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 } 604 605 static inline void fib_add_weight(struct fib_info *fi, 606 const struct fib_nh *nh) 607 { 608 fi->fib_weight += nh->nh_weight; 609 } 610 611 #else /* CONFIG_IP_ROUTE_MULTIPATH */ 612 613 #define fib_rebalance(fi) do { } while (0) 614 #define fib_add_weight(fi, nh) do { } while (0) 615 616 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 617 618 static int fib_encap_match(u16 encap_type, 619 struct nlattr *encap, 620 const struct fib_nh *nh, 621 const struct fib_config *cfg, 622 struct netlink_ext_ack *extack) 623 { 624 struct lwtunnel_state *lwtstate; 625 int ret, result = 0; 626 627 if (encap_type == LWTUNNEL_ENCAP_NONE) 628 return 0; 629 630 ret = lwtunnel_build_state(encap_type, encap, AF_INET, 631 cfg, &lwtstate, extack); 632 if (!ret) { 633 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate); 634 lwtstate_free(lwtstate); 635 } 636 637 return result; 638 } 639 640 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi, 641 struct netlink_ext_ack *extack) 642 { 643 #ifdef CONFIG_IP_ROUTE_MULTIPATH 644 struct rtnexthop *rtnh; 645 int remaining; 646 #endif 647 648 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 649 return 1; 650 651 if (cfg->fc_oif || cfg->fc_gw) { 652 if (cfg->fc_encap) { 653 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap, 654 fi->fib_nh, cfg, extack)) 655 return 1; 656 } 657 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 658 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 659 return 0; 660 return 1; 661 } 662 663 #ifdef CONFIG_IP_ROUTE_MULTIPATH 664 if (!cfg->fc_mp) 665 return 0; 666 667 rtnh = cfg->fc_mp; 668 remaining = cfg->fc_mp_len; 669 670 for_nexthops(fi) { 671 int attrlen; 672 673 if (!rtnh_ok(rtnh, remaining)) 674 return -EINVAL; 675 676 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 677 return 1; 678 679 attrlen = rtnh_attrlen(rtnh); 680 if (attrlen > 0) { 681 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 682 683 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 684 if (nla && nla_get_in_addr(nla) != nh->nh_gw) 685 return 1; 686 #ifdef CONFIG_IP_ROUTE_CLASSID 687 nla = nla_find(attrs, attrlen, RTA_FLOW); 688 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 689 return 1; 690 #endif 691 } 692 693 rtnh = rtnh_next(rtnh, &remaining); 694 } endfor_nexthops(fi); 695 #endif 696 return 0; 697 } 698 699 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) 700 { 701 struct nlattr *nla; 702 int remaining; 703 704 if (!cfg->fc_mx) 705 return true; 706 707 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 708 int type = nla_type(nla); 709 u32 val; 710 711 if (!type) 712 continue; 713 if (type > RTAX_MAX) 714 return false; 715 716 if (type == RTAX_CC_ALGO) { 717 char tmp[TCP_CA_NAME_MAX]; 718 bool ecn_ca = false; 719 720 nla_strlcpy(tmp, nla, sizeof(tmp)); 721 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 722 } else { 723 val = nla_get_u32(nla); 724 } 725 726 if (fi->fib_metrics->metrics[type - 1] != val) 727 return false; 728 } 729 730 return true; 731 } 732 733 734 /* 735 * Picture 736 * ------- 737 * 738 * Semantics of nexthop is very messy by historical reasons. 739 * We have to take into account, that: 740 * a) gateway can be actually local interface address, 741 * so that gatewayed route is direct. 742 * b) gateway must be on-link address, possibly 743 * described not by an ifaddr, but also by a direct route. 744 * c) If both gateway and interface are specified, they should not 745 * contradict. 746 * d) If we use tunnel routes, gateway could be not on-link. 747 * 748 * Attempt to reconcile all of these (alas, self-contradictory) conditions 749 * results in pretty ugly and hairy code with obscure logic. 750 * 751 * I chose to generalized it instead, so that the size 752 * of code does not increase practically, but it becomes 753 * much more general. 754 * Every prefix is assigned a "scope" value: "host" is local address, 755 * "link" is direct route, 756 * [ ... "site" ... "interior" ... ] 757 * and "universe" is true gateway route with global meaning. 