libxt_sctp.c revision c5e85736c207f211d82d2878a5781f512327dfce 
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#include <linux/netfilter/xt_sctp.h>
21
22#if 0
23#define DEBUGP(format, first...) printf(format, ##first)
24#define static
25#else
26#define DEBUGP(format, fist...)
27#endif
28
29static void
30print_chunk(u_int32_t chunknum, int numeric);
31
32static void sctp_init(struct xt_entry_match *m)
33{
34	int i;
35	struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
36
37	memset(einfo, 0, sizeof(struct xt_sctp_info));
38
39	for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
40		einfo->flag_info[i].chunktype = -1;
41	}
42}
43
44static void sctp_help(void)
45{
46	printf(
47"sctp match options\n"
48"[!] --source-port port[:port]                          match source port(s)\n"
49" --sport ...\n"
50"[!] --destination-port port[:port]                     match destination port(s)\n"
51" --dport ...\n"
52"[!] --chunk-types (all|any|none) (chunktype[:flags])+	match if all, any or none of\n"
53"						        chunktypes are present\n"
54"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");
55}
56
57static const struct option sctp_opts[] = {
58	{ .name = "source-port", .has_arg = 1, .val = '1' },
59	{ .name = "sport", .has_arg = 1, .val = '1' },
60	{ .name = "destination-port", .has_arg = 1, .val = '2' },
61	{ .name = "dport", .has_arg = 1, .val = '2' },
62	{ .name = "chunk-types", .has_arg = 1, .val = '3' },
63	{ .name = NULL }
64};
65
66static void
67parse_sctp_ports(const char *portstring,
68		 u_int16_t *ports)
69{
70	char *buffer;
71	char *cp;
72
73	buffer = strdup(portstring);
74	DEBUGP("%s\n", portstring);
75	if ((cp = strchr(buffer, ':')) == NULL) {
76		ports[0] = ports[1] = xtables_parse_port(buffer, "sctp");
77	}
78	else {
79		*cp = '\0';
80		cp++;
81
82		ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0;
83		ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF;
84
85		if (ports[0] > ports[1])
86			xtables_error(PARAMETER_PROBLEM,
87				   "invalid portrange (min > max)");
88	}
89	free(buffer);
90}
91
92struct sctp_chunk_names {
93	const char *name;
94	unsigned int chunk_type;
95	const char *valid_flags;
96};
97
98/*'ALL' and 'NONE' will be treated specially. */
99static const struct sctp_chunk_names sctp_chunk_names[]
100= { { .name = "DATA", 		.chunk_type = 0,   .valid_flags = "-----UBE"},
101    { .name = "INIT", 		.chunk_type = 1,   .valid_flags = "--------"},
102    { .name = "INIT_ACK", 	.chunk_type = 2,   .valid_flags = "--------"},
103    { .name = "SACK",		.chunk_type = 3,   .valid_flags = "--------"},
104    { .name = "HEARTBEAT",	.chunk_type = 4,   .valid_flags = "--------"},
105    { .name = "HEARTBEAT_ACK",	.chunk_type = 5,   .valid_flags = "--------"},
106    { .name = "ABORT",		.chunk_type = 6,   .valid_flags = "-------T"},
107    { .name = "SHUTDOWN",	.chunk_type = 7,   .valid_flags = "--------"},
108    { .name = "SHUTDOWN_ACK",	.chunk_type = 8,   .valid_flags = "--------"},
109    { .name = "ERROR",		.chunk_type = 9,   .valid_flags = "--------"},
110    { .name = "COOKIE_ECHO",	.chunk_type = 10,  .valid_flags = "--------"},
111    { .name = "COOKIE_ACK",	.chunk_type = 11,  .valid_flags = "--------"},
112    { .name = "ECN_ECNE",	.chunk_type = 12,  .valid_flags = "--------"},
113    { .name = "ECN_CWR",	.chunk_type = 13,  .valid_flags = "--------"},
114    { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
115    { .name = "ASCONF",		.chunk_type = 193,  .valid_flags = "--------"},
116    { .name = "ASCONF_ACK",	.chunk_type = 128,  .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);
261		parse_sctp_ports(argv[optind-1], 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);
273		parse_sctp_ports(argv[optind-1], 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);
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, argv[optind-1], argv[optind]);
292		if (invert)
293			einfo->invflags |= XT_SCTP_CHUNK_TYPES;
294		optind++;
295		*flags |= XT_SCTP_CHUNK_TYPES;
296		break;
297
298	default:
299		return 0;
300	}
301	return 1;
302}
303
304static char *
305port_to_service(int port)
306{
307	struct servent *service;
308
309	if ((service = getservbyport(htons(port), "sctp")))
310		return service->s_name;
311
312	return NULL;
313}
314
315static void
316print_port(u_int16_t port, int numeric)
317{
318	char *service;
319
320	if (numeric || (service = port_to_service(port)) == NULL)
321		printf("%u", port);
322	else
323		printf("%s", service);
324}
325
326static void
327print_ports(const char *name, u_int16_t min, u_int16_t max,
328	    int invert, int numeric)
329{
330	const char *inv = invert ? "!" : "";
331
