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 * Version: $Id: route.c,v 1.103 2002/01/12 07:44:09 davem Exp $ 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Alan Cox, <gw4pts@gw4pts.ampr.org> 13 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 14 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 15 * 16 * Fixes: 17 * Alan Cox : Verify area fixes. 18 * Alan Cox : cli() protects routing changes 19 * Rui Oliveira : ICMP routing table updates 20 * (rco@di.uminho.pt) Routing table insertion and update 21 * Linus Torvalds : Rewrote bits to be sensible 22 * Alan Cox : Added BSD route gw semantics 23 * Alan Cox : Super /proc >4K 24 * Alan Cox : MTU in route table 25 * Alan Cox : MSS actually. Also added the window 26 * clamper. 27 * Sam Lantinga : Fixed route matching in rt_del() 28 * Alan Cox : Routing cache support. 29 * Alan Cox : Removed compatibility cruft. 30 * Alan Cox : RTF_REJECT support. 31 * Alan Cox : TCP irtt support. 32 * Jonathan Naylor : Added Metric support. 33 * Miquel van Smoorenburg : BSD API fixes. 34 * Miquel van Smoorenburg : Metrics. 35 * Alan Cox : Use __u32 properly 36 * Alan Cox : Aligned routing errors more closely with BSD 37 * our system is still very different. 38 * Alan Cox : Faster /proc handling 39 * Alexey Kuznetsov : Massive rework to support tree based routing, 40 * routing caches and better behaviour. 41 * 42 * Olaf Erb : irtt wasn't being copied right. 43 * Bjorn Ekwall : Kerneld route support. 44 * Alan Cox : Multicast fixed (I hope) 45 * Pavel Krauz : Limited broadcast fixed 46 * Mike McLagan : Routing by source 47 * Alexey Kuznetsov : End of old history. Split to fib.c and 48 * route.c and rewritten from scratch. 49 * Andi Kleen : Load-limit warning messages. 50 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 51 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 52 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 53 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 54 * Marc Boucher : routing by fwmark 55 * Robert Olsson : Added rt_cache statistics 56 * Arnaldo C. Melo : Convert proc stuff to seq_file 57 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 58 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 59 * Ilia Sotnikov : Removed TOS from hash calculations 60 * 61 * This program is free software; you can redistribute it and/or 62 * modify it under the terms of the GNU General Public License 63 * as published by the Free Software Foundation; either version 64 * 2 of the License, or (at your option) any later version. 65 */ 66 67 #include <linux/module.h> 68 #include <asm/uaccess.h> 69 #include <asm/system.h> 70 #include <linux/bitops.h> 71 #include <linux/types.h> 72 #include <linux/kernel.h> 73 #include <linux/sched.h> 74 #include <linux/mm.h> 75 #include <linux/bootmem.h> 76 #include <linux/string.h> 77 #include <linux/socket.h> 78 #include <linux/sockios.h> 79 #include <linux/errno.h> 80 #include <linux/in.h> 81 #include <linux/inet.h> 82 #include <linux/netdevice.h> 83 #include <linux/proc_fs.h> 84 #include <linux/init.h> 85 #include <linux/skbuff.h> 86 #include <linux/rtnetlink.h> 87 #include <linux/inetdevice.h> 88 #include <linux/igmp.h> 89 #include <linux/pkt_sched.h> 90 #include <linux/mroute.h> 91 #include <linux/netfilter_ipv4.h> 92 #include <linux/random.h> 93 #include <linux/jhash.h> 94 #include <linux/rcupdate.h> 95 #include <linux/times.h> 96 #include <net/protocol.h> 97 #include <net/ip.h> 98 #include <net/route.h> 99 #include <net/inetpeer.h> 100 #include <net/sock.h> 101 #include <net/ip_fib.h> 102 #include <net/arp.h> 103 #include <net/tcp.h> 104 #include <net/icmp.h> 105 #include <net/xfrm.h> 106 #include <net/ip_mp_alg.h> 107 #include <net/netevent.h> 108 #ifdef CONFIG_SYSCTL 109 #include <linux/sysctl.h> 110 #endif 111 112 #define RT_FL_TOS(oldflp) \ 113 ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK))) 114 115 #define IP_MAX_MTU 0xFFF0 116 117 #define RT_GC_TIMEOUT (300*HZ) 118 119 static int ip_rt_min_delay = 2 * HZ; 120 static int ip_rt_max_delay = 10 * HZ; 121 static int ip_rt_max_size; 122 static int ip_rt_gc_timeout = RT_GC_TIMEOUT; 123 static int ip_rt_gc_interval = 60 * HZ; 124 static int ip_rt_gc_min_interval = HZ / 2; 125 static int ip_rt_redirect_number = 9; 126 static int ip_rt_redirect_load = HZ / 50; 127 static int ip_rt_redirect_silence = ((HZ / 50) << (9 + 1)); 128 static int ip_rt_error_cost = HZ; 129 static int ip_rt_error_burst = 5 * HZ; 130 static int ip_rt_gc_elasticity = 8; 131 static int ip_rt_mtu_expires = 10 * 60 * HZ; 132 static int ip_rt_min_pmtu = 512 + 20 + 20; 133 static int ip_rt_min_advmss = 256; 134 static int ip_rt_secret_interval = 10 * 60 * HZ; 135 static unsigned long rt_deadline; 136 137 #define RTprint(a...) printk(KERN_DEBUG a) 138 139 static struct timer_list rt_flush_timer; 140 static struct timer_list rt_periodic_timer; 141 static struct timer_list rt_secret_timer; 142 143 /* 144 * Interface to generic destination cache. 145 */ 146 147 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 148 static void ipv4_dst_destroy(struct dst_entry *dst); 149 static void ipv4_dst_ifdown(struct dst_entry *dst, 150 struct net_device *dev, int how); 151 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 152 static void ipv4_link_failure(struct sk_buff *skb); 153 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu); 154 static int rt_garbage_collect(void); 155 156 157 static struct dst_ops ipv4_dst_ops = { 158 .family = AF_INET, 159 .protocol = __constant_htons(ETH_P_IP), 160 .gc = rt_garbage_collect, 161 .check = ipv4_dst_check, 162 .destroy = ipv4_dst_destroy, 163 .ifdown = ipv4_dst_ifdown, 164 .negative_advice = ipv4_negative_advice, 165 .link_failure = ipv4_link_failure, 166 .update_pmtu = ip_rt_update_pmtu, 167 .entry_size = sizeof(struct rtable), 168 }; 169 170 #define ECN_OR_COST(class) TC_PRIO_##class 171 172 __u8 ip_tos2prio[16] = { 173 TC_PRIO_BESTEFFORT, 174 ECN_OR_COST(FILLER), 175 TC_PRIO_BESTEFFORT, 176 ECN_OR_COST(BESTEFFORT), 177 TC_PRIO_BULK, 178 ECN_OR_COST(BULK), 179 TC_PRIO_BULK, 180 ECN_OR_COST(BULK), 181 TC_PRIO_INTERACTIVE, 182 ECN_OR_COST(INTERACTIVE), 183 TC_PRIO_INTERACTIVE, 184 ECN_OR_COST(INTERACTIVE), 185 TC_PRIO_INTERACTIVE_BULK, 186 ECN_OR_COST(INTERACTIVE_BULK), 187 TC_PRIO_INTERACTIVE_BULK, 188 ECN_OR_COST(INTERACTIVE_BULK) 189 }; 190 191 192 /* 193 * Route cache. 194 */ 195 196 /* The locking scheme is rather straight forward: 197 * 198 * 1) Read-Copy Update protects the buckets of the central route hash. 199 * 2) Only writers remove entries, and they hold the lock 200 * as they look at rtable reference counts. 201 * 3) Only readers acquire references to rtable entries, 202 * they do so with atomic increments and with the 203 * lock held. 204 */ 205 206 struct rt_hash_bucket { 207 struct rtable *chain; 208 }; 209 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \ 210 defined(CONFIG_PROVE_LOCKING) 211 /* 212 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks 213 * The size of this table is a power of two and depends on the number of CPUS. 214 * (on lockdep we have a quite big spinlock_t, so keep the size down there) 215 */ 216 #ifdef CONFIG_LOCKDEP 217 # define RT_HASH_LOCK_SZ 256 218 #else 219 # if NR_CPUS >= 32 220 # define RT_HASH_LOCK_SZ 4096 221 # elif NR_CPUS >= 16 222 # define RT_HASH_LOCK_SZ 2048 223 # elif NR_CPUS >= 8 224 # define RT_HASH_LOCK_SZ 1024 225 # elif NR_CPUS >= 4 226 # define RT_HASH_LOCK_SZ 512 227 # else 228 # define RT_HASH_LOCK_SZ 256 229 # endif 230 #endif 231 232 static spinlock_t *rt_hash_locks; 233 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)] 234 # define rt_hash_lock_init() { \ 235 int i; \ 236 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ, GFP_KERNEL); \ 237 if (!rt_hash_locks) panic("IP: failed to allocate rt_hash_locks\n"); \ 238 for (i = 0; i < RT_HASH_LOCK_SZ; i++) \ 239 spin_lock_init(&rt_hash_locks[i]); \ 240 } 241 #else 242 # define rt_hash_lock_addr(slot) NULL 243 # define rt_hash_lock_init() 244 #endif 245 246 static struct rt_hash_bucket *rt_hash_table; 247 static unsigned rt_hash_mask; 248 static int rt_hash_log; 249 static unsigned int rt_hash_rnd; 250 251 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 252 #define RT_CACHE_STAT_INC(field) \ 253 (__raw_get_cpu_var(rt_cache_stat).field++) 254 255 static int rt_intern_hash(unsigned hash, struct rtable *rth, 256 struct rtable **res); 257 258 static unsigned int rt_hash_code(u32 daddr, u32 saddr) 259 { 260 return (jhash_2words(daddr, saddr, rt_hash_rnd) 261 & rt_hash_mask); 262 } 263 264 #define rt_hash(daddr, saddr, idx) \ 265 rt_hash_code((__force u32)(__be32)(daddr),\ 266 (__force u32)(__be32)(saddr) ^ ((idx) << 5)) 267 268 #ifdef CONFIG_PROC_FS 269 struct rt_cache_iter_state { 270 int bucket; 271 }; 272 273 static struct rtable *rt_cache_get_first(struct seq_file *seq) 274 { 275 struct rtable *r = NULL; 276 struct rt_cache_iter_state *st = seq->private; 277 278 for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) { 279 rcu_read_lock_bh(); 280 r = rt_hash_table[st->bucket].chain; 281 if (r) 282 break; 283 rcu_read_unlock_bh(); 284 } 285 return r; 286 } 287 288 static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r) 289 { 290 struct rt_cache_iter_state *st = rcu_dereference(seq->private); 291 292 r = r->u.rt_next; 293 while (!r) { 294 rcu_read_unlock_bh(); 295 if (--st->bucket < 0) 296 break; 297 rcu_read_lock_bh(); 298 r = rt_hash_table[st->bucket].chain; 299 } 300 return r; 301 } 302 303 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos) 304 { 305 struct rtable *r = rt_cache_get_first(seq); 306 307 if (r) 308 while (pos && (r = rt_cache_get_next(seq, r))) 309 --pos; 310 return pos ? NULL : r; 311 } 312 313 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 314 { 315 return *pos ? rt_cache_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 316 } 317 318 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 319 { 320 struct rtable *r = NULL; 321 322 if (v == SEQ_START_TOKEN) 323 r = rt_cache_get_first(seq); 324 else 325 r = rt_cache_get_next(seq, v); 326 ++*pos; 327 return r; 328 } 329 330 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 331 { 332 if (v && v != SEQ_START_TOKEN) 333 rcu_read_unlock_bh(); 334 } 335 336 static int rt_cache_seq_show(struct seq_file *seq, void *v) 337 { 338 if (v == SEQ_START_TOKEN) 339 seq_printf(seq, "%-127s\n", 340 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 341 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 342 "HHUptod\tSpecDst"); 343 else { 344 struct rtable *r = v; 345 char temp[256]; 346 347 sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t" 348 "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X", 349 r->u.dst.dev ? r->u.dst.dev->name : "*", 350 (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway, 351 r->rt_flags, atomic_read(&r->u.dst.__refcnt), 352 r->u.dst.__use, 0, (unsigned long)r->rt_src, 353 (dst_metric(&r->u.dst, RTAX_ADVMSS) ? 