1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * ROUTE - implementation of the IP router. 8 * 9 * Authors: Ross Biro 10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * Alan Cox, <gw4pts@gw4pts.ampr.org> 12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 14 * 15 * Fixes: 16 * Alan Cox : Verify area fixes. 17 * Alan Cox : cli() protects routing changes 18 * Rui Oliveira : ICMP routing table updates 19 * (rco@di.uminho.pt) Routing table insertion and update 20 * Linus Torvalds : Rewrote bits to be sensible 21 * Alan Cox : Added BSD route gw semantics 22 * Alan Cox : Super /proc >4K 23 * Alan Cox : MTU in route table 24 * Alan Cox : MSS actually. Also added the window 25 * clamper. 26 * Sam Lantinga : Fixed route matching in rt_del() 27 * Alan Cox : Routing cache support. 28 * Alan Cox : Removed compatibility cruft. 29 * Alan Cox : RTF_REJECT support. 30 * Alan Cox : TCP irtt support. 31 * Jonathan Naylor : Added Metric support. 32 * Miquel van Smoorenburg : BSD API fixes. 33 * Miquel van Smoorenburg : Metrics. 34 * Alan Cox : Use __u32 properly 35 * Alan Cox : Aligned routing errors more closely with BSD 36 * our system is still very different. 37 * Alan Cox : Faster /proc handling 38 * Alexey Kuznetsov : Massive rework to support tree based routing, 39 * routing caches and better behaviour. 40 * 41 * Olaf Erb : irtt wasn't being copied right. 42 * Bjorn Ekwall : Kerneld route support. 43 * Alan Cox : Multicast fixed (I hope) 44 * Pavel Krauz : Limited broadcast fixed 45 * Mike McLagan : Routing by source 46 * Alexey Kuznetsov : End of old history. Split to fib.c and 47 * route.c and rewritten from scratch. 48 * Andi Kleen : Load-limit warning messages. 49 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 53 * Marc Boucher : routing by fwmark 54 * Robert Olsson : Added rt_cache statistics 55 * Arnaldo C. Melo : Convert proc stuff to seq_file 56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 58 * Ilia Sotnikov : Removed TOS from hash calculations 59 */ 60 61 #define pr_fmt(fmt) "IPv4: " fmt 62 63 #include <linux/module.h> 64 #include <linux/uaccess.h> 65 #include <linux/bitops.h> 66 #include <linux/types.h> 67 #include <linux/kernel.h> 68 #include <linux/mm.h> 69 #include <linux/memblock.h> 70 #include <linux/string.h> 71 #include <linux/socket.h> 72 #include <linux/sockios.h> 73 #include <linux/errno.h> 74 #include <linux/in.h> 75 #include <linux/inet.h> 76 #include <linux/netdevice.h> 77 #include <linux/proc_fs.h> 78 #include <linux/init.h> 79 #include <linux/skbuff.h> 80 #include <linux/inetdevice.h> 81 #include <linux/igmp.h> 82 #include <linux/pkt_sched.h> 83 #include <linux/mroute.h> 84 #include <linux/netfilter_ipv4.h> 85 #include <linux/random.h> 86 #include <linux/rcupdate.h> 87 #include <linux/times.h> 88 #include <linux/slab.h> 89 #include <linux/jhash.h> 90 #include <net/dst.h> 91 #include <net/dst_metadata.h> 92 #include <net/net_namespace.h> 93 #include <net/protocol.h> 94 #include <net/ip.h> 95 #include <net/route.h> 96 #include <net/inetpeer.h> 97 #include <net/sock.h> 98 #include <net/ip_fib.h> 99 #include <net/nexthop.h> 100 #include <net/arp.h> 101 #include <net/tcp.h> 102 #include <net/icmp.h> 103 #include <net/xfrm.h> 104 #include <net/lwtunnel.h> 105 #include <net/netevent.h> 106 #include <net/rtnetlink.h> 107 #ifdef CONFIG_SYSCTL 108 #include <linux/sysctl.h> 109 #endif 110 #include <net/secure_seq.h> 111 #include <net/ip_tunnels.h> 112 #include <net/l3mdev.h> 113 114 #include "fib_lookup.h" 115 116 #define RT_FL_TOS(oldflp4) \ 117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 118 119 #define RT_GC_TIMEOUT (300*HZ) 120 121 static int ip_rt_max_size; 122 static int ip_rt_redirect_number __read_mostly = 9; 123 static int ip_rt_redirect_load __read_mostly = HZ / 50; 124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 125 static int ip_rt_error_cost __read_mostly = HZ; 126 static int ip_rt_error_burst __read_mostly = 5 * HZ; 127 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 128 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 129 static int ip_rt_min_advmss __read_mostly = 256; 130 131 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 132 133 /* 134 * Interface to generic destination cache. 135 */ 136 137 INDIRECT_CALLABLE_SCOPE 138 struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 139 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 140 INDIRECT_CALLABLE_SCOPE 141 unsigned int ipv4_mtu(const struct dst_entry *dst); 142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 143 static void ipv4_link_failure(struct sk_buff *skb); 144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 145 struct sk_buff *skb, u32 mtu, 146 bool confirm_neigh); 147 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 148 struct sk_buff *skb); 149 static void ipv4_dst_destroy(struct dst_entry *dst); 150 151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 152 { 153 WARN_ON(1); 154 return NULL; 155 } 156 157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 158 struct sk_buff *skb, 159 const void *daddr); 160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 161 162 static struct dst_ops ipv4_dst_ops = { 163 .family = AF_INET, 164 .check = ipv4_dst_check, 165 .default_advmss = ipv4_default_advmss, 166 .mtu = ipv4_mtu, 167 .cow_metrics = ipv4_cow_metrics, 168 .destroy = ipv4_dst_destroy, 169 .negative_advice = ipv4_negative_advice, 170 .link_failure = ipv4_link_failure, 171 .update_pmtu = ip_rt_update_pmtu, 172 .redirect = ip_do_redirect, 173 .local_out = __ip_local_out, 174 .neigh_lookup = ipv4_neigh_lookup, 175 .confirm_neigh = ipv4_confirm_neigh, 176 }; 177 178 #define ECN_OR_COST(class) TC_PRIO_##class 179 180 const __u8 ip_tos2prio[16] = { 181 TC_PRIO_BESTEFFORT, 182 ECN_OR_COST(BESTEFFORT), 183 TC_PRIO_BESTEFFORT, 184 ECN_OR_COST(BESTEFFORT), 185 TC_PRIO_BULK, 186 ECN_OR_COST(BULK), 187 TC_PRIO_BULK, 188 ECN_OR_COST(BULK), 189 TC_PRIO_INTERACTIVE, 190 ECN_OR_COST(INTERACTIVE), 191 TC_PRIO_INTERACTIVE, 192 ECN_OR_COST(INTERACTIVE), 193 TC_PRIO_INTERACTIVE_BULK, 194 ECN_OR_COST(INTERACTIVE_BULK), 195 TC_PRIO_INTERACTIVE_BULK, 196 ECN_OR_COST(INTERACTIVE_BULK) 197 }; 198 EXPORT_SYMBOL(ip_tos2prio); 199 200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 202 203 #ifdef CONFIG_PROC_FS 204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 205 { 206 if (*pos) 207 return NULL; 208 return SEQ_START_TOKEN; 209 } 210 211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 212 { 213 ++*pos; 214 return NULL; 215 } 216 217 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 218 { 219 } 220 221 static int rt_cache_seq_show(struct seq_file *seq, void *v) 222 { 223 if (v == SEQ_START_TOKEN) 224 seq_printf(seq, "%-127s\n", 225 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 226 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 227 "HHUptod\tSpecDst"); 228 return 0; 229 } 230 231 static const struct seq_operations rt_cache_seq_ops = { 232 .start = rt_cache_seq_start, 233 .next = rt_cache_seq_next, 234 .stop = rt_cache_seq_stop, 235 .show = rt_cache_seq_show, 236 }; 237 238 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 239 { 240 int cpu; 241 242 if (*pos == 0) 243 return SEQ_START_TOKEN; 244 245 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 246 if (!cpu_possible(cpu)) 247 continue; 248 *pos = cpu+1; 249 return &per_cpu(rt_cache_stat, cpu); 250 } 251 return NULL; 252 } 253 254 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 255 { 256 int cpu; 257 258 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 259 if (!cpu_possible(cpu)) 260 continue; 261 *pos = cpu+1; 262 return &per_cpu(rt_cache_stat, cpu); 263 } 264 (*pos)++; 265 return NULL; 266 267 } 268 269 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 270 { 271 272 } 273 274 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 275 { 276 struct rt_cache_stat *st = v; 277 278 if (v == SEQ_START_TOKEN) { 279 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"); 280 return 0; 281 } 282 283 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 284 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 285 dst_entries_get_slow(&ipv4_dst_ops), 286 0, /* st->in_hit */ 287 st->in_slow_tot, 288 st->in_slow_mc, 289 st->in_no_route, 290 st->in_brd, 291 st->in_martian_dst, 292 st->in_martian_src, 293 294 0, /* st->out_hit */ 295 st->out_slow_tot, 296 st->out_slow_mc, 297 298 0, /* st->gc_total */ 299 0, /* st->gc_ignored */ 300 0, /* st->gc_goal_miss */ 301 0, /* st->gc_dst_overflow */ 302 0, /* st->in_hlist_search */ 303 0 /* st->out_hlist_search */ 304 ); 305 return 0; 306 } 307 308 static const struct seq_operations rt_cpu_seq_ops = { 309 .start = rt_cpu_seq_start, 310 .next = rt_cpu_seq_next, 311 .stop = rt_cpu_seq_stop, 312 .show = rt_cpu_seq_show, 313 }; 314 315 #ifdef CONFIG_IP_ROUTE_CLASSID 316 static int rt_acct_proc_show(struct seq_file *m, void *v) 317 { 318 struct ip_rt_acct *dst, *src; 319 unsigned int i, j; 320 321 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 322 if (!dst) 323 return -ENOMEM; 324 325 for_each_possible_cpu(i) { 326 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 327 for (j = 0; j < 256; j++) { 328 dst[j].o_bytes += src[j].o_bytes; 329 dst[j].o_packets += src[j].o_packets; 330 dst[j].i_bytes += src[j].i_bytes; 331 dst[j].i_packets += src[j].i_packets; 332 } 333 } 334 335 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 336 kfree(dst); 337 return 0; 338 } 339 #endif 340 341 static int __net_init ip_rt_do_proc_init(struct net *net) 342 { 343 struct proc_dir_entry *pde; 344 345 pde = proc_create_seq("rt_cache", 0444, net->proc_net, 346 &rt_cache_seq_ops); 347 if (!pde) 348 goto err1; 349 350 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat, 351 &rt_cpu_seq_ops); 352 if (!pde) 353 goto err2; 354 355 #ifdef CONFIG_IP_ROUTE_CLASSID 356 pde = proc_create_single("rt_acct", 0, net->proc_net, 357 rt_acct_proc_show); 358 if (!pde) 359 goto err3; 360 #endif 361 return 0; 362 363 #ifdef CONFIG_IP_ROUTE_CLASSID 364 err3: 365 remove_proc_entry("rt_cache", net->proc_net_stat); 366 #endif 367 err2: 368 remove_proc_entry("rt_cache", net->proc_net); 369 err1: 370 return -ENOMEM; 371 } 372 373 static void __net_exit ip_rt_do_proc_exit(struct net *net) 374 { 375 remove_proc_entry("rt_cache", net->proc_net_stat); 376 remove_proc_entry("rt_cache", net->proc_net); 377 #ifdef CONFIG_IP_ROUTE_CLASSID 378 remove_proc_entry("rt_acct", net->proc_net); 379 #endif 380 } 381 382 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 383 .init = ip_rt_do_proc_init, 384 .exit = ip_rt_do_proc_exit, 385 }; 386 387 static int __init ip_rt_proc_init(void) 388 { 389 return register_pernet_subsys(&ip_rt_proc_ops); 390 } 391 392 #else 393 static inline int ip_rt_proc_init(void) 394 { 395 return 0; 396 } 397 #endif /* CONFIG_PROC_FS */ 398 399 static inline bool rt_is_expired(const struct rtable *rth) 400 { 401 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 402 } 403 404 void rt_cache_flush(struct net *net) 405 { 406 rt_genid_bump_ipv4(net); 407 } 408 409 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 410 struct sk_buff *skb, 411 const void *daddr) 412 { 413 const struct rtable *rt = container_of(dst, struct rtable, dst); 414 struct net_device *dev = dst->dev; 415 struct neighbour *n; 416 417 rcu_read_lock_bh(); 418 419 if (likely(rt->rt_gw_family == AF_INET)) { 420 n = ip_neigh_gw4(dev, rt->rt_gw4); 421 } else if (rt->rt_gw_family == AF_INET6) { 422 n = ip_neigh_gw6(dev, &rt->rt_gw6); 423 } else { 424 __be32 pkey; 425 426 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 427 n = ip_neigh_gw4(dev, pkey); 428 } 429 430 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 431 n = NULL; 432 433 rcu_read_unlock_bh(); 434 435 return n; 436 } 437 438 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 439 { 440 const struct rtable *rt = container_of(dst, struct rtable, dst); 441 struct net_device *dev = dst->dev; 442 const __be32 *pkey = daddr; 443 444 if (rt->rt_gw_family == AF_INET) { 445 pkey = (const __be32 *)&rt->rt_gw4; 446 } else if (rt->rt_gw_family == AF_INET6) { 447 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 448 } else if (!daddr || 449 (rt->rt_flags & 450 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 451 return; 452 } 453 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 454 } 455 456 /* Hash tables of size 2048..262144 depending on RAM size. 457 * Each bucket uses 8 bytes. 