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 #endif 364 365 static int __net_init ip_rt_do_proc_init(struct net *net) 366 { 367 struct proc_dir_entry *pde; 368 369 pde = proc_create("rt_cache", 0444, net->proc_net, 370 &rt_cache_seq_fops); 371 if (!pde) 372 goto err1; 373 374 pde = proc_create("rt_cache", 0444, 375 net->proc_net_stat, &rt_cpu_seq_fops); 376 if (!pde) 377 goto err2; 378 379 #ifdef CONFIG_IP_ROUTE_CLASSID 380 pde = proc_create_single("rt_acct", 0, net->proc_net, 381 rt_acct_proc_show); 382 if (!pde) 383 goto err3; 384 #endif 385 return 0; 386 387 #ifdef CONFIG_IP_ROUTE_CLASSID 388 err3: 389 remove_proc_entry("rt_cache", net->proc_net_stat); 390 #endif 391 err2: 392 remove_proc_entry("rt_cache", net->proc_net); 393 err1: 394 return -ENOMEM; 395 } 396 397 static void __net_exit ip_rt_do_proc_exit(struct net *net) 398 { 399 remove_proc_entry("rt_cache", net->proc_net_stat); 400 remove_proc_entry("rt_cache", net->proc_net); 401 #ifdef CONFIG_IP_ROUTE_CLASSID 402 remove_proc_entry("rt_acct", net->proc_net); 403 #endif 404 } 405 406 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 407 .init = ip_rt_do_proc_init, 408 .exit = ip_rt_do_proc_exit, 409 }; 410 411 static int __init ip_rt_proc_init(void) 412 { 413 return register_pernet_subsys(&ip_rt_proc_ops); 414 } 415 416 #else 417 static inline int ip_rt_proc_init(void) 418 { 419 return 0; 420 } 421 #endif /* CONFIG_PROC_FS */ 422 423 static inline bool rt_is_expired(const struct rtable *rth) 424 { 425 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 426 } 427 428 void rt_cache_flush(struct net *net) 429 { 430 rt_genid_bump_ipv4(net); 431 } 432 433 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 434 struct sk_buff *skb, 435 const void *daddr) 436 { 437 struct net_device *dev = dst->dev; 438 const __be32 *pkey = daddr; 439 const struct rtable *rt; 440 struct neighbour *n; 441 442 rt = (const struct rtable *) dst; 443 if (rt->rt_gateway) 444 pkey = (const __be32 *) &rt->rt_gateway; 445 else if (skb) 446 pkey = &ip_hdr(skb)->daddr; 447 448 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); 449 if (n) 450 return n; 451 return neigh_create(&arp_tbl, pkey, dev); 452 } 453 454 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 455 { 456 struct net_device *dev = dst->dev; 457 const __be32 *pkey = daddr; 458 const struct rtable *rt; 459 460 rt = (const struct rtable *)dst; 461 if (rt->rt_gateway) 462 pkey = (const __be32 *)&rt->rt_gateway; 463 else if (!daddr || 464 (rt->rt_flags & 465 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) 466 return; 467 468 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 469 } 470 471 #define IP_IDENTS_SZ 2048u 472 473 static atomic_t *ip_idents __read_mostly; 474 static u32 *ip_tstamps __read_mostly; 475 476 /* In order to protect privacy, we add a perturbation to identifiers 477 * if one generator is seldom used. This makes hard for an attacker 478 * to infer how many packets were sent between two points in time. 479 */ 480 u32 ip_idents_reserve(u32 hash, int segs) 481 { 482 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 483 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 484 u32 old = READ_ONCE(*p_tstamp); 485 u32 now = (u32)jiffies; 486 u32 new, delta = 0; 487 488 if (old != now && cmpxchg(p_tstamp, old, now) == old) 489 delta = prandom_u32_max(now - old); 490 491 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 492 do { 493 old = (u32)atomic_read(p_id); 494 new = old + delta + segs; 495 } while (atomic_cmpxchg(p_id, old, new) != old); 496 497 return new - segs; 498 } 499 EXPORT_SYMBOL(ip_idents_reserve); 500 501 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 502 { 503 static u32 ip_idents_hashrnd __read_mostly; 504 u32 hash, id; 505 506 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); 507 508 hash = jhash_3words((__force u32)iph->daddr, 509 (__force u32)iph->saddr, 510 iph->protocol ^ net_hash_mix(net), 511 ip_idents_hashrnd); 512 id = ip_idents_reserve(hash, segs); 513 iph->id = htons(id); 514 } 515 EXPORT_SYMBOL(__ip_select_ident); 516 517 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 518 const struct sock *sk, 519 const struct iphdr *iph, 520 int oif, u8 tos, 521 u8 prot, u32 mark, int flow_flags) 522 { 523 if (sk) { 524 const struct inet_sock *inet = inet_sk(sk); 525 526 oif = sk->sk_bound_dev_if; 527 mark = sk->sk_mark; 528 tos = RT_CONN_FLAGS(sk); 529 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 530 } 531 flowi4_init_output(fl4, oif, mark, tos, 532 RT_SCOPE_UNIVERSE, prot, 533 flow_flags, 534 iph->daddr, iph->saddr, 0, 0, 535 sock_net_uid(net, sk)); 536 } 537 538 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 539 const struct sock *sk) 540 { 541 const struct net *net = dev_net(skb->dev); 542 const struct iphdr *iph = ip_hdr(skb); 543 int oif = skb->dev->ifindex; 544 u8 tos = RT_TOS(iph->tos); 545 u8 prot = iph->protocol; 546 u32 mark = skb->mark; 547 548 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 549 } 550 551 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 552 { 553 const struct inet_sock *inet = inet_sk(sk); 554 const struct ip_options_rcu *inet_opt; 555 __be32 daddr = inet->inet_daddr; 556 557 rcu_read_lock(); 558 inet_opt = rcu_dereference(inet->inet_opt); 559 if (inet_opt && inet_opt->opt.srr) 560 daddr = inet_opt->opt.faddr; 561 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 562 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 563 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 564 inet_sk_flowi_flags(sk), 565 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 566 rcu_read_unlock(); 567 } 568 569 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 570 const struct sk_buff *skb) 571 { 572 if (skb) 573 build_skb_flow_key(fl4, skb, sk); 574 else 575 build_sk_flow_key(fl4, sk); 576 } 577 578 static DEFINE_SPINLOCK(fnhe_lock); 579 580 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 581 { 582 struct rtable *rt; 583 584 rt = rcu_dereference(fnhe->fnhe_rth_input); 585 if (rt) { 586 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 587 dst_dev_put(&rt->dst); 588 dst_release(&rt->dst); 589 } 590 rt = rcu_dereference(fnhe->fnhe_rth_output); 591 if (rt) { 592 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 593 dst_dev_put(&rt->dst); 594 dst_release(&rt->dst); 595 } 596 } 597 598 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 599 { 600 struct fib_nh_exception *fnhe, *oldest; 601 602 oldest = rcu_dereference(hash->chain); 603 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 604 fnhe = rcu_dereference(fnhe->fnhe_next)) { 605 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 606 oldest = fnhe; 607 } 608 fnhe_flush_routes(oldest); 609 return oldest; 610 } 611 612 static inline u32 fnhe_hashfun(__be32 daddr) 613 { 614 static u32 fnhe_hashrnd __read_mostly; 615 u32 hval; 616 617 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 618 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 619 return hash_32(hval, FNHE_HASH_SHIFT); 620 } 621 622 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 623 { 624 rt->rt_pmtu = fnhe->fnhe_pmtu; 625 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 626 rt->dst.expires = fnhe->fnhe_expires; 627 628 if (fnhe->fnhe_gw) { 629 rt->rt_flags |= RTCF_REDIRECTED; 630 rt->rt_gateway = fnhe->fnhe_gw; 631 rt->rt_uses_gateway = 1; 632 } 633 } 634 635 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 636 u32 pmtu, bool lock, unsigned long expires) 637 { 638 struct fnhe_hash_bucket *hash; 639 struct fib_nh_exception *fnhe; 640 struct rtable *rt; 641 u32 genid, hval; 642 unsigned int i; 643 int depth; 644 645 genid = fnhe_genid(dev_net(nh->nh_dev)); 646 hval = fnhe_hashfun(daddr); 647 648 spin_lock_bh(&fnhe_lock); 649 650 hash = rcu_dereference(nh->nh_exceptions); 651 if (!hash) { 652 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 653 if (!hash) 654 goto out_unlock; 655 rcu_assign_pointer(nh->nh_exceptions, hash); 656 } 657 658 hash += hval; 659 660 depth = 0; 661 for (fnhe = rcu_dereference(hash->chain); fnhe; 662 fnhe = rcu_dereference(fnhe->fnhe_next)) { 663 if (fnhe->fnhe_daddr == daddr) 664 break; 665 depth++; 666 } 667 668 if (fnhe) { 669 if (fnhe->fnhe_genid != genid) 670 fnhe->fnhe_genid = genid; 671 if (gw) 672 fnhe->fnhe_gw = gw; 673 if (pmtu) { 674 fnhe->fnhe_pmtu = pmtu; 675 fnhe->fnhe_mtu_locked = lock; 676 } 677 fnhe->fnhe_expires = max(1UL, expires); 678 /* Update all cached dsts too */ 679 rt = rcu_dereference(fnhe->fnhe_rth_input); 680 if (rt) 681 fill_route_from_fnhe(rt, fnhe); 682 rt = rcu_dereference(fnhe->fnhe_rth_output); 683 if (rt) 684 fill_route_from_fnhe(rt, fnhe); 685 } else { 686 if (depth > FNHE_RECLAIM_DEPTH) 687 fnhe = fnhe_oldest(hash); 688 else { 689 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 690 if (!fnhe) 691 goto out_unlock; 692 693 fnhe->fnhe_next = hash->chain; 694 rcu_assign_pointer(hash->chain, fnhe); 695 } 696 fnhe->fnhe_genid = genid; 697 fnhe->fnhe_daddr = daddr; 698 fnhe->fnhe_gw = gw; 699 fnhe->fnhe_pmtu = pmtu; 700 fnhe->fnhe_mtu_locked = lock; 701 fnhe->fnhe_expires = max(1UL, expires); 702 703 /* Exception created; mark the cached routes for the nexthop 704 * stale, so anyone caching it rechecks if this exception 705 * applies to them. 706 */ 707 rt = rcu_dereference(nh->nh_rth_input); 