354 (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0), 355 dst_metric(&r->u.dst, RTAX_WINDOW), 356 (int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) + 357 dst_metric(&r->u.dst, RTAX_RTTVAR)), 358 r->fl.fl4_tos, 359 r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1, 360 r->u.dst.hh ? (r->u.dst.hh->hh_output == 361 dev_queue_xmit) : 0, 362 r->rt_spec_dst); 363 seq_printf(seq, "%-127s\n", temp); 364 } 365 return 0; 366 } 367 368 static struct seq_operations rt_cache_seq_ops = { 369 .start = rt_cache_seq_start, 370 .next = rt_cache_seq_next, 371 .stop = rt_cache_seq_stop, 372 .show = rt_cache_seq_show, 373 }; 374 375 static int rt_cache_seq_open(struct inode *inode, struct file *file) 376 { 377 struct seq_file *seq; 378 int rc = -ENOMEM; 379 struct rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL); 380 381 if (!s) 382 goto out; 383 rc = seq_open(file, &rt_cache_seq_ops); 384 if (rc) 385 goto out_kfree; 386 seq = file->private_data; 387 seq->private = s; 388 memset(s, 0, sizeof(*s)); 389 out: 390 return rc; 391 out_kfree: 392 kfree(s); 393 goto out; 394 } 395 396 static struct file_operations rt_cache_seq_fops = { 397 .owner = THIS_MODULE, 398 .open = rt_cache_seq_open, 399 .read = seq_read, 400 .llseek = seq_lseek, 401 .release = seq_release_private, 402 }; 403 404 405 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 406 { 407 int cpu; 408 409 if (*pos == 0) 410 return SEQ_START_TOKEN; 411 412 for (cpu = *pos-1; cpu < NR_CPUS; ++cpu) { 413 if (!cpu_possible(cpu)) 414 continue; 415 *pos = cpu+1; 416 return &per_cpu(rt_cache_stat, cpu); 417 } 418 return NULL; 419 } 420 421 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 422 { 423 int cpu; 424 425 for (cpu = *pos; cpu < NR_CPUS; ++cpu) { 426 if (!cpu_possible(cpu)) 427 continue; 428 *pos = cpu+1; 429 return &per_cpu(rt_cache_stat, cpu); 430 } 431 return NULL; 432 433 } 434 435 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 436 { 437 438 } 439 440 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 441 { 442 struct rt_cache_stat *st = v; 443 444 if (v == SEQ_START_TOKEN) { 445 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"); 446 return 0; 447 } 448 449 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 450 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 451 atomic_read(&ipv4_dst_ops.entries), 452 st->in_hit, 453 st->in_slow_tot, 454 st->in_slow_mc, 455 st->in_no_route, 456 st->in_brd, 457 st->in_martian_dst, 458 st->in_martian_src, 459 460 st->out_hit, 461 st->out_slow_tot, 462 st->out_slow_mc, 463 464 st->gc_total, 465 st->gc_ignored, 466 st->gc_goal_miss, 467 st->gc_dst_overflow, 468 st->in_hlist_search, 469 st->out_hlist_search 470 ); 471 return 0; 472 } 473 474 static struct seq_operations rt_cpu_seq_ops = { 475 .start = rt_cpu_seq_start, 476 .next = rt_cpu_seq_next, 477 .stop = rt_cpu_seq_stop, 478 .show = rt_cpu_seq_show, 479 }; 480 481 482 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 483 { 484 return seq_open(file, &rt_cpu_seq_ops); 485 } 486 487 static struct file_operations rt_cpu_seq_fops = { 488 .owner = THIS_MODULE, 489 .open = rt_cpu_seq_open, 490 .read = seq_read, 491 .llseek = seq_lseek, 492 .release = seq_release, 493 }; 494 495 #endif /* CONFIG_PROC_FS */ 496 497 static __inline__ void rt_free(struct rtable *rt) 498 { 499 multipath_remove(rt); 500 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free); 501 } 502 503 static __inline__ void rt_drop(struct rtable *rt) 504 { 505 multipath_remove(rt); 506 ip_rt_put(rt); 507 call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free); 508 } 509 510 static __inline__ int rt_fast_clean(struct rtable *rth) 511 { 512 /* Kill broadcast/multicast entries very aggresively, if they 513 collide in hash table with more useful entries */ 514 return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) && 515 rth->fl.iif && rth->u.rt_next; 516 } 517 518 static __inline__ int rt_valuable(struct rtable *rth) 519 { 520 return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) || 521 rth->u.dst.expires; 522 } 523 524 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2) 525 { 526 unsigned long age; 527 int ret = 0; 528 529 if (atomic_read(&rth->u.dst.__refcnt)) 530 goto out; 531 532 ret = 1; 533 if (rth->u.dst.expires && 534 time_after_eq(jiffies, rth->u.dst.expires)) 535 goto out; 536 537 age = jiffies - rth->u.dst.lastuse; 538 ret = 0; 539 if ((age <= tmo1 && !rt_fast_clean(rth)) || 540 (age <= tmo2 && rt_valuable(rth))) 541 goto out; 542 ret = 1; 543 out: return ret; 544 } 545 546 /* Bits of score are: 547 * 31: very valuable 548 * 30: not quite useless 549 * 29..0: usage counter 550 */ 551 static inline u32 rt_score(struct rtable *rt) 552 { 553 u32 score = jiffies - rt->u.dst.lastuse; 554 555 score = ~score & ~(3<<30); 556 557 if (rt_valuable(rt)) 558 score |= (1<<31); 559 560 if (!rt->fl.iif || 561 !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL))) 562 score |= (1<<30); 563 564 return score; 565 } 566 567 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2) 568 { 569 return ((__force u32)((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) | 570 (fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr)) | 571 (fl1->mark ^ fl2->mark) | 572 (*(u16 *)&fl1->nl_u.ip4_u.tos ^ 573 *(u16 *)&fl2->nl_u.ip4_u.tos) | 574 (fl1->oif ^ fl2->oif) | 575 (fl1->iif ^ fl2->iif)) == 0; 576 } 577 578 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 579 static struct rtable **rt_remove_balanced_route(struct rtable **chain_head, 580 struct rtable *expentry, 581 int *removed_count) 582 { 583 int passedexpired = 0; 584 struct rtable **nextstep = NULL; 585 struct rtable **rthp = chain_head; 586 struct rtable *rth; 587 588 if (removed_count) 589 *removed_count = 0; 590 591 while ((rth = *rthp) != NULL) { 592 if (rth == expentry) 593 passedexpired = 1; 594 595 if (((*rthp)->u.dst.flags & DST_BALANCED) != 0 && 596 compare_keys(&(*rthp)->fl, &expentry->fl)) { 597 if (*rthp == expentry) { 598 *rthp = rth->u.rt_next; 599 continue; 600 } else { 601 *rthp = rth->u.rt_next; 602 rt_free(rth); 603 if (removed_count) 604 ++(*removed_count); 605 } 606 } else { 607 if (!((*rthp)->u.dst.flags & DST_BALANCED) && 608 passedexpired && !nextstep) 609 nextstep = &rth->u.rt_next; 610 611 rthp = &rth->u.rt_next; 612 } 613 } 614 615 rt_free(expentry); 616 if (removed_count) 617 ++(*removed_count); 618 619 return nextstep; 620 } 621 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 622 623 624 /* This runs via a timer and thus is always in BH context. */ 625 static void rt_check_expire(unsigned long dummy) 626 { 627 static unsigned int rover; 628 unsigned int i = rover, goal; 629 struct rtable *rth, **rthp; 630 unsigned long now = jiffies; 631 u64 mult; 632 633 mult = ((u64)ip_rt_gc_interval) << rt_hash_log; 634 if (ip_rt_gc_timeout > 1) 635 do_div(mult, ip_rt_gc_timeout); 636 goal = (unsigned int)mult; 637 if (goal > rt_hash_mask) goal = rt_hash_mask + 1; 638 for (; goal > 0; goal--) { 639 unsigned long tmo = ip_rt_gc_timeout; 640 641 i = (i + 1) & rt_hash_mask; 642 rthp = &rt_hash_table[i].chain; 643 644 if (*rthp == 0) 645 continue; 646 spin_lock(rt_hash_lock_addr(i)); 647 while ((rth = *rthp) != NULL) { 648 if (rth->u.dst.expires) { 649 /* Entry is expired even if it is in use */ 650 if (time_before_eq(now, rth->u.dst.expires)) { 651 tmo >>= 1; 652 rthp = &rth->u.rt_next; 653 continue; 654 } 655 } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) { 656 tmo >>= 1; 657 rthp = &rth->u.rt_next; 658 continue; 659 } 660 661 /* Cleanup aged off entries. */ 662 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 663 /* remove all related balanced entries if necessary */ 664 if (rth->u.dst.flags & DST_BALANCED) { 665 rthp = rt_remove_balanced_route( 666 &rt_hash_table[i].chain, 667 rth, NULL); 668 if (!rthp) 669 break; 670 } else { 671 *rthp = rth->u.rt_next; 672 rt_free(rth); 673 } 674 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 675 *rthp = rth->u.rt_next; 676 rt_free(rth); 677 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 678 } 679 spin_unlock(rt_hash_lock_addr(i)); 680 681 /* Fallback loop breaker. */ 682 if (time_after(jiffies, now)) 683 break; 684 } 685 rover = i; 686 mod_timer(&rt_periodic_timer, jiffies + ip_rt_gc_interval); 687 } 688 689 /* This can run from both BH and non-BH contexts, the latter 690 * in the case of a forced flush event. 691 */ 692 static void rt_run_flush(unsigned long dummy) 693 { 694 int i; 695 struct rtable *rth, *next; 696 697 rt_deadline = 0; 698 699 get_random_bytes(&rt_hash_rnd, 4); 700 701 for (i = rt_hash_mask; i >= 0; i--) { 702 spin_lock_bh(rt_hash_lock_addr(i)); 703 rth = rt_hash_table[i].chain; 704 if (rth) 705 rt_hash_table[i].chain = NULL; 706 spin_unlock_bh(rt_hash_lock_addr(i)); 707 708 for (; rth; rth = next) { 709 next = rth->u.rt_next; 710 rt_free(rth); 711 } 712 } 713 } 714 715 static DEFINE_SPINLOCK(rt_flush_lock); 716 717 void rt_cache_flush(int delay) 718 { 719 unsigned long now = jiffies; 720 int user_mode = !in_softirq(); 721 722 if (delay < 0) 723 delay = ip_rt_min_delay; 724 725 /* flush existing multipath state*/ 726 multipath_flush(); 727 728 spin_lock_bh(&rt_flush_lock); 729 730 if (del_timer(&rt_flush_timer) && delay > 0 && rt_deadline) { 731 long tmo = (long)(rt_deadline - now); 732 733 /* If flush timer is already running 734 and flush request is not immediate (delay > 0): 735 736 if deadline is not achieved, prolongate timer to "delay", 737 otherwise fire it at deadline time. 738 */ 739 740 if (user_mode && tmo < ip_rt_max_delay-ip_rt_min_delay) 741 tmo = 0; 742 743 if (delay > tmo) 744 delay = tmo; 745 } 746 747 if (delay <= 0) { 748 spin_unlock_bh(&rt_flush_lock); 749 rt_run_flush(0); 750 return; 751 } 752 753 if (rt_deadline == 0) 754 rt_deadline = now + ip_rt_max_delay; 755 756 mod_timer(&rt_flush_timer, now+delay); 757 spin_unlock_bh(&rt_flush_lock); 758 } 759 760 static void rt_secret_rebuild(unsigned long dummy) 761 { 762 unsigned long now = jiffies; 763 764 rt_cache_flush(0); 765 mod_timer(&rt_secret_timer, now + ip_rt_secret_interval); 766 } 767 768 /* 769 Short description of GC goals. 770 771 We want to build algorithm, which will keep routing cache 772 at some equilibrium point, when number of aged off entries 773 is kept approximately equal to newly generated ones. 774 775 Current expiration strength is variable "expire". 776 We try to adjust it dynamically, so that if networking 777 is idle expires is large enough to keep enough of warm entries, 778 and when load increases it reduces to limit cache size. 779 */ 780 781 static int rt_garbage_collect(void) 782 { 783 static unsigned long expire = RT_GC_TIMEOUT; 784 static unsigned long last_gc; 785 static int rover; 786 static int equilibrium; 787 struct rtable *rth, **rthp; 788 unsigned long now = jiffies; 789 int goal; 790 791 /* 792 * Garbage collection is pretty expensive, 793 * do not make it too frequently. 