1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * ROUTE - implementation of the IP router. 8 * 9 * Authors: Ross Biro 10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * Alan Cox, <gw4pts@gw4pts.ampr.org> 12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 14 * 15 * Fixes: 16 * Alan Cox : Verify area fixes. 17 * Alan Cox : cli() protects routing changes 18 * Rui Oliveira : ICMP routing table updates 19 * (rco@di.uminho.pt) Routing table insertion and update 20 * Linus Torvalds : Rewrote bits to be sensible 21 * Alan Cox : Added BSD route gw semantics 22 * Alan Cox : Super /proc >4K 23 * Alan Cox : MTU in route table 24 * Alan Cox : MSS actually. Also added the window 25 * clamper. 26 * Sam Lantinga : Fixed route matching in rt_del() 27 * Alan Cox : Routing cache support. 28 * Alan Cox : Removed compatibility cruft. 29 * Alan Cox : RTF_REJECT support. 30 * Alan Cox : TCP irtt support. 31 * Jonathan Naylor : Added Metric support. 32 * Miquel van Smoorenburg : BSD API fixes. 33 * Miquel van Smoorenburg : Metrics. 34 * Alan Cox : Use __u32 properly 35 * Alan Cox : Aligned routing errors more closely with BSD 36 * our system is still very different. 37 * Alan Cox : Faster /proc handling 38 * Alexey Kuznetsov : Massive rework to support tree based routing, 39 * routing caches and better behaviour. 40 * 41 * Olaf Erb : irtt wasn't being copied right. 42 * Bjorn Ekwall : Kerneld route support. 43 * Alan Cox : Multicast fixed (I hope) 44 * Pavel Krauz : Limited broadcast fixed 45 * Mike McLagan : Routing by source 46 * Alexey Kuznetsov : End of old history. Split to fib.c and 47 * route.c and rewritten from scratch. 48 * Andi Kleen : Load-limit warning messages. 49 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 53 * Marc Boucher : routing by fwmark 54 * Robert Olsson : Added rt_cache statistics 55 * Arnaldo C. Melo : Convert proc stuff to seq_file 56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 58 * Ilia Sotnikov : Removed TOS from hash calculations 59 */ 60 61 #define pr_fmt(fmt) "IPv4: " fmt 62 63 #include <linux/module.h> 64 #include <linux/uaccess.h> 65 #include <linux/bitops.h> 66 #include <linux/types.h> 67 #include <linux/kernel.h> 68 #include <linux/mm.h> 69 #include <linux/memblock.h> 70 #include <linux/string.h> 71 #include <linux/socket.h> 72 #include <linux/sockios.h> 73 #include <linux/errno.h> 74 #include <linux/in.h> 75 #include <linux/inet.h> 76 #include <linux/netdevice.h> 77 #include <linux/proc_fs.h> 78 #include <linux/init.h> 79 #include <linux/skbuff.h> 80 #include <linux/inetdevice.h> 81 #include <linux/igmp.h> 82 #include <linux/pkt_sched.h> 83 #include <linux/mroute.h> 84 #include <linux/netfilter_ipv4.h> 85 #include <linux/random.h> 86 #include <linux/rcupdate.h> 87 #include <linux/times.h> 88 #include <linux/slab.h> 89 #include <linux/jhash.h> 90 #include <net/dst.h> 91 #include <net/dst_metadata.h> 92 #include <net/net_namespace.h> 93 #include <net/protocol.h> 94 #include <net/ip.h> 95 #include <net/route.h> 96 #include <net/inetpeer.h> 97 #include <net/sock.h> 98 #include <net/ip_fib.h> 99 #include <net/nexthop.h> 100 #include <net/arp.h> 101 #include <net/tcp.h> 102 #include <net/icmp.h> 103 #include <net/xfrm.h> 104 #include <net/lwtunnel.h> 105 #include <net/netevent.h> 106 #include <net/rtnetlink.h> 107 #ifdef CONFIG_SYSCTL 108 #include <linux/sysctl.h> 109 #endif 110 #include <net/secure_seq.h> 111 #include <net/ip_tunnels.h> 112 #include <net/l3mdev.h> 113 114 #include "fib_lookup.h" 115 116 #define RT_FL_TOS(oldflp4) \ 117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 118 119 #define RT_GC_TIMEOUT (300*HZ) 120 121 static int ip_rt_max_size; 122 static int ip_rt_redirect_number __read_mostly = 9; 123 static int ip_rt_redirect_load __read_mostly = HZ / 50; 124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 125 static int ip_rt_error_cost __read_mostly = HZ; 126 static int ip_rt_error_burst __read_mostly = 5 * HZ; 127 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 128 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 129 static int ip_rt_min_advmss __read_mostly = 256; 130 131 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 132 133 /* 134 * Interface to generic destination cache. 135 */ 136 137 INDIRECT_CALLABLE_SCOPE 138 struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 139 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 140 INDIRECT_CALLABLE_SCOPE 141 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 bool confirm_neigh); 147 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 148 struct sk_buff *skb); 149 static void ipv4_dst_destroy(struct dst_entry *dst); 150 151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 152 { 153 WARN_ON(1); 154 return NULL; 155 } 156 157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 158 struct sk_buff *skb, 159 const void *daddr); 160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 161 162 static struct dst_ops ipv4_dst_ops = { 163 .family = AF_INET, 164 .check = ipv4_dst_check, 165 .default_advmss = ipv4_default_advmss, 166 .mtu = ipv4_mtu, 167 .cow_metrics = ipv4_cow_metrics, 168 .destroy = ipv4_dst_destroy, 169 .negative_advice = ipv4_negative_advice, 170 .link_failure = ipv4_link_failure, 171 .update_pmtu = ip_rt_update_pmtu, 172 .redirect = ip_do_redirect, 173 .local_out = __ip_local_out, 174 .neigh_lookup = ipv4_neigh_lookup, 175 .confirm_neigh = ipv4_confirm_neigh, 176 }; 177 178 #define ECN_OR_COST(class) TC_PRIO_##class 179 180 const __u8 ip_tos2prio[16] = { 181 TC_PRIO_BESTEFFORT, 182 ECN_OR_COST(BESTEFFORT), 183 TC_PRIO_BESTEFFORT, 184 ECN_OR_COST(BESTEFFORT), 185 TC_PRIO_BULK, 186 ECN_OR_COST(BULK), 187 TC_PRIO_BULK, 188 ECN_OR_COST(BULK), 189 TC_PRIO_INTERACTIVE, 190 ECN_OR_COST(INTERACTIVE), 191 TC_PRIO_INTERACTIVE, 192 ECN_OR_COST(INTERACTIVE), 193 TC_PRIO_INTERACTIVE_BULK, 194 ECN_OR_COST(INTERACTIVE_BULK), 195 TC_PRIO_INTERACTIVE_BULK, 196 ECN_OR_COST(INTERACTIVE_BULK) 197 }; 198 EXPORT_SYMBOL(ip_tos2prio); 199 200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 202 203 #ifdef CONFIG_PROC_FS 204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 205 { 206 if (*pos) 207 return NULL; 208 return SEQ_START_TOKEN; 209 } 210 211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 212 { 213 ++*pos; 214 return NULL; 215 } 216 217 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 218 { 219 } 220 221 static int rt_cache_seq_show(struct seq_file *seq, void *v) 222 { 223 if (v == SEQ_START_TOKEN) 224 seq_printf(seq, "%-127s\n", 225 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 226 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 227 "HHUptod\tSpecDst"); 228 return 0; 229 } 230 231 static const struct seq_operations rt_cache_seq_ops = { 232 .start = rt_cache_seq_start, 233 .next = rt_cache_seq_next, 234 .stop = rt_cache_seq_stop, 235 .show = rt_cache_seq_show, 236 }; 237 238 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 239 { 240 int cpu; 241 242 if (*pos == 0) 243 return SEQ_START_TOKEN; 244 245 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 246 if (!cpu_possible(cpu)) 247 continue; 248 *pos = cpu+1; 249 return &per_cpu(rt_cache_stat, cpu); 250 } 251 return NULL; 252 } 253 254 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 255 { 256 int cpu; 257 258 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 259 if (!cpu_possible(cpu)) 260 continue; 261 *pos = cpu+1; 262 return &per_cpu(rt_cache_stat, cpu); 263 } 264 (*pos)++; 265 return NULL; 266 267 } 268 269 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 270 { 271 272 } 273 274 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 275 { 276 struct rt_cache_stat *st = v; 277 278 if (v == SEQ_START_TOKEN) { 279 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"); 280 return 0; 281 } 282 283 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 284 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 285 dst_entries_get_slow(&ipv4_dst_ops), 286 0, /* st->in_hit */ 287 st->in_slow_tot, 288 st->in_slow_mc, 289 st->in_no_route, 290 st->in_brd, 291 st->in_martian_dst, 292 st->in_martian_src, 293 294 0, /* st->out_hit */ 295 st->out_slow_tot, 296 st->out_slow_mc, 297 298 0, /* st->gc_total */ 299 0, /* st->gc_ignored */ 300 0, /* st->gc_goal_miss */ 301 0, /* st->gc_dst_overflow */ 302 0, /* st->in_hlist_search */ 303 0 /* st->out_hlist_search */ 304 ); 305 return 0; 306 } 307 308 static const struct seq_operations rt_cpu_seq_ops = { 309 .start = rt_cpu_seq_start, 310 .next = rt_cpu_seq_next, 311 .stop = rt_cpu_seq_stop, 312 .show = rt_cpu_seq_show, 313 }; 314 315 #ifdef CONFIG_IP_ROUTE_CLASSID 316 static int rt_acct_proc_show(struct seq_file *m, void *v) 317 { 318 struct ip_rt_acct *dst, *src; 319 unsigned int i, j; 320 321 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 322 if (!dst) 323 return -ENOMEM; 324 325 for_each_possible_cpu(i) { 326 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 327 for (j = 0; j < 256; j++) { 328 dst[j].o_bytes += src[j].o_bytes; 329 dst[j].o_packets += src[j].o_packets; 330 dst[j].i_bytes += src[j].i_bytes; 331 dst[j].i_packets += src[j].i_packets; 332 } 333 } 334 335 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 336 kfree(dst); 337 return 0; 338 } 339 #endif 340 341 static int __net_init ip_rt_do_proc_init(struct net *net) 342 { 343 struct proc_dir_entry *pde; 344 345 pde = proc_create_seq("rt_cache", 0444, net->proc_net, 346 &rt_cache_seq_ops); 347 if (!pde) 348 goto err1; 349 350 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat, 351 &rt_cpu_seq_ops); 352 if (!pde) 353 goto err2; 354 355 #ifdef CONFIG_IP_ROUTE_CLASSID 356 pde = proc_create_single("rt_acct", 0, net->proc_net, 357 rt_acct_proc_show); 358 if (!pde) 359 goto err3; 360 #endif 361 return 0; 362 363 #ifdef CONFIG_IP_ROUTE_CLASSID 364 err3: 365 remove_proc_entry("rt_cache", net->proc_net_stat); 366 #endif 367 err2: 368 remove_proc_entry("rt_cache", net->proc_net); 369 err1: 370 return -ENOMEM; 371 } 372 373 static void __net_exit ip_rt_do_proc_exit(struct net *net) 374 { 375 remove_proc_entry("rt_cache", net->proc_net_stat); 376 remove_proc_entry("rt_cache", net->proc_net); 377 #ifdef CONFIG_IP_ROUTE_CLASSID 378 remove_proc_entry("rt_acct", net->proc_net); 379 #endif 380 } 381 382 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 383 .init = ip_rt_do_proc_init, 384 .exit = ip_rt_do_proc_exit, 385 }; 386 387 static int __init ip_rt_proc_init(void) 388 { 389 return register_pernet_subsys(&ip_rt_proc_ops); 390 } 391 392 #else 393 static inline int ip_rt_proc_init(void) 394 { 395 return 0; 396 } 397 #endif /* CONFIG_PROC_FS */ 398 399 static inline bool rt_is_expired(const struct rtable *rth) 400 { 401 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 402 } 403 404 void rt_cache_flush(struct net *net) 405 { 406 rt_genid_bump_ipv4(net); 407 } 408 409 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 410 struct sk_buff *skb, 411 const void *daddr) 412 { 413 const struct rtable *rt = container_of(dst, struct rtable, dst); 414 struct net_device *dev = dst->dev; 415 struct neighbour *n; 416 417 rcu_read_lock_bh(); 418 419 if (likely(rt->rt_gw_family == AF_INET)) { 420 n = ip_neigh_gw4(dev, rt->rt_gw4); 421 } else if (rt->rt_gw_family == AF_INET6) { 422 n = ip_neigh_gw6(dev, &rt->rt_gw6); 423 } else { 424 __be32 pkey; 425 426 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 427 n = ip_neigh_gw4(dev, pkey); 428 } 429 430 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 431 n = NULL; 432 433 rcu_read_unlock_bh(); 434 435 return n; 436 } 437 438 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 439 { 440 const struct rtable *rt = container_of(dst, struct rtable, dst); 441 struct net_device *dev = dst->dev; 442 const __be32 *pkey = daddr; 443 444 if (rt->rt_gw_family == AF_INET) { 445 pkey = (const __be32 *)&rt->rt_gw4; 446 } else if (rt->rt_gw_family == AF_INET6) { 447 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 448 } else if (!daddr || 449 (rt->rt_flags & 450 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 451 return; 452 } 453 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 454 } 455 456 /* Hash tables of size 2048..262144 depending on RAM size. 457 * Each bucket uses 8 bytes. 458 */ 459 static u32 ip_idents_mask __read_mostly; 460 static atomic_t *ip_idents __read_mostly; 461 static u32 *ip_tstamps __read_mostly; 462 463 /* In order to protect privacy, we add a perturbation to identifiers 464 * if one generator is seldom used. This makes hard for an attacker 465 * to infer how many packets were sent between two points in time. 466 */ 467 u32 ip_idents_reserve(u32 hash, int segs) 468 { 469 u32 bucket, old, now = (u32)jiffies; 470 atomic_t *p_id; 471 u32 *p_tstamp; 472 u32 delta = 0; 473 474 bucket = hash & ip_idents_mask; 475 p_tstamp = ip_tstamps + bucket; 476 p_id = ip_idents + bucket; 477 old = READ_ONCE(*p_tstamp); 478 479 if (old != now && cmpxchg(p_tstamp, old, now) == old) 480 delta = prandom_u32_max(now - old); 481 482 /* If UBSAN reports an error there, please make sure your compiler 483 * supports -fno-strict-overflow before reporting it that was a bug 484 * in UBSAN, and it has been fixed in GCC-8. 