libxt_dccp.c revision 213e185afbb298e6708881e4c2adffdc47a8b6da 
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 <stdio.h>
9#include <string.h>
10#include <stdlib.h>
11#include <getopt.h>
12#include <netdb.h>
13#include <ctype.h>
14
15#include <netinet/in.h>
16#include <xtables.h>
17#include <linux/dccp.h>
18#include <linux/netfilter/x_tables.h>
19#include <linux/netfilter/xt_dccp.h>
20
21#if 0
22#define DEBUGP(format, first...) printf(format, ##first)
23#define static
24#else
25#define DEBUGP(format, fist...)
26#endif
27
28static void dccp_init(struct xt_entry_match *m)
29{
30	struct xt_dccp_info *einfo = (struct xt_dccp_info *)m->data;
31
32	memset(einfo, 0, sizeof(struct xt_dccp_info));
33}
34
35static void dccp_help(void)
36{
37	printf(
38"dccp match options\n"
39"[!] --source-port port[:port]                          match source port(s)\n"
40" --sport ...\n"
41"[!] --destination-port port[:port]                     match destination port(s)\n"
42" --dport ...\n");
43}
44
45static const struct option dccp_opts[] = {
46	{ .name = "source-port", .has_arg = 1, .val = '1' },
47	{ .name = "sport", .has_arg = 1, .val = '1' },
48	{ .name = "destination-port", .has_arg = 1, .val = '2' },
49	{ .name = "dport", .has_arg = 1, .val = '2' },
50	{ .name = "dccp-types", .has_arg = 1, .val = '3' },
51	{ .name = "dccp-option", .has_arg = 1, .val = '4' },
52	{ .name = NULL }
53};
54
55static void
56parse_dccp_ports(const char *portstring,
57		 u_int16_t *ports)
58{
59	char *buffer;
60	char *cp;
61
62	buffer = strdup(portstring);
63	DEBUGP("%s\n", portstring);
64	if ((cp = strchr(buffer, ':')) == NULL) {
65		ports[0] = ports[1] = parse_port(buffer, "dccp");
66	}
67	else {
68		*cp = '\0';
69		cp++;
70
71		ports[0] = buffer[0] ? parse_port(buffer, "dccp") : 0;
72		ports[1] = cp[0] ? parse_port(cp, "dccp") : 0xFFFF;
73
74		if (ports[0] > ports[1])
75			exit_error(PARAMETER_PROBLEM,
76				   "invalid portrange (min > max)");
77	}
78	free(buffer);
79}
80
81static const char *const dccp_pkt_types[] = {
82	[DCCP_PKT_REQUEST] 	= "REQUEST",
83	[DCCP_PKT_RESPONSE]	= "RESPONSE",
84	[DCCP_PKT_DATA]		= "DATA",
85	[DCCP_PKT_ACK]		= "ACK",
86	[DCCP_PKT_DATAACK]	= "DATAACK",
87	[DCCP_PKT_CLOSEREQ]	= "CLOSEREQ",
88	[DCCP_PKT_CLOSE]	= "CLOSE",
89	[DCCP_PKT_RESET]	= "RESET",
90	[DCCP_PKT_SYNC]		= "SYNC",
91	[DCCP_PKT_SYNCACK]	= "SYNCACK",
92	[DCCP_PKT_INVALID]	= "INVALID",
93};
94
95static u_int16_t
96parse_dccp_types(const char *typestring)
97{
98	u_int16_t typemask = 0;
99	char *ptr, *buffer;
100
101	buffer = strdup(typestring);
102
103	for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
104		unsigned int i;
105		for (i = 0; i < sizeof(dccp_pkt_types)/sizeof(char *); i++) {
106			if (!strcasecmp(dccp_pkt_types[i], ptr)) {
107				typemask |= (1 << i);
108				break;
109			}
110		}
111		if (i == sizeof(dccp_pkt_types)/sizeof(char *))
112			exit_error(PARAMETER_PROBLEM,
113				   "Unknown DCCP type `%s'", ptr);
114	}
115
116	free(buffer);
117	return typemask;
118}
119
120static u_int8_t parse_dccp_option(char *optstring)
121{
122	unsigned int ret;
123
124	if (string_to_number(optstring, 1, 255, &ret) == -1)
