Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* Kernel module to match connection tracking information. |
2 | * Superset of Rusty's minimalistic state match. | |
3 | * | |
4 | * (C) 2001 Marc Boucher (marc@mbsi.ca). | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/skbuff.h> | |
2e4e6a17 HW |
13 | #include <linux/netfilter/x_tables.h> |
14 | #include <linux/netfilter/xt_conntrack.h> | |
587aa641 | 15 | #include <net/netfilter/nf_conntrack.h> |
1da177e4 LT |
16 | |
17 | MODULE_LICENSE("GPL"); | |
18 | MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>"); | |
19 | MODULE_DESCRIPTION("iptables connection tracking match module"); | |
2e4e6a17 | 20 | MODULE_ALIAS("ipt_conntrack"); |
1da177e4 | 21 | |
1d93a9cb | 22 | static bool |
d3c5ee6d JE |
23 | conntrack_mt(const struct sk_buff *skb, const struct net_device *in, |
24 | const struct net_device *out, const struct xt_match *match, | |
25 | const void *matchinfo, int offset, unsigned int protoff, | |
26 | bool *hotdrop) | |
9fb9cbb1 | 27 | { |
2e4e6a17 | 28 | const struct xt_conntrack_info *sinfo = matchinfo; |
a47362a2 | 29 | const struct nf_conn *ct; |
9fb9cbb1 YK |
30 | enum ip_conntrack_info ctinfo; |
31 | unsigned int statebit; | |
32 | ||
a47362a2 | 33 | ct = nf_ct_get(skb, &ctinfo); |
9fb9cbb1 | 34 | |
e79ec50b | 35 | #define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg))) |
9fb9cbb1 YK |
36 | |
37 | if (ct == &nf_conntrack_untracked) | |
2e4e6a17 | 38 | statebit = XT_CONNTRACK_STATE_UNTRACKED; |
9fb9cbb1 | 39 | else if (ct) |
601e68e1 YH |
40 | statebit = XT_CONNTRACK_STATE_BIT(ctinfo); |
41 | else | |
42 | statebit = XT_CONNTRACK_STATE_INVALID; | |
43 | ||
50b9f1d5 | 44 | if (sinfo->flags & XT_CONNTRACK_STATE) { |
9fb9cbb1 | 45 | if (ct) { |
50b9f1d5 | 46 | if (test_bit(IPS_SRC_NAT_BIT, &ct->status)) |
2e4e6a17 | 47 | statebit |= XT_CONNTRACK_STATE_SNAT; |
50b9f1d5 | 48 | if (test_bit(IPS_DST_NAT_BIT, &ct->status)) |
2e4e6a17 | 49 | statebit |= XT_CONNTRACK_STATE_DNAT; |
9fb9cbb1 | 50 | } |
50b9f1d5 PM |
51 | if (FWINV((statebit & sinfo->statemask) == 0, |
52 | XT_CONNTRACK_STATE)) | |
1d93a9cb | 53 | return false; |
9fb9cbb1 YK |
54 | } |
55 | ||
50b9f1d5 PM |
56 | if (ct == NULL) { |
57 | if (sinfo->flags & ~XT_CONNTRACK_STATE) | |
1d93a9cb JE |
58 | return false; |
59 | return true; | |
9fb9cbb1 YK |
60 | } |
61 | ||
50b9f1d5 PM |
62 | if (sinfo->flags & XT_CONNTRACK_PROTO && |
63 | FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum != | |
601e68e1 | 64 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum, |
50b9f1d5 | 65 | XT_CONNTRACK_PROTO)) |
1d93a9cb | 66 | return false; |
50b9f1d5 PM |
67 | |
68 | if (sinfo->flags & XT_CONNTRACK_ORIGSRC && | |
69 | FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip & | |
601e68e1 | 70 | sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) != |
50b9f1d5 PM |
71 | sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip, |
72 | XT_CONNTRACK_ORIGSRC)) | |
1d93a9cb | 73 | return false; |
9fb9cbb1 | 74 | |
50b9f1d5 PM |
75 | if (sinfo->flags & XT_CONNTRACK_ORIGDST && |
76 | FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip & | |
601e68e1 | 77 | sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) != |
50b9f1d5 PM |
78 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip, |
79 | XT_CONNTRACK_ORIGDST)) | |
1d93a9cb | 80 | return false; |
9fb9cbb1 | 81 | |
50b9f1d5 PM |
82 | if (sinfo->flags & XT_CONNTRACK_REPLSRC && |
83 | FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip & | |
601e68e1 | 84 | sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) != |
50b9f1d5 PM |
85 | sinfo->tuple[IP_CT_DIR_REPLY].src.ip, |
86 | XT_CONNTRACK_REPLSRC)) | |
1d93a9cb | 87 | return false; |
9fb9cbb1 | 88 | |
50b9f1d5 PM |
89 | if (sinfo->flags & XT_CONNTRACK_REPLDST && |
90 | FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip & | |
601e68e1 | 91 | sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) != |
50b9f1d5 PM |
92 | sinfo->tuple[IP_CT_DIR_REPLY].dst.ip, |
93 | XT_CONNTRACK_REPLDST)) | |
1d93a9cb | 94 | return false; |
9fb9cbb1 | 95 | |
50b9f1d5 PM |
96 | if (sinfo->flags & XT_CONNTRACK_STATUS && |
97 | FWINV((ct->status & sinfo->statusmask) == 0, | |
601e68e1 | 98 | XT_CONNTRACK_STATUS)) |
1d93a9cb | 99 | return false; |
9fb9cbb1 | 100 | |
50b9f1d5 PM |
101 | if(sinfo->flags & XT_CONNTRACK_EXPIRES) { |
