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 #include <net/netfilter/nf_conntrack.h>
  23 #include <net/netfilter/nf_conntrack_helper.h>
  24 #include <net/netfilter/nf_conntrack_l4proto.h>
  25 #include <net/netfilter/nf_conntrack_l3proto.h>
  26 #include <net/netfilter/nf_conntrack_core.h>
  27 #include <net/netfilter/nf_conntrack_zones.h>
  28 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  29 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  30
  31 static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
  32                                                 struct sk_buff *skb)
  33 {
  34         u16 zone = NF_CT_DEFAULT_ZONE;
  35
  36         if (skb->nfct)
  37                 zone = nf_ct_zone((struct nf_conn *)skb->nfct);
  38
  39 #ifdef CONFIG_BRIDGE_NETFILTER
  40         if (skb->nf_bridge &&
  41             skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
  42                 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
  43 #endif
  44         if (hooknum == NF_INET_PRE_ROUTING)
  45                 return IP6_DEFRAG_CONNTRACK_IN + zone;
  46         else
  47                 return IP6_DEFRAG_CONNTRACK_OUT + zone;
  48
  49 }
  50
  51 static unsigned int ipv6_defrag(unsigned int hooknum,
  52                                 struct sk_buff *skb,
  53                                 const struct net_device *in,
  54                                 const struct net_device *out,
  55                                 int (*okfn)(struct sk_buff *))
  56 {
  57         struct sk_buff *reasm;
  58
  59         /* Previously seen (loopback)?  */
  60         if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
  61                 return NF_ACCEPT;
  62
  63         reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(hooknum, skb));
  64         /* queued */
  65         if (reasm == NULL)
  66                 return NF_STOLEN;
  67
  68         /* error occured or not fragmented */
  69         if (reasm == skb)
  70                 return NF_ACCEPT;
  71
  72         nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in,
  73                            (struct net_device *)out, okfn);
  74
  75         return NF_STOLEN;
  76 }
  77
  78 static struct nf_hook_ops ipv6_defrag_ops[] = {
  79         {
  80                 .hook           = ipv6_defrag,
  81                 .owner          = THIS_MODULE,
  82                 .pf             = NFPROTO_IPV6,
  83                 .hooknum        = NF_INET_PRE_ROUTING,
  84                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  85         },
  86         {
  87                 .hook           = ipv6_defrag,
  88                 .owner          = THIS_MODULE,
  89                 .pf             = NFPROTO_IPV6,
  90                 .hooknum        = NF_INET_LOCAL_OUT,
  91                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  92         },
  93 };
  94
  95 static int __init nf_defrag_init(void)
  96 {
  97         int ret = 0;
  98
  99         ret = nf_ct_frag6_init();
 100         if (ret < 0) {
 101                 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
 102                 return ret;
 103         }
 104         ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 105         if (ret < 0) {
 106                 pr_err("nf_defrag_ipv6: can't register hooks\n");
 107                 goto cleanup_frag6;
 108         }
 109         return ret;
 110
 111 cleanup_frag6:
 112         nf_ct_frag6_cleanup();
 113         return ret;
 114
 115 }
 116
 117 static void __exit nf_defrag_fini(void)
 118 {
 119         nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 120         nf_ct_frag6_cleanup();
 121 }
 122
 123 void nf_defrag_ipv6_enable(void)
 124 {
 125 }
 126 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
 127
 128 module_init(nf_defrag_init);
 129 module_exit(nf_defrag_fini);
 130
 131 MODULE_LICENSE("GPL");