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   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/config.h>
  68 #include <linux/module.h>
  69 #include <asm/uaccess.h>
  70 #include <asm/system.h>
  71 #include <linux/bitops.h>
  72 #include <linux/types.h>
  73 #include <linux/kernel.h>
  74 #include <linux/sched.h>
  75 #include <linux/mm.h>
  76 #include <linux/bootmem.h>
  77 #include <linux/string.h>
  78 #include <linux/socket.h>
  79 #include <linux/sockios.h>
  80 #include <linux/errno.h>
  81 #include <linux/in.h>
  82 #include <linux/inet.h>
  83 #include <linux/netdevice.h>
  84 #include <linux/proc_fs.h>
  85 #include <linux/init.h>
  86 #include <linux/skbuff.h>
  87 #include <linux/rtnetlink.h>
  88 #include <linux/inetdevice.h>
  89 #include <linux/igmp.h>
  90 #include <linux/pkt_sched.h>
  91 #include <linux/mroute.h>
  92 #include <linux/netfilter_ipv4.h>
  93 #include <linux/random.h>
  94 #include <linux/jhash.h>
  95 #include <linux/rcupdate.h>
  96 #include <linux/times.h>
  97 #include <net/protocol.h>
  98 #include <net/ip.h>
  99 #include <net/route.h>
 100 #include <net/inetpeer.h>
 101 #include <net/sock.h>
 102 #include <net/ip_fib.h>
 103 #include <net/arp.h>
 104 #include <net/tcp.h>
 105 #include <net/icmp.h>
 106 #include <net/xfrm.h>
 107 #include <net/ip_mp_alg.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 /*
 211  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
 212  * The size of this table is a power of two and depends on the number of CPUS.
 213  */
 214 #if NR_CPUS >= 32
 215 #define RT_HASH_LOCK_SZ 4096
 216 #elif NR_CPUS >= 16
 217 #define RT_HASH_LOCK_SZ 2048
 218 #elif NR_CPUS >= 8
 219 #define RT_HASH_LOCK_SZ 1024
 220 #elif NR_CPUS >= 4
 221 #define RT_HASH_LOCK_SZ 512
 222 #else
 223 #define RT_HASH_LOCK_SZ 256
 224 #endif
 225
 226 static spinlock_t       *rt_hash_locks;
 227 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
 228 # define rt_hash_lock_init()    { \
 229                 int i; \
 230                 rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ, GFP_KERNEL); \
 231                 if (!rt_hash_locks) panic("IP: failed to allocate rt_hash_locks\n"); \
 232                 for (i = 0; i < RT_HASH_LOCK_SZ; i++) \
 233                         spin_lock_init(&rt_hash_locks[i]); \
 234                 }
 235 #else
 236 # define rt_hash_lock_addr(slot) NULL
 237 # define rt_hash_lock_init()
 238 #endif
 239
 240 static struct rt_hash_bucket    *rt_hash_table;
 241 static unsigned                 rt_hash_mask;
 242 static int                      rt_hash_log;
 243 static unsigned int             rt_hash_rnd;
 244
 245 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 246 #define RT_CACHE_STAT_INC(field) \
 247         (__raw_get_cpu_var(rt_cache_stat).field++)
 248
 249 static int rt_intern_hash(unsigned hash, struct rtable *rth,
 250                                 struct rtable **res);
 251
 252 static unsigned int rt_hash_code(u32 daddr, u32 saddr)
 253 {
 254         return (jhash_2words(daddr, saddr, rt_hash_rnd)
 255                 & rt_hash_mask);
 256 }
 257
 258 #ifdef CONFIG_PROC_FS
 259 struct rt_cache_iter_state {
 260         int bucket;
 261 };
 262
 263 static struct rtable *rt_cache_get_first(struct seq_file *seq)
 264 {
 265         struct rtable *r = NULL;
 266         struct rt_cache_iter_state *st = seq->private;
 267
 268         for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
 269                 rcu_read_lock_bh();
 270                 r = rt_hash_table[st->bucket].chain;
 271                 if (r)
 272                         break;
 273                 rcu_read_unlock_bh();
 274         }
 275         return r;
 276 }
 277
 278 static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
 279 {
 280         struct rt_cache_iter_state *st = rcu_dereference(seq->private);
 281
 282         r = r->u.rt_next;
 283         while (!r) {
 284                 rcu_read_unlock_bh();
 285                 if (--st->bucket < 0)
 286                         break;
 287                 rcu_read_lock_bh();
 288                 r = rt_hash_table[st->bucket].chain;
 289         }
 290         return r;
 291 }
 292
 293 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
 294 {
 295         struct rtable *r = rt_cache_get_first(seq);
 296
 297         if (r)
 298                 while (pos && (r = rt_cache_get_next(seq, r)))
 299                         --pos;
 300         return pos ? NULL : r;
 301 }
 302
 303 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 304 {
 305         return *pos ? rt_cache_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 306 }
 307
 308 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 309 {
 310         struct rtable *r = NULL;
 311
 312         if (v == SEQ_START_TOKEN)
 313                 r = rt_cache_get_first(seq);
 314         else
 315                 r = rt_cache_get_next(seq, v);
 316         ++*pos;
 317         return r;
 318 }
 319
 320 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 321 {
 322         if (v && v != SEQ_START_TOKEN)
 323                 rcu_read_unlock_bh();
 324 }
 325
 326 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 327 {
 328         if (v == SEQ_START_TOKEN)
 329                 seq_printf(seq, "%-127s\n",
 330                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 331                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 332                            "HHUptod\tSpecDst");
 333         else {
 334                 struct rtable *r = v;
 335                 char temp[256];
 336
 337                 sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
 338                               "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X",
 339                         r->u.dst.dev ? r->u.dst.dev->name : "*",
 340                         (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
 341                         r->rt_flags, atomic_read(&r->u.dst.__refcnt),
 342                         r->u.dst.__use, 0, (unsigned long)r->rt_src,
 343                         (dst_metric(&r->u.dst, RTAX_ADVMSS) ?
 344                              (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0),
 345                         dst_metric(&r->u.dst, RTAX_WINDOW),
 346                         (int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) +
 347                               dst_metric(&r->u.dst, RTAX_RTTVAR)),
 348                         r->fl.fl4_tos,
 349                         r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
 350                         r->u.dst.hh ? (r->u.dst.hh->hh_output ==
 351                                        dev_queue_xmit) : 0,
 352                         r->rt_spec_dst);
 353                 seq_printf(seq, "%-127s\n", temp);
 354         }
 355         return 0;
 356 }
 357
 358 static struct seq_operations rt_cache_seq_ops = {
 359         .start  = rt_cache_seq_start,
 360         .next   = rt_cache_seq_next,
 361         .stop   = rt_cache_seq_stop,
 362         .show   = rt_cache_seq_show,
 363 };
 364
 365 static int rt_cache_seq_open(struct inode *inode, struct file *file)
 366 {
 367         struct seq_file *seq;
 368         int rc = -ENOMEM;
 369         struct rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
 370
 371         if (!s)
 372                 goto out;
 373         rc = seq_open(file, &rt_cache_seq_ops);
 374         if (rc)
 375                 goto out_kfree;
 376         seq          = file->private_data;
 377         seq->private = s;
 378         memset(s, 0, sizeof(*s));
 379 out:
 380         return rc;
 381 out_kfree:
 382         kfree(s);
 383         goto out;
 384 }
 385
 386 static struct file_operations rt_cache_seq_fops = {
 387         .owner   = THIS_MODULE,
 388         .open    = rt_cache_seq_open,
 389         .read    = seq_read,
 390         .llseek  = seq_lseek,
 391         .release = seq_release_private,
 392 };
 393
 394
 395 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 396 {
 397         int cpu;
 398
 399         if (*pos == 0)
 400                 return SEQ_START_TOKEN;
 401
 402         for (cpu = *pos-1; cpu < NR_CPUS; ++cpu) {
 403                 if (!cpu_possible(cpu))
 404                         continue;
 405                 *pos = cpu+1;
 406                 return &per_cpu(rt_cache_stat, cpu);
 407         }
 408         return NULL;
 409 }
 410
 411 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 412 {
 413         int cpu;
 414
 415         for (cpu = *pos; cpu < NR_CPUS; ++cpu) {
 416                 if (!cpu_possible(cpu))
 417                         continue;
 418                 *pos = cpu+1;
 419                 return &per_cpu(rt_cache_stat, cpu);
 420         }
 421         return NULL;
 422
 423 }
 424
 425 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 426 {
 427
 428 }
 429
 430 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 431 {
 432         struct rt_cache_stat *st = v;
 433
 434         if (v == SEQ_START_TOKEN) {
 435                 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");
 436                 return 0;
 437         }
 438
 439         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 440                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
 441                    atomic_read(&ipv4_dst_ops.entries),
 442                    st->in_hit,
 443                    st->in_slow_tot,
 444                    st->in_slow_mc,
 445                    st->in_no_route,
 446                    st->in_brd,
 447                    st->in_martian_dst,
 448                    st->in_martian_src,
 449
 450                    st->out_hit,
 451                    st->out_slow_tot,
 452                    st->out_slow_mc,
 453
 454                    st->gc_total,
 455                    st->gc_ignored,
 456                    st->gc_goal_miss,
 457                    st->gc_dst_overflow,
 458                    st->in_hlist_search,
 459                    st->out_hlist_search
 460                 );
 461         return 0;
 462 }
 463
 464 static struct seq_operations rt_cpu_seq_ops = {
 465         .start  = rt_cpu_seq_start,
 466         .next   = rt_cpu_seq_next,
 467         .stop   = rt_cpu_seq_stop,
 468         .show   = rt_cpu_seq_show,
 469 };
 470
 471
 472 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 473 {
 474         return seq_open(file, &rt_cpu_seq_ops);
 475 }
 476
 477 static struct file_operations rt_cpu_seq_fops = {
 478         .owner   = THIS_MODULE,
 479         .open    = rt_cpu_seq_open,
 480         .read    = seq_read,
 481         .llseek  = seq_lseek,
 482         .release = seq_release,
 483 };
 484
 485 #endif /* CONFIG_PROC_FS */
 486
 487 static __inline__ void rt_free(struct rtable *rt)
 488 {
 489         multipath_remove(rt);
 490         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 491 }
 492
 493 static __inline__ void rt_drop(struct rtable *rt)
 494 {
 495         multipath_remove(rt);
 496         ip_rt_put(rt);
 497         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 498 }
 499
 500 static __inline__ int rt_fast_clean(struct rtable *rth)
 501 {
 502         /* Kill broadcast/multicast entries very aggresively, if they
 503            collide in hash table with more useful entries */
 504         return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
 505                 rth->fl.iif && rth->u.rt_next;
 506 }
 507
 508 static __inline__ int rt_valuable(struct rtable *rth)
 509 {
 510         return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
 511                 rth->u.dst.expires;
 512 }
 513
 514 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
 515 {
 516         unsigned long age;
 517         int ret = 0;
 518
 519         if (atomic_read(&rth->u.dst.__refcnt))
 520                 goto out;
 521
 522         ret = 1;
 523         if (rth->u.dst.expires &&
 524             time_after_eq(jiffies, rth->u.dst.expires))
 525                 goto out;
 526
 527         age = jiffies - rth->u.dst.lastuse;
 528         ret = 0;
 529         if ((age <= tmo1 && !rt_fast_clean(rth)) ||
 530             (age <= tmo2 && rt_valuable(rth)))
 531                 goto out;
 532         ret = 1;
 533 out:    return ret;
 534 }
 535
 536 /* Bits of score are:
 537  * 31: very valuable
 538  * 30: not quite useless
 539  * 29..0: usage counter
 540  */
 541 static inline u32 rt_score(struct rtable *rt)
 542 {
 543         u32 score = jiffies - rt->u.dst.lastuse;
 544
 545         score = ~score & ~(3<<30);
 546
 547         if (rt_valuable(rt))
 548                 score |= (1<<31);
 549
 550         if (!rt->fl.iif ||
 551             !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
 552                 score |= (1<<30);
 553
 554         return score;
 555 }
 556
 557 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 558 {
 559         return memcmp(&fl1->nl_u.ip4_u, &fl2->nl_u.ip4_u, sizeof(fl1->nl_u.ip4_u)) == 0 &&
 560                fl1->oif     == fl2->oif &&
 561                fl1->iif     == fl2->iif;
 562 }
 563
 564 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 565 static struct rtable **rt_remove_balanced_route(struct rtable **chain_head,
 566                                                 struct rtable *expentry,
 567                                                 int *removed_count)
 568 {
 569         int passedexpired = 0;
 570         struct rtable **nextstep = NULL;
 571         struct rtable **rthp = chain_head;
 572         struct rtable *rth;
 573
 574         if (removed_count)
 575                 *removed_count = 0;
 576
 577         while ((rth = *rthp) != NULL) {
 578                 if (rth == expentry)
 579                         passedexpired = 1;
 580
 581                 if (((*rthp)->u.dst.flags & DST_BALANCED) != 0  &&
 582                     compare_keys(&(*rthp)->fl, &expentry->fl)) {
 583                         if (*rthp == expentry) {
 584                                 *rthp = rth->u.rt_next;
 585                                 continue;
 586                         } else {
 587                                 *rthp = rth->u.rt_next;
 588                                 rt_free(rth);
 589                                 if (removed_count)
 590                                         ++(*removed_count);
 591                         }
 592                 } else {
 593                         if (!((*rthp)->u.dst.flags & DST_BALANCED) &&
 594                             passedexpired && !nextstep)
 595                                 nextstep = &rth->u.rt_next;
 596
 597                         rthp = &rth->u.rt_next;
 598                 }
 599         }
 600
 601         rt_free(expentry);
 602         if (removed_count)
 603                 ++(*removed_count);
 604
 605         return nextstep;
 606 }
 607 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 608
 609
 610 /* This runs via a timer and thus is always in BH context. */
 611 static void rt_check_expire(unsigned long dummy)
 612 {
 613         static unsigned int rover;
 614         unsigned int i = rover, goal;
 615         struct rtable *rth, **rthp;
 616         unsigned long now = jiffies;
 617         u64 mult;
 618
 619         mult = ((u64)ip_rt_gc_interval) << rt_hash_log;
 620         if (ip_rt_gc_timeout > 1)
 621                 do_div(mult, ip_rt_gc_timeout);
 622         goal = (unsigned int)mult;
 623         if (goal > rt_hash_mask) goal = rt_hash_mask + 1;
 624         for (; goal > 0; goal--) {
 625                 unsigned long tmo = ip_rt_gc_timeout;
 626
 627                 i = (i + 1) & rt_hash_mask;
 628                 rthp = &rt_hash_table[i].chain;
 629
 630                 if (*rthp == 0)
 631                         continue;
 632                 spin_lock(rt_hash_lock_addr(i));
 633                 while ((rth = *rthp) != NULL) {
 634                         if (rth->u.dst.expires) {
 635                                 /* Entry is expired even if it is in use */
 636                                 if (time_before_eq(now, rth->u.dst.expires)) {
 637                                         tmo >>= 1;
 638                                         rthp = &rth->u.rt_next;
 639                                         continue;
 640                                 }
 641                         } else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
 642                                 tmo >>= 1;
 643                                 rthp = &rth->u.rt_next;
 644                                 continue;
 645                         }
 646
 647                         /* Cleanup aged off entries. */
 648 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 649                         /* remove all related balanced entries if necessary */
 650                         if (rth->u.dst.flags & DST_BALANCED) {
 651                                 rthp = rt_remove_balanced_route(
 652                                         &rt_hash_table[i].chain,
 653                                         rth, NULL);
 654                                 if (!rthp)
 655                                         break;
 656                         } else {
 657                                 *rthp = rth->u.rt_next;
 658                                 rt_free(rth);
 659                         }
 660 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 661                         *rthp = rth->u.rt_next;
 662                         rt_free(rth);
 663 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 664                 }
 665                 spin_unlock(rt_hash_lock_addr(i));
 666
 667                 /* Fallback loop breaker. */
 668                 if (time_after(jiffies, now))
 669                         break;
 670         }
 671         rover = i;
 672         mod_timer(&rt_periodic_timer, jiffies + ip_rt_gc_interval);
 673 }
 674
 675 /* This can run from both BH and non-BH contexts, the latter
 676  * in the case of a forced flush event.
