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 <linux/uaccess.h>
  69 #include <linux/bitops.h>
  70 #include <linux/types.h>
  71 #include <linux/kernel.h>
  72 #include <linux/mm.h>
  73 #include <linux/string.h>
  74 #include <linux/socket.h>
  75 #include <linux/sockios.h>
  76 #include <linux/errno.h>
  77 #include <linux/in.h>
  78 #include <linux/inet.h>
  79 #include <linux/netdevice.h>
  80 #include <linux/proc_fs.h>
  81 #include <linux/init.h>
  82 #include <linux/skbuff.h>
  83 #include <linux/inetdevice.h>
  84 #include <linux/igmp.h>
  85 #include <linux/pkt_sched.h>
  86 #include <linux/mroute.h>
  87 #include <linux/netfilter_ipv4.h>
  88 #include <linux/random.h>
  89 #include <linux/rcupdate.h>
  90 #include <linux/times.h>
  91 #include <linux/slab.h>
  92 #include <linux/jhash.h>
  93 #include <net/dst.h>
  94 #include <net/dst_metadata.h>
  95 #include <net/net_namespace.h>
  96 #include <net/protocol.h>
  97 #include <net/ip.h>
  98 #include <net/route.h>
  99 #include <net/inetpeer.h>
 100 #include <net/sock.h>
 101 #include <net/ip_fib.h>
 102 #include <net/arp.h>
 103 #include <net/tcp.h>
 104 #include <net/icmp.h>
 105 #include <net/xfrm.h>
 106 #include <net/lwtunnel.h>
 107 #include <net/netevent.h>
 108 #include <net/rtnetlink.h>
 109 #ifdef CONFIG_SYSCTL
 110 #include <linux/sysctl.h>
 111 #include <linux/kmemleak.h>
 112 #endif
 113 #include <net/secure_seq.h>
 114 #include <net/ip_tunnels.h>
 115 #include <net/l3mdev.h>
 116
 117 #include "fib_lookup.h"
 118
 119 #define RT_FL_TOS(oldflp4) \
 120         ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
 121
 122 #define RT_GC_TIMEOUT (300*HZ)
 123
 124 static int ip_rt_max_size;
 125 static int ip_rt_redirect_number __read_mostly  = 9;
 126 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 127 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 128 static int ip_rt_error_cost __read_mostly       = HZ;
 129 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 130 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
 131 static u32 ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
 132 static int ip_rt_min_advmss __read_mostly       = 256;
 133
 134 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 135
 136 /*
 137  *      Interface to generic destination cache.
 138  */
 139
 140 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 141 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 142 static unsigned int      ipv4_mtu(const struct dst_entry *dst);
 143 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
 144 static void              ipv4_link_failure(struct sk_buff *skb);
 145 static void              ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 146                                            struct sk_buff *skb, u32 mtu);
 147 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
 148                                         struct sk_buff *skb);
 149 static void             ipv4_dst_destroy(struct dst_entry *dst);
 150
 151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 152 {
 153         WARN_ON(1);
 154         return NULL;
 155 }
 156
 157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 158                                            struct sk_buff *skb,
 159                                            const void *daddr);
 160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
 161
 162 static struct dst_ops ipv4_dst_ops = {
 163         .family =               AF_INET,
 164         .check =                ipv4_dst_check,
 165         .default_advmss =       ipv4_default_advmss,
 166         .mtu =                  ipv4_mtu,
 167         .cow_metrics =          ipv4_cow_metrics,
 168         .destroy =              ipv4_dst_destroy,
 169         .negative_advice =      ipv4_negative_advice,
 170         .link_failure =         ipv4_link_failure,
 171         .update_pmtu =          ip_rt_update_pmtu,
 172         .redirect =             ip_do_redirect,
 173         .local_out =            __ip_local_out,
 174         .neigh_lookup =         ipv4_neigh_lookup,
 175         .confirm_neigh =        ipv4_confirm_neigh,
 176 };
 177
 178 #define ECN_OR_COST(class)      TC_PRIO_##class
 179
 180 const __u8 ip_tos2prio[16] = {
 181         TC_PRIO_BESTEFFORT,
 182         ECN_OR_COST(BESTEFFORT),
 183         TC_PRIO_BESTEFFORT,
 184         ECN_OR_COST(BESTEFFORT),
 185         TC_PRIO_BULK,
 186         ECN_OR_COST(BULK),
 187         TC_PRIO_BULK,
 188         ECN_OR_COST(BULK),
 189         TC_PRIO_INTERACTIVE,
 190         ECN_OR_COST(INTERACTIVE),
 191         TC_PRIO_INTERACTIVE,
 192         ECN_OR_COST(INTERACTIVE),
 193         TC_PRIO_INTERACTIVE_BULK,
 194         ECN_OR_COST(INTERACTIVE_BULK),
 195         TC_PRIO_INTERACTIVE_BULK,
 196         ECN_OR_COST(INTERACTIVE_BULK)
 197 };
 198 EXPORT_SYMBOL(ip_tos2prio);
 199
 200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
 202
 203 #ifdef CONFIG_PROC_FS
 204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 205 {
 206         if (*pos)
 207                 return NULL;
 208         return SEQ_START_TOKEN;
 209 }
 210
 211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 212 {
 213         ++*pos;
 214         return NULL;
 215 }
 216
 217 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 218 {
 219 }
 220
 221 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 222 {
 223         if (v == SEQ_START_TOKEN)
 224                 seq_printf(seq, "%-127s\n",
 225                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 226                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 227                            "HHUptod\tSpecDst");
 228         return 0;
 229 }
 230
 231 static const struct seq_operations rt_cache_seq_ops = {
 232         .start  = rt_cache_seq_start,
 233         .next   = rt_cache_seq_next,
 234         .stop   = rt_cache_seq_stop,
 235         .show   = rt_cache_seq_show,
 236 };
 237
 238 static int rt_cache_seq_open(struct inode *inode, struct file *file)
 239 {
 240         return seq_open(file, &rt_cache_seq_ops);
 241 }
 242
 243 static const struct file_operations rt_cache_seq_fops = {
 244         .open    = rt_cache_seq_open,
 245         .read    = seq_read,
 246         .llseek  = seq_lseek,
 247         .release = seq_release,
 248 };
 249
 250
 251 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 252 {
 253         int cpu;
 254
 255         if (*pos == 0)
 256                 return SEQ_START_TOKEN;
 257
 258         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 259                 if (!cpu_possible(cpu))
 260                         continue;
 261                 *pos = cpu+1;
 262                 return &per_cpu(rt_cache_stat, cpu);
 263         }
 264         return NULL;
 265 }
 266
 267 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 268 {
 269         int cpu;
 270
 271         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 272                 if (!cpu_possible(cpu))
 273                         continue;
 274                 *pos = cpu+1;
 275                 return &per_cpu(rt_cache_stat, cpu);
 276         }
 277         return NULL;
 278
 279 }
 280
 281 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 282 {
 283
 284 }
 285
 286 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 287 {
 288         struct rt_cache_stat *st = v;
 289
 290         if (v == SEQ_START_TOKEN) {
 291                 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");
 292                 return 0;
 293         }
 294
 295         seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 296                    " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
 297                    dst_entries_get_slow(&ipv4_dst_ops),
 298                    0, /* st->in_hit */
 299                    st->in_slow_tot,
 300                    st->in_slow_mc,
 301                    st->in_no_route,
 302                    st->in_brd,
 303                    st->in_martian_dst,
 304                    st->in_martian_src,
 305
 306                    0, /* st->out_hit */
 307                    st->out_slow_tot,
 308                    st->out_slow_mc,
 309
 310                    0, /* st->gc_total */
 311                    0, /* st->gc_ignored */
 312                    0, /* st->gc_goal_miss */
 313                    0, /* st->gc_dst_overflow */
 314                    0, /* st->in_hlist_search */
 315                    0  /* st->out_hlist_search */
 316                 );
 317         return 0;
 318 }
 319
 320 static const struct seq_operations rt_cpu_seq_ops = {
 321         .start  = rt_cpu_seq_start,
 322         .next   = rt_cpu_seq_next,
 323         .stop   = rt_cpu_seq_stop,
 324         .show   = rt_cpu_seq_show,
 325 };
 326
 327
 328 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 329 {
 330         return seq_open(file, &rt_cpu_seq_ops);
 331 }
 332
 333 static const struct file_operations rt_cpu_seq_fops = {
 334         .open    = rt_cpu_seq_open,
 335         .read    = seq_read,
 336         .llseek  = seq_lseek,
 337         .release = seq_release,
 338 };
 339
 340 #ifdef CONFIG_IP_ROUTE_CLASSID
 341 static int rt_acct_proc_show(struct seq_file *m, void *v)
 342 {
 343         struct ip_rt_acct *dst, *src;
 344         unsigned int i, j;
 345
 346         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 347         if (!dst)
 348                 return -ENOMEM;
 349
 350         for_each_possible_cpu(i) {
 351                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 352                 for (j = 0; j < 256; j++) {
 353                         dst[j].o_bytes   += src[j].o_bytes;
 354                         dst[j].o_packets += src[j].o_packets;
 355                         dst[j].i_bytes   += src[j].i_bytes;
 356                         dst[j].i_packets += src[j].i_packets;
 357                 }
 358         }
 359
 360         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 361         kfree(dst);
 362         return 0;
 363 }
 364
 365 static int rt_acct_proc_open(struct inode *inode, struct file *file)
 366 {
 367         return single_open(file, rt_acct_proc_show, NULL);
 368 }
 369
 370 static const struct file_operations rt_acct_proc_fops = {
 371         .open           = rt_acct_proc_open,
 372         .read           = seq_read,
 373         .llseek         = seq_lseek,
 374         .release        = single_release,
 375 };
 376 #endif
 377
 378 static int __net_init ip_rt_do_proc_init(struct net *net)
 379 {
 380         struct proc_dir_entry *pde;
 381
 382         pde = proc_create("rt_cache", 0444, net->proc_net,
 383                           &rt_cache_seq_fops);
 384         if (!pde)
 385                 goto err1;
 386
 387         pde = proc_create("rt_cache", 0444,
 388                           net->proc_net_stat, &rt_cpu_seq_fops);
 389         if (!pde)
 390                 goto err2;
 391
 392 #ifdef CONFIG_IP_ROUTE_CLASSID
 393         pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
 394         if (!pde)
 395                 goto err3;
 396 #endif
 397         return 0;
 398
 399 #ifdef CONFIG_IP_ROUTE_CLASSID
 400 err3:
 401         remove_proc_entry("rt_cache", net->proc_net_stat);
 402 #endif
 403 err2:
 404         remove_proc_entry("rt_cache", net->proc_net);
 405 err1:
 406         return -ENOMEM;
 407 }
 408
 409 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 410 {
 411         remove_proc_entry("rt_cache", net->proc_net_stat);
 412         remove_proc_entry("rt_cache", net->proc_net);
 413 #ifdef CONFIG_IP_ROUTE_CLASSID
 414         remove_proc_entry("rt_acct", net->proc_net);
 415 #endif
 416 }
 417
 418 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 419         .init = ip_rt_do_proc_init,
 420         .exit = ip_rt_do_proc_exit,
 421 };
 422
 423 static int __init ip_rt_proc_init(void)
 424 {
 425         return register_pernet_subsys(&ip_rt_proc_ops);
 426 }
 427
 428 #else
 429 static inline int ip_rt_proc_init(void)
 430 {
 431         return 0;
 432 }
 433 #endif /* CONFIG_PROC_FS */
 434
 435 static inline bool rt_is_expired(const struct rtable *rth)
 436 {
 437         return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
 438 }
 439
 440 void rt_cache_flush(struct net *net)
 441 {
 442         rt_genid_bump_ipv4(net);
 443 }
 444
 445 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 446                                            struct sk_buff *skb,
 447                                            const void *daddr)
 448 {
 449         struct net_device *dev = dst->dev;
 450         const __be32 *pkey = daddr;
 451         const struct rtable *rt;
 452         struct neighbour *n;
 453
 454         rt = (const struct rtable *) dst;
 455         if (rt->rt_gateway)
 456                 pkey = (const __be32 *) &rt->rt_gateway;
 457         else if (skb)
 458                 pkey = &ip_hdr(skb)->daddr;
 459
 460         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
 461         if (n)
 462                 return n;
 463         return neigh_create(&arp_tbl, pkey, dev);
 464 }
 465
 466 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 467 {
 468         struct net_device *dev = dst->dev;
 469         const __be32 *pkey = daddr;
 470         const struct rtable *rt;
 471
 472         rt = (const struct rtable *)dst;
 473         if (rt->rt_gateway)
 474                 pkey = (const __be32 *)&rt->rt_gateway;
 475         else if (!daddr ||
 476                  (rt->rt_flags &
 477                   (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
 478                 return;
 479
 480         __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
 481 }
 482
 483 #define IP_IDENTS_SZ 2048u
 484
 485 static atomic_t *ip_idents __read_mostly;
 486 static u32 *ip_tstamps __read_mostly;
 487
 488 /* In order to protect privacy, we add a perturbation to identifiers
 489  * if one generator is seldom used. This makes hard for an attacker
 490  * to infer how many packets were sent between two points in time.
