diff options
Diffstat (limited to 'src/util/dnsparser.c')
-rw-r--r-- | src/util/dnsparser.c | 1400 |
1 files changed, 0 insertions, 1400 deletions
diff --git a/src/util/dnsparser.c b/src/util/dnsparser.c deleted file mode 100644 index 401723106..000000000 --- a/src/util/dnsparser.c +++ /dev/null | |||
@@ -1,1400 +0,0 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet | ||
3 | Copyright (C) 2010-2014, 2018 GNUnet e.V. | ||
4 | |||
5 | GNUnet is free software: you can redistribute it and/or modify it | ||
6 | under the terms of the GNU Affero General Public License as published | ||
7 | by the Free Software Foundation, either version 3 of the License, | ||
8 | or (at your option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | Affero General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | |||
18 | SPDX-License-Identifier: AGPL3.0-or-later | ||
19 | */ | ||
20 | |||
21 | /** | ||
22 | * @file util/dnsparser.c | ||
23 | * @brief helper library to parse DNS packets. | ||
24 | * @author Philipp Toelke | ||
25 | * @author Christian Grothoff | ||
26 | */ | ||
27 | #include "platform.h" | ||
28 | #if HAVE_LIBIDN2 | ||
29 | #if HAVE_IDN2_H | ||
30 | #include <idn2.h> | ||
31 | #elif HAVE_IDN2_IDN2_H | ||
32 | #include <idn2/idn2.h> | ||
33 | #endif | ||
34 | #elif HAVE_LIBIDN | ||
35 | #if HAVE_IDNA_H | ||
36 | #include <idna.h> | ||
37 | #elif HAVE_IDN_IDNA_H | ||
38 | #include <idn/idna.h> | ||
39 | #endif | ||
40 | #endif | ||
41 | #include "gnunet_util_lib.h" | ||
42 | |||
43 | |||
44 | /** | ||
45 | * Check if a label in UTF-8 format can be coded into valid IDNA. | ||
46 | * This can fail if the ASCII-conversion becomes longer than 63 characters. | ||
47 | * | ||
48 | * @param label label to check (UTF-8 string) | ||
49 | * @return #GNUNET_OK if the label can be converted to IDNA, | ||
50 | * #GNUNET_SYSERR if the label is not valid for DNS names | ||
51 | */ | ||
52 | int | ||
53 | GNUNET_DNSPARSER_check_label (const char *label) | ||
54 | { | ||
55 | char *output; | ||
56 | size_t slen; | ||
57 | |||
58 | if (NULL != strchr (label, '.')) | ||
59 | return GNUNET_SYSERR; /* not a label! Did you mean GNUNET_DNSPARSER_check_name? */ | ||
60 | if (0 == strcmp (label, "@")) /* '@' is reserved for the empty label, see #GNUNET_GNS_EMPTY_LABEL_AT */ | ||
61 | return GNUNET_SYSERR; | ||
62 | if (IDNA_SUCCESS != idna_to_ascii_8z (label, &output, IDNA_ALLOW_UNASSIGNED)) | ||
63 | return GNUNET_SYSERR; | ||
64 | slen = strlen (output); | ||
65 | free (output); | ||
66 | return (slen > 63) ? GNUNET_SYSERR : GNUNET_OK; | ||
67 | } | ||
68 | |||
69 | |||
70 | /** | ||
71 | * Check if a label in UTF-8 format can be coded into valid IDNA. | ||
72 | * This can fail if the ASCII-conversion becomes longer than 253 characters. | ||
73 | * | ||
74 | * @param name name to check (UTF-8 string) | ||
75 | * @return #GNUNET_OK if the label can be converted to IDNA, | ||
76 | * #GNUNET_SYSERR if the label is not valid for DNS names | ||
77 | */ | ||
78 | int | ||
79 | GNUNET_DNSPARSER_check_name (const char *name) | ||
80 | { | ||
81 | char *ldup; | ||
82 | char *output; | ||
83 | size_t slen; | ||
84 | char *tok; | ||
85 | |||
86 | ldup = GNUNET_strdup (name); | ||
87 | for (tok = strtok (ldup, "."); NULL != tok; tok = strtok (NULL, ".")) | ||
88 | if (GNUNET_OK != GNUNET_DNSPARSER_check_label (tok)) | ||
89 | { | ||
90 | GNUNET_free (ldup); | ||
91 | return GNUNET_SYSERR; | ||
92 | } | ||
93 | GNUNET_free (ldup); | ||
94 | if (IDNA_SUCCESS != idna_to_ascii_8z (name, &output, IDNA_ALLOW_UNASSIGNED)) | ||
95 | return GNUNET_SYSERR; | ||
96 | slen = strlen (output); | ||
97 | free (output); | ||
98 | return (slen > 253) ? GNUNET_SYSERR : GNUNET_OK; | ||
99 | } | ||
100 | |||
101 | |||
102 | /** | ||
103 | * Free SOA information record. | ||
104 | * | ||
105 | * @param soa record to free | ||
106 | */ | ||
107 | void | ||
108 | GNUNET_DNSPARSER_free_soa (struct GNUNET_DNSPARSER_SoaRecord *soa) | ||
109 | { | ||
110 | if (NULL == soa) | ||
111 | return; | ||
112 | GNUNET_free (soa->mname); | ||
113 | GNUNET_free (soa->rname); | ||
114 | GNUNET_free (soa); | ||
115 | } | ||
116 | |||
117 | |||
118 | /** | ||
119 | * Free CERT information record. | ||
120 | * | ||
121 | * @param cert record to free | ||
122 | */ | ||
123 | void | ||
124 | GNUNET_DNSPARSER_free_cert (struct GNUNET_DNSPARSER_CertRecord *cert) | ||
125 | { | ||
126 | if (NULL == cert) | ||
127 | return; | ||
128 | GNUNET_free (cert->certificate_data); | ||
129 | GNUNET_free (cert); | ||
130 | } | ||
131 | |||
132 | |||
133 | /** | ||
134 | * Free SRV information record. | ||
135 | * | ||
136 | * @param srv record to free | ||
137 | */ | ||
138 | void | ||
139 | GNUNET_DNSPARSER_free_srv (struct GNUNET_DNSPARSER_SrvRecord *srv) | ||
140 | { | ||
141 | if (NULL == srv) | ||
142 | return; | ||
143 | GNUNET_free (srv->target); | ||
144 | GNUNET_free (srv); | ||
145 | } | ||
146 | |||
147 | |||
148 | /** | ||
149 | * Free MX information record. | ||
150 | * | ||
151 | * @param mx record to free | ||
152 | */ | ||
153 | void | ||
154 | GNUNET_DNSPARSER_free_mx (struct GNUNET_DNSPARSER_MxRecord *mx) | ||
155 | { | ||
156 | if (NULL == mx) | ||
157 | return; | ||
158 | GNUNET_free (mx->mxhost); | ||
159 | GNUNET_free (mx); | ||
160 | } | ||
161 | |||
162 | |||
163 | /** | ||
164 | * Free the given DNS record. | ||
165 | * | ||
166 | * @param r record to free | ||
167 | */ | ||
168 | void | ||
169 | GNUNET_DNSPARSER_free_record (struct GNUNET_DNSPARSER_Record *r) | ||
170 | { | ||
171 | GNUNET_free (r->name); | ||
172 | switch (r->type) | ||
173 | { | ||
174 | case GNUNET_DNSPARSER_TYPE_MX: | ||
175 | GNUNET_DNSPARSER_free_mx (r->data.mx); | ||
176 | break; | ||
177 | |||
178 | case GNUNET_DNSPARSER_TYPE_SOA: | ||
179 | GNUNET_DNSPARSER_free_soa (r->data.soa); | ||
180 | break; | ||
181 | |||
182 | case GNUNET_DNSPARSER_TYPE_SRV: | ||
183 | GNUNET_DNSPARSER_free_srv (r->data.srv); | ||
184 | break; | ||
185 | |||
186 | case GNUNET_DNSPARSER_TYPE_CERT: | ||
187 | GNUNET_DNSPARSER_free_cert (r->data.cert); | ||
188 | break; | ||
189 | |||
190 | case GNUNET_DNSPARSER_TYPE_NS: | ||
191 | case GNUNET_DNSPARSER_TYPE_CNAME: | ||
