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 #define pr_fmt(fmt) "IPv4: " fmt
  66
  67 #include <linux/module.h>
  68 #include <asm/uaccess.h>
  69 #include <linux/bitops.h>
  70 #include <linux/types.h>
  71 #include <linux/kernel.h>
  72 #include <linux/mm.h>
  73 #include <linux/bootmem.h>
  74 #include <linux/string.h>
  75 #include <linux/socket.h>
  76 #include <linux/sockios.h>
  77 #include <linux/errno.h>
  78 #include <linux/in.h>
  79 #include <linux/inet.h>
  80 #include <linux/netdevice.h>
  81 #include <linux/proc_fs.h>
  82 #include <linux/init.h>
  83 #include <linux/workqueue.h>
  84 #include <linux/skbuff.h>
  85 #include <linux/inetdevice.h>
  86 #include <linux/igmp.h>
  87 #include <linux/pkt_sched.h>
  88 #include <linux/mroute.h>
  89 #include <linux/netfilter_ipv4.h>
  90 #include <linux/random.h>
  91 #include <linux/jhash.h>
  92 #include <linux/rcupdate.h>
  93 #include <linux/times.h>
  94 #include <linux/slab.h>
  95 #include <linux/prefetch.h>
  96 #include <net/dst.h>
  97 #include <net/net_namespace.h>
  98 #include <net/protocol.h>
  99 #include <net/ip.h>
 100 #include <net/route.h>
 101 #include <net/inetpeer.h>
 102 #include <net/sock.h>
 103 #include <net/ip_fib.h>
 104 #include <net/arp.h>
 105 #include <net/tcp.h>
 106 #include <net/icmp.h>
 107 #include <net/xfrm.h>
 108 #include <net/netevent.h>
 109 #include <net/rtnetlink.h>
 110 #ifdef CONFIG_SYSCTL
 111 #include <linux/sysctl.h>
 112 #include <linux/kmemleak.h>
 113 #endif
 114 #include <net/secure_seq.h>
 115
 116 #define RT_FL_TOS(oldflp4) \
 117         ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
 118
 119 #define IP_MAX_MTU      0xFFF0
 120
 121 #define RT_GC_TIMEOUT (300*HZ)
 122
 123 static int ip_rt_max_size;
 124 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 125 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
 126 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
 127 static int ip_rt_redirect_number __read_mostly  = 9;
 128 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 129 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 130 static int ip_rt_error_cost __read_mostly       = HZ;
 131 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 132 static int ip_rt_gc_elasticity __read_mostly    = 8;
 133 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
 134 static int ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
 135 static int ip_rt_min_advmss __read_mostly       = 256;
 136 static int rt_chain_length_max __read_mostly    = 20;
 137
 138 static struct delayed_work expires_work;
 139 static unsigned long expires_ljiffies;
 140
 141 /*
 142  *      Interface to generic destination cache.
 143  */
 144
 145 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 146 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 147 static unsigned int      ipv4_mtu(const struct dst_entry *dst);
 148 static void              ipv4_dst_destroy(struct dst_entry *dst);
 149 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
 150 static void              ipv4_link_failure(struct sk_buff *skb);
 151 static void              ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
 152 static void              ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb);
 153 static int rt_garbage_collect(struct dst_ops *ops);
 154
 155 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 156                             int how)
 157 {
 158 }
 159
 160 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 161 {
 162         WARN_ON(1);
 163         return NULL;
 164 }
 165
 166 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 167                                            struct sk_buff *skb,
 168                                            const void *daddr);
 169
 170 static struct dst_ops ipv4_dst_ops = {
 171         .family =               AF_INET,
 172         .protocol =             cpu_to_be16(ETH_P_IP),
 173         .gc =                   rt_garbage_collect,
 174         .check =                ipv4_dst_check,
 175         .default_advmss =       ipv4_default_advmss,
 176         .mtu =                  ipv4_mtu,
 177         .cow_metrics =          ipv4_cow_metrics,
 178         .destroy =              ipv4_dst_destroy,
 179         .ifdown =               ipv4_dst_ifdown,
 180         .negative_advice =      ipv4_negative_advice,
 181         .link_failure =         ipv4_link_failure,
 182         .update_pmtu =          ip_rt_update_pmtu,
 183         .redirect =             ip_do_redirect,
 184         .local_out =            __ip_local_out,
 185         .neigh_lookup =         ipv4_neigh_lookup,
 186 };
 187
 188 #define ECN_OR_COST(class)      TC_PRIO_##class
 189
 190 const __u8 ip_tos2prio[16] = {
 191         TC_PRIO_BESTEFFORT,
 192         ECN_OR_COST(BESTEFFORT),
 193         TC_PRIO_BESTEFFORT,
 194         ECN_OR_COST(BESTEFFORT),
 195         TC_PRIO_BULK,
 196         ECN_OR_COST(BULK),
 197         TC_PRIO_BULK,
 198         ECN_OR_COST(BULK),
 199         TC_PRIO_INTERACTIVE,
 200         ECN_OR_COST(INTERACTIVE),
 201         TC_PRIO_INTERACTIVE,
 202         ECN_OR_COST(INTERACTIVE),
 203         TC_PRIO_INTERACTIVE_BULK,
 204         ECN_OR_COST(INTERACTIVE_BULK),
 205         TC_PRIO_INTERACTIVE_BULK,
 206         ECN_OR_COST(INTERACTIVE_BULK)
 207 };
 208 EXPORT_SYMBOL(ip_tos2prio);
 209
 210 /*
 211  * Route cache.
 212  */
 213
 214 /* The locking scheme is rather straight forward:
 215  *
 216  * 1) Read-Copy Update protects the buckets of the central route hash.
 217  * 2) Only writers remove entries, and they hold the lock
 218  *    as they look at rtable reference counts.
 219  * 3) Only readers acquire references to rtable entries,
 220  *    they do so with atomic increments and with the
 221  *    lock held.
 222  */
 223
 224 struct rt_hash_bucket {
 225         struct rtable __rcu     *chain;
 226 };
 227
 228 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
 229         defined(CONFIG_PROVE_LOCKING)
 230 /*
 231  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
 232  * The size of this table is a power of two and depends on the number of CPUS.
 233  * (on lockdep we have a quite big spinlock_t, so keep the size down there)
 234  */
 235 #ifdef CONFIG_LOCKDEP
 236 # define RT_HASH_LOCK_SZ        256
 237 #else
 238 # if NR_CPUS >= 32
 239 #  define RT_HASH_LOCK_SZ       4096
 240 # elif NR_CPUS >= 16
 241 #  define RT_HASH_LOCK_SZ       2048
 242 # elif NR_CPUS >= 8
 243 #  define RT_HASH_LOCK_SZ       1024
 244 # elif NR_CPUS >= 4
 245 #  define RT_HASH_LOCK_SZ       512
 246 # else
 247 #  define RT_HASH_LOCK_SZ       256
 248 # endif
 249 #endif
 250
 251 static spinlock_t       *rt_hash_locks;
 252 # define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
 253
 254 static __init void rt_hash_lock_init(void)
 255 {
 256         int i;
 257
 258         rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
 259                         GFP_KERNEL);
 260         if (!rt_hash_locks)
 261                 panic("IP: failed to allocate rt_hash_locks\n");
 262
 263         for (i = 0; i < RT_HASH_LOCK_SZ; i++)
 264                 spin_lock_init(&rt_hash_locks[i]);
 265 }
 266 #else
 267 # define rt_hash_lock_addr(slot) NULL
 268
 269 static inline void rt_hash_lock_init(void)
 270 {
 271 }
 272 #endif
 273
 274 static struct rt_hash_bucket    *rt_hash_table __read_mostly;
 275 static unsigned int             rt_hash_mask __read_mostly;
 276 static unsigned int             rt_hash_log  __read_mostly;
 277
 278 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 279 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
 280
 281 static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx,
 282                                    int genid)
 283 {
 284         return jhash_3words((__force u32)daddr, (__force u32)saddr,
 285                             idx, genid)
 286                 & rt_hash_mask;
 287 }
 288
 289 static inline int rt_genid(struct net *net)
 290 {
 291         return atomic_read(&net->ipv4.rt_genid);
 292 }
 293
 294 #ifdef CONFIG_PROC_FS
 295 struct rt_cache_iter_state {
 296         struct seq_net_private p;
 297         int bucket;
 298         int genid;
 299 };
 300
 301 static struct rtable *rt_cache_get_first(struct seq_file *seq)
 302 {
 303         struct rt_cache_iter_state *st = seq->private;
 304         struct rtable *r = NULL;
 305
 306         for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
 307                 if (!rcu_access_pointer(rt_hash_table[st->bucket].chain))
 308                         continue;
 309                 rcu_read_lock_bh();
 310                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 311                 while (r) {
 312                         if (dev_net(r->dst.dev) == seq_file_net(seq) &&
 313                             r->rt_genid == st->genid)
 314                                 return r;
 315                         r = rcu_dereference_bh(r->dst.rt_next);
 316                 }
 317                 rcu_read_unlock_bh();
 318         }
 319         return r;
 320 }
 321
 322 static struct rtable *__rt_cache_get_next(struct seq_file *seq,
 323                                           struct rtable *r)
 324 {
 325         struct rt_cache_iter_state *st = seq->private;
 326
 327         r = rcu_dereference_bh(r->dst.rt_next);
 328         while (!r) {
 329                 rcu_read_unlock_bh();
 330                 do {
 331                         if (--st->bucket < 0)
 332                                 return NULL;
 333                 } while (!rcu_access_pointer(rt_hash_table[st->bucket].chain));
 334                 rcu_read_lock_bh();
 335                 r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 336         }
 337         return r;
 338 }
 339
 340 static struct rtable *rt_cache_get_next(struct seq_file *seq,
 341                                         struct rtable *r)
 342 {
 343         struct rt_cache_iter_state *st = seq->private;
 344         while ((r = __rt_cache_get_next(seq, r)) != NULL) {
 345                 if (dev_net(r->dst.dev) != seq_file_net(seq))
 346                         continue;
 347                 if (r->rt_genid == st->genid)
 348                         break;
 349         }
 350         return r;
 351 }
 352
 353 static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
 354 {
 355         struct rtable *r = rt_cache_get_first(seq);
 356
 357         if (r)
 358                 while (pos && (r = rt_cache_get_next(seq, r)))
 359                         --pos;
 360         return pos ? NULL : r;
 361 }
 362
 363 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 364 {
 365         struct rt_cache_iter_state *st = seq->private;
 366         if (*pos)
 367                 return rt_cache_get_idx(seq, *pos - 1);
 368         st->genid = rt_genid(seq_file_net(seq));
 369         return SEQ_START_TOKEN;
 370 }
 371
 372 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 373 {
 374         struct rtable *r;
 375
 376         if (v == SEQ_START_TOKEN)
 377                 r = rt_cache_get_first(seq);
 378         else
 379                 r = rt_cache_get_next(seq, v);
 380         ++*pos;
 381         return r;
 382 }
 383
 384 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 385 {
 386         if (v && v != SEQ_START_TOKEN)
 387                 rcu_read_unlock_bh();
 388 }
 389
 390 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 391 {
 392         if (v == SEQ_START_TOKEN)
 393                 seq_printf(seq, "%-127s\n",
 394                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 395                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 396                            "HHUptod\tSpecDst");
 397         else {
 398                 struct rtable *r = v;
 399                 int len;
 400
 401                 seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
 402                            "%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
 403                            r->dst.dev ? r->dst.dev->name : "*",
 404                            (__force u32)r->rt_dst,
 405                            (__force u32)r->rt_gateway,
 406                            r->rt_flags, atomic_read(&r->dst.__refcnt),
 407                            r->dst.__use, 0, (__force u32)r->rt_src,
 408                            dst_metric_advmss(&r->dst) + 40,
 409                            dst_metric(&r->dst, RTAX_WINDOW), 0,
 410                            r->rt_key_tos,
 411                            -1, 0, 0, &len);
 412
 413                 seq_printf(seq, "%*s\n", 127 - len, "");
 414         }
 415         return 0;
 416 }
 417
 418 static const struct seq_operations rt_cache_seq_ops = {
 419         .start  = rt_cache_seq_start,
 420         .next   = rt_cache_seq_next,
 421         .stop   = rt_cache_seq_stop,
 422         .show   = rt_cache_seq_show,
 423 };
 424
 425 static int rt_cache_seq_open(struct inode *inode, struct file *file)
 426 {
 427         return seq_open_net(inode, file, &rt_cache_seq_ops,
 428                         sizeof(struct rt_cache_iter_state));
 429 }
 430
 431 static const struct file_operations rt_cache_seq_fops = {
 432         .owner   = THIS_MODULE,
 433         .open    = rt_cache_seq_open,
 434         .read    = seq_read,
 435         .llseek  = seq_lseek,
 436         .release = seq_release_net,
 437 };
 438
 439
 440 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 441 {
 442         int cpu;
 443
 444         if (*pos == 0)
 445                 return SEQ_START_TOKEN;
 446
 447         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 448                 if (!cpu_possible(cpu))
 449                         continue;
 450                 *pos = cpu+1;
 451                 return &per_cpu(rt_cache_stat, cpu);
 452         }
 453         return NULL;
 454 }
 455
 456 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 457 {
 458         int cpu;
 459
 460         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 461                 if (!cpu_possible(cpu))
 462                         continue;
 463                 *pos = cpu+1;
 464                 return &per_cpu(rt_cache_stat, cpu);
 465         }
 466         return NULL;
 467
 468 }
 469