 491  */
 492 u32 ip_idents_reserve(u32 hash, int segs)
 493 {
 494         u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
 495         atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
 496         u32 old = READ_ONCE(*p_tstamp);
 497         u32 now = (u32)jiffies;
 498         u32 new, delta = 0;
 499
 500         if (old != now && cmpxchg(p_tstamp, old, now) == old)
 501                 delta = prandom_u32_max(now - old);
 502
 503         /* Do not use atomic_add_return() as it makes UBSAN unhappy */
 504         do {
 505                 old = (u32)atomic_read(p_id);
 506                 new = old + delta + segs;
 507         } while (atomic_cmpxchg(p_id, old, new) != old);
 508
 509         return new - segs;
 510 }
 511 EXPORT_SYMBOL(ip_idents_reserve);
 512
 513 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
 514 {
 515         static u32 ip_idents_hashrnd __read_mostly;
 516         u32 hash, id;
 517
 518         net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
 519
 520         hash = jhash_3words((__force u32)iph->daddr,
 521                             (__force u32)iph->saddr,
 522                             iph->protocol ^ net_hash_mix(net),
 523                             ip_idents_hashrnd);
 524         id = ip_idents_reserve(hash, segs);
 525         iph->id = htons(id);
 526 }
 527 EXPORT_SYMBOL(__ip_select_ident);
 528
 529 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
 530                              const struct sock *sk,
 531                              const struct iphdr *iph,
 532                              int oif, u8 tos,
 533                              u8 prot, u32 mark, int flow_flags)
 534 {
 535         if (sk) {
 536                 const struct inet_sock *inet = inet_sk(sk);
 537
 538                 oif = sk->sk_bound_dev_if;
 539                 mark = sk->sk_mark;
 540                 tos = RT_CONN_FLAGS(sk);
 541                 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
 542         }
 543         flowi4_init_output(fl4, oif, mark, tos,
 544                            RT_SCOPE_UNIVERSE, prot,
 545                            flow_flags,
 546                            iph->daddr, iph->saddr, 0, 0,
 547                            sock_net_uid(net, sk));
 548 }
 549
 550 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
 551                                const struct sock *sk)
 552 {
 553         const struct net *net = dev_net(skb->dev);
 554         const struct iphdr *iph = ip_hdr(skb);
 555         int oif = skb->dev->ifindex;
 556         u8 tos = RT_TOS(iph->tos);
 557         u8 prot = iph->protocol;
 558         u32 mark = skb->mark;
 559
 560         __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
 561 }
 562
 563 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
 564 {
 565         const struct inet_sock *inet = inet_sk(sk);
 566         const struct ip_options_rcu *inet_opt;
 567         __be32 daddr = inet->inet_daddr;
 568
 569         rcu_read_lock();
 570         inet_opt = rcu_dereference(inet->inet_opt);
 571         if (inet_opt && inet_opt->opt.srr)
 572                 daddr = inet_opt->opt.faddr;
 573         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
 574                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
 575                            inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
 576                            inet_sk_flowi_flags(sk),
 577                            daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
 578         rcu_read_unlock();
 579 }
 580
 581 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
 582                                  const struct sk_buff *skb)
 583 {
 584         if (skb)
 585                 build_skb_flow_key(fl4, skb, sk);
 586         else
 587                 build_sk_flow_key(fl4, sk);
 588 }
 589
 590 static DEFINE_SPINLOCK(fnhe_lock);
 591
 592 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
 593 {
 594         struct rtable *rt;
 595
 596         rt = rcu_dereference(fnhe->fnhe_rth_input);
 597         if (rt) {
 598                 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
 599                 dst_dev_put(&rt->dst);
 600                 dst_release(&rt->dst);
 601         }
 602         rt = rcu_dereference(fnhe->fnhe_rth_output);
 603         if (rt) {
 604                 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
 605                 dst_dev_put(&rt->dst);
 606                 dst_release(&rt->dst);
 607         }
 608 }
 609
 610 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
 611 {
 612         struct fib_nh_exception *fnhe, *oldest;
 613
 614         oldest = rcu_dereference(hash->chain);
 615         for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
 616              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 617                 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
 618                         oldest = fnhe;
 619         }
 620         fnhe_flush_routes(oldest);
 621         return oldest;
 622 }
 623
 624 static inline u32 fnhe_hashfun(__be32 daddr)
 625 {
 626         static u32 fnhe_hashrnd __read_mostly;
 627         u32 hval;
 628
 629         net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
 630         hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
 631         return hash_32(hval, FNHE_HASH_SHIFT);
 632 }
 633
 634 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
 635 {
 636         rt->rt_pmtu = fnhe->fnhe_pmtu;
 637         rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
 638         rt->dst.expires = fnhe->fnhe_expires;
 639
 640         if (fnhe->fnhe_gw) {
 641                 rt->rt_flags |= RTCF_REDIRECTED;
 642                 rt->rt_gateway = fnhe->fnhe_gw;
 643                 rt->rt_uses_gateway = 1;
 644         }
 645 }
 646
 647 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
 648                                   u32 pmtu, bool lock, unsigned long expires)
 649 {
 650         struct fnhe_hash_bucket *hash;
 651         struct fib_nh_exception *fnhe;
 652         struct rtable *rt;
 653         u32 genid, hval;
 654         unsigned int i;
 655         int depth;
 656
 657         genid = fnhe_genid(dev_net(nh->nh_dev));
 658         hval = fnhe_hashfun(daddr);
 659
 660         spin_lock_bh(&fnhe_lock);
 661
 662         hash = rcu_dereference(nh->nh_exceptions);
 663         if (!hash) {
 664                 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
 665                 if (!hash)
 666                         goto out_unlock;
 667                 rcu_assign_pointer(nh->nh_exceptions, hash);
 668         }
 669
 670         hash += hval;
 671
 672         depth = 0;
 673         for (fnhe = rcu_dereference(hash->chain); fnhe;
 674              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 675                 if (fnhe->fnhe_daddr == daddr)
 676                         break;
 677                 depth++;
 678         }
 679
 680         if (fnhe) {
 681                 if (fnhe->fnhe_genid != genid)
 682                         fnhe->fnhe_genid = genid;
 683                 if (gw)
 684                         fnhe->fnhe_gw = gw;
 685                 if (pmtu) {
 686                         fnhe->fnhe_pmtu = pmtu;
 687                         fnhe->fnhe_mtu_locked = lock;
 688                 }
 689                 fnhe->fnhe_expires = max(1UL, expires);
 690                 /* Update all cached dsts too */
 691                 rt = rcu_dereference(fnhe->fnhe_rth_input);
 692                 if (rt)
 693                         fill_route_from_fnhe(rt, fnhe);
 694                 rt = rcu_dereference(fnhe->fnhe_rth_output);
 695                 if (rt)
 696                         fill_route_from_fnhe(rt, fnhe);
 697         } else {
 698                 if (depth > FNHE_RECLAIM_DEPTH)
 699                         fnhe = fnhe_oldest(hash);
 700                 else {
 701                         fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
 702                         if (!fnhe)
 703                                 goto out_unlock;
 704
 705                         fnhe->fnhe_next = hash->chain;
 706                         rcu_assign_pointer(hash->chain, fnhe);
 707                 }
 708                 fnhe->fnhe_genid = genid;
 709                 fnhe->fnhe_daddr = daddr;
 710                 fnhe->fnhe_gw = gw;
 711                 fnhe->fnhe_pmtu = pmtu;
 712                 fnhe->fnhe_mtu_locked = lock;
 713                 fnhe->fnhe_expires = expires;
 714
 715                 /* Exception created; mark the cached routes for the nexthop
 716                  * stale, so anyone caching it rechecks if this exception
 717                  * applies to them.
 718                  */
 719                 rt = rcu_dereference(nh->nh_rth_input);
 720                 if (rt)
 721                         rt->dst.obsolete = DST_OBSOLETE_KILL;
 722
 723                 for_each_possible_cpu(i) {
 724                         struct rtable __rcu **prt;
 725                         prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
 726                         rt = rcu_dereference(*prt);
 727                         if (rt)
 728                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 729                 }
 730         }
 731
 732         fnhe->fnhe_stamp = jiffies;
 733
 734 out_unlock:
 735         spin_unlock_bh(&fnhe_lock);
 736 }
 737
 738 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 739                              bool kill_route)
 740 {
 741         __be32 new_gw = icmp_hdr(skb)->un.gateway;
 742         __be32 old_gw = ip_hdr(skb)->saddr;
 743         struct net_device *dev = skb->dev;
 744         struct in_device *in_dev;
 745         struct fib_result res;
 746         struct neighbour *n;
 747         struct net *net;
 748
 749         switch (icmp_hdr(skb)->code & 7) {
 750         case ICMP_REDIR_NET:
 751         case ICMP_REDIR_NETTOS:
 752         case ICMP_REDIR_HOST:
 753         case ICMP_REDIR_HOSTTOS:
 754                 break;
 755
 756         default:
 757                 return;
 758         }
 759
 760         if (rt->rt_gateway != old_gw)
 761                 return;
 762
 763         in_dev = __in_dev_get_rcu(dev);
 764         if (!in_dev)
 765                 return;
 766
 767         net = dev_net(dev);
 768         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
 769             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
 770             ipv4_is_zeronet(new_gw))
 771                 goto reject_redirect;
 772
 773         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
 774                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
 775                         goto reject_redirect;
 776                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
 777                         goto reject_redirect;
 778         } else {
 779                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
 780                         goto reject_redirect;
 781         }
 782
 783         n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
 784         if (!n)
 785                 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
 786         if (!IS_ERR(n)) {
 787                 if (!(n->nud_state & NUD_VALID)) {
 788                         neigh_event_send(n, NULL);
 789                 } else {
 790                         if (fib_lookup(net, fl4, &res, 0) == 0) {
 791                                 struct fib_nh *nh = &FIB_RES_NH(res);
 792
 793                                 update_or_create_fnhe(nh, fl4->daddr, new_gw,
 794                                                 0, false,
 795                                                 jiffies + ip_rt_gc_timeout);
 796                         }
 797                         if (kill_route)
 798                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 799                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 800                 }
 801                 neigh_release(n);
 802         }
 803         return;
 804
 805 reject_redirect:
 806 #ifdef CONFIG_IP_ROUTE_VERBOSE
 807         if (IN_DEV_LOG_MARTIANS(in_dev)) {
 808                 const struct iphdr *iph = (const struct iphdr *) skb->data;
 809                 __be32 daddr = iph->daddr;
 810                 __be32 saddr = iph->saddr;
 811
 812                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
 813                                      "  Advised path = %pI4 -> %pI4\n",
 814                                      &old_gw, dev->name, &new_gw,
 815                                      &saddr, &daddr);
 816         }
 817 #endif
 818         ;
 819 }
 820
 821 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
 822 {
 823         struct rtable *rt;
 824         struct flowi4 fl4;
 825         const struct iphdr *iph = (const struct iphdr *) skb->data;
 826         struct net *net = dev_net(skb->dev);
 827         int oif = skb->dev->ifindex;
 828         u8 tos = RT_TOS(iph->tos);
 829         u8 prot = iph->protocol;
 830         u32 mark = skb->mark;
 831
 832         rt = (struct rtable *) dst;
 833
 834         __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
 835         __ip_do_redirect(rt, skb, &fl4, true);
 836 }
 837
 838 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 839 {
 840         struct rtable *rt = (struct rtable *)dst;
 841         struct dst_entry *ret = dst;
 842
 843         if (rt) {
 844                 if (dst->obsolete > 0) {
 845                         ip_rt_put(rt);
 846                         ret = NULL;
 847                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
 848                            rt->dst.expires) {
 849                         ip_rt_put(rt);
 850                         ret = NULL;
 851                 }
 852         }
 853         return ret;
 854 }
 855
 856 /*
 857  * Algorithm:
 858  *      1. The first ip_rt_redirect_number redirects are sent
 859  *         with exponential backoff, then we stop sending them at all,
 860  *         assuming that the host ignores our redirects.
