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/bitops.h> 65#include <linux/kernel.h> 66#include <linux/mm.h> 67#include <linux/memblock.h> 68#include <linux/socket.h> 69#include <linux/errno.h> 70#include <linux/in.h> 71#include <linux/inet.h> 72#include <linux/netdevice.h> 73#include <linux/proc_fs.h> 74#include <linux/init.h> 75#include <linux/skbuff.h> 76#include <linux/inetdevice.h> 77#include <linux/igmp.h> 78#include <linux/pkt_sched.h> 79#include <linux/mroute.h> 80#include <linux/netfilter_ipv4.h> 81#include <linux/random.h> 82#include <linux/rcupdate.h> 83#include <linux/slab.h> 84#include <linux/jhash.h> 85#include <net/dst.h> 86#include <net/dst_metadata.h> 87#include <net/inet_dscp.h> 88#include <net/net_namespace.h> 89#include <net/ip.h> 90#include <net/route.h> 91#include <net/inetpeer.h> 92#include <net/sock.h> 93#include <net/ip_fib.h> 94#include <net/nexthop.h> 95#include <net/tcp.h> 96#include <net/icmp.h> 97#include <net/xfrm.h> 98#include <net/lwtunnel.h> 99#include <net/netevent.h> 100#include <net/rtnetlink.h> 101#ifdef CONFIG_SYSCTL 102#include <linux/sysctl.h> 103#endif 104#include <net/secure_seq.h> 105#include <net/ip_tunnels.h> 106 107#include "fib_lookup.h" 108 109#define RT_FL_TOS(oldflp4) \ 110 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 111 112#define RT_GC_TIMEOUT (300*HZ) 113 114#define DEFAULT_MIN_PMTU (512 + 20 + 20) 115#define DEFAULT_MTU_EXPIRES (10 * 60 * HZ) 116#define DEFAULT_MIN_ADVMSS 256 117static int ip_rt_max_size; 118static int ip_rt_redirect_number __read_mostly = 9; 119static int ip_rt_redirect_load __read_mostly = HZ / 50; 120static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 121static int ip_rt_error_cost __read_mostly = HZ; 122static int ip_rt_error_burst __read_mostly = 5 * HZ; 123 124static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 125 126/* 127 * Interface to generic destination cache. 128 */ 129 130INDIRECT_CALLABLE_SCOPE 131struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 132static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 133INDIRECT_CALLABLE_SCOPE 134unsigned int ipv4_mtu(const struct dst_entry *dst); 135static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 136static void ipv4_link_failure(struct sk_buff *skb); 137static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 138 struct sk_buff *skb, u32 mtu, 139 bool confirm_neigh); 140static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 141 struct sk_buff *skb); 142static void ipv4_dst_destroy(struct dst_entry *dst); 143 144static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 145{ 146 WARN_ON(1); 147 return NULL; 148} 149 150static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 151 struct sk_buff *skb, 152 const void *daddr); 153static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 154 155static struct dst_ops ipv4_dst_ops = { 156 .family = AF_INET, 157 .check = ipv4_dst_check, 158 .default_advmss = ipv4_default_advmss, 159 .mtu = ipv4_mtu, 160 .cow_metrics = ipv4_cow_metrics, 161 .destroy = ipv4_dst_destroy, 162 .negative_advice = ipv4_negative_advice, 163 .link_failure = ipv4_link_failure, 164 .update_pmtu = ip_rt_update_pmtu, 165 .redirect = ip_do_redirect, 166 .local_out = __ip_local_out, 167 .neigh_lookup = ipv4_neigh_lookup, 168 .confirm_neigh = ipv4_confirm_neigh, 169}; 170 171#define ECN_OR_COST(class) TC_PRIO_##class 172 173const __u8 ip_tos2prio[16] = { 174 TC_PRIO_BESTEFFORT, 175 ECN_OR_COST(BESTEFFORT), 176 TC_PRIO_BESTEFFORT, 177 ECN_OR_COST(BESTEFFORT), 178 TC_PRIO_BULK, 179 ECN_OR_COST(BULK), 180 TC_PRIO_BULK, 181 ECN_OR_COST(BULK), 182 TC_PRIO_INTERACTIVE, 183 ECN_OR_COST(INTERACTIVE), 184 TC_PRIO_INTERACTIVE, 185 ECN_OR_COST(INTERACTIVE), 186 TC_PRIO_INTERACTIVE_BULK, 187 ECN_OR_COST(INTERACTIVE_BULK), 188 TC_PRIO_INTERACTIVE_BULK, 189 ECN_OR_COST(INTERACTIVE_BULK) 190}; 191EXPORT_SYMBOL(ip_tos2prio); 192 193static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 194#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 195 196#ifdef CONFIG_PROC_FS 197static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 198{ 199 if (*pos) 200 return NULL; 201 return SEQ_START_TOKEN; 202} 203 204static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 205{ 206 ++*pos; 207 return NULL; 208} 209 210static void rt_cache_seq_stop(struct seq_file *seq, void *v) 211{ 212} 213 214static int rt_cache_seq_show(struct seq_file *seq, void *v) 215{ 216 if (v == SEQ_START_TOKEN) 217 seq_printf(seq, "%-127s\n", 218 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 219 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 220 "HHUptod\tSpecDst"); 221 return 0; 222} 223 224static const struct seq_operations rt_cache_seq_ops = { 225 .start = rt_cache_seq_start, 226 .next = rt_cache_seq_next, 227 .stop = rt_cache_seq_stop, 228 .show = rt_cache_seq_show, 229}; 230 231static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 232{ 233 int cpu; 234 235 if (*pos == 0) 236 return SEQ_START_TOKEN; 237 238 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 239 if (!cpu_possible(cpu)) 240 continue; 241 *pos = cpu+1; 242 return &per_cpu(rt_cache_stat, cpu); 243 } 244 return NULL; 245} 246 247static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 248{ 249 int cpu; 250 251 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 252 if (!cpu_possible(cpu)) 253 continue; 254 *pos = cpu+1; 255 return &per_cpu(rt_cache_stat, cpu); 256 } 257 (*pos)++; 258 return NULL; 259 260} 261 262static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 263{ 264 265} 266 267static int rt_cpu_seq_show(struct seq_file *seq, void *v) 268{ 269 struct rt_cache_stat *st = v; 270 271 if (v == SEQ_START_TOKEN) { 272 seq_puts(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"); 273 return 0; 274 } 275 276 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x " 277 "%08x %08x %08x %08x %08x %08x " 278 "%08x %08x %08x %08x\n", 279 dst_entries_get_slow(&ipv4_dst_ops), 280 0, /* st->in_hit */ 281 st->in_slow_tot, 282 st->in_slow_mc, 283 st->in_no_route, 284 st->in_brd, 285 st->in_martian_dst, 286 st->in_martian_src, 287 288 0, /* st->out_hit */ 289 st->out_slow_tot, 290 st->out_slow_mc, 291 292 0, /* st->gc_total */ 293 0, /* st->gc_ignored */ 294 0, /* st->gc_goal_miss */ 295 0, /* st->gc_dst_overflow */ 296 0, /* st->in_hlist_search */ 297 0 /* st->out_hlist_search */ 298 ); 299 return 0; 300} 301 302static const struct seq_operations rt_cpu_seq_ops = { 303 .start = rt_cpu_seq_start, 304 .next = rt_cpu_seq_next, 305 .stop = rt_cpu_seq_stop, 306 .show = rt_cpu_seq_show, 307}; 308 309#ifdef CONFIG_IP_ROUTE_CLASSID 310static int rt_acct_proc_show(struct seq_file *m, void *v) 311{ 312 struct ip_rt_acct *dst, *src; 313 unsigned int i, j; 314 315 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 316 if (!dst) 317 return -ENOMEM; 318 319 for_each_possible_cpu(i) { 320 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 321 for (j = 0; j < 256; j++) { 322 dst[j].o_bytes += src[j].o_bytes; 323 dst[j].o_packets += src[j].o_packets; 324 dst[j].i_bytes += src[j].i_bytes; 325 dst[j].i_packets += src[j].i_packets; 326 } 327 } 328 329 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 330 kfree(dst); 331 return 0; 332} 333#endif 334 335static int __net_init ip_rt_do_proc_init(struct net *net) 336{ 337 struct proc_dir_entry *pde; 338 339 pde = proc_create_seq("rt_cache", 0444, net->proc_net, 340 &rt_cache_seq_ops); 341 if (!pde) 342 goto err1; 343 344 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat, 345 &rt_cpu_seq_ops); 346 if (!pde) 347 goto err2; 348 349#ifdef CONFIG_IP_ROUTE_CLASSID 350 pde = proc_create_single("rt_acct", 0, net->proc_net, 351 rt_acct_proc_show); 352 if (!pde) 353 goto err3; 354#endif 355 return 0; 356 357#ifdef CONFIG_IP_ROUTE_CLASSID 358err3: 359 remove_proc_entry("rt_cache", net->proc_net_stat); 360#endif 361err2: 362 remove_proc_entry("rt_cache", net->proc_net); 363err1: 364 return -ENOMEM; 365} 366 367static void __net_exit ip_rt_do_proc_exit(struct net *net) 368{ 369 remove_proc_entry("rt_cache", net->proc_net_stat); 370 remove_proc_entry("rt_cache", net->proc_net); 371#ifdef CONFIG_IP_ROUTE_CLASSID 372 remove_proc_entry("rt_acct", net->proc_net); 373#endif 374} 375 376static struct pernet_operations ip_rt_proc_ops __net_initdata = { 377 .init = ip_rt_do_proc_init, 378 .exit = ip_rt_do_proc_exit, 379}; 380 381static int __init ip_rt_proc_init(void) 382{ 383 return register_pernet_subsys(&ip_rt_proc_ops); 384} 385 386#else 387static inline int ip_rt_proc_init(void) 388{ 389 return 0; 390} 391#endif /* CONFIG_PROC_FS */ 392 393static inline bool rt_is_expired(const struct rtable *rth) 394{ 395 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 396} 397 398void rt_cache_flush(struct net *net) 399{ 400 rt_genid_bump_ipv4(net); 401} 402 403static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 404 struct sk_buff *skb, 405 const void *daddr) 406{ 407 const struct rtable *rt = container_of(dst, struct rtable, dst); 408 struct net_device *dev = dst->dev; 409 struct neighbour *n; 410 411 rcu_read_lock(); 412 413 if (likely(rt->rt_gw_family == AF_INET)) { 414 n = ip_neigh_gw4(dev, rt->rt_gw4); 415 } else if (rt->rt_gw_family == AF_INET6) { 416 n = ip_neigh_gw6(dev, &rt->rt_gw6); 417 } else { 418 __be32 pkey; 419 420 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 421 n = ip_neigh_gw4(dev, pkey); 422 } 423 424 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 425 n = NULL; 426 427 rcu_read_unlock(); 428 429 return n; 430} 431 432static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 433{ 434 const struct rtable *rt = container_of(dst, struct rtable, dst); 435 struct net_device *dev = dst->dev; 436 const __be32 *pkey = daddr; 437 438 if (rt->rt_gw_family == AF_INET) { 439 pkey = (const __be32 *)&rt->rt_gw4; 440 } else if (rt->rt_gw_family == AF_INET6) { 441 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 442 } else if (!daddr || 443 (rt->rt_flags & 444 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 445 return; 446 } 447 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 448} 449 450/* Hash tables of size 2048..262144 depending on RAM size. 451 * Each bucket uses 8 bytes. 452 */ 453static u32 ip_idents_mask __read_mostly; 454static atomic_t *ip_idents __read_mostly; 455static u32 *ip_tstamps __read_mostly; 456 457/* In order to protect privacy, we add a perturbation to identifiers 458 * if one generator is seldom used. This makes hard for an attacker 459 * to infer how many packets were sent between two points in time. 460 */ 461static u32 ip_idents_reserve(u32 hash, int segs) 462{ 463 u32 bucket, old, now = (u32)jiffies; 464 atomic_t *p_id; 465 u32 *p_tstamp; 466 u32 delta = 0; 467 468 bucket = hash & ip_idents_mask; 469 p_tstamp = ip_tstamps + bucket; 470 p_id = ip_idents + bucket; 471 old = READ_ONCE(*p_tstamp); 472 473 if (old != now && cmpxchg(p_tstamp, old, now) == old) 474 delta = get_random_u32_below(now - old); 475 476 /* If UBSAN reports an error there, please make sure your compiler 477 * supports -fno-strict-overflow before reporting it that was a bug 478 * in UBSAN, and it has been fixed in GCC-8. 479 */ 480 return atomic_add_return(segs + delta, p_id) - segs; 481} 482 483void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 484{ 485 u32 hash, id; 486 487 /* Note the following code is not safe, but this is okay. */ 488 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 489 get_random_bytes(&net->ipv4.ip_id_key, 490 sizeof(net->ipv4.ip_id_key)); 491 492 hash = siphash_3u32((__force u32)iph->daddr, 493 (__force u32)iph->saddr, 494 iph->protocol, 495 &net->ipv4.ip_id_key); 496 id = ip_idents_reserve(hash, segs); 497 iph->id = htons(id); 498} 499EXPORT_SYMBOL(__ip_select_ident); 500 501static void ip_rt_fix_tos(struct flowi4 *fl4) 502{ 503 __u8 tos = RT_FL_TOS(fl4); 504 505 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 506 if (tos & RTO_ONLINK) 507 fl4->flowi4_scope = RT_SCOPE_LINK; 508} 509 510static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 511 const struct sock *sk, const struct iphdr *iph, 512 int oif, __u8 tos, u8 prot, u32 mark, 513 int flow_flags) 514{ 515 __u8 scope = RT_SCOPE_UNIVERSE; 516 517 if (sk) { 518 oif = sk->sk_bound_dev_if; 519 mark = READ_ONCE(sk->sk_mark); 520 tos = ip_sock_rt_tos(sk); 521 scope = ip_sock_rt_scope(sk); 522 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW : 523 sk->sk_protocol; 524 } 525 526 flowi4_init_output(fl4, oif, mark, tos & IPTOS_RT_MASK, scope, 527 prot, flow_flags, iph->daddr, iph->saddr, 0, 0, 528 sock_net_uid(net, sk)); 529} 530 531static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 532 const struct sock *sk) 533{ 534 const struct net *net = dev_net(skb->dev); 535 const struct iphdr *iph = ip_hdr(skb); 536 int oif = skb->dev->ifindex; 537 u8 prot = iph->protocol; 538 u32 mark = skb->mark; 539 __u8 tos = iph->tos; 540 541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 542} 543 544static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 545{ 546 const struct inet_sock *inet = inet_sk(sk); 547 const struct ip_options_rcu *inet_opt; 548 __be32 daddr = inet->inet_daddr; 549 550 rcu_read_lock(); 551 inet_opt = rcu_dereference(inet->inet_opt); 552 if (inet_opt && inet_opt->opt.srr) 553 daddr = inet_opt->opt.faddr; 554 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark), 555 ip_sock_rt_tos(sk) & IPTOS_RT_MASK, 556 ip_sock_rt_scope(sk), 557 inet_test_bit(HDRINCL, sk) ? 