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957dc80a | 1 | /* Kernel module to match one of a list of TCP/UDP/SCTP/DCCP ports: ports are in |
a89ecb6a YK |
2 | the same place so we can treat them as equal. */ |
3 | ||
4 | /* (C) 1999-2001 Paul `Rusty' Russell | |
5 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/types.h> | |
14 | #include <linux/udp.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/in.h> | |
17 | ||
18 | #include <linux/netfilter/xt_multiport.h> | |
19 | #include <linux/netfilter/x_tables.h> | |
20 | #include <linux/netfilter_ipv4/ip_tables.h> | |
21 | #include <linux/netfilter_ipv6/ip6_tables.h> | |
22 | ||
23 | MODULE_LICENSE("GPL"); | |
24 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
25 | MODULE_DESCRIPTION("x_tables multiple port match module"); | |
26 | MODULE_ALIAS("ipt_multiport"); | |
27 | MODULE_ALIAS("ip6t_multiport"); | |
28 | ||
29 | #if 0 | |
30 | #define duprintf(format, args...) printk(format , ## args) | |
31 | #else | |
32 | #define duprintf(format, args...) | |
33 | #endif | |
34 | ||
35 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ | |
36 | static inline int | |
37 | ports_match(const u_int16_t *portlist, enum xt_multiport_flags flags, | |
38 | u_int8_t count, u_int16_t src, u_int16_t dst) | |
39 | { | |
40 | unsigned int i; | |
41 | for (i = 0; i < count; i++) { | |
42 | if (flags != XT_MULTIPORT_DESTINATION && portlist[i] == src) | |
43 | return 1; | |
44 | ||
45 | if (flags != XT_MULTIPORT_SOURCE && portlist[i] == dst) | |
46 | return 1; | |
47 | } | |
48 | ||
49 | return 0; | |
50 | } | |
51 | ||
52 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ | |
53 | static inline int | |
54 | ports_match_v1(const struct xt_multiport_v1 *minfo, | |
55 | u_int16_t src, u_int16_t dst) | |
56 | { | |
57 | unsigned int i; | |
58 | u_int16_t s, e; | |
59 | ||
60 | for (i = 0; i < minfo->count; i++) { | |
61 | s = minfo->ports[i]; | |
62 | ||
63 | if (minfo->pflags[i]) { | |
64 | /* range port matching */ | |
65 | e = minfo->ports[++i]; | |
66 | duprintf("src or dst matches with %d-%d?\n", s, e); | |
67 | ||
68 | if (minfo->flags == XT_MULTIPORT_SOURCE | |
69 | && src >= s && src <= e) | |
70 | return 1 ^ minfo->invert; | |
71 | if (minfo->flags == XT_MULTIPORT_DESTINATION | |
72 | && dst >= s && dst <= e) | |
73 | return 1 ^ minfo->invert; | |
74 | if (minfo->flags == XT_MULTIPORT_EITHER | |
75 | && ((dst >= s && dst <= e) | |
76 | || (src >= s && src <= e))) | |
77 | return 1 ^ minfo->invert; | |
78 | } else { | |
79 | /* exact port matching */ | |
80 | duprintf("src or dst matches with %d?\n", s); | |
81 | ||
82 | if (minfo->flags == XT_MULTIPORT_SOURCE | |
83 | && src == s) | |
84 | return 1 ^ minfo->invert; | |
85 | if (minfo->flags == XT_MULTIPORT_DESTINATION | |
86 | && dst == s) | |
87 | return 1 ^ minfo->invert; | |
88 | if (minfo->flags == XT_MULTIPORT_EITHER | |
89 | && (src == s || dst == s)) | |
90 | return 1 ^ minfo->invert; | |
91 | } | |
92 | } | |
93 | ||
94 | return minfo->invert; | |
95 | } | |
96 | ||
97 | static int | |
98 | match(const struct sk_buff *skb, | |
99 | const struct net_device *in, | |
100 | const struct net_device *out, | |
101 | const struct xt_match *match, | |
102 | const void *matchinfo, | |
103 | int offset, | |
104 | unsigned int protoff, | |
105 | int *hotdrop) | |
106 | { | |
