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 fi_val, 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 fi_val = fi->fib_metrics->metrics[type - 1]; 719 if (type == RTAX_FEATURES) 720 fi_val &= ~DST_FEATURE_ECN_CA; 721 722 if (fi_val != val) 723 return false; 724 } 725 726 return true; 727 } 728 729 730 /* 731 * Picture 732 * ------- 733 * 734 * Semantics of nexthop is very messy by historical reasons. 735 * We have to take into account, that: 736 * a) gateway can be actually local interface address, 737 * so that gatewayed route is direct. 738 * b) gateway must be on-link address, possibly 739 * described not by an ifaddr, but also by a direct route. 740 * c) If both gateway and interface are specified, they should not 741 * contradict. 742 * d) If we use tunnel routes, gateway could be not on-link. 743 * 744 * Attempt to reconcile all of these (alas, self-contradictory) conditions 745 * results in pretty ugly and hairy code with obscure logic. 746 * 747 * I chose to generalized it instead, so that the size 748 * of code does not increase practically, but it becomes 749 * much more general. 750 * Every prefix is assigned a "scope" value: "host" is local address, 751 * "link" is direct route, 752 * [ ... "site" ... "interior" ... ] 753 * and "universe" is true gateway route with global meaning. 754 * 755 * Every prefix refers to a set of "nexthop"s (gw, oif), 756 * where gw must have narrower scope. This recursion stops 757 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 758 * which means that gw is forced to be on link. 759 * 760 * Code is still hairy, but now it is apparently logically 761 * consistent and very flexible. F.e. as by-product it allows 762 * to co-exists in peace independent exterior and interior 763 * routing processes. 764 * 765 * Normally it looks as following. 766 * 767 * {universe prefix} -> (gw, oif) [scope link] 768 * | 769 * |-> {link prefix} -> (gw, oif) [scope local] 770 * | 771 * |-> {local prefix} (terminal node) 772 */ 773 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh, 774 struct netlink_ext_ack *extack) 775 { 776 int err = 0; 777 struct net *net; 778 struct net_device *dev; 779 780 net = cfg->fc_nlinfo.nl_net; 781 if (nh->nh_gw) { 782 struct fib_result res; 783 784 if (nh->nh_flags & RTNH_F_ONLINK) { 785 unsigned int addr_type; 786 787 if (cfg->fc_scope >= RT_SCOPE_LINK) { 788 NL_SET_ERR_MSG(extack, 789 "Nexthop has invalid scope"); 790 return -EINVAL; 791 } 792 dev = __dev_get_by_index(net, nh->nh_oif); 793 if (!dev) 794 return -ENODEV; 795 if (!(dev->flags & IFF_UP)) { 796 NL_SET_ERR_MSG(extack, 797 "Nexthop device is not up"); 798 return -ENETDOWN; 799 } 800 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 801 if (addr_type != RTN_UNICAST) { 802 NL_SET_ERR_MSG(extack, 803 "Nexthop has invalid gateway"); 804 return -EINVAL; 805 } 806 if (!netif_carrier_ok(dev)) 807 nh->nh_flags |= RTNH_F_LINKDOWN; 808 nh->nh_dev = dev; 809 dev_hold(dev); 810 nh->nh_scope = RT_SCOPE_LINK; 811 return 0; 812 } 813 rcu_read_lock(); 814 { 815 struct fib_table *tbl = NULL; 816 struct flowi4 fl4 = { 817 .daddr = nh->nh_gw, 818 .flowi4_scope = cfg->fc_scope + 1, 819 .flowi4_oif = nh->nh_oif, 820 .flowi4_iif = LOOPBACK_IFINDEX, 821 }; 822 823 /* It is not necessary, but requires a bit of thinking */ 824 if (fl4.flowi4_scope < RT_SCOPE_LINK) 825 fl4.flowi4_scope = RT_SCOPE_LINK; 826 827 if (cfg->fc_table) 828 tbl = fib_get_table(net, cfg->fc_table); 829 830 if (tbl) 831 err = fib_table_lookup(tbl, &fl4, &res, 832 FIB_LOOKUP_IGNORE_LINKSTATE | 833 FIB_LOOKUP_NOREF); 834 835 /* on error or if no table given do full lookup. This 836 * is