758 * 759 * Every prefix refers to a set of "nexthop"s (gw, oif), 760 * where gw must have narrower scope. This recursion stops 761 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 762 * which means that gw is forced to be on link. 763 * 764 * Code is still hairy, but now it is apparently logically 765 * consistent and very flexible. F.e. as by-product it allows 766 * to co-exists in peace independent exterior and interior 767 * routing processes. 768 * 769 * Normally it looks as following. 770 * 771 * {universe prefix} -> (gw, oif) [scope link] 772 * | 773 * |-> {link prefix} -> (gw, oif) [scope local] 774 * | 775 * |-> {local prefix} (terminal node) 776 */ 777 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 778 struct fib_nh *nh, struct netlink_ext_ack *extack) 779 { 780 int err = 0; 781 struct net *net; 782 struct net_device *dev; 783 784 net = cfg->fc_nlinfo.nl_net; 785 if (nh->nh_gw) { 786 struct fib_result res; 787 788 if (nh->nh_flags & RTNH_F_ONLINK) { 789 unsigned int addr_type; 790 791 if (cfg->fc_scope >= RT_SCOPE_LINK) { 792 NL_SET_ERR_MSG(extack, 793 "Nexthop has invalid scope"); 794 return -EINVAL; 795 } 796 dev = __dev_get_by_index(net, nh->nh_oif); 797 if (!dev) 798 return -ENODEV; 799 if (!(dev->flags & IFF_UP)) { 800 NL_SET_ERR_MSG(extack, 801 "Nexthop device is not up"); 802 return -ENETDOWN; 803 } 804 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw); 805 if (addr_type != RTN_UNICAST) { 806 NL_SET_ERR_MSG(extack, 807 "Nexthop has invalid gateway"); 808 return -EINVAL; 809 } 810 if (!netif_carrier_ok(dev)) 811 nh->nh_flags |= RTNH_F_LINKDOWN; 812 nh->nh_dev = dev; 813 dev_hold(dev); 814 nh->nh_scope = RT_SCOPE_LINK; 815 return 0; 816 } 817 rcu_read_lock(); 818 { 819 struct fib_table *tbl = NULL; 820 struct flowi4 fl4 = { 821 .daddr = nh->nh_gw, 822 .flowi4_scope = cfg->fc_scope + 1, 823 .flowi4_oif = nh->nh_oif, 824 .flowi4_iif = LOOPBACK_IFINDEX, 825 }; 826 827 /* It is not necessary, but requires a bit of thinking */ 828 if (fl4.flowi4_scope < RT_SCOPE_LINK) 829 fl4.flowi4_scope = RT_SCOPE_LINK; 830 831 if (cfg->fc_table) 832 tbl = fib_get_table(net, cfg->fc_table); 833 834 if (tbl) 835 err = fib_table_lookup(tbl, &fl4, &res, 836 FIB_LOOKUP_IGNORE_LINKSTATE | 837 FIB_LOOKUP_NOREF); 838 839 /* on error or if no table given do full lookup. This 840 * is needed for example when nexthops are in the local 841 * table rather than the given table 842 */ 843 if (!tbl || err) { 844 err = fib_lookup(net, &fl4, &res, 845 FIB_LOOKUP_IGNORE_LINKSTATE); 846 } 847 848 if (err) { 849 NL_SET_ERR_MSG(extack, 850 "Nexthop has invalid gateway"); 851 rcu_read_unlock(); 852 return err; 853 } 854 } 855 err = -EINVAL; 856 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { 857 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); 858 goto out; 859 } 860 nh->nh_scope = res.scope; 861 nh->nh_oif = FIB_RES_OIF(res); 862 nh->nh_dev = dev = FIB_RES_DEV(res); 863 if (!dev) { 864 NL_SET_ERR_MSG(extack, 865 "No egress device for nexthop gateway"); 866 goto out; 867 } 868 dev_hold(dev); 869 if (!netif_carrier_ok(dev)) 870 nh->nh_flags |= RTNH_F_LINKDOWN; 871 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 872 } else { 873 struct in_device *in_dev; 874 875 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { 876 NL_SET_ERR_MSG(extack, 877 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); 878 return -EINVAL; 879 } 880 rcu_read_lock(); 881 err = -ENODEV; 882 in_dev = inetdev_by_index(net, nh->nh_oif); 883 if (!in_dev) 884 goto out; 885 err = -ENETDOWN; 886 if (!