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