net/ipv4/route.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              ROUTE - implementation of the IP router.
   7  *
   8  * Authors:     Ross Biro
   9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  11  *              Linus Torvalds, <Linus.Torvalds@helsinki.fi>
  12  *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  13  *
  14  * Fixes:
  15  *              Alan Cox        :       Verify area fixes.
  16  *              Alan Cox        :       cli() protects routing changes
  17  *              Rui Oliveira    :       ICMP routing table updates
  18  *              (rco@di.uminho.pt)      Routing table insertion and update
  19  *              Linus Torvalds  :       Rewrote bits to be sensible
  20  *              Alan Cox        :       Added BSD route gw semantics
  21  *              Alan Cox        :       Super /proc >4K
  22  *              Alan Cox        :       MTU in route table
  23  *              Alan Cox        :       MSS actually. Also added the window
  24  *                                      clamper.
  25  *              Sam Lantinga    :       Fixed route matching in rt_del()
  26  *              Alan Cox        :       Routing cache support.
  27  *              Alan Cox        :       Removed compatibility cruft.
  28  *              Alan Cox        :       RTF_REJECT support.
  29  *              Alan Cox        :       TCP irtt support.
  30  *              Jonathan Naylor :       Added Metric support.
  31  *      Miquel van Smoorenburg  :       BSD API fixes.
  32  *      Miquel van Smoorenburg  :       Metrics.
  33  *              Alan Cox        :       Use __u32 properly
  34  *              Alan Cox        :       Aligned routing errors more closely with BSD
  35  *                                      our system is still very different.
  36  *              Alan Cox        :       Faster /proc handling
  37  *      Alexey Kuznetsov        :       Massive rework to support tree based routing,
  38  *                                      routing caches and better behaviour.
  39  *
  40  *              Olaf Erb        :       irtt wasn't being copied right.
  41  *              Bjorn Ekwall    :       Kerneld route support.
  42  *              Alan Cox        :       Multicast fixed (I hope)
  43  *              Pavel Krauz     :       Limited broadcast fixed
  44  *              Mike McLagan    :       Routing by source
  45  *      Alexey Kuznetsov        :       End of old history. Split to fib.c and
  46  *                                      route.c and rewritten from scratch.
  47  *              Andi Kleen      :       Load-limit warning messages.
  48  *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
  49  *      Vitaly E. Lavrov        :       Race condition in ip_route_input_slow.
  50  *      Tobias Ringstrom        :       Uninitialized res.type in ip_route_output_slow.
  51  *      Vladimir V. Ivanov      :       IP rule info (flowid) is really useful.
  52  *              Marc Boucher    :       routing by fwmark
  53  *      Robert Olsson           :       Added rt_cache statistics
  54  *      Arnaldo C. Melo         :       Convert proc stuff to seq_file
  55  *      Eric Dumazet            :       hashed spinlocks and rt_check_expire() fixes.
  56  *      Ilia Sotnikov           :       Ignore TOS on PMTUD and Redirect
  57  *      Ilia Sotnikov           :       Removed TOS from hash calculations
  58  *
  59  *              This program is free software; you can redistribute it and/or
  60  *              modify it under the terms of the GNU General Public License
  61  *              as published by the Free Software Foundation; either version
  62  *              2 of the License, or (at your option) any later version.
  63  */
  64
  65 #define pr_fmt(fmt) "IPv4: " fmt
  66
  67 #include <linux/module.h>
  68 #include <asm/uaccess.h>
  69 #include <linux/bitops.h>
  70 #include <linux/types.h>
  71 #include <linux/kernel.h>
  72 #include <linux/mm.h>
  73 #include <linux/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_BH(net, IPSTATS_MIB_INADDRERRORS);
 919                         break;
 920
 921                 case ENETUNREACH:
 922                         IP_INC_STATS_BH(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_BH(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         return min_t(unsigned int, mtu, IP_MAX_MTU);
1250 }
1251
1252 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1253 {
1254         struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1255         struct fib_nh_exception *fnhe;
1256         u32 hval;
1257
1258         if (!hash)
1259                 return NULL;
1260
1261         hval = fnhe_hashfun(daddr);
1262
1263         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1264              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1265                 if (fnhe->fnhe_daddr == daddr)
1266                         return fnhe;
1267         }
1268         return NULL;
1269 }
1270
1271 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1272                               __be32 daddr)
1273 {
1274         bool ret = false;
1275
1276         spin_lock_bh(&fnhe_lock);
1277
1278         if (daddr == fnhe->fnhe_daddr) {
1279                 struct rtable __rcu **porig;
1280                 struct rtable *orig;
1281                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1282
1283                 if (rt_is_input_route(rt))
1284                         porig = &fnhe->fnhe_rth_input;
1285                 else
1286                         porig = &fnhe->fnhe_rth_output;
1287                 orig = rcu_dereference(*porig);
1288
1289                 if (fnhe->fnhe_genid != genid) {
1290                         fnhe->fnhe_genid = genid;
1291                         fnhe->fnhe_gw = 0;
1292                         fnhe->fnhe_pmtu = 0;
1293                         fnhe->fnhe_expires = 0;
1294                         fnhe_flush_routes(fnhe);
1295                         orig = NULL;
1296                 }
1297                 fill_route_from_fnhe(rt, fnhe);
1298                 if (!rt->rt_gateway)
1299                         rt->rt_gateway = daddr;
1300
1301                 if (!(rt->dst.flags & DST_NOCACHE)) {
1302                         rcu_assign_pointer(*porig, rt);
1303                         if (orig)
1304                                 rt_free(orig);
1305                         ret = true;
1306                 }
1307
1308                 fnhe->fnhe_stamp = jiffies;
1309         }
1310         spin_unlock_bh(&fnhe_lock);
1311
1312         return ret;
1313 }
1314
1315 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1316 {
1317         struct rtable *orig, *prev, **p;
1318         bool ret = true;
1319
1320         if (rt_is_input_route(rt)) {
1321                 p = (struct rtable **)&nh->nh_rth_input;
1322         } else {
1323                 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1324         }
1325         orig = *p;
1326
1327         prev = cmpxchg(p, orig, rt);
1328         if (prev == orig) {
1329                 if (orig)
1330                         rt_free(orig);
1331         } else
1332                 ret = false;
1333
1334         return ret;
1335 }
1336
1337 struct uncached_list {
1338         spinlock_t              lock;
1339         struct list_head        head;
1340 };
1341
1342 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1343
1344 static void rt_add_uncached_list(struct rtable *rt)
