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", S_IRUGO, net->proc_net,
 383                           &rt_cache_seq_fops);
 384         if (!pde)
 385                 goto err1;
 386
 387         pde = proc_create("rt_cache", S_IRUGO,
 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->dst.expires = fnhe->fnhe_expires;
 638
 639         if (fnhe->fnhe_gw) {
 640                 rt->rt_flags |= RTCF_REDIRECTED;
 641                 rt->rt_gateway = fnhe->fnhe_gw;
 642                 rt->rt_uses_gateway = 1;
 643         }
 644 }
 645
 646 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
 647                                   u32 pmtu, unsigned long expires)
 648 {
 649         struct fnhe_hash_bucket *hash;
 650         struct fib_nh_exception *fnhe;
 651         struct rtable *rt;
 652         u32 genid, hval;
 653         unsigned int i;
 654         int depth;
 655
 656         genid = fnhe_genid(dev_net(nh->nh_dev));
 657         hval = fnhe_hashfun(daddr);
 658
 659         spin_lock_bh(&fnhe_lock);
 660
 661         hash = rcu_dereference(nh->nh_exceptions);
 662         if (!hash) {
 663                 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
 664                 if (!hash)
 665                         goto out_unlock;
 666                 rcu_assign_pointer(nh->nh_exceptions, hash);
 667         }
 668
 669         hash += hval;
 670
 671         depth = 0;
 672         for (fnhe = rcu_dereference(hash->chain); fnhe;
 673              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 674                 if (fnhe->fnhe_daddr == daddr)
 675                         break;
 676                 depth++;
 677         }
 678
 679         if (fnhe) {
 680                 if (fnhe->fnhe_genid != genid)
 681                         fnhe->fnhe_genid = genid;
 682                 if (gw)
 683                         fnhe->fnhe_gw = gw;
 684                 if (pmtu)
 685                         fnhe->fnhe_pmtu = pmtu;
 686                 fnhe->fnhe_expires = max(1UL, expires);
 687                 /* Update all cached dsts too */
 688                 rt = rcu_dereference(fnhe->fnhe_rth_input);
 689                 if (rt)
 690                         fill_route_from_fnhe(rt, fnhe);
 691                 rt = rcu_dereference(fnhe->fnhe_rth_output);
 692                 if (rt)
 693                         fill_route_from_fnhe(rt, fnhe);
 694         } else {
 695                 if (depth > FNHE_RECLAIM_DEPTH)
 696                         fnhe = fnhe_oldest(hash);
 697                 else {
 698                         fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
 699                         if (!fnhe)
 700                                 goto out_unlock;
 701
 702                         fnhe->fnhe_next = hash->chain;
 703                         rcu_assign_pointer(hash->chain, fnhe);
 704                 }
 705                 fnhe->fnhe_genid = genid;
 706                 fnhe->fnhe_daddr = daddr;
 707                 fnhe->fnhe_gw = gw;
 708                 fnhe->fnhe_pmtu = pmtu;
 709                 fnhe->fnhe_expires = expires;
 710
 711                 /* Exception created; mark the cached routes for the nexthop
 712                  * stale, so anyone caching it rechecks if this exception
 713                  * applies to them.
 714                  */
 715                 rt = rcu_dereference(nh->nh_rth_input);
 716                 if (rt)
 717                         rt->dst.obsolete = DST_OBSOLETE_KILL;
 718
 719                 for_each_possible_cpu(i) {
 720                         struct rtable __rcu **prt;
 721                         prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
 722                         rt = rcu_dereference(*prt);
 723                         if (rt)
 724                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 725                 }
 726         }
 727
 728         fnhe->fnhe_stamp = jiffies;
 729
 730 out_unlock:
 731         spin_unlock_bh(&fnhe_lock);
 732 }
 733
 734 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 735                              bool kill_route)
 736 {
 737         __be32 new_gw = icmp_hdr(skb)->un.gateway;
 738         __be32 old_gw = ip_hdr(skb)->saddr;
 739         struct net_device *dev = skb->dev;
 740         struct in_device *in_dev;
 741         struct fib_result res;
 742         struct neighbour *n;
 743         struct net *net;
 744
 745         switch (icmp_hdr(skb)->code & 7) {
 746         case ICMP_REDIR_NET:
 747         case ICMP_REDIR_NETTOS:
 748         case ICMP_REDIR_HOST:
 749         case ICMP_REDIR_HOSTTOS:
 750                 break;
 751
 752         default:
 753                 return;
 754         }
 755
 756         if (rt->rt_gateway != old_gw)
 757                 return;
 758
 759         in_dev = __in_dev_get_rcu(dev);
 760         if (!in_dev)
 761                 return;
 762
 763         net = dev_net(dev);
 764         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
 765             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
 766             ipv4_is_zeronet(new_gw))
 767                 goto reject_redirect;
 768
 769         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
 770                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
 771                         goto reject_redirect;
 772                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
 773                         goto reject_redirect;
 774         } else {
 775                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
 776                         goto reject_redirect;
 777         }
 778
 779         n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
 780         if (!n)
 781                 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
 782         if (!IS_ERR(n)) {
 783                 if (!(n->nud_state & NUD_VALID)) {
 784                         neigh_event_send(n, NULL);
 785                 } else {
 786                         if (fib_lookup(net, fl4, &res, 0) == 0) {
 787                                 struct fib_nh *nh = &FIB_RES_NH(res);
 788
 789                                 update_or_create_fnhe(nh, fl4->daddr, new_gw,
 790                                                 0, jiffies + ip_rt_gc_timeout);
 791                         }
 792                         if (kill_route)
 793                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 794                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 795                 }
 796                 neigh_release(n);
 797         }
 798         return;
 799
 800 reject_redirect:
 801 #ifdef CONFIG_IP_ROUTE_VERBOSE
 802         if (IN_DEV_LOG_MARTIANS(in_dev)) {
 803                 const struct iphdr *iph = (const struct iphdr *) skb->data;
 804                 __be32 daddr = iph->daddr;
 805                 __be32 saddr = iph->saddr;
 806
 807                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
 808                                      "  Advised path = %pI4 -> %pI4\n",
 809                                      &old_gw, dev->name, &new_gw,
 810                                      &saddr, &daddr);
 811         }
 812 #endif
 813         ;
 814 }
 815
 816 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
 817 {
 818         struct rtable *rt;
 819         struct flowi4 fl4;
 820         const struct iphdr *iph = (const struct iphdr *) skb->data;
 821         struct net *net = dev_net(skb->dev);
 822         int oif = skb->dev->ifindex;
 823         u8 tos = RT_TOS(iph->tos);
 824         u8 prot = iph->protocol;
 825         u32 mark = skb->mark;
 826
 827         rt = (struct rtable *) dst;
 828
 829         __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
 830         __ip_do_redirect(rt, skb, &fl4, true);
 831 }
 832
 833 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 834 {
 835         struct rtable *rt = (struct rtable *)dst;
 836         struct dst_entry *ret = dst;
 837
 838         if (rt) {
 839                 if (dst->obsolete > 0) {
 840                         ip_rt_put(rt);
 841                         ret = NULL;
 842                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
 843                            rt->dst.expires) {
 844                         ip_rt_put(rt);
 845                         ret = NULL;
 846                 }
 847         }
 848         return ret;
 849 }
 850
 851 /*
 852  * Algorithm:
 853  *      1. The first ip_rt_redirect_number redirects are sent
 854  *         with exponential backoff, then we stop sending them at all,
 855  *         assuming that the host ignores our redirects.
 856  *      2. If we did not see packets requiring redirects
 857  *         during ip_rt_redirect_silence, we assume that the host
 858  *         forgot redirected route and start to send redirects again.
 859  *
 860  * This algorithm is much cheaper and more intelligent than dumb load limiting
 861  * in icmp.c.
 862  *
 863  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 864  * and "frag. need" (breaks PMTU discovery) in icmp.c.
 865  */
 866
 867 void ip_rt_send_redirect(struct sk_buff *skb)
 868 {
 869         struct rtable *rt = skb_rtable(skb);
 870         struct in_device *in_dev;
 871         struct inet_peer *peer;
 872         struct net *net;
 873         int log_martians;
 874         int vif;
 875
 876         rcu_read_lock();
 877         in_dev = __in_dev_get_rcu(rt->dst.dev);
 878         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
 879                 rcu_read_unlock();
 880                 return;
 881         }
 882         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
 883         vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
 884         rcu_read_unlock();
 885
 886         net = dev_net(rt->dst.dev);
 887         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
 888         if (!peer) {
 889                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
 890                           rt_nexthop(rt, ip_hdr(skb)->daddr));
 891                 return;
 892         }
 893
 894         /* No redirected packets during ip_rt_redirect_silence;
 895          * reset the algorithm.
 896          */
 897         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
 898                 peer->rate_tokens = 0;
 899
 900         /* Too many ignored redirects; do not send anything
 901          * set dst.rate_last to the last seen redirected packet.
 902          */
 903         if (peer->rate_tokens >= ip_rt_redirect_number) {
 904                 peer->rate_last = jiffies;
 905                 goto out_put_peer;
 906         }
 907
 908         /* Check for load limit; set rate_last to the latest sent
 909          * redirect.
