libxt_sctp.c revision da580fe55ebf234febf4a8880f53a80870e9088f 
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	memset(einfo, 0, sizeof(struct xt_sctp_info));
39
40	for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
41		einfo->flag_info[i].chunktype = -1;
42	}
43}
44
45static void sctp_help(void)
46{
47	printf(
48"sctp match options\n"
49"[!] --source-port port[:port]                          match source port(s)\n"
50" --sport ...\n"
51"[!] --destination-port port[:port]                     match destination port(s)\n"
52" --dport ...\n"
53"[!] --chunk-types (all|any|none) (chunktype[:flags])+	match if all, any or none of\n"
54"						        chunktypes are present\n"
55"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");
56}
57
58static const struct option sctp_opts[] = {
59	{.name = "source-port",      .has_arg = true, .val = '1'},
60	{.name = "sport",            .has_arg = true, .val = '1'},
61	{.name = "destination-port", .has_arg = true, .val = '2'},
62	{.name = "dport",            .has_arg = true, .val = '2'},
63	{.name = "chunk-types",      .has_arg = true, .val = '3'},
64	XT_GETOPT_TABLEEND,
65};
66
67static void
68parse_sctp_ports(const char *portstring,
69		 uint16_t *ports)
70{
71	char *buffer;
72	char *cp;
73
74	buffer = strdup(portstring);
75	DEBUGP("%s\n", portstring);
76	if ((cp = strchr(buffer, ':')) == NULL) {
77		ports[0] = ports[1] = xtables_parse_port(buffer, "sctp");
78	}
79	else {
80		*cp = '\0';
81		cp++;
82
83		ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0;
84		ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF;
85
86		if (ports[0] > ports[1])
87			xtables_error(PARAMETER_PROBLEM,
88				   "invalid portrange (min > max)");
89	}
90	free(buffer);
91}
92
93struct sctp_chunk_names {
94	const char *name;
95	unsigned int chunk_type;
96	const char *valid_flags;
97};
98
99/*'ALL' and 'NONE' will be treated specially. */
100static const struct sctp_chunk_names sctp_chunk_names[]
101= { { .name = "DATA", 		.chunk_type = 0,   .valid_flags = "----IUBE"},
102    { .name = "INIT", 		.chunk_type = 1,   .valid_flags = "--------"},
103    { .name = "INIT_ACK", 	.chunk_type = 2,   .valid_flags = "--------"},
104    { .name = "SACK",		.chunk_type = 3,   .valid_flags = "--------"},
105    { .name = "HEARTBEAT",	.chunk_type = 4,   .valid_flags = "--------"},
106    { .name = "HEARTBEAT_ACK",	.chunk_type = 5,   .valid_flags = "--------"},
107    { .name = "ABORT",		.chunk_type = 6,   .valid_flags = "-------T"},
108    { .name = "SHUTDOWN",	.chunk_type = 7,   .valid_flags = "--------"},
109    { .name = "SHUTDOWN_ACK",	.chunk_type = 8,   .valid_flags = "--------"},
110    { .name = "ERROR",		.chunk_type = 9,   .valid_flags = "--------"},
111    { .name = "COOKIE_ECHO",	.chunk_type = 10,  .valid_flags = "--------"},
112    { .name = "COOKIE_ACK",	.chunk_type = 11,  .valid_flags = "--------"},
113    { .name = "ECN_ECNE",	.chunk_type = 12,  .valid_flags = "--------"},
114    { .name = "ECN_CWR",	.chunk_type = 13,  .valid_flags = "--------"},
115    { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
116    { .name = "ASCONF",		.chunk_type = 193,  .valid_flags = "--------"},
117    { .name = "ASCONF_ACK",	.chunk_type = 128,  .valid_flags = "--------"},
118    { .name = "FORWARD_TSN",	.chunk_type = 192,  .valid_flags = "--------"},
119};
120
121static void
122save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
123		     int *flag_count,
124		     int chunktype,
125		     int bit,
126		     int set)
127{
128	int i;
129
130	for (i = 0; i < *flag_count; i++) {
131		if (flag_info[i].chunktype == chunktype) {
132			DEBUGP("Previous match found\n");
133			flag_info[i].chunktype = chunktype;
134			flag_info[i].flag_mask |= (1 << bit);
135			if (set) {
136				flag_info[i].flag |= (1 << bit);
137			}
138
139			return;
140		}
141	}
142
143	if (*flag_count == XT_NUM_SCTP_FLAGS) {
144		xtables_error (PARAMETER_PROBLEM,
145			"Number of chunk types with flags exceeds currently allowed limit."
