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 <asm/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 36 #include <net/arp.h> 37 #include <net/ip.h> 38 #include <net/protocol.h> 39 #include <net/route.h> 40 #include <net/tcp.h> 41 #include <net/sock.h> 42 #include <net/ip_fib.h> 43 #include <net/netlink.h> 44 #include <net/nexthop.h> 45 46 #include "fib_lookup.h" 47 48 static DEFINE_SPINLOCK(fib_info_lock); 49 static struct hlist_head *fib_info_hash; 50 static struct hlist_head *fib_info_laddrhash; 51 static unsigned int fib_info_hash_size; 52 static unsigned int fib_info_cnt; 53 54 #define DEVINDEX_HASHBITS 8 55 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) 56 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; 57 58 #ifdef CONFIG_IP_ROUTE_MULTIPATH 59 60 static DEFINE_SPINLOCK(fib_multipath_lock); 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_free(&rt->dst); 156 } 157 158 static void free_nh_exceptions(struct fib_nh *nh) 159 { 160 struct fnhe_hash_bucket *hash = nh->nh_exceptions; 161 int i; 162 163 for (i = 0; i < FNHE_HASH_SIZE; i++) { 164 struct fib_nh_exception *fnhe; 165 166 fnhe = rcu_dereference_protected(hash[i].chain, 1); 167 while (fnhe) { 168 struct fib_nh_exception *next; 169 170 next = rcu_dereference_protected(fnhe->fnhe_next, 1); 171 172 rt_fibinfo_free(&fnhe->fnhe_rth); 173 174 kfree(fnhe); 175 176 fnhe = next; 177 } 178 } 179 kfree(hash); 180 } 181 182 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 183 { 184 int cpu; 185 186 if (!rtp) 187 return; 188 189 for_each_possible_cpu(cpu) { 190 struct rtable *rt; 191 192 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 193 if (rt) 194 dst_free(&rt->dst); 195 } 196 free_percpu(rtp); 197 } 198 199 /* Release a nexthop info record */ 200 static void free_fib_info_rcu(struct rcu_head *head) 201 { 202 struct fib_info *fi = container_of(head, struct fib_info, rcu); 203 204 change_nexthops(fi) { 205 if (nexthop_nh->nh_dev) 206 dev_put(nexthop_nh->nh_dev); 207 if (nexthop_nh->nh_exceptions) 208 free_nh_exceptions(nexthop_nh); 209 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 210 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 211 } endfor_nexthops(fi); 212 213 release_net(fi->fib_net); 214 if (fi->fib_metrics != (u32 *) dst_default_metrics) 215 kfree(fi->fib_metrics); 216 kfree(fi); 217 } 218 219 void free_fib_info(struct fib_info *fi) 220 { 221 if (fi->fib_dead == 0) { 222 pr_warn("Freeing alive fib_info %p\n", fi); 223 return; 224 } 225 fib_info_cnt--; 226 #ifdef CONFIG_IP_ROUTE_CLASSID 227 change_nexthops(fi) { 228 if (nexthop_nh->nh_tclassid) 229 fi->fib_net->ipv4.fib_num_tclassid_users--; 230 } endfor_nexthops(fi); 231 #endif 232 call_rcu(&fi->rcu, free_fib_info_rcu); 233 } 234 235 void fib_release_info(struct fib_info *fi) 236 { 237 spin_lock_bh(&fib_info_lock); 238 if (fi && --fi->fib_treeref == 0) { 239 hlist_del(&fi->fib_hash); 240 if (fi->fib_prefsrc) 241 hlist_del(&fi->fib_lhash); 242 change_nexthops(fi) { 243 if (!nexthop_nh->nh_dev) 244 continue; 245 hlist_del(&nexthop_nh->nh_hash); 246 } endfor_nexthops(fi) 247 fi->fib_dead = 1; 248 fib_info_put(fi); 249 } 250 spin_unlock_bh(&fib_info_lock); 251 } 252 253 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 254 { 255 const struct fib_nh *onh = ofi->fib_nh; 256 257 for_nexthops(fi) { 258 if (nh->nh_oif != onh->nh_oif || 259 nh->nh_gw != onh->nh_gw || 260 nh->nh_scope != onh->nh_scope || 261 #ifdef CONFIG_IP_ROUTE_MULTIPATH 262 nh->nh_weight != onh->nh_weight || 263 #endif 264 #ifdef CONFIG_IP_ROUTE_CLASSID 265 nh->nh_tclassid != onh->nh_tclassid || 266 #endif 267 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD)) 268 return -1; 269 onh++; 270 } endfor_nexthops(fi); 271 return 0; 272 } 273 274 static inline unsigned int fib_devindex_hashfn(unsigned int val) 275 { 276 unsigned int mask = DEVINDEX_HASHSIZE - 1; 277 278 return (val ^ 279 (val >> DEVINDEX_HASHBITS) ^ 280 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 281 } 282 283 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 