192 | case GNUNET_DNSPARSER_TYPE_PTR: | ||
193 | GNUNET_free (r->data.hostname); | ||
194 | break; | ||
195 | |||
196 | default: | ||
197 | GNUNET_free (r->data.raw.data); | ||
198 | break; | ||
199 | } | ||
200 | } | ||
201 | |||
202 | |||
203 | /** | ||
204 | * Parse name inside of a DNS query or record. | ||
205 | * | ||
206 | * @param udp_payload entire UDP payload | ||
207 | * @param udp_payload_length length of @a udp_payload | ||
208 | * @param off pointer to the offset of the name to parse in the udp_payload (to be | ||
209 | * incremented by the size of the name) | ||
210 | * @param depth current depth of our recursion (to prevent stack overflow) | ||
211 | * @return name as 0-terminated C string on success, NULL if the payload is malformed | ||
212 | */ | ||
213 | static char * | ||
214 | parse_name (const char *udp_payload, | ||
215 | size_t udp_payload_length, | ||
216 | size_t *off, | ||
217 | unsigned int depth) | ||
218 | { | ||
219 | const uint8_t *input = (const uint8_t *) udp_payload; | ||
220 | char *ret; | ||
221 | char *tmp; | ||
222 | char *xstr; | ||
223 | uint8_t len; | ||
224 | size_t xoff; | ||
225 | char *utf8; | ||
226 | Idna_rc rc; | ||
227 | |||
228 | ret = GNUNET_strdup (""); | ||
229 | while (1) | ||
230 | { | ||
231 | if (*off >= udp_payload_length) | ||
232 | { | ||
233 | GNUNET_break_op (0); | ||
234 | goto error; | ||
235 | } | ||
236 | len = input[*off]; | ||
237 | if (0 == len) | ||
238 | { | ||
239 | (*off)++; | ||
240 | break; | ||
241 | } | ||
242 | if (len < 64) | ||
243 | { | ||
244 | if (*off + 1 + len > udp_payload_length) | ||
245 | { | ||
246 | GNUNET_break_op (0); | ||
247 | goto error; | ||
248 | } | ||
249 | GNUNET_asprintf (&tmp, "%.*s", (int) len, &udp_payload[*off + 1]); | ||
250 | if (IDNA_SUCCESS != | ||
251 | (rc = idna_to_unicode_8z8z (tmp, &utf8, IDNA_ALLOW_UNASSIGNED))) | ||
252 | { | ||
253 | GNUNET_log (GNUNET_ERROR_TYPE_INFO, | ||
254 | _ ("Failed to convert DNS IDNA name `%s' to UTF-8: %s\n"), | ||
255 | tmp, | ||
256 | idna_strerror (rc)); | ||
257 | GNUNET_free (tmp); | ||
258 | GNUNET_asprintf (&tmp, | ||
259 | "%s%.*s.", | ||
260 | ret, | ||
261 | (int) len, | ||
262 | &udp_payload[*off + 1]); | ||
263 | } | ||
264 | else | ||
265 | { | ||
266 | GNUNET_free (tmp); | ||
267 | GNUNET_asprintf (&tmp, "%s%s.", ret, utf8); | ||
268 | free (utf8); | ||
269 | } | ||
270 | GNUNET_free (ret); | ||
271 | ret = tmp; | ||
272 | *off += 1 + len; | ||
273 | } | ||
274 | else if ((64 | 128) == (len & (64 | 128))) | ||
275 | { | ||
276 | if (depth > 32) | ||
277 | { | ||
278 | GNUNET_break_op (0); | ||
279 | goto error; /* hard bound on stack to prevent "infinite" recursion, disallow! */ | ||
280 | } | ||
281 | /* pointer to string */ | ||
282 | if (*off + 1 > udp_payload_length) | ||
283 | { | ||
284 | GNUNET_break_op (0); | ||
285 | goto error; | ||
286 | } | ||
287 | xoff = ((len - (64 | 128)) << 8) + input[*off + 1]; | ||
288 | xstr = parse_name (udp_payload, udp_payload_length, &xoff, depth + 1); | ||
289 | if (NULL == xstr) | ||
290 | { | ||
291 | GNUNET_break_op (0); | ||
292 | goto error; | ||
293 | } | ||
294 | GNUNET_asprintf (&tmp, "%s%s.", ret, xstr); | ||
295 | GNUNET_free (ret); | ||
296 | GNUNET_free (xstr); | ||
297 | ret = tmp; | ||
298 | if (strlen (ret) > udp_payload_length) | ||
299 | { | ||
300 | GNUNET_break_op (0); | ||
301 | goto error; /* we are looping (building an infinite string) */ | ||
302 | } | ||
303 | *off += 2; | ||
304 | /* pointers always terminate names */ | ||
305 | break; | ||
306 | } | ||
307 | else | ||
308 | { | ||
309 | /* neither pointer nor inline string, not supported... */ | ||
310 | GNUNET_break_op (0); | ||
311 | goto error; | ||
312 | } | ||
313 | } | ||
314 | if (0 < strlen (ret)) | ||
315 | ret[strlen (ret) - 1] = '\0'; /* eat tailing '.' */ | ||
316 | return ret; | ||
317 | error: | ||
318 | GNUNET_break_op (0); | ||
319 | GNUNET_free (ret); | ||
320 | return NULL; | ||
321 | } | ||
322 | |||
323 | |||
324 | /** | ||
325 | * Parse name inside of a DNS query or record. | ||
326 | * | ||
327 | * @param udp_payload entire UDP payload | ||
328 | * @param udp_payload_length length of @a udp_payload | ||
329 | * @param off pointer to the offset of the name to parse in the udp_payload (to be | ||
330 | * incremented by the size of the name) | ||
331 | * @return name as 0-terminated C string on success, NULL if the payload is malformed | ||
332 | */ | ||
333 | char * | ||
334 | GNUNET_DNSPARSER_parse_name (const char *udp_payload, | ||
335 | size_t udp_payload_length, | ||
336 | size_t *off) | ||
337 | { | ||
338 | return parse_name (udp_payload, udp_payload_length, off, 0); | ||
339 | } | ||
340 | |||
341 | |||
342 | /** | ||
343 | * Parse a DNS query entry. | ||
344 | * | ||
345 | * @param udp_payload entire UDP payload | ||
346 | * @param udp_payload_length length of @a udp_payload | ||
347 | * @param off pointer to the offset of the query to parse in the udp_payload (to be | ||
348 | * incremented by the size of the query) | ||
349 | * @param q where to write the query information | ||
350 | * @return #GNUNET_OK on success, #GNUNET_SYSERR if the query is malformed | ||
351 | */ | ||
352 | int | ||
353 | GNUNET_DNSPARSER_parse_query (const char *udp_payload, | ||
354 | size_t udp_payload_length, | ||
355 | size_t *off, | ||
356 | struct GNUNET_DNSPARSER_Query *q) | ||
357 | { | ||
358 | char *name; | ||
359 | struct GNUNET_TUN_DnsQueryLine ql; | ||
360 | |||
361 | name = GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
362 | if (NULL == name) | ||
363 | { | ||
364 | GNUNET_break_op (0); | ||
365 | return GNUNET_SYSERR; | ||
366 | } | ||
367 | q->name = name; | ||
368 | if (*off + sizeof(struct GNUNET_TUN_DnsQueryLine) > udp_payload_length) | ||
369 | { | ||
370 | GNUNET_break_op (0); | ||
371 | return GNUNET_SYSERR; | ||
372 | } | ||
373 | GNUNET_memcpy (&ql, &udp_payload[*off], sizeof(ql)); | ||
374 | *off += sizeof(ql); | ||
375 | q->type = ntohs (ql.type); | ||
376 | q->dns_traffic_class = ntohs (ql.dns_traffic_class); | ||
377 | return GNUNET_OK; | ||
378 | } | ||
379 | |||
380 | |||
381 | /** | ||
382 | * Parse a DNS SOA record. | ||
383 | * | ||
384 | * @param udp_payload reference to UDP packet | ||
