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 delta = 0; 480 481 if (old != now && cmpxchg(p_tstamp, old, now) == old) 482 delta = prandom_u32_max(now - old); 483 484 return atomic_add_return(segs + delta, p_id) - segs; 485 } 486 EXPORT_SYMBOL(ip_idents_reserve); 487 488 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 489 { 490 static u32 ip_idents_hashrnd __read_mostly; 491 u32 hash, id; 492 493 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); 494 495 hash = jhash_3words((__force u32)iph->daddr, 496 (__force u32)iph->saddr, 497 iph->protocol ^ net_hash_mix(net), 498 ip_idents_hashrnd); 499 id = ip_idents_reserve(hash, segs); 500 iph->id = htons(id); 501 } 502 EXPORT_SYMBOL(__ip_select_ident); 503 504 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk, 505 const struct iphdr *iph, 506 int oif, u8 tos, 507 u8 prot, u32 mark, int flow_flags) 508 { 509 if (sk) { 510 const struct inet_sock *inet = inet_sk(sk); 511 512 oif = sk->sk_bound_dev_if; 513 mark = sk->sk_mark; 514 tos = RT_CONN_FLAGS(sk); 515 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 516 } 517 flowi4_init_output(fl4, oif, mark, tos, 518 RT_SCOPE_UNIVERSE, prot, 519 flow_flags, 520 iph->daddr, iph->saddr, 0, 0); 521 } 522 523 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 524 const struct sock *sk) 525 { 526 const struct iphdr *iph = ip_hdr(skb); 527 int oif = skb->dev->ifindex; 528 u8 tos = RT_TOS(iph->tos); 529 u8 prot = iph->protocol; 530 u32 mark = skb->mark; 531 532 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0); 533 } 534 535 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 536 { 537 const struct inet_sock *inet = inet_sk(sk); 538 const struct ip_options_rcu *inet_opt; 539 __be32 daddr = inet->inet_daddr; 540 541 rcu_read_lock(); 542 inet_opt = rcu_dereference(inet->inet_opt); 543 if (inet_opt && inet_opt->opt.srr) 544 daddr = inet_opt->opt.faddr; 545 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 547 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 548 inet_sk_flowi_flags(sk), 549 daddr, inet->inet_saddr, 0, 0); 550 rcu_read_unlock(); 551 } 552 553 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 554 const struct sk_buff *skb) 555 { 556 if (skb) 557 build_skb_flow_key(fl4, skb, sk); 558 else 559 build_sk_flow_key(fl4, sk); 560 } 561 562 static inline void rt_free(struct rtable *rt) 563 { 564 call_rcu(&rt->dst.rcu_head, dst_rcu_free); 565 } 566 567 static DEFINE_SPINLOCK(fnhe_lock); 568 569 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 570 { 571 struct rtable *rt; 572 573 rt = rcu_dereference(fnhe->fnhe_rth_input); 574 if (rt) { 575 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 576 rt_free(rt); 577 } 578 rt = rcu_dereference(fnhe->fnhe_rth_output); 579 if (rt) { 580 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 581 rt_free(rt); 582 } 583 } 584 585 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 586 { 587 struct fib_nh_exception *fnhe, *oldest; 588 589 oldest = rcu_dereference(hash->chain); 590 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 591 fnhe = rcu_dereference(fnhe->fnhe_next)) { 592 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 593 oldest = fnhe; 594 } 595 fnhe_flush_routes(oldest); 596 return oldest; 597 } 598 599 static inline u32 fnhe_hashfun(__be32 daddr) 600 { 601 static u32 fnhe_hashrnd __read_mostly; 602 u32 hval; 603 604 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 605 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 606 return hash_32(hval, FNHE_HASH_SHIFT); 607 } 608 609 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 610 { 611 rt->rt_pmtu = fnhe->fnhe_pmtu; 612 rt->dst.expires = fnhe->fnhe_expires; 613 614 if (fnhe->fnhe_gw) { 615 rt->rt_flags |= RTCF_REDIRECTED; 616 rt->rt_gateway = fnhe->fnhe_gw; 617 rt->rt_uses_gateway = 1; 618 } 619 } 620 621 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 622 u32 pmtu, unsigned long expires) 623 { 624 struct fnhe_hash_bucket *hash; 625 struct fib_nh_exception *fnhe; 626 struct rtable *rt; 627 unsigned int i; 628 int depth; 629 u32 hval = fnhe_hashfun(daddr); 630 631 spin_lock_bh(&fnhe_lock); 632 633 hash = rcu_dereference(nh->nh_exceptions); 634 if (!hash) { 635 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 636 if (!hash) 637 goto out_unlock; 638 rcu_assign_pointer(nh->nh_exceptions, hash); 639 } 640 641 hash += hval; 642 643 depth = 0; 644 for (fnhe = rcu_dereference(hash->chain); fnhe; 645 fnhe = rcu_dereference(fnhe->fnhe_next)) { 646 if (fnhe->fnhe_daddr == daddr) 647 break; 648 depth++; 649 } 650 651 if (fnhe) { 652 if (gw) 653 fnhe->fnhe_gw = gw; 654 if (pmtu) { 655 fnhe->fnhe_pmtu = pmtu; 656 fnhe->fnhe_expires = max(1UL, expires); 657 } 658 /* Update all cached dsts too */ 659 rt = rcu_dereference(fnhe->fnhe_rth_input); 660 if (rt) 661 fill_route_from_fnhe(rt, fnhe); 662 rt = rcu_dereference(fnhe->fnhe_rth_output); 663 if (rt) 664 fill_route_from_fnhe(rt, fnhe); 665 } else { 666 if (depth > FNHE_RECLAIM_DEPTH) 667 fnhe = fnhe_oldest(hash); 668 else { 669 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 670 if (!fnhe) 671 goto out_unlock; 672 673 fnhe->fnhe_next = hash->chain; 674 rcu_assign_pointer(hash->chain, fnhe); 675 } 676 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev)); 677 fnhe->fnhe_daddr = daddr; 678 fnhe->fnhe_gw = gw; 679 fnhe->fnhe_pmtu = pmtu; 680 fnhe->fnhe_expires = expires; 681 682 /* Exception created; mark the cached routes for the nexthop 683 * stale, so anyone caching it rechecks if this exception 684 * applies to them. 685 */ 686 rt = rcu_dereference(nh->nh_rth_input); 687 if (rt) 688 rt->dst.obsolete = DST_OBSOLETE_KILL; 689 690 for_each_possible_cpu(i) { 691 struct rtable __rcu **prt; 692 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 693 rt = rcu_dereference(*prt); 694 if (rt) 695 rt->dst.obsolete = DST_OBSOLETE_KILL; 696 } 697 } 698 699 fnhe->fnhe_stamp = jiffies; 700 701 out_unlock: 702 spin_unlock_bh(&fnhe_lock); 703 } 704 705 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 706 bool kill_route) 707 { 708 __be32 new_gw = icmp_hdr(skb)->un.gateway; 709 __be32 old_gw = ip_hdr(skb)->saddr; 710 struct net_device *dev = skb->dev; 711 struct in_device *in_dev; 712 struct fib_result res; 713 struct neighbour *n; 714 struct net *net; 715 716 switch (icmp_hdr(skb)->code & 7) { 717 case ICMP_REDIR_NET: 718 case ICMP_REDIR_NETTOS: 719 case ICMP_REDIR_HOST: 720 case ICMP_REDIR_HOSTTOS: 721 break; 722 723 default: 724 return; 725 } 726 727 if (rt->rt_gateway != old_gw) 728 return; 729 730 in_dev = __in_dev_get_rcu(dev); 731 if (!in_dev) 732 return; 733 734 net = dev_net(dev); 735 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 736 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 737 ipv4_is_zeronet(new_gw)) 738 goto reject_redirect; 739 740 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 741 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 742 goto reject_redirect; 743 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 744 goto reject_redirect; 745 } else { 746 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 747 goto reject_redirect; 748 } 749 750 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw); 751 if (!IS_ERR(n)) { 752 if (!(n->nud_state & NUD_VALID)) { 753 neigh_event_send(n, NULL); 754 } else { 755 if (fib_lookup(net, fl4, &res, 0) == 0) { 756 struct fib_nh *nh = &FIB_RES_NH(res); 757 758 update_or_create_fnhe(nh, fl4->daddr, new_gw, 759 0, jiffies + ip_rt_gc_timeout); 760 } 761 if (kill_route) 762 rt->dst.obsolete = DST_OBSOLETE_KILL; 763 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 764 } 765 neigh_release(n); 766 } 767 return; 768 769 reject_redirect: 770 #ifdef CONFIG_IP_ROUTE_VERBOSE 771 if (IN_DEV_LOG_MARTIANS(in_dev)) { 772 const struct iphdr *iph = (const struct iphdr *) skb->data; 773 __be32 daddr = iph->daddr; 774 __be32 saddr = iph->saddr; 775 776 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 777 " Advised path = %pI4 -> %pI4\n", 778 &old_gw, dev->name, &new_gw, 779 &saddr, &daddr); 780 } 781 #endif 782 ; 783 } 784 785 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 786 { 787 struct rtable *rt; 788 struct flowi4 fl4; 789 const struct iphdr *iph = (const struct iphdr *) skb->data; 790 int oif = skb->dev->ifindex; 791 u8 tos = RT_TOS(iph->tos); 792 u8 prot = iph->protocol; 793 u32 mark = skb->mark; 794 795 rt = (struct rtable *) dst; 796 797 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0); 798 __ip_do_redirect(rt, skb, &fl4, true); 799 } 800 801 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 802 { 803 struct rtable *rt = (struct rtable *)dst; 804 struct dst_entry *ret = dst; 805 806 if (rt) { 807 if (dst->obsolete > 0) { 808 ip_rt_put(rt); 809 ret = NULL; 810 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 811 rt->dst.expires) { 812 ip_rt_put(rt); 813 ret = NULL; 814 } 815 } 816 return ret; 817 } 818 819 /* 820 * Algorithm: 821 * 1. The first ip_rt_redirect_number redirects are sent 822 * with exponential backoff, then we stop sending them at all, 823 * assuming that the host ignores our redirects. 