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, <[email protected]>
  10  *              Alan Cox, <[email protected]>
  11  *              Linus Torvalds, <[email protected]>
  12  *              Alexey Kuznetsov, <[email protected]>
  13  *
  14  * Fixes:
  15  *              Alan Cox        :       Verify area fixes.
  16  *              Alan Cox        :       cli() protects routing changes
  17  *              Rui Oliveira    :       ICMP routing table updates
  18  *              ([email protected])      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/string.h>
  74 #include <linux/socket.h>
  75 #include <linux/sockios.h>
  76 #include <linux/errno.h>
  77 #include <linux/in.h>
  78 #include <linux/inet.h>
  79 #include <linux/netdevice.h>
  80 #include <linux/proc_fs.h>
  81 #include <linux/init.h>
  82 #include <linux/skbuff.h>
  83 #include <linux/inetdevice.h>
  84 #include <linux/igmp.h>
  85 #include <linux/pkt_sched.h>
  86 #include <linux/mroute.h>
  87 #include <linux/netfilter_ipv4.h>
  88 #include <linux/random.h>
  89 #include <linux/rcupdate.h>
  90 #include <linux/times.h>
  91 #include <linux/slab.h>
  92 #include <linux/jhash.h>
  93 #include <net/dst.h>
  94 #include <net/dst_metadata.h>
  95 #include <net/net_namespace.h>
  96 #include <net/protocol.h>
  97 #include <net/ip.h>
  98 #include <net/route.h>
  99 #include <net/inetpeer.h>
 100 #include <net/sock.h>
 101 #include <net/ip_fib.h>
 102 #include <net/arp.h>
 103 #include <net/tcp.h>
 104 #include <net/icmp.h>
 105 #include <net/xfrm.h>
 106 #include <net/lwtunnel.h>
 107 #include <net/netevent.h>
 108 #include <net/rtnetlink.h>
 109 #ifdef CONFIG_SYSCTL
 110 #include <linux/sysctl.h>
 111 #include <linux/kmemleak.h>
 112 #endif
 113 #include <net/secure_seq.h>
 114 #include <net/ip_tunnels.h>
 115 #include <net/l3mdev.h>
 116
 117 #define RT_FL_TOS(oldflp4) \
 118         ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
 119
 120 #define RT_GC_TIMEOUT (300*HZ)
 121
 122 static int ip_rt_max_size;
 123 static int ip_rt_redirect_number __read_mostly  = 9;
 124 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 126 static int ip_rt_error_cost __read_mostly       = HZ;
 127 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 128 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
 129 static int ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
 130 static int ip_rt_min_advmss __read_mostly       = 256;
 131
 132 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 133 /*
 134  *      Interface to generic destination cache.
 135  */
 136
 137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 138 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 139 static unsigned int      ipv4_mtu(const struct dst_entry *dst);
 140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
 141 static void              ipv4_link_failure(struct sk_buff *skb);
 142 static void              ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 143                                            struct sk_buff *skb, u32 mtu);
 144 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
 145                                         struct sk_buff *skb);
 146 static void             ipv4_dst_destroy(struct dst_entry *dst);
 147
 148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 149 {
 150         WARN_ON(1);
 151         return NULL;
 152 }
 153
 154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 155                                            struct sk_buff *skb,
 156                                            const void *daddr);
 157
 158 static struct dst_ops ipv4_dst_ops = {
 159         .family =               AF_INET,
 160         .check =                ipv4_dst_check,
 161         .default_advmss =       ipv4_default_advmss,
 162         .mtu =                  ipv4_mtu,
 163         .cow_metrics =          ipv4_cow_metrics,
 164         .destroy =              ipv4_dst_destroy,
 165         .negative_advice =      ipv4_negative_advice,
 166         .link_failure =         ipv4_link_failure,
 167         .update_pmtu =          ip_rt_update_pmtu,
 168         .redirect =             ip_do_redirect,
 169         .local_out =            __ip_local_out,
 170         .neigh_lookup =         ipv4_neigh_lookup,
 171 };
 172
 173 #define ECN_OR_COST(class)      TC_PRIO_##class
 174
 175 const __u8 ip_tos2prio[16] = {
 176         TC_PRIO_BESTEFFORT,
 177         ECN_OR_COST(BESTEFFORT),
 178         TC_PRIO_BESTEFFORT,
 179         ECN_OR_COST(BESTEFFORT),
 180         TC_PRIO_BULK,
 181         ECN_OR_COST(BULK),
 182         TC_PRIO_BULK,
 183         ECN_OR_COST(BULK),
 184         TC_PRIO_INTERACTIVE,
 185         ECN_OR_COST(INTERACTIVE),
 186         TC_PRIO_INTERACTIVE,
 187         ECN_OR_COST(INTERACTIVE),
 188         TC_PRIO_INTERACTIVE_BULK,
 189         ECN_OR_COST(INTERACTIVE_BULK),
 190         TC_PRIO_INTERACTIVE_BULK,
 191         ECN_OR_COST(INTERACTIVE_BULK)
 192 };
 193 EXPORT_SYMBOL(ip_tos2prio);
 194
 195 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 196 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
 197
 198 #ifdef CONFIG_PROC_FS
 199 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 200 {
 201         if (*pos)
 202                 return NULL;
 203         return SEQ_START_TOKEN;
 204 }
 205
 206 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 207 {
 208         ++*pos;
 209         return NULL;
 210 }
 211
 212 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 213 {
 214 }
 215
 216 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 217 {
 218         if (v == SEQ_START_TOKEN)
 219                 seq_printf(seq, "%-127s\n",
 220                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 221                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 222                            "HHUptod\tSpecDst");
 223         return 0;
 224 }
 225
 226 static const struct seq_operations rt_cache_seq_ops = {
 227         .start  = rt_cache_seq_start,
 228         .next   = rt_cache_seq_next,
 229         .stop   = rt_cache_seq_stop,
 230         .show   = rt_cache_seq_show,
 231 };
 232
 233 static int rt_cache_seq_open(struct inode *inode, struct file *file)
 234 {
 235         return seq_open(file, &rt_cache_seq_ops);
 236 }
 237
 238 static const struct file_operations rt_cache_seq_fops = {
 239         .owner   = THIS_MODULE,
 240         .open    = rt_cache_seq_open,
 241         .read    = seq_read,
 242         .llseek  = seq_lseek,
 243         .release = seq_release,
 244 };
 245
 246
 247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 248 {
 249         int cpu;
 250
 251         if (*pos == 0)
 252                 return SEQ_START_TOKEN;
 253
 254         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 255                 if (!cpu_possible(cpu))
 256                         continue;
 257                 *pos = cpu+1;
 258                 return &per_cpu(rt_cache_stat, cpu);
 259         }
 260         return NULL;
 261 }
 262
 263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 264 {
 265         int cpu;
 266
 267         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 268                 if (!cpu_possible(cpu))
 269                         continue;
 270                 *pos = cpu+1;
 271                 return &per_cpu(rt_cache_stat, cpu);
 272         }
 273         return NULL;
 274
 275 }
 276
 277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 278 {
 279
 280 }
 281
 282 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 283 {
 284         struct rt_cache_stat *st = v;
 285
 286         if (v == SEQ_START_TOKEN) {
 287                 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");
 288                 return 0;
 289         }
 290
 291         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 292                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
 293                    dst_entries_get_slow(&ipv4_dst_ops),
 294                    0, /* st->in_hit */
 295                    st->in_slow_tot,
 296                    st->in_slow_mc,
 297                    st->in_no_route,
 298                    st->in_brd,
 299                    st->in_martian_dst,
 300                    st->in_martian_src,
 301
 302                    0, /* st->out_hit */
 303                    st->out_slow_tot,
 304                    st->out_slow_mc,
 305
 306                    0, /* st->gc_total */
 307                    0, /* st->gc_ignored */
 308                    0, /* st->gc_goal_miss */
 309                    0, /* st->gc_dst_overflow */
 310                    0, /* st->in_hlist_search */
 311                    0  /* st->out_hlist_search */
 312                 );
 313         return 0;
 314 }
 315
 316 static const struct seq_operations rt_cpu_seq_ops = {
 317         .start  = rt_cpu_seq_start,
 318         .next   = rt_cpu_seq_next,
 319         .stop   = rt_cpu_seq_stop,
 320         .show   = rt_cpu_seq_show,
 321 };
 322
 323
 324 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 325 {
 326         return seq_open(file, &rt_cpu_seq_ops);
 327 }
 328
 329 static const struct file_operations rt_cpu_seq_fops = {
 330         .owner   = THIS_MODULE,
 331         .open    = rt_cpu_seq_open,
 332         .read    = seq_read,
 333         .llseek  = seq_lseek,
 334         .release = seq_release,
 335 };
 336
 337 #ifdef CONFIG_IP_ROUTE_CLASSID
 338 static int rt_acct_proc_show(struct seq_file *m, void *v)
 339 {
 340         struct ip_rt_acct *dst, *src;
 341         unsigned int i, j;
 342
 343         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 344         if (!dst)
 345                 return -ENOMEM;
 346
 347         for_each_possible_cpu(i) {
 348                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 349                 for (j = 0; j < 256; j++) {
 350                         dst[j].o_bytes   += src[j].o_bytes;
 351                         dst[j].o_packets += src[j].o_packets;
 352                         dst[j].i_bytes   += src[j].i_bytes;
 353                         dst[j].i_packets += src[j].i_packets;
 354                 }
 355         }
 356
 357         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 358         kfree(dst);
 359         return 0;
 360 }
 361
 362 static int rt_acct_proc_open(struct inode *inode, struct file *file)
 363 {
 364         return single_open(file, rt_acct_proc_show, NULL);
 365 }
 366
 367 static const struct file_operations rt_acct_proc_fops = {
 368         .owner          = THIS_MODULE,
 369         .open           = rt_acct_proc_open,
 370         .read           = seq_read,
 371         .llseek         = seq_lseek,
 372         .release        = single_release,
 373 };
 374 #endif
 375
 376 static int __net_init ip_rt_do_proc_init(struct net *net)
 377 {
 378         struct proc_dir_entry *pde;
 379
 380         pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
 381                           &rt_cache_seq_fops);
 382         if (!pde)
 383                 goto err1;
 384
 385         pde = proc_create("rt_cache", S_IRUGO,
 386                           net->proc_net_stat, &rt_cpu_seq_fops);
 387         if (!pde)
 388                 goto err2;
 389
 390 #ifdef CONFIG_IP_ROUTE_CLASSID
 391         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
 392         if (!pde)
 393                 goto err3;
 394 #endif
 395         return 0;
 396
 397 #ifdef CONFIG_IP_ROUTE_CLASSID
 398 err3:
 399         remove_proc_entry("rt_cache", net->proc_net_stat);
 400 #endif
 401 err2:
 402         remove_proc_entry("rt_cache", net->proc_net);
 403 err1:
 404         return -ENOMEM;
 405 }
 406
 407 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 408 {
 409         remove_proc_entry("rt_cache", net->proc_net_stat);
 410         remove_proc_entry("rt_cache", net->proc_net);
 411 #ifdef CONFIG_IP_ROUTE_CLASSID
 412         remove_proc_entry("rt_acct", net->proc_net);
 413 #endif
 414 }
 415
 416 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 417         .init = ip_rt_do_proc_init,
 418         .exit = ip_rt_do_proc_exit,
 419 };
 420
 421 static int __init ip_rt_proc_init(void)
 422 {
 423         return register_pernet_subsys(&ip_rt_proc_ops);
 424 }
 425
 426 #else
 427 static inline int ip_rt_proc_init(void)
 428 {
 429         return 0;
 430 }
 431 #endif /* CONFIG_PROC_FS */
 432
 433 static inline bool rt_is_expired(const struct rtable *rth)
 434 {
 435         return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
 436 }
 437
 438 void rt_cache_flush(struct net *net)
 439 {
 440         rt_genid_bump_ipv4(net);
 441 }
 442
 443 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 444                                            struct sk_buff *skb,
 445                                            const void *daddr)
 446 {
 447         struct net_device *dev = dst->dev;
 448         const __be32 *pkey = daddr;
 449         const struct rtable *rt;
 450         struct neighbour *n;
 451
 452         rt = (const struct rtable *) dst;
 453         if (rt->rt_gateway)
 454                 pkey = (const __be32 *) &rt->rt_gateway;
 455         else if (skb)
 456                 pkey = &ip_hdr(skb)->daddr;
 457
 458         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
 459         if (n)
 460                 return n;
 461         return neigh_create(&arp_tbl, pkey, dev);
 462 }
 463
 464 #define IP_IDENTS_SZ 2048u
 465
 466 static atomic_t *ip_idents __read_mostly;
 467 static u32 *ip_tstamps __read_mostly;
 468
 469 /* In order to protect privacy, we add a perturbation to identifiers
 470  * if one generator is seldom used. This makes hard for an attacker
 471  * to infer how many packets were sent between two points in time.
