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/flow.h> 88 #include <net/inet_dscp.h> 89 #include <net/net_namespace.h> 90 #include <net/ip.h> 91 #include <net/route.h> 92 #include <net/inetpeer.h> 93 #include <net/sock.h> 94 #include <net/ip_fib.h> 95 #include <net/nexthop.h> 96 #include <net/tcp.h> 97 #include <net/icmp.h> 98 #include <net/xfrm.h> 99 #include <net/lwtunnel.h> 100 #include <net/netevent.h> 101 #include <net/rtnetlink.h> 102 #ifdef CONFIG_SYSCTL 103 #include <linux/sysctl.h> 104 #endif 105 #include <net/secure_seq.h> 106 #include <net/ip_tunnels.h> 107 108 #include "fib_lookup.h" 109 110 #define RT_GC_TIMEOUT (300*HZ) 111 112 #define DEFAULT_MIN_PMTU (512 + 20 + 20) 113 #define DEFAULT_MTU_EXPIRES (10 * 60 * HZ) 114 #define DEFAULT_MIN_ADVMSS 256 115 static int ip_rt_max_size; 116 static int ip_rt_redirect_number __read_mostly = 9; 117 static int ip_rt_redirect_load __read_mostly = HZ / 50; 118 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 119 static int ip_rt_error_cost __read_mostly = HZ; 120 static int ip_rt_error_burst __read_mostly = 5 * HZ; 121 122 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 123 124 /* 125 * Interface to generic destination cache. 126 */ 127 128 INDIRECT_CALLABLE_SCOPE 129 struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 130 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 131 INDIRECT_CALLABLE_SCOPE 132 unsigned int ipv4_mtu(const struct dst_entry *dst); 133 static void ipv4_negative_advice(struct sock *sk, 134 struct dst_entry *dst); 135 static void ipv4_link_failure(struct sk_buff *skb); 136 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 137 struct sk_buff *skb, u32 mtu, 138 bool confirm_neigh); 139 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 140 struct sk_buff *skb); 141 static void ipv4_dst_destroy(struct dst_entry *dst); 142 143 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 144 { 145 WARN_ON(1); 146 return NULL; 147 } 148 149 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 150 struct sk_buff *skb, 151 const void *daddr); 152 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 153 154 static struct dst_ops ipv4_dst_ops = { 155 .family = AF_INET, 156 .check = ipv4_dst_check, 157 .default_advmss = ipv4_default_advmss, 158 .mtu = ipv4_mtu, 159 .cow_metrics = ipv4_cow_metrics, 160 .destroy = ipv4_dst_destroy, 161 .negative_advice = ipv4_negative_advice, 162 .link_failure = ipv4_link_failure, 163 .update_pmtu = ip_rt_update_pmtu, 164 .redirect = ip_do_redirect, 165 .local_out = __ip_local_out, 166 .neigh_lookup = ipv4_neigh_lookup, 167 .confirm_neigh = ipv4_confirm_neigh, 168 }; 169 170 #define ECN_OR_COST(class) TC_PRIO_##class 171 172 const __u8 ip_tos2prio[16] = { 173 TC_PRIO_BESTEFFORT, 174 ECN_OR_COST(BESTEFFORT), 175 TC_PRIO_BESTEFFORT, 176 ECN_OR_COST(BESTEFFORT), 177 TC_PRIO_BULK, 178 ECN_OR_COST(BULK), 179 TC_PRIO_BULK, 180 ECN_OR_COST(BULK), 181 TC_PRIO_INTERACTIVE, 182 ECN_OR_COST(INTERACTIVE), 183 TC_PRIO_INTERACTIVE, 184 ECN_OR_COST(INTERACTIVE), 185 TC_PRIO_INTERACTIVE_BULK, 186 ECN_OR_COST(INTERACTIVE_BULK), 187 TC_PRIO_INTERACTIVE_BULK, 188 ECN_OR_COST(INTERACTIVE_BULK) 189 }; 190 EXPORT_SYMBOL(ip_tos2prio); 191 192 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 193 #ifndef CONFIG_PREEMPT_RT 194 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 195 #else 196 #define RT_CACHE_STAT_INC(field) this_cpu_inc(rt_cache_stat.field) 197 #endif 198 199 #ifdef CONFIG_PROC_FS 200 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 201 { 202 if (*pos) 203 return NULL; 204 return SEQ_START_TOKEN; 205 } 206 207 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 208 { 209 ++*pos; 210 return NULL; 211 } 212 213 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 214 { 215 } 216 217 static int rt_cache_seq_show(struct seq_file *seq, void *v) 218 { 219 if (v == SEQ_START_TOKEN) 220 seq_printf(seq, "%-127s\n", 221 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 222 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 223 "HHUptod\tSpecDst"); 224 return 0; 225 } 226 227 static const struct seq_operations rt_cache_seq_ops = { 228 .start = rt_cache_seq_start, 229 .next = rt_cache_seq_next, 230 .stop = rt_cache_seq_stop, 231 .show = rt_cache_seq_show, 232 }; 233 234 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 235 { 236 int cpu; 237 238 if (*pos == 0) 239 return SEQ_START_TOKEN; 240 241 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 242 if (!cpu_possible(cpu)) 243 continue; 244 *pos = cpu+1; 245 return &per_cpu(rt_cache_stat, cpu); 246 } 247 return NULL; 248 } 249 250 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 251 { 252 int cpu; 253 254 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 255 if (!cpu_possible(cpu)) 256 continue; 257 *pos = cpu+1; 258 return &per_cpu(rt_cache_stat, cpu); 259 } 260 (*pos)++; 261 return NULL; 262 263 } 264 265 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 266 { 267 268 } 269 270 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 271 { 272 struct rt_cache_stat *st = v; 273 274 if (v == SEQ_START_TOKEN) { 275 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"); 276 return 0; 277 } 278 279 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x " 280 "%08x %08x %08x %08x %08x %08x " 281 "%08x %08x %08x %08x\n", 282 dst_entries_get_slow(&ipv4_dst_ops), 283 0, /* st->in_hit */ 284 st->in_slow_tot, 285 st->in_slow_mc, 286 st->in_no_route, 287 st->in_brd, 288 st->in_martian_dst, 289 st->in_martian_src, 290 291 0, /* st->out_hit */ 292 st->out_slow_tot, 293 st->out_slow_mc, 294 295 0, /* st->gc_total */ 296 0, /* st->gc_ignored */ 297 0, /* st->gc_goal_miss */ 298 0, /* st->gc_dst_overflow */ 299 0, /* st->in_hlist_search */ 300 0 /* st->out_hlist_search */ 301 ); 302 return 0; 303 } 304 305 static const struct seq_operations rt_cpu_seq_ops = { 306 .start = rt_cpu_seq_start, 307 .next = rt_cpu_seq_next, 308 .stop = rt_cpu_seq_stop, 309 .show = rt_cpu_seq_show, 310 }; 311 312 #ifdef CONFIG_IP_ROUTE_CLASSID 313 static int rt_acct_proc_show(struct seq_file *m, void *v) 314 { 315 struct ip_rt_acct *dst, *src; 316 unsigned int i, j; 317 318 dst = kzalloc_objs(struct ip_rt_acct, 256); 319 if (!dst) 320 return -ENOMEM; 321 322 for_each_possible_cpu(i) { 323 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 324 for (j = 0; j < 256; j++) { 325 dst[j].o_bytes += src[j].o_bytes; 326 dst[j].o_packets += src[j].o_packets; 327 dst[j].i_bytes += src[j].i_bytes; 328 dst[j].i_packets += src[j].i_packets; 329 } 330 } 331 332 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 333 kfree(dst); 334 return 0; 335 } 336 #endif 337 338 static int __net_init ip_rt_do_proc_init(struct net *net) 339 { 340 struct proc_dir_entry *pde; 341 342 pde = proc_create_seq("rt_cache", 0444, net->proc_net, 343 &rt_cache_seq_ops); 344 if (!pde) 345 goto err1; 346 347 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat, 348 &rt_cpu_seq_ops); 349 if (!pde) 350 goto err2; 351 352 #ifdef CONFIG_IP_ROUTE_CLASSID 353 pde = proc_create_single("rt_acct", 0, net->proc_net, 354 rt_acct_proc_show); 355 if (!pde) 356 goto err3; 357 #endif 358 return 0; 359 360 #ifdef CONFIG_IP_ROUTE_CLASSID 361 err3: 362 remove_proc_entry("rt_cache", net->proc_net_stat); 363 #endif 364 err2: 365 remove_proc_entry("rt_cache", net->proc_net); 366 err1: 367 return -ENOMEM; 368 } 369 370 static void __net_exit ip_rt_do_proc_exit(struct net *net) 371 { 372 remove_proc_entry("rt_cache", net->proc_net_stat); 373 remove_proc_entry("rt_cache", net->proc_net); 374 #ifdef CONFIG_IP_ROUTE_CLASSID 375 remove_proc_entry("rt_acct", net->proc_net); 376 #endif 377 } 378 379 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 380 .init = ip_rt_do_proc_init, 381 .exit = ip_rt_do_proc_exit, 382 }; 383 384 static int __init ip_rt_proc_init(void) 385 { 386 return register_pernet_subsys(&ip_rt_proc_ops); 387 } 388 389 #else 390 static inline int ip_rt_proc_init(void) 391 { 392 return 0; 393 } 394 #endif /* CONFIG_PROC_FS */ 395 396 static inline bool rt_is_expired(const struct rtable *rth) 397 { 398 bool res; 399 400 rcu_read_lock(); 401 res = rth->rt_genid != rt_genid_ipv4(dev_net_rcu(rth->dst.dev)); 402 rcu_read_unlock(); 403 404 return res; 405 } 406 407 void rt_cache_flush(struct net *net) 408 { 409 rt_genid_bump_ipv4(net); 410 } 411 412 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 413 struct sk_buff *skb, 414 const void *daddr) 415 { 416 const struct rtable *rt = container_of(dst, struct rtable, dst); 417 struct net_device *dev; 418 struct neighbour *n; 419 420 rcu_read_lock(); 421 dev = dst_dev_rcu(dst); 422 if (likely(rt->rt_gw_family == AF_INET)) { 423 n = ip_neigh_gw4(dev, rt->rt_gw4); 424 } else if (rt->rt_gw_family == AF_INET6) { 425 n = ip_neigh_gw6(dev, &rt->rt_gw6); 426 } else { 427 __be32 pkey; 428 429 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 430 n = ip_neigh_gw4(dev, pkey); 431 } 432 433 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 434 n = NULL; 435 436 rcu_read_unlock(); 437 438 return n; 439 } 440 441 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 442 { 443 const struct rtable *rt = container_of(dst, struct rtable, dst); 444 struct net_device *dev = dst_dev(dst); 445 const __be32 *pkey = daddr; 446 447 if (rt->rt_gw_family == AF_INET) { 448 pkey = (const __be32 *)&rt->rt_gw4; 449 } else if (IS_ENABLED(CONFIG_IPV6) && rt->rt_gw_family == AF_INET6) { 450 return __ipv6_confirm_neigh(dev, &rt->rt_gw6); 451 } else if (!daddr || 452 (rt->rt_flags & 453 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 454 return; 455 } 456 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 457 } 458 459 /* Hash tables of size 2048..262144 depending on RAM size. 460 * Each bucket uses 8 bytes. 461 */ 462 static u32 ip_idents_mask __read_mostly; 463 static atomic_t *ip_idents __read_mostly; 464 static u32 *ip_tstamps __read_mostly; 465 466 /* In order to protect privacy, we add a perturbation to identifiers 467 * if one generator is seldom used. This makes hard for an attacker 468 * to infer how many packets were sent between two points in time. 469 */ 470 static u32 ip_idents_reserve(u32 hash, int segs) 471 { 472 u32 bucket, old, now = (u32)jiffies; 473 atomic_t *p_id; 474 u32 *p_tstamp; 475 u32 delta = 0; 476 477 bucket = hash & ip_idents_mask; 478 p_tstamp = ip_tstamps + bucket; 479 p_id = ip_idents + bucket; 480 old = READ_ONCE(*p_tstamp); 481 482 if (old != now && cmpxchg(p_tstamp, old, now) == old) 483 delta = get_random_u32_below(now - old); 484 485 /* If UBSAN reports an error there, please make sure your compiler 486 * supports -fno-strict-overflow before reporting it that was a bug 487 * in UBSAN, and it has been fixed in GCC-8. 488 */ 489 return atomic_add_return(segs + delta, p_id) - segs; 490 } 491 492 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 493 { 494 u32 hash, id; 495 496 /* Note the following code is not safe, but this is okay. */ 497 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 498 get_random_bytes(&net->ipv4.ip_id_key, 499 sizeof(net->ipv4.ip_id_key)); 500 501 hash = siphash_3u32((__force u32)iph->daddr, 502 (__force u32)iph->saddr, 503 iph->protocol, 504 &net->ipv4.ip_id_key); 505 id = ip_idents_reserve(hash, segs); 506 iph->id = htons(id); 507 } 508 EXPORT_SYMBOL(__ip_select_ident); 509 510 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 511 const struct sock *sk, const struct iphdr *iph, 512 int oif, __u8 tos, u8 prot, u32 mark, 513 int flow_flags) 514 { 515 __u8 scope = RT_SCOPE_UNIVERSE; 516 517 if (sk) { 518 oif = sk->sk_bound_dev_if; 519 mark = READ_ONCE(sk->sk_mark); 520 tos = ip_sock_rt_tos(sk); 521 scope = ip_sock_rt_scope(sk); 522 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW : 523 sk->sk_protocol; 524 } 525 526 flowi4_init_output(fl4, oif, mark, tos & INET_DSCP_MASK, scope, 527 prot, flow_flags, iph->daddr, iph->saddr, 0, 0, 528 sock_net_uid(net, sk)); 529 } 530 531 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 532 const struct sock *sk) 533 { 534 const struct net *net = dev_net(skb->dev); 535 const struct iphdr *iph = ip_hdr(skb); 536 int oif = skb->dev->ifindex; 537 u8 prot = iph->protocol; 538 u32 mark = skb->mark; 539 __u8 tos = iph->tos; 540 541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 542 } 543 544 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 545 { 546 const struct inet_sock *inet = inet_sk(sk); 547 const struct ip_options_rcu *inet_opt; 548 __be32 daddr = inet->inet_daddr; 549 550 rcu_read_lock(); 551 inet_opt = rcu_dereference(inet->inet_opt); 552 if (inet_opt && inet_opt->opt.srr) 553 daddr = inet_opt->opt.faddr; 554 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark), 555 ip_sock_rt_tos(sk), 556 ip_sock_rt_scope(sk), 557 inet_test_bit(HDRINCL, sk) ? 