needed for example when nexthops are in the local 837 * table rather than the given table 838 */ 839 if (!tbl || err) { 840 err = fib_lookup(net, &fl4, &res, 841 FIB_LOOKUP_IGNORE_LINKSTATE); 842 } 843 844 if (err) { 845 NL_SET_ERR_MSG(extack, 846 "Nexthop has invalid gateway"); 847 rcu_read_unlock(); 848 return err; 849 } 850 } 851 err = -EINVAL; 852 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 853 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 854 goto out; 855 } 856 nh->nh_scope = res.scope; 857 nh->nh_oif = FIB_RES_OIF(res); 858 nh->nh_dev = dev = FIB_RES_DEV(res); 859 if (!dev) { 860 NL_SET_ERR_MSG(extack, 861 "No egress device for nexthop gateway"); 862 goto out; 863 } 864 dev_hold(dev); 865 if (!netif_carrier_ok(dev)) 866 nh->nh_flags |= RTNH_F_LINKDOWN; 867 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 868 } else { 869 struct in_device *in_dev; 870 871 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 872 NL_SET_ERR_MSG(extack, 873 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 874 return -EINVAL; 875 } 876 rcu_read_lock(); 877 err = -ENODEV; 878 in_dev = inetdev_by_index(net, nh->nh_oif); 879 if (!in_dev) 880 goto out; 881 err = -ENETDOWN; 882 if (!(in_dev->dev->flags & IFF_UP)) { 883 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 884 goto out; 885 } 886 nh->nh_dev = in_dev->dev; 887 dev_hold(nh->nh_dev); 888 nh->nh_scope = RT_SCOPE_HOST; 889 if (!netif_carrier_ok(nh->nh_dev)) 890 nh->nh_flags |= RTNH_F_LINKDOWN; 891 err = 0; 892 } 893 out: 894 rcu_read_unlock(); 895 return err; 896 } 897 898 static inline unsigned int fib_laddr_hashfn(__be32 val) 899 { 900 unsigned int mask = (fib_info_hash_size - 1); 901 902 return ((__force u32)val ^ 903 ((__force u32)val >> 7) ^ 904 ((__force u32)val >> 14)) & mask; 905 } 906 907 static struct hlist_head *fib_info_hash_alloc(int bytes) 908 { 909 if (bytes <= PAGE_SIZE) 910 return kzalloc(bytes, GFP_KERNEL); 911 else 912 return (struct hlist_head *) 913 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 914 get_order(bytes)); 915 } 916 917 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 918 { 919 if (!hash) 920 return; 921 922 if (bytes <= PAGE_SIZE) 923 kfree(hash); 924 else 925 free_pages((unsigned long) hash, get_order(bytes)); 926 } 927 928 static void fib_info_hash_move(struct hlist_head *new_info_hash, 929 struct hlist_head *new_laddrhash, 930 unsigned int new_size) 931 { 932 struct hlist_head *old_info_hash, *old_laddrhash; 933 unsigned int old_size = fib_info_hash_size; 934 unsigned int i, bytes; 935 936 spin_lock_bh(&fib_info_lock); 937 old_info_hash = fib_info_hash; 938 old_laddrhash = fib_info_laddrhash; 939 fib_info_hash_size = new_size; 940 941 for (i = 0; i < old_size; i++) { 942 struct hlist_head *head = &fib_info_hash[i]; 943 struct hlist_node *n; 944 struct fib_info *fi; 945 946 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 947 struct hlist_head *dest; 948 unsigned int new_hash; 949 950 new_hash = fib_info_hashfn(fi); 951 dest = &new_info_hash[new_hash]; 952 hlist_add_head(&fi->fib_hash, dest); 953 } 954 } 955 fib_info_hash = new_info_hash; 956 957 for (i = 0; i < old_size; i++) { 958 struct hlist_head *lhead = &fib_info_laddrhash[i]; 959 struct hlist_node *n; 960 struct fib_info *fi; 961 962 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 963 struct hlist_head *ldest; 964 unsigned int new_hash; 965 966 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 967 ldest = &new_laddrhash[new_hash]; 968 hlist_add_head(&fi->fib_lhash, ldest); 969 } 970 } 971 fib_info_laddrhash = new_laddrhash; 972 973 spin_unlock_bh(&fib_info_lock); 974 975 bytes = old_size * sizeof(struct hlist_head *); 976 fib_info_hash_free(old_info_hash, bytes); 977 fib_info_hash_free(old_laddrhash, bytes); 978 } 979 980 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 981 { 982 nh->nh_saddr = inet_select_addr(nh->nh_dev, 983 nh->nh_gw, 984 nh->nh_parent->fib_scope); 985 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 986 987 return nh->nh_saddr; 988 } 989 990 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 991 { 992 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 993 fib_prefsrc != cfg->fc_dst) { 994 u32 tb_id = cfg->fc_table; 995 int rc; 996 997 if (tb_id == RT_TABLE_MAIN) 998 tb_id = RT_TABLE_LOCAL; 999 1000 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1001 fib_prefsrc, tb_id); 1002 1003 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1004 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1005 fib_prefsrc, RT_TABLE_LOCAL); 1006 } 1007 1008 if (rc != RTN_LOCAL) 1009 return false; 1010 } 1011 return true; 1012 } 1013 1014 static int 1015 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 1016 { 1017 bool ecn_ca = false; 1018 struct nlattr *nla; 1019 int remaining; 1020 1021 if (!cfg->fc_mx) 1022 return 0; 1023 1024 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1025 int type = nla_type(nla); 1026 u32 val; 1027 1028 if (!type) 1029 continue; 1030 if (type > RTAX_MAX) 1031 return -EINVAL; 1032 1033 if (type == RTAX_CC_ALGO) { 1034 char tmp[TCP_CA_NAME_MAX]; 1035 1036 nla_strlcpy(tmp, nla, sizeof(tmp)); 1037 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca); 1038 if (val == TCP_CA_UNSPEC) 1039 return -EINVAL; 1040 } else { 1041 val = nla_get_u32(nla); 1042 } 1043 if (type == RTAX_ADVMSS && val > 65535 - 40) 1044 val = 65535 - 40; 1045 if (type == RTAX_MTU && val > 65535 - 15) 1046 val = 65535 - 15; 1047 if (type == RTAX_HOPLIMIT && val > 255) 1048 val = 255; 1049 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 1050 return -EINVAL; 1051 fi->fib_metrics->metrics[type - 1] = val; 1052 } 1053 1054 if (ecn_ca) 1055 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 1056 1057 return 0; 1058 } 1059 1060 struct fib_info *fib_create_info(struct fib_config *cfg, 1061 struct netlink_ext_ack *extack) 1062 { 1063 int err; 1064 struct fib_info *fi = NULL; 1065 struct fib_info *ofi; 1066 int nhs = 1; 1067 struct net *net = cfg->fc_nlinfo.nl_net; 1068 1069 if (cfg->fc_type > RTN_MAX) 1070 goto err_inval; 1071 1072 /* Fast check to catch the most weird cases */ 1073 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1074 NL_SET_ERR_MSG(extack, "Invalid scope"); 1075 goto err_inval; 1076 } 1077 1078 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1079 NL_SET_ERR_MSG(extack, 1080 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1081 goto err_inval; 1082 } 1083 1084 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1085 if (cfg->fc_mp) { 1086 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1087 if (nhs == 0) 1088 goto err_inval; 1089 } 1090 #endif 1091 1092 err = -ENOBUFS; 1093 if (fib_info_cnt >= fib_info_hash_size) { 1094 unsigned int new_size = fib_info_hash_size << 1; 1095 struct hlist_head *new_info_hash; 1096 struct hlist_head *new_laddrhash; 1097 unsigned int bytes; 1098 1099 if (!new_size) 1100 new_size = 16; 1101 bytes = new_size * sizeof(struct hlist_head *); 1102 new_info_hash = fib_info_hash_alloc(bytes); 1103 new_laddrhash = fib_info_hash_alloc(bytes); 1104 if (!new_info_hash || !new_laddrhash) { 1105 fib_info_hash_free(new_info_hash, bytes); 1106 fib_info_hash_free(new_laddrhash, bytes); 1107 } else 1108 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1109 1110 if (!fib_info_hash_size) 1111 goto failure; 1112 } 1113 1114 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1115 if (!fi) 1116 goto failure; 1117 if (cfg->fc_mx) { 1118 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL); 1119 if (unlikely(!fi->fib_metrics)) { 1120 kfree(fi); 1121 return ERR_PTR(err); 1122 } 1123 refcount_set(&fi->fib_metrics->refcnt, 1); 1124 } else { 1125 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics; 1126 } 1127 fib_info_cnt++; 1128 fi->fib_net = net; 1129 fi->fib_protocol = cfg->fc_protocol; 1130 fi->fib_scope = cfg->fc_scope; 1131 fi->fib_flags = cfg->fc_flags; 1132 fi->fib_priority = cfg->fc_priority; 1133 fi->fib_prefsrc = cfg->fc_prefsrc; 1134 fi->fib_type = cfg->fc_type; 1135 fi->fib_tb_id = cfg->fc_table; 1136 1137 fi->fib_nhs = nhs; 1138 change_nexthops(fi) { 1139 nexthop_nh->nh_parent = fi; 1140 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1141 if (!nexthop_nh->nh_pcpu_rth_output) 1142 goto failure; 1143 } endfor_nexthops(fi) 1144 1145 err = fib_convert_metrics(fi, cfg); 1146 if (err) 1147 goto failure; 1148 1149 if (cfg->fc_mp) { 1150 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1151 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); 1152 if (err != 0) 1153 goto failure; 1154 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) { 1155 NL_SET_ERR_MSG(extack, 1156 "Nexthop device index does not match RTA_OIF"); 1157 goto err_inval; 1158 } 1159 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) { 1160 NL_SET_ERR_MSG(extack, 1161 "Nexthop gateway does not match RTA_GATEWAY"); 1162 goto err_inval; 1163 } 1164 #ifdef CONFIG_IP_ROUTE_CLASSID 1165 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) { 1166 NL_SET_ERR_MSG(extack, 1167 "Nexthop class id does not match RTA_FLOW"); 1168 goto err_inval; 1169 } 1170 #endif 1171 #else 1172 NL_SET_ERR_MSG(extack, 1173 "Multipath support not enabled in kernel"); 1174 goto err_inval; 1175 #endif 1176 } else { 1177 struct fib_nh *nh = fi->fib_nh; 1178 1179 if (cfg->fc_encap) { 1180 struct lwtunnel_state *lwtstate; 1181 1182 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) { 1183 NL_SET_ERR_MSG(extack, 1184 "LWT encap type not specified"); 1185 goto err_inval; 1186 } 1187 err = lwtunnel_build_state(cfg->fc_encap_type, 1188 cfg->fc_encap, AF_INET, cfg, 1189 &lwtstate, extack); 1190 if (err) 1191 goto failure; 1192 1193 nh->nh_lwtstate = lwtstate_get(lwtstate); 1194 } 1195 nh->nh_oif = cfg->fc_oif; 1196 nh->nh_gw = cfg->fc_gw; 1197 nh->nh_flags = cfg->fc_flags; 1198 #ifdef CONFIG_IP_ROUTE_CLASSID 1199 nh->nh_tclassid = cfg->fc_flow; 1200 if (nh->nh_tclassid) 1201 fi->fib_net->ipv4.fib_num_tclassid_users++; 1202 #endif 1203 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1204 nh->nh_weight = 1; 1205 #endif 1206 } 1207 1208 if (fib_props[cfg->fc_type].error) { 1209 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) { 1210 NL_SET_ERR_MSG(extack, 1211 "Gateway, device and multipath can not be specified for this route type"); 1212 goto err_inval; 1213 } 1214 goto link_it; 1215 } else { 1216 switch (cfg->fc_type) { 1217 case RTN_UNICAST: 1218 case RTN_LOCAL: 1219 case RTN_BROADCAST: 1220 case RTN_ANYCAST: 1221 case RTN_MULTICAST: 1222 break; 1223 default: 1224 NL_SET_ERR_MSG(extack, "Invalid route type"); 1225 goto err_inval; 1226 } 1227 } 1228 1229 if (cfg->fc_scope > RT_SCOPE_HOST) { 1230 NL_SET_ERR_MSG(extack, "Invalid scope"); 1231 goto err_inval; 1232 } 1233 1234 if (cfg->fc_scope == RT_SCOPE_HOST) { 1235 struct fib_nh *nh = fi->fib_nh; 1236 1237 /* Local address is added. */ 1238 if (nhs != 1) { 1239 NL_SET_ERR_MSG(extack, 1240 "Route with host scope can not have