net/ipv4/route.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              ROUTE - implementation of the IP router.
   7  *
   8  * Authors:     Ross Biro
   9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  11  *              Linus Torvalds, <Linus.Torvalds@helsinki.fi>
  12  *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  13  *
  14  * Fixes:
  15  *              Alan Cox        :       Verify area fixes.
  16  *              Alan Cox        :       cli() protects routing changes
  17  *              Rui Oliveira    :       ICMP routing table updates
  18  *              (rco@di.uminho.pt)      Routing table insertion and update
  19  *              Linus Torvalds  :       Rewrote bits to be sensible
  20  *              Alan Cox        :       Added BSD route gw semantics
  21  *              Alan Cox        :       Super /proc >4K
  22  *              Alan Cox        :       MTU in route table
  23  *              Alan Cox        :       MSS actually. Also added the window
  24  *                                      clamper.
  25  *              Sam Lantinga    :       Fixed route matching in rt_del()
  26  *              Alan Cox        :       Routing cache support.
  27  *              Alan Cox        :       Removed compatibility cruft.
  28  *              Alan Cox        :       RTF_REJECT support.
  29  *              Alan Cox        :       TCP irtt support.
  30  *              Jonathan Naylor :       Added Metric support.
  31  *      Miquel van Smoorenburg  :       BSD API fixes.
  32  *      Miquel van Smoorenburg  :       Metrics.
  33  *              Alan Cox        :       Use __u32 properly
  34  *              Alan Cox        :       Aligned routing errors more closely with BSD
  35  *                                      our system is still very different.
  36  *              Alan Cox        :       Faster /proc handling
  37  *      Alexey Kuznetsov        :       Massive rework to support tree based routing,
  38  *                                      routing caches and better behaviour.
  39  *
  40  *              Olaf Erb        :       irtt wasn't being copied right.
  41  *              Bjorn Ekwall    :       Kerneld route support.
  42  *              Alan Cox        :       Multicast fixed (I hope)
  43  *              Pavel Krauz     :       Limited broadcast fixed
  44  *              Mike McLagan    :       Routing by source
  45  *      Alexey Kuznetsov        :       End of old history. Split to fib.c and
  46  *                                      route.c and rewritten from scratch.
  47  *              Andi Kleen      :       Load-limit warning messages.
  48  *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
  49  *      Vitaly E. Lavrov        :       Race condition in ip_route_input_slow.
  50  *      Tobias Ringstrom        :       Uninitialized res.type in ip_route_output_slow.
  51  *      Vladimir V. Ivanov      :       IP rule info (flowid) is really useful.
  52  *              Marc Boucher    :       routing by fwmark
  53  *      Robert Olsson           :       Added rt_cache statistics
  54  *      Arnaldo C. Melo         :       Convert proc stuff to seq_file
  55  *      Eric Dumazet            :       hashed spinlocks and rt_check_expire() fixes.
  56  *      Ilia Sotnikov           :       Ignore TOS on PMTUD and Redirect
  57  *      Ilia Sotnikov           :       Removed TOS from hash calculations
  58  *
  59  *              This program is free software; you can redistribute it and/or
  60  *              modify it under the terms of the GNU General Public License
  61  *              as published by the Free Software Foundation; either version
  62  *              2 of the License, or (at your option) any later version.
  63  */
  64
  65 #include <linux/module.h>
  66 #include <asm/uaccess.h>
  67 #include <asm/system.h>
  68 #include <linux/bitops.h>
  69 #include <linux/types.h>
  70 #include <linux/kernel.h>
  71 #include <linux/mm.h>
  72 #include <linux/bootmem.h>
  73 #include <linux/string.h>
  74 #include <linux/socket.h>
  75 #include <linux/sockios.h>
  76 #include <linux/errno.h>
  77 #include <linux/in.h>
  78 #include <linux/inet.h>
  79 #include <linux/netdevice.h>
  80 #include <linux/proc_fs.h>
  81 #include <linux/init.h>
  82 #include <linux/workqueue.h>
  83 #include <linux/skbuff.h>
  84 #include <linux/inetdevice.h>
  85 #include <linux/igmp.h>
  86 #include <linux/pkt_sched.h>
  87 #include <linux/mroute.h>
  88 #include <linux/netfilter_ipv4.h>
  89 #include <linux/random.h>
  90 #include <linux/jhash.h>
  91 #include <linux/rcupdate.h>
  92 #include <linux/times.h>
  93 #include <linux/slab.h>
  94 #include <net/dst.h>
  95 #include <net/net_namespace.h>
  96 #include <net/protocol.h>
  97 #include <net/ip.h>
  98 #include <net/route.h>
  99 #include <net/inetpeer.h>
 100 #include <net/sock.h>
 101 #include <net/ip_fib.h>
 102 #include <net/arp.h>
 103 #include <net/tcp.h>
 104 #include <net/icmp.h>
 105 #include <net/xfrm.h>
 106 #include <net/netevent.h>
 107 #include <net/rtnetlink.h>
 108 #ifdef CONFIG_SYSCTL
 109 #include <linux/sysctl.h>
 110 #endif
 111
 112 #define RT_FL_TOS(oldflp4) \
 113     ((u32)(oldflp4->flowi4_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_max_size;
 120 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 121 static int ip_rt_gc_interval __read_mostly      = 60 * HZ;
 122 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
 123 static int ip_rt_redirect_number __read_mostly  = 9;
 124 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 126 static int ip_rt_error_cost __read_mostly       = HZ;
 127 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 128 static int ip_rt_gc_elasticity __read_mostly    = 8;
 129 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
 130 static int ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
 131 static int ip_rt_min_advmss __read_mostly       = 256;
 132 static int rt_chain_length_max __read_mostly    = 20;
 133
 134 /*
 135  *      Interface to generic destination cache.
 136  */
 137
 138 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 139 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 140 static unsigned int      ipv4_default_mtu(const struct dst_entry *dst);
 141 static void              ipv4_dst_destroy(struct dst_entry *dst);
 142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
 143 static void              ipv4_link_failure(struct sk_buff *skb);
 144 static void              ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
 145 static int rt_garbage_collect(struct dst_ops *ops);
 146
 147 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 148                             int how)
 149 {
 150 }
 151
 152 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 153 {
 154         struct rtable *rt = (struct rtable *) dst;
 155         struct inet_peer *peer;
 156         u32 *p = NULL;
 157
 158         if (!rt->peer)
 159                 rt_bind_peer(rt, 1);
 160
 161         peer = rt->peer;
 162         if (peer) {
 163                 u32 *old_p = __DST_METRICS_PTR(old);
 164                 unsigned long prev, new;
 165
 166                 p = peer->metrics;
 167                 if (inet_metrics_new(peer))
 168                         memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
 169
 170                 new = (unsigned long) p;
 171                 prev = cmpxchg(&dst->_metrics, old, new);
 172
 173                 if (prev != old) {
 174                         p = __DST_METRICS_PTR(prev);
 175                         if (prev & DST_METRICS_READ_ONLY)
 176                                 p = NULL;
 177                 } else {
 178                         if (rt->fi) {
 179                                 fib_info_put(rt->fi);
 180                                 rt->fi = NULL;
 181                         }
 182                 }
 183         }
 184         return p;
 185 }
 186
 187 static struct dst_ops ipv4_dst_ops = {
 188         .family =               AF_INET,
 189         .protocol =             cpu_to_be16(ETH_P_IP),
 190         .gc =                   rt_garbage_collect,
 191         .check =                ipv4_dst_check,
 192         .default_advmss =       ipv4_default_advmss,
 193         .default_mtu =          ipv4_default_mtu,
 194         .cow_metrics =          ipv4_cow_metrics,
 195         .destroy =              ipv4_dst_destroy,
 196         .ifdown =               ipv4_dst_ifdown,
 197         .negative_advice =      ipv4_negative_advice,
 198         .link_failure =         ipv4_link_failure,
 199         .update_pmtu =          ip_rt_update_pmtu,
 200         .local_out =            __ip_local_out,
 201 };
 202
 203 #define ECN_OR_COST(class)      TC_PRIO_##class
 204
 205 const __u8 ip_tos2prio[16] = {
 206         TC_PRIO_BESTEFFORT,
 207         ECN_OR_COST(BESTEFFORT),
 208         TC_PRIO_BESTEFFORT,
 209         ECN_OR_COST(BESTEFFORT),
 210         TC_PRIO_BULK,
 211         ECN_OR_COST(BULK),
 212         TC_PRIO_BULK,
 213         ECN_OR_COST(BULK),
 214         TC_PRIO_INTERACTIVE,
 215         ECN_OR_COST(INTERACTIVE),
 216         TC_PRIO_INTERACTIVE,
 217         ECN_OR_COST(INTERACTIVE),
 218         TC_PRIO_INTERACTIVE_BULK,
 219         ECN_OR_COST(INTERACTIVE_BULK),
 220         TC_PRIO_INTERACTIVE_BULK,
 221         ECN_OR_COST(INTERACTIVE_BULK)
 222 };
 223
 224
 225 /*
 226  * Route cache.
 227  */
 228
 229 /* The locking scheme is rather straight forward:
 230  *
 231  * 1) Read-Copy Update protects the buckets of the central route hash.
 232  * 2) Only writers remove entries, and they hold the lock
 233  *    as they look at rtable reference counts.
 234  * 3) Only readers acquire references to rtable entries,
 235  *    they do so with atomic increments and with the
 236  *    lock held.
 237  */
 238
 239 struct rt_hash_bucket {
 240         struct rtable __rcu     *chain;
 241 };
 242
 243 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
 244         defined(CONFIG_PROVE_LOCKING)
 245 /*
 246  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
 247  * The size of this table is a power of two and depends on the number of CPUS.
 248  * (on lockdep we have a quite big spinlock_t, so keep the size down there)
 249  */
 250 #ifdef CONFIG_LOCKDEP
 251 # define RT_HASH_LOCK_SZ        256
 252 #else
 253 # if NR_CPUS >= 32
 254 #  define RT_HASH_LOCK_SZ       4096
 255 # elif NR_CPUS >= 16
 256 #  define RT_HASH_LOCK_SZ       2048
 257 # elif NR_CPUS >= 8
 258 #  define RT_HASH_LOCK_SZ       1024
 259 # elif NR_CPUS >= 4
 260 #  define RT_HASH_LOCK_SZ       512
 261 # else
 262 #  define RT_HASH_LOCK_SZ       256
 263 # endif
 264 #endif
 265
 266 static spinlock_t       *rt_hash_locks;
 267 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
 268
 269 static __init void rt_hash_lock_init(void)
 270 {
 271         int i;
 272
 273         rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
 274                         GFP_KERNEL);
 275         if (!rt_hash_locks)
 276                 panic("IP: failed to allocate rt_hash_locks\n");
 277
 278         for (i = 0; i < RT_HASH_LOCK_SZ; i++)
 279                 spin_lock_init(&rt_hash_locks[i]);
 280 }
 281 #else
 282 # define rt_hash_lock_addr(slot) NULL
 283
 284 static inline void rt_hash_lock_init(void)
 285 {
 286 }
 287 #endif
 288
 289 static struct rt_hash_bucket    *rt_hash_table __read_mostly;
 290 static unsigned                 rt_hash_mask __read_mostly;
 291 static unsigned int             rt_hash_log  __read_mostly;
 292
 293 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 294 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
 295
 296 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
 297                                    int genid)
 298 {
 299         return jhash_3words((__force u32)daddr, (__force u32)saddr,
 300                             idx, genid)
 301                 & rt_hash_mask;
 302 }
 303
 304 static inline int rt_genid(struct net *net)
 305 {
 306         return atomic_read(&net->ipv4.rt_genid);
 307 }
 308
 309 #ifdef CONFIG_PROC_FS
 310 struct rt_cache_iter_state {
 311         struct seq_net_private p;
 312         int bucket;
 313         int genid;
 314 };
 315
 316 static struct rtable *rt_cache_get_first(struct seq_file *seq)
 317 {
 318         struct rt_cache_iter_state *st = seq->private;
 319         struct rtable *r = NULL;
 320
 321         for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
 322                 if (!rcu_dereference_raw(rt_hash_table[st->bucket].chain))
 323                         continue;
 324                 rcu_read_lock_bh();
 325                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 326                 while (r) {
 327                         if (dev_net(r->dst.dev) == seq_file_net(seq) &&
 328                             r->rt_genid == st->genid)
 329                                 return r;
 330                         r = rcu_dereference_bh(r->dst.rt_next);
 331                 }
 332                 rcu_read_unlock_bh();
 333         }
 334         return r;
 335 }
 336
 337 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
 338                                           struct rtable *r)
 339 {
 340         struct rt_cache_iter_state *st = seq->private;
 341
 342         r = rcu_dereference_bh(r->dst.rt_next);
 343         while (!r) {
 344                 rcu_read_unlock_bh();
 345                 do {
 346                         if (--st->bucket < 0)
 347                                 return NULL;
 348                 } while (!rcu_dereference_raw(rt_hash_table[st->bucket].chain));
 349                 rcu_read_lock_bh();
 350                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 351         }
 352         return r;
 353 }
 354
 355 static struct rtable *rt_cache_get_next(struct seq_file *seq,
 356                                         struct rtable *r)
 357 {
 358         struct rt_cache_iter_state *st = seq->private;
 359         while ((r = __rt_cache_get_next(seq, r)) != NULL) {
 360                 if (dev_net(r->dst.dev) != seq_file_net(seq))
 361                         continue;
 362                 if (r->rt_genid == st->genid)
 363                         break;
 364         }
 365         return r;
 366 }
 367
 368 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
 369 {
 370         struct rtable *r = rt_cache_get_first(seq);
 371
 372         if (r)
 373                 while (pos && (r = rt_cache_get_next(seq, r)))
 374                         --pos;
 375         return pos ? NULL : r;
 376 }
 377
 378 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 379 {
 380         struct rt_cache_iter_state *st = seq->private;
 381         if (*pos)
 382                 return rt_cache_get_idx(seq, *pos - 1);
 383         st->genid = rt_genid(seq_file_net(seq));
 384         return SEQ_START_TOKEN;
 385 }
 386
 387 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 388 {
 389         struct rtable *r;
 390