458 */ 459 static u32 ip_idents_mask __read_mostly; 460 static atomic_t *ip_idents __read_mostly; 461 static u32 *ip_tstamps __read_mostly; 462 463 /* In order to protect privacy, we add a perturbation to identifiers 464 * if one generator is seldom used. This makes hard for an attacker 465 * to infer how many packets were sent between two points in time. 466 */ 467 u32 ip_idents_reserve(u32 hash, int segs) 468 { 469 u32 bucket, old, now = (u32)jiffies; 470 atomic_t *p_id; 471 u32 *p_tstamp; 472 u32 delta = 0; 473 474 bucket = hash & ip_idents_mask; 475 p_tstamp = ip_tstamps + bucket; 476 p_id = ip_idents + bucket; 477 old = READ_ONCE(*p_tstamp); 478 479 if (old != now && cmpxchg(p_tstamp, old, now) == old) 480 delta = prandom_u32_max(now - old); 481 482 /* If UBSAN reports an error there, please make sure your compiler 483 * supports -fno-strict-overflow before reporting it that was a bug 484 * in UBSAN, and it has been fixed in GCC-8. 485 */ 486 return atomic_add_return(segs + delta, p_id) - segs; 487 } 488 EXPORT_SYMBOL(ip_idents_reserve); 489 490 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 491 { 492 u32 hash, id; 493 494 /* Note the following code is not safe, but this is okay. */ 495 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 496 get_random_bytes(&net->ipv4.ip_id_key, 497 sizeof(net->ipv4.ip_id_key)); 498 499 hash = siphash_3u32((__force u32)iph->daddr, 500 (__force u32)iph->saddr, 501 iph->protocol, 502 &net->ipv4.ip_id_key); 503 id = ip_idents_reserve(hash, segs); 504 iph->id = htons(id); 505 } 506 EXPORT_SYMBOL(__ip_select_ident); 507 508 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 509 const struct sock *sk, 510 const struct iphdr *iph, 511 int oif, u8 tos, 512 u8 prot, u32 mark, int flow_flags) 513 { 514 if (sk) { 515 const struct inet_sock *inet = inet_sk(sk); 516 517 oif = sk->sk_bound_dev_if; 518 mark = sk->sk_mark; 519 tos = RT_CONN_FLAGS(sk); 520 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 521 } 522 flowi4_init_output(fl4, oif, mark, tos, 523 RT_SCOPE_UNIVERSE, prot, 524 flow_flags, 525 iph->daddr, iph->saddr, 0, 0, 526 sock_net_uid(net, sk)); 527 } 528 529 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 530 const struct sock *sk) 531 { 532 const struct net *net = dev_net(skb->dev); 533 const struct iphdr *iph = ip_hdr(skb); 534 int oif = skb->dev->ifindex; 535 u8 tos = RT_TOS(iph->tos); 536 u8 prot = iph->protocol; 537 u32 mark = skb->mark; 538 539 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 540 } 541 542 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 543 { 544 const struct inet_sock *inet = inet_sk(sk); 545 const struct ip_options_rcu *inet_opt; 546 __be32 daddr = inet->inet_daddr; 547 548 rcu_read_lock(); 549 inet_opt = rcu_dereference(inet->inet_opt); 550 if (inet_opt && inet_opt->opt.srr) 551 daddr = inet_opt->opt.faddr; 552 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 553 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 554 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 555 inet_sk_flowi_flags(sk), 556 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 557 rcu_read_unlock(); 558 } 559 560 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 561 const struct sk_buff *skb) 562 { 563 if (skb) 564 build_skb_flow_key(fl4, skb, sk); 565 else 566 build_sk_flow_key(fl4, sk); 567 } 568 569 static DEFINE_SPINLOCK(fnhe_lock); 570 571 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 572 { 573 struct rtable *rt; 574 575 rt = rcu_dereference(fnhe->fnhe_rth_input); 576 if (rt) { 577 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 578 dst_dev_put(&rt->dst); 579 dst_release(&rt->dst); 580 } 581 rt = rcu_dereference(fnhe->fnhe_rth_output); 582 if (rt) { 583 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 584 dst_dev_put(&rt->dst); 585 dst_release(&rt->dst); 586 } 587 } 588 589 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 590 { 591 struct fib_nh_exception *fnhe, *oldest; 592 593 oldest = rcu_dereference(hash->chain); 594 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 595 fnhe = rcu_dereference(fnhe->fnhe_next)) { 596 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 597 oldest = fnhe; 598 } 599 fnhe_flush_routes(oldest); 600 return oldest; 601 } 602 603 static inline u32 fnhe_hashfun(__be32 daddr) 604 { 605 static u32 fnhe_hashrnd __read_mostly; 606 u32 hval; 607 608 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 609 hval = jhash_1word((__force u32)daddr, fnhe_hashrnd); 610 return hash_32(hval, FNHE_HASH_SHIFT); 611 } 612 613 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 614 { 615 rt->rt_pmtu = fnhe->fnhe_pmtu; 616 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 617 rt->dst.expires = fnhe->fnhe_expires; 618 619 if (fnhe->fnhe_gw) { 620 rt->rt_flags |= RTCF_REDIRECTED; 621 rt->rt_uses_gateway = 1; 622 rt->rt_gw_family = AF_INET; 623 rt->rt_gw4 = fnhe->fnhe_gw; 624 } 625 } 626 627 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 628 __be32 gw, u32 pmtu, bool lock, 629 unsigned long expires) 630 { 631 struct fnhe_hash_bucket *hash; 632 struct fib_nh_exception *fnhe; 633 struct rtable *rt; 634 u32 genid, hval; 635 unsigned int i; 636 int depth; 637 638 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 639 hval = fnhe_hashfun(daddr); 640 641 spin_lock_bh(&fnhe_lock); 642 643 hash = rcu_dereference(nhc->nhc_exceptions); 644 if (!hash) { 645 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 646 if (!hash) 647 goto out_unlock; 648 rcu_assign_pointer(nhc->nhc_exceptions, hash); 649 } 650 651 hash += hval; 652 653 depth = 0; 654 for (fnhe = rcu_dereference(hash->chain); fnhe; 655 fnhe = rcu_dereference(fnhe->fnhe_next)) { 656 if (fnhe->fnhe_daddr == daddr) 657 break; 658 depth++; 659 } 660 661 if (fnhe) { 662 if (fnhe->fnhe_genid != genid) 663 fnhe->fnhe_genid = genid; 664 if (gw) 665 fnhe->fnhe_gw = gw; 666 if (pmtu) { 667 fnhe->fnhe_pmtu = pmtu; 668 fnhe->fnhe_mtu_locked = lock; 669 } 670 fnhe->fnhe_expires = max(1UL, expires); 671 /* Update all cached dsts too */ 672 rt = rcu_dereference(fnhe->fnhe_rth_input); 673 if (rt) 674 fill_route_from_fnhe(rt, fnhe); 675 rt = rcu_dereference(fnhe->fnhe_rth_output); 676 if (rt) 677 fill_route_from_fnhe(rt, fnhe); 678 } else { 679 if (depth > FNHE_RECLAIM_DEPTH) 680 fnhe = fnhe_oldest(hash); 681 else { 682 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 683 if (!fnhe) 684 goto out_unlock; 685 686 fnhe->fnhe_next = hash->chain; 687 rcu_assign_pointer(hash->chain, fnhe); 688 } 689 fnhe->fnhe_genid = genid; 690 fnhe->fnhe_daddr = daddr; 691 fnhe->fnhe_gw = gw; 692 fnhe->fnhe_pmtu = pmtu; 693 fnhe->fnhe_mtu_locked = lock; 694 fnhe->fnhe_expires = max(1UL, expires); 695 696 /* Exception created; mark the cached routes for the nexthop 697 * stale, so anyone caching it rechecks if this exception 698 * applies to them. 699 */ 700 rt = rcu_dereference(nhc->nhc_rth_input); 701 if (rt) 702 rt->dst.obsolete = DST_OBSOLETE_KILL; 703 704 for_each_possible_cpu(i) { 705 struct rtable __rcu **prt; 706 707 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 708 rt = rcu_dereference(*prt); 709 if (rt) 710 rt->dst.obsolete = DST_OBSOLETE_KILL; 711 } 712 } 713 714 fnhe->fnhe_stamp = jiffies; 715 716 out_unlock: 717 spin_unlock_bh(&fnhe_lock); 718 } 719 720 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 721 bool kill_route) 722 { 723 __be32 new_gw = icmp_hdr(skb)->un.gateway; 724 __be32 old_gw = ip_hdr(skb)->saddr; 725 struct net_device *dev = skb->dev; 726 struct in_device *in_dev; 727 struct fib_result res; 728 struct neighbour *n; 729 struct net *net; 730 731 switch (icmp_hdr(skb)->code & 7) { 732 case ICMP_REDIR_NET: 733 case ICMP_REDIR_NETTOS: 734 case ICMP_REDIR_HOST: 735 case ICMP_REDIR_HOSTTOS: 736 break; 737 738 default: 739 return; 740 } 741 742 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 743 return; 744 745 in_dev = __in_dev_get_rcu(dev); 746 if (!in_dev) 747 return; 748 749 net = dev_net(dev); 750 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 751 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 752 ipv4_is_zeronet(new_gw)) 753 goto reject_redirect; 754 755 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 756 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 757 goto reject_redirect; 758 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 759 goto reject_redirect; 760 } else { 761 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 762 goto reject_redirect; 763 } 764 765 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 766 if (!n) 767 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 768 if (!IS_ERR(n)) { 769 if (!(n->nud_state & NUD_VALID)) { 770 neigh_event_send(n, NULL); 771 } else { 772 if (fib_lookup(net, fl4, &res, 0) == 0) { 773 struct fib_nh_common *nhc; 774 775 fib_select_path(net, &res, fl4, skb); 776 nhc = FIB_RES_NHC(res); 777 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 778 0, false, 779 jiffies + ip_rt_gc_timeout); 780 } 781 if (kill_route) 782 rt->dst.obsolete = DST_OBSOLETE_KILL; 783 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 784 } 785 neigh_release(n); 786 } 787 return; 788 789 reject_redirect: 790 #ifdef CONFIG_IP_ROUTE_VERBOSE 791 if (IN_DEV_LOG_MARTIANS(in_dev)) { 792 const struct iphdr *iph = (const struct iphdr *) skb->data; 793 __be32 daddr = iph->daddr; 794 __be32 saddr = iph->saddr; 795 796 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 797 " Advised path = %pI4 -> %pI4\n", 798 &old_gw, dev->name, &new_gw, 799 &saddr, &daddr); 800 } 801 #endif 802 ; 803 } 804 805 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 806 { 807 struct rtable *rt; 808 struct flowi4 fl4; 809 const struct iphdr *iph = (const struct iphdr *) skb->data; 810 struct net *net = dev_net(skb->dev); 811 int oif = skb->dev->ifindex; 812 u8 tos = RT_TOS(iph->tos); 813 u8 prot = iph->protocol; 814 u32 mark = skb->mark; 815 816 rt = (struct rtable *) dst; 817 818 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 819 __ip_do_redirect(rt, skb, &fl4, true); 820 } 821 822 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 823 { 824 struct rtable *rt = (struct rtable *)dst; 825 struct dst_entry *ret = dst; 826 827 if (rt) { 828 if (dst->obsolete > 0) { 829 ip_rt_put(rt); 830 ret = NULL; 831 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 832 rt->dst.expires) { 833 ip_rt_put(rt); 834 ret = NULL; 835 } 836 } 837 return ret; 838 } 839 840 /* 841 * Algorithm: 842 * 1. The first ip_rt_redirect_number redirects are sent 843 * with exponential backoff, then we stop sending them at all, 844 * assuming that the host ignores our redirects. 845 * 2. If we did not see packets requiring redirects 846 * during ip_rt_redirect_silence, we assume that the host 847 * forgot redirected route and start to send redirects again. 848 * 849 * This algorithm is much cheaper and more intelligent than dumb load limiting 850 * in icmp.c. 851 * 852 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 853 * and "frag. need" (breaks PMTU discovery) in icmp.c. 854 */ 855 856 void ip_rt_send_redirect(struct sk_buff *skb) 857 { 858 struct rtable *rt = skb_rtable(skb); 859 struct in_device *in_dev; 860 struct inet_peer *peer; 861 struct net *net; 862 int log_martians; 863 int vif; 864 865 rcu_read_lock(); 866 in_dev = __in_dev_get_rcu(rt->dst.dev); 867 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 868 rcu_read_unlock(); 869 return; 870 } 871 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 872 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 873 rcu_read_unlock(); 874 875 net = dev_net(rt->dst.dev); 876 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 877 if (!peer) { 878 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 879 rt_nexthop(rt, ip_hdr(skb)->daddr)); 880 return; 881 } 882 883 /* No redirected packets during ip_rt_redirect_silence; 884 * reset the algorithm. 885 */ 886 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 887 peer->rate_tokens = 0; 888 peer->n_redirects = 0; 889 } 890 891 /* Too many ignored redirects; do not send anything 892 * set dst.rate_last to the last seen redirected packet. 893 */ 894 if (peer->n_redirects >= ip_rt_redirect_number) { 895 peer->rate_last = jiffies; 896 goto out_put_peer; 897 } 898 899 /* Check for load limit; set rate_last to the latest sent 900 * redirect. 