107 | u16 _ports[2], *pptr; | |
108 | const struct xt_multiport *multiinfo = matchinfo; | |
109 | ||
110 | if (offset) | |
111 | return 0; | |
112 | ||
113 | pptr = skb_header_pointer(skb, protoff, sizeof(_ports), _ports); | |
114 | if (pptr == NULL) { | |
115 | /* We've been asked to examine this packet, and we | |
116 | * can't. Hence, no choice but to drop. | |
117 | */ | |
118 | duprintf("xt_multiport: Dropping evil offset=0 tinygram.\n"); | |
119 | *hotdrop = 1; | |
120 | return 0; | |
121 | } | |
122 | ||
123 | return ports_match(multiinfo->ports, | |
124 | multiinfo->flags, multiinfo->count, | |
125 | ntohs(pptr[0]), ntohs(pptr[1])); | |
126 | } | |
127 | ||
128 | static int | |
129 | match_v1(const struct sk_buff *skb, | |
130 | const struct net_device *in, | |
131 | const struct net_device *out, | |
132 | const struct xt_match *match, | |
133 | const void *matchinfo, | |
134 | int offset, | |
135 | unsigned int protoff, | |
136 | int *hotdrop) | |
137 | { | |
138 | u16 _ports[2], *pptr; | |
139 | const struct xt_multiport_v1 *multiinfo = matchinfo; | |
140 | ||
141 | if (offset) | |
142 | return 0; | |
143 | ||
144 | pptr = skb_header_pointer(skb, protoff, sizeof(_ports), _ports); | |
145 | if (pptr == NULL) { | |
146 | /* We've been asked to examine this packet, and we | |
147 | * can't. Hence, no choice but to drop. | |
148 | */ | |
149 | duprintf("xt_multiport: Dropping evil offset=0 tinygram.\n"); | |
150 | *hotdrop = 1; | |
151 | return 0; | |
152 | } | |
153 | ||
154 | return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); | |
155 | } | |
156 | ||
157 | static inline int | |
158 | check(u_int16_t proto, | |
159 | u_int8_t ip_invflags, | |
160 | u_int8_t match_flags, | |
161 | u_int8_t count) | |
162 | { | |
957dc80a PM |
163 | /* Must specify supported protocol, no unknown flags or bad count */ |
164 | return (proto == IPPROTO_TCP || proto == IPPROTO_UDP | |
165 | || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) | |
a89ecb6a YK |
166 | && !(ip_invflags & XT_INV_PROTO) |
167 | && (match_flags == XT_MULTIPORT_SOURCE | |
168 | || match_flags == XT_MULTIPORT_DESTINATION | |
169 | || match_flags == XT_MULTIPORT_EITHER) | |
170 | && count <= XT_MULTI_PORTS; | |
171 | } | |
172 | ||
173 | /* Called when user tries to insert an entry of this type. */ | |
174 | static int | |
175 | checkentry(const char *tablename, | |
176 | const void *info, | |
177 | const struct xt_match *match, | |
178 | void *matchinfo, | |
179 | unsigned int matchsize, | |
180 | unsigned int hook_mask) | |
181 | { | |
182 | const struct ipt_ip *ip = info; | |
183 | const struct xt_multiport *multiinfo = matchinfo; | |
184 | ||
185 | return check(ip->proto, ip->invflags, multiinfo->flags, | |
186 | multiinfo->count); | |
187 | } | |
188 | ||
189 | static int | |
190 | checkentry_v1(const char *tablename, | |
191 | const void *info, | |
192 | const struct xt_match *match, | |
193 | void *matchinfo, | |
194 | unsigned int matchsize, | |
195 | unsigned int hook_mask) | |
196 | { | |
197 | const struct ipt_ip *ip = info; | |
198 | const struct xt_multiport_v1 *multiinfo = matchinfo; | |
199 | ||
200 | return check(ip->proto, ip->invflags, multiinfo->flags, | |
201 | multiinfo->count); | |
202 | } | |
203 | ||
204 | static int | |
205 | checkentry6(const char *tablename, | |
206 | const void *info, | |
