1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * ROUTE - implementation of the IP router. 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Alan Cox, <gw4pts@gw4pts.ampr.org> 11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 13 * 14 * Fixes: 15 * Alan Cox : Verify area fixes. 16 * Alan Cox : cli() protects routing changes 17 * Rui Oliveira : ICMP routing table updates 18 * (rco@di.uminho.pt) Routing table insertion and update 19 * Linus Torvalds : Rewrote bits to be sensible 20 * Alan Cox : Added BSD route gw semantics 21 * Alan Cox : Super /proc >4K 22 * Alan Cox : MTU in route table 23 * Alan Cox : MSS actually. Also added the window 24 * clamper. 25 * Sam Lantinga : Fixed route matching in rt_del() 26 * Alan Cox : Routing cache support. 27 * Alan Cox : Removed compatibility cruft. 28 * Alan Cox : RTF_REJECT support. 29 * Alan Cox : TCP irtt support. 30 * Jonathan Naylor : Added Metric support. 31 * Miquel van Smoorenburg : BSD API fixes. 32 * Miquel van Smoorenburg : Metrics. 33 * Alan Cox : Use __u32 properly 34 * Alan Cox : Aligned routing errors more closely with BSD 35 * our system is still very different. 36 * Alan Cox : Faster /proc handling 37 * Alexey Kuznetsov : Massive rework to support tree based routing, 38 * routing caches and better behaviour. 39 * 40 * Olaf Erb : irtt wasn't being copied right. 41 * Bjorn Ekwall : Kerneld route support. 42 * Alan Cox : Multicast fixed (I hope) 43 * Pavel Krauz : Limited broadcast fixed 44 * Mike McLagan : Routing by source 45 * Alexey Kuznetsov : End of old history. Split to fib.c and 46 * route.c and rewritten from scratch. 47 * Andi Kleen : Load-limit warning messages. 48 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 52 * Marc Boucher : routing by fwmark 53 * Robert Olsson : Added rt_cache statistics 54 * Arnaldo C. Melo : Convert proc stuff to seq_file 55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 57 * Ilia Sotnikov : Removed TOS from hash calculations 58 * 59 * This program is free software; you can redistribute it and/or 60 * modify it under the terms of the GNU General Public License 61 * as published by the Free Software Foundation; either version 62 * 2 of the License, or (at your option) any later version. 63 */ 64 65 #define pr_fmt(fmt) "IPv4: " fmt 66 67 #include <linux/module.h> 68 #include <asm/uaccess.h> 69 #include <linux/bitops.h> 70 #include <linux/types.h> 71 #include <linux/kernel.h> 72 #include <linux/mm.h> 73 #include <linux/bootmem.h> 74 #include <linux/string.h> 75 #include <linux/socket.h> 76 #include <linux/sockios.h> 77 #include <linux/errno.h> 78 #include <linux/in.h> 79 #include <linux/inet.h> 80 #include <linux/netdevice.h> 81 #include <linux/proc_fs.h> 82 #include <linux/init.h> 83 #include <linux/workqueue.h> 84 #include <linux/skbuff.h> 85 #include <linux/inetdevice.h> 86 #include <linux/igmp.h> 87 #include <linux/pkt_sched.h> 88 #include <linux/mroute.h> 89 #include <linux/netfilter_ipv4.h> 90 #include <linux/random.h> 91 #include <linux/jhash.h> 92 #include <linux/rcupdate.h> 93 #include <linux/times.h> 94 #include <linux/slab.h> 95 #include <linux/prefetch.h> 96 #include <net/dst.h> 97 #include <net/net_namespace.h> 98 #include <net/protocol.h> 99 #include <net/ip.h> 100 #include <net/route.h> 101 #include <net/inetpeer.h> 102 #include <net/sock.h> 103 #include <net/ip_fib.h> 104 #include <net/arp.h> 105 #include <net/tcp.h> 106 #include <net/icmp.h> 107 #include <net/xfrm.h> 108 #include <net/netevent.h> 109 #include <net/rtnetlink.h> 110 #ifdef CONFIG_SYSCTL 111 #include <linux/sysctl.h> 112 #include <linux/kmemleak.h> 113 #endif 114 #include <net/secure_seq.h> 115 116 #define RT_FL_TOS(oldflp4) \ 117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 118 119 #define IP_MAX_MTU 0xFFF0 120 121 #define RT_GC_TIMEOUT (300*HZ) 122 123 static int ip_rt_max_size; 124 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 125 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 126 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 127 static int ip_rt_redirect_number __read_mostly = 9; 128 static int ip_rt_redirect_load __read_mostly = HZ / 50; 129 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 130 static int ip_rt_error_cost __read_mostly = HZ; 131 static int ip_rt_error_burst __read_mostly = 5 * HZ; 132 static int ip_rt_gc_elasticity __read_mostly = 8; 133 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 134 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 135 static int ip_rt_min_advmss __read_mostly = 256; 136 static int rt_chain_length_max __read_mostly = 20; 137 138 static struct delayed_work expires_work; 139 static unsigned long expires_ljiffies; 140 141 /* 142 * Interface to generic destination cache. 143 */ 144 145 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 146 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 147 static unsigned int ipv4_mtu(const struct dst_entry *dst); 148 static void ipv4_dst_destroy(struct dst_entry *dst); 149 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 150 static void ipv4_link_failure(struct sk_buff *skb); 151 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu); 152 static int rt_garbage_collect(struct dst_ops *ops); 153 154 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 155 int how) 156 { 157 } 158 159 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 160 { 161 struct rtable *rt = (struct rtable *) dst; 162 struct inet_peer *peer; 163 u32 *p = NULL; 164 165 if (!rt->peer) 166 rt_bind_peer(rt, rt->rt_dst, 1); 167 168 peer = rt->peer; 169 if (peer) { 170 u32 *old_p = __DST_METRICS_PTR(old); 171 unsigned long prev, new; 172 173 p = peer->metrics; 174 if (inet_metrics_new(peer)) 175 memcpy(p, old_p, sizeof(u32) * RTAX_MAX); 176 177 new = (unsigned long) p; 178 prev = cmpxchg(&dst->_metrics, old, new); 179 180 if (prev != old) { 181 p = __DST_METRICS_PTR(prev); 182 if (prev & DST_METRICS_READ_ONLY) 183 p = NULL; 184 } else { 185 if (rt->fi) { 186 fib_info_put(rt->fi); 187 rt->fi = NULL; 188 } 189 } 190 } 191 return p; 192 } 193 194 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr); 195 196 static struct dst_ops ipv4_dst_ops = { 197 .family = AF_INET, 198 .protocol = cpu_to_be16(ETH_P_IP), 199 .gc = rt_garbage_collect, 200 .check = ipv4_dst_check, 201 .default_advmss = ipv4_default_advmss, 202 .mtu = ipv4_mtu, 203 .cow_metrics = ipv4_cow_metrics, 204 .destroy = ipv4_dst_destroy, 205 .ifdown = ipv4_dst_ifdown, 206 .negative_advice = ipv4_negative_advice, 207 .link_failure = ipv4_link_failure, 208 .update_pmtu = ip_rt_update_pmtu, 209 .local_out = __ip_local_out, 210 .neigh_lookup = ipv4_neigh_lookup, 211 }; 212 213 #define ECN_OR_COST(class) TC_PRIO_##class 214 215 const __u8 ip_tos2prio[16] = { 216 TC_PRIO_BESTEFFORT, 217 ECN_OR_COST(BESTEFFORT), 218 TC_PRIO_BESTEFFORT, 219 ECN_OR_COST(BESTEFFORT), 220 TC_PRIO_BULK, 221 ECN_OR_COST(BULK), 222 TC_PRIO_BULK, 223 ECN_OR_COST(BULK), 224 TC_PRIO_INTERACTIVE, 225 ECN_OR_COST(INTERACTIVE), 226 TC_PRIO_INTERACTIVE, 227 ECN_OR_COST(INTERACTIVE), 228 TC_PRIO_INTERACTIVE_BULK, 229 ECN_OR_COST(INTERACTIVE_BULK), 230 TC_PRIO_INTERACTIVE_BULK, 231 ECN_OR_COST(INTERACTIVE_BULK) 232 }; 233 EXPORT_SYMBOL(ip_tos2prio); 234 235 /* 236 * Route cache. 237 */ 238 239 /* The locking scheme is rather straight forward: 240 * 241 * 1) Read-Copy Update protects the buckets of the central route hash. 242 * 2) Only writers remove entries, and they hold the lock 243 * as they look at rtable reference counts. 244 * 3) Only readers acquire references to rtable entries, 245 * they do so with atomic increments and with the 246 * lock held. 247 */ 248 249 struct rt_hash_bucket { 250 struct rtable __rcu *chain; 251 }; 252 253 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \ 254 defined(CONFIG_PROVE_LOCKING) 255 /* 256 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks 257 * The size of this table is a power of two and depends on the number of CPUS. 258 * (on lockdep we have a quite big spinlock_t, so keep the size down there) 259 */ 260 #ifdef CONFIG_LOCKDEP 261 # define RT_HASH_LOCK_SZ 256 262 #else 263 # if NR_CPUS >= 32 264 # define RT_HASH_LOCK_SZ 4096 265 # elif NR_CPUS >= 16 266 # define RT_HASH_LOCK_SZ 2048 267 # elif NR_CPUS >= 8 268 # define RT_HASH_LOCK_SZ 1024 269 # elif NR_CPUS >= 4 270 # define RT_HASH_LOCK_SZ 512 271 # else 272 # define RT_HASH_LOCK_SZ 256 273 # endif 274 #endif 275 276 static spinlock_t *rt_hash_locks; 277 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)] 278 279 static __init void rt_hash_lock_init(void) 280 { 281 int i; 282 283 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ, 284 GFP_KERNEL); 285 if (!rt_hash_locks) 286 panic("IP: failed to allocate rt_hash_locks\n"); 287 288 for (i = 0; i < RT_HASH_LOCK_SZ; i++) 289 spin_lock_init(&rt_hash_locks[i]); 290 } 291 #else 292 # define rt_hash_lock_addr(slot) NULL 293 294 static inline void rt_hash_lock_init(void) 295 { 296 } 297 #endif 298 299 static struct rt_hash_bucket *rt_hash_table __read_mostly; 300 static unsigned int rt_hash_mask __read_mostly; 301 static unsigned int rt_hash_log __read_mostly; 302 303 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 304 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field) 305 306 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx, 307 int genid) 308 { 309 return jhash_3words((__force u32)daddr, (__force u32)saddr, 310 idx, genid) 311 & rt_hash_mask; 312 } 313 314 static inline int rt_genid(struct net *net) 315 { 316 return atomic_read(&net->ipv4.rt_genid); 317 } 318 319 #ifdef CONFIG_PROC_FS 320 struct rt_cache_iter_state { 321 struct seq_net_private p; 322 int bucket; 323 int genid; 324 }; 325 326 static struct rtable *rt_cache_get_first(struct seq_file *seq) 327 { 328 struct rt_cache_iter_state *st = seq->private; 329 struct rtable *r = NULL; 330 331 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) { 332 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain)) 333 continue; 334 rcu_read_lock_bh(); 335 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain); 336 while (r) { 337 if (dev_net(r->dst.dev) == seq_file_net(seq) && 338 r->rt_genid == st->genid) 339 return r; 340 r = rcu_dereference_bh(r->dst.rt_next); 341 } 342 rcu_read_unlock_bh(); 343 } 344 return r; 345 } 346 347 static struct rtable *__rt_cache_get_next(struct seq_file *seq, 348 struct rtable *r) 349 { 350 struct rt_cache_iter_state *st = seq->private; 351 352 r = rcu_dereference_bh(r->dst.rt_next); 353 while (!r) { 354 rcu_read_unlock_bh(); 355 do { 356 if (--st->bucket < 0) 357 return NULL; 358 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain)); 359 rcu_read_lock_bh(); 360 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain); 361 } 362 return r; 363 } 364 365 static struct rtable *rt_cache_get_next(struct seq_file *seq, 366 struct rtable *r) 367 { 368 struct rt_cache_iter_state *st = seq->private; 369 while ((r = __rt_cache_get_next(seq, r)) != NULL) { 370 if (dev_net(r->dst.dev) != seq_file_net(seq)) 371 continue; 372 if (r->rt_genid == st->genid) 373 break; 374 } 375 return r; 376 } 377 378 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos) 379 { 380 struct rtable *r = rt_cache_get_first(seq); 381 382 if (r) 383 while (pos && (r = rt_cache_get_next(seq, r))) 384 --pos; 385 return pos ? NULL : r; 386 } 387 388 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 389 { 390 struct rt_cache_iter_state *st = seq->private; 391 if (*pos) 392 return rt_cache_get_idx(seq, *pos - 1); 393 st->genid = rt_genid(seq_file_net(seq)); 394 return SEQ_START_TOKEN; 395 } 396 397 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 398 { 399 struct rtable *r; 400 401 if (v == SEQ_START_TOKEN) 402 r = rt_cache_get_first(seq); 403 else 404 r = rt_cache_get_next(seq, v); 405 ++*pos; 406 return r; 407 } 408 409 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 410 { 411 if (v && v != SEQ_START_TOKEN) 412 rcu_read_unlock_bh(); 413 } 414 415 static int rt_cache_seq_show(struct seq_file *seq, void *v) 416 { 417 if (v == SEQ_START_TOKEN) 418 seq_printf(seq, "%-127s\n", 419 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 420 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 421 "HHUptod\tSpecDst"); 422 else { 423 struct rtable *r = v; 424 struct neighbour *n; 425 int len, HHUptod; 426 427 rcu_read_lock(); 428 n = dst_get_neighbour_noref(&r->dst); 429 HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0; 430 rcu_read_unlock(); 431 432 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t" 433 "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n", 434 r->dst.dev ? r->dst.dev->name : "*", 435 (__force u32)r->rt_dst, 436 (__force u32)r->rt_gateway, 437 r->rt_flags, atomic_read(&r->dst.