558 IPPROTO_RAW : sk->sk_protocol, 559 inet_sk_flowi_flags(sk), 560 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 561 rcu_read_unlock(); 562} 563 564static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 565 const struct sk_buff *skb) 566{ 567 if (skb) 568 build_skb_flow_key(fl4, skb, sk); 569 else 570 build_sk_flow_key(fl4, sk); 571} 572 573static DEFINE_SPINLOCK(fnhe_lock); 574 575static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 576{ 577 struct rtable *rt; 578 579 rt = rcu_dereference(fnhe->fnhe_rth_input); 580 if (rt) { 581 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 582 dst_dev_put(&rt->dst); 583 dst_release(&rt->dst); 584 } 585 rt = rcu_dereference(fnhe->fnhe_rth_output); 586 if (rt) { 587 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 588 dst_dev_put(&rt->dst); 589 dst_release(&rt->dst); 590 } 591} 592 593static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash) 594{ 595 struct fib_nh_exception __rcu **fnhe_p, **oldest_p; 596 struct fib_nh_exception *fnhe, *oldest = NULL; 597 598 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) { 599 fnhe = rcu_dereference_protected(*fnhe_p, 600 lockdep_is_held(&fnhe_lock)); 601 if (!fnhe) 602 break; 603 if (!oldest || 604 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) { 605 oldest = fnhe; 606 oldest_p = fnhe_p; 607 } 608 } 609 fnhe_flush_routes(oldest); 610 *oldest_p = oldest->fnhe_next; 611 kfree_rcu(oldest, rcu); 612} 613 614static u32 fnhe_hashfun(__be32 daddr) 615{ 616 static siphash_aligned_key_t fnhe_hash_key; 617 u64 hval; 618 619 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key)); 620 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key); 621 return hash_64(hval, FNHE_HASH_SHIFT); 622} 623 624static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 625{ 626 rt->rt_pmtu = fnhe->fnhe_pmtu; 627 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 628 rt->dst.expires = fnhe->fnhe_expires; 629 630 if (fnhe->fnhe_gw) { 631 rt->rt_flags |= RTCF_REDIRECTED; 632 rt->rt_uses_gateway = 1; 633 rt->rt_gw_family = AF_INET; 634 rt->rt_gw4 = fnhe->fnhe_gw; 635 } 636} 637 638static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 639 __be32 gw, u32 pmtu, bool lock, 640 unsigned long expires) 641{ 642 struct fnhe_hash_bucket *hash; 643 struct fib_nh_exception *fnhe; 644 struct rtable *rt; 645 u32 genid, hval; 646 unsigned int i; 647 int depth; 648 649 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 650 hval = fnhe_hashfun(daddr); 651 652 spin_lock_bh(&fnhe_lock); 653 654 hash = rcu_dereference(nhc->nhc_exceptions); 655 if (!hash) { 656 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 657 if (!hash) 658 goto out_unlock; 659 rcu_assign_pointer(nhc->nhc_exceptions, hash); 660 } 661 662 hash += hval; 663 664 depth = 0; 665 for (fnhe = rcu_dereference(hash->chain); fnhe; 666 fnhe = rcu_dereference(fnhe->fnhe_next)) { 667 if (fnhe->fnhe_daddr == daddr) 668 break; 669 depth++; 670 } 671 672 if (fnhe) { 673 if (fnhe->fnhe_genid != genid) 674 fnhe->fnhe_genid = genid; 675 if (gw) 676 fnhe->fnhe_gw = gw; 677 if (pmtu) { 678 fnhe->fnhe_pmtu = pmtu; 679 fnhe->fnhe_mtu_locked = lock; 680 } 681 fnhe->fnhe_expires = max(1UL, expires); 682 /* Update all cached dsts too */ 683 rt = rcu_dereference(fnhe->fnhe_rth_input); 684 if (rt) 685 fill_route_from_fnhe(rt, fnhe); 686 rt = rcu_dereference(fnhe->fnhe_rth_output); 687 if (rt) 688 fill_route_from_fnhe(rt, fnhe); 689 } else { 690 /* Randomize max depth to avoid some side channels attacks. */ 691 int max_depth = FNHE_RECLAIM_DEPTH + 692 get_random_u32_below(FNHE_RECLAIM_DEPTH); 693 694 while (depth > max_depth) { 695 fnhe_remove_oldest(hash); 696 depth--; 697 } 698 699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 700 if (!fnhe) 701 goto out_unlock; 702 703 fnhe->fnhe_next = hash->chain; 704 705 fnhe->fnhe_genid = genid; 706 fnhe->fnhe_daddr = daddr; 707 fnhe->fnhe_gw = gw; 708 fnhe->fnhe_pmtu = pmtu; 709 fnhe->fnhe_mtu_locked = lock; 710 fnhe->fnhe_expires = max(1UL, expires); 711 712 rcu_assign_pointer(hash->chain, fnhe); 713 714 /* Exception created; mark the cached routes for the nexthop 715 * stale, so anyone caching it rechecks if this exception 716 * applies to them. 717 */ 718 rt = rcu_dereference(nhc->nhc_rth_input); 719 if (rt) 720 rt->dst.obsolete = DST_OBSOLETE_KILL; 721 722 for_each_possible_cpu(i) { 723 struct rtable __rcu **prt; 724 725 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 726 rt = rcu_dereference(*prt); 727 if (rt) 728 rt->dst.obsolete = DST_OBSOLETE_KILL; 729 } 730 } 731 732 fnhe->fnhe_stamp = jiffies; 733 734out_unlock: 735 spin_unlock_bh(&fnhe_lock); 736} 737 738static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 739 bool kill_route) 740{ 741 __be32 new_gw = icmp_hdr(skb)->un.gateway; 742 __be32 old_gw = ip_hdr(skb)->saddr; 743 struct net_device *dev = skb->dev; 744 struct in_device *in_dev; 745 struct fib_result res; 746 struct neighbour *n; 747 struct net *net; 748 749 switch (icmp_hdr(skb)->code & 7) { 750 case ICMP_REDIR_NET: 751 case ICMP_REDIR_NETTOS: 752 case ICMP_REDIR_HOST: 753 case ICMP_REDIR_HOSTTOS: 754 break; 755 756 default: 757 return; 758 } 759 760 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 761 return; 762 763 in_dev = __in_dev_get_rcu(dev); 764 if (!in_dev) 765 return; 766 767 net = dev_net(dev); 768 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 769 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 770 ipv4_is_zeronet(new_gw)) 771 goto reject_redirect; 772 773 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 774 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 775 goto reject_redirect; 776 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 777 goto reject_redirect; 778 } else { 779 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 780 goto reject_redirect; 781 } 782 783 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw); 784 if (!n) 785 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 786 if (!IS_ERR(n)) { 787 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) { 788 neigh_event_send(n, NULL); 789 } else { 790 if (fib_lookup(net, fl4, &res, 0) == 0) { 791 struct fib_nh_common *nhc; 792 793 fib_select_path(net, &res, fl4, skb); 794 nhc = FIB_RES_NHC(res); 795 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 796 0, false, 797 jiffies + ip_rt_gc_timeout); 798 } 799 if (kill_route) 800 rt->dst.obsolete = DST_OBSOLETE_KILL; 801 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 802 } 803 neigh_release(n); 804 } 805 return; 806 807reject_redirect: 808#ifdef CONFIG_IP_ROUTE_VERBOSE 809 if (IN_DEV_LOG_MARTIANS(in_dev)) { 810 const struct iphdr *iph = (const struct iphdr *) skb->data; 811 __be32 daddr = iph->daddr; 812 __be32 saddr = iph->saddr; 813 814 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 815 " Advised path = %pI4 -> %pI4\n", 816 &old_gw, dev->name, &new_gw, 817 &saddr, &daddr); 818 } 819#endif 820 ; 821} 822 823static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 824{ 825 struct rtable *rt; 826 struct flowi4 fl4; 827 const struct iphdr *iph = (const struct iphdr *) skb->data; 828 struct net *net = dev_net(skb->dev); 829 int oif = skb->dev->ifindex; 830 u8 prot = iph->protocol; 831 u32 mark = skb->mark; 832 __u8 tos = iph->tos; 833 834 rt = (struct rtable *) dst; 835 836 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 837 __ip_do_redirect(rt, skb, &fl4, true); 838} 839 840static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 841{ 842 struct rtable *rt = (struct rtable *)dst; 843 struct dst_entry *ret = dst; 844 845 if (rt) { 846 if (dst->obsolete > 0) { 847 ip_rt_put(rt); 848 ret = NULL; 849 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 850 rt->dst.expires) { 851 ip_rt_put(rt); 852 ret = NULL; 853 } 854 } 855 return ret; 856} 857 858/* 859 * Algorithm: 860 * 1. The first ip_rt_redirect_number redirects are sent 861 * with exponential backoff, then we stop sending them at all, 862 * assuming that the host ignores our redirects. 863 * 2. If we did not see packets requiring redirects 864 * during ip_rt_redirect_silence, we assume that the host 865 * forgot redirected route and start to send redirects again. 866 * 867 * This algorithm is much cheaper and more intelligent than dumb load limiting 868 * in icmp.c. 869 * 870 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 871 * and "frag. need" (breaks PMTU discovery) in icmp.c. 872 */ 873 874void ip_rt_send_redirect(struct sk_buff *skb) 875{ 876 struct rtable *rt = skb_rtable(skb); 877 struct in_device *in_dev; 878 struct inet_peer *peer; 879 struct net *net; 880 int log_martians; 881 int vif; 882 883 rcu_read_lock(); 884 in_dev = __in_dev_get_rcu(rt->dst.dev); 885 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 886 rcu_read_unlock(); 887 return; 888 } 889 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 890 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 891 rcu_read_unlock(); 892 893 net = dev_net(rt->dst.dev); 894 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 895 if (!peer) { 896 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 897 rt_nexthop(rt, ip_hdr(skb)->daddr)); 898 return; 899 } 900 901 /* No redirected packets during ip_rt_redirect_silence; 902 * reset the algorithm. 903 */ 904 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 905 peer->rate_tokens = 0; 906 peer->n_redirects = 0; 907 } 908 909 /* Too many ignored redirects; do not send anything 910 * set dst.rate_last to the last seen redirected packet. 911 */ 912 if (peer->n_redirects >= ip_rt_redirect_number) { 913 peer->rate_last = jiffies; 914 goto out_put_peer; 915 } 916 917 /* Check for load limit; set rate_last to the latest sent 918 * redirect. 919 */ 920 if (peer->n_redirects == 0 || 921 time_after(jiffies, 922 (peer->rate_last + 923 (ip_rt_redirect_load << peer->n_redirects)))) { 924 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 925 926 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 927 peer->rate_last = jiffies; 928 ++peer->n_redirects; 929 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians && 930 peer->n_redirects == ip_rt_redirect_number) 931 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 932 &ip_hdr(skb)->saddr, inet_iif(skb), 933 &ip_hdr(skb)->daddr, &gw); 934 } 935out_put_peer: 936 inet_putpeer(peer); 937} 938 939static int ip_error(struct sk_buff *skb) 940{ 941 struct rtable *rt = skb_rtable(skb); 942 struct net_device *dev = skb->dev; 943 struct in_device *in_dev; 944 struct inet_peer *peer; 945 unsigned long now; 946 struct net *net; 947 SKB_DR(reason); 948 bool send; 949 int code; 950 951 if (netif_is_l3_master(skb->dev)) { 952 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 953 if (!dev) 954 goto out; 955 } 956 957 in_dev = __in_dev_get_rcu(dev); 958 959 /* IP on this device is disabled. */ 960 if (!in_dev) 961 goto out; 962 963 net = dev_net(rt->dst.dev); 964 if (!IN_DEV_FORWARD(in_dev)) { 965 switch (rt->dst.error) { 966 case EHOSTUNREACH: 967 SKB_DR_SET(reason, IP_INADDRERRORS); 968 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 969 break; 970 971 case ENETUNREACH: 972 SKB_DR_SET(reason, IP_INNOROUTES); 973 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 974 break; 975 } 976 goto out; 977 } 978 979 switch (rt->dst.error) { 980 case EINVAL: 981 default: 982 goto out; 983 case EHOSTUNREACH: 984 code = ICMP_HOST_UNREACH; 985 break; 986 case ENETUNREACH: 987 code = ICMP_NET_UNREACH; 988 SKB_DR_SET(reason, IP_INNOROUTES); 989 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 990 break; 991 case EACCES: 992 code = ICMP_PKT_FILTERED; 993 break; 994 } 995 996 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 997 l3mdev_master_ifindex(skb->dev), 1); 998 999 send = true; 1000 if (peer) { 1001 now = jiffies; 1002 peer->rate_tokens += now - peer->rate_last; 1003 if (peer->rate_tokens > ip_rt_error_burst) 1004 peer->rate_tokens = ip_rt_error_burst; 1005 peer->rate_last = now; 1006 if (peer->rate_tokens >= ip_rt_error_cost) 1007 peer->rate_tokens -= ip_rt_error_cost; 1008 else 1009 send = false; 1010 inet_putpeer(peer); 1011 } 1012 if (send) 1013 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1014 1015out: kfree_skb_reason(skb, reason); 1016 return 0; 1017} 1018 1019static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1020{ 1021 struct dst_entry *dst = &rt->dst; 1022 struct net *net = dev_net(dst->dev); 1023 struct fib_result res; 1024 bool lock = false; 1025 u32 old_mtu; 1026 1027 if (ip_mtu_locked(dst)) 1028 return; 1029 1030 old_mtu = ipv4_mtu(dst); 1031 if (old_mtu < mtu) 1032 return; 1033 1034 if (mtu < net->ipv4.ip_rt_min_pmtu) { 1035 lock = true; 1036 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu); 1037 } 1038 1039 if (rt->rt_pmtu == mtu && !lock && 1040 time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2)) 1041 return; 1042 1043 rcu_read_lock(); 1044 if (fib_lookup(net, fl4, &res, 0) == 0) { 1045 struct fib_nh_common *nhc; 1046 1047 fib_select_path(net, &res, fl4, NULL); 1048 nhc = FIB_RES_NHC(res); 1049 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1050 jiffies + net->ipv4.ip_rt_mtu_expires); 1051 } 1052 rcu_read_unlock(); 1053} 1054 1055static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1056 struct sk_buff *skb, u32 mtu, 1057 bool confirm_neigh) 1058{ 1059 struct rtable *rt = (struct rtable *) dst; 1060 struct flowi4 fl4; 1061 1062 ip_rt_build_flow_key(&fl4, sk, skb); 1063 1064 /* Don't make lookup fail for bridged encapsulations */ 1065 if (skb && netif_is_any_bridge_port(skb->dev)) 1066 fl4.flowi4_oif = 0; 1067 1068 __ip_rt_update_pmtu(rt, &fl4, mtu); 1069} 1070 1071void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1072 int oif, u8 protocol) 1073{ 1074 const struct iphdr *iph = (const struct iphdr *)skb->data; 1075 struct flowi4 fl4; 1076 struct rtable *rt; 1077 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1078 1079 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark, 1080 0); 1081 rt = __ip_route_output_key(net, &fl4); 1082 if (!IS_ERR(rt)) { 1083 __ip_rt_update_pmtu(rt, &fl4, mtu); 1084 ip_rt_put(rt); 1085 } 1086} 1087EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1088 1089static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1090{ 1091 const struct iphdr *iph = (const struct iphdr *)skb->data; 1092 struct flowi4 fl4; 1093 struct rtable *rt; 1094 1095 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1096 1097 if (!fl4.flowi4_mark) 1098 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1099 1100 rt = __ip_route_output_key(sock_net(sk), &fl4); 1101 if (!IS_ERR(rt)) { 1102 __ip_rt_update_pmtu(rt, &fl4, mtu); 1103 ip_rt_put(rt); 1104 } 1105} 1106 1107void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1108{ 1109 const struct iphdr *iph = (const struct iphdr *)skb->data; 1110 struct flowi4 fl4; 1111 struct rtable *rt; 1112 struct dst_entry *odst = NULL; 1113 bool new = false; 1114 struct net *net = sock_net(sk); 1115 1116 bh_lock_sock(sk); 1117 1118 if (!ip_sk_accept_pmtu(sk)) 1119 goto out; 1120 1121 odst = sk_dst_get(sk); 1122 1123 if (sock_owned_by_user(sk) || !odst) { 1124 __ipv4_sk_update_pmtu(skb, sk, mtu); 1125 goto out; 1126 } 1127 1128 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1129 1130 rt = (struct rtable *)odst; 1131 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1132 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1133 if (IS_ERR(rt)) 1134 goto out; 1135 1136 new = true; 1137 } 1138 1139 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu); 1140 1141 if (!dst_check(&rt->dst, 0)) { 1142 if (new) 1143 dst_release(&rt->dst); 1144 1145 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1146 if (IS_ERR(rt)) 1147 goto out; 1148 1149 new = true; 1150 } 1151 1152 if (new) 1153 sk_dst_set(sk, &rt->dst); 1154 1155out: 1156 bh_unlock_sock(sk); 1157 dst_release(odst); 1158} 1159EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1160 1161void ipv4_redirect(struct sk_buff *skb, struct net *net, 1162 int oif, u8 protocol) 1163{ 1164 const struct iphdr *iph = (const struct iphdr *)skb->data; 1165 struct flowi4 fl4; 1166 struct rtable *rt; 1167 1168 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0); 1169 rt = __ip_route_output_key(net, &fl4); 1170 if (!IS_ERR(rt)) { 1171 __ip_do_redirect(rt, skb, &fl4, false); 1172 ip_rt_put(rt); 1173 } 1174} 1175EXPORT_SYMBOL_GPL(ipv4_redirect); 1176 1177void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1178{ 1179 const struct iphdr *iph = (const struct iphdr *)skb->data; 1180 struct flowi4 fl4; 1181 struct rtable *rt; 1182 struct net *net = sock_net(sk); 1183 1184 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1185 rt = __ip_route_output_key(net, &fl4); 1186 if (!IS_ERR(rt)) { 1187 __ip_do_redirect(rt, skb, &fl4, false); 1188 ip_rt_put(rt); 1189 } 1190} 1191EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1192 1193INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst, 1194 u32 cookie) 1195{ 1196 struct rtable *rt = (struct rtable *) dst; 1197 1198 /* All IPV4 dsts are created with ->obsolete set to the value 1199 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1200 * into this function always. 1201 * 1202 * When a PMTU/redirect information update invalidates a route, 1203 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1204 * DST_OBSOLETE_DEAD. 1205 */ 1206 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1207 return NULL; 1208 return dst; 1209} 1210EXPORT_INDIRECT_CALLABLE(ipv4_dst_check); 1211 1212static void ipv4_send_dest_unreach(struct sk_buff *skb) 1213{ 1214 struct net_device *dev; 1215 struct ip_options opt; 1216 int res; 1217 1218 /* Recompile ip options since IPCB may not be valid anymore. 1219 * Also check we have a reasonable ipv4 header. 1220 */ 1221 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1222 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1223 return; 1224 1225 memset(&opt, 0, sizeof(opt)); 1226 if (ip_hdr(skb)->ihl > 5) { 1227 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1228 return; 1229 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1230 1231 rcu_read_lock(); 1232 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev; 1233 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL); 1234 rcu_read_unlock(); 1235 1236 if (res) 1237 return; 1238 } 1239 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1240} 1241 1242static void ipv4_link_failure(struct sk_buff *skb) 1243{ 1244 struct rtable *rt; 1245 1246 ipv4_send_dest_unreach(skb); 1247 1248 rt = skb_rtable(skb); 1249 if (rt) 1250 dst_set_expires(&rt->dst, 0); 1251} 1252 1253static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1254{ 1255 pr_debug("%s: %pI4 -> %pI4, %s\n", 1256 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1257 skb->dev ? skb->dev->name : "?"); 1258 kfree_skb(skb); 1259 WARN_ON(1); 1260 return 0; 1261} 1262 1263/* 1264 * We do not cache source address of outgoing interface, 1265 * because it is used only by IP RR, TS and SRR options, 1266 * so that it out of fast path. 1267 * 1268 * BTW remember: "addr" is allowed to be not aligned 1269 * in IP options! 1270 */ 1271 1272void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1273{ 1274 __be32 src; 1275 1276 if (rt_is_output_route(rt)) 1277 src = ip_hdr(skb)->saddr; 1278 else { 1279 struct fib_result res; 1280 struct iphdr *iph = ip_hdr(skb); 1281 struct flowi4 fl4 = { 1282 .daddr = iph->daddr, 1283 .saddr = iph->saddr, 1284 .flowi4_tos = RT_TOS(iph->tos), 1285 .flowi4_oif = rt->dst.dev->ifindex, 1286 .flowi4_iif = skb->dev->ifindex, 1287 .flowi4_mark = skb->mark, 1288 }; 1289 1290 rcu_read_lock(); 1291 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1292 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1293 else 1294 src = inet_select_addr(rt->dst.dev, 1295 rt_nexthop(rt, iph->daddr), 1296 RT_SCOPE_UNIVERSE); 1297 rcu_read_unlock(); 1298 } 1299 memcpy(addr, &src, 4); 1300} 1301 1302#ifdef CONFIG_IP_ROUTE_CLASSID 1303static void set_class_tag(struct rtable *rt, u32 tag) 1304{ 1305 if (!(rt->dst.tclassid & 0xFFFF)) 1306 rt->dst.tclassid |= tag & 0xFFFF; 1307 if (!(rt->dst.tclassid & 0xFFFF0000)) 1308 rt->dst.tclassid |= tag & 0xFFFF0000; 1309} 1310#endif 1311 1312static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1313{ 1314 struct net *net = dev_net(dst->dev); 1315 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1316 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1317 net->ipv4.ip_rt_min_advmss); 1318 1319 return min(advmss, IPV4_MAX_PMTU - header_size); 1320} 1321 1322INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst) 1323{ 1324 return ip_dst_mtu_maybe_forward(dst, false); 1325} 1326EXPORT_INDIRECT_CALLABLE(ipv4_mtu); 1327 1328static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1329{ 1330 struct fnhe_hash_bucket *hash; 1331 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1332 u32 hval = fnhe_hashfun(daddr); 1333 1334 spin_lock_bh(&fnhe_lock); 1335 1336 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1337 lockdep_is_held(&fnhe_lock)); 1338 hash += hval; 1339 1340 fnhe_p = &hash->chain; 1341 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1342 while (fnhe) { 1343 if (fnhe->fnhe_daddr == daddr) { 1344 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1345 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1346 /* set fnhe_daddr to 0 to ensure it won't bind with 1347 * new dsts in rt_bind_exception(). 1348 */ 1349 fnhe->fnhe_daddr = 0; 1350 fnhe_flush_routes(fnhe); 1351 kfree_rcu(fnhe, rcu); 1352 break; 1353 } 1354 fnhe_p = &fnhe->fnhe_next; 1355 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1356 lockdep_is_held(&fnhe_lock)); 1357 } 1358 1359 spin_unlock_bh(&fnhe_lock); 1360} 1361 1362static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1363 __be32 daddr) 1364{ 1365 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1366 struct fib_nh_exception *fnhe; 1367 u32 hval; 1368 1369 if (!hash) 1370 return NULL; 1371 1372 hval = fnhe_hashfun(daddr); 1373 1374 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1375 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1376 if (fnhe->fnhe_daddr == daddr) { 1377 if (fnhe->fnhe_expires && 1378 time_after(jiffies, fnhe->fnhe_expires)) { 1379 ip_del_fnhe(nhc, daddr); 1380 break; 1381 } 1382 return fnhe; 1383 } 1384 } 1385 return NULL; 1386} 1387 1388/* MTU selection: 1389 * 1. mtu on route is locked - use it 1390 * 2. mtu from nexthop exception 1391 * 3. mtu from egress device 1392 */ 1393 1394u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1395{ 1396 struct fib_nh_common *nhc = res->nhc; 1397 struct net_device *dev = nhc->nhc_dev; 1398 struct fib_info *fi = res->fi; 1399 u32 mtu = 0; 1400 1401 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) || 1402 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1403 mtu = fi->fib_mtu; 1404 1405 if (likely(!mtu)) { 1406 struct fib_nh_exception *fnhe; 1407 1408 fnhe = find_exception(nhc, daddr); 1409 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1410 mtu = fnhe->fnhe_pmtu; 1411 } 1412 1413 if (likely(!mtu)) 1414 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1415 1416 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1417} 1418 1419static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1420 __be32 daddr, const bool do_cache) 1421{ 1422 bool ret = false; 1423 1424 spin_lock_bh(&fnhe_lock); 1425 1426 if (daddr == fnhe->fnhe_daddr) { 1427 struct rtable __rcu **porig; 1428 struct rtable *orig; 1429 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1430 1431 if (rt_is_input_route(rt)) 1432 porig = &fnhe->fnhe_rth_input; 1433 else 1434 porig = &fnhe->fnhe_rth_output; 1435 orig = rcu_dereference(*porig); 1436 1437 if (fnhe->fnhe_genid != genid) { 1438 fnhe->fnhe_genid = genid; 1439 fnhe->fnhe_gw = 0; 1440 fnhe->fnhe_pmtu = 0; 1441 fnhe->fnhe_expires = 0; 1442 fnhe->fnhe_mtu_locked = false; 1443 fnhe_flush_routes(fnhe); 1444 orig = NULL; 1445 } 1446 fill_route_from_fnhe(rt, fnhe); 1447 if (!rt->rt_gw4) { 1448 rt->rt_gw4 = daddr; 1449 rt->rt_gw_family = AF_INET; 1450 } 1451 1452 if (do_cache) { 1453 dst_hold(&rt->dst); 1454 rcu_assign_pointer(*porig, rt); 1455 if (orig) { 1456 dst_dev_put(&orig->dst); 1457 dst_release(&orig->dst); 1458 } 1459 ret = true; 1460 } 1461 1462 fnhe->fnhe_stamp = jiffies; 1463 } 1464 spin_unlock_bh(&fnhe_lock); 1465 1466 return ret; 1467} 1468 1469static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1470{ 1471 struct rtable *orig, *prev, **p; 1472 bool ret = true; 1473 1474 if (rt_is_input_route(rt)) { 1475 p = (struct rtable **)&nhc->nhc_rth_input; 1476 } else { 1477 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1478 } 1479 orig = *p; 1480 1481 /* hold dst before doing cmpxchg() to avoid race condition 1482 * on this dst 1483 */ 1484 dst_hold(&rt->dst); 1485 prev = cmpxchg(p, orig, rt); 1486 if (prev == orig) { 1487 if (orig) { 1488 rt_add_uncached_list(orig); 1489 