1 // SPDX-License-Identifier: GPL-2.0-only
2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 */
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
28 static DEFINE_MUTEX(defrag6_mutex);
29
nf_ct6_defrag_user(unsigned int hooknum,struct sk_buff * skb)30 static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
31 struct sk_buff *skb)
32 {
33 u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
34 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
35 if (skb_nfct(skb)) {
36 enum ip_conntrack_info ctinfo;
37 const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
38
39 zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
40 }
41 #endif
42 if (nf_bridge_in_prerouting(skb))
43 return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;
44
45 if (hooknum == NF_INET_PRE_ROUTING)
46 return IP6_DEFRAG_CONNTRACK_IN + zone_id;
47 else
48 return IP6_DEFRAG_CONNTRACK_OUT + zone_id;
49 }
50
ipv6_defrag(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)51 static unsigned int ipv6_defrag(void *priv,
52 struct sk_buff *skb,
53 const struct nf_hook_state *state)
54 {
55 int err;
56
57 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
58 /* Previously seen (loopback)? */
59 if (skb_nfct(skb) && !nf_ct_is_template((struct nf_conn *)skb_nfct(skb)))
60 return NF_ACCEPT;
61
62 if (skb->_nfct == IP_CT_UNTRACKED)
63 return NF_ACCEPT;
64 #endif
65
66 err = nf_ct_frag6_gather(state->net, skb,
67 nf_ct6_defrag_user(state->hook, skb));
68 /* queued */
69 if (err == -EINPROGRESS)
70 return NF_STOLEN;
71
72 return err == 0 ? NF_ACCEPT : NF_DROP;
73 }
74
75 static const struct nf_hook_ops ipv6_defrag_ops[] = {
76 {
77 .hook = ipv6_defrag,
78 .pf = NFPROTO_IPV6,
79 .hooknum = NF_INET_PRE_ROUTING,
80 .priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
81 },
82 {
83 .hook = ipv6_defrag,
84 .pf = NFPROTO_IPV6,
85 .hooknum = NF_INET_LOCAL_OUT,
86 .priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
87 },
88 };
89
defrag6_net_exit(struct net * net)90 static void __net_exit defrag6_net_exit(struct net *net)
91 {
92 if (net->nf.defrag_ipv6_users) {
93 nf_unregister_net_hooks(net, ipv6_defrag_ops,
94 ARRAY_SIZE(ipv6_defrag_ops));
95 net->nf.defrag_ipv6_users = 0;
96 }
97 }
98
99 static struct pernet_operations defrag6_net_ops = {
100 .exit = defrag6_net_exit,
101 };
102
nf_defrag_init(void)103 static int __init nf_defrag_init(void)
104 {
105 int ret = 0;
106
107 ret = nf_ct_frag6_init();
108 if (ret < 0) {
109 pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
110 return ret;
111 }
112 ret = register_pernet_subsys(&defrag6_net_ops);
113 if (ret < 0) {
114 pr_err("nf_defrag_ipv6: can't register pernet ops\n");
115 goto cleanup_frag6;
116 }
117 return ret;
118
119 cleanup_frag6:
120 nf_ct_frag6_cleanup();
121 return ret;
122
123 }
124
nf_defrag_fini(void)125 static void __exit nf_defrag_fini(void)
126 {
127 unregister_pernet_subsys(&defrag6_net_ops);
128 nf_ct_frag6_cleanup();
129 }
130
nf_defrag_ipv6_enable(struct net * net)131 int nf_defrag_ipv6_enable(struct net *net)
132 {
133 int err = 0;
134
135 mutex_lock(&defrag6_mutex);
136 if (net->nf.defrag_ipv6_users == UINT_MAX) {
137 err = -EOVERFLOW;
138 goto out_unlock;
139 }
140
141 if (net->nf.defrag_ipv6_users) {
142 net->nf.defrag_ipv6_users++;
143 goto out_unlock;
144 }
145
146 err = nf_register_net_hooks(net, ipv6_defrag_ops,
147 ARRAY_SIZE(ipv6_defrag_ops));
148 if (err == 0)
149 net->nf.defrag_ipv6_users = 1;
150
151 out_unlock:
152 mutex_unlock(&defrag6_mutex);
153 return err;
154 }
155 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
156
nf_defrag_ipv6_disable(struct net * net)157 void nf_defrag_ipv6_disable(struct net *net)
158 {
159 mutex_lock(&defrag6_mutex);
160 if (net->nf.defrag_ipv6_users) {
161 net->nf.defrag_ipv6_users--;
162 if (net->nf.defrag_ipv6_users == 0)
163 nf_unregister_net_hooks(net, ipv6_defrag_ops,
164 ARRAY_SIZE(ipv6_defrag_ops));
165 }
166 mutex_unlock(&defrag6_mutex);
167 }
168 EXPORT_SYMBOL_GPL(nf_defrag_ipv6_disable);
169
170 module_init(nf_defrag_init);
171 module_exit(nf_defrag_fini);
172
173 MODULE_LICENSE("GPL");
174