net/ipv4/route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              ROUTE - implementation of the IP router.
   8  *
   9  * Authors:     Ross Biro
  10  *              Fred N. van Kempen, <[email protected]>
  11  *              Alan Cox, <[email protected]>
  12  *              Linus Torvalds, <[email protected]>
  13  *              Alexey Kuznetsov, <[email protected]>
  14  *
  15  * Fixes:
  16  *              Alan Cox        :       Verify area fixes.
  17  *              Alan Cox        :       cli() protects routing changes
  18  *              Rui Oliveira    :       ICMP routing table updates
  19  *              ([email protected])      Routing table insertion and update
  20  *              Linus Torvalds  :       Rewrote bits to be sensible
  21  *              Alan Cox        :       Added BSD route gw semantics
  22  *              Alan Cox        :       Super /proc >4K
  23  *              Alan Cox        :       MTU in route table
  24  *              Alan Cox        :       MSS actually. Also added the window
  25  *                                      clamper.
  26  *              Sam Lantinga    :       Fixed route matching in rt_del()
  27  *              Alan Cox        :       Routing cache support.
  28  *              Alan Cox        :       Removed compatibility cruft.
  29  *              Alan Cox        :       RTF_REJECT support.
  30  *              Alan Cox        :       TCP irtt support.
  31  *              Jonathan Naylor :       Added Metric support.
  32  *      Miquel van Smoorenburg  :       BSD API fixes.
  33  *      Miquel van Smoorenburg  :       Metrics.
  34  *              Alan Cox        :       Use __u32 properly
  35  *              Alan Cox        :       Aligned routing errors more closely with BSD
  36  *                                      our system is still very different.
  37  *              Alan Cox        :       Faster /proc handling
  38  *      Alexey Kuznetsov        :       Massive rework to support tree based routing,
  39  *                                      routing caches and better behaviour.
  40  *
  41  *              Olaf Erb        :       irtt wasn't being copied right.
  42  *              Bjorn Ekwall    :       Kerneld route support.
  43  *              Alan Cox        :       Multicast fixed (I hope)
  44  *              Pavel Krauz     :       Limited broadcast fixed
  45  *              Mike McLagan    :       Routing by source
  46  *      Alexey Kuznetsov        :       End of old history. Split to fib.c and
  47  *                                      route.c and rewritten from scratch.
  48  *              Andi Kleen      :       Load-limit warning messages.
  49  *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
  50  *      Vitaly E. Lavrov        :       Race condition in ip_route_input_slow.
  51  *      Tobias Ringstrom        :       Uninitialized res.type in ip_route_output_slow.
  52  *      Vladimir V. Ivanov      :       IP rule info (flowid) is really useful.
  53  *              Marc Boucher    :       routing by fwmark
  54  *      Robert Olsson           :       Added rt_cache statistics
  55  *      Arnaldo C. Melo         :       Convert proc stuff to seq_file
  56  *      Eric Dumazet            :       hashed spinlocks and rt_check_expire() fixes.
  57  *      Ilia Sotnikov           :       Ignore TOS on PMTUD and Redirect
  58  *      Ilia Sotnikov           :       Removed TOS from hash calculations
  59  */
  60
  61 #define pr_fmt(fmt) "IPv4: " fmt
  62
  63 #include <linux/module.h>
  64 #include <linux/uaccess.h>
  65 #include <linux/bitops.h>
  66 #include <linux/types.h>
  67 #include <linux/kernel.h>
  68 #include <linux/mm.h>
  69 #include <linux/memblock.h>
  70 #include <linux/string.h>
  71 #include <linux/socket.h>
  72 #include <linux/sockios.h>
  73 #include <linux/errno.h>
  74 #include <linux/in.h>
  75 #include <linux/inet.h>
  76 #include <linux/netdevice.h>
  77 #include <linux/proc_fs.h>
  78 #include <linux/init.h>
  79 #include <linux/skbuff.h>
  80 #include <linux/inetdevice.h>
  81 #include <linux/igmp.h>
  82 #include <linux/pkt_sched.h>
  83 #include <linux/mroute.h>
  84 #include <linux/netfilter_ipv4.h>
  85 #include <linux/random.h>
  86 #include <linux/rcupdate.h>
  87 #include <linux/times.h>
  88 #include <linux/slab.h>
  89 #include <linux/jhash.h>
  90 #include <net/dst.h>
  91 #include <net/dst_metadata.h>
  92 #include <net/net_namespace.h>
  93 #include <net/protocol.h>
  94 #include <net/ip.h>
  95 #include <net/route.h>
  96 #include <net/inetpeer.h>
  97 #include <net/sock.h>
  98 #include <net/ip_fib.h>
  99 #include <net/nexthop.h>
 100 #include <net/arp.h>
 101 #include <net/tcp.h>
 102 #include <net/icmp.h>
 103 #include <net/xfrm.h>
 104 #include <net/lwtunnel.h>
 105 #include <net/netevent.h>
 106 #include <net/rtnetlink.h>
 107 #ifdef CONFIG_SYSCTL
 108 #include <linux/sysctl.h>
 109 #endif
 110 #include <net/secure_seq.h>
 111 #include <net/ip_tunnels.h>
 112 #include <net/l3mdev.h>
 113
 114 #include "fib_lookup.h"
 115
 116 #define RT_FL_TOS(oldflp4) \
 117         ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
 118
 119 #define RT_GC_TIMEOUT (300*HZ)
 120
 121 static int ip_rt_max_size;
 122 static int ip_rt_redirect_number __read_mostly  = 9;
 123 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 125 static int ip_rt_error_cost __read_mostly       = HZ;
 126 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 127 static int ip_rt_mtu_expires __read_mostly      = 10 * 60 * HZ;
 128 static u32 ip_rt_min_pmtu __read_mostly         = 512 + 20 + 20;
 129 static int ip_rt_min_advmss __read_mostly       = 256;
 130
 131 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 132
 133 /*
 134  *      Interface to generic destination cache.
 135  */
 136
 137 INDIRECT_CALLABLE_SCOPE
 138 struct dst_entry        *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 139 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 140 INDIRECT_CALLABLE_SCOPE
 141 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                                            bool confirm_neigh);
 147 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
 148                                         struct sk_buff *skb);
 149 static void             ipv4_dst_destroy(struct dst_entry *dst);
 150
 151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 152 {
 153         WARN_ON(1);
 154         return NULL;
 155 }
 156
 157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 158                                            struct sk_buff *skb,
 159                                            const void *daddr);
 160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
 161
 162 static struct dst_ops ipv4_dst_ops = {
 163         .family =               AF_INET,
 164         .check =                ipv4_dst_check,
 165         .default_advmss =       ipv4_default_advmss,
 166         .mtu =                  ipv4_mtu,
 167         .cow_metrics =          ipv4_cow_metrics,
 168         .destroy =              ipv4_dst_destroy,
 169         .negative_advice =      ipv4_negative_advice,
 170         .link_failure =         ipv4_link_failure,
 171         .update_pmtu =          ip_rt_update_pmtu,
 172         .redirect =             ip_do_redirect,
 173         .local_out =            __ip_local_out,
 174         .neigh_lookup =         ipv4_neigh_lookup,
 175         .confirm_neigh =        ipv4_confirm_neigh,
 176 };
 177
 178 #define ECN_OR_COST(class)      TC_PRIO_##class
 179
 180 const __u8 ip_tos2prio[16] = {
 181         TC_PRIO_BESTEFFORT,
 182         ECN_OR_COST(BESTEFFORT),
 183         TC_PRIO_BESTEFFORT,
 184         ECN_OR_COST(BESTEFFORT),
 185         TC_PRIO_BULK,
 186         ECN_OR_COST(BULK),
 187         TC_PRIO_BULK,
 188         ECN_OR_COST(BULK),
 189         TC_PRIO_INTERACTIVE,
 190         ECN_OR_COST(INTERACTIVE),
 191         TC_PRIO_INTERACTIVE,
 192         ECN_OR_COST(INTERACTIVE),
 193         TC_PRIO_INTERACTIVE_BULK,
 194         ECN_OR_COST(INTERACTIVE_BULK),
 195         TC_PRIO_INTERACTIVE_BULK,
 196         ECN_OR_COST(INTERACTIVE_BULK)
 197 };
 198 EXPORT_SYMBOL(ip_tos2prio);
 199
 200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
 202
 203 #ifdef CONFIG_PROC_FS
 204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 205 {
 206         if (*pos)
 207                 return NULL;
 208         return SEQ_START_TOKEN;
 209 }
 210
 211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 212 {
 213         ++*pos;
 214         return NULL;
 215 }
 216
 217 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 218 {
 219 }
 220
 221 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 222 {
 223         if (v == SEQ_START_TOKEN)
 224                 seq_printf(seq, "%-127s\n",
 225                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 226                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 227                            "HHUptod\tSpecDst");
 228         return 0;
 229 }
 230
 231 static const struct seq_operations rt_cache_seq_ops = {
 232         .start  = rt_cache_seq_start,
 233         .next   = rt_cache_seq_next,
 234         .stop   = rt_cache_seq_stop,
 235         .show   = rt_cache_seq_show,
 236 };
 237
 238 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 239 {
 240         int cpu;
 241
 242         if (*pos == 0)
 243                 return SEQ_START_TOKEN;
 244
 245         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 246                 if (!cpu_possible(cpu))
 247                         continue;
 248                 *pos = cpu+1;
 249                 return &per_cpu(rt_cache_stat, cpu);
 250         }
 251         return NULL;
 252 }
 253
 254 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 255 {
 256         int cpu;
 257
 258         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 259                 if (!cpu_possible(cpu))
 260                         continue;
 261                 *pos = cpu+1;
 262                 return &per_cpu(rt_cache_stat, cpu);
 263         }
 264         (*pos)++;
 265         return NULL;
 266
 267 }
 268
 269 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 270 {
 271
 272 }
 273
 274 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 275 {
 276         struct rt_cache_stat *st = v;
 277
 278         if (v == SEQ_START_TOKEN) {
 279                 seq_puts(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");
 280                 return 0;
 281         }
 282
 283         seq_printf(seq, "%08x %08x %08x    %08x   %08x    %08x %08x       "
 284                         "%08x       %08x %08x     %08x    %08x %08x   "
 285                         "%08x     %08x        %08x        %08x\n",
 286                    dst_entries_get_slow(&ipv4_dst_ops),
 287                    0, /* st->in_hit */
 288                    st->in_slow_tot,
 289                    st->in_slow_mc,
 290                    st->in_no_route,
 291                    st->in_brd,
 292                    st->in_martian_dst,
 293                    st->in_martian_src,
 294
 295                    0, /* st->out_hit */
 296                    st->out_slow_tot,
 297                    st->out_slow_mc,
 298
 299                    0, /* st->gc_total */
 300                    0, /* st->gc_ignored */
 301                    0, /* st->gc_goal_miss */
 302                    0, /* st->gc_dst_overflow */
 303                    0, /* st->in_hlist_search */
 304                    0  /* st->out_hlist_search */
 305                 );
 306         return 0;
 307 }
 308
 309 static const struct seq_operations rt_cpu_seq_ops = {
 310         .start  = rt_cpu_seq_start,
 311         .next   = rt_cpu_seq_next,
 312         .stop   = rt_cpu_seq_stop,
 313         .show   = rt_cpu_seq_show,
 314 };
 315
 316 #ifdef CONFIG_IP_ROUTE_CLASSID
 317 static int rt_acct_proc_show(struct seq_file *m, void *v)
 318 {
 319         struct ip_rt_acct *dst, *src;
 320         unsigned int i, j;
 321
 322         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 323         if (!dst)
 324                 return -ENOMEM;
 325
 326         for_each_possible_cpu(i) {
 327                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 328                 for (j = 0; j < 256; j++) {
 329                         dst[j].o_bytes   += src[j].o_bytes;
 330                         dst[j].o_packets += src[j].o_packets;
 331                         dst[j].i_bytes   += src[j].i_bytes;
 332                         dst[j].i_packets += src[j].i_packets;
 333                 }
 334         }
 335
 336         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 337         kfree(dst);
 338         return 0;
 339 }
 340 #endif
 341
 342 static int __net_init ip_rt_do_proc_init(struct net *net)
 343 {
 344         struct proc_dir_entry *pde;
 345
 346         pde = proc_create_seq("rt_cache", 0444, net->proc_net,
 347                               &rt_cache_seq_ops);
 348         if (!pde)
 349                 goto err1;
 350
 351         pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
 352                               &rt_cpu_seq_ops);
 353         if (!pde)
 354                 goto err2;
 355
 356 #ifdef CONFIG_IP_ROUTE_CLASSID
 357         pde = proc_create_single("rt_acct", 0, net->proc_net,
 358                         rt_acct_proc_show);
 359         if (!pde)
 360                 goto err3;
 361 #endif
 362         return 0;
 363
 364 #ifdef CONFIG_IP_ROUTE_CLASSID
 365 err3:
 366         remove_proc_entry("rt_cache", net->proc_net_stat);
 367 #endif
 368 err2:
 369         remove_proc_entry("rt_cache", net->proc_net);
 370 err1:
 371         return -ENOMEM;
 372 }
 373
 374 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 375 {
 376         remove_proc_entry("rt_cache", net->proc_net_stat);
 377         remove_proc_entry("rt_cache", net->proc_net);
 378 #ifdef CONFIG_IP_ROUTE_CLASSID
 379         remove_proc_entry("rt_acct", net->proc_net);
 380 #endif
 381 }
 382
 383 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 384         .init = ip_rt_do_proc_init,
 385         .exit = ip_rt_do_proc_exit,
 386 };
 387
 388 static int __init ip_rt_proc_init(void)
 389 {
 390         return register_pernet_subsys(&ip_rt_proc_ops);
 391 }
 392
 393 #else
 394 static inline int ip_rt_proc_init(void)
 395 {
 396         return 0;
 397 }
 398 #endif /* CONFIG_PROC_FS */
 399
 400 static inline bool rt_is_expired(const struct rtable *rth)
 401 {
 402         return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
 403 }
 404
 405 void rt_cache_flush(struct net *net)
 406 {
 407         rt_genid_bump_ipv4(net);
 408 }
 409
 410 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 411                                            struct sk_buff *skb,
 412                                            const void *daddr)
 413 {
 414         const struct rtable *rt = container_of(dst, struct rtable, dst);
 415         struct net_device *dev = dst->dev;
 416         struct neighbour *n;
 417
 418         rcu_read_lock_bh();
 419
 420         if (likely(rt->rt_gw_family == AF_INET)) {
 421                 n = ip_neigh_gw4(dev, rt->rt_gw4);
 422         } else if (rt->rt_gw_family == AF_INET6) {
 423                 n = ip_neigh_gw6(dev, &rt->rt_gw6);
 424         } else {
 425                 __be32 pkey;
 426
 427                 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
 428                 n = ip_neigh_gw4(dev, pkey);
 429         }
 430
 431         if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
 432                 n = NULL;
 433
 434         rcu_read_unlock_bh();
 435
 436         return n;
 437 }
 438
 439 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 440 {
 441         const struct rtable *rt = container_of(dst, struct rtable, dst);
 442         struct net_device *dev = dst->dev;
 443         const __be32 *pkey = daddr;
 444
 445         if (rt->rt_gw_family == AF_INET) {
 446                 pkey = (const __be32 *)&rt->rt_gw4;
 447         } else if (rt->rt_gw_family == AF_INET6) {
 448                 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
 449         } else if (!daddr ||
 450                  (rt->rt_flags &
 451                   (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
 452                 return;
 453         }
 454         __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
 455 }
 456
 457 /* Hash tables of size 2048..262144 depending on RAM size.