multiple nexthops"); 1241 goto err_inval; 1242 } 1243 if (nh->nh_gw) { 1244 NL_SET_ERR_MSG(extack, 1245 "Route with host scope can not have a gateway"); 1246 goto err_inval; 1247 } 1248 nh->nh_scope = RT_SCOPE_NOWHERE; 1249 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1250 err = -ENODEV; 1251 if (!nh->nh_dev) 1252 goto failure; 1253 } else { 1254 int linkdown = 0; 1255 1256 change_nexthops(fi) { 1257 err = fib_check_nh(cfg, nexthop_nh, extack); 1258 if (err != 0) 1259 goto failure; 1260 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1261 linkdown++; 1262 } endfor_nexthops(fi) 1263 if (linkdown == fi->fib_nhs) 1264 fi->fib_flags |= RTNH_F_LINKDOWN; 1265 } 1266 1267 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1268 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1269 goto err_inval; 1270 } 1271 1272 change_nexthops(fi) { 1273 fib_info_update_nh_saddr(net, nexthop_nh); 1274 } endfor_nexthops(fi) 1275 1276 fib_rebalance(fi); 1277 1278 link_it: 1279 ofi = fib_find_info(fi); 1280 if (ofi) { 1281 fi->fib_dead = 1; 1282 free_fib_info(fi); 1283 ofi->fib_treeref++; 1284 return ofi; 1285 } 1286 1287 fi->fib_treeref++; 1288 refcount_set(&fi->fib_clntref, 1); 1289 spin_lock_bh(&fib_info_lock); 1290 hlist_add_head(&fi->fib_hash, 1291 &fib_info_hash[fib_info_hashfn(fi)]); 1292 if (fi->fib_prefsrc) { 1293 struct hlist_head *head; 1294 1295 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1296 hlist_add_head(&fi->fib_lhash, head); 1297 } 1298 change_nexthops(fi) { 1299 struct hlist_head *head; 1300 unsigned int hash; 1301 1302 if (!nexthop_nh->nh_dev) 1303 continue; 1304 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1305 head = &fib_info_devhash[hash]; 1306 hlist_add_head(&nexthop_nh->nh_hash, head); 1307 } endfor_nexthops(fi) 1308 spin_unlock_bh(&fib_info_lock); 1309 return fi; 1310 1311 err_inval: 1312 err = -EINVAL; 1313 1314 failure: 1315 if (fi) { 1316 fi->fib_dead = 1; 1317 free_fib_info(fi); 1318 } 1319 1320 return ERR_PTR(err); 1321 } 1322 1323 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1324 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1325 struct fib_info *fi, unsigned int flags) 1326 { 1327 struct nlmsghdr *nlh; 1328 struct rtmsg *rtm; 1329 1330 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1331 if (!nlh) 1332 return -EMSGSIZE; 1333 1334 rtm = nlmsg_data(nlh); 1335 rtm->rtm_family = AF_INET; 1336 rtm->rtm_dst_len = dst_len; 1337 rtm->rtm_src_len = 0; 1338 rtm->rtm_tos = tos; 1339 if (tb_id < 256) 1340 rtm->rtm_table = tb_id; 1341 else 1342 rtm->rtm_table = RT_TABLE_COMPAT; 1343 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1344 goto nla_put_failure; 1345 rtm->rtm_type = type; 1346 rtm->rtm_flags = fi->fib_flags; 1347 rtm->rtm_scope = fi->fib_scope; 1348 rtm->rtm_protocol = fi->fib_protocol; 1349 1350 if (rtm->rtm_dst_len && 1351 nla_put_in_addr(skb, RTA_DST, dst)) 1352 goto nla_put_failure; 1353 if (fi->fib_priority && 1354 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1355 goto nla_put_failure; 1356 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1357 goto nla_put_failure; 1358 1359 if (fi->fib_prefsrc && 1360 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1361 goto nla_put_failure; 1362 if (fi->fib_nhs == 1) { 1363 if (fi->fib_nh->nh_gw && 1364 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1365 goto nla_put_failure; 1366 if (fi->fib_nh->nh_oif && 1367 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1368 goto nla_put_failure; 1369 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1370 struct in_device *in_dev; 1371 1372 rcu_read_lock(); 1373 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev); 