 391         if (v == SEQ_START_TOKEN)
 392                 r = rt_cache_get_first(seq);
 393         else
 394                 r = rt_cache_get_next(seq, v);
 395         ++*pos;
 396         return r;
 397 }
 398
 399 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 400 {
 401         if (v && v != SEQ_START_TOKEN)
 402                 rcu_read_unlock_bh();
 403 }
 404
 405 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 406 {
 407         if (v == SEQ_START_TOKEN)
 408                 seq_printf(seq, "%-127s\n",
 409                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 410                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 411                            "HHUptod\tSpecDst");
 412         else {
 413                 struct rtable *r = v;
 414                 int len;
 415
 416                 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
 417                               "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
 418                         r->dst.dev ? r->dst.dev->name : "*",
 419                         (__force u32)r->rt_dst,
 420                         (__force u32)r->rt_gateway,
 421                         r->rt_flags, atomic_read(&r->dst.__refcnt),
 422                         r->dst.__use, 0, (__force u32)r->rt_src,
 423                         dst_metric_advmss(&r->dst) + 40,
 424                         dst_metric(&r->dst, RTAX_WINDOW),
 425                         (int)((dst_metric(&r->dst, RTAX_RTT) >> 3) +
 426                               dst_metric(&r->dst, RTAX_RTTVAR)),
 427                         r->rt_tos,
 428                         r->dst.hh ? atomic_read(&r->dst.hh->hh_refcnt) : -1,
 429                         r->dst.hh ? (r->dst.hh->hh_output ==
 430                                        dev_queue_xmit) : 0,
 431                         r->rt_spec_dst, &len);
 432
 433                 seq_printf(seq, "%*s\n", 127 - len, "");
 434         }
 435         return 0;
 436 }
 437
 438 static const struct seq_operations rt_cache_seq_ops = {
 439         .start  = rt_cache_seq_start,
 440         .next   = rt_cache_seq_next,
 441         .stop   = rt_cache_seq_stop,
 442         .show   = rt_cache_seq_show,
 443 };
 444
 445 static int rt_cache_seq_open(struct inode *inode, struct file *file)
 446 {
 447         return seq_open_net(inode, file, &rt_cache_seq_ops,
 448                         sizeof(struct rt_cache_iter_state));
 449 }
 450
 451 static const struct file_operations rt_cache_seq_fops = {
 452         .owner   = THIS_MODULE,
 453         .open    = rt_cache_seq_open,
 454         .read    = seq_read,
 455         .llseek  = seq_lseek,
 456         .release = seq_release_net,
 457 };
 458
 459
 460 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 461 {
 462         int cpu;
 463
 464         if (*pos == 0)
 465                 return SEQ_START_TOKEN;
 466
 467         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 468                 if (!cpu_possible(cpu))
 469                         continue;
 470                 *pos = cpu+1;
 471                 return &per_cpu(rt_cache_stat, cpu);
 472         }
 473         return NULL;
 474 }
 475
 476 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 477 {
 478         int cpu;
 479
 480         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 481                 if (!cpu_possible(cpu))
 482                         continue;
 483                 *pos = cpu+1;
 484                 return &per_cpu(rt_cache_stat, cpu);
 485         }
 486         return NULL;
 487
 488 }
 489
 490 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 491 {
 492
 493 }
 494
 495 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 496 {
 497         struct rt_cache_stat *st = v;
 498
 499         if (v == SEQ_START_TOKEN) {
 500                 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");
 501                 return 0;
 502         }
 503
 504         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 505                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
 506                    dst_entries_get_slow(&ipv4_dst_ops),
 507                    st->in_hit,
 508                    st->in_slow_tot,
 509                    st->in_slow_mc,
 510                    st->in_no_route,
 511                    st->in_brd,
 512                    st->in_martian_dst,
 513                    st->in_martian_src,
 514
 515                    st->out_hit,
 516                    st->out_slow_tot,
 517                    st->out_slow_mc,
 518
 519                    st->gc_total,
 520                    st->gc_ignored,
 521                    st->gc_goal_miss,
 522                    st->gc_dst_overflow,
 523                    st->in_hlist_search,
 524                    st->out_hlist_search
 525                 );
 526         return 0;
 527 }
 528
 529 static const struct seq_operations rt_cpu_seq_ops = {
 530         .start  = rt_cpu_seq_start,
 531         .next   = rt_cpu_seq_next,
 532         .stop   = rt_cpu_seq_stop,
 533         .show   = rt_cpu_seq_show,
 534 };
 535
 536
 537 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 538 {
 539         return seq_open(file, &rt_cpu_seq_ops);
 540 }
 541
 542 static const struct file_operations rt_cpu_seq_fops = {
 543         .owner   = THIS_MODULE,
 544         .open    = rt_cpu_seq_open,
 545         .read    = seq_read,
 546         .llseek  = seq_lseek,
 547         .release = seq_release,
 548 };
 549
 550 #ifdef CONFIG_IP_ROUTE_CLASSID
 551 static int rt_acct_proc_show(struct seq_file *m, void *v)
 552 {
 553         struct ip_rt_acct *dst, *src;
 554         unsigned int i, j;
 555
 556         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 557         if (!dst)
 558                 return -ENOMEM;
 559
 560         for_each_possible_cpu(i) {
 561                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 562                 for (j = 0; j < 256; j++) {
 563                         dst[j].o_bytes   += src[j].o_bytes;
 564                         dst[j].o_packets += src[j].o_packets;
 565                         dst[j].i_bytes   += src[j].i_bytes;
 566                         dst[j].i_packets += src[j].i_packets;
 567                 }
 568         }
 569
 570         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 571         kfree(dst);
 572         return 0;
 573 }
 574
 575 static int rt_acct_proc_open(struct inode *inode, struct file *file)
 576 {
 577         return single_open(file, rt_acct_proc_show, NULL);
 578 }
 579
 580 static const struct file_operations rt_acct_proc_fops = {
 581         .owner          = THIS_MODULE,
 582         .open           = rt_acct_proc_open,
 583         .read           = seq_read,
 584         .llseek         = seq_lseek,
 585         .release        = single_release,
 586 };
 587 #endif
 588
 589 static int __net_init ip_rt_do_proc_init(struct net *net)
 590 {
 591         struct proc_dir_entry *pde;
 592
 593         pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
 594                         &rt_cache_seq_fops);
 595         if (!pde)
 596                 goto err1;
 597
 598         pde = proc_create("rt_cache", S_IRUGO,
 599                           net->proc_net_stat, &rt_cpu_seq_fops);
 600         if (!pde)
 601                 goto err2;
 602
 603 #ifdef CONFIG_IP_ROUTE_CLASSID
 604         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
 605         if (!pde)
 606                 goto err3;
 607 #endif
 608         return 0;
 609
 610 #ifdef CONFIG_IP_ROUTE_CLASSID
 611 err3:
 612         remove_proc_entry("rt_cache", net->proc_net_stat);
 613 #endif
 614 err2:
 615         remove_proc_entry("rt_cache", net->proc_net);
 616 err1:
 617         return -ENOMEM;
 618 }
 619
 620 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 621 {
 622         remove_proc_entry("rt_cache", net->proc_net_stat);
 623         remove_proc_entry("rt_cache", net->proc_net);
 624 #ifdef CONFIG_IP_ROUTE_CLASSID
 625         remove_proc_entry("rt_acct", net->proc_net);
 626 #endif
 627 }
 628
 629 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 630         .init = ip_rt_do_proc_init,
 631         .exit = ip_rt_do_proc_exit,
 632 };
 633
 634 static int __init ip_rt_proc_init(void)
 635 {
 636         return register_pernet_subsys(&ip_rt_proc_ops);
 637 }
 638
 639 #else
 640 static inline int ip_rt_proc_init(void)
 641 {
 642         return 0;
 643 }
 644 #endif /* CONFIG_PROC_FS */
 645
 646 static inline void rt_free(struct rtable *rt)
 647 {
 648         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 649 }
 650
 651 static inline void rt_drop(struct rtable *rt)
 652 {
 653         ip_rt_put(rt);
 654         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 655 }
 656
 657 static inline int rt_fast_clean(struct rtable *rth)
 658 {
 659         /* Kill broadcast/multicast entries very aggresively, if they
 660            collide in hash table with more useful entries */
 661         return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
 662                 rt_is_input_route(rth) && rth->dst.rt_next;
 663 }
 664
 665 static inline int rt_valuable(struct rtable *rth)
 666 {
 667         return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
 668                 (rth->peer && rth->peer->pmtu_expires);
 669 }
 670
 671 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
 672 {
 673         unsigned long age;
 674         int ret = 0;
 675
 676         if (atomic_read(&rth->dst.__refcnt))
 677                 goto out;
 678
 679         age = jiffies - rth->dst.lastuse;
 680         if ((age <= tmo1 && !rt_fast_clean(rth)) ||
 681             (age <= tmo2 && rt_valuable(rth)))
 682                 goto out;
 683         ret = 1;
 684 out:    return ret;
 685 }
 686
 687 /* Bits of score are:
 688  * 31: very valuable
 689  * 30: not quite useless
 690  * 29..0: usage counter
 691  */
 692 static inline u32 rt_score(struct rtable *rt)
 693 {
 694         u32 score = jiffies - rt->dst.lastuse;
 695
 696         score = ~score & ~(3<<30);
 697
 698         if (rt_valuable(rt))
 699                 score |= (1<<31);
 700
 701         if (rt_is_output_route(rt) ||
 702             !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
 703                 score |= (1<<30);
 704
 705         return score;
 706 }
 707
 708 static inline bool rt_caching(const struct net *net)
 709 {
 710         return net->ipv4.current_rt_cache_rebuild_count <=
 711                 net->ipv4.sysctl_rt_cache_rebuild_count;
 712 }
 713
 714 static inline bool compare_hash_inputs(const struct rtable *rt1,
 715                                        const struct rtable *rt2)
 716 {
 717         return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
 718                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
 719                 (rt1->rt_iif ^ rt2->rt_iif)) == 0);
 720 }
 721
 722 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
 723 {
 724         return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
 725                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
 726                 (rt1->rt_mark ^ rt2->rt_mark) |
 727                 (rt1->rt_tos ^ rt2->rt_tos) |
 728                 (rt1->rt_oif ^ rt2->rt_oif) |
 729                 (rt1->rt_iif ^ rt2->rt_iif)) == 0;
 730 }
 731
 732 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
 733 {
 734         return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
 735 }
 736
 737 static inline int rt_is_expired(struct rtable *rth)
 738 {
 739         return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
 740 }
 741
 742 /*
 743  * Perform a full scan of hash table and free all entries.
 744  * Can be called by a softirq or a process.
 745  * In the later case, we want to be reschedule if necessary
 746  */
 747 static void rt_do_flush(struct net *net, int process_context)
 748 {
 749         unsigned int i;
 750         struct rtable *rth, *next;
 751
 752         for (i = 0; i <= rt_hash_mask; i++) {
 753                 struct rtable __rcu **pprev;
 754                 struct rtable *list;
 755
 756                 if (process_context && need_resched())
 757                         cond_resched();
 758                 rth = rcu_dereference_raw(rt_hash_table[i].chain);
 759                 if (!rth)
 760                         continue;
 761
 762                 spin_lock_bh(rt_hash_lock_addr(i));
 763
 764                 list = NULL;
 765                 pprev = &rt_hash_table[i].chain;
 766                 rth = rcu_dereference_protected(*pprev,
 767                         lockdep_is_held(rt_hash_lock_addr(i)));
 768
 769                 while (rth) {
 770                         next = rcu_dereference_protected(rth->dst.rt_next,
 771                                 lockdep_is_held(rt_hash_lock_addr(i)));
 772
 773                         if (!net ||
 774                             net_eq(dev_net(rth->dst.dev), net)) {
 775                                 rcu_assign_pointer(*pprev, next);
 776                                 rcu_assign_pointer(rth->dst.rt_next, list);
 777                                 list = rth;
 778                         } else {
 779                                 pprev = &rth->dst.rt_next;
 780                         }
 781                         rth = next;
 782                 }
 783
 784                 spin_unlock_bh(rt_hash_lock_addr(i));
 785
 786                 for (; list; list = next) {
 787                         next = rcu_dereference_protected(list->dst.rt_next, 1);
 788                         rt_free(list);
 789                 }
 790         }
 791 }
 792
 793 /*
 794  * While freeing expired entries, we compute average chain length
 795  * and standard deviation, using fixed-point arithmetic.
 796  * This to have an estimation of rt_chain_length_max
 797  *  rt_chain_length_max = max(elasticity, AVG + 4*SD)
 798  * We use 3 bits for frational part, and 29 (or 61) for magnitude.
 799  */
 800
 801 #define FRACT_BITS 3
 802 #define ONE (1UL << FRACT_BITS)
 803
 804 /*
 805  * Given a hash chain and an item in this hash chain,
 806  * find if a previous entry has the same hash_inputs
 807  * (but differs on tos, mark or oif)
 808  * Returns 0 if an alias is found.
 809  * Returns ONE if rth has no alias before itself.
 810  */
 811 static int has_noalias(const struct rtable *head, const struct rtable *rth)
 812 {
 813         const struct rtable *aux = head;
 814
 815         while (aux != rth) {
 816                 if (compare_hash_inputs(aux, rth))
 817                         return 0;
 818                 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
 819         }
 820         return ONE;
 821 }
 822
 823 /*
 824  * Perturbation of rt_genid by a small quantity [1..256]
 825  * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
 826  * many times (2^24) without giving recent rt_genid.
 827  * Jenkins hash is strong enough that litle changes of rt_genid are OK.
