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 <ip6tables.h>
18 #include <linux/netfilter_ipv6/ip6_tables.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 userserspace,
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
41 static void
42 print_chunk(u_int32_t chunknum, int numeric);
43
44 /* Initialize the match. */
45 static void
init(struct ip6t_entry_match * m,unsigned int * nfcache)46 init(struct ip6t_entry_match *m,
47 unsigned int *nfcache)
48 {
49 int i;
50 struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
51
52 memset(einfo, 0, sizeof(struct xt_sctp_info));
53
54 for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
55 einfo->flag_info[i].chunktype = -1;
56 }
57 }
58
help(void)59 static void help(void)
60 {
61 printf(
62 "SCTP match v%s options\n"
63 " --source-port [!] port[:port] match source port(s)\n"
64 " --sport ...\n"
65 " --destination-port [!] port[:port] match destination port(s)\n"
66 " --dport ...\n"
67 " --chunk-types [!] (all|any|none) (chunktype[:flags])+ match if all, any or none of\n"
68 " chunktypes are present\n"
69 "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",
70 IPTABLES_VERSION);
71 }
72
73 static struct option opts[] = {
74 { .name = "source-port", .has_arg = 1, .flag = 0, .val = '1' },
75 { .name = "sport", .has_arg = 1, .flag = 0, .val = '1' },
76 { .name = "destination-port", .has_arg = 1, .flag = 0, .val = '2' },
77 { .name = "dport", .has_arg = 1, .flag = 0, .val = '2' },
78 { .name = "chunk-types", .has_arg = 1, .flag = 0, .val = '3' },
79 { .name = 0 }
80 };
81
82 static void
parse_sctp_ports(const char * portstring,u_int16_t * ports)83 parse_sctp_ports(const char *portstring,
84 u_int16_t *ports)
85 {
86 char *buffer;
87 char *cp;
88
89 buffer = strdup(portstring);
90 DEBUGP("%s\n", portstring);
91 if ((cp = strchr(buffer, ':')) == NULL) {
92 ports[0] = ports[1] = parse_port(buffer, "sctp");
93 }
94 else {
95 *cp = '\0';
96 cp++;
97
98 ports[0] = buffer[0] ? parse_port(buffer, "sctp") : 0;
99 ports[1] = cp[0] ? parse_port(cp, "sctp") : 0xFFFF;
100
101 if (ports[0] > ports[1])
102 exit_error(PARAMETER_PROBLEM,
103 "invalid portrange (min > max)");
104 }
105 free(buffer);
106 }
107
108 struct sctp_chunk_names {
109 const char *name;
110 unsigned int chunk_type;
111 const char *valid_flags;
112 };
113
114 /*'ALL' and 'NONE' will be treated specially. */
115 static struct sctp_chunk_names sctp_chunk_names[]
116 = { { .name = "DATA", .chunk_type = 0, .valid_flags = "-----UBE"},
117 { .name = "INIT", .chunk_type = 1, .valid_flags = "--------"},
118 { .name = "INIT_ACK", .chunk_type = 2, .valid_flags = "--------"},
119 { .name = "SACK", .chunk_type = 3, .valid_flags = "--------"},
120 { .name = "HEARTBEAT", .chunk_type = 4, .valid_flags = "--------"},
121 { .name = "HEARTBEAT_ACK", .chunk_type = 5, .valid_flags = "--------"},
122 { .name = "ABORT", .chunk_type = 6, .valid_flags = "-------T"},
123 { .name = "SHUTDOWN", .chunk_type = 7, .valid_flags = "--------"},
124 { .name = "SHUTDOWN_ACK", .chunk_type = 8, .valid_flags = "--------"},
125 { .name = "ERROR", .chunk_type = 9, .valid_flags = "--------"},
126 { .name = "COOKIE_ECHO", .chunk_type = 10, .valid_flags = "--------"},
127 { .name = "COOKIE_ACK", .chunk_type = 11, .valid_flags = "--------"},
128 { .name = "ECN_ECNE", .chunk_type = 12, .valid_flags = "--------"},
129 { .name = "ECN_CWR", .chunk_type = 13, .valid_flags = "--------"},
130 { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14, .valid_flags = "-------T"},
131 { .name = "ASCONF", .chunk_type = 31, .valid_flags = "--------"},
132 { .name = "ASCONF_ACK", .chunk_type = 30, .valid_flags = "--------"},
133 };
134
135 static void
save_chunk_flag_info(struct xt_sctp_flag_info * flag_info,int * flag_count,int chunktype,int bit,int set)136 save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
137 int *flag_count,
138 int chunktype,
139 int bit,
140 int set)
141 {
142 int i;
143
144 for (i = 0; i < *flag_count; i++) {
145 if (flag_info[i].chunktype == chunktype) {
146 DEBUGP("Previous match found\n");
147 flag_info[i].chunktype = chunktype;
148 flag_info[i].flag_mask |= (1 << bit);
149 if (set) {
150 flag_info[i].flag |= (1 << bit);
151 }
152
153 return;
154 }
155 }
156
157 if (*flag_count == XT_NUM_SCTP_FLAGS) {
158 exit_error (PARAMETER_PROBLEM,
159 "Number of chunk types with flags exceeds currently allowed limit."