794 */ 795 796 RT_CACHE_STAT_INC(gc_total); 797 798 if (now - last_gc < ip_rt_gc_min_interval && 799 atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) { 800 RT_CACHE_STAT_INC(gc_ignored); 801 goto out; 802 } 803 804 /* Calculate number of entries, which we want to expire now. */ 805 goal = atomic_read(&ipv4_dst_ops.entries) - 806 (ip_rt_gc_elasticity << rt_hash_log); 807 if (goal <= 0) { 808 if (equilibrium < ipv4_dst_ops.gc_thresh) 809 equilibrium = ipv4_dst_ops.gc_thresh; 810 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium; 811 if (goal > 0) { 812 equilibrium += min_t(unsigned int, goal / 2, rt_hash_mask + 1); 813 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium; 814 } 815 } else { 816 /* We are in dangerous area. Try to reduce cache really 817 * aggressively. 818 */ 819 goal = max_t(unsigned int, goal / 2, rt_hash_mask + 1); 820 equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal; 821 } 822 823 if (now - last_gc >= ip_rt_gc_min_interval) 824 last_gc = now; 825 826 if (goal <= 0) { 827 equilibrium += goal; 828 goto work_done; 829 } 830 831 do { 832 int i, k; 833 834 for (i = rt_hash_mask, k = rover; i >= 0; i--) { 835 unsigned long tmo = expire; 836 837 k = (k + 1) & rt_hash_mask; 838 rthp = &rt_hash_table[k].chain; 839 spin_lock_bh(rt_hash_lock_addr(k)); 840 while ((rth = *rthp) != NULL) { 841 if (!rt_may_expire(rth, tmo, expire)) { 842 tmo >>= 1; 843 rthp = &rth->u.rt_next; 844 continue; 845 } 846 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 847 /* remove all related balanced entries 848 * if necessary 849 */ 850 if (rth->u.dst.flags & DST_BALANCED) { 851 int r; 852 853 rthp = rt_remove_balanced_route( 854 &rt_hash_table[k].chain, 855 rth, 856 &r); 857 goal -= r; 858 if (!rthp) 859 break; 860 } else { 861 *rthp = rth->u.rt_next; 862 rt_free(rth); 863 goal--; 864 } 865 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 866 *rthp = rth->u.rt_next; 867 rt_free(rth); 868 goal--; 869 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 870 } 871 spin_unlock_bh(rt_hash_lock_addr(k)); 872 if (goal <= 0) 873 break; 874 } 875 rover = k; 876 877 if (goal <= 0) 878 goto work_done; 879 880 /* Goal is not achieved. We stop process if: 881 882 - if expire reduced to zero. Otherwise, expire is halfed. 883 - if table is not full. 884 - if we are called from interrupt. 885 - jiffies check is just fallback/debug loop breaker. 886 We will not spin here for long time in any case. 887 */ 888 889 RT_CACHE_STAT_INC(gc_goal_miss); 890 891 if (expire == 0) 892 break; 893 894 expire >>= 1; 895 #if RT_CACHE_DEBUG >= 2 896 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire, 897 atomic_read(&ipv4_dst_ops.entries), goal, i); 898 #endif 899 900 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) 901 goto out; 902 } while (!in_softirq() && time_before_eq(jiffies, now)); 903 904 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) 905 goto out; 906 if (net_ratelimit()) 907 printk(KERN_WARNING "dst cache overflow\n"); 908 RT_CACHE_STAT_INC(gc_dst_overflow); 909 return 1; 910 911 work_done: 912 expire += ip_rt_gc_min_interval; 913 if (expire > ip_rt_gc_timeout || 914 atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh) 915 expire = ip_rt_gc_timeout; 916 #if RT_CACHE_DEBUG >= 2 917 printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire, 918 atomic_read(&ipv4_dst_ops.entries), goal, rover); 919 #endif 920 out: return 0; 921 } 922 923 static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp) 924 { 925 struct rtable *rth, **rthp; 926 unsigned long now; 927 struct rtable *cand, **candp; 928 u32 min_score; 929 int chain_length; 930 int attempts = !in_softirq(); 931 932 restart: 933 chain_length = 0; 934 min_score = ~(u32)0; 935 cand = NULL; 936 candp = NULL; 937 now = jiffies; 938 939 rthp = &rt_hash_table[hash].chain; 940 941 spin_lock_bh(rt_hash_lock_addr(hash)); 942 while ((rth = *rthp) != NULL) { 943 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 944 if (!(rth->u.dst.flags & DST_BALANCED) && 945 compare_keys(&rth->fl, &rt->fl)) { 946 #else 947 if (compare_keys(&rth->fl, &rt->fl)) { 948 #endif 949 /* Put it first */ 950 *rthp = rth->u.rt_next; 951 /* 952 * Since lookup is lockfree, the deletion 953 * must be visible to another weakly ordered CPU before 954 * the insertion at the start of the hash chain. 955 */ 956 rcu_assign_pointer(rth->u.rt_next, 957 rt_hash_table[hash].chain); 958 /* 959 * Since lookup is lockfree, the update writes 960 * must be ordered for consistency on SMP. 961 */ 962 rcu_assign_pointer(rt_hash_table[hash].chain, rth); 963 964 rth->u.dst.__use++; 965 dst_hold(&rth->u.dst); 966 rth->u.dst.lastuse = now; 967 spin_unlock_bh(rt_hash_lock_addr(hash)); 968 969 rt_drop(rt); 970 *rp = rth; 971 return 0; 972 } 973 974 if (!atomic_read(&rth->u.dst.__refcnt)) { 975 u32 score = rt_score(rth); 976 977 if (score <= min_score) { 978 cand = rth; 979 candp = rthp; 980 min_score = score; 981 } 982 } 983 984 chain_length++; 985 986 rthp = &rth->u.rt_next; 987 } 988 989 if (cand) { 990 /* ip_rt_gc_elasticity used to be average length of chain 991 * length, when exceeded gc becomes really aggressive. 992 * 993 * The second limit is less certain. At the moment it allows 994 * only 2 entries per bucket. We will see. 995 */ 996 if (chain_length > ip_rt_gc_elasticity) { 997 *candp = cand->u.rt_next; 998 rt_free(cand); 999 } 1000 } 1001 1002 /* Try to bind route to arp only if it is output 1003 route or unicast forwarding path. 1004 */ 1005 if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) { 1006 int err = arp_bind_neighbour(&rt->u.dst); 1007 if (err) { 1008 spin_unlock_bh(rt_hash_lock_addr(hash)); 1009 1010 if (err != -ENOBUFS) { 1011 rt_drop(rt); 1012 return err; 1013 } 1014 1015 /* Neighbour tables are full and nothing 1016 can be released. Try to shrink route cache, 1017 it is most likely it holds some neighbour records. 1018 */ 1019 if (attempts-- > 0) { 1020 int saved_elasticity = ip_rt_gc_elasticity; 1021 int saved_int = ip_rt_gc_min_interval; 1022 ip_rt_gc_elasticity = 1; 1023 ip_rt_gc_min_interval = 0; 1024 rt_garbage_collect(); 1025 ip_rt_gc_min_interval = saved_int; 1026 ip_rt_gc_elasticity = saved_elasticity; 1027 goto restart; 1028 } 1029 1030 if (net_ratelimit()) 1031 printk(KERN_WARNING "Neighbour table overflow.\n"); 1032 rt_drop(rt); 1033 return -ENOBUFS; 1034 } 1035 } 1036 1037 rt->u.rt_next = rt_hash_table[hash].chain; 1038 #if RT_CACHE_DEBUG >= 2 1039 if (rt->u.rt_next) { 1040 struct rtable *trt; 1041 printk(KERN_DEBUG "rt_cache @%02x: %u.%u.%u.%u", hash, 1042 NIPQUAD(rt->rt_dst)); 1043 for (trt = rt->u.rt_next; trt; trt = trt->u.rt_next) 1044 printk(" . %u.%u.%u.%u", NIPQUAD(trt->rt_dst)); 1045 printk("\n"); 1046 } 1047 #endif 1048 rt_hash_table[hash].chain = rt; 1049 spin_unlock_bh(rt_hash_lock_addr(hash)); 1050 *rp = rt; 1051 return 0; 1052 } 1053 1054 void rt_bind_peer(struct rtable *rt, int create) 1055 { 1056 static DEFINE_SPINLOCK(rt_peer_lock); 1057 struct inet_peer *peer; 1058 1059 peer = inet_getpeer(rt->rt_dst, create); 1060 1061 spin_lock_bh(&rt_peer_lock); 1062 if (rt->peer == NULL) { 1063 rt->peer = peer; 1064 peer = NULL; 1065 } 1066 spin_unlock_bh(&rt_peer_lock); 1067 if (peer) 1068 inet_putpeer(peer); 1069 } 1070 1071 /* 1072 * Peer allocation may fail only in serious out-of-memory conditions. However 1073 * we still can generate some output. 1074 * Random ID selection looks a bit dangerous because we have no chances to 1075 * select ID being unique in a reasonable period of time. 1076 * But broken packet identifier may be better than no packet at all. 1077 */ 1078 static void ip_select_fb_ident(struct iphdr *iph) 1079 { 1080 static DEFINE_SPINLOCK(ip_fb_id_lock); 1081 static u32 ip_fallback_id; 1082 u32 salt; 1083 1084 spin_lock_bh(&ip_fb_id_lock); 1085 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr); 1086 iph->id = htons(salt & 0xFFFF); 1087 ip_fallback_id = salt; 1088 spin_unlock_bh(&ip_fb_id_lock); 1089 } 1090 1091 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more) 1092 { 1093 struct rtable *rt = (struct rtable *) dst; 1094 1095 if (rt) { 1096 if (rt->peer == NULL) 1097 rt_bind_peer(rt, 1); 1098 1099 /* If peer is attached to destination, it is never detached, 1100 so that we need not to grab a lock to dereference it. 1101 */ 1102 if (rt->peer) { 1103 iph->id = htons(inet_getid(rt->peer, more)); 1104 return; 1105 } 1106 } else 1107 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n", 1108 __builtin_return_address(0)); 1109 1110 ip_select_fb_ident(iph); 1111 } 1112 1113 static void rt_del(unsigned hash, struct rtable *rt) 1114 { 1115 struct rtable **rthp; 1116 1117 spin_lock_bh(rt_hash_lock_addr(hash)); 1118 ip_rt_put(rt); 1119 for (rthp = &rt_hash_table[hash].chain; *rthp; 1120 rthp = &(*rthp)->u.rt_next) 1121 if (*rthp == rt) { 1122 *rthp = rt->u.rt_next; 1123 rt_free(rt); 1124 break; 1125 } 1126 spin_unlock_bh(rt_hash_lock_addr(hash)); 1127 } 1128 1129 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, 1130 __be32 saddr, struct net_device *dev) 1131 { 1132 int i, k; 1133 struct in_device *in_dev = in_dev_get(dev); 1134 struct rtable *rth, **rthp; 1135 __be32 skeys[2] = { saddr, 0 }; 1136 int ikeys[2] = { dev->ifindex, 0 }; 1137 struct netevent_redirect netevent; 1138 1139 if (!in_dev) 1140 return; 1141 1142 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) 1143 || MULTICAST(new_gw) || BADCLASS(new_gw) || ZERONET(new_gw)) 1144 goto reject_redirect; 1145 1146 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 1147 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 1148 goto reject_redirect; 1149 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 1150 goto reject_redirect; 1151 } else { 1152 if (inet_addr_type(new_gw) != RTN_UNICAST) 1153 goto reject_redirect; 1154 } 1155 1156 for (i = 0; i < 2; i++) { 1157 for (k = 0; k < 2; k++) { 1158 unsigned hash = rt_hash(daddr, skeys[i], ikeys[k]); 1159 1160 rthp=&rt_hash_table[hash].chain; 1161 1162 rcu_read_lock(); 1163 while ((rth = rcu_dereference(*rthp)) != NULL) { 1164 struct rtable *rt; 1165 1166 if (rth->fl.fl4_dst != daddr || 1167 rth->fl.fl4_src != skeys[i] || 1168 rth->fl.oif != ikeys[k] || 1169 rth->fl.iif != 0) { 1170 rthp = &rth->u.rt_next; 1171 continue; 1172 } 1173 1174 if (rth->rt_dst != daddr || 1175 rth->rt_src != saddr || 1176 rth->u.dst.error || 1177 rth->rt_gateway != old_gw || 1178 rth->u.dst.dev != dev) 1179 break; 1180 1181 dst_hold(&rth->u.dst); 1182 rcu_read_unlock(); 1183 1184 rt = dst_alloc(&ipv4_dst_ops); 1185 if (rt == NULL) { 1186 ip_rt_put(rth); 1187 in_dev_put(in_dev); 1188 return; 1189 } 1190 1191 /* Copy all the information. */ 1192 *rt = *rth; 1193 INIT_RCU_HEAD(&rt->u.dst.rcu_head); 1194 rt->u.dst.__use = 1; 1195 atomic_set(&rt->u.dst.__refcnt, 1); 1196 rt->u.dst.child = NULL; 1197 if (rt->u.dst.dev) 1198 dev_hold(rt->u.dst.dev); 1199 if (rt->idev) 1200 in_dev_hold(rt->idev); 1201 rt->u.dst.obsolete = 0; 1202 rt->u.dst.lastuse = jiffies; 1203 rt->u.dst.path = &rt->u.dst; 1204 rt->u.dst.neighbour = NULL; 1205 rt->u.dst.hh = NULL; 1206 rt->u.dst.xfrm = NULL; 1207 1208 rt->rt_flags |= RTCF_REDIRECTED; 1209 1210 /* Gateway is different ... */ 1211 rt->rt_gateway = new_gw; 1212 1213 /* Redirect received -> path was valid */ 1214 dst_confirm(&rth->u.dst); 1215 1216 if (rt->peer) 1217 atomic_inc(&rt->peer->refcnt); 1218 1219 if (arp_bind_neighbour(&rt->u.dst) || 1220 !