1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * ROUTE - implementation of the IP router. 8 * 9 * Authors: Ross Biro 10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * Alan Cox, <gw4pts@gw4pts.ampr.org> 12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 14 * 15 * Fixes: 16 * Alan Cox : Verify area fixes. 17 * Alan Cox : cli() protects routing changes 18 * Rui Oliveira : ICMP routing table updates 19 * (rco@di.uminho.pt) Routing table insertion and update 20 * Linus Torvalds : Rewrote bits to be sensible 21 * Alan Cox : Added BSD route gw semantics 22 * Alan Cox : Super /proc >4K 23 * Alan Cox : MTU in route table 24 * Alan Cox : MSS actually. Also added the window 25 * clamper. 26 * Sam Lantinga : Fixed route matching in rt_del() 27 * Alan Cox : Routing cache support. 28 * Alan Cox : Removed compatibility cruft. 29 * Alan Cox : RTF_REJECT support. 30 * Alan Cox : TCP irtt support. 31 * Jonathan Naylor : Added Metric support. 32 * Miquel van Smoorenburg : BSD API fixes. 33 * Miquel van Smoorenburg : Metrics. 34 * Alan Cox : Use __u32 properly 35 * Alan Cox : Aligned routing errors more closely with BSD 36 * our system is still very different. 37 * Alan Cox : Faster /proc handling 38 * Alexey Kuznetsov : Massive rework to support tree based routing, 39 * routing caches and better behaviour. 40 * 41 * Olaf Erb : irtt wasn't being copied right. 42 * Bjorn Ekwall : Kerneld route support. 43 * Alan Cox : Multicast fixed (I hope) 44 * Pavel Krauz : Limited broadcast fixed 45 * Mike McLagan : Routing by source 46 * Alexey Kuznetsov : End of old history. Split to fib.c and 47 * route.c and rewritten from scratch. 48 * Andi Kleen : Load-limit warning messages. 49 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 53 * Marc Boucher : routing by fwmark 54 * Robert Olsson : Added rt_cache statistics 55 * Arnaldo C. Melo : Convert proc stuff to seq_file 56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 58 * Ilia Sotnikov : Removed TOS from hash calculations 59 */ 60 61 #define pr_fmt(fmt) "IPv4: " fmt 62 63 #include <linux/module.h> 64 #include <linux/uaccess.h> 65 #include <linux/bitops.h> 66 #include <linux/types.h> 67 #include <linux/kernel.h> 68 #include <linux/mm.h> 69 #include <linux/string.h> 70 #include <linux/socket.h> 71 #include <linux/sockios.h> 72 #include <linux/errno.h> 73 #include <linux/in.h> 74 #include <linux/inet.h> 75 #include <linux/netdevice.h> 76 #include <linux/proc_fs.h> 77 #include <linux/init.h> 78 #include <linux/skbuff.h> 79 #include <linux/inetdevice.h> 80 #include <linux/igmp.h> 81 #include <linux/pkt_sched.h> 82 #include <linux/mroute.h> 83 #include <linux/netfilter_ipv4.h> 84 #include <linux/random.h> 85 #include <linux/rcupdate.h> 86 #include <linux/times.h> 87 #include <linux/slab.h> 88 #include <linux/jhash.h> 89 #include <net/dst.h> 90 #include <net/dst_metadata.h> 91 #include <net/net_namespace.h> 92 #include <net/protocol.h> 93 #include <net/ip.h> 94 #include <net/route.h> 95 #include <net/inetpeer.h> 96 #include <net/sock.h> 97 #include <net/ip_fib.h> 98 #include <net/nexthop.h> 99 #include <net/arp.h> 100 #include <net/tcp.h> 101 #include <net/icmp.h> 102 #include <net/xfrm.h> 103 #include <net/lwtunnel.h> 104 #include <net/netevent.h> 105 #include <net/rtnetlink.h> 106 #ifdef CONFIG_SYSCTL 107 #include <linux/sysctl.h> 108 #endif 109 #include <net/secure_seq.h> 110 #include <net/ip_tunnels.h> 111 #include <net/l3mdev.h> 112 113 #include "fib_lookup.h" 114 115 #define RT_FL_TOS(oldflp4) \ 116 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 117 118 #define RT_GC_TIMEOUT (300*HZ) 119 120 static int ip_rt_max_size; 121 static int ip_rt_redirect_number __read_mostly = 9; 122 static int ip_rt_redirect_load __read_mostly = HZ / 50; 123 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 124 static int ip_rt_error_cost __read_mostly = HZ; 125 static int ip_rt_error_burst __read_mostly = 5 * HZ; 126 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 127 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 128 static int ip_rt_min_advmss __read_mostly = 256; 129 130 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 131 132 /* 133 * Interface to generic destination cache. 134 */ 135 136 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 137 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 138 static unsigned int ipv4_mtu(const struct dst_entry *dst); 139 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 140 static void ipv4_link_failure(struct sk_buff *skb); 141 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 142 struct sk_buff *skb, u32 mtu); 143 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 144 struct sk_buff *skb); 145 static void ipv4_dst_destroy(struct dst_entry *dst); 146 147 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 148 { 149 WARN_ON(1); 150 return NULL; 151 } 152 153 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 154 struct sk_buff *skb, 155 const void *daddr); 156 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr); 157 158 static struct dst_ops ipv4_dst_ops = { 159 .family = AF_INET, 160 .check = ipv4_dst_check, 161 .default_advmss = ipv4_default_advmss, 162 .mtu = ipv4_mtu, 163 .cow_metrics = ipv4_cow_metrics, 164 .destroy = ipv4_dst_destroy, 165 .negative_advice = ipv4_negative_advice, 166 .link_failure = ipv4_link_failure, 167 .update_pmtu = ip_rt_update_pmtu, 168 .redirect = ip_do_redirect, 169 .local_out = __ip_local_out, 170 .neigh_lookup = ipv4_neigh_lookup, 171 .confirm_neigh = ipv4_confirm_neigh, 172 }; 173 174 #define ECN_OR_COST(class) TC_PRIO_##class 175 176 const __u8 ip_tos2prio[16] = { 177 TC_PRIO_BESTEFFORT, 178 ECN_OR_COST(BESTEFFORT), 179 TC_PRIO_BESTEFFORT, 180 ECN_OR_COST(BESTEFFORT), 181 TC_PRIO_BULK, 182 ECN_OR_COST(BULK), 183 TC_PRIO_BULK, 184 ECN_OR_COST(BULK), 185 TC_PRIO_INTERACTIVE, 186 ECN_OR_COST(INTERACTIVE), 187 TC_PRIO_INTERACTIVE, 188 ECN_OR_COST(INTERACTIVE), 189 TC_PRIO_INTERACTIVE_BULK, 190 ECN_OR_COST(INTERACTIVE_BULK), 191 TC_PRIO_INTERACTIVE_BULK, 192 ECN_OR_COST(INTERACTIVE_BULK) 193 }; 194 EXPORT_SYMBOL(ip_tos2prio); 195 196 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 197 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 198 199 #ifdef CONFIG_PROC_FS 200 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 201 { 202 if (*pos) 203 return NULL; 204 return SEQ_START_TOKEN; 205 } 206 207 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 208 { 209 ++*pos; 210 return NULL; 211 } 212 213 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 214 { 215 } 216 217 static int rt_cache_seq_show(struct seq_file *seq, void *v) 218 { 219 if (v == SEQ_START_TOKEN) 220 seq_printf(seq, "%-127s\n", 221 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 222 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 223 "HHUptod\tSpecDst"); 224 return 0; 225 } 226 227 static const struct seq_operations rt_cache_seq_ops = { 228 .start = rt_cache_seq_start, 229 .next = rt_cache_seq_next, 230 .stop = rt_cache_seq_stop, 231 .show = rt_cache_seq_show, 232 }; 233 234 static int rt_cache_seq_open(struct inode *inode, struct file *file) 235 { 236 return seq_open(file, &rt_cache_seq_ops); 237 } 238 239 static const struct file_operations rt_cache_seq_fops = { 240 .open = rt_cache_seq_open, 241 .read = seq_read, 242 .llseek = seq_lseek, 243 .release = seq_release, 244 }; 245 246 247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 248 { 249 int cpu; 250 251 if (*pos == 0) 252 return SEQ_START_TOKEN; 253 254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 255 if (!cpu_possible(cpu)) 256 continue; 257 *pos = cpu+1; 258 return &per_cpu(rt_cache_stat, cpu); 259 } 260 return NULL; 261 } 262 263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 264 { 265 int cpu; 266 267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 268 if (!cpu_possible(cpu)) 269 continue; 270 *pos = cpu+1; 271 return &per_cpu(rt_cache_stat, cpu); 272 } 273 return NULL; 274 275 } 276 277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 278 { 279 280 } 281 282 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 283 { 284 struct rt_cache_stat *st = v; 285 286 if (v == SEQ_START_TOKEN) { 287 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"); 288 return 0; 289 } 290 291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 293 dst_entries_get_slow(&ipv4_dst_ops), 294 0, /* st->in_hit */ 295 st->in_slow_tot, 296 st->in_slow_mc, 297 st->in_no_route, 298 st->in_brd, 299 st->in_martian_dst, 300 st->in_martian_src, 301 302 0, /* st->out_hit */ 303 st->out_slow_tot, 304 st->out_slow_mc, 305 306 0, /* st->gc_total */ 307 0, /* st->gc_ignored */ 308 0, /* st->gc_goal_miss */ 309 0, /* st->gc_dst_overflow */ 310 0, /* st->in_hlist_search */ 311 0 /* st->out_hlist_search */ 312 ); 313 return 0; 314 } 315 316 static const struct seq_operations rt_cpu_seq_ops = { 317 .start = rt_cpu_seq_start, 318 .next = rt_cpu_seq_next, 319 .stop = rt_cpu_seq_stop, 320 .show = rt_cpu_seq_show, 321 }; 322 323 324 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 325 { 326 return seq_open(file, &rt_cpu_seq_ops); 327 } 328 329 static const struct file_operations rt_cpu_seq_fops = { 330 .open = rt_cpu_seq_open, 331 .read = seq_read, 332 .llseek = seq_lseek, 333 .release = seq_release, 334 }; 335 336 #ifdef CONFIG_IP_ROUTE_CLASSID 337 static int rt_acct_proc_show(struct seq_file *m, void *v) 338 { 339 struct ip_rt_acct *dst, *src; 340 unsigned int i, j; 341 342 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 343 if (!dst) 344 return -ENOMEM; 345 346 for_each_possible_cpu(i) { 347 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 348 for (j = 0; j < 256; j++) { 349 dst[j].o_bytes += src[j].o_bytes; 350 dst[j].o_packets += src[j].o_packets; 351 dst[j].i_bytes += src[j].i_bytes; 352 dst[j].i_packets += src[j].i_packets; 353 } 354 } 355 356 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 357 kfree(dst); 358 return 0; 359 } 360 #endif 361 362 static int __net_init ip_rt_do_proc_init(struct net *net) 363 { 364 struct proc_dir_entry *pde; 365 366 pde = proc_create("rt_cache", 0444, net->proc_net, 367 &rt_cache_seq_fops); 368 if (!pde) 369 goto err1; 370 371 pde = proc_create("rt_cache", 0444, 372 net->proc_net_stat, &rt_cpu_seq_fops); 373 if (!pde) 374 goto err2; 375 376 #ifdef CONFIG_IP_ROUTE_CLASSID 377 pde = proc_create_single("rt_acct", 0, net->proc_net, 378 rt_acct_proc_show); 379 if (!pde) 380 goto err3; 381 #endif 382 return 0; 383 384 #ifdef CONFIG_IP_ROUTE_CLASSID 385 err3: 386 remove_proc_entry("rt_cache", net->proc_net_stat); 387 #endif 388 err2: 389 remove_proc_entry("rt_cache", net->proc_net); 390 err1: 391 return -ENOMEM; 392 } 393 394 static void __net_exit ip_rt_do_proc_exit(struct net *net) 395 { 396 remove_proc_entry("rt_cache", net->proc_net_stat); 397 remove_proc_entry("rt_cache", net->proc_net); 398 #ifdef CONFIG_IP_ROUTE_CLASSID 399 remove_proc_entry("rt_acct", net->proc_net); 400 #endif 401 } 402 403 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 404 .init = ip_rt_do_proc_init, 405 .exit = ip_rt_do_proc_exit, 406 }; 407 408 static int __init ip_rt_proc_init(void) 409 { 410 return register_pernet_subsys(&ip_rt_proc_ops); 411 } 412 413 #else 414 static inline int ip_rt_proc_init(void) 415 { 416 return 0; 417 } 418 #endif /* CONFIG_PROC_FS */ 419 420 static inline bool rt_is_expired(const struct rtable *rth) 421 { 422 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 423 } 424 425 void rt_cache_flush(struct net *net) 426 { 427 rt_genid_bump_ipv4(net); 428 } 429 430 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 431 struct sk_buff *skb, 432 const void *daddr) 433 { 434 const struct rtable *rt = container_of(dst, struct rtable, dst); 435 struct net_device *dev = dst->dev; 436 struct neighbour *n; 437 438 rcu_read_lock_bh(); 439 440 if (likely(rt->rt_gw_family == AF_INET)) { 441 n = ip_neigh_gw4(dev, rt->rt_gw4); 442 } else if (rt->rt_gw_family == AF_INET6) { 443 n = ip_neigh_gw6(dev, &rt->rt_gw6); 444 } else { 445 __be32 pkey; 446 447 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr); 448 n = ip_neigh_gw4(dev, pkey); 449 } 450 451 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt)) 452 n = NULL; 453 454 rcu_read_unlock_bh(); 