__refcnt), 438 r->dst.__use, 0, (__force u32)r->rt_src, 439 dst_metric_advmss(&r->dst) + 40, 440 dst_metric(&r->dst, RTAX_WINDOW), 441 (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) + 442 dst_metric(&r->dst, RTAX_RTTVAR)), 443 r->rt_key_tos, 444 -1, 445 HHUptod, 446 r->rt_spec_dst, &len); 447 448 seq_printf(seq, "%*s\n", 127 - len, ""); 449 } 450 return 0; 451 } 452 453 static const struct seq_operations rt_cache_seq_ops = { 454 .start = rt_cache_seq_start, 455 .next = rt_cache_seq_next, 456 .stop = rt_cache_seq_stop, 457 .show = rt_cache_seq_show, 458 }; 459 460 static int rt_cache_seq_open(struct inode *inode, struct file *file) 461 { 462 return seq_open_net(inode, file, &rt_cache_seq_ops, 463 sizeof(struct rt_cache_iter_state)); 464 } 465 466 static const struct file_operations rt_cache_seq_fops = { 467 .owner = THIS_MODULE, 468 .open = rt_cache_seq_open, 469 .read = seq_read, 470 .llseek = seq_lseek, 471 .release = seq_release_net, 472 }; 473 474 475 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 476 { 477 int cpu; 478 479 if (*pos == 0) 480 return SEQ_START_TOKEN; 481 482 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 483 if (!cpu_possible(cpu)) 484 continue; 485 *pos = cpu+1; 486 return &per_cpu(rt_cache_stat, cpu); 487 } 488 return NULL; 489 } 490 491 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 492 { 493 int cpu; 494 495 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 496 if (!cpu_possible(cpu)) 497 continue; 498 *pos = cpu+1; 499 return &per_cpu(rt_cache_stat, cpu); 500 } 501 return NULL; 502 503 } 504 505 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 506 { 507 508 } 509 510 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 511 { 512 struct rt_cache_stat *st = v; 513 514 if (v == SEQ_START_TOKEN) { 515 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"); 516 return 0; 517 } 518 519 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 520 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 521 dst_entries_get_slow(&ipv4_dst_ops), 522 st->in_hit, 523 st->in_slow_tot, 524 st->in_slow_mc, 525 st->in_no_route, 526 st->in_brd, 527 st->in_martian_dst, 528 st->in_martian_src, 529 530 st->out_hit, 531 st->out_slow_tot, 532 st->out_slow_mc, 533 534 st->gc_total, 535 st->gc_ignored, 536 st->gc_goal_miss, 537 st->gc_dst_overflow, 538 st->in_hlist_search, 539 st->out_hlist_search 540 ); 541 return 0; 542 } 543 544 static const struct seq_operations rt_cpu_seq_ops = { 545 .start = rt_cpu_seq_start, 546 .next = rt_cpu_seq_next, 547 .stop = rt_cpu_seq_stop, 548 .show = rt_cpu_seq_show, 549 }; 550 551 552 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 553 { 554 return seq_open(file, &rt_cpu_seq_ops); 555 } 556 557 static const struct file_operations rt_cpu_seq_fops = { 558 .owner = THIS_MODULE, 559 .open = rt_cpu_seq_open, 560 .read = seq_read, 561 .llseek = seq_lseek, 562 .release = seq_release, 563 }; 564 565 #ifdef CONFIG_IP_ROUTE_CLASSID 566 static int rt_acct_proc_show(struct seq_file *m, void *v) 567 { 568 struct ip_rt_acct *dst, *src; 569 unsigned int i, j; 570 571 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 572 if (!dst) 573 return -ENOMEM; 574 575 for_each_possible_cpu(i) { 576 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 577 for (j = 0; j < 256; j++) { 578 dst[j].o_bytes += src[j].o_bytes; 579 dst[j].o_packets += src[j].o_packets; 580 dst[j].i_bytes += src[j].i_bytes; 581 dst[j].i_packets += src[j].i_packets; 582 } 583 } 584 585 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 586 kfree(dst); 587 return 0; 588 } 589 590 static int rt_acct_proc_open(struct inode *inode, struct file *file) 591 { 592 return single_open(file, rt_acct_proc_show, NULL); 593 } 594 595 static const struct file_operations rt_acct_proc_fops = { 596 .owner = THIS_MODULE, 597 .open = rt_acct_proc_open, 598 .read = seq_read, 599 .llseek = seq_lseek, 600 .release = single_release, 601 }; 602 #endif 603 604 static int __net_init ip_rt_do_proc_init(struct net *net) 605 { 606 struct proc_dir_entry *pde; 607 608 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO, 609 &rt_cache_seq_fops); 610 if (!pde) 611 goto err1; 612 613 pde = proc_create("rt_cache", S_IRUGO, 614 net->proc_net_stat, &rt_cpu_seq_fops); 615 if (!pde) 616 goto err2; 617 618 #ifdef CONFIG_IP_ROUTE_CLASSID 619 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops); 620 if (!pde) 621 goto err3; 622 #endif 623 return 0; 624 625 #ifdef CONFIG_IP_ROUTE_CLASSID 626 err3: 627 remove_proc_entry("rt_cache", net->proc_net_stat); 628 #endif 629 err2: 630 remove_proc_entry("rt_cache", net->proc_net); 631 err1: 632 return -ENOMEM; 633 } 634 635 static void __net_exit ip_rt_do_proc_exit(struct net *net) 636 { 637 remove_proc_entry("rt_cache", net->proc_net_stat); 638 remove_proc_entry("rt_cache", net->proc_net); 639 #ifdef CONFIG_IP_ROUTE_CLASSID 640 remove_proc_entry("rt_acct", net->proc_net); 641 #endif 642 } 643 644 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 645 .init = ip_rt_do_proc_init, 646 .exit = ip_rt_do_proc_exit, 647 }; 648 649 static int __init ip_rt_proc_init(void) 650 { 651 return register_pernet_subsys(&ip_rt_proc_ops); 652 } 653 654 #else 655 static inline int ip_rt_proc_init(void) 656 { 657 return 0; 658 } 659 #endif /* CONFIG_PROC_FS */ 660 661 static inline void rt_free(struct rtable *rt) 662 { 663 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); 664 } 665 666 static inline void rt_drop(struct rtable *rt) 667 { 668 ip_rt_put(rt); 669 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free); 670 } 671 672 static inline int rt_fast_clean(struct rtable *rth) 673 { 674 /* Kill broadcast/multicast entries very aggresively, if they 675 collide in hash table with more useful entries */ 676 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) && 677 rt_is_input_route(rth) && rth->dst.rt_next; 678 } 679 680 static inline int rt_valuable(struct rtable *rth) 681 { 682 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) || 683 (rth->peer && rth->peer->pmtu_expires); 684 } 685 686 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2) 687 { 688 unsigned long age; 689 int ret = 0; 690 691 if (atomic_read(&rth->dst.__refcnt)) 692 goto out; 693 694 age = jiffies - rth->dst.lastuse; 695 if ((age <= tmo1 && !rt_fast_clean(rth)) || 696 (age <= tmo2 && rt_valuable(rth))) 697 goto out; 698 ret = 1; 699 out: return ret; 700 } 701 702 /* Bits of score are: 703 * 31: very valuable 704 * 30: not quite useless 705 * 29..0: usage counter 706 */ 707 static inline u32 rt_score(struct rtable *rt) 708 { 709 u32 score = jiffies - rt->dst.lastuse; 710 711 score = ~score & ~(3<<30); 712 713 if (rt_valuable(rt)) 714 score |= (1<<31); 715 716 if (rt_is_output_route(rt) || 717 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL))) 718 score |= (1<<30); 719 720 return score; 721 } 722 723 static inline bool rt_caching(const struct net *net) 724 { 725 return net->ipv4.current_rt_cache_rebuild_count <= 726 net->ipv4.sysctl_rt_cache_rebuild_count; 727 } 728 729 static inline bool compare_hash_inputs(const struct rtable *rt1, 730 const struct rtable *rt2) 731 { 732 return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) | 733 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) | 734 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0); 735 } 736 737 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2) 738 { 739 return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) | 740 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) | 741 (rt1->rt_mark ^ rt2->rt_mark) | 742 (rt1->rt_key_tos ^ rt2->rt_key_tos) | 743 (rt1->rt_route_iif ^ rt2->rt_route_iif) | 744 (rt1->rt_oif ^ rt2->rt_oif)) == 0; 745 } 746 747 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2) 748 { 749 return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev)); 750 } 751 752 static inline int rt_is_expired(struct rtable *rth) 753 { 754 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev)); 755 } 756 757 /* 758 * Perform a full scan of hash table and free all entries. 759 * Can be called by a softirq or a process. 760 * In the later case, we want to be reschedule if necessary 761 */ 762 static void rt_do_flush(struct net *net, int process_context) 763 { 764 unsigned int i; 765 struct rtable *rth, *next; 766 767 for (i = 0; i <= rt_hash_mask; i++) { 768 struct rtable __rcu **pprev; 769 struct rtable *list; 770 771 if (process_context && need_resched()) 772 cond_resched(); 773 rth = rcu_access_pointer(rt_hash_table[i].chain); 774 if (!rth) 775 continue; 776 777 spin_lock_bh(rt_hash_lock_addr(i)); 778 779 list = NULL; 780 pprev = &rt_hash_table[i].chain; 781 rth = rcu_dereference_protected(*pprev, 782 lockdep_is_held(rt_hash_lock_addr(i))); 783 784 while (rth) { 785 next = rcu_dereference_protected(rth->dst.rt_next, 786 lockdep_is_held(rt_hash_lock_addr(i))); 787 788 if (!net || 789 net_eq(dev_net(rth->dst.dev), net)) { 790 rcu_assign_pointer(*pprev, next); 791 rcu_assign_pointer(rth->dst.rt_next, list); 792 list = rth; 793 } else { 794 pprev = &rth->dst.rt_next; 795 } 796 rth = next; 797 } 798 799 spin_unlock_bh(rt_hash_lock_addr(i)); 800 801 for (; list; list = next) { 802 next = rcu_dereference_protected(list->dst.rt_next, 1); 803 rt_free(list); 804 } 805 } 806 } 807 808 /* 809 * While freeing expired entries, we compute average chain length 810 * and standard deviation, using fixed-point arithmetic. 811 * This to have an estimation of rt_chain_length_max 812 * rt_chain_length_max = max(elasticity, AVG + 4*SD) 813 * We use 3 bits for frational part, and 29 (or 61) for magnitude. 814 */ 815 816 #define FRACT_BITS 3 817 #define ONE (1UL << FRACT_BITS) 818 819 /* 820 * Given a hash chain and an item in this hash chain, 821 * find if a previous entry has the same hash_inputs 822 * (but differs on tos, mark or oif) 823 * Returns 0 if an alias is found. 824 * Returns ONE if rth has no alias before itself. 825 */ 826 static int has_noalias(const struct rtable *head, const struct rtable *rth) 827 { 828 const struct rtable *aux = head; 829 830 while (aux != rth) { 831 if (compare_hash_inputs(aux, rth)) 832 return 0; 833 aux = rcu_dereference_protected(aux->dst.rt_next, 1); 834 } 835 return ONE; 836 } 837 838 static void rt_check_expire(void) 839 { 840 static unsigned int rover; 841 unsigned int i = rover, goal; 842 struct rtable *rth; 843 struct rtable __rcu **rthp; 844 unsigned long samples = 0; 845 unsigned long sum = 0, sum2 = 0; 846 unsigned long delta; 847 u64 mult; 848 849 delta = jiffies - expires_ljiffies; 850 expires_ljiffies = jiffies; 851 mult = ((u64)delta) << rt_hash_log; 852 if (ip_rt_gc_timeout > 1) 853 do_div(mult, ip_rt_gc_timeout); 854 goal = (unsigned int)mult; 855 if (goal > rt_hash_mask) 856 goal = rt_hash_mask + 1; 857 for (; goal > 0; goal--) { 858 unsigned long tmo = ip_rt_gc_timeout; 859 unsigned long length; 860 861 i = (i + 1) & rt_hash_mask; 862 rthp = &rt_hash_table[i].chain; 863 864 if (need_resched()) 865 cond_resched(); 866 867 samples++; 868 869 if (rcu_dereference_raw(*rthp) == NULL) 870 continue; 871 length = 0; 872 spin_lock_bh(rt_hash_lock_addr(i)); 873 while ((rth = rcu_dereference_protected(*rthp, 874 lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) { 875 prefetch(rth->dst.rt_next); 876 if (rt_is_expired(rth)) { 877 *rthp = rth->dst.rt_next; 878 rt_free(rth); 879 continue; 880 } 881 if (rth->dst.expires) { 882 /* Entry is expired even if it is in use */ 883 if (time_before_eq(jiffies, rth->dst.expires)) { 884 nofree: 885 tmo >>= 1; 886 rthp = &rth->dst.rt_next; 887 /* 888 * We only count entries on 889 * a chain with equal hash inputs once 890 * so that entries for different QOS 891 * levels, and other non-hash input 892 * attributes don't unfairly skew 893 * the length computation 894 */ 895 length += has_noalias(rt_hash_table[i].chain, rth); 896 continue; 897 } 898 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) 899 goto nofree; 900 901 /* Cleanup aged off entries. */ 902 *rthp = rth->dst.rt_next; 903 rt_free(rth); 904 } 905 spin_unlock_bh(rt_hash_lock_addr(i)); 906 sum += length; 907 sum2 += length*length; 908 } 909 if (samples) { 910 unsigned long avg = sum / samples; 911 unsigned long sd = int_sqrt(sum2 / samples - avg*avg); 912 rt_chain_length_max = max_t(unsigned long, 913 ip_rt_gc_elasticity, 914 (avg + 4*sd) >> FRACT_BITS); 915 } 916 rover = i; 917 } 918 919 /* 920 * rt_worker_func() is run in process context. 