708 if (rt) 709 rt->dst.obsolete = DST_OBSOLETE_KILL; 710 711 for_each_possible_cpu(i) { 712 struct rtable __rcu **prt; 713 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 714 rt = rcu_dereference(*prt); 715 if (rt) 716 rt->dst.obsolete = DST_OBSOLETE_KILL; 717 } 718 } 719 720 fnhe->fnhe_stamp = jiffies; 721 722 out_unlock: 723 spin_unlock_bh(&fnhe_lock); 724 } 725 726 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 727 bool kill_route) 728 { 729 __be32 new_gw = icmp_hdr(skb)->un.gateway; 730 __be32 old_gw = ip_hdr(skb)->saddr; 731 struct net_device *dev = skb->dev; 732 struct in_device *in_dev; 733 struct fib_result res; 734 struct neighbour *n; 735 struct net *net; 736 737 switch (icmp_hdr(skb)->code & 7) { 738 case ICMP_REDIR_NET: 739 case ICMP_REDIR_NETTOS: 740 case ICMP_REDIR_HOST: 741 case ICMP_REDIR_HOSTTOS: 742 break; 743 744 default: 745 return; 746 } 747 748 if (rt->rt_gateway != old_gw) 749 return; 750 751 in_dev = __in_dev_get_rcu(dev); 752 if (!in_dev) 753 return; 754 755 net = dev_net(dev); 756 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 757 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 758 ipv4_is_zeronet(new_gw)) 759 goto reject_redirect; 760 761 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 762 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 763 goto reject_redirect; 764 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 765 goto reject_redirect; 766 } else { 767 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 768 goto reject_redirect; 769 } 770 771 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 772 if (!n) 773 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 774 if (!IS_ERR(n)) { 775 if (!(n->nud_state & NUD_VALID)) { 776 neigh_event_send(n, NULL); 777 } else { 778 if (fib_lookup(net, fl4, &res, 0) == 0) { 779 struct fib_nh *nh = &FIB_RES_NH(res); 780 781 update_or_create_fnhe(nh, fl4->daddr, new_gw, 782 0, false, 783 jiffies + ip_rt_gc_timeout); 784 } 785 if (kill_route) 786 rt->dst.obsolete = DST_OBSOLETE_KILL; 787 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 788 } 789 neigh_release(n); 790 } 791 return; 792 793 reject_redirect: 794 #ifdef CONFIG_IP_ROUTE_VERBOSE 795 if (IN_DEV_LOG_MARTIANS(in_dev)) { 796 const struct iphdr *iph = (const struct iphdr *) skb->data; 797 __be32 daddr = iph->daddr; 798 __be32 saddr = iph->saddr; 799 800 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 801 " Advised path = %pI4 -> %pI4\n", 802 &old_gw, dev->name, &new_gw, 803 &saddr, &daddr); 804 } 805 #endif 806 ; 807 } 808 809 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 810 { 811 struct rtable *rt; 812 struct flowi4 fl4; 813 const struct iphdr *iph = (const struct iphdr *) skb->data; 814 struct net *net = dev_net(skb->dev); 815 int oif = skb->dev->ifindex; 816 u8 tos = RT_TOS(iph->tos); 817 u8 prot = iph->protocol; 818 u32 mark = skb->mark; 819 820 rt = (struct rtable *) dst; 821 822 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 823 __ip_do_redirect(rt, skb, &fl4, true); 824 } 825 826 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 827 { 828 struct rtable *rt = (struct rtable *)dst; 829 struct dst_entry *ret = dst; 830 831 if (rt) { 832 if (dst->obsolete > 0) { 833 ip_rt_put(rt); 834 ret = NULL; 835 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 836 rt->dst.expires) { 837 ip_rt_put(rt); 838 ret = NULL; 839 } 840 } 841 return ret; 842 } 843 844 /* 845 * Algorithm: 846 * 1. The first ip_rt_redirect_number redirects are sent 847 * with exponential backoff, then we stop sending them at all, 848 * assuming that the host ignores our redirects. 849 * 2. If we did not see packets requiring redirects 850 * during ip_rt_redirect_silence, we assume that the host 851 * forgot redirected route and start to send redirects again. 852 * 853 * This algorithm is much cheaper and more intelligent than dumb load limiting 854 * in icmp.c. 855 * 856 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 857 * and "frag. need" (breaks PMTU discovery) in icmp.c. 858 */ 859 860 void ip_rt_send_redirect(struct sk_buff *skb) 861 { 862 struct rtable *rt = skb_rtable(skb); 863 struct in_device *in_dev; 864 struct inet_peer *peer; 865 struct net *net; 866 int log_martians; 867 int vif; 868 869 rcu_read_lock(); 870 in_dev = __in_dev_get_rcu(rt->dst.dev); 871 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 872 rcu_read_unlock(); 873 return; 874 } 875 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 876 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 877 rcu_read_unlock(); 878 879 net = dev_net(rt->dst.dev); 880 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 881 if (!peer) { 882 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 883 rt_nexthop(rt, ip_hdr(skb)->daddr)); 884 return; 885 } 886 887 /* No redirected packets during ip_rt_redirect_silence; 888 * reset the algorithm. 889 */ 890 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 891 peer->rate_tokens = 0; 892 893 /* Too many ignored redirects; do not send anything 894 * set dst.rate_last to the last seen redirected packet. 895 */ 896 if (peer->rate_tokens >= ip_rt_redirect_number) { 897 peer->rate_last = jiffies; 898 goto out_put_peer; 899 } 900 901 /* Check for load limit; set rate_last to the latest sent 902 * redirect. 903 */ 904 if (peer->rate_tokens == 0 || 905 time_after(jiffies, 906 (peer->rate_last + 907 (ip_rt_redirect_load << peer->rate_tokens)))) { 908 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 909 910 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 911 peer->rate_last = jiffies; 912 ++peer->rate_tokens; 913 #ifdef CONFIG_IP_ROUTE_VERBOSE 914 if (log_martians && 915 peer->rate_tokens == ip_rt_redirect_number) 916 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 917 &ip_hdr(skb)->saddr, inet_iif(skb), 918 &ip_hdr(skb)->daddr, &gw); 919 #endif 920 } 921 out_put_peer: 922 inet_putpeer(peer); 923 } 924 925 static int ip_error(struct sk_buff *skb) 926 { 927 struct rtable *rt = skb_rtable(skb); 928 struct net_device *dev = skb->dev; 929 struct in_device *in_dev; 930 struct inet_peer *peer; 931 unsigned long now; 932 struct net *net; 933 bool send; 934 int code; 935 936 if (netif_is_l3_master(skb->dev)) { 937 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 938 if (!dev) 939 goto out; 940 } 941 942 in_dev = __in_dev_get_rcu(dev); 943 944 /* IP on this device is disabled. */ 945 if (!in_dev) 946 goto out; 947 948 net = dev_net(rt->dst.dev); 949 if (!IN_DEV_FORWARD(in_dev)) { 950 switch (rt->dst.error) { 951 case EHOSTUNREACH: 952 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 953 break; 954 955 case ENETUNREACH: 956 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 957 break; 958 } 959 goto out; 960 } 961 962 switch (rt->dst.error) { 963 case EINVAL: 964 default: 965 goto out; 966 case EHOSTUNREACH: 967 code = ICMP_HOST_UNREACH; 968 break; 969 case ENETUNREACH: 970 code = ICMP_NET_UNREACH; 971 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 972 break; 973 case EACCES: 974 code = ICMP_PKT_FILTERED; 975 break; 976 } 977 978 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 979 l3mdev_master_ifindex(skb->dev), 1); 980 981 send = true; 982 if (peer) { 983 now = jiffies; 984 peer->rate_tokens += now - peer->rate_last; 985 if (peer->rate_tokens > ip_rt_error_burst) 986 peer->rate_tokens = ip_rt_error_burst; 987 peer->rate_last = now; 988 if (peer->rate_tokens >= ip_rt_error_cost) 989 peer->rate_tokens -= ip_rt_error_cost; 990 else 991 send = false; 992 inet_putpeer(peer); 993 } 994 if (send) 995 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 996 997 out: kfree_skb(skb); 998 return 0; 999 } 1000 1001 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1002 { 1003 struct dst_entry *dst = &rt->dst; 1004 struct fib_result res; 1005 bool lock = false; 1006 1007 if (ip_mtu_locked(dst)) 1008 return; 1009 1010 if (ipv4_mtu(dst) < mtu) 1011 return; 1012 1013 if (mtu < ip_rt_min_pmtu) { 1014 lock = true; 1015 mtu = ip_rt_min_pmtu; 1016 } 1017 1018 if (rt->rt_pmtu == mtu && 1019 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1020 return; 1021 1022 rcu_read_lock(); 1023 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1024 struct fib_nh *nh = &FIB_RES_NH(res); 1025 1026 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock, 1027 jiffies + ip_rt_mtu_expires); 1028 } 1029 rcu_read_unlock(); 1030 } 1031 1032 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1033 struct sk_buff *skb, u32 mtu) 1034 { 1035 struct rtable *rt = (struct rtable *) dst; 1036 struct flowi4 fl4; 1037 1038 ip_rt_build_flow_key(&fl4, sk, skb); 1039 __ip_rt_update_pmtu(rt, &fl4, mtu); 1040 } 1041 1042 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1043 int oif, u32 mark, u8 protocol, int flow_flags) 1044 { 1045 const struct iphdr *iph = (const struct iphdr *) skb->data; 1046 struct flowi4 fl4; 1047 struct rtable *rt; 1048 1049 if (!mark) 1050 mark = IP4_REPLY_MARK(net, skb->mark); 1051 1052 __build_flow_key(net, &fl4, NULL, iph, oif, 1053 RT_TOS(iph->tos), protocol, mark, flow_flags); 1054 rt = __ip_route_output_key(net, &fl4); 1055 if (!IS_ERR(rt)) { 1056 __ip_rt_update_pmtu(rt, &fl4, mtu); 1057 ip_rt_put(rt); 1058 } 1059 } 1060 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1061 1062 