284 { 285 unsigned int mask = (fib_info_hash_size - 1); 286 unsigned int val = fi->fib_nhs; 287 288 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 289 val ^= (__force u32)fi->fib_prefsrc; 290 val ^= fi->fib_priority; 291 for_nexthops(fi) { 292 val ^= fib_devindex_hashfn(nh->nh_oif); 293 } endfor_nexthops(fi) 294 295 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 296 } 297 298 static struct fib_info *fib_find_info(const struct fib_info *nfi) 299 { 300 struct hlist_head *head; 301 struct hlist_node *node; 302 struct fib_info *fi; 303 unsigned int hash; 304 305 hash = fib_info_hashfn(nfi); 306 head = &fib_info_hash[hash]; 307 308 hlist_for_each_entry(fi, node, head, fib_hash) { 309 if (!net_eq(fi->fib_net, nfi->fib_net)) 310 continue; 311 if (fi->fib_nhs != nfi->fib_nhs) 312 continue; 313 if (nfi->fib_protocol == fi->fib_protocol && 314 nfi->fib_scope == fi->fib_scope && 315 nfi->fib_prefsrc == fi->fib_prefsrc && 316 nfi->fib_priority == fi->fib_priority && 317 nfi->fib_type == fi->fib_type && 318 memcmp(nfi->fib_metrics, fi->fib_metrics, 319 sizeof(u32) * RTAX_MAX) == 0 && 320 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 && 321 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) 322 return fi; 323 } 324 325 return NULL; 326 } 327 328 /* Check, that the gateway is already configured. 329 * Used only by redirect accept routine. 330 */ 331 int ip_fib_check_default(__be32 gw, struct net_device *dev) 332 { 333 struct hlist_head *head; 334 struct hlist_node *node; 335 struct fib_nh *nh; 336 unsigned int hash; 337 338 spin_lock(&fib_info_lock); 339 340 hash = fib_devindex_hashfn(dev->ifindex); 341 head = &fib_info_devhash[hash]; 342 hlist_for_each_entry(nh, node, head, nh_hash) { 343 if (nh->nh_dev == dev && 344 nh->nh_gw == gw && 345 !(nh->nh_flags & RTNH_F_DEAD)) { 346 spin_unlock(&fib_info_lock); 347 return 0; 348 } 349 } 350 351 spin_unlock(&fib_info_lock); 352 353 return -1; 354 } 355 356 static inline size_t fib_nlmsg_size(struct fib_info *fi) 357 { 358 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) 359 + nla_total_size(4) /* RTA_TABLE */ 360 + nla_total_size(4) /* RTA_DST */ 361 + nla_total_size(4) /* RTA_PRIORITY */ 362 + nla_total_size(4); /* RTA_PREFSRC */ 363 364 /* space for nested metrics */ 365 payload += nla_total_size((RTAX_MAX * nla_total_size(4))); 366 367 if (fi->fib_nhs) { 368 /* Also handles the special case fib_nhs == 1 */ 369 370 /* each nexthop is packed in an attribute */ 371 size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); 372 373 /* may contain flow and gateway attribute */ 374 nhsize += 2 * nla_total_size(4); 375 376 /* all nexthops are packed in a nested attribute */ 377 payload += nla_total_size(fi->fib_nhs * nhsize); 378 } 379 380 return payload; 381 } 382 383 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, 384 int dst_len, u32 tb_id, struct nl_info *info, 385 unsigned int nlm_flags) 386 { 387 struct sk_buff *skb; 388 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 389 int err = -ENOBUFS; 390 391 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); 392 if (skb == NULL) 393 goto errout; 394 395 err = fib_dump_info(skb, info->portid, seq, event, tb_id, 396 fa->fa_type, key, dst_len, 397 fa->fa_tos, fa->fa_info, nlm_flags); 398 if (err < 0) { 399 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ 400 WARN_ON(err == -EMSGSIZE); 401 kfree_skb(skb); 402 goto errout; 403 } 404 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE, 405 info->nlh, GFP_KERNEL); 406 return; 407 errout: 408 if (err < 0) 409 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); 410 } 411 412 /* Return the first fib alias matching TOS with 413 * priority less than or equal to PRIO. 414 */ 415 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio) 416 { 417 if (fah) { 418 struct fib_alias *fa; 419 list_for_each_entry(fa, fah, fa_list) { 420 if (fa->fa_tos > tos) 421 continue; 422 if (fa->fa_info->fib_priority >= prio || 423 fa->fa_tos < tos) 424 return fa; 