102 | unsigned long expires = timer_pending(&ct->timeout) ? | |
103 | (ct->timeout.expires - jiffies)/HZ : 0; | |
9fb9cbb1 | 104 | |
50b9f1d5 PM |
105 | if (FWINV(!(expires >= sinfo->expires_min && |
106 | expires <= sinfo->expires_max), | |
107 | XT_CONNTRACK_EXPIRES)) | |
1d93a9cb | 108 | return false; |
9fb9cbb1 | 109 | } |
1d93a9cb | 110 | return true; |
e79ec50b | 111 | #undef FWINV |
9fb9cbb1 YK |
112 | } |
113 | ||
ccb79bdc | 114 | static bool |
d3c5ee6d JE |
115 | conntrack_mt_check(const char *tablename, const void *ip, |
116 | const struct xt_match *match, void *matchinfo, | |
117 | unsigned int hook_mask) | |
b9f78f9f | 118 | { |
b9f78f9f | 119 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
fe0b9294 | 120 | printk(KERN_WARNING "can't load conntrack support for " |
df54aae0 | 121 | "proto=%u\n", match->family); |
ccb79bdc | 122 | return false; |
b9f78f9f | 123 | } |
ccb79bdc | 124 | return true; |
b9f78f9f PNA |
125 | } |
126 | ||
d3c5ee6d JE |
127 | static void |
128 | conntrack_mt_destroy(const struct xt_match *match, void *matchinfo) | |
b9f78f9f | 129 | { |
b9f78f9f | 130 | nf_ct_l3proto_module_put(match->family); |
b9f78f9f PNA |
131 | } |
132 | ||
da0dd231 PM |
133 | #ifdef CONFIG_COMPAT |
134 | struct compat_xt_conntrack_info | |
135 | { | |
136 | compat_uint_t statemask; | |
137 | compat_uint_t statusmask; | |
138 | struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX]; | |
139 | struct in_addr sipmsk[IP_CT_DIR_MAX]; | |
140 | struct in_addr dipmsk[IP_CT_DIR_MAX]; | |
141 | compat_ulong_t expires_min; | |
142 | compat_ulong_t expires_max; | |
143 | u_int8_t flags; | |
144 | u_int8_t invflags; | |
145 | }; | |
146 | ||
d3c5ee6d | 147 | static void conntrack_mt_compat_from_user(void *dst, void *src) |
da0dd231 | 148 | { |
a47362a2 | 149 | const struct compat_xt_conntrack_info *cm = src; |
da0dd231 PM |
150 | struct xt_conntrack_info m = { |
151 | .statemask = cm->statemask, | |
152 | .statusmask = cm->statusmask, | |
153 | .expires_min = cm->expires_min, | |
154 | .expires_max = cm->expires_max, | |
155 | .flags = cm->flags, | |
156 | .invflags = cm->invflags, | |
157 | }; | |
158 | memcpy(m.tuple, cm->tuple, sizeof(m.tuple)); | |
159 | memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk)); | |
160 | memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk)); | |
161 | memcpy(dst, &m, sizeof(m)); | |
162 | } | |
163 | ||
d3c5ee6d | 164 | static int conntrack_mt_compat_to_user(void __user *dst, void *src) |
da0dd231 | 165 | { |
a47362a2 | 166 | const struct xt_conntrack_info *m = src; |
da0dd231 PM |
167 | struct compat_xt_conntrack_info cm = { |
168 | .statemask = m->statemask, | |
169 | .statusmask = m->statusmask, | |
170 | .expires_min = m->expires_min, | |
171 | .expires_max = m->expires_max, | |
172 | .flags = m->flags, | |
173 | .invflags = m->invflags, | |
174 | }; | |
175 | memcpy(cm.tuple, m->tuple, sizeof(cm.tuple)); | |
176 | memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk)); | |
177 | memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk)); | |
178 | return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; | |
179 | } | |
180 | #endif | |
181 | ||
d3c5ee6d | 182 | static struct xt_match conntrack_mt_reg __read_mostly = { |
1da177e4 | 183 | .name = "conntrack", |
d3c5ee6d JE |
184 | .match = conntrack_mt, |
185 | .checkentry = conntrack_mt_check, | |
186 | .destroy = conntrack_mt_destroy, | |
5d04bff0 | 187 | .matchsize = sizeof(struct xt_conntrack_info), |
da0dd231 PM |
188 | #ifdef CONFIG_COMPAT |
189 | .compatsize = sizeof(struct compat_xt_conntrack_info), | |
d3c5ee6d JE |
190 | .compat_from_user = conntrack_mt_compat_from_user, |
191 | .compat_to_user = conntrack_mt_compat_to_user, | |
da0dd231 | 192 | #endif |
a45049c5 | 193 | .family = AF_INET, |
1da177e4 LT |
194 | .me = THIS_MODULE, |
195 | }; | |
196 | ||
d3c5ee6d | 197 | static int __init conntrack_mt_init(void) |
1da177e4 | 198 | { |
d3c5ee6d | 199 | return xt_register_match(&conntrack_mt_reg); |
1da177e4 LT |
200 | } |
201 | ||
d3c5ee6d | 202 | static void __exit conntrack_mt_exit(void) |
1da177e4 | 203 | { |
d3c5ee6d | 204 | xt_unregister_match(&conntrack_mt_reg); |
1da177e4 LT |
205 | } |
206 | ||
d3c5ee6d JE |
207 | module_init(conntrack_mt_init); |
208 | module_exit(conntrack_mt_exit); |