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 #endif 112 #include <net/secure_seq.h> 113 #include <net/ip_tunnels.h> 114 #include <net/l3mdev.h> 115 116 #include "fib_lookup.h" 117 118 #define RT_FL_TOS(oldflp4) \ 119 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 120 121 #define RT_GC_TIMEOUT (300*HZ) 122 123 static int ip_rt_max_size; 124 static int ip_rt_redirect_number __read_mostly = 9; 125 static int ip_rt_redirect_load __read_mostly = HZ / 50; 126 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 127 static int ip_rt_error_cost __read_mostly = HZ; 128 static int ip_rt_error_burst __read_mostly = 5 * HZ; 129 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 130 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 131 static int ip_rt_min_advmss __read_mostly = 256; 132 133 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 134 135 /* 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", 0444, net->proc_net, 382 &rt_cache_seq_fops); 383 if (!pde) 384 goto err1; 385 386 pde = proc_create("rt_cache", 0444, 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->rt_mtu_locked = fnhe->fnhe_mtu_locked; 637 rt->dst.expires = fnhe->fnhe_expires; 638 639 if (fnhe->fnhe_gw) { 640 rt->rt_flags |= RTCF_REDIRECTED; 641 rt->rt_gateway = fnhe->fnhe_gw; 642 rt->rt_uses_gateway = 1; 643 } 644 } 645 646 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 647 u32 pmtu, bool lock, unsigned long expires) 648 { 649 struct fnhe_hash_bucket *hash; 650 struct fib_nh_exception *fnhe; 651 struct rtable *rt; 652 u32 genid, hval; 653 unsigned int i; 654 int depth; 655 656 genid = fnhe_genid(dev_net(nh->nh_dev)); 657 hval = fnhe_hashfun(daddr); 658 659 spin_lock_bh(&fnhe_lock); 660 661 hash = rcu_dereference(nh->nh_exceptions); 662 if (!hash) { 663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 664 if (!hash) 665 goto out_unlock; 666 rcu_assign_pointer(nh->nh_exceptions, hash); 667 } 668 669 hash += hval; 670 671 depth = 0; 672 for (fnhe = rcu_dereference(hash->chain); fnhe; 673 fnhe = rcu_dereference(fnhe->fnhe_next)) { 674 if (fnhe->fnhe_daddr == daddr) 675 break; 676 depth++; 677 } 678 679 if (fnhe) { 680 if (fnhe->fnhe_genid != genid) 681 fnhe->fnhe_genid = genid; 682 if (gw) 683 fnhe->fnhe_gw = gw; 684 if (pmtu) { 685 fnhe->fnhe_pmtu = pmtu; 686 fnhe->fnhe_mtu_locked = lock; 687 } 688 fnhe->fnhe_expires = max(1UL, expires); 689 /* Update all cached dsts too */ 690 rt = rcu_dereference(fnhe->fnhe_rth_input); 691 if (rt) 692 fill_route_from_fnhe(rt, fnhe); 693 rt = rcu_dereference(fnhe->fnhe_rth_output); 694 if (rt) 695 fill_route_from_fnhe(rt, fnhe); 696 } else { 697 if (depth > FNHE_RECLAIM_DEPTH) 698 fnhe = fnhe_oldest(hash); 699 else { 700 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 701 if (!fnhe) 702 goto out_unlock; 703 704 fnhe->fnhe_next = hash->chain; 705 rcu_assign_pointer(hash->chain, fnhe); 706 } 707 fnhe->fnhe_genid = genid; 708 fnhe->fnhe_daddr = daddr; 709 fnhe->fnhe_gw = gw; 710 fnhe->fnhe_pmtu = pmtu; 711 fnhe->fnhe_mtu_locked = lock; 712 fnhe->fnhe_expires = expires; 713 714 /* Exception created; mark the cached routes for the nexthop 715 * stale, so anyone caching it rechecks if this exception 716 * applies to them. 717 */ 718 rt = rcu_dereference(nh->nh_rth_input); 719 if (rt) 720 rt->dst.obsolete = DST_OBSOLETE_KILL; 721 722 for_each_possible_cpu(i) { 723 struct rtable __rcu **prt; 724 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 725 rt = rcu_dereference(*prt); 726 if (rt) 727 rt->dst.obsolete = DST_OBSOLETE_KILL; 728 } 729 } 730 731 fnhe->fnhe_stamp = jiffies; 732 733 out_unlock: 734 spin_unlock_bh(&fnhe_lock); 735 } 736 737 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 738 bool kill_route) 739 { 740 __be32 new_gw = icmp_hdr(skb)->un.gateway; 741 __be32 old_gw = ip_hdr(skb)->saddr; 742 struct net_device *dev = skb->dev; 743 struct in_device *in_dev; 744 struct fib_result res; 745 struct neighbour *n; 746 struct net *net; 747 748 switch (icmp_hdr(skb)->code & 7) { 749 case ICMP_REDIR_NET: 750 case ICMP_REDIR_NETTOS: 751 case ICMP_REDIR_HOST: 752 case ICMP_REDIR_HOSTTOS: 753 break; 754 755 default: 756 return; 757 } 758 759 if (rt->rt_gateway != old_gw) 760 return; 761 762 in_dev = __in_dev_get_rcu(dev); 763 if (!in_dev) 764 return; 765 766 net = dev_net(dev); 767 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 768 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 769 ipv4_is_zeronet(new_gw)) 770 goto reject_redirect; 771 772 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 773 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 774 goto reject_redirect; 775 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 776 goto reject_redirect; 777 } else { 778 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 779 goto reject_redirect; 780 } 781 782 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 783 if (!n) 784 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 785 if (!IS_ERR(n)) { 786 if (!(n->nud_state & NUD_VALID)) { 787 neigh_event_send(n, NULL); 788 } else { 789 if (fib_lookup(net, fl4, &res, 0) == 0) { 790 struct fib_nh *nh = &FIB_RES_NH(res); 791 792 update_or_create_fnhe(nh, fl4->daddr, new_gw, 793 0, false, 794 jiffies + ip_rt_gc_timeout); 795 } 796 if (kill_route) 797 rt->dst.obsolete = DST_OBSOLETE_KILL; 798 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 799 } 800 neigh_release(n); 801 } 802 return; 803 804 reject_redirect: 805 #ifdef CONFIG_IP_ROUTE_VERBOSE 806 if (IN_DEV_LOG_MARTIANS(in_dev)) { 807 const struct iphdr *iph = (const struct iphdr *) skb->data; 808 __be32 daddr = iph->daddr; 809 __be32 saddr = iph->saddr; 810 811 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 812 " Advised path = %pI4 -> %pI4\n", 813 &old_gw, dev->name, &new_gw, 814 &saddr, &daddr); 815 } 816 #endif 817 ; 818 } 819 820 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 821 { 822 struct rtable *rt; 823 struct flowi4 fl4; 824 const struct iphdr *iph = (const struct iphdr *) skb->data; 825 struct net *net = dev_net(skb->dev); 826 int oif = skb->dev->ifindex; 827 u8 tos = RT_TOS(iph->tos); 828 u8 prot = iph->protocol; 829 u32 mark = skb->mark; 830 831 rt = (struct rtable *) dst; 832 833 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 834 __ip_do_redirect(rt, skb, &fl4, true); 835 } 836 837 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 838 { 839 struct rtable *rt = (struct rtable *)dst; 840 struct dst_entry *ret = dst; 841 842 if (rt) { 843 if (dst->obsolete > 0) { 844 ip_rt_put(rt); 845 ret = NULL; 846 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 847 rt->dst.expires) { 848 ip_rt_put(rt); 849 ret = NULL; 850 } 851 } 852 return ret; 853 } 854 855 /* 856 * Algorithm: 857 * 1. The first ip_rt_redirect_number redirects are sent 858 * with exponential backoff, then we stop sending them at all, 859 * assuming that the host ignores our redirects. 860 * 2. If we did not see packets requiring redirects 861 * during ip_rt_redirect_silence, we assume that the host 862 * forgot redirected route and start to send redirects again. 863 * 864 * This algorithm is much cheaper and more intelligent than dumb load limiting 865 * in icmp.c. 866 * 867 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 868 * and "frag. need" (breaks PMTU discovery) in icmp.c. 869 */ 870 871 void ip_rt_send_redirect(struct sk_buff *skb) 872 { 873 struct rtable *rt = skb_rtable(skb); 874 struct in_device *in_dev; 875 struct inet_peer *peer; 876 struct net *net; 877 int log_martians; 878 int vif; 879 880 rcu_read_lock(); 881 in_dev = __in_dev_get_rcu(rt->dst.dev); 882 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 883 rcu_read_unlock(); 884 return; 885 } 886 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 887 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 888 rcu_read_unlock(); 889 890 net = dev_net(rt->dst.dev); 891 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 892 if (!peer) { 893 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 894 rt_nexthop(rt, ip_hdr(skb)->daddr)); 895 return; 896 } 897 898 /* No redirected packets during ip_rt_redirect_silence; 899 * reset the algorithm. 900 */ 901 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 902 peer->rate_tokens = 0; 903 904 /* Too many ignored redirects; do not send anything 905 * set dst.rate_last to the last seen redirected packet. 906 */ 907 if (peer->rate_tokens >= ip_rt_redirect_number) { 908 peer->rate_last = jiffies; 909 goto out_put_peer; 910 } 911 912 /* Check for load limit; set rate_last to the latest sent 913 * redirect. 