libxt_sctp.c revision 03d99486d8283552705b58dc55b6085dffc38792 
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 <stdio.h>
11#include <string.h>
12#include <stdlib.h>
13#include <getopt.h>
14#include <netdb.h>
15#include <ctype.h>
16
17#include <netinet/in.h>
18#include <xtables.h>
19
20#ifndef ARRAY_SIZE
21#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
22#endif
23
24#include <linux/netfilter/xt_sctp.h>
25
26/* Some ZS!#@:$%*#$! has replaced the ELEMCOUNT macro in ipt_sctp.h with
27 * ARRAY_SIZE without noticing that this file is used from userspace,
28 * and userspace doesn't have ARRAY_SIZE */
29
30#ifndef ELEMCOUNT
31#define ELEMCOUNT ARRAY_SIZE
32#endif
33
34#if 0
35#define DEBUGP(format, first...) printf(format, ##first)
36#define static
37#else
38#define DEBUGP(format, fist...)
39#endif
40
41static void
42print_chunk(u_int32_t chunknum, int numeric);
43
44static void sctp_init(struct xt_entry_match *m)
45{
46	int i;
47	struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
48
49	memset(einfo, 0, sizeof(struct xt_sctp_info));
50
51	for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
52		einfo->flag_info[i].chunktype = -1;
53	}
54}
55
56static void sctp_help(void)
57{
58	printf(
59"sctp match options\n"
60"[!] --source-port port[:port]                          match source port(s)\n"
61" --sport ...\n"
62"[!] --destination-port port[:port]                     match destination port(s)\n"
63" --dport ...\n"
64"[!] --chunk-types (all|any|none) (chunktype[:flags])+	match if all, any or none of\n"
65"						        chunktypes are present\n"
66"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 ALL NONE\n");
67}
68
69static const struct option sctp_opts[] = {
70	{ .name = "source-port", .has_arg = 1, .val = '1' },
71	{ .name = "sport", .has_arg = 1, .val = '1' },
72	{ .name = "destination-port", .has_arg = 1, .val = '2' },
73	{ .name = "dport", .has_arg = 1, .val = '2' },
74	{ .name = "chunk-types", .has_arg = 1, .val = '3' },
75	{ .name = NULL }
76};
77
78static void
79parse_sctp_ports(const char *portstring,
80		 u_int16_t *ports)
81{
82	char *buffer;
83	char *cp;
84
85	buffer = strdup(portstring);
86	DEBUGP("%s\n", portstring);
87	if ((cp = strchr(buffer, ':')) == NULL) {
88		ports[0] = ports[1] = parse_port(buffer, "sctp");
89	}
90	else {
91		*cp = '\0';
92		cp++;
93
94		ports[0] = buffer[0] ? parse_port(buffer, "sctp") : 0;
95		ports[1] = cp[0] ? parse_port(cp, "sctp") : 0xFFFF;
96
97		if (ports[0] > ports[1])
98			exit_error(PARAMETER_PROBLEM,
99				   "invalid portrange (min > max)");
100	}
101	free(buffer);
102}
103
104struct sctp_chunk_names {
105	const char *name;
106	unsigned int chunk_type;
107	const char *valid_flags;
108};
109
110/*'ALL' and 'NONE' will be treated specially. */
111static const struct sctp_chunk_names sctp_chunk_names[]
112= { { .name = "DATA", 		.chunk_type = 0,   .valid_flags = "-----UBE"},
113    { .name = "INIT", 		.chunk_type = 1,   .valid_flags = "--------"},
114    { .name = "INIT_ACK", 	.chunk_type = 2,   .valid_flags = "--------"},
115    { .name = "SACK",		.chunk_type = 3,   .valid_flags = "--------"},
116    { .name = "HEARTBEAT",	.chunk_type = 4,   .valid_flags = "--------"},
117    { .name = "HEARTBEAT_ACK",	.chunk_type = 5,   .valid_flags = "--------"},
118    { .name = "ABORT",		.chunk_type = 6,   .valid_flags = "-------T"},
119    { .name = "SHUTDOWN",	.chunk_type = 7,   .valid_flags = "--------"},
120    { .name = "SHUTDOWN_ACK",	.chunk_type = 8,   .valid_flags = "--------"},
121    { .name = "ERROR",		.chunk_type = 9,   .valid_flags = "--------"},
122    { .name = "COOKIE_ECHO",	.chunk_type = 10,  .valid_flags = "--------"},
123    { .name = "COOKIE_ACK",	.chunk_type = 11,  .valid_flags = "--------"},
