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_gw_family = AF_INET; 639 rt->rt_gw4 = fnhe->fnhe_gw; 640 } 641 } 642 643 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 644 __be32 gw, u32 pmtu, bool lock, 645 unsigned long expires) 646 { 647 struct fnhe_hash_bucket *hash; 648 struct fib_nh_exception *fnhe; 649 struct rtable *rt; 650 u32 genid, hval; 651 unsigned int i; 652 int depth; 653 654 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 655 hval = fnhe_hashfun(daddr); 656 657 spin_lock_bh(&fnhe_lock); 658 659 hash = rcu_dereference(nhc->nhc_exceptions); 660 if (!hash) { 661 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 662 if (!hash) 663 goto out_unlock; 664 rcu_assign_pointer(nhc->nhc_exceptions, hash); 665 } 666 667 hash += hval; 668 669 depth = 0; 670 for (fnhe = rcu_dereference(hash->chain); fnhe; 671 fnhe = rcu_dereference(fnhe->fnhe_next)) { 672 if (fnhe->fnhe_daddr == daddr) 673 break; 674 depth++; 675 } 676 677 if (fnhe) { 678 if (fnhe->fnhe_genid != genid) 679 fnhe->fnhe_genid = genid; 680 if (gw) 681 fnhe->fnhe_gw = gw; 682 if (pmtu) { 683 fnhe->fnhe_pmtu = pmtu; 684 fnhe->fnhe_mtu_locked = lock; 685 } 686 fnhe->fnhe_expires = max(1UL, expires); 687 /* Update all cached dsts too */ 688 rt = rcu_dereference(fnhe->fnhe_rth_input); 689 if (rt) 690 fill_route_from_fnhe(rt, fnhe); 691 rt = rcu_dereference(fnhe->fnhe_rth_output); 692 if (rt) 693 fill_route_from_fnhe(rt, fnhe); 694 } else { 695 if (depth > FNHE_RECLAIM_DEPTH) 696 fnhe = fnhe_oldest(hash); 697 else { 698 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 699 if (!fnhe) 700 goto out_unlock; 701 702 fnhe->fnhe_next = hash->chain; 703 rcu_assign_pointer(hash->chain, fnhe); 704 } 705 fnhe->fnhe_genid = genid; 706 fnhe->fnhe_daddr = daddr; 707 fnhe->fnhe_gw = gw; 708 fnhe->fnhe_pmtu = pmtu; 709 fnhe->fnhe_mtu_locked = lock; 710 fnhe->fnhe_expires = max(1UL, expires); 711 712 /* Exception created; mark the cached routes for the nexthop 713 * stale, so anyone caching it rechecks if this exception 714 * applies to them. 715 */ 716 rt = rcu_dereference(nhc->nhc_rth_input); 717 if (rt) 718 rt->dst.obsolete = DST_OBSOLETE_KILL; 719 720 for_each_possible_cpu(i) { 721 struct rtable __rcu **prt; 722 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 723 rt = rcu_dereference(*prt); 724 if (rt) 725 rt->dst.obsolete = DST_OBSOLETE_KILL; 726 } 727 } 728 729 fnhe->fnhe_stamp = jiffies; 730 731 out_unlock: 732 spin_unlock_bh(&fnhe_lock); 733 } 734 735 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 736 bool kill_route) 737 { 738 __be32 new_gw = icmp_hdr(skb)->un.gateway; 739 __be32 old_gw = ip_hdr(skb)->saddr; 740 struct net_device *dev = skb->dev; 741 struct in_device *in_dev; 742 struct fib_result res; 743 struct neighbour *n; 744 struct net *net; 745 746 switch (icmp_hdr(skb)->code & 7) { 747 case ICMP_REDIR_NET: 748 case ICMP_REDIR_NETTOS: 749 case ICMP_REDIR_HOST: 750 case ICMP_REDIR_HOSTTOS: 751 break; 752 753 default: 754 return; 755 } 756 757 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 758 return; 759 760 in_dev = __in_dev_get_rcu(dev); 761 if (!in_dev) 762 return; 763 764 net = dev_net(dev); 765 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 766 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 767 ipv4_is_zeronet(new_gw)) 768 goto reject_redirect; 769 770 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 771 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 772 goto reject_redirect; 773 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 774 goto reject_redirect; 775 } else { 776 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 777 goto reject_redirect; 778 } 779 780 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 781 if (!n) 782 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 783 if (!IS_ERR(n)) { 784 if (!(n->nud_state & NUD_VALID)) { 785 neigh_event_send(n, NULL); 786 } else { 787 if (fib_lookup(net, fl4, &res, 0) == 0) { 788 struct fib_nh_common *nhc = FIB_RES_NHC(res); 789 790 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 791 0, false, 792 jiffies + ip_rt_gc_timeout); 793 } 794 if (kill_route) 795 rt->dst.obsolete = DST_OBSOLETE_KILL; 796 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 797 } 798 neigh_release(n); 799 } 800 return; 801 802 reject_redirect: 803 #ifdef CONFIG_IP_ROUTE_VERBOSE 804 if (IN_DEV_LOG_MARTIANS(in_dev)) { 805 const struct iphdr *iph = (const struct iphdr *) skb->data; 806 __be32 daddr = iph->daddr; 807 __be32 saddr = iph->saddr; 808 809 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 810 " Advised path = %pI4 -> %pI4\n", 811 &old_gw, dev->name, &new_gw, 812 &saddr, &daddr); 813 } 814 #endif 815 ; 816 } 817 818 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 819 { 820 struct rtable *rt; 821 struct flowi4 fl4; 822 const struct iphdr *iph = (const struct iphdr *) skb->data; 823 struct net *net = dev_net(skb->dev); 824 int oif = skb->dev->ifindex; 825 u8 tos = RT_TOS(iph->tos); 826 u8 prot = iph->protocol; 827 u32 mark = skb->mark; 828 829 rt = (struct rtable *) dst; 830 831 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 832 __ip_do_redirect(rt, skb, &fl4, true); 833 } 834 835 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 836 { 837 struct rtable *rt = (struct rtable *)dst; 838 struct dst_entry *ret = dst; 839 840 if (rt) { 841 if (dst->obsolete > 0) { 842 ip_rt_put(rt); 843 ret = NULL; 844 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 845 rt->dst.expires) { 846 ip_rt_put(rt); 847 ret = NULL; 848 } 849 } 850 return ret; 851 } 852 853 /* 854 * Algorithm: 855 * 1. The first ip_rt_redirect_number redirects are sent 856 * with exponential backoff, then we stop sending them at all, 857 * assuming that the host ignores our redirects. 858 * 2. If we did not see packets requiring redirects 859 * during ip_rt_redirect_silence, we assume that the host 860 * forgot redirected route and start to send redirects again. 861 * 862 * This algorithm is much cheaper and more intelligent than dumb load limiting 863 * in icmp.c. 864 * 865 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 866 * and "frag. need" (breaks PMTU discovery) in icmp.c. 867 */ 868 869 void ip_rt_send_redirect(struct sk_buff *skb) 870 { 871 struct rtable *rt = skb_rtable(skb); 872 struct in_device *in_dev; 873 struct inet_peer *peer; 874 struct net *net; 875 int log_martians; 876 int vif; 877 878 rcu_read_lock(); 879 in_dev = __in_dev_get_rcu(rt->dst.dev); 880 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 881 rcu_read_unlock(); 882 return; 883 } 884 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 885 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 886 rcu_read_unlock(); 887 888 net = dev_net(rt->dst.dev); 889 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 890 if (!peer) { 891 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 892 rt_nexthop(rt, ip_hdr(skb)->daddr)); 893 return; 894 } 895 896 /* No redirected packets during ip_rt_redirect_silence; 897 * reset the algorithm. 898 */ 899 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 900 peer->rate_tokens = 0; 901 peer->n_redirects = 0; 902 } 903 904 /* Too many ignored redirects; do not send anything 905 * set dst.rate_last to the last seen redirected packet. 906 */ 907 if (peer->n_redirects >= ip_rt_redirect_number) { 908 peer->rate_last = jiffies; 909 goto out_put_peer; 910 } 911 912 /* Check for load limit; set rate_last to the latest sent 913 * redirect. 