125		exit_error(PARAMETER_PROBLEM, "Bad DCCP option `%s'",
126			   optstring);
127
128	return ret;
129}
130
131static int
132dccp_parse(int c, char **argv, int invert, unsigned int *flags,
133           const void *entry, struct xt_entry_match **match)
134{
135	struct xt_dccp_info *einfo
136		= (struct xt_dccp_info *)(*match)->data;
137
138	switch (c) {
139	case '1':
140		if (*flags & XT_DCCP_SRC_PORTS)
141			exit_error(PARAMETER_PROBLEM,
142			           "Only one `--source-port' allowed");
143		einfo->flags |= XT_DCCP_SRC_PORTS;
144		check_inverse(optarg, &invert, &optind, 0);
145		parse_dccp_ports(argv[optind-1], einfo->spts);
146		if (invert)
147			einfo->invflags |= XT_DCCP_SRC_PORTS;
148		*flags |= XT_DCCP_SRC_PORTS;
149		break;
150
151	case '2':
152		if (*flags & XT_DCCP_DEST_PORTS)
153			exit_error(PARAMETER_PROBLEM,
154				   "Only one `--destination-port' allowed");
155		einfo->flags |= XT_DCCP_DEST_PORTS;
156		check_inverse(optarg, &invert, &optind, 0);
157		parse_dccp_ports(argv[optind-1], einfo->dpts);
158		if (invert)
159			einfo->invflags |= XT_DCCP_DEST_PORTS;
160		*flags |= XT_DCCP_DEST_PORTS;
161		break;
162
163	case '3':
164		if (*flags & XT_DCCP_TYPE)
165			exit_error(PARAMETER_PROBLEM,
166				   "Only one `--dccp-types' allowed");
167		einfo->flags |= XT_DCCP_TYPE;
168		check_inverse(optarg, &invert, &optind, 0);
169		einfo->typemask = parse_dccp_types(argv[optind-1]);
170		if (invert)
171			einfo->invflags |= XT_DCCP_TYPE;
172		*flags |= XT_DCCP_TYPE;
173		break;
174
175	case '4':
176		if (*flags & XT_DCCP_OPTION)
177			exit_error(PARAMETER_PROBLEM,
178				   "Only one `--dccp-option' allowed");
179		einfo->flags |= XT_DCCP_OPTION;
180		check_inverse(optarg, &invert, &optind, 0);
181		einfo->option = parse_dccp_option(argv[optind-1]);
182		if (invert)
183			einfo->invflags |= XT_DCCP_OPTION;
184		*flags |= XT_DCCP_OPTION;
185		break;
186	default:
187		return 0;
188	}
189	return 1;
190}
191
192static char *
193port_to_service(int port)
194{
195	struct servent *service;
196
197	if ((service = getservbyport(htons(port), "dccp")))
198		return service->s_name;
199
200	return NULL;
201}
202
203static void
204print_port(u_int16_t port, int numeric)
205{
206	char *service;
207
208	if (numeric || (service = port_to_service(port)) == NULL)
209		printf("%u", port);
210	else
211		printf("%s", service);
212}
213
214static void
215print_ports(const char *name, u_int16_t min, u_int16_t max,
216	    int invert, int numeric)
217{
218	const char *inv = invert ? "!" : "";
219
220	if (min != 0 || max != 0xFFFF || invert) {
221		printf("%s", name);
222		if (min == max) {
223			printf(":%s", inv);
224			print_port(min, numeric);
225		} else {
226			printf("s:%s", inv);
227			print_port(min, numeric);
228			printf(":");
229			print_port(max, numeric);
230		}
231		printf(" ");
232	}
233}
234
235static void
236print_types(u_int16_t types, int inverted, int numeric)
237{
238	int have_type = 0;
239
240	if (inverted)
241		printf("! ");
242
243	while (types) {
244		unsigned int i;
245
246		for (i = 0; !(types & (1 << i)); i++);
247
248		if (have_type)
249			printf(",");
250		else
251			have_type = 1;
252