 677  */
 678 static void rt_run_flush(unsigned long dummy)
 679 {
 680         int i;
 681         struct rtable *rth, *next;
 682
 683         rt_deadline = 0;
 684
 685         get_random_bytes(&rt_hash_rnd, 4);
 686
 687         for (i = rt_hash_mask; i >= 0; i--) {
 688                 spin_lock_bh(rt_hash_lock_addr(i));
 689                 rth = rt_hash_table[i].chain;
 690                 if (rth)
 691                         rt_hash_table[i].chain = NULL;
 692                 spin_unlock_bh(rt_hash_lock_addr(i));
 693
 694                 for (; rth; rth = next) {
 695                         next = rth->u.rt_next;
 696                         rt_free(rth);
 697                 }
 698         }
 699 }
 700
 701 static DEFINE_SPINLOCK(rt_flush_lock);
 702
 703 void rt_cache_flush(int delay)
 704 {
 705         unsigned long now = jiffies;
 706         int user_mode = !in_softirq();
 707
 708         if (delay < 0)
 709                 delay = ip_rt_min_delay;
 710
 711         /* flush existing multipath state*/
 712         multipath_flush();
 713
 714         spin_lock_bh(&rt_flush_lock);
 715
 716         if (del_timer(&rt_flush_timer) && delay > 0 && rt_deadline) {
 717                 long tmo = (long)(rt_deadline - now);
 718
 719                 /* If flush timer is already running
 720                    and flush request is not immediate (delay > 0):
 721
 722                    if deadline is not achieved, prolongate timer to "delay",
 723                    otherwise fire it at deadline time.
 724                  */
 725
 726                 if (user_mode && tmo < ip_rt_max_delay-ip_rt_min_delay)
 727                         tmo = 0;
 728
 729                 if (delay > tmo)
 730                         delay = tmo;
 731         }
 732
 733         if (delay <= 0) {
 734                 spin_unlock_bh(&rt_flush_lock);
 735                 rt_run_flush(0);
 736                 return;
 737         }
 738
 739         if (rt_deadline == 0)
 740                 rt_deadline = now + ip_rt_max_delay;
 741
 742         mod_timer(&rt_flush_timer, now+delay);
 743         spin_unlock_bh(&rt_flush_lock);
 744 }
 745
 746 static void rt_secret_rebuild(unsigned long dummy)
 747 {
 748         unsigned long now = jiffies;
 749
 750         rt_cache_flush(0);
 751         mod_timer(&rt_secret_timer, now + ip_rt_secret_interval);
 752 }
 753
 754 /*
 755    Short description of GC goals.
 756
 757    We want to build algorithm, which will keep routing cache
 758    at some equilibrium point, when number of aged off entries
 759    is kept approximately equal to newly generated ones.
 760
 761    Current expiration strength is variable "expire".
 762    We try to adjust it dynamically, so that if networking
 763    is idle expires is large enough to keep enough of warm entries,
 764    and when load increases it reduces to limit cache size.
 765  */
 766
 767 static int rt_garbage_collect(void)
 768 {
 769         static unsigned long expire = RT_GC_TIMEOUT;
 770         static unsigned long last_gc;
 771         static int rover;
 772         static int equilibrium;
 773         struct rtable *rth, **rthp;
 774         unsigned long now = jiffies;
 775         int goal;
 776
 777         /*
 778          * Garbage collection is pretty expensive,
 779          * do not make it too frequently.
 780          */
 781
 782         RT_CACHE_STAT_INC(gc_total);
 783
 784         if (now - last_gc < ip_rt_gc_min_interval &&
 785             atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
 786                 RT_CACHE_STAT_INC(gc_ignored);
 787                 goto out;
 788         }
 789
 790         /* Calculate number of entries, which we want to expire now. */
 791         goal = atomic_read(&ipv4_dst_ops.entries) -
 792                 (ip_rt_gc_elasticity << rt_hash_log);
 793         if (goal <= 0) {
 794                 if (equilibrium < ipv4_dst_ops.gc_thresh)
 795                         equilibrium = ipv4_dst_ops.gc_thresh;
 796                 goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
 797                 if (goal > 0) {
 798                         equilibrium += min_t(unsigned int, goal / 2, rt_hash_mask + 1);
 799                         goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
 800                 }
 801         } else {
 802                 /* We are in dangerous area. Try to reduce cache really
 803                  * aggressively.
 804                  */
 805                 goal = max_t(unsigned int, goal / 2, rt_hash_mask + 1);
 806                 equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
 807         }
 808
 809         if (now - last_gc >= ip_rt_gc_min_interval)
 810                 last_gc = now;
 811
 812         if (goal <= 0) {
 813                 equilibrium += goal;
 814                 goto work_done;
 815         }
 816
 817         do {
 818                 int i, k;
 819
 820                 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
 821                         unsigned long tmo = expire;
 822
 823                         k = (k + 1) & rt_hash_mask;
 824                         rthp = &rt_hash_table[k].chain;
 825                         spin_lock_bh(rt_hash_lock_addr(k));
 826                         while ((rth = *rthp) != NULL) {
 827                                 if (!rt_may_expire(rth, tmo, expire)) {
 828                                         tmo >>= 1;
 829                                         rthp = &rth->u.rt_next;
 830                                         continue;
 831                                 }
 832 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 833                                 /* remove all related balanced entries
 834                                  * if necessary
 835                                  */
 836                                 if (rth->u.dst.flags & DST_BALANCED) {
 837                                         int r;
 838
 839                                         rthp = rt_remove_balanced_route(
 840                                                 &rt_hash_table[k].chain,
 841                                                 rth,
 842                                                 &r);
 843                                         goal -= r;
 844                                         if (!rthp)
 845                                                 break;
 846                                 } else {
 847                                         *rthp = rth->u.rt_next;
 848                                         rt_free(rth);
 849                                         goal--;
 850                                 }
 851 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 852                                 *rthp = rth->u.rt_next;
 853                                 rt_free(rth);
 854                                 goal--;
 855 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 856                         }
 857                         spin_unlock_bh(rt_hash_lock_addr(k));
 858                         if (goal <= 0)
 859                                 break;
 860                 }
 861                 rover = k;
 862
 863                 if (goal <= 0)
 864                         goto work_done;
 865
 866                 /* Goal is not achieved. We stop process if:
 867
 868                    - if expire reduced to zero. Otherwise, expire is halfed.
 869                    - if table is not full.
 870                    - if we are called from interrupt.
 871                    - jiffies check is just fallback/debug loop breaker.
 872                      We will not spin here for long time in any case.
 873                  */
 874
 875                 RT_CACHE_STAT_INC(gc_goal_miss);
 876
 877                 if (expire == 0)
 878                         break;
 879
 880                 expire >>= 1;
 881 #if RT_CACHE_DEBUG >= 2
 882                 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
 883                                 atomic_read(&ipv4_dst_ops.entries), goal, i);
 884 #endif
 885
 886                 if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
 887                         goto out;
 888         } while (!in_softirq() && time_before_eq(jiffies, now));
 889
 890         if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
 891                 goto out;
 892         if (net_ratelimit())
 893                 printk(KERN_WARNING "dst cache overflow\n");
 894         RT_CACHE_STAT_INC(gc_dst_overflow);
 895         return 1;
 896
 897 work_done:
 898         expire += ip_rt_gc_min_interval;
 899         if (expire > ip_rt_gc_timeout ||
 900             atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
 901                 expire = ip_rt_gc_timeout;
 902 #if RT_CACHE_DEBUG >= 2
 903         printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
 904                         atomic_read(&ipv4_dst_ops.entries), goal, rover);
 905 #endif
 906 out:    return 0;
 907 }
 908
 909 static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp)
 910 {
 911         struct rtable   *rth, **rthp;
 912         unsigned long   now;
 913         struct rtable *cand, **candp;
 914         u32             min_score;
 915         int             chain_length;
 916         int attempts = !in_softirq();
 917
 918 restart:
 919         chain_length = 0;
 920         min_score = ~(u32)0;
 921         cand = NULL;
 922         candp = NULL;
 923         now = jiffies;
 924
 925         rthp = &rt_hash_table[hash].chain;
 926
 927         spin_lock_bh(rt_hash_lock_addr(hash));
 928         while ((rth = *rthp) != NULL) {
 929 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 930                 if (!(rth->u.dst.flags & DST_BALANCED) &&
 931                     compare_keys(&rth->fl, &rt->fl)) {
 932 #else
 933                 if (compare_keys(&rth->fl, &rt->fl)) {
 934 #endif
 935                         /* Put it first */
 936                         *rthp = rth->u.rt_next;
 937                         /*
 938                          * Since lookup is lockfree, the deletion
 939                          * must be visible to another weakly ordered CPU before
 940                          * the insertion at the start of the hash chain.
 941                          */
 942                         rcu_assign_pointer(rth->u.rt_next,
 943                                            rt_hash_table[hash].chain);
 944                         /*
 945                          * Since lookup is lockfree, the update writes
 946                          * must be ordered for consistency on SMP.
 947                          */
 948                         rcu_assign_pointer(rt_hash_table[hash].chain, rth);
 949
 950                         rth->u.dst.__use++;
 951                         dst_hold(&rth->u.dst);
 952                         rth->u.dst.lastuse = now;
 953                         spin_unlock_bh(rt_hash_lock_addr(hash));
 954
 955                         rt_drop(rt);
 956                         *rp = rth;
 957                         return 0;
 958                 }
 959
 960                 if (!atomic_read(&rth->u.dst.__refcnt)) {
 961                         u32 score = rt_score(rth);
 962
 963                         if (score <= min_score) {
 964                                 cand = rth;
 965                                 candp = rthp;
 966                                 min_score = score;
 967                         }
 968                 }
 969
 970                 chain_length++;
 971
 972                 rthp = &rth->u.rt_next;
 973         }
 974
 975         if (cand) {
 976                 /* ip_rt_gc_elasticity used to be average length of chain
 977                  * length, when exceeded gc becomes really aggressive.
 978                  *
 979                  * The second limit is less certain. At the moment it allows
 980                  * only 2 entries per bucket. We will see.
 981                  */
 982                 if (chain_length > ip_rt_gc_elasticity) {
 983                         *candp = cand->u.rt_next;
 984                         rt_free(cand);
 985                 }
 986         }
 987
 988         /* Try to bind route to arp only if it is output
 989            route or unicast forwarding path.
