIZE; i++) { 169 struct fib_nh_exception *fnhe; 170 171 fnhe = rcu_dereference_protected(hash[i].chain, 1); 172 while (fnhe) { 173 struct fib_nh_exception *next; 174 175 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 176 177 rt_fibinfo_free(&fnhe->fnhe_rth_input); 178 rt_fibinfo_free(&fnhe->fnhe_rth_output); 179 180 kfree(fnhe); 181 182 fnhe = next; 183 } 184 } 185 kfree(hash); 186 } 187 188 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 189 { 190 int cpu; 191 192 if (!rtp) 193 return; 194 195 for_each_possible_cpu(cpu) { 196 struct rtable *rt; 197 198 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 199 if (rt) { 200 dst_dev_put(&rt->dst); 201 dst_release_immediate(&rt->dst); 202 } 203 } 204 free_percpu(rtp); 205 } 206 207 /* Release a nexthop info record */ 208 static void free_fib_info_rcu(struct rcu_head *head) 209 { 210 struct fib_info *fi = container_of(head, struct fib_info, rcu); 211 struct dst_metrics *m; 212 213 change_nexthops(fi) { 214 if (nexthop_nh->nh_dev) 215 dev_put(nexthop_nh->nh_dev); 216 lwtstate_put(nexthop_nh->nh_lwtstate); 217 free_nh_exceptions(nexthop_nh); 218 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 219 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 220 } endfor_nexthops(fi); 221 222 m = fi->fib_metrics; 223 if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt)) 224 kfree(m); 225 kfree(fi); 226 } 227 228 void free_fib_info(struct fib_info *fi) 229 { 230 if (fi->fib_dead == 0) { 231 pr_warn("Freeing alive fib_info %p\n", fi); 232 return; 233 } 234 fib_info_cnt--; 235 #ifdef CONFIG_IP_ROUTE_CLASSID 236 change_nexthops(fi) { 237 if (nexthop_nh->nh_tclassid) 238 fi->fib_net->ipv4.fib_num_tclassid_users--; 239 } endfor_nexthops(fi); 240 #endif 241 call_rcu(&fi->rcu, free_fib_info_rcu); 242 } 243 EXPORT_SYMBOL_GPL(free_fib_info); 244 245 void fib_release_info(struct fib_info *fi) 246 { 247 spin_lock_bh(&fib_info_lock); 248 if (fi && --fi->fib_treeref == 0) { 249 hlist_del(&fi->fib_hash); 250 if (fi->fib_prefsrc) 251 hlist_del(&fi->fib_lhash); 252 change_nexthops(fi) { 253 if (!nexthop_nh->nh_dev) 254 continue; 255 hlist_del(&nexthop_nh->nh_hash); 256 } endfor_nexthops(fi) 257 fi->fib_dead = 1; 258 fib_info_put(fi); 259 } 260 spin_unlock_bh(&fib_info_lock); 261 } 262 263 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 264 { 265 const struct fib_nh *onh = ofi->fib_nh; 266 267 for_nexthops(fi) { 268 if (nh->nh_oif != onh->nh_oif || 269 nh->nh_gw != onh->nh_gw || 270 nh->nh_scope != onh->nh_scope || 271 #ifdef CONFIG_IP_ROUTE_MULTIPATH 272 nh->nh_weight != onh->nh_weight || 273 #endif 274 #ifdef CONFIG_IP_ROUTE_CLASSID 275 nh->nh_tclassid != onh->nh_tclassid || 276 #endif 277 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) || 278 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK)) 279 return -1; 280 onh++; 281 } endfor_nexthops(fi); 282 return 0; 283 } 284 285 static inline unsigned int fib_devindex_hashfn(unsigned int val) 286 { 287 unsigned int mask = DEVINDEX_HASHSIZE - 1; 288 289 return (val ^ 290 (val >> DEVINDEX_HASHBITS) ^ 291 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 292 } 293 294 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 295 { 296 unsigned int mask = (fib_info_hash_size - 1); 297 unsigned int val = fi->fib_nhs; 298 299 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 300 val ^= (__force u32)fi->fib_prefsrc; 301 val ^= fi->fib_priority; 302 for_nexthops(fi) { 303 val ^= fib_devindex_hashfn(nh->nh_oif); 304 } endfor_nexthops(fi) 305 306 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 307 } 308 309 static struct fib_info *fib_find_info(const struct fib_info *nfi) 310 { 311 struct hlist_head *head; 312 struct fib_info *fi; 313 unsigned int hash; 314 315 hash = fib_info_hashfn(nfi); 316 head = &fib_info_hash[hash]; 317 318 hlist_for_each_entry(fi, head, fib_hash) { 319 if (!net_eq(fi->fib_net, nfi->fib_net)) 320 continue; 321 if (fi->fib_nhs != nfi->fib_nhs) 322 continue; 323 if (nfi->fib_protocol == fi->fib_protocol && 324 nfi->fib_scope == fi->fib_scope && 325 nfi->fib_prefsrc == fi->fib_prefsrc && 326 nfi->fib_priority == fi->fib_priority && 327 nfi->fib_type == fi->fib_type && 328 memcmp(nfi->fib_metrics, fi->fib_metrics, 329 sizeof(u32) * RTAX_MAX) == 0 && 330 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && 331 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 332 return fi; 333 } 334 335 return NULL; 336 } 337 338 /* Check, that the gateway is already configured. 339 * Used only by redirect accept routine. 340 */ 341 int ip_fib_check_default(__be32 gw, struct net_device *dev) 342 { 343 struct hlist_head *head; 344 struct fib_nh *nh; 345 unsigned int hash; 346 347 spin_lock(&fib_info_lock); 348 349 hash = fib_devindex_hashfn(dev->ifindex); 350 head = &fib_info_devhash[hash]; 351 hlist_for_each_entry(nh, head, nh_hash) { 352 if (nh->nh_dev == dev && 353 nh->nh_gw == gw && 354 !