558 IPPROTO_RAW : sk->sk_protocol, 559 inet_sk_flowi_flags(sk), 560 daddr, inet->inet_saddr, 0, 0, 561 sk_uid(sk)); 562 rcu_read_unlock(); 563 } 564 565 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 566 const struct sk_buff *skb) 567 { 568 if (skb) 569 build_skb_flow_key(fl4, skb, sk); 570 else 571 build_sk_flow_key(fl4, sk); 572 } 573 574 static DEFINE_SPINLOCK(fnhe_lock); 575 576 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 577 { 578 struct rtable *rt; 579 580 rt = rcu_dereference(fnhe->fnhe_rth_input); 581 if (rt) { 582 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 583 dst_dev_put(&rt->dst); 584 dst_release(&rt->dst); 585 } 586 rt = rcu_dereference(fnhe->fnhe_rth_output); 587 if (rt) { 588 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 589 dst_dev_put(&rt->dst); 590 dst_release(&rt->dst); 591 } 592 } 593 594 static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash) 595 { 596 struct fib_nh_exception __rcu **fnhe_p, **oldest_p; 597 struct fib_nh_exception *fnhe, *oldest = NULL; 598 599 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) { 600 fnhe = rcu_dereference_protected(*fnhe_p, 601 lockdep_is_held(&fnhe_lock)); 602 if (!fnhe) 603 break; 604 if (!oldest || 605 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) { 606 oldest = fnhe; 607 oldest_p = fnhe_p; 608 } 609 } 610 611 /* Clear oldest->fnhe_daddr to prevent this fnhe from being 612 * rebound with new dsts in rt_bind_exception(). 613 */ 614 oldest->fnhe_daddr = 0; 615 fnhe_flush_routes(oldest); 616 *oldest_p = oldest->fnhe_next; 617 kfree_rcu(oldest, rcu); 618 } 619 620 static u32 fnhe_hashfun(__be32 daddr) 621 { 622 static siphash_aligned_key_t fnhe_hash_key; 623 u64 hval; 624 625 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key)); 626 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key); 627 return hash_64(hval, FNHE_HASH_SHIFT); 628 } 629 630 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 631 { 632 rt->rt_pmtu = fnhe->fnhe_pmtu; 633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 634 rt->dst.expires = fnhe->fnhe_expires; 635 636 if (fnhe->fnhe_gw) { 637 rt->rt_flags |= RTCF_REDIRECTED; 638 rt->rt_uses_gateway = 1; 639 rt->rt_gw_family = AF_INET; 640 rt->rt_gw4 = fnhe->fnhe_gw; 641 } 642 } 643 644 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 645 __be32 gw, u32 pmtu, bool lock, 646 unsigned long expires) 647 { 648 struct fnhe_hash_bucket *hash; 649 struct fib_nh_exception *fnhe; 650 struct rtable *rt; 651 u32 genid, hval; 652 unsigned int i; 653 int depth; 654 655 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 656 hval = fnhe_hashfun(daddr); 657 658 spin_lock_bh(&fnhe_lock); 659 660 hash = rcu_dereference(nhc->nhc_exceptions); 661 if (!hash) { 662 hash = kzalloc_objs(*hash, FNHE_HASH_SIZE, GFP_ATOMIC); 663 if (!hash) 664 goto out_unlock; 665 rcu_assign_pointer(nhc->nhc_exceptions, hash); 666 } 667 668 hash += hval; 669 670 depth = 0; 671 for (fnhe = rcu_dereference(hash->chain); fnhe; 672 fnhe = rcu_dereference(fnhe->fnhe_next)) { 673 if (fnhe->fnhe_daddr == daddr) 674 break; 675 depth++; 676 } 677 678 if (fnhe) { 679 if (fnhe->fnhe_genid != genid) 680 fnhe->fnhe_genid = genid; 681 if (gw) 682 fnhe->fnhe_gw = gw; 683 if (pmtu) { 684 fnhe->fnhe_pmtu = pmtu; 685 fnhe->fnhe_mtu_locked = lock; 686 } 687 fnhe->fnhe_expires = max(1UL, expires); 688 /* Update all cached dsts too */ 689 rt = rcu_dereference(fnhe->fnhe_rth_input); 690 if (rt) 691 fill_route_from_fnhe(rt, fnhe); 692 rt = rcu_dereference(fnhe->fnhe_rth_output); 693 if (rt) 694 fill_route_from_fnhe(rt, fnhe); 695 } else { 696 /* Randomize max depth to avoid some side channels attacks. */ 697 int max_depth = FNHE_RECLAIM_DEPTH + 698 get_random_u32_below(FNHE_RECLAIM_DEPTH); 699 700 while (depth > max_depth) { 701 fnhe_remove_oldest(hash); 702 depth--; 703 } 704 705 fnhe = kzalloc_obj(*fnhe, GFP_ATOMIC); 706 if (!fnhe) 707 goto out_unlock; 708 709 fnhe->fnhe_next = hash->chain; 710 711 fnhe->fnhe_genid = genid; 712 fnhe->fnhe_daddr = daddr; 713 fnhe->fnhe_gw = gw; 714 fnhe->fnhe_pmtu = pmtu; 715 fnhe->fnhe_mtu_locked = lock; 716 fnhe->fnhe_expires = max(1UL, expires); 717 718 rcu_assign_pointer(hash->chain, fnhe); 719 720 /* Exception created; mark the cached routes for the nexthop 721 * stale, so anyone caching it rechecks if this exception 722 * applies to them. 723 */ 724 rt = rcu_dereference(nhc->nhc_rth_input); 725 if (rt) 726 WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL); 727 728 for_each_possible_cpu(i) { 729 struct rtable __rcu **prt; 730 731 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 732 rt = rcu_dereference(*prt); 733 if (rt) 734 WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL); 735 } 736 } 737 738 fnhe->fnhe_stamp = jiffies; 739 740 out_unlock: 741 spin_unlock_bh(&fnhe_lock); 742 } 743 744 /* Update the PMTU of an exception when: 745 * - the new MTU of the first hop becomes smaller than the PMTU 746 * - the old MTU was the same as the PMTU, and it limited discovery of 747 * larger MTUs on the path. With that limit raised, we can now 748 * discover larger MTUs 749 * A special case is locked exceptions, for which the PMTU is smaller 750 * than the minimal accepted PMTU: 751 * - if the new MTU is greater than the PMTU, don't make any change 752 * - otherwise, unlock and set PMTU 753 * 754 * fnhe_lock keeps fnhe_pmtu and fnhe_mtu_locked consistent against 755 * update_or_create_fnhe(), which sets both under the same lock. 756 */ 757 void fnhe_update_pmtu(struct fib_nh_exception *fnhe, u32 new, u32 orig) 758 { 759 spin_lock_bh(&fnhe_lock); 760 761 if (fnhe->fnhe_mtu_locked) { 762 if (new <= fnhe->fnhe_pmtu) { 763 fnhe->fnhe_pmtu = new; 764 fnhe->fnhe_mtu_locked = false; 765 } 766 } else if (new < fnhe->fnhe_pmtu || orig == fnhe->fnhe_pmtu) { 767 fnhe->fnhe_pmtu = new; 768 } 769 770 spin_unlock_bh(&fnhe_lock); 771 } 772 773 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 774 bool kill_route) 775 { 776 __be32 new_gw = icmp_hdr(skb)->un.gateway; 777 __be32 old_gw = ip_hdr(skb)->saddr; 778 struct net_device *dev = skb->dev; 779 struct in_device *in_dev; 780 struct fib_result res; 781 struct neighbour *n; 782 struct net *net; 783 784 switch (icmp_hdr(skb)->code & 7) { 785 case ICMP_REDIR_NET: 786 case ICMP_REDIR_NETTOS: 787 case ICMP_REDIR_HOST: 788 case ICMP_REDIR_HOSTTOS: 789 break; 790 791 default: 792 return; 793 } 794 795 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 796 return; 797 798 in_dev = __in_dev_get_rcu(dev); 799 if (!in_dev) 800 return; 801 802 net = dev_net(dev); 803 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 804 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 805 ipv4_is_zeronet(new_gw)) 806 goto reject_redirect; 807 808 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 809 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 810 goto reject_redirect; 811 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 812 goto reject_redirect; 813 } else { 814 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 815 goto reject_redirect; 816 } 817 818 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw); 819 if (!n) 820 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 821 if (!IS_ERR(n)) { 822 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) { 823 neigh_event_send(n, NULL); 824 } else { 825 if (fib_lookup(net, fl4, &res, 0) == 0) { 826 struct fib_nh_common *nhc; 827 828 fib_select_path(net, &res, fl4, skb); 829 nhc = FIB_RES_NHC(res); 830 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 831 0, false, 832 jiffies + ip_rt_gc_timeout); 833 } 834 if (kill_route) 835 WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL); 836 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 837 } 838 neigh_release(n); 839 } 840 return; 841 842 reject_redirect: 843 #ifdef CONFIG_IP_ROUTE_VERBOSE 844 if (IN_DEV_LOG_MARTIANS(in_dev)) { 845 const struct iphdr *iph = (const struct iphdr *) skb->data; 846 __be32 daddr = iph->daddr; 847 __be32 saddr = iph->saddr; 848 849 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 850 " Advised path = %pI4 -> %pI4\n", 851 &old_gw, dev->name, &new_gw, 852 &saddr, &daddr); 853 } 854 #endif 855 ; 856 } 857 858 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 859 { 860 struct rtable *rt; 861 struct flowi4 fl4; 862 const struct iphdr *iph = (const struct iphdr *) skb->data; 863 struct net *net = dev_net(skb->dev); 864 int oif = skb->dev->ifindex; 865 u8 prot = iph->protocol; 866 u32 mark = skb->mark; 867 __u8 tos = iph->tos; 868 869 rt = dst_rtable(dst); 870 871 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 872 __ip_do_redirect(rt, skb, &fl4, true); 873 } 874 875 static void ipv4_negative_advice(struct sock *sk, 876 struct dst_entry *dst) 877 { 878 struct rtable *rt = dst_rtable(dst); 879 880 if ((READ_ONCE(dst->obsolete) > 0) || 881 (rt->rt_flags & RTCF_REDIRECTED) || 882 READ_ONCE(rt->dst.expires)) 883 sk_dst_reset(sk); 884 } 885 886 /* 887 * Algorithm: 888 * 1. The first ip_rt_redirect_number redirects are sent 889 * with exponential backoff, then we stop sending them at all, 890 * assuming that the host ignores our redirects. 891 * 2. If we did not see packets requiring redirects 892 * during ip_rt_redirect_silence, we assume that the host 893 * forgot redirected route and start to send redirects again. 894 * 895 * This algorithm is much cheaper and more intelligent than dumb load limiting 896 * in icmp.c. 897 * 898 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 899 * and "frag. need" (breaks PMTU discovery) in icmp.c. 900 */ 901 902 void ip_rt_send_redirect(struct sk_buff *skb) 903 { 904 struct rtable *rt = skb_rtable(skb); 905 struct in_device *in_dev; 906 struct inet_peer *peer; 907 struct net *net; 908 int log_martians; 909 int vif; 910 911 rcu_read_lock(); 912 in_dev = __in_dev_get_rcu(rt->dst.dev); 913 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 914 rcu_read_unlock(); 915 return; 916 } 917 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 918 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 919 920 net = dev_net(rt->dst.dev); 921 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif); 922 if (!peer) { 923 rcu_read_unlock(); 924 return; 925 } 926 927 /* No redirected packets during ip_rt_redirect_silence; 928 * reset the algorithm. 929 */ 930 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 931 peer->rate_tokens = 0; 932 peer->n_redirects = 0; 933 } 934 935 /* Too many ignored redirects; do not send anything 936 * set dst.rate_last to the last seen redirected packet. 937 */ 938 if (peer->n_redirects >= ip_rt_redirect_number) { 939 peer->rate_last = jiffies; 940 goto out_unlock; 941 } 942 943 /* Check for load limit; set rate_last to the latest sent 944 * redirect. 945 */ 946 if (peer->n_redirects == 0 || 947 time_after(jiffies, 948 (peer->rate_last + 949 (ip_rt_redirect_load << peer->n_redirects)))) { 950 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 951 952 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 953 peer->rate_last = jiffies; 954 ++peer->n_redirects; 955 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians && 956 peer->n_redirects == ip_rt_redirect_number) 957 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 958 &ip_hdr(skb)->saddr, inet_iif(skb), 959 &ip_hdr(skb)->daddr, &gw); 960 } 961 out_unlock: 962 rcu_read_unlock(); 963 } 964 965 static int ip_error(struct sk_buff *skb) 966 { 967 struct rtable *rt = skb_rtable(skb); 968 struct net_device *dev = skb->dev; 969 struct in_device *in_dev; 970 struct inet_peer *peer; 971 unsigned long now; 972 struct net *net; 973 SKB_DR(reason); 974 bool send; 975 int code; 976 977 if (netif_is_l3_master(skb->dev)) { 978 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 979 if (!dev) 980 goto out; 981 } 982 983 in_dev = __in_dev_get_rcu(dev); 984 985 /* IP on this device is disabled. */ 986 if (!in_dev) 987 goto out; 988 989 net = dev_net(rt->dst.dev); 990 if (!IN_DEV_FORWARD(in_dev)) { 991 switch (rt->dst.error) { 992 case EHOSTUNREACH: 993 SKB_DR_SET(reason, IP_INADDRERRORS); 994 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 995 break; 996 997 case ENETUNREACH: 998 SKB_DR_SET(reason, IP_INNOROUTES); 999 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 1000 break; 1001 } 1002 goto out; 1003 } 1004 1005 switch (rt->dst.error) { 1006 case EINVAL: 1007 default: 1008 goto out; 1009 case EHOSTUNREACH: 1010 code = ICMP_HOST_UNREACH; 1011 break; 1012 case ENETUNREACH: 1013 code = ICMP_NET_UNREACH; 1014 SKB_DR_SET(reason, IP_INNOROUTES); 1015 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 1016 break; 1017 case EACCES: 1018 code = ICMP_PKT_FILTERED; 1019 break; 1020 } 1021 1022 rcu_read_lock(); 1023 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1024 l3mdev_master_ifindex_rcu(skb->dev)); 1025 send = true; 1026 if (peer) { 1027 now = jiffies; 1028 peer->rate_tokens += now - peer->rate_last; 1029 if (peer->rate_tokens > ip_rt_error_burst) 1030 peer->rate_tokens = ip_rt_error_burst; 1031 peer->rate_last = now; 1032 if (peer->rate_tokens >= ip_rt_error_cost) 1033 peer->rate_tokens -= ip_rt_error_cost; 1034 else 1035 send = false; 1036 } 1037 rcu_read_unlock(); 1038 1039 if (send) 1040 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1041 1042 out: kfree_skb_reason(skb, reason); 1043 return 0; 1044 } 1045 1046 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1047 { 1048 struct dst_entry *dst = &rt->dst; 1049 struct fib_result res; 1050 bool lock = false; 1051 struct net *net; 1052 u32 old_mtu; 1053 1054 if (ip_mtu_locked(dst)) 1055 return; 