 990          */
 991         if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
 992                 int err = arp_bind_neighbour(&rt->u.dst);
 993                 if (err) {
 994                         spin_unlock_bh(rt_hash_lock_addr(hash));
 995
 996                         if (err != -ENOBUFS) {
 997                                 rt_drop(rt);
 998                                 return err;
 999                         }
1000
1001                         /* Neighbour tables are full and nothing
1002                            can be released. Try to shrink route cache,
1003                            it is most likely it holds some neighbour records.
1004                          */
1005                         if (attempts-- > 0) {
1006                                 int saved_elasticity = ip_rt_gc_elasticity;
1007                                 int saved_int = ip_rt_gc_min_interval;
1008                                 ip_rt_gc_elasticity     = 1;
1009                                 ip_rt_gc_min_interval   = 0;
1010                                 rt_garbage_collect();
1011                                 ip_rt_gc_min_interval   = saved_int;
1012                                 ip_rt_gc_elasticity     = saved_elasticity;
1013                                 goto restart;
1014                         }
1015
1016                         if (net_ratelimit())
1017                                 printk(KERN_WARNING "Neighbour table overflow.\n");
1018                         rt_drop(rt);
1019                         return -ENOBUFS;
1020                 }
1021         }
1022
1023         rt->u.rt_next = rt_hash_table[hash].chain;
1024 #if RT_CACHE_DEBUG >= 2
1025         if (rt->u.rt_next) {
1026                 struct rtable *trt;
1027                 printk(KERN_DEBUG "rt_cache @%02x: %u.%u.%u.%u", hash,
1028                        NIPQUAD(rt->rt_dst));
1029                 for (trt = rt->u.rt_next; trt; trt = trt->u.rt_next)
1030                         printk(" . %u.%u.%u.%u", NIPQUAD(trt->rt_dst));
1031                 printk("\n");
1032         }
1033 #endif
1034         rt_hash_table[hash].chain = rt;
1035         spin_unlock_bh(rt_hash_lock_addr(hash));
1036         *rp = rt;
1037         return 0;
1038 }
1039
1040 void rt_bind_peer(struct rtable *rt, int create)
1041 {
1042         static DEFINE_SPINLOCK(rt_peer_lock);
1043         struct inet_peer *peer;
1044
1045         peer = inet_getpeer(rt->rt_dst, create);
1046
1047         spin_lock_bh(&rt_peer_lock);
1048         if (rt->peer == NULL) {
1049                 rt->peer = peer;
1050                 peer = NULL;
1051         }
1052         spin_unlock_bh(&rt_peer_lock);
1053         if (peer)
1054                 inet_putpeer(peer);
1055 }
1056
1057 /*
1058  * Peer allocation may fail only in serious out-of-memory conditions.  However
1059  * we still can generate some output.
1060  * Random ID selection looks a bit dangerous because we have no chances to
1061  * select ID being unique in a reasonable period of time.
1062  * But broken packet identifier may be better than no packet at all.
1063  */
1064 static void ip_select_fb_ident(struct iphdr *iph)
1065 {
1066         static DEFINE_SPINLOCK(ip_fb_id_lock);
1067         static u32 ip_fallback_id;
1068         u32 salt;
1069
1070         spin_lock_bh(&ip_fb_id_lock);
1071         salt = secure_ip_id(ip_fallback_id ^ iph->daddr);
1072         iph->id = htons(salt & 0xFFFF);
1073         ip_fallback_id = salt;
1074         spin_unlock_bh(&ip_fb_id_lock);
1075 }
1076
1077 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1078 {
1079         struct rtable *rt = (struct rtable *) dst;
1080
1081         if (rt) {
1082                 if (rt->peer == NULL)
1083                         rt_bind_peer(rt, 1);
1084
1085                 /* If peer is attached to destination, it is never detached,
1086                    so that we need not to grab a lock to dereference it.
1087                  */
1088                 if (rt->peer) {
1089                         iph->id = htons(inet_getid(rt->peer, more));
1090                         return;
1091                 }
1092         } else
1093                 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1094                        __builtin_return_address(0));
1095
1096         ip_select_fb_ident(iph);
1097 }
1098
1099 static void rt_del(unsigned hash, struct rtable *rt)
1100 {
1101         struct rtable **rthp;
1102
1103         spin_lock_bh(rt_hash_lock_addr(hash));
1104         ip_rt_put(rt);
1105         for (rthp = &rt_hash_table[hash].chain; *rthp;
1106              rthp = &(*rthp)->u.rt_next)
1107                 if (*rthp == rt) {
1108                         *rthp = rt->u.rt_next;
1109                         rt_free(rt);
1110                         break;
1111                 }
1112         spin_unlock_bh(rt_hash_lock_addr(hash));
1113 }
1114
1115 void ip_rt_redirect(u32 old_gw, u32 daddr, u32 new_gw,
1116                     u32 saddr, struct net_device *dev)
1117 {
1118         int i, k;
1119         struct in_device *in_dev = in_dev_get(dev);
1120         struct rtable *rth, **rthp;
1121         u32  skeys[2] = { saddr, 0 };
1122         int  ikeys[2] = { dev->ifindex, 0 };
1123
1124         if (!in_dev)
1125                 return;
1126
1127         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1128             || MULTICAST(new_gw) || BADCLASS(new_gw) || ZERONET(new_gw))
1129                 goto reject_redirect;
1130
1131         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1132                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1133                         goto reject_redirect;
1134                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1135                         goto reject_redirect;
1136         } else {
1137                 if (inet_addr_type(new_gw) != RTN_UNICAST)
1138                         goto reject_redirect;
1139         }
1140
1141         for (i = 0; i < 2; i++) {
1142                 for (k = 0; k < 2; k++) {
1143                         unsigned hash = rt_hash_code(daddr,
1144                                                      skeys[i] ^ (ikeys[k] << 5));
1145
1146                         rthp=&rt_hash_table[hash].chain;
1147
1148                         rcu_read_lock();
1149                         while ((rth = rcu_dereference(*rthp)) != NULL) {
1150                                 struct rtable *rt;
1151
1152                                 if (rth->fl.fl4_dst != daddr ||
1153                                     rth->fl.fl4_src != skeys[i] ||
1154                                     rth->fl.oif != ikeys[k] ||
1155                                     rth->fl.iif != 0) {
1156                                         rthp = &rth->u.rt_next;
1157                                         continue;
1158                                 }
1159
1160                                 if (rth->rt_dst != daddr ||
1161                                     rth->rt_src != saddr ||
1162                                     rth->u.dst.error ||
1163                                     rth->rt_gateway != old_gw ||
1164                                     rth->u.dst.dev != dev)
1165                                         break;
1166
1167                                 dst_hold(&rth->u.dst);
1168                                 rcu_read_unlock();
1169
1170                                 rt = dst_alloc(&ipv4_dst_ops);
1171                                 if (rt == NULL) {
1172                                         ip_rt_put(rth);
1173                                         in_dev_put(in_dev);
1174                                         return;
1175                                 }
1176
1177                                 /* Copy all the information. */
1178                                 *rt = *rth;
1179                                 INIT_RCU_HEAD(&rt->u.dst.rcu_head);
1180                                 rt->u.dst.__use         = 1;
1181                                 atomic_set(&rt->u.dst.__refcnt, 1);
1182                                 rt->u.dst.child         = NULL;
1183                                 if (rt->u.dst.dev)
1184                                         dev_hold(rt->u.dst.dev);
1185                                 if (rt->idev)
1186                                         in_dev_hold(rt->idev);
1187                                 rt->u.dst.obsolete      = 0;
1188                                 rt->u.dst.lastuse       = jiffies;
1189                                 rt->u.dst.path          = &rt->u.dst;
1190                                 rt->u.dst.neighbour     = NULL;
1191                                 rt->u.dst.hh            = NULL;
1192                                 rt->u.dst.xfrm          = NULL;
1193
1194                                 rt->rt_flags            |= RTCF_REDIRECTED;
1195
1196                                 /* Gateway is different ... */
1197                                 rt->rt_gateway          = new_gw;
1198
1199                                 /* Redirect received -> path was valid */
1200                                 dst_confirm(&rth->u.dst);
1201
1202                                 if (rt->peer)
1203                                         atomic_inc(&rt->peer->refcnt);
1204
1205                                 if (arp_bind_neighbour(&rt->u.dst) ||
1206                                     !(rt->u.dst.neighbour->nud_state &
1207                                             NUD_VALID)) {
1208                                         if (rt->u.dst.neighbour)
1209                                                 neigh_event_send(rt->u.dst.neighbour, NULL);
1210                                         ip_rt_put(rth);
1211                                         rt_drop(rt);
1212                                         goto do_next;
1213                                 }
1214
1215                                 rt_del(hash, rth);
1216                                 if (!rt_intern_hash(hash, rt, &rt))
1217                                         ip_rt_put(rt);
1218                                 goto do_next;
1219                         }
1220                         rcu_read_unlock();
1221                 do_next:
1222                         ;
1223                 }
1224         }
1225         in_dev_put(in_dev);
1226         return;
1227
1228 reject_redirect:
1229 #ifdef CONFIG_IP_ROUTE_VERBOSE
1230         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1231                 printk(KERN_INFO "Redirect from %u.%u.%u.%u on %s about "
1232                         "%u.%u.%u.%u ignored.\n"
1233                         "  Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n",
1234                        NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1235                        NIPQUAD(saddr), NIPQUAD(daddr));
1236 #endif
1237         in_dev_put(in_dev);
1238 }
1239
1240 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1241 {
1242         struct rtable *rt = (struct rtable*)dst;
1243         struct dst_entry *ret = dst;
1244
1245         if (rt) {
1246                 if (dst->obsolete) {
1247                         ip_rt_put(rt);
1248                         ret = NULL;
1249                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1250                            rt->u.dst.expires) {
1251                         unsigned hash = rt_hash_code(rt->fl.fl4_dst,
1252                                                      rt->fl.fl4_src ^
1253                                                         (rt->fl.oif << 5));
1254 #if RT_CACHE_DEBUG >= 1
1255                         printk(KERN_DEBUG "ip_rt_advice: redirect to "
1256                                           "%u.%u.%u.%u/%02x dropped\n",
1257                                 NIPQUAD(rt->rt_dst), rt->fl.fl4_tos);
1258 #endif
1259                         rt_del(hash, rt);
1260                         ret = NULL;
1261                 }
1262         }
1263         return ret;
1264 }
1265
1266 /*
1267  * Algorithm:
1268  *      1. The first ip_rt_redirect_number redirects are sent
1269  *         with exponential backoff, then we stop sending them at all,
1270  *         assuming that the host ignores our redirects.
1271  *      2. If we did not see packets requiring redirects
1272  *         during ip_rt_redirect_silence, we assume that the host
1273  *         forgot redirected route and start to send redirects again.
1274  *
1275  * This algorithm is much cheaper and more intelligent than dumb load limiting
1276  * in icmp.c.
1277  *
1278  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1279  * and "frag. need" (breaks PMTU discovery) in icmp.c.
1280  */
1281
1282 void ip_rt_send_redirect(struct sk_buff *skb)
1283 {
1284         struct rtable *rt = (struct rtable*)skb->dst;
1285         struct in_device *in_dev = in_dev_get(rt->u.dst.dev);
1286
1287         if (!in_dev)
1288                 return;
1289
1290         if (!IN_DEV_TX_REDIRECTS(in_dev))
1291                 goto out;
1292
1293         /* No redirected packets during ip_rt_redirect_silence;
1294          * reset the algorithm.
1295          */
1296         if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence))
1297                 rt->u.dst.rate_tokens = 0;
1298
1299         /* Too many ignored redirects; do not send anything
1300          * set u.dst.rate_last to the last seen redirected packet.
1301          */
1302         if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) {
1303                 rt->u.dst.rate_last = jiffies;
1304                 goto out;
1305         }
1306
1307         /* Check for load limit; set rate_last to the latest sent
1308          * redirect.
1309          */
1310         if (time_after(jiffies,
1311                        (rt->u.dst.rate_last +
1312                         (ip_rt_redirect_load << rt->u.dst.rate_tokens)))) {
1313                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1314                 rt->u.dst.rate_last = jiffies;
1315                 ++rt->u.dst.rate_tokens;
1316 #ifdef CONFIG_IP_ROUTE_VERBOSE
1317                 if (IN_DEV_LOG_MARTIANS(in_dev) &&
1318                     rt->u.dst.rate_tokens == ip_rt_redirect_number &&
1319                     net_ratelimit())
1320                         printk(KERN_WARNING "host %u.%u.%u.%u/if%d ignores "
1321                                 "redirects for %u.%u.%u.%u to %u.%u.%u.%u.\n",
1322                                 NIPQUAD(rt->rt_src), rt->rt_iif,
1323                                 NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_gateway));
1324 #endif
1325         }
1326 out:
1327         in_dev_put(in_dev);
1328 }
1329
1330 static int ip_error(struct sk_buff *skb)
1331 {
1332         struct rtable *rt = (struct rtable*)skb->dst;
1333         unsigned long now;
1334         int code;
1335
1336         switch (rt->u.dst.error) {
1337                 case EINVAL:
1338                 default:
1339                         goto out;
1340                 case EHOSTUNREACH:
1341                         code = ICMP_HOST_UNREACH;
1342                         break;
1343                 case ENETUNREACH:
1344                         code = ICMP_NET_UNREACH;
1345                         break;
1346                 case EACCES:
1347                         code = ICMP_PKT_FILTERED;
1348                         break;
1349         }
1350
1351         now = jiffies;
1352         rt->u.dst.rate_tokens += now - rt->u.dst.rate_last;
1353         if (rt->u.dst.rate_tokens > ip_rt_error_burst)
1354                 rt->u.dst.rate_tokens = ip_rt_error_burst;
1355         rt->u.dst.rate_last = now;
1356         if (rt->u.dst.rate_tokens >= ip_rt_error_cost) {
1357                 rt->u.dst.rate_tokens -= ip_rt_error_cost;
1358                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1359         }
1360
1361 out:    kfree_skb(skb);
1362         return 0;
1363 }
1364
1365 /*
1366  *      The last two values are not from the RFC but
1367  *      are needed for AMPRnet AX.25 paths.