485 */ 486 return atomic_add_return(segs + delta, p_id) - segs; 487 } 488 EXPORT_SYMBOL(ip_idents_reserve); 489 490 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 491 { 492 u32 hash, id; 493 494 /* Note the following code is not safe, but this is okay. */ 495 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 496 get_random_bytes(&net->ipv4.ip_id_key, 497 sizeof(net->ipv4.ip_id_key)); 498 499 hash = siphash_3u32((__force u32)iph->daddr, 500 (__force u32)iph->saddr, 501 iph->protocol, 502 &net->ipv4.ip_id_key); 503 id = ip_idents_reserve(hash, segs); 504 iph->id = htons(id); 505 } 506 EXPORT_SYMBOL(__ip_select_ident); 507 508 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 509 const struct sock *sk, 510 const struct iphdr *iph, 511 int oif, u8 tos, 512 u8 prot, u32 mark, int flow_flags) 513 { 514 if (sk) { 515 const struct inet_sock *inet = inet_sk(sk); 516 517 oif = sk->sk_bound_dev_if; 518 mark = sk->sk_mark; 519 tos = RT_CONN_FLAGS(sk); 520 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 521 } 522 flowi4_init_output(fl4, oif, mark, tos, 523 RT_SCOPE_UNIVERSE, prot, 524 flow_flags, 525 iph->daddr, iph->saddr, 0, 0, 526 sock_net_uid(net, sk)); 527 } 528 529 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 530 const struct sock *sk) 531 { 532 const struct net *net = dev_net(skb->dev); 533 const struct iphdr *iph = ip_hdr(skb); 534 int oif = skb->dev->ifindex; 535 u8 tos = RT_TOS(iph->tos); 536 u8 prot = iph->protocol; 537 u32 mark = skb->mark; 538 539 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 540 } 541 542 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 543 { 544 const struct inet_sock *inet = inet_sk(sk); 545 const struct ip_options_rcu *inet_opt; 546 __be32 daddr = inet->inet_daddr; 547 548 rcu_read_lock(); 549 inet_opt = rcu_dereference(inet->inet_opt); 550 if (inet_opt && inet_opt->opt.srr) 551 daddr = inet_opt->opt.faddr; 552 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 553 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 554 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 555 inet_sk_flowi_flags(sk), 556 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 557 rcu_read_unlock(); 558 } 559 560 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 561 const struct sk_buff *skb) 562 { 563 if (skb) 564 build_skb_flow_key(fl4, skb, sk); 565 else 566 build_sk_flow_key(fl4, sk); 567 } 568 569 static DEFINE_SPINLOCK(fnhe_lock); 570 571 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 572 { 573 struct rtable *rt; 574 575 rt = rcu_dereference(fnhe->fnhe_rth_input); 576 if (rt) { 577 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 578 dst_dev_put(&rt->dst); 579 dst_release(&rt->dst); 580 } 581 rt = rcu_dereference(fnhe->fnhe_rth_output); 582 if (rt) { 583 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 584 dst_dev_put(&rt->dst); 585 dst_release(&rt->dst); 586 } 587 } 588 589 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 590 { 591 struct fib_nh_exception *fnhe, *oldest; 592 593 oldest = rcu_dereference(hash->chain); 594 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 595 fnhe = rcu_dereference(fnhe->fnhe_next)) { 596 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 597 oldest = fnhe; 598 } 599 fnhe_flush_routes(oldest); 600 return oldest; 601 } 602 603 static inline u32 fnhe_hashfun(__be32 daddr) 604 { 605 static u32 fnhe_hashrnd __read_mostly; 606 u32 hval; 607 608 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 609 hval = jhash_1word((__force u32)daddr, fnhe_hashrnd); 610 return hash_32(hval, FNHE_HASH_SHIFT); 611 } 612 613 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 614 { 615 rt->rt_pmtu = fnhe->fnhe_pmtu; 616 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 617 rt->dst.expires = fnhe->fnhe_expires; 618 619 if (fnhe->fnhe_gw) { 620 rt->rt_flags |= RTCF_REDIRECTED; 621 rt->rt_uses_gateway = 1; 622 rt->rt_gw_family = AF_INET; 623 rt->rt_gw4 = fnhe->fnhe_gw; 624 } 625 } 626 627 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 628 __be32 gw, u32 pmtu, bool lock, 629 unsigned long expires) 630 { 631 struct fnhe_hash_bucket *hash; 632 struct fib_nh_exception *fnhe; 633 struct rtable *rt; 634 u32 genid, hval; 635 unsigned int i; 636 int depth; 637 638 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 639 hval = fnhe_hashfun(daddr); 640 641 spin_lock_bh(&fnhe_lock); 642 643 hash = rcu_dereference(nhc->nhc_exceptions); 644 if (!hash) { 645 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 646 if (!hash) 647 goto out_unlock; 648 rcu_assign_pointer(nhc->nhc_exceptions, hash); 649 } 650 651 hash += hval; 652 653 depth = 0; 654 for (fnhe = rcu_dereference(hash->chain); fnhe; 655 fnhe = rcu_dereference(fnhe->fnhe_next)) { 656 if (fnhe->fnhe_daddr == daddr) 657 break; 658 depth++; 659 } 660 661 if (fnhe) { 662 if (fnhe->fnhe_genid != genid) 663 fnhe->fnhe_genid = genid; 664 if (gw) 665 fnhe->fnhe_gw = gw; 666 if (pmtu) { 667 fnhe->fnhe_pmtu = pmtu; 668 fnhe->fnhe_mtu_locked = lock; 669 } 670 fnhe->fnhe_expires = max(1UL, expires); 671 /* Update all cached dsts too */ 672 rt = rcu_dereference(fnhe->fnhe_rth_input); 673 if (rt) 674 fill_route_from_fnhe(rt, fnhe); 675 rt = rcu_dereference(fnhe->fnhe_rth_output); 676 if (rt) 677 fill_route_from_fnhe(rt, fnhe); 678 } else { 679 if (depth > FNHE_RECLAIM_DEPTH) 680 fnhe = fnhe_oldest(hash); 681 else { 682 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 683 if (!fnhe) 684 goto out_unlock; 685 686 fnhe->fnhe_next = hash->chain; 687 rcu_assign_pointer(hash->chain, fnhe); 688 } 689 fnhe->fnhe_genid = genid; 690 fnhe->fnhe_daddr = daddr; 691 fnhe->fnhe_gw = gw; 692 fnhe->fnhe_pmtu = pmtu; 693 fnhe->fnhe_mtu_locked = lock; 694 fnhe->fnhe_expires = max(1UL, expires); 695 696 /* Exception created; mark the cached routes for the nexthop 697 * stale, so anyone caching it rechecks if this exception 698 * applies to them. 699 */ 700 rt = rcu_dereference(nhc->nhc_rth_input); 701 if (rt) 702 rt->dst.obsolete = DST_OBSOLETE_KILL; 703 704 for_each_possible_cpu(i) { 705 struct rtable __rcu **prt; 706 707 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 708 rt = rcu_dereference(*prt); 709 if (rt) 710 rt->dst.obsolete = DST_OBSOLETE_KILL; 711 } 712 } 713 714 fnhe->fnhe_stamp = jiffies; 715 716 out_unlock: 717 spin_unlock_bh(&fnhe_lock); 718 } 719 720 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 721 bool kill_route) 722 { 723 __be32 new_gw = icmp_hdr(skb)->un.gateway; 724 __be32 old_gw = ip_hdr(skb)->saddr; 725 struct net_device *dev = skb->dev; 726 struct in_device *in_dev; 727 struct fib_result res; 728 struct neighbour *n; 729 struct net *net; 730 731 switch (icmp_hdr(skb)->code & 7) { 732 case ICMP_REDIR_NET: 733 case ICMP_REDIR_NETTOS: 734 case ICMP_REDIR_HOST: 735 case ICMP_REDIR_HOSTTOS: 736 break; 737 738 default: 739 return; 740 } 741 742 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 743 return; 744 745 in_dev = __in_dev_get_rcu(dev); 746 if (!in_dev) 747 return; 748 749 net = dev_net(dev); 750 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 751 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 752 ipv4_is_zeronet(new_gw)) 753 goto reject_redirect; 754 755 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 756 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 757 goto reject_redirect; 758 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 759 goto reject_redirect; 760 } else { 761 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 762 goto reject_redirect; 763 } 764 765 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 766 if (!n) 767 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 768 if (!IS_ERR(n)) { 769 if (!(n->nud_state & NUD_VALID)) { 770 neigh_event_send(n, NULL); 771 } else { 772 if (fib_lookup(net, fl4, &res, 0) == 0) { 773 struct fib_nh_common *nhc; 774 775 fib_select_path(net, &res, fl4, skb); 776 nhc = FIB_RES_NHC(res); 777 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 778 0, false, 779 jiffies + ip_rt_gc_timeout); 780 } 781 if (kill_route) 782 rt->dst.obsolete = DST_OBSOLETE_KILL; 783 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 784 } 785 neigh_release(n); 786 } 787 return; 788 789 reject_redirect: 790 #ifdef CONFIG_IP_ROUTE_VERBOSE 791 if (IN_DEV_LOG_MARTIANS(in_dev)) { 792 const struct iphdr *iph = (const struct iphdr *) skb->data; 793 __be32 daddr = iph->daddr; 794 __be32 saddr = iph->saddr; 795 796 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 797 " Advised path = %pI4 -> %pI4\n", 798 &old_gw, dev->name, &new_gw, 799 &saddr, &daddr); 800 } 801 #endif 802 ; 803 } 804 805 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 806 { 807 struct rtable *rt; 808 struct flowi4 fl4; 809 const struct iphdr *iph = (const struct iphdr *) skb->data; 810 struct net *net = dev_net(skb->dev); 811 int oif = skb->dev->ifindex; 812 u8 tos = RT_TOS(iph->tos); 813 u8 prot = iph->protocol; 814 u32 mark = skb->mark; 815 816 rt = (struct rtable *) dst; 817 818 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 819 __ip_do_redirect(rt, skb, &fl4, true); 820 } 821 822 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 823 { 824 struct rtable *rt = (struct rtable *)dst; 825 struct dst_entry *ret = dst; 826 827 if (rt) { 828 if (dst->obsolete > 0) { 829 ip_rt_put(rt); 830 ret = NULL; 831 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 832 rt->dst.expires) { 833 ip_rt_put(rt); 834 ret = NULL; 835 } 836 } 837 return ret; 838 } 839 840 /* 841 * Algorithm: 842 * 1. The first ip_rt_redirect_number redirects are sent 843 * with exponential backoff, then we stop sending them at all, 844 * assuming that the host ignores our redirects. 845 * 2. If we did not see packets requiring redirects 846 * during ip_rt_redirect_silence, we assume that the host 847 * forgot redirected route and start to send redirects again. 848 * 849 * This algorithm is much cheaper and more intelligent than dumb load limiting 850 * in icmp.c. 851 * 852 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 853 * and "frag. need" (breaks PMTU discovery) in icmp.c. 854 */ 855 856 void ip_rt_send_redirect(struct sk_buff *skb) 857 { 858 struct rtable *rt = skb_rtable(skb); 859 struct in_device *in_dev; 860 struct inet_peer *peer; 861 struct net *net; 862 int log_martians; 863 int vif; 864 865 rcu_read_lock(); 866 in_dev = __in_dev_get_rcu(rt->dst.dev); 867 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 868 rcu_read_unlock(); 869 return; 870 } 871 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 872 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 873 rcu_read_unlock(); 874 875 net = dev_net(rt->dst.dev); 876 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 877 if (!peer) { 878 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 879 rt_nexthop(rt, ip_hdr(skb)->daddr)); 880 return; 881 } 882 883 /* No redirected packets during ip_rt_redirect_silence; 884 * reset the algorithm. 885 */ 886 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 887 peer->rate_tokens = 0; 888 peer->n_redirects = 0; 889 } 890 891 /* Too many ignored redirects; do not send anything 892 * set dst.rate_last to the last seen redirected packet. 893 */ 894 if (peer->n_redirects >= ip_rt_redirect_number) { 895 peer->rate_last = jiffies; 896 goto out_put_peer; 897 } 898 899 /* Check for load limit; set rate_last to the latest sent 900 * redirect. 