1056 1057 old_mtu = ipv4_mtu(dst); 1058 if (old_mtu < mtu) 1059 return; 1060 1061 rcu_read_lock(); 1062 net = dst_dev_net_rcu(dst); 1063 if (mtu < net->ipv4.ip_rt_min_pmtu) { 1064 lock = true; 1065 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu); 1066 } 1067 1068 if (rt->rt_pmtu == mtu && !lock && 1069 time_before(jiffies, READ_ONCE(dst->expires) - 1070 net->ipv4.ip_rt_mtu_expires / 2)) 1071 goto out; 1072 1073 if (fib_lookup(net, fl4, &res, 0) == 0) { 1074 struct fib_nh_common *nhc; 1075 1076 fib_select_path(net, &res, fl4, NULL); 1077 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1078 if (fib_info_num_path(res.fi) > 1) { 1079 int nhsel; 1080 1081 for (nhsel = 0; nhsel < fib_info_num_path(res.fi); nhsel++) { 1082 nhc = fib_info_nhc(res.fi, nhsel); 1083 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1084 jiffies + net->ipv4.ip_rt_mtu_expires); 1085 } 1086 goto out; 1087 } 1088 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1089 nhc = FIB_RES_NHC(res); 1090 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1091 jiffies + net->ipv4.ip_rt_mtu_expires); 1092 } 1093 out: 1094 rcu_read_unlock(); 1095 } 1096 1097 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1098 struct sk_buff *skb, u32 mtu, 1099 bool confirm_neigh) 1100 { 1101 struct rtable *rt = dst_rtable(dst); 1102 struct flowi4 fl4; 1103 1104 ip_rt_build_flow_key(&fl4, sk, skb); 1105 1106 /* Don't make lookup fail for bridged encapsulations */ 1107 if (skb && netif_is_any_bridge_port(skb->dev)) 1108 fl4.flowi4_oif = 0; 1109 1110 __ip_rt_update_pmtu(rt, &fl4, mtu); 1111 } 1112 1113 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1114 int oif, u8 protocol) 1115 { 1116 const struct iphdr *iph = (const struct iphdr *)skb->data; 1117 struct flowi4 fl4; 1118 struct rtable *rt; 1119 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1120 1121 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark, 1122 0); 1123 rt = __ip_route_output_key(net, &fl4); 1124 if (!IS_ERR(rt)) { 1125 __ip_rt_update_pmtu(rt, &fl4, mtu); 1126 ip_rt_put(rt); 1127 } 1128 } 1129 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1130 1131 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1132 { 1133 const struct iphdr *iph = (const struct iphdr *)skb->data; 1134 struct flowi4 fl4; 1135 struct rtable *rt; 1136 1137 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1138 1139 if (!fl4.flowi4_mark) 1140 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1141 1142 rt = __ip_route_output_key(sock_net(sk), &fl4); 1143 if (!IS_ERR(rt)) { 1144 __ip_rt_update_pmtu(rt, &fl4, mtu); 1145 ip_rt_put(rt); 1146 } 1147 } 1148 1149 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1150 { 1151 const struct iphdr *iph = (const struct iphdr *)skb->data; 1152 struct flowi4 fl4; 1153 struct rtable *rt; 1154 struct dst_entry *odst = NULL; 1155 bool new = false; 1156 struct net *net = sock_net(sk); 1157 1158 bh_lock_sock(sk); 1159 1160 if (!ip_sk_accept_pmtu(sk)) 1161 goto out; 1162 1163 odst = sk_dst_get(sk); 1164 1165 if (sock_owned_by_user(sk) || !odst) { 1166 __ipv4_sk_update_pmtu(skb, sk, mtu); 1167 goto out; 1168 } 1169 1170 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1171 1172 rt = dst_rtable(odst); 1173 if (READ_ONCE(odst->obsolete) && !odst->ops->check(odst, 0)) { 1174 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1175 if (IS_ERR(rt)) 1176 goto out; 1177 1178 new = true; 1179 } 1180 1181 __ip_rt_update_pmtu(dst_rtable(xfrm_dst_path(&rt->dst)), &fl4, mtu); 1182 1183 if (!dst_check(&rt->dst, 0)) { 1184 if (new) 1185 dst_release(&rt->dst); 1186 1187 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1188 if (IS_ERR(rt)) 1189 goto out; 1190 1191 new = true; 1192 } 1193 1194 if (new) 1195 sk_dst_set(sk, &rt->dst); 1196 1197 out: 1198 bh_unlock_sock(sk); 1199 dst_release(odst); 1200 } 1201 1202 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1203 int oif, u8 protocol) 1204 { 1205 const struct iphdr *iph = (const struct iphdr *)skb->data; 1206 struct flowi4 fl4; 1207 struct rtable *rt; 1208 1209 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0); 1210 rt = __ip_route_output_key(net, &fl4); 1211 if (!IS_ERR(rt)) { 1212 __ip_do_redirect(rt, skb, &fl4, false); 1213 ip_rt_put(rt); 1214 } 1215 } 1216 EXPORT_SYMBOL_GPL(ipv4_redirect); 1217 1218 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1219 { 1220 const struct iphdr *iph = (const struct iphdr *)skb->data; 1221 struct flowi4 fl4; 1222 struct rtable *rt; 1223 struct net *net = sock_net(sk); 1224 1225 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1226 rt = __ip_route_output_key(net, &fl4); 1227 if (!IS_ERR(rt)) { 1228 __ip_do_redirect(rt, skb, &fl4, false); 1229 ip_rt_put(rt); 1230 } 1231 } 1232 1233 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst, 1234 u32 cookie) 1235 { 1236 struct rtable *rt = dst_rtable(dst); 1237 1238 /* All IPV4 dsts are created with ->obsolete set to the value 1239 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1240 * into this function always. 1241 * 1242 * When a PMTU/redirect information update invalidates a route, 1243 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1244 * DST_OBSOLETE_DEAD. 1245 */ 1246 if (READ_ONCE(dst->obsolete) != DST_OBSOLETE_FORCE_CHK || 1247 rt_is_expired(rt)) 1248 return NULL; 1249 return dst; 1250 } 1251 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check); 1252 1253 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1254 { 1255 struct inet_skb_parm parm; 1256 struct net_device *dev; 1257 int res; 1258 1259 /* Recompile ip options since IPCB may not be valid anymore. 1260 * Also check we have a reasonable ipv4 header. 1261 */ 1262 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1263 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1264 return; 1265 1266 memset(&parm, 0, sizeof(parm)); 1267 if (ip_hdr(skb)->ihl > 5) { 1268 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1269 return; 1270 parm.opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1271 1272 rcu_read_lock(); 1273 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev; 1274 res = __ip_options_compile(dev_net(dev), &parm.opt, skb, NULL); 1275 rcu_read_unlock(); 1276 1277 if (res) 1278 return; 1279 } 1280 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &parm); 1281 } 1282 1283 static void ipv4_link_failure(struct sk_buff *skb) 1284 { 1285 struct rtable *rt; 1286 1287 ipv4_send_dest_unreach(skb); 1288 1289 rt = skb_rtable(skb); 1290 if (rt) 1291 dst_set_expires(&rt->dst, 0); 1292 } 1293 1294 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1295 { 1296 pr_debug("%s: %pI4 -> %pI4, %s\n", 1297 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1298 skb->dev ? skb->dev->name : "?"); 1299 kfree_skb(skb); 1300 WARN_ON_ONCE(1); 1301 return 0; 1302 } 1303 1304 /* 1305 * We do not cache source address of outgoing interface, 1306 * because it is used only by IP RR, TS and SRR options, 1307 * so that it out of fast path. 1308 * 1309 * BTW remember: "addr" is allowed to be not aligned 1310 * in IP options! 1311 */ 1312 1313 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1314 { 1315 __be32 src; 1316 1317 if (rt_is_output_route(rt)) 1318 src = ip_hdr(skb)->saddr; 1319 else { 1320 struct fib_result res; 1321 struct iphdr *iph = ip_hdr(skb); 1322 struct flowi4 fl4 = { 1323 .daddr = iph->daddr, 1324 .saddr = iph->saddr, 1325 .flowi4_dscp = ip4h_dscp(iph), 1326 .flowi4_oif = rt->dst.dev->ifindex, 1327 .flowi4_iif = skb->dev->ifindex, 1328 .flowi4_mark = skb->mark, 1329 }; 1330 1331 rcu_read_lock(); 1332 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1333 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1334 else 1335 src = inet_select_addr(rt->dst.dev, 1336 rt_nexthop(rt, iph->daddr), 1337 RT_SCOPE_UNIVERSE); 1338 rcu_read_unlock(); 1339 } 1340 memcpy(addr, &src, 4); 1341 } 1342 1343 #ifdef CONFIG_IP_ROUTE_CLASSID 1344 static void set_class_tag(struct rtable *rt, u32 tag) 1345 { 1346 if (!(rt->dst.tclassid & 0xFFFF)) 1347 rt->dst.tclassid |= tag & 0xFFFF; 1348 if (!(rt->dst.tclassid & 0xFFFF0000)) 1349 rt->dst.tclassid |= tag & 0xFFFF0000; 1350 } 1351 #endif 1352 1353 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1354 { 1355 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1356 unsigned int advmss; 1357 struct net *net; 1358 1359 rcu_read_lock(); 1360 net = dst_dev_net_rcu(dst); 1361 advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1362 net->ipv4.ip_rt_min_advmss); 1363 rcu_read_unlock(); 1364 1365 return min(advmss, IPV4_MAX_PMTU - header_size); 1366 } 1367 1368 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst) 1369 { 1370 return ip_dst_mtu_maybe_forward(dst, false); 1371 } 1372 EXPORT_INDIRECT_CALLABLE(ipv4_mtu); 1373 1374 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1375 { 1376 struct fnhe_hash_bucket *hash; 1377 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1378 u32 hval = fnhe_hashfun(daddr); 1379 1380 spin_lock_bh(&fnhe_lock); 1381 1382 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1383 lockdep_is_held(&fnhe_lock)); 1384 hash += hval; 1385 1386 fnhe_p = &hash->chain; 1387 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1388 while (fnhe) { 1389 if (fnhe->fnhe_daddr == daddr) { 1390 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1391 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1392 /* set fnhe_daddr to 0 to ensure it won't bind with 1393 * new dsts in rt_bind_exception(). 1394 */ 1395 fnhe->fnhe_daddr = 0; 1396 fnhe_flush_routes(fnhe); 1397 kfree_rcu(fnhe, rcu); 1398 break; 1399 } 1400 fnhe_p = &fnhe->fnhe_next; 1401 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1402 lockdep_is_held(&fnhe_lock)); 1403 } 1404 1405 spin_unlock_bh(&fnhe_lock); 1406 } 1407 1408 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1409 __be32 daddr) 1410 { 1411 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1412 struct fib_nh_exception *fnhe; 1413 u32 hval; 1414 1415 if (!hash) 1416 return NULL; 1417 1418 hval = fnhe_hashfun(daddr); 1419 1420 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1421 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1422 if (fnhe->fnhe_daddr == daddr) { 1423 if (fnhe->fnhe_expires && 1424 time_after(jiffies, fnhe->fnhe_expires)) { 1425 ip_del_fnhe(nhc, daddr); 1426 break; 1427 } 1428 return fnhe; 1429 } 1430 } 1431 return NULL; 1432 } 1433 1434 /* MTU selection: 1435 * 1. mtu on route is locked - use it 1436 * 2. mtu from nexthop exception 1437 * 3. mtu from egress device 1438 */ 1439 1440 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1441 { 1442 struct fib_nh_common *nhc = res->nhc; 1443 struct net_device *dev = nhc->nhc_dev; 1444 struct fib_info *fi = res->fi; 1445 u32 mtu = 0; 1446 1447 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) || 1448 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1449 mtu = fi->fib_mtu; 1450 1451 if (likely(!mtu)) { 1452 struct fib_nh_exception *fnhe; 1453 1454 fnhe = find_exception(nhc, daddr); 1455 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1456 mtu = fnhe->fnhe_pmtu; 1457 } 1458 1459 if (likely(!mtu)) 1460 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1461 1462 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1463 } 1464 1465 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1466 __be32 daddr, const bool do_cache) 1467 { 1468 bool ret = false; 1469 1470 spin_lock_bh(&fnhe_lock); 1471 1472 if (daddr == fnhe->fnhe_daddr) { 1473 struct rtable __rcu **porig; 1474 struct rtable *orig; 1475 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1476 1477 if (rt_is_input_route(rt)) 1478 porig = &fnhe->fnhe_rth_input; 1479 else 1480 porig = &fnhe->fnhe_rth_output; 1481 orig = rcu_dereference(*porig); 1482 1483 if (fnhe->fnhe_genid != genid) { 1484 fnhe->fnhe_genid = genid; 1485 fnhe->fnhe_gw = 0; 1486 fnhe->fnhe_pmtu = 0; 1487 fnhe->fnhe_expires = 0; 1488 fnhe->fnhe_mtu_locked = false; 1489 fnhe_flush_routes(fnhe); 1490 orig = NULL; 1491 } 1492 fill_route_from_fnhe(rt, fnhe); 1493 if (!rt->rt_gw4) { 1494 rt->rt_gw4 = daddr; 1495 rt->rt_gw_family = AF_INET; 1496 } 1497 1498 if (do_cache) { 1499 dst_hold(&rt->dst); 1500 rcu_assign_pointer(*porig, rt); 1501 if (orig) { 1502 dst_dev_put(&orig->dst); 1503 dst_release(&orig->dst); 1504 } 1505 ret = true; 1506 } 1507 1508 fnhe->fnhe_stamp = jiffies; 1509 } 1510 spin_unlock_bh(&fnhe_lock); 1511 1512 return ret; 1513 } 1514 1515 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1516 { 1517 struct rtable *orig, *prev, **p; 1518 bool ret = true; 1519 1520 if (rt_is_input_route(rt)) { 1521 p = (struct rtable **)&nhc->nhc_rth_input; 1522 } else { 1523 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1524 } 1525 orig = *p; 1526 1527 /* hold dst before doing cmpxchg() to avoid race condition 1528 * on this dst 1529 */ 1530 dst_hold(&rt->dst); 1531 prev = cmpxchg(p, orig, rt); 1532 if (prev == orig) { 1533 if (orig) { 1534 rt_add_uncached_list(orig); 1535 dst_release(&orig->dst); 1536 } 1537 } else { 1538 dst_release(&rt->dst); 1539 ret = false; 1540 } 1541 1542 return ret; 1543 } 1544 1545 struct uncached_list { 1546 spinlock_t lock; 1547 struct list_head head; 1548 }; 1549 1550 