1368  */
1369
1370 static const unsigned short mtu_plateau[] =
1371 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1372
1373 static __inline__ unsigned short guess_mtu(unsigned short old_mtu)
1374 {
1375         int i;
1376
1377         for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1378                 if (old_mtu > mtu_plateau[i])
1379                         return mtu_plateau[i];
1380         return 68;
1381 }
1382
1383 unsigned short ip_rt_frag_needed(struct iphdr *iph, unsigned short new_mtu)
1384 {
1385         int i;
1386         unsigned short old_mtu = ntohs(iph->tot_len);
1387         struct rtable *rth;
1388         u32  skeys[2] = { iph->saddr, 0, };
1389         u32  daddr = iph->daddr;
1390         unsigned short est_mtu = 0;
1391
1392         if (ipv4_config.no_pmtu_disc)
1393                 return 0;
1394
1395         for (i = 0; i < 2; i++) {
1396                 unsigned hash = rt_hash_code(daddr, skeys[i]);
1397
1398                 rcu_read_lock();
1399                 for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1400                      rth = rcu_dereference(rth->u.rt_next)) {
1401                         if (rth->fl.fl4_dst == daddr &&
1402                             rth->fl.fl4_src == skeys[i] &&
1403                             rth->rt_dst  == daddr &&
1404                             rth->rt_src  == iph->saddr &&
1405                             rth->fl.iif == 0 &&
1406                             !(dst_metric_locked(&rth->u.dst, RTAX_MTU))) {
1407                                 unsigned short mtu = new_mtu;
1408
1409                                 if (new_mtu < 68 || new_mtu >= old_mtu) {
1410
1411                                         /* BSD 4.2 compatibility hack :-( */
1412                                         if (mtu == 0 &&
1413                                             old_mtu >= rth->u.dst.metrics[RTAX_MTU-1] &&
1414                                             old_mtu >= 68 + (iph->ihl << 2))
1415                                                 old_mtu -= iph->ihl << 2;
1416
1417                                         mtu = guess_mtu(old_mtu);
1418                                 }
1419                                 if (mtu <= rth->u.dst.metrics[RTAX_MTU-1]) {
1420                                         if (mtu < rth->u.dst.metrics[RTAX_MTU-1]) {
1421                                                 dst_confirm(&rth->u.dst);
1422                                                 if (mtu < ip_rt_min_pmtu) {
1423                                                         mtu = ip_rt_min_pmtu;
1424                                                         rth->u.dst.metrics[RTAX_LOCK-1] |=
1425                                                                 (1 << RTAX_MTU);
1426                                                 }
1427                                                 rth->u.dst.metrics[RTAX_MTU-1] = mtu;
1428                                                 dst_set_expires(&rth->u.dst,
1429                                                         ip_rt_mtu_expires);
1430                                         }
1431                                         est_mtu = mtu;
1432                                 }
1433                         }
1434                 }
1435                 rcu_read_unlock();
1436         }
1437         return est_mtu ? : new_mtu;
1438 }
1439
1440 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1441 {
1442         if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= 68 &&
1443             !(dst_metric_locked(dst, RTAX_MTU))) {
1444                 if (mtu < ip_rt_min_pmtu) {
1445                         mtu = ip_rt_min_pmtu;
1446                         dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU);
1447                 }
1448                 dst->metrics[RTAX_MTU-1] = mtu;
1449                 dst_set_expires(dst, ip_rt_mtu_expires);
1450         }
1451 }
1452
1453 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1454 {
1455         return NULL;
1456 }
1457
1458 static void ipv4_dst_destroy(struct dst_entry *dst)
1459 {
1460         struct rtable *rt = (struct rtable *) dst;
1461         struct inet_peer *peer = rt->peer;
1462         struct in_device *idev = rt->idev;
1463
1464         if (peer) {
1465                 rt->peer = NULL;
1466                 inet_putpeer(peer);
1467         }
1468
1469         if (idev) {
1470                 rt->idev = NULL;
1471                 in_dev_put(idev);
1472         }
1473 }
1474
1475 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
1476                             int how)
1477 {
1478         struct rtable *rt = (struct rtable *) dst;
1479         struct in_device *idev = rt->idev;
1480         if (dev != &loopback_dev && idev && idev->dev == dev) {
1481                 struct in_device *loopback_idev = in_dev_get(&loopback_dev);
1482                 if (loopback_idev) {
1483                         rt->idev = loopback_idev;
1484                         in_dev_put(idev);
1485                 }
1486         }
1487 }
1488
1489 static void ipv4_link_failure(struct sk_buff *skb)
1490 {
1491         struct rtable *rt;
1492
1493         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1494
1495         rt = (struct rtable *) skb->dst;
1496         if (rt)
1497                 dst_set_expires(&rt->u.dst, 0);
1498 }
1499
1500 static int ip_rt_bug(struct sk_buff *skb)
1501 {
1502         printk(KERN_DEBUG "ip_rt_bug: %u.%u.%u.%u -> %u.%u.%u.%u, %s\n",
1503                 NIPQUAD(skb->nh.iph->saddr), NIPQUAD(skb->nh.iph->daddr),
1504                 skb->dev ? skb->dev->name : "?");
1505         kfree_skb(skb);
1506         return 0;
1507 }
1508
1509 /*
1510    We do not cache source address of outgoing interface,
1511    because it is used only by IP RR, TS and SRR options,
1512    so that it out of fast path.
1513
1514    BTW remember: "addr" is allowed to be not aligned
1515    in IP options!
1516  */
1517
1518 void ip_rt_get_source(u8 *addr, struct rtable *rt)
1519 {
1520         u32 src;
1521         struct fib_result res;
1522
1523         if (rt->fl.iif == 0)
1524                 src = rt->rt_src;
1525         else if (fib_lookup(&rt->fl, &res) == 0) {
1526                 src = FIB_RES_PREFSRC(res);
1527                 fib_res_put(&res);
1528         } else
1529                 src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
1530                                         RT_SCOPE_UNIVERSE);
1531         memcpy(addr, &src, 4);
1532 }
1533
1534 #ifdef CONFIG_NET_CLS_ROUTE
1535 static void set_class_tag(struct rtable *rt, u32 tag)
1536 {
1537         if (!(rt->u.dst.tclassid & 0xFFFF))
1538                 rt->u.dst.tclassid |= tag & 0xFFFF;
1539         if (!(rt->u.dst.tclassid & 0xFFFF0000))
1540                 rt->u.dst.tclassid |= tag & 0xFFFF0000;
1541 }
1542 #endif
1543
1544 static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
1545 {
1546         struct fib_info *fi = res->fi;
1547
1548         if (fi) {
1549                 if (FIB_RES_GW(*res) &&
1550                     FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1551                         rt->rt_gateway = FIB_RES_GW(*res);
1552                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
1553                        sizeof(rt->u.dst.metrics));
1554                 if (fi->fib_mtu == 0) {
1555                         rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
1556                         if (rt->u.dst.metrics[RTAX_LOCK-1] & (1 << RTAX_MTU) &&
1557                             rt->rt_gateway != rt->rt_dst &&
1558                             rt->u.dst.dev->mtu > 576)
1559                                 rt->u.dst.metrics[RTAX_MTU-1] = 576;
1560                 }
1561 #ifdef CONFIG_NET_CLS_ROUTE
1562                 rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1563 #endif
1564         } else
1565                 rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;
1566
1567         if (rt->u.dst.metrics[RTAX_HOPLIMIT-1] == 0)
1568                 rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
1569         if (rt->u.dst.metrics[RTAX_MTU-1] > IP_MAX_MTU)
1570                 rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
1571         if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0)
1572                 rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
1573                                        ip_rt_min_advmss);
1574         if (rt->u.dst.metrics[RTAX_ADVMSS-1] > 65535 - 40)
1575                 rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;
1576
1577 #ifdef CONFIG_NET_CLS_ROUTE
1578 #ifdef CONFIG_IP_MULTIPLE_TABLES
1579         set_class_tag(rt, fib_rules_tclass(res));
1580 #endif
1581         set_class_tag(rt, itag);
1582 #endif
1583         rt->rt_type = res->type;
1584 }
1585
1586 static int ip_route_input_mc(struct sk_buff *skb, u32 daddr, u32 saddr,
1587                                 u8 tos, struct net_device *dev, int our)
1588 {
1589         unsigned hash;
1590         struct rtable *rth;
1591         u32 spec_dst;
1592         struct in_device *in_dev = in_dev_get(dev);
1593         u32 itag = 0;
1594
1595         /* Primary sanity checks. */
1596
1597         if (in_dev == NULL)
1598                 return -EINVAL;
1599
1600         if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr) ||
1601             skb->protocol != htons(ETH_P_IP))
1602                 goto e_inval;
1603
1604         if (ZERONET(saddr)) {
1605                 if (!LOCAL_MCAST(daddr))
1606                         goto e_inval;
1607                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1608         } else if (fib_validate_source(saddr, 0, tos, 0,
1609                                         dev, &spec_dst, &itag) < 0)
1610                 goto e_inval;
1611
1612         rth = dst_alloc(&ipv4_dst_ops);
1613         if (!rth)
1614                 goto e_nobufs;
1615
1616         rth->u.dst.output= ip_rt_bug;
1617
1618         atomic_set(&rth->u.dst.__refcnt, 1);
1619         rth->u.dst.flags= DST_HOST;
1620         if (in_dev->cnf.no_policy)
1621                 rth->u.dst.flags |= DST_NOPOLICY;
1622         rth->fl.fl4_dst = daddr;
1623         rth->rt_dst     = daddr;
1624         rth->fl.fl4_tos = tos;
1625 #ifdef CONFIG_IP_ROUTE_FWMARK
1626         rth->fl.fl4_fwmark= skb->nfmark;
1627 #endif
1628         rth->fl.fl4_src = saddr;
1629         rth->rt_src     = saddr;
1630 #ifdef CONFIG_NET_CLS_ROUTE
1631         rth->u.dst.tclassid = itag;
1632 #endif
1633         rth->rt_iif     =
1634         rth->fl.iif     = dev->ifindex;
1635         rth->u.dst.dev  = &loopback_dev;
1636         dev_hold(rth->u.dst.dev);
1637         rth->idev       = in_dev_get(rth->u.dst.dev);
1638         rth->fl.oif     = 0;
1639         rth->rt_gateway = daddr;
1640         rth->rt_spec_dst= spec_dst;
1641         rth->rt_type    = RTN_MULTICAST;
1642         rth->rt_flags   = RTCF_MULTICAST;
1643         if (our) {
1644                 rth->u.dst.input= ip_local_deliver;
1645                 rth->rt_flags |= RTCF_LOCAL;
1646         }
1647
1648 #ifdef CONFIG_IP_MROUTE
1649         if (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
1650                 rth->u.dst.input = ip_mr_input;
1651 #endif
1652         RT_CACHE_STAT_INC(in_slow_mc);
1653
1654         in_dev_put(in_dev);
1655         hash = rt_hash_code(daddr, saddr ^ (dev->ifindex << 5));
1656         return rt_intern_hash(hash, rth, (struct rtable**) &skb->dst);
1657
1658 e_nobufs:
1659         in_dev_put(in_dev);
1660         return -ENOBUFS;
1661
1662 e_inval:
1663         in_dev_put(in_dev);
1664         return -EINVAL;
1665 }
1666
1667
1668 static void ip_handle_martian_source(struct net_device *dev,
1669                                      struct in_device *in_dev,
1670                                      struct sk_buff *skb,
1671                                      u32 daddr,
1672                                      u32 saddr)
1673 {
1674         RT_CACHE_STAT_INC(in_martian_src);
1675 #ifdef CONFIG_IP_ROUTE_VERBOSE
1676         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1677                 /*
1678                  *      RFC1812 recommendation, if source is martian,
1679                  *      the only hint is MAC header.
