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 bool confirm_neigh); 144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 145 struct sk_buff *skb); 146 static void ipv4_dst_destroy(struct dst_entry *dst); 147 148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 149 { 150 WARN_ON(1); 151 return NULL; 152 } 153 154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 155 struct sk_buff *skb, 156 const void *daddr); 157 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 158 159 static struct dst_ops ipv4_dst_ops = { 160 .family = AF_INET, 161 .check = ipv4_dst_check, 162 .default_advmss = ipv4_default_advmss, 163 .mtu = ipv4_mtu, 164 .cow_metrics = ipv4_cow_metrics, 165 .destroy = ipv4_dst_destroy, 166 .negative_advice = ipv4_negative_advice, 167 .link_failure = ipv4_link_failure, 168 .update_pmtu = ip_rt_update_pmtu, 169 .redirect = ip_do_redirect, 170 .local_out = __ip_local_out, 171 .neigh_lookup = ipv4_neigh_lookup, 172 .confirm_neigh = ipv4_confirm_neigh, 173 }; 174 175 #define ECN_OR_COST(class) TC_PRIO_##class 176 177 const __u8 ip_tos2prio[16] = { 178 TC_PRIO_BESTEFFORT, 179 ECN_OR_COST(BESTEFFORT), 180 TC_PRIO_BESTEFFORT, 181 ECN_OR_COST(BESTEFFORT), 182 TC_PRIO_BULK, 183 ECN_OR_COST(BULK), 184 TC_PRIO_BULK, 185 ECN_OR_COST(BULK), 186 TC_PRIO_INTERACTIVE, 187 ECN_OR_COST(INTERACTIVE), 188 TC_PRIO_INTERACTIVE, 189 ECN_OR_COST(INTERACTIVE), 190 TC_PRIO_INTERACTIVE_BULK, 191 ECN_OR_COST(INTERACTIVE_BULK), 192 TC_PRIO_INTERACTIVE_BULK, 193 ECN_OR_COST(INTERACTIVE_BULK) 194 }; 195 EXPORT_SYMBOL(ip_tos2prio); 196 197 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 198 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 199 200 #ifdef CONFIG_PROC_FS 201 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 202 { 203 if (*pos) 204 return NULL; 205 return SEQ_START_TOKEN; 206 } 207 208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 209 { 210 ++*pos; 211 return NULL; 212 } 213 214 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 215 { 216 } 217 218 static int rt_cache_seq_show(struct seq_file *seq, void *v) 219 { 220 if (v == SEQ_START_TOKEN) 221 seq_printf(seq, "%-127s\n", 222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 224 "HHUptod\tSpecDst"); 225 return 0; 226 } 227 228 static const struct seq_operations rt_cache_seq_ops = { 229 .start = rt_cache_seq_start, 230 .next = rt_cache_seq_next, 231 .stop = rt_cache_seq_stop, 232 .show = rt_cache_seq_show, 233 }; 234 235 static int rt_cache_seq_open(struct inode *inode, struct file *file) 236 { 237 return seq_open(file, &rt_cache_seq_ops); 238 } 239 240 static const struct proc_ops rt_cache_proc_ops = { 241 .proc_open = rt_cache_seq_open, 242 .proc_read = seq_read, 243 .proc_lseek = seq_lseek, 244 .proc_release = seq_release, 245 }; 246 247 248 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 249 { 250 int cpu; 251 252 if (*pos == 0) 253 return SEQ_START_TOKEN; 254 255 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 256 if (!cpu_possible(cpu)) 257 continue; 258 *pos = cpu+1; 259 return &per_cpu(rt_cache_stat, cpu); 260 } 261 return NULL; 262 } 263 264 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 265 { 266 int cpu; 267 268 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 269 if (!cpu_possible(cpu)) 270 continue; 271 *pos = cpu+1; 272 return &per_cpu(rt_cache_stat, cpu); 273 } 274 (*pos)++; 275 return NULL; 276 277 } 278 279 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 280 { 281 282 } 283 284 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 285 { 286 struct rt_cache_stat *st = v; 287 288 if (v == SEQ_START_TOKEN) { 289 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"); 290 return 0; 291 } 292 293 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 294 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 295 dst_entries_get_slow(&ipv4_dst_ops), 296 0, /* st->in_hit */ 297 st->in_slow_tot, 298 st->in_slow_mc, 299 st->in_no_route, 300 st->in_brd, 301 st->in_martian_dst, 302 st->in_martian_src, 303 304 0, /* st->out_hit */ 305 st->out_slow_tot, 306 st->out_slow_mc, 307 308 0, /* st->gc_total */ 309 0, /* st->gc_ignored */ 310 0, /* st->gc_goal_miss */ 311 0, /* st->gc_dst_overflow */ 312 0, /* st->in_hlist_search */ 313 0 /* st->out_hlist_search */ 314 ); 315 return 0; 316 } 317 318 static const struct seq_operations rt_cpu_seq_ops = { 319 .start = rt_cpu_seq_start, 320 .next = rt_cpu_seq_next, 321 .stop = rt_cpu_seq_stop, 322 .show = rt_cpu_seq_show, 323 }; 324 325 326 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 327 { 328 return seq_open(file, &rt_cpu_seq_ops); 329 } 330 331 static const struct proc_ops rt_cpu_proc_ops = { 332 .proc_open = rt_cpu_seq_open, 333 .proc_read = seq_read, 334 .proc_lseek = seq_lseek, 335 .proc_release = seq_release, 336 }; 337 338 #ifdef CONFIG_IP_ROUTE_CLASSID 339 static int rt_acct_proc_show(struct seq_file *m, void *v) 340 { 341 struct ip_rt_acct *dst, *src; 342 unsigned int i, j; 343 344 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 345 if (!dst) 346 return -ENOMEM; 347 348 for_each_possible_cpu(i) { 349 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 350 for (j = 0; j < 256; j++) { 351 dst[j].o_bytes += src[j].o_bytes; 352 dst[j].o_packets += src[j].o_packets; 353 dst[j].i_bytes += src[j].i_bytes; 354 dst[j].i_packets += src[j].i_packets; 355 } 356 } 357 358 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 359 kfree(dst); 360 return 0; 361 } 362 #endif 363 364 static int __net_init ip_rt_do_proc_init(struct net *net) 365 { 366 struct proc_dir_entry *pde; 367 368 pde = proc_create("rt_cache", 0444, net->proc_net, 369 &rt_cache_proc_ops); 370 if (!pde) 371 goto err1; 372 373 pde = proc_create("rt_cache", 0444, 374 net->proc_net_stat, &rt_cpu_proc_ops); 375 if (!pde) 376 goto err2; 377 378 #ifdef CONFIG_IP_ROUTE_CLASSID 379 pde = proc_create_single("rt_acct", 0, net->proc_net, 380 rt_acct_proc_show); 381 if (!pde) 382 goto err3; 383 #endif 384 return 0; 385 386 #ifdef CONFIG_IP_ROUTE_CLASSID 387 err3: 388 remove_proc_entry("rt_cache", net->proc_net_stat); 389 #endif 390 err2: 391 remove_proc_entry("rt_cache", net->proc_net); 392 err1: 393 return -ENOMEM; 394 } 395 396 static void __net_exit ip_rt_do_proc_exit(struct net *net) 397 { 398 remove_proc_entry("rt_cache", net->proc_net_stat); 399 remove_proc_entry("rt_cache", net->proc_net); 400 #ifdef CONFIG_IP_ROUTE_CLASSID 401 remove_proc_entry("rt_acct", net->proc_net); 402 #endif 403 } 404 405 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 406 .init = ip_rt_do_proc_init, 407 .exit = ip_rt_do_proc_exit, 408 }; 409 410 static int __init ip_rt_proc_init(void) 411 { 412 return register_pernet_subsys(&ip_rt_proc_ops); 413 } 414 415 #else 416 static inline int ip_rt_proc_init(void) 417 { 418 return 0; 419 } 420 #endif /* CONFIG_PROC_FS */ 421 422 static inline bool rt_is_expired(const struct rtable *rth) 423 { 424 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 425 } 426 427 void rt_cache_flush(struct net *net) 428 { 429 rt_genid_bump_ipv4(net); 430 } 431 432 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 433 struct sk_buff *skb, 434 const void *daddr) 435 { 436 const struct rtable *rt = container_of(dst, struct rtable, dst); 437 struct net_device *dev = dst->dev; 438 struct neighbour *n; 439 440 rcu_read_lock_bh(); 441 442 if (likely(rt->rt_gw_family == AF_INET)) { 443 n = ip_neigh_gw4(dev, rt->rt_gw4); 444 } else if (rt->rt_gw_family == AF_INET6) { 445 n = ip_neigh_gw6(dev, &rt->rt_gw6); 446 } else { 447 __be32 pkey; 448 449 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 450 n = ip_neigh_gw4(dev, pkey); 451 } 452 453 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 454 n = NULL; 455 456 rcu_read_unlock_bh(); 457 458 return n; 459 } 460 461 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 462 { 463 const struct rtable *rt = container_of(dst, struct rtable, dst); 464 struct net_device *dev = dst->dev; 465 const __be32 *pkey = daddr; 466 467 if (rt->rt_gw_family == AF_INET) { 468 pkey = (const __be32 *)&rt->rt_gw4; 469 } else if (rt->rt_gw_family == AF_INET6) { 470 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 471 } else if (!daddr || 472 (rt->rt_flags & 473 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 474 return; 475 } 476 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 477 } 478 479 #define IP_IDENTS_SZ 2048u 480 481 static atomic_t *ip_idents __read_mostly; 482 static u32 *ip_tstamps __read_mostly; 483 484 /* In order to protect privacy, we add a perturbation to identifiers 485 * if one generator is seldom used. This makes hard for an attacker 486 * to infer how many packets were sent between two points in time. 487 */ 488 u32 ip_idents_reserve(u32 hash, int segs) 489 { 490 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 491 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 492 u32 old = READ_ONCE(*p_tstamp); 493 u32 now = (u32)jiffies; 494 u32 new, delta = 0; 495 496 if (old != now && cmpxchg(p_tstamp, old, now) == old) 497 delta = prandom_u32_max(now - old); 498 499 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 500 do { 501 old = (u32)atomic_read(p_id); 502 new = old + delta + segs; 503 } while (atomic_cmpxchg(p_id, old, new) != old); 504 505 return new - segs; 506 } 507 EXPORT_SYMBOL(ip_idents_reserve); 508 509 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 510 { 511 u32 hash, id; 512 513 /* Note the following code is not safe, but this is okay. */ 514 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 515 get_random_bytes(&net->ipv4.ip_id_key, 516 sizeof(net->ipv4.ip_id_key)); 517 518 hash = siphash_3u32((__force u32)iph->daddr, 519 (__force u32)iph->saddr, 520 iph->protocol, 521 &net->ipv4.ip_id_key); 522 id = ip_idents_reserve(hash, segs); 523 iph->id = htons(id); 524 } 525 EXPORT_SYMBOL(__ip_select_ident); 526 527 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 528 const struct sock *sk, 529 const struct iphdr *iph, 530 int oif, u8 tos, 531 u8 prot, u32 mark, int flow_flags) 532 { 533 if (sk) { 534 const struct inet_sock *inet = inet_sk(sk); 535 536 oif = sk->sk_bound_dev_if; 537 mark = sk->sk_mark; 538 tos = RT_CONN_FLAGS(sk); 539 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 540 } 541 flowi4_init_output(fl4, oif, mark, tos, 542 RT_SCOPE_UNIVERSE, prot, 543 flow_flags, 544 iph->daddr, iph->saddr, 0, 0, 545 sock_net_uid(net, sk)); 546 } 547 548 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 549 const struct sock *sk) 550 { 551 const struct net *net = dev_net(skb->dev); 552 const struct iphdr *iph = ip_hdr(skb); 553 int oif = skb->dev->ifindex; 554 u8 tos = RT_TOS(iph->tos); 555 u8 prot = iph->protocol; 556 u32 mark = skb->mark; 557 558 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 559 } 560 561 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 562 { 563 const struct inet_sock *inet = inet_sk(sk); 564 const struct ip_options_rcu *inet_opt; 565 __be32 daddr = inet->inet_daddr; 566 567 rcu_read_lock(); 568 inet_opt = rcu_dereference(inet->inet_opt); 569 if (inet_opt && inet_opt->opt.srr) 570 daddr = inet_opt->opt.faddr; 571 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 572 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 573 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 574 inet_sk_flowi_flags(sk), 575 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 576 rcu_read_unlock(); 577 } 578 579 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 580 const struct sk_buff *skb) 581 { 582 if (skb) 583 build_skb_flow_key(fl4, skb, sk); 584 else 585 build_sk_flow_key(fl4, sk); 586 } 587 588 static DEFINE_SPINLOCK(fnhe_lock); 589 590 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 591 { 592 struct rtable *rt; 593 594 rt = rcu_dereference(fnhe->fnhe_rth_input); 595 if (rt) { 596 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 597 dst_dev_put(&rt->dst); 598 