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73e4022f KK |
1 | /* (C) 1999-2001 Paul `Rusty' Russell |
2 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
3 | * | |
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. | |
7 | */ | |
8 | ||
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> | |
834184b1 | 14 | #include <net/netns/generic.h> |
73e4022f KK |
15 | #include <net/route.h> |
16 | #include <net/ip.h> | |
17 | ||
8fa9ff68 | 18 | #include <linux/netfilter_bridge.h> |
73e4022f KK |
19 | #include <linux/netfilter_ipv4.h> |
20 | #include <net/netfilter/ipv4/nf_defrag_ipv4.h> | |
24de3d37 | 21 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
76780373 | 22 | #include <net/netfilter/nf_conntrack.h> |
37ee3d5b PM |
23 | #endif |
24 | #include <net/netfilter/nf_conntrack_zones.h> | |
73e4022f | 25 | |
834184b1 FW |
26 | static DEFINE_MUTEX(defrag4_mutex); |
27 | ||
19bcf9f2 EB |
28 | static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb, |
29 | u_int32_t user) | |
73e4022f KK |
30 | { |
31 | int err; | |
32 | ||
73e4022f | 33 | local_bh_disable(); |
19bcf9f2 | 34 | err = ip_defrag(net, skb, user); |
73e4022f KK |
35 | local_bh_enable(); |
36 | ||
5f547391 | 37 | if (!err) |
60ff7467 | 38 | skb->ignore_df = 1; |
73e4022f KK |
39 | |
40 | return err; | |
41 | } | |
42 | ||
8fa9ff68 PM |
43 | static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum, |
44 | struct sk_buff *skb) | |
45 | { | |
308ac914 | 46 | u16 zone_id = NF_CT_DEFAULT_ZONE_ID; |
24de3d37 | 47 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
cb9c6836 | 48 | if (skb_nfct(skb)) { |
deedb590 DB |
49 | enum ip_conntrack_info ctinfo; |
50 | const struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
51 | ||
52 | zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo)); | |
53 | } | |
37ee3d5b | 54 | #endif |
72b1e5e4 | 55 | if (nf_bridge_in_prerouting(skb)) |
308ac914 | 56 | return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id; |
72b1e5e4 | 57 | |
8fa9ff68 | 58 | if (hooknum == NF_INET_PRE_ROUTING) |
308ac914 | 59 | return IP_DEFRAG_CONNTRACK_IN + zone_id; |
8fa9ff68 | 60 | else |
308ac914 | 61 | return IP_DEFRAG_CONNTRACK_OUT + zone_id; |
8fa9ff68 PM |
62 | } |
63 | ||
06198b34 | 64 | static unsigned int ipv4_conntrack_defrag(void *priv, |
73e4022f | 65 | struct sk_buff *skb, |
238e54c9 | 66 | const struct nf_hook_state *state) |
73e4022f | 67 | { |
cbdd769a | 68 | struct sock *sk = skb->sk; |
7b2ff18e | 69 | |
f668f5f7 ED |
70 | if (sk && sk_fullsock(sk) && (sk->sk_family == PF_INET) && |
71 | inet_sk(sk)->nodefrag) | |
7b2ff18e JO |
72 | return NF_ACCEPT; |
73 | ||
24de3d37 DJ |
74 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
75 | #if !IS_ENABLED(CONFIG_NF_NAT) | |
73e4022f KK |
76 | /* Previously seen (loopback)? Ignore. Do this before |
77 | fragment check. */ | |
cb9c6836 | 78 | if (skb_nfct(skb) && !nf_ct_is_template((struct nf_conn *)skb_nfct(skb))) |
73e4022f KK |
79 | return NF_ACCEPT; |
80 | #endif | |
41e4b391 AB |
81 | if (skb->_nfct == IP_CT_UNTRACKED) |
82 | return NF_ACCEPT; | |
38f7ac3e | 83 | #endif |
73e4022f | 84 | /* Gather fragments. */ |
41e4b391 | 85 | if (ip_is_fragment(ip_hdr(skb))) { |
795aa6ef | 86 | enum ip_defrag_users user = |
082a758f | 87 | nf_ct_defrag_user(state->hook, skb); |
795aa6ef | 88 | |
19bcf9f2 | 89 | if (nf_ct_ipv4_gather_frags(state->net, skb, user)) |
73e4022f KK |
90 | return NF_STOLEN; |
91 | } | |
92 | return NF_ACCEPT; | |
93 | } | |
94 | ||
591bb278 | 95 | static const struct nf_hook_ops ipv4_defrag_ops[] = { |
73e4022f KK |
96 | { |
97 | .hook = ipv4_conntrack_defrag, | |
89a48e35 | 98 | .pf = NFPROTO_IPV4, |
73e4022f KK |
99 | .hooknum = NF_INET_PRE_ROUTING, |
100 | .priority = NF_IP_PRI_CONNTRACK_DEFRAG, | |
101 | }, | |
102 | { | |
103 | .hook = ipv4_conntrack_defrag, | |
89a48e35 | 104 | .pf = NFPROTO_IPV4, |
73e4022f KK |
105 | .hooknum = NF_INET_LOCAL_OUT, |
106 | .priority = NF_IP_PRI_CONNTRACK_DEFRAG, | |
107 | }, | |
108 | }; | |
109 | ||
834184b1 FW |
110 | static void __net_exit defrag4_net_exit(struct net *net) |
111 | { | |
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; | |
116 | } | |
117 | } | |
118 | ||
119 | static struct pernet_operations defrag4_net_ops = { | |
120 | .exit = defrag4_net_exit, | |
121 | }; | |
122 | ||
73e4022f KK |
123 | static int __init nf_defrag_init(void) |
124 | { | |
834184b1 | 125 | return register_pernet_subsys(&defrag4_net_ops); |
73e4022f KK |
126 | } |
127 | ||
128 | static void __exit nf_defrag_fini(void) | |
129 | { | |
834184b1 | 130 | unregister_pernet_subsys(&defrag4_net_ops); |
73e4022f KK |
131 | } |
132 | ||
834184b1 | 133 | int nf_defrag_ipv4_enable(struct net *net) |
73e4022f | 134 | { |
834184b1 FW |
135 | int err = 0; |
136 | ||
137 | might_sleep(); | |
138 | ||
139 | if (net->nf.defrag_ipv4) | |
140 | return 0; | |
141 | ||
142 | mutex_lock(&defrag4_mutex); | |
143 | if (net->nf.defrag_ipv4) | |
144 | goto out_unlock; | |
145 | ||
146 | err = nf_register_net_hooks(net, ipv4_defrag_ops, | |
147 | ARRAY_SIZE(ipv4_defrag_ops)); | |
148 | if (err == 0) | |
149 | net->nf.defrag_ipv4 = true; | |
150 | ||
151 | out_unlock: | |
152 | mutex_unlock(&defrag4_mutex); | |
153 | return err; | |
73e4022f KK |
154 | } |
155 | EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable); | |
156 | ||
157 | module_init(nf_defrag_init); | |
158 | module_exit(nf_defrag_fini); | |
159 | ||
160 | MODULE_LICENSE("GPL"); |