(nh->nh_flags & RTNH_F_DEAD)) { 355 spin_unlock(&fib_info_lock); 356 return 0; 357 } 358 } 359 360 spin_unlock(&fib_info_lock); 361 362 return -1; 363 } 364 365 static inline size_t fib_nlmsg_size(struct fib_info *fi) 366 { 367 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 368 + nla_total_size(4) /* RTA_TABLE */ 369 + nla_total_size(4) /* RTA_DST */ 370 + nla_total_size(4) /* RTA_PRIORITY */ 371 + nla_total_size(4) /* RTA_PREFSRC */ 372 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ 373 374 /* space for nested metrics */ 375 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 376 377 if (fi->fib_nhs) { 378 size_t nh_encapsize = 0; 379 /* Also handles the special case fib_nhs == 1 */ 380 381 /* each nexthop is packed in an attribute */ 382 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 383 384 /* may contain flow and gateway attribute */ 385 nhsize += 2 * nla_total_size(4); 386 387 /* grab encap info */ 388 for_nexthops(fi) { 389 if (nh->nh_lwtstate) { 390 /* RTA_ENCAP_TYPE */ 391 nh_encapsize += lwtunnel_get_encap_size( 392 nh->nh_lwtstate); 393 /* RTA_ENCAP */ 394 nh_encapsize += nla_total_size(2); 395 } 396 } endfor_nexthops(fi); 397 398 /* all nexthops are packed in a nested attribute */ 399 payload += nla_total_size((fi->fib_nhs * nhsize) + 400 nh_encapsize); 401 402 } 403 404 return payload; 405 } 406 407 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 408 int dst_len, u32 tb_id, const struct nl_info *info, 409 unsigned int nlm_flags) 410 { 411 struct sk_buff *skb; 412 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 413 int err = -ENOBUFS; 414 415 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 416 if (!skb) 417 goto errout; 418 419 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 420 fa->fa_type, key, dst_len, 421 fa->fa_tos, fa->fa_info, nlm_flags); 422 if (err < 0) { 423 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 424 WARN_ON(err == -EMSGSIZE); 425 kfree_skb(skb); 426 goto errout; 427 } 428 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 429 info->nlh, GFP_KERNEL); 430 return; 431 errout: 432 if (err < 0) 433 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 434 } 435 436 static int fib_detect_death(struct fib_info *fi, int order, 437 struct fib_info **last_resort, int *last_idx, 438 int dflt) 439 { 440 struct neighbour *n; 441 int state = NUD_NONE; 442 443 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); 444 if (n) { 445 state = n->nud_state; 446 neigh_release(n); 447 } else { 448 return 0; 449 } 450 if (state == NUD_REACHABLE) 451 return 0; 452 if ((state & NUD_VALID) && order != dflt) 453 return 0; 454 if ((state & NUD_VALID) || 455 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { 456 *last_resort = fi; 457 *last_idx = order; 458 } 459 return 1; 460 } 461 462 #ifdef CONFIG_IP_ROUTE_MULTIPATH 463 464 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 465 struct netlink_ext_ack *extack) 466 { 467 int nhs = 0; 468 469 while (rtnh_ok(rtnh, remaining)) { 470 nhs++; 471 rtnh = rtnh_next(rtnh, &remaining); 472 } 473 474 /* leftover implies invalid nexthop configuration, discard it */ 475 if (remaining > 0) { 476 NL_SET_ERR_MSG(extack, 477 "Invalid nexthop configuration - extra data after nexthops"); 478 nhs = 0; 479 } 480 481 return nhs; 482 } 483 484 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 485 int remaining, struct fib_config *cfg, 486 struct netlink_ext_ack *extack) 487 { 488 int ret; 489 490 change_nexthops(fi) { 491 int attrlen; 492 493 if (!rtnh_ok(rtnh, remaining)) { 494 NL_SET_ERR_MSG(extack, 495 "Invalid nexthop configuration - extra data after nexthop"); 496 return -EINVAL; 497 } 498 499 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 500 NL_SET_ERR_MSG(extack, 501 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); 502 return -EINVAL; 503 } 504 505 nexthop_nh->nh_flags = 506 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 507 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 508 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 509 510 attrlen = rtnh_attrlen(rtnh); 511 if (attrlen > 0) { 512 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 513 514 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 515 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0; 516 #ifdef CONFIG_IP_ROUTE_CLASSID 517 nla = nla_find(attrs, attrlen, RTA_FLOW); 518 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 519 if (nexthop_nh->nh_tclassid) 520 fi->fib_net->ipv4.fib_num_tclassid_users++; 521 #endif 522 nla = nla_find(attrs, attrlen, RTA_ENCAP); 523 if (nla) { 524 struct lwtunnel_state *lwtstate; 525 struct nlattr *nla_entype; 526 527 nla_entype = nla_find(attrs, attrlen, 528 RTA_ENCAP_TYPE); 529 if (!nla_entype) { 530 NL_SET_BAD_ATTR(extack, nla); 531 NL_SET_ERR_MSG(extack, 532 "Encap type is missing"); 533 goto err_inval; 534 } 535 536 ret = lwtunnel_build_state(nla_get_u16( 537 nla_entype), 538 nla, AF_INET, cfg, 539 &lwtstate, extack); 540 if (ret) 541 goto errout; 542 nexthop_nh->nh_lwtstate = 543 lwtstate_get(lwtstate); 544 } 545 } 546 547 rtnh = rtnh_next(rtnh, &remaining); 548 } endfor_nexthops(fi); 549 550 return 0; 551 552 err_inval: 553 ret = -EINVAL; 554 555 errout: 556 return ret; 557 } 558 559 static void fib_rebalance(struct fib_info *fi) 560 { 561 int total; 562 int w; 563 struct in_device *in_dev; 564 565 if (fi->fib_nhs < 2) 566 return; 567 568 total = 0; 569 for_nexthops(fi) { 570 if (nh->nh_flags & RTNH_F_DEAD) 571 continue; 572 573 in_dev = __in_dev_get_rtnl(nh->nh_dev); 574 575 if (in_dev && 576 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 577 nh->nh_flags & RTNH_F_LINKDOWN) 578 continue; 579 580 total += nh->nh_weight; 581 } endfor_nexthops(fi); 582 583 w = 0; 584 change_nexthops(fi) { 585 int upper_bound; 586 587 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev); 