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/string.h> 70 #include <linux/socket.h> 71 #include <linux/sockios.h> 72 #include <linux/errno.h> 73 #include <linux/in.h> 74 #include <linux/inet.h> 75 #include <linux/netdevice.h> 76 #include <linux/proc_fs.h> 77 #include <linux/init.h> 78 #include <linux/skbuff.h> 79 #include <linux/inetdevice.h> 80 #include <linux/igmp.h> 81 #include <linux/pkt_sched.h> 82 #include <linux/mroute.h> 83 #include <linux/netfilter_ipv4.h> 84 #include <linux/random.h> 85 #include <linux/rcupdate.h> 86 #include <linux/times.h> 87 #include <linux/slab.h> 88 #include <linux/jhash.h> 89 #include <net/dst.h> 90 #include <net/dst_metadata.h> 91 #include <net/net_namespace.h> 92 #include <net/protocol.h> 93 #include <net/ip.h> 94 #include <net/route.h> 95 #include <net/inetpeer.h> 96 #include <net/sock.h> 97 #include <net/ip_fib.h> 98 #include <net/nexthop.h> 99 #include <net/arp.h> 100 #include <net/tcp.h> 101 #include <net/icmp.h> 102 #include <net/xfrm.h> 103 #include <net/lwtunnel.h> 104 #include <net/netevent.h> 105 #include <net/rtnetlink.h> 106 #ifdef CONFIG_SYSCTL 107 #include <linux/sysctl.h> 108 #endif 109 #include <net/secure_seq.h> 110 #include <net/ip_tunnels.h> 111 #include <net/l3mdev.h> 112 113 #include "fib_lookup.h" 114 115 #define RT_FL_TOS(oldflp4) \ 116 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 117 118 #define RT_GC_TIMEOUT (300*HZ) 119 120 static int ip_rt_max_size; 121 static int ip_rt_redirect_number __read_mostly = 9; 122 static int ip_rt_redirect_load __read_mostly = HZ / 50; 123 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 124 static int ip_rt_error_cost __read_mostly = HZ; 125 static int ip_rt_error_burst __read_mostly = 5 * HZ; 126 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 127 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 128 static int ip_rt_min_advmss __read_mostly = 256; 129 130 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 131 132 /* 133 * Interface to generic destination cache. 134 */ 135 136 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 137 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 138 static unsigned int ipv4_mtu(const struct dst_entry *dst); 139 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 140 static void ipv4_link_failure(struct sk_buff *skb); 141 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 142 struct sk_buff *skb, u32 mtu); 143 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 144 struct sk_buff *skb); 145 static void ipv4_dst_destroy(struct dst_entry *dst); 146 147 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 148 { 149 WARN_ON(1); 150 return NULL; 151 } 152 153 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 154 struct sk_buff *skb, 155 const void *daddr); 156 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 157 158 static struct dst_ops ipv4_dst_ops = { 159 .family = AF_INET, 160 .check = ipv4_dst_check, 161 .default_advmss = ipv4_default_advmss, 162 .mtu = ipv4_mtu, 163 .cow_metrics = ipv4_cow_metrics, 164 .destroy = ipv4_dst_destroy, 165 .negative_advice = ipv4_negative_advice, 166 .link_failure = ipv4_link_failure, 167 .update_pmtu = ip_rt_update_pmtu, 168 .redirect = ip_do_redirect, 169 .local_out = __ip_local_out, 170 .neigh_lookup = ipv4_neigh_lookup, 171 .confirm_neigh = ipv4_confirm_neigh, 172 }; 173 174 #define ECN_OR_COST(class) TC_PRIO_##class 175 176 const __u8 ip_tos2prio[16] = { 177 TC_PRIO_BESTEFFORT, 178 ECN_OR_COST(BESTEFFORT), 179 TC_PRIO_BESTEFFORT, 180 ECN_OR_COST(BESTEFFORT), 181 TC_PRIO_BULK, 182 ECN_OR_COST(BULK), 183 TC_PRIO_BULK, 184 ECN_OR_COST(BULK), 185 TC_PRIO_INTERACTIVE, 186 ECN_OR_COST(INTERACTIVE), 187 TC_PRIO_INTERACTIVE, 188 ECN_OR_COST(INTERACTIVE), 189 TC_PRIO_INTERACTIVE_BULK, 190 ECN_OR_COST(INTERACTIVE_BULK), 191 TC_PRIO_INTERACTIVE_BULK, 192 ECN_OR_COST(INTERACTIVE_BULK) 193 }; 194 EXPORT_SYMBOL(ip_tos2prio); 195 196 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 197 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 198 199 #ifdef CONFIG_PROC_FS 200 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 201 { 202 if (*pos) 203 return NULL; 204 return SEQ_START_TOKEN; 205 } 206 207 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 208 { 209 ++*pos; 210 return NULL; 211 } 212 213 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 214 { 215 } 216 217 static int rt_cache_seq_show(struct seq_file *seq, void *v) 218 { 219 if (v == SEQ_START_TOKEN) 220 seq_printf(seq, "%-127s\n", 221 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 222 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 223 "HHUptod\tSpecDst"); 224 return 0; 225 } 226 227 static const struct seq_operations rt_cache_seq_ops = { 228 .start = rt_cache_seq_start, 229 .next = rt_cache_seq_next, 230 .stop = rt_cache_seq_stop, 231 .show = rt_cache_seq_show, 232 }; 233 234 static int rt_cache_seq_open(struct inode *inode, struct file *file) 235 { 236 return seq_open(file, &rt_cache_seq_ops); 237 } 238 239 static const struct file_operations rt_cache_seq_fops = { 240 .open = rt_cache_seq_open, 241 .read = seq_read, 242 .llseek = seq_lseek, 243 .release = seq_release, 244 }; 245 246 247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 248 { 249 int cpu; 250 251 if (*pos == 0) 252 return SEQ_START_TOKEN; 253 254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 255 if (!cpu_possible(cpu)) 256 continue; 257 *pos = cpu+1; 258 return &per_cpu(rt_cache_stat, cpu); 259 } 260 return NULL; 261 } 262 263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 264 { 265 int cpu; 266 267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 268 if (!cpu_possible(cpu)) 269 continue; 270 *pos = cpu+1; 271 return &per_cpu(rt_cache_stat, cpu); 272 } 273 return NULL; 274 275 } 276 277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 278 { 279 280 } 281 282 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 283 { 284 struct rt_cache_stat *st = v; 285 286 if (v == SEQ_START_TOKEN) { 287 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"); 288 return 0; 289 } 290 291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 293 dst_entries_get_slow(&ipv4_dst_ops), 294 0, /* st->in_hit */ 295 st->in_slow_tot, 296 st->in_slow_mc, 297 st->in_no_route, 298 st->in_brd, 299 st->in_martian_dst, 300 st->in_martian_src, 301 302 0, /* st->out_hit */ 303 st->out_slow_tot, 304 st->out_slow_mc, 305 306 0, /* st->gc_total */ 307 0, /* st->gc_ignored */ 308 0, /* st->gc_goal_miss */ 309 0, /* st->gc_dst_overflow */ 310 0, /* st->in_hlist_search */ 311 0 /* st->out_hlist_search */ 312 ); 313 return 0; 314 } 315 316 static const struct seq_operations rt_cpu_seq_ops = { 317 .start = rt_cpu_seq_start, 318 .next = rt_cpu_seq_next, 319 .stop = rt_cpu_seq_stop, 320 .show = rt_cpu_seq_show, 321 }; 322 323 324 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 325 { 326 return seq_open(file, &rt_cpu_seq_ops); 327 } 328 329 static const struct file_operations rt_cpu_seq_fops = { 330 .open = rt_cpu_seq_open, 331 .read = seq_read, 332 .llseek = seq_lseek, 333 .release = seq_release, 334 }; 335 336 #ifdef CONFIG_IP_ROUTE_CLASSID 337 static int rt_acct_proc_show(struct seq_file *m, void *v) 338 { 339 struct ip_rt_acct *dst, *src; 340 unsigned int i, j; 341 342 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 343 if (!dst) 344 return -ENOMEM; 345 346 for_each_possible_cpu(i) { 347 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 348 for (j = 0; j < 256; j++) { 349 dst[j].o_bytes += src[j].o_bytes; 350 dst[j].o_packets += src[j].o_packets; 351 dst[j].i_bytes += src[j].i_bytes; 352 dst[j].i_packets += src[j].i_packets; 353 } 354 } 355 356 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 357 kfree(dst); 358 return 0; 359 } 360 #endif 361 362 static int __net_init ip_rt_do_proc_init(struct net *net) 363 { 364 struct proc_dir_entry *pde; 365 366 pde = proc_create("rt_cache", 0444, net->proc_net, 367 &rt_cache_seq_fops); 368 if (!pde) 369 goto err1; 370 371 pde = proc_create("rt_cache", 0444, 372 net->proc_net_stat, &rt_cpu_seq_fops); 373 if (!pde) 374 goto err2; 375 376 #ifdef CONFIG_IP_ROUTE_CLASSID 377 pde = proc_create_single("rt_acct", 0, net->proc_net, 378 rt_acct_proc_show); 379 if (!pde) 380 goto err3; 381 #endif 382 return 0; 383 384 #ifdef CONFIG_IP_ROUTE_CLASSID 385 err3: 386 remove_proc_entry("rt_cache", net->proc_net_stat); 387 #endif 388 err2: 389 remove_proc_entry("rt_cache", net->proc_net); 390 err1: 391 return -ENOMEM; 392 } 393 394 static void __net_exit ip_rt_do_proc_exit(struct net *net) 395 { 396 remove_proc_entry("rt_cache", net->proc_net_stat); 397 remove_proc_entry("rt_cache", net->proc_net); 398 #ifdef CONFIG_IP_ROUTE_CLASSID 399 remove_proc_entry("rt_acct", net->proc_net); 400 #endif 401 } 402 403 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 404 .init = ip_rt_do_proc_init, 405 .exit = ip_rt_do_proc_exit, 406 }; 407 408 static int __init ip_rt_proc_init(void) 409 { 410 return register_pernet_subsys(&ip_rt_proc_ops); 411 } 412 413 #else 414 static inline int ip_rt_proc_init(void) 415 { 416 return 0; 417 } 418 #endif /* CONFIG_PROC_FS */ 419 420 static inline bool rt_is_expired(const struct rtable *rth) 421 { 422 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 423 } 424 425 void rt_cache_flush(struct net *net) 426 { 427 rt_genid_bump_ipv4(net); 428 } 429 430 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 431 struct sk_buff *skb, 432 const void *daddr) 433 { 434 const struct rtable *rt = container_of(dst, struct rtable, dst); 435 struct net_device *dev = dst->dev; 436 struct neighbour *n; 437 438 rcu_read_lock_bh(); 439 440 if (likely(rt->rt_gw_family == AF_INET)) { 441 n = ip_neigh_gw4(dev, rt->rt_gw4); 442 } else if (rt->rt_gw_family == AF_INET6) { 443 n = ip_neigh_gw6(dev, &rt->rt_gw6); 444 } else { 445 __be32 pkey; 446 447 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 448 n = ip_neigh_gw4(dev, pkey); 449 } 450 451 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 452 n = NULL; 453 454 rcu_read_unlock_bh(); 455 456 return n; 457 } 458 459 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 460 { 461 const struct rtable *rt = container_of(dst, struct rtable, dst); 462 struct net_device *dev = dst->dev; 463 const __be32 *pkey = daddr; 464 465 if (rt->rt_gw_family == AF_INET) { 466 pkey = (const __be32 *)&rt->rt_gw4; 467 } else if (rt->rt_gw_family == AF_INET6) { 468 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 469 } else if (!daddr || 470 (rt->rt_flags & 471 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 472 return; 473 } 474 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 475 } 476 477 #define IP_IDENTS_SZ 2048u 478 479 static atomic_t *ip_idents __read_mostly; 480 static u32 *ip_tstamps __read_mostly; 481 482 /* In order to protect privacy, we add a perturbation to identifiers 483 * if one generator is seldom used. This makes hard for an attacker 484 * to infer how many packets were sent between two points in time. 485 */ 486 u32 ip_idents_reserve(u32 hash, int segs) 487 { 488 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 489 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 490 u32 old = READ_ONCE(*p_tstamp); 491 u32 now = (u32)jiffies; 492 u32 new, delta = 0; 493 494 if (old != now && cmpxchg(p_tstamp, old, now) == old) 495 delta = prandom_u32_max(now - old); 496 497 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 498 do { 499 old = (u32)atomic_read(p_id); 500 new = old + delta + segs; 501 } while (atomic_cmpxchg(p_id, old, new) != old); 502 503 return new - segs; 504 } 505 EXPORT_SYMBOL(ip_idents_reserve); 506 507 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 508 { 509 u32 hash, id; 510 511 /* Note the following code is not safe, but this is okay. */ 512 