901 */ 902 if (peer->n_redirects == 0 || 903 time_after(jiffies, 904 (peer->rate_last + 905 (ip_rt_redirect_load << peer->n_redirects)))) { 906 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 907 908 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 909 peer->rate_last = jiffies; 910 ++peer->n_redirects; 911 #ifdef CONFIG_IP_ROUTE_VERBOSE 912 if (log_martians && 913 peer->n_redirects == ip_rt_redirect_number) 914 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 915 &ip_hdr(skb)->saddr, inet_iif(skb), 916 &ip_hdr(skb)->daddr, &gw); 917 #endif 918 } 919 out_put_peer: 920 inet_putpeer(peer); 921 } 922 923 static int ip_error(struct sk_buff *skb) 924 { 925 struct rtable *rt = skb_rtable(skb); 926 struct net_device *dev = skb->dev; 927 struct in_device *in_dev; 928 struct inet_peer *peer; 929 unsigned long now; 930 struct net *net; 931 bool send; 932 int code; 933 934 if (netif_is_l3_master(skb->dev)) { 935 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 936 if (!dev) 937 goto out; 938 } 939 940 in_dev = __in_dev_get_rcu(dev); 941 942 /* IP on this device is disabled. */ 943 if (!in_dev) 944 goto out; 945 946 net = dev_net(rt->dst.dev); 947 if (!IN_DEV_FORWARD(in_dev)) { 948 switch (rt->dst.error) { 949 case EHOSTUNREACH: 950 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 951 break; 952 953 case ENETUNREACH: 954 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 955 break; 956 } 957 goto out; 958 } 959 960 switch (rt->dst.error) { 961 case EINVAL: 962 default: 963 goto out; 964 case EHOSTUNREACH: 965 code = ICMP_HOST_UNREACH; 966 break; 967 case ENETUNREACH: 968 code = ICMP_NET_UNREACH; 969 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 970 break; 971 case EACCES: 972 code = ICMP_PKT_FILTERED; 973 break; 974 } 975 976 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 977 l3mdev_master_ifindex(skb->dev), 1); 978 979 send = true; 980 if (peer) { 981 now = jiffies; 982 peer->rate_tokens += now - peer->rate_last; 983 if (peer->rate_tokens > ip_rt_error_burst) 984 peer->rate_tokens = ip_rt_error_burst; 985 peer->rate_last = now; 986 if (peer->rate_tokens >= ip_rt_error_cost) 987 peer->rate_tokens -= ip_rt_error_cost; 988 else 989 send = false; 990 inet_putpeer(peer); 991 } 992 if (send) 993 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 994 995 out: kfree_skb(skb); 996 return 0; 997 } 998 999 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1000 { 1001 struct dst_entry *dst = &rt->dst; 1002 struct net *net = dev_net(dst->dev); 1003 struct fib_result res; 1004 bool lock = false; 1005 u32 old_mtu; 1006 1007 if (ip_mtu_locked(dst)) 1008 return; 1009 1010 old_mtu = ipv4_mtu(dst); 1011 if (old_mtu < mtu) 1012 return; 1013 1014 if (mtu < ip_rt_min_pmtu) { 1015 lock = true; 1016 mtu = min(old_mtu, ip_rt_min_pmtu); 1017 } 1018 1019 if (rt->rt_pmtu == mtu && !lock && 1020 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1021 return; 1022 1023 rcu_read_lock(); 1024 if (fib_lookup(net, fl4, &res, 0) == 0) { 1025 struct fib_nh_common *nhc; 1026 1027 fib_select_path(net, &res, fl4, NULL); 1028 nhc = FIB_RES_NHC(res); 1029 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1030 jiffies + ip_rt_mtu_expires); 1031 } 1032 rcu_read_unlock(); 1033 } 1034 1035 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1036 struct sk_buff *skb, u32 mtu, 1037 bool confirm_neigh) 1038 { 1039 struct rtable *rt = (struct rtable *) dst; 1040 struct flowi4 fl4; 1041 1042 ip_rt_build_flow_key(&fl4, sk, skb); 1043 1044 /* Don't make lookup fail for bridged encapsulations */ 1045 if (skb && netif_is_any_bridge_port(skb->dev)) 1046 fl4.flowi4_oif = 0; 1047 1048 __ip_rt_update_pmtu(rt, &fl4, mtu); 1049 } 1050 1051 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1052 int oif, u8 protocol) 1053 { 1054 const struct iphdr *iph = (const struct iphdr *)skb->data; 1055 struct flowi4 fl4; 1056 struct rtable *rt; 1057 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1058 1059 __build_flow_key(net, &fl4, NULL, iph, oif, 1060 RT_TOS(iph->tos), protocol, mark, 0); 1061 rt = __ip_route_output_key(net, &fl4); 1062 if (!IS_ERR(rt)) { 1063 __ip_rt_update_pmtu(rt, &fl4, mtu); 1064 ip_rt_put(rt); 1065 } 1066 } 1067 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1068 1069 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1070 { 1071 const struct iphdr *iph = (const struct iphdr *)skb->data; 1072 struct flowi4 fl4; 1073 struct rtable *rt; 1074 1075 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1076 1077 if (!fl4.flowi4_mark) 1078 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1079 1080 rt = __ip_route_output_key(sock_net(sk), &fl4); 1081 if (!IS_ERR(rt)) { 1082 __ip_rt_update_pmtu(rt, &fl4, mtu); 1083 ip_rt_put(rt); 1084 } 1085 } 1086 1087 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1088 { 1089 const struct iphdr *iph = (const struct iphdr *)skb->data; 1090 struct flowi4 fl4; 1091 struct rtable *rt; 1092 struct dst_entry *odst = NULL; 1093 bool new = false; 1094 struct net *net = sock_net(sk); 1095 1096 bh_lock_sock(sk); 1097 1098 if (!ip_sk_accept_pmtu(sk)) 1099 goto out; 1100 1101 odst = sk_dst_get(sk); 1102 1103 if (sock_owned_by_user(sk) || !odst) { 1104 __ipv4_sk_update_pmtu(skb, sk, mtu); 1105 goto out; 1106 } 1107 1108 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1109 1110 rt = (struct rtable *)odst; 1111 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1113 if (IS_ERR(rt)) 1114 goto out; 1115 1116 new = true; 1117 } 1118 1119 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu); 1120 1121 if (!dst_check(&rt->dst, 0)) { 1122 if (new) 1123 dst_release(&rt->dst); 1124 1125 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1126 if (IS_ERR(rt)) 1127 goto out; 1128 1129 new = true; 1130 } 1131 1132 if (new) 1133 sk_dst_set(sk, &rt->dst); 1134 1135 out: 1136 bh_unlock_sock(sk); 1137 dst_release(odst); 1138 } 1139 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1140 1141 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1142 int oif, u8 protocol) 1143 { 1144 const struct iphdr *iph = (const struct iphdr *)skb->data; 1145 struct flowi4 fl4; 1146 struct rtable *rt; 1147 1148 __build_flow_key(net, &fl4, NULL, iph, oif, 1149 RT_TOS(iph->tos), protocol, 0, 0); 1150 rt = __ip_route_output_key(net, &fl4); 1151 if (!IS_ERR(rt)) { 1152 __ip_do_redirect(rt, skb, &fl4, false); 1153 ip_rt_put(rt); 1154 } 1155 } 1156 EXPORT_SYMBOL_GPL(ipv4_redirect); 1157 1158 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1159 { 1160 const struct iphdr *iph = (const struct iphdr *)skb->data; 1161 struct flowi4 fl4; 1162 struct rtable *rt; 1163 struct net *net = sock_net(sk); 1164 1165 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1166 rt = __ip_route_output_key(net, &fl4); 1167 if (!IS_ERR(rt)) { 1168 __ip_do_redirect(rt, skb, &fl4, false); 1169 ip_rt_put(rt); 1170 } 1171 } 1172 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1173 1174 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst, 1175 u32 cookie) 1176 { 1177 struct rtable *rt = (struct rtable *) dst; 1178 1179 /* All IPV4 dsts are created with ->obsolete set to the value 1180 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1181 * into this function always. 1182 * 1183 * When a PMTU/redirect information update invalidates a route, 1184 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1185 * DST_OBSOLETE_DEAD. 1186 */ 1187 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1188 return NULL; 1189 return dst; 1190 } 1191 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check); 1192 1193 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1194 { 1195 struct ip_options opt; 1196 int res; 1197 1198 /* Recompile ip options since IPCB may not be valid anymore. 1199 * Also check we have a reasonable ipv4 header. 1200 */ 1201 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1202 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1203 return; 1204 1205 memset(&opt, 0, sizeof(opt)); 1206 if (ip_hdr(skb)->ihl > 5) { 1207 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1208 return; 1209 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1210 1211 rcu_read_lock(); 1212 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1213 rcu_read_unlock(); 1214 1215 if (res) 1216 return; 1217 } 1218 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1219 } 1220 1221 static void ipv4_link_failure(struct sk_buff *skb) 1222 { 1223 struct rtable *rt; 1224 1225 ipv4_send_dest_unreach(skb); 1226 1227 rt = skb_rtable(skb); 1228 if (rt) 1229 dst_set_expires(&rt->dst, 0); 1230 } 1231 1232 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1233 { 1234 pr_debug("%s: %pI4 -> %pI4, %s\n", 1235 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1236 skb->dev ? skb->dev->name : "?"); 1237 kfree_skb(skb); 1238 WARN_ON(1); 1239 return 0; 1240 } 1241 1242 /* 1243 * We do not cache source address of outgoing interface, 1244 * because it is used only by IP RR, TS and SRR options, 1245 * so that it out of fast path. 1246 * 1247 * BTW remember: "addr" is allowed to be not aligned 1248 * in IP options! 1249 */ 1250 1251 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1252 { 1253 __be32 src; 1254 1255 if (rt_is_output_route(rt)) 1256 src = ip_hdr(skb)->saddr; 1257 else { 1258 struct fib_result res; 1259 struct iphdr *iph = ip_hdr(skb); 1260 struct flowi4 fl4 = { 1261 .daddr = iph->daddr, 1262 .saddr = iph->saddr, 1263 .flowi4_tos = RT_TOS(iph->tos), 1264 .flowi4_oif = rt->dst.dev->ifindex, 1265 .flowi4_iif = skb->dev->ifindex, 1266 .flowi4_mark = skb->mark, 1267 }; 1268 1269 rcu_read_lock(); 1270 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1271 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1272 else 1273 src = inet_select_addr(rt->dst.dev, 1274 rt_nexthop(rt, iph->daddr), 1275 RT_SCOPE_UNIVERSE); 1276 rcu_read_unlock(); 1277 } 1278 memcpy(addr, &src, 4); 1279 } 1280 1281 #ifdef CONFIG_IP_ROUTE_CLASSID 1282 static void set_class_tag(struct rtable *rt, u32 tag) 1283 { 1284 if (!(rt->dst.tclassid & 0xFFFF)) 1285 rt->dst.tclassid |= tag & 0xFFFF; 1286 if (!(rt->dst.tclassid & 0xFFFF0000)) 1287 rt->dst.tclassid |= tag & 0xFFFF0000; 1288 } 1289 #endif 1290 1291 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1292 { 1293 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1294 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1295 ip_rt_min_advmss); 1296 1297 return min(advmss, IPV4_MAX_PMTU - header_size); 1298 } 1299 1300 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst) 1301 { 1302 const struct rtable *rt = (const struct rtable *)dst; 1303 unsigned int mtu = rt->rt_pmtu; 1304 1305 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1306 mtu = dst_metric_raw(dst, RTAX_MTU); 1307 1308 if (mtu) 1309 return mtu; 1310 1311 mtu = READ_ONCE(dst->dev->mtu); 1312 1313 if (unlikely(ip_mtu_locked(dst))) { 1314 if (rt->rt_uses_gateway && mtu > 576) 1315 mtu = 576; 1316 } 1317 1318 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1319 1320 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1321 } 1322 EXPORT_INDIRECT_CALLABLE(ipv4_mtu); 1323 1324 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1325 { 1326 struct fnhe_hash_bucket *hash; 1327 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1328 u32 hval = fnhe_hashfun(daddr); 1329 1330 spin_lock_bh(&fnhe_lock); 1331 1332 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1333 lockdep_is_held(&fnhe_lock)); 1334 hash += hval; 1335 1336 fnhe_p = &hash->chain; 1337 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1338 while (fnhe) { 1339 if (fnhe->fnhe_daddr == daddr) { 1340 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1341 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1342 /* set fnhe_daddr to 0 to ensure it won't bind with 1343 * new dsts in rt_bind_exception(). 