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(net, IPSTATS_MIB_INADDRERRORS); 919 break; 920 921 case ENETUNREACH: 922 __IP_INC_STATS(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(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 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 EXPORT_SYMBOL(rt_dst_alloc); 1472 1473 /* called in rcu_read_lock() section */ 1474 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1475 u8 tos, struct net_device *dev, int our) 1476 { 1477 struct rtable *rth; 1478 struct in_device *in_dev = __in_dev_get_rcu(dev); 1479 unsigned int flags = RTCF_MULTICAST; 1480 u32 itag = 0; 1481 int err; 1482 1483 /* Primary sanity checks. */ 1484 1485 if (!in_dev) 1486 return -EINVAL; 1487 1488 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1489 skb->protocol != htons(ETH_P_IP)) 1490 goto e_inval; 1491 1492 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1493 goto e_inval; 1494 1495 if (ipv4_is_zeronet(saddr)) { 1496 if (!ipv4_is_local_multicast(daddr)) 1497 goto e_inval; 1498 } else { 1499 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1500 in_dev, &itag); 1501 if (err < 0) 1502 goto e_err; 1503 } 1504 if (our) 1505 flags |= RTCF_LOCAL; 1506 1507 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1508 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1509 if (!rth) 1510 goto e_nobufs; 1511 1512 #ifdef CONFIG_IP_ROUTE_CLASSID 1513 rth->dst.tclassid = itag; 1514 #endif 1515 rth->dst.output = ip_rt_bug; 1516 rth->rt_is_input= 1; 1517 1518 #ifdef CONFIG_IP_MROUTE 1519 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1520 rth->dst.input = ip_mr_input; 1521 #endif 1522 RT_CACHE_STAT_INC(in_slow_mc); 1523 1524 skb_dst_set(skb, &rth->dst); 1525 return 0; 1526 1527 e_nobufs: 1528 return -ENOBUFS; 1529 e_inval: 1530 return -EINVAL; 1531 e_err: 1532 return err; 1533 } 1534 1535 1536 static void ip_handle_martian_source(struct net_device *dev, 1537 struct in_device *in_dev, 1538 struct sk_buff *skb, 1539 __be32 daddr, 1540 __be32 saddr) 1541 { 1542 RT_CACHE_STAT_INC(in_martian_src); 1543 #ifdef CONFIG_IP_ROUTE_VERBOSE 1544 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1545 /* 1546 * RFC1812 recommendation, if source is martian, 1547 * the only hint is MAC header. 1548 */ 1549 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1550 &daddr, &saddr, dev->name); 1551 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1552 print_hex_dump(KERN_WARNING, "ll header: ", 1553 DUMP_PREFIX_OFFSET, 16, 1, 1554 skb_mac_header(skb), 1555 dev->hard_header_len, true); 1556 } 1557 } 1558 #endif 1559 } 1560 1561 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1562 { 1563 struct fnhe_hash_bucket *hash; 1564 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1565 u32 hval = fnhe_hashfun(daddr); 1566 1567 spin_lock_bh(&fnhe_lock); 1568 1569 hash = rcu_dereference_protected(nh->nh_exceptions, 1570 lockdep_is_held(&fnhe_lock)); 1571 hash += hval; 1572 1573 fnhe_p = &hash->chain; 1574 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1575 while (fnhe) { 1576 if (fnhe->fnhe_daddr == daddr) { 1577 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1578 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1579 fnhe_flush_routes(fnhe); 1580 kfree_rcu(fnhe, rcu); 1581 break; 1582 } 1583 fnhe_p = &fnhe->fnhe_next; 1584 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1585 lockdep_is_held(&fnhe_lock)); 1586 } 1587 1588 spin_unlock_bh(&fnhe_lock); 1589 } 1590 1591 /* called in rcu_read_lock() section */ 1592 static int __mkroute_input(struct sk_buff *skb, 1593 const struct fib_result *res, 1594 struct in_device *in_dev, 1595 __be32 daddr, __be32 saddr, u32 tos) 1596 { 1597 struct fib_nh_exception *fnhe; 1598 struct rtable *rth; 1599 int err; 1600 struct in_device *out_dev; 1601 bool do_cache; 1602 u32 itag = 0; 1603 1604 /* get a working reference to the output device */ 1605 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1606 if (!out_dev) { 1607 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1608 return -EINVAL; 1609 } 1610 1611 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1612 in_dev->dev, in_dev, &itag); 1613 if (err < 0) { 1614 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1615 saddr); 1616 1617 goto cleanup; 1618 } 1619 1620 do_cache = res->fi && !itag; 1621 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1622 skb->protocol == htons(ETH_P_IP) && 1623 (IN_DEV_SHARED_MEDIA(out_dev) || 1624 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1625 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1626 1627 if (skb->protocol != htons(ETH_P_IP)) { 1628 /* Not IP (i.e. ARP). Do not create route, if it is 1629 * invalid for proxy arp. DNAT routes are always valid. 