901 */ 902 if (peer->n_redirects == 0 || 903 time_after(jiffies, 904 (peer->rate_last + 905 (ip_rt_redirect_load << peer->n_redirects)))) { 906 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 907 908 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 909 peer->rate_last = jiffies; 910 ++peer->n_redirects; 911 #ifdef CONFIG_IP_ROUTE_VERBOSE 912 if (log_martians && 913 peer->n_redirects == ip_rt_redirect_number) 914 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 915 &ip_hdr(skb)->saddr, inet_iif(skb), 916 &ip_hdr(skb)->daddr, &gw); 917 #endif 918 } 919 out_put_peer: 920 inet_putpeer(peer); 921 } 922 923 static int ip_error(struct sk_buff *skb) 924 { 925 struct rtable *rt = skb_rtable(skb); 926 struct net_device *dev = skb->dev; 927 struct in_device *in_dev; 928 struct inet_peer *peer; 929 unsigned long now; 930 struct net *net; 931 bool send; 932 int code; 933 934 if (netif_is_l3_master(skb->dev)) { 935 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 936 if (!dev) 937 goto out; 938 } 939 940 in_dev = __in_dev_get_rcu(dev); 941 942 /* IP on this device is disabled. */ 943 if (!in_dev) 944 goto out; 945 946 net = dev_net(rt->dst.dev); 947 if (!IN_DEV_FORWARD(in_dev)) { 948 switch (rt->dst.error) { 949 case EHOSTUNREACH: 950 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 951 break; 952 953 case ENETUNREACH: 954 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 955 break; 956 } 957 goto out; 958 } 959 960 switch (rt->dst.error) { 961 case EINVAL: 962 default: 963 goto out; 964 case EHOSTUNREACH: 965 code = ICMP_HOST_UNREACH; 966 break; 967 case ENETUNREACH: 968 code = ICMP_NET_UNREACH; 969 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 970 break; 971 case EACCES: 972 code = ICMP_PKT_FILTERED; 973 break; 974 } 975 976 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 977 l3mdev_master_ifindex(skb->dev), 1); 978 979 send = true; 980 if (peer) { 981 now = jiffies; 982 peer->rate_tokens += now - peer->rate_last; 983 if (peer->rate_tokens > ip_rt_error_burst) 984 peer->rate_tokens = ip_rt_error_burst; 985 peer->rate_last = now; 986 if (peer->rate_tokens >= ip_rt_error_cost) 987 peer->rate_tokens -= ip_rt_error_cost; 988 else 989 send = false; 990 inet_putpeer(peer); 991 } 992 if (send) 993 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 994 995 out: kfree_skb(skb); 996 return 0; 997 } 998 999 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1000 { 1001 struct dst_entry *dst = &rt->dst; 1002 struct net *net = dev_net(dst->dev); 1003 struct fib_result res; 1004 bool lock = false; 1005 u32 old_mtu; 1006 1007 if (ip_mtu_locked(dst)) 1008 return; 1009 1010 old_mtu = ipv4_mtu(dst); 1011 if (old_mtu < mtu) 1012 return; 1013 1014 if (mtu < ip_rt_min_pmtu) { 1015 lock = true; 1016 mtu = min(old_mtu, ip_rt_min_pmtu); 1017 } 1018 1019 if (rt->rt_pmtu == mtu && !lock && 1020 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1021 return; 1022 1023 rcu_read_lock(); 1024 if (fib_lookup(net, fl4, &res, 0) == 0) { 1025 struct fib_nh_common *nhc; 1026 1027 fib_select_path(net, &res, fl4, NULL); 1028 nhc = FIB_RES_NHC(res); 1029 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1030 jiffies + ip_rt_mtu_expires); 1031 } 1032 rcu_read_unlock(); 1033 } 1034 1035 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1036 struct sk_buff *skb, u32 mtu, 1037 bool confirm_neigh) 1038 { 1039 struct rtable *rt = (struct rtable *) dst; 1040 struct flowi4 fl4; 1041 1042 ip_rt_build_flow_key(&fl4, sk, skb); 1043 1044 /* Don't make lookup fail for bridged encapsulations */ 1045 if (skb && netif_is_any_bridge_port(skb->dev)) 1046 fl4.flowi4_oif = 0; 1047 1048 __ip_rt_update_pmtu(rt, &fl4, mtu); 1049 } 1050 1051 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1052 int oif, u8 protocol) 1053 { 1054 const struct iphdr *iph = (const struct iphdr *)skb->data; 1055 struct flowi4 fl4; 1056 struct rtable *rt; 1057 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1058 1059 __build_flow_key(net, &fl4, NULL, iph, oif, 1060 RT_TOS(iph->tos), protocol, mark, 0); 1061 rt = __ip_route_output_key(net, &fl4); 1062 if (!IS_ERR(rt)) { 1063 __ip_rt_update_pmtu(rt, &fl4, mtu); 1064 ip_rt_put(rt); 1065 } 1066 } 1067 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1068 1069 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1070 { 1071 const struct iphdr *iph = (const struct iphdr *)skb->data; 1072 struct flowi4 fl4; 1073 struct rtable *rt; 1074 1075 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1076 1077 if (!fl4.flowi4_mark) 1078 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1079 1080 rt = __ip_route_output_key(sock_net(sk), &fl4); 1081 if (!IS_ERR(rt)) { 1082 __ip_rt_update_pmtu(rt, &fl4, mtu); 1083 ip_rt_put(rt); 1084 } 1085 } 1086 1087 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1088 { 1089 const struct iphdr *iph = (const struct iphdr *)skb->data; 1090 struct flowi4 fl4; 1091 struct rtable *rt; 1092 struct dst_entry *odst = NULL; 1093 bool new = false; 1094 struct net *net = sock_net(sk); 1095 1096 bh_lock_sock(sk); 1097 1098 if (!ip_sk_accept_pmtu(sk)) 1099 goto out; 1100 1101 odst = sk_dst_get(sk); 1102 1103 if (sock_owned_by_user(sk) || !odst) { 1104 __ipv4_sk_update_pmtu(skb, sk, mtu); 1105 goto out; 1106 } 1107 1108 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1109 1110 rt = (struct rtable *)odst; 1111 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1113 if (IS_ERR(rt)) 1114 goto out; 1115 1116 new = true; 1117 } 1118 1119 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu); 1120 1121 if (!dst_check(&rt->dst, 0)) { 1122 if (new) 1123 dst_release(&rt->dst); 1124 1125 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1126 if (IS_ERR(rt)) 1127 goto out; 1128 1129 new = true; 1130 } 1131 1132 if (new) 1133 sk_dst_set(sk, &rt->dst); 1134 1135 out: 1136 bh_unlock_sock(sk); 1137 dst_release(odst); 1138 } 1139 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1140 1141 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1142 int oif, u8 protocol) 1143 { 1144 const struct iphdr *iph = (const struct iphdr *)skb->data; 1145 struct flowi4 fl4; 1146 struct rtable *rt; 1147 1148 __build_flow_key(net, &fl4, NULL, iph, oif, 1149 RT_TOS(iph->tos), protocol, 0, 0); 1150 rt = __ip_route_output_key(net, &fl4); 1151 if (!IS_ERR(rt)) { 1152 __ip_do_redirect(rt, skb, &fl4, false); 1153 ip_rt_put(rt); 1154 } 1155 } 1156 EXPORT_SYMBOL_GPL(ipv4_redirect); 1157 1158 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1159 { 1160 const struct iphdr *iph = (const struct iphdr *)skb->data; 1161 struct flowi4 fl4; 1162 struct rtable *rt; 1163 struct net *net = sock_net(sk); 1164 1165 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1166 rt = __ip_route_output_key(net, &fl4); 1167 if (!IS_ERR(rt)) { 1168 __ip_do_redirect(rt, skb, &fl4, false); 1169 ip_rt_put(rt); 1170 } 1171 } 1172 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1173 1174 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst, 1175 u32 cookie) 1176 { 1177 struct rtable *rt = (struct rtable *) dst; 1178 1179 /* All IPV4 dsts are created with ->obsolete set to the value 1180 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1181 * into this function always. 1182 * 1183 * When a PMTU/redirect information update invalidates a route, 1184 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1185 * DST_OBSOLETE_DEAD. 1186 */ 1187 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1188 return NULL; 1189 return dst; 1190 } 1191 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check); 1192 1193 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1194 { 1195 struct ip_options opt; 1196 int res; 1197 1198 /* Recompile ip options since IPCB may not be valid anymore. 1199 * Also check we have a reasonable ipv4 header. 1200 */ 1201 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1202 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1203 return; 1204 1205 memset(&opt, 0, sizeof(opt)); 1206 if (ip_hdr(skb)->ihl > 5) { 1207 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1208 return; 1209 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1210 1211 rcu_read_lock(); 1212 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1213 rcu_read_unlock(); 1214 1215 if (res) 1216 return; 1217 } 1218 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1219 } 1220 1221 static void ipv4_link_failure(struct sk_buff *skb) 1222 { 1223 struct rtable *rt; 1224 1225 ipv4_send_dest_unreach(skb); 1226 1227 rt = skb_rtable(skb); 1228 if (rt) 1229 dst_set_expires(&rt->dst, 0); 1230 } 1231 1232 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1233 { 1234 pr_debug("%s: %pI4 -> %pI4, %s\n", 1235 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1236 skb->dev ? skb->dev->name : "?"); 1237 kfree_skb(skb); 1238 WARN_ON(1); 1239 return 0; 1240 } 1241 1242 /* 1243 * We do not cache source address of outgoing interface, 1244 * because it is used only by IP RR, TS and SRR options, 1245 * so that it out of fast path. 1246 * 1247 * BTW remember: "addr" is allowed to be not aligned 1248 * in IP options! 1249 */ 1250 1251 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1252 { 1253 __be32 src; 1254 1255 if (rt_is_output_route(rt)) 1256 src = ip_hdr(skb)->saddr; 1257 else { 1258 struct fib_result res; 1259 struct iphdr *iph = ip_hdr(skb); 1260 struct flowi4 fl4 = { 1261 .daddr = iph->daddr, 1262 .saddr = iph->saddr, 1263 .flowi4_tos = RT_TOS(iph->tos), 1264 .flowi4_oif = rt->dst.dev->ifindex, 1265 .flowi4_iif = skb->dev->ifindex, 1266 .flowi4_mark = skb->mark, 1267 }; 1268 1269 rcu_read_lock(); 1270 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1271 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1272 else 1273 src = inet_select_addr(rt->dst.dev, 1274 rt_nexthop(rt, iph->daddr), 1275 RT_SCOPE_UNIVERSE); 1276 rcu_read_unlock(); 1277 } 1278 memcpy(addr, &src, 4); 1279 } 1280 1281 #ifdef CONFIG_IP_ROUTE_CLASSID 1282 static void set_class_tag(struct rtable *rt, u32 tag) 1283 { 1284 if (!(rt->dst.tclassid & 0xFFFF)) 1285 rt->dst.tclassid |= tag & 0xFFFF; 1286 if (!(rt->dst.tclassid & 0xFFFF0000)) 1287 rt->dst.tclassid |= tag & 0xFFFF0000; 1288 } 1289 #endif 1290 1291 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1292 { 1293 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1294 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1295 ip_rt_min_advmss); 1296 1297 return min(advmss, IPV4_MAX_PMTU - header_size); 1298 } 1299 1300 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst) 1301 { 1302 return ip_dst_mtu_maybe_forward(dst, false); 1303 } 1304 EXPORT_INDIRECT_CALLABLE(ipv4_mtu); 1305 1306 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1307 { 1308 struct fnhe_hash_bucket *hash; 1309 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1310 u32 hval = fnhe_hashfun(daddr); 1311 1312 spin_lock_bh(&fnhe_lock); 1313 1314 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1315 lockdep_is_held(&fnhe_lock)); 1316 hash += hval; 1317 1318 fnhe_p = &hash->chain; 1319 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1320 while (fnhe) { 1321 if (fnhe->fnhe_daddr == daddr) { 1322 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1323 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1324 /* set fnhe_daddr to 0 to ensure it won't bind with 1325 * new dsts in rt_bind_exception(). 1326 */ 1327 fnhe->fnhe_daddr = 0; 1328 fnhe_flush_routes(fnhe); 1329 kfree_rcu(fnhe, rcu); 1330 break; 1331 } 1332 fnhe_p = &fnhe->fnhe_next; 1333 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1334 lockdep_is_held(&fnhe_lock)); 1335 } 1336 1337 spin_unlock_bh(&fnhe_lock); 1338 } 1339 1340 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1341 __be32 daddr) 1342 { 1343 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1344 struct fib_nh_exception *fnhe; 1345 u32 hval; 1346 1347 if (!hash) 1348 return NULL; 1349 1350 hval = fnhe_hashfun(daddr); 1351 1352 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1353 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1354 if (fnhe->fnhe_daddr == daddr) { 1355 if (fnhe->fnhe_expires && 1356 time_after(jiffies, fnhe->fnhe_expires)) { 1357 ip_del_fnhe(nhc, daddr); 1358 break; 1359 } 1360 return fnhe; 1361 } 1362 } 1363 return NULL; 1364 } 1365 1366 /* MTU selection: 1367 * 1. mtu on route is locked - use it 1368 * 2. mtu from nexthop exception 1369 * 3. mtu from egress device 1370 */ 1371 1372 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1373 { 1374 struct fib_nh_common *nhc = res->nhc; 1375 struct net_device *dev = nhc->nhc_dev; 1376 struct fib_info *fi = res->fi; 1377 u32 mtu = 0; 1378 1379 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1380 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1381 mtu = fi->fib_mtu; 1382 1383 if (likely(!mtu)) { 1384 struct fib_nh_exception *fnhe; 1385 1386 fnhe = find_exception(nhc, daddr); 1387 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1388 mtu = fnhe->fnhe_pmtu; 1389 } 1390 1391 if (likely(!mtu)) 1392 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1393 1394 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1395 } 1396 1397 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1398 __be32 daddr, const bool do_cache) 1399 { 1400 bool ret = false; 1401 1402 spin_lock_bh(&fnhe_lock); 1403 1404 if (daddr == fnhe->fnhe_daddr) { 1405 struct rtable __rcu **porig; 1406 struct rtable *orig; 1407 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1408 1409 if (rt_is_input_route(rt)) 1410 porig = &fnhe->fnhe_rth_input; 1411 else 1412 porig = &fnhe->fnhe_rth_output; 1413 orig = rcu_dereference(*porig); 1414 1415 if (fnhe->fnhe_genid != genid) { 1416 fnhe->fnhe_genid = genid; 1417 fnhe->fnhe_gw = 0; 1418 fnhe->fnhe_pmtu = 0; 1419 fnhe->fnhe_expires = 0; 1420 fnhe->fnhe_mtu_locked = false; 1421 fnhe_flush_routes(fnhe); 1422 orig = NULL; 1423 } 1424 fill_route_from_fnhe(rt, fnhe); 1425 if (!rt->rt_gw4) { 1426 rt->rt_gw4 = daddr; 1427 rt->rt_gw_family = AF_INET; 1428 } 1429 1430 if (do_cache) { 1431 dst_hold(&rt->dst); 1432 rcu_assign_pointer(*porig, rt); 1433 if (orig) { 1434 dst_dev_put(&orig->dst); 1435 dst_release(&orig->dst); 1436 } 1437 ret = true; 1438 } 1439 1440 fnhe->fnhe_stamp = jiffies; 1441 } 1442 spin_unlock_bh(&fnhe_lock); 1443 1444 return ret; 1445 } 1446 1447 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1448 { 1449 struct rtable *orig, *prev, **p; 1450 bool