 910          */
 911         if (peer->rate_tokens == 0 ||
 912             time_after(jiffies,
 913                        (peer->rate_last +
 914                         (ip_rt_redirect_load << peer->rate_tokens)))) {
 915                 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
 916
 917                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 918                 peer->rate_last = jiffies;
 919                 ++peer->rate_tokens;
 920 #ifdef CONFIG_IP_ROUTE_VERBOSE
 921                 if (log_martians &&
 922                     peer->rate_tokens == ip_rt_redirect_number)
 923                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 924                                              &ip_hdr(skb)->saddr, inet_iif(skb),
 925                                              &ip_hdr(skb)->daddr, &gw);
 926 #endif
 927         }
 928 out_put_peer:
 929         inet_putpeer(peer);
 930 }
 931
 932 static int ip_error(struct sk_buff *skb)
 933 {
 934         struct rtable *rt = skb_rtable(skb);
 935         struct net_device *dev = skb->dev;
 936         struct in_device *in_dev;
 937         struct inet_peer *peer;
 938         unsigned long now;
 939         struct net *net;
 940         bool send;
 941         int code;
 942
 943         if (netif_is_l3_master(skb->dev)) {
 944                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
 945                 if (!dev)
 946                         goto out;
 947         }
 948
 949         in_dev = __in_dev_get_rcu(dev);
 950
 951         /* IP on this device is disabled. */
 952         if (!in_dev)
 953                 goto out;
 954
 955         net = dev_net(rt->dst.dev);
 956         if (!IN_DEV_FORWARD(in_dev)) {
 957                 switch (rt->dst.error) {
 958                 case EHOSTUNREACH:
 959                         __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
 960                         break;
 961
 962                 case ENETUNREACH:
 963                         __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 964                         break;
 965                 }
 966                 goto out;
 967         }
 968
 969         switch (rt->dst.error) {
 970         case EINVAL:
 971         default:
 972                 goto out;
 973         case EHOSTUNREACH:
 974                 code = ICMP_HOST_UNREACH;
 975                 break;
 976         case ENETUNREACH:
 977                 code = ICMP_NET_UNREACH;
 978                 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 979                 break;
 980         case EACCES:
 981                 code = ICMP_PKT_FILTERED;
 982                 break;
 983         }
 984
 985         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
 986                                l3mdev_master_ifindex(skb->dev), 1);
 987
 988         send = true;
 989         if (peer) {
 990                 now = jiffies;
 991                 peer->rate_tokens += now - peer->rate_last;
 992                 if (peer->rate_tokens > ip_rt_error_burst)
 993                         peer->rate_tokens = ip_rt_error_burst;
 994                 peer->rate_last = now;
 995                 if (peer->rate_tokens >= ip_rt_error_cost)
 996                         peer->rate_tokens -= ip_rt_error_cost;
 997                 else
 998                         send = false;
 999                 inet_putpeer(peer);
1000         }
1001         if (send)
1002                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1003
1004 out:    kfree_skb(skb);
1005         return 0;
1006 }
1007
1008 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1009 {
1010         struct dst_entry *dst = &rt->dst;
1011         struct fib_result res;
1012
1013         if (dst_metric_locked(dst, RTAX_MTU))
1014                 return;
1015
1016         if (ipv4_mtu(dst) < mtu)
1017                 return;
1018
1019         if (mtu < ip_rt_min_pmtu)
1020                 mtu = ip_rt_min_pmtu;
1021
1022         if (rt->rt_pmtu == mtu &&
1023             time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1024                 return;
1025
1026         rcu_read_lock();
1027         if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1028                 struct fib_nh *nh = &FIB_RES_NH(res);
1029
1030                 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1031                                       jiffies + ip_rt_mtu_expires);
1032         }
1033         rcu_read_unlock();
1034 }
1035
1036 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1037                               struct sk_buff *skb, u32 mtu)
1038 {
1039         struct rtable *rt = (struct rtable *) dst;
1040         struct flowi4 fl4;
1041
1042         ip_rt_build_flow_key(&fl4, sk, skb);
1043         __ip_rt_update_pmtu(rt, &fl4, mtu);
1044 }
1045
1046 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1047                       int oif, u32 mark, u8 protocol, int flow_flags)
1048 {
1049         const struct iphdr *iph = (const struct iphdr *) skb->data;
1050         struct flowi4 fl4;
1051         struct rtable *rt;
1052
1053         if (!mark)
1054                 mark = IP4_REPLY_MARK(net, skb->mark);
1055
1056         __build_flow_key(net, &fl4, NULL, iph, oif,
1057                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1058         rt = __ip_route_output_key(net, &fl4);
1059         if (!IS_ERR(rt)) {
1060                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1061                 ip_rt_put(rt);
1062         }
1063 }
1064 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1065
1066 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1067 {
1068         const struct iphdr *iph = (const struct iphdr *) skb->data;
1069         struct flowi4 fl4;
1070         struct rtable *rt;
1071
1072         __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1073
1074         if (!fl4.flowi4_mark)
1075                 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1076
1077         rt = __ip_route_output_key(sock_net(sk), &fl4);
1078         if (!IS_ERR(rt)) {
1079                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1080                 ip_rt_put(rt);
1081         }
1082 }
1083
1084 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1085 {
1086         const struct iphdr *iph = (const struct iphdr *) skb->data;
1087         struct flowi4 fl4;
1088         struct rtable *rt;
1089         struct dst_entry *odst = NULL;
1090         bool new = false;
1091         struct net *net = sock_net(sk);
1092
1093         bh_lock_sock(sk);
1094
1095         if (!ip_sk_accept_pmtu(sk))
1096                 goto out;
1097
1098         odst = sk_dst_get(sk);
1099
1100         if (sock_owned_by_user(sk) || !odst) {
1101                 __ipv4_sk_update_pmtu(skb, sk, mtu);
1102                 goto out;
1103         }
1104
1105         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1106
1107         rt = (struct rtable *)odst;
1108         if (odst->obsolete && !odst->ops->check(odst, 0)) {
1109                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1110                 if (IS_ERR(rt))
1111                         goto out;
1112
1113                 new = true;
1114         }
1115
1116         __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1117
1118         if (!dst_check(&rt->dst, 0)) {
1119                 if (new)
1120                         dst_release(&rt->dst);
1121
1122                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1123                 if (IS_ERR(rt))
1124                         goto out;
1125
1126                 new = true;
1127         }
1128
1129         if (new)
1130                 sk_dst_set(sk, &rt->dst);
1131
1132 out:
1133         bh_unlock_sock(sk);
1134         dst_release(odst);
1135 }
1136 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1137
1138 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1139                    int oif, u32 mark, u8 protocol, int flow_flags)
1140 {
1141         const struct iphdr *iph = (const struct iphdr *) skb->data;
1142         struct flowi4 fl4;
1143         struct rtable *rt;
1144
1145         __build_flow_key(net, &fl4, NULL, iph, oif,
1146                          RT_TOS(iph->tos), protocol, mark, flow_flags);
1147         rt = __ip_route_output_key(net, &fl4);
1148         if (!IS_ERR(rt)) {
1149                 __ip_do_redirect(rt, skb, &fl4, false);
1150                 ip_rt_put(rt);
1151         }
1152 }
1153 EXPORT_SYMBOL_GPL(ipv4_redirect);
1154
1155 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1156 {
1157         const struct iphdr *iph = (const struct iphdr *) skb->data;
1158         struct flowi4 fl4;
1159         struct rtable *rt;
1160         struct net *net = sock_net(sk);
1161
1162         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1163         rt = __ip_route_output_key(net, &fl4);
1164         if (!IS_ERR(rt)) {
1165                 __ip_do_redirect(rt, skb, &fl4, false);
1166                 ip_rt_put(rt);
1167         }
1168 }
1169 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1170
1171 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1172 {
1173         struct rtable *rt = (struct rtable *) dst;
1174
1175         /* All IPV4 dsts are created with ->obsolete set to the value
1176          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1177          * into this function always.
1178          *
1179          * When a PMTU/redirect information update invalidates a route,
1180          * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1181          * DST_OBSOLETE_DEAD by dst_free().
1182          */
1183         if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1184                 return NULL;
1185         return dst;
1186 }
1187
1188 static void ipv4_link_failure(struct sk_buff *skb)
1189 {
1190         struct rtable *rt;
1191
1192         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1193
1194         rt = skb_rtable(skb);
1195         if (rt)
1196                 dst_set_expires(&rt->dst, 0);
1197 }
1198
1199 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1200 {
1201         pr_debug("%s: %pI4 -> %pI4, %s\n",
1202                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1203                  skb->dev ? skb->dev->name : "?");
1204         kfree_skb(skb);
1205         WARN_ON(1);
1206         return 0;
1207 }
1208
1209 /*
1210    We do not cache source address of outgoing interface,
1211    because it is used only by IP RR, TS and SRR options,
1212    so that it out of fast path.
1213
1214    BTW remember: "addr" is allowed to be not aligned
1215    in IP options!