1680                  */
1681                 printk(KERN_WARNING "martian source %u.%u.%u.%u from "
1682                         "%u.%u.%u.%u, on dev %s\n",
1683                         NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
1684                 if (dev->hard_header_len && skb->mac.raw) {
1685                         int i;
1686                         unsigned char *p = skb->mac.raw;
1687                         printk(KERN_WARNING "ll header: ");
1688                         for (i = 0; i < dev->hard_header_len; i++, p++) {
1689                                 printk("%02x", *p);
1690                                 if (i < (dev->hard_header_len - 1))
1691                                         printk(":");
1692                         }
1693                         printk("\n");
1694                 }
1695         }
1696 #endif
1697 }
1698
1699 static inline int __mkroute_input(struct sk_buff *skb,
1700                                   struct fib_result* res,
1701                                   struct in_device *in_dev,
1702                                   u32 daddr, u32 saddr, u32 tos,
1703                                   struct rtable **result)
1704 {
1705
1706         struct rtable *rth;
1707         int err;
1708         struct in_device *out_dev;
1709         unsigned flags = 0;
1710         u32 spec_dst, itag;
1711
1712         /* get a working reference to the output device */
1713         out_dev = in_dev_get(FIB_RES_DEV(*res));
1714         if (out_dev == NULL) {
1715                 if (net_ratelimit())
1716                         printk(KERN_CRIT "Bug in ip_route_input" \
1717                                "_slow(). Please, report\n");
1718                 return -EINVAL;
1719         }
1720
1721
1722         err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
1723                                   in_dev->dev, &spec_dst, &itag);
1724         if (err < 0) {
1725                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1726                                          saddr);
1727
1728                 err = -EINVAL;
1729                 goto cleanup;
1730         }
1731
1732         if (err)
1733                 flags |= RTCF_DIRECTSRC;
1734
1735         if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
1736             (IN_DEV_SHARED_MEDIA(out_dev) ||
1737              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1738                 flags |= RTCF_DOREDIRECT;
1739
1740         if (skb->protocol != htons(ETH_P_IP)) {
1741                 /* Not IP (i.e. ARP). Do not create route, if it is
1742                  * invalid for proxy arp. DNAT routes are always valid.
1743                  */
1744                 if (out_dev == in_dev && !(flags & RTCF_DNAT)) {
1745                         err = -EINVAL;
1746                         goto cleanup;
1747                 }
1748         }
1749
1750
1751         rth = dst_alloc(&ipv4_dst_ops);
1752         if (!rth) {
1753                 err = -ENOBUFS;
1754                 goto cleanup;
1755         }
1756
1757         atomic_set(&rth->u.dst.__refcnt, 1);
1758         rth->u.dst.flags= DST_HOST;
1759 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
1760         if (res->fi->fib_nhs > 1)
1761                 rth->u.dst.flags |= DST_BALANCED;
1762 #endif
1763         if (in_dev->cnf.no_policy)
1764                 rth->u.dst.flags |= DST_NOPOLICY;
1765         if (in_dev->cnf.no_xfrm)
1766                 rth->u.dst.flags |= DST_NOXFRM;
1767         rth->fl.fl4_dst = daddr;
1768         rth->rt_dst     = daddr;
1769         rth->fl.fl4_tos = tos;
1770 #ifdef CONFIG_IP_ROUTE_FWMARK
1771         rth->fl.fl4_fwmark= skb->nfmark;
1772 #endif
1773         rth->fl.fl4_src = saddr;
1774         rth->rt_src     = saddr;
1775         rth->rt_gateway = daddr;
1776         rth->rt_iif     =
1777                 rth->fl.iif     = in_dev->dev->ifindex;
1778         rth->u.dst.dev  = (out_dev)->dev;
1779         dev_hold(rth->u.dst.dev);
1780         rth->idev       = in_dev_get(rth->u.dst.dev);
1781         rth->fl.oif     = 0;
1782         rth->rt_spec_dst= spec_dst;
1783
1784         rth->u.dst.input = ip_forward;
1785         rth->u.dst.output = ip_output;
1786
1787         rt_set_nexthop(rth, res, itag);
1788
1789         rth->rt_flags = flags;
1790
1791         *result = rth;
1792         err = 0;
1793  cleanup:
1794         /* release the working reference to the output device */
1795         in_dev_put(out_dev);
1796         return err;
1797 }
1798
1799 static inline int ip_mkroute_input_def(struct sk_buff *skb,
1800                                        struct fib_result* res,
1801                                        const struct flowi *fl,
1802                                        struct in_device *in_dev,
1803                                        u32 daddr, u32 saddr, u32 tos)
1804 {
1805         struct rtable* rth = NULL;
1806         int err;
1807         unsigned hash;
1808
1809 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1810         if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0)
1811                 fib_select_multipath(fl, res);
1812 #endif
1813
1814         /* create a routing cache entry */
1815         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1816         if (err)
1817                 return err;
1818
1819         /* put it into the cache */
1820         hash = rt_hash_code(daddr, saddr ^ (fl->iif << 5));
1821         return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
1822 }
1823
1824 static inline int ip_mkroute_input(struct sk_buff *skb,
1825                                    struct fib_result* res,
1826                                    const struct flowi *fl,
1827                                    struct in_device *in_dev,
1828                                    u32 daddr, u32 saddr, u32 tos)
1829 {
1830 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
1831         struct rtable* rth = NULL, *rtres;
1832         unsigned char hop, hopcount;
1833         int err = -EINVAL;
1834         unsigned int hash;
1835
1836         if (res->fi)
1837                 hopcount = res->fi->fib_nhs;
1838         else
1839                 hopcount = 1;
1840
1841         /* distinguish between multipath and singlepath */
1842         if (hopcount < 2)
1843                 return ip_mkroute_input_def(skb, res, fl, in_dev, daddr,
1844                                             saddr, tos);
1845
1846         /* add all alternatives to the routing cache */
1847         for (hop = 0; hop < hopcount; hop++) {
1848                 res->nh_sel = hop;
1849
1850                 /* put reference to previous result */
1851                 if (hop)
1852                         ip_rt_put(rtres);
1853
1854                 /* create a routing cache entry */
1855                 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos,
1856                                       &rth);
1857                 if (err)
1858                         return err;
1859
1860                 /* put it into the cache */
1861                 hash = rt_hash_code(daddr, saddr ^ (fl->iif << 5));
1862                 err = rt_intern_hash(hash, rth, &rtres);
1863                 if (err)
1864                         return err;
1865
1866                 /* forward hop information to multipath impl. */
1867                 multipath_set_nhinfo(rth,
1868                                      FIB_RES_NETWORK(*res),
1869                                      FIB_RES_NETMASK(*res),
1870                                      res->prefixlen,
1871                                      &FIB_RES_NH(*res));
1872         }
1873         skb->dst = &rtres->u.dst;
1874         return err;
1875 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED  */
1876         return ip_mkroute_input_def(skb, res, fl, in_dev, daddr, saddr, tos);
1877 #endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED  */
1878 }
1879
1880
1881 /*
1882  *      NOTE. We drop all the packets that has local source
1883  *      addresses, because every properly looped back packet
1884  *      must have correct destination already attached by output routine.
1885  *
1886  *      Such approach solves two big problems:
1887  *      1. Not simplex devices are handled properly.
1888  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1889  */
1890
1891 static int ip_route_input_slow(struct sk_buff *skb, u32 daddr, u32 saddr,
1892                                u8 tos, struct net_device *dev)
1893 {
1894         struct fib_result res;
1895         struct in_device *in_dev = in_dev_get(dev);
1896         struct flowi fl = { .nl_u = { .ip4_u =
1897                                       { .daddr = daddr,
1898                                         .saddr = saddr,
1899                                         .tos = tos,
1900                                         .scope = RT_SCOPE_UNIVERSE,
1901 #ifdef CONFIG_IP_ROUTE_FWMARK
1902                                         .fwmark = skb->nfmark
1903 #endif
1904                                       } },
1905                             .iif = dev->ifindex };
1906         unsigned        flags = 0;
1907         u32             itag = 0;
1908         struct rtable * rth;
1909         unsigned        hash;
1910         u32             spec_dst;
1911         int             err = -EINVAL;
1912         int             free_res = 0;
1913
1914         /* IP on this device is disabled. */
1915
1916         if (!in_dev)
1917                 goto out;
1918
1919         /* Check for the most weird martians, which can be not detected
1920            by fib_lookup.
1921          */
1922
1923         if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr))
1924                 goto martian_source;
1925
1926         if (daddr == 0xFFFFFFFF || (saddr == 0 && daddr == 0))
1927                 goto brd_input;
1928
1929         /* Accept zero addresses only to limited broadcast;
1930          * I even do not know to fix it or not. Waiting for complains :-)
1931          */
1932         if (ZERONET(saddr))
1933                 goto martian_source;
1934
1935         if (BADCLASS(daddr) || ZERONET(daddr) || LOOPBACK(daddr))
1936                 goto martian_destination;
1937
1938         /*
1939          *      Now we are ready to route packet.
1940          */
1941         if ((err = fib_lookup(&fl, &res)) != 0) {
1942                 if (!IN_DEV_FORWARD(in_dev))
1943                         goto e_hostunreach;
1944                 goto no_route;
1945         }
1946         free_res = 1;
1947
1948         RT_CACHE_STAT_INC(in_slow_tot);
1949
1950         if (res.type == RTN_BROADCAST)
1951                 goto brd_input;
1952
1953         if (res.type == RTN_LOCAL) {
1954                 int result;
1955                 result = fib_validate_source(saddr, daddr, tos,
1956                                              loopback_dev.ifindex,
1957                                              dev, &spec_dst, &itag);
1958                 if (result < 0)
1959                         goto martian_source;
1960                 if (result)
1961                         flags |= RTCF_DIRECTSRC;
1962                 spec_dst = daddr;
1963                 goto local_input;
1964         }
1965
1966         if (!IN_DEV_FORWARD(in_dev))
1967                 goto e_hostunreach;
1968         if (res.type != RTN_UNICAST)
1969                 goto martian_destination;
1970
1971         err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
1972         if (err == -ENOBUFS)
1973                 goto e_nobufs;
1974         if (err == -EINVAL)
1975                 goto e_inval;
1976
1977 done:
1978         in_dev_put(in_dev);
1979         if (free_res)
1980                 fib_res_put(&res);
1981 out:    return err;
1982
1983 brd_input:
1984         if (skb->protocol != htons(ETH_P_IP))
1985                 goto e_inval;
1986
1987         if (ZERONET(saddr))
1988                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1989         else {
1990                 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
1991                                           &itag);
1992                 if (err < 0)
1993                         goto martian_source;
1994                 if (err)
1995                         flags |= RTCF_DIRECTSRC;
1996         }
1997         flags |= RTCF_BROADCAST;
1998         res.type = RTN_BROADCAST;
1999         RT_CACHE_STAT_INC(in_brd);
2000
2001 local_input:
2002         rth = dst_alloc(&ipv4_dst_ops);
2003         if (!rth)
2004                 goto e_nobufs;
2005
2006         rth->u.dst.output= ip_rt_bug;
2007
2008         atomic_set(&rth->u.dst.__refcnt, 1);
2009         rth->u.dst.flags= DST_HOST;
2010         if (in_dev->cnf.no_policy)
2011                 rth->u.dst.flags |= DST_NOPOLICY;
2012         rth->fl.fl4_dst = daddr;
2013         rth->rt_dst     = daddr;
2014         rth->fl.fl4_tos = tos;
2015 #ifdef CONFIG_IP_ROUTE_FWMARK
2016         rth->fl.fl4_fwmark= skb->nfmark;
2017 #endif
2018         rth->fl.fl4_src = saddr;
2019         rth->rt_src     = saddr;
2020 #ifdef CONFIG_NET_CLS_ROUTE
2021         rth->u.dst.tclassid = itag;
2022 #endif
2023         rth->rt_iif     =
2024         rth->fl.iif     = dev->ifindex;
2025         rth->u.dst.dev  = &loopback_dev;
2026         dev_hold(rth->u.dst.dev);
2027         rth->idev       = in_dev_get(rth->u.dst.dev);
2028         rth->rt_gateway = daddr;
2029         rth->rt_spec_dst= spec_dst;
2030         rth->u.dst.input= ip_local_deliver;
2031         rth->rt_flags   = flags|RTCF_LOCAL;
2032         if (res.type == RTN_UNREACHABLE) {
2033                 rth->u.dst.input= ip_error;
2034                 rth->u.dst.error= -err;
2035                 rth->rt_flags   &= ~RTCF_LOCAL;
2036         }
2037         rth->rt_type    = res.type;
2038         hash = rt_hash_code(daddr, saddr ^ (fl.iif << 5));
2039         err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
2040         goto done;
2041
2042 no_route:
2043         RT_CACHE_STAT_INC(in_no_route);
2044         spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2045         res.type = RTN_UNREACHABLE;
2046         goto local_input;
2047
2048         /*
2049          *      Do not cache martian addresses: they should be logged (RFC1812)
2050          */
2051 martian_destination:
2052         RT_CACHE_STAT_INC(in_martian_dst);
2053 #ifdef CONFIG_IP_ROUTE_VERBOSE
2054         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
2055                 printk(KERN_WARNING "martian destination %u.%u.%u.%u from "
2056                         "%u.%u.%u.%u, dev %s\n",
2057                         NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
2058 #endif
2059
2060 e_hostunreach:
2061         err = -EHOSTUNREACH;
2062         goto done;
2063
2064 e_inval:
2065         err = -EINVAL;
2066         goto done;
2067
2068 e_nobufs:
2069         err = -ENOBUFS;
2070         goto done;
2071
2072 martian_source:
2073         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2074         goto e_inval;
2075 }
2076
2077 int ip_route_input(struct sk_buff *skb, u32 daddr, u32 saddr,
2078                    u8 tos, struct net_device *dev)
2079 {
2080         struct rtable * rth;
2081         unsigned        hash;
2082         int iif = dev->ifindex;
2083
2084         tos &= IPTOS_RT_MASK;
2085         hash = rt_hash_code(daddr, saddr ^ (iif << 5));
2086
2087         rcu_read_lock();
2088         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2089              rth = rcu_dereference(rth->u.rt_next)) {
2090                 if (rth->fl.fl4_dst == daddr &&
2091                     rth->fl.fl4_src == saddr &&
2092                     rth->fl.iif == iif &&
2093                     rth->fl.oif == 0 &&
2094 #ifdef CONFIG_IP_ROUTE_FWMARK
2095                     rth->fl.fl4_fwmark == skb->nfmark &&
2096 #endif
2097                     rth->fl.fl4_tos == tos) {
2098                         rth->u.dst.lastuse = jiffies;
2099                         dst_hold(&rth->u.dst);
2100                         rth->u.dst.__use++;
2101                         RT_CACHE_STAT_INC(in_hit);
2102                         rcu_read_unlock();
2103                         skb->dst = (struct dst_entry*)rth;
2104                         return 0;
2105                 }
2106                 RT_CACHE_STAT_INC(in_hlist_search);
2107         }
2108         rcu_read_unlock();
2109
2110         /* Multicast recognition logic is moved from route cache to here.