ret = true; 1451 1452 if (rt_is_input_route(rt)) { 1453 p = (struct rtable **)&nhc->nhc_rth_input; 1454 } else { 1455 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1456 } 1457 orig = *p; 1458 1459 /* hold dst before doing cmpxchg() to avoid race condition 1460 * on this dst 1461 */ 1462 dst_hold(&rt->dst); 1463 prev = cmpxchg(p, orig, rt); 1464 if (prev == orig) { 1465 if (orig) { 1466 rt_add_uncached_list(orig); 1467 dst_release(&orig->dst); 1468 } 1469 } else { 1470 dst_release(&rt->dst); 1471 ret = false; 1472 } 1473 1474 return ret; 1475 } 1476 1477 struct uncached_list { 1478 spinlock_t lock; 1479 struct list_head head; 1480 }; 1481 1482 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1483 1484 void rt_add_uncached_list(struct rtable *rt) 1485 { 1486 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1487 1488 rt->rt_uncached_list = ul; 1489 1490 spin_lock_bh(&ul->lock); 1491 list_add_tail(&rt->rt_uncached, &ul->head); 1492 spin_unlock_bh(&ul->lock); 1493 } 1494 1495 void rt_del_uncached_list(struct rtable *rt) 1496 { 1497 if (!list_empty(&rt->rt_uncached)) { 1498 struct uncached_list *ul = rt->rt_uncached_list; 1499 1500 spin_lock_bh(&ul->lock); 1501 list_del(&rt->rt_uncached); 1502 spin_unlock_bh(&ul->lock); 1503 } 1504 } 1505 1506 static void ipv4_dst_destroy(struct dst_entry *dst) 1507 { 1508 struct rtable *rt = (struct rtable *)dst; 1509 1510 ip_dst_metrics_put(dst); 1511 rt_del_uncached_list(rt); 1512 } 1513 1514 void rt_flush_dev(struct net_device *dev) 1515 { 1516 struct rtable *rt; 1517 int cpu; 1518 1519 for_each_possible_cpu(cpu) { 1520 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1521 1522 spin_lock_bh(&ul->lock); 1523 list_for_each_entry(rt, &ul->head, rt_uncached) { 1524 if (rt->dst.dev != dev) 1525 continue; 1526 rt->dst.dev = blackhole_netdev; 1527 dev_hold(rt->dst.dev); 1528 dev_put(dev); 1529 } 1530 spin_unlock_bh(&ul->lock); 1531 } 1532 } 1533 1534 static bool rt_cache_valid(const struct rtable *rt) 1535 { 1536 return rt && 1537 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1538 !rt_is_expired(rt); 1539 } 1540 1541 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1542 const struct fib_result *res, 1543 struct fib_nh_exception *fnhe, 1544 struct fib_info *fi, u16 type, u32 itag, 1545 const bool do_cache) 1546 { 1547 bool cached = false; 1548 1549 if (fi) { 1550 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1551 1552 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1553 rt->rt_uses_gateway = 1; 1554 rt->rt_gw_family = nhc->nhc_gw_family; 1555 /* only INET and INET6 are supported */ 1556 if (likely(nhc->nhc_gw_family == AF_INET)) 1557 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1558 else 1559 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1560 } 1561 1562 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1563 1564 #ifdef CONFIG_IP_ROUTE_CLASSID 1565 if (nhc->nhc_family == AF_INET) { 1566 struct fib_nh *nh; 1567 1568 nh = container_of(nhc, struct fib_nh, nh_common); 1569 rt->dst.tclassid = nh->nh_tclassid; 1570 } 1571 #endif 1572 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1573 if (unlikely(fnhe)) 1574 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1575 else if (do_cache) 1576 cached = rt_cache_route(nhc, rt); 1577 if (unlikely(!cached)) { 1578 /* Routes we intend to cache in nexthop exception or 1579 * FIB nexthop have the DST_NOCACHE bit clear. 1580 * However, if we are unsuccessful at storing this 1581 * route into the cache we really need to set it. 1582 */ 1583 if (!rt->rt_gw4) { 1584 rt->rt_gw_family = AF_INET; 1585 rt->rt_gw4 = daddr; 1586 } 1587 rt_add_uncached_list(rt); 1588 } 1589 } else 1590 rt_add_uncached_list(rt); 1591 1592 #ifdef CONFIG_IP_ROUTE_CLASSID 1593 #ifdef CONFIG_IP_MULTIPLE_TABLES 1594 set_class_tag(rt, res->tclassid); 1595 #endif 1596 set_class_tag(rt, itag); 1597 #endif 1598 } 1599 1600 struct rtable *rt_dst_alloc(struct net_device *dev, 1601 unsigned int flags, u16 type, 1602 bool nopolicy, bool noxfrm) 1603 { 1604 struct rtable *rt; 1605 1606 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1607 (nopolicy ? DST_NOPOLICY : 0) | 1608 (noxfrm ? DST_NOXFRM : 0)); 1609 1610 if (rt) { 1611 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1612 rt->rt_flags = flags; 1613 rt->rt_type = type; 1614 rt->rt_is_input = 0; 1615 rt->rt_iif = 0; 1616 rt->rt_pmtu = 0; 1617 rt->rt_mtu_locked = 0; 1618 rt->rt_uses_gateway = 0; 1619 rt->rt_gw_family = 0; 1620 rt->rt_gw4 = 0; 1621 INIT_LIST_HEAD(&rt->rt_uncached); 1622 1623 rt->dst.output = ip_output; 1624 if (flags & RTCF_LOCAL) 1625 rt->dst.input = ip_local_deliver; 1626 } 1627 1628 return rt; 1629 } 1630 EXPORT_SYMBOL(rt_dst_alloc); 1631 1632 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1633 { 1634 struct rtable *new_rt; 1635 1636 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1637 rt->dst.flags); 1638 1639 if (new_rt) { 1640 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1641 new_rt->rt_flags = rt->rt_flags; 1642 new_rt->rt_type = rt->rt_type; 1643 new_rt->rt_is_input = rt->rt_is_input; 1644 new_rt->rt_iif = rt->rt_iif; 1645 new_rt->rt_pmtu = rt->rt_pmtu; 1646 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1647 new_rt->rt_gw_family = rt->rt_gw_family; 1648 if (rt->rt_gw_family == AF_INET) 1649 new_rt->rt_gw4 = rt->rt_gw4; 1650 else if (rt->rt_gw_family == AF_INET6) 1651 new_rt->rt_gw6 = rt->rt_gw6; 1652 INIT_LIST_HEAD(&new_rt->rt_uncached); 1653 1654 new_rt->dst.input = rt->dst.input; 1655 new_rt->dst.output = rt->dst.output; 1656 new_rt->dst.error = rt->dst.error; 1657 new_rt->dst.lastuse = jiffies; 1658 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1659 } 1660 return new_rt; 1661 } 1662 EXPORT_SYMBOL(rt_dst_clone); 1663 1664 /* called in rcu_read_lock() section */ 1665 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1666 u8 tos, struct net_device *dev, 1667 struct in_device *in_dev, u32 *itag) 1668 { 1669 int err; 1670 1671 /* Primary sanity checks. */ 1672 if (!in_dev) 1673 return -EINVAL; 1674 1675 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1676 skb->protocol != htons(ETH_P_IP)) 1677 return -EINVAL; 1678 1679 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1680 return -EINVAL; 1681 1682 if (ipv4_is_zeronet(saddr)) { 1683 if (!ipv4_is_local_multicast(daddr) && 1684 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1685 return -EINVAL; 1686 } else { 1687 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1688 in_dev, itag); 1689 if (err < 0) 1690 return err; 1691 } 1692 return 0; 1693 } 1694 1695 /* called in rcu_read_lock() section */ 1696 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1697 u8 tos, struct net_device *dev, int our) 1698 { 1699 struct in_device *in_dev = __in_dev_get_rcu(dev); 1700 unsigned int flags = RTCF_MULTICAST; 1701 struct rtable *rth; 1702 u32 itag = 0; 1703 int err; 1704 1705 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1706 if (err) 1707 return err; 1708 1709 if (our) 1710 flags |= RTCF_LOCAL; 1711 1712 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1713 IN_DEV_ORCONF(in_dev, NOPOLICY), false); 1714 if (!rth) 1715 return -ENOBUFS; 1716 1717 #ifdef CONFIG_IP_ROUTE_CLASSID 1718 rth->dst.tclassid = itag; 1719 #endif 1720 rth->dst.output = ip_rt_bug; 1721 rth->rt_is_input= 1; 1722 1723 #ifdef CONFIG_IP_MROUTE 1724 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1725 rth->dst.input = ip_mr_input; 1726 #endif 1727 RT_CACHE_STAT_INC(in_slow_mc); 1728 1729 skb_dst_set(skb, &rth->dst); 1730 return 0; 1731 } 1732 1733 1734 static void ip_handle_martian_source(struct net_device *dev, 1735 struct in_device *in_dev, 1736 struct sk_buff *skb, 1737 __be32 daddr, 1738 __be32 saddr) 1739 { 1740 RT_CACHE_STAT_INC(in_martian_src); 1741 #ifdef CONFIG_IP_ROUTE_VERBOSE 1742 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1743 /* 1744 * RFC1812 recommendation, if source is martian, 1745 * the only hint is MAC header. 1746 */ 1747 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1748 &daddr, &saddr, dev->name); 1749 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1750 print_hex_dump(KERN_WARNING, "ll header: ", 1751 DUMP_PREFIX_OFFSET, 16, 1, 1752 skb_mac_header(skb), 1753 dev->hard_header_len, false); 1754 } 1755 } 1756 #endif 1757 } 1758 1759 /* called in rcu_read_lock() section */ 1760 static int __mkroute_input(struct sk_buff *skb, 1761 const struct fib_result *res, 1762 struct in_device *in_dev, 1763 __be32 daddr, __be32 saddr, u32 tos) 1764 { 1765 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1766 struct net_device *dev = nhc->nhc_dev; 1767 struct fib_nh_exception *fnhe; 1768 struct rtable *rth; 1769 int err; 1770 struct in_device *out_dev; 1771 bool do_cache; 1772 u32 itag = 0; 1773 1774 /* get a working reference to the output device */ 1775 out_dev = __in_dev_get_rcu(dev); 1776 if (!out_dev) { 1777 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1778 return -EINVAL; 1779 } 1780 1781 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1782 in_dev->dev, in_dev, &itag); 1783 if (err < 0) { 1784 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1785 saddr); 1786 1787 goto cleanup; 1788 } 1789 1790 do_cache = res->fi && !itag; 1791 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1792 skb->protocol == htons(ETH_P_IP)) { 1793 __be32 gw; 1794 1795 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1796 if (IN_DEV_SHARED_MEDIA(out_dev) || 1797 inet_addr_onlink(out_dev, saddr, gw)) 1798 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1799 } 1800 1801 if (skb->protocol != htons(ETH_P_IP)) { 1802 /* Not IP (i.e. ARP). Do not create route, if it is 1803 * invalid for proxy arp. DNAT routes are always valid. 1804 * 1805 * Proxy arp feature have been extended to allow, ARP 1806 * replies back to the same interface, to support 1807 * Private VLAN switch technologies. See arp.c. 1808 */ 1809 if (out_dev == in_dev && 1810 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1811 err = -EINVAL; 1812 goto cleanup; 1813 } 1814 } 1815 1816 fnhe = find_exception(nhc, daddr); 1817 if (do_cache) { 1818 if (fnhe) 1819 rth = rcu_dereference(fnhe->fnhe_rth_input); 1820 else 1821 rth = rcu_dereference(nhc->nhc_rth_input); 1822 if (rt_cache_valid(rth)) { 1823 skb_dst_set_noref(skb, &rth->dst); 1824 goto out; 1825 } 1826 } 1827 1828 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1829 IN_DEV_ORCONF(in_dev, NOPOLICY), 1830 IN_DEV_ORCONF(out_dev, NOXFRM)); 1831 if (!rth) { 1832 err = -ENOBUFS; 1833 goto cleanup; 1834 } 1835 1836 rth->rt_is_input = 1; 1837 RT_CACHE_STAT_INC(in_slow_tot); 1838 1839 rth->dst.input = ip_forward; 1840 1841 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1842 do_cache); 1843 lwtunnel_set_redirect(&rth->dst); 1844 skb_dst_set(skb, &rth->dst); 1845 out: 1846 err = 0; 1847 cleanup: 1848 return err; 1849 } 1850 1851 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1852 /* To make ICMP packets follow the right flow, the multipath hash is 1853 * calculated from the inner IP addresses. 1854 */ 1855 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1856 struct flow_keys *hash_keys) 1857 { 1858 const struct iphdr *outer_iph = ip_hdr(skb); 1859 const struct iphdr *key_iph = outer_iph; 1860 const struct iphdr *inner_iph; 1861 const struct icmphdr *icmph; 1862 struct iphdr _inner_iph; 1863 struct icmphdr _icmph; 1864 1865 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1866 goto out; 1867 1868 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1869 goto out; 1870 1871 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1872 &_icmph); 1873 if (!icmph) 1874 goto out; 1875 1876 if (!icmp_is_err(icmph->type)) 1877 goto out; 1878 1879 inner_iph = skb_header_pointer(skb, 1880 outer_iph->ihl * 4 + sizeof(_icmph), 1881 sizeof(_inner_iph), &_inner_iph); 1882 if (!inner_iph) 1883 goto out; 1884 1885 key_iph = inner_iph; 1886 out: 1887 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1888 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1889 } 1890 1891 static u32 fib_multipath_custom_hash_outer(const struct net *net, 1892 const struct sk_buff *skb, 1893 bool *p_has_inner) 1894 { 1895 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields; 1896 struct flow_keys keys, hash_keys; 1897 1898 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 1899 return 0; 1900 1901 memset(&hash_keys, 0, sizeof(hash_keys)); 1902 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP); 1903 1904 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1905 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 1906 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1907 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 1908 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1909 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 1910 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1911 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) 1912 hash_keys.ports.src = keys.ports.src; 1913 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 1914 hash_keys.ports.dst = keys.ports.dst; 1915 1916 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION); 1917 return flow_hash_from_keys(&hash_keys); 1918 } 1919 1920 static u32 fib_multipath_custom_hash_inner(const struct net *net, 1921 const struct sk_buff *skb, 1922 bool has_inner) 1923 { 1924 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields; 1925 struct flow_keys keys, hash_keys; 1926 1927 /* We assume the packet carries an encapsulation, but if none was 1928 * encountered during dissection of the outer flow, then there is no 1929 * point in calling the flow dissector again. 