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 <linux/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 #include "fib_lookup.h" 118 119 #define RT_FL_TOS(oldflp4) \ 120 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 121 122 #define RT_GC_TIMEOUT (300*HZ) 123 124 static int ip_rt_max_size; 125 static int ip_rt_redirect_number __read_mostly = 9; 126 static int ip_rt_redirect_load __read_mostly = HZ / 50; 127 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 128 static int ip_rt_error_cost __read_mostly = HZ; 129 static int ip_rt_error_burst __read_mostly = 5 * HZ; 130 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 131 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 132 static int ip_rt_min_advmss __read_mostly = 256; 133 134 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 135 /* 136 * Interface to generic destination cache. 137 */ 138 139 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 140 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 141 static unsigned int ipv4_mtu(const struct dst_entry *dst); 142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 143 static void ipv4_link_failure(struct sk_buff *skb); 144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 145 struct sk_buff *skb, u32 mtu); 146 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 147 struct sk_buff *skb); 148 static void ipv4_dst_destroy(struct dst_entry *dst); 149 150 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 151 { 152 WARN_ON(1); 153 return NULL; 154 } 155 156 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 157 struct sk_buff *skb, 158 const void *daddr); 159 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 160 161 static struct dst_ops ipv4_dst_ops = { 162 .family = AF_INET, 163 .check = ipv4_dst_check, 164 .default_advmss = ipv4_default_advmss, 165 .mtu = ipv4_mtu, 166 .cow_metrics = ipv4_cow_metrics, 167 .destroy = ipv4_dst_destroy, 168 .negative_advice = ipv4_negative_advice, 169 .link_failure = ipv4_link_failure, 170 .update_pmtu = ip_rt_update_pmtu, 171 .redirect = ip_do_redirect, 172 .local_out = __ip_local_out, 173 .neigh_lookup = ipv4_neigh_lookup, 174 .confirm_neigh = ipv4_confirm_neigh, 175 }; 176 177 #define ECN_OR_COST(class) TC_PRIO_##class 178 179 const __u8 ip_tos2prio[16] = { 180 TC_PRIO_BESTEFFORT, 181 ECN_OR_COST(BESTEFFORT), 182 TC_PRIO_BESTEFFORT, 183 ECN_OR_COST(BESTEFFORT), 184 TC_PRIO_BULK, 185 ECN_OR_COST(BULK), 186 TC_PRIO_BULK, 187 ECN_OR_COST(BULK), 188 TC_PRIO_INTERACTIVE, 189 ECN_OR_COST(INTERACTIVE), 190 TC_PRIO_INTERACTIVE, 191 ECN_OR_COST(INTERACTIVE), 192 TC_PRIO_INTERACTIVE_BULK, 193 ECN_OR_COST(INTERACTIVE_BULK), 194 TC_PRIO_INTERACTIVE_BULK, 195 ECN_OR_COST(INTERACTIVE_BULK) 196 }; 197 EXPORT_SYMBOL(ip_tos2prio); 198 199 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 200 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 201 202 #ifdef CONFIG_PROC_FS 203 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 204 { 205 if (*pos) 206 return NULL; 207 return SEQ_START_TOKEN; 208 } 209 210 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 211 { 212 ++*pos; 213 return NULL; 214 } 215 216 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 217 { 218 } 219 220 static int rt_cache_seq_show(struct seq_file *seq, void *v) 221 { 222 if (v == SEQ_START_TOKEN) 223 seq_printf(seq, "%-127s\n", 224 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 225 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 226 "HHUptod\tSpecDst"); 227 return 0; 228 } 229 230 static const struct seq_operations rt_cache_seq_ops = { 231 .start = rt_cache_seq_start, 232 .next = rt_cache_seq_next, 233 .stop = rt_cache_seq_stop, 234 .show = rt_cache_seq_show, 235 }; 236 237 static int rt_cache_seq_open(struct inode *inode, struct file *file) 238 { 239 return seq_open(file, &rt_cache_seq_ops); 240 } 241 242 static const struct file_operations rt_cache_seq_fops = { 243 .open = rt_cache_seq_open, 244 .read = seq_read, 245 .llseek = seq_lseek, 246 .release = seq_release, 247 }; 248 249 250 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 251 { 252 int cpu; 253 254 if (*pos == 0) 255 return SEQ_START_TOKEN; 256 257 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 258 if (!cpu_possible(cpu)) 259 continue; 260 *pos = cpu+1; 261 return &per_cpu(rt_cache_stat, cpu); 262 } 263 return NULL; 264 } 265 266 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 267 { 268 int cpu; 269 270 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 271 if (!cpu_possible(cpu)) 272 continue; 273 *pos = cpu+1; 274 return &per_cpu(rt_cache_stat, cpu); 275 } 276 return NULL; 277 278 } 279 280 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 281 { 282 283 } 284 285 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 286 { 287 struct rt_cache_stat *st = v; 288 289 if (v == SEQ_START_TOKEN) { 290 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"); 291 return 0; 292 } 293 294 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 295 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 296 dst_entries_get_slow(&ipv4_dst_ops), 297 0, /* st->in_hit */ 298 st->in_slow_tot, 299 st->in_slow_mc, 300 st->in_no_route, 301 st->in_brd, 302 st->in_martian_dst, 303 st->in_martian_src, 304 305 0, /* st->out_hit */ 306 st->out_slow_tot, 307 st->out_slow_mc, 308 309 0, /* st->gc_total */ 310 0, /* st->gc_ignored */ 311 0, /* st->gc_goal_miss */ 312 0, /* st->gc_dst_overflow */ 313 0, /* st->in_hlist_search */ 314 0 /* st->out_hlist_search */ 315 ); 316 return 0; 317 } 318 319 static const struct seq_operations rt_cpu_seq_ops = { 320 .start = rt_cpu_seq_start, 321 .next = rt_cpu_seq_next, 322 .stop = rt_cpu_seq_stop, 323 .show = rt_cpu_seq_show, 324 }; 325 326 327 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 328 { 329 return seq_open(file, &rt_cpu_seq_ops); 330 } 331 332 static const struct file_operations rt_cpu_seq_fops = { 333 .open = rt_cpu_seq_open, 334 .read = seq_read, 335 .llseek = seq_lseek, 336 .release = seq_release, 337 }; 338 339 #ifdef CONFIG_IP_ROUTE_CLASSID 340 static int rt_acct_proc_show(struct seq_file *m, void *v) 341 { 342 struct ip_rt_acct *dst, *src; 343 unsigned int i, j; 344 345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 346 if (!dst) 347 return -ENOMEM; 348 349 for_each_possible_cpu(i) { 350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 351 for (j = 0; j < 256; j++) { 352 dst[j].o_bytes += src[j].o_bytes; 353 dst[j].o_packets += src[j].o_packets; 354 dst[j].i_bytes += src[j].i_bytes; 355 dst[j].i_packets += src[j].i_packets; 356 } 357 } 358 359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 360 kfree(dst); 361 return 0; 362 } 363 364 static int rt_acct_proc_open(struct inode *inode, struct file *file) 365 { 366 return single_open(file, rt_acct_proc_show, NULL); 367 } 368 369 static const struct file_operations rt_acct_proc_fops = { 370 .open = rt_acct_proc_open, 371 .read = seq_read, 372 .llseek = seq_lseek, 373 .release = single_release, 374 }; 375 #endif 376 377 static int __net_init ip_rt_do_proc_init(struct net *net) 378 { 379 struct proc_dir_entry *pde; 380 381 pde = proc_create("rt_cache", S_IRUGO, net->proc_net, 382 &rt_cache_seq_fops); 383 if (!pde) 384 goto err1; 385 386 pde = proc_create("rt_cache", S_IRUGO, 387 net->proc_net_stat, &rt_cpu_seq_fops); 388 if (!pde) 389 goto err2; 390 391 #ifdef CONFIG_IP_ROUTE_CLASSID 392 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops); 393 if (!pde) 394 goto err3; 395 #endif 396 return 0; 397 398 #ifdef CONFIG_IP_ROUTE_CLASSID 399 err3: 400 remove_proc_entry("rt_cache", net->proc_net_stat); 401 #endif 402 err2: 403 remove_proc_entry("rt_cache", net->proc_net); 404 err1: 405 return -ENOMEM; 406 } 407 408 static void __net_exit ip_rt_do_proc_exit(struct net *net) 409 { 410 remove_proc_entry("rt_cache", net->proc_net_stat); 411 remove_proc_entry("rt_cache", net->proc_net); 412 #ifdef CONFIG_IP_ROUTE_CLASSID 413 remove_proc_entry("rt_acct", net->proc_net); 414 #endif 415 } 416 417 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 418 .init = ip_rt_do_proc_init, 419 .exit = ip_rt_do_proc_exit, 420 }; 421 422 static int __init ip_rt_proc_init(void) 423 { 424 return register_pernet_subsys(&ip_rt_proc_ops); 425 } 426 427 #else 428 static inline int ip_rt_proc_init(void) 429 { 430 return 0; 431 } 432 #endif /* CONFIG_PROC_FS */ 433 434 static inline bool rt_is_expired(const struct rtable *rth) 435 { 436 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 437 } 438 439 void rt_cache_flush(struct net *net) 440 { 441 rt_genid_bump_ipv4(net); 442 } 443 444 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 445 struct sk_buff *skb, 446 const void *daddr) 447 { 448 struct net_device *dev = dst->dev; 449 const __be32 *pkey = daddr; 450 const struct rtable *rt; 451 struct neighbour *n; 452 453 rt = (const struct rtable *) dst; 454 if (rt->rt_gateway) 455 pkey = (const __be32 *) &rt->rt_gateway; 456 else if (skb) 457 pkey = &ip_hdr(skb)->daddr; 458 459 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); 460 if (n) 461 return n; 462 return neigh_create(&arp_tbl, pkey, dev); 463 } 464 465 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 466 { 467 struct net_device *dev = dst->dev; 468 const __be32 *pkey = daddr; 469 const struct rtable *rt; 470 471 rt = (const struct rtable *)dst; 472 if (rt->rt_gateway) 473 pkey = (const __be32 *)&rt->rt_gateway; 474 else if (!daddr || 475 (rt->rt_flags & 476 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) 477 return; 478 479 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 480 } 481 482 #define IP_IDENTS_SZ 2048u 483 484 static atomic_t *ip_idents __read_mostly; 485 static u32 *ip_tstamps __read_mostly; 486 487 /* In order to protect privacy, we add a perturbation to identifiers 488 * if one generator is seldom used. This makes hard for an attacker 489 * to infer how many packets were sent between two points in time. 490 */ 491 u32 ip_idents_reserve(u32 hash, int segs) 492 { 493 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 494 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 495 u32 old = READ_ONCE(*p_tstamp); 496 u32 now = (u32)jiffies; 497 u32 new, delta = 0; 498 499 if (old != now && cmpxchg(p_tstamp, old, now) == old) 500 delta = prandom_u32_max(now - old); 501 502 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 503 do { 504 old = (u32)atomic_read(p_id); 505 new = old + delta + segs; 506 } while (atomic_cmpxchg(p_id, old, new) != old); 507 508 return new - segs; 509 } 510 EXPORT_SYMBOL(ip_idents_reserve); 511 512 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 513 { 514 static u32 ip_idents_hashrnd __read_mostly; 515 u32 hash, id; 516 517 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); 518 519 hash = jhash_3words((__force u32)iph->daddr, 520 (__force u32)iph->saddr, 521 iph->protocol ^ net_hash_mix(net), 522 ip_idents_hashrnd); 523 id = ip_idents_reserve(hash, segs); 524 iph->id = htons(id); 525 } 526 EXPORT_SYMBOL(__ip_select_ident); 527 528 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 529 const struct sock *sk, 530 const struct iphdr *iph, 531 int oif, u8 tos, 532 u8 prot, u32 mark, int flow_flags) 533 { 534 if (sk) { 535 const struct inet_sock *inet = inet_sk(sk); 536 537 oif = sk->sk_bound_dev_if; 538 mark = sk->sk_mark; 539 tos = RT_CONN_FLAGS(sk); 540 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 541 } 542 flowi4_init_output(fl4, oif, mark, tos, 543 RT_SCOPE_UNIVERSE, prot, 544 flow_flags, 545 iph->daddr, iph->saddr, 0, 0, 546 sock_net_uid(net, sk)); 547 } 548 549 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 550 const struct sock *sk) 551 { 552 const struct net *net = dev_net(skb->dev); 553 const struct iphdr *iph = ip_hdr(skb); 554 int oif = skb->dev->ifindex; 555 u8 tos = RT_TOS(iph->tos); 556 u8 prot = iph->protocol; 557 u32 mark = skb->mark; 558 559 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 560 } 561 562 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 563 { 564 const struct inet_sock *inet = inet_sk(sk); 565 const struct ip_options_rcu *inet_opt; 566 __be32 daddr = inet->inet_daddr; 567 568 rcu_read_lock(); 569 inet_opt = rcu_dereference(inet->inet_opt); 570 if (inet_opt && inet_opt->opt.srr) 571 daddr = inet_opt->opt.faddr; 572 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 573 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 574 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 575 inet_sk_flowi_flags(sk), 576 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 577 rcu_read_unlock(); 578 } 579 580 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 581 const struct sk_buff *skb) 582 { 583 if (skb) 584 build_skb_flow_key(fl4, skb, sk); 585 else 586 build_sk_flow_key(fl4, sk); 587 } 588 589 static DEFINE_SPINLOCK(fnhe_lock); 590 591 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 592 { 593 struct rtable *rt; 594 595 rt = rcu_dereference(fnhe->fnhe_rth_input); 596 if (rt) { 597 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 598 dst_dev_put(&rt->dst); 599 dst_release(&rt->dst); 600 } 601 rt = rcu_dereference(fnhe->fnhe_rth_output); 602 if (rt) { 603 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 604 dst_dev_put(&rt->dst); 605 dst_release(&rt->dst); 606 } 607 } 608 609 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 610 { 611 struct fib_nh_exception *fnhe, *oldest; 612 613 oldest = rcu_dereference(hash->chain); 614 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 615 fnhe = rcu_dereference(fnhe->fnhe_next)) { 616 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 617 oldest = fnhe; 618 } 619 fnhe_flush_routes(oldest); 620 return oldest; 621 } 622 623 static inline u32 fnhe_hashfun(__be32 daddr) 624 { 625 static u32 fnhe_hashrnd __read_mostly; 626 u32 hval; 627 628 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 629 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 630 return hash_32(hval, FNHE_HASH_SHIFT); 631 } 632 633 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 634 { 635 rt->rt_pmtu = fnhe->fnhe_pmtu; 636 rt->dst.expires = fnhe->fnhe_expires; 637 638 if (fnhe->fnhe_gw) { 639 rt->rt_flags |= RTCF_REDIRECTED; 640 rt->rt_gateway = fnhe->fnhe_gw; 641 rt->rt_uses_gateway = 1; 642 } 643 } 644 645 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 646 u32 pmtu, unsigned long expires) 647 { 648 struct fnhe_hash_bucket *hash; 649 struct fib_nh_exception *fnhe; 650 struct rtable *rt; 651 u32 genid, hval; 652 unsigned int i; 653 int depth; 654 655 genid = fnhe_genid(dev_net(nh->nh_dev)); 656 hval = fnhe_hashfun(daddr); 657 658 spin_lock_bh(&fnhe_lock); 659 660 hash = rcu_dereference(nh->nh_exceptions); 661 if (!hash) { 662 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 663 if (!hash) 664 goto out_unlock; 665 rcu_assign_pointer(nh->nh_exceptions, hash); 666 } 667 668 hash += hval; 669 670 depth = 0; 671 for (fnhe = rcu_dereference(hash->chain); fnhe; 672 fnhe = rcu_dereference(fnhe->fnhe_next)) { 673 if (fnhe->fnhe_daddr == daddr) 674 break; 675 depth++; 676 } 677 678 if (fnhe) { 679 if (fnhe->fnhe_genid != genid) 680 fnhe->fnhe_genid = genid; 681 if (gw) 682 fnhe->fnhe_gw = gw; 683 if (pmtu) 684 fnhe->fnhe_pmtu = pmtu; 685 fnhe->fnhe_expires = max(1UL, expires); 686 /* Update all cached dsts too */ 687 rt = rcu_dereference(fnhe->fnhe_rth_input); 688 if (rt) 689 fill_route_from_fnhe(rt, fnhe); 690 rt = rcu_dereference(fnhe->fnhe_rth_output); 691 if (rt) 692 fill_route_from_fnhe(rt, fnhe); 693 } else { 694 if (depth > FNHE_RECLAIM_DEPTH) 695 fnhe = fnhe_oldest(hash); 696 else { 697 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 698 if (!fnhe) 699 goto out_unlock; 700 701 fnhe->fnhe_next = hash->chain; 702 rcu_assign_pointer(hash->chain, fnhe); 703 } 704 fnhe->fnhe_genid = genid; 705 fnhe->fnhe_daddr = daddr; 706 fnhe->fnhe_gw = gw; 707 fnhe->fnhe_pmtu = pmtu; 708 fnhe->fnhe_expires = expires; 709 710 /* Exception created; mark the cached routes for the nexthop 711 * stale, so anyone caching it rechecks if this exception 712 * applies to them. 713 */ 714 rt = rcu_dereference(nh->nh_rth_input); 715 if (rt) 716 rt->dst.obsolete = DST_OBSOLETE_KILL; 717 718 for_each_possible_cpu(i) { 719 struct rtable __rcu **prt; 720 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 721 rt = rcu_dereference(*prt); 722 if (rt) 723 rt->dst.obsolete = DST_OBSOLETE_KILL; 724 } 725 } 726 727 fnhe->fnhe_stamp = jiffies; 728 729 out_unlock: 730 spin_unlock_bh(&fnhe_lock); 731 } 732 733 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 734 bool kill_route) 735 { 736 __be32 new_gw = icmp_hdr(skb)->un.gateway; 737 __be32 old_gw = ip_hdr(skb)->saddr; 738 struct net_device *dev = skb->dev; 739 struct in_device *in_dev; 740 struct fib_result res; 741 struct neighbour *n; 742 struct net *net; 743 744 switch (icmp_hdr(skb)->code & 7) { 745 case ICMP_REDIR_NET: 746 case ICMP_REDIR_NETTOS: 747 case ICMP_REDIR_HOST: 748 case ICMP_REDIR_HOSTTOS: 749 break; 750 751 default: 752 return; 753 } 754 755 if (rt->rt_gateway != old_gw) 756 return; 757 758 in_dev = __in_dev_get_rcu(dev); 759 if (!in_dev) 760 return; 761 762 net = dev_net(dev); 763 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 764 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 765 ipv4_is_zeronet(new_gw)) 766 goto reject_redirect; 767 768 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 769 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 770 goto reject_redirect; 771 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 772 goto reject_redirect; 773 } else { 774 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 775 goto reject_redirect; 776 } 777 778 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 779 if (!n) 780 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 781 if (!IS_ERR(n)) { 782 if (!(n->nud_state & NUD_VALID)) { 783 neigh_event_send(n, NULL); 784 } else { 785 if (fib_lookup(net, fl4, &res, 0) == 0) { 786 struct fib_nh *nh = &FIB_RES_NH(res); 787 788 update_or_create_fnhe(nh, fl4->daddr, new_gw, 789 0, jiffies + ip_rt_gc_timeout); 790 } 791 if (kill_route) 792 rt->dst.obsolete = DST_OBSOLETE_KILL; 793 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 794 } 795 neigh_release(n); 796 } 797 return; 798 799 reject_redirect: 800 #ifdef CONFIG_IP_ROUTE_VERBOSE 801 if (IN_DEV_LOG_MARTIANS(in_dev)) { 802 const struct iphdr *iph = (const struct iphdr *) skb->data; 803 __be32 daddr = iph->daddr; 804 __be32 saddr = iph->saddr; 805 806 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 807 " Advised path = %pI4 -> %pI4\n", 808 &old_gw, dev->name, &new_gw, 809 &saddr, &daddr); 810 } 811 #endif 812 ; 813 } 814 815 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 816 { 817 struct rtable *rt; 818 struct flowi4 fl4; 819 const struct iphdr *iph = (const struct iphdr *) skb->data; 820 struct net *net = dev_net(skb->dev); 821 int oif = skb->dev->ifindex; 822 u8 tos = RT_TOS(iph->tos); 823 u8 prot = iph->protocol; 824 u32 mark = skb->mark; 825 826 rt = (struct rtable *) dst; 827 828 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 829 __ip_do_redirect(rt, skb, &fl4, true); 830 } 831 832 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 833 { 834 struct rtable *rt = (struct rtable *)dst; 835 struct dst_entry *ret = dst; 836 837 if (rt) { 838 if (dst->obsolete > 0) { 839 ip_rt_put(rt); 840 ret = NULL; 841 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 842 rt->dst.expires) { 843 ip_rt_put(rt); 844 ret = NULL; 845 } 846 } 847 return ret; 848 } 849 850 /* 851 * Algorithm: 852 * 1. The first ip_rt_redirect_number redirects are sent 853 * with exponential backoff, then we stop sending them at all, 854 * assuming that the host ignores our redirects. 855 * 2. If we did not see packets requiring redirects 856 * during ip_rt_redirect_silence, we assume that the host 857 * forgot redirected route and start to send redirects again. 858 * 859 * This algorithm is much cheaper and more intelligent than dumb load limiting 860 * in icmp.c. 861 * 862 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 863 * and "frag. need" (breaks PMTU discovery) in icmp.c. 864 */ 865 866 void ip_rt_send_redirect(struct sk_buff *skb) 867 { 868 struct rtable *rt = skb_rtable(skb); 869 struct in_device *in_dev; 870 struct inet_peer *peer; 871 struct net *net; 872 int log_martians; 873 int vif; 874 875 rcu_read_lock(); 876 in_dev = __in_dev_get_rcu(rt->dst.dev); 877 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 878 rcu_read_unlock(); 879 return; 880 } 881 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 882 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 883 rcu_read_unlock(); 884 885 net = dev_net(rt->dst.dev); 886 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 887 if (!peer) { 888 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 889 rt_nexthop(rt, ip_hdr(skb)->daddr)); 890 return; 891 } 892 893 /* No redirected packets during ip_rt_redirect_silence; 894 * reset the algorithm. 