914 */ 915 if (peer->rate_tokens == 0 || 916 time_after(jiffies, 917 (peer->rate_last + 918 (ip_rt_redirect_load << peer->rate_tokens)))) { 919 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 920 921 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 922 peer->rate_last = jiffies; 923 ++peer->rate_tokens; 924 #ifdef CONFIG_IP_ROUTE_VERBOSE 925 if (log_martians && 926 peer->rate_tokens == ip_rt_redirect_number) 927 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 928 &ip_hdr(skb)->saddr, inet_iif(skb), 929 &ip_hdr(skb)->daddr, &gw); 930 #endif 931 } 932 out_put_peer: 933 inet_putpeer(peer); 934 } 935 936 static int ip_error(struct sk_buff *skb) 937 { 938 struct rtable *rt = skb_rtable(skb); 939 struct net_device *dev = skb->dev; 940 struct in_device *in_dev; 941 struct inet_peer *peer; 942 unsigned long now; 943 struct net *net; 944 bool send; 945 int code; 946 947 if (netif_is_l3_master(skb->dev)) { 948 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 949 if (!dev) 950 goto out; 951 } 952 953 in_dev = __in_dev_get_rcu(dev); 954 955 /* IP on this device is disabled. */ 956 if (!in_dev) 957 goto out; 958 959 net = dev_net(rt->dst.dev); 960 if (!IN_DEV_FORWARD(in_dev)) { 961 switch (rt->dst.error) { 962 case EHOSTUNREACH: 963 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 964 break; 965 966 case ENETUNREACH: 967 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 968 break; 969 } 970 goto out; 971 } 972 973 switch (rt->dst.error) { 974 case EINVAL: 975 default: 976 goto out; 977 case EHOSTUNREACH: 978 code = ICMP_HOST_UNREACH; 979 break; 980 case ENETUNREACH: 981 code = ICMP_NET_UNREACH; 982 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 983 break; 984 case EACCES: 985 code = ICMP_PKT_FILTERED; 986 break; 987 } 988 989 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 990 l3mdev_master_ifindex(skb->dev), 1); 991 992 send = true; 993 if (peer) { 994 now = jiffies; 995 peer->rate_tokens += now - peer->rate_last; 996 if (peer->rate_tokens > ip_rt_error_burst) 997 peer->rate_tokens = ip_rt_error_burst; 998 peer->rate_last = now; 999 if (peer->rate_tokens >= ip_rt_error_cost) 1000 peer->rate_tokens -= ip_rt_error_cost; 1001 else 1002 send = false; 1003 inet_putpeer(peer); 1004 } 1005 if (send) 1006 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1007 1008 out: kfree_skb(skb); 1009 return 0; 1010 } 1011 1012 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1013 { 1014 struct dst_entry *dst = &rt->dst; 1015 struct fib_result res; 1016 bool lock = false; 1017 1018 if (ip_mtu_locked(dst)) 1019 return; 1020 1021 if (ipv4_mtu(dst) < mtu) 1022 return; 1023 1024 if (mtu < ip_rt_min_pmtu) { 1025 lock = true; 1026 mtu = ip_rt_min_pmtu; 1027 } 1028 1029 if (rt->rt_pmtu == mtu && 1030 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1031 return; 1032 1033 rcu_read_lock(); 1034 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1035 struct fib_nh *nh = &FIB_RES_NH(res); 1036 1037 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock, 1038 jiffies + ip_rt_mtu_expires); 1039 } 1040 rcu_read_unlock(); 1041 } 1042 1043 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1044 struct sk_buff *skb, u32 mtu) 1045 { 1046 struct rtable *rt = (struct rtable *) dst; 1047 struct flowi4 fl4; 1048 1049 ip_rt_build_flow_key(&fl4, sk, skb); 1050 __ip_rt_update_pmtu(rt, &fl4, mtu); 1051 } 1052 1053 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1054 int oif, u32 mark, u8 protocol, int flow_flags) 1055 { 1056 const struct iphdr *iph = (const struct iphdr *) skb->data; 1057 struct flowi4 fl4; 1058 struct rtable *rt; 1059 1060 if (!mark) 1061 mark = IP4_REPLY_MARK(net, skb->mark); 1062 1063 __build_flow_key(net, &fl4, NULL, iph, oif, 1064 RT_TOS(iph->tos), protocol, mark, flow_flags); 1065 rt = __ip_route_output_key(net, &fl4); 1066 if (!IS_ERR(rt)) { 1067 __ip_rt_update_pmtu(rt, &fl4, mtu); 1068 ip_rt_put(rt); 1069 } 1070 } 1071 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1072 1073 static 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 1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1080 1081 if (!fl4.flowi4_mark) 1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1083 1084 rt = __ip_route_output_key(sock_net(sk), &fl4); 1085 if (!IS_ERR(rt)) { 1086 __ip_rt_update_pmtu(rt, &fl4, mtu); 1087 ip_rt_put(rt); 1088 } 1089 } 1090 1091 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1092 { 1093 const struct iphdr *iph = (const struct iphdr *) skb->data; 1094 struct flowi4 fl4; 1095 struct rtable *rt; 1096 struct dst_entry *odst = NULL; 1097 bool new = false; 1098 struct net *net = sock_net(sk); 1099 1100 bh_lock_sock(sk); 1101 1102 if (!ip_sk_accept_pmtu(sk)) 1103 goto out; 1104 1105 odst = sk_dst_get(sk); 1106 1107 if (sock_owned_by_user(sk) || !odst) { 1108 __ipv4_sk_update_pmtu(skb, sk, mtu); 1109 goto out; 1110 } 1111 1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1113 1114 rt = (struct rtable *)odst; 1115 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1117 if (IS_ERR(rt)) 1118 goto out; 1119 1120 new = true; 1121 } 1122 1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1124 1125 if (!dst_check(&rt->dst, 0)) { 1126 if (new) 1127 dst_release(&rt->dst); 1128 1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1130 if (IS_ERR(rt)) 1131 goto out; 1132 1133 new = true; 1134 } 1135 1136 if (new) 1137 sk_dst_set(sk, &rt->dst); 1138 1139 out: 1140 bh_unlock_sock(sk); 1141 dst_release(odst); 1142 } 1143 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1144 1145 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1146 int oif, u32 mark, u8 protocol, int flow_flags) 1147 { 1148 const struct iphdr *iph = (const struct iphdr *) skb->data; 1149 struct flowi4 fl4; 1150 struct rtable *rt; 1151 1152 __build_flow_key(net, &fl4, NULL, iph, oif, 1153 RT_TOS(iph->tos), protocol, mark, flow_flags); 1154 rt = __ip_route_output_key(net, &fl4); 1155 if (!IS_ERR(rt)) { 1156 __ip_do_redirect(rt, skb, &fl4, false); 1157 ip_rt_put(rt); 1158 } 1159 } 1160 EXPORT_SYMBOL_GPL(ipv4_redirect); 1161 1162 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1163 { 1164 const struct iphdr *iph = (const struct iphdr *) skb->data; 1165 struct flowi4 fl4; 1166 struct rtable *rt; 1167 struct net *net = sock_net(sk); 1168 1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1170 rt = __ip_route_output_key(net, &fl4); 1171 if (!IS_ERR(rt)) { 1172 __ip_do_redirect(rt, skb, &fl4, false); 1173 ip_rt_put(rt); 1174 } 1175 } 1176 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1177 1178 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1179 { 1180 struct rtable *rt = (struct rtable *) dst; 1181 1182 /* All IPV4 dsts are created with ->obsolete set to the value 1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1184 * into this function always. 1185 * 1186 * When a PMTU/redirect information update invalidates a route, 1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1188 * DST_OBSOLETE_DEAD by dst_free(). 1189 */ 1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1191 return NULL; 1192 return dst; 1193 } 1194 1195 static void ipv4_link_failure(struct sk_buff *skb) 1196 { 1197 struct rtable *rt; 1198 1199 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1200 1201 rt = skb_rtable(skb); 1202 if (rt) 1203 dst_set_expires(&rt->dst, 0); 1204 } 1205 1206 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1207 { 1208 pr_debug("%s: %pI4 -> %pI4, %s\n", 1209 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1210 skb->dev ? skb->dev->name : "?"); 1211 kfree_skb(skb); 1212 WARN_ON(1); 1213 return 0; 1214 } 1215 1216 /* 1217 We do not cache source address of outgoing interface, 1218 because it is used only by IP RR, TS and SRR options, 1219 so that it out of fast path. 1220 1221 BTW remember: "addr" is allowed to be not aligned 1222 in IP options! 1223 */ 1224 1225 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1226 { 1227 __be32 src; 1228 1229 if (rt_is_output_route(rt)) 1230 src = ip_hdr(skb)->saddr; 1231 else { 1232 struct fib_result res; 1233 struct flowi4 fl4; 1234 struct iphdr *iph; 1235 1236 iph = ip_hdr(skb); 1237 1238 memset(&fl4, 0, sizeof(fl4)); 1239 fl4.daddr = iph->daddr; 1240 fl4.saddr = iph->saddr; 1241 fl4.flowi4_tos = RT_TOS(iph->tos); 1242 fl4.flowi4_oif = rt->dst.dev->ifindex; 1243 fl4.flowi4_iif = skb->dev->ifindex; 1244 fl4.flowi4_mark = skb->mark; 1245 1246 rcu_read_lock(); 1247 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1248 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1249 else 1250 src = inet_select_addr(rt->dst.dev, 1251 rt_nexthop(rt, iph->daddr), 1252 RT_SCOPE_UNIVERSE); 1253 rcu_read_unlock(); 1254 } 1255 memcpy(addr, &src, 4); 1256 } 1257 1258 #ifdef CONFIG_IP_ROUTE_CLASSID 1259 static void set_class_tag(struct rtable *rt, u32 tag) 1260 { 1261 if (!