(rt->u.dst.neighbour->nud_state & 1221 NUD_VALID)) { 1222 if (rt->u.dst.neighbour) 1223 neigh_event_send(rt->u.dst.neighbour, NULL); 1224 ip_rt_put(rth); 1225 rt_drop(rt); 1226 goto do_next; 1227 } 1228 1229 netevent.old = &rth->u.dst; 1230 netevent.new = &rt->u.dst; 1231 call_netevent_notifiers(NETEVENT_REDIRECT, 1232 &netevent); 1233 1234 rt_del(hash, rth); 1235 if (!rt_intern_hash(hash, rt, &rt)) 1236 ip_rt_put(rt); 1237 goto do_next; 1238 } 1239 rcu_read_unlock(); 1240 do_next: 1241 ; 1242 } 1243 } 1244 in_dev_put(in_dev); 1245 return; 1246 1247 reject_redirect: 1248 #ifdef CONFIG_IP_ROUTE_VERBOSE 1249 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) 1250 printk(KERN_INFO "Redirect from %u.%u.%u.%u on %s about " 1251 "%u.%u.%u.%u ignored.\n" 1252 " Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n", 1253 NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw), 1254 NIPQUAD(saddr), NIPQUAD(daddr)); 1255 #endif 1256 in_dev_put(in_dev); 1257 } 1258 1259 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 1260 { 1261 struct rtable *rt = (struct rtable*)dst; 1262 struct dst_entry *ret = dst; 1263 1264 if (rt) { 1265 if (dst->obsolete) { 1266 ip_rt_put(rt); 1267 ret = NULL; 1268 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 1269 rt->u.dst.expires) { 1270 unsigned hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src, 1271 rt->fl.oif); 1272 #if RT_CACHE_DEBUG >= 1 1273 printk(KERN_DEBUG "ip_rt_advice: redirect to " 1274 "%u.%u.%u.%u/%02x dropped\n", 1275 NIPQUAD(rt->rt_dst), rt->fl.fl4_tos); 1276 #endif 1277 rt_del(hash, rt); 1278 ret = NULL; 1279 } 1280 } 1281 return ret; 1282 } 1283 1284 /* 1285 * Algorithm: 1286 * 1. The first ip_rt_redirect_number redirects are sent 1287 * with exponential backoff, then we stop sending them at all, 1288 * assuming that the host ignores our redirects. 1289 * 2. If we did not see packets requiring redirects 1290 * during ip_rt_redirect_silence, we assume that the host 1291 * forgot redirected route and start to send redirects again. 1292 * 1293 * This algorithm is much cheaper and more intelligent than dumb load limiting 1294 * in icmp.c. 1295 * 1296 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 1297 * and "frag. need" (breaks PMTU discovery) in icmp.c. 1298 */ 1299 1300 void ip_rt_send_redirect(struct sk_buff *skb) 1301 { 1302 struct rtable *rt = (struct rtable*)skb->dst; 1303 struct in_device *in_dev = in_dev_get(rt->u.dst.dev); 1304 1305 if (!in_dev) 1306 return; 1307 1308 if (!IN_DEV_TX_REDIRECTS(in_dev)) 1309 goto out; 1310 1311 /* No redirected packets during ip_rt_redirect_silence; 1312 * reset the algorithm. 1313 */ 1314 if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence)) 1315 rt->u.dst.rate_tokens = 0; 1316 1317 /* Too many ignored redirects; do not send anything 1318 * set u.dst.rate_last to the last seen redirected packet. 1319 */ 1320 if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) { 1321 rt->u.dst.rate_last = jiffies; 1322 goto out; 1323 } 1324 1325 /* Check for load limit; set rate_last to the latest sent 1326 * redirect. 1327 */ 1328 if (time_after(jiffies, 1329 (rt->u.dst.rate_last + 1330 (ip_rt_redirect_load << rt->u.dst.rate_tokens)))) { 1331 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); 1332 rt->u.dst.rate_last = jiffies; 1333 ++rt->u.dst.rate_tokens; 1334 #ifdef CONFIG_IP_ROUTE_VERBOSE 1335 if (IN_DEV_LOG_MARTIANS(in_dev) && 1336 rt->u.dst.rate_tokens == ip_rt_redirect_number && 1337 net_ratelimit()) 1338 printk(KERN_WARNING "host %u.%u.%u.%u/if%d ignores " 1339 "redirects for %u.%u.%u.%u to %u.%u.%u.%u.\n", 1340 NIPQUAD(rt->rt_src), rt->rt_iif, 1341 NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_gateway)); 1342 #endif 1343 } 1344 out: 1345 in_dev_put(in_dev); 1346 } 1347 1348 static int ip_error(struct sk_buff *skb) 1349 { 1350 struct rtable *rt = (struct rtable*)skb->dst; 1351 unsigned long now; 1352 int code; 1353 1354 switch (rt->u.dst.error) { 1355 case EINVAL: 1356 default: 1357 goto out; 1358 case EHOSTUNREACH: 1359 code = ICMP_HOST_UNREACH; 1360 break; 1361 case ENETUNREACH: 1362 code = ICMP_NET_UNREACH; 1363 break; 1364 case EACCES: 1365 code = ICMP_PKT_FILTERED; 1366 break; 1367 } 1368 1369 now = jiffies; 1370 rt->u.dst.rate_tokens += now - rt->u.dst.rate_last; 1371 if (rt->u.dst.rate_tokens > ip_rt_error_burst) 1372 rt->u.dst.rate_tokens = ip_rt_error_burst; 1373 rt->u.dst.rate_last = now; 1374 if (rt->u.dst.rate_tokens >= ip_rt_error_cost) { 1375 rt->u.dst.rate_tokens -= ip_rt_error_cost; 1376 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 1377 } 1378 1379 out: kfree_skb(skb); 1380 return 0; 1381 } 1382 1383 /* 1384 * The last two values are not from the RFC but 1385 * are needed for AMPRnet AX.25 paths. 1386 */ 1387 1388 static const unsigned short mtu_plateau[] = 1389 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 }; 1390 1391 static __inline__ unsigned short guess_mtu(unsigned short old_mtu) 1392 { 1393 int i; 1394 1395 for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++) 1396 if (old_mtu > mtu_plateau[i]) 1397 return mtu_plateau[i]; 1398 return 68; 1399 } 1400 1401 unsigned short ip_rt_frag_needed(struct iphdr *iph, unsigned short new_mtu) 1402 { 1403 int i; 1404 unsigned short old_mtu = ntohs(iph->tot_len); 1405 struct rtable *rth; 1406 __be32 skeys[2] = { iph->saddr, 0, }; 1407 __be32 daddr = iph->daddr; 1408 unsigned short est_mtu = 0; 1409 1410 if (ipv4_config.no_pmtu_disc) 1411 return 0; 1412 1413 for (i = 0; i < 2; i++) { 1414 unsigned hash = rt_hash(daddr, skeys[i], 0); 1415 1416 rcu_read_lock(); 1417 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; 1418 rth = rcu_dereference(rth->u.rt_next)) { 1419 if (rth->fl.fl4_dst == daddr && 1420 rth->fl.fl4_src == skeys[i] && 1421 rth->rt_dst == daddr && 1422 rth->rt_src == iph->saddr && 1423 rth->fl.iif == 0 && 1424 !(dst_metric_locked(&rth->u.dst, RTAX_MTU))) { 1425 unsigned short mtu = new_mtu; 1426 1427 if (new_mtu < 68 || new_mtu >= old_mtu) { 1428 1429 /* BSD 4.2 compatibility hack :-( */ 1430 if (mtu == 0 && 1431 old_mtu >= rth->u.dst.metrics[RTAX_MTU-1] && 1432 old_mtu >= 68 + (iph->ihl << 2)) 1433 old_mtu -= iph->ihl << 2; 1434 1435 mtu = guess_mtu(old_mtu); 1436 } 1437 if (mtu <= rth->u.dst.metrics[RTAX_MTU-1]) { 1438 if (mtu < rth->u.dst.metrics[RTAX_MTU-1]) { 1439 dst_confirm(&rth->u.dst); 1440 if (mtu < ip_rt_min_pmtu) { 1441 mtu = ip_rt_min_pmtu; 1442 rth->u.dst.metrics[RTAX_LOCK-1] |= 1443 (1 << RTAX_MTU); 1444 } 1445 rth->u.dst.metrics[RTAX_MTU-1] = mtu; 1446 dst_set_expires(&rth->u.dst, 1447 ip_rt_mtu_expires); 1448 } 1449 est_mtu = mtu; 1450 } 1451 } 1452 } 1453 rcu_read_unlock(); 1454 } 1455 return est_mtu ? : new_mtu; 1456 } 1457 1458 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu) 1459 { 1460 if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= 68 && 1461 !(dst_metric_locked(dst, RTAX_MTU))) { 1462 if (mtu < ip_rt_min_pmtu) { 1463 mtu = ip_rt_min_pmtu; 1464 dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU); 1465 } 1466 dst->metrics[RTAX_MTU-1] = mtu; 1467 dst_set_expires(dst, ip_rt_mtu_expires); 1468 call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst); 1469 } 1470 } 1471 1472 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1473 { 1474 return NULL; 1475 } 1476 1477 static void ipv4_dst_destroy(struct dst_entry *dst) 1478 { 1479 struct rtable *rt = (struct rtable *) dst; 1480 struct inet_peer *peer = rt->peer; 1481 struct in_device *idev = rt->idev; 1482 1483 if (peer) { 1484 rt->peer = NULL; 1485 inet_putpeer(peer); 1486 } 1487 1488 if (idev) { 1489 rt->idev = NULL; 1490 in_dev_put(idev); 1491 } 1492 } 1493 1494 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 1495 int how) 1496 { 1497 struct rtable *rt = (struct rtable *) dst; 1498 struct in_device *idev = rt->idev; 1499 if (dev != &loopback_dev && idev && idev->dev == dev) { 1500 struct in_device *loopback_idev = in_dev_get(&loopback_dev); 1501 if (loopback_idev) { 1502 rt->idev = loopback_idev; 1503 in_dev_put(idev); 1504 } 1505 } 1506 } 1507 1508 static void ipv4_link_failure(struct sk_buff *skb) 1509 { 1510 struct rtable *rt; 1511 1512 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1513 1514 rt = (struct rtable *) skb->dst; 1515 if (rt) 1516 dst_set_expires(&rt->u.dst, 0); 1517 } 1518 1519 static int ip_rt_bug(struct sk_buff *skb) 1520 { 1521 printk(KERN_DEBUG "ip_rt_bug: %u.%u.%u.%u -> %u.%u.%u.%u, %s\n", 1522 NIPQUAD(skb->nh.iph->saddr), NIPQUAD(skb->nh.iph->daddr), 1523 skb->dev ? skb->dev->name : "?"); 1524 kfree_skb(skb); 1525 return 0; 1526 } 1527 1528 /* 1529 We do not cache source address of outgoing interface, 1530 because it is used only by IP RR, TS and SRR options, 1531 so that it out of fast path. 1532 1533 BTW remember: "addr" is allowed to be not aligned 1534 in IP options! 1535 */ 1536 1537 void ip_rt_get_source(u8 *addr, struct rtable *rt) 1538 { 1539 __be32 src; 1540 struct fib_result res; 1541 1542 if (rt->fl.iif == 0) 1543 src = rt->rt_src; 1544 else if (fib_lookup(&rt->fl, &res) == 0) { 1545 src = FIB_RES_PREFSRC(res); 1546 fib_res_put(&res); 1547 } else 1548 src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway, 1549 RT_SCOPE_UNIVERSE); 1550 memcpy(addr, &src, 4); 1551 } 1552 1553 #ifdef CONFIG_NET_CLS_ROUTE 1554 static void set_class_tag(struct rtable *rt, u32 tag) 1555 { 1556 if (!(rt->u.dst.tclassid & 0xFFFF)) 1557 rt->u.dst.tclassid |= tag & 0xFFFF; 1558 if (!(rt->u.dst.tclassid & 0xFFFF0000)) 1559 rt->u.dst.tclassid |= tag & 0xFFFF0000; 1560 } 1561 #endif 1562 1563 static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag) 1564 { 1565 struct fib_info *fi = res->fi; 1566 1567 if (fi) { 1568 if (FIB_RES_GW(*res) && 1569 FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) 1570 rt->rt_gateway = FIB_RES_GW(*res); 1571 memcpy(rt->u.dst.metrics, fi->fib_metrics, 1572 sizeof(rt->u.dst.metrics)); 1573 if (fi->fib_mtu == 0) { 1574 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu; 1575 if (rt->u.dst.metrics[RTAX_LOCK-1] & (1 << RTAX_MTU) && 1576 rt->rt_gateway != rt->rt_dst && 1577 rt->u.dst.dev->mtu > 576) 1578 rt->u.dst.metrics[RTAX_MTU-1] = 576; 1579 } 1580 #ifdef CONFIG_NET_CLS_ROUTE 1581 rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid; 1582 #endif 1583 } else 1584 rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu; 1585 1586 if (rt->u.dst.metrics[RTAX_HOPLIMIT-1] == 0) 1587 rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl; 1588 if (rt->u.dst.metrics[RTAX_MTU-1] > IP_MAX_MTU) 1589 rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU; 1590 if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0) 1591 rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40, 1592 ip_rt_min_advmss); 1593 if (rt->u.dst.metrics[RTAX_ADVMSS-1] > 65535 - 40) 1594 rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40; 1595 1596 #ifdef CONFIG_NET_CLS_ROUTE 1597 #ifdef CONFIG_IP_MULTIPLE_TABLES 1598 set_class_tag(rt, fib_rules_tclass(res)); 1599 #endif 1600 set_class_tag(rt, itag); 1601 #endif 1602 rt->rt_type = res->type; 1603 } 1604 1605 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1606 u8 tos, struct net_device *dev, int our) 1607 { 1608 unsigned hash; 1609 struct rtable *rth; 1610 __be32 spec_dst; 1611 struct in_device *in_dev = in_dev_get(dev); 1612 u32 itag = 0; 1613 1614 /* Primary sanity checks. */ 1615 1616 if (in_dev == NULL) 1617 return -EINVAL; 1618 1619 if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr) || 1620 skb->protocol != htons(ETH_P_IP)) 1621 goto e_inval; 1622 1623 if (ZERONET(saddr)) { 1624 if (!LOCAL_MCAST(daddr)) 1625 goto e_inval; 1626 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); 1627 } else if (fib_validate_source(saddr, 0, tos, 0, 1628 dev, &spec_dst, &itag) < 0) 1629 goto e_inval; 1630 1631 rth = dst_alloc(&ipv4_dst_ops); 1632 if (!rth) 1633 goto e_nobufs; 1634 1635 rth->u.dst.output= ip_rt_bug; 1636 1637 atomic_set(&rth->u.dst.