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1063 { 1064 const struct iphdr *iph = (const struct iphdr *) skb->data; 1065 struct flowi4 fl4; 1066 struct rtable *rt; 1067 1068 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1069 1070 if (!fl4.flowi4_mark) 1071 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1072 1073 rt = __ip_route_output_key(sock_net(sk), &fl4); 1074 if (!IS_ERR(rt)) { 1075 __ip_rt_update_pmtu(rt, &fl4, mtu); 1076 ip_rt_put(rt); 1077 } 1078 } 1079 1080 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1081 { 1082 const struct iphdr *iph = (const struct iphdr *) skb->data; 1083 struct flowi4 fl4; 1084 struct rtable *rt; 1085 struct dst_entry *odst = NULL; 1086 bool new = false; 1087 struct net *net = sock_net(sk); 1088 1089 bh_lock_sock(sk); 1090 1091 if (!ip_sk_accept_pmtu(sk)) 1092 goto out; 1093 1094 odst = sk_dst_get(sk); 1095 1096 if (sock_owned_by_user(sk) || !odst) { 1097 __ipv4_sk_update_pmtu(skb, sk, mtu); 1098 goto out; 1099 } 1100 1101 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1102 1103 rt = (struct rtable *)odst; 1104 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1105 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1106 if (IS_ERR(rt)) 1107 goto out; 1108 1109 new = true; 1110 } 1111 1112 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1113 1114 if (!dst_check(&rt->dst, 0)) { 1115 if (new) 1116 dst_release(&rt->dst); 1117 1118 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1119 if (IS_ERR(rt)) 1120 goto out; 1121 1122 new = true; 1123 } 1124 1125 if (new) 1126 sk_dst_set(sk, &rt->dst); 1127 1128 out: 1129 bh_unlock_sock(sk); 1130 dst_release(odst); 1131 } 1132 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1133 1134 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1135 int oif, u32 mark, u8 protocol, int flow_flags) 1136 { 1137 const struct iphdr *iph = (const struct iphdr *) skb->data; 1138 struct flowi4 fl4; 1139 struct rtable *rt; 1140 1141 __build_flow_key(net, &fl4, NULL, iph, oif, 1142 RT_TOS(iph->tos), protocol, mark, flow_flags); 1143 rt = __ip_route_output_key(net, &fl4); 1144 if (!IS_ERR(rt)) { 1145 __ip_do_redirect(rt, skb, &fl4, false); 1146 ip_rt_put(rt); 1147 } 1148 } 1149 EXPORT_SYMBOL_GPL(ipv4_redirect); 1150 1151 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1152 { 1153 const struct iphdr *iph = (const struct iphdr *) skb->data; 1154 struct flowi4 fl4; 1155 struct rtable *rt; 1156 struct net *net = sock_net(sk); 1157 1158 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1159 rt = __ip_route_output_key(net, &fl4); 1160 if (!IS_ERR(rt)) { 1161 __ip_do_redirect(rt, skb, &fl4, false); 1162 ip_rt_put(rt); 1163 } 1164 } 1165 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1166 1167 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1168 { 1169 struct rtable *rt = (struct rtable *) dst; 1170 1171 /* All IPV4 dsts are created with ->obsolete set to the value 1172 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1173 * into this function always. 1174 * 1175 * When a PMTU/redirect information update invalidates a route, 1176 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1177 * DST_OBSOLETE_DEAD by dst_free(). 1178 */ 1179 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1180 return NULL; 1181 return dst; 1182 } 1183 1184 static void ipv4_link_failure(struct sk_buff *skb) 1185 { 1186 struct rtable *rt; 1187 1188 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1189 1190 rt = skb_rtable(skb); 1191 if (rt) 1192 dst_set_expires(&rt->dst, 0); 1193 } 1194 1195 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1196 { 1197 pr_debug("%s: %pI4 -> %pI4, %s\n", 1198 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1199 skb->dev ? skb->dev->name : "?"); 1200 kfree_skb(skb); 1201 WARN_ON(1); 1202 return 0; 1203 } 1204 1205 /* 1206 We do not cache source address of outgoing interface, 1207 because it is used only by IP RR, TS and SRR options, 1208 so that it out of fast path. 1209 1210 BTW remember: "addr" is allowed to be not aligned 1211 in IP options! 1212 */ 1213 1214 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1215 { 1216 __be32 src; 1217 1218 if (rt_is_output_route(rt)) 1219 src = ip_hdr(skb)->saddr; 1220 else { 1221 struct fib_result res; 1222 struct flowi4 fl4; 1223 struct iphdr *iph; 1224 1225 iph = ip_hdr(skb); 1226 1227 memset(&fl4, 0, sizeof(fl4)); 1228 fl4.daddr = iph->daddr; 1229 fl4.saddr = iph->saddr; 1230 fl4.flowi4_tos = RT_TOS(iph->tos); 1231 fl4.flowi4_oif = rt->dst.dev->ifindex; 1232 fl4.flowi4_iif = skb->dev->ifindex; 1233 fl4.flowi4_mark = skb->mark; 1234 1235 rcu_read_lock(); 1236 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1237 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1238 else 1239 src = inet_select_addr(rt->dst.dev, 1240 rt_nexthop(rt, iph->daddr), 1241 RT_SCOPE_UNIVERSE); 1242 rcu_read_unlock(); 1243 } 1244 memcpy(addr, &src, 4); 1245 } 1246 1247 #ifdef CONFIG_IP_ROUTE_CLASSID 1248 static void set_class_tag(struct rtable *rt, u32 tag) 1249 { 1250 if (!(rt->dst.tclassid & 0xFFFF)) 1251 rt->dst.tclassid |= tag & 0xFFFF; 1252 if (!(rt->dst.tclassid & 0xFFFF0000)) 1253 rt->dst.tclassid |= tag & 0xFFFF0000; 1254 } 1255 #endif 1256 1257 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1258 { 1259 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1260 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1261 ip_rt_min_advmss); 1262 1263 return min(advmss, IPV4_MAX_PMTU - header_size); 1264 } 1265 1266 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1267 { 1268 const struct rtable *rt = (const struct rtable *) dst; 1269 unsigned int mtu = rt->rt_pmtu; 1270 1271 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1272 mtu = dst_metric_raw(dst, RTAX_MTU); 1273 1274 if (mtu) 1275 return mtu; 1276 1277 mtu = READ_ONCE(dst->dev->mtu); 1278 1279 if (unlikely(ip_mtu_locked(dst))) { 1280 if (rt->rt_uses_gateway && mtu > 576) 1281 mtu = 576; 1282 } 1283 1284 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1285 1286 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1287 } 1288 1289 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1290 { 1291 struct fnhe_hash_bucket *hash; 1292 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1293 u32 hval = fnhe_hashfun(daddr); 1294 1295 spin_lock_bh(&fnhe_lock); 1296 1297 hash = rcu_dereference_protected(nh->nh_exceptions, 1298 lockdep_is_held(&fnhe_lock)); 1299 hash += hval; 1300 1301 fnhe_p = &hash->chain; 1302 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1303 while (fnhe) { 1304 if (fnhe->fnhe_daddr == daddr) { 1305 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1306 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1307 fnhe_flush_routes(fnhe); 1308 kfree_rcu(fnhe, rcu); 1309 break; 1310 } 1311 fnhe_p = &fnhe->fnhe_next; 1312 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1313 lockdep_is_held(&fnhe_lock)); 1314 } 1315 1316 spin_unlock_bh(&fnhe_lock); 1317 } 1318 1319 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1320 { 1321 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1322 struct fib_nh_exception *fnhe; 1323 u32 hval; 1324 1325 if (!hash) 1326 return NULL; 1327 1328 hval = fnhe_hashfun(daddr); 1329 1330 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1331 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1332 if (fnhe->fnhe_daddr == daddr) { 1333 if (fnhe->fnhe_expires && 1334 time_after(jiffies, fnhe->fnhe_expires)) { 1335 ip_del_fnhe(nh, daddr); 1336 break; 1337 } 1338 return fnhe; 1339 } 1340 } 1341 return NULL; 1342 } 1343 1344 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1345 __be32 daddr, const bool do_cache) 1346 { 1347 bool ret = false; 1348 1349 spin_lock_bh(&fnhe_lock); 1350 1351 if (daddr == fnhe->fnhe_daddr) { 1352 struct rtable __rcu **porig; 1353 struct rtable *orig; 1354 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1355 1356 if (rt_is_input_route(rt)) 1357 porig = &fnhe->fnhe_rth_input; 1358 else 1359 porig = &fnhe->fnhe_rth_output; 1360 orig = rcu_dereference(*porig); 1361 1362 if (fnhe->fnhe_genid != genid) { 1363 fnhe->fnhe_genid = genid; 1364 fnhe->fnhe_gw = 0; 1365 fnhe->fnhe_pmtu = 0; 1366 fnhe->fnhe_expires = 0; 1367 fnhe->fnhe_mtu_locked = false; 1368 fnhe_flush_routes(fnhe); 1369 orig = NULL; 1370 } 1371 fill_route_from_fnhe(rt, fnhe); 1372 if (!rt->rt_gateway) 1373 rt->rt_gateway = daddr; 1374 1375 if (do_cache) { 1376 dst_hold(&rt->dst); 1377 rcu_assign_pointer(*porig, rt); 1378 if (orig) { 1379 dst_dev_put(&orig->dst); 1380 dst_release(&orig->dst); 1381 } 1382 ret = true; 1383 } 1384 1385 fnhe->fnhe_stamp = jiffies; 1386 } 1387 spin_unlock_bh(&fnhe_lock); 1388 1389 return ret; 1390 } 1391 1392 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1393 { 1394 struct rtable *orig, *prev, **p; 1395 bool ret = true; 1396 1397 if (rt_is_input_route(rt)) { 1398 p = (struct rtable **)&nh->nh_rth_input; 1399 } else { 1400 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1401 } 1402 orig = *p; 1403 1404 /* hold dst before doing cmpxchg() to avoid race condition 1405 * on this dst 1406 */ 1407 dst_hold(&rt->dst); 1408 prev = cmpxchg(p, orig, rt); 1409 if (prev == orig) { 1410 if (orig) { 1411 dst_dev_put(&orig->dst); 1412 dst_release(&orig->dst); 1413 } 1414 } else { 1415 dst_release(&rt->dst); 1416 ret = false; 1417 } 1418 1419 return