824 * 2. If we did not see packets requiring redirects 825 * during ip_rt_redirect_silence, we assume that the host 826 * forgot redirected route and start to send redirects again. 827 * 828 * This algorithm is much cheaper and more intelligent than dumb load limiting 829 * in icmp.c. 830 * 831 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 832 * and "frag. need" (breaks PMTU discovery) in icmp.c. 833 */ 834 835 void ip_rt_send_redirect(struct sk_buff *skb) 836 { 837 struct rtable *rt = skb_rtable(skb); 838 struct in_device *in_dev; 839 struct inet_peer *peer; 840 struct net *net; 841 int log_martians; 842 int vif; 843 844 rcu_read_lock(); 845 in_dev = __in_dev_get_rcu(rt->dst.dev); 846 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 847 rcu_read_unlock(); 848 return; 849 } 850 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 851 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 852 rcu_read_unlock(); 853 854 net = dev_net(rt->dst.dev); 855 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 856 if (!peer) { 857 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 858 rt_nexthop(rt, ip_hdr(skb)->daddr)); 859 return; 860 } 861 862 /* No redirected packets during ip_rt_redirect_silence; 863 * reset the algorithm. 864 */ 865 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 866 peer->rate_tokens = 0; 867 868 /* Too many ignored redirects; do not send anything 869 * set dst.rate_last to the last seen redirected packet. 870 */ 871 if (peer->rate_tokens >= ip_rt_redirect_number) { 872 peer->rate_last = jiffies; 873 goto out_put_peer; 874 } 875 876 /* Check for load limit; set rate_last to the latest sent 877 * redirect. 878 */ 879 if (peer->rate_tokens == 0 || 880 time_after(jiffies, 881 (peer->rate_last + 882 (ip_rt_redirect_load << peer->rate_tokens)))) { 883 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 884 885 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 886 peer->rate_last = jiffies; 887 ++peer->rate_tokens; 888 #ifdef CONFIG_IP_ROUTE_VERBOSE 889 if (log_martians && 890 peer->rate_tokens == ip_rt_redirect_number) 891 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 892 &ip_hdr(skb)->saddr, inet_iif(skb), 893 &ip_hdr(skb)->daddr, &gw); 894 #endif 895 } 896 out_put_peer: 897 inet_putpeer(peer); 898 } 899 900 static int ip_error(struct sk_buff *skb) 901 { 902 struct in_device *in_dev = __in_dev_get_rcu(skb->dev); 903 struct rtable *rt = skb_rtable(skb); 904 struct inet_peer *peer; 905 unsigned long now; 906 struct net *net; 907 bool send; 908 int code; 909 910 /* IP on this device is disabled. */ 911 if (!in_dev) 912 goto out; 913 914 net = dev_net(rt->dst.dev); 915 if (!IN_DEV_FORWARD(in_dev)) { 916 switch (rt->dst.error) { 917 case EHOSTUNREACH: 918 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS); 919 break; 920 921 case ENETUNREACH: 922 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES); 923 break; 924 } 925 goto out; 926 } 927 928 switch (rt->dst.error) { 929 case EINVAL: 930 default: 931 goto out; 932 case EHOSTUNREACH: 933 code = ICMP_HOST_UNREACH; 934 break; 935 case ENETUNREACH: 936 code = ICMP_NET_UNREACH; 937 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES); 938 break; 939 case EACCES: 940 code = ICMP_PKT_FILTERED; 941 break; 942 } 943 944 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 945 l3mdev_master_ifindex(skb->dev), 1); 946 947 send = true; 948 if (peer) { 949 now = jiffies; 950 peer->rate_tokens += now - peer->rate_last; 951 if (peer->rate_tokens > ip_rt_error_burst) 952 peer->rate_tokens = ip_rt_error_burst; 953 peer->rate_last = now; 954 if (peer->rate_tokens >= ip_rt_error_cost) 955 peer->rate_tokens -= ip_rt_error_cost; 956 else 957 send = false; 958 inet_putpeer(peer); 959 } 960 if (send) 961 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 962 963 out: kfree_skb(skb); 964 return 0; 965 } 966 967 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 968 { 969 struct dst_entry *dst = &rt->dst; 970 struct fib_result res; 971 972 if (dst_metric_locked(dst, RTAX_MTU)) 973 return; 974 975 if (ipv4_mtu(dst) < mtu) 976 return; 977 978 if (mtu < ip_rt_min_pmtu) 979 mtu = ip_rt_min_pmtu; 980 981 if (rt->rt_pmtu == mtu && 982 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 983 return; 984 985 rcu_read_lock(); 986 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 987 struct fib_nh *nh = &FIB_RES_NH(res); 988 989 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, 990 jiffies + ip_rt_mtu_expires); 991 } 992 rcu_read_unlock(); 993 } 994 995 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 996 struct sk_buff *skb, u32 mtu) 997 { 998 struct rtable *rt = (struct rtable *) dst; 999 struct flowi4 fl4; 1000 1001 ip_rt_build_flow_key(&fl4, sk, skb); 1002 __ip_rt_update_pmtu(rt, &fl4, mtu); 1003 } 1004 1005 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1006 int oif, u32 mark, u8 protocol, int flow_flags) 1007 { 1008 const struct iphdr *iph = (const struct iphdr *) skb->data; 1009 struct flowi4 fl4; 1010 struct rtable *rt; 1011 1012 if (!mark) 1013 mark = IP4_REPLY_MARK(net, skb->mark); 1014 1015 __build_flow_key(&fl4, NULL, iph, oif, 1016 RT_TOS(iph->tos), protocol, mark, flow_flags); 1017 rt = __ip_route_output_key(net, &fl4); 1018 if (!IS_ERR(rt)) { 1019 __ip_rt_update_pmtu(rt, &fl4, mtu); 1020 ip_rt_put(rt); 1021 } 1022 } 1023 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1024 1025 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1026 { 1027 const struct iphdr *iph = (const struct iphdr *) skb->data; 1028 struct flowi4 fl4; 1029 struct rtable *rt; 1030 1031 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1032 1033 if (!fl4.flowi4_mark) 1034 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1035 1036 rt = __ip_route_output_key(sock_net(sk), &fl4); 1037 if (!IS_ERR(rt)) { 1038 __ip_rt_update_pmtu(rt, &fl4, mtu); 1039 ip_rt_put(rt); 1040 } 1041 } 1042 1043 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1044 { 1045 const struct iphdr *iph = (const struct iphdr *) skb->data; 1046 struct flowi4 fl4; 1047 struct rtable *rt; 1048 struct dst_entry *odst = NULL; 1049 bool new = false; 1050 1051 bh_lock_sock(sk); 1052 1053 if (!ip_sk_accept_pmtu(sk)) 1054 goto out; 1055 1056 odst = sk_dst_get(sk); 1057 1058 if (sock_owned_by_user(sk) || !odst) { 1059 __ipv4_sk_update_pmtu(skb, sk, mtu); 1060 goto out; 1061 } 1062 1063 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1064 1065 rt = (struct rtable *)odst; 1066 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1067 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1068 if (IS_ERR(rt)) 1069 goto out; 1070 1071 new = true; 1072 } 1073 1074 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu); 1075 1076 if (!dst_check(&rt->dst, 0)) { 1077 if (new) 1078 dst_release(&rt->dst); 1079 1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1081 if (IS_ERR(rt)) 1082 goto out; 1083 1084 new = true; 1085 } 1086 1087 if (new) 1088 sk_dst_set(sk, &rt->dst); 1089 1090 out: 1091 bh_unlock_sock(sk); 1092 dst_release(odst); 1093 } 1094 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1095 1096 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1097 int oif, u32 mark, u8 protocol, int flow_flags) 1098 { 1099 const struct iphdr *iph = (const struct iphdr *) skb->data; 1100 struct flowi4 fl4; 1101 struct rtable *rt; 1102 1103 __build_flow_key(&fl4, NULL, iph, oif, 1104 RT_TOS(iph->tos), protocol, mark, flow_flags); 1105 rt = __ip_route_output_key(net, &fl4); 1106 if (!IS_ERR(rt)) { 1107 __ip_do_redirect(rt, skb, &fl4, false); 1108 ip_rt_put(rt); 1109 } 1110 } 1111 EXPORT_SYMBOL_GPL(ipv4_redirect); 1112 1113 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1114 { 1115 const struct iphdr *iph = (const struct iphdr *) skb->data; 1116 struct flowi4 fl4; 1117 struct rtable *rt; 1118 1119 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1120 rt = __ip_route_output_key(sock_net(sk), &fl4); 1121 if (!IS_ERR(rt)) { 1122 __ip_do_redirect(rt, skb, &fl4, false); 1123 ip_rt_put(rt); 1124 } 1125 } 1126 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1127 1128 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1129 { 1130 struct rtable *rt = (struct rtable *) dst; 1131 1132 /* All IPV4 dsts are created with ->obsolete set to the value 1133 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1134 * into this function always. 