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