1374 if (in_dev && 1375 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1376 rtm->rtm_flags |= RTNH_F_DEAD; 1377 rcu_read_unlock(); 1378 } 1379 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD) 1380 rtm->rtm_flags |= RTNH_F_OFFLOAD; 1381 #ifdef CONFIG_IP_ROUTE_CLASSID 1382 if (fi->fib_nh[0].nh_tclassid && 1383 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1384 goto nla_put_failure; 1385 #endif 1386 if (fi->fib_nh->nh_lwtstate && 1387 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0) 1388 goto nla_put_failure; 1389 } 1390 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1391 if (fi->fib_nhs > 1) { 1392 struct rtnexthop *rtnh; 1393 struct nlattr *mp; 1394 1395 mp = nla_nest_start(skb, RTA_MULTIPATH); 1396 if (!mp) 1397 goto nla_put_failure; 1398 1399 for_nexthops(fi) { 1400 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1401 if (!rtnh) 1402 goto nla_put_failure; 1403 1404 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1405 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1406 struct in_device *in_dev; 1407 1408 rcu_read_lock(); 1409 in_dev = __in_dev_get_rcu(nh->nh_dev); 1410 if (in_dev && 1411 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1412 rtnh->rtnh_flags |= RTNH_F_DEAD; 1413 rcu_read_unlock(); 1414 } 1415 rtnh->rtnh_hops = nh->nh_weight - 1; 1416 rtnh->rtnh_ifindex = nh->nh_oif; 1417 1418 if (nh->nh_gw && 1419 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1420 goto nla_put_failure; 1421 #ifdef CONFIG_IP_ROUTE_CLASSID 1422 if (nh->nh_tclassid && 1423 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1424 goto nla_put_failure; 1425 #endif 1426 if (nh->nh_lwtstate && 1427 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0) 1428 goto nla_put_failure; 1429 1430 /* length of rtnetlink header + attributes */ 1431 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1432 } endfor_nexthops(fi); 1433 1434 nla_nest_end(skb, mp); 1435 } 1436 #endif 1437 nlmsg_end(skb, nlh); 1438 return 0; 1439 1440 nla_put_failure: 1441 nlmsg_cancel(skb, nlh); 1442 return -EMSGSIZE; 1443 } 1444 1445 /* 1446 * Update FIB if: 1447 * - local address disappeared -> we must delete all the entries 1448 * referring to it. 1449 * - device went down -> we must shutdown all nexthops going via it. 1450 */ 1451 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1452 { 1453 int ret = 0; 1454 unsigned int hash = fib_laddr_hashfn(local); 1455 struct hlist_head *head = &fib_info_laddrhash[hash]; 1456 struct net *net = dev_net(dev); 1457 int tb_id = l3mdev_fib_table(dev); 1458 struct fib_info *fi; 1459 1460 if (!fib_info_laddrhash || local == 0) 1461 return 0; 1462 1463 hlist_for_each_entry(fi, head, fib_lhash) { 1464 if (!net_eq(fi->fib_net, net) || 1465 fi->fib_tb_id != tb_id) 1466 continue; 1467 if (fi->fib_prefsrc == local) { 1468 fi->fib_flags |= RTNH_F_DEAD; 1469 ret++; 1470 } 1471 } 1472 return ret; 1473 } 1474 1475 static int call_fib_nh_notifiers(struct fib_nh *fib_nh, 1476 enum fib_event_type event_type) 1477 { 1478 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev); 1479 struct fib_nh_notifier_info info = { 1480 .fib_nh = fib_nh, 1481 }; 1482 1483 switch (event_type) { 1484 case FIB_EVENT_NH_ADD: 1485 if (fib_nh->nh_flags & RTNH_F_DEAD) 1486 break; 1487 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1488 fib_nh->nh_flags & RTNH_F_LINKDOWN) 1489 break; 1490 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type, 1491 &info.info); 1492 case FIB_EVENT_NH_DEL: 1493 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1494 fib_nh->nh_flags & RTNH_F_LINKDOWN) || 1495 (fib_nh->nh_flags & RTNH_F_DEAD)) 1496 