1216  */
1217
1218 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1219 {
1220         __be32 src;
1221
1222         if (rt_is_output_route(rt))
1223                 src = ip_hdr(skb)->saddr;
1224         else {
1225                 struct fib_result res;
1226                 struct flowi4 fl4;
1227                 struct iphdr *iph;
1228
1229                 iph = ip_hdr(skb);
1230
1231                 memset(&fl4, 0, sizeof(fl4));
1232                 fl4.daddr = iph->daddr;
1233                 fl4.saddr = iph->saddr;
1234                 fl4.flowi4_tos = RT_TOS(iph->tos);
1235                 fl4.flowi4_oif = rt->dst.dev->ifindex;
1236                 fl4.flowi4_iif = skb->dev->ifindex;
1237                 fl4.flowi4_mark = skb->mark;
1238
1239                 rcu_read_lock();
1240                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1241                         src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1242                 else
1243                         src = inet_select_addr(rt->dst.dev,
1244                                                rt_nexthop(rt, iph->daddr),
1245                                                RT_SCOPE_UNIVERSE);
1246                 rcu_read_unlock();
1247         }
1248         memcpy(addr, &src, 4);
1249 }
1250
1251 #ifdef CONFIG_IP_ROUTE_CLASSID
1252 static void set_class_tag(struct rtable *rt, u32 tag)
1253 {
1254         if (!(rt->dst.tclassid & 0xFFFF))
1255                 rt->dst.tclassid |= tag & 0xFFFF;
1256         if (!(rt->dst.tclassid & 0xFFFF0000))
1257                 rt->dst.tclassid |= tag & 0xFFFF0000;
1258 }
1259 #endif
1260
1261 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1262 {
1263         unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1264         unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1265                                     ip_rt_min_advmss);
1266
1267         return min(advmss, IPV4_MAX_PMTU - header_size);
1268 }
1269
1270 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1271 {
1272         const struct rtable *rt = (const struct rtable *) dst;
1273         unsigned int mtu = rt->rt_pmtu;
1274
1275         if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1276                 mtu = dst_metric_raw(dst, RTAX_MTU);
1277
1278         if (mtu)
1279                 return mtu;
1280
1281         mtu = READ_ONCE(dst->dev->mtu);
1282
1283         if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1284                 if (rt->rt_uses_gateway && mtu > 576)
1285                         mtu = 576;
1286         }
1287
1288         mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1289
1290         return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1291 }
1292
1293 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1294 {
1295         struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1296         struct fib_nh_exception *fnhe;
1297         u32 hval;
1298
1299         if (!hash)
1300                 return NULL;
1301
1302         hval = fnhe_hashfun(daddr);
1303
1304         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1305              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1306                 if (fnhe->fnhe_daddr == daddr)
1307                         return fnhe;
1308         }
1309         return NULL;
1310 }
1311
1312 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1313                               __be32 daddr, const bool do_cache)
1314 {
1315         bool ret = false;
1316
1317         spin_lock_bh(&fnhe_lock);
1318
1319         if (daddr == fnhe->fnhe_daddr) {
1320                 struct rtable __rcu **porig;
1321                 struct rtable *orig;
1322                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1323
1324                 if (rt_is_input_route(rt))
1325                         porig = &fnhe->fnhe_rth_input;
1326                 else
1327                         porig = &fnhe->fnhe_rth_output;
1328                 orig = rcu_dereference(*porig);
1329
1330                 if (fnhe->fnhe_genid != genid) {
1331                         fnhe->fnhe_genid = genid;
1332                         fnhe->fnhe_gw = 0;
1333                         fnhe->fnhe_pmtu = 0;
1334                         fnhe->fnhe_expires = 0;
1335                         fnhe_flush_routes(fnhe);
1336                         orig = NULL;
1337                 }
1338                 fill_route_from_fnhe(rt, fnhe);
1339                 if (!rt->rt_gateway)
1340                         rt->rt_gateway = daddr;
1341
1342                 if (do_cache) {
1343                         dst_hold(&rt->dst);
1344                         rcu_assign_pointer(*porig, rt);
1345                         if (orig) {
1346                                 dst_dev_put(&orig->dst);
1347                                 dst_release(&orig->dst);
1348                         }
1349                         ret = true;
1350                 }
1351
1352                 fnhe->fnhe_stamp = jiffies;
1353         }
1354         spin_unlock_bh(&fnhe_lock);
1355
1356         return ret;
1357 }
1358
1359 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1360 {
1361         struct rtable *orig, *prev, **p;
1362         bool ret = true;
1363
1364         if (rt_is_input_route(rt)) {
1365                 p = (struct rtable **)&nh->nh_rth_input;
1366         } else {
1367                 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1368         }
1369         orig = *p;
1370
1371         /* hold dst before doing cmpxchg() to avoid race condition
1372          * on this dst
1373          */
1374         dst_hold(&rt->dst);
1375         prev = cmpxchg(p, orig, rt);
1376         if (prev == orig) {
1377                 if (orig) {
1378                         dst_dev_put(&orig->dst);
1379                         dst_release(&orig->dst);
1380                 }
1381         } else {
1382                 dst_release(&rt->dst);
1383                 ret = false;
1384         }
1385
1386         return ret;
1387 }
1388
1389 struct uncached_list {
1390         spinlock_t              lock;
1391         struct list_head        head;
1392 };
1393
1394 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1395
1396 void rt_add_uncached_list(struct rtable *rt)
1397 {
1398         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1399
1400         rt->rt_uncached_list = ul;
1401
1402         spin_lock_bh(&ul->lock);
1403         list_add_tail(&rt->rt_uncached, &ul->head);
1404         spin_unlock_bh(&ul->lock);
1405 }
1406
1407 void rt_del_uncached_list(struct rtable *rt)
1408 {
1409         if (!list_empty(&rt->rt_uncached)) {
1410                 struct uncached_list *ul = rt->rt_uncached_list;
1411
1412                 spin_lock_bh(&ul->lock);
1413                 list_del(&rt->rt_uncached);
1414                 spin_unlock_bh(&ul->lock);
1415         }
1416 }
1417
1418 static void ipv4_dst_destroy(struct dst_entry *dst)
1419 {
1420         struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1421         struct rtable *rt = (struct rtable *)dst;
1422
1423         if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1424                 kfree(p);
1425
1426         rt_del_uncached_list(rt);
1427 }
1428
1429 void rt_flush_dev(struct net_device *dev)
1430 {
1431         struct net *net = dev_net(dev);
1432         struct rtable *rt;
1433         int cpu;
1434
1435         for_each_possible_cpu(cpu) {
1436                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1437
1438                 spin_lock_bh(&ul->lock);
1439                 list_for_each_entry(rt, &ul->head, rt_uncached) {
1440                         if (rt->dst.dev != dev)
1441                                 continue;
1442                         rt->dst.dev = net->loopback_dev;
1443                         dev_hold(rt->dst.dev);
1444                         dev_put(dev);
1445                 }
1446                 spin_unlock_bh(&ul->lock);
1447         }
1448 }
1449
1450 static bool rt_cache_valid(const struct rtable *rt)
1451 {
1452         return  rt &&
1453                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1454                 !rt_is_expired(rt);
1455 }
1456
1457 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1458                            const struct fib_result *res,
1459                            struct fib_nh_exception *fnhe,
1460                            struct fib_info *fi, u16 type, u32 itag,
1461                            const bool do_cache)
1462 {
1463         bool cached = false;
1464
1465         if (fi) {
1466                 struct fib_nh *nh = &FIB_RES_NH(*res);
1467
1468                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1469                         rt->rt_gateway = nh->nh_gw;
1470                         rt->rt_uses_gateway = 1;
1471                 }
1472                 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1473                 if (fi->fib_metrics != &dst_default_metrics) {
1474                         rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1475                         refcount_inc(&fi->fib_metrics->refcnt);
1476                 }
1477 #ifdef CONFIG_IP_ROUTE_CLASSID
1478                 rt->dst.tclassid = nh->nh_tclassid;
1479 #endif
1480                 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1481                 if (unlikely(fnhe))
1482                         cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1483                 else if (do_cache)
1484                         cached = rt_cache_route(nh, rt);
1485                 if (unlikely(!cached)) {
1486                         /* Routes we intend to cache in nexthop exception or
1487                          * FIB nexthop have the DST_NOCACHE bit clear.
1488                          * However, if we are unsuccessful at storing this
1489                          * route into the cache we really need to set it.
1490                          */
1491                         if (!rt->rt_gateway)
1492                                 rt->rt_gateway = daddr;
1493                         rt_add_uncached_list(rt);
1494                 }
1495         } else
1496                 rt_add_uncached_list(rt);
1497
1498 #ifdef CONFIG_IP_ROUTE_CLASSID
1499 #ifdef CONFIG_IP_MULTIPLE_TABLES
1500         set_class_tag(rt, res->tclassid);
1501 #endif
1502         set_class_tag(rt, itag);
1503 #endif
1504 }
1505
1506 struct rtable *rt_dst_alloc(struct net_device *dev,
1507                             unsigned int flags, u16 type,
1508                             bool nopolicy, bool noxfrm, bool will_cache)
1509 {
1510         struct rtable *rt;
1511
1512         rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1513                        (will_cache ? 0 : DST_HOST) |
1514                        (nopolicy ? DST_NOPOLICY : 0) |
1515                        (noxfrm ? DST_NOXFRM : 0));
1516
1517         if (rt) {
1518                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1519                 rt->rt_flags = flags;
1520                 rt->rt_type = type;
1521                 rt->rt_is_input = 0;
1522                 rt->rt_iif = 0;
1523                 rt->rt_pmtu = 0;
1524                 rt->rt_gateway = 0;
1525                 rt->rt_uses_gateway = 0;
1526                 rt->rt_table_id = 0;
1527                 INIT_LIST_HEAD(&rt->rt_uncached);
1528
1529                 rt->dst.output = ip_output;
1530                 if (flags & RTCF_LOCAL)
1531                         rt->dst.input = ip_local_deliver;
1532         }
1533
1534         return rt;
1535 }
1536 EXPORT_SYMBOL(rt_dst_alloc);
1537
1538 /* called in rcu_read_lock() section */
1539 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1540                           u8 tos, struct net_device *dev,
1541                           struct in_device *in_dev, u32 *itag)
1542 {
1543         int err;
1544
1545         /* Primary sanity checks. */
1546         if (!in_dev)
1547                 return -EINVAL;
1548
1549         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1550             skb->protocol != htons(ETH_P_IP))
1551                 return -EINVAL;
1552
1553         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1554                 return -EINVAL;
1555
1556         if (ipv4_is_zeronet(saddr)) {
1557                 if (!ipv4_is_local_multicast(daddr))
1558                         return -EINVAL;
1559         } else {
1560                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1561                                           in_dev, itag);
1562                 if (err < 0)
1563                         return err;
1564         }
1565         return 0;
1566 }
1567
1568 /* called in rcu_read_lock() section */
1569 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1570                              u8 tos, struct net_device *dev, int our)
1571 {
1572         struct in_device *in_dev = __in_dev_get_rcu(dev);
1573         unsigned int flags = RTCF_MULTICAST;
1574         struct rtable *rth;
1575         u32 itag = 0;
1576         int err;
1577
1578         err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1579         if (err)
1580                 return err;
1581
1582         if (our)
1583                 flags |= RTCF_LOCAL;
1584
1585         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1586                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1587         if (!rth)
1588                 return -ENOBUFS;
1589
1590 #ifdef CONFIG_IP_ROUTE_CLASSID
1591         rth->dst.tclassid = itag;
1592 #endif
1593         rth->dst.output = ip_rt_bug;
1594         rth->rt_is_input= 1;
1595
1596 #ifdef CONFIG_IP_MROUTE
1597         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1598                 rth->dst.input = ip_mr_input;
1599 #endif
1600         RT_CACHE_STAT_INC(in_slow_mc);
1601
1602         skb_dst_set(skb, &rth->dst);
1603         return 0;
1604 }
1605
1606
1607 static void ip_handle_martian_source(struct net_device *dev,
1608                                      struct in_device *in_dev,
1609                                      struct sk_buff *skb,
1610                                      __be32 daddr,
1611                                      __be32 saddr)
1612 {
1613         RT_CACHE_STAT_INC(in_martian_src);
1614 #ifdef CONFIG_IP_ROUTE_VERBOSE
1615         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1616                 /*
1617                  *      RFC1812 recommendation, if source is martian,
1618                  *      the only hint is MAC header.