dst_release(&rt->dst); 599 } 600 rt = rcu_dereference(fnhe->fnhe_rth_output); 601 if (rt) { 602 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 603 dst_dev_put(&rt->dst); 604 dst_release(&rt->dst); 605 } 606 } 607 608 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 609 { 610 struct fib_nh_exception *fnhe, *oldest; 611 612 oldest = rcu_dereference(hash->chain); 613 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 614 fnhe = rcu_dereference(fnhe->fnhe_next)) { 615 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 616 oldest = fnhe; 617 } 618 fnhe_flush_routes(oldest); 619 return oldest; 620 } 621 622 static inline u32 fnhe_hashfun(__be32 daddr) 623 { 624 static u32 fnhe_hashrnd __read_mostly; 625 u32 hval; 626 627 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 628 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 629 return hash_32(hval, FNHE_HASH_SHIFT); 630 } 631 632 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 633 { 634 rt->rt_pmtu = fnhe->fnhe_pmtu; 635 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 636 rt->dst.expires = fnhe->fnhe_expires; 637 638 if (fnhe->fnhe_gw) { 639 rt->rt_flags |= RTCF_REDIRECTED; 640 rt->rt_uses_gateway = 1; 641 rt->rt_gw_family = AF_INET; 642 rt->rt_gw4 = fnhe->fnhe_gw; 643 } 644 } 645 646 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 647 __be32 gw, u32 pmtu, bool lock, 648 unsigned long expires) 649 { 650 struct fnhe_hash_bucket *hash; 651 struct fib_nh_exception *fnhe; 652 struct rtable *rt; 653 u32 genid, hval; 654 unsigned int i; 655 int depth; 656 657 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 658 hval = fnhe_hashfun(daddr); 659 660 spin_lock_bh(&fnhe_lock); 661 662 hash = rcu_dereference(nhc->nhc_exceptions); 663 if (!hash) { 664 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 665 if (!hash) 666 goto out_unlock; 667 rcu_assign_pointer(nhc->nhc_exceptions, hash); 668 } 669 670 hash += hval; 671 672 depth = 0; 673 for (fnhe = rcu_dereference(hash->chain); fnhe; 674 fnhe = rcu_dereference(fnhe->fnhe_next)) { 675 if (fnhe->fnhe_daddr == daddr) 676 break; 677 depth++; 678 } 679 680 if (fnhe) { 681 if (fnhe->fnhe_genid != genid) 682 fnhe->fnhe_genid = genid; 683 if (gw) 684 fnhe->fnhe_gw = gw; 685 if (pmtu) { 686 fnhe->fnhe_pmtu = pmtu; 687 fnhe->fnhe_mtu_locked = lock; 688 } 689 fnhe->fnhe_expires = max(1UL, expires); 690 /* Update all cached dsts too */ 691 rt = rcu_dereference(fnhe->fnhe_rth_input); 692 if (rt) 693 fill_route_from_fnhe(rt, fnhe); 694 rt = rcu_dereference(fnhe->fnhe_rth_output); 695 if (rt) 696 fill_route_from_fnhe(rt, fnhe); 697 } else { 698 if (depth > FNHE_RECLAIM_DEPTH) 699 fnhe = fnhe_oldest(hash); 700 else { 701 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 702 if (!fnhe) 703 goto out_unlock; 704 705 fnhe->fnhe_next = hash->chain; 706 rcu_assign_pointer(hash->chain, fnhe); 707 } 708 fnhe->fnhe_genid = genid; 709 fnhe->fnhe_daddr = daddr; 710 fnhe->fnhe_gw = gw; 711 fnhe->fnhe_pmtu = pmtu; 712 fnhe->fnhe_mtu_locked = lock; 713 fnhe->fnhe_expires = max(1UL, expires); 714 715 /* Exception created; mark the cached routes for the nexthop 716 * stale, so anyone caching it rechecks if this exception 717 * applies to them. 718 */ 719 rt = rcu_dereference(nhc->nhc_rth_input); 720 if (rt) 721 rt->dst.obsolete = DST_OBSOLETE_KILL; 722 723 for_each_possible_cpu(i) { 724 struct rtable __rcu **prt; 725 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 726 rt = rcu_dereference(*prt); 727 if (rt) 728 rt->dst.obsolete = DST_OBSOLETE_KILL; 729 } 730 } 731 732 fnhe->fnhe_stamp = jiffies; 733 734 out_unlock: 735 spin_unlock_bh(&fnhe_lock); 736 } 737 738 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 739 bool kill_route) 740 { 741 __be32 new_gw = icmp_hdr(skb)->un.gateway; 742 __be32 old_gw = ip_hdr(skb)->saddr; 743 struct net_device *dev = skb->dev; 744 struct in_device *in_dev; 745 struct fib_result res; 746 struct neighbour *n; 747 struct net *net; 748 749 switch (icmp_hdr(skb)->code & 7) { 750 case ICMP_REDIR_NET: 751 case ICMP_REDIR_NETTOS: 752 case ICMP_REDIR_HOST: 753 case ICMP_REDIR_HOSTTOS: 754 break; 755 756 default: 757 return; 758 } 759 760 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 761 return; 762 763 in_dev = __in_dev_get_rcu(dev); 764 if (!in_dev) 765 return; 766 767 net = dev_net(dev); 768 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 769 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 770 ipv4_is_zeronet(new_gw)) 771 goto reject_redirect; 772 773 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 774 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 775 goto reject_redirect; 776 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 777 goto reject_redirect; 778 } else { 779 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 780 goto reject_redirect; 781 } 782 783 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 784 if (!n) 785 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 786 if (!IS_ERR(n)) { 787 if (!(n->nud_state & NUD_VALID)) { 788 neigh_event_send(n, NULL); 789 } else { 790 if (fib_lookup(net, fl4, &res, 0) == 0) { 791 struct fib_nh_common *nhc = FIB_RES_NHC(res); 792 793 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 794 0, false, 795 jiffies + ip_rt_gc_timeout); 796 } 797 if (kill_route) 798 rt->dst.obsolete = DST_OBSOLETE_KILL; 799 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 800 } 801 neigh_release(n); 802 } 803 return; 804 805 reject_redirect: 806 #ifdef CONFIG_IP_ROUTE_VERBOSE 807 if (IN_DEV_LOG_MARTIANS(in_dev)) { 808 const struct iphdr *iph = (const struct iphdr *) skb->data; 809 __be32 daddr = iph->daddr; 810 __be32 saddr = iph->saddr; 811 812 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 813 " Advised path = %pI4 -> %pI4\n", 814 &old_gw, dev->name, &new_gw, 815 &saddr, &daddr); 816 } 817 #endif 818 ; 819 } 820 821 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 822 { 823 struct rtable *rt; 824 struct flowi4 fl4; 825 const struct iphdr *iph = (const struct iphdr *) skb->data; 826 struct net *net = dev_net(skb->dev); 827 int oif = skb->dev->ifindex; 828 u8 tos = RT_TOS(iph->tos); 829 u8 prot = iph->protocol; 830 u32 mark = skb->mark; 831 832 rt = (struct rtable *) dst; 833 834 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 835 __ip_do_redirect(rt, skb, &fl4, true); 836 } 837 838 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 839 { 840 struct rtable *rt = (struct rtable *)dst; 841 struct dst_entry *ret = dst; 842 843 if (rt) { 844 if (dst->obsolete > 0) { 845 ip_rt_put(rt); 846 ret = NULL; 847 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 848 rt->dst.expires) { 849 ip_rt_put(rt); 850 ret = NULL; 851 } 852 } 853 return ret; 854 } 855 856 /* 857 * Algorithm: 858 * 1. The first ip_rt_redirect_number redirects are sent 859 * with exponential backoff, then we stop sending them at all, 860 * assuming that the host ignores our redirects. 861 * 2. If we did not see packets requiring redirects 862 * during ip_rt_redirect_silence, we assume that the host 863 * forgot redirected route and start to send redirects again. 864 * 865 * This algorithm is much cheaper and more intelligent than dumb load limiting 866 * in icmp.c. 867 * 868 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 869 * and "frag. need" (breaks PMTU discovery) in icmp.c. 870 */ 871 872 void ip_rt_send_redirect(struct sk_buff *skb) 873 { 874 struct rtable *rt = skb_rtable(skb); 875 struct in_device *in_dev; 876 struct inet_peer *peer; 877 struct net *net; 878 int log_martians; 879 int vif; 880 881 rcu_read_lock(); 882 in_dev = __in_dev_get_rcu(rt->dst.dev); 883 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 884 rcu_read_unlock(); 885 return; 886 } 887 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 888 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 889 rcu_read_unlock(); 890 891 net = dev_net(rt->dst.dev); 892 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 893 if (!peer) { 894 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 895 rt_nexthop(rt, ip_hdr(skb)->daddr)); 896 return; 897 } 898 899 /* No redirected packets during ip_rt_redirect_silence; 900 * reset the algorithm. 901 */ 902 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 903 peer->rate_tokens = 0; 904 peer->n_redirects = 0; 905 } 906 907 /* Too many ignored redirects; do not send anything 908 * set dst.rate_last to the last seen redirected packet. 909 */ 910 if (peer->n_redirects >= ip_rt_redirect_number) { 911 peer->rate_last = jiffies; 912 goto out_put_peer; 913 } 914 915 /* Check for load limit; set rate_last to the latest sent 916 * redirect. 917 */ 918 if (peer->rate_tokens == 0 || 919 time_after(jiffies, 920 (peer->rate_last + 921 (ip_rt_redirect_load << peer->n_redirects)))) { 922 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 923 924 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 925 peer->rate_last = jiffies; 926 ++peer->n_redirects; 927 #ifdef CONFIG_IP_ROUTE_VERBOSE 928 if (log_martians && 929 peer->n_redirects == ip_rt_redirect_number) 930 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 931 &ip_hdr(skb)->saddr, inet_iif(skb), 932 &ip_hdr(skb)->daddr, &gw); 933 #endif 934 } 935 out_put_peer: 936 inet_putpeer(peer); 937 } 938 939 static int ip_error(struct sk_buff *skb) 940 { 941 struct rtable *rt = skb_rtable(skb); 942 struct net_device *dev = skb->dev; 943 struct in_device *in_dev; 944 struct inet_peer *peer; 945 unsigned long now; 946 struct net *net; 947 bool send; 948 int code; 949 950 if (netif_is_l3_master(skb->dev)) { 951 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 952 if (!dev) 953 goto out; 954 } 955 956 in_dev = __in_dev_get_rcu(dev); 957 958 /* IP on this device is disabled. */ 959 if (!in_dev) 960 goto out; 961 962 net = dev_net(rt->dst.dev); 963 if (!IN_DEV_FORWARD(in_dev)) { 964 switch (rt->dst.error) { 965 case EHOSTUNREACH: 966 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 967 break; 968 969 case ENETUNREACH: 970 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 971 break; 972 } 973 goto out; 974 } 975 976 switch (rt->dst.error) { 977 case EINVAL: 978 default: 979 goto out; 980 case EHOSTUNREACH: 981 code = ICMP_HOST_UNREACH; 982 break; 983 case ENETUNREACH: 984 code = ICMP_NET_UNREACH; 985 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 986 break; 987 case EACCES: 988 code = ICMP_PKT_FILTERED; 989 break; 990 } 991 992 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 993 l3mdev_master_ifindex(skb->dev), 1); 994 995 send = true; 996 if (peer) { 997 now = jiffies; 998 peer->rate_tokens += now - peer->rate_last; 999 if (peer->rate_tokens > ip_rt_error_burst) 1000 peer->rate_tokens = ip_rt_error_burst; 1001 peer->rate_last = now; 1002 if (peer->rate_tokens >= ip_rt_error_cost) 1003 peer->rate_tokens -= ip_rt_error_cost; 1004 else 1005 send = false; 1006 inet_putpeer(peer); 1007 } 1008 if (send) 1009 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1010 1011 out: kfree_skb(skb); 1012 return 0; 1013 } 1014 1015 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1016 { 1017 struct dst_entry *dst = &rt->dst; 1018 u32 old_mtu = ipv4_mtu(dst); 1019 struct fib_result res; 1020 bool lock = false; 1021 1022 if (ip_mtu_locked(dst)) 1023 return; 1024 1025 if (old_mtu < mtu) 1026 return; 1027 1028 if (mtu < ip_rt_min_pmtu) { 1029 lock = true; 1030 mtu = min(old_mtu, ip_rt_min_pmtu); 1031 } 1032 1033 if (rt->rt_pmtu == mtu && !lock && 1034 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1035 return; 1036 1037 rcu_read_lock(); 1038 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1039 struct fib_nh_common *nhc = FIB_RES_NHC(res); 1040 1041 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1042 jiffies + ip_rt_mtu_expires); 1043 } 1044 rcu_read_unlock(); 1045 } 1046 1047 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1048 struct sk_buff *skb, u32 mtu, 1049 