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5
6#include <linux/types.h>
7#include <linux/ipv6.h>
8#include <linux/in6.h>
9#include <linux/netfilter.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/icmp.h>
13#include <linux/sysctl.h>
14#include <net/ipv6_frag.h>
15
16#include <linux/netfilter_ipv6.h>
17#include <linux/netfilter_bridge.h>
18#if IS_ENABLED(CONFIG_NF_CONNTRACK)
19#include <net/netfilter/nf_conntrack.h>
20#include <net/netfilter/nf_conntrack_helper.h>
21#include <net/netfilter/nf_conntrack_l4proto.h>
22#include <net/netfilter/nf_conntrack_core.h>
23#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
24#endif
25#include <net/netfilter/nf_conntrack_zones.h>
26#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
27
28extern unsigned int nf_frag_pernet_id;
29
30static DEFINE_MUTEX(defrag6_mutex);
31
32static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
33 struct sk_buff *skb)
34{
35 u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
36#if IS_ENABLED(CONFIG_NF_CONNTRACK)
37 if (skb_nfct(skb)) {
38 enum ip_conntrack_info ctinfo;
39 const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
40
41 zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
42 }
43#endif
44 if (nf_bridge_in_prerouting(skb))
45 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;
46
47 if (hooknum == NF_INET_PRE_ROUTING)
48 return IP6_DEFRAG_CONNTRACK_IN + zone_id;
49 else
50 return IP6_DEFRAG_CONNTRACK_OUT + zone_id;
51}
52
53static unsigned int ipv6_defrag(void *priv,
54 struct sk_buff *skb,
55 const struct nf_hook_state *state)
56{
57 int err;
58
59#if IS_ENABLED(CONFIG_NF_CONNTRACK)
60
61 if (skb_nfct(skb) && !nf_ct_is_template((struct nf_conn *)skb_nfct(skb)))
62 return NF_ACCEPT;
63
64 if (skb->_nfct == IP_CT_UNTRACKED)
65 return NF_ACCEPT;
66#endif
67
68 err = nf_ct_frag6_gather(state->net, skb,
69 nf_ct6_defrag_user(state->hook, skb));
70
71 if (err == -EINPROGRESS)
72 return NF_STOLEN;
73
74 return err == 0 ? NF_ACCEPT : NF_DROP;
75}
76
77static const struct nf_hook_ops ipv6_defrag_ops[] = {
78 {
79 .hook = ipv6_defrag,
80 .pf = NFPROTO_IPV6,
81 .hooknum = NF_INET_PRE_ROUTING,
82 .priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
83 },
84 {
85 .hook = ipv6_defrag,
86 .pf = NFPROTO_IPV6,
87 .hooknum = NF_INET_LOCAL_OUT,
88 .priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
89 },
90};
91
92static void __net_exit defrag6_net_exit(struct net *net)
93{
94 struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
95
96 if (nf_frag->users) {
97 nf_unregister_net_hooks(net, ipv6_defrag_ops,
98 ARRAY_SIZE(ipv6_defrag_ops));
99 nf_frag->users = 0;
100 }
101}
102
103static struct pernet_operations defrag6_net_ops = {
104 .exit = defrag6_net_exit,
105};
106
107static int __init nf_defrag_init(void)
108{
109 int ret = 0;
110
111 ret = nf_ct_frag6_init();
112 if (ret < 0) {
113 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
114 return ret;
115 }
116 ret = register_pernet_subsys(&defrag6_net_ops);
117 if (ret < 0) {
118 pr_err("nf_defrag_ipv6: can't register pernet ops\n");
119 goto cleanup_frag6;
120 }
121 return ret;
122
123cleanup_frag6:
124 nf_ct_frag6_cleanup();
125 return ret;
126
127}
128
129static void __exit nf_defrag_fini(void)
130{
131 unregister_pernet_subsys(&defrag6_net_ops);
132 nf_ct_frag6_cleanup();
133}
134
135int nf_defrag_ipv6_enable(struct net *net)
136{
137 struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
138 int err = 0;
139
140 mutex_lock(&defrag6_mutex);
141 if (nf_frag->users == UINT_MAX) {
142 err = -EOVERFLOW;
143 goto out_unlock;
144 }
145
146 if (nf_frag->users) {
147 nf_frag->users++;
148 goto out_unlock;
149 }
150
151 err = nf_register_net_hooks(net, ipv6_defrag_ops,
152 ARRAY_SIZE(ipv6_defrag_ops));
153 if (err == 0)
154 nf_frag->users = 1;
155
156 out_unlock:
157 mutex_unlock(&defrag6_mutex);
158 return err;
159}
160EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
161
162void nf_defrag_ipv6_disable(struct net *net)
163{
164 struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
165
166 mutex_lock(&defrag6_mutex);
167 if (nf_frag->users) {
168 nf_frag->users--;
169 if (nf_frag->users == 0)
170 nf_unregister_net_hooks(net, ipv6_defrag_ops,
171 ARRAY_SIZE(ipv6_defrag_ops));
172 }
173 mutex_unlock(&defrag6_mutex);
174}
175EXPORT_SYMBOL_GPL(nf_defrag_ipv6_disable);
176
177module_init(nf_defrag_init);
178module_exit(nf_defrag_fini);
179
180MODULE_LICENSE("GPL");
181