(in_dev->dev->flags & IFF_UP)) { 887 NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); 888 goto out; 889 } 890 nh->nh_dev = in_dev->dev; 891 dev_hold(nh->nh_dev); 892 nh->nh_scope = RT_SCOPE_HOST; 893 if (!netif_carrier_ok(nh->nh_dev)) 894 nh->nh_flags |= RTNH_F_LINKDOWN; 895 err = 0; 896 } 897 out: 898 rcu_read_unlock(); 899 return err; 900 } 901 902 static inline unsigned int fib_laddr_hashfn(__be32 val) 903 { 904 unsigned int mask = (fib_info_hash_size - 1); 905 906 return ((__force u32)val ^ 907 ((__force u32)val >> 7) ^ 908 ((__force u32)val >> 14)) & mask; 909 } 910 911 static struct hlist_head *fib_info_hash_alloc(int bytes) 912 { 913 if (bytes <= PAGE_SIZE) 914 return kzalloc(bytes, GFP_KERNEL); 915 else 916 return (struct hlist_head *) 917 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 918 get_order(bytes)); 919 } 920 921 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 922 { 923 if (!hash) 924 return; 925 926 if (bytes <= PAGE_SIZE) 927 kfree(hash); 928 else 929 free_pages((unsigned long) hash, get_order(bytes)); 930 } 931 932 static void fib_info_hash_move(struct hlist_head *new_info_hash, 933 struct hlist_head *new_laddrhash, 934 unsigned int new_size) 935 { 936 struct hlist_head *old_info_hash, *old_laddrhash; 937 unsigned int old_size = fib_info_hash_size; 938 unsigned int i, bytes; 939 940 spin_lock_bh(&fib_info_lock); 941 old_info_hash = fib_info_hash; 942 old_laddrhash = fib_info_laddrhash; 943 fib_info_hash_size = new_size; 944 945 for (i = 0; i < old_size; i++) { 946 struct hlist_head *head = &fib_info_hash[i]; 947 struct hlist_node *n; 948 struct fib_info *fi; 949 950 hlist_for_each_entry_safe(fi, n, head, fib_hash) { 951 struct hlist_head *dest; 952 unsigned int new_hash; 953 954 new_hash = fib_info_hashfn(fi); 955 dest = &new_info_hash[new_hash]; 956 hlist_add_head(&fi->fib_hash, dest); 957 } 958 } 959 fib_info_hash = new_info_hash; 960 961 for (i = 0; i < old_size; i++) { 962 struct hlist_head *lhead = &fib_info_laddrhash[i]; 963 struct hlist_node *n; 964 struct fib_info *fi; 965 966 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { 967 struct hlist_head *ldest; 968 unsigned int new_hash; 969 970 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 971 ldest = &new_laddrhash[new_hash]; 972 hlist_add_head(&fi->fib_lhash, ldest); 973 } 974 } 975 fib_info_laddrhash = new_laddrhash; 976 977 spin_unlock_bh(&fib_info_lock); 978 979 bytes = old_size * sizeof(struct hlist_head *); 980 fib_info_hash_free(old_info_hash, bytes); 981 fib_info_hash_free(old_laddrhash, bytes); 982 } 983 984 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 985 { 986 nh->nh_saddr = inet_select_addr(nh->nh_dev, 987 nh->nh_gw, 988 nh->nh_parent->fib_scope); 989 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 990 991 return nh->nh_saddr; 992 } 993 994 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) 995 { 996 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 997 fib_prefsrc != cfg->fc_dst) { 998 u32 tb_id = cfg->fc_table; 999 int rc; 1000 1001 if (tb_id == RT_TABLE_MAIN) 1002 tb_id = RT_TABLE_LOCAL; 1003 1004 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1005 fib_prefsrc, tb_id); 1006 1007 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { 1008 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, 1009 fib_prefsrc, RT_TABLE_LOCAL); 1010 } 1011 1012 if (rc != RTN_LOCAL) 1013 return false; 1014 } 1015 return true; 1016 } 1017 1018 static int 1019 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg) 1020 { 1021 bool ecn_ca = false; 1022 struct nlattr *nla; 1023 int remaining; 1024 1025 if (!cfg->fc_mx) 1026 return 0; 1027 1028 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 1029 int type = nla_type(nla); 1030 u32 val; 1031 1032 if (!type) 1033 continue; 1034 if (type > RTAX_MAX) 1035 return -EINVAL; 1036 1037 if (type == RTAX_CC_ALGO) { 1038 char tmp[TCP_CA_NAME_MAX]; 1039 1040 nla_strlcpy(tmp, nla, sizeof(tmp)); 1041 val = tcp_ca_get_key_by_name(tmp, &ecn_ca); 1042 if (val == TCP_CA_UNSPEC) 1043 return -EINVAL; 1044 } else { 1045 val = nla_get_u32(nla); 1046 } 1047 if (type == RTAX_ADVMSS && val > 65535 - 40) 1048 val = 65535 - 40; 1049 if (type == RTAX_MTU && val > 65535 - 15) 1050 val = 65535 - 15; 1051 if (type == RTAX_HOPLIMIT && val > 255) 1052 val = 255; 1053 