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), 1497 event_type, &info.info); 1498 default: 1499 break; 1500 } 1501 1502 return NOTIFY_DONE; 1503 } 1504 1505 /* Event force Flags Description 1506 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1507 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1508 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1509 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1510 */ 1511 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1512 { 1513 int ret = 0; 1514 int scope = RT_SCOPE_NOWHERE; 1515 struct fib_info *prev_fi = NULL; 1516 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1517 struct hlist_head *head = &fib_info_devhash[hash]; 1518 struct fib_nh *nh; 1519 1520 if (force) 1521 scope = -1; 1522 1523 hlist_for_each_entry(nh, head, nh_hash) { 1524 struct fib_info *fi = nh->nh_parent; 1525 int dead; 1526 1527 BUG_ON(!fi->fib_nhs); 1528 if (nh->nh_dev != dev || fi == prev_fi) 1529 continue; 1530 prev_fi = fi; 1531 dead = 0; 1532 change_nexthops(fi) { 1533 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1534 dead++; 1535 else if (nexthop_nh->nh_dev == dev && 1536 nexthop_nh->nh_scope != scope) { 1537 switch (event) { 1538 case NETDEV_DOWN: 1539 case NETDEV_UNREGISTER: 1540 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1541 /* fall through */ 1542 case NETDEV_CHANGE: 1543 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1544 break; 1545 } 1546 call_fib_nh_notifiers(nexthop_nh, 1547 FIB_EVENT_NH_DEL); 1548 dead++; 1549 } 1550 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1551 if (event == NETDEV_UNREGISTER && 1552 nexthop_nh->nh_dev == dev) { 1553 dead = fi->fib_nhs; 1554 break; 1555 } 1556 #endif 1557 } endfor_nexthops(fi) 1558 if (dead == fi->fib_nhs) { 1559 switch (event) { 1560 case NETDEV_DOWN: 1561 case NETDEV_UNREGISTER: 1562 fi->fib_flags |= RTNH_F_DEAD; 1563 /* fall through */ 1564 case NETDEV_CHANGE: 1565 fi->fib_flags |= RTNH_F_LINKDOWN; 1566 break; 1567 } 1568 ret++; 1569 } 1570 1571 fib_rebalance(fi); 1572 } 1573 1574 return ret; 1575 } 1576 1577 /* Must be invoked inside of an RCU protected region. */ 1578 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1579 { 1580 struct fib_info *fi = NULL, *last_resort = NULL; 1581 struct hlist_head *fa_head = res->fa_head; 1582 struct fib_table *tb = res->table; 1583 u8 slen = 32 - res->prefixlen; 1584 int order = -1, last_idx = -1; 1585 struct fib_alias *fa, *fa1 = NULL; 1586 u32 last_prio = res->fi->fib_priority; 1587 u8 last_tos = 0; 1588 1589 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1590 struct fib_info *next_fi = fa->fa_info; 1591 1592 if (fa->fa_slen != slen) 1593 continue; 1594 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1595 continue; 1596 if (fa->tb_id != tb->tb_id) 1597 continue; 1598 if (next_fi->fib_priority > last_prio && 1599 fa->fa_tos == last_tos) { 1600 if (last_tos) 1601 continue; 1602 break; 1603 } 1604 if (next_fi->fib_flags & RTNH_F_DEAD) 1605 continue; 1606 last_tos = fa->fa_tos; 1607 last_prio = next_fi->fib_priority; 1608 1609 if (next_fi->fib_scope != res->scope || 1610 fa->fa_type != RTN_UNICAST) 1611 continue; 1612 if (!next_fi->fib_nh[0].nh_gw || 1613 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1614 continue; 1615 1616 fib_alias_accessed(fa); 1617 1618 if (!fi) { 1619 if (next_fi != res->fi) 1620 break; 1621 fa1 = fa; 1622 } else if (!fib_detect_death(fi, order, &last_resort, 1623 &last_idx, fa1->fa_default)) { 1624 fib_result_assign(res, fi); 1625 fa1->fa_default = order; 1626 goto out; 1627 } 1628 fi = next_fi; 1629 order++; 1630 } 1631 1632 if (order <= 0 || !fi) { 1633 if (fa1) 1634 fa1->fa_default = -1; 1635 goto out; 1636 } 1637 1638 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1639 fa1->fa_default)) { 1640 fib_result_assign(res, fi); 1641 fa1->fa_default = order; 1642 goto out; 1643 } 1644 1645 if (last_idx >= 0) 1646 fib_result_assign(res, last_resort); 1647 fa1->fa_default = last_idx; 1648 out: 1649 return; 1650 } 1651 1652 /* 1653 * Dead device goes up. We wake up dead nexthops. 