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1551 1552 void rt_add_uncached_list(struct rtable *rt) 1553 { 1554 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1555 1556 rt->dst.rt_uncached_list = ul; 1557 1558 spin_lock_bh(&ul->lock); 1559 list_add_tail(&rt->dst.rt_uncached, &ul->head); 1560 spin_unlock_bh(&ul->lock); 1561 } 1562 1563 void rt_del_uncached_list(struct rtable *rt) 1564 { 1565 struct uncached_list *ul = rt->dst.rt_uncached_list; 1566 1567 if (ul) { 1568 spin_lock_bh(&ul->lock); 1569 list_del_init(&rt->dst.rt_uncached); 1570 spin_unlock_bh(&ul->lock); 1571 } 1572 } 1573 1574 static void ipv4_dst_destroy(struct dst_entry *dst) 1575 { 1576 ip_dst_metrics_put(dst); 1577 rt_del_uncached_list(dst_rtable(dst)); 1578 } 1579 1580 void rt_flush_dev(struct net_device *dev) 1581 { 1582 struct rtable *rt, *safe; 1583 int cpu; 1584 1585 for_each_possible_cpu(cpu) { 1586 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1587 1588 if (list_empty(&ul->head)) 1589 continue; 1590 1591 spin_lock_bh(&ul->lock); 1592 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) { 1593 if (rt->dst.dev != dev) 1594 continue; 1595 rt->dst.dev = blackhole_netdev; 1596 netdev_ref_replace(dev, blackhole_netdev, 1597 &rt->dst.dev_tracker, GFP_ATOMIC); 1598 list_del_init(&rt->dst.rt_uncached); 1599 } 1600 spin_unlock_bh(&ul->lock); 1601 } 1602 } 1603 1604 static bool rt_cache_valid(const struct rtable *rt) 1605 { 1606 return rt && 1607 READ_ONCE(rt->dst.obsolete) == DST_OBSOLETE_FORCE_CHK && 1608 !rt_is_expired(rt); 1609 } 1610 1611 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1612 const struct fib_result *res, 1613 struct fib_nh_exception *fnhe, 1614 struct fib_info *fi, u16 type, u32 itag, 1615 const bool do_cache) 1616 { 1617 bool cached = false; 1618 1619 if (fi) { 1620 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1621 1622 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1623 rt->rt_uses_gateway = 1; 1624 rt->rt_gw_family = nhc->nhc_gw_family; 1625 /* only INET and INET6 are supported */ 1626 if (likely(nhc->nhc_gw_family == AF_INET)) 1627 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1628 else 1629 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1630 } 1631 1632 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1633 1634 #ifdef CONFIG_IP_ROUTE_CLASSID 1635 if (nhc->nhc_family == AF_INET) { 1636 struct fib_nh *nh; 1637 1638 nh = container_of(nhc, struct fib_nh, nh_common); 1639 rt->dst.tclassid = nh->nh_tclassid; 1640 } 1641 #endif 1642 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1643 if (unlikely(fnhe)) 1644 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1645 else if (do_cache) 1646 cached = rt_cache_route(nhc, rt); 1647 if (unlikely(!cached)) { 1648 /* Routes we intend to cache in nexthop exception or 1649 * FIB nexthop have the DST_NOCACHE bit clear. 1650 * However, if we are unsuccessful at storing this 1651 * route into the cache we really need to set it. 1652 */ 1653 if (!rt->rt_gw4) { 1654 rt->rt_gw_family = AF_INET; 1655 rt->rt_gw4 = daddr; 1656 } 1657 rt_add_uncached_list(rt); 1658 } 1659 } else 1660 rt_add_uncached_list(rt); 1661 1662 #ifdef CONFIG_IP_ROUTE_CLASSID 1663 #ifdef CONFIG_IP_MULTIPLE_TABLES 1664 set_class_tag(rt, res->tclassid); 1665 #endif 1666 set_class_tag(rt, itag); 1667 #endif 1668 } 1669 1670 struct rtable *rt_dst_alloc(struct net_device *dev, 1671 unsigned int flags, u16 type, 1672 bool noxfrm) 1673 { 1674 struct rtable *rt; 1675 1676 rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK, 1677 (noxfrm ? DST_NOXFRM : 0)); 1678 1679 if (rt) { 1680 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1681 rt->rt_flags = flags; 1682 rt->rt_type = type; 1683 rt->rt_is_input = 0; 1684 rt->rt_iif = 0; 1685 rt->rt_pmtu = 0; 1686 rt->rt_mtu_locked = 0; 1687 rt->rt_uses_gateway = 0; 1688 rt->rt_gw_family = 0; 1689 rt->rt_gw4 = 0; 1690 1691 rt->dst.output = ip_output; 1692 if (flags & RTCF_LOCAL) 1693 rt->dst.input = ip_local_deliver; 1694 } 1695 1696 return rt; 1697 } 1698 EXPORT_SYMBOL(rt_dst_alloc); 1699 1700 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1701 { 1702 struct rtable *new_rt; 1703 1704 new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK, 1705 rt->dst.flags); 1706 1707 if (new_rt) { 1708 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1709 new_rt->rt_flags = rt->rt_flags; 1710 new_rt->rt_type = rt->rt_type; 1711 new_rt->rt_is_input = rt->rt_is_input; 1712 new_rt->rt_iif = rt->rt_iif; 1713 new_rt->rt_pmtu = rt->rt_pmtu; 1714 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1715 new_rt->rt_gw_family = rt->rt_gw_family; 1716 if (rt->rt_gw_family == AF_INET) 1717 new_rt->rt_gw4 = rt->rt_gw4; 1718 else if (rt->rt_gw_family == AF_INET6) 1719 new_rt->rt_gw6 = rt->rt_gw6; 1720 1721 new_rt->dst.input = READ_ONCE(rt->dst.input); 1722 new_rt->dst.output = READ_ONCE(rt->dst.output); 1723 new_rt->dst.error = rt->dst.error; 1724 new_rt->dst.lastuse = jiffies; 1725 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1726 } 1727 return new_rt; 1728 } 1729 1730 /* called in rcu_read_lock() section */ 1731 enum skb_drop_reason 1732 ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1733 dscp_t dscp, struct net_device *dev, 1734 struct in_device *in_dev, u32 *itag) 1735 { 1736 enum skb_drop_reason reason; 1737 1738 /* Primary sanity checks. */ 1739 if (!in_dev) 1740 return SKB_DROP_REASON_NOT_SPECIFIED; 1741 1742 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1743 return SKB_DROP_REASON_IP_INVALID_SOURCE; 1744 1745 if (skb->protocol != htons(ETH_P_IP)) 1746 return SKB_DROP_REASON_INVALID_PROTO; 1747 1748 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1749 return SKB_DROP_REASON_IP_LOCALNET; 1750 1751 if (ipv4_is_zeronet(saddr)) { 1752 if (!ipv4_is_local_multicast(daddr) && 1753 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1754 return SKB_DROP_REASON_IP_INVALID_SOURCE; 1755 } else { 1756 reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0, 1757 dev, in_dev, itag); 1758 if (reason) 1759 return reason; 1760 } 1761 return SKB_NOT_DROPPED_YET; 1762 } 1763 1764 /* called in rcu_read_lock() section */ 1765 static enum skb_drop_reason 1766 ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1767 dscp_t dscp, struct net_device *dev, int our) 1768 { 1769 struct in_device *in_dev = __in_dev_get_rcu(dev); 1770 unsigned int flags = RTCF_MULTICAST; 1771 enum skb_drop_reason reason; 1772 struct rtable *rth; 1773 u32 itag = 0; 1774 1775 reason = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev, 1776 &itag); 1777 if (reason) 1778 return reason; 1779 1780 if (our) 1781 flags |= RTCF_LOCAL; 1782 1783 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 1784 IPCB(skb)->flags |= IPSKB_NOPOLICY; 1785 1786 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1787 false); 1788 if (!rth) 1789 return SKB_DROP_REASON_NOMEM; 1790 1791 #ifdef CONFIG_IP_ROUTE_CLASSID 1792 rth->dst.tclassid = itag; 1793 #endif 1794 rth->dst.output = ip_rt_bug; 1795 rth->rt_is_input= 1; 1796 1797 #ifdef CONFIG_IP_MROUTE 1798 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1799 rth->dst.input = ip_mr_input; 1800 #endif 1801 RT_CACHE_STAT_INC(in_slow_mc); 1802 1803 skb_dst_drop(skb); 1804 skb_dst_set(skb, &rth->dst); 1805 return SKB_NOT_DROPPED_YET; 1806 } 1807 1808 1809 static void ip_handle_martian_source(struct net_device *dev, 1810 struct in_device *in_dev, 1811 struct sk_buff *skb, 1812 __be32 daddr, 1813 __be32 saddr) 1814 { 1815 RT_CACHE_STAT_INC(in_martian_src); 1816 #ifdef CONFIG_IP_ROUTE_VERBOSE 1817 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1818 /* 1819 * RFC1812 recommendation, if source is martian, 1820 * the only hint is MAC header. 1821 */ 1822 pr_warn("martian source (src=%pI4, dst=%pI4, dev=%s)\n", 1823 &saddr, &daddr, dev->name); 1824 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1825 print_hex_dump(KERN_WARNING, "ll header: ", 1826 DUMP_PREFIX_OFFSET, 16, 1, 1827 skb_mac_header(skb), 1828 dev->hard_header_len, false); 1829 } 1830 } 1831 #endif 1832 } 1833 1834 /* called in rcu_read_lock() section */ 1835 static enum skb_drop_reason 1836 __mkroute_input(struct sk_buff *skb, const struct fib_result *res, 1837 struct in_device *in_dev, __be32 daddr, 1838 __be32 saddr, dscp_t dscp) 1839 { 1840 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 1841 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1842 struct net_device *dev = nhc->nhc_dev; 1843 struct fib_nh_exception *fnhe; 1844 struct rtable *rth; 1845 int err; 1846 struct in_device *out_dev; 1847 bool do_cache; 1848 u32 itag = 0; 1849 1850 /* get a working reference to the output device */ 1851 out_dev = __in_dev_get_rcu(dev); 1852 if (!out_dev) { 1853 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1854 return reason; 1855 } 1856 1857 err = fib_validate_source(skb, saddr, daddr, dscp, FIB_RES_OIF(*res), 1858 in_dev->dev, in_dev, &itag); 1859 if (err < 0) { 1860 reason = -err; 1861 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1862 saddr); 1863 1864 goto cleanup; 1865 } 1866 1867 do_cache = res->fi && !itag; 1868 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1869 skb->protocol == htons(ETH_P_IP)) { 1870 __be32 gw; 1871 1872 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1873 if (IN_DEV_SHARED_MEDIA(out_dev) || 1874 inet_addr_onlink(out_dev, saddr, gw)) 1875 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1876 } 1877 1878 if (skb->protocol != htons(ETH_P_IP)) { 1879 /* Not IP (i.e. ARP). Do not create route, if it is 1880 * invalid for proxy arp. DNAT routes are always valid. 1881 * 1882 * Proxy arp feature have been extended to allow, ARP 1883 * replies back to the same interface, to support 1884 * Private VLAN switch technologies. See arp.c. 1885 */ 1886 if (out_dev == in_dev && 1887 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1888 reason = SKB_DROP_REASON_ARP_PVLAN_DISABLE; 1889 goto cleanup; 1890 } 1891 } 1892 1893 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 1894 IPCB(skb)->flags |= IPSKB_NOPOLICY; 1895 1896 fnhe = find_exception(nhc, daddr); 1897 if (do_cache) { 1898 if (fnhe) 1899 rth = rcu_dereference(fnhe->fnhe_rth_input); 1900 else 1901 rth = rcu_dereference(nhc->nhc_rth_input); 1902 if (rt_cache_valid(rth)) { 1903 skb_dst_set_noref(skb, &rth->dst); 1904 goto out; 1905 } 1906 } 1907 1908 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1909 IN_DEV_ORCONF(out_dev, NOXFRM)); 1910 if (!rth) { 1911 reason = SKB_DROP_REASON_NOMEM; 1912 goto cleanup; 1913 } 1914 1915 rth->rt_is_input = 1; 1916 RT_CACHE_STAT_INC(in_slow_tot); 1917 1918 rth->dst.input = ip_forward; 1919 1920 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1921 do_cache); 1922 lwtunnel_set_redirect(&rth->dst); 1923 skb_dst_set(skb, &rth->dst); 1924 out: 1925 reason = SKB_NOT_DROPPED_YET; 1926 cleanup: 1927 return reason; 1928 } 1929 1930 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1931 /* To make ICMP packets follow the right flow, the multipath hash is 1932 * calculated from the inner IP addresses. 1933 */ 1934 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1935 struct flow_keys *hash_keys) 1936 { 1937 const struct iphdr *outer_iph = ip_hdr(skb); 1938 const struct iphdr *key_iph = outer_iph; 1939 const struct iphdr *inner_iph; 1940 const struct icmphdr *icmph; 1941 struct iphdr _inner_iph; 1942 struct icmphdr _icmph; 1943 1944 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1945 goto out; 1946 1947 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1948 goto out; 1949 1950 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1951 &_icmph); 1952 if (!icmph) 1953 goto out; 1954 1955 if (!icmp_is_err(icmph->type)) 1956 goto out; 1957 1958 inner_iph = skb_header_pointer(skb, 1959 outer_iph->ihl * 4 + sizeof(_icmph), 1960 sizeof(_inner_iph), &_inner_iph); 1961 if (!inner_iph) 1962 goto out; 1963 1964 key_iph = inner_iph; 1965 out: 1966 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1967 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1968 } 1969 1970 static u32 fib_multipath_custom_hash_outer(const struct net *net, 1971 const struct sk_buff *skb, 1972 bool *p_has_inner) 1973 { 1974 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 1975 struct flow_keys keys, hash_keys; 1976 1977 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 1978 return 0; 1979 1980 memset(&hash_keys, 0, sizeof(hash_keys)); 1981 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP); 1982 1983 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1984 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 1985 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1986 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 1987 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1988 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 1989 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1990 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) 1991 hash_keys.ports.src = keys.ports.src; 1992 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 1993 hash_keys.ports.dst = keys.ports.dst; 1994 1995 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION); 1996 return fib_multipath_hash_from_keys(net, &hash_keys); 1997 } 1998 1999 static u32 fib_multipath_custom_hash_inner(const struct net *net, 2000 const struct sk_buff *skb, 2001 bool has_inner) 2002 { 2003 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 2004 struct flow_keys keys, hash_keys; 2005 2006 /* We assume the packet carries an encapsulation, but if none was 2007 * encountered during dissection of the outer flow, then there is no 2008 * point in calling the flow dissector again. 