 458  * Each bucket uses 8 bytes.
 459  */
 460 static u32 ip_idents_mask __read_mostly;
 461 static atomic_t *ip_idents __read_mostly;
 462 static u32 *ip_tstamps __read_mostly;
 463
 464 /* In order to protect privacy, we add a perturbation to identifiers
 465  * if one generator is seldom used. This makes hard for an attacker
 466  * to infer how many packets were sent between two points in time.
 467  */
 468 u32 ip_idents_reserve(u32 hash, int segs)
 469 {
 470         u32 bucket, old, now = (u32)jiffies;
 471         atomic_t *p_id;
 472         u32 *p_tstamp;
 473         u32 delta = 0;
 474
 475         bucket = hash & ip_idents_mask;
 476         p_tstamp = ip_tstamps + bucket;
 477         p_id = ip_idents + bucket;
 478         old = READ_ONCE(*p_tstamp);
 479
 480         if (old != now && cmpxchg(p_tstamp, old, now) == old)
 481                 delta = prandom_u32_max(now - old);
 482
 483         /* If UBSAN reports an error there, please make sure your compiler
 484          * supports -fno-strict-overflow before reporting it that was a bug
 485          * in UBSAN, and it has been fixed in GCC-8.
 486          */
 487         return atomic_add_return(segs + delta, p_id) - segs;
 488 }
 489 EXPORT_SYMBOL(ip_idents_reserve);
 490
 491 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
 492 {
 493         u32 hash, id;
 494
 495         /* Note the following code is not safe, but this is okay. */
 496         if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
 497                 get_random_bytes(&net->ipv4.ip_id_key,
 498                                  sizeof(net->ipv4.ip_id_key));
 499
 500         hash = siphash_3u32((__force u32)iph->daddr,
 501                             (__force u32)iph->saddr,
 502                             iph->protocol,
 503                             &net->ipv4.ip_id_key);
 504         id = ip_idents_reserve(hash, segs);
 505         iph->id = htons(id);
 506 }
 507 EXPORT_SYMBOL(__ip_select_ident);
 508
 509 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
 510                              const struct sock *sk,
 511                              const struct iphdr *iph,
 512                              int oif, u8 tos,
 513                              u8 prot, u32 mark, int flow_flags)
 514 {
 515         if (sk) {
 516                 const struct inet_sock *inet = inet_sk(sk);
 517
 518                 oif = sk->sk_bound_dev_if;
 519                 mark = sk->sk_mark;
 520                 tos = RT_CONN_FLAGS(sk);
 521                 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
 522         }
 523         flowi4_init_output(fl4, oif, mark, tos,
 524                            RT_SCOPE_UNIVERSE, prot,
 525                            flow_flags,
 526                            iph->daddr, iph->saddr, 0, 0,
 527                            sock_net_uid(net, sk));
 528 }
 529
 530 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
 531                                const struct sock *sk)
 532 {
 533         const struct net *net = dev_net(skb->dev);
 534         const struct iphdr *iph = ip_hdr(skb);
 535         int oif = skb->dev->ifindex;
 536         u8 tos = RT_TOS(iph->tos);
 537         u8 prot = iph->protocol;
 538         u32 mark = skb->mark;
 539
 540         __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
 541 }
 542
 543 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
 544 {
 545         const struct inet_sock *inet = inet_sk(sk);
 546         const struct ip_options_rcu *inet_opt;
 547         __be32 daddr = inet->inet_daddr;
 548
 549         rcu_read_lock();
 550         inet_opt = rcu_dereference(inet->inet_opt);
 551         if (inet_opt && inet_opt->opt.srr)
 552                 daddr = inet_opt->opt.faddr;
 553         flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
 554                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
 555                            inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
 556                            inet_sk_flowi_flags(sk),
 557                            daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
 558         rcu_read_unlock();
 559 }
 560
 561 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
 562                                  const struct sk_buff *skb)
 563 {
 564         if (skb)
 565                 build_skb_flow_key(fl4, skb, sk);
 566         else
 567                 build_sk_flow_key(fl4, sk);
 568 }
 569
 570 static DEFINE_SPINLOCK(fnhe_lock);
 571
 572 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
 573 {
 574         struct rtable *rt;
 575
 576         rt = rcu_dereference(fnhe->fnhe_rth_input);
 577         if (rt) {
 578                 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
 579                 dst_dev_put(&rt->dst);
 580                 dst_release(&rt->dst);
 581         }
 582         rt = rcu_dereference(fnhe->fnhe_rth_output);
 583         if (rt) {
 584                 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
 585                 dst_dev_put(&rt->dst);
 586                 dst_release(&rt->dst);
 587         }
 588 }
 589
 590 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
 591 {
 592         struct fib_nh_exception *fnhe, *oldest;
 593
 594         oldest = rcu_dereference(hash->chain);
 595         for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
 596              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 597                 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
 598                         oldest = fnhe;
 599         }
 600         fnhe_flush_routes(oldest);
 601         return oldest;
 602 }
 603
 604 static inline u32 fnhe_hashfun(__be32 daddr)
 605 {
 606         static u32 fnhe_hashrnd __read_mostly;
 607         u32 hval;
 608
 609         net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
 610         hval = jhash_1word((__force u32)daddr, fnhe_hashrnd);
 611         return hash_32(hval, FNHE_HASH_SHIFT);
 612 }
 613
 614 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
 615 {
 616         rt->rt_pmtu = fnhe->fnhe_pmtu;
 617         rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
 618         rt->dst.expires = fnhe->fnhe_expires;
 619
 620         if (fnhe->fnhe_gw) {
 621                 rt->rt_flags |= RTCF_REDIRECTED;
 622                 rt->rt_uses_gateway = 1;
 623                 rt->rt_gw_family = AF_INET;
 624                 rt->rt_gw4 = fnhe->fnhe_gw;
 625         }
 626 }
 627
 628 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
 629                                   __be32 gw, u32 pmtu, bool lock,
 630                                   unsigned long expires)
 631 {
 632         struct fnhe_hash_bucket *hash;
 633         struct fib_nh_exception *fnhe;
 634         struct rtable *rt;
 635         u32 genid, hval;
 636         unsigned int i;
 637         int depth;
 638
 639         genid = fnhe_genid(dev_net(nhc->nhc_dev));
 640         hval = fnhe_hashfun(daddr);
 641
 642         spin_lock_bh(&fnhe_lock);
 643
 644         hash = rcu_dereference(nhc->nhc_exceptions);
 645         if (!hash) {
 646                 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
 647                 if (!hash)
 648                         goto out_unlock;
 649                 rcu_assign_pointer(nhc->nhc_exceptions, hash);
 650         }
 651
 652         hash += hval;
 653
 654         depth = 0;
 655         for (fnhe = rcu_dereference(hash->chain); fnhe;
 656              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 657                 if (fnhe->fnhe_daddr == daddr)
 658                         break;
 659                 depth++;
 660         }
 661
 662         if (fnhe) {
 663                 if (fnhe->fnhe_genid != genid)
 664                         fnhe->fnhe_genid = genid;
 665                 if (gw)
 666                         fnhe->fnhe_gw = gw;
 667                 if (pmtu) {
 668                         fnhe->fnhe_pmtu = pmtu;
 669                         fnhe->fnhe_mtu_locked = lock;
 670                 }
 671                 fnhe->fnhe_expires = max(1UL, expires);
 672                 /* Update all cached dsts too */
 673                 rt = rcu_dereference(fnhe->fnhe_rth_input);
 674                 if (rt)
 675                         fill_route_from_fnhe(rt, fnhe);
 676                 rt = rcu_dereference(fnhe->fnhe_rth_output);
 677                 if (rt)
 678                         fill_route_from_fnhe(rt, fnhe);
 679         } else {
 680                 if (depth > FNHE_RECLAIM_DEPTH)
 681                         fnhe = fnhe_oldest(hash);
 682                 else {
 683                         fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
 684                         if (!fnhe)
 685                                 goto out_unlock;
 686
 687                         fnhe->fnhe_next = hash->chain;
 688                         rcu_assign_pointer(hash->chain, fnhe);
 689                 }
 690                 fnhe->fnhe_genid = genid;
 691                 fnhe->fnhe_daddr = daddr;
 692                 fnhe->fnhe_gw = gw;
 693                 fnhe->fnhe_pmtu = pmtu;
 694                 fnhe->fnhe_mtu_locked = lock;
 695                 fnhe->fnhe_expires = max(1UL, expires);
 696
 697                 /* Exception created; mark the cached routes for the nexthop
 698                  * stale, so anyone caching it rechecks if this exception
 699                  * applies to them.
 700                  */
 701                 rt = rcu_dereference(nhc->nhc_rth_input);
 702                 if (rt)
 703                         rt->dst.obsolete = DST_OBSOLETE_KILL;
 704
 705                 for_each_possible_cpu(i) {
 706                         struct rtable __rcu **prt;
 707
 708                         prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
 709                         rt = rcu_dereference(*prt);
 710                         if (rt)
 711                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 712                 }
 713         }
 714
 715         fnhe->fnhe_stamp = jiffies;
 716
 717 out_unlock:
 718         spin_unlock_bh(&fnhe_lock);
 719 }
 720
 721 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 722                              bool kill_route)
 723 {
 724         __be32 new_gw = icmp_hdr(skb)->un.gateway;
 725         __be32 old_gw = ip_hdr(skb)->saddr;
 726         struct net_device *dev = skb->dev;
 727         struct in_device *in_dev;
 728         struct fib_result res;
 729         struct neighbour *n;
 730         struct net *net;
 731
 732         switch (icmp_hdr(skb)->code & 7) {
 733         case ICMP_REDIR_NET:
 734         case ICMP_REDIR_NETTOS:
 735         case ICMP_REDIR_HOST:
 736         case ICMP_REDIR_HOSTTOS:
 737                 break;
 738
 739         default:
 740                 return;
 741         }
 742
 743         if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
 744                 return;
 745
 746         in_dev = __in_dev_get_rcu(dev);
 747         if (!in_dev)
 748                 return;
 749
 750         net = dev_net(dev);
 751         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
 752             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
 753             ipv4_is_zeronet(new_gw))
 754                 goto reject_redirect;
 755
 756         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
 757                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
 758                         goto reject_redirect;
 759                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
 760                         goto reject_redirect;
 761         } else {
 762                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
 763                         goto reject_redirect;
 764         }
 765
 766         n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
 767         if (!n)
 768                 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
 769         if (!IS_ERR(n)) {
 770                 if (!(n->nud_state & NUD_VALID)) {
 771                         neigh_event_send(n, NULL);
 772                 } else {
 773                         if (fib_lookup(net, fl4, &res, 0) == 0) {
 774                                 struct fib_nh_common *nhc;
 775
 776                                 fib_select_path(net, &res, fl4, skb);
 777                                 nhc = FIB_RES_NHC(res);
 778                                 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
 779                                                 0, false,
 780                                                 jiffies + ip_rt_gc_timeout);
 781                         }
 782                         if (kill_route)
 783                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 784                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 785                 }
 786                 neigh_release(n);
 787         }
 788         return;
 789
 790 reject_redirect:
 791 #ifdef CONFIG_IP_ROUTE_VERBOSE
 792         if (IN_DEV_LOG_MARTIANS(in_dev)) {
 793                 const struct iphdr *iph = (const struct iphdr *) skb->data;
 794                 __be32 daddr = iph->daddr;
 795                 __be32 saddr = iph->saddr;
 796
 797                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
 798                                      "  Advised path = %pI4 -> %pI4\n",
 799                                      &old_gw, dev->name, &new_gw,
 800                                      &saddr, &daddr);
 801         }
 802 #endif
 803         ;
 804 }
 805
 806 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
 807 {
 808         struct rtable *rt;
 809         struct flowi4 fl4;
 810         const struct iphdr *iph = (const struct iphdr *) skb->data;
 811         struct net *net = dev_net(skb->dev);
 812         int oif = skb->dev->ifindex;
 813         u8 tos = RT_TOS(iph->tos);
 814         u8 prot = iph->protocol;
 815         u32 mark = skb->mark;
 816
 817         rt = (struct rtable *) dst;
 818
 819         __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
 820         __ip_do_redirect(rt, skb, &fl4, true);
 821 }
 822
 823 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 824 {
 825         struct rtable *rt = (struct rtable *)dst;
 826         struct dst_entry *ret = dst;
 827
 828         if (rt) {
 829                 if (dst->obsolete > 0) {
 830                         ip_rt_put(rt);
 831                         ret = NULL;
 832                 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
 833                            rt->dst.expires) {
 834                         ip_rt_put(rt);
 835                         ret = NULL;
 836                 }
 837         }
 838         return ret;
 839 }
 840
 841 /*
 842  * Algorithm:
 843  *      1. The first ip_rt_redirect_number redirects are sent
 844  *         with exponential backoff, then we stop sending them at all,
 845  *         assuming that the host ignores our redirects.
 846  *      2. If we did not see packets requiring redirects
 847  *         during ip_rt_redirect_silence, we assume that the host
 848  *         forgot redirected route and start to send redirects again.
 849  *
 850  * This algorithm is much cheaper and more intelligent than dumb load limiting
 851  * in icmp.c.
 852  *
 853  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 854  * and "frag. need" (breaks PMTU discovery) in icmp.c.
 855  */
 856
 857 void ip_rt_send_redirect(struct sk_buff *skb)
 858 {
 859         struct rtable *rt = skb_rtable(skb);
 860         struct in_device *in_dev;
 861         struct inet_peer *peer;
 862         struct net *net;
 863         int log_martians;
 864         int vif;
 865
 866         rcu_read_lock();
 867         in_dev = __in_dev_get_rcu(rt->dst.dev);
 868         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
 869                 rcu_read_unlock();
 870                 return;
 871         }
 872         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
 873         vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
 874         rcu_read_unlock();
 875
 876         net = dev_net(rt->dst.dev);
 877         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
 878         if (!peer) {
 879                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
 880                           rt_nexthop(rt, ip_hdr(skb)->daddr));
 881                 return;
 882         }
 883
 884         /* No redirected packets during ip_rt_redirect_silence;
 885          * reset the algorithm.