 470 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 471 {
 472
 473 }
 474
 475 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 476 {
 477         struct rt_cache_stat *st = v;
 478
 479         if (v == SEQ_START_TOKEN) {
 480                 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");
 481                 return 0;
 482         }
 483
 484         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 485                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
 486                    dst_entries_get_slow(&ipv4_dst_ops),
 487                    st->in_hit,
 488                    st->in_slow_tot,
 489                    st->in_slow_mc,
 490                    st->in_no_route,
 491                    st->in_brd,
 492                    st->in_martian_dst,
 493                    st->in_martian_src,
 494
 495                    st->out_hit,
 496                    st->out_slow_tot,
 497                    st->out_slow_mc,
 498
 499                    st->gc_total,
 500                    st->gc_ignored,
 501                    st->gc_goal_miss,
 502                    st->gc_dst_overflow,
 503                    st->in_hlist_search,
 504                    st->out_hlist_search
 505                 );
 506         return 0;
 507 }
 508
 509 static const struct seq_operations rt_cpu_seq_ops = {
 510         .start  = rt_cpu_seq_start,
 511         .next   = rt_cpu_seq_next,
 512         .stop   = rt_cpu_seq_stop,
 513         .show   = rt_cpu_seq_show,
 514 };
 515
 516
 517 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 518 {
 519         return seq_open(file, &rt_cpu_seq_ops);
 520 }
 521
 522 static const struct file_operations rt_cpu_seq_fops = {
 523         .owner   = THIS_MODULE,
 524         .open    = rt_cpu_seq_open,
 525         .read    = seq_read,
 526         .llseek  = seq_lseek,
 527         .release = seq_release,
 528 };
 529
 530 #ifdef CONFIG_IP_ROUTE_CLASSID
 531 static int rt_acct_proc_show(struct seq_file *m, void *v)
 532 {
 533         struct ip_rt_acct *dst, *src;
 534         unsigned int i, j;
 535
 536         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 537         if (!dst)
 538                 return -ENOMEM;
 539
 540         for_each_possible_cpu(i) {
 541                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 542                 for (j = 0; j < 256; j++) {
 543                         dst[j].o_bytes   += src[j].o_bytes;
 544                         dst[j].o_packets += src[j].o_packets;
 545                         dst[j].i_bytes   += src[j].i_bytes;
 546                         dst[j].i_packets += src[j].i_packets;
 547                 }
 548         }
 549
 550         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 551         kfree(dst);
 552         return 0;
 553 }
 554
 555 static int rt_acct_proc_open(struct inode *inode, struct file *file)
 556 {
 557         return single_open(file, rt_acct_proc_show, NULL);
 558 }
 559
 560 static const struct file_operations rt_acct_proc_fops = {
 561         .owner          = THIS_MODULE,
 562         .open           = rt_acct_proc_open,
 563         .read           = seq_read,
 564         .llseek         = seq_lseek,
 565         .release        = single_release,
 566 };
 567 #endif
 568
 569 static int __net_init ip_rt_do_proc_init(struct net *net)
 570 {
 571         struct proc_dir_entry *pde;
 572
 573         pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
 574                         &rt_cache_seq_fops);
 575         if (!pde)
 576                 goto err1;
 577
 578         pde = proc_create("rt_cache", S_IRUGO,
 579                           net->proc_net_stat, &rt_cpu_seq_fops);
 580         if (!pde)
 581                 goto err2;
 582
 583 #ifdef CONFIG_IP_ROUTE_CLASSID
 584         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
 585         if (!pde)
 586                 goto err3;
 587 #endif
 588         return 0;
 589
 590 #ifdef CONFIG_IP_ROUTE_CLASSID
 591 err3:
 592         remove_proc_entry("rt_cache", net->proc_net_stat);
 593 #endif
 594 err2:
 595         remove_proc_entry("rt_cache", net->proc_net);
 596 err1:
 597         return -ENOMEM;
 598 }
 599
 600 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 601 {
 602         remove_proc_entry("rt_cache", net->proc_net_stat);
 603         remove_proc_entry("rt_cache", net->proc_net);
 604 #ifdef CONFIG_IP_ROUTE_CLASSID
 605         remove_proc_entry("rt_acct", net->proc_net);
 606 #endif
 607 }
 608
 609 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 610         .init = ip_rt_do_proc_init,
 611         .exit = ip_rt_do_proc_exit,
 612 };
 613
 614 static int __init ip_rt_proc_init(void)
 615 {
 616         return register_pernet_subsys(&ip_rt_proc_ops);
 617 }
 618
 619 #else
 620 static inline int ip_rt_proc_init(void)
 621 {
 622         return 0;
 623 }
 624 #endif /* CONFIG_PROC_FS */
 625
 626 static inline void rt_free(struct rtable *rt)
 627 {
 628         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 629 }
 630
 631 static inline void rt_drop(struct rtable *rt)
 632 {
 633         ip_rt_put(rt);
 634         call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
 635 }
 636
 637 static inline int rt_fast_clean(struct rtable *rth)
 638 {
 639         /* Kill broadcast/multicast entries very aggresively, if they
 640            collide in hash table with more useful entries */
 641         return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
 642                 rt_is_input_route(rth) && rth->dst.rt_next;
 643 }
 644
 645 static inline int rt_valuable(struct rtable *rth)
 646 {
 647         return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
 648                 rth->dst.expires;
 649 }
 650
 651 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
 652 {
 653         unsigned long age;
 654         int ret = 0;
 655
 656         if (atomic_read(&rth->dst.__refcnt))
 657                 goto out;
 658
 659         age = jiffies - rth->dst.lastuse;
 660         if ((age <= tmo1 && !rt_fast_clean(rth)) ||
 661             (age <= tmo2 && rt_valuable(rth)))
 662                 goto out;
 663         ret = 1;
 664 out:    return ret;
 665 }
 666
 667 /* Bits of score are:
 668  * 31: very valuable
 669  * 30: not quite useless
 670  * 29..0: usage counter
 671  */
 672 static inline u32 rt_score(struct rtable *rt)
 673 {
 674         u32 score = jiffies - rt->dst.lastuse;
 675
 676         score = ~score & ~(3<<30);
 677
 678         if (rt_valuable(rt))
 679                 score |= (1<<31);
 680
 681         if (rt_is_output_route(rt) ||
 682             !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
 683                 score |= (1<<30);
 684
 685         return score;
 686 }
 687
 688 static inline bool rt_caching(const struct net *net)
 689 {
 690         return net->ipv4.current_rt_cache_rebuild_count <=
 691                 net->ipv4.sysctl_rt_cache_rebuild_count;
 692 }
 693
 694 static inline bool compare_hash_inputs(const struct rtable *rt1,
 695                                        const struct rtable *rt2)
 696 {
 697         return ((((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
 698                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
 699                 (rt1->rt_route_iif ^ rt2->rt_route_iif)) == 0);
 700 }
 701
 702 static inline int compare_keys(struct rtable *rt1, struct rtable *rt2)
 703 {
 704         return (((__force u32)rt1->rt_key_dst ^ (__force u32)rt2->rt_key_dst) |
 705                 ((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) |
 706                 (rt1->rt_mark ^ rt2->rt_mark) |
 707                 (rt1->rt_key_tos ^ rt2->rt_key_tos) |
 708                 (rt1->rt_route_iif ^ rt2->rt_route_iif) |
 709                 (rt1->rt_oif ^ rt2->rt_oif)) == 0;
 710 }
 711
 712 static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
 713 {
 714         return net_eq(dev_net(rt1->dst.dev), dev_net(rt2->dst.dev));
 715 }
 716
 717 static inline int rt_is_expired(struct rtable *rth)
 718 {
 719         return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
 720 }
 721
 722 /*
 723  * Perform a full scan of hash table and free all entries.
 724  * Can be called by a softirq or a process.
 725  * In the later case, we want to be reschedule if necessary
 726  */
 727 static void rt_do_flush(struct net *net, int process_context)
 728 {
 729         unsigned int i;
 730         struct rtable *rth, *next;
 731
 732         for (i = 0; i <= rt_hash_mask; i++) {
 733                 struct rtable __rcu **pprev;
 734                 struct rtable *list;
 735
 736                 if (process_context && need_resched())
 737                         cond_resched();
 738                 rth = rcu_access_pointer(rt_hash_table[i].chain);
 739                 if (!rth)
 740                         continue;
 741
 742                 spin_lock_bh(rt_hash_lock_addr(i));
 743
 744                 list = NULL;
 745                 pprev = &rt_hash_table[i].chain;
 746                 rth = rcu_dereference_protected(*pprev,
 747                         lockdep_is_held(rt_hash_lock_addr(i)));
 748
 749                 while (rth) {
 750                         next = rcu_dereference_protected(rth->dst.rt_next,
 751                                 lockdep_is_held(rt_hash_lock_addr(i)));
 752
 753                         if (!net ||
 754                             net_eq(dev_net(rth->dst.dev), net)) {
 755                                 rcu_assign_pointer(*pprev, next);
 756                                 rcu_assign_pointer(rth->dst.rt_next, list);
 757                                 list = rth;
 758                         } else {
 759                                 pprev = &rth->dst.rt_next;
 760                         }
 761                         rth = next;
 762                 }
 763
 764                 spin_unlock_bh(rt_hash_lock_addr(i));
 765
 766                 for (; list; list = next) {
 767                         next = rcu_dereference_protected(list->dst.rt_next, 1);
 768                         rt_free(list);
 769                 }
 770         }
 771 }
 772
 773 /*
 774  * While freeing expired entries, we compute average chain length
 775  * and standard deviation, using fixed-point arithmetic.
 776  * This to have an estimation of rt_chain_length_max
 777  *  rt_chain_length_max = max(elasticity, AVG + 4*SD)
 778  * We use 3 bits for frational part, and 29 (or 61) for magnitude.
 779  */
 780
 781 #define FRACT_BITS 3
 782 #define ONE (1UL << FRACT_BITS)
 783
 784 /*
 785  * Given a hash chain and an item in this hash chain,
 786  * find if a previous entry has the same hash_inputs
 787  * (but differs on tos, mark or oif)
 788  * Returns 0 if an alias is found.
 789  * Returns ONE if rth has no alias before itself.
 790  */
 791 static int has_noalias(const struct rtable *head, const struct rtable *rth)
 792 {
 793         const struct rtable *aux = head;
 794
 795         while (aux != rth) {
 796                 if (compare_hash_inputs(aux, rth))
 797                         return 0;
 798                 aux = rcu_dereference_protected(aux->dst.rt_next, 1);
 799         }
 800         return ONE;
 801 }
 802
 803 static void rt_check_expire(void)
 804 {
 805         static unsigned int rover;
 806         unsigned int i = rover, goal;
 807         struct rtable *rth;
 808         struct rtable __rcu **rthp;
 809         unsigned long samples = 0;
 810         unsigned long sum = 0, sum2 = 0;
 811         unsigned long delta;
 812         u64 mult;
 813
 814         delta = jiffies - expires_ljiffies;
 815         expires_ljiffies = jiffies;
 816         mult = ((u64)delta) << rt_hash_log;
 817         if (ip_rt_gc_timeout > 1)
 818                 do_div(mult, ip_rt_gc_timeout);
 819         goal = (unsigned int)mult;
 820         if (goal > rt_hash_mask)
 821                 goal = rt_hash_mask + 1;
 822         for (; goal > 0; goal--) {
 823                 unsigned long tmo = ip_rt_gc_timeout;
 824                 unsigned long length;
 825
 826                 i = (i + 1) & rt_hash_mask;
 827                 rthp = &rt_hash_table[i].chain;
 828
 829                 if (need_resched())
 830                         cond_resched();
 831
 832                 samples++;
 833
 834                 if (rcu_dereference_raw(*rthp) == NULL)
 835                         continue;
 836                 length = 0;
 837                 spin_lock_bh(rt_hash_lock_addr(i));
 838                 while ((rth = rcu_dereference_protected(*rthp,
 839                                         lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
 840                         prefetch(rth->dst.rt_next);
 841                         if (rt_is_expired(rth) ||
 842                             rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
 843                                 *rthp = rth->dst.rt_next;
 844                                 rt_free(rth);
 845                                 continue;
 846                         }
 847
 848                         /* We only count entries on a chain with equal
 849                          * hash inputs once so that entries for
 850                          * different QOS levels, and other non-hash
 851                          * input attributes don't unfairly skew the
 852                          * length computation
 853                          */
 854                         tmo >>= 1;
 855                         rthp = &rth->dst.rt_next;
 856                         length += has_noalias(rt_hash_table[i].chain, rth);
 857                 }
 858                 spin_unlock_bh(rt_hash_lock_addr(i));
 859                 sum += length;
 860                 sum2 += length*length;
 861         }
 862         if (samples) {
 863                 unsigned long avg = sum / samples;
 864                 unsigned long sd = int_sqrt(sum2 / samples - avg*avg);
 865                 rt_chain_length_max = max_t(unsigned long,
 866                                         ip_rt_gc_elasticity,
 867                                         (avg + 4*sd) >> FRACT_BITS);
 868         }
 869         rover = i;
 870 }
 871
 872 /*
 873  * rt_worker_func() is run in process context.