124    { .name = "ECN_ECNE",	.chunk_type = 12,  .valid_flags = "--------"},
125    { .name = "ECN_CWR",	.chunk_type = 13,  .valid_flags = "--------"},
126    { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
127    { .name = "ASCONF",		.chunk_type = 193,  .valid_flags = "--------"},
128    { .name = "ASCONF_ACK",	.chunk_type = 128,  .valid_flags = "--------"},
129};
130
131static void
132save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
133		     int *flag_count,
134		     int chunktype,
135		     int bit,
136		     int set)
137{
138	int i;
139
140	for (i = 0; i < *flag_count; i++) {
141		if (flag_info[i].chunktype == chunktype) {
142			DEBUGP("Previous match found\n");
143			flag_info[i].chunktype = chunktype;
144			flag_info[i].flag_mask |= (1 << bit);
145			if (set) {
146				flag_info[i].flag |= (1 << bit);
147			}
148
149			return;
150		}
151	}
152
153	if (*flag_count == XT_NUM_SCTP_FLAGS) {
154		exit_error (PARAMETER_PROBLEM,
155			"Number of chunk types with flags exceeds currently allowed limit."
156			"Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
157			"recompiling both the kernel space and user space modules\n");
158	}
159
160	flag_info[*flag_count].chunktype = chunktype;
161	flag_info[*flag_count].flag_mask |= (1 << bit);
162	if (set) {
163		flag_info[*flag_count].flag |= (1 << bit);
164	}
165	(*flag_count)++;
166}
167
168static void
169parse_sctp_chunk(struct xt_sctp_info *einfo,
170		 const char *chunks)
171{
172	char *ptr;
173	char *buffer;
174	unsigned int i, j;
175	int found = 0;
176	char *chunk_flags;
177
178	buffer = strdup(chunks);
179	DEBUGP("Buffer: %s\n", buffer);
180
181	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
182
183	if (!strcasecmp(buffer, "ALL")) {
184		SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
185		goto out;
186	}
187
188	if (!strcasecmp(buffer, "NONE")) {
189		SCTP_CHUNKMAP_RESET(einfo->chunkmap);
190		goto out;
191	}
192
193	for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
194		found = 0;
195		DEBUGP("Next Chunk type %s\n", ptr);
196
197		if ((chunk_flags = strchr(ptr, ':')) != NULL) {
198			*chunk_flags++ = 0;
199		}
200
201		for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
202			if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
203				DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
204				SCTP_CHUNKMAP_SET(einfo->chunkmap,
205					sctp_chunk_names[i].chunk_type);
206				found = 1;
207				break;
208			}
209		}
210		if (!found)
211			exit_error(PARAMETER_PROBLEM,
212				   "Unknown sctp chunk `%s'", ptr);
213
214		if (chunk_flags) {
215			DEBUGP("Chunk flags %s\n", chunk_flags);
216			for (j = 0; j < strlen(chunk_flags); j++) {
217				char *p;
218				int bit;
219
220				if ((p = strchr(sctp_chunk_names[i].valid_flags,
221						toupper(chunk_flags[j]))) != NULL) {
222					bit = p - sctp_chunk_names[i].valid_flags;
223					bit = 7 - bit;
224
225					save_chunk_flag_info(einfo->flag_info,
226						&(einfo->flag_count), i, bit,
227						isupper(chunk_flags[j]));
228				} else {
229					exit_error(PARAMETER_PROBLEM,
230						"Invalid flags for chunk type %d\n", i);
231				}
232			}
233		}
234	}
235out:
236	free(buffer);
237}
238
239static void
240parse_sctp_chunks(struct xt_sctp_info *einfo,
241		  const char *match_type,
242		  const char *chunks)
243{
244	DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
245	if (!strcasecmp(match_type, "ANY")) {
246		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
247	} else 	if (!strcasecmp(match_type, "ALL")) {
248		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
249	} else 	if (!strcasecmp(match_type, "ONLY")) {
250		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
251	} else {
252		exit_error (PARAMETER_PROBLEM,
253			"Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