425 } 426 } 427 return NULL; 428 } 429 430 int fib_detect_death(struct fib_info *fi, int order, 431 struct fib_info **last_resort, int *last_idx, int dflt) 432 { 433 struct neighbour *n; 434 int state = NUD_NONE; 435 436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); 437 if (n) { 438 state = n->nud_state; 439 neigh_release(n); 440 } 441 if (state == NUD_REACHABLE) 442 return 0; 443 if ((state & NUD_VALID) && order != dflt) 444 return 0; 445 if ((state & NUD_VALID) || 446 (*last_idx < 0 && order > dflt)) { 447 *last_resort = fi; 448 *last_idx = order; 449 } 450 return 1; 451 } 452 453 #ifdef CONFIG_IP_ROUTE_MULTIPATH 454 455 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining) 456 { 457 int nhs = 0; 458 459 while (rtnh_ok(rtnh, remaining)) { 460 nhs++; 461 rtnh = rtnh_next(rtnh, &remaining); 462 } 463 464 /* leftover implies invalid nexthop configuration, discard it */ 465 return remaining > 0 ? 0 : nhs; 466 } 467 468 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, 469 int remaining, struct fib_config *cfg) 470 { 471 change_nexthops(fi) { 472 int attrlen; 473 474 if (!rtnh_ok(rtnh, remaining)) 475 return -EINVAL; 476 477 nexthop_nh->nh_flags = 478 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; 479 nexthop_nh->nh_oif = rtnh->rtnh_ifindex; 480 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; 481 482 attrlen = rtnh_attrlen(rtnh); 483 if (attrlen > 0) { 484 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 485 486 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 487 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0; 488 #ifdef CONFIG_IP_ROUTE_CLASSID 489 nla = nla_find(attrs, attrlen, RTA_FLOW); 490 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; 491 if (nexthop_nh->nh_tclassid) 492 fi->fib_net->ipv4.fib_num_tclassid_users++; 493 #endif 494 } 495 496 rtnh = rtnh_next(rtnh, &remaining); 497 } endfor_nexthops(fi); 498 499 return 0; 500 } 501 502 #endif 503 504 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) 505 { 506 #ifdef CONFIG_IP_ROUTE_MULTIPATH 507 struct rtnexthop *rtnh; 508 int remaining; 509 #endif 510 511 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) 512 return 1; 513 514 if (cfg->fc_oif || cfg->fc_gw) { 515 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && 516 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) 517 return 0; 518 return 1; 519 } 520 521 #ifdef CONFIG_IP_ROUTE_MULTIPATH 522 if (cfg->fc_mp == NULL) 523 return 0; 524 525 rtnh = cfg->fc_mp; 526 remaining = cfg->fc_mp_len; 527 528 for_nexthops(fi) { 529 int attrlen; 530 531 if (!rtnh_ok(rtnh, remaining)) 532 return -EINVAL; 533 534 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) 535 return 1; 536 537 attrlen = rtnh_attrlen(rtnh); 538 if (attrlen < 0) { 539 struct nlattr *nla, *attrs = rtnh_attrs(rtnh); 540 541 nla = nla_find(attrs, attrlen, RTA_GATEWAY); 542 if (nla && nla_get_be32(nla) != nh->nh_gw) 543 return 1; 544 #ifdef CONFIG_IP_ROUTE_CLASSID 545 nla = nla_find(attrs, attrlen, RTA_FLOW); 546 if (nla && nla_get_u32(nla) != nh->nh_tclassid) 547 return 1; 548 #endif 549 } 550 551 rtnh = rtnh_next(rtnh, &remaining); 552 } endfor_nexthops(fi); 553 #endif 554 return 0; 555 } 556 557 558 /* 559 * Picture 560 * ------- 561 * 562 * Semantics of nexthop is very messy by historical reasons. 563 * We have to take into account, that: 564 * a) gateway can be actually local interface address, 565 * so that gatewayed route is direct. 566 * b) gateway must be on-link address, possibly 567 * described not by an ifaddr, but also by a direct route. 568 * c) If both gateway and interface are specified, they should not 569 * contradict. 570 * d) If we use tunnel routes, gateway could be not on-link. 571 * 572 * Attempt to reconcile all of these (alas, self-contradictory) conditions 573 * results in pretty ugly and hairy code with obscure logic. 574 * 575 * I chose to generalized it instead, so that the size 576 * of code does not increase practically, but it becomes 577 * much more general. 