bool confirm_neigh) 1050 { 1051 struct rtable *rt = (struct rtable *) dst; 1052 struct flowi4 fl4; 1053 1054 ip_rt_build_flow_key(&fl4, sk, skb); 1055 __ip_rt_update_pmtu(rt, &fl4, mtu); 1056 } 1057 1058 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1059 int oif, u8 protocol) 1060 { 1061 const struct iphdr *iph = (const struct iphdr *) skb->data; 1062 struct flowi4 fl4; 1063 struct rtable *rt; 1064 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1065 1066 __build_flow_key(net, &fl4, NULL, iph, oif, 1067 RT_TOS(iph->tos), protocol, mark, 0); 1068 rt = __ip_route_output_key(net, &fl4); 1069 if (!IS_ERR(rt)) { 1070 __ip_rt_update_pmtu(rt, &fl4, mtu); 1071 ip_rt_put(rt); 1072 } 1073 } 1074 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1075 1076 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1077 { 1078 const struct iphdr *iph = (const struct iphdr *) skb->data; 1079 struct flowi4 fl4; 1080 struct rtable *rt; 1081 1082 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1083 1084 if (!fl4.flowi4_mark) 1085 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1086 1087 rt = __ip_route_output_key(sock_net(sk), &fl4); 1088 if (!IS_ERR(rt)) { 1089 __ip_rt_update_pmtu(rt, &fl4, mtu); 1090 ip_rt_put(rt); 1091 } 1092 } 1093 1094 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1095 { 1096 const struct iphdr *iph = (const struct iphdr *) skb->data; 1097 struct flowi4 fl4; 1098 struct rtable *rt; 1099 struct dst_entry *odst = NULL; 1100 bool new = false; 1101 struct net *net = sock_net(sk); 1102 1103 bh_lock_sock(sk); 1104 1105 if (!ip_sk_accept_pmtu(sk)) 1106 goto out; 1107 1108 odst = sk_dst_get(sk); 1109 1110 if (sock_owned_by_user(sk) || !odst) { 1111 __ipv4_sk_update_pmtu(skb, sk, mtu); 1112 goto out; 1113 } 1114 1115 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1116 1117 rt = (struct rtable *)odst; 1118 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1119 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1120 if (IS_ERR(rt)) 1121 goto out; 1122 1123 new = true; 1124 } 1125 1126 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1127 1128 if (!dst_check(&rt->dst, 0)) { 1129 if (new) 1130 dst_release(&rt->dst); 1131 1132 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1133 if (IS_ERR(rt)) 1134 goto out; 1135 1136 new = true; 1137 } 1138 1139 if (new) 1140 sk_dst_set(sk, &rt->dst); 1141 1142 out: 1143 bh_unlock_sock(sk); 1144 dst_release(odst); 1145 } 1146 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1147 1148 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1149 int oif, u8 protocol) 1150 { 1151 const struct iphdr *iph = (const struct iphdr *) skb->data; 1152 struct flowi4 fl4; 1153 struct rtable *rt; 1154 1155 __build_flow_key(net, &fl4, NULL, iph, oif, 1156 RT_TOS(iph->tos), protocol, 0, 0); 1157 rt = __ip_route_output_key(net, &fl4); 1158 if (!IS_ERR(rt)) { 1159 __ip_do_redirect(rt, skb, &fl4, false); 1160 ip_rt_put(rt); 1161 } 1162 } 1163 EXPORT_SYMBOL_GPL(ipv4_redirect); 1164 1165 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1166 { 1167 const struct iphdr *iph = (const struct iphdr *) skb->data; 1168 struct flowi4 fl4; 1169 struct rtable *rt; 1170 struct net *net = sock_net(sk); 1171 1172 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1173 rt = __ip_route_output_key(net, &fl4); 1174 if (!IS_ERR(rt)) { 1175 __ip_do_redirect(rt, skb, &fl4, false); 1176 ip_rt_put(rt); 1177 } 1178 } 1179 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1180 1181 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1182 { 1183 struct rtable *rt = (struct rtable *) dst; 1184 1185 /* All IPV4 dsts are created with ->obsolete set to the value 1186 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1187 * into this function always. 1188 * 1189 * When a PMTU/redirect information update invalidates a route, 1190 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1191 * DST_OBSOLETE_DEAD. 1192 */ 1193 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1194 return NULL; 1195 return dst; 1196 } 1197 1198 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1199 { 1200 struct ip_options opt; 1201 int res; 1202 1203 /* Recompile ip options since IPCB may not be valid anymore. 1204 * Also check we have a reasonable ipv4 header. 1205 */ 1206 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1207 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1208 return; 1209 1210 memset(&opt, 0, sizeof(opt)); 1211 if (ip_hdr(skb)->ihl > 5) { 1212 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1213 return; 1214 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1215 1216 rcu_read_lock(); 1217 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1218 rcu_read_unlock(); 1219 1220 if (res) 1221 return; 1222 } 1223 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1224 } 1225 1226 static void ipv4_link_failure(struct sk_buff *skb) 1227 { 1228 struct rtable *rt; 1229 1230 ipv4_send_dest_unreach(skb); 1231 1232 rt = skb_rtable(skb); 1233 if (rt) 1234 dst_set_expires(&rt->dst, 0); 1235 } 1236 1237 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1238 { 1239 pr_debug("%s: %pI4 -> %pI4, %s\n", 1240 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1241 skb->dev ? skb->dev->name : "?"); 1242 kfree_skb(skb); 1243 WARN_ON(1); 1244 return 0; 1245 } 1246 1247 /* 1248 We do not cache source address of outgoing interface, 1249 because it is used only by IP RR, TS and SRR options, 1250 so that it out of fast path. 1251 1252 BTW remember: "addr" is allowed to be not aligned 1253 in IP options! 1254 */ 1255 1256 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1257 { 1258 __be32 src; 1259 1260 if (rt_is_output_route(rt)) 1261 src = ip_hdr(skb)->saddr; 1262 else { 1263 struct fib_result res; 1264 struct iphdr *iph = ip_hdr(skb); 1265 struct flowi4 fl4 = { 1266 .daddr = iph->daddr, 1267 .saddr = iph->saddr, 1268 .flowi4_tos = RT_TOS(iph->tos), 1269 .flowi4_oif = rt->dst.dev->ifindex, 1270 .flowi4_iif = skb->dev->ifindex, 1271 .flowi4_mark = skb->mark, 1272 }; 1273 1274 rcu_read_lock(); 1275 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1276 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1277 else 1278 src = inet_select_addr(rt->dst.dev, 1279 rt_nexthop(rt, iph->daddr), 1280 RT_SCOPE_UNIVERSE); 1281 rcu_read_unlock(); 1282 } 1283 memcpy(addr, &src, 4); 1284 } 1285 1286 #ifdef CONFIG_IP_ROUTE_CLASSID 1287 static void set_class_tag(struct rtable *rt, u32 tag) 1288 { 1289 if (!(rt->dst.tclassid & 0xFFFF)) 1290 rt->dst.tclassid |= tag & 0xFFFF; 1291 if (!(rt->dst.tclassid & 0xFFFF0000)) 1292 rt->dst.tclassid |= tag & 0xFFFF0000; 1293 } 1294 #endif 1295 1296 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1297 { 1298 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1299 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1300 ip_rt_min_advmss); 1301 1302 return min(advmss, IPV4_MAX_PMTU - header_size); 1303 } 1304 1305 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1306 { 1307 const struct rtable *rt = (const struct rtable *) dst; 1308 unsigned int mtu = rt->rt_pmtu; 1309 1310 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1311 mtu = dst_metric_raw(dst, RTAX_MTU); 1312 1313 if (mtu) 1314 return mtu; 1315 1316 mtu = READ_ONCE(dst->dev->mtu); 1317 1318 if (unlikely(ip_mtu_locked(dst))) { 1319 if (rt->rt_uses_gateway && mtu > 576) 1320 mtu = 576; 1321 } 1322 1323 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1324 1325 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1326 } 1327 1328 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1329 { 1330 struct fnhe_hash_bucket *hash; 1331 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1332 u32 hval = fnhe_hashfun(daddr); 1333 1334 spin_lock_bh(&fnhe_lock); 1335 1336 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1337 lockdep_is_held(&fnhe_lock)); 1338 hash += hval; 1339 1340 fnhe_p = &hash->chain; 1341 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1342 while (fnhe) { 1343 if (fnhe->fnhe_daddr == daddr) { 1344 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1345 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1346 /* set fnhe_daddr to 0 to ensure it won't bind with 1347 * new dsts in rt_bind_exception(). 1348 */ 1349 fnhe->fnhe_daddr = 0; 1350 fnhe_flush_routes(fnhe); 1351 kfree_rcu(fnhe, rcu); 1352 break; 1353 } 1354 fnhe_p = &fnhe->fnhe_next; 1355 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1356 lockdep_is_held(&fnhe_lock)); 1357 } 1358 1359 spin_unlock_bh(&fnhe_lock); 1360 } 1361 1362 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1363 __be32 daddr) 1364 { 1365 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1366 struct fib_nh_exception *fnhe; 1367 u32 hval; 1368 1369 if (!hash) 1370 return NULL; 1371 1372 hval = fnhe_hashfun(daddr); 1373 1374 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1375 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1376 if (fnhe->fnhe_daddr == daddr) { 1377 if (fnhe->fnhe_expires && 1378 time_after(jiffies, fnhe->fnhe_expires)) { 1379 ip_del_fnhe(nhc, daddr); 1380 break; 1381 } 1382 return fnhe; 1383 } 1384 } 1385 return NULL; 1386 } 1387 1388 /* MTU selection: 1389 * 1. mtu on route is locked - use it 1390 * 2. mtu from nexthop exception 1391 * 3. mtu from egress device 1392 */ 1393 1394 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1395 { 1396 struct fib_nh_common *nhc = res->nhc; 1397 struct net_device *dev = nhc->nhc_dev; 1398 struct fib_info *fi = res->fi; 1399 u32 mtu = 0; 1400 1401 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1402 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1403 mtu = fi->fib_mtu; 1404 1405 if (likely(!mtu)) { 1406 struct fib_nh_exception *fnhe; 1407 1408 fnhe = find_exception(nhc, daddr); 1409 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1410 mtu = fnhe->fnhe_pmtu; 1411 } 1412 1413 if (likely(!mtu)) 1414 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1415 1416 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1417 } 1418 1419 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1420 __be32 daddr, const bool do_cache) 1421 { 1422 bool ret = false; 1423 1424 spin_lock_bh(&fnhe_lock); 1425 1426 if (daddr == fnhe->fnhe_daddr) { 1427 struct rtable __rcu **porig; 1428 struct rtable *orig; 1429 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1430 1431 if (rt_is_input_route(rt)) 1432 porig = &fnhe->fnhe_rth_input; 1433 else 1434 porig = &fnhe->fnhe_rth_output; 1435 orig = rcu_dereference(*porig); 1436 1437 if (fnhe->fnhe_genid != genid) { 1438 fnhe->fnhe_genid = genid; 1439 fnhe->fnhe_gw = 0; 1440 fnhe->fnhe_pmtu = 0; 1441 fnhe->fnhe_expires = 0; 1442 fnhe->fnhe_mtu_locked = false; 1443 fnhe_flush_routes(fnhe); 1444 orig = NULL; 1445 } 1446 fill_route_from_fnhe(rt, fnhe); 1447 if (!rt->rt_gw4) { 1448 rt->rt_gw4 = daddr; 1449 rt->rt_gw_family = AF_INET; 1450 } 1451 1452 if (do_cache) { 1453 dst_hold(&rt->dst); 1454 rcu_assign_pointer(*porig, rt); 1455 if (orig) { 1456 dst_dev_put(&orig->dst); 1457 dst_release(&orig->dst); 1458 } 1459 ret = true; 1460 } 1461 1462 fnhe->fnhe_stamp = jiffies; 1463 } 1464 spin_unlock_bh(&fnhe_lock); 1465 1466 return ret; 1467 } 1468 1469 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1470 { 1471 struct rtable *orig, *prev, **p; 1472 bool ret = true; 1473 1474 if (rt_is_input_route(rt)) { 1475 p = (struct rtable **)&nhc->nhc_rth_input; 1476 } else { 1477 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1478 } 1479 orig = *p; 1480 1481 /* hold dst before doing cmpxchg() to avoid race condition 1482 * on this dst 1483 */ 1484 dst_hold(&rt->dst); 1485 prev = cmpxchg(p, orig, rt); 1486 if (prev == orig) { 1487 if (orig) { 1488 rt_add_uncached_list(orig); 1489 dst_release(&orig->dst); 1490 } 1491 } else { 1492 dst_release(&rt->dst); 1493 ret = false; 1494 } 1495 1496 return ret; 1497 } 1498 1499 struct uncached_list { 1500 spinlock_t