921 * we call rt_check_expire() to scan part of the hash table 922 */ 923 static void rt_worker_func(struct work_struct *work) 924 { 925 rt_check_expire(); 926 schedule_delayed_work(&expires_work, ip_rt_gc_interval); 927 } 928 929 /* 930 * Perturbation of rt_genid by a small quantity [1..256] 931 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate() 932 * many times (2^24) without giving recent rt_genid. 933 * Jenkins hash is strong enough that litle changes of rt_genid are OK. 934 */ 935 static void rt_cache_invalidate(struct net *net) 936 { 937 unsigned char shuffle; 938 939 get_random_bytes(&shuffle, sizeof(shuffle)); 940 atomic_add(shuffle + 1U, &net->ipv4.rt_genid); 941 inetpeer_invalidate_tree(AF_INET); 942 } 943 944 /* 945 * delay < 0 : invalidate cache (fast : entries will be deleted later) 946 * delay >= 0 : invalidate & flush cache (can be long) 947 */ 948 void rt_cache_flush(struct net *net, int delay) 949 { 950 rt_cache_invalidate(net); 951 if (delay >= 0) 952 rt_do_flush(net, !in_softirq()); 953 } 954 955 /* Flush previous cache invalidated entries from the cache */ 956 void rt_cache_flush_batch(struct net *net) 957 { 958 rt_do_flush(net, !in_softirq()); 959 } 960 961 static void rt_emergency_hash_rebuild(struct net *net) 962 { 963 net_warn_ratelimited("Route hash chain too long!\n"); 964 rt_cache_invalidate(net); 965 } 966 967 /* 968 Short description of GC goals. 969 970 We want to build algorithm, which will keep routing cache 971 at some equilibrium point, when number of aged off entries 972 is kept approximately equal to newly generated ones. 973 974 Current expiration strength is variable "expire". 975 We try to adjust it dynamically, so that if networking 976 is idle expires is large enough to keep enough of warm entries, 977 and when load increases it reduces to limit cache size. 978 */ 979 980 static int rt_garbage_collect(struct dst_ops *ops) 981 { 982 static unsigned long expire = RT_GC_TIMEOUT; 983 static unsigned long last_gc; 984 static int rover; 985 static int equilibrium; 986 struct rtable *rth; 987 struct rtable __rcu **rthp; 988 unsigned long now = jiffies; 989 int goal; 990 int entries = dst_entries_get_fast(&ipv4_dst_ops); 991 992 /* 993 * Garbage collection is pretty expensive, 994 * do not make it too frequently. 995 */ 996 997 RT_CACHE_STAT_INC(gc_total); 998 999 if (now - last_gc < ip_rt_gc_min_interval && 1000 entries < ip_rt_max_size) { 1001 RT_CACHE_STAT_INC(gc_ignored); 1002 goto out; 1003 } 1004 1005 entries = dst_entries_get_slow(&ipv4_dst_ops); 1006 /* Calculate number of entries, which we want to expire now. */ 1007 goal = entries - (ip_rt_gc_elasticity << rt_hash_log); 1008 if (goal <= 0) { 1009 if (equilibrium < ipv4_dst_ops.gc_thresh) 1010 equilibrium = ipv4_dst_ops.gc_thresh; 1011 goal = entries - equilibrium; 1012 if (goal > 0) { 1013 equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1); 1014 goal = entries - equilibrium; 1015 } 1016 } else { 1017 /* We are in dangerous area. Try to reduce cache really 1018 * aggressively. 1019 */ 1020 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1); 1021 equilibrium = entries - goal; 1022 } 1023 1024 if (now - last_gc >= ip_rt_gc_min_interval) 1025 last_gc = now; 1026 1027 if (goal <= 0) { 1028 equilibrium += goal; 1029 goto work_done; 1030 } 1031 1032 do { 1033 int i, k; 1034 1035 for (i = rt_hash_mask, k = rover; i >= 0; i--) { 1036 unsigned long tmo = expire; 1037 1038 k = (k + 1) & rt_hash_mask; 1039 rthp = &rt_hash_table[k].chain; 1040 spin_lock_bh(rt_hash_lock_addr(k)); 1041 while ((rth = rcu_dereference_protected(*rthp, 1042 lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) { 1043 if (!rt_is_expired(rth) && 1044 !rt_may_expire(rth, tmo, expire)) { 1045 tmo >>= 1; 1046 rthp = &rth->dst.rt_next; 1047 continue; 1048 } 1049 *rthp = rth->dst.rt_next; 1050 rt_free(rth); 1051 goal--; 1052 } 1053 spin_unlock_bh(rt_hash_lock_addr(k)); 1054 if (goal <= 0) 1055 break; 1056 } 1057 rover = k; 1058 1059 if (goal <= 0) 1060 goto work_done; 1061 1062 /* Goal is not achieved. We stop process if: 1063 1064 - if expire reduced to zero. Otherwise, expire is halfed. 1065 - if table is not full. 1066 - if we are called from interrupt. 1067 - jiffies check is just fallback/debug loop breaker. 1068 We will not spin here for long time in any case. 1069 */ 1070 1071 RT_CACHE_STAT_INC(gc_goal_miss); 1072 1073 if (expire == 0) 1074 break; 1075 1076 expire >>= 1; 1077 1078 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size) 1079 goto out; 1080 } while (!in_softirq() && time_before_eq(jiffies, now)); 1081 1082 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size) 1083 goto out; 1084 if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size) 1085 goto out; 1086 net_warn_ratelimited("dst cache overflow\n"); 1087 RT_CACHE_STAT_INC(gc_dst_overflow); 1088 return 1; 1089 1090 work_done: 1091 expire += ip_rt_gc_min_interval; 1092 if (expire > ip_rt_gc_timeout || 1093 dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh || 1094 dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh) 1095 expire = ip_rt_gc_timeout; 1096 out: return 0; 1097 } 1098 1099 /* 1100 * Returns number of entries in a hash chain that have different hash_inputs 1101 */ 1102 static int slow_chain_length(const struct rtable *head) 1103 { 1104 int length = 0; 1105 const struct rtable *rth = head; 1106 1107 while (rth) { 1108 length += has_noalias(head, rth); 1109 rth = rcu_dereference_protected(rth->dst.rt_next, 1); 1110 } 1111 return length >> FRACT_BITS; 1112 } 1113 1114 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr) 1115 { 1116 static const __be32 inaddr_any = 0; 1117 struct net_device *dev = dst->dev; 1118 const __be32 *pkey = daddr; 1119 const struct rtable *rt; 1120 struct neighbour *n; 1121 1122 rt = (const struct rtable *) dst; 1123 1124 if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) 1125 pkey = &inaddr_any; 1126 else if (rt->rt_gateway) 1127 pkey = (const __be32 *) &rt->rt_gateway; 1128 1129 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); 1130 if (n) 1131 return n; 1132 return neigh_create(&arp_tbl, pkey, dev); 1133 } 1134 1135 static int rt_bind_neighbour(struct rtable *rt) 1136 { 1137 struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway); 1138 if (IS_ERR(n)) 1139 return PTR_ERR(n); 1140 dst_set_neighbour(&rt->dst, n); 1141 1142 return 0; 1143 } 1144 1145 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt, 1146 struct sk_buff *skb, int ifindex) 1147 { 1148 struct rtable *rth, *cand; 1149 struct rtable __rcu **rthp, **candp; 1150 unsigned long now; 1151 u32 min_score; 1152 int chain_length; 1153 int attempts = !in_softirq(); 1154 1155 restart: 1156 chain_length = 0; 1157 min_score = ~(u32)0; 1158 cand = NULL; 1159 candp = NULL; 1160 now = jiffies; 1161 1162 if (!rt_caching(dev_net(rt->dst.dev))) { 1163 /* 1164 * If we're not caching, just tell the caller we 1165 * were successful and don't touch the route. The 1166 * caller hold the sole reference to the cache entry, and 1167 * it will be released when the caller is done with it. 1168 * If we drop it here, the callers have no way to resolve routes 1169 * when we're not caching. Instead, just point *rp at rt, so 1170 * the caller gets a single use out of the route 1171 * Note that we do rt_free on this new route entry, so that 1172 * once its refcount hits zero, we are still able to reap it 1173 * (Thanks Alexey) 1174 * Note: To avoid expensive rcu stuff for this uncached dst, 1175 * we set DST_NOCACHE so that dst_release() can free dst without 1176 * waiting a grace period. 1177 */ 1178 1179 rt->dst.flags |= DST_NOCACHE; 1180 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) { 1181 int err = rt_bind_neighbour(rt); 1182 if (err) { 1183 net_warn_ratelimited("Neighbour table failure & not caching routes\n"); 1184 ip_rt_put(rt); 1185 return ERR_PTR(err); 1186 } 1187 } 1188 1189 goto skip_hashing; 1190 } 1191 1192 rthp = &rt_hash_table[hash].chain; 1193 1194 spin_lock_bh(rt_hash_lock_addr(hash)); 1195 while ((rth = rcu_dereference_protected(*rthp, 1196 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) { 1197 if (rt_is_expired(rth)) { 1198 *rthp = rth->dst.rt_next; 1199 rt_free(rth); 1200 continue; 1201 } 1202 if (compare_keys(rth, rt) && compare_netns(rth, rt)) { 1203 /* Put it first */ 1204 *rthp = rth->dst.rt_next; 1205 /* 1206 * Since lookup is lockfree, the deletion 1207 * must be visible to another weakly ordered CPU before 1208 * the insertion at the start of the hash chain. 1209 */ 1210 rcu_assign_pointer(rth->dst.rt_next, 1211 rt_hash_table[hash].chain); 1212 /* 1213 * Since lookup is lockfree, the update writes 1214 * must be ordered for consistency on SMP. 1215 */ 1216 rcu_assign_pointer(rt_hash_table[hash].chain, rth); 1217 1218 dst_use(&rth->dst, now); 1219 spin_unlock_bh(rt_hash_lock_addr(hash)); 1220 1221 rt_drop(rt); 1222 if (skb) 1223 skb_dst_set(skb, &rth->dst); 1224 return rth; 1225 } 1226 1227 if (!atomic_read(&rth->dst.__refcnt)) { 1228 u32 score = rt_score(rth); 1229 1230 if (score <= min_score) { 1231 cand = rth; 1232 candp = rthp; 1233 min_score = score; 1234 } 1235 } 1236 1237 chain_length++; 1238 1239 rthp = &rth->dst.rt_next; 1240 } 1241 1242 if (cand) { 1243 /* ip_rt_gc_elasticity used to be average length of chain 1244 * length, when exceeded gc becomes really aggressive. 1245 * 1246 * The second limit is less certain. At the moment it allows 1247 * only 2 entries per bucket. We will see. 1248 */ 1249 if (chain_length > ip_rt_gc_elasticity) { 1250 *candp = cand->dst.rt_next; 1251 rt_free(cand); 1252 } 1253 } else { 1254 if (chain_length > rt_chain_length_max && 1255 slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) { 1256 struct net *net = dev_net(rt->dst.dev); 1257 int num = ++net->ipv4.current_rt_cache_rebuild_count; 1258 if (!rt_caching(net)) { 1259 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n", 1260 rt->dst.dev->name, num); 1261 } 1262 rt_emergency_hash_rebuild(net); 1263 spin_unlock_bh(rt_hash_lock_addr(hash)); 1264 1265 hash = rt_hash(rt->rt_key_dst, rt->rt_key_src, 1266 ifindex, rt_genid(net)); 1267 goto restart; 1268 } 1269 } 1270 1271 /* Try to bind route to arp only if it is output 1272 route or unicast forwarding path. 1273 */ 1274 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) { 1275 int err = rt_bind_neighbour(rt); 1276 if (err) { 1277 spin_unlock_bh(rt_hash_lock_addr(hash)); 1278 1279 if (err != -ENOBUFS) { 1280 rt_drop(rt); 1281 return ERR_PTR(err); 1282 } 1283 1284 /* Neighbour tables are full and nothing 1285 can be released. Try to shrink route cache, 1286 it is most likely it holds some neighbour records. 