 886          */
 887         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
 888                 peer->rate_tokens = 0;
 889                 peer->n_redirects = 0;
 890         }
 891
 892         /* Too many ignored redirects; do not send anything
 893          * set dst.rate_last to the last seen redirected packet.
 894          */
 895         if (peer->n_redirects >= ip_rt_redirect_number) {
 896                 peer->rate_last = jiffies;
 897                 goto out_put_peer;
 898         }
 899
 900         /* Check for load limit; set rate_last to the latest sent
 901          * redirect.
 902          */
 903         if (peer->n_redirects == 0 ||
 904             time_after(jiffies,
 905                        (peer->rate_last +
 906                         (ip_rt_redirect_load << peer->n_redirects)))) {
 907                 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
 908
 909                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 910                 peer->rate_last = jiffies;
 911                 ++peer->n_redirects;
 912 #ifdef CONFIG_IP_ROUTE_VERBOSE
 913                 if (log_martians &&
 914                     peer->n_redirects == ip_rt_redirect_number)
 915                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 916                                              &ip_hdr(skb)->saddr, inet_iif(skb),
 917                                              &ip_hdr(skb)->daddr, &gw);
 918 #endif
 919         }
 920 out_put_peer:
 921         inet_putpeer(peer);
 922 }
 923
 924 static int ip_error(struct sk_buff *skb)
 925 {
 926         struct rtable *rt = skb_rtable(skb);
 927         struct net_device *dev = skb->dev;
 928         struct in_device *in_dev;
 929         struct inet_peer *peer;
 930         unsigned long now;
 931         struct net *net;
 932         bool send;
 933         int code;
 934
 935         if (netif_is_l3_master(skb->dev)) {
 936                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
 937                 if (!dev)
 938                         goto out;
 939         }
 940
 941         in_dev = __in_dev_get_rcu(dev);
 942
 943         /* IP on this device is disabled. */
 944         if (!in_dev)
 945                 goto out;
 946
 947         net = dev_net(rt->dst.dev);
 948         if (!IN_DEV_FORWARD(in_dev)) {
 949                 switch (rt->dst.error) {
 950                 case EHOSTUNREACH:
 951                         __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
 952                         break;
 953
 954                 case ENETUNREACH:
 955                         __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 956                         break;
 957                 }
 958                 goto out;
 959         }
 960
 961         switch (rt->dst.error) {
 962         case EINVAL:
 963         default:
 964                 goto out;
 965         case EHOSTUNREACH:
 966                 code = ICMP_HOST_UNREACH;
 967                 break;
 968         case ENETUNREACH:
 969                 code = ICMP_NET_UNREACH;
 970                 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 971                 break;
 972         case EACCES:
 973                 code = ICMP_PKT_FILTERED;
 974                 break;
 975         }
 976
 977         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
 978                                l3mdev_master_ifindex(skb->dev), 1);
 979
 980         send = true;
 981         if (peer) {
 982                 now = jiffies;
 983                 peer->rate_tokens += now - peer->rate_last;
 984                 if (peer->rate_tokens > ip_rt_error_burst)
 985                         peer->rate_tokens = ip_rt_error_burst;
 986                 peer->rate_last = now;
 987                 if (peer->rate_tokens >= ip_rt_error_cost)
 988                         peer->rate_tokens -= ip_rt_error_cost;
 989                 else
 990                         send = false;
 991                 inet_putpeer(peer);
 992         }
 993         if (send)
 994                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
 995
 996 out:    kfree_skb(skb);
 997         return 0;
 998 }
 999
1000 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1001 {
1002         struct dst_entry *dst = &rt->dst;
1003         struct net *net = dev_net(dst->dev);
1004         struct fib_result res;
1005         bool lock = false;
1006         u32 old_mtu;
1007
1008         if (ip_mtu_locked(dst))
1009                 return;
1010
1011         old_mtu = ipv4_mtu(dst);
1012         if (old_mtu < mtu)
1013                 return;
1014
1015         if (mtu < ip_rt_min_pmtu) {
1016                 lock = true;
1017                 mtu = min(old_mtu, ip_rt_min_pmtu);
1018         }
1019
1020         if (rt->rt_pmtu == mtu && !lock &&
1021             time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1022                 return;
1023
1024         rcu_read_lock();
1025         if (fib_lookup(net, fl4, &res, 0) == 0) {
1026                 struct fib_nh_common *nhc;
1027
1028                 fib_select_path(net, &res, fl4, NULL);
1029                 nhc = FIB_RES_NHC(res);
1030                 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1031                                       jiffies + ip_rt_mtu_expires);
1032         }
1033         rcu_read_unlock();
1034 }
1035
1036 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1037                               struct sk_buff *skb, u32 mtu,
1038                               bool confirm_neigh)
1039 {
1040         struct rtable *rt = (struct rtable *) dst;
1041         struct flowi4 fl4;
1042
1043         ip_rt_build_flow_key(&fl4, sk, skb);
1044
1045         /* Don't make lookup fail for bridged encapsulations */
1046         if (skb && netif_is_any_bridge_port(skb->dev))
1047                 fl4.flowi4_oif = 0;
1048
1049         __ip_rt_update_pmtu(rt, &fl4, mtu);
1050 }
1051
1052 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1053                       int oif, u8 protocol)
1054 {
1055         const struct iphdr *iph = (const struct iphdr *)skb->data;
1056         struct flowi4 fl4;
1057         struct rtable *rt;
1058         u32 mark = IP4_REPLY_MARK(net, skb->mark);
1059
1060         __build_flow_key(net, &fl4, NULL, iph, oif,
1061                          RT_TOS(iph->tos), protocol, mark, 0);
1062         rt = __ip_route_output_key(net, &fl4);
1063         if (!IS_ERR(rt)) {
1064                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1065                 ip_rt_put(rt);
1066         }
1067 }
1068 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1069
1070 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1071 {
1072         const struct iphdr *iph = (const struct iphdr *)skb->data;
1073         struct flowi4 fl4;
1074         struct rtable *rt;
1075
1076         __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1077
1078         if (!fl4.flowi4_mark)
1079                 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1080
1081         rt = __ip_route_output_key(sock_net(sk), &fl4);
1082         if (!IS_ERR(rt)) {
1083                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1084                 ip_rt_put(rt);
1085         }
1086 }
1087
1088 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1089 {
1090         const struct iphdr *iph = (const struct iphdr *)skb->data;
1091         struct flowi4 fl4;
1092         struct rtable *rt;
1093         struct dst_entry *odst = NULL;
1094         bool new = false;
1095         struct net *net = sock_net(sk);
1096
1097         bh_lock_sock(sk);
1098
1099         if (!ip_sk_accept_pmtu(sk))
1100                 goto out;
1101
1102         odst = sk_dst_get(sk);
1103
1104         if (sock_owned_by_user(sk) || !odst) {
1105                 __ipv4_sk_update_pmtu(skb, sk, mtu);
1106                 goto out;
1107         }
1108
1109         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1110
1111         rt = (struct rtable *)odst;
1112         if (odst->obsolete && !odst->ops->check(odst, 0)) {
1113                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1114                 if (IS_ERR(rt))
1115                         goto out;
1116
1117                 new = true;
1118         }
1119
1120         __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu);
1121
1122         if (!dst_check(&rt->dst, 0)) {
1123                 if (new)
1124                         dst_release(&rt->dst);
1125
1126                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1127                 if (IS_ERR(rt))
1128                         goto out;
1129
1130                 new = true;
1131         }
1132
1133         if (new)
1134                 sk_dst_set(sk, &rt->dst);
1135
1136 out:
1137         bh_unlock_sock(sk);
1138         dst_release(odst);
1139 }
1140 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1141
1142 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1143                    int oif, u8 protocol)
1144 {
1145         const struct iphdr *iph = (const struct iphdr *)skb->data;
1146         struct flowi4 fl4;
1147         struct rtable *rt;
1148
1149         __build_flow_key(net, &fl4, NULL, iph, oif,
1150                          RT_TOS(iph->tos), protocol, 0, 0);
1151         rt = __ip_route_output_key(net, &fl4);
1152         if (!IS_ERR(rt)) {
1153                 __ip_do_redirect(rt, skb, &fl4, false);
1154                 ip_rt_put(rt);
1155         }
1156 }
1157 EXPORT_SYMBOL_GPL(ipv4_redirect);
1158
1159 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1160 {
1161         const struct iphdr *iph = (const struct iphdr *)skb->data;
1162         struct flowi4 fl4;
1163         struct rtable *rt;
1164         struct net *net = sock_net(sk);
1165
1166         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1167         rt = __ip_route_output_key(net, &fl4);
1168         if (!IS_ERR(rt)) {
1169                 __ip_do_redirect(rt, skb, &fl4, false);
1170                 ip_rt_put(rt);
1171         }
1172 }
1173 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1174
1175 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1176                                                          u32 cookie)
1177 {
1178         struct rtable *rt = (struct rtable *) dst;
1179
1180         /* All IPV4 dsts are created with ->obsolete set to the value
1181          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1182          * into this function always.
1183          *
1184          * When a PMTU/redirect information update invalidates a route,
1185          * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1186          * DST_OBSOLETE_DEAD.
1187          */
1188         if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1189                 return NULL;
1190         return dst;
1191 }
1192 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1193
1194 static void ipv4_send_dest_unreach(struct sk_buff *skb)
1195 {
1196         struct ip_options opt;
1197         int res;
1198
1199         /* Recompile ip options since IPCB may not be valid anymore.
1200          * Also check we have a reasonable ipv4 header.
1201          */
1202         if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1203             ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1204                 return;
1205
1206         memset(&opt, 0, sizeof(opt));
1207         if (ip_hdr(skb)->ihl > 5) {
1208                 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1209                         return;
1210                 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1211
1212                 rcu_read_lock();
1213                 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1214                 rcu_read_unlock();
1215
1216                 if (res)
1217                         return;
1218         }
1219         __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1220 }
1221
1222 static void ipv4_link_failure(struct sk_buff *skb)
1223 {
1224         struct rtable *rt;
1225
1226         ipv4_send_dest_unreach(skb);
1227
1228         rt = skb_rtable(skb);
1229         if (rt)
1230                 dst_set_expires(&rt->dst, 0);
1231 }
1232
1233 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1234 {
1235         pr_debug("%s: %pI4 -> %pI4, %s\n",
1236                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1237                  skb->dev ? skb->dev->name : "?");
1238         kfree_skb(skb);
1239         WARN_ON(1);
1240         return 0;
1241 }
1242
1243 /*
1244  * We do not cache source address of outgoing interface,
1245  * because it is used only by IP RR, TS and SRR options,
1246  * so that it out of fast path.
1247  *
1248  * BTW remember: "addr" is allowed to be not aligned
1249  * in IP options!
1250  */
1251
1252 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1253 {
1254         __be32 src;
1255
1256         if (rt_is_output_route(rt))
1257                 src = ip_hdr(skb)->saddr;
1258         else {
1259                 struct fib_result res;
1260                 struct iphdr *iph = ip_hdr(skb);
1261                 struct flowi4 fl4 = {
1262                         .daddr = iph->daddr,
1263                         .saddr = iph->saddr,
1264                         .flowi4_tos = RT_TOS(iph->tos),
1265                         .flowi4_oif = rt->dst.dev->ifindex,
1266                         .flowi4_iif = skb->dev->ifindex,
1267                         .flowi4_mark = skb->mark,
1268                 };
1269
1270                 rcu_read_lock();
1271                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1272                         src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1273                 else
1274                         src = inet_select_addr(rt->dst.dev,
1275                                                rt_nexthop(rt, iph->daddr),
1276                                                RT_SCOPE_UNIVERSE);
1277                 rcu_read_unlock();
1278         }
1279         memcpy(addr, &src, 4);
1280 }
1281
1282 #ifdef CONFIG_IP_ROUTE_CLASSID
1283 static void set_class_tag(struct rtable *rt, u32 tag)
1284 {
1285         if (!(rt->dst.tclassid & 0xFFFF))
1286                 rt->dst.tclassid |= tag & 0xFFFF;
1287         if (!(rt->dst.tclassid & 0xFFFF0000))
1288                 rt->dst.tclassid |= tag & 0xFFFF0000;
1289 }
1290 #endif
1291
1292 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1293 {
1294         unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1295         unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1296                                     ip_rt_min_advmss);
1297
1298         return min(advmss, IPV4_MAX_PMTU - header_size);
1299 }
1300
1301 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1302 {
1303         return ip_dst_mtu_maybe_forward(dst, false);
1304 }
1305 EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1306
1307 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1308 {
1309         struct fnhe_hash_bucket *hash;
1310         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1311         u32 hval = fnhe_hashfun(daddr);
1312
1313         spin_lock_bh(&fnhe_lock);
1314
1315         hash = rcu_dereference_protected(nhc->nhc_exceptions,
1316                                          lockdep_is_held(&fnhe_lock));
1317         hash += hval;
1318
1319         fnhe_p = &hash->chain;
1320         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1321         while (fnhe) {
1322                 if (fnhe->fnhe_daddr == daddr) {
1323                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1324                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1325                         /* set fnhe_daddr to 0 to ensure it won't bind with
1326                          * new dsts in rt_bind_exception().