455 456 return n; 457 } 458 459 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr) 460 { 461 const struct rtable *rt = container_of(dst, struct rtable, dst); 462 struct net_device *dev = dst->dev; 463 const __be32 *pkey = daddr; 464 465 if (rt->rt_gw_family == AF_INET) { 466 pkey = (const __be32 *)&rt->rt_gw4; 467 } else if (rt->rt_gw_family == AF_INET6) { 468 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6); 469 } else if (!daddr || 470 (rt->rt_flags & 471 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) { 472 return; 473 } 474 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey); 475 } 476 477 #define IP_IDENTS_SZ 2048u 478 479 static atomic_t *ip_idents __read_mostly; 480 static u32 *ip_tstamps __read_mostly; 481 482 /* In order to protect privacy, we add a perturbation to identifiers 483 * if one generator is seldom used. This makes hard for an attacker 484 * to infer how many packets were sent between two points in time. 485 */ 486 u32 ip_idents_reserve(u32 hash, int segs) 487 { 488 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 489 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 490 u32 old = READ_ONCE(*p_tstamp); 491 u32 now = (u32)jiffies; 492 u32 new, delta = 0; 493 494 if (old != now && cmpxchg(p_tstamp, old, now) == old) 495 delta = prandom_u32_max(now - old); 496 497 /* Do not use atomic_add_return() as it makes UBSAN unhappy */ 498 do { 499 old = (u32)atomic_read(p_id); 500 new = old + delta + segs; 501 } while (atomic_cmpxchg(p_id, old, new) != old); 502 503 return new - segs; 504 } 505 EXPORT_SYMBOL(ip_idents_reserve); 506 507 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 508 { 509 u32 hash, id; 510 511 /* Note the following code is not safe, but this is okay. */ 512 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key))) 513 get_random_bytes(&net->ipv4.ip_id_key, 514 sizeof(net->ipv4.ip_id_key)); 515 516 hash = siphash_3u32((__force u32)iph->daddr, 517 (__force u32)iph->saddr, 518 iph->protocol, 519 &net->ipv4.ip_id_key); 520 id = ip_idents_reserve(hash, segs); 521 iph->id = htons(id); 522 } 523 EXPORT_SYMBOL(__ip_select_ident); 524 525 static void __build_flow_key(const struct net *net, struct flowi4 *fl4, 526 const struct sock *sk, 527 const struct iphdr *iph, 528 int oif, u8 tos, 529 u8 prot, u32 mark, int flow_flags) 530 { 531 if (sk) { 532 const struct inet_sock *inet = inet_sk(sk); 533 534 oif = sk->sk_bound_dev_if; 535 mark = sk->sk_mark; 536 tos = RT_CONN_FLAGS(sk); 537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 538 } 539 flowi4_init_output(fl4, oif, mark, tos, 540 RT_SCOPE_UNIVERSE, prot, 541 flow_flags, 542 iph->daddr, iph->saddr, 0, 0, 543 sock_net_uid(net, sk)); 544 } 545 546 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 547 const struct sock *sk) 548 { 549 const struct net *net = dev_net(skb->dev); 550 const struct iphdr *iph = ip_hdr(skb); 551 int oif = skb->dev->ifindex; 552 u8 tos = RT_TOS(iph->tos); 553 u8 prot = iph->protocol; 554 u32 mark = skb->mark; 555 556 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0); 557 } 558 559 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 560 { 561 const struct inet_sock *inet = inet_sk(sk); 562 const struct ip_options_rcu *inet_opt; 563 __be32 daddr = inet->inet_daddr; 564 565 rcu_read_lock(); 566 inet_opt = rcu_dereference(inet->inet_opt); 567 if (inet_opt && inet_opt->opt.srr) 568 daddr = inet_opt->opt.faddr; 569 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 570 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 571 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 572 inet_sk_flowi_flags(sk), 573 daddr, inet->inet_saddr, 0, 0, sk->sk_uid); 574 rcu_read_unlock(); 575 } 576 577 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 578 const struct sk_buff *skb) 579 { 580 if (skb) 581 build_skb_flow_key(fl4, skb, sk); 582 else 583 build_sk_flow_key(fl4, sk); 584 } 585 586 static DEFINE_SPINLOCK(fnhe_lock); 587 588 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 589 { 590 struct rtable *rt; 591 592 rt = rcu_dereference(fnhe->fnhe_rth_input); 593 if (rt) { 594 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 595 dst_dev_put(&rt->dst); 596 dst_release(&rt->dst); 597 } 598 rt = rcu_dereference(fnhe->fnhe_rth_output); 599 if (rt) { 600 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 601 dst_dev_put(&rt->dst); 602 dst_release(&rt->dst); 603 } 604 } 605 606 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 607 { 608 struct fib_nh_exception *fnhe, *oldest; 609 610 oldest = rcu_dereference(hash->chain); 611 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 612 fnhe = rcu_dereference(fnhe->fnhe_next)) { 613 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 614 oldest = fnhe; 615 } 616 fnhe_flush_routes(oldest); 617 return oldest; 618 } 619 620 static inline u32 fnhe_hashfun(__be32 daddr) 621 { 622 static u32 fnhe_hashrnd __read_mostly; 623 u32 hval; 624 625 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 626 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 627 return hash_32(hval, FNHE_HASH_SHIFT); 628 } 629 630 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 631 { 632 rt->rt_pmtu = fnhe->fnhe_pmtu; 633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked; 634 rt->dst.expires = fnhe->fnhe_expires; 635 636 if (fnhe->fnhe_gw) { 637 rt->rt_flags |= RTCF_REDIRECTED; 638 rt->rt_uses_gateway = 1; 639 rt->rt_gw_family = AF_INET; 640 rt->rt_gw4 = fnhe->fnhe_gw; 641 } 642 } 643 644 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr, 645 __be32 gw, u32 pmtu, bool lock, 646 unsigned long expires) 647 { 648 struct fnhe_hash_bucket *hash; 649 struct fib_nh_exception *fnhe; 650 struct rtable *rt; 651 u32 genid, hval; 652 unsigned int i; 653 int depth; 654 655 genid = fnhe_genid(dev_net(nhc->nhc_dev)); 656 hval = fnhe_hashfun(daddr); 657 658 spin_lock_bh(&fnhe_lock); 659 660 hash = rcu_dereference(nhc->nhc_exceptions); 661 if (!hash) { 662 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC); 663 if (!hash) 664 goto out_unlock; 665 rcu_assign_pointer(nhc->nhc_exceptions, hash); 666 } 667 668 hash += hval; 669 670 depth = 0; 671 for (fnhe = rcu_dereference(hash->chain); fnhe; 672 fnhe = rcu_dereference(fnhe->fnhe_next)) { 673 if (fnhe->fnhe_daddr == daddr) 674 break; 675 depth++; 676 } 677 678 if (fnhe) { 679 if (fnhe->fnhe_genid != genid) 680 fnhe->fnhe_genid = genid; 681 if (gw) 682 fnhe->fnhe_gw = gw; 683 if (pmtu) { 684 fnhe->fnhe_pmtu = pmtu; 685 fnhe->fnhe_mtu_locked = lock; 686 } 687 fnhe->fnhe_expires = max(1UL, expires); 688 /* Update all cached dsts too */ 689 rt = rcu_dereference(fnhe->fnhe_rth_input); 690 if (rt) 691 fill_route_from_fnhe(rt, fnhe); 692 rt = rcu_dereference(fnhe->fnhe_rth_output); 693 if (rt) 694 fill_route_from_fnhe(rt, fnhe); 695 } else { 696 if (depth > FNHE_RECLAIM_DEPTH) 697 fnhe = fnhe_oldest(hash); 698 else { 699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 700 if (!fnhe) 701 goto out_unlock; 702 703 fnhe->fnhe_next = hash->chain; 704 rcu_assign_pointer(hash->chain, fnhe); 705 } 706 fnhe->fnhe_genid = genid; 707 fnhe->fnhe_daddr = daddr; 708 fnhe->fnhe_gw = gw; 709 fnhe->fnhe_pmtu = pmtu; 710 fnhe->fnhe_mtu_locked = lock; 711 fnhe->fnhe_expires = max(1UL, expires); 712 713 /* Exception created; mark the cached routes for the nexthop 714 * stale, so anyone caching it rechecks if this exception 715 * applies to them. 716 */ 717 rt = rcu_dereference(nhc->nhc_rth_input); 718 if (rt) 719 rt->dst.obsolete = DST_OBSOLETE_KILL; 720 721 for_each_possible_cpu(i) { 722 struct rtable __rcu **prt; 723 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i); 724 rt = rcu_dereference(*prt); 725 if (rt) 726 rt->dst.obsolete = DST_OBSOLETE_KILL; 727 } 728 } 729 730 fnhe->fnhe_stamp = jiffies; 731 732 out_unlock: 733 spin_unlock_bh(&fnhe_lock); 734 } 735 736 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 737 bool kill_route) 738 { 739 __be32 new_gw = icmp_hdr(skb)->un.gateway; 740 __be32 old_gw = ip_hdr(skb)->saddr; 741 struct net_device *dev = skb->dev; 742 struct in_device *in_dev; 743 struct fib_result res; 744 struct neighbour *n; 745 struct net *net; 746 747 switch (icmp_hdr(skb)->code & 7) { 748 case ICMP_REDIR_NET: 749 case ICMP_REDIR_NETTOS: 750 case ICMP_REDIR_HOST: 751 case ICMP_REDIR_HOSTTOS: 752 break; 753 754 default: 755 return; 756 } 757 758 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw) 759 return; 760 761 in_dev = __in_dev_get_rcu(dev); 762 if (!in_dev) 763 return; 764 765 net = dev_net(dev); 766 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 767 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 768 ipv4_is_zeronet(new_gw)) 769 goto reject_redirect; 770 771 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 772 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 773 goto reject_redirect; 774 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 775 goto reject_redirect; 776 } else { 777 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 778 goto reject_redirect; 779 } 780 781 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw); 782 if (!n) 783 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); 784 if (!IS_ERR(n)) { 785 if (!(n->nud_state & NUD_VALID)) { 786 neigh_event_send(n, NULL); 787 } else { 788 if (fib_lookup(net, fl4, &res, 0) == 0) { 789 struct fib_nh_common *nhc = FIB_RES_NHC(res); 790 791 update_or_create_fnhe(nhc, fl4->daddr, new_gw, 792 0, false, 793 jiffies + ip_rt_gc_timeout); 794 } 795 if (kill_route) 796 rt->dst.obsolete = DST_OBSOLETE_KILL; 797 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 798 } 799 neigh_release(n); 800 } 801 return; 802 803 reject_redirect: 804 #ifdef CONFIG_IP_ROUTE_VERBOSE 805 if (IN_DEV_LOG_MARTIANS(in_dev)) { 806 const struct iphdr *iph = (const struct iphdr *) skb->data; 807 __be32 daddr = iph->daddr; 808 __be32 saddr = iph->saddr; 809 810 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 811 " Advised path = %pI4 -> %pI4\n", 812 &old_gw, dev->name, &new_gw, 813 &saddr, &daddr); 814 } 815 #endif 816 ; 817 } 818 819 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 820 { 821 struct rtable *rt; 822 struct flowi4 fl4; 823 const struct iphdr *iph = (const struct iphdr *) skb->data; 824 struct net *net = dev_net(skb->dev); 825 int oif = skb->dev->ifindex; 826 u8 tos = RT_TOS(iph->tos); 827 u8 prot = iph->protocol; 828 u32 mark = skb->mark; 829 830 rt = (struct rtable *) dst; 831 832 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0); 833 __ip_do_redirect(rt, skb, &fl4, true); 834 } 835 836 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 837 { 838 struct rtable *rt = (struct rtable *)dst; 839 struct dst_entry *ret = dst; 840 841 if (rt) { 842 if (dst->obsolete > 0) { 843 ip_rt_put(rt); 844 ret = NULL; 845 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 846 rt->dst.expires) { 847 ip_rt_put(rt); 848 ret = NULL; 849 } 850 } 851 return ret; 852 } 853 854 /* 855 * Algorithm: 856 * 1. The first ip_rt_redirect_number redirects are sent 857 * with exponential backoff, then we stop sending them at all, 858 * assuming that the host ignores our redirects. 859 * 2. If we did not see packets requiring redirects 860 * during ip_rt_redirect_silence, we assume that the host 861 * forgot redirected route and start to send redirects again. 862 * 863 * This algorithm is much cheaper and more intelligent than dumb load limiting 864 * in icmp.c. 865 * 866 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 867 * and "frag. need" (breaks PMTU discovery) in icmp.c. 868 */ 869 870 void ip_rt_send_redirect(struct sk_buff *skb) 871 { 872 struct rtable *rt = skb_rtable(skb); 873 struct in_device *in_dev; 874 struct inet_peer *peer; 875 struct net *net; 876 int log_martians; 877 int vif; 878 879 rcu_read_lock(); 880 in_dev = __in_dev_get_rcu(rt->dst.dev); 881 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 882 rcu_read_unlock(); 883 return; 884 } 885 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 886 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 887 rcu_read_unlock(); 888 889 net = dev_net(rt->dst.dev); 890 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 891 if (!peer) { 892 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 893 rt_nexthop(rt, ip_hdr(skb)->daddr)); 894 return; 895 } 896 897 /* No redirected packets during ip_rt_redirect_silence; 898 * reset the algorithm. 