1619                  */
1620                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1621                         &daddr, &saddr, dev->name);
1622                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1623                         print_hex_dump(KERN_WARNING, "ll header: ",
1624                                        DUMP_PREFIX_OFFSET, 16, 1,
1625                                        skb_mac_header(skb),
1626                                        dev->hard_header_len, true);
1627                 }
1628         }
1629 #endif
1630 }
1631
1632 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1633 {
1634         struct fnhe_hash_bucket *hash;
1635         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1636         u32 hval = fnhe_hashfun(daddr);
1637
1638         spin_lock_bh(&fnhe_lock);
1639
1640         hash = rcu_dereference_protected(nh->nh_exceptions,
1641                                          lockdep_is_held(&fnhe_lock));
1642         hash += hval;
1643
1644         fnhe_p = &hash->chain;
1645         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1646         while (fnhe) {
1647                 if (fnhe->fnhe_daddr == daddr) {
1648                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1649                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1650                         fnhe_flush_routes(fnhe);
1651                         kfree_rcu(fnhe, rcu);
1652                         break;
1653                 }
1654                 fnhe_p = &fnhe->fnhe_next;
1655                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1656                                                  lockdep_is_held(&fnhe_lock));
1657         }
1658
1659         spin_unlock_bh(&fnhe_lock);
1660 }
1661
1662 static void set_lwt_redirect(struct rtable *rth)
1663 {
1664         if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1665                 rth->dst.lwtstate->orig_output = rth->dst.output;
1666                 rth->dst.output = lwtunnel_output;
1667         }
1668
1669         if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1670                 rth->dst.lwtstate->orig_input = rth->dst.input;
1671                 rth->dst.input = lwtunnel_input;
1672         }
1673 }
1674
1675 /* called in rcu_read_lock() section */
1676 static int __mkroute_input(struct sk_buff *skb,
1677                            const struct fib_result *res,
1678                            struct in_device *in_dev,
1679                            __be32 daddr, __be32 saddr, u32 tos)
1680 {
1681         struct fib_nh_exception *fnhe;
1682         struct rtable *rth;
1683         int err;
1684         struct in_device *out_dev;
1685         bool do_cache;
1686         u32 itag = 0;
1687
1688         /* get a working reference to the output device */
1689         out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1690         if (!out_dev) {
1691                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1692                 return -EINVAL;
1693         }
1694
1695         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1696                                   in_dev->dev, in_dev, &itag);
1697         if (err < 0) {
1698                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1699                                          saddr);
1700
1701                 goto cleanup;
1702         }
1703
1704         do_cache = res->fi && !itag;
1705         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1706             skb->protocol == htons(ETH_P_IP) &&
1707             (IN_DEV_SHARED_MEDIA(out_dev) ||
1708              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1709                 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1710
1711         if (skb->protocol != htons(ETH_P_IP)) {
1712                 /* Not IP (i.e. ARP). Do not create route, if it is
1713                  * invalid for proxy arp. DNAT routes are always valid.
1714                  *
1715                  * Proxy arp feature have been extended to allow, ARP
1716                  * replies back to the same interface, to support
1717                  * Private VLAN switch technologies. See arp.c.
1718                  */
1719                 if (out_dev == in_dev &&
1720                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1721                         err = -EINVAL;
1722                         goto cleanup;
1723                 }
1724         }
1725
1726         fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1727         if (do_cache) {
1728                 if (fnhe) {
1729                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1730                         if (rth && rth->dst.expires &&
1731                             time_after(jiffies, rth->dst.expires)) {
1732                                 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1733                                 fnhe = NULL;
1734                         } else {
1735                                 goto rt_cache;
1736                         }
1737                 }
1738
1739                 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1740
1741 rt_cache:
1742                 if (rt_cache_valid(rth)) {
1743                         skb_dst_set_noref(skb, &rth->dst);
1744                         goto out;
1745                 }
1746         }
1747
1748         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1749                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
1750                            IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1751         if (!rth) {
1752                 err = -ENOBUFS;
1753                 goto cleanup;
1754         }
1755
1756         rth->rt_is_input = 1;
1757         if (res->table)
1758                 rth->rt_table_id = res->table->tb_id;
1759         RT_CACHE_STAT_INC(in_slow_tot);
1760
1761         rth->dst.input = ip_forward;
1762
1763         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1764                        do_cache);
1765         set_lwt_redirect(rth);
1766         skb_dst_set(skb, &rth->dst);
1767 out:
1768         err = 0;
1769  cleanup:
1770         return err;
1771 }
1772
1773 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1774 /* To make ICMP packets follow the right flow, the multipath hash is
1775  * calculated from the inner IP addresses.
1776  */
1777 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1778                                  struct flow_keys *hash_keys)
1779 {
1780         const struct iphdr *outer_iph = ip_hdr(skb);
1781         const struct iphdr *inner_iph;
1782         const struct icmphdr *icmph;
1783         struct iphdr _inner_iph;
1784         struct icmphdr _icmph;
1785
1786         hash_keys->addrs.v4addrs.src = outer_iph->saddr;
1787         hash_keys->addrs.v4addrs.dst = outer_iph->daddr;
1788         if (likely(outer_iph->protocol != IPPROTO_ICMP))
1789                 return;
1790
1791         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1792                 return;
1793
1794         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1795                                    &_icmph);
1796         if (!icmph)
1797                 return;
1798
1799         if (icmph->type != ICMP_DEST_UNREACH &&
1800             icmph->type != ICMP_REDIRECT &&
1801             icmph->type != ICMP_TIME_EXCEEDED &&
1802             icmph->type != ICMP_PARAMETERPROB)
1803                 return;
1804
1805         inner_iph = skb_header_pointer(skb,
1806                                        outer_iph->ihl * 4 + sizeof(_icmph),
1807                                        sizeof(_inner_iph), &_inner_iph);
1808         if (!inner_iph)
1809                 return;
1810         hash_keys->addrs.v4addrs.src = inner_iph->saddr;
1811         hash_keys->addrs.v4addrs.dst = inner_iph->daddr;
1812 }
1813
1814 /* if skb is set it will be used and fl4 can be NULL */
1815 int fib_multipath_hash(const struct fib_info *fi, const struct flowi4 *fl4,
1816                        const struct sk_buff *skb)
1817 {
1818         struct net *net = fi->fib_net;
1819         struct flow_keys hash_keys;
1820         u32 mhash;
1821
1822         switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1823         case 0:
1824                 memset(&hash_keys, 0, sizeof(hash_keys));
1825                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1826                 if (skb) {
1827                         ip_multipath_l3_keys(skb, &hash_keys);
1828                 } else {
1829                         hash_keys.addrs.v4addrs.src = fl4->saddr;
1830                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
1831                 }
1832                 break;
1833         case 1:
1834                 /* skb is currently provided only when forwarding */
1835                 if (skb) {
1836                         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1837                         struct flow_keys keys;
1838
1839                         /* short-circuit if we already have L4 hash present */
1840                         if (skb->l4_hash)
1841                                 return skb_get_hash_raw(skb) >> 1;
1842                         memset(&hash_keys, 0, sizeof(hash_keys));
1843                         skb_flow_dissect_flow_keys(skb, &keys, flag);
1844
1845                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1846                         hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1847                         hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1848                         hash_keys.ports.src = keys.ports.src;
1849                         hash_keys.ports.dst = keys.ports.dst;
1850                         hash_keys.basic.ip_proto = keys.basic.ip_proto;
1851                 } else {
1852                         memset(&hash_keys, 0, sizeof(hash_keys));
1853                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1854                         hash_keys.addrs.v4addrs.src = fl4->saddr;
1855                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
1856                         hash_keys.ports.src = fl4->fl4_sport;
1857                         hash_keys.ports.dst = fl4->fl4_dport;
1858                         hash_keys.basic.ip_proto = fl4->flowi4_proto;
1859                 }
1860                 break;
1861         }
1862         mhash = flow_hash_from_keys(&hash_keys);
1863
1864         return mhash >> 1;
1865 }
1866 EXPORT_SYMBOL_GPL(fib_multipath_hash);
1867 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1868
1869 static int ip_mkroute_input(struct sk_buff *skb,
1870                             struct fib_result *res,
1871                             struct in_device *in_dev,
1872                             __be32 daddr, __be32 saddr, u32 tos)
1873 {
1874 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1875         if (res->fi && res->fi->fib_nhs > 1) {
1876                 int h = fib_multipath_hash(res->fi, NULL, skb);
1877
1878                 fib_select_multipath(res, h);
1879         }
1880 #endif
1881
1882         /* create a routing cache entry */
1883         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1884 }
1885
1886 /*
1887  *      NOTE. We drop all the packets that has local source
1888  *      addresses, because every properly looped back packet
1889  *      must have correct destination already attached by output routine.