914 */ 915 if (peer->rate_tokens == 0 || 916 time_after(jiffies, 917 (peer->rate_last + 918 (ip_rt_redirect_load << peer->rate_tokens)))) { 919 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 920 921 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 922 peer->rate_last = jiffies; 923 ++peer->rate_tokens; 924 ++peer->n_redirects; 925 #ifdef CONFIG_IP_ROUTE_VERBOSE 926 if (log_martians && 927 peer->rate_tokens == 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_gw_family && 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_gw_family = nhc->nhc_gw_family; 1573 /* only INET and INET6 are supported */ 1574 if (likely(nhc->nhc_gw_family == AF_INET)) 1575 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1576 else 1577 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1578 } 1579 1580 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1581 1582 #ifdef CONFIG_IP_ROUTE_CLASSID 1583 if (nhc->nhc_family == AF_INET) { 1584 struct fib_nh *nh; 1585 1586 nh = container_of(nhc, struct fib_nh, nh_common); 1587 rt->dst.tclassid = nh->nh_tclassid; 1588 } 1589 #endif 1590 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1591 if (unlikely(fnhe)) 1592 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1593 else if (do_cache) 1594 cached = rt_cache_route(nhc, rt); 1595 if (unlikely(!cached)) { 1596 /* Routes we intend to cache in nexthop exception or 1597 * FIB nexthop have the DST_NOCACHE bit clear. 1598 * However, if we are unsuccessful at storing this 1599 * route into the cache we really need to set it. 1600 */ 1601 if (!rt->rt_gw4) { 1602 rt->rt_gw_family = AF_INET; 1603 rt->rt_gw4 = daddr; 1604 } 1605 rt_add_uncached_list(rt); 1606 } 1607 } else 1608 rt_add_uncached_list(rt); 1609 1610 #ifdef CONFIG_IP_ROUTE_CLASSID 1611 #ifdef CONFIG_IP_MULTIPLE_TABLES 1612 set_class_tag(rt, res->tclassid); 1613 #endif 1614 set_class_tag(rt, itag); 1615 #endif 1616 } 1617 1618 struct rtable *rt_dst_alloc(struct net_device *dev, 1619 unsigned int flags, u16 type, 1620 bool nopolicy, bool noxfrm, bool will_cache) 1621 { 1622 struct rtable *rt; 1623 1624 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1625 (will_cache ? 0 : DST_HOST) | 1626 (nopolicy ? DST_NOPOLICY : 0) | 1627 (noxfrm ? DST_NOXFRM : 0)); 1628 1629 if (rt) { 1630 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1631 rt->rt_flags = flags; 1632 rt->rt_type = type; 1633 rt->rt_is_input = 0; 1634 rt->rt_iif = 0; 1635 rt->rt_pmtu = 0; 1636 rt->rt_mtu_locked = 0; 1637 rt->rt_gw_family = 0; 1638 rt->rt_gw4 = 0; 1639 INIT_LIST_HEAD(&rt->rt_uncached); 1640 1641 rt->dst.output = ip_output; 1642 if (flags & RTCF_LOCAL) 1643 rt->dst.input = ip_local_deliver; 1644 } 1645 1646 return rt; 1647 } 1648 EXPORT_SYMBOL(rt_dst_alloc); 1649 1650 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1651 { 1652 struct rtable *new_rt; 1653 1654 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1655 rt->dst.flags); 1656 1657 if (new_rt) { 1658 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1659 new_rt->rt_flags = rt->rt_flags; 1660 new_rt->rt_type = rt->rt_type; 1661 new_rt->rt_is_input = rt->rt_is_input; 1662 new_rt->rt_iif = rt->rt_iif; 1663 new_rt->rt_pmtu = rt->rt_pmtu; 1664 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1665 new_rt->rt_gw_family = rt->rt_gw_family; 1666 if (rt->rt_gw_family == AF_INET) 1667 new_rt->rt_gw4 = rt->rt_gw4; 1668 else if (rt->rt_gw_family == AF_INET6) 1669 new_rt->rt_gw6 = rt->rt_gw6; 1670 INIT_LIST_HEAD(&new_rt->rt_uncached); 1671 1672 new_rt->dst.flags |= DST_HOST; 1673 new_rt->dst.input = rt->dst.input; 1674 new_rt->dst.output = rt->dst.output; 1675 new_rt->dst.error = rt->dst.error; 1676 new_rt->dst.lastuse = jiffies; 1677 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1678 } 1679 return new_rt; 1680 } 1681 EXPORT_SYMBOL(rt_dst_clone); 1682 1683 /* called in rcu_read_lock() section */ 1684 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1685 u8 tos, struct net_device *dev, 1686 struct in_device *in_dev, u32 *itag) 1687 { 1688 int err; 1689 1690 /* Primary sanity checks. */ 1691 if (!in_dev) 1692 return -EINVAL; 1693 1694 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1695 skb->protocol != htons(ETH_P_IP)) 1696 return -EINVAL; 1697 1698 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1699 return -EINVAL; 1700 1701 if (ipv4_is_zeronet(saddr)) { 1702 if (!ipv4_is_local_multicast(daddr) && 1703 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1704 return -EINVAL; 1705 } else { 1706 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1707 in_dev, itag); 1708 if (err < 0) 1709 return err; 1710 } 1711 return 0; 1712 } 1713 1714 /* called in rcu_read_lock() section */ 1715 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1716 u8 tos, struct net_device *dev, int our) 1717 { 1718 struct in_device *in_dev = __in_dev_get_rcu(dev); 1719 unsigned int flags = RTCF_MULTICAST; 1720 struct rtable *rth; 1721 u32 itag = 0; 1722 int err; 1723 1724 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1725 if (err) 1726 return err; 1727 1728 if (our) 1729 flags |= RTCF_LOCAL; 1730 1731 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1732 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1733 if (!rth) 1734 return -ENOBUFS; 1735 1736 #ifdef CONFIG_IP_ROUTE_CLASSID 1737 rth->dst.tclassid = itag; 1738 #endif 1739 rth->dst.output = ip_rt_bug; 1740 rth->rt_is_input= 1; 1741 1742 #ifdef CONFIG_IP_MROUTE 1743 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1744 rth->dst.input = ip_mr_input; 1745 #endif 1746 RT_CACHE_STAT_INC(in_slow_mc); 1747 1748 skb_dst_set(skb, &rth->dst); 1749 return 0; 1750 } 1751 1752 1753 static void ip_handle_martian_source(struct net_device *dev, 1754 struct in_device *in_dev, 1755 struct sk_buff *skb, 1756 __be32 daddr, 1757 __be32 saddr) 1758 { 1759 RT_CACHE_STAT_INC(in_martian_src); 1760 #ifdef CONFIG_IP_ROUTE_VERBOSE 1761 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1762 /* 1763 * RFC1812 recommendation, if source is martian, 1764 * the only hint is MAC header. 1765 */ 1766 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1767 &daddr, &saddr, dev->name); 1768 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1769 print_hex_dump(KERN_WARNING, "ll header: ", 1770 DUMP_PREFIX_OFFSET, 16, 1, 1771 skb_mac_header(skb), 1772 dev->hard_header_len, false); 1773 } 1774 } 1775 #endif 1776 } 1777 1778 /* called in rcu_read_lock() section */ 1779 static int __mkroute_input(struct sk_buff *skb, 1780 const struct fib_result *res, 1781 struct in_device *in_dev, 1782 __be32 daddr, __be32 saddr, u32 tos) 1783 { 1784 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1785 struct net_device *dev = nhc->nhc_dev; 1786 struct fib_nh_exception *fnhe; 1787 struct rtable *rth; 1788 int err; 1789 struct in_device *out_dev; 1790 bool do_cache; 1791 u32 itag = 0; 1792 1793 /* get a working reference to the output device */ 1794 out_dev = __in_dev_get_rcu(dev); 1795 if (!out_dev) { 1796 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1797 return -EINVAL; 1798 } 1799 1800 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1801 in_dev->dev, in_dev, &itag); 1802 if (err < 0) { 1803 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1804 saddr); 1805 1806 goto cleanup; 1807 } 1808 1809 do_cache = res->fi && !itag; 1810 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1811 skb->protocol == htons(ETH_P_IP)) { 1812 __be32 gw; 1813 1814 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1815 if (IN_DEV_SHARED_MEDIA(out_dev) || 1816 inet_addr_onlink(out_dev, saddr, gw)) 1817 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1818 } 1819 1820 if (skb->protocol != htons(ETH_P_IP)) { 1821 /* Not IP (i.e. ARP). Do not create route, if it is 1822 * invalid for proxy arp. DNAT routes are always valid. 