1345 {
1346         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1347
1348         rt->rt_uncached_list = ul;
1349
1350         spin_lock_bh(&ul->lock);
1351         list_add_tail(&rt->rt_uncached, &ul->head);
1352         spin_unlock_bh(&ul->lock);
1353 }
1354
1355 static void ipv4_dst_destroy(struct dst_entry *dst)
1356 {
1357         struct rtable *rt = (struct rtable *) dst;
1358
1359         if (!list_empty(&rt->rt_uncached)) {
1360                 struct uncached_list *ul = rt->rt_uncached_list;
1361
1362                 spin_lock_bh(&ul->lock);
1363                 list_del(&rt->rt_uncached);
1364                 spin_unlock_bh(&ul->lock);
1365         }
1366 }
1367
1368 void rt_flush_dev(struct net_device *dev)
1369 {
1370         struct net *net = dev_net(dev);
1371         struct rtable *rt;
1372         int cpu;
1373
1374         for_each_possible_cpu(cpu) {
1375                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1376
1377                 spin_lock_bh(&ul->lock);
1378                 list_for_each_entry(rt, &ul->head, rt_uncached) {
1379                         if (rt->dst.dev != dev)
1380                                 continue;
1381                         rt->dst.dev = net->loopback_dev;
1382                         dev_hold(rt->dst.dev);
1383                         dev_put(dev);
1384                 }
1385                 spin_unlock_bh(&ul->lock);
1386         }
1387 }
1388
1389 static bool rt_cache_valid(const struct rtable *rt)
1390 {
1391         return  rt &&
1392                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1393                 !rt_is_expired(rt);
1394 }
1395
1396 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1397                            const struct fib_result *res,
1398                            struct fib_nh_exception *fnhe,
1399                            struct fib_info *fi, u16 type, u32 itag)
1400 {
1401         bool cached = false;
1402
1403         if (fi) {
1404                 struct fib_nh *nh = &FIB_RES_NH(*res);
1405
1406                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1407                         rt->rt_gateway = nh->nh_gw;
1408                         rt->rt_uses_gateway = 1;
1409                 }
1410                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1411 #ifdef CONFIG_IP_ROUTE_CLASSID
1412                 rt->dst.tclassid = nh->nh_tclassid;
1413 #endif
1414                 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1415                 if (unlikely(fnhe))
1416                         cached = rt_bind_exception(rt, fnhe, daddr);
1417                 else if (!(rt->dst.flags & DST_NOCACHE))
1418                         cached = rt_cache_route(nh, rt);
1419                 if (unlikely(!cached)) {
1420                         /* Routes we intend to cache in nexthop exception or
1421                          * FIB nexthop have the DST_NOCACHE bit clear.
1422                          * However, if we are unsuccessful at storing this
1423                          * route into the cache we really need to set it.
1424                          */
1425                         rt->dst.flags |= DST_NOCACHE;
1426                         if (!rt->rt_gateway)
1427                                 rt->rt_gateway = daddr;
1428                         rt_add_uncached_list(rt);
1429                 }
1430         } else
1431                 rt_add_uncached_list(rt);
1432
1433 #ifdef CONFIG_IP_ROUTE_CLASSID
1434 #ifdef CONFIG_IP_MULTIPLE_TABLES
1435         set_class_tag(rt, res->tclassid);
1436 #endif
1437         set_class_tag(rt, itag);
1438 #endif
1439 }
1440
1441 static struct rtable *rt_dst_alloc(struct net_device *dev,
1442                                    unsigned int flags, u16 type,
1443                                    bool nopolicy, bool noxfrm, bool will_cache)
1444 {
1445         struct rtable *rt;
1446
1447         rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1448                        (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1449                        (nopolicy ? DST_NOPOLICY : 0) |
1450                        (noxfrm ? DST_NOXFRM : 0));
1451
1452         if (rt) {
1453                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1454                 rt->rt_flags = flags;
1455                 rt->rt_type = type;
1456                 rt->rt_is_input = 0;
1457                 rt->rt_iif = 0;
1458                 rt->rt_pmtu = 0;
1459                 rt->rt_gateway = 0;
1460                 rt->rt_uses_gateway = 0;
1461                 rt->rt_table_id = 0;
1462                 INIT_LIST_HEAD(&rt->rt_uncached);
1463
1464                 rt->dst.output = ip_output;
1465                 if (flags & RTCF_LOCAL)
1466                         rt->dst.input = ip_local_deliver;
1467         }
1468
1469         return rt;
1470 }
1471
1472 /* called in rcu_read_lock() section */
1473 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1474                                 u8 tos, struct net_device *dev, int our)
1475 {
1476         struct rtable *rth;
1477         struct in_device *in_dev = __in_dev_get_rcu(dev);
1478         unsigned int flags = RTCF_MULTICAST;
1479         u32 itag = 0;
1480         int err;
1481
1482         /* Primary sanity checks. */
1483
1484         if (!in_dev)
1485                 return -EINVAL;
1486
1487         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1488             skb->protocol != htons(ETH_P_IP))
1489                 goto e_inval;
1490
1491         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1492                 goto e_inval;
1493
1494         if (ipv4_is_zeronet(saddr)) {
1495                 if (!ipv4_is_local_multicast(daddr))
1496                         goto e_inval;
1497         } else {
1498                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1499                                           in_dev, &itag);
1500                 if (err < 0)
1501                         goto e_err;
1502         }
1503         if (our)
1504                 flags |= RTCF_LOCAL;
1505
1506         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1507                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1508         if (!rth)
1509                 goto e_nobufs;
1510
1511 #ifdef CONFIG_IP_ROUTE_CLASSID
1512         rth->dst.tclassid = itag;
1513 #endif
1514         rth->dst.output = ip_rt_bug;
1515         rth->rt_is_input= 1;
1516
1517 #ifdef CONFIG_IP_MROUTE
1518         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1519                 rth->dst.input = ip_mr_input;
1520 #endif
1521         RT_CACHE_STAT_INC(in_slow_mc);
1522
1523         skb_dst_set(skb, &rth->dst);
1524         return 0;
1525
1526 e_nobufs:
1527         return -ENOBUFS;
1528 e_inval:
1529         return -EINVAL;
1530 e_err:
1531         return err;
1532 }
1533
1534
1535 static void ip_handle_martian_source(struct net_device *dev,
1536                                      struct in_device *in_dev,
1537                                      struct sk_buff *skb,
1538                                      __be32 daddr,
1539                                      __be32 saddr)
1540 {
1541         RT_CACHE_STAT_INC(in_martian_src);
1542 #ifdef CONFIG_IP_ROUTE_VERBOSE
1543         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1544                 /*
1545                  *      RFC1812 recommendation, if source is martian,
1546                  *      the only hint is MAC header.