 828  */
 829 static void rt_cache_invalidate(struct net *net)
 830 {
 831         unsigned char shuffle;
 832
 833         get_random_bytes(&shuffle, sizeof(shuffle));
 834         atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
 835 }
 836
 837 /*
 838  * delay < 0  : invalidate cache (fast : entries will be deleted later)
 839  * delay >= 0 : invalidate & flush cache (can be long)
 840  */
 841 void rt_cache_flush(struct net *net, int delay)
 842 {
 843         rt_cache_invalidate(net);
 844         if (delay >= 0)
 845                 rt_do_flush(net, !in_softirq());
 846 }
 847
 848 /* Flush previous cache invalidated entries from the cache */
 849 void rt_cache_flush_batch(struct net *net)
 850 {
 851         rt_do_flush(net, !in_softirq());
 852 }
 853
 854 static void rt_emergency_hash_rebuild(struct net *net)
 855 {
 856         if (net_ratelimit())
 857                 printk(KERN_WARNING "Route hash chain too long!\n");
 858         rt_cache_invalidate(net);
 859 }
 860
 861 /*
 862    Short description of GC goals.
 863
 864    We want to build algorithm, which will keep routing cache
 865    at some equilibrium point, when number of aged off entries
 866    is kept approximately equal to newly generated ones.
 867
 868    Current expiration strength is variable "expire".
 869    We try to adjust it dynamically, so that if networking
 870    is idle expires is large enough to keep enough of warm entries,
 871    and when load increases it reduces to limit cache size.
 872  */
 873
 874 static int rt_garbage_collect(struct dst_ops *ops)
 875 {
 876         static unsigned long expire = RT_GC_TIMEOUT;
 877         static unsigned long last_gc;
 878         static int rover;
 879         static int equilibrium;
 880         struct rtable *rth;
 881         struct rtable __rcu **rthp;
 882         unsigned long now = jiffies;
 883         int goal;
 884         int entries = dst_entries_get_fast(&ipv4_dst_ops);
 885
 886         /*
 887          * Garbage collection is pretty expensive,
 888          * do not make it too frequently.
 889          */
 890
 891         RT_CACHE_STAT_INC(gc_total);
 892
 893         if (now - last_gc < ip_rt_gc_min_interval &&
 894             entries < ip_rt_max_size) {
 895                 RT_CACHE_STAT_INC(gc_ignored);
 896                 goto out;
 897         }
 898
 899         entries = dst_entries_get_slow(&ipv4_dst_ops);
 900         /* Calculate number of entries, which we want to expire now. */
 901         goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
 902         if (goal <= 0) {
 903                 if (equilibrium < ipv4_dst_ops.gc_thresh)
 904                         equilibrium = ipv4_dst_ops.gc_thresh;
 905                 goal = entries - equilibrium;
 906                 if (goal > 0) {
 907                         equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
 908                         goal = entries - equilibrium;
 909                 }
 910         } else {
 911                 /* We are in dangerous area. Try to reduce cache really
 912                  * aggressively.
 913                  */
 914                 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
 915                 equilibrium = entries - goal;
 916         }
 917
 918         if (now - last_gc >= ip_rt_gc_min_interval)
 919                 last_gc = now;
 920
 921         if (goal <= 0) {
 922                 equilibrium += goal;
 923                 goto work_done;
 924         }
 925
 926         do {
 927                 int i, k;
 928
 929                 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
 930                         unsigned long tmo = expire;
 931
 932                         k = (k + 1) & rt_hash_mask;
 933                         rthp = &rt_hash_table[k].chain;
 934                         spin_lock_bh(rt_hash_lock_addr(k));
 935                         while ((rth = rcu_dereference_protected(*rthp,
 936                                         lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
 937                                 if (!rt_is_expired(rth) &&
 938                                         !rt_may_expire(rth, tmo, expire)) {
 939                                         tmo >>= 1;
 940                                         rthp = &rth->dst.rt_next;
 941                                         continue;
 942                                 }
 943                                 *rthp = rth->dst.rt_next;
 944                                 rt_free(rth);
 945                                 goal--;
 946                         }
 947                         spin_unlock_bh(rt_hash_lock_addr(k));
 948                         if (goal <= 0)
 949                                 break;
 950                 }
 951                 rover = k;
 952
 953                 if (goal <= 0)
 954                         goto work_done;
 955
 956                 /* Goal is not achieved. We stop process if:
 957
 958                    - if expire reduced to zero. Otherwise, expire is halfed.
 959                    - if table is not full.
 960                    - if we are called from interrupt.
 961                    - jiffies check is just fallback/debug loop breaker.
 962                      We will not spin here for long time in any case.
 963                  */
 964
 965                 RT_CACHE_STAT_INC(gc_goal_miss);
 966
 967                 if (expire == 0)
 968                         break;
 969
 970                 expire >>= 1;
 971 #if RT_CACHE_DEBUG >= 2
 972                 printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
 973                                 dst_entries_get_fast(&ipv4_dst_ops), goal, i);
 974 #endif
 975
 976                 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
 977                         goto out;
 978         } while (!in_softirq() && time_before_eq(jiffies, now));
 979
 980         if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
 981                 goto out;
 982         if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
 983                 goto out;
 984         if (net_ratelimit())
 985                 printk(KERN_WARNING "dst cache overflow\n");
 986         RT_CACHE_STAT_INC(gc_dst_overflow);
 987         return 1;
 988
 989 work_done:
 990         expire += ip_rt_gc_min_interval;
 991         if (expire > ip_rt_gc_timeout ||
 992             dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
 993             dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
 994                 expire = ip_rt_gc_timeout;
 995 #if RT_CACHE_DEBUG >= 2
 996         printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
 997                         dst_entries_get_fast(&ipv4_dst_ops), goal, rover);
 998 #endif
 999 out:    return 0;
1000 }
1001
1002 /*
1003  * Returns number of entries in a hash chain that have different hash_inputs
1004  */
1005 static int slow_chain_length(const struct rtable *head)
1006 {
1007         int length = 0;
1008         const struct rtable *rth = head;
1009
1010         while (rth) {
1011                 length += has_noalias(head, rth);
1012                 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1013         }
1014         return length >> FRACT_BITS;
1015 }
1016
1017 static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt,
1018                                      struct sk_buff *skb, int ifindex)
1019 {
1020         struct rtable   *rth, *cand;
1021         struct rtable __rcu **rthp, **candp;
1022         unsigned long   now;
1023         u32             min_score;
1024         int             chain_length;
1025         int attempts = !in_softirq();
1026
1027 restart:
1028         chain_length = 0;
1029         min_score = ~(u32)0;
1030         cand = NULL;
1031         candp = NULL;
1032         now = jiffies;
1033
1034         if (!rt_caching(dev_net(rt->dst.dev))) {
1035                 /*
1036                  * If we're not caching, just tell the caller we
1037                  * were successful and don't touch the route.  The
1038                  * caller hold the sole reference to the cache entry, and
1039                  * it will be released when the caller is done with it.
1040                  * If we drop it here, the callers have no way to resolve routes
1041                  * when we're not caching.  Instead, just point *rp at rt, so
1042                  * the caller gets a single use out of the route
1043                  * Note that we do rt_free on this new route entry, so that
1044                  * once its refcount hits zero, we are still able to reap it
1045                  * (Thanks Alexey)
1046                  * Note: To avoid expensive rcu stuff for this uncached dst,
1047                  * we set DST_NOCACHE so that dst_release() can free dst without
1048                  * waiting a grace period.
1049                  */
1050
1051                 rt->dst.flags |= DST_NOCACHE;
1052                 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1053                         int err = arp_bind_neighbour(&rt->dst);
1054                         if (err) {
1055                                 if (net_ratelimit())
1056                                         printk(KERN_WARNING
1057                                             "Neighbour table failure & not caching routes.\n");
1058                                 ip_rt_put(rt);
1059                                 return ERR_PTR(err);
1060                         }
1061                 }
1062
1063                 goto skip_hashing;
1064         }
1065
1066         rthp = &rt_hash_table[hash].chain;
1067
1068         spin_lock_bh(rt_hash_lock_addr(hash));
1069         while ((rth = rcu_dereference_protected(*rthp,
1070                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1071                 if (rt_is_expired(rth)) {
1072                         *rthp = rth->dst.rt_next;
1073                         rt_free(rth);
1074                         continue;
1075                 }
1076                 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1077                         /* Put it first */
1078                         *rthp = rth->dst.rt_next;
1079                         /*
1080                          * Since lookup is lockfree, the deletion
1081                          * must be visible to another weakly ordered CPU before
1082                          * the insertion at the start of the hash chain.
1083                          */
1084                         rcu_assign_pointer(rth->dst.rt_next,
1085                                            rt_hash_table[hash].chain);
1086                         /*
1087                          * Since lookup is lockfree, the update writes
1088                          * must be ordered for consistency on SMP.
1089                          */
1090                         rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1091
1092                         dst_use(&rth->dst, now);
1093                         spin_unlock_bh(rt_hash_lock_addr(hash));
1094
1095                         rt_drop(rt);
1096                         if (skb)
1097                                 skb_dst_set(skb, &rth->dst);
1098                         return rth;
1099                 }
1100
1101                 if (!atomic_read(&rth->dst.__refcnt)) {
1102                         u32 score = rt_score(rth);
1103
1104                         if (score <= min_score) {
1105                                 cand = rth;
1106                                 candp = rthp;
1107                                 min_score = score;
1108                         }
1109                 }
1110
1111                 chain_length++;
1112
1113                 rthp = &rth->dst.rt_next;
1114         }
1115
1116         if (cand) {
1117                 /* ip_rt_gc_elasticity used to be average length of chain
1118                  * length, when exceeded gc becomes really aggressive.
1119                  *
1120                  * The second limit is less certain. At the moment it allows
1121                  * only 2 entries per bucket. We will see.
1122                  */
1123                 if (chain_length > ip_rt_gc_elasticity) {
1124                         *candp = cand->dst.rt_next;
1125                         rt_free(cand);
1126                 }
1127         } else {
1128                 if (chain_length > rt_chain_length_max &&
1129                     slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1130                         struct net *net = dev_net(rt->dst.dev);
1131                         int num = ++net->ipv4.current_rt_cache_rebuild_count;
1132                         if (!rt_caching(net)) {
1133                                 printk(KERN_WARNING "%s: %d rebuilds is over limit, route caching disabled\n",
1134                                         rt->dst.dev->name, num);
1135                         }
1136                         rt_emergency_hash_rebuild(net);
1137                         spin_unlock_bh(rt_hash_lock_addr(hash));
1138
1139                         hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1140                                         ifindex, rt_genid(net));
1141                         goto restart;
1142                 }
1143         }
1144
1145         /* Try to bind route to arp only if it is output
1146            route or unicast forwarding path.
1147          */
1148         if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
1149                 int err = arp_bind_neighbour(&rt->dst);
1150                 if (err) {
1151                         spin_unlock_bh(rt_hash_lock_addr(hash));
1152
1153                         if (err != -ENOBUFS) {
1154                                 rt_drop(rt);
1155                                 return ERR_PTR(err);
1156                         }
1157
1158                         /* Neighbour tables are full and nothing
1159                            can be released. Try to shrink route cache,
1160                            it is most likely it holds some neighbour records.
1161                          */
1162                         if (attempts-- > 0) {
1163                                 int saved_elasticity = ip_rt_gc_elasticity;
1164                                 int saved_int = ip_rt_gc_min_interval;
1165                                 ip_rt_gc_elasticity     = 1;
1166                                 ip_rt_gc_min_interval   = 0;
1167                                 rt_garbage_collect(&ipv4_dst_ops);
1168                                 ip_rt_gc_min_interval   = saved_int;
1169                                 ip_rt_gc_elasticity     = saved_elasticity;
1170                                 goto restart;
1171                         }
1172
1173                         if (net_ratelimit())
1174                                 printk(KERN_WARNING "ipv4: Neighbour table overflow.\n");
1175                         rt_drop(rt);
1176                         return ERR_PTR(-ENOBUFS);
1177                 }
1178         }
1179
1180         rt->dst.rt_next = rt_hash_table[hash].chain;
1181
1182 #if RT_CACHE_DEBUG >= 2
1183         if (rt->dst.rt_next) {
1184                 struct rtable *trt;
1185                 printk(KERN_DEBUG "rt_cache @%02x: %pI4",
1186                        hash, &rt->rt_dst);
1187                 for (trt = rt->dst.rt_next; trt; trt = trt->dst.rt_next)
1188                         printk(" . %pI4", &trt->rt_dst);
1189                 printk("\n");
1190         }
1191 #endif
1192         /*
1193          * Since lookup is lockfree, we must make sure
1194          * previous writes to rt are committed to memory
1195          * before making rt visible to other CPUS.
1196          */
1197         rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1198
1199         spin_unlock_bh(rt_hash_lock_addr(hash));
1200
1201 skip_hashing:
1202         if (skb)
1203                 skb_dst_set(skb, &rt->dst);
1204         return rt;
1205 }
1206
1207 static atomic_t __rt_peer_genid = ATOMIC_INIT(0);
1208
1209 static u32 rt_peer_genid(void)
1210 {
1211         return atomic_read(&__rt_peer_genid);
1212 }
1213
1214 void rt_bind_peer(struct rtable *rt, int create)
1215 {
1216         struct inet_peer *peer;
1217
1218         peer = inet_getpeer_v4(rt->rt_dst, create);
1219
1220         if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
1221                 inet_putpeer(peer);
1222         else
1223                 rt->rt_peer_genid = rt_peer_genid();
1224 }
1225
1226 /*
1227  * Peer allocation may fail only in serious out-of-memory conditions.  However
1228  * we still can generate some output.
1229  * Random ID selection looks a bit dangerous because we have no chances to
1230  * select ID being unique in a reasonable period of time.
1231  * But broken packet identifier may be better than no packet at all.
1232  */
1233 static void ip_select_fb_ident(struct iphdr *iph)
1234 {
1235         static DEFINE_SPINLOCK(ip_fb_id_lock);
1236         static u32 ip_fallback_id;
1237         u32 salt;
1238
1239         spin_lock_bh(&ip_fb_id_lock);
1240         salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1241         iph->id = htons(salt & 0xFFFF);
1242         ip_fallback_id = salt;
1243         spin_unlock_bh(&ip_fb_id_lock);
1244 }
1245
1246 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1247 {
1248         struct rtable *rt = (struct rtable *) dst;
1249
1250         if (rt) {
1251                 if (rt->peer == NULL)
1252                         rt_bind_peer(rt, 1);
1253
1254                 /* If peer is attached to destination, it is never detached,
1255                    so that we need not to grab a lock to dereference it.
