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 /* get device for dst_alloc with local routes */ 2060 static struct net_device *ip_rt_get_dev(struct net *net, 2061 const struct fib_result *res) 2062 { 2063 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL; 2064 struct net_device *dev = NULL; 2065 2066 if (nhc) 2067 dev = l3mdev_master_dev_rcu(nhc->nhc_dev); 2068 2069 return dev ? : net->loopback_dev; 2070 } 2071 2072 /* 2073 * NOTE. We drop all the packets that has local source 2074 * addresses, because every properly looped back packet 2075 * must have correct destination already attached by output routine. 2076 * Changes in the enforced policies must be applied also to 2077 * ip_route_use_hint(). 2078 * 2079 * Such approach solves two big problems: 2080 * 1. Not simplex devices are handled properly. 2081 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2082 * called with rcu_read_lock() 2083 */ 2084 2085 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2086 u8 tos, struct net_device *dev, 2087 struct fib_result *res) 2088 { 2089 struct in_device *in_dev = __in_dev_get_rcu(dev); 2090 struct flow_keys *flkeys = NULL, _flkeys; 2091 struct net *net = dev_net(dev); 2092 struct ip_tunnel_info *tun_info; 2093 int err = -EINVAL; 2094 unsigned int flags = 0; 2095 u32 itag = 0; 2096 struct rtable *rth; 2097 struct flowi4 fl4; 2098 bool do_cache = true; 2099 2100 /* IP on this device is disabled. */ 2101 2102 if (!in_dev) 2103 goto out; 2104 2105 /* Check for the most weird martians, which can be not detected 2106 * by fib_lookup. 2107 */ 2108 2109 tun_info = skb_tunnel_info(skb); 2110 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2111 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2112 else 2113 fl4.flowi4_tun_key.tun_id = 0; 2114 skb_dst_drop(skb); 2115 2116 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2117 goto martian_source; 2118 2119 res->fi = NULL; 2120 res->table = NULL; 2121 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2122 goto brd_input; 2123 2124 /* Accept zero addresses only to limited broadcast; 2125 * I even do not know to fix it or not. Waiting for complains :-) 2126 */ 2127 if (ipv4_is_zeronet(saddr)) 2128 goto martian_source; 2129 2130 if (ipv4_is_zeronet(daddr)) 2131 goto martian_destination; 2132 2133 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2134 * and call it once if daddr or/and saddr are loopback addresses 2135 */ 2136 if (ipv4_is_loopback(daddr)) { 2137 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2138 goto martian_destination; 2139 } else if (ipv4_is_loopback(saddr)) { 2140 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2141 goto martian_source; 2142 } 2143 2144 /* 2145 * Now we are ready to route packet. 2146 */ 2147 fl4.flowi4_oif = 0; 2148 fl4.flowi4_iif = dev->ifindex; 2149 fl4.flowi4_mark = skb->mark; 2150 fl4.flowi4_tos = tos; 2151 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2152 fl4.flowi4_flags = 0; 2153 fl4.daddr = daddr; 2154 fl4.saddr = saddr; 2155 fl4.flowi4_uid = sock_net_uid(net, NULL); 2156 fl4.flowi4_multipath_hash = 0; 2157 2158 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2159 flkeys = &_flkeys; 2160 } else { 2161 fl4.flowi4_proto = 0; 2162 fl4.fl4_sport = 0; 2163 fl4.fl4_dport = 0; 2164 } 2165 2166 err = fib_lookup(net, &fl4, res, 0); 2167 if (err != 0) { 2168 if (!IN_DEV_FORWARD(in_dev)) 2169 err = -EHOSTUNREACH; 2170 goto no_route; 2171 } 2172 2173 if (res->type == RTN_BROADCAST) { 2174 if (IN_DEV_BFORWARD(in_dev)) 2175 goto make_route; 2176 /* not do cache if bc_forwarding is enabled */ 2177 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2178 do_cache = false; 2179 goto brd_input; 2180 } 2181 2182 if (res->type == RTN_LOCAL) { 2183 err = fib_validate_source(skb, saddr, daddr, tos, 2184 0, dev, in_dev, &itag); 2185 if (err < 0) 2186 goto martian_source; 2187 goto local_input; 2188 } 2189 2190 if (!IN_DEV_FORWARD(in_dev)) { 2191 err = -EHOSTUNREACH; 2192 goto no_route; 2193 } 2194 if (res->type != RTN_UNICAST) 2195 goto martian_destination; 2196 2197 make_route: 2198 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2199 out: return err; 2200 2201 brd_input: 2202 if (skb->protocol != htons(ETH_P_IP)) 2203 goto e_inval; 2204 2205 if (!ipv4_is_zeronet(saddr)) { 2206 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2207 in_dev, &itag); 2208 if (err < 0) 2209 goto martian_source; 2210 } 2211 flags |= RTCF_BROADCAST; 2212 res->type = RTN_BROADCAST; 2213 RT_CACHE_STAT_INC(in_brd); 2214 2215 local_input: 2216 do_cache &= res->fi && !itag; 2217 if (do_cache) { 2218 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2219 2220 rth = rcu_dereference(nhc->nhc_rth_input); 2221 if (rt_cache_valid(rth)) { 2222 skb_dst_set_noref(skb, &rth->dst); 2223 err = 0; 2224 goto out; 2225 } 2226 } 2227 2228 rth = rt_dst_alloc(ip_rt_get_dev(net, res), 2229 flags | RTCF_LOCAL, res->type, 2230 IN_DEV_ORCONF(in_dev, NOPOLICY), false); 2231 if (!rth) 2232 goto e_nobufs; 2233 2234 rth->dst.output= ip_rt_bug; 2235 #ifdef CONFIG_IP_ROUTE_CLASSID 2236 rth->dst.tclassid = itag; 2237 #endif 2238 rth->rt_is_input = 1; 2239 2240 RT_CACHE_STAT_INC(in_slow_tot); 2241 if (res->type == RTN_UNREACHABLE) { 2242 rth->dst.input= ip_error; 2243 rth->dst.error= -err; 2244 rth->rt_flags &= ~RTCF_LOCAL; 2245 } 2246 2247 if (do_cache) { 2248 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2249 