1630 * 1631 * Proxy arp feature have been extended to allow, ARP 1632 * replies back to the same interface, to support 1633 * Private VLAN switch technologies. See arp.c. 1634 */ 1635 if (out_dev == in_dev && 1636 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1637 err = -EINVAL; 1638 goto cleanup; 1639 } 1640 } 1641 1642 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1643 if (do_cache) { 1644 if (fnhe) { 1645 rth = rcu_dereference(fnhe->fnhe_rth_input); 1646 if (rth && rth->dst.expires && 1647 time_after(jiffies, rth->dst.expires)) { 1648 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1649 fnhe = NULL; 1650 } else { 1651 goto rt_cache; 1652 } 1653 } 1654 1655 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1656 1657 rt_cache: 1658 if (rt_cache_valid(rth)) { 1659 skb_dst_set_noref(skb, &rth->dst); 1660 goto out; 1661 } 1662 } 1663 1664 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1665 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1666 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1667 if (!rth) { 1668 err = -ENOBUFS; 1669 goto cleanup; 1670 } 1671 1672 rth->rt_is_input = 1; 1673 if (res->table) 1674 rth->rt_table_id = res->table->tb_id; 1675 RT_CACHE_STAT_INC(in_slow_tot); 1676 1677 rth->dst.input = ip_forward; 1678 1679 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag); 1680 if (lwtunnel_output_redirect(rth->dst.lwtstate)) { 1681 rth->dst.lwtstate->orig_output = rth->dst.output; 1682 rth->dst.output = lwtunnel_output; 1683 } 1684 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 1685 rth->dst.lwtstate->orig_input = rth->dst.input; 1686 rth->dst.input = lwtunnel_input; 1687 } 1688 skb_dst_set(skb, &rth->dst); 1689 out: 1690 err = 0; 1691 cleanup: 1692 return err; 1693 } 1694 1695 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1696 1697 /* To make ICMP packets follow the right flow, the multipath hash is 1698 * calculated from the inner IP addresses in reverse order. 1699 */ 1700 static int ip_multipath_icmp_hash(struct sk_buff *skb) 1701 { 1702 const struct iphdr *outer_iph = ip_hdr(skb); 1703 struct icmphdr _icmph; 1704 const struct icmphdr *icmph; 1705 struct iphdr _inner_iph; 1706 const struct iphdr *inner_iph; 1707 1708 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1709 goto standard_hash; 1710 1711 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1712 &_icmph); 1713 if (!icmph) 1714 goto standard_hash; 1715 1716 if (icmph->type != ICMP_DEST_UNREACH && 1717 icmph->type != ICMP_REDIRECT && 1718 icmph->type != ICMP_TIME_EXCEEDED && 1719 icmph->type != ICMP_PARAMETERPROB) { 1720 goto standard_hash; 1721 } 1722 1723 inner_iph = skb_header_pointer(skb, 1724 outer_iph->ihl * 4 + sizeof(_icmph), 1725 sizeof(_inner_iph), &_inner_iph); 1726 if (!inner_iph) 1727 goto standard_hash; 1728 1729 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr); 1730 1731 standard_hash: 1732 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr); 1733 } 1734 1735 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1736 1737 static int ip_mkroute_input(struct sk_buff *skb, 1738 struct fib_result *res, 1739 const struct flowi4 *fl4, 1740 struct in_device *in_dev, 1741 __be32 daddr, __be32 saddr, u32 tos) 1742 { 1743 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1744 if (res->fi && res->fi->fib_nhs > 1) { 1745 int h; 1746 1747 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP)) 1748 h = ip_multipath_icmp_hash(skb); 1749 else 1750 h = fib_multipath_hash(saddr, daddr); 1751 fib_select_multipath(res, h); 1752 } 1753 #endif 1754 1755 /* create a routing cache entry */ 1756 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1757 } 1758 1759 /* 1760 * NOTE. We drop all the packets that has local source 1761 * addresses, because every properly looped back packet 1762 * must have correct destination already attached by output routine. 1763 * 1764 * Such approach solves two big problems: 1765 * 1. Not simplex devices are handled properly. 1766 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1767 * called with rcu_read_lock() 1768 */ 1769 1770 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1771 u8 tos, struct net_device *dev) 1772 { 1773 struct fib_result res; 1774 struct in_device *in_dev = __in_dev_get_rcu(dev); 1775 struct ip_tunnel_info *tun_info; 1776 struct flowi4 fl4; 1777 unsigned int flags = 0; 1778 u32 itag = 0; 1779 struct rtable *rth; 1780 int err = -EINVAL; 1781 struct net *net = dev_net(dev); 1782 bool do_cache; 1783 1784 /* IP on this device is disabled. */ 1785 1786 if (!in_dev) 1787 goto out; 1788 1789 /* Check for the most weird martians, which can be not detected 1790 by fib_lookup. 1791 */ 1792 1793 tun_info = skb_tunnel_info(skb); 1794 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1795 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1796 else 1797 fl4.flowi4_tun_key.tun_id = 0; 1798 skb_dst_drop(skb); 1799 1800 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1801 goto martian_source; 1802 1803 res.fi = NULL; 1804 res.table = NULL; 1805 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1806 goto brd_input; 1807 1808 /* Accept zero addresses only to limited broadcast; 1809 * I even do not know to fix it or not. Waiting for complains :-) 1810 */ 1811 if (ipv4_is_zeronet(saddr)) 1812 goto martian_source; 1813 1814 if (ipv4_is_zeronet(daddr)) 1815 goto martian_destination; 1816 1817 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1818 * and call it once if daddr or/and saddr are loopback addresses 1819 */ 1820 if (ipv4_is_loopback(daddr)) { 1821 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1822 goto martian_destination; 1823 } else if (ipv4_is_loopback(saddr)) { 1824 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1825 goto martian_source; 1826 } 1827 1828 /* 1829 * Now we are ready to route packet. 