1256                  */
1257                 if (rt->peer) {
1258                         iph->id = htons(inet_getid(rt->peer, more));
1259                         return;
1260                 }
1261         } else
1262                 printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1263                        __builtin_return_address(0));
1264
1265         ip_select_fb_ident(iph);
1266 }
1267 EXPORT_SYMBOL(__ip_select_ident);
1268
1269 static void rt_del(unsigned hash, struct rtable *rt)
1270 {
1271         struct rtable __rcu **rthp;
1272         struct rtable *aux;
1273
1274         rthp = &rt_hash_table[hash].chain;
1275         spin_lock_bh(rt_hash_lock_addr(hash));
1276         ip_rt_put(rt);
1277         while ((aux = rcu_dereference_protected(*rthp,
1278                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1279                 if (aux == rt || rt_is_expired(aux)) {
1280                         *rthp = aux->dst.rt_next;
1281                         rt_free(aux);
1282                         continue;
1283                 }
1284                 rthp = &aux->dst.rt_next;
1285         }
1286         spin_unlock_bh(rt_hash_lock_addr(hash));
1287 }
1288
1289 /* called in rcu_read_lock() section */
1290 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
1291                     __be32 saddr, struct net_device *dev)
1292 {
1293         struct in_device *in_dev = __in_dev_get_rcu(dev);
1294         struct inet_peer *peer;
1295         struct net *net;
1296
1297         if (!in_dev)
1298                 return;
1299
1300         net = dev_net(dev);
1301         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1302             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1303             ipv4_is_zeronet(new_gw))
1304                 goto reject_redirect;
1305
1306         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1307                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1308                         goto reject_redirect;
1309                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1310                         goto reject_redirect;
1311         } else {
1312                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1313                         goto reject_redirect;
1314         }
1315
1316         peer = inet_getpeer_v4(daddr, 1);
1317         if (peer) {
1318                 peer->redirect_learned.a4 = new_gw;
1319
1320                 inet_putpeer(peer);
1321
1322                 atomic_inc(&__rt_peer_genid);
1323         }
1324         return;
1325
1326 reject_redirect:
1327 #ifdef CONFIG_IP_ROUTE_VERBOSE
1328         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
1329                 printk(KERN_INFO "Redirect from %pI4 on %s about %pI4 ignored.\n"
1330                         "  Advised path = %pI4 -> %pI4\n",
1331                        &old_gw, dev->name, &new_gw,
1332                        &saddr, &daddr);
1333 #endif
1334         ;
1335 }
1336
1337 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1338 {
1339         struct rtable *rt = (struct rtable *)dst;
1340         struct dst_entry *ret = dst;
1341
1342         if (rt) {
1343                 if (dst->obsolete > 0) {
1344                         ip_rt_put(rt);
1345                         ret = NULL;
1346                 } else if (rt->rt_flags & RTCF_REDIRECTED) {
1347                         unsigned hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1348                                                 rt->rt_oif,
1349                                                 rt_genid(dev_net(dst->dev)));
1350 #if RT_CACHE_DEBUG >= 1
1351                         printk(KERN_DEBUG "ipv4_negative_advice: redirect to %pI4/%02x dropped\n",
1352                                 &rt->rt_dst, rt->rt_tos);
1353 #endif
1354                         rt_del(hash, rt);
1355                         ret = NULL;
1356                 } else if (rt->peer &&
1357                            rt->peer->pmtu_expires &&
1358                            time_after_eq(jiffies, rt->peer->pmtu_expires)) {
1359                         unsigned long orig = rt->peer->pmtu_expires;
1360
1361                         if (cmpxchg(&rt->peer->pmtu_expires, orig, 0) == orig)
1362                                 dst_metric_set(dst, RTAX_MTU,
1363                                                rt->peer->pmtu_orig);
1364                 }
1365         }
1366         return ret;
1367 }
1368
1369 /*
1370  * Algorithm:
1371  *      1. The first ip_rt_redirect_number redirects are sent
1372  *         with exponential backoff, then we stop sending them at all,
1373  *         assuming that the host ignores our redirects.
1374  *      2. If we did not see packets requiring redirects
1375  *         during ip_rt_redirect_silence, we assume that the host
1376  *         forgot redirected route and start to send redirects again.
1377  *
1378  * This algorithm is much cheaper and more intelligent than dumb load limiting
1379  * in icmp.c.
1380  *
1381  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1382  * and "frag. need" (breaks PMTU discovery) in icmp.c.
1383  */
1384
1385 void ip_rt_send_redirect(struct sk_buff *skb)
1386 {
1387         struct rtable *rt = skb_rtable(skb);
1388         struct in_device *in_dev;
1389         struct inet_peer *peer;
1390         int log_martians;
1391
1392         rcu_read_lock();
1393         in_dev = __in_dev_get_rcu(rt->dst.dev);
1394         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1395                 rcu_read_unlock();
1396                 return;
1397         }
1398         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1399         rcu_read_unlock();
1400
1401         if (!rt->peer)
1402                 rt_bind_peer(rt, 1);
1403         peer = rt->peer;
1404         if (!peer) {
1405                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1406                 return;
1407         }
1408
1409         /* No redirected packets during ip_rt_redirect_silence;
1410          * reset the algorithm.
1411          */
1412         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1413                 peer->rate_tokens = 0;
1414
1415         /* Too many ignored redirects; do not send anything
1416          * set dst.rate_last to the last seen redirected packet.
1417          */
1418         if (peer->rate_tokens >= ip_rt_redirect_number) {
1419                 peer->rate_last = jiffies;
1420                 return;
1421         }
1422
1423         /* Check for load limit; set rate_last to the latest sent
1424          * redirect.
1425          */
1426         if (peer->rate_tokens == 0 ||
1427             time_after(jiffies,
1428                        (peer->rate_last +
1429                         (ip_rt_redirect_load << peer->rate_tokens)))) {
1430                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1431                 peer->rate_last = jiffies;
1432                 ++peer->rate_tokens;
1433 #ifdef CONFIG_IP_ROUTE_VERBOSE
1434                 if (log_martians &&
1435                     peer->rate_tokens == ip_rt_redirect_number &&
1436                     net_ratelimit())
1437                         printk(KERN_WARNING "host %pI4/if%d ignores redirects for %pI4 to %pI4.\n",
1438                                 &rt->rt_src, rt->rt_iif,
1439                                 &rt->rt_dst, &rt->rt_gateway);
1440 #endif
1441         }
1442 }
1443
1444 static int ip_error(struct sk_buff *skb)
1445 {
1446         struct rtable *rt = skb_rtable(skb);
1447         struct inet_peer *peer;
1448         unsigned long now;
1449         bool send;
1450         int code;
1451
1452         switch (rt->dst.error) {
1453                 case EINVAL:
1454                 default:
1455                         goto out;
1456                 case EHOSTUNREACH:
1457                         code = ICMP_HOST_UNREACH;
1458                         break;
1459                 case ENETUNREACH:
1460                         code = ICMP_NET_UNREACH;
1461                         IP_INC_STATS_BH(dev_net(rt->dst.dev),
1462                                         IPSTATS_MIB_INNOROUTES);
1463                         break;
1464                 case EACCES:
1465                         code = ICMP_PKT_FILTERED;
1466                         break;
1467         }
1468
1469         if (!rt->peer)
1470                 rt_bind_peer(rt, 1);
1471         peer = rt->peer;
1472
1473         send = true;
1474         if (peer) {
1475                 now = jiffies;
1476                 peer->rate_tokens += now - peer->rate_last;
1477                 if (peer->rate_tokens > ip_rt_error_burst)
1478                         peer->rate_tokens = ip_rt_error_burst;
1479                 peer->rate_last = now;
1480                 if (peer->rate_tokens >= ip_rt_error_cost)
1481                         peer->rate_tokens -= ip_rt_error_cost;
1482                 else
1483                         send = false;
1484         }
1485         if (send)
1486                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1487
1488 out:    kfree_skb(skb);
1489         return 0;
1490 }
1491
1492 /*
1493  *      The last two values are not from the RFC but
1494  *      are needed for AMPRnet AX.25 paths.
1495  */
1496
1497 static const unsigned short mtu_plateau[] =
1498 {32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
1499
1500 static inline unsigned short guess_mtu(unsigned short old_mtu)
1501 {
1502         int i;
1503
1504         for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
1505                 if (old_mtu > mtu_plateau[i])
1506                         return mtu_plateau[i];
1507         return 68;
1508 }
1509
1510 unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
1511                                  unsigned short new_mtu,
1512                                  struct net_device *dev)
1513 {
1514         unsigned short old_mtu = ntohs(iph->tot_len);
1515         unsigned short est_mtu = 0;
1516         struct inet_peer *peer;
1517
1518         peer = inet_getpeer_v4(iph->daddr, 1);
1519         if (peer) {
1520                 unsigned short mtu = new_mtu;
1521
1522                 if (new_mtu < 68 || new_mtu >= old_mtu) {
1523                         /* BSD 4.2 derived systems incorrectly adjust
1524                          * tot_len by the IP header length, and report
1525                          * a zero MTU in the ICMP message.
1526                          */
1527                         if (mtu == 0 &&
1528                             old_mtu >= 68 + (iph->ihl << 2))
1529                                 old_mtu -= iph->ihl << 2;
1530                         mtu = guess_mtu(old_mtu);
1531                 }
1532
1533                 if (mtu < ip_rt_min_pmtu)
1534                         mtu = ip_rt_min_pmtu;
1535                 if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
1536                         unsigned long pmtu_expires;
1537
1538                         pmtu_expires = jiffies + ip_rt_mtu_expires;
1539                         if (!pmtu_expires)
1540                                 pmtu_expires = 1UL;
1541
1542                         est_mtu = mtu;
1543                         peer->pmtu_learned = mtu;
1544                         peer->pmtu_expires = pmtu_expires;
1545                 }
1546
1547                 inet_putpeer(peer);
1548
1549                 atomic_inc(&__rt_peer_genid);
1550         }
1551         return est_mtu ? : new_mtu;
1552 }
1553
1554 static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
1555 {
1556         unsigned long expires = peer->pmtu_expires;
1557
1558         if (time_before(jiffies, expires)) {
1559                 u32 orig_dst_mtu = dst_mtu(dst);
1560                 if (peer->pmtu_learned < orig_dst_mtu) {
1561                         if (!peer->pmtu_orig)
1562                                 peer->pmtu_orig = dst_metric_raw(dst, RTAX_MTU);
1563                         dst_metric_set(dst, RTAX_MTU, peer->pmtu_learned);
1564                 }
1565         } else if (cmpxchg(&peer->pmtu_expires, expires, 0) == expires)
1566                 dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
1567 }
1568
1569 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1570 {
1571         struct rtable *rt = (struct rtable *) dst;
1572         struct inet_peer *peer;
1573
1574         dst_confirm(dst);
1575
1576         if (!rt->peer)
1577                 rt_bind_peer(rt, 1);
1578         peer = rt->peer;
1579         if (peer) {
1580                 if (mtu < ip_rt_min_pmtu)
1581                         mtu = ip_rt_min_pmtu;
1582                 if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
1583                         unsigned long pmtu_expires;
1584
1585                         pmtu_expires = jiffies + ip_rt_mtu_expires;
1586                         if (!pmtu_expires)
1587                                 pmtu_expires = 1UL;
1588
1589                         peer->pmtu_learned = mtu;
1590                         peer->pmtu_expires = pmtu_expires;
1591
1592                         atomic_inc(&__rt_peer_genid);
1593                         rt->rt_peer_genid = rt_peer_genid();
1594                 }
1595                 check_peer_pmtu(dst, peer);
1596         }
1597 }
1598
1599 static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
1600 {
1601         struct rtable *rt = (struct rtable *) dst;
1602         __be32 orig_gw = rt->rt_gateway;
1603
1604         dst_confirm(&rt->dst);
1605
1606         neigh_release(rt->dst.neighbour);
1607         rt->dst.neighbour = NULL;
1608
1609         rt->rt_gateway = peer->redirect_learned.a4;
1610         if (arp_bind_neighbour(&rt->dst) ||
1611             !(rt->dst.neighbour->nud_state & NUD_VALID)) {
1612                 if (rt->dst.neighbour)
1613                         neigh_event_send(rt->dst.neighbour, NULL);
1614                 rt->rt_gateway = orig_gw;
1615                 return -EAGAIN;
1616         } else {
1617                 rt->rt_flags |= RTCF_REDIRECTED;
1618                 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE,
1619                                         rt->dst.neighbour);
1620         }
1621         return 0;
1622 }
1623
1624 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1625 {
1626         struct rtable *rt = (struct rtable *) dst;
1627
1628         if (rt_is_expired(rt))
1629                 return NULL;
1630         if (rt->rt_peer_genid != rt_peer_genid()) {
1631                 struct inet_peer *peer;
1632
1633                 if (!rt->peer)
1634                         rt_bind_peer(rt, 0);
1635
1636                 peer = rt->peer;
1637                 if (peer && peer->pmtu_expires)
1638                         check_peer_pmtu(dst, peer);
1639
1640                 if (peer && peer->redirect_learned.a4 &&
1641                     peer->redirect_learned.a4 != rt->rt_gateway) {
1642                         if (check_peer_redir(dst, peer))
1643                                 return NULL;
1644                 }
1645
1646                 rt->rt_peer_genid = rt_peer_genid();
1647         }
1648         return dst;
1649 }
1650
1651 static void ipv4_dst_destroy(struct dst_entry *dst)
1652 {
1653         struct rtable *rt = (struct rtable *) dst;
1654         struct inet_peer *peer = rt->peer;
1655
1656         if (rt->fi) {
1657                 fib_info_put(rt->fi);
1658                 rt->fi = NULL;
1659         }
1660         if (peer) {
1661                 rt->peer = NULL;
1662                 inet_putpeer(peer);
1663         }
1664 }
1665
1666
1667 static void ipv4_link_failure(struct sk_buff *skb)
1668 {
1669         struct rtable *rt;
1670
1671         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1672
1673         rt = skb_rtable(skb);
1674         if (rt &&
1675             rt->peer &&
1676             rt->peer->pmtu_expires) {
1677                 unsigned long orig = rt->peer->pmtu_expires;
1678
1679                 if (cmpxchg(&rt->peer->pmtu_expires, orig, 0) == orig)
1680                         dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig);
1681         }
1682 }
1683
1684 static int ip_rt_bug(struct sk_buff *skb)
1685 {
1686         printk(KERN_DEBUG "ip_rt_bug: %pI4 -> %pI4, %s\n",
1687                 &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1688                 skb->dev ? skb->dev->name : "?");
1689         kfree_skb(skb);
1690         return 0;
1691 }
1692
1693 /*
1694    We do not cache source address of outgoing interface,
1695    because it is used only by IP RR, TS and SRR options,
1696    so that it out of fast path.