1823 * 1824 * Proxy arp feature have been extended to allow, ARP 1825 * replies back to the same interface, to support 1826 * Private VLAN switch technologies. See arp.c. 1827 */ 1828 if (out_dev == in_dev && 1829 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1830 err = -EINVAL; 1831 goto cleanup; 1832 } 1833 } 1834 1835 fnhe = find_exception(nhc, daddr); 1836 if (do_cache) { 1837 if (fnhe) 1838 rth = rcu_dereference(fnhe->fnhe_rth_input); 1839 else 1840 rth = rcu_dereference(nhc->nhc_rth_input); 1841 if (rt_cache_valid(rth)) { 1842 skb_dst_set_noref(skb, &rth->dst); 1843 goto out; 1844 } 1845 } 1846 1847 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1848 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1849 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1850 if (!rth) { 1851 err = -ENOBUFS; 1852 goto cleanup; 1853 } 1854 1855 rth->rt_is_input = 1; 1856 RT_CACHE_STAT_INC(in_slow_tot); 1857 1858 rth->dst.input = ip_forward; 1859 1860 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1861 do_cache); 1862 lwtunnel_set_redirect(&rth->dst); 1863 skb_dst_set(skb, &rth->dst); 1864 out: 1865 err = 0; 1866 cleanup: 1867 return err; 1868 } 1869 1870 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1871 /* To make ICMP packets follow the right flow, the multipath hash is 1872 * calculated from the inner IP addresses. 1873 */ 1874 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1875 struct flow_keys *hash_keys) 1876 { 1877 const struct iphdr *outer_iph = ip_hdr(skb); 1878 const struct iphdr *key_iph = outer_iph; 1879 const struct iphdr *inner_iph; 1880 const struct icmphdr *icmph; 1881 struct iphdr _inner_iph; 1882 struct icmphdr _icmph; 1883 1884 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1885 goto out; 1886 1887 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1888 goto out; 1889 1890 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1891 &_icmph); 1892 if (!icmph) 1893 goto out; 1894 1895 if (icmph->type != ICMP_DEST_UNREACH && 1896 icmph->type != ICMP_REDIRECT && 1897 icmph->type != ICMP_TIME_EXCEEDED && 1898 icmph->type != ICMP_PARAMETERPROB) 1899 goto out; 1900 1901 inner_iph = skb_header_pointer(skb, 1902 outer_iph->ihl * 4 + sizeof(_icmph), 1903 sizeof(_inner_iph), &_inner_iph); 1904 if (!inner_iph) 1905 goto out; 1906 1907 key_iph = inner_iph; 1908 out: 1909 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1910 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1911 } 1912 1913 /* if skb is set it will be used and fl4 can be NULL */ 1914 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1915 const struct sk_buff *skb, struct flow_keys *flkeys) 1916 { 1917 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1918 struct flow_keys hash_keys; 1919 u32 mhash; 1920 1921 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1922 case 0: 1923 memset(&hash_keys, 0, sizeof(hash_keys)); 1924 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1925 if (skb) { 1926 ip_multipath_l3_keys(skb, &hash_keys); 1927 } else { 1928 hash_keys.addrs.v4addrs.src = fl4->saddr; 1929 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1930 } 1931 break; 1932 case 1: 1933 /* skb is currently provided only when forwarding */ 1934 if (skb) { 1935 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1936 struct flow_keys keys; 1937 1938 /* short-circuit if we already have L4 hash present */ 1939 if (skb->l4_hash) 1940 return skb_get_hash_raw(skb) >> 1; 1941 1942 memset(&hash_keys, 0, sizeof(hash_keys)); 1943 1944 if (!flkeys) { 1945 skb_flow_dissect_flow_keys(skb, &keys, flag); 1946 flkeys = &keys; 1947 } 1948 1949 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1950 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1951 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1952 hash_keys.ports.src = flkeys->ports.src; 1953 hash_keys.ports.dst = flkeys->ports.dst; 1954 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1955 } else { 1956 memset(&hash_keys, 0, sizeof(hash_keys)); 1957 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1958 hash_keys.addrs.v4addrs.src = fl4->saddr; 1959 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1960 hash_keys.ports.src = fl4->fl4_sport; 1961 hash_keys.ports.dst = fl4->fl4_dport; 1962 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1963 } 1964 break; 1965 case 2: 1966 memset(&hash_keys, 0, sizeof(hash_keys)); 1967 /* skb is currently provided only when forwarding */ 1968 if (skb) { 1969 struct flow_keys keys; 1970 1971 skb_flow_dissect_flow_keys(skb, &keys, 0); 1972 /* Inner can be v4 or v6 */ 1973 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1974 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1975 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1976 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1977 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1978 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1979 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1980 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1981 hash_keys.tags.flow_label = keys.tags.flow_label; 1982 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1983 } else { 1984 /* Same as case 0 */ 1985 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1986 ip_multipath_l3_keys(skb, &hash_keys); 1987 } 1988 } else { 1989 /* Same as case 0 */ 1990 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1991 hash_keys.addrs.v4addrs.src = fl4->saddr; 1992 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1993 } 1994 break; 1995 } 1996 mhash = flow_hash_from_keys(&hash_keys); 1997 1998 if (multipath_hash) 1999 mhash = jhash_2words(mhash, multipath_hash, 0); 2000 2001 return mhash >> 1; 2002 } 2003 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2004 2005 static int ip_mkroute_input(struct sk_buff *skb, 2006 struct fib_result *res, 2007 struct in_device *in_dev, 2008 __be32 daddr, __be32 saddr, u32 tos, 2009 struct flow_keys *hkeys) 2010 { 2011 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2012 if (res->fi && fib_info_num_path(res->fi) > 1) { 2013 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2014 2015 fib_select_multipath(res, h); 2016 } 2017 #endif 2018 2019 /* create a routing cache entry */ 2020 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2021 } 2022 2023 /* 2024 * NOTE. We drop all the packets that has local source 2025 * addresses, because every properly looped back packet 2026 * must have correct destination already attached by output routine. 2027 * 2028 * Such approach solves two big problems: 2029 * 1. Not simplex devices are handled properly. 2030 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2031 * called with rcu_read_lock() 2032 */ 2033 2034 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2035 u8 tos, struct net_device *dev, 2036 struct fib_result *res) 2037 { 2038 struct in_device *in_dev = __in_dev_get_rcu(dev); 2039 struct flow_keys *flkeys = NULL, _flkeys; 2040 struct net *net = dev_net(dev); 2041 struct ip_tunnel_info *tun_info; 2042 int err = -EINVAL; 2043 unsigned int flags = 0; 2044 u32 itag = 0; 2045 struct rtable *rth; 2046 struct flowi4 fl4; 2047 bool do_cache = true; 2048 2049 /* IP on this device is disabled. */ 2050 2051 if (!in_dev) 2052 goto out; 2053 2054 /* Check for the most weird martians, which can be not detected 2055 by fib_lookup. 2056 */ 2057 2058 tun_info = skb_tunnel_info(skb); 2059 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2060 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2061 else 2062 fl4.flowi4_tun_key.tun_id = 0; 2063 skb_dst_drop(skb); 2064 2065 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2066 goto martian_source; 2067 2068 res->fi = NULL; 2069 res->table = NULL; 2070 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2071 goto brd_input; 2072 2073 /* Accept zero addresses only to limited broadcast; 2074 * I even do not know to fix it or not. Waiting for complains :-) 2075 */ 2076 if (ipv4_is_zeronet(saddr)) 2077 goto martian_source; 2078 2079 if (ipv4_is_zeronet(daddr)) 2080 goto martian_destination; 2081 2082 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2083 * and call it once if daddr or/and saddr are loopback addresses 2084 */ 2085 if (ipv4_is_loopback(daddr)) { 2086 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2087 goto martian_destination; 2088 } else if (ipv4_is_loopback(saddr)) { 2089 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2090 goto martian_source; 2091 } 2092 2093 /* 2094 * Now we are ready to route packet. 