__refcnt, 1); 1638 rth->u.dst.flags= DST_HOST; 1639 if (in_dev->cnf.no_policy) 1640 rth->u.dst.flags |= DST_NOPOLICY; 1641 rth->fl.fl4_dst = daddr; 1642 rth->rt_dst = daddr; 1643 rth->fl.fl4_tos = tos; 1644 rth->fl.mark = skb->mark; 1645 rth->fl.fl4_src = saddr; 1646 rth->rt_src = saddr; 1647 #ifdef CONFIG_NET_CLS_ROUTE 1648 rth->u.dst.tclassid = itag; 1649 #endif 1650 rth->rt_iif = 1651 rth->fl.iif = dev->ifindex; 1652 rth->u.dst.dev = &loopback_dev; 1653 dev_hold(rth->u.dst.dev); 1654 rth->idev = in_dev_get(rth->u.dst.dev); 1655 rth->fl.oif = 0; 1656 rth->rt_gateway = daddr; 1657 rth->rt_spec_dst= spec_dst; 1658 rth->rt_type = RTN_MULTICAST; 1659 rth->rt_flags = RTCF_MULTICAST; 1660 if (our) { 1661 rth->u.dst.input= ip_local_deliver; 1662 rth->rt_flags |= RTCF_LOCAL; 1663 } 1664 1665 #ifdef CONFIG_IP_MROUTE 1666 if (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev)) 1667 rth->u.dst.input = ip_mr_input; 1668 #endif 1669 RT_CACHE_STAT_INC(in_slow_mc); 1670 1671 in_dev_put(in_dev); 1672 hash = rt_hash(daddr, saddr, dev->ifindex); 1673 return rt_intern_hash(hash, rth, (struct rtable**) &skb->dst); 1674 1675 e_nobufs: 1676 in_dev_put(in_dev); 1677 return -ENOBUFS; 1678 1679 e_inval: 1680 in_dev_put(in_dev); 1681 return -EINVAL; 1682 } 1683 1684 1685 static void ip_handle_martian_source(struct net_device *dev, 1686 struct in_device *in_dev, 1687 struct sk_buff *skb, 1688 __be32 daddr, 1689 __be32 saddr) 1690 { 1691 RT_CACHE_STAT_INC(in_martian_src); 1692 #ifdef CONFIG_IP_ROUTE_VERBOSE 1693 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1694 /* 1695 * RFC1812 recommendation, if source is martian, 1696 * the only hint is MAC header. 1697 */ 1698 printk(KERN_WARNING "martian source %u.%u.%u.%u from " 1699 "%u.%u.%u.%u, on dev %s\n", 1700 NIPQUAD(daddr), NIPQUAD(saddr), dev->name); 1701 if (dev->hard_header_len && skb->mac.raw) { 1702 int i; 1703 unsigned char *p = skb->mac.raw; 1704 printk(KERN_WARNING "ll header: "); 1705 for (i = 0; i < dev->hard_header_len; i++, p++) { 1706 printk("%02x", *p); 1707 if (i < (dev->hard_header_len - 1)) 1708 printk(":"); 1709 } 1710 printk("\n"); 1711 } 1712 } 1713 #endif 1714 } 1715 1716 static inline int __mkroute_input(struct sk_buff *skb, 1717 struct fib_result* res, 1718 struct in_device *in_dev, 1719 __be32 daddr, __be32 saddr, u32 tos, 1720 struct rtable **result) 1721 { 1722 1723 struct rtable *rth; 1724 int err; 1725 struct in_device *out_dev; 1726 unsigned flags = 0; 1727 __be32 spec_dst; 1728 u32 itag; 1729 1730 /* get a working reference to the output device */ 1731 out_dev = in_dev_get(FIB_RES_DEV(*res)); 1732 if (out_dev == NULL) { 1733 if (net_ratelimit()) 1734 printk(KERN_CRIT "Bug in ip_route_input" \ 1735 "_slow(). Please, report\n"); 1736 return -EINVAL; 1737 } 1738 1739 1740 err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res), 1741 in_dev->dev, &spec_dst, &itag); 1742 if (err < 0) { 1743 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1744 saddr); 1745 1746 err = -EINVAL; 1747 goto cleanup; 1748 } 1749 1750 if (err) 1751 flags |= RTCF_DIRECTSRC; 1752 1753 if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) && 1754 (IN_DEV_SHARED_MEDIA(out_dev) || 1755 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1756 flags |= RTCF_DOREDIRECT; 1757 1758 if (skb->protocol != htons(ETH_P_IP)) { 1759 /* Not IP (i.e. ARP). Do not create route, if it is 1760 * invalid for proxy arp. DNAT routes are always valid. 1761 */ 1762 if (out_dev == in_dev && !(flags & RTCF_DNAT)) { 1763 err = -EINVAL; 1764 goto cleanup; 1765 } 1766 } 1767 1768 1769 rth = dst_alloc(&ipv4_dst_ops); 1770 if (!rth) { 1771 err = -ENOBUFS; 1772 goto cleanup; 1773 } 1774 1775 atomic_set(&rth->u.dst.__refcnt, 1); 1776 rth->u.dst.flags= DST_HOST; 1777 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 1778 if (res->fi->fib_nhs > 1) 1779 rth->u.dst.flags |= DST_BALANCED; 1780 #endif 1781 if (in_dev->cnf.no_policy) 1782 rth->u.dst.flags |= DST_NOPOLICY; 1783 if (out_dev->cnf.no_xfrm) 1784 rth->u.dst.flags |= DST_NOXFRM; 1785 rth->fl.fl4_dst = daddr; 1786 rth->rt_dst = daddr; 1787 rth->fl.fl4_tos = tos; 1788 rth->fl.mark = skb->mark; 1789 rth->fl.fl4_src = saddr; 1790 rth->rt_src = saddr; 1791 rth->rt_gateway = daddr; 1792 rth->rt_iif = 1793 rth->fl.iif = in_dev->dev->ifindex; 1794 rth->u.dst.dev = (out_dev)->dev; 1795 dev_hold(rth->u.dst.dev); 1796 rth->idev = in_dev_get(rth->u.dst.dev); 1797 rth->fl.oif = 0; 1798 rth->rt_spec_dst= spec_dst; 1799 1800 rth->u.dst.input = ip_forward; 1801 rth->u.dst.output = ip_output; 1802 1803 rt_set_nexthop(rth, res, itag); 1804 1805 rth->rt_flags = flags; 1806 1807 *result = rth; 1808 err = 0; 1809 cleanup: 1810 /* release the working reference to the output device */ 1811 in_dev_put(out_dev); 1812 return err; 1813 } 1814 1815 static inline int ip_mkroute_input_def(struct sk_buff *skb, 1816 struct fib_result* res, 1817 const struct flowi *fl, 1818 struct in_device *in_dev, 1819 __be32 daddr, __be32 saddr, u32 tos) 1820 { 1821 struct rtable* rth = NULL; 1822 int err; 1823 unsigned hash; 1824 1825 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1826 if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0) 1827 fib_select_multipath(fl, res); 1828 #endif 1829 1830 /* create a routing cache entry */ 1831 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth); 1832 if (err) 1833 return err; 1834 1835 /* put it into the cache */ 1836 hash = rt_hash(daddr, saddr, fl->iif); 1837 return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst); 1838 } 1839 1840 static inline int ip_mkroute_input(struct sk_buff *skb, 1841 struct fib_result* res, 1842 const struct flowi *fl, 1843 struct in_device *in_dev, 1844 __be32 daddr, __be32 saddr, u32 tos) 1845 { 1846 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 1847 struct rtable* rth = NULL, *rtres; 1848 unsigned char hop, hopcount; 1849 int err = -EINVAL; 1850 unsigned int hash; 1851 1852 if (res->fi) 1853 hopcount = res->fi->fib_nhs; 1854 else 1855 hopcount = 1; 1856 1857 /* distinguish between multipath and singlepath */ 1858 if (hopcount < 2) 1859 return ip_mkroute_input_def(skb, res, fl, in_dev, daddr, 1860 saddr, tos); 1861 1862 /* add all alternatives to the routing cache */ 1863 for (hop = 0; hop < hopcount; hop++) { 1864 res->nh_sel = hop; 1865 1866 /* put reference to previous result */ 1867 if (hop) 1868 ip_rt_put(rtres); 1869 1870 /* create a routing cache entry */ 1871 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, 1872 &rth); 1873 if (err) 1874 return err; 1875 1876 /* put it into the cache */ 1877 hash = rt_hash(daddr, saddr, fl->iif); 1878 err = rt_intern_hash(hash, rth, &rtres); 1879 if (err) 1880 return err; 1881 1882 /* forward hop information to multipath impl. */ 1883 multipath_set_nhinfo(rth, 1884 FIB_RES_NETWORK(*res), 1885 FIB_RES_NETMASK(*res), 1886 res->prefixlen, 1887 &FIB_RES_NH(*res)); 1888 } 1889 skb->dst = &rtres->u.dst; 1890 return err; 1891 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 1892 return ip_mkroute_input_def(skb, res, fl, in_dev, daddr, saddr, tos); 1893 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 1894 } 1895 1896 1897 /* 1898 * NOTE. We drop all the packets that has local source 1899 * addresses, because every properly looped back packet 1900 * must have correct destination already attached by output routine. 1901 * 1902 * Such approach solves two big problems: 1903 * 1. Not simplex devices are handled properly. 1904 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1905 */ 1906 1907 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1908 u8 tos, struct net_device *dev) 1909 { 1910 struct fib_result res; 1911 struct in_device *in_dev = in_dev_get(dev); 1912 struct flowi fl = { .nl_u = { .ip4_u = 1913 { .daddr = daddr, 1914 .saddr = saddr, 1915 .tos = tos, 1916 .scope = RT_SCOPE_UNIVERSE, 1917 } }, 1918 .mark = skb->mark, 1919 .iif = dev->ifindex }; 1920 unsigned flags = 0; 1921 u32 itag = 0; 1922 struct rtable * rth; 1923 unsigned hash; 1924 __be32 spec_dst; 1925 int err = -EINVAL; 1926 int free_res = 0; 1927 1928 /* IP on this device is disabled. */ 1929 1930 if (!in_dev) 1931 goto out; 1932 1933 /* Check for the most weird martians, which can be not detected 1934 by fib_lookup. 1935 */ 1936 1937 if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr)) 1938 goto martian_source; 1939 1940 if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0)) 1941 goto brd_input; 1942 1943 /* Accept zero addresses only to limited broadcast; 1944 * I even do not know to fix it or not. Waiting for complains :-) 1945 */ 1946 if (ZERONET(saddr)) 1947 goto martian_source; 1948 1949 if (BADCLASS(daddr) || ZERONET(daddr) || LOOPBACK(daddr)) 1950 goto martian_destination; 1951 1952 /* 1953 * Now we are ready to route packet. 1954 */ 1955 if ((err = fib_lookup(&fl, &res)) != 0) { 1956 if (!IN_DEV_FORWARD(in_dev)) 1957 goto e_hostunreach; 1958 goto no_route; 1959 } 1960 free_res = 1; 1961 1962 RT_CACHE_STAT_INC(in_slow_tot); 1963 1964 if (res.type == RTN_BROADCAST) 1965 goto brd_input; 1966 1967 if (res.type == RTN_LOCAL) { 1968 int result; 1969 result = fib_validate_source(saddr, daddr, tos, 1970 loopback_dev.ifindex, 1971 dev, &spec_dst, &itag); 1972 if (result < 0) 1973 goto martian_source; 1974 if (result) 1975 flags |= RTCF_DIRECTSRC; 1976 spec_dst = daddr; 1977 goto local_input; 1978 } 1979 1980 if (!IN_DEV_FORWARD(in_dev)) 1981 goto e_hostunreach; 1982 if (res.type != RTN_UNICAST) 1983 goto martian_destination; 1984 1985 err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos); 1986 if (err == -ENOBUFS) 1987 goto e_nobufs; 1988 if (err == -EINVAL) 1989 goto e_inval; 1990 1991 done: 1992 in_dev_put(in_dev); 1993 if (free_res) 1994 fib_res_put(&res); 1995 out: return err; 1996 1997 brd_input: 1998 if (skb->protocol != htons(ETH_P_IP)) 1999 goto e_inval; 2000 2001 if (ZERONET(saddr)) 2002 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK); 2003 else { 2004 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst, 2005 &itag); 2006 if (err < 0) 2007 goto martian_source; 2008 if (err) 2009 flags |= RTCF_DIRECTSRC; 2010 } 2011 flags |= RTCF_BROADCAST; 2012 res.type = RTN_BROADCAST; 2013 RT_CACHE_STAT_INC(in_brd); 2014 2015 local_input: 2016 rth = dst_alloc(&ipv4_dst_ops); 2017 if (!rth) 2018 goto e_nobufs; 2019 2020 rth->u.dst.output= ip_rt_bug; 2021 2022 atomic_set(&rth->u.dst.