1697
1698    BTW remember: "addr" is allowed to be not aligned
1699    in IP options!
1700  */
1701
1702 void ip_rt_get_source(u8 *addr, struct rtable *rt)
1703 {
1704         __be32 src;
1705         struct fib_result res;
1706
1707         if (rt_is_output_route(rt))
1708                 src = rt->rt_src;
1709         else {
1710                 struct flowi4 fl4 = {
1711                         .daddr = rt->rt_key_dst,
1712                         .saddr = rt->rt_key_src,
1713                         .flowi4_tos = rt->rt_tos,
1714                         .flowi4_oif = rt->rt_oif,
1715                         .flowi4_iif = rt->rt_iif,
1716                         .flowi4_mark = rt->rt_mark,
1717                 };
1718
1719                 rcu_read_lock();
1720                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1721                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1722                 else
1723                         src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1724                                         RT_SCOPE_UNIVERSE);
1725                 rcu_read_unlock();
1726         }
1727         memcpy(addr, &src, 4);
1728 }
1729
1730 #ifdef CONFIG_IP_ROUTE_CLASSID
1731 static void set_class_tag(struct rtable *rt, u32 tag)
1732 {
1733         if (!(rt->dst.tclassid & 0xFFFF))
1734                 rt->dst.tclassid |= tag & 0xFFFF;
1735         if (!(rt->dst.tclassid & 0xFFFF0000))
1736                 rt->dst.tclassid |= tag & 0xFFFF0000;
1737 }
1738 #endif
1739
1740 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1741 {
1742         unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1743
1744         if (advmss == 0) {
1745                 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1746                                ip_rt_min_advmss);
1747                 if (advmss > 65535 - 40)
1748                         advmss = 65535 - 40;
1749         }
1750         return advmss;
1751 }
1752
1753 static unsigned int ipv4_default_mtu(const struct dst_entry *dst)
1754 {
1755         unsigned int mtu = dst->dev->mtu;
1756
1757         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1758                 const struct rtable *rt = (const struct rtable *) dst;
1759
1760                 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1761                         mtu = 576;
1762         }
1763
1764         if (mtu > IP_MAX_MTU)
1765                 mtu = IP_MAX_MTU;
1766
1767         return mtu;
1768 }
1769
1770 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *oldflp4,
1771                             struct fib_info *fi)
1772 {
1773         struct inet_peer *peer;
1774         int create = 0;
1775
1776         /* If a peer entry exists for this destination, we must hook
1777          * it up in order to get at cached metrics.
1778          */
1779         if (oldflp4 && (oldflp4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
1780                 create = 1;
1781
1782         rt->peer = peer = inet_getpeer_v4(rt->rt_dst, create);
1783         if (peer) {
1784                 rt->rt_peer_genid = rt_peer_genid();
1785                 if (inet_metrics_new(peer))
1786                         memcpy(peer->metrics, fi->fib_metrics,
1787                                sizeof(u32) * RTAX_MAX);
1788                 dst_init_metrics(&rt->dst, peer->metrics, false);
1789
1790                 if (peer->pmtu_expires)
1791                         check_peer_pmtu(&rt->dst, peer);
1792                 if (peer->redirect_learned.a4 &&
1793                     peer->redirect_learned.a4 != rt->rt_gateway) {
1794                         rt->rt_gateway = peer->redirect_learned.a4;
1795                         rt->rt_flags |= RTCF_REDIRECTED;
1796                 }
1797         } else {
1798                 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1799                         rt->fi = fi;
1800                         atomic_inc(&fi->fib_clntref);
1801                 }
1802                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1803         }
1804 }
1805
1806 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *oldflp4,
1807                            const struct fib_result *res,
1808                            struct fib_info *fi, u16 type, u32 itag)
1809 {
1810         struct dst_entry *dst = &rt->dst;
1811
1812         if (fi) {
1813                 if (FIB_RES_GW(*res) &&
1814                     FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1815                         rt->rt_gateway = FIB_RES_GW(*res);
1816                 rt_init_metrics(rt, oldflp4, fi);
1817 #ifdef CONFIG_IP_ROUTE_CLASSID
1818                 dst->tclassid = FIB_RES_NH(*res).nh_tclassid;
1819 #endif
1820         }
1821
1822         if (dst_mtu(dst) > IP_MAX_MTU)
1823                 dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU);
1824         if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40)
1825                 dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40);
1826
1827 #ifdef CONFIG_IP_ROUTE_CLASSID
1828 #ifdef CONFIG_IP_MULTIPLE_TABLES
1829         set_class_tag(rt, fib_rules_tclass(res));
1830 #endif
1831         set_class_tag(rt, itag);
1832 #endif
1833         rt->rt_type = type;
1834 }
1835
1836 static struct rtable *rt_dst_alloc(bool nopolicy, bool noxfrm)
1837 {
1838         struct rtable *rt = dst_alloc(&ipv4_dst_ops, 1);
1839         if (rt) {
1840                 rt->dst.obsolete = -1;
1841
1842                 rt->dst.flags = DST_HOST |
1843                         (nopolicy ? DST_NOPOLICY : 0) |
1844                         (noxfrm ? DST_NOXFRM : 0);
1845         }
1846         return rt;
1847 }
1848
1849 /* called in rcu_read_lock() section */
1850 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1851                                 u8 tos, struct net_device *dev, int our)
1852 {
1853         unsigned int hash;
1854         struct rtable *rth;
1855         __be32 spec_dst;
1856         struct in_device *in_dev = __in_dev_get_rcu(dev);
1857         u32 itag = 0;
1858         int err;
1859
1860         /* Primary sanity checks. */
1861
1862         if (in_dev == NULL)
1863                 return -EINVAL;
1864
1865         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1866             ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
1867                 goto e_inval;
1868
1869         if (ipv4_is_zeronet(saddr)) {
1870                 if (!ipv4_is_local_multicast(daddr))
1871                         goto e_inval;
1872                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
1873         } else {
1874                 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
1875                                           &itag, 0);
1876                 if (err < 0)
1877                         goto e_err;
1878         }
1879         rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1880         if (!rth)
1881                 goto e_nobufs;
1882
1883         rth->dst.output = ip_rt_bug;
1884
1885         rth->rt_key_dst = daddr;
1886         rth->rt_dst     = daddr;
1887         rth->rt_tos     = tos;
1888         rth->rt_mark    = skb->mark;
1889         rth->rt_key_src = saddr;
1890         rth->rt_src     = saddr;
1891 #ifdef CONFIG_IP_ROUTE_CLASSID
1892         rth->dst.tclassid = itag;
1893 #endif
1894         rth->rt_iif     = dev->ifindex;
1895         rth->dst.dev    = init_net.loopback_dev;
1896         dev_hold(rth->dst.dev);
1897         rth->rt_oif     = 0;
1898         rth->rt_gateway = daddr;
1899         rth->rt_spec_dst= spec_dst;
1900         rth->rt_genid   = rt_genid(dev_net(dev));
1901         rth->rt_flags   = RTCF_MULTICAST;
1902         rth->rt_type    = RTN_MULTICAST;
1903         if (our) {
1904                 rth->dst.input= ip_local_deliver;
1905                 rth->rt_flags |= RTCF_LOCAL;
1906         }
1907
1908 #ifdef CONFIG_IP_MROUTE
1909         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1910                 rth->dst.input = ip_mr_input;
1911 #endif
1912         RT_CACHE_STAT_INC(in_slow_mc);
1913
1914         hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
1915         rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
1916         err = 0;
1917         if (IS_ERR(rth))
1918                 err = PTR_ERR(rth);
1919
1920 e_nobufs:
1921         return -ENOBUFS;
1922 e_inval:
1923         return -EINVAL;
1924 e_err:
1925         return err;
1926 }
1927
1928
1929 static void ip_handle_martian_source(struct net_device *dev,
1930                                      struct in_device *in_dev,
1931                                      struct sk_buff *skb,
1932                                      __be32 daddr,
1933                                      __be32 saddr)
1934 {
1935         RT_CACHE_STAT_INC(in_martian_src);
1936 #ifdef CONFIG_IP_ROUTE_VERBOSE
1937         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1938                 /*
1939                  *      RFC1812 recommendation, if source is martian,
1940                  *      the only hint is MAC header.
1941                  */
1942                 printk(KERN_WARNING "martian source %pI4 from %pI4, on dev %s\n",
1943                         &daddr, &saddr, dev->name);
1944                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1945                         int i;
1946                         const unsigned char *p = skb_mac_header(skb);
1947                         printk(KERN_WARNING "ll header: ");
1948                         for (i = 0; i < dev->hard_header_len; i++, p++) {
1949                                 printk("%02x", *p);
1950                                 if (i < (dev->hard_header_len - 1))
1951                                         printk(":");
1952                         }
1953                         printk("\n");
1954                 }
1955         }
1956 #endif
1957 }
1958
1959 /* called in rcu_read_lock() section */
1960 static int __mkroute_input(struct sk_buff *skb,
1961                            const struct fib_result *res,
1962                            struct in_device *in_dev,
1963                            __be32 daddr, __be32 saddr, u32 tos,
1964                            struct rtable **result)
1965 {
1966         struct rtable *rth;
1967         int err;
1968         struct in_device *out_dev;
1969         unsigned int flags = 0;
1970         __be32 spec_dst;
1971         u32 itag;
1972
1973         /* get a working reference to the output device */
1974         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1975         if (out_dev == NULL) {
1976                 if (net_ratelimit())
1977                         printk(KERN_CRIT "Bug in ip_route_input" \
1978                                "_slow(). Please, report\n");
1979                 return -EINVAL;
1980         }
1981
1982
1983         err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
1984                                   in_dev->dev, &spec_dst, &itag, skb->mark);
1985         if (err < 0) {
1986                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1987                                          saddr);
1988
1989                 goto cleanup;
1990         }
1991
1992         if (err)
1993                 flags |= RTCF_DIRECTSRC;
1994
1995         if (out_dev == in_dev && err &&
1996             (IN_DEV_SHARED_MEDIA(out_dev) ||
1997              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1998                 flags |= RTCF_DOREDIRECT;
1999
2000         if (skb->protocol != htons(ETH_P_IP)) {
2001                 /* Not IP (i.e. ARP). Do not create route, if it is
2002                  * invalid for proxy arp. DNAT routes are always valid.
2003                  *
2004                  * Proxy arp feature have been extended to allow, ARP
2005                  * replies back to the same interface, to support
2006                  * Private VLAN switch technologies. See arp.c.
2007                  */
2008                 if (out_dev == in_dev &&
2009                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
2010                         err = -EINVAL;
2011                         goto cleanup;
2012                 }
2013         }
2014
2015         rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY),
2016                            IN_DEV_CONF_GET(out_dev, NOXFRM));
2017         if (!rth) {
2018                 err = -ENOBUFS;
2019                 goto cleanup;
2020         }
2021
2022         rth->rt_key_dst = daddr;
2023         rth->rt_dst     = daddr;
2024         rth->rt_tos     = tos;
2025         rth->rt_mark    = skb->mark;
2026         rth->rt_key_src = saddr;
2027         rth->rt_src     = saddr;
2028         rth->rt_gateway = daddr;
2029         rth->rt_iif     = in_dev->dev->ifindex;
2030         rth->dst.dev    = (out_dev)->dev;
2031         dev_hold(rth->dst.dev);
2032         rth->rt_oif     = 0;
2033         rth->rt_spec_dst= spec_dst;
2034
2035         rth->dst.input = ip_forward;
2036         rth->dst.output = ip_output;
2037         rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
2038
2039         rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
2040
2041         rth->rt_flags = flags;
2042
2043         *result = rth;
2044         err = 0;
2045  cleanup:
2046         return err;
2047 }
2048
2049 static int ip_mkroute_input(struct sk_buff *skb,
2050                             struct fib_result *res,
2051                             const struct flowi4 *fl4,
2052                             struct in_device *in_dev,
2053                             __be32 daddr, __be32 saddr, u32 tos)
2054 {
2055         struct rtable* rth = NULL;
2056         int err;
2057         unsigned hash;
2058
2059 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2060         if (res->fi && res->fi->fib_nhs > 1)
2061                 fib_select_multipath(res);
2062 #endif
2063
2064         /* create a routing cache entry */
2065         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
2066         if (err)
2067                 return err;
2068
2069         /* put it into the cache */
2070         hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
2071                        rt_genid(dev_net(rth->dst.dev)));
2072         rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
2073         if (IS_ERR(rth))
2074                 return PTR_ERR(rth);
2075         return 0;
2076 }
2077
2078 /*
2079  *      NOTE. We drop all the packets that has local source
2080  *      addresses, because every properly looped back packet
2081  *      must have correct destination already attached by output routine.
2082  *
2083  *      Such approach solves two big problems:
2084  *      1. Not simplex devices are handled properly.
2085  *      2. IP spoofing attempts are filtered with 100% of guarantee.