2250 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2251 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2252 WARN_ON(rth->dst.input == lwtunnel_input); 2253 rth->dst.lwtstate->orig_input = rth->dst.input; 2254 rth->dst.input = lwtunnel_input; 2255 } 2256 2257 if (unlikely(!rt_cache_route(nhc, rth))) 2258 rt_add_uncached_list(rth); 2259 } 2260 skb_dst_set(skb, &rth->dst); 2261 err = 0; 2262 goto out; 2263 2264 no_route: 2265 RT_CACHE_STAT_INC(in_no_route); 2266 res->type = RTN_UNREACHABLE; 2267 res->fi = NULL; 2268 res->table = NULL; 2269 goto local_input; 2270 2271 /* 2272 * Do not cache martian addresses: they should be logged (RFC1812) 2273 */ 2274 martian_destination: 2275 RT_CACHE_STAT_INC(in_martian_dst); 2276 #ifdef CONFIG_IP_ROUTE_VERBOSE 2277 if (IN_DEV_LOG_MARTIANS(in_dev)) 2278 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2279 &daddr, &saddr, dev->name); 2280 #endif 2281 2282 e_inval: 2283 err = -EINVAL; 2284 goto out; 2285 2286 e_nobufs: 2287 err = -ENOBUFS; 2288 goto out; 2289 2290 martian_source: 2291 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2292 goto out; 2293 } 2294 2295 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2296 u8 tos, struct net_device *dev) 2297 { 2298 struct fib_result res; 2299 int err; 2300 2301 tos &= IPTOS_RT_MASK; 2302 rcu_read_lock(); 2303 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2304 rcu_read_unlock(); 2305 2306 return err; 2307 } 2308 EXPORT_SYMBOL(ip_route_input_noref); 2309 2310 /* called with rcu_read_lock held */ 2311 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2312 u8 tos, struct net_device *dev, struct fib_result *res) 2313 { 2314 /* Multicast recognition logic is moved from route cache to here. 2315 * The problem was that too many Ethernet cards have broken/missing 2316 * hardware multicast filters :-( As result the host on multicasting 2317 * network acquires a lot of useless route cache entries, sort of 2318 * SDR messages from all the world. Now we try to get rid of them. 2319 * Really, provided software IP multicast filter is organized 2320 * reasonably (at least, hashed), it does not result in a slowdown 2321 * comparing with route cache reject entries. 2322 * Note, that multicast routers are not affected, because 2323 * route cache entry is created eventually. 2324 */ 2325 if (ipv4_is_multicast(daddr)) { 2326 struct in_device *in_dev = __in_dev_get_rcu(dev); 2327 int our = 0; 2328 int err = -EINVAL; 2329 2330 if (!in_dev) 2331 return err; 2332 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2333 ip_hdr(skb)->protocol); 2334 2335 /* check l3 master if no match yet */ 2336 if (!our && netif_is_l3_slave(dev)) { 2337 struct in_device *l3_in_dev; 2338 2339 l3_in_dev = __in_dev_get_rcu(skb->dev); 2340 if (l3_in_dev) 2341 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2342 ip_hdr(skb)->protocol); 2343 } 2344 2345 if (our 2346 #ifdef CONFIG_IP_MROUTE 2347 || 2348 (!ipv4_is_local_multicast(daddr) && 2349 IN_DEV_MFORWARD(in_dev)) 2350 #endif 2351 ) { 2352 err = ip_route_input_mc(skb, daddr, saddr, 2353 tos, dev, our); 2354 } 2355 return err; 2356 } 2357 2358 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2359 } 2360 2361 /* called with rcu_read_lock() */ 2362 static struct rtable *__mkroute_output(const struct fib_result *res, 2363 const struct flowi4 *fl4, int orig_oif, 2364 struct net_device *dev_out, 2365 unsigned int flags) 2366 { 2367 struct fib_info *fi = res->fi; 2368 struct fib_nh_exception *fnhe; 2369 struct in_device *in_dev; 2370 u16 type = res->type; 2371 struct rtable *rth; 2372 bool do_cache; 2373 2374 in_dev = __in_dev_get_rcu(dev_out); 2375 if (!in_dev) 2376 return ERR_PTR(-EINVAL); 2377 2378 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2379 if (ipv4_is_loopback(fl4->saddr) && 2380 !(dev_out->flags & IFF_LOOPBACK) && 2381 !netif_is_l3_master(dev_out)) 2382 return ERR_PTR(-EINVAL); 2383 2384 if (ipv4_is_lbcast(fl4->daddr)) 2385 type = RTN_BROADCAST; 2386 else if (ipv4_is_multicast(fl4->daddr)) 2387 type = RTN_MULTICAST; 2388 else if (ipv4_is_zeronet(fl4->daddr)) 2389 return ERR_PTR(-EINVAL); 2390 2391 if (dev_out->flags & IFF_LOOPBACK) 2392 flags |= RTCF_LOCAL; 2393 2394 do_cache = true; 2395 if (type == RTN_BROADCAST) { 2396 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2397 fi = NULL; 2398 } else if (type == RTN_MULTICAST) { 2399 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2400 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2401 fl4->flowi4_proto)) 2402 flags &= ~RTCF_LOCAL; 2403 else 2404 do_cache = false; 2405 /* If multicast route do not exist use 2406 * default one, but do not gateway in this case. 2407 * Yes, it is hack. 2408 */ 2409 if (fi && res->prefixlen < 4) 2410 fi = NULL; 2411 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2412 (orig_oif != dev_out->ifindex)) { 2413 /* For local routes that require a particular output interface 2414 * we do not want to cache the result. Caching the result 2415 * causes incorrect behaviour when there are multiple source 2416 * addresses on the interface, the end result being that if the 2417 * intended recipient is waiting on that interface for the 2418 * packet he won't receive it because it will be delivered on 2419 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2420 * be set to the loopback interface as well. 2421 */ 2422 do_cache = false; 2423 } 2424 2425 fnhe = NULL; 2426 do_cache &= fi != NULL; 2427 if (fi) { 2428 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2429 struct rtable __rcu **prth; 2430 2431 fnhe = find_exception(nhc, fl4->daddr); 2432 if (!do_cache) 2433 goto add; 2434 if (fnhe) { 2435 prth = &fnhe->fnhe_rth_output; 2436 } else { 2437 if (unlikely(fl4->flowi4_flags & 2438 FLOWI_FLAG_KNOWN_NH && 2439 !