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->n_redirects)))) { 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->n_redirects; 925 #ifdef CONFIG_IP_ROUTE_VERBOSE 926 if (log_martians && 927 peer->n_redirects == ip_rt_redirect_number) 928 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 929 &ip_hdr(skb)->saddr, inet_iif(skb), 930 &ip_hdr(skb)->daddr, &gw); 931 #endif 932 } 933 out_put_peer: 934 inet_putpeer(peer); 935 } 936 937 static int ip_error(struct sk_buff *skb) 938 { 939 struct rtable *rt = skb_rtable(skb); 940 struct net_device *dev = skb->dev; 941 struct in_device *in_dev; 942 struct inet_peer *peer; 943 unsigned long now; 944 struct net *net; 945 bool send; 946 int code; 947 948 if (netif_is_l3_master(skb->dev)) { 949 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 950 if (!dev) 951 goto out; 952 } 953 954 in_dev = __in_dev_get_rcu(dev); 955 956 /* IP on this device is disabled. */ 957 if (!in_dev) 958 goto out; 959 960 net = dev_net(rt->dst.dev); 961 if (!IN_DEV_FORWARD(in_dev)) { 962 switch (rt->dst.error) { 963 case EHOSTUNREACH: 964 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 965 break; 966 967 case ENETUNREACH: 968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 969 break; 970 } 971 goto out; 972 } 973 974 switch (rt->dst.error) { 975 case EINVAL: 976 default: 977 goto out; 978 case EHOSTUNREACH: 979 code = ICMP_HOST_UNREACH; 980 break; 981 case ENETUNREACH: 982 code = ICMP_NET_UNREACH; 983 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 984 break; 985 case EACCES: 986 code = ICMP_PKT_FILTERED; 987 break; 988 } 989 990 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 991 l3mdev_master_ifindex(skb->dev), 1); 992 993 send = true; 994 if (peer) { 995 now = jiffies; 996 peer->rate_tokens += now - peer->rate_last; 997 if (peer->rate_tokens > ip_rt_error_burst) 998 peer->rate_tokens = ip_rt_error_burst; 999 peer->rate_last = now; 1000 if (peer->rate_tokens >= ip_rt_error_cost) 1001 peer->rate_tokens -= ip_rt_error_cost; 1002 else 1003 send = false; 1004 inet_putpeer(peer); 1005 } 1006 if (send) 1007 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1008 1009 out: kfree_skb(skb); 1010 return 0; 1011 } 1012 1013 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1014 { 1015 struct dst_entry *dst = &rt->dst; 1016 u32 old_mtu = ipv4_mtu(dst); 1017 struct fib_result res; 1018 bool lock = false; 1019 1020 if (ip_mtu_locked(dst)) 1021 return; 1022 1023 if (old_mtu < mtu) 1024 return; 1025 1026 if (mtu < ip_rt_min_pmtu) { 1027 lock = true; 1028 mtu = min(old_mtu, ip_rt_min_pmtu); 1029 } 1030 1031 if (rt->rt_pmtu == mtu && !lock && 1032 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1033 return; 1034 1035 rcu_read_lock(); 1036 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1037 struct fib_nh_common *nhc = FIB_RES_NHC(res); 1038 1039 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1040 jiffies + ip_rt_mtu_expires); 1041 } 1042 rcu_read_unlock(); 1043 } 1044 1045 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1046 struct sk_buff *skb, u32 mtu) 1047 { 1048 struct rtable *rt = (struct rtable *) dst; 1049 struct flowi4 fl4; 1050 1051 ip_rt_build_flow_key(&fl4, sk, skb); 1052 __ip_rt_update_pmtu(rt, &fl4, mtu); 1053 } 1054 1055 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1056 int oif, u8 protocol) 1057 { 1058 const struct iphdr *iph = (const struct iphdr *) skb->data; 1059 struct flowi4 fl4; 1060 struct rtable *rt; 1061 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1062 1063 __build_flow_key(net, &fl4, NULL, iph, oif, 1064 RT_TOS(iph->tos), protocol, mark, 0); 1065 rt = __ip_route_output_key(net, &fl4); 1066 if (!IS_ERR(rt)) { 1067 __ip_rt_update_pmtu(rt, &fl4, mtu); 1068 ip_rt_put(rt); 1069 } 1070 } 1071 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1072 1073 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1074 { 1075 const struct iphdr *iph = (const struct iphdr *) skb->data; 1076 struct flowi4 fl4; 1077 struct rtable *rt; 1078 1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1080 1081 if (!fl4.flowi4_mark) 1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1083 1084 rt = __ip_route_output_key(sock_net(sk), &fl4); 1085 if (!IS_ERR(rt)) { 1086 __ip_rt_update_pmtu(rt, &fl4, mtu); 1087 ip_rt_put(rt); 1088 } 1089 } 1090 1091 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1092 { 1093 const struct iphdr *iph = (const struct iphdr *) skb->data; 1094 struct flowi4 fl4; 1095 struct rtable *rt; 1096 struct dst_entry *odst = NULL; 1097 bool new = false; 1098 struct net *net = sock_net(sk); 1099 1100 bh_lock_sock(sk); 1101 1102 if (!ip_sk_accept_pmtu(sk)) 1103 goto out; 1104 1105 odst = sk_dst_get(sk); 1106 1107 if (sock_owned_by_user(sk) || !odst) { 1108 __ipv4_sk_update_pmtu(skb, sk, mtu); 1109 goto out; 1110 } 1111 1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1113 1114 rt = (struct rtable *)odst; 1115 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1117 if (IS_ERR(rt)) 1118 goto out; 1119 1120 new = true; 1121 } 1122 1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1124 1125 if (!dst_check(&rt->dst, 0)) { 1126 if (new) 1127 dst_release(&rt->dst); 1128 1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1130 if (IS_ERR(rt)) 1131 goto out; 1132 1133 new = true; 1134 } 1135 1136 if (new) 1137 sk_dst_set(sk, &rt->dst); 1138 1139 out: 1140 bh_unlock_sock(sk); 1141 dst_release(odst); 1142 } 1143 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1144 1145 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1146 int oif, u8 protocol) 1147 { 1148 const struct iphdr *iph = (const struct iphdr *) skb->data; 1149 struct flowi4 fl4; 1150 struct rtable *rt; 1151 1152 __build_flow_key(net, &fl4, NULL, iph, oif, 1153 RT_TOS(iph->tos), protocol, 0, 0); 1154 rt = __ip_route_output_key(net, &fl4); 1155 if (!IS_ERR(rt)) { 1156 __ip_do_redirect(rt, skb, &fl4, false); 1157 ip_rt_put(rt); 1158 } 1159 } 1160 EXPORT_SYMBOL_GPL(ipv4_redirect); 1161 1162 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1163 { 1164 const struct iphdr *iph = (const struct iphdr *) skb->data; 1165 struct flowi4 fl4; 1166 struct rtable *rt; 1167 struct net *net = sock_net(sk); 1168 1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1170 rt = __ip_route_output_key(net, &fl4); 1171 if (!IS_ERR(rt)) { 1172 __ip_do_redirect(rt, skb, &fl4, false); 1173 ip_rt_put(rt); 1174 } 1175 } 1176 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1177 1178 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1179 { 1180 struct rtable *rt = (struct rtable *) dst; 1181 1182 /* All IPV4 dsts are created with ->obsolete set to the value 1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1184 * into this function always. 1185 * 1186 * When a PMTU/redirect information update invalidates a route, 1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1188 * DST_OBSOLETE_DEAD. 1189 */ 1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1191 return NULL; 1192 return dst; 1193 } 1194 1195 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1196 { 1197 struct ip_options opt; 1198 int res; 1199 1200 /* Recompile ip options since IPCB may not be valid anymore. 1201 * Also check we have a reasonable ipv4 header. 1202 */ 1203 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1204 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1205 return; 1206 1207 memset(&opt, 0, sizeof(opt)); 1208 if (ip_hdr(skb)->ihl > 5) { 1209 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1210 return; 1211 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1212 1213 rcu_read_lock(); 1214 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1215 rcu_read_unlock(); 1216 1217 if (res) 1218 return; 1219 } 1220 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1221 } 1222 1223 static void ipv4_link_failure(struct sk_buff *skb) 1224 { 1225 struct rtable *rt; 1226 1227 ipv4_send_dest_unreach(skb); 1228 1229 rt = skb_rtable(skb); 1230 if (rt) 1231 dst_set_expires(&rt->dst, 0); 1232 } 1233 1234 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1235 { 1236 pr_debug("%s: %pI4 -> %pI4, %s\n", 1237 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1238 skb->dev ? skb->dev->name : "?"); 1239 kfree_skb(skb); 1240 WARN_ON(1); 1241 return 0; 1242 } 1243 1244 /* 1245 We do not cache source address of outgoing interface, 1246 because it is used only by IP RR, TS and SRR options, 1247 so that it out of fast path. 1248 1249 BTW remember: "addr" is allowed to be not aligned 1250 in IP options! 