160 "Increasing this limit involves changing XT_NUM_SCTP_FLAGS and"
161 "recompiling both the kernel space and user space modules\n");
162 }
163
164 flag_info[*flag_count].chunktype = chunktype;
165 flag_info[*flag_count].flag_mask |= (1 << bit);
166 if (set) {
167 flag_info[*flag_count].flag |= (1 << bit);
168 }
169 (*flag_count)++;
170 }
171
172 static void
parse_sctp_chunk(struct xt_sctp_info * einfo,const char * chunks)173 parse_sctp_chunk(struct xt_sctp_info *einfo,
174 const char *chunks)
175 {
176 char *ptr;
177 char *buffer;
178 unsigned int i, j;
179 int found = 0;
180 char *chunk_flags;
181
182 buffer = strdup(chunks);
183 DEBUGP("Buffer: %s\n", buffer);
184
185 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
186
187 if (!strcasecmp(buffer, "ALL")) {
188 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
189 goto out;
190 }
191
192 if (!strcasecmp(buffer, "NONE")) {
193 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
194 goto out;
195 }
196
197 for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
198 found = 0;
199 DEBUGP("Next Chunk type %s\n", ptr);
200
201 if ((chunk_flags = strchr(ptr, ':')) != NULL) {
202 *chunk_flags++ = 0;
203 }
204
205 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
206 if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
207 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
208 SCTP_CHUNKMAP_SET(einfo->chunkmap,
209 sctp_chunk_names[i].chunk_type);
210 found = 1;
211 break;
212 }
213 }
214 if (!found)
215 exit_error(PARAMETER_PROBLEM,
216 "Unknown sctp chunk `%s'", ptr);
217
218 if (chunk_flags) {
219 DEBUGP("Chunk flags %s\n", chunk_flags);
220 for (j = 0; j < strlen(chunk_flags); j++) {
221 char *p;
222 int bit;
223
224 if ((p = strchr(sctp_chunk_names[i].valid_flags,
225 toupper(chunk_flags[j]))) != NULL) {
226 bit = p - sctp_chunk_names[i].valid_flags;
227 bit = 7 - bit;
228
229 save_chunk_flag_info(einfo->flag_info,
230 &(einfo->flag_count), i, bit,
231 isupper(chunk_flags[j]));
232 } else {
233 exit_error(PARAMETER_PROBLEM,
234 "Invalid flags for chunk type %d\n", i);
235 }
236 }
237 }
238 }
239 out:
240 free(buffer);
241 }
242
243 static void
parse_sctp_chunks(struct xt_sctp_info * einfo,const char * match_type,const char * chunks)244 parse_sctp_chunks(struct xt_sctp_info *einfo,
245 const char *match_type,
246 const char *chunks)
247 {
248 DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
249 if (!strcasecmp(match_type, "ANY")) {
250 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
251 } else if (!strcasecmp(match_type, "ALL")) {
252 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
253 } else if (!strcasecmp(match_type, "ONLY")) {
254 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
255 } else {
256 exit_error (PARAMETER_PROBLEM,
257 "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
258 }
259
260 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
261 parse_sctp_chunk(einfo, chunks);
262 }
263
264 static int
parse(int c,char ** argv,int invert,unsigned int * flags,const struct ip6t_entry * entry,unsigned int * nfcache,struct ip6t_entry_match ** match)265 parse(int c, char **argv, int invert, unsigned int *flags,
266 const struct ip6t_entry *entry,
267 unsigned int *nfcache,
268 struct ip6t_entry_match **match)
269 {
270 struct xt_sctp_info *einfo
271 = (struct xt_sctp_info *)(*match)->data;
272
273 switch (c) {
274 case '1':
275 if (*flags & XT_SCTP_SRC_PORTS)
276 exit_error(PARAMETER_PROBLEM,
277 "Only one `--source-port' allowed");
278 einfo->flags |= XT_SCTP_SRC_PORTS;
279 check_inverse(optarg, &invert, &optind, 0);
