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/bitops.h>
  65 #include <linux/kernel.h>
  66 #include <linux/mm.h>
  67 #include <linux/memblock.h>
  68 #include <linux/socket.h>
  69 #include <linux/errno.h>
  70 #include <linux/in.h>
  71 #include <linux/inet.h>
  72 #include <linux/netdevice.h>
  73 #include <linux/proc_fs.h>
  74 #include <linux/init.h>
  75 #include <linux/skbuff.h>
  76 #include <linux/inetdevice.h>
  77 #include <linux/igmp.h>
  78 #include <linux/pkt_sched.h>
  79 #include <linux/mroute.h>
  80 #include <linux/netfilter_ipv4.h>
  81 #include <linux/random.h>
  82 #include <linux/rcupdate.h>
  83 #include <linux/slab.h>
  84 #include <linux/jhash.h>
  85 #include <net/dst.h>
  86 #include <net/dst_metadata.h>
  87 #include <net/inet_dscp.h>
  88 #include <net/net_namespace.h>
  89 #include <net/ip.h>
  90 #include <net/route.h>
  91 #include <net/inetpeer.h>
  92 #include <net/sock.h>
  93 #include <net/ip_fib.h>
  94 #include <net/nexthop.h>
  95 #include <net/tcp.h>
  96 #include <net/icmp.h>
  97 #include <net/xfrm.h>
  98 #include <net/lwtunnel.h>
  99 #include <net/netevent.h>
 100 #include <net/rtnetlink.h>
 101 #ifdef CONFIG_SYSCTL
 102 #include <linux/sysctl.h>
 103 #endif
 104 #include <net/secure_seq.h>
 105 #include <net/ip_tunnels.h>
 106
 107 #include "fib_lookup.h"
 108
 109 #define RT_GC_TIMEOUT (300*HZ)
 110
 111 #define DEFAULT_MIN_PMTU (512 + 20 + 20)
 112 #define DEFAULT_MTU_EXPIRES (10 * 60 * HZ)
 113 #define DEFAULT_MIN_ADVMSS 256
 114 static int ip_rt_max_size;
 115 static int ip_rt_redirect_number __read_mostly  = 9;
 116 static int ip_rt_redirect_load __read_mostly    = HZ / 50;
 117 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
 118 static int ip_rt_error_cost __read_mostly       = HZ;
 119 static int ip_rt_error_burst __read_mostly      = 5 * HZ;
 120
 121 static int ip_rt_gc_timeout __read_mostly       = RT_GC_TIMEOUT;
 122
 123 /*
 124  *      Interface to generic destination cache.
 125  */
 126
 127 INDIRECT_CALLABLE_SCOPE
 128 struct dst_entry        *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
 129 static unsigned int      ipv4_default_advmss(const struct dst_entry *dst);
 130 INDIRECT_CALLABLE_SCOPE
 131 unsigned int            ipv4_mtu(const struct dst_entry *dst);
 132 static void             ipv4_negative_advice(struct sock *sk,
 133                                              struct dst_entry *dst);
 134 static void              ipv4_link_failure(struct sk_buff *skb);
 135 static void              ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 136                                            struct sk_buff *skb, u32 mtu,
 137                                            bool confirm_neigh);
 138 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
 139                                         struct sk_buff *skb);
 140 static void             ipv4_dst_destroy(struct dst_entry *dst);
 141
 142 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
 143 {
 144         WARN_ON(1);
 145         return NULL;
 146 }
 147
 148 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 149                                            struct sk_buff *skb,
 150                                            const void *daddr);
 151 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
 152
 153 static struct dst_ops ipv4_dst_ops = {
 154         .family =               AF_INET,
 155         .check =                ipv4_dst_check,
 156         .default_advmss =       ipv4_default_advmss,
 157         .mtu =                  ipv4_mtu,
 158         .cow_metrics =          ipv4_cow_metrics,
 159         .destroy =              ipv4_dst_destroy,
 160         .negative_advice =      ipv4_negative_advice,
 161         .link_failure =         ipv4_link_failure,
 162         .update_pmtu =          ip_rt_update_pmtu,
 163         .redirect =             ip_do_redirect,
 164         .local_out =            __ip_local_out,
 165         .neigh_lookup =         ipv4_neigh_lookup,
 166         .confirm_neigh =        ipv4_confirm_neigh,
 167 };
 168
 169 #define ECN_OR_COST(class)      TC_PRIO_##class
 170
 171 const __u8 ip_tos2prio[16] = {
 172         TC_PRIO_BESTEFFORT,
 173         ECN_OR_COST(BESTEFFORT),
 174         TC_PRIO_BESTEFFORT,
 175         ECN_OR_COST(BESTEFFORT),
 176         TC_PRIO_BULK,
 177         ECN_OR_COST(BULK),
 178         TC_PRIO_BULK,
 179         ECN_OR_COST(BULK),
 180         TC_PRIO_INTERACTIVE,
 181         ECN_OR_COST(INTERACTIVE),
 182         TC_PRIO_INTERACTIVE,
 183         ECN_OR_COST(INTERACTIVE),
 184         TC_PRIO_INTERACTIVE_BULK,
 185         ECN_OR_COST(INTERACTIVE_BULK),
 186         TC_PRIO_INTERACTIVE_BULK,
 187         ECN_OR_COST(INTERACTIVE_BULK)
 188 };
 189 EXPORT_SYMBOL(ip_tos2prio);
 190
 191 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 192 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
 193
 194 #ifdef CONFIG_PROC_FS
 195 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 196 {
 197         if (*pos)
 198                 return NULL;
 199         return SEQ_START_TOKEN;
 200 }
 201
 202 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 203 {
 204         ++*pos;
 205         return NULL;
 206 }
 207
 208 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
 209 {
 210 }
 211
 212 static int rt_cache_seq_show(struct seq_file *seq, void *v)
 213 {
 214         if (v == SEQ_START_TOKEN)
 215                 seq_printf(seq, "%-127s\n",
 216                            "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
 217                            "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
 218                            "HHUptod\tSpecDst");
 219         return 0;
 220 }
 221
 222 static const struct seq_operations rt_cache_seq_ops = {
 223         .start  = rt_cache_seq_start,
 224         .next   = rt_cache_seq_next,
 225         .stop   = rt_cache_seq_stop,
 226         .show   = rt_cache_seq_show,
 227 };
 228
 229 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
 230 {
 231         int cpu;
 232
 233         if (*pos == 0)
 234                 return SEQ_START_TOKEN;
 235
 236         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
 237                 if (!cpu_possible(cpu))
 238                         continue;
 239                 *pos = cpu+1;
 240                 return &per_cpu(rt_cache_stat, cpu);
 241         }
 242         return NULL;
 243 }
 244
 245 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 246 {
 247         int cpu;
 248
 249         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
 250                 if (!cpu_possible(cpu))
 251                         continue;
 252                 *pos = cpu+1;
 253                 return &per_cpu(rt_cache_stat, cpu);
 254         }
 255         (*pos)++;
 256         return NULL;
 257
 258 }
 259
 260 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
 261 {
 262
 263 }
 264
 265 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 266 {
 267         struct rt_cache_stat *st = v;
 268
 269         if (v == SEQ_START_TOKEN) {
 270                 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");
 271                 return 0;
 272         }
 273
 274         seq_printf(seq, "%08x %08x %08x    %08x   %08x    %08x %08x       "
 275                         "%08x       %08x %08x     %08x    %08x %08x   "
 276                         "%08x     %08x        %08x        %08x\n",
 277                    dst_entries_get_slow(&ipv4_dst_ops),
 278                    0, /* st->in_hit */
 279                    st->in_slow_tot,
 280                    st->in_slow_mc,
 281                    st->in_no_route,
 282                    st->in_brd,
 283                    st->in_martian_dst,
 284                    st->in_martian_src,
 285
 286                    0, /* st->out_hit */
 287                    st->out_slow_tot,
 288                    st->out_slow_mc,
 289
 290                    0, /* st->gc_total */
 291                    0, /* st->gc_ignored */
 292                    0, /* st->gc_goal_miss */
 293                    0, /* st->gc_dst_overflow */
 294                    0, /* st->in_hlist_search */
 295                    0  /* st->out_hlist_search */
 296                 );
 297         return 0;
 298 }
 299
 300 static const struct seq_operations rt_cpu_seq_ops = {
 301         .start  = rt_cpu_seq_start,
 302         .next   = rt_cpu_seq_next,
 303         .stop   = rt_cpu_seq_stop,
 304         .show   = rt_cpu_seq_show,
 305 };
 306
 307 #ifdef CONFIG_IP_ROUTE_CLASSID
 308 static int rt_acct_proc_show(struct seq_file *m, void *v)
 309 {
 310         struct ip_rt_acct *dst, *src;
 311         unsigned int i, j;
 312
 313         dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
 314         if (!dst)
 315                 return -ENOMEM;
 316
 317         for_each_possible_cpu(i) {
 318                 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
 319                 for (j = 0; j < 256; j++) {
 320                         dst[j].o_bytes   += src[j].o_bytes;
 321                         dst[j].o_packets += src[j].o_packets;
 322                         dst[j].i_bytes   += src[j].i_bytes;
 323                         dst[j].i_packets += src[j].i_packets;
 324                 }
 325         }
 326
 327         seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
 328         kfree(dst);
 329         return 0;
 330 }
 331 #endif
 332
 333 static int __net_init ip_rt_do_proc_init(struct net *net)
 334 {
 335         struct proc_dir_entry *pde;
 336
 337         pde = proc_create_seq("rt_cache", 0444, net->proc_net,
 338                               &rt_cache_seq_ops);
 339         if (!pde)
 340                 goto err1;
 341
 342         pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
 343                               &rt_cpu_seq_ops);
 344         if (!pde)
 345                 goto err2;
 346
 347 #ifdef CONFIG_IP_ROUTE_CLASSID
 348         pde = proc_create_single("rt_acct", 0, net->proc_net,
 349                         rt_acct_proc_show);
 350         if (!pde)
 351                 goto err3;
 352 #endif
 353         return 0;
 354
 355 #ifdef CONFIG_IP_ROUTE_CLASSID
 356 err3:
 357         remove_proc_entry("rt_cache", net->proc_net_stat);
 358 #endif
 359 err2:
 360         remove_proc_entry("rt_cache", net->proc_net);
 361 err1:
 362         return -ENOMEM;
 363 }
 364
 365 static void __net_exit ip_rt_do_proc_exit(struct net *net)
 366 {
 367         remove_proc_entry("rt_cache", net->proc_net_stat);
 368         remove_proc_entry("rt_cache", net->proc_net);
 369 #ifdef CONFIG_IP_ROUTE_CLASSID
 370         remove_proc_entry("rt_acct", net->proc_net);
 371 #endif
 372 }
 373
 374 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 375         .init = ip_rt_do_proc_init,
 376         .exit = ip_rt_do_proc_exit,
 377 };
 378
 379 static int __init ip_rt_proc_init(void)
 380 {
 381         return register_pernet_subsys(&ip_rt_proc_ops);
 382 }
 383
 384 #else
 385 static inline int ip_rt_proc_init(void)
 386 {
 387         return 0;
 388 }
 389 #endif /* CONFIG_PROC_FS */
 390
 391 static inline bool rt_is_expired(const struct rtable *rth)
 392 {
 393         return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
 394 }
 395
 396 void rt_cache_flush(struct net *net)
 397 {
 398         rt_genid_bump_ipv4(net);
 399 }
 400
 401 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 402                                            struct sk_buff *skb,
 403                                            const void *daddr)
 404 {
 405         const struct rtable *rt = container_of(dst, struct rtable, dst);
 406         struct net_device *dev = dst->dev;
 407         struct neighbour *n;
 408
 409         rcu_read_lock();
 410
 411         if (likely(rt->rt_gw_family == AF_INET)) {
 412                 n = ip_neigh_gw4(dev, rt->rt_gw4);
 413         } else if (rt->rt_gw_family == AF_INET6) {
 414                 n = ip_neigh_gw6(dev, &rt->rt_gw6);
 415         } else {
 416                 __be32 pkey;
 417
 418                 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
 419                 n = ip_neigh_gw4(dev, pkey);
 420         }
 421
 422         if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
 423                 n = NULL;
 424
 425         rcu_read_unlock();
 426
 427         return n;
 428 }
 429
 430 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 431 {
 432         const struct rtable *rt = container_of(dst, struct rtable, dst);
 433         struct net_device *dev = dst->dev;
 434         const __be32 *pkey = daddr;
 435
 436         if (rt->rt_gw_family == AF_INET) {
 437                 pkey = (const __be32 *)&rt->rt_gw4;
 438         } else if (rt->rt_gw_family == AF_INET6) {
 439                 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
 440         } else if (!daddr ||
 441                  (rt->rt_flags &
 442                   (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
 443                 return;
 444         }
 445         __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
 446 }
 447
 448 /* Hash tables of size 2048..262144 depending on RAM size.
 449  * Each bucket uses 8 bytes.
 450  */
 451 static u32 ip_idents_mask __read_mostly;
 452 static atomic_t *ip_idents __read_mostly;
 453 static u32 *ip_tstamps __read_mostly;
 454
 455 /* In order to protect privacy, we add a perturbation to identifiers
 456  * if one generator is seldom used. This makes hard for an attacker
 457  * to infer how many packets were sent between two points in time.
 458  */
 459 static u32 ip_idents_reserve(u32 hash, int segs)
 460 {
 461         u32 bucket, old, now = (u32)jiffies;
 462         atomic_t *p_id;
 463         u32 *p_tstamp;
 464         u32 delta = 0;
 465
 466         bucket = hash & ip_idents_mask;
 467         p_tstamp = ip_tstamps + bucket;
 468         p_id = ip_idents + bucket;
 469         old = READ_ONCE(*p_tstamp);
 470
 471         if (old != now && cmpxchg(p_tstamp, old, now) == old)
 472                 delta = get_random_u32_below(now - old);
 473
 474         /* If UBSAN reports an error there, please make sure your compiler
 475          * supports -fno-strict-overflow before reporting it that was a bug
 476          * in UBSAN, and it has been fixed in GCC-8.
