1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
9 #include <linux/types.h>
11 #include <linux/netfilter.h>
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
14 #include <net/route.h>
17 #include <linux/netfilter_bridge.h>
18 #include <linux/netfilter_ipv4.h>
19 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
20 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
21 #include <net/netfilter/nf_conntrack.h>
23 #include <net/netfilter/nf_conntrack_zones.h>
25 static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
32 err = ip_defrag(skb, user);
36 ip_send_check(ip_hdr(skb));
43 static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
46 u16 zone = NF_CT_DEFAULT_ZONE;
48 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
50 zone = nf_ct_zone((struct nf_conn *)skb->nfct);
53 #ifdef CONFIG_BRIDGE_NETFILTER
55 skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
56 return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
58 if (hooknum == NF_INET_PRE_ROUTING)
59 return IP_DEFRAG_CONNTRACK_IN + zone;
61 return IP_DEFRAG_CONNTRACK_OUT + zone;
64 static unsigned int ipv4_conntrack_defrag(const struct nf_hook_ops *ops,
66 const struct net_device *in,
67 const struct net_device *out,
68 int (*okfn)(struct sk_buff *))
70 struct sock *sk = skb->sk;
71 struct inet_sock *inet = inet_sk(skb->sk);
73 if (sk && (sk->sk_family == PF_INET) &&
77 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
78 #if !IS_ENABLED(CONFIG_NF_NAT)
79 /* Previously seen (loopback)? Ignore. Do this before
81 if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
85 /* Gather fragments. */
86 if (ip_is_fragment(ip_hdr(skb))) {
87 enum ip_defrag_users user =
88 nf_ct_defrag_user(ops->hooknum, skb);
90 if (nf_ct_ipv4_gather_frags(skb, user))
96 static struct nf_hook_ops ipv4_defrag_ops[] = {
98 .hook = ipv4_conntrack_defrag,
101 .hooknum = NF_INET_PRE_ROUTING,
102 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
105 .hook = ipv4_conntrack_defrag,
106 .owner = THIS_MODULE,
108 .hooknum = NF_INET_LOCAL_OUT,
109 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
113 static int __init nf_defrag_init(void)
115 return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
118 static void __exit nf_defrag_fini(void)
120 nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
123 void nf_defrag_ipv4_enable(void)
126 EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
128 module_init(nf_defrag_init);
129 module_exit(nf_defrag_fini);
131 MODULE_LICENSE("GPL");