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 * ROUTE - implementation of the IP router. 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Alan Cox, <gw4pts@gw4pts.ampr.org> 11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 13 * 14 * Fixes: 15 * Alan Cox : Verify area fixes. 16 * Alan Cox : cli() protects routing changes 17 * Rui Oliveira : ICMP routing table updates 18 * (rco@di.uminho.pt) Routing table insertion and update 19 * Linus Torvalds : Rewrote bits to be sensible 20 * Alan Cox : Added BSD route gw semantics 21 * Alan Cox : Super /proc >4K 22 * Alan Cox : MTU in route table 23 * Alan Cox : MSS actually. Also added the window 24 * clamper. 25 * Sam Lantinga : Fixed route matching in rt_del() 26 * Alan Cox : Routing cache support. 27 * Alan Cox : Removed compatibility cruft. 28 * Alan Cox : RTF_REJECT support. 29 * Alan Cox : TCP irtt support. 30 * Jonathan Naylor : Added Metric support. 31 * Miquel van Smoorenburg : BSD API fixes. 32 * Miquel van Smoorenburg : Metrics. 33 * Alan Cox : Use __u32 properly 34 * Alan Cox : Aligned routing errors more closely with BSD 35 * our system is still very different. 36 * Alan Cox : Faster /proc handling 37 * Alexey Kuznetsov : Massive rework to support tree based routing, 38 * routing caches and better behaviour. 39 * 40 * Olaf Erb : irtt wasn't being copied right. 41 * Bjorn Ekwall : Kerneld route support. 42 * Alan Cox : Multicast fixed (I hope) 43 * Pavel Krauz : Limited broadcast fixed 44 * Mike McLagan : Routing by source 45 * Alexey Kuznetsov : End of old history. Split to fib.c and 46 * route.c and rewritten from scratch. 47 * Andi Kleen : Load-limit warning messages. 48 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 52 * Marc Boucher : routing by fwmark 53 * Robert Olsson : Added rt_cache statistics 54 * Arnaldo C. Melo : Convert proc stuff to seq_file 55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 57 * Ilia Sotnikov : Removed TOS from hash calculations 58 * 59 * This program is free software; you can redistribute it and/or 60 * modify it under the terms of the GNU General Public License 61 * as published by the Free Software Foundation; either version 62 * 2 of the License, or (at your option) any later version. 63 */ 64 65 #define pr_fmt(fmt) "IPv4: " fmt 66 67 #include <linux/module.h> 68 #include <asm/uaccess.h> 69 #include <linux/bitops.h> 70 #include <linux/types.h> 71 #include <linux/kernel.h> 72 #include <linux/mm.h> 73 #include <linux/string.h> 74 #include <linux/socket.h> 75 #include <linux/sockios.h> 76 #include <linux/errno.h> 77 #include <linux/in.h> 78 #include <linux/inet.h> 79 #include <linux/netdevice.h> 80 #include <linux/proc_fs.h> 81 #include <linux/init.h> 82 #include <linux/skbuff.h> 83 #include <linux/inetdevice.h> 84 #include <linux/igmp.h> 85 #include <linux/pkt_sched.h> 86 #include <linux/mroute.h> 87 #include <linux/netfilter_ipv4.h> 88 #include <linux/random.h> 89 #include <linux/rcupdate.h> 90 #include <linux/times.h> 91 #include <linux/slab.h> 92 #include <linux/jhash.h> 93 #include <net/dst.h> 94 #include <net/dst_metadata.h> 95 #include <net/net_namespace.h> 96 #include <net/protocol.h> 97 #include <net/ip.h> 98 #include <net/route.h> 99 #include <net/inetpeer.h> 100 #include <net/sock.h> 101 #include <net/ip_fib.h> 102 #include <net/arp.h> 103 #include <net/tcp.h> 104 #include <net/icmp.h> 105 #include <net/xfrm.h> 106 #include <net/lwtunnel.h> 107 #include <net/netevent.h> 108 #include <net/rtnetlink.h> 109 #ifdef CONFIG_SYSCTL 110 #include <linux/sysctl.h> 111 #include <linux/kmemleak.h> 112 #endif 113 #include <net/secure_seq.h> 114 #include <net/ip_tunnels.h> 115 #include <net/l3mdev.h> 116 117 #define RT_FL_TOS(oldflp4) \ 118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 119 120 #define RT_GC_TIMEOUT (300*HZ) 121 122 static int ip_rt_max_size; 123 static int ip_rt_redirect_number __read_mostly = 9; 124 static int ip_rt_redirect_load __read_mostly = HZ / 50; 125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 126 static int ip_rt_error_cost __read_mostly = HZ; 127 static int ip_rt_error_burst __read_mostly = 5 * HZ; 128 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 130 static int ip_rt_min_advmss __read_mostly = 256; 131 132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 133 /* 134 * Interface to generic destination cache. 135 */ 136 137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 139 static unsigned int ipv4_mtu(const struct dst_entry *dst); 140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 141 static void ipv4_link_failure(struct sk_buff *skb); 142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 143 struct sk_buff *skb, u32 mtu); 144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 145 struct sk_buff *skb); 146 static void ipv4_dst_destroy(struct dst_entry *dst); 147 148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 149 { 150 WARN_ON(1); 151 return NULL; 152 } 153 154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 155 struct sk_buff *skb, 156 const void *daddr); 157 158 static struct dst_ops ipv4_dst_ops = { 159 .family = AF_INET, 160 .check = ipv4_dst_check, 161 .default_advmss = ipv4_default_advmss, 162 .mtu = ipv4_mtu, 163 .cow_metrics = ipv4_cow_metrics, 164 .destroy = ipv4_dst_destroy, 165 .negative_advice = ipv4_negative_advice, 166 .link_failure = ipv4_link_failure, 167 .update_pmtu = ip_rt_update_pmtu, 168 .redirect = ip_do_redirect, 169 .local_out = __ip_local_out, 170 .neigh_lookup = ipv4_neigh_lookup, 171 }; 172 173 #define ECN_OR_COST(class) TC_PRIO_##class 174 175 const __u8 ip_tos2prio[16] = { 176 TC_PRIO_BESTEFFORT, 177 ECN_OR_COST(BESTEFFORT), 178 TC_PRIO_BESTEFFORT, 179 ECN_OR_COST(BESTEFFORT), 180 TC_PRIO_BULK, 181 ECN_OR_COST(BULK), 182 TC_PRIO_BULK, 183 ECN_OR_COST(BULK), 184 TC_PRIO_INTERACTIVE, 185 ECN_OR_COST(INTERACTIVE), 186 TC_PRIO_INTERACTIVE, 187 ECN_OR_COST(INTERACTIVE), 188 TC_PRIO_INTERACTIVE_BULK, 189 ECN_OR_COST(INTERACTIVE_BULK), 190 TC_PRIO_INTERACTIVE_BULK, 191 ECN_OR_COST(INTERACTIVE_BULK) 192 }; 193 EXPORT_SYMBOL(ip_tos2prio); 194 195 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 196 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 197 198 #ifdef CONFIG_PROC_FS 199 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 200 { 201 if (*pos) 202 return NULL; 203 return SEQ_START_TOKEN; 204 } 205 206 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 207 { 208 ++*pos; 209 return NULL; 210 } 211 212 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 213 { 214 } 215 216 static int rt_cache_seq_show(struct seq_file *seq, void *v) 217 { 218 if (v == SEQ_START_TOKEN) 219 seq_printf(seq, "%-127s\n", 220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 222 "HHUptod\tSpecDst"); 223 return 0; 224 } 225 226 static const struct seq_operations rt_cache_seq_ops = { 227 .start = rt_cache_seq_start, 228 .next = rt_cache_seq_next, 229 .stop = rt_cache_seq_stop, 230 .show = rt_cache_seq_show, 231 }; 232 233 static int rt_cache_seq_open(struct inode *inode, struct file *file) 234 { 235 return seq_open(file, &rt_cache_seq_ops); 236 } 237 238 static const struct file_operations rt_cache_seq_fops = { 239 .owner = THIS_MODULE, 240 .open = rt_cache_seq_open, 241 .read = seq_read, 242 .llseek = seq_lseek, 243 .release = seq_release, 244 }; 245 246 247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 248 { 249 int cpu; 250 251 if (*pos == 0) 252 return SEQ_START_TOKEN; 253 254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 255 if (!cpu_possible(cpu)) 256 continue; 257 *pos = cpu+1; 258 return &per_cpu(rt_cache_stat, cpu); 259 } 260 return NULL; 261 } 262 263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 264 { 265 int cpu; 266 267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 268 if (!cpu_possible(cpu)) 269 continue; 270 *pos = cpu+1; 271 return &per_cpu(rt_cache_stat, cpu); 272 } 273 return NULL; 274 275 } 276 277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 278 { 279 280 } 281 282 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 283 { 284 struct rt_cache_stat *st = v; 285 286 if (v == SEQ_START_TOKEN) { 287 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"); 288 return 0; 289 } 290 291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 293 dst_entries_get_slow(&ipv4_dst_ops), 294 0, /* st->in_hit */ 295 st->in_slow_tot, 296 st->in_slow_mc, 297 st->in_no_route, 298 st->in_brd, 299 st->in_martian_dst, 300 st->in_martian_src, 301 302 0, /* st->out_hit */ 303 st->out_slow_tot, 304 st->out_slow_mc, 305 306 0, /* st->gc_total */ 307 0, /* st->gc_ignored */ 308 0, /* st->gc_goal_miss */ 309 0, /* st->gc_dst_overflow */ 310 0, /* st->in_hlist_search */ 311 0 /* st->out_hlist_search */ 312 ); 313 return 0; 314 } 315 316 static const struct seq_operations rt_cpu_seq_ops = { 317 .start = rt_cpu_seq_start, 318 .next = rt_cpu_seq_next, 319 .stop = rt_cpu_seq_stop, 320 .show = rt_cpu_seq_show, 321 }; 322 323 324 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 325 { 326 return seq_open(file, &rt_cpu_seq_ops); 327 } 328 329 static const struct file_operations rt_cpu_seq_fops = { 330 .owner = THIS_MODULE, 331 .open = rt_cpu_seq_open, 332 .read = seq_read, 333 .llseek = seq_lseek, 334 .release = seq_release, 335 }; 336 337 #ifdef CONFIG_IP_ROUTE_CLASSID 338 static int rt_acct_proc_show(struct seq_file *m, void *v) 339 { 340 struct ip_rt_acct *dst, *src; 341 unsigned int i, j; 342 343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 344 if (!dst) 345 return -ENOMEM; 346 347 for_each_possible_cpu(i) { 348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 349 for (j = 0; j < 256; j++) { 350 dst[j].o_bytes += src[j].o_bytes; 351 dst[j].o_packets += src[j].o_packets; 352 dst[j].i_bytes += src[j].i_bytes; 353 dst[j].i_packets += src[j].i_packets; 354 } 355 } 356 357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 358 kfree(dst); 359 return 0; 360 } 361 362 static int