895 */ 896 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 897 peer->rate_tokens = 0; 898 899 /* Too many ignored redirects; do not send anything 900 * set dst.rate_last to the last seen redirected packet. 901 */ 902 if (peer->rate_tokens >= ip_rt_redirect_number) { 903 peer->rate_last = jiffies; 904 goto out_put_peer; 905 } 906 907 /* Check for load limit; set rate_last to the latest sent 908 * redirect. 909 */ 910 if (peer->rate_tokens == 0 || 911 time_after(jiffies, 912 (peer->rate_last + 913 (ip_rt_redirect_load << peer->rate_tokens)))) { 914 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 915 916 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 917 peer->rate_last = jiffies; 918 ++peer->rate_tokens; 919 #ifdef CONFIG_IP_ROUTE_VERBOSE 920 if (log_martians && 921 peer->rate_tokens == ip_rt_redirect_number) 922 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 923 &ip_hdr(skb)->saddr, inet_iif(skb), 924 &ip_hdr(skb)->daddr, &gw); 925 #endif 926 } 927 out_put_peer: 928 inet_putpeer(peer); 929 } 930 931 static int ip_error(struct sk_buff *skb) 932 { 933 struct in_device *in_dev = __in_dev_get_rcu(skb->dev); 934 struct rtable *rt = skb_rtable(skb); 935 struct inet_peer *peer; 936 unsigned long now; 937 struct net *net; 938 bool send; 939 int code; 940 941 /* IP on this device is disabled. */ 942 if (!in_dev) 943 goto out; 944 945 net = dev_net(rt->dst.dev); 946 if (!IN_DEV_FORWARD(in_dev)) { 947 switch (rt->dst.error) { 948 case EHOSTUNREACH: 949 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 950 break; 951 952 case ENETUNREACH: 953 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 954 break; 955 } 956 goto out; 957 } 958 959 switch (rt->dst.error) { 960 case EINVAL: 961 default: 962 goto out; 963 case EHOSTUNREACH: 964 code = ICMP_HOST_UNREACH; 965 break; 966 case ENETUNREACH: 967 code = ICMP_NET_UNREACH; 968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 969 break; 970 case EACCES: 971 code = ICMP_PKT_FILTERED; 972 break; 973 } 974 975 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 976 l3mdev_master_ifindex(skb->dev), 1); 977 978 send = true; 979 if (peer) { 980 now = jiffies; 981 peer->rate_tokens += now - peer->rate_last; 982 if (peer->rate_tokens > ip_rt_error_burst) 983 peer->rate_tokens = ip_rt_error_burst; 984 peer->rate_last = now; 985 if (peer->rate_tokens >= ip_rt_error_cost) 986 peer->rate_tokens -= ip_rt_error_cost; 987 else 988 send = false; 989 inet_putpeer(peer); 990 } 991 if (send) 992 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 993 994 out: kfree_skb(skb); 995 return 0; 996 } 997 998 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 999 { 1000 struct dst_entry *dst = &rt->dst; 1001 struct fib_result res; 1002 1003 if (dst_metric_locked(dst, RTAX_MTU)) 1004 return; 1005 1006 if (ipv4_mtu(dst) < mtu) 1007 return; 1008 1009 if (mtu < ip_rt_min_pmtu) 1010 mtu = ip_rt_min_pmtu; 1011 1012 if (rt->rt_pmtu == mtu && 1013 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1014 return; 1015 1016 rcu_read_lock(); 1017 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1018 struct fib_nh *nh = &FIB_RES_NH(res); 1019 1020 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, 1021 jiffies + ip_rt_mtu_expires); 1022 } 1023 rcu_read_unlock(); 1024 } 1025 1026 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1027 struct sk_buff *skb, u32 mtu) 1028 { 1029 struct rtable *rt = (struct rtable *) dst; 1030 struct flowi4 fl4; 1031 1032 ip_rt_build_flow_key(&fl4, sk, skb); 1033 __ip_rt_update_pmtu(rt, &fl4, mtu); 1034 } 1035 1036 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1037 int oif, u32 mark, u8 protocol, int flow_flags) 1038 { 1039 const struct iphdr *iph = (const struct iphdr *) skb->data; 1040 struct flowi4 fl4; 1041 struct rtable *rt; 1042 1043 if (!mark) 1044 mark = IP4_REPLY_MARK(net, skb->mark); 1045 1046 __build_flow_key(net, &fl4, NULL, iph, oif, 1047 RT_TOS(iph->tos), protocol, mark, flow_flags); 1048 rt = __ip_route_output_key(net, &fl4); 1049 if (!IS_ERR(rt)) { 1050 __ip_rt_update_pmtu(rt, &fl4, mtu); 1051 ip_rt_put(rt); 1052 } 1053 } 1054 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1055 1056 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1057 { 1058 const struct iphdr *iph = (const struct iphdr *) skb->data; 1059 struct flowi4 fl4; 1060 struct rtable *rt; 1061 1062 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1063 1064 if (!fl4.flowi4_mark) 1065 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1066 1067 rt = __ip_route_output_key(sock_net(sk), &fl4); 1068 if (!IS_ERR(rt)) { 1069 __ip_rt_update_pmtu(rt, &fl4, mtu); 1070 ip_rt_put(rt); 1071 } 1072 } 1073 1074 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1075 { 1076 const struct iphdr *iph = (const struct iphdr *) skb->data; 1077 struct flowi4 fl4; 1078 struct rtable *rt; 1079 struct dst_entry *odst = NULL; 1080 bool new = false; 1081 struct net *net = sock_net(sk); 1082 1083 bh_lock_sock(sk); 1084 1085 if (!ip_sk_accept_pmtu(sk)) 1086 goto out; 1087 1088 odst = sk_dst_get(sk); 1089 1090 if (sock_owned_by_user(sk) || !odst) { 1091 __ipv4_sk_update_pmtu(skb, sk, mtu); 1092 goto out; 1093 } 1094 1095 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1096 1097 rt = (struct rtable *)odst; 1098 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1099 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1100 if (IS_ERR(rt)) 1101 goto out; 1102 1103 new = true; 1104 } 1105 1106 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1107 1108 if (!dst_check(&rt->dst, 0)) { 1109 if (new) 1110 dst_release(&rt->dst); 1111 1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1113 if (IS_ERR(rt)) 1114 goto out; 1115 1116 new = true; 1117 } 1118 1119 if (new) 1120 sk_dst_set(sk, &rt->dst); 1121 1122 out: 1123 bh_unlock_sock(sk); 1124 dst_release(odst); 1125 } 1126 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1127 1128 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1129 int oif, u32 mark, u8 protocol, int flow_flags) 1130 { 1131 const struct iphdr *iph = (const struct iphdr *) skb->data; 1132 struct flowi4 fl4; 1133 struct rtable *rt; 1134 1135 __build_flow_key(net, &fl4, NULL, iph, oif, 1136 RT_TOS(iph->tos), protocol, mark, flow_flags); 1137 rt = __ip_route_output_key(net, &fl4); 1138 if (!IS_ERR(rt)) { 1139 __ip_do_redirect(rt, skb, &fl4, false); 1140 ip_rt_put(rt); 1141 } 1142 } 1143 EXPORT_SYMBOL_GPL(ipv4_redirect); 1144 1145 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1146 { 1147 const struct iphdr *iph = (const struct iphdr *) skb->data; 1148 struct flowi4 fl4; 1149 struct rtable *rt; 1150 struct net *net = sock_net(sk); 1151 1152 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1153 rt = __ip_route_output_key(net, &fl4); 1154 if (!IS_ERR(rt)) { 1155 __ip_do_redirect(rt, skb, &fl4, false); 1156 ip_rt_put(rt); 1157 } 1158 } 1159 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1160 1161 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1162 { 1163 struct rtable *rt = (struct rtable *) dst; 1164 1165 /* All IPV4 dsts are created with ->obsolete set to the value 1166 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1167 * into this function always. 1168 * 1169 * When a PMTU/redirect information update invalidates a route, 1170 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1171 * DST_OBSOLETE_DEAD by dst_free(). 1172 */ 1173 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1174 return NULL; 1175 return dst; 1176 } 1177 1178 static void ipv4_link_failure(struct sk_buff *skb) 1179 { 1180 struct rtable *rt; 1181 1182 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1183 1184 rt = skb_rtable(skb); 1185 if (rt) 1186 dst_set_expires(&rt->dst, 0); 1187 } 1188 1189 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1190 { 1191 pr_debug("%s: %pI4 -> %pI4, %s\n", 1192 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1193 skb->dev ? skb->dev->name : "?"); 1194 kfree_skb(skb); 1195 WARN_ON(1); 1196 return 0; 1197 } 1198 1199 /* 1200 We do not cache source address of outgoing interface, 1201 because it is used only by IP RR, TS and SRR options, 1202 so that it out of fast path. 1203 1204 BTW remember: "addr" is allowed to be not aligned 1205 in IP options! 1206 */ 1207 1208 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1209 { 1210 __be32 src; 1211 1212 if (rt_is_output_route(rt)) 1213 src = ip_hdr(skb)->saddr; 1214 else { 1215 struct fib_result res; 1216 struct flowi4 fl4; 1217 struct iphdr *iph; 1218 1219 iph = ip_hdr(skb); 1220 1221 memset(&fl4, 0, sizeof(fl4)); 1222 fl4.daddr = iph->daddr; 1223 fl4.saddr = iph->saddr; 1224 fl4.flowi4_tos = RT_TOS(iph->tos); 1225 fl4.flowi4_oif = rt->dst.dev->ifindex; 1226 fl4.flowi4_iif = skb->dev->ifindex; 1227 fl4.flowi4_mark = skb->mark; 1228 1229 rcu_read_lock(); 1230 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1231 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1232 else 1233 src = inet_select_addr(rt->dst.dev, 1234 rt_nexthop(rt, iph->daddr), 1235 RT_SCOPE_UNIVERSE); 1236 rcu_read_unlock(); 1237 } 1238 memcpy(addr, &src, 4); 1239 } 1240 1241 #ifdef CONFIG_IP_ROUTE_CLASSID 1242 static void set_class_tag(struct rtable *rt, u32 tag) 1243 { 1244 if (!(rt->dst.tclassid & 0xFFFF)) 1245 rt->dst.tclassid |= tag & 0xFFFF; 1246 if (!