1547                  */
1548                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1549                         &daddr, &saddr, dev->name);
1550                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1551                         print_hex_dump(KERN_WARNING, "ll header: ",
1552                                        DUMP_PREFIX_OFFSET, 16, 1,
1553                                        skb_mac_header(skb),
1554                                        dev->hard_header_len, true);
1555                 }
1556         }
1557 #endif
1558 }
1559
1560 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1561 {
1562         struct fnhe_hash_bucket *hash;
1563         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1564         u32 hval = fnhe_hashfun(daddr);
1565
1566         spin_lock_bh(&fnhe_lock);
1567
1568         hash = rcu_dereference_protected(nh->nh_exceptions,
1569                                          lockdep_is_held(&fnhe_lock));
1570         hash += hval;
1571
1572         fnhe_p = &hash->chain;
1573         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1574         while (fnhe) {
1575                 if (fnhe->fnhe_daddr == daddr) {
1576                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1577                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1578                         fnhe_flush_routes(fnhe);
1579                         kfree_rcu(fnhe, rcu);
1580                         break;
1581                 }
1582                 fnhe_p = &fnhe->fnhe_next;
1583                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1584                                                  lockdep_is_held(&fnhe_lock));
1585         }
1586
1587         spin_unlock_bh(&fnhe_lock);
1588 }
1589
1590 /* called in rcu_read_lock() section */
1591 static int __mkroute_input(struct sk_buff *skb,
1592                            const struct fib_result *res,
1593                            struct in_device *in_dev,
1594                            __be32 daddr, __be32 saddr, u32 tos)
1595 {
1596         struct fib_nh_exception *fnhe;
1597         struct rtable *rth;
1598         int err;
1599         struct in_device *out_dev;
1600         bool do_cache;
1601         u32 itag = 0;
1602
1603         /* get a working reference to the output device */
1604         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1605         if (!out_dev) {
1606                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1607                 return -EINVAL;
1608         }
1609
1610         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1611                                   in_dev->dev, in_dev, &itag);
1612         if (err < 0) {
1613                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1614                                          saddr);
1615
1616                 goto cleanup;
1617         }
1618
1619         do_cache = res->fi && !itag;
1620         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1621             skb->protocol == htons(ETH_P_IP) &&
1622             (IN_DEV_SHARED_MEDIA(out_dev) ||
1623              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1624                 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1625
1626         if (skb->protocol != htons(ETH_P_IP)) {
1627                 /* Not IP (i.e. ARP). Do not create route, if it is
1628                  * invalid for proxy arp. DNAT routes are always valid.
1629                  *
1630                  * Proxy arp feature have been extended to allow, ARP
1631                  * replies back to the same interface, to support
1632                  * Private VLAN switch technologies. See arp.c.
1633                  */
1634                 if (out_dev == in_dev &&
1635                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1636                         err = -EINVAL;
1637                         goto cleanup;
1638                 }
1639         }
1640
1641         fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1642         if (do_cache) {
1643                 if (fnhe) {
1644                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1645                         if (rth && rth->dst.expires &&
1646                             time_after(jiffies, rth->dst.expires)) {
1647                                 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1648                                 fnhe = NULL;
1649                         } else {
1650                                 goto rt_cache;
1651                         }
1652                 }
1653
1654                 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1655
1656 rt_cache:
1657                 if (rt_cache_valid(rth)) {
1658                         skb_dst_set_noref(skb, &rth->dst);
1659                         goto out;
1660                 }
1661         }
1662
1663         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1664                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1665                            IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1666         if (!rth) {
1667                 err = -ENOBUFS;
1668                 goto cleanup;
1669         }
1670
1671         rth->rt_is_input = 1;
1672         if (res->table)
1673                 rth->rt_table_id = res->table->tb_id;
1674         RT_CACHE_STAT_INC(in_slow_tot);
1675
1676         rth->dst.input = ip_forward;
1677
1678         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1679         if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1680                 rth->dst.lwtstate->orig_output = rth->dst.output;
1681                 rth->dst.output = lwtunnel_output;
1682         }
1683         if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1684                 rth->dst.lwtstate->orig_input = rth->dst.input;
1685                 rth->dst.input = lwtunnel_input;
1686         }
1687         skb_dst_set(skb, &rth->dst);
1688 out:
1689         err = 0;
1690  cleanup:
1691         return err;
1692 }
1693
1694 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1695
1696 /* To make ICMP packets follow the right flow, the multipath hash is
1697  * calculated from the inner IP addresses in reverse order.
1698  */
1699 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1700 {
1701         const struct iphdr *outer_iph = ip_hdr(skb);
1702         struct icmphdr _icmph;
1703         const struct icmphdr *icmph;
1704         struct iphdr _inner_iph;
1705         const struct iphdr *inner_iph;
1706
1707         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1708                 goto standard_hash;
1709
1710         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1711                                    &_icmph);
1712         if (!icmph)
1713                 goto standard_hash;
1714
1715         if (icmph->type != ICMP_DEST_UNREACH &&
1716             icmph->type != ICMP_REDIRECT &&
1717             icmph->type != ICMP_TIME_EXCEEDED &&
1718             icmph->type != ICMP_PARAMETERPROB) {
1719                 goto standard_hash;
1720         }
1721
1722         inner_iph = skb_header_pointer(skb,
1723                                        outer_iph->ihl * 4 + sizeof(_icmph),
1724                                        sizeof(_inner_iph), &_inner_iph);
1725         if (!inner_iph)
1726                 goto standard_hash;
1727
1728         return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1729
1730 standard_hash:
1731         return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1732 }
1733
1734 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1735
1736 static int ip_mkroute_input(struct sk_buff *skb,
1737                             struct fib_result *res,
1738                             const struct flowi4 *fl4,
1739                             struct in_device *in_dev,
1740                             __be32 daddr, __be32 saddr, u32 tos)
1741 {
1742 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1743         if (res->fi && res->fi->fib_nhs > 1) {
1744                 int h;
1745
1746                 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1747                         h = ip_multipath_icmp_hash(skb);
1748                 else
1749                         h = fib_multipath_hash(saddr, daddr);
1750                 fib_select_multipath(res, h);
1751         }
1752 #endif
1753
1754         /* create a routing cache entry */
1755         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1756 }
1757
1758 /*
1759  *      NOTE. We drop all the packets that has local source
1760  *      addresses, because every properly looped back packet
1761  *      must have correct destination already attached by output routine.
1762  *
1763  *      Such approach solves two big problems:
1764  *      1. Not simplex devices are handled properly.
1765  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1766  *      called with rcu_read_lock()
1767  */
1768
1769 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1770                                u8 tos, struct net_device *dev)
1771 {
1772         struct fib_result res;
1773         struct in_device *in_dev = __in_dev_get_rcu(dev);
1774         struct ip_tunnel_info *tun_info;
1775         struct flowi4   fl4;
1776         unsigned int    flags = 0;
1777         u32             itag = 0;
1778         struct rtable   *rth;
1779         int             err = -EINVAL;
1780         struct net    *net = dev_net(dev);
1781         bool do_cache;
1782
1783         /* IP on this device is disabled. */
1784
1785         if (!in_dev)
1786                 goto out;
1787
1788         /* Check for the most weird martians, which can be not detected
1789            by fib_lookup.