588 589 if (nexthop_nh->nh_flags & RTNH_F_DEAD) { 590 upper_bound = -1; 591 } else if (in_dev && 592 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 593 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) { 594 upper_bound = -1; 595 } else { 596 w += nexthop_nh->nh_weight; 597 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, 598 total) - 1; 599 } 600 601 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound); 602 } endfor_nexthops(fi); 603 } 604 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 605 606 #define fib_rebalance(fi) do { } while (0) 607 608 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 609 610 static int fib_encap_match(u16 encap_type, 611 struct nlattr *encap, 612 const struct fib_nh *nh, 613 const struct fib_config *cfg, 614 struct netlink_ext_ack *extack) 615 { 616 struct lwtunnel_state *lwtstate; 617 int ret, result = 0; 618 619 if (encap_type == LWTUNNEL_ENCAP_NONE) 620 return 0; 621 622 ret = lwtunnel_build_state(encap_type, encap, AF_INET, 623 cfg, &lwtstate, extack); 624 if (!ret) { 625 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 626 lwtstate_free(lwtstate); 627 } 628 629 return result; 630 } 631 632 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, 633 struct netlink_ext_ack *extack) 634 { 635 #ifdef CONFIG_IP_ROUTE_MULTIPATH 636 struct rtnexthop *rtnh; 637 int remaining; 638 #endif 639 640 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 641 return 1; 642 643 if (cfg->fc_oif || cfg->fc_gw) { 644 if (cfg->fc_encap) { 645 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap, 646 fi->fib_nh, cfg, extack)) 647 return 1; 648 } 649 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 650 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 651 return 0; 652 return 1; 653 } 654 655 #ifdef CONFIG_IP_ROUTE_MULTIPATH 656 if (!cfg->fc_mp) 657 return 0; 658 659 rtnh = cfg->fc_mp; 660 remaining = cfg->fc_mp_len; 661 662 for_nexthops(fi) { 663 int attrlen; 664 665 if (!rtnh_ok(rtnh, remaining)) 666 return -EINVAL; 667 668 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 669 return 1; 670 671 attrlen = rtnh_attrlen(rtnh); 672 if (attrlen > 0) { 673 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 674 675 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 676 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 677 return 1; 678 #ifdef CONFIG_IP_ROUTE_CLASSID 679 nla = nla_find(attrs, attrlen, RTA_FLOW); 680 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 681 return 1; 682 #endif 683 } 684 685 rtnh = rtnh_next(rtnh, &remaining); 686 } endfor_nexthops(fi); 687 #endif 688 return 0; 689 } 690 691 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 692 { 693 struct nlattr *nla; 694 int remaining; 695 696 if (!cfg->fc_mx) 697 return true; 698 699 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 700 int type = nla_type(nla); 701 u32 val; 702 703 if (!type) 704 continue; 705 if (type > RTAX_MAX) 706 return false; 707 708 if (type == RTAX_CC_ALGO) { 709 char tmp[TCP_CA_NAME_MAX]; 710 bool ecn_ca = false; 711 712 nla_strlcpy(tmp, nla, sizeof(tmp)); 713 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 714 } else { 715 val = nla_get_u32(nla); 716 } 717 718 if (fi->fib_metrics->metrics[type - 1] != val) 719 return false; 720 } 721 722 return true; 723 } 724 725 726 /* 727 * Picture 728 * ------- 729 * 730 * Semantics of nexthop is very messy by historical reasons. 731 * We have to take into account, that: 732 * a) gateway can be actually local interface address, 733 * so that gatewayed route is direct. 734 * b) gateway must be on-link address, possibly 735 * described not by an ifaddr, but also by a direct route. 736 * c) If both gateway and interface are specified, they should not 737 * contradict. 738 * d) If we use tunnel routes, gateway could be not on-link. 739 * 740 * Attempt to reconcile all of these (alas, self-contradictory) conditions 741 * results in pretty ugly and hairy code with obscure logic. 742 * 743 * I chose to generalized it instead, so that the size 744 * of code does not increase practically, but it becomes 745 * much more general. 746 * Every prefix is assigned a "scope" value: "host" is local address, 747 * "link" is direct route, 748 * [ ... "site" ... "interior" ... ] 749 * and "universe" is true gateway route with global meaning. 750 * 751 * Every prefix refers to a set of "nexthop"s (gw, oif), 752 * where gw must have narrower scope. This recursion stops 753 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 754 * which means that gw is forced to be on link. 755 * 756 * Code is still hairy, but now it is apparently logically 757 * consistent and very flexible. F.e. as by-product it allows 758 * to co-exists in peace independent exterior and interior 759 * routing processes. 760 * 761 * Normally it looks as following. 762 * 763 * {universe prefix} -> (gw, oif) [scope link] 764 * | 765 * |-> {link prefix} -> (gw, oif) [scope local] 766 * | 767 * |-> {local prefix} (terminal node) 768 */ 769 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh, 770 struct netlink_ext_ack *extack) 771 { 772 int err = 0; 773 struct net *net; 774 struct net_device *dev; 775 776 net = cfg->fc_nlinfo.nl_net; 777 if (nh->nh_gw) { 778 struct fib_result res; 779 780 if (nh->nh_flags & RTNH_F_ONLINK) { 781 unsigned int addr_type; 782 783 if (cfg->fc_scope >= RT_SCOPE_LINK) { 784 NL_SET_ERR_MSG(extack, 785 "Nexthop has invalid scope"); 786 return -EINVAL; 787 } 788 dev = __dev_get_by_index(net, nh->nh_oif); 789 if (!dev) 790 return -ENODEV; 791 if (!