1930 */ 1931 if (!has_inner) 1932 return 0; 1933 1934 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK)) 1935 return 0; 1936 1937 memset(&hash_keys, 0, sizeof(hash_keys)); 1938 skb_flow_dissect_flow_keys(skb, &keys, 0); 1939 1940 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION)) 1941 return 0; 1942 1943 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1944 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1945 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 1946 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1947 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 1948 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1949 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1950 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1951 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 1952 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1953 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 1954 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1955 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL) 1956 hash_keys.tags.flow_label = keys.tags.flow_label; 1957 } 1958 1959 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO) 1960 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1961 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT) 1962 hash_keys.ports.src = keys.ports.src; 1963 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT) 1964 hash_keys.ports.dst = keys.ports.dst; 1965 1966 return flow_hash_from_keys(&hash_keys); 1967 } 1968 1969 static u32 fib_multipath_custom_hash_skb(const struct net *net, 1970 const struct sk_buff *skb) 1971 { 1972 u32 mhash, mhash_inner; 1973 bool has_inner = true; 1974 1975 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner); 1976 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner); 1977 1978 return jhash_2words(mhash, mhash_inner, 0); 1979 } 1980 1981 static u32 fib_multipath_custom_hash_fl4(const struct net *net, 1982 const struct flowi4 *fl4) 1983 { 1984 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields; 1985 struct flow_keys hash_keys; 1986 1987 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 1988 return 0; 1989 1990 memset(&hash_keys, 0, sizeof(hash_keys)); 1991 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1992 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 1993 hash_keys.addrs.v4addrs.src = fl4->saddr; 1994 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 1995 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1996 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 1997 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1998 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) 1999 hash_keys.ports.src = fl4->fl4_sport; 2000 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 2001 hash_keys.ports.dst = fl4->fl4_dport; 2002 2003 return flow_hash_from_keys(&hash_keys); 2004 } 2005 2006 /* if skb is set it will be used and fl4 can be NULL */ 2007 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 2008 const struct sk_buff *skb, struct flow_keys *flkeys) 2009 { 2010 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 2011 struct flow_keys hash_keys; 2012 u32 mhash = 0; 2013 2014 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 2015 case 0: 2016 memset(&hash_keys, 0, sizeof(hash_keys)); 2017 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2018 if (skb) { 2019 ip_multipath_l3_keys(skb, &hash_keys); 2020 } else { 2021 hash_keys.addrs.v4addrs.src = fl4->saddr; 2022 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2023 } 2024 mhash = flow_hash_from_keys(&hash_keys); 2025 break; 2026 case 1: 2027 /* skb is currently provided only when forwarding */ 2028 if (skb) { 2029 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 2030 struct flow_keys keys; 2031 2032 /* short-circuit if we already have L4 hash present */ 2033 if (skb->l4_hash) 2034 return skb_get_hash_raw(skb) >> 1; 2035 2036 memset(&hash_keys, 0, sizeof(hash_keys)); 2037 2038 if (!flkeys) { 2039 skb_flow_dissect_flow_keys(skb, &keys, flag); 2040 flkeys = &keys; 2041 } 2042 2043 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2044 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 2045 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 2046 hash_keys.ports.src = flkeys->ports.src; 2047 hash_keys.ports.dst = flkeys->ports.dst; 2048 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 2049 } else { 2050 memset(&hash_keys, 0, sizeof(hash_keys)); 2051 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2052 hash_keys.addrs.v4addrs.src = fl4->saddr; 2053 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2054 hash_keys.ports.src = fl4->fl4_sport; 2055 hash_keys.ports.dst = fl4->fl4_dport; 2056 hash_keys.basic.ip_proto = fl4->flowi4_proto; 2057 } 2058 mhash = flow_hash_from_keys(&hash_keys); 2059 break; 2060 case 2: 2061 memset(&hash_keys, 0, sizeof(hash_keys)); 2062 /* skb is currently provided only when forwarding */ 2063 if (skb) { 2064 struct flow_keys keys; 2065 2066 skb_flow_dissect_flow_keys(skb, &keys, 0); 2067 /* Inner can be v4 or v6 */ 2068 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 2069 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2070 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 2071 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 2072 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 2073 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 2074 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 2075 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 2076 hash_keys.tags.flow_label = keys.tags.flow_label; 2077 hash_keys.basic.ip_proto = keys.basic.ip_proto; 2078 } else { 2079 /* Same as case 0 */ 2080 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2081 ip_multipath_l3_keys(skb, &hash_keys); 2082 } 2083 } else { 2084 /* Same as case 0 */ 2085 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2086 hash_keys.addrs.v4addrs.src = fl4->saddr; 2087 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2088 } 2089 mhash = flow_hash_from_keys(&hash_keys); 2090 break; 2091 case 3: 2092 if (skb) 2093 mhash = fib_multipath_custom_hash_skb(net, skb); 2094 else 2095 mhash = fib_multipath_custom_hash_fl4(net, fl4); 2096 break; 2097 } 2098 2099 if (multipath_hash) 2100 mhash = jhash_2words(mhash, multipath_hash, 0); 2101 2102 return mhash >> 1; 2103 } 2104 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2105 2106 static int ip_mkroute_input(struct sk_buff *skb, 2107 struct fib_result *res, 2108 struct in_device *in_dev, 2109 __be32 daddr, __be32 saddr, u32 tos, 2110 struct flow_keys *hkeys) 2111 { 2112 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2113 if (res->fi && fib_info_num_path(res->fi) > 1) { 2114 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2115 2116 fib_select_multipath(res, h); 2117 } 2118 #endif 2119 2120 /* create a routing cache entry */ 2121 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2122 } 2123 2124 /* Implements all the saddr-related checks as ip_route_input_slow(), 2125 * assuming daddr is valid and the destination is not a local broadcast one. 2126 * Uses the provided hint instead of performing a route lookup. 2127 */ 2128 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2129 u8 tos, struct net_device *dev, 2130 const struct sk_buff *hint) 2131 { 2132 struct in_device *in_dev = __in_dev_get_rcu(dev); 2133 struct rtable *rt = skb_rtable(hint); 2134 struct net *net = dev_net(dev); 2135 int err = -EINVAL; 2136 u32 tag = 0; 2137 2138 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2139 goto martian_source; 2140 2141 if (ipv4_is_zeronet(saddr)) 2142 goto martian_source; 2143 2144 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2145 goto martian_source; 2146 2147 if (rt->rt_type != RTN_LOCAL) 2148 goto skip_validate_source; 2149 2150 tos &= IPTOS_RT_MASK; 2151 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag); 2152 if (err < 0) 2153 goto martian_source; 2154 2155 skip_validate_source: 2156 skb_dst_copy(skb, hint); 2157 return 0; 2158 2159 martian_source: 2160 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2161 return err; 2162 } 2163 2164 /* get device for dst_alloc with local routes */ 2165 static struct net_device *ip_rt_get_dev(struct net *net, 2166 const struct fib_result *res) 2167 { 2168 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL; 2169 struct net_device *dev = NULL; 2170 2171 if (nhc) 2172 dev = l3mdev_master_dev_rcu(nhc->nhc_dev); 2173 2174 return dev ? : net->loopback_dev; 2175 } 2176 2177 /* 2178 * NOTE. We drop all the packets that has local source 2179 * addresses, because every properly looped back packet 2180 * must have correct destination already attached by output routine. 2181 * Changes in the enforced policies must be applied also to 2182 * ip_route_use_hint(). 2183 * 2184 * Such approach solves two big problems: 2185 * 1. Not simplex devices are handled properly. 2186 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2187 * called with rcu_read_lock() 2188 */ 2189 2190 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2191 u8 tos, struct net_device *dev, 2192 struct fib_result *res) 2193 { 2194 struct in_device *in_dev = __in_dev_get_rcu(dev); 2195 struct flow_keys *flkeys = NULL, _flkeys; 2196 struct net *net = dev_net(dev); 2197 struct ip_tunnel_info *tun_info; 2198 int err = -EINVAL; 2199 unsigned int flags = 0; 2200 u32 itag = 0; 2201 struct rtable *rth; 2202 struct flowi4 fl4; 2203 bool do_cache = true; 2204 2205 /* IP on this device is disabled. */ 2206 2207 if (!in_dev) 2208 goto out; 2209 2210 /* Check for the most weird martians, which can be not detected 2211 * by fib_lookup. 2212 */ 2213 2214 tun_info = skb_tunnel_info(skb); 2215 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2216 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2217 else 2218 fl4.flowi4_tun_key.tun_id = 0; 2219 skb_dst_drop(skb); 2220 2221 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2222 goto martian_source; 2223 2224 res->fi = NULL; 2225 res->table = NULL; 2226 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2227 goto brd_input; 2228 2229 /* Accept zero addresses only to limited broadcast; 2230 * I even do not know to fix it or not. Waiting for complains :-) 2231 */ 2232 if (ipv4_is_zeronet(saddr)) 2233 goto martian_source; 2234 2235 if (ipv4_is_zeronet(daddr)) 2236 goto martian_destination; 2237 2238 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2239 * and call it once if daddr or/and saddr are loopback addresses 2240 */ 2241 if (ipv4_is_loopback(daddr)) { 2242 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2243 goto martian_destination; 2244 } else if (ipv4_is_loopback(saddr)) { 2245 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2246 goto martian_source; 2247 } 2248 2249 /* 2250 * Now we are ready to route packet. 