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 513 get_random_bytes(&net->ipv4.ip_id_key, 514 sizeof(net->ipv4.ip_id_key)); 515 516 hash = siphash_3u32((__force u32)iph->daddr, 517 (__force u32)iph->saddr, 518 iph->protocol, 519 &net->ipv4.ip_id_key); 520 id = ip_idents_reserve(hash, segs); 521 iph->id = htons(id); 522 } 523 EXPORT_SYMBOL(__ip_select_ident); 524 525 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 526 const struct sock *sk, 527 const struct iphdr *iph, 528 int oif, u8 tos, 529 u8 prot, u32 mark, int flow_flags) 530 { 531 if (sk) { 532 const struct inet_sock *inet = inet_sk(sk); 533 534 oif = sk->sk_bound_dev_if; 535 mark = sk->sk_mark; 536 tos = RT_CONN_FLAGS(sk); 537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 538 } 539 flowi4_init_output(fl4, oif, mark, tos, 540 RT_SCOPE_UNIVERSE, prot, 541 flow_flags, 542 iph->daddr, iph->saddr, 0, 0, 543 sock_net_uid(net, sk)); 544 } 545 546 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 547 const struct sock *sk) 548 { 549 const struct net *net = dev_net(skb->dev); 550 const struct iphdr *iph = ip_hdr(skb); 551 int oif = skb->dev->ifindex; 552 u8 tos = RT_TOS(iph->tos); 553 u8 prot = iph->protocol; 554 u32 mark = skb->mark; 555 556 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 557 } 558 559 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 560 { 561 const struct inet_sock *inet = inet_sk(sk); 562 const struct ip_options_rcu *inet_opt; 563 __be32 daddr = inet->inet_daddr; 564 565 rcu_read_lock(); 566 inet_opt = rcu_dereference(inet->inet_opt); 567 if (inet_opt && inet_opt->opt.srr) 568 daddr = inet_opt->opt.faddr; 569 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 570 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 571 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 572 inet_sk_flowi_flags(sk), 573 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 574 rcu_read_unlock(); 575 } 576 577 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 578 const struct sk_buff *skb) 579 { 580 if (skb) 581 build_skb_flow_key(fl4, skb, sk); 582 else 583 build_sk_flow_key(fl4, sk); 584 } 585 586 static DEFINE_SPINLOCK(fnhe_lock); 587 588 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 589 { 590 struct rtable *rt; 591 592 rt = rcu_dereference(fnhe->fnhe_rth_input); 593 if (rt) { 594 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 595 dst_dev_put(&rt->dst); 596 dst_release(&rt->dst); 597 } 598 rt = rcu_dereference(fnhe->fnhe_rth_output); 599 if (rt) { 600 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 601 dst_dev_put(&rt->dst); 602 dst_release(&rt->dst); 603 } 604 } 605 606 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 607 { 608 struct fib_nh_exception *fnhe, *oldest; 609 610 oldest = rcu_dereference(hash->chain); 611 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 612 fnhe = rcu_dereference(fnhe->fnhe_next)) { 613 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 614 oldest = fnhe; 615 } 616 fnhe_flush_routes(oldest); 617 return oldest; 618 } 619 620 static inline u32 fnhe_hashfun(__be32 daddr) 621 { 622 static u32 fnhe_hashrnd __read_mostly; 623 u32 hval; 624 625 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 626 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 627 return hash_32(hval, FNHE_HASH_SHIFT); 628 } 629 630 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 631 { 632 rt->rt_pmtu = fnhe->fnhe_pmtu; 633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 634 rt->dst.expires = fnhe->fnhe_expires; 635 636 if (fnhe->fnhe_gw) { 637 rt->rt_flags |= RTCF_REDIRECTED; 638 rt->rt_uses_gateway = 1; 639 rt->rt_gw_family = AF_INET; 640 rt->rt_gw4 = fnhe->fnhe_gw; 641 } 642 } 643 644 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 645 __be32 gw, u32 pmtu, bool lock, 646 unsigned long expires) 647 { 648 struct fnhe_hash_bucket *hash; 649 struct fib_nh_exception *fnhe; 650 struct rtable *rt; 651 u32 genid, hval; 652 unsigned int i; 653 int depth; 654 655 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 656 hval = fnhe_hashfun(daddr); 657 658 spin_lock_bh(&fnhe_lock); 659 660 hash = rcu_dereference(nhc->nhc_exceptions); 661 if (!hash) { 662 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 663 if (!hash) 664 goto out_unlock; 665 rcu_assign_pointer(nhc->nhc_exceptions, hash); 666 } 667 668 hash += hval; 669 670 depth = 0; 671 for (fnhe = rcu_dereference(hash->chain); fnhe; 672 fnhe = rcu_dereference(fnhe->fnhe_next)) { 673 if (fnhe->fnhe_daddr == daddr) 674 break; 675 depth++; 676 } 677 678 if (fnhe) { 679 if (fnhe->fnhe_genid != genid) 680 fnhe->fnhe_genid = genid; 681 if (gw) 682 fnhe->fnhe_gw = gw; 683 if (pmtu) { 684 fnhe->fnhe_pmtu = pmtu; 685 fnhe->fnhe_mtu_locked = lock; 686 } 687 fnhe->fnhe_expires = max(1UL, expires); 688 /* Update all cached dsts too */ 689 rt = rcu_dereference(fnhe->fnhe_rth_input); 690 if (rt) 691 fill_route_from_fnhe(rt, fnhe); 692 rt = rcu_dereference(fnhe->fnhe_rth_output); 693 if (rt) 694 fill_route_from_fnhe(rt, fnhe); 695 } else { 696 if (depth > FNHE_RECLAIM_DEPTH) 697 fnhe = fnhe_oldest(hash); 698 else { 699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 700 if (!fnhe) 701 goto out_unlock; 702 703 fnhe->fnhe_next = hash->chain; 704 rcu_assign_pointer(hash->chain, fnhe); 705 } 706 fnhe->fnhe_genid = genid; 707 fnhe->fnhe_daddr = daddr; 708 fnhe->fnhe_gw = gw; 709 fnhe->fnhe_pmtu = pmtu; 710 fnhe->fnhe_mtu_locked = lock; 711 fnhe->fnhe_expires = max(1UL, expires); 712 713 /* Exception created; mark the cached routes for the nexthop 714 * stale, so anyone caching it rechecks if this exception 715 * applies to them. 716 */ 717 rt = rcu_dereference(nhc->nhc_rth_input); 718 if (rt) 719 rt->dst.obsolete = DST_OBSOLETE_KILL; 720 721 for_each_possible_cpu(i) { 722 struct rtable __rcu **prt; 723 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 724 rt = rcu_dereference(*prt); 725 if (rt) 726 rt->dst.obsolete = DST_OBSOLETE_KILL; 727 } 728 } 729 730 fnhe->fnhe_stamp = jiffies; 731 732 out_unlock: 733 spin_unlock_bh(&fnhe_lock); 734 } 735 736 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 737 bool kill_route) 738 { 739 __be32 new_gw = icmp_hdr(skb)->un.gateway; 740 __be32 old_gw = ip_hdr(skb)->saddr; 741 struct net_device *dev = skb->dev; 742 struct in_device *in_dev; 743 struct fib_result res; 744 struct neighbour *n; 745 struct net *net; 746 747 switch (icmp_hdr(skb)->code & 7) { 748 case ICMP_REDIR_NET: 749 case ICMP_REDIR_NETTOS: 750 case ICMP_REDIR_HOST: 751 case ICMP_REDIR_HOSTTOS: 752 break; 753 754 default: 755 return; 756 } 757 758 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 759 return; 760 761 in_dev = __in_dev_get_rcu(dev); 762 if (!in_dev) 763 return; 764 765 net = dev_net(dev); 766 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 767 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 768 ipv4_is_zeronet(new_gw)) 769 goto reject_redirect; 770 771 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 772 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 773 goto reject_redirect; 774 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 775 goto reject_redirect; 776 } else { 777 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 778 goto reject_redirect; 779 } 780 781 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 782 if (!n) 783 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 784 if (!IS_ERR(n)) { 785 if (!(n->nud_state & NUD_VALID)) { 786 neigh_event_send(n, NULL); 787 } else { 788 if (fib_lookup(net, fl4, &res, 0) == 0) { 789 struct fib_nh_common *nhc = FIB_RES_NHC(res); 790 791 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 792 0, false, 793 jiffies + ip_rt_gc_timeout); 794 } 795 if (kill_route) 796 rt->dst.obsolete = DST_OBSOLETE_KILL; 797 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 798 } 799 neigh_release(n); 800 } 801 return; 802 803 reject_redirect: 804 #ifdef CONFIG_IP_ROUTE_VERBOSE 805 if (IN_DEV_LOG_MARTIANS(in_dev)) { 806 const struct iphdr *iph = (const struct iphdr *) skb->data; 807 __be32 daddr = iph->daddr; 808 __be32 saddr = iph->saddr; 809 810 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 811 " Advised path = %pI4 -> %pI4\n", 812 &old_gw, dev->name, &new_gw, 813 &saddr, &daddr); 814 } 815 #endif 816 ; 817 } 818 819 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 820 { 821 struct rtable *rt; 822 struct flowi4 fl4; 823 const struct iphdr *iph = (const struct iphdr *) skb->data; 824 struct net *net = dev_net(skb->dev); 825 int oif = skb->dev->ifindex; 826 u8 tos = RT_TOS(iph->tos); 827 u8 prot = iph->protocol; 828 u32 mark = skb->mark; 829 830 rt = (struct rtable *) dst; 831 832 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 833 __ip_do_redirect(rt, skb, &fl4, true); 834 } 835 836 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 837 { 838 struct rtable *rt = (struct rtable *)dst; 839 struct dst_entry *ret = dst; 840 841 if (rt) { 842 if (dst->obsolete > 0) { 843 ip_rt_put(rt); 844 ret = NULL; 845 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 846 rt->dst.expires) { 847 ip_rt_put(rt); 848 ret = NULL; 849 } 850 } 851 return ret; 852 } 853 854 /* 855 * Algorithm: 856 * 1. The first ip_rt_redirect_number redirects are sent 857 * with exponential backoff, then we stop sending them at all, 858 * assuming that the host ignores our redirects. 859 * 2. If we did not see packets requiring redirects 860 * during ip_rt_redirect_silence, we assume that the host 861 * forgot redirected route and start to send redirects again. 862 * 863 * This algorithm is much cheaper and more intelligent than dumb load limiting 864 * in icmp.c. 865 * 866 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 867 * and "frag. need" (breaks PMTU discovery) in icmp.c. 868 */ 869 870 void ip_rt_send_redirect(struct sk_buff *skb) 871 { 872 struct rtable *rt = skb_rtable(skb); 873 struct in_device *in_dev; 874 struct inet_peer *peer; 875 struct net *net; 876 int log_martians; 877 int vif; 878 879 rcu_read_lock(); 880 in_dev = __in_dev_get_rcu(rt->dst.dev); 881 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 882 rcu_read_unlock(); 883 return; 884 } 885 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 886 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 887 rcu_read_unlock(); 888 889 net = dev_net(rt->dst.dev); 890 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 891 if (!peer) { 892 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 893 rt_nexthop(rt, ip_hdr(skb)->daddr)); 894 return; 895 } 896 897 /* No redirected packets during ip_rt_redirect_silence; 898 * reset the algorithm. 899 */ 900 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 901 peer->rate_tokens = 0; 902 peer->n_redirects = 0; 903 } 904 905 /* Too many ignored redirects; do not send anything 906 * set dst.rate_last to the last seen redirected packet. 907 */ 908 if (peer->n_redirects >= ip_rt_redirect_number) { 909 peer->rate_last = jiffies; 910 goto out_put_peer; 911 } 912 913 /* Check for load limit; set rate_last to the latest sent 914 * redirect. 