rt_acct_proc_open(struct inode *inode, struct file *file) 363 { 364 return single_open(file, rt_acct_proc_show, NULL); 365 } 366 367 static const struct file_operations rt_acct_proc_fops = { 368 .owner = THIS_MODULE, 369 .open = rt_acct_proc_open, 370 .read = seq_read, 371 .llseek = seq_lseek, 372 .release = single_release, 373 }; 374 #endif 375 376 static int __net_init ip_rt_do_proc_init(struct net *net) 377 { 378 struct proc_dir_entry *pde; 379 380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net, 381 &rt_cache_seq_fops); 382 if (!pde) 383 goto err1; 384 385 pde = proc_create("rt_cache", S_IRUGO, 386 net->proc_net_stat, &rt_cpu_seq_fops); 387 if (!pde) 388 goto err2; 389 390 #ifdef CONFIG_IP_ROUTE_CLASSID 391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops); 392 if (!pde) 393 goto err3; 394 #endif 395 return 0; 396 397 #ifdef CONFIG_IP_ROUTE_CLASSID 398 err3: 399 remove_proc_entry("rt_cache", net->proc_net_stat); 400 #endif 401 err2: 402 remove_proc_entry("rt_cache", net->proc_net); 403 err1: 404 return -ENOMEM; 405 } 406 407 static void __net_exit ip_rt_do_proc_exit(struct net *net) 408 { 409 remove_proc_entry("rt_cache", net->proc_net_stat); 410 remove_proc_entry("rt_cache", net->proc_net); 411 #ifdef CONFIG_IP_ROUTE_CLASSID 412 remove_proc_entry("rt_acct", net->proc_net); 413 #endif 414 } 415 416 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 417 .init = ip_rt_do_proc_init, 418 .exit = ip_rt_do_proc_exit, 419 }; 420 421 static int __init ip_rt_proc_init(void) 422 { 423 return register_pernet_subsys(&ip_rt_proc_ops); 424 } 425 426 #else 427 static inline int ip_rt_proc_init(void) 428 { 429 return 0; 430 } 431 #endif /* CONFIG_PROC_FS */ 432 433 static inline bool rt_is_expired(const struct rtable *rth) 434 { 435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 436 } 437 438 void rt_cache_flush(struct net *net) 439 { 440 rt_genid_bump_ipv4(net); 441 } 442 443 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 444 struct sk_buff *skb, 445 const void *daddr) 446 { 447 struct net_device *dev = dst->dev; 448 const __be32 *pkey = daddr; 449 const struct rtable *rt; 450 struct neighbour *n; 451 452 rt = (const struct rtable *) dst; 453 if (rt->rt_gateway) 454 pkey = (const __be32 *) &rt->rt_gateway; 455 else if (skb) 456 pkey = &ip_hdr(skb)->daddr; 457 458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); 459 if (n) 460 return n; 461 return neigh_create(&arp_tbl, pkey, dev); 462 } 463 464 #define IP_IDENTS_SZ 2048u 465 466 static atomic_t *ip_idents __read_mostly; 467 static u32 *ip_tstamps __read_mostly; 468 469 /* In order to protect privacy, we add a perturbation to identifiers 470 * if one generator is seldom used. This makes hard for an attacker 471 * to infer how many packets were sent between two points in time. 472 */ 473 u32 ip_idents_reserve(u32 hash, int segs) 474 { 475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 477 u32 old = ACCESS_ONCE(*p_tstamp); 478 u32 now = (u32)jiffies; 479 u32 new, delta = 0; 480 481 if (old != now && cmpxchg(p_tstamp, old, now) == old) 482 delta = prandom_u32_max(now - old); 483 484 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 485 do { 486 old = (u32)atomic_read(p_id); 487 new = old + delta + segs; 488 } while (atomic_cmpxchg(p_id, old, new) != old); 489 490 return new - segs; 491 } 492 EXPORT_SYMBOL(ip_idents_reserve); 493 494 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 495 { 496 static u32 ip_idents_hashrnd __read_mostly; 497 u32 hash, id; 498 499 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); 500 501 hash = jhash_3words((__force u32)iph->daddr, 502 (__force u32)iph->saddr, 503 iph->protocol ^ net_hash_mix(net), 504 ip_idents_hashrnd); 505 id = ip_idents_reserve(hash, segs); 506 iph->id = htons(id); 507 } 508 EXPORT_SYMBOL(__ip_select_ident); 509 510 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk, 511 const struct iphdr *iph, 512 int oif, u8 tos, 513 u8 prot, u32 mark, int flow_flags) 514 { 515 if (sk) { 516 const struct inet_sock *inet = inet_sk(sk); 517 518 oif = sk->sk_bound_dev_if; 519 mark = sk->sk_mark; 520 tos = RT_CONN_FLAGS(sk); 521 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 522 } 523 flowi4_init_output(fl4, oif, mark, tos, 524 RT_SCOPE_UNIVERSE, prot, 525 flow_flags, 526 iph->daddr, iph->saddr, 0, 0); 527 } 528 529 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 530 const struct sock *sk) 531 { 532 const struct iphdr *iph = ip_hdr(skb); 533 int oif = skb->dev->ifindex; 534 u8 tos = RT_TOS(iph->tos); 535 u8 prot = iph->protocol; 536 u32 mark = skb->mark; 537 538 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0); 539 } 540 541 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 542 { 543 const struct inet_sock *inet = inet_sk(sk); 544 const struct ip_options_rcu *inet_opt; 545 __be32 daddr = inet->inet_daddr; 546 547 rcu_read_lock(); 548 inet_opt = rcu_dereference(inet->inet_opt); 549 if (inet_opt && inet_opt->opt.srr) 550 daddr = inet_opt->opt.faddr; 551 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 552 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 553 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 554 inet_sk_flowi_flags(sk), 555 daddr, inet->inet_saddr, 0, 0); 556 rcu_read_unlock(); 557 } 558 559 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 560 const struct sk_buff *skb) 561 { 562 if (skb) 563 build_skb_flow_key(fl4, skb, sk); 564 else 565 build_sk_flow_key(fl4, sk); 566 } 567 568 static inline void rt_free(struct rtable *rt) 569 { 570 call_rcu(&rt->dst.rcu_head, dst_rcu_free); 571 } 572 573 static DEFINE_SPINLOCK(fnhe_lock); 574 575 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 576 { 577 struct rtable *rt; 578 579 rt = rcu_dereference(fnhe->fnhe_rth_input); 580 if (rt) { 581 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 582 rt_free(rt); 583 } 584 rt = rcu_dereference(fnhe->fnhe_rth_output); 585 if (rt) { 586 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 587 rt_free(rt); 588 } 589 } 590 591 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 592 { 593 struct fib_nh_exception *fnhe, *oldest; 594 595 oldest = rcu_dereference(hash->chain); 596 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 597 fnhe = rcu_dereference(fnhe->fnhe_next)) { 598 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 599 oldest = fnhe; 600 } 601 fnhe_flush_routes(oldest); 602 return oldest; 603 } 604 605 static inline u32 fnhe_hashfun(__be32 daddr) 606 { 607 static u32 fnhe_hashrnd __read_mostly; 608 u32 hval; 609 610 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 611 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 612 return hash_32(hval, FNHE_HASH_SHIFT); 613 } 614 615 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 616 { 617 rt->rt_pmtu = fnhe->fnhe_pmtu; 618 rt->dst.expires = fnhe->fnhe_expires; 619 620 if (fnhe->fnhe_gw) { 621 rt->rt_flags |= RTCF_REDIRECTED; 622 rt->rt_gateway = fnhe->fnhe_gw; 623 rt->rt_uses_gateway = 1; 624 } 625 } 626 627 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 628 u32 pmtu, unsigned long expires) 629 { 630 struct fnhe_hash_bucket *hash; 631 struct fib_nh_exception *fnhe; 632 struct rtable *rt; 633 unsigned int i; 634 int depth; 635 u32 hval = fnhe_hashfun(daddr); 636 637 spin_lock_bh(&fnhe_lock); 638 639 hash = rcu_dereference(nh->nh_exceptions); 640 if (!hash) { 641 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 642 if (!hash) 643 goto out_unlock; 644 rcu_assign_pointer(nh->nh_exceptions, hash); 645 } 646 647 hash += hval; 648 649 depth = 0; 650 for (fnhe = rcu_dereference(hash->chain); fnhe; 651 fnhe = rcu_dereference(fnhe->fnhe_next)) { 652 if (fnhe->fnhe_daddr == daddr) 653 break; 654 depth++; 655 } 656 657 if (fnhe) { 658 if (gw) 659 fnhe->fnhe_gw = gw; 660 if (pmtu) { 661 fnhe->fnhe_pmtu = pmtu; 662 fnhe->fnhe_expires = max(1UL, expires); 663 } 664 /* Update all cached dsts too */ 665 rt = rcu_dereference(fnhe->fnhe_rth_input); 666 if (rt) 667 fill_route_from_fnhe(rt, fnhe); 668 rt = rcu_dereference(fnhe->fnhe_rth_output); 669 if (rt) 670 fill_route_from_fnhe(rt, fnhe); 671 } else { 672 if (depth > FNHE_RECLAIM_DEPTH) 673 fnhe = fnhe_oldest(hash); 674 else { 675 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 676 if (!fnhe) 677 goto out_unlock; 678 679 fnhe->fnhe_next = hash->chain; 680 rcu_assign_pointer(hash->chain, fnhe); 681 } 682 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev)); 683 fnhe->fnhe_daddr = daddr; 684 fnhe->fnhe_gw = gw; 685 fnhe->fnhe_pmtu = pmtu; 686 fnhe->fnhe_expires = expires; 687 688 /* Exception created; mark the cached routes for the nexthop 689 * stale, so anyone caching it rechecks if this exception 690 * applies to them. 691 */ 692 rt = rcu_dereference(nh->nh_rth_input); 693 if (rt) 694 rt->dst.obsolete = DST_OBSOLETE_KILL; 695 696 for_each_possible_cpu(i) { 697 struct rtable __rcu **prt; 698 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 699 rt = rcu_dereference(*prt); 700 if (rt) 701 rt->dst.obsolete = DST_OBSOLETE_KILL; 702 } 703 } 704 705 fnhe->fnhe_stamp = jiffies; 706 707 out_unlock: 708 spin_unlock_bh(&fnhe_lock); 709 } 710 711 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 712 bool kill_route) 713 { 714 __be32 new_gw = icmp_hdr(skb)->un.gateway; 715 __be32 old_gw = ip_hdr(skb)->saddr; 716 struct net_device *dev = skb->dev; 717 struct in_device *in_dev; 718 struct fib_result res; 719 struct neighbour *n; 720 struct net *net; 721 722 switch (icmp_hdr(skb)->code & 7) { 723 case ICMP_REDIR_NET: 724 case ICMP_REDIR_NETTOS: 725 case ICMP_REDIR_HOST: 726 case ICMP_REDIR_HOSTTOS: 727 break; 728 729 default: 730 return; 731 } 732 733 if (rt->rt_gateway != old_gw) 734 return; 735 736 in_dev = __in_dev_get_rcu(dev); 737 if (!in_dev) 738 return; 739 740 net = dev_net(dev); 741 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 742 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 743 ipv4_is_zeronet(new_gw)) 744 goto reject_redirect; 745 746 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 747 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 748 goto reject_redirect; 749 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 750 goto reject_redirect; 751 } else { 752 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 753 goto reject_redirect; 754 } 755 756 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 757 if (!n) 758 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 759 if (!IS_ERR(n)) { 760 if (!