lock; 1501 struct list_head head; 1502 }; 1503 1504 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1505 1506 void rt_add_uncached_list(struct rtable *rt) 1507 { 1508 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1509 1510 rt->rt_uncached_list = ul; 1511 1512 spin_lock_bh(&ul->lock); 1513 list_add_tail(&rt->rt_uncached, &ul->head); 1514 spin_unlock_bh(&ul->lock); 1515 } 1516 1517 void rt_del_uncached_list(struct rtable *rt) 1518 { 1519 if (!list_empty(&rt->rt_uncached)) { 1520 struct uncached_list *ul = rt->rt_uncached_list; 1521 1522 spin_lock_bh(&ul->lock); 1523 list_del(&rt->rt_uncached); 1524 spin_unlock_bh(&ul->lock); 1525 } 1526 } 1527 1528 static void ipv4_dst_destroy(struct dst_entry *dst) 1529 { 1530 struct rtable *rt = (struct rtable *)dst; 1531 1532 ip_dst_metrics_put(dst); 1533 rt_del_uncached_list(rt); 1534 } 1535 1536 void rt_flush_dev(struct net_device *dev) 1537 { 1538 struct rtable *rt; 1539 int cpu; 1540 1541 for_each_possible_cpu(cpu) { 1542 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1543 1544 spin_lock_bh(&ul->lock); 1545 list_for_each_entry(rt, &ul->head, rt_uncached) { 1546 if (rt->dst.dev != dev) 1547 continue; 1548 rt->dst.dev = blackhole_netdev; 1549 dev_hold(rt->dst.dev); 1550 dev_put(dev); 1551 } 1552 spin_unlock_bh(&ul->lock); 1553 } 1554 } 1555 1556 static bool rt_cache_valid(const struct rtable *rt) 1557 { 1558 return rt && 1559 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1560 !rt_is_expired(rt); 1561 } 1562 1563 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1564 const struct fib_result *res, 1565 struct fib_nh_exception *fnhe, 1566 struct fib_info *fi, u16 type, u32 itag, 1567 const bool do_cache) 1568 { 1569 bool cached = false; 1570 1571 if (fi) { 1572 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1573 1574 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1575 rt->rt_uses_gateway = 1; 1576 rt->rt_gw_family = nhc->nhc_gw_family; 1577 /* only INET and INET6 are supported */ 1578 if (likely(nhc->nhc_gw_family == AF_INET)) 1579 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1580 else 1581 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1582 } 1583 1584 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1585 1586 #ifdef CONFIG_IP_ROUTE_CLASSID 1587 if (nhc->nhc_family == AF_INET) { 1588 struct fib_nh *nh; 1589 1590 nh = container_of(nhc, struct fib_nh, nh_common); 1591 rt->dst.tclassid = nh->nh_tclassid; 1592 } 1593 #endif 1594 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1595 if (unlikely(fnhe)) 1596 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1597 else if (do_cache) 1598 cached = rt_cache_route(nhc, rt); 1599 if (unlikely(!cached)) { 1600 /* Routes we intend to cache in nexthop exception or 1601 * FIB nexthop have the DST_NOCACHE bit clear. 1602 * However, if we are unsuccessful at storing this 1603 * route into the cache we really need to set it. 1604 */ 1605 if (!rt->rt_gw4) { 1606 rt->rt_gw_family = AF_INET; 1607 rt->rt_gw4 = daddr; 1608 } 1609 rt_add_uncached_list(rt); 1610 } 1611 } else 1612 rt_add_uncached_list(rt); 1613 1614 #ifdef CONFIG_IP_ROUTE_CLASSID 1615 #ifdef CONFIG_IP_MULTIPLE_TABLES 1616 set_class_tag(rt, res->tclassid); 1617 #endif 1618 set_class_tag(rt, itag); 1619 #endif 1620 } 1621 1622 struct rtable *rt_dst_alloc(struct net_device *dev, 1623 unsigned int flags, u16 type, 1624 bool nopolicy, bool noxfrm, bool will_cache) 1625 { 1626 struct rtable *rt; 1627 1628 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1629 (will_cache ? 0 : DST_HOST) | 1630 (nopolicy ? DST_NOPOLICY : 0) | 1631 (noxfrm ? DST_NOXFRM : 0)); 1632 1633 if (rt) { 1634 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1635 rt->rt_flags = flags; 1636 rt->rt_type = type; 1637 rt->rt_is_input = 0; 1638 rt->rt_iif = 0; 1639 rt->rt_pmtu = 0; 1640 rt->rt_mtu_locked = 0; 1641 rt->rt_uses_gateway = 0; 1642 rt->rt_gw_family = 0; 1643 rt->rt_gw4 = 0; 1644 INIT_LIST_HEAD(&rt->rt_uncached); 1645 1646 rt->dst.output = ip_output; 1647 if (flags & RTCF_LOCAL) 1648 rt->dst.input = ip_local_deliver; 1649 } 1650 1651 return rt; 1652 } 1653 EXPORT_SYMBOL(rt_dst_alloc); 1654 1655 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1656 { 1657 struct rtable *new_rt; 1658 1659 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1660 rt->dst.flags); 1661 1662 if (new_rt) { 1663 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1664 new_rt->rt_flags = rt->rt_flags; 1665 new_rt->rt_type = rt->rt_type; 1666 new_rt->rt_is_input = rt->rt_is_input; 1667 new_rt->rt_iif = rt->rt_iif; 1668 new_rt->rt_pmtu = rt->rt_pmtu; 1669 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1670 new_rt->rt_gw_family = rt->rt_gw_family; 1671 if (rt->rt_gw_family == AF_INET) 1672 new_rt->rt_gw4 = rt->rt_gw4; 1673 else if (rt->rt_gw_family == AF_INET6) 1674 new_rt->rt_gw6 = rt->rt_gw6; 1675 INIT_LIST_HEAD(&new_rt->rt_uncached); 1676 1677 new_rt->dst.flags |= DST_HOST; 1678 new_rt->dst.input = rt->dst.input; 1679 new_rt->dst.output = rt->dst.output; 1680 new_rt->dst.error = rt->dst.error; 1681 new_rt->dst.lastuse = jiffies; 1682 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1683 } 1684 return new_rt; 1685 } 1686 EXPORT_SYMBOL(rt_dst_clone); 1687 1688 /* called in rcu_read_lock() section */ 1689 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1690 u8 tos, struct net_device *dev, 1691 struct in_device *in_dev, u32 *itag) 1692 { 1693 int err; 1694 1695 /* Primary sanity checks. */ 1696 if (!in_dev) 1697 return -EINVAL; 1698 1699 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1700 skb->protocol != htons(ETH_P_IP)) 1701 return -EINVAL; 1702 1703 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1704 return -EINVAL; 1705 1706 if (ipv4_is_zeronet(saddr)) { 1707 if (!ipv4_is_local_multicast(daddr) && 1708 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1709 return -EINVAL; 1710 } else { 1711 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1712 in_dev, itag); 1713 if (err < 0) 1714 return err; 1715 } 1716 return 0; 1717 } 1718 1719 /* called in rcu_read_lock() section */ 1720 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1721 u8 tos, struct net_device *dev, int our) 1722 { 1723 struct in_device *in_dev = __in_dev_get_rcu(dev); 1724 unsigned int flags = RTCF_MULTICAST; 1725 struct rtable *rth; 1726 u32 itag = 0; 1727 int err; 1728 1729 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1730 if (err) 1731 return err; 1732 1733 if (our) 1734 flags |= RTCF_LOCAL; 1735 1736 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1737 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1738 if (!rth) 1739 return -ENOBUFS; 1740 1741 #ifdef CONFIG_IP_ROUTE_CLASSID 1742 rth->dst.tclassid = itag; 1743 #endif 1744 rth->dst.output = ip_rt_bug; 1745 rth->rt_is_input= 1; 1746 1747 #ifdef CONFIG_IP_MROUTE 1748 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1749 rth->dst.input = ip_mr_input; 1750 #endif 1751 RT_CACHE_STAT_INC(in_slow_mc); 1752 1753 skb_dst_set(skb, &rth->dst); 1754 return 0; 1755 } 1756 1757 1758 static void ip_handle_martian_source(struct net_device *dev, 1759 struct in_device *in_dev, 1760 struct sk_buff *skb, 1761 __be32 daddr, 1762 __be32 saddr) 1763 { 1764 RT_CACHE_STAT_INC(in_martian_src); 1765 #ifdef CONFIG_IP_ROUTE_VERBOSE 1766 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1767 /* 1768 * RFC1812 recommendation, if source is martian, 1769 * the only hint is MAC header. 1770 */ 1771 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1772 &daddr, &saddr, dev->name); 1773 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1774 print_hex_dump(KERN_WARNING, "ll header: ", 1775 DUMP_PREFIX_OFFSET, 16, 1, 1776 skb_mac_header(skb), 1777 dev->hard_header_len, false); 1778 } 1779 } 1780 #endif 1781 } 1782 1783 /* called in rcu_read_lock() section */ 1784 static int __mkroute_input(struct sk_buff *skb, 1785 const struct fib_result *res, 1786 struct in_device *in_dev, 1787 __be32 daddr, __be32 saddr, u32 tos) 1788 { 1789 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1790 struct net_device *dev = nhc->nhc_dev; 1791 struct fib_nh_exception *fnhe; 1792 struct rtable *rth; 1793 int err; 1794 struct in_device *out_dev; 1795 bool do_cache; 1796 u32 itag = 0; 1797 1798 /* get a working reference to the output device */ 1799 out_dev = __in_dev_get_rcu(dev); 1800 if (!out_dev) { 1801 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1802 return -EINVAL; 1803 } 1804 1805 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1806 in_dev->dev, in_dev, &itag); 1807 if (err < 0) { 1808 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1809 saddr); 1810 1811 goto cleanup; 1812 } 1813 1814 do_cache = res->fi && !itag; 1815 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1816 skb->protocol == htons(ETH_P_IP)) { 1817 __be32 gw; 1818 1819 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1820 if (IN_DEV_SHARED_MEDIA(out_dev) || 1821 inet_addr_onlink(out_dev, saddr, gw)) 1822 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1823 } 1824 1825 if (skb->protocol != htons(ETH_P_IP)) { 1826 /* Not IP (i.e. ARP). Do not create route, if it is 1827 * invalid for proxy arp. DNAT routes are always valid. 1828 * 1829 * Proxy arp feature have been extended to allow, ARP 1830 * replies back to the same interface, to support 1831 * Private VLAN switch technologies. See arp.c. 1832 */ 1833 if (out_dev == in_dev && 1834 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1835 err = -EINVAL; 1836 goto cleanup; 1837 } 1838 } 1839 1840 fnhe = find_exception(nhc, daddr); 1841 if (do_cache) { 1842 if (fnhe) 1843 rth = rcu_dereference(fnhe->fnhe_rth_input); 1844 else 1845 rth = rcu_dereference(nhc->nhc_rth_input); 1846 if (rt_cache_valid(rth)) { 1847 skb_dst_set_noref(skb, &rth->dst); 1848 goto out; 1849 } 1850 } 1851 1852 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1853 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1854 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1855 if (!rth) { 1856 err = -ENOBUFS; 1857 goto cleanup; 1858 } 1859 1860 rth->rt_is_input = 1; 1861 RT_CACHE_STAT_INC(in_slow_tot); 1862 1863 rth->dst.input = ip_forward; 1864 1865 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1866 do_cache); 1867 lwtunnel_set_redirect(&rth->dst); 1868 skb_dst_set(skb, &rth->dst); 1869 out: 1870 err = 0; 1871 cleanup: 1872 return err; 1873 } 1874 1875 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1876 /* To make ICMP packets follow the right flow, the multipath hash is 1877 * calculated from the inner IP addresses. 