(dev->flags & IFF_UP)) { 792 NL_SET_ERR_MSG(extack, 793 "Nexthop device is not up"); 794 return -ENETDOWN; 795 } 796 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 797 if (addr_type != RTN_UNICAST) { 798 NL_SET_ERR_MSG(extack, 799 "Nexthop has invalid gateway"); 800 return -EINVAL; 801 } 802 if (!netif_carrier_ok(dev)) 803 nh->nh_flags |= RTNH_F_LINKDOWN; 804 nh->nh_dev = dev; 805 dev_hold(dev); 806 nh->nh_scope = RT_SCOPE_LINK; 807 return 0; 808 } 809 rcu_read_lock(); 810 { 811 struct fib_table *tbl = NULL; 812 struct flowi4 fl4 = { 813 .daddr = nh->nh_gw, 814 .flowi4_scope = cfg->fc_scope + 1, 815 .flowi4_oif = nh->nh_oif, 816 .flowi4_iif = LOOPBACK_IFINDEX, 817 }; 818 819 /* It is not necessary, but requires a bit of thinking */ 820 if (fl4.flowi4_scope < RT_SCOPE_LINK) 821 fl4.flowi4_scope = RT_SCOPE_LINK; 822 823 if (cfg->fc_table) 824 tbl = fib_get_table(net, cfg->fc_table); 825 826 if (tbl) 827 err = fib_table_lookup(tbl, &fl4, &res, 828 FIB_LOOKUP_IGNORE_LINKSTATE | 829 FIB_LOOKUP_NOREF); 830 831 /* on error or if no table given do full lookup. This 832 * is needed for example when nexthops are in the local 833 * table rather than the given table 834 */ 835 if (!tbl || err) { 836 err = fib_lookup(net, &fl4, &res, 837 FIB_LOOKUP_IGNORE_LINKSTATE); 838 } 839 840 if (err) { 841 NL_SET_ERR_MSG(extack, 842 "Nexthop has invalid gateway"); 843 rcu_read_unlock(); 844 return err; 845 } 846 } 847 err = -EINVAL; 848 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 849 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 850 goto out; 851 } 852 nh->nh_scope = res.scope; 853 nh->nh_oif = FIB_RES_OIF(res); 854 nh->nh_dev = dev = FIB_RES_DEV(res); 855 if (!dev) { 856 NL_SET_ERR_MSG(extack, 857 "No egress device for nexthop gateway"); 858 goto out; 859 } 860 dev_hold(dev); 861 if (!netif_carrier_ok(dev)) 862 nh->nh_flags |= RTNH_F_LINKDOWN; 863 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 864 } else { 865 struct in_device *in_dev; 866 867 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 868 NL_SET_ERR_MSG(extack, 869 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 870 return -EINVAL; 871 } 872 rcu_read_lock(); 873 err = -ENODEV; 874 in_dev = inetdev_by_index(net, nh->nh_oif); 875 if (!in_dev) 876 goto out; 877 err = -ENETDOWN; 878 if (!(in_dev->dev->flags & IFF_UP)) { 879 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 880 goto out; 881 } 882 nh->nh_dev = in_dev->dev; 883 dev_hold(nh->nh_dev); 884 nh->nh_scope = RT_SCOPE_HOST; 885 if (!netif_carrier_ok(nh->nh_dev)) 886 nh->nh_flags |= RTNH_F_LINKDOWN; 887 err = 0; 888 } 889 out: 890 rcu_read_unlock(); 891 return err; 892 } 893 894 static inline unsigned int fib_laddr_hashfn(__be32 val) 895 { 896 unsigned int mask = (fib_info_hash_size - 1); 897 898 return ((__force u32)val ^ 899 ((__force u32)val >> 7) ^ 900 ((__force u32)val >> 14)) & mask; 901 } 902 903 static struct hlist_head *fib_info_hash_alloc(int bytes) 904 { 905 if (bytes <= PAGE_SIZE) 906 return kzalloc(bytes, GFP_KERNEL); 907 else 908 return (struct hlist_head *) 909 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 910 get_order(bytes)); 911 } 912 913 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 914 { 915 if (!hash) 916 return; 917 918 if (bytes <= PAGE_SIZE) 919 kfree(hash); 920 else 921 free_pages((unsigned long) hash, get_order(bytes)); 922 } 923 924 static void fib_info_hash_move(struct hlist_head *new_info_hash, 925 struct hlist_head *new_laddrhash, 926 unsigned int new_size) 927 { 928 struct hlist_head *old_info_hash, *old_laddrhash; 929 unsigned int old_size = fib_info_hash_size; 930 unsigned int i, bytes; 931 932 spin_lock_bh(&fib_info_lock); 933 old_info_hash = fib_info_hash; 934 old_laddrhash = fib_info_laddrhash; 935 fib_info_hash_size = new_size; 936 937 for (i = 0; i < old_size; i++) { 938 struct hlist_head *head = &fib_info_hash[i]; 939 struct hlist_node *n; 940 struct fib_info *fi; 941 942 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 943 struct hlist_head *dest; 944 unsigned int new_hash; 945 946 new_hash = fib_info_hashfn(fi); 947 dest = &new_info_hash[new_hash]; 948 hlist_add_head(&fi->fib_hash, dest); 949 } 950 } 951 fib_info_hash = new_info_hash; 952 953 for (i = 0; i < old_size; i++) { 954 struct hlist_head *lhead = &fib_info_laddrhash[i]; 955 struct hlist_node *n; 956 struct fib_info *fi; 957 958 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 959 struct hlist_head *ldest; 960 unsigned int new_hash; 961 962 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 963 ldest = &new_laddrhash[new_hash]; 964 hlist_add_head(&fi->fib_lhash, ldest); 965 } 966 } 967 fib_info_laddrhash = new_laddrhash; 968 969 spin_unlock_bh(&fib_info_lock); 970 971 bytes = old_size * sizeof(struct hlist_head *); 972 fib_info_hash_free(old_info_hash, bytes); 973 fib_info_hash_free(old_laddrhash, bytes); 974 } 975 976 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 977 { 978 nh->nh_saddr = inet_select_addr(nh->nh_dev, 979 nh->nh_gw, 980 nh->nh_parent->fib_scope); 981 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 982 983 return nh->nh_saddr; 984 } 985 986 