2095 */ 2096 fl4.flowi4_oif = 0; 2097 fl4.flowi4_iif = dev->ifindex; 2098 fl4.flowi4_mark = skb->mark; 2099 fl4.flowi4_tos = tos; 2100 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2101 fl4.flowi4_flags = 0; 2102 fl4.daddr = daddr; 2103 fl4.saddr = saddr; 2104 fl4.flowi4_uid = sock_net_uid(net, NULL); 2105 2106 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2107 flkeys = &_flkeys; 2108 } else { 2109 fl4.flowi4_proto = 0; 2110 fl4.fl4_sport = 0; 2111 fl4.fl4_dport = 0; 2112 } 2113 2114 err = fib_lookup(net, &fl4, res, 0); 2115 if (err != 0) { 2116 if (!IN_DEV_FORWARD(in_dev)) 2117 err = -EHOSTUNREACH; 2118 goto no_route; 2119 } 2120 2121 if (res->type == RTN_BROADCAST) { 2122 if (IN_DEV_BFORWARD(in_dev)) 2123 goto make_route; 2124 /* not do cache if bc_forwarding is enabled */ 2125 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2126 do_cache = false; 2127 goto brd_input; 2128 } 2129 2130 if (res->type == RTN_LOCAL) { 2131 err = fib_validate_source(skb, saddr, daddr, tos, 2132 0, dev, in_dev, &itag); 2133 if (err < 0) 2134 goto martian_source; 2135 goto local_input; 2136 } 2137 2138 if (!IN_DEV_FORWARD(in_dev)) { 2139 err = -EHOSTUNREACH; 2140 goto no_route; 2141 } 2142 if (res->type != RTN_UNICAST) 2143 goto martian_destination; 2144 2145 make_route: 2146 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2147 out: return err; 2148 2149 brd_input: 2150 if (skb->protocol != htons(ETH_P_IP)) 2151 goto e_inval; 2152 2153 if (!ipv4_is_zeronet(saddr)) { 2154 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2155 in_dev, &itag); 2156 if (err < 0) 2157 goto martian_source; 2158 } 2159 flags |= RTCF_BROADCAST; 2160 res->type = RTN_BROADCAST; 2161 RT_CACHE_STAT_INC(in_brd); 2162 2163 local_input: 2164 do_cache &= res->fi && !itag; 2165 if (do_cache) { 2166 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2167 2168 rth = rcu_dereference(nhc->nhc_rth_input); 2169 if (rt_cache_valid(rth)) { 2170 skb_dst_set_noref(skb, &rth->dst); 2171 err = 0; 2172 goto out; 2173 } 2174 } 2175 2176 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2177 flags | RTCF_LOCAL, res->type, 2178 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2179 if (!rth) 2180 goto e_nobufs; 2181 2182 rth->dst.output= ip_rt_bug; 2183 #ifdef CONFIG_IP_ROUTE_CLASSID 2184 rth->dst.tclassid = itag; 2185 #endif 2186 rth->rt_is_input = 1; 2187 2188 RT_CACHE_STAT_INC(in_slow_tot); 2189 if (res->type == RTN_UNREACHABLE) { 2190 rth->dst.input= ip_error; 2191 rth->dst.error= -err; 2192 rth->rt_flags &= ~RTCF_LOCAL; 2193 } 2194 2195 if (do_cache) { 2196 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2197 2198 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2199 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2200 WARN_ON(rth->dst.input == lwtunnel_input); 2201 rth->dst.lwtstate->orig_input = rth->dst.input; 2202 rth->dst.input = lwtunnel_input; 2203 } 2204 2205 if (unlikely(!rt_cache_route(nhc, rth))) 2206 rt_add_uncached_list(rth); 2207 } 2208 skb_dst_set(skb, &rth->dst); 2209 err = 0; 2210 goto out; 2211 2212 no_route: 2213 RT_CACHE_STAT_INC(in_no_route); 2214 res->type = RTN_UNREACHABLE; 2215 res->fi = NULL; 2216 res->table = NULL; 2217 goto local_input; 2218 2219 /* 2220 * Do not cache martian addresses: they should be logged (RFC1812) 2221 */ 2222 martian_destination: 2223 RT_CACHE_STAT_INC(in_martian_dst); 2224 #ifdef CONFIG_IP_ROUTE_VERBOSE 2225 if (IN_DEV_LOG_MARTIANS(in_dev)) 2226 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2227 &daddr, &saddr, dev->name); 2228 #endif 2229 2230 e_inval: 2231 err = -EINVAL; 2232 goto out; 2233 2234 e_nobufs: 2235 err = -ENOBUFS; 2236 goto out; 2237 2238 martian_source: 2239 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2240 goto out; 2241 } 2242 2243 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2244 u8 tos, struct net_device *dev) 2245 { 2246 struct fib_result res; 2247 int err; 2248 2249 tos &= IPTOS_RT_MASK; 2250 rcu_read_lock(); 2251 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2252 rcu_read_unlock(); 2253 2254 return err; 2255 } 2256 EXPORT_SYMBOL(ip_route_input_noref); 2257 2258 /* called with rcu_read_lock held */ 2259 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2260 u8 tos, struct net_device *dev, struct fib_result *res) 2261 { 2262 /* Multicast recognition logic is moved from route cache to here. 2263 The problem was that too many Ethernet cards have broken/missing 2264 hardware multicast filters :-( As result the host on multicasting 2265 network acquires a lot of useless route cache entries, sort of 2266 SDR messages from all the world. Now we try to get rid of them. 2267 Really, provided software IP multicast filter is organized 2268 reasonably (at least, hashed), it does not result in a slowdown 2269 comparing with route cache reject entries. 2270 Note, that multicast routers are not affected, because 2271 route cache entry is created eventually. 2272 */ 2273 if (ipv4_is_multicast(daddr)) { 2274 struct in_device *in_dev = __in_dev_get_rcu(dev); 2275 int our = 0; 2276 int err = -EINVAL; 2277 2278 if (!in_dev) 2279 return err; 2280 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2281 ip_hdr(skb)->protocol); 2282 2283 /* check l3 master if no match yet */ 2284 if (!our && netif_is_l3_slave(dev)) { 2285 struct in_device *l3_in_dev; 2286 2287 l3_in_dev = __in_dev_get_rcu(skb->dev); 2288 if (l3_in_dev) 2289 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2290 ip_hdr(skb)->protocol); 2291 } 2292 2293 if (our 2294 #ifdef CONFIG_IP_MROUTE 2295 || 2296 (!ipv4_is_local_multicast(daddr) && 2297 IN_DEV_MFORWARD(in_dev)) 2298 #endif 2299 ) { 2300 err = ip_route_input_mc(skb, daddr, saddr, 2301 tos, dev, our); 2302 } 2303 return err; 2304 } 2305 2306 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2307 } 2308 2309 /* called with rcu_read_lock() */ 2310 static struct rtable *__mkroute_output(const struct fib_result *res, 2311 const struct flowi4 *fl4, int orig_oif, 2312 struct net_device *dev_out, 2313 unsigned int flags) 2314 { 2315 struct fib_info *fi = res->fi; 2316 struct fib_nh_exception *fnhe; 2317 struct in_device *in_dev; 2318 u16 type = res->type; 2319 struct rtable *rth; 2320 bool do_cache; 2321 2322 in_dev = __in_dev_get_rcu(dev_out); 2323 if (!in_dev) 2324 return ERR_PTR(-EINVAL); 2325 2326 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2327 if (ipv4_is_loopback(fl4->saddr) && 2328 !