578 * Every prefix is assigned a "scope" value: "host" is local address, 579 * "link" is direct route, 580 * [ ... "site" ... "interior" ... ] 581 * and "universe" is true gateway route with global meaning. 582 * 583 * Every prefix refers to a set of "nexthop"s (gw, oif), 584 * where gw must have narrower scope. This recursion stops 585 * when gw has LOCAL scope or if "nexthop" is declared ONLINK, 586 * which means that gw is forced to be on link. 587 * 588 * Code is still hairy, but now it is apparently logically 589 * consistent and very flexible. F.e. as by-product it allows 590 * to co-exists in peace independent exterior and interior 591 * routing processes. 592 * 593 * Normally it looks as following. 594 * 595 * {universe prefix} -> (gw, oif) [scope link] 596 * | 597 * |-> {link prefix} -> (gw, oif) [scope local] 598 * | 599 * |-> {local prefix} (terminal node) 600 */ 601 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, 602 struct fib_nh *nh) 603 { 604 int err; 605 struct net *net; 606 struct net_device *dev; 607 608 net = cfg->fc_nlinfo.nl_net; 609 if (nh->nh_gw) { 610 struct fib_result res; 611 612 if (nh->nh_flags & RTNH_F_ONLINK) { 613 614 if (cfg->fc_scope >= RT_SCOPE_LINK) 615 return -EINVAL; 616 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST) 617 return -EINVAL; 618 dev = __dev_get_by_index(net, nh->nh_oif); 619 if (!dev) 620 return -ENODEV; 621 if (!(dev->flags & IFF_UP)) 622 return -ENETDOWN; 623 nh->nh_dev = dev; 624 dev_hold(dev); 625 nh->nh_scope = RT_SCOPE_LINK; 626 return 0; 627 } 628 rcu_read_lock(); 629 { 630 struct flowi4 fl4 = { 631 .daddr = nh->nh_gw, 632 .flowi4_scope = cfg->fc_scope + 1, 633 .flowi4_oif = nh->nh_oif, 634 }; 635 636 /* It is not necessary, but requires a bit of thinking */ 637 if (fl4.flowi4_scope < RT_SCOPE_LINK) 638 fl4.flowi4_scope = RT_SCOPE_LINK; 639 err = fib_lookup(net, &fl4, &res); 640 if (err) { 641 rcu_read_unlock(); 642 return err; 643 } 644 } 645 err = -EINVAL; 646 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) 647 goto out; 648 nh->nh_scope = res.scope; 649 nh->nh_oif = FIB_RES_OIF(res); 650 nh->nh_dev = dev = FIB_RES_DEV(res); 651 if (!dev) 652 goto out; 653 dev_hold(dev); 654 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; 655 } else { 656 struct in_device *in_dev; 657 658 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) 659 return -EINVAL; 660 661 rcu_read_lock(); 662 err = -ENODEV; 663 in_dev = inetdev_by_index(net, nh->nh_oif); 664 if (in_dev == NULL) 665 goto out; 666 err = -ENETDOWN; 667 if (!(in_dev->dev->flags & IFF_UP)) 668 goto out; 669 nh->nh_dev = in_dev->dev; 670 dev_hold(nh->nh_dev); 671 nh->nh_scope = RT_SCOPE_HOST; 672 err = 0; 673 } 674 out: 675 rcu_read_unlock(); 676 return err; 677 } 678 679 static inline unsigned int fib_laddr_hashfn(__be32 val) 680 { 681 unsigned int mask = (fib_info_hash_size - 1); 682 683 return ((__force u32)val ^ 684 ((__force u32)val >> 7) ^ 685 ((__force u32)val >> 14)) & mask; 686 } 687 688 static struct hlist_head *fib_info_hash_alloc(int bytes) 689 { 690 if (bytes <= PAGE_SIZE) 691 return kzalloc(bytes, GFP_KERNEL); 692 else 693 return (struct hlist_head *) 694 __get_free_pages(GFP_KERNEL | __GFP_ZERO, 695 get_order(bytes)); 696 } 697 698 static void fib_info_hash_free(struct hlist_head *hash, int bytes) 699 { 700 if (!hash) 701 return; 702 703 if (bytes <= PAGE_SIZE) 704 kfree(hash); 705 else 706 free_pages((unsigned long) hash, get_order(bytes)); 707 } 708 709 static void fib_info_hash_move(struct hlist_head *new_info_hash, 710 struct hlist_head *new_laddrhash, 711 unsigned int new_size) 712 { 713 struct hlist_head *old_info_hash, *old_laddrhash; 714 unsigned int old_size = fib_info_hash_size; 715 unsigned int i, bytes; 716 717 spin_lock_bh(&fib_info_lock); 718 old_info_hash = fib_info_hash; 719 old_laddrhash = fib_info_laddrhash; 720 fib_info_hash_size = new_size; 721 722 for (i = 0; i < old_size; i++) { 723 struct hlist_head *head = &fib_info_hash[i]; 724 struct hlist_node *node, *n; 725 struct fib_info *fi; 