1135 * 1136 * When a PMTU/redirect information update invalidates a route, 1137 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1138 * DST_OBSOLETE_DEAD by dst_free(). 1139 */ 1140 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1141 return NULL; 1142 return dst; 1143 } 1144 1145 static void ipv4_link_failure(struct sk_buff *skb) 1146 { 1147 struct rtable *rt; 1148 1149 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1150 1151 rt = skb_rtable(skb); 1152 if (rt) 1153 dst_set_expires(&rt->dst, 0); 1154 } 1155 1156 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1157 { 1158 pr_debug("%s: %pI4 -> %pI4, %s\n", 1159 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1160 skb->dev ? skb->dev->name : "?"); 1161 kfree_skb(skb); 1162 WARN_ON(1); 1163 return 0; 1164 } 1165 1166 /* 1167 We do not cache source address of outgoing interface, 1168 because it is used only by IP RR, TS and SRR options, 1169 so that it out of fast path. 1170 1171 BTW remember: "addr" is allowed to be not aligned 1172 in IP options! 1173 */ 1174 1175 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1176 { 1177 __be32 src; 1178 1179 if (rt_is_output_route(rt)) 1180 src = ip_hdr(skb)->saddr; 1181 else { 1182 struct fib_result res; 1183 struct flowi4 fl4; 1184 struct iphdr *iph; 1185 1186 iph = ip_hdr(skb); 1187 1188 memset(&fl4, 0, sizeof(fl4)); 1189 fl4.daddr = iph->daddr; 1190 fl4.saddr = iph->saddr; 1191 fl4.flowi4_tos = RT_TOS(iph->tos); 1192 fl4.flowi4_oif = rt->dst.dev->ifindex; 1193 fl4.flowi4_iif = skb->dev->ifindex; 1194 fl4.flowi4_mark = skb->mark; 1195 1196 rcu_read_lock(); 1197 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1198 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1199 else 1200 src = inet_select_addr(rt->dst.dev, 1201 rt_nexthop(rt, iph->daddr), 1202 RT_SCOPE_UNIVERSE); 1203 rcu_read_unlock(); 1204 } 1205 memcpy(addr, &src, 4); 1206 } 1207 1208 #ifdef CONFIG_IP_ROUTE_CLASSID 1209 static void set_class_tag(struct rtable *rt, u32 tag) 1210 { 1211 if (!(rt->dst.tclassid & 0xFFFF)) 1212 rt->dst.tclassid |= tag & 0xFFFF; 1213 if (!(rt->dst.tclassid & 0xFFFF0000)) 1214 rt->dst.tclassid |= tag & 0xFFFF0000; 1215 } 1216 #endif 1217 1218 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1219 { 1220 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); 1221 1222 if (advmss == 0) { 1223 advmss = max_t(unsigned int, dst->dev->mtu - 40, 1224 ip_rt_min_advmss); 1225 if (advmss > 65535 - 40) 1226 advmss = 65535 - 40; 1227 } 1228 return advmss; 1229 } 1230 1231 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1232 { 1233 const struct rtable *rt = (const struct rtable *) dst; 1234 unsigned int mtu = rt->rt_pmtu; 1235 1236 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1237 mtu = dst_metric_raw(dst, RTAX_MTU); 1238 1239 if (mtu) 1240 return mtu; 1241 1242 mtu = dst->dev->mtu; 1243 1244 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { 1245 if (rt->rt_uses_gateway && mtu > 576) 1246 mtu = 576; 1247 } 1248 1249 return min_t(unsigned int, mtu, IP_MAX_MTU); 1250 } 1251 1252 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1253 { 1254 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1255 struct fib_nh_exception *fnhe; 1256 u32 hval; 1257 1258 if (!hash) 1259 return NULL; 1260 1261 hval = fnhe_hashfun(daddr); 1262 1263 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1264 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1265 if (fnhe->fnhe_daddr == daddr) 1266 return fnhe; 1267 } 1268 return NULL; 1269 } 1270 1271 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1272 __be32 daddr) 1273 { 1274 bool ret = false; 1275 1276 spin_lock_bh(&fnhe_lock); 1277 1278 if (daddr == fnhe->fnhe_daddr) { 1279 struct rtable __rcu **porig; 1280 struct rtable *orig; 1281 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1282 1283 if (rt_is_input_route(rt)) 1284 porig = &fnhe->fnhe_rth_input; 1285 else 1286 porig = &fnhe->fnhe_rth_output; 1287 orig = rcu_dereference(*porig); 1288 1289 if (fnhe->fnhe_genid != genid) { 1290 fnhe->fnhe_genid = genid; 1291 fnhe->fnhe_gw = 0; 1292 fnhe->fnhe_pmtu = 0; 1293 fnhe->fnhe_expires = 0; 1294 fnhe_flush_routes(fnhe); 1295 orig = NULL; 1296 } 1297 fill_route_from_fnhe(rt, fnhe); 1298 if (!rt->rt_gateway) 1299 rt->rt_gateway = daddr; 1300 1301 if (!(rt->dst.flags & DST_NOCACHE)) { 1302 rcu_assign_pointer(*porig, rt); 1303 if (orig) 1304 rt_free(orig); 1305 ret = true; 1306 } 1307 1308 fnhe->fnhe_stamp = jiffies; 1309 } 1310 spin_unlock_bh(&fnhe_lock); 1311 1312 return ret; 1313 } 1314 1315 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1316 { 1317 struct rtable *orig, *prev, **p; 1318 bool ret = true; 1319 1320 if (rt_is_input_route(rt)) { 1321 p = (struct rtable **)&nh->nh_rth_input; 1322 } else { 1323 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1324 } 1325 orig = *p; 1326 1327 prev = cmpxchg(p, orig, rt); 1328 if (prev == orig) { 1329 if (orig) 1330 rt_free(orig); 1331 } else 1332 ret = false; 1333 1334 return ret; 1335 } 1336 1337 struct uncached_list { 1338 spinlock_t lock; 1339 struct list_head head; 1340 }; 1341 1342 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1343 1344 static void rt_add_uncached_list(struct rtable *rt) 1345 { 1346 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1347 1348 rt->rt_uncached_list = ul; 1349 1350 spin_lock_bh(&ul->lock); 1351 list_add_tail(&rt->rt_uncached, &ul->head); 1352 spin_unlock_bh(&ul->lock); 1353 } 1354 1355 static void ipv4_dst_destroy(struct dst_entry *dst) 1356 { 1357 struct rtable *rt = (struct rtable *) dst; 1358 1359 if (!list_empty(&rt->rt_uncached)) { 1360 struct uncached_list *ul = rt->rt_uncached_list; 1361 1362 spin_lock_bh(&ul->lock); 1363 list_del(&rt->rt_uncached); 1364 spin_unlock_bh(&ul->lock); 1365 } 1366 } 1367 1368 void rt_flush_dev(struct net_device *dev) 1369 { 1370 struct net *net = dev_net(dev); 1371 struct rtable *rt; 1372 int cpu; 1373 1374 for_each_possible_cpu(cpu) { 1375 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1376 1377 spin_lock_bh(&ul->lock); 1378 list_for_each_entry(rt, &ul->head, rt_uncached) { 1379 if (rt->dst.dev != dev) 1380 continue; 1381 rt->dst.dev = net->loopback_dev; 1382 dev_hold(rt->dst.dev); 1383 dev_put(dev); 1384 } 1385 spin_unlock_bh(&ul->lock); 1386 } 1387 } 1388 1389 static bool rt_cache_valid(const struct rtable *rt) 1390 { 1391 return rt && 1392 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1393 !rt_is_expired(rt); 1394 } 1395 1396 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1397 const struct fib_result *res, 1398 struct fib_nh_exception *fnhe, 1399 struct fib_info *fi, u16 type, u32 itag) 1400 { 1401 bool cached = false; 1402 1403 if (fi) { 1404 struct fib_nh *nh = &FIB_RES_NH(*res); 1405 1406 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1407 rt->rt_gateway = nh->nh_gw; 1408 rt->rt_uses_gateway = 1; 1409 } 1410 dst_init_metrics(&rt->dst, fi->fib_metrics, true); 1411 #ifdef CONFIG_IP_ROUTE_CLASSID 1412 rt->dst.tclassid = nh->nh_tclassid; 1413 #endif 1414 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1415 if (unlikely(fnhe)) 1416 cached = rt_bind_exception(rt, fnhe, daddr); 1417 else if (!