(rt->dst.tclassid & 0xFFFF0000)) 1247 rt->dst.tclassid |= tag & 0xFFFF0000; 1248 } 1249 #endif 1250 1251 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1252 { 1253 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1254 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1255 ip_rt_min_advmss); 1256 1257 return min(advmss, IPV4_MAX_PMTU - header_size); 1258 } 1259 1260 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1261 { 1262 const struct rtable *rt = (const struct rtable *) dst; 1263 unsigned int mtu = rt->rt_pmtu; 1264 1265 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1266 mtu = dst_metric_raw(dst, RTAX_MTU); 1267 1268 if (mtu) 1269 return mtu; 1270 1271 mtu = READ_ONCE(dst->dev->mtu); 1272 1273 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { 1274 if (rt->rt_uses_gateway && mtu > 576) 1275 mtu = 576; 1276 } 1277 1278 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1279 1280 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1281 } 1282 1283 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1284 { 1285 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1286 struct fib_nh_exception *fnhe; 1287 u32 hval; 1288 1289 if (!hash) 1290 return NULL; 1291 1292 hval = fnhe_hashfun(daddr); 1293 1294 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1295 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1296 if (fnhe->fnhe_daddr == daddr) 1297 return fnhe; 1298 } 1299 return NULL; 1300 } 1301 1302 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1303 __be32 daddr, const bool do_cache) 1304 { 1305 bool ret = false; 1306 1307 spin_lock_bh(&fnhe_lock); 1308 1309 if (daddr == fnhe->fnhe_daddr) { 1310 struct rtable __rcu **porig; 1311 struct rtable *orig; 1312 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1313 1314 if (rt_is_input_route(rt)) 1315 porig = &fnhe->fnhe_rth_input; 1316 else 1317 porig = &fnhe->fnhe_rth_output; 1318 orig = rcu_dereference(*porig); 1319 1320 if (fnhe->fnhe_genid != genid) { 1321 fnhe->fnhe_genid = genid; 1322 fnhe->fnhe_gw = 0; 1323 fnhe->fnhe_pmtu = 0; 1324 fnhe->fnhe_expires = 0; 1325 fnhe_flush_routes(fnhe); 1326 orig = NULL; 1327 } 1328 fill_route_from_fnhe(rt, fnhe); 1329 if (!rt->rt_gateway) 1330 rt->rt_gateway = daddr; 1331 1332 if (do_cache) { 1333 dst_hold(&rt->dst); 1334 rcu_assign_pointer(*porig, rt); 1335 if (orig) { 1336 dst_dev_put(&orig->dst); 1337 dst_release(&orig->dst); 1338 } 1339 ret = true; 1340 } 1341 1342 fnhe->fnhe_stamp = jiffies; 1343 } 1344 spin_unlock_bh(&fnhe_lock); 1345 1346 return ret; 1347 } 1348 1349 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1350 { 1351 struct rtable *orig, *prev, **p; 1352 bool ret = true; 1353 1354 if (rt_is_input_route(rt)) { 1355 p = (struct rtable **)&nh->nh_rth_input; 1356 } else { 1357 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1358 } 1359 orig = *p; 1360 1361 /* hold dst before doing cmpxchg() to avoid race condition 1362 * on this dst 1363 */ 1364 dst_hold(&rt->dst); 1365 prev = cmpxchg(p, orig, rt); 1366 if (prev == orig) { 1367 if (orig) { 1368 dst_dev_put(&orig->dst); 1369 dst_release(&orig->dst); 1370 } 1371 } else { 1372 dst_release(&rt->dst); 1373 ret = false; 1374 } 1375 1376 return ret; 1377 } 1378 1379 struct uncached_list { 1380 spinlock_t lock; 1381 struct list_head head; 1382 }; 1383 1384 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1385 1386 static void rt_add_uncached_list(struct rtable *rt) 1387 { 1388 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1389 1390 rt->rt_uncached_list = ul; 1391 1392 spin_lock_bh(&ul->lock); 1393 list_add_tail(&rt->rt_uncached, &ul->head); 1394 spin_unlock_bh(&ul->lock); 1395 } 1396 1397 static void ipv4_dst_destroy(struct dst_entry *dst) 1398 { 1399 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst); 1400 struct rtable *rt = (struct rtable *) dst; 1401 1402 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt)) 1403 kfree(p); 1404 1405 if (!list_empty(&rt->rt_uncached)) { 1406 struct uncached_list *ul = rt->rt_uncached_list; 1407 1408 spin_lock_bh(&ul->lock); 1409 list_del(&rt->rt_uncached); 1410 spin_unlock_bh(&ul->lock); 1411 } 1412 } 1413 1414 void rt_flush_dev(struct net_device *dev) 1415 { 1416 struct net *net = dev_net(dev); 1417 struct rtable *rt; 1418 int cpu; 1419 1420 for_each_possible_cpu(cpu) { 1421 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1422 1423 spin_lock_bh(&ul->lock); 1424 list_for_each_entry(rt, &ul->head, rt_uncached) { 1425 if (rt->dst.dev != dev) 1426 continue; 1427 rt->dst.dev = net->loopback_dev; 1428 dev_hold(rt->dst.dev); 1429 dev_put(dev); 1430 } 1431 spin_unlock_bh(&ul->lock); 1432 } 1433 } 1434 1435 static bool rt_cache_valid(const struct rtable *rt) 1436 { 1437 return rt && 1438 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1439 !rt_is_expired(rt); 1440 } 1441 1442 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1443 const struct fib_result *res, 1444 struct fib_nh_exception *fnhe, 1445 struct fib_info *fi, u16 type, u32 itag, 1446 const bool do_cache) 1447 { 1448 bool cached = false; 1449 1450 if (fi) { 1451 struct fib_nh *nh = &FIB_RES_NH(*res); 1452 1453 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1454 rt->rt_gateway = nh->nh_gw; 1455 rt->rt_uses_gateway = 1; 1456 } 1457 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true); 1458 if (fi->fib_metrics != &dst_default_metrics) { 1459 rt->dst._metrics |= DST_METRICS_REFCOUNTED; 1460 refcount_inc(&fi->fib_metrics->refcnt); 1461 } 1462 #ifdef CONFIG_IP_ROUTE_CLASSID 1463 rt->dst.tclassid = nh->nh_tclassid; 1464 #endif 1465 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1466 if (unlikely(fnhe)) 1467 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1468 else if (do_cache) 1469 cached = rt_cache_route(nh, rt); 1470 if (unlikely(!cached)) { 1471 /* Routes we intend to cache in nexthop exception or 1472 * FIB nexthop have the DST_NOCACHE bit clear. 1473 * However, if we are unsuccessful at storing this 1474 * route into the cache we really need to set it. 1475 */ 1476 if (!rt->rt_gateway) 1477 rt->rt_gateway = daddr; 1478 rt_add_uncached_list(rt); 1479 } 1480 } else 1481 rt_add_uncached_list(rt); 1482 1483 #ifdef CONFIG_IP_ROUTE_CLASSID 1484 #ifdef CONFIG_IP_MULTIPLE_TABLES 1485 set_class_tag(rt, res->tclassid); 1486 #endif 1487 set_class_tag(rt, itag); 1488 #endif 1489 } 1490 1491 struct rtable *rt_dst_alloc(struct net_device *dev, 1492 unsigned int flags, u16 type, 1493 bool nopolicy, bool noxfrm, bool will_cache) 1494 { 1495 struct rtable *rt; 1496 1497 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1498 (will_cache ? 0 : DST_HOST) | 1499 (nopolicy ? DST_NOPOLICY : 0) | 1500 (noxfrm ? DST_NOXFRM : 0)); 1501 1502 if (rt) { 1503 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1504 rt->rt_flags = flags; 1505 rt->rt_type = type; 1506 rt->rt_is_input = 0; 1507 rt->rt_iif = 0; 1508 rt->rt_pmtu = 0; 1509 rt->rt_gateway = 0; 1510 rt->rt_uses_gateway = 0; 1511 rt->rt_table_id = 0; 1512 INIT_LIST_HEAD(&rt->rt_uncached); 1513 1514 rt->dst.output = ip_output; 1515 if (flags & RTCF_LOCAL) 1516 rt->dst.input = ip_local_deliver; 1517 } 1518 1519 return rt; 1520 } 1521 EXPORT_SYMBOL(rt_dst_alloc); 1522 1523 /* called in rcu_read_lock() section */ 1524 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1525 u8 tos, struct net_device *dev, 1526 struct in_device *in_dev, u32 *itag) 1527 { 1528 int err; 1529 1530 /* Primary sanity checks. */ 1531 if (!in_dev) 1532 return -EINVAL; 1533 1534 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1535 skb->protocol != htons(ETH_P_IP)) 1536 return -EINVAL; 1537 1538 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1539 return -EINVAL; 1540 1541 if (ipv4_is_zeronet(saddr)) { 1542 if (!ipv4_is_local_multicast(daddr)) 1543 return -EINVAL; 1544 } else { 1545 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1546 in_dev, itag); 1547 if (err < 0) 1548 return err; 1549 } 1550 return 0; 1551 } 1552 1553 /* called in rcu_read_lock() section */ 1554 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1555 u8 tos, struct net_device *dev, int our) 1556 { 1557 struct in_device *in_dev = __in_dev_get_rcu(dev); 1558 unsigned int flags = RTCF_MULTICAST; 1559 struct rtable *rth; 1560 u32 itag = 0; 1561 int err; 1562 1563 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1564 if (err) 1565 return err; 1566 1567 if (our) 1568 flags |= RTCF_LOCAL; 1569 1570 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1571 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1572 if (!rth) 1573 return -ENOBUFS; 1574 1575 #ifdef CONFIG_IP_ROUTE_CLASSID 1576 rth->dst.tclassid = itag; 1577 #endif 1578 rth->dst.output = ip_rt_bug; 1579 rth->rt_is_input= 1; 1580 1581 #ifdef CONFIG_IP_MROUTE 1582 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1583 rth->dst.input = ip_mr_input; 1584 #endif 1585 RT_CACHE_STAT_INC(in_slow_mc); 1586 1587 skb_dst_set(skb, &rth->dst); 1588 return 0; 1589 } 1590 1591 1592 static void ip_handle_martian_source(struct net_device *dev, 1593 struct in_device *in_dev, 1594 struct sk_buff *skb, 1595 __be32 daddr, 1596 __be32 saddr) 1597 { 1598 RT_CACHE_STAT_INC(in_martian_src); 1599 #ifdef CONFIG_IP_ROUTE_VERBOSE 1600 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1601 /* 1602 * RFC1812 recommendation, if source is martian, 1603 * the only hint is MAC header. 