__refcnt, 1); 2023 rth->u.dst.flags= DST_HOST; 2024 if (in_dev->cnf.no_policy) 2025 rth->u.dst.flags |= DST_NOPOLICY; 2026 rth->fl.fl4_dst = daddr; 2027 rth->rt_dst = daddr; 2028 rth->fl.fl4_tos = tos; 2029 rth->fl.mark = skb->mark; 2030 rth->fl.fl4_src = saddr; 2031 rth->rt_src = saddr; 2032 #ifdef CONFIG_NET_CLS_ROUTE 2033 rth->u.dst.tclassid = itag; 2034 #endif 2035 rth->rt_iif = 2036 rth->fl.iif = dev->ifindex; 2037 rth->u.dst.dev = &loopback_dev; 2038 dev_hold(rth->u.dst.dev); 2039 rth->idev = in_dev_get(rth->u.dst.dev); 2040 rth->rt_gateway = daddr; 2041 rth->rt_spec_dst= spec_dst; 2042 rth->u.dst.input= ip_local_deliver; 2043 rth->rt_flags = flags|RTCF_LOCAL; 2044 if (res.type == RTN_UNREACHABLE) { 2045 rth->u.dst.input= ip_error; 2046 rth->u.dst.error= -err; 2047 rth->rt_flags &= ~RTCF_LOCAL; 2048 } 2049 rth->rt_type = res.type; 2050 hash = rt_hash(daddr, saddr, fl.iif); 2051 err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst); 2052 goto done; 2053 2054 no_route: 2055 RT_CACHE_STAT_INC(in_no_route); 2056 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE); 2057 res.type = RTN_UNREACHABLE; 2058 goto local_input; 2059 2060 /* 2061 * Do not cache martian addresses: they should be logged (RFC1812) 2062 */ 2063 martian_destination: 2064 RT_CACHE_STAT_INC(in_martian_dst); 2065 #ifdef CONFIG_IP_ROUTE_VERBOSE 2066 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) 2067 printk(KERN_WARNING "martian destination %u.%u.%u.%u from " 2068 "%u.%u.%u.%u, dev %s\n", 2069 NIPQUAD(daddr), NIPQUAD(saddr), dev->name); 2070 #endif 2071 2072 e_hostunreach: 2073 err = -EHOSTUNREACH; 2074 goto done; 2075 2076 e_inval: 2077 err = -EINVAL; 2078 goto done; 2079 2080 e_nobufs: 2081 err = -ENOBUFS; 2082 goto done; 2083 2084 martian_source: 2085 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 2086 goto e_inval; 2087 } 2088 2089 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr, 2090 u8 tos, struct net_device *dev) 2091 { 2092 struct rtable * rth; 2093 unsigned hash; 2094 int iif = dev->ifindex; 2095 2096 tos &= IPTOS_RT_MASK; 2097 hash = rt_hash(daddr, saddr, iif); 2098 2099 rcu_read_lock(); 2100 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; 2101 rth = rcu_dereference(rth->u.rt_next)) { 2102 if (rth->fl.fl4_dst == daddr && 2103 rth->fl.fl4_src == saddr && 2104 rth->fl.iif == iif && 2105 rth->fl.oif == 0 && 2106 rth->fl.mark == skb->mark && 2107 rth->fl.fl4_tos == tos) { 2108 rth->u.dst.lastuse = jiffies; 2109 dst_hold(&rth->u.dst); 2110 rth->u.dst.__use++; 2111 RT_CACHE_STAT_INC(in_hit); 2112 rcu_read_unlock(); 2113 skb->dst = (struct dst_entry*)rth; 2114 return 0; 2115 } 2116 RT_CACHE_STAT_INC(in_hlist_search); 2117 } 2118 rcu_read_unlock(); 2119 2120 /* Multicast recognition logic is moved from route cache to here. 2121 The problem was that too many Ethernet cards have broken/missing 2122 hardware multicast filters :-( As result the host on multicasting 2123 network acquires a lot of useless route cache entries, sort of 2124 SDR messages from all the world. Now we try to get rid of them. 2125 Really, provided software IP multicast filter is organized 2126 reasonably (at least, hashed), it does not result in a slowdown 2127 comparing with route cache reject entries. 2128 Note, that multicast routers are not affected, because 2129 route cache entry is created eventually. 2130 */ 2131 if (MULTICAST(daddr)) { 2132 struct in_device *in_dev; 2133 2134 rcu_read_lock(); 2135 if ((in_dev = __in_dev_get_rcu(dev)) != NULL) { 2136 int our = ip_check_mc(in_dev, daddr, saddr, 2137 skb->nh.iph->protocol); 2138 if (our 2139 #ifdef CONFIG_IP_MROUTE 2140 || (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev)) 2141 #endif 2142 ) { 2143 rcu_read_unlock(); 2144 return ip_route_input_mc(skb, daddr, saddr, 2145 tos, dev, our); 2146 } 2147 } 2148 rcu_read_unlock(); 2149 return -EINVAL; 2150 } 2151 return ip_route_input_slow(skb, daddr, saddr, tos, dev); 2152 } 2153 2154 static inline int __mkroute_output(struct rtable **result, 2155 struct fib_result* res, 2156 const struct flowi *fl, 2157 const struct flowi *oldflp, 2158 struct net_device *dev_out, 2159 unsigned flags) 2160 { 2161 struct rtable *rth; 2162 struct in_device *in_dev; 2163 u32 tos = RT_FL_TOS(oldflp); 2164 int err = 0; 2165 2166 if (LOOPBACK(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK)) 2167 return -EINVAL; 2168 2169 if (fl->fl4_dst == htonl(0xFFFFFFFF)) 2170 res->type = RTN_BROADCAST; 2171 else if (MULTICAST(fl->fl4_dst)) 2172 res->type = RTN_MULTICAST; 2173 else if (BADCLASS(fl->fl4_dst) || ZERONET(fl->fl4_dst)) 2174 return -EINVAL; 2175 2176 if (dev_out->flags & IFF_LOOPBACK) 2177 flags |= RTCF_LOCAL; 2178 2179 /* get work reference to inet device */ 2180 in_dev = in_dev_get(dev_out); 2181 if (!in_dev) 2182 return -EINVAL; 2183 2184 if (res->type == RTN_BROADCAST) { 2185 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2186 if (res->fi) { 2187 fib_info_put(res->fi); 2188 res->fi = NULL; 2189 } 2190 } else if (res->type == RTN_MULTICAST) { 2191 flags |= RTCF_MULTICAST|RTCF_LOCAL; 2192 if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src, 2193 oldflp->proto)) 2194 flags &= ~RTCF_LOCAL; 2195 /* If multicast route do not exist use 2196 default one, but do not gateway in this case. 2197 Yes, it is hack. 2198 */ 2199 if (res->fi && res->prefixlen < 4) { 2200 fib_info_put(res->fi); 2201 res->fi = NULL; 2202 } 2203 } 2204 2205 2206 rth = dst_alloc(&ipv4_dst_ops); 2207 if (!rth) { 2208 err = -ENOBUFS; 2209 goto cleanup; 2210 } 2211 2212 atomic_set(&rth->u.dst.__refcnt, 1); 2213 rth->u.dst.flags= DST_HOST; 2214 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 2215 if (res->fi) { 2216 rth->rt_multipath_alg = res->fi->fib_mp_alg; 2217 if (res->fi->fib_nhs > 1) 2218 rth->u.dst.flags |= DST_BALANCED; 2219 } 2220 #endif 2221 if (in_dev->cnf.no_xfrm) 2222 rth->u.dst.flags |= DST_NOXFRM; 2223 if (in_dev->cnf.no_policy) 2224 rth->u.dst.flags |= DST_NOPOLICY; 2225 2226 rth->fl.fl4_dst = oldflp->fl4_dst; 2227 rth->fl.fl4_tos = tos; 2228 rth->fl.fl4_src = oldflp->fl4_src; 2229 rth->fl.oif = oldflp->oif; 2230 rth->fl.mark = oldflp->mark; 2231 rth->rt_dst = fl->fl4_dst; 2232 rth->rt_src = fl->fl4_src; 2233 rth->rt_iif = oldflp->oif ? : dev_out->ifindex; 2234 /* get references to the devices that are to be hold by the routing 2235 cache entry */ 2236 rth->u.dst.dev = dev_out; 2237 dev_hold(dev_out); 2238 rth->idev = in_dev_get(dev_out); 2239 rth->rt_gateway = fl->fl4_dst; 2240 rth->rt_spec_dst= fl->fl4_src; 2241 2242 rth->u.dst.output=ip_output; 2243 2244 RT_CACHE_STAT_INC(out_slow_tot); 2245 2246 if (flags & RTCF_LOCAL) { 2247 rth->u.dst.input = ip_local_deliver; 2248 rth->rt_spec_dst = fl->fl4_dst; 2249 } 2250 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2251 rth->rt_spec_dst = fl->fl4_src; 2252 if (flags & RTCF_LOCAL && 2253 !(dev_out->flags & IFF_LOOPBACK)) { 2254 rth->u.dst.output = ip_mc_output; 2255 RT_CACHE_STAT_INC(out_slow_mc); 2256 } 2257 #ifdef CONFIG_IP_MROUTE 2258 if (res->type == RTN_MULTICAST) { 2259 if (IN_DEV_MFORWARD(in_dev) && 2260 !LOCAL_MCAST(oldflp->fl4_dst)) { 2261 rth->u.dst.input = ip_mr_input; 2262 rth->u.dst.output = ip_mc_output; 2263 } 2264 } 2265 #endif 2266 } 2267 2268 rt_set_nexthop(rth, res, 0); 2269 2270 rth->rt_flags = flags; 2271 2272 *result = rth; 2273 cleanup: 2274 /* release work reference to inet device */ 2275 in_dev_put(in_dev); 2276 2277 return err; 2278 } 2279 2280 static inline int ip_mkroute_output_def(struct rtable **rp, 2281 struct fib_result* res, 2282 const struct flowi *fl, 2283 const struct flowi *oldflp, 2284 struct net_device *dev_out, 2285 unsigned flags) 2286 { 2287 struct rtable *rth = NULL; 2288 int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags); 2289 unsigned hash; 2290 if (err == 0) { 2291 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif); 2292 err = rt_intern_hash(hash, rth, rp); 2293 } 2294 2295 return err; 2296 } 2297 2298 static inline int ip_mkroute_output(struct rtable** rp, 2299 struct fib_result* res, 2300 const struct flowi *fl, 2301 const struct flowi *oldflp, 2302 struct net_device *dev_out, 2303 unsigned flags) 2304 { 2305 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 2306 unsigned char hop; 2307 unsigned hash; 2308 int err = -EINVAL; 2309 struct rtable *rth = NULL; 2310 2311 if (res->fi && res->fi->fib_nhs > 1) { 2312 unsigned char hopcount = res->fi->fib_nhs; 2313 2314 for (hop = 0; hop < hopcount; hop++) { 2315 struct net_device *dev2nexthop; 2316 2317 res->nh_sel = hop; 2318 2319 /* hold a work reference to the output device */ 2320 dev2nexthop = FIB_RES_DEV(*res); 2321 dev_hold(dev2nexthop); 2322 2323 /* put reference to previous result */ 2324 if (hop) 2325 ip_rt_put(*rp); 2326 2327 err = __mkroute_output(&rth, res, fl, oldflp, 2328 dev2nexthop, flags); 2329 2330 if (err != 0) 2331 goto cleanup; 2332 2333 hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, 2334 oldflp->oif); 2335 err = rt_intern_hash(hash, rth, rp); 2336 2337 /* forward hop information to multipath impl. */ 2338 multipath_set_nhinfo(rth, 2339 FIB_RES_NETWORK(*res), 2340 FIB_RES_NETMASK(*res), 2341 res->prefixlen, 2342 &FIB_RES_NH(*res)); 2343 cleanup: 2344 /* release work reference to output device */ 2345 dev_put(dev2nexthop); 2346 2347 if (err != 0) 2348 return err; 2349 } 2350 return err; 2351 } else { 2352 return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out, 2353 flags); 2354 } 2355 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */ 2356 return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out, flags); 2357 #endif 2358 } 2359 2360 /* 2361 * Major route resolver routine. 2362 */ 2363 2364 static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp) 2365 { 2366 u32 tos = RT_FL_TOS(oldflp); 2367 struct flowi fl = { .nl_u = { .ip4_u = 2368 { .daddr = oldflp->fl4_dst, 2369 .saddr = oldflp->fl4_src, 2370 .tos = tos & IPTOS_RT_MASK, 2371 .scope = ((tos & RTO_ONLINK) ? 2372 RT_SCOPE_LINK : 2373 RT_SCOPE_UNIVERSE), 2374 } }, 2375 .mark = oldflp->mark, 2376 .iif = loopback_dev.ifindex, 2377 .oif = oldflp->oif }; 2378 struct fib_result res; 2379 unsigned flags = 0; 2380 struct net_device *dev_out = NULL; 2381 int free_res = 0; 2382 int err; 2383 2384 2385 res.fi = NULL; 2386 #ifdef CONFIG_IP_MULTIPLE_TABLES 2387 res.r = NULL; 2388 #endif 2389 2390 if (oldflp->fl4_src) { 2391 err = -EINVAL; 2392 if (MULTICAST(oldflp->fl4_src) || 2393 BADCLASS(oldflp->fl4_src) || 2394 ZERONET(oldflp->fl4_src)) 2395 goto out; 2396 2397 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2398 dev_out = ip_dev_find(oldflp->fl4_src); 2399 if (dev_out == NULL) 2400 goto out; 2401 2402 /* I removed check for oif == dev_out->oif here. 2403 It was wrong for two reasons: 2404 1. ip_dev_find(saddr) can return wrong iface, if saddr is 2405 assigned to multiple interfaces. 