 472  */
 473 u32 ip_idents_reserve(u32 hash, int segs)
 474 {
 475         u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
 476         atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
 477         u32 old = ACCESS_ONCE(*p_tstamp);
 478         u32 now = (u32)jiffies;
 479         u32 delta = 0;
 480
 481         if (old != now && cmpxchg(p_tstamp, old, now) == old)
 482                 delta = prandom_u32_max(now - old);
 483
 484         return atomic_add_return(segs + delta, p_id) - segs;
 485 }
 486 EXPORT_SYMBOL(ip_idents_reserve);
 487
 488 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
 489 {
 490         static u32 ip_idents_hashrnd __read_mostly;
 491         u32 hash, id;
 492
 493         net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
 494
 495         hash = jhash_3words((__force u32)iph->daddr,
 496                             (__force u32)iph->saddr,
 497                             iph->protocol ^ net_hash_mix(net),
 498                             ip_idents_hashrnd);
 499         id = ip_idents_reserve(hash, segs);
 500         iph->id = htons(id);
 501 }
 502 EXPORT_SYMBOL(__ip_select_ident);
 503
 504 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
 505                              const struct iphdr *iph,
 506                              int oif, u8 tos,
 507                              u8 prot, u32 mark, int flow_flags)
 508 {
 509         if (sk) {
 510                 const struct inet_sock *inet = inet_sk(sk);
 511
 512                 oif = sk->sk_bound_dev_if;
 513                 mark = sk->sk_mark;
 514                 tos = RT_CONN_FLAGS(sk);
 515                 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
 516         }
 517         flowi4_init_output(fl4, oif, mark, tos,
 518                            RT_SCOPE_UNIVERSE, prot,
 519                            flow_flags,
 520                            iph->daddr, iph->saddr, 0, 0);
 521 }
 522
 523 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
 524                                const struct sock *sk)
 525 {
 526         const struct iphdr *iph = ip_hdr(skb);
 527         int oif = skb->dev->ifindex;
 528         u8 tos = RT_TOS(iph->tos);
 529         u8 prot = iph->protocol;
 530         u32 mark = skb->mark;
 531
 532         __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
 533 }
 534
 535 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
 536 {
 537         const struct inet_sock *inet = inet_sk(sk);
 538         const struct ip_options_rcu *inet_opt;
 539         __be32 daddr = inet->inet_daddr;
 540
 541         rcu_read_lock();
 542         inet_opt = rcu_dereference(inet->inet_opt);
 543         if (inet_opt && inet_opt->opt.srr)
 544                 daddr = inet_opt->opt.faddr;
 545         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
 546                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
 547                            inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
 548                            inet_sk_flowi_flags(sk),
 549                            daddr, inet->inet_saddr, 0, 0);
 550         rcu_read_unlock();
 551 }
 552
 553 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
 554                                  const struct sk_buff *skb)
 555 {
 556         if (skb)
 557                 build_skb_flow_key(fl4, skb, sk);
 558         else
 559                 build_sk_flow_key(fl4, sk);
 560 }
 561
 562 static inline void rt_free(struct rtable *rt)
 563 {
 564         call_rcu(&rt->dst.rcu_head, dst_rcu_free);
 565 }
 566
 567 static DEFINE_SPINLOCK(fnhe_lock);
 568
 569 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
 570 {
 571         struct rtable *rt;
 572
 573         rt = rcu_dereference(fnhe->fnhe_rth_input);
 574         if (rt) {
 575                 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
 576                 rt_free(rt);
 577         }
 578         rt = rcu_dereference(fnhe->fnhe_rth_output);
 579         if (rt) {
 580                 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
 581                 rt_free(rt);
 582         }
 583 }
 584
 585 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
 586 {
 587         struct fib_nh_exception *fnhe, *oldest;
 588
 589         oldest = rcu_dereference(hash->chain);
 590         for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
 591              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 592                 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
 593                         oldest = fnhe;
 594         }
 595         fnhe_flush_routes(oldest);
 596         return oldest;
 597 }
 598
 599 static inline u32 fnhe_hashfun(__be32 daddr)
 600 {
 601         static u32 fnhe_hashrnd __read_mostly;
 602         u32 hval;
 603
 604         net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
 605         hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
 606         return hash_32(hval, FNHE_HASH_SHIFT);
 607 }
 608
 609 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
 610 {
 611         rt->rt_pmtu = fnhe->fnhe_pmtu;
 612         rt->dst.expires = fnhe->fnhe_expires;
 613
 614         if (fnhe->fnhe_gw) {
 615                 rt->rt_flags |= RTCF_REDIRECTED;
 616                 rt->rt_gateway = fnhe->fnhe_gw;
 617                 rt->rt_uses_gateway = 1;
 618         }
 619 }
 620
 621 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
 622                                   u32 pmtu, unsigned long expires)
 623 {
 624         struct fnhe_hash_bucket *hash;
 625         struct fib_nh_exception *fnhe;
 626         struct rtable *rt;
 627         unsigned int i;
 628         int depth;
 629         u32 hval = fnhe_hashfun(daddr);
 630
 631         spin_lock_bh(&fnhe_lock);
 632
 633         hash = rcu_dereference(nh->nh_exceptions);
 634         if (!hash) {
 635                 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
 636                 if (!hash)
 637                         goto out_unlock;
 638                 rcu_assign_pointer(nh->nh_exceptions, hash);
 639         }
 640
 641         hash += hval;
 642
 643         depth = 0;
 644         for (fnhe = rcu_dereference(hash->chain); fnhe;
 645              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 646                 if (fnhe->fnhe_daddr == daddr)
 647                         break;
 648                 depth++;
 649         }
 650
 651         if (fnhe) {
 652                 if (gw)
 653                         fnhe->fnhe_gw = gw;
 654                 if (pmtu) {
 655                         fnhe->fnhe_pmtu = pmtu;
 656                         fnhe->fnhe_expires = max(1UL, expires);
 657                 }
 658                 /* Update all cached dsts too */
 659                 rt = rcu_dereference(fnhe->fnhe_rth_input);
 660                 if (rt)
 661                         fill_route_from_fnhe(rt, fnhe);
 662                 rt = rcu_dereference(fnhe->fnhe_rth_output);
 663                 if (rt)
 664                         fill_route_from_fnhe(rt, fnhe);
 665         } else {
 666                 if (depth > FNHE_RECLAIM_DEPTH)
 667                         fnhe = fnhe_oldest(hash);
 668                 else {
 669                         fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
 670                         if (!fnhe)
 671                                 goto out_unlock;
 672
 673                         fnhe->fnhe_next = hash->chain;
 674                         rcu_assign_pointer(hash->chain, fnhe);
 675                 }
 676                 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
 677                 fnhe->fnhe_daddr = daddr;
 678                 fnhe->fnhe_gw = gw;
 679                 fnhe->fnhe_pmtu = pmtu;
 680                 fnhe->fnhe_expires = expires;
 681
 682                 /* Exception created; mark the cached routes for the nexthop
 683                  * stale, so anyone caching it rechecks if this exception
 684                  * applies to them.
 685                  */
 686                 rt = rcu_dereference(nh->nh_rth_input);
 687                 if (rt)
 688                         rt->dst.obsolete = DST_OBSOLETE_KILL;
 689
 690                 for_each_possible_cpu(i) {
 691                         struct rtable __rcu **prt;
 692                         prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
 693                         rt = rcu_dereference(*prt);
 694                         if (rt)
 695                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 696                 }
 697         }
 698
 699         fnhe->fnhe_stamp = jiffies;
 700
 701 out_unlock:
 702         spin_unlock_bh(&fnhe_lock);
 703 }
 704
 705 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 706                              bool kill_route)
 707 {
 708         __be32 new_gw = icmp_hdr(skb)->un.gateway;
 709         __be32 old_gw = ip_hdr(skb)->saddr;
 710         struct net_device *dev = skb->dev;
 711         struct in_device *in_dev;
 712         struct fib_result res;
 713         struct neighbour *n;
 714         struct net *net;
 715
 716         switch (icmp_hdr(skb)->code & 7) {
 717         case ICMP_REDIR_NET:
 718         case ICMP_REDIR_NETTOS:
 719         case ICMP_REDIR_HOST:
 720         case ICMP_REDIR_HOSTTOS:
 721                 break;
 722
 723         default:
 724                 return;
 725         }
 726
 727         if (rt->rt_gateway != old_gw)
 728                 return;
 729
 730         in_dev = __in_dev_get_rcu(dev);
 731         if (!in_dev)
 732                 return;
 733
 734         net = dev_net(dev);
 735         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
 736             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
 737             ipv4_is_zeronet(new_gw))
 738                 goto reject_redirect;
 739
 740         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
 741                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
 742                         goto reject_redirect;
 743                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
 744                         goto reject_redirect;
 745         } else {
 746                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
 747                         goto reject_redirect;
 748         }
 749
 750         n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
 751         if (!IS_ERR(n)) {
 752                 if (!(n->nud_state & NUD_VALID)) {
 753                         neigh_event_send(n, NULL);
 754                 } else {
 755                         if (fib_lookup(net, fl4, &res, 0) == 0) {
 756                                 struct fib_nh *nh = &FIB_RES_NH(res);
 757
 758                                 update_or_create_fnhe(nh, fl4->daddr, new_gw,
 759                                                 0, jiffies + ip_rt_gc_timeout);
 760                         }
 761                         if (kill_route)
 762                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 763                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 764                 }
 765                 neigh_release(n);
 766         }
 767         return;
 768
 769 reject_redirect:
 770 #ifdef CONFIG_IP_ROUTE_VERBOSE
 771         if (IN_DEV_LOG_MARTIANS(in_dev)) {
 772                 const struct iphdr *iph = (const struct iphdr *) skb->data;
 773                 __be32 daddr = iph->daddr;
 774                 __be32 saddr = iph->saddr;
 775
 776                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
 777                                      "  Advised path = %pI4 -> %pI4\n",
 778                                      &old_gw, dev->name, &new_gw,
 779                                      &saddr, &daddr);
 780         }
 781 #endif
 782         ;
 783 }
 784
 785 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
 786 {
 787         struct rtable *rt;
 788         struct flowi4 fl4;
 789         const struct iphdr *iph = (const struct iphdr *) skb->data;
 790         int oif = skb->dev->ifindex;
 791         u8 tos = RT_TOS(iph->tos);
 792         u8 prot = iph->protocol;
 793         u32 mark = skb->mark;
 794
 795         rt = (struct rtable *) dst;
 796
 797         __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
 798         __ip_do_redirect(rt, skb, &fl4, true);
 799 }
 800
 801 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 802 {
 803         struct rtable *rt = (struct rtable *)dst;
 804         struct dst_entry *ret = dst;
 805
 806         if (rt) {
 807                 if (dst->obsolete > 0) {
 808                         ip_rt_put(rt);
 809                         ret = NULL;
 810                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
 811                            rt->dst.expires) {
 812                         ip_rt_put(rt);
 813                         ret = NULL;
 814                 }
 815         }
 816         return ret;
 817 }
 818
 819 /*
 820  * Algorithm:
 821  *      1. The first ip_rt_redirect_number redirects are sent
 822  *         with exponential backoff, then we stop sending them at all,
 823  *         assuming that the host ignores our redirects.