1830 */ 1831 fl4.flowi4_oif = 0; 1832 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev); 1833 fl4.flowi4_mark = skb->mark; 1834 fl4.flowi4_tos = tos; 1835 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1836 fl4.flowi4_flags = 0; 1837 fl4.daddr = daddr; 1838 fl4.saddr = saddr; 1839 err = fib_lookup(net, &fl4, &res, 0); 1840 if (err != 0) { 1841 if (!IN_DEV_FORWARD(in_dev)) 1842 err = -EHOSTUNREACH; 1843 goto no_route; 1844 } 1845 1846 if (res.type == RTN_BROADCAST) 1847 goto brd_input; 1848 1849 if (res.type == RTN_LOCAL) { 1850 err = fib_validate_source(skb, saddr, daddr, tos, 1851 0, dev, in_dev, &itag); 1852 if (err < 0) 1853 goto martian_source; 1854 goto local_input; 1855 } 1856 1857 if (!IN_DEV_FORWARD(in_dev)) { 1858 err = -EHOSTUNREACH; 1859 goto no_route; 1860 } 1861 if (res.type != RTN_UNICAST) 1862 goto martian_destination; 1863 1864 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); 1865 out: return err; 1866 1867 brd_input: 1868 if (skb->protocol != htons(ETH_P_IP)) 1869 goto e_inval; 1870 1871 if (!ipv4_is_zeronet(saddr)) { 1872 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1873 in_dev, &itag); 1874 if (err < 0) 1875 goto martian_source; 1876 } 1877 flags |= RTCF_BROADCAST; 1878 res.type = RTN_BROADCAST; 1879 RT_CACHE_STAT_INC(in_brd); 1880 1881 local_input: 1882 do_cache = false; 1883 if (res.fi) { 1884 if (!itag) { 1885 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input); 1886 if (rt_cache_valid(rth)) { 1887 skb_dst_set_noref(skb, &rth->dst); 1888 err = 0; 1889 goto out; 1890 } 1891 do_cache = true; 1892 } 1893 } 1894 1895 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type, 1896 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 1897 if (!rth) 1898 goto e_nobufs; 1899 1900 rth->dst.output= ip_rt_bug; 1901 #ifdef CONFIG_IP_ROUTE_CLASSID 1902 rth->dst.tclassid = itag; 1903 #endif 1904 rth->rt_is_input = 1; 1905 if (res.table) 1906 rth->rt_table_id = res.table->tb_id; 1907 1908 RT_CACHE_STAT_INC(in_slow_tot); 1909 if (res.type == RTN_UNREACHABLE) { 1910 rth->dst.input= ip_error; 1911 rth->dst.error= -err; 1912 rth->rt_flags &= ~RTCF_LOCAL; 1913 } 1914 if (do_cache) { 1915 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) { 1916 rth->dst.flags |= DST_NOCACHE; 1917 rt_add_uncached_list(rth); 1918 } 1919 } 1920 skb_dst_set(skb, &rth->dst); 1921 err = 0; 1922 goto out; 1923 1924 no_route: 1925 RT_CACHE_STAT_INC(in_no_route); 1926 res.type = RTN_UNREACHABLE; 1927 res.fi = NULL; 1928 res.table = NULL; 1929 goto local_input; 1930 1931 /* 1932 * Do not cache martian addresses: they should be logged (RFC1812) 1933 */ 1934 martian_destination: 1935 RT_CACHE_STAT_INC(in_martian_dst); 1936 #ifdef CONFIG_IP_ROUTE_VERBOSE 1937 if (IN_DEV_LOG_MARTIANS(in_dev)) 1938 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 1939 &daddr, &saddr, dev->name); 1940 #endif 1941 1942 e_inval: 1943 err = -EINVAL; 1944 goto out; 1945 1946 e_nobufs: 1947 err = -ENOBUFS; 1948 goto out; 1949 1950 martian_source: 1951 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 1952 goto out; 1953 } 1954 1955 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1956 u8 tos, struct net_device *dev) 1957 { 1958 int res; 1959 1960 rcu_read_lock(); 1961 1962 /* Multicast recognition logic is moved from route cache to here. 1963 The problem was that too many Ethernet cards have broken/missing 1964 hardware multicast filters :-( As result the host on multicasting 1965 network acquires a lot of useless route cache entries, sort of 1966 SDR messages from all the world. Now we try to get rid of them. 1967 Really, provided software IP multicast filter is organized 1968 reasonably (at least, hashed), it does not result in a slowdown 1969 comparing with route cache reject entries. 1970 Note, that multicast routers are not affected, because 1971 route cache entry is created eventually. 1972 */ 1973 if (ipv4_is_multicast(daddr)) { 1974 struct in_device *in_dev = __in_dev_get_rcu(dev); 1975 1976 if (in_dev) { 1977 int our = ip_check_mc_rcu(in_dev, daddr, saddr, 1978 ip_hdr(skb)->protocol); 1979 if (our 1980 #ifdef CONFIG_IP_MROUTE 1981 || 1982 (!ipv4_is_local_multicast(daddr) && 1983 IN_DEV_MFORWARD(in_dev)) 1984 #endif 1985 ) { 1986 int res = ip_route_input_mc(skb, daddr, saddr, 1987 tos, dev, our); 1988 rcu_read_unlock(); 1989 return res; 1990 } 1991 } 1992 rcu_read_unlock(); 1993 return -EINVAL; 1994 } 1995 res = ip_route_input_slow(skb, daddr, saddr, tos, dev); 1996 rcu_read_unlock(); 1997 return res; 1998 } 1999 EXPORT_SYMBOL(ip_route_input_noref); 2000 2001 /* called with rcu_read_lock() */ 2002 static struct rtable *__mkroute_output(const