1790          */
1791
1792         tun_info = skb_tunnel_info(skb);
1793         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1794                 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1795         else
1796                 fl4.flowi4_tun_key.tun_id = 0;
1797         skb_dst_drop(skb);
1798
1799         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1800                 goto martian_source;
1801
1802         res.fi = NULL;
1803         res.table = NULL;
1804         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1805                 goto brd_input;
1806
1807         /* Accept zero addresses only to limited broadcast;
1808          * I even do not know to fix it or not. Waiting for complains :-)
1809          */
1810         if (ipv4_is_zeronet(saddr))
1811                 goto martian_source;
1812
1813         if (ipv4_is_zeronet(daddr))
1814                 goto martian_destination;
1815
1816         /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1817          * and call it once if daddr or/and saddr are loopback addresses
1818          */
1819         if (ipv4_is_loopback(daddr)) {
1820                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1821                         goto martian_destination;
1822         } else if (ipv4_is_loopback(saddr)) {
1823                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1824                         goto martian_source;
1825         }
1826
1827         /*
1828          *      Now we are ready to route packet.
1829          */
1830         fl4.flowi4_oif = 0;
1831         fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev);
1832         fl4.flowi4_mark = skb->mark;
1833         fl4.flowi4_tos = tos;
1834         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1835         fl4.flowi4_flags = 0;
1836         fl4.daddr = daddr;
1837         fl4.saddr = saddr;
1838         err = fib_lookup(net, &fl4, &res, 0);
1839         if (err != 0) {
1840                 if (!IN_DEV_FORWARD(in_dev))
1841                         err = -EHOSTUNREACH;
1842                 goto no_route;
1843         }
1844
1845         if (res.type == RTN_BROADCAST)
1846                 goto brd_input;
1847
1848         if (res.type == RTN_LOCAL) {
1849                 err = fib_validate_source(skb, saddr, daddr, tos,
1850                                           0, dev, in_dev, &itag);
1851                 if (err < 0)
1852                         goto martian_source;
1853                 goto local_input;
1854         }
1855
1856         if (!IN_DEV_FORWARD(in_dev)) {
1857                 err = -EHOSTUNREACH;
1858                 goto no_route;
1859         }
1860         if (res.type != RTN_UNICAST)
1861                 goto martian_destination;
1862
1863         err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1864 out:    return err;
1865
1866 brd_input:
1867         if (skb->protocol != htons(ETH_P_IP))
1868                 goto e_inval;
1869
1870         if (!ipv4_is_zeronet(saddr)) {
1871                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1872                                           in_dev, &itag);
1873                 if (err < 0)
1874                         goto martian_source;
1875         }
1876         flags |= RTCF_BROADCAST;
1877         res.type = RTN_BROADCAST;
1878         RT_CACHE_STAT_INC(in_brd);
1879
1880 local_input:
1881         do_cache = false;
1882         if (res.fi) {
1883                 if (!itag) {
1884                         rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1885                         if (rt_cache_valid(rth)) {
1886                                 skb_dst_set_noref(skb, &rth->dst);
1887                                 err = 0;
1888                                 goto out;
1889                         }
1890                         do_cache = true;
1891                 }
1892         }
1893
1894         rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1895                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1896         if (!rth)
1897                 goto e_nobufs;
1898
1899         rth->dst.output= ip_rt_bug;
1900 #ifdef CONFIG_IP_ROUTE_CLASSID
1901         rth->dst.tclassid = itag;
1902 #endif
1903         rth->rt_is_input = 1;
1904         if (res.table)
1905                 rth->rt_table_id = res.table->tb_id;
1906
1907         RT_CACHE_STAT_INC(in_slow_tot);
1908         if (res.type == RTN_UNREACHABLE) {
1909                 rth->dst.input= ip_error;
1910                 rth->dst.error= -err;
1911                 rth->rt_flags   &= ~RTCF_LOCAL;
1912         }
1913         if (do_cache) {
1914                 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1915                         rth->dst.flags |= DST_NOCACHE;
1916                         rt_add_uncached_list(rth);
1917                 }
1918         }
1919         skb_dst_set(skb, &rth->dst);
1920         err = 0;
1921         goto out;
1922
1923 no_route:
1924         RT_CACHE_STAT_INC(in_no_route);
1925         res.type = RTN_UNREACHABLE;
1926         res.fi = NULL;
1927         res.table = NULL;
1928         goto local_input;
1929
1930         /*
1931          *      Do not cache martian addresses: they should be logged (RFC1812)
1932          */
1933 martian_destination:
1934         RT_CACHE_STAT_INC(in_martian_dst);
1935 #ifdef CONFIG_IP_ROUTE_VERBOSE
1936         if (IN_DEV_LOG_MARTIANS(in_dev))
1937                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1938                                      &daddr, &saddr, dev->name);
1939 #endif
1940
1941 e_inval:
1942         err = -EINVAL;
1943         goto out;
1944
1945 e_nobufs:
1946         err = -ENOBUFS;
1947         goto out;
1948
1949 martian_source:
1950         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1951         goto out;
1952 }
1953
1954 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1955                          u8 tos, struct net_device *dev)
1956 {
1957         int res;
1958
1959         rcu_read_lock();
1960
1961         /* Multicast recognition logic is moved from route cache to here.
1962            The problem was that too many Ethernet cards have broken/missing
1963            hardware multicast filters :-( As result the host on multicasting
1964            network acquires a lot of useless route cache entries, sort of
1965            SDR messages from all the world. Now we try to get rid of them.
1966            Really, provided software IP multicast filter is organized
1967            reasonably (at least, hashed), it does not result in a slowdown
1968            comparing with route cache reject entries.
1969            Note, that multicast routers are not affected, because
1970            route cache entry is created eventually.
1971          */
1972         if (ipv4_is_multicast(daddr)) {
1973                 struct in_device *in_dev = __in_dev_get_rcu(dev);
1974
1975                 if (in_dev) {
1976                         int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1977                                                   ip_hdr(skb)->protocol);
1978                         if (our
1979 #ifdef CONFIG_IP_MROUTE
1980                                 ||
1981                             (!ipv4_is_local_multicast(daddr) &&
1982                              IN_DEV_MFORWARD(in_dev))
1983 #endif
1984                            ) {
1985                                 int res = ip_route_input_mc(skb, daddr, saddr,
1986                                                             tos, dev, our);
1987                                 rcu_read_unlock();
1988                                 return res;
1989                         }
1990                 }
1991                 rcu_read_unlock();
1992                 return -EINVAL;
1993         }
1994         res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1995         rcu_read_unlock();
1996         return res;
1997 }
1998 EXPORT_SYMBOL(ip_route_input_noref);
1999
2000 /* called with rcu_read_lock() */
2001 static struct rtable *__mkroute_output(const struct fib_result *res,
2002                                        const struct flowi4 *fl4, int orig_oif,
2003                                        struct net_device *dev_out,
2004                                        unsigned int flags)
2005 {
2006         struct fib_info *fi = res->fi;
2007         struct fib_nh_exception *fnhe;
2008         struct in_device *in_dev;
2009         u16 type = res->type;
2010         struct rtable *rth;
2011         bool do_cache;
2012
2013         in_dev = __in_dev_get_rcu(dev_out);
2014         if (!in_dev)
2015                 return ERR_PTR(-EINVAL);
2016
2017         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2018                 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2019                         return ERR_PTR(-EINVAL);
2020
2021         if (ipv4_is_lbcast(fl4->daddr))
2022                 type = RTN_BROADCAST;
2023         else if (ipv4_is_multicast(fl4->daddr))
2024                 type = RTN_MULTICAST;
2025         else if (ipv4_is_zeronet(fl4->daddr))
2026                 return ERR_PTR(-EINVAL);
2027
2028         if (dev_out->flags & IFF_LOOPBACK)
2029                 flags |= RTCF_LOCAL;
2030
2031         do_cache = true;
2032         if (type == RTN_BROADCAST) {
2033                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2034                 fi = NULL;
2035         } else if (type == RTN_MULTICAST) {
2036                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2037                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2038                                      fl4->flowi4_proto))
2039                         flags &= ~RTCF_LOCAL;
2040                 else
2041                         do_cache = false;
2042                 /* If multicast route do not exist use
2043                  * default one, but do not gateway in this case.