915 */ 916 if (peer->rate_tokens == 0 || 917 time_after(jiffies, 918 (peer->rate_last + 919 (ip_rt_redirect_load << peer->rate_tokens)))) { 920 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 921 922 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 923 peer->rate_last = jiffies; 924 ++peer->rate_tokens; 925 ++peer->n_redirects; 926 #ifdef CONFIG_IP_ROUTE_VERBOSE 927 if (log_martians && 928 peer->rate_tokens == ip_rt_redirect_number) 929 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 930 &ip_hdr(skb)->saddr, inet_iif(skb), 931 &ip_hdr(skb)->daddr, &gw); 932 #endif 933 } 934 out_put_peer: 935 inet_putpeer(peer); 936 } 937 938 static int ip_error(struct sk_buff *skb) 939 { 940 struct rtable *rt = skb_rtable(skb); 941 struct net_device *dev = skb->dev; 942 struct in_device *in_dev; 943 struct inet_peer *peer; 944 unsigned long now; 945 struct net *net; 946 bool send; 947 int code; 948 949 if (netif_is_l3_master(skb->dev)) { 950 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 951 if (!dev) 952 goto out; 953 } 954 955 in_dev = __in_dev_get_rcu(dev); 956 957 /* IP on this device is disabled. */ 958 if (!in_dev) 959 goto out; 960 961 net = dev_net(rt->dst.dev); 962 if (!IN_DEV_FORWARD(in_dev)) { 963 switch (rt->dst.error) { 964 case EHOSTUNREACH: 965 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 966 break; 967 968 case ENETUNREACH: 969 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 970 break; 971 } 972 goto out; 973 } 974 975 switch (rt->dst.error) { 976 case EINVAL: 977 default: 978 goto out; 979 case EHOSTUNREACH: 980 code = ICMP_HOST_UNREACH; 981 break; 982 case ENETUNREACH: 983 code = ICMP_NET_UNREACH; 984 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 985 break; 986 case EACCES: 987 code = ICMP_PKT_FILTERED; 988 break; 989 } 990 991 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 992 l3mdev_master_ifindex(skb->dev), 1); 993 994 send = true; 995 if (peer) { 996 now = jiffies; 997 peer->rate_tokens += now - peer->rate_last; 998 if (peer->rate_tokens > ip_rt_error_burst) 999 peer->rate_tokens = ip_rt_error_burst; 1000 peer->rate_last = now; 1001 if (peer->rate_tokens >= ip_rt_error_cost) 1002 peer->rate_tokens -= ip_rt_error_cost; 1003 else 1004 send = false; 1005 inet_putpeer(peer); 1006 } 1007 if (send) 1008 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1009 1010 out: kfree_skb(skb); 1011 return 0; 1012 } 1013 1014 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1015 { 1016 struct dst_entry *dst = &rt->dst; 1017 u32 old_mtu = ipv4_mtu(dst); 1018 struct fib_result res; 1019 bool lock = false; 1020 1021 if (ip_mtu_locked(dst)) 1022 return; 1023 1024 if (old_mtu < mtu) 1025 return; 1026 1027 if (mtu < ip_rt_min_pmtu) { 1028 lock = true; 1029 mtu = min(old_mtu, ip_rt_min_pmtu); 1030 } 1031 1032 if (rt->rt_pmtu == mtu && !lock && 1033 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1034 return; 1035 1036 rcu_read_lock(); 1037 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1038 struct fib_nh_common *nhc = FIB_RES_NHC(res); 1039 1040 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1041 jiffies + ip_rt_mtu_expires); 1042 } 1043 rcu_read_unlock(); 1044 } 1045 1046 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1047 struct sk_buff *skb, u32 mtu) 1048 { 1049 struct rtable *rt = (struct rtable *) dst; 1050 struct flowi4 fl4; 1051 1052 ip_rt_build_flow_key(&fl4, sk, skb); 1053 __ip_rt_update_pmtu(rt, &fl4, mtu); 1054 } 1055 1056 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1057 int oif, u8 protocol) 1058 { 1059 const struct iphdr *iph = (const struct iphdr *) skb->data; 1060 struct flowi4 fl4; 1061 struct rtable *rt; 1062 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1063 1064 __build_flow_key(net, &fl4, NULL, iph, oif, 1065 RT_TOS(iph->tos), protocol, mark, 0); 1066 rt = __ip_route_output_key(net, &fl4); 1067 if (!IS_ERR(rt)) { 1068 __ip_rt_update_pmtu(rt, &fl4, mtu); 1069 ip_rt_put(rt); 1070 } 1071 } 1072 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1073 1074 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1075 { 1076 const struct iphdr *iph = (const struct iphdr *) skb->data; 1077 struct flowi4 fl4; 1078 struct rtable *rt; 1079 1080 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1081 1082 if (!fl4.flowi4_mark) 1083 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1084 1085 rt = __ip_route_output_key(sock_net(sk), &fl4); 1086 if (!IS_ERR(rt)) { 1087 __ip_rt_update_pmtu(rt, &fl4, mtu); 1088 ip_rt_put(rt); 1089 } 1090 } 1091 1092 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1093 { 1094 const struct iphdr *iph = (const struct iphdr *) skb->data; 1095 struct flowi4 fl4; 1096 struct rtable *rt; 1097 struct dst_entry *odst = NULL; 1098 bool new = false; 1099 struct net *net = sock_net(sk); 1100 1101 bh_lock_sock(sk); 1102 1103 if (!ip_sk_accept_pmtu(sk)) 1104 goto out; 1105 1106 odst = sk_dst_get(sk); 1107 1108 if (sock_owned_by_user(sk) || !odst) { 1109 __ipv4_sk_update_pmtu(skb, sk, mtu); 1110 goto out; 1111 } 1112 1113 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1114 1115 rt = (struct rtable *)odst; 1116 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1117 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1118 if (IS_ERR(rt)) 1119 goto out; 1120 1121 new = true; 1122 } 1123 1124 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1125 1126 if (!dst_check(&rt->dst, 0)) { 1127 if (new) 1128 dst_release(&rt->dst); 1129 1130 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1131 if (IS_ERR(rt)) 1132 goto out; 1133 1134 new = true; 1135 } 1136 1137 if (new) 1138 sk_dst_set(sk, &rt->dst); 1139 1140 out: 1141 bh_unlock_sock(sk); 1142 dst_release(odst); 1143 } 1144 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1145 1146 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1147 int oif, u8 protocol) 1148 { 1149 const struct iphdr *iph = (const struct iphdr *) skb->data; 1150 struct flowi4 fl4; 1151 struct rtable *rt; 1152 1153 __build_flow_key(net, &fl4, NULL, iph, oif, 1154 RT_TOS(iph->tos), protocol, 0, 0); 1155 rt = __ip_route_output_key(net, &fl4); 1156 if (!IS_ERR(rt)) { 1157 __ip_do_redirect(rt, skb, &fl4, false); 1158 ip_rt_put(rt); 1159 } 1160 } 1161 EXPORT_SYMBOL_GPL(ipv4_redirect); 1162 1163 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1164 { 1165 const struct iphdr *iph = (const struct iphdr *) skb->data; 1166 struct flowi4 fl4; 1167 struct rtable *rt; 1168 struct net *net = sock_net(sk); 1169 1170 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1171 rt = __ip_route_output_key(net, &fl4); 1172 if (!IS_ERR(rt)) { 1173 __ip_do_redirect(rt, skb, &fl4, false); 1174 ip_rt_put(rt); 1175 } 1176 } 1177 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1178 1179 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1180 { 1181 struct rtable *rt = (struct rtable *) dst; 1182 1183 /* All IPV4 dsts are created with ->obsolete set to the value 1184 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1185 * into this function always. 1186 * 1187 * When a PMTU/redirect information update invalidates a route, 1188 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1189 * DST_OBSOLETE_DEAD. 1190 */ 1191 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1192 return NULL; 1193 return dst; 1194 } 1195 1196 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1197 { 1198 struct ip_options opt; 1199 int res; 1200 1201 /* Recompile ip options since IPCB may not be valid anymore. 1202 * Also check we have a reasonable ipv4 header. 1203 */ 1204 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1205 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1206 return; 1207 1208 memset(&opt, 0, sizeof(opt)); 1209 if (ip_hdr(skb)->ihl > 5) { 1210 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1211 return; 1212 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1213 1214 rcu_read_lock(); 1215 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1216 rcu_read_unlock(); 1217 1218 if (res) 1219 return; 1220 } 1221 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1222 } 1223 1224 static void ipv4_link_failure(struct sk_buff *skb) 1225 { 1226 struct rtable *rt; 1227 1228 ipv4_send_dest_unreach(skb); 1229 1230 rt = skb_rtable(skb); 1231 if (rt) 1232 dst_set_expires(&rt->dst, 0); 1233 } 1234 1235 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1236 { 1237 pr_debug("%s: %pI4 -> %pI4, %s\n", 1238 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1239 skb->dev ? skb->dev->name : "?"); 1240 kfree_skb(skb); 1241 WARN_ON(1); 1242 return 0; 1243 } 1244 1245 /* 1246 We do not cache source address of outgoing interface, 1247 because it is used only by IP RR, TS and SRR options, 1248 so that it out of fast path. 1249 1250 BTW remember: "addr" is allowed to be not aligned 1251 in IP options! 1252 */ 1253 1254 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1255 { 1256 __be32 src; 1257 1258 if (rt_is_output_route(rt)) 1259 src = ip_hdr(skb)->saddr; 1260 else { 1261 struct fib_result res; 1262 struct iphdr *iph = ip_hdr(skb); 1263 struct flowi4 fl4 = { 1264 .daddr = iph->daddr, 1265 .saddr = iph->saddr, 1266 .flowi4_tos = RT_TOS(iph->tos), 1267 .flowi4_oif = rt->dst.dev->ifindex, 1268 .flowi4_iif = skb->dev->ifindex, 1269 .flowi4_mark = skb->mark, 1270 }; 1271 1272 rcu_read_lock(); 1273 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1274 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1275 else 1276 src = inet_select_addr(rt->dst.dev, 1277 rt_nexthop(rt, iph->daddr), 1278 RT_SCOPE_UNIVERSE); 1279 rcu_read_unlock(); 1280 } 1281 memcpy(addr, &src, 4); 1282 } 1283 1284 #ifdef CONFIG_IP_ROUTE_CLASSID 1285 static void set_class_tag(struct rtable *rt, u32 tag) 1286 { 1287 if (!(rt->dst.tclassid & 0xFFFF)) 1288 rt->dst.tclassid |= tag & 0xFFFF; 1289 if (!(rt->dst.tclassid & 0xFFFF0000)) 1290 rt->dst.tclassid |= tag & 0xFFFF0000; 1291 } 1292 #endif 1293 1294 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1295 { 1296 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1297 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1298 ip_rt_min_advmss); 1299 1300 return min(advmss, IPV4_MAX_PMTU - header_size); 1301 } 1302 1303 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1304 { 1305 const struct rtable *rt = (const struct rtable *) dst; 1306 unsigned int mtu = rt->rt_pmtu; 1307 1308 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1309 mtu = dst_metric_raw(dst, RTAX_MTU); 1310 1311 if (mtu) 1312 return mtu; 1313 1314 mtu = READ_ONCE(dst->dev->mtu); 1315 1316 if (unlikely(ip_mtu_locked(dst))) { 1317 if (rt->rt_uses_gateway && mtu > 576) 1318 mtu = 576; 1319 } 1320 1321 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1322 1323 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1324 } 1325 1326 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1327 { 1328 struct fnhe_hash_bucket *hash; 1329 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1330 u32 hval = fnhe_hashfun(daddr); 1331 1332 spin_lock_bh(&fnhe_lock); 1333 1334 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1335 lockdep_is_held(&fnhe_lock)); 1336 hash += hval; 1337 1338 fnhe_p = &hash->chain; 1339 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1340 while (fnhe) { 1341 if (fnhe->fnhe_daddr == daddr) { 1342 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1343 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1344 /* set fnhe_daddr to 0 to ensure it won't bind with 1345 * new dsts in rt_bind_exception(). 