 861  *      2. If we did not see packets requiring redirects
 862  *         during ip_rt_redirect_silence, we assume that the host
 863  *         forgot redirected route and start to send redirects again.
 864  *
 865  * This algorithm is much cheaper and more intelligent than dumb load limiting
 866  * in icmp.c.
 867  *
 868  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 869  * and "frag. need" (breaks PMTU discovery) in icmp.c.
 870  */
 871
 872 void ip_rt_send_redirect(struct sk_buff *skb)
 873 {
 874         struct rtable *rt = skb_rtable(skb);
 875         struct in_device *in_dev;
 876         struct inet_peer *peer;
 877         struct net *net;
 878         int log_martians;
 879         int vif;
 880
 881         rcu_read_lock();
 882         in_dev = __in_dev_get_rcu(rt->dst.dev);
 883         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
 884                 rcu_read_unlock();
 885                 return;
 886         }
 887         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
 888         vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
 889         rcu_read_unlock();
 890
 891         net = dev_net(rt->dst.dev);
 892         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
 893         if (!peer) {
 894                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
 895                           rt_nexthop(rt, ip_hdr(skb)->daddr));
 896                 return;
 897         }
 898
 899         /* No redirected packets during ip_rt_redirect_silence;
 900          * reset the algorithm.
 901          */
 902         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
 903                 peer->rate_tokens = 0;
 904
 905         /* Too many ignored redirects; do not send anything
 906          * set dst.rate_last to the last seen redirected packet.
 907          */
 908         if (peer->rate_tokens >= ip_rt_redirect_number) {
 909                 peer->rate_last = jiffies;
 910                 goto out_put_peer;
 911         }
 912
 913         /* Check for load limit; set rate_last to the latest sent
 914          * redirect.
 915          */
 916         if (peer->rate_tokens == 0 ||
 917             time_after(jiffies,
 918                        (peer->rate_last +
 919                         (ip_rt_redirect_load << peer->rate_tokens)))) {
 920                 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
 921
 922                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 923                 peer->rate_last = jiffies;
 924                 ++peer->rate_tokens;
 925 #ifdef CONFIG_IP_ROUTE_VERBOSE
 926                 if (log_martians &&
 927                     peer->rate_tokens == ip_rt_redirect_number)
 928                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 929                                              &ip_hdr(skb)->saddr, inet_iif(skb),
 930                                              &ip_hdr(skb)->daddr, &gw);
 931 #endif
 932         }
 933 out_put_peer:
 934         inet_putpeer(peer);
 935 }
 936
 937 static int ip_error(struct sk_buff *skb)
 938 {
 939         struct rtable *rt = skb_rtable(skb);
 940         struct net_device *dev = skb->dev;
 941         struct in_device *in_dev;
 942         struct inet_peer *peer;
 943         unsigned long now;
 944         struct net *net;
 945         bool send;
 946         int code;
 947
 948         if (netif_is_l3_master(skb->dev)) {
 949                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
 950                 if (!dev)
 951                         goto out;
 952         }
 953
 954         in_dev = __in_dev_get_rcu(dev);
 955
 956         /* IP on this device is disabled. */
 957         if (!in_dev)
 958                 goto out;
 959
 960         net = dev_net(rt->dst.dev);
 961         if (!IN_DEV_FORWARD(in_dev)) {
 962                 switch (rt->dst.error) {
 963                 case EHOSTUNREACH:
 964                         __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
 965                         break;
 966
 967                 case ENETUNREACH:
 968                         __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 969                         break;
 970                 }
 971                 goto out;
 972         }
 973
 974         switch (rt->dst.error) {
 975         case EINVAL:
 976         default:
 977                 goto out;
 978         case EHOSTUNREACH:
 979                 code = ICMP_HOST_UNREACH;
 980                 break;
 981         case ENETUNREACH:
 982                 code = ICMP_NET_UNREACH;
 983                 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 984                 break;
 985         case EACCES:
 986                 code = ICMP_PKT_FILTERED;
 987                 break;
 988         }
 989
 990         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
 991                                l3mdev_master_ifindex(skb->dev), 1);
 992
 993         send = true;
 994         if (peer) {
 995                 now = jiffies;
 996                 peer->rate_tokens += now - peer->rate_last;
 997                 if (peer->rate_tokens > ip_rt_error_burst)
 998                         peer->rate_tokens = ip_rt_error_burst;
 999                 peer->rate_last = now;
1000                 if (peer->rate_tokens >= ip_rt_error_cost)
1001                         peer->rate_tokens -= ip_rt_error_cost;
1002                 else
1003                         send = false;
1004                 inet_putpeer(peer);
1005         }
1006         if (send)
1007                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1008
1009 out:    kfree_skb(skb);
1010         return 0;
1011 }
1012
1013 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1014 {
1015         struct dst_entry *dst = &rt->dst;
1016         struct fib_result res;
1017         bool lock = false;
1018
1019         if (ip_mtu_locked(dst))
1020                 return;
1021
1022         if (ipv4_mtu(dst) < mtu)
1023                 return;
1024
1025         if (mtu < ip_rt_min_pmtu) {
1026                 lock = true;
1027                 mtu = ip_rt_min_pmtu;
1028         }
1029
1030         if (rt->rt_pmtu == mtu &&
1031             time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1032                 return;
1033
1034         rcu_read_lock();
1035         if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1036                 struct fib_nh *nh = &FIB_RES_NH(res);
1037
1038                 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1039                                       jiffies + ip_rt_mtu_expires);
1040         }
1041         rcu_read_unlock();
1042 }
1043
1044 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1045                               struct sk_buff *skb, u32 mtu)
1046 {
1047         struct rtable *rt = (struct rtable *) dst;
1048         struct flowi4 fl4;
1049
1050         ip_rt_build_flow_key(&fl4, sk, skb);
1051         __ip_rt_update_pmtu(rt, &fl4, mtu);
1052 }
1053
1054 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1055                       int oif, u32 mark, u8 protocol, int flow_flags)
1056 {
1057         const struct iphdr *iph = (const struct iphdr *) skb->data;
1058         struct flowi4 fl4;
1059         struct rtable *rt;
1060
1061         if (!mark)
1062                 mark = IP4_REPLY_MARK(net, skb->mark);
1063
1064         __build_flow_key(net, &fl4, NULL, iph, oif,
1065                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1066         rt = __ip_route_output_key(net, &fl4);
1067         if (!IS_ERR(rt)) {
1068                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1069                 ip_rt_put(rt);
1070         }
1071 }
1072 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1073
1074 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1075 {
1076         const struct iphdr *iph = (const struct iphdr *) skb->data;
1077         struct flowi4 fl4;
1078         struct rtable *rt;
1079
1080         __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1081
1082         if (!fl4.flowi4_mark)
1083                 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1084
1085         rt = __ip_route_output_key(sock_net(sk), &fl4);
1086         if (!IS_ERR(rt)) {
1087                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1088                 ip_rt_put(rt);
1089         }
1090 }
1091
1092 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1093 {
1094         const struct iphdr *iph = (const struct iphdr *) skb->data;
1095         struct flowi4 fl4;
1096         struct rtable *rt;
1097         struct dst_entry *odst = NULL;
1098         bool new = false;
1099         struct net *net = sock_net(sk);
1100
1101         bh_lock_sock(sk);
1102
1103         if (!ip_sk_accept_pmtu(sk))
1104                 goto out;
1105
1106         odst = sk_dst_get(sk);
1107
1108         if (sock_owned_by_user(sk) || !odst) {
1109                 __ipv4_sk_update_pmtu(skb, sk, mtu);
1110                 goto out;
1111         }
1112
1113         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1114
1115         rt = (struct rtable *)odst;
1116         if (odst->obsolete && !odst->ops->check(odst, 0)) {
1117                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1118                 if (IS_ERR(rt))
1119                         goto out;
1120
1121                 new = true;
1122         }
1123
1124         __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1125
1126         if (!dst_check(&rt->dst, 0)) {
1127                 if (new)
1128                         dst_release(&rt->dst);
1129
1130                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1131                 if (IS_ERR(rt))
1132                         goto out;
1133
1134                 new = true;
1135         }
1136
1137         if (new)
1138                 sk_dst_set(sk, &rt->dst);
1139
1140 out:
1141         bh_unlock_sock(sk);
1142         dst_release(odst);
1143 }
1144 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1145
1146 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1147                    int oif, u32 mark, u8 protocol, int flow_flags)
1148 {
1149         const struct iphdr *iph = (const struct iphdr *) skb->data;
1150         struct flowi4 fl4;
1151         struct rtable *rt;
1152
1153         __build_flow_key(net, &fl4, NULL, iph, oif,
1154                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1155         rt = __ip_route_output_key(net, &fl4);
1156         if (!IS_ERR(rt)) {
1157                 __ip_do_redirect(rt, skb, &fl4, false);
1158                 ip_rt_put(rt);
1159         }
1160 }
1161 EXPORT_SYMBOL_GPL(ipv4_redirect);
1162
1163 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1164 {
1165         const struct iphdr *iph = (const struct iphdr *) skb->data;
1166         struct flowi4 fl4;
1167         struct rtable *rt;
1168         struct net *net = sock_net(sk);
1169
1170         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1171         rt = __ip_route_output_key(net, &fl4);
1172         if (!IS_ERR(rt)) {
1173                 __ip_do_redirect(rt, skb, &fl4, false);
1174                 ip_rt_put(rt);
1175         }
1176 }
1177 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1178
1179 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1180 {
1181         struct rtable *rt = (struct rtable *) dst;
1182
1183         /* All IPV4 dsts are created with ->obsolete set to the value
1184          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1185          * into this function always.
1186          *
1187          * When a PMTU/redirect information update invalidates a route,
1188          * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1189          * DST_OBSOLETE_DEAD by dst_free().
1190          */
1191         if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1192                 return NULL;
1193         return dst;
1194 }
1195
1196 static void ipv4_link_failure(struct sk_buff *skb)
1197 {
1198         struct rtable *rt;
1199
1200         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1201
1202         rt = skb_rtable(skb);
1203         if (rt)
1204                 dst_set_expires(&rt->dst, 0);
1205 }
1206
1207 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1208 {
1209         pr_debug("%s: %pI4 -> %pI4, %s\n",
1210                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1211                  skb->dev ? skb->dev->name : "?");
1212         kfree_skb(skb);
1213         WARN_ON(1);
1214         return 0;
1215 }
1216
1217 /*
1218    We do not cache source address of outgoing interface,
1219    because it is used only by IP RR, TS and SRR options,
1220    so that it out of fast path.
1221
1222    BTW remember: "addr" is allowed to be not aligned
1223    in IP options!