2044                  * Yes, it is hack.
2045                  */
2046                 if (fi && res->prefixlen < 4)
2047                         fi = NULL;
2048         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2049                    (orig_oif != dev_out->ifindex)) {
2050                 /* For local routes that require a particular output interface
2051                  * we do not want to cache the result.  Caching the result
2052                  * causes incorrect behaviour when there are multiple source
2053                  * addresses on the interface, the end result being that if the
2054                  * intended recipient is waiting on that interface for the
2055                  * packet he won't receive it because it will be delivered on
2056                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2057                  * be set to the loopback interface as well.
2058                  */
2059                 fi = NULL;
2060         }
2061
2062         fnhe = NULL;
2063         do_cache &= fi != NULL;
2064         if (do_cache) {
2065                 struct rtable __rcu **prth;
2066                 struct fib_nh *nh = &FIB_RES_NH(*res);
2067
2068                 fnhe = find_exception(nh, fl4->daddr);
2069                 if (fnhe) {
2070                         prth = &fnhe->fnhe_rth_output;
2071                         rth = rcu_dereference(*prth);
2072                         if (rth && rth->dst.expires &&
2073                             time_after(jiffies, rth->dst.expires)) {
2074                                 ip_del_fnhe(nh, fl4->daddr);
2075                                 fnhe = NULL;
2076                         } else {
2077                                 goto rt_cache;
2078                         }
2079                 }
2080
2081                 if (unlikely(fl4->flowi4_flags &
2082                              FLOWI_FLAG_KNOWN_NH &&
2083                              !(nh->nh_gw &&
2084                                nh->nh_scope == RT_SCOPE_LINK))) {
2085                         do_cache = false;
2086                         goto add;
2087                 }
2088                 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2089                 rth = rcu_dereference(*prth);
2090
2091 rt_cache:
2092                 if (rt_cache_valid(rth)) {
2093                         dst_hold(&rth->dst);
2094                         return rth;
2095                 }
2096         }
2097
2098 add:
2099         rth = rt_dst_alloc(dev_out, flags, type,
2100                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2101                            IN_DEV_CONF_GET(in_dev, NOXFRM),
2102                            do_cache);
2103         if (!rth)
2104                 return ERR_PTR(-ENOBUFS);
2105
2106         rth->rt_iif     = orig_oif ? : 0;
2107         if (res->table)
2108                 rth->rt_table_id = res->table->tb_id;
2109
2110         RT_CACHE_STAT_INC(out_slow_tot);
2111
2112         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2113                 if (flags & RTCF_LOCAL &&
2114                     !(dev_out->flags & IFF_LOOPBACK)) {
2115                         rth->dst.output = ip_mc_output;
2116                         RT_CACHE_STAT_INC(out_slow_mc);
2117                 }
2118 #ifdef CONFIG_IP_MROUTE
2119                 if (type == RTN_MULTICAST) {
2120                         if (IN_DEV_MFORWARD(in_dev) &&
2121                             !ipv4_is_local_multicast(fl4->daddr)) {
2122                                 rth->dst.input = ip_mr_input;
2123                                 rth->dst.output = ip_mc_output;
2124                         }
2125                 }
2126 #endif
2127         }
2128
2129         rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2130         if (lwtunnel_output_redirect(rth->dst.lwtstate))
2131                 rth->dst.output = lwtunnel_output;
2132
2133         return rth;
2134 }
2135
2136 /*
2137  * Major route resolver routine.
2138  */
2139
2140 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2141                                           int mp_hash)
2142 {
2143         struct net_device *dev_out = NULL;
2144         __u8 tos = RT_FL_TOS(fl4);
2145         unsigned int flags = 0;
2146         struct fib_result res;
2147         struct rtable *rth;
2148         int orig_oif;
2149         int err = -ENETUNREACH;
2150
2151         res.tclassid    = 0;
2152         res.fi          = NULL;
2153         res.table       = NULL;
2154
2155         orig_oif = fl4->flowi4_oif;
2156
2157         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2158         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2159         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2160                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2161
2162         rcu_read_lock();
2163         if (fl4->saddr) {
2164                 rth = ERR_PTR(-EINVAL);
2165                 if (ipv4_is_multicast(fl4->saddr) ||
2166                     ipv4_is_lbcast(fl4->saddr) ||
2167                     ipv4_is_zeronet(fl4->saddr))
2168                         goto out;
2169
2170                 /* I removed check for oif == dev_out->oif here.
2171                    It was wrong for two reasons:
2172                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2173                       is assigned to multiple interfaces.
2174                    2. Moreover, we are allowed to send packets with saddr
2175                       of another iface. --ANK
2176                  */
2177
2178                 if (fl4->flowi4_oif == 0 &&
2179                     (ipv4_is_multicast(fl4->daddr) ||
2180                      ipv4_is_lbcast(fl4->daddr))) {
2181                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2182                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2183                         if (!dev_out)
2184                                 goto out;
2185
2186                         /* Special hack: user can direct multicasts
2187                            and limited broadcast via necessary interface
2188                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2189                            This hack is not just for fun, it allows
2190                            vic,vat and friends to work.
2191                            They bind socket to loopback, set ttl to zero
2192                            and expect that it will work.
2193                            From the viewpoint of routing cache they are broken,
2194                            because we are not allowed to build multicast path
2195                            with loopback source addr (look, routing cache
2196                            cannot know, that ttl is zero, so that packet
2197                            will not leave this host and route is valid).