(rt->dst.flags & DST_NOCACHE)) 1418 cached = rt_cache_route(nh, rt); 1419 if (unlikely(!cached)) { 1420 /* Routes we intend to cache in nexthop exception or 1421 * FIB nexthop have the DST_NOCACHE bit clear. 1422 * However, if we are unsuccessful at storing this 1423 * route into the cache we really need to set it. 1424 */ 1425 rt->dst.flags |= DST_NOCACHE; 1426 if (!rt->rt_gateway) 1427 rt->rt_gateway = daddr; 1428 rt_add_uncached_list(rt); 1429 } 1430 } else 1431 rt_add_uncached_list(rt); 1432 1433 #ifdef CONFIG_IP_ROUTE_CLASSID 1434 #ifdef CONFIG_IP_MULTIPLE_TABLES 1435 set_class_tag(rt, res->tclassid); 1436 #endif 1437 set_class_tag(rt, itag); 1438 #endif 1439 } 1440 1441 static struct rtable *rt_dst_alloc(struct net_device *dev, 1442 unsigned int flags, u16 type, 1443 bool nopolicy, bool noxfrm, bool will_cache) 1444 { 1445 struct rtable *rt; 1446 1447 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1448 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) | 1449 (nopolicy ? DST_NOPOLICY : 0) | 1450 (noxfrm ? DST_NOXFRM : 0)); 1451 1452 if (rt) { 1453 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1454 rt->rt_flags = flags; 1455 rt->rt_type = type; 1456 rt->rt_is_input = 0; 1457 rt->rt_iif = 0; 1458 rt->rt_pmtu = 0; 1459 rt->rt_gateway = 0; 1460 rt->rt_uses_gateway = 0; 1461 rt->rt_table_id = 0; 1462 INIT_LIST_HEAD(&rt->rt_uncached); 1463 1464 rt->dst.output = ip_output; 1465 if (flags & RTCF_LOCAL) 1466 rt->dst.input = ip_local_deliver; 1467 } 1468 1469 return rt; 1470 } 1471 1472 /* called in rcu_read_lock() section */ 1473 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1474 u8 tos, struct net_device *dev, int our) 1475 { 1476 struct rtable *rth; 1477 struct in_device *in_dev = __in_dev_get_rcu(dev); 1478 unsigned int flags = RTCF_MULTICAST; 1479 u32 itag = 0; 1480 int err; 1481 1482 /* Primary sanity checks. */ 1483 1484 if (!in_dev) 1485 return -EINVAL; 1486 1487 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1488 skb->protocol != htons(ETH_P_IP)) 1489 goto e_inval; 1490 1491 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1492 goto e_inval; 1493 1494 if (ipv4_is_zeronet(saddr)) { 1495 if (!ipv4_is_local_multicast(daddr)) 1496 goto e_inval; 1497 } else { 1498 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1499 in_dev, &itag); 1500 if (err < 0) 1501 goto e_err; 1502 } 1503 if (our) 1504 flags |= RTCF_LOCAL; 1505 1506 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1507 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1508 if (!rth) 1509 goto e_nobufs; 1510 1511 #ifdef CONFIG_IP_ROUTE_CLASSID 1512 rth->dst.tclassid = itag; 1513 #endif 1514 rth->dst.output = ip_rt_bug; 1515 rth->rt_is_input= 1; 1516 1517 #ifdef CONFIG_IP_MROUTE 1518 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1519 rth->dst.input = ip_mr_input; 1520 #endif 1521 RT_CACHE_STAT_INC(in_slow_mc); 1522 1523 skb_dst_set(skb, &rth->dst); 1524 return 0; 1525 1526 e_nobufs: 1527 return -ENOBUFS; 1528 e_inval: 1529 return -EINVAL; 1530 e_err: 1531 return err; 1532 } 1533 1534 1535 static void ip_handle_martian_source(struct net_device *dev, 1536 struct in_device *in_dev, 1537 struct sk_buff *skb, 1538 __be32 daddr, 1539 __be32 saddr) 1540 { 1541 RT_CACHE_STAT_INC(in_martian_src); 1542 #ifdef CONFIG_IP_ROUTE_VERBOSE 1543 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1544 /* 1545 * RFC1812 recommendation, if source is martian, 1546 * the only hint is MAC header. 1547 */ 1548 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1549 &daddr, &saddr, dev->name); 1550 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1551 print_hex_dump(KERN_WARNING, "ll header: ", 1552 DUMP_PREFIX_OFFSET, 16, 1, 1553 skb_mac_header(skb), 1554 dev->hard_header_len, true); 1555 } 1556 } 1557 #endif 1558 } 1559 1560 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1561 { 1562 struct fnhe_hash_bucket *hash; 1563 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1564 u32 hval = fnhe_hashfun(daddr); 1565 1566 spin_lock_bh(&fnhe_lock); 1567 1568 hash = rcu_dereference_protected(nh->nh_exceptions, 1569 lockdep_is_held(&fnhe_lock)); 1570 hash += hval; 1571 1572 fnhe_p = &hash->chain; 1573 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1574 while (fnhe) { 1575 if (fnhe->fnhe_daddr == daddr) { 1576 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1577 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1578 fnhe_flush_routes(fnhe); 1579 kfree_rcu(fnhe, rcu); 1580 break; 1581 } 1582 fnhe_p = &fnhe->fnhe_next; 1583 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1584 lockdep_is_held(&fnhe_lock)); 1585 } 1586 1587 spin_unlock_bh(&fnhe_lock); 1588 } 1589 1590 /* called in rcu_read_lock() section */ 1591 static int __mkroute_input(struct sk_buff *skb, 1592 const struct fib_result *res, 1593 struct in_device *in_dev, 1594 __be32 daddr, __be32 saddr, u32 tos) 1595 { 1596 struct fib_nh_exception *fnhe; 1597 struct rtable *rth; 1598 int err; 1599 struct in_device *out_dev; 1600 bool do_cache; 1601 u32 itag = 0; 1602 1603 /* get a working reference to the output device */ 1604 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1605 if (!out_dev) { 1606 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1607 return -EINVAL; 1608 } 1609 1610 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1611 in_dev->dev, in_dev, &itag); 1612 if (err < 0) { 1613 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1614 saddr); 1615 1616 goto cleanup; 1617 } 1618 1619 do_cache = res->fi && !itag; 1620 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1621 skb->protocol == htons(ETH_P_IP) && 1622 (IN_DEV_SHARED_MEDIA(out_dev) || 1623 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1624 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1625 1626 if (skb->protocol != htons(ETH_P_IP)) { 1627 /* Not IP (i.e. ARP). Do not create route, if it is 1628 * invalid for proxy arp. DNAT routes are always valid. 1629 * 1630 * Proxy arp feature have been extended to allow, ARP 1631 * replies back to the same interface, to support 1632 * Private VLAN switch technologies. See arp.c. 1633 */ 1634 if (out_dev == in_dev && 1635 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1636 err = -EINVAL; 1637 goto cleanup; 1638 } 1639 } 1640 1641 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1642 if (do_cache) { 1643 if (fnhe) { 1644 rth = rcu_dereference(fnhe->fnhe_rth_input); 1645 if (rth && rth->dst.expires && 1646 time_after(jiffies, rth->dst.expires)) { 1647 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1648 fnhe = NULL; 1649 } else { 1650 goto rt_cache; 1651 } 1652 } 1653 1654 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1655 1656 rt_cache: 1657 if (rt_cache_valid(rth)) { 1658 skb_dst_set_noref(skb, &rth->dst); 1659 goto out; 1660 } 1661 } 1662 1663 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1664 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1665 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1666 if (!rth) { 1667 err = -ENOBUFS; 1668 goto cleanup; 1669 } 1670 1671 rth->rt_is_input = 1; 1672 if (res->table) 1673 rth->rt_table_id = res->table->tb_id; 1674 RT_CACHE_STAT_INC(in_slow_tot); 1675 1676 rth->dst.input = ip_forward; 1677 1678 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag); 1679 if (lwtunnel_output_redirect(rth->dst.lwtstate)) { 1680 rth->dst.lwtstate->orig_output = rth->dst.output; 1681 rth->dst.output = lwtunnel_output; 1682 } 1683 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 1684 rth->dst.lwtstate->orig_input = rth->dst.input; 1685 rth->dst.input = lwtunnel_input; 1686 } 1687 skb_dst_set(skb, &rth->dst); 1688 out: 1689 err = 0; 1690 cleanup: 1691 return err; 1692 } 1693 1694 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1695 1696 /* To make ICMP packets follow the right flow, the multipath hash is 1697 * calculated from the inner IP addresses in reverse order. 