1224  */
1225
1226 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1227 {
1228         __be32 src;
1229
1230         if (rt_is_output_route(rt))
1231                 src = ip_hdr(skb)->saddr;
1232         else {
1233                 struct fib_result res;
1234                 struct flowi4 fl4;
1235                 struct iphdr *iph;
1236
1237                 iph = ip_hdr(skb);
1238
1239                 memset(&fl4, 0, sizeof(fl4));
1240                 fl4.daddr = iph->daddr;
1241                 fl4.saddr = iph->saddr;
1242                 fl4.flowi4_tos = RT_TOS(iph->tos);
1243                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1244                 fl4.flowi4_iif = skb->dev->ifindex;
1245                 fl4.flowi4_mark = skb->mark;
1246
1247                 rcu_read_lock();
1248                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1249                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1250                 else
1251                         src = inet_select_addr(rt->dst.dev,
1252                                                rt_nexthop(rt, iph->daddr),
1253                                                RT_SCOPE_UNIVERSE);
1254                 rcu_read_unlock();
1255         }
1256         memcpy(addr, &src, 4);
1257 }
1258
1259 #ifdef CONFIG_IP_ROUTE_CLASSID
1260 static void set_class_tag(struct rtable *rt, u32 tag)
1261 {
1262         if (!(rt->dst.tclassid & 0xFFFF))
1263                 rt->dst.tclassid |= tag & 0xFFFF;
1264         if (!(rt->dst.tclassid & 0xFFFF0000))
1265                 rt->dst.tclassid |= tag & 0xFFFF0000;
1266 }
1267 #endif
1268
1269 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1270 {
1271         unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1272         unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1273                                     ip_rt_min_advmss);
1274
1275         return min(advmss, IPV4_MAX_PMTU - header_size);
1276 }
1277
1278 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1279 {
1280         const struct rtable *rt = (const struct rtable *) dst;
1281         unsigned int mtu = rt->rt_pmtu;
1282
1283         if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1284                 mtu = dst_metric_raw(dst, RTAX_MTU);
1285
1286         if (mtu)
1287                 return mtu;
1288
1289         mtu = READ_ONCE(dst->dev->mtu);
1290
1291         if (unlikely(ip_mtu_locked(dst))) {
1292                 if (rt->rt_uses_gateway && mtu > 576)
1293                         mtu = 576;
1294         }
1295
1296         mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1297
1298         return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1299 }
1300
1301 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1302 {
1303         struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1304         struct fib_nh_exception *fnhe;
1305         u32 hval;
1306
1307         if (!hash)
1308                 return NULL;
1309
1310         hval = fnhe_hashfun(daddr);
1311
1312         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1313              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1314                 if (fnhe->fnhe_daddr == daddr)
1315                         return fnhe;
1316         }
1317         return NULL;
1318 }
1319
1320 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1321                               __be32 daddr, const bool do_cache)
1322 {
1323         bool ret = false;
1324
1325         spin_lock_bh(&fnhe_lock);
1326
1327         if (daddr == fnhe->fnhe_daddr) {
1328                 struct rtable __rcu **porig;
1329                 struct rtable *orig;
1330                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1331
1332                 if (rt_is_input_route(rt))
1333                         porig = &fnhe->fnhe_rth_input;
1334                 else
1335                         porig = &fnhe->fnhe_rth_output;
1336                 orig = rcu_dereference(*porig);
1337
1338                 if (fnhe->fnhe_genid != genid) {
1339                         fnhe->fnhe_genid = genid;
1340                         fnhe->fnhe_gw = 0;
1341                         fnhe->fnhe_pmtu = 0;
1342                         fnhe->fnhe_expires = 0;
1343                         fnhe_flush_routes(fnhe);
1344                         orig = NULL;
1345                 }
1346                 fill_route_from_fnhe(rt, fnhe);
1347                 if (!rt->rt_gateway)
1348                         rt->rt_gateway = daddr;
1349
1350                 if (do_cache) {
1351                         dst_hold(&rt->dst);
1352                         rcu_assign_pointer(*porig, rt);
1353                         if (orig) {
1354                                 dst_dev_put(&orig->dst);
1355                                 dst_release(&orig->dst);
1356                         }
1357                         ret = true;
1358                 }
1359
1360                 fnhe->fnhe_stamp = jiffies;
1361         }
1362         spin_unlock_bh(&fnhe_lock);
1363
1364         return ret;
1365 }
1366
1367 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1368 {
1369         struct rtable *orig, *prev, **p;
1370         bool ret = true;
1371
1372         if (rt_is_input_route(rt)) {
1373                 p = (struct rtable **)&nh->nh_rth_input;
1374         } else {
1375                 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1376         }
1377         orig = *p;
1378
1379         /* hold dst before doing cmpxchg() to avoid race condition
1380          * on this dst
1381          */
1382         dst_hold(&rt->dst);
1383         prev = cmpxchg(p, orig, rt);
1384         if (prev == orig) {
1385                 if (orig) {
1386                         dst_dev_put(&orig->dst);
1387                         dst_release(&orig->dst);
1388                 }
1389         } else {
1390                 dst_release(&rt->dst);
1391                 ret = false;
1392         }
1393
1394         return ret;
1395 }
1396
1397 struct uncached_list {
1398         spinlock_t              lock;
1399         struct list_head        head;
1400 };
1401
1402 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1403
1404 void rt_add_uncached_list(struct rtable *rt)
1405 {
1406         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1407
1408         rt->rt_uncached_list = ul;
1409
1410         spin_lock_bh(&ul->lock);
1411         list_add_tail(&rt->rt_uncached, &ul->head);
1412         spin_unlock_bh(&ul->lock);
1413 }
1414
1415 void rt_del_uncached_list(struct rtable *rt)
1416 {
1417         if (!list_empty(&rt->rt_uncached)) {
1418                 struct uncached_list *ul = rt->rt_uncached_list;
1419
1420                 spin_lock_bh(&ul->lock);
1421                 list_del(&rt->rt_uncached);
1422                 spin_unlock_bh(&ul->lock);
1423         }
1424 }
1425
1426 static void ipv4_dst_destroy(struct dst_entry *dst)
1427 {
1428         struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1429         struct rtable *rt = (struct rtable *)dst;
1430
1431         if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1432                 kfree(p);
1433
1434         rt_del_uncached_list(rt);
1435 }
1436
1437 void rt_flush_dev(struct net_device *dev)
1438 {
1439         struct net *net = dev_net(dev);
1440         struct rtable *rt;
1441         int cpu;
1442
1443         for_each_possible_cpu(cpu) {
1444                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1445
1446                 spin_lock_bh(&ul->lock);
1447                 list_for_each_entry(rt, &ul->head, rt_uncached) {
1448                         if (rt->dst.dev != dev)
1449                                 continue;
1450                         rt->dst.dev = net->loopback_dev;
1451                         dev_hold(rt->dst.dev);
1452                         dev_put(dev);
1453                 }
1454                 spin_unlock_bh(&ul->lock);
1455         }
1456 }
1457
1458 static bool rt_cache_valid(const struct rtable *rt)
1459 {
1460         return  rt &&
1461                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1462                 !rt_is_expired(rt);
1463 }
1464
1465 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1466                            const struct fib_result *res,
1467                            struct fib_nh_exception *fnhe,
1468                            struct fib_info *fi, u16 type, u32 itag,
1469                            const bool do_cache)
1470 {
1471         bool cached = false;
1472
1473         if (fi) {
1474                 struct fib_nh *nh = &FIB_RES_NH(*res);
1475
1476                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1477                         rt->rt_gateway = nh->nh_gw;
1478                         rt->rt_uses_gateway = 1;
1479                 }
1480                 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1481                 if (fi->fib_metrics != &dst_default_metrics) {
1482                         rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1483                         refcount_inc(&fi->fib_metrics->refcnt);
1484                 }
1485 #ifdef CONFIG_IP_ROUTE_CLASSID
1486                 rt->dst.tclassid = nh->nh_tclassid;
1487 #endif
1488                 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1489                 if (unlikely(fnhe))
1490                         cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1491                 else if (do_cache)
1492                         cached = rt_cache_route(nh, rt);
1493                 if (unlikely(!cached)) {
1494                         /* Routes we intend to cache in nexthop exception or
1495                          * FIB nexthop have the DST_NOCACHE bit clear.
1496                          * However, if we are unsuccessful at storing this
1497                          * route into the cache we really need to set it.
1498                          */
1499                         if (!rt->rt_gateway)
1500                                 rt->rt_gateway = daddr;
1501                         rt_add_uncached_list(rt);
1502                 }
1503         } else
1504                 rt_add_uncached_list(rt);
1505
1506 #ifdef CONFIG_IP_ROUTE_CLASSID
1507 #ifdef CONFIG_IP_MULTIPLE_TABLES
1508         set_class_tag(rt, res->tclassid);
1509 #endif
1510         set_class_tag(rt, itag);
1511 #endif
1512 }
1513
1514 struct rtable *rt_dst_alloc(struct net_device *dev,
1515                             unsigned int flags, u16 type,
1516                             bool nopolicy, bool noxfrm, bool will_cache)
1517 {
1518         struct rtable *rt;
1519
1520         rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1521                        (will_cache ? 0 : DST_HOST) |
1522                        (nopolicy ? DST_NOPOLICY : 0) |
1523                        (noxfrm ? DST_NOXFRM : 0));
1524
1525         if (rt) {
1526                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1527                 rt->rt_flags = flags;
1528                 rt->rt_type = type;
1529                 rt->rt_is_input = 0;
1530                 rt->rt_iif = 0;
1531                 rt->rt_pmtu = 0;
1532                 rt->rt_mtu_locked = 0;
1533                 rt->rt_gateway = 0;
1534                 rt->rt_uses_gateway = 0;
1535                 INIT_LIST_HEAD(&rt->rt_uncached);
1536
1537                 rt->dst.output = ip_output;
1538                 if (flags & RTCF_LOCAL)
1539                         rt->dst.input = ip_local_deliver;
1540         }
1541
1542         return rt;
1543 }
1544 EXPORT_SYMBOL(rt_dst_alloc);
1545
1546 /* called in rcu_read_lock() section */
1547 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1548                           u8 tos, struct net_device *dev,
1549                           struct in_device *in_dev, u32 *itag)
1550 {
1551         int err;
1552
1553         /* Primary sanity checks. */
1554         if (!in_dev)
1555                 return -EINVAL;
1556
1557         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1558             skb->protocol != htons(ETH_P_IP))
1559                 return -EINVAL;
1560
1561         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1562                 return -EINVAL;
1563
1564         if (ipv4_is_zeronet(saddr)) {
1565                 if (!ipv4_is_local_multicast(daddr))
1566                         return -EINVAL;
1567         } else {
1568                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1569                                           in_dev, itag);
1570                 if (err < 0)
1571                         return err;
1572         }
1573         return 0;
1574 }
1575
1576 /* called in rcu_read_lock() section */
1577 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1578                              u8 tos, struct net_device *dev, int our)
1579 {
1580         struct in_device *in_dev = __in_dev_get_rcu(dev);
1581         unsigned int flags = RTCF_MULTICAST;
1582         struct rtable *rth;
1583         u32 itag = 0;
1584         int err;
1585
1586         err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1587         if (err)
1588                 return err;
1589
1590         if (our)
1591                 flags |= RTCF_LOCAL;
1592
1593         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1594                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1595         if (!rth)
1596                 return -ENOBUFS;
1597
1598 #ifdef CONFIG_IP_ROUTE_CLASSID
1599         rth->dst.tclassid = itag;
1600 #endif
1601         rth->dst.output = ip_rt_bug;
1602         rth->rt_is_input= 1;
1603
1604 #ifdef CONFIG_IP_MROUTE
1605         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1606                 rth->dst.input = ip_mr_input;
1607 #endif
1608         RT_CACHE_STAT_INC(in_slow_mc);
1609
1610         skb_dst_set(skb, &rth->dst);
1611         return 0;
1612 }
1613
1614
1615 static void ip_handle_martian_source(struct net_device *dev,
1616                                      struct in_device *in_dev,
1617                                      struct sk_buff *skb,
1618                                      __be32 daddr,
1619                                      __be32 saddr)
1620 {
1621         RT_CACHE_STAT_INC(in_martian_src);
1622 #ifdef CONFIG_IP_ROUTE_VERBOSE
1623         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1624                 /*
1625                  *      RFC1812 recommendation, if source is martian,
1626                  *      the only hint is MAC header.