1327                          */
1328                         fnhe->fnhe_daddr = 0;
1329                         fnhe_flush_routes(fnhe);
1330                         kfree_rcu(fnhe, rcu);
1331                         break;
1332                 }
1333                 fnhe_p = &fnhe->fnhe_next;
1334                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1335                                                  lockdep_is_held(&fnhe_lock));
1336         }
1337
1338         spin_unlock_bh(&fnhe_lock);
1339 }
1340
1341 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1342                                                __be32 daddr)
1343 {
1344         struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1345         struct fib_nh_exception *fnhe;
1346         u32 hval;
1347
1348         if (!hash)
1349                 return NULL;
1350
1351         hval = fnhe_hashfun(daddr);
1352
1353         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1354              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1355                 if (fnhe->fnhe_daddr == daddr) {
1356                         if (fnhe->fnhe_expires &&
1357                             time_after(jiffies, fnhe->fnhe_expires)) {
1358                                 ip_del_fnhe(nhc, daddr);
1359                                 break;
1360                         }
1361                         return fnhe;
1362                 }
1363         }
1364         return NULL;
1365 }
1366
1367 /* MTU selection:
1368  * 1. mtu on route is locked - use it
1369  * 2. mtu from nexthop exception
1370  * 3. mtu from egress device
1371  */
1372
1373 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1374 {
1375         struct fib_nh_common *nhc = res->nhc;
1376         struct net_device *dev = nhc->nhc_dev;
1377         struct fib_info *fi = res->fi;
1378         u32 mtu = 0;
1379
1380         if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1381             fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1382                 mtu = fi->fib_mtu;
1383
1384         if (likely(!mtu)) {
1385                 struct fib_nh_exception *fnhe;
1386
1387                 fnhe = find_exception(nhc, daddr);
1388                 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1389                         mtu = fnhe->fnhe_pmtu;
1390         }
1391
1392         if (likely(!mtu))
1393                 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1394
1395         return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1396 }
1397
1398 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1399                               __be32 daddr, const bool do_cache)
1400 {
1401         bool ret = false;
1402
1403         spin_lock_bh(&fnhe_lock);
1404
1405         if (daddr == fnhe->fnhe_daddr) {
1406                 struct rtable __rcu **porig;
1407                 struct rtable *orig;
1408                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1409
1410                 if (rt_is_input_route(rt))
1411                         porig = &fnhe->fnhe_rth_input;
1412                 else
1413                         porig = &fnhe->fnhe_rth_output;
1414                 orig = rcu_dereference(*porig);
1415
1416                 if (fnhe->fnhe_genid != genid) {
1417                         fnhe->fnhe_genid = genid;
1418                         fnhe->fnhe_gw = 0;
1419                         fnhe->fnhe_pmtu = 0;
1420                         fnhe->fnhe_expires = 0;
1421                         fnhe->fnhe_mtu_locked = false;
1422                         fnhe_flush_routes(fnhe);
1423                         orig = NULL;
1424                 }
1425                 fill_route_from_fnhe(rt, fnhe);
1426                 if (!rt->rt_gw4) {
1427                         rt->rt_gw4 = daddr;
1428                         rt->rt_gw_family = AF_INET;
1429                 }
1430
1431                 if (do_cache) {
1432                         dst_hold(&rt->dst);
1433                         rcu_assign_pointer(*porig, rt);
1434                         if (orig) {
1435                                 dst_dev_put(&orig->dst);
1436                                 dst_release(&orig->dst);
1437                         }
1438                         ret = true;
1439                 }
1440
1441                 fnhe->fnhe_stamp = jiffies;
1442         }
1443         spin_unlock_bh(&fnhe_lock);
1444
1445         return ret;
1446 }
1447
1448 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1449 {
1450         struct rtable *orig, *prev, **p;
1451         bool ret = true;
1452
1453         if (rt_is_input_route(rt)) {
1454                 p = (struct rtable **)&nhc->nhc_rth_input;
1455         } else {
1456                 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1457         }
1458         orig = *p;
1459
1460         /* hold dst before doing cmpxchg() to avoid race condition
1461          * on this dst
1462          */
1463         dst_hold(&rt->dst);
1464         prev = cmpxchg(p, orig, rt);
1465         if (prev == orig) {
1466                 if (orig) {
1467                         rt_add_uncached_list(orig);
1468                         dst_release(&orig->dst);
1469                 }
1470         } else {
1471                 dst_release(&rt->dst);
1472                 ret = false;
1473         }
1474
1475         return ret;
1476 }
1477
1478 struct uncached_list {
1479         spinlock_t              lock;
1480         struct list_head        head;
1481 };
1482
1483 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1484
1485 void rt_add_uncached_list(struct rtable *rt)
1486 {
1487         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1488
1489         rt->rt_uncached_list = ul;
1490
1491         spin_lock_bh(&ul->lock);
1492         list_add_tail(&rt->rt_uncached, &ul->head);
1493         spin_unlock_bh(&ul->lock);
1494 }
1495
1496 void rt_del_uncached_list(struct rtable *rt)
1497 {
1498         if (!list_empty(&rt->rt_uncached)) {
1499                 struct uncached_list *ul = rt->rt_uncached_list;
1500
1501                 spin_lock_bh(&ul->lock);
1502                 list_del(&rt->rt_uncached);
1503                 spin_unlock_bh(&ul->lock);
1504         }
1505 }
1506
1507 static void ipv4_dst_destroy(struct dst_entry *dst)
1508 {
1509         struct rtable *rt = (struct rtable *)dst;
1510
1511         ip_dst_metrics_put(dst);
1512         rt_del_uncached_list(rt);
1513 }
1514
1515 void rt_flush_dev(struct net_device *dev)
1516 {
1517         struct rtable *rt;
1518         int cpu;
1519
1520         for_each_possible_cpu(cpu) {
1521                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1522
1523                 spin_lock_bh(&ul->lock);
1524                 list_for_each_entry(rt, &ul->head, rt_uncached) {
1525                         if (rt->dst.dev != dev)
1526                                 continue;
1527                         rt->dst.dev = blackhole_netdev;
1528                         dev_hold(rt->dst.dev);
1529                         dev_put(dev);
1530                 }
1531                 spin_unlock_bh(&ul->lock);
1532         }
1533 }
1534
1535 static bool rt_cache_valid(const struct rtable *rt)
1536 {
1537         return  rt &&
1538                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1539                 !rt_is_expired(rt);
1540 }
1541
1542 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1543                            const struct fib_result *res,
1544                            struct fib_nh_exception *fnhe,
1545                            struct fib_info *fi, u16 type, u32 itag,
1546                            const bool do_cache)
1547 {
1548         bool cached = false;
1549
1550         if (fi) {
1551                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1552
1553                 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1554                         rt->rt_uses_gateway = 1;
1555                         rt->rt_gw_family = nhc->nhc_gw_family;
1556                         /* only INET and INET6 are supported */
1557                         if (likely(nhc->nhc_gw_family == AF_INET))
1558                                 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1559                         else
1560                                 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1561                 }
1562
1563                 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1564
1565 #ifdef CONFIG_IP_ROUTE_CLASSID
1566                 if (nhc->nhc_family == AF_INET) {
1567                         struct fib_nh *nh;
1568
1569                         nh = container_of(nhc, struct fib_nh, nh_common);
1570                         rt->dst.tclassid = nh->nh_tclassid;
1571                 }
1572 #endif
1573                 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1574                 if (unlikely(fnhe))
1575                         cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1576                 else if (do_cache)
1577                         cached = rt_cache_route(nhc, rt);
1578                 if (unlikely(!cached)) {
1579                         /* Routes we intend to cache in nexthop exception or
1580                          * FIB nexthop have the DST_NOCACHE bit clear.
1581                          * However, if we are unsuccessful at storing this
1582                          * route into the cache we really need to set it.
1583                          */
1584                         if (!rt->rt_gw4) {
1585                                 rt->rt_gw_family = AF_INET;
1586                                 rt->rt_gw4 = daddr;
1587                         }
1588                         rt_add_uncached_list(rt);
1589                 }
1590         } else
1591                 rt_add_uncached_list(rt);
1592
1593 #ifdef CONFIG_IP_ROUTE_CLASSID
1594 #ifdef CONFIG_IP_MULTIPLE_TABLES
1595         set_class_tag(rt, res->tclassid);
1596 #endif
1597         set_class_tag(rt, itag);
1598 #endif
1599 }
1600
1601 struct rtable *rt_dst_alloc(struct net_device *dev,
1602                             unsigned int flags, u16 type,
1603                             bool nopolicy, bool noxfrm)
1604 {
1605         struct rtable *rt;
1606
1607         rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1608                        (nopolicy ? DST_NOPOLICY : 0) |
1609                        (noxfrm ? DST_NOXFRM : 0));
1610
1611         if (rt) {
1612                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1613                 rt->rt_flags = flags;
1614                 rt->rt_type = type;
1615                 rt->rt_is_input = 0;
1616                 rt->rt_iif = 0;
1617                 rt->rt_pmtu = 0;
1618                 rt->rt_mtu_locked = 0;
1619                 rt->rt_uses_gateway = 0;
1620                 rt->rt_gw_family = 0;
1621                 rt->rt_gw4 = 0;
1622                 INIT_LIST_HEAD(&rt->rt_uncached);
1623
1624                 rt->dst.output = ip_output;
1625                 if (flags & RTCF_LOCAL)
1626                         rt->dst.input = ip_local_deliver;
1627         }
1628
1629         return rt;
1630 }
1631 EXPORT_SYMBOL(rt_dst_alloc);
1632
1633 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1634 {
1635         struct rtable *new_rt;
1636
1637         new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1638                            rt->dst.flags);
1639
1640         if (new_rt) {
1641                 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1642                 new_rt->rt_flags = rt->rt_flags;
1643                 new_rt->rt_type = rt->rt_type;
1644                 new_rt->rt_is_input = rt->rt_is_input;
1645                 new_rt->rt_iif = rt->rt_iif;
1646                 new_rt->rt_pmtu = rt->rt_pmtu;
1647                 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1648                 new_rt->rt_gw_family = rt->rt_gw_family;
1649                 if (rt->rt_gw_family == AF_INET)
1650                         new_rt->rt_gw4 = rt->rt_gw4;
1651                 else if (rt->rt_gw_family == AF_INET6)
1652                         new_rt->rt_gw6 = rt->rt_gw6;
1653                 INIT_LIST_HEAD(&new_rt->rt_uncached);
1654
1655                 new_rt->dst.input = rt->dst.input;
1656                 new_rt->dst.output = rt->dst.output;
1657                 new_rt->dst.error = rt->dst.error;
1658                 new_rt->dst.lastuse = jiffies;
1659                 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1660         }
1661         return new_rt;
1662 }
1663 EXPORT_SYMBOL(rt_dst_clone);
1664
1665 /* called in rcu_read_lock() section */
1666 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1667                           u8 tos, struct net_device *dev,
1668                           struct in_device *in_dev, u32 *itag)
1669 {
1670         int err;
1671
1672         /* Primary sanity checks. */
1673         if (!in_dev)
1674                 return -EINVAL;
1675
1676         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1677             skb->protocol != htons(ETH_P_IP))
1678                 return -EINVAL;
1679
1680         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1681                 return -EINVAL;
1682
1683         if (ipv4_is_zeronet(saddr)) {
1684                 if (!ipv4_is_local_multicast(daddr) &&
1685                     ip_hdr(skb)->protocol != IPPROTO_IGMP)
1686                         return -EINVAL;
1687         } else {
1688                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1689                                           in_dev, itag);
1690                 if (err < 0)
1691                         return err;
1692         }
1693         return 0;
1694 }
1695
1696 /* called in rcu_read_lock() section */
1697 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1698                              u8 tos, struct net_device *dev, int our)
1699 {
1700         struct in_device *in_dev = __in_dev_get_rcu(dev);
1701         unsigned int flags = RTCF_MULTICAST;
1702         struct rtable *rth;
1703         u32 itag = 0;
1704         int err;
1705
1706         err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1707         if (err)
1708                 return err;
1709
1710         if (our)
1711                 flags |= RTCF_LOCAL;
1712
1713         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1714                            IN_DEV_ORCONF(in_dev, NOPOLICY), false);
1715         if (!rth)
1716                 return -ENOBUFS;
1717
1718 #ifdef CONFIG_IP_ROUTE_CLASSID
1719         rth->dst.tclassid = itag;
1720 #endif
1721         rth->dst.output = ip_rt_bug;
1722         rth->rt_is_input= 1;
1723
1724 #ifdef CONFIG_IP_MROUTE
1725         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1726                 rth->dst.input = ip_mr_input;
1727 #endif
1728         RT_CACHE_STAT_INC(in_slow_mc);
1729
1730         skb_dst_set(skb, &rth->dst);
1731         return 0;
1732 }
1733
1734
1735 static void ip_handle_martian_source(struct net_device *dev,
1736                                      struct in_device *in_dev,
1737                                      struct sk_buff *skb,
1738                                      __be32 daddr,
1739                                      __be32 saddr)
1740 {
1741         RT_CACHE_STAT_INC(in_martian_src);
1742 #ifdef CONFIG_IP_ROUTE_VERBOSE
1743         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1744                 /*
1745                  *      RFC1812 recommendation, if source is martian,
1746                  *      the only hint is MAC header.
1747                  */
1748                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1749                         &daddr, &saddr, dev->name);
1750                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1751                         print_hex_dump(KERN_WARNING, "ll header: ",
1752                                        DUMP_PREFIX_OFFSET, 16, 1,
1753                                        skb_mac_header(skb),
1754                                        dev->hard_header_len, false);
1755                 }
1756         }
1757 #endif
1758 }
1759
1760 /* called in rcu_read_lock() section */
1761 static int __mkroute_input(struct sk_buff *skb,
1762                            const struct fib_result *res,
1763                            struct in_device *in_dev,
1764                            __be32 daddr, __be32 saddr, u32 tos)
1765 {
1766         struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1767         struct net_device *dev = nhc->nhc_dev;
1768         struct fib_nh_exception *fnhe;
1769         struct rtable *rth;
1770         int err;
1771         struct in_device *out_dev;
1772         bool do_cache;
1773         u32 itag = 0;
1774
1775         /* get a working reference to the output device */
1776         out_dev = __in_dev_get_rcu(dev);
1777         if (!out_dev) {
1778                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1779                 return -EINVAL;
1780         }
1781
1782         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1783                                   in_dev->dev, in_dev, &itag);
1784         if (err < 0) {
1785                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1786                                          saddr);
1787
1788                 goto cleanup;
1789         }
1790
1791         do_cache = res->fi && !itag;
1792         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1793             skb->protocol == htons(ETH_P_IP)) {
1794                 __be32 gw;
1795
1796                 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1797                 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1798                     inet_addr_onlink(out_dev, saddr, gw))
1799                         IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1800         }
1801
1802         if (skb->protocol != htons(ETH_P_IP)) {
1803                 /* Not IP (i.e. ARP). Do not create route, if it is
1804                  * invalid for proxy arp. DNAT routes are always valid.
1805                  *
1806                  * Proxy arp feature have been extended to allow, ARP
1807                  * replies back to the same interface, to support
1808                  * Private VLAN switch technologies. See arp.c.
1809                  */
1810                 if (out_dev == in_dev &&
1811                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1812                         err = -EINVAL;
1813                         goto cleanup;
1814                 }
1815         }
1816
1817         fnhe = find_exception(nhc, daddr);
1818         if (do_cache) {
1819                 if (fnhe)
1820                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1821                 else
1822                         rth = rcu_dereference(nhc->nhc_rth_input);
1823                 if (rt_cache_valid(rth)) {
1824                         skb_dst_set_noref(skb, &rth->dst);
1825                         goto out;
1826                 }
1827         }
1828
1829         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1830                            IN_DEV_ORCONF(in_dev, NOPOLICY),
1831                            IN_DEV_ORCONF(out_dev, NOXFRM));
1832         if (!rth) {
1833                 err = -ENOBUFS;
1834                 goto cleanup;
1835         }
1836
1837         rth->rt_is_input = 1;
1838         RT_CACHE_STAT_INC(in_slow_tot);
1839
1840         rth->dst.input = ip_forward;
1841
1842         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1843                        do_cache);
1844         lwtunnel_set_redirect(&rth->dst);
1845         skb_dst_set(skb, &rth->dst);
1846 out:
1847         err = 0;
1848  cleanup:
1849         return err;
1850 }
1851
1852 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1853 /* To make ICMP packets follow the right flow, the multipath hash is
1854  * calculated from the inner IP addresses.