1890  *
1891  *      Such approach solves two big problems:
1892  *      1. Not simplex devices are handled properly.
1893  *      2. IP spoofing attempts are filtered with 100% of guarantee.
1894  *      called with rcu_read_lock()
1895  */
1896
1897 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1898                                u8 tos, struct net_device *dev,
1899                                struct fib_result *res)
1900 {
1901         struct in_device *in_dev = __in_dev_get_rcu(dev);
1902         struct ip_tunnel_info *tun_info;
1903         struct flowi4   fl4;
1904         unsigned int    flags = 0;
1905         u32             itag = 0;
1906         struct rtable   *rth;
1907         int             err = -EINVAL;
1908         struct net    *net = dev_net(dev);
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         err = fib_lookup(net, &fl4, res, 0);
1968         if (err != 0) {
1969                 if (!IN_DEV_FORWARD(in_dev))
1970                         err = -EHOSTUNREACH;
1971                 goto no_route;
1972         }
1973
1974         if (res->type == RTN_BROADCAST)
1975                 goto brd_input;
1976
1977         if (res->type == RTN_LOCAL) {
1978                 err = fib_validate_source(skb, saddr, daddr, tos,
1979                                           0, dev, in_dev, &itag);
1980                 if (err < 0)
1981                         goto martian_source;
1982                 goto local_input;
1983         }
1984
1985         if (!IN_DEV_FORWARD(in_dev)) {
1986                 err = -EHOSTUNREACH;
1987                 goto no_route;
1988         }
1989         if (res->type != RTN_UNICAST)
1990                 goto martian_destination;
1991
1992         err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1993 out:    return err;
1994
1995 brd_input:
1996         if (skb->protocol != htons(ETH_P_IP))
1997                 goto e_inval;
1998
1999         if (!ipv4_is_zeronet(saddr)) {
2000                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2001                                           in_dev, &itag);
2002                 if (err < 0)
2003                         goto martian_source;
2004         }
2005         flags |= RTCF_BROADCAST;
2006         res->type = RTN_BROADCAST;
2007         RT_CACHE_STAT_INC(in_brd);
2008
2009 local_input:
2010         do_cache = false;
2011         if (res->fi) {
2012                 if (!itag) {
2013                         rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2014                         if (rt_cache_valid(rth)) {
2015                                 skb_dst_set_noref(skb, &rth->dst);
2016                                 err = 0;
2017                                 goto out;
2018                         }
2019                         do_cache = true;
2020                 }
2021         }
2022
2023         rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2024                            flags | RTCF_LOCAL, res->type,
2025                            IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2026         if (!rth)
2027                 goto e_nobufs;
2028
2029         rth->dst.output= ip_rt_bug;
2030 #ifdef CONFIG_IP_ROUTE_CLASSID
2031         rth->dst.tclassid = itag;
2032 #endif
2033         rth->rt_is_input = 1;
2034         if (res->table)
2035                 rth->rt_table_id = res->table->tb_id;
2036
2037         RT_CACHE_STAT_INC(in_slow_tot);
2038         if (res->type == RTN_UNREACHABLE) {
2039                 rth->dst.input= ip_error;
2040                 rth->dst.error= -err;
2041                 rth->rt_flags   &= ~RTCF_LOCAL;
2042         }
2043
2044         if (do_cache) {
2045                 struct fib_nh *nh = &FIB_RES_NH(*res);
2046
2047                 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2048                 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2049                         WARN_ON(rth->dst.input == lwtunnel_input);
2050                         rth->dst.lwtstate->orig_input = rth->dst.input;
2051                         rth->dst.input = lwtunnel_input;
2052                 }
2053
2054                 if (unlikely(!rt_cache_route(nh, rth)))
2055                         rt_add_uncached_list(rth);
2056         }
2057         skb_dst_set(skb, &rth->dst);
2058         err = 0;
2059         goto out;
2060
2061 no_route:
2062         RT_CACHE_STAT_INC(in_no_route);
2063         res->type = RTN_UNREACHABLE;
2064         res->fi = NULL;
2065         res->table = NULL;
2066         goto local_input;
2067
2068         /*
2069          *      Do not cache martian addresses: they should be logged (RFC1812)
2070          */
2071 martian_destination:
2072         RT_CACHE_STAT_INC(in_martian_dst);
2073 #ifdef CONFIG_IP_ROUTE_VERBOSE
2074         if (IN_DEV_LOG_MARTIANS(in_dev))
2075                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2076                                      &daddr, &saddr, dev->name);
2077 #endif
2078
2079 e_inval:
2080         err = -EINVAL;
2081         goto out;
2082
2083 e_nobufs:
2084         err = -ENOBUFS;
2085         goto out;
2086
2087 martian_source:
2088         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2089         goto out;
2090 }
2091
2092 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2093                          u8 tos, struct net_device *dev)
2094 {
2095         struct fib_result res;
2096         int err;
2097
2098         tos &= IPTOS_RT_MASK;
2099         rcu_read_lock();
2100         err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2101         rcu_read_unlock();
2102
2103         return err;
2104 }
2105 EXPORT_SYMBOL(ip_route_input_noref);
2106
2107 /* called with rcu_read_lock held */
2108 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2109                        u8 tos, struct net_device *dev, struct fib_result *res)
2110 {
2111         /* Multicast recognition logic is moved from route cache to here.
2112            The problem was that too many Ethernet cards have broken/missing
2113            hardware multicast filters :-( As result the host on multicasting
2114            network acquires a lot of useless route cache entries, sort of
2115            SDR messages from all the world. Now we try to get rid of them.
2116            Really, provided software IP multicast filter is organized
2117            reasonably (at least, hashed), it does not result in a slowdown
2118            comparing with route cache reject entries.
2119            Note, that multicast routers are not affected, because
2120            route cache entry is created eventually.
2121          */
2122         if (ipv4_is_multicast(daddr)) {
2123                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2124                 int our = 0;
2125                 int err = -EINVAL;
2126
2127                 if (in_dev)
2128                         our = ip_check_mc_rcu(in_dev, daddr, saddr,
2129                                               ip_hdr(skb)->protocol);
2130
2131                 /* check l3 master if no match yet */
2132                 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2133                         struct in_device *l3_in_dev;
2134
2135                         l3_in_dev = __in_dev_get_rcu(skb->dev);
2136                         if (l3_in_dev)
2137                                 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2138                                                       ip_hdr(skb)->protocol);
2139                 }
2140
2141                 if (our
2142 #ifdef CONFIG_IP_MROUTE
2143                         ||
2144                     (!ipv4_is_local_multicast(daddr) &&
2145                      IN_DEV_MFORWARD(in_dev))
2146 #endif
2147                    ) {
2148                         err = ip_route_input_mc(skb, daddr, saddr,
2149                                                 tos, dev, our);
2150                 }
2151                 return err;
2152         }
2153
2154         return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2155 }
2156
2157 /* called with rcu_read_lock() */
2158 static struct rtable *__mkroute_output(const struct fib_result *res,
2159                                        const struct flowi4 *fl4, int orig_oif,
2160                                        struct net_device *dev_out,
2161                                        unsigned int flags)
2162 {
2163         struct fib_info *fi = res->fi;
2164         struct fib_nh_exception *fnhe;
2165         struct in_device *in_dev;
2166         u16 type = res->type;
2167         struct rtable *rth;
2168         bool do_cache;
2169
2170         in_dev = __in_dev_get_rcu(dev_out);
2171         if (!in_dev)
2172                 return ERR_PTR(-EINVAL);
2173
2174         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2175                 if (ipv4_is_loopback(fl4->saddr) &&
2176                     !(dev_out->flags & IFF_LOOPBACK) &&
2177                     !netif_is_l3_master(dev_out))
2178                         return ERR_PTR(-EINVAL);
2179
2180         if (ipv4_is_lbcast(fl4->daddr))
2181                 type = RTN_BROADCAST;
2182         else if (ipv4_is_multicast(fl4->daddr))
2183                 type = RTN_MULTICAST;
2184         else if (ipv4_is_zeronet(fl4->daddr))
2185                 return ERR_PTR(-EINVAL);
2186
2187         if (dev_out->flags & IFF_LOOPBACK)
2188                 flags |= RTCF_LOCAL;
2189
2190         do_cache = true;
2191         if (type == RTN_BROADCAST) {
2192                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2193                 fi = NULL;
2194         } else if (type == RTN_MULTICAST) {
2195                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2196                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2197                                      fl4->flowi4_proto))
2198                         flags &= ~RTCF_LOCAL;
2199                 else
2200                         do_cache = false;
2201                 /* If multicast route do not exist use
2202                  * default one, but do not gateway in this case.