899 */ 900 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { 901 peer->rate_tokens = 0; 902 peer->n_redirects = 0; 903 } 904 905 /* Too many ignored redirects; do not send anything 906 * set dst.rate_last to the last seen redirected packet. 907 */ 908 if (peer->n_redirects >= ip_rt_redirect_number) { 909 peer->rate_last = jiffies; 910 goto out_put_peer; 911 } 912 913 /* Check for load limit; set rate_last to the latest sent 914 * redirect. 915 */ 916 if (peer->rate_tokens == 0 || 917 time_after(jiffies, 918 (peer->rate_last + 919 (ip_rt_redirect_load << peer->n_redirects)))) { 920 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 921 922 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 923 peer->rate_last = jiffies; 924 ++peer->n_redirects; 925 #ifdef CONFIG_IP_ROUTE_VERBOSE 926 if (log_martians && 927 peer->n_redirects == ip_rt_redirect_number) 928 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 929 &ip_hdr(skb)->saddr, inet_iif(skb), 930 &ip_hdr(skb)->daddr, &gw); 931 #endif 932 } 933 out_put_peer: 934 inet_putpeer(peer); 935 } 936 937 static int ip_error(struct sk_buff *skb) 938 { 939 struct rtable *rt = skb_rtable(skb); 940 struct net_device *dev = skb->dev; 941 struct in_device *in_dev; 942 struct inet_peer *peer; 943 unsigned long now; 944 struct net *net; 945 bool send; 946 int code; 947 948 if (netif_is_l3_master(skb->dev)) { 949 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); 950 if (!dev) 951 goto out; 952 } 953 954 in_dev = __in_dev_get_rcu(dev); 955 956 /* IP on this device is disabled. */ 957 if (!in_dev) 958 goto out; 959 960 net = dev_net(rt->dst.dev); 961 if (!IN_DEV_FORWARD(in_dev)) { 962 switch (rt->dst.error) { 963 case EHOSTUNREACH: 964 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 965 break; 966 967 case ENETUNREACH: 968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 969 break; 970 } 971 goto out; 972 } 973 974 switch (rt->dst.error) { 975 case EINVAL: 976 default: 977 goto out; 978 case EHOSTUNREACH: 979 code = ICMP_HOST_UNREACH; 980 break; 981 case ENETUNREACH: 982 code = ICMP_NET_UNREACH; 983 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 984 break; 985 case EACCES: 986 code = ICMP_PKT_FILTERED; 987 break; 988 } 989 990 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 991 l3mdev_master_ifindex(skb->dev), 1); 992 993 send = true; 994 if (peer) { 995 now = jiffies; 996 peer->rate_tokens += now - peer->rate_last; 997 if (peer->rate_tokens > ip_rt_error_burst) 998 peer->rate_tokens = ip_rt_error_burst; 999 peer->rate_last = now; 1000 if (peer->rate_tokens >= ip_rt_error_cost) 1001 peer->rate_tokens -= ip_rt_error_cost; 1002 else 1003 send = false; 1004 inet_putpeer(peer); 1005 } 1006 if (send) 1007 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1008 1009 out: kfree_skb(skb); 1010 return 0; 1011 } 1012 1013 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 1014 { 1015 struct dst_entry *dst = &rt->dst; 1016 u32 old_mtu = ipv4_mtu(dst); 1017 struct fib_result res; 1018 bool lock = false; 1019 1020 if (ip_mtu_locked(dst)) 1021 return; 1022 1023 if (old_mtu < mtu) 1024 return; 1025 1026 if (mtu < ip_rt_min_pmtu) { 1027 lock = true; 1028 mtu = min(old_mtu, ip_rt_min_pmtu); 1029 } 1030 1031 if (rt->rt_pmtu == mtu && !lock && 1032 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 1033 return; 1034 1035 rcu_read_lock(); 1036 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 1037 struct fib_nh_common *nhc = FIB_RES_NHC(res); 1038 1039 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock, 1040 jiffies + ip_rt_mtu_expires); 1041 } 1042 rcu_read_unlock(); 1043 } 1044 1045 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 1046 struct sk_buff *skb, u32 mtu) 1047 { 1048 struct rtable *rt = (struct rtable *) dst; 1049 struct flowi4 fl4; 1050 1051 ip_rt_build_flow_key(&fl4, sk, skb); 1052 __ip_rt_update_pmtu(rt, &fl4, mtu); 1053 } 1054 1055 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1056 int oif, u8 protocol) 1057 { 1058 const struct iphdr *iph = (const struct iphdr *) skb->data; 1059 struct flowi4 fl4; 1060 struct rtable *rt; 1061 u32 mark = IP4_REPLY_MARK(net, skb->mark); 1062 1063 __build_flow_key(net, &fl4, NULL, iph, oif, 1064 RT_TOS(iph->tos), protocol, mark, 0); 1065 rt = __ip_route_output_key(net, &fl4); 1066 if (!IS_ERR(rt)) { 1067 __ip_rt_update_pmtu(rt, &fl4, mtu); 1068 ip_rt_put(rt); 1069 } 1070 } 1071 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1072 1073 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1074 { 1075 const struct iphdr *iph = (const struct iphdr *) skb->data; 1076 struct flowi4 fl4; 1077 struct rtable *rt; 1078 1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0); 1080 1081 if (!fl4.flowi4_mark) 1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1083 1084 rt = __ip_route_output_key(sock_net(sk), &fl4); 1085 if (!IS_ERR(rt)) { 1086 __ip_rt_update_pmtu(rt, &fl4, mtu); 1087 ip_rt_put(rt); 1088 } 1089 } 1090 1091 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1092 { 1093 const struct iphdr *iph = (const struct iphdr *) skb->data; 1094 struct flowi4 fl4; 1095 struct rtable *rt; 1096 struct dst_entry *odst = NULL; 1097 bool new = false; 1098 struct net *net = sock_net(sk); 1099 1100 bh_lock_sock(sk); 1101 1102 if (!ip_sk_accept_pmtu(sk)) 1103 goto out; 1104 1105 odst = sk_dst_get(sk); 1106 1107 if (sock_owned_by_user(sk) || !odst) { 1108 __ipv4_sk_update_pmtu(skb, sk, mtu); 1109 goto out; 1110 } 1111 1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1113 1114 rt = (struct rtable *)odst; 1115 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1117 if (IS_ERR(rt)) 1118 goto out; 1119 1120 new = true; 1121 } 1122 1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu); 1124 1125 if (!dst_check(&rt->dst, 0)) { 1126 if (new) 1127 dst_release(&rt->dst); 1128 1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1130 if (IS_ERR(rt)) 1131 goto out; 1132 1133 new = true; 1134 } 1135 1136 if (new) 1137 sk_dst_set(sk, &rt->dst); 1138 1139 out: 1140 bh_unlock_sock(sk); 1141 dst_release(odst); 1142 } 1143 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1144 1145 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1146 int oif, u8 protocol) 1147 { 1148 const struct iphdr *iph = (const struct iphdr *) skb->data; 1149 struct flowi4 fl4; 1150 struct rtable *rt; 1151 1152 __build_flow_key(net, &fl4, NULL, iph, oif, 1153 RT_TOS(iph->tos), protocol, 0, 0); 1154 rt = __ip_route_output_key(net, &fl4); 1155 if (!IS_ERR(rt)) { 1156 __ip_do_redirect(rt, skb, &fl4, false); 1157 ip_rt_put(rt); 1158 } 1159 } 1160 EXPORT_SYMBOL_GPL(ipv4_redirect); 1161 1162 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1163 { 1164 const struct iphdr *iph = (const struct iphdr *) skb->data; 1165 struct flowi4 fl4; 1166 struct rtable *rt; 1167 struct net *net = sock_net(sk); 1168 1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0); 1170 rt = __ip_route_output_key(net, &fl4); 1171 if (!IS_ERR(rt)) { 1172 __ip_do_redirect(rt, skb, &fl4, false); 1173 ip_rt_put(rt); 1174 } 1175 } 1176 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1177 1178 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1179 { 1180 struct rtable *rt = (struct rtable *) dst; 1181 1182 /* All IPV4 dsts are created with ->obsolete set to the value 1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1184 * into this function always. 1185 * 1186 * When a PMTU/redirect information update invalidates a route, 1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1188 * DST_OBSOLETE_DEAD. 1189 */ 1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1191 return NULL; 1192 return dst; 1193 } 1194 1195 static void ipv4_send_dest_unreach(struct sk_buff *skb) 1196 { 1197 struct ip_options opt; 1198 int res; 1199 1200 /* Recompile ip options since IPCB may not be valid anymore. 1201 * Also check we have a reasonable ipv4 header. 1202 */ 1203 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) || 1204 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5) 1205 return; 1206 1207 memset(&opt, 0, sizeof(opt)); 1208 if (ip_hdr(skb)->ihl > 5) { 1209 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4)) 1210 return; 1211 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); 1212 1213 rcu_read_lock(); 1214 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); 1215 rcu_read_unlock(); 1216 1217 if (res) 1218 return; 1219 } 1220 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt); 1221 } 1222 1223 static void ipv4_link_failure(struct sk_buff *skb) 1224 { 1225 struct rtable *rt; 1226 1227 ipv4_send_dest_unreach(skb); 1228 1229 rt = skb_rtable(skb); 1230 if (rt) 1231 dst_set_expires(&rt->dst, 0); 1232 } 1233 1234 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1235 { 1236 pr_debug("%s: %pI4 -> %pI4, %s\n", 1237 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1238 skb->dev ? skb->dev->name : "?"); 1239 kfree_skb(skb); 1240 WARN_ON(1); 1241 return 0; 1242 } 1243 1244 /* 1245 We do not cache source address of outgoing interface, 1246 because it is used only by IP RR, TS and SRR options, 1247 so that it out of fast path. 1248 1249 BTW remember: "addr" is allowed to be not aligned 1250 in IP options! 1251 */ 1252 1253 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1254 { 1255 __be32 src; 1256 1257 if (rt_is_output_route(rt)) 1258 src = ip_hdr(skb)->saddr; 1259 else { 1260 struct fib_result res; 1261 struct iphdr *iph = ip_hdr(skb); 1262 struct flowi4 fl4 = { 1263 .daddr = iph->daddr, 1264 .saddr = iph->saddr, 1265 .flowi4_tos = RT_TOS(iph->tos), 1266 .flowi4_oif = rt->dst.dev->ifindex, 1267 .flowi4_iif = skb->dev->ifindex, 1268 .flowi4_mark = skb->mark, 1269 }; 1270 1271 rcu_read_lock(); 1272 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1273 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res); 1274 else 1275 src = inet_select_addr(rt->dst.dev, 1276 rt_nexthop(rt, iph->daddr), 1277 RT_SCOPE_UNIVERSE); 1278 rcu_read_unlock(); 1279 } 1280 memcpy(addr, &src, 4); 1281 } 1282 1283 #ifdef CONFIG_IP_ROUTE_CLASSID 1284 static void set_class_tag(struct rtable *rt, u32 tag) 1285 { 1286 if (!(rt->dst.tclassid & 0xFFFF)) 1287 rt->dst.tclassid |= tag & 0xFFFF; 1288 if (!(rt->dst.tclassid & 0xFFFF0000)) 1289 rt->dst.tclassid |= tag & 0xFFFF0000; 1290 } 1291 #endif 1292 1293 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1294 { 1295 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); 1296 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, 1297 ip_rt_min_advmss); 1298 1299 return min(advmss, IPV4_MAX_PMTU - header_size); 1300 } 1301 1302 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1303 { 1304 const struct rtable *rt = (const struct rtable *) dst; 1305 unsigned int mtu = rt->rt_pmtu; 1306 1307 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1308 mtu = dst_metric_raw(dst, RTAX_MTU); 1309 1310 if (mtu) 1311 return mtu; 1312 1313 mtu = READ_ONCE(dst->dev->mtu); 1314 1315 if (unlikely(ip_mtu_locked(dst))) { 1316 if (rt->rt_uses_gateway && mtu > 576) 1317 mtu = 576; 1318 } 1319 1320 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1321 1322 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1323 } 1324 1325 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr) 1326 { 1327 struct fnhe_hash_bucket *hash; 1328 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1329 u32 hval = fnhe_hashfun(daddr); 1330 1331 spin_lock_bh(&fnhe_lock); 1332 1333 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1334 lockdep_is_held(&fnhe_lock)); 1335 hash += hval; 1336 1337 fnhe_p = &hash->chain; 1338 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1339 while (fnhe) { 1340 if (fnhe->fnhe_daddr == daddr) { 1341 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1342 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1343 /* set fnhe_daddr to 0 to ensure it won't bind with 1344 * new dsts in rt_bind_exception(). 