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 987 { 988 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 989 fib_prefsrc != cfg->fc_dst) { 990 u32 tb_id = cfg->fc_table; 991 int rc; 992 993 if (tb_id == RT_TABLE_MAIN) 994 tb_id = RT_TABLE_LOCAL; 995 996 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 997 fib_prefsrc, tb_id); 998 999 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1000 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1001 fib_prefsrc, RT_TABLE_LOCAL); 1002 } 1003 1004 if (rc != RTN_LOCAL) 1005 return false; 1006 } 1007 return true; 1008 } 1009 1010 static int 1011 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 1012 { 1013 bool ecn_ca = false; 1014 struct nlattr *nla; 1015 int remaining; 1016 1017 if (!cfg->fc_mx) 1018 return 0; 1019 1020 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1021 int type = nla_type(nla); 1022 u32 val; 1023 1024 if (!type) 1025 continue; 1026 if (type > RTAX_MAX) 1027 return -EINVAL; 1028 1029 if (type == RTAX_CC_ALGO) { 1030 char tmp[TCP_CA_NAME_MAX]; 1031 1032 nla_strlcpy(tmp, nla, sizeof(tmp)); 1033 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1034 if (val == TCP_CA_UNSPEC) 1035 return -EINVAL; 1036 } else { 1037 val = nla_get_u32(nla); 1038 } 1039 if (type == RTAX_ADVMSS && val > 65535 - 40) 1040 val = 65535 - 40; 1041 if (type == RTAX_MTU && val > 65535 - 15) 1042 val = 65535 - 15; 1043 if (type == RTAX_HOPLIMIT && val > 255) 1044 val = 255; 1045 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 1046 return -EINVAL; 1047 fi->fib_metrics->metrics[type - 1] = val; 1048 } 1049 1050 if (ecn_ca) 1051 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 1052 1053 return 0; 1054 } 1055 1056 struct fib_info *fib_create_info(struct fib_config *cfg, 1057 struct netlink_ext_ack *extack) 1058 { 1059 int err; 1060 struct fib_info *fi = NULL; 1061 struct fib_info *ofi; 1062 int nhs = 1; 1063 struct net *net = cfg->fc_nlinfo.nl_net; 1064 1065 if (cfg->fc_type > RTN_MAX) 1066 goto err_inval; 1067 1068 /* Fast check to catch the most weird cases */ 1069 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1070 NL_SET_ERR_MSG(extack, "Invalid scope"); 1071 goto err_inval; 1072 } 1073 1074 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1075 NL_SET_ERR_MSG(extack, 1076 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1077 goto err_inval; 1078 } 1079 1080 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1081 if (cfg->fc_mp) { 1082 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1083 if (nhs == 0) 1084 goto err_inval; 1085 } 1086 #endif 1087 1088 err = -ENOBUFS; 1089 if (fib_info_cnt >= fib_info_hash_size) { 1090 unsigned int new_size = fib_info_hash_size << 1; 1091 struct hlist_head *new_info_hash; 1092 struct hlist_head *new_laddrhash; 1093 unsigned int bytes; 1094 1095 if (!new_size) 1096 new_size = 16; 1097 bytes = new_size * sizeof(struct hlist_head *); 1098 new_info_hash = fib_info_hash_alloc(bytes); 1099 new_laddrhash = fib_info_hash_alloc(bytes); 1100 if (!new_info_hash || !new_laddrhash) { 1101 fib_info_hash_free(new_info_hash, bytes); 1102 fib_info_hash_free(new_laddrhash, bytes); 1103 } else 1104 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1105 1106 if (!fib_info_hash_size) 1107 goto failure; 1108 } 1109 1110 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1111 if (!fi) 1112 goto failure; 1113 if (cfg->fc_mx) { 1114 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL); 1115 if (unlikely(!fi->fib_metrics)) { 1116 kfree(fi); 1117 return ERR_PTR(err); 1118 } 1119 refcount_set(&fi->fib_metrics->refcnt, 1); 1120 } else { 1121 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics; 1122 } 1123 fib_info_cnt++; 1124 fi->fib_net = net; 1125 fi->fib_protocol = cfg->fc_protocol; 1126 fi->fib_scope = cfg->fc_scope; 1127 fi->fib_flags = cfg->fc_flags; 1128 fi->fib_priority = cfg->fc_priority; 1129 fi->fib_prefsrc = cfg->fc_prefsrc; 1130 fi->fib_type = cfg->fc_type; 1131 fi->fib_tb_id = cfg->fc_table; 1132 1133 fi->fib_nhs = nhs; 1134 change_nexthops(fi) { 1135 nexthop_nh->nh_parent = fi; 1136 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1137 if (!nexthop_nh->nh_pcpu_rth_output) 1138 goto failure; 1139 } endfor_nexthops(fi) 1140 1141 err = fib_convert_metrics(fi, cfg); 1142 if (err) 1143 goto failure; 1144 1145 if (cfg->fc_mp) { 1146 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1147 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); 1148 if (err != 0) 1149 goto failure; 1150 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) { 1151 NL_SET_ERR_MSG(extack, 1152 "Nexthop device index does not match RTA_OIF"); 1153 goto err_inval; 1154 } 1155 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) { 1156 NL_SET_ERR_MSG(extack, 1157 "Nexthop gateway does not match RTA_GATEWAY"); 1158 goto err_inval; 1159 } 1160 #ifdef CONFIG_IP_ROUTE_CLASSID 1161 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) { 1162 NL_SET_ERR_MSG(extack, 1163 "Nexthop class id does not match RTA_FLOW"); 1164 goto err_inval; 1165 } 1166 #endif 1167 #else 1168 NL_SET_ERR_MSG(extack, 1169 "Multipath support not enabled in kernel"); 1170 goto err_inval; 1171 #endif 1172 } else { 1173 struct fib_nh *nh = fi->fib_nh; 1174 1175 if (cfg->fc_encap) { 1176 struct lwtunnel_state *lwtstate; 1177 1178 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) { 1179 NL_SET_ERR_MSG(extack, 