2203                  * Yes, it is hack.
2204                  */
2205                 if (fi && res->prefixlen < 4)
2206                         fi = NULL;
2207         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2208                    (orig_oif != dev_out->ifindex)) {
2209                 /* For local routes that require a particular output interface
2210                  * we do not want to cache the result.  Caching the result
2211                  * causes incorrect behaviour when there are multiple source
2212                  * addresses on the interface, the end result being that if the
2213                  * intended recipient is waiting on that interface for the
2214                  * packet he won't receive it because it will be delivered on
2215                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2216                  * be set to the loopback interface as well.
2217                  */
2218                 fi = NULL;
2219         }
2220
2221         fnhe = NULL;
2222         do_cache &= fi != NULL;
2223         if (do_cache) {
2224                 struct rtable __rcu **prth;
2225                 struct fib_nh *nh = &FIB_RES_NH(*res);
2226
2227                 fnhe = find_exception(nh, fl4->daddr);
2228                 if (fnhe) {
2229                         prth = &fnhe->fnhe_rth_output;
2230                         rth = rcu_dereference(*prth);
2231                         if (rth && rth->dst.expires &&
2232                             time_after(jiffies, rth->dst.expires)) {
2233                                 ip_del_fnhe(nh, fl4->daddr);
2234                                 fnhe = NULL;
2235                         } else {
2236                                 goto rt_cache;
2237                         }
2238                 }
2239
2240                 if (unlikely(fl4->flowi4_flags &
2241                              FLOWI_FLAG_KNOWN_NH &&
2242                              !(nh->nh_gw &&
2243                                nh->nh_scope == RT_SCOPE_LINK))) {
2244                         do_cache = false;
2245                         goto add;
2246                 }
2247                 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2248                 rth = rcu_dereference(*prth);
2249
2250 rt_cache:
2251                 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2252                         return rth;
2253         }
2254
2255 add:
2256         rth = rt_dst_alloc(dev_out, flags, type,
2257                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
2258                            IN_DEV_CONF_GET(in_dev, NOXFRM),
2259                            do_cache);
2260         if (!rth)
2261                 return ERR_PTR(-ENOBUFS);
2262
2263         rth->rt_iif = orig_oif;
2264         if (res->table)
2265                 rth->rt_table_id = res->table->tb_id;
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         set_lwt_redirect(rth);
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         struct rtable *rth;
2302
2303         res.tclassid    = 0;
2304         res.fi          = NULL;
2305         res.table       = NULL;
2306
2307         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2308         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2309         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2310                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2311
2312         rcu_read_lock();
2313         rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2314         rcu_read_unlock();
2315
2316         return rth;
2317 }
2318 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2319
2320 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2321                                             struct fib_result *res,
2322                                             const struct sk_buff *skb)
2323 {
2324         struct net_device *dev_out = NULL;
2325         int orig_oif = fl4->flowi4_oif;
2326         unsigned int flags = 0;
2327         struct rtable *rth;
2328         int err = -ENETUNREACH;
2329
2330         if (fl4->saddr) {
2331                 rth = ERR_PTR(-EINVAL);
2332                 if (ipv4_is_multicast(fl4->saddr) ||
2333                     ipv4_is_lbcast(fl4->saddr) ||
2334                     ipv4_is_zeronet(fl4->saddr))
2335                         goto out;
2336
2337                 /* I removed check for oif == dev_out->oif here.
2338                    It was wrong for two reasons:
2339                    1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2340                       is assigned to multiple interfaces.
2341                    2. Moreover, we are allowed to send packets with saddr
2342                       of another iface. --ANK
2343                  */
2344
2345                 if (fl4->flowi4_oif == 0 &&
2346                     (ipv4_is_multicast(fl4->daddr) ||
2347                      ipv4_is_lbcast(fl4->daddr))) {
2348                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2349                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2350                         if (!dev_out)
2351                                 goto out;
2352
2353                         /* Special hack: user can direct multicasts
2354                            and limited broadcast via necessary interface
2355                            without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2356                            This hack is not just for fun, it allows
2357                            vic,vat and friends to work.
2358                            They bind socket to loopback, set ttl to zero
2359                            and expect that it will work.
2360                            From the viewpoint of routing cache they are broken,
2361                            because we are not allowed to build multicast path
2362                            with loopback source addr (look, routing cache
2363                            cannot know, that ttl is zero, so that packet
2364                            will not leave this host and route is valid).
2365                            Luckily, this hack is good workaround.
2366                          */
2367
2368                         fl4->flowi4_oif = dev_out->ifindex;
2369                         goto make_route;
2370                 }
2371
2372                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2373                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2374                         if (!__ip_dev_find(net, fl4->saddr, false))
2375                                 goto out;
2376                 }
2377         }
2378
2379
2380         if (fl4->flowi4_oif) {
2381                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2382                 rth = ERR_PTR(-ENODEV);
2383                 if (!dev_out)
2384                         goto out;
2385
2386                 /* RACE: Check return value of inet_select_addr instead. */
2387                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2388                         rth = ERR_PTR(-ENETUNREACH);
2389                         goto out;
2390                 }
2391                 if (ipv4_is_local_multicast(fl4->daddr) ||
2392                     ipv4_is_lbcast(fl4->daddr) ||
2393                     fl4->flowi4_proto == IPPROTO_IGMP) {
2394                         if (!fl4->saddr)
2395                                 fl4->saddr = inet_select_addr(dev_out, 0,
2396                                                               RT_SCOPE_LINK);
2397                         goto make_route;
2398                 }
2399                 if (!fl4->saddr) {
2400                         if (ipv4_is_multicast(fl4->daddr))
2401                                 fl4->saddr = inet_select_addr(dev_out, 0,
2402                                                               fl4->flowi4_scope);
2403                         else if (!fl4->daddr)
2404                                 fl4->saddr = inet_select_addr(dev_out, 0,
2405                                                               RT_SCOPE_HOST);
2406                 }
2407         }
2408
2409         if (!fl4->daddr) {
2410                 fl4->daddr = fl4->saddr;
2411                 if (!fl4->daddr)
2412                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2413                 dev_out = net->loopback_dev;
2414                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2415                 res->type = RTN_LOCAL;
2416                 flags |= RTCF_LOCAL;
2417                 goto make_route;
2418         }
2419
2420         err = fib_lookup(net, fl4, res, 0);
2421         if (err) {
2422                 res->fi = NULL;
2423                 res->table = NULL;
2424                 if (fl4->flowi4_oif &&
2425                     (ipv4_is_multicast(fl4->daddr) ||
2426                     !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2427                         /* Apparently, routing tables are wrong. Assume,
2428                            that the destination is on link.
2429
2430                            WHY? DW.
2431                            Because we are allowed to send to iface
2432                            even if it has NO routes and NO assigned
2433                            addresses. When oif is specified, routing
2434                            tables are looked up with only one purpose:
2435                            to catch if destination is gatewayed, rather than
2436                            direct. Moreover, if MSG_DONTROUTE is set,
2437                            we send packet, ignoring both routing tables
2438                            and ifaddr state. --ANK
2439
2440
2441                            We could make it even if oif is unknown,
2442                            likely IPv6, but we do not.