1287 */ 1288 if (attempts-- > 0) { 1289 int saved_elasticity = ip_rt_gc_elasticity; 1290 int saved_int = ip_rt_gc_min_interval; 1291 ip_rt_gc_elasticity = 1; 1292 ip_rt_gc_min_interval = 0; 1293 rt_garbage_collect(&ipv4_dst_ops); 1294 ip_rt_gc_min_interval = saved_int; 1295 ip_rt_gc_elasticity = saved_elasticity; 1296 goto restart; 1297 } 1298 1299 net_warn_ratelimited("Neighbour table overflow\n"); 1300 rt_drop(rt); 1301 return ERR_PTR(-ENOBUFS); 1302 } 1303 } 1304 1305 rt->dst.rt_next = rt_hash_table[hash].chain; 1306 1307 /* 1308 * Since lookup is lockfree, we must make sure 1309 * previous writes to rt are committed to memory 1310 * before making rt visible to other CPUS. 1311 */ 1312 rcu_assign_pointer(rt_hash_table[hash].chain, rt); 1313 1314 spin_unlock_bh(rt_hash_lock_addr(hash)); 1315 1316 skip_hashing: 1317 if (skb) 1318 skb_dst_set(skb, &rt->dst); 1319 return rt; 1320 } 1321 1322 static atomic_t __rt_peer_genid = ATOMIC_INIT(0); 1323 1324 static u32 rt_peer_genid(void) 1325 { 1326 return atomic_read(&__rt_peer_genid); 1327 } 1328 1329 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create) 1330 { 1331 struct inet_peer *peer; 1332 1333 peer = inet_getpeer_v4(daddr, create); 1334 1335 if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL) 1336 inet_putpeer(peer); 1337 else 1338 rt->rt_peer_genid = rt_peer_genid(); 1339 } 1340 1341 /* 1342 * Peer allocation may fail only in serious out-of-memory conditions. However 1343 * we still can generate some output. 1344 * Random ID selection looks a bit dangerous because we have no chances to 1345 * select ID being unique in a reasonable period of time. 1346 * But broken packet identifier may be better than no packet at all. 1347 */ 1348 static void ip_select_fb_ident(struct iphdr *iph) 1349 { 1350 static DEFINE_SPINLOCK(ip_fb_id_lock); 1351 static u32 ip_fallback_id; 1352 u32 salt; 1353 1354 spin_lock_bh(&ip_fb_id_lock); 1355 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr); 1356 iph->id = htons(salt & 0xFFFF); 1357 ip_fallback_id = salt; 1358 spin_unlock_bh(&ip_fb_id_lock); 1359 } 1360 1361 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more) 1362 { 1363 struct rtable *rt = (struct rtable *) dst; 1364 1365 if (rt && !(rt->dst.flags & DST_NOPEER)) { 1366 if (rt->peer == NULL) 1367 rt_bind_peer(rt, rt->rt_dst, 1); 1368 1369 /* If peer is attached to destination, it is never detached, 1370 so that we need not to grab a lock to dereference it. 1371 */ 1372 if (rt->peer) { 1373 iph->id = htons(inet_getid(rt->peer, more)); 1374 return; 1375 } 1376 } else if (!rt) 1377 pr_debug("rt_bind_peer(0) @%p\n", __builtin_return_address(0)); 1378 1379 ip_select_fb_ident(iph); 1380 } 1381 EXPORT_SYMBOL(__ip_select_ident); 1382 1383 static void rt_del(unsigned int hash, struct rtable *rt) 1384 { 1385 struct rtable __rcu **rthp; 1386 struct rtable *aux; 1387 1388 rthp = &rt_hash_table[hash].chain; 1389 spin_lock_bh(rt_hash_lock_addr(hash)); 1390 ip_rt_put(rt); 1391 while ((aux = rcu_dereference_protected(*rthp, 1392 lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) { 1393 if (aux == rt || rt_is_expired(aux)) { 1394 *rthp = aux->dst.rt_next; 1395 rt_free(aux); 1396 continue; 1397 } 1398 rthp = &aux->dst.rt_next; 1399 } 1400 spin_unlock_bh(rt_hash_lock_addr(hash)); 1401 } 1402 1403 static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer) 1404 { 1405 struct rtable *rt = (struct rtable *) dst; 1406 __be32 orig_gw = rt->rt_gateway; 1407 struct neighbour *n, *old_n; 1408 1409 dst_confirm(&rt->dst); 1410 1411 rt->rt_gateway = peer->redirect_learned.a4; 1412 1413 n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway); 1414 if (IS_ERR(n)) { 1415 rt->rt_gateway = orig_gw; 1416 return; 1417 } 1418 old_n = xchg(&rt->dst._neighbour, n); 1419 if (old_n) 1420 neigh_release(old_n); 1421 if (!(n->nud_state & NUD_VALID)) { 1422 neigh_event_send(n, NULL); 1423 } else { 1424 rt->rt_flags |= RTCF_REDIRECTED; 1425 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 1426 } 1427 } 1428 1429 /* called in rcu_read_lock() section */ 1430 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, 1431 __be32 saddr, struct net_device *dev) 1432 { 1433 int s, i; 1434 struct in_device *in_dev = __in_dev_get_rcu(dev); 1435 __be32 skeys[2] = { saddr, 0 }; 1436 int ikeys[2] = { dev->ifindex, 0 }; 1437 struct inet_peer *peer; 1438 struct net *net; 1439 1440 if (!in_dev) 1441 return; 1442 1443 net = dev_net(dev); 1444 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 1445 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 1446 ipv4_is_zeronet(new_gw)) 1447 goto reject_redirect; 1448 1449 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 1450 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 1451 goto reject_redirect; 1452 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 1453 goto reject_redirect; 1454 } else { 1455 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 1456 goto reject_redirect; 1457 } 1458 1459 for (s = 0; s < 2; s++) { 1460 for (i = 0; i < 2; i++) { 1461 unsigned int hash; 1462 struct rtable __rcu **rthp; 1463 struct rtable *rt; 1464 1465 hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net)); 1466 1467 rthp = &rt_hash_table[hash].chain; 1468 1469 while ((rt = rcu_dereference(*rthp)) != NULL) { 1470 rthp = &rt->dst.rt_next; 1471 1472 if (rt->rt_key_dst != daddr || 1473 rt->rt_key_src != skeys[s] || 1474 rt->rt_oif != ikeys[i] || 1475 rt_is_input_route(rt) || 1476 rt_is_expired(rt) || 1477 !net_eq(dev_net(rt->dst.dev), net) || 1478 rt->dst.error || 1479 rt->dst.dev != dev || 1480 rt->rt_gateway != old_gw) 1481 continue; 1482 1483 if (!rt->peer) 1484 rt_bind_peer(rt, rt->rt_dst, 1); 1485 1486 peer = rt->peer; 1487 if (peer) { 1488 if (peer->redirect_learned.a4 != new_gw) { 1489 peer->redirect_learned.a4 = new_gw; 1490 atomic_inc(&__rt_peer_genid); 1491 } 1492 check_peer_redir(&rt->dst, peer); 1493 } 1494 } 1495 } 1496 } 1497 return; 1498 1499 reject_redirect: 1500 #ifdef CONFIG_IP_ROUTE_VERBOSE 1501 if (IN_DEV_LOG_MARTIANS(in_dev)) 1502 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 1503 " Advised path = %pI4 -> %pI4\n", 1504 &old_gw, dev->name, &new_gw, 1505 &saddr, &daddr); 1506 #endif 1507 ; 1508 } 1509 1510 static bool peer_pmtu_expired(struct inet_peer *peer) 1511 { 1512 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires); 1513 1514 return orig && 1515 time_after_eq(jiffies, orig) && 1516 cmpxchg(&peer->pmtu_expires, orig, 0) == orig; 1517 } 1518 1519 static bool peer_pmtu_cleaned(struct inet_peer *peer) 1520 { 1521 unsigned long orig = ACCESS_ONCE(peer->pmtu_expires); 1522 1523 return orig && 1524 cmpxchg(&peer->pmtu_expires, orig, 0) == orig; 1525 } 1526 1527 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 1528 { 1529 struct rtable *rt = (struct rtable *)dst; 1530 struct dst_entry *ret = dst; 1531 1532 if (rt) { 1533 if (dst->obsolete > 0) { 1534 ip_rt_put(rt); 1535 ret = NULL; 1536 } else if (rt->rt_flags & RTCF_REDIRECTED) { 1537 unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src, 1538 rt->rt_oif, 1539 rt_genid(dev_net(dst->dev))); 1540 rt_del(hash, rt); 1541 ret = NULL; 1542 } else if (rt->peer && peer_pmtu_expired(rt->peer)) { 1543 dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig); 1544 } 1545 } 1546 return ret; 1547 } 1548 1549 /* 1550 * Algorithm: 1551 * 1. The first ip_rt_redirect_number redirects are sent 1552 * with exponential backoff, then we stop sending them at all, 1553 * assuming that the host ignores our redirects. 1554 * 2. If we did not see packets requiring redirects 1555 * during ip_rt_redirect_silence, we assume that the host 1556 * forgot redirected route and start to send redirects again. 1557 * 1558 * This algorithm is much cheaper and more intelligent than dumb load limiting 1559 * in icmp.c. 1560 * 1561 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 1562 * and "frag. need" (breaks PMTU discovery) in icmp.c. 1563 */ 1564 1565 void ip_rt_send_redirect(struct sk_buff *skb) 1566 { 1567 struct rtable *rt = skb_rtable(skb); 1568 struct in_device *in_dev; 1569 struct inet_peer *peer; 1570 int log_martians; 1571 1572 rcu_read_lock(); 1573 in_dev = __in_dev_get_rcu(rt->dst.dev); 1574 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 1575 rcu_read_unlock(); 1576 return; 1577 } 1578 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 1579 rcu_read_unlock(); 1580 1581 if (!rt->peer) 1582 rt_bind_peer(rt, rt->rt_dst, 1); 1583 peer = rt->peer; 1584 if (!peer) { 1585 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); 1586 return; 1587 } 1588 1589 /* No redirected packets during ip_rt_redirect_silence; 1590 * reset the algorithm. 1591 */ 1592 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 1593 peer->rate_tokens = 0; 1594 1595 /* Too many ignored redirects; do not send anything 1596 * set dst.rate_last to the last seen redirected packet. 1597 */ 1598 if (peer->rate_tokens >= ip_rt_redirect_number) { 1599 peer->rate_last = jiffies; 1600 return; 1601 } 1602 1603 /* Check for load limit; set rate_last to the latest sent 1604 * redirect. 1605 */ 1606 if (peer->rate_tokens == 0 || 1607 time_after(jiffies, 1608 (peer->rate_last + 1609 (ip_rt_redirect_load << peer->rate_tokens)))) { 1610 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); 1611 peer->rate_last = jiffies; 1612 ++peer->rate_tokens; 1613 #ifdef CONFIG_IP_ROUTE_VERBOSE 1614 if (log_martians && 1615 peer->rate_tokens == ip_rt_redirect_number) 1616 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 1617 &ip_hdr(skb)->saddr, rt->rt_iif, 1618 &rt->rt_dst, &rt->rt_gateway); 1619 #endif 1620 } 1621 } 1622 1623 static int ip_error(struct sk_buff *skb) 1624 { 1625 struct rtable *rt = skb_rtable(skb); 1626 struct inet_peer *peer; 1627 unsigned long now; 1628 bool send; 1629 int code; 1630 1631 switch (rt->dst.error) { 1632 case EINVAL: 1633 default: 1634 goto out; 1635 case EHOSTUNREACH: 1636 code = ICMP_HOST_UNREACH; 1637 break; 1638 case ENETUNREACH: 1639 code = ICMP_NET_UNREACH; 1640 IP_INC_STATS_BH(dev_net(rt->dst.dev), 1641 IPSTATS_MIB_INNOROUTES); 1642 break; 1643 case EACCES: 1644 code = ICMP_PKT_FILTERED; 1645 break; 1646 } 1647 1648 if (!rt->peer) 1649 rt_bind_peer(rt, rt->rt_dst, 1); 1650 peer = rt->peer; 1651 1652 send = true; 1653 if (peer) { 1654 now = jiffies; 1655 peer->rate_tokens += now - peer->rate_last; 1656 if (peer->rate_tokens > ip_rt_error_burst) 1657 peer->rate_tokens = ip_rt_error_burst; 1658 peer->rate_last = now; 1659 if (peer->rate_tokens >= ip_rt_error_cost) 1660 peer->rate_tokens -= ip_rt_error_cost; 1661 else 1662 send = false; 1663 } 1664 if (send) 1665 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1666 1667 out: kfree_skb(skb); 1668 return 0; 1669 } 1670 1671 /* 1672 * The last two values are not from the RFC but 1673 * are needed for AMPRnet AX.25 paths. 1674 */ 1675 1676 static const unsigned short mtu_plateau[] = 1677 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 }; 1678 1679 static inline unsigned short guess_mtu(unsigned short old_mtu) 1680 { 1681 int i; 1682 1683 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++) 1684 if (old_mtu > mtu_plateau[i]) 1685 return mtu_plateau[i]; 1686 return 68; 1687 } 1688 1689 unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph, 1690 unsigned short new_mtu, 1691 struct net_device *dev) 1692 { 1693 unsigned short old_mtu = ntohs(iph->tot_len); 1694 unsigned short est_mtu = 0; 1695 struct inet_peer *peer; 1696 1697 peer = inet_getpeer_v4(iph->daddr, 1); 1698 if (peer) { 1699 unsigned short mtu = new_mtu; 1700 1701 if (new_mtu < 68 || new_mtu >= old_mtu) { 1702 /* BSD 4.2 derived systems incorrectly adjust 1703 * tot_len by the IP header length, and report 1704 * a zero MTU in the ICMP message. 