1180 "LWT encap type not specified"); 1181 goto err_inval; 1182 } 1183 err = lwtunnel_build_state(cfg->fc_encap_type, 1184 cfg->fc_encap, AF_INET, cfg, 1185 &lwtstate, extack); 1186 if (err) 1187 goto failure; 1188 1189 nh->nh_lwtstate = lwtstate_get(lwtstate); 1190 } 1191 nh->nh_oif = cfg->fc_oif; 1192 nh->nh_gw = cfg->fc_gw; 1193 nh->nh_flags = cfg->fc_flags; 1194 #ifdef CONFIG_IP_ROUTE_CLASSID 1195 nh->nh_tclassid = cfg->fc_flow; 1196 if (nh->nh_tclassid) 1197 fi->fib_net->ipv4.fib_num_tclassid_users++; 1198 #endif 1199 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1200 nh->nh_weight = 1; 1201 #endif 1202 } 1203 1204 if (fib_props[cfg->fc_type].error) { 1205 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) { 1206 NL_SET_ERR_MSG(extack, 1207 "Gateway, device and multipath can not be specified for this route type"); 1208 goto err_inval; 1209 } 1210 goto link_it; 1211 } else { 1212 switch (cfg->fc_type) { 1213 case RTN_UNICAST: 1214 case RTN_LOCAL: 1215 case RTN_BROADCAST: 1216 case RTN_ANYCAST: 1217 case RTN_MULTICAST: 1218 break; 1219 default: 1220 NL_SET_ERR_MSG(extack, "Invalid route type"); 1221 goto err_inval; 1222 } 1223 } 1224 1225 if (cfg->fc_scope > RT_SCOPE_HOST) { 1226 NL_SET_ERR_MSG(extack, "Invalid scope"); 1227 goto err_inval; 1228 } 1229 1230 if (cfg->fc_scope == RT_SCOPE_HOST) { 1231 struct fib_nh *nh = fi->fib_nh; 1232 1233 /* Local address is added. */ 1234 if (nhs != 1) { 1235 NL_SET_ERR_MSG(extack, 1236 "Route with host scope can not have multiple nexthops"); 1237 goto err_inval; 1238 } 1239 if (nh->nh_gw) { 1240 NL_SET_ERR_MSG(extack, 1241 "Route with host scope can not have a gateway"); 1242 goto err_inval; 1243 } 1244 nh->nh_scope = RT_SCOPE_NOWHERE; 1245 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1246 err = -ENODEV; 1247 if (!nh->nh_dev) 1248 goto failure; 1249 } else { 1250 int linkdown = 0; 1251 1252 change_nexthops(fi) { 1253 err = fib_check_nh(cfg, nexthop_nh, extack); 1254 if (err != 0) 1255 goto failure; 1256 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1257 linkdown++; 1258 } endfor_nexthops(fi) 1259 if (linkdown == fi->fib_nhs) 1260 fi->fib_flags |= RTNH_F_LINKDOWN; 1261 } 1262 1263 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1264 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1265 goto err_inval; 1266 } 1267 1268 change_nexthops(fi) { 1269 fib_info_update_nh_saddr(net, nexthop_nh); 1270 } endfor_nexthops(fi) 1271 1272 fib_rebalance(fi); 1273 1274 link_it: 1275 ofi = fib_find_info(fi); 1276 if (ofi) { 1277 fi->fib_dead = 1; 1278 free_fib_info(fi); 1279 ofi->fib_treeref++; 1280 return ofi; 1281 } 1282 1283 fi->fib_treeref++; 1284 refcount_set(&fi->fib_clntref, 1); 1285 spin_lock_bh(&fib_info_lock); 1286 hlist_add_head(&fi->fib_hash, 1287 &fib_info_hash[fib_info_hashfn(fi)]); 1288 if (fi->fib_prefsrc) { 1289 struct hlist_head *head; 1290 1291 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1292 hlist_add_head(&fi->fib_lhash, head); 1293 } 1294 change_nexthops(fi) { 1295 struct hlist_head *head; 1296 unsigned int hash; 1297 1298 if (!nexthop_nh->nh_dev) 1299 continue; 1300 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1301 head = &fib_info_devhash[hash]; 1302 hlist_add_head(&nexthop_nh->nh_hash, head); 1303 } endfor_nexthops(fi) 1304 spin_unlock_bh(&fib_info_lock); 1305 return fi; 1306 1307 err_inval: 1308 err = -EINVAL; 1309 1310 failure: 1311 if (fi) { 1312 fi->fib_dead = 1; 1313 free_fib_info(fi); 1314 } 1315 1316 return ERR_PTR(err); 1317 } 1318 1319 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1320 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1321 struct fib_info *fi, unsigned int flags) 1322 { 1323 struct nlmsghdr *nlh; 1324 struct rtmsg *rtm; 1325 1326 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1327 if (!nlh) 1328 return -EMSGSIZE; 1329 1330 rtm = nlmsg_data(nlh); 1331 rtm->rtm_family = AF_INET; 1332 rtm->rtm_dst_len = dst_len; 1333 rtm->rtm_src_len = 0; 1334 rtm->rtm_tos = tos; 1335 if (tb_id < 256) 1336 rtm->rtm_table = tb_id; 1337 else 1338 rtm->rtm_table = RT_TABLE_COMPAT; 1339 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1340 goto nla_put_failure; 1341 rtm->rtm_type = type; 1342 rtm->rtm_flags = fi->fib_flags; 1343 rtm->rtm_scope = fi->fib_scope; 1344 rtm->rtm_protocol = fi->fib_protocol; 1345 1346 if (rtm->rtm_dst_len && 1347 nla_put_in_addr(skb, RTA_DST, dst)) 1348 goto nla_put_failure; 1349 if (fi->fib_priority && 1350 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1351 goto nla_put_failure; 1352 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1353 goto nla_put_failure; 1354 1355 if (fi->fib_prefsrc && 1356 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1357 goto nla_put_failure; 1358 if (fi->fib_nhs == 1) { 1359 if (fi->fib_nh->nh_gw && 1360 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1361 goto nla_put_failure; 1362 if (fi->fib_nh->nh_oif && 1363 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1364 goto nla_put_failure; 1365 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1366 struct in_device *in_dev; 1367 1368 rcu_read_lock(); 1369 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev); 1370 if (in_dev && 1371 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1372 rtm->rtm_flags |= RTNH_F_DEAD; 1373 rcu_read_unlock(); 1374 } 1375 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD) 