2443                          */
2444
2445                         if (fl4->saddr == 0)
2446                                 fl4->saddr = inet_select_addr(dev_out, 0,
2447                                                               RT_SCOPE_LINK);
2448                         res->type = RTN_UNICAST;
2449                         goto make_route;
2450                 }
2451                 rth = ERR_PTR(err);
2452                 goto out;
2453         }
2454
2455         if (res->type == RTN_LOCAL) {
2456                 if (!fl4->saddr) {
2457                         if (res->fi->fib_prefsrc)
2458                                 fl4->saddr = res->fi->fib_prefsrc;
2459                         else
2460                                 fl4->saddr = fl4->daddr;
2461                 }
2462
2463                 /* L3 master device is the loopback for that domain */
2464                 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2465                         net->loopback_dev;
2466
2467                 /* make sure orig_oif points to fib result device even
2468                  * though packet rx/tx happens over loopback or l3mdev
2469                  */
2470                 orig_oif = FIB_RES_OIF(*res);
2471
2472                 fl4->flowi4_oif = dev_out->ifindex;
2473                 flags |= RTCF_LOCAL;
2474                 goto make_route;
2475         }
2476
2477         fib_select_path(net, res, fl4, skb);
2478
2479         dev_out = FIB_RES_DEV(*res);
2480         fl4->flowi4_oif = dev_out->ifindex;
2481
2482
2483 make_route:
2484         rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2485
2486 out:
2487         return rth;
2488 }
2489
2490 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2491 {
2492         return NULL;
2493 }
2494
2495 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2496 {
2497         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2498
2499         return mtu ? : dst->dev->mtu;
2500 }
2501
2502 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2503                                           struct sk_buff *skb, u32 mtu)
2504 {
2505 }
2506
2507 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2508                                        struct sk_buff *skb)
2509 {
2510 }
2511
2512 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2513                                           unsigned long old)
2514 {
2515         return NULL;
2516 }
2517
2518 static struct dst_ops ipv4_dst_blackhole_ops = {
2519         .family                 =       AF_INET,
2520         .check                  =       ipv4_blackhole_dst_check,
2521         .mtu                    =       ipv4_blackhole_mtu,
2522         .default_advmss         =       ipv4_default_advmss,
2523         .update_pmtu            =       ipv4_rt_blackhole_update_pmtu,
2524         .redirect               =       ipv4_rt_blackhole_redirect,
2525         .cow_metrics            =       ipv4_rt_blackhole_cow_metrics,
2526         .neigh_lookup           =       ipv4_neigh_lookup,
2527 };
2528
2529 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2530 {
2531         struct rtable *ort = (struct rtable *) dst_orig;
2532         struct rtable *rt;
2533
2534         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2535         if (rt) {
2536                 struct dst_entry *new = &rt->dst;
2537
2538                 new->__use = 1;
2539                 new->input = dst_discard;
2540                 new->output = dst_discard_out;
2541
2542                 new->dev = net->loopback_dev;
2543                 if (new->dev)
2544                         dev_hold(new->dev);
2545
2546                 rt->rt_is_input = ort->rt_is_input;
2547                 rt->rt_iif = ort->rt_iif;
2548                 rt->rt_pmtu = ort->rt_pmtu;
2549
2550                 rt->rt_genid = rt_genid_ipv4(net);
2551                 rt->rt_flags = ort->rt_flags;
2552                 rt->rt_type = ort->rt_type;
2553                 rt->rt_gateway = ort->rt_gateway;
2554                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2555
2556                 INIT_LIST_HEAD(&rt->rt_uncached);
2557         }
2558
2559         dst_release(dst_orig);
2560
2561         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2562 }
2563
2564 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2565                                     const struct sock *sk)
2566 {
2567         struct rtable *rt = __ip_route_output_key(net, flp4);
2568
2569         if (IS_ERR(rt))
2570                 return rt;
2571
2572         if (flp4->flowi4_proto)
2573                 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2574                                                         flowi4_to_flowi(flp4),
2575                                                         sk, 0);
2576
2577         return rt;
2578 }
2579 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2580
2581 /* called with rcu_read_lock held */
2582 static int rt_fill_info(struct net *net,  __be32 dst, __be32 src, u32 table_id,
2583                         struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2584                         u32 seq)
2585 {
2586         struct rtable *rt = skb_rtable(skb);
2587         struct rtmsg *r;
2588         struct nlmsghdr *nlh;
2589         unsigned long expires = 0;
2590         u32 error;
2591         u32 metrics[RTAX_MAX];
2592
2593         nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2594         if (!nlh)
2595                 return -EMSGSIZE;
2596
2597         r = nlmsg_data(nlh);
2598         r->rtm_family    = AF_INET;
2599         r->rtm_dst_len  = 32;
2600         r->rtm_src_len  = 0;
2601         r->rtm_tos      = fl4->flowi4_tos;
2602         r->rtm_table    = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2603         if (nla_put_u32(skb, RTA_TABLE, table_id))
2604                 goto nla_put_failure;
2605         r->rtm_type     = rt->rt_type;
2606         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2607         r->rtm_protocol = RTPROT_UNSPEC;
2608         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2609         if (rt->rt_flags & RTCF_NOTIFY)
2610                 r->rtm_flags |= RTM_F_NOTIFY;
2611         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2612                 r->rtm_flags |= RTCF_DOREDIRECT;
2613
2614         if (nla_put_in_addr(skb, RTA_DST, dst))
2615                 goto nla_put_failure;
2616         if (src) {
2617                 r->rtm_src_len = 32;
2618                 if (nla_put_in_addr(skb, RTA_SRC, src))
2619                         goto nla_put_failure;
2620         }
2621         if (rt->dst.dev &&
2622             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2623                 goto nla_put_failure;
2624 #ifdef CONFIG_IP_ROUTE_CLASSID
2625         if (rt->dst.tclassid &&
2626             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2627                 goto nla_put_failure;
2628 #endif
2629         if (!rt_is_input_route(rt) &&
2630             fl4->saddr != src) {
2631                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2632                         goto nla_put_failure;
2633         }
2634         if (rt->rt_uses_gateway &&
2635             nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2636                 goto nla_put_failure;
2637
2638         expires = rt->dst.expires;
2639         if (expires) {
2640                 unsigned long now = jiffies;
2641
2642                 if (time_before(now, expires))
2643                         expires -= now;
2644                 else
2645                         expires = 0;
2646         }
2647
2648         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2649         if (rt->rt_pmtu && expires)
2650                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2651         if (rtnetlink_put_metrics(skb, metrics) < 0)
2652                 goto nla_put_failure;
2653
2654         if (fl4->flowi4_mark &&
2655             nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2656                 goto nla_put_failure;
2657
2658         if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2659             nla_put_u32(skb, RTA_UID,
2660                         from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2661                 goto nla_put_failure;
2662
2663         error = rt->dst.error;
2664
2665         if (rt_is_input_route(rt)) {
2666 #ifdef CONFIG_IP_MROUTE
2667                 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2668                     IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2669                         int err = ipmr_get_route(net, skb,
2670                                                  fl4->saddr, fl4->daddr,
2671                                                  r, portid);
2672
2673                         if (err <= 0) {
2674                                 if (err == 0)
2675                                         return 0;
2676                                 goto nla_put_failure;
2677                         }
2678                 } else
2679 #endif
2680                         if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2681                                 goto nla_put_failure;
2682         }
2683
2684         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2685                 goto nla_put_failure;
2686
2687         nlmsg_end(skb, nlh);
2688         return 0;
2689
2690 nla_put_failure:
2691         nlmsg_cancel(skb, nlh);
2692         return -EMSGSIZE;
2693 }
2694
2695 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2696                              struct netlink_ext_ack *extack)
2697 {
2698         struct net *net = sock_net(in_skb->sk);
2699         struct rtmsg *rtm;
2700         struct nlattr *tb[RTA_MAX+1];
2701         struct fib_result res = {};
2702         struct rtable *rt = NULL;
2703         struct flowi4 fl4;
2704         __be32 dst = 0;
2705         __be32 src = 0;
2706         u32 iif;
2707         int err;
2708         int mark;
2709         struct sk_buff *skb;
2710         u32 table_id = RT_TABLE_MAIN;
2711         kuid_t uid;
2712
2713         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2714                           extack);
2715         if (err < 0)
2716                 goto errout;
2717
2718         rtm = nlmsg_data(nlh);
2719
2720         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2721         if (!skb) {
2722                 err = -ENOBUFS;
2723                 goto errout;
2724         }
2725
2726         /* Reserve room for dummy headers, this skb can pass
2727            through good chunk of routing engine.
2728          */
2729         skb_reset_mac_header(skb);
2730         skb_reset_network_header(skb);
2731
2732         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2733         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2734         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2735         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2736         if (tb[RTA_UID])
2737                 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2738         else
2739                 uid = (iif ? INVALID_UID : current_uid());
2740
2741         /* Bugfix: need to give ip_route_input enough of an IP header to
2742          * not gag.