1705 */ 1706 if (mtu == 0 && 1707 old_mtu >= 68 + (iph->ihl << 2)) 1708 old_mtu -= iph->ihl << 2; 1709 mtu = guess_mtu(old_mtu); 1710 } 1711 1712 if (mtu < ip_rt_min_pmtu) 1713 mtu = ip_rt_min_pmtu; 1714 if (!peer->pmtu_expires || mtu < peer->pmtu_learned) { 1715 unsigned long pmtu_expires; 1716 1717 pmtu_expires = jiffies + ip_rt_mtu_expires; 1718 if (!pmtu_expires) 1719 pmtu_expires = 1UL; 1720 1721 est_mtu = mtu; 1722 peer->pmtu_learned = mtu; 1723 peer->pmtu_expires = pmtu_expires; 1724 atomic_inc(&__rt_peer_genid); 1725 } 1726 1727 inet_putpeer(peer); 1728 } 1729 return est_mtu ? : new_mtu; 1730 } 1731 1732 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer) 1733 { 1734 unsigned long expires = ACCESS_ONCE(peer->pmtu_expires); 1735 1736 if (!expires) 1737 return; 1738 if (time_before(jiffies, expires)) { 1739 u32 orig_dst_mtu = dst_mtu(dst); 1740 if (peer->pmtu_learned < orig_dst_mtu) { 1741 if (!peer->pmtu_orig) 1742 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU); 1743 dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned); 1744 } 1745 } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires) 1746 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig); 1747 } 1748 1749 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu) 1750 { 1751 struct rtable *rt = (struct rtable *) dst; 1752 struct inet_peer *peer; 1753 1754 dst_confirm(dst); 1755 1756 if (!rt->peer) 1757 rt_bind_peer(rt, rt->rt_dst, 1); 1758 peer = rt->peer; 1759 if (peer) { 1760 unsigned long pmtu_expires = ACCESS_ONCE(peer->pmtu_expires); 1761 1762 if (mtu < ip_rt_min_pmtu) 1763 mtu = ip_rt_min_pmtu; 1764 if (!pmtu_expires || mtu < peer->pmtu_learned) { 1765 1766 pmtu_expires = jiffies + ip_rt_mtu_expires; 1767 if (!pmtu_expires) 1768 pmtu_expires = 1UL; 1769 1770 peer->pmtu_learned = mtu; 1771 peer->pmtu_expires = pmtu_expires; 1772 1773 atomic_inc(&__rt_peer_genid); 1774 rt->rt_peer_genid = rt_peer_genid(); 1775 } 1776 check_peer_pmtu(dst, peer); 1777 } 1778 } 1779 1780 1781 static void ipv4_validate_peer(struct rtable *rt) 1782 { 1783 if (rt->rt_peer_genid != rt_peer_genid()) { 1784 struct inet_peer *peer; 1785 1786 if (!rt->peer) 1787 rt_bind_peer(rt, rt->rt_dst, 0); 1788 1789 peer = rt->peer; 1790 if (peer) { 1791 check_peer_pmtu(&rt->dst, peer); 1792 1793 if (peer->redirect_learned.a4 && 1794 peer->redirect_learned.a4 != rt->rt_gateway) 1795 check_peer_redir(&rt->dst, peer); 1796 } 1797 1798 rt->rt_peer_genid = rt_peer_genid(); 1799 } 1800 } 1801 1802 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1803 { 1804 struct rtable *rt = (struct rtable *) dst; 1805 1806 if (rt_is_expired(rt)) 1807 return NULL; 1808 ipv4_validate_peer(rt); 1809 return dst; 1810 } 1811 1812 static void ipv4_dst_destroy(struct dst_entry *dst) 1813 { 1814 struct rtable *rt = (struct rtable *) dst; 1815 struct inet_peer *peer = rt->peer; 1816 1817 if (rt->fi) { 1818 fib_info_put(rt->fi); 1819 rt->fi = NULL; 1820 } 1821 if (peer) { 1822 rt->peer = NULL; 1823 inet_putpeer(peer); 1824 } 1825 } 1826 1827 1828 static void ipv4_link_failure(struct sk_buff *skb) 1829 { 1830 struct rtable *rt; 1831 1832 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1833 1834 rt = skb_rtable(skb); 1835 if (rt && rt->peer && peer_pmtu_cleaned(rt->peer)) 1836 dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig); 1837 } 1838 1839 static int ip_rt_bug(struct sk_buff *skb) 1840 { 1841 pr_debug("%s: %pI4 -> %pI4, %s\n", 1842 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1843 skb->dev ? skb->dev->name : "?"); 1844 kfree_skb(skb); 1845 WARN_ON(1); 1846 return 0; 1847 } 1848 1849 /* 1850 We do not cache source address of outgoing interface, 1851 because it is used only by IP RR, TS and SRR options, 1852 so that it out of fast path. 1853 1854 BTW remember: "addr" is allowed to be not aligned 1855 in IP options! 1856 */ 1857 1858 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1859 { 1860 __be32 src; 1861 1862 if (rt_is_output_route(rt)) 1863 src = ip_hdr(skb)->saddr; 1864 else { 1865 struct fib_result res; 1866 struct flowi4 fl4; 1867 struct iphdr *iph; 1868 1869 iph = ip_hdr(skb); 1870 1871 memset(&fl4, 0, sizeof(fl4)); 1872 fl4.daddr = iph->daddr; 1873 fl4.saddr = iph->saddr; 1874 fl4.flowi4_tos = RT_TOS(iph->tos); 1875 fl4.flowi4_oif = rt->dst.dev->ifindex; 1876 fl4.flowi4_iif = skb->dev->ifindex; 1877 fl4.flowi4_mark = skb->mark; 1878 1879 rcu_read_lock(); 1880 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0) 1881 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1882 else 1883 src = inet_select_addr(rt->dst.dev, rt->rt_gateway, 1884 RT_SCOPE_UNIVERSE); 1885 rcu_read_unlock(); 1886 } 1887 memcpy(addr, &src, 4); 1888 } 1889 1890 #ifdef CONFIG_IP_ROUTE_CLASSID 1891 static void set_class_tag(struct rtable *rt, u32 tag) 1892 { 1893 if (!(rt->dst.tclassid & 0xFFFF)) 1894 rt->dst.tclassid |= tag & 0xFFFF; 1895 if (!(rt->dst.tclassid & 0xFFFF0000)) 1896 rt->dst.tclassid |= tag & 0xFFFF0000; 1897 } 1898 #endif 1899 1900 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1901 { 1902 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); 1903 1904 if (advmss == 0) { 1905 advmss = max_t(unsigned int, dst->dev->mtu - 40, 1906 ip_rt_min_advmss); 1907 if (advmss > 65535 - 40) 1908 advmss = 65535 - 40; 1909 } 1910 return advmss; 1911 } 1912 1913 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1914 { 1915 const struct rtable *rt = (const struct rtable *) dst; 1916 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 1917 1918 if (mtu && rt_is_output_route(rt)) 1919 return mtu; 1920 1921 mtu = dst->dev->mtu; 1922 1923 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { 1924 1925 if (rt->rt_gateway != rt->rt_dst && mtu > 576) 1926 mtu = 576; 1927 } 1928 1929 if (mtu > IP_MAX_MTU) 1930 mtu = IP_MAX_MTU; 1931 1932 return mtu; 1933 } 1934 1935 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4, 1936 struct fib_info *fi) 1937 { 1938 struct inet_peer *peer; 1939 int create = 0; 1940 1941 /* If a peer entry exists for this destination, we must hook 1942 * it up in order to get at cached metrics. 1943 */ 1944 if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS)) 1945 create = 1; 1946 1947 rt->peer = peer = inet_getpeer_v4(rt->rt_dst, create); 1948 if (peer) { 1949 rt->rt_peer_genid = rt_peer_genid(); 1950 if (inet_metrics_new(peer)) 1951 memcpy(peer->metrics, fi->fib_metrics, 1952 sizeof(u32) * RTAX_MAX); 1953 dst_init_metrics(&rt->dst, peer->metrics, false); 1954 1955 check_peer_pmtu(&rt->dst, peer); 1956 1957 if (peer->redirect_learned.a4 && 1958 peer->redirect_learned.a4 != rt->rt_gateway) { 1959 rt->rt_gateway = peer->redirect_learned.a4; 1960 rt->rt_flags |= RTCF_REDIRECTED; 1961 } 1962 } else { 1963 if (fi->fib_metrics != (u32 *) dst_default_metrics) { 1964 rt->fi = fi; 1965 atomic_inc(&fi->fib_clntref); 1966 } 1967 dst_init_metrics(&rt->dst, fi->fib_metrics, true); 1968 } 1969 } 1970 1971 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4, 1972 const struct fib_result *res, 1973 struct fib_info *fi, u16 type, u32 itag) 1974 { 1975 struct dst_entry *dst = &rt->dst; 1976 1977 if (fi) { 1978 if (FIB_RES_GW(*res) && 1979 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) 1980 rt->rt_gateway = FIB_RES_GW(*res); 1981 rt_init_metrics(rt, fl4, fi); 1982 #ifdef CONFIG_IP_ROUTE_CLASSID 1983 dst->tclassid = FIB_RES_NH(*res).nh_tclassid; 1984 #endif 1985 } 1986 1987 if (dst_mtu(dst) > IP_MAX_MTU) 1988 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU); 1989 if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40) 1990 dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40); 1991 1992 #ifdef CONFIG_IP_ROUTE_CLASSID 1993 #ifdef CONFIG_IP_MULTIPLE_TABLES 1994 set_class_tag(rt, fib_rules_tclass(res)); 1995 #endif 1996 set_class_tag(rt, itag); 1997 #endif 1998 } 1999 2000 static struct rtable *rt_dst_alloc(struct net_device *dev, 2001 bool nopolicy, bool noxfrm) 2002 { 2003 return dst_alloc(&ipv4_dst_ops, dev, 1, -1, 2004 DST_HOST | 2005 (nopolicy ? DST_NOPOLICY : 0) | 2006 (noxfrm ? DST_NOXFRM : 0)); 2007 } 2008 2009 /* called in rcu_read_lock() section */ 2010 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2011 u8 tos, struct net_device *dev, int our) 2012 { 2013 unsigned int hash; 2014 struct rtable *rth; 2015 __be32 spec_dst; 2016 struct in_device *in_dev = __in_dev_get_rcu(dev); 2017 u32 itag = 0; 2018 int err; 2019 2020 /* Primary sanity checks. */ 2021 2022 if (in_dev == NULL) 2023 return -EINVAL; 2024 2025 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 2026 ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP)) 2027 goto e_inval; 2028 2029 if (ipv4_is_zeronet(saddr)) { 2030 if (!ipv4_is_local_multicast(daddr)) 2031 goto e_inval; 2032 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); 2033 } else { 2034 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst, 2035 &itag); 2036 if (err < 0) 2037 goto e_err; 2038 } 2039 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, 2040 IN_DEV_CONF_GET(in_dev, NOPOLICY), false); 2041 if (!rth) 2042 goto e_nobufs; 2043 2044 #ifdef CONFIG_IP_ROUTE_CLASSID 2045 rth->dst.tclassid = itag; 2046 #endif 2047 rth->dst.output = ip_rt_bug; 2048 2049 rth->rt_key_dst = daddr; 2050 rth->rt_key_src = saddr; 2051 rth->rt_genid = rt_genid(dev_net(dev)); 2052 rth->rt_flags = RTCF_MULTICAST; 2053 rth->rt_type = RTN_MULTICAST; 2054 rth->rt_key_tos = tos; 2055 rth->rt_dst = daddr; 2056 rth->rt_src = saddr; 2057 rth->rt_route_iif = dev->ifindex; 2058 rth->rt_iif = dev->ifindex; 2059 rth->rt_oif = 0; 2060 rth->rt_mark = skb->mark; 2061 rth->rt_gateway = daddr; 2062 rth->rt_spec_dst= spec_dst; 2063 rth->rt_peer_genid = 0; 2064 rth->peer = NULL; 2065 rth->fi = NULL; 2066 if (our) { 2067 rth->dst.input= ip_local_deliver; 2068 rth->rt_flags |= RTCF_LOCAL; 2069 } 2070 2071 #ifdef CONFIG_IP_MROUTE 2072 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 2073 rth->dst.input = ip_mr_input; 2074 #endif 2075 RT_CACHE_STAT_INC(in_slow_mc); 2076 2077 hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev))); 2078 rth = rt_intern_hash(hash, rth, skb, dev->ifindex); 2079 return IS_ERR(rth) ? PTR_ERR(rth) : 0; 2080 2081 e_nobufs: 2082 return -ENOBUFS; 2083 e_inval: 2084 return -EINVAL; 2085 e_err: 2086 return err; 2087 } 2088 2089 2090 static void ip_handle_martian_source(struct net_device *dev, 2091 struct in_device *in_dev, 2092 struct sk_buff *skb, 2093 __be32 daddr, 2094 __be32 saddr) 2095 { 2096 RT_CACHE_STAT_INC(in_martian_src); 2097 #ifdef CONFIG_IP_ROUTE_VERBOSE 2098 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 2099 /* 2100 * RFC1812 recommendation, if source is martian, 2101 * the only hint is MAC header. 2102 */ 2103 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 2104 &daddr, &saddr, dev->name); 2105 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 2106 print_hex_dump(KERN_WARNING, "ll header: ", 2107 DUMP_PREFIX_OFFSET, 16, 1, 2108 skb_mac_header(skb), 2109 dev->hard_header_len, true); 2110 } 2111 } 2112 #endif 2113 } 2114 2115 /* called in rcu_read_lock() section */ 2116 static int __mkroute_input(struct sk_buff *skb, 2117 const struct fib_result *res, 2118 struct in_device *in_dev, 2119 __be32 daddr, __be32 saddr, u32 tos, 2120 struct rtable **result) 2121 { 2122 struct rtable *rth; 2123 int err; 2124 struct in_device *out_dev; 2125 unsigned int flags = 0; 2126 __be32 spec_dst; 2127 u32 itag; 2128 2129 /* get a working reference to the output device */ 2130 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 2131 if (out_dev == NULL) { 2132 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 2133 return -EINVAL; 2134 } 2135 2136 2137 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 2138 in_dev->dev, &spec_dst, &itag); 2139 if (err < 0) { 2140 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 2141 saddr); 2142 2143 goto cleanup; 2144 } 2145 2146 if (err) 2147 flags |= RTCF_DIRECTSRC; 2148 2149 if (out_dev == in_dev && err && 2150 (IN_DEV_SHARED_MEDIA(out_dev) || 2151 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 2152 flags |= RTCF_DOREDIRECT; 2153 2154 if (skb->protocol != htons(ETH_P_IP)) { 2155 /* Not IP (i.e. ARP). Do not create route, if it is 2156 * invalid for proxy arp. DNAT routes are always valid. 