1604 */ 1605 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1606 &daddr, &saddr, dev->name); 1607 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1608 print_hex_dump(KERN_WARNING, "ll header: ", 1609 DUMP_PREFIX_OFFSET, 16, 1, 1610 skb_mac_header(skb), 1611 dev->hard_header_len, true); 1612 } 1613 } 1614 #endif 1615 } 1616 1617 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1618 { 1619 struct fnhe_hash_bucket *hash; 1620 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1621 u32 hval = fnhe_hashfun(daddr); 1622 1623 spin_lock_bh(&fnhe_lock); 1624 1625 hash = rcu_dereference_protected(nh->nh_exceptions, 1626 lockdep_is_held(&fnhe_lock)); 1627 hash += hval; 1628 1629 fnhe_p = &hash->chain; 1630 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1631 while (fnhe) { 1632 if (fnhe->fnhe_daddr == daddr) { 1633 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1634 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1635 fnhe_flush_routes(fnhe); 1636 kfree_rcu(fnhe, rcu); 1637 break; 1638 } 1639 fnhe_p = &fnhe->fnhe_next; 1640 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1641 lockdep_is_held(&fnhe_lock)); 1642 } 1643 1644 spin_unlock_bh(&fnhe_lock); 1645 } 1646 1647 static void set_lwt_redirect(struct rtable *rth) 1648 { 1649 if (lwtunnel_output_redirect(rth->dst.lwtstate)) { 1650 rth->dst.lwtstate->orig_output = rth->dst.output; 1651 rth->dst.output = lwtunnel_output; 1652 } 1653 1654 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 1655 rth->dst.lwtstate->orig_input = rth->dst.input; 1656 rth->dst.input = lwtunnel_input; 1657 } 1658 } 1659 1660 /* called in rcu_read_lock() section */ 1661 static int __mkroute_input(struct sk_buff *skb, 1662 const struct fib_result *res, 1663 struct in_device *in_dev, 1664 __be32 daddr, __be32 saddr, u32 tos) 1665 { 1666 struct fib_nh_exception *fnhe; 1667 struct rtable *rth; 1668 int err; 1669 struct in_device *out_dev; 1670 bool do_cache; 1671 u32 itag = 0; 1672 1673 /* get a working reference to the output device */ 1674 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1675 if (!out_dev) { 1676 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1677 return -EINVAL; 1678 } 1679 1680 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1681 in_dev->dev, in_dev, &itag); 1682 if (err < 0) { 1683 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1684 saddr); 1685 1686 goto cleanup; 1687 } 1688 1689 do_cache = res->fi && !itag; 1690 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1691 skb->protocol == htons(ETH_P_IP) && 1692 (IN_DEV_SHARED_MEDIA(out_dev) || 1693 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1694 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1695 1696 if (skb->protocol != htons(ETH_P_IP)) { 1697 /* Not IP (i.e. ARP). Do not create route, if it is 1698 * invalid for proxy arp. DNAT routes are always valid. 1699 * 1700 * Proxy arp feature have been extended to allow, ARP 1701 * replies back to the same interface, to support 1702 * Private VLAN switch technologies. See arp.c. 1703 */ 1704 if (out_dev == in_dev && 1705 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1706 err = -EINVAL; 1707 goto cleanup; 1708 } 1709 } 1710 1711 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1712 if (do_cache) { 1713 if (fnhe) { 1714 rth = rcu_dereference(fnhe->fnhe_rth_input); 1715 if (rth && rth->dst.expires && 1716 time_after(jiffies, rth->dst.expires)) { 1717 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1718 fnhe = NULL; 1719 } else { 1720 goto rt_cache; 1721 } 1722 } 1723 1724 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1725 1726 rt_cache: 1727 if (rt_cache_valid(rth)) { 1728 skb_dst_set_noref(skb, &rth->dst); 1729 goto out; 1730 } 1731 } 1732 1733 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1734 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1735 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1736 if (!rth) { 1737 err = -ENOBUFS; 1738 goto cleanup; 1739 } 1740 1741 rth->rt_is_input = 1; 1742 if (res->table) 1743 rth->rt_table_id = res->table->tb_id; 1744 RT_CACHE_STAT_INC(in_slow_tot); 1745 1746 rth->dst.input = ip_forward; 1747 1748 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1749 do_cache); 1750 set_lwt_redirect(rth); 1751 skb_dst_set(skb, &rth->dst); 1752 out: 1753 err = 0; 1754 cleanup: 1755 return err; 1756 } 1757 1758 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1759 /* To make ICMP packets follow the right flow, the multipath hash is 1760 * calculated from the inner IP addresses. 1761 */ 1762 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1763 struct flow_keys *hash_keys) 1764 { 1765 const struct iphdr *outer_iph = ip_hdr(skb); 1766 const struct iphdr *inner_iph; 1767 const struct icmphdr *icmph; 1768 struct iphdr _inner_iph; 1769 struct icmphdr _icmph; 1770 1771 hash_keys->addrs.v4addrs.src = outer_iph->saddr; 1772 hash_keys->addrs.v4addrs.dst = outer_iph->daddr; 1773 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1774 return; 1775 1776 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1777 return; 1778 1779 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1780 &_icmph); 1781 if (!icmph) 1782 return; 1783 1784 if (icmph->type != ICMP_DEST_UNREACH && 1785 icmph->type != ICMP_REDIRECT && 1786 icmph->type != ICMP_TIME_EXCEEDED && 1787 icmph->type != ICMP_PARAMETERPROB) 1788 return; 1789 1790 inner_iph = skb_header_pointer(skb, 1791 outer_iph->ihl * 4 + sizeof(_icmph), 1792 sizeof(_inner_iph), &_inner_iph); 1793 if (!inner_iph) 1794 return; 1795 hash_keys->addrs.v4addrs.src = inner_iph->saddr; 1796 hash_keys->addrs.v4addrs.dst = inner_iph->daddr; 1797 } 1798 1799 /* if skb is set it will be used and fl4 can be NULL */ 1800 int fib_multipath_hash(const struct fib_info *fi, const struct flowi4 *fl4, 1801 const struct sk_buff *skb) 1802 { 1803 struct net *net = fi->fib_net; 1804 struct flow_keys hash_keys; 1805 u32 mhash; 1806 1807 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1808 case 0: 1809 memset(&hash_keys, 0, sizeof(hash_keys)); 1810 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1811 if (skb) { 1812 ip_multipath_l3_keys(skb, &hash_keys); 1813 } else { 1814 hash_keys.addrs.v4addrs.src = fl4->saddr; 1815 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1816 } 1817 break; 1818 case 1: 1819 /* skb is currently provided only when forwarding */ 1820 if (skb) { 1821 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1822 struct flow_keys keys; 1823 1824 /* short-circuit if we already have L4 hash present */ 1825 if (skb->l4_hash) 1826 return skb_get_hash_raw(skb) >> 1; 1827 memset(&hash_keys, 0, sizeof(hash_keys)); 1828 skb_flow_dissect_flow_keys(skb, &keys, flag); 1829 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1830 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1831 hash_keys.ports.src = keys.ports.src; 1832 hash_keys.ports.dst = keys.ports.dst; 1833 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1834 } else { 1835 memset(&hash_keys, 0, sizeof(hash_keys)); 1836 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1837 hash_keys.addrs.v4addrs.src = fl4->saddr; 1838 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1839 hash_keys.ports.src = fl4->fl4_sport; 1840 hash_keys.ports.dst = fl4->fl4_dport; 1841 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1842 } 1843 break; 1844 } 1845 mhash = flow_hash_from_keys(&hash_keys); 1846 1847 return mhash >> 1; 1848 } 1849 EXPORT_SYMBOL_GPL(fib_multipath_hash); 1850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1851 1852 static int ip_mkroute_input(struct sk_buff *skb, 1853 struct fib_result *res, 1854 struct in_device *in_dev, 1855 __be32 daddr, __be32 saddr, u32 tos) 1856 { 1857 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1858 if (res->fi && res->fi->fib_nhs > 1) { 1859 int h = fib_multipath_hash(res->fi, NULL, skb); 1860 1861 fib_select_multipath(res, h); 1862 } 1863 #endif 1864 1865 /* create a routing cache entry */ 1866 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1867 } 1868 1869 /* 1870 * NOTE. We drop all the packets that has local source 1871 * addresses, because every properly looped back packet 1872 * must have correct destination already attached by output routine. 1873 * 1874 * Such approach solves two big problems: 1875 * 1. Not simplex devices are handled properly. 1876 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1877 * called with rcu_read_lock() 1878 */ 1879 1880 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1881 u8 tos, struct net_device *dev, 1882 struct fib_result *res) 1883 { 1884 struct in_device *in_dev = __in_dev_get_rcu(dev); 1885 struct ip_tunnel_info *tun_info; 1886 struct flowi4 fl4; 1887 unsigned int flags = 0; 1888 u32 itag = 0; 1889 struct rtable *rth; 1890 int err = -EINVAL; 1891 struct net *net = dev_net(dev); 1892 bool do_cache; 1893 1894 /* IP on this device is disabled. */ 1895 1896 if (!in_dev) 1897 goto out; 1898 1899 /* Check for the most weird martians, which can be not detected 1900 by fib_lookup. 1901 */ 1902 1903 tun_info = skb_tunnel_info(skb); 1904 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1905 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1906 else 1907 fl4.flowi4_tun_key.tun_id = 0; 1908 skb_dst_drop(skb); 1909 1910 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1911 goto martian_source; 1912 1913 res->fi = NULL; 1914 res->table = NULL; 1915 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1916 goto brd_input; 1917 1918 /* Accept zero addresses only to limited broadcast; 1919 * I even do not know to fix it or not. Waiting for complains :-) 1920 */ 1921 if (ipv4_is_zeronet(saddr)) 1922 goto martian_source; 1923 1924 if (ipv4_is_zeronet(daddr)) 1925 goto martian_destination; 1926 1927 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1928 * and call it once if daddr or/and saddr are loopback addresses 1929 */ 1930 if (ipv4_is_loopback(daddr)) { 1931 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1932 goto martian_destination; 1933 } else if (ipv4_is_loopback(saddr)) { 1934 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1935 goto martian_source; 1936 } 1937 1938 /* 1939 * Now we are ready to route packet. 