1251 */ 1252 1253 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1254 { 1255 __be32 src; 1256 1257 if (rt_is_output_route(rt)) 1258 src = ip_hdr(skb)->saddr; 1259 else { 1260 struct fib_result res; 1261 struct iphdr *iph = ip_hdr(skb); 1262 struct flowi4 fl4 = { 1263 .daddr = iph->daddr, 1264 .saddr = iph->saddr, 1265 .flowi4_tos = RT_TOS(iph->tos), 1266 .flowi4_oif = rt->dst.dev->ifindex, 1267 .flowi4_iif = skb->dev->ifindex, 1268 .flowi4_mark = skb->mark, 1269 }; 1270 1271 rcu_read_lock(); 1272 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1273 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1274 else 1275 src = inet_select_addr(rt->dst.dev, 1276 rt_nexthop(rt, iph->daddr), 1277 RT_SCOPE_UNIVERSE); 1278 rcu_read_unlock(); 1279 } 1280 memcpy(addr, &src, 4); 1281 } 1282 1283 #ifdef CONFIG_IP_ROUTE_CLASSID 1284 static void set_class_tag(struct rtable *rt, u32 tag) 1285 { 1286 if (!(rt->dst.tclassid & 0xFFFF)) 1287 rt->dst.tclassid |= tag & 0xFFFF; 1288 if (!(rt->dst.tclassid & 0xFFFF0000)) 1289 rt->dst.tclassid |= tag & 0xFFFF0000; 1290 } 1291 #endif 1292 1293 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1294 { 1295 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1296 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1297 ip_rt_min_advmss); 1298 1299 return min(advmss, IPV4_MAX_PMTU - header_size); 1300 } 1301 1302 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1303 { 1304 const struct rtable *rt = (const struct rtable *) dst; 1305 unsigned int mtu = rt->rt_pmtu; 1306 1307 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1308 mtu = dst_metric_raw(dst, RTAX_MTU); 1309 1310 if (mtu) 1311 return mtu; 1312 1313 mtu = READ_ONCE(dst->dev->mtu); 1314 1315 if (unlikely(ip_mtu_locked(dst))) { 1316 if (rt->rt_uses_gateway && mtu > 576) 1317 mtu = 576; 1318 } 1319 1320 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1321 1322 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1323 } 1324 1325 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1326 { 1327 struct fnhe_hash_bucket *hash; 1328 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1329 u32 hval = fnhe_hashfun(daddr); 1330 1331 spin_lock_bh(&fnhe_lock); 1332 1333 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1334 lockdep_is_held(&fnhe_lock)); 1335 hash += hval; 1336 1337 fnhe_p = &hash->chain; 1338 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1339 while (fnhe) { 1340 if (fnhe->fnhe_daddr == daddr) { 1341 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1342 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1343 /* set fnhe_daddr to 0 to ensure it won't bind with 1344 * new dsts in rt_bind_exception(). 1345 */ 1346 fnhe->fnhe_daddr = 0; 1347 fnhe_flush_routes(fnhe); 1348 kfree_rcu(fnhe, rcu); 1349 break; 1350 } 1351 fnhe_p = &fnhe->fnhe_next; 1352 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1353 lockdep_is_held(&fnhe_lock)); 1354 } 1355 1356 spin_unlock_bh(&fnhe_lock); 1357 } 1358 1359 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1360 __be32 daddr) 1361 { 1362 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1363 struct fib_nh_exception *fnhe; 1364 u32 hval; 1365 1366 if (!hash) 1367 return NULL; 1368 1369 hval = fnhe_hashfun(daddr); 1370 1371 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1372 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1373 if (fnhe->fnhe_daddr == daddr) { 1374 if (fnhe->fnhe_expires && 1375 time_after(jiffies, fnhe->fnhe_expires)) { 1376 ip_del_fnhe(nhc, daddr); 1377 break; 1378 } 1379 return fnhe; 1380 } 1381 } 1382 return NULL; 1383 } 1384 1385 /* MTU selection: 1386 * 1. mtu on route is locked - use it 1387 * 2. mtu from nexthop exception 1388 * 3. mtu from egress device 1389 */ 1390 1391 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1392 { 1393 struct fib_nh_common *nhc = res->nhc; 1394 struct net_device *dev = nhc->nhc_dev; 1395 struct fib_info *fi = res->fi; 1396 u32 mtu = 0; 1397 1398 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1399 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1400 mtu = fi->fib_mtu; 1401 1402 if (likely(!mtu)) { 1403 struct fib_nh_exception *fnhe; 1404 1405 fnhe = find_exception(nhc, daddr); 1406 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1407 mtu = fnhe->fnhe_pmtu; 1408 } 1409 1410 if (likely(!mtu)) 1411 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1412 1413 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1414 } 1415 1416 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1417 __be32 daddr, const bool do_cache) 1418 { 1419 bool ret = false; 1420 1421 spin_lock_bh(&fnhe_lock); 1422 1423 if (daddr == fnhe->fnhe_daddr) { 1424 struct rtable __rcu **porig; 1425 struct rtable *orig; 1426 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1427 1428 if (rt_is_input_route(rt)) 1429 porig = &fnhe->fnhe_rth_input; 1430 else 1431 porig = &fnhe->fnhe_rth_output; 1432 orig = rcu_dereference(*porig); 1433 1434 if (fnhe->fnhe_genid != genid) { 1435 fnhe->fnhe_genid = genid; 1436 fnhe->fnhe_gw = 0; 1437 fnhe->fnhe_pmtu = 0; 1438 fnhe->fnhe_expires = 0; 1439 fnhe->fnhe_mtu_locked = false; 1440 fnhe_flush_routes(fnhe); 1441 orig = NULL; 1442 } 1443 fill_route_from_fnhe(rt, fnhe); 1444 if (!rt->rt_gw4) { 1445 rt->rt_gw4 = daddr; 1446 rt->rt_gw_family = AF_INET; 1447 } 1448 1449 if (do_cache) { 1450 dst_hold(&rt->dst); 1451 rcu_assign_pointer(*porig, rt); 1452 if (orig) { 1453 dst_dev_put(&orig->dst); 1454 dst_release(&orig->dst); 1455 } 1456 ret = true; 1457 } 1458 1459 fnhe->fnhe_stamp = jiffies; 1460 } 1461 spin_unlock_bh(&fnhe_lock); 1462 1463 return ret; 1464 } 1465 1466 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1467 { 1468 struct rtable *orig, *prev, **p; 1469 bool ret = true; 1470 1471 if (rt_is_input_route(rt)) { 1472 p = (struct rtable **)&nhc->nhc_rth_input; 1473 } else { 1474 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1475 } 1476 orig = *p; 1477 1478 /* hold dst before doing cmpxchg() to avoid race condition 1479 * on this dst 1480 */ 1481 dst_hold(&rt->dst); 1482 prev = cmpxchg(p, orig, rt); 1483 if (prev == orig) { 1484 if (orig) { 1485 dst_dev_put(&orig->dst); 1486 dst_release(&orig->dst); 1487 } 1488 } else { 1489 dst_release(&rt->dst); 1490 ret = false; 1491 } 1492 1493 return ret; 1494 } 1495 1496 struct uncached_list { 1497 spinlock_t lock; 1498 struct list_head head; 1499 }; 1500 1501 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1502 1503 void rt_add_uncached_list(struct rtable *rt) 1504 { 1505 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1506 1507 rt->rt_uncached_list = ul; 1508 1509 spin_lock_bh(&ul->lock); 1510 list_add_tail(&rt->rt_uncached, &ul->head); 1511 spin_unlock_bh(&ul->lock); 1512 } 1513 1514 void rt_del_uncached_list(struct rtable *rt) 1515 { 1516 if (!list_empty(&rt->rt_uncached)) { 1517 struct uncached_list *ul = rt->rt_uncached_list; 1518 1519 spin_lock_bh(&ul->lock); 1520 list_del(&rt->rt_uncached); 1521 spin_unlock_bh(&ul->lock); 1522 } 1523 } 1524 1525 static void ipv4_dst_destroy(struct dst_entry *dst) 1526 { 1527 struct rtable *rt = (struct rtable *)dst; 1528 1529 ip_dst_metrics_put(dst); 1530 rt_del_uncached_list(rt); 1531 } 1532 1533 void rt_flush_dev(struct net_device *dev) 1534 { 1535 struct rtable *rt; 1536 int cpu; 1537 1538 for_each_possible_cpu(cpu) { 1539 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1540 1541 spin_lock_bh(&ul->lock); 1542 list_for_each_entry(rt, &ul->head, rt_uncached) { 1543 if (rt->dst.dev != dev) 1544 continue; 1545 rt->dst.dev = blackhole_netdev; 1546 dev_hold(rt->dst.dev); 1547 dev_put(dev); 1548 } 1549 spin_unlock_bh(&ul->lock); 1550 } 1551 } 1552 1553 static bool rt_cache_valid(const struct rtable *rt) 1554 { 1555 return rt && 1556 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1557 !rt_is_expired(rt); 1558 } 1559 1560 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1561 const struct fib_result *res, 1562 struct fib_nh_exception *fnhe, 1563 struct fib_info *fi, u16 type, u32 itag, 1564 const bool do_cache) 1565 { 1566 bool cached = false; 1567 1568 if (fi) { 1569 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1570 1571 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1572 rt->rt_uses_gateway = 1; 1573 rt->rt_gw_family = nhc->nhc_gw_family; 1574 /* only INET and INET6 are supported */ 1575 if (likely(nhc->nhc_gw_family == AF_INET)) 1576 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1577 else 1578 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1579 } 1580 1581 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1582 1583 #ifdef CONFIG_IP_ROUTE_CLASSID 1584 if (nhc->nhc_family == AF_INET) { 1585 struct fib_nh *nh; 1586 1587 nh = container_of(nhc, struct fib_nh, nh_common); 1588 rt->dst.tclassid = nh->nh_tclassid; 1589 } 1590 #endif 1591 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1592 if (unlikely(fnhe)) 1593 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1594 else if (do_cache) 1595 cached = rt_cache_route(nhc, rt); 1596 if (unlikely(!cached)) { 1597 /* Routes we intend to cache in nexthop exception or 1598 * FIB nexthop have the DST_NOCACHE bit clear. 