(n->nud_state & NUD_VALID)) { 761 neigh_event_send(n, NULL); 762 } else { 763 if (fib_lookup(net, fl4, &res, 0) == 0) { 764 struct fib_nh *nh = &FIB_RES_NH(res); 765 766 update_or_create_fnhe(nh, fl4->daddr, new_gw, 767 0, jiffies + ip_rt_gc_timeout); 768 } 769 if (kill_route) 770 rt->dst.obsolete = DST_OBSOLETE_KILL; 771 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 772 } 773 neigh_release(n); 774 } 775 return; 776 777 reject_redirect: 778 #ifdef CONFIG_IP_ROUTE_VERBOSE 779 if (IN_DEV_LOG_MARTIANS(in_dev)) { 780 const struct iphdr *iph = (const struct iphdr *) skb->data; 781 __be32 daddr = iph->daddr; 782 __be32 saddr = iph->saddr; 783 784 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 785 " Advised path = %pI4 -> %pI4\n", 786 &old_gw, dev->name, &new_gw, 787 &saddr, &daddr); 788 } 789 #endif 790 ; 791 } 792 793 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 794 { 795 struct rtable *rt; 796 struct flowi4 fl4; 797 const struct iphdr *iph = (const struct iphdr *) skb->data; 798 int oif = skb->dev->ifindex; 799 u8 tos = RT_TOS(iph->tos); 800 u8 prot = iph->protocol; 801 u32 mark = skb->mark; 802 803 rt = (struct rtable *) dst; 804 805 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0); 806 __ip_do_redirect(rt, skb, &fl4, true); 807 } 808 809 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 810 { 811 struct rtable *rt = (struct rtable *)dst; 812 struct dst_entry *ret = dst; 813 814 if (rt) { 815 if (dst->obsolete > 0) { 816 ip_rt_put(rt); 817 ret = NULL; 818 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 819 rt->dst.expires) { 820 ip_rt_put(rt); 821 ret = NULL; 822 } 823 } 824 return ret; 825 } 826 827 /* 828 * Algorithm: 829 * 1. The first ip_rt_redirect_number redirects are sent 830 * with exponential backoff, then we stop sending them at all, 831 * assuming that the host ignores our redirects. 832 * 2. If we did not see packets requiring redirects 833 * during ip_rt_redirect_silence, we assume that the host 834 * forgot redirected route and start to send redirects again. 835 * 836 * This algorithm is much cheaper and more intelligent than dumb load limiting 837 * in icmp.c. 838 * 839 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 840 * and "frag. need" (breaks PMTU discovery) in icmp.c. 841 */ 842 843 void ip_rt_send_redirect(struct sk_buff *skb) 844 { 845 struct rtable *rt = skb_rtable(skb); 846 struct in_device *in_dev; 847 struct inet_peer *peer; 848 struct net *net; 849 int log_martians; 850 int vif; 851 852 rcu_read_lock(); 853 in_dev = __in_dev_get_rcu(rt->dst.dev); 854 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 855 rcu_read_unlock(); 856 return; 857 } 858 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 859 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 860 rcu_read_unlock(); 861 862 net = dev_net(rt->dst.dev); 863 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 864 if (!peer) { 865 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 866 rt_nexthop(rt, ip_hdr(skb)->daddr)); 867 return; 868 } 869 870 /* No redirected packets during ip_rt_redirect_silence; 871 * reset the algorithm. 872 */ 873 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 874 peer->rate_tokens = 0; 875 876 /* Too many ignored redirects; do not send anything 877 * set dst.rate_last to the last seen redirected packet. 878 */ 879 if (peer->rate_tokens >= ip_rt_redirect_number) { 880 peer->rate_last = jiffies; 881 goto out_put_peer; 882 } 883 884 /* Check for load limit; set rate_last to the latest sent 885 * redirect. 886 */ 887 if (peer->rate_tokens == 0 || 888 time_after(jiffies, 889 (peer->rate_last + 890 (ip_rt_redirect_load << peer->rate_tokens)))) { 891 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 892 893 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 894 peer->rate_last = jiffies; 895 ++peer->rate_tokens; 896 #ifdef CONFIG_IP_ROUTE_VERBOSE 897 if (log_martians && 898 peer->rate_tokens == ip_rt_redirect_number) 899 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 900 &ip_hdr(skb)->saddr, inet_iif(skb), 901 &ip_hdr(skb)->daddr, &gw); 902 #endif 903 } 904 out_put_peer: 905 inet_putpeer(peer); 906 } 907 908 static int ip_error(struct sk_buff *skb) 909 { 910 struct in_device *in_dev = __in_dev_get_rcu(skb->dev); 911 struct rtable *rt = skb_rtable(skb); 912 struct inet_peer *peer; 913 unsigned long now; 914 struct net *net; 915 bool send; 916 int code; 917 918 /* IP on this device is disabled. */ 919 if (!in_dev) 920 goto out; 921 922 net = dev_net(rt->dst.dev); 923 if (!IN_DEV_FORWARD(in_dev)) { 924 switch (rt->dst.error) { 925 case EHOSTUNREACH: 926 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 927 break; 928 929 case ENETUNREACH: 930 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 931 break; 932 } 933 goto out; 934 } 935 936 switch (rt->dst.error) { 937 case EINVAL: 938 default: 939 goto out; 940 case EHOSTUNREACH: 941 code = ICMP_HOST_UNREACH; 942 break; 943 case ENETUNREACH: 944 code = ICMP_NET_UNREACH; 945 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 946 break; 947 case EACCES: 948 code = ICMP_PKT_FILTERED; 949 break; 950 } 951 952 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 953 l3mdev_master_ifindex(skb->dev), 1); 954 955 send = true; 956 if (peer) { 957 now = jiffies; 958 peer->rate_tokens += now - peer->rate_last; 959 if (peer->rate_tokens > ip_rt_error_burst) 960 peer->rate_tokens = ip_rt_error_burst; 961 peer->rate_last = now; 962 if (peer->rate_tokens >= ip_rt_error_cost) 963 peer->rate_tokens -= ip_rt_error_cost; 964 else 965 send = false; 966 inet_putpeer(peer); 967 } 968 if (send) 969 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 970 971 out: kfree_skb(skb); 972 return 0; 973 } 974 975 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 976 { 977 struct dst_entry *dst = &rt->dst; 978 struct fib_result res; 979 980 if (dst_metric_locked(dst, RTAX_MTU)) 981 return; 982 983 if (ipv4_mtu(dst) < mtu) 984 return; 985 986 if (mtu < ip_rt_min_pmtu) 987 mtu = ip_rt_min_pmtu; 988 989 if (rt->rt_pmtu == mtu && 990 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 991 return; 992 993 rcu_read_lock(); 994 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 995 struct fib_nh *nh = &FIB_RES_NH(res); 996 997 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, 998 jiffies + ip_rt_mtu_expires); 999 } 1000 rcu_read_unlock(); 1001 } 1002 1003 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1004 struct sk_buff *skb, u32 mtu) 1005 { 1006 struct rtable *rt = (struct rtable *) dst; 1007 struct flowi4 fl4; 1008 1009 ip_rt_build_flow_key(&fl4, sk, skb); 1010 __ip_rt_update_pmtu(rt, &fl4, mtu); 1011 } 1012 1013 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1014 int oif, u32 mark, u8 protocol, int flow_flags) 1015 { 1016 const struct iphdr *iph = (const struct iphdr *) skb->data; 1017 struct flowi4 fl4; 1018 struct rtable *rt; 1019 1020 if (!mark) 1021 mark = IP4_REPLY_MARK(net, skb->mark); 1022 1023 __build_flow_key(&fl4, NULL, iph, oif, 1024 RT_TOS(iph->tos), protocol, mark, flow_flags); 1025 rt = __ip_route_output_key(net, &fl4); 1026 if (!IS_ERR(rt)) { 1027 __ip_rt_update_pmtu(rt, &fl4, mtu); 1028 ip_rt_put(rt); 1029 } 1030 } 1031 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1032 1033 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1034 { 1035 const struct iphdr *iph = (const struct iphdr *) skb->data; 1036 struct flowi4 fl4; 1037 struct rtable *rt; 1038 1039 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1040 1041 if (!fl4.flowi4_mark) 1042 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1043 1044 rt = __ip_route_output_key(sock_net(sk), &fl4); 1045 if (!IS_ERR(rt)) { 1046 __ip_rt_update_pmtu(rt, &fl4, mtu); 1047 ip_rt_put(rt); 1048 } 1049 } 1050 1051 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1052 { 1053 const struct iphdr *iph = (const struct iphdr *) skb->data; 1054 struct flowi4 fl4; 1055 struct rtable *rt; 1056 struct dst_entry *odst = NULL; 1057 bool new = false; 1058 1059 bh_lock_sock(sk); 1060 1061 if (!ip_sk_accept_pmtu(sk)) 1062 goto out; 1063 1064 odst = sk_dst_get(sk); 1065 1066 if (sock_owned_by_user(sk) || !odst) { 1067 __ipv4_sk_update_pmtu(skb, sk, mtu); 1068 goto out; 1069 } 1070 1071 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1072 1073 rt = (struct rtable *)odst; 1074 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1075 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1076 if (IS_ERR(rt)) 1077 goto out; 1078 1079 new = true; 1080 } 1081 1082 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu); 1083 1084 if (!dst_check(&rt->dst, 0)) { 1085 if (new) 1086 dst_release(&rt->dst); 1087 1088 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1089 if (IS_ERR(rt)) 1090 goto out; 1091 1092 new = true; 1093 } 1094 1095 if (new) 1096 sk_dst_set(sk, &rt->dst); 1097 1098 out: 1099 bh_unlock_sock(sk); 1100 dst_release(odst); 1101 } 1102 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1103 1104 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1105 int oif, u32 mark, u8 protocol, int flow_flags) 1106 { 1107 const struct iphdr *iph = (const struct iphdr *) skb->data; 1108 struct flowi4 fl4; 1109 struct rtable *rt; 1110 1111 __build_flow_key(&fl4, NULL, iph, oif, 1112 RT_TOS(iph->tos), protocol, mark, flow_flags); 1113 rt = __ip_route_output_key(net, &fl4); 1114 if (!IS_ERR(rt)) { 1115 __ip_do_redirect(rt, skb, &fl4, false); 1116 ip_rt_put(rt); 1117 } 1118 } 1119 EXPORT_SYMBOL_GPL(ipv4_redirect); 1120 1121 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1122 { 1123 const struct iphdr *iph = (const struct iphdr *) skb->data; 1124 struct flowi4 fl4; 1125 struct rtable *rt; 1126 1127 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1128 rt = __ip_route_output_key(sock_net(sk), &fl4); 1129 if (!IS_ERR(rt)) { 1130 __ip_do_redirect(rt, skb, &fl4, false); 1131 ip_rt_put(rt); 1132 } 1133 } 1134 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1135 1136 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1137 { 1138 struct rtable *rt = (struct rtable *) dst; 1139 1140 /* All IPV4 dsts are created with ->obsolete set to the value 1141 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1142 * into this function always. 