2251 */ 2252 fl4.flowi4_oif = 0; 2253 fl4.flowi4_iif = dev->ifindex; 2254 fl4.flowi4_mark = skb->mark; 2255 fl4.flowi4_tos = tos; 2256 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2257 fl4.flowi4_flags = 0; 2258 fl4.daddr = daddr; 2259 fl4.saddr = saddr; 2260 fl4.flowi4_uid = sock_net_uid(net, NULL); 2261 fl4.flowi4_multipath_hash = 0; 2262 2263 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2264 flkeys = &_flkeys; 2265 } else { 2266 fl4.flowi4_proto = 0; 2267 fl4.fl4_sport = 0; 2268 fl4.fl4_dport = 0; 2269 } 2270 2271 err = fib_lookup(net, &fl4, res, 0); 2272 if (err != 0) { 2273 if (!IN_DEV_FORWARD(in_dev)) 2274 err = -EHOSTUNREACH; 2275 goto no_route; 2276 } 2277 2278 if (res->type == RTN_BROADCAST) { 2279 if (IN_DEV_BFORWARD(in_dev)) 2280 goto make_route; 2281 /* not do cache if bc_forwarding is enabled */ 2282 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2283 do_cache = false; 2284 goto brd_input; 2285 } 2286 2287 if (res->type == RTN_LOCAL) { 2288 err = fib_validate_source(skb, saddr, daddr, tos, 2289 0, dev, in_dev, &itag); 2290 if (err < 0) 2291 goto martian_source; 2292 goto local_input; 2293 } 2294 2295 if (!IN_DEV_FORWARD(in_dev)) { 2296 err = -EHOSTUNREACH; 2297 goto no_route; 2298 } 2299 if (res->type != RTN_UNICAST) 2300 goto martian_destination; 2301 2302 make_route: 2303 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2304 out: return err; 2305 2306 brd_input: 2307 if (skb->protocol != htons(ETH_P_IP)) 2308 goto e_inval; 2309 2310 if (!ipv4_is_zeronet(saddr)) { 2311 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2312 in_dev, &itag); 2313 if (err < 0) 2314 goto martian_source; 2315 } 2316 flags |= RTCF_BROADCAST; 2317 res->type = RTN_BROADCAST; 2318 RT_CACHE_STAT_INC(in_brd); 2319 2320 local_input: 2321 do_cache &= res->fi && !itag; 2322 if (do_cache) { 2323 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2324 2325 rth = rcu_dereference(nhc->nhc_rth_input); 2326 if (rt_cache_valid(rth)) { 2327 skb_dst_set_noref(skb, &rth->dst); 2328 err = 0; 2329 goto out; 2330 } 2331 } 2332 2333 rth = rt_dst_alloc(ip_rt_get_dev(net, res), 2334 flags | RTCF_LOCAL, res->type, 2335 IN_DEV_ORCONF(in_dev, NOPOLICY), false); 2336 if (!rth) 2337 goto e_nobufs; 2338 2339 rth->dst.output= ip_rt_bug; 2340 #ifdef CONFIG_IP_ROUTE_CLASSID 2341 rth->dst.tclassid = itag; 2342 #endif 2343 rth->rt_is_input = 1; 2344 2345 RT_CACHE_STAT_INC(in_slow_tot); 2346 if (res->type == RTN_UNREACHABLE) { 2347 rth->dst.input= ip_error; 2348 rth->dst.error= -err; 2349 rth->rt_flags &= ~RTCF_LOCAL; 2350 } 2351 2352 if (do_cache) { 2353 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2354 2355 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2356 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2357 WARN_ON(rth->dst.input == lwtunnel_input); 2358 rth->dst.lwtstate->orig_input = rth->dst.input; 2359 rth->dst.input = lwtunnel_input; 2360 } 2361 2362 if (unlikely(!rt_cache_route(nhc, rth))) 2363 rt_add_uncached_list(rth); 2364 } 2365 skb_dst_set(skb, &rth->dst); 2366 err = 0; 2367 goto out; 2368 2369 no_route: 2370 RT_CACHE_STAT_INC(in_no_route); 2371 res->type = RTN_UNREACHABLE; 2372 res->fi = NULL; 2373 res->table = NULL; 2374 goto local_input; 2375 2376 /* 2377 * Do not cache martian addresses: they should be logged (RFC1812) 2378 */ 2379 martian_destination: 2380 RT_CACHE_STAT_INC(in_martian_dst); 2381 #ifdef CONFIG_IP_ROUTE_VERBOSE 2382 if (IN_DEV_LOG_MARTIANS(in_dev)) 2383 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2384 &daddr, &saddr, dev->name); 2385 #endif 2386 2387 e_inval: 2388 err = -EINVAL; 2389 goto out; 2390 2391 e_nobufs: 2392 err = -ENOBUFS; 2393 goto out; 2394 2395 martian_source: 2396 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2397 goto out; 2398 } 2399 2400 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2401 u8 tos, struct net_device *dev) 2402 { 2403 struct fib_result res; 2404 int err; 2405 2406 tos &= IPTOS_RT_MASK; 2407 rcu_read_lock(); 2408 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2409 rcu_read_unlock(); 2410 2411 return err; 2412 } 2413 EXPORT_SYMBOL(ip_route_input_noref); 2414 2415 /* called with rcu_read_lock held */ 2416 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2417 u8 tos, struct net_device *dev, struct fib_result *res) 2418 { 2419 /* Multicast recognition logic is moved from route cache to here. 2420 * The problem was that too many Ethernet cards have broken/missing 2421 * hardware multicast filters :-( As result the host on multicasting 2422 * network acquires a lot of useless route cache entries, sort of 2423 * SDR messages from all the world. Now we try to get rid of them. 2424 * Really, provided software IP multicast filter is organized 2425 * reasonably (at least, hashed), it does not result in a slowdown 2426 * comparing with route cache reject entries. 2427 * Note, that multicast routers are not affected, because 2428 * route cache entry is created eventually. 2429 */ 2430 if (ipv4_is_multicast(daddr)) { 2431 struct in_device *in_dev = __in_dev_get_rcu(dev); 2432 int our = 0; 2433 int err = -EINVAL; 2434 2435 if (!in_dev) 2436 return err; 2437 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2438 ip_hdr(skb)->protocol); 2439 2440 /* check l3 master if no match yet */ 2441 if (!our && netif_is_l3_slave(dev)) { 2442 struct in_device *l3_in_dev; 2443 2444 l3_in_dev = __in_dev_get_rcu(skb->dev); 2445 if (l3_in_dev) 2446 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2447 ip_hdr(skb)->protocol); 2448 } 2449 2450 if (our 2451 #ifdef CONFIG_IP_MROUTE 2452 || 2453 (!ipv4_is_local_multicast(daddr) && 2454 IN_DEV_MFORWARD(in_dev)) 2455 #endif 2456 ) { 2457 err = ip_route_input_mc(skb, daddr, saddr, 2458 tos, dev, our); 2459 } 2460 return err; 2461 } 2462 2463 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2464 } 2465 2466 /* called with rcu_read_lock() */ 2467 static struct rtable *__mkroute_output(const struct fib_result *res, 2468 const struct flowi4 *fl4, int orig_oif, 2469 struct net_device *dev_out, 2470 unsigned int flags) 2471 { 2472 struct fib_info *fi = res->fi; 2473 struct fib_nh_exception *fnhe; 2474 struct in_device *in_dev; 2475 u16 type = res->type; 2476 struct rtable *rth; 2477 bool do_cache; 2478 2479 in_dev = __in_dev_get_rcu(dev_out); 2480 if (!in_dev) 2481 return ERR_PTR(-EINVAL); 2482 2483 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2484 if (ipv4_is_loopback(fl4->saddr) && 2485 !(dev_out->flags & IFF_LOOPBACK) && 2486 !netif_is_l3_master(dev_out)) 2487 return ERR_PTR(-EINVAL); 2488 2489 if (ipv4_is_lbcast(fl4->daddr)) 2490 type = RTN_BROADCAST; 2491 else if (ipv4_is_multicast(fl4->daddr)) 2492 type = RTN_MULTICAST; 2493 else if (ipv4_is_zeronet(fl4->daddr)) 2494 return ERR_PTR(-EINVAL); 2495 2496 if (dev_out->flags & IFF_LOOPBACK) 2497 flags |= RTCF_LOCAL; 2498 2499 do_cache = true; 2500 if (type == RTN_BROADCAST) { 2501 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2502 fi = NULL; 2503 } else if (type == RTN_MULTICAST) { 2504 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2505 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2506 fl4->flowi4_proto)) 2507 flags &= ~RTCF_LOCAL; 2508 else 2509 do_cache = false; 2510 /* If multicast route do not exist use 2511 * default one, but do not gateway in this case. 2512 * Yes, it is hack. 2513 */ 2514 if (fi && res->prefixlen < 4) 2515 fi = NULL; 2516 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2517 (orig_oif != dev_out->ifindex)) { 2518 /* For local routes that require a particular output interface 2519 * we do not want to cache the result. Caching the result 2520 * causes incorrect behaviour when there are multiple source 2521 * addresses on the interface, the end result being that if the 2522 * intended recipient is waiting on that interface for the 2523 * packet he won't receive it because it will be delivered on 2524 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2525 * be set to the loopback interface as well. 2526 */ 2527 do_cache = false; 2528 } 2529 2530 fnhe = NULL; 2531 do_cache &= fi != NULL; 2532 if (fi) { 2533 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2534 struct rtable __rcu **prth; 2535 2536 fnhe = find_exception(nhc, fl4->daddr); 2537 if (!do_cache) 2538 goto add; 2539 if (fnhe) { 2540 prth = &fnhe->fnhe_rth_output; 2541 } else { 2542 if (unlikely(fl4->flowi4_flags & 2543 FLOWI_FLAG_KNOWN_NH && 2544 !(nhc->nhc_gw_family && 2545 nhc->nhc_scope == RT_SCOPE_LINK))) { 2546 do_cache = false; 2547 goto add; 2548 } 2549 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2550 } 2551 rth = rcu_dereference(*prth); 2552 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2553 return rth; 2554 } 2555 2556 add: 2557 rth = rt_dst_alloc(dev_out, flags, type, 2558 IN_DEV_ORCONF(in_dev, NOPOLICY), 2559 IN_DEV_ORCONF(in_dev, NOXFRM)); 2560 if (!rth) 2561 return ERR_PTR(-ENOBUFS); 2562 2563 rth->rt_iif = orig_oif; 2564 2565 RT_CACHE_STAT_INC(out_slow_tot); 2566 2567 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2568 if (flags & RTCF_LOCAL && 2569 !(dev_out->flags & IFF_LOOPBACK)) { 2570 rth->dst.output = ip_mc_output; 2571 RT_CACHE_STAT_INC(out_slow_mc); 2572 } 2573 #ifdef CONFIG_IP_MROUTE 2574 if (type == RTN_MULTICAST) { 2575 if (IN_DEV_MFORWARD(in_dev) && 2576 !ipv4_is_local_multicast(fl4->daddr)) { 2577 rth->dst.input = ip_mr_input; 2578 rth->dst.output = ip_mc_output; 2579 } 2580 } 2581 #endif 2582 } 2583 2584 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2585 lwtunnel_set_redirect(&rth->dst); 2586 2587 return rth; 2588 } 2589 2590 /* 2591 * Major route resolver routine. 2592 */ 2593 2594 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2595 const struct sk_buff *skb) 2596 { 2597 __u8 tos = RT_FL_TOS(fl4); 2598 struct fib_result res = { 2599 .type = RTN_UNSPEC, 2600 .fi = NULL, 2601 .table = NULL, 2602 .tclassid = 0, 2603 }; 2604 struct rtable *rth; 2605 2606 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2607 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2608 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2609 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2610 2611 rcu_read_lock(); 2612 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2613 rcu_read_unlock(); 2614 2615 return rth; 2616 } 2617 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2618 2619 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2620 struct fib_result *res, 2621 const struct sk_buff *skb) 2622 { 2623 struct net_device *dev_out = NULL; 2624 int orig_oif = fl4->flowi4_oif; 2625 unsigned int flags = 0; 2626 struct rtable *rth; 2627 int err; 2628 2629 if (fl4->saddr) { 2630 if (ipv4_is_multicast(fl4->saddr) || 2631 ipv4_is_lbcast(fl4->saddr) || 2632 ipv4_is_zeronet(fl4->saddr)) { 2633 rth = ERR_PTR(-EINVAL); 2634 goto out; 2635 } 2636 2637 rth = ERR_PTR(-ENETUNREACH); 2638 2639 /* I removed check for oif == dev_out->oif here. 2640 * It was wrong for two reasons: 2641 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2642 * is assigned to multiple interfaces. 2643 * 2. Moreover, we are allowed to send packets with saddr 2644 * of another iface. --ANK 2645 */ 2646 2647 if (fl4->flowi4_oif == 0 && 2648 (ipv4_is_multicast(fl4->daddr) || 2649 ipv4_is_lbcast(fl4->daddr))) { 2650 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2651 dev_out = __ip_dev_find(net, fl4->saddr, false); 2652 if (!dev_out) 2653 goto out; 2654 2655 /* Special hack: user can direct multicasts 2656 * and limited broadcast via necessary interface 2657 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2658 * This hack is not just for fun, it allows 2659 * vic,vat and friends to work. 2660 * They bind socket to loopback, set ttl to zero 2661 * and expect that it will work. 2662 * From the viewpoint of routing cache they are broken, 2663 * because we are not allowed to build multicast path 2664 * with loopback source addr (look, routing cache 2665 * cannot know, that ttl is zero, so that packet 2666 * will not leave this host and route is valid). 2667 * Luckily, this hack is good workaround. 2668 */ 2669 2670 fl4->flowi4_oif = dev_out->ifindex; 2671 goto make_route; 2672 } 2673 2674 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2675 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2676 if (!__ip_dev_find(net, fl4->saddr, false)) 2677 goto out; 2678 } 2679 } 2680 2681 2682 if (fl4->flowi4_oif) { 2683 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2684 rth = ERR_PTR(-ENODEV); 2685 if (!dev_out) 2686 goto out; 2687 2688 /* RACE: Check return value of inet_select_addr instead. */ 2689 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2690 rth = ERR_PTR(-ENETUNREACH); 2691 goto out; 2692 } 2693 if (ipv4_is_local_multicast(fl4->daddr) || 2694 ipv4_is_lbcast(fl4->daddr) || 2695 fl4->flowi4_proto == IPPROTO_IGMP) { 2696 if (!fl4->saddr) 2697 fl4->saddr = inet_select_addr(dev_out, 0, 2698 RT_SCOPE_LINK); 2699 goto make_route; 2700 } 2701 if (!fl4->saddr) { 2702 if (ipv4_is_multicast(fl4->daddr)) 2703 fl4->saddr = inet_select_addr(dev_out, 0, 2704 fl4->flowi4_scope); 2705 else if (!fl4->daddr) 2706 fl4->saddr = inet_select_addr(dev_out, 0, 2707 RT_SCOPE_HOST); 2708 } 2709 } 2710 2711 if (!fl4->daddr) { 2712 fl4->daddr = fl4->saddr; 2713 if (!fl4->daddr) 2714 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2715 dev_out = net->loopback_dev; 2716 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2717 res->type = RTN_LOCAL; 2718 flags |= RTCF_LOCAL; 2719 goto make_route; 2720 } 2721 2722 err = fib_lookup(net, fl4, res, 0); 2723 if (err) { 2724 res->fi = NULL; 2725 res->table = NULL; 2726 if (fl4->flowi4_oif && 2727 (ipv4_is_multicast(fl4->daddr) || 2728 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2729 /* Apparently, routing tables are wrong. Assume, 2730 * that the destination is on link. 2731 * 2732 * WHY? DW. 2733 * Because we are allowed to send to iface 2734 * even if it has NO routes and NO assigned 2735 * addresses. When oif is specified, routing 2736 * tables are looked up with only one purpose: 2737 * to catch if destination is gatewayed, rather than 2738 * direct. Moreover, if MSG_DONTROUTE is set, 2739 * we send packet, ignoring both routing tables 2740 * and ifaddr state. --ANK 2741 * 2742 * 2743 * We could make it even if oif is unknown, 2744 * likely IPv6, but we do not. 2745 */ 2746 2747 if (fl4->saddr == 0) 2748 fl4->saddr = inet_select_addr(dev_out, 0, 2749 RT_SCOPE_LINK); 2750 res->type = RTN_UNICAST; 2751 