1345 */ 1346 fnhe->fnhe_daddr = 0; 1347 fnhe_flush_routes(fnhe); 1348 kfree_rcu(fnhe, rcu); 1349 break; 1350 } 1351 fnhe_p = &fnhe->fnhe_next; 1352 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1353 lockdep_is_held(&fnhe_lock)); 1354 } 1355 1356 spin_unlock_bh(&fnhe_lock); 1357 } 1358 1359 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc, 1360 __be32 daddr) 1361 { 1362 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions); 1363 struct fib_nh_exception *fnhe; 1364 u32 hval; 1365 1366 if (!hash) 1367 return NULL; 1368 1369 hval = fnhe_hashfun(daddr); 1370 1371 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1372 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1373 if (fnhe->fnhe_daddr == daddr) { 1374 if (fnhe->fnhe_expires && 1375 time_after(jiffies, fnhe->fnhe_expires)) { 1376 ip_del_fnhe(nhc, daddr); 1377 break; 1378 } 1379 return fnhe; 1380 } 1381 } 1382 return NULL; 1383 } 1384 1385 /* MTU selection: 1386 * 1. mtu on route is locked - use it 1387 * 2. mtu from nexthop exception 1388 * 3. mtu from egress device 1389 */ 1390 1391 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) 1392 { 1393 struct fib_nh_common *nhc = res->nhc; 1394 struct net_device *dev = nhc->nhc_dev; 1395 struct fib_info *fi = res->fi; 1396 u32 mtu = 0; 1397 1398 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || 1399 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) 1400 mtu = fi->fib_mtu; 1401 1402 if (likely(!mtu)) { 1403 struct fib_nh_exception *fnhe; 1404 1405 fnhe = find_exception(nhc, daddr); 1406 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires)) 1407 mtu = fnhe->fnhe_pmtu; 1408 } 1409 1410 if (likely(!mtu)) 1411 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU); 1412 1413 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu); 1414 } 1415 1416 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1417 __be32 daddr, const bool do_cache) 1418 { 1419 bool ret = false; 1420 1421 spin_lock_bh(&fnhe_lock); 1422 1423 if (daddr == fnhe->fnhe_daddr) { 1424 struct rtable __rcu **porig; 1425 struct rtable *orig; 1426 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1427 1428 if (rt_is_input_route(rt)) 1429 porig = &fnhe->fnhe_rth_input; 1430 else 1431 porig = &fnhe->fnhe_rth_output; 1432 orig = rcu_dereference(*porig); 1433 1434 if (fnhe->fnhe_genid != genid) { 1435 fnhe->fnhe_genid = genid; 1436 fnhe->fnhe_gw = 0; 1437 fnhe->fnhe_pmtu = 0; 1438 fnhe->fnhe_expires = 0; 1439 fnhe->fnhe_mtu_locked = false; 1440 fnhe_flush_routes(fnhe); 1441 orig = NULL; 1442 } 1443 fill_route_from_fnhe(rt, fnhe); 1444 if (!rt->rt_gw4) { 1445 rt->rt_gw4 = daddr; 1446 rt->rt_gw_family = AF_INET; 1447 } 1448 1449 if (do_cache) { 1450 dst_hold(&rt->dst); 1451 rcu_assign_pointer(*porig, rt); 1452 if (orig) { 1453 dst_dev_put(&orig->dst); 1454 dst_release(&orig->dst); 1455 } 1456 ret = true; 1457 } 1458 1459 fnhe->fnhe_stamp = jiffies; 1460 } 1461 spin_unlock_bh(&fnhe_lock); 1462 1463 return ret; 1464 } 1465 1466 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 1467 { 1468 struct rtable *orig, *prev, **p; 1469 bool ret = true; 1470 1471 if (rt_is_input_route(rt)) { 1472 p = (struct rtable **)&nhc->nhc_rth_input; 1473 } else { 1474 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 1475 } 1476 orig = *p; 1477 1478 /* hold dst before doing cmpxchg() to avoid race condition 1479 * on this dst 1480 */ 1481 dst_hold(&rt->dst); 1482 prev = cmpxchg(p, orig, rt); 1483 if (prev == orig) { 1484 if (orig) { 1485 rt_add_uncached_list(orig); 1486 dst_release(&orig->dst); 1487 } 1488 } else { 1489 dst_release(&rt->dst); 1490 ret = false; 1491 } 1492 1493 return ret; 1494 } 1495 1496 struct uncached_list { 1497 spinlock_t lock; 1498 struct list_head head; 1499 }; 1500 1501 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1502 1503 void rt_add_uncached_list(struct rtable *rt) 1504 { 1505 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1506 1507 rt->rt_uncached_list = ul; 1508 1509 spin_lock_bh(&ul->lock); 1510 list_add_tail(&rt->rt_uncached, &ul->head); 1511 spin_unlock_bh(&ul->lock); 1512 } 1513 1514 void rt_del_uncached_list(struct rtable *rt) 1515 { 1516 if (!list_empty(&rt->rt_uncached)) { 1517 struct uncached_list *ul = rt->rt_uncached_list; 1518 1519 spin_lock_bh(&ul->lock); 1520 list_del(&rt->rt_uncached); 1521 spin_unlock_bh(&ul->lock); 1522 } 1523 } 1524 1525 static void ipv4_dst_destroy(struct dst_entry *dst) 1526 { 1527 struct rtable *rt = (struct rtable *)dst; 1528 1529 ip_dst_metrics_put(dst); 1530 rt_del_uncached_list(rt); 1531 } 1532 1533 void rt_flush_dev(struct net_device *dev) 1534 { 1535 struct rtable *rt; 1536 int cpu; 1537 1538 for_each_possible_cpu(cpu) { 1539 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1540 1541 spin_lock_bh(&ul->lock); 1542 list_for_each_entry(rt, &ul->head, rt_uncached) { 1543 if (rt->dst.dev != dev) 1544 continue; 1545 rt->dst.dev = blackhole_netdev; 1546 dev_hold(rt->dst.dev); 1547 dev_put(dev); 1548 } 1549 spin_unlock_bh(&ul->lock); 1550 } 1551 } 1552 1553 static bool rt_cache_valid(const struct rtable *rt) 1554 { 1555 return rt && 1556 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1557 !rt_is_expired(rt); 1558 } 1559 1560 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1561 const struct fib_result *res, 1562 struct fib_nh_exception *fnhe, 1563 struct fib_info *fi, u16 type, u32 itag, 1564 const bool do_cache) 1565 { 1566 bool cached = false; 1567 1568 if (fi) { 1569 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1570 1571 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) { 1572 rt->rt_uses_gateway = 1; 1573 rt->rt_gw_family = nhc->nhc_gw_family; 1574 /* only INET and INET6 are supported */ 1575 if (likely(nhc->nhc_gw_family == AF_INET)) 1576 rt->rt_gw4 = nhc->nhc_gw.ipv4; 1577 else 1578 rt->rt_gw6 = nhc->nhc_gw.ipv6; 1579 } 1580 1581 ip_dst_init_metrics(&rt->dst, fi->fib_metrics); 1582 1583 #ifdef CONFIG_IP_ROUTE_CLASSID 1584 if (nhc->nhc_family == AF_INET) { 1585 struct fib_nh *nh; 1586 1587 nh = container_of(nhc, struct fib_nh, nh_common); 1588 rt->dst.tclassid = nh->nh_tclassid; 1589 } 1590 #endif 1591 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 1592 if (unlikely(fnhe)) 1593 cached = rt_bind_exception(rt, fnhe, daddr, do_cache); 1594 else if (do_cache) 1595 cached = rt_cache_route(nhc, rt); 1596 if (unlikely(!cached)) { 1597 /* Routes we intend to cache in nexthop exception or 1598 * FIB nexthop have the DST_NOCACHE bit clear. 1599 * However, if we are unsuccessful at storing this 1600 * route into the cache we really need to set it. 1601 */ 1602 if (!rt->rt_gw4) { 1603 rt->rt_gw_family = AF_INET; 1604 rt->rt_gw4 = daddr; 1605 } 1606 rt_add_uncached_list(rt); 1607 } 1608 } else 1609 rt_add_uncached_list(rt); 1610 1611 #ifdef CONFIG_IP_ROUTE_CLASSID 1612 #ifdef CONFIG_IP_MULTIPLE_TABLES 1613 set_class_tag(rt, res->tclassid); 1614 #endif 1615 set_class_tag(rt, itag); 1616 #endif 1617 } 1618 1619 struct rtable *rt_dst_alloc(struct net_device *dev, 1620 unsigned int flags, u16 type, 1621 bool nopolicy, bool noxfrm, bool will_cache) 1622 { 1623 struct rtable *rt; 1624 1625 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1626 (will_cache ? 0 : DST_HOST) | 1627 (nopolicy ? DST_NOPOLICY : 0) | 1628 (noxfrm ? DST_NOXFRM : 0)); 1629 1630 if (rt) { 1631 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1632 rt->rt_flags = flags; 1633 rt->rt_type = type; 1634 rt->rt_is_input = 0; 1635 rt->rt_iif = 0; 1636 rt->rt_pmtu = 0; 1637 rt->rt_mtu_locked = 0; 1638 rt->rt_uses_gateway = 0; 1639 rt->rt_gw_family = 0; 1640 rt->rt_gw4 = 0; 1641 INIT_LIST_HEAD(&rt->rt_uncached); 1642 1643 rt->dst.output = ip_output; 1644 if (flags & RTCF_LOCAL) 1645 rt->dst.input = ip_local_deliver; 1646 } 1647 1648 return rt; 1649 } 1650 EXPORT_SYMBOL(rt_dst_alloc); 1651 1652 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt) 1653 { 1654 struct rtable *new_rt; 1655 1656 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1657 rt->dst.flags); 1658 1659 if (new_rt) { 1660 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1661 new_rt->rt_flags = rt->rt_flags; 1662 new_rt->rt_type = rt->rt_type; 1663 new_rt->rt_is_input = rt->rt_is_input; 1664 new_rt->rt_iif = rt->rt_iif; 1665 new_rt->rt_pmtu = rt->rt_pmtu; 1666 new_rt->rt_mtu_locked = rt->rt_mtu_locked; 1667 new_rt->rt_gw_family = rt->rt_gw_family; 1668 if (rt->rt_gw_family == AF_INET) 1669 new_rt->rt_gw4 = rt->rt_gw4; 1670 else if (rt->rt_gw_family == AF_INET6) 1671 new_rt->rt_gw6 = rt->rt_gw6; 1672 INIT_LIST_HEAD(&new_rt->rt_uncached); 1673 1674 new_rt->dst.flags |= DST_HOST; 1675 new_rt->dst.input = rt->dst.input; 1676 new_rt->dst.output = rt->dst.output; 1677 new_rt->dst.error = rt->dst.error; 1678 new_rt->dst.lastuse = jiffies; 1679 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate); 1680 } 1681 return new_rt; 1682 } 1683 EXPORT_SYMBOL(rt_dst_clone); 1684 1685 /* called in rcu_read_lock() section */ 1686 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1687 u8 tos, struct net_device *dev, 1688 struct in_device *in_dev, u32 *itag) 1689 { 1690 int err; 1691 1692 /* Primary sanity checks. */ 1693 if (!in_dev) 1694 return -EINVAL; 1695 1696 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1697 skb->protocol != htons(ETH_P_IP)) 1698 return -EINVAL; 1699 1700 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1701 return -EINVAL; 1702 1703 if (ipv4_is_zeronet(saddr)) { 1704 if (!ipv4_is_local_multicast(daddr) && 1705 ip_hdr(skb)->protocol != IPPROTO_IGMP) 1706 return -EINVAL; 1707 } else { 1708 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1709 in_dev, itag); 1710 if (err < 0) 1711 return err; 1712 } 1713 return 0; 1714 } 1715 1716 /* called in rcu_read_lock() section */ 1717 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1718 u8 tos, struct net_device *dev, int our) 1719 { 1720 struct in_device *in_dev = __in_dev_get_rcu(dev); 1721 unsigned int flags = RTCF_MULTICAST; 1722 struct rtable *rth; 1723 u32 itag = 0; 1724 int err; 1725 1726 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag); 1727 if (err) 1728 return err; 1729 1730 if (our) 1731 flags |= RTCF_LOCAL; 1732 1733 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1734 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1735 if (!rth) 1736 return -ENOBUFS; 1737 1738 #ifdef CONFIG_IP_ROUTE_CLASSID 1739 rth->dst.tclassid = itag; 1740 #endif 1741 rth->dst.output = ip_rt_bug; 1742 rth->rt_is_input= 1; 1743 1744 #ifdef CONFIG_IP_MROUTE 1745 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1746 rth->dst.input = ip_mr_input; 1747 #endif 1748 RT_CACHE_STAT_INC(in_slow_mc); 1749 1750 skb_dst_set(skb, &rth->dst); 1751 return 0; 1752 } 1753 1754 1755 static void ip_handle_martian_source(struct net_device *dev, 1756 struct in_device *in_dev, 1757 struct sk_buff *skb, 1758 __be32 daddr, 1759 __be32 saddr) 1760 { 1761 RT_CACHE_STAT_INC(in_martian_src); 1762 #ifdef CONFIG_IP_ROUTE_VERBOSE 1763 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1764 /* 1765 * RFC1812 recommendation, if source is martian, 1766 * the only hint is MAC header. 1767 */ 1768 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1769 &daddr, &saddr, dev->name); 1770 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1771 print_hex_dump(KERN_WARNING, "ll header: ", 1772 DUMP_PREFIX_OFFSET, 16, 1, 1773 skb_mac_header(skb), 1774 dev->hard_header_len, false); 1775 } 1776 } 1777 #endif 1778 } 1779 1780 /* called in rcu_read_lock() section */ 1781 static int __mkroute_input(struct sk_buff *skb, 1782 const struct fib_result *res, 1783 struct in_device *in_dev, 1784 __be32 daddr, __be32 saddr, u32 tos) 1785 { 1786 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 1787 struct net_device *dev = nhc->nhc_dev; 1788 struct fib_nh_exception *fnhe; 1789 struct rtable *rth; 1790 int err; 1791 struct in_device *out_dev; 1792 bool do_cache; 1793 u32 itag = 0; 1794 1795 /* get a working reference to the output device */ 1796 out_dev = __in_dev_get_rcu(dev); 1797 if (!out_dev) { 1798 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1799 return -EINVAL; 1800 } 1801 1802 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1803 in_dev->dev, in_dev, &itag); 1804 if (err < 0) { 1805 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1806 saddr); 1807 1808 goto cleanup; 1809 } 1810 1811 do_cache = res->fi && !itag; 1812 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1813 skb->protocol == htons(ETH_P_IP)) { 1814 __be32 gw; 1815 1816 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0; 1817 if (IN_DEV_SHARED_MEDIA(out_dev) || 1818 inet_addr_onlink(out_dev, saddr, gw)) 1819 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1820 } 1821 1822 if (skb->protocol != htons(ETH_P_IP)) { 1823 /* Not IP (i.e. ARP). Do not create route, if it is 1824 * invalid for proxy arp. DNAT routes are always valid. 