1878 */ 1879 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1880 struct flow_keys *hash_keys) 1881 { 1882 const struct iphdr *outer_iph = ip_hdr(skb); 1883 const struct iphdr *key_iph = outer_iph; 1884 const struct iphdr *inner_iph; 1885 const struct icmphdr *icmph; 1886 struct iphdr _inner_iph; 1887 struct icmphdr _icmph; 1888 1889 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1890 goto out; 1891 1892 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1893 goto out; 1894 1895 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1896 &_icmph); 1897 if (!icmph) 1898 goto out; 1899 1900 if (!icmp_is_err(icmph->type)) 1901 goto out; 1902 1903 inner_iph = skb_header_pointer(skb, 1904 outer_iph->ihl * 4 + sizeof(_icmph), 1905 sizeof(_inner_iph), &_inner_iph); 1906 if (!inner_iph) 1907 goto out; 1908 1909 key_iph = inner_iph; 1910 out: 1911 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1912 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1913 } 1914 1915 /* if skb is set it will be used and fl4 can be NULL */ 1916 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1917 const struct sk_buff *skb, struct flow_keys *flkeys) 1918 { 1919 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1920 struct flow_keys hash_keys; 1921 u32 mhash; 1922 1923 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1924 case 0: 1925 memset(&hash_keys, 0, sizeof(hash_keys)); 1926 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1927 if (skb) { 1928 ip_multipath_l3_keys(skb, &hash_keys); 1929 } else { 1930 hash_keys.addrs.v4addrs.src = fl4->saddr; 1931 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1932 } 1933 break; 1934 case 1: 1935 /* skb is currently provided only when forwarding */ 1936 if (skb) { 1937 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1938 struct flow_keys keys; 1939 1940 /* short-circuit if we already have L4 hash present */ 1941 if (skb->l4_hash) 1942 return skb_get_hash_raw(skb) >> 1; 1943 1944 memset(&hash_keys, 0, sizeof(hash_keys)); 1945 1946 if (!flkeys) { 1947 skb_flow_dissect_flow_keys(skb, &keys, flag); 1948 flkeys = &keys; 1949 } 1950 1951 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1952 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1953 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1954 hash_keys.ports.src = flkeys->ports.src; 1955 hash_keys.ports.dst = flkeys->ports.dst; 1956 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1957 } else { 1958 memset(&hash_keys, 0, sizeof(hash_keys)); 1959 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1960 hash_keys.addrs.v4addrs.src = fl4->saddr; 1961 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1962 hash_keys.ports.src = fl4->fl4_sport; 1963 hash_keys.ports.dst = fl4->fl4_dport; 1964 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1965 } 1966 break; 1967 case 2: 1968 memset(&hash_keys, 0, sizeof(hash_keys)); 1969 /* skb is currently provided only when forwarding */ 1970 if (skb) { 1971 struct flow_keys keys; 1972 1973 skb_flow_dissect_flow_keys(skb, &keys, 0); 1974 /* Inner can be v4 or v6 */ 1975 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1976 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1977 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1981 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1982 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1983 hash_keys.tags.flow_label = keys.tags.flow_label; 1984 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1985 } else { 1986 /* Same as case 0 */ 1987 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1988 ip_multipath_l3_keys(skb, &hash_keys); 1989 } 1990 } else { 1991 /* Same as case 0 */ 1992 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1993 hash_keys.addrs.v4addrs.src = fl4->saddr; 1994 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1995 } 1996 break; 1997 } 1998 mhash = flow_hash_from_keys(&hash_keys); 1999 2000 if (multipath_hash) 2001 mhash = jhash_2words(mhash, multipath_hash, 0); 2002 2003 return mhash >> 1; 2004 } 2005 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2006 2007 static int ip_mkroute_input(struct sk_buff *skb, 2008 struct fib_result *res, 2009 struct in_device *in_dev, 2010 __be32 daddr, __be32 saddr, u32 tos, 2011 struct flow_keys *hkeys) 2012 { 2013 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2014 if (res->fi && fib_info_num_path(res->fi) > 1) { 2015 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2016 2017 fib_select_multipath(res, h); 2018 } 2019 #endif 2020 2021 /* create a routing cache entry */ 2022 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2023 } 2024 2025 /* Implements all the saddr-related checks as ip_route_input_slow(), 2026 * assuming daddr is valid and the destination is not a local broadcast one. 2027 * Uses the provided hint instead of performing a route lookup. 2028 */ 2029 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2030 u8 tos, struct net_device *dev, 2031 const struct sk_buff *hint) 2032 { 2033 struct in_device *in_dev = __in_dev_get_rcu(dev); 2034 struct rtable *rt = (struct rtable *)hint; 2035 struct net *net = dev_net(dev); 2036 int err = -EINVAL; 2037 u32 tag = 0; 2038 2039 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2040 goto martian_source; 2041 2042 if (ipv4_is_zeronet(saddr)) 2043 goto martian_source; 2044 2045 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2046 goto martian_source; 2047 2048 if (rt->rt_type != RTN_LOCAL) 2049 goto skip_validate_source; 2050 2051 tos &= IPTOS_RT_MASK; 2052 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag); 2053 if (err < 0) 2054 goto martian_source; 2055 2056 skip_validate_source: 2057 skb_dst_copy(skb, hint); 2058 return 0; 2059 2060 martian_source: 2061 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2062 return err; 2063 } 2064 2065 /* 2066 * NOTE. We drop all the packets that has local source 2067 * addresses, because every properly looped back packet 2068 * must have correct destination already attached by output routine. 2069 * Changes in the enforced policies must be applied also to 2070 * ip_route_use_hint(). 2071 * 2072 * Such approach solves two big problems: 2073 * 1. Not simplex devices are handled properly. 2074 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2075 * called with rcu_read_lock() 2076 */ 2077 2078 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2079 u8 tos, struct net_device *dev, 2080 struct fib_result *res) 2081 { 2082 struct in_device *in_dev = __in_dev_get_rcu(dev); 2083 struct flow_keys *flkeys = NULL, _flkeys; 2084 struct net *net = dev_net(dev); 2085 struct ip_tunnel_info *tun_info; 2086 int err = -EINVAL; 2087 unsigned int flags = 0; 2088 u32 itag = 0; 2089 struct rtable *rth; 2090 struct flowi4 fl4; 2091 bool do_cache = true; 2092 2093 /* IP on this device is disabled. */ 2094 2095 if (!in_dev) 2096 goto out; 2097 2098 /* Check for the most weird martians, which can be not detected 2099 by fib_lookup. 2100 */ 2101 2102 tun_info = skb_tunnel_info(skb); 2103 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2104 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2105 else 2106 fl4.flowi4_tun_key.tun_id = 0; 2107 skb_dst_drop(skb); 2108 2109 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2110 goto martian_source; 2111 2112 res->fi = NULL; 2113 res->table = NULL; 2114 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2115 goto brd_input; 2116 2117 /* Accept zero addresses only to limited broadcast; 2118 * I even do not know to fix it or not. Waiting for complains :-) 2119 */ 2120 if (ipv4_is_zeronet(saddr)) 2121 goto martian_source; 2122 2123 if (ipv4_is_zeronet(daddr)) 2124 goto martian_destination; 2125 2126 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2127 * and call it once if daddr or/and saddr are loopback addresses 2128 */ 2129 if (ipv4_is_loopback(daddr)) { 2130 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2131 goto martian_destination; 2132 } else if (ipv4_is_loopback(saddr)) { 2133 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2134 goto martian_source; 2135 } 2136 2137 /* 2138 * Now we are ready to route packet. 2139 */ 2140 fl4.flowi4_oif = 0; 2141 fl4.flowi4_iif = dev->ifindex; 2142 fl4.flowi4_mark = skb->mark; 2143 fl4.flowi4_tos = tos; 2144 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2145 fl4.flowi4_flags = 0; 2146 fl4.daddr = daddr; 2147 fl4.saddr = saddr; 2148 fl4.flowi4_uid = sock_net_uid(net, NULL); 2149 2150 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2151 flkeys = &_flkeys; 2152 } else { 2153 fl4.flowi4_proto = 0; 2154 fl4.fl4_sport = 0; 2155 fl4.fl4_dport = 0; 2156 } 2157 2158 err = fib_lookup(net, &fl4, res, 0); 2159 if (err != 0) { 2160 if (!IN_DEV_FORWARD(in_dev)) 2161 err = -EHOSTUNREACH; 2162 goto no_route; 2163 } 2164 2165 if (res->type == RTN_BROADCAST) { 2166 if (IN_DEV_BFORWARD(in_dev)) 2167 goto make_route; 2168 /* not do cache if bc_forwarding is enabled */ 2169 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2170 do_cache = false; 2171 goto brd_input; 2172 } 2173 2174 if (res->type == RTN_LOCAL) { 2175 err = fib_validate_source(skb, saddr, daddr, tos, 2176 0, dev, in_dev, &itag); 2177 if (err < 0) 2178 goto martian_source; 2179 goto local_input; 2180 } 2181 2182 if (!IN_DEV_FORWARD(in_dev)) { 2183 err = -EHOSTUNREACH; 2184 goto no_route; 2185 } 2186 if (res->type != RTN_UNICAST) 2187 goto martian_destination; 2188 2189 make_route: 2190 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2191 out: return err; 2192 2193 brd_input: 2194 if (skb->protocol != htons(ETH_P_IP)) 2195 goto e_inval; 2196 2197 if (!ipv4_is_zeronet(saddr)) { 2198 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2199 in_dev, &itag); 2200 if (err < 0) 2201 goto martian_source; 2202 } 2203 flags |= RTCF_BROADCAST; 2204 res->type = RTN_BROADCAST; 2205 RT_CACHE_STAT_INC(in_brd); 2206 2207 local_input: 2208 do_cache &= res->fi && !itag; 2209 if (do_cache) { 2210 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2211 2212 rth = rcu_dereference(nhc->nhc_rth_input); 2213 if (rt_cache_valid(rth)) { 2214 skb_dst_set_noref(skb, &rth->dst); 2215 err = 0; 2216 goto out; 2217 } 2218 } 2219 2220 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2221 flags | RTCF_LOCAL, res->type, 2222 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2223 if (!rth) 2224 goto e_nobufs; 2225 2226 rth->dst.output= ip_rt_bug; 2227 #ifdef CONFIG_IP_ROUTE_CLASSID 2228 rth->dst.tclassid = itag; 2229 #endif 2230 rth->rt_is_input = 1; 2231 2232 RT_CACHE_STAT_INC(in_slow_tot); 2233 if (res->type == RTN_UNREACHABLE) { 2234 rth->dst.input= ip_error; 2235 rth->dst.error= -err; 2236 rth->rt_flags &= ~RTCF_LOCAL; 2237 } 2238 2239 if (do_cache) { 2240 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2241 2242 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2243 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2244 WARN_ON(rth->dst.input == lwtunnel_input); 2245 rth->dst.lwtstate->orig_input = rth->dst.input; 2246 rth->dst.input = lwtunnel_input; 2247 } 2248 2249 if (unlikely(!rt_cache_route(nhc, rth))) 2250 rt_add_uncached_list(rth); 2251 } 2252 skb_dst_set(skb, &rth->dst); 2253 err = 0; 2254 goto out; 2255 2256 no_route: 2257 RT_CACHE_STAT_INC(in_no_route); 2258 res->type = RTN_UNREACHABLE; 2259 res->fi = NULL; 2260 res->table = NULL; 2261 goto local_input; 2262 2263 /* 2264 * Do not cache martian addresses: they should be logged (RFC1812) 2265 */ 2266 martian_destination: 2267 RT_CACHE_STAT_INC(in_martian_dst); 2268 #ifdef CONFIG_IP_ROUTE_VERBOSE 2269 if (IN_DEV_LOG_MARTIANS(in_dev)) 2270 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2271 &daddr, &saddr, dev->name); 2272 #endif 2273 2274 e_inval: 2275 err = -EINVAL; 2276 goto out; 2277 2278 e_nobufs: 2279 err = -ENOBUFS; 2280 goto out; 2281 2282 martian_source: 2283 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2284 goto out; 2285 } 2286 2287 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2288 u8 tos, struct net_device *dev) 2289 { 2290 struct fib_result res; 2291 int err; 2292 2293 tos &= IPTOS_RT_MASK; 2294 rcu_read_lock(); 2295 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2296 rcu_read_unlock(); 2297 2298 return err; 2299 } 2300 EXPORT_SYMBOL(ip_route_input_noref); 2301 2302 /* called with rcu_read_lock held */ 2303 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2304 u8 tos, struct net_device *dev, struct fib_result *res) 2305 { 2306 /* Multicast recognition logic is moved from route cache to here. 2307 The problem was that too many Ethernet cards have broken/missing 2308 hardware multicast filters :-( As result the host on multicasting 2309 network acquires a lot of useless route cache entries, sort of 2310 SDR messages from all the world. Now we try to get rid of them. 2311 Really, provided software IP multicast filter is organized 2312 reasonably (at least, hashed), it does not result in a slowdown 2313 comparing with route cache reject entries. 2314 Note, that multicast routers are not affected, because 2315 route cache entry is created eventually. 