1627                  */
1628                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1629                         &daddr, &saddr, dev->name);
1630                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1631                         print_hex_dump(KERN_WARNING, "ll header: ",
1632                                        DUMP_PREFIX_OFFSET, 16, 1,
1633                                        skb_mac_header(skb),
1634                                        dev->hard_header_len, true);
1635                 }
1636         }
1637 #endif
1638 }
1639
1640 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1641 {
1642         struct fnhe_hash_bucket *hash;
1643         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1644         u32 hval = fnhe_hashfun(daddr);
1645
1646         spin_lock_bh(&fnhe_lock);
1647
1648         hash = rcu_dereference_protected(nh->nh_exceptions,
1649                                          lockdep_is_held(&fnhe_lock));
1650         hash += hval;
1651
1652         fnhe_p = &hash->chain;
1653         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1654         while (fnhe) {
1655                 if (fnhe->fnhe_daddr == daddr) {
1656                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1657                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1658                         fnhe_flush_routes(fnhe);
1659                         kfree_rcu(fnhe, rcu);
1660                         break;
1661                 }
1662                 fnhe_p = &fnhe->fnhe_next;
1663                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1664                                                  lockdep_is_held(&fnhe_lock));
1665         }
1666
1667         spin_unlock_bh(&fnhe_lock);
1668 }
1669
1670 /* called in rcu_read_lock() section */
1671 static int __mkroute_input(struct sk_buff *skb,
1672                            const struct fib_result *res,
1673                            struct in_device *in_dev,
1674                            __be32 daddr, __be32 saddr, u32 tos)
1675 {
1676         struct fib_nh_exception *fnhe;
1677         struct rtable *rth;
1678         int err;
1679         struct in_device *out_dev;
1680         bool do_cache;
1681         u32 itag = 0;
1682
1683         /* get a working reference to the output device */
1684         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1685         if (!out_dev) {
1686                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1687                 return -EINVAL;
1688         }
1689
1690         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1691                                   in_dev->dev, in_dev, &itag);
1692         if (err < 0) {
1693                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1694                                          saddr);
1695
1696                 goto cleanup;
1697         }
1698
1699         do_cache = res->fi && !itag;
1700         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1701             skb->protocol == htons(ETH_P_IP) &&
1702             (IN_DEV_SHARED_MEDIA(out_dev) ||
1703              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1704                 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1705
1706         if (skb->protocol != htons(ETH_P_IP)) {
1707                 /* Not IP (i.e. ARP). Do not create route, if it is
1708                  * invalid for proxy arp. DNAT routes are always valid.
1709                  *
1710                  * Proxy arp feature have been extended to allow, ARP
1711                  * replies back to the same interface, to support
1712                  * Private VLAN switch technologies. See arp.c.
1713                  */
1714                 if (out_dev == in_dev &&
1715                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1716                         err = -EINVAL;
1717                         goto cleanup;
1718                 }
1719         }
1720
1721         fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1722         if (do_cache) {
1723                 if (fnhe) {
1724                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1725                         if (rth && rth->dst.expires &&
1726                             time_after(jiffies, rth->dst.expires)) {
1727                                 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1728                                 fnhe = NULL;
1729                         } else {
1730                                 goto rt_cache;
1731                         }
1732                 }
1733
1734                 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1735
1736 rt_cache:
1737                 if (rt_cache_valid(rth)) {
1738                         skb_dst_set_noref(skb, &rth->dst);
1739                         goto out;
1740                 }
1741         }
1742
1743         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1744                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1745                            IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1746         if (!rth) {
1747                 err = -ENOBUFS;
1748                 goto cleanup;
1749         }
1750
1751         rth->rt_is_input = 1;
1752         RT_CACHE_STAT_INC(in_slow_tot);
1753
1754         rth->dst.input = ip_forward;
1755
1756         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1757                        do_cache);
1758         lwtunnel_set_redirect(&rth->dst);
1759         skb_dst_set(skb, &rth->dst);
1760 out:
1761         err = 0;
1762  cleanup:
1763         return err;
1764 }
1765
1766 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1767 /* To make ICMP packets follow the right flow, the multipath hash is
1768  * calculated from the inner IP addresses.
1769  */
1770 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1771                                  struct flow_keys *hash_keys)
1772 {
1773         const struct iphdr *outer_iph = ip_hdr(skb);
1774         const struct iphdr *key_iph = outer_iph;
1775         const struct iphdr *inner_iph;
1776         const struct icmphdr *icmph;
1777         struct iphdr _inner_iph;
1778         struct icmphdr _icmph;
1779
1780         if (likely(outer_iph->protocol != IPPROTO_ICMP))
1781                 goto out;
1782
1783         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1784                 goto out;
1785
1786         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1787                                    &_icmph);
1788         if (!icmph)
1789                 goto out;
1790
1791         if (icmph->type != ICMP_DEST_UNREACH &&
1792             icmph->type != ICMP_REDIRECT &&
1793             icmph->type != ICMP_TIME_EXCEEDED &&
1794             icmph->type != ICMP_PARAMETERPROB)
1795                 goto out;
1796
1797         inner_iph = skb_header_pointer(skb,
1798                                        outer_iph->ihl * 4 + sizeof(_icmph),
1799                                        sizeof(_inner_iph), &_inner_iph);
1800         if (!inner_iph)
1801                 goto out;
1802
1803         key_iph = inner_iph;
1804 out:
1805         hash_keys->addrs.v4addrs.src = key_iph->saddr;
1806         hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1807 }
1808
1809 /* if skb is set it will be used and fl4 can be NULL */
1810 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1811                        const struct sk_buff *skb, struct flow_keys *flkeys)
1812 {
1813         struct flow_keys hash_keys;
1814         u32 mhash;
1815
1816         switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1817         case 0:
1818                 memset(&hash_keys, 0, sizeof(hash_keys));
1819                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1820                 if (skb) {
1821                         ip_multipath_l3_keys(skb, &hash_keys);
1822                 } else {
1823                         hash_keys.addrs.v4addrs.src = fl4->saddr;
1824                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
1825                 }
1826                 break;
1827         case 1:
1828                 /* skb is currently provided only when forwarding */
1829                 if (skb) {
1830                         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1831                         struct flow_keys keys;
1832
1833                         /* short-circuit if we already have L4 hash present */
1834                         if (skb->l4_hash)
1835                                 return skb_get_hash_raw(skb) >> 1;
1836
1837                         memset(&hash_keys, 0, sizeof(hash_keys));
1838
1839                         if (!flkeys) {
1840                                 skb_flow_dissect_flow_keys(skb, &keys, flag);
1841                                 flkeys = &keys;
1842                         }
1843
1844                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1845                         hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1846                         hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1847                         hash_keys.ports.src = flkeys->ports.src;
1848                         hash_keys.ports.dst = flkeys->ports.dst;
1849                         hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1850                 } else {
1851                         memset(&hash_keys, 0, sizeof(hash_keys));
1852                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1853                         hash_keys.addrs.v4addrs.src = fl4->saddr;
1854                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
1855                         hash_keys.ports.src = fl4->fl4_sport;
1856                         hash_keys.ports.dst = fl4->fl4_dport;
1857                         hash_keys.basic.ip_proto = fl4->flowi4_proto;
1858                 }
1859                 break;
1860         }
1861         mhash = flow_hash_from_keys(&hash_keys);
1862
1863         return mhash >> 1;
1864 }
1865 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1866
1867 static int ip_mkroute_input(struct sk_buff *skb,
1868                             struct fib_result *res,
1869                             struct in_device *in_dev,
1870                             __be32 daddr, __be32 saddr, u32 tos,
1871                             struct flow_keys *hkeys)
1872 {
1873 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1874         if (res->fi && res->fi->fib_nhs > 1) {
1875                 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
1876
1877                 fib_select_multipath(res, h);
1878         }
1879 #endif
1880
1881         /* create a routing cache entry */
1882         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1883 }
1884
1885 /*
1886  *      NOTE. We drop all the packets that has local source
1887  *      addresses, because every properly looped back packet
1888  *      must have correct destination already attached by output routine.
1889  *
1890  *      Such approach solves two big problems:
1891  *      1. Not simplex devices are handled properly.
1892  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1893  *      called with rcu_read_lock()
1894  */
1895
1896 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1897                                u8 tos, struct net_device *dev,
1898                                struct fib_result *res)
1899 {
1900         struct in_device *in_dev = __in_dev_get_rcu(dev);
1901         struct flow_keys *flkeys = NULL, _flkeys;
1902         struct net    *net = dev_net(dev);
1903         struct ip_tunnel_info *tun_info;
1904         int             err = -EINVAL;
1905         unsigned int    flags = 0;
1906         u32             itag = 0;
1907         struct rtable   *rth;
1908         struct flowi4   fl4;
1909         bool do_cache;
1910
1911         /* IP on this device is disabled. */
1912
1913         if (!in_dev)
1914                 goto out;
1915
1916         /* Check for the most weird martians, which can be not detected
1917            by fib_lookup.
1918          */
1919
1920         tun_info = skb_tunnel_info(skb);
1921         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1922                 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1923         else
1924                 fl4.flowi4_tun_key.tun_id = 0;
1925         skb_dst_drop(skb);
1926
1927         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1928                 goto martian_source;
1929
1930         res->fi = NULL;
1931         res->table = NULL;
1932         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1933                 goto brd_input;
1934
1935         /* Accept zero addresses only to limited broadcast;
1936          * I even do not know to fix it or not. Waiting for complains :-)
1937          */
1938         if (ipv4_is_zeronet(saddr))
1939                 goto martian_source;
1940
1941         if (ipv4_is_zeronet(daddr))
1942                 goto martian_destination;
1943
1944         /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1945          * and call it once if daddr or/and saddr are loopback addresses
1946          */
1947         if (ipv4_is_loopback(daddr)) {
1948                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1949                         goto martian_destination;
1950         } else if (ipv4_is_loopback(saddr)) {
1951                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1952                         goto martian_source;
1953         }
1954
1955         /*
1956          *      Now we are ready to route packet.