385 | * @param udp_payload_length length of @a udp_payload | ||
386 | * @param off pointer to the offset of the query to parse in the SOA record (to be | ||
387 | * incremented by the size of the record), unchanged on error | ||
388 | * @return the parsed SOA record, NULL on error | ||
389 | */ | ||
390 | struct GNUNET_DNSPARSER_SoaRecord * | ||
391 | GNUNET_DNSPARSER_parse_soa (const char *udp_payload, | ||
392 | size_t udp_payload_length, | ||
393 | size_t *off) | ||
394 | { | ||
395 | struct GNUNET_DNSPARSER_SoaRecord *soa; | ||
396 | struct GNUNET_TUN_DnsSoaRecord soa_bin; | ||
397 | size_t old_off; | ||
398 | |||
399 | old_off = *off; | ||
400 | soa = GNUNET_new (struct GNUNET_DNSPARSER_SoaRecord); | ||
401 | soa->mname = | ||
402 | GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
403 | soa->rname = | ||
404 | GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
405 | if ((NULL == soa->mname) || (NULL == soa->rname) || | ||
406 | (*off + sizeof(struct GNUNET_TUN_DnsSoaRecord) > udp_payload_length)) | ||
407 | { | ||
408 | GNUNET_break_op (0); | ||
409 | GNUNET_DNSPARSER_free_soa (soa); | ||
410 | *off = old_off; | ||
411 | return NULL; | ||
412 | } | ||
413 | GNUNET_memcpy (&soa_bin, | ||
414 | &udp_payload[*off], | ||
415 | sizeof(struct GNUNET_TUN_DnsSoaRecord)); | ||
416 | soa->serial = ntohl (soa_bin.serial); | ||
417 | soa->refresh = ntohl (soa_bin.refresh); | ||
418 | soa->retry = ntohl (soa_bin.retry); | ||
419 | soa->expire = ntohl (soa_bin.expire); | ||
420 | soa->minimum_ttl = ntohl (soa_bin.minimum); | ||
421 | (*off) += sizeof(struct GNUNET_TUN_DnsSoaRecord); | ||
422 | return soa; | ||
423 | } | ||
424 | |||
425 | |||
426 | /** | ||
427 | * Parse a DNS MX record. | ||
428 | * | ||
429 | * @param udp_payload reference to UDP packet | ||
430 | * @param udp_payload_length length of @a udp_payload | ||
431 | * @param off pointer to the offset of the query to parse in the MX record (to be | ||
432 | * incremented by the size of the record), unchanged on error | ||
433 | * @return the parsed MX record, NULL on error | ||
434 | */ | ||
435 | struct GNUNET_DNSPARSER_MxRecord * | ||
436 | GNUNET_DNSPARSER_parse_mx (const char *udp_payload, | ||
437 | size_t udp_payload_length, | ||
438 | size_t *off) | ||
439 | { | ||
440 | struct GNUNET_DNSPARSER_MxRecord *mx; | ||
441 | uint16_t mxpref; | ||
442 | size_t old_off; | ||
443 | |||
444 | old_off = *off; | ||
445 | if (*off + sizeof(uint16_t) > udp_payload_length) | ||
446 | { | ||
447 | GNUNET_break_op (0); | ||
448 | return NULL; | ||
449 | } | ||
450 | GNUNET_memcpy (&mxpref, &udp_payload[*off], sizeof(uint16_t)); | ||
451 | (*off) += sizeof(uint16_t); | ||
452 | mx = GNUNET_new (struct GNUNET_DNSPARSER_MxRecord); | ||
453 | mx->preference = ntohs (mxpref); | ||
454 | mx->mxhost = | ||
455 | GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
456 | if (NULL == mx->mxhost) | ||
457 | { | ||
458 | GNUNET_break_op (0); | ||
459 | GNUNET_DNSPARSER_free_mx (mx); | ||
460 | *off = old_off; | ||
461 | return NULL; | ||
462 | } | ||
463 | return mx; | ||
464 | } | ||
465 | |||
466 | |||
467 | /** | ||
468 | * Parse a DNS SRV record. | ||
469 | * | ||
470 | * @param udp_payload reference to UDP packet | ||
471 | * @param udp_payload_length length of @a udp_payload | ||
472 | * @param off pointer to the offset of the query to parse in the SRV record (to be | ||
473 | * incremented by the size of the record), unchanged on error | ||
474 | * @return the parsed SRV record, NULL on error | ||
475 | */ | ||
476 | struct GNUNET_DNSPARSER_SrvRecord * | ||
477 | GNUNET_DNSPARSER_parse_srv (const char *udp_payload, | ||
478 | size_t udp_payload_length, | ||
479 | size_t *off) | ||
480 | { | ||
481 | struct GNUNET_DNSPARSER_SrvRecord *srv; | ||
482 | struct GNUNET_TUN_DnsSrvRecord srv_bin; | ||
483 | size_t old_off; | ||
484 | |||
485 | old_off = *off; | ||
486 | if (*off + sizeof(struct GNUNET_TUN_DnsSrvRecord) > udp_payload_length) | ||
487 | return NULL; | ||
488 | GNUNET_memcpy (&srv_bin, | ||
489 | &udp_payload[*off], | ||
490 | sizeof(struct GNUNET_TUN_DnsSrvRecord)); | ||
491 | (*off) += sizeof(struct GNUNET_TUN_DnsSrvRecord); | ||
492 | srv = GNUNET_new (struct GNUNET_DNSPARSER_SrvRecord); | ||
493 | srv->priority = ntohs (srv_bin.prio); | ||
494 | srv->weight = ntohs (srv_bin.weight); | ||
495 | srv->port = ntohs (srv_bin.port); | ||
496 | srv->target = | ||
497 | GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
498 | if (NULL == srv->target) | ||
499 | { | ||
500 | GNUNET_DNSPARSER_free_srv (srv); | ||
501 | *off = old_off; | ||
502 | return NULL; | ||
503 | } | ||
504 | return srv; | ||
505 | } | ||
506 | |||
507 | |||
508 | /** | ||
509 | * Parse a DNS CERT record. | ||
510 | * | ||
511 | * @param udp_payload reference to UDP packet | ||
512 | * @param udp_payload_length length of @a udp_payload | ||
513 | * @param off pointer to the offset of the query to parse in the CERT record (to be | ||
514 | * incremented by the size of the record), unchanged on error | ||
515 | * @return the parsed CERT record, NULL on error | ||
516 | */ | ||
517 | struct GNUNET_DNSPARSER_CertRecord * | ||
518 | GNUNET_DNSPARSER_parse_cert (const char *udp_payload, | ||
519 | size_t udp_payload_length, | ||
520 | size_t *off) | ||
521 | { | ||
522 | struct GNUNET_DNSPARSER_CertRecord *cert; | ||
523 | struct GNUNET_TUN_DnsCertRecord dcert; | ||
524 | |||
525 | if (*off + sizeof(struct GNUNET_TUN_DnsCertRecord) >= udp_payload_length) | ||
526 | { | ||
527 | GNUNET_break_op (0); | ||
528 | return NULL; | ||
529 | } | ||
530 | GNUNET_memcpy (&dcert, | ||
531 | &udp_payload[*off], | ||
532 | sizeof(struct GNUNET_TUN_DnsCertRecord)); | ||
533 | (*off) += sizeof(struct GNUNET_TUN_DnsCertRecord); | ||
534 | cert = GNUNET_new (struct GNUNET_DNSPARSER_CertRecord); | ||
535 | cert->cert_type = ntohs (dcert.cert_type); | ||
536 | cert->cert_tag = ntohs (dcert.cert_tag); | ||
537 | cert->algorithm = dcert.algorithm; | ||
538 | cert->certificate_size = udp_payload_length - (*off); | ||
539 | cert->certificate_data = GNUNET_malloc (cert->certificate_size); | ||
540 | GNUNET_memcpy (cert->certificate_data, | ||