dst_release(&orig->dst); 1490 } 1491 } else { 1492 dst_release(&rt->dst); 1493 ret = false; 1494 } 1495 1496 return ret; 1497} 1498 1499struct uncached_list { 1500 spinlock_t lock; 1501 struct list_head head; 1502 struct list_head quarantine; 1503}; 1504 1505static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1506 1507void rt_add_uncached_list(struct rtable *rt) 1508{ 1509 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1510 1511 rt->dst.rt_uncached_list = ul; 1512 1513 spin_lock_bh(&ul->lock); 1514 list_add_tail(&rt->dst.rt_uncached, &ul->head); 1515 spin_unlock_bh(&ul->lock); 1516} 1517 1518void rt_del_uncached_list(struct rtable *rt) 1519{ 1520 if (!list_empty(&rt->dst.rt_uncached)) { 1521 struct uncached_list *ul = rt->dst.rt_uncached_list; 1522 1523 spin_lock_bh(&ul->lock); 1524 list_del_init(&rt->dst.rt_uncached); 1525 spin_unlock_bh(&ul->lock); 1526 } 1527} 1528 1529static void ipv4_dst_destroy(struct dst_entry *dst) 1530{ 1531 struct rtable *rt = (struct rtable *)dst; 1532 1533 ip_dst_metrics_put(dst); 1534 rt_del_uncached_list(rt); 1535} 1536 1537void rt_flush_dev(struct net_device *dev) 1538{ 1539 struct rtable *rt, *safe; 1540 int cpu; 1541 1542 for_each_possible_cpu(cpu) { 1543 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1544 1545 if (list_empty(&ul->head)) 1546 continue; 1547 1548 spin_lock_bh(&ul->lock); 1549 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) { 1550 if (rt->dst.dev != dev) 1551 continue; 1552 rt->dst.dev = blackhole_netdev; 1553 netdev_ref_replace(dev, blackhole_netdev, 1554 &rt->dst.dev_tracker, GFP_ATOMIC); 1555 list_move(&rt->dst.rt_uncached, &ul->quarantine); 1556 } 1557 spin_unlock_bh(&ul->lock); 1558 } 1559} 1560 1561static bool rt_cache_valid(const struct rtable *rt) 1562{ 1563 return rt && 1564 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1565 !rt_is_expired(rt); 1566} 1567 1568static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1569 const struct fib_result *res, 1570 struct fib_nh_exception *fnhe, 1571 struct fib_info *fi, u16 type, u32 itag, 1572 const bool do_cache) 1573{ 1574 bool cached = false; 1575 1576 if (fi) { 1577 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1578 1579 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1580 rt->rt_uses_gateway = 1; 1581 rt->rt_gw_family = nhc->nhc_gw_family; 1582 /* only INET and INET6 are supported */ 1583 if (likely(nhc->nhc_gw_family == AF_INET)) 1584 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1585 else 1586 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1587 } 1588 1589 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1590 1591#ifdef CONFIG_IP_ROUTE_CLASSID 1592 if (nhc->nhc_family == AF_INET) { 1593 struct fib_nh *nh; 1594 1595 nh = container_of(nhc, struct fib_nh, nh_common); 1596 rt->dst.tclassid = nh->nh_tclassid; 1597 } 1598#endif 1599 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1600 if (unlikely(fnhe)) 1601 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1602 else if (do_cache) 1603 cached = rt_cache_route(nhc, rt); 1604 if (unlikely(!cached)) { 1605 /* Routes we intend to cache in nexthop exception or 1606 * FIB nexthop have the DST_NOCACHE bit clear. 1607 * However, if we are unsuccessful at storing this 1608 * route into the cache we really need to set it. 1609 */ 1610 if (!rt->rt_gw4) { 1611 rt->rt_gw_family = AF_INET; 1612 rt->rt_gw4 = daddr; 1613 } 1614 rt_add_uncached_list(rt); 1615 } 1616 } else 1617 rt_add_uncached_list(rt); 1618 1619#ifdef CONFIG_IP_ROUTE_CLASSID 1620#ifdef CONFIG_IP_MULTIPLE_TABLES 1621 set_class_tag(rt, res->tclassid); 1622#endif 1623 set_class_tag(rt, itag); 1624#endif 1625} 1626 1627struct rtable *rt_dst_alloc(struct net_device *dev, 1628 unsigned int flags, u16 type, 1629 bool noxfrm) 1630{ 1631 struct rtable *rt; 1632 1633 rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK, 1634 (noxfrm ? DST_NOXFRM : 0)); 1635 1636 if (rt) { 1637 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1638 rt->rt_flags = flags; 1639 rt->rt_type = type; 1640 rt->rt_is_input = 0; 1641 rt->rt_iif = 0; 1642 rt->rt_pmtu = 0; 1643 rt->rt_mtu_locked = 0; 1644 rt->rt_uses_gateway = 0; 1645 rt->rt_gw_family = 0; 1646 rt->rt_gw4 = 0; 1647 1648 rt->dst.output = ip_output; 1649 if (flags & RTCF_LOCAL) 1650 rt->dst.input = ip_local_deliver; 1651 } 1652 1653 return rt; 1654} 1655EXPORT_SYMBOL(rt_dst_alloc); 1656 1657struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1658{ 1659 struct rtable *new_rt; 1660 1661 new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK, 1662 rt->dst.flags); 1663 1664 if (new_rt) { 1665 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1666 new_rt->rt_flags = rt->rt_flags; 1667 new_rt->rt_type = rt->rt_type; 1668 new_rt->rt_is_input = rt->rt_is_input; 1669 new_rt->rt_iif = rt->rt_iif; 1670 new_rt->rt_pmtu = rt->rt_pmtu; 1671 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1672 new_rt->rt_gw_family = rt->rt_gw_family; 1673 if (rt->rt_gw_family == AF_INET) 1674 new_rt->rt_gw4 = rt->rt_gw4; 1675 else if (rt->rt_gw_family == AF_INET6) 1676 new_rt->rt_gw6 = rt->rt_gw6; 1677 1678 new_rt->dst.input = rt->dst.input; 1679 new_rt->dst.output = rt->dst.output; 1680 new_rt->dst.error = rt->dst.error; 1681 new_rt->dst.lastuse = jiffies; 1682 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1683 } 1684 return new_rt; 1685} 1686EXPORT_SYMBOL(rt_dst_clone); 1687 1688/* called in rcu_read_lock() section */ 1689int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1690 u8 tos, struct net_device *dev, 1691 struct in_device *in_dev, u32 *itag) 1692{ 1693 int err; 1694 1695 /* Primary sanity checks. */ 1696 if (!in_dev) 1697 return -EINVAL; 1698 1699 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1700 skb->protocol != htons(ETH_P_IP)) 1701 return -EINVAL; 1702 1703 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1704 return -EINVAL; 1705 1706 if (ipv4_is_zeronet(saddr)) { 1707 if (!ipv4_is_local_multicast(daddr) && 1708 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1709 return -EINVAL; 1710 } else { 1711 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1712 in_dev, itag); 1713 if (err < 0) 1714 return err; 1715 } 1716 return 0; 1717} 1718 1719/* called in rcu_read_lock() section */ 1720static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1721 u8 tos, struct net_device *dev, int our) 1722{ 1723 struct in_device *in_dev = __in_dev_get_rcu(dev); 1724 unsigned int flags = RTCF_MULTICAST; 1725 struct rtable *rth; 1726 u32 itag = 0; 1727 int err; 1728 1729 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1730 if (err) 1731 return err; 1732 1733 if (our) 1734 flags |= RTCF_LOCAL; 1735 1736 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 1737 IPCB(skb)->flags |= IPSKB_NOPOLICY; 1738 1739 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1740 false); 1741 if (!rth) 1742 return -ENOBUFS; 1743 1744#ifdef CONFIG_IP_ROUTE_CLASSID 1745 rth->dst.tclassid = itag; 1746#endif 1747 rth->dst.output = ip_rt_bug; 1748 rth->rt_is_input= 1; 1749 1750#ifdef CONFIG_IP_MROUTE 1751 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1752 rth->dst.input = ip_mr_input; 1753#endif 1754 RT_CACHE_STAT_INC(in_slow_mc); 1755 1756 skb_dst_drop(skb); 1757 skb_dst_set(skb, &rth->dst); 1758 return 0; 1759} 1760 1761 1762static void ip_handle_martian_source(struct net_device *dev, 1763 struct in_device *in_dev, 1764 struct sk_buff *skb, 1765 __be32 daddr, 1766 __be32 saddr) 1767{ 1768 RT_CACHE_STAT_INC(in_martian_src); 1769#ifdef CONFIG_IP_ROUTE_VERBOSE 1770 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1771 /* 1772 * RFC1812 recommendation, if source is martian, 1773 * the only hint is MAC header. 1774 */ 1775 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1776 &daddr, &saddr, dev->name); 1777 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1778 print_hex_dump(KERN_WARNING, "ll header: ", 1779 DUMP_PREFIX_OFFSET, 16, 1, 1780 skb_mac_header(skb), 1781 dev->hard_header_len, false); 1782 } 1783 } 1784#endif 1785} 1786 1787/* called in rcu_read_lock() section */ 1788static int __mkroute_input(struct sk_buff *skb, 1789 const struct fib_result *res, 1790 struct in_device *in_dev, 1791 __be32 daddr, __be32 saddr, u32 tos) 1792{ 1793 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1794 struct net_device *dev = nhc->nhc_dev; 1795 struct fib_nh_exception *fnhe; 1796 struct rtable *rth; 1797 int err; 1798 struct in_device *out_dev; 1799 bool do_cache; 1800 u32 itag = 0; 1801 1802 /* get a working reference to the output device */ 1803 out_dev = __in_dev_get_rcu(dev); 1804 if (!out_dev) { 1805 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1806 return -EINVAL; 1807 } 1808 1809 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1810 in_dev->dev, in_dev, &itag); 1811 if (err < 0) { 1812 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1813 saddr); 1814 1815 goto cleanup; 1816 } 1817 1818 do_cache = res->fi && !itag; 1819 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1820 skb->protocol == htons(ETH_P_IP)) { 1821 __be32 gw; 1822 1823 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1824 if (IN_DEV_SHARED_MEDIA(out_dev) || 1825 inet_addr_onlink(out_dev, saddr, gw)) 1826 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1827 } 1828 1829 if (skb->protocol != htons(ETH_P_IP)) { 1830 /* Not IP (i.e. ARP). Do not create route, if it is 1831 * invalid for proxy arp. DNAT routes are always valid. 1832 * 1833 * Proxy arp feature have been extended to allow, ARP 1834 * replies back to the same interface, to support 1835 * Private VLAN switch technologies. See arp.c. 1836 */ 1837 if (out_dev == in_dev && 1838 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1839 err = -EINVAL; 1840 goto cleanup; 1841 } 1842 } 1843 1844 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 1845 IPCB(skb)->flags |= IPSKB_NOPOLICY; 1846 1847 fnhe = find_exception(nhc, daddr); 1848 if (do_cache) { 1849 if (fnhe) 1850 rth = rcu_dereference(fnhe->fnhe_rth_input); 1851 else 1852 rth = rcu_dereference(nhc->nhc_rth_input); 1853 if (rt_cache_valid(rth)) { 1854 skb_dst_set_noref(skb, &rth->dst); 1855 goto out; 1856 } 1857 } 1858 1859 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1860 IN_DEV_ORCONF(out_dev, NOXFRM)); 1861 if (!rth) { 1862 err = -ENOBUFS; 1863 goto cleanup; 1864 } 1865 1866 rth->rt_is_input = 1; 1867 RT_CACHE_STAT_INC(in_slow_tot); 1868 1869 rth->dst.input = ip_forward; 1870 1871 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1872 do_cache); 1873 lwtunnel_set_redirect(&rth->dst); 1874 skb_dst_set(skb, &rth->dst); 1875out: 1876 err = 0; 1877 cleanup: 1878 return err; 1879} 1880 1881#ifdef CONFIG_IP_ROUTE_MULTIPATH 1882/* To make ICMP packets follow the right flow, the multipath hash is 1883 * calculated from the inner IP addresses. 1884 */ 1885static void ip_multipath_l3_keys(const struct sk_buff *skb, 1886 struct flow_keys *hash_keys) 1887{ 1888 const struct iphdr *outer_iph = ip_hdr(skb); 1889 const struct iphdr *key_iph = outer_iph; 1890 const struct iphdr *inner_iph; 1891 const struct icmphdr *icmph; 1892 struct iphdr _inner_iph; 1893 struct icmphdr _icmph; 1894 1895 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1896 goto out; 1897 1898 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1899 goto out; 1900 1901 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1902 &_icmph); 1903 if (!icmph) 1904 goto out; 1905 1906 if (!icmp_is_err(icmph->type)) 1907 goto out; 1908 1909 inner_iph = skb_header_pointer(skb, 1910 outer_iph->ihl * 4 + sizeof(_icmph), 1911 sizeof(_inner_iph), &_inner_iph); 1912 if (!inner_iph) 1913 goto out; 1914 1915 key_iph = inner_iph; 1916out: 1917 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1918 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1919} 1920 1921static u32 fib_multipath_custom_hash_outer(const struct net *net, 1922 const struct sk_buff *skb, 1923 bool *p_has_inner) 1924{ 1925 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 1926 struct flow_keys keys, hash_keys; 1927 1928 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 1929 return 0; 1930 1931 memset(&hash_keys, 0, sizeof(hash_keys)); 1932 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP); 1933 1934 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1935 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 1936 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1937 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 1938 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1939 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 1940 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1941 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) 1942 hash_keys.ports.src = keys.ports.src; 1943 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 1944 hash_keys.ports.dst = keys.ports.dst; 1945 1946 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION); 1947 return flow_hash_from_keys(&hash_keys); 1948} 1949 1950static u32 fib_multipath_custom_hash_inner(const struct net *net, 1951 const struct sk_buff *skb, 1952 bool has_inner) 1953{ 1954 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 1955 struct flow_keys keys, hash_keys; 1956 1957 /* We assume the packet carries an encapsulation, but if none was 1958 * encountered during dissection of the outer flow, then there is no 1959 * point in calling the flow dissector again. 