207 | const struct xt_match *match, | |
208 | void *matchinfo, | |
209 | unsigned int matchsize, | |
210 | unsigned int hook_mask) | |
211 | { | |
212 | const struct ip6t_ip6 *ip = info; | |
213 | const struct xt_multiport *multiinfo = matchinfo; | |
214 | ||
215 | return check(ip->proto, ip->invflags, multiinfo->flags, | |
216 | multiinfo->count); | |
217 | } | |
218 | ||
219 | static int | |
220 | checkentry6_v1(const char *tablename, | |
221 | const void *info, | |
222 | const struct xt_match *match, | |
223 | void *matchinfo, | |
224 | unsigned int matchsize, | |
225 | unsigned int hook_mask) | |
226 | { | |
227 | const struct ip6t_ip6 *ip = info; | |
228 | const struct xt_multiport_v1 *multiinfo = matchinfo; | |
229 | ||
230 | return check(ip->proto, ip->invflags, multiinfo->flags, | |
231 | multiinfo->count); | |
232 | } | |
233 | ||
234 | static struct xt_match multiport_match = { | |
235 | .name = "multiport", | |
236 | .revision = 0, | |
237 | .matchsize = sizeof(struct xt_multiport), | |
238 | .match = &match, | |
239 | .checkentry = &checkentry, | |
240 | .family = AF_INET, | |
241 | .me = THIS_MODULE, | |
242 | }; | |
243 | ||
244 | static struct xt_match multiport_match_v1 = { | |
245 | .name = "multiport", | |
246 | .revision = 1, | |
247 | .matchsize = sizeof(struct xt_multiport_v1), | |
248 | .match = &match_v1, | |
249 | .checkentry = &checkentry_v1, | |
250 | .family = AF_INET, | |
251 | .me = THIS_MODULE, | |
252 | }; | |
253 | ||
254 | static struct xt_match multiport6_match = { | |
255 | .name = "multiport", | |
256 | .revision = 0, | |
257 | .matchsize = sizeof(struct xt_multiport), | |
258 | .match = &match, | |
259 | .checkentry = &checkentry6, | |
260 | .family = AF_INET6, | |
261 | .me = THIS_MODULE, | |
262 | }; | |
263 | ||
264 | static struct xt_match multiport6_match_v1 = { | |
265 | .name = "multiport", | |
266 | .revision = 1, | |
267 | .matchsize = sizeof(struct xt_multiport_v1), | |
268 | .match = &match_v1, | |
269 | .checkentry = &checkentry6_v1, | |
270 | .family = AF_INET6, | |
271 | .me = THIS_MODULE, | |
272 | }; | |
273 | ||
274 | static int __init xt_multiport_init(void) | |
275 | { | |
276 | int ret; | |
277 | ||
278 | ret = xt_register_match(&multiport_match); | |
279 | if (ret) | |
280 | goto out; | |
281 | ||
282 | ret = xt_register_match(&multiport_match_v1); | |
283 | if (ret) | |
284 | goto out_unreg_multi_v0; | |
285 | ||
286 | ret = xt_register_match(&multiport6_match); | |
287 | if (ret) | |
288 | goto out_unreg_multi_v1; | |
289 | ||
290 | ret = xt_register_match(&multiport6_match_v1); | |
291 | if (ret) | |
292 | goto out_unreg_multi6_v0; | |
293 | ||
294 | return ret; | |
295 | ||
296 | out_unreg_multi6_v0: | |
297 | xt_unregister_match(&multiport6_match); | |
298 | out_unreg_multi_v1: | |
299 | xt_unregister_match(&multiport_match_v1); | |
300 | out_unreg_multi_v0: | |
301 | xt_unregister_match(&multiport_match); | |
302 | out: | |
303 | return ret; | |
304 | } | |
305 | ||
306 | static void __exit xt_multiport_fini(void) | |
307 | { | |
308 | xt_unregister_match(&multiport_match); | |
309 | xt_unregister_match(&multiport_match_v1); | |
310 | xt_unregister_match(&multiport6_match); | |
311 | xt_unregister_match(&multiport6_match_v1); | |
312 | } | |
313 | ||
314 | module_init(xt_multiport_init); | |
315 | module_exit(xt_multiport_fini); |