1344 */ 1345 fnhe->fnhe_daddr = 0; 1346 fnhe_flush_routes(fnhe); 1347 kfree_rcu(fnhe, rcu); 1348 break; 1349 } 1350 fnhe_p = &fnhe->fnhe_next; 1351 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1352 lockdep_is_held(&fnhe_lock)); 1353 } 1354 1355 spin_unlock_bh(&fnhe_lock); 1356 } 1357 1358 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1359 __be32 daddr) 1360 { 1361 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1362 struct fib_nh_exception *fnhe; 1363 u32 hval; 1364 1365 if (!hash) 1366 return NULL; 1367 1368 hval = fnhe_hashfun(daddr); 1369 1370 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1371 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1372 if (fnhe->fnhe_daddr == daddr) { 1373 if (fnhe->fnhe_expires && 1374 time_after(jiffies, fnhe->fnhe_expires)) { 1375 ip_del_fnhe(nhc, daddr); 1376 break; 1377 } 1378 return fnhe; 1379 } 1380 } 1381 return NULL; 1382 } 1383 1384 /* MTU selection: 1385 * 1. mtu on route is locked - use it 1386 * 2. mtu from nexthop exception 1387 * 3. mtu from egress device 1388 */ 1389 1390 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1391 { 1392 struct fib_nh_common *nhc = res->nhc; 1393 struct net_device *dev = nhc->nhc_dev; 1394 struct fib_info *fi = res->fi; 1395 u32 mtu = 0; 1396 1397 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1398 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1399 mtu = fi->fib_mtu; 1400 1401 if (likely(!mtu)) { 1402 struct fib_nh_exception *fnhe; 1403 1404 fnhe = find_exception(nhc, daddr); 1405 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1406 mtu = fnhe->fnhe_pmtu; 1407 } 1408 1409 if (likely(!mtu)) 1410 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1411 1412 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1413 } 1414 1415 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1416 __be32 daddr, const bool do_cache) 1417 { 1418 bool ret = false; 1419 1420 spin_lock_bh(&fnhe_lock); 1421 1422 if (daddr == fnhe->fnhe_daddr) { 1423 struct rtable __rcu **porig; 1424 struct rtable *orig; 1425 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1426 1427 if (rt_is_input_route(rt)) 1428 porig = &fnhe->fnhe_rth_input; 1429 else 1430 porig = &fnhe->fnhe_rth_output; 1431 orig = rcu_dereference(*porig); 1432 1433 if (fnhe->fnhe_genid != genid) { 1434 fnhe->fnhe_genid = genid; 1435 fnhe->fnhe_gw = 0; 1436 fnhe->fnhe_pmtu = 0; 1437 fnhe->fnhe_expires = 0; 1438 fnhe->fnhe_mtu_locked = false; 1439 fnhe_flush_routes(fnhe); 1440 orig = NULL; 1441 } 1442 fill_route_from_fnhe(rt, fnhe); 1443 if (!rt->rt_gw4) { 1444 rt->rt_gw4 = daddr; 1445 rt->rt_gw_family = AF_INET; 1446 } 1447 1448 if (do_cache) { 1449 dst_hold(&rt->dst); 1450 rcu_assign_pointer(*porig, rt); 1451 if (orig) { 1452 dst_dev_put(&orig->dst); 1453 dst_release(&orig->dst); 1454 } 1455 ret = true; 1456 } 1457 1458 fnhe->fnhe_stamp = jiffies; 1459 } 1460 spin_unlock_bh(&fnhe_lock); 1461 1462 return ret; 1463 } 1464 1465 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1466 { 1467 struct rtable *orig, *prev, **p; 1468 bool ret = true; 1469 1470 if (rt_is_input_route(rt)) { 1471 p = (struct rtable **)&nhc->nhc_rth_input; 1472 } else { 1473 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1474 } 1475 orig = *p; 1476 1477 /* hold dst before doing cmpxchg() to avoid race condition 1478 * on this dst 1479 */ 1480 dst_hold(&rt->dst); 1481 prev = cmpxchg(p, orig, rt); 1482 if (prev == orig) { 1483 if (orig) { 1484 rt_add_uncached_list(orig); 1485 dst_release(&orig->dst); 1486 } 1487 } else { 1488 dst_release(&rt->dst); 1489 ret = false; 1490 } 1491 1492 return ret; 1493 } 1494 1495 struct uncached_list { 1496 spinlock_t lock; 1497 struct list_head head; 1498 }; 1499 1500 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1501 1502 void rt_add_uncached_list(struct rtable *rt) 1503 { 1504 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1505 1506 rt->rt_uncached_list = ul; 1507 1508 spin_lock_bh(&ul->lock); 1509 list_add_tail(&rt->rt_uncached, &ul->head); 1510 spin_unlock_bh(&ul->lock); 1511 } 1512 1513 void rt_del_uncached_list(struct rtable *rt) 1514 { 1515 if (!list_empty(&rt->rt_uncached)) { 1516 struct uncached_list *ul = rt->rt_uncached_list; 1517 1518 spin_lock_bh(&ul->lock); 1519 list_del(&rt->rt_uncached); 1520 spin_unlock_bh(&ul->lock); 1521 } 1522 } 1523 1524 static void ipv4_dst_destroy(struct dst_entry *dst) 1525 { 1526 struct rtable *rt = (struct rtable *)dst; 1527 1528 ip_dst_metrics_put(dst); 1529 rt_del_uncached_list(rt); 1530 } 1531 1532 void rt_flush_dev(struct net_device *dev) 1533 { 1534 struct rtable *rt; 1535 int cpu; 1536 1537 for_each_possible_cpu(cpu) { 1538 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1539 1540 spin_lock_bh(&ul->lock); 1541 list_for_each_entry(rt, &ul->head, rt_uncached) { 1542 if (rt->dst.dev != dev) 1543 continue; 1544 rt->dst.dev = blackhole_netdev; 1545 dev_hold(rt->dst.dev); 1546 dev_put(dev); 1547 } 1548 spin_unlock_bh(&ul->lock); 1549 } 1550 } 1551 1552 static bool rt_cache_valid(const struct rtable *rt) 1553 { 1554 return rt && 1555 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1556 !rt_is_expired(rt); 1557 } 1558 1559 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1560 const struct fib_result *res, 1561 struct fib_nh_exception *fnhe, 1562 struct fib_info *fi, u16 type, u32 itag, 1563 const bool do_cache) 1564 { 1565 bool cached = false; 1566 1567 if (fi) { 1568 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1569 1570 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1571 rt->rt_uses_gateway = 1; 1572 rt->rt_gw_family = nhc->nhc_gw_family; 1573 /* only INET and INET6 are supported */ 1574 if (likely(nhc->nhc_gw_family == AF_INET)) 1575 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1576 else 1577 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1578 } 1579 1580 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1581 1582 #ifdef CONFIG_IP_ROUTE_CLASSID 1583 if (nhc->nhc_family == AF_INET) { 1584 struct fib_nh *nh; 1585 1586 nh = container_of(nhc, struct fib_nh, nh_common); 1587 rt->dst.tclassid = nh->nh_tclassid; 1588 } 1589 #endif 1590 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1591 if (unlikely(fnhe)) 1592 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1593 else if (do_cache) 1594 cached = rt_cache_route(nhc, rt); 1595 if (unlikely(!cached)) { 1596 /* Routes we intend to cache in nexthop exception or 1597 * FIB nexthop have the DST_NOCACHE bit clear. 1598 * However, if we are unsuccessful at storing this 1599 * route into the cache we really need to set it. 1600 */ 1601 if (!rt->rt_gw4) { 1602 rt->rt_gw_family = AF_INET; 1603 rt->rt_gw4 = daddr; 1604 } 1605 rt_add_uncached_list(rt); 1606 } 1607 } else 1608 rt_add_uncached_list(rt); 1609 1610 #ifdef CONFIG_IP_ROUTE_CLASSID 1611 #ifdef CONFIG_IP_MULTIPLE_TABLES 1612 set_class_tag(rt, res->tclassid); 1613 #endif 1614 set_class_tag(rt, itag); 1615 #endif 1616 } 1617 1618 struct rtable *rt_dst_alloc(struct net_device *dev, 1619 unsigned int flags, u16 type, 1620 bool nopolicy, bool noxfrm) 1621 { 1622 struct rtable *rt; 1623 1624 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1625 (nopolicy ? DST_NOPOLICY : 0) | 1626 (noxfrm ? DST_NOXFRM : 0)); 1627 1628 if (rt) { 1629 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1630 rt->rt_flags = flags; 1631 rt->rt_type = type; 1632 rt->rt_is_input = 0; 1633 rt->rt_iif = 0; 1634 rt->rt_pmtu = 0; 1635 rt->rt_mtu_locked = 0; 1636 rt->rt_uses_gateway = 0; 1637 rt->rt_gw_family = 0; 1638 rt->rt_gw4 = 0; 1639 INIT_LIST_HEAD(&rt->rt_uncached); 1640 1641 rt->dst.output = ip_output; 1642 if (flags & RTCF_LOCAL) 1643 rt->dst.input = ip_local_deliver; 1644 } 1645 1646 return rt; 1647 } 1648 EXPORT_SYMBOL(rt_dst_alloc); 1649 1650 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1651 { 1652 struct rtable *new_rt; 1653 1654 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1655 rt->dst.flags); 1656 1657 if (new_rt) { 1658 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1659 new_rt->rt_flags = rt->rt_flags; 1660 new_rt->rt_type = rt->rt_type; 1661 new_rt->rt_is_input = rt->rt_is_input; 1662 new_rt->rt_iif = rt->rt_iif; 1663 new_rt->rt_pmtu = rt->rt_pmtu; 1664 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1665 new_rt->rt_gw_family = rt->rt_gw_family; 1666 if (rt->rt_gw_family == AF_INET) 1667 new_rt->rt_gw4 = rt->rt_gw4; 1668 else if (rt->rt_gw_family == AF_INET6) 1669 new_rt->rt_gw6 = rt->rt_gw6; 1670 INIT_LIST_HEAD(&new_rt->rt_uncached); 1671 1672 new_rt->dst.input = rt->dst.input; 1673 new_rt->dst.output = rt->dst.output; 1674 new_rt->dst.error = rt->dst.error; 1675 new_rt->dst.lastuse = jiffies; 1676 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1677 } 1678 return new_rt; 1679 } 1680 EXPORT_SYMBOL(rt_dst_clone); 1681 1682 /* called in rcu_read_lock() section */ 1683 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1684 u8 tos, struct net_device *dev, 1685 struct in_device *in_dev, u32 *itag) 1686 { 1687 int err; 1688 1689 /* Primary sanity checks. */ 1690 if (!in_dev) 1691 return -EINVAL; 1692 1693 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1694 skb->protocol != htons(ETH_P_IP)) 1695 return -EINVAL; 1696 1697 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1698 return -EINVAL; 1699 1700 if (ipv4_is_zeronet(saddr)) { 1701 if (!ipv4_is_local_multicast(daddr) && 1702 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1703 return -EINVAL; 1704 } else { 1705 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1706 in_dev, itag); 1707 if (err < 0) 1708 return err; 1709 } 1710 return 0; 1711 } 1712 1713 /* called in rcu_read_lock() section */ 1714 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1715 u8 tos, struct net_device *dev, int our) 1716 { 1717 struct in_device *in_dev = __in_dev_get_rcu(dev); 1718 unsigned int flags = RTCF_MULTICAST; 1719 struct rtable *rth; 1720 u32 itag = 0; 1721 int err; 1722 1723 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1724 if (err) 1725 return err; 1726 1727 if (our) 1728 flags |= RTCF_LOCAL; 1729 1730 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1731 IN_DEV_ORCONF(in_dev, NOPOLICY), false); 1732 if (!rth) 1733 return -ENOBUFS; 1734 1735 #ifdef CONFIG_IP_ROUTE_CLASSID 1736 rth->dst.tclassid = itag; 1737 #endif 1738 rth->dst.output = ip_rt_bug; 1739 rth->rt_is_input= 1; 1740 1741 #ifdef CONFIG_IP_MROUTE 1742 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1743 rth->dst.input = ip_mr_input; 1744 #endif 1745 RT_CACHE_STAT_INC(in_slow_mc); 1746 1747 skb_dst_set(skb, &rth->dst); 1748 return 0; 1749 } 1750 1751 1752 static void ip_handle_martian_source(struct net_device *dev, 1753 struct in_device *in_dev, 1754 struct sk_buff *skb, 1755 __be32 daddr, 1756 __be32 saddr) 1757 { 1758 RT_CACHE_STAT_INC(in_martian_src); 1759 #ifdef CONFIG_IP_ROUTE_VERBOSE 1760 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1761 /* 1762 * RFC1812 recommendation, if source is martian, 1763 * the only hint is MAC header. 1764 */ 1765 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1766 &daddr, &saddr, dev->name); 1767 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1768 print_hex_dump(KERN_WARNING, "ll header: ", 1769 DUMP_PREFIX_OFFSET, 16, 1, 1770 skb_mac_header(skb), 1771 dev->hard_header_len, false); 1772 } 1773 } 1774 #endif 1775 } 1776 1777 /* called in rcu_read_lock() section */ 1778 static int __mkroute_input(struct sk_buff *skb, 1779 const struct fib_result *res, 1780 struct in_device *in_dev, 1781 __be32 daddr, __be32 saddr, u32 tos) 1782 { 1783 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1784 struct net_device *dev = nhc->nhc_dev; 1785 struct fib_nh_exception *fnhe; 1786 struct rtable *rth; 1787 int err; 1788 struct in_device *out_dev; 1789 bool do_cache; 1790 u32 itag = 0; 1791 1792 /* get a working reference to the output device */ 1793 out_dev = __in_dev_get_rcu(dev); 1794 if (!out_dev) { 1795 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1796 return -EINVAL; 1797 } 1798 1799 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1800 in_dev->dev, in_dev, &itag); 1801 if (err < 0) { 1802 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1803 saddr); 1804 1805 goto cleanup; 1806 } 1807 1808 do_cache = res->fi && !itag; 1809 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1810 skb->protocol == htons(ETH_P_IP)) { 1811 __be32 gw; 1812 1813 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1814 if (IN_DEV_SHARED_MEDIA(out_dev) || 1815 inet_addr_onlink(out_dev, saddr, gw)) 1816 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1817 } 1818 1819 if (skb->protocol != htons(ETH_P_IP)) { 1820 /* Not IP (i.e. ARP). Do not create route, if it is 1821 * invalid for proxy arp. DNAT routes are always valid. 