 824  *      2. If we did not see packets requiring redirects
 825  *         during ip_rt_redirect_silence, we assume that the host
 826  *         forgot redirected route and start to send redirects again.
 827  *
 828  * This algorithm is much cheaper and more intelligent than dumb load limiting
 829  * in icmp.c.
 830  *
 831  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 832  * and "frag. need" (breaks PMTU discovery) in icmp.c.
 833  */
 834
 835 void ip_rt_send_redirect(struct sk_buff *skb)
 836 {
 837         struct rtable *rt = skb_rtable(skb);
 838         struct in_device *in_dev;
 839         struct inet_peer *peer;
 840         struct net *net;
 841         int log_martians;
 842         int vif;
 843
 844         rcu_read_lock();
 845         in_dev = __in_dev_get_rcu(rt->dst.dev);
 846         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
 847                 rcu_read_unlock();
 848                 return;
 849         }
 850         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
 851         vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
 852         rcu_read_unlock();
 853
 854         net = dev_net(rt->dst.dev);
 855         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
 856         if (!peer) {
 857                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
 858                           rt_nexthop(rt, ip_hdr(skb)->daddr));
 859                 return;
 860         }
 861
 862         /* No redirected packets during ip_rt_redirect_silence;
 863          * reset the algorithm.
 864          */
 865         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
 866                 peer->rate_tokens = 0;
 867
 868         /* Too many ignored redirects; do not send anything
 869          * set dst.rate_last to the last seen redirected packet.
 870          */
 871         if (peer->rate_tokens >= ip_rt_redirect_number) {
 872                 peer->rate_last = jiffies;
 873                 goto out_put_peer;
 874         }
 875
 876         /* Check for load limit; set rate_last to the latest sent
 877          * redirect.
 878          */
 879         if (peer->rate_tokens == 0 ||
 880             time_after(jiffies,
 881                        (peer->rate_last +
 882                         (ip_rt_redirect_load << peer->rate_tokens)))) {
 883                 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
 884
 885                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 886                 peer->rate_last = jiffies;
 887                 ++peer->rate_tokens;
 888 #ifdef CONFIG_IP_ROUTE_VERBOSE
 889                 if (log_martians &&
 890                     peer->rate_tokens == ip_rt_redirect_number)
 891                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 892                                              &ip_hdr(skb)->saddr, inet_iif(skb),
 893                                              &ip_hdr(skb)->daddr, &gw);
 894 #endif
 895         }
 896 out_put_peer:
 897         inet_putpeer(peer);
 898 }
 899
 900 static int ip_error(struct sk_buff *skb)
 901 {
 902         struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
 903         struct rtable *rt = skb_rtable(skb);
 904         struct inet_peer *peer;
 905         unsigned long now;
 906         struct net *net;
 907         bool send;
 908         int code;
 909
 910         /* IP on this device is disabled. */
 911         if (!in_dev)
 912                 goto out;
 913
 914         net = dev_net(rt->dst.dev);
 915         if (!IN_DEV_FORWARD(in_dev)) {
 916                 switch (rt->dst.error) {
 917                 case EHOSTUNREACH:
 918                         __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
 919                         break;
 920
 921                 case ENETUNREACH:
 922                         __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 923                         break;
 924                 }
 925                 goto out;
 926         }
 927
 928         switch (rt->dst.error) {
 929         case EINVAL:
 930         default:
 931                 goto out;
 932         case EHOSTUNREACH:
 933                 code = ICMP_HOST_UNREACH;
 934                 break;
 935         case ENETUNREACH:
 936                 code = ICMP_NET_UNREACH;
 937                 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 938                 break;
 939         case EACCES:
 940                 code = ICMP_PKT_FILTERED;
 941                 break;
 942         }
 943
 944         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
 945                                l3mdev_master_ifindex(skb->dev), 1);
 946
 947         send = true;
 948         if (peer) {
 949                 now = jiffies;
 950                 peer->rate_tokens += now - peer->rate_last;
 951                 if (peer->rate_tokens > ip_rt_error_burst)
 952                         peer->rate_tokens = ip_rt_error_burst;
 953                 peer->rate_last = now;
 954                 if (peer->rate_tokens >= ip_rt_error_cost)
 955                         peer->rate_tokens -= ip_rt_error_cost;
 956                 else
 957                         send = false;
 958                 inet_putpeer(peer);
 959         }
 960         if (send)
 961                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
 962
 963 out:    kfree_skb(skb);
 964         return 0;
 965 }
 966
 967 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 968 {
 969         struct dst_entry *dst = &rt->dst;
 970         struct fib_result res;
 971
 972         if (dst_metric_locked(dst, RTAX_MTU))
 973                 return;
 974
 975         if (ipv4_mtu(dst) < mtu)
 976                 return;
 977
 978         if (mtu < ip_rt_min_pmtu)
 979                 mtu = ip_rt_min_pmtu;
 980
 981         if (rt->rt_pmtu == mtu &&
 982             time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
 983                 return;
 984
 985         rcu_read_lock();
 986         if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
 987                 struct fib_nh *nh = &FIB_RES_NH(res);
 988
 989                 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
 990                                       jiffies + ip_rt_mtu_expires);
 991         }
 992         rcu_read_unlock();
 993 }
 994
 995 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 996                               struct sk_buff *skb, u32 mtu)
 997 {
 998         struct rtable *rt = (struct rtable *) dst;
 999         struct flowi4 fl4;
1000
1001         ip_rt_build_flow_key(&fl4, sk, skb);
1002         __ip_rt_update_pmtu(rt, &fl4, mtu);
1003 }
1004
1005 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1006                       int oif, u32 mark, u8 protocol, int flow_flags)
1007 {
1008         const struct iphdr *iph = (const struct iphdr *) skb->data;
1009         struct flowi4 fl4;
1010         struct rtable *rt;
1011
1012         if (!mark)
1013                 mark = IP4_REPLY_MARK(net, skb->mark);
1014
1015         __build_flow_key(&fl4, NULL, iph, oif,
1016                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1017         rt = __ip_route_output_key(net, &fl4);
1018         if (!IS_ERR(rt)) {
1019                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1020                 ip_rt_put(rt);
1021         }
1022 }
1023 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1024
1025 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1026 {
1027         const struct iphdr *iph = (const struct iphdr *) skb->data;
1028         struct flowi4 fl4;
1029         struct rtable *rt;
1030
1031         __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1032
1033         if (!fl4.flowi4_mark)
1034                 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1035
1036         rt = __ip_route_output_key(sock_net(sk), &fl4);
1037         if (!IS_ERR(rt)) {
1038                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1039                 ip_rt_put(rt);
1040         }
1041 }
1042
1043 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1044 {
1045         const struct iphdr *iph = (const struct iphdr *) skb->data;
1046         struct flowi4 fl4;
1047         struct rtable *rt;
1048         struct dst_entry *odst = NULL;
1049         bool new = false;
1050
1051         bh_lock_sock(sk);
1052
1053         if (!ip_sk_accept_pmtu(sk))
1054                 goto out;
1055
1056         odst = sk_dst_get(sk);
1057
1058         if (sock_owned_by_user(sk) || !odst) {
1059                 __ipv4_sk_update_pmtu(skb, sk, mtu);
1060                 goto out;
1061         }
1062
1063         __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1064
1065         rt = (struct rtable *)odst;
1066         if (odst->obsolete && !odst->ops->check(odst, 0)) {
1067                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1068                 if (IS_ERR(rt))
1069                         goto out;
1070
1071                 new = true;
1072         }
1073
1074         __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1075
1076         if (!dst_check(&rt->dst, 0)) {
1077                 if (new)
1078                         dst_release(&rt->dst);
1079
1080                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1081                 if (IS_ERR(rt))
1082                         goto out;
1083
1084                 new = true;
1085         }
1086
1087         if (new)
1088                 sk_dst_set(sk, &rt->dst);
1089
1090 out:
1091         bh_unlock_sock(sk);
1092         dst_release(odst);
1093 }
1094 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1095
1096 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1097                    int oif, u32 mark, u8 protocol, int flow_flags)
1098 {
1099         const struct iphdr *iph = (const struct iphdr *) skb->data;
1100         struct flowi4 fl4;
1101         struct rtable *rt;
1102
1103         __build_flow_key(&fl4, NULL, iph, oif,
1104                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1105         rt = __ip_route_output_key(net, &fl4);
1106         if (!IS_ERR(rt)) {
1107                 __ip_do_redirect(rt, skb, &fl4, false);
1108                 ip_rt_put(rt);
1109         }
1110 }
1111 EXPORT_SYMBOL_GPL(ipv4_redirect);
1112
1113 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1114 {
1115         const struct iphdr *iph = (const struct iphdr *) skb->data;
1116         struct flowi4 fl4;
1117         struct rtable *rt;
1118
1119         __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1120         rt = __ip_route_output_key(sock_net(sk), &fl4);
1121         if (!IS_ERR(rt)) {
1122                 __ip_do_redirect(rt, skb, &fl4, false);
1123                 ip_rt_put(rt);
1124         }
1125 }
1126 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1127
1128 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1129 {
1130         struct rtable *rt = (struct rtable *) dst;
1131
1132         /* All IPV4 dsts are created with ->obsolete set to the value
1133          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1134          * into this function always.
1135          *
1136          * When a PMTU/redirect information update invalidates a route,
1137          * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1138          * DST_OBSOLETE_DEAD by dst_free().