1940 */ 1941 fl4.flowi4_oif = 0; 1942 fl4.flowi4_iif = dev->ifindex; 1943 fl4.flowi4_mark = skb->mark; 1944 fl4.flowi4_tos = tos; 1945 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1946 fl4.flowi4_flags = 0; 1947 fl4.daddr = daddr; 1948 fl4.saddr = saddr; 1949 fl4.flowi4_uid = sock_net_uid(net, NULL); 1950 err = fib_lookup(net, &fl4, res, 0); 1951 if (err != 0) { 1952 if (!IN_DEV_FORWARD(in_dev)) 1953 err = -EHOSTUNREACH; 1954 goto no_route; 1955 } 1956 1957 if (res->type == RTN_BROADCAST) 1958 goto brd_input; 1959 1960 if (res->type == RTN_LOCAL) { 1961 err = fib_validate_source(skb, saddr, daddr, tos, 1962 0, dev, in_dev, &itag); 1963 if (err < 0) 1964 goto martian_source; 1965 goto local_input; 1966 } 1967 1968 if (!IN_DEV_FORWARD(in_dev)) { 1969 err = -EHOSTUNREACH; 1970 goto no_route; 1971 } 1972 if (res->type != RTN_UNICAST) 1973 goto martian_destination; 1974 1975 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1976 out: return err; 1977 1978 brd_input: 1979 if (skb->protocol != htons(ETH_P_IP)) 1980 goto e_inval; 1981 1982 if (!ipv4_is_zeronet(saddr)) { 1983 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1984 in_dev, &itag); 1985 if (err < 0) 1986 goto martian_source; 1987 } 1988 flags |= RTCF_BROADCAST; 1989 res->type = RTN_BROADCAST; 1990 RT_CACHE_STAT_INC(in_brd); 1991 1992 local_input: 1993 do_cache = false; 1994 if (res->fi) { 1995 if (!itag) { 1996 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1997 if (rt_cache_valid(rth)) { 1998 skb_dst_set_noref(skb, &rth->dst); 1999 err = 0; 2000 goto out; 2001 } 2002 do_cache = true; 2003 } 2004 } 2005 2006 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2007 flags | RTCF_LOCAL, res->type, 2008 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2009 if (!rth) 2010 goto e_nobufs; 2011 2012 rth->dst.output= ip_rt_bug; 2013 #ifdef CONFIG_IP_ROUTE_CLASSID 2014 rth->dst.tclassid = itag; 2015 #endif 2016 rth->rt_is_input = 1; 2017 if (res->table) 2018 rth->rt_table_id = res->table->tb_id; 2019 2020 RT_CACHE_STAT_INC(in_slow_tot); 2021 if (res->type == RTN_UNREACHABLE) { 2022 rth->dst.input= ip_error; 2023 rth->dst.error= -err; 2024 rth->rt_flags &= ~RTCF_LOCAL; 2025 } 2026 2027 if (do_cache) { 2028 struct fib_nh *nh = &FIB_RES_NH(*res); 2029 2030 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 2031 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2032 WARN_ON(rth->dst.input == lwtunnel_input); 2033 rth->dst.lwtstate->orig_input = rth->dst.input; 2034 rth->dst.input = lwtunnel_input; 2035 } 2036 2037 if (unlikely(!rt_cache_route(nh, rth))) 2038 rt_add_uncached_list(rth); 2039 } 2040 skb_dst_set(skb, &rth->dst); 2041 err = 0; 2042 goto out; 2043 2044 no_route: 2045 RT_CACHE_STAT_INC(in_no_route); 2046 res->type = RTN_UNREACHABLE; 2047 res->fi = NULL; 2048 res->table = NULL; 2049 goto local_input; 2050 2051 /* 2052 * Do not cache martian addresses: they should be logged (RFC1812) 2053 */ 2054 martian_destination: 2055 RT_CACHE_STAT_INC(in_martian_dst); 2056 #ifdef CONFIG_IP_ROUTE_VERBOSE 2057 if (IN_DEV_LOG_MARTIANS(in_dev)) 2058 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2059 &daddr, &saddr, dev->name); 2060 #endif 2061 2062 e_inval: 2063 err = -EINVAL; 2064 goto out; 2065 2066 e_nobufs: 2067 err = -ENOBUFS; 2068 goto out; 2069 2070 martian_source: 2071 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2072 goto out; 2073 } 2074 2075 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2076 u8 tos, struct net_device *dev) 2077 { 2078 struct fib_result res; 2079 int err; 2080 2081 tos &= IPTOS_RT_MASK; 2082 rcu_read_lock(); 2083 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2084 rcu_read_unlock(); 2085 2086 return err; 2087 } 2088 EXPORT_SYMBOL(ip_route_input_noref); 2089 2090 /* called with rcu_read_lock held */ 2091 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2092 u8 tos, struct net_device *dev, struct fib_result *res) 2093 { 2094 /* Multicast recognition logic is moved from route cache to here. 2095 The problem was that too many Ethernet cards have broken/missing 2096 hardware multicast filters :-( As result the host on multicasting 2097 network acquires a lot of useless route cache entries, sort of 2098 SDR messages from all the world. Now we try to get rid of them. 2099 Really, provided software IP multicast filter is organized 2100 reasonably (at least, hashed), it does not result in a slowdown 2101 comparing with route cache reject entries. 2102 Note, that multicast routers are not affected, because 2103 route cache entry is created eventually. 2104 */ 2105 if (ipv4_is_multicast(daddr)) { 2106 struct in_device *in_dev = __in_dev_get_rcu(dev); 2107 int our = 0; 2108 int err = -EINVAL; 2109 2110 if (in_dev) 2111 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2112 ip_hdr(skb)->protocol); 2113 2114 /* check l3 master if no match yet */ 2115 if ((!in_dev || !our) && netif_is_l3_slave(dev)) { 2116 struct in_device *l3_in_dev; 2117 2118 l3_in_dev = __in_dev_get_rcu(skb->dev); 2119 if (l3_in_dev) 2120 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2121 ip_hdr(skb)->protocol); 2122 } 2123 2124 if (our 2125 #ifdef CONFIG_IP_MROUTE 2126 || 2127 (!ipv4_is_local_multicast(daddr) && 2128 IN_DEV_MFORWARD(in_dev)) 2129 #endif 2130 ) { 2131 err = ip_route_input_mc(skb, daddr, saddr, 2132 tos, dev, our); 2133 } 2134 return err; 2135 } 2136 2137 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2138 } 2139 2140 /* called with rcu_read_lock() */ 2141 static struct rtable *__mkroute_output(const struct fib_result *res, 2142 const struct flowi4 *fl4, int orig_oif, 2143 struct net_device *dev_out, 2144 unsigned int flags) 2145 { 2146 struct fib_info *fi = res->fi; 2147 struct fib_nh_exception *fnhe; 2148 struct in_device *in_dev; 2149 u16 type = res->type; 2150 struct rtable *rth; 2151 bool do_cache; 2152 2153 in_dev = __in_dev_get_rcu(dev_out); 2154 if (!in_dev) 2155 return ERR_PTR(-EINVAL); 2156 2157 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2158 if (ipv4_is_loopback(fl4->saddr) && 2159 !(dev_out->flags & IFF_LOOPBACK) && 2160 !netif_is_l3_master(dev_out)) 2161 return ERR_PTR(-EINVAL); 2162 2163 if (ipv4_is_lbcast(fl4->daddr)) 2164 type = RTN_BROADCAST; 2165 else if (ipv4_is_multicast(fl4->daddr)) 2166 type = RTN_MULTICAST; 2167 else if (ipv4_is_zeronet(fl4->daddr)) 2168 return ERR_PTR(-EINVAL); 2169 2170 if (dev_out->flags & IFF_LOOPBACK) 2171 flags |= RTCF_LOCAL; 2172 2173 do_cache = true; 2174 if (type == RTN_BROADCAST) { 2175 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2176 fi = NULL; 2177 } else if (type == RTN_MULTICAST) { 2178 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2179 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2180 fl4->flowi4_proto)) 2181 flags &= ~RTCF_LOCAL; 2182 else 2183 do_cache = false; 2184 /* If multicast route do not exist use 2185 * default one, but do not gateway in this case. 2186 * Yes, it is hack. 2187 */ 2188 if (fi && res->prefixlen < 4) 2189 fi = NULL; 2190 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2191 (orig_oif != dev_out->ifindex)) { 2192 /* For local routes that require a particular output interface 2193 * we do not want to cache the result. Caching the result 2194 * causes incorrect behaviour when there are multiple source 2195 * addresses on the interface, the end result being that if the 2196 * intended recipient is waiting on that interface for the 2197 * packet he won't receive it because it will be delivered on 2198 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2199 * be set to the loopback interface as well. 2200 */ 2201 fi = NULL; 2202 } 2203 2204 fnhe = NULL; 2205 do_cache &= fi != NULL; 2206 if (do_cache) { 2207 struct rtable __rcu **prth; 2208 struct fib_nh *nh = &FIB_RES_NH(*res); 2209 2210 fnhe = find_exception(nh, fl4->daddr); 2211 if (fnhe) { 2212 prth = &fnhe->fnhe_rth_output; 2213 rth = rcu_dereference(*prth); 2214 if (rth && rth->dst.expires && 2215 time_after(jiffies, rth->dst.expires)) { 2216 ip_del_fnhe(nh, fl4->daddr); 2217 fnhe = NULL; 2218 } else { 2219 goto rt_cache; 2220 } 2221 } 2222 2223 if (unlikely(fl4->flowi4_flags & 2224 FLOWI_FLAG_KNOWN_NH && 2225 !(nh->nh_gw && 2226 nh->nh_scope == RT_SCOPE_LINK))) { 2227 do_cache = false; 2228 goto add; 2229 } 2230 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2231 rth = rcu_dereference(*prth); 2232 2233 rt_cache: 2234 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2235 return rth; 2236 } 2237 2238 add: 2239 rth = rt_dst_alloc(dev_out, flags, type, 2240 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2241 IN_DEV_CONF_GET(in_dev, NOXFRM), 2242 do_cache); 2243 if (!rth) 2244 return ERR_PTR(-ENOBUFS); 2245 2246 rth->rt_iif = orig_oif; 2247 if (res->table) 2248 rth->rt_table_id = res->table->tb_id; 2249 2250 RT_CACHE_STAT_INC(out_slow_tot); 2251 2252 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2253 if (flags & RTCF_LOCAL && 2254 !(dev_out->flags & IFF_LOOPBACK)) { 2255 rth->dst.output = ip_mc_output; 2256 RT_CACHE_STAT_INC(out_slow_mc); 2257 } 2258 #ifdef CONFIG_IP_MROUTE 2259 if (type == RTN_MULTICAST) { 2260 if (IN_DEV_MFORWARD(in_dev) && 2261 !ipv4_is_local_multicast(fl4->daddr)) { 2262 rth->dst.input = ip_mr_input; 2263 rth->dst.output = ip_mc_output; 2264 } 2265 } 2266 #endif 2267 } 2268 2269 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2270 set_lwt_redirect(rth); 2271 2272 return rth; 2273 } 2274 2275 /* 2276 * Major route resolver routine. 2277 */ 2278 2279 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2280 const struct sk_buff *skb) 2281 { 2282 __u8 tos = RT_FL_TOS(fl4); 2283 struct fib_result res; 2284 struct rtable *rth; 2285 2286 res.tclassid = 0; 2287 res.fi = NULL; 2288 res.table = NULL; 2289 2290 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2291 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2292 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2293 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2294 2295 rcu_read_lock(); 2296 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2297 rcu_read_unlock(); 2298 2299 return rth; 2300 } 2301 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2302 2303 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2304 struct fib_result *res, 2305 const struct sk_buff *skb) 2306 { 2307 struct net_device *dev_out = NULL; 2308 int orig_oif = fl4->flowi4_oif; 2309 unsigned int flags = 0; 2310 struct rtable *rth; 2311 int err = -ENETUNREACH; 2312 2313 if (fl4->saddr) { 2314 rth = ERR_PTR(-EINVAL); 2315 if (ipv4_is_multicast(fl4->saddr) || 2316 ipv4_is_lbcast(fl4->saddr) || 2317 ipv4_is_zeronet(fl4->saddr)) 2318 goto out; 2319 2320 /* I removed check for oif == dev_out->oif here. 2321 It was wrong for two reasons: 2322 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2323 is assigned to multiple interfaces. 2324 2. Moreover, we are allowed to send packets with saddr 2325 of another iface. --ANK 2326 */ 2327 2328 if (fl4->flowi4_oif == 0 && 2329 (ipv4_is_multicast(fl4->daddr) || 2330 ipv4_is_lbcast(fl4->daddr))) { 2331 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2332 dev_out = __ip_dev_find(net, fl4->saddr, false); 2333 if (!dev_out) 2334 goto out; 2335 2336 /* Special hack: user can direct multicasts 2337 and limited broadcast via necessary interface 2338 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2339 This hack is not just for fun, it allows 2340 vic,vat and friends to work. 2341 They bind socket to loopback, set ttl to zero 2342 and expect that it will work. 2343 From the viewpoint of routing cache they are broken, 2344 because we are not allowed to build multicast path 2345 with loopback source addr (look, routing cache 2346 cannot know, that ttl is zero, so that packet 2347 will not leave this host and route is valid). 