2198                            Luckily, this hack is good workaround.
2199                          */
2200
2201                         fl4->flowi4_oif = dev_out->ifindex;
2202                         goto make_route;
2203                 }
2204
2205                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2206                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2207                         if (!__ip_dev_find(net, fl4->saddr, false))
2208                                 goto out;
2209                 }
2210         }
2211
2212
2213         if (fl4->flowi4_oif) {
2214                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2215                 rth = ERR_PTR(-ENODEV);
2216                 if (!dev_out)
2217                         goto out;
2218
2219                 /* RACE: Check return value of inet_select_addr instead. */
2220                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2221                         rth = ERR_PTR(-ENETUNREACH);
2222                         goto out;
2223                 }
2224                 if (ipv4_is_local_multicast(fl4->daddr) ||
2225                     ipv4_is_lbcast(fl4->daddr) ||
2226                     fl4->flowi4_proto == IPPROTO_IGMP) {
2227                         if (!fl4->saddr)
2228                                 fl4->saddr = inet_select_addr(dev_out, 0,
2229                                                               RT_SCOPE_LINK);
2230                         goto make_route;
2231                 }
2232                 if (!fl4->saddr) {
2233                         if (ipv4_is_multicast(fl4->daddr))
2234                                 fl4->saddr = inet_select_addr(dev_out, 0,
2235                                                               fl4->flowi4_scope);
2236                         else if (!fl4->daddr)
2237                                 fl4->saddr = inet_select_addr(dev_out, 0,
2238                                                               RT_SCOPE_HOST);
2239                 }
2240
2241                 rth = l3mdev_get_rtable(dev_out, fl4);
2242                 if (rth)
2243                         goto out;
2244         }
2245
2246         if (!fl4->daddr) {
2247                 fl4->daddr = fl4->saddr;
2248                 if (!fl4->daddr)
2249                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2250                 dev_out = net->loopback_dev;
2251                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2252                 res.type = RTN_LOCAL;
2253                 flags |= RTCF_LOCAL;
2254                 goto make_route;
2255         }
2256
2257         err = fib_lookup(net, fl4, &res, 0);
2258         if (err) {
2259                 res.fi = NULL;
2260                 res.table = NULL;
2261                 if (fl4->flowi4_oif &&
2262                     !netif_index_is_l3_master(net, 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                 dev_out = net->loopback_dev;
2299                 fl4->flowi4_oif = dev_out->ifindex;
2300                 flags |= RTCF_LOCAL;
2301                 goto make_route;
2302         }
2303
2304         fib_select_path(net, &res, fl4, mp_hash);
2305
2306         dev_out = FIB_RES_DEV(res);
2307         fl4->flowi4_oif = dev_out->ifindex;
2308
2309
2310 make_route:
2311         rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2312
2313 out:
2314         rcu_read_unlock();
2315         return rth;
2316 }
2317 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2318
2319 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2320 {
2321         return NULL;
2322 }
2323
2324 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2325 {
2326         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2327
2328         return mtu ? : dst->dev->mtu;
2329 }
2330
2331 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2332                                           struct sk_buff *skb, u32 mtu)
2333 {
2334 }
2335
2336 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2337                                        struct sk_buff *skb)
2338 {
2339 }
2340
2341 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2342                                           unsigned long old)
2343 {
2344         return NULL;
2345 }
2346
2347 static struct dst_ops ipv4_dst_blackhole_ops = {
2348         .family                 =       AF_INET,
2349         .check                  =       ipv4_blackhole_dst_check,
2350         .mtu                    =       ipv4_blackhole_mtu,
2351         .default_advmss         =       ipv4_default_advmss,
2352         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2353         .redirect               =       ipv4_rt_blackhole_redirect,
2354         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2355         .neigh_lookup           =       ipv4_neigh_lookup,
2356 };
2357
2358 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2359 {
2360         struct rtable *ort = (struct rtable *) dst_orig;
2361         struct rtable *rt;
2362
2363         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2364         if (rt) {
2365                 struct dst_entry *new = &rt->dst;
2366
2367                 new->__use = 1;
2368                 new->input = dst_discard;
2369                 new->output = dst_discard_out;
2370
2371                 new->dev = ort->dst.dev;
2372                 if (new->dev)
2373                         dev_hold(new->dev);
2374
2375                 rt->rt_is_input = ort->rt_is_input;
2376                 rt->rt_iif = ort->rt_iif;
2377                 rt->rt_pmtu = ort->rt_pmtu;
2378
2379                 rt->rt_genid = rt_genid_ipv4(net);
2380                 rt->rt_flags = ort->rt_flags;
2381                 rt->rt_type = ort->rt_type;
2382                 rt->rt_gateway = ort->rt_gateway;
2383                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2384
2385                 INIT_LIST_HEAD(&rt->rt_uncached);
2386                 dst_free(new);
2387         }
2388
2389         dst_release(dst_orig);
2390
2391         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2392 }
2393
2394 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2395                                     const struct sock *sk)
2396 {
2397         struct rtable *rt = __ip_route_output_key(net, flp4);
2398
2399         if (IS_ERR(rt))
2400                 return rt;
2401
2402         if (flp4->flowi4_proto)
2403                 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2404                                                         flowi4_to_flowi(flp4),
2405                                                         sk, 0);
2406
2407         return rt;
2408 }
2409 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2410
2411 static int rt_fill_info(struct net *net,  __be32 dst, __be32 src, u32 table_id,
2412                         struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2413                         u32 seq, int event, int nowait, unsigned int flags)
2414 {
2415         struct rtable *rt = skb_rtable(skb);
2416         struct rtmsg *r;
2417         struct nlmsghdr *nlh;
2418         unsigned long expires = 0;
2419         u32 error;
2420         u32 metrics[RTAX_MAX];
2421
2422         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2423         if (!nlh)
2424                 return -EMSGSIZE;
2425
2426         r = nlmsg_data(nlh);
2427         r->rtm_family    = AF_INET;
2428         r->rtm_dst_len  = 32;
2429         r->rtm_src_len  = 0;
2430         r->rtm_tos      = fl4->flowi4_tos;
2431         r->rtm_table    = table_id;
2432         if (nla_put_u32(skb, RTA_TABLE, table_id))
2433                 goto nla_put_failure;
2434         r->rtm_type     = rt->rt_type;
2435         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2436         r->rtm_protocol = RTPROT_UNSPEC;
2437         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2438         if (rt->rt_flags & RTCF_NOTIFY)
2439                 r->rtm_flags |= RTM_F_NOTIFY;
2440         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2441                 r->rtm_flags |= RTCF_DOREDIRECT;
2442
2443         if (nla_put_in_addr(skb, RTA_DST, dst))
2444                 goto nla_put_failure;
2445         if (src) {
2446                 r->rtm_src_len = 32;
2447                 if (nla_put_in_addr(skb, RTA_SRC, src))
2448                         goto nla_put_failure;
2449         }
2450         if (rt->dst.dev &&
2451             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2452                 goto nla_put_failure;
2453 #ifdef CONFIG_IP_ROUTE_CLASSID
2454         if (rt->dst.tclassid &&
2455             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2456                 goto nla_put_failure;
2457 #endif
2458         if (!rt_is_input_route(rt) &&
2459             fl4->saddr != src) {
2460                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2461                         goto nla_put_failure;
2462         }
2463         if (rt->rt_uses_gateway &&
2464             nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2465                 goto nla_put_failure;
2466
2467         expires = rt->dst.expires;
2468         if (expires) {
2469                 unsigned long now = jiffies;
2470
2471                 if (time_before(now, expires))
2472                         expires -= now;
2473                 else
2474                         expires = 0;
2475         }
2476
2477         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2478         if (rt->rt_pmtu && expires)
2479                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2480         if (rtnetlink_put_metrics(skb, metrics) < 0)
2481                 goto nla_put_failure;
2482
2483         if (fl4->flowi4_mark &&
2484             nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2485                 goto nla_put_failure;
2486
2487         error = rt->dst.error;
2488
2489         if (rt_is_input_route(rt)) {
2490 #ifdef CONFIG_IP_MROUTE
2491                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2492                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2493                         int err = ipmr_get_route(net, skb,
2494                                                  fl4->saddr, fl4->daddr,
2495                                                  r, nowait);
2496                         if (err <= 0) {
2497                                 if (!nowait) {
2498                                         if (err == 0)
2499                                                 return 0;
2500                                         goto nla_put_failure;
2501                                 } else {
2502                                         if (err == -EMSGSIZE)
2503                                                 goto nla_put_failure;
2504                                         error = err;
2505                                 }
2506                         }
2507                 } else
2508 #endif
2509                         if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2510                                 goto nla_put_failure;
2511         }
2512
2513         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2514                 goto nla_put_failure;
2515
2516         nlmsg_end(skb, nlh);
2517         return 0;
2518
2519 nla_put_failure:
2520         nlmsg_cancel(skb, nlh);
2521         return -EMSGSIZE;
2522 }
2523
2524 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2525 {
2526         struct net *net = sock_net(in_skb->sk);
2527         struct rtmsg *rtm;
2528         struct nlattr *tb[RTA_MAX+1];
2529         struct rtable *rt = NULL;
2530         struct flowi4 fl4;
2531         __be32 dst = 0;
2532         __be32 src = 0;
2533         u32 iif;
2534         int err;
2535         int mark;
2536         struct sk_buff *skb;
2537         u32 table_id = RT_TABLE_MAIN;
2538
2539         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2540         if (err < 0)
2541                 goto errout;
2542
2543         rtm = nlmsg_data(nlh);
2544
2545         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2546         if (!skb) {
2547                 err = -ENOBUFS;
2548                 goto errout;
2549         }
2550
2551         /* Reserve room for dummy headers, this skb can pass
2552            through good chunk of routing engine.