(rt->dst.tclassid & 0xFFFF)) 1262 rt->dst.tclassid |= tag & 0xFFFF; 1263 if (!(rt->dst.tclassid & 0xFFFF0000)) 1264 rt->dst.tclassid |= tag & 0xFFFF0000; 1265 } 1266 #endif 1267 1268 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1269 { 1270 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1271 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1272 ip_rt_min_advmss); 1273 1274 return min(advmss, IPV4_MAX_PMTU - header_size); 1275 } 1276 1277 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1278 { 1279 const struct rtable *rt = (const struct rtable *) dst; 1280 unsigned int mtu = rt->rt_pmtu; 1281 1282 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1283 mtu = dst_metric_raw(dst, RTAX_MTU); 1284 1285 if (mtu) 1286 return mtu; 1287 1288 mtu = READ_ONCE(dst->dev->mtu); 1289 1290 if (unlikely(ip_mtu_locked(dst))) { 1291 if (rt->rt_uses_gateway && mtu > 576) 1292 mtu = 576; 1293 } 1294 1295 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1296 1297 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1298 } 1299 1300 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1301 { 1302 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1303 struct fib_nh_exception *fnhe; 1304 u32 hval; 1305 1306 if (!hash) 1307 return NULL; 1308 1309 hval = fnhe_hashfun(daddr); 1310 1311 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1312 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1313 if (fnhe->fnhe_daddr == daddr) 1314 return fnhe; 1315 } 1316 return NULL; 1317 } 1318 1319 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1320 __be32 daddr, const bool do_cache) 1321 { 1322 bool ret = false; 1323 1324 spin_lock_bh(&fnhe_lock); 1325 1326 if (daddr == fnhe->fnhe_daddr) { 1327 struct rtable __rcu **porig; 1328 struct rtable *orig; 1329 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1330 1331 if (rt_is_input_route(rt)) 1332 porig = &fnhe->fnhe_rth_input; 1333 else 1334 porig = &fnhe->fnhe_rth_output; 1335 orig = rcu_dereference(*porig); 1336 1337 if (fnhe->fnhe_genid != genid) { 1338 fnhe->fnhe_genid = genid; 1339 fnhe->fnhe_gw = 0; 1340 fnhe->fnhe_pmtu = 0; 1341 fnhe->fnhe_expires = 0; 1342 fnhe_flush_routes(fnhe); 1343 orig = NULL; 1344 } 1345 fill_route_from_fnhe(rt, fnhe); 1346 if (!rt->rt_gateway) 1347 rt->rt_gateway = daddr; 1348 1349 if (do_cache) { 1350 dst_hold(&rt->dst); 1351 rcu_assign_pointer(*porig, rt); 1352 if (orig) { 1353 dst_dev_put(&orig->dst); 1354 dst_release(&orig->dst); 1355 } 1356 ret = true; 1357 } 1358 1359 fnhe->fnhe_stamp = jiffies; 1360 } 1361 spin_unlock_bh(&fnhe_lock); 1362 1363 return ret; 1364 } 1365 1366 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1367 { 1368 struct rtable *orig, *prev, **p; 1369 bool ret = true; 1370 1371 if (rt_is_input_route(rt)) { 1372 p = (struct rtable **)&nh->nh_rth_input; 1373 } else { 1374 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1375 } 1376 orig = *p; 1377 1378 /* hold dst before doing cmpxchg() to avoid race condition 1379 * on this dst 1380 */ 1381 dst_hold(&rt->dst); 1382 prev = cmpxchg(p, orig, rt); 1383 if (prev == orig) { 1384 if (orig) { 1385 dst_dev_put(&orig->dst); 1386 dst_release(&orig->dst); 1387 } 1388 } else { 1389 dst_release(&rt->dst); 1390 ret = false; 1391 } 1392 1393 return ret; 1394 } 1395 1396 struct uncached_list { 1397 spinlock_t lock; 1398 struct list_head head; 1399 }; 1400 1401 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1402 1403 void rt_add_uncached_list(struct rtable *rt) 1404 { 1405 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1406 1407 rt->rt_uncached_list = ul; 1408 1409 spin_lock_bh(&ul->lock); 1410 list_add_tail(&rt->rt_uncached, &ul->head); 1411 spin_unlock_bh(&ul->lock); 1412 } 1413 1414 void rt_del_uncached_list(struct rtable *rt) 1415 { 1416 if (!list_empty(&rt->rt_uncached)) { 1417 struct uncached_list *ul = rt->rt_uncached_list; 1418 1419 spin_lock_bh(&ul->lock); 1420 list_del(&rt->rt_uncached); 1421 spin_unlock_bh(&ul->lock); 1422 } 1423 } 1424 1425 static void ipv4_dst_destroy(struct dst_entry *dst) 1426 { 1427 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst); 1428 struct rtable *rt = (struct rtable *)dst; 1429 1430 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt)) 1431 kfree(p); 1432 1433 rt_del_uncached_list(rt); 1434 } 1435 1436 void rt_flush_dev(struct net_device *dev) 1437 { 1438 struct net *net = dev_net(dev); 1439 struct rtable *rt; 1440 int cpu; 1441 1442 for_each_possible_cpu(cpu) { 1443 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1444 1445 spin_lock_bh(&ul->lock); 1446 list_for_each_entry(rt, &ul->head, rt_uncached) { 1447 if (rt->dst.dev != dev) 1448 continue; 1449 rt->dst.dev = net->loopback_dev; 1450 dev_hold(rt->dst.dev); 1451 dev_put(dev); 1452 } 1453 spin_unlock_bh(&ul->lock); 1454 } 1455 } 1456 1457 static bool rt_cache_valid(const struct rtable *rt) 1458 { 1459 return rt && 1460 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1461 !rt_is_expired(rt); 1462 } 1463 1464 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1465 const struct fib_result *res, 1466 struct fib_nh_exception *fnhe, 1467 struct fib_info *fi, u16 type, u32 itag, 1468 const bool do_cache) 1469 { 1470 bool cached = false; 1471 1472 if (fi) { 1473 struct fib_nh *nh = &FIB_RES_NH(*res); 1474 1475 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1476 rt->rt_gateway = nh->nh_gw; 1477 rt->rt_uses_gateway = 1; 1478 } 1479 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true); 1480 if (fi->fib_metrics != &dst_default_metrics) { 1481 rt->dst._metrics |= DST_METRICS_REFCOUNTED; 1482 refcount_inc(&fi->fib_metrics->refcnt); 1483 } 1484 #ifdef CONFIG_IP_ROUTE_CLASSID 1485 rt->dst.tclassid = nh->nh_tclassid; 1486 #endif 1487 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1488 if (unlikely(fnhe)) 1489 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1490 else if (do_cache) 1491 cached = rt_cache_route(nh, rt); 1492 if (unlikely(!cached)) { 1493 /* Routes we intend to cache in nexthop exception or 1494 * FIB nexthop have the DST_NOCACHE bit clear. 1495 * However, if we are unsuccessful at storing this 1496 * route into the cache we really need to set it. 1497 */ 1498 if (!rt->rt_gateway) 1499 rt->rt_gateway = daddr; 1500 rt_add_uncached_list(rt); 1501 } 1502 } else 1503 rt_add_uncached_list(rt); 1504 1505 #ifdef CONFIG_IP_ROUTE_CLASSID 1506 #ifdef CONFIG_IP_MULTIPLE_TABLES 1507 set_class_tag(rt, res->tclassid); 1508 #endif 1509 set_class_tag(rt, itag); 1510 #endif 1511 } 1512 1513 struct rtable *rt_dst_alloc(struct net_device *dev, 1514 unsigned int flags, u16 type, 1515 bool nopolicy, bool noxfrm, bool will_cache) 1516 { 1517 struct rtable *rt; 1518 1519 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1520 (will_cache ? 0 : DST_HOST) | 1521 (nopolicy ? DST_NOPOLICY : 0) | 1522 (noxfrm ? DST_NOXFRM : 0)); 1523 1524 if (rt) { 1525 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1526 rt->rt_flags = flags; 1527 rt->rt_type = type; 1528 rt->rt_is_input = 0; 1529 rt->rt_iif = 0; 1530 rt->rt_pmtu = 0; 1531 rt->rt_mtu_locked = 0; 1532 rt->rt_gateway = 0; 1533 rt->rt_uses_gateway = 0; 1534 INIT_LIST_HEAD(&rt->rt_uncached); 1535 1536 rt->dst.output = ip_output; 1537 if (flags & RTCF_LOCAL) 1538 rt->dst.input = ip_local_deliver; 1539 } 1540 1541 return rt; 1542 } 1543 EXPORT_SYMBOL(rt_dst_alloc); 1544 1545 /* called in rcu_read_lock() section */ 1546 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1547 u8 tos, struct net_device *dev, 1548 struct in_device *in_dev, u32 *itag) 1549 { 1550 int err; 1551 1552 /* Primary sanity checks. */ 1553 if (!in_dev) 1554 return -EINVAL; 1555 1556 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1557 skb->protocol != htons(ETH_P_IP)) 1558 return -EINVAL; 1559 1560 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1561 return -EINVAL; 1562 1563 if (ipv4_is_zeronet(saddr)) { 1564 if (!ipv4_is_local_multicast(daddr)) 1565 return -EINVAL; 1566 } else { 1567 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1568 in_dev, itag); 1569 if (err < 0) 1570 return err; 1571 } 1572 return 0; 1573 } 1574 1575 /* called in rcu_read_lock() section */ 1576 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1577 u8 tos, struct net_device *dev, int our) 1578 { 1579 struct in_device *in_dev = __in_dev_get_rcu(dev); 1580 unsigned int flags = RTCF_MULTICAST; 1581 struct rtable *rth; 1582 u32 itag = 0; 1583 int err; 1584 1585 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1586 if (err) 1587 return err; 1588 1589 if (our) 1590 flags |= RTCF_LOCAL; 1591 1592 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1593 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1594 if (!rth) 1595 return -ENOBUFS; 1596 1597 #ifdef CONFIG_IP_ROUTE_CLASSID 1598 rth->dst.tclassid = itag; 1599 #endif 1600 rth->dst.output = ip_rt_bug; 1601 rth->rt_is_input= 1; 1602 1603 #ifdef CONFIG_IP_MROUTE 1604 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1605 rth->dst.input = ip_mr_input; 1606 #endif 1607 RT_CACHE_STAT_INC(in_slow_mc); 1608 1609 skb_dst_set(skb, &rth->dst); 1610 return 0; 1611 } 1612 1613 1614 static void ip_handle_martian_source(struct net_device *dev, 1615 struct in_device *in_dev, 1616 struct sk_buff *skb, 1617 __be32 daddr, 1618 __be32 saddr) 1619 { 1620 RT_CACHE_STAT_INC(in_martian_src); 1621 #ifdef CONFIG_IP_ROUTE_VERBOSE 1622 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1623 /* 1624 * RFC1812 recommendation, if source is martian, 1625 * the only hint is MAC header. 