1855  */
1856 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1857                                  struct flow_keys *hash_keys)
1858 {
1859         const struct iphdr *outer_iph = ip_hdr(skb);
1860         const struct iphdr *key_iph = outer_iph;
1861         const struct iphdr *inner_iph;
1862         const struct icmphdr *icmph;
1863         struct iphdr _inner_iph;
1864         struct icmphdr _icmph;
1865
1866         if (likely(outer_iph->protocol != IPPROTO_ICMP))
1867                 goto out;
1868
1869         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1870                 goto out;
1871
1872         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1873                                    &_icmph);
1874         if (!icmph)
1875                 goto out;
1876
1877         if (!icmp_is_err(icmph->type))
1878                 goto out;
1879
1880         inner_iph = skb_header_pointer(skb,
1881                                        outer_iph->ihl * 4 + sizeof(_icmph),
1882                                        sizeof(_inner_iph), &_inner_iph);
1883         if (!inner_iph)
1884                 goto out;
1885
1886         key_iph = inner_iph;
1887 out:
1888         hash_keys->addrs.v4addrs.src = key_iph->saddr;
1889         hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1890 }
1891
1892 static u32 fib_multipath_custom_hash_outer(const struct net *net,
1893                                            const struct sk_buff *skb,
1894                                            bool *p_has_inner)
1895 {
1896         u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
1897         struct flow_keys keys, hash_keys;
1898
1899         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1900                 return 0;
1901
1902         memset(&hash_keys, 0, sizeof(hash_keys));
1903         skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1904
1905         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1906         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1907                 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1908         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1909                 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1910         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1911                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1912         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1913                 hash_keys.ports.src = keys.ports.src;
1914         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1915                 hash_keys.ports.dst = keys.ports.dst;
1916
1917         *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1918         return flow_hash_from_keys(&hash_keys);
1919 }
1920
1921 static u32 fib_multipath_custom_hash_inner(const struct net *net,
1922                                            const struct sk_buff *skb,
1923                                            bool has_inner)
1924 {
1925         u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
1926         struct flow_keys keys, hash_keys;
1927
1928         /* We assume the packet carries an encapsulation, but if none was
1929          * encountered during dissection of the outer flow, then there is no
1930          * point in calling the flow dissector again.
1931          */
1932         if (!has_inner)
1933                 return 0;
1934
1935         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1936                 return 0;
1937
1938         memset(&hash_keys, 0, sizeof(hash_keys));
1939         skb_flow_dissect_flow_keys(skb, &keys, 0);
1940
1941         if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1942                 return 0;
1943
1944         if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1945                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1946                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1947                         hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1948                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1949                         hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1950         } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1951                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1952                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1953                         hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1954                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1955                         hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1956                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1957                         hash_keys.tags.flow_label = keys.tags.flow_label;
1958         }
1959
1960         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1961                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1962         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1963                 hash_keys.ports.src = keys.ports.src;
1964         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1965                 hash_keys.ports.dst = keys.ports.dst;
1966
1967         return flow_hash_from_keys(&hash_keys);
1968 }
1969
1970 static u32 fib_multipath_custom_hash_skb(const struct net *net,
1971                                          const struct sk_buff *skb)
1972 {
1973         u32 mhash, mhash_inner;
1974         bool has_inner = true;
1975
1976         mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
1977         mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
1978
1979         return jhash_2words(mhash, mhash_inner, 0);
1980 }
1981
1982 static u32 fib_multipath_custom_hash_fl4(const struct net *net,
1983                                          const struct flowi4 *fl4)
1984 {
1985         u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
1986         struct flow_keys hash_keys;
1987
1988         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1989                 return 0;
1990
1991         memset(&hash_keys, 0, sizeof(hash_keys));
1992         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1993         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1994                 hash_keys.addrs.v4addrs.src = fl4->saddr;
1995         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1996                 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1997         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1998                 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1999         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2000                 hash_keys.ports.src = fl4->fl4_sport;
2001         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2002                 hash_keys.ports.dst = fl4->fl4_dport;
2003
2004         return flow_hash_from_keys(&hash_keys);
2005 }
2006
2007 /* if skb is set it will be used and fl4 can be NULL */
2008 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2009                        const struct sk_buff *skb, struct flow_keys *flkeys)
2010 {
2011         u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2012         struct flow_keys hash_keys;
2013         u32 mhash = 0;
2014
2015         switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
2016         case 0:
2017                 memset(&hash_keys, 0, sizeof(hash_keys));
2018                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2019                 if (skb) {
2020                         ip_multipath_l3_keys(skb, &hash_keys);
2021                 } else {
2022                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2023                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2024                 }
2025                 mhash = flow_hash_from_keys(&hash_keys);
2026                 break;
2027         case 1:
2028                 /* skb is currently provided only when forwarding */
2029                 if (skb) {
2030                         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2031                         struct flow_keys keys;
2032
2033                         /* short-circuit if we already have L4 hash present */
2034                         if (skb->l4_hash)
2035                                 return skb_get_hash_raw(skb) >> 1;
2036
2037                         memset(&hash_keys, 0, sizeof(hash_keys));
2038
2039                         if (!flkeys) {
2040                                 skb_flow_dissect_flow_keys(skb, &keys, flag);
2041                                 flkeys = &keys;
2042                         }
2043
2044                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2045                         hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2046                         hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2047                         hash_keys.ports.src = flkeys->ports.src;
2048                         hash_keys.ports.dst = flkeys->ports.dst;
2049                         hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2050                 } else {
2051                         memset(&hash_keys, 0, sizeof(hash_keys));
2052                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2053                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2054                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2055                         hash_keys.ports.src = fl4->fl4_sport;
2056                         hash_keys.ports.dst = fl4->fl4_dport;
2057                         hash_keys.basic.ip_proto = fl4->flowi4_proto;
2058                 }
2059                 mhash = flow_hash_from_keys(&hash_keys);
2060                 break;
2061         case 2:
2062                 memset(&hash_keys, 0, sizeof(hash_keys));
2063                 /* skb is currently provided only when forwarding */
2064                 if (skb) {
2065                         struct flow_keys keys;
2066
2067                         skb_flow_dissect_flow_keys(skb, &keys, 0);
2068                         /* Inner can be v4 or v6 */
2069                         if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2070                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2071                                 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2072                                 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2073                         } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2074                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2075                                 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2076                                 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2077                                 hash_keys.tags.flow_label = keys.tags.flow_label;
2078                                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2079                         } else {
2080                                 /* Same as case 0 */
2081                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2082                                 ip_multipath_l3_keys(skb, &hash_keys);
2083                         }
2084                 } else {
2085                         /* Same as case 0 */
2086                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2087                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2088                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2089                 }
2090                 mhash = flow_hash_from_keys(&hash_keys);
2091                 break;
2092         case 3:
2093                 if (skb)
2094                         mhash = fib_multipath_custom_hash_skb(net, skb);
2095                 else
2096                         mhash = fib_multipath_custom_hash_fl4(net, fl4);
2097                 break;
2098         }
2099
2100         if (multipath_hash)
2101                 mhash = jhash_2words(mhash, multipath_hash, 0);
2102
2103         return mhash >> 1;
2104 }
2105 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2106
2107 static int ip_mkroute_input(struct sk_buff *skb,
2108                             struct fib_result *res,
2109                             struct in_device *in_dev,
2110                             __be32 daddr, __be32 saddr, u32 tos,
2111                             struct flow_keys *hkeys)
2112 {
2113 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2114         if (res->fi && fib_info_num_path(res->fi) > 1) {
2115                 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2116
2117                 fib_select_multipath(res, h);
2118         }
2119 #endif
2120
2121         /* create a routing cache entry */
2122         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2123 }
2124
2125 /* Implements all the saddr-related checks as ip_route_input_slow(),
2126  * assuming daddr is valid and the destination is not a local broadcast one.
2127  * Uses the provided hint instead of performing a route lookup.
2128  */
2129 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2130                       u8 tos, struct net_device *dev,
2131                       const struct sk_buff *hint)
2132 {
2133         struct in_device *in_dev = __in_dev_get_rcu(dev);
2134         struct rtable *rt = skb_rtable(hint);
2135         struct net *net = dev_net(dev);
2136         int err = -EINVAL;
2137         u32 tag = 0;
2138
2139         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2140                 goto martian_source;
2141
2142         if (ipv4_is_zeronet(saddr))
2143                 goto martian_source;
2144
2145         if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2146                 goto martian_source;
2147
2148         if (rt->rt_type != RTN_LOCAL)
2149                 goto skip_validate_source;
2150
2151         tos &= IPTOS_RT_MASK;
2152         err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2153         if (err < 0)
2154                 goto martian_source;
2155
2156 skip_validate_source:
2157         skb_dst_copy(skb, hint);
2158         return 0;
2159
2160 martian_source:
2161         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2162         return err;
2163 }
2164
2165 /* get device for dst_alloc with local routes */
2166 static struct net_device *ip_rt_get_dev(struct net *net,
2167                                         const struct fib_result *res)
2168 {
2169         struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2170         struct net_device *dev = NULL;
2171
2172         if (nhc)
2173                 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2174
2175         return dev ? : net->loopback_dev;
2176 }
2177
2178 /*
2179  *      NOTE. We drop all the packets that has local source
2180  *      addresses, because every properly looped back packet
2181  *      must have correct destination already attached by output routine.
2182  *      Changes in the enforced policies must be applied also to
2183  *      ip_route_use_hint().
2184  *
2185  *      Such approach solves two big problems:
2186  *      1. Not simplex devices are handled properly.
2187  *      2. IP spoofing attempts are filtered with 100% of guarantee.
2188  *      called with rcu_read_lock()
2189  */
2190
2191 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2192                                u8 tos, struct net_device *dev,
2193                                struct fib_result *res)
2194 {
2195         struct in_device *in_dev = __in_dev_get_rcu(dev);
2196         struct flow_keys *flkeys = NULL, _flkeys;
2197         struct net    *net = dev_net(dev);
2198         struct ip_tunnel_info *tun_info;
2199         int             err = -EINVAL;
2200         unsigned int    flags = 0;
2201         u32             itag = 0;
2202         struct rtable   *rth;
2203         struct flowi4   fl4;
2204         bool do_cache = true;
2205
2206         /* IP on this device is disabled. */
2207
2208         if (!in_dev)
2209                 goto out;
2210
2211         /* Check for the most weird martians, which can be not detected
2212          * by fib_lookup.
2213          */
2214
2215         tun_info = skb_tunnel_info(skb);
2216         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2217                 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2218         else
2219                 fl4.flowi4_tun_key.tun_id = 0;
2220         skb_dst_drop(skb);
2221
2222         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2223                 goto martian_source;
2224
2225         res->fi = NULL;
2226         res->table = NULL;
2227         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2228                 goto brd_input;
2229
2230         /* Accept zero addresses only to limited broadcast;
2231          * I even do not know to fix it or not. Waiting for complains :-)
2232          */
2233         if (ipv4_is_zeronet(saddr))
2234                 goto martian_source;
2235
2236         if (ipv4_is_zeronet(daddr))
2237                 goto martian_destination;
2238
2239         /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2240          * and call it once if daddr or/and saddr are loopback addresses
2241          */
2242         if (ipv4_is_loopback(daddr)) {
2243                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2244                         goto martian_destination;
2245         } else if (ipv4_is_loopback(saddr)) {
2246                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2247                         goto martian_source;
2248         }
2249
2250         /*
2251          *      Now we are ready to route packet.
2252          */
2253         fl4.flowi4_oif = 0;
2254         fl4.flowi4_iif = dev->ifindex;
2255         fl4.flowi4_mark = skb->mark;
2256         fl4.flowi4_tos = tos;
2257         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2258         fl4.flowi4_flags = 0;
2259         fl4.daddr = daddr;
2260         fl4.saddr = saddr;
2261         fl4.flowi4_uid = sock_net_uid(net, NULL);
2262         fl4.flowi4_multipath_hash = 0;
2263
2264         if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2265                 flkeys = &_flkeys;
2266         } else {
2267                 fl4.flowi4_proto = 0;
2268                 fl4.fl4_sport = 0;
2269                 fl4.fl4_dport = 0;
2270         }
2271
2272         err = fib_lookup(net, &fl4, res, 0);
2273         if (err != 0) {
2274                 if (!IN_DEV_FORWARD(in_dev))
2275                         err = -EHOSTUNREACH;
2276                 goto no_route;
2277         }
2278
2279         if (res->type == RTN_BROADCAST) {
2280                 if (IN_DEV_BFORWARD(in_dev))
2281                         goto make_route;
2282                 /* not do cache if bc_forwarding is enabled */
2283                 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2284                         do_cache = false;
2285                 goto brd_input;
2286         }
2287
2288         if (res->type == RTN_LOCAL) {
2289                 err = fib_validate_source(skb, saddr, daddr, tos,
2290                                           0, dev, in_dev, &itag);
2291                 if (err < 0)
2292                         goto martian_source;
2293                 goto local_input;
2294         }
2295
2296         if (!IN_DEV_FORWARD(in_dev)) {
2297                 err = -EHOSTUNREACH;
2298                 goto no_route;
2299         }
2300         if (res->type != RTN_UNICAST)
2301                 goto martian_destination;
2302
2303 make_route:
2304         err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2305 out:    return err;
2306
2307 brd_input:
2308         if (skb->protocol != htons(ETH_P_IP))
2309                 goto e_inval;
2310
2311         if (!ipv4_is_zeronet(saddr)) {
2312                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2313                                           in_dev, &itag);
2314                 if (err < 0)
2315                         goto martian_source;
2316         }
2317         flags |= RTCF_BROADCAST;
2318         res->type = RTN_BROADCAST;
2319         RT_CACHE_STAT_INC(in_brd);
2320
2321 local_input:
2322         do_cache &= res->fi && !itag;
2323         if (do_cache) {
2324                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2325
2326                 rth = rcu_dereference(nhc->nhc_rth_input);
2327                 if (rt_cache_valid(rth)) {
2328                         skb_dst_set_noref(skb, &rth->dst);
2329                         err = 0;
2330                         goto out;
2331                 }
2332         }
2333
2334         rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2335                            flags | RTCF_LOCAL, res->type,
2336                            IN_DEV_ORCONF(in_dev, NOPOLICY), false);
2337         if (!rth)
2338                 goto e_nobufs;
2339
2340         rth->dst.output= ip_rt_bug;
2341 #ifdef CONFIG_IP_ROUTE_CLASSID
2342         rth->dst.tclassid = itag;
2343 #endif
2344         rth->rt_is_input = 1;
2345
2346         RT_CACHE_STAT_INC(in_slow_tot);
2347         if (res->type == RTN_UNREACHABLE) {
2348                 rth->dst.input= ip_error;
2349                 rth->dst.error= -err;
2350                 rth->rt_flags   &= ~RTCF_LOCAL;
2351         }
2352
2353         if (do_cache) {
2354                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2355
2356                 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2357                 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2358                         WARN_ON(rth->dst.input == lwtunnel_input);
2359                         rth->dst.lwtstate->orig_input = rth->dst.input;
2360                         rth->dst.input = lwtunnel_input;
2361                 }
2362
2363                 if (unlikely(!rt_cache_route(nhc, rth)))
2364                         rt_add_uncached_list(rth);
2365         }
2366         skb_dst_set(skb, &rth->dst);
2367         err = 0;
2368         goto out;
2369
2370 no_route:
2371         RT_CACHE_STAT_INC(in_no_route);
2372         res->type = RTN_UNREACHABLE;
2373         res->fi = NULL;
2374         res->table = NULL;
2375         goto local_input;
2376
2377         /*
2378          *      Do not cache martian addresses: they should be logged (RFC1812)
2379          */
2380 martian_destination:
2381         RT_CACHE_STAT_INC(in_martian_dst);
2382 #ifdef CONFIG_IP_ROUTE_VERBOSE
2383         if (IN_DEV_LOG_MARTIANS(in_dev))
2384                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2385                                      &daddr, &saddr, dev->name);
2386 #endif
2387
2388 e_inval:
2389         err = -EINVAL;
2390         goto out;
2391
2392 e_nobufs:
2393         err = -ENOBUFS;
2394         goto out;
2395
2396 martian_source:
2397         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2398         goto out;
2399 }
2400
2401 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2402                          u8 tos, struct net_device *dev)
2403 {
2404         struct fib_result res;
2405         int err;
2406
2407         tos &= IPTOS_RT_MASK;
2408         rcu_read_lock();
2409         err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2410         rcu_read_unlock();
2411
2412         return err;
2413 }
2414 EXPORT_SYMBOL(ip_route_input_noref);
2415
2416 /* called with rcu_read_lock held */
2417 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2418                        u8 tos, struct net_device *dev, struct fib_result *res)
2419 {
2420         /* Multicast recognition logic is moved from route cache to here.