2553          */
2554         skb_reset_mac_header(skb);
2555         skb_reset_network_header(skb);
2556
2557         /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2558         ip_hdr(skb)->protocol = IPPROTO_ICMP;
2559         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2560
2561         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2562         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2563         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2564         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2565
2566         memset(&fl4, 0, sizeof(fl4));
2567         fl4.daddr = dst;
2568         fl4.saddr = src;
2569         fl4.flowi4_tos = rtm->rtm_tos;
2570         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2571         fl4.flowi4_mark = mark;
2572
2573         if (netif_index_is_l3_master(net, fl4.flowi4_oif))
2574                 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF;
2575
2576         if (iif) {
2577                 struct net_device *dev;
2578
2579                 dev = __dev_get_by_index(net, iif);
2580                 if (!dev) {
2581                         err = -ENODEV;
2582                         goto errout_free;
2583                 }
2584
2585                 skb->protocol   = htons(ETH_P_IP);
2586                 skb->dev        = dev;
2587                 skb->mark       = mark;
2588                 local_bh_disable();
2589                 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2590                 local_bh_enable();
2591
2592                 rt = skb_rtable(skb);
2593                 if (err == 0 && rt->dst.error)
2594                         err = -rt->dst.error;
2595         } else {
2596                 rt = ip_route_output_key(net, &fl4);
2597
2598                 err = 0;
2599                 if (IS_ERR(rt))
2600                         err = PTR_ERR(rt);
2601         }
2602
2603         if (err)
2604                 goto errout_free;
2605
2606         skb_dst_set(skb, &rt->dst);
2607         if (rtm->rtm_flags & RTM_F_NOTIFY)
2608                 rt->rt_flags |= RTCF_NOTIFY;
2609
2610         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2611                 table_id = rt->rt_table_id;
2612
2613         err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2614                            NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2615                            RTM_NEWROUTE, 0, 0);
2616         if (err < 0)
2617                 goto errout_free;
2618
2619         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2620 errout:
2621         return err;
2622
2623 errout_free:
2624         kfree_skb(skb);
2625         goto errout;
2626 }
2627
2628 void ip_rt_multicast_event(struct in_device *in_dev)
2629 {
2630         rt_cache_flush(dev_net(in_dev->dev));
2631 }
2632
2633 #ifdef CONFIG_SYSCTL
2634 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
2635 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
2636 static int ip_rt_gc_elasticity __read_mostly    = 8;
2637
2638 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2639                                         void __user *buffer,
2640                                         size_t *lenp, loff_t *ppos)
2641 {
2642         struct net *net = (struct net *)__ctl->extra1;
2643
2644         if (write) {
2645                 rt_cache_flush(net);
2646                 fnhe_genid_bump(net);
2647                 return 0;
2648         }
2649
2650         return -EINVAL;
2651 }
2652
2653 static struct ctl_table ipv4_route_table[] = {
2654         {
2655                 .procname       = "gc_thresh",
2656                 .data           = &ipv4_dst_ops.gc_thresh,
2657                 .maxlen         = sizeof(int),
2658                 .mode           = 0644,
2659                 .proc_handler   = proc_dointvec,
2660         },
2661         {
2662                 .procname       = "max_size",
2663                 .data           = &ip_rt_max_size,
2664                 .maxlen         = sizeof(int),
2665                 .mode           = 0644,
2666                 .proc_handler   = proc_dointvec,
2667         },
2668         {
2669                 /*  Deprecated. Use gc_min_interval_ms */
2670
2671                 .procname       = "gc_min_interval",
2672                 .data           = &ip_rt_gc_min_interval,
2673                 .maxlen         = sizeof(int),
2674                 .mode           = 0644,
2675                 .proc_handler   = proc_dointvec_jiffies,
2676         },
2677         {
2678                 .procname       = "gc_min_interval_ms",
2679                 .data           = &ip_rt_gc_min_interval,
2680                 .maxlen         = sizeof(int),
2681                 .mode           = 0644,
2682                 .proc_handler   = proc_dointvec_ms_jiffies,
2683         },
2684         {
2685                 .procname       = "gc_timeout",
2686                 .data           = &ip_rt_gc_timeout,
2687                 .maxlen         = sizeof(int),
2688                 .mode           = 0644,
2689                 .proc_handler   = proc_dointvec_jiffies,
2690         },
2691         {
2692                 .procname       = "gc_interval",
2693                 .data           = &ip_rt_gc_interval,
2694                 .maxlen         = sizeof(int),
2695                 .mode           = 0644,
2696                 .proc_handler   = proc_dointvec_jiffies,
2697         },
2698         {
2699                 .procname       = "redirect_load",
2700                 .data           = &ip_rt_redirect_load,
2701                 .maxlen         = sizeof(int),
2702                 .mode           = 0644,
2703                 .proc_handler   = proc_dointvec,
2704         },
2705         {
2706                 .procname       = "redirect_number",
2707                 .data           = &ip_rt_redirect_number,
2708                 .maxlen         = sizeof(int),
2709                 .mode           = 0644,
2710                 .proc_handler   = proc_dointvec,
2711         },
2712         {
2713                 .procname       = "redirect_silence",
2714                 .data           = &ip_rt_redirect_silence,
2715                 .maxlen         = sizeof(int),
2716                 .mode           = 0644,
2717                 .proc_handler   = proc_dointvec,
2718         },
2719         {
2720                 .procname       = "error_cost",
2721                 .data           = &ip_rt_error_cost,
2722                 .maxlen         = sizeof(int),
2723                 .mode           = 0644,
2724                 .proc_handler   = proc_dointvec,
2725         },
2726         {
2727                 .procname       = "error_burst",
2728                 .data           = &ip_rt_error_burst,
