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9#include <linux/types.h>
10#include <linux/ip.h>
11#include <linux/netfilter.h>
12#include <linux/module.h>
13#include <linux/skbuff.h>
14#include <net/route.h>
15#include <net/ip.h>
16
17#include <linux/netfilter_bridge.h>
18#include <linux/netfilter_ipv4.h>
19#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
20#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
21#include <net/netfilter/nf_conntrack.h>
22#endif
23#include <net/netfilter/nf_conntrack_zones.h>
24
25
26static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
27{
28 int err;
29
30 skb_orphan(skb);
31
32 local_bh_disable();
33 err = ip_defrag(skb, user);
34 local_bh_enable();
35
36 if (!err)
37 ip_send_check(ip_hdr(skb));
38
39 return err;
40}
41
42static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
43 struct sk_buff *skb)
44{
45 u16 zone = NF_CT_DEFAULT_ZONE;
46
47#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
48 if (skb->nfct)
49 zone = nf_ct_zone((struct nf_conn *)skb->nfct);
50#endif
51
52#ifdef CONFIG_BRIDGE_NETFILTER
53 if (skb->nf_bridge &&
54 skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
55 return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
56#endif
57 if (hooknum == NF_INET_PRE_ROUTING)
58 return IP_DEFRAG_CONNTRACK_IN + zone;
59 else
60 return IP_DEFRAG_CONNTRACK_OUT + zone;
61}
62
63static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
64 struct sk_buff *skb,
65 const struct net_device *in,
66 const struct net_device *out,
67 int (*okfn)(struct sk_buff *))
68{
69 struct sock *sk = skb->sk;
70 struct inet_sock *inet = inet_sk(skb->sk);
71
72 if (sk && (sk->sk_family == PF_INET) &&
73 inet->nodefrag)
74 return NF_ACCEPT;
75
76#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
77#if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE)
78
79
80 if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
81 return NF_ACCEPT;
82#endif
83#endif
84
85 if (ip_is_fragment(ip_hdr(skb))) {
86 enum ip_defrag_users user = nf_ct_defrag_user(hooknum, skb);
87 if (nf_ct_ipv4_gather_frags(skb, user))
88 return NF_STOLEN;
89 }
90 return NF_ACCEPT;
91}
92
93static struct nf_hook_ops ipv4_defrag_ops[] = {
94 {
95 .hook = ipv4_conntrack_defrag,
96 .owner = THIS_MODULE,
97 .pf = PF_INET,
98 .hooknum = NF_INET_PRE_ROUTING,
99 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
100 },
101 {
102 .hook = ipv4_conntrack_defrag,
103 .owner = THIS_MODULE,
104 .pf = PF_INET,
105 .hooknum = NF_INET_LOCAL_OUT,
106 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
107 },
108};
109
110static int __init nf_defrag_init(void)
111{
112 return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
113}
114
115static void __exit nf_defrag_fini(void)
116{
117 nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
118}
119
120void nf_defrag_ipv4_enable(void)
121{
122}
123EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
124
125module_init(nf_defrag_init);
126module_exit(nf_defrag_fini);
127
128MODULE_LICENSE("GPL");
129