 874  * we call rt_check_expire() to scan part of the hash table
 875  */
 876 static void rt_worker_func(struct work_struct *work)
 877 {
 878         rt_check_expire();
 879         schedule_delayed_work(&expires_work, ip_rt_gc_interval);
 880 }
 881
 882 /*
 883  * Perturbation of rt_genid by a small quantity [1..256]
 884  * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
 885  * many times (2^24) without giving recent rt_genid.
 886  * Jenkins hash is strong enough that litle changes of rt_genid are OK.
 887  */
 888 static void rt_cache_invalidate(struct net *net)
 889 {
 890         unsigned char shuffle;
 891
 892         get_random_bytes(&shuffle, sizeof(shuffle));
 893         atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
 894 }
 895
 896 /*
 897  * delay < 0  : invalidate cache (fast : entries will be deleted later)
 898  * delay >= 0 : invalidate & flush cache (can be long)
 899  */
 900 void rt_cache_flush(struct net *net, int delay)
 901 {
 902         rt_cache_invalidate(net);
 903         if (delay >= 0)
 904                 rt_do_flush(net, !in_softirq());
 905 }
 906
 907 /* Flush previous cache invalidated entries from the cache */
 908 void rt_cache_flush_batch(struct net *net)
 909 {
 910         rt_do_flush(net, !in_softirq());
 911 }
 912
 913 static void rt_emergency_hash_rebuild(struct net *net)
 914 {
 915         net_warn_ratelimited("Route hash chain too long!\n");
 916         rt_cache_invalidate(net);
 917 }
 918
 919 /*
 920    Short description of GC goals.
 921
 922    We want to build algorithm, which will keep routing cache
 923    at some equilibrium point, when number of aged off entries
 924    is kept approximately equal to newly generated ones.
 925
 926    Current expiration strength is variable "expire".
 927    We try to adjust it dynamically, so that if networking
 928    is idle expires is large enough to keep enough of warm entries,
 929    and when load increases it reduces to limit cache size.
 930  */
 931
 932 static int rt_garbage_collect(struct dst_ops *ops)
 933 {
 934         static unsigned long expire = RT_GC_TIMEOUT;
 935         static unsigned long last_gc;
 936         static int rover;
 937         static int equilibrium;
 938         struct rtable *rth;
 939         struct rtable __rcu **rthp;
 940         unsigned long now = jiffies;
 941         int goal;
 942         int entries = dst_entries_get_fast(&ipv4_dst_ops);
 943
 944         /*
 945          * Garbage collection is pretty expensive,
 946          * do not make it too frequently.
 947          */
 948
 949         RT_CACHE_STAT_INC(gc_total);
 950
 951         if (now - last_gc < ip_rt_gc_min_interval &&
 952             entries < ip_rt_max_size) {
 953                 RT_CACHE_STAT_INC(gc_ignored);
 954                 goto out;
 955         }
 956
 957         entries = dst_entries_get_slow(&ipv4_dst_ops);
 958         /* Calculate number of entries, which we want to expire now. */
 959         goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
 960         if (goal <= 0) {
 961                 if (equilibrium < ipv4_dst_ops.gc_thresh)
 962                         equilibrium = ipv4_dst_ops.gc_thresh;
 963                 goal = entries - equilibrium;
 964                 if (goal > 0) {
 965                         equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
 966                         goal = entries - equilibrium;
 967                 }
 968         } else {
 969                 /* We are in dangerous area. Try to reduce cache really
 970                  * aggressively.
 971                  */
 972                 goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
 973                 equilibrium = entries - goal;
 974         }
 975
 976         if (now - last_gc >= ip_rt_gc_min_interval)
 977                 last_gc = now;
 978
 979         if (goal <= 0) {
 980                 equilibrium += goal;
 981                 goto work_done;
 982         }
 983
 984         do {
 985                 int i, k;
 986
 987                 for (i = rt_hash_mask, k = rover; i >= 0; i--) {
 988                         unsigned long tmo = expire;
 989
 990                         k = (k + 1) & rt_hash_mask;
 991                         rthp = &rt_hash_table[k].chain;
 992                         spin_lock_bh(rt_hash_lock_addr(k));
 993                         while ((rth = rcu_dereference_protected(*rthp,
 994                                         lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
 995                                 if (!rt_is_expired(rth) &&
 996                                         !rt_may_expire(rth, tmo, expire)) {
 997                                         tmo >>= 1;
 998                                         rthp = &rth->dst.rt_next;
 999                                         continue;
1000                                 }
1001                                 *rthp = rth->dst.rt_next;
1002                                 rt_free(rth);
1003                                 goal--;
1004                         }
1005                         spin_unlock_bh(rt_hash_lock_addr(k));
1006                         if (goal <= 0)
1007                                 break;
1008                 }
1009                 rover = k;
1010
1011                 if (goal <= 0)
1012                         goto work_done;
1013
1014                 /* Goal is not achieved. We stop process if:
1015
1016                    - if expire reduced to zero. Otherwise, expire is halfed.
1017                    - if table is not full.
1018                    - if we are called from interrupt.
1019                    - jiffies check is just fallback/debug loop breaker.
1020                      We will not spin here for long time in any case.
1021                  */
1022
1023                 RT_CACHE_STAT_INC(gc_goal_miss);
1024
1025                 if (expire == 0)
1026                         break;
1027
1028                 expire >>= 1;
1029
1030                 if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1031                         goto out;
1032         } while (!in_softirq() && time_before_eq(jiffies, now));
1033
1034         if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
1035                 goto out;
1036         if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
1037                 goto out;
1038         net_warn_ratelimited("dst cache overflow\n");
1039         RT_CACHE_STAT_INC(gc_dst_overflow);
1040         return 1;
1041
1042 work_done:
1043         expire += ip_rt_gc_min_interval;
1044         if (expire > ip_rt_gc_timeout ||
1045             dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
1046             dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
1047                 expire = ip_rt_gc_timeout;
1048 out:    return 0;
1049 }
1050
1051 /*
1052  * Returns number of entries in a hash chain that have different hash_inputs
1053  */
1054 static int slow_chain_length(const struct rtable *head)
1055 {
1056         int length = 0;
1057         const struct rtable *rth = head;
1058
1059         while (rth) {
1060                 length += has_noalias(head, rth);
1061                 rth = rcu_dereference_protected(rth->dst.rt_next, 1);
1062         }
1063         return length >> FRACT_BITS;
1064 }
1065
1066 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
1067                                            struct sk_buff *skb,
1068                                            const void *daddr)
1069 {
1070         struct net_device *dev = dst->dev;
1071         const __be32 *pkey = daddr;
1072         const struct rtable *rt;
1073         struct neighbour *n;
1074
1075         rt = (const struct rtable *) dst;
1076         if (rt->rt_gateway)
1077                 pkey = (const __be32 *) &rt->rt_gateway;
1078         else if (skb)
1079                 pkey = &ip_hdr(skb)->daddr;
1080
1081         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
1082         if (n)
1083                 return n;
1084         return neigh_create(&arp_tbl, pkey, dev);
1085 }
1086
1087 static struct rtable *rt_intern_hash(unsigned int hash, struct rtable *rt,
1088                                      struct sk_buff *skb, int ifindex)
1089 {
1090         struct rtable   *rth, *cand;
1091         struct rtable __rcu **rthp, **candp;
1092         unsigned long   now;
1093         u32             min_score;
1094         int             chain_length;
1095
1096 restart:
1097         chain_length = 0;
1098         min_score = ~(u32)0;
1099         cand = NULL;
1100         candp = NULL;
1101         now = jiffies;
1102
1103         if (!rt_caching(dev_net(rt->dst.dev)) || (rt->dst.flags & DST_NOCACHE)) {
1104                 /*
1105                  * If we're not caching, just tell the caller we
1106                  * were successful and don't touch the route.  The
1107                  * caller hold the sole reference to the cache entry, and
1108                  * it will be released when the caller is done with it.
1109                  * If we drop it here, the callers have no way to resolve routes
1110                  * when we're not caching.  Instead, just point *rp at rt, so
1111                  * the caller gets a single use out of the route
1112                  * Note that we do rt_free on this new route entry, so that
1113                  * once its refcount hits zero, we are still able to reap it
1114                  * (Thanks Alexey)
1115                  * Note: To avoid expensive rcu stuff for this uncached dst,
1116                  * we set DST_NOCACHE so that dst_release() can free dst without
1117                  * waiting a grace period.
1118                  */
1119
1120                 rt->dst.flags |= DST_NOCACHE;
1121                 goto skip_hashing;
1122         }
1123
1124         rthp = &rt_hash_table[hash].chain;
1125
1126         spin_lock_bh(rt_hash_lock_addr(hash));
1127         while ((rth = rcu_dereference_protected(*rthp,
1128                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1129                 if (rt_is_expired(rth)) {
1130                         *rthp = rth->dst.rt_next;
1131                         rt_free(rth);
1132                         continue;
1133                 }
1134                 if (compare_keys(rth, rt) && compare_netns(rth, rt)) {
1135                         /* Put it first */
1136                         *rthp = rth->dst.rt_next;
1137                         /*
1138                          * Since lookup is lockfree, the deletion
1139                          * must be visible to another weakly ordered CPU before
1140                          * the insertion at the start of the hash chain.
1141                          */
1142                         rcu_assign_pointer(rth->dst.rt_next,
1143                                            rt_hash_table[hash].chain);
1144                         /*
1145                          * Since lookup is lockfree, the update writes
1146                          * must be ordered for consistency on SMP.
1147                          */
1148                         rcu_assign_pointer(rt_hash_table[hash].chain, rth);
1149
1150                         dst_use(&rth->dst, now);
1151                         spin_unlock_bh(rt_hash_lock_addr(hash));
1152
1153                         rt_drop(rt);
1154                         if (skb)
1155                                 skb_dst_set(skb, &rth->dst);
1156                         return rth;
1157                 }
1158
1159                 if (!atomic_read(&rth->dst.__refcnt)) {
1160                         u32 score = rt_score(rth);
1161
1162                         if (score <= min_score) {
1163                                 cand = rth;
1164                                 candp = rthp;
1165                                 min_score = score;
1166                         }
1167                 }
1168
1169                 chain_length++;
1170
1171                 rthp = &rth->dst.rt_next;
1172         }
1173
1174         if (cand) {
1175                 /* ip_rt_gc_elasticity used to be average length of chain
1176                  * length, when exceeded gc becomes really aggressive.
1177                  *
1178                  * The second limit is less certain. At the moment it allows
1179                  * only 2 entries per bucket. We will see.
1180                  */
1181                 if (chain_length > ip_rt_gc_elasticity) {
1182                         *candp = cand->dst.rt_next;
1183                         rt_free(cand);
1184                 }
1185         } else {
1186                 if (chain_length > rt_chain_length_max &&
1187                     slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
1188                         struct net *net = dev_net(rt->dst.dev);
1189                         int num = ++net->ipv4.current_rt_cache_rebuild_count;
1190                         if (!rt_caching(net)) {
1191                                 pr_warn("%s: %d rebuilds is over limit, route caching disabled\n",
1192                                         rt->dst.dev->name, num);
1193                         }
1194                         rt_emergency_hash_rebuild(net);
1195                         spin_unlock_bh(rt_hash_lock_addr(hash));
1196
1197                         hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1198                                         ifindex, rt_genid(net));
1199                         goto restart;
1200                 }
1201         }
1202
1203         rt->dst.rt_next = rt_hash_table[hash].chain;
1204
1205         /*
1206          * Since lookup is lockfree, we must make sure
1207          * previous writes to rt are committed to memory
1208          * before making rt visible to other CPUS.
1209          */
1210         rcu_assign_pointer(rt_hash_table[hash].chain, rt);
1211
1212         spin_unlock_bh(rt_hash_lock_addr(hash));
1213
1214 skip_hashing:
1215         if (skb)
1216                 skb_dst_set(skb, &rt->dst);
1217         return rt;
1218 }
1219
1220 /*
1221  * Peer allocation may fail only in serious out-of-memory conditions.  However
1222  * we still can generate some output.
1223  * Random ID selection looks a bit dangerous because we have no chances to
1224  * select ID being unique in a reasonable period of time.
1225  * But broken packet identifier may be better than no packet at all.