1626 */ 1627 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1628 &daddr, &saddr, dev->name); 1629 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1630 print_hex_dump(KERN_WARNING, "ll header: ", 1631 DUMP_PREFIX_OFFSET, 16, 1, 1632 skb_mac_header(skb), 1633 dev->hard_header_len, true); 1634 } 1635 } 1636 #endif 1637 } 1638 1639 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1640 { 1641 struct fnhe_hash_bucket *hash; 1642 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1643 u32 hval = fnhe_hashfun(daddr); 1644 1645 spin_lock_bh(&fnhe_lock); 1646 1647 hash = rcu_dereference_protected(nh->nh_exceptions, 1648 lockdep_is_held(&fnhe_lock)); 1649 hash += hval; 1650 1651 fnhe_p = &hash->chain; 1652 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1653 while (fnhe) { 1654 if (fnhe->fnhe_daddr == daddr) { 1655 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1656 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1657 fnhe_flush_routes(fnhe); 1658 kfree_rcu(fnhe, rcu); 1659 break; 1660 } 1661 fnhe_p = &fnhe->fnhe_next; 1662 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1663 lockdep_is_held(&fnhe_lock)); 1664 } 1665 1666 spin_unlock_bh(&fnhe_lock); 1667 } 1668 1669 /* called in rcu_read_lock() section */ 1670 static int __mkroute_input(struct sk_buff *skb, 1671 const struct fib_result *res, 1672 struct in_device *in_dev, 1673 __be32 daddr, __be32 saddr, u32 tos) 1674 { 1675 struct fib_nh_exception *fnhe; 1676 struct rtable *rth; 1677 int err; 1678 struct in_device *out_dev; 1679 bool do_cache; 1680 u32 itag = 0; 1681 1682 /* get a working reference to the output device */ 1683 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1684 if (!out_dev) { 1685 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1686 return -EINVAL; 1687 } 1688 1689 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1690 in_dev->dev, in_dev, &itag); 1691 if (err < 0) { 1692 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1693 saddr); 1694 1695 goto cleanup; 1696 } 1697 1698 do_cache = res->fi && !itag; 1699 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1700 skb->protocol == htons(ETH_P_IP) && 1701 (IN_DEV_SHARED_MEDIA(out_dev) || 1702 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1703 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1704 1705 if (skb->protocol != htons(ETH_P_IP)) { 1706 /* Not IP (i.e. ARP). Do not create route, if it is 1707 * invalid for proxy arp. DNAT routes are always valid. 1708 * 1709 * Proxy arp feature have been extended to allow, ARP 1710 * replies back to the same interface, to support 1711 * Private VLAN switch technologies. See arp.c. 1712 */ 1713 if (out_dev == in_dev && 1714 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1715 err = -EINVAL; 1716 goto cleanup; 1717 } 1718 } 1719 1720 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1721 if (do_cache) { 1722 if (fnhe) { 1723 rth = rcu_dereference(fnhe->fnhe_rth_input); 1724 if (rth && rth->dst.expires && 1725 time_after(jiffies, rth->dst.expires)) { 1726 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1727 fnhe = NULL; 1728 } else { 1729 goto rt_cache; 1730 } 1731 } 1732 1733 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1734 1735 rt_cache: 1736 if (rt_cache_valid(rth)) { 1737 skb_dst_set_noref(skb, &rth->dst); 1738 goto out; 1739 } 1740 } 1741 1742 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1743 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1744 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1745 if (!rth) { 1746 err = -ENOBUFS; 1747 goto cleanup; 1748 } 1749 1750 rth->rt_is_input = 1; 1751 RT_CACHE_STAT_INC(in_slow_tot); 1752 1753 rth->dst.input = ip_forward; 1754 1755 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1756 do_cache); 1757 lwtunnel_set_redirect(&rth->dst); 1758 skb_dst_set(skb, &rth->dst); 1759 out: 1760 err = 0; 1761 cleanup: 1762 return err; 1763 } 1764 1765 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1766 /* To make ICMP packets follow the right flow, the multipath hash is 1767 * calculated from the inner IP addresses. 1768 */ 1769 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1770 struct flow_keys *hash_keys) 1771 { 1772 const struct iphdr *outer_iph = ip_hdr(skb); 1773 const struct iphdr *key_iph = outer_iph; 1774 const struct iphdr *inner_iph; 1775 const struct icmphdr *icmph; 1776 struct iphdr _inner_iph; 1777 struct icmphdr _icmph; 1778 1779 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1780 goto out; 1781 1782 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1783 goto out; 1784 1785 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1786 &_icmph); 1787 if (!icmph) 1788 goto out; 1789 1790 if (icmph->type != ICMP_DEST_UNREACH && 1791 icmph->type != ICMP_REDIRECT && 1792 icmph->type != ICMP_TIME_EXCEEDED && 1793 icmph->type != ICMP_PARAMETERPROB) 1794 goto out; 1795 1796 inner_iph = skb_header_pointer(skb, 1797 outer_iph->ihl * 4 + sizeof(_icmph), 1798 sizeof(_inner_iph), &_inner_iph); 1799 if (!inner_iph) 1800 goto out; 1801 1802 key_iph = inner_iph; 1803 out: 1804 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1805 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1806 } 1807 1808 /* if skb is set it will be used and fl4 can be NULL */ 1809 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1810 const struct sk_buff *skb, struct flow_keys *flkeys) 1811 { 1812 struct flow_keys hash_keys; 1813 u32 mhash; 1814 1815 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1816 case 0: 1817 memset(&hash_keys, 0, sizeof(hash_keys)); 1818 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1819 if (skb) { 1820 ip_multipath_l3_keys(skb, &hash_keys); 1821 } else { 1822 hash_keys.addrs.v4addrs.src = fl4->saddr; 1823 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1824 } 1825 break; 1826 case 1: 1827 /* skb is currently provided only when forwarding */ 1828 if (skb) { 1829 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1830 struct flow_keys keys; 1831 1832 /* short-circuit if we already have L4 hash present */ 1833 if (skb->l4_hash) 1834 return skb_get_hash_raw(skb) >> 1; 1835 1836 memset(&hash_keys, 0, sizeof(hash_keys)); 1837 1838 if (!flkeys) { 1839 skb_flow_dissect_flow_keys(skb, &keys, flag); 1840 flkeys = &keys; 1841 } 1842 1843 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1844 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1845 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1846 hash_keys.ports.src = flkeys->ports.src; 1847 hash_keys.ports.dst = flkeys->ports.dst; 1848 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1849 } else { 1850 memset(&hash_keys, 0, sizeof(hash_keys)); 1851 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1852 hash_keys.addrs.v4addrs.src = fl4->saddr; 1853 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1854 hash_keys.ports.src = fl4->fl4_sport; 1855 hash_keys.ports.dst = fl4->fl4_dport; 1856 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1857 } 1858 break; 1859 } 1860 mhash = flow_hash_from_keys(&hash_keys); 1861 1862 return mhash >> 1; 1863 } 1864 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1865 1866 static int ip_mkroute_input(struct sk_buff *skb, 1867 struct fib_result *res, 1868 struct in_device *in_dev, 1869 __be32 daddr, __be32 saddr, u32 tos, 1870 struct flow_keys *hkeys) 1871 { 1872 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1873 if (res->fi && res->fi->fib_nhs > 1) { 1874 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 1875 1876 fib_select_multipath(res, h); 1877 } 1878 #endif 1879 1880 /* create a routing cache entry */ 1881 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1882 } 1883 1884 /* 1885 * NOTE. We drop all the packets that has local source 1886 * addresses, because every properly looped back packet 1887 * must have correct destination already attached by output routine. 