struct fib_result *res, 2003 const struct flowi4 *fl4, int orig_oif, 2004 struct net_device *dev_out, 2005 unsigned int flags) 2006 { 2007 struct fib_info *fi = res->fi; 2008 struct fib_nh_exception *fnhe; 2009 struct in_device *in_dev; 2010 u16 type = res->type; 2011 struct rtable *rth; 2012 bool do_cache; 2013 2014 in_dev = __in_dev_get_rcu(dev_out); 2015 if (!in_dev) 2016 return ERR_PTR(-EINVAL); 2017 2018 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2019 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK)) 2020 return ERR_PTR(-EINVAL); 2021 2022 if (ipv4_is_lbcast(fl4->daddr)) 2023 type = RTN_BROADCAST; 2024 else if (ipv4_is_multicast(fl4->daddr)) 2025 type = RTN_MULTICAST; 2026 else if (ipv4_is_zeronet(fl4->daddr)) 2027 return ERR_PTR(-EINVAL); 2028 2029 if (dev_out->flags & IFF_LOOPBACK) 2030 flags |= RTCF_LOCAL; 2031 2032 do_cache = true; 2033 if (type == RTN_BROADCAST) { 2034 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2035 fi = NULL; 2036 } else if (type == RTN_MULTICAST) { 2037 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2038 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2039 fl4->flowi4_proto)) 2040 flags &= ~RTCF_LOCAL; 2041 else 2042 do_cache = false; 2043 /* If multicast route do not exist use 2044 * default one, but do not gateway in this case. 2045 * Yes, it is hack. 2046 */ 2047 if (fi && res->prefixlen < 4) 2048 fi = NULL; 2049 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2050 (orig_oif != dev_out->ifindex)) { 2051 /* For local routes that require a particular output interface 2052 * we do not want to cache the result. Caching the result 2053 * causes incorrect behaviour when there are multiple source 2054 * addresses on the interface, the end result being that if the 2055 * intended recipient is waiting on that interface for the 2056 * packet he won't receive it because it will be delivered on 2057 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2058 * be set to the loopback interface as well. 2059 */ 2060 fi = NULL; 2061 } 2062 2063 fnhe = NULL; 2064 do_cache &= fi != NULL; 2065 if (do_cache) { 2066 struct rtable __rcu **prth; 2067 struct fib_nh *nh = &FIB_RES_NH(*res); 2068 2069 fnhe = find_exception(nh, fl4->daddr); 2070 if (fnhe) { 2071 prth = &fnhe->fnhe_rth_output; 2072 rth = rcu_dereference(*prth); 2073 if (rth && rth->dst.expires && 2074 time_after(jiffies, rth->dst.expires)) { 2075 ip_del_fnhe(nh, fl4->daddr); 2076 fnhe = NULL; 2077 } else { 2078 goto rt_cache; 2079 } 2080 } 2081 2082 if (unlikely(fl4->flowi4_flags & 2083 FLOWI_FLAG_KNOWN_NH && 2084 !(nh->nh_gw && 2085 nh->nh_scope == RT_SCOPE_LINK))) { 2086 do_cache = false; 2087 goto add; 2088 } 2089 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2090 rth = rcu_dereference(*prth); 2091 2092 rt_cache: 2093 if (rt_cache_valid(rth)) { 2094 dst_hold(&rth->dst); 2095 return rth; 2096 } 2097 } 2098 2099 add: 2100 rth = rt_dst_alloc(dev_out, flags, type, 2101 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2102 IN_DEV_CONF_GET(in_dev, NOXFRM), 2103 do_cache); 2104 if (!rth) 2105 return ERR_PTR(-ENOBUFS); 2106 2107 rth->rt_iif = orig_oif ? : 0; 2108 if (res->table) 2109 rth->rt_table_id = res->table->tb_id; 2110 2111 RT_CACHE_STAT_INC(out_slow_tot); 2112 2113 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2114 if (flags & RTCF_LOCAL && 2115 !(dev_out->flags & IFF_LOOPBACK)) { 2116 rth->dst.output = ip_mc_output; 2117 RT_CACHE_STAT_INC(out_slow_mc); 2118 } 2119 #ifdef CONFIG_IP_MROUTE 2120 if (type == RTN_MULTICAST) { 2121 if (IN_DEV_MFORWARD(in_dev) && 2122 !ipv4_is_local_multicast(fl4->daddr)) { 2123 rth->dst.input = ip_mr_input; 2124 rth->dst.output = ip_mc_output; 2125 } 2126 } 2127 #endif 2128 } 2129 2130 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0); 2131 if (lwtunnel_output_redirect(rth->dst.lwtstate)) 2132 rth->dst.output = lwtunnel_output; 2133 2134 return rth; 2135 } 2136 2137 /* 2138 * Major route resolver routine. 2139 */ 2140 2141 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2142 int mp_hash) 2143 { 2144 struct net_device *dev_out = NULL; 2145 __u8 tos = RT_FL_TOS(fl4); 2146 unsigned int flags = 0; 2147 struct fib_result res; 2148 struct rtable *rth; 2149 int master_idx; 2150 int orig_oif; 2151 int err = -ENETUNREACH; 2152 2153 res.tclassid = 0; 2154 res.fi = NULL; 2155 res.table = NULL; 2156 2157 orig_oif = fl4->flowi4_oif; 2158 2159 master_idx = l3mdev_master_ifindex_by_index(net, fl4->flowi4_oif); 2160 if (master_idx) 2161 fl4->flowi4_oif = master_idx; 2162 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2163 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2164 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2165 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2166 2167 rcu_read_lock(); 2168 if (fl4->saddr) { 2169 rth = ERR_PTR(-EINVAL); 2170 if (ipv4_is_multicast(fl4->saddr) || 2171 ipv4_is_lbcast(fl4->saddr) || 2172 ipv4_is_zeronet(fl4->saddr)) 2173 goto out; 2174 2175 /* I removed check for oif == dev_out->oif here. 2176 It was wrong for two reasons: 2177 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2178 is assigned to multiple interfaces. 