2157 * 2158 * Proxy arp feature have been extended to allow, ARP 2159 * replies back to the same interface, to support 2160 * Private VLAN switch technologies. See arp.c. 2161 */ 2162 if (out_dev == in_dev && 2163 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 2164 err = -EINVAL; 2165 goto cleanup; 2166 } 2167 } 2168 2169 rth = rt_dst_alloc(out_dev->dev, 2170 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2171 IN_DEV_CONF_GET(out_dev, NOXFRM)); 2172 if (!rth) { 2173 err = -ENOBUFS; 2174 goto cleanup; 2175 } 2176 2177 rth->rt_key_dst = daddr; 2178 rth->rt_key_src = saddr; 2179 rth->rt_genid = rt_genid(dev_net(rth->dst.dev)); 2180 rth->rt_flags = flags; 2181 rth->rt_type = res->type; 2182 rth->rt_key_tos = tos; 2183 rth->rt_dst = daddr; 2184 rth->rt_src = saddr; 2185 rth->rt_route_iif = in_dev->dev->ifindex; 2186 rth->rt_iif = in_dev->dev->ifindex; 2187 rth->rt_oif = 0; 2188 rth->rt_mark = skb->mark; 2189 rth->rt_gateway = daddr; 2190 rth->rt_spec_dst= spec_dst; 2191 rth->rt_peer_genid = 0; 2192 rth->peer = NULL; 2193 rth->fi = NULL; 2194 2195 rth->dst.input = ip_forward; 2196 rth->dst.output = ip_output; 2197 2198 rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag); 2199 2200 *result = rth; 2201 err = 0; 2202 cleanup: 2203 return err; 2204 } 2205 2206 static int ip_mkroute_input(struct sk_buff *skb, 2207 struct fib_result *res, 2208 const struct flowi4 *fl4, 2209 struct in_device *in_dev, 2210 __be32 daddr, __be32 saddr, u32 tos) 2211 { 2212 struct rtable *rth = NULL; 2213 int err; 2214 unsigned int hash; 2215 2216 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2217 if (res->fi && res->fi->fib_nhs > 1) 2218 fib_select_multipath(res); 2219 #endif 2220 2221 /* create a routing cache entry */ 2222 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth); 2223 if (err) 2224 return err; 2225 2226 /* put it into the cache */ 2227 hash = rt_hash(daddr, saddr, fl4->flowi4_iif, 2228 rt_genid(dev_net(rth->dst.dev))); 2229 rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif); 2230 if (IS_ERR(rth)) 2231 return PTR_ERR(rth); 2232 return 0; 2233 } 2234 2235 /* 2236 * NOTE. We drop all the packets that has local source 2237 * addresses, because every properly looped back packet 2238 * must have correct destination already attached by output routine. 2239 * 2240 * Such approach solves two big problems: 2241 * 1. Not simplex devices are handled properly. 2242 * 2. IP spoofing attempts are filtered with 100% of guarantee. 2243 * called with rcu_read_lock() 2244 */ 2245 2246 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2247 u8 tos, struct net_device *dev) 2248 { 2249 struct fib_result res; 2250 struct in_device *in_dev = __in_dev_get_rcu(dev); 2251 struct flowi4 fl4; 2252 unsigned int flags = 0; 2253 u32 itag = 0; 2254 struct rtable *rth; 2255 unsigned int hash; 2256 __be32 spec_dst; 2257 int err = -EINVAL; 2258 struct net *net = dev_net(dev); 2259 2260 /* IP on this device is disabled. */ 2261 2262 if (!in_dev) 2263 goto out; 2264 2265 /* Check for the most weird martians, which can be not detected 2266 by fib_lookup. 2267 */ 2268 2269 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 2270 ipv4_is_loopback(saddr)) 2271 goto martian_source; 2272 2273 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 2274 goto brd_input; 2275 2276 /* Accept zero addresses only to limited broadcast; 2277 * I even do not know to fix it or not. Waiting for complains :-) 2278 */ 2279 if (ipv4_is_zeronet(saddr)) 2280 goto martian_source; 2281 2282 if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr)) 2283 goto martian_destination; 2284 2285 /* 2286 * Now we are ready to route packet. 2287 */ 2288 fl4.flowi4_oif = 0; 2289 fl4.flowi4_iif = dev->ifindex; 2290 fl4.flowi4_mark = skb->mark; 2291 fl4.flowi4_tos = tos; 2292 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 2293 fl4.daddr = daddr; 2294 fl4.saddr = saddr; 2295 err = fib_lookup(net, &fl4, &res); 2296 if (err != 0) { 2297 if (!IN_DEV_FORWARD(in_dev)) 2298 goto e_hostunreach; 2299 goto no_route; 2300 } 2301 2302 RT_CACHE_STAT_INC(in_slow_tot); 2303 2304 if (res.type == RTN_BROADCAST) 2305 goto brd_input; 2306 2307 if (res.type == RTN_LOCAL) { 2308 err = fib_validate_source(skb, saddr, daddr, tos, 2309 net->loopback_dev->ifindex, 2310 dev, &spec_dst, &itag); 2311 if (err < 0) 2312 goto martian_source_keep_err; 2313 if (err) 2314 flags |= RTCF_DIRECTSRC; 2315 spec_dst = daddr; 2316 goto local_input; 2317 } 2318 2319 if (!IN_DEV_FORWARD(in_dev)) 2320 goto e_hostunreach; 2321 if (res.type != RTN_UNICAST) 2322 goto martian_destination; 2323 2324 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); 2325 out: return err; 2326 2327 brd_input: 2328 if (skb->protocol != htons(ETH_P_IP)) 2329 goto e_inval; 2330 2331 if (ipv4_is_zeronet(saddr)) 2332 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); 2333 else { 2334 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, &spec_dst, 2335 &itag); 2336 if (err < 0) 2337 goto martian_source_keep_err; 2338 if (err) 2339 flags |= RTCF_DIRECTSRC; 2340 } 2341 flags |= RTCF_BROADCAST; 2342 res.type = RTN_BROADCAST; 2343 RT_CACHE_STAT_INC(in_brd); 2344 2345 local_input: 2346 rth = rt_dst_alloc(net->loopback_dev, 2347 IN_DEV_CONF_GET(in_dev, NOPOLICY), false); 2348 if (!rth) 2349 goto e_nobufs; 2350 2351 rth->dst.input= ip_local_deliver; 2352 rth->dst.output= ip_rt_bug; 2353 #ifdef CONFIG_IP_ROUTE_CLASSID 2354 rth->dst.tclassid = itag; 2355 #endif 2356 2357 rth->rt_key_dst = daddr; 2358 rth->rt_key_src = saddr; 2359 rth->rt_genid = rt_genid(net); 2360 rth->rt_flags = flags|RTCF_LOCAL; 2361 rth->rt_type = res.type; 2362 rth->rt_key_tos = tos; 2363 rth->rt_dst = daddr; 2364 rth->rt_src = saddr; 2365 #ifdef CONFIG_IP_ROUTE_CLASSID 2366 rth->dst.tclassid = itag; 2367 #endif 2368 rth->rt_route_iif = dev->ifindex; 2369 rth->rt_iif = dev->ifindex; 2370 rth->rt_oif = 0; 2371 rth->rt_mark = skb->mark; 2372 rth->rt_gateway = daddr; 2373 rth->rt_spec_dst= spec_dst; 2374 rth->rt_peer_genid = 0; 2375 rth->peer = NULL; 2376 rth->fi = NULL; 2377 if (res.type == RTN_UNREACHABLE) { 2378 rth->dst.input= ip_error; 2379 rth->dst.error= -err; 2380 rth->rt_flags &= ~RTCF_LOCAL; 2381 } 2382 hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net)); 2383 rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif); 2384 err = 0; 2385 if (IS_ERR(rth)) 2386 err = PTR_ERR(rth); 2387 goto out; 2388 2389 no_route: 2390 RT_CACHE_STAT_INC(in_no_route); 2391 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE); 2392 res.type = RTN_UNREACHABLE; 2393 if (err == -ESRCH) 2394 err = -ENETUNREACH; 2395 goto local_input; 2396 2397 /* 2398 * Do not cache martian addresses: they should be logged (RFC1812) 2399 */ 2400 martian_destination: 2401 RT_CACHE_STAT_INC(in_martian_dst); 2402 #ifdef CONFIG_IP_ROUTE_VERBOSE 2403 if (IN_DEV_LOG_MARTIANS(in_dev)) 2404 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 2405 &daddr, &saddr, dev->name); 2406 #endif 2407 2408 e_hostunreach: 2409 err = -EHOSTUNREACH; 2410 goto out; 2411 2412 e_inval: 2413 err = -EINVAL; 2414 goto out; 2415 2416 e_nobufs: 2417 err = -ENOBUFS; 2418 goto out; 2419 2420 martian_source: 2421 err = -EINVAL; 2422 martian_source_keep_err: 2423 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2424 goto out; 2425 } 2426 2427 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2428 u8 tos, struct net_device *dev, bool noref) 2429 { 2430 struct rtable *rth; 2431 unsigned int hash; 2432 int iif = dev->ifindex; 2433 struct net *net; 2434 int res; 2435 2436 net = dev_net(dev); 2437 2438 rcu_read_lock(); 2439 2440 if (!rt_caching(net)) 2441 goto skip_cache; 2442 2443 tos &= IPTOS_RT_MASK; 2444 hash = rt_hash(daddr, saddr, iif, rt_genid(net)); 2445 2446 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; 2447 rth = rcu_dereference(rth->dst.rt_next)) { 2448 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) | 2449 ((__force u32)rth->rt_key_src ^ (__force u32)saddr) | 2450 (rth->rt_route_iif ^ iif) | 2451 (rth->rt_key_tos ^ tos)) == 0 && 2452 rth->rt_mark == skb->mark && 2453 net_eq(dev_net(rth->dst.dev), net) && 2454 !rt_is_expired(rth)) { 2455 ipv4_validate_peer(rth); 2456 if (noref) { 2457 dst_use_noref(&rth->dst, jiffies); 2458 skb_dst_set_noref(skb, &rth->dst); 2459 } else { 2460 dst_use(&rth->dst, jiffies); 2461 skb_dst_set(skb, &rth->dst); 2462 } 2463 RT_CACHE_STAT_INC(in_hit); 2464 rcu_read_unlock(); 2465 return 0; 2466 } 2467 RT_CACHE_STAT_INC(in_hlist_search); 2468 } 2469 2470 skip_cache: 2471 /* Multicast recognition logic is moved from route cache to here. 2472 The problem was that too many Ethernet cards have broken/missing 2473 hardware multicast filters :-( As result the host on multicasting 2474 network acquires a lot of useless route cache entries, sort of 2475 SDR messages from all the world. Now we try to get rid of them. 2476 Really, provided software IP multicast filter is organized 2477 reasonably (at least, hashed), it does not result in a slowdown 2478 comparing with route cache reject entries. 2479 Note, that multicast routers are not affected, because 2480 route cache entry is created eventually. 2481 */ 2482 if (ipv4_is_multicast(daddr)) { 2483 struct in_device *in_dev = __in_dev_get_rcu(dev); 2484 2485 if (in_dev) { 2486 int our = ip_check_mc_rcu(in_dev, daddr, saddr, 2487 ip_hdr(skb)->protocol); 2488 if (our 2489 #ifdef CONFIG_IP_MROUTE 2490 || 2491 (!ipv4_is_local_multicast(daddr) && 2492 IN_DEV_MFORWARD(in_dev)) 2493 #endif 2494 ) { 2495 int res = ip_route_input_mc(skb, daddr, saddr, 2496 tos, dev, our); 2497 rcu_read_unlock(); 2498 return res; 2499 } 2500 } 2501 rcu_read_unlock(); 2502 return -EINVAL; 2503 } 2504 res = ip_route_input_slow(skb, daddr, saddr, tos, dev); 2505 rcu_read_unlock(); 2506 return res; 2507 } 2508 EXPORT_SYMBOL(ip_route_input_common); 2509 2510 /* called with rcu_read_lock() */ 2511 static struct rtable *__mkroute_output(const struct fib_result *res, 2512 const struct flowi4 *fl4, 2513 __be32 orig_daddr, __be32 orig_saddr, 2514 int orig_oif, __u8 orig_rtos, 2515 struct net_device *dev_out, 2516 unsigned int flags) 2517 { 2518 struct fib_info *fi = res->fi; 2519 struct in_device *in_dev; 2520 u16 type = res->type; 2521 struct rtable *rth; 2522 2523 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK)) 2524 return ERR_PTR(-EINVAL); 2525 2526 if (ipv4_is_lbcast(fl4->daddr)) 2527 type = RTN_BROADCAST; 2528 else if (ipv4_is_multicast(fl4->daddr)) 2529 type = RTN_MULTICAST; 2530 else if (ipv4_is_zeronet(fl4->daddr)) 2531 return ERR_PTR(-EINVAL); 2532 2533 if (dev_out->flags & IFF_LOOPBACK) 2534 flags |= RTCF_LOCAL; 2535 2536 in_dev = __in_dev_get_rcu(dev_out); 2537 if (!in_dev) 2538 return ERR_PTR(-EINVAL); 2539 2540 if (type == RTN_BROADCAST) { 2541 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2542 fi = NULL; 2543 } else if (type == RTN_MULTICAST) { 2544 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2545 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2546 fl4->flowi4_proto)) 2547 flags &= ~RTCF_LOCAL; 2548 /* If multicast route do not exist use 2549 * default one, but do not gateway in this case. 2550 * Yes, it is hack. 2551 */ 2552 if (fi && res->prefixlen < 4) 2553 fi = NULL; 2554 } 2555 2556 rth = rt_dst_alloc(dev_out, 2557 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2558 IN_DEV_CONF_GET(in_dev, NOXFRM)); 2559 if (!rth) 2560 return ERR_PTR(-ENOBUFS); 2561 2562 rth->dst.output = ip_output; 2563 2564 rth->rt_key_dst = orig_daddr; 2565 rth->rt_key_src = orig_saddr; 2566 rth->rt_genid = rt_genid(dev_net(dev_out)); 2567 rth->rt_flags = flags; 2568 rth->rt_type = type; 2569 rth->rt_key_tos = orig_rtos; 2570 rth->rt_dst = fl4->daddr; 2571 rth->rt_src = fl4->saddr; 2572 rth->rt_route_iif = 0; 2573 rth->rt_iif = orig_oif ? : dev_out->ifindex; 2574 rth->rt_oif = orig_oif; 2575 rth->rt_mark = fl4->flowi4_mark; 2576 rth->rt_gateway = fl4->daddr; 2577 rth->rt_spec_dst= fl4->saddr; 2578 rth->rt_peer_genid = 0; 2579 rth->peer = NULL; 2580 rth->fi = NULL; 2581 2582 RT_CACHE_STAT_INC(out_slow_tot); 2583 2584 if (flags & RTCF_LOCAL) { 2585 rth->dst.input = ip_local_deliver; 2586 rth->rt_spec_dst = fl4->daddr; 2587 } 2588 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2589 rth->rt_spec_dst = fl4->saddr; 2590 if (flags & RTCF_LOCAL && 2591 !