2316 */ 2317 if (ipv4_is_multicast(daddr)) { 2318 struct in_device *in_dev = __in_dev_get_rcu(dev); 2319 int our = 0; 2320 int err = -EINVAL; 2321 2322 if (!in_dev) 2323 return err; 2324 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2325 ip_hdr(skb)->protocol); 2326 2327 /* check l3 master if no match yet */ 2328 if (!our && netif_is_l3_slave(dev)) { 2329 struct in_device *l3_in_dev; 2330 2331 l3_in_dev = __in_dev_get_rcu(skb->dev); 2332 if (l3_in_dev) 2333 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2334 ip_hdr(skb)->protocol); 2335 } 2336 2337 if (our 2338 #ifdef CONFIG_IP_MROUTE 2339 || 2340 (!ipv4_is_local_multicast(daddr) && 2341 IN_DEV_MFORWARD(in_dev)) 2342 #endif 2343 ) { 2344 err = ip_route_input_mc(skb, daddr, saddr, 2345 tos, dev, our); 2346 } 2347 return err; 2348 } 2349 2350 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2351 } 2352 2353 /* called with rcu_read_lock() */ 2354 static struct rtable *__mkroute_output(const struct fib_result *res, 2355 const struct flowi4 *fl4, int orig_oif, 2356 struct net_device *dev_out, 2357 unsigned int flags) 2358 { 2359 struct fib_info *fi = res->fi; 2360 struct fib_nh_exception *fnhe; 2361 struct in_device *in_dev; 2362 u16 type = res->type; 2363 struct rtable *rth; 2364 bool do_cache; 2365 2366 in_dev = __in_dev_get_rcu(dev_out); 2367 if (!in_dev) 2368 return ERR_PTR(-EINVAL); 2369 2370 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2371 if (ipv4_is_loopback(fl4->saddr) && 2372 !(dev_out->flags & IFF_LOOPBACK) && 2373 !netif_is_l3_master(dev_out)) 2374 return ERR_PTR(-EINVAL); 2375 2376 if (ipv4_is_lbcast(fl4->daddr)) 2377 type = RTN_BROADCAST; 2378 else if (ipv4_is_multicast(fl4->daddr)) 2379 type = RTN_MULTICAST; 2380 else if (ipv4_is_zeronet(fl4->daddr)) 2381 return ERR_PTR(-EINVAL); 2382 2383 if (dev_out->flags & IFF_LOOPBACK) 2384 flags |= RTCF_LOCAL; 2385 2386 do_cache = true; 2387 if (type == RTN_BROADCAST) { 2388 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2389 fi = NULL; 2390 } else if (type == RTN_MULTICAST) { 2391 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2392 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2393 fl4->flowi4_proto)) 2394 flags &= ~RTCF_LOCAL; 2395 else 2396 do_cache = false; 2397 /* If multicast route do not exist use 2398 * default one, but do not gateway in this case. 2399 * Yes, it is hack. 2400 */ 2401 if (fi && res->prefixlen < 4) 2402 fi = NULL; 2403 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2404 (orig_oif != dev_out->ifindex)) { 2405 /* For local routes that require a particular output interface 2406 * we do not want to cache the result. Caching the result 2407 * causes incorrect behaviour when there are multiple source 2408 * addresses on the interface, the end result being that if the 2409 * intended recipient is waiting on that interface for the 2410 * packet he won't receive it because it will be delivered on 2411 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2412 * be set to the loopback interface as well. 2413 */ 2414 do_cache = false; 2415 } 2416 2417 fnhe = NULL; 2418 do_cache &= fi != NULL; 2419 if (fi) { 2420 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2421 struct rtable __rcu **prth; 2422 2423 fnhe = find_exception(nhc, fl4->daddr); 2424 if (!do_cache) 2425 goto add; 2426 if (fnhe) { 2427 prth = &fnhe->fnhe_rth_output; 2428 } else { 2429 if (unlikely(fl4->flowi4_flags & 2430 FLOWI_FLAG_KNOWN_NH && 2431 !(nhc->nhc_gw_family && 2432 nhc->nhc_scope == RT_SCOPE_LINK))) { 2433 do_cache = false; 2434 goto add; 2435 } 2436 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2437 } 2438 rth = rcu_dereference(*prth); 2439 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2440 return rth; 2441 } 2442 2443 add: 2444 rth = rt_dst_alloc(dev_out, flags, type, 2445 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2446 IN_DEV_CONF_GET(in_dev, NOXFRM), 2447 do_cache); 2448 if (!rth) 2449 return ERR_PTR(-ENOBUFS); 2450 2451 rth->rt_iif = orig_oif; 2452 2453 RT_CACHE_STAT_INC(out_slow_tot); 2454 2455 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2456 if (flags & RTCF_LOCAL && 2457 !(dev_out->flags & IFF_LOOPBACK)) { 2458 rth->dst.output = ip_mc_output; 2459 RT_CACHE_STAT_INC(out_slow_mc); 2460 } 2461 #ifdef CONFIG_IP_MROUTE 2462 if (type == RTN_MULTICAST) { 2463 if (IN_DEV_MFORWARD(in_dev) && 2464 !ipv4_is_local_multicast(fl4->daddr)) { 2465 rth->dst.input = ip_mr_input; 2466 rth->dst.output = ip_mc_output; 2467 } 2468 } 2469 #endif 2470 } 2471 2472 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2473 lwtunnel_set_redirect(&rth->dst); 2474 2475 return rth; 2476 } 2477 2478 /* 2479 * Major route resolver routine. 2480 */ 2481 2482 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2483 const struct sk_buff *skb) 2484 { 2485 __u8 tos = RT_FL_TOS(fl4); 2486 struct fib_result res = { 2487 .type = RTN_UNSPEC, 2488 .fi = NULL, 2489 .table = NULL, 2490 .tclassid = 0, 2491 }; 2492 struct rtable *rth; 2493 2494 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2495 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2496 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2497 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2498 2499 rcu_read_lock(); 2500 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2501 rcu_read_unlock(); 2502 2503 return rth; 2504 } 2505 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2506 2507 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2508 struct fib_result *res, 2509 const struct sk_buff *skb) 2510 { 2511 struct net_device *dev_out = NULL; 2512 int orig_oif = fl4->flowi4_oif; 2513 unsigned int flags = 0; 2514 struct rtable *rth; 2515 int err; 2516 2517 if (fl4->saddr) { 2518 if (ipv4_is_multicast(fl4->saddr) || 2519 ipv4_is_lbcast(fl4->saddr) || 2520 ipv4_is_zeronet(fl4->saddr)) { 2521 rth = ERR_PTR(-EINVAL); 2522 goto out; 2523 } 2524 2525 rth = ERR_PTR(-ENETUNREACH); 2526 2527 /* I removed check for oif == dev_out->oif here. 2528 It was wrong for two reasons: 2529 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2530 is assigned to multiple interfaces. 2531 2. Moreover, we are allowed to send packets with saddr 2532 of another iface. --ANK 2533 */ 2534 2535 if (fl4->flowi4_oif == 0 && 2536 (ipv4_is_multicast(fl4->daddr) || 2537 ipv4_is_lbcast(fl4->daddr))) { 2538 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2539 dev_out = __ip_dev_find(net, fl4->saddr, false); 2540 if (!dev_out) 2541 goto out; 2542 2543 /* Special hack: user can direct multicasts 2544 and limited broadcast via necessary interface 2545 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2546 This hack is not just for fun, it allows 2547 vic,vat and friends to work. 2548 They bind socket to loopback, set ttl to zero 2549 and expect that it will work. 2550 From the viewpoint of routing cache they are broken, 2551 because we are not allowed to build multicast path 2552 with loopback source addr (look, routing cache 2553 cannot know, that ttl is zero, so that packet 2554 will not leave this host and route is valid). 2555 Luckily, this hack is good workaround. 2556 */ 2557 2558 fl4->flowi4_oif = dev_out->ifindex; 2559 goto make_route; 2560 } 2561 2562 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2563 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2564 if (!__ip_dev_find(net, fl4->saddr, false)) 2565 goto out; 2566 } 2567 } 2568 2569 2570 if (fl4->flowi4_oif) { 2571 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2572 rth = ERR_PTR(-ENODEV); 2573 if (!dev_out) 2574 goto out; 2575 2576 /* RACE: Check return value of inet_select_addr instead. */ 2577 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2578 rth = ERR_PTR(-ENETUNREACH); 2579 goto out; 2580 } 2581 if (ipv4_is_local_multicast(fl4->daddr) || 2582 ipv4_is_lbcast(fl4->daddr) || 2583 fl4->flowi4_proto == IPPROTO_IGMP) { 2584 if (!fl4->saddr) 2585 fl4->saddr = inet_select_addr(dev_out, 0, 2586 RT_SCOPE_LINK); 2587 goto make_route; 2588 } 2589 if (!fl4->saddr) { 2590 if (ipv4_is_multicast(fl4->daddr)) 2591 fl4->saddr = inet_select_addr(dev_out, 0, 2592 fl4->flowi4_scope); 2593 else if (!fl4->daddr) 2594 fl4->saddr = inet_select_addr(dev_out, 0, 2595 RT_SCOPE_HOST); 2596 } 2597 } 2598 2599 if (!fl4->daddr) { 2600 fl4->daddr = fl4->saddr; 2601 if (!fl4->daddr) 2602 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2603 dev_out = net->loopback_dev; 2604 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2605 res->type = RTN_LOCAL; 2606 flags |= RTCF_LOCAL; 2607 goto make_route; 2608 } 2609 2610 err = fib_lookup(net, fl4, res, 0); 2611 if (err) { 2612 res->fi = NULL; 2613 res->table = NULL; 2614 if (fl4->flowi4_oif && 2615 (ipv4_is_multicast(fl4->daddr) || 2616 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2617 /* Apparently, routing tables are wrong. Assume, 2618 that the destination is on link. 2619 2620 WHY? DW. 2621 Because we are allowed to send to iface 2622 even if it has NO routes and NO assigned 2623 addresses. When oif is specified, routing 2624 tables are looked up with only one purpose: 2625 to catch if destination is gatewayed, rather than 2626 direct. Moreover, if MSG_DONTROUTE is set, 2627 we send packet, ignoring both routing tables 2628 and ifaddr state. --ANK 2629 2630 2631 We could make it even if oif is unknown, 2632 likely IPv6, but we do not. 2633 */ 2634 2635 if (fl4->saddr == 0) 2636 fl4->saddr = inet_select_addr(dev_out, 0, 2637 RT_SCOPE_LINK); 2638 res->type = RTN_UNICAST; 2639 goto make_route; 2640 } 2641 rth = ERR_PTR(err); 2642 goto out; 2643 } 2644 2645 if (res->type == RTN_LOCAL) { 2646 if (!fl4->saddr) { 2647 if (res->fi->fib_prefsrc) 2648 fl4->saddr = res->fi->fib_prefsrc; 2649 else 2650 fl4->saddr = fl4->daddr; 2651 } 2652 2653 /* L3 master device is the loopback for that domain */ 2654 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2655 net->loopback_dev; 2656 2657 /* make sure orig_oif points to fib result device even 2658 * though packet rx/tx happens over loopback or l3mdev 2659 */ 2660 orig_oif = FIB_RES_OIF(*res); 2661 2662 fl4->flowi4_oif = dev_out->ifindex; 2663 flags |= RTCF_LOCAL; 2664 goto make_route; 2665 } 2666 2667 fib_select_path(net, res, fl4, skb); 2668 2669 dev_out = FIB_RES_DEV(*res); 2670 fl4->flowi4_oif = dev_out->ifindex; 2671 2672 2673 make_route: 2674 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2675 2676 out: 2677 return rth; 2678 } 2679 2680 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2681 { 2682 return NULL; 2683 } 2684 2685 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2686 { 2687 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2688 2689 return mtu ? : dst->dev->mtu; 2690 } 2691 2692 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2693 struct sk_buff *skb, u32 mtu, 2694 bool confirm_neigh) 2695 { 2696 } 2697 2698 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2699 struct sk_buff *skb) 2700 { 2701 } 2702 2703 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2704 unsigned long old) 2705 { 2706 return NULL; 2707 } 2708 2709 static struct dst_ops ipv4_dst_blackhole_ops = { 2710 .family = AF_INET, 2711 .check = ipv4_blackhole_dst_check, 2712 .mtu = ipv4_blackhole_mtu, 2713 .default_advmss = ipv4_default_advmss, 2714 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2715 .redirect = ipv4_rt_blackhole_redirect, 2716 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2717 .neigh_lookup = ipv4_neigh_lookup, 2718 }; 2719 2720 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2721 { 2722 struct rtable *ort = (struct rtable *) dst_orig; 2723 struct rtable *rt; 2724 2725 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2726 if (rt) { 2727 struct dst_entry *new = &rt->dst; 2728 2729 new->__use = 1; 2730 new->input = dst_discard; 2731 new->output = dst_discard_out; 2732 2733 new->dev = net->loopback_dev; 2734 if (new->dev) 2735 dev_hold(new->dev); 2736 2737 rt->rt_is_input = ort->rt_is_input; 2738 rt->rt_iif = ort->rt_iif; 2739 rt->rt_pmtu = ort->rt_pmtu; 2740 rt->rt_mtu_locked = ort->rt_mtu_locked; 2741 