1822 * 1823 * Proxy arp feature have been extended to allow, ARP 1824 * replies back to the same interface, to support 1825 * Private VLAN switch technologies. See arp.c. 1826 */ 1827 if (out_dev == in_dev && 1828 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1829 err = -EINVAL; 1830 goto cleanup; 1831 } 1832 } 1833 1834 fnhe = find_exception(nhc, daddr); 1835 if (do_cache) { 1836 if (fnhe) 1837 rth = rcu_dereference(fnhe->fnhe_rth_input); 1838 else 1839 rth = rcu_dereference(nhc->nhc_rth_input); 1840 if (rt_cache_valid(rth)) { 1841 skb_dst_set_noref(skb, &rth->dst); 1842 goto out; 1843 } 1844 } 1845 1846 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1847 IN_DEV_ORCONF(in_dev, NOPOLICY), 1848 IN_DEV_ORCONF(out_dev, NOXFRM)); 1849 if (!rth) { 1850 err = -ENOBUFS; 1851 goto cleanup; 1852 } 1853 1854 rth->rt_is_input = 1; 1855 RT_CACHE_STAT_INC(in_slow_tot); 1856 1857 rth->dst.input = ip_forward; 1858 1859 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1860 do_cache); 1861 lwtunnel_set_redirect(&rth->dst); 1862 skb_dst_set(skb, &rth->dst); 1863 out: 1864 err = 0; 1865 cleanup: 1866 return err; 1867 } 1868 1869 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1870 /* To make ICMP packets follow the right flow, the multipath hash is 1871 * calculated from the inner IP addresses. 1872 */ 1873 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1874 struct flow_keys *hash_keys) 1875 { 1876 const struct iphdr *outer_iph = ip_hdr(skb); 1877 const struct iphdr *key_iph = outer_iph; 1878 const struct iphdr *inner_iph; 1879 const struct icmphdr *icmph; 1880 struct iphdr _inner_iph; 1881 struct icmphdr _icmph; 1882 1883 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1884 goto out; 1885 1886 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1887 goto out; 1888 1889 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1890 &_icmph); 1891 if (!icmph) 1892 goto out; 1893 1894 if (!icmp_is_err(icmph->type)) 1895 goto out; 1896 1897 inner_iph = skb_header_pointer(skb, 1898 outer_iph->ihl * 4 + sizeof(_icmph), 1899 sizeof(_inner_iph), &_inner_iph); 1900 if (!inner_iph) 1901 goto out; 1902 1903 key_iph = inner_iph; 1904 out: 1905 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1906 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1907 } 1908 1909 /* if skb is set it will be used and fl4 can be NULL */ 1910 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1911 const struct sk_buff *skb, struct flow_keys *flkeys) 1912 { 1913 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1914 struct flow_keys hash_keys; 1915 u32 mhash; 1916 1917 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1918 case 0: 1919 memset(&hash_keys, 0, sizeof(hash_keys)); 1920 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1921 if (skb) { 1922 ip_multipath_l3_keys(skb, &hash_keys); 1923 } else { 1924 hash_keys.addrs.v4addrs.src = fl4->saddr; 1925 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1926 } 1927 break; 1928 case 1: 1929 /* skb is currently provided only when forwarding */ 1930 if (skb) { 1931 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1932 struct flow_keys keys; 1933 1934 /* short-circuit if we already have L4 hash present */ 1935 if (skb->l4_hash) 1936 return skb_get_hash_raw(skb) >> 1; 1937 1938 memset(&hash_keys, 0, sizeof(hash_keys)); 1939 1940 if (!flkeys) { 1941 skb_flow_dissect_flow_keys(skb, &keys, flag); 1942 flkeys = &keys; 1943 } 1944 1945 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1946 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1947 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1948 hash_keys.ports.src = flkeys->ports.src; 1949 hash_keys.ports.dst = flkeys->ports.dst; 1950 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1951 } else { 1952 memset(&hash_keys, 0, sizeof(hash_keys)); 1953 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1954 hash_keys.addrs.v4addrs.src = fl4->saddr; 1955 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1956 hash_keys.ports.src = fl4->fl4_sport; 1957 hash_keys.ports.dst = fl4->fl4_dport; 1958 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1959 } 1960 break; 1961 case 2: 1962 memset(&hash_keys, 0, sizeof(hash_keys)); 1963 /* skb is currently provided only when forwarding */ 1964 if (skb) { 1965 struct flow_keys keys; 1966 1967 skb_flow_dissect_flow_keys(skb, &keys, 0); 1968 /* Inner can be v4 or v6 */ 1969 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1970 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1971 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1972 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1973 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1974 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1975 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1976 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1977 hash_keys.tags.flow_label = keys.tags.flow_label; 1978 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1979 } else { 1980 /* Same as case 0 */ 1981 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1982 ip_multipath_l3_keys(skb, &hash_keys); 1983 } 1984 } else { 1985 /* Same as case 0 */ 1986 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1987 hash_keys.addrs.v4addrs.src = fl4->saddr; 1988 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1989 } 1990 break; 1991 } 1992 mhash = flow_hash_from_keys(&hash_keys); 1993 1994 if (multipath_hash) 1995 mhash = jhash_2words(mhash, multipath_hash, 0); 1996 1997 return mhash >> 1; 1998 } 1999 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2000 2001 static int ip_mkroute_input(struct sk_buff *skb, 2002 struct fib_result *res, 2003 struct in_device *in_dev, 2004 __be32 daddr, __be32 saddr, u32 tos, 2005 struct flow_keys *hkeys) 2006 { 2007 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2008 if (res->fi && fib_info_num_path(res->fi) > 1) { 2009 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2010 2011 fib_select_multipath(res, h); 2012 } 2013 #endif 2014 2015 /* create a routing cache entry */ 2016 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2017 } 2018 2019 /* Implements all the saddr-related checks as ip_route_input_slow(), 2020 * assuming daddr is valid and the destination is not a local broadcast one. 2021 * Uses the provided hint instead of performing a route lookup. 2022 */ 2023 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2024 u8 tos, struct net_device *dev, 2025 const struct sk_buff *hint) 2026 { 2027 struct in_device *in_dev = __in_dev_get_rcu(dev); 2028 struct rtable *rt = skb_rtable(hint); 2029 struct net *net = dev_net(dev); 2030 int err = -EINVAL; 2031 u32 tag = 0; 2032 2033 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2034 goto martian_source; 2035 2036 if (ipv4_is_zeronet(saddr)) 2037 goto martian_source; 2038 2039 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2040 goto martian_source; 2041 2042 if (rt->rt_type != RTN_LOCAL) 2043 goto skip_validate_source; 2044 2045 tos &= IPTOS_RT_MASK; 2046 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag); 2047 if (err < 0) 2048 goto martian_source; 2049 2050 skip_validate_source: 2051 skb_dst_copy(skb, hint); 2052 return 0; 2053 2054 martian_source: 2055 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2056 return err; 2057 } 2058 2059 /* 2060 * NOTE. We drop all the packets that has local source 2061 * addresses, because every properly looped back packet 2062 * must have correct destination already attached by output routine. 2063 * Changes in the enforced policies must be applied also to 2064 * ip_route_use_hint(). 2065 * 2066 * Such approach solves two big problems: 2067 * 1. Not simplex devices are handled properly. 2068 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2069 * called with rcu_read_lock() 2070 */ 2071 2072 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2073 u8 tos, struct net_device *dev, 2074 struct fib_result *res) 2075 { 2076 struct in_device *in_dev = __in_dev_get_rcu(dev); 2077 struct flow_keys *flkeys = NULL, _flkeys; 2078 struct net *net = dev_net(dev); 2079 struct ip_tunnel_info *tun_info; 2080 int err = -EINVAL; 2081 unsigned int flags = 0; 2082 u32 itag = 0; 2083 struct rtable *rth; 2084 struct flowi4 fl4; 2085 bool do_cache = true; 2086 2087 /* IP on this device is disabled. */ 2088 2089 if (!in_dev) 2090 goto out; 2091 2092 /* Check for the most weird martians, which can be not detected 2093 * by fib_lookup. 2094 */ 2095 2096 tun_info = skb_tunnel_info(skb); 2097 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2098 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2099 else 2100 fl4.flowi4_tun_key.tun_id = 0; 2101 skb_dst_drop(skb); 2102 2103 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2104 goto martian_source; 2105 2106 res->fi = NULL; 2107 res->table = NULL; 2108 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2109 goto brd_input; 2110 2111 /* Accept zero addresses only to limited broadcast; 2112 * I even do not know to fix it or not. Waiting for complains :-) 2113 */ 2114 if (ipv4_is_zeronet(saddr)) 2115 goto martian_source; 2116 2117 if (ipv4_is_zeronet(daddr)) 2118 goto martian_destination; 2119 2120 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2121 * and call it once if daddr or/and saddr are loopback addresses 2122 */ 2123 if (ipv4_is_loopback(daddr)) { 2124 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2125 goto martian_destination; 2126 } else if (ipv4_is_loopback(saddr)) { 2127 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2128 goto martian_source; 2129 } 2130 2131 /* 2132 * Now we are ready to route packet. 2133 */ 2134 fl4.flowi4_oif = 0; 2135 fl4.flowi4_iif = dev->ifindex; 2136 fl4.flowi4_mark = skb->mark; 2137 fl4.flowi4_tos = tos; 2138 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2139 fl4.flowi4_flags = 0; 2140 fl4.daddr = daddr; 2141 fl4.saddr = saddr; 2142 fl4.flowi4_uid = sock_net_uid(net, NULL); 2143 fl4.flowi4_multipath_hash = 0; 2144 2145 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2146 flkeys = &_flkeys; 2147 } else { 2148 fl4.flowi4_proto = 0; 2149 fl4.fl4_sport = 0; 2150 fl4.fl4_dport = 0; 2151 } 2152 2153 err = fib_lookup(net, &fl4, res, 0); 2154 if (err != 0) { 2155 if (!IN_DEV_FORWARD(in_dev)) 2156 err = -EHOSTUNREACH; 2157 goto no_route; 2158 } 2159 2160 if (res->type == RTN_BROADCAST) { 2161 if (IN_DEV_BFORWARD(in_dev)) 2162 goto make_route; 2163 /* not do cache if bc_forwarding is enabled */ 2164 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2165 do_cache = false; 2166 goto brd_input; 2167 } 2168 2169 if (res->type == RTN_LOCAL) { 2170 err = fib_validate_source(skb, saddr, daddr, tos, 2171 0, dev, in_dev, &itag); 2172 if (err < 0) 2173 goto martian_source; 2174 goto local_input; 2175 } 2176 2177 if (!IN_DEV_FORWARD(in_dev)) { 2178 err = -EHOSTUNREACH; 2179 goto no_route; 2180 } 2181 if (res->type != RTN_UNICAST) 2182 goto martian_destination; 2183 2184 make_route: 2185 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2186 out: return err; 2187 2188 brd_input: 2189 if (skb->protocol != htons(ETH_P_IP)) 2190 goto e_inval; 2191 2192 if (!ipv4_is_zeronet(saddr)) { 2193 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2194 in_dev, &itag); 2195 if (err < 0) 2196 goto martian_source; 2197 } 2198 flags |= RTCF_BROADCAST; 2199 res->type = RTN_BROADCAST; 2200 RT_CACHE_STAT_INC(in_brd); 2201 2202 local_input: 2203 do_cache &= res->fi && !itag; 2204 if (do_cache) { 2205 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2206 2207 rth = rcu_dereference(nhc->nhc_rth_input); 2208 if (rt_cache_valid(rth)) { 2209 skb_dst_set_noref(skb, &rth->dst); 2210 err = 0; 2211 goto out; 2212 } 2213 } 2214 2215 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2216 flags | RTCF_LOCAL, res->type, 2217 IN_DEV_ORCONF(in_dev, NOPOLICY), false); 2218 if (!rth) 2219 goto e_nobufs; 2220 2221 rth->dst.output= ip_rt_bug; 2222 #ifdef CONFIG_IP_ROUTE_CLASSID 2223 rth->dst.tclassid = itag; 2224 #endif 2225 rth->rt_is_input = 1; 2226 2227 RT_CACHE_STAT_INC(in_slow_tot); 2228 if (res->type == RTN_UNREACHABLE) { 2229 rth->dst.input= ip_error; 2230 rth->dst.error= -err; 2231 rth->rt_flags &= ~RTCF_LOCAL; 2232 } 2233 2234 if (do_cache) { 2235 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2236 2237 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2238 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2239 WARN_ON(rth->dst.input == lwtunnel_input); 2240 rth->dst.lwtstate->orig_input = rth->dst.input; 2241 rth->dst.input = lwtunnel_input; 2242 } 2243 2244 if (unlikely(!rt_cache_route(nhc, rth))) 2245 rt_add_uncached_list(rth); 2246 } 2247 skb_dst_set(skb, &rth->dst); 2248 err = 0; 2249 goto out; 2250 2251 no_route: 2252 RT_CACHE_STAT_INC(in_no_route); 2253 res->type = RTN_UNREACHABLE; 2254 res->fi = NULL; 2255 res->table = NULL; 2256 goto local_input; 2257 2258 /* 2259 * Do not cache martian addresses: they should be logged (RFC1812) 2260 */ 2261 martian_destination: 2262 RT_CACHE_STAT_INC(in_martian_dst); 2263 #ifdef CONFIG_IP_ROUTE_VERBOSE 2264 if (IN_DEV_LOG_MARTIANS(in_dev)) 2265 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2266 &daddr, &saddr, dev->name); 2267 #endif 2268 2269 e_inval: 2270 err = -EINVAL; 2271 goto out; 2272 2273 e_nobufs: 2274 err = -ENOBUFS; 2275 goto out; 2276 2277 martian_source: 2278 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2279 goto out; 2280 } 2281 2282 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2283 u8 tos, struct net_device *dev) 2284 { 2285 struct fib_result res; 2286 int err; 2287 2288 tos &= IPTOS_RT_MASK; 2289 rcu_read_lock(); 2290 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2291 rcu_read_unlock(); 2292 2293 return err; 2294 } 2295 EXPORT_SYMBOL(ip_route_input_noref); 2296 2297 /* called with rcu_read_lock held */ 2298 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2299 u8 tos, struct net_device *dev, struct fib_result *res) 2300 { 2301 /* Multicast recognition logic is moved from route cache to here. 2302 * The problem was that too many Ethernet cards have broken/missing 2303 * hardware multicast filters :-( As result the host on multicasting 2304 * network acquires a lot of useless route cache entries, sort of 2305 * SDR messages from all the world. Now we try to get rid of them. 2306 * Really, provided software IP multicast filter is organized 2307 * reasonably (at least, hashed), it does not result in a slowdown 2308 * comparing with route cache reject entries. 