(dev_out->flags & IFF_LOOPBACK) && 2329 !netif_is_l3_master(dev_out)) 2330 return ERR_PTR(-EINVAL); 2331 2332 if (ipv4_is_lbcast(fl4->daddr)) 2333 type = RTN_BROADCAST; 2334 else if (ipv4_is_multicast(fl4->daddr)) 2335 type = RTN_MULTICAST; 2336 else if (ipv4_is_zeronet(fl4->daddr)) 2337 return ERR_PTR(-EINVAL); 2338 2339 if (dev_out->flags & IFF_LOOPBACK) 2340 flags |= RTCF_LOCAL; 2341 2342 do_cache = true; 2343 if (type == RTN_BROADCAST) { 2344 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2345 fi = NULL; 2346 } else if (type == RTN_MULTICAST) { 2347 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2348 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2349 fl4->flowi4_proto)) 2350 flags &= ~RTCF_LOCAL; 2351 else 2352 do_cache = false; 2353 /* If multicast route do not exist use 2354 * default one, but do not gateway in this case. 2355 * Yes, it is hack. 2356 */ 2357 if (fi && res->prefixlen < 4) 2358 fi = NULL; 2359 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2360 (orig_oif != dev_out->ifindex)) { 2361 /* For local routes that require a particular output interface 2362 * we do not want to cache the result. Caching the result 2363 * causes incorrect behaviour when there are multiple source 2364 * addresses on the interface, the end result being that if the 2365 * intended recipient is waiting on that interface for the 2366 * packet he won't receive it because it will be delivered on 2367 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2368 * be set to the loopback interface as well. 2369 */ 2370 do_cache = false; 2371 } 2372 2373 fnhe = NULL; 2374 do_cache &= fi != NULL; 2375 if (fi) { 2376 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2377 struct rtable __rcu **prth; 2378 2379 fnhe = find_exception(nhc, fl4->daddr); 2380 if (!do_cache) 2381 goto add; 2382 if (fnhe) { 2383 prth = &fnhe->fnhe_rth_output; 2384 } else { 2385 if (unlikely(fl4->flowi4_flags & 2386 FLOWI_FLAG_KNOWN_NH && 2387 !(nhc->nhc_gw_family && 2388 nhc->nhc_scope == RT_SCOPE_LINK))) { 2389 do_cache = false; 2390 goto add; 2391 } 2392 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2393 } 2394 rth = rcu_dereference(*prth); 2395 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2396 return rth; 2397 } 2398 2399 add: 2400 rth = rt_dst_alloc(dev_out, flags, type, 2401 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2402 IN_DEV_CONF_GET(in_dev, NOXFRM), 2403 do_cache); 2404 if (!rth) 2405 return ERR_PTR(-ENOBUFS); 2406 2407 rth->rt_iif = orig_oif; 2408 2409 RT_CACHE_STAT_INC(out_slow_tot); 2410 2411 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2412 if (flags & RTCF_LOCAL && 2413 !(dev_out->flags & IFF_LOOPBACK)) { 2414 rth->dst.output = ip_mc_output; 2415 RT_CACHE_STAT_INC(out_slow_mc); 2416 } 2417 #ifdef CONFIG_IP_MROUTE 2418 if (type == RTN_MULTICAST) { 2419 if (IN_DEV_MFORWARD(in_dev) && 2420 !ipv4_is_local_multicast(fl4->daddr)) { 2421 rth->dst.input = ip_mr_input; 2422 rth->dst.output = ip_mc_output; 2423 } 2424 } 2425 #endif 2426 } 2427 2428 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2429 lwtunnel_set_redirect(&rth->dst); 2430 2431 return rth; 2432 } 2433 2434 /* 2435 * Major route resolver routine. 2436 */ 2437 2438 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2439 const struct sk_buff *skb) 2440 { 2441 __u8 tos = RT_FL_TOS(fl4); 2442 struct fib_result res = { 2443 .type = RTN_UNSPEC, 2444 .fi = NULL, 2445 .table = NULL, 2446 .tclassid = 0, 2447 }; 2448 struct rtable *rth; 2449 2450 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2451 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2452 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2453 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2454 2455 rcu_read_lock(); 2456 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2457 rcu_read_unlock(); 2458 2459 return rth; 2460 } 2461 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2462 2463 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2464 struct fib_result *res, 2465 const struct sk_buff *skb) 2466 { 2467 struct net_device *dev_out = NULL; 2468 int orig_oif = fl4->flowi4_oif; 2469 unsigned int flags = 0; 2470 struct rtable *rth; 2471 int err = -ENETUNREACH; 2472 2473 if (fl4->saddr) { 2474 rth = ERR_PTR(-EINVAL); 2475 if (ipv4_is_multicast(fl4->saddr) || 2476 ipv4_is_lbcast(fl4->saddr) || 2477 ipv4_is_zeronet(fl4->saddr)) 2478 goto out; 2479 2480 /* I removed check for oif == dev_out->oif here. 2481 It was wrong for two reasons: 2482 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2483 is assigned to multiple interfaces. 2484 2. Moreover, we are allowed to send packets with saddr 2485 of another iface. --ANK 2486 */ 2487 2488 if (fl4->flowi4_oif == 0 && 2489 (ipv4_is_multicast(fl4->daddr) || 2490 ipv4_is_lbcast(fl4->daddr))) { 2491 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2492 dev_out = __ip_dev_find(net, fl4->saddr, false); 2493 if (!dev_out) 2494 goto out; 2495 2496 /* Special hack: user can direct multicasts 2497 and limited broadcast via necessary interface 2498 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2499 This hack is not just for fun, it allows 2500 vic,vat and friends to work. 2501 They bind socket to loopback, set ttl to zero 2502 and expect that it will work. 2503 From the viewpoint of routing cache they are broken, 2504 because we are not allowed to build multicast path 2505 with loopback source addr (look, routing cache 2506 cannot know, that ttl is zero, so that packet 2507 will not leave this host and route is valid). 2508 Luckily, this hack is good workaround. 2509 */ 2510 2511 fl4->flowi4_oif = dev_out->ifindex; 2512 goto make_route; 2513 } 2514 2515 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2516 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2517 if (!__ip_dev_find(net, fl4->saddr, false)) 2518 goto out; 2519 } 2520 } 2521 2522 2523 if (fl4->flowi4_oif) { 2524 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2525 rth = ERR_PTR(-ENODEV); 2526 if (!dev_out) 2527 goto out; 2528 2529 /* RACE: Check return value of inet_select_addr instead. */ 2530 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2531 rth = ERR_PTR(-ENETUNREACH); 2532 goto out; 2533 } 2534 if (ipv4_is_local_multicast(fl4->daddr) || 2535 ipv4_is_lbcast(fl4->daddr) || 2536 fl4->flowi4_proto == IPPROTO_IGMP) { 2537 if (!fl4->saddr) 2538 fl4->saddr = inet_select_addr(dev_out, 0, 2539 RT_SCOPE_LINK); 2540 goto make_route; 2541 } 2542 if (!fl4->saddr) { 2543 if (ipv4_is_multicast(fl4->daddr)) 2544 fl4->saddr = inet_select_addr(dev_out, 0, 2545 fl4->flowi4_scope); 2546 else if (!fl4->daddr) 2547 fl4->saddr = inet_select_addr(dev_out, 0, 2548 RT_SCOPE_HOST); 2549 } 2550 } 2551 2552 if (!fl4->daddr) { 2553 fl4->daddr = fl4->saddr; 2554 if (!fl4->daddr) 2555 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2556 dev_out = net->loopback_dev; 2557 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2558 res->type = RTN_LOCAL; 2559 flags |= RTCF_LOCAL; 2560 goto make_route; 2561 } 2562 2563 err = fib_lookup(net, fl4, res, 0); 2564 if (err) { 2565 res->fi = NULL; 2566 res->table = NULL; 2567 if (fl4->flowi4_oif && 2568 (ipv4_is_multicast(fl4->daddr) || 2569 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2570 /* Apparently, routing tables are wrong. Assume, 2571 that the destination is on link. 2572 2573 WHY? DW. 2574 Because we are allowed to send to iface 2575 even if it has NO routes and NO assigned 2576 addresses. When oif is specified, routing 2577 tables are looked up with only one purpose: 2578 to catch if destination is gatewayed, rather than 2579 direct. Moreover, if MSG_DONTROUTE is set, 2580 we send packet, ignoring both routing tables 2581 and ifaddr state. --ANK 2582 2583 2584 We could make it even if oif is unknown, 2585 likely IPv6, but we do not. 2586 */ 2587 2588 if (fl4->saddr == 0) 2589 fl4->saddr = inet_select_addr(dev_out, 0, 2590 RT_SCOPE_LINK); 2591 res->type = RTN_UNICAST; 2592 goto make_route; 2593 } 2594 rth = ERR_PTR(err); 2595 goto out; 2596 } 2597 2598 if (res->type == RTN_LOCAL) { 2599 if (!fl4->saddr) { 2600 if (res->fi->fib_prefsrc) 2601 fl4->saddr = res->fi->fib_prefsrc; 2602 else 2603 fl4->saddr = fl4->daddr; 2604 } 2605 2606 /* L3 master device is the loopback for that domain */ 2607 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2608 net->loopback_dev; 2609 2610 /* make sure orig_oif points to fib result device even 2611 * though packet rx/tx happens over loopback or l3mdev 2612 */ 2613 orig_oif = FIB_RES_OIF(*res); 2614 2615 fl4->flowi4_oif = dev_out->ifindex; 2616 flags |= RTCF_LOCAL; 2617 goto make_route; 2618 } 2619 2620 fib_select_path(net, res, fl4, skb); 2621 2622 dev_out = FIB_RES_DEV(*res); 2623 fl4->flowi4_oif = dev_out->ifindex; 2624 2625 2626 