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