1346 */ 1347 fnhe->fnhe_daddr = 0; 1348 fnhe_flush_routes(fnhe); 1349 kfree_rcu(fnhe, rcu); 1350 break; 1351 } 1352 fnhe_p = &fnhe->fnhe_next; 1353 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1354 lockdep_is_held(&fnhe_lock)); 1355 } 1356 1357 spin_unlock_bh(&fnhe_lock); 1358 } 1359 1360 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1361 __be32 daddr) 1362 { 1363 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1364 struct fib_nh_exception *fnhe; 1365 u32 hval; 1366 1367 if (!hash) 1368 return NULL; 1369 1370 hval = fnhe_hashfun(daddr); 1371 1372 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1373 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1374 if (fnhe->fnhe_daddr == daddr) { 1375 if (fnhe->fnhe_expires && 1376 time_after(jiffies, fnhe->fnhe_expires)) { 1377 ip_del_fnhe(nhc, daddr); 1378 break; 1379 } 1380 return fnhe; 1381 } 1382 } 1383 return NULL; 1384 } 1385 1386 /* MTU selection: 1387 * 1. mtu on route is locked - use it 1388 * 2. mtu from nexthop exception 1389 * 3. mtu from egress device 1390 */ 1391 1392 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1393 { 1394 struct fib_nh_common *nhc = res->nhc; 1395 struct net_device *dev = nhc->nhc_dev; 1396 struct fib_info *fi = res->fi; 1397 u32 mtu = 0; 1398 1399 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1400 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1401 mtu = fi->fib_mtu; 1402 1403 if (likely(!mtu)) { 1404 struct fib_nh_exception *fnhe; 1405 1406 fnhe = find_exception(nhc, daddr); 1407 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1408 mtu = fnhe->fnhe_pmtu; 1409 } 1410 1411 if (likely(!mtu)) 1412 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1413 1414 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1415 } 1416 1417 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1418 __be32 daddr, const bool do_cache) 1419 { 1420 bool ret = false; 1421 1422 spin_lock_bh(&fnhe_lock); 1423 1424 if (daddr == fnhe->fnhe_daddr) { 1425 struct rtable __rcu **porig; 1426 struct rtable *orig; 1427 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1428 1429 if (rt_is_input_route(rt)) 1430 porig = &fnhe->fnhe_rth_input; 1431 else 1432 porig = &fnhe->fnhe_rth_output; 1433 orig = rcu_dereference(*porig); 1434 1435 if (fnhe->fnhe_genid != genid) { 1436 fnhe->fnhe_genid = genid; 1437 fnhe->fnhe_gw = 0; 1438 fnhe->fnhe_pmtu = 0; 1439 fnhe->fnhe_expires = 0; 1440 fnhe->fnhe_mtu_locked = false; 1441 fnhe_flush_routes(fnhe); 1442 orig = NULL; 1443 } 1444 fill_route_from_fnhe(rt, fnhe); 1445 if (!rt->rt_gw4) { 1446 rt->rt_gw4 = daddr; 1447 rt->rt_gw_family = AF_INET; 1448 } 1449 1450 if (do_cache) { 1451 dst_hold(&rt->dst); 1452 rcu_assign_pointer(*porig, rt); 1453 if (orig) { 1454 dst_dev_put(&orig->dst); 1455 dst_release(&orig->dst); 1456 } 1457 ret = true; 1458 } 1459 1460 fnhe->fnhe_stamp = jiffies; 1461 } 1462 spin_unlock_bh(&fnhe_lock); 1463 1464 return ret; 1465 } 1466 1467 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1468 { 1469 struct rtable *orig, *prev, **p; 1470 bool ret = true; 1471 1472 if (rt_is_input_route(rt)) { 1473 p = (struct rtable **)&nhc->nhc_rth_input; 1474 } else { 1475 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1476 } 1477 orig = *p; 1478 1479 /* hold dst before doing cmpxchg() to avoid race condition 1480 * on this dst 1481 */ 1482 dst_hold(&rt->dst); 1483 prev = cmpxchg(p, orig, rt); 1484 if (prev == orig) { 1485 if (orig) { 1486 dst_dev_put(&orig->dst); 1487 dst_release(&orig->dst); 1488 } 1489 } else { 1490 dst_release(&rt->dst); 1491 ret = false; 1492 } 1493 1494 return ret; 1495 } 1496 1497 struct uncached_list { 1498 spinlock_t lock; 1499 struct list_head head; 1500 }; 1501 1502 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1503 1504 void rt_add_uncached_list(struct rtable *rt) 1505 { 1506 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1507 1508 rt->rt_uncached_list = ul; 1509 1510 spin_lock_bh(&ul->lock); 1511 list_add_tail(&rt->rt_uncached, &ul->head); 1512 spin_unlock_bh(&ul->lock); 1513 } 1514 1515 void rt_del_uncached_list(struct rtable *rt) 1516 { 1517 if (!list_empty(&rt->rt_uncached)) { 1518 struct uncached_list *ul = rt->rt_uncached_list; 1519 1520 spin_lock_bh(&ul->lock); 1521 list_del(&rt->rt_uncached); 1522 spin_unlock_bh(&ul->lock); 1523 } 1524 } 1525 1526 static void ipv4_dst_destroy(struct dst_entry *dst) 1527 { 1528 struct rtable *rt = (struct rtable *)dst; 1529 1530 ip_dst_metrics_put(dst); 1531 rt_del_uncached_list(rt); 1532 } 1533 1534 void rt_flush_dev(struct net_device *dev) 1535 { 1536 struct rtable *rt; 1537 int cpu; 1538 1539 for_each_possible_cpu(cpu) { 1540 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1541 1542 spin_lock_bh(&ul->lock); 1543 list_for_each_entry(rt, &ul->head, rt_uncached) { 1544 if (rt->dst.dev != dev) 1545 continue; 1546 rt->dst.dev = blackhole_netdev; 1547 dev_hold(rt->dst.dev); 1548 dev_put(dev); 1549 } 1550 spin_unlock_bh(&ul->lock); 1551 } 1552 } 1553 1554 static bool rt_cache_valid(const struct rtable *rt) 1555 { 1556 return rt && 1557 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1558 !rt_is_expired(rt); 1559 } 1560 1561 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1562 const struct fib_result *res, 1563 struct fib_nh_exception *fnhe, 1564 struct fib_info *fi, u16 type, u32 itag, 1565 const bool do_cache) 1566 { 1567 bool cached = false; 1568 1569 if (fi) { 1570 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1571 1572 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1573 rt->rt_uses_gateway = 1; 1574 rt->rt_gw_family = nhc->nhc_gw_family; 1575 /* only INET and INET6 are supported */ 1576 if (likely(nhc->nhc_gw_family == AF_INET)) 1577 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1578 else 1579 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1580 } 1581 1582 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1583 1584 #ifdef CONFIG_IP_ROUTE_CLASSID 1585 if (nhc->nhc_family == AF_INET) { 1586 struct fib_nh *nh; 1587 1588 nh = container_of(nhc, struct fib_nh, nh_common); 1589 rt->dst.tclassid = nh->nh_tclassid; 1590 } 1591 #endif 1592 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1593 if (unlikely(fnhe)) 1594 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1595 else if (do_cache) 1596 cached = rt_cache_route(nhc, rt); 1597 if (unlikely(!cached)) { 1598 /* Routes we intend to cache in nexthop exception or 1599 * FIB nexthop have the DST_NOCACHE bit clear. 1600 * However, if we are unsuccessful at storing this 1601 * route into the cache we really need to set it. 1602 */ 1603 if (!rt->rt_gw4) { 1604 rt->rt_gw_family = AF_INET; 1605 rt->rt_gw4 = daddr; 1606 } 1607 rt_add_uncached_list(rt); 1608 } 1609 } else 1610 rt_add_uncached_list(rt); 1611 1612 #ifdef CONFIG_IP_ROUTE_CLASSID 1613 #ifdef CONFIG_IP_MULTIPLE_TABLES 1614 set_class_tag(rt, res->tclassid); 1615 #endif 1616 set_class_tag(rt, itag); 1617 #endif 1618 } 1619 1620 struct rtable *rt_dst_alloc(struct net_device *dev, 1621 unsigned int flags, u16 type, 1622 bool nopolicy, bool noxfrm, bool will_cache) 1623 { 1624 struct rtable *rt; 1625 1626 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1627 (will_cache ? 0 : DST_HOST) | 1628 (nopolicy ? DST_NOPOLICY : 0) | 1629 (noxfrm ? DST_NOXFRM : 0)); 1630 1631 if (rt) { 1632 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1633 rt->rt_flags = flags; 1634 rt->rt_type = type; 1635 rt->rt_is_input = 0; 1636 rt->rt_iif = 0; 1637 rt->rt_pmtu = 0; 1638 rt->rt_mtu_locked = 0; 1639 rt->rt_uses_gateway = 0; 1640 rt->rt_gw_family = 0; 1641 rt->rt_gw4 = 0; 1642 INIT_LIST_HEAD(&rt->rt_uncached); 1643 1644 rt->dst.output = ip_output; 1645 if (flags & RTCF_LOCAL) 1646 rt->dst.input = ip_local_deliver; 1647 } 1648 1649 return rt; 1650 } 1651 EXPORT_SYMBOL(rt_dst_alloc); 1652 1653 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1654 { 1655 struct rtable *new_rt; 1656 1657 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1658 rt->dst.flags); 1659 1660 if (new_rt) { 1661 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1662 new_rt->rt_flags = rt->rt_flags; 1663 new_rt->rt_type = rt->rt_type; 1664 new_rt->rt_is_input = rt->rt_is_input; 1665 new_rt->rt_iif = rt->rt_iif; 1666 new_rt->rt_pmtu = rt->rt_pmtu; 1667 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1668 new_rt->rt_gw_family = rt->rt_gw_family; 1669 if (rt->rt_gw_family == AF_INET) 1670 new_rt->rt_gw4 = rt->rt_gw4; 1671 else if (rt->rt_gw_family == AF_INET6) 1672 new_rt->rt_gw6 = rt->rt_gw6; 1673 INIT_LIST_HEAD(&new_rt->rt_uncached); 1674 1675 new_rt->dst.flags |= DST_HOST; 1676 new_rt->dst.input = rt->dst.input; 1677 new_rt->dst.output = rt->dst.output; 1678 new_rt->dst.error = rt->dst.error; 1679 new_rt->dst.lastuse = jiffies; 1680 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1681 } 1682 return new_rt; 1683 } 1684 EXPORT_SYMBOL(rt_dst_clone); 1685 1686 /* called in rcu_read_lock() section */ 1687 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1688 u8 tos, struct net_device *dev, 1689 struct in_device *in_dev, u32 *itag) 1690 { 1691 int err; 1692 1693 /* Primary sanity checks. */ 1694 if (!in_dev) 1695 return -EINVAL; 1696 1697 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1698 skb->protocol != htons(ETH_P_IP)) 1699 return -EINVAL; 1700 1701 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1702 return -EINVAL; 1703 1704 if (ipv4_is_zeronet(saddr)) { 1705 if (!ipv4_is_local_multicast(daddr) && 1706 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1707 return -EINVAL; 1708 } else { 1709 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1710 in_dev, itag); 1711 if (err < 0) 1712 return err; 1713 } 1714 return 0; 1715 } 1716 1717 /* called in rcu_read_lock() section */ 1718 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1719 u8 tos, struct net_device *dev, int our) 1720 { 1721 struct in_device *in_dev = __in_dev_get_rcu(dev); 1722 unsigned int flags = RTCF_MULTICAST; 1723 struct rtable *rth; 1724 u32 itag = 0; 1725 int err; 1726 1727 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1728 if (err) 1729 return err; 1730 1731 if (our) 1732 flags |= RTCF_LOCAL; 1733 1734 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1735 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1736 if (!rth) 1737 return -ENOBUFS; 1738 1739 #ifdef CONFIG_IP_ROUTE_CLASSID 1740 rth->dst.tclassid = itag; 1741 #endif 1742 rth->dst.output = ip_rt_bug; 1743 rth->rt_is_input= 1; 1744 1745 #ifdef CONFIG_IP_MROUTE 1746 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1747 rth->dst.input = ip_mr_input; 1748 #endif 1749 RT_CACHE_STAT_INC(in_slow_mc); 1750 1751 skb_dst_set(skb, &rth->dst); 1752 return 0; 1753 } 1754 1755 1756 static void ip_handle_martian_source(struct net_device *dev, 1757 struct in_device *in_dev, 1758 struct sk_buff *skb, 1759 __be32 daddr, 1760 __be32 saddr) 1761 { 1762 RT_CACHE_STAT_INC(in_martian_src); 1763 #ifdef CONFIG_IP_ROUTE_VERBOSE 1764 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1765 /* 1766 * RFC1812 recommendation, if source is martian, 1767 * the only hint is MAC header. 1768 */ 1769 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1770 &daddr, &saddr, dev->name); 1771 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1772 print_hex_dump(KERN_WARNING, "ll header: ", 1773 DUMP_PREFIX_OFFSET, 16, 1, 1774 skb_mac_header(skb), 1775 dev->hard_header_len, false); 1776 } 1777 } 1778 #endif 1779 } 1780 1781 /* called in rcu_read_lock() section */ 1782 static int __mkroute_input(struct sk_buff *skb, 1783 const struct fib_result *res, 1784 struct in_device *in_dev, 1785 __be32 daddr, __be32 saddr, u32 tos) 1786 { 1787 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1788 struct net_device *dev = nhc->nhc_dev; 1789 struct fib_nh_exception *fnhe; 1790 struct rtable *rth; 1791 int err; 1792 struct in_device *out_dev; 1793 bool do_cache; 1794 u32 itag = 0; 1795 1796 /* get a working reference to the output device */ 1797 out_dev = __in_dev_get_rcu(dev); 1798 if (!out_dev) { 1799 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1800 return -EINVAL; 1801 } 1802 1803 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1804 in_dev->dev, in_dev, &itag); 1805 if (err < 0) { 1806 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1807 saddr); 1808 1809 goto cleanup; 1810 } 1811 1812 do_cache = res->fi && !itag; 1813 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1814 skb->protocol == htons(ETH_P_IP)) { 1815 __be32 gw; 1816 1817 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1818 if (IN_DEV_SHARED_MEDIA(out_dev) || 1819 inet_addr_onlink(out_dev, saddr, gw)) 1820 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1821 } 1822 1823 if (skb->protocol != htons(ETH_P_IP)) { 1824 /* Not IP (i.e. ARP). Do not create route, if it is 1825 * invalid for proxy arp. DNAT routes are always valid. 