1599 * However, if we are unsuccessful at storing this 1600 * route into the cache we really need to set it. 1601 */ 1602 if (!rt->rt_gw4) { 1603 rt->rt_gw_family = AF_INET; 1604 rt->rt_gw4 = daddr; 1605 } 1606 rt_add_uncached_list(rt); 1607 } 1608 } else 1609 rt_add_uncached_list(rt); 1610 1611 #ifdef CONFIG_IP_ROUTE_CLASSID 1612 #ifdef CONFIG_IP_MULTIPLE_TABLES 1613 set_class_tag(rt, res->tclassid); 1614 #endif 1615 set_class_tag(rt, itag); 1616 #endif 1617 } 1618 1619 struct rtable *rt_dst_alloc(struct net_device *dev, 1620 unsigned int flags, u16 type, 1621 bool nopolicy, bool noxfrm, bool will_cache) 1622 { 1623 struct rtable *rt; 1624 1625 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1626 (will_cache ? 0 : DST_HOST) | 1627 (nopolicy ? DST_NOPOLICY : 0) | 1628 (noxfrm ? DST_NOXFRM : 0)); 1629 1630 if (rt) { 1631 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1632 rt->rt_flags = flags; 1633 rt->rt_type = type; 1634 rt->rt_is_input = 0; 1635 rt->rt_iif = 0; 1636 rt->rt_pmtu = 0; 1637 rt->rt_mtu_locked = 0; 1638 rt->rt_uses_gateway = 0; 1639 rt->rt_gw_family = 0; 1640 rt->rt_gw4 = 0; 1641 INIT_LIST_HEAD(&rt->rt_uncached); 1642 1643 rt->dst.output = ip_output; 1644 if (flags & RTCF_LOCAL) 1645 rt->dst.input = ip_local_deliver; 1646 } 1647 1648 return rt; 1649 } 1650 EXPORT_SYMBOL(rt_dst_alloc); 1651 1652 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1653 { 1654 struct rtable *new_rt; 1655 1656 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1657 rt->dst.flags); 1658 1659 if (new_rt) { 1660 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1661 new_rt->rt_flags = rt->rt_flags; 1662 new_rt->rt_type = rt->rt_type; 1663 new_rt->rt_is_input = rt->rt_is_input; 1664 new_rt->rt_iif = rt->rt_iif; 1665 new_rt->rt_pmtu = rt->rt_pmtu; 1666 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1667 new_rt->rt_gw_family = rt->rt_gw_family; 1668 if (rt->rt_gw_family == AF_INET) 1669 new_rt->rt_gw4 = rt->rt_gw4; 1670 else if (rt->rt_gw_family == AF_INET6) 1671 new_rt->rt_gw6 = rt->rt_gw6; 1672 INIT_LIST_HEAD(&new_rt->rt_uncached); 1673 1674 new_rt->dst.flags |= DST_HOST; 1675 new_rt->dst.input = rt->dst.input; 1676 new_rt->dst.output = rt->dst.output; 1677 new_rt->dst.error = rt->dst.error; 1678 new_rt->dst.lastuse = jiffies; 1679 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1680 } 1681 return new_rt; 1682 } 1683 EXPORT_SYMBOL(rt_dst_clone); 1684 1685 /* called in rcu_read_lock() section */ 1686 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1687 u8 tos, struct net_device *dev, 1688 struct in_device *in_dev, u32 *itag) 1689 { 1690 int err; 1691 1692 /* Primary sanity checks. */ 1693 if (!in_dev) 1694 return -EINVAL; 1695 1696 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1697 skb->protocol != htons(ETH_P_IP)) 1698 return -EINVAL; 1699 1700 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1701 return -EINVAL; 1702 1703 if (ipv4_is_zeronet(saddr)) { 1704 if (!ipv4_is_local_multicast(daddr) && 1705 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1706 return -EINVAL; 1707 } else { 1708 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1709 in_dev, itag); 1710 if (err < 0) 1711 return err; 1712 } 1713 return 0; 1714 } 1715 1716 /* called in rcu_read_lock() section */ 1717 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1718 u8 tos, struct net_device *dev, int our) 1719 { 1720 struct in_device *in_dev = __in_dev_get_rcu(dev); 1721 unsigned int flags = RTCF_MULTICAST; 1722 struct rtable *rth; 1723 u32 itag = 0; 1724 int err; 1725 1726 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1727 if (err) 1728 return err; 1729 1730 if (our) 1731 flags |= RTCF_LOCAL; 1732 1733 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1734 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1735 if (!rth) 1736 return -ENOBUFS; 1737 1738 #ifdef CONFIG_IP_ROUTE_CLASSID 1739 rth->dst.tclassid = itag; 1740 #endif 1741 rth->dst.output = ip_rt_bug; 1742 rth->rt_is_input= 1; 1743 1744 #ifdef CONFIG_IP_MROUTE 1745 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1746 rth->dst.input = ip_mr_input; 1747 #endif 1748 RT_CACHE_STAT_INC(in_slow_mc); 1749 1750 skb_dst_set(skb, &rth->dst); 1751 return 0; 1752 } 1753 1754 1755 static void ip_handle_martian_source(struct net_device *dev, 1756 struct in_device *in_dev, 1757 struct sk_buff *skb, 1758 __be32 daddr, 1759 __be32 saddr) 1760 { 1761 RT_CACHE_STAT_INC(in_martian_src); 1762 #ifdef CONFIG_IP_ROUTE_VERBOSE 1763 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1764 /* 1765 * RFC1812 recommendation, if source is martian, 1766 * the only hint is MAC header. 1767 */ 1768 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1769 &daddr, &saddr, dev->name); 1770 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1771 print_hex_dump(KERN_WARNING, "ll header: ", 1772 DUMP_PREFIX_OFFSET, 16, 1, 1773 skb_mac_header(skb), 1774 dev->hard_header_len, false); 1775 } 1776 } 1777 #endif 1778 } 1779 1780 /* called in rcu_read_lock() section */ 1781 static int __mkroute_input(struct sk_buff *skb, 1782 const struct fib_result *res, 1783 struct in_device *in_dev, 1784 __be32 daddr, __be32 saddr, u32 tos) 1785 { 1786 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1787 struct net_device *dev = nhc->nhc_dev; 1788 struct fib_nh_exception *fnhe; 1789 struct rtable *rth; 1790 int err; 1791 struct in_device *out_dev; 1792 bool do_cache; 1793 u32 itag = 0; 1794 1795 /* get a working reference to the output device */ 1796 out_dev = __in_dev_get_rcu(dev); 1797 if (!out_dev) { 1798 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1799 return -EINVAL; 1800 } 1801 1802 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1803 in_dev->dev, in_dev, &itag); 1804 if (err < 0) { 1805 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1806 saddr); 1807 1808 goto cleanup; 1809 } 1810 1811 do_cache = res->fi && !itag; 1812 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1813 skb->protocol == htons(ETH_P_IP)) { 1814 __be32 gw; 1815 1816 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1817 if (IN_DEV_SHARED_MEDIA(out_dev) || 1818 inet_addr_onlink(out_dev, saddr, gw)) 1819 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1820 } 1821 1822 if (skb->protocol != htons(ETH_P_IP)) { 1823 /* Not IP (i.e. ARP). Do not create route, if it is 1824 * invalid for proxy arp. DNAT routes are always valid. 1825 * 1826 * Proxy arp feature have been extended to allow, ARP 1827 * replies back to the same interface, to support 1828 * Private VLAN switch technologies. See arp.c. 1829 */ 1830 if (out_dev == in_dev && 1831 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1832 err = -EINVAL; 1833 goto cleanup; 1834 } 1835 } 1836 1837 fnhe = find_exception(nhc, daddr); 1838 if (do_cache) { 1839 if (fnhe) 1840 rth = rcu_dereference(fnhe->fnhe_rth_input); 1841 else 1842 rth = rcu_dereference(nhc->nhc_rth_input); 1843 if (rt_cache_valid(rth)) { 1844 skb_dst_set_noref(skb, &rth->dst); 1845 goto out; 1846 } 1847 } 1848 1849 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1850 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1851 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1852 if (!rth) { 1853 err = -ENOBUFS; 1854 goto cleanup; 1855 } 1856 1857 rth->rt_is_input = 1; 1858 RT_CACHE_STAT_INC(in_slow_tot); 1859 1860 rth->dst.input = ip_forward; 1861 1862 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1863 do_cache); 1864 lwtunnel_set_redirect(&rth->dst); 1865 skb_dst_set(skb, &rth->dst); 1866 out: 1867 err = 0; 1868 cleanup: 1869 return err; 1870 } 1871 1872 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1873 /* To make ICMP packets follow the right flow, the multipath hash is 1874 * calculated from the inner IP addresses. 