1825 * 1826 * Proxy arp feature have been extended to allow, ARP 1827 * replies back to the same interface, to support 1828 * Private VLAN switch technologies. See arp.c. 1829 */ 1830 if (out_dev == in_dev && 1831 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1832 err = -EINVAL; 1833 goto cleanup; 1834 } 1835 } 1836 1837 fnhe = find_exception(nhc, daddr); 1838 if (do_cache) { 1839 if (fnhe) 1840 rth = rcu_dereference(fnhe->fnhe_rth_input); 1841 else 1842 rth = rcu_dereference(nhc->nhc_rth_input); 1843 if (rt_cache_valid(rth)) { 1844 skb_dst_set_noref(skb, &rth->dst); 1845 goto out; 1846 } 1847 } 1848 1849 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1850 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1851 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1852 if (!rth) { 1853 err = -ENOBUFS; 1854 goto cleanup; 1855 } 1856 1857 rth->rt_is_input = 1; 1858 RT_CACHE_STAT_INC(in_slow_tot); 1859 1860 rth->dst.input = ip_forward; 1861 1862 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag, 1863 do_cache); 1864 lwtunnel_set_redirect(&rth->dst); 1865 skb_dst_set(skb, &rth->dst); 1866 out: 1867 err = 0; 1868 cleanup: 1869 return err; 1870 } 1871 1872 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1873 /* To make ICMP packets follow the right flow, the multipath hash is 1874 * calculated from the inner IP addresses. 1875 */ 1876 static void ip_multipath_l3_keys(const struct sk_buff *skb, 1877 struct flow_keys *hash_keys) 1878 { 1879 const struct iphdr *outer_iph = ip_hdr(skb); 1880 const struct iphdr *key_iph = outer_iph; 1881 const struct iphdr *inner_iph; 1882 const struct icmphdr *icmph; 1883 struct iphdr _inner_iph; 1884 struct icmphdr _icmph; 1885 1886 if (likely(outer_iph->protocol != IPPROTO_ICMP)) 1887 goto out; 1888 1889 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1890 goto out; 1891 1892 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1893 &_icmph); 1894 if (!icmph) 1895 goto out; 1896 1897 if (!icmp_is_err(icmph->type)) 1898 goto out; 1899 1900 inner_iph = skb_header_pointer(skb, 1901 outer_iph->ihl * 4 + sizeof(_icmph), 1902 sizeof(_inner_iph), &_inner_iph); 1903 if (!inner_iph) 1904 goto out; 1905 1906 key_iph = inner_iph; 1907 out: 1908 hash_keys->addrs.v4addrs.src = key_iph->saddr; 1909 hash_keys->addrs.v4addrs.dst = key_iph->daddr; 1910 } 1911 1912 /* if skb is set it will be used and fl4 can be NULL */ 1913 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, 1914 const struct sk_buff *skb, struct flow_keys *flkeys) 1915 { 1916 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0; 1917 struct flow_keys hash_keys; 1918 u32 mhash; 1919 1920 switch (net->ipv4.sysctl_fib_multipath_hash_policy) { 1921 case 0: 1922 memset(&hash_keys, 0, sizeof(hash_keys)); 1923 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1924 if (skb) { 1925 ip_multipath_l3_keys(skb, &hash_keys); 1926 } else { 1927 hash_keys.addrs.v4addrs.src = fl4->saddr; 1928 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1929 } 1930 break; 1931 case 1: 1932 /* skb is currently provided only when forwarding */ 1933 if (skb) { 1934 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 1935 struct flow_keys keys; 1936 1937 /* short-circuit if we already have L4 hash present */ 1938 if (skb->l4_hash) 1939 return skb_get_hash_raw(skb) >> 1; 1940 1941 memset(&hash_keys, 0, sizeof(hash_keys)); 1942 1943 if (!flkeys) { 1944 skb_flow_dissect_flow_keys(skb, &keys, flag); 1945 flkeys = &keys; 1946 } 1947 1948 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1949 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src; 1950 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst; 1951 hash_keys.ports.src = flkeys->ports.src; 1952 hash_keys.ports.dst = flkeys->ports.dst; 1953 hash_keys.basic.ip_proto = flkeys->basic.ip_proto; 1954 } else { 1955 memset(&hash_keys, 0, sizeof(hash_keys)); 1956 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1957 hash_keys.addrs.v4addrs.src = fl4->saddr; 1958 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1959 hash_keys.ports.src = fl4->fl4_sport; 1960 hash_keys.ports.dst = fl4->fl4_dport; 1961 hash_keys.basic.ip_proto = fl4->flowi4_proto; 1962 } 1963 break; 1964 case 2: 1965 memset(&hash_keys, 0, sizeof(hash_keys)); 1966 /* skb is currently provided only when forwarding */ 1967 if (skb) { 1968 struct flow_keys keys; 1969 1970 skb_flow_dissect_flow_keys(skb, &keys, 0); 1971 /* Inner can be v4 or v6 */ 1972 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) { 1973 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1974 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src; 1975 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst; 1976 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) { 1977 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1978 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src; 1979 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst; 1980 hash_keys.tags.flow_label = keys.tags.flow_label; 1981 hash_keys.basic.ip_proto = keys.basic.ip_proto; 1982 } else { 1983 /* Same as case 0 */ 1984 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1985 ip_multipath_l3_keys(skb, &hash_keys); 1986 } 1987 } else { 1988 /* Same as case 0 */ 1989 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1990 hash_keys.addrs.v4addrs.src = fl4->saddr; 1991 hash_keys.addrs.v4addrs.dst = fl4->daddr; 1992 } 1993 break; 1994 } 1995 mhash = flow_hash_from_keys(&hash_keys); 1996 1997 if (multipath_hash) 1998 mhash = jhash_2words(mhash, multipath_hash, 0); 1999 2000 return mhash >> 1; 2001 } 2002 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 2003 2004 static int ip_mkroute_input(struct sk_buff *skb, 2005 struct fib_result *res, 2006 struct in_device *in_dev, 2007 __be32 daddr, __be32 saddr, u32 tos, 2008 struct flow_keys *hkeys) 2009 { 2010 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2011 if (res->fi && fib_info_num_path(res->fi) > 1) { 2012 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys); 2013 2014 fib_select_multipath(res, h); 2015 } 2016 #endif 2017 2018 /* create a routing cache entry */ 2019 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 2020 } 2021 2022 /* Implements all the saddr-related checks as ip_route_input_slow(), 2023 * assuming daddr is valid and the destination is not a local broadcast one. 2024 * Uses the provided hint instead of performing a route lookup. 2025 */ 2026 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2027 u8 tos, struct net_device *dev, 2028 const struct sk_buff *hint) 2029 { 2030 struct in_device *in_dev = __in_dev_get_rcu(dev); 2031 struct rtable *rt = (struct rtable *)hint; 2032 struct net *net = dev_net(dev); 2033 int err = -EINVAL; 2034 u32 tag = 0; 2035 2036 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2037 goto martian_source; 2038 2039 if (ipv4_is_zeronet(saddr)) 2040 goto martian_source; 2041 2042 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2043 goto martian_source; 2044 2045 if (rt->rt_type != RTN_LOCAL) 2046 goto skip_validate_source; 2047 2048 tos &= IPTOS_RT_MASK; 2049 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag); 2050 if (err < 0) 2051 goto martian_source; 2052 2053 skip_validate_source: 2054 skb_dst_copy(skb, hint); 2055 return 0; 2056 2057 martian_source: 2058 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2059 return err; 2060 } 2061 2062 /* 2063 * NOTE. We drop all the packets that has local source 2064 * addresses, because every properly looped back packet 2065 * must have correct destination already attached by output routine. 2066 * Changes in the enforced policies must be applied also to 2067 * ip_route_use_hint(). 2068 * 2069 * Such approach solves two big problems: 2070 * 1. Not simplex devices are handled properly. 2071 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2072 * called with rcu_read_lock() 2073 */ 2074 2075 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2076 u8 tos, struct net_device *dev, 2077 struct fib_result *res) 2078 { 2079 struct in_device *in_dev = __in_dev_get_rcu(dev); 2080 struct flow_keys *flkeys = NULL, _flkeys; 2081 struct net *net = dev_net(dev); 2082 struct ip_tunnel_info *tun_info; 2083 int err = -EINVAL; 2084 unsigned int flags = 0; 2085 u32 itag = 0; 2086 struct rtable *rth; 2087 struct flowi4 fl4; 2088 bool do_cache = true; 2089 2090 /* IP on this device is disabled. */ 2091 2092 if (!in_dev) 2093 goto out; 2094 2095 /* Check for the most weird martians, which can be not detected 2096 by fib_lookup. 2097 */ 2098 2099 tun_info = skb_tunnel_info(skb); 2100 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 2101 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 2102 else 2103 fl4.flowi4_tun_key.tun_id = 0; 2104 skb_dst_drop(skb); 2105 2106 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 2107 goto martian_source; 2108 2109 res->fi = NULL; 2110 res->table = NULL; 2111 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2112 goto brd_input; 2113 2114 /* Accept zero addresses only to limited broadcast; 2115 * I even do not know to fix it or not. Waiting for complains :-) 2116 */ 2117 if (ipv4_is_zeronet(saddr)) 2118 goto martian_source; 2119 2120 if (ipv4_is_zeronet(daddr)) 2121 goto martian_destination; 2122 2123 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 2124 * and call it once if daddr or/and saddr are loopback addresses 2125 */ 2126 if (ipv4_is_loopback(daddr)) { 2127 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2128 goto martian_destination; 2129 } else if (ipv4_is_loopback(saddr)) { 2130 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 2131 goto martian_source; 2132 } 2133 2134 /* 2135 * Now we are ready to route packet. 2136 */ 2137 fl4.flowi4_oif = 0; 2138 fl4.flowi4_iif = dev->ifindex; 2139 fl4.flowi4_mark = skb->mark; 2140 fl4.flowi4_tos = tos; 2141 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2142 fl4.flowi4_flags = 0; 2143 fl4.daddr = daddr; 2144 fl4.saddr = saddr; 2145 fl4.flowi4_uid = sock_net_uid(net, NULL); 2146 2147 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) { 2148 flkeys = &_flkeys; 2149 } else { 2150 fl4.flowi4_proto = 0; 2151 fl4.fl4_sport = 0; 2152 fl4.fl4_dport = 0; 2153 } 2154 2155 err = fib_lookup(net, &fl4, res, 0); 2156 if (err != 0) { 2157 if (!IN_DEV_FORWARD(in_dev)) 2158 err = -EHOSTUNREACH; 2159 goto no_route; 2160 } 2161 2162 if (res->type == RTN_BROADCAST) { 2163 if (IN_DEV_BFORWARD(in_dev)) 2164 goto make_route; 2165 /* not do cache if bc_forwarding is enabled */ 2166 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) 2167 do_cache = false; 2168 goto brd_input; 2169 } 2170 2171 if (res->type == RTN_LOCAL) { 2172 err = fib_validate_source(skb, saddr, daddr, tos, 2173 0, dev, in_dev, &itag); 2174 if (err < 0) 2175 goto martian_source; 2176 goto local_input; 2177 } 2178 2179 if (!IN_DEV_FORWARD(in_dev)) { 2180 err = -EHOSTUNREACH; 2181 goto no_route; 2182 } 2183 if (res->type != RTN_UNICAST) 2184 goto martian_destination; 2185 2186 make_route: 2187 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys); 2188 out: return err; 2189 2190 brd_input: 2191 if (skb->protocol != htons(ETH_P_IP)) 2192 goto e_inval; 2193 2194 if (!ipv4_is_zeronet(saddr)) { 2195 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 2196 in_dev, &itag); 2197 if (err < 0) 2198 goto martian_source; 2199 } 2200 flags |= RTCF_BROADCAST; 2201 res->type = RTN_BROADCAST; 2202 RT_CACHE_STAT_INC(in_brd); 2203 2204 local_input: 2205 do_cache &= res->fi && !itag; 2206 if (do_cache) { 2207 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2208 2209 rth = rcu_dereference(nhc->nhc_rth_input); 2210 if (rt_cache_valid(rth)) { 2211 skb_dst_set_noref(skb, &rth->dst); 2212 err = 0; 2213 goto out; 2214 } 2215 } 2216 2217 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, 2218 flags | RTCF_LOCAL, res->type, 