1957          */
1958         fl4.flowi4_oif = 0;
1959         fl4.flowi4_iif = dev->ifindex;
1960         fl4.flowi4_mark = skb->mark;
1961         fl4.flowi4_tos = tos;
1962         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1963         fl4.flowi4_flags = 0;
1964         fl4.daddr = daddr;
1965         fl4.saddr = saddr;
1966         fl4.flowi4_uid = sock_net_uid(net, NULL);
1967
1968         if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys))
1969                 flkeys = &_flkeys;
1970
1971         err = fib_lookup(net, &fl4, res, 0);
1972         if (err != 0) {
1973                 if (!IN_DEV_FORWARD(in_dev))
1974                         err = -EHOSTUNREACH;
1975                 goto no_route;
1976         }
1977
1978         if (res->type == RTN_BROADCAST)
1979                 goto brd_input;
1980
1981         if (res->type == RTN_LOCAL) {
1982                 err = fib_validate_source(skb, saddr, daddr, tos,
1983                                           0, dev, in_dev, &itag);
1984                 if (err < 0)
1985                         goto martian_source;
1986                 goto local_input;
1987         }
1988
1989         if (!IN_DEV_FORWARD(in_dev)) {
1990                 err = -EHOSTUNREACH;
1991                 goto no_route;
1992         }
1993         if (res->type != RTN_UNICAST)
1994                 goto martian_destination;
1995
1996         err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
1997 out:    return err;
1998
1999 brd_input:
2000         if (skb->protocol != htons(ETH_P_IP))
2001                 goto e_inval;
2002
2003         if (!ipv4_is_zeronet(saddr)) {
2004                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2005                                           in_dev, &itag);
2006                 if (err < 0)
2007                         goto martian_source;
2008         }
2009         flags |= RTCF_BROADCAST;
2010         res->type = RTN_BROADCAST;
2011         RT_CACHE_STAT_INC(in_brd);
2012
2013 local_input:
2014         do_cache = false;
2015         if (res->fi) {
2016                 if (!itag) {
2017                         rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2018                         if (rt_cache_valid(rth)) {
2019                                 skb_dst_set_noref(skb, &rth->dst);
2020                                 err = 0;
2021                                 goto out;
2022                         }
2023                         do_cache = true;
2024                 }
2025         }
2026
2027         rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2028                            flags | RTCF_LOCAL, res->type,
2029                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2030         if (!rth)
2031                 goto e_nobufs;
2032
2033         rth->dst.output= ip_rt_bug;
2034 #ifdef CONFIG_IP_ROUTE_CLASSID
2035         rth->dst.tclassid = itag;
2036 #endif
2037         rth->rt_is_input = 1;
2038
2039         RT_CACHE_STAT_INC(in_slow_tot);
2040         if (res->type == RTN_UNREACHABLE) {
2041                 rth->dst.input= ip_error;
2042                 rth->dst.error= -err;
2043                 rth->rt_flags   &= ~RTCF_LOCAL;
2044         }
2045
2046         if (do_cache) {
2047                 struct fib_nh *nh = &FIB_RES_NH(*res);
2048
2049                 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2050                 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2051                         WARN_ON(rth->dst.input == lwtunnel_input);
2052                         rth->dst.lwtstate->orig_input = rth->dst.input;
2053                         rth->dst.input = lwtunnel_input;
2054                 }
2055
2056                 if (unlikely(!rt_cache_route(nh, rth)))
2057                         rt_add_uncached_list(rth);
2058         }
2059         skb_dst_set(skb, &rth->dst);
2060         err = 0;
2061         goto out;
2062
2063 no_route:
2064         RT_CACHE_STAT_INC(in_no_route);
2065         res->type = RTN_UNREACHABLE;
2066         res->fi = NULL;
2067         res->table = NULL;
2068         goto local_input;
2069
2070         /*
2071          *      Do not cache martian addresses: they should be logged (RFC1812)
2072          */
2073 martian_destination:
2074         RT_CACHE_STAT_INC(in_martian_dst);
2075 #ifdef CONFIG_IP_ROUTE_VERBOSE
2076         if (IN_DEV_LOG_MARTIANS(in_dev))
2077                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2078                                      &daddr, &saddr, dev->name);
2079 #endif
2080
2081 e_inval:
2082         err = -EINVAL;
2083         goto out;
2084
2085 e_nobufs:
2086         err = -ENOBUFS;
2087         goto out;
2088
2089 martian_source:
2090         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2091         goto out;
2092 }
2093
2094 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2095                          u8 tos, struct net_device *dev)
2096 {
2097         struct fib_result res;
2098         int err;
2099
2100         tos &= IPTOS_RT_MASK;
2101         rcu_read_lock();
2102         err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2103         rcu_read_unlock();
2104
2105         return err;
2106 }
2107 EXPORT_SYMBOL(ip_route_input_noref);
2108
2109 /* called with rcu_read_lock held */
2110 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2111                        u8 tos, struct net_device *dev, struct fib_result *res)
2112 {
2113         /* Multicast recognition logic is moved from route cache to here.
2114            The problem was that too many Ethernet cards have broken/missing
2115            hardware multicast filters :-( As result the host on multicasting
2116            network acquires a lot of useless route cache entries, sort of
2117            SDR messages from all the world. Now we try to get rid of them.
2118            Really, provided software IP multicast filter is organized
2119            reasonably (at least, hashed), it does not result in a slowdown
2120            comparing with route cache reject entries.
2121            Note, that multicast routers are not affected, because
2122            route cache entry is created eventually.
2123          */
2124         if (ipv4_is_multicast(daddr)) {
2125                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2126                 int our = 0;
2127                 int err = -EINVAL;
2128
2129                 if (in_dev)
2130                         our = ip_check_mc_rcu(in_dev, daddr, saddr,
2131                                               ip_hdr(skb)->protocol);
2132
2133                 /* check l3 master if no match yet */
2134                 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2135                         struct in_device *l3_in_dev;
2136
2137                         l3_in_dev = __in_dev_get_rcu(skb->dev);
2138                         if (l3_in_dev)
2139                                 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2140                                                       ip_hdr(skb)->protocol);
2141                 }
2142
2143                 if (our
2144 #ifdef CONFIG_IP_MROUTE
2145                         ||
2146                     (!ipv4_is_local_multicast(daddr) &&
2147                      IN_DEV_MFORWARD(in_dev))
2148 #endif
2149                    ) {
2150                         err = ip_route_input_mc(skb, daddr, saddr,
2151                                                 tos, dev, our);
2152                 }
2153                 return err;
2154         }
2155
2156         return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2157 }
2158
2159 /* called with rcu_read_lock() */
2160 static struct rtable *__mkroute_output(const struct fib_result *res,
2161                                        const struct flowi4 *fl4, int orig_oif,
2162                                        struct net_device *dev_out,
2163                                        unsigned int flags)
2164 {
2165         struct fib_info *fi = res->fi;
2166         struct fib_nh_exception *fnhe;
2167         struct in_device *in_dev;
2168         u16 type = res->type;
2169         struct rtable *rth;
2170         bool do_cache;
2171
2172         in_dev = __in_dev_get_rcu(dev_out);
2173         if (!in_dev)
2174                 return ERR_PTR(-EINVAL);
2175
2176         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2177                 if (ipv4_is_loopback(fl4->saddr) &&
2178                     !(dev_out->flags & IFF_LOOPBACK) &&
2179                     !netif_is_l3_master(dev_out))
2180                         return ERR_PTR(-EINVAL);
2181
2182         if (ipv4_is_lbcast(fl4->daddr))
2183                 type = RTN_BROADCAST;
2184         else if (ipv4_is_multicast(fl4->daddr))
2185                 type = RTN_MULTICAST;
2186         else if (ipv4_is_zeronet(fl4->daddr))
2187                 return ERR_PTR(-EINVAL);
2188
2189         if (dev_out->flags & IFF_LOOPBACK)
2190                 flags |= RTCF_LOCAL;
2191
2192         do_cache = true;
2193         if (type == RTN_BROADCAST) {
2194                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2195                 fi = NULL;
2196         } else if (type == RTN_MULTICAST) {
2197                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2198                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2199                                      fl4->flowi4_proto))
2200                         flags &= ~RTCF_LOCAL;
2201                 else
2202                         do_cache = false;
2203                 /* If multicast route do not exist use
2204                  * default one, but do not gateway in this case.
2205                  * Yes, it is hack.
2206                  */
2207                 if (fi && res->prefixlen < 4)
2208                         fi = NULL;
2209         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2210                    (orig_oif != dev_out->ifindex)) {
2211                 /* For local routes that require a particular output interface
2212                  * we do not want to cache the result.  Caching the result
2213                  * causes incorrect behaviour when there are multiple source
2214                  * addresses on the interface, the end result being that if the
2215                  * intended recipient is waiting on that interface for the
2216                  * packet he won't receive it because it will be delivered on
2217                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2218                  * be set to the loopback interface as well.
2219                  */
2220                 fi = NULL;
2221         }
2222
2223         fnhe = NULL;
2224         do_cache &= fi != NULL;
2225         if (do_cache) {
2226                 struct rtable __rcu **prth;
2227                 struct fib_nh *nh = &FIB_RES_NH(*res);
2228
2229                 fnhe = find_exception(nh, fl4->daddr);
2230                 if (fnhe) {
2231                         prth = &fnhe->fnhe_rth_output;
2232                         rth = rcu_dereference(*prth);
2233                         if (rth && rth->dst.expires &&
2234                             time_after(jiffies, rth->dst.expires)) {
2235                                 ip_del_fnhe(nh, fl4->daddr);
2236                                 fnhe = NULL;
2237                         } else {
2238                                 goto rt_cache;
2239                         }
2240                 }
2241
2242                 if (unlikely(fl4->flowi4_flags &
2243                              FLOWI_FLAG_KNOWN_NH &&
2244                              !(nh->nh_gw &&
2245                                nh->nh_scope == RT_SCOPE_LINK))) {
2246                         do_cache = false;
2247                         goto add;
2248                 }
2249                 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2250                 rth = rcu_dereference(*prth);
2251
2252 rt_cache:
2253                 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2254                         return rth;
2255         }
2256
2257 add:
2258         rth = rt_dst_alloc(dev_out, flags, type,
2259                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2260                            IN_DEV_CONF_GET(in_dev, NOXFRM),
2261                            do_cache);
2262         if (!rth)
2263                 return ERR_PTR(-ENOBUFS);
2264
2265         rth->rt_iif = orig_oif;
2266
2267         RT_CACHE_STAT_INC(out_slow_tot);
2268
2269         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2270                 if (flags & RTCF_LOCAL &&
2271                     !(dev_out->flags & IFF_LOOPBACK)) {
2272                         rth->dst.output = ip_mc_output;
2273                         RT_CACHE_STAT_INC(out_slow_mc);
2274                 }
2275 #ifdef CONFIG_IP_MROUTE
2276                 if (type == RTN_MULTICAST) {
2277                         if (IN_DEV_MFORWARD(in_dev) &&
2278                             !ipv4_is_local_multicast(fl4->daddr)) {
2279                                 rth->dst.input = ip_mr_input;
2280                                 rth->dst.output = ip_mc_output;
2281                         }
2282                 }
2283 #endif
2284         }
2285
2286         rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2287         lwtunnel_set_redirect(&rth->dst);
2288
2289         return rth;
2290 }
2291
2292 /*
2293  * Major route resolver routine.
2294  */
2295
2296 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2297                                         const struct sk_buff *skb)
2298 {
2299         __u8 tos = RT_FL_TOS(fl4);
2300         struct fib_result res = {
2301                 .type           = RTN_UNSPEC,
2302                 .fi             = NULL,
2303                 .table          = NULL,
2304                 .tclassid       = 0,
2305         };
2306         struct rtable *rth;
2307
2308         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2309         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2310         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2311                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2312
2313         rcu_read_lock();
2314         rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2315         rcu_read_unlock();
2316
2317         return rth;
2318 }
2319 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2320
2321 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2322                                             struct fib_result *res,
2323                                             const struct sk_buff *skb)
2324 {
2325         struct net_device *dev_out = NULL;
2326         int orig_oif = fl4->flowi4_oif;
2327         unsigned int flags = 0;
2328         struct rtable *rth;
2329         int err = -ENETUNREACH;
2330
2331         if (fl4->saddr) {
2332                 rth = ERR_PTR(-EINVAL);
2333                 if (ipv4_is_multicast(fl4->saddr) ||
2334                     ipv4_is_lbcast(fl4->saddr) ||
2335                     ipv4_is_zeronet(fl4->saddr))
2336                         goto out;
2337
2338                 /* I removed check for oif == dev_out->oif here.
2339                    It was wrong for two reasons:
2340                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2341                       is assigned to multiple interfaces.
2342                    2. Moreover, we are allowed to send packets with saddr
2343                       of another iface. --ANK
2344                  */
2345
2346                 if (fl4->flowi4_oif == 0 &&
2347                     (ipv4_is_multicast(fl4->daddr) ||
2348                      ipv4_is_lbcast(fl4->daddr))) {
2349                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2350                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2351                         if (!dev_out)
2352                                 goto out;
2353
2354                         /* Special hack: user can direct multicasts
2355                            and limited broadcast via necessary interface
2356                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2357                            This hack is not just for fun, it allows
2358                            vic,vat and friends to work.
2359                            They bind socket to loopback, set ttl to zero
2360                            and expect that it will work.
2361                            From the viewpoint of routing cache they are broken,
2362                            because we are not allowed to build multicast path
2363                            with loopback source addr (look, routing cache
2364                            cannot know, that ttl is zero, so that packet
2365                            will not leave this host and route is valid).