1960 */ 1961 if (!has_inner) 1962 return 0; 1963 1964 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK)) 1965 return 0; 1966 1967 memset(&hash_keys, 0, sizeof(hash_keys)); 1968 skb_flow_dissect_flow_keys(skb, &keys, 0); 1969 1970 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION)) 1971 return 0; 1972 1973 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1974 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1975 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 1976 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1977 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1981 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 1982 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1983 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 1984 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1985 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL) 1986 hash_keys.tags.flow_label = keys.tags.flow_label; 1987 } 1988 1989 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO) 1990 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1991 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT) 1992 hash_keys.ports.src = keys.ports.src; 1993 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT) 1994 hash_keys.ports.dst = keys.ports.dst; 1995 1996 return flow_hash_from_keys(&hash_keys); 1997} 1998 1999static u32 fib_multipath_custom_hash_skb(const struct net *net, 2000 const struct sk_buff *skb) 2001{ 2002 u32 mhash, mhash_inner; 2003 bool has_inner = true; 2004 2005 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner); 2006 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner); 2007 2008 return jhash_2words(mhash, mhash_inner, 0); 2009} 2010 2011static u32 fib_multipath_custom_hash_fl4(const struct net *net, 2012 const struct flowi4 *fl4) 2013{ 2014 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 2015 struct flow_keys hash_keys; 2016 2017 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 2018 return 0; 2019 2020 memset(&hash_keys, 0, sizeof(hash_keys)); 2021 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2022 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 2023 hash_keys.addrs.v4addrs.src = fl4->saddr; 2024 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 2025 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2026 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 2027 hash_keys.basic.ip_proto = fl4->flowi4_proto; 2028 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) 2029 hash_keys.ports.src = fl4->fl4_sport; 2030 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 2031 hash_keys.ports.dst = fl4->fl4_dport; 2032 2033 return flow_hash_from_keys(&hash_keys); 2034} 2035 2036/* if skb is set it will be used and fl4 can be NULL */ 2037int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 2038 const struct sk_buff *skb, struct flow_keys *flkeys) 2039{ 2040 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 2041 struct flow_keys hash_keys; 2042 u32 mhash = 0; 2043 2044 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) { 2045 case 0: 2046 memset(&hash_keys, 0, sizeof(hash_keys)); 2047 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2048 if (skb) { 2049 ip_multipath_l3_keys(skb, &hash_keys); 2050 } else { 2051 hash_keys.addrs.v4addrs.src = fl4->saddr; 2052 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2053 } 2054 mhash = flow_hash_from_keys(&hash_keys); 2055 break; 2056 case 1: 2057 /* skb is currently provided only when forwarding */ 2058 if (skb) { 2059 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 2060 struct flow_keys keys; 2061 2062 /* short-circuit if we already have L4 hash present */ 2063 if (skb->l4_hash) 2064 return skb_get_hash_raw(skb) >> 1; 2065 2066 memset(&hash_keys, 0, sizeof(hash_keys)); 2067 2068 if (!flkeys) { 2069 skb_flow_dissect_flow_keys(skb, &keys, flag); 2070 flkeys = &keys; 2071 } 2072 2073 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2074 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 2075 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 2076 hash_keys.ports.src = flkeys->ports.src; 2077 hash_keys.ports.dst = flkeys->ports.dst; 2078 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 2079 } else { 2080 memset(&hash_keys, 0, sizeof(hash_keys)); 2081 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2082 hash_keys.addrs.v4addrs.src = fl4->saddr; 2083 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2084 hash_keys.ports.src = fl4->fl4_sport; 2085 hash_keys.ports.dst = fl4->fl4_dport; 2086 hash_keys.basic.ip_proto = fl4->flowi4_proto; 2087 } 2088 mhash = flow_hash_from_keys(&hash_keys); 2089 break; 2090 case 2: 2091 memset(&hash_keys, 0, sizeof(hash_keys)); 2092 /* skb is currently provided only when forwarding */ 2093 if (skb) { 2094 struct flow_keys keys; 2095 2096 skb_flow_dissect_flow_keys(skb, &keys, 0); 2097 /* Inner can be v4 or v6 */ 2098 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 2099 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2100 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 2101 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 2102 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 2103 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 2104 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 2105 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 2106 hash_keys.tags.flow_label = keys.tags.flow_label; 2107 hash_keys.basic.ip_proto = keys.basic.ip_proto; 2108 } else { 2109 /* Same as case 0 */ 2110 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2111 ip_multipath_l3_keys(skb, &hash_keys); 2112 } 2113 } else { 2114 /* Same as case 0 */ 2115 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2116 hash_keys.addrs.v4addrs.src = fl4->saddr; 2117 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2118 } 2119 mhash = flow_hash_from_keys(&hash_keys); 2120 break; 2121 case 3: 2122 if (skb) 2123 mhash = fib_multipath_custom_hash_skb(net, skb); 2124 else 2125 mhash = fib_multipath_custom_hash_fl4(net, fl4); 2126 break; 2127 } 2128 2129 if (multipath_hash) 2130 mhash = jhash_2words(mhash, multipath_hash, 0); 2131 2132 return mhash >> 1; 2133} 2134#endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2135 2136static int ip_mkroute_input(struct sk_buff *skb, 2137 struct fib_result *res, 2138 struct in_device *in_dev, 2139 __be32 daddr, __be32 saddr, u32 tos, 2140 struct flow_keys *hkeys) 2141{ 2142#ifdef CONFIG_IP_ROUTE_MULTIPATH 2143 if (res->fi && fib_info_num_path(res->fi) > 1) { 2144 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2145 2146 fib_select_multipath(res, h); 2147 IPCB(skb)->flags |= IPSKB_MULTIPATH; 2148 } 2149#endif 2150 2151 /* create a routing cache entry */ 2152 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2153} 2154 2155/* Implements all the saddr-related checks as ip_route_input_slow(), 2156 * assuming daddr is valid and the destination is not a local broadcast one. 2157 * Uses the provided hint instead of performing a route lookup. 2158 */ 2159int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2160 u8 tos, struct net_device *dev, 2161 const struct sk_buff *hint) 2162{ 2163 struct in_device *in_dev = __in_dev_get_rcu(dev); 2164 struct rtable *rt = skb_rtable(hint); 2165 struct net *net = dev_net(dev); 2166 int err = -EINVAL; 2167 u32 tag = 0; 2168 2169 if (!in_dev) 2170 return -EINVAL; 2171 2172 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2173 goto martian_source; 2174 2175 if (ipv4_is_zeronet(saddr)) 2176 goto martian_source; 2177 2178 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2179 goto martian_source; 2180 2181 if (rt->rt_type != RTN_LOCAL) 2182 goto skip_validate_source; 2183 2184 tos &= IPTOS_RT_MASK; 2185 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag); 2186 if (err < 0) 2187 goto martian_source; 2188 2189skip_validate_source: 2190 skb_dst_copy(skb, hint); 2191 return 0; 2192 2193martian_source: 2194 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2195 return err; 2196} 2197 2198/* get device for dst_alloc with local routes */ 2199static struct net_device *ip_rt_get_dev(struct net *net, 2200 const struct fib_result *res) 2201{ 2202 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL; 2203 struct net_device *dev = NULL; 2204 2205 if (nhc) 2206 dev = l3mdev_master_dev_rcu(nhc->nhc_dev); 2207 2208 return dev ? : net->loopback_dev; 2209} 2210 2211/* 2212 * NOTE. We drop all the packets that has local source 2213 * addresses, because every properly looped back packet 2214 * must have correct destination already attached by output routine. 2215 * Changes in the enforced policies must be applied also to 2216 * ip_route_use_hint(). 2217 * 2218 * Such approach solves two big problems: 2219 * 1. Not simplex devices are handled properly. 2220 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2221 * called with rcu_read_lock() 2222 */ 2223 2224static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2225 u8 tos, struct net_device *dev, 2226 struct fib_result *res) 2227{ 2228 struct in_device *in_dev = __in_dev_get_rcu(dev); 2229 struct flow_keys *flkeys = NULL, _flkeys; 2230 struct net *net = dev_net(dev); 2231 struct ip_tunnel_info *tun_info; 2232 int err = -EINVAL; 2233 unsigned int flags = 0; 2234 u32 itag = 0; 2235 struct rtable *rth; 2236 struct flowi4 fl4; 2237 bool do_cache = true; 2238 2239 /* IP on this device is disabled. */ 2240 2241 if (!in_dev) 2242 goto out; 2243 2244 /* Check for the most weird martians, which can be not detected 2245 * by fib_lookup. 2246 */ 2247 2248 tun_info = skb_tunnel_info(skb); 2249 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2250 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2251 else 2252 fl4.flowi4_tun_key.tun_id = 0; 2253 skb_dst_drop(skb); 2254 2255 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2256 goto martian_source; 2257 2258 res->fi = NULL; 2259 res->table = NULL; 2260 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2261 goto brd_input; 2262 2263 /* Accept zero addresses only to limited broadcast; 2264 * I even do not know to fix it or not. Waiting for complains :-) 2265 */ 2266 if (ipv4_is_zeronet(saddr)) 2267 goto martian_source; 2268 2269 if (ipv4_is_zeronet(daddr)) 2270 goto martian_destination; 2271 2272 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2273 * and call it once if daddr or/and saddr are loopback addresses 2274 */ 2275 if (ipv4_is_loopback(daddr)) { 2276 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2277 goto martian_destination; 2278 } else if (ipv4_is_loopback(saddr)) { 2279 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2280 goto martian_source; 2281 } 2282 2283 /* 2284 * Now we are ready to route packet. 