2219 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 2220 if (!rth) 2221 goto e_nobufs; 2222 2223 rth->dst.output= ip_rt_bug; 2224 #ifdef CONFIG_IP_ROUTE_CLASSID 2225 rth->dst.tclassid = itag; 2226 #endif 2227 rth->rt_is_input = 1; 2228 2229 RT_CACHE_STAT_INC(in_slow_tot); 2230 if (res->type == RTN_UNREACHABLE) { 2231 rth->dst.input= ip_error; 2232 rth->dst.error= -err; 2233 rth->rt_flags &= ~RTCF_LOCAL; 2234 } 2235 2236 if (do_cache) { 2237 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2238 2239 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate); 2240 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 2241 WARN_ON(rth->dst.input == lwtunnel_input); 2242 rth->dst.lwtstate->orig_input = rth->dst.input; 2243 rth->dst.input = lwtunnel_input; 2244 } 2245 2246 if (unlikely(!rt_cache_route(nhc, rth))) 2247 rt_add_uncached_list(rth); 2248 } 2249 skb_dst_set(skb, &rth->dst); 2250 err = 0; 2251 goto out; 2252 2253 no_route: 2254 RT_CACHE_STAT_INC(in_no_route); 2255 res->type = RTN_UNREACHABLE; 2256 res->fi = NULL; 2257 res->table = NULL; 2258 goto local_input; 2259 2260 /* 2261 * Do not cache martian addresses: they should be logged (RFC1812) 2262 */ 2263 martian_destination: 2264 RT_CACHE_STAT_INC(in_martian_dst); 2265 #ifdef CONFIG_IP_ROUTE_VERBOSE 2266 if (IN_DEV_LOG_MARTIANS(in_dev)) 2267 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2268 &daddr, &saddr, dev->name); 2269 #endif 2270 2271 e_inval: 2272 err = -EINVAL; 2273 goto out; 2274 2275 e_nobufs: 2276 err = -ENOBUFS; 2277 goto out; 2278 2279 martian_source: 2280 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2281 goto out; 2282 } 2283 2284 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2285 u8 tos, struct net_device *dev) 2286 { 2287 struct fib_result res; 2288 int err; 2289 2290 tos &= IPTOS_RT_MASK; 2291 rcu_read_lock(); 2292 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res); 2293 rcu_read_unlock(); 2294 2295 return err; 2296 } 2297 EXPORT_SYMBOL(ip_route_input_noref); 2298 2299 /* called with rcu_read_lock held */ 2300 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2301 u8 tos, struct net_device *dev, struct fib_result *res) 2302 { 2303 /* Multicast recognition logic is moved from route cache to here. 2304 The problem was that too many Ethernet cards have broken/missing 2305 hardware multicast filters :-( As result the host on multicasting 2306 network acquires a lot of useless route cache entries, sort of 2307 SDR messages from all the world. Now we try to get rid of them. 2308 Really, provided software IP multicast filter is organized 2309 reasonably (at least, hashed), it does not result in a slowdown 2310 comparing with route cache reject entries. 2311 Note, that multicast routers are not affected, because 2312 route cache entry is created eventually. 2313 */ 2314 if (ipv4_is_multicast(daddr)) { 2315 struct in_device *in_dev = __in_dev_get_rcu(dev); 2316 int our = 0; 2317 int err = -EINVAL; 2318 2319 if (!in_dev) 2320 return err; 2321 our = ip_check_mc_rcu(in_dev, daddr, saddr, 2322 ip_hdr(skb)->protocol); 2323 2324 /* check l3 master if no match yet */ 2325 if (!our && netif_is_l3_slave(dev)) { 2326 struct in_device *l3_in_dev; 2327 2328 l3_in_dev = __in_dev_get_rcu(skb->dev); 2329 if (l3_in_dev) 2330 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr, 2331 ip_hdr(skb)->protocol); 2332 } 2333 2334 if (our 2335 #ifdef CONFIG_IP_MROUTE 2336 || 2337 (!ipv4_is_local_multicast(daddr) && 2338 IN_DEV_MFORWARD(in_dev)) 2339 #endif 2340 ) { 2341 err = ip_route_input_mc(skb, daddr, saddr, 2342 tos, dev, our); 2343 } 2344 return err; 2345 } 2346 2347 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res); 2348 } 2349 2350 /* called with rcu_read_lock() */ 2351 static struct rtable *__mkroute_output(const struct fib_result *res, 2352 const struct flowi4 *fl4, int orig_oif, 2353 struct net_device *dev_out, 2354 unsigned int flags) 2355 { 2356 struct fib_info *fi = res->fi; 2357 struct fib_nh_exception *fnhe; 2358 struct in_device *in_dev; 2359 u16 type = res->type; 2360 struct rtable *rth; 2361 bool do_cache; 2362 2363 in_dev = __in_dev_get_rcu(dev_out); 2364 if (!in_dev) 2365 return ERR_PTR(-EINVAL); 2366 2367 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2368 if (ipv4_is_loopback(fl4->saddr) && 2369 !(dev_out->flags & IFF_LOOPBACK) && 2370 !netif_is_l3_master(dev_out)) 2371 return ERR_PTR(-EINVAL); 2372 2373 if (ipv4_is_lbcast(fl4->daddr)) 2374 type = RTN_BROADCAST; 2375 else if (ipv4_is_multicast(fl4->daddr)) 2376 type = RTN_MULTICAST; 2377 else if (ipv4_is_zeronet(fl4->daddr)) 2378 return ERR_PTR(-EINVAL); 2379 2380 if (dev_out->flags & IFF_LOOPBACK) 2381 flags |= RTCF_LOCAL; 2382 2383 do_cache = true; 2384 if (type == RTN_BROADCAST) { 2385 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2386 fi = NULL; 2387 } else if (type == RTN_MULTICAST) { 2388 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2389 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2390 fl4->flowi4_proto)) 2391 flags &= ~RTCF_LOCAL; 2392 else 2393 do_cache = false; 2394 /* If multicast route do not exist use 2395 * default one, but do not gateway in this case. 2396 * Yes, it is hack. 2397 */ 2398 if (fi && res->prefixlen < 4) 2399 fi = NULL; 2400 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2401 (orig_oif != dev_out->ifindex)) { 2402 /* For local routes that require a particular output interface 2403 * we do not want to cache the result. Caching the result 2404 * causes incorrect behaviour when there are multiple source 2405 * addresses on the interface, the end result being that if the 2406 * intended recipient is waiting on that interface for the 2407 * packet he won't receive it because it will be delivered on 2408 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2409 * be set to the loopback interface as well. 2410 */ 2411 do_cache = false; 2412 } 2413 2414 fnhe = NULL; 2415 do_cache &= fi != NULL; 2416 if (fi) { 2417 struct fib_nh_common *nhc = FIB_RES_NHC(*res); 2418 struct rtable __rcu **prth; 2419 2420 fnhe = find_exception(nhc, fl4->daddr); 2421 if (!do_cache) 2422 goto add; 2423 if (fnhe) { 2424 prth = &fnhe->fnhe_rth_output; 2425 } else { 2426 if (unlikely(fl4->flowi4_flags & 2427 FLOWI_FLAG_KNOWN_NH && 2428 !(nhc->nhc_gw_family && 2429 nhc->nhc_scope == RT_SCOPE_LINK))) { 2430 do_cache = false; 2431 goto add; 2432 } 2433 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output); 2434 } 2435 rth = rcu_dereference(*prth); 2436 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst)) 2437 return rth; 2438 } 2439 2440 add: 2441 rth = rt_dst_alloc(dev_out, flags, type, 2442 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2443 IN_DEV_CONF_GET(in_dev, NOXFRM), 2444 do_cache); 2445 if (!rth) 2446 return ERR_PTR(-ENOBUFS); 2447 2448 rth->rt_iif = orig_oif; 2449 2450 RT_CACHE_STAT_INC(out_slow_tot); 2451 2452 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2453 if (flags & RTCF_LOCAL && 2454 !(dev_out->flags & IFF_LOOPBACK)) { 2455 rth->dst.output = ip_mc_output; 2456 RT_CACHE_STAT_INC(out_slow_mc); 2457 } 2458 #ifdef CONFIG_IP_MROUTE 2459 if (type == RTN_MULTICAST) { 2460 if (IN_DEV_MFORWARD(in_dev) && 2461 !ipv4_is_local_multicast(fl4->daddr)) { 2462 rth->dst.input = ip_mr_input; 2463 rth->dst.output = ip_mc_output; 2464 } 2465 } 2466 #endif 2467 } 2468 2469 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache); 2470 lwtunnel_set_redirect(&rth->dst); 2471 2472 return rth; 2473 } 2474 2475 /* 2476 * Major route resolver routine. 2477 */ 2478 2479 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2480 const struct sk_buff *skb) 2481 { 2482 __u8 tos = RT_FL_TOS(fl4); 2483 struct fib_result res = { 2484 .type = RTN_UNSPEC, 2485 .fi = NULL, 2486 .table = NULL, 2487 .tclassid = 0, 2488 }; 2489 struct rtable *rth; 2490 2491 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2492 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2493 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2494 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2495 2496 rcu_read_lock(); 2497 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb); 2498 rcu_read_unlock(); 2499 2500 return rth; 2501 } 2502 EXPORT_SYMBOL_GPL(ip_route_output_key_hash); 2503 2504 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4, 2505 struct fib_result *res, 2506 const struct sk_buff *skb) 2507 { 2508 struct net_device *dev_out = NULL; 2509 int orig_oif = fl4->flowi4_oif; 2510 unsigned int flags = 0; 2511 struct rtable *rth; 2512 int err; 2513 2514 if (fl4->saddr) { 2515 if (ipv4_is_multicast(fl4->saddr) || 2516 ipv4_is_lbcast(fl4->saddr) || 2517 ipv4_is_zeronet(fl4->saddr)) { 2518 rth = ERR_PTR(-EINVAL); 2519 goto out; 2520 } 2521 2522 rth = ERR_PTR(-ENETUNREACH); 2523 2524 /* I removed check for oif == dev_out->oif here. 2525 It was wrong for two reasons: 2526 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2527 is assigned to multiple interfaces. 2528 2. Moreover, we are allowed to send packets with saddr 2529 of another iface. --ANK 2530 */ 2531 2532 if (fl4->flowi4_oif == 0 && 2533 (ipv4_is_multicast(fl4->daddr) || 2534 ipv4_is_lbcast(fl4->daddr))) { 2535 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2536 dev_out = __ip_dev_find(net, fl4->saddr, false); 2537 if (!dev_out) 2538 goto out; 2539 2540 /* Special hack: user can direct multicasts 2541 and limited broadcast via necessary interface 2542 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2543 This hack is not just for fun, it allows 2544 vic,vat and friends to work. 2545 They bind socket to loopback, set ttl to zero 2546 and expect that it will work. 2547 From the viewpoint of routing cache they are broken, 2548 because we are not allowed to build multicast path 2549 with loopback source addr (look, routing cache 2550 cannot know, that ttl is zero, so that packet 2551 will not leave this host and route is valid). 2552 Luckily, this hack is good workaround. 2553 */ 2554 2555 fl4->flowi4_oif = dev_out->ifindex; 2556 goto make_route; 2557 } 2558 2559 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2560 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2561 if (!__ip_dev_find(net, fl4->saddr, false)) 2562 goto out; 2563 } 2564 } 2565 2566 2567 if (fl4->flowi4_oif) { 2568 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2569 rth = ERR_PTR(-ENODEV); 2570 if (!dev_out) 2571 goto out; 2572 2573 /* RACE: Check return value of inet_select_addr instead. */ 2574 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2575 rth = ERR_PTR(-ENETUNREACH); 2576 goto out; 2577 } 2578 if (ipv4_is_local_multicast(fl4->daddr) || 2579 ipv4_is_lbcast(fl4->daddr) || 2580 fl4->flowi4_proto == IPPROTO_IGMP) { 2581 if (!fl4->saddr) 2582 fl4->saddr = inet_select_addr(dev_out, 0, 2583 RT_SCOPE_LINK); 2584 goto make_route; 2585 } 2586 if (!fl4->saddr) { 2587 if (ipv4_is_multicast(fl4->daddr)) 2588 fl4->saddr = inet_select_addr(dev_out, 0, 2589 fl4->flowi4_scope); 2590 else if (!fl4->daddr) 2591 fl4->saddr = inet_select_addr(dev_out, 0, 2592 RT_SCOPE_HOST); 2593 } 2594 } 2595 2596 if (!fl4->daddr) { 2597 fl4->daddr = fl4->saddr; 2598 if (!fl4->daddr) 2599 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2600 dev_out = net->loopback_dev; 2601 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2602 res->type = RTN_LOCAL; 2603 flags |= RTCF_LOCAL; 2604 goto make_route; 2605 } 2606 2607 err = fib_lookup(net, fl4, res, 0); 2608 if (err) { 2609 res->fi = NULL; 2610 res->table = NULL; 2611 if (fl4->flowi4_oif && 2612 (ipv4_is_multicast(fl4->daddr) || 2613 !netif_index_is_l3_master(net, fl4->flowi4_oif))) { 2614 /* Apparently, routing tables are wrong. Assume, 2615 that the destination is on link. 2616 2617 WHY? DW. 2618 Because we are allowed to send to iface 2619 even if it has NO routes and NO assigned 2620 addresses. When oif is specified, routing 2621 tables are looked up with only one purpose: 2622 to catch if destination is gatewayed, rather than 2623 direct. Moreover, if MSG_DONTROUTE is set, 2624 we send packet, ignoring both routing tables 2625 and ifaddr state. --ANK 2626 2627 2628 We could make it even if oif is unknown, 2629 likely IPv6, but we do not. 2630 */ 2631 2632 if (fl4->saddr == 0) 2633 fl4->saddr = inet_select_addr(dev_out, 0, 2634 RT_SCOPE_LINK); 2635 res->type = RTN_UNICAST; 2636 goto make_route; 2637 } 2638 rth = ERR_PTR(err); 2639 goto out; 2640 } 2641 2642 if (res->type == RTN_LOCAL) { 2643 if (!fl4->saddr) { 2644 if (res->fi->fib_prefsrc) 2645 fl4->saddr = res->fi->fib_prefsrc; 2646 else 2647 fl4->saddr = fl4->daddr; 2648 } 2649 2650 /* L3 master device is the loopback for that domain */ 2651 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? : 2652 net->loopback_dev; 2653 2654 /* make sure orig_oif points to fib result device even 2655 * though packet rx/tx happens over loopback or l3mdev 2656 */ 2657 orig_oif = FIB_RES_OIF(*res); 2658 2659 fl4->flowi4_oif = dev_out->ifindex; 2660 flags |= RTCF_LOCAL; 2661 goto make_route; 2662 } 2663 2664 fib_select_path(net, res, fl4, skb); 2665 2666 dev_out = FIB_RES_DEV(*res); 2667 fl4->flowi4_oif = dev_out->ifindex; 2668 2669 2670 make_route: 2671 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags); 2672 2673 out: 2674 return rth; 2675 } 2676 2677 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2678 { 2679 return NULL; 2680 } 2681 2682 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2683 { 2684 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2685 2686 return mtu ? : dst->dev->mtu; 2687 } 2688 2689 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2690 struct sk_buff *skb, u32 mtu) 2691 { 2692 } 2693 2694 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2695 struct sk_buff *skb) 2696 { 2697 } 2698 2699 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2700 unsigned long old) 2701 { 2702 return NULL; 2703 } 2704 2705 static struct dst_ops ipv4_dst_blackhole_ops = { 2706 .family = AF_INET, 2707 .check = ipv4_blackhole_dst_check, 2708 .mtu = ipv4_blackhole_mtu, 2709 .default_advmss = ipv4_default_advmss, 2710 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2711 .redirect = ipv4_rt_blackhole_redirect, 2712 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2713 .neigh_lookup = ipv4_neigh_lookup, 2714 }; 2715 2716 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2717 { 2718 struct rtable *ort = (struct rtable *) dst_orig; 2719 struct rtable *rt; 2720 2721 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0); 2722 if (rt) { 2723 struct dst_entry *new = &rt->dst; 2724 2725 new->__use = 1; 2726 new->input = dst_discard; 2727 new->output = dst_discard_out; 2728 2729 new->dev = net->loopback_dev; 2730 if (new->dev) 2731 dev_hold(new->dev); 2732 2733 rt->rt_is_input = ort->rt_is_input; 2734 rt->rt_iif = ort->rt_iif; 2735 rt->rt_pmtu = ort->rt_pmtu; 2736 rt->rt_mtu_locked = ort->rt_mtu_locked; 2737 2738 rt->rt_genid = rt_genid_ipv4(net); 2739 rt->rt_flags = ort->rt_flags; 2740 rt->rt_type = ort->rt_type; 2741 rt->rt_uses_gateway = ort->rt_uses_gateway; 2742 rt->rt_gw_family = ort->rt_gw_family; 2743 if (rt->rt_gw_family == AF_INET) 2744 rt->rt_gw4 = ort->rt_gw4; 2745 else if (rt->rt_gw_family == AF_INET6) 2746 rt->rt_gw6 = ort->rt_gw6; 2747 2748 INIT_LIST_HEAD(&rt->rt_uncached); 2749 } 2750 2751 dst_release(dst_orig); 2752 2753 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2754 } 2755 2756 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2757 const struct sock *sk) 2758 { 2759 struct rtable *rt = __ip_route_output_key(net, flp4); 2760 2761 if (IS_ERR(rt)) 2762 return rt; 2763 2764 if (flp4->flowi4_proto) 2765 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2766 flowi4_to_flowi(flp4), 2767 sk, 0); 2768 2769 return rt; 2770 } 2771 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2772 2773 /* called with rcu_read_lock held */ 2774 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 2775 struct rtable *rt, u32 table_id, struct flowi4 *fl4, 2776 struct sk_buff *skb, u32 portid, u32 seq, 2777 unsigned int flags) 2778 { 2779 struct rtmsg *r; 2780 struct nlmsghdr *nlh; 2781 unsigned long expires = 0; 2782 u32 error; 2783 u32 metrics[RTAX_MAX]; 2784 2785 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags); 2786 if (!nlh) 2787 return -EMSGSIZE; 2788 2789 r = nlmsg_data(nlh); 2790 r->rtm_family = AF_INET; 2791 r->rtm_dst_len = 32; 2792 r->rtm_src_len = 0; 2793 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0; 2794 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT; 2795 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2796 goto nla_put_failure; 2797 r->rtm_type = rt->rt_type; 2798 r->rtm_scope = RT_SCOPE_UNIVERSE; 2799 r->rtm_protocol = RTPROT_UNSPEC; 2800 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2801 if (rt->rt_flags & RTCF_NOTIFY) 2802 r->rtm_flags |= RTM_F_NOTIFY; 2803 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2804 r->rtm_flags |= RTCF_DOREDIRECT; 2805 2806 if (nla_put_in_addr(skb, RTA_DST, dst)) 2807 goto nla_put_failure; 2808 if (src) { 2809 r->rtm_src_len = 32; 2810 if (nla_put_in_addr(skb, RTA_SRC, src)) 2811 goto nla_put_failure; 2812 } 2813 if (rt->dst.dev && 2814 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2815 goto nla_put_failure; 2816 #ifdef CONFIG_IP_ROUTE_CLASSID 2817 if (rt->dst.tclassid && 2818 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2819 goto nla_put_failure; 2820 #endif 2821 if (fl4 && !rt_is_input_route(rt) && 2822 fl4->saddr != src) { 2823 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2824 goto nla_put_failure; 2825 } 2826 if (rt->rt_uses_gateway) { 2827 if (rt->rt_gw_family == AF_INET && 2828 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) { 2829 goto nla_put_failure; 2830 } else if (rt->rt_gw_family == AF_INET6) { 2831 int alen = sizeof(struct in6_addr); 2832 struct nlattr *nla; 2833 struct rtvia *via; 2834 2835 nla = nla_reserve(skb, RTA_VIA, alen + 2); 2836 if (!nla) 2837 goto nla_put_failure; 2838 2839 via = nla_data(nla); 2840 via->rtvia_family = AF_INET6; 2841 memcpy(via->rtvia_addr, &rt->rt_gw6, alen); 2842 } 2843 } 2844 2845 expires = rt->dst.expires; 2846 if (expires) { 2847 unsigned long now = jiffies; 2848 2849 if (time_before(now, expires)) 2850 expires -= now; 2851 else 2852 expires = 0; 2853 } 2854 2855 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2856 if (rt->rt_pmtu && expires) 2857 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2858 if (rt->rt_mtu_locked && expires) 2859 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU); 2860 if (rtnetlink_put_metrics(skb, metrics) < 0) 2861 goto nla_put_failure; 2862 2863 if (fl4) { 2864 if (fl4->flowi4_mark && 2865 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2866 goto nla_put_failure; 2867 2868 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) && 2869 nla_put_u32(skb, RTA_UID, 2870 from_kuid_munged(current_user_ns(), 2871 fl4->flowi4_uid))) 2872 goto nla_put_failure; 2873 2874 if (rt_is_input_route(rt)) { 2875 #ifdef CONFIG_IP_MROUTE 2876 if (ipv4_is_multicast(dst) && 2877 !ipv4_is_local_multicast(dst) && 2878 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2879 int err = ipmr_get_route(net, skb, 2880 fl4->saddr, fl4->daddr, 2881 r, portid); 2882 2883 if (err <= 0) { 2884 if (err == 0) 2885 return 0; 2886 goto nla_put_failure; 2887 } 2888 } else 2889 #endif 2890 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif)) 2891 goto nla_put_failure; 2892 } 2893 } 2894 2895 error = rt->dst.error; 2896 2897 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2898 goto nla_put_failure; 2899 2900 nlmsg_end(skb, nlh); 2901 return 0; 2902 2903 nla_put_failure: 2904 nlmsg_cancel(skb, nlh); 2905 return -EMSGSIZE; 2906 } 2907 2908 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb, 2909 struct netlink_callback *cb, u32 table_id, 2910 struct fnhe_hash_bucket *bucket, int genid, 2911 int *fa_index, int fa_start, unsigned int flags) 2912 { 2913 int i; 2914 2915 for (i = 0; i < FNHE_HASH_SIZE; i++) { 2916 struct fib_nh_exception *fnhe; 2917 2918 for (fnhe = rcu_dereference(bucket[i].chain); fnhe; 2919 fnhe = rcu_dereference(fnhe->fnhe_next)) { 2920 struct rtable *rt; 2921 int err; 2922 2923 if (*fa_index < fa_start) 2924 goto next; 2925 2926 if (fnhe->fnhe_genid != genid) 2927 goto next; 2928 2929 if (fnhe->fnhe_expires && 2930 time_after(jiffies, fnhe->fnhe_expires)) 2931 goto next; 2932 2933 rt = rcu_dereference(fnhe->fnhe_rth_input); 2934 if (!rt) 2935 rt = rcu_dereference(fnhe->fnhe_rth_output); 2936 if (!rt) 2937 goto next; 2938 2939 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt, 2940 table_id, NULL, skb, 2941 NETLINK_CB(cb->skb).portid, 2942 cb->nlh->nlmsg_seq, flags); 2943 if (err) 2944 return err; 2945 next: 2946 (*fa_index)++; 2947 } 2948 } 2949 2950 return 0; 2951 } 2952 2953 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 2954 u32 table_id, struct fib_info *fi, 2955 int *fa_index, int fa_start, unsigned int flags) 2956 { 2957 struct net *net = sock_net(cb->skb->sk); 2958 int nhsel, genid = fnhe_genid(net); 2959 2960 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) { 2961 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel); 2962 struct fnhe_hash_bucket *bucket; 2963 int err; 2964 2965 if (nhc->nhc_flags & RTNH_F_DEAD) 2966 continue; 2967 2968 rcu_read_lock(); 2969 bucket = rcu_dereference(nhc->nhc_exceptions); 2970 err = 0; 2971 if (bucket) 2972 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket, 2973 genid, fa_index, fa_start, 2974 flags); 2975 rcu_read_unlock(); 2976 if (err) 2977 return err; 2978 } 2979 2980 return 0; 2981 } 2982 2983 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, 2984 u8 ip_proto, __be16 sport, 2985 __be16 dport) 2986 { 2987 struct sk_buff *skb; 2988 struct iphdr *iph; 2989 2990 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2991 if (!skb) 2992 return NULL; 2993 2994 /* Reserve room for dummy headers, this skb can pass 2995 * through good chunk of routing engine. 2996 */ 2997 skb_reset_mac_header(skb); 2998 skb_reset_network_header(skb); 2999 skb->protocol = htons(ETH_P_IP); 3000 iph = skb_put(skb, sizeof(struct iphdr)); 3001 iph->protocol = ip_proto; 3002 iph->saddr = src; 3003 iph->daddr = dst; 3004 iph->version = 0x4; 3005 iph->frag_off = 0; 3006 iph->ihl = 0x5; 3007 skb_set_transport_header(skb, skb->len); 3008 3009 switch (iph->protocol) { 3010 case IPPROTO_UDP: { 3011 struct udphdr *udph; 3012 3013 udph = skb_put_zero(skb, sizeof(struct udphdr)); 3014 udph->source = sport; 3015 udph->dest = dport; 3016 udph->len = sizeof(struct udphdr); 3017 udph->check = 0; 3018 break; 3019 } 3020 case IPPROTO_TCP: { 3021 struct tcphdr *tcph; 3022 3023 tcph = skb_put_zero(skb, sizeof(struct tcphdr)); 3024 tcph->source = sport; 3025 tcph->dest = dport; 3026 tcph->doff = sizeof(struct tcphdr) / 4; 3027 tcph->rst = 1; 3028 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), 3029 src, dst, 0); 3030 break; 3031 } 3032 case IPPROTO_ICMP: { 3033 struct icmphdr *icmph; 3034 3035 icmph = skb_put_zero(skb, sizeof(struct icmphdr)); 3036 icmph->type = ICMP_ECHO; 3037 icmph->code = 0; 3038 } 3039 } 3040 3041 return skb; 3042 } 3043 3044 static int inet_rtm_valid_getroute_req(struct sk_buff *skb, 3045 const struct nlmsghdr *nlh, 3046 struct nlattr **tb, 3047 struct netlink_ext_ack *extack) 3048 { 3049 struct rtmsg *rtm; 3050 int i, err; 3051 3052 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { 3053 NL_SET_ERR_MSG(extack, 3054 "ipv4: Invalid header for route get request"); 3055 return -EINVAL; 3056 } 3057 3058 if (!netlink_strict_get_check(skb)) 3059 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX, 3060 rtm_ipv4_policy, extack); 3061 3062 rtm = nlmsg_data(nlh); 3063 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || 3064 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || 3065 rtm->rtm_table || rtm->rtm_protocol || 3066 rtm->rtm_scope || rtm->rtm_type) { 3067 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); 3068 return -EINVAL; 3069 } 3070 3071 if (rtm->rtm_flags & ~(RTM_F_NOTIFY | 3072 RTM_F_LOOKUP_TABLE | 3073 RTM_F_FIB_MATCH)) { 3074 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); 3075 return -EINVAL; 3076 } 3077 3078 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX, 3079 rtm_ipv4_policy, extack); 3080 if (err) 3081 return err; 3082 3083 if ((tb[RTA_SRC] && !rtm->rtm_src_len) || 3084 (tb[RTA_DST] && !rtm->rtm_dst_len)) { 3085 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); 3086 return -EINVAL; 