2086  *      called with rcu_read_lock()
2087  */
2088
2089 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2090                                u8 tos, struct net_device *dev)
2091 {
2092         struct fib_result res;
2093         struct in_device *in_dev = __in_dev_get_rcu(dev);
2094         struct flowi4   fl4;
2095         unsigned        flags = 0;
2096         u32             itag = 0;
2097         struct rtable * rth;
2098         unsigned        hash;
2099         __be32          spec_dst;
2100         int             err = -EINVAL;
2101         struct net    * net = dev_net(dev);
2102
2103         /* IP on this device is disabled. */
2104
2105         if (!in_dev)
2106                 goto out;
2107
2108         /* Check for the most weird martians, which can be not detected
2109            by fib_lookup.
2110          */
2111
2112         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
2113             ipv4_is_loopback(saddr))
2114                 goto martian_source;
2115
2116         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2117                 goto brd_input;
2118
2119         /* Accept zero addresses only to limited broadcast;
2120          * I even do not know to fix it or not. Waiting for complains :-)
2121          */
2122         if (ipv4_is_zeronet(saddr))
2123                 goto martian_source;
2124
2125         if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr))
2126                 goto martian_destination;
2127
2128         /*
2129          *      Now we are ready to route packet.
2130          */
2131         fl4.flowi4_oif = 0;
2132         fl4.flowi4_iif = dev->ifindex;
2133         fl4.flowi4_mark = skb->mark;
2134         fl4.flowi4_tos = tos;
2135         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2136         fl4.daddr = daddr;
2137         fl4.saddr = saddr;
2138         err = fib_lookup(net, &fl4, &res);
2139         if (err != 0) {
2140                 if (!IN_DEV_FORWARD(in_dev))
2141                         goto e_hostunreach;
2142                 goto no_route;
2143         }
2144
2145         RT_CACHE_STAT_INC(in_slow_tot);
2146
2147         if (res.type == RTN_BROADCAST)
2148                 goto brd_input;
2149
2150         if (res.type == RTN_LOCAL) {
2151                 err = fib_validate_source(saddr, daddr, tos,
2152                                           net->loopback_dev->ifindex,
2153                                           dev, &spec_dst, &itag, skb->mark);
2154                 if (err < 0)
2155                         goto martian_source_keep_err;
2156                 if (err)
2157                         flags |= RTCF_DIRECTSRC;
2158                 spec_dst = daddr;
2159                 goto local_input;
2160         }
2161
2162         if (!IN_DEV_FORWARD(in_dev))
2163                 goto e_hostunreach;
2164         if (res.type != RTN_UNICAST)
2165                 goto martian_destination;
2166
2167         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2168 out:    return err;
2169
2170 brd_input:
2171         if (skb->protocol != htons(ETH_P_IP))
2172                 goto e_inval;
2173
2174         if (ipv4_is_zeronet(saddr))
2175                 spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
2176         else {
2177                 err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
2178                                           &itag, skb->mark);
2179                 if (err < 0)
2180                         goto martian_source_keep_err;
2181                 if (err)
2182                         flags |= RTCF_DIRECTSRC;
2183         }
2184         flags |= RTCF_BROADCAST;
2185         res.type = RTN_BROADCAST;
2186         RT_CACHE_STAT_INC(in_brd);
2187
2188 local_input:
2189         rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2190         if (!rth)
2191                 goto e_nobufs;
2192
2193         rth->dst.output= ip_rt_bug;
2194         rth->rt_genid = rt_genid(net);
2195
2196         rth->rt_key_dst = daddr;
2197         rth->rt_dst     = daddr;
2198         rth->rt_tos     = tos;
2199         rth->rt_mark    = skb->mark;
2200         rth->rt_key_src = saddr;
2201         rth->rt_src     = saddr;
2202 #ifdef CONFIG_IP_ROUTE_CLASSID
2203         rth->dst.tclassid = itag;
2204 #endif
2205         rth->rt_iif     = dev->ifindex;
2206         rth->dst.dev    = net->loopback_dev;
2207         dev_hold(rth->dst.dev);
2208         rth->rt_gateway = daddr;
2209         rth->rt_spec_dst= spec_dst;
2210         rth->dst.input= ip_local_deliver;
2211         rth->rt_flags   = flags|RTCF_LOCAL;
2212         if (res.type == RTN_UNREACHABLE) {
2213                 rth->dst.input= ip_error;
2214                 rth->dst.error= -err;
2215                 rth->rt_flags   &= ~RTCF_LOCAL;
2216         }
2217         rth->rt_type    = res.type;
2218         hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2219         rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2220         err = 0;
2221         if (IS_ERR(rth))
2222                 err = PTR_ERR(rth);
2223         goto out;
2224
2225 no_route:
2226         RT_CACHE_STAT_INC(in_no_route);
2227         spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
2228         res.type = RTN_UNREACHABLE;
2229         if (err == -ESRCH)
2230                 err = -ENETUNREACH;
2231         goto local_input;
2232
2233         /*
2234          *      Do not cache martian addresses: they should be logged (RFC1812)
2235          */
2236 martian_destination:
2237         RT_CACHE_STAT_INC(in_martian_dst);
2238 #ifdef CONFIG_IP_ROUTE_VERBOSE
2239         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
2240                 printk(KERN_WARNING "martian destination %pI4 from %pI4, dev %s\n",
2241                         &daddr, &saddr, dev->name);
2242 #endif
2243
2244 e_hostunreach:
2245         err = -EHOSTUNREACH;
2246         goto out;
2247
2248 e_inval:
2249         err = -EINVAL;
2250         goto out;
2251
2252 e_nobufs:
2253         err = -ENOBUFS;
2254         goto out;
2255
2256 martian_source:
2257         err = -EINVAL;
2258 martian_source_keep_err:
2259         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2260         goto out;
2261 }
2262
2263 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2264                            u8 tos, struct net_device *dev, bool noref)
2265 {
2266         struct rtable * rth;
2267         unsigned        hash;
2268         int iif = dev->ifindex;
2269         struct net *net;
2270         int res;
2271
2272         net = dev_net(dev);
2273
2274         rcu_read_lock();
2275
2276         if (!rt_caching(net))
2277                 goto skip_cache;
2278
2279         tos &= IPTOS_RT_MASK;
2280         hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2281
2282         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2283              rth = rcu_dereference(rth->dst.rt_next)) {
2284                 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2285                      ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2286                      (rth->rt_iif ^ iif) |
2287                      rth->rt_oif |
2288                      (rth->rt_tos ^ tos)) == 0 &&
2289                     rth->rt_mark == skb->mark &&
2290                     net_eq(dev_net(rth->dst.dev), net) &&
2291                     !rt_is_expired(rth)) {
2292                         if (noref) {
2293                                 dst_use_noref(&rth->dst, jiffies);
2294                                 skb_dst_set_noref(skb, &rth->dst);
2295                         } else {
2296                                 dst_use(&rth->dst, jiffies);
2297                                 skb_dst_set(skb, &rth->dst);
2298                         }
2299                         RT_CACHE_STAT_INC(in_hit);
2300                         rcu_read_unlock();
2301                         return 0;
2302                 }
2303                 RT_CACHE_STAT_INC(in_hlist_search);
2304         }
2305
2306 skip_cache:
2307         /* Multicast recognition logic is moved from route cache to here.
2308            The problem was that too many Ethernet cards have broken/missing
2309            hardware multicast filters :-( As result the host on multicasting
2310            network acquires a lot of useless route cache entries, sort of
2311            SDR messages from all the world. Now we try to get rid of them.
2312            Really, provided software IP multicast filter is organized
2313            reasonably (at least, hashed), it does not result in a slowdown
2314            comparing with route cache reject entries.
2315            Note, that multicast routers are not affected, because
2316            route cache entry is created eventually.
2317          */
2318         if (ipv4_is_multicast(daddr)) {
2319                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2320
2321                 if (in_dev) {
2322                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2323                                                   ip_hdr(skb)->protocol);
2324                         if (our
2325 #ifdef CONFIG_IP_MROUTE
2326                                 ||
2327                             (!ipv4_is_local_multicast(daddr) &&
2328                              IN_DEV_MFORWARD(in_dev))
2329 #endif
2330                            ) {
2331                                 int res = ip_route_input_mc(skb, daddr, saddr,
2332                                                             tos, dev, our);
2333                                 rcu_read_unlock();
2334                                 return res;
2335                         }
2336                 }
2337                 rcu_read_unlock();
2338                 return -EINVAL;
2339         }
2340         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2341         rcu_read_unlock();
2342         return res;
2343 }
2344 EXPORT_SYMBOL(ip_route_input_common);
2345
2346 /* called with rcu_read_lock() */
2347 static struct rtable *__mkroute_output(const struct fib_result *res,
2348                                        const struct flowi4 *fl4,
2349                                        const struct flowi4 *oldflp4,
2350                                        struct net_device *dev_out,
2351                                        unsigned int flags)
2352 {
2353         struct fib_info *fi = res->fi;
2354         u32 tos = RT_FL_TOS(oldflp4);
2355         struct in_device *in_dev;
2356         u16 type = res->type;
2357         struct rtable *rth;
2358
2359         if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2360                 return ERR_PTR(-EINVAL);
2361
2362         if (ipv4_is_lbcast(fl4->daddr))
2363                 type = RTN_BROADCAST;
2364         else if (ipv4_is_multicast(fl4->daddr))
2365                 type = RTN_MULTICAST;
2366         else if (ipv4_is_zeronet(fl4->daddr))
2367                 return ERR_PTR(-EINVAL);
2368
2369         if (dev_out->flags & IFF_LOOPBACK)
2370                 flags |= RTCF_LOCAL;
2371
2372         in_dev = __in_dev_get_rcu(dev_out);
2373         if (!in_dev)
2374                 return ERR_PTR(-EINVAL);
2375
2376         if (type == RTN_BROADCAST) {
2377                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2378                 fi = NULL;
2379         } else if (type == RTN_MULTICAST) {
2380                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2381                 if (!ip_check_mc_rcu(in_dev, oldflp4->daddr, oldflp4->saddr,
2382                                      oldflp4->flowi4_proto))
2383                         flags &= ~RTCF_LOCAL;
2384                 /* If multicast route do not exist use
2385                  * default one, but do not gateway in this case.
2386                  * Yes, it is hack.
2387                  */
2388                 if (fi && res->prefixlen < 4)
2389                         fi = NULL;
2390         }
2391
2392         rth = rt_dst_alloc(IN_DEV_CONF_GET(in_dev, NOPOLICY),
2393                            IN_DEV_CONF_GET(in_dev, NOXFRM));
2394         if (!rth)
2395                 return ERR_PTR(-ENOBUFS);
2396
2397         rth->rt_key_dst = oldflp4->daddr;
2398         rth->rt_tos     = tos;
2399         rth->rt_key_src = oldflp4->saddr;
2400         rth->rt_oif     = oldflp4->flowi4_oif;
2401         rth->rt_mark    = oldflp4->flowi4_mark;
2402         rth->rt_dst     = fl4->daddr;
2403         rth->rt_src     = fl4->saddr;
2404         rth->rt_iif     = 0;
2405         /* get references to the devices that are to be hold by the routing
2406            cache entry */
2407         rth->dst.dev    = dev_out;
2408         dev_hold(dev_out);
2409         rth->rt_gateway = fl4->daddr;
2410         rth->rt_spec_dst= fl4->saddr;
2411
2412         rth->dst.output=ip_output;
2413         rth->rt_genid = rt_genid(dev_net(dev_out));
2414
2415         RT_CACHE_STAT_INC(out_slow_tot);
2416
2417         if (flags & RTCF_LOCAL) {
2418                 rth->dst.input = ip_local_deliver;
2419                 rth->rt_spec_dst = fl4->daddr;
2420         }
2421         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2422                 rth->rt_spec_dst = fl4->saddr;
2423                 if (flags & RTCF_LOCAL &&
2424                     !(dev_out->flags & IFF_LOOPBACK)) {
2425                         rth->dst.output = ip_mc_output;
2426                         RT_CACHE_STAT_INC(out_slow_mc);
2427                 }
2428 #ifdef CONFIG_IP_MROUTE
2429                 if (type == RTN_MULTICAST) {
2430                         if (IN_DEV_MFORWARD(in_dev) &&
2431                             !ipv4_is_local_multicast(oldflp4->daddr)) {
2432                                 rth->dst.input = ip_mr_input;
2433                                 rth->dst.output = ip_mc_output;
2434                         }
2435                 }
2436 #endif
2437         }
2438
2439         rt_set_nexthop(rth, oldflp4, res, fi, type, 0);
2440
2441         rth->rt_flags = flags;
2442         return rth;
2443 }
2444
2445 /*
2446  * Major route resolver routine.
2447  * called with rcu_read_lock();
2448  */
2449
2450 static struct rtable *ip_route_output_slow(struct net *net,
2451                                            const struct flowi4 *oldflp4)
2452 {
2453         u32 tos = RT_FL_TOS(oldflp4);
2454         struct flowi4 fl4;
2455         struct fib_result res;
2456         unsigned int flags = 0;
2457         struct net_device *dev_out = NULL;
2458         struct rtable *rth;
2459
2460         res.fi          = NULL;
2461 #ifdef CONFIG_IP_MULTIPLE_TABLES
2462         res.r           = NULL;
2463 #endif
2464
2465         fl4.flowi4_oif = oldflp4->flowi4_oif;
2466         fl4.flowi4_iif = net->loopback_dev->ifindex;
2467         fl4.flowi4_mark = oldflp4->flowi4_mark;
2468         fl4.daddr = oldflp4->daddr;
2469         fl4.saddr = oldflp4->saddr;
2470         fl4.flowi4_tos = tos & IPTOS_RT_MASK;
2471         fl4.flowi4_scope = ((tos & RTO_ONLINK) ?
2472                         RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2473
2474         rcu_read_lock();
2475         if (oldflp4->saddr) {
2476                 rth = ERR_PTR(-EINVAL);
2477                 if (ipv4_is_multicast(oldflp4->saddr) ||
2478                     ipv4_is_lbcast(oldflp4->saddr) ||
2479                     ipv4_is_zeronet(oldflp4->saddr))
2480                         goto out;
2481
2482                 /* I removed check for oif == dev_out->oif here.