1654 * It takes sense only on multipath routes. 1655 */ 1656 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1657 { 1658 struct fib_info *prev_fi; 1659 unsigned int hash; 1660 struct hlist_head *head; 1661 struct fib_nh *nh; 1662 int ret; 1663 1664 if (!(dev->flags & IFF_UP)) 1665 return 0; 1666 1667 if (nh_flags & RTNH_F_DEAD) { 1668 unsigned int flags = dev_get_flags(dev); 1669 1670 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1671 nh_flags |= RTNH_F_LINKDOWN; 1672 } 1673 1674 prev_fi = NULL; 1675 hash = fib_devindex_hashfn(dev->ifindex); 1676 head = &fib_info_devhash[hash]; 1677 ret = 0; 1678 1679 hlist_for_each_entry(nh, head, nh_hash) { 1680 struct fib_info *fi = nh->nh_parent; 1681 int alive; 1682 1683 BUG_ON(!fi->fib_nhs); 1684 if (nh->nh_dev != dev || fi == prev_fi) 1685 continue; 1686 1687 prev_fi = fi; 1688 alive = 0; 1689 change_nexthops(fi) { 1690 if (!(nexthop_nh->nh_flags & nh_flags)) { 1691 alive++; 1692 continue; 1693 } 1694 if (!nexthop_nh->nh_dev || 1695 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1696 continue; 1697 if (nexthop_nh->nh_dev != dev || 1698 !__in_dev_get_rtnl(dev)) 1699 continue; 1700 alive++; 1701 nexthop_nh->nh_flags &= ~nh_flags; 1702 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 1703 } endfor_nexthops(fi) 1704 1705 if (alive > 0) { 1706 fi->fib_flags &= ~nh_flags; 1707 ret++; 1708 } 1709 1710 fib_rebalance(fi); 1711 } 1712 1713 return ret; 1714 } 1715 1716 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1717 static bool fib_good_nh(const struct fib_nh *nh) 1718 { 1719 int state = NUD_REACHABLE; 1720 1721 if (nh->nh_scope == RT_SCOPE_LINK) { 1722 struct neighbour *n; 1723 1724 rcu_read_lock_bh(); 1725 1726 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1727 (__force u32)nh->nh_gw); 1728 if (n) 1729 state = n->nud_state; 1730 1731 rcu_read_unlock_bh(); 1732 } 1733 1734 return !!(state & NUD_VALID); 1735 } 1736 1737 void fib_select_multipath(struct fib_result *res, int hash) 1738 { 1739 struct fib_info *fi = res->fi; 1740 struct net *net = fi->fib_net; 1741 bool first = false; 1742 1743 for_nexthops(fi) { 1744 if (hash > atomic_read(&nh->nh_upper_bound)) 1745 continue; 1746 1747 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1748 fib_good_nh(nh)) { 1749 res->nh_sel = nhsel; 1750 return; 1751 } 1752 if (!first) { 1753 res->nh_sel = nhsel; 1754 first = true; 1755 } 1756 } endfor_nexthops(fi); 1757 } 1758 #endif 1759 1760 void fib_select_path(struct net *net, struct fib_result *res, 1761 struct flowi4 *fl4, const struct sk_buff *skb) 1762 { 1763 bool oif_check; 1764 1765 oif_check = (fl4->flowi4_oif == 0 || 1766 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF); 1767 1768 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1769 if (res->fi->fib_nhs > 1 && oif_check) { 1770 int h = fib_multipath_hash(res->fi, fl4, skb); 1771 1772 fib_select_multipath(res, h); 1773 } 1774 else 1775 #endif 1776 if (!res->prefixlen && 1777 res->table->tb_num_default > 1 && 1778 res->type == RTN_UNICAST && oif_check) 1779 fib_select_default(fl4, res); 1780 1781 if (!fl4->saddr) 1782 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1783 } 1784 EXPORT_SYMBOL_GPL(fib_select_path); 1785