1826 * 1827 * Proxy arp feature have been extended to allow, ARP 1828 * replies back to the same interface, to support 1829 * Private VLAN switch technologies. See arp.c. 1830 */ 1831 if (out_dev == in_dev && 1832 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1833 err = -EINVAL; 1834 goto cleanup; 1835 } 1836 } 1837 1838 fnhe = find_exception(nhc, daddr); 1839 if (do_cache) { 1840 if (fnhe) 1841 rth = rcu_dereference(fnhe->fnhe_rth_input); 1842 else 1843 rth = rcu_dereference(nhc->nhc_rth_input); 1844 if (rt_cache_valid(rth)) { 1845 skb_dst_set_noref(skb, &rth->dst); 1846 goto out; 1847 } 1848 } 1849 1850 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1851 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1852 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1853 if (!rth) { 1854 err = -ENOBUFS; 1855 goto cleanup; 1856 } 1857 1858 rth->rt_is_input = 1; 1859 RT_CACHE_STAT_INC(in_slow_tot); 1860 1861 rth->dst.input = ip_forward; 1862 1863 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1864 do_cache); 1865 lwtunnel_set_redirect(&rth->dst); 1866 skb_dst_set(skb, &rth->dst); 1867 out: 1868 err = 0; 1869 cleanup: 1870 return err; 1871 } 1872 1873 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1874 /* To make ICMP packets follow the right flow, the multipath hash is 1875 * calculated from the inner IP addresses. 1876 */ 1877 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1878 struct flow_keys *hash_keys) 1879 { 1880 const struct iphdr *outer_iph = ip_hdr(skb); 1881 const struct iphdr *key_iph = outer_iph; 1882 const struct iphdr *inner_iph; 1883 const struct icmphdr *icmph; 1884 struct iphdr _inner_iph; 1885 struct icmphdr _icmph; 1886 1887 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1888 goto out; 1889 1890 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1891 goto out; 1892 1893 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1894 &_icmph); 1895 if (!icmph) 1896 goto out; 1897 1898 if (icmph->type != ICMP_DEST_UNREACH && 1899 icmph->type != ICMP_REDIRECT && 1900 icmph->type != ICMP_TIME_EXCEEDED && 1901 icmph->type != ICMP_PARAMETERPROB) 1902 goto out; 1903 1904 inner_iph = skb_header_pointer(skb, 1905 outer_iph->ihl * 4 + sizeof(_icmph), 1906 sizeof(_inner_iph), &_inner_iph); 1907 if (!inner_iph) 1908 goto out; 1909 1910 key_iph = inner_iph; 1911 out: 1912 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1913 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1914 } 1915 1916 /* if skb is set it will be used and fl4 can be NULL */ 1917 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1918 const struct sk_buff *skb, struct flow_keys *flkeys) 1919 { 1920 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1921 struct flow_keys hash_keys; 1922 u32 mhash; 1923 1924 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1925 case 0: 1926 memset(&hash_keys, 0, sizeof(hash_keys)); 1927 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1928 if (skb) { 1929 ip_multipath_l3_keys(skb, &hash_keys); 1930 } else { 1931 hash_keys.addrs.v4addrs.src = fl4->saddr; 1932 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1933 } 1934 break; 1935 case 1: 1936 /* skb is currently provided only when forwarding */ 1937 if (skb) { 1938 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1939 struct flow_keys keys; 1940 1941 /* short-circuit if we already have L4 hash present */ 1942 if (skb->l4_hash) 1943 return skb_get_hash_raw(skb) >> 1; 1944 1945 memset(&hash_keys, 0, sizeof(hash_keys)); 1946 1947 if (!flkeys) { 1948 skb_flow_dissect_flow_keys(skb, &keys, flag); 1949 flkeys = &keys; 1950 } 1951 1952 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1953 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1954 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1955 hash_keys.ports.src = flkeys->ports.src; 1956 hash_keys.ports.dst = flkeys->ports.dst; 1957 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1958 } else { 1959 memset(&hash_keys, 0, sizeof(hash_keys)); 1960 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1961 hash_keys.addrs.v4addrs.src = fl4->saddr; 1962 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1963 hash_keys.ports.src = fl4->fl4_sport; 1964 hash_keys.ports.dst = fl4->fl4_dport; 1965 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1966 } 1967 break; 1968 case 2: 1969 memset(&hash_keys, 0, sizeof(hash_keys)); 1970 /* skb is currently provided only when forwarding */ 1971 if (skb) { 1972 struct flow_keys keys; 1973 1974 skb_flow_dissect_flow_keys(skb, &keys, 0); 1975 /* Inner can be v4 or v6 */ 1976 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1977 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1978 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1979 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1980 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1981 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1982 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1983 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1984 hash_keys.tags.flow_label = keys.tags.flow_label; 1985 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1986 } else { 1987 /* Same as case 0 */ 1988 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1989 ip_multipath_l3_keys(skb, &hash_keys); 1990 } 1991 } else { 1992 /* Same as case 0 */ 1993 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1994 hash_keys.addrs.v4addrs.src = fl4->saddr; 1995 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1996 } 1997 break; 1998 } 1999 mhash = flow_hash_from_keys(&hash_keys); 2000 2001 if (multipath_hash) 2002 mhash = jhash_2words(mhash, multipath_hash, 0); 2003 2004 return mhash >> 1; 2005 } 2006 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2007 2008 static int ip_mkroute_input(struct sk_buff *skb, 2009 struct fib_result *res, 2010 struct in_device *in_dev, 2011 __be32 daddr, __be32 saddr, u32 tos, 2012 struct flow_keys *hkeys) 2013 { 2014 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2015 if (res->fi && fib_info_num_path(res->fi) > 1) { 2016 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2017 2018 fib_select_multipath(res, h); 2019 } 2020 #endif 2021 2022 /* create a routing cache entry */ 2023 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2024 } 2025 2026 /* 2027 * NOTE. We drop all the packets that has local source 2028 * addresses, because every properly looped back packet 2029 * must have correct destination already attached by output routine. 2030 * 2031 * Such approach solves two big problems: 2032 * 1. Not simplex devices are handled properly. 2033 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2034 * called with rcu_read_lock() 2035 */ 2036 2037 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2038 u8 tos, struct net_device *dev, 2039 struct fib_result *res) 2040 { 2041 struct in_device *in_dev = __in_dev_get_rcu(dev); 2042 struct flow_keys *flkeys = NULL, _flkeys; 2043 struct net *net = dev_net(dev); 2044 struct ip_tunnel_info *tun_info; 2045 int err = -EINVAL; 2046 unsigned int flags = 0; 2047 u32 itag = 0; 2048 struct rtable *rth; 2049 struct flowi4 fl4; 2050 bool do_cache = true; 2051 2052 /* IP on this device is disabled. */ 2053 2054 if (!in_dev) 2055 goto out; 2056 2057 /* Check for the most weird martians, which can be not detected 2058 by fib_lookup. 2059 */ 2060 2061 tun_info = skb_tunnel_info(skb); 2062 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2063 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2064 else 2065 fl4.flowi4_tun_key.tun_id = 0; 2066 skb_dst_drop(skb); 2067 2068 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2069 goto martian_source; 2070 2071 res->fi = NULL; 2072 res->table = NULL; 2073 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2074 goto brd_input; 2075 2076 /* Accept zero addresses only to limited broadcast; 2077 * I even do not know to fix it or not. Waiting for complains :-) 2078 */ 2079 if (ipv4_is_zeronet(saddr)) 2080 goto martian_source; 2081 2082 if (ipv4_is_zeronet(daddr)) 2083 goto martian_destination; 2084 2085 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2086 * and call it once if daddr or/and saddr are loopback addresses 2087 */ 2088 if (ipv4_is_loopback(daddr)) { 2089 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2090 goto martian_destination; 2091 } else if (ipv4_is_loopback(saddr)) { 2092 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2093 goto martian_source; 2094 } 2095 2096 /* 2097 * Now we are ready to route packet. 2098 */ 2099 fl4.flowi4_oif = 0; 2100 fl4.flowi4_iif = dev->ifindex; 2101 fl4.flowi4_mark = skb->mark; 2102 fl4.flowi4_tos = tos; 2103 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2104 fl4.flowi4_flags = 0; 2105 fl4.daddr = daddr; 2106 fl4.saddr = saddr; 2107 fl4.flowi4_uid = sock_net_uid(net, NULL); 2108 2109 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2110 flkeys = &_flkeys; 2111 } else { 2112 fl4.flowi4_proto = 0; 2113 fl4.fl4_sport = 0; 2114 fl4.fl4_dport = 0; 2115 } 2116 2117 err = fib_lookup(net, &fl4, res, 0); 2118 if (err != 0) { 2119 if (!IN_DEV_FORWARD(in_dev)) 2120 err = -EHOSTUNREACH; 2121 goto no_route; 2122 } 2123 2124 if (res->type == RTN_BROADCAST) { 2125 if (IN_DEV_BFORWARD(in_dev)) 2126 goto make_route; 2127 /* not do cache if bc_forwarding is enabled */ 2128 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2129 do_cache = false; 2130 goto brd_input; 2131 } 2132 2133 if (res->type == RTN_LOCAL) { 2134 err = fib_validate_source(skb, saddr, daddr, tos, 2135 0, dev, in_dev, &itag); 2136 if (err < 0) 2137 goto martian_source; 2138 goto local_input; 2139 } 2140 2141 if (!IN_DEV_FORWARD(in_dev)) { 2142 err = -EHOSTUNREACH; 2143 goto no_route; 2144 } 2145 if (res->type != RTN_UNICAST) 2146 goto martian_destination; 2147 2148 make_route: 2149 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2150 out: return err; 2151 2152 brd_input: 2153 if (skb->protocol != htons(ETH_P_IP)) 2154 goto e_inval; 2155 2156 if (!ipv4_is_zeronet(saddr)) { 2157 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2158 in_dev, &itag); 2159 if (err < 0) 2160 goto martian_source; 2161 } 2162 flags |= RTCF_BROADCAST; 2163 res->type = RTN_BROADCAST; 2164 RT_CACHE_STAT_INC(in_brd); 2165 2166 local_input: 2167 do_cache &= res->fi && !itag; 2168 if (do_cache) { 2169 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2170 2171 rth = rcu_dereference(nhc->nhc_rth_input); 2172 if (rt_cache_valid(rth)) { 2173 skb_dst_set_noref(skb, &rth->dst); 2174 err = 0; 2175 goto out; 2176 } 2177 } 2178 2179 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2180 flags | RTCF_LOCAL, res->type, 2181 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2182 if (!rth) 2183 goto e_nobufs; 2184 2185 rth->dst.output= ip_rt_bug; 2186 #ifdef CONFIG_IP_ROUTE_CLASSID 2187 rth->dst.tclassid = itag; 2188 #endif 2189 rth->rt_is_input = 1; 2190 2191 RT_CACHE_STAT_INC(in_slow_tot); 2192 if (res->type == RTN_UNREACHABLE) { 2193 rth->dst.input= ip_error; 2194 rth->dst.error= -err; 2195 rth->rt_flags &= ~RTCF_LOCAL; 2196 } 2197 2198 if (do_cache) { 2199 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2200 2201 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2202 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2203 WARN_ON(rth->dst.input == lwtunnel_input); 2204 rth->dst.lwtstate->orig_input = rth->dst.input; 2205 rth->dst.input = lwtunnel_input; 2206 } 2207 2208 if (unlikely(!rt_cache_route(nhc, rth))) 2209 rt_add_uncached_list(rth); 2210 } 2211 skb_dst_set(skb, &rth->dst); 2212 err = 0; 2213 goto out; 2214 2215 no_route: 2216 RT_CACHE_STAT_INC(in_no_route); 2217 res->type = RTN_UNREACHABLE; 2218 res->fi = NULL; 2219 res->table = NULL; 2220 goto local_input; 2221 2222 /* 2223 * Do not cache martian addresses: they should be logged (RFC1812) 2224 */ 2225 martian_destination: 2226 RT_CACHE_STAT_INC(in_martian_dst); 2227 #ifdef CONFIG_IP_ROUTE_VERBOSE 2228 if (IN_DEV_LOG_MARTIANS(in_dev)) 2229 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2230 &daddr, &saddr, dev->name); 2231 #endif 2232 2233 e_inval: 2234 err = -EINVAL; 2235 goto out; 2236 2237 e_nobufs: 2238 err = -ENOBUFS; 2239 goto out; 2240 2241 martian_source: 2242 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2243 goto out; 2244 } 2245 2246 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2247 u8 tos, struct net_device *dev) 2248 { 2249 struct fib_result res; 2250 int err; 2251 2252 tos &= IPTOS_RT_MASK; 2253 rcu_read_lock(); 2254 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2255 rcu_read_unlock(); 2256 2257 return err; 2258 } 2259 EXPORT_SYMBOL(ip_route_input_noref); 2260 2261 /* called with rcu_read_lock held */ 2262 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2263 u8 tos, struct net_device *dev, struct fib_result *res) 2264 { 2265 /* Multicast recognition logic is moved from route cache to here. 2266 The problem was that too many Ethernet cards have broken/missing 2267 hardware multicast filters :-( As result the host on multicasting 2268 network acquires a lot of useless route cache entries, sort of 2269 SDR messages from all the world. Now we try to get rid of them. 2270 Really, provided software IP multicast filter is organized 2271 reasonably (at least, hashed), it does not result in a slowdown 2272 comparing with route cache reject entries. 