make_route: 2627 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2628 2629 out: 2630 return rth; 2631 } 2632 2633 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2634 { 2635 return NULL; 2636 } 2637 2638 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2639 { 2640 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2641 2642 return mtu ? : dst->dev->mtu; 2643 } 2644 2645 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2646 struct sk_buff *skb, u32 mtu) 2647 { 2648 } 2649 2650 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2651 struct sk_buff *skb) 2652 { 2653 } 2654 2655 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2656 unsigned long old) 2657 { 2658 return NULL; 2659 } 2660 2661 static struct dst_ops ipv4_dst_blackhole_ops = { 2662 .family = AF_INET, 2663 .check = ipv4_blackhole_dst_check, 2664 .mtu = ipv4_blackhole_mtu, 2665 .default_advmss = ipv4_default_advmss, 2666 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2667 .redirect = ipv4_rt_blackhole_redirect, 2668 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2669 .neigh_lookup = ipv4_neigh_lookup, 2670 }; 2671 2672 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2673 { 2674 struct rtable *ort = (struct rtable *) dst_orig; 2675 struct rtable *rt; 2676 2677 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2678 if (rt) { 2679 struct dst_entry *new = &rt->dst; 2680 2681 new->__use = 1; 2682 new->input = dst_discard; 2683 new->output = dst_discard_out; 2684 2685 new->dev = net->loopback_dev; 2686 if (new->dev) 2687 dev_hold(new->dev); 2688 2689 rt->rt_is_input = ort->rt_is_input; 2690 rt->rt_iif = ort->rt_iif; 2691 rt->rt_pmtu = ort->rt_pmtu; 2692 rt->rt_mtu_locked = ort->rt_mtu_locked; 2693 2694 rt->rt_genid = rt_genid_ipv4(net); 2695 rt->rt_flags = ort->rt_flags; 2696 rt->rt_type = ort->rt_type; 2697 rt->rt_gw_family = ort->rt_gw_family; 2698 if (rt->rt_gw_family == AF_INET) 2699 rt->rt_gw4 = ort->rt_gw4; 2700 else if (rt->rt_gw_family == AF_INET6) 2701 rt->rt_gw6 = ort->rt_gw6; 2702 2703 INIT_LIST_HEAD(&rt->rt_uncached); 2704 } 2705 2706 dst_release(dst_orig); 2707 2708 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2709 } 2710 2711 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2712 const struct sock *sk) 2713 { 2714 struct rtable *rt = __ip_route_output_key(net, flp4); 2715 2716 if (IS_ERR(rt)) 2717 return rt; 2718 2719 if (flp4->flowi4_proto) 2720 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2721 flowi4_to_flowi(flp4), 2722 sk, 0); 2723 2724 return rt; 2725 } 2726 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2727 2728 /* called with rcu_read_lock held */ 2729 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2730 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2731 struct sk_buff *skb, u32 portid, u32 seq) 2732 { 2733 struct rtmsg *r; 2734 struct nlmsghdr *nlh; 2735 unsigned long expires = 0; 2736 u32 error; 2737 u32 metrics[RTAX_MAX]; 2738 2739 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0); 2740 if (!nlh) 2741 return -EMSGSIZE; 2742 2743 r = nlmsg_data(nlh); 2744 r->rtm_family = AF_INET; 2745 r->rtm_dst_len = 32; 2746 r->rtm_src_len = 0; 2747 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2748 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2749 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2750 goto nla_put_failure; 2751 r->rtm_type = rt->rt_type; 2752 r->rtm_scope = RT_SCOPE_UNIVERSE; 2753 r->rtm_protocol = RTPROT_UNSPEC; 2754 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2755 if (rt->rt_flags & RTCF_NOTIFY) 2756 r->rtm_flags |= RTM_F_NOTIFY; 2757 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2758 r->rtm_flags |= RTCF_DOREDIRECT; 2759 2760 if (nla_put_in_addr(skb, RTA_DST, dst)) 2761 goto nla_put_failure; 2762 if (src) { 2763 r->rtm_src_len = 32; 2764 if (nla_put_in_addr(skb, RTA_SRC, src)) 2765 goto nla_put_failure; 2766 } 2767 if (rt->dst.dev && 2768 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2769 goto nla_put_failure; 2770 #ifdef CONFIG_IP_ROUTE_CLASSID 2771 if (rt->dst.tclassid && 2772 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2773 goto nla_put_failure; 2774 #endif 2775 if (fl4 && !rt_is_input_route(rt) && 2776 fl4->saddr != src) { 2777 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2778 goto nla_put_failure; 2779 } 2780 if (rt->rt_gw_family == AF_INET && 2781 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2782 goto nla_put_failure; 2783 } else if (rt->rt_gw_family == AF_INET6) { 2784 int alen = sizeof(struct in6_addr); 2785 struct nlattr *nla; 2786 struct rtvia *via; 2787 2788 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2789 if (!nla) 2790 goto nla_put_failure; 2791 2792 via = nla_data(nla); 2793 via->rtvia_family = AF_INET6; 2794 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2795 } 2796 2797 expires = rt->dst.expires; 2798 if (expires) { 2799 unsigned long now = jiffies; 2800 2801 if (time_before(now, expires)) 2802 expires -= now; 2803 else 2804 expires = 0; 2805 } 2806 2807 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2808 if (rt->rt_pmtu && expires) 2809 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2810 if (rt->rt_mtu_locked && expires) 2811 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2812 if (rtnetlink_put_metrics(skb, metrics) < 0) 2813 goto nla_put_failure; 2814 2815 if (fl4) { 2816 if (fl4->flowi4_mark && 2817 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2818 goto nla_put_failure; 2819 2820 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2821 nla_put_u32(skb, RTA_UID, 2822 from_kuid_munged(current_user_ns(), 2823 fl4->flowi4_uid))) 2824 goto nla_put_failure; 2825 2826 if (rt_is_input_route(rt)) { 2827 #ifdef CONFIG_IP_MROUTE 2828 if (ipv4_is_multicast(dst) && 2829 !ipv4_is_local_multicast(dst) && 2830 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2831 int err = ipmr_get_route(net, skb, 2832 fl4->saddr, fl4->daddr, 2833 r, portid); 2834 2835 if (err <= 0) { 2836 if (err == 0) 2837 return 0; 2838 goto nla_put_failure; 2839 } 2840 } else 2841 #endif 2842 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2843 goto nla_put_failure; 2844 } 2845 } 2846 2847 error = rt->dst.error; 2848 2849 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2850 goto nla_put_failure; 2851 2852 nlmsg_end(skb, nlh); 2853 return 0; 2854 2855 nla_put_failure: 2856 nlmsg_cancel(skb, nlh); 2857 return -EMSGSIZE; 2858 } 2859 2860 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2861 struct netlink_callback *cb, u32 table_id, 2862 struct fnhe_hash_bucket *bucket, int genid, 2863 int *fa_index, int fa_start) 2864 { 2865 int i; 2866 2867 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2868 struct fib_nh_exception *fnhe; 2869 2870 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2871 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2872 struct rtable *rt; 2873 int err; 2874 2875 if (*fa_index < fa_start) 2876 goto next; 2877 2878 if (fnhe->fnhe_genid != genid) 2879 goto next; 2880 2881 if (fnhe->fnhe_expires && 2882 time_after(jiffies, fnhe->fnhe_expires)) 2883 goto next; 2884 2885 rt = rcu_dereference(fnhe->fnhe_rth_input); 2886 if (!rt) 2887 rt = rcu_dereference(fnhe->fnhe_rth_output); 2888 if (!rt) 2889 goto next; 2890 2891 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2892 table_id, NULL, skb, 2893 NETLINK_CB(cb->skb).portid, 2894 cb->nlh->nlmsg_seq); 2895 if (err) 2896 return err; 2897 next: 2898 (*fa_index)++; 2899 } 2900 } 2901 2902 return 0; 2903 } 2904 2905 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2906 u32 table_id, struct fib_info *fi, 2907 int *fa_index, int fa_start) 2908 { 2909 struct net *net = sock_net(cb->skb->sk); 2910 int nhsel, genid = fnhe_genid(net); 2911 2912 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2913 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2914 struct fnhe_hash_bucket *bucket; 2915 int err; 2916 2917 if (nhc->nhc_flags & RTNH_F_DEAD) 2918 continue; 2919 2920 rcu_read_lock(); 2921 bucket = rcu_dereference(nhc->nhc_exceptions); 2922 err = 0; 2923 if (bucket) 2924 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 2925 genid, fa_index, fa_start); 2926 rcu_read_unlock(); 2927 if (err) 2928 return err; 2929 } 2930 2931 return 0; 2932 } 2933 2934 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 2935 u8 ip_proto, __be16 sport, 2936 __be16 dport) 2937 { 2938 struct sk_buff *skb; 2939 struct iphdr *iph; 2940 2941 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2942 if (!skb) 2943 return NULL; 2944 2945 /* Reserve room for dummy headers, this skb can pass 2946 * through good chunk of routing engine. 