726 727 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) { 728 struct hlist_head *dest; 729 unsigned int new_hash; 730 731 hlist_del(&fi->fib_hash); 732 733 new_hash = fib_info_hashfn(fi); 734 dest = &new_info_hash[new_hash]; 735 hlist_add_head(&fi->fib_hash, dest); 736 } 737 } 738 fib_info_hash = new_info_hash; 739 740 for (i = 0; i < old_size; i++) { 741 struct hlist_head *lhead = &fib_info_laddrhash[i]; 742 struct hlist_node *node, *n; 743 struct fib_info *fi; 744 745 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) { 746 struct hlist_head *ldest; 747 unsigned int new_hash; 748 749 hlist_del(&fi->fib_lhash); 750 751 new_hash = fib_laddr_hashfn(fi->fib_prefsrc); 752 ldest = &new_laddrhash[new_hash]; 753 hlist_add_head(&fi->fib_lhash, ldest); 754 } 755 } 756 fib_info_laddrhash = new_laddrhash; 757 758 spin_unlock_bh(&fib_info_lock); 759 760 bytes = old_size * sizeof(struct hlist_head *); 761 fib_info_hash_free(old_info_hash, bytes); 762 fib_info_hash_free(old_laddrhash, bytes); 763 } 764 765 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh) 766 { 767 nh->nh_saddr = inet_select_addr(nh->nh_dev, 768 nh->nh_gw, 769 nh->nh_parent->fib_scope); 770 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid); 771 772 return nh->nh_saddr; 773 } 774 775 struct fib_info *fib_create_info(struct fib_config *cfg) 776 { 777 int err; 778 struct fib_info *fi = NULL; 779 struct fib_info *ofi; 780 int nhs = 1; 781 struct net *net = cfg->fc_nlinfo.nl_net; 782 783 if (cfg->fc_type > RTN_MAX) 784 goto err_inval; 785 786 /* Fast check to catch the most weird cases */ 787 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) 788 goto err_inval; 789 790 #ifdef CONFIG_IP_ROUTE_MULTIPATH 791 if (cfg->fc_mp) { 792 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); 793 if (nhs == 0) 794 goto err_inval; 795 } 796 #endif 797 798 err = -ENOBUFS; 799 if (fib_info_cnt >= fib_info_hash_size) { 800 unsigned int new_size = fib_info_hash_size << 1; 801 struct hlist_head *new_info_hash; 802 struct hlist_head *new_laddrhash; 803 unsigned int bytes; 804 805 if (!new_size) 806 new_size = 16; 807 bytes = new_size * sizeof(struct hlist_head *); 808 new_info_hash = fib_info_hash_alloc(bytes); 809 new_laddrhash = fib_info_hash_alloc(bytes); 810 if (!new_info_hash || !new_laddrhash) { 811 fib_info_hash_free(new_info_hash, bytes); 812 fib_info_hash_free(new_laddrhash, bytes); 813 } else 814 fib_info_hash_move(new_info_hash, new_laddrhash, new_size); 815 816 if (!fib_info_hash_size) 817 goto failure; 818 } 819 820 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); 821 if (fi == NULL) 822 goto failure; 823 if (cfg->fc_mx) { 824 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); 825 if (!fi->fib_metrics) 826 goto failure; 827 } else 828 fi->fib_metrics = (u32 *) dst_default_metrics; 829 fib_info_cnt++; 830 831 fi->fib_net = hold_net(net); 832 fi->fib_protocol = cfg->fc_protocol; 833 fi->fib_scope = cfg->fc_scope; 834 fi->fib_flags = cfg->fc_flags; 835 fi->fib_priority = cfg->fc_priority; 836 fi->fib_prefsrc = cfg->fc_prefsrc; 837 fi->fib_type = cfg->fc_type; 838 839 fi->fib_nhs = nhs; 840 change_nexthops(fi) { 841 nexthop_nh->nh_parent = fi; 842 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *); 843 if (!nexthop_nh->nh_pcpu_rth_output) 844 goto failure; 845 } endfor_nexthops(fi) 846 847 if (cfg->fc_mx) { 848 struct nlattr *nla; 849 int remaining; 850 851 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { 852 int type = nla_type(nla); 853 854 if (type) { 855 u32 val; 856 857 if (type > RTAX_MAX) 858 goto err_inval; 859 val = nla_get_u32(nla); 860 if (type == RTAX_ADVMSS && val > 65535 - 40) 861 val = 65535 - 40; 862 if (type == RTAX_MTU && val > 65535 - 15) 863 val = 65535 - 15; 864 fi->fib_metrics[type - 1] = val; 865 } 866 } 867 } 868 869 if (cfg->fc_mp) { 870 #ifdef CONFIG_IP_ROUTE_MULTIPATH 871 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); 872 if (err != 0) 873 goto failure; 874 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) 