2285 */ 2286 fl4.flowi4_l3mdev = 0; 2287 fl4.flowi4_oif = 0; 2288 fl4.flowi4_iif = dev->ifindex; 2289 fl4.flowi4_mark = skb->mark; 2290 fl4.flowi4_tos = tos; 2291 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2292 fl4.flowi4_flags = 0; 2293 fl4.daddr = daddr; 2294 fl4.saddr = saddr; 2295 fl4.flowi4_uid = sock_net_uid(net, NULL); 2296 fl4.flowi4_multipath_hash = 0; 2297 2298 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2299 flkeys = &_flkeys; 2300 } else { 2301 fl4.flowi4_proto = 0; 2302 fl4.fl4_sport = 0; 2303 fl4.fl4_dport = 0; 2304 } 2305 2306 err = fib_lookup(net, &fl4, res, 0); 2307 if (err != 0) { 2308 if (!IN_DEV_FORWARD(in_dev)) 2309 err = -EHOSTUNREACH; 2310 goto no_route; 2311 } 2312 2313 if (res->type == RTN_BROADCAST) { 2314 if (IN_DEV_BFORWARD(in_dev)) 2315 goto make_route; 2316 /* not do cache if bc_forwarding is enabled */ 2317 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING)) 2318 do_cache = false; 2319 goto brd_input; 2320 } 2321 2322 if (res->type == RTN_LOCAL) { 2323 err = fib_validate_source(skb, saddr, daddr, tos, 2324 0, dev, in_dev, &itag); 2325 if (err < 0) 2326 goto martian_source; 2327 goto local_input; 2328 } 2329 2330 if (!IN_DEV_FORWARD(in_dev)) { 2331 err = -EHOSTUNREACH; 2332 goto no_route; 2333 } 2334 if (res->type != RTN_UNICAST) 2335 goto martian_destination; 2336 2337make_route: 2338 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2339out: return err; 2340 2341brd_input: 2342 if (skb->protocol != htons(ETH_P_IP)) 2343 goto e_inval; 2344 2345 if (!ipv4_is_zeronet(saddr)) { 2346 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2347 in_dev, &itag); 2348 if (err < 0) 2349 goto martian_source; 2350 } 2351 flags |= RTCF_BROADCAST; 2352 res->type = RTN_BROADCAST; 2353 RT_CACHE_STAT_INC(in_brd); 2354 2355local_input: 2356 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 2357 IPCB(skb)->flags |= IPSKB_NOPOLICY; 2358 2359 do_cache &= res->fi && !itag; 2360 if (do_cache) { 2361 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2362 2363 rth = rcu_dereference(nhc->nhc_rth_input); 2364 if (rt_cache_valid(rth)) { 2365 skb_dst_set_noref(skb, &rth->dst); 2366 err = 0; 2367 goto out; 2368 } 2369 } 2370 2371 rth = rt_dst_alloc(ip_rt_get_dev(net, res), 2372 flags | RTCF_LOCAL, res->type, false); 2373 if (!rth) 2374 goto e_nobufs; 2375 2376 rth->dst.output= ip_rt_bug; 2377#ifdef CONFIG_IP_ROUTE_CLASSID 2378 rth->dst.tclassid = itag; 2379#endif 2380 rth->rt_is_input = 1; 2381 2382 RT_CACHE_STAT_INC(in_slow_tot); 2383 if (res->type == RTN_UNREACHABLE) { 2384 rth->dst.input= ip_error; 2385 rth->dst.error= -err; 2386 rth->rt_flags &= ~RTCF_LOCAL; 2387 } 2388 2389 if (do_cache) { 2390 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2391 2392 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2393 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2394 WARN_ON(rth->dst.input == lwtunnel_input); 2395 rth->dst.lwtstate->orig_input = rth->dst.input; 2396 rth->dst.input = lwtunnel_input; 2397 } 2398 2399 if (unlikely(!rt_cache_route(nhc, rth))) 2400 rt_add_uncached_list(rth); 2401 } 2402 skb_dst_set(skb, &rth->dst); 2403 err = 0; 2404 goto out; 2405 2406no_route: 2407 RT_CACHE_STAT_INC(in_no_route); 2408 res->type = RTN_UNREACHABLE; 2409 res->fi = NULL; 2410 res->table = NULL; 2411 goto local_input; 2412 2413 /* 2414 * Do not cache martian addresses: they should be logged (RFC1812) 2415 */ 2416martian_destination: 2417 RT_CACHE_STAT_INC(in_martian_dst); 2418#ifdef CONFIG_IP_ROUTE_VERBOSE 2419 if (IN_DEV_LOG_MARTIANS(in_dev)) 2420 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2421 &daddr, &saddr, dev->name); 2422#endif 2423 2424e_inval: 2425 err = -EINVAL; 2426 goto out; 2427 2428e_nobufs: 2429 err = -ENOBUFS; 2430 goto out; 2431 2432martian_source: 2433 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2434 goto out; 2435} 2436 2437/* called with rcu_read_lock held */ 2438static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2439 u8 tos, struct net_device *dev, struct fib_result *res) 2440{ 2441 /* Multicast recognition logic is moved from route cache to here. 2442 * The problem was that too many Ethernet cards have broken/missing 2443 * hardware multicast filters :-( As result the host on multicasting 2444 * network acquires a lot of useless route cache entries, sort of 2445 * SDR messages from all the world. Now we try to get rid of them. 2446 * Really, provided software IP multicast filter is organized 2447 * reasonably (at least, hashed), it does not result in a slowdown 2448 * comparing with route cache reject entries. 2449 * Note, that multicast routers are not affected, because 2450 * route cache entry is created eventually. 2451 */ 2452 if (ipv4_is_multicast(daddr)) { 2453 struct in_device *in_dev = __in_dev_get_rcu(dev); 2454 int our = 0; 2455 int err = -EINVAL; 2456 2457 if (!in_dev) 2458 return err; 2459 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2460 ip_hdr(skb)->protocol); 2461 2462 /* check l3 master if no match yet */ 2463 if (!our && netif_is_l3_slave(dev)) { 2464 struct in_device *l3_in_dev; 2465 2466 l3_in_dev = __in_dev_get_rcu(skb->dev); 2467 if (l3_in_dev) 2468 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2469 ip_hdr(skb)->protocol); 2470 } 2471 2472 if (our 2473#ifdef CONFIG_IP_MROUTE 2474 || 2475 (!ipv4_is_local_multicast(daddr) && 2476 IN_DEV_MFORWARD(in_dev)) 2477#endif 2478 ) { 2479 err = ip_route_input_mc(skb, daddr, saddr, 2480 tos, dev, our); 2481 } 2482 return err; 2483 } 2484 2485 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2486} 2487 2488int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2489 u8 tos, struct net_device *dev) 2490{ 2491 struct fib_result res; 2492 int err; 2493 2494 tos &= IPTOS_RT_MASK; 2495 rcu_read_lock(); 2496 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2497 rcu_read_unlock(); 2498 2499 return err; 2500} 2501EXPORT_SYMBOL(ip_route_input_noref); 2502 2503/* called with rcu_read_lock() */ 2504static struct rtable *__mkroute_output(const struct fib_result *res, 2505 const struct flowi4 *fl4, int orig_oif, 2506 struct net_device *dev_out, 2507 unsigned int flags) 2508{ 2509 struct fib_info *fi = res->fi; 2510 struct fib_nh_exception *fnhe; 2511 struct in_device *in_dev; 2512 u16 type = res->type; 2513 struct rtable *rth; 2514 bool do_cache; 2515 2516 in_dev = __in_dev_get_rcu(dev_out); 2517 if (!in_dev) 2518 return ERR_PTR(-EINVAL); 2519 2520 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2521 if (ipv4_is_loopback(fl4->saddr) && 2522 !(dev_out->flags & IFF_LOOPBACK) && 2523 !netif_is_l3_master(dev_out)) 2524 return ERR_PTR(-EINVAL); 2525 2526 if (ipv4_is_lbcast(fl4->daddr)) 2527 type = RTN_BROADCAST; 2528 else if (ipv4_is_multicast(fl4->daddr)) 2529 type = RTN_MULTICAST; 2530 else if (ipv4_is_zeronet(fl4->daddr)) 2531 return ERR_PTR(-EINVAL); 2532 2533 if (dev_out->flags & IFF_LOOPBACK) 2534 flags |= RTCF_LOCAL; 2535 2536 do_cache = true; 2537 if (type == RTN_BROADCAST) { 2538 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2539 fi = NULL; 2540 } else if (type == RTN_MULTICAST) { 2541 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2542 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2543 fl4->flowi4_proto)) 2544 flags &= ~RTCF_LOCAL; 2545 else 2546 do_cache = false; 2547 /* If multicast route do not exist use 2548 * default one, but do not gateway in this case. 2549 * Yes, it is hack. 2550 */ 2551 if (fi && res->prefixlen < 4) 2552 fi = NULL; 2553 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2554 (orig_oif != dev_out->ifindex)) { 2555 /* For local routes that require a particular output interface 2556 * we do not want to cache the result. Caching the result 2557 * causes incorrect behaviour when there are multiple source 2558 * addresses on the interface, the end result being that if the 2559 * intended recipient is waiting on that interface for the 2560 * packet he won't receive it because it will be delivered on 2561 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2562 * be set to the loopback interface as well. 2563 */ 2564 do_cache = false; 2565 } 2566 2567 fnhe = NULL; 2568 do_cache &= fi != NULL; 2569 if (fi) { 2570 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2571 struct rtable __rcu **prth; 2572 2573 fnhe = find_exception(nhc, fl4->daddr); 2574 if (!do_cache) 2575 goto add; 2576 if (fnhe) { 2577 prth = &fnhe->fnhe_rth_output; 2578 } else { 2579 if (unlikely(fl4->flowi4_flags & 2580 FLOWI_FLAG_KNOWN_NH && 2581 !(nhc->nhc_gw_family && 2582 nhc->nhc_scope == RT_SCOPE_LINK))) { 2583 do_cache = false; 2584 goto add; 2585 } 2586 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2587 } 2588 rth = rcu_dereference(*prth); 2589 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2590 return rth; 2591 } 2592 2593add: 2594 rth = rt_dst_alloc(dev_out, flags, type, 2595 IN_DEV_ORCONF(in_dev, NOXFRM)); 2596 if (!rth) 2597 return ERR_PTR(-ENOBUFS); 2598 2599 rth->rt_iif = orig_oif; 2600 2601 RT_CACHE_STAT_INC(out_slow_tot); 2602 2603 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2604 if (flags & RTCF_LOCAL && 2605 !(dev_out->flags & IFF_LOOPBACK)) { 2606 rth->dst.output = ip_mc_output; 2607 RT_CACHE_STAT_INC(out_slow_mc); 2608 } 2609#ifdef CONFIG_IP_MROUTE 2610 if (type == RTN_MULTICAST) { 2611 if (IN_DEV_MFORWARD(in_dev) && 2612 !ipv4_is_local_multicast(fl4->daddr)) { 2613 rth->dst.input = ip_mr_input; 2614 rth->dst.output = ip_mc_output; 2615 } 2616 } 2617#endif 2618 } 2619 2620 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2621 lwtunnel_set_redirect(&rth->dst); 2622 2623 return rth; 2624} 2625 2626/* 2627 * Major route resolver routine. 2628 */ 2629 2630struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2631 const struct sk_buff *skb) 2632{ 2633 struct fib_result res = { 2634 .type = RTN_UNSPEC, 2635 .fi = NULL, 2636 .table = NULL, 2637 .tclassid = 0, 2638 }; 2639 struct rtable *rth; 2640 2641 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2642 ip_rt_fix_tos(fl4); 2643 2644 rcu_read_lock(); 2645 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2646 rcu_read_unlock(); 2647 2648 return rth; 2649} 2650EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2651 2652struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2653 struct fib_result *res, 2654 const struct sk_buff *skb) 2655{ 2656 struct net_device *dev_out = NULL; 2657 int orig_oif = fl4->flowi4_oif; 2658 unsigned int flags = 0; 2659 struct rtable *rth; 2660 int err; 2661 2662 if (fl4->saddr) { 2663 if (ipv4_is_multicast(fl4->saddr) || 2664 ipv4_is_lbcast(fl4->saddr) || 2665 ipv4_is_zeronet(fl4->saddr)) { 2666 rth = ERR_PTR(-EINVAL); 2667 goto out; 2668 } 2669 2670 rth = ERR_PTR(-ENETUNREACH); 2671 2672 /* I removed check for oif == dev_out->oif here. 2673 * It was wrong for two reasons: 2674 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2675 * is assigned to multiple interfaces. 2676 * 2. Moreover, we are allowed to send packets with saddr 2677 * of another iface. --ANK 2678 */ 2679 2680 if (fl4->flowi4_oif == 0 && 2681 (ipv4_is_multicast(fl4->daddr) || 2682 ipv4_is_lbcast(fl4->daddr))) { 2683 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2684 dev_out = __ip_dev_find(net, fl4->saddr, false); 2685 if (!dev_out) 2686 goto out; 2687 2688 /* Special hack: user can direct multicasts 2689 * and limited broadcast via necessary interface 2690 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2691 * This hack is not just for fun, it allows 2692 * vic,vat and friends to work. 2693 * They bind socket to loopback, set ttl to zero 2694 * and expect that it will work. 2695 * From the viewpoint of routing cache they are broken, 2696 * because we are not allowed to build multicast path 2697 * with loopback source addr (look, routing cache 2698 * cannot know, that ttl is zero, so that packet 2699 * will not leave this host and route is valid). 2700 * Luckily, this hack is good workaround. 2701 */ 2702 2703 fl4->flowi4_oif = dev_out->ifindex; 2704 goto make_route; 2705 } 2706 2707 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2708 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2709 if (!__ip_dev_find(net, fl4->saddr, false)) 2710 goto out; 2711 } 2712 } 2713 2714 2715 if (fl4->flowi4_oif) { 2716 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2717 rth = ERR_PTR(-ENODEV); 2718 if (!dev_out) 2719 goto out; 2720 2721 /* RACE: Check return value of inet_select_addr instead. */ 2722 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2723 rth = ERR_PTR(-ENETUNREACH); 2724 goto out; 2725 } 2726 if (ipv4_is_local_multicast(fl4->daddr) || 2727 ipv4_is_lbcast(fl4->daddr) || 2728 fl4->flowi4_proto == IPPROTO_IGMP) { 2729 if (!fl4->saddr) 2730 fl4->saddr = inet_select_addr(dev_out, 0, 2731 RT_SCOPE_LINK); 2732 goto make_route; 2733 } 2734 if (!fl4->saddr) { 2735 if (ipv4_is_multicast(fl4->daddr)) 2736 fl4->saddr = inet_select_addr(dev_out, 0, 2737 fl4->flowi4_scope); 2738 else if (!fl4->daddr) 2739 fl4->saddr = inet_select_addr(dev_out, 0, 2740 RT_SCOPE_HOST); 2741 } 2742 } 2743 2744 if (!fl4->daddr) { 2745 fl4->daddr = fl4->saddr; 2746 if (!fl4->daddr) 2747 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2748 dev_out = net->loopback_dev; 2749 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2750 res->type = RTN_LOCAL; 2751 flags |= RTCF_LOCAL; 2752 goto make_route; 2753 } 2754 2755 err = fib_lookup(net, fl4, res, 0); 2756 if (err) { 2757 res->fi = NULL; 2758 res->table = NULL; 2759 if (fl4->flowi4_oif && 2760 (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) { 2761 /* Apparently, routing tables are wrong. Assume, 2762 * that the destination is on link. 2763 * 2764 * WHY? DW. 2765 * Because we are allowed to send to iface 2766 * even if it has NO routes and NO assigned 2767 * addresses. When oif is specified, routing 2768 * tables are looked up with only one purpose: 2769 * to catch if destination is gatewayed, rather than 2770 * direct. Moreover, if MSG_DONTROUTE is set, 2771 * we send packet, ignoring both routing tables 2772 * and ifaddr state. --ANK 2773 * 2774 * 2775 * We could make it even if oif is unknown, 2776 * likely IPv6, but we do not. 2777 */ 2778 2779 if (fl4->saddr == 0) 2780 fl4->saddr = inet_select_addr(dev_out, 0, 2781 RT_SCOPE_LINK); 2782 res->type = RTN_UNICAST; 2783 goto make_route; 2784 } 2785 rth = ERR_PTR(err); 2786 goto out; 2787 } 2788 2789 if (res->type == RTN_LOCAL) { 2790 if (!fl4->saddr) { 2791 if (res->fi->fib_prefsrc) 2792 fl4->saddr = res->fi->fib_prefsrc; 2793 else 2794 fl4->saddr = fl4->daddr; 2795 } 2796 2797 /* L3 master device is the loopback for that domain */ 2798 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2799 net->loopback_dev; 2800 2801 /* make sure orig_oif points to fib result device even 2802 * though packet rx/tx happens over loopback or l3mdev 2803 */ 2804 orig_oif = FIB_RES_OIF(*res); 2805 2806 fl4->flowi4_oif = dev_out->ifindex; 2807 flags |= RTCF_LOCAL; 2808 goto make_route; 2809 } 2810 2811 fib_select_path(net, res, fl4, skb); 2812 2813 dev_out = FIB_RES_DEV(*res); 2814 2815make_route: 2816 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2817 2818out: 2819 return rth; 2820} 2821 2822static struct dst_ops ipv4_dst_blackhole_ops = { 2823 .family = AF_INET, 2824 .default_advmss = ipv4_default_advmss, 2825 .neigh_lookup = ipv4_neigh_lookup, 2826 .check = dst_blackhole_check, 2827 .cow_metrics = dst_blackhole_cow_metrics, 2828 .update_pmtu = dst_blackhole_update_pmtu, 2829 .redirect = dst_blackhole_redirect, 2830 .mtu = dst_blackhole_mtu, 2831}; 2832 2833struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2834{ 2835 struct rtable *ort = (struct rtable *) dst_orig; 2836 struct rtable *rt; 2837 2838 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0); 2839 if (rt) { 2840 struct dst_entry *new = &rt->dst; 2841 2842 new->__use = 1; 2843 new->input = dst_discard; 2844 new->output = dst_discard_out; 2845 2846 new->dev = net->loopback_dev; 2847 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC); 2848 2849 rt->rt_is_input = ort->rt_is_input; 2850 rt->rt_iif = ort->rt_iif; 2851 rt->rt_pmtu = ort->rt_pmtu; 2852 rt->rt_mtu_locked = ort->rt_mtu_locked; 2853 2854 rt->rt_genid = rt_genid_ipv4(net); 2855 rt->rt_flags = ort->rt_flags; 2856 rt->rt_type = ort->rt_type; 2857 rt->rt_uses_gateway = ort->rt_uses_gateway; 2858 rt->rt_gw_family = ort->rt_gw_family; 2859 if (rt->rt_gw_family == AF_INET) 2860 rt->rt_gw4 = ort->rt_gw4; 2861 else if (rt->rt_gw_family == AF_INET6) 2862 rt->rt_gw6 = ort->rt_gw6; 2863 } 2864 2865 dst_release(dst_orig); 2866 2867 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2868} 2869 2870struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2871 const struct sock *sk) 2872{ 2873 struct rtable *rt = __ip_route_output_key(net, flp4); 2874 2875 if (IS_ERR(rt)) 2876 return rt; 2877 2878 if (flp4->flowi4_proto) { 2879 flp4->flowi4_oif = rt->dst.dev->ifindex; 2880 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2881 flowi4_to_flowi(flp4), 2882 sk, 0); 2883 } 2884 2885 return rt; 2886} 2887EXPORT_SYMBOL_GPL(ip_route_output_flow); 2888 2889/* called with rcu_read_lock held */ 2890static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2891 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2892 struct sk_buff *skb, u32 portid, u32 seq, 2893 unsigned int flags) 2894{ 2895 struct rtmsg *r; 2896 struct nlmsghdr *nlh; 2897 unsigned long expires = 0; 2898 u32 error; 2899 u32 metrics[RTAX_MAX]; 2900 2901 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2902 if (!nlh) 2903 return -EMSGSIZE; 2904 2905 r = nlmsg_data(nlh); 2906 r->rtm_family = AF_INET; 2907 r->rtm_dst_len = 32; 2908 r->rtm_src_len = 0; 2909 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2910 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2911 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2912 goto nla_put_failure; 2913 r->rtm_type = rt->rt_type; 2914 r->rtm_scope = RT_SCOPE_UNIVERSE; 2915 r->rtm_protocol = RTPROT_UNSPEC; 2916 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2917 if (rt->rt_flags & RTCF_NOTIFY) 2918 r->rtm_flags |= RTM_F_NOTIFY; 2919 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2920 r->rtm_flags |= RTCF_DOREDIRECT; 2921 2922 if (nla_put_in_addr(skb, RTA_DST, dst)) 2923 goto nla_put_failure; 2924 if (src) { 2925 r->rtm_src_len = 32; 2926 if (nla_put_in_addr(skb, RTA_SRC, src)) 2927 goto nla_put_failure; 2928 } 2929 if (rt->dst.dev && 2930 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2931 goto nla_put_failure; 2932 if (rt->dst.lwtstate && 2933 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 2934 goto nla_put_failure; 2935#ifdef CONFIG_IP_ROUTE_CLASSID 2936 if (rt->dst.tclassid && 2937 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2938 goto nla_put_failure; 2939#endif 2940 if (fl4 && !rt_is_input_route(rt) && 2941 fl4->saddr != src) { 2942 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2943 goto nla_put_failure; 2944 } 2945 if (rt->rt_uses_gateway) { 2946 if (rt->rt_gw_family == AF_INET && 2947 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2948 goto nla_put_failure; 2949 } else if (rt->rt_gw_family == AF_INET6) { 2950 int alen = sizeof(struct in6_addr); 2951 struct nlattr *nla; 2952 struct rtvia *via; 2953 2954 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2955 if (!nla) 2956 goto nla_put_failure; 2957 2958 via = nla_data(nla); 2959 via->rtvia_family = AF_INET6; 2960 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2961 } 2962 } 2963 2964 expires = rt->dst.expires; 2965 if (expires) { 2966 unsigned long now = jiffies; 2967 2968 if (time_before(now, expires)) 2969 expires -= now; 2970 else 2971 expires = 0; 2972 } 2973 2974 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2975 if (rt->rt_pmtu && expires) 2976 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2977 if (rt->rt_mtu_locked && expires) 2978 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2979 if (rtnetlink_put_metrics(skb, metrics) < 0) 2980 goto nla_put_failure; 2981 2982 if (fl4) { 2983 if (fl4->flowi4_mark && 2984 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2985 goto nla_put_failure; 2986 2987 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2988 nla_put_u32(skb, RTA_UID, 2989 from_kuid_munged(current_user_ns(), 2990 fl4->flowi4_uid))) 2991 goto nla_put_failure; 2992 2993 if (rt_is_input_route(rt)) { 2994#ifdef CONFIG_IP_MROUTE 2995 if (ipv4_is_multicast(dst) && 2996 !ipv4_is_local_multicast(dst) && 2997 IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) { 2998 int err = ipmr_get_route(net, skb, 2999 fl4->saddr, fl4->daddr, 3000 r, portid); 3001 3002 if (err <= 0) { 3003 if (err == 0) 3004 return 0; 3005 goto nla_put_failure; 3006 } 3007 } else 3008#endif 3009 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 3010 goto nla_put_failure; 3011 } 3012 } 3013 3014 error = rt->dst.error; 3015 3016 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 3017 goto nla_put_failure; 3018 3019 nlmsg_end(skb, nlh); 3020 return 0; 3021 3022nla_put_failure: 3023 nlmsg_cancel(skb, nlh); 3024 return -EMSGSIZE; 3025} 3026 3027static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 3028 struct netlink_callback *cb, u32 table_id, 3029 struct fnhe_hash_bucket *bucket, int genid, 3030 int *fa_index, int fa_start, unsigned int flags) 3031{ 3032 int i; 3033 3034 for (i = 0; i < FNHE_HASH_SIZE; i++) { 3035 struct fib_nh_exception *fnhe; 3036 3037 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 3038 fnhe = rcu_dereference(fnhe->fnhe_next)) { 3039 struct rtable *rt; 3040 int err; 3041 3042 if (*fa_index < fa_start) 3043 goto next; 3044 3045 if (fnhe->fnhe_genid != genid) 3046 goto next; 3047 3048 if (fnhe->fnhe_expires && 3049 time_after(jiffies, fnhe->fnhe_expires)) 3050 goto next; 3051 3052 rt = rcu_dereference(fnhe->fnhe_rth_input); 3053 if (!rt) 3054 rt = rcu_dereference(fnhe->fnhe_rth_output); 3055 if (!rt) 3056 goto next; 3057 3058 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 3059 table_id, NULL, skb, 3060 NETLINK_CB(cb->skb).portid, 3061 cb->nlh->nlmsg_seq, flags); 3062 if (err) 3063 return err; 3064next: 3065 (*fa_index)++; 3066 } 3067 } 3068 3069 return 0; 3070} 3071 3072int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 3073 u32 table_id, struct fib_info *fi, 3074 int *fa_index, int fa_start, unsigned int flags) 3075{ 3076 struct net *net = sock_net(cb->skb->sk); 3077 int nhsel, genid = fnhe_genid(net); 3078 3079 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 3080 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 3081 struct fnhe_hash_bucket *bucket; 3082 int err; 3083 3084 if (nhc->nhc_flags & RTNH_F_DEAD) 3085 continue; 3086 3087 rcu_read_lock(); 3088 bucket = rcu_dereference(nhc->nhc_exceptions); 3089 err = 0; 3090 if (bucket) 3091 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 3092 genid, fa_index, fa_start, 3093 flags); 3094 rcu_read_unlock(); 3095 if (err) 3096 return err; 3097 } 3098 3099 return 0; 3100} 3101 3102static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3103 u8 ip_proto, __be16 sport, 3104 __be16 dport) 3105{ 3106 struct sk_buff *skb; 3107 struct iphdr *iph; 3108 3109 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3110 if (!skb) 3111 return NULL; 3112 3113 /* Reserve room for dummy headers, this skb can pass 3114 * through good chunk of routing engine. 3115 */ 3116 skb_reset_mac_header(skb); 3117 skb_reset_network_header(skb); 3118 skb->protocol = htons(ETH_P_IP); 3119 iph = skb_put(skb, sizeof(struct iphdr)); 3120 iph->protocol = ip_proto; 3121 iph->saddr = src; 3122 iph->daddr = dst; 3123 iph->version = 0x4; 3124 iph->frag_off = 0; 3125 iph->ihl = 0x5; 3126 skb_set_transport_header(skb, skb->len); 3127 3128 switch (iph->protocol) { 3129 case IPPROTO_UDP: { 3130 struct udphdr *udph; 3131 3132 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3133 udph->source = sport; 3134 udph->dest = dport; 3135 udph->len = htons(sizeof(struct udphdr)); 3136 udph->check = 0; 3137 break; 3138 } 3139 case IPPROTO_TCP: { 3140 struct tcphdr *tcph; 3141 3142 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3143 tcph->source = sport; 3144 tcph->dest = dport; 3145 tcph->doff = sizeof(struct tcphdr) / 4; 3146 tcph->rst = 1; 3147 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3148 src, dst, 0); 3149 break; 3150 } 3151 case IPPROTO_ICMP: { 3152 struct icmphdr *icmph; 3153 3154 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3155 icmph->type = ICMP_ECHO; 3156 icmph->code = 0; 3157 } 3158 } 3159 3160 return skb; 3161} 3162 3163static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3164 const struct nlmsghdr *nlh, 3165 struct nlattr **tb, 3166 struct netlink_ext_ack *extack) 3167{ 3168 struct rtmsg *rtm; 3169 int i, err; 3170 3171 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3172 NL_SET_ERR_MSG(extack, 3173 "ipv4: Invalid header for route get request"); 3174 return -EINVAL; 3175 } 3176 3177 if (!netlink_strict_get_check(skb)) 3178 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3179 rtm_ipv4_policy, extack); 3180 3181 rtm = nlmsg_data(nlh); 3182 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3183 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3184 rtm->rtm_table || rtm->rtm_protocol || 3185 rtm->rtm_scope || rtm->rtm_type) { 3186 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3187 return -EINVAL; 3188 } 3189 3190 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3191 RTM_F_LOOKUP_TABLE | 3192 RTM_F_FIB_MATCH)) { 3193 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3194 return -EINVAL; 3195 } 3196 3197 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3198 rtm_ipv4_policy, extack); 3199 if (err) 3200 return err; 3201 3202 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3203 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3204 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3205 return -EINVAL; 3206 } 3207 3208 for (i = 0; i <= RTA_MAX; i++) { 3209 if (!tb[i]) 3210 continue; 3211 3212 switch (i) { 3213 case RTA_IIF: 3214 case RTA_OIF: 3215 case RTA_SRC: 3216 case RTA_DST: 3217 case RTA_IP_PROTO: 3218 case RTA_SPORT: 3219 case RTA_DPORT: 3220 case RTA_MARK: 3221 case RTA_UID: 3222 break; 3223 default: 3224 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3225 return -EINVAL; 3226 } 3227 } 3228 3229 return 0; 3230} 3231 3232static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3233 struct netlink_ext_ack *extack) 3234{ 3235 struct net *net = sock_net(in_skb->sk); 3236 struct nlattr *tb[RTA_MAX+1]; 3237 u32 table_id = RT_TABLE_MAIN; 3238 __be16 sport = 0, dport = 0; 3239 struct fib_result res = {}; 3240 u8 ip_proto = IPPROTO_UDP; 3241 struct rtable *rt = NULL; 3242 struct sk_buff *skb; 3243 struct rtmsg *rtm; 3244 struct flowi4 fl4 = {}; 3245 __be32 dst = 0; 3246 __be32 src = 0; 3247 kuid_t uid; 3248 u32 iif; 3249 int err; 3250 int mark; 3251 3252 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3253 if (err < 0) 3254 return err; 3255 3256 rtm = nlmsg_data(nlh); 3257 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3258 