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_input); 173 rt_fibinfo_free(&fnhe->fnhe_rth_output); 174 175 kfree(fnhe); 176 177 fnhe = next; 178 } 179 } 180 kfree(hash); 181 } 182 183 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) 184 { 185 int cpu; 186 187 if (!rtp) 188 return; 189 190 for_each_possible_cpu(cpu) { 191 struct rtable *rt; 192 193 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); 194 if (rt) 195 dst_free(&rt->dst); 196 } 197 free_percpu(rtp); 198 } 199 200 /* Release a nexthop info record */ 201 static void free_fib_info_rcu(struct rcu_head *head) 202 { 203 struct fib_info *fi = container_of(head, struct fib_info, rcu); 204 205 change_nexthops(fi) { 206 if (nexthop_nh->nh_dev) 207 dev_put(nexthop_nh->nh_dev); 208 if (nexthop_nh->nh_exceptions) 209 free_nh_exceptions(nexthop_nh); 210 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); 211 rt_fibinfo_free(&nexthop_nh->nh_rth_input); 212 } endfor_nexthops(fi); 213 214 release_net(fi->fib_net); 215 if (fi->fib_metrics != (u32 *) dst_default_metrics) 216 kfree(fi->fib_metrics); 217 kfree(fi); 218 } 219 220 void free_fib_info(struct fib_info *fi) 221 { 222 if (fi->fib_dead == 0) { 223 pr_warn("Freeing alive fib_info %p\n", fi); 224 return; 225 } 226 fib_info_cnt--; 227 #ifdef CONFIG_IP_ROUTE_CLASSID 228 change_nexthops(fi) { 229 if (nexthop_nh->nh_tclassid) 230 fi->fib_net->ipv4.fib_num_tclassid_users--; 231 } endfor_nexthops(fi); 232 #endif 233 call_rcu(&fi->rcu, free_fib_info_rcu); 234 } 235 236 void fib_release_info(struct fib_info *fi) 237 { 238 spin_lock_bh(&fib_info_lock); 239 if (fi && --fi->fib_treeref == 0) { 240 hlist_del(&fi->fib_hash); 241 if (fi->fib_prefsrc) 242 hlist_del(&fi->fib_lhash); 243 change_nexthops(fi) { 244 if (!nexthop_nh->nh_dev) 245 continue; 246 hlist_del(&nexthop_nh->nh_hash); 247 } endfor_nexthops(fi) 248 fi->fib_dead = 1; 249 fib_info_put(fi); 250 } 251 spin_unlock_bh(&fib_info_lock); 252 } 253 254 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) 255 { 256 const struct fib_nh *onh = ofi->fib_nh; 257 258 for_nexthops(fi) { 259 if (nh->nh_oif != onh->nh_oif || 260 nh->nh_gw != onh->nh_gw || 261 nh->nh_scope != onh->nh_scope || 262 #ifdef CONFIG_IP_ROUTE_MULTIPATH 263 nh->nh_weight != onh->nh_weight || 264 #endif 265 #ifdef CONFIG_IP_ROUTE_CLASSID 266 nh->nh_tclassid != onh->nh_tclassid || 267 #endif 268 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD)) 269 return -1; 270 onh++; 271 } endfor_nexthops(fi); 272 return 0; 273 } 274 275 static inline unsigned int fib_devindex_hashfn(unsigned int val) 276 { 277 unsigned int mask = DEVINDEX_HASHSIZE - 1; 278 279 return (val ^ 280 (val >> DEVINDEX_HASHBITS) ^ 281 (val >> (DEVINDEX_HASHBITS * 2))) & mask; 282 } 283 284 static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 285 { 286 unsigned int mask = (fib_info_hash_size - 1); 287 unsigned int val = fi->fib_nhs; 288 289 val ^= (fi->fib_protocol << 8) | fi->fib_scope; 290 val ^= (__force u32)fi->fib_prefsrc; 291 val ^= fi->fib_priority; 292 for_nexthops(fi) { 293 val ^= fib_devindex_hashfn(nh->nh_oif); 294 } endfor_nexthops(fi) 295 296 return (val ^ (val >> 7) ^ (val >> 12)) & mask; 297 } 298 299 static struct fib_info *fib_find_info(const struct fib_info *nfi) 300 { 301 struct hlist_head *head; 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, 