3087 } 3088 3089 for (i = 0; i <= RTA_MAX; i++) { 3090 if (!tb[i]) 3091 continue; 3092 3093 switch (i) { 3094 case RTA_IIF: 3095 case RTA_OIF: 3096 case RTA_SRC: 3097 case RTA_DST: 3098 case RTA_IP_PROTO: 3099 case RTA_SPORT: 3100 case RTA_DPORT: 3101 case RTA_MARK: 3102 case RTA_UID: 3103 break; 3104 default: 3105 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); 3106 return -EINVAL; 3107 } 3108 } 3109 3110 return 0; 3111 } 3112 3113 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 3114 struct netlink_ext_ack *extack) 3115 { 3116 struct net *net = sock_net(in_skb->sk); 3117 struct nlattr *tb[RTA_MAX+1]; 3118 u32 table_id = RT_TABLE_MAIN; 3119 __be16 sport = 0, dport = 0; 3120 struct fib_result res = {}; 3121 u8 ip_proto = IPPROTO_UDP; 3122 struct rtable *rt = NULL; 3123 struct sk_buff *skb; 3124 struct rtmsg *rtm; 3125 struct flowi4 fl4 = {}; 3126 __be32 dst = 0; 3127 __be32 src = 0; 3128 kuid_t uid; 3129 u32 iif; 3130 int err; 3131 int mark; 3132 3133 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); 3134 if (err < 0) 3135 return err; 3136 3137 rtm = nlmsg_data(nlh); 3138 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 3139 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 3140 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3141 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3142 if (tb[RTA_UID]) 3143 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID])); 3144 else 3145 uid = (iif ? INVALID_UID : current_uid()); 3146 3147 if (tb[RTA_IP_PROTO]) { 3148 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO], 3149 &ip_proto, AF_INET, extack); 3150 if (err) 3151 return err; 3152 } 3153 3154 if (tb[RTA_SPORT]) 3155 sport = nla_get_be16(tb[RTA_SPORT]); 3156 3157 if (tb[RTA_DPORT]) 3158 dport = nla_get_be16(tb[RTA_DPORT]); 3159 3160 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport); 3161 if (!skb) 3162 return -ENOBUFS; 3163 3164 fl4.daddr = dst; 3165 fl4.saddr = src; 3166 fl4.flowi4_tos = rtm->rtm_tos; 3167 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 3168 fl4.flowi4_mark = mark; 3169 fl4.flowi4_uid = uid; 3170 if (sport) 3171 fl4.fl4_sport = sport; 3172 if (dport) 3173 fl4.fl4_dport = dport; 3174 fl4.flowi4_proto = ip_proto; 3175 3176 rcu_read_lock(); 3177 3178 if (iif) { 3179 struct net_device *dev; 3180 3181 dev = dev_get_by_index_rcu(net, iif); 3182 if (!dev) { 3183 err = -ENODEV; 3184 goto errout_rcu; 3185 } 3186 3187 fl4.flowi4_iif = iif; /* for rt_fill_info */ 3188 skb->dev = dev; 3189 skb->mark = mark; 3190 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos, 3191 dev, &res); 3192 3193 rt = skb_rtable(skb); 3194 if (err == 0 && rt->dst.error) 3195 err = -rt->dst.error; 3196 } else { 3197 fl4.flowi4_iif = LOOPBACK_IFINDEX; 3198 skb->dev = net->loopback_dev; 3199 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb); 3200 err = 0; 3201 if (IS_ERR(rt)) 3202 err = PTR_ERR(rt); 3203 else 3204 skb_dst_set(skb, &rt->dst); 3205 } 3206 3207 if (err) 3208 goto errout_rcu; 3209 3210 if (rtm->rtm_flags & RTM_F_NOTIFY) 3211 rt->rt_flags |= RTCF_NOTIFY; 3212 3213 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 3214 table_id = res.table ? res.table->tb_id : 0; 3215 3216 /* reset skb for netlink reply msg */ 3217 skb_trim(skb, 0); 3218 skb_reset_network_header(skb); 3219 skb_reset_transport_header(skb); 3220 skb_reset_mac_header(skb); 3221 3222 if (rtm->rtm_flags & RTM_F_FIB_MATCH) { 3223 if (!res.fi) { 3224 err = fib_props[res.type].error; 3225 if (!err) 3226 err = -EHOSTUNREACH; 3227 goto errout_rcu; 3228 } 3229 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid, 3230 nlh->nlmsg_seq, RTM_NEWROUTE, table_id, 3231 rt->rt_type, res.prefix, res.prefixlen, 3232 fl4.flowi4_tos, res.fi, 0); 3233 } else { 3234 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb, 3235 NETLINK_CB(in_skb).portid, 3236 nlh->nlmsg_seq, 0); 3237 } 3238 if (err < 0) 3239 goto errout_rcu; 3240 3241 rcu_read_unlock(); 3242 3243 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 3244 3245 errout_free: 3246 return err; 3247 errout_rcu: 3248 rcu_read_unlock(); 3249 kfree_skb(skb); 3250 goto errout_free; 3251 } 3252 3253 void ip_rt_multicast_event(struct in_device *in_dev) 3254 { 3255 rt_cache_flush(dev_net(in_dev->dev)); 3256 } 3257 3258 #ifdef CONFIG_SYSCTL 3259 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 3260 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 3261 static int ip_rt_gc_elasticity __read_mostly = 8; 3262 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU; 3263 3264 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 3265 void __user *buffer, 3266 size_t *lenp, loff_t *ppos) 3267 { 3268 struct net *net = (struct net *)__ctl->extra1; 3269 3270 if (write) { 3271 rt_cache_flush(net); 3272 fnhe_genid_bump(net); 3273 return 0; 3274 } 3275 3276 return -EINVAL; 3277 } 3278 3279 static struct ctl_table ipv4_route_table[] = { 3280 { 3281 .procname = "gc_thresh", 3282 .data = &ipv4_dst_ops.gc_thresh, 3283 .maxlen = sizeof(int), 3284 .mode = 0644, 3285 .proc_handler = proc_dointvec, 3286 }, 3287 { 3288 .procname = "max_size", 3289 .data = &ip_rt_max_size, 3290 .maxlen = sizeof(int), 3291 .mode = 0644, 3292 .proc_handler = proc_dointvec, 3293 }, 3294 { 3295 /* Deprecated. Use gc_min_interval_ms */ 3296 3297 .procname = "gc_min_interval", 3298 .data = &ip_rt_gc_min_interval, 3299 .maxlen = sizeof(int), 3300 .mode = 0644, 3301 .proc_handler = proc_dointvec_jiffies, 3302 }, 3303 { 3304 .procname = "gc_min_interval_ms", 3305 .data = &ip_rt_gc_min_interval, 3306 .maxlen = sizeof(int), 3307 .mode = 0644, 3308 .proc_handler = proc_dointvec_ms_jiffies, 3309 }, 3310 { 3311 .procname = "gc_timeout", 3312 .data = &ip_rt_gc_timeout, 3313 .maxlen = sizeof(int), 3314 .mode = 0644, 3315 .proc_handler = proc_dointvec_jiffies, 3316 }, 3317 { 3318 .procname = "gc_interval", 3319 .data = &ip_rt_gc_interval, 3320 .maxlen = sizeof(int), 3321 .mode = 0644, 3322 .proc_handler = proc_dointvec_jiffies, 3323 }, 3324 { 3325 .procname = "redirect_load", 3326 .data = &ip_rt_redirect_load, 3327 .maxlen = sizeof(int), 3328 .mode = 0644, 3329 .proc_handler = proc_dointvec, 3330 }, 3331 { 3332 .procname = "redirect_number", 3333 .data = &ip_rt_redirect_number, 3334 .maxlen = sizeof(int), 3335 .mode = 0644, 3336 .proc_handler = proc_dointvec, 3337 }, 3338 { 3339 .procname = "redirect_silence", 3340 .data = &ip_rt_redirect_silence, 3341 .maxlen = sizeof(int), 3342 .mode = 0644, 3343 .proc_handler = proc_dointvec, 3344 }, 3345 { 3346 .procname = "error_cost", 3347 .data = &ip_rt_error_cost, 3348 .maxlen = sizeof(int), 3349 .mode = 0644, 3350 .proc_handler = proc_dointvec, 3351 }, 3352 { 3353 .procname = "error_burst", 3354 .data = &ip_rt_error_burst, 3355 .maxlen = sizeof(int), 3356 .mode = 0644, 3357 .proc_handler = proc_dointvec, 3358 }, 3359 { 3360 .procname = "gc_elasticity", 3361 .data = &ip_rt_gc_elasticity, 3362 .maxlen = sizeof(int), 3363 .mode = 0644, 3364 .proc_handler = proc_dointvec, 3365 }, 3366 { 3367 .procname = "mtu_expires", 3368 .data = &ip_rt_mtu_expires, 3369 .maxlen = sizeof(int), 3370 .mode = 0644, 3371 .proc_handler = proc_dointvec_jiffies, 3372 }, 3373 { 3374 .procname = "min_pmtu", 3375 .data = &ip_rt_min_pmtu, 3376 .maxlen = sizeof(int), 3377 .mode = 0644, 3378 .proc_handler = proc_dointvec_minmax, 3379 .extra1 = &ip_min_valid_pmtu, 3380 }, 3381 { 3382 .procname = "min_adv_mss", 3383 .data = &ip_rt_min_advmss, 3384 .maxlen = sizeof(int), 3385 .mode = 0644, 3386 .proc_handler = proc_dointvec, 3387 }, 3388 { } 3389 }; 3390 3391 static const char ipv4_route_flush_procname[] = "flush"; 3392 3393 static struct ctl_table ipv4_route_flush_table[] = { 3394 { 3395 .procname = ipv4_route_flush_procname, 3396 .maxlen = sizeof(int), 3397 .mode = 0200, 3398 .proc_handler = ipv4_sysctl_rtcache_flush, 3399 }, 3400 { }, 3401 }; 3402 3403 static __net_init int sysctl_route_net_init(struct net *net) 3404 { 3405 struct ctl_table *tbl; 3406 3407 tbl = ipv4_route_flush_table; 3408 if (!net_eq(net, &init_net)) { 3409 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3410 if (!tbl) 3411 goto err_dup; 3412 3413 /* Don't export non-whitelisted sysctls to unprivileged users */ 3414 if (net->user_ns != &init_user_ns) { 3415 if (tbl[0].procname != ipv4_route_flush_procname) 3416 tbl[0].procname = NULL; 3417 } 3418 } 3419 tbl[0].extra1 = net; 3420 3421 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3422 if (!net->ipv4.route_hdr) 3423 goto err_reg; 3424 return 0; 3425 3426 err_reg: 3427 if (tbl != ipv4_route_flush_table) 3428 kfree(tbl); 3429 err_dup: 3430 return -ENOMEM; 3431 } 3432 3433 static __net_exit void sysctl_route_net_exit(struct net *net) 3434 { 3435 struct ctl_table *tbl; 3436 3437 tbl = net->ipv4.route_hdr->ctl_table_arg; 3438 unregister_net_sysctl_table(net->ipv4.route_hdr); 3439 BUG_ON(tbl == ipv4_route_flush_table); 3440 kfree(tbl); 3441 } 3442 3443 static __net_initdata struct pernet_operations sysctl_route_ops = { 3444 .init = sysctl_route_net_init, 3445 .exit = sysctl_route_net_exit, 3446 }; 3447 #endif 3448 3449 static __net_init int rt_genid_init(struct net *net) 3450 { 3451 atomic_set(&net->ipv4.rt_genid, 0); 3452 atomic_set(&net->fnhe_genid, 0); 3453 atomic_set(&net->ipv4.dev_addr_genid, get_random_int()); 3454 return 0; 3455 } 3456 3457 static __net_initdata struct pernet_operations rt_genid_ops = { 3458 .init = rt_genid_init, 3459 }; 3460 3461 static int __net_init ipv4_inetpeer_init(struct net *net) 3462 { 3463 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 3464 3465 if (!bp) 3466 return -ENOMEM; 3467 inet_peer_base_init(bp); 3468 net->ipv4.peers = bp; 3469 return 0; 3470 } 3471 3472 static void __net_exit ipv4_inetpeer_exit(struct net *net) 3473 { 3474 struct inet_peer_base *bp = net->ipv4.peers; 3475 3476 net->ipv4.peers = NULL; 3477 inetpeer_invalidate_tree(bp); 3478 kfree(bp); 3479 } 3480 3481 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 3482 .init = ipv4_inetpeer_init, 3483 .exit = ipv4_inetpeer_exit, 3484 }; 3485 3486 #ifdef CONFIG_IP_ROUTE_CLASSID 3487 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3488 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3489 3490 int __init ip_rt_init(void) 3491 { 3492 int cpu; 3493 3494 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents), 3495 GFP_KERNEL); 3496 if (!ip_idents) 3497 panic("IP: failed to allocate ip_idents\n"); 3498 3499 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 3500 3501 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 3502 if (!ip_tstamps) 3503 panic("IP: failed to allocate ip_tstamps\n"); 3504 3505 for_each_possible_cpu(cpu) { 3506 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 3507 3508 INIT_LIST_HEAD(&ul->head); 3509 spin_lock_init(&ul->lock); 3510 } 3511 #ifdef CONFIG_IP_ROUTE_CLASSID 3512 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3513 if (!ip_rt_acct) 3514 panic("IP: failed to allocate ip_rt_acct\n"); 3515 #endif 3516 3517 ipv4_dst_ops.kmem_cachep = 3518 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3519 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3520 3521 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3522 3523 if (dst_entries_init(&ipv4_dst_ops) < 0) 3524 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3525 3526 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3527 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3528 3529 ipv4_dst_ops.gc_thresh = ~0; 3530 ip_rt_max_size = INT_MAX; 3531 3532 devinet_init(); 3533 ip_fib_init(); 3534 3535 if (ip_rt_proc_init()) 3536 pr_err("Unable to create route proc files\n"); 3537 #ifdef CONFIG_XFRM 3538 xfrm_init(); 3539 xfrm4_init(); 3540 #endif 3541 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, 3542 RTNL_FLAG_DOIT_UNLOCKED); 3543 3544 #ifdef CONFIG_SYSCTL 3545 register_pernet_subsys(&sysctl_route_ops); 3546 #endif 3547 register_pernet_subsys(&rt_genid_ops); 3548 register_pernet_subsys(&ipv4_inetpeer_ops); 3549 return 0; 3550 } 3551 3552 #ifdef CONFIG_SYSCTL 3553 /* 3554 * We really need to sanitize the damn ipv4 init order, then all 3555 * this nonsense will go away. 3556 */ 3557 void __init ip_static_sysctl_init(void) 3558 { 3559 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3560 } 3561 #endif 3562