1 /* Shared library add-on to iptables for DCCP matching
2 *
3 * (C) 2005 by Harald Welte <laforge@netfilter.org>
4 *
5 * This program is distributed under the terms of GNU GPL v2, 1991
6 *
7 */
8 #include <stdint.h>
9 #include <stdio.h>
10 #include <string.h>
11 #include <stdlib.h>
12 #include <netdb.h>
13 #include <arpa/inet.h>
14 #include <xtables.h>
15 #include <linux/dccp.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <linux/netfilter/xt_dccp.h>
18
19 #if 0
20 #define DEBUGP(format, first...) printf(format, ##first)
21 #define static
22 #else
23 #define DEBUGP(format, fist...)
24 #endif
25
26 enum {
27 O_SOURCE_PORT = 0,
28 O_DEST_PORT,
29 O_DCCP_TYPES,
30 O_DCCP_OPTION,
31 };
32
dccp_help(void)33 static void dccp_help(void)
34 {
35 printf(
36 "dccp match options\n"
37 "[!] --source-port port[:port] match source port(s)\n"
38 " --sport ...\n"
39 "[!] --destination-port port[:port] match destination port(s)\n"
40 " --dport ...\n");
41 }
42
43 #define s struct xt_dccp_info
44 static const struct xt_option_entry dccp_opts[] = {
45 {.name = "source-port", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,
46 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},
47 {.name = "sport", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,
48 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},
49 {.name = "destination-port", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,
50 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},
51 {.name = "dport", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,
52 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},
53 {.name = "dccp-types", .id = O_DCCP_TYPES, .type = XTTYPE_STRING},
54 {.name = "dccp-option", .id = O_DCCP_OPTION, .type = XTTYPE_UINT8,
55 .min = 1, .max = UINT8_MAX, .flags = XTOPT_PUT,
56 XTOPT_POINTER(s, option)},
57 XTOPT_TABLEEND,
58 };
59 #undef s
60
61 static const char *const dccp_pkt_types[] = {
62 [DCCP_PKT_REQUEST] = "REQUEST",
63 [DCCP_PKT_RESPONSE] = "RESPONSE",
64 [DCCP_PKT_DATA] = "DATA",
65 [DCCP_PKT_ACK] = "ACK",
66 [DCCP_PKT_DATAACK] = "DATAACK",
67 [DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
68 [DCCP_PKT_CLOSE] = "CLOSE",
69 [DCCP_PKT_RESET] = "RESET",
70 [DCCP_PKT_SYNC] = "SYNC",
71 [DCCP_PKT_SYNCACK] = "SYNCACK",
72 [DCCP_PKT_INVALID] = "INVALID",
73 };
74
75 static uint16_t
parse_dccp_types(const char * typestring)76 parse_dccp_types(const char *typestring)
77 {
78 uint16_t typemask = 0;
79 char *ptr, *buffer;
80
81 buffer = strdup(typestring);
82
83 for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
84 unsigned int i;
85 for (i = 0; i < ARRAY_SIZE(dccp_pkt_types); ++i)
86 if (!strcasecmp(dccp_pkt_types[i], ptr)) {
87 typemask |= (1 << i);
88 break;
89 }
90 if (i == ARRAY_SIZE(dccp_pkt_types))
91 xtables_error(PARAMETER_PROBLEM,
92 "Unknown DCCP type `%s'", ptr);
93 }
94
95 free(buffer);
96 return typemask;
97 }
98
dccp_parse(struct xt_option_call * cb)99 static void dccp_parse(struct xt_option_call *cb)
100 {
101 struct xt_dccp_info *einfo = cb->data;
102
103 xtables_option_parse(cb);
104 switch (cb->entry->id) {
105 case O_SOURCE_PORT:
106 einfo->flags |= XT_DCCP_SRC_PORTS;
107 if (cb->invert)
108 einfo->invflags |= XT_DCCP_SRC_PORTS;
109 break;
110 case O_DEST_PORT:
111 einfo->flags |= XT_DCCP_DEST_PORTS;
112 if (cb->invert)
113 einfo->invflags |= XT_DCCP_DEST_PORTS;
114 break;
115 case O_DCCP_TYPES:
116 einfo->flags |= XT_DCCP_TYPE;
117 einfo->typemask = parse_dccp_types(cb->arg);
118 if (cb->invert)
119 einfo->invflags |= XT_DCCP_TYPE;
120 break;
121 case O_DCCP_OPTION:
122 einfo->flags |= XT_DCCP_OPTION;
123 if (cb->invert)
124 einfo->invflags |= XT_DCCP_OPTION;
125 break;
126 }
127 }
128
129 static const char *
port_to_service(int port)130 port_to_service(int port)
131 {
132 const struct servent *service;
133
134 if ((service = getservbyport(htons(port), "dccp")))
135 return service->s_name;
136
137 return NULL;
138 }
139
140 static void