1698 */ 1699 static int ip_multipath_icmp_hash(struct sk_buff *skb) 1700 { 1701 const struct iphdr *outer_iph = ip_hdr(skb); 1702 struct icmphdr _icmph; 1703 const struct icmphdr *icmph; 1704 struct iphdr _inner_iph; 1705 const struct iphdr *inner_iph; 1706 1707 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1708 goto standard_hash; 1709 1710 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1711 &_icmph); 1712 if (!icmph) 1713 goto standard_hash; 1714 1715 if (icmph->type != ICMP_DEST_UNREACH && 1716 icmph->type != ICMP_REDIRECT && 1717 icmph->type != ICMP_TIME_EXCEEDED && 1718 icmph->type != ICMP_PARAMETERPROB) { 1719 goto standard_hash; 1720 } 1721 1722 inner_iph = skb_header_pointer(skb, 1723 outer_iph->ihl * 4 + sizeof(_icmph), 1724 sizeof(_inner_iph), &_inner_iph); 1725 if (!inner_iph) 1726 goto standard_hash; 1727 1728 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr); 1729 1730 standard_hash: 1731 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr); 1732 } 1733 1734 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1735 1736 static int ip_mkroute_input(struct sk_buff *skb, 1737 struct fib_result *res, 1738 const struct flowi4 *fl4, 1739 struct in_device *in_dev, 1740 __be32 daddr, __be32 saddr, u32 tos) 1741 { 1742 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1743 if (res->fi && res->fi->fib_nhs > 1) { 1744 int h; 1745 1746 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP)) 1747 h = ip_multipath_icmp_hash(skb); 1748 else 1749 h = fib_multipath_hash(saddr, daddr); 1750 fib_select_multipath(res, h); 1751 } 1752 #endif 1753 1754 /* create a routing cache entry */ 1755 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1756 } 1757 1758 /* 1759 * NOTE. We drop all the packets that has local source 1760 * addresses, because every properly looped back packet 1761 * must have correct destination already attached by output routine. 1762 * 1763 * Such approach solves two big problems: 1764 * 1. Not simplex devices are handled properly. 1765 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1766 * called with rcu_read_lock() 1767 */ 1768 1769 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1770 u8 tos, struct net_device *dev) 1771 { 1772 struct fib_result res; 1773 struct in_device *in_dev = __in_dev_get_rcu(dev); 1774 struct ip_tunnel_info *tun_info; 1775 struct flowi4 fl4; 1776 unsigned int flags = 0; 1777 u32 itag = 0; 1778 struct rtable *rth; 1779 int err = -EINVAL; 1780 struct net *net = dev_net(dev); 1781 bool do_cache; 1782 1783 /* IP on this device is disabled. */ 1784 1785 if (!in_dev) 1786 goto out; 1787 1788 /* Check for the most weird martians, which can be not detected 1789 by fib_lookup. 1790 */ 1791 1792 tun_info = skb_tunnel_info(skb); 1793 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1794 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1795 else 1796 fl4.flowi4_tun_key.tun_id = 0; 1797 skb_dst_drop(skb); 1798 1799 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1800 goto martian_source; 1801 1802 res.fi = NULL; 1803 res.table = NULL; 1804 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1805 goto brd_input; 1806 1807 /* Accept zero addresses only to limited broadcast; 1808 * I even do not know to fix it or not. Waiting for complains :-) 1809 */ 1810 if (ipv4_is_zeronet(saddr)) 1811 goto martian_source; 1812 1813 if (ipv4_is_zeronet(daddr)) 1814 goto martian_destination; 1815 1816 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1817 * and call it once if daddr or/and saddr are loopback addresses 1818 */ 1819 if (ipv4_is_loopback(daddr)) { 1820 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1821 goto martian_destination; 1822 } else if (ipv4_is_loopback(saddr)) { 1823 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1824 goto martian_source; 1825 } 1826 1827 /* 1828 * Now we are ready to route packet. 1829 */ 1830 fl4.flowi4_oif = 0; 1831 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev); 1832 fl4.flowi4_mark = skb->mark; 1833 fl4.flowi4_tos = tos; 1834 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1835 fl4.flowi4_flags = 0; 1836 fl4.daddr = daddr; 1837 fl4.saddr = saddr; 1838 err = fib_lookup(net, &fl4, &res, 0); 1839 if (err != 0) { 1840 if (!IN_DEV_FORWARD(in_dev)) 1841 err = -EHOSTUNREACH; 1842 goto no_route; 1843 } 1844 1845 if (res.type == RTN_BROADCAST) 1846 goto brd_input; 1847 1848 if (res.type == RTN_LOCAL) { 1849 err = fib_validate_source(skb, saddr, daddr, tos, 1850 0, dev, in_dev, &itag); 1851 if (err < 0) 1852 goto martian_source; 1853 goto local_input; 1854 } 1855 1856 if (!IN_DEV_FORWARD(in_dev)) { 1857 err = -EHOSTUNREACH; 1858 goto no_route; 1859 } 1860 if (res.type != RTN_UNICAST) 1861 goto martian_destination; 1862 1863 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); 1864 out: return err; 1865 1866 brd_input: 1867 if (skb->protocol != htons(ETH_P_IP)) 1868 goto e_inval; 1869 1870 if (!ipv4_is_zeronet(saddr)) { 1871 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1872 in_dev, &itag); 1873 if (err < 0) 1874 goto martian_source; 1875 } 1876 flags |= RTCF_BROADCAST; 1877 res.type = RTN_BROADCAST; 1878 RT_CACHE_STAT_INC(in_brd); 1879 1880 local_input: 1881 do_cache = false; 1882 if (res.fi) { 1883 if (!itag) { 1884 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input); 1885 if (rt_cache_valid(rth)) { 1886 skb_dst_set_noref(skb, &rth->dst); 1887 err = 0; 1888 goto out; 1889 } 1890 do_cache = true; 1891 } 1892 } 1893 1894 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type, 1895 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 1896 if (!rth) 1897 goto e_nobufs; 1898 1899 rth->dst.output= ip_rt_bug; 1900 #ifdef CONFIG_IP_ROUTE_CLASSID 1901 rth->dst.tclassid = itag; 1902 #endif 1903 rth->rt_is_input = 1; 1904 if (res.table) 1905 rth->rt_table_id = res.table->tb_id; 1906 1907 RT_CACHE_STAT_INC(in_slow_tot); 1908 if (res.type == RTN_UNREACHABLE) { 1909 rth->dst.input= ip_error; 1910 rth->dst.error= -err; 1911 rth->rt_flags &= ~RTCF_LOCAL; 1912 } 1913 if (do_cache) { 1914 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) { 1915 rth->dst.flags |= DST_NOCACHE; 1916 rt_add_uncached_list(rth); 1917 } 1918 } 1919 skb_dst_set(skb, &rth->dst); 1920 err = 0; 1921 goto out; 1922 1923 no_route: 1924 RT_CACHE_STAT_INC(in_no_route); 1925 res.type = RTN_UNREACHABLE; 1926 res.fi = NULL; 1927 res.table = NULL; 1928 goto local_input; 1929 1930 /* 1931 * Do not cache martian addresses: they should be logged (RFC1812) 1932 */ 1933 martian_destination: 1934 RT_CACHE_STAT_INC(in_martian_dst); 1935 #ifdef CONFIG_IP_ROUTE_VERBOSE 1936 if (IN_DEV_LOG_MARTIANS(in_dev)) 1937 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 1938 &daddr, &saddr, dev->name); 1939 #endif 1940 1941 e_inval: 1942 err = -EINVAL; 1943 goto out; 1944 1945 e_nobufs: 1946 err = -ENOBUFS; 1947 goto out; 1948 1949 martian_source: 1950 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 1951 goto out; 1952 } 1953 1954 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1955 u8 tos, struct net_device *dev) 1956 { 1957 int res; 1958 1959 rcu_read_lock(); 1960 1961 /* Multicast recognition logic is moved from route cache to here. 1962 The problem was that too many Ethernet cards have broken/missing 1963 hardware multicast filters :-( As result the host on multicasting 1964 network acquires a lot of useless route cache entries, sort of 1965 SDR messages from all the world. Now we try to get rid of them. 1966 Really, provided software IP multicast filter is organized 1967 reasonably (at least, hashed), it does not result in a slowdown 1968 comparing with route cache reject entries. 1969 Note, that multicast routers are not affected, because 1970 route cache entry is created eventually. 