libxt_sctp.c revision e88a7c2c7175742b58b6aa03f2b5aba2d80330a1 
1/* Shared library add-on to iptables for SCTP matching
2 *
3 * (C) 2003 by Harald Welte <laforge@gnumonks.org>
4 *
5 * This program is distributed under the terms of GNU GPL v2, 1991
6 *
7 * libipt_ecn.c borrowed heavily from libipt_dscp.c
8 *
9 */
10#include <stdbool.h>
11#include <stdio.h>
12#include <string.h>
13#include <stdlib.h>
14#include <getopt.h>
15#include <netdb.h>
16#include <ctype.h>
17
18#include <netinet/in.h>
19#include <xtables.h>
20
21#include <linux/netfilter/xt_sctp.h>
22
23#if 0
24#define DEBUGP(format, first...) printf(format, ##first)
25#define static
26#else
27#define DEBUGP(format, fist...)
28#endif
29
30static void
31print_chunk(uint32_t chunknum, int numeric);
32
33static void sctp_init(struct xt_entry_match *m)
34{
35	int i;
36	struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
37
38	for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
39		einfo->flag_info[i].chunktype = -1;
40	}
41}
42
43static void sctp_help(void)
44{
45	printf(
46"sctp match options\n"
47"[!] --source-port port[:port]                          match source port(s)\n"
48" --sport ...\n"
49"[!] --destination-port port[:port]                     match destination port(s)\n"
50" --dport ...\n"
51"[!] --chunk-types (all|any|none) (chunktype[:flags])+	match if all, any or none of\n"
52"						        chunktypes are present\n"
53"chunktypes - DATA INIT INIT_ACK SACK HEARTBEAT HEARTBEAT_ACK ABORT SHUTDOWN SHUTDOWN_ACK ERROR COOKIE_ECHO COOKIE_ACK ECN_ECNE ECN_CWR SHUTDOWN_COMPLETE ASCONF ASCONF_ACK FORWARD_TSN ALL NONE\n");
54}
55
56static const struct option sctp_opts[] = {
57	{.name = "source-port",      .has_arg = true, .val = '1'},
58	{.name = "sport",            .has_arg = true, .val = '1'},
59	{.name = "destination-port", .has_arg = true, .val = '2'},
60	{.name = "dport",            .has_arg = true, .val = '2'},
61	{.name = "chunk-types",      .has_arg = true, .val = '3'},
62	XT_GETOPT_TABLEEND,
63};
64
65static void
66parse_sctp_ports(const char *portstring,
67		 uint16_t *ports)
68{
69	char *buffer;
70	char *cp;
71
72	buffer = strdup(portstring);
73	DEBUGP("%s\n", portstring);
74	if ((cp = strchr(buffer, ':')) == NULL) {
75		ports[0] = ports[1] = xtables_parse_port(buffer, "sctp");
76	}
77	else {
78		*cp = '\0';
79		cp++;
80
81		ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0;
82		ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF;
83
84		if (ports[0] > ports[1])
85			xtables_error(PARAMETER_PROBLEM,
86				   "invalid portrange (min > max)");
87	}
88	free(buffer);
89}
90
91struct sctp_chunk_names {
92	const char *name;
93	unsigned int chunk_type;
94	const char *valid_flags;
95};
96
97/*'ALL' and 'NONE' will be treated specially. */
98static const struct sctp_chunk_names sctp_chunk_names[]
99= { { .name = "DATA", 		.chunk_type = 0,   .valid_flags = "----IUBE"},
100    { .name = "INIT", 		.chunk_type = 1,   .valid_flags = "--------"},
101    { .name = "INIT_ACK", 	.chunk_type = 2,   .valid_flags = "--------"},
102    { .name = "SACK",		.chunk_type = 3,   .valid_flags = "--------"},
103    { .name = "HEARTBEAT",	.chunk_type = 4,   .valid_flags = "--------"},
104    { .name = "HEARTBEAT_ACK",	.chunk_type = 5,   .valid_flags = "--------"},
105    { .name = "ABORT",		.chunk_type = 6,   .valid_flags = "-------T"},
106    { .name = "SHUTDOWN",	.chunk_type = 7,   .valid_flags = "--------"},
107    { .name = "SHUTDOWN_ACK",	.chunk_type = 8,   .valid_flags = "--------"},
108    { .name = "ERROR",		.chunk_type = 9,   .valid_flags = "--------"},
109    { .name = "COOKIE_ECHO",	.chunk_type = 10,  .valid_flags = "--------"},