2309 * Note, that multicast routers are not affected, because 2310 * route cache entry is created eventually. 2311 */ 2312 if (ipv4_is_multicast(daddr)) { 2313 struct in_device *in_dev = __in_dev_get_rcu(dev); 2314 int our = 0; 2315 int err = -EINVAL; 2316 2317 if (!in_dev) 2318 return err; 2319 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2320 ip_hdr(skb)->protocol); 2321 2322 /* check l3 master if no match yet */ 2323 if (!our && netif_is_l3_slave(dev)) { 2324 struct in_device *l3_in_dev; 2325 2326 l3_in_dev = __in_dev_get_rcu(skb->dev); 2327 if (l3_in_dev) 2328 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2329 ip_hdr(skb)->protocol); 2330 } 2331 2332 if (our 2333 #ifdef CONFIG_IP_MROUTE 2334 || 2335 (!ipv4_is_local_multicast(daddr) && 2336 IN_DEV_MFORWARD(in_dev)) 2337 #endif 2338 ) { 2339 err = ip_route_input_mc(skb, daddr, saddr, 2340 tos, dev, our); 2341 } 2342 return err; 2343 } 2344 2345 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2346 } 2347 2348 /* called with rcu_read_lock() */ 2349 static struct rtable *__mkroute_output(const struct fib_result *res, 2350 const struct flowi4 *fl4, int orig_oif, 2351 struct net_device *dev_out, 2352 unsigned int flags) 2353 { 2354 struct fib_info *fi = res->fi; 2355 struct fib_nh_exception *fnhe; 2356 struct in_device *in_dev; 2357 u16 type = res->type; 2358 struct rtable *rth; 2359 bool do_cache; 2360 2361 in_dev = __in_dev_get_rcu(dev_out); 2362 if (!in_dev) 2363 return ERR_PTR(-EINVAL); 2364 2365 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2366 if (ipv4_is_loopback(fl4->saddr) && 2367 !(dev_out->flags & IFF_LOOPBACK) && 2368 !netif_is_l3_master(dev_out)) 2369 return ERR_PTR(-EINVAL); 2370 2371 if (ipv4_is_lbcast(fl4->daddr)) 2372 type = RTN_BROADCAST; 2373 else if (ipv4_is_multicast(fl4->daddr)) 2374 type = RTN_MULTICAST; 2375 else if (ipv4_is_zeronet(fl4->daddr)) 2376 return ERR_PTR(-EINVAL); 2377 2378 if (dev_out->flags & IFF_LOOPBACK) 2379 flags |= RTCF_LOCAL; 2380 2381 do_cache = true; 2382 if (type == RTN_BROADCAST) { 2383 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2384 fi = NULL; 2385 } else if (type == RTN_MULTICAST) { 2386 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2387 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2388 fl4->flowi4_proto)) 2389 flags &= ~RTCF_LOCAL; 2390 else 2391 do_cache = false; 2392 /* If multicast route do not exist use 2393 * default one, but do not gateway in this case. 2394 * Yes, it is hack. 2395 */ 2396 if (fi && res->prefixlen < 4) 2397 fi = NULL; 2398 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2399 (orig_oif != dev_out->ifindex)) { 2400 /* For local routes that require a particular output interface 2401 * we do not want to cache the result. Caching the result 2402 * causes incorrect behaviour when there are multiple source 2403 * addresses on the interface, the end result being that if the 2404 * intended recipient is waiting on that interface for the 2405 * packet he won't receive it because it will be delivered on 2406 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2407 * be set to the loopback interface as well. 2408 */ 2409 do_cache = false; 2410 } 2411 2412 fnhe = NULL; 2413 do_cache &= fi != NULL; 2414 if (fi) { 2415 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2416 struct rtable __rcu **prth; 2417 2418 fnhe = find_exception(nhc, fl4->daddr); 2419 if (!do_cache) 2420 goto add; 2421 if (fnhe) { 2422 prth = &fnhe->fnhe_rth_output; 2423 } else { 2424 if (unlikely(fl4->flowi4_flags & 2425 FLOWI_FLAG_KNOWN_NH && 2426 !(nhc->nhc_gw_family && 2427 nhc->nhc_scope == RT_SCOPE_LINK))) { 2428 do_cache = false; 2429 goto add; 2430 } 2431 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2432 } 2433 rth = rcu_dereference(*prth); 2434 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2435 return rth; 2436 } 2437 2438 add: 2439 rth = rt_dst_alloc(dev_out, flags, type, 2440 IN_DEV_ORCONF(in_dev, NOPOLICY), 2441 IN_DEV_ORCONF(in_dev, NOXFRM)); 2442 if (!rth) 2443 return ERR_PTR(-ENOBUFS); 2444 2445 rth->rt_iif = orig_oif; 2446 2447 RT_CACHE_STAT_INC(out_slow_tot); 2448 2449 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2450 if (flags & RTCF_LOCAL && 2451 !(dev_out->flags & IFF_LOOPBACK)) { 2452 rth->dst.output = ip_mc_output; 2453 RT_CACHE_STAT_INC(out_slow_mc); 2454 } 2455 #ifdef CONFIG_IP_MROUTE 2456 if (type == RTN_MULTICAST) { 2457 if (IN_DEV_MFORWARD(in_dev) && 2458 !ipv4_is_local_multicast(fl4->daddr)) { 2459 rth->dst.input = ip_mr_input; 2460 rth->dst.output = ip_mc_output; 2461 } 2462 } 2463 #endif 2464 } 2465 2466 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2467 lwtunnel_set_redirect(&rth->dst); 2468 2469 return rth; 2470 } 2471 2472 /* 2473 * Major route resolver routine. 2474 */ 2475 2476 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2477 const struct sk_buff *skb) 2478 { 2479 __u8 tos = RT_FL_TOS(fl4); 2480 struct fib_result res = { 2481 .type = RTN_UNSPEC, 2482 .fi = NULL, 2483 .table = NULL, 2484 .tclassid = 0, 2485 }; 2486 struct rtable *rth; 2487 2488 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2489 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2490 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2491 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2492 2493 rcu_read_lock(); 2494 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2495 rcu_read_unlock(); 2496 2497 return rth; 2498 } 2499 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2500 2501 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2502 struct fib_result *res, 2503 const struct sk_buff *skb) 2504 { 2505 struct net_device *dev_out = NULL; 2506 int orig_oif = fl4->flowi4_oif; 2507 unsigned int flags = 0; 2508 struct rtable *rth; 2509 int err; 2510 2511 if (fl4->saddr) { 2512 if (ipv4_is_multicast(fl4->saddr) || 2513 ipv4_is_lbcast(fl4->saddr) || 2514 ipv4_is_zeronet(fl4->saddr)) { 2515 rth = ERR_PTR(-EINVAL); 2516 goto out; 2517 } 2518 2519 rth = ERR_PTR(-ENETUNREACH); 2520 2521 /* I removed check for oif == dev_out->oif here. 2522 * It was wrong for two reasons: 2523 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2524 * is assigned to multiple interfaces. 2525 * 2. Moreover, we are allowed to send packets with saddr 2526 * of another iface. --ANK 2527 */ 2528 2529 if (fl4->flowi4_oif == 0 && 2530 (ipv4_is_multicast(fl4->daddr) || 2531 ipv4_is_lbcast(fl4->daddr))) { 2532 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2533 dev_out = __ip_dev_find(net, fl4->saddr, false); 2534 if (!dev_out) 2535 goto out; 2536 2537 /* Special hack: user can direct multicasts 2538 * and limited broadcast via necessary interface 2539 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2540 * This hack is not just for fun, it allows 2541 * vic,vat and friends to work. 2542 * They bind socket to loopback, set ttl to zero 2543 * and expect that it will work. 2544 * From the viewpoint of routing cache they are broken, 2545 * because we are not allowed to build multicast path 2546 * with loopback source addr (look, routing cache 2547 * cannot know, that ttl is zero, so that packet 2548 * will not leave this host and route is valid). 2549 * Luckily, this hack is good workaround. 2550 */ 2551 2552 fl4->flowi4_oif = dev_out->ifindex; 2553 goto make_route; 2554 } 2555 2556 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2557 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2558 if (!__ip_dev_find(net, fl4->saddr, false)) 2559 goto out; 2560 } 2561 } 2562 2563 2564 if (fl4->flowi4_oif) { 2565 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2566 rth = ERR_PTR(-ENODEV); 2567 if (!dev_out) 2568 goto out; 2569 2570 /* RACE: Check return value of inet_select_addr instead. */ 2571 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2572 rth = ERR_PTR(-ENETUNREACH); 2573 goto out; 2574 } 2575 if (ipv4_is_local_multicast(fl4->daddr) || 2576 ipv4_is_lbcast(fl4->daddr) || 2577 fl4->flowi4_proto == IPPROTO_IGMP) { 2578 if (!fl4->saddr) 2579 fl4->saddr = inet_select_addr(dev_out, 0, 2580 RT_SCOPE_LINK); 2581 goto make_route; 2582 } 2583 if (!fl4->saddr) { 2584 if (ipv4_is_multicast(fl4->daddr)) 2585 fl4->saddr = inet_select_addr(dev_out, 0, 2586 fl4->flowi4_scope); 2587 else if (!fl4->daddr) 2588 fl4->saddr = inet_select_addr(dev_out, 0, 2589 RT_SCOPE_HOST); 2590 } 2591 } 2592 2593 if (!fl4->daddr) { 2594 fl4->daddr = fl4->saddr; 2595 if (!fl4->daddr) 2596 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2597 dev_out = net->loopback_dev; 2598 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2599 res->type = RTN_LOCAL; 2600 flags |= RTCF_LOCAL; 2601 goto make_route; 2602 } 2603 2604 err = fib_lookup(net, fl4, res, 0); 2605 if (err) { 2606 res->fi = NULL; 2607 res->table = NULL; 2608 if (fl4->flowi4_oif && 2609 (ipv4_is_multicast(fl4->daddr) || 2610 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2611 /* Apparently, routing tables are wrong. Assume, 2612 * that the destination is on link. 2613 * 2614 * WHY? DW. 2615 * Because we are allowed to send to iface 2616 * even if it has NO routes and NO assigned 2617 * addresses. When oif is specified, routing 2618 * tables are looked up with only one purpose: 2619 * to catch if destination is gatewayed, rather than 2620 * direct. Moreover, if MSG_DONTROUTE is set, 2621 * we send packet, ignoring both routing tables 2622 * and ifaddr state. --ANK 2623 * 2624 * 2625 * We could make it even if oif is unknown, 2626 * likely IPv6, but we do not. 2627 */ 2628 2629 if (fl4->saddr == 0) 2630 fl4->saddr = inet_select_addr(dev_out, 0, 2631 RT_SCOPE_LINK); 2632 res->type = RTN_UNICAST; 2633 goto make_route; 2634 } 2635 rth = ERR_PTR(err); 2636 goto out; 2637 } 2638 2639 if (res->type == RTN_LOCAL) { 2640 if (!fl4->saddr) { 2641 if (res->fi->fib_prefsrc) 2642 fl4->saddr = res->fi->fib_prefsrc; 2643 else 2644 fl4->saddr = fl4->daddr; 2645 } 2646 2647 /* L3 master device is the loopback for that domain */ 2648 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2649 net->loopback_dev; 2650 2651 /* make sure orig_oif points to fib result device even 2652 * though packet rx/tx happens over loopback or l3mdev 2653 */ 2654 orig_oif = FIB_RES_OIF(*res); 2655 2656 fl4->flowi4_oif = dev_out->ifindex; 2657 flags |= RTCF_LOCAL; 2658 goto make_route; 2659 } 2660 2661 fib_select_path(net, res, fl4, skb); 2662 2663 dev_out = FIB_RES_DEV(*res); 2664 2665 make_route: 2666 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2667 2668 out: 2669 return rth; 2670 } 2671 2672 static struct dst_ops ipv4_dst_blackhole_ops = { 2673 .family = AF_INET, 2674 .default_advmss = ipv4_default_advmss, 2675 .neigh_lookup = ipv4_neigh_lookup, 2676 .check = dst_blackhole_check, 2677 .cow_metrics = dst_blackhole_cow_metrics, 