2179 2. Moreover, we are allowed to send packets with saddr 2180 of another iface. --ANK 2181 */ 2182 2183 if (fl4->flowi4_oif == 0 && 2184 (ipv4_is_multicast(fl4->daddr) || 2185 ipv4_is_lbcast(fl4->daddr))) { 2186 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2187 dev_out = __ip_dev_find(net, fl4->saddr, false); 2188 if (!dev_out) 2189 goto out; 2190 2191 /* Special hack: user can direct multicasts 2192 and limited broadcast via necessary interface 2193 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2194 This hack is not just for fun, it allows 2195 vic,vat and friends to work. 2196 They bind socket to loopback, set ttl to zero 2197 and expect that it will work. 2198 From the viewpoint of routing cache they are broken, 2199 because we are not allowed to build multicast path 2200 with loopback source addr (look, routing cache 2201 cannot know, that ttl is zero, so that packet 2202 will not leave this host and route is valid). 2203 Luckily, this hack is good workaround. 2204 */ 2205 2206 fl4->flowi4_oif = dev_out->ifindex; 2207 goto make_route; 2208 } 2209 2210 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2211 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2212 if (!__ip_dev_find(net, fl4->saddr, false)) 2213 goto out; 2214 } 2215 } 2216 2217 2218 if (fl4->flowi4_oif) { 2219 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2220 rth = ERR_PTR(-ENODEV); 2221 if (!dev_out) 2222 goto out; 2223 2224 /* RACE: Check return value of inet_select_addr instead. */ 2225 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2226 rth = ERR_PTR(-ENETUNREACH); 2227 goto out; 2228 } 2229 if (ipv4_is_local_multicast(fl4->daddr) || 2230 ipv4_is_lbcast(fl4->daddr) || 2231 fl4->flowi4_proto == IPPROTO_IGMP) { 2232 if (!fl4->saddr) 2233 fl4->saddr = inet_select_addr(dev_out, 0, 2234 RT_SCOPE_LINK); 2235 goto make_route; 2236 } 2237 if (!fl4->saddr) { 2238 if (ipv4_is_multicast(fl4->daddr)) 2239 fl4->saddr = inet_select_addr(dev_out, 0, 2240 fl4->flowi4_scope); 2241 else if (!fl4->daddr) 2242 fl4->saddr = inet_select_addr(dev_out, 0, 2243 RT_SCOPE_HOST); 2244 } 2245 2246 rth = l3mdev_get_rtable(dev_out, fl4); 2247 if (rth) 2248 goto out; 2249 } 2250 2251 if (!fl4->daddr) { 2252 fl4->daddr = fl4->saddr; 2253 if (!fl4->daddr) 2254 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2255 dev_out = net->loopback_dev; 2256 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2257 res.type = RTN_LOCAL; 2258 flags |= RTCF_LOCAL; 2259 goto make_route; 2260 } 2261 2262 err = fib_lookup(net, fl4, &res, 0); 2263 if (err) { 2264 res.fi = NULL; 2265 res.table = NULL; 2266 if (fl4->flowi4_oif && 2267 !netif_index_is_l3_master(net, fl4->flowi4_oif)) { 2268 /* Apparently, routing tables are wrong. Assume, 2269 that the destination is on link. 2270 2271 WHY? DW. 2272 Because we are allowed to send to iface 2273 even if it has NO routes and NO assigned 2274 addresses. When oif is specified, routing 2275 tables are looked up with only one purpose: 2276 to catch if destination is gatewayed, rather than 2277 direct. Moreover, if MSG_DONTROUTE is set, 2278 we send packet, ignoring both routing tables 2279 and ifaddr state. --ANK 2280 2281 2282 We could make it even if oif is unknown, 2283 likely IPv6, but we do not. 2284 */ 2285 2286 if (fl4->saddr == 0) 2287 fl4->saddr = inet_select_addr(dev_out, 0, 2288 RT_SCOPE_LINK); 2289 res.type = RTN_UNICAST; 2290 goto make_route; 2291 } 2292 rth = ERR_PTR(err); 2293 goto out; 2294 } 2295 2296 if (res.type == RTN_LOCAL) { 2297 if (!fl4->saddr) { 2298 if (res.fi->fib_prefsrc) 2299 fl4->saddr = res.fi->fib_prefsrc; 2300 else 2301 fl4->saddr = fl4->daddr; 2302 } 2303 dev_out = net->loopback_dev; 2304 fl4->flowi4_oif = dev_out->ifindex; 2305 flags |= RTCF_LOCAL; 2306 goto make_route; 2307 } 2308 2309 fib_select_path(net, &res, fl4, mp_hash); 2310 2311 dev_out = FIB_RES_DEV(res); 2312 fl4->flowi4_oif = dev_out->ifindex; 2313 2314 2315 make_route: 2316 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags); 2317 2318 out: 2319 rcu_read_unlock(); 2320 return rth; 2321 } 2322 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash); 2323 2324 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2325 { 2326 return NULL; 2327 } 2328 2329 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2330 { 2331 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2332 2333 return mtu ? : dst->dev->mtu; 2334 } 2335 2336 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2337 struct sk_buff *skb, u32 mtu) 2338 { 2339 } 2340 2341 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2342 struct sk_buff *skb) 2343 { 2344 } 2345 2346 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2347 unsigned long old) 2348 { 2349 return NULL; 2350 } 2351 2352 static struct dst_ops ipv4_dst_blackhole_ops = { 2353 .family = AF_INET, 2354 .check = ipv4_blackhole_dst_check, 2355 .mtu = ipv4_blackhole_mtu, 2356 .default_advmss = ipv4_default_advmss, 2357 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2358 .redirect = ipv4_rt_blackhole_redirect, 2359 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2360 .neigh_lookup = ipv4_neigh_lookup, 2361 }; 2362 2363 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2364 { 2365 struct rtable *ort = (struct rtable *) dst_orig; 2366 struct rtable *rt; 2367 2368 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0); 2369 if (rt) { 2370 struct dst_entry *new = &rt->dst; 2371 2372 new->__use = 1; 2373 new->input = dst_discard; 2374 new->output = dst_discard_out; 2375 2376 new->dev = ort->dst.dev; 2377 if (new->dev) 2378 dev_hold(new->dev); 2379 2380 rt->rt_is_input = ort->rt_is_input; 2381 rt->rt_iif = ort->rt_iif; 2382 rt->rt_pmtu = ort->rt_pmtu; 2383 2384 rt->rt_genid = rt_genid_ipv4(net); 2385 rt->rt_flags = ort->rt_flags; 2386 rt->rt_type = ort->rt_type; 2387 rt->rt_gateway = ort->rt_gateway; 2388 rt->rt_uses_gateway = ort->rt_uses_gateway; 2389 2390 INIT_LIST_HEAD(&rt->rt_uncached); 2391 dst_free(new); 2392 } 2393 2394 dst_release(dst_orig); 2395 2396 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2397 } 2398 2399 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2400 const struct sock *sk) 2401 { 2402 struct rtable *rt = __ip_route_output_key(net, flp4); 2403 2404 if (IS_ERR(rt)) 2405 return rt; 2406 2407 if (flp4->flowi4_proto) 2408 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2409 flowi4_to_flowi(flp4), 2410 sk, 0); 2411 2412 return rt; 2413 } 2414 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2415 2416 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2417 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2418 u32 seq, int event, int nowait, unsigned int flags) 2419 { 2420 struct rtable *rt = skb_rtable(skb); 2421 struct rtmsg *r; 2422 struct nlmsghdr *nlh; 2423 unsigned long expires = 0; 2424 u32 error; 2425 u32 metrics[RTAX_MAX]; 2426 2427 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags); 2428 if (!nlh) 2429 return -EMSGSIZE; 2430 2431 r = nlmsg_data(nlh); 2432 r->rtm_family = AF_INET; 2433 r->rtm_dst_len = 32; 2434 r->rtm_src_len = 0; 2435 r->rtm_tos = fl4->flowi4_tos; 2436 r->rtm_table = table_id; 2437 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2438 goto nla_put_failure; 2439 r->rtm_type = rt->rt_type; 2440 r->rtm_scope = RT_SCOPE_UNIVERSE; 2441 r->rtm_protocol = RTPROT_UNSPEC; 2442 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2443 if (rt->rt_flags & RTCF_NOTIFY) 2444 r->rtm_flags |= RTM_F_NOTIFY; 2445 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2446 r->rtm_flags |= RTCF_DOREDIRECT; 2447 2448 if (nla_put_in_addr(skb, RTA_DST, dst)) 2449 goto nla_put_failure; 2450 if (src) { 2451 r->rtm_src_len = 32; 2452 if (nla_put_in_addr(skb, RTA_SRC, src)) 2453 goto nla_put_failure; 2454 } 2455 if (rt->dst.dev && 2456 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2457 goto nla_put_failure; 2458 #ifdef CONFIG_IP_ROUTE_CLASSID 2459 if (rt->dst.tclassid && 2460 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2461 goto nla_put_failure; 2462 #endif 2463 if (!rt_is_input_route(rt) && 2464 fl4->saddr != src) { 2465 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2466 goto nla_put_failure; 2467 } 2468 if (rt->rt_uses_gateway && 2469 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2470 goto nla_put_failure; 2471 2472 expires = rt->dst.expires; 2473 if (expires) { 2474 unsigned long now = jiffies; 2475 2476 if (time_before(now, expires)) 2477 expires -= now; 2478 else 2479 expires = 0; 2480 } 2481 2482 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2483 if (rt->rt_pmtu && expires) 2484 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2485 if (rtnetlink_put_metrics(skb, metrics) < 0) 2486 goto nla_put_failure; 2487 2488 if (fl4->flowi4_mark && 2489 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2490 goto nla_put_failure; 2491 2492 error = rt->dst.error; 2493 2494 if (rt_is_input_route(rt)) { 2495 #ifdef CONFIG_IP_MROUTE 2496 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2497 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2498 int err = ipmr_get_route(net, skb, 2499 fl4->saddr, fl4->daddr, 2500 r, nowait); 2501 if (err <= 0) { 2502 if (!nowait) { 2503 if (err == 0) 2504 return 0; 2505 goto nla_put_failure; 2506 } else { 2507 if (err == -EMSGSIZE) 2508 goto nla_put_failure; 2509 error = err; 2510 } 2511 } 2512 } else 2513 #endif 2514 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2515 goto nla_put_failure; 2516 } 2517 2518 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2519 goto nla_put_failure; 2520 2521 nlmsg_end(skb, nlh); 2522 return 0; 2523 2524 nla_put_failure: 2525 nlmsg_cancel(skb, nlh); 2526 return -EMSGSIZE; 2527 } 2528 2529 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh) 2530 { 2531 struct net *net = sock_net(in_skb->sk); 2532 struct rtmsg *rtm; 2533 struct nlattr *tb[RTA_MAX+1]; 2534 struct rtable *rt = NULL; 2535 struct flowi4 fl4; 2536 __be32 dst = 0; 2537 __be32 src = 0; 2538 u32 iif; 2539 int err; 2540 int mark; 2541 struct sk_buff *skb; 2542 u32 table_id = RT_TABLE_MAIN; 2543 2544 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 2545 if (err < 0) 2546 goto errout; 2547 2548 rtm = nlmsg_data(nlh); 2549 2550 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2551 if (!skb) { 2552 err = -ENOBUFS; 2553 goto errout; 2554 } 2555 2556 /* Reserve room for dummy headers, this skb can pass 2557 through good chunk of routing engine. 