2111            The problem was that too many Ethernet cards have broken/missing
2112            hardware multicast filters :-( As result the host on multicasting
2113            network acquires a lot of useless route cache entries, sort of
2114            SDR messages from all the world. Now we try to get rid of them.
2115            Really, provided software IP multicast filter is organized
2116            reasonably (at least, hashed), it does not result in a slowdown
2117            comparing with route cache reject entries.
2118            Note, that multicast routers are not affected, because
2119            route cache entry is created eventually.
2120          */
2121         if (MULTICAST(daddr)) {
2122                 struct in_device *in_dev;
2123
2124                 rcu_read_lock();
2125                 if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
2126                         int our = ip_check_mc(in_dev, daddr, saddr,
2127                                 skb->nh.iph->protocol);
2128                         if (our
2129 #ifdef CONFIG_IP_MROUTE
2130                             || (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
2131 #endif
2132                             ) {
2133                                 rcu_read_unlock();
2134                                 return ip_route_input_mc(skb, daddr, saddr,
2135                                                          tos, dev, our);
2136                         }
2137                 }
2138                 rcu_read_unlock();
2139                 return -EINVAL;
2140         }
2141         return ip_route_input_slow(skb, daddr, saddr, tos, dev);
2142 }
2143
2144 static inline int __mkroute_output(struct rtable **result,
2145                                    struct fib_result* res,
2146                                    const struct flowi *fl,
2147                                    const struct flowi *oldflp,
2148                                    struct net_device *dev_out,
2149                                    unsigned flags)
2150 {
2151         struct rtable *rth;
2152         struct in_device *in_dev;
2153         u32 tos = RT_FL_TOS(oldflp);
2154         int err = 0;
2155
2156         if (LOOPBACK(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
2157                 return -EINVAL;
2158
2159         if (fl->fl4_dst == 0xFFFFFFFF)
2160                 res->type = RTN_BROADCAST;
2161         else if (MULTICAST(fl->fl4_dst))
2162                 res->type = RTN_MULTICAST;
2163         else if (BADCLASS(fl->fl4_dst) || ZERONET(fl->fl4_dst))
2164                 return -EINVAL;
2165
2166         if (dev_out->flags & IFF_LOOPBACK)
2167                 flags |= RTCF_LOCAL;
2168
2169         /* get work reference to inet device */
2170         in_dev = in_dev_get(dev_out);
2171         if (!in_dev)
2172                 return -EINVAL;
2173
2174         if (res->type == RTN_BROADCAST) {
2175                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2176                 if (res->fi) {
2177                         fib_info_put(res->fi);
2178                         res->fi = NULL;
2179                 }
2180         } else if (res->type == RTN_MULTICAST) {
2181                 flags |= RTCF_MULTICAST|RTCF_LOCAL;
2182                 if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
2183                                  oldflp->proto))
2184                         flags &= ~RTCF_LOCAL;
2185                 /* If multicast route do not exist use
2186                    default one, but do not gateway in this case.
2187                    Yes, it is hack.
2188                  */
2189                 if (res->fi && res->prefixlen < 4) {
2190                         fib_info_put(res->fi);
2191                         res->fi = NULL;
2192                 }
2193         }
2194
2195
2196         rth = dst_alloc(&ipv4_dst_ops);
2197         if (!rth) {
2198                 err = -ENOBUFS;
2199                 goto cleanup;
2200         }
2201
2202         atomic_set(&rth->u.dst.__refcnt, 1);
2203         rth->u.dst.flags= DST_HOST;
2204 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
2205         if (res->fi) {
2206                 rth->rt_multipath_alg = res->fi->fib_mp_alg;
2207                 if (res->fi->fib_nhs > 1)
2208                         rth->u.dst.flags |= DST_BALANCED;
2209         }
2210 #endif
2211         if (in_dev->cnf.no_xfrm)
2212                 rth->u.dst.flags |= DST_NOXFRM;
2213         if (in_dev->cnf.no_policy)
2214                 rth->u.dst.flags |= DST_NOPOLICY;
2215
2216         rth->fl.fl4_dst = oldflp->fl4_dst;
2217         rth->fl.fl4_tos = tos;
2218         rth->fl.fl4_src = oldflp->fl4_src;
2219         rth->fl.oif     = oldflp->oif;
2220 #ifdef CONFIG_IP_ROUTE_FWMARK
2221         rth->fl.fl4_fwmark= oldflp->fl4_fwmark;
2222 #endif
2223         rth->rt_dst     = fl->fl4_dst;
2224         rth->rt_src     = fl->fl4_src;
2225         rth->rt_iif     = oldflp->oif ? : dev_out->ifindex;
2226         /* get references to the devices that are to be hold by the routing
2227            cache entry */
2228         rth->u.dst.dev  = dev_out;
2229         dev_hold(dev_out);
2230         rth->idev       = in_dev_get(dev_out);
2231         rth->rt_gateway = fl->fl4_dst;
2232         rth->rt_spec_dst= fl->fl4_src;
2233
2234         rth->u.dst.output=ip_output;
2235
2236         RT_CACHE_STAT_INC(out_slow_tot);
2237
2238         if (flags & RTCF_LOCAL) {
2239                 rth->u.dst.input = ip_local_deliver;
2240                 rth->rt_spec_dst = fl->fl4_dst;
2241         }
2242         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2243                 rth->rt_spec_dst = fl->fl4_src;
2244                 if (flags & RTCF_LOCAL &&
2245                     !(dev_out->flags & IFF_LOOPBACK)) {
2246                         rth->u.dst.output = ip_mc_output;
2247                         RT_CACHE_STAT_INC(out_slow_mc);
2248                 }
2249 #ifdef CONFIG_IP_MROUTE
2250                 if (res->type == RTN_MULTICAST) {
2251                         if (IN_DEV_MFORWARD(in_dev) &&
2252                             !LOCAL_MCAST(oldflp->fl4_dst)) {
2253                                 rth->u.dst.input = ip_mr_input;
2254                                 rth->u.dst.output = ip_mc_output;
2255                         }
2256                 }
2257 #endif
2258         }
2259
2260         rt_set_nexthop(rth, res, 0);
2261
2262         rth->rt_flags = flags;
2263
2264         *result = rth;
2265  cleanup:
2266         /* release work reference to inet device */
2267         in_dev_put(in_dev);
2268
2269         return err;
2270 }
2271
2272 static inline int ip_mkroute_output_def(struct rtable **rp,
2273                                         struct fib_result* res,
2274                                         const struct flowi *fl,
2275                                         const struct flowi *oldflp,
2276                                         struct net_device *dev_out,
2277                                         unsigned flags)
2278 {
2279         struct rtable *rth = NULL;
2280         int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
2281         unsigned hash;
2282         if (err == 0) {
2283                 hash = rt_hash_code(oldflp->fl4_dst,
2284                                     oldflp->fl4_src ^ (oldflp->oif << 5));
2285                 err = rt_intern_hash(hash, rth, rp);
2286         }
2287
2288         return err;
2289 }
2290
2291 static inline int ip_mkroute_output(struct rtable** rp,
2292                                     struct fib_result* res,
2293                                     const struct flowi *fl,
2294                                     const struct flowi *oldflp,
2295                                     struct net_device *dev_out,
2296                                     unsigned flags)
2297 {
2298 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
2299         unsigned char hop;
2300         unsigned hash;
2301         int err = -EINVAL;
2302         struct rtable *rth = NULL;
2303
2304         if (res->fi && res->fi->fib_nhs > 1) {
2305                 unsigned char hopcount = res->fi->fib_nhs;
2306
2307                 for (hop = 0; hop < hopcount; hop++) {
2308                         struct net_device *dev2nexthop;
2309
2310                         res->nh_sel = hop;
2311
2312                         /* hold a work reference to the output device */
2313                         dev2nexthop = FIB_RES_DEV(*res);
2314                         dev_hold(dev2nexthop);
2315
2316                         /* put reference to previous result */
2317                         if (hop)
2318                                 ip_rt_put(*rp);
2319
2320                         err = __mkroute_output(&rth, res, fl, oldflp,
2321                                                dev2nexthop, flags);
2322
2323                         if (err != 0)
2324                                 goto cleanup;
2325
2326                         hash = rt_hash_code(oldflp->fl4_dst,
2327                                             oldflp->fl4_src ^
2328                                             (oldflp->oif << 5));
2329                         err = rt_intern_hash(hash, rth, rp);
2330
2331                         /* forward hop information to multipath impl. */
2332                         multipath_set_nhinfo(rth,
2333                                              FIB_RES_NETWORK(*res),
2334                                              FIB_RES_NETMASK(*res),
2335                                              res->prefixlen,
2336                                              &FIB_RES_NH(*res));
2337                 cleanup:
2338                         /* release work reference to output device */
2339                         dev_put(dev2nexthop);
2340
2341                         if (err != 0)
2342                                 return err;
2343                 }
2344                 return err;
2345         } else {
2346                 return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out,
2347                                              flags);
2348         }
2349 #else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
2350         return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out, flags);
2351 #endif
2352 }
2353
2354 /*
2355  * Major route resolver routine.
2356  */
2357
2358 static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
2359 {
2360         u32 tos = RT_FL_TOS(oldflp);
2361         struct flowi fl = { .nl_u = { .ip4_u =
2362                                       { .daddr = oldflp->fl4_dst,
2363                                         .saddr = oldflp->fl4_src,
2364                                         .tos = tos & IPTOS_RT_MASK,
2365                                         .scope = ((tos & RTO_ONLINK) ?
2366                                                   RT_SCOPE_LINK :
2367                                                   RT_SCOPE_UNIVERSE),
2368 #ifdef CONFIG_IP_ROUTE_FWMARK
2369                                         .fwmark = oldflp->fl4_fwmark
2370 #endif
2371                                       } },
2372                             .iif = loopback_dev.ifindex,
2373                             .oif = oldflp->oif };
2374         struct fib_result res;
2375         unsigned flags = 0;
2376         struct net_device *dev_out = NULL;
2377         int free_res = 0;
2378         int err;
2379
2380
2381         res.fi          = NULL;
2382 #ifdef CONFIG_IP_MULTIPLE_TABLES
2383         res.r           = NULL;
2384 #endif
2385
2386         if (oldflp->fl4_src) {
2387                 err = -EINVAL;
2388                 if (MULTICAST(oldflp->fl4_src) ||
2389                     BADCLASS(oldflp->fl4_src) ||
2390                     ZERONET(oldflp->fl4_src))
2391                         goto out;
2392
2393                 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2394                 dev_out = ip_dev_find(oldflp->fl4_src);
2395                 if (dev_out == NULL)
2396                         goto out;
2397
2398                 /* I removed check for oif == dev_out->oif here.
2399                    It was wrong for two reasons:
2400                    1. ip_dev_find(saddr) can return wrong iface, if saddr is
2401                       assigned to multiple interfaces.
2402                    2. Moreover, we are allowed to send packets with saddr
2403                       of another iface. --ANK
2404                  */
2405
2406                 if (oldflp->oif == 0
2407                     && (MULTICAST(oldflp->fl4_dst) || oldflp->fl4_dst == 0xFFFFFFFF)) {
2408                         /* Special hack: user can direct multicasts
2409                            and limited broadcast via necessary interface
2410                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2411                            This hack is not just for fun, it allows
2412                            vic,vat and friends to work.
2413                            They bind socket to loopback, set ttl to zero
2414                            and expect that it will work.
2415                            From the viewpoint of routing cache they are broken,
2416                            because we are not allowed to build multicast path
2417                            with loopback source addr (look, routing cache
2418                            cannot know, that ttl is zero, so that packet
2419                            will not leave this host and route is valid).