(nhc->nhc_gw_family && 2440 nhc->nhc_scope == RT_SCOPE_LINK))) { 2441 do_cache = false; 2442 goto add; 2443 } 2444 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2445 } 2446 rth = rcu_dereference(*prth); 2447 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2448 return rth; 2449 } 2450 2451 add: 2452 rth = rt_dst_alloc(dev_out, flags, type, 2453 IN_DEV_ORCONF(in_dev, NOPOLICY), 2454 IN_DEV_ORCONF(in_dev, NOXFRM)); 2455 if (!rth) 2456 return ERR_PTR(-ENOBUFS); 2457 2458 rth->rt_iif = orig_oif; 2459 2460 RT_CACHE_STAT_INC(out_slow_tot); 2461 2462 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2463 if (flags & RTCF_LOCAL && 2464 !(dev_out->flags & IFF_LOOPBACK)) { 2465 rth->dst.output = ip_mc_output; 2466 RT_CACHE_STAT_INC(out_slow_mc); 2467 } 2468 #ifdef CONFIG_IP_MROUTE 2469 if (type == RTN_MULTICAST) { 2470 if (IN_DEV_MFORWARD(in_dev) && 2471 !ipv4_is_local_multicast(fl4->daddr)) { 2472 rth->dst.input = ip_mr_input; 2473 rth->dst.output = ip_mc_output; 2474 } 2475 } 2476 #endif 2477 } 2478 2479 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2480 lwtunnel_set_redirect(&rth->dst); 2481 2482 return rth; 2483 } 2484 2485 /* 2486 * Major route resolver routine. 2487 */ 2488 2489 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2490 const struct sk_buff *skb) 2491 { 2492 __u8 tos = RT_FL_TOS(fl4); 2493 struct fib_result res = { 2494 .type = RTN_UNSPEC, 2495 .fi = NULL, 2496 .table = NULL, 2497 .tclassid = 0, 2498 }; 2499 struct rtable *rth; 2500 2501 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2502 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2503 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2504 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2505 2506 rcu_read_lock(); 2507 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2508 rcu_read_unlock(); 2509 2510 return rth; 2511 } 2512 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2513 2514 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2515 struct fib_result *res, 2516 const struct sk_buff *skb) 2517 { 2518 struct net_device *dev_out = NULL; 2519 int orig_oif = fl4->flowi4_oif; 2520 unsigned int flags = 0; 2521 struct rtable *rth; 2522 int err; 2523 2524 if (fl4->saddr) { 2525 if (ipv4_is_multicast(fl4->saddr) || 2526 ipv4_is_lbcast(fl4->saddr) || 2527 ipv4_is_zeronet(fl4->saddr)) { 2528 rth = ERR_PTR(-EINVAL); 2529 goto out; 2530 } 2531 2532 rth = ERR_PTR(-ENETUNREACH); 2533 2534 /* I removed check for oif == dev_out->oif here. 2535 * It was wrong for two reasons: 2536 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2537 * is assigned to multiple interfaces. 2538 * 2. Moreover, we are allowed to send packets with saddr 2539 * of another iface. --ANK 2540 */ 2541 2542 if (fl4->flowi4_oif == 0 && 2543 (ipv4_is_multicast(fl4->daddr) || 2544 ipv4_is_lbcast(fl4->daddr))) { 2545 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2546 dev_out = __ip_dev_find(net, fl4->saddr, false); 2547 if (!dev_out) 2548 goto out; 2549 2550 /* Special hack: user can direct multicasts 2551 * and limited broadcast via necessary interface 2552 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2553 * This hack is not just for fun, it allows 2554 * vic,vat and friends to work. 2555 * They bind socket to loopback, set ttl to zero 2556 * and expect that it will work. 2557 * From the viewpoint of routing cache they are broken, 2558 * because we are not allowed to build multicast path 2559 * with loopback source addr (look, routing cache 2560 * cannot know, that ttl is zero, so that packet 2561 * will not leave this host and route is valid). 2562 * Luckily, this hack is good workaround. 2563 */ 2564 2565 fl4->flowi4_oif = dev_out->ifindex; 2566 goto make_route; 2567 } 2568 2569 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2570 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2571 if (!__ip_dev_find(net, fl4->saddr, false)) 2572 goto out; 2573 } 2574 } 2575 2576 2577 if (fl4->flowi4_oif) { 2578 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2579 rth = ERR_PTR(-ENODEV); 2580 if (!dev_out) 2581 goto out; 2582 2583 /* RACE: Check return value of inet_select_addr instead. */ 2584 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2585 rth = ERR_PTR(-ENETUNREACH); 2586 goto out; 2587 } 2588 if (ipv4_is_local_multicast(fl4->daddr) || 2589 ipv4_is_lbcast(fl4->daddr) || 2590 fl4->flowi4_proto == IPPROTO_IGMP) { 2591 if (!fl4->saddr) 2592 fl4->saddr = inet_select_addr(dev_out, 0, 2593 RT_SCOPE_LINK); 2594 goto make_route; 2595 } 2596 if (!fl4->saddr) { 2597 if (ipv4_is_multicast(fl4->daddr)) 2598 fl4->saddr = inet_select_addr(dev_out, 0, 2599 fl4->flowi4_scope); 2600 else if (!fl4->daddr) 2601 fl4->saddr = inet_select_addr(dev_out, 0, 2602 RT_SCOPE_HOST); 2603 } 2604 } 2605 2606 if (!fl4->daddr) { 2607 fl4->daddr = fl4->saddr; 2608 if (!fl4->daddr) 2609 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2610 dev_out = net->loopback_dev; 2611 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2612 res->type = RTN_LOCAL; 2613 flags |= RTCF_LOCAL; 2614 goto make_route; 2615 } 2616 2617 err = fib_lookup(net, fl4, res, 0); 2618 if (err) { 2619 res->fi = NULL; 2620 res->table = NULL; 2621 if (fl4->flowi4_oif && 2622 (ipv4_is_multicast(fl4->daddr) || 2623 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2624 /* Apparently, routing tables are wrong. Assume, 2625 * that the destination is on link. 2626 * 2627 * WHY? DW. 2628 * Because we are allowed to send to iface 2629 * even if it has NO routes and NO assigned 2630 * addresses. When oif is specified, routing 2631 * tables are looked up with only one purpose: 2632 * to catch if destination is gatewayed, rather than 2633 * direct. Moreover, if MSG_DONTROUTE is set, 2634 * we send packet, ignoring both routing tables 2635 * and ifaddr state. --ANK 2636 * 2637 * 2638 * We could make it even if oif is unknown, 2639 * likely IPv6, but we do not. 2640 */ 2641 2642 if (fl4->saddr == 0) 2643 fl4->saddr = inet_select_addr(dev_out, 0, 2644 RT_SCOPE_LINK); 2645 res->type = RTN_UNICAST; 2646 goto make_route; 2647 } 2648 rth = ERR_PTR(err); 2649 goto out; 2650 } 2651 2652 if (res->type == RTN_LOCAL) { 2653 if (!fl4->saddr) { 2654 if (res->fi->fib_prefsrc) 2655 fl4->saddr = res->fi->fib_prefsrc; 2656 else 2657 fl4->saddr = fl4->daddr; 2658 } 2659 2660 /* L3 master device is the loopback for that domain */ 2661 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2662 net->loopback_dev; 2663 2664 /* make sure orig_oif points to fib result device even 2665 * though packet rx/tx happens over loopback or l3mdev 2666 */ 2667 orig_oif = FIB_RES_OIF(*res); 2668 2669 fl4->flowi4_oif = dev_out->ifindex; 2670 flags |= RTCF_LOCAL; 2671 goto make_route; 2672 } 2673 2674 fib_select_path(net, res, fl4, skb); 2675 2676 dev_out = FIB_RES_DEV(*res); 2677 2678 make_route: 2679 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2680 2681 out: 2682 return rth; 2683 } 2684 2685 static struct dst_ops ipv4_dst_blackhole_ops = { 2686 .family = AF_INET, 2687 .default_advmss = ipv4_default_advmss, 2688 .neigh_lookup = ipv4_neigh_lookup, 2689 .check = dst_blackhole_check, 2690 .cow_metrics = dst_blackhole_cow_metrics, 2691 .update_pmtu = dst_blackhole_update_pmtu, 2692 .redirect = dst_blackhole_redirect, 2693 .mtu = dst_blackhole_mtu, 2694 }; 2695 2696 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2697 { 2698 struct rtable *ort = (struct rtable *) dst_orig; 2699 struct rtable *rt; 2700 2701 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2702 if (rt) { 2703 struct dst_entry *new = &rt->dst; 2704 2705 new->__use = 1; 2706 new->input = dst_discard; 2707 new->output = dst_discard_out; 2708 2709 new->dev = net->loopback_dev; 2710 if (new->dev) 2711 dev_hold(new->dev); 2712 2713 rt->rt_is_input = ort->rt_is_input; 2714 rt->rt_iif = ort->rt_iif; 2715 rt->rt_pmtu = ort->rt_pmtu; 2716 rt->rt_mtu_locked = ort->rt_mtu_locked; 2717 2718 rt->rt_genid = rt_genid_ipv4(net); 2719 rt->rt_flags = ort->rt_flags; 2720 rt->rt_type = ort->rt_type; 2721 rt->rt_uses_gateway = ort->rt_uses_gateway; 2722 rt->rt_gw_family = ort->rt_gw_family; 2723 if (rt->rt_gw_family == AF_INET) 2724 rt->rt_gw4 = ort->rt_gw4; 2725 else if (rt->rt_gw_family == AF_INET6) 2726 rt->rt_gw6 = ort->rt_gw6; 2727 2728 INIT_LIST_HEAD(&rt->rt_uncached); 2729 } 2730 2731 dst_release(dst_orig); 2732 2733 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2734 } 2735 2736 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2737 const struct sock *sk) 2738 { 2739 struct rtable *rt = __ip_route_output_key(net, flp4); 2740 2741 if (IS_ERR(rt)) 2742 return rt; 2743 2744 if (flp4->flowi4_proto) { 2745 flp4->flowi4_oif = rt->dst.dev->ifindex; 2746 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2747 flowi4_to_flowi(flp4), 2748 sk, 0); 2749 } 2750 2751 return rt; 2752 } 2753 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2754 2755 struct rtable *ip_route_output_tunnel(struct sk_buff *skb, 2756 struct net_device *dev, 2757 struct net *net, __be32 *saddr, 2758 const struct ip_tunnel_info *info, 2759 u8 protocol, bool use_cache) 2760 { 2761 #ifdef CONFIG_DST_CACHE 2762 struct dst_cache *dst_cache; 2763 #endif 2764 struct rtable *rt = NULL; 2765 struct flowi4 fl4; 2766 __u8 tos; 2767 2768 #ifdef CONFIG_DST_CACHE 2769 dst_cache = (struct dst_cache *)&info->dst_cache; 2770 if (use_cache) { 2771 rt = dst_cache_get_ip4(dst_cache, saddr); 2772 if (rt) 2773 return rt; 2774 } 2775 #endif 2776 memset(&fl4, 0, sizeof(fl4)); 2777 fl4.flowi4_mark = skb->mark; 2778 fl4.flowi4_proto = protocol; 2779 fl4.daddr = info->key.u.ipv4.dst; 2780 fl4.saddr = info->key.u.ipv4.src; 2781 tos = info->key.tos; 2782 fl4.flowi4_tos = RT_TOS(tos); 2783 2784 rt = ip_route_output_key(net, &fl4); 2785 if (IS_ERR(rt)) { 2786 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr); 2787 return ERR_PTR(-ENETUNREACH); 2788 } 2789 if (rt->dst.dev == dev) { /* is this necessary? */ 2790 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr); 2791 ip_rt_put(rt); 2792 return ERR_PTR(-ELOOP); 2793 } 2794 #ifdef CONFIG_DST_CACHE 2795 if (use_cache) 2796 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr); 2797 #endif 2798 *saddr = fl4.saddr; 2799 return rt; 2800 } 2801 EXPORT_SYMBOL_GPL(ip_route_output_tunnel); 2802 2803 /* called with rcu_read_lock held */ 2804 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2805 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2806 struct