254	}
255
256	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
257	parse_sctp_chunk(einfo, chunks);
258}
259
260static int
261sctp_parse(int c, char **argv, int invert, unsigned int *flags,
262           const void *entry, struct xt_entry_match **match)
263{
264	struct xt_sctp_info *einfo
265		= (struct xt_sctp_info *)(*match)->data;
266
267	switch (c) {
268	case '1':
269		if (*flags & XT_SCTP_SRC_PORTS)
270			exit_error(PARAMETER_PROBLEM,
271			           "Only one `--source-port' allowed");
272		einfo->flags |= XT_SCTP_SRC_PORTS;
273		check_inverse(optarg, &invert, &optind, 0);
274		parse_sctp_ports(argv[optind-1], einfo->spts);
275		if (invert)
276			einfo->invflags |= XT_SCTP_SRC_PORTS;
277		*flags |= XT_SCTP_SRC_PORTS;
278		break;
279
280	case '2':
281		if (*flags & XT_SCTP_DEST_PORTS)
282			exit_error(PARAMETER_PROBLEM,
283				   "Only one `--destination-port' allowed");
284		einfo->flags |= XT_SCTP_DEST_PORTS;
285		check_inverse(optarg, &invert, &optind, 0);
286		parse_sctp_ports(argv[optind-1], einfo->dpts);
287		if (invert)
288			einfo->invflags |= XT_SCTP_DEST_PORTS;
289		*flags |= XT_SCTP_DEST_PORTS;
290		break;
291
292	case '3':
293		if (*flags & XT_SCTP_CHUNK_TYPES)
294			exit_error(PARAMETER_PROBLEM,
295				   "Only one `--chunk-types' allowed");
296		check_inverse(optarg, &invert, &optind, 0);
297
298		if (!argv[optind]
299		    || argv[optind][0] == '-' || argv[optind][0] == '!')
300			exit_error(PARAMETER_PROBLEM,
301				   "--chunk-types requires two args");
302
303		einfo->flags |= XT_SCTP_CHUNK_TYPES;
304		parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
305		if (invert)
306			einfo->invflags |= XT_SCTP_CHUNK_TYPES;
307		optind++;
308		*flags |= XT_SCTP_CHUNK_TYPES;
309		break;
310
311	default:
312		return 0;
313	}
314	return 1;
315}
316
317static char *
318port_to_service(int port)
319{
320	struct servent *service;
321
322	if ((service = getservbyport(htons(port), "sctp")))
323		return service->s_name;
324
325	return NULL;
326}
327
328static void
329print_port(u_int16_t port, int numeric)
330{
331	char *service;
332
333	if (numeric || (service = port_to_service(port)) == NULL)
334		printf("%u", port);
335	else
336		printf("%s", service);
337}
338
339static void
340print_ports(const char *name, u_int16_t min, u_int16_t max,
341	    int invert, int numeric)
342{
343	const char *inv = invert ? "!" : "";
344
345	if (min != 0 || max != 0xFFFF || invert) {
346		printf("%s", name);
347		if (min == max) {
348			printf(":%s", inv);
349			print_port(min, numeric);
350		} else {
351			printf("s:%s", inv);
352			print_port(min, numeric);
353			printf(":");
354			print_port(max, numeric);
355		}
356		printf(" ");
357	}
358}
359
360static void
361print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
362{
363	int i;
364
365	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
366			chunk_flags_mask);
367
368	if (chunk_flags_mask) {
369		printf(":");
370	}
371
372	for (i = 7; i >= 0; i--) {
373		if (chunk_flags_mask & (1 << i)) {
374			if (chunk_flags & (1 << i)) {
375				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
376			} else {
377				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
378			}
379		}
380	}
381}
382
383static void
384print_chunk(u_int32_t chunknum, int numeric)
385{
386	if (numeric) {
387		printf("0x%04X", chunknum);
388	}
389	else {
390		int i;
391
392		for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
393			if (sctp_chunk_names[i].chunk_type == chunknum)
394				printf("%s", sctp_chunk_names[chunknum].name);
395		}
396	}
397}
398
399static void
400print_chunks(const struct xt_sctp_info *einfo, int numeric)
401{
402	u_int32_t chunk_match_type = einfo->chunk_match_type;
403	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