ret; 1420 } 1421 1422 struct uncached_list { 1423 spinlock_t lock; 1424 struct list_head head; 1425 }; 1426 1427 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1428 1429 void rt_add_uncached_list(struct rtable *rt) 1430 { 1431 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1432 1433 rt->rt_uncached_list = ul; 1434 1435 spin_lock_bh(&ul->lock); 1436 list_add_tail(&rt->rt_uncached, &ul->head); 1437 spin_unlock_bh(&ul->lock); 1438 } 1439 1440 void rt_del_uncached_list(struct rtable *rt) 1441 { 1442 if (!list_empty(&rt->rt_uncached)) { 1443 struct uncached_list *ul = rt->rt_uncached_list; 1444 1445 spin_lock_bh(&ul->lock); 1446 list_del(&rt->rt_uncached); 1447 spin_unlock_bh(&ul->lock); 1448 } 1449 } 1450 1451 static void ipv4_dst_destroy(struct dst_entry *dst) 1452 { 1453 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst); 1454 struct rtable *rt = (struct rtable *)dst; 1455 1456 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt)) 1457 kfree(p); 1458 1459 rt_del_uncached_list(rt); 1460 } 1461 1462 void rt_flush_dev(struct net_device *dev) 1463 { 1464 struct net *net = dev_net(dev); 1465 struct rtable *rt; 1466 int cpu; 1467 1468 for_each_possible_cpu(cpu) { 1469 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1470 1471 spin_lock_bh(&ul->lock); 1472 list_for_each_entry(rt, &ul->head, rt_uncached) { 1473 if (rt->dst.dev != dev) 1474 continue; 1475 rt->dst.dev = net->loopback_dev; 1476 dev_hold(rt->dst.dev); 1477 dev_put(dev); 1478 } 1479 spin_unlock_bh(&ul->lock); 1480 } 1481 } 1482 1483 static bool rt_cache_valid(const struct rtable *rt) 1484 { 1485 return rt && 1486 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1487 !rt_is_expired(rt); 1488 } 1489 1490 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1491 const struct fib_result *res, 1492 struct fib_nh_exception *fnhe, 1493 struct fib_info *fi, u16 type, u32 itag, 1494 const bool do_cache) 1495 { 1496 bool cached = false; 1497 1498 if (fi) { 1499 struct fib_nh *nh = &FIB_RES_NH(*res); 1500 1501 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1502 rt->rt_gateway = nh->nh_gw; 1503 rt->rt_uses_gateway = 1; 1504 } 1505 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true); 1506 if (fi->fib_metrics != &dst_default_metrics) { 1507 rt->dst._metrics |= DST_METRICS_REFCOUNTED; 1508 refcount_inc(&fi->fib_metrics->refcnt); 1509 } 1510 #ifdef CONFIG_IP_ROUTE_CLASSID 1511 rt->dst.tclassid = nh->nh_tclassid; 1512 #endif 1513 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1514 if (unlikely(fnhe)) 1515 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1516 else if (do_cache) 1517 cached = rt_cache_route(nh, rt); 1518 if (unlikely(!cached)) { 1519 /* Routes we intend to cache in nexthop exception or 1520 * FIB nexthop have the DST_NOCACHE bit clear. 1521 * However, if we are unsuccessful at storing this 1522 * route into the cache we really need to set it. 1523 */ 1524 if (!rt->rt_gateway) 1525 rt->rt_gateway = daddr; 1526 rt_add_uncached_list(rt); 1527 } 1528 } else 1529 rt_add_uncached_list(rt); 1530 1531 #ifdef CONFIG_IP_ROUTE_CLASSID 1532 #ifdef CONFIG_IP_MULTIPLE_TABLES 1533 set_class_tag(rt, res->tclassid); 1534 #endif 1535 set_class_tag(rt, itag); 1536 #endif 1537 } 1538 1539 struct rtable *rt_dst_alloc(struct net_device *dev, 1540 unsigned int flags, u16 type, 1541 bool nopolicy, bool noxfrm, bool will_cache) 1542 { 1543 struct rtable *rt; 1544 1545 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1546 (will_cache ? 0 : DST_HOST) | 1547 (nopolicy ? DST_NOPOLICY : 0) | 1548 (noxfrm ? DST_NOXFRM : 0)); 1549 1550 if (rt) { 1551 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1552 rt->rt_flags = flags; 1553 rt->rt_type = type; 1554 rt->rt_is_input = 0; 1555 rt->rt_iif = 0; 1556 rt->rt_pmtu = 0; 1557 rt->rt_mtu_locked = 0; 1558 rt->rt_gateway = 0; 1559 rt->rt_uses_gateway = 0; 1560 INIT_LIST_HEAD(&rt->rt_uncached); 1561 1562 rt->dst.output = ip_output; 1563 if (flags & RTCF_LOCAL) 1564 rt->dst.input = ip_local_deliver; 1565 } 1566 1567 return rt; 1568 } 1569 EXPORT_SYMBOL(rt_dst_alloc); 1570 1571 /* called in rcu_read_lock() section */ 1572 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1573 u8 tos, struct net_device *dev, 1574 struct in_device *in_dev, u32 *itag) 1575 { 1576 int err; 1577 1578 /* Primary sanity checks. */ 1579 if (!in_dev) 1580 return -EINVAL; 1581 1582 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1583 skb->protocol != htons(ETH_P_IP)) 1584 return -EINVAL; 1585 1586 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1587 return -EINVAL; 1588 1589 if (ipv4_is_zeronet(saddr)) { 1590 if (!ipv4_is_local_multicast(daddr)) 1591 return -EINVAL; 1592 } else { 1593 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1594 in_dev, itag); 1595 if (err < 0) 1596 return err; 1597 } 1598 return 0; 1599 } 1600 1601 /* called in rcu_read_lock() section */ 1602 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1603 u8 tos, struct net_device *dev, int our) 1604 { 1605 struct in_device *in_dev = __in_dev_get_rcu(dev); 1606 unsigned int flags = RTCF_MULTICAST; 1607 struct rtable *rth; 1608 u32 itag = 0; 1609 int err; 1610 1611 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1612 if (err) 1613 return err; 1614 1615 if (our) 1616 flags |= RTCF_LOCAL; 1617 1618 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1619 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1620 if (!rth) 1621 return -ENOBUFS; 1622 1623 #ifdef CONFIG_IP_ROUTE_CLASSID 1624 rth->dst.tclassid = itag; 1625 #endif 1626 rth->dst.output = ip_rt_bug; 1627 rth->rt_is_input= 1; 1628 1629 #ifdef CONFIG_IP_MROUTE 1630 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1631 rth->dst.input = ip_mr_input; 1632 #endif 1633 RT_CACHE_STAT_INC(in_slow_mc); 1634 1635 skb_dst_set(skb, &rth->dst); 1636 return 0; 1637 } 1638 1639 1640 static void ip_handle_martian_source(struct net_device *dev, 1641 struct in_device *in_dev, 1642 struct sk_buff *skb, 1643 __be32 daddr, 1644 __be32 saddr) 1645 { 1646 RT_CACHE_STAT_INC(in_martian_src); 1647 #ifdef CONFIG_IP_ROUTE_VERBOSE 1648 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1649 /* 1650 * RFC1812 recommendation, if source is martian, 1651 * the only hint is MAC header. 1652 */ 1653 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1654 &daddr, &saddr, dev->name); 1655 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1656 print_hex_dump(KERN_WARNING, "ll header: ", 1657 DUMP_PREFIX_OFFSET, 16, 1, 1658 skb_mac_header(skb), 1659 dev->hard_header_len, true); 1660 } 1661 } 1662 #endif 1663 } 1664 1665 /* called in rcu_read_lock() section */ 1666 static int __mkroute_input(struct sk_buff *skb, 1667 const struct fib_result *res, 1668 struct in_device *in_dev, 1669 __be32 daddr, __be32 saddr, u32 tos) 1670 { 1671 struct fib_nh_exception *fnhe; 1672 struct rtable *rth; 1673 int err; 1674 struct in_device *out_dev; 1675 bool do_cache; 1676 u32 itag = 0; 1677 1678 /* get a working reference to the output device */ 1679 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1680 if (!out_dev) { 1681 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1682 return -EINVAL; 1683 } 1684 1685 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1686 in_dev->dev, in_dev, &itag); 1687 if (err < 0) { 1688 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1689 saddr); 1690 1691 goto cleanup; 1692 } 1693 1694 do_cache = res->fi && !itag; 1695 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1696 skb->protocol == htons(ETH_P_IP) && 1697 (IN_DEV_SHARED_MEDIA(out_dev) || 1698 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1699 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1700 1701 if (skb->protocol != htons(ETH_P_IP)) { 1702 /* Not IP (i.e. ARP). Do not create route, if it is 1703 * invalid for proxy arp. DNAT routes are always valid. 1704 * 1705 * Proxy arp feature have been extended to allow, ARP 1706 * replies back to the same interface, to support 1707 * Private VLAN switch technologies. See arp.c. 1708 */ 1709 if (out_dev == in_dev && 1710 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1711 err = -EINVAL; 1712 goto cleanup; 1713 } 1714 } 1715 1716 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1717 if (do_cache) { 1718 if (fnhe) 1719 rth = rcu_dereference(fnhe->fnhe_rth_input); 1720 else 1721 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1722 if (rt_cache_valid(rth)) { 1723 skb_dst_set_noref(skb, &rth->dst); 1724 goto out; 1725 } 1726 } 1727 1728 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1729 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1730 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1731 if (!rth) { 1732 err = -ENOBUFS; 1733 goto cleanup; 1734 } 1735 1736 rth->rt_is_input = 1; 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 lwtunnel_set_redirect(&rth->dst); 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 *key_iph = outer_iph; 1760 const struct iphdr *inner_iph; 1761 const struct icmphdr *icmph; 1762 struct iphdr _inner_iph; 1763 struct icmphdr _icmph; 1764 1765 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1766 goto out; 1767 1768 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1769 goto out; 1770 1771 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1772 &_icmph); 1773 if (!icmph) 1774 goto out; 1775 1776 if (icmph->type != ICMP_DEST_UNREACH && 1777 icmph->type != ICMP_REDIRECT && 1778 icmph->type != ICMP_TIME_EXCEEDED && 1779 icmph->type != ICMP_PARAMETERPROB) 1780 goto out; 1781 1782 inner_iph = skb_header_pointer(skb, 1783 outer_iph->ihl * 4 + sizeof(_icmph), 1784 sizeof(_inner_iph), &_inner_iph); 1785 if (!inner_iph) 1786 goto out; 1787 1788 key_iph = inner_iph; 1789 out: 1790 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1791 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1792 } 1793 1794 /* if skb is set it will be used and fl4 can be NULL */ 1795 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1796 const struct sk_buff *skb, struct flow_keys *flkeys) 1797 { 1798 struct flow_keys hash_keys; 1799 u32 mhash; 1800 1801 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1802 case 0: 1803 memset(&hash_keys, 0, sizeof(hash_keys)); 1804 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1805 if (skb) { 1806 ip_multipath_l3_keys(skb, &hash_keys); 1807 } else { 1808 hash_keys.addrs.v4addrs.src = fl4->saddr; 1809 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1810 } 1811 break; 1812 case 1: 1813 /* skb is currently provided only when forwarding */ 1814 if (skb) { 1815 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1816 struct flow_keys keys; 1817 1818 /* short-circuit if we already have L4 hash present */ 1819 if (skb->l4_hash) 1820 return skb_get_hash_raw(skb) >> 1; 1821 1822 memset(&hash_keys, 0, sizeof(hash_keys)); 1823 1824 if (!flkeys) { 1825 skb_flow_dissect_flow_keys(skb, &keys, flag); 1826 flkeys = &keys; 1827 } 1828 1829 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1830 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1831 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1832 hash_keys.ports.src = flkeys->ports.src; 1833 hash_keys.ports.dst = flkeys->ports.dst; 1834 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1835 } else { 1836 memset(&hash_keys, 0, sizeof(hash_keys)); 1837 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1838 hash_keys.addrs.v4addrs.src = fl4->saddr; 1839 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1840 hash_keys.ports.src = fl4->fl4_sport; 1841 hash_keys.ports.dst = fl4->fl4_dport; 1842 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1843 } 1844 break; 1845 } 1846 mhash = flow_hash_from_keys(&hash_keys); 1847 1848 return mhash >> 1; 1849 } 1850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1851 1852 static int ip_mkroute_input(struct sk_buff *skb, 1853 struct fib_result *res, 1854 struct in_device *in_dev, 1855 __be32 daddr, __be32 saddr, u32 tos, 1856 struct flow_keys *hkeys) 1857 { 1858 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1859 if (res->fi && res->fi->fib_nhs > 1) { 1860 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 1861 1862 fib_select_multipath(res, h); 1863 } 1864 #endif 1865 1866 /* create a routing cache entry */ 1867 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1868 } 1869 1870 /* 1871 * NOTE. We drop all the packets that has local source 1872 * addresses, because every properly looped back packet 1873 * must have correct destination already attached by output routine. 1874 * 1875 * Such approach solves two big problems: 1876 * 1. Not simplex devices are handled properly. 1877 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1878 * called with rcu_read_lock() 1879 */ 1880 1881 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1882 u8 tos, struct net_device *dev, 1883 struct fib_result *res) 1884 { 1885 struct in_device *in_dev = __in_dev_get_rcu(dev); 1886 struct flow_keys *flkeys = NULL, _flkeys; 1887 struct net *net = dev_net(dev); 1888 struct ip_tunnel_info *tun_info; 1889 int err = -EINVAL; 1890 unsigned int flags = 0; 1891 u32 itag = 0; 1892 struct rtable *rth; 1893 struct flowi4 fl4; 1894 bool do_cache; 1895 1896 /* IP on this device is disabled. */ 1897 1898 if (!in_dev) 1899 goto out; 1900 1901 /* Check for the most weird martians, which can be not detected 1902 by fib_lookup. 1903 */ 1904 1905 tun_info = skb_tunnel_info(skb); 1906 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1907 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1908 else 1909 fl4.flowi4_tun_key.tun_id = 0; 1910 skb_dst_drop(skb); 1911 1912 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1913 goto martian_source; 1914 1915 res->fi = NULL; 1916 res->table = NULL; 1917 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1918 goto brd_input; 1919 1920 /* Accept zero addresses only to limited broadcast; 1921 * I even do not know to fix it or not. Waiting for complains :-) 1922 */ 1923 if (ipv4_is_zeronet(saddr)) 1924 goto martian_source; 1925 1926 if (ipv4_is_zeronet(daddr)) 1927 goto martian_destination; 1928 1929 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1930 * and call it once if daddr or/and saddr are loopback addresses 1931 */ 1932 if (ipv4_is_loopback(daddr)) { 1933 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1934 goto martian_destination; 1935 } else if (ipv4_is_loopback(saddr)) { 1936 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1937 goto martian_source; 1938 } 1939 1940 /* 1941 * Now we are ready to route packet. 1942 */ 1943 fl4.flowi4_oif = 0; 1944 fl4.flowi4_iif = dev->ifindex; 1945 fl4.flowi4_mark = skb->mark; 1946 fl4.flowi4_tos = tos; 1947 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1948 fl4.flowi4_flags = 0; 1949 fl4.daddr = daddr; 1950 fl4.saddr = saddr; 1951 fl4.flowi4_uid = sock_net_uid(net, NULL); 1952 1953 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) 1954 flkeys = &_flkeys; 1955 1956 err = fib_lookup(net, &fl4, res, 0); 1957 if (err != 0) { 1958 if (!IN_DEV_FORWARD(in_dev)) 1959 err = -EHOSTUNREACH; 1960 goto no_route; 1961 } 1962 1963 if (res->type == RTN_BROADCAST) 1964 goto brd_input; 1965 1966 if (res->type == RTN_LOCAL) { 1967 err = fib_validate_source(skb, saddr, daddr, tos, 1968 0, dev, in_dev, &itag); 1969 if (err < 0) 1970 goto martian_source; 1971 goto local_input; 1972 } 1973 1974 if (!IN_DEV_FORWARD(in_dev)) { 1975 err = -EHOSTUNREACH; 1976 goto no_route; 1977 } 1978 if (res->type != RTN_UNICAST) 1979 goto martian_destination; 1980 1981 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 1982 out: return err; 1983 1984 brd_input: 1985 if (skb->protocol != htons(ETH_P_IP)) 1986 goto e_inval; 1987 1988 if (!ipv4_is_zeronet(saddr)) { 1989 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1990 in_dev, &itag); 1991 if (err < 0) 1992 goto martian_source; 1993 } 1994 flags |= RTCF_BROADCAST; 1995 res->type = RTN_BROADCAST; 1996 RT_CACHE_STAT_INC(in_brd); 1997 1998 local_input: 1999 do_cache = false; 2000 if (res->fi) { 2001 if (!itag) { 2002 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 2003 if (rt_cache_valid(rth)) { 2004 skb_dst_set_noref(skb, &rth->dst); 2005 err = 0; 2006 goto out; 2007 } 2008 do_cache = true; 2009 } 2010 } 2011 2012 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2013 flags | RTCF_LOCAL, res->type, 2014 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2015 if (!rth) 2016 goto e_nobufs; 2017 2018 rth->dst.output= ip_rt_bug; 2019 #ifdef CONFIG_IP_ROUTE_CLASSID 2020 rth->dst.tclassid = itag; 2021 #endif 2022 rth->rt_is_input = 1; 2023 2024 RT_CACHE_STAT_INC(in_slow_tot); 2025 if (res->type == RTN_UNREACHABLE) { 2026 rth->dst.input= ip_error; 2027 rth->dst.error= -err; 2028 rth->rt_flags &= ~RTCF_LOCAL; 2029 } 2030 2031 if (do_cache) { 2032 struct fib_nh *nh = &FIB_RES_NH(*res); 2033 2034 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 2035 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2036 WARN_ON(rth->dst.input == lwtunnel_input); 2037 rth->dst.lwtstate->orig_input = rth->dst.input; 2038 rth->dst.input = lwtunnel_input; 2039 } 2040 2041 if (unlikely(!rt_cache_route(nh, rth))) 2042 rt_add_uncached_list(rth); 2043 } 2044 skb_dst_set(skb, &rth->dst); 2045 err = 0; 2046 goto out; 2047 2048 no_route: 2049 RT_CACHE_STAT_INC(in_no_route); 2050 res->type = RTN_UNREACHABLE; 2051 res->fi = NULL; 2052 res->table = NULL; 2053 goto local_input; 2054 2055 /* 2056 * Do not cache martian addresses: they should be logged (RFC1812) 2057 */ 2058 martian_destination: 2059 RT_CACHE_STAT_INC(in_martian_dst); 2060 #ifdef CONFIG_IP_ROUTE_VERBOSE 2061 if (IN_DEV_LOG_MARTIANS(in_dev)) 2062 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2063 &daddr, &saddr, dev->name); 2064 #endif 2065 2066 e_inval: 2067 err = -EINVAL; 2068 goto out; 2069 2070 e_nobufs: 2071 err = -ENOBUFS; 2072 goto out; 2073 2074 martian_source: 2075 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2076 goto out; 2077 } 2078 2079 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2080 u8 tos, struct net_device *dev) 2081 { 2082 struct fib_result res; 2083 int err; 2084 2085 tos &= IPTOS_RT_MASK; 2086 rcu_read_lock(); 2087 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2088 rcu_read_unlock(); 2089 2090 return err; 2091 } 2092 EXPORT_SYMBOL(ip_route_input_noref); 2093 2094 /* called with rcu_read_lock held */ 2095 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2096 u8 tos, struct net_device *dev, struct fib_result *res) 2097 { 2098 /* Multicast recognition logic is moved from route cache to here. 2099 The problem was that too many Ethernet cards have broken/missing 2100 hardware multicast filters :-( As result the host on multicasting 2101 network acquires a lot of useless route cache entries, sort of 2102 SDR messages from all the world. Now we try to get rid of them. 2103 Really, provided software IP multicast filter is organized 2104 reasonably (at least, hashed), it does not result in a slowdown 2105 comparing with route cache reject entries. 