 477          */
 478         return atomic_add_return(segs + delta, p_id) - segs;
 479 }
 480
 481 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
 482 {
 483         u32 hash, id;
 484
 485         /* Note the following code is not safe, but this is okay. */
 486         if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
 487                 get_random_bytes(&net->ipv4.ip_id_key,
 488                                  sizeof(net->ipv4.ip_id_key));
 489
 490         hash = siphash_3u32((__force u32)iph->daddr,
 491                             (__force u32)iph->saddr,
 492                             iph->protocol,
 493                             &net->ipv4.ip_id_key);
 494         id = ip_idents_reserve(hash, segs);
 495         iph->id = htons(id);
 496 }
 497 EXPORT_SYMBOL(__ip_select_ident);
 498
 499 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
 500                              const struct sock *sk, const struct iphdr *iph,
 501                              int oif, __u8 tos, u8 prot, u32 mark,
 502                              int flow_flags)
 503 {
 504         __u8 scope = RT_SCOPE_UNIVERSE;
 505
 506         if (sk) {
 507                 oif = sk->sk_bound_dev_if;
 508                 mark = READ_ONCE(sk->sk_mark);
 509                 tos = ip_sock_rt_tos(sk);
 510                 scope = ip_sock_rt_scope(sk);
 511                 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
 512                                                     sk->sk_protocol;
 513         }
 514
 515         flowi4_init_output(fl4, oif, mark, tos & INET_DSCP_MASK, scope,
 516                            prot, flow_flags, iph->daddr, iph->saddr, 0, 0,
 517                            sock_net_uid(net, sk));
 518 }
 519
 520 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
 521                                const struct sock *sk)
 522 {
 523         const struct net *net = dev_net(skb->dev);
 524         const struct iphdr *iph = ip_hdr(skb);
 525         int oif = skb->dev->ifindex;
 526         u8 prot = iph->protocol;
 527         u32 mark = skb->mark;
 528         __u8 tos = iph->tos;
 529
 530         __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
 531 }
 532
 533 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
 534 {
 535         const struct inet_sock *inet = inet_sk(sk);
 536         const struct ip_options_rcu *inet_opt;
 537         __be32 daddr = inet->inet_daddr;
 538
 539         rcu_read_lock();
 540         inet_opt = rcu_dereference(inet->inet_opt);
 541         if (inet_opt && inet_opt->opt.srr)
 542                 daddr = inet_opt->opt.faddr;
 543         flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
 544                            ip_sock_rt_tos(sk),
 545                            ip_sock_rt_scope(sk),
 546                            inet_test_bit(HDRINCL, sk) ?
 547                                 IPPROTO_RAW : sk->sk_protocol,
 548                            inet_sk_flowi_flags(sk),
 549                            daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
 550         rcu_read_unlock();
 551 }
 552
 553 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
 554                                  const struct sk_buff *skb)
 555 {
 556         if (skb)
 557                 build_skb_flow_key(fl4, skb, sk);
 558         else
 559                 build_sk_flow_key(fl4, sk);
 560 }
 561
 562 static DEFINE_SPINLOCK(fnhe_lock);
 563
 564 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
 565 {
 566         struct rtable *rt;
 567
 568         rt = rcu_dereference(fnhe->fnhe_rth_input);
 569         if (rt) {
 570                 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
 571                 dst_dev_put(&rt->dst);
 572                 dst_release(&rt->dst);
 573         }
 574         rt = rcu_dereference(fnhe->fnhe_rth_output);
 575         if (rt) {
 576                 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
 577                 dst_dev_put(&rt->dst);
 578                 dst_release(&rt->dst);
 579         }
 580 }
 581
 582 static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
 583 {
 584         struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
 585         struct fib_nh_exception *fnhe, *oldest = NULL;
 586
 587         for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
 588                 fnhe = rcu_dereference_protected(*fnhe_p,
 589                                                  lockdep_is_held(&fnhe_lock));
 590                 if (!fnhe)
 591                         break;
 592                 if (!oldest ||
 593                     time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
 594                         oldest = fnhe;
 595                         oldest_p = fnhe_p;
 596                 }
 597         }
 598         fnhe_flush_routes(oldest);
 599         *oldest_p = oldest->fnhe_next;
 600         kfree_rcu(oldest, rcu);
 601 }
 602
 603 static u32 fnhe_hashfun(__be32 daddr)
 604 {
 605         static siphash_aligned_key_t fnhe_hash_key;
 606         u64 hval;
 607
 608         net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
 609         hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
 610         return hash_64(hval, FNHE_HASH_SHIFT);
 611 }
 612
 613 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
 614 {
 615         rt->rt_pmtu = fnhe->fnhe_pmtu;
 616         rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
 617         rt->dst.expires = fnhe->fnhe_expires;
 618
 619         if (fnhe->fnhe_gw) {
 620                 rt->rt_flags |= RTCF_REDIRECTED;
 621                 rt->rt_uses_gateway = 1;
 622                 rt->rt_gw_family = AF_INET;
 623                 rt->rt_gw4 = fnhe->fnhe_gw;
 624         }
 625 }
 626
 627 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
 628                                   __be32 gw, u32 pmtu, bool lock,
 629                                   unsigned long expires)
 630 {
 631         struct fnhe_hash_bucket *hash;
 632         struct fib_nh_exception *fnhe;
 633         struct rtable *rt;
 634         u32 genid, hval;
 635         unsigned int i;
 636         int depth;
 637
 638         genid = fnhe_genid(dev_net(nhc->nhc_dev));
 639         hval = fnhe_hashfun(daddr);
 640
 641         spin_lock_bh(&fnhe_lock);
 642
 643         hash = rcu_dereference(nhc->nhc_exceptions);
 644         if (!hash) {
 645                 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
 646                 if (!hash)
 647                         goto out_unlock;
 648                 rcu_assign_pointer(nhc->nhc_exceptions, hash);
 649         }
 650
 651         hash += hval;
 652
 653         depth = 0;
 654         for (fnhe = rcu_dereference(hash->chain); fnhe;
 655              fnhe = rcu_dereference(fnhe->fnhe_next)) {
 656                 if (fnhe->fnhe_daddr == daddr)
 657                         break;
 658                 depth++;
 659         }
 660
 661         if (fnhe) {
 662                 if (fnhe->fnhe_genid != genid)
 663                         fnhe->fnhe_genid = genid;
 664                 if (gw)
 665                         fnhe->fnhe_gw = gw;
 666                 if (pmtu) {
 667                         fnhe->fnhe_pmtu = pmtu;
 668                         fnhe->fnhe_mtu_locked = lock;
 669                 }
 670                 fnhe->fnhe_expires = max(1UL, expires);
 671                 /* Update all cached dsts too */
 672                 rt = rcu_dereference(fnhe->fnhe_rth_input);
 673                 if (rt)
 674                         fill_route_from_fnhe(rt, fnhe);
 675                 rt = rcu_dereference(fnhe->fnhe_rth_output);
 676                 if (rt)
 677                         fill_route_from_fnhe(rt, fnhe);
 678         } else {
 679                 /* Randomize max depth to avoid some side channels attacks. */
 680                 int max_depth = FNHE_RECLAIM_DEPTH +
 681                                 get_random_u32_below(FNHE_RECLAIM_DEPTH);
 682
 683                 while (depth > max_depth) {
 684                         fnhe_remove_oldest(hash);
 685                         depth--;
 686                 }
 687
 688                 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
 689                 if (!fnhe)
 690                         goto out_unlock;
 691
 692                 fnhe->fnhe_next = hash->chain;
 693
 694                 fnhe->fnhe_genid = genid;
 695                 fnhe->fnhe_daddr = daddr;
 696                 fnhe->fnhe_gw = gw;
 697                 fnhe->fnhe_pmtu = pmtu;
 698                 fnhe->fnhe_mtu_locked = lock;
 699                 fnhe->fnhe_expires = max(1UL, expires);
 700
 701                 rcu_assign_pointer(hash->chain, fnhe);
 702
 703                 /* Exception created; mark the cached routes for the nexthop
 704                  * stale, so anyone caching it rechecks if this exception
 705                  * applies to them.
 706                  */
 707                 rt = rcu_dereference(nhc->nhc_rth_input);
 708                 if (rt)
 709                         rt->dst.obsolete = DST_OBSOLETE_KILL;
 710
 711                 for_each_possible_cpu(i) {
 712                         struct rtable __rcu **prt;
 713
 714                         prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
 715                         rt = rcu_dereference(*prt);
 716                         if (rt)
 717                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 718                 }
 719         }
 720
 721         fnhe->fnhe_stamp = jiffies;
 722
 723 out_unlock:
 724         spin_unlock_bh(&fnhe_lock);
 725 }
 726
 727 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 728                              bool kill_route)
 729 {
 730         __be32 new_gw = icmp_hdr(skb)->un.gateway;
 731         __be32 old_gw = ip_hdr(skb)->saddr;
 732         struct net_device *dev = skb->dev;
 733         struct in_device *in_dev;
 734         struct fib_result res;
 735         struct neighbour *n;
 736         struct net *net;
 737
 738         switch (icmp_hdr(skb)->code & 7) {
 739         case ICMP_REDIR_NET:
 740         case ICMP_REDIR_NETTOS:
 741         case ICMP_REDIR_HOST:
 742         case ICMP_REDIR_HOSTTOS:
 743                 break;
 744
 745         default:
 746                 return;
 747         }
 748
 749         if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
 750                 return;
 751
 752         in_dev = __in_dev_get_rcu(dev);
 753         if (!in_dev)
 754                 return;
 755
 756         net = dev_net(dev);
 757         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
 758             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
 759             ipv4_is_zeronet(new_gw))
 760                 goto reject_redirect;
 761
 762         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
 763                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
 764                         goto reject_redirect;
 765                 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
 766                         goto reject_redirect;
 767         } else {
 768                 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
 769                         goto reject_redirect;
 770         }
 771
 772         n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw);
 773         if (!n)
 774                 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
 775         if (!IS_ERR(n)) {
 776                 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
 777                         neigh_event_send(n, NULL);
 778                 } else {
 779                         if (fib_lookup(net, fl4, &res, 0) == 0) {
 780                                 struct fib_nh_common *nhc;
 781
 782                                 fib_select_path(net, &res, fl4, skb);
 783                                 nhc = FIB_RES_NHC(res);
 784                                 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
 785                                                 0, false,
 786                                                 jiffies + ip_rt_gc_timeout);
 787                         }
 788                         if (kill_route)
 789                                 rt->dst.obsolete = DST_OBSOLETE_KILL;
 790                         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 791                 }
 792                 neigh_release(n);
 793         }
 794         return;
 795
 796 reject_redirect:
 797 #ifdef CONFIG_IP_ROUTE_VERBOSE
 798         if (IN_DEV_LOG_MARTIANS(in_dev)) {
 799                 const struct iphdr *iph = (const struct iphdr *) skb->data;
 800                 __be32 daddr = iph->daddr;
 801                 __be32 saddr = iph->saddr;
 802
 803                 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
 804                                      "  Advised path = %pI4 -> %pI4\n",
 805                                      &old_gw, dev->name, &new_gw,
 806                                      &saddr, &daddr);
 807         }
 808 #endif
 809         ;
 810 }
 811
 812 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
 813 {
 814         struct rtable *rt;
 815         struct flowi4 fl4;
 816         const struct iphdr *iph = (const struct iphdr *) skb->data;
 817         struct net *net = dev_net(skb->dev);
 818         int oif = skb->dev->ifindex;
 819         u8 prot = iph->protocol;
 820         u32 mark = skb->mark;
 821         __u8 tos = iph->tos;
 822
 823         rt = dst_rtable(dst);
 824
 825         __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
 826         __ip_do_redirect(rt, skb, &fl4, true);
 827 }
 828
 829 static void ipv4_negative_advice(struct sock *sk,
 830                                  struct dst_entry *dst)
 831 {
 832         struct rtable *rt = dst_rtable(dst);
 833
 834         if ((dst->obsolete > 0) ||
 835             (rt->rt_flags & RTCF_REDIRECTED) ||
 836             rt->dst.expires)
 837                 sk_dst_reset(sk);
 838 }
 839
 840 /*
 841  * Algorithm:
 842  *      1. The first ip_rt_redirect_number redirects are sent
 843  *         with exponential backoff, then we stop sending them at all,
 844  *         assuming that the host ignores our redirects.
 845  *      2. If we did not see packets requiring redirects
 846  *         during ip_rt_redirect_silence, we assume that the host
 847  *         forgot redirected route and start to send redirects again.
 848  *
 849  * This algorithm is much cheaper and more intelligent than dumb load limiting
 850  * in icmp.c.
 851  *
 852  * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 853  * and "frag. need" (breaks PMTU discovery) in icmp.c.
 854  */
 855
 856 void ip_rt_send_redirect(struct sk_buff *skb)
 857 {
 858         struct rtable *rt = skb_rtable(skb);
 859         struct in_device *in_dev;
 860         struct inet_peer *peer;
 861         struct net *net;
 862         int log_martians;
 863         int vif;
 864
 865         rcu_read_lock();
 866         in_dev = __in_dev_get_rcu(rt->dst.dev);
 867         if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
 868                 rcu_read_unlock();
 869                 return;
 870         }
 871         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
 872         vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
 873         rcu_read_unlock();
 874
 875         net = dev_net(rt->dst.dev);
 876         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
 877         if (!peer) {
 878                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
 879                           rt_nexthop(rt, ip_hdr(skb)->daddr));
 880                 return;
 881         }
 882
 883         /* No redirected packets during ip_rt_redirect_silence;
 884          * reset the algorithm.
 885          */
 886         if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
 887                 peer->rate_tokens = 0;
 888                 peer->n_redirects = 0;
 889         }
 890
 891         /* Too many ignored redirects; do not send anything
 892          * set dst.rate_last to the last seen redirected packet.
 893          */
 894         if (peer->n_redirects >= ip_rt_redirect_number) {
 895                 peer->rate_last = jiffies;
 896                 goto out_put_peer;
 897         }
 898
 899         /* Check for load limit; set rate_last to the latest sent
 900          * redirect.