1888 * 1889 * Such approach solves two big problems: 1890 * 1. Not simplex devices are handled properly. 1891 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1892 * called with rcu_read_lock() 1893 */ 1894 1895 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1896 u8 tos, struct net_device *dev, 1897 struct fib_result *res) 1898 { 1899 struct in_device *in_dev = __in_dev_get_rcu(dev); 1900 struct flow_keys *flkeys = NULL, _flkeys; 1901 struct net *net = dev_net(dev); 1902 struct ip_tunnel_info *tun_info; 1903 int err = -EINVAL; 1904 unsigned int flags = 0; 1905 u32 itag = 0; 1906 struct rtable *rth; 1907 struct flowi4 fl4; 1908 bool do_cache; 1909 1910 /* IP on this device is disabled. */ 1911 1912 if (!in_dev) 1913 goto out; 1914 1915 /* Check for the most weird martians, which can be not detected 1916 by fib_lookup. 1917 */ 1918 1919 tun_info = skb_tunnel_info(skb); 1920 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1921 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1922 else 1923 fl4.flowi4_tun_key.tun_id = 0; 1924 skb_dst_drop(skb); 1925 1926 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1927 goto martian_source; 1928 1929 res->fi = NULL; 1930 res->table = NULL; 1931 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1932 goto brd_input; 1933 1934 /* Accept zero addresses only to limited broadcast; 1935 * I even do not know to fix it or not. Waiting for complains :-) 1936 */ 1937 if (ipv4_is_zeronet(saddr)) 1938 goto martian_source; 1939 1940 if (ipv4_is_zeronet(daddr)) 1941 goto martian_destination; 1942 1943 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1944 * and call it once if daddr or/and saddr are loopback addresses 1945 */ 1946 if (ipv4_is_loopback(daddr)) { 1947 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1948 goto martian_destination; 1949 } else if (ipv4_is_loopback(saddr)) { 1950 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1951 goto martian_source; 1952 } 1953 1954 /* 1955 * Now we are ready to route packet. 1956 */ 1957 fl4.flowi4_oif = 0; 1958 fl4.flowi4_iif = dev->ifindex; 1959 fl4.flowi4_mark = skb->mark; 1960 fl4.flowi4_tos = tos; 1961 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1962 fl4.flowi4_flags = 0; 1963 fl4.daddr = daddr; 1964 fl4.saddr = saddr; 1965 fl4.flowi4_uid = sock_net_uid(net, NULL); 1966 1967 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) 1968 flkeys = &_flkeys; 1969 1970 err = fib_lookup(net, &fl4, res, 0); 1971 if (err != 0) { 1972 if (!IN_DEV_FORWARD(in_dev)) 1973 err = -EHOSTUNREACH; 1974 goto no_route; 1975 } 1976 1977 if (res->type == RTN_BROADCAST) 1978 goto brd_input; 1979 1980 if (res->type == RTN_LOCAL) { 1981 err = fib_validate_source(skb, saddr, daddr, tos, 1982 0, dev, in_dev, &itag); 1983 if (err < 0) 1984 goto martian_source; 1985 goto local_input; 1986 } 1987 1988 if (!IN_DEV_FORWARD(in_dev)) { 1989 err = -EHOSTUNREACH; 1990 goto no_route; 1991 } 1992 if (res->type != RTN_UNICAST) 1993 goto martian_destination; 1994 1995 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 1996 out: return err; 1997 1998 brd_input: 1999 if (skb->protocol != htons(ETH_P_IP)) 2000 goto e_inval; 2001 2002 if (!ipv4_is_zeronet(saddr)) { 2003 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2004 in_dev, &itag); 2005 if (err < 0) 2006 goto martian_source; 2007 } 2008 flags |= RTCF_BROADCAST; 2009 res->type = RTN_BROADCAST; 2010 RT_CACHE_STAT_INC(in_brd); 2011 2012 local_input: 2013 do_cache = false; 2014 if (res->fi) { 2015 if (!itag) { 2016 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 2017 if (rt_cache_valid(rth)) { 2018 skb_dst_set_noref(skb, &rth->dst); 2019 err = 0; 2020 goto out; 2021 } 2022 do_cache = true; 2023 } 2024 } 2025 2026 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2027 flags | RTCF_LOCAL, res->type, 2028 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2029 if (!rth) 2030 goto e_nobufs; 2031 2032 rth->dst.output= ip_rt_bug; 2033 #ifdef CONFIG_IP_ROUTE_CLASSID 2034 rth->dst.tclassid = itag; 2035 #endif 2036 rth->rt_is_input = 1; 2037 2038 RT_CACHE_STAT_INC(in_slow_tot); 2039 if (res->type == RTN_UNREACHABLE) { 2040 rth->dst.input= ip_error; 2041 rth->dst.error= -err; 2042 rth->rt_flags &= ~RTCF_LOCAL; 2043 } 2044 2045 if (do_cache) { 2046 struct fib_nh *nh = &FIB_RES_NH(*res); 2047 2048 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 2049 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2050 WARN_ON(rth->dst.input == lwtunnel_input); 2051 rth->dst.lwtstate->orig_input = rth->dst.input; 2052 rth->dst.input = lwtunnel_input; 2053 } 2054 2055 if (unlikely(!rt_cache_route(nh, rth))) 2056 rt_add_uncached_list(rth); 2057 } 2058 skb_dst_set(skb, &rth->dst); 2059 err = 0; 2060 goto out; 2061 2062 no_route: 2063 RT_CACHE_STAT_INC(in_no_route); 2064 res->type = RTN_UNREACHABLE; 2065 res->fi = NULL; 2066 res->table = NULL; 2067 goto local_input; 2068 2069 /* 2070 * Do not cache martian addresses: they should be logged (RFC1812) 2071 */ 2072 martian_destination: 2073 RT_CACHE_STAT_INC(in_martian_dst); 2074 #ifdef CONFIG_IP_ROUTE_VERBOSE 2075 if (IN_DEV_LOG_MARTIANS(in_dev)) 2076 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2077 &daddr, &saddr, dev->name); 2078 #endif 2079 2080 e_inval: 2081 err = -EINVAL; 2082 goto out; 2083 2084 e_nobufs: 2085 err = -ENOBUFS; 2086 goto out; 2087 2088 martian_source: 2089 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2090 goto out; 2091 } 2092 2093 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2094 u8 tos, struct net_device *dev) 2095 { 2096 struct fib_result res; 2097 int err; 2098 2099 tos &= IPTOS_RT_MASK; 2100 rcu_read_lock(); 2101 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2102 rcu_read_unlock(); 2103 2104 return err; 2105 } 2106 EXPORT_SYMBOL(ip_route_input_noref); 2107 2108 /* called with rcu_read_lock held */ 2109 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2110 u8 tos, struct net_device *dev, struct fib_result *res) 2111 { 2112 /* Multicast recognition logic is moved from route cache to here. 2113 The problem was that too many Ethernet cards have broken/missing 2114 hardware multicast filters :-( As result the host on multicasting 2115 network acquires a lot of useless route cache entries, sort of 2116 SDR messages from all the world. Now we try to get rid of them. 2117 Really, provided software IP multicast filter is organized 2118 reasonably (at least, hashed), it does not result in a slowdown 2119 comparing with route cache reject entries. 2120 Note, that multicast routers are not affected, because 2121 route cache entry is created eventually. 2122 */ 2123 if (ipv4_is_multicast(daddr)) { 2124 struct in_device *in_dev = __in_dev_get_rcu(dev); 2125 int our = 0; 2126 int err = -EINVAL; 2127 2128 if (in_dev) 2129 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2130 ip_hdr(skb)->protocol); 2131 2132 /* check l3 master if no match yet */ 2133 if ((!in_dev || !our) && netif_is_l3_slave(dev)) { 2134 struct in_device *l3_in_dev; 2135 2136 l3_in_dev = __in_dev_get_rcu(skb->dev); 2137 if (l3_in_dev) 2138 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2139 ip_hdr(skb)->protocol); 2140 } 2141 2142 if (our 2143 #ifdef CONFIG_IP_MROUTE 2144 || 2145 (!ipv4_is_local_multicast(daddr) && 2146 IN_DEV_MFORWARD(in_dev)) 2147 #endif 2148 ) { 2149 err = ip_route_input_mc(skb, daddr, saddr, 2150 tos, dev, our); 2151 } 2152 return err; 2153 } 2154 2155 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2156 } 2157 2158 /* called with rcu_read_lock() */ 2159 static struct rtable *__mkroute_output(const struct fib_result *res, 2160 const struct flowi4 *fl4, int orig_oif, 2161 struct net_device *dev_out, 2162 unsigned int flags) 2163 { 2164 struct fib_info *fi = res->fi; 2165 struct fib_nh_exception *fnhe; 2166 struct in_device *in_dev; 2167 u16 type = res->type; 2168 struct rtable *rth; 2169 bool do_cache; 2170 2171 in_dev = __in_dev_get_rcu(dev_out); 2172 if (!in_dev) 2173 return ERR_PTR(-EINVAL); 2174 2175 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2176 if (ipv4_is_loopback(fl4->saddr) && 2177 !