2106 Note, that multicast routers are not affected, because 2107 route cache entry is created eventually. 2108 */ 2109 if (ipv4_is_multicast(daddr)) { 2110 struct in_device *in_dev = __in_dev_get_rcu(dev); 2111 int our = 0; 2112 int err = -EINVAL; 2113 2114 if (in_dev) 2115 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2116 ip_hdr(skb)->protocol); 2117 2118 /* check l3 master if no match yet */ 2119 if ((!in_dev || !our) && netif_is_l3_slave(dev)) { 2120 struct in_device *l3_in_dev; 2121 2122 l3_in_dev = __in_dev_get_rcu(skb->dev); 2123 if (l3_in_dev) 2124 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2125 ip_hdr(skb)->protocol); 2126 } 2127 2128 if (our 2129 #ifdef CONFIG_IP_MROUTE 2130 || 2131 (!ipv4_is_local_multicast(daddr) && 2132 IN_DEV_MFORWARD(in_dev)) 2133 #endif 2134 ) { 2135 err = ip_route_input_mc(skb, daddr, saddr, 2136 tos, dev, our); 2137 } 2138 return err; 2139 } 2140 2141 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2142 } 2143 2144 /* called with rcu_read_lock() */ 2145 static struct rtable *__mkroute_output(const struct fib_result *res, 2146 const struct flowi4 *fl4, int orig_oif, 2147 struct net_device *dev_out, 2148 unsigned int flags) 2149 { 2150 struct fib_info *fi = res->fi; 2151 struct fib_nh_exception *fnhe; 2152 struct in_device *in_dev; 2153 u16 type = res->type; 2154 struct rtable *rth; 2155 bool do_cache; 2156 2157 in_dev = __in_dev_get_rcu(dev_out); 2158 if (!in_dev) 2159 return ERR_PTR(-EINVAL); 2160 2161 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2162 if (ipv4_is_loopback(fl4->saddr) && 2163 !(dev_out->flags & IFF_LOOPBACK) && 2164 !netif_is_l3_master(dev_out)) 2165 return ERR_PTR(-EINVAL); 2166 2167 if (ipv4_is_lbcast(fl4->daddr)) 2168 type = RTN_BROADCAST; 2169 else if (ipv4_is_multicast(fl4->daddr)) 2170 type = RTN_MULTICAST; 2171 else if (ipv4_is_zeronet(fl4->daddr)) 2172 return ERR_PTR(-EINVAL); 2173 2174 if (dev_out->flags & IFF_LOOPBACK) 2175 flags |= RTCF_LOCAL; 2176 2177 do_cache = true; 2178 if (type == RTN_BROADCAST) { 2179 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2180 fi = NULL; 2181 } else if (type == RTN_MULTICAST) { 2182 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2183 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2184 fl4->flowi4_proto)) 2185 flags &= ~RTCF_LOCAL; 2186 else 2187 do_cache = false; 2188 /* If multicast route do not exist use 2189 * default one, but do not gateway in this case. 2190 * Yes, it is hack. 2191 */ 2192 if (fi && res->prefixlen < 4) 2193 fi = NULL; 2194 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2195 (orig_oif != dev_out->ifindex)) { 2196 /* For local routes that require a particular output interface 2197 * we do not want to cache the result. Caching the result 2198 * causes incorrect behaviour when there are multiple source 2199 * addresses on the interface, the end result being that if the 2200 * intended recipient is waiting on that interface for the 2201 * packet he won't receive it because it will be delivered on 2202 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2203 * be set to the loopback interface as well. 2204 */ 2205 do_cache = false; 2206 } 2207 2208 fnhe = NULL; 2209 do_cache &= fi != NULL; 2210 if (fi) { 2211 struct rtable __rcu **prth; 2212 struct fib_nh *nh = &FIB_RES_NH(*res); 2213 2214 fnhe = find_exception(nh, fl4->daddr); 2215 if (!do_cache) 2216 goto add; 2217 if (fnhe) { 2218 prth = &fnhe->fnhe_rth_output; 2219 } else { 2220 if (unlikely(fl4->flowi4_flags & 2221 FLOWI_FLAG_KNOWN_NH && 2222 !(nh->nh_gw && 2223 nh->nh_scope == RT_SCOPE_LINK))) { 2224 do_cache = false; 2225 goto add; 2226 } 2227 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2228 } 2229 rth = rcu_dereference(*prth); 2230 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2231 return rth; 2232 } 2233 2234 add: 2235 rth = rt_dst_alloc(dev_out, flags, type, 2236 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2237 IN_DEV_CONF_GET(in_dev, NOXFRM), 2238 do_cache); 2239 if (!rth) 2240 return ERR_PTR(-ENOBUFS); 2241 2242 rth->rt_iif = orig_oif; 2243 2244 RT_CACHE_STAT_INC(out_slow_tot); 2245 2246 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2247 if (flags & RTCF_LOCAL && 2248 !(dev_out->flags & IFF_LOOPBACK)) { 2249 rth->dst.output = ip_mc_output; 2250 RT_CACHE_STAT_INC(out_slow_mc); 2251 } 2252 #ifdef CONFIG_IP_MROUTE 2253 if (type == RTN_MULTICAST) { 2254 if (IN_DEV_MFORWARD(in_dev) && 2255 !ipv4_is_local_multicast(fl4->daddr)) { 2256 rth->dst.input = ip_mr_input; 2257 rth->dst.output = ip_mc_output; 2258 } 2259 } 2260 #endif 2261 } 2262 2263 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2264 lwtunnel_set_redirect(&rth->dst); 2265 2266 return rth; 2267 } 2268 2269 /* 2270 * Major route resolver routine. 2271 */ 2272 2273 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2274 const struct sk_buff *skb) 2275 { 2276 __u8 tos = RT_FL_TOS(fl4); 2277 struct fib_result res = { 2278 .type = RTN_UNSPEC, 2279 .fi = NULL, 2280 .table = NULL, 2281 .tclassid = 0, 2282 }; 2283 struct rtable *rth; 2284 2285 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2286 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2287 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2288 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2289 2290 rcu_read_lock(); 2291 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2292 rcu_read_unlock(); 2293 2294 return rth; 2295 } 2296 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2297 2298 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2299 struct fib_result *res, 2300 const struct sk_buff *skb) 2301 { 2302 struct net_device *dev_out = NULL; 2303 int orig_oif = fl4->flowi4_oif; 2304 unsigned int flags = 0; 2305 struct rtable *rth; 2306 int err = -ENETUNREACH; 2307 2308 if (fl4->saddr) { 2309 rth = ERR_PTR(-EINVAL); 2310 if (ipv4_is_multicast(fl4->saddr) || 2311 ipv4_is_lbcast(fl4->saddr) || 2312 ipv4_is_zeronet(fl4->saddr)) 2313 goto out; 2314 2315 /* I removed check for oif == dev_out->oif here. 2316 It was wrong for two reasons: 2317 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2318 is assigned to multiple interfaces. 2319 2. Moreover, we are allowed to send packets with saddr 2320 of another iface. --ANK 2321 */ 2322 2323 if (fl4->flowi4_oif == 0 && 2324 (ipv4_is_multicast(fl4->daddr) || 2325 ipv4_is_lbcast(fl4->daddr))) { 2326 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2327 dev_out = __ip_dev_find(net, fl4->saddr, false); 2328 if (!dev_out) 2329 goto out; 2330 2331 /* Special hack: user can direct multicasts 2332 and limited broadcast via necessary interface 2333 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2334 This hack is not just for fun, it allows 2335 vic,vat and friends to work. 2336 They bind socket to loopback, set ttl to zero 2337 and expect that it will work. 2338 From the viewpoint of routing cache they are broken, 2339 because we are not allowed to build multicast path 2340 with loopback source addr (look, routing cache 2341 cannot know, that ttl is zero, so that packet 2342 will not leave this host and route is valid). 2343 Luckily, this hack is good workaround. 2344 */ 2345 2346 fl4->flowi4_oif = dev_out->ifindex; 2347 goto make_route; 2348 } 2349 2350 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2351 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2352 if (!__ip_dev_find(net, fl4->saddr, false)) 2353 goto out; 2354 } 2355 } 2356 2357 2358 if (fl4->flowi4_oif) { 2359 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2360 rth = ERR_PTR(-ENODEV); 2361 if (!dev_out) 2362 goto out; 2363 2364 /* RACE: Check return value of inet_select_addr instead. */ 2365 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2366 rth = ERR_PTR(-ENETUNREACH); 2367 goto out; 2368 } 2369 if (ipv4_is_local_multicast(fl4->daddr) || 2370 ipv4_is_lbcast(fl4->daddr) || 2371 fl4->flowi4_proto == IPPROTO_IGMP) { 2372 if (!fl4->saddr) 2373 fl4->saddr = inet_select_addr(dev_out, 0, 2374 RT_SCOPE_LINK); 2375 goto make_route; 2376 } 2377 if (!fl4->saddr) { 2378 if (ipv4_is_multicast(fl4->daddr)) 2379 fl4->saddr = inet_select_addr(dev_out, 0, 2380 fl4->flowi4_scope); 2381 else if (!fl4->daddr) 2382 fl4->saddr = inet_select_addr(dev_out, 0, 2383 RT_SCOPE_HOST); 2384 } 2385 } 2386 2387 if (!fl4->daddr) { 2388 fl4->daddr = fl4->saddr; 2389 if (!fl4->daddr) 2390 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2391 dev_out = net->loopback_dev; 2392 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2393 res->type = RTN_LOCAL; 2394 flags |= RTCF_LOCAL; 2395 goto make_route; 2396 } 2397 2398 err = fib_lookup(net, fl4, res, 0); 2399 if (err) { 2400 res->fi = NULL; 2401 res->table = NULL; 2402 if (fl4->flowi4_oif && 2403 (ipv4_is_multicast(fl4->daddr) || 2404 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2405 /* Apparently, routing tables are wrong. Assume, 2406 that the destination is on link. 2407 2408 WHY? DW. 2409 Because we are allowed to send