 901          */
 902         if (peer->n_redirects == 0 ||
 903             time_after(jiffies,
 904                        (peer->rate_last +
 905                         (ip_rt_redirect_load << peer->n_redirects)))) {
 906                 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
 907
 908                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 909                 peer->rate_last = jiffies;
 910                 ++peer->n_redirects;
 911                 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
 912                     peer->n_redirects == ip_rt_redirect_number)
 913                         net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 914                                              &ip_hdr(skb)->saddr, inet_iif(skb),
 915                                              &ip_hdr(skb)->daddr, &gw);
 916         }
 917 out_put_peer:
 918         inet_putpeer(peer);
 919 }
 920
 921 static int ip_error(struct sk_buff *skb)
 922 {
 923         struct rtable *rt = skb_rtable(skb);
 924         struct net_device *dev = skb->dev;
 925         struct in_device *in_dev;
 926         struct inet_peer *peer;
 927         unsigned long now;
 928         struct net *net;
 929         SKB_DR(reason);
 930         bool send;
 931         int code;
 932
 933         if (netif_is_l3_master(skb->dev)) {
 934                 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
 935                 if (!dev)
 936                         goto out;
 937         }
 938
 939         in_dev = __in_dev_get_rcu(dev);
 940
 941         /* IP on this device is disabled. */
 942         if (!in_dev)
 943                 goto out;
 944
 945         net = dev_net(rt->dst.dev);
 946         if (!IN_DEV_FORWARD(in_dev)) {
 947                 switch (rt->dst.error) {
 948                 case EHOSTUNREACH:
 949                         SKB_DR_SET(reason, IP_INADDRERRORS);
 950                         __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
 951                         break;
 952
 953                 case ENETUNREACH:
 954                         SKB_DR_SET(reason, IP_INNOROUTES);
 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                 SKB_DR_SET(reason, IP_INNOROUTES);
 971                 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
 972                 break;
 973         case EACCES:
 974                 code = ICMP_PKT_FILTERED;
 975                 break;
 976         }
 977
 978         peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
 979                                l3mdev_master_ifindex(skb->dev), 1);
 980
 981         send = true;
 982         if (peer) {
 983                 now = jiffies;
 984                 peer->rate_tokens += now - peer->rate_last;
 985                 if (peer->rate_tokens > ip_rt_error_burst)
 986                         peer->rate_tokens = ip_rt_error_burst;
 987                 peer->rate_last = now;
 988                 if (peer->rate_tokens >= ip_rt_error_cost)
 989                         peer->rate_tokens -= ip_rt_error_cost;
 990                 else
 991                         send = false;
 992                 inet_putpeer(peer);
 993         }
 994         if (send)
 995                 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
 996
 997 out:    kfree_skb_reason(skb, reason);
 998         return 0;
 999 }
1000
1001 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1002 {
1003         struct dst_entry *dst = &rt->dst;
1004         struct net *net = dev_net(dst->dev);
1005         struct fib_result res;
1006         bool lock = false;
1007         u32 old_mtu;
1008
1009         if (ip_mtu_locked(dst))
1010                 return;
1011
1012         old_mtu = ipv4_mtu(dst);
1013         if (old_mtu < mtu)
1014                 return;
1015
1016         if (mtu < net->ipv4.ip_rt_min_pmtu) {
1017                 lock = true;
1018                 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1019         }
1020
1021         if (rt->rt_pmtu == mtu && !lock &&
1022             time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1023                 return;
1024
1025         rcu_read_lock();
1026         if (fib_lookup(net, fl4, &res, 0) == 0) {
1027                 struct fib_nh_common *nhc;
1028
1029                 fib_select_path(net, &res, fl4, NULL);
1030                 nhc = FIB_RES_NHC(res);
1031                 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1032                                       jiffies + net->ipv4.ip_rt_mtu_expires);
1033         }
1034         rcu_read_unlock();
1035 }
1036
1037 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1038                               struct sk_buff *skb, u32 mtu,
1039                               bool confirm_neigh)
1040 {
1041         struct rtable *rt = dst_rtable(dst);
1042         struct flowi4 fl4;
1043
1044         ip_rt_build_flow_key(&fl4, sk, skb);
1045
1046         /* Don't make lookup fail for bridged encapsulations */
1047         if (skb && netif_is_any_bridge_port(skb->dev))
1048                 fl4.flowi4_oif = 0;
1049
1050         __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 }
1052
1053 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1054                       int oif, u8 protocol)
1055 {
1056         const struct iphdr *iph = (const struct iphdr *)skb->data;
1057         struct flowi4 fl4;
1058         struct rtable *rt;
1059         u32 mark = IP4_REPLY_MARK(net, skb->mark);
1060
1061         __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark,
1062                          0);
1063         rt = __ip_route_output_key(net, &fl4);
1064         if (!IS_ERR(rt)) {
1065                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1066                 ip_rt_put(rt);
1067         }
1068 }
1069 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1070
1071 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1072 {
1073         const struct iphdr *iph = (const struct iphdr *)skb->data;
1074         struct flowi4 fl4;
1075         struct rtable *rt;
1076
1077         __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1078
1079         if (!fl4.flowi4_mark)
1080                 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1081
1082         rt = __ip_route_output_key(sock_net(sk), &fl4);
1083         if (!IS_ERR(rt)) {
1084                 __ip_rt_update_pmtu(rt, &fl4, mtu);
1085                 ip_rt_put(rt);
1086         }
1087 }
1088
1089 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1090 {
1091         const struct iphdr *iph = (const struct iphdr *)skb->data;
1092         struct flowi4 fl4;
1093         struct rtable *rt;
1094         struct dst_entry *odst = NULL;
1095         bool new = false;
1096         struct net *net = sock_net(sk);
1097
1098         bh_lock_sock(sk);
1099
1100         if (!ip_sk_accept_pmtu(sk))
1101                 goto out;
1102
1103         odst = sk_dst_get(sk);
1104
1105         if (sock_owned_by_user(sk) || !odst) {
1106                 __ipv4_sk_update_pmtu(skb, sk, mtu);
1107                 goto out;
1108         }
1109
1110         __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1111
1112         rt = dst_rtable(odst);
1113         if (odst->obsolete && !odst->ops->check(odst, 0)) {
1114                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1115                 if (IS_ERR(rt))
1116                         goto out;
1117
1118                 new = true;
1119         }
1120
1121         __ip_rt_update_pmtu(dst_rtable(xfrm_dst_path(&rt->dst)), &fl4, mtu);
1122
1123         if (!dst_check(&rt->dst, 0)) {
1124                 if (new)
1125                         dst_release(&rt->dst);
1126
1127                 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1128                 if (IS_ERR(rt))
1129                         goto out;
1130
1131                 new = true;
1132         }
1133
1134         if (new)
1135                 sk_dst_set(sk, &rt->dst);
1136
1137 out:
1138         bh_unlock_sock(sk);
1139         dst_release(odst);
1140 }
1141 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1142
1143 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1144                    int oif, u8 protocol)
1145 {
1146         const struct iphdr *iph = (const struct iphdr *)skb->data;
1147         struct flowi4 fl4;
1148         struct rtable *rt;
1149
1150         __build_flow_key(net, &fl4, NULL, iph, oif, 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 = dst_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 net_device *dev;
1197         struct ip_options opt;
1198         int res;
1199
1200         /* Recompile ip options since IPCB may not be valid anymore.
1201          * Also check we have a reasonable ipv4 header.
1202          */
1203         if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1204             ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1205                 return;
1206
1207         memset(&opt, 0, sizeof(opt));
1208         if (ip_hdr(skb)->ihl > 5) {
1209                 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1210                         return;
1211                 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1212
1213                 rcu_read_lock();
1214                 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1215                 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
1216                 rcu_read_unlock();
1217
1218                 if (res)
1219                         return;
1220         }
1221         __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1222 }
1223
1224 static void ipv4_link_failure(struct sk_buff *skb)
1225 {
1226         struct rtable *rt;
1227
1228         ipv4_send_dest_unreach(skb);
1229
1230         rt = skb_rtable(skb);
1231         if (rt)
1232                 dst_set_expires(&rt->dst, 0);
1233 }
1234
1235 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1236 {
1237         pr_debug("%s: %pI4 -> %pI4, %s\n",
1238                  __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1239                  skb->dev ? skb->dev->name : "?");
1240         kfree_skb(skb);
1241         WARN_ON(1);
1242         return 0;
1243 }
1244
1245 /*
1246  * We do not cache source address of outgoing interface,
1247  * because it is used only by IP RR, TS and SRR options,
1248  * so that it out of fast path.
1249  *
1250  * BTW remember: "addr" is allowed to be not aligned
1251  * in IP options!
1252  */
1253
1254 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1255 {
1256         __be32 src;
1257
1258         if (rt_is_output_route(rt))
1259                 src = ip_hdr(skb)->saddr;
1260         else {
1261                 struct fib_result res;
1262                 struct iphdr *iph = ip_hdr(skb);
1263                 struct flowi4 fl4 = {
1264                         .daddr = iph->daddr,
1265                         .saddr = iph->saddr,
1266                         .flowi4_tos = iph->tos & INET_DSCP_MASK,
1267                         .flowi4_oif = rt->dst.dev->ifindex,
1268                         .flowi4_iif = skb->dev->ifindex,
1269                         .flowi4_mark = skb->mark,
1270                 };
1271
1272                 rcu_read_lock();
1273                 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1274                         src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1275                 else
1276                         src = inet_select_addr(rt->dst.dev,
1277                                                rt_nexthop(rt, iph->daddr),
1278                                                RT_SCOPE_UNIVERSE);
1279                 rcu_read_unlock();
1280         }
1281         memcpy(addr, &src, 4);
1282 }
1283
1284 #ifdef CONFIG_IP_ROUTE_CLASSID
1285 static void set_class_tag(struct rtable *rt, u32 tag)
1286 {
1287         if (!(rt->dst.tclassid & 0xFFFF))
1288                 rt->dst.tclassid |= tag & 0xFFFF;
1289         if (!(rt->dst.tclassid & 0xFFFF0000))
1290                 rt->dst.tclassid |= tag & 0xFFFF0000;
1291 }
1292 #endif
1293
1294 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1295 {
1296         struct net *net = dev_net(dst->dev);
1297         unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1298         unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1299                                     net->ipv4.ip_rt_min_advmss);
1300
1301         return min(advmss, IPV4_MAX_PMTU - header_size);
1302 }
1303
1304 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1305 {
1306         return ip_dst_mtu_maybe_forward(dst, false);
1307 }
1308 EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1309
1310 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1311 {
1312         struct fnhe_hash_bucket *hash;
1313         struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1314         u32 hval = fnhe_hashfun(daddr);
1315
1316         spin_lock_bh(&fnhe_lock);
1317
1318         hash = rcu_dereference_protected(nhc->nhc_exceptions,
1319                                          lockdep_is_held(&fnhe_lock));
1320         hash += hval;
1321
1322         fnhe_p = &hash->chain;
1323         fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1324         while (fnhe) {
1325                 if (fnhe->fnhe_daddr == daddr) {
1326                         rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1327                                 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1328                         /* set fnhe_daddr to 0 to ensure it won't bind with
1329                          * new dsts in rt_bind_exception().