541 | &udp_payload[*off], | ||
542 | cert->certificate_size); | ||
543 | (*off) += cert->certificate_size; | ||
544 | return cert; | ||
545 | } | ||
546 | |||
547 | |||
548 | /** | ||
549 | * Parse a DNS record entry. | ||
550 | * | ||
551 | * @param udp_payload entire UDP payload | ||
552 | * @param udp_payload_length length of @a udp_payload | ||
553 | * @param off pointer to the offset of the record to parse in the udp_payload (to be | ||
554 | * incremented by the size of the record) | ||
555 | * @param r where to write the record information | ||
556 | * @return #GNUNET_OK on success, #GNUNET_SYSERR if the record is malformed | ||
557 | */ | ||
558 | int | ||
559 | GNUNET_DNSPARSER_parse_record (const char *udp_payload, | ||
560 | size_t udp_payload_length, | ||
561 | size_t *off, | ||
562 | struct GNUNET_DNSPARSER_Record *r) | ||
563 | { | ||
564 | char *name; | ||
565 | struct GNUNET_TUN_DnsRecordLine rl; | ||
566 | size_t old_off; | ||
567 | uint16_t data_len; | ||
568 | |||
569 | name = GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
570 | if (NULL == name) | ||
571 | { | ||
572 | GNUNET_break_op (0); | ||
573 | return GNUNET_SYSERR; | ||
574 | } | ||
575 | r->name = name; | ||
576 | if (*off + sizeof(struct GNUNET_TUN_DnsRecordLine) > udp_payload_length) | ||
577 | { | ||
578 | GNUNET_break_op (0); | ||
579 | return GNUNET_SYSERR; | ||
580 | } | ||
581 | GNUNET_memcpy (&rl, &udp_payload[*off], sizeof(rl)); | ||
582 | (*off) += sizeof(rl); | ||
583 | r->type = ntohs (rl.type); | ||
584 | r->dns_traffic_class = ntohs (rl.dns_traffic_class); | ||
585 | r->expiration_time = GNUNET_TIME_relative_to_absolute ( | ||
586 | GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, ntohl (rl.ttl))); | ||
587 | data_len = ntohs (rl.data_len); | ||
588 | if (*off + data_len > udp_payload_length) | ||
589 | { | ||
590 | GNUNET_break_op (0); | ||
591 | return GNUNET_SYSERR; | ||
592 | } | ||
593 | old_off = *off; | ||
594 | switch (r->type) | ||
595 | { | ||
596 | case GNUNET_DNSPARSER_TYPE_NS: | ||
597 | case GNUNET_DNSPARSER_TYPE_CNAME: | ||
598 | case GNUNET_DNSPARSER_TYPE_DNAME: | ||
599 | case GNUNET_DNSPARSER_TYPE_PTR: | ||
600 | r->data.hostname = | ||
601 | GNUNET_DNSPARSER_parse_name (udp_payload, udp_payload_length, off); | ||
602 | if ((NULL == r->data.hostname) || (old_off + data_len != *off)) | ||
603 | return GNUNET_SYSERR; | ||
604 | return GNUNET_OK; | ||
605 | |||
606 | case GNUNET_DNSPARSER_TYPE_SOA: | ||
607 | r->data.soa = | ||
608 | GNUNET_DNSPARSER_parse_soa (udp_payload, udp_payload_length, off); | ||
609 | if ((NULL == r->data.soa) || (old_off + data_len != *off)) | ||
610 | { | ||
611 | GNUNET_break_op (0); | ||
612 | return GNUNET_SYSERR; | ||
613 | } | ||
614 | return GNUNET_OK; | ||
615 | |||
616 | case GNUNET_DNSPARSER_TYPE_MX: | ||
617 | r->data.mx = | ||
618 | GNUNET_DNSPARSER_parse_mx (udp_payload, udp_payload_length, off); | ||
619 | if ((NULL == r->data.mx) || (old_off + data_len != *off)) | ||
620 | { | ||
621 | GNUNET_break_op (0); | ||
622 | return GNUNET_SYSERR; | ||
623 | } | ||
624 | return GNUNET_OK; | ||
625 | |||
626 | case GNUNET_DNSPARSER_TYPE_SRV: | ||
627 | r->data.srv = | ||
628 | GNUNET_DNSPARSER_parse_srv (udp_payload, udp_payload_length, off); | ||
629 | if ((NULL == r->data.srv) || (old_off + data_len != *off)) | ||
630 | { | ||
631 | GNUNET_break_op (0); | ||
632 | return GNUNET_SYSERR; | ||
633 | } | ||
634 | return GNUNET_OK; | ||
635 | |||
636 | default: | ||
637 | r->data.raw.data = GNUNET_malloc (data_len); | ||
638 | r->data.raw.data_len = data_len; | ||
639 | GNUNET_memcpy (r->data.raw.data, &udp_payload[*off], data_len); | ||
640 | break; | ||
641 | } | ||
642 | (*off) += data_len; | ||
643 | return GNUNET_OK; | ||
644 | } | ||
645 | |||
646 | |||
647 | /** | ||
648 | * Parse a UDP payload of a DNS packet in to a nice struct for further | ||
649 | * processing and manipulation. | ||
650 | * | ||
651 | * @param udp_payload wire-format of the DNS packet | ||
652 | * @param udp_payload_length number of bytes in @a udp_payload | ||
653 | * @return NULL on error, otherwise the parsed packet | ||
654 | */ | ||
655 | struct GNUNET_DNSPARSER_Packet * | ||
656 | GNUNET_DNSPARSER_parse (const char *udp_payload, size_t udp_payload_length) | ||
657 | { | ||
658 | struct GNUNET_DNSPARSER_Packet *p; | ||
659 | const struct GNUNET_TUN_DnsHeader *dns; | ||
660 | size_t off; | ||
661 | unsigned int n; | ||
662 | |||
663 | if (udp_payload_length < sizeof(struct GNUNET_TUN_DnsHeader)) | ||
664 | return NULL; | ||
665 | dns = (const struct GNUNET_TUN_DnsHeader *) udp_payload; | ||
666 | off = sizeof(struct GNUNET_TUN_DnsHeader); | ||
667 | p = GNUNET_new (struct GNUNET_DNSPARSER_Packet); | ||
668 | p->flags = dns->flags; | ||
669 | p->id = dns->id; | ||
670 | n = ntohs (dns->query_count); | ||
671 | if (n > 0) | ||
672 | { | ||
673 | p->queries = GNUNET_new_array (n, struct GNUNET_DNSPARSER_Query); | ||
674 | p->num_queries = n; | ||
675 | for (unsigned int i = 0; i < n; i++) | ||
676 | if (GNUNET_OK != GNUNET_DNSPARSER_parse_query (udp_payload, | ||
677 | udp_payload_length, | ||
678 | &off, | ||
679 | &p->queries[i])) | ||
680 | goto error; | ||
681 | } | ||
682 | n = ntohs (dns->answer_rcount); | ||
683 | if (n > 0) | ||
684 | { | ||
685 | p->answers = GNUNET_new_array (n, struct GNUNET_DNSPARSER_Record); | ||
686 | p->num_answers = n; | ||
687 | for (unsigned int i = 0; i < n; i++) | ||
688 | if (GNUNET_OK != GNUNET_DNSPARSER_parse_record (udp_payload, | ||
689 | udp_payload_length, | ||
690 | &off, | ||
691 | &p->answers[i])) | ||
692 | goto error; | ||
693 | } | ||
694 | n = ntohs (dns->authority_rcount); | ||
695 | if (n > 0) | ||
696 | { | ||
697 | p->authority_records = GNUNET_new_array (n, struct GNUNET_DNSPARSER_Record); | ||
698 | p->num_authority_records = n; | ||
699 | for (unsigned int i = 0; i < n; i++) | ||
700 | if (GNUNET_OK != GNUNET_DNSPARSER_parse_record (udp_payload, | ||
701 | udp_payload_length, | ||
702 | &off, | ||
703 | &p->authority_records[i])) | ||
704 | goto error; | ||
705 | } | ||
706 | n = ntohs (dns->additional_rcount); | ||
707 | if (n > 0) | ||
708 | { | ||
709 | p->additional_records = | ||
