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		parse_sctp_ports(optarg, einfo->spts);
261		if (invert)
262			einfo->invflags |= XT_SCTP_SRC_PORTS;
263		*flags |= XT_SCTP_SRC_PORTS;
264		break;
265
266	case '2':
267		if (*flags & XT_SCTP_DEST_PORTS)
268			xtables_error(PARAMETER_PROBLEM,
269				   "Only one `--destination-port' allowed");
270		einfo->flags |= XT_SCTP_DEST_PORTS;
271		parse_sctp_ports(optarg, einfo->dpts);
272		if (invert)
273			einfo->invflags |= XT_SCTP_DEST_PORTS;
274		*flags |= XT_SCTP_DEST_PORTS;
275		break;
276
277	case '3':
278		if (*flags & XT_SCTP_CHUNK_TYPES)
279			xtables_error(PARAMETER_PROBLEM,
280				   "Only one `--chunk-types' allowed");
281		if (!argv[optind]
282		    || argv[optind][0] == '-' || argv[optind][0] == '!')
283			xtables_error(PARAMETER_PROBLEM,
284				   "--chunk-types requires two args");
285
286		einfo->flags |= XT_SCTP_CHUNK_TYPES;
287		parse_sctp_chunks(einfo, optarg, argv[optind]);
288		if (invert)
289			einfo->invflags |= XT_SCTP_CHUNK_TYPES;
290		optind++;
291		*flags |= XT_SCTP_CHUNK_TYPES;
292		break;
293	}
294	return 1;
295}
296
297static const char *
298port_to_service(int port)
299{
300	const struct servent *service;
301
302	if ((service = getservbyport(htons(port), "sctp")))
303		return service->s_name;
304
305	return NULL;
306}
307
308static void
309print_port(uint16_t port, int numeric)
310{
311	const char *service;
312
313	if (numeric || (service = port_to_service(port)) == NULL)
314		printf("%u", port);
315	else
316		printf("%s", service);
317}
318
319static void
320print_ports(const char *name, uint16_t min, uint16_t max,
321	    int invert, int numeric)
322{
323	const char *inv = invert ? "!" : "";
324
325	if (min != 0 || max != 0xFFFF || invert) {
326		printf(" %s", name);
327		if (min == max) {
328			printf(":%s", inv);
329			print_port(min, numeric);
330		} else {
331			printf("s:%s", inv);
332			print_port(min, numeric);
333			printf(":");
334			print_port(max, numeric);
335		}
336	}
337}
338
339static void
340print_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask)
341{
342	int i;
343
344	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
345			chunk_flags_mask);
346
347	if (chunk_flags_mask) {
348		printf(":");
349	}
350
351	for (i = 7; i >= 0; i--) {
352		if (chunk_flags_mask & (1 << i)) {
353			if (chunk_flags & (1 << i)) {
354				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
355			} else {
356				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
357			}
358		}
359	}
360}
361
362static void
363print_chunk(uint32_t chunknum, int numeric)
364{
365	if (numeric) {
366		printf("0x%04X", chunknum);
367	}
368	else {
369		int i;
370
371		for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
372			if (sctp_chunk_names[i].chunk_type == chunknum)
373				printf("%s", sctp_chunk_names[chunknum].name);
374	}
375}
376
377static void
378print_chunks(const struct xt_sctp_info *einfo, int numeric)
379{
380	uint32_t chunk_match_type = einfo->chunk_match_type;
381	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
382	int flag_count = einfo->flag_count;
383	int i, j;
384	int flag;
385
386	switch (chunk_match_type) {
387		case SCTP_CHUNK_MATCH_ANY:	printf(" any"); break;
388		case SCTP_CHUNK_MATCH_ALL:	printf(" all"); break;
389		case SCTP_CHUNK_MATCH_ONLY:	printf(" only"); break;
390		default:	printf("Never reach here\n"); break;
391	}
392
393	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
394		printf(" NONE");
395		goto out;
396	}
397
398	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
399		printf(" ALL");
400		goto out;
401	}
402
403	flag = 0;
404	for (i = 0; i < 256; i++) {
405		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
406			if (flag)
407				printf(",");
408			else
409				putchar(' ');
410			flag = 1;
411			print_chunk(i, numeric);
412			for (j = 0; j < flag_count; j++) {
413				if (flag_info[j].chunktype == i) {
414					print_chunk_flags(i, flag_info[j].flag,
415						flag_info[j].flag_mask);
416				}
417			}
418		}
419	}
420out:
421	return;
422}
423
424static void
425sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
426{
427	const struct xt_sctp_info *einfo =
428		(const struct xt_sctp_info *)match->data;
429
430	printf(" sctp");
431
432	if (einfo->flags & XT_SCTP_SRC_PORTS) {
433		print_ports("spt", einfo->spts[0], einfo->spts[1],
434			einfo->invflags & XT_SCTP_SRC_PORTS,
435			numeric);
436	}
437
438	if (einfo->flags & XT_SCTP_DEST_PORTS) {
439		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
440			einfo->invflags & XT_SCTP_DEST_PORTS,
441			numeric);
442	}
443
444	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
445		/* FIXME: print_chunks() is used in save() where the printing of '!'
446		s taken care of, so we need to do that here as well */
447		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
448			printf(" !");
449		}
450		print_chunks(einfo, numeric);
451	}
452}
453
454static void sctp_save(const void *ip, const struct xt_entry_match *match)
455{
456	const struct xt_sctp_info *einfo =
457		(const struct xt_sctp_info *)match->data;
458
459	if (einfo->flags & XT_SCTP_SRC_PORTS) {
460		if (einfo->invflags & XT_SCTP_SRC_PORTS)
461			printf(" !");
462		if (einfo->spts[0] != einfo->spts[1])
463			printf(" --sport %u:%u",
464			       einfo->spts[0], einfo->spts[1]);
465		else
466			printf(" --sport %u", einfo->spts[0]);
467	}
468
469	if (einfo->flags & XT_SCTP_DEST_PORTS) {
470		if (einfo->invflags & XT_SCTP_DEST_PORTS)
471			printf(" !");
472		if (einfo->dpts[0] != einfo->dpts[1])
473			printf(" --dport %u:%u",
474			       einfo->dpts[0], einfo->dpts[1]);
475		else
476			printf(" --dport %u", einfo->dpts[0]);
477	}
478
479	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
480		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
481			printf(" !");
482		printf(" --chunk-types");
483
484		print_chunks(einfo, 0);
485	}
486}
487
488static struct xtables_match sctp_match = {
489	.name		= "sctp",
490	.family		= NFPROTO_UNSPEC,
491	.version	= XTABLES_VERSION,
492	.size		= XT_ALIGN(sizeof(struct xt_sctp_info)),
493	.userspacesize	= XT_ALIGN(sizeof(struct xt_sctp_info)),
494	.help		= sctp_help,
495	.init		= sctp_init,
496	.parse		= sctp_parse,
497	.print		= sctp_print,
498	.save		= sctp_save,
499	.extra_opts	= sctp_opts,
500};
501
502void _init(void)
503{
504	xtables_register_match(&sctp_match);
505}
506