(dev_out->flags & IFF_LOOPBACK) && 2178 !netif_is_l3_master(dev_out)) 2179 return ERR_PTR(-EINVAL); 2180 2181 if (ipv4_is_lbcast(fl4->daddr)) 2182 type = RTN_BROADCAST; 2183 else if (ipv4_is_multicast(fl4->daddr)) 2184 type = RTN_MULTICAST; 2185 else if (ipv4_is_zeronet(fl4->daddr)) 2186 return ERR_PTR(-EINVAL); 2187 2188 if (dev_out->flags & IFF_LOOPBACK) 2189 flags |= RTCF_LOCAL; 2190 2191 do_cache = true; 2192 if (type == RTN_BROADCAST) { 2193 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2194 fi = NULL; 2195 } else if (type == RTN_MULTICAST) { 2196 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2197 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2198 fl4->flowi4_proto)) 2199 flags &= ~RTCF_LOCAL; 2200 else 2201 do_cache = false; 2202 /* If multicast route do not exist use 2203 * default one, but do not gateway in this case. 2204 * Yes, it is hack. 2205 */ 2206 if (fi && res->prefixlen < 4) 2207 fi = NULL; 2208 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2209 (orig_oif != dev_out->ifindex)) { 2210 /* For local routes that require a particular output interface 2211 * we do not want to cache the result. Caching the result 2212 * causes incorrect behaviour when there are multiple source 2213 * addresses on the interface, the end result being that if the 2214 * intended recipient is waiting on that interface for the 2215 * packet he won't receive it because it will be delivered on 2216 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2217 * be set to the loopback interface as well. 2218 */ 2219 fi = NULL; 2220 } 2221 2222 fnhe = NULL; 2223 do_cache &= fi != NULL; 2224 if (do_cache) { 2225 struct rtable __rcu **prth; 2226 struct fib_nh *nh = &FIB_RES_NH(*res); 2227 2228 fnhe = find_exception(nh, fl4->daddr); 2229 if (fnhe) { 2230 prth = &fnhe->fnhe_rth_output; 2231 rth = rcu_dereference(*prth); 2232 if (rth && rth->dst.expires && 2233 time_after(jiffies, rth->dst.expires)) { 2234 ip_del_fnhe(nh, fl4->daddr); 2235 fnhe = NULL; 2236 } else { 2237 goto rt_cache; 2238 } 2239 } 2240 2241 if (unlikely(fl4->flowi4_flags & 2242 FLOWI_FLAG_KNOWN_NH && 2243 !(nh->nh_gw && 2244 nh->nh_scope == RT_SCOPE_LINK))) { 2245 do_cache = false; 2246 goto add; 2247 } 2248 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2249 rth = rcu_dereference(*prth); 2250 2251 rt_cache: 2252 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2253 return rth; 2254 } 2255 2256 add: 2257 rth = rt_dst_alloc(dev_out, flags, type, 2258 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2259 IN_DEV_CONF_GET(in_dev, NOXFRM), 2260 do_cache); 2261 if (!rth) 2262 return ERR_PTR(-ENOBUFS); 2263 2264 rth->rt_iif = orig_oif; 2265 2266 RT_CACHE_STAT_INC(out_slow_tot); 2267 2268 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2269 if (flags & RTCF_LOCAL && 2270 !(dev_out->flags & IFF_LOOPBACK)) { 2271 rth->dst.output = ip_mc_output; 2272 RT_CACHE_STAT_INC(out_slow_mc); 2273 } 2274 #ifdef CONFIG_IP_MROUTE 2275 if (type == RTN_MULTICAST) { 2276 if (IN_DEV_MFORWARD(in_dev) && 2277 !ipv4_is_local_multicast(fl4->daddr)) { 2278 rth->dst.input = ip_mr_input; 2279 rth->dst.output = ip_mc_output; 2280 } 2281 } 2282 #endif 2283 } 2284 2285 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2286 lwtunnel_set_redirect(&rth->dst); 2287 2288 return rth; 2289 } 2290 2291 /* 2292 * Major route resolver routine. 2293 */ 2294 2295 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2296 const struct sk_buff *skb) 2297 { 2298 __u8 tos = RT_FL_TOS(fl4); 2299 struct fib_result res = { 2300 .type = RTN_UNSPEC, 2301 .fi = NULL, 2302 .table = NULL, 2303 .tclassid = 0, 2304 }; 2305 struct rtable *rth; 2306 2307 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2308 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2309 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2310 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2311 2312 rcu_read_lock(); 2313 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2314 rcu_read_unlock(); 2315 2316 return rth; 2317 } 2318 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2319 2320 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2321 struct fib_result *res, 2322 const struct sk_buff *skb) 2323 { 2324 struct net_device *dev_out = NULL; 2325 int orig_oif = fl4->flowi4_oif; 2326 unsigned int flags = 0; 2327 struct rtable *rth; 2328 int err = -ENETUNREACH; 2329 2330 if (fl4->saddr) { 2331 rth = ERR_PTR(-EINVAL); 2332 if (ipv4_is_multicast(fl4->saddr) || 2333 ipv4_is_lbcast(fl4->saddr) || 2334 ipv4_is_zeronet(fl4->saddr)) 2335 goto out; 2336 2337 /* I removed check for oif == dev_out->oif here. 2338 It was wrong for two reasons: 2339 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2340 is assigned to multiple interfaces. 2341 2. Moreover, we are allowed to send packets with saddr 2342 of another iface. --ANK 2343 */ 2344 2345 if (fl4->flowi4_oif == 0 && 2346 (ipv4_is_multicast(fl4->daddr) || 2347 ipv4_is_lbcast(fl4->daddr))) { 2348 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2349 dev_out = __ip_dev_find(net, fl4->saddr, false); 2350 if (!dev_out) 2351 goto out; 2352 2353 /* Special hack: user can direct multicasts 2354 and limited broadcast via necessary interface 2355 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2356 This hack is not just for fun, it allows 2357 vic,vat and friends to work. 2358 They bind socket to loopback, set ttl to zero 2359 and expect that it will work. 2360 From the viewpoint of routing cache they are broken, 2361 because we are not allowed to build multicast path 2362 with loopback source addr (look, routing cache 2363 cannot know, that ttl is zero, so that packet 2364 will not leave this host and route is valid). 2365 Luckily, this hack is good workaround. 2366 */ 2367 2368 fl4->flowi4_oif = dev_out->ifindex; 2369 goto make_route; 2370 } 2371 2372 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2373 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2374 if (!__ip_dev_find(net, fl4->saddr, false)) 2375 goto out; 2376 } 2377 } 2378 2379 2380 if (fl4->flowi4_oif) { 2381 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2382 rth = ERR_PTR(-ENODEV); 2383 if (!dev_out) 2384 goto out; 2385 2386 /* RACE: Check return value of inet_select_addr instead. */ 2387 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2388 rth = ERR_PTR(-ENETUNREACH); 2389 goto out; 2390 } 2391 if (ipv4_is_local_multicast(fl4->daddr) || 2392 ipv4_is_lbcast(fl4->daddr) || 2393 fl4->flowi4_proto == IPPROTO_IGMP) { 2394 if (!fl4->saddr) 2395 fl4->saddr = inet_select_addr(dev_out, 0, 2396 RT_SCOPE_LINK); 2397 goto make_route; 2398 } 2399 if (!fl4->saddr) { 2400 if (ipv4_is_multicast(fl4->daddr)) 2401 fl4->saddr = inet_select_addr(dev_out, 0, 2402 fl4->flowi4_scope); 2403 else if (!fl4->daddr) 2404 fl4->saddr = inet_select_addr(dev_out, 0, 2405 RT_SCOPE_HOST); 2406 } 2407 } 2408 2409 if (!fl4->daddr) { 2410 fl4->daddr = fl4->saddr; 2411 if (!fl4->daddr) 2412 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2413 dev_out = net->loopback_dev; 2414 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2415 res->type = RTN_LOCAL; 2416 flags |= RTCF_LOCAL; 2417 goto make_route; 2418 } 2419 2420 err = fib_lookup(net, fl4, res, 0); 2421 if (err) { 2422 res->fi = NULL; 2423 res->table = NULL; 2424 if (fl4->flowi4_oif && 2425 (ipv4_is_multicast(fl4->daddr) || 2426 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2427 /* Apparently, routing tables are wrong. Assume, 2428 that the destination is on link. 2429 2430 WHY? DW. 2431 Because we are allowed to send to iface 2432 even if it has NO routes and NO assigned 2433 addresses. When oif is specified, routing 2434 tables are looked up with only one purpose: 2435 to catch if destination is gatewayed, rather than 2436 direct. Moreover, if MSG_DONTROUTE is set, 2437 we send packet, ignoring both routing tables 2438 and ifaddr state. --ANK 2439 2440 2441 We could make it even if oif is unknown, 2442 likely IPv6, but we do not. 2443 */ 2444 2445 if (fl4->saddr == 0) 2446 fl4->saddr = inet_select_addr(dev_out, 0, 2447 RT_SCOPE_LINK); 2448 res->type = RTN_UNICAST; 2449 goto make_route; 2450 } 2451 rth = ERR_PTR(err); 2452 goto out; 2453 } 2454 2455 if (res->type == RTN_LOCAL) { 2456 if (!fl4->saddr) { 2457 if (res->fi->fib_prefsrc) 2458 fl4->saddr = res->fi->fib_prefsrc; 2459 else 2460 fl4->saddr = fl4->daddr; 2461 } 2462 2463 /* L3 master device is the loopback for that domain */ 2464 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2465 net->loopback_dev; 2466 2467 /* make sure orig_oif points to fib result device even 2468 * though packet rx/tx happens over loopback or l3mdev 2469 */ 2470 orig_oif = FIB_RES_OIF(*res); 2471 2472 fl4->flowi4_oif = dev_out->ifindex; 2473 flags |= RTCF_LOCAL; 2474 goto make_route; 2475 } 2476 2477 fib_select_path(net, res, fl4, skb); 2478 2479 dev_out = FIB_RES_DEV(*res); 2480 fl4->flowi4_oif = dev_out->ifindex; 2481 2482 