2678 .update_pmtu = dst_blackhole_update_pmtu, 2679 .redirect = dst_blackhole_redirect, 2680 .mtu = dst_blackhole_mtu, 2681 }; 2682 2683 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2684 { 2685 struct rtable *ort = (struct rtable *) dst_orig; 2686 struct rtable *rt; 2687 2688 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2689 if (rt) { 2690 struct dst_entry *new = &rt->dst; 2691 2692 new->__use = 1; 2693 new->input = dst_discard; 2694 new->output = dst_discard_out; 2695 2696 new->dev = net->loopback_dev; 2697 if (new->dev) 2698 dev_hold(new->dev); 2699 2700 rt->rt_is_input = ort->rt_is_input; 2701 rt->rt_iif = ort->rt_iif; 2702 rt->rt_pmtu = ort->rt_pmtu; 2703 rt->rt_mtu_locked = ort->rt_mtu_locked; 2704 2705 rt->rt_genid = rt_genid_ipv4(net); 2706 rt->rt_flags = ort->rt_flags; 2707 rt->rt_type = ort->rt_type; 2708 rt->rt_uses_gateway = ort->rt_uses_gateway; 2709 rt->rt_gw_family = ort->rt_gw_family; 2710 if (rt->rt_gw_family == AF_INET) 2711 rt->rt_gw4 = ort->rt_gw4; 2712 else if (rt->rt_gw_family == AF_INET6) 2713 rt->rt_gw6 = ort->rt_gw6; 2714 2715 INIT_LIST_HEAD(&rt->rt_uncached); 2716 } 2717 2718 dst_release(dst_orig); 2719 2720 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2721 } 2722 2723 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2724 const struct sock *sk) 2725 { 2726 struct rtable *rt = __ip_route_output_key(net, flp4); 2727 2728 if (IS_ERR(rt)) 2729 return rt; 2730 2731 if (flp4->flowi4_proto) { 2732 flp4->flowi4_oif = rt->dst.dev->ifindex; 2733 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2734 flowi4_to_flowi(flp4), 2735 sk, 0); 2736 } 2737 2738 return rt; 2739 } 2740 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2741 2742 struct rtable *ip_route_output_tunnel(struct sk_buff *skb, 2743 struct net_device *dev, 2744 struct net *net, __be32 *saddr, 2745 const struct ip_tunnel_info *info, 2746 u8 protocol, bool use_cache) 2747 { 2748 #ifdef CONFIG_DST_CACHE 2749 struct dst_cache *dst_cache; 2750 #endif 2751 struct rtable *rt = NULL; 2752 struct flowi4 fl4; 2753 __u8 tos; 2754 2755 #ifdef CONFIG_DST_CACHE 2756 dst_cache = (struct dst_cache *)&info->dst_cache; 2757 if (use_cache) { 2758 rt = dst_cache_get_ip4(dst_cache, saddr); 2759 if (rt) 2760 return rt; 2761 } 2762 #endif 2763 memset(&fl4, 0, sizeof(fl4)); 2764 fl4.flowi4_mark = skb->mark; 2765 fl4.flowi4_proto = protocol; 2766 fl4.daddr = info->key.u.ipv4.dst; 2767 fl4.saddr = info->key.u.ipv4.src; 2768 tos = info->key.tos; 2769 fl4.flowi4_tos = RT_TOS(tos); 2770 2771 rt = ip_route_output_key(net, &fl4); 2772 if (IS_ERR(rt)) { 2773 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr); 2774 return ERR_PTR(-ENETUNREACH); 2775 } 2776 if (rt->dst.dev == dev) { /* is this necessary? */ 2777 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr); 2778 ip_rt_put(rt); 2779 return ERR_PTR(-ELOOP); 2780 } 2781 #ifdef CONFIG_DST_CACHE 2782 if (use_cache) 2783 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr); 2784 #endif 2785 *saddr = fl4.saddr; 2786 return rt; 2787 } 2788 EXPORT_SYMBOL_GPL(ip_route_output_tunnel); 2789 2790 /* called with rcu_read_lock held */ 2791 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2792 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2793 struct sk_buff *skb, u32 portid, u32 seq, 2794 unsigned int flags) 2795 { 2796 struct rtmsg *r; 2797 struct nlmsghdr *nlh; 2798 unsigned long expires = 0; 2799 u32 error; 2800 u32 metrics[RTAX_MAX]; 2801 2802 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2803 if (!nlh) 2804 return -EMSGSIZE; 2805 2806 r = nlmsg_data(nlh); 2807 r->rtm_family = AF_INET; 2808 r->rtm_dst_len = 32; 2809 r->rtm_src_len = 0; 2810 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2811 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2812 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2813 goto nla_put_failure; 2814 r->rtm_type = rt->rt_type; 2815 r->rtm_scope = RT_SCOPE_UNIVERSE; 2816 r->rtm_protocol = RTPROT_UNSPEC; 2817 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2818 if (rt->rt_flags & RTCF_NOTIFY) 2819 r->rtm_flags |= RTM_F_NOTIFY; 2820 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2821 r->rtm_flags |= RTCF_DOREDIRECT; 2822 2823 if (nla_put_in_addr(skb, RTA_DST, dst)) 2824 goto nla_put_failure; 2825 if (src) { 2826 r->rtm_src_len = 32; 2827 if (nla_put_in_addr(skb, RTA_SRC, src)) 2828 goto nla_put_failure; 2829 } 2830 if (rt->dst.dev && 2831 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2832 goto nla_put_failure; 2833 if (rt->dst.lwtstate && 2834 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 2835 goto nla_put_failure; 2836 #ifdef CONFIG_IP_ROUTE_CLASSID 2837 if (rt->dst.tclassid && 2838 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2839 goto nla_put_failure; 2840 #endif 2841 if (fl4 && !rt_is_input_route(rt) && 2842 fl4->saddr != src) { 2843 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2844 goto nla_put_failure; 2845 } 2846 if (rt->rt_uses_gateway) { 2847 if (rt->rt_gw_family == AF_INET && 2848 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2849 goto nla_put_failure; 2850 } else if (rt->rt_gw_family == AF_INET6) { 2851 int alen = sizeof(struct in6_addr); 2852 struct nlattr *nla; 2853 struct rtvia *via; 2854 2855 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2856 if (!nla) 2857 goto nla_put_failure; 2858 2859 via = nla_data(nla); 2860 via->rtvia_family = AF_INET6; 2861 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2862 } 2863 } 2864 2865 expires = rt->dst.expires; 2866 if (expires) { 2867 unsigned long now = jiffies; 2868 2869 if (time_before(now, expires)) 2870 expires -= now; 2871 else 2872 expires = 0; 2873 } 2874 2875 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2876 if (rt->rt_pmtu && expires) 2877 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2878 if (rt->rt_mtu_locked && expires) 2879 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2880 if (rtnetlink_put_metrics(skb, metrics) < 0) 2881 goto nla_put_failure; 2882 2883 if (fl4) { 2884 if (fl4->flowi4_mark && 2885 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2886 goto nla_put_failure; 2887 2888 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2889 nla_put_u32(skb, RTA_UID, 2890 from_kuid_munged(current_user_ns(), 2891 fl4->flowi4_uid))) 2892 goto nla_put_failure; 2893 2894 if (rt_is_input_route(rt)) { 2895 #ifdef CONFIG_IP_MROUTE 2896 if (ipv4_is_multicast(dst) && 2897 !ipv4_is_local_multicast(dst) && 2898 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2899 int err = ipmr_get_route(net, skb, 2900 fl4->saddr, fl4->daddr, 2901 r, portid); 2902 2903 if (err <= 0) { 2904 if (err == 0) 2905 return 0; 2906 goto nla_put_failure; 2907 } 2908 } else 2909 #endif 2910 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2911 goto nla_put_failure; 2912 } 2913 } 2914 2915 error = rt->dst.error; 2916 2917 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2918 goto nla_put_failure; 2919 2920 nlmsg_end(skb, nlh); 2921 return 0; 2922 2923 nla_put_failure: 2924 nlmsg_cancel(skb, nlh); 2925 return -EMSGSIZE; 2926 } 2927 2928 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2929 struct netlink_callback *cb, u32 table_id, 2930 struct fnhe_hash_bucket *bucket, int genid, 2931 int *fa_index, int fa_start, unsigned int flags) 2932 { 2933 int i; 2934 2935 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2936 struct fib_nh_exception *fnhe; 2937 2938 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2939 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2940 struct rtable *rt; 2941 int err; 2942 2943 if (*fa_index < fa_start) 2944 goto next; 2945 2946 if (fnhe->fnhe_genid != genid) 2947 goto next; 2948 2949 if (fnhe->fnhe_expires && 2950 time_after(jiffies, fnhe->fnhe_expires)) 2951 goto next; 2952 2953 rt = rcu_dereference(fnhe->fnhe_rth_input); 2954 if (!rt) 2955 rt = rcu_dereference(fnhe->fnhe_rth_output); 2956 if (!rt) 2957 goto next; 2958 2959 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2960 table_id, NULL, skb, 2961 NETLINK_CB(cb->skb).portid, 2962 cb->nlh->nlmsg_seq, flags); 2963 if (err) 2964 return err; 2965 next: 2966 (*fa_index)++; 2967 } 2968 } 2969 2970 return 0; 2971 } 2972 2973 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2974 u32 table_id, struct fib_info *fi, 2975 int *fa_index, int fa_start, unsigned int flags) 2976 { 2977 struct net *net = sock_net(cb->skb->sk); 2978 int nhsel, genid = fnhe_genid(net); 2979 2980 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2981 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2982 struct fnhe_hash_bucket *bucket; 2983 int err; 2984 2985 if (nhc->nhc_flags & RTNH_F_DEAD) 2986 continue; 2987 2988 rcu_read_lock(); 2989 bucket = rcu_dereference(nhc->nhc_exceptions); 2990 err = 0; 2991 if (bucket) 2992 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 2993 genid, fa_index, fa_start, 2994 flags); 2995 rcu_read_unlock(); 2996 if (err) 2997 return err; 2998 } 2999 3000 return 0; 3001 } 3002 3003 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3004 u8 ip_proto, __be16 sport, 3005 __be16 dport) 3006 { 3007 struct sk_buff *skb; 3008 struct iphdr *iph; 3009 3010 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3011 if (!skb) 3012 return NULL; 3013 3014 /* Reserve room for dummy headers, this skb can pass 3015 * through good chunk of routing engine. 3016 */ 3017 skb_reset_mac_header(skb); 3018 skb_reset_network_header(skb); 3019 skb->protocol = htons(ETH_P_IP); 3020 iph = skb_put(skb, sizeof(struct iphdr)); 3021 iph->protocol = ip_proto; 3022 iph->saddr = src; 3023 iph->daddr = dst; 3024 iph->version = 0x4; 3025 iph->frag_off = 0; 3026 iph->ihl = 0x5; 3027 skb_set_transport_header(skb, skb->len); 3028 3029 switch (iph->protocol) { 3030 case IPPROTO_UDP: { 3031 struct udphdr *udph; 3032 3033 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3034 udph->source = sport; 3035 udph->dest = dport; 3036 udph->len = sizeof(struct udphdr); 3037 udph->check = 0; 3038 break; 3039 } 3040 case IPPROTO_TCP: { 3041 struct tcphdr *tcph; 3042 3043 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3044 tcph->source = sport; 3045 tcph->dest = dport; 3046 tcph->doff = sizeof(struct tcphdr) / 4; 3047 tcph->rst = 1; 3048 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3049 src, dst, 0); 3050 break; 3051 } 3052 case IPPROTO_ICMP: { 3053 struct icmphdr *icmph; 3054 3055 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3056 icmph->type = ICMP_ECHO; 3057 icmph->code = 0; 3058 } 3059 } 3060 3061 return skb; 3062 } 3063 3064 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3065 const struct nlmsghdr *nlh, 3066 struct nlattr **tb, 3067 struct netlink_ext_ack *extack) 3068 { 3069 struct rtmsg *rtm; 3070 int i, err; 3071 3072 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3073 NL_SET_ERR_MSG(extack, 3074 "ipv4: Invalid header for route get request"); 3075 return -EINVAL; 3076 } 3077 3078 if (!netlink_strict_get_check(skb)) 3079 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3080 rtm_ipv4_policy, extack); 3081 3082 rtm = nlmsg_data(nlh); 3083 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3084 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3085 rtm->rtm_table || rtm->rtm_protocol || 3086 rtm->rtm_scope || rtm->rtm_type) { 3087 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3088 return -EINVAL; 3089 } 3090 3091 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3092 RTM_F_LOOKUP_TABLE | 3093 RTM_F_FIB_MATCH)) { 3094 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3095 return -EINVAL; 3096 } 3097 3098 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3099 rtm_ipv4_policy, extack); 3100 if (err) 3101 return err; 3102 3103 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3104 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3105 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3106 return -EINVAL; 3107 } 3108 3109 for (i = 0; i <= RTA_MAX; i++) { 3110 if (!tb[i]) 3111 continue; 3112 3113 switch (i) { 3114 case RTA_IIF: 3115 case RTA_OIF: 3116 case RTA_SRC: 3117 case RTA_DST: 3118 case RTA_IP_PROTO: 3119 case RTA_SPORT: 3120 case RTA_DPORT: 3121 case RTA_MARK: 3122 case RTA_UID: 3123 break; 3124 default: 3125 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3126 return -EINVAL; 3127 } 3128 } 3129 3130 return 0; 3131 } 3132 3133 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3134 struct netlink_ext_ack *extack) 3135 { 3136 