1875 */ 1876 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1877 struct flow_keys *hash_keys) 1878 { 1879 const struct iphdr *outer_iph = ip_hdr(skb); 1880 const struct iphdr *key_iph = outer_iph; 1881 const struct iphdr *inner_iph; 1882 const struct icmphdr *icmph; 1883 struct iphdr _inner_iph; 1884 struct icmphdr _icmph; 1885 1886 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1887 goto out; 1888 1889 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1890 goto out; 1891 1892 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1893 &_icmph); 1894 if (!icmph) 1895 goto out; 1896 1897 if (icmph->type != ICMP_DEST_UNREACH && 1898 icmph->type != ICMP_REDIRECT && 1899 icmph->type != ICMP_TIME_EXCEEDED && 1900 icmph->type != ICMP_PARAMETERPROB) 1901 goto out; 1902 1903 inner_iph = skb_header_pointer(skb, 1904 outer_iph->ihl * 4 + sizeof(_icmph), 1905 sizeof(_inner_iph), &_inner_iph); 1906 if (!inner_iph) 1907 goto out; 1908 1909 key_iph = inner_iph; 1910 out: 1911 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1912 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1913 } 1914 1915 /* if skb is set it will be used and fl4 can be NULL */ 1916 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1917 const struct sk_buff *skb, struct flow_keys *flkeys) 1918 { 1919 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1920 struct flow_keys hash_keys; 1921 u32 mhash; 1922 1923 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1924 case 0: 1925 memset(&hash_keys, 0, sizeof(hash_keys)); 1926 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1927 if (skb) { 1928 ip_multipath_l3_keys(skb, &hash_keys); 1929 } else { 1930 hash_keys.addrs.v4addrs.src = fl4->saddr; 1931 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1932 } 1933 break; 1934 case 1: 1935 /* skb is currently provided only when forwarding */ 1936 if (skb) { 1937 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1938 struct flow_keys keys; 1939 1940 /* short-circuit if we already have L4 hash present */ 1941 if (skb->l4_hash) 1942 return skb_get_hash_raw(skb) >> 1; 1943 1944 memset(&hash_keys, 0, sizeof(hash_keys)); 1945 1946 if (!flkeys) { 1947 skb_flow_dissect_flow_keys(skb, &keys, flag); 1948 flkeys = &keys; 1949 } 1950 1951 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1952 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1953 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1954 hash_keys.ports.src = flkeys->ports.src; 1955 hash_keys.ports.dst = flkeys->ports.dst; 1956 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1957 } else { 1958 memset(&hash_keys, 0, sizeof(hash_keys)); 1959 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1960 hash_keys.addrs.v4addrs.src = fl4->saddr; 1961 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1962 hash_keys.ports.src = fl4->fl4_sport; 1963 hash_keys.ports.dst = fl4->fl4_dport; 1964 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1965 } 1966 break; 1967 case 2: 1968 memset(&hash_keys, 0, sizeof(hash_keys)); 1969 /* skb is currently provided only when forwarding */ 1970 if (skb) { 1971 struct flow_keys keys; 1972 1973 skb_flow_dissect_flow_keys(skb, &keys, 0); 1974 /* Inner can be v4 or v6 */ 1975 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1976 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1977 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1981 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1982 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1983 hash_keys.tags.flow_label = keys.tags.flow_label; 1984 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1985 } else { 1986 /* Same as case 0 */ 1987 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1988 ip_multipath_l3_keys(skb, &hash_keys); 1989 } 1990 } else { 1991 /* Same as case 0 */ 1992 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1993 hash_keys.addrs.v4addrs.src = fl4->saddr; 1994 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1995 } 1996 break; 1997 } 1998 mhash = flow_hash_from_keys(&hash_keys); 1999 2000 if (multipath_hash) 2001 mhash = jhash_2words(mhash, multipath_hash, 0); 2002 2003 return mhash >> 1; 2004 } 2005 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2006 2007 static int ip_mkroute_input(struct sk_buff *skb, 2008 struct fib_result *res, 2009 struct in_device *in_dev, 2010 __be32 daddr, __be32 saddr, u32 tos, 2011 struct flow_keys *hkeys) 2012 { 2013 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2014 if (res->fi && fib_info_num_path(res->fi) > 1) { 2015 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2016 2017 fib_select_multipath(res, h); 2018 } 2019 #endif 2020 2021 /* create a routing cache entry */ 2022 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2023 } 2024 2025 /* 2026 * NOTE. We drop all the packets that has local source 2027 * addresses, because every properly looped back packet 2028 * must have correct destination already attached by output routine. 2029 * 2030 * Such approach solves two big problems: 2031 * 1. Not simplex devices are handled properly. 2032 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2033 * called with rcu_read_lock() 2034 */ 2035 2036 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2037 u8 tos, struct net_device *dev, 2038 struct fib_result *res) 2039 { 2040 struct in_device *in_dev = __in_dev_get_rcu(dev); 2041 struct flow_keys *flkeys = NULL, _flkeys; 2042 struct net *net = dev_net(dev); 2043 struct ip_tunnel_info *tun_info; 2044 int err = -EINVAL; 2045 unsigned int flags = 0; 2046 u32 itag = 0; 2047 struct rtable *rth; 2048 struct flowi4 fl4; 2049 bool do_cache = true; 2050 2051 /* IP on this device is disabled. */ 2052 2053 if (!in_dev) 2054 goto out; 2055 2056 /* Check for the most weird martians, which can be not detected 2057 by fib_lookup. 2058 */ 2059 2060 tun_info = skb_tunnel_info(skb); 2061 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2062 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2063 else 2064 fl4.flowi4_tun_key.tun_id = 0; 2065 skb_dst_drop(skb); 2066 2067 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2068 goto martian_source; 2069 2070 res->fi = NULL; 2071 res->table = NULL; 2072 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2073 goto brd_input; 2074 2075 /* Accept zero addresses only to limited broadcast; 2076 * I even do not know to fix it or not. Waiting for complains :-) 2077 */ 2078 if (ipv4_is_zeronet(saddr)) 2079 goto martian_source; 2080 2081 if (ipv4_is_zeronet(daddr)) 2082 goto martian_destination; 2083 2084 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2085 * and call it once if daddr or/and saddr are loopback addresses 2086 */ 2087 if (ipv4_is_loopback(daddr)) { 2088 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2089 goto martian_destination; 2090 } else if (ipv4_is_loopback(saddr)) { 2091 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2092 goto martian_source; 2093 } 2094 2095 /* 2096 * Now we are ready to route packet. 2097 */ 2098 fl4.flowi4_oif = 0; 2099 fl4.flowi4_iif = dev->ifindex; 2100 fl4.flowi4_mark = skb->mark; 2101 fl4.flowi4_tos = tos; 2102 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2103 fl4.flowi4_flags = 0; 2104 fl4.daddr = daddr; 2105 fl4.saddr = saddr; 2106 fl4.flowi4_uid = sock_net_uid(net, NULL); 2107 2108 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2109 flkeys = &_flkeys; 2110 } else { 2111 fl4.flowi4_proto = 0; 2112 fl4.fl4_sport = 0; 2113 fl4.fl4_dport = 0; 2114 } 2115 2116 err = fib_lookup(net, &fl4, res, 0); 2117 if (err != 0) { 2118 if (!IN_DEV_FORWARD(in_dev)) 2119 err = -EHOSTUNREACH; 2120 goto no_route; 2121 } 2122 2123 if (res->type == RTN_BROADCAST) { 2124 if (IN_DEV_BFORWARD(in_dev)) 2125 goto make_route; 2126 /* not do cache if bc_forwarding is enabled */ 2127 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2128 do_cache = false; 2129 goto brd_input; 2130 } 2131 2132 if (res->type == RTN_LOCAL) { 2133 err = fib_validate_source(skb, saddr, daddr, tos, 2134 0, dev, in_dev, &itag); 2135 if (err < 0) 2136 goto martian_source; 2137 goto local_input; 2138 } 2139 2140 if (!IN_DEV_FORWARD(in_dev)) { 2141 err = -EHOSTUNREACH; 2142 goto no_route; 2143 } 2144 if (res->type != RTN_UNICAST) 2145 goto martian_destination; 2146 2147 make_route: 2148 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2149 out: return err; 2150 2151 brd_input: 2152 if (skb->protocol != htons(ETH_P_IP)) 2153 goto e_inval; 2154 2155 if (!ipv4_is_zeronet(saddr)) { 2156 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2157 in_dev, &itag); 2158 if (err < 0) 2159 goto martian_source; 2160 } 2161 flags |= RTCF_BROADCAST; 2162 res->type = RTN_BROADCAST; 2163 RT_CACHE_STAT_INC(in_brd); 2164 2165 local_input: 2166 do_cache &= res->fi && !itag; 2167 if (do_cache) { 2168 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2169 2170 rth = rcu_dereference(nhc->nhc_rth_input); 2171 if (rt_cache_valid(rth)) { 2172 skb_dst_set_noref(skb, &rth->dst); 2173 err = 0; 2174 goto out; 2175 } 2176 } 2177 2178 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2179 flags | RTCF_LOCAL, res->type, 2180 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2181 if (!rth) 2182 goto e_nobufs; 2183 2184 rth->dst.output= ip_rt_bug; 2185 #ifdef CONFIG_IP_ROUTE_CLASSID 2186 rth->dst.tclassid = itag; 2187 #endif 2188 rth->rt_is_input = 1; 2189 2190 RT_CACHE_STAT_INC(in_slow_tot); 2191 if (res->type == RTN_UNREACHABLE) { 2192 rth->dst.input= ip_error; 2193 rth->dst.error= -err; 2194 rth->rt_flags &= ~RTCF_LOCAL; 2195 } 2196 2197 if (do_cache) { 2198 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2199 2200 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2201 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2202 WARN_ON(rth->dst.input == lwtunnel_input); 2203 rth->dst.lwtstate->orig_input = rth->dst.input; 2204 rth->dst.input = lwtunnel_input; 2205 } 2206 2207 if (unlikely(!rt_cache_route(nhc, rth))) 2208 rt_add_uncached_list(rth); 2209 } 2210 skb_dst_set(skb, &rth->dst); 2211 err = 0; 2212 goto out; 2213 2214 no_route: 2215 RT_CACHE_STAT_INC(in_no_route); 2216 res->type = RTN_UNREACHABLE; 2217 res->fi = NULL; 2218 res->table = NULL; 2219 goto local_input; 2220 2221 /* 2222 * Do not cache martian addresses: they should be logged (RFC1812) 2223 */ 2224 martian_destination: 2225 RT_CACHE_STAT_INC(in_martian_dst); 2226 #ifdef CONFIG_IP_ROUTE_VERBOSE 2227 if (IN_DEV_LOG_MARTIANS(in_dev)) 2228 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2229 &daddr, &saddr, dev->name); 2230 #endif 2231 2232 e_inval: 2233 err = -EINVAL; 2234 goto out; 2235 2236 e_nobufs: 2237 err = -ENOBUFS; 2238 goto out; 2239 2240 martian_source: 2241 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2242 goto out; 2243 } 2244 2245 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2246 u8 tos, struct net_device *dev) 2247 { 2248 struct fib_result res; 2249 int err; 2250 2251 tos &= IPTOS_RT_MASK; 2252 rcu_read_lock(); 2253 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2254 rcu_read_unlock(); 2255 2256 return err; 2257 } 2258 EXPORT_SYMBOL(ip_route_input_noref); 2259 2260 /* called with rcu_read_lock held */ 2261 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2262 u8 tos, struct net_device *dev, struct fib_result *res) 2263 { 2264 /* Multicast recognition logic is moved from route cache to here. 2265 The problem was that too many Ethernet cards have broken/missing 2266 hardware multicast filters :-( As result the host on multicasting 2267 network acquires a lot of useless route cache entries, sort of 2268 SDR messages from all the world. Now we try to get rid of them. 2269 Really, provided software IP multicast filter is organized 2270 reasonably (at least, hashed), it does not result in a slowdown 2271 comparing with route cache reject entries. 2272 Note, that multicast routers are not affected, because 2273 route cache entry is created eventually. 2274 */ 2275 if (ipv4_is_multicast(daddr)) { 2276 struct in_device *in_dev = __in_dev_get_rcu(dev); 2277 int our = 0; 2278 int err = -EINVAL; 2279 2280 if (!in_dev) 2281 return err; 2282 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2283 ip_hdr(skb)->protocol); 2284 2285 /* check l3 master if no match yet */ 2286 if (!our && netif_is_l3_slave(dev)) { 2287 struct in_device *l3_in_dev; 2288 2289 l3_in_dev = __in_dev_get_rcu(skb->dev); 2290 if (l3_in_dev) 2291 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2292 ip_hdr(skb)->protocol); 2293 } 2294 2295 if (our 2296 #ifdef CONFIG_IP_MROUTE 2297 || 2298 (!ipv4_is_local_multicast(daddr) && 2299 IN_DEV_MFORWARD(in_dev)) 2300 #endif 2301 ) { 2302 err = ip_route_input_mc(skb, daddr, saddr, 2303 tos, dev, our); 2304 } 2305 return err; 2306 } 2307 2308 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2309 } 2310 2311 /* called with rcu_read_lock() */ 2312 static struct rtable *__mkroute_output(const struct fib_result *res, 2313 const struct flowi4 *fl4, int orig_oif, 2314 struct net_device *dev_out, 2315 unsigned int flags) 2316 { 2317 struct fib_info *fi = res->fi; 2318 struct fib_nh_exception *fnhe; 2319 struct in_device *in_dev; 2320 u16 type = res->type; 2321 struct rtable *rth; 2322 bool do_cache; 2323 2324 in_dev = __in_dev_get_rcu(dev_out); 2325 if (!in_dev) 2326 return ERR_PTR(-EINVAL); 2327 2328 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2329 if (ipv4_is_loopback(fl4->saddr) && 2330 !(dev_out->flags & IFF_LOOPBACK) && 2331 !netif_is_l3_master(dev_out)) 2332 return ERR_PTR(-EINVAL); 2333 2334 if (ipv4_is_lbcast(fl4->daddr)) 2335 type = RTN_BROADCAST; 2336 else if (ipv4_is_multicast(fl4->daddr)) 2337 type = RTN_MULTICAST; 2338 else if (ipv4_is_zeronet(fl4->daddr)) 2339 return ERR_PTR(-EINVAL); 2340 2341 if (dev_out->flags & IFF_LOOPBACK) 2342 flags |= RTCF_LOCAL; 2343 2344 do_cache = true; 2345 if (type == RTN_BROADCAST) { 2346 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2347 fi = NULL; 2348 } else if (type == RTN_MULTICAST) { 2349 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2350 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2351 fl4->flowi4_proto)) 2352 flags &= ~RTCF_LOCAL; 2353 else 2354 do_cache = false; 2355 /* If multicast route do not exist use 2356 * default one, but do not gateway in this case. 2357 * Yes, it is hack. 2358 */ 2359 if (fi && res->prefixlen < 4) 2360 fi = NULL; 2361 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2362 (orig_oif != dev_out->ifindex)) { 2363 /* For local routes that require a particular output interface 2364 * we do not want to cache the result. Caching the result 2365 * causes incorrect behaviour when there are multiple source 2366 * addresses on the interface, the end result being that if the 2367 * intended recipient is waiting on that interface for the 2368 * packet he won't receive it because it will be delivered on 2369 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2370 * be set to the loopback interface as well. 2371 */ 2372 do_cache = false; 2373 } 2374 2375 fnhe = NULL; 2376 do_cache &= fi != NULL; 2377 if (fi) { 2378 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2379 struct rtable __rcu **prth; 2380 2381 fnhe = find_exception(nhc, fl4->daddr); 2382 if (!do_cache) 2383 goto add; 2384 if (fnhe) { 2385 prth = &fnhe->fnhe_rth_output; 2386 } else { 2387 if (unlikely(fl4->flowi4_flags & 2388 FLOWI_FLAG_KNOWN_NH && 2389 !(nhc->nhc_gw_family && 2390 nhc->nhc_scope == RT_SCOPE_LINK))) { 2391 do_cache = false; 2392 goto add; 2393 } 2394 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2395 } 2396 rth = rcu_dereference(*prth); 2397 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2398 return rth; 2399 } 2400 2401 add: 2402 rth = rt_dst_alloc(dev_out, flags, type, 2403 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2404 IN_DEV_CONF_GET(in_dev, NOXFRM), 2405 do_cache); 2406 if (!rth) 2407 return ERR_PTR(-ENOBUFS); 2408 2409 rth->rt_iif = orig_oif; 2410 2411 RT_CACHE_STAT_INC(out_slow_tot); 2412 2413 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2414 if (flags & RTCF_LOCAL && 2415 !(dev_out->flags & IFF_LOOPBACK)) { 2416 rth->dst.output = ip_mc_output; 2417 RT_CACHE_STAT_INC(out_slow_mc); 2418 } 2419 #ifdef CONFIG_IP_MROUTE 2420 if (type == RTN_MULTICAST) { 2421 if (IN_DEV_MFORWARD(in_dev) && 2422 !ipv4_is_local_multicast(fl4->daddr)) { 2423 rth->dst.input = ip_mr_input; 2424 rth->dst.output = ip_mc_output; 2425 } 2426 } 2427 #endif 2428 } 2429 2430 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2431 lwtunnel_set_redirect(&rth->dst); 2432 2433 return rth; 2434 } 2435 2436 /* 2437 * Major route resolver routine. 2438 */ 2439 2440 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2441 const struct sk_buff *skb) 2442 { 2443 __u8 tos = RT_FL_TOS(fl4); 2444 struct fib_result res = { 2445 .type = RTN_UNSPEC, 2446 .fi = NULL, 2447 .table = NULL, 2448 .tclassid = 0, 2449 }; 2450 struct rtable *rth; 2451 2452 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2453 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2454 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2455 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2456 2457 rcu_read_lock(); 2458 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2459 rcu_read_unlock(); 2460 2461 return rth; 2462 } 2463 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2464 2465 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2466 struct fib_result *res, 2467 const struct sk_buff *skb) 2468 { 2469 struct net_device *dev_out = NULL; 2470 int orig_oif = fl4->flowi4_oif; 2471 unsigned int flags = 0; 2472 struct rtable *rth; 2473 int err = -ENETUNREACH; 2474 2475 if (fl4->saddr) { 2476 rth = ERR_PTR(-EINVAL); 2477 if (ipv4_is_multicast(fl4->saddr) || 2478 ipv4_is_lbcast(fl4->saddr) || 2479 ipv4_is_zeronet(fl4->saddr)) 2480 goto out; 2481 2482 /* I removed check for oif == dev_out->oif here. 2483 It was wrong for two reasons: 2484 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2485 is assigned to multiple interfaces. 2486 2. Moreover, we are allowed to send packets with saddr 2487 of another iface. --ANK 2488 */ 2489 2490 if (fl4->flowi4_oif == 0 && 2491 (ipv4_is_multicast(fl4->daddr) || 2492 ipv4_is_lbcast(fl4->daddr))) { 2493 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2494 dev_out = __ip_dev_find(net, fl4->saddr, false); 2495 if (!dev_out) 2496 goto out; 2497 2498 /* Special hack: user can direct multicasts 2499 and limited broadcast via necessary interface 2500 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2501 This hack is not just for fun, it allows 2502 vic,vat and friends to work. 2503 They bind socket to loopback, set ttl to zero 2504 and expect that it will work. 2505 From the viewpoint of routing cache they are broken, 2506 because we are not allowed to build multicast path 2507 with loopback source addr (look, routing cache 2508 cannot know, that ttl is zero, so that packet 2509 will not leave this host and route is valid). 2510 Luckily, this hack is good workaround. 