2420                            Luckily, this hack is good workaround.
2421                          */
2422
2423                         fl.oif = dev_out->ifindex;
2424                         goto make_route;
2425                 }
2426                 if (dev_out)
2427                         dev_put(dev_out);
2428                 dev_out = NULL;
2429         }
2430
2431
2432         if (oldflp->oif) {
2433                 dev_out = dev_get_by_index(oldflp->oif);
2434                 err = -ENODEV;
2435                 if (dev_out == NULL)
2436                         goto out;
2437
2438                 /* RACE: Check return value of inet_select_addr instead. */
2439                 if (__in_dev_get_rtnl(dev_out) == NULL) {
2440                         dev_put(dev_out);
2441                         goto out;       /* Wrong error code */
2442                 }
2443
2444                 if (LOCAL_MCAST(oldflp->fl4_dst) || oldflp->fl4_dst == 0xFFFFFFFF) {
2445                         if (!fl.fl4_src)
2446                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2447                                                               RT_SCOPE_LINK);
2448                         goto make_route;
2449                 }
2450                 if (!fl.fl4_src) {
2451                         if (MULTICAST(oldflp->fl4_dst))
2452                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2453                                                               fl.fl4_scope);
2454                         else if (!oldflp->fl4_dst)
2455                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2456                                                               RT_SCOPE_HOST);
2457                 }
2458         }
2459
2460         if (!fl.fl4_dst) {
2461                 fl.fl4_dst = fl.fl4_src;
2462                 if (!fl.fl4_dst)
2463                         fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
2464                 if (dev_out)
2465                         dev_put(dev_out);
2466                 dev_out = &loopback_dev;
2467                 dev_hold(dev_out);
2468                 fl.oif = loopback_dev.ifindex;
2469                 res.type = RTN_LOCAL;
2470                 flags |= RTCF_LOCAL;
2471                 goto make_route;
2472         }
2473
2474         if (fib_lookup(&fl, &res)) {
2475                 res.fi = NULL;
2476                 if (oldflp->oif) {
2477                         /* Apparently, routing tables are wrong. Assume,
2478                            that the destination is on link.
2479
2480                            WHY? DW.
2481                            Because we are allowed to send to iface
2482                            even if it has NO routes and NO assigned
2483                            addresses. When oif is specified, routing
2484                            tables are looked up with only one purpose:
2485                            to catch if destination is gatewayed, rather than
2486                            direct. Moreover, if MSG_DONTROUTE is set,
2487                            we send packet, ignoring both routing tables
2488                            and ifaddr state. --ANK
2489
2490
2491                            We could make it even if oif is unknown,
2492                            likely IPv6, but we do not.
2493                          */
2494
2495                         if (fl.fl4_src == 0)
2496                                 fl.fl4_src = inet_select_addr(dev_out, 0,
2497                                                               RT_SCOPE_LINK);
2498                         res.type = RTN_UNICAST;
2499                         goto make_route;
2500                 }
2501                 if (dev_out)
2502                         dev_put(dev_out);
2503                 err = -ENETUNREACH;
2504                 goto out;
2505         }
2506         free_res = 1;
2507
2508         if (res.type == RTN_LOCAL) {
2509                 if (!fl.fl4_src)
2510                         fl.fl4_src = fl.fl4_dst;
2511                 if (dev_out)
2512                         dev_put(dev_out);
2513                 dev_out = &loopback_dev;
2514                 dev_hold(dev_out);
2515                 fl.oif = dev_out->ifindex;
2516                 if (res.fi)
2517                         fib_info_put(res.fi);
2518                 res.fi = NULL;
2519                 flags |= RTCF_LOCAL;
2520                 goto make_route;
2521         }
2522
2523 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2524         if (res.fi->fib_nhs > 1 && fl.oif == 0)
2525                 fib_select_multipath(&fl, &res);
2526         else
2527 #endif
2528         if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif)
2529                 fib_select_default(&fl, &res);
2530
2531         if (!fl.fl4_src)
2532                 fl.fl4_src = FIB_RES_PREFSRC(res);
2533
2534         if (dev_out)
2535                 dev_put(dev_out);
2536         dev_out = FIB_RES_DEV(res);
2537         dev_hold(dev_out);
2538         fl.oif = dev_out->ifindex;
2539
2540
2541 make_route:
2542         err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
2543
2544
2545         if (free_res)
2546                 fib_res_put(&res);
2547         if (dev_out)
2548                 dev_put(dev_out);
2549 out:    return err;
2550 }
2551
2552 int __ip_route_output_key(struct rtable **rp, const struct flowi *flp)
2553 {
2554         unsigned hash;
2555         struct rtable *rth;
2556
2557         hash = rt_hash_code(flp->fl4_dst, flp->fl4_src ^ (flp->oif << 5));
2558
2559         rcu_read_lock_bh();
2560         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2561                 rth = rcu_dereference(rth->u.rt_next)) {
2562                 if (rth->fl.fl4_dst == flp->fl4_dst &&
2563                     rth->fl.fl4_src == flp->fl4_src &&
2564                     rth->fl.iif == 0 &&
2565                     rth->fl.oif == flp->oif &&
2566 #ifdef CONFIG_IP_ROUTE_FWMARK
2567                     rth->fl.fl4_fwmark == flp->fl4_fwmark &&
2568 #endif
2569                     !((rth->fl.fl4_tos ^ flp->fl4_tos) &
2570                             (IPTOS_RT_MASK | RTO_ONLINK))) {
2571
2572                         /* check for multipath routes and choose one if
2573                          * necessary
2574                          */
2575                         if (multipath_select_route(flp, rth, rp)) {
2576                                 dst_hold(&(*rp)->u.dst);
2577                                 RT_CACHE_STAT_INC(out_hit);
2578                                 rcu_read_unlock_bh();
2579                                 return 0;
2580                         }
2581
2582                         rth->u.dst.lastuse = jiffies;
2583                         dst_hold(&rth->u.dst);
2584                         rth->u.dst.__use++;
2585                         RT_CACHE_STAT_INC(out_hit);
2586                         rcu_read_unlock_bh();
2587                         *rp = rth;
2588                         return 0;
2589                 }
2590                 RT_CACHE_STAT_INC(out_hlist_search);
2591         }
2592         rcu_read_unlock_bh();
2593
2594         return ip_route_output_slow(rp, flp);
2595 }
2596
2597 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2598
2599 int ip_route_output_flow(struct rtable **rp, struct flowi *flp, struct sock *sk, int flags)
2600 {
2601         int err;
2602
2603         if ((err = __ip_route_output_key(rp, flp)) != 0)
2604                 return err;
2605
2606         if (flp->proto) {
2607                 if (!flp->fl4_src)
2608                         flp->fl4_src = (*rp)->rt_src;
2609                 if (!flp->fl4_dst)
2610                         flp->fl4_dst = (*rp)->rt_dst;
2611                 return xfrm_lookup((struct dst_entry **)rp, flp, sk, flags);
2612         }
2613
2614         return 0;
2615 }
2616
2617 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2618
2619 int ip_route_output_key(struct rtable **rp, struct flowi *flp)
2620 {
2621         return ip_route_output_flow(rp, flp, NULL, 0);
2622 }
2623
2624 static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2625                         int nowait, unsigned int flags)
2626 {
2627         struct rtable *rt = (struct rtable*)skb->dst;
2628         struct rtmsg *r;
2629         struct nlmsghdr  *nlh;
2630         unsigned char    *b = skb->tail;
2631         struct rta_cacheinfo ci;
2632 #ifdef CONFIG_IP_MROUTE
2633         struct rtattr *eptr;
2634 #endif
2635         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
2636         r = NLMSG_DATA(nlh);
2637         r->rtm_family    = AF_INET;
2638         r->rtm_dst_len  = 32;
2639         r->rtm_src_len  = 0;
2640         r->rtm_tos      = rt->fl.fl4_tos;
2641         r->rtm_table    = RT_TABLE_MAIN;
2642         r->rtm_type     = rt->rt_type;
2643         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2644         r->rtm_protocol = RTPROT_UNSPEC;
2645         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2646         if (rt->rt_flags & RTCF_NOTIFY)
2647                 r->rtm_flags |= RTM_F_NOTIFY;
2648         RTA_PUT(skb, RTA_DST, 4, &rt->rt_dst);
2649         if (rt->fl.fl4_src) {
2650                 r->rtm_src_len = 32;
2651                 RTA_PUT(skb, RTA_SRC, 4, &rt->fl.fl4_src);
2652         }
2653         if (rt->u.dst.dev)
2654                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
2655 #ifdef CONFIG_NET_CLS_ROUTE
2656         if (rt->u.dst.tclassid)
2657                 RTA_PUT(skb, RTA_FLOW, 4, &rt->u.dst.tclassid);
2658 #endif
2659 #ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
2660         if (rt->rt_multipath_alg != IP_MP_ALG_NONE) {
2661                 __u32 alg = rt->rt_multipath_alg;
2662
2663                 RTA_PUT(skb, RTA_MP_ALGO, 4, &alg);
2664         }
2665 #endif
2666         if (rt->fl.iif)
2667                 RTA_PUT(skb, RTA_PREFSRC, 4, &rt->rt_spec_dst);
2668         else if (rt->rt_src != rt->fl.fl4_src)
2669                 RTA_PUT(skb, RTA_PREFSRC, 4, &rt->rt_src);
2670         if (rt->rt_dst != rt->rt_gateway)
2671                 RTA_PUT(skb, RTA_GATEWAY, 4, &rt->rt_gateway);
2672         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2673                 goto rtattr_failure;
2674         ci.rta_lastuse  = jiffies_to_clock_t(jiffies - rt->u.dst.lastuse);
2675         ci.rta_used     = rt->u.dst.__use;
2676         ci.rta_clntref  = atomic_read(&rt->u.dst.__refcnt);
2677         if (rt->u.dst.expires)
2678                 ci.rta_expires = jiffies_to_clock_t(rt->u.dst.expires - jiffies);
2679         else
2680                 ci.rta_expires = 0;
2681         ci.rta_error    = rt->u.dst.error;
2682         ci.rta_id       = ci.rta_ts = ci.rta_tsage = 0;
2683         if (rt->peer) {
2684                 ci.rta_id = rt->peer->ip_id_count;
2685                 if (rt->peer->tcp_ts_stamp) {
2686                         ci.rta_ts = rt->peer->tcp_ts;
2687                         ci.rta_tsage = xtime.tv_sec - rt->peer->tcp_ts_stamp;
2688                 }
2689         }
2690 #ifdef CONFIG_IP_MROUTE
2691         eptr = (struct rtattr*)skb->tail;
2692 #endif
2693         RTA_PUT(skb, RTA_CACHEINFO, sizeof(ci), &ci);
2694         if (rt->fl.iif) {
2695 #ifdef CONFIG_IP_MROUTE
2696                 u32 dst = rt->rt_dst;
2697
2698                 if (MULTICAST(dst) && !LOCAL_MCAST(dst) &&
2699                     ipv4_devconf.mc_forwarding) {
2700                         int err = ipmr_get_route(skb, r, nowait);
2701                         if (err <= 0) {
2702                                 if (!nowait) {
2703                                         if (err == 0)
2704                                                 return 0;
2705                                         goto nlmsg_failure;
2706                                 } else {
2707                                         if (err == -EMSGSIZE)
2708                                                 goto nlmsg_failure;
2709                                         ((struct rta_cacheinfo*)RTA_DATA(eptr))->rta_error = err;
2710                                 }
2711                         }
2712                 } else
2713 #endif
2714                         RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
2715         }
2716
2717         nlh->nlmsg_len = skb->tail - b;
2718         return skb->len;
2719
2720 nlmsg_failure:
2721 rtattr_failure:
2722         skb_trim(skb, b - skb->data);
2723         return -1;
2724 }
2725
2726 int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
2727 {
2728         struct rtattr **rta = arg;
2729         struct rtmsg *rtm = NLMSG_DATA(nlh);
2730         struct rtable *rt = NULL;
2731         u32 dst = 0;
2732         u32 src = 0;
2733         int iif = 0;
2734         int err = -ENOBUFS;
2735         struct sk_buff *skb;
2736
2737         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2738         if (!skb)
2739                 goto out;
2740
2741         /* Reserve room for dummy headers, this skb can pass
2742            through good chunk of routing engine.