1226  */
1227 static void ip_select_fb_ident(struct iphdr *iph)
1228 {
1229         static DEFINE_SPINLOCK(ip_fb_id_lock);
1230         static u32 ip_fallback_id;
1231         u32 salt;
1232
1233         spin_lock_bh(&ip_fb_id_lock);
1234         salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
1235         iph->id = htons(salt & 0xFFFF);
1236         ip_fallback_id = salt;
1237         spin_unlock_bh(&ip_fb_id_lock);
1238 }
1239
1240 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
1241 {
1242         struct net *net = dev_net(dst->dev);
1243         struct inet_peer *peer;
1244
1245         peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
1246         if (peer) {
1247                 iph->id = htons(inet_getid(peer, more));
1248                 inet_putpeer(peer);
1249                 return;
1250         }
1251
1252         ip_select_fb_ident(iph);
1253 }
1254 EXPORT_SYMBOL(__ip_select_ident);
1255
1256 static void rt_del(unsigned int hash, struct rtable *rt)
1257 {
1258         struct rtable __rcu **rthp;
1259         struct rtable *aux;
1260
1261         rthp = &rt_hash_table[hash].chain;
1262         spin_lock_bh(rt_hash_lock_addr(hash));
1263         ip_rt_put(rt);
1264         while ((aux = rcu_dereference_protected(*rthp,
1265                         lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
1266                 if (aux == rt || rt_is_expired(aux)) {
1267                         *rthp = aux->dst.rt_next;
1268                         rt_free(aux);
1269                         continue;
1270                 }
1271                 rthp = &aux->dst.rt_next;
1272         }
1273         spin_unlock_bh(rt_hash_lock_addr(hash));
1274 }
1275
1276 static void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb)
1277 {
1278         const struct iphdr *iph = (const struct iphdr *) skb->data;
1279         __be32 new_gw = icmp_hdr(skb)->un.gateway;
1280         __be32 old_gw = ip_hdr(skb)->saddr;
1281         struct net_device *dev = skb->dev;
1282         __be32 daddr = iph->daddr;
1283         __be32 saddr = iph->saddr;
1284         struct in_device *in_dev;
1285         struct neighbour *n;
1286         struct rtable *rt;
1287         struct net *net;
1288
1289         switch (icmp_hdr(skb)->code & 7) {
1290         case ICMP_REDIR_NET:
1291         case ICMP_REDIR_NETTOS:
1292         case ICMP_REDIR_HOST:
1293         case ICMP_REDIR_HOSTTOS:
1294                 break;
1295
1296         default:
1297                 return;
1298         }
1299
1300         rt = (struct rtable *) dst;
1301         if (rt->rt_gateway != old_gw)
1302                 return;
1303
1304         in_dev = __in_dev_get_rcu(dev);
1305         if (!in_dev)
1306                 return;
1307
1308         net = dev_net(dev);
1309         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
1310             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
1311             ipv4_is_zeronet(new_gw))
1312                 goto reject_redirect;
1313
1314         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
1315                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
1316                         goto reject_redirect;
1317                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
1318                         goto reject_redirect;
1319         } else {
1320                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
1321                         goto reject_redirect;
1322         }
1323
1324         n = ipv4_neigh_lookup(dst, NULL, &new_gw);
1325         if (n) {
1326                 if (!(n->nud_state & NUD_VALID)) {
1327                         neigh_event_send(n, NULL);
1328                 } else {
1329                         rt->rt_gateway = new_gw;
1330                         rt->rt_flags |= RTCF_REDIRECTED;
1331                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
1332                 }
1333                 neigh_release(n);
1334         }
1335         return;
1336
1337 reject_redirect:
1338 #ifdef CONFIG_IP_ROUTE_VERBOSE
1339         if (IN_DEV_LOG_MARTIANS(in_dev))
1340                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
1341                                      "  Advised path = %pI4 -> %pI4\n",
1342                                      &old_gw, dev->name, &new_gw,
1343                                      &saddr, &daddr);
1344 #endif
1345         ;
1346 }
1347
1348 /* called in rcu_read_lock() section */
1349 void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
1350 {
1351         const struct iphdr *iph = (const struct iphdr *) skb->data;
1352         __be32 daddr = iph->daddr;
1353         __be32 saddr = iph->saddr;
1354         struct net_device *dev = skb->dev;
1355         int    ikeys[2] = { dev->ifindex, 0 };
1356         __be32 skeys[2] = { saddr, 0 };
1357         struct net *net;
1358         int s, i;
1359
1360         net = dev_net(dev);
1361         for (s = 0; s < 2; s++) {
1362                 for (i = 0; i < 2; i++) {
1363                         unsigned int hash;
1364                         struct rtable __rcu **rthp;
1365                         struct rtable *rt;
1366
1367                         hash = rt_hash(daddr, skeys[s], ikeys[i], rt_genid(net));
1368
1369                         rthp = &rt_hash_table[hash].chain;
1370
1371                         while ((rt = rcu_dereference(*rthp)) != NULL) {
1372                                 rthp = &rt->dst.rt_next;
1373
1374                                 if (rt->rt_key_dst != daddr ||
1375                                     rt->rt_key_src != skeys[s] ||
1376                                     rt->rt_oif != ikeys[i] ||
1377                                     rt_is_input_route(rt) ||
1378                                     rt_is_expired(rt) ||
1379                                     !net_eq(dev_net(rt->dst.dev), net) ||
1380                                     rt->dst.error ||
1381                                     rt->dst.dev != dev)
1382                                         continue;
1383
1384                                 ip_do_redirect(&rt->dst, skb);
1385                         }
1386                 }
1387         }
1388         return;
1389
1390 }
1391
1392 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
1393 {
1394         struct rtable *rt = (struct rtable *)dst;
1395         struct dst_entry *ret = dst;
1396
1397         if (rt) {
1398                 if (dst->obsolete > 0) {
1399                         ip_rt_put(rt);
1400                         ret = NULL;
1401                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
1402                            rt->dst.expires) {
1403                         unsigned int hash = rt_hash(rt->rt_key_dst, rt->rt_key_src,
1404                                                 rt->rt_oif,
1405                                                 rt_genid(dev_net(dst->dev)));
1406                         rt_del(hash, rt);
1407                         ret = NULL;
1408                 }
1409         }
1410         return ret;
1411 }
1412
1413 /*
1414  * Algorithm:
1415  *      1. The first ip_rt_redirect_number redirects are sent
1416  *         with exponential backoff, then we stop sending them at all,
1417  *         assuming that the host ignores our redirects.
1418  *      2. If we did not see packets requiring redirects
1419  *         during ip_rt_redirect_silence, we assume that the host
1420  *         forgot redirected route and start to send redirects again.
1421  *
1422  * This algorithm is much cheaper and more intelligent than dumb load limiting
1423  * in icmp.c.
1424  *
1425  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
1426  * and "frag. need" (breaks PMTU discovery) in icmp.c.
1427  */
1428
1429 void ip_rt_send_redirect(struct sk_buff *skb)
1430 {
1431         struct rtable *rt = skb_rtable(skb);
1432         struct in_device *in_dev;
1433         struct inet_peer *peer;
1434         struct net *net;
1435         int log_martians;
1436
1437         rcu_read_lock();
1438         in_dev = __in_dev_get_rcu(rt->dst.dev);
1439         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
1440                 rcu_read_unlock();
1441                 return;
1442         }
1443         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
1444         rcu_read_unlock();
1445
1446         net = dev_net(rt->dst.dev);
1447         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
1448         if (!peer) {
1449                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1450                 return;
1451         }
1452
1453         /* No redirected packets during ip_rt_redirect_silence;
1454          * reset the algorithm.
1455          */
1456         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
1457                 peer->rate_tokens = 0;
1458
1459         /* Too many ignored redirects; do not send anything
1460          * set dst.rate_last to the last seen redirected packet.
1461          */
1462         if (peer->rate_tokens >= ip_rt_redirect_number) {
1463                 peer->rate_last = jiffies;
1464                 goto out_put_peer;
1465         }
1466
1467         /* Check for load limit; set rate_last to the latest sent
1468          * redirect.
1469          */
1470         if (peer->rate_tokens == 0 ||
1471             time_after(jiffies,
1472                        (peer->rate_last +
1473                         (ip_rt_redirect_load << peer->rate_tokens)))) {
1474                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
1475                 peer->rate_last = jiffies;
1476                 ++peer->rate_tokens;
1477 #ifdef CONFIG_IP_ROUTE_VERBOSE
1478                 if (log_martians &&
1479                     peer->rate_tokens == ip_rt_redirect_number)
1480                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
1481                                              &ip_hdr(skb)->saddr, rt->rt_iif,
1482                                              &rt->rt_dst, &rt->rt_gateway);
1483 #endif
1484         }
1485 out_put_peer:
1486         inet_putpeer(peer);
1487 }
1488
1489 static int ip_error(struct sk_buff *skb)
1490 {
1491         struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
1492         struct rtable *rt = skb_rtable(skb);
1493         struct inet_peer *peer;
1494         unsigned long now;
1495         struct net *net;
1496         bool send;
1497         int code;
1498
1499         net = dev_net(rt->dst.dev);
1500         if (!IN_DEV_FORWARD(in_dev)) {
1501                 switch (rt->dst.error) {
1502                 case EHOSTUNREACH:
1503                         IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
1504                         break;
1505
1506                 case ENETUNREACH:
1507                         IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1508                         break;
1509                 }
1510                 goto out;
1511         }
1512
1513         switch (rt->dst.error) {
1514         case EINVAL:
1515         default:
1516                 goto out;
1517         case EHOSTUNREACH:
1518                 code = ICMP_HOST_UNREACH;
1519                 break;
1520         case ENETUNREACH:
1521                 code = ICMP_NET_UNREACH;
1522                 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
1523                 break;
1524         case EACCES:
1525                 code = ICMP_PKT_FILTERED;
1526                 break;
1527         }
1528
1529         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
1530
1531         send = true;
1532         if (peer) {
1533                 now = jiffies;
1534                 peer->rate_tokens += now - peer->rate_last;
1535                 if (peer->rate_tokens > ip_rt_error_burst)
1536                         peer->rate_tokens = ip_rt_error_burst;
1537                 peer->rate_last = now;
1538                 if (peer->rate_tokens >= ip_rt_error_cost)
1539                         peer->rate_tokens -= ip_rt_error_cost;
1540                 else
1541                         send = false;
1542                 inet_putpeer(peer);
1543         }
1544         if (send)
1545                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1546
1547 out:    kfree_skb(skb);
1548         return 0;
1549 }
1550
1551 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
1552 {
1553         struct rtable *rt = (struct rtable *) dst;
1554
1555         dst_confirm(dst);
1556
1557         if (mtu < ip_rt_min_pmtu)
1558                 mtu = ip_rt_min_pmtu;
1559
1560         rt->rt_pmtu = mtu;
1561         dst_set_expires(&rt->dst, ip_rt_mtu_expires);
1562 }
1563
1564 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1565                       int oif, u32 mark, u8 protocol, int flow_flags)
1566 {
1567         const struct iphdr *iph = (const struct iphdr *)skb->data;
1568         struct flowi4 fl4;
1569         struct rtable *rt;
1570
1571         flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
1572                            protocol, flow_flags,
1573                            iph->daddr, iph->saddr, 0, 0);
1574         rt = __ip_route_output_key(net, &fl4);
1575         if (!IS_ERR(rt)) {
1576                 ip_rt_update_pmtu(&rt->dst, mtu);
1577                 ip_rt_put(rt);
1578         }
1579 }
1580 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1581
1582 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1583 {
1584         const struct inet_sock *inet = inet_sk(sk);
1585
1586         return ipv4_update_pmtu(skb, sock_net(sk), mtu,
1587                                 sk->sk_bound_dev_if, sk->sk_mark,
1588                                 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
1589                                 inet_sk_flowi_flags(sk));
1590 }
1591 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1592
1593 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1594 {
1595         struct rtable *rt = (struct rtable *) dst;
1596
1597         if (rt_is_expired(rt))
1598                 return NULL;
1599         return dst;
1600 }
1601
1602 static void ipv4_dst_destroy(struct dst_entry *dst)
1603 {
1604         struct rtable *rt = (struct rtable *) dst;
1605
1606         if (rt->fi) {
1607                 fib_info_put(rt->fi);
1608                 rt->fi = NULL;
1609         }
1610 }
1611
1612
1613 static void ipv4_link_failure(struct sk_buff *skb)
1614 {
1615         struct rtable *rt;
1616
1617         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1618
1619         rt = skb_rtable(skb);
1620         if (rt)
1621                 dst_set_expires(&rt->dst, 0);
1622 }
1623
1624 static int ip_rt_bug(struct sk_buff *skb)
1625 {
1626         pr_debug("%s: %pI4 -> %pI4, %s\n",
1627                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1628                  skb->dev ? skb->dev->name : "?");
1629         kfree_skb(skb);
1630         WARN_ON(1);
1631         return 0;
1632 }
1633
1634 /*
1635    We do not cache source address of outgoing interface,
1636    because it is used only by IP RR, TS and SRR options,
1637    so that it out of fast path.
1638
1639    BTW remember: "addr" is allowed to be not aligned
1640    in IP options!