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) 1054 return -EINVAL; 1055 fi->fib_metrics->metrics[type - 1] = val; 1056 } 1057 1058 if (ecn_ca) 1059 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA; 1060 1061 return 0; 1062 } 1063 1064 struct fib_info *fib_create_info(struct fib_config *cfg, 1065 struct netlink_ext_ack *extack) 1066 { 1067 int err; 1068 struct fib_info *fi = NULL; 1069 struct fib_info *ofi; 1070 int nhs = 1; 1071 struct net *net = cfg->fc_nlinfo.nl_net; 1072 1073 if (cfg->fc_type > RTN_MAX) 1074 goto err_inval; 1075 1076 /* Fast check to catch the most weird cases */ 1077 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { 1078 NL_SET_ERR_MSG(extack, "Invalid scope"); 1079 goto err_inval; 1080 } 1081 1082 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { 1083 NL_SET_ERR_MSG(extack, 1084 "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); 1085 goto err_inval; 1086 } 1087 1088 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1089 if (cfg->fc_mp) { 1090 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); 1091 if (nhs == 0) 1092 goto err_inval; 1093 } 1094 #endif 1095 1096 err = -ENOBUFS; 1097 if (fib_info_cnt >= fib_info_hash_size) { 1098 unsigned int new_size = fib_info_hash_size << 1; 1099 struct hlist_head *new_info_hash; 1100 struct hlist_head *new_laddrhash; 1101 unsigned int bytes; 1102 1103 if (!new_size) 1104 new_size = 16; 1105 bytes = new_size * sizeof(struct hlist_head *); 1106 new_info_hash = fib_info_hash_alloc(bytes); 1107 new_laddrhash = fib_info_hash_alloc(bytes); 1108 if (!new_info_hash || !new_laddrhash) { 1109 fib_info_hash_free(new_info_hash, bytes); 1110 fib_info_hash_free(new_laddrhash, bytes); 1111 } else 1112 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 1113 1114 if (!fib_info_hash_size) 1115 goto failure; 1116 } 1117 1118 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 1119 if (!fi) 1120 goto failure; 1121 if (cfg->fc_mx) { 1122 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL); 1123 if (unlikely(!fi->fib_metrics)) { 1124 kfree(fi); 1125 return ERR_PTR(err); 1126 } 1127 refcount_set(&fi->fib_metrics->refcnt, 1); 1128 } else { 1129 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics; 1130 } 1131 fib_info_cnt++; 1132 fi->fib_net = net; 1133 fi->fib_protocol = cfg->fc_protocol; 1134 fi->fib_scope = cfg->fc_scope; 1135 fi->fib_flags = cfg->fc_flags; 1136 fi->fib_priority = cfg->fc_priority; 1137 fi->fib_prefsrc = cfg->fc_prefsrc; 1138 fi->fib_type = cfg->fc_type; 1139 fi->fib_tb_id = cfg->fc_table; 1140 1141 fi->fib_nhs = nhs; 1142 change_nexthops(fi) { 1143 nexthop_nh->nh_parent = fi; 1144 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 1145 if (!nexthop_nh->nh_pcpu_rth_output) 1146 goto failure; 1147 } endfor_nexthops(fi) 1148 1149 err = fib_convert_metrics(fi, cfg); 1150 if (err) 1151 goto failure; 1152 1153 if (cfg->fc_mp) { 1154 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1155 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); 1156 if (err != 0) 1157 goto failure; 1158 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) { 1159 NL_SET_ERR_MSG(extack, 1160 "Nexthop device index does not match RTA_OIF"); 1161 goto err_inval; 1162 } 1163 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) { 1164 NL_SET_ERR_MSG(extack, 1165 "Nexthop gateway does not match RTA_GATEWAY"); 1166 goto err_inval; 1167 } 1168 #ifdef CONFIG_IP_ROUTE_CLASSID 1169 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) { 1170 NL_SET_ERR_MSG(extack, 1171 "Nexthop class id does not match RTA_FLOW"); 1172 goto err_inval; 1173 } 1174 #endif 1175 #else 1176 NL_SET_ERR_MSG(extack, 1177 "Multipath support not enabled in kernel"); 1178 goto err_inval; 1179 #endif 1180 } else { 1181 struct fib_nh *nh = fi->fib_nh; 1182 1183 if (cfg->fc_encap) { 1184 struct lwtunnel_state *lwtstate; 1185 1186 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) { 1187 NL_SET_ERR_MSG(extack, 1188 "LWT encap type not specified"); 1189 goto err_inval; 1190 } 1191 err = lwtunnel_build_state(cfg->fc_encap_type, 1192 cfg->fc_encap, AF_INET, cfg, 1193 &lwtstate, extack); 1194 if (err) 1195 goto failure; 1196 1197 nh->nh_lwtstate = lwtstate_get(lwtstate); 1198 } 1199 nh->nh_oif = cfg->fc_oif; 1200 nh->nh_gw = cfg->fc_gw; 1201 nh->nh_flags = cfg->fc_flags; 1202 #ifdef CONFIG_IP_ROUTE_CLASSID 1203 nh->nh_tclassid = cfg->fc_flow; 1204 if (nh->nh_tclassid) 1205 fi->fib_net->ipv4.fib_num_tclassid_users++; 1206 #endif 1207 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1208 nh->nh_weight = 1; 1209 #endif 1210 } 1211 1212 if (fib_props[cfg->fc_type].error) { 1213 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) { 1214 NL_SET_ERR_MSG(extack, 1215 "Gateway, device and multipath can not be specified for this route type"); 1216 goto err_inval; 1217 } 1218 goto link_it; 1219 } else { 1220 switch (cfg->fc_type) { 1221 case RTN_UNICAST: 1222 case RTN_LOCAL: 1223 case RTN_BROADCAST: 1224 case RTN_ANYCAST: 1225 case RTN_MULTICAST: 1226 break; 1227 default: 1228 NL_SET_ERR_MSG(extack, "Invalid route type"); 1229 goto err_inval; 1230 } 1231 } 1232 1233 if (cfg->fc_scope > RT_SCOPE_HOST) { 1234 NL_SET_ERR_MSG(extack, "Invalid scope"); 1235 goto err_inval; 1236 } 1237 1238 if (cfg->fc_scope == RT_SCOPE_HOST) { 1239 struct fib_nh *nh = fi->fib_nh; 1240 1241 /* Local address is added. */ 1242 if (nhs != 1) { 1243 NL_SET_ERR_MSG(extack, 1244 "Route with host scope can not have multiple nexthops"); 1245 goto err_inval; 1246 } 1247 if (nh->nh_gw) { 1248 NL_SET_ERR_MSG(extack, 1249 "Route with host scope can not have a gateway"); 1250 goto err_inval; 1251 } 1252 nh->nh_scope = RT_SCOPE_NOWHERE; 1253 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 1254 err = -ENODEV; 1255 if (!nh->nh_dev) 1256 goto failure; 1257 } else { 1258 int linkdown = 0; 1259 1260 change_nexthops(fi) { 1261 err = fib_check_nh(cfg, fi, nexthop_nh, extack); 1262 if (err != 0) 1263 goto failure; 1264 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN) 1265 linkdown++; 1266 } endfor_nexthops(fi) 1267 if (linkdown == fi->fib_nhs) 1268 fi->fib_flags |= RTNH_F_LINKDOWN; 1269 } 1270 1271 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { 1272 NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); 1273 goto err_inval; 1274 } 1275 1276 change_nexthops(fi) { 1277 fib_info_update_nh_saddr(net, nexthop_nh); 1278 fib_add_weight(fi, nexthop_nh); 1279 } endfor_nexthops(fi) 1280 1281 fib_rebalance(fi); 1282 1283 link_it: 1284 ofi = fib_find_info(fi); 1285 if (ofi) { 1286 fi->fib_dead = 1; 1287 free_fib_info(fi); 1288 ofi->fib_treeref++; 1289 return ofi; 1290 } 1291 1292 fi->fib_treeref++; 1293 refcount_set(&fi->fib_clntref, 1); 1294 spin_lock_bh(&fib_info_lock); 1295 hlist_add_head(&fi->fib_hash, 1296 &fib_info_hash[fib_info_hashfn(fi)]); 1297 if (fi->fib_prefsrc) { 1298 struct hlist_head *head; 1299 1300 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 1301 hlist_add_head(&fi->fib_lhash, head); 1302 } 1303 change_nexthops(fi) { 1304 struct hlist_head *head; 1305 unsigned int hash; 1306 1307 if (!nexthop_nh->nh_dev) 1308 continue; 1309 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 1310 head = &fib_info_devhash[hash]; 1311 hlist_add_head(&nexthop_nh->nh_hash, head); 1312 } endfor_nexthops(fi) 1313 spin_unlock_bh(&fib_info_lock); 1314 return fi; 1315 1316 err_inval: 1317 err = -EINVAL; 1318 1319 failure: 1320 if (fi) { 1321 fi->fib_dead = 1; 1322 free_fib_info(fi); 1323 } 1324 1325 return ERR_PTR(err); 1326 } 1327 1328 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 1329 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 1330 struct fib_info *fi, unsigned int flags) 1331 { 1332 struct nlmsghdr *nlh; 1333 struct rtmsg *rtm; 1334 1335 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1336 if (!nlh) 1337 return -EMSGSIZE; 1338 1339 rtm = nlmsg_data(nlh); 1340 rtm->rtm_family = AF_INET; 1341 rtm->rtm_dst_len = dst_len; 1342 rtm->rtm_src_len = 0; 1343 rtm->rtm_tos = tos; 1344 if (tb_id < 256) 1345 rtm->rtm_table = tb_id; 1346 else 1347 rtm->rtm_table = RT_TABLE_COMPAT; 1348 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1349 goto nla_put_failure; 1350 rtm->rtm_type = type; 1351 rtm->rtm_flags = fi->fib_flags; 1352 rtm->rtm_scope = fi->fib_scope; 1353 rtm->rtm_protocol = fi->fib_protocol; 1354 1355 if (rtm->rtm_dst_len && 1356 nla_put_in_addr(skb, RTA_DST, dst)) 1357 goto nla_put_failure; 1358 if (fi->fib_priority && 1359 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1360 goto nla_put_failure; 1361 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) 1362 goto nla_put_failure; 1363 1364 if (fi->fib_prefsrc && 1365 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1366 goto nla_put_failure; 1367 if (fi->fib_nhs == 1) { 1368 struct in_device *in_dev; 1369 1370 if (fi->fib_nh->nh_gw && 1371 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1372 goto nla_put_failure; 1373 if (fi->fib_nh->nh_oif && 1374 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1375 goto nla_put_failure; 1376 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) { 1377 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev); 1378 if (in_dev && 1379 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1380 rtm->rtm_flags |= RTNH_F_DEAD; 1381 } 1382 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD) 1383 rtm->rtm_flags |= RTNH_F_OFFLOAD; 1384 #ifdef CONFIG_IP_ROUTE_CLASSID 1385 if (fi->fib_nh[0].nh_tclassid && 1386 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1387 goto nla_put_failure; 1388 #endif 1389 if (fi->fib_nh->nh_lwtstate && 1390 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0) 1391 goto nla_put_failure; 1392 } 1393 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1394 if (fi->fib_nhs > 1) { 1395 struct rtnexthop *rtnh; 1396 struct nlattr *mp; 1397 1398 mp = nla_nest_start(skb, RTA_MULTIPATH); 1399 if (!mp) 1400 goto nla_put_failure; 1401 1402 for_nexthops(fi) { 1403 struct in_device *in_dev; 1404 1405 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1406 if (!rtnh) 1407 goto nla_put_failure; 1408 1409 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1410 if (nh->nh_flags & RTNH_F_LINKDOWN) { 1411 in_dev = __in_dev_get_rtnl(nh->nh_dev); 1412 if (in_dev && 1413 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev)) 1414 rtnh->rtnh_flags |= RTNH_F_DEAD; 1415 } 1416 rtnh->rtnh_hops = nh->nh_weight - 1; 1417 rtnh->rtnh_ifindex = nh->nh_oif; 1418 1419 if (nh->nh_gw && 1420 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw)) 1421 goto nla_put_failure; 1422 #ifdef CONFIG_IP_ROUTE_CLASSID 1423 if (nh->nh_tclassid && 1424 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1425 goto nla_put_failure; 1426 #endif 1427 if (nh->nh_lwtstate && 1428 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0) 1429 goto nla_put_failure; 1430 1431 /* length of rtnetlink header + attributes */ 1432 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1433 } endfor_nexthops(fi); 1434 1435 nla_nest_end(skb, mp); 1436 } 1437 #endif 1438 nlmsg_end(skb, nlh); 1439 return 0; 1440 1441 nla_put_failure: 1442 nlmsg_cancel(skb, nlh); 1443 return -EMSGSIZE; 1444 } 1445 1446 /* 1447 * Update FIB if: 1448 * - local address disappeared -> we must delete all the entries 1449 * referring to it. 1450 * - device went down -> we must shutdown all nexthops going via it. 1451 */ 1452 int fib_sync_down_addr(struct net_device *dev, __be32 local) 1453 { 1454 int ret = 0; 1455 unsigned int hash = fib_laddr_hashfn(local); 1456 struct hlist_head *head = &fib_info_laddrhash[hash]; 1457 struct net *net = dev_net(dev); 1458 int tb_id = l3mdev_fib_table(dev); 1459 struct fib_info *fi; 1460 1461 if (!fib_info_laddrhash || local == 0) 1462 return 0; 1463 1464 hlist_for_each_entry(fi, head, fib_lhash) { 1465 if (!net_eq(fi->fib_net, net) || 1466 fi->fib_tb_id != tb_id) 1467 continue; 1468 if (fi->fib_prefsrc == local) { 1469 fi->fib_flags |= RTNH_F_DEAD; 1470 ret++; 1471 } 1472 } 1473 return ret; 1474 } 1475 1476 static int