1139          */
1140         if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1141                 return NULL;
1142         return dst;
1143 }
1144
1145 static void ipv4_link_failure(struct sk_buff *skb)
1146 {
1147         struct rtable *rt;
1148
1149         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1150
1151         rt = skb_rtable(skb);
1152         if (rt)
1153                 dst_set_expires(&rt->dst, 0);
1154 }
1155
1156 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1157 {
1158         pr_debug("%s: %pI4 -> %pI4, %s\n",
1159                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1160                  skb->dev ? skb->dev->name : "?");
1161         kfree_skb(skb);
1162         WARN_ON(1);
1163         return 0;
1164 }
1165
1166 /*
1167    We do not cache source address of outgoing interface,
1168    because it is used only by IP RR, TS and SRR options,
1169    so that it out of fast path.
1170
1171    BTW remember: "addr" is allowed to be not aligned
1172    in IP options!
1173  */
1174
1175 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1176 {
1177         __be32 src;
1178
1179         if (rt_is_output_route(rt))
1180                 src = ip_hdr(skb)->saddr;
1181         else {
1182                 struct fib_result res;
1183                 struct flowi4 fl4;
1184                 struct iphdr *iph;
1185
1186                 iph = ip_hdr(skb);
1187
1188                 memset(&fl4, 0, sizeof(fl4));
1189                 fl4.daddr = iph->daddr;
1190                 fl4.saddr = iph->saddr;
1191                 fl4.flowi4_tos = RT_TOS(iph->tos);
1192                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1193                 fl4.flowi4_iif = skb->dev->ifindex;
1194                 fl4.flowi4_mark = skb->mark;
1195
1196                 rcu_read_lock();
1197                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1198                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1199                 else
1200                         src = inet_select_addr(rt->dst.dev,
1201                                                rt_nexthop(rt, iph->daddr),
1202                                                RT_SCOPE_UNIVERSE);
1203                 rcu_read_unlock();
1204         }
1205         memcpy(addr, &src, 4);
1206 }
1207
1208 #ifdef CONFIG_IP_ROUTE_CLASSID
1209 static void set_class_tag(struct rtable *rt, u32 tag)
1210 {
1211         if (!(rt->dst.tclassid & 0xFFFF))
1212                 rt->dst.tclassid |= tag & 0xFFFF;
1213         if (!(rt->dst.tclassid & 0xFFFF0000))
1214                 rt->dst.tclassid |= tag & 0xFFFF0000;
1215 }
1216 #endif
1217
1218 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1219 {
1220         unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1221
1222         if (advmss == 0) {
1223                 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1224                                ip_rt_min_advmss);
1225                 if (advmss > 65535 - 40)
1226                         advmss = 65535 - 40;
1227         }
1228         return advmss;
1229 }
1230
1231 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1232 {
1233         const struct rtable *rt = (const struct rtable *) dst;
1234         unsigned int mtu = rt->rt_pmtu;
1235
1236         if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1237                 mtu = dst_metric_raw(dst, RTAX_MTU);
1238
1239         if (mtu)
1240                 return mtu;
1241
1242         mtu = dst->dev->mtu;
1243
1244         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1245                 if (rt->rt_uses_gateway && mtu > 576)
1246                         mtu = 576;
1247         }
1248
1249         mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1250
1251         return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1252 }
1253
1254 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1255 {
1256         struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1257         struct fib_nh_exception *fnhe;
1258         u32 hval;
1259
1260         if (!hash)
1261                 return NULL;
1262
1263         hval = fnhe_hashfun(daddr);
1264
1265         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1266              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1267                 if (fnhe->fnhe_daddr == daddr)
1268                         return fnhe;
1269         }
1270         return NULL;
1271 }
1272
1273 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1274                               __be32 daddr)
1275 {
1276         bool ret = false;
1277
1278         spin_lock_bh(&fnhe_lock);
1279
1280         if (daddr == fnhe->fnhe_daddr) {
1281                 struct rtable __rcu **porig;
1282                 struct rtable *orig;
1283                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1284
1285                 if (rt_is_input_route(rt))
1286                         porig = &fnhe->fnhe_rth_input;
1287                 else
1288                         porig = &fnhe->fnhe_rth_output;
1289                 orig = rcu_dereference(*porig);
1290
1291                 if (fnhe->fnhe_genid != genid) {
1292                         fnhe->fnhe_genid = genid;
1293                         fnhe->fnhe_gw = 0;
1294                         fnhe->fnhe_pmtu = 0;
1295                         fnhe->fnhe_expires = 0;
1296                         fnhe_flush_routes(fnhe);
1297                         orig = NULL;
1298                 }
1299                 fill_route_from_fnhe(rt, fnhe);
1300                 if (!rt->rt_gateway)
1301                         rt->rt_gateway = daddr;
1302
1303                 if (!(rt->dst.flags & DST_NOCACHE)) {
1304                         rcu_assign_pointer(*porig, rt);
1305                         if (orig)
1306                                 rt_free(orig);
1307                         ret = true;
1308                 }
1309
1310                 fnhe->fnhe_stamp = jiffies;
1311         }
1312         spin_unlock_bh(&fnhe_lock);
1313
1314         return ret;
1315 }
1316
1317 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1318 {
1319         struct rtable *orig, *prev, **p;
1320         bool ret = true;
1321
1322         if (rt_is_input_route(rt)) {
1323                 p = (struct rtable **)&nh->nh_rth_input;
1324         } else {
1325                 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1326         }
1327         orig = *p;
1328
1329         prev = cmpxchg(p, orig, rt);
1330         if (prev == orig) {
1331                 if (orig)
1332                         rt_free(orig);
1333         } else
1334                 ret = false;
1335
1336         return ret;
1337 }
1338
1339 struct uncached_list {
1340         spinlock_t              lock;
1341         struct list_head        head;
1342 };
1343
1344 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1345
1346 static void rt_add_uncached_list(struct rtable *rt)
1347 {
1348         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1349
1350         rt->rt_uncached_list = ul;
1351
1352         spin_lock_bh(&ul->lock);
1353         list_add_tail(&rt->rt_uncached, &ul->head);
1354         spin_unlock_bh(&ul->lock);
1355 }
1356
1357 static void ipv4_dst_destroy(struct dst_entry *dst)
1358 {
1359         struct rtable *rt = (struct rtable *) dst;
1360
1361         if (!list_empty(&rt->rt_uncached)) {
1362                 struct uncached_list *ul = rt->rt_uncached_list;
1363
1364                 spin_lock_bh(&ul->lock);
1365                 list_del(&rt->rt_uncached);
1366                 spin_unlock_bh(&ul->lock);
1367         }
1368 }
1369
1370 void rt_flush_dev(struct net_device *dev)
1371 {
1372         struct net *net = dev_net(dev);
1373         struct rtable *rt;
1374         int cpu;
1375
1376         for_each_possible_cpu(cpu) {
1377                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1378
1379                 spin_lock_bh(&ul->lock);
1380                 list_for_each_entry(rt, &ul->head, rt_uncached) {
1381                         if (rt->dst.dev != dev)
1382                                 continue;
1383                         rt->dst.dev = net->loopback_dev;
1384                         dev_hold(rt->dst.dev);
1385                         dev_put(dev);
1386                 }
1387                 spin_unlock_bh(&ul->lock);
1388         }
1389 }
1390
1391 static bool rt_cache_valid(const struct rtable *rt)
1392 {
1393         return  rt &&
1394                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1395                 !rt_is_expired(rt);
1396 }
1397
1398 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1399                            const struct fib_result *res,
1400                            struct fib_nh_exception *fnhe,
1401                            struct fib_info *fi, u16 type, u32 itag)
1402 {
1403         bool cached = false;
1404
1405         if (fi) {
1406                 struct fib_nh *nh = &FIB_RES_NH(*res);
1407
1408                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1409                         rt->rt_gateway = nh->nh_gw;
1410                         rt->rt_uses_gateway = 1;
1411                 }
1412                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1413 #ifdef CONFIG_IP_ROUTE_CLASSID
1414                 rt->dst.tclassid = nh->nh_tclassid;
1415 #endif
1416                 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1417                 if (unlikely(fnhe))
1418                         cached = rt_bind_exception(rt, fnhe, daddr);
1419                 else if (!(rt->dst.flags & DST_NOCACHE))
1420                         cached = rt_cache_route(nh, rt);
1421                 if (unlikely(!cached)) {
1422                         /* Routes we intend to cache in nexthop exception or
1423                          * FIB nexthop have the DST_NOCACHE bit clear.
1424                          * However, if we are unsuccessful at storing this
1425                          * route into the cache we really need to set it.
1426                          */
1427                         rt->dst.flags |= DST_NOCACHE;
1428                         if (!rt->rt_gateway)
1429                                 rt->rt_gateway = daddr;
1430                         rt_add_uncached_list(rt);
1431                 }
1432         } else
1433                 rt_add_uncached_list(rt);
1434
1435 #ifdef CONFIG_IP_ROUTE_CLASSID
1436 #ifdef CONFIG_IP_MULTIPLE_TABLES
1437         set_class_tag(rt, res->tclassid);
1438 #endif
1439         set_class_tag(rt, itag);
1440 #endif
1441 }
1442
1443 struct rtable *rt_dst_alloc(struct net_device *dev,
1444                             unsigned int flags, u16 type,
1445                             bool nopolicy, bool noxfrm, bool will_cache)
1446 {
1447         struct rtable *rt;
1448
1449         rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1450                        (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1451                        (nopolicy ? DST_NOPOLICY : 0) |
1452                        (noxfrm ? DST_NOXFRM : 0));
1453
1454         if (rt) {
1455                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1456                 rt->rt_flags = flags;
1457                 rt->rt_type = type;
1458                 rt->rt_is_input = 0;
1459                 rt->rt_iif = 0;
1460                 rt->rt_pmtu = 0;
1461                 rt->rt_gateway = 0;
1462                 rt->rt_uses_gateway = 0;
1463                 rt->rt_table_id = 0;
1464                 INIT_LIST_HEAD(&rt->rt_uncached);
1465
1466                 rt->dst.output = ip_output;
1467                 if (flags & RTCF_LOCAL)
1468                         rt->dst.input = ip_local_deliver;
1469         }
1470
1471         return rt;
1472 }
1473 EXPORT_SYMBOL(rt_dst_alloc);
1474
1475 /* called in rcu_read_lock() section */
1476 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1477                                 u8 tos, struct net_device *dev, int our)
1478 {
1479         struct rtable *rth;
1480         struct in_device *in_dev = __in_dev_get_rcu(dev);
1481         unsigned int flags = RTCF_MULTICAST;
1482         u32 itag = 0;
1483         int err;
1484
1485         /* Primary sanity checks. */
1486
1487         if (!in_dev)
1488                 return -EINVAL;
1489
1490         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1491             skb->protocol != htons(ETH_P_IP))
1492                 goto e_inval;
1493
1494         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1495                 goto e_inval;
1496
1497         if (ipv4_is_zeronet(saddr)) {
1498                 if (!ipv4_is_local_multicast(daddr))
1499                         goto e_inval;
1500         } else {
1501                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1502                                           in_dev, &itag);
1503                 if (err < 0)
1504                         goto e_err;
1505         }
1506         if (our)
1507                 flags |= RTCF_LOCAL;
1508
1509         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1510                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1511         if (!rth)
1512                 goto e_nobufs;
1513
1514 #ifdef CONFIG_IP_ROUTE_CLASSID
1515         rth->dst.tclassid = itag;
1516 #endif
1517         rth->dst.output = ip_rt_bug;
1518         rth->rt_is_input= 1;
1519
1520 #ifdef CONFIG_IP_MROUTE
1521         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1522                 rth->dst.input = ip_mr_input;
1523 #endif
1524         RT_CACHE_STAT_INC(in_slow_mc);
1525
1526         skb_dst_set(skb, &rth->dst);
1527         return 0;
1528
1529 e_nobufs:
1530         return -ENOBUFS;
1531 e_inval:
1532         return -EINVAL;
1533 e_err:
1534         return err;
1535 }
1536
1537
1538 static void ip_handle_martian_source(struct net_device *dev,
1539                                      struct in_device *in_dev,
1540                                      struct sk_buff *skb,
1541                                      __be32 daddr,
1542                                      __be32 saddr)
1543 {
1544         RT_CACHE_STAT_INC(in_martian_src);
1545 #ifdef CONFIG_IP_ROUTE_VERBOSE
1546         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1547                 /*
1548                  *      RFC1812 recommendation, if source is martian,
1549                  *      the only hint is MAC header.