2483 make_route: 2484 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2485 2486 out: 2487 return rth; 2488 } 2489 2490 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2491 { 2492 return NULL; 2493 } 2494 2495 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2496 { 2497 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2498 2499 return mtu ? : dst->dev->mtu; 2500 } 2501 2502 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2503 struct sk_buff *skb, u32 mtu) 2504 { 2505 } 2506 2507 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2508 struct sk_buff *skb) 2509 { 2510 } 2511 2512 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2513 unsigned long old) 2514 { 2515 return NULL; 2516 } 2517 2518 static struct dst_ops ipv4_dst_blackhole_ops = { 2519 .family = AF_INET, 2520 .check = ipv4_blackhole_dst_check, 2521 .mtu = ipv4_blackhole_mtu, 2522 .default_advmss = ipv4_default_advmss, 2523 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2524 .redirect = ipv4_rt_blackhole_redirect, 2525 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2526 .neigh_lookup = ipv4_neigh_lookup, 2527 }; 2528 2529 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2530 { 2531 struct rtable *ort = (struct rtable *) dst_orig; 2532 struct rtable *rt; 2533 2534 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2535 if (rt) { 2536 struct dst_entry *new = &rt->dst; 2537 2538 new->__use = 1; 2539 new->input = dst_discard; 2540 new->output = dst_discard_out; 2541 2542 new->dev = net->loopback_dev; 2543 if (new->dev) 2544 dev_hold(new->dev); 2545 2546 rt->rt_is_input = ort->rt_is_input; 2547 rt->rt_iif = ort->rt_iif; 2548 rt->rt_pmtu = ort->rt_pmtu; 2549 rt->rt_mtu_locked = ort->rt_mtu_locked; 2550 2551 rt->rt_genid = rt_genid_ipv4(net); 2552 rt->rt_flags = ort->rt_flags; 2553 rt->rt_type = ort->rt_type; 2554 rt->rt_gateway = ort->rt_gateway; 2555 rt->rt_uses_gateway = ort->rt_uses_gateway; 2556 2557 INIT_LIST_HEAD(&rt->rt_uncached); 2558 } 2559 2560 dst_release(dst_orig); 2561 2562 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2563 } 2564 2565 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2566 const struct sock *sk) 2567 { 2568 struct rtable *rt = __ip_route_output_key(net, flp4); 2569 2570 if (IS_ERR(rt)) 2571 return rt; 2572 2573 if (flp4->flowi4_proto) 2574 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2575 flowi4_to_flowi(flp4), 2576 sk, 0); 2577 2578 return rt; 2579 } 2580 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2581 2582 /* called with rcu_read_lock held */ 2583 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2584 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2585 u32 seq) 2586 { 2587 struct rtable *rt = skb_rtable(skb); 2588 struct rtmsg *r; 2589 struct nlmsghdr *nlh; 2590 unsigned long expires = 0; 2591 u32 error; 2592 u32 metrics[RTAX_MAX]; 2593 2594 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0); 2595 if (!nlh) 2596 return -EMSGSIZE; 2597 2598 r = nlmsg_data(nlh); 2599 r->rtm_family = AF_INET; 2600 r->rtm_dst_len = 32; 2601 r->rtm_src_len = 0; 2602 r->rtm_tos = fl4->flowi4_tos; 2603 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2604 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2605 goto nla_put_failure; 2606 r->rtm_type = rt->rt_type; 2607 r->rtm_scope = RT_SCOPE_UNIVERSE; 2608 r->rtm_protocol = RTPROT_UNSPEC; 2609 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2610 if (rt->rt_flags & RTCF_NOTIFY) 2611 r->rtm_flags |= RTM_F_NOTIFY; 2612 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2613 r->rtm_flags |= RTCF_DOREDIRECT; 2614 2615 if (nla_put_in_addr(skb, RTA_DST, dst)) 2616 goto nla_put_failure; 2617 if (src) { 2618 r->rtm_src_len = 32; 2619 if (nla_put_in_addr(skb, RTA_SRC, src)) 2620 goto nla_put_failure; 2621 } 2622 if (rt->dst.dev && 2623 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2624 goto nla_put_failure; 2625 #ifdef CONFIG_IP_ROUTE_CLASSID 2626 if (rt->dst.tclassid && 2627 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2628 goto nla_put_failure; 2629 #endif 2630 if (!rt_is_input_route(rt) && 2631 fl4->saddr != src) { 2632 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2633 goto nla_put_failure; 2634 } 2635 if (rt->rt_uses_gateway && 2636 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2637 goto nla_put_failure; 2638 2639 expires = rt->dst.expires; 2640 if (expires) { 2641 unsigned long now = jiffies; 2642 2643 if (time_before(now, expires)) 2644 expires -= now; 2645 else 2646 expires = 0; 2647 } 2648 2649 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2650 if (rt->rt_pmtu && expires) 2651 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2652 if (rt->rt_mtu_locked && expires) 2653 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2654 if (rtnetlink_put_metrics(skb, metrics) < 0) 2655 goto nla_put_failure; 2656 2657 if (fl4->flowi4_mark && 2658 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2659 goto nla_put_failure; 2660 2661 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2662 nla_put_u32(skb, RTA_UID, 2663 from_kuid_munged(current_user_ns(), fl4->flowi4_uid))) 2664 goto nla_put_failure; 2665 2666 error = rt->dst.error; 2667 2668 if (rt_is_input_route(rt)) { 2669 #ifdef CONFIG_IP_MROUTE 2670 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2671 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2672 int err = ipmr_get_route(net, skb, 2673 fl4->saddr, fl4->daddr, 2674 r, portid); 2675 2676 if (err <= 0) { 2677 if (err == 0) 2678 return 0; 2679 goto nla_put_failure; 2680 } 2681 } else 2682 #endif 2683 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2684 goto nla_put_failure; 2685 } 2686 2687 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2688 goto nla_put_failure; 2689 2690 nlmsg_end(skb, nlh); 2691 return 0; 2692 2693 nla_put_failure: 2694 nlmsg_cancel(skb, nlh); 2695 return -EMSGSIZE; 2696 } 2697 2698 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 2699 struct netlink_ext_ack *extack) 2700 { 2701 struct net *net = sock_net(in_skb->sk); 2702 struct rtmsg *rtm; 2703 struct nlattr *tb[RTA_MAX+1]; 2704 struct fib_result res = {}; 2705 struct rtable *rt = NULL; 2706 struct flowi4 fl4; 2707 __be32 dst = 0; 2708 __be32 src = 0; 2709 u32 iif; 2710 int err; 2711 int mark; 2712 struct sk_buff *skb; 2713 u32 table_id = RT_TABLE_MAIN; 2714 kuid_t uid; 2715 2716 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy, 2717 extack); 2718 if (err < 0) 2719 goto errout; 2720 2721 rtm = nlmsg_data(nlh); 2722 2723 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2724 if (!skb) { 2725 err = -ENOBUFS; 2726 goto errout; 2727 } 2728 2729 /* Reserve room for dummy headers, this skb can pass 2730 through good chunk of routing engine. 2731 */ 2732 skb_reset_mac_header(skb); 2733 skb_reset_network_header(skb); 2734 2735 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2736 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2737 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2738 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2739 if (tb[RTA_UID]) 2740 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 2741 else 2742 uid = (iif ? INVALID_UID : current_uid()); 2743 2744 /* Bugfix: need to give ip_route_input enough of an IP header to 2745 * not gag. 2746 */ 2747 ip_hdr(skb)->protocol = IPPROTO_UDP; 2748 ip_hdr(skb)->saddr = src; 2749 ip_hdr(skb)->daddr = dst; 2750 2751 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2752 2753 memset(&fl4, 0, sizeof(fl4)); 2754 fl4.daddr = dst; 2755 fl4.saddr = src; 2756 fl4.flowi4_tos = rtm->rtm_tos; 2757 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2758 fl4.flowi4_mark = mark; 2759 fl4.flowi4_uid = uid; 2760 2761 rcu_read_lock(); 2762 2763 if (iif) { 2764 struct net_device *dev; 2765 2766 dev = dev_get_by_index_rcu(net, iif); 2767 if (!dev) { 2768 err = -ENODEV; 2769 goto errout_free; 2770 } 2771 2772 skb->protocol = htons(ETH_P_IP); 2773 skb->dev = dev; 2774 skb->mark = mark; 2775 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 2776 dev, &res); 2777 2778 rt = skb_rtable(skb); 2779 if (err == 0 && rt->dst.error) 2780 err = -rt->dst.error; 2781 } else { 2782 fl4.flowi4_iif = LOOPBACK_IFINDEX; 2783 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 2784 err = 0; 2785 if (IS_ERR(rt)) 2786 err = PTR_ERR(rt); 2787 else 2788 skb_dst_set(skb, &rt->dst); 2789 } 2790 2791 if (err) 2792 goto errout_free; 2793 2794 if (rtm->rtm_flags & RTM_F_NOTIFY) 2795 rt->rt_flags |= RTCF_NOTIFY; 2796 2797 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2798 table_id = res.table ? res.table->tb_id : 0; 2799 2800 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 