2558 */ 2559 skb_reset_mac_header(skb); 2560 skb_reset_network_header(skb); 2561 2562 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 2563 ip_hdr(skb)->protocol = IPPROTO_ICMP; 2564 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2565 2566 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2567 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2568 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2569 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2570 2571 memset(&fl4, 0, sizeof(fl4)); 2572 fl4.daddr = dst; 2573 fl4.saddr = src; 2574 fl4.flowi4_tos = rtm->rtm_tos; 2575 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2576 fl4.flowi4_mark = mark; 2577 2578 if (netif_index_is_l3_master(net, fl4.flowi4_oif)) 2579 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF; 2580 2581 if (iif) { 2582 struct net_device *dev; 2583 2584 dev = __dev_get_by_index(net, iif); 2585 if (!dev) { 2586 err = -ENODEV; 2587 goto errout_free; 2588 } 2589 2590 skb->protocol = htons(ETH_P_IP); 2591 skb->dev = dev; 2592 skb->mark = mark; 2593 local_bh_disable(); 2594 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 2595 local_bh_enable(); 2596 2597 rt = skb_rtable(skb); 2598 if (err == 0 && rt->dst.error) 2599 err = -rt->dst.error; 2600 } else { 2601 rt = ip_route_output_key(net, &fl4); 2602 2603 err = 0; 2604 if (IS_ERR(rt)) 2605 err = PTR_ERR(rt); 2606 } 2607 2608 if (err) 2609 goto errout_free; 2610 2611 skb_dst_set(skb, &rt->dst); 2612 if (rtm->rtm_flags & RTM_F_NOTIFY) 2613 rt->rt_flags |= RTCF_NOTIFY; 2614 2615 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2616 table_id = rt->rt_table_id; 2617 2618 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2619 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2620 RTM_NEWROUTE, 0, 0); 2621 if (err < 0) 2622 goto errout_free; 2623 2624 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2625 errout: 2626 return err; 2627 2628 errout_free: 2629 kfree_skb(skb); 2630 goto errout; 2631 } 2632 2633 void ip_rt_multicast_event(struct in_device *in_dev) 2634 { 2635 rt_cache_flush(dev_net(in_dev->dev)); 2636 } 2637 2638 #ifdef CONFIG_SYSCTL 2639 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2640 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2641 static int ip_rt_gc_elasticity __read_mostly = 8; 2642 2643 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2644 void __user *buffer, 2645 size_t *lenp, loff_t *ppos) 2646 { 2647 struct net *net = (struct net *)__ctl->extra1; 2648 2649 if (write) { 2650 rt_cache_flush(net); 2651 fnhe_genid_bump(net); 2652 return 0; 2653 } 2654 2655 return -EINVAL; 2656 } 2657 2658 static struct ctl_table ipv4_route_table[] = { 2659 { 2660 .procname = "gc_thresh", 2661 .data = &ipv4_dst_ops.gc_thresh, 2662 .maxlen = sizeof(int), 2663 .mode = 0644, 2664 .proc_handler = proc_dointvec, 2665 }, 2666 { 2667 .procname = "max_size", 2668 .data = &ip_rt_max_size, 2669 .maxlen = sizeof(int), 2670 .mode = 0644, 2671 .proc_handler = proc_dointvec, 2672 }, 2673 { 2674 /* Deprecated. Use gc_min_interval_ms */ 2675 2676 .procname = "gc_min_interval", 2677 .data = &ip_rt_gc_min_interval, 2678 .maxlen = sizeof(int), 2679 .mode = 0644, 2680 .proc_handler = proc_dointvec_jiffies, 2681 }, 2682 { 2683 .procname = "gc_min_interval_ms", 2684 .data = &ip_rt_gc_min_interval, 2685 .maxlen = sizeof(int), 2686 .mode = 0644, 2687 .proc_handler = proc_dointvec_ms_jiffies, 2688 }, 2689 { 2690 .procname = "gc_timeout", 2691 .data = &ip_rt_gc_timeout, 2692 .maxlen = sizeof(int), 2693 .mode = 0644, 2694 .proc_handler = proc_dointvec_jiffies, 2695 }, 2696 { 2697 .procname = "gc_interval", 2698 .data = &ip_rt_gc_interval, 2699 .maxlen = sizeof(int), 2700 .mode = 0644, 2701 .proc_handler = proc_dointvec_jiffies, 2702 }, 2703 { 2704 .procname = "redirect_load", 2705 .data = &ip_rt_redirect_load, 2706 .maxlen = sizeof(int), 2707 .mode = 0644, 2708 .proc_handler = proc_dointvec, 2709 }, 2710 { 2711 .procname = "redirect_number", 2712 .data = &ip_rt_redirect_number, 2713 .maxlen = sizeof(int), 2714 .mode = 0644, 2715 .proc_handler = proc_dointvec, 2716 }, 2717 { 2718 .procname = "redirect_silence", 2719 .data = &ip_rt_redirect_silence, 2720 .maxlen = sizeof(int), 2721 .mode = 0644, 2722 .proc_handler = proc_dointvec, 2723 }, 2724 { 2725 .procname = "error_cost", 2726 .data = &ip_rt_error_cost, 2727 .maxlen = sizeof(int), 2728 .mode = 0644, 2729 .proc_handler = proc_dointvec, 2730 }, 2731 { 2732 .procname = "error_burst", 2733 .data = &ip_rt_error_burst, 2734 .maxlen = sizeof(int), 2735 .mode = 0644, 2736 .proc_handler = proc_dointvec, 2737 }, 2738 { 2739 .procname = "gc_elasticity", 2740 .data = &ip_rt_gc_elasticity, 2741 .maxlen = sizeof(int), 2742 .mode = 0644, 