2348 Luckily, this hack is good workaround. 2349 */ 2350 2351 fl4->flowi4_oif = dev_out->ifindex; 2352 goto make_route; 2353 } 2354 2355 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2356 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2357 if (!__ip_dev_find(net, fl4->saddr, false)) 2358 goto out; 2359 } 2360 } 2361 2362 2363 if (fl4->flowi4_oif) { 2364 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2365 rth = ERR_PTR(-ENODEV); 2366 if (!dev_out) 2367 goto out; 2368 2369 /* RACE: Check return value of inet_select_addr instead. */ 2370 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2371 rth = ERR_PTR(-ENETUNREACH); 2372 goto out; 2373 } 2374 if (ipv4_is_local_multicast(fl4->daddr) || 2375 ipv4_is_lbcast(fl4->daddr) || 2376 fl4->flowi4_proto == IPPROTO_IGMP) { 2377 if (!fl4->saddr) 2378 fl4->saddr = inet_select_addr(dev_out, 0, 2379 RT_SCOPE_LINK); 2380 goto make_route; 2381 } 2382 if (!fl4->saddr) { 2383 if (ipv4_is_multicast(fl4->daddr)) 2384 fl4->saddr = inet_select_addr(dev_out, 0, 2385 fl4->flowi4_scope); 2386 else if (!fl4->daddr) 2387 fl4->saddr = inet_select_addr(dev_out, 0, 2388 RT_SCOPE_HOST); 2389 } 2390 } 2391 2392 if (!fl4->daddr) { 2393 fl4->daddr = fl4->saddr; 2394 if (!fl4->daddr) 2395 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2396 dev_out = net->loopback_dev; 2397 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2398 res->type = RTN_LOCAL; 2399 flags |= RTCF_LOCAL; 2400 goto make_route; 2401 } 2402 2403 err = fib_lookup(net, fl4, res, 0); 2404 if (err) { 2405 res->fi = NULL; 2406 res->table = NULL; 2407 if (fl4->flowi4_oif && 2408 (ipv4_is_multicast(fl4->daddr) || 2409 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2410 /* Apparently, routing tables are wrong. Assume, 2411 that the destination is on link. 2412 2413 WHY? DW. 2414 Because we are allowed to send to iface 2415 even if it has NO routes and NO assigned 2416 addresses. When oif is specified, routing 2417 tables are looked up with only one purpose: 2418 to catch if destination is gatewayed, rather than 2419 direct. Moreover, if MSG_DONTROUTE is set, 2420 we send packet, ignoring both routing tables 2421 and ifaddr state. --ANK 2422 2423 2424 We could make it even if oif is unknown, 2425 likely IPv6, but we do not. 2426 */ 2427 2428 if (fl4->saddr == 0) 2429 fl4->saddr = inet_select_addr(dev_out, 0, 2430 RT_SCOPE_LINK); 2431 res->type = RTN_UNICAST; 2432 goto make_route; 2433 } 2434 rth = ERR_PTR(err); 2435 goto out; 2436 } 2437 2438 if (res->type == RTN_LOCAL) { 2439 if (!fl4->saddr) { 2440 if (res->fi->fib_prefsrc) 2441 fl4->saddr = res->fi->fib_prefsrc; 2442 else 2443 fl4->saddr = fl4->daddr; 2444 } 2445 2446 /* L3 master device is the loopback for that domain */ 2447 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2448 net->loopback_dev; 2449 2450 /* make sure orig_oif points to fib result device even 2451 * though packet rx/tx happens over loopback or l3mdev 2452 */ 2453 orig_oif = FIB_RES_OIF(*res); 2454 2455 fl4->flowi4_oif = dev_out->ifindex; 2456 flags |= RTCF_LOCAL; 2457 goto make_route; 2458 } 2459 2460 fib_select_path(net, res, fl4, skb); 2461 2462 dev_out = FIB_RES_DEV(*res); 2463 fl4->flowi4_oif = dev_out->ifindex; 2464 2465 2466 make_route: 2467 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2468 2469 out: 2470 return rth; 2471 } 2472 2473 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2474 { 2475 return NULL; 2476 } 2477 2478 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2479 { 2480 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2481 2482 return mtu ? : dst->dev->mtu; 2483 } 2484 2485 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2486 struct sk_buff *skb, u32 mtu) 2487 { 2488 } 2489 2490 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2491 struct sk_buff *skb) 2492 { 2493 } 2494 2495 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2496 unsigned long old) 2497 { 2498 return NULL; 2499 } 2500 2501 static struct dst_ops ipv4_dst_blackhole_ops = { 2502 .family = AF_INET, 2503 .check = ipv4_blackhole_dst_check, 2504 .mtu = ipv4_blackhole_mtu, 2505 .default_advmss = ipv4_default_advmss, 2506 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2507 .redirect = ipv4_rt_blackhole_redirect, 2508 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2509 .neigh_lookup = ipv4_neigh_lookup, 2510 }; 2511 2512 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2513 { 2514 struct rtable *ort = (struct rtable *) dst_orig; 2515 struct rtable *rt; 2516 2517 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2518 if (rt) { 2519 struct dst_entry *new = &rt->dst; 2520 2521 new->__use = 1; 2522 new->input = dst_discard; 2523 new->output = dst_discard_out; 2524 2525 new->dev = net->loopback_dev; 2526 if (new->dev) 2527 dev_hold(new->dev); 2528 2529 rt->rt_is_input = ort->rt_is_input; 2530 rt->rt_iif = ort->rt_iif; 2531 rt->rt_pmtu = ort->rt_pmtu; 2532 2533 rt->rt_genid = rt_genid_ipv4(net); 2534 rt->rt_flags = ort->rt_flags; 2535 rt->rt_type = ort->rt_type; 2536 rt->rt_gateway = ort->rt_gateway; 2537 rt->rt_uses_gateway = ort->rt_uses_gateway; 2538 2539 INIT_LIST_HEAD(&rt->rt_uncached); 2540 } 2541 2542 dst_release(dst_orig); 2543 2544 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2545 } 2546 2547 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2548 const struct sock *sk) 2549 { 2550 struct rtable *rt = __ip_route_output_key(net, flp4); 2551 2552 if (IS_ERR(rt)) 2553 return rt; 2554 2555 if (flp4->flowi4_proto) 2556 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2557 flowi4_to_flowi(flp4), 2558 sk, 0); 2559 2560 return rt; 2561 } 2562 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2563 2564 /* called with rcu_read_lock held */ 2565 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2566 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2567 u32 seq) 2568 { 2569 struct rtable *rt = skb_rtable(skb); 2570 struct rtmsg *r; 2571 struct nlmsghdr *nlh; 2572 unsigned long expires = 0; 2573 u32 error; 2574 u32 metrics[RTAX_MAX]; 2575 2576 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0); 2577 if (!nlh) 2578 return -EMSGSIZE; 2579 2580 r = nlmsg_data(nlh); 2581 r->rtm_family = AF_INET; 2582 r->rtm_dst_len = 32; 2583 r->rtm_src_len = 0; 2584 r->rtm_tos = fl4->flowi4_tos; 2585 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2586 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2587 goto nla_put_failure; 2588 r->rtm_type = rt->rt_type; 2589 r->rtm_scope = RT_SCOPE_UNIVERSE; 2590 r->rtm_protocol = RTPROT_UNSPEC; 2591 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2592 if (rt->rt_flags & RTCF_NOTIFY) 2593 r->rtm_flags |= RTM_F_NOTIFY; 2594 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2595 r->rtm_flags |= RTCF_DOREDIRECT; 2596 2597 if (nla_put_in_addr(skb, RTA_DST, dst)) 2598 goto nla_put_failure; 2599 if (src) { 2600 r->rtm_src_len = 32; 2601 if (nla_put_in_addr(skb, RTA_SRC, src)) 2602 goto nla_put_failure; 2603 } 2604 if (rt->dst.dev && 2605 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2606 goto nla_put_failure; 2607 #ifdef CONFIG_IP_ROUTE_CLASSID 2608 if (rt->dst.tclassid && 2609 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2610 goto nla_put_failure; 2611 #endif 2612 if (!rt_is_input_route(rt) && 2613 fl4->saddr != src) { 2614 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2615 goto nla_put_failure; 2616 } 2617 if (rt->rt_uses_gateway && 2618 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2619 goto nla_put_failure; 2620 2621 expires = rt->dst.expires; 2622 if (expires) { 2623 unsigned long now = jiffies; 2624 2625 if (time_before(now, expires)) 2626 expires -= now; 2627 else 2628 expires = 0; 2629 } 2630 2631 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2632 if (rt->rt_pmtu && expires) 2633 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2634 if (rtnetlink_put_metrics(skb, metrics) < 0) 2635 goto nla_put_failure; 2636 2637 if (fl4->flowi4_mark && 2638 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2639 goto nla_put_failure; 2640 2641 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2642 nla_put_u32(skb, RTA_UID, 2643 from_kuid_munged(current_user_ns(), fl4->flowi4_uid))) 2644 goto nla_put_failure; 2645 2646 error = rt->dst.error; 2647 2648 if (rt_is_input_route(rt)) { 2649 #ifdef CONFIG_IP_MROUTE 2650 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2651 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2652 int err = ipmr_get_route(net, skb, 2653 fl4->saddr, fl4->daddr, 2654 r, portid); 2655 2656 if (err <= 0) { 2657 if (err == 0) 2658 return 0; 2659 goto nla_put_failure; 2660 } 2661 } else 2662 #endif 2663 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2664 goto nla_put_failure; 2665 } 2666 2667 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2668 goto nla_put_failure; 2669 2670 nlmsg_end(skb, nlh); 2671 return 0; 2672 2673 nla_put_failure: 2674 nlmsg_cancel(skb, nlh); 2675 return -EMSGSIZE; 2676 } 2677 2678 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 2679 struct netlink_ext_ack *extack) 2680 { 2681 struct net *net = sock_net(in_skb->sk); 2682 struct rtmsg *rtm; 2683 struct nlattr *tb[RTA_MAX+1]; 2684 struct fib_result res = {}; 2685 struct rtable *rt = NULL; 2686 struct flowi4 fl4; 2687 __be32 dst = 0; 2688 __be32 src = 0; 2689 u32 iif; 2690 int err; 2691 int mark; 2692 struct sk_buff *skb; 2693 u32 table_id = RT_TABLE_MAIN; 2694 kuid_t uid; 2695 2696 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy, 2697 extack); 2698 if (err < 0) 2699 goto errout; 2700 2701 rtm = nlmsg_data(nlh); 2702 2703 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2704 if (!skb) { 2705 err = -ENOBUFS; 2706 goto errout; 2707 } 2708 2709 /* Reserve room for dummy headers, this skb can pass 2710 through good chunk of routing engine. 