(dev_out->flags & IFF_LOOPBACK)) { 2592 rth->dst.output = ip_mc_output; 2593 RT_CACHE_STAT_INC(out_slow_mc); 2594 } 2595 #ifdef CONFIG_IP_MROUTE 2596 if (type == RTN_MULTICAST) { 2597 if (IN_DEV_MFORWARD(in_dev) && 2598 !ipv4_is_local_multicast(fl4->daddr)) { 2599 rth->dst.input = ip_mr_input; 2600 rth->dst.output = ip_mc_output; 2601 } 2602 } 2603 #endif 2604 } 2605 2606 rt_set_nexthop(rth, fl4, res, fi, type, 0); 2607 2608 return rth; 2609 } 2610 2611 /* 2612 * Major route resolver routine. 2613 * called with rcu_read_lock(); 2614 */ 2615 2616 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4) 2617 { 2618 struct net_device *dev_out = NULL; 2619 __u8 tos = RT_FL_TOS(fl4); 2620 unsigned int flags = 0; 2621 struct fib_result res; 2622 struct rtable *rth; 2623 __be32 orig_daddr; 2624 __be32 orig_saddr; 2625 int orig_oif; 2626 2627 res.fi = NULL; 2628 #ifdef CONFIG_IP_MULTIPLE_TABLES 2629 res.r = NULL; 2630 #endif 2631 2632 orig_daddr = fl4->daddr; 2633 orig_saddr = fl4->saddr; 2634 orig_oif = fl4->flowi4_oif; 2635 2636 fl4->flowi4_iif = net->loopback_dev->ifindex; 2637 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2638 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2639 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2640 2641 rcu_read_lock(); 2642 if (fl4->saddr) { 2643 rth = ERR_PTR(-EINVAL); 2644 if (ipv4_is_multicast(fl4->saddr) || 2645 ipv4_is_lbcast(fl4->saddr) || 2646 ipv4_is_zeronet(fl4->saddr)) 2647 goto out; 2648 2649 /* I removed check for oif == dev_out->oif here. 2650 It was wrong for two reasons: 2651 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2652 is assigned to multiple interfaces. 2653 2. Moreover, we are allowed to send packets with saddr 2654 of another iface. --ANK 2655 */ 2656 2657 if (fl4->flowi4_oif == 0 && 2658 (ipv4_is_multicast(fl4->daddr) || 2659 ipv4_is_lbcast(fl4->daddr))) { 2660 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2661 dev_out = __ip_dev_find(net, fl4->saddr, false); 2662 if (dev_out == NULL) 2663 goto out; 2664 2665 /* Special hack: user can direct multicasts 2666 and limited broadcast via necessary interface 2667 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2668 This hack is not just for fun, it allows 2669 vic,vat and friends to work. 2670 They bind socket to loopback, set ttl to zero 2671 and expect that it will work. 2672 From the viewpoint of routing cache they are broken, 2673 because we are not allowed to build multicast path 2674 with loopback source addr (look, routing cache 2675 cannot know, that ttl is zero, so that packet 2676 will not leave this host and route is valid). 2677 Luckily, this hack is good workaround. 2678 */ 2679 2680 fl4->flowi4_oif = dev_out->ifindex; 2681 goto make_route; 2682 } 2683 2684 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2685 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2686 if (!__ip_dev_find(net, fl4->saddr, false)) 2687 goto out; 2688 } 2689 } 2690 2691 2692 if (fl4->flowi4_oif) { 2693 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2694 rth = ERR_PTR(-ENODEV); 2695 if (dev_out == NULL) 2696 goto out; 2697 2698 /* RACE: Check return value of inet_select_addr instead. */ 2699 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2700 rth = ERR_PTR(-ENETUNREACH); 2701 goto out; 2702 } 2703 if (ipv4_is_local_multicast(fl4->daddr) || 2704 ipv4_is_lbcast(fl4->daddr)) { 2705 if (!fl4->saddr) 2706 fl4->saddr = inet_select_addr(dev_out, 0, 2707 RT_SCOPE_LINK); 2708 goto make_route; 2709 } 2710 if (fl4->saddr) { 2711 if (ipv4_is_multicast(fl4->daddr)) 2712 fl4->saddr = inet_select_addr(dev_out, 0, 2713 fl4->flowi4_scope); 2714 else if (!fl4->daddr) 2715 fl4->saddr = inet_select_addr(dev_out, 0, 2716 RT_SCOPE_HOST); 2717 } 2718 } 2719 2720 if (!fl4->daddr) { 2721 fl4->daddr = fl4->saddr; 2722 if (!fl4->daddr) 2723 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2724 dev_out = net->loopback_dev; 2725 fl4->flowi4_oif = net->loopback_dev->ifindex; 2726 res.type = RTN_LOCAL; 2727 flags |= RTCF_LOCAL; 2728 goto make_route; 2729 } 2730 2731 if (fib_lookup(net, fl4, &res)) { 2732 res.fi = NULL; 2733 if (fl4->flowi4_oif) { 2734 /* Apparently, routing tables are wrong. Assume, 2735 that the destination is on link. 2736 2737 WHY? DW. 2738 Because we are allowed to send to iface 2739 even if it has NO routes and NO assigned 2740 addresses. When oif is specified, routing 2741 tables are looked up with only one purpose: 2742 to catch if destination is gatewayed, rather than 2743 direct. Moreover, if MSG_DONTROUTE is set, 2744 we send packet, ignoring both routing tables 2745 and ifaddr state. --ANK 2746 2747 2748 We could make it even if oif is unknown, 2749 likely IPv6, but we do not. 2750 */ 2751 2752 if (fl4->saddr == 0) 2753 fl4->saddr = inet_select_addr(dev_out, 0, 2754 RT_SCOPE_LINK); 2755 res.type = RTN_UNICAST; 2756 goto make_route; 2757 } 2758 rth = ERR_PTR(-ENETUNREACH); 2759 goto out; 2760 } 2761 2762 if (res.type == RTN_LOCAL) { 2763 if (!fl4->saddr) { 2764 if (res.fi->fib_prefsrc) 2765 fl4->saddr = res.fi->fib_prefsrc; 2766 else 2767 fl4->saddr = fl4->daddr; 2768 } 2769 dev_out = net->loopback_dev; 2770 fl4->flowi4_oif = dev_out->ifindex; 2771 res.fi = NULL; 2772 flags |= RTCF_LOCAL; 2773 goto make_route; 2774 } 2775 2776 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2777 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0) 2778 fib_select_multipath(&res); 2779 else 2780 #endif 2781 if (!res.prefixlen && 2782 res.table->tb_num_default > 1 && 2783 res.type == RTN_UNICAST && !fl4->flowi4_oif) 2784 fib_select_default(&res); 2785 2786 if (!fl4->saddr) 2787 fl4->saddr = FIB_RES_PREFSRC(net, res); 2788 2789 dev_out = FIB_RES_DEV(res); 2790 fl4->flowi4_oif = dev_out->ifindex; 2791 2792 2793 make_route: 2794 rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif, 2795 tos, dev_out, flags); 2796 if (!IS_ERR(rth)) { 2797 unsigned int hash; 2798 2799 hash = rt_hash(orig_daddr, orig_saddr, orig_oif, 2800 rt_genid(dev_net(dev_out))); 2801 rth = rt_intern_hash(hash, rth, NULL, orig_oif); 2802 } 2803 2804 out: 2805 rcu_read_unlock(); 2806 return rth; 2807 } 2808 2809 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4) 2810 { 2811 struct rtable *rth; 2812 unsigned int hash; 2813 2814 if (!rt_caching(net)) 2815 goto slow_output; 2816 2817 hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net)); 2818 2819 rcu_read_lock_bh(); 2820 for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth; 2821 rth = rcu_dereference_bh(rth->dst.rt_next)) { 2822 if (rth->rt_key_dst == flp4->daddr && 2823 rth->rt_key_src == flp4->saddr && 2824 rt_is_output_route(rth) && 2825 rth->rt_oif == flp4->flowi4_oif && 2826 rth->rt_mark == flp4->flowi4_mark && 2827 !((rth->rt_key_tos ^ flp4->flowi4_tos) & 2828 (IPTOS_RT_MASK | RTO_ONLINK)) && 2829 net_eq(dev_net(rth->dst.dev), net) && 2830 !rt_is_expired(rth)) { 2831 ipv4_validate_peer(rth); 2832 dst_use(&rth->dst, jiffies); 2833 RT_CACHE_STAT_INC(out_hit); 2834 rcu_read_unlock_bh(); 2835 if (!flp4->saddr) 2836 flp4->saddr = rth->rt_src; 2837 if (!flp4->daddr) 2838 flp4->daddr = rth->rt_dst; 2839 return rth; 2840 } 2841 RT_CACHE_STAT_INC(out_hlist_search); 2842 } 2843 rcu_read_unlock_bh(); 2844 2845 slow_output: 2846 return ip_route_output_slow(net, flp4); 2847 } 2848 EXPORT_SYMBOL_GPL(__ip_route_output_key); 2849 2850 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2851 { 2852 return NULL; 2853 } 2854 2855 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2856 { 2857 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2858 2859 return mtu ? : dst->dev->mtu; 2860 } 2861 2862 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu) 2863 { 2864 } 2865 2866 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2867 unsigned long old) 2868 { 2869 return NULL; 2870 } 2871 2872 static struct dst_ops ipv4_dst_blackhole_ops = { 2873 .family = AF_INET, 2874 .protocol = cpu_to_be16(ETH_P_IP), 2875 .destroy = ipv4_dst_destroy, 2876 .check = ipv4_blackhole_dst_check, 2877 .mtu = ipv4_blackhole_mtu, 2878 .default_advmss = ipv4_default_advmss, 2879 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2880 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2881 .neigh_lookup = ipv4_neigh_lookup, 2882 }; 2883 2884 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2885 { 2886 struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0); 2887 struct rtable *ort = (struct rtable *) dst_orig; 2888 2889 if (rt) { 2890 struct dst_entry *new = &rt->dst; 2891 2892 new->__use = 1; 2893 new->input = dst_discard; 2894 new->output = dst_discard; 2895 dst_copy_metrics(new, &ort->dst); 2896 2897 new->dev = ort->dst.dev; 2898 if (new->dev) 2899 dev_hold(new->dev); 2900 2901 rt->rt_key_dst = ort->rt_key_dst; 2902 rt->rt_key_src = ort->rt_key_src; 2903 rt->rt_key_tos = ort->rt_key_tos; 2904 rt->rt_route_iif = ort->rt_route_iif; 2905 rt->rt_iif = ort->rt_iif; 2906 rt->rt_oif = ort->rt_oif; 2907 rt->rt_mark = ort->rt_mark; 2908 2909 rt->rt_genid = rt_genid(net); 2910 rt->rt_flags = ort->rt_flags; 2911 rt->rt_type = ort->rt_type; 2912 rt->rt_dst = ort->rt_dst; 2913 rt->rt_src = ort->rt_src; 2914 rt->rt_gateway = ort->rt_gateway; 2915 rt->rt_spec_dst = ort->rt_spec_dst; 2916 rt->peer = ort->peer; 2917 if (rt->peer) 2918 atomic_inc(&rt->peer->refcnt); 2919 rt->fi = ort->fi; 2920 if (rt->fi) 2921 atomic_inc(&rt->fi->fib_clntref); 2922 2923 dst_free(new); 2924 } 2925 2926 dst_release(dst_orig); 2927 2928 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2929 } 2930 2931 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2932 struct sock *sk) 2933 { 2934 struct rtable *rt = __ip_route_output_key(net, flp4); 2935 2936 if (IS_ERR(rt)) 2937 return rt; 2938 2939 if (flp4->flowi4_proto) 2940 rt = (struct rtable *) xfrm_lookup(net, &rt->dst, 2941 flowi4_to_flowi(flp4), 2942 sk, 0); 2943 2944 return rt; 2945 } 2946 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2947 2948 static int rt_fill_info(struct net *net, 2949 struct sk_buff *skb, u32 pid, u32 seq, int event, 2950 int nowait, unsigned int flags) 2951 { 2952 struct rtable *rt = skb_rtable(skb); 2953 struct rtmsg *r; 2954 struct nlmsghdr *nlh; 2955 unsigned long expires = 0; 2956 const struct inet_peer *peer = rt->peer; 2957 u32 id = 0, ts = 0, tsage = 0, error; 2958 2959 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags); 2960 if (nlh == NULL) 2961 return -EMSGSIZE; 2962 2963 r = nlmsg_data(nlh); 2964 r->rtm_family = AF_INET; 2965 r->rtm_dst_len = 32; 2966 r->rtm_src_len = 0; 2967 r->rtm_tos = rt->rt_key_tos; 2968 r->rtm_table = RT_TABLE_MAIN; 2969 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN)) 2970 goto nla_put_failure; 2971 r->rtm_type = rt->rt_type; 2972 r->rtm_scope = RT_SCOPE_UNIVERSE; 2973 r->rtm_protocol = RTPROT_UNSPEC; 2974 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2975 if (rt->rt_flags & RTCF_NOTIFY) 2976 r->rtm_flags |= RTM_F_NOTIFY; 2977 2978 if (nla_put_be32(skb, RTA_DST, rt->rt_dst)) 2979 goto nla_put_failure; 2980 if (rt->rt_key_src) { 2981 r->rtm_src_len = 32; 2982 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src)) 2983 goto nla_put_failure; 2984 } 2985 if (rt->dst.dev && 2986 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2987 goto nla_put_failure; 2988 #ifdef CONFIG_IP_ROUTE_CLASSID 2989 if (rt->dst.tclassid && 2990 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2991 goto nla_put_failure; 2992 #endif 2993 if (rt_is_input_route(rt)) { 2994 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_spec_dst)) 2995 goto nla_put_failure; 2996 } else if (rt->rt_src != rt->rt_key_src) { 2997 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src)) 2998 goto nla_put_failure; 2999 } 3000 if (rt->rt_dst != rt->rt_gateway && 3001 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway)) 3002 goto nla_put_failure; 3003 3004 if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0) 3005 goto nla_put_failure; 3006 3007 if (rt->rt_mark && 3008 nla_put_be32(skb, RTA_MARK, rt->rt_mark)) 3009 goto nla_put_failure; 3010 3011 error = rt->dst.error; 3012 if (peer) { 3013 inet_peer_refcheck(rt->peer); 3014 id = atomic_read(&peer->ip_id_count) & 0xffff; 3015 if (peer->tcp_ts_stamp) { 3016 ts = peer->tcp_ts; 3017 tsage = get_seconds() - peer->tcp_ts_stamp; 3018 } 3019 expires = ACCESS_ONCE(peer->pmtu_expires); 3020 if (expires) { 3021 if (time_before(jiffies, expires)) 3022 expires -= jiffies; 3023 else 3024 expires = 0; 3025 } 3026 } 3027 3028 if (rt_is_input_route(rt)) { 3029 #ifdef CONFIG_IP_MROUTE 3030 __be32 dst = rt->rt_dst; 3031 3032 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 3033 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 3034 int err = ipmr_get_route(net, skb, 3035 rt->rt_src, rt->rt_dst, 3036 r, nowait); 3037 if (err <= 0) { 3038 if (!nowait) { 3039 if (err == 0) 3040 return 0; 3041 goto nla_put_failure; 3042 } else { 3043 if (err == -EMSGSIZE) 3044 goto nla_put_failure; 3045 error = err; 3046 } 3047 } 3048 } else 3049 #endif 3050 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif)) 3051 goto nla_put_failure; 3052 } 3053 3054 if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage, 3055 expires, error) < 0) 3056 goto nla_put_failure; 3057 3058 return nlmsg_end(skb, nlh); 3059 3060 nla_put_failure: 3061 nlmsg_cancel(skb, nlh); 3062 return -EMSGSIZE; 3063 } 3064 3065 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg) 3066 { 3067 struct net *net = sock_net(in_skb->sk); 3068 struct rtmsg *rtm; 3069 struct nlattr *tb[RTA_MAX+1]; 3070 struct rtable *rt = NULL; 3071 __be32 dst = 0; 3072 __be32 src = 0; 3073 u32 iif; 3074 int err; 3075 int mark; 3076 struct sk_buff *skb; 3077 3078 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 3079 if (err < 0) 3080 goto errout; 3081 3082 rtm = nlmsg_data(nlh); 3083 3084 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 3085 if (skb == NULL) { 3086 err = -ENOBUFS; 3087 goto errout; 3088 } 3089 3090 /* Reserve room for dummy headers, this skb can pass 3091 through good chunk of routing engine. 