print_port(uint16_t port,int numeric)141 print_port(uint16_t port, int numeric)
142 {
143 const char *service;
144
145 if (numeric || (service = port_to_service(port)) == NULL)
146 printf("%u", port);
147 else
148 printf("%s", service);
149 }
150
151 static void
print_ports(const char * name,uint16_t min,uint16_t max,int invert,int numeric)152 print_ports(const char *name, uint16_t min, uint16_t max,
153 int invert, int numeric)
154 {
155 const char *inv = invert ? "!" : "";
156
157 if (min != 0 || max != 0xFFFF || invert) {
158 printf(" %s", name);
159 if (min == max) {
160 printf(":%s", inv);
161 print_port(min, numeric);
162 } else {
163 printf("s:%s", inv);
164 print_port(min, numeric);
165 printf(":");
166 print_port(max, numeric);
167 }
168 }
169 }
170
171 static void
print_types(uint16_t types,int inverted,int numeric)172 print_types(uint16_t types, int inverted, int numeric)
173 {
174 int have_type = 0;
175
176 if (inverted)
177 printf(" !");
178
179 printf(" ");
180 while (types) {
181 unsigned int i;
182
183 for (i = 0; !(types & (1 << i)); i++);
184
185 if (have_type)
186 printf(",");
187 else
188 have_type = 1;
189
190 if (numeric)
191 printf("%u", i);
192 else
193 printf("%s", dccp_pkt_types[i]);
194
195 types &= ~(1 << i);
196 }
197 }
198
199 static void
print_option(uint8_t option,int invert,int numeric)200 print_option(uint8_t option, int invert, int numeric)
201 {
202 if (option || invert)
203 printf(" option=%s%u", invert ? "!" : "", option);
204 }
205
206 static void
dccp_print(const void * ip,const struct xt_entry_match * match,int numeric)207 dccp_print(const void *ip, const struct xt_entry_match *match, int numeric)
208 {
209 const struct xt_dccp_info *einfo =
210 (const struct xt_dccp_info *)match->data;
211
212 printf(" dccp");
213
214 if (einfo->flags & XT_DCCP_SRC_PORTS) {
215 print_ports("spt", einfo->spts[0], einfo->spts[1],
216 einfo->invflags & XT_DCCP_SRC_PORTS,
217 numeric);
218 }
219
220 if (einfo->flags & XT_DCCP_DEST_PORTS) {
221 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
222 einfo->invflags & XT_DCCP_DEST_PORTS,
223 numeric);
224 }
225
226 if (einfo->flags & XT_DCCP_TYPE) {
227 print_types(einfo->typemask,
228 einfo->invflags & XT_DCCP_TYPE,
229 numeric);
230 }
231
232 if (einfo->flags & XT_DCCP_OPTION) {
233 print_option(einfo->option,
234 einfo->invflags & XT_DCCP_OPTION, numeric);
235 }
236 }
237
dccp_save(const void * ip,const struct xt_entry_match * match)238 static void dccp_save(const void *ip, const struct xt_entry_match *match)
239 {
240 const struct xt_dccp_info *einfo =
241 (const struct xt_dccp_info *)match->data;
242
243 if (einfo->flags & XT_DCCP_SRC_PORTS) {
244 if (einfo->invflags & XT_DCCP_SRC_PORTS)
245 printf(" !");
246 if (einfo->spts[0] != einfo->spts[1])
247 printf(" --sport %u:%u",
248 einfo->spts[0], einfo->spts[1]);
249 else
250 printf(" --sport %u", einfo->spts[0]);
251 }
252
253 if (einfo->flags & XT_DCCP_DEST_PORTS) {
254 if (einfo->invflags & XT_DCCP_DEST_PORTS)
255 printf(" !");
256 if (einfo->dpts[0] != einfo->dpts[1])
257 printf(" --dport %u:%u",
258 einfo->dpts[0], einfo->dpts[1]);
259 else
260 printf(" --dport %u", einfo->dpts[0]);
261 }
262
263 if (einfo->flags & XT_DCCP_TYPE) {
264 printf(" --dccp-type");
265 print_types(einfo->typemask, einfo->invflags & XT_DCCP_TYPE,0);
266 }
267
268 if (einfo->flags & XT_DCCP_OPTION) {
269 printf(" --dccp-option %s%u",
270 einfo->typemask & XT_DCCP_OPTION ? "! " : "",
271 einfo->option);
272 }
273 }
274
275 static struct xtables_match dccp_match = {
276 .name = "dccp",
277 .family = NFPROTO_UNSPEC,
278 .version = XTABLES_VERSION,
279 .size = XT_ALIGN(sizeof(struct xt_dccp_info)),
280 .userspacesize = XT_ALIGN(sizeof(struct xt_dccp_info)),
281 .help = dccp_help,
282 .print = dccp_print,
283 .save = dccp_save,
284 .x6_parse = dccp_parse,
285 .x6_options = dccp_opts,
286 };
287
_init(void)288 void _init(void)
289 {
290 xtables_register_match(&dccp_match);
291 }
292