146			"Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
147			"recompiling both the kernel space and user space modules\n");
148	}
149
150	flag_info[*flag_count].chunktype = chunktype;
151	flag_info[*flag_count].flag_mask |= (1 << bit);
152	if (set) {
153		flag_info[*flag_count].flag |= (1 << bit);
154	}
155	(*flag_count)++;
156}
157
158static void
159parse_sctp_chunk(struct xt_sctp_info *einfo,
160		 const char *chunks)
161{
162	char *ptr;
163	char *buffer;
164	unsigned int i, j;
165	int found = 0;
166	char *chunk_flags;
167
168	buffer = strdup(chunks);
169	DEBUGP("Buffer: %s\n", buffer);
170
171	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
172
173	if (!strcasecmp(buffer, "ALL")) {
174		SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
175		goto out;
176	}
177
178	if (!strcasecmp(buffer, "NONE")) {
179		SCTP_CHUNKMAP_RESET(einfo->chunkmap);
180		goto out;
181	}
182
183	for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
184		found = 0;
185		DEBUGP("Next Chunk type %s\n", ptr);
186
187		if ((chunk_flags = strchr(ptr, ':')) != NULL) {
188			*chunk_flags++ = 0;
189		}
190
191		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
192			if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
193				DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
194				SCTP_CHUNKMAP_SET(einfo->chunkmap,
195					sctp_chunk_names[i].chunk_type);
196				found = 1;
197				break;
198			}
199		if (!found)
200			xtables_error(PARAMETER_PROBLEM,
201				   "Unknown sctp chunk `%s'", ptr);
202
203		if (chunk_flags) {
204			DEBUGP("Chunk flags %s\n", chunk_flags);
205			for (j = 0; j < strlen(chunk_flags); j++) {
206				char *p;
207				int bit;
208
209				if ((p = strchr(sctp_chunk_names[i].valid_flags,
210						toupper(chunk_flags[j]))) != NULL) {
211					bit = p - sctp_chunk_names[i].valid_flags;
212					bit = 7 - bit;
213
214					save_chunk_flag_info(einfo->flag_info,
215						&(einfo->flag_count), i, bit,
216						isupper(chunk_flags[j]));
217				} else {
218					xtables_error(PARAMETER_PROBLEM,
219						"Invalid flags for chunk type %d\n", i);
220				}
221			}
222		}
223	}
224out:
225	free(buffer);
226}
227
228static void
229parse_sctp_chunks(struct xt_sctp_info *einfo,
230		  const char *match_type,
231		  const char *chunks)
232{
233	DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
234	if (!strcasecmp(match_type, "ANY")) {
235		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
236	} else 	if (!strcasecmp(match_type, "ALL")) {
237		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
238	} else 	if (!strcasecmp(match_type, "ONLY")) {
239		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
240	} else {
241		xtables_error (PARAMETER_PROBLEM,
242			"Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
243	}
244
245	SCTP_CHUNKMAP_RESET(einfo->chunkmap);
246	parse_sctp_chunk(einfo, chunks);
247}
248
249static int
250sctp_parse(int c, char **argv, int invert, unsigned int *flags,
251           const void *entry, struct xt_entry_match **match)
252{
253	struct xt_sctp_info *einfo
254		= (struct xt_sctp_info *)(*match)->data;
255
256	switch (c) {
257	case '1':
258		if (*flags & XT_SCTP_SRC_PORTS)
259			xtables_error(PARAMETER_PROBLEM,
260			           "Only one `--source-port' allowed");
261		einfo->flags |= XT_SCTP_SRC_PORTS;
262		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
263		parse_sctp_ports(optarg, einfo->spts);
264		if (invert)
265			einfo->invflags |= XT_SCTP_SRC_PORTS;
266		*flags |= XT_SCTP_SRC_PORTS;
267		break;
268
269	case '2':
270		if (*flags & XT_SCTP_DEST_PORTS)
271			xtables_error(PARAMETER_PROBLEM,
272				   "Only one `--destination-port' allowed");
273		einfo->flags |= XT_SCTP_DEST_PORTS;
274		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
275		parse_sctp_ports(optarg, einfo->dpts);
276		if (invert)
277			einfo->invflags |= XT_SCTP_DEST_PORTS;
278		*flags |= XT_SCTP_DEST_PORTS;
279		break;
280
281	case '3':
282		if (*flags & XT_SCTP_CHUNK_TYPES)
283			xtables_error(PARAMETER_PROBLEM,
284				   "Only one `--chunk-types' allowed");
285		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
286
287		if (!argv[optind]
288		    || argv[optind][0] == '-' || argv[optind][0] == '!')