280 parse_sctp_ports(argv[optind-1], einfo->spts);
281 if (invert)
282 einfo->invflags |= XT_SCTP_SRC_PORTS;
283 *flags |= XT_SCTP_SRC_PORTS;
284 break;
285
286 case '2':
287 if (*flags & XT_SCTP_DEST_PORTS)
288 exit_error(PARAMETER_PROBLEM,
289 "Only one `--destination-port' allowed");
290 einfo->flags |= XT_SCTP_DEST_PORTS;
291 check_inverse(optarg, &invert, &optind, 0);
292 parse_sctp_ports(argv[optind-1], einfo->dpts);
293 if (invert)
294 einfo->invflags |= XT_SCTP_DEST_PORTS;
295 *flags |= XT_SCTP_DEST_PORTS;
296 break;
297
298 case '3':
299 if (*flags & XT_SCTP_CHUNK_TYPES)
300 exit_error(PARAMETER_PROBLEM,
301 "Only one `--chunk-types' allowed");
302 check_inverse(optarg, &invert, &optind, 0);
303
304 if (!argv[optind]
305 || argv[optind][0] == '-' || argv[optind][0] == '!')
306 exit_error(PARAMETER_PROBLEM,
307 "--chunk-types requires two args");
308
309 einfo->flags |= XT_SCTP_CHUNK_TYPES;
310 parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
311 if (invert)
312 einfo->invflags |= XT_SCTP_CHUNK_TYPES;
313 optind++;
314 *flags |= XT_SCTP_CHUNK_TYPES;
315 break;
316
317 default:
318 return 0;
319 }
320 return 1;
321 }
322
323 static void
final_check(unsigned int flags)324 final_check(unsigned int flags)
325 {
326 }
327
328 static char *
port_to_service(int port)329 port_to_service(int port)
330 {
331 struct servent *service;
332
333 if ((service = getservbyport(htons(port), "sctp")))
334 return service->s_name;
335
336 return NULL;
337 }
338
339 static void
print_port(u_int16_t port,int numeric)340 print_port(u_int16_t port, int numeric)
341 {
342 char *service;
343
344 if (numeric || (service = port_to_service(port)) == NULL)
345 printf("%u", port);
346 else
347 printf("%s", service);
348 }
349
350 static void
print_ports(const char * name,u_int16_t min,u_int16_t max,int invert,int numeric)351 print_ports(const char *name, u_int16_t min, u_int16_t max,
352 int invert, int numeric)
353 {
354 const char *inv = invert ? "!" : "";
355
356 if (min != 0 || max != 0xFFFF || invert) {
357 printf("%s", name);
358 if (min == max) {
359 printf(":%s", inv);
360 print_port(min, numeric);
361 } else {
362 printf("s:%s", inv);
363 print_port(min, numeric);
364 printf(":");
365 print_port(max, numeric);
366 }
367 printf(" ");
368 }
369 }
370
371 static void
print_chunk_flags(u_int32_t chunknum,u_int8_t chunk_flags,u_int8_t chunk_flags_mask)372 print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
373 {
374 int i;
375
376 DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
377 chunk_flags_mask);
378
379 if (chunk_flags_mask) {
380 printf(":");
381 }
382
383 for (i = 7; i >= 0; i--) {
384 if (chunk_flags_mask & (1 << i)) {
385 if (chunk_flags & (1 << i)) {
386 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
387 } else {
388 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
389 }
390 }
391 }
392 }
393
394 static void
print_chunk(u_int32_t chunknum,int numeric)395 print_chunk(u_int32_t chunknum, int numeric)
396 {
397 if (numeric) {
398 printf("0x%04X", chunknum);
399 }
400 else {
401 int i;
402
403 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
404 if (sctp_chunk_names[i].chunk_type == chunknum)
405 printf("%s", sctp_chunk_names[chunknum].name);
406 }
407 }
408 }
409
410 static void
print_chunks(u_int32_t chunk_match_type,const u_int32_t * chunkmap,const struct xt_sctp_flag_info * flag_info,int flag_count,int numeric)411 print_chunks(u_int32_t chunk_match_type,
412 const u_int32_t *chunkmap,
413 const struct xt_sctp_flag_info *flag_info,
414 int flag_count,
415 int numeric)
416 {