1143 * 1144 * When a PMTU/redirect information update invalidates a route, 1145 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1146 * DST_OBSOLETE_DEAD by dst_free(). 1147 */ 1148 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1149 return NULL; 1150 return dst; 1151 } 1152 1153 static void ipv4_link_failure(struct sk_buff *skb) 1154 { 1155 struct rtable *rt; 1156 1157 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1158 1159 rt = skb_rtable(skb); 1160 if (rt) 1161 dst_set_expires(&rt->dst, 0); 1162 } 1163 1164 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1165 { 1166 pr_debug("%s: %pI4 -> %pI4, %s\n", 1167 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1168 skb->dev ? skb->dev->name : "?"); 1169 kfree_skb(skb); 1170 WARN_ON(1); 1171 return 0; 1172 } 1173 1174 /* 1175 We do not cache source address of outgoing interface, 1176 because it is used only by IP RR, TS and SRR options, 1177 so that it out of fast path. 1178 1179 BTW remember: "addr" is allowed to be not aligned 1180 in IP options! 1181 */ 1182 1183 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1184 { 1185 __be32 src; 1186 1187 if (rt_is_output_route(rt)) 1188 src = ip_hdr(skb)->saddr; 1189 else { 1190 struct fib_result res; 1191 struct flowi4 fl4; 1192 struct iphdr *iph; 1193 1194 iph = ip_hdr(skb); 1195 1196 memset(&fl4, 0, sizeof(fl4)); 1197 fl4.daddr = iph->daddr; 1198 fl4.saddr = iph->saddr; 1199 fl4.flowi4_tos = RT_TOS(iph->tos); 1200 fl4.flowi4_oif = rt->dst.dev->ifindex; 1201 fl4.flowi4_iif = skb->dev->ifindex; 1202 fl4.flowi4_mark = skb->mark; 1203 1204 rcu_read_lock(); 1205 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1206 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1207 else 1208 src = inet_select_addr(rt->dst.dev, 1209 rt_nexthop(rt, iph->daddr), 1210 RT_SCOPE_UNIVERSE); 1211 rcu_read_unlock(); 1212 } 1213 memcpy(addr, &src, 4); 1214 } 1215 1216 #ifdef CONFIG_IP_ROUTE_CLASSID 1217 static void set_class_tag(struct rtable *rt, u32 tag) 1218 { 1219 if (!(rt->dst.tclassid & 0xFFFF)) 1220 rt->dst.tclassid |= tag & 0xFFFF; 1221 if (!(rt->dst.tclassid & 0xFFFF0000)) 1222 rt->dst.tclassid |= tag & 0xFFFF0000; 1223 } 1224 #endif 1225 1226 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1227 { 1228 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); 1229 1230 if (advmss == 0) { 1231 advmss = max_t(unsigned int, dst->dev->mtu - 40, 1232 ip_rt_min_advmss); 1233 if (advmss > 65535 - 40) 1234 advmss = 65535 - 40; 1235 } 1236 return advmss; 1237 } 1238 1239 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1240 { 1241 const struct rtable *rt = (const struct rtable *) dst; 1242 unsigned int mtu = rt->rt_pmtu; 1243 1244 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1245 mtu = dst_metric_raw(dst, RTAX_MTU); 1246 1247 if (mtu) 1248 return mtu; 1249 1250 mtu = dst->dev->mtu; 1251 1252 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { 1253 if (rt->rt_uses_gateway && mtu > 576) 1254 mtu = 576; 1255 } 1256 1257 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1258 1259 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1260 } 1261 1262 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1263 { 1264 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1265 struct fib_nh_exception *fnhe; 1266 u32 hval; 1267 1268 if (!hash) 1269 return NULL; 1270 1271 hval = fnhe_hashfun(daddr); 1272 1273 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1274 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1275 if (fnhe->fnhe_daddr == daddr) 1276 return fnhe; 1277 } 1278 return NULL; 1279 } 1280 1281 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1282 __be32 daddr) 1283 { 1284 bool ret = false; 1285 1286 spin_lock_bh(&fnhe_lock); 1287 1288 if (daddr == fnhe->fnhe_daddr) { 1289 struct rtable __rcu **porig; 1290 struct rtable *orig; 1291 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1292 1293 if (rt_is_input_route(rt)) 1294 porig = &fnhe->fnhe_rth_input; 1295 else 1296 porig = &fnhe->fnhe_rth_output; 1297 orig = rcu_dereference(*porig); 1298 1299 if (fnhe->fnhe_genid != genid) { 1300 fnhe->fnhe_genid = genid; 1301 fnhe->fnhe_gw = 0; 1302 fnhe->fnhe_pmtu = 0; 1303 fnhe->fnhe_expires = 0; 1304 fnhe_flush_routes(fnhe); 1305 orig = NULL; 1306 } 1307 fill_route_from_fnhe(rt, fnhe); 1308 if (!rt->rt_gateway) 1309 rt->rt_gateway = daddr; 1310 1311 if (!(rt->dst.flags & DST_NOCACHE)) { 1312 rcu_assign_pointer(*porig, rt); 1313 if (orig) 1314 rt_free(orig); 1315 ret = true; 1316 } 1317 1318 fnhe->fnhe_stamp = jiffies; 1319 } 1320 spin_unlock_bh(&fnhe_lock); 1321 1322 return ret; 1323 } 1324 1325 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1326 { 1327 struct rtable *orig, *prev, **p; 1328 bool ret = true; 1329 1330 if (rt_is_input_route(rt)) { 1331 p = (struct rtable **)&nh->nh_rth_input; 1332 } else { 1333 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1334 } 1335 orig = *p; 1336 1337 prev = cmpxchg(p, orig, rt); 1338 if (prev == orig) { 1339 if (orig) 1340 rt_free(orig); 1341 } else 1342 ret = false; 1343 1344 return ret; 1345 } 1346 1347 struct uncached_list { 1348 spinlock_t lock; 1349 struct list_head head; 1350 }; 1351 1352 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1353 1354 static void rt_add_uncached_list(struct rtable *rt) 1355 { 1356 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1357 1358 rt->rt_uncached_list = ul; 1359 1360 spin_lock_bh(&ul->lock); 1361 list_add_tail(&rt->rt_uncached, &ul->head); 1362 spin_unlock_bh(&ul->lock); 1363 } 1364 1365 static void ipv4_dst_destroy(struct dst_entry *dst) 1366 { 1367 struct rtable *rt = (struct rtable *) dst; 1368 1369 if (!list_empty(&rt->rt_uncached)) { 1370 struct uncached_list *ul = rt->rt_uncached_list; 1371 1372 spin_lock_bh(&ul->lock); 1373 list_del(&rt->rt_uncached); 1374 spin_unlock_bh(&ul->lock); 1375 } 1376 } 1377 1378 void rt_flush_dev(struct net_device *dev) 1379 { 1380 struct net *net = dev_net(dev); 1381 struct rtable *rt; 1382 int cpu; 1383 1384 for_each_possible_cpu(cpu) { 1385 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1386 1387 spin_lock_bh(&ul->lock); 1388 list_for_each_entry(rt, &ul->head, rt_uncached) { 1389 if (rt->dst.dev != dev) 1390 continue; 1391 rt->dst.dev = net->loopback_dev; 1392 dev_hold(rt->dst.dev); 1393 dev_put(dev); 1394 } 1395 spin_unlock_bh(&ul->lock); 1396 } 1397 } 1398 1399 static bool rt_cache_valid(const struct rtable *rt) 1400 { 1401 return rt && 1402 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1403 !rt_is_expired(rt); 1404 } 1405 1406 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1407 const struct fib_result *res, 1408 struct fib_nh_exception *fnhe, 1409 struct fib_info *fi, u16 type, u32 itag) 1410 { 1411 bool cached = false; 1412 1413 if (fi) { 1414 struct fib_nh *nh = &FIB_RES_NH(*res); 1415 1416 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1417 rt->rt_gateway = nh->nh_gw; 1418 rt->rt_uses_gateway = 1; 1419 } 1420 dst_init_metrics(&rt->dst, fi->fib_metrics, true); 1421 #ifdef CONFIG_IP_ROUTE_CLASSID 1422 rt->dst.tclassid = nh->nh_tclassid; 1423 #endif 1424 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1425 if (unlikely(fnhe)) 1426 cached = rt_bind_exception(rt, fnhe, daddr); 1427 else if (!(rt->dst.flags & DST_NOCACHE)) 1428 cached = rt_cache_route(nh, rt); 1429 if (unlikely(!cached)) { 1430 /* Routes we intend to cache in nexthop exception or 1431 * FIB nexthop have the DST_NOCACHE bit clear. 1432 * However, if we are unsuccessful at storing this 1433 * route into the cache we really need to set it. 1434 */ 1435 rt->dst.flags |= DST_NOCACHE; 1436 if (!rt->rt_gateway) 1437 rt->rt_gateway = daddr; 1438 rt_add_uncached_list(rt); 1439 } 1440 } else 1441 rt_add_uncached_list(rt); 1442 1443 #ifdef CONFIG_IP_ROUTE_CLASSID 1444 #ifdef CONFIG_IP_MULTIPLE_TABLES 1445 set_class_tag(rt, res->tclassid); 1446 #endif 1447 set_class_tag(rt, itag); 1448 #endif 1449 } 1450 1451 struct rtable *rt_dst_alloc(struct net_device *dev, 1452 unsigned int flags, u16 type, 1453 bool nopolicy, bool noxfrm, bool will_cache) 1454 { 1455 struct rtable *rt; 1456 1457 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1458 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) | 1459 (nopolicy ? DST_NOPOLICY : 0) | 1460 (noxfrm ? DST_NOXFRM : 0)); 1461 1462 if (rt) { 1463 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1464 rt->rt_flags = flags; 1465 rt->rt_type = type; 1466 rt->rt_is_input = 0; 1467 rt->rt_iif = 0; 1468 rt->rt_pmtu = 0; 1469 rt->rt_gateway = 0; 1470 rt->rt_uses_gateway = 0; 1471 rt->rt_table_id = 0; 1472 INIT_LIST_HEAD(&rt->rt_uncached); 1473 1474 rt->dst.output = ip_output; 1475 if (flags & RTCF_LOCAL) 1476 rt->dst.input = ip_local_deliver; 1477 } 1478 1479 return rt; 1480 } 1481 EXPORT_SYMBOL(rt_dst_alloc); 1482 1483 /* called in rcu_read_lock() section */ 1484 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1485 u8 tos, struct net_device *dev, int our) 1486 { 1487 struct rtable *rth; 1488 struct in_device *in_dev = __in_dev_get_rcu(dev); 1489 unsigned int flags = RTCF_MULTICAST; 1490 u32 itag = 0; 1491 int err; 1492 1493 /* Primary sanity checks. */ 1494 1495 if (!in_dev) 1496 return -EINVAL; 1497 1498 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1499 skb->protocol != htons(ETH_P_IP)) 1500 goto e_inval; 1501 1502 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1503 goto e_inval; 1504 1505 if (ipv4_is_zeronet(saddr)) { 1506 if (!ipv4_is_local_multicast(daddr)) 1507 goto e_inval; 1508 } else { 1509 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1510 in_dev, &itag); 1511 if (err < 0) 1512 goto e_err; 1513 } 1514 if (our) 1515 flags |= RTCF_LOCAL; 1516 1517 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1518 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1519 if (!rth) 1520 goto e_nobufs; 1521 1522 #ifdef CONFIG_IP_ROUTE_CLASSID 1523 rth->dst.tclassid = itag; 1524 #endif 1525 rth->dst.output = ip_rt_bug; 1526 rth->rt_is_input= 1; 1527 1528 #ifdef CONFIG_IP_MROUTE 1529 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1530 rth->dst.input = ip_mr_input; 1531 #endif 1532 RT_CACHE_STAT_INC(in_slow_mc); 1533 1534 skb_dst_set(skb, &rth->dst); 1535 return 0; 1536 1537 e_nobufs: 1538 return -ENOBUFS; 1539 e_inval: 1540 return -EINVAL; 1541 e_err: 1542 return err; 1543 } 1544 1545 1546 static void ip_handle_martian_source(struct net_device *dev, 1547 struct in_device *in_dev, 1548 struct sk_buff *skb, 1549 __be32 daddr, 1550 __be32 saddr) 1551 { 1552 RT_CACHE_STAT_INC(in_martian_src); 1553 #ifdef CONFIG_IP_ROUTE_VERBOSE 1554 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1555 /* 1556 * RFC1812 recommendation, if source is martian, 1557 * the only hint is MAC header. 1558 */ 1559 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1560 &daddr, &saddr, dev->name); 1561 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1562 print_hex_dump(KERN_WARNING, "ll header: ", 1563 DUMP_PREFIX_OFFSET, 16, 1, 1564 skb_mac_header(skb), 1565 dev->hard_header_len, true); 1566 } 1567 } 1568 #endif 1569 } 1570 1571 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1572 { 1573 struct fnhe_hash_bucket *hash; 1574 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1575 u32 hval = fnhe_hashfun(daddr); 1576 1577 spin_lock_bh(&fnhe_lock); 1578 1579 hash = rcu_dereference_protected(nh->nh_exceptions, 1580 lockdep_is_held(&fnhe_lock)); 1581 hash += hval; 1582 1583 fnhe_p = &hash->chain; 1584 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1585 while (fnhe) { 1586 if (fnhe->fnhe_daddr == daddr) { 1587 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1588 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1589 fnhe_flush_routes(fnhe); 1590 kfree_rcu(fnhe, rcu); 1591 break; 1592 } 1593 fnhe_p = &fnhe->fnhe_next; 1594 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1595 lockdep_is_held(&fnhe_lock)); 1596 } 1597 1598 spin_unlock_bh(&fnhe_lock); 1599 } 1600 1601 /* called in rcu_read_lock() section */ 1602 static int __mkroute_input(struct sk_buff *skb, 1603 const struct fib_result *res, 1604 struct in_device *in_dev, 1605 __be32 daddr, __be32 saddr, u32 tos) 1606 { 1607 struct fib_nh_exception *fnhe; 1608 struct rtable *rth; 1609 int err; 1610 struct in_device *out_dev; 1611 bool do_cache; 1612 u32 itag = 0; 1613 1614 /* get a working reference to the output device */ 1615 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1616 if (!out_dev) { 1617 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1618 return -EINVAL; 1619 } 1620 1621 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1622 in_dev->dev, in_dev, &itag); 1623 if (err < 0) { 1624 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1625 saddr); 1626 1627 goto cleanup; 1628 } 1629 1630 do_cache = res->fi && !itag; 1631 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1632 skb->protocol == htons(ETH_P_IP) && 1633 (IN_DEV_SHARED_MEDIA(out_dev) || 1634 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1635 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1636 1637 if (skb->protocol != htons(ETH_P_IP)) { 1638 /* Not IP (i.e. ARP). Do not create route, if it is 1639 * invalid for proxy arp. DNAT routes are always valid. 1640 * 1641 * Proxy arp feature have been extended to allow, ARP 1642 * replies back to the same interface, to support 1643 * Private VLAN switch technologies. See arp.c. 1644 */ 1645 if (out_dev == in_dev && 1646 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1647 err = -EINVAL; 1648 goto cleanup; 1649 } 1650 } 1651 1652 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1653 if (do_cache) { 1654 if (fnhe) { 1655 rth = rcu_dereference(fnhe->fnhe_rth_input); 1656 if (rth && rth->dst.expires && 1657 time_after(jiffies, rth->dst.expires)) { 1658 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1659 fnhe = NULL; 1660 } else { 1661 goto rt_cache; 1662 } 1663 } 1664 1665 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1666 1667 rt_cache: 1668 if (rt_cache_valid(rth)) { 1669 skb_dst_set_noref(skb, &rth->dst); 1670 goto out; 1671 } 1672 } 1673 1674 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1675 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1676 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1677 if (!rth) { 1678 err = -ENOBUFS; 1679 goto cleanup; 1680 } 1681 1682 rth->rt_is_input = 1; 1683 if (res->table) 1684 rth->rt_table_id = res->table->tb_id; 1685 RT_CACHE_STAT_INC(in_slow_tot); 1686 1687 rth->dst.input = ip_forward; 1688 1689 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag); 1690 if (lwtunnel_output_redirect(rth->dst.lwtstate)) { 1691 rth->dst.lwtstate->orig_output = rth->dst.output; 1692 rth->dst.output = lwtunnel_output; 1693 } 1694 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 1695 rth->dst.lwtstate->orig_input = rth->dst.input; 1696 rth->dst.input = lwtunnel_input; 1697 } 1698 skb_dst_set(skb, &rth->dst); 1699 out: 1700 err = 0; 1701 cleanup: 1702 return err; 1703 } 1704 1705 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1706 1707 /* To make ICMP packets follow the right flow, the multipath hash is 1708 * calculated from the inner IP addresses in reverse order. 1709 */ 1710 static int ip_multipath_icmp_hash(struct sk_buff *skb) 1711 { 1712 const struct iphdr *outer_iph = ip_hdr(skb); 1713 struct icmphdr _icmph; 1714 const struct icmphdr *icmph; 1715 struct iphdr _inner_iph; 1716 const struct iphdr *inner_iph; 1717 1718 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1719 goto standard_hash; 1720 1721 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1722 &_icmph); 1723 if (!icmph) 1724 goto standard_hash; 1725 1726 if (icmph->type != ICMP_DEST_UNREACH && 1727 icmph->type != ICMP_REDIRECT && 1728 icmph->type != ICMP_TIME_EXCEEDED && 1729 icmph->type != ICMP_PARAMETERPROB) { 1730 goto standard_hash; 1731 } 1732 1733 inner_iph = skb_header_pointer(skb, 1734 outer_iph->ihl * 4 + sizeof(_icmph), 1735 sizeof(_inner_iph), &_inner_iph); 1736 if (!inner_iph) 1737 goto standard_hash; 1738 1739 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr); 1740 1741 standard_hash: 1742 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr); 1743 } 1744 1745 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1746 1747 static int ip_mkroute_input(struct sk_buff *skb, 1748 struct fib_result *res, 1749 const struct flowi4 *fl4, 1750 struct in_device *in_dev, 1751 __be32 daddr, __be32 saddr, u32 tos) 1752 { 1753 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1754 if (res->fi && res->fi->fib_nhs > 1) { 1755 int h; 1756 1757 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP)) 1758 h = ip_multipath_icmp_hash(skb); 1759 else 1760 h = fib_multipath_hash(saddr, daddr); 1761 fib_select_multipath(res, h); 1762 } 1763 #endif 1764 1765 /* create a routing cache entry */ 1766 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1767 } 1768 1769 /* 1770 * NOTE. We drop all the packets that has local source 1771 * addresses, because every properly looped back packet 1772 * must have correct destination already attached by output routine. 1773 * 1774 * Such approach solves two big problems: 1775 * 1. Not simplex devices are handled properly. 1776 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1777 * called with rcu_read_lock() 1778 */ 1779 1780 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1781 u8 tos, struct net_device *dev) 1782 { 1783 struct fib_result res; 1784 struct in_device *in_dev = __in_dev_get_rcu(dev); 1785 struct ip_tunnel_info *tun_info; 1786 struct flowi4 fl4; 1787 unsigned int flags = 0; 1788 u32 itag = 0; 1789 struct rtable *rth; 1790 int err = -EINVAL; 1791 struct net *net = dev_net(dev); 1792 bool do_cache; 1793 1794 /* IP on this device is disabled. */ 1795 1796 if (!in_dev) 1797 goto out; 1798 1799 /* Check for the most weird martians, which can be not detected 1800 by fib_lookup. 1801 */ 1802 1803 tun_info = skb_tunnel_info(skb); 1804 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1805 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1806 else 1807 fl4.flowi4_tun_key.tun_id = 0; 1808 skb_dst_drop(skb); 1809 1810 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1811 goto martian_source; 1812 1813 res.fi = NULL; 1814 res.table = NULL; 1815 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1816 goto brd_input; 1817 1818 /* Accept zero addresses only to limited broadcast; 1819 * I even do not know to fix it or not. Waiting for complains :-) 1820 */ 1821 if (ipv4_is_zeronet(saddr)) 1822 goto martian_source; 1823 1824 if (ipv4_is_zeronet(daddr)) 1825 goto martian_destination; 1826 1827 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1828 * and call it once if daddr or/and saddr are loopback addresses 1829 */ 1830 if (ipv4_is_loopback(daddr)) { 1831 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1832 goto martian_destination; 1833 } else if (ipv4_is_loopback(saddr)) { 1834 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1835 goto martian_source; 1836 } 1837 1838 /* 1839 * Now we are ready to route packet. 