2511 */ 2512 2513 fl4->flowi4_oif = dev_out->ifindex; 2514 goto make_route; 2515 } 2516 2517 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2518 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2519 if (!__ip_dev_find(net, fl4->saddr, false)) 2520 goto out; 2521 } 2522 } 2523 2524 2525 if (fl4->flowi4_oif) { 2526 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2527 rth = ERR_PTR(-ENODEV); 2528 if (!dev_out) 2529 goto out; 2530 2531 /* RACE: Check return value of inet_select_addr instead. */ 2532 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2533 rth = ERR_PTR(-ENETUNREACH); 2534 goto out; 2535 } 2536 if (ipv4_is_local_multicast(fl4->daddr) || 2537 ipv4_is_lbcast(fl4->daddr) || 2538 fl4->flowi4_proto == IPPROTO_IGMP) { 2539 if (!fl4->saddr) 2540 fl4->saddr = inet_select_addr(dev_out, 0, 2541 RT_SCOPE_LINK); 2542 goto make_route; 2543 } 2544 if (!fl4->saddr) { 2545 if (ipv4_is_multicast(fl4->daddr)) 2546 fl4->saddr = inet_select_addr(dev_out, 0, 2547 fl4->flowi4_scope); 2548 else if (!fl4->daddr) 2549 fl4->saddr = inet_select_addr(dev_out, 0, 2550 RT_SCOPE_HOST); 2551 } 2552 } 2553 2554 if (!fl4->daddr) { 2555 fl4->daddr = fl4->saddr; 2556 if (!fl4->daddr) 2557 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2558 dev_out = net->loopback_dev; 2559 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2560 res->type = RTN_LOCAL; 2561 flags |= RTCF_LOCAL; 2562 goto make_route; 2563 } 2564 2565 err = fib_lookup(net, fl4, res, 0); 2566 if (err) { 2567 res->fi = NULL; 2568 res->table = NULL; 2569 if (fl4->flowi4_oif && 2570 (ipv4_is_multicast(fl4->daddr) || 2571 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2572 /* Apparently, routing tables are wrong. Assume, 2573 that the destination is on link. 2574 2575 WHY? DW. 2576 Because we are allowed to send to iface 2577 even if it has NO routes and NO assigned 2578 addresses. When oif is specified, routing 2579 tables are looked up with only one purpose: 2580 to catch if destination is gatewayed, rather than 2581 direct. Moreover, if MSG_DONTROUTE is set, 2582 we send packet, ignoring both routing tables 2583 and ifaddr state. --ANK 2584 2585 2586 We could make it even if oif is unknown, 2587 likely IPv6, but we do not. 2588 */ 2589 2590 if (fl4->saddr == 0) 2591 fl4->saddr = inet_select_addr(dev_out, 0, 2592 RT_SCOPE_LINK); 2593 res->type = RTN_UNICAST; 2594 goto make_route; 2595 } 2596 rth = ERR_PTR(err); 2597 goto out; 2598 } 2599 2600 if (res->type == RTN_LOCAL) { 2601 if (!fl4->saddr) { 2602 if (res->fi->fib_prefsrc) 2603 fl4->saddr = res->fi->fib_prefsrc; 2604 else 2605 fl4->saddr = fl4->daddr; 2606 } 2607 2608 /* L3 master device is the loopback for that domain */ 2609 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2610 net->loopback_dev; 2611 2612 /* make sure orig_oif points to fib result device even 2613 * though packet rx/tx happens over loopback or l3mdev 2614 */ 2615 orig_oif = FIB_RES_OIF(*res); 2616 2617 fl4->flowi4_oif = dev_out->ifindex; 2618 flags |= RTCF_LOCAL; 2619 goto make_route; 2620 } 2621 2622 fib_select_path(net, res, fl4, skb); 2623 2624 dev_out = FIB_RES_DEV(*res); 2625 fl4->flowi4_oif = dev_out->ifindex; 2626 2627 2628 make_route: 2629 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2630 2631 out: 2632 return rth; 2633 } 2634 2635 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2636 { 2637 return NULL; 2638 } 2639 2640 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2641 { 2642 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2643 2644 return mtu ? : dst->dev->mtu; 2645 } 2646 2647 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2648 struct sk_buff *skb, u32 mtu) 2649 { 2650 } 2651 2652 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2653 struct sk_buff *skb) 2654 { 2655 } 2656 2657 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2658 unsigned long old) 2659 { 2660 return NULL; 2661 } 2662 2663 static struct dst_ops ipv4_dst_blackhole_ops = { 2664 .family = AF_INET, 2665 .check = ipv4_blackhole_dst_check, 2666 .mtu = ipv4_blackhole_mtu, 2667 .default_advmss = ipv4_default_advmss, 2668 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2669 .redirect = ipv4_rt_blackhole_redirect, 2670 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2671 .neigh_lookup = ipv4_neigh_lookup, 2672 }; 2673 2674 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2675 { 2676 struct rtable *ort = (struct rtable *) dst_orig; 2677 struct rtable *rt; 2678 2679 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2680 if (rt) { 2681 struct dst_entry *new = &rt->dst; 2682 2683 new->__use = 1; 2684 new->input = dst_discard; 2685 new->output = dst_discard_out; 2686 2687 new->dev = net->loopback_dev; 2688 if (new->dev) 2689 dev_hold(new->dev); 2690 2691 rt->rt_is_input = ort->rt_is_input; 2692 rt->rt_iif = ort->rt_iif; 2693 rt->rt_pmtu = ort->rt_pmtu; 2694 rt->rt_mtu_locked = ort->rt_mtu_locked; 2695 2696 rt->rt_genid = rt_genid_ipv4(net); 2697 rt->rt_flags = ort->rt_flags; 2698 rt->rt_type = ort->rt_type; 2699 rt->rt_uses_gateway = ort->rt_uses_gateway; 2700 rt->rt_gw_family = ort->rt_gw_family; 2701 if (rt->rt_gw_family == AF_INET) 2702 rt->rt_gw4 = ort->rt_gw4; 2703 else if (rt->rt_gw_family == AF_INET6) 2704 rt->rt_gw6 = ort->rt_gw6; 2705 2706 INIT_LIST_HEAD(&rt->rt_uncached); 2707 } 2708 2709 dst_release(dst_orig); 2710 2711 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2712 } 2713 2714 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2715 const struct sock *sk) 2716 { 2717 struct rtable *rt = __ip_route_output_key(net, flp4); 2718 2719 if (IS_ERR(rt)) 2720 return rt; 2721 2722 if (flp4->flowi4_proto) 2723 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2724 flowi4_to_flowi(flp4), 2725 sk, 0); 2726 2727 return rt; 2728 } 2729 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2730 2731 /* called with rcu_read_lock held */ 2732 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2733 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2734 struct sk_buff *skb, u32 portid, u32 seq, 2735 unsigned int flags) 2736 { 2737 struct rtmsg *r; 2738 struct nlmsghdr *nlh; 2739 unsigned long expires = 0; 2740 u32 error; 2741 u32 metrics[RTAX_MAX]; 2742 2743 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2744 if (!nlh) 2745 return -EMSGSIZE; 2746 2747 r = nlmsg_data(nlh); 2748 r->rtm_family = AF_INET; 2749 r->rtm_dst_len = 32; 2750 r->rtm_src_len = 0; 2751 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2752 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2753 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2754 goto nla_put_failure; 2755 r->rtm_type = rt->rt_type; 2756 r->rtm_scope = RT_SCOPE_UNIVERSE; 2757 r->rtm_protocol = RTPROT_UNSPEC; 2758 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2759 if (rt->rt_flags & RTCF_NOTIFY) 2760 r->rtm_flags |= RTM_F_NOTIFY; 2761 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2762 r->rtm_flags |= RTCF_DOREDIRECT; 2763 2764 if (nla_put_in_addr(skb, RTA_DST, dst)) 2765 goto nla_put_failure; 2766 if (src) { 2767 r->rtm_src_len = 32; 2768 if (nla_put_in_addr(skb, RTA_SRC, src)) 2769 goto nla_put_failure; 2770 } 2771 if (rt->dst.dev && 2772 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2773 goto nla_put_failure; 2774 #ifdef CONFIG_IP_ROUTE_CLASSID 2775 if (rt->dst.tclassid && 2776 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2777 goto nla_put_failure; 2778 #endif 2779 if (fl4 && !rt_is_input_route(rt) && 2780 fl4->saddr != src) { 2781 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2782 goto nla_put_failure; 2783 } 2784 if (rt->rt_uses_gateway) { 2785 if (rt->rt_gw_family == AF_INET && 2786 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2787 goto nla_put_failure; 2788 } else if (rt->rt_gw_family == AF_INET6) { 2789 int alen = sizeof(struct in6_addr); 2790 struct nlattr *nla; 2791 struct rtvia *via; 2792 2793 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2794 if (!nla) 2795 goto nla_put_failure; 2796 2797 via = nla_data(nla); 2798 via->rtvia_family = AF_INET6; 2799 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2800 } 2801 } 2802 2803 expires = rt->dst.expires; 2804 if (expires) { 2805 unsigned long now = jiffies; 2806 2807 if (time_before(now, expires)) 2808 expires -= now; 2809 else 2810 expires = 0; 2811 } 2812 2813 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2814 if (rt->rt_pmtu && expires) 2815 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2816 if (rt->rt_mtu_locked && expires) 2817 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2818 if (rtnetlink_put_metrics(skb, metrics) < 0) 2819 goto nla_put_failure; 2820 2821 if (fl4) { 2822 if (fl4->flowi4_mark && 2823 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2824 goto nla_put_failure; 2825 2826 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2827 nla_put_u32(skb, RTA_UID, 2828 from_kuid_munged(current_user_ns(), 2829 fl4->flowi4_uid))) 2830 goto nla_put_failure; 