2483                    It was wrong for two reasons:
2484                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2485                       is assigned to multiple interfaces.
2486                    2. Moreover, we are allowed to send packets with saddr
2487                       of another iface. --ANK
2488                  */
2489
2490                 if (oldflp4->flowi4_oif == 0 &&
2491                     (ipv4_is_multicast(oldflp4->daddr) ||
2492                      ipv4_is_lbcast(oldflp4->daddr))) {
2493                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2494                         dev_out = __ip_dev_find(net, oldflp4->saddr, false);
2495                         if (dev_out == NULL)
2496                                 goto out;
2497
2498                         /* Special hack: user can direct multicasts
2499                            and limited broadcast via necessary interface
2500                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2501                            This hack is not just for fun, it allows
2502                            vic,vat and friends to work.
2503                            They bind socket to loopback, set ttl to zero
2504                            and expect that it will work.
2505                            From the viewpoint of routing cache they are broken,
2506                            because we are not allowed to build multicast path
2507                            with loopback source addr (look, routing cache
2508                            cannot know, that ttl is zero, so that packet
2509                            will not leave this host and route is valid).
2510                            Luckily, this hack is good workaround.
2511                          */
2512
2513                         fl4.flowi4_oif = dev_out->ifindex;
2514                         goto make_route;
2515                 }
2516
2517                 if (!(oldflp4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2518                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2519                         if (!__ip_dev_find(net, oldflp4->saddr, false))
2520                                 goto out;
2521                 }
2522         }
2523
2524
2525         if (oldflp4->flowi4_oif) {
2526                 dev_out = dev_get_by_index_rcu(net, oldflp4->flowi4_oif);
2527                 rth = ERR_PTR(-ENODEV);
2528                 if (dev_out == NULL)
2529                         goto out;
2530
2531                 /* RACE: Check return value of inet_select_addr instead. */
2532                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2533                         rth = ERR_PTR(-ENETUNREACH);
2534                         goto out;
2535                 }
2536                 if (ipv4_is_local_multicast(oldflp4->daddr) ||
2537                     ipv4_is_lbcast(oldflp4->daddr)) {
2538                         if (!fl4.saddr)
2539                                 fl4.saddr = inet_select_addr(dev_out, 0,
2540                                                              RT_SCOPE_LINK);
2541                         goto make_route;
2542                 }
2543                 if (!fl4.saddr) {
2544                         if (ipv4_is_multicast(oldflp4->daddr))
2545                                 fl4.saddr = inet_select_addr(dev_out, 0,
2546                                                              fl4.flowi4_scope);
2547                         else if (!oldflp4->daddr)
2548                                 fl4.saddr = inet_select_addr(dev_out, 0,
2549                                                              RT_SCOPE_HOST);
2550                 }
2551         }
2552
2553         if (!fl4.daddr) {
2554                 fl4.daddr = fl4.saddr;
2555                 if (!fl4.daddr)
2556                         fl4.daddr = fl4.saddr = htonl(INADDR_LOOPBACK);
2557                 dev_out = net->loopback_dev;
2558                 fl4.flowi4_oif = net->loopback_dev->ifindex;
2559                 res.type = RTN_LOCAL;
2560                 flags |= RTCF_LOCAL;
2561                 goto make_route;
2562         }
2563
2564         if (fib_lookup(net, &fl4, &res)) {
2565                 res.fi = NULL;
2566                 if (oldflp4->flowi4_oif) {
2567                         /* Apparently, routing tables are wrong. Assume,
2568                            that the destination is on link.
2569
2570                            WHY? DW.
2571                            Because we are allowed to send to iface
2572                            even if it has NO routes and NO assigned
2573                            addresses. When oif is specified, routing
2574                            tables are looked up with only one purpose:
2575                            to catch if destination is gatewayed, rather than
2576                            direct. Moreover, if MSG_DONTROUTE is set,
2577                            we send packet, ignoring both routing tables
2578                            and ifaddr state. --ANK
2579
2580
2581                            We could make it even if oif is unknown,
2582                            likely IPv6, but we do not.
2583                          */
2584
2585                         if (fl4.saddr == 0)
2586                                 fl4.saddr = inet_select_addr(dev_out, 0,
2587                                                              RT_SCOPE_LINK);
2588                         res.type = RTN_UNICAST;
2589                         goto make_route;
2590                 }
2591                 rth = ERR_PTR(-ENETUNREACH);
2592                 goto out;
2593         }
2594
2595         if (res.type == RTN_LOCAL) {
2596                 if (!fl4.saddr) {
2597                         if (res.fi->fib_prefsrc)
2598                                 fl4.saddr = res.fi->fib_prefsrc;
2599                         else
2600                                 fl4.saddr = fl4.daddr;
2601                 }
2602                 dev_out = net->loopback_dev;
2603                 fl4.flowi4_oif = dev_out->ifindex;
2604                 res.fi = NULL;
2605                 flags |= RTCF_LOCAL;
2606                 goto make_route;
2607         }
2608
2609 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2610         if (res.fi->fib_nhs > 1 && fl4.flowi4_oif == 0)
2611                 fib_select_multipath(&res);
2612         else
2613 #endif
2614         if (!res.prefixlen && res.type == RTN_UNICAST && !fl4.flowi4_oif)
2615                 fib_select_default(&res);
2616
2617         if (!fl4.saddr)
2618                 fl4.saddr = FIB_RES_PREFSRC(net, res);
2619
2620         dev_out = FIB_RES_DEV(res);
2621         fl4.flowi4_oif = dev_out->ifindex;
2622
2623
2624 make_route:
2625         rth = __mkroute_output(&res, &fl4, oldflp4, dev_out, flags);
2626         if (!IS_ERR(rth)) {
2627                 unsigned int hash;
2628
2629                 hash = rt_hash(oldflp4->daddr, oldflp4->saddr, oldflp4->flowi4_oif,
2630                                rt_genid(dev_net(dev_out)));
2631                 rth = rt_intern_hash(hash, rth, NULL, oldflp4->flowi4_oif);
2632         }
2633
2634 out:
2635         rcu_read_unlock();
2636         return rth;
2637 }
2638
2639 struct rtable *__ip_route_output_key(struct net *net, const struct flowi4 *flp4)
2640 {
2641         struct rtable *rth;
2642         unsigned int hash;
2643
2644         if (!rt_caching(net))
2645                 goto slow_output;
2646
2647         hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2648
2649         rcu_read_lock_bh();
2650         for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2651                 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2652                 if (rth->rt_key_dst == flp4->daddr &&
2653                     rth->rt_key_src == flp4->saddr &&
2654                     rt_is_output_route(rth) &&
2655                     rth->rt_oif == flp4->flowi4_oif &&
2656                     rth->rt_mark == flp4->flowi4_mark &&
2657                     !((rth->rt_tos ^ flp4->flowi4_tos) &
2658                             (IPTOS_RT_MASK | RTO_ONLINK)) &&
2659                     net_eq(dev_net(rth->dst.dev), net) &&
2660                     !rt_is_expired(rth)) {
2661                         dst_use(&rth->dst, jiffies);
2662                         RT_CACHE_STAT_INC(out_hit);
2663                         rcu_read_unlock_bh();
2664                         return rth;
2665                 }
2666                 RT_CACHE_STAT_INC(out_hlist_search);
2667         }
2668         rcu_read_unlock_bh();
2669
2670 slow_output:
2671         return ip_route_output_slow(net, flp4);
2672 }
2673 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2674
2675 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2676 {
2677         return NULL;
2678 }
2679
2680 static unsigned int ipv4_blackhole_default_mtu(const struct dst_entry *dst)
2681 {
2682         return 0;
2683 }
2684
2685 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2686 {
2687 }
2688
2689 static struct dst_ops ipv4_dst_blackhole_ops = {
2690         .family                 =       AF_INET,
2691         .protocol               =       cpu_to_be16(ETH_P_IP),
2692         .destroy                =       ipv4_dst_destroy,
2693         .check                  =       ipv4_blackhole_dst_check,
2694         .default_mtu            =       ipv4_blackhole_default_mtu,
2695         .default_advmss         =       ipv4_default_advmss,
2696         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2697 };
2698
2699 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2700 {
2701         struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, 1);
2702         struct rtable *ort = (struct rtable *) dst_orig;
2703
2704         if (rt) {
2705                 struct dst_entry *new = &rt->dst;
2706
2707                 new->__use = 1;
2708                 new->input = dst_discard;
2709                 new->output = dst_discard;
2710                 dst_copy_metrics(new, &ort->dst);
2711
2712                 new->dev = ort->dst.dev;
2713                 if (new->dev)
2714                         dev_hold(new->dev);
2715
2716                 rt->rt_key_dst = ort->rt_key_dst;
2717                 rt->rt_key_src = ort->rt_key_src;
2718                 rt->rt_tos = ort->rt_tos;
2719                 rt->rt_iif = ort->rt_iif;
2720                 rt->rt_oif = ort->rt_oif;
2721                 rt->rt_mark = ort->rt_mark;
2722
2723                 rt->rt_genid = rt_genid(net);
2724                 rt->rt_flags = ort->rt_flags;
2725                 rt->rt_type = ort->rt_type;
2726                 rt->rt_dst = ort->rt_dst;
2727                 rt->rt_src = ort->rt_src;
2728                 rt->rt_iif = ort->rt_iif;
2729                 rt->rt_gateway = ort->rt_gateway;
2730                 rt->rt_spec_dst = ort->rt_spec_dst;
2731                 rt->peer = ort->peer;
2732                 if (rt->peer)
2733                         atomic_inc(&rt->peer->refcnt);
2734                 rt->fi = ort->fi;
2735                 if (rt->fi)
2736                         atomic_inc(&rt->fi->fib_clntref);
2737
2738                 dst_free(new);
2739         }
2740
2741         dst_release(dst_orig);
2742
2743         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2744 }
2745
2746 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2747                                     struct sock *sk)
2748 {
2749         struct rtable *rt = __ip_route_output_key(net, flp4);
2750
2751         if (IS_ERR(rt))
2752                 return rt;
2753
2754         if (flp4->flowi4_proto) {
2755                 if (!flp4->saddr)
2756                         flp4->saddr = rt->rt_src;
2757                 if (!flp4->daddr)
2758                         flp4->daddr = rt->rt_dst;
2759                 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2760                                                    flowi4_to_flowi(flp4),
2761                                                    sk, 0);
2762         }
2763
2764         return rt;
2765 }
2766 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2767
2768 static int rt_fill_info(struct net *net,
2769                         struct sk_buff *skb, u32 pid, u32 seq, int event,
2770                         int nowait, unsigned int flags)
2771 {
2772         struct rtable *rt = skb_rtable(skb);
2773         struct rtmsg *r;
2774         struct nlmsghdr *nlh;
2775         long expires;
2776         u32 id = 0, ts = 0, tsage = 0, error;
2777
2778         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2779         if (nlh == NULL)
2780                 return -EMSGSIZE;
2781
2782         r = nlmsg_data(nlh);
2783         r->rtm_family    = AF_INET;
2784         r->rtm_dst_len  = 32;
2785         r->rtm_src_len  = 0;
2786         r->rtm_tos      = rt->rt_tos;
2787         r->rtm_table    = RT_TABLE_MAIN;
2788         NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
2789         r->rtm_type     = rt->rt_type;
2790         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2791         r->rtm_protocol = RTPROT_UNSPEC;
2792         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2793         if (rt->rt_flags & RTCF_NOTIFY)
2794                 r->rtm_flags |= RTM_F_NOTIFY;
2795
2796         NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2797
2798         if (rt->rt_key_src) {
2799                 r->rtm_src_len = 32;
2800                 NLA_PUT_BE32(skb, RTA_SRC, rt->rt_key_src);
2801         }
2802         if (rt->dst.dev)
2803                 NLA_PUT_U32(skb, RTA_OIF, rt->dst.dev->ifindex);
2804 #ifdef CONFIG_IP_ROUTE_CLASSID
2805         if (rt->dst.tclassid)
2806                 NLA_PUT_U32(skb, RTA_FLOW, rt->dst.tclassid);
2807 #endif
2808         if (rt_is_input_route(rt))
2809                 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
2810         else if (rt->rt_src != rt->rt_key_src)
2811                 NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2812
2813         if (rt->rt_dst != rt->rt_gateway)
2814                 NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2815
2816         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2817                 goto nla_put_failure;
2818
2819         if (rt->rt_mark)
2820                 NLA_PUT_BE32(skb, RTA_MARK, rt->rt_mark);
2821
2822         error = rt->dst.error;
2823         expires = (rt->peer && rt->peer->pmtu_expires) ?
2824                 rt->peer->pmtu_expires - jiffies : 0;
2825         if (rt->peer) {
2826                 inet_peer_refcheck(rt->peer);
2827                 id = atomic_read(&rt->peer->ip_id_count) & 0xffff;
2828                 if (rt->peer->tcp_ts_stamp) {
2829                         ts = rt->peer->tcp_ts;
2830                         tsage = get_seconds() - rt->peer->tcp_ts_stamp;
2831                 }
2832         }
2833
2834         if (rt_is_input_route(rt)) {
2835 #ifdef CONFIG_IP_MROUTE
2836                 __be32 dst = rt->rt_dst;
2837
2838                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2839                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2840                         int err = ipmr_get_route(net, skb, r, nowait);
2841                         if (err <= 0) {
2842                                 if (!nowait) {
2843                                         if (err == 0)
2844                                                 return 0;
2845                                         goto nla_put_failure;
2846                                 } else {
2847                                         if (err == -EMSGSIZE)
2848                                                 goto nla_put_failure;
2849                                         error = err;
2850                                 }
2851                         }
2852                 } else
2853 #endif
2854                         NLA_PUT_U32(skb, RTA_IIF, rt->rt_iif);
2855         }
2856
2857         if (rtnl_put_cacheinfo(skb, &rt->dst, id, ts, tsage,
2858                                expires, error) < 0)
2859                 goto nla_put_failure;
2860
2861         return nlmsg_end(skb, nlh);
2862
2863 nla_put_failure:
2864         nlmsg_cancel(skb, nlh);
2865         return -EMSGSIZE;
2866 }
2867
2868 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
2869 {
2870         struct net *net = sock_net(in_skb->sk);
2871         struct rtmsg *rtm;
2872         struct nlattr *tb[RTA_MAX+1];
2873         struct rtable *rt = NULL;
2874         __be32 dst = 0;
2875         __be32 src = 0;
2876         u32 iif;
2877         int err;
2878         int mark;
2879         struct sk_buff *skb;
2880
2881         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2882         if (err < 0)
2883                 goto errout;
2884
2885         rtm = nlmsg_data(nlh);
2886
2887         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2888         if (skb == NULL) {
2889                 err = -ENOBUFS;
2890                 goto errout;
2891         }
2892
2893         /* Reserve room for dummy headers, this skb can pass
2894            through good chunk of routing engine.