2366                            Luckily, this hack is good workaround.
2367                          */
2368
2369                         fl4->flowi4_oif = dev_out->ifindex;
2370                         goto make_route;
2371                 }
2372
2373                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2374                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2375                         if (!__ip_dev_find(net, fl4->saddr, false))
2376                                 goto out;
2377                 }
2378         }
2379
2380
2381         if (fl4->flowi4_oif) {
2382                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2383                 rth = ERR_PTR(-ENODEV);
2384                 if (!dev_out)
2385                         goto out;
2386
2387                 /* RACE: Check return value of inet_select_addr instead. */
2388                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2389                         rth = ERR_PTR(-ENETUNREACH);
2390                         goto out;
2391                 }
2392                 if (ipv4_is_local_multicast(fl4->daddr) ||
2393                     ipv4_is_lbcast(fl4->daddr) ||
2394                     fl4->flowi4_proto == IPPROTO_IGMP) {
2395                         if (!fl4->saddr)
2396                                 fl4->saddr = inet_select_addr(dev_out, 0,
2397                                                               RT_SCOPE_LINK);
2398                         goto make_route;
2399                 }
2400                 if (!fl4->saddr) {
2401                         if (ipv4_is_multicast(fl4->daddr))
2402                                 fl4->saddr = inet_select_addr(dev_out, 0,
2403                                                               fl4->flowi4_scope);
2404                         else if (!fl4->daddr)
2405                                 fl4->saddr = inet_select_addr(dev_out, 0,
2406                                                               RT_SCOPE_HOST);
2407                 }
2408         }
2409
2410         if (!fl4->daddr) {
2411                 fl4->daddr = fl4->saddr;
2412                 if (!fl4->daddr)
2413                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2414                 dev_out = net->loopback_dev;
2415                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2416                 res->type = RTN_LOCAL;
2417                 flags |= RTCF_LOCAL;
2418                 goto make_route;
2419         }
2420
2421         err = fib_lookup(net, fl4, res, 0);
2422         if (err) {
2423                 res->fi = NULL;
2424                 res->table = NULL;
2425                 if (fl4->flowi4_oif &&
2426                     (ipv4_is_multicast(fl4->daddr) ||
2427                     !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2428                         /* Apparently, routing tables are wrong. Assume,
2429                            that the destination is on link.
2430
2431                            WHY? DW.
2432                            Because we are allowed to send to iface
2433                            even if it has NO routes and NO assigned
2434                            addresses. When oif is specified, routing
2435                            tables are looked up with only one purpose:
2436                            to catch if destination is gatewayed, rather than
2437                            direct. Moreover, if MSG_DONTROUTE is set,
2438                            we send packet, ignoring both routing tables
2439                            and ifaddr state. --ANK
2440
2441
2442                            We could make it even if oif is unknown,
2443                            likely IPv6, but we do not.
2444                          */
2445
2446                         if (fl4->saddr == 0)
2447                                 fl4->saddr = inet_select_addr(dev_out, 0,
2448                                                               RT_SCOPE_LINK);
2449                         res->type = RTN_UNICAST;
2450                         goto make_route;
2451                 }
2452                 rth = ERR_PTR(err);
2453                 goto out;
2454         }
2455
2456         if (res->type == RTN_LOCAL) {
2457                 if (!fl4->saddr) {
2458                         if (res->fi->fib_prefsrc)
2459                                 fl4->saddr = res->fi->fib_prefsrc;
2460                         else
2461                                 fl4->saddr = fl4->daddr;
2462                 }
2463
2464                 /* L3 master device is the loopback for that domain */
2465                 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2466                         net->loopback_dev;
2467
2468                 /* make sure orig_oif points to fib result device even
2469                  * though packet rx/tx happens over loopback or l3mdev
2470                  */
2471                 orig_oif = FIB_RES_OIF(*res);
2472
2473                 fl4->flowi4_oif = dev_out->ifindex;
2474                 flags |= RTCF_LOCAL;
2475                 goto make_route;
2476         }
2477
2478         fib_select_path(net, res, fl4, skb);
2479
2480         dev_out = FIB_RES_DEV(*res);
2481         fl4->flowi4_oif = dev_out->ifindex;
2482
2483
2484 make_route:
2485         rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2486
2487 out:
2488         return rth;
2489 }
2490
2491 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2492 {
2493         return NULL;
2494 }
2495
2496 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2497 {
2498         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2499
2500         return mtu ? : dst->dev->mtu;
2501 }
2502
2503 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2504                                           struct sk_buff *skb, u32 mtu)
2505 {
2506 }
2507
2508 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2509                                        struct sk_buff *skb)
2510 {
2511 }
2512
2513 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2514                                           unsigned long old)
2515 {
2516         return NULL;
2517 }
2518
2519 static struct dst_ops ipv4_dst_blackhole_ops = {
2520         .family                 =       AF_INET,
2521         .check                  =       ipv4_blackhole_dst_check,
2522         .mtu                    =       ipv4_blackhole_mtu,
2523         .default_advmss         =       ipv4_default_advmss,
2524         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2525         .redirect               =       ipv4_rt_blackhole_redirect,
2526         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2527         .neigh_lookup           =       ipv4_neigh_lookup,
2528 };
2529
2530 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2531 {
2532         struct rtable *ort = (struct rtable *) dst_orig;
2533         struct rtable *rt;
2534
2535         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2536         if (rt) {
2537                 struct dst_entry *new = &rt->dst;
2538
2539                 new->__use = 1;
2540                 new->input = dst_discard;
2541                 new->output = dst_discard_out;
2542
2543                 new->dev = net->loopback_dev;
2544                 if (new->dev)
2545                         dev_hold(new->dev);
2546
2547                 rt->rt_is_input = ort->rt_is_input;
2548                 rt->rt_iif = ort->rt_iif;
2549                 rt->rt_pmtu = ort->rt_pmtu;
2550                 rt->rt_mtu_locked = ort->rt_mtu_locked;
2551
2552                 rt->rt_genid = rt_genid_ipv4(net);
2553                 rt->rt_flags = ort->rt_flags;
2554                 rt->rt_type = ort->rt_type;
2555                 rt->rt_gateway = ort->rt_gateway;
2556                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2557
2558                 INIT_LIST_HEAD(&rt->rt_uncached);
2559         }
2560
2561         dst_release(dst_orig);
2562
2563         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2564 }
2565
2566 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2567                                     const struct sock *sk)
2568 {
2569         struct rtable *rt = __ip_route_output_key(net, flp4);
2570
2571         if (IS_ERR(rt))
2572                 return rt;
2573
2574         if (flp4->flowi4_proto)
2575                 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2576                                                         flowi4_to_flowi(flp4),
2577                                                         sk, 0);
2578
2579         return rt;
2580 }
2581 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2582
2583 /* called with rcu_read_lock held */
2584 static int rt_fill_info(struct net *net,  __be32 dst, __be32 src, u32 table_id,
2585                         struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2586                         u32 seq)
2587 {
2588         struct rtable *rt = skb_rtable(skb);
2589         struct rtmsg *r;
2590         struct nlmsghdr *nlh;
2591         unsigned long expires = 0;
2592         u32 error;
2593         u32 metrics[RTAX_MAX];
2594
2595         nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2596         if (!nlh)
2597                 return -EMSGSIZE;
2598
2599         r = nlmsg_data(nlh);
2600         r->rtm_family    = AF_INET;
2601         r->rtm_dst_len  = 32;
2602         r->rtm_src_len  = 0;
2603         r->rtm_tos      = fl4->flowi4_tos;
2604         r->rtm_table    = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2605         if (nla_put_u32(skb, RTA_TABLE, table_id))
2606                 goto nla_put_failure;
2607         r->rtm_type     = rt->rt_type;
2608         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2609         r->rtm_protocol = RTPROT_UNSPEC;
2610         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2611         if (rt->rt_flags & RTCF_NOTIFY)
2612                 r->rtm_flags |= RTM_F_NOTIFY;
2613         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2614                 r->rtm_flags |= RTCF_DOREDIRECT;
2615
2616         if (nla_put_in_addr(skb, RTA_DST, dst))
2617                 goto nla_put_failure;
2618         if (src) {
2619                 r->rtm_src_len = 32;
2620                 if (nla_put_in_addr(skb, RTA_SRC, src))
2621                         goto nla_put_failure;
2622         }
2623         if (rt->dst.dev &&
2624             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2625                 goto nla_put_failure;
2626 #ifdef CONFIG_IP_ROUTE_CLASSID
2627         if (rt->dst.tclassid &&
2628             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2629                 goto nla_put_failure;
2630 #endif
2631         if (!rt_is_input_route(rt) &&
2632             fl4->saddr != src) {
2633                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2634                         goto nla_put_failure;
2635         }
2636         if (rt->rt_uses_gateway &&
2637             nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2638                 goto nla_put_failure;
2639
2640         expires = rt->dst.expires;
2641         if (expires) {
2642                 unsigned long now = jiffies;
2643
2644                 if (time_before(now, expires))
2645                         expires -= now;
2646                 else
2647                         expires = 0;
2648         }
2649
2650         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2651         if (rt->rt_pmtu && expires)
2652                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2653         if (rt->rt_mtu_locked && expires)
2654                 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2655         if (rtnetlink_put_metrics(skb, metrics) < 0)
2656                 goto nla_put_failure;
2657
2658         if (fl4->flowi4_mark &&
2659             nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2660                 goto nla_put_failure;
2661
2662         if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2663             nla_put_u32(skb, RTA_UID,
2664                         from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2665                 goto nla_put_failure;
2666
2667         error = rt->dst.error;
2668
2669         if (rt_is_input_route(rt)) {
2670 #ifdef CONFIG_IP_MROUTE
2671                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2672                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2673                         int err = ipmr_get_route(net, skb,
2674                                                  fl4->saddr, fl4->daddr,
2675                                                  r, portid);
2676
2677                         if (err <= 0) {
2678                                 if (err == 0)
2679                                         return 0;
2680                                 goto nla_put_failure;
2681                         }
2682                 } else
2683 #endif
2684                         if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2685                                 goto nla_put_failure;
2686         }
2687
2688         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2689                 goto nla_put_failure;
2690
2691         nlmsg_end(skb, nlh);
2692         return 0;
2693
2694 nla_put_failure:
2695         nlmsg_cancel(skb, nlh);
2696         return -EMSGSIZE;
2697 }
2698
2699 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2700                              struct netlink_ext_ack *extack)
2701 {
2702         struct net *net = sock_net(in_skb->sk);
2703         struct rtmsg *rtm;
2704         struct nlattr *tb[RTA_MAX+1];
2705         struct fib_result res = {};
2706         struct rtable *rt = NULL;
2707         struct flowi4 fl4;
2708         __be32 dst = 0;
2709         __be32 src = 0;
2710         u32 iif;
2711         int err;
2712         int mark;
2713         struct sk_buff *skb;
2714         u32 table_id = RT_TABLE_MAIN;
2715         kuid_t uid;
2716
2717         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2718                           extack);
2719         if (err < 0)
2720                 goto errout;
2721
2722         rtm = nlmsg_data(nlh);
2723
2724         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2725         if (!skb) {
2726                 err = -ENOBUFS;
2727                 goto errout;
2728         }
2729
2730         /* Reserve room for dummy headers, this skb can pass
2731            through good chunk of routing engine.
2732          */
2733         skb_reset_mac_header(skb);
2734         skb_reset_network_header(skb);
2735
2736         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2737         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2738         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2739         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2740         if (tb[RTA_UID])
2741                 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2742         else
2743                 uid = (iif ? INVALID_UID : current_uid());
2744
2745         /* Bugfix: need to give ip_route_input enough of an IP header to
2746          * not gag.