2711 */ 2712 skb_reset_mac_header(skb); 2713 skb_reset_network_header(skb); 2714 2715 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2716 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2717 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2718 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2719 if (tb[RTA_UID]) 2720 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 2721 else 2722 uid = (iif ? INVALID_UID : current_uid()); 2723 2724 /* Bugfix: need to give ip_route_input enough of an IP header to 2725 * not gag. 2726 */ 2727 ip_hdr(skb)->protocol = IPPROTO_UDP; 2728 ip_hdr(skb)->saddr = src; 2729 ip_hdr(skb)->daddr = dst; 2730 2731 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2732 2733 memset(&fl4, 0, sizeof(fl4)); 2734 fl4.daddr = dst; 2735 fl4.saddr = src; 2736 fl4.flowi4_tos = rtm->rtm_tos; 2737 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2738 fl4.flowi4_mark = mark; 2739 fl4.flowi4_uid = uid; 2740 2741 rcu_read_lock(); 2742 2743 if (iif) { 2744 struct net_device *dev; 2745 2746 dev = dev_get_by_index_rcu(net, iif); 2747 if (!dev) { 2748 err = -ENODEV; 2749 goto errout_free; 2750 } 2751 2752 skb->protocol = htons(ETH_P_IP); 2753 skb->dev = dev; 2754 skb->mark = mark; 2755 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 2756 dev, &res); 2757 2758 rt = skb_rtable(skb); 2759 if (err == 0 && rt->dst.error) 2760 err = -rt->dst.error; 2761 } else { 2762 fl4.flowi4_iif = LOOPBACK_IFINDEX; 2763 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 2764 err = 0; 2765 if (IS_ERR(rt)) 2766 err = PTR_ERR(rt); 2767 else 2768 skb_dst_set(skb, &rt->dst); 2769 } 2770 2771 if (err) 2772 goto errout_free; 2773 2774 if (rtm->rtm_flags & RTM_F_NOTIFY) 2775 rt->rt_flags |= RTCF_NOTIFY; 2776 2777 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2778 table_id = rt->rt_table_id; 2779 2780 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 2781 if (!res.fi) { 2782 err = fib_props[res.type].error; 2783 if (!err) 2784 err = -EHOSTUNREACH; 2785 goto errout_free; 2786 } 2787 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 2788 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 2789 rt->rt_type, res.prefix, res.prefixlen, 2790 fl4.flowi4_tos, res.fi, 0); 2791 } else { 2792 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2793 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq); 2794 } 2795 if (err < 0) 2796 goto errout_free; 2797 2798 rcu_read_unlock(); 2799 2800 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2801 errout: 2802 return err; 2803 2804 errout_free: 2805 rcu_read_unlock(); 2806 kfree_skb(skb); 2807 goto errout; 2808 } 2809 2810 void ip_rt_multicast_event(struct in_device *in_dev) 2811 { 2812 rt_cache_flush(dev_net(in_dev->dev)); 2813 } 2814 2815 #ifdef CONFIG_SYSCTL 2816 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2817 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2818 static int ip_rt_gc_elasticity __read_mostly = 8; 2819 2820 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2821 void __user *buffer, 2822 size_t *lenp, loff_t *ppos) 2823 { 2824 struct net *net = (struct net *)__ctl->extra1; 2825 2826 if (write) { 2827 rt_cache_flush(net); 2828 fnhe_genid_bump(net); 2829 return 0; 2830 } 2831 2832 return -EINVAL; 2833 } 2834 2835 static struct ctl_table ipv4_route_table[] = { 2836 { 2837 .procname = "gc_thresh", 2838 .data = &ipv4_dst_ops.gc_thresh, 2839 .maxlen = sizeof(int), 2840 .mode = 0644, 2841 .proc_handler = proc_dointvec, 2842 }, 2843 { 2844 .procname = "max_size", 2845 .data = &ip_rt_max_size, 2846 .maxlen = sizeof(int), 2847 .mode = 0644, 2848 .proc_handler = proc_dointvec, 2849 }, 2850 { 2851 /* Deprecated. Use gc_min_interval_ms */ 2852 2853 .procname = "gc_min_interval", 2854 .data = &ip_rt_gc_min_interval, 2855 .maxlen = sizeof(int), 2856 .mode = 0644, 2857 .proc_handler = proc_dointvec_jiffies, 2858 }, 2859 { 2860 .procname = "gc_min_interval_ms", 2861 .data = &ip_rt_gc_min_interval, 2862 .maxlen = sizeof(int), 2863 .mode = 0644, 2864 .proc_handler = proc_dointvec_ms_jiffies, 2865 }, 2866 { 2867 .procname = "gc_timeout", 2868 .data = &ip_rt_gc_timeout, 2869 .maxlen = sizeof(int), 2870 .mode = 0644, 2871 .proc_handler = proc_dointvec_jiffies, 2872 }, 2873 { 2874 .procname = "gc_interval", 2875 .data = &ip_rt_gc_interval, 2876 .maxlen = sizeof(int), 2877 .mode = 0644, 2878 .proc_handler = proc_dointvec_jiffies, 2879 }, 2880 { 2881 .procname = "redirect_load", 2882 .data = &ip_rt_redirect_load, 2883 .maxlen = sizeof(int), 2884 .mode = 0644, 2885 .proc_handler = proc_dointvec, 2886 }, 2887 { 2888 .procname = "redirect_number", 2889 .data = &ip_rt_redirect_number, 2890 .maxlen = sizeof(int), 2891 .mode = 0644, 2892 .proc_handler = proc_dointvec, 2893 }, 2894 { 2895 .procname = "redirect_silence", 2896 .data = &ip_rt_redirect_silence, 2897 .maxlen = sizeof(int), 2898 .mode = 0644, 2899 .proc_handler = proc_dointvec, 2900 }, 2901 { 2902 .procname = "error_cost", 2903 .data = &ip_rt_error_cost, 2904 .maxlen = sizeof(int), 2905 .mode = 0644, 2906 .proc_handler = proc_dointvec, 2907 }, 2908 { 2909 .procname = "error_burst", 2910 .data = &ip_rt_error_burst, 2911 .maxlen = sizeof(int), 2912 .mode = 0644, 2913 .proc_handler = proc_dointvec, 2914 }, 2915 { 2916 .procname = "gc_elasticity", 2917 .data = &ip_rt_gc_elasticity, 2918 .maxlen = sizeof(int), 2919 .mode = 0644, 2920 .proc_handler = proc_dointvec, 2921 }, 2922 { 2923 .procname = "mtu_expires", 2924 .data = &ip_rt_mtu_expires, 2925 .maxlen = sizeof(int), 2926 .mode = 0644, 2927 .proc_handler = proc_dointvec_jiffies, 2928 }, 2929 { 2930 .procname = "min_pmtu", 2931 .data = &ip_rt_min_pmtu, 2932 .maxlen = sizeof(int), 2933 .mode = 0644, 2934 .proc_handler = proc_dointvec, 2935 }, 2936 { 2937 .procname = "min_adv_mss", 2938 .data = &ip_rt_min_advmss, 2939 .maxlen = sizeof(int), 2940 .mode = 0644, 2941 .proc_handler = proc_dointvec, 2942 }, 2943 { } 2944 }; 2945 2946 static struct ctl_table ipv4_route_flush_table[] = { 2947 { 2948 .procname = "flush", 2949 .maxlen = sizeof(int), 2950 .mode = 0200, 2951 .proc_handler = ipv4_sysctl_rtcache_flush, 2952 }, 2953 { }, 2954 }; 2955 2956 static __net_init int sysctl_route_net_init(struct net *net) 2957 { 2958 struct ctl_table *tbl; 2959 2960 tbl = ipv4_route_flush_table; 2961 if (!net_eq(net, &init_net)) { 2962 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2963 if (!tbl) 2964 goto err_dup; 2965 2966 /* Don't export sysctls to unprivileged users */ 2967 if (net->user_ns != &init_user_ns) 2968 tbl[0].procname = NULL; 2969 } 2970 tbl[0].extra1 = net; 2971 2972 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2973 if (!net->ipv4.route_hdr) 2974 goto err_reg; 2975 return 0; 2976 2977 err_reg: 2978 if (tbl != ipv4_route_flush_table) 2979 kfree(tbl); 2980 err_dup: 2981 return -ENOMEM; 2982 } 2983 2984 static __net_exit void sysctl_route_net_exit(struct net *net) 2985 { 2986 struct ctl_table *tbl; 2987 2988 tbl = net->ipv4.route_hdr->ctl_table_arg; 2989 unregister_net_sysctl_table(net->ipv4.route_hdr); 2990 BUG_ON(tbl == ipv4_route_flush_table); 2991 kfree(tbl); 2992 } 2993 2994 static __net_initdata struct pernet_operations sysctl_route_ops = { 2995 .init = sysctl_route_net_init, 2996 .exit = sysctl_route_net_exit, 2997 }; 2998 #endif 2999 3000 static __net_init int rt_genid_init(struct net *net) 3001 { 3002 atomic_set(&net->ipv4.rt_genid, 0); 3003 atomic_set(&net->fnhe_genid, 0); 3004 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3005 return 0; 3006 } 3007 3008 static __net_initdata struct pernet_operations rt_genid_ops = { 3009 .init = rt_genid_init, 3010 }; 3011 3012 static int __net_init ipv4_inetpeer_init(struct net *net) 3013 { 3014 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3015 3016 if (!bp) 3017 return -ENOMEM; 3018 inet_peer_base_init(bp); 3019 net->ipv4.peers = bp; 3020 return 0; 3021 } 3022 3023 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3024 { 3025 struct inet_peer_base *bp = net->ipv4.peers; 3026 3027 net->ipv4.peers = NULL; 3028 inetpeer_invalidate_tree(bp); 3029 kfree(bp); 3030 } 3031 3032 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3033 .init = ipv4_inetpeer_init, 3034 .exit = ipv4_inetpeer_exit, 3035 }; 3036 3037 #ifdef CONFIG_IP_ROUTE_CLASSID 3038 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3039 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3040 3041 int __init ip_rt_init(void) 3042 { 3043 int cpu; 3044 3045 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 3046 if (!ip_idents) 3047 panic("IP: failed to allocate ip_idents\n"); 3048 3049 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3050 3051 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3052 if (!ip_tstamps) 3053 panic("IP: failed to allocate ip_tstamps\n"); 3054 3055 for_each_possible_cpu(cpu) { 3056 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3057 3058 INIT_LIST_HEAD(&ul->head); 3059 spin_lock_init(&ul->lock); 3060 } 3061 #ifdef CONFIG_IP_ROUTE_CLASSID 3062 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3063 if (!ip_rt_acct) 3064 panic("IP: failed to allocate ip_rt_acct\n"); 3065 #endif 3066 3067 ipv4_dst_ops.kmem_cachep = 3068 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3069 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3070 3071 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3072 3073 if (dst_entries_init(&ipv4_dst_ops) < 0) 3074 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3075 3076 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3077 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3078 3079 ipv4_dst_ops.gc_thresh = ~0; 3080 ip_rt_max_size = INT_MAX; 3081 3082 devinet_init(); 3083 ip_fib_init(); 3084 3085 if (ip_rt_proc_init()) 3086 pr_err("Unable to create route proc files\n"); 3087 #ifdef CONFIG_XFRM 3088 xfrm_init(); 3089 xfrm4_init(); 3090 #endif 3091 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3092 RTNL_FLAG_DOIT_UNLOCKED); 3093 3094 #ifdef CONFIG_SYSCTL 3095 register_pernet_subsys(&sysctl_route_ops); 3096 #endif 3097 register_pernet_subsys(&rt_genid_ops); 3098 register_pernet_subsys(&ipv4_inetpeer_ops); 3099 return 0; 3100 } 3101 3102 #ifdef CONFIG_SYSCTL 3103 /* 3104 * We really need to sanitize the damn ipv4 init order, then all 3105 * this nonsense will go away. 3106 */ 3107 void __init ip_static_sysctl_init(void) 3108 { 3109 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3110 } 3111 #endif 3112