110    { .name = "COOKIE_ACK",	.chunk_type = 11,  .valid_flags = "--------"},
111    { .name = "ECN_ECNE",	.chunk_type = 12,  .valid_flags = "--------"},
112    { .name = "ECN_CWR",	.chunk_type = 13,  .valid_flags = "--------"},
113    { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
114    { .name = "ASCONF",		.chunk_type = 193,  .valid_flags = "--------"},
115    { .name = "ASCONF_ACK",	.chunk_type = 128,  .valid_flags = "--------"},
116    { .name = "FORWARD_TSN",	.chunk_type = 192,  .valid_flags = "--------"},
117};
118
119static void
120save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
121		     int *flag_count,
122		     int chunktype,
123		     int bit,
124		     int set)
125{
126	int i;
127
128	for (i = 0; i < *flag_count; i++) {
129		if (flag_info[i].chunktype == chunktype) {
130			DEBUGP("Previous match found\n");
131			flag_info[i].chunktype = chunktype;
132			flag_info[i].flag_mask |= (1 << bit);
133			if (set) {
134				flag_info[i].flag |= (1 << bit);
135			}
136
137			return;
138		}
139	}
140
141	if (*flag_count == XT_NUM_SCTP_FLAGS) {
142		xtables_error (PARAMETER_PROBLEM,
143			"Number of chunk types with flags exceeds currently allowed limit."
144			"Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
145			"recompiling both the kernel space and user space modules\n");
146	}
147
148	flag_info[*flag_count].chunktype = chunktype;
149	flag_info[*flag_count].flag_mask |= (1 << bit);
150	if (set) {
151		flag_info[*flag_count].flag |= (1 << bit);
152	}
153	(*flag_count)++;
154}
155
156static void
157parse_sctp_chunk(struct xt_sctp_info *einfo,
158		 const char *chunks)
159{
160	char *ptr;
161	char *buffer;
162	unsigned int i, j;
163	int found = 0;
164	char *chunk_flags;
165
166	buffer = strdup(chunks);
167	DEBUGP("Buffer: %s\n", buffer);
168
169	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
170
171	if (!strcasecmp(buffer, "ALL")) {
172		SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
173		goto out;
174	}
175
176	if (!strcasecmp(buffer, "NONE")) {
177		SCTP_CHUNKMAP_RESET(einfo->chunkmap);
178		goto out;
179	}
180
181	for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
182		found = 0;
183		DEBUGP("Next Chunk type %s\n", ptr);
184
185		if ((chunk_flags = strchr(ptr, ':')) != NULL) {
186			*chunk_flags++ = 0;
187		}
188
189		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
190			if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
191				DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
192				SCTP_CHUNKMAP_SET(einfo->chunkmap,
193					sctp_chunk_names[i].chunk_type);
194				found = 1;
195				break;
196			}
197		if (!found)
198			xtables_error(PARAMETER_PROBLEM,
199				   "Unknown sctp chunk `%s'", ptr);
200
201		if (chunk_flags) {
202			DEBUGP("Chunk flags %s\n", chunk_flags);
203			for (j = 0; j < strlen(chunk_flags); j++) {
204				char *p;
205				int bit;
206
207				if ((p = strchr(sctp_chunk_names[i].valid_flags,
208						toupper(chunk_flags[j]))) != NULL) {
209					bit = p - sctp_chunk_names[i].valid_flags;
210					bit = 7 - bit;
211
212					save_chunk_flag_info(einfo->flag_info,
213						&(einfo->flag_count), i, bit,
214						isupper(chunk_flags[j]));
215				} else {
216					xtables_error(PARAMETER_PROBLEM,
217						"Invalid flags for chunk type %d\n", i);
218				}
219			}
220		}
221	}
222out:
223	free(buffer);
224}
225
226static void
227parse_sctp_chunks(struct xt_sctp_info *einfo,
228		  const char *match_type,
229		  const char *chunks)
230{
231	DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
232	if (!strcasecmp(match_type, "ANY")) {
233		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
234	} else 	if (!strcasecmp(match_type, "ALL")) {