1840 */ 1841 fl4.flowi4_oif = 0; 1842 fl4.flowi4_iif = dev->ifindex; 1843 fl4.flowi4_mark = skb->mark; 1844 fl4.flowi4_tos = tos; 1845 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1846 fl4.flowi4_flags = 0; 1847 fl4.daddr = daddr; 1848 fl4.saddr = saddr; 1849 err = fib_lookup(net, &fl4, &res, 0); 1850 if (err != 0) { 1851 if (!IN_DEV_FORWARD(in_dev)) 1852 err = -EHOSTUNREACH; 1853 goto no_route; 1854 } 1855 1856 if (res.type == RTN_BROADCAST) 1857 goto brd_input; 1858 1859 if (res.type == RTN_LOCAL) { 1860 err = fib_validate_source(skb, saddr, daddr, tos, 1861 0, dev, in_dev, &itag); 1862 if (err < 0) 1863 goto martian_source; 1864 goto local_input; 1865 } 1866 1867 if (!IN_DEV_FORWARD(in_dev)) { 1868 err = -EHOSTUNREACH; 1869 goto no_route; 1870 } 1871 if (res.type != RTN_UNICAST) 1872 goto martian_destination; 1873 1874 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); 1875 out: return err; 1876 1877 brd_input: 1878 if (skb->protocol != htons(ETH_P_IP)) 1879 goto e_inval; 1880 1881 if (!ipv4_is_zeronet(saddr)) { 1882 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1883 in_dev, &itag); 1884 if (err < 0) 1885 goto martian_source; 1886 } 1887 flags |= RTCF_BROADCAST; 1888 res.type = RTN_BROADCAST; 1889 RT_CACHE_STAT_INC(in_brd); 1890 1891 local_input: 1892 do_cache = false; 1893 if (res.fi) { 1894 if (!itag) { 1895 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input); 1896 if (rt_cache_valid(rth)) { 1897 skb_dst_set_noref(skb, &rth->dst); 1898 err = 0; 1899 goto out; 1900 } 1901 do_cache = true; 1902 } 1903 } 1904 1905 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type, 1906 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 1907 if (!rth) 1908 goto e_nobufs; 1909 1910 rth->dst.output= ip_rt_bug; 1911 #ifdef CONFIG_IP_ROUTE_CLASSID 1912 rth->dst.tclassid = itag; 1913 #endif 1914 rth->rt_is_input = 1; 1915 if (res.table) 1916 rth->rt_table_id = res.table->tb_id; 1917 1918 RT_CACHE_STAT_INC(in_slow_tot); 1919 if (res.type == RTN_UNREACHABLE) { 1920 rth->dst.input= ip_error; 1921 rth->dst.error= -err; 1922 rth->rt_flags &= ~RTCF_LOCAL; 1923 } 1924 if (do_cache) { 1925 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) { 1926 rth->dst.flags |= DST_NOCACHE; 1927 rt_add_uncached_list(rth); 1928 } 1929 } 1930 skb_dst_set(skb, &rth->dst); 1931 err = 0; 1932 goto out; 1933 1934 no_route: 1935 RT_CACHE_STAT_INC(in_no_route); 1936 res.type = RTN_UNREACHABLE; 1937 res.fi = NULL; 1938 res.table = NULL; 1939 goto local_input; 1940 1941 /* 1942 * Do not cache martian addresses: they should be logged (RFC1812) 1943 */ 1944 martian_destination: 1945 RT_CACHE_STAT_INC(in_martian_dst); 1946 #ifdef CONFIG_IP_ROUTE_VERBOSE 1947 if (IN_DEV_LOG_MARTIANS(in_dev)) 1948 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 1949 &daddr, &saddr, dev->name); 1950 #endif 1951 1952 e_inval: 1953 err = -EINVAL; 1954 goto out; 1955 1956 e_nobufs: 1957 err = -ENOBUFS; 1958 goto out; 1959 1960 martian_source: 1961 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 1962 goto out; 1963 } 1964 1965 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1966 u8 tos, struct net_device *dev) 1967 { 1968 int res; 1969 1970 rcu_read_lock(); 1971 1972 /* Multicast recognition logic is moved from route cache to here. 1973 The problem was that too many Ethernet cards have broken/missing 1974 hardware multicast filters :-( As result the host on multicasting 1975 network acquires a lot of useless route cache entries, sort of 1976 SDR messages from all the world. Now we try to get rid of them. 1977 Really, provided software IP multicast filter is organized 1978 reasonably (at least, hashed), it does not result in a slowdown 1979 comparing with route cache reject entries. 1980 Note, that multicast routers are not affected, because 1981 route cache entry is created eventually. 1982 */ 1983 if (ipv4_is_multicast(daddr)) { 1984 struct in_device *in_dev = __in_dev_get_rcu(dev); 1985 1986 if (in_dev) { 1987 int our = ip_check_mc_rcu(in_dev, daddr, saddr, 1988 ip_hdr(skb)->protocol); 1989 if (our 1990 #ifdef CONFIG_IP_MROUTE 1991 || 1992 (!ipv4_is_local_multicast(daddr) && 1993 IN_DEV_MFORWARD(in_dev)) 1994 #endif 1995 ) { 1996 int res = ip_route_input_mc(skb, daddr, saddr, 1997 tos, dev, our); 1998 rcu_read_unlock(); 1999 return res; 2000 } 2001 } 2002 rcu_read_unlock(); 2003 return -EINVAL; 2004 } 2005 res = ip_route_input_slow(skb, daddr, saddr, tos, dev); 2006 rcu_read_unlock(); 2007 return res; 2008 } 2009 EXPORT_SYMBOL(ip_route_input_noref); 2010 2011 /* called with rcu_read_lock() */ 2012 static struct rtable *__mkroute_output(const struct fib_result *res, 2013 const struct flowi4 *fl4, int orig_oif, 2014 struct net_device *dev_out, 2015 unsigned int flags) 2016 { 2017 struct fib_info *fi = res->fi; 2018 struct fib_nh_exception *fnhe; 2019 struct in_device *in_dev; 2020 u16 type = res->type; 2021 struct rtable *rth; 2022 bool do_cache; 2023 2024 in_dev = __in_dev_get_rcu(dev_out); 2025 if (!in_dev) 2026 return ERR_PTR(-EINVAL); 2027 2028 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2029 if (ipv4_is_loopback(fl4->saddr) && 2030 !(dev_out->flags & IFF_LOOPBACK) && 2031 !netif_is_l3_master(dev_out)) 2032 return ERR_PTR(-EINVAL); 2033 2034 if (ipv4_is_lbcast(fl4->daddr)) 2035 type = RTN_BROADCAST; 2036 else if (ipv4_is_multicast(fl4->daddr)) 2037 type = RTN_MULTICAST; 2038 else if (ipv4_is_zeronet(fl4->daddr)) 2039 return ERR_PTR(-EINVAL); 2040 2041 if (dev_out->flags & IFF_LOOPBACK) 2042 flags |= RTCF_LOCAL; 2043 2044 do_cache = true; 2045 if (type == RTN_BROADCAST) { 2046 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2047 fi = NULL; 2048 } else if (type == RTN_MULTICAST) { 2049 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2050 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2051 fl4->flowi4_proto)) 2052 flags &= ~RTCF_LOCAL; 2053 else 2054 do_cache = false; 2055 /* If multicast route do not exist use 2056 * default one, but do not gateway in this case. 2057 * Yes, it is hack. 2058 */ 2059 if (fi && res->prefixlen < 4) 2060 fi = NULL; 2061 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2062 (orig_oif != dev_out->ifindex)) { 2063 /* For local routes that require a particular output interface 2064 * we do not want to cache the result. Caching the result 2065 * causes incorrect behaviour when there are multiple source 2066 * addresses on the interface, the end result being that if the 2067 * intended recipient is waiting on that interface for the 2068 * packet he won't receive it because it will be delivered on 2069 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2070 * be set to the loopback interface as well. 2071 */ 2072 fi = NULL; 2073 } 2074 2075 fnhe = NULL; 2076 do_cache &= fi != NULL; 2077 if (do_cache) { 2078 struct rtable __rcu **prth; 2079 struct fib_nh *nh = &FIB_RES_NH(*res); 2080 2081 fnhe = find_exception(nh, fl4->daddr); 2082 if (fnhe) { 2083 prth = &fnhe->fnhe_rth_output; 2084 rth = rcu_dereference(*prth); 2085 if (rth && rth->dst.expires && 2086 time_after(jiffies, rth->dst.expires)) { 2087 ip_del_fnhe(nh, fl4->daddr); 2088 fnhe = NULL; 2089 } else { 2090 goto rt_cache; 2091 } 2092 } 2093 2094 if (unlikely(fl4->flowi4_flags & 2095 FLOWI_FLAG_KNOWN_NH && 2096 !(nh->nh_gw && 2097 nh->nh_scope == RT_SCOPE_LINK))) { 2098 do_cache = false; 2099 goto add; 2100 } 2101 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2102 rth = rcu_dereference(*prth); 2103 2104 rt_cache: 2105 if (rt_cache_valid(rth)) { 2106 dst_hold(&rth->dst); 2107 return rth; 2108 } 2109 } 2110 2111 add: 2112 rth = rt_dst_alloc(dev_out, flags, type, 2113 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2114 IN_DEV_CONF_GET(in_dev, NOXFRM), 2115 do_cache); 2116 if (!rth) 2117 return ERR_PTR(-ENOBUFS); 2118 2119 rth->rt_iif = orig_oif ? : 0; 2120 if (res->table) 2121 rth->rt_table_id = res->table->tb_id; 2122 2123 RT_CACHE_STAT_INC(out_slow_tot); 2124 2125 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2126 if (flags & RTCF_LOCAL && 2127 !(dev_out->flags & IFF_LOOPBACK)) { 2128 rth->dst.output = ip_mc_output; 2129 RT_CACHE_STAT_INC(out_slow_mc); 2130 } 2131 #ifdef CONFIG_IP_MROUTE 2132 if (type == RTN_MULTICAST) { 2133 if (IN_DEV_MFORWARD(in_dev) && 2134 !ipv4_is_local_multicast(fl4->daddr)) { 2135 rth->dst.input = ip_mr_input; 2136 rth->dst.output = ip_mc_output; 2137 } 2138 } 2139 #endif 2140 } 2141 2142 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0); 2143 if (lwtunnel_output_redirect(rth->dst.lwtstate)) 2144 rth->dst.output = lwtunnel_output; 2145 2146 return rth; 2147 } 2148 2149 /* 2150 * Major route resolver routine. 2151 */ 2152 2153 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2154 int mp_hash) 2155 { 2156 struct net_device *dev_out = NULL; 2157 __u8 tos = RT_FL_TOS(fl4); 2158 unsigned int flags = 0; 2159 struct fib_result res; 2160 struct rtable *rth; 2161 int orig_oif; 2162 int err = -ENETUNREACH; 2163 2164 res.tclassid = 0; 2165 res.fi = NULL; 2166 res.table = NULL; 2167 2168 orig_oif = fl4->flowi4_oif; 2169 2170 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2171 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2172 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2173 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2174 2175 rcu_read_lock(); 2176 if (fl4->saddr) { 2177 rth = ERR_PTR(-EINVAL); 2178 if (ipv4_is_multicast(fl4->saddr) || 2179 ipv4_is_lbcast(fl4->saddr) || 2180 ipv4_is_zeronet(fl4->saddr)) 2181 goto out; 2182 2183 /* I removed check for oif == dev_out->oif here. 2184 It was wrong for two reasons: 2185 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2186 is assigned to multiple interfaces. 