2729                 .maxlen         = sizeof(int),
2730                 .mode           = 0644,
2731                 .proc_handler   = proc_dointvec,
2732         },
2733         {
2734                 .procname       = "gc_elasticity",
2735                 .data           = &ip_rt_gc_elasticity,
2736                 .maxlen         = sizeof(int),
2737                 .mode           = 0644,
2738                 .proc_handler   = proc_dointvec,
2739         },
2740         {
2741                 .procname       = "mtu_expires",
2742                 .data           = &ip_rt_mtu_expires,
2743                 .maxlen         = sizeof(int),
2744                 .mode           = 0644,
2745                 .proc_handler   = proc_dointvec_jiffies,
2746         },
2747         {
2748                 .procname       = "min_pmtu",
2749                 .data           = &ip_rt_min_pmtu,
2750                 .maxlen         = sizeof(int),
2751                 .mode           = 0644,
2752                 .proc_handler   = proc_dointvec,
2753         },
2754         {
2755                 .procname       = "min_adv_mss",
2756                 .data           = &ip_rt_min_advmss,
2757                 .maxlen         = sizeof(int),
2758                 .mode           = 0644,
2759                 .proc_handler   = proc_dointvec,
2760         },
2761         { }
2762 };
2763
2764 static struct ctl_table ipv4_route_flush_table[] = {
2765         {
2766                 .procname       = "flush",
2767                 .maxlen         = sizeof(int),
2768                 .mode           = 0200,
2769                 .proc_handler   = ipv4_sysctl_rtcache_flush,
2770         },
2771         { },
2772 };
2773
2774 static __net_init int sysctl_route_net_init(struct net *net)
2775 {
2776         struct ctl_table *tbl;
2777
2778         tbl = ipv4_route_flush_table;
2779         if (!net_eq(net, &init_net)) {
2780                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2781                 if (!tbl)
2782                         goto err_dup;
2783
2784                 /* Don't export sysctls to unprivileged users */
2785                 if (net->user_ns != &init_user_ns)
2786                         tbl[0].procname = NULL;
2787         }
2788         tbl[0].extra1 = net;
2789
2790         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2791         if (!net->ipv4.route_hdr)
2792                 goto err_reg;
2793         return 0;
2794
2795 err_reg:
2796         if (tbl != ipv4_route_flush_table)
2797                 kfree(tbl);
2798 err_dup:
2799         return -ENOMEM;
2800 }
2801
2802 static __net_exit void sysctl_route_net_exit(struct net *net)
2803 {
2804         struct ctl_table *tbl;
2805
2806         tbl = net->ipv4.route_hdr->ctl_table_arg;
2807         unregister_net_sysctl_table(net->ipv4.route_hdr);
2808         BUG_ON(tbl == ipv4_route_flush_table);
2809         kfree(tbl);
2810 }
2811
2812 static __net_initdata struct pernet_operations sysctl_route_ops = {
2813         .init = sysctl_route_net_init,
2814         .exit = sysctl_route_net_exit,
2815 };
2816 #endif
2817
2818 static __net_init int rt_genid_init(struct net *net)
2819 {
2820         atomic_set(&net->ipv4.rt_genid, 0);
2821         atomic_set(&net->fnhe_genid, 0);
2822         get_random_bytes(&net->ipv4.dev_addr_genid,
2823                          sizeof(net->ipv4.dev_addr_genid));
2824         return 0;
2825 }
2826
2827 static __net_initdata struct pernet_operations rt_genid_ops = {
2828         .init = rt_genid_init,
2829 };
2830
2831 static int __net_init ipv4_inetpeer_init(struct net *net)
2832 {
2833         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2834
2835         if (!bp)
2836                 return -ENOMEM;
2837         inet_peer_base_init(bp);
2838         net->ipv4.peers = bp;
2839         return 0;
2840 }
2841
2842 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2843 {
2844         struct inet_peer_base *bp = net->ipv4.peers;
2845
2846         net->ipv4.peers = NULL;
2847         inetpeer_invalidate_tree(bp);
2848         kfree(bp);
2849 }
2850
2851 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2852         .init   =       ipv4_inetpeer_init,
2853         .exit   =       ipv4_inetpeer_exit,
2854 };
2855
2856 #ifdef CONFIG_IP_ROUTE_CLASSID
2857 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2858 #endif /* CONFIG_IP_ROUTE_CLASSID */
2859
2860 int __init ip_rt_init(void)
2861 {
2862         int rc = 0;
2863         int cpu;
2864
2865         ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2866         if (!ip_idents)
2867                 panic("IP: failed to allocate ip_idents\n");
2868
2869         prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2870
2871         ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2872         if (!ip_tstamps)
2873                 panic("IP: failed to allocate ip_tstamps\n");
2874
2875         for_each_possible_cpu(cpu) {
2876                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2877
2878                 INIT_LIST_HEAD(&ul->head);
2879                 spin_lock_init(&ul->lock);
2880         }
2881 #ifdef CONFIG_IP_ROUTE_CLASSID
2882         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2883         if (!ip_rt_acct)
2884                 panic("IP: failed to allocate ip_rt_acct\n");
2885 #endif
2886
2887         ipv4_dst_ops.kmem_cachep =
2888                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2889                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2890
2891         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2892
2893         if (dst_entries_init(&ipv4_dst_ops) < 0)
2894                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2895
2896         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2897                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2898
2899         ipv4_dst_ops.gc_thresh = ~0;
2900         ip_rt_max_size = INT_MAX;
2901
2902         devinet_init();
2903         ip_fib_init();
2904
2905         if (ip_rt_proc_init())
2906                 pr_err("Unable to create route proc files\n");
2907 #ifdef CONFIG_XFRM
2908         xfrm_init();
2909         xfrm4_init();
2910 #endif
2911         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2912
2913 #ifdef CONFIG_SYSCTL
2914         register_pernet_subsys(&sysctl_route_ops);
2915 #endif
2916         register_pernet_subsys(&rt_genid_ops);
2917         register_pernet_subsys(&ipv4_inetpeer_ops);
2918         return rc;
2919 }
2920
2921 #ifdef CONFIG_SYSCTL
2922 /*
2923  * We really need to sanitize the damn ipv4 init order, then all
2924  * this nonsense will go away.
2925  */
2926 void __init ip_static_sysctl_init(void)
2927 {
2928         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2929 }
2930 #endif