goto make_route; 2752 } 2753 rth = ERR_PTR(err); 2754 goto out; 2755 } 2756 2757 if (res->type == RTN_LOCAL) { 2758 if (!fl4->saddr) { 2759 if (res->fi->fib_prefsrc) 2760 fl4->saddr = res->fi->fib_prefsrc; 2761 else 2762 fl4->saddr = fl4->daddr; 2763 } 2764 2765 /* L3 master device is the loopback for that domain */ 2766 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2767 net->loopback_dev; 2768 2769 /* make sure orig_oif points to fib result device even 2770 * though packet rx/tx happens over loopback or l3mdev 2771 */ 2772 orig_oif = FIB_RES_OIF(*res); 2773 2774 fl4->flowi4_oif = dev_out->ifindex; 2775 flags |= RTCF_LOCAL; 2776 goto make_route; 2777 } 2778 2779 fib_select_path(net, res, fl4, skb); 2780 2781 dev_out = FIB_RES_DEV(*res); 2782 2783 make_route: 2784 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2785 2786 out: 2787 return rth; 2788 } 2789 2790 static struct dst_ops ipv4_dst_blackhole_ops = { 2791 .family = AF_INET, 2792 .default_advmss = ipv4_default_advmss, 2793 .neigh_lookup = ipv4_neigh_lookup, 2794 .check = dst_blackhole_check, 2795 .cow_metrics = dst_blackhole_cow_metrics, 2796 .update_pmtu = dst_blackhole_update_pmtu, 2797 .redirect = dst_blackhole_redirect, 2798 .mtu = dst_blackhole_mtu, 2799 }; 2800 2801 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2802 { 2803 struct rtable *ort = (struct rtable *) dst_orig; 2804 struct rtable *rt; 2805 2806 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2807 if (rt) { 2808 struct dst_entry *new = &rt->dst; 2809 2810 new->__use = 1; 2811 new->input = dst_discard; 2812 new->output = dst_discard_out; 2813 2814 new->dev = net->loopback_dev; 2815 if (new->dev) 2816 dev_hold(new->dev); 2817 2818 rt->rt_is_input = ort->rt_is_input; 2819 rt->rt_iif = ort->rt_iif; 2820 rt->rt_pmtu = ort->rt_pmtu; 2821 rt->rt_mtu_locked = ort->rt_mtu_locked; 2822 2823 rt->rt_genid = rt_genid_ipv4(net); 2824 rt->rt_flags = ort->rt_flags; 2825 rt->rt_type = ort->rt_type; 2826 rt->rt_uses_gateway = ort->rt_uses_gateway; 2827 rt->rt_gw_family = ort->rt_gw_family; 2828 if (rt->rt_gw_family == AF_INET) 2829 rt->rt_gw4 = ort->rt_gw4; 2830 else if (rt->rt_gw_family == AF_INET6) 2831 rt->rt_gw6 = ort->rt_gw6; 2832 2833 INIT_LIST_HEAD(&rt->rt_uncached); 2834 } 2835 2836 dst_release(dst_orig); 2837 2838 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2839 } 2840 2841 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2842 const struct sock *sk) 2843 { 2844 struct rtable *rt = __ip_route_output_key(net, flp4); 2845 2846 if (IS_ERR(rt)) 2847 return rt; 2848 2849 if (flp4->flowi4_proto) { 2850 flp4->flowi4_oif = rt->dst.dev->ifindex; 2851 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2852 flowi4_to_flowi(flp4), 2853 sk, 0); 2854 } 2855 2856 return rt; 2857 } 2858 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2859 2860 struct rtable *ip_route_output_tunnel(struct sk_buff *skb, 2861 struct net_device *dev, 2862 struct net *net, __be32 *saddr, 2863 const struct ip_tunnel_info *info, 2864 u8 protocol, bool use_cache) 2865 { 2866 #ifdef CONFIG_DST_CACHE 2867 struct dst_cache *dst_cache; 2868 #endif 2869 struct rtable *rt = NULL; 2870 struct flowi4 fl4; 2871 __u8 tos; 2872 2873 #ifdef CONFIG_DST_CACHE 2874 dst_cache = (struct dst_cache *)&info->dst_cache; 2875 if (use_cache) { 2876 rt = dst_cache_get_ip4(dst_cache, saddr); 2877 if (rt) 2878 return rt; 2879 } 2880 #endif 2881 memset(&fl4, 0, sizeof(fl4)); 2882 fl4.flowi4_mark = skb->mark; 2883 fl4.flowi4_proto = protocol; 2884 fl4.daddr = info->key.u.ipv4.dst; 2885 fl4.saddr = info->key.u.ipv4.src; 2886 tos = info->key.tos; 2887 fl4.flowi4_tos = RT_TOS(tos); 2888 2889 rt = ip_route_output_key(net, &fl4); 2890 if (IS_ERR(rt)) { 2891 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr); 2892 return ERR_PTR(-ENETUNREACH); 2893 } 2894 if (rt->dst.dev == dev) { /* is this necessary? */ 2895 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr); 2896 ip_rt_put(rt); 2897 return ERR_PTR(-ELOOP); 2898 } 2899 #ifdef CONFIG_DST_CACHE 2900 if (use_cache) 2901 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr); 2902 #endif 2903 *saddr = fl4.saddr; 2904 return rt; 2905 } 2906 EXPORT_SYMBOL_GPL(ip_route_output_tunnel); 2907 2908 /* called with rcu_read_lock held */ 2909 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2910 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2911 struct sk_buff *skb, u32 portid, u32 seq, 2912 unsigned int flags) 2913 { 2914 struct rtmsg *r; 2915 struct nlmsghdr *nlh; 2916 unsigned long expires = 0; 2917 u32 error; 2918 u32 metrics[RTAX_MAX]; 2919 2920 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2921 if (!nlh) 2922 return -EMSGSIZE; 2923 2924 r = nlmsg_data(nlh); 2925 r->rtm_family = AF_INET; 2926 r->rtm_dst_len = 32; 2927 r->rtm_src_len = 0; 2928 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2929 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2930 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2931 goto nla_put_failure; 2932 r->rtm_type = rt->rt_type; 2933 r->rtm_scope = RT_SCOPE_UNIVERSE; 2934 r->rtm_protocol = RTPROT_UNSPEC; 2935 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2936 if (rt->rt_flags & RTCF_NOTIFY) 2937 r->rtm_flags |= RTM_F_NOTIFY; 2938 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2939 r->rtm_flags |= RTCF_DOREDIRECT; 2940 2941 if (nla_put_in_addr(skb, RTA_DST, dst)) 2942 goto nla_put_failure; 2943 if (src) { 2944 r->rtm_src_len = 32; 2945 if (nla_put_in_addr(skb, RTA_SRC, src)) 2946 goto nla_put_failure; 2947 } 2948 if (rt->dst.dev && 2949 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2950 goto nla_put_failure; 2951 if (rt->dst.lwtstate && 2952 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 2953 goto nla_put_failure; 2954 #ifdef CONFIG_IP_ROUTE_CLASSID 2955 if (rt->dst.tclassid && 2956 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2957 goto nla_put_failure; 2958 #endif 2959 if (fl4 && !rt_is_input_route(rt) && 2960 fl4->saddr != src) { 2961 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2962 goto nla_put_failure; 2963 } 2964 if (rt->rt_uses_gateway) { 2965 if (rt->rt_gw_family == AF_INET && 2966 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2967 goto nla_put_failure; 2968 } else if (rt->rt_gw_family == AF_INET6) { 2969 int alen = sizeof(struct in6_addr); 2970 struct nlattr *nla; 2971 struct rtvia *via; 2972 2973 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2974 if (!nla) 2975 goto nla_put_failure; 2976 2977 via = nla_data(nla); 2978 via->rtvia_family = AF_INET6; 2979 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2980 } 2981 } 2982 2983 expires = rt->dst.expires; 2984 if (expires) { 2985 unsigned long now = jiffies; 2986 2987 if (time_before(now, expires)) 2988 expires -= now; 2989 else 2990 expires = 0; 2991 } 2992 2993 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2994 if (rt->rt_pmtu && expires) 2995 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2996 if (rt->rt_mtu_locked && expires) 2997 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2998 if (rtnetlink_put_metrics(skb, metrics) < 0) 2999 goto nla_put_failure; 3000 3001 if (fl4) { 3002 if (fl4->flowi4_mark && 3003 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 3004 goto nla_put_failure; 3005 3006 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 3007 nla_put_u32(skb, RTA_UID, 3008 from_kuid_munged(current_user_ns(), 3009 fl4->flowi4_uid))) 3010 goto nla_put_failure; 3011 3012 if (rt_is_input_route(rt)) { 3013 #ifdef CONFIG_IP_MROUTE 3014 if (ipv4_is_multicast(dst) && 3015 !ipv4_is_local_multicast(dst) && 3016 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 3017 int err = ipmr_get_route(net, skb, 3018 fl4->saddr, fl4->daddr, 3019 r, portid); 3020 3021 if (err <= 0) { 3022 if (err == 0) 3023 return 0; 3024 goto nla_put_failure; 3025 } 3026 } else 3027 #endif 3028 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 3029 goto nla_put_failure; 3030 } 3031 } 3032 3033 error = rt->dst.error; 3034 3035 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 3036 goto nla_put_failure; 3037 3038 nlmsg_end(skb, nlh); 3039 return 0; 3040 3041 nla_put_failure: 3042 nlmsg_cancel(skb, nlh); 3043 return -EMSGSIZE; 3044 } 3045 3046 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 3047 struct netlink_callback *cb, u32 table_id, 3048 struct fnhe_hash_bucket *bucket, int genid, 3049 int *fa_index, int fa_start, unsigned int flags) 3050 { 3051 int i; 3052 3053 for (i = 0; i < FNHE_HASH_SIZE; i++) { 3054 struct fib_nh_exception *fnhe; 3055 3056 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 3057 fnhe = rcu_dereference(fnhe->fnhe_next)) { 3058 struct rtable *rt; 3059 int err; 3060 3061 if (*fa_index < fa_start) 3062 goto next; 3063 3064 if (fnhe->fnhe_genid != genid) 3065 goto next; 3066 3067 if (fnhe->fnhe_expires && 3068 time_after(jiffies, fnhe->fnhe_expires)) 3069 goto next; 3070 3071 rt = rcu_dereference(fnhe->fnhe_rth_input); 3072 if (!rt) 3073 rt = rcu_dereference(fnhe->fnhe_rth_output); 3074 if (!rt) 3075 goto next; 3076 3077 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 3078 table_id, NULL, skb, 3079 NETLINK_CB(cb->skb).portid, 3080 cb->nlh->nlmsg_seq, flags); 3081 if (err) 3082 return err; 3083 next: 3084 (*fa_index)++; 3085 } 3086 } 3087 3088 return 0; 3089 } 3090 3091 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 3092 u32 table_id, struct fib_info *fi, 3093 int *fa_index, int fa_start, unsigned int flags) 3094 { 3095 struct net *net = sock_net(cb->skb->sk); 3096 int nhsel, genid = fnhe_genid(net); 3097 3098 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 3099 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 3100 struct fnhe_hash_bucket *bucket; 3101 int err; 3102 3103 if (nhc->nhc_flags & RTNH_F_DEAD) 3104 continue; 3105 3106 rcu_read_lock(); 3107 bucket = rcu_dereference(nhc->nhc_exceptions); 3108 err = 0; 3109 if (bucket) 3110 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 3111 genid, fa_index, fa_start, 3112 flags); 3113 rcu_read_unlock(); 3114 if (err) 3115 return err; 3116 } 3117 3118 return 0; 3119 } 3120 3121 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3122 u8 ip_proto, __be16 sport, 3123 __be16 dport) 3124 { 3125 struct sk_buff *skb; 3126 struct iphdr *iph; 3127 3128 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3129 if (!skb) 3130 return NULL; 3131 3132 /* Reserve room for dummy headers, this skb can pass 3133 * through good chunk of routing engine. 3134 */ 3135 skb_reset_mac_header(skb); 3136 skb_reset_network_header(skb); 3137 skb->protocol = htons(ETH_P_IP); 3138 iph = skb_put(skb, sizeof(struct iphdr)); 3139 iph->protocol = ip_proto; 3140 iph->saddr = src; 3141 iph->daddr = dst; 3142 iph->version = 0x4; 3143 iph->frag_off = 0; 3144 iph->ihl = 0x5; 3145 skb_set_transport_header(skb, skb->len); 3146 3147 switch (iph->protocol) { 3148 case IPPROTO_UDP: { 3149 struct udphdr *udph; 3150 3151 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3152 udph->source = sport; 3153 udph->dest = dport; 3154 udph->len = sizeof(struct udphdr); 3155 udph->check = 0; 3156 break; 3157 } 3158 case IPPROTO_TCP: { 3159 struct tcphdr *tcph; 3160 3161 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3162 tcph->source = sport; 3163 tcph->dest = dport; 3164 tcph->doff = sizeof(struct tcphdr) / 4; 3165 tcph->rst = 1; 3166 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3167 src, dst, 0); 3168 break; 3169 } 3170 case IPPROTO_ICMP: { 3171 struct icmphdr *icmph; 3172 3173 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3174 icmph->type = ICMP_ECHO; 3175 icmph->code = 0; 3176 } 3177 } 3178 3179 return skb; 3180 } 3181 3182 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3183 const struct nlmsghdr *nlh, 3184 struct nlattr **tb, 3185 struct netlink_ext_ack *extack) 3186 { 3187 struct rtmsg *rtm; 3188 int i, err; 3189 3190 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3191 NL_SET_ERR_MSG(extack, 3192 "ipv4: Invalid header for route get request"); 3193 return -EINVAL; 3194 } 3195 3196 if (!netlink_strict_get_check(skb)) 3197 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3198 rtm_ipv4_policy, extack); 3199 3200 rtm = nlmsg_data(nlh); 3201 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3202 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3203 rtm->rtm_table || rtm->rtm_protocol || 3204 rtm->rtm_scope || rtm->rtm_type) { 3205 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3206 return -EINVAL; 3207 } 3208 3209 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3210 RTM_F_LOOKUP_TABLE | 3211 RTM_F_FIB_MATCH)) { 3212 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3213 return -EINVAL; 3214 } 3215 3216 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3217 rtm_ipv4_policy, extack); 3218 if (err) 3219 return err; 3220 3221 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3222 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3223 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3224 