3092 */ 3093 skb_reset_mac_header(skb); 3094 skb_reset_network_header(skb); 3095 3096 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 3097 ip_hdr(skb)->protocol = IPPROTO_ICMP; 3098 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 3099 3100 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0; 3101 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0; 3102 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 3103 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 3104 3105 if (iif) { 3106 struct net_device *dev; 3107 3108 dev = __dev_get_by_index(net, iif); 3109 if (dev == NULL) { 3110 err = -ENODEV; 3111 goto errout_free; 3112 } 3113 3114 skb->protocol = htons(ETH_P_IP); 3115 skb->dev = dev; 3116 skb->mark = mark; 3117 local_bh_disable(); 3118 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 3119 local_bh_enable(); 3120 3121 rt = skb_rtable(skb); 3122 if (err == 0 && rt->dst.error) 3123 err = -rt->dst.error; 3124 } else { 3125 struct flowi4 fl4 = { 3126 .daddr = dst, 3127 .saddr = src, 3128 .flowi4_tos = rtm->rtm_tos, 3129 .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0, 3130 .flowi4_mark = mark, 3131 }; 3132 rt = ip_route_output_key(net, &fl4); 3133 3134 err = 0; 3135 if (IS_ERR(rt)) 3136 err = PTR_ERR(rt); 3137 } 3138 3139 if (err) 3140 goto errout_free; 3141 3142 skb_dst_set(skb, &rt->dst); 3143 if (rtm->rtm_flags & RTM_F_NOTIFY) 3144 rt->rt_flags |= RTCF_NOTIFY; 3145 3146 err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 3147 RTM_NEWROUTE, 0, 0); 3148 if (err <= 0) 3149 goto errout_free; 3150 3151 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid); 3152 errout: 3153 return err; 3154 3155 errout_free: 3156 kfree_skb(skb); 3157 goto errout; 3158 } 3159 3160 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) 3161 { 3162 struct rtable *rt; 3163 int h, s_h; 3164 int idx, s_idx; 3165 struct net *net; 3166 3167 net = sock_net(skb->sk); 3168 3169 s_h = cb->args[0]; 3170 if (s_h < 0) 3171 s_h = 0; 3172 s_idx = idx = cb->args[1]; 3173 for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) { 3174 if (!rt_hash_table[h].chain) 3175 continue; 3176 rcu_read_lock_bh(); 3177 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt; 3178 rt = rcu_dereference_bh(rt->dst.rt_next), idx++) { 3179 if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx) 3180 continue; 3181 if (rt_is_expired(rt)) 3182 continue; 3183 skb_dst_set_noref(skb, &rt->dst); 3184 if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid, 3185 cb->nlh->nlmsg_seq, RTM_NEWROUTE, 3186 1, NLM_F_MULTI) <= 0) { 3187 skb_dst_drop(skb); 3188 rcu_read_unlock_bh(); 3189 goto done; 3190 } 3191 skb_dst_drop(skb); 3192 } 3193 rcu_read_unlock_bh(); 3194 } 3195 3196 done: 3197 cb->args[0] = h; 3198 cb->args[1] = idx; 3199 return skb->len; 3200 } 3201 3202 void ip_rt_multicast_event(struct in_device *in_dev) 3203 { 3204 rt_cache_flush(dev_net(in_dev->dev), 0); 3205 } 3206 3207 #ifdef CONFIG_SYSCTL 3208 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write, 3209 void __user *buffer, 3210 size_t *lenp, loff_t *ppos) 3211 { 3212 if (write) { 3213 int flush_delay; 3214 ctl_table ctl; 3215 struct net *net; 3216 3217 memcpy(&ctl, __ctl, sizeof(ctl)); 3218 ctl.data = &flush_delay; 3219 proc_dointvec(&ctl, write, buffer, lenp, ppos); 3220 3221 net = (struct net *)__ctl->extra1; 3222 rt_cache_flush(net, flush_delay); 3223 return 0; 3224 } 3225 3226 return -EINVAL; 3227 } 3228 3229 static ctl_table ipv4_route_table[] = { 3230 { 3231 .procname = "gc_thresh", 3232 .data = &ipv4_dst_ops.gc_thresh, 3233 .maxlen = sizeof(int), 3234 .mode = 0644, 3235 .proc_handler = proc_dointvec, 3236 }, 3237 { 3238 .procname = "max_size", 3239 .data = &ip_rt_max_size, 3240 .maxlen = sizeof(int), 3241 .mode = 0644, 3242 .proc_handler = proc_dointvec, 3243 }, 3244 { 3245 /* Deprecated. Use gc_min_interval_ms */ 3246 3247 .procname = "gc_min_interval", 3248 .data = &ip_rt_gc_min_interval, 3249 .maxlen = sizeof(int), 3250 .mode = 0644, 3251 .proc_handler = proc_dointvec_jiffies, 3252 }, 3253 { 3254 .procname = "gc_min_interval_ms", 3255 .data = &ip_rt_gc_min_interval, 3256 .maxlen = sizeof(int), 3257 .mode = 0644, 3258 .proc_handler = proc_dointvec_ms_jiffies, 3259 }, 3260 { 3261 .procname = "gc_timeout", 3262 .data = &ip_rt_gc_timeout, 3263 .maxlen = sizeof(int), 3264 .mode = 0644, 3265 .proc_handler = proc_dointvec_jiffies, 3266 }, 3267 { 3268 .procname = "gc_interval", 3269 .data = &ip_rt_gc_interval, 3270 .maxlen = sizeof(int), 3271 .mode = 0644, 3272 .proc_handler = proc_dointvec_jiffies, 3273 }, 3274 { 3275 .procname = "redirect_load", 3276 .data = &ip_rt_redirect_load, 3277 .maxlen = sizeof(int), 3278 .mode = 0644, 3279 .proc_handler = proc_dointvec, 3280 }, 3281 { 3282 .procname = "redirect_number", 3283 .data = &ip_rt_redirect_number, 3284 .maxlen = sizeof(int), 3285 .mode = 0644, 3286 .proc_handler = proc_dointvec, 3287 }, 3288 { 3289 .procname = "redirect_silence", 3290 .data = &ip_rt_redirect_silence, 3291 .maxlen = sizeof(int), 3292 .mode = 0644, 3293 .proc_handler = proc_dointvec, 3294 }, 3295 { 3296 .procname = "error_cost", 3297 .data = &ip_rt_error_cost, 3298 .maxlen = sizeof(int), 3299 .mode = 0644, 3300 .proc_handler = proc_dointvec, 3301 }, 3302 { 3303 .procname = "error_burst", 3304 .data = &ip_rt_error_burst, 3305 .maxlen = sizeof(int), 3306 .mode = 0644, 3307 .proc_handler = proc_dointvec, 3308 }, 3309 { 3310 .procname = "gc_elasticity", 3311 .data = &ip_rt_gc_elasticity, 3312 .maxlen = sizeof(int), 3313 .mode = 0644, 3314 .proc_handler = proc_dointvec, 3315 }, 3316 { 3317 .procname = "mtu_expires", 3318 .data = &ip_rt_mtu_expires, 3319 .maxlen = sizeof(int), 3320 .mode = 0644, 3321 .proc_handler = proc_dointvec_jiffies, 3322 }, 3323 { 3324 .procname = "min_pmtu", 3325 .data = &ip_rt_min_pmtu, 3326 .maxlen = sizeof(int), 3327 .mode = 0644, 3328 .proc_handler = proc_dointvec, 3329 }, 3330 { 3331 .procname = "min_adv_mss", 3332 .data = &ip_rt_min_advmss, 3333 .maxlen = sizeof(int), 3334 .mode = 0644, 3335 .proc_handler = proc_dointvec, 3336 }, 3337 { } 3338 }; 3339 3340 static struct ctl_table ipv4_route_flush_table[] = { 3341 { 3342 .procname = "flush", 3343 .maxlen = sizeof(int), 3344 .mode = 0200, 3345 .proc_handler = ipv4_sysctl_rtcache_flush, 3346 }, 3347 { }, 3348 }; 3349 3350 static __net_init int sysctl_route_net_init(struct net *net) 3351 { 3352 struct ctl_table *tbl; 3353 3354 tbl = ipv4_route_flush_table; 3355 if (!net_eq(net, &init_net)) { 3356 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 3357 if (tbl == NULL) 3358 goto err_dup; 3359 } 3360 tbl[0].extra1 = net; 3361 3362 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 3363 if (net->ipv4.route_hdr == NULL) 3364 goto err_reg; 3365 return 0; 3366 3367 err_reg: 3368 if (tbl != ipv4_route_flush_table) 3369 kfree(tbl); 3370 err_dup: 3371 return -ENOMEM; 3372 } 3373 3374 static __net_exit void sysctl_route_net_exit(struct net *net) 3375 { 3376 struct ctl_table *tbl; 3377 3378 tbl = net->ipv4.route_hdr->ctl_table_arg; 3379 unregister_net_sysctl_table(net->ipv4.route_hdr); 3380 BUG_ON(tbl == ipv4_route_flush_table); 3381 kfree(tbl); 3382 } 3383 3384 static __net_initdata struct pernet_operations sysctl_route_ops = { 3385 .init = sysctl_route_net_init, 3386 .exit = sysctl_route_net_exit, 3387 }; 3388 #endif 3389 3390 static __net_init int rt_genid_init(struct net *net) 3391 { 3392 get_random_bytes(&net->ipv4.rt_genid, 3393 sizeof(net->ipv4.rt_genid)); 3394 get_random_bytes(&net->ipv4.dev_addr_genid, 3395 sizeof(net->ipv4.dev_addr_genid)); 3396 return 0; 3397 } 3398 3399 static __net_initdata struct pernet_operations rt_genid_ops = { 3400 .init = rt_genid_init, 3401 }; 3402 3403 3404 #ifdef CONFIG_IP_ROUTE_CLASSID 3405 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 3406 #endif /* CONFIG_IP_ROUTE_CLASSID */ 3407 3408 static __initdata unsigned long rhash_entries; 3409 static int __init set_rhash_entries(char *str) 3410 { 3411 ssize_t ret; 3412 3413 if (!str) 3414 return 0; 3415 3416 ret = kstrtoul(str, 0, &rhash_entries); 3417 if (ret) 3418 return 0; 3419 3420 return 1; 3421 } 3422 __setup("rhash_entries=", set_rhash_entries); 3423 3424 int __init ip_rt_init(void) 3425 { 3426 int rc = 0; 3427 3428 #ifdef CONFIG_IP_ROUTE_CLASSID 3429 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 3430 if (!ip_rt_acct) 3431 panic("IP: failed to allocate ip_rt_acct\n"); 3432 #endif 3433 3434 ipv4_dst_ops.kmem_cachep = 3435 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3436 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3437 3438 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 3439 3440 if (dst_entries_init(&ipv4_dst_ops) < 0) 3441 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 3442 3443 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 3444 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 3445 3446 rt_hash_table = (struct rt_hash_bucket *) 3447 alloc_large_system_hash("IP route cache", 3448 sizeof(struct rt_hash_bucket), 3449 rhash_entries, 3450 (totalram_pages >= 128 * 1024) ? 3451 15 : 17, 3452 0, 3453 &rt_hash_log, 3454 &rt_hash_mask, 3455 0, 3456 rhash_entries ? 0 : 512 * 1024); 3457 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket)); 3458 rt_hash_lock_init(); 3459 3460 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1); 3461 ip_rt_max_size = (rt_hash_mask + 1) * 16; 3462 3463 devinet_init(); 3464 ip_fib_init(); 3465 3466 INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func); 3467 expires_ljiffies = jiffies; 3468 schedule_delayed_work(&expires_work, 3469 net_random() % ip_rt_gc_interval + ip_rt_gc_interval); 3470 3471 if (ip_rt_proc_init()) 3472 pr_err("Unable to create route proc files\n"); 3473 #ifdef CONFIG_XFRM 3474 xfrm_init(); 3475 xfrm4_init(ip_rt_max_size); 3476 #endif 3477 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); 3478 3479 #ifdef CONFIG_SYSCTL 3480 register_pernet_subsys(&sysctl_route_ops); 3481 #endif 3482 register_pernet_subsys(&rt_genid_ops); 3483 return rc; 3484 } 3485 3486 #ifdef CONFIG_SYSCTL 3487 /* 3488 * We really need to sanitize the damn ipv4 init order, then all 3489 * this nonsense will go away. 3490 */ 3491 void __init ip_static_sysctl_init(void) 3492 { 3493 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 3494 } 3495 #endif 3496