Yasuyuki Kozakai | a89ecb6 | 2006-04-01 02:22:54 -0800 | [diff] [blame] | 1 | /* Kernel module to match one of a list of TCP/UDP ports: ports are in |
| 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 | { |
| 163 | /* Must specify proto == TCP/UDP, no unknown flags or bad count */ |
| 164 | return (proto == IPPROTO_TCP || proto == IPPROTO_UDP) |
| 165 | && !(ip_invflags & XT_INV_PROTO) |
| 166 | && (match_flags == XT_MULTIPORT_SOURCE |
| 167 | || match_flags == XT_MULTIPORT_DESTINATION |
| 168 | || match_flags == XT_MULTIPORT_EITHER) |
| 169 | && count <= XT_MULTI_PORTS; |
| 170 | } |
| 171 | |
| 172 | /* Called when user tries to insert an entry of this type. */ |
| 173 | static int |
| 174 | checkentry(const char *tablename, |
| 175 | const void *info, |
| 176 | const struct xt_match *match, |
| 177 | void *matchinfo, |
| 178 | unsigned int matchsize, |
| 179 | unsigned int hook_mask) |
| 180 | { |
| 181 | const struct ipt_ip *ip = info; |
| 182 | const struct xt_multiport *multiinfo = matchinfo; |
| 183 | |
| 184 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 185 | multiinfo->count); |
| 186 | } |
| 187 | |
| 188 | static int |
| 189 | checkentry_v1(const char *tablename, |
| 190 | const void *info, |
| 191 | const struct xt_match *match, |
| 192 | void *matchinfo, |
| 193 | unsigned int matchsize, |
| 194 | unsigned int hook_mask) |
| 195 | { |
| 196 | const struct ipt_ip *ip = info; |
| 197 | const struct xt_multiport_v1 *multiinfo = matchinfo; |
| 198 | |
| 199 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 200 | multiinfo->count); |
| 201 | } |
| 202 | |
| 203 | static int |
| 204 | checkentry6(const char *tablename, |
| 205 | const void *info, |
| 206 | const struct xt_match *match, |
| 207 | void *matchinfo, |
| 208 | unsigned int matchsize, |
| 209 | unsigned int hook_mask) |
| 210 | { |
| 211 | const struct ip6t_ip6 *ip = info; |
| 212 | const struct xt_multiport *multiinfo = matchinfo; |
| 213 | |
| 214 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 215 | multiinfo->count); |
| 216 | } |
| 217 | |
| 218 | static int |
| 219 | checkentry6_v1(const char *tablename, |
| 220 | const void *info, |
| 221 | const struct xt_match *match, |
| 222 | void *matchinfo, |
| 223 | unsigned int matchsize, |
| 224 | unsigned int hook_mask) |
| 225 | { |
| 226 | const struct ip6t_ip6 *ip = info; |
| 227 | const struct xt_multiport_v1 *multiinfo = matchinfo; |
| 228 | |
| 229 | return check(ip->proto, ip->invflags, multiinfo->flags, |
| 230 | multiinfo->count); |
| 231 | } |
| 232 | |
| 233 | static struct xt_match multiport_match = { |
| 234 | .name = "multiport", |
| 235 | .revision = 0, |
| 236 | .matchsize = sizeof(struct xt_multiport), |
| 237 | .match = &match, |
| 238 | .checkentry = &checkentry, |
| 239 | .family = AF_INET, |
| 240 | .me = THIS_MODULE, |
| 241 | }; |
| 242 | |
| 243 | static struct xt_match multiport_match_v1 = { |
| 244 | .name = "multiport", |
| 245 | .revision = 1, |
| 246 | .matchsize = sizeof(struct xt_multiport_v1), |
| 247 | .match = &match_v1, |
| 248 | .checkentry = &checkentry_v1, |
| 249 | .family = AF_INET, |
| 250 | .me = THIS_MODULE, |
| 251 | }; |
| 252 | |
| 253 | static struct xt_match multiport6_match = { |
| 254 | .name = "multiport", |
| 255 | .revision = 0, |
| 256 | .matchsize = sizeof(struct xt_multiport), |
| 257 | .match = &match, |
| 258 | .checkentry = &checkentry6, |
| 259 | .family = AF_INET6, |
| 260 | .me = THIS_MODULE, |
| 261 | }; |
| 262 | |
| 263 | static struct xt_match multiport6_match_v1 = { |
| 264 | .name = "multiport", |
| 265 | .revision = 1, |
| 266 | .matchsize = sizeof(struct xt_multiport_v1), |
| 267 | .match = &match_v1, |
| 268 | .checkentry = &checkentry6_v1, |
| 269 | .family = AF_INET6, |
| 270 | .me = THIS_MODULE, |
| 271 | }; |
| 272 | |
| 273 | static int __init xt_multiport_init(void) |
| 274 | { |
| 275 | int ret; |
| 276 | |
| 277 | ret = xt_register_match(&multiport_match); |
| 278 | if (ret) |
| 279 | goto out; |
| 280 | |
| 281 | ret = xt_register_match(&multiport_match_v1); |
| 282 | if (ret) |
| 283 | goto out_unreg_multi_v0; |
| 284 | |
| 285 | ret = xt_register_match(&multiport6_match); |
| 286 | if (ret) |
| 287 | goto out_unreg_multi_v1; |
| 288 | |
| 289 | ret = xt_register_match(&multiport6_match_v1); |
| 290 | if (ret) |
| 291 | goto out_unreg_multi6_v0; |
| 292 | |
| 293 | return ret; |
| 294 | |
| 295 | out_unreg_multi6_v0: |
| 296 | xt_unregister_match(&multiport6_match); |
| 297 | out_unreg_multi_v1: |
| 298 | xt_unregister_match(&multiport_match_v1); |
| 299 | out_unreg_multi_v0: |
| 300 | xt_unregister_match(&multiport_match); |
| 301 | out: |
| 302 | return ret; |
| 303 | } |
| 304 | |
| 305 | static void __exit xt_multiport_fini(void) |
| 306 | { |
| 307 | xt_unregister_match(&multiport_match); |
| 308 | xt_unregister_match(&multiport_match_v1); |
| 309 | xt_unregister_match(&multiport6_match); |
| 310 | xt_unregister_match(&multiport6_match_v1); |
| 311 | } |
| 312 | |
| 313 | module_init(xt_multiport_init); |
| 314 | module_exit(xt_multiport_fini); |