2273 Note, that multicast routers are not affected, because 2274 route cache entry is created eventually. 2275 */ 2276 if (ipv4_is_multicast(daddr)) { 2277 struct in_device *in_dev = __in_dev_get_rcu(dev); 2278 int our = 0; 2279 int err = -EINVAL; 2280 2281 if (!in_dev) 2282 return err; 2283 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2284 ip_hdr(skb)->protocol); 2285 2286 /* check l3 master if no match yet */ 2287 if (!our && netif_is_l3_slave(dev)) { 2288 struct in_device *l3_in_dev; 2289 2290 l3_in_dev = __in_dev_get_rcu(skb->dev); 2291 if (l3_in_dev) 2292 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2293 ip_hdr(skb)->protocol); 2294 } 2295 2296 if (our 2297 #ifdef CONFIG_IP_MROUTE 2298 || 2299 (!ipv4_is_local_multicast(daddr) && 2300 IN_DEV_MFORWARD(in_dev)) 2301 #endif 2302 ) { 2303 err = ip_route_input_mc(skb, daddr, saddr, 2304 tos, dev, our); 2305 } 2306 return err; 2307 } 2308 2309 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2310 } 2311 2312 /* called with rcu_read_lock() */ 2313 static struct rtable *__mkroute_output(const struct fib_result *res, 2314 const struct flowi4 *fl4, int orig_oif, 2315 struct net_device *dev_out, 2316 unsigned int flags) 2317 { 2318 struct fib_info *fi = res->fi; 2319 struct fib_nh_exception *fnhe; 2320 struct in_device *in_dev; 2321 u16 type = res->type; 2322 struct rtable *rth; 2323 bool do_cache; 2324 2325 in_dev = __in_dev_get_rcu(dev_out); 2326 if (!in_dev) 2327 return ERR_PTR(-EINVAL); 2328 2329 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2330 if (ipv4_is_loopback(fl4->saddr) && 2331 !(dev_out->flags & IFF_LOOPBACK) && 2332 !netif_is_l3_master(dev_out)) 2333 return ERR_PTR(-EINVAL); 2334 2335 if (ipv4_is_lbcast(fl4->daddr)) 2336 type = RTN_BROADCAST; 2337 else if (ipv4_is_multicast(fl4->daddr)) 2338 type = RTN_MULTICAST; 2339 else if (ipv4_is_zeronet(fl4->daddr)) 2340 return ERR_PTR(-EINVAL); 2341 2342 if (dev_out->flags & IFF_LOOPBACK) 2343 flags |= RTCF_LOCAL; 2344 2345 do_cache = true; 2346 if (type == RTN_BROADCAST) { 2347 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2348 fi = NULL; 2349 } else if (type == RTN_MULTICAST) { 2350 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2351 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2352 fl4->flowi4_proto)) 2353 flags &= ~RTCF_LOCAL; 2354 else 2355 do_cache = false; 2356 /* If multicast route do not exist use 2357 * default one, but do not gateway in this case. 2358 * Yes, it is hack. 2359 */ 2360 if (fi && res->prefixlen < 4) 2361 fi = NULL; 2362 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2363 (orig_oif != dev_out->ifindex)) { 2364 /* For local routes that require a particular output interface 2365 * we do not want to cache the result. Caching the result 2366 * causes incorrect behaviour when there are multiple source 2367 * addresses on the interface, the end result being that if the 2368 * intended recipient is waiting on that interface for the 2369 * packet he won't receive it because it will be delivered on 2370 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2371 * be set to the loopback interface as well. 2372 */ 2373 do_cache = false; 2374 } 2375 2376 fnhe = NULL; 2377 do_cache &= fi != NULL; 2378 if (fi) { 2379 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2380 struct rtable __rcu **prth; 2381 2382 fnhe = find_exception(nhc, fl4->daddr); 2383 if (!do_cache) 2384 goto add; 2385 if (fnhe) { 2386 prth = &fnhe->fnhe_rth_output; 2387 } else { 2388 if (unlikely(fl4->flowi4_flags & 2389 FLOWI_FLAG_KNOWN_NH && 2390 !(nhc->nhc_gw_family && 2391 nhc->nhc_scope == RT_SCOPE_LINK))) { 2392 do_cache = false; 2393 goto add; 2394 } 2395 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2396 } 2397 rth = rcu_dereference(*prth); 2398 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2399 return rth; 2400 } 2401 2402 add: 2403 rth = rt_dst_alloc(dev_out, flags, type, 2404 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2405 IN_DEV_CONF_GET(in_dev, NOXFRM), 2406 do_cache); 2407 if (!rth) 2408 return ERR_PTR(-ENOBUFS); 2409 2410 rth->rt_iif = orig_oif; 2411 2412 RT_CACHE_STAT_INC(out_slow_tot); 2413 2414 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2415 if (flags & RTCF_LOCAL && 2416 !(dev_out->flags & IFF_LOOPBACK)) { 2417 rth->dst.output = ip_mc_output; 2418 RT_CACHE_STAT_INC(out_slow_mc); 2419 } 2420 #ifdef CONFIG_IP_MROUTE 2421 if (type == RTN_MULTICAST) { 2422 if (IN_DEV_MFORWARD(in_dev) && 2423 !ipv4_is_local_multicast(fl4->daddr)) { 2424 rth->dst.input = ip_mr_input; 2425 rth->dst.output = ip_mc_output; 2426 } 2427 } 2428 #endif 2429 } 2430 2431 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2432 lwtunnel_set_redirect(&rth->dst); 2433 2434 return rth; 2435 } 2436 2437 /* 2438 * Major route resolver routine. 2439 */ 2440 2441 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2442 const struct sk_buff *skb) 2443 { 2444 __u8 tos = RT_FL_TOS(fl4); 2445 struct fib_result res = { 2446 .type = RTN_UNSPEC, 2447 .fi = NULL, 2448 .table = NULL, 2449 .tclassid = 0, 2450 }; 2451 struct rtable *rth; 2452 2453 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2454 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2455 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2456 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2457 2458 rcu_read_lock(); 2459 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2460 rcu_read_unlock(); 2461 2462 return rth; 2463 } 2464 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2465 2466 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2467 struct fib_result *res, 2468 const struct sk_buff *skb) 2469 { 2470 struct net_device *dev_out = NULL; 2471 int orig_oif = fl4->flowi4_oif; 2472 unsigned int flags = 0; 2473 struct rtable *rth; 2474 int err = -ENETUNREACH; 2475 2476 if (fl4->saddr) { 2477 rth = ERR_PTR(-EINVAL); 2478 if (ipv4_is_multicast(fl4->saddr) || 2479 ipv4_is_lbcast(fl4->saddr) || 2480 ipv4_is_zeronet(fl4->saddr)) 2481 goto out; 2482 2483 /* I removed check for oif == dev_out->oif here. 2484 It was wrong for two reasons: 2485 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2486 is assigned to multiple interfaces. 2487 2. Moreover, we are allowed to send packets with saddr 2488 of another iface. --ANK 2489 */ 2490 2491 if (fl4->flowi4_oif == 0 && 2492 (ipv4_is_multicast(fl4->daddr) || 2493 ipv4_is_lbcast(fl4->daddr))) { 2494 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2495 dev_out = __ip_dev_find(net, fl4->saddr, false); 2496 if (!dev_out) 2497 goto out; 2498 2499 /* Special hack: user can direct multicasts 2500 and limited broadcast via necessary interface 2501 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2502 This hack is not just for fun, it allows 2503 vic,vat and friends to work. 2504 They bind socket to loopback, set ttl to zero 2505 and expect that it will work. 2506 From the viewpoint of routing cache they are broken, 2507 because we are not allowed to build multicast path 2508 with loopback source addr (look, routing cache 2509 cannot know, that ttl is zero, so that packet 2510 will not leave this host and route is valid). 2511 Luckily, this hack is good workaround. 2512 */ 2513 2514 fl4->flowi4_oif = dev_out->ifindex; 2515 goto make_route; 2516 } 2517 2518 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2519 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2520 if (!__ip_dev_find(net, fl4->saddr, false)) 2521 goto out; 2522 } 2523 } 2524 2525 2526 if (fl4->flowi4_oif) { 2527 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2528 rth = ERR_PTR(-ENODEV); 2529 if (!dev_out) 2530 goto out; 2531 2532 /* RACE: Check return value of inet_select_addr instead. */ 2533 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2534 rth = ERR_PTR(-ENETUNREACH); 2535 goto out; 2536 } 2537 if (ipv4_is_local_multicast(fl4->daddr) || 2538 ipv4_is_lbcast(fl4->daddr) || 2539 fl4->flowi4_proto == IPPROTO_IGMP) { 2540 if (!fl4->saddr) 2541 fl4->saddr = inet_select_addr(dev_out, 0, 2542 RT_SCOPE_LINK); 2543 goto make_route; 2544 } 2545 if (!fl4->saddr) { 2546 if (ipv4_is_multicast(fl4->daddr)) 2547 fl4->saddr = inet_select_addr(dev_out, 0, 2548 fl4->flowi4_scope); 2549 else if (!fl4->daddr) 2550 fl4->saddr = inet_select_addr(dev_out, 0, 2551 RT_SCOPE_HOST); 2552 } 2553 } 2554 2555 if (!fl4->daddr) { 2556 fl4->daddr = fl4->saddr; 2557 if (!fl4->daddr) 2558 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2559 dev_out = net->loopback_dev; 2560 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2561 res->type = RTN_LOCAL; 2562 flags |= RTCF_LOCAL; 2563 goto make_route; 2564 } 2565 2566 err = fib_lookup(net, fl4, res, 0); 2567 if (err) { 2568 res->fi = NULL; 2569 res->table = NULL; 2570 if (fl4->flowi4_oif && 2571 (ipv4_is_multicast(fl4->daddr) || 2572 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2573 /* Apparently, routing tables are wrong. Assume, 2574 that the destination is on link. 2575 2576 WHY? DW. 2577 Because we are allowed to send to iface 2578 even if it has NO routes and NO assigned 2579 addresses. When oif is specified, routing 2580 tables are looked up with only one purpose: 2581 to catch if destination is gatewayed, rather than 2582 direct. Moreover, if MSG_DONTROUTE is set, 2583 we send packet, ignoring both routing tables 2584 and ifaddr state. --ANK 2585 2586 2587 We could make it even if oif is unknown, 2588 likely IPv6, but we do not. 2589 */ 2590 2591 if (fl4->saddr == 0) 2592 fl4->saddr = inet_select_addr(dev_out, 0, 2593 RT_SCOPE_LINK); 2594 res->type = RTN_UNICAST; 2595 goto make_route; 2596 } 2597 rth = ERR_PTR(err); 2598 goto out; 2599 } 2600 2601 if (res->type == RTN_LOCAL) { 2602 if (!fl4->saddr) { 2603 if (res->fi->fib_prefsrc) 2604 fl4->saddr = res->fi->fib_prefsrc; 2605 else 2606 fl4->saddr = fl4->daddr; 2607 } 2608 2609 /* L3 master device is the loopback for that domain */ 2610 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2611 net->loopback_dev; 2612 2613 /* make sure orig_oif points to fib result device even 2614 * though packet rx/tx happens over loopback or l3mdev 2615 */ 2616 orig_oif = FIB_RES_OIF(*res); 2617 2618 fl4->flowi4_oif = dev_out->ifindex; 2619 flags |= RTCF_LOCAL; 2620 goto make_route; 2621 } 2622 2623 fib_select_path(net, res, fl4, skb); 2624 2625 dev_out = FIB_RES_DEV(*res); 