1330                          */
1331                         fnhe->fnhe_daddr = 0;
1332                         fnhe_flush_routes(fnhe);
1333                         kfree_rcu(fnhe, rcu);
1334                         break;
1335                 }
1336                 fnhe_p = &fnhe->fnhe_next;
1337                 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1338                                                  lockdep_is_held(&fnhe_lock));
1339         }
1340
1341         spin_unlock_bh(&fnhe_lock);
1342 }
1343
1344 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1345                                                __be32 daddr)
1346 {
1347         struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1348         struct fib_nh_exception *fnhe;
1349         u32 hval;
1350
1351         if (!hash)
1352                 return NULL;
1353
1354         hval = fnhe_hashfun(daddr);
1355
1356         for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1357              fnhe = rcu_dereference(fnhe->fnhe_next)) {
1358                 if (fnhe->fnhe_daddr == daddr) {
1359                         if (fnhe->fnhe_expires &&
1360                             time_after(jiffies, fnhe->fnhe_expires)) {
1361                                 ip_del_fnhe(nhc, daddr);
1362                                 break;
1363                         }
1364                         return fnhe;
1365                 }
1366         }
1367         return NULL;
1368 }
1369
1370 /* MTU selection:
1371  * 1. mtu on route is locked - use it
1372  * 2. mtu from nexthop exception
1373  * 3. mtu from egress device
1374  */
1375
1376 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1377 {
1378         struct fib_nh_common *nhc = res->nhc;
1379         struct net_device *dev = nhc->nhc_dev;
1380         struct fib_info *fi = res->fi;
1381         u32 mtu = 0;
1382
1383         if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1384             fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1385                 mtu = fi->fib_mtu;
1386
1387         if (likely(!mtu)) {
1388                 struct fib_nh_exception *fnhe;
1389
1390                 fnhe = find_exception(nhc, daddr);
1391                 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1392                         mtu = fnhe->fnhe_pmtu;
1393         }
1394
1395         if (likely(!mtu))
1396                 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1397
1398         return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1399 }
1400
1401 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1402                               __be32 daddr, const bool do_cache)
1403 {
1404         bool ret = false;
1405
1406         spin_lock_bh(&fnhe_lock);
1407
1408         if (daddr == fnhe->fnhe_daddr) {
1409                 struct rtable __rcu **porig;
1410                 struct rtable *orig;
1411                 int genid = fnhe_genid(dev_net(rt->dst.dev));
1412
1413                 if (rt_is_input_route(rt))
1414                         porig = &fnhe->fnhe_rth_input;
1415                 else
1416                         porig = &fnhe->fnhe_rth_output;
1417                 orig = rcu_dereference(*porig);
1418
1419                 if (fnhe->fnhe_genid != genid) {
1420                         fnhe->fnhe_genid = genid;
1421                         fnhe->fnhe_gw = 0;
1422                         fnhe->fnhe_pmtu = 0;
1423                         fnhe->fnhe_expires = 0;
1424                         fnhe->fnhe_mtu_locked = false;
1425                         fnhe_flush_routes(fnhe);
1426                         orig = NULL;
1427                 }
1428                 fill_route_from_fnhe(rt, fnhe);
1429                 if (!rt->rt_gw4) {
1430                         rt->rt_gw4 = daddr;
1431                         rt->rt_gw_family = AF_INET;
1432                 }
1433
1434                 if (do_cache) {
1435                         dst_hold(&rt->dst);
1436                         rcu_assign_pointer(*porig, rt);
1437                         if (orig) {
1438                                 dst_dev_put(&orig->dst);
1439                                 dst_release(&orig->dst);
1440                         }
1441                         ret = true;
1442                 }
1443
1444                 fnhe->fnhe_stamp = jiffies;
1445         }
1446         spin_unlock_bh(&fnhe_lock);
1447
1448         return ret;
1449 }
1450
1451 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1452 {
1453         struct rtable *orig, *prev, **p;
1454         bool ret = true;
1455
1456         if (rt_is_input_route(rt)) {
1457                 p = (struct rtable **)&nhc->nhc_rth_input;
1458         } else {
1459                 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1460         }
1461         orig = *p;
1462
1463         /* hold dst before doing cmpxchg() to avoid race condition
1464          * on this dst
1465          */
1466         dst_hold(&rt->dst);
1467         prev = cmpxchg(p, orig, rt);
1468         if (prev == orig) {
1469                 if (orig) {
1470                         rt_add_uncached_list(orig);
1471                         dst_release(&orig->dst);
1472                 }
1473         } else {
1474                 dst_release(&rt->dst);
1475                 ret = false;
1476         }
1477
1478         return ret;
1479 }
1480
1481 struct uncached_list {
1482         spinlock_t              lock;
1483         struct list_head        head;
1484 };
1485
1486 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1487
1488 void rt_add_uncached_list(struct rtable *rt)
1489 {
1490         struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1491
1492         rt->dst.rt_uncached_list = ul;
1493
1494         spin_lock_bh(&ul->lock);
1495         list_add_tail(&rt->dst.rt_uncached, &ul->head);
1496         spin_unlock_bh(&ul->lock);
1497 }
1498
1499 void rt_del_uncached_list(struct rtable *rt)
1500 {
1501         if (!list_empty(&rt->dst.rt_uncached)) {
1502                 struct uncached_list *ul = rt->dst.rt_uncached_list;
1503
1504                 spin_lock_bh(&ul->lock);
1505                 list_del_init(&rt->dst.rt_uncached);
1506                 spin_unlock_bh(&ul->lock);
1507         }
1508 }
1509
1510 static void ipv4_dst_destroy(struct dst_entry *dst)
1511 {
1512         ip_dst_metrics_put(dst);
1513         rt_del_uncached_list(dst_rtable(dst));
1514 }
1515
1516 void rt_flush_dev(struct net_device *dev)
1517 {
1518         struct rtable *rt, *safe;
1519         int cpu;
1520
1521         for_each_possible_cpu(cpu) {
1522                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1523
1524                 if (list_empty(&ul->head))
1525                         continue;
1526
1527                 spin_lock_bh(&ul->lock);
1528                 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1529                         if (rt->dst.dev != dev)
1530                                 continue;
1531                         rt->dst.dev = blackhole_netdev;
1532                         netdev_ref_replace(dev, blackhole_netdev,
1533                                            &rt->dst.dev_tracker, GFP_ATOMIC);
1534                         list_del_init(&rt->dst.rt_uncached);
1535                 }
1536                 spin_unlock_bh(&ul->lock);
1537         }
1538 }
1539
1540 static bool rt_cache_valid(const struct rtable *rt)
1541 {
1542         return  rt &&
1543                 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1544                 !rt_is_expired(rt);
1545 }
1546
1547 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1548                            const struct fib_result *res,
1549                            struct fib_nh_exception *fnhe,
1550                            struct fib_info *fi, u16 type, u32 itag,
1551                            const bool do_cache)
1552 {
1553         bool cached = false;
1554
1555         if (fi) {
1556                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1557
1558                 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1559                         rt->rt_uses_gateway = 1;
1560                         rt->rt_gw_family = nhc->nhc_gw_family;
1561                         /* only INET and INET6 are supported */
1562                         if (likely(nhc->nhc_gw_family == AF_INET))
1563                                 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1564                         else
1565                                 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1566                 }
1567
1568                 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1569
1570 #ifdef CONFIG_IP_ROUTE_CLASSID
1571                 if (nhc->nhc_family == AF_INET) {
1572                         struct fib_nh *nh;
1573
1574                         nh = container_of(nhc, struct fib_nh, nh_common);
1575                         rt->dst.tclassid = nh->nh_tclassid;
1576                 }
1577 #endif
1578                 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1579                 if (unlikely(fnhe))
1580                         cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1581                 else if (do_cache)
1582                         cached = rt_cache_route(nhc, rt);
1583                 if (unlikely(!cached)) {
1584                         /* Routes we intend to cache in nexthop exception or
1585                          * FIB nexthop have the DST_NOCACHE bit clear.
1586                          * However, if we are unsuccessful at storing this
1587                          * route into the cache we really need to set it.
1588                          */
1589                         if (!rt->rt_gw4) {
1590                                 rt->rt_gw_family = AF_INET;
1591                                 rt->rt_gw4 = daddr;
1592                         }
1593                         rt_add_uncached_list(rt);
1594                 }
1595         } else
1596                 rt_add_uncached_list(rt);
1597
1598 #ifdef CONFIG_IP_ROUTE_CLASSID
1599 #ifdef CONFIG_IP_MULTIPLE_TABLES
1600         set_class_tag(rt, res->tclassid);
1601 #endif
1602         set_class_tag(rt, itag);
1603 #endif
1604 }
1605
1606 struct rtable *rt_dst_alloc(struct net_device *dev,
1607                             unsigned int flags, u16 type,
1608                             bool noxfrm)
1609 {
1610         struct rtable *rt;
1611
1612         rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1613                        (noxfrm ? DST_NOXFRM : 0));
1614
1615         if (rt) {
1616                 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1617                 rt->rt_flags = flags;
1618                 rt->rt_type = type;
1619                 rt->rt_is_input = 0;
1620                 rt->rt_iif = 0;
1621                 rt->rt_pmtu = 0;
1622                 rt->rt_mtu_locked = 0;
1623                 rt->rt_uses_gateway = 0;
1624                 rt->rt_gw_family = 0;
1625                 rt->rt_gw4 = 0;
1626
1627                 rt->dst.output = ip_output;
1628                 if (flags & RTCF_LOCAL)
1629                         rt->dst.input = ip_local_deliver;
1630         }
1631
1632         return rt;
1633 }
1634 EXPORT_SYMBOL(rt_dst_alloc);
1635
1636 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1637 {
1638         struct rtable *new_rt;
1639
1640         new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1641                            rt->dst.flags);
1642
1643         if (new_rt) {
1644                 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1645                 new_rt->rt_flags = rt->rt_flags;
1646                 new_rt->rt_type = rt->rt_type;
1647                 new_rt->rt_is_input = rt->rt_is_input;
1648                 new_rt->rt_iif = rt->rt_iif;
1649                 new_rt->rt_pmtu = rt->rt_pmtu;
1650                 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1651                 new_rt->rt_gw_family = rt->rt_gw_family;
1652                 if (rt->rt_gw_family == AF_INET)
1653                         new_rt->rt_gw4 = rt->rt_gw4;
1654                 else if (rt->rt_gw_family == AF_INET6)
1655                         new_rt->rt_gw6 = rt->rt_gw6;
1656
1657                 new_rt->dst.input = rt->dst.input;
1658                 new_rt->dst.output = rt->dst.output;
1659                 new_rt->dst.error = rt->dst.error;
1660                 new_rt->dst.lastuse = jiffies;
1661                 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1662         }
1663         return new_rt;
1664 }
1665 EXPORT_SYMBOL(rt_dst_clone);
1666
1667 /* called in rcu_read_lock() section */
1668 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1669                           u8 tos, struct net_device *dev,
1670                           struct in_device *in_dev, u32 *itag)
1671 {
1672         int err;
1673
1674         /* Primary sanity checks. */
1675         if (!in_dev)
1676                 return -EINVAL;
1677
1678         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1679             skb->protocol != htons(ETH_P_IP))
1680                 return -EINVAL;
1681
1682         if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1683                 return -EINVAL;
1684
1685         if (ipv4_is_zeronet(saddr)) {
1686                 if (!ipv4_is_local_multicast(daddr) &&
1687                     ip_hdr(skb)->protocol != IPPROTO_IGMP)
1688                         return -EINVAL;
1689         } else {
1690                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1691                                           in_dev, itag);
1692                 if (err < 0)
1693                         return err;
1694         }
1695         return 0;
1696 }
1697
1698 /* called in rcu_read_lock() section */
1699 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1700                              u8 tos, struct net_device *dev, int our)
1701 {
1702         struct in_device *in_dev = __in_dev_get_rcu(dev);
1703         unsigned int flags = RTCF_MULTICAST;
1704         struct rtable *rth;
1705         u32 itag = 0;
1706         int err;
1707
1708         err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1709         if (err)
1710                 return err;
1711
1712         if (our)
1713                 flags |= RTCF_LOCAL;
1714
1715         if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1716                 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1717
1718         rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1719                            false);
1720         if (!rth)
1721                 return -ENOBUFS;
1722
1723 #ifdef CONFIG_IP_ROUTE_CLASSID
1724         rth->dst.tclassid = itag;
1725 #endif
1726         rth->dst.output = ip_rt_bug;
1727         rth->rt_is_input= 1;
1728
1729 #ifdef CONFIG_IP_MROUTE
1730         if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1731                 rth->dst.input = ip_mr_input;
1732 #endif
1733         RT_CACHE_STAT_INC(in_slow_mc);
1734
1735         skb_dst_drop(skb);
1736         skb_dst_set(skb, &rth->dst);
1737         return 0;
1738 }
1739
1740
1741 static void ip_handle_martian_source(struct net_device *dev,
1742                                      struct in_device *in_dev,
1743                                      struct sk_buff *skb,
1744                                      __be32 daddr,
1745                                      __be32 saddr)
1746 {
1747         RT_CACHE_STAT_INC(in_martian_src);
1748 #ifdef CONFIG_IP_ROUTE_VERBOSE
1749         if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1750                 /*
1751                  *      RFC1812 recommendation, if source is martian,
1752                  *      the only hint is MAC header.
1753                  */
1754                 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1755                         &daddr, &saddr, dev->name);
1756                 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1757                         print_hex_dump(KERN_WARNING, "ll header: ",
1758                                        DUMP_PREFIX_OFFSET, 16, 1,
1759                                        skb_mac_header(skb),
1760                                        dev->hard_header_len, false);
1761                 }
1762         }
1763 #endif
1764 }
1765
1766 /* called in rcu_read_lock() section */
1767 static int __mkroute_input(struct sk_buff *skb,
1768                            const struct fib_result *res,
1769                            struct in_device *in_dev,
1770                            __be32 daddr, __be32 saddr, u32 tos)
1771 {
1772         struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1773         struct net_device *dev = nhc->nhc_dev;
1774         struct fib_nh_exception *fnhe;
1775         struct rtable *rth;
1776         int err;
1777         struct in_device *out_dev;
1778         bool do_cache;
1779         u32 itag = 0;
1780
1781         /* get a working reference to the output device */
1782         out_dev = __in_dev_get_rcu(dev);
1783         if (!out_dev) {
1784                 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1785                 return -EINVAL;
1786         }
1787
1788         err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1789                                   in_dev->dev, in_dev, &itag);
1790         if (err < 0) {
1791                 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1792                                          saddr);
1793
1794                 goto cleanup;
1795         }
1796
1797         do_cache = res->fi && !itag;
1798         if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1799             skb->protocol == htons(ETH_P_IP)) {
1800                 __be32 gw;
1801
1802                 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1803                 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1804                     inet_addr_onlink(out_dev, saddr, gw))
1805                         IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1806         }
1807
1808         if (skb->protocol != htons(ETH_P_IP)) {
1809                 /* Not IP (i.e. ARP). Do not create route, if it is
1810                  * invalid for proxy arp. DNAT routes are always valid.
1811                  *
1812                  * Proxy arp feature have been extended to allow, ARP
1813                  * replies back to the same interface, to support
1814                  * Private VLAN switch technologies. See arp.c.
1815                  */
1816                 if (out_dev == in_dev &&
1817                     IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1818                         err = -EINVAL;
1819                         goto cleanup;
1820                 }
1821         }
1822
1823         if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1824                 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1825
1826         fnhe = find_exception(nhc, daddr);
1827         if (do_cache) {
1828                 if (fnhe)
1829                         rth = rcu_dereference(fnhe->fnhe_rth_input);
1830                 else
1831                         rth = rcu_dereference(nhc->nhc_rth_input);
1832                 if (rt_cache_valid(rth)) {
1833                         skb_dst_set_noref(skb, &rth->dst);
1834                         goto out;
1835                 }
1836         }
1837
1838         rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1839                            IN_DEV_ORCONF(out_dev, NOXFRM));
1840         if (!rth) {
1841                 err = -ENOBUFS;
1842                 goto cleanup;
1843         }
1844
1845         rth->rt_is_input = 1;
1846         RT_CACHE_STAT_INC(in_slow_tot);
1847
1848         rth->dst.input = ip_forward;
1849
1850         rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1851                        do_cache);
1852         lwtunnel_set_redirect(&rth->dst);
1853         skb_dst_set(skb, &rth->dst);
1854 out:
1855         err = 0;
1856  cleanup:
1857         return err;
1858 }
1859
1860 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1861 /* To make ICMP packets follow the right flow, the multipath hash is
1862  * calculated from the inner IP addresses.