sk_buff *skb, u32 portid, u32 seq, 2807 unsigned int flags) 2808 { 2809 struct rtmsg *r; 2810 struct nlmsghdr *nlh; 2811 unsigned long expires = 0; 2812 u32 error; 2813 u32 metrics[RTAX_MAX]; 2814 2815 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2816 if (!nlh) 2817 return -EMSGSIZE; 2818 2819 r = nlmsg_data(nlh); 2820 r->rtm_family = AF_INET; 2821 r->rtm_dst_len = 32; 2822 r->rtm_src_len = 0; 2823 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2824 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2825 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2826 goto nla_put_failure; 2827 r->rtm_type = rt->rt_type; 2828 r->rtm_scope = RT_SCOPE_UNIVERSE; 2829 r->rtm_protocol = RTPROT_UNSPEC; 2830 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2831 if (rt->rt_flags & RTCF_NOTIFY) 2832 r->rtm_flags |= RTM_F_NOTIFY; 2833 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2834 r->rtm_flags |= RTCF_DOREDIRECT; 2835 2836 if (nla_put_in_addr(skb, RTA_DST, dst)) 2837 goto nla_put_failure; 2838 if (src) { 2839 r->rtm_src_len = 32; 2840 if (nla_put_in_addr(skb, RTA_SRC, src)) 2841 goto nla_put_failure; 2842 } 2843 if (rt->dst.dev && 2844 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2845 goto nla_put_failure; 2846 if (rt->dst.lwtstate && 2847 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) 2848 goto nla_put_failure; 2849 #ifdef CONFIG_IP_ROUTE_CLASSID 2850 if (rt->dst.tclassid && 2851 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2852 goto nla_put_failure; 2853 #endif 2854 if (fl4 && !rt_is_input_route(rt) && 2855 fl4->saddr != src) { 2856 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2857 goto nla_put_failure; 2858 } 2859 if (rt->rt_uses_gateway) { 2860 if (rt->rt_gw_family == AF_INET && 2861 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2862 goto nla_put_failure; 2863 } else if (rt->rt_gw_family == AF_INET6) { 2864 int alen = sizeof(struct in6_addr); 2865 struct nlattr *nla; 2866 struct rtvia *via; 2867 2868 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2869 if (!nla) 2870 goto nla_put_failure; 2871 2872 via = nla_data(nla); 2873 via->rtvia_family = AF_INET6; 2874 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2875 } 2876 } 2877 2878 expires = rt->dst.expires; 2879 if (expires) { 2880 unsigned long now = jiffies; 2881 2882 if (time_before(now, expires)) 2883 expires -= now; 2884 else 2885 expires = 0; 2886 } 2887 2888 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2889 if (rt->rt_pmtu && expires) 2890 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2891 if (rt->rt_mtu_locked && expires) 2892 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2893 if (rtnetlink_put_metrics(skb, metrics) < 0) 2894 goto nla_put_failure; 2895 2896 if (fl4) { 2897 if (fl4->flowi4_mark && 2898 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2899 goto nla_put_failure; 2900 2901 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2902 nla_put_u32(skb, RTA_UID, 2903 from_kuid_munged(current_user_ns(), 2904 fl4->flowi4_uid))) 2905 goto nla_put_failure; 2906 2907 if (rt_is_input_route(rt)) { 2908 #ifdef CONFIG_IP_MROUTE 2909 if (ipv4_is_multicast(dst) && 2910 !ipv4_is_local_multicast(dst) && 2911 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2912 int err = ipmr_get_route(net, skb, 2913 fl4->saddr, fl4->daddr, 2914 r, portid); 2915 2916 if (err <= 0) { 2917 if (err == 0) 2918 return 0; 2919 goto nla_put_failure; 2920 } 2921 } else 2922 #endif 2923 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2924 goto nla_put_failure; 2925 } 2926 } 2927 2928 error = rt->dst.error; 2929 2930 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2931 goto nla_put_failure; 2932 2933 nlmsg_end(skb, nlh); 2934 return 0; 2935 2936 nla_put_failure: 2937 nlmsg_cancel(skb, nlh); 2938 return -EMSGSIZE; 2939 } 2940 2941 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2942 struct netlink_callback *cb, u32 table_id, 2943 struct fnhe_hash_bucket *bucket, int genid, 2944 int *fa_index, int fa_start, unsigned int flags) 2945 { 2946 int i; 2947 2948 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2949 struct fib_nh_exception *fnhe; 2950 2951 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2952 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2953 struct rtable *rt; 2954 int err; 2955 2956 if (*fa_index < fa_start) 2957 goto next; 2958 2959 if (fnhe->fnhe_genid != genid) 2960 goto next; 2961 2962 if (fnhe->fnhe_expires && 2963 time_after(jiffies, fnhe->fnhe_expires)) 2964 goto next; 2965 2966 rt = rcu_dereference(fnhe->fnhe_rth_input); 2967 if (!rt) 2968 rt = rcu_dereference(fnhe->fnhe_rth_output); 2969 if (!rt) 2970 goto next; 2971 2972 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2973 table_id, NULL, skb, 2974 NETLINK_CB(cb->skb).portid, 2975 cb->nlh->nlmsg_seq, flags); 2976 if (err) 2977 return err; 2978 next: 2979 (*fa_index)++; 2980 } 2981 } 2982 2983 return 0; 2984 } 2985 2986 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2987 u32 table_id, struct fib_info *fi, 2988 int *fa_index, int fa_start, unsigned int flags) 2989 { 2990 struct net *net = sock_net(cb->skb->sk); 2991 int nhsel, genid = fnhe_genid(net); 2992 2993 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2994 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2995 struct fnhe_hash_bucket *bucket; 2996 int err; 2997 2998 if (nhc->nhc_flags & RTNH_F_DEAD) 2999 continue; 3000 3001 rcu_read_lock(); 3002 bucket = rcu_dereference(nhc->nhc_exceptions); 3003 err = 0; 3004 if (bucket) 3005 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 3006 genid, fa_index, fa_start, 3007 flags); 3008 rcu_read_unlock(); 3009 if (err) 3010 return err; 3011 } 3012 3013 return 0; 3014 } 3015 3016 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3017 u8 ip_proto, __be16 sport, 3018 __be16 dport) 3019 { 3020 struct sk_buff *skb; 3021 struct iphdr *iph; 3022 3023 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3024 if (!skb) 3025 return NULL; 3026 3027 /* Reserve room for dummy headers, this skb can pass 3028 * through good chunk of routing engine. 