to iface 2410 even if it has NO routes and NO assigned 2411 addresses. When oif is specified, routing 2412 tables are looked up with only one purpose: 2413 to catch if destination is gatewayed, rather than 2414 direct. Moreover, if MSG_DONTROUTE is set, 2415 we send packet, ignoring both routing tables 2416 and ifaddr state. --ANK 2417 2418 2419 We could make it even if oif is unknown, 2420 likely IPv6, but we do not. 2421 */ 2422 2423 if (fl4->saddr == 0) 2424 fl4->saddr = inet_select_addr(dev_out, 0, 2425 RT_SCOPE_LINK); 2426 res->type = RTN_UNICAST; 2427 goto make_route; 2428 } 2429 rth = ERR_PTR(err); 2430 goto out; 2431 } 2432 2433 if (res->type == RTN_LOCAL) { 2434 if (!fl4->saddr) { 2435 if (res->fi->fib_prefsrc) 2436 fl4->saddr = res->fi->fib_prefsrc; 2437 else 2438 fl4->saddr = fl4->daddr; 2439 } 2440 2441 /* L3 master device is the loopback for that domain */ 2442 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2443 net->loopback_dev; 2444 2445 /* make sure orig_oif points to fib result device even 2446 * though packet rx/tx happens over loopback or l3mdev 2447 */ 2448 orig_oif = FIB_RES_OIF(*res); 2449 2450 fl4->flowi4_oif = dev_out->ifindex; 2451 flags |= RTCF_LOCAL; 2452 goto make_route; 2453 } 2454 2455 fib_select_path(net, res, fl4, skb); 2456 2457 dev_out = FIB_RES_DEV(*res); 2458 fl4->flowi4_oif = dev_out->ifindex; 2459 2460 2461 make_route: 2462 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2463 2464 out: 2465 return rth; 2466 } 2467 2468 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2469 { 2470 return NULL; 2471 } 2472 2473 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2474 { 2475 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2476 2477 return mtu ? : dst->dev->mtu; 2478 } 2479 2480 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2481 struct sk_buff *skb, u32 mtu) 2482 { 2483 } 2484 2485 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2486 struct sk_buff *skb) 2487 { 2488 } 2489 2490 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2491 unsigned long old) 2492 { 2493 return NULL; 2494 } 2495 2496 static struct dst_ops ipv4_dst_blackhole_ops = { 2497 .family = AF_INET, 2498 .check = ipv4_blackhole_dst_check, 2499 .mtu = ipv4_blackhole_mtu, 2500 .default_advmss = ipv4_default_advmss, 2501 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2502 .redirect = ipv4_rt_blackhole_redirect, 2503 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2504 .neigh_lookup = ipv4_neigh_lookup, 2505 }; 2506 2507 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2508 { 2509 struct rtable *ort = (struct rtable *) dst_orig; 2510 struct rtable *rt; 2511 2512 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2513 if (rt) { 2514 struct dst_entry *new = &rt->dst; 2515 2516 new->__use = 1; 2517 new->input = dst_discard; 2518 new->output = dst_discard_out; 2519 2520 new->dev = net->loopback_dev; 2521 if (new->dev) 2522 dev_hold(new->dev); 2523 2524 rt->rt_is_input = ort->rt_is_input; 2525 rt->rt_iif = ort->rt_iif; 2526 rt->rt_pmtu = ort->rt_pmtu; 2527 rt->rt_mtu_locked = ort->rt_mtu_locked; 2528 2529 rt->rt_genid = rt_genid_ipv4(net); 2530 rt->rt_flags = ort->rt_flags; 2531 rt->rt_type = ort->rt_type; 2532 rt->rt_gateway = ort->rt_gateway; 2533 rt->rt_uses_gateway = ort->rt_uses_gateway; 2534 2535 INIT_LIST_HEAD(&rt->rt_uncached); 2536 } 2537 2538 dst_release(dst_orig); 2539 2540 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2541 } 2542 2543 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2544 const struct sock *sk) 2545 { 2546 struct rtable *rt = __ip_route_output_key(net, flp4); 2547 2548 if (IS_ERR(rt)) 2549 return rt; 2550 2551 if (flp4->flowi4_proto) 2552 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2553 flowi4_to_flowi(flp4), 2554 sk, 0); 2555 2556 return rt; 2557 } 2558 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2559 2560 /* called with rcu_read_lock held */ 2561 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2562 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2563 u32 seq) 2564 { 2565 struct rtable *rt = skb_rtable(skb); 2566 struct rtmsg *r; 2567 struct nlmsghdr *nlh; 2568 unsigned long expires = 0; 2569 u32 error; 2570 u32 metrics[RTAX_MAX]; 2571 2572 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0); 2573 if (!nlh) 2574 return -EMSGSIZE; 2575 2576 r = nlmsg_data(nlh); 2577 r->rtm_family = AF_INET; 2578 r->rtm_dst_len = 32; 2579 r->rtm_src_len = 0; 2580 r->rtm_tos = fl4->flowi4_tos; 2581 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2582 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2583 goto nla_put_failure; 2584 r->rtm_type = rt->rt_type; 2585 r->rtm_scope = RT_SCOPE_UNIVERSE; 2586 r->rtm_protocol = RTPROT_UNSPEC; 2587 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2588 if (rt->rt_flags & RTCF_NOTIFY) 2589 r->rtm_flags |= RTM_F_NOTIFY; 2590 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2591 r->rtm_flags |= RTCF_DOREDIRECT; 2592 2593 if (nla_put_in_addr(skb, RTA_DST, dst)) 2594 goto nla_put_failure; 2595 if (src) { 2596 r->rtm_src_len = 32; 2597 if (nla_put_in_addr(skb, RTA_SRC, src)) 2598 goto nla_put_failure; 2599 } 2600 if (rt->dst.dev && 2601 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2602 goto nla_put_failure; 2603 #ifdef CONFIG_IP_ROUTE_CLASSID 2604 if (rt->dst.tclassid && 2605 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2606 goto nla_put_failure; 2607 #endif 2608 if (!rt_is_input_route(rt) && 2609 fl4->saddr != src) { 2610 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2611 goto nla_put_failure; 2612 } 2613 if (rt->rt_uses_gateway && 2614 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2615 goto nla_put_failure; 2616 2617 expires = rt->dst.expires; 2618 if (expires) { 2619 unsigned long now = jiffies; 2620 2621 if (time_before(now, expires)) 2622 expires -= now; 2623 else 2624 expires = 0; 2625 } 2626 2627 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2628 if (rt->rt_pmtu && expires) 2629 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2630 if (rt->rt_mtu_locked && expires) 2631 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2632 if (rtnetlink_put_metrics(skb, metrics) < 0) 2633 goto nla_put_failure; 2634 2635 if (fl4->flowi4_mark && 2636 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2637 goto nla_put_failure; 2638 2639 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2640 nla_put_u32(skb, RTA_UID, 2641 from_kuid_munged(current_user_ns(), fl4->flowi4_uid))) 2642 goto nla_put_failure; 2643 2644 error = rt->dst.error; 2645 2646 if (rt_is_input_route(rt)) { 2647 #ifdef CONFIG_IP_MROUTE 2648 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2649 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2650 int err = ipmr_get_route(net, skb, 2651 fl4->saddr, fl4->daddr, 2652 r, portid); 2653 2654 if (err <= 0) { 2655 if (err == 0) 2656 return 0; 2657 goto nla_put_failure; 2658 } 2659 } else 2660 #endif 2661 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2662 goto nla_put_failure; 2663 } 2664 2665 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2666 goto nla_put_failure; 2667 2668 nlmsg_end(skb, nlh); 2669 return 0; 2670 2671 nla_put_failure: 2672 nlmsg_cancel(skb, nlh); 2673 return -EMSGSIZE; 2674 } 2675 2676 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 2677 struct netlink_ext_ack *extack) 2678 { 2679 struct net *net = sock_net(in_skb->sk); 2680 struct rtmsg *rtm; 2681 struct nlattr *tb[RTA_MAX+1]; 2682 struct fib_result res = {}; 2683 struct rtable *rt = NULL; 2684 struct flowi4 fl4; 2685 __be32 dst = 0; 2686 __be32 src = 0; 2687 u32 iif; 2688 int err; 2689 int mark; 2690 struct sk_buff *skb; 2691 u32 table_id = RT_TABLE_MAIN; 2692 kuid_t uid; 2693 2694 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy, 2695 extack); 2696 if (err < 0) 2697 goto errout; 2698 2699 rtm = nlmsg_data(nlh); 2700 2701 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2702 if (!skb) { 2703 err = -ENOBUFS; 2704 goto errout; 2705 } 2706 2707 /* Reserve room for dummy headers, this skb can pass 2708 through good chunk of routing engine. 