1863  */
1864 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1865                                  struct flow_keys *hash_keys)
1866 {
1867         const struct iphdr *outer_iph = ip_hdr(skb);
1868         const struct iphdr *key_iph = outer_iph;
1869         const struct iphdr *inner_iph;
1870         const struct icmphdr *icmph;
1871         struct iphdr _inner_iph;
1872         struct icmphdr _icmph;
1873
1874         if (likely(outer_iph->protocol != IPPROTO_ICMP))
1875                 goto out;
1876
1877         if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1878                 goto out;
1879
1880         icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1881                                    &_icmph);
1882         if (!icmph)
1883                 goto out;
1884
1885         if (!icmp_is_err(icmph->type))
1886                 goto out;
1887
1888         inner_iph = skb_header_pointer(skb,
1889                                        outer_iph->ihl * 4 + sizeof(_icmph),
1890                                        sizeof(_inner_iph), &_inner_iph);
1891         if (!inner_iph)
1892                 goto out;
1893
1894         key_iph = inner_iph;
1895 out:
1896         hash_keys->addrs.v4addrs.src = key_iph->saddr;
1897         hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1898 }
1899
1900 static u32 fib_multipath_custom_hash_outer(const struct net *net,
1901                                            const struct sk_buff *skb,
1902                                            bool *p_has_inner)
1903 {
1904         u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1905         struct flow_keys keys, hash_keys;
1906
1907         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1908                 return 0;
1909
1910         memset(&hash_keys, 0, sizeof(hash_keys));
1911         skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1912
1913         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1914         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1915                 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1916         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1917                 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1918         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1919                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1920         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1921                 hash_keys.ports.src = keys.ports.src;
1922         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1923                 hash_keys.ports.dst = keys.ports.dst;
1924
1925         *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1926         return fib_multipath_hash_from_keys(net, &hash_keys);
1927 }
1928
1929 static u32 fib_multipath_custom_hash_inner(const struct net *net,
1930                                            const struct sk_buff *skb,
1931                                            bool has_inner)
1932 {
1933         u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1934         struct flow_keys keys, hash_keys;
1935
1936         /* We assume the packet carries an encapsulation, but if none was
1937          * encountered during dissection of the outer flow, then there is no
1938          * point in calling the flow dissector again.
1939          */
1940         if (!has_inner)
1941                 return 0;
1942
1943         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1944                 return 0;
1945
1946         memset(&hash_keys, 0, sizeof(hash_keys));
1947         skb_flow_dissect_flow_keys(skb, &keys, 0);
1948
1949         if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1950                 return 0;
1951
1952         if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1953                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1954                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1955                         hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1956                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1957                         hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1958         } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1959                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1960                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1961                         hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1962                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1963                         hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1964                 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1965                         hash_keys.tags.flow_label = keys.tags.flow_label;
1966         }
1967
1968         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1969                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1970         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1971                 hash_keys.ports.src = keys.ports.src;
1972         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1973                 hash_keys.ports.dst = keys.ports.dst;
1974
1975         return fib_multipath_hash_from_keys(net, &hash_keys);
1976 }
1977
1978 static u32 fib_multipath_custom_hash_skb(const struct net *net,
1979                                          const struct sk_buff *skb)
1980 {
1981         u32 mhash, mhash_inner;
1982         bool has_inner = true;
1983
1984         mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
1985         mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
1986
1987         return jhash_2words(mhash, mhash_inner, 0);
1988 }
1989
1990 static u32 fib_multipath_custom_hash_fl4(const struct net *net,
1991                                          const struct flowi4 *fl4)
1992 {
1993         u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1994         struct flow_keys hash_keys;
1995
1996         if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1997                 return 0;
1998
1999         memset(&hash_keys, 0, sizeof(hash_keys));
2000         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2001         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2002                 hash_keys.addrs.v4addrs.src = fl4->saddr;
2003         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2004                 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2005         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2006                 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2007         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2008                 hash_keys.ports.src = fl4->fl4_sport;
2009         if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2010                 hash_keys.ports.dst = fl4->fl4_dport;
2011
2012         return fib_multipath_hash_from_keys(net, &hash_keys);
2013 }
2014
2015 /* if skb is set it will be used and fl4 can be NULL */
2016 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2017                        const struct sk_buff *skb, struct flow_keys *flkeys)
2018 {
2019         u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2020         struct flow_keys hash_keys;
2021         u32 mhash = 0;
2022
2023         switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2024         case 0:
2025                 memset(&hash_keys, 0, sizeof(hash_keys));
2026                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2027                 if (skb) {
2028                         ip_multipath_l3_keys(skb, &hash_keys);
2029                 } else {
2030                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2031                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2032                 }
2033                 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2034                 break;
2035         case 1:
2036                 /* skb is currently provided only when forwarding */
2037                 if (skb) {
2038                         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2039                         struct flow_keys keys;
2040
2041                         /* short-circuit if we already have L4 hash present */
2042                         if (skb->l4_hash)
2043                                 return skb_get_hash_raw(skb) >> 1;
2044
2045                         memset(&hash_keys, 0, sizeof(hash_keys));
2046
2047                         if (!flkeys) {
2048                                 skb_flow_dissect_flow_keys(skb, &keys, flag);
2049                                 flkeys = &keys;
2050                         }
2051
2052                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2053                         hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2054                         hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2055                         hash_keys.ports.src = flkeys->ports.src;
2056                         hash_keys.ports.dst = flkeys->ports.dst;
2057                         hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2058                 } else {
2059                         memset(&hash_keys, 0, sizeof(hash_keys));
2060                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2061                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2062                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2063                         hash_keys.ports.src = fl4->fl4_sport;
2064                         hash_keys.ports.dst = fl4->fl4_dport;
2065                         hash_keys.basic.ip_proto = fl4->flowi4_proto;
2066                 }
2067                 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2068                 break;
2069         case 2:
2070                 memset(&hash_keys, 0, sizeof(hash_keys));
2071                 /* skb is currently provided only when forwarding */
2072                 if (skb) {
2073                         struct flow_keys keys;
2074
2075                         skb_flow_dissect_flow_keys(skb, &keys, 0);
2076                         /* Inner can be v4 or v6 */
2077                         if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2078                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2079                                 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2080                                 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2081                         } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2082                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2083                                 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2084                                 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2085                                 hash_keys.tags.flow_label = keys.tags.flow_label;
2086                                 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2087                         } else {
2088                                 /* Same as case 0 */
2089                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2090                                 ip_multipath_l3_keys(skb, &hash_keys);
2091                         }
2092                 } else {
2093                         /* Same as case 0 */
2094                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2095                         hash_keys.addrs.v4addrs.src = fl4->saddr;
2096                         hash_keys.addrs.v4addrs.dst = fl4->daddr;
2097                 }
2098                 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2099                 break;
2100         case 3:
2101                 if (skb)
2102                         mhash = fib_multipath_custom_hash_skb(net, skb);
2103                 else
2104                         mhash = fib_multipath_custom_hash_fl4(net, fl4);
2105                 break;
2106         }
2107
2108         if (multipath_hash)
2109                 mhash = jhash_2words(mhash, multipath_hash, 0);
2110
2111         return mhash >> 1;
2112 }
2113 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2114
2115 static int ip_mkroute_input(struct sk_buff *skb,
2116                             struct fib_result *res,
2117                             struct in_device *in_dev,
2118                             __be32 daddr, __be32 saddr, u32 tos,
2119                             struct flow_keys *hkeys)
2120 {
2121 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2122         if (res->fi && fib_info_num_path(res->fi) > 1) {
2123                 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2124
2125                 fib_select_multipath(res, h);
2126                 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2127         }
2128 #endif
2129
2130         /* create a routing cache entry */
2131         return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2132 }
2133
2134 /* Implements all the saddr-related checks as ip_route_input_slow(),
2135  * assuming daddr is valid and the destination is not a local broadcast one.
2136  * Uses the provided hint instead of performing a route lookup.
2137  */
2138 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2139                       u8 tos, struct net_device *dev,
2140                       const struct sk_buff *hint)
2141 {
2142         struct in_device *in_dev = __in_dev_get_rcu(dev);
2143         struct rtable *rt = skb_rtable(hint);
2144         struct net *net = dev_net(dev);
2145         int err = -EINVAL;
2146         u32 tag = 0;
2147
2148         if (!in_dev)
2149                 return -EINVAL;
2150
2151         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2152                 goto martian_source;
2153
2154         if (ipv4_is_zeronet(saddr))
2155                 goto martian_source;
2156
2157         if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2158                 goto martian_source;
2159
2160         if (rt->rt_type != RTN_LOCAL)
2161                 goto skip_validate_source;
2162
2163         tos &= INET_DSCP_MASK;
2164         err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2165         if (err < 0)
2166                 goto martian_source;
2167
2168 skip_validate_source:
2169         skb_dst_copy(skb, hint);
2170         return 0;
2171
2172 martian_source:
2173         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2174         return err;
2175 }
2176
2177 /* get device for dst_alloc with local routes */
2178 static struct net_device *ip_rt_get_dev(struct net *net,
2179                                         const struct fib_result *res)
2180 {
2181         struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2182         struct net_device *dev = NULL;
2183
2184         if (nhc)
2185                 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2186
2187         return dev ? : net->loopback_dev;
2188 }
2189
2190 /*
2191  *      NOTE. We drop all the packets that has local source
2192  *      addresses, because every properly looped back packet
2193  *      must have correct destination already attached by output routine.
2194  *      Changes in the enforced policies must be applied also to
2195  *      ip_route_use_hint().
2196  *
2197  *      Such approach solves two big problems:
2198  *      1. Not simplex devices are handled properly.
2199  *      2. IP spoofing attempts are filtered with 100% of guarantee.
2200  *      called with rcu_read_lock()
2201  */
2202
2203 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2204                                u8 tos, struct net_device *dev,
2205                                struct fib_result *res)
2206 {
2207         struct in_device *in_dev = __in_dev_get_rcu(dev);
2208         struct flow_keys *flkeys = NULL, _flkeys;
2209         struct net    *net = dev_net(dev);
2210         struct ip_tunnel_info *tun_info;
2211         int             err = -EINVAL;
2212         unsigned int    flags = 0;
2213         u32             itag = 0;
2214         struct rtable   *rth;
2215         struct flowi4   fl4;
2216         bool do_cache = true;
2217
2218         /* IP on this device is disabled. */
2219
2220         if (!in_dev)
2221                 goto out;
2222
2223         /* Check for the most weird martians, which can be not detected
2224          * by fib_lookup.
2225          */
2226
2227         tun_info = skb_tunnel_info(skb);
2228         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2229                 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2230         else
2231                 fl4.flowi4_tun_key.tun_id = 0;
2232         skb_dst_drop(skb);
2233
2234         if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2235                 goto martian_source;
2236
2237         res->fi = NULL;
2238         res->table = NULL;
2239         if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2240                 goto brd_input;
2241
2242         /* Accept zero addresses only to limited broadcast;
2243          * I even do not know to fix it or not. Waiting for complains :-)
2244          */
2245         if (ipv4_is_zeronet(saddr))
2246                 goto martian_source;
2247
2248         if (ipv4_is_zeronet(daddr))
2249                 goto martian_destination;
2250
2251         /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2252          * and call it once if daddr or/and saddr are loopback addresses
2253          */
2254         if (ipv4_is_loopback(daddr)) {
2255                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2256                         goto martian_destination;
2257         } else if (ipv4_is_loopback(saddr)) {
2258                 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2259                         goto martian_source;
2260         }
2261
2262         /*
2263          *      Now we are ready to route packet.
2264          */
2265         fl4.flowi4_l3mdev = 0;
2266         fl4.flowi4_oif = 0;
2267         fl4.flowi4_iif = dev->ifindex;
2268         fl4.flowi4_mark = skb->mark;
2269         fl4.flowi4_tos = tos;
2270         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2271         fl4.flowi4_flags = 0;
2272         fl4.daddr = daddr;
2273         fl4.saddr = saddr;
2274         fl4.flowi4_uid = sock_net_uid(net, NULL);
2275         fl4.flowi4_multipath_hash = 0;
2276
2277         if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2278                 flkeys = &_flkeys;
2279         } else {
2280                 fl4.flowi4_proto = 0;
2281                 fl4.fl4_sport = 0;
2282                 fl4.fl4_dport = 0;
2283         }
2284
2285         err = fib_lookup(net, &fl4, res, 0);
2286         if (err != 0) {
2287                 if (!IN_DEV_FORWARD(in_dev))
2288                         err = -EHOSTUNREACH;
2289                 goto no_route;
2290         }
2291
2292         if (res->type == RTN_BROADCAST) {
2293                 if (IN_DEV_BFORWARD(in_dev))
2294                         goto make_route;
2295                 /* not do cache if bc_forwarding is enabled */
2296                 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))
2297                         do_cache = false;
2298                 goto brd_input;
2299         }
2300
2301         if (res->type == RTN_LOCAL) {
2302                 err = fib_validate_source(skb, saddr, daddr, tos,
2303                                           0, dev, in_dev, &itag);
2304                 if (err < 0)
2305                         goto martian_source;
2306                 goto local_input;
2307         }
2308
2309         if (!IN_DEV_FORWARD(in_dev)) {
2310                 err = -EHOSTUNREACH;
2311                 goto no_route;
2312         }
2313         if (res->type != RTN_UNICAST)
2314                 goto martian_destination;
2315
2316 make_route:
2317         err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2318 out:    return err;
2319
2320 brd_input:
2321         if (skb->protocol != htons(ETH_P_IP))
2322                 goto e_inval;
2323
2324         if (!ipv4_is_zeronet(saddr)) {
2325                 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2326                                           in_dev, &itag);
2327                 if (err < 0)
2328                         goto martian_source;
2329         }
2330         flags |= RTCF_BROADCAST;
2331         res->type = RTN_BROADCAST;
2332         RT_CACHE_STAT_INC(in_brd);
2333
2334 local_input:
2335         if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2336                 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2337
2338         do_cache &= res->fi && !itag;
2339         if (do_cache) {
2340                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2341
2342                 rth = rcu_dereference(nhc->nhc_rth_input);
2343                 if (rt_cache_valid(rth)) {
2344                         skb_dst_set_noref(skb, &rth->dst);
2345                         err = 0;
2346                         goto out;
2347                 }
2348         }
2349
2350         rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2351                            flags | RTCF_LOCAL, res->type, false);
2352         if (!rth)
2353                 goto e_nobufs;
2354
2355         rth->dst.output= ip_rt_bug;
2356 #ifdef CONFIG_IP_ROUTE_CLASSID
2357         rth->dst.tclassid = itag;
2358 #endif
2359         rth->rt_is_input = 1;
2360
2361         RT_CACHE_STAT_INC(in_slow_tot);
2362         if (res->type == RTN_UNREACHABLE) {
2363                 rth->dst.input= ip_error;
2364                 rth->dst.error= -err;
2365                 rth->rt_flags   &= ~RTCF_LOCAL;
2366         }
2367
2368         if (do_cache) {
2369                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2370
2371                 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2372                 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2373                         WARN_ON(rth->dst.input == lwtunnel_input);
2374                         rth->dst.lwtstate->orig_input = rth->dst.input;
2375                         rth->dst.input = lwtunnel_input;
2376                 }
2377
2378                 if (unlikely(!rt_cache_route(nhc, rth)))
2379                         rt_add_uncached_list(rth);
2380         }
2381         skb_dst_set(skb, &rth->dst);
2382         err = 0;
2383         goto out;
2384
2385 no_route:
2386         RT_CACHE_STAT_INC(in_no_route);
2387         res->type = RTN_UNREACHABLE;
2388         res->fi = NULL;
2389         res->table = NULL;
2390         goto local_input;
2391
2392         /*
2393          *      Do not cache martian addresses: they should be logged (RFC1812)
2394          */
2395 martian_destination:
2396         RT_CACHE_STAT_INC(in_martian_dst);
2397 #ifdef CONFIG_IP_ROUTE_VERBOSE
2398         if (IN_DEV_LOG_MARTIANS(in_dev))
2399                 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2400                                      &daddr, &saddr, dev->name);
2401 #endif
2402
2403 e_inval:
2404         err = -EINVAL;
2405         goto out;
2406
2407 e_nobufs:
2408         err = -ENOBUFS;
2409         goto out;
2410
2411 martian_source:
2412         ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2413         goto out;
2414 }
2415
2416 /* called with rcu_read_lock held */
2417 static 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 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2468                          u8 tos, struct net_device *dev)
2469 {
2470         struct fib_result res;
2471         int err;
2472
2473         tos &= INET_DSCP_MASK;
2474         rcu_read_lock();
2475         err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2476         rcu_read_unlock();
2477
2478         return err;
2479 }
2480 EXPORT_SYMBOL(ip_route_input_noref);
2481
2482 /* called with rcu_read_lock() */
2483 static struct rtable *__mkroute_output(const struct fib_result *res,
2484                                        const struct flowi4 *fl4, int orig_oif,
2485                                        struct net_device *dev_out,
2486                                        unsigned int flags)
2487 {
2488         struct fib_info *fi = res->fi;
2489         struct fib_nh_exception *fnhe;
2490         struct in_device *in_dev;
2491         u16 type = res->type;
2492         struct rtable *rth;
2493         bool do_cache;
2494
2495         in_dev = __in_dev_get_rcu(dev_out);
2496         if (!in_dev)
2497                 return ERR_PTR(-EINVAL);
2498
2499         if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2500                 if (ipv4_is_loopback(fl4->saddr) &&
2501                     !(dev_out->flags & IFF_LOOPBACK) &&
2502                     !netif_is_l3_master(dev_out))
2503                         return ERR_PTR(-EINVAL);
2504
2505         if (ipv4_is_lbcast(fl4->daddr))
2506                 type = RTN_BROADCAST;
2507         else if (ipv4_is_multicast(fl4->daddr))
2508                 type = RTN_MULTICAST;
2509         else if (ipv4_is_zeronet(fl4->daddr))
2510                 return ERR_PTR(-EINVAL);
2511
2512         if (dev_out->flags & IFF_LOOPBACK)
2513                 flags |= RTCF_LOCAL;
2514
2515         do_cache = true;
2516         if (type == RTN_BROADCAST) {
2517                 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2518                 fi = NULL;
2519         } else if (type == RTN_MULTICAST) {
2520                 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2521                 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2522                                      fl4->flowi4_proto))
2523                         flags &= ~RTCF_LOCAL;
2524                 else
2525                         do_cache = false;
2526                 /* If multicast route do not exist use
2527                  * default one, but do not gateway in this case.