1641  */
1642
1643 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1644 {
1645         __be32 src;
1646
1647         if (rt_is_output_route(rt))
1648                 src = ip_hdr(skb)->saddr;
1649         else {
1650                 struct fib_result res;
1651                 struct flowi4 fl4;
1652                 struct iphdr *iph;
1653
1654                 iph = ip_hdr(skb);
1655
1656                 memset(&fl4, 0, sizeof(fl4));
1657                 fl4.daddr = iph->daddr;
1658                 fl4.saddr = iph->saddr;
1659                 fl4.flowi4_tos = RT_TOS(iph->tos);
1660                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1661                 fl4.flowi4_iif = skb->dev->ifindex;
1662                 fl4.flowi4_mark = skb->mark;
1663
1664                 rcu_read_lock();
1665                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1666                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1667                 else
1668                         src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
1669                                         RT_SCOPE_UNIVERSE);
1670                 rcu_read_unlock();
1671         }
1672         memcpy(addr, &src, 4);
1673 }
1674
1675 #ifdef CONFIG_IP_ROUTE_CLASSID
1676 static void set_class_tag(struct rtable *rt, u32 tag)
1677 {
1678         if (!(rt->dst.tclassid & 0xFFFF))
1679                 rt->dst.tclassid |= tag & 0xFFFF;
1680         if (!(rt->dst.tclassid & 0xFFFF0000))
1681                 rt->dst.tclassid |= tag & 0xFFFF0000;
1682 }
1683 #endif
1684
1685 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1686 {
1687         unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1688
1689         if (advmss == 0) {
1690                 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1691                                ip_rt_min_advmss);
1692                 if (advmss > 65535 - 40)
1693                         advmss = 65535 - 40;
1694         }
1695         return advmss;
1696 }
1697
1698 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1699 {
1700         const struct rtable *rt = (const struct rtable *) dst;
1701         unsigned int mtu = rt->rt_pmtu;
1702
1703         if (mtu && time_after_eq(jiffies, rt->dst.expires))
1704                 mtu = 0;
1705
1706         if (!mtu)
1707                 mtu = dst_metric_raw(dst, RTAX_MTU);
1708
1709         if (mtu && rt_is_output_route(rt))
1710                 return mtu;
1711
1712         mtu = dst->dev->mtu;
1713
1714         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1715
1716                 if (rt->rt_gateway != rt->rt_dst && mtu > 576)
1717                         mtu = 576;
1718         }
1719
1720         if (mtu > IP_MAX_MTU)
1721                 mtu = IP_MAX_MTU;
1722
1723         return mtu;
1724 }
1725
1726 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
1727                             struct fib_info *fi)
1728 {
1729         if (fi->fib_metrics != (u32 *) dst_default_metrics) {
1730                 rt->fi = fi;
1731                 atomic_inc(&fi->fib_clntref);
1732         }
1733         dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1734 }
1735
1736 static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4,
1737                            const struct fib_result *res,
1738                            struct fib_info *fi, u16 type, u32 itag)
1739 {
1740         if (fi) {
1741                 if (FIB_RES_GW(*res) &&
1742                     FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
1743                         rt->rt_gateway = FIB_RES_GW(*res);
1744                 rt_init_metrics(rt, fl4, fi);
1745 #ifdef CONFIG_IP_ROUTE_CLASSID
1746                 rt->dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
1747 #endif
1748         }
1749
1750 #ifdef CONFIG_IP_ROUTE_CLASSID
1751 #ifdef CONFIG_IP_MULTIPLE_TABLES
1752         set_class_tag(rt, fib_rules_tclass(res));
1753 #endif
1754         set_class_tag(rt, itag);
1755 #endif
1756 }
1757
1758 static struct rtable *rt_dst_alloc(struct net_device *dev,
1759                                    bool nopolicy, bool noxfrm)
1760 {
1761         return dst_alloc(&ipv4_dst_ops, dev, 1, -1,
1762                          DST_HOST |
1763                          (nopolicy ? DST_NOPOLICY : 0) |
1764                          (noxfrm ? DST_NOXFRM : 0));
1765 }
1766
1767 /* called in rcu_read_lock() section */
1768 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1769                                 u8 tos, struct net_device *dev, int our)
1770 {
1771         unsigned int hash;
1772         struct rtable *rth;
1773         struct in_device *in_dev = __in_dev_get_rcu(dev);
1774         u32 itag = 0;
1775         int err;
1776
1777         /* Primary sanity checks. */
1778
1779         if (in_dev == NULL)
1780                 return -EINVAL;
1781
1782         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1783             skb->protocol != htons(ETH_P_IP))
1784                 goto e_inval;
1785
1786         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1787                 if (ipv4_is_loopback(saddr))
1788                         goto e_inval;
1789
1790         if (ipv4_is_zeronet(saddr)) {
1791                 if (!ipv4_is_local_multicast(daddr))
1792                         goto e_inval;
1793         } else {
1794                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1795                                           in_dev, &itag);
1796                 if (err < 0)
1797                         goto e_err;
1798         }
1799         rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1800                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1801         if (!rth)
1802                 goto e_nobufs;
1803
1804 #ifdef CONFIG_IP_ROUTE_CLASSID
1805         rth->dst.tclassid = itag;
1806 #endif
1807         rth->dst.output = ip_rt_bug;
1808
1809         rth->rt_key_dst = daddr;
1810         rth->rt_key_src = saddr;
1811         rth->rt_genid   = rt_genid(dev_net(dev));
1812         rth->rt_flags   = RTCF_MULTICAST;
1813         rth->rt_type    = RTN_MULTICAST;
1814         rth->rt_key_tos = tos;
1815         rth->rt_dst     = daddr;
1816         rth->rt_src     = saddr;
1817         rth->rt_route_iif = dev->ifindex;
1818         rth->rt_iif     = dev->ifindex;
1819         rth->rt_oif     = 0;
1820         rth->rt_mark    = skb->mark;
1821         rth->rt_pmtu    = 0;
1822         rth->rt_gateway = daddr;
1823         rth->fi = NULL;
1824         if (our) {
1825                 rth->dst.input= ip_local_deliver;
1826                 rth->rt_flags |= RTCF_LOCAL;
1827         }
1828
1829 #ifdef CONFIG_IP_MROUTE
1830         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1831                 rth->dst.input = ip_mr_input;
1832 #endif
1833         RT_CACHE_STAT_INC(in_slow_mc);
1834
1835         hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
1836         rth = rt_intern_hash(hash, rth, skb, dev->ifindex);
1837         return IS_ERR(rth) ? PTR_ERR(rth) : 0;
1838
1839 e_nobufs:
1840         return -ENOBUFS;
1841 e_inval:
1842         return -EINVAL;
1843 e_err:
1844         return err;
1845 }
1846
1847
1848 static void ip_handle_martian_source(struct net_device *dev,
1849                                      struct in_device *in_dev,
1850                                      struct sk_buff *skb,
1851                                      __be32 daddr,
1852                                      __be32 saddr)
1853 {
1854         RT_CACHE_STAT_INC(in_martian_src);
1855 #ifdef CONFIG_IP_ROUTE_VERBOSE
1856         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1857                 /*
1858                  *      RFC1812 recommendation, if source is martian,
1859                  *      the only hint is MAC header.
1860                  */
1861                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1862                         &daddr, &saddr, dev->name);
1863                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1864                         print_hex_dump(KERN_WARNING, "ll header: ",
1865                                        DUMP_PREFIX_OFFSET, 16, 1,
1866                                        skb_mac_header(skb),
1867                                        dev->hard_header_len, true);
1868                 }
1869         }
1870 #endif
1871 }
1872
1873 /* called in rcu_read_lock() section */
1874 static int __mkroute_input(struct sk_buff *skb,
1875                            const struct fib_result *res,
1876                            struct in_device *in_dev,
1877                            __be32 daddr, __be32 saddr, u32 tos,
1878                            struct rtable **result)
1879 {
1880         struct rtable *rth;
1881         int err;
1882         struct in_device *out_dev;
1883         unsigned int flags = 0;
1884         u32 itag;
1885
1886         /* get a working reference to the output device */
1887         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1888         if (out_dev == NULL) {
1889                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1890                 return -EINVAL;
1891         }
1892
1893
1894         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1895                                   in_dev->dev, in_dev, &itag);
1896         if (err < 0) {
1897                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1898                                          saddr);
1899
1900                 goto cleanup;
1901         }
1902
1903         if (err)
1904                 flags |= RTCF_DIRECTSRC;
1905
1906         if (out_dev == in_dev && err &&
1907             (IN_DEV_SHARED_MEDIA(out_dev) ||
1908              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1909                 flags |= RTCF_DOREDIRECT;
1910
1911         if (skb->protocol != htons(ETH_P_IP)) {
1912                 /* Not IP (i.e. ARP). Do not create route, if it is
1913                  * invalid for proxy arp. DNAT routes are always valid.
1914                  *
1915                  * Proxy arp feature have been extended to allow, ARP
1916                  * replies back to the same interface, to support
1917                  * Private VLAN switch technologies. See arp.c.
1918                  */
1919                 if (out_dev == in_dev &&
1920                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1921                         err = -EINVAL;
1922                         goto cleanup;
1923                 }
1924         }
1925
1926         rth = rt_dst_alloc(out_dev->dev,
1927                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1928                            IN_DEV_CONF_GET(out_dev, NOXFRM));
1929         if (!rth) {
1930                 err = -ENOBUFS;
1931                 goto cleanup;
1932         }
1933
1934         rth->rt_key_dst = daddr;
1935         rth->rt_key_src = saddr;
1936         rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1937         rth->rt_flags = flags;
1938         rth->rt_type = res->type;
1939         rth->rt_key_tos = tos;
1940         rth->rt_dst     = daddr;
1941         rth->rt_src     = saddr;
1942         rth->rt_route_iif = in_dev->dev->ifindex;
1943         rth->rt_iif     = in_dev->dev->ifindex;
1944         rth->rt_oif     = 0;
1945         rth->rt_mark    = skb->mark;
1946         rth->rt_pmtu    = 0;
1947         rth->rt_gateway = daddr;
1948         rth->fi = NULL;
1949
1950         rth->dst.input = ip_forward;
1951         rth->dst.output = ip_output;
1952
1953         rt_set_nexthop(rth, NULL, res, res->fi, res->type, itag);
1954
1955         *result = rth;
1956         err = 0;
1957  cleanup:
1958         return err;
1959 }
1960
1961 static int ip_mkroute_input(struct sk_buff *skb,
1962                             struct fib_result *res,
1963                             const struct flowi4 *fl4,
1964                             struct in_device *in_dev,
1965                             __be32 daddr, __be32 saddr, u32 tos)
1966 {
1967         struct rtable *rth = NULL;
1968         int err;
1969         unsigned int hash;
1970
1971 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1972         if (res->fi && res->fi->fib_nhs > 1)
1973                 fib_select_multipath(res);
1974 #endif
1975
1976         /* create a routing cache entry */
1977         err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1978         if (err)
1979                 return err;
1980
1981         /* put it into the cache */
1982         hash = rt_hash(daddr, saddr, fl4->flowi4_iif,
1983                        rt_genid(dev_net(rth->dst.dev)));
1984         rth = rt_intern_hash(hash, rth, skb, fl4->flowi4_iif);
1985         if (IS_ERR(rth))
1986                 return PTR_ERR(rth);
1987         return 0;
1988 }
1989
1990 /*
1991  *      NOTE. We drop all the packets that has local source
1992  *      addresses, because every properly looped back packet
1993  *      must have correct destination already attached by output routine.
1994  *
1995  *      Such approach solves two big problems:
1996  *      1. Not simplex devices are handled properly.
1997  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1998  *      called with rcu_read_lock()
1999  */
2000
2001 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2002                                u8 tos, struct net_device *dev)
2003 {
2004         struct fib_result res;
2005         struct in_device *in_dev = __in_dev_get_rcu(dev);
2006         struct flowi4   fl4;
2007         unsigned int    flags = 0;
2008         u32             itag = 0;
2009         struct rtable   *rth;
2010         unsigned int    hash;
2011         int             err = -EINVAL;
2012         struct net    *net = dev_net(dev);
2013
2014         /* IP on this device is disabled. */
2015
2016         if (!in_dev)
2017                 goto out;
2018
2019         /* Check for the most weird martians, which can be not detected
2020            by fib_lookup.
2021          */
2022
2023         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2024                 goto martian_source;
2025
2026         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2027                 goto brd_input;
2028
2029         /* Accept zero addresses only to limited broadcast;
2030          * I even do not know to fix it or not. Waiting for complains :-)
2031          */
2032         if (ipv4_is_zeronet(saddr))
2033                 goto martian_source;
2034
2035         if (ipv4_is_zeronet(daddr))
2036                 goto martian_destination;
2037
2038         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
2039                 if (ipv4_is_loopback(daddr))
2040                         goto martian_destination;
2041
2042                 if (ipv4_is_loopback(saddr))
2043                         goto martian_source;
2044         }
2045
2046         /*
2047          *      Now we are ready to route packet.