289			xtables_error(PARAMETER_PROBLEM,
290				   "--chunk-types requires two args");
291
292		einfo->flags |= XT_SCTP_CHUNK_TYPES;
293		parse_sctp_chunks(einfo, optarg, argv[optind]);
294		if (invert)
295			einfo->invflags |= XT_SCTP_CHUNK_TYPES;
296		optind++;
297		*flags |= XT_SCTP_CHUNK_TYPES;
298		break;
299	}
300	return 1;
301}
302
303static char *
304port_to_service(int port)
305{
306	struct servent *service;
307
308	if ((service = getservbyport(htons(port), "sctp")))
309		return service->s_name;
310
311	return NULL;
312}
313
314static void
315print_port(uint16_t port, int numeric)
316{
317	char *service;
318
319	if (numeric || (service = port_to_service(port)) == NULL)
320		printf("%u", port);
321	else
322		printf("%s", service);
323}
324
325static void
326print_ports(const char *name, uint16_t min, uint16_t max,
327	    int invert, int numeric)
328{
329	const char *inv = invert ? "!" : "";
330
331	if (min != 0 || max != 0xFFFF || invert) {
332		printf("%s", name);
333		if (min == max) {
334			printf(":%s", inv);
335			print_port(min, numeric);
336		} else {
337			printf("s:%s", inv);
338			print_port(min, numeric);
339			printf(":");
340			print_port(max, numeric);
341		}
342		printf(" ");
343	}
344}
345
346static void
347print_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask)
348{
349	int i;
350
351	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
352			chunk_flags_mask);
353
354	if (chunk_flags_mask) {
355		printf(":");
356	}
357
358	for (i = 7; i >= 0; i--) {
359		if (chunk_flags_mask & (1 << i)) {
360			if (chunk_flags & (1 << i)) {
361				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
362			} else {
363				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
364			}
365		}
366	}
367}
368
369static void
370print_chunk(uint32_t chunknum, int numeric)
371{
372	if (numeric) {
373		printf("0x%04X", chunknum);
374	}
375	else {
376		int i;
377
378		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
379			if (sctp_chunk_names[i].chunk_type == chunknum)
380				printf("%s", sctp_chunk_names[chunknum].name);
381	}
382}
383
384static void
385print_chunks(const struct xt_sctp_info *einfo, int numeric)
386{
387	uint32_t chunk_match_type = einfo->chunk_match_type;
388	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
389	int flag_count = einfo->flag_count;
390	int i, j;
391	int flag;
392
393	switch (chunk_match_type) {
394		case SCTP_CHUNK_MATCH_ANY:	printf("any "); break;
395		case SCTP_CHUNK_MATCH_ALL:	printf("all "); break;
396		case SCTP_CHUNK_MATCH_ONLY:	printf("only "); break;
397		default:	printf("Never reach here\n"); break;
398	}
399
400	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
401		printf("NONE ");
402		goto out;
403	}
404
405	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
406		printf("ALL ");
407		goto out;
408	}
409
410	flag = 0;
411	for (i = 0; i < 256; i++) {
412		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
413			if (flag)
414				printf(",");
415			flag = 1;
416			print_chunk(i, numeric);
417			for (j = 0; j < flag_count; j++) {
418				if (flag_info[j].chunktype == i) {
419					print_chunk_flags(i, flag_info[j].flag,
420						flag_info[j].flag_mask);
421				}
422			}
423		}
424	}
425
426	if (flag)
427		printf(" ");
428out:
429	return;
430}
431
432static void
433sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
434{
435	const struct xt_sctp_info *einfo =
436		(const struct xt_sctp_info *)match->data;
437
438	printf("sctp ");
439
440	if (einfo->flags & XT_SCTP_SRC_PORTS) {
441		print_ports("spt", einfo->spts[0], einfo->spts[1],
442			einfo->invflags & XT_SCTP_SRC_PORTS,
443			numeric);
444	}
445
446	if (einfo->flags & XT_SCTP_DEST_PORTS) {
447		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
448			einfo->invflags & XT_SCTP_DEST_PORTS,
449			numeric);
450	}
451
452	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
453		/* FIXME: print_chunks() is used in save() where the printing of '!'
454		s taken care of, so we need to do that here as well */
455		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
456			printf("! ");
457		}
458		print_chunks(einfo, numeric);
459	}
460}
461
462static void sctp_save(const void *ip, const struct xt_entry_match *match)
463{
464	const struct xt_sctp_info *einfo =
465		(const struct xt_sctp_info *)match->data;
466
467	if (einfo->flags & XT_SCTP_SRC_PORTS) {
468		if (einfo->invflags & XT_SCTP_SRC_PORTS)
469			printf("! ");
470		if (einfo->spts[0] != einfo->spts[1])
471			printf("--sport %u:%u ",
472			       einfo->spts[0], einfo->spts[1]);
473		else
474			printf("--sport %u ", einfo->spts[0]);
475	}
476
477	if (einfo->flags & XT_SCTP_DEST_PORTS) {
478		if (einfo->invflags & XT_SCTP_DEST_PORTS)
479			printf("! ");
480		if (einfo->dpts[0] != einfo->dpts[1])
481			printf("--dport %u:%u ",
482			       einfo->dpts[0], einfo->dpts[1]);
483		else
484			printf("--dport %u ", einfo->dpts[0]);
485	}
486
487	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
488		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
489			printf("! ");
490		printf("--chunk-types ");
491
492		print_chunks(einfo, 0);
493	}
494}
495
496static struct xtables_match sctp_match = {
497	.name		= "sctp",
498	.family		= NFPROTO_UNSPEC,
499	.version	= XTABLES_VERSION,
500	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
501	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
502	.help		= sctp_help,
503	.init		= sctp_init,
504	.parse		= sctp_parse,
505	.print		= sctp_print,
506	.save		= sctp_save,
507	.extra_opts	= sctp_opts,
508};
509
510void _init(void)
511{
512	xtables_register_match(&sctp_match);
513}
514