3029 */ 3030 skb_reset_mac_header(skb); 3031 skb_reset_network_header(skb); 3032 skb->protocol = htons(ETH_P_IP); 3033 iph = skb_put(skb, sizeof(struct iphdr)); 3034 iph->protocol = ip_proto; 3035 iph->saddr = src; 3036 iph->daddr = dst; 3037 iph->version = 0x4; 3038 iph->frag_off = 0; 3039 iph->ihl = 0x5; 3040 skb_set_transport_header(skb, skb->len); 3041 3042 switch (iph->protocol) { 3043 case IPPROTO_UDP: { 3044 struct udphdr *udph; 3045 3046 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3047 udph->source = sport; 3048 udph->dest = dport; 3049 udph->len = sizeof(struct udphdr); 3050 udph->check = 0; 3051 break; 3052 } 3053 case IPPROTO_TCP: { 3054 struct tcphdr *tcph; 3055 3056 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3057 tcph->source = sport; 3058 tcph->dest = dport; 3059 tcph->doff = sizeof(struct tcphdr) / 4; 3060 tcph->rst = 1; 3061 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3062 src, dst, 0); 3063 break; 3064 } 3065 case IPPROTO_ICMP: { 3066 struct icmphdr *icmph; 3067 3068 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3069 icmph->type = ICMP_ECHO; 3070 icmph->code = 0; 3071 } 3072 } 3073 3074 return skb; 3075 } 3076 3077 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3078 const struct nlmsghdr *nlh, 3079 struct nlattr **tb, 3080 struct netlink_ext_ack *extack) 3081 { 3082 struct rtmsg *rtm; 3083 int i, err; 3084 3085 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3086 NL_SET_ERR_MSG(extack, 3087 "ipv4: Invalid header for route get request"); 3088 return -EINVAL; 3089 } 3090 3091 if (!netlink_strict_get_check(skb)) 3092 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3093 rtm_ipv4_policy, extack); 3094 3095 rtm = nlmsg_data(nlh); 3096 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3097 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3098 rtm->rtm_table || rtm->rtm_protocol || 3099 rtm->rtm_scope || rtm->rtm_type) { 3100 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3101 return -EINVAL; 3102 } 3103 3104 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3105 RTM_F_LOOKUP_TABLE | 3106 RTM_F_FIB_MATCH)) { 3107 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3108 return -EINVAL; 3109 } 3110 3111 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3112 rtm_ipv4_policy, extack); 3113 if (err) 3114 return err; 3115 3116 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3117 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3118 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3119 return -EINVAL; 3120 } 3121 3122 for (i = 0; i <= RTA_MAX; i++) { 3123 if (!tb[i]) 3124 continue; 3125 3126 switch (i) { 3127 case RTA_IIF: 3128 case RTA_OIF: 3129 case RTA_SRC: 3130 case RTA_DST: 3131 case RTA_IP_PROTO: 3132 case RTA_SPORT: 3133 case RTA_DPORT: 3134 case RTA_MARK: 3135 case RTA_UID: 3136 break; 3137 default: 3138 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3139 return -EINVAL; 3140 } 3141 } 3142 3143 return 0; 3144 } 3145 3146 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3147 struct netlink_ext_ack *extack) 3148 { 3149 struct net *net = sock_net(in_skb->sk); 3150 struct nlattr *tb[RTA_MAX+1]; 3151 u32 table_id = RT_TABLE_MAIN; 3152 __be16 sport = 0, dport = 0; 3153 struct fib_result res = {}; 3154 u8 ip_proto = IPPROTO_UDP; 3155 struct rtable *rt = NULL; 3156 struct sk_buff *skb; 3157 struct rtmsg *rtm; 3158 struct flowi4 fl4 = {}; 3159 __be32 dst = 0; 3160 __be32 src = 0; 3161 kuid_t uid; 3162 u32 iif; 3163 int err; 3164 int mark; 3165 3166 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3167 if (err < 0) 3168 return err; 3169 3170 rtm = nlmsg_data(nlh); 3171 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3172 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3173 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3174 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3175 if (tb[RTA_UID]) 3176 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3177 else 3178 uid = (iif ? INVALID_UID : current_uid()); 3179 3180 if (tb[RTA_IP_PROTO]) { 3181 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3182 &ip_proto, AF_INET, extack); 3183 if (err) 3184 return err; 3185 } 3186 3187 if (tb[RTA_SPORT]) 3188 sport = nla_get_be16(tb[RTA_SPORT]); 3189 3190 if (tb[RTA_DPORT]) 3191 dport = nla_get_be16(tb[RTA_DPORT]); 3192 3193 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3194 if (!skb) 3195 return -ENOBUFS; 3196 3197 fl4.daddr = dst; 3198 fl4.saddr = src; 3199 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK; 3200 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3201 fl4.flowi4_mark = mark; 3202 fl4.flowi4_uid = uid; 3203 if (sport) 3204 fl4.fl4_sport = sport; 3205 if (dport) 3206 