2009 */ 2010 if (!has_inner) 2011 return 0; 2012 2013 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK)) 2014 return 0; 2015 2016 memset(&hash_keys, 0, sizeof(hash_keys)); 2017 skb_flow_dissect_flow_keys(skb, &keys, 0); 2018 2019 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION)) 2020 return 0; 2021 2022 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 2023 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2024 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 2025 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 2026 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 2027 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 2028 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 2029 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 2030 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP) 2031 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 2032 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP) 2033 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 2034 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL) 2035 hash_keys.tags.flow_label = keys.tags.flow_label; 2036 } 2037 2038 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO) 2039 hash_keys.basic.ip_proto = keys.basic.ip_proto; 2040 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT) 2041 hash_keys.ports.src = keys.ports.src; 2042 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT) 2043 hash_keys.ports.dst = keys.ports.dst; 2044 2045 return fib_multipath_hash_from_keys(net, &hash_keys); 2046 } 2047 2048 static u32 fib_multipath_custom_hash_skb(const struct net *net, 2049 const struct sk_buff *skb) 2050 { 2051 u32 mhash, mhash_inner; 2052 bool has_inner = true; 2053 2054 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner); 2055 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner); 2056 2057 return jhash_2words(mhash, mhash_inner, 0); 2058 } 2059 2060 static u32 fib_multipath_custom_hash_fl4(const struct net *net, 2061 const struct flowi4 *fl4) 2062 { 2063 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields); 2064 struct flow_keys hash_keys; 2065 2066 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK)) 2067 return 0; 2068 2069 memset(&hash_keys, 0, sizeof(hash_keys)); 2070 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2071 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP) 2072 hash_keys.addrs.v4addrs.src = fl4->saddr; 2073 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP) 2074 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2075 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO) 2076 hash_keys.basic.ip_proto = fl4->flowi4_proto; 2077 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) { 2078 if (fl4->flowi4_flags & FLOWI_FLAG_ANY_SPORT) 2079 hash_keys.ports.src = (__force __be16)get_random_u16(); 2080 else 2081 hash_keys.ports.src = fl4->fl4_sport; 2082 } 2083 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT) 2084 hash_keys.ports.dst = fl4->fl4_dport; 2085 2086 return fib_multipath_hash_from_keys(net, &hash_keys); 2087 } 2088 2089 /* if skb is set it will be used and fl4 can be NULL */ 2090 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 2091 const struct sk_buff *skb, struct flow_keys *flkeys) 2092 { 2093 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 2094 struct flow_keys hash_keys; 2095 u32 mhash = 0; 2096 2097 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) { 2098 case 0: 2099 memset(&hash_keys, 0, sizeof(hash_keys)); 2100 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2101 if (skb) { 2102 ip_multipath_l3_keys(skb, &hash_keys); 2103 } else { 2104 hash_keys.addrs.v4addrs.src = fl4->saddr; 2105 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2106 } 2107 mhash = fib_multipath_hash_from_keys(net, &hash_keys); 2108 break; 2109 case 1: 2110 /* skb is currently provided only when forwarding */ 2111 if (skb) { 2112 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 2113 struct flow_keys keys; 2114 2115 /* short-circuit if we already have L4 hash present */ 2116 if (skb->l4_hash) 2117 return skb_get_hash_raw(skb) >> 1; 2118 2119 memset(&hash_keys, 0, sizeof(hash_keys)); 2120 2121 if (!flkeys) { 2122 skb_flow_dissect_flow_keys(skb, &keys, flag); 2123 flkeys = &keys; 2124 } 2125 2126 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2127 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 2128 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 2129 hash_keys.ports.src = flkeys->ports.src; 2130 hash_keys.ports.dst = flkeys->ports.dst; 2131 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 2132 } else { 2133 memset(&hash_keys, 0, sizeof(hash_keys)); 2134 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2135 hash_keys.addrs.v4addrs.src = fl4->saddr; 2136 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2137 if (fl4->flowi4_flags & FLOWI_FLAG_ANY_SPORT) 2138 hash_keys.ports.src = (__force __be16)get_random_u16(); 2139 else 2140 hash_keys.ports.src = fl4->fl4_sport; 2141 hash_keys.ports.dst = fl4->fl4_dport; 2142 hash_keys.basic.ip_proto = fl4->flowi4_proto; 2143 } 2144 mhash = fib_multipath_hash_from_keys(net, &hash_keys); 2145 break; 2146 case 2: 2147 memset(&hash_keys, 0, sizeof(hash_keys)); 2148 /* skb is currently provided only when forwarding */ 2149 if (skb) { 2150 struct flow_keys keys; 2151 2152 skb_flow_dissect_flow_keys(skb, &keys, 0); 2153 /* Inner can be v4 or v6 */ 2154 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 2155 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2156 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 2157 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 2158 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 2159 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 2160 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 2161 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 2162 hash_keys.tags.flow_label = keys.tags.flow_label; 2163 hash_keys.basic.ip_proto = keys.basic.ip_proto; 2164 } else { 2165 /* Same as case 0 */ 2166 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2167 ip_multipath_l3_keys(skb, &hash_keys); 2168 } 2169 } else { 2170 /* Same as case 0 */ 2171 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 2172 hash_keys.addrs.v4addrs.src = fl4->saddr; 2173 hash_keys.addrs.v4addrs.dst = fl4->daddr; 2174 } 2175 mhash = fib_multipath_hash_from_keys(net, &hash_keys); 2176 break; 2177 case 3: 2178 if (skb) 2179 mhash = fib_multipath_custom_hash_skb(net, skb); 2180 else 2181 mhash = fib_multipath_custom_hash_fl4(net, fl4); 2182 break; 2183 } 2184 2185 if (multipath_hash) 2186 mhash = jhash_2words(mhash, multipath_hash, 0); 2187 2188 return mhash >> 1; 2189 } 2190 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2191 2192 static enum skb_drop_reason 2193 ip_mkroute_input(struct sk_buff *skb, struct fib_result *res, 2194 struct in_device *in_dev, __be32 daddr, 2195 __be32 saddr, dscp_t dscp, struct flow_keys *hkeys) 2196 { 2197 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2198 if (res->fi && fib_info_num_path(res->fi) > 1) { 2199 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2200 2201 fib_select_multipath(res, h, NULL); 2202 IPCB(skb)->flags |= IPSKB_MULTIPATH; 2203 } 2204 #endif 2205 2206 /* create a routing cache entry */ 2207 return __mkroute_input(skb, res, in_dev, daddr, saddr, dscp); 2208 } 2209 2210 /* Implements all the saddr-related checks as ip_route_input_slow(), 2211 * assuming daddr is valid and the destination is not a local broadcast one. 2212 * Uses the provided hint instead of performing a route lookup. 2213 */ 2214 enum skb_drop_reason 2215 ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2216 dscp_t dscp, struct net_device *dev, 2217 const struct sk_buff *hint) 2218 { 2219 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 2220 struct in_device *in_dev = __in_dev_get_rcu(dev); 2221 struct rtable *rt = skb_rtable(hint); 2222 struct net *net = dev_net(dev); 2223 u32 tag = 0; 2224 2225 if (!in_dev) 2226 return reason; 2227 2228 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) { 2229 reason = SKB_DROP_REASON_IP_INVALID_SOURCE; 2230 goto martian_source; 2231 } 2232 2233 if (ipv4_is_zeronet(saddr)) { 2234 reason = SKB_DROP_REASON_IP_INVALID_SOURCE; 2235 goto martian_source; 2236 } 2237 2238 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) { 2239 reason = SKB_DROP_REASON_IP_LOCALNET; 2240 goto martian_source; 2241 } 2242 2243 if (!(rt->rt_flags & RTCF_LOCAL)) 2244 goto skip_validate_source; 2245 2246 reason = fib_validate_source_reason(skb, saddr, daddr, dscp, 0, dev, 2247 in_dev, &tag); 2248 if (reason) 2249 goto martian_source; 2250 2251 skip_validate_source: 2252 skb_dst_copy(skb, hint); 2253 return SKB_NOT_DROPPED_YET; 2254 2255 martian_source: 2256 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2257 return reason; 2258 } 2259 2260 /* get device for dst_alloc with local routes */ 2261 static struct net_device *ip_rt_get_dev(struct net *net, 2262 const struct fib_result *res) 2263 { 2264 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL; 2265 struct net_device *dev = NULL; 2266 2267 if (nhc) 2268 dev = l3mdev_master_dev_rcu(nhc->nhc_dev); 2269 2270 return dev ? : net->loopback_dev; 2271 } 2272 2273 /* 2274 * NOTE. We drop all the packets that has local source 2275 * addresses, because every properly looped back packet 2276 * must have correct destination already attached by output routine. 2277 * Changes in the enforced policies must be applied also to 2278 * ip_route_use_hint(). 2279 * 2280 * Such approach solves two big problems: 2281 * 1. Not simplex devices are handled properly. 2282 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2283 * called with rcu_read_lock() 2284 */ 2285 2286 static enum skb_drop_reason 2287 ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2288 dscp_t dscp, struct net_device *dev, 2289 struct fib_result *res) 2290 { 2291 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 2292 struct in_device *in_dev = __in_dev_get_rcu(dev); 2293 struct flow_keys *flkeys = NULL, _flkeys; 2294 struct net *net = dev_net(dev); 2295 struct ip_tunnel_info *tun_info; 2296 int err = -EINVAL; 2297 unsigned int flags = 0; 2298 u32 itag = 0; 2299 struct rtable *rth; 2300 struct flowi4 fl4; 2301 bool do_cache = true; 2302 2303 /* IP on this device is disabled. */ 2304 2305 if (!in_dev) 2306 goto out; 2307 2308 /* Check for the most weird martians, which can be not detected 2309 * by fib_lookup. 2310 */ 2311 2312 tun_info = skb_tunnel_info(skb); 2313 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2314 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2315 else 2316 fl4.flowi4_tun_key.tun_id = 0; 2317 skb_dst_drop(skb); 2318 2319 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) { 2320 reason = SKB_DROP_REASON_IP_INVALID_SOURCE; 2321 goto martian_source; 2322 } 2323 2324 res->fi = NULL; 2325 res->table = NULL; 2326 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2327 goto brd_input; 2328 2329 /* Accept zero addresses only to limited broadcast; 2330 * I even do not know to fix it or not. Waiting for complains :-) 2331 */ 2332 if (ipv4_is_zeronet(saddr)) { 2333 reason = SKB_DROP_REASON_IP_INVALID_SOURCE; 2334 goto martian_source; 2335 } 2336 2337 if (ipv4_is_zeronet(daddr)) { 2338 reason = SKB_DROP_REASON_IP_INVALID_DEST; 2339 goto martian_destination; 2340 } 2341 2342 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2343 * and call it once if daddr or/and saddr are loopback addresses 2344 */ 2345 if (ipv4_is_loopback(daddr)) { 2346 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) { 2347 reason = SKB_DROP_REASON_IP_LOCALNET; 2348 goto martian_destination; 2349 } 2350 } else if (ipv4_is_loopback(saddr)) { 2351 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) { 2352 reason = SKB_DROP_REASON_IP_LOCALNET; 2353 goto martian_source; 2354 } 2355 } 2356 2357 /* 2358 * Now we are ready to route packet. 