2626 fl4->flowi4_oif = dev_out->ifindex; 2627 2628 2629 make_route: 2630 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2631 2632 out: 2633 return rth; 2634 } 2635 2636 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2637 { 2638 return NULL; 2639 } 2640 2641 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2642 { 2643 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2644 2645 return mtu ? : dst->dev->mtu; 2646 } 2647 2648 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2649 struct sk_buff *skb, u32 mtu) 2650 { 2651 } 2652 2653 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2654 struct sk_buff *skb) 2655 { 2656 } 2657 2658 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2659 unsigned long old) 2660 { 2661 return NULL; 2662 } 2663 2664 static struct dst_ops ipv4_dst_blackhole_ops = { 2665 .family = AF_INET, 2666 .check = ipv4_blackhole_dst_check, 2667 .mtu = ipv4_blackhole_mtu, 2668 .default_advmss = ipv4_default_advmss, 2669 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2670 .redirect = ipv4_rt_blackhole_redirect, 2671 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2672 .neigh_lookup = ipv4_neigh_lookup, 2673 }; 2674 2675 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2676 { 2677 struct rtable *ort = (struct rtable *) dst_orig; 2678 struct rtable *rt; 2679 2680 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2681 if (rt) { 2682 struct dst_entry *new = &rt->dst; 2683 2684 new->__use = 1; 2685 new->input = dst_discard; 2686 new->output = dst_discard_out; 2687 2688 new->dev = net->loopback_dev; 2689 if (new->dev) 2690 dev_hold(new->dev); 2691 2692 rt->rt_is_input = ort->rt_is_input; 2693 rt->rt_iif = ort->rt_iif; 2694 rt->rt_pmtu = ort->rt_pmtu; 2695 rt->rt_mtu_locked = ort->rt_mtu_locked; 2696 2697 rt->rt_genid = rt_genid_ipv4(net); 2698 rt->rt_flags = ort->rt_flags; 2699 rt->rt_type = ort->rt_type; 2700 rt->rt_uses_gateway = ort->rt_uses_gateway; 2701 rt->rt_gw_family = ort->rt_gw_family; 2702 if (rt->rt_gw_family == AF_INET) 2703 rt->rt_gw4 = ort->rt_gw4; 2704 else if (rt->rt_gw_family == AF_INET6) 2705 rt->rt_gw6 = ort->rt_gw6; 2706 2707 INIT_LIST_HEAD(&rt->rt_uncached); 2708 } 2709 2710 dst_release(dst_orig); 2711 2712 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2713 } 2714 2715 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2716 const struct sock *sk) 2717 { 2718 struct rtable *rt = __ip_route_output_key(net, flp4); 2719 2720 if (IS_ERR(rt)) 2721 return rt; 2722 2723 if (flp4->flowi4_proto) 2724 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2725 flowi4_to_flowi(flp4), 2726 sk, 0); 2727 2728 return rt; 2729 } 2730 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2731 2732 /* called with rcu_read_lock held */ 2733 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2734 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2735 struct sk_buff *skb, u32 portid, u32 seq, 2736 unsigned int flags) 2737 { 2738 struct rtmsg *r; 2739 struct nlmsghdr *nlh; 2740 unsigned long expires = 0; 2741 u32 error; 2742 u32 metrics[RTAX_MAX]; 2743 2744 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2745 if (!nlh) 2746 return -EMSGSIZE; 2747 2748 r = nlmsg_data(nlh); 2749 r->rtm_family = AF_INET; 2750 r->rtm_dst_len = 32; 2751 r->rtm_src_len = 0; 2752 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2753 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2754 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2755 goto nla_put_failure; 2756 r->rtm_type = rt->rt_type; 2757 r->rtm_scope = RT_SCOPE_UNIVERSE; 2758 r->rtm_protocol = RTPROT_UNSPEC; 2759 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2760 if (rt->rt_flags & RTCF_NOTIFY) 2761 r->rtm_flags |= RTM_F_NOTIFY; 2762 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2763 r->rtm_flags |= RTCF_DOREDIRECT; 2764 2765 if (nla_put_in_addr(skb, RTA_DST, dst)) 2766 goto nla_put_failure; 2767 if (src) { 2768 r->rtm_src_len = 32; 2769 if (nla_put_in_addr(skb, RTA_SRC, src)) 2770 goto nla_put_failure; 2771 } 2772 if (rt->dst.dev && 2773 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2774 goto nla_put_failure; 2775 #ifdef CONFIG_IP_ROUTE_CLASSID 2776 if (rt->dst.tclassid && 2777 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2778 goto nla_put_failure; 2779 #endif 2780 if (fl4 && !rt_is_input_route(rt) && 2781 fl4->saddr != src) { 2782 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2783 goto nla_put_failure; 2784 } 2785 if (rt->rt_uses_gateway) { 2786 if (rt->rt_gw_family == AF_INET && 2787 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2788 goto nla_put_failure; 2789 } else if (rt->rt_gw_family == AF_INET6) { 2790 int alen = sizeof(struct in6_addr); 2791 struct nlattr *nla; 2792 struct rtvia *via; 2793 2794 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2795 if (!nla) 2796 goto nla_put_failure; 2797 2798 via = nla_data(nla); 2799 via->rtvia_family = AF_INET6; 2800 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2801 } 2802 } 2803 2804 expires = rt->dst.expires; 2805 if (expires) { 2806 unsigned long now = jiffies; 2807 2808 if (time_before(now, expires)) 2809 expires -= now; 2810 else 2811 expires = 0; 2812 } 2813 2814 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2815 if (rt->rt_pmtu && expires) 2816 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2817 if (rt->rt_mtu_locked && expires) 2818 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2819 if (rtnetlink_put_metrics(skb, metrics) < 0) 2820 goto nla_put_failure; 2821 2822 if (fl4) { 2823 if (fl4->flowi4_mark && 2824 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2825 goto nla_put_failure; 2826 2827 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2828 nla_put_u32(skb, RTA_UID, 2829 from_kuid_munged(current_user_ns(), 2830 fl4->flowi4_uid))) 2831 goto nla_put_failure; 2832 2833 if (rt_is_input_route(rt)) { 2834 #ifdef CONFIG_IP_MROUTE 2835 if (ipv4_is_multicast(dst) && 2836 !ipv4_is_local_multicast(dst) && 2837 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2838 int err = ipmr_get_route(net, skb, 2839 fl4->saddr, fl4->daddr, 2840 r, portid); 2841 2842 if (err <= 0) { 2843 if (err == 0) 2844 return 0; 2845 goto nla_put_failure; 2846 } 2847 } else 2848 #endif 2849 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2850 goto nla_put_failure; 2851 } 2852 } 2853 2854 error = rt->dst.error; 2855 2856 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2857 goto nla_put_failure; 2858 2859 nlmsg_end(skb, nlh); 2860 return 0; 2861 2862 nla_put_failure: 2863 nlmsg_cancel(skb, nlh); 2864 return -EMSGSIZE; 2865 } 2866 2867 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2868 struct netlink_callback *cb, u32 table_id, 2869 struct fnhe_hash_bucket *bucket, int genid, 2870 int *fa_index, int fa_start, unsigned int flags) 2871 { 2872 int i; 2873 2874 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2875 struct fib_nh_exception *fnhe; 2876 2877 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2878 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2879 struct rtable *rt; 2880 int err; 2881 2882 if (*fa_index < fa_start) 2883 goto next; 2884 2885 if (fnhe->fnhe_genid != genid) 2886 goto next; 2887 2888 if (fnhe->fnhe_expires && 2889 time_after(jiffies, fnhe->fnhe_expires)) 2890 goto next; 2891 2892 rt = rcu_dereference(fnhe->fnhe_rth_input); 2893 if (!rt) 2894 rt = rcu_dereference(fnhe->fnhe_rth_output); 2895 if (!rt) 2896 goto next; 2897 2898 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2899 table_id, NULL, skb, 2900 NETLINK_CB(cb->skb).portid, 2901 cb->nlh->nlmsg_seq, flags); 2902 if (err) 2903 return err; 2904 next: 2905 (*fa_index)++; 2906 } 2907 } 2908 2909 return 0; 2910 } 2911 2912 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2913 u32 table_id, struct fib_info *fi, 2914 int *fa_index, int fa_start, unsigned int flags) 2915 { 2916 struct net *net = sock_net(cb->skb->sk); 2917 int nhsel, genid = fnhe_genid(net); 2918 2919 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2920 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2921 struct fnhe_hash_bucket *bucket; 2922 int err; 2923 2924 if (nhc->nhc_flags & RTNH_F_DEAD) 2925 continue; 2926 2927 rcu_read_lock(); 2928 bucket = rcu_dereference(nhc->nhc_exceptions); 2929 err = 0; 2930 if (bucket) 2931 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 2932 genid, fa_index, fa_start, 2933 flags); 2934 rcu_read_unlock(); 2935 if (err) 2936 return err; 2937 } 2938 2939 return 0; 2940 } 2941 2942 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 2943 u8 ip_proto, __be16 sport, 2944 __be16 dport) 2945 { 2946 struct sk_buff *skb; 2947 struct iphdr *iph; 2948 2949 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2950 if (!skb) 2951 return NULL; 2952 2953 /* Reserve room for dummy headers, this skb can pass 2954 * through good chunk of routing engine. 2955 */ 2956 skb_reset_mac_header(skb); 2957 skb_reset_network_header(skb); 2958 skb->protocol = htons(ETH_P_IP); 2959 iph = skb_put(skb, sizeof(struct iphdr)); 2960 iph->protocol = ip_proto; 2961 iph->saddr = src; 2962 iph->daddr = dst; 2963 iph->version = 0x4; 2964 iph->frag_off = 0; 2965 iph->ihl = 0x5; 2966 skb_set_transport_header(skb, skb->len); 2967 2968 switch (iph->protocol) { 2969 case IPPROTO_UDP: { 2970 struct udphdr *udph; 2971 2972 udph = skb_put_zero(skb, sizeof(struct udphdr)); 2973 udph->source = sport; 2974 udph->dest = dport; 2975 udph->len = sizeof(struct udphdr); 2976 udph->check = 0; 2977 break; 2978 } 2979 case IPPROTO_TCP: { 2980 struct tcphdr *tcph; 2981 2982 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 2983 tcph->source = sport; 2984 tcph->dest = dport; 2985 tcph->doff = sizeof(struct tcphdr) / 4; 2986 tcph->rst = 1; 2987 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 2988 src, dst, 0); 2989 break; 2990 } 2991 case IPPROTO_ICMP: { 2992 struct icmphdr *icmph; 2993 2994 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 2995 icmph->type = ICMP_ECHO; 2996 icmph->code = 0; 2997 } 2998 } 2999 3000 return skb; 3001 } 3002 3003 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3004 const struct nlmsghdr *nlh, 3005 struct nlattr **tb, 3006 struct netlink_ext_ack *extack) 3007 { 3008 struct rtmsg *rtm; 3009 int i, err; 3010 3011 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3012 NL_SET_ERR_MSG(extack, 3013 "ipv4: Invalid header for route get request"); 3014 return -EINVAL; 3015 } 3016 3017 if (!netlink_strict_get_check(skb)) 3018 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3019 rtm_ipv4_policy, extack); 3020 3021 rtm = nlmsg_data(nlh); 3022 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3023 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3024 rtm->rtm_table || rtm->rtm_protocol || 3025 rtm->rtm_scope || rtm->rtm_type) { 3026 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3027 return -EINVAL; 3028 } 3029 3030 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3031 RTM_F_LOOKUP_TABLE | 3032 RTM_F_FIB_MATCH)) { 3033 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3034 return -EINVAL; 3035 } 3036 3037 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3038 rtm_ipv4_policy, extack); 3039 if (err) 3040 return err; 3041 3042 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3043 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3044 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3045 return -EINVAL; 3046 } 3047 3048 for (i = 0; i <= RTA_MAX; i++) { 3049 if (!tb[i]) 3050 continue; 3051 3052 switch (i) { 3053 case RTA_IIF: 3054 case RTA_OIF: 3055 case RTA_SRC: 3056 case RTA_DST: 3057 case RTA_IP_PROTO: 3058 case RTA_SPORT: 3059 case RTA_DPORT: 3060 case RTA_MARK: 3061 case RTA_UID: 3062 break; 3063 default: 3064 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3065 return -EINVAL; 3066 } 3067 } 3068 