2048          */
2049         fl4.flowi4_oif = 0;
2050         fl4.flowi4_iif = dev->ifindex;
2051         fl4.flowi4_mark = skb->mark;
2052         fl4.flowi4_tos = tos;
2053         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2054         fl4.daddr = daddr;
2055         fl4.saddr = saddr;
2056         err = fib_lookup(net, &fl4, &res);
2057         if (err != 0)
2058                 goto no_route;
2059
2060         RT_CACHE_STAT_INC(in_slow_tot);
2061
2062         if (res.type == RTN_BROADCAST)
2063                 goto brd_input;
2064
2065         if (res.type == RTN_LOCAL) {
2066                 err = fib_validate_source(skb, saddr, daddr, tos,
2067                                           net->loopback_dev->ifindex,
2068                                           dev, in_dev, &itag);
2069                 if (err < 0)
2070                         goto martian_source_keep_err;
2071                 if (err)
2072                         flags |= RTCF_DIRECTSRC;
2073                 goto local_input;
2074         }
2075
2076         if (!IN_DEV_FORWARD(in_dev))
2077                 goto no_route;
2078         if (res.type != RTN_UNICAST)
2079                 goto martian_destination;
2080
2081         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
2082 out:    return err;
2083
2084 brd_input:
2085         if (skb->protocol != htons(ETH_P_IP))
2086                 goto e_inval;
2087
2088         if (!ipv4_is_zeronet(saddr)) {
2089                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2090                                           in_dev, &itag);
2091                 if (err < 0)
2092                         goto martian_source_keep_err;
2093                 if (err)
2094                         flags |= RTCF_DIRECTSRC;
2095         }
2096         flags |= RTCF_BROADCAST;
2097         res.type = RTN_BROADCAST;
2098         RT_CACHE_STAT_INC(in_brd);
2099
2100 local_input:
2101         rth = rt_dst_alloc(net->loopback_dev,
2102                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2103         if (!rth)
2104                 goto e_nobufs;
2105
2106         rth->dst.input= ip_local_deliver;
2107         rth->dst.output= ip_rt_bug;
2108 #ifdef CONFIG_IP_ROUTE_CLASSID
2109         rth->dst.tclassid = itag;
2110 #endif
2111
2112         rth->rt_key_dst = daddr;
2113         rth->rt_key_src = saddr;
2114         rth->rt_genid = rt_genid(net);
2115         rth->rt_flags   = flags|RTCF_LOCAL;
2116         rth->rt_type    = res.type;
2117         rth->rt_key_tos = tos;
2118         rth->rt_dst     = daddr;
2119         rth->rt_src     = saddr;
2120         rth->rt_route_iif = dev->ifindex;
2121         rth->rt_iif     = dev->ifindex;
2122         rth->rt_oif     = 0;
2123         rth->rt_mark    = skb->mark;
2124         rth->rt_pmtu    = 0;
2125         rth->rt_gateway = daddr;
2126         rth->fi = NULL;
2127         if (res.type == RTN_UNREACHABLE) {
2128                 rth->dst.input= ip_error;
2129                 rth->dst.error= -err;
2130                 rth->rt_flags   &= ~RTCF_LOCAL;
2131         }
2132         hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
2133         rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
2134         err = 0;
2135         if (IS_ERR(rth))
2136                 err = PTR_ERR(rth);
2137         goto out;
2138
2139 no_route:
2140         RT_CACHE_STAT_INC(in_no_route);
2141         res.type = RTN_UNREACHABLE;
2142         if (err == -ESRCH)
2143                 err = -ENETUNREACH;
2144         goto local_input;
2145
2146         /*
2147          *      Do not cache martian addresses: they should be logged (RFC1812)
2148          */
2149 martian_destination:
2150         RT_CACHE_STAT_INC(in_martian_dst);
2151 #ifdef CONFIG_IP_ROUTE_VERBOSE
2152         if (IN_DEV_LOG_MARTIANS(in_dev))
2153                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2154                                      &daddr, &saddr, dev->name);
2155 #endif
2156
2157 e_inval:
2158         err = -EINVAL;
2159         goto out;
2160
2161 e_nobufs:
2162         err = -ENOBUFS;
2163         goto out;
2164
2165 martian_source:
2166         err = -EINVAL;
2167 martian_source_keep_err:
2168         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2169         goto out;
2170 }
2171
2172 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2173                            u8 tos, struct net_device *dev, bool noref)
2174 {
2175         struct rtable   *rth;
2176         unsigned int    hash;
2177         int iif = dev->ifindex;
2178         struct net *net;
2179         int res;
2180
2181         net = dev_net(dev);
2182
2183         rcu_read_lock();
2184
2185         if (!rt_caching(net))
2186                 goto skip_cache;
2187
2188         tos &= IPTOS_RT_MASK;
2189         hash = rt_hash(daddr, saddr, iif, rt_genid(net));
2190
2191         for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2192              rth = rcu_dereference(rth->dst.rt_next)) {
2193                 if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) |
2194                      ((__force u32)rth->rt_key_src ^ (__force u32)saddr) |
2195                      (rth->rt_route_iif ^ iif) |
2196                      (rth->rt_key_tos ^ tos)) == 0 &&
2197                     rth->rt_mark == skb->mark &&
2198                     net_eq(dev_net(rth->dst.dev), net) &&
2199                     !rt_is_expired(rth)) {
2200                         if (noref) {
2201                                 dst_use_noref(&rth->dst, jiffies);
2202                                 skb_dst_set_noref(skb, &rth->dst);
2203                         } else {
2204                                 dst_use(&rth->dst, jiffies);
2205                                 skb_dst_set(skb, &rth->dst);
2206                         }
2207                         RT_CACHE_STAT_INC(in_hit);
2208                         rcu_read_unlock();
2209                         return 0;
2210                 }
2211                 RT_CACHE_STAT_INC(in_hlist_search);
2212         }
2213
2214 skip_cache:
2215         /* Multicast recognition logic is moved from route cache to here.
2216            The problem was that too many Ethernet cards have broken/missing
2217            hardware multicast filters :-( As result the host on multicasting
2218            network acquires a lot of useless route cache entries, sort of
2219            SDR messages from all the world. Now we try to get rid of them.
2220            Really, provided software IP multicast filter is organized
2221            reasonably (at least, hashed), it does not result in a slowdown
2222            comparing with route cache reject entries.
2223            Note, that multicast routers are not affected, because
2224            route cache entry is created eventually.
2225          */
2226         if (ipv4_is_multicast(daddr)) {
2227                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2228
2229                 if (in_dev) {
2230                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
2231                                                   ip_hdr(skb)->protocol);
2232                         if (our
2233 #ifdef CONFIG_IP_MROUTE
2234                                 ||
2235                             (!ipv4_is_local_multicast(daddr) &&
2236                              IN_DEV_MFORWARD(in_dev))
2237 #endif
2238                            ) {
2239                                 int res = ip_route_input_mc(skb, daddr, saddr,
2240                                                             tos, dev, our);
2241                                 rcu_read_unlock();
2242                                 return res;
2243                         }
2244                 }
2245                 rcu_read_unlock();
2246                 return -EINVAL;
2247         }
2248         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2249         rcu_read_unlock();
2250         return res;
2251 }
2252 EXPORT_SYMBOL(ip_route_input_common);
2253
2254 /* called with rcu_read_lock() */
2255 static struct rtable *__mkroute_output(const struct fib_result *res,
2256                                        const struct flowi4 *fl4,
2257                                        __be32 orig_daddr, __be32 orig_saddr,
2258                                        int orig_oif, __u8 orig_rtos,
2259                                        struct net_device *dev_out,
2260                                        unsigned int flags)
2261 {
2262         struct fib_info *fi = res->fi;
2263         struct in_device *in_dev;
2264         u16 type = res->type;
2265         struct rtable *rth;
2266
2267         in_dev = __in_dev_get_rcu(dev_out);
2268         if (!in_dev)
2269                 return ERR_PTR(-EINVAL);
2270
2271         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2272                 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2273                         return ERR_PTR(-EINVAL);
2274
2275         if (ipv4_is_lbcast(fl4->daddr))
2276                 type = RTN_BROADCAST;
2277         else if (ipv4_is_multicast(fl4->daddr))
2278                 type = RTN_MULTICAST;
2279         else if (ipv4_is_zeronet(fl4->daddr))
2280                 return ERR_PTR(-EINVAL);
2281
2282         if (dev_out->flags & IFF_LOOPBACK)
2283                 flags |= RTCF_LOCAL;
2284
2285         if (type == RTN_BROADCAST) {
2286                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2287                 fi = NULL;
2288         } else if (type == RTN_MULTICAST) {
2289                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2290                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2291                                      fl4->flowi4_proto))
2292                         flags &= ~RTCF_LOCAL;
2293                 /* If multicast route do not exist use
2294                  * default one, but do not gateway in this case.
2295                  * Yes, it is hack.
2296                  */
2297                 if (fi && res->prefixlen < 4)
2298                         fi = NULL;
2299         }
2300
2301         rth = rt_dst_alloc(dev_out,
2302                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2303                            IN_DEV_CONF_GET(in_dev, NOXFRM));
2304         if (!rth)
2305                 return ERR_PTR(-ENOBUFS);
2306
2307         rth->dst.output = ip_output;
2308
2309         rth->rt_key_dst = orig_daddr;
2310         rth->rt_key_src = orig_saddr;
2311         rth->rt_genid = rt_genid(dev_net(dev_out));
2312         rth->rt_flags   = flags;
2313         rth->rt_type    = type;
2314         rth->rt_key_tos = orig_rtos;
2315         rth->rt_dst     = fl4->daddr;
2316         rth->rt_src     = fl4->saddr;
2317         rth->rt_route_iif = 0;
2318         rth->rt_iif     = orig_oif ? : dev_out->ifindex;
2319         rth->rt_oif     = orig_oif;
2320         rth->rt_mark    = fl4->flowi4_mark;
2321         rth->rt_pmtu    = 0;
2322         rth->rt_gateway = fl4->daddr;
2323         rth->fi = NULL;
2324
2325         RT_CACHE_STAT_INC(out_slow_tot);
2326
2327         if (flags & RTCF_LOCAL)
2328                 rth->dst.input = ip_local_deliver;
2329         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2330                 if (flags & RTCF_LOCAL &&
2331                     !(dev_out->flags & IFF_LOOPBACK)) {
2332                         rth->dst.output = ip_mc_output;
2333                         RT_CACHE_STAT_INC(out_slow_mc);
2334                 }
2335 #ifdef CONFIG_IP_MROUTE
2336                 if (type == RTN_MULTICAST) {
2337                         if (IN_DEV_MFORWARD(in_dev) &&
2338                             !ipv4_is_local_multicast(fl4->daddr)) {
2339                                 rth->dst.input = ip_mr_input;
2340                                 rth->dst.output = ip_mc_output;
2341                         }
2342                 }
2343 #endif
2344         }
2345
2346         rt_set_nexthop(rth, fl4, res, fi, type, 0);
2347
2348         if (fl4->flowi4_flags & FLOWI_FLAG_RT_NOCACHE)
2349                 rth->dst.flags |= DST_NOCACHE;
2350
2351         return rth;
2352 }
2353
2354 /*
2355  * Major route resolver routine.
2356  * called with rcu_read_lock();
2357  */
2358
2359 static struct rtable *ip_route_output_slow(struct net *net, struct flowi4 *fl4)
2360 {
2361         struct net_device *dev_out = NULL;
2362         __u8 tos = RT_FL_TOS(fl4);
2363         unsigned int flags = 0;
2364         struct fib_result res;
2365         struct rtable *rth;
2366         __be32 orig_daddr;
2367         __be32 orig_saddr;
2368         int orig_oif;
2369
2370         res.fi          = NULL;
2371         res.table       = NULL;
2372 #ifdef CONFIG_IP_MULTIPLE_TABLES
2373         res.r           = NULL;
2374 #endif
2375
2376         orig_daddr = fl4->daddr;
2377         orig_saddr = fl4->saddr;
2378         orig_oif = fl4->flowi4_oif;
2379
2380         fl4->flowi4_iif = net->loopback_dev->ifindex;
2381         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2382         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2383                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2384
2385         rcu_read_lock();
2386         if (fl4->saddr) {
2387                 rth = ERR_PTR(-EINVAL);
2388                 if (ipv4_is_multicast(fl4->saddr) ||
2389                     ipv4_is_lbcast(fl4->saddr) ||
2390                     ipv4_is_zeronet(fl4->saddr))
2391                         goto out;
2392
2393                 /* I removed check for oif == dev_out->oif here.
2394                    It was wrong for two reasons:
2395                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2396                       is assigned to multiple interfaces.
2397                    2. Moreover, we are allowed to send packets with saddr
2398                       of another iface. --ANK
2399                  */
2400
2401                 if (fl4->flowi4_oif == 0 &&
2402                     (ipv4_is_multicast(fl4->daddr) ||
2403                      ipv4_is_lbcast(fl4->daddr))) {
2404                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2405                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2406                         if (dev_out == NULL)
2407                                 goto out;
2408
2409                         /* Special hack: user can direct multicasts
2410                            and limited broadcast via necessary interface
2411                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2412                            This hack is not just for fun, it allows
2413                            vic,vat and friends to work.
2414                            They bind socket to loopback, set ttl to zero
2415                            and expect that it will work.
2416                            From the viewpoint of routing cache they are broken,
2417                            because we are not allowed to build multicast path
2418                            with loopback source addr (look, routing cache
2419                            cannot know, that ttl is zero, so that packet
2420                            will not leave this host and route is valid).