1971 */ 1972 if (ipv4_is_multicast(daddr)) { 1973 struct in_device *in_dev = __in_dev_get_rcu(dev); 1974 1975 if (in_dev) { 1976 int our = ip_check_mc_rcu(in_dev, daddr, saddr, 1977 ip_hdr(skb)->protocol); 1978 if (our 1979 #ifdef CONFIG_IP_MROUTE 1980 || 1981 (!ipv4_is_local_multicast(daddr) && 1982 IN_DEV_MFORWARD(in_dev)) 1983 #endif 1984 ) { 1985 int res = ip_route_input_mc(skb, daddr, saddr, 1986 tos, dev, our); 1987 rcu_read_unlock(); 1988 return res; 1989 } 1990 } 1991 rcu_read_unlock(); 1992 return -EINVAL; 1993 } 1994 res = ip_route_input_slow(skb, daddr, saddr, tos, dev); 1995 rcu_read_unlock(); 1996 return res; 1997 } 1998 EXPORT_SYMBOL(ip_route_input_noref); 1999 2000 /* called with rcu_read_lock() */ 2001 static struct rtable *__mkroute_output(const struct fib_result *res, 2002 const struct flowi4 *fl4, int orig_oif, 2003 struct net_device *dev_out, 2004 unsigned int flags) 2005 { 2006 struct fib_info *fi = res->fi; 2007 struct fib_nh_exception *fnhe; 2008 struct in_device *in_dev; 2009 u16 type = res->type; 2010 struct rtable *rth; 2011 bool do_cache; 2012 2013 in_dev = __in_dev_get_rcu(dev_out); 2014 if (!in_dev) 2015 return ERR_PTR(-EINVAL); 2016 2017 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2018 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK)) 2019 return ERR_PTR(-EINVAL); 2020 2021 if (ipv4_is_lbcast(fl4->daddr)) 2022 type = RTN_BROADCAST; 2023 else if (ipv4_is_multicast(fl4->daddr)) 2024 type = RTN_MULTICAST; 2025 else if (ipv4_is_zeronet(fl4->daddr)) 2026 return ERR_PTR(-EINVAL); 2027 2028 if (dev_out->flags & IFF_LOOPBACK) 2029 flags |= RTCF_LOCAL; 2030 2031 do_cache = true; 2032 if (type == RTN_BROADCAST) { 2033 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2034 fi = NULL; 2035 } else if (type == RTN_MULTICAST) { 2036 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2037 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2038 fl4->flowi4_proto)) 2039 flags &= ~RTCF_LOCAL; 2040 else 2041 do_cache = false; 2042 /* If multicast route do not exist use 2043 * default one, but do not gateway in this case. 2044 * Yes, it is hack. 2045 */ 2046 if (fi && res->prefixlen < 4) 2047 fi = NULL; 2048 } 2049 2050 fnhe = NULL; 2051 do_cache &= fi != NULL; 2052 if (do_cache) { 2053 struct rtable __rcu **prth; 2054 struct fib_nh *nh = &FIB_RES_NH(*res); 2055 2056 fnhe = find_exception(nh, fl4->daddr); 2057 if (fnhe) { 2058 prth = &fnhe->fnhe_rth_output; 2059 rth = rcu_dereference(*prth); 2060 if (rth && rth->dst.expires && 2061 time_after(jiffies, rth->dst.expires)) { 2062 ip_del_fnhe(nh, fl4->daddr); 2063 fnhe = NULL; 2064 } else { 2065 goto rt_cache; 2066 } 2067 } 2068 2069 if (unlikely(fl4->flowi4_flags & 2070 FLOWI_FLAG_KNOWN_NH && 2071 !(nh->nh_gw && 2072 nh->nh_scope == RT_SCOPE_LINK))) { 2073 do_cache = false; 2074 goto add; 2075 } 2076 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2077 rth = rcu_dereference(*prth); 2078 2079 rt_cache: 2080 if (rt_cache_valid(rth)) { 2081 dst_hold(&rth->dst); 2082 return rth; 2083 } 2084 } 2085 2086 add: 2087 rth = rt_dst_alloc(dev_out, flags, type, 2088 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2089 IN_DEV_CONF_GET(in_dev, NOXFRM), 2090 do_cache); 2091 if (!rth) 2092 return ERR_PTR(-ENOBUFS); 2093 2094 rth->rt_iif = orig_oif ? : 0; 2095 if (res->table) 2096 rth->rt_table_id = res->table->tb_id; 2097 2098 RT_CACHE_STAT_INC(out_slow_tot); 2099 2100 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2101 if (flags & RTCF_LOCAL && 2102 !(dev_out->flags & IFF_LOOPBACK)) { 2103 rth->dst.output = ip_mc_output; 2104 RT_CACHE_STAT_INC(out_slow_mc); 2105 } 2106 #ifdef CONFIG_IP_MROUTE 2107 if (type == RTN_MULTICAST) { 2108 if (IN_DEV_MFORWARD(in_dev) && 2109 !ipv4_is_local_multicast(fl4->daddr)) { 2110 rth->dst.input = ip_mr_input; 2111 rth->dst.output = ip_mc_output; 2112 } 2113 } 2114 #endif 2115 } 2116 2117 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0); 2118 if (lwtunnel_output_redirect(rth->dst.lwtstate)) 2119 rth->dst.output = lwtunnel_output; 2120 2121 return rth; 2122 } 2123 2124 /* 2125 * Major route resolver routine. 2126 */ 2127 2128 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2129 int mp_hash) 2130 { 2131 struct net_device *dev_out = NULL; 2132 __u8 tos = RT_FL_TOS(fl4); 2133 unsigned int flags = 0; 2134 struct fib_result res; 2135 struct rtable *rth; 2136 int orig_oif; 2137 int err = -ENETUNREACH; 2138 2139 res.tclassid = 0; 2140 res.fi = NULL; 2141 res.table = NULL; 2142 2143 orig_oif = fl4->flowi4_oif; 2144 2145 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2146 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2147 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2148 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2149 2150 rcu_read_lock(); 2151 if (fl4->saddr) { 2152 rth = ERR_PTR(-EINVAL); 2153 if (ipv4_is_multicast(fl4->saddr) || 2154 ipv4_is_lbcast(fl4->saddr) || 2155 ipv4_is_zeronet(fl4->saddr)) 2156 goto out; 2157 2158 /* I removed check for oif == dev_out->oif here. 2159 It was wrong for two reasons: 2160 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2161 is assigned to multiple interfaces. 2162 2. Moreover, we are allowed to send packets with saddr 2163 of another iface. --ANK 2164 */ 2165 2166 if (fl4->flowi4_oif == 0 && 2167 (ipv4_is_multicast(fl4->daddr) || 2168 ipv4_is_lbcast(fl4->daddr))) { 2169 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2170 dev_out = __ip_dev_find(net, fl4->saddr, false); 2171 if (!dev_out) 2172 goto out; 2173 2174 /* Special hack: user can direct multicasts 2175 and limited broadcast via necessary interface 2176 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2177 This hack is not just for fun, it allows 2178 vic,vat and friends to work. 2179 They bind socket to loopback, set ttl to zero 2180 and expect that it will work. 2181 From the viewpoint of routing cache they are broken, 2182 because we are not allowed to build multicast path 2183 with loopback source addr (look, routing cache 2184 cannot know, that ttl is zero, so that packet 2185 will not leave this host and route is valid). 2186 Luckily, this hack is good workaround. 2187 */ 2188 2189 fl4->flowi4_oif = dev_out->ifindex; 2190 goto make_route; 2191 } 2192 2193 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2194 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2195 if (!__ip_dev_find(net, fl4->saddr, false)) 2196 goto out; 2197 } 2198 } 2199 2200 2201 if (fl4->flowi4_oif) { 2202 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2203 rth = ERR_PTR(-ENODEV); 2204 if (!dev_out) 2205 goto out; 2206 2207 /* RACE: Check return value of inet_select_addr instead. */ 2208 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2209 rth = ERR_PTR(-ENETUNREACH); 2210 goto out; 2211 } 2212 if (ipv4_is_local_multicast(fl4->daddr) || 2213 ipv4_is_lbcast(fl4->daddr) || 2214 fl4->flowi4_proto == IPPROTO_IGMP) { 2215 if (!fl4->saddr) 2216 fl4->saddr = inet_select_addr(dev_out, 0, 2217 RT_SCOPE_LINK); 2218 goto make_route; 2219 } 2220 if (!fl4->saddr) { 2221 if (ipv4_is_multicast(fl4->daddr)) 2222 fl4->saddr = inet_select_addr(dev_out, 0, 2223 fl4->flowi4_scope); 2224 else if (!fl4->daddr) 2225 fl4->saddr = inet_select_addr(dev_out, 0, 2226 RT_SCOPE_HOST); 2227 } 2228 2229 rth = l3mdev_get_rtable(dev_out, fl4); 2230 if (rth) 2231 goto out; 2232 } 2233 2234 if (!fl4->daddr) { 2235 fl4->daddr = fl4->saddr; 2236 if (!fl4->daddr) 2237 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2238 dev_out = net->loopback_dev; 2239 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2240 res.type = RTN_LOCAL; 2241 flags |= RTCF_LOCAL; 2242 goto make_route; 2243 } 2244 2245 err = fib_lookup(net, fl4, &res, 0); 2246 if (err) { 2247 res.fi = NULL; 2248 res.table = NULL; 2249 if (fl4->flowi4_oif && 2250 !netif_index_is_l3_master(net, fl4->flowi4_oif)) { 2251 /* Apparently, routing tables are wrong. Assume, 2252 that the destination is on link. 2253 2254 WHY? DW. 2255 Because we are allowed to send to iface 2256 even if it has NO routes and NO assigned 2257 addresses. When oif is specified, routing 2258 tables are looked up with only one purpose: 2259 to catch if destination is gatewayed, rather than 2260 direct. Moreover, if MSG_DONTROUTE is set, 2261 we send packet, ignoring both routing tables 2262 and ifaddr state. --ANK 2263 2264 2265 We could make it even if oif is unknown, 2266 likely IPv6, but we do not. 2267 */ 2268 2269 if (fl4->saddr == 0) 2270 fl4->saddr = inet_select_addr(dev_out, 0, 2271 RT_SCOPE_LINK); 2272 res.type = RTN_UNICAST; 2273 goto make_route; 2274 } 2275 rth = ERR_PTR(err); 2276 goto out; 2277 } 2278 2279 if (res.type == RTN_LOCAL) { 2280 if (!fl4->saddr) { 2281 if (res.fi->fib_prefsrc) 2282 fl4->saddr = res.fi->fib_prefsrc; 2283 else 2284 fl4->saddr = fl4->daddr; 2285 } 2286 dev_out = net->loopback_dev; 2287 fl4->flowi4_oif = dev_out->ifindex; 2288 flags |= RTCF_LOCAL; 2289 goto make_route; 2290 } 2291 2292 