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