417 int i, j;
418 int flag;
419
420 switch (chunk_match_type) {
421 case SCTP_CHUNK_MATCH_ANY: printf("any "); break;
422 case SCTP_CHUNK_MATCH_ALL: printf("all "); break;
423 case SCTP_CHUNK_MATCH_ONLY: printf("only "); break;
424 default: printf("Never reach herer\n"); break;
425 }
426
427 if (SCTP_CHUNKMAP_IS_CLEAR(chunkmap)) {
428 printf("NONE ");
429 goto out;
430 }
431
432 if (SCTP_CHUNKMAP_IS_ALL_SET(chunkmap)) {
433 printf("ALL ");
434 goto out;
435 }
436
437 flag = 0;
438 for (i = 0; i < 256; i++) {
439 if (SCTP_CHUNKMAP_IS_SET(chunkmap, i)) {
440 if (flag)
441 printf(",");
442 flag = 1;
443 print_chunk(i, numeric);
444 for (j = 0; j < flag_count; j++) {
445 if (flag_info[j].chunktype == i) {
446 print_chunk_flags(i, flag_info[j].flag,
447 flag_info[j].flag_mask);
448 }
449 }
450 }
451 }
452
453 if (flag)
454 printf(" ");
455 out:
456 return;
457 }
458
459 /* Prints out the matchinfo. */
460 static void
print(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match,int numeric)461 print(const struct ip6t_ip6 *ip,
462 const struct ip6t_entry_match *match,
463 int numeric)
464 {
465 const struct xt_sctp_info *einfo =
466 (const struct xt_sctp_info *)match->data;
467
468 printf("sctp ");
469
470 if (einfo->flags & XT_SCTP_SRC_PORTS) {
471 print_ports("spt", einfo->spts[0], einfo->spts[1],
472 einfo->invflags & XT_SCTP_SRC_PORTS,
473 numeric);
474 }
475
476 if (einfo->flags & XT_SCTP_DEST_PORTS) {
477 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
478 einfo->invflags & XT_SCTP_DEST_PORTS,
479 numeric);
480 }
481
482 if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
483 /* FIXME: print_chunks() is used in save() where the printing of '!'
484 s taken care of, so we need to do that here as well */
485 if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
486 printf("! ");
487 }
488 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
489 einfo->flag_info, einfo->flag_count, numeric);
490 }
491 }
492
493 /* Saves the union xt_matchinfo in parsable form to stdout. */
494 static void
save(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match)495 save(const struct ip6t_ip6 *ip,
496 const struct ip6t_entry_match *match)
497 {
498 const struct xt_sctp_info *einfo =
499 (const struct xt_sctp_info *)match->data;
500
501 if (einfo->flags & XT_SCTP_SRC_PORTS) {
502 if (einfo->invflags & XT_SCTP_SRC_PORTS)
503 printf("! ");
504 if (einfo->spts[0] != einfo->spts[1])
505 printf("--sport %u:%u ",
506 einfo->spts[0], einfo->spts[1]);
507 else
508 printf("--sport %u ", einfo->spts[0]);
509 }
510
511 if (einfo->flags & XT_SCTP_DEST_PORTS) {
512 if (einfo->invflags & XT_SCTP_DEST_PORTS)
513 printf("! ");
514 if (einfo->dpts[0] != einfo->dpts[1])
515 printf("--dport %u:%u ",
516 einfo->dpts[0], einfo->dpts[1]);
517 else
518 printf("--dport %u ", einfo->dpts[0]);
519 }
520
521 if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
522 if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
523 printf("! ");
524 printf("--chunk-types ");
525
526 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
527 einfo->flag_info, einfo->flag_count, 0);
528 }
529 }
530
531 static
532 struct ip6tables_match sctp
533 = { .name = "sctp",
534 .version = IPTABLES_VERSION,
535 .size = IP6T_ALIGN(sizeof(struct xt_sctp_info)),
536 .userspacesize = IP6T_ALIGN(sizeof(struct xt_sctp_info)),
537 .help = &help,
538 .init = &init,
539 .parse = &parse,
540 .final_check = &final_check,
541 .print = &print,
542 .save = &save,
543 .extra_opts = opts
544 };
545
_init(void)546 void _init(void)
547 {
548 register_match6(&sctp);
549 }
550
551