2743          */
2744         skb->mac.raw = skb->nh.raw = skb->data;
2745
2746         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2747         skb->nh.iph->protocol = IPPROTO_ICMP;
2748         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2749
2750         if (rta[RTA_SRC - 1])
2751                 memcpy(&src, RTA_DATA(rta[RTA_SRC - 1]), 4);
2752         if (rta[RTA_DST - 1])
2753                 memcpy(&dst, RTA_DATA(rta[RTA_DST - 1]), 4);
2754         if (rta[RTA_IIF - 1])
2755                 memcpy(&iif, RTA_DATA(rta[RTA_IIF - 1]), sizeof(int));
2756
2757         if (iif) {
2758                 struct net_device *dev = __dev_get_by_index(iif);
2759                 err = -ENODEV;
2760                 if (!dev)
2761                         goto out_free;
2762                 skb->protocol   = htons(ETH_P_IP);
2763                 skb->dev        = dev;
2764                 local_bh_disable();
2765                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2766                 local_bh_enable();
2767                 rt = (struct rtable*)skb->dst;
2768                 if (!err && rt->u.dst.error)
2769                         err = -rt->u.dst.error;
2770         } else {
2771                 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = dst,
2772                                                          .saddr = src,
2773                                                          .tos = rtm->rtm_tos } } };
2774                 int oif = 0;
2775                 if (rta[RTA_OIF - 1])
2776                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
2777                 fl.oif = oif;
2778                 err = ip_route_output_key(&rt, &fl);
2779         }
2780         if (err)
2781                 goto out_free;
2782
2783         skb->dst = &rt->u.dst;
2784         if (rtm->rtm_flags & RTM_F_NOTIFY)
2785                 rt->rt_flags |= RTCF_NOTIFY;
2786
2787         NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
2788
2789         err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2790                                 RTM_NEWROUTE, 0, 0);
2791         if (!err)
2792                 goto out_free;
2793         if (err < 0) {
2794                 err = -EMSGSIZE;
2795                 goto out_free;
2796         }
2797
2798         err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
2799         if (err > 0)
2800                 err = 0;
2801 out:    return err;
2802
2803 out_free:
2804         kfree_skb(skb);
2805         goto out;
2806 }
2807
2808 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
2809 {
2810         struct rtable *rt;
2811         int h, s_h;
2812         int idx, s_idx;
2813
2814         s_h = cb->args[0];
2815         s_idx = idx = cb->args[1];
2816         for (h = 0; h <= rt_hash_mask; h++) {
2817                 if (h < s_h) continue;
2818                 if (h > s_h)
2819                         s_idx = 0;
2820                 rcu_read_lock_bh();
2821                 for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2822                      rt = rcu_dereference(rt->u.rt_next), idx++) {
2823                         if (idx < s_idx)
2824                                 continue;
2825                         skb->dst = dst_clone(&rt->u.dst);
2826                         if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
2827                                          cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2828                                          1, NLM_F_MULTI) <= 0) {
2829                                 dst_release(xchg(&skb->dst, NULL));
2830                                 rcu_read_unlock_bh();
2831                                 goto done;
2832                         }
2833                         dst_release(xchg(&skb->dst, NULL));
2834                 }
2835                 rcu_read_unlock_bh();
2836         }
2837
2838 done:
2839         cb->args[0] = h;
2840         cb->args[1] = idx;
2841         return skb->len;
2842 }
2843
2844 void ip_rt_multicast_event(struct in_device *in_dev)
2845 {
2846         rt_cache_flush(0);
2847 }
2848
2849 #ifdef CONFIG_SYSCTL
2850 static int flush_delay;
2851
2852 static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,
2853                                         struct file *filp, void __user *buffer,
2854                                         size_t *lenp, loff_t *ppos)
2855 {
2856         if (write) {
2857                 proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
2858                 rt_cache_flush(flush_delay);
2859                 return 0;
2860         }
2861
2862         return -EINVAL;
2863 }
2864
2865 static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table,
2866                                                 int __user *name,
2867                                                 int nlen,
2868                                                 void __user *oldval,
2869                                                 size_t __user *oldlenp,
2870                                                 void __user *newval,
2871                                                 size_t newlen,
2872                                                 void **context)
2873 {
2874         int delay;
2875         if (newlen != sizeof(int))
2876                 return -EINVAL;
2877         if (get_user(delay, (int __user *)newval))
2878                 return -EFAULT;
2879         rt_cache_flush(delay);
2880         return 0;
2881 }
2882
2883 ctl_table ipv4_route_table[] = {
2884         {
2885                 .ctl_name       = NET_IPV4_ROUTE_FLUSH,
2886                 .procname       = "flush",
2887                 .data           = &flush_delay,
2888                 .maxlen         = sizeof(int),
2889                 .mode           = 0200,
2890                 .proc_handler   = &ipv4_sysctl_rtcache_flush,
2891                 .strategy       = &ipv4_sysctl_rtcache_flush_strategy,
2892         },
2893         {
2894                 .ctl_name       = NET_IPV4_ROUTE_MIN_DELAY,
2895                 .procname       = "min_delay",
2896                 .data           = &ip_rt_min_delay,
2897                 .maxlen         = sizeof(int),
2898                 .mode           = 0644,
2899                 .proc_handler   = &proc_dointvec_jiffies,
2900                 .strategy       = &sysctl_jiffies,
2901         },
2902         {
2903                 .ctl_name       = NET_IPV4_ROUTE_MAX_DELAY,
2904                 .procname       = "max_delay",
2905                 .data           = &ip_rt_max_delay,
2906                 .maxlen         = sizeof(int),
2907                 .mode           = 0644,
2908                 .proc_handler   = &proc_dointvec_jiffies,
2909                 .strategy       = &sysctl_jiffies,
2910         },
2911         {
2912                 .ctl_name       = NET_IPV4_ROUTE_GC_THRESH,
2913                 .procname       = "gc_thresh",
2914                 .data           = &ipv4_dst_ops.gc_thresh,
2915                 .maxlen         = sizeof(int),
2916                 .mode           = 0644,
2917                 .proc_handler   = &proc_dointvec,
2918         },
2919         {
2920                 .ctl_name       = NET_IPV4_ROUTE_MAX_SIZE,
2921                 .procname       = "max_size",
2922                 .data           = &ip_rt_max_size,
2923                 .maxlen         = sizeof(int),
2924                 .mode           = 0644,
2925                 .proc_handler   = &proc_dointvec,
2926         },
2927         {
2928                 /*  Deprecated. Use gc_min_interval_ms */
2929
2930                 .ctl_name       = NET_IPV4_ROUTE_GC_MIN_INTERVAL,
2931                 .procname       = "gc_min_interval",
2932                 .data           = &ip_rt_gc_min_interval,
2933                 .maxlen         = sizeof(int),
2934                 .mode           = 0644,
2935                 .proc_handler   = &proc_dointvec_jiffies,
2936                 .strategy       = &sysctl_jiffies,
2937         },
2938         {
2939                 .ctl_name       = NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS,
2940                 .procname       = "gc_min_interval_ms",
2941                 .data           = &ip_rt_gc_min_interval,
2942                 .maxlen         = sizeof(int),
2943                 .mode           = 0644,
2944                 .proc_handler   = &proc_dointvec_ms_jiffies,
2945                 .strategy       = &sysctl_ms_jiffies,
2946         },
2947         {
2948                 .ctl_name       = NET_IPV4_ROUTE_GC_TIMEOUT,
2949                 .procname       = "gc_timeout",
2950                 .data           = &ip_rt_gc_timeout,
2951                 .maxlen         = sizeof(int),
2952                 .mode           = 0644,
2953                 .proc_handler   = &proc_dointvec_jiffies,
2954                 .strategy       = &sysctl_jiffies,
2955         },
2956         {
2957                 .ctl_name       = NET_IPV4_ROUTE_GC_INTERVAL,
2958                 .procname       = "gc_interval",
2959                 .data           = &ip_rt_gc_interval,
2960                 .maxlen         = sizeof(int),
2961                 .mode           = 0644,
2962                 .proc_handler   = &proc_dointvec_jiffies,
2963                 .strategy       = &sysctl_jiffies,
2964         },
2965         {
2966                 .ctl_name       = NET_IPV4_ROUTE_REDIRECT_LOAD,
2967                 .procname       = "redirect_load",
2968                 .data           = &ip_rt_redirect_load,
2969                 .maxlen         = sizeof(int),
2970                 .mode           = 0644,
2971                 .proc_handler   = &proc_dointvec,
2972         },
2973         {
2974                 .ctl_name       = NET_IPV4_ROUTE_REDIRECT_NUMBER,
2975                 .procname       = "redirect_number",
2976                 .data           = &ip_rt_redirect_number,
2977                 .maxlen         = sizeof(int),
2978                 .mode           = 0644,
2979                 .proc_handler   = &proc_dointvec,
2980         },
2981         {
2982                 .ctl_name       = NET_IPV4_ROUTE_REDIRECT_SILENCE,
2983                 .procname       = "redirect_silence",
2984                 .data           = &ip_rt_redirect_silence,
2985                 .maxlen         = sizeof(int),
2986                 .mode           = 0644,
2987                 .proc_handler   = &proc_dointvec,
2988         },
2989         {
2990                 .ctl_name       = NET_IPV4_ROUTE_ERROR_COST,
2991                 .procname       = "error_cost",
2992                 .data           = &ip_rt_error_cost,
2993                 .maxlen         = sizeof(int),
2994                 .mode           = 0644,
2995                 .proc_handler   = &proc_dointvec,
2996         },
2997         {
2998                 .ctl_name       = NET_IPV4_ROUTE_ERROR_BURST,
2999                 .procname       = "error_burst",
3000                 .data           = &ip_rt_error_burst,
3001                 .maxlen         = sizeof(int),
3002                 .mode           = 0644,
3003                 .proc_handler   = &proc_dointvec,
3004         },
3005         {
3006                 .ctl_name       = NET_IPV4_ROUTE_GC_ELASTICITY,
3007                 .procname       = "gc_elasticity",
3008                 .data           = &ip_rt_gc_elasticity,
3009                 .maxlen         = sizeof(int),
3010                 .mode           = 0644,
3011                 .proc_handler   = &proc_dointvec,
3012         },
3013         {
3014                 .ctl_name       = NET_IPV4_ROUTE_MTU_EXPIRES,
3015                 .procname       = "mtu_expires",
3016                 .data           = &ip_rt_mtu_expires,
3017                 .maxlen         = sizeof(int),
3018                 .mode           = 0644,
3019                 .proc_handler   = &proc_dointvec_jiffies,
3020                 .strategy       = &sysctl_jiffies,
3021         },
3022         {
3023                 .ctl_name       = NET_IPV4_ROUTE_MIN_PMTU,
3024                 .procname       = "min_pmtu",
3025                 .data           = &ip_rt_min_pmtu,
3026                 .maxlen         = sizeof(int),
3027                 .mode           = 0644,
3028                 .proc_handler   = &proc_dointvec,
3029         },
3030         {
3031                 .ctl_name       = NET_IPV4_ROUTE_MIN_ADVMSS,
3032                 .procname       = "min_adv_mss",
3033                 .data           = &ip_rt_min_advmss,
3034                 .maxlen         = sizeof(int),
3035                 .mode           = 0644,
3036                 .proc_handler   = &proc_dointvec,
3037         },
3038         {
3039                 .ctl_name       = NET_IPV4_ROUTE_SECRET_INTERVAL,
3040                 .procname       = "secret_interval",
3041                 .data           = &ip_rt_secret_interval,
3042                 .maxlen         = sizeof(int),
3043                 .mode           = 0644,
3044                 .proc_handler   = &proc_dointvec_jiffies,
3045                 .strategy       = &sysctl_jiffies,
3046         },
3047         { .ctl_name = 0 }
3048 };
3049 #endif
3050
3051 #ifdef CONFIG_NET_CLS_ROUTE
3052 struct ip_rt_acct *ip_rt_acct;
3053
3054 /* This code sucks.  But you should have seen it before! --RR */
3055
3056 /* IP route accounting ptr for this logical cpu number. */
3057 #define IP_RT_ACCT_CPU(i) (ip_rt_acct + i * 256)
3058
3059 #ifdef CONFIG_PROC_FS
3060 static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
3061                            int length, int *eof, void *data)
3062 {
3063         unsigned int i;
3064
3065         if ((offset & 3) || (length & 3))
3066                 return -EIO;
3067
3068         if (offset >= sizeof(struct ip_rt_acct) * 256) {
3069                 *eof = 1;
3070                 return 0;
3071         }
3072
3073         if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
3074                 length = sizeof(struct ip_rt_acct) * 256 - offset;
3075                 *eof = 1;
3076         }
3077
3078         offset /= sizeof(u32);
3079
3080         if (length > 0) {
3081                 u32 *src = ((u32 *) IP_RT_ACCT_CPU(0)) + offset;
3082                 u32 *dst = (u32 *) buffer;
3083
3084                 /* Copy first cpu. */
3085                 *start = buffer;
3086                 memcpy(dst, src, length);
3087
3088                 /* Add the other cpus in, one int at a time */
3089                 for_each_possible_cpu(i) {
3090                         unsigned int j;
3091
3092                         src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset;
3093
3094                         for (j = 0; j < length/4; j++)
3095                                 dst[j] += src[j];
3096                 }
3097         }
3098         return length;
3099 }
3100 #endif /* CONFIG_PROC_FS */
3101 #endif /* CONFIG_NET_CLS_ROUTE */
3102
3103 static __initdata unsigned long rhash_entries;
3104 static int __init set_rhash_entries(char *str)
3105 {
3106         if (!str)
3107                 return 0;
3108         rhash_entries = simple_strtoul(str, &str, 0);
3109         return 1;
3110 }
3111 __setup("rhash_entries=", set_rhash_entries);
3112
3113 int __init ip_rt_init(void)
3114 {
3115         int rc = 0;
3116
3117         rt_hash_rnd = (int) ((num_physpages ^ (num_physpages>>8)) ^
3118                              (jiffies ^ (jiffies >> 7)));
3119
3120 #ifdef CONFIG_NET_CLS_ROUTE
3121         {
3122         int order;
3123         for (order = 0;
3124              (PAGE_SIZE << order) < 256 * sizeof(struct ip_rt_acct) * NR_CPUS; order++)
3125                 /* NOTHING */;
3126         ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order);
3127         if (!ip_rt_acct)
3128                 panic("IP: failed to allocate ip_rt_acct\n");
3129         memset(ip_rt_acct, 0, PAGE_SIZE << order);
3130         }
3131 #endif
3132
3133         ipv4_dst_ops.kmem_cachep = kmem_cache_create("ip_dst_cache",
3134                                                      sizeof(struct rtable),
3135                                                      0, SLAB_HWCACHE_ALIGN,
3136                                                      NULL, NULL);
3137
3138         if (!ipv4_dst_ops.kmem_cachep)
3139                 panic("IP: failed to allocate ip_dst_cache\n");
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                                         HASH_HIGHMEM,
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);