1376 rtm->rtm_flags |= RTNH_F_OFFLOAD; 1377 #ifdef CONFIG_IP_ROUTE_CLASSID 1378 if (fi->fib_nh[0].nh_tclassid && 1379 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1380 goto nla_put_failure; 1381 #endif 1382 if (fi->fib_nh->nh_lwtstate && 1383 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0) 1384 goto nla_put_failure; 1385 } 1386 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1387 if (fi->fib_nhs > 1) { 1388 struct rtnexthop *rtnh; 1389 struct nlattr *mp; 1390 1391 mp = nla_nest_start(skb, RTA_MULTIPATH); 1392 if (!mp) 1393 goto nla_put_failure; 1394 1395 for_nexthops(fi) { 1396 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1397 if (!rtnh) 1398 goto nla_put_failure; 1399 1400 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1401 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1402 struct in_device *in_dev; 1403 1404 rcu_read_lock(); 1405 in_dev = __in_dev_get_rcu(nh->nh_dev); 1406 if (in_dev && 1407 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1408 rtnh->rtnh_flags |= RTNH_F_DEAD; 1409 rcu_read_unlock(); 1410 } 1411 rtnh->rtnh_hops = nh->nh_weight - 1; 1412 rtnh->rtnh_ifindex = nh->nh_oif; 1413 1414 if (nh->nh_gw && 1415 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1416 goto nla_put_failure; 1417 #ifdef CONFIG_IP_ROUTE_CLASSID 1418 if (nh->nh_tclassid && 1419 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1420 goto nla_put_failure; 1421 #endif 1422 if (nh->nh_lwtstate && 1423 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0) 1424 goto nla_put_failure; 1425 1426 /* length of rtnetlink header + attributes */ 1427 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1428 } endfor_nexthops(fi); 1429 1430 nla_nest_end(skb, mp); 1431 } 1432 #endif 1433 nlmsg_end(skb, nlh); 1434 return 0; 1435 1436 nla_put_failure: 1437 nlmsg_cancel(skb, nlh); 1438 return -EMSGSIZE; 1439 } 1440 1441 /* 1442 * Update FIB if: 1443 * - local address disappeared -> we must delete all the entries 1444 * referring to it. 1445 * - device went down -> we must shutdown all nexthops going via it. 1446 */ 1447 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1448 { 1449 int ret = 0; 1450 unsigned int hash = fib_laddr_hashfn(local); 1451 struct hlist_head *head = &fib_info_laddrhash[hash]; 1452 struct net *net = dev_net(dev); 1453 int tb_id = l3mdev_fib_table(dev); 1454 struct fib_info *fi; 1455 1456 if (!fib_info_laddrhash || local == 0) 1457 return 0; 1458 1459 hlist_for_each_entry(fi, head, fib_lhash) { 1460 if (!net_eq(fi->fib_net, net) || 1461 fi->fib_tb_id != tb_id) 1462 continue; 1463 if (fi->fib_prefsrc == local) { 1464 fi->fib_flags |= RTNH_F_DEAD; 1465 ret++; 1466 } 1467 } 1468 return ret; 1469 } 1470 1471 static int call_fib_nh_notifiers(struct fib_nh *fib_nh, 1472 enum fib_event_type event_type) 1473 { 1474 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev); 1475 struct fib_nh_notifier_info info = { 1476 .fib_nh = fib_nh, 1477 }; 1478 1479 switch (event_type) { 1480 case FIB_EVENT_NH_ADD: 1481 if (fib_nh->nh_flags & RTNH_F_DEAD) 1482 break; 1483 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1484 fib_nh->nh_flags & RTNH_F_LINKDOWN) 1485 break; 1486 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type, 1487 &info.info); 1488 case FIB_EVENT_NH_DEL: 1489 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1490 fib_nh->nh_flags & RTNH_F_LINKDOWN) || 1491 (fib_nh->nh_flags & RTNH_F_DEAD)) 1492 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), 1493 event_type, &info.info); 1494 default: 1495 break; 1496 } 1497 1498 return NOTIFY_DONE; 1499 } 1500 1501 /* Event force Flags Description 1502 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1503 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1504 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1505 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1506 */ 1507 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1508 { 1509 int ret = 0; 1510 int scope = RT_SCOPE_NOWHERE; 1511 struct fib_info *prev_fi = NULL; 1512 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1513 struct hlist_head *head = &fib_info_devhash[hash]; 1514 struct fib_nh *nh; 1515 1516 if (force) 1517 scope = -1; 1518 1519 hlist_for_each_entry(nh, head, nh_hash) { 1520 struct fib_info *fi = nh->nh_parent; 1521 int dead; 1522 1523 BUG_ON(!fi->fib_nhs); 1524 if (nh->nh_dev != dev || fi == prev_fi) 1525 continue; 1526 prev_fi = fi; 1527 dead = 0; 1528 change_nexthops(fi) { 1529 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1530 dead++; 1531 else if (nexthop_nh->nh_dev == dev && 1532 nexthop_nh->nh_scope != scope) { 1533 switch (event) { 1534 case NETDEV_DOWN: 1535 case NETDEV_UNREGISTER: 1536 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1537 /* fall through */ 1538 case NETDEV_CHANGE: 1539 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1540 break; 1541 } 1542 call_fib_nh_notifiers(nexthop_nh, 1543 FIB_EVENT_NH_DEL); 1544 dead++; 1545 } 1546 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1547 if (event == NETDEV_UNREGISTER && 1548 nexthop_nh->nh_dev == dev) { 1549 dead = fi->fib_nhs; 1550 break; 1551 } 1552 #endif 1553 } endfor_nexthops(fi) 1554 if (dead == fi->fib_nhs) { 1555 switch (event) { 1556 case NETDEV_DOWN: 1557 case NETDEV_UNREGISTER: 1558 fi->fib_flags |= RTNH_F_DEAD; 1559 /* fall through */ 1560 case NETDEV_CHANGE: 