2421          * The problem was that too many Ethernet cards have broken/missing
2422          * hardware multicast filters :-( As result the host on multicasting
2423          * network acquires a lot of useless route cache entries, sort of
2424          * SDR messages from all the world. Now we try to get rid of them.
2425          * Really, provided software IP multicast filter is organized
2426          * reasonably (at least, hashed), it does not result in a slowdown
2427          * comparing with route cache reject entries.
2428          * Note, that multicast routers are not affected, because
2429          * route cache entry is created eventually.
2430          */
2431         if (ipv4_is_multicast(daddr)) {
2432                 struct in_device *in_dev = __in_dev_get_rcu(dev);
2433                 int our = 0;
2434                 int err = -EINVAL;
2435
2436                 if (!in_dev)
2437                         return err;
2438                 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2439                                       ip_hdr(skb)->protocol);
2440
2441                 /* check l3 master if no match yet */
2442                 if (!our && netif_is_l3_slave(dev)) {
2443                         struct in_device *l3_in_dev;
2444
2445                         l3_in_dev = __in_dev_get_rcu(skb->dev);
2446                         if (l3_in_dev)
2447                                 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2448                                                       ip_hdr(skb)->protocol);
2449                 }
2450
2451                 if (our
2452 #ifdef CONFIG_IP_MROUTE
2453                         ||
2454                     (!ipv4_is_local_multicast(daddr) &&
2455                      IN_DEV_MFORWARD(in_dev))
2456 #endif
2457                    ) {
2458                         err = ip_route_input_mc(skb, daddr, saddr,
2459                                                 tos, dev, our);
2460                 }
2461                 return err;
2462         }
2463
2464         return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2465 }
2466
2467 /* called with rcu_read_lock() */
2468 static struct rtable *__mkroute_output(const struct fib_result *res,
2469                                        const struct flowi4 *fl4, int orig_oif,
2470                                        struct net_device *dev_out,
2471                                        unsigned int flags)
2472 {
2473         struct fib_info *fi = res->fi;
2474         struct fib_nh_exception *fnhe;
2475         struct in_device *in_dev;
2476         u16 type = res->type;
2477         struct rtable *rth;
2478         bool do_cache;
2479
2480         in_dev = __in_dev_get_rcu(dev_out);
2481         if (!in_dev)
2482                 return ERR_PTR(-EINVAL);
2483
2484         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2485                 if (ipv4_is_loopback(fl4->saddr) &&
2486                     !(dev_out->flags & IFF_LOOPBACK) &&
2487                     !netif_is_l3_master(dev_out))
2488                         return ERR_PTR(-EINVAL);
2489
2490         if (ipv4_is_lbcast(fl4->daddr))
2491                 type = RTN_BROADCAST;
2492         else if (ipv4_is_multicast(fl4->daddr))
2493                 type = RTN_MULTICAST;
2494         else if (ipv4_is_zeronet(fl4->daddr))
2495                 return ERR_PTR(-EINVAL);
2496
2497         if (dev_out->flags & IFF_LOOPBACK)
2498                 flags |= RTCF_LOCAL;
2499
2500         do_cache = true;
2501         if (type == RTN_BROADCAST) {
2502                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2503                 fi = NULL;
2504         } else if (type == RTN_MULTICAST) {
2505                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2506                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2507                                      fl4->flowi4_proto))
2508                         flags &= ~RTCF_LOCAL;
2509                 else
2510                         do_cache = false;
2511                 /* If multicast route do not exist use
2512                  * default one, but do not gateway in this case.
2513                  * Yes, it is hack.
2514                  */
2515                 if (fi && res->prefixlen < 4)
2516                         fi = NULL;
2517         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2518                    (orig_oif != dev_out->ifindex)) {
2519                 /* For local routes that require a particular output interface
2520                  * we do not want to cache the result.  Caching the result
2521                  * causes incorrect behaviour when there are multiple source
2522                  * addresses on the interface, the end result being that if the
2523                  * intended recipient is waiting on that interface for the
2524                  * packet he won't receive it because it will be delivered on
2525                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2526                  * be set to the loopback interface as well.
2527                  */
2528                 do_cache = false;
2529         }
2530
2531         fnhe = NULL;
2532         do_cache &= fi != NULL;
2533         if (fi) {
2534                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2535                 struct rtable __rcu **prth;
2536
2537                 fnhe = find_exception(nhc, fl4->daddr);
2538                 if (!do_cache)
2539                         goto add;
2540                 if (fnhe) {
2541                         prth = &fnhe->fnhe_rth_output;
2542                 } else {
2543                         if (unlikely(fl4->flowi4_flags &
2544                                      FLOWI_FLAG_KNOWN_NH &&
2545                                      !(nhc->nhc_gw_family &&
2546                                        nhc->nhc_scope == RT_SCOPE_LINK))) {
2547                                 do_cache = false;
2548                                 goto add;
2549                         }
2550                         prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2551                 }
2552                 rth = rcu_dereference(*prth);
2553                 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2554                         return rth;
2555         }
2556
2557 add:
2558         rth = rt_dst_alloc(dev_out, flags, type,
2559                            IN_DEV_ORCONF(in_dev, NOPOLICY),
2560                            IN_DEV_ORCONF(in_dev, NOXFRM));
2561         if (!rth)
2562                 return ERR_PTR(-ENOBUFS);
2563
2564         rth->rt_iif = orig_oif;
2565
2566         RT_CACHE_STAT_INC(out_slow_tot);
2567
2568         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2569                 if (flags & RTCF_LOCAL &&
2570                     !(dev_out->flags & IFF_LOOPBACK)) {
2571                         rth->dst.output = ip_mc_output;
2572                         RT_CACHE_STAT_INC(out_slow_mc);
2573                 }
2574 #ifdef CONFIG_IP_MROUTE
2575                 if (type == RTN_MULTICAST) {
2576                         if (IN_DEV_MFORWARD(in_dev) &&
2577                             !ipv4_is_local_multicast(fl4->daddr)) {
2578                                 rth->dst.input = ip_mr_input;
2579                                 rth->dst.output = ip_mc_output;
2580                         }
2581                 }
2582 #endif
2583         }
2584
2585         rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2586         lwtunnel_set_redirect(&rth->dst);
2587
2588         return rth;
2589 }
2590
2591 /*
2592  * Major route resolver routine.
2593  */
2594
2595 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2596                                         const struct sk_buff *skb)
2597 {
2598         __u8 tos = RT_FL_TOS(fl4);
2599         struct fib_result res = {
2600                 .type           = RTN_UNSPEC,
2601                 .fi             = NULL,
2602                 .table          = NULL,
2603                 .tclassid       = 0,
2604         };
2605         struct rtable *rth;
2606
2607         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2608         fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2609         fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2610                          RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2611
2612         rcu_read_lock();
2613         rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2614         rcu_read_unlock();
2615
2616         return rth;
2617 }
2618 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2619
2620 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2621                                             struct fib_result *res,
2622                                             const struct sk_buff *skb)
2623 {
2624         struct net_device *dev_out = NULL;
2625         int orig_oif = fl4->flowi4_oif;
2626         unsigned int flags = 0;
2627         struct rtable *rth;
2628         int err;
2629
2630         if (fl4->saddr) {
2631                 if (ipv4_is_multicast(fl4->saddr) ||
2632                     ipv4_is_lbcast(fl4->saddr) ||
2633                     ipv4_is_zeronet(fl4->saddr)) {
2634                         rth = ERR_PTR(-EINVAL);
2635                         goto out;
2636                 }
2637
2638                 rth = ERR_PTR(-ENETUNREACH);
2639
2640                 /* I removed check for oif == dev_out->oif here.
2641                  * It was wrong for two reasons:
2642                  * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2643                  *    is assigned to multiple interfaces.
2644                  * 2. Moreover, we are allowed to send packets with saddr
2645                  *    of another iface. --ANK
2646                  */
2647
2648                 if (fl4->flowi4_oif == 0 &&
2649                     (ipv4_is_multicast(fl4->daddr) ||
2650                      ipv4_is_lbcast(fl4->daddr))) {
2651                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2652                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2653                         if (!dev_out)
2654                                 goto out;
2655
2656                         /* Special hack: user can direct multicasts
2657                          * and limited broadcast via necessary interface
2658                          * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2659                          * This hack is not just for fun, it allows
2660                          * vic,vat and friends to work.
2661                          * They bind socket to loopback, set ttl to zero
2662                          * and expect that it will work.
2663                          * From the viewpoint of routing cache they are broken,
2664                          * because we are not allowed to build multicast path
2665                          * with loopback source addr (look, routing cache
2666                          * cannot know, that ttl is zero, so that packet
2667                          * will not leave this host and route is valid).
2668                          * Luckily, this hack is good workaround.
2669                          */
2670
2671                         fl4->flowi4_oif = dev_out->ifindex;
2672                         goto make_route;
2673                 }
2674
2675                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2676                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2677                         if (!__ip_dev_find(net, fl4->saddr, false))
2678                                 goto out;
2679                 }
2680         }
2681
2682
2683         if (fl4->flowi4_oif) {
2684                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2685                 rth = ERR_PTR(-ENODEV);
2686                 if (!dev_out)
2687                         goto out;
2688
2689                 /* RACE: Check return value of inet_select_addr instead. */
2690                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2691                         rth = ERR_PTR(-ENETUNREACH);
2692                         goto out;
2693                 }
2694                 if (ipv4_is_local_multicast(fl4->daddr) ||
2695                     ipv4_is_lbcast(fl4->daddr) ||
2696                     fl4->flowi4_proto == IPPROTO_IGMP) {
2697                         if (!fl4->saddr)
2698                                 fl4->saddr = inet_select_addr(dev_out, 0,
2699                                                               RT_SCOPE_LINK);
2700                         goto make_route;
2701                 }
2702                 if (!fl4->saddr) {
2703                         if (ipv4_is_multicast(fl4->daddr))
2704                                 fl4->saddr = inet_select_addr(dev_out, 0,
2705                                                               fl4->flowi4_scope);
2706                         else if (!fl4->daddr)
2707                                 fl4->saddr = inet_select_addr(dev_out, 0,
2708                                                               RT_SCOPE_HOST);
2709                 }
2710         }
2711
2712         if (!fl4->daddr) {
2713                 fl4->daddr = fl4->saddr;
2714                 if (!fl4->daddr)
2715                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2716                 dev_out = net->loopback_dev;
2717                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2718                 res->type = RTN_LOCAL;
2719                 flags |= RTCF_LOCAL;
2720                 goto make_route;
2721         }
2722
2723         err = fib_lookup(net, fl4, res, 0);
2724         if (err) {
2725                 res->fi = NULL;
2726                 res->table = NULL;
2727                 if (fl4->flowi4_oif &&
2728                     (ipv4_is_multicast(fl4->daddr) ||
2729                     !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2730                         /* Apparently, routing tables are wrong. Assume,
2731                          * that the destination is on link.
2732                          *
2733                          * WHY? DW.
2734                          * Because we are allowed to send to iface
2735                          * even if it has NO routes and NO assigned
2736                          * addresses. When oif is specified, routing
2737                          * tables are looked up with only one purpose:
2738                          * to catch if destination is gatewayed, rather than
2739                          * direct. Moreover, if MSG_DONTROUTE is set,
2740                          * we send packet, ignoring both routing tables
2741                          * and ifaddr state. --ANK
2742                          *
2743                          *
2744                          * We could make it even if oif is unknown,
2745                          * likely IPv6, but we do not.