1550                  */
1551                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1552                         &daddr, &saddr, dev->name);
1553                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1554                         print_hex_dump(KERN_WARNING, "ll header: ",
1555                                        DUMP_PREFIX_OFFSET, 16, 1,
1556                                        skb_mac_header(skb),
1557                                        dev->hard_header_len, true);
1558                 }
1559         }
1560 #endif
1561 }
1562
1563 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1564 {
1565         struct fnhe_hash_bucket *hash;
1566         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1567         u32 hval = fnhe_hashfun(daddr);
1568
1569         spin_lock_bh(&fnhe_lock);
1570
1571         hash = rcu_dereference_protected(nh->nh_exceptions,
1572                                          lockdep_is_held(&fnhe_lock));
1573         hash += hval;
1574
1575         fnhe_p = &hash->chain;
1576         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1577         while (fnhe) {
1578                 if (fnhe->fnhe_daddr == daddr) {
1579                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1580                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1581                         fnhe_flush_routes(fnhe);
1582                         kfree_rcu(fnhe, rcu);
1583                         break;
1584                 }
1585                 fnhe_p = &fnhe->fnhe_next;
1586                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1587                                                  lockdep_is_held(&fnhe_lock));
1588         }
1589
1590         spin_unlock_bh(&fnhe_lock);
1591 }
1592
1593 /* called in rcu_read_lock() section */
1594 static int __mkroute_input(struct sk_buff *skb,
1595                            const struct fib_result *res,
1596                            struct in_device *in_dev,
1597                            __be32 daddr, __be32 saddr, u32 tos)
1598 {
1599         struct fib_nh_exception *fnhe;
1600         struct rtable *rth;
1601         int err;
1602         struct in_device *out_dev;
1603         bool do_cache;
1604         u32 itag = 0;
1605
1606         /* get a working reference to the output device */
1607         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1608         if (!out_dev) {
1609                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1610                 return -EINVAL;
1611         }
1612
1613         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1614                                   in_dev->dev, in_dev, &itag);
1615         if (err < 0) {
1616                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1617                                          saddr);
1618
1619                 goto cleanup;
1620         }
1621
1622         do_cache = res->fi && !itag;
1623         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1624             skb->protocol == htons(ETH_P_IP) &&
1625             (IN_DEV_SHARED_MEDIA(out_dev) ||
1626              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1627                 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1628
1629         if (skb->protocol != htons(ETH_P_IP)) {
1630                 /* Not IP (i.e. ARP). Do not create route, if it is
1631                  * invalid for proxy arp. DNAT routes are always valid.
1632                  *
1633                  * Proxy arp feature have been extended to allow, ARP
1634                  * replies back to the same interface, to support
1635                  * Private VLAN switch technologies. See arp.c.
1636                  */
1637                 if (out_dev == in_dev &&
1638                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1639                         err = -EINVAL;
1640                         goto cleanup;
1641                 }
1642         }
1643
1644         fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1645         if (do_cache) {
1646                 if (fnhe) {
1647                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1648                         if (rth && rth->dst.expires &&
1649                             time_after(jiffies, rth->dst.expires)) {
1650                                 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1651                                 fnhe = NULL;
1652                         } else {
1653                                 goto rt_cache;
1654                         }
1655                 }
1656
1657                 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1658
1659 rt_cache:
1660                 if (rt_cache_valid(rth)) {
1661                         skb_dst_set_noref(skb, &rth->dst);
1662                         goto out;
1663                 }
1664         }
1665
1666         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1667                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1668                            IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1669         if (!rth) {
1670                 err = -ENOBUFS;
1671                 goto cleanup;
1672         }
1673
1674         rth->rt_is_input = 1;
1675         if (res->table)
1676                 rth->rt_table_id = res->table->tb_id;
1677         RT_CACHE_STAT_INC(in_slow_tot);
1678
1679         rth->dst.input = ip_forward;
1680
1681         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1682         if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1683                 rth->dst.lwtstate->orig_output = rth->dst.output;
1684                 rth->dst.output = lwtunnel_output;
1685         }
1686         if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1687                 rth->dst.lwtstate->orig_input = rth->dst.input;
1688                 rth->dst.input = lwtunnel_input;
1689         }
1690         skb_dst_set(skb, &rth->dst);
1691 out:
1692         err = 0;
1693  cleanup:
1694         return err;
1695 }
1696
1697 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1698
1699 /* To make ICMP packets follow the right flow, the multipath hash is
1700  * calculated from the inner IP addresses in reverse order.
1701  */
1702 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1703 {
1704         const struct iphdr *outer_iph = ip_hdr(skb);
1705         struct icmphdr _icmph;
1706         const struct icmphdr *icmph;
1707         struct iphdr _inner_iph;
1708         const struct iphdr *inner_iph;
1709
1710         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1711                 goto standard_hash;
1712
1713         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1714                                    &_icmph);
1715         if (!icmph)
1716                 goto standard_hash;
1717
1718         if (icmph->type != ICMP_DEST_UNREACH &&
1719             icmph->type != ICMP_REDIRECT &&
1720             icmph->type != ICMP_TIME_EXCEEDED &&
1721             icmph->type != ICMP_PARAMETERPROB) {
1722                 goto standard_hash;
1723         }
1724
1725         inner_iph = skb_header_pointer(skb,
1726                                        outer_iph->ihl * 4 + sizeof(_icmph),
1727                                        sizeof(_inner_iph), &_inner_iph);
1728         if (!inner_iph)
1729                 goto standard_hash;
1730
1731         return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1732
1733 standard_hash:
1734         return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1735 }
1736
1737 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1738
1739 static int ip_mkroute_input(struct sk_buff *skb,
1740                             struct fib_result *res,
1741                             const struct flowi4 *fl4,
1742                             struct in_device *in_dev,
1743                             __be32 daddr, __be32 saddr, u32 tos)
1744 {
1745 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1746         if (res->fi && res->fi->fib_nhs > 1) {
1747                 int h;
1748
1749                 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1750                         h = ip_multipath_icmp_hash(skb);
1751                 else
1752                         h = fib_multipath_hash(saddr, daddr);
1753                 fib_select_multipath(res, h);
1754         }
1755 #endif
1756
1757         /* create a routing cache entry */
1758         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1759 }
1760
1761 /*
1762  *      NOTE. We drop all the packets that has local source
1763  *      addresses, because every properly looped back packet
1764  *      must have correct destination already attached by output routine.
1765  *
1766  *      Such approach solves two big problems:
1767  *      1. Not simplex devices are handled properly.
1768  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1769  *      called with rcu_read_lock()
1770  */
1771
1772 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1773                                u8 tos, struct net_device *dev)
1774 {
1775         struct fib_result res;
1776         struct in_device *in_dev = __in_dev_get_rcu(dev);
1777         struct ip_tunnel_info *tun_info;
1778         struct flowi4   fl4;
1779         unsigned int    flags = 0;
1780         u32             itag = 0;
1781         struct rtable   *rth;
1782         int             err = -EINVAL;
1783         struct net    *net = dev_net(dev);
1784         bool do_cache;
1785
1786         /* IP on this device is disabled. */
1787
1788         if (!in_dev)
1789                 goto out;
1790
1791         /* Check for the most weird martians, which can be not detected
1792            by fib_lookup.
1793          */
1794
1795         tun_info = skb_tunnel_info(skb);
1796         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1797                 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1798         else
1799                 fl4.flowi4_tun_key.tun_id = 0;
1800         skb_dst_drop(skb);
1801
1802         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1803                 goto martian_source;
1804
1805         res.fi = NULL;
1806         res.table = NULL;
1807         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1808                 goto brd_input;
1809
1810         /* Accept zero addresses only to limited broadcast;
1811          * I even do not know to fix it or not. Waiting for complains :-)
1812          */
1813         if (ipv4_is_zeronet(saddr))
1814                 goto martian_source;
1815
1816         if (ipv4_is_zeronet(daddr))
1817                 goto martian_destination;
1818
1819         /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1820          * and call it once if daddr or/and saddr are loopback addresses
1821          */
1822         if (ipv4_is_loopback(daddr)) {
1823                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1824                         goto martian_destination;
1825         } else if (ipv4_is_loopback(saddr)) {
1826                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1827                         goto martian_source;
1828         }
1829
1830         /*
1831          *      Now we are ready to route packet.
