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_id = NF_CT_DEFAULT_ZONE_ID;
  37 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  38         if (skb->nfct) {
  39                 enum ip_conntrack_info ctinfo;
  40                 const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
  41
  42                 zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
  43         }
  44 #endif
  45         if (nf_bridge_in_prerouting(skb))
  46                 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;
  47
  48         if (hooknum == NF_INET_PRE_ROUTING)
  49                 return IP6_DEFRAG_CONNTRACK_IN + zone_id;
  50         else
  51                 return IP6_DEFRAG_CONNTRACK_OUT + zone_id;
  52 }
  53
  54 static unsigned int ipv6_defrag(const struct nf_hook_ops *ops,
  55                                 struct sk_buff *skb,
  56                                 const struct nf_hook_state *state)
  57 {
  58         struct sk_buff *reasm;
  59
  60 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  61         /* Previously seen (loopback)?  */
  62         if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
  63                 return NF_ACCEPT;
  64 #endif
  65
  66         reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(ops->hooknum, skb));
  67         /* queued */
  68         if (reasm == NULL)
  69                 return NF_STOLEN;
  70
  71         /* error occurred or not fragmented */
  72         if (reasm == skb)
  73                 return NF_ACCEPT;
  74
  75         nf_ct_frag6_consume_orig(reasm);
  76
  77         NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, state->sk, reasm,
  78                        state->in, state->out,
  79                        state->okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
  80
  81         return NF_STOLEN;
  82 }
  83
  84 static struct nf_hook_ops ipv6_defrag_ops[] = {
  85         {
  86                 .hook           = ipv6_defrag,
  87                 .owner          = THIS_MODULE,
  88                 .pf             = NFPROTO_IPV6,
  89                 .hooknum        = NF_INET_PRE_ROUTING,
  90                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  91         },
  92         {
  93                 .hook           = ipv6_defrag,
  94                 .owner          = THIS_MODULE,
  95                 .pf             = NFPROTO_IPV6,
  96                 .hooknum        = NF_INET_LOCAL_OUT,
  97                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
  98         },
  99 };
 100
 101 static int __init nf_defrag_init(void)
 102 {
 103         int ret = 0;
 104
 105         ret = nf_ct_frag6_init();
 106         if (ret < 0) {
 107                 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
 108                 return ret;
 109         }
 110         ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 111         if (ret < 0) {
 112                 pr_err("nf_defrag_ipv6: can't register hooks\n");
 113                 goto cleanup_frag6;
 114         }
 115         return ret;
 116
 117 cleanup_frag6:
 118         nf_ct_frag6_cleanup();
 119         return ret;
 120
 121 }
 122
 123 static void __exit nf_defrag_fini(void)
 124 {
 125         nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
 126         nf_ct_frag6_cleanup();
 127 }
 128
 129 void nf_defrag_ipv6_enable(void)
 130 {
 131 }
 132 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
 133
 134 module_init(nf_defrag_init);
 135 module_exit(nf_defrag_fini);
 136
 137 MODULE_LICENSE("GPL");