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
  43 #ifdef CONFIG_BRIDGE_NETFILTER
  44         if (skb->nf_bridge &&
  45             skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
  46                 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
  47 #endif
  48         if (hooknum == NF_INET_PRE_ROUTING)
  49                 return IP6_DEFRAG_CONNTRACK_IN + zone;
  50         else
  51                 return IP6_DEFRAG_CONNTRACK_OUT + zone;
  52
  53 }
  54
  55 static unsigned int ipv6_defrag(unsigned int hooknum,
  56                                 struct sk_buff *skb,
  57                                 const struct net_device *in,
  58                                 const struct net_device *out,
  59                                 int (*okfn)(struct sk_buff *))
  60 {
  61         struct sk_buff *reasm;
  62
  63 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  64         /* Previously seen (loopback)?  */
  65         if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
  66                 return NF_ACCEPT;
  67 #endif
  68
  69         reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(hooknum, skb));
  70         /* queued */
  71         if (reasm == NULL)
  72                 return NF_STOLEN;
  73
  74         /* error occurred or not fragmented */
  75         if (reasm == skb)
  76                 return NF_ACCEPT;
  77
  78         nf_ct_frag6_consume_orig(reasm);
  79
  80         NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, reasm,
  81                        (struct net_device *) in, (struct net_device *) out,
  82                        okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
  83
  84         return NF_STOLEN;
  85 }
  86
  87 static struct nf_hook_ops ipv6_defrag_ops[] = {
  88         {
  89                 .hook           = ipv6_defrag,
  90                 .owner          = THIS_MODULE,
  91                 .pf             = NFPROTO_IPV6,
  92                 .hooknum        = NF_INET_PRE_ROUTING,
  93                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  94         },
  95         {
  96                 .hook           = ipv6_defrag,
  97                 .owner          = THIS_MODULE,
  98                 .pf             = NFPROTO_IPV6,
  99                 .hooknum        = NF_INET_LOCAL_OUT,
 100                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
 101         },
 102 };
 103
 104 static int __init nf_defrag_init(void)
 105 {
 106         int ret = 0;
 107
 108         ret = nf_ct_frag6_init();
 109         if (ret < 0) {
 110                 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
 111                 return ret;
 112         }
 113         ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 114         if (ret < 0) {
 115                 pr_err("nf_defrag_ipv6: can't register hooks\n");
 116                 goto cleanup_frag6;
 117         }
 118         return ret;
 119
 120 cleanup_frag6:
 121         nf_ct_frag6_cleanup();
 122         return ret;
 123
 124 }
 125
 126 static void __exit nf_defrag_fini(void)
 127 {
 128         nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 129         nf_ct_frag6_cleanup();
 130 }
 131
 132 void nf_defrag_ipv6_enable(void)
 133 {
 134 }
 135 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
 136
 137 module_init(nf_defrag_init);
 138 module_exit(nf_defrag_fini);
 139
 140 MODULE_LICENSE("GPL");