1832          */
1833         fl4.flowi4_oif = 0;
1834         fl4.flowi4_iif = dev->ifindex;
1835         fl4.flowi4_mark = skb->mark;
1836         fl4.flowi4_tos = tos;
1837         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1838         fl4.flowi4_flags = 0;
1839         fl4.daddr = daddr;
1840         fl4.saddr = saddr;
1841         err = fib_lookup(net, &fl4, &res, 0);
1842         if (err != 0) {
1843                 if (!IN_DEV_FORWARD(in_dev))
1844                         err = -EHOSTUNREACH;
1845                 goto no_route;
1846         }
1847
1848         if (res.type == RTN_BROADCAST)
1849                 goto brd_input;
1850
1851         if (res.type == RTN_LOCAL) {
1852                 err = fib_validate_source(skb, saddr, daddr, tos,
1853                                           0, dev, in_dev, &itag);
1854                 if (err < 0)
1855                         goto martian_source;
1856                 goto local_input;
1857         }
1858
1859         if (!IN_DEV_FORWARD(in_dev)) {
1860                 err = -EHOSTUNREACH;
1861                 goto no_route;
1862         }
1863         if (res.type != RTN_UNICAST)
1864                 goto martian_destination;
1865
1866         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1867 out:    return err;
1868
1869 brd_input:
1870         if (skb->protocol != htons(ETH_P_IP))
1871                 goto e_inval;
1872
1873         if (!ipv4_is_zeronet(saddr)) {
1874                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1875                                           in_dev, &itag);
1876                 if (err < 0)
1877                         goto martian_source;
1878         }
1879         flags |= RTCF_BROADCAST;
1880         res.type = RTN_BROADCAST;
1881         RT_CACHE_STAT_INC(in_brd);
1882
1883 local_input:
1884         do_cache = false;
1885         if (res.fi) {
1886                 if (!itag) {
1887                         rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1888                         if (rt_cache_valid(rth)) {
1889                                 skb_dst_set_noref(skb, &rth->dst);
1890                                 err = 0;
1891                                 goto out;
1892                         }
1893                         do_cache = true;
1894                 }
1895         }
1896
1897         rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1898                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1899         if (!rth)
1900                 goto e_nobufs;
1901
1902         rth->dst.output= ip_rt_bug;
1903 #ifdef CONFIG_IP_ROUTE_CLASSID
1904         rth->dst.tclassid = itag;
1905 #endif
1906         rth->rt_is_input = 1;
1907         if (res.table)
1908                 rth->rt_table_id = res.table->tb_id;
1909
1910         RT_CACHE_STAT_INC(in_slow_tot);
1911         if (res.type == RTN_UNREACHABLE) {
1912                 rth->dst.input= ip_error;
1913                 rth->dst.error= -err;
1914                 rth->rt_flags   &= ~RTCF_LOCAL;
1915         }
1916         if (do_cache) {
1917                 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1918                         rth->dst.flags |= DST_NOCACHE;
1919                         rt_add_uncached_list(rth);
1920                 }
1921         }
1922         skb_dst_set(skb, &rth->dst);
1923         err = 0;
1924         goto out;
1925
1926 no_route:
1927         RT_CACHE_STAT_INC(in_no_route);
1928         res.type = RTN_UNREACHABLE;
1929         res.fi = NULL;
1930         res.table = NULL;
1931         goto local_input;
1932
1933         /*
1934          *      Do not cache martian addresses: they should be logged (RFC1812)
1935          */
1936 martian_destination:
1937         RT_CACHE_STAT_INC(in_martian_dst);
1938 #ifdef CONFIG_IP_ROUTE_VERBOSE
1939         if (IN_DEV_LOG_MARTIANS(in_dev))
1940                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1941                                      &daddr, &saddr, dev->name);
1942 #endif
1943
1944 e_inval:
1945         err = -EINVAL;
1946         goto out;
1947
1948 e_nobufs:
1949         err = -ENOBUFS;
1950         goto out;
1951
1952 martian_source:
1953         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1954         goto out;
1955 }
1956
1957 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1958                          u8 tos, struct net_device *dev)
1959 {
1960         int res;
1961
1962         rcu_read_lock();
1963
1964         /* Multicast recognition logic is moved from route cache to here.
1965            The problem was that too many Ethernet cards have broken/missing
1966            hardware multicast filters :-( As result the host on multicasting
1967            network acquires a lot of useless route cache entries, sort of
1968            SDR messages from all the world. Now we try to get rid of them.
1969            Really, provided software IP multicast filter is organized
1970            reasonably (at least, hashed), it does not result in a slowdown
1971            comparing with route cache reject entries.
1972            Note, that multicast routers are not affected, because
1973            route cache entry is created eventually.
1974          */
1975         if (ipv4_is_multicast(daddr)) {
1976                 struct in_device *in_dev = __in_dev_get_rcu(dev);
1977
1978                 if (in_dev) {
1979                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1980                                                   ip_hdr(skb)->protocol);
1981                         if (our
1982 #ifdef CONFIG_IP_MROUTE
1983                                 ||
1984                             (!ipv4_is_local_multicast(daddr) &&
1985                              IN_DEV_MFORWARD(in_dev))
1986 #endif
1987                            ) {
1988                                 int res = ip_route_input_mc(skb, daddr, saddr,
1989                                                             tos, dev, our);
1990                                 rcu_read_unlock();
1991                                 return res;
1992                         }
1993                 }
1994                 rcu_read_unlock();
1995                 return -EINVAL;
1996         }
1997         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1998         rcu_read_unlock();
1999         return res;
2000 }
2001 EXPORT_SYMBOL(ip_route_input_noref);
2002
2003 /* called with rcu_read_lock() */
2004 static struct rtable *__mkroute_output(const struct fib_result *res,
2005                                        const struct flowi4 *fl4, int orig_oif,
2006                                        struct net_device *dev_out,
2007                                        unsigned int flags)
2008 {
2009         struct fib_info *fi = res->fi;
2010         struct fib_nh_exception *fnhe;
2011         struct in_device *in_dev;
2012         u16 type = res->type;
2013         struct rtable *rth;
2014         bool do_cache;
2015
2016         in_dev = __in_dev_get_rcu(dev_out);
2017         if (!in_dev)
2018                 return ERR_PTR(-EINVAL);
2019
2020         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2021                 if (ipv4_is_loopback(fl4->saddr) &&
2022                     !(dev_out->flags & IFF_LOOPBACK) &&
2023                     !netif_is_l3_master(dev_out))
2024                         return ERR_PTR(-EINVAL);
2025
2026         if (ipv4_is_lbcast(fl4->daddr))
2027                 type = RTN_BROADCAST;
2028         else if (ipv4_is_multicast(fl4->daddr))
2029                 type = RTN_MULTICAST;
2030         else if (ipv4_is_zeronet(fl4->daddr))
2031                 return ERR_PTR(-EINVAL);
2032
2033         if (dev_out->flags & IFF_LOOPBACK)
2034                 flags |= RTCF_LOCAL;
2035
2036         do_cache = true;
2037         if (type == RTN_BROADCAST) {
2038                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2039                 fi = NULL;
2040         } else if (type == RTN_MULTICAST) {
2041                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2042                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2043                                      fl4->flowi4_proto))
2044                         flags &= ~RTCF_LOCAL;
2045                 else
2046                         do_cache = false;
2047                 /* If multicast route do not exist use
2048                  * default one, but do not gateway in this case.
2049                  * Yes, it is hack.
2050                  */
2051                 if (fi && res->prefixlen < 4)
2052                         fi = NULL;
2053         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2054                    (orig_oif != dev_out->ifindex)) {
2055                 /* For local routes that require a particular output interface
2056                  * we do not want to cache the result.  Caching the result
2057                  * causes incorrect behaviour when there are multiple source
2058                  * addresses on the interface, the end result being that if the
2059                  * intended recipient is waiting on that interface for the
2060                  * packet he won't receive it because it will be delivered on
2061                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2062                  * be set to the loopback interface as well.
2063                  */
2064                 fi = NULL;
2065         }
2066
2067         fnhe = NULL;
2068         do_cache &= fi != NULL;
2069         if (do_cache) {
2070                 struct rtable __rcu **prth;
2071                 struct fib_nh *nh = &FIB_RES_NH(*res);
2072
2073                 fnhe = find_exception(nh, fl4->daddr);
2074                 if (fnhe) {
2075                         prth = &fnhe->fnhe_rth_output;
2076                         rth = rcu_dereference(*prth);
2077                         if (rth && rth->dst.expires &&
2078                             time_after(jiffies, rth->dst.expires)) {
2079                                 ip_del_fnhe(nh, fl4->daddr);
2080                                 fnhe = NULL;
2081                         } else {
2082                                 goto rt_cache;
2083                         }
2084                 }
2085
2086                 if (unlikely(fl4->flowi4_flags &
2087                              FLOWI_FLAG_KNOWN_NH &&
2088                              !(nh->nh_gw &&
2089                                nh->nh_scope == RT_SCOPE_LINK))) {
2090                         do_cache = false;
2091                         goto add;
2092                 }
2093                 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2094                 rth = rcu_dereference(*prth);
2095
2096 rt_cache:
2097                 if (rt_cache_valid(rth)) {
2098                         dst_hold(&rth->dst);
2099                         return rth;
2100                 }
2101         }
2102
2103 add:
2104         rth = rt_dst_alloc(dev_out, flags, type,
2105                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2106                            IN_DEV_CONF_GET(in_dev, NOXFRM),
2107                            do_cache);
2108         if (!rth)
2109                 return ERR_PTR(-ENOBUFS);
2110
2111         rth->rt_iif     = orig_oif ? : 0;
2112         if (res->table)
2113                 rth->rt_table_id = res->table->tb_id;
2114
2115         RT_CACHE_STAT_INC(out_slow_tot);
2116
2117         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2118                 if (flags & RTCF_LOCAL &&
2119                     !(dev_out->flags & IFF_LOOPBACK)) {
2120                         rth->dst.output = ip_mc_output;
2121                         RT_CACHE_STAT_INC(out_slow_mc);
2122                 }
2123 #ifdef CONFIG_IP_MROUTE
2124                 if (type == RTN_MULTICAST) {
2125                         if (IN_DEV_MFORWARD(in_dev) &&
2126                             !ipv4_is_local_multicast(fl4->daddr)) {
2127                                 rth->dst.input = ip_mr_input;
2128                                 rth->dst.output = ip_mc_output;
2129                         }
2130                 }
2131 #endif
2132         }
2133
2134         rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2135         if (lwtunnel_output_redirect(rth->dst.lwtstate))
2136                 rth->dst.output = lwtunnel_output;
2137
2138         return rth;
2139 }
2140
2141 /*
2142  * Major route resolver routine.
2143  */
2144
2145 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2146                                           int mp_hash)
2147 {
2148         struct net_device *dev_out = NULL;
2149         __u8 tos = RT_FL_TOS(fl4);
2150         unsigned int flags = 0;
2151         struct fib_result res;
2152         struct rtable *rth;
2153         int orig_oif;
2154         int err = -ENETUNREACH;
2155
2156         res.tclassid    = 0;
2157         res.fi          = NULL;
2158         res.table       = NULL;
2159
2160         orig_oif = fl4->flowi4_oif;
2161
2162         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2163         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2164         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2165                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2166
2167         rcu_read_lock();
2168         if (fl4->saddr) {
2169                 rth = ERR_PTR(-EINVAL);
2170                 if (ipv4_is_multicast(fl4->saddr) ||
2171                     ipv4_is_lbcast(fl4->saddr) ||
2172                     ipv4_is_zeronet(fl4->saddr))
2173                         goto out;
2174
2175                 /* I removed check for oif == dev_out->oif here.
2176                    It was wrong for two reasons:
2177                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2178                       is assigned to multiple interfaces.
2179                    2. Moreover, we are allowed to send packets with saddr
2180                       of another iface. --ANK
2181                  */
2182
2183                 if (fl4->flowi4_oif == 0 &&
2184                     (ipv4_is_multicast(fl4->daddr) ||
2185                      ipv4_is_lbcast(fl4->daddr))) {
2186                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2187                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2188                         if (!dev_out)
2189                                 goto out;
2190
2191                         /* Special hack: user can direct multicasts
2192                            and limited broadcast via necessary interface
2193                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2194                            This hack is not just for fun, it allows
2195                            vic,vat and friends to work.
2196                            They bind socket to loopback, set ttl to zero
2197                            and expect that it will work.
2198                            From the viewpoint of routing cache they are broken,
2199                            because we are not allowed to build multicast path
2200                            with loopback source addr (look, routing cache
2201                            cannot know, that ttl is zero, so that packet
2202                            will not leave this host and route is valid).