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3259 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3260 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3261 if (tb[RTA_UID]) 3262 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3263 else 3264 uid = (iif ? INVALID_UID : current_uid()); 3265 3266 if (tb[RTA_IP_PROTO]) { 3267 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3268 &ip_proto, AF_INET, extack); 3269 if (err) 3270 return err; 3271 } 3272 3273 if (tb[RTA_SPORT]) 3274 sport = nla_get_be16(tb[RTA_SPORT]); 3275 3276 if (tb[RTA_DPORT]) 3277 dport = nla_get_be16(tb[RTA_DPORT]); 3278 3279 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3280 if (!skb) 3281 return -ENOBUFS; 3282 3283 fl4.daddr = dst; 3284 fl4.saddr = src; 3285 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK; 3286 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3287 fl4.flowi4_mark = mark; 3288 fl4.flowi4_uid = uid; 3289 if (sport) 3290 fl4.fl4_sport = sport; 3291 if (dport) 3292 fl4.fl4_dport = dport; 3293 fl4.flowi4_proto = ip_proto; 3294 3295 rcu_read_lock(); 3296 3297 if (iif) { 3298 struct net_device *dev; 3299 3300 dev = dev_get_by_index_rcu(net, iif); 3301 if (!dev) { 3302 err = -ENODEV; 3303 goto errout_rcu; 3304 } 3305 3306 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3307 skb->dev = dev; 3308 skb->mark = mark; 3309 err = ip_route_input_rcu(skb, dst, src, 3310 rtm->rtm_tos & IPTOS_RT_MASK, dev, 3311 &res); 3312 3313 rt = skb_rtable(skb); 3314 if (err == 0 && rt->dst.error) 3315 err = -rt->dst.error; 3316 } else { 3317 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3318 skb->dev = net->loopback_dev; 3319 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3320 err = 0; 3321 if (IS_ERR(rt)) 3322 err = PTR_ERR(rt); 3323 else 3324 skb_dst_set(skb, &rt->dst); 3325 } 3326 3327 if (err) 3328 goto errout_rcu; 3329 3330 if (rtm->rtm_flags & RTM_F_NOTIFY) 3331 rt->rt_flags |= RTCF_NOTIFY; 3332 3333 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3334 table_id = res.table ? res.table->tb_id : 0; 3335 3336 /* reset skb for netlink reply msg */ 3337 skb_trim(skb, 0); 3338 skb_reset_network_header(skb); 3339 skb_reset_transport_header(skb); 3340 skb_reset_mac_header(skb); 3341 3342 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3343 struct fib_rt_info fri; 3344 3345 if (!res.fi) { 3346 err = fib_props[res.type].error; 3347 if (!err) 3348 err = -EHOSTUNREACH; 3349 goto errout_rcu; 3350 } 3351 fri.fi = res.fi; 3352 fri.tb_id = table_id; 3353 fri.dst = res.prefix; 3354 fri.dst_len = res.prefixlen; 3355 fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos); 3356 fri.type = rt->rt_type; 3357 fri.offload = 0; 3358 fri.trap = 0; 3359 fri.offload_failed = 0; 3360 if (res.fa_head) { 3361 struct fib_alias *fa; 3362 3363 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3364 u8 slen = 32 - fri.dst_len; 3365 3366 if (fa->fa_slen == slen && 3367 fa->tb_id == fri.tb_id && 3368 fa->fa_dscp == fri.dscp && 3369 fa->fa_info == res.fi && 3370 fa->fa_type == fri.type) { 3371 fri.offload = READ_ONCE(fa->offload); 3372 fri.trap = READ_ONCE(fa->trap); 3373 fri.offload_failed = 3374 READ_ONCE(fa->offload_failed); 3375 break; 3376 } 3377 } 3378 } 3379 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3380 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3381 } else { 3382 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3383 NETLINK_CB(in_skb).portid, 3384 nlh->nlmsg_seq, 0); 3385 } 3386 if (err < 0) 3387 goto errout_rcu; 3388 3389 rcu_read_unlock(); 3390 3391 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3392 3393errout_free: 3394 return err; 3395errout_rcu: 3396 rcu_read_unlock(); 3397 kfree_skb(skb); 3398 goto errout_free; 3399} 3400 3401void ip_rt_multicast_event(struct in_device *in_dev) 3402{ 3403 rt_cache_flush(dev_net(in_dev->dev)); 3404} 3405 3406#ifdef CONFIG_SYSCTL 3407static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3408static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3409static int ip_rt_gc_elasticity __read_mostly = 8; 3410static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3411 3412static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3413 void *buffer, size_t *lenp, loff_t *ppos) 3414{ 3415 struct net *net = (struct net *)__ctl->extra1; 3416 3417 if (write) { 3418 rt_cache_flush(net); 3419 fnhe_genid_bump(net); 3420 return 0; 3421 } 3422 3423 return -EINVAL; 3424} 3425 3426static struct ctl_table ipv4_route_table[] = { 3427 { 3428 .procname = "gc_thresh", 3429 .data = &ipv4_dst_ops.gc_thresh, 3430 .maxlen = sizeof(int), 3431 .mode = 0644, 3432 .proc_handler = proc_dointvec, 3433 }, 3434 { 3435 .procname = "max_size", 3436 .data = &ip_rt_max_size, 3437 .maxlen = sizeof(int), 3438 .mode = 0644, 3439 .proc_handler = proc_dointvec, 3440 }, 3441 { 3442 /* Deprecated. Use gc_min_interval_ms */ 3443 3444 .procname = "gc_min_interval", 3445 .data = &ip_rt_gc_min_interval, 3446 .maxlen = sizeof(int), 3447 .mode = 0644, 3448 .proc_handler = proc_dointvec_jiffies, 3449 }, 3450 { 3451 .procname = "gc_min_interval_ms", 3452 .data = &ip_rt_gc_min_interval, 3453 .maxlen = sizeof(int), 3454 .mode = 0644, 3455 .proc_handler = proc_dointvec_ms_jiffies, 3456 }, 3457 { 3458 .procname = "gc_timeout", 3459 .data = &ip_rt_gc_timeout, 3460 .maxlen = sizeof(int), 3461 .mode = 0644, 3462 .proc_handler = proc_dointvec_jiffies, 3463 }, 3464 { 3465 .procname = "gc_interval", 3466 .data = &ip_rt_gc_interval, 3467 .maxlen = sizeof(int), 3468 .mode = 0644, 3469 .proc_handler = proc_dointvec_jiffies, 3470 }, 3471 { 3472 .procname = "redirect_load", 3473 .data = &ip_rt_redirect_load, 3474 .maxlen = sizeof(int), 3475 .mode = 0644, 3476 .proc_handler = proc_dointvec, 3477 }, 3478 { 3479 .procname = "redirect_number", 3480 .data = &ip_rt_redirect_number, 3481 .maxlen = sizeof(int), 3482 .mode = 0644, 3483 .proc_handler = proc_dointvec, 3484 }, 3485 { 3486 .procname = "redirect_silence", 3487 .data = &ip_rt_redirect_silence, 3488 .maxlen = sizeof(int), 3489 .mode = 0644, 3490 .proc_handler = proc_dointvec, 3491 }, 3492 { 3493 .procname = "error_cost", 3494 .data = &ip_rt_error_cost, 3495 .maxlen = sizeof(int), 3496 .mode = 0644, 3497 .proc_handler = proc_dointvec, 3498 }, 3499 { 3500 .procname = "error_burst", 3501 .data = &ip_rt_error_burst, 3502 .maxlen = sizeof(int), 3503 .mode = 0644, 3504 .proc_handler = proc_dointvec, 3505 }, 3506 { 3507 .procname = "gc_elasticity", 3508 .data = &ip_rt_gc_elasticity, 3509 .maxlen = sizeof(int), 3510 .mode = 0644, 3511 .proc_handler = proc_dointvec, 3512 }, 3513 { } 3514}; 3515 3516static const char ipv4_route_flush_procname[] = "flush"; 3517 3518static struct ctl_table ipv4_route_netns_table[] = { 3519 { 3520 .procname = ipv4_route_flush_procname, 3521 .maxlen = sizeof(int), 3522 .mode = 0200, 3523 .proc_handler = ipv4_sysctl_rtcache_flush, 3524 }, 3525 { 3526 .procname = "min_pmtu", 3527 .data = &init_net.ipv4.ip_rt_min_pmtu, 3528 .maxlen = sizeof(int), 3529 .mode = 0644, 3530 .proc_handler = proc_dointvec_minmax, 3531 .extra1 = &ip_min_valid_pmtu, 3532 }, 3533 { 3534 .procname = "mtu_expires", 3535 .data = &init_net.ipv4.ip_rt_mtu_expires, 3536 .maxlen = sizeof(int), 3537 .mode = 0644, 3538 .proc_handler = proc_dointvec_jiffies, 3539 }, 3540 { 3541 .procname = "min_adv_mss", 3542 .data = &init_net.ipv4.ip_rt_min_advmss, 3543 .maxlen = sizeof(int), 3544 .mode = 0644, 3545 .proc_handler = proc_dointvec, 3546 }, 3547 { }, 3548}; 3549 3550static __net_init int sysctl_route_net_init(struct net *net) 3551{ 3552 struct ctl_table *tbl; 3553 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table); 3554 3555 tbl = ipv4_route_netns_table; 3556 if (!net_eq(net, &init_net)) { 3557 int i; 3558 3559 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL); 3560 if (!tbl) 3561 goto err_dup; 3562 3563 /* Don't export non-whitelisted sysctls to unprivileged users */ 3564 if (net->user_ns != &init_user_ns) { 3565 if (tbl[0].procname != ipv4_route_flush_procname) { 3566 tbl[0].procname = NULL; 3567 table_size = 0; 3568 } 3569 } 3570 3571 /* Update the variables to point into the current struct net 3572 * except for the first element flush 3573 */ 3574 for (i = 1; i < ARRAY_SIZE(ipv4_route_netns_table) - 1; i++) 3575 tbl[i].data += (void *)net - (void *)&init_net; 3576 } 3577 tbl[0].extra1 = net; 3578 3579 net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route", 3580 tbl, table_size); 3581 if (!net->ipv4.route_hdr) 3582 goto err_reg; 3583 return 0; 3584 3585err_reg: 3586 if (tbl != ipv4_route_netns_table) 3587 kfree(tbl); 3588err_dup: 3589 return -ENOMEM; 3590} 3591 3592static __net_exit void sysctl_route_net_exit(struct net *net) 3593{ 3594 struct ctl_table *tbl; 3595 3596 tbl = net->ipv4.route_hdr->ctl_table_arg; 3597 unregister_net_sysctl_table(net->ipv4.route_hdr); 3598 BUG_ON(tbl == ipv4_route_netns_table); 3599 kfree(tbl); 3600} 3601 3602static __net_initdata struct pernet_operations sysctl_route_ops = { 3603 .init = sysctl_route_net_init, 3604 .exit = sysctl_route_net_exit, 3605}; 3606#endif 3607 3608static __net_init int netns_ip_rt_init(struct net *net) 3609{ 3610 /* Set default value for namespaceified sysctls */ 3611 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU; 3612 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES; 3613 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS; 3614 return 0; 3615} 3616 3617static struct pernet_operations __net_initdata ip_rt_ops = { 3618 .init = netns_ip_rt_init, 3619}; 3620 3621static __net_init int rt_genid_init(struct net *net) 3622{ 3623 atomic_set(&net->ipv4.rt_genid, 0); 3624 atomic_set(&net->fnhe_genid, 0); 3625 atomic_set(&net->ipv4.dev_addr_genid, get_random_u32()); 3626 return 0; 3627} 3628 3629static __net_initdata struct pernet_operations rt_genid_ops = { 3630 .init = rt_genid_init, 3631}; 3632 3633static int __net_init ipv4_inetpeer_init(struct net *net) 3634{ 3635 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3636 3637 if (!bp) 3638 return -ENOMEM; 3639 inet_peer_base_init(bp); 3640 net->ipv4.peers = bp; 3641 return 0; 3642} 3643 3644static void __net_exit ipv4_inetpeer_exit(struct net *net) 3645{ 3646 struct inet_peer_base *bp = net->ipv4.peers; 3647 3648 net->ipv4.peers = NULL; 3649 inetpeer_invalidate_tree(bp); 3650 kfree(bp); 3651} 3652 3653static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3654 .init = ipv4_inetpeer_init, 3655 .exit = ipv4_inetpeer_exit, 3656}; 3657 3658#ifdef CONFIG_IP_ROUTE_CLASSID 3659struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3660#endif /* CONFIG_IP_ROUTE_CLASSID */ 3661 3662int __init ip_rt_init(void) 3663{ 3664 void *idents_hash; 3665 int cpu; 3666 3667 /* For modern hosts, this will use 2 MB of memory */ 3668 idents_hash = alloc_large_system_hash("IP idents", 3669 sizeof(*ip_idents) + sizeof(*ip_tstamps), 3670 0, 3671 16, /* one bucket per 64 KB */ 3672 HASH_ZERO, 3673 NULL, 3674 &ip_idents_mask, 3675 2048, 3676 256*1024); 3677 3678 ip_idents = idents_hash; 3679 3680 get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents)); 3681 3682 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents); 3683 3684 for_each_possible_cpu(cpu) { 3685 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3686 3687 INIT_LIST_HEAD(&ul->head); 3688 INIT_LIST_HEAD(&ul->quarantine); 3689 spin_lock_init(&ul->lock); 3690 } 3691#ifdef CONFIG_IP_ROUTE_CLASSID 3692 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3693 if (!ip_rt_acct) 3694 panic("IP: failed to allocate ip_rt_acct\n"); 3695#endif 3696 3697 ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable, 3698 SLAB_HWCACHE_ALIGN | SLAB_PANIC); 3699 3700 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3701 3702 if (dst_entries_init(&ipv4_dst_ops) < 0) 3703 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3704 3705 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3706 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3707 3708 ipv4_dst_ops.gc_thresh = ~0; 3709 ip_rt_max_size = INT_MAX; 3710 3711 devinet_init(); 3712 ip_fib_init(); 3713 3714 if (ip_rt_proc_init()) 3715 pr_err("Unable to create route proc files\n"); 3716#ifdef CONFIG_XFRM 3717 xfrm_init(); 3718 xfrm4_init(); 3719#endif 3720 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3721 RTNL_FLAG_DOIT_UNLOCKED); 3722 3723#ifdef CONFIG_SYSCTL 3724 register_pernet_subsys(&sysctl_route_ops); 3725#endif 3726 register_pernet_subsys(&ip_rt_ops); 3727 register_pernet_subsys(&rt_genid_ops); 3728 register_pernet_subsys(&ipv4_inetpeer_ops); 3729 return 0; 3730} 3731 3732#ifdef CONFIG_SYSCTL 3733/* 3734 * We really need to sanitize the damn ipv4 init order, then all 3735 * this nonsense will go away. 3736 */ 3737void __init ip_static_sysctl_init(void) 3738{ 3739 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3740} 3741#endif 3742