2187 2. Moreover, we are allowed to send packets with saddr 2188 of another iface. --ANK 2189 */ 2190 2191 if (fl4->flowi4_oif == 0 && 2192 (ipv4_is_multicast(fl4->daddr) || 2193 ipv4_is_lbcast(fl4->daddr))) { 2194 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2195 dev_out = __ip_dev_find(net, fl4->saddr, false); 2196 if (!dev_out) 2197 goto out; 2198 2199 /* Special hack: user can direct multicasts 2200 and limited broadcast via necessary interface 2201 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2202 This hack is not just for fun, it allows 2203 vic,vat and friends to work. 2204 They bind socket to loopback, set ttl to zero 2205 and expect that it will work. 2206 From the viewpoint of routing cache they are broken, 2207 because we are not allowed to build multicast path 2208 with loopback source addr (look, routing cache 2209 cannot know, that ttl is zero, so that packet 2210 will not leave this host and route is valid). 2211 Luckily, this hack is good workaround. 2212 */ 2213 2214 fl4->flowi4_oif = dev_out->ifindex; 2215 goto make_route; 2216 } 2217 2218 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2219 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2220 if (!__ip_dev_find(net, fl4->saddr, false)) 2221 goto out; 2222 } 2223 } 2224 2225 2226 if (fl4->flowi4_oif) { 2227 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2228 rth = ERR_PTR(-ENODEV); 2229 if (!dev_out) 2230 goto out; 2231 2232 /* RACE: Check return value of inet_select_addr instead. */ 2233 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2234 rth = ERR_PTR(-ENETUNREACH); 2235 goto out; 2236 } 2237 if (ipv4_is_local_multicast(fl4->daddr) || 2238 ipv4_is_lbcast(fl4->daddr) || 2239 fl4->flowi4_proto == IPPROTO_IGMP) { 2240 if (!fl4->saddr) 2241 fl4->saddr = inet_select_addr(dev_out, 0, 2242 RT_SCOPE_LINK); 2243 goto make_route; 2244 } 2245 if (!fl4->saddr) { 2246 if (ipv4_is_multicast(fl4->daddr)) 2247 fl4->saddr = inet_select_addr(dev_out, 0, 2248 fl4->flowi4_scope); 2249 else if (!fl4->daddr) 2250 fl4->saddr = inet_select_addr(dev_out, 0, 2251 RT_SCOPE_HOST); 2252 } 2253 } 2254 2255 if (!fl4->daddr) { 2256 fl4->daddr = fl4->saddr; 2257 if (!fl4->daddr) 2258 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2259 dev_out = net->loopback_dev; 2260 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2261 res.type = RTN_LOCAL; 2262 flags |= RTCF_LOCAL; 2263 goto make_route; 2264 } 2265 2266 err = fib_lookup(net, fl4, &res, 0); 2267 if (err) { 2268 res.fi = NULL; 2269 res.table = NULL; 2270 if (fl4->flowi4_oif && 2271 !netif_index_is_l3_master(net, fl4->flowi4_oif)) { 2272 /* Apparently, routing tables are wrong. Assume, 2273 that the destination is on link. 2274 2275 WHY? DW. 2276 Because we are allowed to send to iface 2277 even if it has NO routes and NO assigned 2278 addresses. When oif is specified, routing 2279 tables are looked up with only one purpose: 2280 to catch if destination is gatewayed, rather than 2281 direct. Moreover, if MSG_DONTROUTE is set, 2282 we send packet, ignoring both routing tables 2283 and ifaddr state. --ANK 2284 2285 2286 We could make it even if oif is unknown, 2287 likely IPv6, but we do not. 2288 */ 2289 2290 if (fl4->saddr == 0) 2291 fl4->saddr = inet_select_addr(dev_out, 0, 2292 RT_SCOPE_LINK); 2293 res.type = RTN_UNICAST; 2294 goto make_route; 2295 } 2296 rth = ERR_PTR(err); 2297 goto out; 2298 } 2299 2300 if (res.type == RTN_LOCAL) { 2301 if (!fl4->saddr) { 2302 if (res.fi->fib_prefsrc) 2303 fl4->saddr = res.fi->fib_prefsrc; 2304 else 2305 fl4->saddr = fl4->daddr; 2306 } 2307 2308 /* L3 master device is the loopback for that domain */ 2309 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev; 2310 fl4->flowi4_oif = dev_out->ifindex; 2311 flags |= RTCF_LOCAL; 2312 goto make_route; 2313 } 2314 2315 fib_select_path(net, &res, fl4, mp_hash); 2316 2317 dev_out = FIB_RES_DEV(res); 2318 fl4->flowi4_oif = dev_out->ifindex; 2319 2320 2321 make_route: 2322 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags); 2323 2324 out: 2325 rcu_read_unlock(); 2326 return rth; 2327 } 2328 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash); 2329 2330 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2331 { 2332 return NULL; 2333 } 2334 2335 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2336 { 2337 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2338 2339 return mtu ? : dst->dev->mtu; 2340 } 2341 2342 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2343 struct sk_buff *skb, u32 mtu) 2344 { 2345 } 2346 2347 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2348 struct sk_buff *skb) 2349 { 2350 } 2351 2352 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2353 unsigned long old) 2354 { 2355 return NULL; 2356 } 2357 2358 static struct dst_ops ipv4_dst_blackhole_ops = { 2359 .family = AF_INET, 2360 .check = ipv4_blackhole_dst_check, 2361 .mtu = ipv4_blackhole_mtu, 2362 .default_advmss = ipv4_default_advmss, 2363 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2364 .redirect = ipv4_rt_blackhole_redirect, 2365 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2366 .neigh_lookup = ipv4_neigh_lookup, 2367 }; 2368 2369 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2370 { 2371 struct rtable *ort = (struct rtable *) dst_orig; 2372 struct rtable *rt; 2373 2374 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0); 2375 if (rt) { 2376 struct dst_entry *new = &rt->dst; 2377 2378 new->__use = 1; 2379 new->input = dst_discard; 2380 new->output = dst_discard_out; 2381 2382 new->dev = ort->dst.dev; 2383 if (new->dev) 2384 dev_hold(new->dev); 2385 2386 rt->rt_is_input = ort->rt_is_input; 2387 rt->rt_iif = ort->rt_iif; 2388 rt->rt_pmtu = ort->rt_pmtu; 2389 2390 rt->rt_genid = rt_genid_ipv4(net); 2391 rt->rt_flags = ort->rt_flags; 2392 rt->rt_type = ort->rt_type; 2393 rt->rt_gateway = ort->rt_gateway; 2394 rt->rt_uses_gateway = ort->rt_uses_gateway; 2395 2396 INIT_LIST_HEAD(&rt->rt_uncached); 2397 dst_free(new); 2398 } 2399 2400 dst_release(dst_orig); 2401 2402 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2403 } 2404 2405 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2406 const struct sock *sk) 2407 { 2408 struct rtable *rt = __ip_route_output_key(net, flp4); 2409 2410 if (IS_ERR(rt)) 2411 return rt; 2412 2413 if (flp4->flowi4_proto) 2414 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2415 flowi4_to_flowi(flp4), 2416 sk, 0); 2417 2418 return rt; 2419 } 2420 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2421 2422 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2423 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2424 u32 seq, int event, int nowait, unsigned int flags) 2425 { 2426 struct rtable *rt = skb_rtable(skb); 2427 struct rtmsg *r; 2428 struct nlmsghdr *nlh; 2429 unsigned long expires = 0; 2430 u32 error; 2431 u32 metrics[RTAX_MAX]; 2432 2433 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags); 2434 if (!nlh) 2435 return -EMSGSIZE; 2436 2437 r = nlmsg_data(nlh); 2438 r->rtm_family = AF_INET; 2439 r->rtm_dst_len = 32; 2440 r->rtm_src_len = 0; 2441 r->rtm_tos = fl4->flowi4_tos; 2442 r->rtm_table = table_id; 2443 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2444 goto nla_put_failure; 2445 r->rtm_type = rt->rt_type; 2446 r->rtm_scope = RT_SCOPE_UNIVERSE; 2447 r->rtm_protocol = RTPROT_UNSPEC; 2448 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2449 if (rt->rt_flags & RTCF_NOTIFY) 2450 r->rtm_flags |= RTM_F_NOTIFY; 2451 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2452 r->rtm_flags |= RTCF_DOREDIRECT; 2453 2454 if (nla_put_in_addr(skb, RTA_DST, dst)) 2455 goto nla_put_failure; 2456 if (src) { 2457 r->rtm_src_len = 32; 2458 if (nla_put_in_addr(skb, RTA_SRC, src)) 2459 goto nla_put_failure; 2460 } 2461 if (rt->dst.dev && 2462 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2463 goto nla_put_failure; 2464 #ifdef CONFIG_IP_ROUTE_CLASSID 2465 if (rt->dst.tclassid && 2466 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2467 goto nla_put_failure; 2468 #endif 2469 if (!rt_is_input_route(rt) && 2470 fl4->saddr != src) { 2471 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2472 goto nla_put_failure; 2473 } 2474 if (rt->rt_uses_gateway && 2475 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2476 goto nla_put_failure; 2477 2478 expires = rt->dst.expires; 2479 if (expires) { 2480 unsigned long now = jiffies; 2481 2482 if (time_before(now, expires)) 2483 expires -= now; 2484 else 2485 expires = 0; 2486 } 2487 2488 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2489 if (rt->rt_pmtu && expires) 2490 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2491 if (rtnetlink_put_metrics(skb, metrics) < 0) 2492 goto nla_put_failure; 2493 2494 if (fl4->flowi4_mark && 2495 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2496 goto nla_put_failure; 2497 2498 error = rt->dst.error; 2499 2500 if (rt_is_input_route(rt)) { 2501 #ifdef CONFIG_IP_MROUTE 2502 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2503 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2504 int err = ipmr_get_route(net, skb, 2505 fl4->saddr, fl4->daddr, 2506 r, nowait, portid); 2507 2508 if (err <= 0) { 2509 if (!nowait) { 2510 if (err == 0) 2511 return 0; 2512 goto nla_put_failure; 2513 } else { 2514 if (err == -EMSGSIZE) 2515 goto nla_put_failure; 2516 error = err; 2517 } 2518 } 2519 } else 2520 #endif 2521 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2522 goto nla_put_failure; 2523 } 2524 2525 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2526 goto nla_put_failure; 2527 2528 nlmsg_end(skb, nlh); 2529 return 0; 2530 2531 nla_put_failure: 2532 nlmsg_cancel(skb, nlh); 2533 return -EMSGSIZE; 2534 } 2535 2536 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh) 2537 { 2538 struct net *net = sock_net(in_skb->sk); 2539 struct rtmsg *rtm; 2540 struct nlattr *tb[RTA_MAX+1]; 2541 struct rtable *rt = NULL; 2542 struct flowi4 fl4; 2543 __be32 dst = 0; 2544 __be32 src = 0; 2545 u32 iif; 2546 int err; 2547 int mark; 2548 struct sk_buff *skb; 2549 u32 table_id = RT_TABLE_MAIN; 2550 2551 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 2552 if (err < 0) 2553 goto errout; 2554 2555 rtm = nlmsg_data(nlh); 2556 2557 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2558 if (!skb) { 2559 err = -ENOBUFS; 2560 goto errout; 2561 } 2562 2563 /* Reserve room for dummy headers, this skb can pass 2564 through good chunk of routing engine. 