fib_select_path(net, &res, fl4, mp_hash); 2293 2294 dev_out = FIB_RES_DEV(res); 2295 fl4->flowi4_oif = dev_out->ifindex; 2296 2297 2298 make_route: 2299 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags); 2300 2301 out: 2302 rcu_read_unlock(); 2303 return rth; 2304 } 2305 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash); 2306 2307 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2308 { 2309 return NULL; 2310 } 2311 2312 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2313 { 2314 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2315 2316 return mtu ? : dst->dev->mtu; 2317 } 2318 2319 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2320 struct sk_buff *skb, u32 mtu) 2321 { 2322 } 2323 2324 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2325 struct sk_buff *skb) 2326 { 2327 } 2328 2329 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2330 unsigned long old) 2331 { 2332 return NULL; 2333 } 2334 2335 static struct dst_ops ipv4_dst_blackhole_ops = { 2336 .family = AF_INET, 2337 .check = ipv4_blackhole_dst_check, 2338 .mtu = ipv4_blackhole_mtu, 2339 .default_advmss = ipv4_default_advmss, 2340 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2341 .redirect = ipv4_rt_blackhole_redirect, 2342 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2343 .neigh_lookup = ipv4_neigh_lookup, 2344 }; 2345 2346 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2347 { 2348 struct rtable *ort = (struct rtable *) dst_orig; 2349 struct rtable *rt; 2350 2351 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0); 2352 if (rt) { 2353 struct dst_entry *new = &rt->dst; 2354 2355 new->__use = 1; 2356 new->input = dst_discard; 2357 new->output = dst_discard_out; 2358 2359 new->dev = ort->dst.dev; 2360 if (new->dev) 2361 dev_hold(new->dev); 2362 2363 rt->rt_is_input = ort->rt_is_input; 2364 rt->rt_iif = ort->rt_iif; 2365 rt->rt_pmtu = ort->rt_pmtu; 2366 2367 rt->rt_genid = rt_genid_ipv4(net); 2368 rt->rt_flags = ort->rt_flags; 2369 rt->rt_type = ort->rt_type; 2370 rt->rt_gateway = ort->rt_gateway; 2371 rt->rt_uses_gateway = ort->rt_uses_gateway; 2372 2373 INIT_LIST_HEAD(&rt->rt_uncached); 2374 dst_free(new); 2375 } 2376 2377 dst_release(dst_orig); 2378 2379 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2380 } 2381 2382 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2383 const struct sock *sk) 2384 { 2385 struct rtable *rt = __ip_route_output_key(net, flp4); 2386 2387 if (IS_ERR(rt)) 2388 return rt; 2389 2390 if (flp4->flowi4_proto) 2391 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2392 flowi4_to_flowi(flp4), 2393 sk, 0); 2394 2395 return rt; 2396 } 2397 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2398 2399 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2400 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2401 u32 seq, int event, int nowait, unsigned int flags) 2402 { 2403 struct rtable *rt = skb_rtable(skb); 2404 struct rtmsg *r; 2405 struct nlmsghdr *nlh; 2406 unsigned long expires = 0; 2407 u32 error; 2408 u32 metrics[RTAX_MAX]; 2409 2410 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags); 2411 if (!nlh) 2412 return -EMSGSIZE; 2413 2414 r = nlmsg_data(nlh); 2415 r->rtm_family = AF_INET; 2416 r->rtm_dst_len = 32; 2417 r->rtm_src_len = 0; 2418 r->rtm_tos = fl4->flowi4_tos; 2419 r->rtm_table = table_id; 2420 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2421 goto nla_put_failure; 2422 r->rtm_type = rt->rt_type; 2423 r->rtm_scope = RT_SCOPE_UNIVERSE; 2424 r->rtm_protocol = RTPROT_UNSPEC; 2425 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2426 if (rt->rt_flags & RTCF_NOTIFY) 2427 r->rtm_flags |= RTM_F_NOTIFY; 2428 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2429 r->rtm_flags |= RTCF_DOREDIRECT; 2430 2431 if (nla_put_in_addr(skb, RTA_DST, dst)) 2432 goto nla_put_failure; 2433 if (src) { 2434 r->rtm_src_len = 32; 2435 if (nla_put_in_addr(skb, RTA_SRC, src)) 2436 goto nla_put_failure; 2437 } 2438 if (rt->dst.dev && 2439 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2440 goto nla_put_failure; 2441 #ifdef CONFIG_IP_ROUTE_CLASSID 2442 if (rt->dst.tclassid && 2443 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2444 goto nla_put_failure; 2445 #endif 2446 if (!rt_is_input_route(rt) && 2447 fl4->saddr != src) { 2448 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2449 goto nla_put_failure; 2450 } 2451 if (rt->rt_uses_gateway && 2452 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2453 goto nla_put_failure; 2454 2455 expires = rt->dst.expires; 2456 if (expires) { 2457 unsigned long now = jiffies; 2458 2459 if (time_before(now, expires)) 2460 expires -= now; 2461 else 2462 expires = 0; 2463 } 2464 2465 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2466 if (rt->rt_pmtu && expires) 2467 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2468 if (rtnetlink_put_metrics(skb, metrics) < 0) 2469 goto nla_put_failure; 2470 2471 if (fl4->flowi4_mark && 2472 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2473 goto nla_put_failure; 2474 2475 error = rt->dst.error; 2476 2477 if (rt_is_input_route(rt)) { 2478 #ifdef CONFIG_IP_MROUTE 2479 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2480 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2481 int err = ipmr_get_route(net, skb, 2482 fl4->saddr, fl4->daddr, 2483 r, nowait); 2484 if (err <= 0) { 2485 if (!nowait) { 2486 if (err == 0) 2487 return 0; 2488 goto nla_put_failure; 2489 } else { 2490 if (err == -EMSGSIZE) 2491 goto nla_put_failure; 2492 error = err; 2493 } 2494 } 2495 } else 2496 #endif 2497 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2498 goto nla_put_failure; 2499 } 2500 2501 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2502 goto nla_put_failure; 2503 2504 nlmsg_end(skb, nlh); 2505 return 0; 2506 2507 nla_put_failure: 2508 nlmsg_cancel(skb, nlh); 2509 return -EMSGSIZE; 2510 } 2511 2512 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh) 2513 { 2514 struct net *net = sock_net(in_skb->sk); 2515 struct rtmsg *rtm; 2516 struct nlattr *tb[RTA_MAX+1]; 2517 struct rtable *rt = NULL; 2518 struct flowi4 fl4; 2519 __be32 dst = 0; 2520 __be32 src = 0; 2521 u32 iif; 2522 int err; 2523 int mark; 2524 struct sk_buff *skb; 2525 u32 table_id = RT_TABLE_MAIN; 2526 2527 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 2528 if (err < 0) 2529 goto errout; 2530 2531 rtm = nlmsg_data(nlh); 2532 2533 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2534 if (!skb) { 2535 err = -ENOBUFS; 2536 goto errout; 2537 } 2538 2539 /* Reserve room for dummy headers, this skb can pass 2540 through good chunk of routing engine. 2541 */ 2542 skb_reset_mac_header(skb); 2543 skb_reset_network_header(skb); 2544 2545 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 2546 ip_hdr(skb)->protocol = IPPROTO_ICMP; 2547 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2548 2549 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2550 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2551 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2552 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2553 2554 memset(&fl4, 0, sizeof(fl4)); 2555 fl4.daddr = dst; 2556 fl4.saddr = src; 2557 fl4.flowi4_tos = rtm->rtm_tos; 2558 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2559 fl4.flowi4_mark = mark; 2560 2561 if (netif_index_is_l3_master(net, fl4.flowi4_oif)) 2562 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF; 2563 2564 if (iif) { 2565 struct net_device *dev; 2566 2567 dev = __dev_get_by_index(net, iif); 2568 if (!dev) { 2569 err = -ENODEV; 2570 goto errout_free; 2571 } 2572 2573 skb->protocol = htons(ETH_P_IP); 2574 skb->dev = dev; 2575 skb->mark = mark; 2576 local_bh_disable(); 2577 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 2578 local_bh_enable(); 2579 2580 rt = skb_rtable(skb); 2581 if (err == 0 && rt->dst.error) 2582 err = -rt->dst.error; 2583 } else { 2584 rt = ip_route_output_key(net, &fl4); 2585 2586 err = 0; 2587 if (IS_ERR(rt)) 2588 err = PTR_ERR(rt); 2589 } 2590 2591 if (err) 2592 goto errout_free; 2593 2594 skb_dst_set(skb, &rt->dst); 2595 if (rtm->rtm_flags & RTM_F_NOTIFY) 2596 rt->rt_flags |= RTCF_NOTIFY; 2597 2598 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2599 