libxt_dccp.c revision dd6e4b90b5b2dbc2bbaac5008e26949a18478197 
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
26enum {
27	O_SOURCE_PORT = 0,
28	O_DEST_PORT,
29	O_DCCP_TYPES,
30	O_DCCP_OPTION,
31};
32
33static 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
44static 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
61static 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
75static uint16_t
76parse_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
99static 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
129static const char *
130port_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
140static void
141print_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
151static void
152print_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
171static void
172print_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
199static void
200print_option(uint8_t option, int invert, int numeric)
201{
202	if (option || invert)
203		printf(" option=%s%u", invert ? "!" : "", option);
204}
205
206static void
207dccp_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
238static 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
275static 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
288void _init(void)
289{
290	xtables_register_match(&dccp_match);
291}
292