2895          */
2896         skb_reset_mac_header(skb);
2897         skb_reset_network_header(skb);
2898
2899         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2900         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2901         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2902
2903         src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2904         dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2905         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2906         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2907
2908         if (iif) {
2909                 struct net_device *dev;
2910
2911                 dev = __dev_get_by_index(net, iif);
2912                 if (dev == NULL) {
2913                         err = -ENODEV;
2914                         goto errout_free;
2915                 }
2916
2917                 skb->protocol   = htons(ETH_P_IP);
2918                 skb->dev        = dev;
2919                 skb->mark       = mark;
2920                 local_bh_disable();
2921                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2922                 local_bh_enable();
2923
2924                 rt = skb_rtable(skb);
2925                 if (err == 0 && rt->dst.error)
2926                         err = -rt->dst.error;
2927         } else {
2928                 struct flowi4 fl4 = {
2929                         .daddr = dst,
2930                         .saddr = src,
2931                         .flowi4_tos = rtm->rtm_tos,
2932                         .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2933                         .flowi4_mark = mark,
2934                 };
2935                 rt = ip_route_output_key(net, &fl4);
2936
2937                 err = 0;
2938                 if (IS_ERR(rt))
2939                         err = PTR_ERR(rt);
2940         }
2941
2942         if (err)
2943                 goto errout_free;
2944
2945         skb_dst_set(skb, &rt->dst);
2946         if (rtm->rtm_flags & RTM_F_NOTIFY)
2947                 rt->rt_flags |= RTCF_NOTIFY;
2948
2949         err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2950                            RTM_NEWROUTE, 0, 0);
2951         if (err <= 0)
2952                 goto errout_free;
2953
2954         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2955 errout:
2956         return err;
2957
2958 errout_free:
2959         kfree_skb(skb);
2960         goto errout;
2961 }
2962
2963 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
2964 {
2965         struct rtable *rt;
2966         int h, s_h;
2967         int idx, s_idx;
2968         struct net *net;
2969
2970         net = sock_net(skb->sk);
2971
2972         s_h = cb->args[0];
2973         if (s_h < 0)
2974                 s_h = 0;
2975         s_idx = idx = cb->args[1];
2976         for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
2977                 if (!rt_hash_table[h].chain)
2978                         continue;
2979                 rcu_read_lock_bh();
2980                 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
2981                      rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
2982                         if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
2983                                 continue;
2984                         if (rt_is_expired(rt))
2985                                 continue;
2986                         skb_dst_set_noref(skb, &rt->dst);
2987                         if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
2988                                          cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2989                                          1, NLM_F_MULTI) <= 0) {
2990                                 skb_dst_drop(skb);
2991                                 rcu_read_unlock_bh();
2992                                 goto done;
2993                         }
2994                         skb_dst_drop(skb);
2995                 }
2996                 rcu_read_unlock_bh();
2997         }
2998
2999 done:
3000         cb->args[0] = h;
3001         cb->args[1] = idx;
3002         return skb->len;
3003 }
3004
3005 void ip_rt_multicast_event(struct in_device *in_dev)
3006 {
3007         rt_cache_flush(dev_net(in_dev->dev), 0);
3008 }
3009
3010 #ifdef CONFIG_SYSCTL
3011 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
3012                                         void __user *buffer,
3013                                         size_t *lenp, loff_t *ppos)
3014 {
3015         if (write) {
3016                 int flush_delay;
3017                 ctl_table ctl;
3018                 struct net *net;
3019
3020                 memcpy(&ctl, __ctl, sizeof(ctl));
3021                 ctl.data = &flush_delay;
3022                 proc_dointvec(&ctl, write, buffer, lenp, ppos);
3023
3024                 net = (struct net *)__ctl->extra1;
3025                 rt_cache_flush(net, flush_delay);
3026                 return 0;
3027         }
3028
3029         return -EINVAL;
3030 }
3031
3032 static ctl_table ipv4_route_table[] = {
3033         {
3034                 .procname       = "gc_thresh",
3035                 .data           = &ipv4_dst_ops.gc_thresh,
3036                 .maxlen         = sizeof(int),
3037                 .mode           = 0644,
3038                 .proc_handler   = proc_dointvec,
3039         },
3040         {
3041                 .procname       = "max_size",
3042                 .data           = &ip_rt_max_size,
3043                 .maxlen         = sizeof(int),
3044                 .mode           = 0644,
3045                 .proc_handler   = proc_dointvec,
3046         },
3047         {
3048                 /*  Deprecated. Use gc_min_interval_ms */
3049
3050                 .procname       = "gc_min_interval",
3051                 .data           = &ip_rt_gc_min_interval,
3052                 .maxlen         = sizeof(int),
3053                 .mode           = 0644,
3054                 .proc_handler   = proc_dointvec_jiffies,
3055         },
3056         {
3057                 .procname       = "gc_min_interval_ms",
3058                 .data           = &ip_rt_gc_min_interval,
3059                 .maxlen         = sizeof(int),
3060                 .mode           = 0644,
3061                 .proc_handler   = proc_dointvec_ms_jiffies,
3062         },
3063         {
3064                 .procname       = "gc_timeout",
3065                 .data           = &ip_rt_gc_timeout,
3066                 .maxlen         = sizeof(int),
3067                 .mode           = 0644,
3068                 .proc_handler   = proc_dointvec_jiffies,
3069         },
3070         {
3071                 .procname       = "gc_interval",
3072                 .data           = &ip_rt_gc_interval,
3073                 .maxlen         = sizeof(int),
3074                 .mode           = 0644,
3075                 .proc_handler   = proc_dointvec_jiffies,
3076         },
3077         {
3078                 .procname       = "redirect_load",
3079                 .data           = &ip_rt_redirect_load,
3080                 .maxlen         = sizeof(int),
3081                 .mode           = 0644,
3082                 .proc_handler   = proc_dointvec,
3083         },
3084         {
3085                 .procname       = "redirect_number",
3086                 .data           = &ip_rt_redirect_number,
3087                 .maxlen         = sizeof(int),
3088                 .mode           = 0644,
3089                 .proc_handler   = proc_dointvec,
3090         },
3091         {
3092                 .procname       = "redirect_silence",
3093                 .data           = &ip_rt_redirect_silence,
3094                 .maxlen         = sizeof(int),
3095                 .mode           = 0644,
3096                 .proc_handler   = proc_dointvec,
3097         },
3098         {
3099                 .procname       = "error_cost",
3100                 .data           = &ip_rt_error_cost,
3101                 .maxlen         = sizeof(int),
3102                 .mode           = 0644,
3103                 .proc_handler   = proc_dointvec,
3104         },
3105         {
3106                 .procname       = "error_burst",
3107                 .data           = &ip_rt_error_burst,
3108                 .maxlen         = sizeof(int),
3109                 .mode           = 0644,
3110                 .proc_handler   = proc_dointvec,
3111         },
3112         {
3113                 .procname       = "gc_elasticity",
3114                 .data           = &ip_rt_gc_elasticity,
3115                 .maxlen         = sizeof(int),
3116                 .mode           = 0644,
3117                 .proc_handler   = proc_dointvec,
3118         },
3119         {
3120                 .procname       = "mtu_expires",
3121                 .data           = &ip_rt_mtu_expires,
3122                 .maxlen         = sizeof(int),
3123                 .mode           = 0644,
3124                 .proc_handler   = proc_dointvec_jiffies,
3125         },
3126         {
3127                 .procname       = "min_pmtu",
3128                 .data           = &ip_rt_min_pmtu,
3129                 .maxlen         = sizeof(int),
3130                 .mode           = 0644,
3131                 .proc_handler   = proc_dointvec,
3132         },
3133         {
3134                 .procname       = "min_adv_mss",
3135                 .data           = &ip_rt_min_advmss,
3136                 .maxlen         = sizeof(int),
3137                 .mode           = 0644,
3138                 .proc_handler   = proc_dointvec,
3139         },
3140         { }
3141 };
3142
3143 static struct ctl_table empty[1];
3144
3145 static struct ctl_table ipv4_skeleton[] =
3146 {
3147         { .procname = "route",
3148           .mode = 0555, .child = ipv4_route_table},
3149         { .procname = "neigh",
3150           .mode = 0555, .child = empty},
3151         { }
3152 };
3153
3154 static __net_initdata struct ctl_path ipv4_path[] = {
3155         { .procname = "net", },
3156         { .procname = "ipv4", },
3157         { },
3158 };
3159
3160 static struct ctl_table ipv4_route_flush_table[] = {
3161         {
3162                 .procname       = "flush",
3163                 .maxlen         = sizeof(int),
3164                 .mode           = 0200,
3165                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3166         },
3167         { },
3168 };
3169
3170 static __net_initdata struct ctl_path ipv4_route_path[] = {
3171         { .procname = "net", },
3172         { .procname = "ipv4", },
3173         { .procname = "route", },
3174         { },
3175 };
3176
3177 static __net_init int sysctl_route_net_init(struct net *net)
3178 {
3179         struct ctl_table *tbl;
3180
3181         tbl = ipv4_route_flush_table;
3182         if (!net_eq(net, &init_net)) {
3183                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3184                 if (tbl == NULL)
3185                         goto err_dup;
3186         }
3187         tbl[0].extra1 = net;
3188
3189         net->ipv4.route_hdr =
3190                 register_net_sysctl_table(net, ipv4_route_path, tbl);
3191         if (net->ipv4.route_hdr == NULL)
3192                 goto err_reg;
3193         return 0;
3194
3195 err_reg:
3196         if (tbl != ipv4_route_flush_table)
3197                 kfree(tbl);
3198 err_dup:
3199         return -ENOMEM;
3200 }
3201
3202 static __net_exit void sysctl_route_net_exit(struct net *net)
3203 {
3204         struct ctl_table *tbl;
3205
3206         tbl = net->ipv4.route_hdr->ctl_table_arg;
3207         unregister_net_sysctl_table(net->ipv4.route_hdr);
3208         BUG_ON(tbl == ipv4_route_flush_table);
3209         kfree(tbl);
3210 }
3211
3212 static __net_initdata struct pernet_operations sysctl_route_ops = {
3213         .init = sysctl_route_net_init,
3214         .exit = sysctl_route_net_exit,
3215 };
3216 #endif
3217
3218 static __net_init int rt_genid_init(struct net *net)
3219 {
3220         get_random_bytes(&net->ipv4.rt_genid,
3221                          sizeof(net->ipv4.rt_genid));
3222         get_random_bytes(&net->ipv4.dev_addr_genid,
3223                          sizeof(net->ipv4.dev_addr_genid));
3224         return 0;
3225 }
3226
3227 static __net_initdata struct pernet_operations rt_genid_ops = {
3228         .init = rt_genid_init,
3229 };
3230
3231
3232 #ifdef CONFIG_IP_ROUTE_CLASSID
3233 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3234 #endif /* CONFIG_IP_ROUTE_CLASSID */
3235
3236 static __initdata unsigned long rhash_entries;
3237 static int __init set_rhash_entries(char *str)
3238 {
3239         if (!str)
3240                 return 0;
3241         rhash_entries = simple_strtoul(str, &str, 0);
3242         return 1;
3243 }
3244 __setup("rhash_entries=", set_rhash_entries);
3245
3246 int __init ip_rt_init(void)
3247 {
3248         int rc = 0;
3249
3250 #ifdef CONFIG_IP_ROUTE_CLASSID
3251         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3252         if (!ip_rt_acct)
3253                 panic("IP: failed to allocate ip_rt_acct\n");
3254 #endif
3255
3256         ipv4_dst_ops.kmem_cachep =
3257                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3258                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3259
3260         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3261
3262         if (dst_entries_init(&ipv4_dst_ops) < 0)
3263                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3264
3265         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3266                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3267
3268         rt_hash_table = (struct rt_hash_bucket *)
3269                 alloc_large_system_hash("IP route cache",
3270                                         sizeof(struct rt_hash_bucket),
3271                                         rhash_entries,
3272                                         (totalram_pages >= 128 * 1024) ?
3273                                         15 : 17,
3274                                         0,
3275                                         &rt_hash_log,
3276                                         &rt_hash_mask,
3277                                         rhash_entries ? 0 : 512 * 1024);
3278         memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3279         rt_hash_lock_init();
3280
3281         ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3282         ip_rt_max_size = (rt_hash_mask + 1) * 16;
3283
3284         devinet_init();
3285         ip_fib_init();
3286
3287         if (ip_rt_proc_init())
3288                 printk(KERN_ERR "Unable to create route proc files\n");
3289 #ifdef CONFIG_XFRM
3290         xfrm_init();
3291         xfrm4_init(ip_rt_max_size);
3292 #endif
3293         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);
3294
3295 #ifdef CONFIG_SYSCTL
3296         register_pernet_subsys(&sysctl_route_ops);
3297 #endif
3298         register_pernet_subsys(&rt_genid_ops);
3299         return rc;
3300 }
3301
3302 #ifdef CONFIG_SYSCTL
3303 /*
3304  * We really need to sanitize the damn ipv4 init order, then all
3305  * this nonsense will go away.
3306  */
3307 void __init ip_static_sysctl_init(void)
3308 {
3309         register_sysctl_paths(ipv4_path, ipv4_skeleton);
3310 }
3311 #endif