2528                  * Yes, it is hack.
2529                  */
2530                 if (fi && res->prefixlen < 4)
2531                         fi = NULL;
2532         } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2533                    (orig_oif != dev_out->ifindex)) {
2534                 /* For local routes that require a particular output interface
2535                  * we do not want to cache the result.  Caching the result
2536                  * causes incorrect behaviour when there are multiple source
2537                  * addresses on the interface, the end result being that if the
2538                  * intended recipient is waiting on that interface for the
2539                  * packet he won't receive it because it will be delivered on
2540                  * the loopback interface and the IP_PKTINFO ipi_ifindex will
2541                  * be set to the loopback interface as well.
2542                  */
2543                 do_cache = false;
2544         }
2545
2546         fnhe = NULL;
2547         do_cache &= fi != NULL;
2548         if (fi) {
2549                 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2550                 struct rtable __rcu **prth;
2551
2552                 fnhe = find_exception(nhc, fl4->daddr);
2553                 if (!do_cache)
2554                         goto add;
2555                 if (fnhe) {
2556                         prth = &fnhe->fnhe_rth_output;
2557                 } else {
2558                         if (unlikely(fl4->flowi4_flags &
2559                                      FLOWI_FLAG_KNOWN_NH &&
2560                                      !(nhc->nhc_gw_family &&
2561                                        nhc->nhc_scope == RT_SCOPE_LINK))) {
2562                                 do_cache = false;
2563                                 goto add;
2564                         }
2565                         prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2566                 }
2567                 rth = rcu_dereference(*prth);
2568                 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2569                         return rth;
2570         }
2571
2572 add:
2573         rth = rt_dst_alloc(dev_out, flags, type,
2574                            IN_DEV_ORCONF(in_dev, NOXFRM));
2575         if (!rth)
2576                 return ERR_PTR(-ENOBUFS);
2577
2578         rth->rt_iif = orig_oif;
2579
2580         RT_CACHE_STAT_INC(out_slow_tot);
2581
2582         if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2583                 if (flags & RTCF_LOCAL &&
2584                     !(dev_out->flags & IFF_LOOPBACK)) {
2585                         rth->dst.output = ip_mc_output;
2586                         RT_CACHE_STAT_INC(out_slow_mc);
2587                 }
2588 #ifdef CONFIG_IP_MROUTE
2589                 if (type == RTN_MULTICAST) {
2590                         if (IN_DEV_MFORWARD(in_dev) &&
2591                             !ipv4_is_local_multicast(fl4->daddr)) {
2592                                 rth->dst.input = ip_mr_input;
2593                                 rth->dst.output = ip_mc_output;
2594                         }
2595                 }
2596 #endif
2597         }
2598
2599         rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2600         lwtunnel_set_redirect(&rth->dst);
2601
2602         return rth;
2603 }
2604
2605 /*
2606  * Major route resolver routine.
2607  */
2608
2609 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2610                                         const struct sk_buff *skb)
2611 {
2612         struct fib_result res = {
2613                 .type           = RTN_UNSPEC,
2614                 .fi             = NULL,
2615                 .table          = NULL,
2616                 .tclassid       = 0,
2617         };
2618         struct rtable *rth;
2619
2620         fl4->flowi4_iif = LOOPBACK_IFINDEX;
2621         fl4->flowi4_tos &= INET_DSCP_MASK;
2622
2623         rcu_read_lock();
2624         rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2625         rcu_read_unlock();
2626
2627         return rth;
2628 }
2629 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2630
2631 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2632                                             struct fib_result *res,
2633                                             const struct sk_buff *skb)
2634 {
2635         struct net_device *dev_out = NULL;
2636         int orig_oif = fl4->flowi4_oif;
2637         unsigned int flags = 0;
2638         struct rtable *rth;
2639         int err;
2640
2641         if (fl4->saddr) {
2642                 if (ipv4_is_multicast(fl4->saddr) ||
2643                     ipv4_is_lbcast(fl4->saddr) ||
2644                     ipv4_is_zeronet(fl4->saddr)) {
2645                         rth = ERR_PTR(-EINVAL);
2646                         goto out;
2647                 }
2648
2649                 rth = ERR_PTR(-ENETUNREACH);
2650
2651                 /* I removed check for oif == dev_out->oif here.
2652                  * It was wrong for two reasons:
2653                  * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2654                  *    is assigned to multiple interfaces.
2655                  * 2. Moreover, we are allowed to send packets with saddr
2656                  *    of another iface. --ANK
2657                  */
2658
2659                 if (fl4->flowi4_oif == 0 &&
2660                     (ipv4_is_multicast(fl4->daddr) ||
2661                      ipv4_is_lbcast(fl4->daddr))) {
2662                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2663                         dev_out = __ip_dev_find(net, fl4->saddr, false);
2664                         if (!dev_out)
2665                                 goto out;
2666
2667                         /* Special hack: user can direct multicasts
2668                          * and limited broadcast via necessary interface
2669                          * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2670                          * This hack is not just for fun, it allows
2671                          * vic,vat and friends to work.
2672                          * They bind socket to loopback, set ttl to zero
2673                          * and expect that it will work.
2674                          * From the viewpoint of routing cache they are broken,
2675                          * because we are not allowed to build multicast path
2676                          * with loopback source addr (look, routing cache
2677                          * cannot know, that ttl is zero, so that packet
2678                          * will not leave this host and route is valid).
2679                          * Luckily, this hack is good workaround.
2680                          */
2681
2682                         fl4->flowi4_oif = dev_out->ifindex;
2683                         goto make_route;
2684                 }
2685
2686                 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2687                         /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2688                         if (!__ip_dev_find(net, fl4->saddr, false))
2689                                 goto out;
2690                 }
2691         }
2692
2693
2694         if (fl4->flowi4_oif) {
2695                 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2696                 rth = ERR_PTR(-ENODEV);
2697                 if (!dev_out)
2698                         goto out;
2699
2700                 /* RACE: Check return value of inet_select_addr instead. */
2701                 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2702                         rth = ERR_PTR(-ENETUNREACH);
2703                         goto out;
2704                 }
2705                 if (ipv4_is_local_multicast(fl4->daddr) ||
2706                     ipv4_is_lbcast(fl4->daddr) ||
2707                     fl4->flowi4_proto == IPPROTO_IGMP) {
2708                         if (!fl4->saddr)
2709                                 fl4->saddr = inet_select_addr(dev_out, 0,
2710                                                               RT_SCOPE_LINK);
2711                         goto make_route;
2712                 }
2713                 if (!fl4->saddr) {
2714                         if (ipv4_is_multicast(fl4->daddr))
2715                                 fl4->saddr = inet_select_addr(dev_out, 0,
2716                                                               fl4->flowi4_scope);
2717                         else if (!fl4->daddr)
2718                                 fl4->saddr = inet_select_addr(dev_out, 0,
2719                                                               RT_SCOPE_HOST);
2720                 }
2721         }
2722
2723         if (!fl4->daddr) {
2724                 fl4->daddr = fl4->saddr;
2725                 if (!fl4->daddr)
2726                         fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2727                 dev_out = net->loopback_dev;
2728                 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2729                 res->type = RTN_LOCAL;
2730                 flags |= RTCF_LOCAL;
2731                 goto make_route;
2732         }
2733
2734         err = fib_lookup(net, fl4, res, 0);
2735         if (err) {
2736                 res->fi = NULL;
2737                 res->table = NULL;
2738                 if (fl4->flowi4_oif &&
2739                     (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) {
2740                         /* Apparently, routing tables are wrong. Assume,
2741                          * that the destination is on link.
2742                          *
2743                          * WHY? DW.
2744                          * Because we are allowed to send to iface
2745                          * even if it has NO routes and NO assigned
2746                          * addresses. When oif is specified, routing
2747                          * tables are looked up with only one purpose:
2748                          * to catch if destination is gatewayed, rather than
2749                          * direct. Moreover, if MSG_DONTROUTE is set,
2750                          * we send packet, ignoring both routing tables
2751                          * and ifaddr state. --ANK
2752                          *
2753                          *
2754                          * We could make it even if oif is unknown,
2755                          * likely IPv6, but we do not.