return -EINVAL; 3225 } 3226 3227 for (i = 0; i <= RTA_MAX; i++) { 3228 if (!tb[i]) 3229 continue; 3230 3231 switch (i) { 3232 case RTA_IIF: 3233 case RTA_OIF: 3234 case RTA_SRC: 3235 case RTA_DST: 3236 case RTA_IP_PROTO: 3237 case RTA_SPORT: 3238 case RTA_DPORT: 3239 case RTA_MARK: 3240 case RTA_UID: 3241 break; 3242 default: 3243 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3244 return -EINVAL; 3245 } 3246 } 3247 3248 return 0; 3249 } 3250 3251 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3252 struct netlink_ext_ack *extack) 3253 { 3254 struct net *net = sock_net(in_skb->sk); 3255 struct nlattr *tb[RTA_MAX+1]; 3256 u32 table_id = RT_TABLE_MAIN; 3257 __be16 sport = 0, dport = 0; 3258 struct fib_result res = {}; 3259 u8 ip_proto = IPPROTO_UDP; 3260 struct rtable *rt = NULL; 3261 struct sk_buff *skb; 3262 struct rtmsg *rtm; 3263 struct flowi4 fl4 = {}; 3264 __be32 dst = 0; 3265 __be32 src = 0; 3266 kuid_t uid; 3267 u32 iif; 3268 int err; 3269 int mark; 3270 3271 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3272 if (err < 0) 3273 return err; 3274 3275 rtm = nlmsg_data(nlh); 3276 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3277 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3278 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3279 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3280 if (tb[RTA_UID]) 3281 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3282 else 3283 uid = (iif ? INVALID_UID : current_uid()); 3284 3285 if (tb[RTA_IP_PROTO]) { 3286 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3287 &ip_proto, AF_INET, extack); 3288 if (err) 3289 return err; 3290 } 3291 3292 if (tb[RTA_SPORT]) 3293 sport = nla_get_be16(tb[RTA_SPORT]); 3294 3295 if (tb[RTA_DPORT]) 3296 dport = nla_get_be16(tb[RTA_DPORT]); 3297 3298 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3299 if (!skb) 3300 return -ENOBUFS; 3301 3302 fl4.daddr = dst; 3303 fl4.saddr = src; 3304 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK; 3305 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3306 fl4.flowi4_mark = mark; 3307 fl4.flowi4_uid = uid; 3308 if (sport) 3309 fl4.fl4_sport = sport; 3310 if (dport) 3311 fl4.fl4_dport = dport; 3312 fl4.flowi4_proto = ip_proto; 3313 3314 rcu_read_lock(); 3315 3316 if (iif) { 3317 struct net_device *dev; 3318 3319 dev = dev_get_by_index_rcu(net, iif); 3320 if (!dev) { 3321 err = -ENODEV; 3322 goto errout_rcu; 3323 } 3324 3325 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3326 skb->dev = dev; 3327 skb->mark = mark; 3328 err = ip_route_input_rcu(skb, dst, src, 3329 rtm->rtm_tos & IPTOS_RT_MASK, dev, 3330 &res); 3331 3332 rt = skb_rtable(skb); 3333 if (err == 0 && rt->dst.error) 3334 err = -rt->dst.error; 3335 } else { 3336 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3337 skb->dev = net->loopback_dev; 3338 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3339 err = 0; 3340 if (IS_ERR(rt)) 3341 err = PTR_ERR(rt); 3342 else 3343 skb_dst_set(skb, &rt->dst); 3344 } 3345 3346 if (err) 3347 goto errout_rcu; 3348 3349 if (rtm->rtm_flags & RTM_F_NOTIFY) 3350 rt->rt_flags |= RTCF_NOTIFY; 3351 3352 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3353 table_id = res.table ? res.table->tb_id : 0; 3354 3355 /* reset skb for netlink reply msg */ 3356 skb_trim(skb, 0); 3357 skb_reset_network_header(skb); 3358 skb_reset_transport_header(skb); 3359 skb_reset_mac_header(skb); 3360 3361 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3362 struct fib_rt_info fri; 3363 3364 if (!res.fi) { 3365 err = fib_props[res.type].error; 3366 if (!err) 3367 err = -EHOSTUNREACH; 3368 goto errout_rcu; 3369 } 3370 fri.fi = res.fi; 3371 fri.tb_id = table_id; 3372 fri.dst = res.prefix; 3373 fri.dst_len = res.prefixlen; 3374 fri.tos = fl4.flowi4_tos; 3375 fri.type = rt->rt_type; 3376 fri.offload = 0; 3377 fri.trap = 0; 3378 fri.offload_failed = 0; 3379 if (res.fa_head) { 3380 struct fib_alias *fa; 3381 3382 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3383 u8 slen = 32 - fri.dst_len; 3384 3385 if (fa->fa_slen == slen && 3386 fa->tb_id == fri.tb_id && 3387 fa->fa_tos == fri.tos && 3388 fa->fa_info == res.fi && 3389 fa->fa_type == fri.type) { 3390 fri.offload = fa->offload; 3391 fri.trap = fa->trap; 3392 break; 3393 } 3394 } 3395 } 3396 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3397 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3398 } else { 3399 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3400 NETLINK_CB(in_skb).portid, 3401 nlh->nlmsg_seq, 0); 3402 } 3403 if (err < 0) 3404 goto errout_rcu; 3405 3406 rcu_read_unlock(); 3407 3408 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3409 3410 errout_free: 3411 return err; 3412 errout_rcu: 3413 rcu_read_unlock(); 3414 kfree_skb(skb); 3415 goto errout_free; 3416 } 3417 3418 void ip_rt_multicast_event(struct in_device *in_dev) 3419 { 3420 rt_cache_flush(dev_net(in_dev->dev)); 3421 } 3422 3423 #ifdef CONFIG_SYSCTL 3424 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3425 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3426 static int ip_rt_gc_elasticity __read_mostly = 8; 3427 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3428 3429 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3430 void *buffer, size_t *lenp, loff_t *ppos) 3431 { 3432 struct net *net = (struct net *)__ctl->extra1; 3433 3434 if (write) { 3435 rt_cache_flush(net); 3436 fnhe_genid_bump(net); 3437 return 0; 3438 } 3439 3440 return -EINVAL; 3441 } 3442 3443 static struct ctl_table ipv4_route_table[] = { 3444 { 3445 .procname = "gc_thresh", 3446 .data = &ipv4_dst_ops.gc_thresh, 3447 .maxlen = sizeof(int), 3448 .mode = 0644, 3449 .proc_handler = proc_dointvec, 3450 }, 3451 { 3452 .procname = "max_size", 3453 .data = &ip_rt_max_size, 3454 .maxlen = sizeof(int), 3455 .mode = 0644, 3456 .proc_handler = proc_dointvec, 3457 }, 3458 { 3459 /* Deprecated. Use gc_min_interval_ms */ 3460 3461 .procname = "gc_min_interval", 3462 .data = &ip_rt_gc_min_interval, 3463 .maxlen = sizeof(int), 3464 .mode = 0644, 3465 .proc_handler = proc_dointvec_jiffies, 3466 }, 3467 { 3468 .procname = "gc_min_interval_ms", 3469 .data = &ip_rt_gc_min_interval, 3470 .maxlen = sizeof(int), 3471 .mode = 0644, 3472 .proc_handler = proc_dointvec_ms_jiffies, 3473 }, 3474 { 3475 .procname = "gc_timeout", 3476 .data = &ip_rt_gc_timeout, 3477 .maxlen = sizeof(int), 3478 .mode = 0644, 3479 .proc_handler = proc_dointvec_jiffies, 3480 }, 3481 { 3482 .procname = "gc_interval", 3483 .data = &ip_rt_gc_interval, 3484 .maxlen = sizeof(int), 3485 .mode = 0644, 3486 .proc_handler = proc_dointvec_jiffies, 3487 }, 3488 { 3489 .procname = "redirect_load", 3490 .data = &ip_rt_redirect_load, 3491 .maxlen = sizeof(int), 3492 .mode = 0644, 3493 .proc_handler = proc_dointvec, 3494 }, 3495 { 3496 .procname = "redirect_number", 3497 .data = &ip_rt_redirect_number, 3498 .maxlen = sizeof(int), 3499 .mode = 0644, 3500 .proc_handler = proc_dointvec, 3501 }, 3502 { 3503 .procname = "redirect_silence", 3504 .data = &ip_rt_redirect_silence, 3505 .maxlen = sizeof(int), 3506 .mode = 0644, 3507 .proc_handler = proc_dointvec, 3508 }, 3509 { 3510 .procname = "error_cost", 3511 .data = &ip_rt_error_cost, 3512 .maxlen = sizeof(int), 3513 .mode = 0644, 3514 .proc_handler = proc_dointvec, 3515 }, 3516 { 3517 .procname = "error_burst", 3518 .data = &ip_rt_error_burst, 3519 .maxlen = sizeof(int), 3520 .mode = 0644, 3521 .proc_handler = proc_dointvec, 3522 }, 3523 { 3524 .procname = "gc_elasticity", 3525 .data = &ip_rt_gc_elasticity, 3526 .maxlen = sizeof(int), 3527 .mode = 0644, 3528 .proc_handler = proc_dointvec, 3529 }, 3530 { 3531 .procname = "mtu_expires", 3532 .data = &ip_rt_mtu_expires, 3533 .maxlen = sizeof(int), 3534 .mode = 0644, 3535 .proc_handler = proc_dointvec_jiffies, 3536 }, 3537 { 3538 .procname = "min_pmtu", 3539 .data = &ip_rt_min_pmtu, 3540 .maxlen = sizeof(int), 3541 .mode = 0644, 3542 .proc_handler = proc_dointvec_minmax, 3543 .extra1 = &ip_min_valid_pmtu, 3544 }, 3545 { 3546 .procname = "min_adv_mss", 3547 .data = &ip_rt_min_advmss, 3548 .maxlen = sizeof(int), 3549 .mode = 0644, 3550 .proc_handler = proc_dointvec, 3551 }, 3552 { } 3553 }; 3554 3555 static const char ipv4_route_flush_procname[] = "flush"; 3556 3557 static struct ctl_table ipv4_route_flush_table[] = { 3558 { 3559 .procname = ipv4_route_flush_procname, 3560 .maxlen = sizeof(int), 3561 .mode = 0200, 3562 .proc_handler = ipv4_sysctl_rtcache_flush, 3563 }, 3564 { }, 3565 }; 3566 3567 static __net_init int sysctl_route_net_init(struct net *net) 3568 { 3569 struct ctl_table *tbl; 3570 3571 tbl = ipv4_route_flush_table; 3572 if (!net_eq(net, &init_net)) { 3573 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3574 if (!tbl) 3575 goto err_dup; 3576 3577 /* Don't export non-whitelisted sysctls to unprivileged users */ 3578 if (net->user_ns != &init_user_ns) { 3579 if (tbl[0].procname != ipv4_route_flush_procname) 3580 tbl[0].procname = NULL; 3581 } 3582 } 3583 tbl[0].extra1 = net; 3584 3585 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3586 if (!net->ipv4.route_hdr) 3587 goto err_reg; 3588 return 0; 3589 3590 err_reg: 3591 if (tbl != ipv4_route_flush_table) 3592 kfree(tbl); 3593 err_dup: 3594 return -ENOMEM; 3595 } 3596 3597 static __net_exit void sysctl_route_net_exit(struct net *net) 3598 { 3599 struct ctl_table *tbl; 3600 3601 tbl = net->ipv4.route_hdr->ctl_table_arg; 3602 unregister_net_sysctl_table(net->ipv4.route_hdr); 3603 BUG_ON(tbl == ipv4_route_flush_table); 3604 kfree(tbl); 3605 } 3606 3607 static __net_initdata struct pernet_operations sysctl_route_ops = { 3608 .init = sysctl_route_net_init, 3609 .exit = sysctl_route_net_exit, 3610 }; 3611 #endif 3612 3613 static __net_init int rt_genid_init(struct net *net) 3614 { 3615 atomic_set(&net->ipv4.rt_genid, 0); 3616 atomic_set(&net->fnhe_genid, 0); 3617 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3618 return 0; 3619 } 3620 3621 static __net_initdata struct pernet_operations rt_genid_ops = { 3622 .init = rt_genid_init, 3623 }; 3624 3625 static int __net_init ipv4_inetpeer_init(struct net *net) 3626 { 3627 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3628 3629 if (!bp) 3630 return -ENOMEM; 3631 inet_peer_base_init(bp); 3632 net->ipv4.peers = bp; 3633 return 0; 3634 } 3635 3636 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3637 { 3638 struct inet_peer_base *bp = net->ipv4.peers; 3639 3640 net->ipv4.peers = NULL; 3641 inetpeer_invalidate_tree(bp); 3642 kfree(bp); 3643 } 3644 3645 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3646 .init = ipv4_inetpeer_init, 3647 .exit = ipv4_inetpeer_exit, 3648 }; 3649 3650 #ifdef CONFIG_IP_ROUTE_CLASSID 3651 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3652 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3653 3654 int __init ip_rt_init(void) 3655 { 3656 void *idents_hash; 3657 int cpu; 3658 3659 /* For modern hosts, this will use 2 MB of memory */ 3660 idents_hash = alloc_large_system_hash("IP idents", 3661 sizeof(*ip_idents) + sizeof(*ip_tstamps), 3662 0, 3663 16, /* one bucket per 64 KB */ 3664 HASH_ZERO, 3665 NULL, 3666 &ip_idents_mask, 3667 2048, 3668 256*1024); 3669 3670 ip_idents = idents_hash; 3671 3672 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents)); 3673 3674 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents); 3675 3676 for_each_possible_cpu(cpu) { 3677 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3678 3679 INIT_LIST_HEAD(&ul->head); 3680 spin_lock_init(&ul->lock); 3681 } 3682 #ifdef CONFIG_IP_ROUTE_CLASSID 3683 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3684 if (!ip_rt_acct) 3685 panic("IP: failed to allocate ip_rt_acct\n"); 3686 #endif 3687 3688 ipv4_dst_ops.kmem_cachep = 3689 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3690 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3691 3692 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3693 3694 if (dst_entries_init(&ipv4_dst_ops) < 0) 3695 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3696 3697 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3698 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3699 3700 ipv4_dst_ops.gc_thresh = ~0; 3701 ip_rt_max_size = INT_MAX; 3702 3703 devinet_init(); 3704 ip_fib_init(); 3705 3706 if (ip_rt_proc_init()) 3707 pr_err("Unable to create route proc files\n"); 3708 #ifdef CONFIG_XFRM 3709 xfrm_init(); 3710 xfrm4_init(); 3711 #endif 3712 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3713 RTNL_FLAG_DOIT_UNLOCKED); 3714 3715 #ifdef CONFIG_SYSCTL 3716 register_pernet_subsys(&sysctl_route_ops); 3717 #endif 3718 register_pernet_subsys(&rt_genid_ops); 3719 register_pernet_subsys(&ipv4_inetpeer_ops); 3720 return 0; 3721 } 3722 3723 #ifdef CONFIG_SYSCTL 3724 /* 3725 * We really need to sanitize the damn ipv4 init order, then all 3726 * this nonsense will go away. 3727 */ 3728 void __init ip_static_sysctl_init(void) 3729 { 3730 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3731 } 3732 #endif 3733