3069 return 0; 3070 } 3071 3072 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3073 struct netlink_ext_ack *extack) 3074 { 3075 struct net *net = sock_net(in_skb->sk); 3076 struct nlattr *tb[RTA_MAX+1]; 3077 u32 table_id = RT_TABLE_MAIN; 3078 __be16 sport = 0, dport = 0; 3079 struct fib_result res = {}; 3080 u8 ip_proto = IPPROTO_UDP; 3081 struct rtable *rt = NULL; 3082 struct sk_buff *skb; 3083 struct rtmsg *rtm; 3084 struct flowi4 fl4 = {}; 3085 __be32 dst = 0; 3086 __be32 src = 0; 3087 kuid_t uid; 3088 u32 iif; 3089 int err; 3090 int mark; 3091 3092 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3093 if (err < 0) 3094 return err; 3095 3096 rtm = nlmsg_data(nlh); 3097 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3098 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3099 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3100 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3101 if (tb[RTA_UID]) 3102 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3103 else 3104 uid = (iif ? INVALID_UID : current_uid()); 3105 3106 if (tb[RTA_IP_PROTO]) { 3107 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3108 &ip_proto, AF_INET, extack); 3109 if (err) 3110 return err; 3111 } 3112 3113 if (tb[RTA_SPORT]) 3114 sport = nla_get_be16(tb[RTA_SPORT]); 3115 3116 if (tb[RTA_DPORT]) 3117 dport = nla_get_be16(tb[RTA_DPORT]); 3118 3119 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3120 if (!skb) 3121 return -ENOBUFS; 3122 3123 fl4.daddr = dst; 3124 fl4.saddr = src; 3125 fl4.flowi4_tos = rtm->rtm_tos; 3126 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3127 fl4.flowi4_mark = mark; 3128 fl4.flowi4_uid = uid; 3129 if (sport) 3130 fl4.fl4_sport = sport; 3131 if (dport) 3132 fl4.fl4_dport = dport; 3133 fl4.flowi4_proto = ip_proto; 3134 3135 rcu_read_lock(); 3136 3137 if (iif) { 3138 struct net_device *dev; 3139 3140 dev = dev_get_by_index_rcu(net, iif); 3141 if (!dev) { 3142 err = -ENODEV; 3143 goto errout_rcu; 3144 } 3145 3146 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3147 skb->dev = dev; 3148 skb->mark = mark; 3149 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 3150 dev, &res); 3151 3152 rt = skb_rtable(skb); 3153 if (err == 0 && rt->dst.error) 3154 err = -rt->dst.error; 3155 } else { 3156 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3157 skb->dev = net->loopback_dev; 3158 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3159 err = 0; 3160 if (IS_ERR(rt)) 3161 err = PTR_ERR(rt); 3162 else 3163 skb_dst_set(skb, &rt->dst); 3164 } 3165 3166 if (err) 3167 goto errout_rcu; 3168 3169 if (rtm->rtm_flags & RTM_F_NOTIFY) 3170 rt->rt_flags |= RTCF_NOTIFY; 3171 3172 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3173 table_id = res.table ? res.table->tb_id : 0; 3174 3175 /* reset skb for netlink reply msg */ 3176 skb_trim(skb, 0); 3177 skb_reset_network_header(skb); 3178 skb_reset_transport_header(skb); 3179 skb_reset_mac_header(skb); 3180 3181 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3182 if (!res.fi) { 3183 err = fib_props[res.type].error; 3184 if (!err) 3185 err = -EHOSTUNREACH; 3186 goto errout_rcu; 3187 } 3188 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3189 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 3190 rt->rt_type, res.prefix, res.prefixlen, 3191 fl4.flowi4_tos, res.fi, 0); 3192 } else { 3193 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3194 NETLINK_CB(in_skb).portid, 3195 nlh->nlmsg_seq, 0); 3196 } 3197 if (err < 0) 3198 goto errout_rcu; 3199 3200 rcu_read_unlock(); 3201 3202 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3203 3204 errout_free: 3205 return err; 3206 errout_rcu: 3207 rcu_read_unlock(); 3208 kfree_skb(skb); 3209 goto errout_free; 3210 } 3211 3212 void ip_rt_multicast_event(struct in_device *in_dev) 3213 { 3214 rt_cache_flush(dev_net(in_dev->dev)); 3215 } 3216 3217 #ifdef CONFIG_SYSCTL 3218 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3219 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3220 static int ip_rt_gc_elasticity __read_mostly = 8; 3221 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3222 3223 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3224 void __user *buffer, 3225 size_t *lenp, loff_t *ppos) 3226 { 3227 struct net *net = (struct net *)__ctl->extra1; 3228 3229 if (write) { 3230 rt_cache_flush(net); 3231 fnhe_genid_bump(net); 3232 return 0; 3233 } 3234 3235 return -EINVAL; 3236 } 3237 3238 static struct ctl_table ipv4_route_table[] = { 3239 { 3240 .procname = "gc_thresh", 3241 .data = &ipv4_dst_ops.gc_thresh, 3242 .maxlen = sizeof(int), 3243 .mode = 0644, 3244 .proc_handler = proc_dointvec, 3245 }, 3246 { 3247 .procname = "max_size", 3248 .data = &ip_rt_max_size, 3249 .maxlen = sizeof(int), 3250 .mode = 0644, 3251 .proc_handler = proc_dointvec, 3252 }, 3253 { 3254 /* Deprecated. Use gc_min_interval_ms */ 3255 3256 .procname = "gc_min_interval", 3257 .data = &ip_rt_gc_min_interval, 3258 .maxlen = sizeof(int), 3259 .mode = 0644, 3260 .proc_handler = proc_dointvec_jiffies, 3261 }, 3262 { 3263 .procname = "gc_min_interval_ms", 3264 .data = &ip_rt_gc_min_interval, 3265 .maxlen = sizeof(int), 3266 .mode = 0644, 3267 .proc_handler = proc_dointvec_ms_jiffies, 3268 }, 3269 { 3270 .procname = "gc_timeout", 3271 .data = &ip_rt_gc_timeout, 3272 .maxlen = sizeof(int), 3273 .mode = 0644, 3274 .proc_handler = proc_dointvec_jiffies, 3275 }, 3276 { 3277 .procname = "gc_interval", 3278 .data = &ip_rt_gc_interval, 3279 .maxlen = sizeof(int), 3280 .mode = 0644, 3281 .proc_handler = proc_dointvec_jiffies, 3282 }, 3283 { 3284 .procname = "redirect_load", 3285 .data = &ip_rt_redirect_load, 3286 .maxlen = sizeof(int), 3287 .mode = 0644, 3288 .proc_handler = proc_dointvec, 3289 }, 3290 { 3291 .procname = "redirect_number", 3292 .data = &ip_rt_redirect_number, 3293 .maxlen = sizeof(int), 3294 .mode = 0644, 3295 .proc_handler = proc_dointvec, 3296 }, 3297 { 3298 .procname = "redirect_silence", 3299 .data = &ip_rt_redirect_silence, 3300 .maxlen = sizeof(int), 3301 .mode = 0644, 3302 .proc_handler = proc_dointvec, 3303 }, 3304 { 3305 .procname = "error_cost", 3306 .data = &ip_rt_error_cost, 3307 .maxlen = sizeof(int), 3308 .mode = 0644, 3309 .proc_handler = proc_dointvec, 3310 }, 3311 { 3312 .procname = "error_burst", 3313 .data = &ip_rt_error_burst, 3314 .maxlen = sizeof(int), 3315 .mode = 0644, 3316 .proc_handler = proc_dointvec, 3317 }, 3318 { 3319 .procname = "gc_elasticity", 3320 .data = &ip_rt_gc_elasticity, 3321 .maxlen = sizeof(int), 3322 .mode = 0644, 3323 .proc_handler = proc_dointvec, 3324 }, 3325 { 3326 .procname = "mtu_expires", 3327 .data = &ip_rt_mtu_expires, 3328 .maxlen = sizeof(int), 3329 .mode = 0644, 3330 .proc_handler = proc_dointvec_jiffies, 3331 }, 3332 { 3333 .procname = "min_pmtu", 3334 .data = &ip_rt_min_pmtu, 3335 .maxlen = sizeof(int), 3336 .mode = 0644, 3337 .proc_handler = proc_dointvec_minmax, 3338 .extra1 = &ip_min_valid_pmtu, 3339 }, 3340 { 3341 .procname = "min_adv_mss", 3342 .data = &ip_rt_min_advmss, 3343 .maxlen = sizeof(int), 3344 .mode = 0644, 3345 .proc_handler = proc_dointvec, 3346 }, 3347 { } 3348 }; 3349 3350 static const char ipv4_route_flush_procname[] = "flush"; 3351 3352 static struct ctl_table ipv4_route_flush_table[] = { 3353 { 3354 .procname = ipv4_route_flush_procname, 3355 .maxlen = sizeof(int), 3356 .mode = 0200, 3357 .proc_handler = ipv4_sysctl_rtcache_flush, 3358 }, 3359 { }, 3360 }; 3361 3362 static __net_init int sysctl_route_net_init(struct net *net) 3363 { 3364 struct ctl_table *tbl; 3365 3366 tbl = ipv4_route_flush_table; 3367 if (!net_eq(net, &init_net)) { 3368 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3369 if (!tbl) 3370 goto err_dup; 3371 3372 /* Don't export non-whitelisted sysctls to unprivileged users */ 3373 if (net->user_ns != &init_user_ns) { 3374 if (tbl[0].procname != ipv4_route_flush_procname) 3375 tbl[0].procname = NULL; 3376 } 3377 } 3378 tbl[0].extra1 = net; 3379 3380 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3381 if (!net->ipv4.route_hdr) 3382 goto err_reg; 3383 return 0; 3384 3385 err_reg: 3386 if (tbl != ipv4_route_flush_table) 3387 kfree(tbl); 3388 err_dup: 3389 return -ENOMEM; 3390 } 3391 3392 static __net_exit void sysctl_route_net_exit(struct net *net) 3393 { 3394 struct ctl_table *tbl; 3395 3396 tbl = net->ipv4.route_hdr->ctl_table_arg; 3397 unregister_net_sysctl_table(net->ipv4.route_hdr); 3398 BUG_ON(tbl == ipv4_route_flush_table); 3399 kfree(tbl); 3400 } 3401 3402 static __net_initdata struct pernet_operations sysctl_route_ops = { 3403 .init = sysctl_route_net_init, 3404 .exit = sysctl_route_net_exit, 3405 }; 3406 #endif 3407 3408 static __net_init int rt_genid_init(struct net *net) 3409 { 3410 atomic_set(&net->ipv4.rt_genid, 0); 3411 atomic_set(&net->fnhe_genid, 0); 3412 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3413 return 0; 3414 } 3415 3416 static __net_initdata struct pernet_operations rt_genid_ops = { 3417 .init = rt_genid_init, 3418 }; 3419 3420 static int __net_init ipv4_inetpeer_init(struct net *net) 3421 { 3422 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3423 3424 if (!bp) 3425 return -ENOMEM; 3426 inet_peer_base_init(bp); 3427 net->ipv4.peers = bp; 3428 return 0; 3429 } 3430 3431 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3432 { 3433 struct inet_peer_base *bp = net->ipv4.peers; 3434 3435 net->ipv4.peers = NULL; 3436 inetpeer_invalidate_tree(bp); 3437 kfree(bp); 3438 } 3439 3440 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3441 .init = ipv4_inetpeer_init, 3442 .exit = ipv4_inetpeer_exit, 3443 }; 3444 3445 #ifdef CONFIG_IP_ROUTE_CLASSID 3446 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3447 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3448 3449 int __init ip_rt_init(void) 3450 { 3451 int cpu; 3452 3453 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents), 3454 GFP_KERNEL); 3455 if (!ip_idents) 3456 panic("IP: failed to allocate ip_idents\n"); 3457 3458 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3459 3460 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3461 if (!ip_tstamps) 3462 panic("IP: failed to allocate ip_tstamps\n"); 3463 3464 for_each_possible_cpu(cpu) { 3465 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3466 3467 INIT_LIST_HEAD(&ul->head); 3468 spin_lock_init(&ul->lock); 3469 } 3470 #ifdef CONFIG_IP_ROUTE_CLASSID 3471 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3472 if (!ip_rt_acct) 3473 panic("IP: failed to allocate ip_rt_acct\n"); 3474 #endif 3475 3476 ipv4_dst_ops.kmem_cachep = 3477 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3478 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3479 3480 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3481 3482 if (dst_entries_init(&ipv4_dst_ops) < 0) 3483 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3484 3485 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3486 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3487 3488 ipv4_dst_ops.gc_thresh = ~0; 3489 ip_rt_max_size = INT_MAX; 3490 3491 devinet_init(); 3492 ip_fib_init(); 3493 3494 if (ip_rt_proc_init()) 3495 pr_err("Unable to create route proc files\n"); 3496 #ifdef CONFIG_XFRM 3497 xfrm_init(); 3498 xfrm4_init(); 3499 #endif 3500 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3501 RTNL_FLAG_DOIT_UNLOCKED); 3502 3503 #ifdef CONFIG_SYSCTL 3504 register_pernet_subsys(&sysctl_route_ops); 3505 #endif 3506 register_pernet_subsys(&rt_genid_ops); 3507 register_pernet_subsys(&ipv4_inetpeer_ops); 3508 return 0; 3509 } 3510 3511 #ifdef CONFIG_SYSCTL 3512 /* 3513 * We really need to sanitize the damn ipv4 init order, then all 3514 * this nonsense will go away. 3515 */ 3516 void __init ip_static_sysctl_init(void) 3517 { 3518 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3519 } 3520 #endif 3521