2406 2. Moreover, we are allowed to send packets with saddr 2407 of another iface. --ANK 2408 */ 2409 2410 if (oldflp->oif == 0 2411 && (MULTICAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF))) { 2412 /* Special hack: user can direct multicasts 2413 and limited broadcast via necessary interface 2414 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2415 This hack is not just for fun, it allows 2416 vic,vat and friends to work. 2417 They bind socket to loopback, set ttl to zero 2418 and expect that it will work. 2419 From the viewpoint of routing cache they are broken, 2420 because we are not allowed to build multicast path 2421 with loopback source addr (look, routing cache 2422 cannot know, that ttl is zero, so that packet 2423 will not leave this host and route is valid). 2424 Luckily, this hack is good workaround. 2425 */ 2426 2427 fl.oif = dev_out->ifindex; 2428 goto make_route; 2429 } 2430 if (dev_out) 2431 dev_put(dev_out); 2432 dev_out = NULL; 2433 } 2434 2435 2436 if (oldflp->oif) { 2437 dev_out = dev_get_by_index(oldflp->oif); 2438 err = -ENODEV; 2439 if (dev_out == NULL) 2440 goto out; 2441 2442 /* RACE: Check return value of inet_select_addr instead. */ 2443 if (__in_dev_get_rtnl(dev_out) == NULL) { 2444 dev_put(dev_out); 2445 goto out; /* Wrong error code */ 2446 } 2447 2448 if (LOCAL_MCAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF)) { 2449 if (!fl.fl4_src) 2450 fl.fl4_src = inet_select_addr(dev_out, 0, 2451 RT_SCOPE_LINK); 2452 goto make_route; 2453 } 2454 if (!fl.fl4_src) { 2455 if (MULTICAST(oldflp->fl4_dst)) 2456 fl.fl4_src = inet_select_addr(dev_out, 0, 2457 fl.fl4_scope); 2458 else if (!oldflp->fl4_dst) 2459 fl.fl4_src = inet_select_addr(dev_out, 0, 2460 RT_SCOPE_HOST); 2461 } 2462 } 2463 2464 if (!fl.fl4_dst) { 2465 fl.fl4_dst = fl.fl4_src; 2466 if (!fl.fl4_dst) 2467 fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK); 2468 if (dev_out) 2469 dev_put(dev_out); 2470 dev_out = &loopback_dev; 2471 dev_hold(dev_out); 2472 fl.oif = loopback_dev.ifindex; 2473 res.type = RTN_LOCAL; 2474 flags |= RTCF_LOCAL; 2475 goto make_route; 2476 } 2477 2478 if (fib_lookup(&fl, &res)) { 2479 res.fi = NULL; 2480 if (oldflp->oif) { 2481 /* Apparently, routing tables are wrong. Assume, 2482 that the destination is on link. 2483 2484 WHY? DW. 2485 Because we are allowed to send to iface 2486 even if it has NO routes and NO assigned 2487 addresses. When oif is specified, routing 2488 tables are looked up with only one purpose: 2489 to catch if destination is gatewayed, rather than 2490 direct. Moreover, if MSG_DONTROUTE is set, 2491 we send packet, ignoring both routing tables 2492 and ifaddr state. --ANK 2493 2494 2495 We could make it even if oif is unknown, 2496 likely IPv6, but we do not. 2497 */ 2498 2499 if (fl.fl4_src == 0) 2500 fl.fl4_src = inet_select_addr(dev_out, 0, 2501 RT_SCOPE_LINK); 2502 res.type = RTN_UNICAST; 2503 goto make_route; 2504 } 2505 if (dev_out) 2506 dev_put(dev_out); 2507 err = -ENETUNREACH; 2508 goto out; 2509 } 2510 free_res = 1; 2511 2512 if (res.type == RTN_LOCAL) { 2513 if (!fl.fl4_src) 2514 fl.fl4_src = fl.fl4_dst; 2515 if (dev_out) 2516 dev_put(dev_out); 2517 dev_out = &loopback_dev; 2518 dev_hold(dev_out); 2519 fl.oif = dev_out->ifindex; 2520 if (res.fi) 2521 fib_info_put(res.fi); 2522 res.fi = NULL; 2523 flags |= RTCF_LOCAL; 2524 goto make_route; 2525 } 2526 2527 #ifdef CONFIG_IP_ROUTE_MULTIPATH 2528 if (res.fi->fib_nhs > 1 && fl.oif == 0) 2529 fib_select_multipath(&fl, &res); 2530 else 2531 #endif 2532 if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif) 2533 fib_select_default(&fl, &res); 2534 2535 if (!fl.fl4_src) 2536 fl.fl4_src = FIB_RES_PREFSRC(res); 2537 2538 if (dev_out) 2539 dev_put(dev_out); 2540 dev_out = FIB_RES_DEV(res); 2541 dev_hold(dev_out); 2542 fl.oif = dev_out->ifindex; 2543 2544 2545 make_route: 2546 err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags); 2547 2548 2549 if (free_res) 2550 fib_res_put(&res); 2551 if (dev_out) 2552 dev_put(dev_out); 2553 out: return err; 2554 } 2555 2556 int __ip_route_output_key(struct rtable **rp, const struct flowi *flp) 2557 { 2558 unsigned hash; 2559 struct rtable *rth; 2560 2561 hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif); 2562 2563 rcu_read_lock_bh(); 2564 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; 2565 rth = rcu_dereference(rth->u.rt_next)) { 2566 if (rth->fl.fl4_dst == flp->fl4_dst && 2567 rth->fl.fl4_src == flp->fl4_src && 2568 rth->fl.iif == 0 && 2569 rth->fl.oif == flp->oif && 2570 rth->fl.mark == flp->mark && 2571 !((rth->fl.fl4_tos ^ flp->fl4_tos) & 2572 (IPTOS_RT_MASK | RTO_ONLINK))) { 2573 2574 /* check for multipath routes and choose one if 2575 * necessary 2576 */ 2577 if (multipath_select_route(flp, rth, rp)) { 2578 dst_hold(&(*rp)->u.dst); 2579 RT_CACHE_STAT_INC(out_hit); 2580 rcu_read_unlock_bh(); 2581 return 0; 2582 } 2583 2584 rth->u.dst.lastuse = jiffies; 2585 dst_hold(&rth->u.dst); 2586 rth->u.dst.__use++; 2587 RT_CACHE_STAT_INC(out_hit); 2588 rcu_read_unlock_bh(); 2589 *rp = rth; 2590 return 0; 2591 } 2592 RT_CACHE_STAT_INC(out_hlist_search); 2593 } 2594 rcu_read_unlock_bh(); 2595 2596 return ip_route_output_slow(rp, flp); 2597 } 2598 2599 EXPORT_SYMBOL_GPL(__ip_route_output_key); 2600 2601 int ip_route_output_flow(struct rtable **rp, struct flowi *flp, struct sock *sk, int flags) 2602 { 2603 int err; 2604 2605 if ((err = __ip_route_output_key(rp, flp)) != 0) 2606 return err; 2607 2608 if (flp->proto) { 2609 if (!flp->fl4_src) 2610 flp->fl4_src = (*rp)->rt_src; 2611 if (!flp->fl4_dst) 2612 flp->fl4_dst = (*rp)->rt_dst; 2613 return xfrm_lookup((struct dst_entry **)rp, flp, sk, flags); 2614 } 2615 2616 return 0; 2617 } 2618 2619 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2620 2621 int ip_route_output_key(struct rtable **rp, struct flowi *flp) 2622 { 2623 return ip_route_output_flow(rp, flp, NULL, 0); 2624 } 2625 2626 static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event, 2627 int nowait, unsigned int flags) 2628 { 2629 struct rtable *rt = (struct rtable*)skb->dst; 2630 struct rtmsg *r; 2631 struct nlmsghdr *nlh; 2632 long expires; 2633 u32 id = 0, ts = 0, tsage = 0, error; 2634 2635 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags); 2636 if (nlh == NULL) 2637 return -ENOBUFS; 2638 2639 r = nlmsg_data(nlh); 2640 r->rtm_family = AF_INET; 2641 r->rtm_dst_len = 32; 2642 r->rtm_src_len = 0; 2643 r->rtm_tos = rt->fl.fl4_tos; 2644 r->rtm_table = RT_TABLE_MAIN; 2645 NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN); 2646 r->rtm_type = rt->rt_type; 2647 r->rtm_scope = RT_SCOPE_UNIVERSE; 2648 r->rtm_protocol = RTPROT_UNSPEC; 2649 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2650 if (rt->rt_flags & RTCF_NOTIFY) 2651 r->rtm_flags |= RTM_F_NOTIFY; 2652 2653 NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst); 2654 2655 if (rt->fl.fl4_src) { 2656 r->rtm_src_len = 32; 2657 NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src); 2658 } 2659 if (rt->u.dst.dev) 2660 NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex); 2661 #ifdef CONFIG_NET_CLS_ROUTE 2662 if (rt->u.dst.tclassid) 2663 NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid); 2664 #endif 2665 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED 2666 if (rt->rt_multipath_alg != IP_MP_ALG_NONE) 2667 NLA_PUT_U32(skb, RTA_MP_ALGO, rt->rt_multipath_alg); 2668 #endif 2669 if (rt->fl.iif) 2670 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst); 2671 else if (rt->rt_src != rt->fl.fl4_src) 2672 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src); 2673 2674 if (rt->rt_dst != rt->rt_gateway) 2675 NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway); 2676 2677 if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0) 2678 goto nla_put_failure; 2679 2680 error = rt->u.dst.error; 2681 expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0; 2682 if (rt->peer) { 2683 id = rt->peer->ip_id_count; 2684 if (rt->peer->tcp_ts_stamp) { 2685 ts = rt->peer->tcp_ts; 2686 tsage = xtime.tv_sec - rt->peer->tcp_ts_stamp; 2687 } 2688 } 2689 2690 if (rt->fl.iif) { 2691 #ifdef CONFIG_IP_MROUTE 2692 __be32 dst = rt->rt_dst; 2693 2694 if (MULTICAST(dst) && !LOCAL_MCAST(dst) && 2695 ipv4_devconf.mc_forwarding) { 2696 int err = ipmr_get_route(skb, r, nowait); 2697 if (err <= 0) { 2698 if (!nowait) { 2699 if (err == 0) 2700 return 0; 2701 goto nla_put_failure; 2702 } else { 2703 if (err == -EMSGSIZE) 2704 goto nla_put_failure; 2705 error = err; 2706 } 2707 } 2708 } else 2709 #endif 2710 NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif); 2711 } 2712 2713 if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage, 2714 expires, error) < 0) 2715 goto nla_put_failure; 2716 2717 return nlmsg_end(skb, nlh); 2718 2719 nla_put_failure: 2720 return nlmsg_cancel(skb, nlh); 2721 } 2722 2723 int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg) 2724 { 2725 struct rtmsg *rtm; 2726 struct nlattr *tb[RTA_MAX+1]; 2727 struct rtable *rt = NULL; 2728 __be32 dst = 0; 2729 __be32 src = 0; 2730 u32 iif; 2731 int err; 2732 struct sk_buff *skb; 2733 2734 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 2735 if (err < 0) 2736 goto errout; 2737 2738 rtm = nlmsg_data(nlh); 2739 2740 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2741 if (skb == NULL) { 2742 err = -ENOBUFS; 2743 goto errout; 2744 } 2745 2746 /* Reserve room for dummy headers, this skb can pass 2747 through good chunk of routing engine. 2748 */ 2749 skb->mac.raw = skb->nh.raw = skb->data; 2750 2751 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 2752 skb->nh.iph->protocol = IPPROTO_ICMP; 2753 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2754 2755 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0; 2756 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0; 2757 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2758 2759 if (iif) { 2760 struct net_device *dev; 2761 2762 dev = __dev_get_by_index(iif); 2763 if (dev == NULL) { 2764 err = -ENODEV; 2765 goto errout_free; 2766 } 2767 2768 skb->protocol = htons(ETH_P_IP); 2769 skb->dev = dev; 2770 local_bh_disable(); 2771 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 2772 local_bh_enable(); 2773 2774 rt = (struct rtable*) skb->dst; 2775 if (err == 0 && rt->u.dst.error) 2776 err = -rt->u.dst.error; 2777 } else { 2778 struct flowi fl = { 2779 .nl_u = { 2780 .ip4_u = { 2781 .daddr = dst, 2782 .saddr = src, 2783 .tos = rtm->rtm_tos, 2784 }, 2785 }, 2786 .