332	if (min != 0 || max != 0xFFFF || invert) {
333		printf("%s", name);
334		if (min == max) {
335			printf(":%s", inv);
336			print_port(min, numeric);
337		} else {
338			printf("s:%s", inv);
339			print_port(min, numeric);
340			printf(":");
341			print_port(max, numeric);
342		}
343		printf(" ");
344	}
345}
346
347static void
348print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
349{
350	int i;
351
352	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
353			chunk_flags_mask);
354
355	if (chunk_flags_mask) {
356		printf(":");
357	}
358
359	for (i = 7; i >= 0; i--) {
360		if (chunk_flags_mask & (1 << i)) {
361			if (chunk_flags & (1 << i)) {
362				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
363			} else {
364				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
365			}
366		}
367	}
368}
369
370static void
371print_chunk(u_int32_t chunknum, int numeric)
372{
373	if (numeric) {
374		printf("0x%04X", chunknum);
375	}
376	else {
377		int i;
378
379		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
380			if (sctp_chunk_names[i].chunk_type == chunknum)
381				printf("%s", sctp_chunk_names[chunknum].name);
382	}
383}
384
385static void
386print_chunks(const struct xt_sctp_info *einfo, int numeric)
387{
388	u_int32_t chunk_match_type = einfo->chunk_match_type;
389	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
390	int flag_count = einfo->flag_count;
391	int i, j;
392	int flag;
393
394	switch (chunk_match_type) {
395		case SCTP_CHUNK_MATCH_ANY:	printf("any "); break;
396		case SCTP_CHUNK_MATCH_ALL:	printf("all "); break;
397		case SCTP_CHUNK_MATCH_ONLY:	printf("only "); break;
398		default:	printf("Never reach herer\n"); break;
399	}
400
401	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
402		printf("NONE ");
403		goto out;
404	}
405
406	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
407		printf("ALL ");
408		goto out;
409	}
410
411	flag = 0;
412	for (i = 0; i < 256; i++) {
413		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
414			if (flag)
415				printf(",");
416			flag = 1;
417			print_chunk(i, numeric);
418			for (j = 0; j < flag_count; j++) {
419				if (flag_info[j].chunktype == i) {
420					print_chunk_flags(i, flag_info[j].flag,
421						flag_info[j].flag_mask);
422				}
423			}
424		}
425	}
426
427	if (flag)
428		printf(" ");
429out:
430	return;
431}
432
433static void
434sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
435{
436	const struct xt_sctp_info *einfo =
437		(const struct xt_sctp_info *)match->data;
438
439	printf("sctp ");
440
441	if (einfo->flags & XT_SCTP_SRC_PORTS) {
442		print_ports("spt", einfo->spts[0], einfo->spts[1],
443			einfo->invflags & XT_SCTP_SRC_PORTS,
444			numeric);
445	}
446
447	if (einfo->flags & XT_SCTP_DEST_PORTS) {
448		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
449			einfo->invflags & XT_SCTP_DEST_PORTS,
450			numeric);
451	}
452
453	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
454		/* FIXME: print_chunks() is used in save() where the printing of '!'
455		s taken care of, so we need to do that here as well */
456		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
457			printf("! ");
458		}
459		print_chunks(einfo, numeric);
460	}
461}
462
463static void sctp_save(const void *ip, const struct xt_entry_match *match)
464{
465	const struct xt_sctp_info *einfo =
466		(const struct xt_sctp_info *)match->data;
467
468	if (einfo->flags & XT_SCTP_SRC_PORTS) {
469		if (einfo->invflags & XT_SCTP_SRC_PORTS)
470			printf("! ");
471		if (einfo->spts[0] != einfo->spts[1])
472			printf("--sport %u:%u ",
473			       einfo->spts[0], einfo->spts[1]);
474		else
475			printf("--sport %u ", einfo->spts[0]);
476	}
477
478	if (einfo->flags & XT_SCTP_DEST_PORTS) {
479		if (einfo->invflags & XT_SCTP_DEST_PORTS)
480			printf("! ");
481		if (einfo->dpts[0] != einfo->dpts[1])
482			printf("--dport %u:%u ",
483			       einfo->dpts[0], einfo->dpts[1]);
484		else
485			printf("--dport %u ", einfo->dpts[0]);
486	}
487
488	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
489		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
490			printf("! ");
491		printf("--chunk-types ");
492
493		print_chunks(einfo, 0);
494	}
495}
496
497static struct xtables_match sctp_match = {
498	.name		= "sctp",
499	.family		= NFPROTO_UNSPEC,
500	.version	= XTABLES_VERSION,
501	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
502	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
503	.help		= sctp_help,
504	.init		= sctp_init,
505	.parse		= sctp_parse,
506	.print		= sctp_print,
507	.save		= sctp_save,
508	.extra_opts	= sctp_opts,
509};
510
511void _init(void)
512{
513	xtables_register_match(&sctp_match);
514}
515