875 goto err_inval; 876 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) 877 goto err_inval; 878 #ifdef CONFIG_IP_ROUTE_CLASSID 879 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) 880 goto err_inval; 881 #endif 882 #else 883 goto err_inval; 884 #endif 885 } else { 886 struct fib_nh *nh = fi->fib_nh; 887 888 nh->nh_oif = cfg->fc_oif; 889 nh->nh_gw = cfg->fc_gw; 890 nh->nh_flags = cfg->fc_flags; 891 #ifdef CONFIG_IP_ROUTE_CLASSID 892 nh->nh_tclassid = cfg->fc_flow; 893 if (nh->nh_tclassid) 894 fi->fib_net->ipv4.fib_num_tclassid_users++; 895 #endif 896 #ifdef CONFIG_IP_ROUTE_MULTIPATH 897 nh->nh_weight = 1; 898 #endif 899 } 900 901 if (fib_props[cfg->fc_type].error) { 902 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) 903 goto err_inval; 904 goto link_it; 905 } else { 906 switch (cfg->fc_type) { 907 case RTN_UNICAST: 908 case RTN_LOCAL: 909 case RTN_BROADCAST: 910 case RTN_ANYCAST: 911 case RTN_MULTICAST: 912 break; 913 default: 914 goto err_inval; 915 } 916 } 917 918 if (cfg->fc_scope > RT_SCOPE_HOST) 919 goto err_inval; 920 921 if (cfg->fc_scope == RT_SCOPE_HOST) { 922 struct fib_nh *nh = fi->fib_nh; 923 924 /* Local address is added. */ 925 if (nhs != 1 || nh->nh_gw) 926 goto err_inval; 927 nh->nh_scope = RT_SCOPE_NOWHERE; 928 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); 929 err = -ENODEV; 930 if (nh->nh_dev == NULL) 931 goto failure; 932 } else { 933 change_nexthops(fi) { 934 err = fib_check_nh(cfg, fi, nexthop_nh); 935 if (err != 0) 936 goto failure; 937 } endfor_nexthops(fi) 938 } 939 940 if (fi->fib_prefsrc) { 941 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || 942 fi->fib_prefsrc != cfg->fc_dst) 943 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL) 944 goto err_inval; 945 } 946 947 change_nexthops(fi) { 948 fib_info_update_nh_saddr(net, nexthop_nh); 949 } endfor_nexthops(fi) 950 951 link_it: 952 ofi = fib_find_info(fi); 953 if (ofi) { 954 fi->fib_dead = 1; 955 free_fib_info(fi); 956 ofi->fib_treeref++; 957 return ofi; 958 } 959 960 fi->fib_treeref++; 961 atomic_inc(&fi->fib_clntref); 962 spin_lock_bh(&fib_info_lock); 963 hlist_add_head(&fi->fib_hash, 964 &fib_info_hash[fib_info_hashfn(fi)]); 965 if (fi->fib_prefsrc) { 966 struct hlist_head *head; 967 968 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; 969 hlist_add_head(&fi->fib_lhash, head); 970 } 971 change_nexthops(fi) { 972 struct hlist_head *head; 973 unsigned int hash; 974 975 if (!nexthop_nh->nh_dev) 976 continue; 977 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); 978 head = &fib_info_devhash[hash]; 979 hlist_add_head(&nexthop_nh->nh_hash, head); 980 } endfor_nexthops(fi) 981 spin_unlock_bh(&fib_info_lock); 982 return fi; 983 984 err_inval: 985 err = -EINVAL; 986 987 failure: 988 if (fi) { 989 fi->fib_dead = 1; 990 free_fib_info(fi); 991 } 992 993 return ERR_PTR(err); 994 } 995 996 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 997 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos, 998 struct fib_info *fi, unsigned int flags) 999 { 1000 struct nlmsghdr *nlh; 1001 struct rtmsg *rtm; 1002 1003 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); 1004 if (nlh == NULL) 1005 return -EMSGSIZE; 1006 1007 rtm = nlmsg_data(nlh); 1008 rtm->rtm_family = AF_INET; 1009 rtm->rtm_dst_len = dst_len; 1010 rtm->rtm_src_len = 0; 1011 rtm->rtm_tos = tos; 1012 if (tb_id < 256) 1013 rtm->rtm_table = tb_id; 1014 else 1015 rtm->rtm_table = RT_TABLE_COMPAT; 1016 if (nla_put_u32(skb, RTA_TABLE, tb_id)) 1017 goto nla_put_failure; 1018 rtm->rtm_type = type; 1019 rtm->rtm_flags = fi->fib_flags; 1020 rtm->rtm_scope = fi->fib_scope; 1021 rtm->rtm_protocol = fi->fib_protocol; 1022 1023 if (rtm->rtm_dst_len && 1024 nla_put_be32(skb, RTA_DST, dst)) 1025 goto nla_put_failure; 1026 if (fi->fib_priority && 1027 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) 1028 goto nla_put_failure; 1029 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) 1030 goto nla_put_failure; 1031 1032 if (fi->fib_prefsrc && 1033 