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0, 2787 }; 2788 err = ip_route_output_key(&rt, &fl); 2789 } 2790 2791 if (err) 2792 goto errout_free; 2793 2794 skb->dst = &rt->u.dst; 2795 if (rtm->rtm_flags & RTM_F_NOTIFY) 2796 rt->rt_flags |= RTCF_NOTIFY; 2797 2798 err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 2799 RTM_NEWROUTE, 0, 0); 2800 if (err <= 0) 2801 goto errout_free; 2802 2803 err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid); 2804 errout: 2805 return err; 2806 2807 errout_free: 2808 kfree_skb(skb); 2809 goto errout; 2810 } 2811 2812 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) 2813 { 2814 struct rtable *rt; 2815 int h, s_h; 2816 int idx, s_idx; 2817 2818 s_h = cb->args[0]; 2819 s_idx = idx = cb->args[1]; 2820 for (h = 0; h <= rt_hash_mask; h++) { 2821 if (h < s_h) continue; 2822 if (h > s_h) 2823 s_idx = 0; 2824 rcu_read_lock_bh(); 2825 for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt; 2826 rt = rcu_dereference(rt->u.rt_next), idx++) { 2827 if (idx < s_idx) 2828 continue; 2829 skb->dst = dst_clone(&rt->u.dst); 2830 if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid, 2831 cb->nlh->nlmsg_seq, RTM_NEWROUTE, 2832 1, NLM_F_MULTI) <= 0) { 2833 dst_release(xchg(&skb->dst, NULL)); 2834 rcu_read_unlock_bh(); 2835 goto done; 2836 } 2837 dst_release(xchg(&skb->dst, NULL)); 2838 } 2839 rcu_read_unlock_bh(); 2840 } 2841 2842 done: 2843 cb->args[0] = h; 2844 cb->args[1] = idx; 2845 return skb->len; 2846 } 2847 2848 void ip_rt_multicast_event(struct in_device *in_dev) 2849 { 2850 rt_cache_flush(0); 2851 } 2852 2853 #ifdef CONFIG_SYSCTL 2854 static int flush_delay; 2855 2856 static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write, 2857 struct file *filp, void __user *buffer, 2858 size_t *lenp, loff_t *ppos) 2859 { 2860 if (write) { 2861 proc_dointvec(ctl, write, filp, buffer, lenp, ppos); 2862 rt_cache_flush(flush_delay); 2863 return 0; 2864 } 2865 2866 return -EINVAL; 2867 } 2868 2869 static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table, 2870 int __user *name, 2871 int nlen, 2872 void __user *oldval, 2873 size_t __user *oldlenp, 2874 void __user *newval, 2875 size_t newlen, 2876 void **context) 2877 { 2878 int delay; 2879 if (newlen != sizeof(int)) 2880 return -EINVAL; 2881 if (get_user(delay, (int __user *)newval)) 2882 return -EFAULT; 2883 rt_cache_flush(delay); 2884 return 0; 2885 } 2886 2887 ctl_table ipv4_route_table[] = { 2888 { 2889 .ctl_name = NET_IPV4_ROUTE_FLUSH, 2890 .procname = "flush", 2891 .data = &flush_delay, 2892 .maxlen = sizeof(int), 2893 .mode = 0200, 2894 .proc_handler = &ipv4_sysctl_rtcache_flush, 2895 .strategy = &ipv4_sysctl_rtcache_flush_strategy, 2896 }, 2897 { 2898 .ctl_name = NET_IPV4_ROUTE_MIN_DELAY, 2899 .procname = "min_delay", 2900 .data = &ip_rt_min_delay, 2901 .maxlen = sizeof(int), 2902 .mode = 0644, 2903 .proc_handler = &proc_dointvec_jiffies, 2904 .strategy = &sysctl_jiffies, 2905 }, 2906 { 2907 .ctl_name = NET_IPV4_ROUTE_MAX_DELAY, 2908 .procname = "max_delay", 2909 .data = &ip_rt_max_delay, 2910 .maxlen = sizeof(int), 2911 .mode = 0644, 2912 .proc_handler = &proc_dointvec_jiffies, 2913 .strategy = &sysctl_jiffies, 2914 }, 2915 { 2916 .ctl_name = NET_IPV4_ROUTE_GC_THRESH, 2917 .procname = "gc_thresh", 2918 .data = &ipv4_dst_ops.gc_thresh, 2919 .maxlen = sizeof(int), 2920 .mode = 0644, 2921 .proc_handler = &proc_dointvec, 2922 }, 2923 { 2924 .ctl_name = NET_IPV4_ROUTE_MAX_SIZE, 2925 .procname = "max_size", 2926 .data = &ip_rt_max_size, 2927 .maxlen = sizeof(int), 2928 .mode = 0644, 2929 .proc_handler = &proc_dointvec, 2930 }, 2931 { 2932 /* Deprecated. Use gc_min_interval_ms */ 2933 2934 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL, 2935 .procname = "gc_min_interval", 2936 .data = &ip_rt_gc_min_interval, 2937 .maxlen = sizeof(int), 2938 .mode = 0644, 2939 .proc_handler = &proc_dointvec_jiffies, 2940 .strategy = &sysctl_jiffies, 2941 }, 2942 { 2943 .ctl_name = NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS, 2944 .procname = "gc_min_interval_ms", 2945 .data = &ip_rt_gc_min_interval, 2946 .maxlen = sizeof(int), 2947 .mode = 0644, 2948 .proc_handler = &proc_dointvec_ms_jiffies, 2949 .strategy = &sysctl_ms_jiffies, 2950 }, 2951 { 2952 .ctl_name = NET_IPV4_ROUTE_GC_TIMEOUT, 2953 .procname = "gc_timeout", 2954 .data = &ip_rt_gc_timeout, 2955 .maxlen = sizeof(int), 2956 .mode = 0644, 2957 .proc_handler = &proc_dointvec_jiffies, 2958 .strategy = &sysctl_jiffies, 2959 }, 2960 { 2961 .ctl_name = NET_IPV4_ROUTE_GC_INTERVAL, 2962 .procname = "gc_interval", 2963 .data = &ip_rt_gc_interval, 2964 .maxlen = sizeof(int), 2965 .mode = 0644, 2966 .proc_handler = &proc_dointvec_jiffies, 2967 .strategy = &sysctl_jiffies, 2968 }, 2969 { 2970 .ctl_name = NET_IPV4_ROUTE_REDIRECT_LOAD, 2971 .procname = "redirect_load", 2972 .data = &ip_rt_redirect_load, 2973 .maxlen = sizeof(int), 2974 .mode = 0644, 2975 .proc_handler = &proc_dointvec, 2976 }, 2977 { 2978 .ctl_name = NET_IPV4_ROUTE_REDIRECT_NUMBER, 2979 .procname = "redirect_number", 2980 .data = &ip_rt_redirect_number, 2981 .maxlen = sizeof(int), 2982 .mode = 0644, 2983 .proc_handler = &proc_dointvec, 2984 }, 2985 { 2986 .ctl_name = NET_IPV4_ROUTE_REDIRECT_SILENCE, 2987 .procname = "redirect_silence", 2988 .data = &ip_rt_redirect_silence, 2989 .maxlen = sizeof(int), 2990 .mode = 0644, 2991 .proc_handler = &proc_dointvec, 2992 }, 2993 { 2994 .ctl_name = NET_IPV4_ROUTE_ERROR_COST, 2995 .procname = "error_cost", 2996 .data = &ip_rt_error_cost, 2997 .maxlen = sizeof(int), 2998 .mode = 0644, 2999 .proc_handler = &proc_dointvec, 3000 }, 3001 { 3002 .ctl_name = NET_IPV4_ROUTE_ERROR_BURST, 3003 .procname = "error_burst", 3004 .data = &ip_rt_error_burst, 3005 .maxlen = sizeof(int), 3006 .mode = 0644, 3007 .proc_handler = &proc_dointvec, 3008 }, 3009 { 3010 .ctl_name = NET_IPV4_ROUTE_GC_ELASTICITY, 3011 .procname = "gc_elasticity", 3012 .data = &ip_rt_gc_elasticity, 3013 .maxlen = sizeof(int), 3014 .mode = 0644, 3015 .proc_handler = &proc_dointvec, 3016 }, 3017 { 3018 .ctl_name = NET_IPV4_ROUTE_MTU_EXPIRES, 3019 .procname = "mtu_expires", 3020 .data = &ip_rt_mtu_expires, 3021 .maxlen = sizeof(int), 3022 .mode = 0644, 3023 .proc_handler = &proc_dointvec_jiffies, 3024 .strategy = &sysctl_jiffies, 3025 }, 3026 { 3027 .ctl_name = NET_IPV4_ROUTE_MIN_PMTU, 3028 .procname = "min_pmtu", 3029 .data = &ip_rt_min_pmtu, 3030 .maxlen = sizeof(int), 3031 .mode = 0644, 3032 .proc_handler = &proc_dointvec, 3033 }, 3034 { 3035 .ctl_name = NET_IPV4_ROUTE_MIN_ADVMSS, 3036 .procname = "min_adv_mss", 3037 .data = &ip_rt_min_advmss, 3038 .maxlen = sizeof(int), 3039 .mode = 0644, 3040 .proc_handler = &proc_dointvec, 3041 }, 3042 { 3043 .ctl_name = NET_IPV4_ROUTE_SECRET_INTERVAL, 3044 .procname = "secret_interval", 3045 .data = &ip_rt_secret_interval, 3046 .maxlen = sizeof(int), 3047 .mode = 0644, 3048 .proc_handler = &proc_dointvec_jiffies, 3049 .strategy = &sysctl_jiffies, 3050 }, 3051 { .ctl_name = 0 } 3052 }; 3053 #endif 3054 3055 #ifdef CONFIG_NET_CLS_ROUTE 3056 struct ip_rt_acct *ip_rt_acct; 3057 3058 /* This code sucks. But you should have seen it before! --RR */ 3059 3060 /* IP route accounting ptr for this logical cpu number. */ 3061 #define IP_RT_ACCT_CPU(i) (ip_rt_acct + i * 256) 3062 3063 #ifdef CONFIG_PROC_FS 3064 static int ip_rt_acct_read(char *buffer, char **start, off_t offset, 3065 int length, int *eof, void *data) 3066 { 3067 unsigned int i; 3068 3069 if ((offset & 3) || (length & 3)) 3070 return -EIO; 3071 3072 if (offset >= sizeof(struct ip_rt_acct) * 256) { 3073 *eof = 1; 3074 return 0; 3075 } 3076 3077 if (offset + length >= sizeof(struct ip_rt_acct) * 256) { 3078 length = sizeof(struct ip_rt_acct) * 256 - offset; 3079 *eof = 1; 3080 } 3081 3082 offset /= sizeof(u32); 3083 3084 if (length > 0) { 3085 u32 *src = ((u32 *) IP_RT_ACCT_CPU(0)) + offset; 3086 u32 *dst = (u32 *) buffer; 3087 3088 /* Copy first cpu. */ 3089 *start = buffer; 3090 memcpy(dst, src, length); 3091 3092 /* Add the other cpus in, one int at a time */ 3093 for_each_possible_cpu(i) { 3094 unsigned int j; 3095 3096 src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset; 3097 3098 for (j = 0; j < length/4; j++) 3099 dst[j] += src[j]; 3100 } 3101 } 3102 return length; 3103 } 3104 #endif /* CONFIG_PROC_FS */ 3105 #endif /* CONFIG_NET_CLS_ROUTE */ 3106 3107 static __initdata unsigned long rhash_entries; 3108 static int __init set_rhash_entries(char *str) 3109 { 3110 if (!str) 3111 return 0; 3112 rhash_entries = simple_strtoul(str, &str, 0); 3113 return 1; 3114 } 3115 __setup("rhash_entries=", set_rhash_entries); 3116 3117 int __init ip_rt_init(void) 3118 { 3119 int rc = 0; 3120 3121 rt_hash_rnd = (int) ((num_physpages ^ (num_physpages>>8)) ^ 3122 (jiffies ^ (jiffies >> 7))); 3123 3124 #ifdef CONFIG_NET_CLS_ROUTE 3125 { 3126 int order; 3127 for (order = 0; 3128 (PAGE_SIZE << order) < 256 * sizeof(struct ip_rt_acct) * NR_CPUS; order++) 3129 /* NOTHING */; 3130 ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order); 3131 if (!ip_rt_acct) 3132 panic("IP: failed to allocate ip_rt_acct\n"); 3133 memset(ip_rt_acct, 0, PAGE_SIZE << order); 3134 } 3135 #endif 3136 3137 ipv4_dst_ops.kmem_cachep = 3138 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 3139 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); 3140 3141 rt_hash_table = (struct rt_hash_bucket *) 3142 alloc_large_system_hash("IP route cache", 3143 sizeof(struct rt_hash_bucket), 3144 rhash_entries, 3145 (num_physpages >= 128 * 1024) ? 3146 15 : 17, 3147 0, 3148 &rt_hash_log, 3149 &rt_hash_mask, 3150 0); 3151 memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket)); 3152 rt_hash_lock_init(); 3153 3154 ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1); 3155 ip_rt_max_size = (rt_hash_mask + 1) * 16; 3156 3157 devinet_init(); 3158 ip_fib_init(); 3159 3160 init_timer(&rt_flush_timer); 3161 rt_flush_timer.function = rt_run_flush; 3162 init_timer(&rt_periodic_timer); 3163 rt_periodic_timer.function = rt_check_expire; 3164 init_timer(&rt_secret_timer); 3165 rt_secret_timer.function = rt_secret_rebuild; 3166 3167 /* All the timers, started at system startup tend 3168 to synchronize. Perturb it a bit. 3169 */ 3170 rt_periodic_timer.expires = jiffies + net_random() % ip_rt_gc_interval + 3171 ip_rt_gc_interval; 3172 add_timer(&rt_periodic_timer); 3173 3174 rt_secret_timer.expires = jiffies + net_random() % ip_rt_secret_interval + 3175 ip_rt_secret_interval; 3176 add_timer(&rt_secret_timer); 3177 3178 #ifdef CONFIG_PROC_FS 3179 { 3180 struct proc_dir_entry *rtstat_pde = NULL; /* keep gcc happy */ 3181 if (!proc_net_fops_create("rt_cache", S_IRUGO, &rt_cache_seq_fops) || 3182 !(rtstat_pde = create_proc_entry("rt_cache", S_IRUGO, 3183 proc_net_stat))) { 3184 return -ENOMEM; 3185 } 3186 rtstat_pde->proc_fops = &rt_cpu_seq_fops; 3187 } 3188 #ifdef CONFIG_NET_CLS_ROUTE 3189 create_proc_read_entry("rt_acct", 0, proc_net, ip_rt_acct_read, NULL); 3190 #endif 3191 #endif 3192 #ifdef CONFIG_XFRM 3193 xfrm_init(); 3194 xfrm4_init(); 3195 #endif 3196 return rc; 3197 } 3198 3199 EXPORT_SYMBOL(__ip_select_ident); 3200 EXPORT_SYMBOL(ip_route_input); 3201 EXPORT_SYMBOL(ip_route_output_key); 3202