404	int flag_count = einfo->flag_count;
405	int i, j;
406	int flag;
407
408	switch (chunk_match_type) {
409		case SCTP_CHUNK_MATCH_ANY:	printf("any "); break;
410		case SCTP_CHUNK_MATCH_ALL:	printf("all "); break;
411		case SCTP_CHUNK_MATCH_ONLY:	printf("only "); break;
412		default:	printf("Never reach herer\n"); break;
413	}
414
415	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
416		printf("NONE ");
417		goto out;
418	}
419
420	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
421		printf("ALL ");
422		goto out;
423	}
424
425	flag = 0;
426	for (i = 0; i < 256; i++) {
427		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
428			if (flag)
429				printf(",");
430			flag = 1;
431			print_chunk(i, numeric);
432			for (j = 0; j < flag_count; j++) {
433				if (flag_info[j].chunktype == i) {
434					print_chunk_flags(i, flag_info[j].flag,
435						flag_info[j].flag_mask);
436				}
437			}
438		}
439	}
440
441	if (flag)
442		printf(" ");
443out:
444	return;
445}
446
447static void
448sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
449{
450	const struct xt_sctp_info *einfo =
451		(const struct xt_sctp_info *)match->data;
452
453	printf("sctp ");
454
455	if (einfo->flags & XT_SCTP_SRC_PORTS) {
456		print_ports("spt", einfo->spts[0], einfo->spts[1],
457			einfo->invflags & XT_SCTP_SRC_PORTS,
458			numeric);
459	}
460
461	if (einfo->flags & XT_SCTP_DEST_PORTS) {
462		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
463			einfo->invflags & XT_SCTP_DEST_PORTS,
464			numeric);
465	}
466
467	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
468		/* FIXME: print_chunks() is used in save() where the printing of '!'
469		s taken care of, so we need to do that here as well */
470		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
471			printf("! ");
472		}
473		print_chunks(einfo, numeric);
474	}
475}
476
477static void sctp_save(const void *ip, const struct xt_entry_match *match)
478{
479	const struct xt_sctp_info *einfo =
480		(const struct xt_sctp_info *)match->data;
481
482	if (einfo->flags & XT_SCTP_SRC_PORTS) {
483		if (einfo->invflags & XT_SCTP_SRC_PORTS)
484			printf("! ");
485		if (einfo->spts[0] != einfo->spts[1])
486			printf("--sport %u:%u ",
487			       einfo->spts[0], einfo->spts[1]);
488		else
489			printf("--sport %u ", einfo->spts[0]);
490	}
491
492	if (einfo->flags & XT_SCTP_DEST_PORTS) {
493		if (einfo->invflags & XT_SCTP_DEST_PORTS)
494			printf("! ");
495		if (einfo->dpts[0] != einfo->dpts[1])
496			printf("--dport %u:%u ",
497			       einfo->dpts[0], einfo->dpts[1]);
498		else
499			printf("--dport %u ", einfo->dpts[0]);
500	}
501
502	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
503		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
504			printf("! ");
505		printf("--chunk-types ");
506
507		print_chunks(einfo, 0);
508	}
509}
510
511static struct xtables_match sctp_match = {
512	.name		= "sctp",
513	.family		= NFPROTO_IPV4,
514	.version	= XTABLES_VERSION,
515	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
516	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
517	.help		= sctp_help,
518	.init		= sctp_init,
519	.parse		= sctp_parse,
520	.print		= sctp_print,
521	.save		= sctp_save,
522	.extra_opts	= sctp_opts,
523};
524
525static struct xtables_match sctp_match6 = {
526	.name		= "sctp",
527	.family		= NFPROTO_IPV6,
528	.version	= XTABLES_VERSION,
529	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
530	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
531	.help		= sctp_help,
532	.init		= sctp_init,
533	.parse		= sctp_parse,
534	.print		= sctp_print,
535	.save		= sctp_save,
536	.extra_opts	= sctp_opts,
537};
538
539void _init(void)
540{
541	xtables_register_match(&sctp_match);
542	xtables_register_match(&sctp_match6);
543}
544