710 | GNUNET_new_array (n, struct GNUNET_DNSPARSER_Record); | ||
711 | p->num_additional_records = n; | ||
712 | for (unsigned int i = 0; i < n; i++) | ||
713 | { | ||
714 | if (GNUNET_OK != | ||
715 | GNUNET_DNSPARSER_parse_record (udp_payload, | ||
716 | udp_payload_length, | ||
717 | &off, | ||
718 | &p->additional_records[i])) | ||
719 | goto error; | ||
720 | } | ||
721 | } | ||
722 | return p; | ||
723 | error: | ||
724 | GNUNET_break_op (0); | ||
725 | GNUNET_DNSPARSER_free_packet (p); | ||
726 | return NULL; | ||
727 | } | ||
728 | |||
729 | |||
730 | /** | ||
731 | * Duplicate (deep-copy) the given DNS record | ||
732 | * | ||
733 | * @param r the record | ||
734 | * @return the newly allocated record | ||
735 | */ | ||
736 | struct GNUNET_DNSPARSER_Record * | ||
737 | GNUNET_DNSPARSER_duplicate_record (const struct GNUNET_DNSPARSER_Record *r) | ||
738 | { | ||
739 | struct GNUNET_DNSPARSER_Record *dup = GNUNET_memdup (r, sizeof(*r)); | ||
740 | |||
741 | dup->name = GNUNET_strdup (r->name); | ||
742 | switch (r->type) | ||
743 | { | ||
744 | case GNUNET_DNSPARSER_TYPE_NS: | ||
745 | case GNUNET_DNSPARSER_TYPE_CNAME: | ||
746 | case GNUNET_DNSPARSER_TYPE_PTR: { | ||
747 | dup->data.hostname = GNUNET_strdup (r->data.hostname); | ||
748 | break; | ||
749 | } | ||
750 | |||
751 | case GNUNET_DNSPARSER_TYPE_SOA: { | ||
752 | dup->data.soa = GNUNET_DNSPARSER_duplicate_soa_record (r->data.soa); | ||
753 | break; | ||
754 | } | ||
755 | |||
756 | case GNUNET_DNSPARSER_TYPE_CERT: { | ||
757 | dup->data.cert = GNUNET_DNSPARSER_duplicate_cert_record (r->data.cert); | ||
758 | break; | ||
759 | } | ||
760 | |||
761 | case GNUNET_DNSPARSER_TYPE_MX: { | ||
762 | dup->data.mx = GNUNET_DNSPARSER_duplicate_mx_record (r->data.mx); | ||
763 | break; | ||
764 | } | ||
765 | |||
766 | case GNUNET_DNSPARSER_TYPE_SRV: { | ||
767 | dup->data.srv = GNUNET_DNSPARSER_duplicate_srv_record (r->data.srv); | ||
768 | break; | ||
769 | } | ||
770 | |||
771 | default: { | ||
772 | dup->data.raw.data = GNUNET_memdup (r->data.raw.data, | ||
773 | r->data.raw.data_len); | ||
774 | } | ||
775 | } | ||
776 | return dup; | ||
777 | } | ||
778 | |||
779 | |||
780 | /** | ||
781 | * Duplicate (deep-copy) the given DNS record | ||
782 | * | ||
783 | * @param r the record | ||
784 | * @return the newly allocated record | ||
785 | */ | ||
786 | struct GNUNET_DNSPARSER_SoaRecord * | ||
787 | GNUNET_DNSPARSER_duplicate_soa_record ( | ||
788 | const struct GNUNET_DNSPARSER_SoaRecord *r) | ||
789 | { | ||
790 | struct GNUNET_DNSPARSER_SoaRecord *dup = GNUNET_memdup (r, sizeof(*r)); | ||
791 | |||
792 | dup->mname = GNUNET_strdup (r->mname); | ||
793 | dup->rname = GNUNET_strdup (r->rname); | ||
794 | return dup; | ||
795 | } | ||
796 | |||
797 | |||
798 | /** | ||
799 | * Duplicate (deep-copy) the given DNS record | ||
800 | * | ||
801 | * @param r the record | ||
802 | * @return the newly allocated record | ||
803 | */ | ||
804 | struct GNUNET_DNSPARSER_CertRecord * | ||
805 | GNUNET_DNSPARSER_duplicate_cert_record ( | ||
806 | const struct GNUNET_DNSPARSER_CertRecord *r) | ||
807 | { | ||
808 | struct GNUNET_DNSPARSER_CertRecord *dup = GNUNET_memdup (r, sizeof(*r)); | ||
809 | |||
810 | dup->certificate_data = GNUNET_strdup (r->certificate_data); | ||
811 | return dup; | ||
812 | } | ||
813 | |||
814 | |||
815 | /** | ||
816 | * Duplicate (deep-copy) the given DNS record | ||
817 | * | ||
818 | * @param r the record | ||
819 | * @return the newly allocated record | ||
820 | */ | ||
821 | struct GNUNET_DNSPARSER_MxRecord * | ||
822 | GNUNET_DNSPARSER_duplicate_mx_record (const struct GNUNET_DNSPARSER_MxRecord *r) | ||
823 | { | ||
824 | struct GNUNET_DNSPARSER_MxRecord *dup = GNUNET_memdup (r, sizeof(*r)); | ||
825 | |||
826 | dup->mxhost = GNUNET_strdup (r->mxhost); | ||
827 | return dup; | ||
828 | } | ||
829 | |||
830 | |||
831 | /** | ||
832 | * Duplicate (deep-copy) the given DNS record | ||
833 | * | ||
834 | * @param r the record | ||
835 | * @return the newly allocated record | ||
836 | */ | ||
837 | struct GNUNET_DNSPARSER_SrvRecord * | ||
838 | GNUNET_DNSPARSER_duplicate_srv_record ( | ||
839 | const struct GNUNET_DNSPARSER_SrvRecord *r) | ||
840 | { | ||
841 | struct GNUNET_DNSPARSER_SrvRecord *dup = GNUNET_memdup (r, sizeof(*r)); | ||
842 | |||
843 | dup->target = GNUNET_strdup (r->target); | ||
844 | return dup; | ||
845 | } | ||
846 | |||
847 | |||
848 | /** | ||
849 | * Free memory taken by a packet. | ||
850 | * | ||
851 | * @param p packet to free | ||
852 | */ | ||
853 | void | ||
854 | GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p) | ||
855 | { | ||
856 | for (unsigned int i = 0; i < p->num_queries; i++) | ||
857 | GNUNET_free (p->queries[i].name); | ||
858 | GNUNET_free (p->queries); | ||
859 | for (unsigned int i = 0; i < p->num_answers; i++) | ||
860 | GNUNET_DNSPARSER_free_record (&p->answers[i]); | ||
861 | GNUNET_free (p->answers); | ||
862 | for (unsigned int i = 0; i < p->num_authority_records; i++) | ||
863 | GNUNET_DNSPARSER_free_record (&p->authority_records[i]); | ||
864 | GNUNET_free (p->authority_records); | ||
865 | for (unsigned int i = 0; i < p->num_additional_records; i++) | ||
866 | GNUNET_DNSPARSER_free_record (&p->additional_records[i]); | ||
867 | GNUNET_free (p->additional_records); | ||
868 | GNUNET_free (p); | ||
869 | } | ||
870 | |||
871 | |||
872 | /* ********************** DNS packet assembly code **************** */ | ||
873 | |||
874 | |||
875 | /** | ||
876 | * Add a DNS name to the UDP packet at the given location, converting | ||
877 | * the name to IDNA notation as necessary. | ||
878 | * | ||
879 | * @param dst where to write the name (UDP packet) | ||
880 | * @param dst_len number of bytes in @a dst | ||
881 | * @param off pointer to offset where to write the name (increment by bytes used) | ||
882 | * must not be changed if there is an error | ||
883 | * @param name name to write | ||
884 | * @return #GNUNET_SYSERR if @a name is invalid | ||
885 | * #GNUNET_NO if @a name did not fit | ||
886 | * #GNUNET_OK if @a name was added to @a dst | ||
887 | */ | ||
888 | int | ||
889 | GNUNET_DNSPARSER_builder_add_name (char *dst, | ||
890 | size_t dst_len, | ||