call_fib_nh_notifiers(struct fib_nh *fib_nh, 1477 enum fib_event_type event_type) 1478 { 1479 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev); 1480 struct fib_nh_notifier_info info = { 1481 .fib_nh = fib_nh, 1482 }; 1483 1484 switch (event_type) { 1485 case FIB_EVENT_NH_ADD: 1486 if (fib_nh->nh_flags & RTNH_F_DEAD) 1487 break; 1488 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1489 fib_nh->nh_flags & RTNH_F_LINKDOWN) 1490 break; 1491 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type, 1492 &info.info); 1493 case FIB_EVENT_NH_DEL: 1494 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && 1495 fib_nh->nh_flags & RTNH_F_LINKDOWN) || 1496 (fib_nh->nh_flags & RTNH_F_DEAD)) 1497 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), 1498 event_type, &info.info); 1499 default: 1500 break; 1501 } 1502 1503 return NOTIFY_DONE; 1504 } 1505 1506 /* Event force Flags Description 1507 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host 1508 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host 1509 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed 1510 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed 1511 */ 1512 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 1513 { 1514 int ret = 0; 1515 int scope = RT_SCOPE_NOWHERE; 1516 struct fib_info *prev_fi = NULL; 1517 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1518 struct hlist_head *head = &fib_info_devhash[hash]; 1519 struct fib_nh *nh; 1520 1521 if (force) 1522 scope = -1; 1523 1524 hlist_for_each_entry(nh, head, nh_hash) { 1525 struct fib_info *fi = nh->nh_parent; 1526 int dead; 1527 1528 BUG_ON(!fi->fib_nhs); 1529 if (nh->nh_dev != dev || fi == prev_fi) 1530 continue; 1531 prev_fi = fi; 1532 dead = 0; 1533 change_nexthops(fi) { 1534 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1535 dead++; 1536 else if (nexthop_nh->nh_dev == dev && 1537 nexthop_nh->nh_scope != scope) { 1538 switch (event) { 1539 case NETDEV_DOWN: 1540 case NETDEV_UNREGISTER: 1541 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1542 /* fall through */ 1543 case NETDEV_CHANGE: 1544 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; 1545 break; 1546 } 1547 call_fib_nh_notifiers(nexthop_nh, 1548 FIB_EVENT_NH_DEL); 1549 dead++; 1550 } 1551 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1552 if (event == NETDEV_UNREGISTER && 1553 nexthop_nh->nh_dev == dev) { 1554 dead = fi->fib_nhs; 1555 break; 1556 } 1557 #endif 1558 } endfor_nexthops(fi) 1559 if (dead == fi->fib_nhs) { 1560 switch (event) { 1561 case NETDEV_DOWN: 1562 case NETDEV_UNREGISTER: 1563 fi->fib_flags |= RTNH_F_DEAD; 1564 /* fall through */ 1565 case NETDEV_CHANGE: 1566 fi->fib_flags |= RTNH_F_LINKDOWN; 1567 break; 1568 } 1569 ret++; 1570 } 1571 1572 fib_rebalance(fi); 1573 } 1574 1575 return ret; 1576 } 1577 1578 /* Must be invoked inside of an RCU protected region. */ 1579 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) 1580 { 1581 struct fib_info *fi = NULL, *last_resort = NULL; 1582 struct hlist_head *fa_head = res->fa_head; 1583 struct fib_table *tb = res->table; 1584 u8 slen = 32 - res->prefixlen; 1585 int order = -1, last_idx = -1; 1586 struct fib_alias *fa, *fa1 = NULL; 1587 u32 last_prio = res->fi->fib_priority; 1588 u8 last_tos = 0; 1589 1590 hlist_for_each_entry_rcu(fa, fa_head, fa_list) { 1591 struct fib_info *next_fi = fa->fa_info; 1592 1593 if (fa->fa_slen != slen) 1594 continue; 1595 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) 1596 continue; 1597 if (fa->tb_id != tb->tb_id) 1598 continue; 1599 if (next_fi->fib_priority > last_prio && 1600 fa->fa_tos == last_tos) { 1601 if (last_tos) 1602 continue; 1603 break; 1604 } 1605 if (next_fi->fib_flags & RTNH_F_DEAD) 1606 continue; 1607 last_tos = fa->fa_tos; 1608 last_prio = next_fi->fib_priority; 1609 1610 if (next_fi->fib_scope != res->scope || 1611 fa->fa_type != RTN_UNICAST) 1612 continue; 1613 if (!next_fi->fib_nh[0].nh_gw || 1614 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1615 continue; 