table_id = rt->rt_table_id; 2600 2601 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2602 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2603 RTM_NEWROUTE, 0, 0); 2604 if (err < 0) 2605 goto errout_free; 2606 2607 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2608 errout: 2609 return err; 2610 2611 errout_free: 2612 kfree_skb(skb); 2613 goto errout; 2614 } 2615 2616 void ip_rt_multicast_event(struct in_device *in_dev) 2617 { 2618 rt_cache_flush(dev_net(in_dev->dev)); 2619 } 2620 2621 #ifdef CONFIG_SYSCTL 2622 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2623 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2624 static int ip_rt_gc_elasticity __read_mostly = 8; 2625 2626 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2627 void __user *buffer, 2628 size_t *lenp, loff_t *ppos) 2629 { 2630 struct net *net = (struct net *)__ctl->extra1; 2631 2632 if (write) { 2633 rt_cache_flush(net); 2634 fnhe_genid_bump(net); 2635 return 0; 2636 } 2637 2638 return -EINVAL; 2639 } 2640 2641 static struct ctl_table ipv4_route_table[] = { 2642 { 2643 .procname = "gc_thresh", 2644 .data = &ipv4_dst_ops.gc_thresh, 2645 .maxlen = sizeof(int), 2646 .mode = 0644, 2647 .proc_handler = proc_dointvec, 2648 }, 2649 { 2650 .procname = "max_size", 2651 .data = &ip_rt_max_size, 2652 .maxlen = sizeof(int), 2653 .mode = 0644, 2654 .proc_handler = proc_dointvec, 2655 }, 2656 { 2657 /* Deprecated. Use gc_min_interval_ms */ 2658 2659 .procname = "gc_min_interval", 2660 .data = &ip_rt_gc_min_interval, 2661 .maxlen = sizeof(int), 2662 .mode = 0644, 2663 .proc_handler = proc_dointvec_jiffies, 2664 }, 2665 { 2666 .procname = "gc_min_interval_ms", 2667 .data = &ip_rt_gc_min_interval, 2668 .maxlen = sizeof(int), 2669 .mode = 0644, 2670 .proc_handler = proc_dointvec_ms_jiffies, 2671 }, 2672 { 2673 .procname = "gc_timeout", 2674 .data = &ip_rt_gc_timeout, 2675 .maxlen = sizeof(int), 2676 .mode = 0644, 2677 .proc_handler = proc_dointvec_jiffies, 2678 }, 2679 { 2680 .procname = "gc_interval", 2681 .data = &ip_rt_gc_interval, 2682 .maxlen = sizeof(int), 2683 .mode = 0644, 2684 .proc_handler = proc_dointvec_jiffies, 2685 }, 2686 { 2687 .procname = "redirect_load", 2688 .data = &ip_rt_redirect_load, 2689 .maxlen = sizeof(int), 2690 .mode = 0644, 2691 .proc_handler = proc_dointvec, 2692 }, 2693 { 2694 .procname = "redirect_number", 2695 .data = &ip_rt_redirect_number, 2696 .maxlen = sizeof(int), 2697 .mode = 0644, 2698 .proc_handler = proc_dointvec, 2699 }, 2700 { 2701 .procname = "redirect_silence", 2702 .data = &ip_rt_redirect_silence, 2703 .maxlen = sizeof(int), 2704 .mode = 0644, 2705 .proc_handler = proc_dointvec, 2706 }, 2707 { 2708 .procname = "error_cost", 2709 .data = &ip_rt_error_cost, 2710 .maxlen = sizeof(int), 2711 .mode = 0644, 2712 .proc_handler = proc_dointvec, 2713 }, 2714 { 2715 .procname = "error_burst", 2716 .data = &ip_rt_error_burst, 2717 .maxlen = sizeof(int), 2718 .mode = 0644, 2719 .proc_handler = proc_dointvec, 2720 }, 2721 { 2722 .procname = "gc_elasticity", 2723 .data = &ip_rt_gc_elasticity, 2724 .maxlen = sizeof(int), 2725 .mode = 0644, 2726 .proc_handler = proc_dointvec, 2727 }, 2728 { 2729 .procname = "mtu_expires", 2730 .data = &ip_rt_mtu_expires, 2731 .maxlen = sizeof(int), 2732 .mode = 0644, 2733 .proc_handler = proc_dointvec_jiffies, 2734 }, 2735 { 2736 .procname = "min_pmtu", 2737 .data = &ip_rt_min_pmtu, 2738 .maxlen = sizeof(int), 2739 .mode = 0644, 2740 .proc_handler = proc_dointvec, 2741 }, 2742 { 2743 .procname = "min_adv_mss", 2744 .data = &ip_rt_min_advmss, 2745 .maxlen = sizeof(int), 2746 .mode = 0644, 2747 .proc_handler = proc_dointvec, 2748 }, 2749 { } 2750 }; 2751 2752 static struct ctl_table ipv4_route_flush_table[] = { 2753 { 2754 .procname = "flush", 2755 .maxlen = sizeof(int), 2756 .mode = 0200, 2757 .proc_handler = ipv4_sysctl_rtcache_flush, 2758 }, 2759 { }, 2760 }; 2761 2762 static __net_init int sysctl_route_net_init(struct net *net) 2763 { 2764 struct ctl_table *tbl; 2765 2766 tbl = ipv4_route_flush_table; 2767 if (!net_eq(net, &init_net)) { 2768 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2769 if (!tbl) 2770 goto err_dup; 2771 2772 /* Don't export sysctls to unprivileged users */ 2773 if (net->user_ns != &init_user_ns) 2774 tbl[0].procname = NULL; 2775 } 2776 tbl[0].extra1 = net; 2777 2778 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2779 if (!net->ipv4.route_hdr) 2780 goto err_reg; 2781 return 0; 2782 2783 err_reg: 2784 if (tbl != ipv4_route_flush_table) 2785 kfree(tbl); 2786 err_dup: 2787 return -ENOMEM; 2788 } 2789 2790 static __net_exit void sysctl_route_net_exit(struct net *net) 2791 { 2792 struct ctl_table *tbl; 2793 2794 tbl = net->ipv4.route_hdr->ctl_table_arg; 2795 unregister_net_sysctl_table(net->ipv4.route_hdr); 2796 BUG_ON(tbl == ipv4_route_flush_table); 2797 kfree(tbl); 2798 } 2799 2800 static __net_initdata struct pernet_operations sysctl_route_ops = { 2801 .init = sysctl_route_net_init, 2802 .exit = sysctl_route_net_exit, 2803 }; 2804 #endif 2805 2806 static __net_init int rt_genid_init(struct net *net) 2807 { 2808 atomic_set(&net->ipv4.rt_genid, 0); 2809 atomic_set(&net->fnhe_genid, 0); 2810 get_random_bytes(&net->ipv4.dev_addr_genid, 2811 sizeof(net->ipv4.dev_addr_genid)); 2812 return 0; 2813 } 2814 2815 static __net_initdata struct pernet_operations rt_genid_ops = { 2816 .init = rt_genid_init, 2817 }; 2818 2819 static int __net_init ipv4_inetpeer_init(struct net *net) 2820 { 2821 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 2822 2823 if (!bp) 2824 return -ENOMEM; 2825 inet_peer_base_init(bp); 2826 net->ipv4.peers = bp; 2827 return 0; 2828 } 2829 2830 static void __net_exit ipv4_inetpeer_exit(struct net *net) 2831 { 2832 struct inet_peer_base *bp = net->ipv4.peers; 2833 2834 net->ipv4.peers = NULL; 2835 inetpeer_invalidate_tree(bp); 2836 kfree(bp); 2837 } 2838 2839 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 2840 .init = ipv4_inetpeer_init, 2841 .exit = ipv4_inetpeer_exit, 2842 }; 2843 2844 #ifdef CONFIG_IP_ROUTE_CLASSID 2845 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 2846 #endif /* CONFIG_IP_ROUTE_CLASSID */ 2847 2848 int __init ip_rt_init(void) 2849 { 2850 int rc = 0; 2851 int cpu; 2852 2853 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 2854 if (!ip_idents) 2855 panic("IP: failed to allocate ip_idents\n"); 2856 2857 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 2858 2859 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 2860 if (!ip_tstamps) 2861 panic("IP: failed to allocate ip_tstamps\n"); 2862 2863 for_each_possible_cpu(cpu) { 2864 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 2865 2866 INIT_LIST_HEAD(&ul->head); 2867 spin_lock_init(&ul->lock); 2868 } 2869 #ifdef CONFIG_IP_ROUTE_CLASSID 2870 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 2871 if (!ip_rt_acct) 2872 panic("IP: failed to allocate ip_rt_acct\n"); 2873 #endif 2874 2875 ipv4_dst_ops.kmem_cachep = 2876 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 2877 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2878 2879 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 2880 2881 if (dst_entries_init(&ipv4_dst_ops) < 0) 2882 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 2883 2884 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 2885 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 2886 2887 ipv4_dst_ops.gc_thresh = ~0; 2888 ip_rt_max_size = INT_MAX; 2889 2890 devinet_init(); 2891 ip_fib_init(); 2892 2893 if (ip_rt_proc_init()) 2894 pr_err("Unable to create route proc files\n"); 2895 #ifdef CONFIG_XFRM 2896 xfrm_init(); 2897 xfrm4_init(); 2898 #endif 2899 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); 2900 2901 #ifdef CONFIG_SYSCTL 2902 register_pernet_subsys(&sysctl_route_ops); 2903 #endif 2904 register_pernet_subsys(&rt_genid_ops); 2905 register_pernet_subsys(&ipv4_inetpeer_ops); 2906 return rc; 2907 } 2908 2909 #ifdef CONFIG_SYSCTL 2910 /* 2911 * We really need to sanitize the damn ipv4 init order, then all 2912 * this nonsense will go away. 2913 */ 2914 void __init ip_static_sysctl_init(void) 2915 { 2916 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 2917 } 2918 #endif 2919