253		if (numeric)
254			printf("%u", i);
255		else
256			printf("%s", dccp_pkt_types[i]);
257
258		types &= ~(1 << i);
259	}
260}
261
262static void
263print_option(u_int8_t option, int invert, int numeric)
264{
265	if (option || invert)
266		printf("option=%s%u ", invert ? "!" : "", option);
267}
268
269static void
270dccp_print(const void *ip, const struct xt_entry_match *match, int numeric)
271{
272	const struct xt_dccp_info *einfo =
273		(const struct xt_dccp_info *)match->data;
274
275	printf("dccp ");
276
277	if (einfo->flags & XT_DCCP_SRC_PORTS) {
278		print_ports("spt", einfo->spts[0], einfo->spts[1],
279			einfo->invflags & XT_DCCP_SRC_PORTS,
280			numeric);
281	}
282
283	if (einfo->flags & XT_DCCP_DEST_PORTS) {
284		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
285			einfo->invflags & XT_DCCP_DEST_PORTS,
286			numeric);
287	}
288
289	if (einfo->flags & XT_DCCP_TYPE) {
290		print_types(einfo->typemask,
291			   einfo->invflags & XT_DCCP_TYPE,
292			   numeric);
293	}
294
295	if (einfo->flags & XT_DCCP_OPTION) {
296		print_option(einfo->option,
297			     einfo->invflags & XT_DCCP_OPTION, numeric);
298	}
299}
300
301static void dccp_save(const void *ip, const struct xt_entry_match *match)
302{
303	const struct xt_dccp_info *einfo =
304		(const struct xt_dccp_info *)match->data;
305
306	if (einfo->flags & XT_DCCP_SRC_PORTS) {
307		if (einfo->invflags & XT_DCCP_SRC_PORTS)
308			printf("! ");
309		if (einfo->spts[0] != einfo->spts[1])
310			printf("--sport %u:%u ",
311			       einfo->spts[0], einfo->spts[1]);
312		else
313			printf("--sport %u ", einfo->spts[0]);
314	}
315
316	if (einfo->flags & XT_DCCP_DEST_PORTS) {
317		if (einfo->invflags & XT_DCCP_DEST_PORTS)
318			printf("! ");
319		if (einfo->dpts[0] != einfo->dpts[1])
320			printf("--dport %u:%u ",
321			       einfo->dpts[0], einfo->dpts[1]);
322		else
323			printf("--dport %u ", einfo->dpts[0]);
324	}
325
326	if (einfo->flags & XT_DCCP_TYPE) {
327		printf("--dccp-type ");
328		print_types(einfo->typemask, einfo->invflags & XT_DCCP_TYPE,0);
329	}
330
331	if (einfo->flags & XT_DCCP_OPTION) {
332		printf("--dccp-option %s%u ",
333			einfo->typemask & XT_DCCP_OPTION ? "! " : "",
334			einfo->option);
335	}
336}
337
338static struct xtables_match dccp_match = {
339	.name		= "dccp",
340	.family		= NFPROTO_IPV4,
341	.version	= XTABLES_VERSION,
342	.size		= XT_ALIGN(sizeof(struct xt_dccp_info)),
343	.userspacesize	= XT_ALIGN(sizeof(struct xt_dccp_info)),
344	.help		= dccp_help,
345	.init		= dccp_init,
346	.parse		= dccp_parse,
347	.print		= dccp_print,
348	.save		= dccp_save,
349	.extra_opts	= dccp_opts,
350};
351
352static struct xtables_match dccp_match6 = {
353	.name		= "dccp",
354	.family		= NFPROTO_IPV6,
355	.version	= XTABLES_VERSION,
356	.size		= XT_ALIGN(sizeof(struct xt_dccp_info)),
357	.userspacesize	= XT_ALIGN(sizeof(struct xt_dccp_info)),
358	.help		= dccp_help,
359	.init		= dccp_init,
360	.parse		= dccp_parse,
361	.print		= dccp_print,
362	.save		= dccp_save,
363	.extra_opts	= dccp_opts,
364};
365
366void _init(void)
367{
368	xtables_register_match(&dccp_match);
369	xtables_register_match(&dccp_match6);
370}
371