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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> | |
14 | #include <net/route.h> | |
15 | #include <net/ip.h> | |
16 | ||
8fa9ff68 | 17 | #include <linux/netfilter_bridge.h> |
73e4022f KK |
18 | #include <linux/netfilter_ipv4.h> |
19 | #include <net/netfilter/ipv4/nf_defrag_ipv4.h> | |
24de3d37 | 20 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
76780373 | 21 | #include <net/netfilter/nf_conntrack.h> |
37ee3d5b PM |
22 | #endif |
23 | #include <net/netfilter/nf_conntrack_zones.h> | |
73e4022f | 24 | |
19bcf9f2 EB |
25 | static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb, |
26 | u_int32_t user) | |
73e4022f KK |
27 | { |
28 | int err; | |
29 | ||
73e4022f | 30 | local_bh_disable(); |
19bcf9f2 | 31 | err = ip_defrag(net, skb, user); |
73e4022f KK |
32 | local_bh_enable(); |
33 | ||
5f547391 | 34 | if (!err) |
60ff7467 | 35 | skb->ignore_df = 1; |
73e4022f KK |
36 | |
37 | return err; | |
38 | } | |
39 | ||
8fa9ff68 PM |
40 | static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum, |
41 | struct sk_buff *skb) | |
42 | { | |
308ac914 | 43 | u16 zone_id = NF_CT_DEFAULT_ZONE_ID; |
24de3d37 | 44 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
deedb590 DB |
45 | if (skb->nfct) { |
46 | enum ip_conntrack_info ctinfo; | |
47 | const struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
48 | ||
49 | zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo)); | |
50 | } | |
37ee3d5b | 51 | #endif |
72b1e5e4 | 52 | if (nf_bridge_in_prerouting(skb)) |
308ac914 | 53 | return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id; |
72b1e5e4 | 54 | |
8fa9ff68 | 55 | if (hooknum == NF_INET_PRE_ROUTING) |
308ac914 | 56 | return IP_DEFRAG_CONNTRACK_IN + zone_id; |
8fa9ff68 | 57 | else |
308ac914 | 58 | return IP_DEFRAG_CONNTRACK_OUT + zone_id; |
8fa9ff68 PM |
59 | } |
60 | ||
06198b34 | 61 | static unsigned int ipv4_conntrack_defrag(void *priv, |
73e4022f | 62 | struct sk_buff *skb, |
238e54c9 | 63 | const struct nf_hook_state *state) |
73e4022f | 64 | { |
cbdd769a | 65 | struct sock *sk = skb->sk; |
7b2ff18e | 66 | |
f668f5f7 ED |
67 | if (sk && sk_fullsock(sk) && (sk->sk_family == PF_INET) && |
68 | inet_sk(sk)->nodefrag) | |
7b2ff18e JO |
69 | return NF_ACCEPT; |
70 | ||
24de3d37 DJ |
71 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
72 | #if !IS_ENABLED(CONFIG_NF_NAT) | |
73e4022f KK |
73 | /* Previously seen (loopback)? Ignore. Do this before |
74 | fragment check. */ | |
b2a15a60 | 75 | if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct)) |
73e4022f KK |
76 | return NF_ACCEPT; |
77 | #endif | |
38f7ac3e | 78 | #endif |
73e4022f | 79 | /* Gather fragments. */ |
56f8a75c | 80 | if (ip_is_fragment(ip_hdr(skb))) { |
795aa6ef | 81 | enum ip_defrag_users user = |
082a758f | 82 | nf_ct_defrag_user(state->hook, skb); |
795aa6ef | 83 | |
19bcf9f2 | 84 | if (nf_ct_ipv4_gather_frags(state->net, skb, user)) |
73e4022f KK |
85 | return NF_STOLEN; |
86 | } | |
87 | return NF_ACCEPT; | |
88 | } | |
89 | ||
90 | static struct nf_hook_ops ipv4_defrag_ops[] = { | |
91 | { | |
92 | .hook = ipv4_conntrack_defrag, | |
89a48e35 | 93 | .pf = NFPROTO_IPV4, |
73e4022f KK |
94 | .hooknum = NF_INET_PRE_ROUTING, |
95 | .priority = NF_IP_PRI_CONNTRACK_DEFRAG, | |
96 | }, | |
97 | { | |
98 | .hook = ipv4_conntrack_defrag, | |
89a48e35 | 99 | .pf = NFPROTO_IPV4, |
73e4022f KK |
100 | .hooknum = NF_INET_LOCAL_OUT, |
101 | .priority = NF_IP_PRI_CONNTRACK_DEFRAG, | |
102 | }, | |
103 | }; | |
104 | ||
105 | static int __init nf_defrag_init(void) | |
106 | { | |
107 | return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops)); | |
108 | } | |
109 | ||
110 | static void __exit nf_defrag_fini(void) | |
111 | { | |
112 | nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops)); | |
113 | } | |
114 | ||
115 | void nf_defrag_ipv4_enable(void) | |
116 | { | |
117 | } | |
118 | EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable); | |
119 | ||
120 | module_init(nf_defrag_init); | |
121 | module_exit(nf_defrag_fini); | |
122 | ||
123 | MODULE_LICENSE("GPL"); |