2947 */ 2948 skb_reset_mac_header(skb); 2949 skb_reset_network_header(skb); 2950 skb->protocol = htons(ETH_P_IP); 2951 iph = skb_put(skb, sizeof(struct iphdr)); 2952 iph->protocol = ip_proto; 2953 iph->saddr = src; 2954 iph->daddr = dst; 2955 iph->version = 0x4; 2956 iph->frag_off = 0; 2957 iph->ihl = 0x5; 2958 skb_set_transport_header(skb, skb->len); 2959 2960 switch (iph->protocol) { 2961 case IPPROTO_UDP: { 2962 struct udphdr *udph; 2963 2964 udph = skb_put_zero(skb, sizeof(struct udphdr)); 2965 udph->source = sport; 2966 udph->dest = dport; 2967 udph->len = sizeof(struct udphdr); 2968 udph->check = 0; 2969 break; 2970 } 2971 case IPPROTO_TCP: { 2972 struct tcphdr *tcph; 2973 2974 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 2975 tcph->source = sport; 2976 tcph->dest = dport; 2977 tcph->doff = sizeof(struct tcphdr) / 4; 2978 tcph->rst = 1; 2979 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 2980 src, dst, 0); 2981 break; 2982 } 2983 case IPPROTO_ICMP: { 2984 struct icmphdr *icmph; 2985 2986 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 2987 icmph->type = ICMP_ECHO; 2988 icmph->code = 0; 2989 } 2990 } 2991 2992 return skb; 2993 } 2994 2995 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 2996 const struct nlmsghdr *nlh, 2997 struct nlattr **tb, 2998 struct netlink_ext_ack *extack) 2999 { 3000 struct rtmsg *rtm; 3001 int i, err; 3002 3003 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3004 NL_SET_ERR_MSG(extack, 3005 "ipv4: Invalid header for route get request"); 3006 return -EINVAL; 3007 } 3008 3009 if (!netlink_strict_get_check(skb)) 3010 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3011 rtm_ipv4_policy, extack); 3012 3013 rtm = nlmsg_data(nlh); 3014 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3015 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3016 rtm->rtm_table || rtm->rtm_protocol || 3017 rtm->rtm_scope || rtm->rtm_type) { 3018 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3019 return -EINVAL; 3020 } 3021 3022 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3023 RTM_F_LOOKUP_TABLE | 3024 RTM_F_FIB_MATCH)) { 3025 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3026 return -EINVAL; 3027 } 3028 3029 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3030 rtm_ipv4_policy, extack); 3031 if (err) 3032 return err; 3033 3034 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3035 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3036 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3037 return -EINVAL; 3038 } 3039 3040 for (i = 0; i <= RTA_MAX; i++) { 3041 if (!tb[i]) 3042 continue; 3043 3044 switch (i) { 3045 case RTA_IIF: 3046 case RTA_OIF: 3047 case RTA_SRC: 3048 case RTA_DST: 3049 case RTA_IP_PROTO: 3050 case RTA_SPORT: 3051 case RTA_DPORT: 3052 case RTA_MARK: 3053 case RTA_UID: 3054 break; 3055 default: 3056 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3057 return -EINVAL; 3058 } 3059 } 3060 3061 return 0; 3062 } 3063 3064 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3065 struct netlink_ext_ack *extack) 3066 { 3067 struct net *net = sock_net(in_skb->sk); 3068 struct nlattr *tb[RTA_MAX+1]; 3069 u32 table_id = RT_TABLE_MAIN; 3070 __be16 sport = 0, dport = 0; 3071 struct fib_result res = {}; 3072 u8 ip_proto = IPPROTO_UDP; 3073 struct rtable *rt = NULL; 3074 struct sk_buff *skb; 3075 struct rtmsg *rtm; 3076 struct flowi4 fl4 = {}; 3077 __be32 dst = 0; 3078 __be32 src = 0; 3079 kuid_t uid; 3080 u32 iif; 3081 int err; 3082 int mark; 3083 3084 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3085 if (err < 0) 3086 return err; 3087 3088 rtm = nlmsg_data(nlh); 3089 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3090 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3091 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3092 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3093 if (tb[RTA_UID]) 3094 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3095 else 3096 uid = (iif ? INVALID_UID : current_uid()); 3097 3098 if (tb[RTA_IP_PROTO]) { 3099 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3100 &ip_proto, AF_INET, extack); 3101 if (err) 3102 return err; 3103 } 3104 3105 if (tb[RTA_SPORT]) 3106 sport = nla_get_be16(tb[RTA_SPORT]); 3107 3108 if (tb[RTA_DPORT]) 3109 dport = nla_get_be16(tb[RTA_DPORT]); 3110 3111 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3112 if (!skb) 3113 return -ENOBUFS; 3114 3115 fl4.daddr = dst; 3116 fl4.saddr = src; 3117 fl4.flowi4_tos = rtm->rtm_tos; 3118 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3119 fl4.flowi4_mark = mark; 3120 fl4.flowi4_uid = uid; 3121 if (sport) 3122 fl4.fl4_sport = sport; 3123 if (dport) 3124 fl4.fl4_dport = dport; 3125 fl4.flowi4_proto = ip_proto; 3126 3127 rcu_read_lock(); 3128 3129 if (iif) { 3130 struct net_device *dev; 3131 3132 dev = dev_get_by_index_rcu(net, iif); 3133 if (!dev) { 3134 err = -ENODEV; 3135 goto errout_rcu; 3136 } 3137 3138 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3139 skb->dev = dev; 3140 skb->mark = mark; 3141 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 3142 dev, &res); 3143 3144 rt = skb_rtable(skb); 3145 if (err == 0 && rt->dst.error) 3146 err = -rt->dst.error; 3147 } else { 3148 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3149 skb->dev = net->loopback_dev; 3150 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3151 err = 0; 3152 if (IS_ERR(rt)) 3153 err = PTR_ERR(rt); 3154 else 3155 skb_dst_set(skb, &rt->dst); 3156 } 3157 3158 if (err) 3159 goto errout_rcu; 3160 3161 if (rtm->rtm_flags & RTM_F_NOTIFY) 3162 rt->rt_flags |= RTCF_NOTIFY; 3163 3164 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3165 table_id = res.table ? res.table->tb_id : 0; 3166 3167 /* reset skb for netlink reply msg */ 3168 skb_trim(skb, 0); 3169 skb_reset_network_header(skb); 3170 skb_reset_transport_header(skb); 3171 skb_reset_mac_header(skb); 3172 3173 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3174 if (!res.fi) { 3175 err = fib_props[res.type].error; 3176 if (!err) 3177 err = -EHOSTUNREACH; 3178 goto errout_rcu; 3179 } 3180 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3181 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 3182 rt->rt_type, res.prefix, res.prefixlen, 3183 fl4.flowi4_tos, res.fi, 0); 3184 } else { 3185 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3186 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq); 3187 } 3188 if (err < 0) 3189 goto errout_rcu; 3190 3191 rcu_read_unlock(); 3192 3193 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3194 3195 errout_free: 3196 return err; 3197 errout_rcu: 3198 rcu_read_unlock(); 3199 kfree_skb(skb); 3200 goto errout_free; 3201 } 3202 3203 void ip_rt_multicast_event(struct in_device *in_dev) 3204 { 3205 rt_cache_flush(dev_net(in_dev->dev)); 3206 } 3207 3208 #ifdef CONFIG_SYSCTL 3209 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3210 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3211 static