891 | size_t *off, | ||
892 | const char *name) | ||
893 | { | ||
894 | const char *dot; | ||
895 | const char *idna_name; | ||
896 | char *idna_start; | ||
897 | size_t start; | ||
898 | size_t pos; | ||
899 | size_t len; | ||
900 | Idna_rc rc; | ||
901 | |||
902 | if (NULL == name) | ||
903 | return GNUNET_SYSERR; | ||
904 | |||
905 | if (IDNA_SUCCESS != | ||
906 | (rc = idna_to_ascii_8z (name, &idna_start, IDNA_ALLOW_UNASSIGNED))) | ||
907 | { | ||
908 | GNUNET_log (GNUNET_ERROR_TYPE_WARNING, | ||
909 | _ ( | ||
910 | "Failed to convert UTF-8 name `%s' to DNS IDNA format: %s\n"), | ||
911 | name, | ||
912 | idna_strerror (rc)); | ||
913 | return GNUNET_NO; | ||
914 | } | ||
915 | idna_name = idna_start; | ||
916 | start = *off; | ||
917 | if (start + strlen (idna_name) + 2 > dst_len) | ||
918 | goto fail; | ||
919 | pos = start; | ||
920 | do | ||
921 | { | ||
922 | dot = strchr (idna_name, '.'); | ||
923 | if (NULL == dot) | ||
924 | len = strlen (idna_name); | ||
925 | else | ||
926 | len = dot - idna_name; | ||
927 | if ((len >= 64) || (0 == len)) | ||
928 | { | ||
929 | GNUNET_log (GNUNET_ERROR_TYPE_ERROR, | ||
930 | "Invalid DNS name `%s': label with %u characters encountered\n", | ||
931 | name, | ||
932 | (unsigned int) len); | ||
933 | goto fail; /* label too long or empty */ | ||
934 | } | ||
935 | dst[pos++] = (char) (uint8_t) len; | ||
936 | GNUNET_memcpy (&dst[pos], idna_name, len); | ||
937 | pos += len; | ||
938 | idna_name += len + 1; /* also skip dot */ | ||
939 | } | ||
940 | while (NULL != dot); | ||
941 | dst[pos++] = '\0'; /* terminator */ | ||
942 | *off = pos; | ||
943 | free (idna_start); | ||
944 | return GNUNET_OK; | ||
945 | fail: | ||
946 | free (idna_start); | ||
947 | return GNUNET_NO; | ||
948 | } | ||
949 | |||
950 | |||
951 | /** | ||
952 | * Add a DNS query to the UDP packet at the given location. | ||
953 | * | ||
954 | * @param dst where to write the query | ||
955 | * @param dst_len number of bytes in @a dst | ||
956 | * @param off pointer to offset where to write the query (increment by bytes used) | ||
957 | * must not be changed if there is an error | ||
958 | * @param query query to write | ||
959 | * @return #GNUNET_SYSERR if @a query is invalid | ||
960 | * #GNUNET_NO if @a query did not fit | ||
961 | * #GNUNET_OK if @a query was added to @a dst | ||
962 | */ | ||
963 | int | ||
964 | GNUNET_DNSPARSER_builder_add_query (char *dst, | ||
965 | size_t dst_len, | ||
966 | size_t *off, | ||
967 | const struct GNUNET_DNSPARSER_Query *query) | ||
968 | { | ||
969 | int ret; | ||
970 | struct GNUNET_TUN_DnsQueryLine ql; | ||
971 | |||
972 | ret = GNUNET_DNSPARSER_builder_add_name (dst, | ||
973 | dst_len | ||
974 | - sizeof( | ||
975 | struct GNUNET_TUN_DnsQueryLine), | ||
976 | off, | ||
977 | query->name); | ||
978 | if (ret != GNUNET_OK) | ||
979 | return ret; | ||
980 | ql.type = htons (query->type); | ||
981 | ql.dns_traffic_class = htons (query->dns_traffic_class); | ||
982 | GNUNET_memcpy (&dst[*off], &ql, sizeof(ql)); | ||
983 | (*off) += sizeof(ql); | ||
984 | return GNUNET_OK; | ||
985 | } | ||
986 | |||
987 | |||
988 | /** | ||
989 | * Add an MX record to the UDP packet at the given location. | ||
990 | * | ||
991 | * @param dst where to write the mx record | ||
992 | * @param dst_len number of bytes in @a dst | ||
993 | * @param off pointer to offset where to write the mx information (increment by bytes used); | ||
994 | * can also change if there was an error | ||
995 | * @param mx mx information to write | ||
996 | * @return #GNUNET_SYSERR if @a mx is invalid | ||
997 | * #GNUNET_NO if @a mx did not fit | ||
998 | * #GNUNET_OK if @a mx was added to @a dst | ||
999 | */ | ||
1000 | int | ||
1001 | GNUNET_DNSPARSER_builder_add_mx (char *dst, | ||
1002 | size_t dst_len, | ||
1003 | size_t *off, | ||
1004 | const struct GNUNET_DNSPARSER_MxRecord *mx) | ||
1005 | { | ||
1006 | uint16_t mxpref; | ||
1007 | |||
1008 | if (*off + sizeof(uint16_t) > dst_len) | ||
1009 | return GNUNET_NO; | ||
1010 | mxpref = htons (mx->preference); | ||
1011 | GNUNET_memcpy (&dst[*off], &mxpref, sizeof(mxpref)); | ||
1012 | (*off) += sizeof(mxpref); | ||
1013 | return GNUNET_DNSPARSER_builder_add_name (dst, dst_len, off, mx->mxhost); | ||
1014 | } | ||
1015 | |||
1016 | |||
1017 | /** | ||
1018 | * Add a CERT record to the UDP packet at the given location. | ||
1019 | * | ||
1020 | * @param dst where to write the CERT record | ||
1021 | * @param dst_len number of bytes in @a dst | ||
1022 | * @param off pointer to offset where to write the CERT information (increment by bytes used); | ||
1023 | * can also change if there was an error | ||
1024 | * @param cert CERT information to write | ||
1025 | * @return #GNUNET_SYSERR if @a cert is invalid | ||
1026 | * #GNUNET_NO if @a cert did not fit | ||
1027 | * #GNUNET_OK if @a cert was added to @a dst | ||
1028 | */ | ||
1029 | int | ||
1030 | GNUNET_DNSPARSER_builder_add_cert ( | ||
1031 | char *dst, | ||
1032 | size_t dst_len, | ||
1033 | size_t *off, | ||
1034 | const struct GNUNET_DNSPARSER_CertRecord *cert) | ||
1035 | { | ||
1036 | struct GNUNET_TUN_DnsCertRecord dcert; | ||
1037 | |||
1038 | #ifdef __clang__ | ||
1039 | #pragma clang diagnostic push | ||
1040 | #pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare" | ||
1041 | #endif | ||
1042 | if ((cert->cert_type > UINT16_MAX) || (cert->algorithm > UINT8_MAX)) | ||
1043 | { | ||
1044 | GNUNET_break (0); | ||
1045 | return GNUNET_SYSERR; | ||
1046 | } | ||
1047 | #ifdef __clang__ | ||
1048 | #pragma clang diagnostic pop | ||
1049 | #endif | ||
1050 | if (*off + sizeof(struct GNUNET_TUN_DnsCertRecord) + cert->certificate_size > | ||
1051 | dst_len) | ||
1052 | return GNUNET_NO; | ||
1053 | dcert.cert_type = htons ((uint16_t) cert->cert_type); | ||
1054 | dcert.cert_tag = htons ((uint16_t) cert->cert_tag); | ||
1055 | dcert.algorithm = (uint8_t) cert->algorithm; | ||
1056 | GNUNET_memcpy (&dst[*off], &dcert, sizeof(dcert)); | ||
1057 | (*off) += sizeof(dcert); | ||
1058 | GNUNET_memcpy (&dst[*off], cert->certificate_data, cert->certificate_size); | ||
1059 | (*off) += cert->certificate_size; | ||
1060 | return GNUNET_OK; | ||
1061 | } | ||
1062 | |||