2756                          */
2757
2758                         if (fl4->saddr == 0)
2759                                 fl4->saddr = inet_select_addr(dev_out, 0,
2760                                                               RT_SCOPE_LINK);
2761                         res->type = RTN_UNICAST;
2762                         goto make_route;
2763                 }
2764                 rth = ERR_PTR(err);
2765                 goto out;
2766         }
2767
2768         if (res->type == RTN_LOCAL) {
2769                 if (!fl4->saddr) {
2770                         if (res->fi->fib_prefsrc)
2771                                 fl4->saddr = res->fi->fib_prefsrc;
2772                         else
2773                                 fl4->saddr = fl4->daddr;
2774                 }
2775
2776                 /* L3 master device is the loopback for that domain */
2777                 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2778                         net->loopback_dev;
2779
2780                 /* make sure orig_oif points to fib result device even
2781                  * though packet rx/tx happens over loopback or l3mdev
2782                  */
2783                 orig_oif = FIB_RES_OIF(*res);
2784
2785                 fl4->flowi4_oif = dev_out->ifindex;
2786                 flags |= RTCF_LOCAL;
2787                 goto make_route;
2788         }
2789
2790         fib_select_path(net, res, fl4, skb);
2791
2792         dev_out = FIB_RES_DEV(*res);
2793
2794 make_route:
2795         rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2796
2797 out:
2798         return rth;
2799 }
2800
2801 static struct dst_ops ipv4_dst_blackhole_ops = {
2802         .family                 = AF_INET,
2803         .default_advmss         = ipv4_default_advmss,
2804         .neigh_lookup           = ipv4_neigh_lookup,
2805         .check                  = dst_blackhole_check,
2806         .cow_metrics            = dst_blackhole_cow_metrics,
2807         .update_pmtu            = dst_blackhole_update_pmtu,
2808         .redirect               = dst_blackhole_redirect,
2809         .mtu                    = dst_blackhole_mtu,
2810 };
2811
2812 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2813 {
2814         struct rtable *ort = dst_rtable(dst_orig);
2815         struct rtable *rt;
2816
2817         rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0);
2818         if (rt) {
2819                 struct dst_entry *new = &rt->dst;
2820
2821                 new->__use = 1;
2822                 new->input = dst_discard;
2823                 new->output = dst_discard_out;
2824
2825                 new->dev = net->loopback_dev;
2826                 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC);
2827
2828                 rt->rt_is_input = ort->rt_is_input;
2829                 rt->rt_iif = ort->rt_iif;
2830                 rt->rt_pmtu = ort->rt_pmtu;
2831                 rt->rt_mtu_locked = ort->rt_mtu_locked;
2832
2833                 rt->rt_genid = rt_genid_ipv4(net);
2834                 rt->rt_flags = ort->rt_flags;
2835                 rt->rt_type = ort->rt_type;
2836                 rt->rt_uses_gateway = ort->rt_uses_gateway;
2837                 rt->rt_gw_family = ort->rt_gw_family;
2838                 if (rt->rt_gw_family == AF_INET)
2839                         rt->rt_gw4 = ort->rt_gw4;
2840                 else if (rt->rt_gw_family == AF_INET6)
2841                         rt->rt_gw6 = ort->rt_gw6;
2842         }
2843
2844         dst_release(dst_orig);
2845
2846         return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2847 }
2848
2849 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2850                                     const struct sock *sk)
2851 {
2852         struct rtable *rt = __ip_route_output_key(net, flp4);
2853
2854         if (IS_ERR(rt))
2855                 return rt;
2856
2857         if (flp4->flowi4_proto) {
2858                 flp4->flowi4_oif = rt->dst.dev->ifindex;
2859                 rt = dst_rtable(xfrm_lookup_route(net, &rt->dst,
2860                                                   flowi4_to_flowi(flp4),
2861                                                   sk, 0));
2862         }
2863
2864         return rt;
2865 }
2866 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2867
2868 /* called with rcu_read_lock held */
2869 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2870                         struct rtable *rt, u32 table_id, dscp_t dscp,
2871                         struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2872                         u32 seq, unsigned int flags)
2873 {
2874         struct rtmsg *r;
2875         struct nlmsghdr *nlh;
2876         unsigned long expires = 0;
2877         u32 error;
2878         u32 metrics[RTAX_MAX];
2879
2880         nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2881         if (!nlh)
2882                 return -EMSGSIZE;
2883
2884         r = nlmsg_data(nlh);
2885         r->rtm_family    = AF_INET;
2886         r->rtm_dst_len  = 32;
2887         r->rtm_src_len  = 0;
2888         r->rtm_tos      = inet_dscp_to_dsfield(dscp);
2889         r->rtm_table    = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2890         if (nla_put_u32(skb, RTA_TABLE, table_id))
2891                 goto nla_put_failure;
2892         r->rtm_type     = rt->rt_type;
2893         r->rtm_scope    = RT_SCOPE_UNIVERSE;
2894         r->rtm_protocol = RTPROT_UNSPEC;
2895         r->rtm_flags    = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2896         if (rt->rt_flags & RTCF_NOTIFY)
2897                 r->rtm_flags |= RTM_F_NOTIFY;
2898         if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2899                 r->rtm_flags |= RTCF_DOREDIRECT;
2900
2901         if (nla_put_in_addr(skb, RTA_DST, dst))
2902                 goto nla_put_failure;
2903         if (src) {
2904                 r->rtm_src_len = 32;
2905                 if (nla_put_in_addr(skb, RTA_SRC, src))
2906                         goto nla_put_failure;
2907         }
2908         if (rt->dst.dev &&
2909             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2910                 goto nla_put_failure;
2911         if (rt->dst.lwtstate &&
2912             lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2913                 goto nla_put_failure;
2914 #ifdef CONFIG_IP_ROUTE_CLASSID
2915         if (rt->dst.tclassid &&
2916             nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2917                 goto nla_put_failure;
2918 #endif
2919         if (fl4 && !rt_is_input_route(rt) &&
2920             fl4->saddr != src) {
2921                 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2922                         goto nla_put_failure;
2923         }
2924         if (rt->rt_uses_gateway) {
2925                 if (rt->rt_gw_family == AF_INET &&
2926                     nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2927                         goto nla_put_failure;
2928                 } else if (rt->rt_gw_family == AF_INET6) {
2929                         int alen = sizeof(struct in6_addr);
2930                         struct nlattr *nla;
2931                         struct rtvia *via;
2932
2933                         nla = nla_reserve(skb, RTA_VIA, alen + 2);
2934                         if (!nla)
2935                                 goto nla_put_failure;
2936
2937                         via = nla_data(nla);
2938                         via->rtvia_family = AF_INET6;
2939                         memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2940                 }
2941         }
2942
2943         expires = rt->dst.expires;
2944         if (expires) {
2945                 unsigned long now = jiffies;
2946
2947                 if (time_before(now, expires))
2948                         expires -= now;
2949                 else
2950                         expires = 0;
2951         }
2952
2953         memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2954         if (rt->rt_pmtu && expires)
2955                 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2956         if (rt->rt_mtu_locked && expires)
2957                 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2958         if (rtnetlink_put_metrics(skb, metrics) < 0)
2959                 goto nla_put_failure;
2960
2961         if (fl4) {
2962                 if (fl4->flowi4_mark &&
2963                     nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2964                         goto nla_put_failure;
2965
2966                 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2967                     nla_put_u32(skb, RTA_UID,
2968                                 from_kuid_munged(current_user_ns(),
2969                                                  fl4->flowi4_uid)))
2970                         goto nla_put_failure;
2971
2972                 if (rt_is_input_route(rt)) {
2973 #ifdef CONFIG_IP_MROUTE
2974                         if (ipv4_is_multicast(dst) &&
2975                             !ipv4_is_local_multicast(dst) &&
2976                             IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {
2977                                 int err = ipmr_get_route(net, skb,
2978                                                          fl4->saddr, fl4->daddr,
2979                                                          r, portid);
2980
2981                                 if (err <= 0) {
2982                                         if (err == 0)
2983                                                 return 0;
2984                                         goto nla_put_failure;
2985                                 }
2986                         } else
2987 #endif
2988                                 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2989                                         goto nla_put_failure;
2990                 }
2991         }
2992
2993         error = rt->dst.error;
2994
2995         if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2996                 goto nla_put_failure;
2997
2998         nlmsg_end(skb, nlh);
2999         return 0;
3000
3001 nla_put_failure:
3002         nlmsg_cancel(skb, nlh);
3003         return -EMSGSIZE;
3004 }
3005
3006 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3007                             struct netlink_callback *cb, u32 table_id,
3008                             struct fnhe_hash_bucket *bucket, int genid,
3009                             int *fa_index, int fa_start, unsigned int flags)
3010 {
3011         int i;
3012
3013         for (i = 0; i < FNHE_HASH_SIZE; i++) {
3014                 struct fib_nh_exception *fnhe;
3015
3016                 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3017                      fnhe = rcu_dereference(fnhe->fnhe_next)) {
3018                         struct rtable *rt;
3019                         int err;
3020
3021                         if (*fa_index < fa_start)
3022                                 goto next;
3023
3024                         if (fnhe->fnhe_genid != genid)
3025                                 goto next;
3026
3027                         if (fnhe->fnhe_expires &&
3028                             time_after(jiffies, fnhe->fnhe_expires))
3029                                 goto next;
3030
3031                         rt = rcu_dereference(fnhe->fnhe_rth_input);
3032                         if (!rt)
3033                                 rt = rcu_dereference(fnhe->fnhe_rth_output);
3034                         if (!rt)
3035                                 goto next;
3036
3037                         err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3038                                            table_id, 0, NULL, skb,
3039                                            NETLINK_CB(cb->skb).portid,
3040                                            cb->nlh->nlmsg_seq, flags);
3041                         if (err)
3042                                 return err;
3043 next:
3044                         (*fa_index)++;
3045                 }
3046         }
3047
3048         return 0;
3049 }
3050
3051 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3052                        u32 table_id, struct fib_info *fi,
3053                        int *fa_index, int fa_start, unsigned int flags)
3054 {
3055         struct net *net = sock_net(cb->skb->sk);
3056         int nhsel, genid = fnhe_genid(net);
3057
3058         for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3059                 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3060                 struct fnhe_hash_bucket *bucket;
3061                 int err;
3062
3063                 if (nhc->nhc_flags & RTNH_F_DEAD)
3064                         continue;
3065
3066                 rcu_read_lock();
3067                 bucket = rcu_dereference(nhc->nhc_exceptions);
3068                 err = 0;
3069                 if (bucket)
3070                         err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3071                                                genid, fa_index, fa_start,
3072                                                flags);
3073                 rcu_read_unlock();
3074                 if (err)
3075                         return err;
3076         }
3077
3078         return 0;
3079 }
3080
3081 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3082                                                    u8 ip_proto, __be16 sport,
3083                                                    __be16 dport)
3084 {
3085         struct sk_buff *skb;
3086         struct iphdr *iph;
3087
3088         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3089         if (!skb)
3090                 return NULL;
3091
3092         /* Reserve room for dummy headers, this skb can pass
3093          * through good chunk of routing engine.
3094          */
3095         skb_reset_mac_header(skb);
3096         skb_reset_network_header(skb);
3097         skb->protocol = htons(ETH_P_IP);
3098         iph = skb_put(skb, sizeof(struct iphdr));
3099         iph->protocol = ip_proto;
3100         iph->saddr = src;
3101         iph->daddr = dst;
3102         iph->version = 0x4;
3103         iph->frag_off = 0;
3104         iph->ihl = 0x5;
3105         skb_set_transport_header(skb, skb->len);
3106
3107         switch (iph->protocol) {
3108         case IPPROTO_UDP: {
3109                 struct udphdr *udph;
3110
3111                 udph = skb_put_zero(skb, sizeof(struct udphdr));
3112                 udph->source = sport;
3113                 udph->dest = dport;
3114                 udph->len = htons(sizeof(struct udphdr));
3115                 udph->check = 0;
3116                 break;
3117         }
3118         case IPPROTO_TCP: {
3119                 struct tcphdr *tcph;
3120
3121                 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3122                 tcph->source    = sport;
3123                 tcph->dest      = dport;
3124                 tcph->doff      = sizeof(struct tcphdr) / 4;
3125                 tcph->rst = 1;
3126                 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3127                                             src, dst, 0);
3128                 break;
3129         }
3130         case IPPROTO_ICMP: {
3131                 struct icmphdr *icmph;
3132
3133                 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3134                 icmph->type = ICMP_ECHO;
3135                 icmph->code = 0;
3136         }
3137         }
3138
3139         return skb;
3140 }
3141
3142 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3143                                        const struct nlmsghdr *nlh,
3144                                        struct nlattr **tb,
3145                                        struct netlink_ext_ack *extack)
3146 {
3147         struct rtmsg *rtm;
3148         int i, err;
3149
3150         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3151                 NL_SET_ERR_MSG(extack,
3152                                "ipv4: Invalid header for route get request");
3153                 return -EINVAL;
3154         }
3155
3156         if (!netlink_strict_get_check(skb))
3157                 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3158                                               rtm_ipv4_policy, extack);
3159
3160         rtm = nlmsg_data(nlh);
3161         if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3162             (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3163             rtm->rtm_table || rtm->rtm_protocol ||
3164             rtm->rtm_scope || rtm->rtm_type) {
3165                 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3166                 return -EINVAL;
3167         }
3168
3169         if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3170                                RTM_F_LOOKUP_TABLE |
3171                                RTM_F_FIB_MATCH)) {
3172                 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3173                 return -EINVAL;
3174         }
3175
3176         err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3177                                             rtm_ipv4_policy, extack);
3178         if (err)
3179                 return err;
3180
3181         if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3182             (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3183                 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3184                 return -EINVAL;
3185         }
3186
3187         for (i = 0; i <= RTA_MAX; i++) {
3188                 if (!tb[i])
3189                         continue;
3190
3191                 switch (i) {
3192                 case RTA_IIF:
3193                 case RTA_OIF:
3194                 case RTA_SRC:
3195                 case RTA_DST:
3196                 case RTA_IP_PROTO:
3197                 case RTA_SPORT:
3198                 case RTA_DPORT:
3199                 case RTA_MARK:
3200                 case RTA_UID:
3201                         break;
3202                 default:
3203                         NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3204                         return -EINVAL;
3205                 }
3206         }
3207
3208         return 0;
3209 }
3210
3211 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3212                              struct netlink_ext_ack *extack)
3213 {
3214         struct net *net = sock_net(in_skb->sk);
3215         struct nlattr *tb[RTA_MAX+1];
3216         u32 table_id = RT_TABLE_MAIN;
3217         __be16 sport = 0, dport = 0;
3218         struct fib_result res = {};
3219         u8 ip_proto = IPPROTO_UDP;
3220         struct rtable *rt = NULL;
3221         struct sk_buff *skb;
3222         struct rtmsg *rtm;