nla_put_be32(skb, RTA_PREFSRC, fi->fib_prefsrc)) 1034 goto nla_put_failure; 1035 if (fi->fib_nhs == 1) { 1036 if (fi->fib_nh->nh_gw && 1037 nla_put_be32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) 1038 goto nla_put_failure; 1039 if (fi->fib_nh->nh_oif && 1040 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) 1041 goto nla_put_failure; 1042 #ifdef CONFIG_IP_ROUTE_CLASSID 1043 if (fi->fib_nh[0].nh_tclassid && 1044 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) 1045 goto nla_put_failure; 1046 #endif 1047 } 1048 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1049 if (fi->fib_nhs > 1) { 1050 struct rtnexthop *rtnh; 1051 struct nlattr *mp; 1052 1053 mp = nla_nest_start(skb, RTA_MULTIPATH); 1054 if (mp == NULL) 1055 goto nla_put_failure; 1056 1057 for_nexthops(fi) { 1058 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); 1059 if (rtnh == NULL) 1060 goto nla_put_failure; 1061 1062 rtnh->rtnh_flags = nh->nh_flags & 0xFF; 1063 rtnh->rtnh_hops = nh->nh_weight - 1; 1064 rtnh->rtnh_ifindex = nh->nh_oif; 1065 1066 if (nh->nh_gw && 1067 nla_put_be32(skb, RTA_GATEWAY, nh->nh_gw)) 1068 goto nla_put_failure; 1069 #ifdef CONFIG_IP_ROUTE_CLASSID 1070 if (nh->nh_tclassid && 1071 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) 1072 goto nla_put_failure; 1073 #endif 1074 /* length of rtnetlink header + attributes */ 1075 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; 1076 } endfor_nexthops(fi); 1077 1078 nla_nest_end(skb, mp); 1079 } 1080 #endif 1081 return nlmsg_end(skb, nlh); 1082 1083 nla_put_failure: 1084 nlmsg_cancel(skb, nlh); 1085 return -EMSGSIZE; 1086 } 1087 1088 /* 1089 * Update FIB if: 1090 * - local address disappeared -> we must delete all the entries 1091 * referring to it. 1092 * - device went down -> we must shutdown all nexthops going via it. 1093 */ 1094 int fib_sync_down_addr(struct net *net, __be32 local) 1095 { 1096 int ret = 0; 1097 unsigned int hash = fib_laddr_hashfn(local); 1098 struct hlist_head *head = &fib_info_laddrhash[hash]; 1099 struct hlist_node *node; 1100 struct fib_info *fi; 1101 1102 if (fib_info_laddrhash == NULL || local == 0) 1103 return 0; 1104 1105 hlist_for_each_entry(fi, node, head, fib_lhash) { 1106 if (!net_eq(fi->fib_net, net)) 1107 continue; 1108 if (fi->fib_prefsrc == local) { 1109 fi->fib_flags |= RTNH_F_DEAD; 1110 ret++; 1111 } 1112 } 1113 return ret; 1114 } 1115 1116 int fib_sync_down_dev(struct net_device *dev, int force) 1117 { 1118 int ret = 0; 1119 int scope = RT_SCOPE_NOWHERE; 1120 struct fib_info *prev_fi = NULL; 1121 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1122 struct hlist_head *head = &fib_info_devhash[hash]; 1123 struct hlist_node *node; 1124 struct fib_nh *nh; 1125 1126 if (force) 1127 scope = -1; 1128 1129 hlist_for_each_entry(nh, node, head, nh_hash) { 1130 struct fib_info *fi = nh->nh_parent; 1131 int dead; 1132 1133 BUG_ON(!fi->fib_nhs); 1134 if (nh->nh_dev != dev || fi == prev_fi) 1135 continue; 1136 prev_fi = fi; 1137 dead = 0; 1138 change_nexthops(fi) { 1139 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1140 dead++; 1141 else if (nexthop_nh->nh_dev == dev && 1142 nexthop_nh->nh_scope != scope) { 1143 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1144 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1145 spin_lock_bh(&fib_multipath_lock); 1146 fi->fib_power -= nexthop_nh->nh_power; 1147 nexthop_nh->nh_power = 0; 1148 spin_unlock_bh(&fib_multipath_lock); 1149 #endif 1150 dead++; 1151 } 1152 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1153 if (force > 1 && nexthop_nh->nh_dev == dev) { 1154 dead = fi->fib_nhs; 1155 break; 1156 } 1157 #endif 1158 } endfor_nexthops(fi) 1159 if (dead == fi->fib_nhs) { 1160 fi->fib_flags |= RTNH_F_DEAD; 1161 ret++; 1162 } 1163 } 1164 1165 return ret; 1166 } 1167 1168 /* Must be invoked inside of an RCU protected region. */ 1169 void fib_select_default(struct fib_result *res) 1170 { 1171 struct fib_info *fi = NULL, *last_resort = NULL; 1172 struct list_head *fa_head = res->fa_head; 1173 struct fib_table *tb = res->table; 1174 int order = -1, last_idx = -1; 1175 struct fib_alias *fa; 1176 1177 list_for_each_entry_rcu(fa, fa_head, fa_list) { 1178 struct fib_info *next_fi = fa->fa_info; 1179 1180 if (next_fi->fib_scope != res->scope || 1181 fa->fa_type != RTN_UNICAST) 1182 continue; 1183 1184 if (next_fi->fib_priority > res->fi->fib_priority) 1185 break; 1186 if (!next_fi->fib_nh[0].nh_gw || 1187 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1188 continue; 1189 1190 fib_alias_accessed(fa); 1191 1192 if (fi == NULL) { 1193 if (next_fi != res->fi) 1194 break; 1195 } else if (!fib_detect_death(fi, order, &last_resort, 1196 &last_idx, tb->tb_default)) { 1197 fib_result_assign(res, fi); 1198 tb->tb_default = order; 1199 goto out; 1200 } 1201 fi = next_fi; 1202 order++; 1203 } 1204 1205 if (order <= 0 || fi == NULL) { 1206 tb->tb_default = -1; 1207 goto out; 1208 } 1209 1210 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1211 tb->tb_default)) { 1212 fib_result_assign(res, fi); 1213 tb->tb_default = order; 1214 goto out; 1215 } 1216 1217 if (last_idx >= 0) 1218 fib_result_assign(res, last_resort); 1219 tb->tb_default = last_idx; 1220 out: 1221 return; 1222 } 1223 1224 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1225 1226 /* 1227 * Dead device goes up. We wake up dead nexthops. 1228 * It takes sense only on multipath routes. 1229 */ 1230 int fib_sync_up(struct net_device *dev) 1231 { 1232 struct fib_info *prev_fi; 1233 unsigned int hash; 1234 struct hlist_head *head; 1235 struct hlist_node *node; 1236 struct fib_nh *nh; 1237 int ret; 1238 1239 if (!(dev->flags & IFF_UP)) 1240 return 0; 1241 1242 prev_fi = NULL; 1243 hash = fib_devindex_hashfn(dev->ifindex); 1244 head = &fib_info_devhash[hash]; 1245 ret = 0; 1246 1247 hlist_for_each_entry(nh, node, head, nh_hash) { 1248 struct fib_info *fi = nh->nh_parent; 1249 int alive; 1250 1251 BUG_ON(!fi->fib_nhs); 1252 if (nh->nh_dev != dev || fi == prev_fi) 1253 continue; 1254 1255 prev_fi = fi; 1256 alive = 0; 1257 change_nexthops(fi) { 1258 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { 1259 alive++; 1260 continue; 1261 } 1262 if (nexthop_nh->nh_dev == NULL || 1263 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1264 continue; 1265 if (nexthop_nh->nh_dev != dev || 1266 !__in_dev_get_rtnl(dev)) 1267 continue; 1268 alive++; 1269 spin_lock_bh(&fib_multipath_lock); 1270 nexthop_nh->nh_power = 0; 1271 nexthop_nh->nh_flags &= ~RTNH_F_DEAD; 1272 spin_unlock_bh(&fib_multipath_lock); 1273 } endfor_nexthops(fi) 1274 1275 if (alive > 0) { 1276 fi->fib_flags &= ~RTNH_F_DEAD; 1277 ret++; 1278 } 1279 } 1280 1281 return ret; 1282 } 1283 1284 /* 1285 * The algorithm is suboptimal, but it provides really 1286 * fair weighted route distribution. 1287 */ 1288 void fib_select_multipath(struct fib_result *res) 1289 { 1290 struct fib_info *fi = res->fi; 1291 int w; 1292 1293 spin_lock_bh(&fib_multipath_lock); 1294 if (fi->fib_power <= 0) { 1295 int power = 0; 1296 change_nexthops(fi) { 1297 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { 1298 power += nexthop_nh->nh_weight; 1299 nexthop_nh->nh_power = nexthop_nh->nh_weight; 1300 } 1301 } endfor_nexthops(fi); 1302 fi->fib_power = power; 1303 if (power <= 0) { 1304 spin_unlock_bh(&fib_multipath_lock); 1305 /* Race condition: route has just become dead. */ 1306 res->nh_sel = 0; 1307 return; 1308 } 1309 } 1310 1311 1312 /* w should be random number [0..fi->fib_power-1], 1313 * it is pretty bad approximation. 1314 */ 1315 1316 w = jiffies % fi->fib_power; 1317 1318 change_nexthops(fi) { 1319 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) && 1320 nexthop_nh->nh_power) { 1321 w -= nexthop_nh->nh_power; 1322 if (w <= 0) { 1323 nexthop_nh->nh_power--; 1324 fi->fib_power--; 1325 res->nh_sel = nhsel; 1326 spin_unlock_bh(&fib_multipath_lock); 1327 return; 1328 } 1329 } 1330 } endfor_nexthops(fi); 1331 1332 /* Race condition: route has just become dead. */ 1333 res->nh_sel = 0; 1334 spin_unlock_bh(&fib_multipath_lock); 1335 } 1336 #endif 1337