1063 | |||
1064 | /** | ||
1065 | * Add an SOA record to the UDP packet at the given location. | ||
1066 | * | ||
1067 | * @param dst where to write the SOA record | ||
1068 | * @param dst_len number of bytes in @a dst | ||
1069 | * @param off pointer to offset where to write the SOA information (increment by bytes used) | ||
1070 | * can also change if there was an error | ||
1071 | * @param soa SOA information to write | ||
1072 | * @return #GNUNET_SYSERR if @a soa is invalid | ||
1073 | * #GNUNET_NO if @a soa did not fit | ||
1074 | * #GNUNET_OK if @a soa was added to @a dst | ||
1075 | */ | ||
1076 | int | ||
1077 | GNUNET_DNSPARSER_builder_add_soa (char *dst, | ||
1078 | size_t dst_len, | ||
1079 | size_t *off, | ||
1080 | const struct GNUNET_DNSPARSER_SoaRecord *soa) | ||
1081 | { | ||
1082 | struct GNUNET_TUN_DnsSoaRecord sd; | ||
1083 | int ret; | ||
1084 | |||
1085 | if ((GNUNET_OK != | ||
1086 | (ret = | ||
1087 | GNUNET_DNSPARSER_builder_add_name (dst, dst_len, off, soa->mname))) || | ||
1088 | (GNUNET_OK != | ||
1089 | (ret = | ||
1090 | GNUNET_DNSPARSER_builder_add_name (dst, dst_len, off, soa->rname)))) | ||
1091 | return ret; | ||
1092 | if (*off + sizeof(struct GNUNET_TUN_DnsSoaRecord) > dst_len) | ||
1093 | return GNUNET_NO; | ||
1094 | sd.serial = htonl (soa->serial); | ||
1095 | sd.refresh = htonl (soa->refresh); | ||
1096 | sd.retry = htonl (soa->retry); | ||
1097 | sd.expire = htonl (soa->expire); | ||
1098 | sd.minimum = htonl (soa->minimum_ttl); | ||
1099 | GNUNET_memcpy (&dst[*off], &sd, sizeof(sd)); | ||
1100 | (*off) += sizeof(sd); | ||
1101 | return GNUNET_OK; | ||
1102 | } | ||
1103 | |||
1104 | |||
1105 | /** | ||
1106 | * Add an SRV record to the UDP packet at the given location. | ||
1107 | * | ||
1108 | * @param dst where to write the SRV record | ||
1109 | * @param dst_len number of bytes in @a dst | ||
1110 | * @param off pointer to offset where to write the SRV information (increment by bytes used) | ||
1111 | * can also change if there was an error | ||
1112 | * @param srv SRV information to write | ||
1113 | * @return #GNUNET_SYSERR if @a srv is invalid | ||
1114 | * #GNUNET_NO if @a srv did not fit | ||
1115 | * #GNUNET_OK if @a srv was added to @a dst | ||
1116 | */ | ||
1117 | int | ||
1118 | GNUNET_DNSPARSER_builder_add_srv (char *dst, | ||
1119 | size_t dst_len, | ||
1120 | size_t *off, | ||
1121 | const struct GNUNET_DNSPARSER_SrvRecord *srv) | ||
1122 | { | ||
1123 | struct GNUNET_TUN_DnsSrvRecord sd; | ||
1124 | int ret; | ||
1125 | |||
1126 | if (*off + sizeof(struct GNUNET_TUN_DnsSrvRecord) > dst_len) | ||
1127 | return GNUNET_NO; | ||
1128 | sd.prio = htons (srv->priority); | ||
1129 | sd.weight = htons (srv->weight); | ||
1130 | sd.port = htons (srv->port); | ||
1131 | GNUNET_memcpy (&dst[*off], &sd, sizeof(sd)); | ||
1132 | (*off) += sizeof(sd); | ||
1133 | if (GNUNET_OK != | ||
1134 | (ret = | ||
1135 | GNUNET_DNSPARSER_builder_add_name (dst, dst_len, off, srv->target))) | ||
1136 | return ret; | ||
1137 | return GNUNET_OK; | ||
1138 | } | ||
1139 | |||
1140 | |||
1141 | /** | ||
1142 | * Add a DNS record to the UDP packet at the given location. | ||
1143 | * | ||
1144 | * @param dst where to write the query | ||
1145 | * @param dst_len number of bytes in @a dst | ||
1146 | * @param off pointer to offset where to write the query (increment by bytes used) | ||
1147 | * must not be changed if there is an error | ||
1148 | * @param record record to write | ||
1149 | * @return #GNUNET_SYSERR if @a record is invalid | ||
1150 | * #GNUNET_NO if @a record did not fit | ||
1151 | * #GNUNET_OK if @a record was added to @a dst | ||
1152 | */ | ||
1153 | static int | ||
1154 | add_record (char *dst, | ||
1155 | size_t dst_len, | ||
1156 | size_t *off, | ||
1157 | const struct GNUNET_DNSPARSER_Record *record) | ||
1158 | { | ||
1159 | int ret; | ||
1160 | size_t start; | ||
1161 | size_t pos; | ||
1162 | struct GNUNET_TUN_DnsRecordLine rl; | ||
1163 | |||
1164 | start = *off; | ||
1165 | ret = GNUNET_DNSPARSER_builder_add_name (dst, | ||
1166 | dst_len | ||
1167 | - sizeof( | ||
1168 | struct GNUNET_TUN_DnsRecordLine), | ||
1169 | off, | ||
1170 | record->name); | ||
1171 | if (GNUNET_OK != ret) | ||
1172 | return ret; | ||
1173 | /* '*off' is now the position where we will need to write the record line */ | ||
1174 | |||
1175 | pos = *off + sizeof(struct GNUNET_TUN_DnsRecordLine); | ||
1176 | switch (record->type) | ||
1177 | { | ||
1178 | case GNUNET_DNSPARSER_TYPE_MX: | ||
1179 | ret = GNUNET_DNSPARSER_builder_add_mx (dst, dst_len, &pos, record->data.mx); | ||
1180 | break; | ||
1181 | |||
1182 | case GNUNET_DNSPARSER_TYPE_CERT: | ||
1183 | ret = | ||
1184 | GNUNET_DNSPARSER_builder_add_cert (dst, dst_len, &pos, record->data.cert); | ||
1185 | break; | ||
1186 | |||
1187 | case GNUNET_DNSPARSER_TYPE_SOA: | ||
1188 | ret = | ||
1189 | GNUNET_DNSPARSER_builder_add_soa (dst, dst_len, &pos, record->data.soa); | ||
1190 | break; | ||
1191 | |||
1192 | case GNUNET_DNSPARSER_TYPE_NS: | ||
1193 | case GNUNET_DNSPARSER_TYPE_CNAME: | ||
1194 | case GNUNET_DNSPARSER_TYPE_PTR: | ||
1195 | ret = GNUNET_DNSPARSER_builder_add_name (dst, | ||
1196 | dst_len, | ||
1197 | &pos, | ||
1198 | record->data.hostname); | ||
1199 | break; | ||
1200 | |||
1201 | case GNUNET_DNSPARSER_TYPE_SRV: | ||
1202 | ret = | ||
1203 | GNUNET_DNSPARSER_builder_add_srv (dst, dst_len, &pos, record->data.srv); | ||
1204 | break; | ||
1205 | |||
1206 | default: | ||
1207 | if (pos + record->data.raw.data_len > dst_len) | ||
1208 | { | ||
1209 | ret = GNUNET_NO; | ||
1210 | break; | ||
1211 | } | ||
1212 | GNUNET_memcpy (&dst[pos], record->data.raw.data, record->data.raw.data_len); | ||
1213 | pos += record->data.raw.data_len; | ||
1214 | ret = GNUNET_OK; | ||
1215 | break; | ||
1216 | } | ||
1217 | if (GNUNET_OK != ret) | ||
1218 | { | ||
1219 | *off = start; | ||
1220 | return GNUNET_NO; | ||
1221 | } | ||
1222 | |||
1223 | if (pos - (*off + sizeof(struct GNUNET_TUN_DnsRecordLine)) > UINT16_MAX) | ||
1224 | { | ||
1225 | /* record data too long */ | ||
1226 | *off = start; | ||
1227 | return GNUNET_NO; | ||
1228 | } | ||
1229 | rl.type = htons (record->type); | ||