2742 rt->rt_genid = rt_genid_ipv4(net); 2743 rt->rt_flags = ort->rt_flags; 2744 rt->rt_type = ort->rt_type; 2745 rt->rt_uses_gateway = ort->rt_uses_gateway; 2746 rt->rt_gw_family = ort->rt_gw_family; 2747 if (rt->rt_gw_family == AF_INET) 2748 rt->rt_gw4 = ort->rt_gw4; 2749 else if (rt->rt_gw_family == AF_INET6) 2750 rt->rt_gw6 = ort->rt_gw6; 2751 2752 INIT_LIST_HEAD(&rt->rt_uncached); 2753 } 2754 2755 dst_release(dst_orig); 2756 2757 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2758 } 2759 2760 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2761 const struct sock *sk) 2762 { 2763 struct rtable *rt = __ip_route_output_key(net, flp4); 2764 2765 if (IS_ERR(rt)) 2766 return rt; 2767 2768 if (flp4->flowi4_proto) 2769 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2770 flowi4_to_flowi(flp4), 2771 sk, 0); 2772 2773 return rt; 2774 } 2775 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2776 2777 struct rtable *ip_route_output_tunnel(struct sk_buff *skb, 2778 struct net_device *dev, 2779 struct net *net, __be32 *saddr, 2780 const struct ip_tunnel_info *info, 2781 u8 protocol, bool use_cache) 2782 { 2783 #ifdef CONFIG_DST_CACHE 2784 struct dst_cache *dst_cache; 2785 #endif 2786 struct rtable *rt = NULL; 2787 struct flowi4 fl4; 2788 __u8 tos; 2789 2790 #ifdef CONFIG_DST_CACHE 2791 dst_cache = (struct dst_cache *)&info->dst_cache; 2792 if (use_cache) { 2793 rt = dst_cache_get_ip4(dst_cache, saddr); 2794 if (rt) 2795 return rt; 2796 } 2797 #endif 2798 memset(&fl4, 0, sizeof(fl4)); 2799 fl4.flowi4_mark = skb->mark; 2800 fl4.flowi4_proto = protocol; 2801 fl4.daddr = info->key.u.ipv4.dst; 2802 fl4.saddr = info->key.u.ipv4.src; 2803 tos = info->key.tos; 2804 fl4.flowi4_tos = RT_TOS(tos); 2805 2806 rt = ip_route_output_key(net, &fl4); 2807 if (IS_ERR(rt)) { 2808 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr); 2809 return ERR_PTR(-ENETUNREACH); 2810 } 2811 if (rt->dst.dev == dev) { /* is this necessary? */ 2812 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr); 2813 ip_rt_put(rt); 2814 return ERR_PTR(-ELOOP); 2815 } 2816 #ifdef CONFIG_DST_CACHE 2817 if (use_cache) 2818 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr); 2819 #endif 2820 *saddr = fl4.saddr; 2821 return rt; 2822 } 2823 EXPORT_SYMBOL_GPL(ip_route_output_tunnel); 2824 2825 /* called with rcu_read_lock held */ 2826 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2827 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2828 struct sk_buff *skb, u32 portid, u32 seq, 2829 unsigned int flags) 2830 { 2831 struct rtmsg *r; 2832 struct nlmsghdr *nlh; 2833 unsigned long expires = 0; 2834 u32 error; 2835 u32 metrics[RTAX_MAX]; 2836 2837 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2838 if (!nlh) 2839 return -EMSGSIZE; 2840 2841 r = nlmsg_data(nlh); 2842 r->rtm_family = AF_INET; 2843 r->rtm_dst_len = 32; 2844 r->rtm_src_len = 0; 2845 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2846 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2847 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2848 goto nla_put_failure; 2849 r->rtm_type = rt->rt_type; 2850 r->rtm_scope = RT_SCOPE_UNIVERSE; 2851 r->rtm_protocol = RTPROT_UNSPEC; 2852 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2853 if (rt->rt_flags & RTCF_NOTIFY) 2854 r->rtm_flags |= RTM_F_NOTIFY; 2855 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2856 r->rtm_flags |= RTCF_DOREDIRECT; 2857 2858 if (nla_put_in_addr(skb, RTA_DST, dst)) 2859 goto nla_put_failure; 2860 if (src) { 2861 r->rtm_src_len = 32; 2862 if (nla_put_in_addr(skb, RTA_SRC, src)) 2863 goto nla_put_failure; 2864 } 2865 if (rt->dst.dev && 2866 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2867 goto nla_put_failure; 2868 #ifdef CONFIG_IP_ROUTE_CLASSID 2869 if (rt->dst.tclassid && 2870 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2871 goto nla_put_failure; 2872 #endif 2873 if (fl4 && !rt_is_input_route(rt) && 2874 fl4->saddr != src) { 2875 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2876 goto nla_put_failure; 2877 } 2878 if (rt->rt_uses_gateway) { 2879 if (rt->rt_gw_family == AF_INET && 2880 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2881 goto nla_put_failure; 2882 } else if (rt->rt_gw_family == AF_INET6) { 2883 int alen = sizeof(struct in6_addr); 2884 struct nlattr *nla; 2885 struct rtvia *via; 2886 2887 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2888 if (!nla) 2889 goto nla_put_failure; 2890 2891 via = nla_data(nla); 2892 via->rtvia_family = AF_INET6; 2893 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2894 } 2895 } 2896 2897 expires = rt->dst.expires; 2898 if (expires) { 2899 unsigned long now = jiffies; 2900 2901 if (time_before(now, expires)) 2902 expires -= now; 2903 else 2904 expires = 0; 2905 } 2906 2907 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2908 if (rt->rt_pmtu && expires) 2909 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2910 if (rt->rt_mtu_locked && expires) 2911 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2912 if (rtnetlink_put_metrics(skb, metrics) < 0) 2913 goto nla_put_failure; 2914 2915 if (fl4) { 2916 if (fl4->flowi4_mark && 2917 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2918 goto nla_put_failure; 2919 2920 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2921 nla_put_u32(skb, RTA_UID, 2922 from_kuid_munged(current_user_ns(), 2923 fl4->flowi4_uid))) 2924 goto nla_put_failure; 2925 2926 if (rt_is_input_route(rt)) { 2927 #ifdef CONFIG_IP_MROUTE 2928 if (ipv4_is_multicast(dst) && 2929 !ipv4_is_local_multicast(dst) && 2930 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2931 int err = ipmr_get_route(net, skb, 2932 fl4->saddr, fl4->daddr, 2933 r, portid); 2934 2935 if (err <= 0) { 2936 if (err == 0) 2937 return 0; 2938 goto nla_put_failure; 2939 } 2940 } else 2941 #endif 2942 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2943 goto nla_put_failure; 2944 } 2945 } 2946 2947 error = rt->dst.error; 2948 2949 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2950 goto nla_put_failure; 2951 2952 nlmsg_end(skb, nlh); 2953 return 0; 2954 2955 nla_put_failure: 2956 nlmsg_cancel(skb, nlh); 2957 return -EMSGSIZE; 2958 } 2959 2960 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2961 struct netlink_callback *cb, u32 table_id, 2962 struct fnhe_hash_bucket *bucket, int genid, 2963 int *fa_index, int fa_start, unsigned int flags) 2964 { 2965 int i; 2966 2967 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2968 struct fib_nh_exception *fnhe; 2969 2970 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2971 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2972 struct rtable *rt; 2973 int err; 2974 2975 if (*fa_index < fa_start) 2976 goto next; 2977 2978 if (fnhe->fnhe_genid != genid) 2979 goto next; 2980 2981 if (fnhe->fnhe_expires && 2982 time_after(jiffies, fnhe->fnhe_expires)) 2983 goto next; 2984 2985 rt = rcu_dereference(fnhe->fnhe_rth_input); 2986 if (!rt) 2987 rt = rcu_dereference(fnhe->fnhe_rth_output); 2988 if (!rt) 2989 goto next; 2990 2991 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2992 table_id, NULL, skb, 2993 NETLINK_CB(cb->skb).portid, 2994 cb->nlh->nlmsg_seq, flags); 2995 if (err) 2996 return err; 2997 next: 2998 (*fa_index)++; 2999 } 3000 } 3001 3002 return 0; 3003 } 3004 3005 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 3006 u32 table_id, struct fib_info *fi, 3007 int *fa_index, int fa_start, unsigned int flags) 3008 { 3009 struct net *net = sock_net(cb->skb->sk); 3010 int nhsel, genid = fnhe_genid(net); 3011 3012 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 3013 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 3014 struct fnhe_hash_bucket *bucket; 3015 int err; 3016 3017 if (nhc->nhc_flags & RTNH_F_DEAD) 3018 continue; 3019 3020 rcu_read_lock(); 3021 bucket = rcu_dereference(nhc->nhc_exceptions); 3022 err = 0; 3023 if (bucket) 3024 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 3025 genid, fa_index, fa_start, 3026 flags); 3027 rcu_read_unlock(); 3028 if (err) 3029 return err; 3030 } 3031 3032 return 0; 3033 } 3034 3035 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 3036 u8 ip_proto, __be16 sport, 3037 __be16 dport) 3038 { 3039 struct sk_buff *skb; 3040 struct iphdr *iph; 3041 3042 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3043 if (!skb) 3044 return NULL; 3045 3046 /* Reserve room for dummy headers, this skb can pass 3047 * through good chunk of routing engine. 3048 */ 3049 skb_reset_mac_header(skb); 3050 skb_reset_network_header(skb); 3051 skb->protocol = htons(ETH_P_IP); 3052 iph = skb_put(skb, sizeof(struct iphdr)); 3053 iph->protocol = ip_proto; 3054 iph->saddr = src; 3055 iph->daddr = dst; 3056 iph->version = 0x4; 3057 iph->frag_off = 0; 3058 iph->ihl = 0x5; 3059 skb_set_transport_header(skb, skb->len); 3060 3061 switch (iph->protocol) { 3062 case IPPROTO_UDP: { 3063 struct udphdr *udph; 3064 3065 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3066 udph->source = sport; 3067 udph->dest = dport; 3068 udph->len = sizeof(struct udphdr); 3069 udph->check = 0; 3070 break; 3071 } 3072 case IPPROTO_TCP: { 3073 struct tcphdr *tcph; 3074 3075 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3076 tcph->source = sport; 3077 tcph->dest = dport; 3078 tcph->doff = sizeof(struct tcphdr) / 4; 3079 tcph->rst = 1; 3080 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3081 src, dst, 0); 3082 break; 3083 } 3084 case IPPROTO_ICMP: { 3085 struct icmphdr *icmph; 3086 3087 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3088 icmph->type = ICMP_ECHO; 3089 icmph->code = 0; 3090 } 3091 } 3092 3093 return skb; 3094 } 3095 3096 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3097 const struct nlmsghdr *nlh, 3098 struct nlattr **tb, 3099 struct netlink_ext_ack *extack) 3100 { 3101 struct rtmsg *rtm; 3102 int i, err; 3103 3104 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3105 NL_SET_ERR_MSG(extack, 3106 "ipv4: Invalid header for route get request"); 3107 return -EINVAL; 3108 } 3109 3110 if (!netlink_strict_get_check(skb)) 3111 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3112 rtm_ipv4_policy, extack); 3113 3114 rtm = nlmsg_data(nlh); 3115 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3116 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3117 rtm->rtm_table || rtm->rtm_protocol || 3118 rtm->rtm_scope || rtm->rtm_type) { 3119 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3120 return -EINVAL; 3121 } 3122 3123 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3124 RTM_F_LOOKUP_TABLE | 3125 RTM_F_FIB_MATCH)) { 3126 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3127 return -EINVAL; 3128 } 3129 3130 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3131 rtm_ipv4_policy, extack); 3132 if (err) 3133 return err; 3134 3135 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3136 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3137 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3138 return -EINVAL; 3139 } 3140 3141 for (i = 0; i <= RTA_MAX; i++) { 3142 if (!tb[i]) 3143 continue; 3144 3145 switch (i) { 3146 case RTA_IIF: 3147 case RTA_OIF: 3148 case RTA_SRC: 3149 case RTA_DST: 3150 case RTA_IP_PROTO: 3151 case RTA_SPORT: 3152 case RTA_DPORT: 3153 case RTA_MARK: 3154 case RTA_UID: 3155 break; 3156 default: 3157 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3158 return -EINVAL; 3159 } 3160 } 3161 3162 return 0; 3163 } 3164 3165 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3166 struct netlink_ext_ack *extack) 3167 { 3168 struct net *net = sock_net(in_skb->sk); 3169 struct nlattr *tb[RTA_MAX+1]; 3170 u32 table_id = RT_TABLE_MAIN; 3171 __be16 sport = 0, dport = 0; 3172 struct fib_result res = {}; 3173 u8 ip_proto = IPPROTO_UDP; 3174 struct rtable *rt = NULL; 3175 struct sk_buff *skb; 3176 struct rtmsg *rtm; 3177 struct flowi4 fl4 = {}; 3178 __be32 dst = 0; 3179 __be32 