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/netns/generic.h>
15 #include <net/route.h>
18 #include <linux/netfilter_bridge.h>
19 #include <linux/netfilter_ipv4.h>
20 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
21 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
22 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_zones.h>
26 static DEFINE_MUTEX(defrag4_mutex);
28 static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb,
34 err = ip_defrag(net, skb, user);
43 static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
46 u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
47 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
49 enum ip_conntrack_info ctinfo;
50 const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
52 zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
55 if (nf_bridge_in_prerouting(skb))
56 return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;
58 if (hooknum == NF_INET_PRE_ROUTING)
59 return IP_DEFRAG_CONNTRACK_IN + zone_id;
61 return IP_DEFRAG_CONNTRACK_OUT + zone_id;
64 static unsigned int ipv4_conntrack_defrag(void *priv,
66 const struct nf_hook_state *state)
68 struct sock *sk = skb->sk;
70 if (sk && sk_fullsock(sk) && (sk->sk_family == PF_INET) &&
71 inet_sk(sk)->nodefrag)
74 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
75 #if !IS_ENABLED(CONFIG_NF_NAT)
76 /* Previously seen (loopback)? Ignore. Do this before
78 if (skb_nfct(skb) && !nf_ct_is_template((struct nf_conn *)skb_nfct(skb)))
81 if (skb->_nfct == IP_CT_UNTRACKED)
84 /* Gather fragments. */
85 if (ip_is_fragment(ip_hdr(skb))) {
86 enum ip_defrag_users user =
87 nf_ct_defrag_user(state->hook, skb);
89 if (nf_ct_ipv4_gather_frags(state->net, skb, user))
95 static const struct nf_hook_ops ipv4_defrag_ops[] = {
97 .hook = ipv4_conntrack_defrag,
99 .hooknum = NF_INET_PRE_ROUTING,
100 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
103 .hook = ipv4_conntrack_defrag,
105 .hooknum = NF_INET_LOCAL_OUT,
106 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
110 static void __net_exit defrag4_net_exit(struct net *net)
112 if (net->nf.defrag_ipv4) {
113 nf_unregister_net_hooks(net, ipv4_defrag_ops,
114 ARRAY_SIZE(ipv4_defrag_ops));
115 net->nf.defrag_ipv4 = false;
119 static struct pernet_operations defrag4_net_ops = {
120 .exit = defrag4_net_exit,
123 static int __init nf_defrag_init(void)
125 return register_pernet_subsys(&defrag4_net_ops);
128 static void __exit nf_defrag_fini(void)
130 unregister_pernet_subsys(&defrag4_net_ops);
133 int nf_defrag_ipv4_enable(struct net *net)
139 if (net->nf.defrag_ipv4)
142 mutex_lock(&defrag4_mutex);
143 if (net->nf.defrag_ipv4)
146 err = nf_register_net_hooks(net, ipv4_defrag_ops,
147 ARRAY_SIZE(ipv4_defrag_ops));
149 net->nf.defrag_ipv4 = true;
152 mutex_unlock(&defrag4_mutex);
155 EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
157 module_init(nf_defrag_init);
158 module_exit(nf_defrag_fini);
160 MODULE_LICENSE("GPL");