2421                            Luckily, this hack is good workaround.
2422                          */
2423
2424                         fl4->flowi4_oif = dev_out->ifindex;
2425                         goto make_route;
2426                 }
2427
2428                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2429                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2430                         if (!__ip_dev_find(net, fl4->saddr, false))
2431                                 goto out;
2432                 }
2433         }
2434
2435
2436         if (fl4->flowi4_oif) {
2437                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2438                 rth = ERR_PTR(-ENODEV);
2439                 if (dev_out == NULL)
2440                         goto out;
2441
2442                 /* RACE: Check return value of inet_select_addr instead. */
2443                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2444                         rth = ERR_PTR(-ENETUNREACH);
2445                         goto out;
2446                 }
2447                 if (ipv4_is_local_multicast(fl4->daddr) ||
2448                     ipv4_is_lbcast(fl4->daddr)) {
2449                         if (!fl4->saddr)
2450                                 fl4->saddr = inet_select_addr(dev_out, 0,
2451                                                               RT_SCOPE_LINK);
2452                         goto make_route;
2453                 }
2454                 if (fl4->saddr) {
2455                         if (ipv4_is_multicast(fl4->daddr))
2456                                 fl4->saddr = inet_select_addr(dev_out, 0,
2457                                                               fl4->flowi4_scope);
2458                         else if (!fl4->daddr)
2459                                 fl4->saddr = inet_select_addr(dev_out, 0,
2460                                                               RT_SCOPE_HOST);
2461                 }
2462         }
2463
2464         if (!fl4->daddr) {
2465                 fl4->daddr = fl4->saddr;
2466                 if (!fl4->daddr)
2467                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2468                 dev_out = net->loopback_dev;
2469                 fl4->flowi4_oif = net->loopback_dev->ifindex;
2470                 res.type = RTN_LOCAL;
2471                 flags |= RTCF_LOCAL;
2472                 goto make_route;
2473         }
2474
2475         if (fib_lookup(net, fl4, &res)) {
2476                 res.fi = NULL;
2477                 res.table = NULL;
2478                 if (fl4->flowi4_oif) {
2479                         /* Apparently, routing tables are wrong. Assume,
2480                            that the destination is on link.
2481
2482                            WHY? DW.
2483                            Because we are allowed to send to iface
2484                            even if it has NO routes and NO assigned
2485                            addresses. When oif is specified, routing
2486                            tables are looked up with only one purpose:
2487                            to catch if destination is gatewayed, rather than
2488                            direct. Moreover, if MSG_DONTROUTE is set,
2489                            we send packet, ignoring both routing tables
2490                            and ifaddr state. --ANK
2491
2492
2493                            We could make it even if oif is unknown,
2494                            likely IPv6, but we do not.
2495                          */
2496
2497                         if (fl4->saddr == 0)
2498                                 fl4->saddr = inet_select_addr(dev_out, 0,
2499                                                               RT_SCOPE_LINK);
2500                         res.type = RTN_UNICAST;
2501                         goto make_route;
2502                 }
2503                 rth = ERR_PTR(-ENETUNREACH);
2504                 goto out;
2505         }
2506
2507         if (res.type == RTN_LOCAL) {
2508                 if (!fl4->saddr) {
2509                         if (res.fi->fib_prefsrc)
2510                                 fl4->saddr = res.fi->fib_prefsrc;
2511                         else
2512                                 fl4->saddr = fl4->daddr;
2513                 }
2514                 dev_out = net->loopback_dev;
2515                 fl4->flowi4_oif = dev_out->ifindex;
2516                 res.fi = NULL;
2517                 flags |= RTCF_LOCAL;
2518                 goto make_route;
2519         }
2520
2521 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2522         if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2523                 fib_select_multipath(&res);
2524         else
2525 #endif
2526         if (!res.prefixlen &&
2527             res.table->tb_num_default > 1 &&
2528             res.type == RTN_UNICAST && !fl4->flowi4_oif)
2529                 fib_select_default(&res);
2530
2531         if (!fl4->saddr)
2532                 fl4->saddr = FIB_RES_PREFSRC(net, res);
2533
2534         dev_out = FIB_RES_DEV(res);
2535         fl4->flowi4_oif = dev_out->ifindex;
2536
2537
2538 make_route:
2539         rth = __mkroute_output(&res, fl4, orig_daddr, orig_saddr, orig_oif,
2540                                tos, dev_out, flags);
2541         if (!IS_ERR(rth)) {
2542                 unsigned int hash;
2543
2544                 hash = rt_hash(orig_daddr, orig_saddr, orig_oif,
2545                                rt_genid(dev_net(dev_out)));
2546                 rth = rt_intern_hash(hash, rth, NULL, orig_oif);
2547         }
2548
2549 out:
2550         rcu_read_unlock();
2551         return rth;
2552 }
2553
2554 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
2555 {
2556         struct rtable *rth;
2557         unsigned int hash;
2558
2559         if (!rt_caching(net))
2560                 goto slow_output;
2561
2562         hash = rt_hash(flp4->daddr, flp4->saddr, flp4->flowi4_oif, rt_genid(net));
2563
2564         rcu_read_lock_bh();
2565         for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
2566                 rth = rcu_dereference_bh(rth->dst.rt_next)) {
2567                 if (rth->rt_key_dst == flp4->daddr &&
2568                     rth->rt_key_src == flp4->saddr &&
2569                     rt_is_output_route(rth) &&
2570                     rth->rt_oif == flp4->flowi4_oif &&
2571                     rth->rt_mark == flp4->flowi4_mark &&
2572                     !((rth->rt_key_tos ^ flp4->flowi4_tos) &
2573                             (IPTOS_RT_MASK | RTO_ONLINK)) &&
2574                     net_eq(dev_net(rth->dst.dev), net) &&
2575                     !rt_is_expired(rth)) {
2576                         dst_use(&rth->dst, jiffies);
2577                         RT_CACHE_STAT_INC(out_hit);
2578                         rcu_read_unlock_bh();
2579                         if (!flp4->saddr)
2580                                 flp4->saddr = rth->rt_src;
2581                         if (!flp4->daddr)
2582                                 flp4->daddr = rth->rt_dst;
2583                         return rth;
2584                 }
2585                 RT_CACHE_STAT_INC(out_hlist_search);
2586         }
2587         rcu_read_unlock_bh();
2588
2589 slow_output:
2590         return ip_route_output_slow(net, flp4);
2591 }
2592 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2593
2594 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2595 {
2596         return NULL;
2597 }
2598
2599 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2600 {
2601         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2602
2603         return mtu ? : dst->dev->mtu;
2604 }
2605
2606 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
2607 {
2608 }
2609
2610 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2611                                           unsigned long old)
2612 {
2613         return NULL;
2614 }
2615
2616 static struct dst_ops ipv4_dst_blackhole_ops = {
2617         .family                 =       AF_INET,
2618         .protocol               =       cpu_to_be16(ETH_P_IP),
2619         .destroy                =       ipv4_dst_destroy,
2620         .check                  =       ipv4_blackhole_dst_check,
2621         .mtu                    =       ipv4_blackhole_mtu,
2622         .default_advmss         =       ipv4_default_advmss,
2623         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2624         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2625         .neigh_lookup           =       ipv4_neigh_lookup,
2626 };
2627
2628 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2629 {
2630         struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);
2631         struct rtable *ort = (struct rtable *) dst_orig;
2632
2633         if (rt) {
2634                 struct dst_entry *new = &rt->dst;
2635
2636                 new->__use = 1;
2637                 new->input = dst_discard;
2638                 new->output = dst_discard;
2639
2640                 new->dev = ort->dst.dev;
2641                 if (new->dev)
2642                         dev_hold(new->dev);
2643
2644                 rt->rt_key_dst = ort->rt_key_dst;
2645                 rt->rt_key_src = ort->rt_key_src;
2646                 rt->rt_key_tos = ort->rt_key_tos;
2647                 rt->rt_route_iif = ort->rt_route_iif;
2648                 rt->rt_iif = ort->rt_iif;
2649                 rt->rt_oif = ort->rt_oif;
2650                 rt->rt_mark = ort->rt_mark;
2651                 rt->rt_pmtu = ort->rt_pmtu;
2652
2653                 rt->rt_genid = rt_genid(net);
2654                 rt->rt_flags = ort->rt_flags;
2655                 rt->rt_type = ort->rt_type;
2656                 rt->rt_dst = ort->rt_dst;
2657                 rt->rt_src = ort->rt_src;
2658                 rt->rt_gateway = ort->rt_gateway;
2659                 rt->fi = ort->fi;
2660                 if (rt->fi)
2661                         atomic_inc(&rt->fi->fib_clntref);
2662
2663                 dst_free(new);
2664         }
2665
2666         dst_release(dst_orig);
2667
2668         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2669 }
2670
2671 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2672                                     struct sock *sk)
2673 {
2674         struct rtable *rt = __ip_route_output_key(net, flp4);
2675
2676         if (IS_ERR(rt))
2677                 return rt;
2678
2679         if (flp4->flowi4_proto)
2680                 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2681                                                    flowi4_to_flowi(flp4),
2682                                                    sk, 0);
2683
2684         return rt;
2685 }
2686 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2687
2688 static int rt_fill_info(struct net *net,
2689                         struct sk_buff *skb, u32 pid, u32 seq, int event,
2690                         int nowait, unsigned int flags)
2691 {
2692         struct rtable *rt = skb_rtable(skb);
2693         struct rtmsg *r;
2694         struct nlmsghdr *nlh;
2695         unsigned long expires = 0;
2696         u32 error;
2697
2698         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2699         if (nlh == NULL)
2700                 return -EMSGSIZE;
2701
2702         r = nlmsg_data(nlh);
2703         r->rtm_family    = AF_INET;
2704         r->rtm_dst_len  = 32;
2705         r->rtm_src_len  = 0;
2706         r->rtm_tos      = rt->rt_key_tos;
2707         r->rtm_table    = RT_TABLE_MAIN;
2708         if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2709                 goto nla_put_failure;
2710         r->rtm_type     = rt->rt_type;
2711         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2712         r->rtm_protocol = RTPROT_UNSPEC;
2713         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2714         if (rt->rt_flags & RTCF_NOTIFY)
2715                 r->rtm_flags |= RTM_F_NOTIFY;
2716
2717         if (nla_put_be32(skb, RTA_DST, rt->rt_dst))
2718                 goto nla_put_failure;
2719         if (rt->rt_key_src) {
2720                 r->rtm_src_len = 32;
2721                 if (nla_put_be32(skb, RTA_SRC, rt->rt_key_src))
2722                         goto nla_put_failure;
2723         }
2724         if (rt->dst.dev &&
2725             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2726                 goto nla_put_failure;
2727 #ifdef CONFIG_IP_ROUTE_CLASSID
2728         if (rt->dst.tclassid &&
2729             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2730                 goto nla_put_failure;
2731 #endif
2732         if (!rt_is_input_route(rt) &&
2733             rt->rt_src != rt->rt_key_src) {
2734                 if (nla_put_be32(skb, RTA_PREFSRC, rt->rt_src))
2735                         goto nla_put_failure;
2736         }
2737         if (rt->rt_dst != rt->rt_gateway &&
2738             nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2739                 goto nla_put_failure;
2740
2741         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
2742                 goto nla_put_failure;
2743
2744         if (rt->rt_mark &&
2745             nla_put_be32(skb, RTA_MARK, rt->rt_mark))
2746                 goto nla_put_failure;
2747
2748         error = rt->dst.error;
2749         expires = rt->dst.expires;
2750         if (expires) {
2751                 if (time_before(jiffies, expires))
2752                         expires -= jiffies;
2753                 else
2754                         expires = 0;
2755         }
2756
2757         if (rt_is_input_route(rt)) {
2758 #ifdef CONFIG_IP_MROUTE
2759                 __be32 dst = rt->rt_dst;
2760
2761                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2762                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2763                         int err = ipmr_get_route(net, skb,
2764                                                  rt->rt_src, rt->rt_dst,
2765                                                  r, nowait);
2766                         if (err <= 0) {
2767                                 if (!nowait) {
2768                                         if (err == 0)
2769                                                 return 0;
2770                                         goto nla_put_failure;
2771                                 } else {
2772                                         if (err == -EMSGSIZE)
2773                                                 goto nla_put_failure;
2774                                         error = err;
2775                                 }
2776                         }
2777                 } else
2778 #endif
2779                         if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2780                                 goto nla_put_failure;
2781         }
2782
2783         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2784                 goto nla_put_failure;
2785
2786         return nlmsg_end(skb, nlh);
2787
2788 nla_put_failure:
2789         nlmsg_cancel(skb, nlh);
2790         return -EMSGSIZE;
2791 }
2792
2793 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2794 {
2795         struct net *net = sock_net(in_skb->sk);
2796         struct rtmsg *rtm;
2797         struct nlattr *tb[RTA_MAX+1];
2798         struct rtable *rt = NULL;
2799         __be32 dst = 0;
2800         __be32 src = 0;
2801         u32 iif;
2802         int err;
2803         int mark;
2804         struct sk_buff *skb;
2805
2806         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2807         if (err < 0)
2808                 goto errout;
2809
2810         rtm = nlmsg_data(nlh);
2811
2812         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2813         if (skb == NULL) {
2814                 err = -ENOBUFS;
2815                 goto errout;
2816         }
2817
2818         /* Reserve room for dummy headers, this skb can pass
2819            through good chunk of routing engine.
