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