1616 1617 fib_alias_accessed(fa); 1618 1619 if (!fi) { 1620 if (next_fi != res->fi) 1621 break; 1622 fa1 = fa; 1623 } else if (!fib_detect_death(fi, order, &last_resort, 1624 &last_idx, fa1->fa_default)) { 1625 fib_result_assign(res, fi); 1626 fa1->fa_default = order; 1627 goto out; 1628 } 1629 fi = next_fi; 1630 order++; 1631 } 1632 1633 if (order <= 0 || !fi) { 1634 if (fa1) 1635 fa1->fa_default = -1; 1636 goto out; 1637 } 1638 1639 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1640 fa1->fa_default)) { 1641 fib_result_assign(res, fi); 1642 fa1->fa_default = order; 1643 goto out; 1644 } 1645 1646 if (last_idx >= 0) 1647 fib_result_assign(res, last_resort); 1648 fa1->fa_default = last_idx; 1649 out: 1650 return; 1651 } 1652 1653 /* 1654 * Dead device goes up. We wake up dead nexthops. 1655 * It takes sense only on multipath routes. 1656 */ 1657 int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 1658 { 1659 struct fib_info *prev_fi; 1660 unsigned int hash; 1661 struct hlist_head *head; 1662 struct fib_nh *nh; 1663 int ret; 1664 1665 if (!(dev->flags & IFF_UP)) 1666 return 0; 1667 1668 if (nh_flags & RTNH_F_DEAD) { 1669 unsigned int flags = dev_get_flags(dev); 1670 1671 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1672 nh_flags |= RTNH_F_LINKDOWN; 1673 } 1674 1675 prev_fi = NULL; 1676 hash = fib_devindex_hashfn(dev->ifindex); 1677 head = &fib_info_devhash[hash]; 1678 ret = 0; 1679 1680 hlist_for_each_entry(nh, head, nh_hash) { 1681 struct fib_info *fi = nh->nh_parent; 1682 int alive; 1683 1684 BUG_ON(!fi->fib_nhs); 1685 if (nh->nh_dev != dev || fi == prev_fi) 1686 continue; 1687 1688 prev_fi = fi; 1689 alive = 0; 1690 change_nexthops(fi) { 1691 if (!(nexthop_nh->nh_flags & nh_flags)) { 1692 alive++; 1693 continue; 1694 } 1695 if (!nexthop_nh->nh_dev || 1696 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1697 continue; 1698 if (nexthop_nh->nh_dev != dev || 1699 !__in_dev_get_rtnl(dev)) 1700 continue; 1701 alive++; 1702 nexthop_nh->nh_flags &= ~nh_flags; 1703 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); 1704 } endfor_nexthops(fi) 1705 1706 if (alive > 0) { 1707 fi->fib_flags &= ~nh_flags; 1708 ret++; 1709 } 1710 1711 fib_rebalance(fi); 1712 } 1713 1714 return ret; 1715 } 1716 1717 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1718 static bool fib_good_nh(const struct fib_nh *nh) 1719 { 1720 int state = NUD_REACHABLE; 1721 1722 if (nh->nh_scope == RT_SCOPE_LINK) { 1723 struct neighbour *n; 1724 1725 rcu_read_lock_bh(); 1726 1727 n = __ipv4_neigh_lookup_noref(nh->nh_dev, 1728 (__force u32)nh->nh_gw); 1729 if (n) 1730 state = n->nud_state; 1731 1732 rcu_read_unlock_bh(); 1733 } 1734 1735 return !!(state & NUD_VALID); 1736 } 1737 1738 void fib_select_multipath(struct fib_result *res, int hash) 1739 { 1740 struct fib_info *fi = res->fi; 1741 struct net *net = fi->fib_net; 1742 bool first = false; 1743 1744 for_nexthops(fi) { 1745 if (hash > atomic_read(&nh->nh_upper_bound)) 1746 continue; 1747 1748 if (!net->ipv4.sysctl_fib_multipath_use_neigh || 1749 fib_good_nh(nh)) { 1750 res->nh_sel = nhsel; 1751 return; 1752 } 1753 if (!first) { 1754 res->nh_sel = nhsel; 1755 first = true; 1756 } 1757 } endfor_nexthops(fi); 1758 } 1759 #endif 1760 1761 void fib_select_path(struct net *net, struct fib_result *res, 1762 struct flowi4 *fl4, const struct sk_buff *skb) 1763 { 1764 bool oif_check; 1765 1766 oif_check = (fl4->flowi4_oif == 0 || 1767 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF); 1768 1769 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1770 if (res->fi->fib_nhs > 1 && oif_check) { 1771 int h = fib_multipath_hash(res->fi, fl4, skb); 1772 1773 fib_select_multipath(res, h); 1774 } 1775 else 1776 #endif 1777 if (!res->prefixlen && 1778 res->table->tb_num_default > 1 && 1779 res->type == RTN_UNICAST && oif_check) 1780 fib_select_default(fl4, res); 1781 1782 if (!fl4->saddr) 1783 fl4->saddr = FIB_RES_PREFSRC(net, *res); 1784 } 1785 EXPORT_SYMBOL_GPL(fib_select_path); 1786