net/ipv6/netfilter/nf_defrag_ipv6_hooks.c

   1 /* (C) 1999-2001 Paul `Rusty' Russell
   2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/ipv6.h>
  11 #include <linux/in6.h>
  12 #include <linux/netfilter.h>
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/icmp.h>
  16 #include <linux/sysctl.h>
  17 #include <net/ipv6.h>
  18 #include <net/inet_frag.h>
  19
  20 #include <linux/netfilter_ipv6.h>
  21 #include <linux/netfilter_bridge.h>
  22 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  23 #include <net/netfilter/nf_conntrack.h>
  24 #include <net/netfilter/nf_conntrack_helper.h>
  25 #include <net/netfilter/nf_conntrack_l4proto.h>
  26 #include <net/netfilter/nf_conntrack_l3proto.h>
  27 #include <net/netfilter/nf_conntrack_core.h>
  28 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  29 #endif
  30 #include <net/netfilter/nf_conntrack_zones.h>
  31 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  32
  33 static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
  34                                                 struct sk_buff *skb)
  35 {
  36         u16 zone = NF_CT_DEFAULT_ZONE;
  37
  38 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  39         if (skb->nfct)
  40                 zone = nf_ct_zone((struct nf_conn *)skb->nfct);
  41 #endif
  42         if (nf_bridge_in_prerouting(skb))
  43                 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
  44
  45         if (hooknum == NF_INET_PRE_ROUTING)
  46                 return IP6_DEFRAG_CONNTRACK_IN + zone;
  47         else
  48                 return IP6_DEFRAG_CONNTRACK_OUT + zone;
  49
  50 }
  51
  52 static unsigned int ipv6_defrag(const struct nf_hook_ops *ops,
  53                                 struct sk_buff *skb,
  54                                 const struct nf_hook_state *state)
  55 {
  56         struct sk_buff *reasm;
  57
  58 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  59         /* Previously seen (loopback)?  */
  60         if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
  61                 return NF_ACCEPT;
  62 #endif
  63
  64         reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(ops->hooknum, skb));
  65         /* queued */
  66         if (reasm == NULL)
  67                 return NF_STOLEN;
  68
  69         /* error occurred or not fragmented */
  70         if (reasm == skb)
  71                 return NF_ACCEPT;
  72
  73         nf_ct_frag6_consume_orig(reasm);
  74
  75         NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, state->sk, reasm,
  76                        state->in, state->out,
  77                        state->okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
  78
  79         return NF_STOLEN;
  80 }
  81
  82 static struct nf_hook_ops ipv6_defrag_ops[] = {
  83         {
  84                 .hook           = ipv6_defrag,
  85                 .owner          = THIS_MODULE,
  86                 .pf             = NFPROTO_IPV6,
  87                 .hooknum        = NF_INET_PRE_ROUTING,
  88                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  89         },
  90         {
  91                 .hook           = ipv6_defrag,
  92                 .owner          = THIS_MODULE,
  93                 .pf             = NFPROTO_IPV6,
  94                 .hooknum        = NF_INET_LOCAL_OUT,
  95                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  96         },
  97 };
  98
  99 static int __init nf_defrag_init(void)
 100 {
 101         int ret = 0;
 102
 103         ret = nf_ct_frag6_init();
 104         if (ret < 0) {
 105                 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
 106                 return ret;
 107         }
 108         ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 109         if (ret < 0) {
 110                 pr_err("nf_defrag_ipv6: can't register hooks\n");
 111                 goto cleanup_frag6;
 112         }
 113         return ret;
 114
 115 cleanup_frag6:
 116         nf_ct_frag6_cleanup();
 117         return ret;
 118
 119 }
 120
 121 static void __exit nf_defrag_fini(void)
 122 {
 123         nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 124         nf_ct_frag6_cleanup();
 125 }
 126
 127 void nf_defrag_ipv6_enable(void)
 128 {
 129 }
 130 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
 131
 132 module_init(nf_defrag_init);
 133 module_exit(nf_defrag_fini);
 134
 135 MODULE_LICENSE("GPL");