2743          */
2744         ip_hdr(skb)->protocol = IPPROTO_UDP;
2745         ip_hdr(skb)->saddr = src;
2746         ip_hdr(skb)->daddr = dst;
2747
2748         skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2749
2750         memset(&fl4, 0, sizeof(fl4));
2751         fl4.daddr = dst;
2752         fl4.saddr = src;
2753         fl4.flowi4_tos = rtm->rtm_tos;
2754         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2755         fl4.flowi4_mark = mark;
2756         fl4.flowi4_uid = uid;
2757
2758         rcu_read_lock();
2759
2760         if (iif) {
2761                 struct net_device *dev;
2762
2763                 dev = dev_get_by_index_rcu(net, iif);
2764                 if (!dev) {
2765                         err = -ENODEV;
2766                         goto errout_free;
2767                 }
2768
2769                 skb->protocol   = htons(ETH_P_IP);
2770                 skb->dev        = dev;
2771                 skb->mark       = mark;
2772                 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2773                                          dev, &res);
2774
2775                 rt = skb_rtable(skb);
2776                 if (err == 0 && rt->dst.error)
2777                         err = -rt->dst.error;
2778         } else {
2779                 fl4.flowi4_iif = LOOPBACK_IFINDEX;
2780                 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2781                 err = 0;
2782                 if (IS_ERR(rt))
2783                         err = PTR_ERR(rt);
2784                 else
2785                         skb_dst_set(skb, &rt->dst);
2786         }
2787
2788         if (err)
2789                 goto errout_free;
2790
2791         if (rtm->rtm_flags & RTM_F_NOTIFY)
2792                 rt->rt_flags |= RTCF_NOTIFY;
2793
2794         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2795                 table_id = rt->rt_table_id;
2796
2797         if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2798                 if (!res.fi) {
2799                         err = fib_props[res.type].error;
2800                         if (!err)
2801                                 err = -EHOSTUNREACH;
2802                         goto errout_free;
2803                 }
2804                 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2805                                     nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2806                                     rt->rt_type, res.prefix, res.prefixlen,
2807                                     fl4.flowi4_tos, res.fi, 0);
2808         } else {
2809                 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2810                                    NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2811         }
2812         if (err < 0)
2813                 goto errout_free;
2814
2815         rcu_read_unlock();
2816
2817         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2818 errout:
2819         return err;
2820
2821 errout_free:
2822         rcu_read_unlock();
2823         kfree_skb(skb);
2824         goto errout;
2825 }
2826
2827 void ip_rt_multicast_event(struct in_device *in_dev)
2828 {
2829         rt_cache_flush(dev_net(in_dev->dev));
2830 }
2831
2832 #ifdef CONFIG_SYSCTL
2833 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
2834 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
2835 static int ip_rt_gc_elasticity __read_mostly    = 8;
2836 static int ip_min_valid_pmtu __read_mostly      = IPV4_MIN_MTU;
2837
2838 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2839                                         void __user *buffer,
2840                                         size_t *lenp, loff_t *ppos)
2841 {
2842         struct net *net = (struct net *)__ctl->extra1;
2843
2844         if (write) {
2845                 rt_cache_flush(net);
2846                 fnhe_genid_bump(net);
2847                 return 0;
2848         }
2849
2850         return -EINVAL;
2851 }
2852
2853 static struct ctl_table ipv4_route_table[] = {
2854         {
2855                 .procname       = "gc_thresh",
2856                 .data           = &ipv4_dst_ops.gc_thresh,
2857                 .maxlen         = sizeof(int),
2858                 .mode           = 0644,
2859                 .proc_handler   = proc_dointvec,
2860         },
2861         {
2862                 .procname       = "max_size",
2863                 .data           = &ip_rt_max_size,
2864                 .maxlen         = sizeof(int),
2865                 .mode           = 0644,
2866                 .proc_handler   = proc_dointvec,
2867         },
2868         {
2869                 /*  Deprecated. Use gc_min_interval_ms */
2870
2871                 .procname       = "gc_min_interval",
2872                 .data           = &ip_rt_gc_min_interval,
2873                 .maxlen         = sizeof(int),
2874                 .mode           = 0644,
2875                 .proc_handler   = proc_dointvec_jiffies,
2876         },
2877         {
2878                 .procname       = "gc_min_interval_ms",
2879                 .data           = &ip_rt_gc_min_interval,
2880                 .maxlen         = sizeof(int),
2881                 .mode           = 0644,
2882                 .proc_handler   = proc_dointvec_ms_jiffies,
2883         },
2884         {
2885                 .procname       = "gc_timeout",
2886                 .data           = &ip_rt_gc_timeout,
2887                 .maxlen         = sizeof(int),
2888                 .mode           = 0644,
2889                 .proc_handler   = proc_dointvec_jiffies,
2890         },
2891         {
2892                 .procname       = "gc_interval",
2893                 .data           = &ip_rt_gc_interval,
2894                 .maxlen         = sizeof(int),
2895                 .mode           = 0644,
2896                 .proc_handler   = proc_dointvec_jiffies,
2897         },
2898         {
2899                 .procname       = "redirect_load",
2900                 .data           = &ip_rt_redirect_load,
2901                 .maxlen         = sizeof(int),
2902                 .mode           = 0644,
2903                 .proc_handler   = proc_dointvec,
2904         },
2905         {
2906                 .procname       = "redirect_number",
2907                 .data           = &ip_rt_redirect_number,
2908                 .maxlen         = sizeof(int),
2909                 .mode           = 0644,
2910                 .proc_handler   = proc_dointvec,
2911         },
2912         {
2913                 .procname       = "redirect_silence",
2914                 .data           = &ip_rt_redirect_silence,
2915                 .maxlen         = sizeof(int),
2916                 .mode           = 0644,
2917                 .proc_handler   = proc_dointvec,
2918         },
2919         {
2920                 .procname       = "error_cost",
2921                 .data           = &ip_rt_error_cost,
2922                 .maxlen         = sizeof(int),
2923                 .mode           = 0644,
2924                 .proc_handler   = proc_dointvec,
2925         },
2926         {
2927                 .procname       = "error_burst",
2928                 .data           = &ip_rt_error_burst,
2929                 .maxlen         = sizeof(int),
2930                 .mode           = 0644,
2931                 .proc_handler   = proc_dointvec,
2932         },
2933         {
2934                 .procname       = "gc_elasticity",
2935                 .data           = &ip_rt_gc_elasticity,
2936                 .maxlen         = sizeof(int),
2937                 .mode           = 0644,
2938                 .proc_handler   = proc_dointvec,
2939         },
2940         {
2941                 .procname       = "mtu_expires",
2942                 .data           = &ip_rt_mtu_expires,
2943                 .maxlen         = sizeof(int),
2944                 .mode           = 0644,
2945                 .proc_handler   = proc_dointvec_jiffies,
2946         },
2947         {
2948                 .procname       = "min_pmtu",
2949                 .data           = &ip_rt_min_pmtu,
2950                 .maxlen         = sizeof(int),
2951                 .mode           = 0644,
2952                 .proc_handler   = proc_dointvec_minmax,
2953                 .extra1         = &ip_min_valid_pmtu,
2954         },
2955         {
2956                 .procname       = "min_adv_mss",
2957                 .data           = &ip_rt_min_advmss,
2958                 .maxlen         = sizeof(int),
2959                 .mode           = 0644,
2960                 .proc_handler   = proc_dointvec,
2961         },
2962         { }
2963 };
2964
2965 static struct ctl_table ipv4_route_flush_table[] = {
2966         {
2967                 .procname       = "flush",
2968                 .maxlen         = sizeof(int),
2969                 .mode           = 0200,
2970                 .proc_handler   = ipv4_sysctl_rtcache_flush,
2971         },
2972         { },
2973 };
2974
2975 static __net_init int sysctl_route_net_init(struct net *net)
2976 {
2977         struct ctl_table *tbl;
2978
2979         tbl = ipv4_route_flush_table;
2980         if (!net_eq(net, &init_net)) {
2981                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2982                 if (!tbl)
2983                         goto err_dup;
2984
2985                 /* Don't export sysctls to unprivileged users */
2986                 if (net->user_ns != &init_user_ns)
2987                         tbl[0].procname = NULL;
2988         }
2989         tbl[0].extra1 = net;
2990
2991         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2992         if (!net->ipv4.route_hdr)
2993                 goto err_reg;
2994         return 0;
2995
2996 err_reg:
2997         if (tbl != ipv4_route_flush_table)
2998                 kfree(tbl);
2999 err_dup:
3000         return -ENOMEM;
3001 }
3002
3003 static __net_exit void sysctl_route_net_exit(struct net *net)
3004 {
3005         struct ctl_table *tbl;
3006
3007         tbl = net->ipv4.route_hdr->ctl_table_arg;
3008         unregister_net_sysctl_table(net->ipv4.route_hdr);
3009         BUG_ON(tbl == ipv4_route_flush_table);
3010         kfree(tbl);
3011 }
3012
3013 static __net_initdata struct pernet_operations sysctl_route_ops = {
3014         .init = sysctl_route_net_init,
3015         .exit = sysctl_route_net_exit,
3016 };
3017 #endif
3018
3019 static __net_init int rt_genid_init(struct net *net)
3020 {
3021         atomic_set(&net->ipv4.rt_genid, 0);
3022         atomic_set(&net->fnhe_genid, 0);
3023         atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3024         return 0;
3025 }
3026
3027 static __net_initdata struct pernet_operations rt_genid_ops = {
3028         .init = rt_genid_init,
3029 };
3030
3031 static int __net_init ipv4_inetpeer_init(struct net *net)
3032 {
3033         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3034
3035         if (!bp)
3036                 return -ENOMEM;
3037         inet_peer_base_init(bp);
3038         net->ipv4.peers = bp;
3039         return 0;
3040 }
3041
3042 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3043 {
3044         struct inet_peer_base *bp = net->ipv4.peers;
3045
3046         net->ipv4.peers = NULL;
3047         inetpeer_invalidate_tree(bp);
3048         kfree(bp);
3049 }
3050
3051 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3052         .init   =       ipv4_inetpeer_init,
3053         .exit   =       ipv4_inetpeer_exit,
3054 };
3055
3056 #ifdef CONFIG_IP_ROUTE_CLASSID
3057 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3058 #endif /* CONFIG_IP_ROUTE_CLASSID */
3059
3060 int __init ip_rt_init(void)
3061 {
3062         int cpu;
3063
3064         ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3065         if (!ip_idents)
3066                 panic("IP: failed to allocate ip_idents\n");
3067
3068         prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3069
3070         ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3071         if (!ip_tstamps)
3072                 panic("IP: failed to allocate ip_tstamps\n");
3073
3074         for_each_possible_cpu(cpu) {
3075                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3076
3077                 INIT_LIST_HEAD(&ul->head);
3078                 spin_lock_init(&ul->lock);
3079         }
3080 #ifdef CONFIG_IP_ROUTE_CLASSID
3081         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3082         if (!ip_rt_acct)
3083                 panic("IP: failed to allocate ip_rt_acct\n");
3084 #endif
3085
3086         ipv4_dst_ops.kmem_cachep =
3087                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3088                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3089
3090         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3091
3092         if (dst_entries_init(&ipv4_dst_ops) < 0)
3093                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3094
3095         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3096                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3097
3098         ipv4_dst_ops.gc_thresh = ~0;
3099         ip_rt_max_size = INT_MAX;
3100
3101         devinet_init();
3102         ip_fib_init();
3103
3104         if (ip_rt_proc_init())
3105                 pr_err("Unable to create route proc files\n");
3106 #ifdef CONFIG_XFRM
3107         xfrm_init();
3108         xfrm4_init();
3109 #endif
3110         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3111                       RTNL_FLAG_DOIT_UNLOCKED);
3112
3113 #ifdef CONFIG_SYSCTL
3114         register_pernet_subsys(&sysctl_route_ops);
3115 #endif
3116         register_pernet_subsys(&rt_genid_ops);
3117         register_pernet_subsys(&ipv4_inetpeer_ops);
3118         return 0;
3119 }
3120
3121 #ifdef CONFIG_SYSCTL
3122 /*
3123  * We really need to sanitize the damn ipv4 init order, then all
3124  * this nonsense will go away.
3125  */
3126 void __init ip_static_sysctl_init(void)
3127 {
3128         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3129 }
3130 #endif