2359 */ 2360 fl4.flowi4_l3mdev = 0; 2361 fl4.flowi4_oif = 0; 2362 fl4.flowi4_iif = dev->ifindex; 2363 fl4.flowi4_mark = skb->mark; 2364 fl4.flowi4_dscp = dscp; 2365 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2366 fl4.flowi4_flags = 0; 2367 fl4.daddr = daddr; 2368 fl4.saddr = saddr; 2369 fl4.flowi4_uid = sock_net_uid(net, NULL); 2370 fl4.flowi4_multipath_hash = 0; 2371 2372 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2373 flkeys = &_flkeys; 2374 } else { 2375 fl4.flowi4_proto = 0; 2376 fl4.fl4_sport = 0; 2377 fl4.fl4_dport = 0; 2378 } 2379 2380 err = fib_lookup(net, &fl4, res, 0); 2381 if (err != 0) { 2382 if (!IN_DEV_FORWARD(in_dev)) 2383 err = -EHOSTUNREACH; 2384 goto no_route; 2385 } 2386 2387 if (res->type == RTN_BROADCAST) { 2388 if (IN_DEV_BFORWARD(in_dev)) 2389 goto make_route; 2390 /* not do cache if bc_forwarding is enabled */ 2391 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING)) 2392 do_cache = false; 2393 goto brd_input; 2394 } 2395 2396 err = -EINVAL; 2397 if (res->type == RTN_LOCAL) { 2398 reason = fib_validate_source_reason(skb, saddr, daddr, dscp, 2399 0, dev, in_dev, &itag); 2400 if (reason) 2401 goto martian_source; 2402 goto local_input; 2403 } 2404 2405 if (!IN_DEV_FORWARD(in_dev)) { 2406 err = -EHOSTUNREACH; 2407 goto no_route; 2408 } 2409 if (res->type != RTN_UNICAST) { 2410 reason = SKB_DROP_REASON_IP_INVALID_DEST; 2411 goto martian_destination; 2412 } 2413 2414 make_route: 2415 reason = ip_mkroute_input(skb, res, in_dev, daddr, saddr, dscp, 2416 flkeys); 2417 2418 out: 2419 return reason; 2420 2421 brd_input: 2422 if (skb->protocol != htons(ETH_P_IP)) { 2423 reason = SKB_DROP_REASON_INVALID_PROTO; 2424 goto out; 2425 } 2426 2427 if (!ipv4_is_zeronet(saddr)) { 2428 reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0, 2429 dev, in_dev, &itag); 2430 if (reason) 2431 goto martian_source; 2432 } 2433 flags |= RTCF_BROADCAST; 2434 res->type = RTN_BROADCAST; 2435 RT_CACHE_STAT_INC(in_brd); 2436 2437 local_input: 2438 if (IN_DEV_ORCONF(in_dev, NOPOLICY)) 2439 IPCB(skb)->flags |= IPSKB_NOPOLICY; 2440 2441 do_cache &= res->fi && !itag; 2442 if (do_cache) { 2443 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2444 2445 rth = rcu_dereference(nhc->nhc_rth_input); 2446 if (rt_cache_valid(rth)) { 2447 skb_dst_set_noref(skb, &rth->dst); 2448 reason = SKB_NOT_DROPPED_YET; 2449 goto out; 2450 } 2451 } 2452 2453 rth = rt_dst_alloc(ip_rt_get_dev(net, res), 2454 flags | RTCF_LOCAL, res->type, false); 2455 if (!rth) 2456 goto e_nobufs; 2457 2458 rth->dst.output= ip_rt_bug; 2459 #ifdef CONFIG_IP_ROUTE_CLASSID 2460 rth->dst.tclassid = itag; 2461 #endif 2462 rth->rt_is_input = 1; 2463 2464 RT_CACHE_STAT_INC(in_slow_tot); 2465 if (res->type == RTN_UNREACHABLE) { 2466 rth->dst.input= ip_error; 2467 rth->dst.error= -err; 2468 rth->rt_flags &= ~RTCF_LOCAL; 2469 } 2470 2471 if (do_cache) { 2472 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2473 2474 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2475 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2476 WARN_ON(rth->dst.input == lwtunnel_input); 2477 rth->dst.lwtstate->orig_input = rth->dst.input; 2478 rth->dst.input = lwtunnel_input; 2479 } 2480 2481 if (unlikely(!rt_cache_route(nhc, rth))) 2482 rt_add_uncached_list(rth); 2483 } 2484 skb_dst_set(skb, &rth->dst); 2485 reason = SKB_NOT_DROPPED_YET; 2486 goto out; 2487 2488 no_route: 2489 RT_CACHE_STAT_INC(in_no_route); 2490 res->type = RTN_UNREACHABLE; 2491 res->fi = NULL; 2492 res->table = NULL; 2493 goto local_input; 2494 2495 /* 2496 * Do not cache martian addresses: they should be logged (RFC1812) 2497 */ 2498 martian_destination: 2499 RT_CACHE_STAT_INC(in_martian_dst); 2500 #ifdef CONFIG_IP_ROUTE_VERBOSE 2501 if (IN_DEV_LOG_MARTIANS(in_dev)) 2502 net_warn_ratelimited("martian destination (src=%pI4, dst=%pI4, dev=%s)\n", 2503 &saddr, &daddr, dev->name); 2504 #endif 2505 goto out; 2506 2507 e_nobufs: 2508 reason = SKB_DROP_REASON_NOMEM; 2509 goto out; 2510 2511 martian_source: 2512 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2513 goto out; 2514 } 2515 2516 /* called with rcu_read_lock held */ 2517 static enum skb_drop_reason 2518 ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2519 dscp_t dscp, struct net_device *dev, 2520 struct fib_result *res) 2521 { 2522 /* Multicast recognition logic is moved from route cache to here. 2523 * The problem was that too many Ethernet cards have broken/missing 2524 * hardware multicast filters :-( As result the host on multicasting 2525 * network acquires a lot of useless route cache entries, sort of 2526 * SDR messages from all the world. Now we try to get rid of them. 2527 * Really, provided software IP multicast filter is organized 2528 * reasonably (at least, hashed), it does not result in a slowdown 2529 * comparing with route cache reject entries. 2530 * Note, that multicast routers are not affected, because 2531 * route cache entry is created eventually. 2532 */ 2533 if (ipv4_is_multicast(daddr)) { 2534 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 2535 struct in_device *in_dev = __in_dev_get_rcu(dev); 2536 int our = 0; 2537 2538 if (!in_dev) 2539 return reason; 2540 2541 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2542 ip_hdr(skb)->protocol); 2543 2544 /* check l3 master if no match yet */ 2545 if (!our && netif_is_l3_slave(dev)) { 2546 struct in_device *l3_in_dev; 2547 2548 l3_in_dev = __in_dev_get_rcu(skb->dev); 2549 if (l3_in_dev) 2550 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2551 ip_hdr(skb)->protocol); 2552 } 2553 2554 if (our 2555 #ifdef CONFIG_IP_MROUTE 2556 || 2557 (!ipv4_is_local_multicast(daddr) && 2558 IN_DEV_MFORWARD(in_dev)) 2559 #endif 2560 ) { 2561 reason = ip_route_input_mc(skb, daddr, saddr, dscp, 2562 dev, our); 2563 } 2564 return reason; 2565 } 2566 2567 return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res); 2568 } 2569 2570 enum skb_drop_reason ip_route_input_noref(struct sk_buff *skb, __be32 daddr, 2571 __be32 saddr, dscp_t dscp, 2572 struct net_device *dev) 2573 { 2574 enum skb_drop_reason reason; 2575 struct fib_result res; 2576 2577 rcu_read_lock(); 2578 reason = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res); 2579 rcu_read_unlock(); 2580 2581 return reason; 2582 } 2583 EXPORT_SYMBOL(ip_route_input_noref); 2584 2585 /* called with rcu_read_lock() */ 2586 static struct rtable *__mkroute_output(const struct fib_result *res, 2587 const struct flowi4 *fl4, int orig_oif, 2588 struct net_device *dev_out, 2589 unsigned int flags) 2590 { 2591 struct fib_info *fi = res->fi; 2592 struct fib_nh_exception *fnhe; 2593 struct in_device *in_dev; 2594 u16 type = res->type; 2595 struct rtable *rth; 2596 bool do_cache; 2597 2598 in_dev = __in_dev_get_rcu(dev_out); 2599 if (!in_dev) 2600 return ERR_PTR(-EINVAL); 2601 2602 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2603 if (ipv4_is_loopback(fl4->saddr) && 2604 !(dev_out->flags & IFF_LOOPBACK) && 2605 !netif_is_l3_master(dev_out)) 2606 return ERR_PTR(-EINVAL); 2607 2608 if (ipv4_is_lbcast(fl4->daddr)) { 2609 type = RTN_BROADCAST; 2610 2611 /* reset fi to prevent gateway resolution */ 2612 fi = NULL; 2613 } else if (ipv4_is_multicast(fl4->daddr)) { 2614 type = RTN_MULTICAST; 2615 } else if (ipv4_is_zeronet(fl4->daddr)) { 2616 return ERR_PTR(-EINVAL); 2617 } 2618 2619 if (dev_out->flags & IFF_LOOPBACK) 2620 flags |= RTCF_LOCAL; 2621 2622 do_cache = true; 2623 if (type == RTN_BROADCAST) { 2624 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2625 } else if (type == RTN_MULTICAST) { 2626 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2627 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2628 fl4->flowi4_proto)) 2629 flags &= ~RTCF_LOCAL; 2630 else 2631 do_cache = false; 2632 /* If multicast route do not exist use 2633 * default one, but do not gateway in this case. 2634 * Yes, it is hack. 2635 */ 2636 if (fi && res->prefixlen < 4) 2637 fi = NULL; 2638 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2639 (orig_oif != dev_out->ifindex)) { 2640 /* For local routes that require a particular output interface 2641 * we do not want to cache the result. Caching the result 2642 * causes incorrect behaviour when there are multiple source 2643 * addresses on the interface, the end result being that if the 2644 * intended recipient is waiting on that interface for the 2645 * packet he won't receive it because it will be delivered on 2646 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2647 * be set to the loopback interface as well. 2648 */ 2649 do_cache = false; 2650 } 2651 2652 fnhe = NULL; 2653 do_cache &= fi != NULL; 2654 if (fi) { 2655 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2656 struct rtable __rcu **prth; 2657 2658 fnhe = find_exception(nhc, fl4->daddr); 2659 if (!do_cache) 2660 goto add; 2661 if (fnhe) { 2662 prth = &fnhe->fnhe_rth_output; 2663 } else { 2664 if (unlikely(fl4->flowi4_flags & 2665 FLOWI_FLAG_KNOWN_NH && 2666 !(nhc->nhc_gw_family && 2667 nhc->nhc_scope == RT_SCOPE_LINK))) { 2668 do_cache = false; 2669 goto add; 2670 } 2671 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2672 } 2673 rth = rcu_dereference(*prth); 2674 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2675 return rth; 2676 } 2677 2678 add: 2679 rth = rt_dst_alloc(dev_out, flags, type, 2680 IN_DEV_ORCONF(in_dev, NOXFRM)); 2681 if (!rth) 2682 return ERR_PTR(-ENOBUFS); 2683 2684 rth->rt_iif = orig_oif; 2685 2686 RT_CACHE_STAT_INC(out_slow_tot); 2687 2688 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2689 if (flags & RTCF_LOCAL && 2690 !(dev_out->flags & IFF_LOOPBACK)) { 2691 rth->dst.output = ip_mc_output; 2692 RT_CACHE_STAT_INC(out_slow_mc); 2693 } 2694 #ifdef CONFIG_IP_MROUTE 2695 if (type == RTN_MULTICAST) { 2696 if (IN_DEV_MFORWARD(in_dev) && 2697 !ipv4_is_local_multicast(fl4->daddr)) { 2698 rth->dst.input = ip_mr_input; 2699 rth->dst.output = ip_mr_output; 2700 } 2701 } 2702 #endif 2703 } 2704 2705 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2706 lwtunnel_set_redirect(&rth->dst); 2707 2708 return rth; 2709 } 2710 2711 /* 2712 * Major route resolver routine. 2713 */ 2714 2715 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2716 const struct sk_buff *skb) 2717 { 2718 struct fib_result res = { 2719 .type = RTN_UNSPEC, 2720 .fi = NULL, 2721 .table = NULL, 2722 .tclassid = 0, 2723 }; 2724 struct rtable *rth; 2725 2726 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2727 2728 rcu_read_lock(); 2729 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2730 rcu_read_unlock(); 2731 2732 return rth; 2733 } 2734 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2735 2736 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2737 struct fib_result *res, 2738 const struct sk_buff *skb) 2739 { 2740 struct net_device *dev_out = NULL; 2741 int orig_oif = fl4->flowi4_oif; 2742 unsigned int flags = 0; 2743 struct rtable *rth; 2744 int err; 2745 2746 if (fl4->saddr) { 2747 if (ipv4_is_multicast(fl4->saddr) || 2748 ipv4_is_lbcast(fl4->saddr)) { 2749 rth = ERR_PTR(-EINVAL); 2750 goto out; 2751 } 2752 2753 rth = ERR_PTR(-ENETUNREACH); 2754 2755 /* I removed check for oif == dev_out->oif here. 2756 * It was wrong for two reasons: 2757 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2758 * is assigned to multiple interfaces. 2759 * 2. Moreover, we are allowed to send packets with saddr 2760 * of another iface. --ANK 2761 */ 2762 2763 if (fl4->flowi4_oif == 0 && 2764 (ipv4_is_multicast(fl4->daddr) || 2765 ipv4_is_lbcast(fl4->daddr))) { 2766 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2767 dev_out = __ip_dev_find(net, fl4->saddr, false); 2768 if (!dev_out) 2769 goto out; 2770 2771 /* Special hack: user can direct multicasts 2772 * and limited broadcast via necessary interface 2773 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2774 * This hack is not just for fun, it allows 2775 * vic,vat and friends to work. 2776 * They bind socket to loopback, set ttl to zero 2777 * and expect that it will work. 2778 * From the viewpoint of routing cache they are broken, 2779 * because we are not allowed to build multicast path 2780 * with loopback source addr (look, routing cache 2781 * cannot know, that ttl is zero, so that packet 2782 * will not leave this host and route is valid). 2783 * Luckily, this hack is good workaround. 2784 */ 2785 2786 fl4->flowi4_oif = dev_out->ifindex; 2787 goto make_route; 2788 } 2789 2790 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2791 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2792 if (!