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