2565 */ 2566 skb_reset_mac_header(skb); 2567 skb_reset_network_header(skb); 2568 2569 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 2570 ip_hdr(skb)->protocol = IPPROTO_ICMP; 2571 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2572 2573 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2574 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2575 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2576 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2577 2578 memset(&fl4, 0, sizeof(fl4)); 2579 fl4.daddr = dst; 2580 fl4.saddr = src; 2581 fl4.flowi4_tos = rtm->rtm_tos; 2582 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2583 fl4.flowi4_mark = mark; 2584 2585 if (iif) { 2586 struct net_device *dev; 2587 2588 dev = __dev_get_by_index(net, iif); 2589 if (!dev) { 2590 err = -ENODEV; 2591 goto errout_free; 2592 } 2593 2594 skb->protocol = htons(ETH_P_IP); 2595 skb->dev = dev; 2596 skb->mark = mark; 2597 local_bh_disable(); 2598 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 2599 local_bh_enable(); 2600 2601 rt = skb_rtable(skb); 2602 if (err == 0 && rt->dst.error) 2603 err = -rt->dst.error; 2604 } else { 2605 rt = ip_route_output_key(net, &fl4); 2606 2607 err = 0; 2608 if (IS_ERR(rt)) 2609 err = PTR_ERR(rt); 2610 } 2611 2612 if (err) 2613 goto errout_free; 2614 2615 skb_dst_set(skb, &rt->dst); 2616 if (rtm->rtm_flags & RTM_F_NOTIFY) 2617 rt->rt_flags |= RTCF_NOTIFY; 2618 2619 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2620 table_id = rt->rt_table_id; 2621 2622 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2623 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2624 RTM_NEWROUTE, 0, 0); 2625 if (err < 0) 2626 goto errout_free; 2627 2628 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2629 errout: 2630 return err; 2631 2632 errout_free: 2633 kfree_skb(skb); 2634 goto errout; 2635 } 2636 2637 void ip_rt_multicast_event(struct in_device *in_dev) 2638 { 2639 rt_cache_flush(dev_net(in_dev->dev)); 2640 } 2641 2642 #ifdef CONFIG_SYSCTL 2643 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2644 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2645 static int ip_rt_gc_elasticity __read_mostly = 8; 2646 2647 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2648 void __user *buffer, 2649 size_t *lenp, loff_t *ppos) 2650 { 2651 struct net *net = (struct net *)__ctl->extra1; 2652 2653 if (write) { 2654 rt_cache_flush(net); 2655 fnhe_genid_bump(net); 2656 return 0; 2657 } 2658 2659 return -EINVAL; 2660 } 2661 2662 static struct ctl_table ipv4_route_table[] = { 2663 { 2664 .procname = "gc_thresh", 2665 .data = &ipv4_dst_ops.gc_thresh, 2666 .maxlen = sizeof(int), 2667 .mode = 0644, 2668 .proc_handler = proc_dointvec, 2669 }, 2670 { 2671 .procname = "max_size", 2672 .data = &ip_rt_max_size, 2673 .maxlen = sizeof(int), 2674 .mode = 0644, 2675 .proc_handler = proc_dointvec, 2676 }, 2677 { 2678 /* Deprecated. Use gc_min_interval_ms */ 2679 2680 .procname = "gc_min_interval", 2681 .data = &ip_rt_gc_min_interval, 2682 .maxlen = sizeof(int), 2683 .mode = 0644, 2684 .proc_handler = proc_dointvec_jiffies, 2685 }, 2686 { 2687 .procname = "gc_min_interval_ms", 2688 .data = &ip_rt_gc_min_interval, 2689 .maxlen = sizeof(int), 2690 .mode = 0644, 2691 .proc_handler = proc_dointvec_ms_jiffies, 2692 }, 2693 { 2694 .procname = "gc_timeout", 2695 .data = &ip_rt_gc_timeout, 2696 .maxlen = sizeof(int), 2697 .mode = 0644, 2698 .proc_handler = proc_dointvec_jiffies, 2699 }, 2700 { 2701 .procname = "gc_interval", 2702 .data = &ip_rt_gc_interval, 2703 .maxlen = sizeof(int), 2704 .mode = 0644, 2705 .proc_handler = proc_dointvec_jiffies, 2706 }, 2707 { 2708 .procname = "redirect_load", 2709 .data = &ip_rt_redirect_load, 2710 .maxlen = sizeof(int), 2711 .mode = 0644, 2712 .proc_handler = proc_dointvec, 2713 }, 2714 { 2715 .procname = "redirect_number", 2716 .data = &ip_rt_redirect_number, 2717 .maxlen = sizeof(int), 2718 .mode = 0644, 2719 .proc_handler = proc_dointvec, 2720 }, 2721 { 2722 .procname = "redirect_silence", 2723 .data = &ip_rt_redirect_silence, 2724 .maxlen = sizeof(int), 2725 .mode = 0644, 2726 .proc_handler = proc_dointvec, 2727 }, 2728 { 2729 .procname = "error_cost", 2730 .data = &ip_rt_error_cost, 2731 .maxlen = sizeof(int), 2732 .mode = 0644, 2733 .proc_handler = proc_dointvec, 2734 }, 2735 { 2736 .procname = "error_burst", 2737 .data = &ip_rt_error_burst, 2738 .maxlen = sizeof(int), 2739 .mode = 0644, 2740 .proc_handler = proc_dointvec, 2741 }, 2742 { 2743 .procname = "gc_elasticity", 2744 .data = &ip_rt_gc_elasticity, 2745 .maxlen = sizeof(int), 2746 .mode = 0644, 2747 .proc_handler = proc_dointvec, 2748 }, 2749 { 2750 .procname = "mtu_expires", 2751 .data = &ip_rt_mtu_expires, 2752 .maxlen = sizeof(int), 2753 .mode = 0644, 2754 .proc_handler = proc_dointvec_jiffies, 2755 }, 2756 { 2757 .procname = "min_pmtu", 2758 .data = &ip_rt_min_pmtu, 2759 .maxlen = sizeof(int), 2760 .mode = 0644, 2761 .proc_handler = proc_dointvec, 2762 }, 2763 { 2764 .procname = "min_adv_mss", 2765 .data = &ip_rt_min_advmss, 2766 .maxlen = sizeof(int), 2767 .mode = 0644, 2768 .proc_handler = proc_dointvec, 2769 }, 2770 { } 2771 }; 2772 2773 static struct ctl_table ipv4_route_flush_table[] = { 2774 { 2775 .procname = "flush", 2776 .maxlen = sizeof(int), 2777 .mode = 0200, 2778 .proc_handler = ipv4_sysctl_rtcache_flush, 2779 }, 2780 { }, 2781 }; 2782 2783 static __net_init int sysctl_route_net_init(struct net *net) 2784 { 2785 struct ctl_table *tbl; 2786 2787 tbl = ipv4_route_flush_table; 2788 if (!net_eq(net, &init_net)) { 2789 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2790 if (!tbl) 2791 goto err_dup; 2792 2793 /* Don't export sysctls to unprivileged users */ 2794 if (net->user_ns != &init_user_ns) 2795 tbl[0].procname = NULL; 2796 } 2797 tbl[0].extra1 = net; 2798 2799 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2800 if (!net->ipv4.route_hdr) 2801 goto err_reg; 2802 return 0; 2803 2804 err_reg: 2805 if (tbl != ipv4_route_flush_table) 2806 kfree(tbl); 2807 err_dup: 2808 return -ENOMEM; 2809 } 2810 2811 static __net_exit void sysctl_route_net_exit(struct net *net) 2812 { 2813 struct ctl_table *tbl; 2814 2815 tbl = net->ipv4.route_hdr->ctl_table_arg; 2816 unregister_net_sysctl_table(net->ipv4.route_hdr); 2817 BUG_ON(tbl == ipv4_route_flush_table); 2818 kfree(tbl); 2819 } 2820 2821 static __net_initdata struct pernet_operations sysctl_route_ops = { 2822 .init = sysctl_route_net_init, 2823 .exit = sysctl_route_net_exit, 2824 }; 2825 #endif 2826 2827 static __net_init int rt_genid_init(struct net *net) 2828 { 2829 atomic_set(&net->ipv4.rt_genid, 0); 2830 atomic_set(&net->fnhe_genid, 0); 2831 get_random_bytes(&net->ipv4.dev_addr_genid, 2832 sizeof(net->ipv4.dev_addr_genid)); 2833 return 0; 2834 } 2835 2836 static __net_initdata struct pernet_operations rt_genid_ops = { 2837 .init = rt_genid_init, 2838 }; 2839 2840 static int __net_init ipv4_inetpeer_init(struct net *net) 2841 { 2842 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 2843 2844 if (!bp) 2845 return -ENOMEM; 2846 inet_peer_base_init(bp); 2847 net->ipv4.peers = bp; 2848 return 0; 2849 } 2850 2851 static void __net_exit ipv4_inetpeer_exit(struct net *net) 2852 { 2853 struct inet_peer_base *bp = net->ipv4.peers; 2854 2855 net->ipv4.peers = NULL; 2856 inetpeer_invalidate_tree(bp); 2857 kfree(bp); 2858 } 2859 2860 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 2861 .init = ipv4_inetpeer_init, 2862 .exit = ipv4_inetpeer_exit, 2863 }; 2864 2865 #ifdef CONFIG_IP_ROUTE_CLASSID 2866 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 2867 #endif /* CONFIG_IP_ROUTE_CLASSID */ 2868 2869 int __init ip_rt_init(void) 2870 { 2871 int rc = 0; 2872 int cpu; 2873 2874 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 2875 if (!ip_idents) 2876 panic("IP: failed to allocate ip_idents\n"); 2877 2878 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 2879 2880 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 2881 if (!ip_tstamps) 2882 panic("IP: failed to allocate ip_tstamps\n"); 2883 2884 for_each_possible_cpu(cpu) { 2885 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 2886 2887 INIT_LIST_HEAD(&ul->head); 2888 spin_lock_init(&ul->lock); 2889 } 2890 #ifdef CONFIG_IP_ROUTE_CLASSID 2891 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 2892 if (!ip_rt_acct) 2893 panic("IP: failed to allocate ip_rt_acct\n"); 2894 #endif 2895 2896 ipv4_dst_ops.kmem_cachep = 2897 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 2898 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2899 2900 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 2901 2902 if (dst_entries_init(&ipv4_dst_ops) < 0) 2903 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 2904 2905 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 2906 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 2907 2908 ipv4_dst_ops.gc_thresh = ~0; 2909 ip_rt_max_size = INT_MAX; 2910 2911 devinet_init(); 2912 ip_fib_init(); 2913 2914 if (ip_rt_proc_init()) 2915 pr_err("Unable to create route proc files\n"); 2916 #ifdef CONFIG_XFRM 2917 xfrm_init(); 2918 xfrm4_init(); 2919 #endif 2920 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); 2921 2922 #ifdef CONFIG_SYSCTL 2923 register_pernet_subsys(&sysctl_route_ops); 2924 #endif 2925 register_pernet_subsys(&rt_genid_ops); 2926 register_pernet_subsys(&ipv4_inetpeer_ops); 2927 return rc; 2928 } 2929 2930 #ifdef CONFIG_SYSCTL 2931 /* 2932 * We really need to sanitize the damn ipv4 init order, then all 2933 * this nonsense will go away. 2934 */ 2935 void __init ip_static_sysctl_init(void) 2936 { 2937 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 2938 } 2939 #endif 2940