fl4.fl4_dport = dport; 3207 fl4.flowi4_proto = ip_proto; 3208 3209 rcu_read_lock(); 3210 3211 if (iif) { 3212 struct net_device *dev; 3213 3214 dev = dev_get_by_index_rcu(net, iif); 3215 if (!dev) { 3216 err = -ENODEV; 3217 goto errout_rcu; 3218 } 3219 3220 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3221 skb->dev = dev; 3222 skb->mark = mark; 3223 err = ip_route_input_rcu(skb, dst, src, 3224 rtm->rtm_tos & IPTOS_RT_MASK, dev, 3225 &res); 3226 3227 rt = skb_rtable(skb); 3228 if (err == 0 && rt->dst.error) 3229 err = -rt->dst.error; 3230 } else { 3231 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3232 skb->dev = net->loopback_dev; 3233 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3234 err = 0; 3235 if (IS_ERR(rt)) 3236 err = PTR_ERR(rt); 3237 else 3238 skb_dst_set(skb, &rt->dst); 3239 } 3240 3241 if (err) 3242 goto errout_rcu; 3243 3244 if (rtm->rtm_flags & RTM_F_NOTIFY) 3245 rt->rt_flags |= RTCF_NOTIFY; 3246 3247 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3248 table_id = res.table ? res.table->tb_id : 0; 3249 3250 /* reset skb for netlink reply msg */ 3251 skb_trim(skb, 0); 3252 skb_reset_network_header(skb); 3253 skb_reset_transport_header(skb); 3254 skb_reset_mac_header(skb); 3255 3256 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3257 struct fib_rt_info fri; 3258 3259 if (!res.fi) { 3260 err = fib_props[res.type].error; 3261 if (!err) 3262 err = -EHOSTUNREACH; 3263 goto errout_rcu; 3264 } 3265 fri.fi = res.fi; 3266 fri.tb_id = table_id; 3267 fri.dst = res.prefix; 3268 fri.dst_len = res.prefixlen; 3269 fri.tos = fl4.flowi4_tos; 3270 fri.type = rt->rt_type; 3271 fri.offload = 0; 3272 fri.trap = 0; 3273 fri.offload_failed = 0; 3274 if (res.fa_head) { 3275 struct fib_alias *fa; 3276 3277 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3278 u8 slen = 32 - fri.dst_len; 3279 3280 if (fa->fa_slen == slen && 3281 fa->tb_id == fri.tb_id && 3282 fa->fa_tos == fri.tos && 3283 fa->fa_info == res.fi && 3284 fa->fa_type == fri.type) { 3285 fri.offload = fa->offload; 3286 fri.trap = fa->trap; 3287 break; 3288 } 3289 } 3290 } 3291 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3292 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3293 } else { 3294 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3295 NETLINK_CB(in_skb).portid, 3296 nlh->nlmsg_seq, 0); 3297 } 3298 if (err < 0) 3299 goto errout_rcu; 3300 3301 rcu_read_unlock(); 3302 3303 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3304 3305 errout_free: 3306 return err; 3307 errout_rcu: 3308 rcu_read_unlock(); 3309 kfree_skb(skb); 3310 goto errout_free; 3311 } 3312 3313 void ip_rt_multicast_event(struct in_device *in_dev) 3314 { 3315 rt_cache_flush(dev_net(in_dev->dev)); 3316 } 3317 3318 #ifdef CONFIG_SYSCTL 3319 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3320 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3321 static int ip_rt_gc_elasticity __read_mostly = 8; 3322 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3323 3324 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3325 void *buffer, size_t *lenp, loff_t *ppos) 3326 { 3327 struct net *net = (struct net *)__ctl->extra1; 3328 3329 if (write) { 3330 rt_cache_flush(net); 3331 fnhe_genid_bump(net); 3332 return 0; 3333 } 3334 3335 return -EINVAL; 3336 } 3337 3338 static struct ctl_table ipv4_route_table[] = { 3339 { 3340 .procname = "gc_thresh", 3341 .data = &ipv4_dst_ops.gc_thresh, 3342 .maxlen = sizeof(int), 3343 .mode = 0644, 3344 .proc_handler = proc_dointvec, 3345 }, 3346 { 3347 .procname = "max_size", 3348 .data = &ip_rt_max_size, 3349 .maxlen = sizeof(int), 3350 .mode = 0644, 3351 .proc_handler = proc_dointvec, 3352 }, 3353 { 3354 /* Deprecated. Use gc_min_interval_ms */ 3355 3356 .procname = "gc_min_interval", 3357 .data = &ip_rt_gc_min_interval, 3358 .maxlen = sizeof(int), 3359 .mode = 0644, 3360 .proc_handler = proc_dointvec_jiffies, 3361 }, 3362 { 3363 .procname = "gc_min_interval_ms", 3364 .data = &ip_rt_gc_min_interval, 3365 .maxlen = sizeof(int), 3366 .mode = 0644, 3367 .proc_handler = proc_dointvec_ms_jiffies, 3368 }, 3369 { 3370 .procname = "gc_timeout", 3371 .data = &ip_rt_gc_timeout, 3372 .maxlen = sizeof(int), 3373 .mode = 0644, 3374 .proc_handler = proc_dointvec_jiffies, 3375 }, 3376 { 3377 .procname = "gc_interval", 3378 .data = &ip_rt_gc_interval, 3379 .maxlen = sizeof(int), 3380 .mode = 0644, 3381 .proc_handler = proc_dointvec_jiffies, 3382 }, 3383 { 3384 .procname = "redirect_load", 3385 .data = &ip_rt_redirect_load, 3386 .maxlen = sizeof(int), 3387 .mode = 0644, 3388 .proc_handler = proc_dointvec, 3389 }, 3390 { 3391 .procname = "redirect_number", 3392 .data = &ip_rt_redirect_number, 3393 .maxlen = sizeof(int), 3394 .mode = 0644, 3395 .proc_handler = proc_dointvec, 3396 }, 3397 { 3398 .procname = "redirect_silence", 3399 .data = &ip_rt_redirect_silence, 3400 .maxlen = sizeof(int), 3401 .mode = 0644, 3402 .proc_handler = proc_dointvec, 3403 }, 3404 { 3405 .procname = "error_cost", 3406 .data = &ip_rt_error_cost, 3407 .maxlen = sizeof(int), 3408 .mode = 0644, 3409 .proc_handler = proc_dointvec, 3410 }, 3411 { 3412 .procname = "error_burst", 3413 .data = &ip_rt_error_burst, 3414 .maxlen = sizeof(int), 3415 .mode = 0644, 3416 .proc_handler = proc_dointvec, 3417 }, 3418 { 3419 .procname = "gc_elasticity", 3420 .data = &ip_rt_gc_elasticity, 3421 .maxlen = sizeof(int), 3422 .mode = 0644, 3423 .proc_handler = proc_dointvec, 3424 }, 3425 { 3426 .procname = "mtu_expires", 3427 .data = &ip_rt_mtu_expires, 3428 .maxlen = sizeof(int), 3429 .mode = 0644, 3430 .proc_handler = proc_dointvec_jiffies, 3431 }, 3432 { 3433 .procname = "min_pmtu", 3434 .data = &ip_rt_min_pmtu, 3435 .maxlen = sizeof(int), 3436 .mode = 0644, 3437 .proc_handler = proc_dointvec_minmax, 3438 .extra1 = &ip_min_valid_pmtu, 3439 }, 3440 { 3441 .procname = "min_adv_mss", 3442 .data = &ip_rt_min_advmss, 3443 .maxlen = sizeof(int), 3444 .mode = 0644, 3445 .proc_handler = proc_dointvec, 3446 }, 3447 { } 3448 }; 3449 3450 static const char ipv4_route_flush_procname[] = "flush"; 3451 3452 static struct ctl_table ipv4_route_flush_table[] = { 3453 { 3454 .procname = ipv4_route_flush_procname, 3455 .maxlen = sizeof(int), 3456 .mode = 0200, 3457 .proc_handler = ipv4_sysctl_rtcache_flush, 3458 }, 3459 { }, 3460 }; 3461 3462 static __net_init int sysctl_route_net_init(struct net *net) 3463 { 3464 struct ctl_table *tbl; 3465 3466 tbl = ipv4_route_flush_table; 3467 if (!net_eq(net, &init_net)) { 3468 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3469 if (!tbl) 3470 goto err_dup; 3471 3472 /* Don't export non-whitelisted sysctls to unprivileged users */ 3473 if (net->user_ns != &init_user_ns) { 3474 if (tbl[0].procname != ipv4_route_flush_procname) 3475 tbl[0].procname = NULL; 3476 } 3477 } 3478 tbl[0].extra1 = net; 3479 3480 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3481 if (!net->ipv4.route_hdr) 3482 goto err_reg; 3483 return 0; 3484 3485 err_reg: 3486 if (tbl != ipv4_route_flush_table) 3487 kfree(tbl); 3488 err_dup: 3489 return -ENOMEM; 3490 } 3491 3492 static __net_exit void sysctl_route_net_exit(struct net *net) 3493 { 3494 struct ctl_table *tbl; 3495 3496 tbl = net->ipv4.route_hdr->ctl_table_arg; 3497 unregister_net_sysctl_table(net->ipv4.route_hdr); 3498 BUG_ON(tbl == ipv4_route_flush_table); 3499 kfree(tbl); 3500 } 3501 3502 static __net_initdata struct pernet_operations sysctl_route_ops = { 3503 .init = sysctl_route_net_init, 3504 .exit = sysctl_route_net_exit, 3505 }; 3506 #endif 3507 3508 static __net_init int rt_genid_init(struct net *net) 3509 { 3510 atomic_set(&net->ipv4.rt_genid, 0); 3511 atomic_set(&net->fnhe_genid, 0); 3512 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3513 return 0; 3514 } 3515 3516 static __net_initdata struct pernet_operations rt_genid_ops = { 3517 .init = rt_genid_init, 3518 }; 3519 3520 static int __net_init ipv4_inetpeer_init(struct net *net) 3521 { 3522 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3523 3524 if (!bp) 3525 return -ENOMEM; 3526 inet_peer_base_init(bp); 3527 net->ipv4.peers = bp; 3528 return 0; 3529 } 3530 3531 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3532 { 3533 struct inet_peer_base *bp = net->ipv4.peers; 3534 3535 net->ipv4.peers = NULL; 3536 inetpeer_invalidate_tree(bp); 3537 kfree(bp); 3538 } 3539 3540 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3541 .init = ipv4_inetpeer_init, 3542 .exit = ipv4_inetpeer_exit, 3543 }; 3544 3545 #ifdef CONFIG_IP_ROUTE_CLASSID 3546 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3547 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3548 3549 int __init ip_rt_init(void) 3550 { 3551 void *idents_hash; 3552 int cpu; 3553 3554 /* For modern hosts, this will use 2 MB of memory */ 3555 idents_hash = alloc_large_system_hash("IP idents", 3556 sizeof(*ip_idents) + sizeof(*ip_tstamps), 3557 0, 3558 16, /* one bucket per 64 KB */ 3559 HASH_ZERO, 3560 NULL, 3561 &ip_idents_mask, 3562 2048, 3563 256*1024); 3564 3565 ip_idents = idents_hash; 3566 3567 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents)); 3568 3569 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents); 3570 3571 for_each_possible_cpu(cpu) { 3572 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3573 3574 INIT_LIST_HEAD(&ul->head); 3575 spin_lock_init(&ul->lock); 3576 } 3577 #ifdef CONFIG_IP_ROUTE_CLASSID 3578 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3579 if (!ip_rt_acct) 3580 panic("IP: failed to allocate ip_rt_acct\n"); 3581 #endif 3582 3583 ipv4_dst_ops.kmem_cachep = 3584 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3585 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3586 3587 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3588 3589 if (dst_entries_init(&ipv4_dst_ops) < 0) 3590 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3591 3592 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3593 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3594 3595 ipv4_dst_ops.gc_thresh = ~0; 3596 ip_rt_max_size = INT_MAX; 3597 3598 devinet_init(); 3599 ip_fib_init(); 3600 3601 if (ip_rt_proc_init()) 3602 pr_err("Unable to create route proc files\n"); 3603 #ifdef CONFIG_XFRM 3604 xfrm_init(); 3605 xfrm4_init(); 3606 #endif 3607 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3608 RTNL_FLAG_DOIT_UNLOCKED); 3609 3610 #ifdef CONFIG_SYSCTL 3611 register_pernet_subsys(&sysctl_route_ops); 3612 #endif 3613 register_pernet_subsys(&rt_genid_ops); 3614 register_pernet_subsys(&ipv4_inetpeer_ops); 3615 return 0; 3616 } 3617 3618 #ifdef CONFIG_SYSCTL 3619 /* 3620 * We really need to sanitize the damn ipv4 init order, then all 3621 * this nonsense will go away. 3622 */ 3623 void __init ip_static_sysctl_init(void) 3624 { 3625 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3626 } 3627 #endif 3628