2746                          */
2747
2748                         if (fl4->saddr == 0)
2749                                 fl4->saddr = inet_select_addr(dev_out, 0,
2750                                                               RT_SCOPE_LINK);
2751                         res->type = RTN_UNICAST;
2752                         goto make_route;
2753                 }
2754                 rth = ERR_PTR(err);
2755                 goto out;
2756         }
2757
2758         if (res->type == RTN_LOCAL) {
2759                 if (!fl4->saddr) {
2760                         if (res->fi->fib_prefsrc)
2761                                 fl4->saddr = res->fi->fib_prefsrc;
2762                         else
2763                                 fl4->saddr = fl4->daddr;
2764                 }
2765
2766                 /* L3 master device is the loopback for that domain */
2767                 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2768                         net->loopback_dev;
2769
2770                 /* make sure orig_oif points to fib result device even
2771                  * though packet rx/tx happens over loopback or l3mdev
2772                  */
2773                 orig_oif = FIB_RES_OIF(*res);
2774
2775                 fl4->flowi4_oif = dev_out->ifindex;
2776                 flags |= RTCF_LOCAL;
2777                 goto make_route;
2778         }
2779
2780         fib_select_path(net, res, fl4, skb);
2781
2782         dev_out = FIB_RES_DEV(*res);
2783
2784 make_route:
2785         rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2786
2787 out:
2788         return rth;
2789 }
2790
2791 static struct dst_ops ipv4_dst_blackhole_ops = {
2792         .family                 = AF_INET,
2793         .default_advmss         = ipv4_default_advmss,
2794         .neigh_lookup           = ipv4_neigh_lookup,
2795         .check                  = dst_blackhole_check,
2796         .cow_metrics            = dst_blackhole_cow_metrics,
2797         .update_pmtu            = dst_blackhole_update_pmtu,
2798         .redirect               = dst_blackhole_redirect,
2799         .mtu                    = dst_blackhole_mtu,
2800 };
2801
2802 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2803 {
2804         struct rtable *ort = (struct rtable *) dst_orig;
2805         struct rtable *rt;
2806
2807         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2808         if (rt) {
2809                 struct dst_entry *new = &rt->dst;
2810
2811                 new->__use = 1;
2812                 new->input = dst_discard;
2813                 new->output = dst_discard_out;
2814
2815                 new->dev = net->loopback_dev;
2816                 dev_hold(new->dev);
2817
2818                 rt->rt_is_input = ort->rt_is_input;
2819                 rt->rt_iif = ort->rt_iif;
2820                 rt->rt_pmtu = ort->rt_pmtu;
2821                 rt->rt_mtu_locked = ort->rt_mtu_locked;
2822
2823                 rt->rt_genid = rt_genid_ipv4(net);
2824                 rt->rt_flags = ort->rt_flags;
2825                 rt->rt_type = ort->rt_type;
2826                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2827                 rt->rt_gw_family = ort->rt_gw_family;
2828                 if (rt->rt_gw_family == AF_INET)
2829                         rt->rt_gw4 = ort->rt_gw4;
2830                 else if (rt->rt_gw_family == AF_INET6)
2831                         rt->rt_gw6 = ort->rt_gw6;
2832
2833                 INIT_LIST_HEAD(&rt->rt_uncached);
2834         }
2835
2836         dst_release(dst_orig);
2837
2838         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2839 }
2840
2841 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2842                                     const struct sock *sk)
2843 {
2844         struct rtable *rt = __ip_route_output_key(net, flp4);
2845
2846         if (IS_ERR(rt))
2847                 return rt;
2848
2849         if (flp4->flowi4_proto) {
2850                 flp4->flowi4_oif = rt->dst.dev->ifindex;
2851                 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2852                                                         flowi4_to_flowi(flp4),
2853                                                         sk, 0);
2854         }
2855
2856         return rt;
2857 }
2858 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2859
2860 struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
2861                                       struct net_device *dev,
2862                                       struct net *net, __be32 *saddr,
2863                                       const struct ip_tunnel_info *info,
2864                                       u8 protocol, bool use_cache)
2865 {
2866 #ifdef CONFIG_DST_CACHE
2867         struct dst_cache *dst_cache;
2868 #endif
2869         struct rtable *rt = NULL;
2870         struct flowi4 fl4;
2871         __u8 tos;
2872
2873 #ifdef CONFIG_DST_CACHE
2874         dst_cache = (struct dst_cache *)&info->dst_cache;
2875         if (use_cache) {
2876                 rt = dst_cache_get_ip4(dst_cache, saddr);
2877                 if (rt)
2878                         return rt;
2879         }
2880 #endif
2881         memset(&fl4, 0, sizeof(fl4));
2882         fl4.flowi4_mark = skb->mark;
2883         fl4.flowi4_proto = protocol;
2884         fl4.daddr = info->key.u.ipv4.dst;
2885         fl4.saddr = info->key.u.ipv4.src;
2886         tos = info->key.tos;
2887         fl4.flowi4_tos = RT_TOS(tos);
2888
2889         rt = ip_route_output_key(net, &fl4);
2890         if (IS_ERR(rt)) {
2891                 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
2892                 return ERR_PTR(-ENETUNREACH);
2893         }
2894         if (rt->dst.dev == dev) { /* is this necessary? */
2895                 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
2896                 ip_rt_put(rt);
2897                 return ERR_PTR(-ELOOP);
2898         }
2899 #ifdef CONFIG_DST_CACHE
2900         if (use_cache)
2901                 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
2902 #endif
2903         *saddr = fl4.saddr;
2904         return rt;
2905 }
2906 EXPORT_SYMBOL_GPL(ip_route_output_tunnel);
2907
2908 /* called with rcu_read_lock held */
2909 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2910                         struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2911                         struct sk_buff *skb, u32 portid, u32 seq,
2912                         unsigned int flags)
2913 {
2914         struct rtmsg *r;
2915         struct nlmsghdr *nlh;
2916         unsigned long expires = 0;
2917         u32 error;
2918         u32 metrics[RTAX_MAX];
2919
2920         nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2921         if (!nlh)
2922                 return -EMSGSIZE;
2923
2924         r = nlmsg_data(nlh);
2925         r->rtm_family    = AF_INET;
2926         r->rtm_dst_len  = 32;
2927         r->rtm_src_len  = 0;
2928         r->rtm_tos      = fl4 ? fl4->flowi4_tos : 0;
2929         r->rtm_table    = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2930         if (nla_put_u32(skb, RTA_TABLE, table_id))
2931                 goto nla_put_failure;
2932         r->rtm_type     = rt->rt_type;
2933         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2934         r->rtm_protocol = RTPROT_UNSPEC;
2935         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2936         if (rt->rt_flags & RTCF_NOTIFY)
2937                 r->rtm_flags |= RTM_F_NOTIFY;
2938         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2939                 r->rtm_flags |= RTCF_DOREDIRECT;
2940
2941         if (nla_put_in_addr(skb, RTA_DST, dst))
2942                 goto nla_put_failure;
2943         if (src) {
2944                 r->rtm_src_len = 32;
2945                 if (nla_put_in_addr(skb, RTA_SRC, src))
2946                         goto nla_put_failure;
2947         }
2948         if (rt->dst.dev &&
2949             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2950                 goto nla_put_failure;
2951         if (rt->dst.lwtstate &&
2952             lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2953                 goto nla_put_failure;
2954 #ifdef CONFIG_IP_ROUTE_CLASSID
2955         if (rt->dst.tclassid &&
2956             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2957                 goto nla_put_failure;
2958 #endif
2959         if (fl4 && !rt_is_input_route(rt) &&
2960             fl4->saddr != src) {
2961                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2962                         goto nla_put_failure;
2963         }
2964         if (rt->rt_uses_gateway) {
2965                 if (rt->rt_gw_family == AF_INET &&
2966                     nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2967                         goto nla_put_failure;
2968                 } else if (rt->rt_gw_family == AF_INET6) {
2969                         int alen = sizeof(struct in6_addr);
2970                         struct nlattr *nla;
2971                         struct rtvia *via;
2972
2973                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
2974                         if (!nla)
2975                                 goto nla_put_failure;
2976
2977                         via = nla_data(nla);
2978                         via->rtvia_family = AF_INET6;
2979                         memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2980                 }
2981         }
2982
2983         expires = rt->dst.expires;
2984         if (expires) {
2985                 unsigned long now = jiffies;
2986
2987                 if (time_before(now, expires))
2988                         expires -= now;
2989                 else
2990                         expires = 0;
2991         }
2992
2993         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2994         if (rt->rt_pmtu && expires)
2995                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2996         if (rt->rt_mtu_locked && expires)
2997                 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2998         if (rtnetlink_put_metrics(skb, metrics) < 0)
2999                 goto nla_put_failure;
3000
3001         if (fl4) {
3002                 if (fl4->flowi4_mark &&
3003                     nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
3004                         goto nla_put_failure;
3005
3006                 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
3007                     nla_put_u32(skb, RTA_UID,
3008                                 from_kuid_munged(current_user_ns(),
3009                                                  fl4->flowi4_uid)))
3010                         goto nla_put_failure;
3011
3012                 if (rt_is_input_route(rt)) {
3013 #ifdef CONFIG_IP_MROUTE
3014                         if (ipv4_is_multicast(dst) &&
3015                             !ipv4_is_local_multicast(dst) &&
3016                             IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3017                                 int err = ipmr_get_route(net, skb,
3018                                                          fl4->saddr, fl4->daddr,
3019                                                          r, portid);
3020
3021                                 if (err <= 0) {
3022                                         if (err == 0)
3023                                                 return 0;
3024                                         goto nla_put_failure;
3025                                 }
3026                         } else
3027 #endif
3028                                 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3029                                         goto nla_put_failure;
3030                 }
3031         }
3032
3033         error = rt->dst.error;
3034
3035         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3036                 goto nla_put_failure;
3037
3038         nlmsg_end(skb, nlh);
3039         return 0;
3040
3041 nla_put_failure:
3042         nlmsg_cancel(skb, nlh);
3043         return -EMSGSIZE;
3044 }
3045
3046 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3047                             struct netlink_callback *cb, u32 table_id,
3048                             struct fnhe_hash_bucket *bucket, int genid,
3049                             int *fa_index, int fa_start, unsigned int flags)
3050 {
3051         int i;
3052
3053         for (i = 0; i < FNHE_HASH_SIZE; i++) {
3054                 struct fib_nh_exception *fnhe;
3055
3056                 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3057                      fnhe = rcu_dereference(fnhe->fnhe_next)) {
3058                         struct rtable *rt;
3059                         int err;
3060
3061                         if (*fa_index < fa_start)
3062                                 goto next;
3063
3064                         if (fnhe->fnhe_genid != genid)
3065                                 goto next;
3066
3067                         if (fnhe->fnhe_expires &&
3068                             time_after(jiffies, fnhe->fnhe_expires))
3069                                 goto next;
3070
3071                         rt = rcu_dereference(fnhe->fnhe_rth_input);
3072                         if (!rt)
3073                                 rt = rcu_dereference(fnhe->fnhe_rth_output);
3074                         if (!rt)
3075                                 goto next;
3076
3077                         err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3078                                            table_id, NULL, skb,
3079                                            NETLINK_CB(cb->skb).portid,
3080                                            cb->nlh->nlmsg_seq, flags);
3081                         if (err)
3082                                 return err;
3083 next:
3084                         (*fa_index)++;
3085                 }
3086         }
3087
3088         return 0;
3089 }
3090
3091 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3092                        u32 table_id, struct fib_info *fi,
3093                        int *fa_index, int fa_start, unsigned int flags)
3094 {
3095         struct net *net = sock_net(cb->skb->sk);
3096         int nhsel, genid = fnhe_genid(net);
3097
3098         for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3099                 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3100                 struct fnhe_hash_bucket *bucket;
3101                 int err;
3102
3103                 if (nhc->nhc_flags & RTNH_F_DEAD)
3104                         continue;
3105
3106                 rcu_read_lock();
3107                 bucket = rcu_dereference(nhc->nhc_exceptions);
3108                 err = 0;
3109                 if (bucket)
3110                         err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3111                                                genid, fa_index, fa_start,
3112                                                flags);
3113                 rcu_read_unlock();
3114                 if (err)
3115                         return err;
3116         }
3117
3118         return 0;
3119 }
3120
3121 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3122                                                    u8 ip_proto, __be16 sport,
3123                                                    __be16 dport)
3124 {
3125         struct sk_buff *skb;
3126         struct iphdr *iph;
3127
3128         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3129         if (!skb)
3130                 return NULL;
3131
3132         /* Reserve room for dummy headers, this skb can pass
3133          * through good chunk of routing engine.