__ip_dev_find(net, fl4->saddr, false)) 2793 goto out; 2794 } 2795 } 2796 2797 2798 if (fl4->flowi4_oif) { 2799 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2800 rth = ERR_PTR(-ENODEV); 2801 if (!dev_out) 2802 goto out; 2803 2804 /* RACE: Check return value of inet_select_addr instead. */ 2805 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2806 rth = ERR_PTR(-ENETUNREACH); 2807 goto out; 2808 } 2809 if (ipv4_is_local_multicast(fl4->daddr) || 2810 ipv4_is_lbcast(fl4->daddr) || 2811 fl4->flowi4_proto == IPPROTO_IGMP) { 2812 if (!fl4->saddr) 2813 fl4->saddr = inet_select_addr(dev_out, 0, 2814 RT_SCOPE_LINK); 2815 goto make_route; 2816 } 2817 if (!fl4->saddr) { 2818 if (ipv4_is_multicast(fl4->daddr)) 2819 fl4->saddr = inet_select_addr(dev_out, 0, 2820 fl4->flowi4_scope); 2821 else if (!fl4->daddr) 2822 fl4->saddr = inet_select_addr(dev_out, 0, 2823 RT_SCOPE_HOST); 2824 } 2825 } 2826 2827 if (!fl4->daddr) { 2828 fl4->daddr = fl4->saddr; 2829 if (!fl4->daddr) 2830 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2831 dev_out = net->loopback_dev; 2832 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2833 res->type = RTN_LOCAL; 2834 flags |= RTCF_LOCAL; 2835 goto make_route; 2836 } 2837 2838 err = fib_lookup(net, fl4, res, 0); 2839 if (err) { 2840 res->fi = NULL; 2841 res->table = NULL; 2842 if (fl4->flowi4_oif && 2843 (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) { 2844 /* Apparently, routing tables are wrong. Assume, 2845 * that the destination is on link. 2846 * 2847 * WHY? DW. 2848 * Because we are allowed to send to iface 2849 * even if it has NO routes and NO assigned 2850 * addresses. When oif is specified, routing 2851 * tables are looked up with only one purpose: 2852 * to catch if destination is gatewayed, rather than 2853 * direct. Moreover, if MSG_DONTROUTE is set, 2854 * we send packet, ignoring both routing tables 2855 * and ifaddr state. --ANK 2856 * 2857 * 2858 * We could make it even if oif is unknown, 2859 * likely IPv6, but we do not. 2860 */ 2861 2862 if (fl4->saddr == 0) 2863 fl4->saddr = inet_select_addr(dev_out, 0, 2864 RT_SCOPE_LINK); 2865 res->type = RTN_UNICAST; 2866 goto make_route; 2867 } 2868 rth = ERR_PTR(err); 2869 goto out; 2870 } 2871 2872 if (res->type == RTN_LOCAL) { 2873 if (!fl4->saddr) { 2874 if (res->fi->fib_prefsrc) 2875 fl4->saddr = res->fi->fib_prefsrc; 2876 else 2877 fl4->saddr = fl4->daddr; 2878 } 2879 2880 /* L3 master device is the loopback for that domain */ 2881 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2882 net->loopback_dev; 2883 2884 /* make sure orig_oif points to fib result device even 2885 * though packet rx/tx happens over loopback or l3mdev 2886 */ 2887 orig_oif = FIB_RES_OIF(*res); 2888 2889 fl4->flowi4_oif = dev_out->ifindex; 2890 flags |= RTCF_LOCAL; 2891 goto make_route; 2892 } 2893 2894 fib_select_path(net, res, fl4, skb); 2895 2896 dev_out = FIB_RES_DEV(*res); 2897 2898 make_route: 2899 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2900 2901 out: 2902 return rth; 2903 } 2904 2905 static struct dst_ops ipv4_dst_blackhole_ops = { 2906 .family = AF_INET, 2907 .default_advmss = ipv4_default_advmss, 2908 .neigh_lookup = ipv4_neigh_lookup, 2909 .check = dst_blackhole_check, 2910 .cow_metrics = dst_blackhole_cow_metrics, 2911 .update_pmtu = dst_blackhole_update_pmtu, 2912 .redirect = dst_blackhole_redirect, 2913 .mtu = dst_blackhole_mtu, 2914 }; 2915 2916 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2917 { 2918 struct rtable *ort = dst_rtable(dst_orig); 2919 struct rtable *rt; 2920 2921 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0); 2922 if (rt) { 2923 struct dst_entry *new = &rt->dst; 2924 2925 new->__use = 1; 2926 new->input = dst_discard; 2927 new->output = dst_discard_out; 2928 2929 new->dev = net->loopback_dev; 2930 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC); 2931 2932 rt->rt_is_input = ort->rt_is_input; 2933 rt->rt_iif = ort->rt_iif; 2934 rt->rt_pmtu = ort->rt_pmtu; 2935 rt->rt_mtu_locked = ort->rt_mtu_locked; 2936 2937 rt->rt_genid = rt_genid_ipv4(net); 2938 rt->rt_flags = ort->rt_flags; 2939 rt->rt_type = ort->rt_type; 2940 rt->rt_uses_gateway = ort->rt_uses_gateway; 2941 rt->rt_gw_family = ort->rt_gw_family; 2942 if (rt->rt_gw_family == AF_INET) 2943 rt->rt_gw4 = ort->rt_gw4; 2944 else if (rt->rt_gw_family == AF_INET6) 2945 rt->rt_gw6 = ort->rt_gw6; 2946 } 2947 2948 dst_release(dst_orig); 2949 2950 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2951 } 2952 2953 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2954 const struct sock *sk) 2955 { 2956 struct rtable *rt = __ip_route_output_key(net, flp4); 2957 2958 if (IS_ERR(rt)) 2959 return rt; 2960 2961 if (flp4->flowi4_proto) { 2962 flp4->flowi4_oif = rt->dst.dev->ifindex; 2963 rt = dst_rtable(xfrm_lookup_route(net, &rt->dst, 2964 flowi4_to_flowi(flp4), 2965 sk, 0)); 2966 } 2967 2968 return rt; 2969 } 2970 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2971 2972 /* called with rcu_read_lock held */ 2973 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2974 struct rtable *rt, u32 table_id, dscp_t dscp, 2975 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2976 u32 seq, unsigned int flags) 2977 { 2978 struct rtmsg *r; 2979 struct nlmsghdr *nlh; 2980 unsigned long expires = 0; 2981 u32 error; 2982 u32 metrics[RTAX_MAX]; 2983 2984 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2985 if (!nlh) 2986 return -EMSGSIZE; 2987 2988 r = nlmsg_data(nlh); 2989 r->rtm_family = AF_INET; 2990 r->rtm_dst_len = 32; 2991 r->rtm_src_len = 0; 2992 r->rtm_tos = inet_dscp_to_dsfield(dscp); 2993 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2994 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2995 goto nla_put_failure; 2996 r->rtm_type = rt->rt_type; 2997 r->rtm_scope = RT_SCOPE_UNIVERSE; 2998 r->rtm_protocol = RTPROT_UNSPEC; 2999 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 3000 if (rt->rt_flags & RTCF_NOTIFY) 3001 r->rtm_flags |= RTM_F_NOTIFY; 3002 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 3003 r->rtm_flags |= RTCF_DOREDIRECT; 3004 3005 if (nla_put_in_addr(skb, RTA_DST, dst)) 3006 goto nla_put_failure; 3007 if (src) { 3008 r->rtm_src_len = 32; 3009 if (nla_put_in_addr(skb, RTA_SRC, src)) 3010 goto nla_put_failure; 3011 } 3012 if (rt->dst.dev && 3013 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 3014 goto nla_put_failure; 3015 if (lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 3016 goto nla_put_failure; 3017 #ifdef CONFIG_IP_ROUTE_CLASSID 3018 if (rt->dst.tclassid && 3019 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 3020 goto nla_put_failure; 3021 #endif 3022 if (fl4 && !rt_is_input_route(rt) && 3023 fl4->saddr != src) { 3024 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 3025 goto nla_put_failure; 3026 } 3027 if (rt->rt_uses_gateway) { 3028 if (rt->rt_gw_family == AF_INET && 3029 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 3030 goto nla_put_failure; 3031 } else if (rt->rt_gw_family == AF_INET6) { 3032 int alen = sizeof(struct in6_addr); 3033 struct nlattr *nla; 3034 struct rtvia *via; 3035 3036 nla = nla_reserve(skb, RTA_VIA, alen + 2); 3037 if (!nla) 3038 goto nla_put_failure; 3039 3040 via = nla_data(nla); 3041 via->rtvia_family = AF_INET6; 3042 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 3043 } 3044 } 3045 3046 expires = READ_ONCE(rt->dst.expires); 3047 if (expires) { 3048 unsigned long now = jiffies; 3049 3050 if (time_before(now, expires)) 3051 expires -= now; 3052 else 3053 expires = 0; 3054 } 3055 3056 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 3057 if (rt->rt_pmtu && expires) 3058 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 3059 if (rt->rt_mtu_locked && expires) 3060 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 3061 if (rtnetlink_put_metrics(skb, metrics) < 0) 3062 goto nla_put_failure; 3063 3064 if (fl4) { 3065 if (fl4->flowi4_mark && 3066 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 3067 goto nla_put_failure; 3068 3069 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 3070 nla_put_u32(skb, RTA_UID, 3071 from_kuid_munged(current_user_ns(), 3072 fl4->flowi4_uid))) 3073 goto nla_put_failure; 3074 3075 if (rt_is_input_route(rt)) { 3076 #ifdef CONFIG_IP_MROUTE 3077 if (ipv4_is_multicast(dst) && 3078 !ipv4_is_local_multicast(dst) && 3079 IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) { 3080 int err = ipmr_get_route(net, skb, 3081 fl4->saddr, fl4->daddr, 3082 r, portid); 3083 3084 if (err <= 0) { 3085 if (err == 0) 3086 return 0; 3087 goto nla_put_failure; 3088 } 3089 } else 3090 #endif 3091 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 3092 goto nla_put_failure; 3093 } 3094 } 3095 3096 error = rt->dst.error; 3097 3098 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 3099 goto nla_put_failure; 3100 3101 nlmsg_end(skb, nlh); 3102 return 0; 3103 3104 nla_put_failure: 3105 nlmsg_cancel(skb, nlh); 3106 return -EMSGSIZE; 3107 } 3108 3109 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 3110 struct netlink_callback *cb, u32 table_id, 3111 struct fnhe_hash_bucket *bucket, int genid, 3112 int *fa_index, int fa_start, unsigned int flags) 3113 { 3114 int i; 3115 3116 for (i = 0; i < FNHE_HASH_SIZE; i++) { 3117 struct fib_nh_exception *fnhe; 3118 3119 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 3120 fnhe = rcu_dereference(fnhe->fnhe_next)) { 3121 struct rtable *rt; 3122 int err; 3123 3124 if (*fa_index < fa_start) 3125 goto next; 3126 3127 if (fnhe->fnhe_genid != genid) 3128 goto next; 3129 3130 if (fnhe->fnhe_expires && 3131 time_after(jiffies, fnhe->fnhe_expires)) 3132 goto next; 3133 3134 rt = rcu_dereference(fnhe->fnhe_rth_input); 3135 if (!rt) 3136 rt = rcu_dereference(fnhe->fnhe_rth_output); 3137 if (!rt) 3138 goto next; 3139 3140 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 3141 table_id, 0, NULL, skb, 3142 NETLINK_CB(cb->skb).portid, 3143 cb->nlh->nlmsg_seq, flags); 3144 if (err) 3145 return err; 3146 next: 3147 (*fa_index)++; 3148 } 3149 } 3150 3151 return 0; 3152 } 3153 3154 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 3155 u32 table_id, struct fib_info *fi, 3156 int *fa_index, int fa_start, unsigned int flags) 3157 { 3158 struct net *net = sock_net(cb->skb->sk); 3159 int nhsel, genid = fnhe_genid(net); 3160 3161 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 3162 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 3163 struct fnhe_hash_bucket *bucket; 3164 int err; 3165 3166 if (nhc->nhc_flags & RTNH_F_DEAD) 3167 continue; 3168 3169 rcu_read_lock(); 3170 bucket = rcu_dereference(nhc->nhc_exceptions); 3171 err = 0; 3172 if (bucket) 3173 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 3174 genid, fa_index, fa_start, 3175 flags); 3176 rcu_read_unlock(); 3177 if (err) 3178 return err; 3179 } 3180 3181 return 0; 3182 } 3183 3184 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3185 u8 ip_proto, __be16 sport, 3186 __be16 dport) 3187 { 3188 struct sk_buff *skb; 3189 struct iphdr *iph; 3190 3191 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3192 if (!skb) 3193 return NULL; 3194 3195 /* Reserve room for dummy headers, this skb can pass 3196 * through good chunk of routing engine. 3197 */ 3198 skb_reset_mac_header(skb); 3199 skb_reset_network_header(skb); 3200 skb->protocol = htons(ETH_P_IP); 3201 iph = skb_put(skb, sizeof(struct iphdr)); 3202 iph->protocol = ip_proto; 3203 iph->saddr = src; 3204 iph->daddr = dst; 3205 iph->version = 0x4; 3206 iph->frag_off = 0; 3207 iph->ihl = 0x5; 3208 skb_set_transport_header(skb, skb->len); 3209 3210 switch (iph->protocol) { 3211 case IPPROTO_UDP: { 3212 struct udphdr *udph; 3213 3214 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3215 udph->source = sport; 3216 udph->dest = dport; 3217 udph->len = htons(sizeof(struct udphdr)); 3218 udph->check = 0; 3219 break; 3220 } 3221 case IPPROTO_TCP: { 3222 struct tcphdr *tcph; 3223 3224 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3225 tcph->source = sport; 3226 tcph->dest = dport; 3227 tcph->doff = sizeof(struct tcphdr) / 4; 3228 tcph->rst = 1; 3229 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3230 src, dst, 0); 3231 break; 3232 } 3233 case IPPROTO_ICMP: { 3234 struct icmphdr *icmph; 3235 3236 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3237 icmph->type = ICMP_ECHO; 3238 icmph->code = 0; 3239 } 3240 } 3241 3242 return skb; 3243 } 3244 3245 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3246 const struct nlmsghdr *nlh, 3247 struct nlattr **tb, 3248 struct netlink_ext_ack *extack) 3249 { 3250 struct rtmsg *rtm; 3251 int i, err; 3252 3253 rtm = nlmsg_payload(nlh, sizeof(*rtm)); 3254 if (!rtm) { 3255 NL_SET_ERR_MSG(extack, 3256 "ipv4: Invalid header for route get request"); 3257 return -EINVAL; 3258 } 3259 3260 if (!netlink_strict_get_check(skb)) 3261 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3262 rtm_ipv4_policy, extack); 3263 3264 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3265 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3266 rtm->rtm_table || rtm->rtm_protocol || 3267 rtm->rtm_scope || rtm->rtm_type) { 3268 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3269 return -EINVAL; 3270 } 3271 3272 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3273 RTM_F_LOOKUP_TABLE | 3274 RTM_F_FIB_MATCH)) { 3275 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3276 return -EINVAL; 3277 } 3278 3279 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3280 rtm_ipv4_policy, extack); 3281 if (err) 3282 return err; 3283 3284 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3285 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3286 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3287 return -EINVAL; 3288 } 3289 3290 for (i = 0; i <= RTA_MAX; i++) { 3291 if (!tb[i]) 3292 continue; 3293 3294 switch (i) { 3295 case RTA_IIF: 3296 case RTA_OIF: 3297 case RTA_SRC: 3298 case RTA_DST: 3299 case RTA_IP_PROTO: 3300 case RTA_SPORT: 3301 case RTA_DPORT: 3302 case RTA_MARK: 3303 case RTA_UID: 3304 break; 3305 default: 3306 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3307 return -EINVAL; 3308 } 3309 } 3310 3311 return 0; 3312 } 3313 3314 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3315 struct netlink_ext_ack *extack) 3316 { 3317 struct net *net = sock_net(in_skb->sk); 3318 struct nlattr *tb[RTA_MAX+1]; 3319 u32 table_id = RT_TABLE_MAIN; 3320 __be16 sport = 0, dport = 0; 3321 struct fib_result res = {}; 3322 u8 ip_proto = IPPROTO_UDP; 3323 struct rtable *rt = NULL; 3324 struct sk_buff *skb; 3325 struct rtmsg *rtm; 3326 struct flowi4 fl4 = {}; 3327 __be32 dst = 0; 3328 __be32 src = 0; 3329 dscp_t dscp; 3330 kuid_t uid; 3331 u32 iif; 3332 int err; 3333 int mark; 3334 3335 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3336 if (err < 0) 3337 return err; 3338 3339 rtm = nlmsg_data(nlh); 3340 src = nla_get_in_addr_default(tb[RTA_SRC], 0); 3341 dst = nla_get_in_addr_default(tb[RTA_DST], 0); 3342 iif = nla_get_u32_default(tb[RTA_IIF], 0); 3343 mark = nla_get_u32_default(tb[RTA_MARK], 0); 3344 dscp = inet_dsfield_to_dscp(rtm->rtm_tos); 3345 if (tb[RTA_UID]) 3346 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3347 else 3348 uid = (iif ? INVALID_UID : current_uid()); 3349 3350 if (tb[RTA_IP_PROTO]) { 3351 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3352 &ip_proto, AF_INET, extack); 3353 if (err) 3354 return err; 3355 } 3356 3357 if (tb[RTA_SPORT]) 3358 sport = nla_get_be16(tb[RTA_SPORT]); 3359 3360 if (tb[RTA_DPORT]) 3361 dport = nla_get_be16(tb[RTA_DPORT]); 3362 3363 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3364 if (!skb) 3365 return -ENOBUFS; 3366 3367 fl4.daddr = dst; 3368 fl4.saddr = src; 3369 fl4.flowi4_dscp = dscp; 3370 fl4.flowi4_oif = nla_get_u32_default(tb[RTA_OIF], 0); 3371 fl4.flowi4_mark = mark; 3372 fl4.flowi4_uid = uid; 3373 if (sport) 3374 fl4.fl4_sport = sport; 3375 if (dport) 3376 fl4.fl4_dport = dport; 3377 fl4.flowi4_proto = ip_proto; 3378 3379 rcu_read_lock(); 3380 3381 if (iif) { 3382 struct net_device *dev; 3383 3384 dev = dev_get_by_index_rcu(net, iif); 3385 if (!dev) { 3386 err = -ENODEV; 3387 goto errout_rcu; 3388 } 3389 3390 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3391 skb->dev = dev; 3392 skb->mark = mark; 3393 err = ip_route_input_rcu(skb, dst, src, dscp, dev, 3394 &res) ? -EINVAL : 0; 3395 3396 rt = skb_rtable(skb); 3397 if (err == 0 && rt->dst.error) 3398 err = -rt->dst.error; 3399 } else { 3400 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3401 skb->dev = net->loopback_dev; 3402 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3403 err = 0; 3404 if (IS_ERR(rt)) 3405 err = PTR_ERR(rt); 3406 else 3407 skb_dst_set(skb, &rt->dst); 3408 } 3409 3410 if (err) 3411 goto errout_rcu; 3412 3413 if (rtm->rtm_flags & RTM_F_NOTIFY) 3414 rt->rt_flags |= RTCF_NOTIFY; 3415 3416 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3417 table_id = res.table ? res.table->tb_id : 0; 3418 3419 /* reset skb for netlink reply msg */ 3420 skb_trim(skb, 0); 3421 skb_reset_network_header(skb); 3422 skb_reset_transport_header(skb); 3423 skb_reset_mac_header(skb); 3424 3425 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3426 struct fib_rt_info fri; 3427 3428 if (!res.fi) { 3429 err = fib_props[res.type].error; 3430 if (!err) 3431 err = -EHOSTUNREACH; 3432 goto errout_rcu; 3433 } 3434 fri.fi = res.fi; 3435 fri.tb_id = table_id; 3436 fri.dst = res.prefix; 3437 fri.dst_len = res.prefixlen; 3438 fri.dscp = res.dscp; 3439 fri.type = rt->rt_type; 3440 fri.offload = 0; 3441 fri.trap = 0; 3442 fri.offload_failed = 0; 3443 if (res.fa_head) { 3444 struct fib_alias *fa; 3445 3446 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3447 u8 slen = 32 - fri.dst_len; 3448 3449 if (fa->fa_slen == slen && 3450 fa->tb_id == fri.tb_id && 3451 fa->fa_dscp == fri.dscp && 3452 fa->fa_info == res.fi && 3453 fa->fa_type == fri.type) { 3454 fri.offload = READ_ONCE(fa->offload); 3455 fri.trap = READ_ONCE(fa->trap); 3456 fri.offload_failed = 3457 READ_ONCE(fa->offload_failed); 3458 break; 3459 } 3460 } 3461 } 3462 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3463 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3464 } else { 3465 err = rt_fill_info(net, dst, src, rt, table_id, res.dscp, &fl4, 3466 skb, NETLINK_CB(in_skb).portid, 3467 nlh->nlmsg_seq, 0); 3468 } 3469 if (err < 0) 3470 goto errout_rcu; 3471 3472 rcu_read_unlock(); 3473 3474 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3475 3476 errout_free: 3477 return err; 3478 errout_rcu: 3479 rcu_read_unlock(); 3480 kfree_skb(skb); 3481 goto errout_free; 3482 } 3483 3484 void ip_rt_multicast_event(struct in_device *in_dev) 3485 { 3486 rt_cache_flush(dev_net(in_dev->dev)); 3487 } 3488 3489 #ifdef CONFIG_SYSCTL 3490 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3491 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3492 static int ip_rt_gc_elasticity __read_mostly = 8; 3493 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3494 3495 static int ipv4_sysctl_rtcache_flush(const struct ctl_table *__ctl, int write, 3496 void *buffer, size_t *lenp, loff_t *ppos) 3497 { 3498 struct net *net = (struct net *)__ctl->extra1; 3499 3500 if (write) { 3501 rt_cache_flush(net); 3502 fnhe_genid_bump(net); 3503 return 0; 3504 } 3505 3506 return -EINVAL; 3507 } 3508 3509 static struct ctl_table ipv4_route_table[] = { 3510 { 3511 .procname = "gc_thresh", 3512 .data = &ipv4_dst_ops.gc_thresh, 3513 .maxlen = sizeof(int), 3514 .mode = 0644, 3515 .proc_handler = proc_dointvec, 3516 }, 3517 { 3518 .procname = "max_size", 3519 .data = &ip_rt_max_size, 3520 .maxlen = sizeof(int), 3521 .mode = 0644, 3522 .proc_handler = proc_dointvec, 3523 }, 3524 { 3525 /* Deprecated. Use gc_min_interval_ms */ 3526 3527 .procname = "gc_min_interval", 3528 .data = &ip_rt_gc_min_interval, 3529 .maxlen = sizeof(int), 3530 .mode = 0644, 3531 .proc_handler = proc_dointvec_jiffies, 3532 }, 3533 { 3534 .procname = "gc_min_interval_ms", 3535 .data = &ip_rt_gc_min_interval, 3536 .maxlen = sizeof(int), 3537 .mode = 0644, 3538 .proc_handler = proc_dointvec_ms_jiffies, 3539 }, 3540 { 3541 .procname = "gc_timeout", 3542 .data = &ip_rt_gc_timeout, 3543 .maxlen = sizeof(int), 3544 .mode = 0644, 3545 .proc_handler = proc_dointvec_jiffies, 3546 }, 3547 { 3548 .procname = "gc_interval", 3549 .data = &ip_rt_gc_interval, 3550 .maxlen = sizeof(int), 3551 .mode = 0644, 3552 .proc_handler = proc_dointvec_jiffies, 3553 }, 3554 { 3555 .procname = "redirect_load", 3556 .data = &ip_rt_redirect_load, 3557 .maxlen = sizeof(int), 3558 .mode = 0644, 3559 .proc_handler = proc_dointvec, 3560 }, 3561 { 3562 .procname = "redirect_number", 3563 .data = &ip_rt_redirect_number, 3564 .maxlen = sizeof(int), 3565 .mode = 0644, 3566 .proc_handler = proc_dointvec, 3567 }, 3568 { 3569 .procname = "redirect_silence", 3570 .data = &ip_rt_redirect_silence, 3571 .maxlen = sizeof(int), 3572 .mode = 0644, 3573 .proc_handler = proc_dointvec, 3574 }, 3575 { 3576 .procname = "error_cost", 3577 .data = &ip_rt_error_cost, 3578 .maxlen = sizeof(int), 3579 .mode = 0644, 3580 .proc_handler = proc_dointvec, 3581 }, 3582 { 3583 .procname = "error_burst", 3584 .data = &ip_rt_error_burst, 3585 .maxlen = sizeof(int), 3586 .mode = 0644, 3587 .proc_handler = proc_dointvec, 3588 }, 3589 { 3590 .procname = "gc_elasticity", 3591 .data = &ip_rt_gc_elasticity, 3592 .maxlen = sizeof(int), 3593 .mode = 0644, 3594 .proc_handler = proc_dointvec, 3595 }, 3596 }; 3597 3598 static const char ipv4_route_flush_procname[] = "flush"; 3599 3600 static struct ctl_table ipv4_route_netns_table[] = { 3601 { 3602 .procname = ipv4_route_flush_procname, 3603 .maxlen = sizeof(int), 3604 .mode = 0200, 3605 .proc_handler = ipv4_sysctl_rtcache_flush, 3606 }, 3607 { 3608 .procname = "min_pmtu", 3609 .data = &init_net.ipv4.ip_rt_min_pmtu, 3610 .maxlen = sizeof(int), 3611 .mode = 0644, 3612 .proc_handler = proc_dointvec_minmax, 3613 .extra1 = &ip_min_valid_pmtu, 3614 }, 3615 { 3616 .procname = "mtu_expires", 3617 .data = &init_net.ipv4.ip_rt_mtu_expires, 3618 .maxlen = sizeof(int), 3619 .mode = 0644, 3620 .proc_handler = proc_dointvec_jiffies, 3621 }, 3622 { 3623 .procname = "min_adv_mss", 3624 .data = &init_net.ipv4.ip_rt_min_advmss, 3625 .maxlen = sizeof(int), 3626 .mode = 0644, 3627 .proc_handler = proc_dointvec, 3628 }, 3629 }; 3630 3631 static __net_init int sysctl_route_net_init(struct net *net) 3632 { 3633 struct ctl_table *tbl; 3634 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table); 3635 3636 tbl = ipv4_route_netns_table; 3637 if (!net_eq(net, &init_net)) { 3638 int i; 3639 3640 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL); 3641 if (!tbl) 3642 goto err_dup; 3643 3644 /* Don't export non-whitelisted sysctls to unprivileged users */ 3645 if (net->user_ns != &init_user_ns) { 3646 if (tbl[0].procname != ipv4_route_flush_procname) 3647 table_size = 0; 3648 } 3649 3650 /* Update the variables to point into the current struct net 3651 * except for the first element flush 3652 */ 3653 for (i = 1; i < table_size; i++) 3654 tbl[i].data += (void *)net - (void *)&init_net; 3655 } 3656 tbl[0].extra1 = net; 3657 3658 net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route", 3659 tbl, table_size); 3660 if (!net->ipv4.route_hdr) 3661 goto err_reg; 3662 return 0; 3663 3664 err_reg: 3665 if (tbl != ipv4_route_netns_table) 3666 kfree(tbl); 3667 err_dup: 3668 return -ENOMEM; 3669 } 3670 3671 static __net_exit void sysctl_route_net_exit(struct net *net) 3672 { 3673 const struct ctl_table *tbl; 3674 3675 tbl = net->ipv4.route_hdr->ctl_table_arg; 3676 unregister_net_sysctl_table(net->ipv4.route_hdr); 3677 BUG_ON(tbl == ipv4_route_netns_table); 3678 kfree(tbl); 3679 } 3680 3681 static __net_initdata struct pernet_operations sysctl_route_ops = { 3682 .init = sysctl_route_net_init, 3683 .exit = sysctl_route_net_exit, 3684 }; 3685 #endif 3686 3687 static __net_init int netns_ip_rt_init(struct net *net) 3688 { 3689 /* Set default value for namespaceified sysctls */ 3690 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU; 3691 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES; 3692 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS; 3693 return 0; 3694 } 3695 3696 static struct pernet_operations __net_initdata ip_rt_ops = { 3697 .init = netns_ip_rt_init, 3698 }; 3699 3700 static __net_init int rt_genid_init(struct net *net) 3701 { 3702 atomic_set(&net->ipv4.rt_genid, 0); 3703 atomic_set(&net->fnhe_genid, 0); 3704 atomic_set(&net->ipv4.dev_addr_genid, get_random_u32()); 3705 return 0; 3706 } 3707 3708 static __net_initdata struct pernet_operations rt_genid_ops = { 3709 .init = rt_genid_init, 3710 }; 3711 3712 static int __net_init ipv4_inetpeer_init(struct net *net) 3713 { 3714 struct inet_peer_base *bp = kmalloc_obj(*bp); 3715 3716 if (!bp) 3717 return -ENOMEM; 3718 inet_peer_base_init(bp); 3719 net->ipv4.peers = bp; 3720 return 0; 3721 } 3722 3723 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3724 { 3725 struct inet_peer_base *bp = net->ipv4.peers; 3726 3727 net->ipv4.peers = NULL; 3728 inetpeer_invalidate_tree(bp); 3729 kfree(bp); 3730 } 3731 3732 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3733 .init = ipv4_inetpeer_init, 3734 .exit = ipv4_inetpeer_exit, 3735 }; 3736 3737 #ifdef CONFIG_IP_ROUTE_CLASSID 3738 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3739 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3740 3741 static const struct rtnl_msg_handler ip_rt_rtnl_msg_handlers[] __initconst = { 3742 {.protocol = PF_INET, .msgtype = RTM_GETROUTE, 3743 .doit = inet_rtm_getroute, .flags = RTNL_FLAG_DOIT_UNLOCKED}, 3744 }; 3745 3746 int __init ip_rt_init(void) 3747 { 3748 void *idents_hash; 3749 int cpu; 3750 3751 /* For modern hosts, this will use 2 MB of memory */ 3752 idents_hash = alloc_large_system_hash("IP idents", 3753 sizeof(*ip_idents) + sizeof(*ip_tstamps), 3754 0, 3755 16, /* one bucket per 64 KB */ 3756 HASH_ZERO, 3757 NULL, 3758 &ip_idents_mask, 3759 2048, 3760 256*1024); 3761 3762 ip_idents = idents_hash; 3763 3764 get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents)); 3765 3766 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents); 3767 3768 for_each_possible_cpu(cpu) { 3769 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3770 3771 INIT_LIST_HEAD(&ul->head); 3772 spin_lock_init(&ul->lock); 3773 } 3774 #ifdef CONFIG_IP_ROUTE_CLASSID 3775 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3776 if (!ip_rt_acct) 3777 panic("IP: failed to allocate ip_rt_acct\n"); 3778 #endif 3779 3780 ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable, 3781 SLAB_HWCACHE_ALIGN | SLAB_PANIC); 3782 3783 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3784 3785 if (dst_entries_init(&ipv4_dst_ops) < 0) 3786 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3787 3788 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3789 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3790 3791 ipv4_dst_ops.gc_thresh = ~0; 3792 ip_rt_max_size = INT_MAX; 3793 3794 devinet_init(); 3795 ip_fib_init(); 3796 3797 if (ip_rt_proc_init()) 3798 pr_err("Unable to create route proc files\n"); 3799 #ifdef CONFIG_XFRM 3800 xfrm_init(); 3801 xfrm4_init(); 3802 #endif 3803 rtnl_register_many(ip_rt_rtnl_msg_handlers); 3804 3805 #ifdef CONFIG_SYSCTL 3806 register_pernet_subsys(&sysctl_route_ops); 3807 #endif 3808 register_pernet_subsys(&ip_rt_ops); 3809 register_pernet_subsys(&rt_genid_ops); 3810 register_pernet_subsys(&ipv4_inetpeer_ops); 3811 return 0; 3812 } 3813 3814 #ifdef CONFIG_SYSCTL 3815 /* 3816 * We really need to sanitize the damn ipv4 init order, then all 3817 * this nonsense will go away. 3818 */ 3819 void __init ip_static_sysctl_init(void) 3820 { 3821 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3822 } 3823 #endif 3824