2203                            Luckily, this hack is good workaround.
2204                          */
2205
2206                         fl4->flowi4_oif = dev_out->ifindex;
2207                         goto make_route;
2208                 }
2209
2210                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2211                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2212                         if (!__ip_dev_find(net, fl4->saddr, false))
2213                                 goto out;
2214                 }
2215         }
2216
2217
2218         if (fl4->flowi4_oif) {
2219                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2220                 rth = ERR_PTR(-ENODEV);
2221                 if (!dev_out)
2222                         goto out;
2223
2224                 /* RACE: Check return value of inet_select_addr instead. */
2225                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2226                         rth = ERR_PTR(-ENETUNREACH);
2227                         goto out;
2228                 }
2229                 if (ipv4_is_local_multicast(fl4->daddr) ||
2230                     ipv4_is_lbcast(fl4->daddr) ||
2231                     fl4->flowi4_proto == IPPROTO_IGMP) {
2232                         if (!fl4->saddr)
2233                                 fl4->saddr = inet_select_addr(dev_out, 0,
2234                                                               RT_SCOPE_LINK);
2235                         goto make_route;
2236                 }
2237                 if (!fl4->saddr) {
2238                         if (ipv4_is_multicast(fl4->daddr))
2239                                 fl4->saddr = inet_select_addr(dev_out, 0,
2240                                                               fl4->flowi4_scope);
2241                         else if (!fl4->daddr)
2242                                 fl4->saddr = inet_select_addr(dev_out, 0,
2243                                                               RT_SCOPE_HOST);
2244                 }
2245         }
2246
2247         if (!fl4->daddr) {
2248                 fl4->daddr = fl4->saddr;
2249                 if (!fl4->daddr)
2250                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2251                 dev_out = net->loopback_dev;
2252                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2253                 res.type = RTN_LOCAL;
2254                 flags |= RTCF_LOCAL;
2255                 goto make_route;
2256         }
2257
2258         err = fib_lookup(net, fl4, &res, 0);
2259         if (err) {
2260                 res.fi = NULL;
2261                 res.table = NULL;
2262                 if (fl4->flowi4_oif) {
2263                         /* Apparently, routing tables are wrong. Assume,
2264                            that the destination is on link.
2265
2266                            WHY? DW.
2267                            Because we are allowed to send to iface
2268                            even if it has NO routes and NO assigned
2269                            addresses. When oif is specified, routing
2270                            tables are looked up with only one purpose:
2271                            to catch if destination is gatewayed, rather than
2272                            direct. Moreover, if MSG_DONTROUTE is set,
2273                            we send packet, ignoring both routing tables
2274                            and ifaddr state. --ANK
2275
2276
2277                            We could make it even if oif is unknown,
2278                            likely IPv6, but we do not.
2279                          */
2280
2281                         if (fl4->saddr == 0)
2282                                 fl4->saddr = inet_select_addr(dev_out, 0,
2283                                                               RT_SCOPE_LINK);
2284                         res.type = RTN_UNICAST;
2285                         goto make_route;
2286                 }
2287                 rth = ERR_PTR(err);
2288                 goto out;
2289         }
2290
2291         if (res.type == RTN_LOCAL) {
2292                 if (!fl4->saddr) {
2293                         if (res.fi->fib_prefsrc)
2294                                 fl4->saddr = res.fi->fib_prefsrc;
2295                         else
2296                                 fl4->saddr = fl4->daddr;
2297                 }
2298
2299                 /* L3 master device is the loopback for that domain */
2300                 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2301                 fl4->flowi4_oif = dev_out->ifindex;
2302                 flags |= RTCF_LOCAL;
2303                 goto make_route;
2304         }
2305
2306         fib_select_path(net, &res, fl4, mp_hash);
2307
2308         dev_out = FIB_RES_DEV(res);
2309         fl4->flowi4_oif = dev_out->ifindex;
2310
2311
2312 make_route:
2313         rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2314
2315 out:
2316         rcu_read_unlock();
2317         return rth;
2318 }
2319 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2320
2321 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2322 {
2323         return NULL;
2324 }
2325
2326 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2327 {
2328         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2329
2330         return mtu ? : dst->dev->mtu;
2331 }
2332
2333 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2334                                           struct sk_buff *skb, u32 mtu)
2335 {
2336 }
2337
2338 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2339                                        struct sk_buff *skb)
2340 {
2341 }
2342
2343 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2344                                           unsigned long old)
2345 {
2346         return NULL;
2347 }
2348
2349 static struct dst_ops ipv4_dst_blackhole_ops = {
2350         .family                 =       AF_INET,
2351         .check                  =       ipv4_blackhole_dst_check,
2352         .mtu                    =       ipv4_blackhole_mtu,
2353         .default_advmss         =       ipv4_default_advmss,
2354         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2355         .redirect               =       ipv4_rt_blackhole_redirect,
2356         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2357         .neigh_lookup           =       ipv4_neigh_lookup,
2358 };
2359
2360 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2361 {
2362         struct rtable *ort = (struct rtable *) dst_orig;
2363         struct rtable *rt;
2364
2365         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2366         if (rt) {
2367                 struct dst_entry *new = &rt->dst;
2368
2369                 new->__use = 1;
2370                 new->input = dst_discard;
2371                 new->output = dst_discard_out;
2372
2373                 new->dev = ort->dst.dev;
2374                 if (new->dev)
2375                         dev_hold(new->dev);
2376
2377                 rt->rt_is_input = ort->rt_is_input;
2378                 rt->rt_iif = ort->rt_iif;
2379                 rt->rt_pmtu = ort->rt_pmtu;
2380
2381                 rt->rt_genid = rt_genid_ipv4(net);
2382                 rt->rt_flags = ort->rt_flags;
2383                 rt->rt_type = ort->rt_type;
2384                 rt->rt_gateway = ort->rt_gateway;
2385                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2386
2387                 INIT_LIST_HEAD(&rt->rt_uncached);
2388                 dst_free(new);
2389         }
2390
2391         dst_release(dst_orig);
2392
2393         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2394 }
2395
2396 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2397                                     const struct sock *sk)
2398 {
2399         struct rtable *rt = __ip_route_output_key(net, flp4);
2400
2401         if (IS_ERR(rt))
2402                 return rt;
2403
2404         if (flp4->flowi4_proto)
2405                 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2406                                                         flowi4_to_flowi(flp4),
2407                                                         sk, 0);
2408
2409         return rt;
2410 }
2411 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2412
2413 static int rt_fill_info(struct net *net,  __be32 dst, __be32 src, u32 table_id,
2414                         struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2415                         u32 seq, int event, int nowait, unsigned int flags)
2416 {
2417         struct rtable *rt = skb_rtable(skb);
2418         struct rtmsg *r;
2419         struct nlmsghdr *nlh;
2420         unsigned long expires = 0;
2421         u32 error;
2422         u32 metrics[RTAX_MAX];
2423
2424         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2425         if (!nlh)
2426                 return -EMSGSIZE;
2427
2428         r = nlmsg_data(nlh);
2429         r->rtm_family    = AF_INET;
2430         r->rtm_dst_len  = 32;
2431         r->rtm_src_len  = 0;
2432         r->rtm_tos      = fl4->flowi4_tos;
2433         r->rtm_table    = table_id;
2434         if (nla_put_u32(skb, RTA_TABLE, table_id))
2435                 goto nla_put_failure;
2436         r->rtm_type     = rt->rt_type;
2437         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2438         r->rtm_protocol = RTPROT_UNSPEC;
2439         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2440         if (rt->rt_flags & RTCF_NOTIFY)
2441                 r->rtm_flags |= RTM_F_NOTIFY;
2442         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2443                 r->rtm_flags |= RTCF_DOREDIRECT;
2444
2445         if (nla_put_in_addr(skb, RTA_DST, dst))
2446                 goto nla_put_failure;
2447         if (src) {
2448                 r->rtm_src_len = 32;
2449                 if (nla_put_in_addr(skb, RTA_SRC, src))
2450                         goto nla_put_failure;
2451         }
2452         if (rt->dst.dev &&
2453             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2454                 goto nla_put_failure;
2455 #ifdef CONFIG_IP_ROUTE_CLASSID
2456         if (rt->dst.tclassid &&
2457             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2458                 goto nla_put_failure;
2459 #endif
2460         if (!rt_is_input_route(rt) &&
2461             fl4->saddr != src) {
2462                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2463                         goto nla_put_failure;
2464         }
2465         if (rt->rt_uses_gateway &&
2466             nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2467                 goto nla_put_failure;
2468
2469         expires = rt->dst.expires;
2470         if (expires) {
2471                 unsigned long now = jiffies;
2472
2473                 if (time_before(now, expires))
2474                         expires -= now;
2475                 else
2476                         expires = 0;
2477         }
2478
2479         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2480         if (rt->rt_pmtu && expires)
2481                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2482         if (rtnetlink_put_metrics(skb, metrics) < 0)
2483                 goto nla_put_failure;
2484
2485         if (fl4->flowi4_mark &&
2486             nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2487                 goto nla_put_failure;
2488
2489         error = rt->dst.error;
2490
2491         if (rt_is_input_route(rt)) {
2492 #ifdef CONFIG_IP_MROUTE
2493                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2494                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2495                         int err = ipmr_get_route(net, skb,
2496                                                  fl4->saddr, fl4->daddr,
2497                                                  r, nowait);
2498                         if (err <= 0) {
2499                                 if (!nowait) {
2500                                         if (err == 0)
2501                                                 return 0;
2502                                         goto nla_put_failure;
2503                                 } else {
2504                                         if (err == -EMSGSIZE)
2505                                                 goto nla_put_failure;
2506                                         error = err;
2507                                 }
2508                         }
2509                 } else
2510 #endif
2511                         if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2512                                 goto nla_put_failure;
2513         }
2514
2515         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2516                 goto nla_put_failure;
2517
2518         nlmsg_end(skb, nlh);
2519         return 0;
2520
2521 nla_put_failure:
2522         nlmsg_cancel(skb, nlh);
2523         return -EMSGSIZE;
2524 }
2525
2526 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2527 {
2528         struct net *net = sock_net(in_skb->sk);
2529         struct rtmsg *rtm;
2530         struct nlattr *tb[RTA_MAX+1];
2531         struct rtable *rt = NULL;
2532         struct flowi4 fl4;
2533         __be32 dst = 0;
2534         __be32 src = 0;
2535         u32 iif;
2536         int err;
2537         int mark;
2538         struct sk_buff *skb;
2539         u32 table_id = RT_TABLE_MAIN;
2540
2541         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2542         if (err < 0)
2543                 goto errout;
2544
2545         rtm = nlmsg_data(nlh);
2546
2547         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2548         if (!skb) {
2549                 err = -ENOBUFS;
2550                 goto errout;
2551         }
2552
2553         /* Reserve room for dummy headers, this skb can pass
2554            through good chunk of routing engine.