2831 2832 if (rt_is_input_route(rt)) { 2833 #ifdef CONFIG_IP_MROUTE 2834 if (ipv4_is_multicast(dst) && 2835 !ipv4_is_local_multicast(dst) && 2836 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2837 int err = ipmr_get_route(net, skb, 2838 fl4->saddr, fl4->daddr, 2839 r, portid); 2840 2841 if (err <= 0) { 2842 if (err == 0) 2843 return 0; 2844 goto nla_put_failure; 2845 } 2846 } else 2847 #endif 2848 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2849 goto nla_put_failure; 2850 } 2851 } 2852 2853 error = rt->dst.error; 2854 2855 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2856 goto nla_put_failure; 2857 2858 nlmsg_end(skb, nlh); 2859 return 0; 2860 2861 nla_put_failure: 2862 nlmsg_cancel(skb, nlh); 2863 return -EMSGSIZE; 2864 } 2865 2866 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2867 struct netlink_callback *cb, u32 table_id, 2868 struct fnhe_hash_bucket *bucket, int genid, 2869 int *fa_index, int fa_start, unsigned int flags) 2870 { 2871 int i; 2872 2873 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2874 struct fib_nh_exception *fnhe; 2875 2876 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2877 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2878 struct rtable *rt; 2879 int err; 2880 2881 if (*fa_index < fa_start) 2882 goto next; 2883 2884 if (fnhe->fnhe_genid != genid) 2885 goto next; 2886 2887 if (fnhe->fnhe_expires && 2888 time_after(jiffies, fnhe->fnhe_expires)) 2889 goto next; 2890 2891 rt = rcu_dereference(fnhe->fnhe_rth_input); 2892 if (!rt) 2893 rt = rcu_dereference(fnhe->fnhe_rth_output); 2894 if (!rt) 2895 goto next; 2896 2897 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2898 table_id, NULL, skb, 2899 NETLINK_CB(cb->skb).portid, 2900 cb->nlh->nlmsg_seq, flags); 2901 if (err) 2902 return err; 2903 next: 2904 (*fa_index)++; 2905 } 2906 } 2907 2908 return 0; 2909 } 2910 2911 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2912 u32 table_id, struct fib_info *fi, 2913 int *fa_index, int fa_start, unsigned int flags) 2914 { 2915 struct net *net = sock_net(cb->skb->sk); 2916 int nhsel, genid = fnhe_genid(net); 2917 2918 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2919 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2920 struct fnhe_hash_bucket *bucket; 2921 int err; 2922 2923 if (nhc->nhc_flags & RTNH_F_DEAD) 2924 continue; 2925 2926 rcu_read_lock(); 2927 bucket = rcu_dereference(nhc->nhc_exceptions); 2928 err = 0; 2929 if (bucket) 2930 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 2931 genid, fa_index, fa_start, 2932 flags); 2933 rcu_read_unlock(); 2934 if (err) 2935 return err; 2936 } 2937 2938 return 0; 2939 } 2940 2941 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 2942 u8 ip_proto, __be16 sport, 2943 __be16 dport) 2944 { 2945 struct sk_buff *skb; 2946 struct iphdr *iph; 2947 2948 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2949 if (!skb) 2950 return NULL; 2951 2952 /* Reserve room for dummy headers, this skb can pass 2953 * through good chunk of routing engine. 2954 */ 2955 skb_reset_mac_header(skb); 2956 skb_reset_network_header(skb); 2957 skb->protocol = htons(ETH_P_IP); 2958 iph = skb_put(skb, sizeof(struct iphdr)); 2959 iph->protocol = ip_proto; 2960 iph->saddr = src; 2961 iph->daddr = dst; 2962 iph->version = 0x4; 2963 iph->frag_off = 0; 2964 iph->ihl = 0x5; 2965 skb_set_transport_header(skb, skb->len); 2966 2967 switch (iph->protocol) { 2968 case IPPROTO_UDP: { 2969 struct udphdr *udph; 2970 2971 udph = skb_put_zero(skb, sizeof(struct udphdr)); 2972 udph->source = sport; 2973 udph->dest = dport; 2974 udph->len = sizeof(struct udphdr); 2975 udph->check = 0; 2976 break; 2977 } 2978 case IPPROTO_TCP: { 2979 struct tcphdr *tcph; 2980 2981 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 2982 tcph->source = sport; 2983 tcph->dest = dport; 2984 tcph->doff = sizeof(struct tcphdr) / 4; 2985 tcph->rst = 1; 2986 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 2987 src, dst, 0); 2988 break; 2989 } 2990 case IPPROTO_ICMP: { 2991 struct icmphdr *icmph; 2992 2993 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 2994 icmph->type = ICMP_ECHO; 2995 icmph->code = 0; 2996 } 2997 } 2998 2999 return skb; 3000 } 3001 3002 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3003 const struct nlmsghdr *nlh, 3004 struct nlattr **tb, 3005 struct netlink_ext_ack *extack) 3006 { 3007 struct rtmsg *rtm; 3008 int i, err; 3009 3010 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3011 NL_SET_ERR_MSG(extack, 3012 "ipv4: Invalid header for route get request"); 3013 return -EINVAL; 3014 } 3015 3016 if (!netlink_strict_get_check(skb)) 3017 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3018 rtm_ipv4_policy, extack); 3019 3020 rtm = nlmsg_data(nlh); 3021 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3022 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3023 rtm->rtm_table || rtm->rtm_protocol || 3024 rtm->rtm_scope || rtm->rtm_type) { 3025 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3026 return -EINVAL; 3027 } 3028 3029 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3030 RTM_F_LOOKUP_TABLE | 3031 RTM_F_FIB_MATCH)) { 3032 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3033 return -EINVAL; 3034 } 3035 3036 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3037 rtm_ipv4_policy, extack); 3038 if (err) 3039 return err; 3040 3041 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3042 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3043 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3044 return -EINVAL; 3045 } 3046 3047 for (i = 0; i <= RTA_MAX; i++) { 3048 if (!tb[i]) 3049 continue; 3050 3051 switch (i) { 3052 case RTA_IIF: 3053 case RTA_OIF: 3054 case RTA_SRC: 3055 case RTA_DST: 3056 case RTA_IP_PROTO: 3057 case RTA_SPORT: 3058 case RTA_DPORT: 3059 case RTA_MARK: 3060 case RTA_UID: 3061 break; 3062 default: 3063 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3064 return -EINVAL; 3065 } 3066 } 3067 3068 return 0; 3069 } 3070 3071 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3072 struct netlink_ext_ack *extack) 3073 { 3074 struct net *net = sock_net(in_skb->sk); 3075 struct nlattr *tb[RTA_MAX+1]; 3076 u32 table_id = RT_TABLE_MAIN; 3077 __be16 sport = 0, dport = 0; 3078 struct fib_result res = {}; 3079 u8 ip_proto = IPPROTO_UDP; 3080 struct rtable *rt = NULL; 3081 struct sk_buff *skb; 3082 struct rtmsg *rtm; 3083 struct flowi4 fl4 = {}; 3084 __be32 dst = 0; 3085 __be32 src = 0; 3086 kuid_t uid; 3087 u32 iif; 3088 int err; 3089 int mark; 3090 3091 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3092 if (err < 0) 3093 return err; 3094 3095 rtm = nlmsg_data(nlh); 3096 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3097 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3098 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3099 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3100 if (tb[RTA_UID]) 3101 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3102 else 3103 uid = (iif ? INVALID_UID : current_uid()); 3104 3105 if (tb[RTA_IP_PROTO]) { 3106 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3107 &ip_proto, AF_INET, extack); 3108 if (err) 3109 return err; 3110 } 3111 3112 if (tb[RTA_SPORT]) 3113 sport = nla_get_be16(tb[RTA_SPORT]); 3114 3115 if (tb[RTA_DPORT]) 3116 dport = nla_get_be16(tb[RTA_DPORT]); 3117 3118 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3119 if (!skb) 3120 return -ENOBUFS; 3121 3122 fl4.daddr = dst; 3123 fl4.saddr = src; 3124 fl4.flowi4_tos = rtm->rtm_tos; 3125 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3126 fl4.flowi4_mark = mark; 3127 fl4.flowi4_uid = uid; 3128 if (sport) 3129 fl4.fl4_sport = sport; 3130 if (dport) 3131 fl4.fl4_dport = dport; 3132 fl4.flowi4_proto = ip_proto; 3133 3134 rcu_read_lock(); 3135 3136 if (iif) { 3137 struct net_device *dev; 3138 3139 dev = dev_get_by_index_rcu(net, iif); 3140 if (!dev) { 3141 err = -ENODEV; 3142 goto errout_rcu; 3143 } 3144 3145 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3146 skb->dev = dev; 3147 skb->mark = mark; 3148 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 3149 dev, &res); 3150 3151 rt = skb_rtable(skb); 3152 if (err == 0 && rt->dst.error) 3153 err = -rt->dst.error; 3154 } else { 3155 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3156 skb->dev = net->loopback_dev; 3157 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3158 err = 0; 3159 if (IS_ERR(rt)) 3160 err = PTR_ERR(rt); 3161 else 3162 skb_dst_set(skb, &rt->dst); 3163 } 3164 3165 if (err) 3166 goto errout_rcu; 3167 3168 if (rtm->rtm_flags & RTM_F_NOTIFY) 3169 rt->rt_flags |= RTCF_NOTIFY; 3170 3171 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3172 table_id = res.table ? res.table->tb_id : 0; 3173 3174 /* reset skb for netlink reply msg */ 3175 skb_trim(skb, 0); 3176 skb_reset_network_header(skb); 3177 skb_reset_transport_header(skb); 3178 