235		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
236	} else 	if (!strcasecmp(match_type, "ONLY")) {
237		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
238	} else {
239		xtables_error (PARAMETER_PROBLEM,
240			"Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
241	}
242
243	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
244	parse_sctp_chunk(einfo, chunks);
245}
246
247static int
248sctp_parse(int c, char **argv, int invert, unsigned int *flags,
249           const void *entry, struct xt_entry_match **match)
250{
251	struct xt_sctp_info *einfo
252		= (struct xt_sctp_info *)(*match)->data;
253
254	switch (c) {
255	case '1':
256		if (*flags & XT_SCTP_SRC_PORTS)
257			xtables_error(PARAMETER_PROBLEM,
258			           "Only one `--source-port' allowed");
259		einfo->flags |= XT_SCTP_SRC_PORTS;
260		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
261		parse_sctp_ports(optarg, einfo->spts);
262		if (invert)
263			einfo->invflags |= XT_SCTP_SRC_PORTS;
264		*flags |= XT_SCTP_SRC_PORTS;
265		break;
266
267	case '2':
268		if (*flags & XT_SCTP_DEST_PORTS)
269			xtables_error(PARAMETER_PROBLEM,
270				   "Only one `--destination-port' allowed");
271		einfo->flags |= XT_SCTP_DEST_PORTS;
272		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
273		parse_sctp_ports(optarg, einfo->dpts);
274		if (invert)
275			einfo->invflags |= XT_SCTP_DEST_PORTS;
276		*flags |= XT_SCTP_DEST_PORTS;
277		break;
278
279	case '3':
280		if (*flags & XT_SCTP_CHUNK_TYPES)
281			xtables_error(PARAMETER_PROBLEM,
282				   "Only one `--chunk-types' allowed");
283		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
284
285		if (!argv[optind]
286		    || argv[optind][0] == '-' || argv[optind][0] == '!')
287			xtables_error(PARAMETER_PROBLEM,
288				   "--chunk-types requires two args");
289
290		einfo->flags |= XT_SCTP_CHUNK_TYPES;
291		parse_sctp_chunks(einfo, optarg, argv[optind]);
292		if (invert)
293			einfo->invflags |= XT_SCTP_CHUNK_TYPES;
294		optind++;
295		*flags |= XT_SCTP_CHUNK_TYPES;
296		break;
297	}
298	return 1;
299}
300
301static char *
302port_to_service(int port)
303{
304	struct servent *service;
305
306	if ((service = getservbyport(htons(port), "sctp")))
307		return service->s_name;
308
309	return NULL;
310}
311
312static void
313print_port(uint16_t port, int numeric)
314{
315	char *service;
316
317	if (numeric || (service = port_to_service(port)) == NULL)
318		printf("%u", port);
319	else
320		printf("%s", service);
321}
322
323static void
324print_ports(const char *name, uint16_t min, uint16_t max,
325	    int invert, int numeric)
326{
327	const char *inv = invert ? "!" : "";
328
329	if (min != 0 || max != 0xFFFF || invert) {
330		printf(" %s", name);
331		if (min == max) {
332			printf(":%s", inv);
333			print_port(min, numeric);
334		} else {
335			printf("s:%s", inv);
336			print_port(min, numeric);
337			printf(":");
338			print_port(max, numeric);
339		}
340	}
341}
342
343static void
344print_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask)
345{
346	int i;
347
348	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
349			chunk_flags_mask);
350
351	if (chunk_flags_mask) {
352		printf(":");
353	}
354
355	for (i = 7; i >= 0; i--) {
356		if (chunk_flags_mask & (1 << i)) {
357			if (chunk_flags & (1 << i)) {
358				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
359			} else {
360				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
361			}
362		}
363	}
364}
365
366static void
367print_chunk(uint32_t chunknum, int numeric)
368{
369	if (numeric) {
370		printf("0x%04X", chunknum);
371	}
372	else {
373		int i;
374
375		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