2801 if (!res.fi) { 2802 err = fib_props[res.type].error; 2803 if (!err) 2804 err = -EHOSTUNREACH; 2805 goto errout_free; 2806 } 2807 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 2808 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 2809 rt->rt_type, res.prefix, res.prefixlen, 2810 fl4.flowi4_tos, res.fi, 0); 2811 } else { 2812 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2813 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq); 2814 } 2815 if (err < 0) 2816 goto errout_free; 2817 2818 rcu_read_unlock(); 2819 2820 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2821 errout: 2822 return err; 2823 2824 errout_free: 2825 rcu_read_unlock(); 2826 kfree_skb(skb); 2827 goto errout; 2828 } 2829 2830 void ip_rt_multicast_event(struct in_device *in_dev) 2831 { 2832 rt_cache_flush(dev_net(in_dev->dev)); 2833 } 2834 2835 #ifdef CONFIG_SYSCTL 2836 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2837 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2838 static int ip_rt_gc_elasticity __read_mostly = 8; 2839 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 2840 2841 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2842 void __user *buffer, 2843 size_t *lenp, loff_t *ppos) 2844 { 2845 struct net *net = (struct net *)__ctl->extra1; 2846 2847 if (write) { 2848 rt_cache_flush(net); 2849 fnhe_genid_bump(net); 2850 return 0; 2851 } 2852 2853 return -EINVAL; 2854 } 2855 2856 static struct ctl_table ipv4_route_table[] = { 2857 { 2858 .procname = "gc_thresh", 2859 .data = &ipv4_dst_ops.gc_thresh, 2860 .maxlen = sizeof(int), 2861 .mode = 0644, 2862 .proc_handler = proc_dointvec, 2863 }, 2864 { 2865 .procname = "max_size", 2866 .data = &ip_rt_max_size, 2867 .maxlen = sizeof(int), 2868 .mode = 0644, 2869 .proc_handler = proc_dointvec, 2870 }, 2871 { 2872 /* Deprecated. Use gc_min_interval_ms */ 2873 2874 .procname = "gc_min_interval", 2875 .data = &ip_rt_gc_min_interval, 2876 .maxlen = sizeof(int), 2877 .mode = 0644, 2878 .proc_handler = proc_dointvec_jiffies, 2879 }, 2880 { 2881 .procname = "gc_min_interval_ms", 2882 .data = &ip_rt_gc_min_interval, 2883 .maxlen = sizeof(int), 2884 .mode = 0644, 2885 .proc_handler = proc_dointvec_ms_jiffies, 2886 }, 2887 { 2888 .procname = "gc_timeout", 2889 .data = &ip_rt_gc_timeout, 2890 .maxlen = sizeof(int), 2891 .mode = 0644, 2892 .proc_handler = proc_dointvec_jiffies, 2893 }, 2894 { 2895 .procname = "gc_interval", 2896 .data = &ip_rt_gc_interval, 2897 .maxlen = sizeof(int), 2898 .mode = 0644, 2899 .proc_handler = proc_dointvec_jiffies, 2900 }, 2901 { 2902 .procname = "redirect_load", 2903 .data = &ip_rt_redirect_load, 2904 .maxlen = sizeof(int), 2905 .mode = 0644, 2906 .proc_handler = proc_dointvec, 2907 }, 2908 { 2909 .procname = "redirect_number", 2910 .data = &ip_rt_redirect_number, 2911 .maxlen = sizeof(int), 2912 .mode = 0644, 2913 .proc_handler = proc_dointvec, 2914 }, 2915 { 2916 .procname = "redirect_silence", 2917 .data = &ip_rt_redirect_silence, 2918 .maxlen = sizeof(int), 2919 .mode = 0644, 2920 .proc_handler = proc_dointvec, 2921 }, 2922 { 2923 .procname = "error_cost", 2924 .data = &ip_rt_error_cost, 2925 .maxlen = sizeof(int), 2926 .mode = 0644, 2927 .proc_handler = proc_dointvec, 2928 }, 2929 { 2930 .procname = "error_burst", 2931 .data = &ip_rt_error_burst, 2932 .maxlen = sizeof(int), 2933 .mode = 0644, 2934 .proc_handler = proc_dointvec, 2935 }, 2936 { 2937 .procname = "gc_elasticity", 2938 .data = &ip_rt_gc_elasticity, 2939 .maxlen = sizeof(int), 2940 .mode = 0644, 2941 .proc_handler = proc_dointvec, 2942 }, 2943 { 2944 .procname = "mtu_expires", 2945 .data = &ip_rt_mtu_expires, 2946 .maxlen = sizeof(int), 2947 .mode = 0644, 2948 .proc_handler = proc_dointvec_jiffies, 2949 }, 2950 { 2951 .procname = "min_pmtu", 2952 .data = &ip_rt_min_pmtu, 2953 .maxlen = sizeof(int), 2954 .mode = 0644, 2955 .proc_handler = proc_dointvec_minmax, 2956 .extra1 = &ip_min_valid_pmtu, 2957 }, 2958 { 2959 .procname = "min_adv_mss", 2960 .data = &ip_rt_min_advmss, 2961 .maxlen = sizeof(int), 2962 .mode = 0644, 2963 .proc_handler = proc_dointvec, 2964 }, 2965 { } 2966 }; 2967 2968 static struct ctl_table ipv4_route_flush_table[] = { 2969 { 2970 .procname = "flush", 2971 .maxlen = sizeof(int), 2972 .mode = 0200, 2973 .proc_handler = ipv4_sysctl_rtcache_flush, 2974 }, 2975 { }, 2976 }; 2977 2978 static __net_init int sysctl_route_net_init(struct net *net) 2979 { 2980 struct ctl_table *tbl; 2981 2982 tbl = ipv4_route_flush_table; 2983 if (!net_eq(net, &init_net)) { 2984 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2985 if (!tbl) 2986 goto err_dup; 2987 2988 /* Don't export sysctls to unprivileged users */ 2989 if (net->user_ns != &init_user_ns) 2990 tbl[0].procname = NULL; 2991 } 2992 tbl[0].extra1 = net; 2993 2994 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2995 if (!net->ipv4.route_hdr) 2996 goto err_reg; 2997 return 0; 2998 2999 err_reg: 3000 if (tbl != ipv4_route_flush_table) 3001 kfree(tbl); 3002 err_dup: 3003 return -ENOMEM; 3004 } 3005 3006 static __net_exit void sysctl_route_net_exit(struct net *net) 3007 { 3008 struct ctl_table *tbl; 3009 3010 tbl = net->ipv4.route_hdr->ctl_table_arg; 3011 unregister_net_sysctl_table(net->ipv4.route_hdr); 3012 BUG_ON(tbl == ipv4_route_flush_table); 3013 kfree(tbl); 3014 } 3015 3016 static __net_initdata struct pernet_operations sysctl_route_ops = { 3017 .init = sysctl_route_net_init, 3018 .exit = sysctl_route_net_exit, 3019 }; 3020 #endif 3021 3022 static __net_init int rt_genid_init(struct net *net) 3023 { 3024 atomic_set(&net->ipv4.rt_genid, 0); 3025 atomic_set(&net->fnhe_genid, 0); 3026 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3027 return 0; 3028 } 3029 3030 static __net_initdata struct pernet_operations rt_genid_ops = { 3031 .init = rt_genid_init, 3032 }; 3033 3034 static int __net_init ipv4_inetpeer_init(struct net *net) 3035 { 3036 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3037 3038 if (!bp) 3039 return -ENOMEM; 3040 inet_peer_base_init(bp); 3041 net->ipv4.peers = bp; 3042 return 0; 3043 } 3044 3045 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3046 { 3047 struct inet_peer_base *bp = net->ipv4.peers; 3048 3049 net->ipv4.peers = NULL; 3050 inetpeer_invalidate_tree(bp); 3051 kfree(bp); 3052 } 3053 3054 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3055 .init = ipv4_inetpeer_init, 3056 .exit = ipv4_inetpeer_exit, 3057 }; 3058 3059 #ifdef CONFIG_IP_ROUTE_CLASSID 3060 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3061 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3062 3063 int __init ip_rt_init(void) 3064 { 3065 int cpu; 3066 3067 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 3068 if (!ip_idents) 3069 panic("IP: failed to allocate ip_idents\n"); 3070 3071 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3072 3073 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3074 if (!ip_tstamps) 3075 panic("IP: failed to allocate ip_tstamps\n"); 3076 3077 for_each_possible_cpu(cpu) { 3078 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3079 3080 INIT_LIST_HEAD(&ul->head); 3081 spin_lock_init(&ul->lock); 3082 } 3083 #ifdef CONFIG_IP_ROUTE_CLASSID 3084 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3085 if (!ip_rt_acct) 3086 panic("IP: failed to allocate ip_rt_acct\n"); 3087 #endif 3088 3089 ipv4_dst_ops.kmem_cachep = 3090 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3091 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3092 3093 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3094 3095 if (dst_entries_init(&ipv4_dst_ops) < 0) 3096 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3097 3098 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3099 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3100 3101 ipv4_dst_ops.gc_thresh = ~0; 3102 ip_rt_max_size = INT_MAX; 3103 3104 devinet_init(); 3105 ip_fib_init(); 3106 3107 if (ip_rt_proc_init()) 3108 pr_err("Unable to create route proc files\n"); 3109 #ifdef CONFIG_XFRM 3110 xfrm_init(); 3111 xfrm4_init(); 3112 #endif 3113 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3114 RTNL_FLAG_DOIT_UNLOCKED); 3115 3116 #ifdef CONFIG_SYSCTL 3117 register_pernet_subsys(&sysctl_route_ops); 3118 #endif 3119 register_pernet_subsys(&rt_genid_ops); 3120 register_pernet_subsys(&ipv4_inetpeer_ops); 3121 return 0; 3122 } 3123 3124 #ifdef CONFIG_SYSCTL 3125 /* 3126 * We really need to sanitize the damn ipv4 init order, then all 3127 * this nonsense will go away. 3128 */ 3129 void __init ip_static_sysctl_init(void) 3130 { 3131 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3132 } 3133 #endif 3134