2555          */
2556         skb_reset_mac_header(skb);
2557         skb_reset_network_header(skb);
2558
2559         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2560         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2561         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2562
2563         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2564         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2565         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2566         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2567
2568         memset(&fl4, 0, sizeof(fl4));
2569         fl4.daddr = dst;
2570         fl4.saddr = src;
2571         fl4.flowi4_tos = rtm->rtm_tos;
2572         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2573         fl4.flowi4_mark = mark;
2574
2575         if (iif) {
2576                 struct net_device *dev;
2577
2578                 dev = __dev_get_by_index(net, iif);
2579                 if (!dev) {
2580                         err = -ENODEV;
2581                         goto errout_free;
2582                 }
2583
2584                 skb->protocol   = htons(ETH_P_IP);
2585                 skb->dev        = dev;
2586                 skb->mark       = mark;
2587                 local_bh_disable();
2588                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2589                 local_bh_enable();
2590
2591                 rt = skb_rtable(skb);
2592                 if (err == 0 && rt->dst.error)
2593                         err = -rt->dst.error;
2594         } else {
2595                 rt = ip_route_output_key(net, &fl4);
2596
2597                 err = 0;
2598                 if (IS_ERR(rt))
2599                         err = PTR_ERR(rt);
2600         }
2601
2602         if (err)
2603                 goto errout_free;
2604
2605         skb_dst_set(skb, &rt->dst);
2606         if (rtm->rtm_flags & RTM_F_NOTIFY)
2607                 rt->rt_flags |= RTCF_NOTIFY;
2608
2609         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2610                 table_id = rt->rt_table_id;
2611
2612         err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2613                            NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2614                            RTM_NEWROUTE, 0, 0);
2615         if (err < 0)
2616                 goto errout_free;
2617
2618         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2619 errout:
2620         return err;
2621
2622 errout_free:
2623         kfree_skb(skb);
2624         goto errout;
2625 }
2626
2627 void ip_rt_multicast_event(struct in_device *in_dev)
2628 {
2629         rt_cache_flush(dev_net(in_dev->dev));
2630 }
2631
2632 #ifdef CONFIG_SYSCTL
2633 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
2634 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
2635 static int ip_rt_gc_elasticity __read_mostly    = 8;
2636
2637 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2638                                         void __user *buffer,
2639                                         size_t *lenp, loff_t *ppos)
2640 {
2641         struct net *net = (struct net *)__ctl->extra1;
2642
2643         if (write) {
2644                 rt_cache_flush(net);
2645                 fnhe_genid_bump(net);
2646                 return 0;
2647         }
2648
2649         return -EINVAL;
2650 }
2651
2652 static struct ctl_table ipv4_route_table[] = {
2653         {
2654                 .procname       = "gc_thresh",
2655                 .data           = &ipv4_dst_ops.gc_thresh,
2656                 .maxlen         = sizeof(int),
2657                 .mode           = 0644,
2658                 .proc_handler   = proc_dointvec,
2659         },
2660         {
2661                 .procname       = "max_size",
2662                 .data           = &ip_rt_max_size,
2663                 .maxlen         = sizeof(int),
2664                 .mode           = 0644,
2665                 .proc_handler   = proc_dointvec,
2666         },
2667         {
2668                 /*  Deprecated. Use gc_min_interval_ms */
2669
2670                 .procname       = "gc_min_interval",
2671                 .data           = &ip_rt_gc_min_interval,
2672                 .maxlen         = sizeof(int),
2673                 .mode           = 0644,
2674                 .proc_handler   = proc_dointvec_jiffies,
2675         },
2676         {
2677                 .procname       = "gc_min_interval_ms",
2678                 .data           = &ip_rt_gc_min_interval,
2679                 .maxlen         = sizeof(int),
2680                 .mode           = 0644,
2681                 .proc_handler   = proc_dointvec_ms_jiffies,
2682         },
2683         {
2684                 .procname       = "gc_timeout",
2685                 .data           = &ip_rt_gc_timeout,
2686                 .maxlen         = sizeof(int),
2687                 .mode           = 0644,
2688                 .proc_handler   = proc_dointvec_jiffies,
2689         },
2690         {
2691                 .procname       = "gc_interval",
2692                 .data           = &ip_rt_gc_interval,
2693                 .maxlen         = sizeof(int),
2694                 .mode           = 0644,
2695                 .proc_handler   = proc_dointvec_jiffies,
2696         },
2697         {
2698                 .procname       = "redirect_load",
2699                 .data           = &ip_rt_redirect_load,
2700                 .maxlen         = sizeof(int),
2701                 .mode           = 0644,
2702                 .proc_handler   = proc_dointvec,
2703         },
2704         {
2705                 .procname       = "redirect_number",
2706                 .data           = &ip_rt_redirect_number,
2707                 .maxlen         = sizeof(int),
2708                 .mode           = 0644,
2709                 .proc_handler   = proc_dointvec,
2710         },
2711         {
2712                 .procname       = "redirect_silence",
2713                 .data           = &ip_rt_redirect_silence,
2714                 .maxlen         = sizeof(int),
2715                 .mode           = 0644,
2716                 .proc_handler   = proc_dointvec,
2717         },
2718         {
2719                 .procname       = "error_cost",
2720                 .data           = &ip_rt_error_cost,
2721                 .maxlen         = sizeof(int),
2722                 .mode           = 0644,
2723                 .proc_handler   = proc_dointvec,
2724         },
2725         {
2726                 .procname       = "error_burst",
2727                 .data           = &ip_rt_error_burst,
2728                 .maxlen         = sizeof(int),
2729                 .mode           = 0644,
2730                 .proc_handler   = proc_dointvec,
2731         },
2732         {
2733                 .procname       = "gc_elasticity",
2734                 .data           = &ip_rt_gc_elasticity,
2735                 .maxlen         = sizeof(int),
2736                 .mode           = 0644,
2737                 .proc_handler   = proc_dointvec,
2738         },
2739         {
2740                 .procname       = "mtu_expires",
2741                 .data           = &ip_rt_mtu_expires,
2742                 .maxlen         = sizeof(int),
2743                 .mode           = 0644,
2744                 .proc_handler   = proc_dointvec_jiffies,
2745         },
2746         {
2747                 .procname       = "min_pmtu",
2748                 .data           = &ip_rt_min_pmtu,
2749                 .maxlen         = sizeof(int),
2750                 .mode           = 0644,
2751                 .proc_handler   = proc_dointvec,
2752         },
2753         {
2754                 .procname       = "min_adv_mss",
2755                 .data           = &ip_rt_min_advmss,
2756                 .maxlen         = sizeof(int),
2757                 .mode           = 0644,
2758                 .proc_handler   = proc_dointvec,
2759         },
2760         { }
2761 };
2762
2763 static struct ctl_table ipv4_route_flush_table[] = {
2764         {
2765                 .procname       = "flush",
2766                 .maxlen         = sizeof(int),
2767                 .mode           = 0200,
2768                 .proc_handler   = ipv4_sysctl_rtcache_flush,
2769         },
2770         { },
2771 };
2772
2773 static __net_init int sysctl_route_net_init(struct net *net)
2774 {
2775         struct ctl_table *tbl;
2776
2777         tbl = ipv4_route_flush_table;
2778         if (!net_eq(net, &init_net)) {
2779                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2780                 if (!tbl)
2781                         goto err_dup;
2782
2783                 /* Don't export sysctls to unprivileged users */
2784                 if (net->user_ns != &init_user_ns)
2785                         tbl[0].procname = NULL;
2786         }
2787         tbl[0].extra1 = net;
2788
2789         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2790         if (!net->ipv4.route_hdr)
2791                 goto err_reg;
2792         return 0;
2793
2794 err_reg:
2795         if (tbl != ipv4_route_flush_table)
2796                 kfree(tbl);
2797 err_dup:
2798         return -ENOMEM;
2799 }
2800
2801 static __net_exit void sysctl_route_net_exit(struct net *net)
2802 {
2803         struct ctl_table *tbl;
2804
2805         tbl = net->ipv4.route_hdr->ctl_table_arg;
2806         unregister_net_sysctl_table(net->ipv4.route_hdr);
2807         BUG_ON(tbl == ipv4_route_flush_table);
2808         kfree(tbl);
2809 }
2810
2811 static __net_initdata struct pernet_operations sysctl_route_ops = {
2812         .init = sysctl_route_net_init,
2813         .exit = sysctl_route_net_exit,
2814 };
2815 #endif
2816
2817 static __net_init int rt_genid_init(struct net *net)
2818 {
2819         atomic_set(&net->ipv4.rt_genid, 0);
2820         atomic_set(&net->fnhe_genid, 0);
2821         get_random_bytes(&net->ipv4.dev_addr_genid,
2822                          sizeof(net->ipv4.dev_addr_genid));
2823         return 0;
2824 }
2825
2826 static __net_initdata struct pernet_operations rt_genid_ops = {
2827         .init = rt_genid_init,
2828 };
2829
2830 static int __net_init ipv4_inetpeer_init(struct net *net)
2831 {
2832         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2833
2834         if (!bp)
2835                 return -ENOMEM;
2836         inet_peer_base_init(bp);
2837         net->ipv4.peers = bp;
2838         return 0;
2839 }
2840
2841 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2842 {
2843         struct inet_peer_base *bp = net->ipv4.peers;
2844
2845         net->ipv4.peers = NULL;
2846         inetpeer_invalidate_tree(bp);
2847         kfree(bp);
2848 }
2849
2850 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2851         .init   =       ipv4_inetpeer_init,
2852         .exit   =       ipv4_inetpeer_exit,
2853 };
2854
2855 #ifdef CONFIG_IP_ROUTE_CLASSID
2856 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2857 #endif /* CONFIG_IP_ROUTE_CLASSID */
2858
2859 int __init ip_rt_init(void)
2860 {
2861         int rc = 0;
2862         int cpu;
2863
2864         ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2865         if (!ip_idents)
2866                 panic("IP: failed to allocate ip_idents\n");
2867
2868         prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2869
2870         ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2871         if (!ip_tstamps)
2872                 panic("IP: failed to allocate ip_tstamps\n");
2873
2874         for_each_possible_cpu(cpu) {
2875                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2876
2877                 INIT_LIST_HEAD(&ul->head);
2878                 spin_lock_init(&ul->lock);
2879         }
2880 #ifdef CONFIG_IP_ROUTE_CLASSID
2881         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2882         if (!ip_rt_acct)
2883                 panic("IP: failed to allocate ip_rt_acct\n");
2884 #endif
2885
2886         ipv4_dst_ops.kmem_cachep =
2887                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2888                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2889
2890         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2891
2892         if (dst_entries_init(&ipv4_dst_ops) < 0)
2893                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2894
2895         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2896                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2897
2898         ipv4_dst_ops.gc_thresh = ~0;
2899         ip_rt_max_size = INT_MAX;
2900
2901         devinet_init();
2902         ip_fib_init();
2903
2904         if (ip_rt_proc_init())
2905                 pr_err("Unable to create route proc files\n");
2906 #ifdef CONFIG_XFRM
2907         xfrm_init();
2908         xfrm4_init();
2909 #endif
2910         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2911
2912 #ifdef CONFIG_SYSCTL
2913         register_pernet_subsys(&sysctl_route_ops);
2914 #endif
2915         register_pernet_subsys(&rt_genid_ops);
2916         register_pernet_subsys(&ipv4_inetpeer_ops);
2917         return rc;
2918 }
2919
2920 #ifdef CONFIG_SYSCTL
2921 /*
2922  * We really need to sanitize the damn ipv4 init order, then all
2923  * this nonsense will go away.
2924  */
2925 void __init ip_static_sysctl_init(void)
2926 {
2927         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2928 }
2929 #endif