src = 0; 3180 kuid_t uid; 3181 u32 iif; 3182 int err; 3183 int mark; 3184 3185 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3186 if (err < 0) 3187 return err; 3188 3189 rtm = nlmsg_data(nlh); 3190 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3191 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3192 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3193 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3194 if (tb[RTA_UID]) 3195 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3196 else 3197 uid = (iif ? INVALID_UID : current_uid()); 3198 3199 if (tb[RTA_IP_PROTO]) { 3200 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3201 &ip_proto, AF_INET, extack); 3202 if (err) 3203 return err; 3204 } 3205 3206 if (tb[RTA_SPORT]) 3207 sport = nla_get_be16(tb[RTA_SPORT]); 3208 3209 if (tb[RTA_DPORT]) 3210 dport = nla_get_be16(tb[RTA_DPORT]); 3211 3212 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3213 if (!skb) 3214 return -ENOBUFS; 3215 3216 fl4.daddr = dst; 3217 fl4.saddr = src; 3218 fl4.flowi4_tos = rtm->rtm_tos; 3219 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3220 fl4.flowi4_mark = mark; 3221 fl4.flowi4_uid = uid; 3222 if (sport) 3223 fl4.fl4_sport = sport; 3224 if (dport) 3225 fl4.fl4_dport = dport; 3226 fl4.flowi4_proto = ip_proto; 3227 3228 rcu_read_lock(); 3229 3230 if (iif) { 3231 struct net_device *dev; 3232 3233 dev = dev_get_by_index_rcu(net, iif); 3234 if (!dev) { 3235 err = -ENODEV; 3236 goto errout_rcu; 3237 } 3238 3239 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3240 skb->dev = dev; 3241 skb->mark = mark; 3242 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 3243 dev, &res); 3244 3245 rt = skb_rtable(skb); 3246 if (err == 0 && rt->dst.error) 3247 err = -rt->dst.error; 3248 } else { 3249 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3250 skb->dev = net->loopback_dev; 3251 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3252 err = 0; 3253 if (IS_ERR(rt)) 3254 err = PTR_ERR(rt); 3255 else 3256 skb_dst_set(skb, &rt->dst); 3257 } 3258 3259 if (err) 3260 goto errout_rcu; 3261 3262 if (rtm->rtm_flags & RTM_F_NOTIFY) 3263 rt->rt_flags |= RTCF_NOTIFY; 3264 3265 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3266 table_id = res.table ? res.table->tb_id : 0; 3267 3268 /* reset skb for netlink reply msg */ 3269 skb_trim(skb, 0); 3270 skb_reset_network_header(skb); 3271 skb_reset_transport_header(skb); 3272 skb_reset_mac_header(skb); 3273 3274 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3275 struct fib_rt_info fri; 3276 3277 if (!res.fi) { 3278 err = fib_props[res.type].error; 3279 if (!err) 3280 err = -EHOSTUNREACH; 3281 goto errout_rcu; 3282 } 3283 fri.fi = res.fi; 3284 fri.tb_id = table_id; 3285 fri.dst = res.prefix; 3286 fri.dst_len = res.prefixlen; 3287 fri.tos = fl4.flowi4_tos; 3288 fri.type = rt->rt_type; 3289 fri.offload = 0; 3290 fri.trap = 0; 3291 if (res.fa_head) { 3292 struct fib_alias *fa; 3293 3294 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) { 3295 u8 slen = 32 - fri.dst_len; 3296 3297 if (fa->fa_slen == slen && 3298 fa->tb_id == fri.tb_id && 3299 fa->fa_tos == fri.tos && 3300 fa->fa_info == res.fi && 3301 fa->fa_type == fri.type) { 3302 fri.offload = fa->offload; 3303 fri.trap = fa->trap; 3304 break; 3305 } 3306 } 3307 } 3308 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3309 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0); 3310 } else { 3311 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3312 NETLINK_CB(in_skb).portid, 3313 nlh->nlmsg_seq, 0); 3314 } 3315 if (err < 0) 3316 goto errout_rcu; 3317 3318 rcu_read_unlock(); 3319 3320 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3321 3322 errout_free: 3323 return err; 3324 errout_rcu: 3325 rcu_read_unlock(); 3326 kfree_skb(skb); 3327 goto errout_free; 3328 } 3329 3330 void ip_rt_multicast_event(struct in_device *in_dev) 3331 { 3332 rt_cache_flush(dev_net(in_dev->dev)); 3333 } 3334 3335 #ifdef CONFIG_SYSCTL 3336 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3337 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3338 static int ip_rt_gc_elasticity __read_mostly = 8; 3339 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3340 3341 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3342 void __user *buffer, 3343 size_t *lenp, loff_t *ppos) 3344 { 3345 struct net *net = (struct net *)__ctl->extra1; 3346 3347 if (write) { 3348 rt_cache_flush(net); 3349 fnhe_genid_bump(net); 3350 return 0; 3351 } 3352 3353 return -EINVAL; 3354 } 3355 3356 static struct ctl_table ipv4_route_table[] = { 3357 { 3358 .procname = "gc_thresh", 3359 .data = &ipv4_dst_ops.gc_thresh, 3360 .maxlen = sizeof(int), 3361 .mode = 0644, 3362 .proc_handler = proc_dointvec, 3363 }, 3364 { 3365 .procname = "max_size", 3366 .data = &ip_rt_max_size, 3367 .maxlen = sizeof(int), 3368 .mode = 0644, 3369 .proc_handler = proc_dointvec, 3370 }, 3371 { 3372 /* Deprecated. Use gc_min_interval_ms */ 3373 3374 .procname = "gc_min_interval", 3375 .data = &ip_rt_gc_min_interval, 3376 .maxlen = sizeof(int), 3377 .mode = 0644, 3378 .proc_handler = proc_dointvec_jiffies, 3379 }, 3380 { 3381 .procname = "gc_min_interval_ms", 3382 .data = &ip_rt_gc_min_interval, 3383 .maxlen = sizeof(int), 3384 .mode = 0644, 3385 .proc_handler = proc_dointvec_ms_jiffies, 3386 }, 3387 { 3388 .procname = "gc_timeout", 3389 .data = &ip_rt_gc_timeout, 3390 .maxlen = sizeof(int), 3391 .mode = 0644, 3392 .proc_handler = proc_dointvec_jiffies, 3393 }, 3394 { 3395 .procname = "gc_interval", 3396 .data = &ip_rt_gc_interval, 3397 .maxlen = sizeof(int), 3398 .mode = 0644, 3399 .proc_handler = proc_dointvec_jiffies, 3400 }, 3401 { 3402 .procname = "redirect_load", 3403 .data = &ip_rt_redirect_load, 3404 .maxlen = sizeof(int), 3405 .mode = 0644, 3406 .proc_handler = proc_dointvec, 3407 }, 3408 { 3409 .procname = "redirect_number", 3410 .data = &ip_rt_redirect_number, 3411 .maxlen = sizeof(int), 3412 .mode = 0644, 3413 .proc_handler = proc_dointvec, 3414 }, 3415 { 3416 .procname = "redirect_silence", 3417 .data = &ip_rt_redirect_silence, 3418 .maxlen = sizeof(int), 3419 .mode = 0644, 3420 .proc_handler = proc_dointvec, 3421 }, 3422 { 3423 .procname = "error_cost", 3424 .data = &ip_rt_error_cost, 3425 .maxlen = sizeof(int), 3426 .mode = 0644, 3427 .proc_handler = proc_dointvec, 3428 }, 3429 { 3430 .procname = "error_burst", 3431 .data = &ip_rt_error_burst, 3432 .maxlen = sizeof(int), 3433 .mode = 0644, 3434 .proc_handler = proc_dointvec, 3435 }, 3436 { 3437 .procname = "gc_elasticity", 3438 .data = &ip_rt_gc_elasticity, 3439 .maxlen = sizeof(int), 3440 .mode = 0644, 3441 .proc_handler = proc_dointvec, 3442 }, 3443 { 3444 .procname = "mtu_expires", 3445 .data = &ip_rt_mtu_expires, 3446 .maxlen = sizeof(int), 3447 .mode = 0644, 3448 .proc_handler = proc_dointvec_jiffies, 3449 }, 3450 { 3451 .procname = "min_pmtu", 3452 .data = &ip_rt_min_pmtu, 3453 .maxlen = sizeof(int), 3454 .mode = 0644, 3455 .proc_handler = proc_dointvec_minmax, 3456 .extra1 = &ip_min_valid_pmtu, 3457 }, 3458 { 3459 .procname = "min_adv_mss", 3460 .data = &ip_rt_min_advmss, 3461 .maxlen = sizeof(int), 3462 .mode = 0644, 3463 .proc_handler = proc_dointvec, 3464 }, 3465 { } 3466 }; 3467 3468 static const char ipv4_route_flush_procname[] = "flush"; 3469 3470 static struct ctl_table ipv4_route_flush_table[] = { 3471 { 3472 .procname = ipv4_route_flush_procname, 3473 .maxlen = sizeof(int), 3474 .mode = 0200, 3475 .proc_handler = ipv4_sysctl_rtcache_flush, 3476 }, 3477 { }, 3478 }; 3479 3480 static __net_init int sysctl_route_net_init(struct net *net) 3481 { 3482 struct ctl_table *tbl; 3483 3484 tbl = ipv4_route_flush_table; 3485 if (!net_eq(net, &init_net)) { 3486 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3487 if (!tbl) 3488 goto err_dup; 3489 3490 /* Don't export non-whitelisted sysctls to unprivileged users */ 3491 if (net->user_ns != &init_user_ns) { 3492 if (tbl[0].procname != ipv4_route_flush_procname) 3493 tbl[0].procname = NULL; 3494 } 3495 } 3496 tbl[0].extra1 = net; 3497 3498 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3499 if (!net->ipv4.route_hdr) 3500 goto err_reg; 3501 return 0; 3502 3503 err_reg: 3504 if (tbl != ipv4_route_flush_table) 3505 kfree(tbl); 3506 err_dup: 3507 return -ENOMEM; 3508 } 3509 3510 static __net_exit void sysctl_route_net_exit(struct net *net) 3511 { 3512 struct ctl_table *tbl; 3513 3514 tbl = net->ipv4.route_hdr->ctl_table_arg; 3515 unregister_net_sysctl_table(net->ipv4.route_hdr); 3516 BUG_ON(tbl == ipv4_route_flush_table); 3517 kfree(tbl); 3518 } 3519 3520 static __net_initdata struct pernet_operations sysctl_route_ops = { 3521 .init = sysctl_route_net_init, 3522 .exit = sysctl_route_net_exit, 3523 }; 3524 #endif 3525 3526 static __net_init int rt_genid_init(struct net *net) 3527 { 3528 atomic_set(&net->ipv4.rt_genid, 0); 3529 atomic_set(&net->fnhe_genid, 0); 3530 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3531 return 0; 3532 } 3533 3534 static __net_initdata struct pernet_operations rt_genid_ops = { 3535 .init = rt_genid_init, 3536 }; 3537 3538 static int __net_init ipv4_inetpeer_init(struct net *net) 3539 { 3540 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3541 3542 if (!bp) 3543 return -ENOMEM; 3544 inet_peer_base_init(bp); 3545 net->ipv4.peers = bp; 3546 return 0; 3547 } 3548 3549 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3550 { 3551 struct inet_peer_base *bp = net->ipv4.peers; 3552 3553 net->ipv4.peers = NULL; 3554 inetpeer_invalidate_tree(bp); 3555 kfree(bp); 3556 } 3557 3558 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3559 .init = ipv4_inetpeer_init, 3560 .exit = ipv4_inetpeer_exit, 3561 }; 3562 3563 #ifdef CONFIG_IP_ROUTE_CLASSID 3564 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3565 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3566 3567 int __init ip_rt_init(void) 3568 { 3569 int cpu; 3570 3571 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents), 3572 GFP_KERNEL); 3573 if (!ip_idents) 3574 panic("IP: failed to allocate ip_idents\n"); 3575 3576 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3577 3578 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3579 if (!ip_tstamps) 3580 panic("IP: failed to allocate ip_tstamps\n"); 3581 3582 for_each_possible_cpu(cpu) { 3583 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3584 3585 INIT_LIST_HEAD(&ul->head); 3586 spin_lock_init(&ul->lock); 3587 } 3588 #ifdef CONFIG_IP_ROUTE_CLASSID 3589 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3590 if (!ip_rt_acct) 3591 panic("IP: failed to allocate ip_rt_acct\n"); 3592 #endif 3593 3594 ipv4_dst_ops.kmem_cachep = 3595 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3596 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3597 3598 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3599 3600 if (dst_entries_init(&ipv4_dst_ops) < 0) 3601 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3602 3603 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3604 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3605 3606 ipv4_dst_ops.gc_thresh = ~0; 3607 ip_rt_max_size = INT_MAX; 3608 3609 devinet_init(); 3610 ip_fib_init(); 3611 3612 if (ip_rt_proc_init()) 3613 pr_err("Unable to create route proc files\n"); 3614 #ifdef CONFIG_XFRM 3615 xfrm_init(); 3616 xfrm4_init(); 3617 #endif 3618 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3619 RTNL_FLAG_DOIT_UNLOCKED); 3620 3621 #ifdef CONFIG_SYSCTL 3622 register_pernet_subsys(&sysctl_route_ops); 3623 #endif 3624 register_pernet_subsys(&rt_genid_ops); 3625 register_pernet_subsys(&ipv4_inetpeer_ops); 3626 return 0; 3627 } 3628 3629 #ifdef CONFIG_SYSCTL 3630 /* 3631 * We really need to sanitize the damn ipv4 init order, then all 3632 * this nonsense will go away. 3633 */ 3634 void __init ip_static_sysctl_init(void) 3635 { 3636 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3637 } 3638 #endif 3639