2747          */
2748         ip_hdr(skb)->protocol = IPPROTO_UDP;
2749         ip_hdr(skb)->saddr = src;
2750         ip_hdr(skb)->daddr = dst;
2751
2752         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2753
2754         memset(&fl4, 0, sizeof(fl4));
2755         fl4.daddr = dst;
2756         fl4.saddr = src;
2757         fl4.flowi4_tos = rtm->rtm_tos;
2758         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2759         fl4.flowi4_mark = mark;
2760         fl4.flowi4_uid = uid;
2761
2762         rcu_read_lock();
2763
2764         if (iif) {
2765                 struct net_device *dev;
2766
2767                 dev = dev_get_by_index_rcu(net, iif);
2768                 if (!dev) {
2769                         err = -ENODEV;
2770                         goto errout_free;
2771                 }
2772
2773                 skb->protocol   = htons(ETH_P_IP);
2774                 skb->dev        = dev;
2775                 skb->mark       = mark;
2776                 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2777                                          dev, &res);
2778
2779                 rt = skb_rtable(skb);
2780                 if (err == 0 && rt->dst.error)
2781                         err = -rt->dst.error;
2782         } else {
2783                 fl4.flowi4_iif = LOOPBACK_IFINDEX;
2784                 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2785                 err = 0;
2786                 if (IS_ERR(rt))
2787                         err = PTR_ERR(rt);
2788                 else
2789                         skb_dst_set(skb, &rt->dst);
2790         }
2791
2792         if (err)
2793                 goto errout_free;
2794
2795         if (rtm->rtm_flags & RTM_F_NOTIFY)
2796                 rt->rt_flags |= RTCF_NOTIFY;
2797
2798         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2799                 table_id = res.table ? res.table->tb_id : 0;
2800
2801         if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2802                 if (!res.fi) {
2803                         err = fib_props[res.type].error;
2804                         if (!err)
2805                                 err = -EHOSTUNREACH;
2806                         goto errout_free;
2807                 }
2808                 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2809                                     nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2810                                     rt->rt_type, res.prefix, res.prefixlen,
2811                                     fl4.flowi4_tos, res.fi, 0);
2812         } else {
2813                 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2814                                    NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2815         }
2816         if (err < 0)
2817                 goto errout_free;
2818
2819         rcu_read_unlock();
2820
2821         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2822 errout:
2823         return err;
2824
2825 errout_free:
2826         rcu_read_unlock();
2827         kfree_skb(skb);
2828         goto errout;
2829 }
2830
2831 void ip_rt_multicast_event(struct in_device *in_dev)
2832 {
2833         rt_cache_flush(dev_net(in_dev->dev));
2834 }
2835
2836 #ifdef CONFIG_SYSCTL
2837 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
2838 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
2839 static int ip_rt_gc_elasticity __read_mostly    = 8;
2840 static int ip_min_valid_pmtu __read_mostly      = IPV4_MIN_MTU;
2841
2842 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2843                                         void __user *buffer,
2844                                         size_t *lenp, loff_t *ppos)
2845 {
2846         struct net *net = (struct net *)__ctl->extra1;
2847
2848         if (write) {
2849                 rt_cache_flush(net);
2850                 fnhe_genid_bump(net);
2851                 return 0;
2852         }
2853
2854         return -EINVAL;
2855 }
2856
2857 static struct ctl_table ipv4_route_table[] = {
2858         {
2859                 .procname       = "gc_thresh",
2860                 .data           = &ipv4_dst_ops.gc_thresh,
2861                 .maxlen         = sizeof(int),
2862                 .mode           = 0644,
2863                 .proc_handler   = proc_dointvec,
2864         },
2865         {
2866                 .procname       = "max_size",
2867                 .data           = &ip_rt_max_size,
2868                 .maxlen         = sizeof(int),
2869                 .mode           = 0644,
2870                 .proc_handler   = proc_dointvec,
2871         },
2872         {
2873                 /*  Deprecated. Use gc_min_interval_ms */
2874
2875                 .procname       = "gc_min_interval",
2876                 .data           = &ip_rt_gc_min_interval,
2877                 .maxlen         = sizeof(int),
2878                 .mode           = 0644,
2879                 .proc_handler   = proc_dointvec_jiffies,
2880         },
2881         {
2882                 .procname       = "gc_min_interval_ms",
2883                 .data           = &ip_rt_gc_min_interval,
2884                 .maxlen         = sizeof(int),
2885                 .mode           = 0644,
2886                 .proc_handler   = proc_dointvec_ms_jiffies,
2887         },
2888         {
2889                 .procname       = "gc_timeout",
2890                 .data           = &ip_rt_gc_timeout,
2891                 .maxlen         = sizeof(int),
2892                 .mode           = 0644,
2893                 .proc_handler   = proc_dointvec_jiffies,
2894         },
2895         {
2896                 .procname       = "gc_interval",
2897                 .data           = &ip_rt_gc_interval,
2898                 .maxlen         = sizeof(int),
2899                 .mode           = 0644,
2900                 .proc_handler   = proc_dointvec_jiffies,
2901         },
2902         {
2903                 .procname       = "redirect_load",
2904                 .data           = &ip_rt_redirect_load,
2905                 .maxlen         = sizeof(int),
2906                 .mode           = 0644,
2907                 .proc_handler   = proc_dointvec,
2908         },
2909         {
2910                 .procname       = "redirect_number",
2911                 .data           = &ip_rt_redirect_number,
2912                 .maxlen         = sizeof(int),
2913                 .mode           = 0644,
2914                 .proc_handler   = proc_dointvec,
2915         },
2916         {
2917                 .procname       = "redirect_silence",
2918                 .data           = &ip_rt_redirect_silence,
2919                 .maxlen         = sizeof(int),
2920                 .mode           = 0644,
2921                 .proc_handler   = proc_dointvec,
2922         },
2923         {
2924                 .procname       = "error_cost",
2925                 .data           = &ip_rt_error_cost,
2926                 .maxlen         = sizeof(int),
2927                 .mode           = 0644,
2928                 .proc_handler   = proc_dointvec,
2929         },
2930         {
2931                 .procname       = "error_burst",
2932                 .data           = &ip_rt_error_burst,
2933                 .maxlen         = sizeof(int),
2934                 .mode           = 0644,
2935                 .proc_handler   = proc_dointvec,
2936         },
2937         {
2938                 .procname       = "gc_elasticity",
2939                 .data           = &ip_rt_gc_elasticity,
2940                 .maxlen         = sizeof(int),
2941                 .mode           = 0644,
2942                 .proc_handler   = proc_dointvec,
2943         },
2944         {
2945                 .procname       = "mtu_expires",
2946                 .data           = &ip_rt_mtu_expires,
2947                 .maxlen         = sizeof(int),
2948                 .mode           = 0644,
2949                 .proc_handler   = proc_dointvec_jiffies,
2950         },
2951         {
2952                 .procname       = "min_pmtu",
2953                 .data           = &ip_rt_min_pmtu,
2954                 .maxlen         = sizeof(int),
2955                 .mode           = 0644,
2956                 .proc_handler   = proc_dointvec_minmax,
2957                 .extra1         = &ip_min_valid_pmtu,
2958         },
2959         {
2960                 .procname       = "min_adv_mss",
2961                 .data           = &ip_rt_min_advmss,
2962                 .maxlen         = sizeof(int),
2963                 .mode           = 0644,
2964                 .proc_handler   = proc_dointvec,
2965         },
2966         { }
2967 };
2968
2969 static struct ctl_table ipv4_route_flush_table[] = {
2970         {
2971                 .procname       = "flush",
2972                 .maxlen         = sizeof(int),
2973                 .mode           = 0200,
2974                 .proc_handler   = ipv4_sysctl_rtcache_flush,
2975         },
2976         { },
2977 };
2978
2979 static __net_init int sysctl_route_net_init(struct net *net)
2980 {
2981         struct ctl_table *tbl;
2982
2983         tbl = ipv4_route_flush_table;
2984         if (!net_eq(net, &init_net)) {
2985                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2986                 if (!tbl)
2987                         goto err_dup;
2988
2989                 /* Don't export sysctls to unprivileged users */
2990                 if (net->user_ns != &init_user_ns)
2991                         tbl[0].procname = NULL;
2992         }
2993         tbl[0].extra1 = net;
2994
2995         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2996         if (!net->ipv4.route_hdr)
2997                 goto err_reg;
2998         return 0;
2999
3000 err_reg:
3001         if (tbl != ipv4_route_flush_table)
3002                 kfree(tbl);
3003 err_dup:
3004         return -ENOMEM;
3005 }
3006
3007 static __net_exit void sysctl_route_net_exit(struct net *net)
3008 {
3009         struct ctl_table *tbl;
3010
3011         tbl = net->ipv4.route_hdr->ctl_table_arg;
3012         unregister_net_sysctl_table(net->ipv4.route_hdr);
3013         BUG_ON(tbl == ipv4_route_flush_table);
3014         kfree(tbl);
3015 }
3016
3017 static __net_initdata struct pernet_operations sysctl_route_ops = {
3018         .init = sysctl_route_net_init,
3019         .exit = sysctl_route_net_exit,
3020 };
3021 #endif
3022
3023 static __net_init int rt_genid_init(struct net *net)
3024 {
3025         atomic_set(&net->ipv4.rt_genid, 0);
3026         atomic_set(&net->fnhe_genid, 0);
3027         atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3028         return 0;
3029 }
3030
3031 static __net_initdata struct pernet_operations rt_genid_ops = {
3032         .init = rt_genid_init,
3033 };
3034
3035 static int __net_init ipv4_inetpeer_init(struct net *net)
3036 {
3037         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3038
3039         if (!bp)
3040                 return -ENOMEM;
3041         inet_peer_base_init(bp);
3042         net->ipv4.peers = bp;
3043         return 0;
3044 }
3045
3046 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3047 {
3048         struct inet_peer_base *bp = net->ipv4.peers;
3049
3050         net->ipv4.peers = NULL;
3051         inetpeer_invalidate_tree(bp);
3052         kfree(bp);
3053 }
3054
3055 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3056         .init   =       ipv4_inetpeer_init,
3057         .exit   =       ipv4_inetpeer_exit,
3058 };
3059
3060 #ifdef CONFIG_IP_ROUTE_CLASSID
3061 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3062 #endif /* CONFIG_IP_ROUTE_CLASSID */
3063
3064 int __init ip_rt_init(void)
3065 {
3066         int cpu;
3067
3068         ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3069         if (!ip_idents)
3070                 panic("IP: failed to allocate ip_idents\n");
3071
3072         prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3073
3074         ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3075         if (!ip_tstamps)
3076                 panic("IP: failed to allocate ip_tstamps\n");
3077
3078         for_each_possible_cpu(cpu) {
3079                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3080
3081                 INIT_LIST_HEAD(&ul->head);
3082                 spin_lock_init(&ul->lock);
3083         }
3084 #ifdef CONFIG_IP_ROUTE_CLASSID
3085         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3086         if (!ip_rt_acct)
3087                 panic("IP: failed to allocate ip_rt_acct\n");
3088 #endif
3089
3090         ipv4_dst_ops.kmem_cachep =
3091                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3092                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3093
3094         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3095
3096         if (dst_entries_init(&ipv4_dst_ops) < 0)
3097                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3098
3099         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3100                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3101
3102         ipv4_dst_ops.gc_thresh = ~0;
3103         ip_rt_max_size = INT_MAX;
3104
3105         devinet_init();
3106         ip_fib_init();
3107
3108         if (ip_rt_proc_init())
3109                 pr_err("Unable to create route proc files\n");
3110 #ifdef CONFIG_XFRM
3111         xfrm_init();
3112         xfrm4_init();
3113 #endif
3114         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3115                       RTNL_FLAG_DOIT_UNLOCKED);
3116
3117 #ifdef CONFIG_SYSCTL
3118         register_pernet_subsys(&sysctl_route_ops);
3119 #endif
3120         register_pernet_subsys(&rt_genid_ops);
3121         register_pernet_subsys(&ipv4_inetpeer_ops);
3122         return 0;
3123 }
3124
3125 #ifdef CONFIG_SYSCTL
3126 /*
3127  * We really need to sanitize the damn ipv4 init order, then all
3128  * this nonsense will go away.
3129  */
3130 void __init ip_static_sysctl_init(void)
3131 {
3132         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3133 }
3134 #endif