3134          */
3135         skb_reset_mac_header(skb);
3136         skb_reset_network_header(skb);
3137         skb->protocol = htons(ETH_P_IP);
3138         iph = skb_put(skb, sizeof(struct iphdr));
3139         iph->protocol = ip_proto;
3140         iph->saddr = src;
3141         iph->daddr = dst;
3142         iph->version = 0x4;
3143         iph->frag_off = 0;
3144         iph->ihl = 0x5;
3145         skb_set_transport_header(skb, skb->len);
3146
3147         switch (iph->protocol) {
3148         case IPPROTO_UDP: {
3149                 struct udphdr *udph;
3150
3151                 udph = skb_put_zero(skb, sizeof(struct udphdr));
3152                 udph->source = sport;
3153                 udph->dest = dport;
3154                 udph->len = sizeof(struct udphdr);
3155                 udph->check = 0;
3156                 break;
3157         }
3158         case IPPROTO_TCP: {
3159                 struct tcphdr *tcph;
3160
3161                 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3162                 tcph->source    = sport;
3163                 tcph->dest      = dport;
3164                 tcph->doff      = sizeof(struct tcphdr) / 4;
3165                 tcph->rst = 1;
3166                 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3167                                             src, dst, 0);
3168                 break;
3169         }
3170         case IPPROTO_ICMP: {
3171                 struct icmphdr *icmph;
3172
3173                 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3174                 icmph->type = ICMP_ECHO;
3175                 icmph->code = 0;
3176         }
3177         }
3178
3179         return skb;
3180 }
3181
3182 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3183                                        const struct nlmsghdr *nlh,
3184                                        struct nlattr **tb,
3185                                        struct netlink_ext_ack *extack)
3186 {
3187         struct rtmsg *rtm;
3188         int i, err;
3189
3190         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3191                 NL_SET_ERR_MSG(extack,
3192                                "ipv4: Invalid header for route get request");
3193                 return -EINVAL;
3194         }
3195
3196         if (!netlink_strict_get_check(skb))
3197                 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3198                                               rtm_ipv4_policy, extack);
3199
3200         rtm = nlmsg_data(nlh);
3201         if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3202             (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3203             rtm->rtm_table || rtm->rtm_protocol ||
3204             rtm->rtm_scope || rtm->rtm_type) {
3205                 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3206                 return -EINVAL;
3207         }
3208
3209         if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3210                                RTM_F_LOOKUP_TABLE |
3211                                RTM_F_FIB_MATCH)) {
3212                 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3213                 return -EINVAL;
3214         }
3215
3216         err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3217                                             rtm_ipv4_policy, extack);
3218         if (err)
3219                 return err;
3220
3221         if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3222             (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3223                 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3224                 return -EINVAL;
3225         }
3226
3227         for (i = 0; i <= RTA_MAX; i++) {
3228                 if (!tb[i])
3229                         continue;
3230
3231                 switch (i) {
3232                 case RTA_IIF:
3233                 case RTA_OIF:
3234                 case RTA_SRC:
3235                 case RTA_DST:
3236                 case RTA_IP_PROTO:
3237                 case RTA_SPORT:
3238                 case RTA_DPORT:
3239                 case RTA_MARK:
3240                 case RTA_UID:
3241                         break;
3242                 default:
3243                         NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3244                         return -EINVAL;
3245                 }
3246         }
3247
3248         return 0;
3249 }
3250
3251 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3252                              struct netlink_ext_ack *extack)
3253 {
3254         struct net *net = sock_net(in_skb->sk);
3255         struct nlattr *tb[RTA_MAX+1];
3256         u32 table_id = RT_TABLE_MAIN;
3257         __be16 sport = 0, dport = 0;
3258         struct fib_result res = {};
3259         u8 ip_proto = IPPROTO_UDP;
3260         struct rtable *rt = NULL;
3261         struct sk_buff *skb;
3262         struct rtmsg *rtm;
3263         struct flowi4 fl4 = {};
3264         __be32 dst = 0;
3265         __be32 src = 0;
3266         kuid_t uid;
3267         u32 iif;
3268         int err;
3269         int mark;
3270
3271         err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3272         if (err < 0)
3273                 return err;
3274
3275         rtm = nlmsg_data(nlh);
3276         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3277         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3278         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3279         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3280         if (tb[RTA_UID])
3281                 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3282         else
3283                 uid = (iif ? INVALID_UID : current_uid());
3284
3285         if (tb[RTA_IP_PROTO]) {
3286                 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3287                                                   &ip_proto, AF_INET, extack);
3288                 if (err)
3289                         return err;
3290         }
3291
3292         if (tb[RTA_SPORT])
3293                 sport = nla_get_be16(tb[RTA_SPORT]);
3294
3295         if (tb[RTA_DPORT])
3296                 dport = nla_get_be16(tb[RTA_DPORT]);
3297
3298         skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3299         if (!skb)
3300                 return -ENOBUFS;
3301
3302         fl4.daddr = dst;
3303         fl4.saddr = src;
3304         fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3305         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3306         fl4.flowi4_mark = mark;
3307         fl4.flowi4_uid = uid;
3308         if (sport)
3309                 fl4.fl4_sport = sport;
3310         if (dport)
3311                 fl4.fl4_dport = dport;
3312         fl4.flowi4_proto = ip_proto;
3313
3314         rcu_read_lock();
3315
3316         if (iif) {
3317                 struct net_device *dev;
3318
3319                 dev = dev_get_by_index_rcu(net, iif);
3320                 if (!dev) {
3321                         err = -ENODEV;
3322                         goto errout_rcu;
3323                 }
3324
3325                 fl4.flowi4_iif = iif; /* for rt_fill_info */
3326                 skb->dev        = dev;
3327                 skb->mark       = mark;
3328                 err = ip_route_input_rcu(skb, dst, src,
3329                                          rtm->rtm_tos & IPTOS_RT_MASK, dev,
3330                                          &res);
3331
3332                 rt = skb_rtable(skb);
3333                 if (err == 0 && rt->dst.error)
3334                         err = -rt->dst.error;
3335         } else {
3336                 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3337                 skb->dev = net->loopback_dev;
3338                 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3339                 err = 0;
3340                 if (IS_ERR(rt))
3341                         err = PTR_ERR(rt);
3342                 else
3343                         skb_dst_set(skb, &rt->dst);
3344         }
3345
3346         if (err)
3347                 goto errout_rcu;
3348
3349         if (rtm->rtm_flags & RTM_F_NOTIFY)
3350                 rt->rt_flags |= RTCF_NOTIFY;
3351
3352         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3353                 table_id = res.table ? res.table->tb_id : 0;
3354
3355         /* reset skb for netlink reply msg */
3356         skb_trim(skb, 0);
3357         skb_reset_network_header(skb);
3358         skb_reset_transport_header(skb);
3359         skb_reset_mac_header(skb);
3360
3361         if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3362                 struct fib_rt_info fri;
3363
3364                 if (!res.fi) {
3365                         err = fib_props[res.type].error;
3366                         if (!err)
3367                                 err = -EHOSTUNREACH;
3368                         goto errout_rcu;
3369                 }
3370                 fri.fi = res.fi;
3371                 fri.tb_id = table_id;
3372                 fri.dst = res.prefix;
3373                 fri.dst_len = res.prefixlen;
3374                 fri.tos = fl4.flowi4_tos;
3375                 fri.type = rt->rt_type;
3376                 fri.offload = 0;
3377                 fri.trap = 0;
3378                 fri.offload_failed = 0;
3379                 if (res.fa_head) {
3380                         struct fib_alias *fa;
3381
3382                         hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3383                                 u8 slen = 32 - fri.dst_len;
3384
3385                                 if (fa->fa_slen == slen &&
3386                                     fa->tb_id == fri.tb_id &&
3387                                     fa->fa_tos == fri.tos &&
3388                                     fa->fa_info == res.fi &&
3389                                     fa->fa_type == fri.type) {
3390                                         fri.offload = fa->offload;
3391                                         fri.trap = fa->trap;
3392                                         break;
3393                                 }
3394                         }
3395                 }
3396                 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3397                                     nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3398         } else {
3399                 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3400                                    NETLINK_CB(in_skb).portid,
3401                                    nlh->nlmsg_seq, 0);
3402         }
3403         if (err < 0)
3404                 goto errout_rcu;
3405
3406         rcu_read_unlock();
3407
3408         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3409
3410 errout_free:
3411         return err;
3412 errout_rcu:
3413         rcu_read_unlock();
3414         kfree_skb(skb);
3415         goto errout_free;
3416 }
3417
3418 void ip_rt_multicast_event(struct in_device *in_dev)
3419 {
3420         rt_cache_flush(dev_net(in_dev->dev));
3421 }
3422
3423 #ifdef CONFIG_SYSCTL
3424 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
3425 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
3426 static int ip_rt_gc_elasticity __read_mostly    = 8;
3427 static int ip_min_valid_pmtu __read_mostly      = IPV4_MIN_MTU;
3428
3429 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3430                 void *buffer, size_t *lenp, loff_t *ppos)
3431 {
3432         struct net *net = (struct net *)__ctl->extra1;
3433
3434         if (write) {
3435                 rt_cache_flush(net);
3436                 fnhe_genid_bump(net);
3437                 return 0;
3438         }
3439
3440         return -EINVAL;
3441 }
3442
3443 static struct ctl_table ipv4_route_table[] = {
3444         {
3445                 .procname       = "gc_thresh",
3446                 .data           = &ipv4_dst_ops.gc_thresh,
3447                 .maxlen         = sizeof(int),
3448                 .mode           = 0644,
3449                 .proc_handler   = proc_dointvec,
3450         },
3451         {
3452                 .procname       = "max_size",
3453                 .data           = &ip_rt_max_size,
3454                 .maxlen         = sizeof(int),
3455                 .mode           = 0644,
3456                 .proc_handler   = proc_dointvec,
3457         },
3458         {
3459                 /*  Deprecated. Use gc_min_interval_ms */
3460
3461                 .procname       = "gc_min_interval",
3462                 .data           = &ip_rt_gc_min_interval,
3463                 .maxlen         = sizeof(int),
3464                 .mode           = 0644,
3465                 .proc_handler   = proc_dointvec_jiffies,
3466         },
3467         {
3468                 .procname       = "gc_min_interval_ms",
3469                 .data           = &ip_rt_gc_min_interval,
3470                 .maxlen         = sizeof(int),
3471                 .mode           = 0644,
3472                 .proc_handler   = proc_dointvec_ms_jiffies,
3473         },
3474         {
3475                 .procname       = "gc_timeout",
3476                 .data           = &ip_rt_gc_timeout,
3477                 .maxlen         = sizeof(int),
3478                 .mode           = 0644,
3479                 .proc_handler   = proc_dointvec_jiffies,
3480         },
3481         {
3482                 .procname       = "gc_interval",
3483                 .data           = &ip_rt_gc_interval,
3484                 .maxlen         = sizeof(int),
3485                 .mode           = 0644,
3486                 .proc_handler   = proc_dointvec_jiffies,
3487         },
3488         {
3489                 .procname       = "redirect_load",
3490                 .data           = &ip_rt_redirect_load,
3491                 .maxlen         = sizeof(int),
3492                 .mode           = 0644,
3493                 .proc_handler   = proc_dointvec,
3494         },
3495         {
3496                 .procname       = "redirect_number",
3497                 .data           = &ip_rt_redirect_number,
3498                 .maxlen         = sizeof(int),
3499                 .mode           = 0644,
3500                 .proc_handler   = proc_dointvec,
3501         },
3502         {
3503                 .procname       = "redirect_silence",
3504                 .data           = &ip_rt_redirect_silence,
3505                 .maxlen         = sizeof(int),
3506                 .mode           = 0644,
3507                 .proc_handler   = proc_dointvec,
3508         },
3509         {
3510                 .procname       = "error_cost",
3511                 .data           = &ip_rt_error_cost,
3512                 .maxlen         = sizeof(int),
3513                 .mode           = 0644,
3514                 .proc_handler   = proc_dointvec,
3515         },
3516         {
3517                 .procname       = "error_burst",
3518                 .data           = &ip_rt_error_burst,
3519                 .maxlen         = sizeof(int),
3520                 .mode           = 0644,
3521                 .proc_handler   = proc_dointvec,
3522         },
3523         {
3524                 .procname       = "gc_elasticity",
3525                 .data           = &ip_rt_gc_elasticity,
3526                 .maxlen         = sizeof(int),
3527                 .mode           = 0644,
3528                 .proc_handler   = proc_dointvec,
3529         },
3530         {
3531                 .procname       = "mtu_expires",
3532                 .data           = &ip_rt_mtu_expires,
3533                 .maxlen         = sizeof(int),
3534                 .mode           = 0644,
3535                 .proc_handler   = proc_dointvec_jiffies,
3536         },
3537         {
3538                 .procname       = "min_pmtu",
3539                 .data           = &ip_rt_min_pmtu,
3540                 .maxlen         = sizeof(int),
3541                 .mode           = 0644,
3542                 .proc_handler   = proc_dointvec_minmax,
3543                 .extra1         = &ip_min_valid_pmtu,
3544         },
3545         {
3546                 .procname       = "min_adv_mss",
3547                 .data           = &ip_rt_min_advmss,
3548                 .maxlen         = sizeof(int),
3549                 .mode           = 0644,
3550                 .proc_handler   = proc_dointvec,
3551         },
3552         { }
3553 };
3554
3555 static const char ipv4_route_flush_procname[] = "flush";
3556
3557 static struct ctl_table ipv4_route_flush_table[] = {
3558         {
3559                 .procname       = ipv4_route_flush_procname,
3560                 .maxlen         = sizeof(int),
3561                 .mode           = 0200,
3562                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3563         },
3564         { },
3565 };
3566
3567 static __net_init int sysctl_route_net_init(struct net *net)
3568 {
3569         struct ctl_table *tbl;
3570
3571         tbl = ipv4_route_flush_table;
3572         if (!net_eq(net, &init_net)) {
3573                 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3574                 if (!tbl)
3575                         goto err_dup;
3576
3577                 /* Don't export non-whitelisted sysctls to unprivileged users */
3578                 if (net->user_ns != &init_user_ns) {
3579                         if (tbl[0].procname != ipv4_route_flush_procname)
3580                                 tbl[0].procname = NULL;
3581                 }
3582         }
3583         tbl[0].extra1 = net;
3584
3585         net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3586         if (!net->ipv4.route_hdr)
3587                 goto err_reg;
3588         return 0;
3589
3590 err_reg:
3591         if (tbl != ipv4_route_flush_table)
3592                 kfree(tbl);
3593 err_dup:
3594         return -ENOMEM;
3595 }
3596
3597 static __net_exit void sysctl_route_net_exit(struct net *net)
3598 {
3599         struct ctl_table *tbl;
3600
3601         tbl = net->ipv4.route_hdr->ctl_table_arg;
3602         unregister_net_sysctl_table(net->ipv4.route_hdr);
3603         BUG_ON(tbl == ipv4_route_flush_table);
3604         kfree(tbl);
3605 }
3606
3607 static __net_initdata struct pernet_operations sysctl_route_ops = {
3608         .init = sysctl_route_net_init,
3609         .exit = sysctl_route_net_exit,
3610 };
3611 #endif
3612
3613 static __net_init int rt_genid_init(struct net *net)
3614 {
3615         atomic_set(&net->ipv4.rt_genid, 0);
3616         atomic_set(&net->fnhe_genid, 0);
3617         atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3618         return 0;
3619 }
3620
3621 static __net_initdata struct pernet_operations rt_genid_ops = {
3622         .init = rt_genid_init,
3623 };
3624
3625 static int __net_init ipv4_inetpeer_init(struct net *net)
3626 {
3627         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3628
3629         if (!bp)
3630                 return -ENOMEM;
3631         inet_peer_base_init(bp);
3632         net->ipv4.peers = bp;
3633         return 0;
3634 }
3635
3636 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3637 {
3638         struct inet_peer_base *bp = net->ipv4.peers;
3639
3640         net->ipv4.peers = NULL;
3641         inetpeer_invalidate_tree(bp);
3642         kfree(bp);
3643 }
3644
3645 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3646         .init   =       ipv4_inetpeer_init,
3647         .exit   =       ipv4_inetpeer_exit,
3648 };
3649
3650 #ifdef CONFIG_IP_ROUTE_CLASSID
3651 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3652 #endif /* CONFIG_IP_ROUTE_CLASSID */
3653
3654 int __init ip_rt_init(void)
3655 {
3656         void *idents_hash;
3657         int cpu;
3658
3659         /* For modern hosts, this will use 2 MB of memory */
3660         idents_hash = alloc_large_system_hash("IP idents",
3661                                               sizeof(*ip_idents) + sizeof(*ip_tstamps),
3662                                               0,
3663                                               16, /* one bucket per 64 KB */
3664                                               HASH_ZERO,
3665                                               NULL,
3666                                               &ip_idents_mask,
3667                                               2048,
3668                                               256*1024);
3669
3670         ip_idents = idents_hash;
3671
3672         prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3673
3674         ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3675
3676         for_each_possible_cpu(cpu) {
3677                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3678
3679                 INIT_LIST_HEAD(&ul->head);
3680                 spin_lock_init(&ul->lock);
3681         }
3682 #ifdef CONFIG_IP_ROUTE_CLASSID
3683         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3684         if (!ip_rt_acct)
3685                 panic("IP: failed to allocate ip_rt_acct\n");
3686 #endif
3687
3688         ipv4_dst_ops.kmem_cachep =
3689                 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3690                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3691
3692         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3693
3694         if (dst_entries_init(&ipv4_dst_ops) < 0)
3695                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3696
3697         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3698                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3699
3700         ipv4_dst_ops.gc_thresh = ~0;
3701         ip_rt_max_size = INT_MAX;
3702
3703         devinet_init();
3704         ip_fib_init();
3705
3706         if (ip_rt_proc_init())
3707                 pr_err("Unable to create route proc files\n");
3708 #ifdef CONFIG_XFRM
3709         xfrm_init();
3710         xfrm4_init();
3711 #endif
3712         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3713                       RTNL_FLAG_DOIT_UNLOCKED);
3714
3715 #ifdef CONFIG_SYSCTL
3716         register_pernet_subsys(&sysctl_route_ops);
3717 #endif
3718         register_pernet_subsys(&rt_genid_ops);
3719         register_pernet_subsys(&ipv4_inetpeer_ops);
3720         return 0;
3721 }
3722
3723 #ifdef CONFIG_SYSCTL
3724 /*
3725  * We really need to sanitize the damn ipv4 init order, then all
3726  * this nonsense will go away.
3727  */
3728 void __init ip_static_sysctl_init(void)
3729 {
3730         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3731 }
3732 #endif