1561 fi->fib_flags |= RTNH_F_LINKDOWN; 1562 break; 1563 } 1564 ret++; 1565 } 1566 1567 fib_rebalance(fi); 1568 } 1569 1570 return ret; 1571 } 1572 1573 /* Must be invoked inside of an RCU protected region. */ 1574 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1575 { 1576 struct fib_info *fi = NULL, *last_resort = NULL; 1577 struct hlist_head *fa_head = res->fa_head; 1578 struct fib_table *tb = res->table; 1579 u8 slen = 32 - res->prefixlen; 1580 int order = -1, last_idx = -1; 1581 struct fib_alias *fa, *fa1 = NULL; 1582 u32 last_prio = res->fi->fib_priority; 1583 u8 last_tos = 0; 1584 1585 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1586 struct fib_info *next_fi = fa->fa_info; 1587 1588 if (fa->fa_slen != slen) 1589 continue; 1590 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1591 continue; 1592 if (fa->tb_id != tb->tb_id) 1593 continue; 1594 if (next_fi->fib_priority > last_prio && 1595 fa->fa_tos == last_tos) { 1596 if (last_tos) 1597 continue; 1598 break; 1599 } 1600 if (next_fi->fib_flags & RTNH_F_DEAD) 1601 continue; 1602 last_tos = fa->fa_tos; 1603 last_prio = next_fi->fib_priority; 1604 1605 if (next_fi->fib_scope != res->scope || 1606 fa->fa_type != RTN_UNICAST) 1607 continue; 1608 if (!next_fi->fib_nh[0].nh_gw || 1609 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1610 continue; 1611 1612 fib_alias_accessed(fa); 1613 1614 if (!fi) { 1615 if (next_fi != res->fi) 1616 break; 1617 fa1 = fa; 1618 } else if (!fib_detect_death(fi, order, &last_resort, 1619 &last_idx, fa1->fa_default)) { 1620 fib_result_assign(res, fi); 1621 fa1->fa_default = order; 1622 goto out; 1623 } 1624 fi = next_fi; 1625 order++; 1626 } 1627 1628 if (order <= 0 || !fi) { 1629 if (fa1) 1630 fa1->fa_default = -1; 1631 goto out; 1632 } 1633 1634 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1635 fa1->fa_default)) { 1636 fib_result_assign(res, fi); 1637 fa1->fa_default = order; 1638 goto out; 1639 } 1640 1641 if (last_idx >= 0) 1642 fib_result_assign(res, last_resort); 1643 fa1->fa_default = last_idx; 1644 out: 1645 return; 1646 } 1647 1648 /* 1649 * Dead device goes up. We wake up dead nexthops. 1650 * It takes sense only on multipath routes. 1651 */ 1652 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1653 { 1654 struct fib_info *prev_fi; 1655 unsigned int hash; 1656 struct hlist_head *head; 1657 struct fib_nh *nh; 1658 int ret; 1659 1660 if (!(dev->flags & IFF_UP)) 1661 return 0; 1662 1663 if (nh_flags & RTNH_F_DEAD) { 1664 unsigned int flags = dev_get_flags(dev); 1665 1666 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1667 nh_flags |= RTNH_F_LINKDOWN; 1668 } 1669 1670 prev_fi = NULL; 1671 hash = fib_devindex_hashfn(dev->ifindex); 1672 head = &fib_info_devhash[hash]; 1673 ret = 0; 1674 1675 hlist_for_each_entry(nh, head, nh_hash) { 1676 struct fib_info *fi = nh->nh_parent; 1677 int alive; 1678 1679 BUG_ON(!fi->fib_nhs); 1680 if (nh->nh_dev != dev || fi == prev_fi) 1681 continue; 1682 1683 prev_fi = fi; 1684 alive = 0; 1685 change_nexthops(fi) { 1686 if (!(nexthop_nh->nh_flags & nh_flags)) { 1687 alive++; 1688 continue; 1689 } 1690 if (!nexthop_nh->nh_dev || 1691 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1692 continue; 1693 if (nexthop_nh->nh_dev != dev || 1694 !__in_dev_get_rtnl(dev)) 1695 continue; 1696 alive++; 1697 nexthop_nh->nh_flags &= ~nh_flags; 1698 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 1699 } endfor_nexthops(fi) 1700 1701 if (alive > 0) { 1702 fi->fib_flags &= ~nh_flags; 1703 ret++; 1704 } 1705 1706 fib_rebalance(fi); 1707 } 1708 1709 return ret; 1710 } 1711 1712 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1713 static bool fib_good_nh(const struct fib_nh *nh) 1714 { 1715 int state = NUD_REACHABLE; 1716 1717 if (nh->nh_scope == RT_SCOPE_LINK) { 1718 struct neighbour *n; 1719 1720 rcu_read_lock_bh(); 1721 1722 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1723 (__force u32)nh->nh_gw); 1724 if (n) 1725 state = n->nud_state; 1726 1727 rcu_read_unlock_bh(); 1728 } 1729 1730 return !!(state & NUD_VALID); 1731 } 1732 1733 void fib_select_multipath(struct fib_result *res, int hash) 1734 { 1735 struct fib_info *fi = res->fi; 1736 struct net *net = fi->fib_net; 1737 bool first = false; 1738 1739 for_nexthops(fi) { 1740 if (hash > atomic_read(&nh->nh_upper_bound)) 1741 continue; 1742 1743 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1744 fib_good_nh(nh)) { 1745 res->nh_sel = nhsel; 1746 return; 1747 } 1748 if (!first) { 1749 res->nh_sel = nhsel; 1750 first = true; 1751 } 1752 } endfor_nexthops(fi); 1753 } 1754 #endif 1755 1756 void fib_select_path(struct net *net, struct fib_result *res, 1757 struct flowi4 *fl4, const struct sk_buff *skb) 1758 { 1759 bool oif_check; 1760 1761 oif_check = (fl4->flowi4_oif == 0 || 1762 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF); 1763 1764 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1765 if (res->fi->fib_nhs > 1 && oif_check) { 1766 int h = fib_multipath_hash(res->fi, fl4, skb); 1767 1768 fib_select_multipath(res, h); 1769 } 1770 else 1771 #endif 1772 if (!res->prefixlen && 1773 res->table->tb_num_default > 1 && 1774 res->type == RTN_UNICAST && oif_check) 1775 fib_select_default(fl4, res); 1776 1777 if (!fl4->saddr) 1778 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1779 } 1780 EXPORT_SYMBOL_GPL(fib_select_path); 1781