struct net *net = sock_net(in_skb->sk); 3137 struct nlattr *tb[RTA_MAX+1]; 3138 u32 table_id = RT_TABLE_MAIN; 3139 __be16 sport = 0, dport = 0; 3140 struct fib_result res = {}; 3141 u8 ip_proto = IPPROTO_UDP; 3142 struct rtable *rt = NULL; 3143 struct sk_buff *skb; 3144 struct rtmsg *rtm; 3145 struct flowi4 fl4 = {}; 3146 __be32 dst = 0; 3147 __be32 src = 0; 3148 kuid_t uid; 3149 u32 iif; 3150 int err; 3151 int mark; 3152 3153 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3154 if (err < 0) 3155 return err; 3156 3157 rtm = nlmsg_data(nlh); 3158 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3159 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3160 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3161 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3162 if (tb[RTA_UID]) 3163 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3164 else 3165 uid = (iif ? INVALID_UID : current_uid()); 3166 3167 if (tb[RTA_IP_PROTO]) { 3168 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3169 &ip_proto, AF_INET, extack); 3170 if (err) 3171 return err; 3172 } 3173 3174 if (tb[RTA_SPORT]) 3175 sport = nla_get_be16(tb[RTA_SPORT]); 3176 3177 if (tb[RTA_DPORT]) 3178 dport = nla_get_be16(tb[RTA_DPORT]); 3179 3180 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3181 if (!skb) 3182 return -ENOBUFS; 3183 3184 fl4.daddr = dst; 3185 fl4.saddr = src; 3186 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK; 3187 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3188 fl4.flowi4_mark = mark; 3189 fl4.flowi4_uid = uid; 3190 if (sport) 3191 fl4.fl4_sport = sport; 3192 if (dport) 3193 fl4.fl4_dport = dport; 3194 fl4.flowi4_proto = ip_proto; 3195 3196 rcu_read_lock(); 3197 3198 if (iif) { 3199 struct net_device *dev; 3200 3201 dev = dev_get_by_index_rcu(net, iif); 3202 if (!dev) { 3203 err = -ENODEV; 3204 goto errout_rcu; 3205 } 3206 3207 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3208 skb->dev = dev; 3209 skb->mark = mark; 3210 err = ip_route_input_rcu(skb, dst, src, 3211 rtm->rtm_tos & IPTOS_RT_MASK, dev, 3212 &res); 3213 3214 rt = skb_rtable(skb); 3215 if (err == 0 && rt->dst.error) 3216 err = -rt->dst.error; 3217 } else { 3218 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3219 skb->dev = net->loopback_dev; 3220 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3221 err = 0; 3222 if (IS_ERR(rt)) 3223 err = PTR_ERR(rt); 3224 else 3225 skb_dst_set(skb, &rt->dst); 3226 } 3227 3228 if (err) 3229 goto errout_rcu; 3230 3231 if (rtm->rtm_flags & RTM_F_NOTIFY) 3232 rt->rt_flags |= RTCF_NOTIFY; 3233 3234 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3235 table_id = res.table ? res.table->tb_id : 0; 3236 3237 /* reset skb for netlink reply msg */ 3238 skb_trim(skb, 0); 3239 skb_reset_network_header(skb); 3240 skb_reset_transport_header(skb); 3241 skb_reset_mac_header(skb); 3242 3243 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3244 struct fib_rt_info fri; 3245 3246 if (!res.fi) { 3247 err = fib_props[res.type].error; 3248 if (!err) 3249 err = -EHOSTUNREACH; 3250 goto errout_rcu; 3251 } 3252 fri.fi = res.fi; 3253 fri.tb_id = table_id; 3254 fri.dst = res.prefix; 3255 fri.dst_len = res.prefixlen; 3256 fri.tos = fl4.flowi4_tos; 3257 fri.type = rt->rt_type; 3258 fri.offload = 0; 3259 fri.trap = 0; 3260 fri.offload_failed = 0; 3261 if (res.fa_head) { 3262 struct fib_alias *fa; 3263 3264 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3265 u8 slen = 32 - fri.dst_len; 3266 3267 if (fa->fa_slen == slen && 3268 fa->tb_id == fri.tb_id && 3269 fa->fa_tos == fri.tos && 3270 fa->fa_info == res.fi && 3271 fa->fa_type == fri.type) { 3272 fri.offload = fa->offload; 3273 fri.trap = fa->trap; 3274 break; 3275 } 3276 } 3277 } 3278 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3279 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3280 } else { 3281 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3282 NETLINK_CB(in_skb).portid, 3283 nlh->nlmsg_seq, 0); 3284 } 3285 if (err < 0) 3286 goto errout_rcu; 3287 3288 rcu_read_unlock(); 3289 3290 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3291 3292 errout_free: 3293 return err; 3294 errout_rcu: 3295 rcu_read_unlock(); 3296 kfree_skb(skb); 3297 goto errout_free; 3298 } 3299 3300 void ip_rt_multicast_event(struct in_device *in_dev) 3301 { 3302 rt_cache_flush(dev_net(in_dev->dev)); 3303 } 3304 3305 #ifdef CONFIG_SYSCTL 3306 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3307 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3308 static int ip_rt_gc_elasticity __read_mostly = 8; 3309 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3310 3311 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3312 void *buffer, size_t *lenp, loff_t *ppos) 3313 { 3314 struct net *net = (struct net *)__ctl->extra1; 3315 3316 if (write) { 3317 rt_cache_flush(net); 3318 fnhe_genid_bump(net); 3319 return 0; 3320 } 3321 3322 return -EINVAL; 3323 } 3324 3325 static struct ctl_table ipv4_route_table[] = { 3326 { 3327 .procname = "gc_thresh", 3328 .data = &ipv4_dst_ops.gc_thresh, 3329 .maxlen = sizeof(int), 3330 .mode = 0644, 3331 .proc_handler = proc_dointvec, 3332 }, 3333 { 3334 .procname = "max_size", 3335 .data = &ip_rt_max_size, 3336 .maxlen = sizeof(int), 3337 .mode = 0644, 3338 .proc_handler = proc_dointvec, 3339 }, 3340 { 3341 /* Deprecated. Use gc_min_interval_ms */ 3342 3343 .procname = "gc_min_interval", 3344 .data = &ip_rt_gc_min_interval, 3345 .maxlen = sizeof(int), 3346 .mode = 0644, 3347 .proc_handler = proc_dointvec_jiffies, 3348 }, 3349 { 3350 .procname = "gc_min_interval_ms", 3351 .data = &ip_rt_gc_min_interval, 3352 .maxlen = sizeof(int), 3353 .mode = 0644, 3354 .proc_handler = proc_dointvec_ms_jiffies, 3355 }, 3356 { 3357 .procname = "gc_timeout", 3358 .data = &ip_rt_gc_timeout, 3359 .maxlen = sizeof(int), 3360 .mode = 0644, 3361 .proc_handler = proc_dointvec_jiffies, 3362 }, 3363 { 3364 .procname = "gc_interval", 3365 .data = &ip_rt_gc_interval, 3366 .maxlen = sizeof(int), 3367 .mode = 0644, 3368 .proc_handler = proc_dointvec_jiffies, 3369 }, 3370 { 3371 .procname = "redirect_load", 3372 .data = &ip_rt_redirect_load, 3373 .maxlen = sizeof(int), 3374 .mode = 0644, 3375 .proc_handler = proc_dointvec, 3376 }, 3377 { 3378 .procname = "redirect_number", 3379 .data = &ip_rt_redirect_number, 3380 .maxlen = sizeof(int), 3381 .mode = 0644, 3382 .proc_handler = proc_dointvec, 3383 }, 3384 { 3385 .procname = "redirect_silence", 3386 .data = &ip_rt_redirect_silence, 3387 .maxlen = sizeof(int), 3388 .mode = 0644, 3389 .proc_handler = proc_dointvec, 3390 }, 3391 { 3392 .procname = "error_cost", 3393 .data = &ip_rt_error_cost, 3394 .maxlen = sizeof(int), 3395 .mode = 0644, 3396 .proc_handler = proc_dointvec, 3397 }, 3398 { 3399 .procname = "error_burst", 3400 .data = &ip_rt_error_burst, 3401 .maxlen = sizeof(int), 3402 .mode = 0644, 3403 .proc_handler = proc_dointvec, 3404 }, 3405 { 3406 .procname = "gc_elasticity", 3407 .data = &ip_rt_gc_elasticity, 3408 .maxlen = sizeof(int), 3409 .mode = 0644, 3410 .proc_handler = proc_dointvec, 3411 }, 3412 { 3413 .procname = "mtu_expires", 3414 .data = &ip_rt_mtu_expires, 3415 .maxlen = sizeof(int), 3416 .mode = 0644, 3417 .proc_handler = proc_dointvec_jiffies, 3418 }, 3419 { 3420 .procname = "min_pmtu", 3421 .data = &ip_rt_min_pmtu, 3422 .maxlen = sizeof(int), 3423 .mode = 0644, 3424 .proc_handler = proc_dointvec_minmax, 3425 .extra1 = &ip_min_valid_pmtu, 3426 }, 3427 { 3428 .procname = "min_adv_mss", 3429 .data = &ip_rt_min_advmss, 3430 .maxlen = sizeof(int), 3431 .mode = 0644, 3432 .proc_handler = proc_dointvec, 3433 }, 3434 { } 3435 }; 3436 3437 static const char ipv4_route_flush_procname[] = "flush"; 3438 3439 static struct ctl_table ipv4_route_flush_table[] = { 3440 { 3441 .procname = ipv4_route_flush_procname, 3442 .maxlen = sizeof(int), 3443 .mode = 0200, 3444 .proc_handler = ipv4_sysctl_rtcache_flush, 3445 }, 3446 { }, 3447 }; 3448 3449 static __net_init int sysctl_route_net_init(struct net *net) 3450 { 3451 struct ctl_table *tbl; 3452 3453 tbl = ipv4_route_flush_table; 3454 if (!net_eq(net, &init_net)) { 3455 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3456 if (!tbl) 3457 goto err_dup; 3458 3459 /* Don't export non-whitelisted sysctls to unprivileged users */ 3460 if (net->user_ns != &init_user_ns) { 3461 if (tbl[0].procname != ipv4_route_flush_procname) 3462 tbl[0].procname = NULL; 3463 } 3464 } 3465 tbl[0].extra1 = net; 3466 3467 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3468 if (!net->ipv4.route_hdr) 3469 goto err_reg; 3470 return 0; 3471 3472 err_reg: 3473 if (tbl != ipv4_route_flush_table) 3474 kfree(tbl); 3475 err_dup: 3476 return -ENOMEM; 3477 } 3478 3479 static __net_exit void sysctl_route_net_exit(struct net *net) 3480 { 3481 struct ctl_table *tbl; 3482 3483 tbl = net->ipv4.route_hdr->ctl_table_arg; 3484 unregister_net_sysctl_table(net->ipv4.route_hdr); 3485 BUG_ON(tbl == ipv4_route_flush_table); 3486 kfree(tbl); 3487 } 3488 3489 static __net_initdata struct pernet_operations sysctl_route_ops = { 3490 .init = sysctl_route_net_init, 3491 .exit = sysctl_route_net_exit, 3492 }; 3493 #endif 3494 3495 static __net_init int rt_genid_init(struct net *net) 3496 { 3497 atomic_set(&net->ipv4.rt_genid, 0); 3498 atomic_set(&net->fnhe_genid, 0); 3499 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3500 return 0; 3501 } 3502 3503 static __net_initdata struct pernet_operations rt_genid_ops = { 3504 .init = rt_genid_init, 3505 }; 3506 3507 static int __net_init ipv4_inetpeer_init(struct net *net) 3508 { 3509 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3510 3511 if (!bp) 3512 return -ENOMEM; 3513 inet_peer_base_init(bp); 3514 net->ipv4.peers = bp; 3515 return 0; 3516 } 3517 3518 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3519 { 3520 struct inet_peer_base *bp = net->ipv4.peers; 3521 3522 net->ipv4.peers = NULL; 3523 inetpeer_invalidate_tree(bp); 3524 kfree(bp); 3525 } 3526 3527 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3528 .init = ipv4_inetpeer_init, 3529 .exit = ipv4_inetpeer_exit, 3530 }; 3531 3532 #ifdef CONFIG_IP_ROUTE_CLASSID 3533 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3534 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3535 3536 int __init ip_rt_init(void) 3537 { 3538 void *idents_hash; 3539 int cpu; 3540 3541 /* For modern hosts, this will use 2 MB of memory */ 3542 idents_hash = alloc_large_system_hash("IP idents", 3543 sizeof(*ip_idents) + sizeof(*ip_tstamps), 3544 0, 3545 16, /* one bucket per 64 KB */ 3546 HASH_ZERO, 3547 NULL, 3548 &ip_idents_mask, 3549 2048, 3550 256*1024); 3551 3552 ip_idents = idents_hash; 3553 3554 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents)); 3555 3556 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents); 3557 3558 for_each_possible_cpu(cpu) { 3559 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3560 3561 INIT_LIST_HEAD(&ul->head); 3562 spin_lock_init(&ul->lock); 3563 } 3564 #ifdef CONFIG_IP_ROUTE_CLASSID 3565 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3566 if (!ip_rt_acct) 3567 panic("IP: failed to allocate ip_rt_acct\n"); 3568 #endif 3569 3570 ipv4_dst_ops.kmem_cachep = 3571 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3572 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3573 3574 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3575 3576 if (dst_entries_init(&ipv4_dst_ops) < 0) 3577 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3578 3579 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3580 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3581 3582 ipv4_dst_ops.gc_thresh = ~0; 3583 ip_rt_max_size = INT_MAX; 3584 3585 devinet_init(); 3586 ip_fib_init(); 3587 3588 if (ip_rt_proc_init()) 3589 pr_err("Unable to create route proc files\n"); 3590 #ifdef CONFIG_XFRM 3591 xfrm_init(); 3592 xfrm4_init(); 3593 #endif 3594 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3595 RTNL_FLAG_DOIT_UNLOCKED); 3596 3597 #ifdef CONFIG_SYSCTL 3598 register_pernet_subsys(&sysctl_route_ops); 3599 #endif 3600 register_pernet_subsys(&rt_genid_ops); 3601 register_pernet_subsys(&ipv4_inetpeer_ops); 3602 return 0; 3603 } 3604 3605 #ifdef CONFIG_SYSCTL 3606 /* 3607 * We really need to sanitize the damn ipv4 init order, then all 3608 * this nonsense will go away. 3609 */ 3610 void __init ip_static_sysctl_init(void) 3611 { 3612 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3613 } 3614 #endif 3615