skb_reset_mac_header(skb); 3179 3180 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3181 if (!res.fi) { 3182 err = fib_props[res.type].error; 3183 if (!err) 3184 err = -EHOSTUNREACH; 3185 goto errout_rcu; 3186 } 3187 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3188 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 3189 rt->rt_type, res.prefix, res.prefixlen, 3190 fl4.flowi4_tos, res.fi, 0); 3191 } else { 3192 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3193 NETLINK_CB(in_skb).portid, 3194 nlh->nlmsg_seq, 0); 3195 } 3196 if (err < 0) 3197 goto errout_rcu; 3198 3199 rcu_read_unlock(); 3200 3201 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3202 3203 errout_free: 3204 return err; 3205 errout_rcu: 3206 rcu_read_unlock(); 3207 kfree_skb(skb); 3208 goto errout_free; 3209 } 3210 3211 void ip_rt_multicast_event(struct in_device *in_dev) 3212 { 3213 rt_cache_flush(dev_net(in_dev->dev)); 3214 } 3215 3216 #ifdef CONFIG_SYSCTL 3217 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3218 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3219 static int ip_rt_gc_elasticity __read_mostly = 8; 3220 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3221 3222 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3223 void __user *buffer, 3224 size_t *lenp, loff_t *ppos) 3225 { 3226 struct net *net = (struct net *)__ctl->extra1; 3227 3228 if (write) { 3229 rt_cache_flush(net); 3230 fnhe_genid_bump(net); 3231 return 0; 3232 } 3233 3234 return -EINVAL; 3235 } 3236 3237 static struct ctl_table ipv4_route_table[] = { 3238 { 3239 .procname = "gc_thresh", 3240 .data = &ipv4_dst_ops.gc_thresh, 3241 .maxlen = sizeof(int), 3242 .mode = 0644, 3243 .proc_handler = proc_dointvec, 3244 }, 3245 { 3246 .procname = "max_size", 3247 .data = &ip_rt_max_size, 3248 .maxlen = sizeof(int), 3249 .mode = 0644, 3250 .proc_handler = proc_dointvec, 3251 }, 3252 { 3253 /* Deprecated. Use gc_min_interval_ms */ 3254 3255 .procname = "gc_min_interval", 3256 .data = &ip_rt_gc_min_interval, 3257 .maxlen = sizeof(int), 3258 .mode = 0644, 3259 .proc_handler = proc_dointvec_jiffies, 3260 }, 3261 { 3262 .procname = "gc_min_interval_ms", 3263 .data = &ip_rt_gc_min_interval, 3264 .maxlen = sizeof(int), 3265 .mode = 0644, 3266 .proc_handler = proc_dointvec_ms_jiffies, 3267 }, 3268 { 3269 .procname = "gc_timeout", 3270 .data = &ip_rt_gc_timeout, 3271 .maxlen = sizeof(int), 3272 .mode = 0644, 3273 .proc_handler = proc_dointvec_jiffies, 3274 }, 3275 { 3276 .procname = "gc_interval", 3277 .data = &ip_rt_gc_interval, 3278 .maxlen = sizeof(int), 3279 .mode = 0644, 3280 .proc_handler = proc_dointvec_jiffies, 3281 }, 3282 { 3283 .procname = "redirect_load", 3284 .data = &ip_rt_redirect_load, 3285 .maxlen = sizeof(int), 3286 .mode = 0644, 3287 .proc_handler = proc_dointvec, 3288 }, 3289 { 3290 .procname = "redirect_number", 3291 .data = &ip_rt_redirect_number, 3292 .maxlen = sizeof(int), 3293 .mode = 0644, 3294 .proc_handler = proc_dointvec, 3295 }, 3296 { 3297 .procname = "redirect_silence", 3298 .data = &ip_rt_redirect_silence, 3299 .maxlen = sizeof(int), 3300 .mode = 0644, 3301 .proc_handler = proc_dointvec, 3302 }, 3303 { 3304 .procname = "error_cost", 3305 .data = &ip_rt_error_cost, 3306 .maxlen = sizeof(int), 3307 .mode = 0644, 3308 .proc_handler = proc_dointvec, 3309 }, 3310 { 3311 .procname = "error_burst", 3312 .data = &ip_rt_error_burst, 3313 .maxlen = sizeof(int), 3314 .mode = 0644, 3315 .proc_handler = proc_dointvec, 3316 }, 3317 { 3318 .procname = "gc_elasticity", 3319 .data = &ip_rt_gc_elasticity, 3320 .maxlen = sizeof(int), 3321 .mode = 0644, 3322 .proc_handler = proc_dointvec, 3323 }, 3324 { 3325 .procname = "mtu_expires", 3326 .data = &ip_rt_mtu_expires, 3327 .maxlen = sizeof(int), 3328 .mode = 0644, 3329 .proc_handler = proc_dointvec_jiffies, 3330 }, 3331 { 3332 .procname = "min_pmtu", 3333 .data = &ip_rt_min_pmtu, 3334 .maxlen = sizeof(int), 3335 .mode = 0644, 3336 .proc_handler = proc_dointvec_minmax, 3337 .extra1 = &ip_min_valid_pmtu, 3338 }, 3339 { 3340 .procname = "min_adv_mss", 3341 .data = &ip_rt_min_advmss, 3342 .maxlen = sizeof(int), 3343 .mode = 0644, 3344 .proc_handler = proc_dointvec, 3345 }, 3346 { } 3347 }; 3348 3349 static const char ipv4_route_flush_procname[] = "flush"; 3350 3351 static struct ctl_table ipv4_route_flush_table[] = { 3352 { 3353 .procname = ipv4_route_flush_procname, 3354 .maxlen = sizeof(int), 3355 .mode = 0200, 3356 .proc_handler = ipv4_sysctl_rtcache_flush, 3357 }, 3358 { }, 3359 }; 3360 3361 static __net_init int sysctl_route_net_init(struct net *net) 3362 { 3363 struct ctl_table *tbl; 3364 3365 tbl = ipv4_route_flush_table; 3366 if (!net_eq(net, &init_net)) { 3367 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3368 if (!tbl) 3369 goto err_dup; 3370 3371 /* Don't export non-whitelisted sysctls to unprivileged users */ 3372 if (net->user_ns != &init_user_ns) { 3373 if (tbl[0].procname != ipv4_route_flush_procname) 3374 tbl[0].procname = NULL; 3375 } 3376 } 3377 tbl[0].extra1 = net; 3378 3379 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3380 if (!net->ipv4.route_hdr) 3381 goto err_reg; 3382 return 0; 3383 3384 err_reg: 3385 if (tbl != ipv4_route_flush_table) 3386 kfree(tbl); 3387 err_dup: 3388 return -ENOMEM; 3389 } 3390 3391 static __net_exit void sysctl_route_net_exit(struct net *net) 3392 { 3393 struct ctl_table *tbl; 3394 3395 tbl = net->ipv4.route_hdr->ctl_table_arg; 3396 unregister_net_sysctl_table(net->ipv4.route_hdr); 3397 BUG_ON(tbl == ipv4_route_flush_table); 3398 kfree(tbl); 3399 } 3400 3401 static __net_initdata struct pernet_operations sysctl_route_ops = { 3402 .init = sysctl_route_net_init, 3403 .exit = sysctl_route_net_exit, 3404 }; 3405 #endif 3406 3407 static __net_init int rt_genid_init(struct net *net) 3408 { 3409 atomic_set(&net->ipv4.rt_genid, 0); 3410 atomic_set(&net->fnhe_genid, 0); 3411 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3412 return 0; 3413 } 3414 3415 static __net_initdata struct pernet_operations rt_genid_ops = { 3416 .init = rt_genid_init, 3417 }; 3418 3419 static int __net_init ipv4_inetpeer_init(struct net *net) 3420 { 3421 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3422 3423 if (!bp) 3424 return -ENOMEM; 3425 inet_peer_base_init(bp); 3426 net->ipv4.peers = bp; 3427 return 0; 3428 } 3429 3430 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3431 { 3432 struct inet_peer_base *bp = net->ipv4.peers; 3433 3434 net->ipv4.peers = NULL; 3435 inetpeer_invalidate_tree(bp); 3436 kfree(bp); 3437 } 3438 3439 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3440 .init = ipv4_inetpeer_init, 3441 .exit = ipv4_inetpeer_exit, 3442 }; 3443 3444 #ifdef CONFIG_IP_ROUTE_CLASSID 3445 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3446 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3447 3448 int __init ip_rt_init(void) 3449 { 3450 int cpu; 3451 3452 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents), 3453 GFP_KERNEL); 3454 if (!ip_idents) 3455 panic("IP: failed to allocate ip_idents\n"); 3456 3457 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3458 3459 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3460 if (!ip_tstamps) 3461 panic("IP: failed to allocate ip_tstamps\n"); 3462 3463 for_each_possible_cpu(cpu) { 3464 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3465 3466 INIT_LIST_HEAD(&ul->head); 3467 spin_lock_init(&ul->lock); 3468 } 3469 #ifdef CONFIG_IP_ROUTE_CLASSID 3470 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3471 if (!ip_rt_acct) 3472 panic("IP: failed to allocate ip_rt_acct\n"); 3473 #endif 3474 3475 ipv4_dst_ops.kmem_cachep = 3476 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3477 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3478 3479 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3480 3481 if (dst_entries_init(&ipv4_dst_ops) < 0) 3482 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3483 3484 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3485 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3486 3487 ipv4_dst_ops.gc_thresh = ~0; 3488 ip_rt_max_size = INT_MAX; 3489 3490 devinet_init(); 3491 ip_fib_init(); 3492 3493 if (ip_rt_proc_init()) 3494 pr_err("Unable to create route proc files\n"); 3495 #ifdef CONFIG_XFRM 3496 xfrm_init(); 3497 xfrm4_init(); 3498 #endif 3499 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3500 RTNL_FLAG_DOIT_UNLOCKED); 3501 3502 #ifdef CONFIG_SYSCTL 3503 register_pernet_subsys(&sysctl_route_ops); 3504 #endif 3505 register_pernet_subsys(&rt_genid_ops); 3506 register_pernet_subsys(&ipv4_inetpeer_ops); 3507 return 0; 3508 } 3509 3510 #ifdef CONFIG_SYSCTL 3511 /* 3512 * We really need to sanitize the damn ipv4 init order, then all 3513 * this nonsense will go away. 3514 */ 3515 void __init ip_static_sysctl_init(void) 3516 { 3517 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3518 } 3519 #endif 3520