int ip_rt_gc_elasticity __read_mostly = 8; 3212 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3213 3214 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3215 void __user *buffer, 3216 size_t *lenp, loff_t *ppos) 3217 { 3218 struct net *net = (struct net *)__ctl->extra1; 3219 3220 if (write) { 3221 rt_cache_flush(net); 3222 fnhe_genid_bump(net); 3223 return 0; 3224 } 3225 3226 return -EINVAL; 3227 } 3228 3229 static struct ctl_table ipv4_route_table[] = { 3230 { 3231 .procname = "gc_thresh", 3232 .data = &ipv4_dst_ops.gc_thresh, 3233 .maxlen = sizeof(int), 3234 .mode = 0644, 3235 .proc_handler = proc_dointvec, 3236 }, 3237 { 3238 .procname = "max_size", 3239 .data = &ip_rt_max_size, 3240 .maxlen = sizeof(int), 3241 .mode = 0644, 3242 .proc_handler = proc_dointvec, 3243 }, 3244 { 3245 /* Deprecated. Use gc_min_interval_ms */ 3246 3247 .procname = "gc_min_interval", 3248 .data = &ip_rt_gc_min_interval, 3249 .maxlen = sizeof(int), 3250 .mode = 0644, 3251 .proc_handler = proc_dointvec_jiffies, 3252 }, 3253 { 3254 .procname = "gc_min_interval_ms", 3255 .data = &ip_rt_gc_min_interval, 3256 .maxlen = sizeof(int), 3257 .mode = 0644, 3258 .proc_handler = proc_dointvec_ms_jiffies, 3259 }, 3260 { 3261 .procname = "gc_timeout", 3262 .data = &ip_rt_gc_timeout, 3263 .maxlen = sizeof(int), 3264 .mode = 0644, 3265 .proc_handler = proc_dointvec_jiffies, 3266 }, 3267 { 3268 .procname = "gc_interval", 3269 .data = &ip_rt_gc_interval, 3270 .maxlen = sizeof(int), 3271 .mode = 0644, 3272 .proc_handler = proc_dointvec_jiffies, 3273 }, 3274 { 3275 .procname = "redirect_load", 3276 .data = &ip_rt_redirect_load, 3277 .maxlen = sizeof(int), 3278 .mode = 0644, 3279 .proc_handler = proc_dointvec, 3280 }, 3281 { 3282 .procname = "redirect_number", 3283 .data = &ip_rt_redirect_number, 3284 .maxlen = sizeof(int), 3285 .mode = 0644, 3286 .proc_handler = proc_dointvec, 3287 }, 3288 { 3289 .procname = "redirect_silence", 3290 .data = &ip_rt_redirect_silence, 3291 .maxlen = sizeof(int), 3292 .mode = 0644, 3293 .proc_handler = proc_dointvec, 3294 }, 3295 { 3296 .procname = "error_cost", 3297 .data = &ip_rt_error_cost, 3298 .maxlen = sizeof(int), 3299 .mode = 0644, 3300 .proc_handler = proc_dointvec, 3301 }, 3302 { 3303 .procname = "error_burst", 3304 .data = &ip_rt_error_burst, 3305 .maxlen = sizeof(int), 3306 .mode = 0644, 3307 .proc_handler = proc_dointvec, 3308 }, 3309 { 3310 .procname = "gc_elasticity", 3311 .data = &ip_rt_gc_elasticity, 3312 .maxlen = sizeof(int), 3313 .mode = 0644, 3314 .proc_handler = proc_dointvec, 3315 }, 3316 { 3317 .procname = "mtu_expires", 3318 .data = &ip_rt_mtu_expires, 3319 .maxlen = sizeof(int), 3320 .mode = 0644, 3321 .proc_handler = proc_dointvec_jiffies, 3322 }, 3323 { 3324 .procname = "min_pmtu", 3325 .data = &ip_rt_min_pmtu, 3326 .maxlen = sizeof(int), 3327 .mode = 0644, 3328 .proc_handler = proc_dointvec_minmax, 3329 .extra1 = &ip_min_valid_pmtu, 3330 }, 3331 { 3332 .procname = "min_adv_mss", 3333 .data = &ip_rt_min_advmss, 3334 .maxlen = sizeof(int), 3335 .mode = 0644, 3336 .proc_handler = proc_dointvec, 3337 }, 3338 { } 3339 }; 3340 3341 static const char ipv4_route_flush_procname[] = "flush"; 3342 3343 static struct ctl_table ipv4_route_flush_table[] = { 3344 { 3345 .procname = ipv4_route_flush_procname, 3346 .maxlen = sizeof(int), 3347 .mode = 0200, 3348 .proc_handler = ipv4_sysctl_rtcache_flush, 3349 }, 3350 { }, 3351 }; 3352 3353 static __net_init int sysctl_route_net_init(struct net *net) 3354 { 3355 struct ctl_table *tbl; 3356 3357 tbl = ipv4_route_flush_table; 3358 if (!net_eq(net, &init_net)) { 3359 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3360 if (!tbl) 3361 goto err_dup; 3362 3363 /* Don't export non-whitelisted sysctls to unprivileged users */ 3364 if (net->user_ns != &init_user_ns) { 3365 if (tbl[0].procname != ipv4_route_flush_procname) 3366 tbl[0].procname = NULL; 3367 } 3368 } 3369 tbl[0].extra1 = net; 3370 3371 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3372 if (!net->ipv4.route_hdr) 3373 goto err_reg; 3374 return 0; 3375 3376 err_reg: 3377 if (tbl != ipv4_route_flush_table) 3378 kfree(tbl); 3379 err_dup: 3380 return -ENOMEM; 3381 } 3382 3383 static __net_exit void sysctl_route_net_exit(struct net *net) 3384 { 3385 struct ctl_table *tbl; 3386 3387 tbl = net->ipv4.route_hdr->ctl_table_arg; 3388 unregister_net_sysctl_table(net->ipv4.route_hdr); 3389 BUG_ON(tbl == ipv4_route_flush_table); 3390 kfree(tbl); 3391 } 3392 3393 static __net_initdata struct pernet_operations sysctl_route_ops = { 3394 .init = sysctl_route_net_init, 3395 .exit = sysctl_route_net_exit, 3396 }; 3397 #endif 3398 3399 static __net_init int rt_genid_init(struct net *net) 3400 { 3401 atomic_set(&net->ipv4.rt_genid, 0); 3402 atomic_set(&net->fnhe_genid, 0); 3403 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3404 return 0; 3405 } 3406 3407 static __net_initdata struct pernet_operations rt_genid_ops = { 3408 .init = rt_genid_init, 3409 }; 3410 3411 static int __net_init ipv4_inetpeer_init(struct net *net) 3412 { 3413 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3414 3415 if (!bp) 3416 return -ENOMEM; 3417 inet_peer_base_init(bp); 3418 net->ipv4.peers = bp; 3419 return 0; 3420 } 3421 3422 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3423 { 3424 struct inet_peer_base *bp = net->ipv4.peers; 3425 3426 net->ipv4.peers = NULL; 3427 inetpeer_invalidate_tree(bp); 3428 kfree(bp); 3429 } 3430 3431 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3432 .init = ipv4_inetpeer_init, 3433 .exit = ipv4_inetpeer_exit, 3434 }; 3435 3436 #ifdef CONFIG_IP_ROUTE_CLASSID 3437 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3438 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3439 3440 int __init ip_rt_init(void) 3441 { 3442 int cpu; 3443 3444 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents), 3445 GFP_KERNEL); 3446 if (!ip_idents) 3447 panic("IP: failed to allocate ip_idents\n"); 3448 3449 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3450 3451 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3452 if (!ip_tstamps) 3453 panic("IP: failed to allocate ip_tstamps\n"); 3454 3455 for_each_possible_cpu(cpu) { 3456 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3457 3458 INIT_LIST_HEAD(&ul->head); 3459 spin_lock_init(&ul->lock); 3460 } 3461 #ifdef CONFIG_IP_ROUTE_CLASSID 3462 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3463 if (!ip_rt_acct) 3464 panic("IP: failed to allocate ip_rt_acct\n"); 3465 #endif 3466 3467 ipv4_dst_ops.kmem_cachep = 3468 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3469 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3470 3471 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3472 3473 if (dst_entries_init(&ipv4_dst_ops) < 0) 3474 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3475 3476 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3477 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3478 3479 ipv4_dst_ops.gc_thresh = ~0; 3480 ip_rt_max_size = INT_MAX; 3481 3482 devinet_init(); 3483 ip_fib_init(); 3484 3485 if (ip_rt_proc_init()) 3486 pr_err("Unable to create route proc files\n"); 3487 #ifdef CONFIG_XFRM 3488 xfrm_init(); 3489 xfrm4_init(); 3490 #endif 3491 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3492 RTNL_FLAG_DOIT_UNLOCKED); 3493 3494 #ifdef CONFIG_SYSCTL 3495 register_pernet_subsys(&sysctl_route_ops); 3496 #endif 3497 register_pernet_subsys(&rt_genid_ops); 3498 register_pernet_subsys(&ipv4_inetpeer_ops); 3499 return 0; 3500 } 3501 3502 #ifdef CONFIG_SYSCTL 3503 /* 3504 * We really need to sanitize the damn ipv4 init order, then all 3505 * this nonsense will go away. 3506 */ 3507 void __init ip_static_sysctl_init(void) 3508 { 3509 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3510 } 3511 #endif 3512