2709 */ 2710 skb_reset_mac_header(skb); 2711 skb_reset_network_header(skb); 2712 2713 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2714 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2715 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2716 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2717 if (tb[RTA_UID]) 2718 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 2719 else 2720 uid = (iif ? INVALID_UID : current_uid()); 2721 2722 /* Bugfix: need to give ip_route_input enough of an IP header to 2723 * not gag. 2724 */ 2725 ip_hdr(skb)->protocol = IPPROTO_UDP; 2726 ip_hdr(skb)->saddr = src; 2727 ip_hdr(skb)->daddr = dst; 2728 2729 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2730 2731 memset(&fl4, 0, sizeof(fl4)); 2732 fl4.daddr = dst; 2733 fl4.saddr = src; 2734 fl4.flowi4_tos = rtm->rtm_tos; 2735 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2736 fl4.flowi4_mark = mark; 2737 fl4.flowi4_uid = uid; 2738 2739 rcu_read_lock(); 2740 2741 if (iif) { 2742 struct net_device *dev; 2743 2744 dev = dev_get_by_index_rcu(net, iif); 2745 if (!dev) { 2746 err = -ENODEV; 2747 goto errout_free; 2748 } 2749 2750 skb->protocol = htons(ETH_P_IP); 2751 skb->dev = dev; 2752 skb->mark = mark; 2753 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 2754 dev, &res); 2755 2756 rt = skb_rtable(skb); 2757 if (err == 0 && rt->dst.error) 2758 err = -rt->dst.error; 2759 } else { 2760 fl4.flowi4_iif = LOOPBACK_IFINDEX; 2761 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 2762 err = 0; 2763 if (IS_ERR(rt)) 2764 err = PTR_ERR(rt); 2765 else 2766 skb_dst_set(skb, &rt->dst); 2767 } 2768 2769 if (err) 2770 goto errout_free; 2771 2772 if (rtm->rtm_flags & RTM_F_NOTIFY) 2773 rt->rt_flags |= RTCF_NOTIFY; 2774 2775 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2776 table_id = res.table ? res.table->tb_id : 0; 2777 2778 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 2779 if (!res.fi) { 2780 err = fib_props[res.type].error; 2781 if (!err) 2782 err = -EHOSTUNREACH; 2783 goto errout_free; 2784 } 2785 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 2786 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 2787 rt->rt_type, res.prefix, res.prefixlen, 2788 fl4.flowi4_tos, res.fi, 0); 2789 } else { 2790 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2791 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq); 2792 } 2793 if (err < 0) 2794 goto errout_free; 2795 2796 rcu_read_unlock(); 2797 2798 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2799 errout: 2800 return err; 2801 2802 errout_free: 2803 rcu_read_unlock(); 2804 kfree_skb(skb); 2805 goto errout; 2806 } 2807 2808 void ip_rt_multicast_event(struct in_device *in_dev) 2809 { 2810 rt_cache_flush(dev_net(in_dev->dev)); 2811 } 2812 2813 #ifdef CONFIG_SYSCTL 2814 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2815 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2816 static int ip_rt_gc_elasticity __read_mostly = 8; 2817 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 2818 2819 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2820 void __user *buffer, 2821 size_t *lenp, loff_t *ppos) 2822 { 2823 struct net *net = (struct net *)__ctl->extra1; 2824 2825 if (write) { 2826 rt_cache_flush(net); 2827 fnhe_genid_bump(net); 2828 return 0; 2829 } 2830 2831 return -EINVAL; 2832 } 2833 2834 static struct ctl_table ipv4_route_table[] = { 2835 { 2836 .procname = "gc_thresh", 2837 .data = &ipv4_dst_ops.gc_thresh, 2838 .maxlen = sizeof(int), 2839 .mode = 0644, 2840 .proc_handler = proc_dointvec, 2841 }, 2842 { 2843 .procname = "max_size", 2844 .data = &ip_rt_max_size, 2845 .maxlen = sizeof(int), 2846 .mode = 0644, 2847 .proc_handler = proc_dointvec, 2848 }, 2849 { 2850 /* Deprecated. Use gc_min_interval_ms */ 2851 2852 .procname = "gc_min_interval", 2853 .data = &ip_rt_gc_min_interval, 2854 .maxlen = sizeof(int), 2855 .mode = 0644, 2856 .proc_handler = proc_dointvec_jiffies, 2857 }, 2858 { 2859 .procname = "gc_min_interval_ms", 2860 .data = &ip_rt_gc_min_interval, 2861 .maxlen = sizeof(int), 2862 .mode = 0644, 2863 .proc_handler = proc_dointvec_ms_jiffies, 2864 }, 2865 { 2866 .procname = "gc_timeout", 2867 .data = &ip_rt_gc_timeout, 2868 .maxlen = sizeof(int), 2869 .mode = 0644, 2870 .proc_handler = proc_dointvec_jiffies, 2871 }, 2872 { 2873 .procname = "gc_interval", 2874 .data = &ip_rt_gc_interval, 2875 .maxlen = sizeof(int), 2876 .mode = 0644, 2877 .proc_handler = proc_dointvec_jiffies, 2878 }, 2879 { 2880 .procname = "redirect_load", 2881 .data = &ip_rt_redirect_load, 2882 .maxlen = sizeof(int), 2883 .mode = 0644, 2884 .proc_handler = proc_dointvec, 2885 }, 2886 { 2887 .procname = "redirect_number", 2888 .data = &ip_rt_redirect_number, 2889 .maxlen = sizeof(int), 2890 .mode = 0644, 2891 .proc_handler = proc_dointvec, 2892 }, 2893 { 2894 .procname = "redirect_silence", 2895 .data = &ip_rt_redirect_silence, 2896 .maxlen = sizeof(int), 2897 .mode = 0644, 2898 .proc_handler = proc_dointvec, 2899 }, 2900 { 2901 .procname = "error_cost", 2902 .data = &ip_rt_error_cost, 2903 .maxlen = sizeof(int), 2904 .mode = 0644, 2905 .proc_handler = proc_dointvec, 2906 }, 2907 { 2908 .procname = "error_burst", 2909 .data = &ip_rt_error_burst, 2910 .maxlen = sizeof(int), 2911 .mode = 0644, 2912 .proc_handler = proc_dointvec, 2913 }, 2914 { 2915 .procname = "gc_elasticity", 2916 .data = &ip_rt_gc_elasticity, 2917 .maxlen = sizeof(int), 2918 .mode = 0644, 2919 .proc_handler = proc_dointvec, 2920 }, 2921 { 2922 .procname = "mtu_expires", 2923 .data = &ip_rt_mtu_expires, 2924 .maxlen = sizeof(int), 2925 .mode = 0644, 2926 .proc_handler = proc_dointvec_jiffies, 2927 }, 2928 { 2929 .procname = "min_pmtu", 2930 .data = &ip_rt_min_pmtu, 2931 .maxlen = sizeof(int), 2932 .mode = 0644, 2933 .proc_handler = proc_dointvec_minmax, 2934 .extra1 = &ip_min_valid_pmtu, 2935 }, 2936 { 2937 .procname = "min_adv_mss", 2938 .data = &ip_rt_min_advmss, 2939 .maxlen = sizeof(int), 2940 .mode = 0644, 2941 .proc_handler = proc_dointvec, 2942 }, 2943 { } 2944 }; 2945 2946 static struct ctl_table ipv4_route_flush_table[] = { 2947 { 2948 .procname = "flush", 2949 .maxlen = sizeof(int), 2950 .mode = 0200, 2951 .proc_handler = ipv4_sysctl_rtcache_flush, 2952 }, 2953 { }, 2954 }; 2955 2956 static __net_init int sysctl_route_net_init(struct net *net) 2957 { 2958 struct ctl_table *tbl; 2959 2960 tbl = ipv4_route_flush_table; 2961 if (!net_eq(net, &init_net)) { 2962 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2963 if (!tbl) 2964 goto err_dup; 2965 2966 /* Don't export sysctls to unprivileged users */ 2967 if (net->user_ns != &init_user_ns) 2968 tbl[0].procname = NULL; 2969 } 2970 tbl[0].extra1 = net; 2971 2972 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2973 if (!net->ipv4.route_hdr) 2974 goto err_reg; 2975 return 0; 2976 2977 err_reg: 2978 if (tbl != ipv4_route_flush_table) 2979 kfree(tbl); 2980 err_dup: 2981 return -ENOMEM; 2982 } 2983 2984 static __net_exit void sysctl_route_net_exit(struct net *net) 2985 { 2986 struct ctl_table *tbl; 2987 2988 tbl = net->ipv4.route_hdr->ctl_table_arg; 2989 unregister_net_sysctl_table(net->ipv4.route_hdr); 2990 BUG_ON(tbl == ipv4_route_flush_table); 2991 kfree(tbl); 2992 } 2993 2994 static __net_initdata struct pernet_operations sysctl_route_ops = { 2995 .init = sysctl_route_net_init, 2996 .exit = sysctl_route_net_exit, 2997 }; 2998 #endif 2999 3000 static __net_init int rt_genid_init(struct net *net) 3001 { 3002 atomic_set(&net->ipv4.rt_genid, 0); 3003 atomic_set(&net->fnhe_genid, 0); 3004 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3005 return 0; 3006 } 3007 3008 static __net_initdata struct pernet_operations rt_genid_ops = { 3009 .init = rt_genid_init, 3010 }; 3011 3012 static int __net_init ipv4_inetpeer_init(struct net *net) 3013 { 3014 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3015 3016 if (!bp) 3017 return -ENOMEM; 3018 inet_peer_base_init(bp); 3019 net->ipv4.peers = bp; 3020 return 0; 3021 } 3022 3023 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3024 { 3025 struct inet_peer_base *bp = net->ipv4.peers; 3026 3027 net->ipv4.peers = NULL; 3028 inetpeer_invalidate_tree(bp); 3029 kfree(bp); 3030 } 3031 3032 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3033 .init = ipv4_inetpeer_init, 3034 .exit = ipv4_inetpeer_exit, 3035 }; 3036 3037 #ifdef CONFIG_IP_ROUTE_CLASSID 3038 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3039 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3040 3041 int __init ip_rt_init(void) 3042 { 3043 int cpu; 3044 3045 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 3046 if (!ip_idents) 3047 panic("IP: failed to allocate ip_idents\n"); 3048 3049 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3050 3051 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3052 if (!ip_tstamps) 3053 panic("IP: failed to allocate ip_tstamps\n"); 3054 3055 for_each_possible_cpu(cpu) { 3056 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3057 3058 INIT_LIST_HEAD(&ul->head); 3059 spin_lock_init(&ul->lock); 3060 } 3061 #ifdef CONFIG_IP_ROUTE_CLASSID 3062 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3063 if (!ip_rt_acct) 3064 panic("IP: failed to allocate ip_rt_acct\n"); 3065 #endif 3066 3067 ipv4_dst_ops.kmem_cachep = 3068 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3069 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3070 3071 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3072 3073 if (dst_entries_init(&ipv4_dst_ops) < 0) 3074 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3075 3076 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3077 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3078 3079 ipv4_dst_ops.gc_thresh = ~0; 3080 ip_rt_max_size = INT_MAX; 3081 3082 devinet_init(); 3083 ip_fib_init(); 3084 3085 if (ip_rt_proc_init()) 3086 pr_err("Unable to create route proc files\n"); 3087 #ifdef CONFIG_XFRM 3088 xfrm_init(); 3089 xfrm4_init(); 3090 #endif 3091 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3092 RTNL_FLAG_DOIT_UNLOCKED); 3093 3094 #ifdef CONFIG_SYSCTL 3095 register_pernet_subsys(&sysctl_route_ops); 3096 #endif 3097 register_pernet_subsys(&rt_genid_ops); 3098 register_pernet_subsys(&ipv4_inetpeer_ops); 3099 return 0; 3100 } 3101 3102 #ifdef CONFIG_SYSCTL 3103 /* 3104 * We really need to sanitize the damn ipv4 init order, then all 3105 * this nonsense will go away. 3106 */ 3107 void __init ip_static_sysctl_init(void) 3108 { 3109 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3110 } 3111 #endif 3112