2820          */
2821         skb_reset_mac_header(skb);
2822         skb_reset_network_header(skb);
2823
2824         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2825         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2826         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2827
2828         src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2829         dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2830         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2831         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2832
2833         if (iif) {
2834                 struct net_device *dev;
2835
2836                 dev = __dev_get_by_index(net, iif);
2837                 if (dev == NULL) {
2838                         err = -ENODEV;
2839                         goto errout_free;
2840                 }
2841
2842                 skb->protocol   = htons(ETH_P_IP);
2843                 skb->dev        = dev;
2844                 skb->mark       = mark;
2845                 local_bh_disable();
2846                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2847                 local_bh_enable();
2848
2849                 rt = skb_rtable(skb);
2850                 if (err == 0 && rt->dst.error)
2851                         err = -rt->dst.error;
2852         } else {
2853                 struct flowi4 fl4 = {
2854                         .daddr = dst,
2855                         .saddr = src,
2856                         .flowi4_tos = rtm->rtm_tos,
2857                         .flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
2858                         .flowi4_mark = mark,
2859                 };
2860                 rt = ip_route_output_key(net, &fl4);
2861
2862                 err = 0;
2863                 if (IS_ERR(rt))
2864                         err = PTR_ERR(rt);
2865         }
2866
2867         if (err)
2868                 goto errout_free;
2869
2870         skb_dst_set(skb, &rt->dst);
2871         if (rtm->rtm_flags & RTM_F_NOTIFY)
2872                 rt->rt_flags |= RTCF_NOTIFY;
2873
2874         err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2875                            RTM_NEWROUTE, 0, 0);
2876         if (err <= 0)
2877                 goto errout_free;
2878
2879         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2880 errout:
2881         return err;
2882
2883 errout_free:
2884         kfree_skb(skb);
2885         goto errout;
2886 }
2887
2888 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
2889 {
2890         struct rtable *rt;
2891         int h, s_h;
2892         int idx, s_idx;
2893         struct net *net;
2894
2895         net = sock_net(skb->sk);
2896
2897         s_h = cb->args[0];
2898         if (s_h < 0)
2899                 s_h = 0;
2900         s_idx = idx = cb->args[1];
2901         for (h = s_h; h <= rt_hash_mask; h++, s_idx = 0) {
2902                 if (!rt_hash_table[h].chain)
2903                         continue;
2904                 rcu_read_lock_bh();
2905                 for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
2906                      rt = rcu_dereference_bh(rt->dst.rt_next), idx++) {
2907                         if (!net_eq(dev_net(rt->dst.dev), net) || idx < s_idx)
2908                                 continue;
2909                         if (rt_is_expired(rt))
2910                                 continue;
2911                         skb_dst_set_noref(skb, &rt->dst);
2912                         if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
2913                                          cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2914                                          1, NLM_F_MULTI) <= 0) {
2915                                 skb_dst_drop(skb);
2916                                 rcu_read_unlock_bh();
2917                                 goto done;
2918                         }
2919                         skb_dst_drop(skb);
2920                 }
2921                 rcu_read_unlock_bh();
2922         }
2923
2924 done:
2925         cb->args[0] = h;
2926         cb->args[1] = idx;
2927         return skb->len;
2928 }
2929
2930 void ip_rt_multicast_event(struct in_device *in_dev)
2931 {
2932         rt_cache_flush(dev_net(in_dev->dev), 0);
2933 }
2934
2935 #ifdef CONFIG_SYSCTL
2936 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2937                                         void __user *buffer,
2938                                         size_t *lenp, loff_t *ppos)
2939 {
2940         if (write) {
2941                 int flush_delay;
2942                 ctl_table ctl;
2943                 struct net *net;
2944
2945                 memcpy(&ctl, __ctl, sizeof(ctl));
2946                 ctl.data = &flush_delay;
2947                 proc_dointvec(&ctl, write, buffer, lenp, ppos);
2948
2949                 net = (struct net *)__ctl->extra1;
2950                 rt_cache_flush(net, flush_delay);
2951                 return 0;
2952         }
2953
2954         return -EINVAL;
2955 }
2956
2957 static ctl_table ipv4_route_table[] = {
2958         {
2959                 .procname       = "gc_thresh",
2960                 .data           = &ipv4_dst_ops.gc_thresh,
2961                 .maxlen         = sizeof(int),
2962                 .mode           = 0644,
2963                 .proc_handler   = proc_dointvec,
2964         },
2965         {
2966                 .procname       = "max_size",
2967                 .data           = &ip_rt_max_size,
2968                 .maxlen         = sizeof(int),
2969                 .mode           = 0644,
2970                 .proc_handler   = proc_dointvec,
2971         },
2972         {
2973                 /*  Deprecated. Use gc_min_interval_ms */
2974
2975                 .procname       = "gc_min_interval",
2976                 .data           = &ip_rt_gc_min_interval,
2977                 .maxlen         = sizeof(int),
2978                 .mode           = 0644,
2979                 .proc_handler   = proc_dointvec_jiffies,
2980         },
2981         {
2982                 .procname       = "gc_min_interval_ms",
2983                 .data           = &ip_rt_gc_min_interval,
2984                 .maxlen         = sizeof(int),
2985                 .mode           = 0644,
2986                 .proc_handler   = proc_dointvec_ms_jiffies,
2987         },
2988         {
2989                 .procname       = "gc_timeout",
2990                 .data           = &ip_rt_gc_timeout,
2991                 .maxlen         = sizeof(int),
2992                 .mode           = 0644,
2993                 .proc_handler   = proc_dointvec_jiffies,
2994         },
2995         {
2996                 .procname       = "gc_interval",
2997                 .data           = &ip_rt_gc_interval,
2998                 .maxlen         = sizeof(int),
2999                 .mode           = 0644,
3000                 .proc_handler   = proc_dointvec_jiffies,
3001         },
3002         {
3003                 .procname       = "redirect_load",
3004                 .data           = &ip_rt_redirect_load,
3005                 .maxlen         = sizeof(int),
3006                 .mode           = 0644,
3007                 .proc_handler   = proc_dointvec,
3008         },
3009         {
3010                 .procname       = "redirect_number",
3011                 .data           = &ip_rt_redirect_number,
3012                 .maxlen         = sizeof(int),
3013                 .mode           = 0644,
3014                 .proc_handler   = proc_dointvec,
3015         },
3016         {
3017                 .procname       = "redirect_silence",
3018                 .data           = &ip_rt_redirect_silence,
3019                 .maxlen         = sizeof(int),
3020                 .mode           = 0644,
3021                 .proc_handler   = proc_dointvec,
3022         },
3023         {
3024                 .procname       = "error_cost",
3025                 .data           = &ip_rt_error_cost,
3026                 .maxlen         = sizeof(int),
3027                 .mode           = 0644,
3028                 .proc_handler   = proc_dointvec,
3029         },
3030         {
3031                 .procname       = "error_burst",
3032                 .data           = &ip_rt_error_burst,
3033                 .maxlen         = sizeof(int),
3034                 .mode           = 0644,
3035                 .proc_handler   = proc_dointvec,
3036         },
3037         {
3038                 .procname       = "gc_elasticity",
3039                 .data           = &ip_rt_gc_elasticity,
3040                 .maxlen         = sizeof(int),
3041                 .mode           = 0644,
3042                 .proc_handler   = proc_dointvec,
3043         },
3044         {
3045                 .procname       = "mtu_expires",
3046                 .data           = &ip_rt_mtu_expires,
3047                 .maxlen         = sizeof(int),
3048                 .mode           = 0644,
3049                 .proc_handler   = proc_dointvec_jiffies,
3050         },
3051         {
3052                 .procname       = "min_pmtu",
3053                 .data           = &ip_rt_min_pmtu,
3054                 .maxlen         = sizeof(int),
3055                 .mode           = 0644,
3056                 .proc_handler   = proc_dointvec,
3057         },
3058         {
3059                 .procname       = "min_adv_mss",
3060                 .data           = &ip_rt_min_advmss,
3061                 .maxlen         = sizeof(int),
3062                 .mode           = 0644,
3063                 .proc_handler   = proc_dointvec,
3064         },
3065         { }
3066 };
3067
3068 static struct ctl_table ipv4_route_flush_table[] = {
3069         {
3070                 .procname       = "flush",
3071                 .maxlen         = sizeof(int),
3072                 .mode           = 0200,
3073                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3074         },
3075         { },
3076 };
3077
3078 static __net_init int sysctl_route_net_init(struct net *net)
3079 {
3080         struct ctl_table *tbl;
3081
3082         tbl = ipv4_route_flush_table;
3083         if (!net_eq(net, &init_net)) {
3084                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3085                 if (tbl == NULL)
3086                         goto err_dup;
3087         }
3088         tbl[0].extra1 = net;
3089
3090         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3091         if (net->ipv4.route_hdr == NULL)
3092                 goto err_reg;
3093         return 0;
3094
3095 err_reg:
3096         if (tbl != ipv4_route_flush_table)
3097                 kfree(tbl);
3098 err_dup:
3099         return -ENOMEM;
3100 }
3101
3102 static __net_exit void sysctl_route_net_exit(struct net *net)
3103 {
3104         struct ctl_table *tbl;
3105
3106         tbl = net->ipv4.route_hdr->ctl_table_arg;
3107         unregister_net_sysctl_table(net->ipv4.route_hdr);
3108         BUG_ON(tbl == ipv4_route_flush_table);
3109         kfree(tbl);
3110 }
3111
3112 static __net_initdata struct pernet_operations sysctl_route_ops = {
3113         .init = sysctl_route_net_init,
3114         .exit = sysctl_route_net_exit,
3115 };
3116 #endif
3117
3118 static __net_init int rt_genid_init(struct net *net)
3119 {
3120         get_random_bytes(&net->ipv4.rt_genid,
3121                          sizeof(net->ipv4.rt_genid));
3122         get_random_bytes(&net->ipv4.dev_addr_genid,
3123                          sizeof(net->ipv4.dev_addr_genid));
3124         return 0;
3125 }
3126
3127 static __net_initdata struct pernet_operations rt_genid_ops = {
3128         .init = rt_genid_init,
3129 };
3130
3131 static int __net_init ipv4_inetpeer_init(struct net *net)
3132 {
3133         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3134
3135         if (!bp)
3136                 return -ENOMEM;
3137         inet_peer_base_init(bp);
3138         net->ipv4.peers = bp;
3139         return 0;
3140 }
3141
3142 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3143 {
3144         struct inet_peer_base *bp = net->ipv4.peers;
3145
3146         net->ipv4.peers = NULL;
3147         inetpeer_invalidate_tree(bp);
3148         kfree(bp);
3149 }
3150
3151 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3152         .init   =       ipv4_inetpeer_init,
3153         .exit   =       ipv4_inetpeer_exit,
3154 };
3155
3156 #ifdef CONFIG_IP_ROUTE_CLASSID
3157 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3158 #endif /* CONFIG_IP_ROUTE_CLASSID */
3159
3160 static __initdata unsigned long rhash_entries;
3161 static int __init set_rhash_entries(char *str)
3162 {
3163         ssize_t ret;
3164
3165         if (!str)
3166                 return 0;
3167
3168         ret = kstrtoul(str, 0, &rhash_entries);
3169         if (ret)
3170                 return 0;
3171
3172         return 1;
3173 }
3174 __setup("rhash_entries=", set_rhash_entries);
3175
3176 int __init ip_rt_init(void)
3177 {
3178         int rc = 0;
3179
3180 #ifdef CONFIG_IP_ROUTE_CLASSID
3181         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3182         if (!ip_rt_acct)
3183                 panic("IP: failed to allocate ip_rt_acct\n");
3184 #endif
3185
3186         ipv4_dst_ops.kmem_cachep =
3187                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3188                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3189
3190         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3191
3192         if (dst_entries_init(&ipv4_dst_ops) < 0)
3193                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3194
3195         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3196                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3197
3198         rt_hash_table = (struct rt_hash_bucket *)
3199                 alloc_large_system_hash("IP route cache",
3200                                         sizeof(struct rt_hash_bucket),
3201                                         rhash_entries,
3202                                         (totalram_pages >= 128 * 1024) ?
3203                                         15 : 17,
3204                                         0,
3205                                         &rt_hash_log,
3206                                         &rt_hash_mask,
3207                                         0,
3208                                         rhash_entries ? 0 : 512 * 1024);
3209         memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
3210         rt_hash_lock_init();
3211
3212         ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
3213         ip_rt_max_size = (rt_hash_mask + 1) * 16;
3214
3215         devinet_init();
3216         ip_fib_init();
3217
3218         INIT_DELAYED_WORK_DEFERRABLE(&expires_work, rt_worker_func);
3219         expires_ljiffies = jiffies;
3220         schedule_delayed_work(&expires_work,
3221                 net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
3222
3223         if (ip_rt_proc_init())
3224                 pr_err("Unable to create route proc files\n");
3225 #ifdef CONFIG_XFRM
3226         xfrm_init();
3227         xfrm4_init(ip_rt_max_size);
3228 #endif
3229         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3230
3231 #ifdef CONFIG_SYSCTL
3232         register_pernet_subsys(&sysctl_route_ops);
3233 #endif
3234         register_pernet_subsys(&rt_genid_ops);
3235         register_pernet_subsys(&ipv4_inetpeer_ops);
3236         return rc;
3237 }
3238
3239 #ifdef CONFIG_SYSCTL
3240 /*
3241  * We really need to sanitize the damn ipv4 init order, then all
3242  * this nonsense will go away.
3243  */
3244 void __init ip_static_sysctl_init(void)
3245 {
3246         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3247 }
3248 #endif