2743 .proc_handler = proc_dointvec, 2744 }, 2745 { 2746 .procname = "mtu_expires", 2747 .data = &ip_rt_mtu_expires, 2748 .maxlen = sizeof(int), 2749 .mode = 0644, 2750 .proc_handler = proc_dointvec_jiffies, 2751 }, 2752 { 2753 .procname = "min_pmtu", 2754 .data = &ip_rt_min_pmtu, 2755 .maxlen = sizeof(int), 2756 .mode = 0644, 2757 .proc_handler = proc_dointvec, 2758 }, 2759 { 2760 .procname = "min_adv_mss", 2761 .data = &ip_rt_min_advmss, 2762 .maxlen = sizeof(int), 2763 .mode = 0644, 2764 .proc_handler = proc_dointvec, 2765 }, 2766 { } 2767 }; 2768 2769 static struct ctl_table ipv4_route_flush_table[] = { 2770 { 2771 .procname = "flush", 2772 .maxlen = sizeof(int), 2773 .mode = 0200, 2774 .proc_handler = ipv4_sysctl_rtcache_flush, 2775 }, 2776 { }, 2777 }; 2778 2779 static __net_init int sysctl_route_net_init(struct net *net) 2780 { 2781 struct ctl_table *tbl; 2782 2783 tbl = ipv4_route_flush_table; 2784 if (!net_eq(net, &init_net)) { 2785 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2786 if (!tbl) 2787 goto err_dup; 2788 2789 /* Don't export sysctls to unprivileged users */ 2790 if (net->user_ns != &init_user_ns) 2791 tbl[0].procname = NULL; 2792 } 2793 tbl[0].extra1 = net; 2794 2795 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2796 if (!net->ipv4.route_hdr) 2797 goto err_reg; 2798 return 0; 2799 2800 err_reg: 2801 if (tbl != ipv4_route_flush_table) 2802 kfree(tbl); 2803 err_dup: 2804 return -ENOMEM; 2805 } 2806 2807 static __net_exit void sysctl_route_net_exit(struct net *net) 2808 { 2809 struct ctl_table *tbl; 2810 2811 tbl = net->ipv4.route_hdr->ctl_table_arg; 2812 unregister_net_sysctl_table(net->ipv4.route_hdr); 2813 BUG_ON(tbl == ipv4_route_flush_table); 2814 kfree(tbl); 2815 } 2816 2817 static __net_initdata struct pernet_operations sysctl_route_ops = { 2818 .init = sysctl_route_net_init, 2819 .exit = sysctl_route_net_exit, 2820 }; 2821 #endif 2822 2823 static __net_init int rt_genid_init(struct net *net) 2824 { 2825 atomic_set(&net->ipv4.rt_genid, 0); 2826 atomic_set(&net->fnhe_genid, 0); 2827 get_random_bytes(&net->ipv4.dev_addr_genid, 2828 sizeof(net->ipv4.dev_addr_genid)); 2829 return 0; 2830 } 2831 2832 static __net_initdata struct pernet_operations rt_genid_ops = { 2833 .init = rt_genid_init, 2834 }; 2835 2836 static int __net_init ipv4_inetpeer_init(struct net *net) 2837 { 2838 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 2839 2840 if (!bp) 2841 return -ENOMEM; 2842 inet_peer_base_init(bp); 2843 net->ipv4.peers = bp; 2844 return 0; 2845 } 2846 2847 static void __net_exit ipv4_inetpeer_exit(struct net *net) 2848 { 2849 struct inet_peer_base *bp = net->ipv4.peers; 2850 2851 net->ipv4.peers = NULL; 2852 inetpeer_invalidate_tree(bp); 2853 kfree(bp); 2854 } 2855 2856 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 2857 .init = ipv4_inetpeer_init, 2858 .exit = ipv4_inetpeer_exit, 2859 }; 2860 2861 #ifdef CONFIG_IP_ROUTE_CLASSID 2862 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 2863 #endif /* CONFIG_IP_ROUTE_CLASSID */ 2864 2865 int __init ip_rt_init(void) 2866 { 2867 int rc = 0; 2868 int cpu; 2869 2870 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 2871 if (!ip_idents) 2872 panic("IP: failed to allocate ip_idents\n"); 2873 2874 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 2875 2876 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 2877 if (!ip_tstamps) 2878 panic("IP: failed to allocate ip_tstamps\n"); 2879 2880 for_each_possible_cpu(cpu) { 2881 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 2882 2883 INIT_LIST_HEAD(&ul->head); 2884 spin_lock_init(&ul->lock); 2885 } 2886 #ifdef CONFIG_IP_ROUTE_CLASSID 2887 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 2888 if (!ip_rt_acct) 2889 panic("IP: failed to allocate ip_rt_acct\n"); 2890 #endif 2891 2892 ipv4_dst_ops.kmem_cachep = 2893 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 2894 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2895 2896 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 2897 2898 if (dst_entries_init(&ipv4_dst_ops) < 0) 2899 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 2900 2901 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 2902 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 2903 2904 ipv4_dst_ops.gc_thresh = ~0; 2905 ip_rt_max_size = INT_MAX; 2906 2907 devinet_init(); 2908 ip_fib_init(); 2909 2910 if (ip_rt_proc_init()) 2911 pr_err("Unable to create route proc files\n"); 2912 #ifdef CONFIG_XFRM 2913 xfrm_init(); 2914 xfrm4_init(); 2915 #endif 2916 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); 2917 2918 #ifdef CONFIG_SYSCTL 2919 register_pernet_subsys(&sysctl_route_ops); 2920 #endif 2921 register_pernet_subsys(&rt_genid_ops); 2922 register_pernet_subsys(&ipv4_inetpeer_ops); 2923 return rc; 2924 } 2925 2926 #ifdef CONFIG_SYSCTL 2927 /* 2928 * We really need to sanitize the damn ipv4 init order, then all 2929 * this nonsense will go away. 2930 */ 2931 void __init ip_static_sysctl_init(void) 2932 { 2933 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 2934 } 2935 #endif 2936