376			if (sctp_chunk_names[i].chunk_type == chunknum)
377				printf("%s", sctp_chunk_names[chunknum].name);
378	}
379}
380
381static void
382print_chunks(const struct xt_sctp_info *einfo, int numeric)
383{
384	uint32_t chunk_match_type = einfo->chunk_match_type;
385	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
386	int flag_count = einfo->flag_count;
387	int i, j;
388	int flag;
389
390	switch (chunk_match_type) {
391		case SCTP_CHUNK_MATCH_ANY:	printf(" any"); break;
392		case SCTP_CHUNK_MATCH_ALL:	printf(" all"); break;
393		case SCTP_CHUNK_MATCH_ONLY:	printf(" only"); break;
394		default:	printf("Never reach here\n"); break;
395	}
396
397	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
398		printf(" NONE");
399		goto out;
400	}
401
402	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
403		printf(" ALL");
404		goto out;
405	}
406
407	flag = 0;
408	for (i = 0; i < 256; i++) {
409		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
410			if (flag)
411				printf(",");
412			else
413				putchar(' ');
414			flag = 1;
415			print_chunk(i, numeric);
416			for (j = 0; j < flag_count; j++) {
417				if (flag_info[j].chunktype == i) {
418					print_chunk_flags(i, flag_info[j].flag,
419						flag_info[j].flag_mask);
420				}
421			}
422		}
423	}
424out:
425	return;
426}
427
428static void
429sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
430{
431	const struct xt_sctp_info *einfo =
432		(const struct xt_sctp_info *)match->data;
433
434	printf(" sctp");
435
436	if (einfo->flags & XT_SCTP_SRC_PORTS) {
437		print_ports("spt", einfo->spts[0], einfo->spts[1],
438			einfo->invflags & XT_SCTP_SRC_PORTS,
439			numeric);
440	}
441
442	if (einfo->flags & XT_SCTP_DEST_PORTS) {
443		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
444			einfo->invflags & XT_SCTP_DEST_PORTS,
445			numeric);
446	}
447
448	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
449		/* FIXME: print_chunks() is used in save() where the printing of '!'
450		s taken care of, so we need to do that here as well */
451		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
452			printf(" !");
453		}
454		print_chunks(einfo, numeric);
455	}
456}
457
458static void sctp_save(const void *ip, const struct xt_entry_match *match)
459{
460	const struct xt_sctp_info *einfo =
461		(const struct xt_sctp_info *)match->data;
462
463	if (einfo->flags & XT_SCTP_SRC_PORTS) {
464		if (einfo->invflags & XT_SCTP_SRC_PORTS)
465			printf(" !");
466		if (einfo->spts[0] != einfo->spts[1])
467			printf(" --sport %u:%u",
468			       einfo->spts[0], einfo->spts[1]);
469		else
470			printf(" --sport %u", einfo->spts[0]);
471	}
472
473	if (einfo->flags & XT_SCTP_DEST_PORTS) {
474		if (einfo->invflags & XT_SCTP_DEST_PORTS)
475			printf(" !");
476		if (einfo->dpts[0] != einfo->dpts[1])
477			printf(" --dport %u:%u",
478			       einfo->dpts[0], einfo->dpts[1]);
479		else
480			printf(" --dport %u", einfo->dpts[0]);
481	}
482
483	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
484		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
485			printf(" !");
486		printf(" --chunk-types");
487
488		print_chunks(einfo, 0);
489	}
490}
491
492static struct xtables_match sctp_match = {
493	.name		= "sctp",
494	.family		= NFPROTO_UNSPEC,
495	.version	= XTABLES_VERSION,
496	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
497	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
498	.help		= sctp_help,
499	.init		= sctp_init,
500	.parse		= sctp_parse,
501	.print		= sctp_print,
502	.save		= sctp_save,
503	.extra_opts	= sctp_opts,
504};
505
506void _init(void)
507{
508	xtables_register_match(&sctp_match);
509}
510