3223         struct flowi4 fl4 = {};
3224         __be32 dst = 0;
3225         __be32 src = 0;
3226         kuid_t uid;
3227         u32 iif;
3228         int err;
3229         int mark;
3230
3231         err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3232         if (err < 0)
3233                 return err;
3234
3235         rtm = nlmsg_data(nlh);
3236         src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3237         dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3238         iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3239         mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3240         if (tb[RTA_UID])
3241                 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3242         else
3243                 uid = (iif ? INVALID_UID : current_uid());
3244
3245         if (tb[RTA_IP_PROTO]) {
3246                 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3247                                                   &ip_proto, AF_INET, extack);
3248                 if (err)
3249                         return err;
3250         }
3251
3252         if (tb[RTA_SPORT])
3253                 sport = nla_get_be16(tb[RTA_SPORT]);
3254
3255         if (tb[RTA_DPORT])
3256                 dport = nla_get_be16(tb[RTA_DPORT]);
3257
3258         skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3259         if (!skb)
3260                 return -ENOBUFS;
3261
3262         fl4.daddr = dst;
3263         fl4.saddr = src;
3264         fl4.flowi4_tos = rtm->rtm_tos & INET_DSCP_MASK;
3265         fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3266         fl4.flowi4_mark = mark;
3267         fl4.flowi4_uid = uid;
3268         if (sport)
3269                 fl4.fl4_sport = sport;
3270         if (dport)
3271                 fl4.fl4_dport = dport;
3272         fl4.flowi4_proto = ip_proto;
3273
3274         rcu_read_lock();
3275
3276         if (iif) {
3277                 struct net_device *dev;
3278
3279                 dev = dev_get_by_index_rcu(net, iif);
3280                 if (!dev) {
3281                         err = -ENODEV;
3282                         goto errout_rcu;
3283                 }
3284
3285                 fl4.flowi4_iif = iif; /* for rt_fill_info */
3286                 skb->dev        = dev;
3287                 skb->mark       = mark;
3288                 err = ip_route_input_rcu(skb, dst, src,
3289                                          rtm->rtm_tos & INET_DSCP_MASK, dev,
3290                                          &res);
3291
3292                 rt = skb_rtable(skb);
3293                 if (err == 0 && rt->dst.error)
3294                         err = -rt->dst.error;
3295         } else {
3296                 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3297                 skb->dev = net->loopback_dev;
3298                 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3299                 err = 0;
3300                 if (IS_ERR(rt))
3301                         err = PTR_ERR(rt);
3302                 else
3303                         skb_dst_set(skb, &rt->dst);
3304         }
3305
3306         if (err)
3307                 goto errout_rcu;
3308
3309         if (rtm->rtm_flags & RTM_F_NOTIFY)
3310                 rt->rt_flags |= RTCF_NOTIFY;
3311
3312         if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3313                 table_id = res.table ? res.table->tb_id : 0;
3314
3315         /* reset skb for netlink reply msg */
3316         skb_trim(skb, 0);
3317         skb_reset_network_header(skb);
3318         skb_reset_transport_header(skb);
3319         skb_reset_mac_header(skb);
3320
3321         if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3322                 struct fib_rt_info fri;
3323
3324                 if (!res.fi) {
3325                         err = fib_props[res.type].error;
3326                         if (!err)
3327                                 err = -EHOSTUNREACH;
3328                         goto errout_rcu;
3329                 }
3330                 fri.fi = res.fi;
3331                 fri.tb_id = table_id;
3332                 fri.dst = res.prefix;
3333                 fri.dst_len = res.prefixlen;
3334                 fri.dscp = res.dscp;
3335                 fri.type = rt->rt_type;
3336                 fri.offload = 0;
3337                 fri.trap = 0;
3338                 fri.offload_failed = 0;
3339                 if (res.fa_head) {
3340                         struct fib_alias *fa;
3341
3342                         hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3343                                 u8 slen = 32 - fri.dst_len;
3344
3345                                 if (fa->fa_slen == slen &&
3346                                     fa->tb_id == fri.tb_id &&
3347                                     fa->fa_dscp == fri.dscp &&
3348                                     fa->fa_info == res.fi &&
3349                                     fa->fa_type == fri.type) {
3350                                         fri.offload = READ_ONCE(fa->offload);
3351                                         fri.trap = READ_ONCE(fa->trap);
3352                                         fri.offload_failed =
3353                                                 READ_ONCE(fa->offload_failed);
3354                                         break;
3355                                 }
3356                         }
3357                 }
3358                 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3359                                     nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3360         } else {
3361                 err = rt_fill_info(net, dst, src, rt, table_id, res.dscp, &fl4,
3362                                    skb, NETLINK_CB(in_skb).portid,
3363                                    nlh->nlmsg_seq, 0);
3364         }
3365         if (err < 0)
3366                 goto errout_rcu;
3367
3368         rcu_read_unlock();
3369
3370         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3371
3372 errout_free:
3373         return err;
3374 errout_rcu:
3375         rcu_read_unlock();
3376         kfree_skb(skb);
3377         goto errout_free;
3378 }
3379
3380 void ip_rt_multicast_event(struct in_device *in_dev)
3381 {
3382         rt_cache_flush(dev_net(in_dev->dev));
3383 }
3384
3385 #ifdef CONFIG_SYSCTL
3386 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
3387 static int ip_rt_gc_min_interval __read_mostly  = HZ / 2;
3388 static int ip_rt_gc_elasticity __read_mostly    = 8;
3389 static int ip_min_valid_pmtu __read_mostly      = IPV4_MIN_MTU;
3390
3391 static int ipv4_sysctl_rtcache_flush(const struct ctl_table *__ctl, int write,
3392                 void *buffer, size_t *lenp, loff_t *ppos)
3393 {
3394         struct net *net = (struct net *)__ctl->extra1;
3395
3396         if (write) {
3397                 rt_cache_flush(net);
3398                 fnhe_genid_bump(net);
3399                 return 0;
3400         }
3401
3402         return -EINVAL;
3403 }
3404
3405 static struct ctl_table ipv4_route_table[] = {
3406         {
3407                 .procname       = "gc_thresh",
3408                 .data           = &ipv4_dst_ops.gc_thresh,
3409                 .maxlen         = sizeof(int),
3410                 .mode           = 0644,
3411                 .proc_handler   = proc_dointvec,
3412         },
3413         {
3414                 .procname       = "max_size",
3415                 .data           = &ip_rt_max_size,
3416                 .maxlen         = sizeof(int),
3417                 .mode           = 0644,
3418                 .proc_handler   = proc_dointvec,
3419         },
3420         {
3421                 /*  Deprecated. Use gc_min_interval_ms */
3422
3423                 .procname       = "gc_min_interval",
3424                 .data           = &ip_rt_gc_min_interval,
3425                 .maxlen         = sizeof(int),
3426                 .mode           = 0644,
3427                 .proc_handler   = proc_dointvec_jiffies,
3428         },
3429         {
3430                 .procname       = "gc_min_interval_ms",
3431                 .data           = &ip_rt_gc_min_interval,
3432                 .maxlen         = sizeof(int),
3433                 .mode           = 0644,
3434                 .proc_handler   = proc_dointvec_ms_jiffies,
3435         },
3436         {
3437                 .procname       = "gc_timeout",
3438                 .data           = &ip_rt_gc_timeout,
3439                 .maxlen         = sizeof(int),
3440                 .mode           = 0644,
3441                 .proc_handler   = proc_dointvec_jiffies,
3442         },
3443         {
3444                 .procname       = "gc_interval",
3445                 .data           = &ip_rt_gc_interval,
3446                 .maxlen         = sizeof(int),
3447                 .mode           = 0644,
3448                 .proc_handler   = proc_dointvec_jiffies,
3449         },
3450         {
3451                 .procname       = "redirect_load",
3452                 .data           = &ip_rt_redirect_load,
3453                 .maxlen         = sizeof(int),
3454                 .mode           = 0644,
3455                 .proc_handler   = proc_dointvec,
3456         },
3457         {
3458                 .procname       = "redirect_number",
3459                 .data           = &ip_rt_redirect_number,
3460                 .maxlen         = sizeof(int),
3461                 .mode           = 0644,
3462                 .proc_handler   = proc_dointvec,
3463         },
3464         {
3465                 .procname       = "redirect_silence",
3466                 .data           = &ip_rt_redirect_silence,
3467                 .maxlen         = sizeof(int),
3468                 .mode           = 0644,
3469                 .proc_handler   = proc_dointvec,
3470         },
3471         {
3472                 .procname       = "error_cost",
3473                 .data           = &ip_rt_error_cost,
3474                 .maxlen         = sizeof(int),
3475                 .mode           = 0644,
3476                 .proc_handler   = proc_dointvec,
3477         },
3478         {
3479                 .procname       = "error_burst",
3480                 .data           = &ip_rt_error_burst,
3481                 .maxlen         = sizeof(int),
3482                 .mode           = 0644,
3483                 .proc_handler   = proc_dointvec,
3484         },
3485         {
3486                 .procname       = "gc_elasticity",
3487                 .data           = &ip_rt_gc_elasticity,
3488                 .maxlen         = sizeof(int),
3489                 .mode           = 0644,
3490                 .proc_handler   = proc_dointvec,
3491         },
3492 };
3493
3494 static const char ipv4_route_flush_procname[] = "flush";
3495
3496 static struct ctl_table ipv4_route_netns_table[] = {
3497         {
3498                 .procname       = ipv4_route_flush_procname,
3499                 .maxlen         = sizeof(int),
3500                 .mode           = 0200,
3501                 .proc_handler   = ipv4_sysctl_rtcache_flush,
3502         },
3503         {
3504                 .procname       = "min_pmtu",
3505                 .data           = &init_net.ipv4.ip_rt_min_pmtu,
3506                 .maxlen         = sizeof(int),
3507                 .mode           = 0644,
3508                 .proc_handler   = proc_dointvec_minmax,
3509                 .extra1         = &ip_min_valid_pmtu,
3510         },
3511         {
3512                 .procname       = "mtu_expires",
3513                 .data           = &init_net.ipv4.ip_rt_mtu_expires,
3514                 .maxlen         = sizeof(int),
3515                 .mode           = 0644,
3516                 .proc_handler   = proc_dointvec_jiffies,
3517         },
3518         {
3519                 .procname   = "min_adv_mss",
3520                 .data       = &init_net.ipv4.ip_rt_min_advmss,
3521                 .maxlen     = sizeof(int),
3522                 .mode       = 0644,
3523                 .proc_handler   = proc_dointvec,
3524         },
3525 };
3526
3527 static __net_init int sysctl_route_net_init(struct net *net)
3528 {
3529         struct ctl_table *tbl;
3530         size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3531
3532         tbl = ipv4_route_netns_table;
3533         if (!net_eq(net, &init_net)) {
3534                 int i;
3535
3536                 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL);
3537                 if (!tbl)
3538                         goto err_dup;
3539
3540                 /* Don't export non-whitelisted sysctls to unprivileged users */
3541                 if (net->user_ns != &init_user_ns) {
3542                         if (tbl[0].procname != ipv4_route_flush_procname)
3543                                 table_size = 0;
3544                 }
3545
3546                 /* Update the variables to point into the current struct net
3547                  * except for the first element flush
3548                  */
3549                 for (i = 1; i < table_size; i++)
3550                         tbl[i].data += (void *)net - (void *)&init_net;
3551         }
3552         tbl[0].extra1 = net;
3553
3554         net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route",
3555                                                      tbl, table_size);
3556         if (!net->ipv4.route_hdr)
3557                 goto err_reg;
3558         return 0;
3559
3560 err_reg:
3561         if (tbl != ipv4_route_netns_table)
3562                 kfree(tbl);
3563 err_dup:
3564         return -ENOMEM;
3565 }
3566
3567 static __net_exit void sysctl_route_net_exit(struct net *net)
3568 {
3569         const struct ctl_table *tbl;
3570
3571         tbl = net->ipv4.route_hdr->ctl_table_arg;
3572         unregister_net_sysctl_table(net->ipv4.route_hdr);
3573         BUG_ON(tbl == ipv4_route_netns_table);
3574         kfree(tbl);
3575 }
3576
3577 static __net_initdata struct pernet_operations sysctl_route_ops = {
3578         .init = sysctl_route_net_init,
3579         .exit = sysctl_route_net_exit,
3580 };
3581 #endif
3582
3583 static __net_init int netns_ip_rt_init(struct net *net)
3584 {
3585         /* Set default value for namespaceified sysctls */
3586         net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3587         net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3588         net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3589         return 0;
3590 }
3591
3592 static struct pernet_operations __net_initdata ip_rt_ops = {
3593         .init = netns_ip_rt_init,
3594 };
3595
3596 static __net_init int rt_genid_init(struct net *net)
3597 {
3598         atomic_set(&net->ipv4.rt_genid, 0);
3599         atomic_set(&net->fnhe_genid, 0);
3600         atomic_set(&net->ipv4.dev_addr_genid, get_random_u32());
3601         return 0;
3602 }
3603
3604 static __net_initdata struct pernet_operations rt_genid_ops = {
3605         .init = rt_genid_init,
3606 };
3607
3608 static int __net_init ipv4_inetpeer_init(struct net *net)
3609 {
3610         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3611
3612         if (!bp)
3613                 return -ENOMEM;
3614         inet_peer_base_init(bp);
3615         net->ipv4.peers = bp;
3616         return 0;
3617 }
3618
3619 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3620 {
3621         struct inet_peer_base *bp = net->ipv4.peers;
3622
3623         net->ipv4.peers = NULL;
3624         inetpeer_invalidate_tree(bp);
3625         kfree(bp);
3626 }
3627
3628 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3629         .init   =       ipv4_inetpeer_init,
3630         .exit   =       ipv4_inetpeer_exit,
3631 };
3632
3633 #ifdef CONFIG_IP_ROUTE_CLASSID
3634 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3635 #endif /* CONFIG_IP_ROUTE_CLASSID */
3636
3637 int __init ip_rt_init(void)
3638 {
3639         void *idents_hash;
3640         int cpu;
3641
3642         /* For modern hosts, this will use 2 MB of memory */
3643         idents_hash = alloc_large_system_hash("IP idents",
3644                                               sizeof(*ip_idents) + sizeof(*ip_tstamps),
3645                                               0,
3646                                               16, /* one bucket per 64 KB */
3647                                               HASH_ZERO,
3648                                               NULL,
3649                                               &ip_idents_mask,
3650                                               2048,
3651                                               256*1024);
3652
3653         ip_idents = idents_hash;
3654
3655         get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3656
3657         ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3658
3659         for_each_possible_cpu(cpu) {
3660                 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3661
3662                 INIT_LIST_HEAD(&ul->head);
3663                 spin_lock_init(&ul->lock);
3664         }
3665 #ifdef CONFIG_IP_ROUTE_CLASSID
3666         ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3667         if (!ip_rt_acct)
3668                 panic("IP: failed to allocate ip_rt_acct\n");
3669 #endif
3670
3671         ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable,
3672                                               SLAB_HWCACHE_ALIGN | SLAB_PANIC);
3673
3674         ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3675
3676         if (dst_entries_init(&ipv4_dst_ops) < 0)
3677                 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3678
3679         if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3680                 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3681
3682         ipv4_dst_ops.gc_thresh = ~0;
3683         ip_rt_max_size = INT_MAX;
3684
3685         devinet_init();
3686         ip_fib_init();
3687
3688         if (ip_rt_proc_init())
3689                 pr_err("Unable to create route proc files\n");
3690 #ifdef CONFIG_XFRM
3691         xfrm_init();
3692         xfrm4_init();
3693 #endif
3694         rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3695                       RTNL_FLAG_DOIT_UNLOCKED);
3696
3697 #ifdef CONFIG_SYSCTL
3698         register_pernet_subsys(&sysctl_route_ops);
3699 #endif
3700         register_pernet_subsys(&ip_rt_ops);
3701         register_pernet_subsys(&rt_genid_ops);
3702         register_pernet_subsys(&ipv4_inetpeer_ops);
3703         return 0;
3704 }
3705
3706 #ifdef CONFIG_SYSCTL
3707 /*
3708  * We really need to sanitize the damn ipv4 init order, then all
3709  * this nonsense will go away.
3710  */
3711 void __init ip_static_sysctl_init(void)
3712 {
3713         register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3714 }
3715 #endif