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