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 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, 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, const 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->portid, 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->portid, 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 static int fib_detect_death(struct fib_info *fi, int order, 430 struct fib_info **last_resort, int *last_idx, 431 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 *n; 725 struct fib_info *fi; 726 727 hlist_for_each_entry_safe(fi, 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 *n; 743 struct fib_info *fi; 744 745 hlist_for_each_entry_safe(fi, 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 fib_info *fi; 1100 1101 if (fib_info_laddrhash == NULL || local == 0) 1102 return 0; 1103 1104 hlist_for_each_entry(fi, head, fib_lhash) { 1105 if (!net_eq(fi->fib_net, net)) 1106 continue; 1107 if (fi->fib_prefsrc == local) { 1108 fi->fib_flags |= RTNH_F_DEAD; 1109 ret++; 1110 } 1111 } 1112 return ret; 1113 } 1114 1115 int fib_sync_down_dev(struct net_device *dev, int force) 1116 { 1117 int ret = 0; 1118 int scope = RT_SCOPE_NOWHERE; 1119 struct fib_info *prev_fi = NULL; 1120 unsigned int hash = fib_devindex_hashfn(dev->ifindex); 1121 struct hlist_head *head = &fib_info_devhash[hash]; 1122 struct fib_nh *nh; 1123 1124 if (force) 1125 scope = -1; 1126 1127 hlist_for_each_entry(nh, head, nh_hash) { 1128 struct fib_info *fi = nh->nh_parent; 1129 int dead; 1130 1131 BUG_ON(!fi->fib_nhs); 1132 if (nh->nh_dev != dev || fi == prev_fi) 1133 continue; 1134 prev_fi = fi; 1135 dead = 0; 1136 change_nexthops(fi) { 1137 if (nexthop_nh->nh_flags & RTNH_F_DEAD) 1138 dead++; 1139 else if (nexthop_nh->nh_dev == dev && 1140 nexthop_nh->nh_scope != scope) { 1141 nexthop_nh->nh_flags |= RTNH_F_DEAD; 1142 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1143 spin_lock_bh(&fib_multipath_lock); 1144 fi->fib_power -= nexthop_nh->nh_power; 1145 nexthop_nh->nh_power = 0; 1146 spin_unlock_bh(&fib_multipath_lock); 1147 #endif 1148 dead++; 1149 } 1150 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1151 if (force > 1 && nexthop_nh->nh_dev == dev) { 1152 dead = fi->fib_nhs; 1153 break; 1154 } 1155 #endif 1156 } endfor_nexthops(fi) 1157 if (dead == fi->fib_nhs) { 1158 fi->fib_flags |= RTNH_F_DEAD; 1159 ret++; 1160 } 1161 } 1162 1163 return ret; 1164 } 1165 1166 /* Must be invoked inside of an RCU protected region. */ 1167 void fib_select_default(struct fib_result *res) 1168 { 1169 struct fib_info *fi = NULL, *last_resort = NULL; 1170 struct list_head *fa_head = res->fa_head; 1171 struct fib_table *tb = res->table; 1172 int order = -1, last_idx = -1; 1173 struct fib_alias *fa; 1174 1175 list_for_each_entry_rcu(fa, fa_head, fa_list) { 1176 struct fib_info *next_fi = fa->fa_info; 1177 1178 if (next_fi->fib_scope != res->scope || 1179 fa->fa_type != RTN_UNICAST) 1180 continue; 1181 1182 if (next_fi->fib_priority > res->fi->fib_priority) 1183 break; 1184 if (!next_fi->fib_nh[0].nh_gw || 1185 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK) 1186 continue; 1187 1188 fib_alias_accessed(fa); 1189 1190 if (fi == NULL) { 1191 if (next_fi != res->fi) 1192 break; 1193 } else if (!fib_detect_death(fi, order, &last_resort, 1194 &last_idx, tb->tb_default)) { 1195 fib_result_assign(res, fi); 1196 tb->tb_default = order; 1197 goto out; 1198 } 1199 fi = next_fi; 1200 order++; 1201 } 1202 1203 if (order <= 0 || fi == NULL) { 1204 tb->tb_default = -1; 1205 goto out; 1206 } 1207 1208 if (!fib_detect_death(fi, order, &last_resort, &last_idx, 1209 tb->tb_default)) { 1210 fib_result_assign(res, fi); 1211 tb->tb_default = order; 1212 goto out; 1213 } 1214 1215 if (last_idx >= 0) 1216 fib_result_assign(res, last_resort); 1217 tb->tb_default = last_idx; 1218 out: 1219 return; 1220 } 1221 1222 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1223 1224 /* 1225 * Dead device goes up. We wake up dead nexthops. 1226 * It takes sense only on multipath routes. 1227 */ 1228 int fib_sync_up(struct net_device *dev) 1229 { 1230 struct fib_info *prev_fi; 1231 unsigned int hash; 1232 struct hlist_head *head; 1233 struct fib_nh *nh; 1234 int ret; 1235 1236 if (!(dev->flags & IFF_UP)) 1237 return 0; 1238 1239 prev_fi = NULL; 1240 hash = fib_devindex_hashfn(dev->ifindex); 1241 head = &fib_info_devhash[hash]; 1242 ret = 0; 1243 1244 hlist_for_each_entry(nh, head, nh_hash) { 1245 struct fib_info *fi = nh->nh_parent; 1246 int alive; 1247 1248 BUG_ON(!fi->fib_nhs); 1249 if (nh->nh_dev != dev || fi == prev_fi) 1250 continue; 1251 1252 prev_fi = fi; 1253 alive = 0; 1254 change_nexthops(fi) { 1255 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { 1256 alive++; 1257 continue; 1258 } 1259 if (nexthop_nh->nh_dev == NULL || 1260 !(nexthop_nh->nh_dev->flags & IFF_UP)) 1261 continue; 1262 if (nexthop_nh->nh_dev != dev || 1263 !__in_dev_get_rtnl(dev)) 1264 continue; 1265 alive++; 1266 spin_lock_bh(&fib_multipath_lock); 1267 nexthop_nh->nh_power = 0; 1268 nexthop_nh->nh_flags &= ~RTNH_F_DEAD; 1269 spin_unlock_bh(&fib_multipath_lock); 1270 } endfor_nexthops(fi) 1271 1272 if (alive > 0) { 1273 fi->fib_flags &= ~RTNH_F_DEAD; 1274 ret++; 1275 } 1276 } 1277 1278 return ret; 1279 } 1280 1281 /* 1282 * The algorithm is suboptimal, but it provides really 1283 * fair weighted route distribution. 1284 */ 1285 void fib_select_multipath(struct fib_result *res) 1286 { 1287 struct fib_info *fi = res->fi; 1288 int w; 1289 1290 spin_lock_bh(&fib_multipath_lock); 1291 if (fi->fib_power <= 0) { 1292 int power = 0; 1293 change_nexthops(fi) { 1294 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { 1295 power += nexthop_nh->nh_weight; 1296 nexthop_nh->nh_power = nexthop_nh->nh_weight; 1297 } 1298 } endfor_nexthops(fi); 1299 fi->fib_power = power; 1300 if (power <= 0) { 1301 spin_unlock_bh(&fib_multipath_lock); 1302 /* Race condition: route has just become dead. */ 1303 res->nh_sel = 0; 1304 return; 1305 } 1306 } 1307 1308 1309 /* w should be random number [0..fi->fib_power-1], 1310 * it is pretty bad approximation. 1311 */ 1312 1313 w = jiffies % fi->fib_power; 1314 1315 change_nexthops(fi) { 1316 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) && 1317 nexthop_nh->nh_power) { 1318 w -= nexthop_nh->nh_power; 1319 if (w <= 0) { 1320 nexthop_nh->nh_power--; 1321 fi->fib_power--; 1322 res->nh_sel = nhsel; 1323 spin_unlock_bh(&fib_multipath_lock); 1324 return; 1325 } 1326 } 1327 } endfor_nexthops(fi); 1328 1329 /* Race condition: route has just become dead. */ 1330 res->nh_sel = 0; 1331 spin_unlock_bh(&fib_multipath_lock); 1332 } 1333 #endif 1334