1230 | rl.dns_traffic_class = htons (record->dns_traffic_class); | ||
1231 | rl.ttl = htonl ( | ||
1232 | GNUNET_TIME_absolute_get_remaining (record->expiration_time).rel_value_us | ||
1233 | / 1000LL / 1000LL); /* in seconds */ | ||
1234 | rl.data_len = htons ( | ||
1235 | (uint16_t) (pos - (*off + sizeof(struct GNUNET_TUN_DnsRecordLine)))); | ||
1236 | GNUNET_memcpy (&dst[*off], &rl, sizeof(struct GNUNET_TUN_DnsRecordLine)); | ||
1237 | *off = pos; | ||
1238 | return GNUNET_OK; | ||
1239 | } | ||
1240 | |||
1241 | |||
1242 | /** | ||
1243 | * Given a DNS packet @a p, generate the corresponding UDP payload. | ||
1244 | * Note that we do not attempt to pack the strings with pointers | ||
1245 | * as this would complicate the code and this is about being | ||
1246 | * simple and secure, not fast, fancy and broken like bind. | ||
1247 | * | ||
1248 | * @param p packet to pack | ||
1249 | * @param max maximum allowed size for the resulting UDP payload | ||
1250 | * @param buf set to a buffer with the packed message | ||
1251 | * @param buf_length set to the length of @a buf | ||
1252 | * @return #GNUNET_SYSERR if @a p is invalid | ||
1253 | * #GNUNET_NO if @a p was truncated (but there is still a result in @a buf) | ||
1254 | * #GNUNET_OK if @a p was packed completely into @a buf | ||
1255 | */ | ||
1256 | int | ||
1257 | GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p, | ||
1258 | uint16_t max, | ||
1259 | char **buf, | ||
1260 | size_t *buf_length) | ||
1261 | { | ||
1262 | struct GNUNET_TUN_DnsHeader dns; | ||
1263 | size_t off; | ||
1264 | char tmp[max]; | ||
1265 | int ret; | ||
1266 | int trc; | ||
1267 | |||
1268 | if ((p->num_queries > UINT16_MAX) || (p->num_answers > UINT16_MAX) || | ||
1269 | (p->num_authority_records > UINT16_MAX) || | ||
1270 | (p->num_additional_records > UINT16_MAX)) | ||
1271 | return GNUNET_SYSERR; | ||
1272 | dns.id = p->id; | ||
1273 | dns.flags = p->flags; | ||
1274 | dns.query_count = htons (p->num_queries); | ||
1275 | dns.answer_rcount = htons (p->num_answers); | ||
1276 | dns.authority_rcount = htons (p->num_authority_records); | ||
1277 | dns.additional_rcount = htons (p->num_additional_records); | ||
1278 | |||
1279 | off = sizeof(struct GNUNET_TUN_DnsHeader); | ||
1280 | trc = GNUNET_NO; | ||
1281 | for (unsigned int i = 0; i < p->num_queries; i++) | ||
1282 | { | ||
1283 | ret = GNUNET_DNSPARSER_builder_add_query (tmp, | ||
1284 | sizeof(tmp), | ||
1285 | &off, | ||
1286 | &p->queries[i]); | ||
1287 | if (GNUNET_SYSERR == ret) | ||
1288 | return GNUNET_SYSERR; | ||
1289 | if (GNUNET_NO == ret) | ||
1290 | { | ||
1291 | dns.query_count = htons ((uint16_t) (i - 1)); | ||
1292 | trc = GNUNET_YES; | ||
1293 | break; | ||
1294 | } | ||
1295 | } | ||
1296 | for (unsigned int i = 0; i < p->num_answers; i++) | ||
1297 | { | ||
1298 | ret = add_record (tmp, sizeof(tmp), &off, &p->answers[i]); | ||
1299 | if (GNUNET_SYSERR == ret) | ||
1300 | return GNUNET_SYSERR; | ||
1301 | if (GNUNET_NO == ret) | ||
1302 | { | ||
1303 | dns.answer_rcount = htons ((uint16_t) (i - 1)); | ||
1304 | trc = GNUNET_YES; | ||
1305 | break; | ||
1306 | } | ||
1307 | } | ||
1308 | for (unsigned int i = 0; i < p->num_authority_records; i++) | ||
1309 | { | ||
1310 | ret = add_record (tmp, sizeof(tmp), &off, &p->authority_records[i]); | ||
1311 | if (GNUNET_SYSERR == ret) | ||
1312 | return GNUNET_SYSERR; | ||
1313 | if (GNUNET_NO == ret) | ||
1314 | { | ||
1315 | dns.authority_rcount = htons ((uint16_t) (i - 1)); | ||
1316 | trc = GNUNET_YES; | ||
1317 | break; | ||
1318 | } | ||
1319 | } | ||
1320 | for (unsigned int i = 0; i < p->num_additional_records; i++) | ||
1321 | { | ||
1322 | ret = add_record (tmp, sizeof(tmp), &off, &p->additional_records[i]); | ||
1323 | if (GNUNET_SYSERR == ret) | ||
1324 | return GNUNET_SYSERR; | ||
1325 | if (GNUNET_NO == ret) | ||
1326 | { | ||
1327 | dns.additional_rcount = htons (i - 1); | ||
1328 | trc = GNUNET_YES; | ||
1329 | break; | ||
1330 | } | ||
1331 | } | ||
1332 | |||
1333 | if (GNUNET_YES == trc) | ||
1334 | dns.flags.message_truncated = 1; | ||
1335 | GNUNET_memcpy (tmp, &dns, sizeof(struct GNUNET_TUN_DnsHeader)); | ||
1336 | |||
1337 | *buf = GNUNET_malloc (off); | ||
1338 | *buf_length = off; | ||
1339 | GNUNET_memcpy (*buf, tmp, off); | ||
1340 | if (GNUNET_YES == trc) | ||
1341 | return GNUNET_NO; | ||
1342 | return GNUNET_OK; | ||
1343 | } | ||
1344 | |||
1345 | |||
1346 | /** | ||
1347 | * Convert a block of binary data to HEX. | ||
1348 | * | ||
1349 | * @param data binary data to convert | ||
1350 | * @param data_size number of bytes in @a data | ||
1351 | * @return HEX string (lower case) | ||
1352 | */ | ||
1353 | char * | ||
1354 | GNUNET_DNSPARSER_bin_to_hex (const void *data, size_t data_size) | ||
1355 | { | ||
1356 | char *ret; | ||
1357 | size_t off; | ||
1358 | const uint8_t *idata; | ||
1359 | |||
1360 | idata = data; | ||
1361 | ret = GNUNET_malloc (data_size * 2 + 1); | ||
1362 | for (off = 0; off < data_size; off++) | ||
1363 | sprintf (&ret[off * 2], "%02x", idata[off]); | ||
1364 | return ret; | ||
1365 | } | ||
1366 | |||
1367 | |||
1368 | /** | ||
1369 | * Convert a HEX string to block of binary data. | ||
1370 | * | ||
1371 | * @param hex HEX string to convert (may contain mixed case) | ||
1372 | * @param data where to write result, must be | ||
1373 | * at least `strlen(hex)/2` bytes long | ||
1374 | * @return number of bytes written to data | ||
1375 | */ | ||
1376 | size_t | ||
1377 | GNUNET_DNSPARSER_hex_to_bin (const char *hex, void *data) | ||
1378 | { | ||
1379 | size_t data_size; | ||
1380 | size_t off; | ||
1381 | uint8_t *idata; | ||
1382 | unsigned int h; | ||
1383 | char in[3]; | ||
1384 | |||
1385 | data_size = strlen (hex) / 2; | ||
1386 | idata = data; | ||
1387 | in[2] = '\0'; | ||
1388 | for (off = 0; off < data_size; off++) | ||
1389 | { | ||
1390 | in[0] = tolower ((unsigned char) hex[off * 2]); | ||
1391 | in[1] = tolower ((unsigned char) hex[off * 2 + 1]); | ||
1392 | if (1 != sscanf (in, "%x", &h)) | ||
1393 | return off; | ||
1394 | idata[off] = (uint8_t) h; | ||
1395 | } | ||
1396 | return off; | ||
1397 | } | ||
1398 | |||
1399 | |||
1400 | /* end of dnsparser.c */ | ||