4 This file is part of avahi.
6 avahi is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
11 avahi is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
14 Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with avahi; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
22 #include <netinet/in.h>
31 AvahiDnsPacket* avahi_dns_packet_new(guint max_size) {
35 max_size = AVAHI_DNS_PACKET_MAX_SIZE;
36 else if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
37 max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
39 p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
40 p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
41 p->max_size = max_size;
44 memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
48 AvahiDnsPacket* avahi_dns_packet_new_query(guint max_size) {
51 p = avahi_dns_packet_new(max_size);
52 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
56 AvahiDnsPacket* avahi_dns_packet_new_response(guint max_size) {
59 p = avahi_dns_packet_new(max_size);
60 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
64 void avahi_dns_packet_free(AvahiDnsPacket *p) {
68 g_hash_table_destroy(p->name_table);
73 void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v) {
75 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
77 ((guint16*) AVAHI_DNS_PACKET_DATA(p))[index] = g_htons(v);
80 guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) {
82 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
84 return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
87 /* Read the first label from string *name, unescape "\" and write it to dest */
88 gchar *avahi_unescape_label(gchar *dest, guint size, const gchar **name) {
111 if (**name == '\\') {
118 *(d++) = *((*name) ++);
129 guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
130 guint8 *d, *saved_ptr = NULL;
136 saved_size = p->size;
137 saved_ptr = avahi_dns_packet_extend(p, 0);
144 /* Check whether we can compress this name. */
146 if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
149 g_assert(prev >= AVAHI_DNS_PACKET_DATA(p));
150 index = (guint) (prev - AVAHI_DNS_PACKET_DATA(p));
152 g_assert(index < p->size);
154 if (index < 0x4000) {
156 if (!(t = (guint16*) avahi_dns_packet_extend(p, sizeof(guint16))))
159 *t = g_htons((0xC000 | index));
166 if (!(avahi_unescape_label(label, sizeof(label), &name)))
169 if (!(d = avahi_dns_packet_append_string(p, label)))
173 p->name_table = g_hash_table_new_full((GHashFunc) avahi_domain_hash, (GEqualFunc) avahi_domain_equal, g_free, NULL);
175 g_hash_table_insert(p->name_table, g_strdup(pname), d);
178 if (!(d = avahi_dns_packet_extend(p, 1)))
186 p->size = saved_size;
190 guint8* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v) {
194 if (!(d = avahi_dns_packet_extend(p, sizeof(guint16))))
197 *((guint16*) d) = g_htons(v);
201 guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v) {
205 if (!(d = avahi_dns_packet_extend(p, sizeof(guint32))))
208 *((guint32*) d) = g_htonl(v);
213 guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket *p, gconstpointer b, guint l) {
220 if (!(d = avahi_dns_packet_extend(p, l)))
227 guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s) {
234 if ((k = strlen(s)) >= 255)
237 if (!(d = avahi_dns_packet_extend(p, k+1)))
246 guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l) {
251 if (p->size+l > p->max_size)
254 d = AVAHI_DNS_PACKET_DATA(p) + p->size;
260 gint avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
267 flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
269 if (flags & AVAHI_DNS_FLAG_OPCODE || flags & AVAHI_DNS_FLAG_RCODE)
275 gint avahi_dns_packet_is_query(AvahiDnsPacket *p) {
278 return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
281 /* Read a label from a DNS packet, escape "\" and ".", append \0 */
282 static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
288 g_assert(ret_name_length);
289 g_assert(*ret_name_length > 0);
293 while (src_length > 0) {
294 if (*src == '.' || *src == '\\') {
295 if (*ret_name_length < 3)
298 *((*ret_name) ++) = '\\';
299 (*ret_name_length) --;
302 if (*ret_name_length < 2)
305 *((*ret_name)++) = *src;
306 (*ret_name_length) --;
317 static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
321 g_assert(p && ret_name && l);
326 if (index+1 > p->size)
329 n = AVAHI_DNS_PACKET_DATA(p)[index];
342 } else if (n <= 63) {
343 /* Uncompressed label */
348 if (index + n > p->size)
351 if ((guint) n + 1 > l)
360 if (!(escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
367 } else if ((n & 0xC0) == 0xC0) {
368 /* Compressed label */
370 if (index+2 > p->size)
373 index = ((guint) (AVAHI_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[index+1];
384 gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l) {
387 if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
394 gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v) {
398 if (p->rindex + sizeof(guint16) > p->size)
401 *ret_v = g_ntohs(*((guint16*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
402 p->rindex += sizeof(guint16);
407 gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v) {
411 if (p->rindex + sizeof(guint32) > p->size)
414 *ret_v = g_ntohl(*((guint32*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
415 p->rindex += sizeof(guint32);
420 gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l) {
425 if (p->rindex + l > p->size)
428 memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
434 gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l) {
438 g_assert(ret_string);
441 if (p->rindex >= p->size)
444 k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
446 if (p->rindex+1+k > p->size)
452 memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
462 gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
465 if (p->rindex > p->size)
468 return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
471 gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length) {
474 if (p->rindex + length > p->size)
481 AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush) {
482 gchar name[257], buf[257];
486 AvahiRecord *r = NULL;
490 g_assert(ret_cache_flush);
492 /* g_message("consume_record()"); */
494 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
495 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
496 avahi_dns_packet_consume_uint16(p, &class) < 0 ||
497 avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
498 avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
499 p->rindex + rdlength > p->size)
502 /* g_message("name = %s, rdlength = %u", name, rdlength); */
504 *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
505 class &= ~AVAHI_DNS_CACHE_FLUSH;
507 start = avahi_dns_packet_get_rptr(p);
509 r = avahi_record_new_full(name, class, type);
512 case AVAHI_DNS_TYPE_PTR:
513 case AVAHI_DNS_TYPE_CNAME:
515 /* g_message("ptr"); */
517 if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
520 r->data.ptr.name = g_strdup(buf);
524 case AVAHI_DNS_TYPE_SRV:
526 /* g_message("srv"); */
528 if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
529 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
530 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
531 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
534 r->data.srv.name = g_strdup(buf);
537 case AVAHI_DNS_TYPE_HINFO:
539 /* g_message("hinfo"); */
541 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
544 r->data.hinfo.cpu = g_strdup(buf);
546 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
549 r->data.hinfo.os = g_strdup(buf);
552 case AVAHI_DNS_TYPE_TXT:
554 /* g_message("txt"); */
557 r->data.txt.string_list = avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength);
559 if (avahi_dns_packet_skip(p, rdlength) < 0)
562 r->data.txt.string_list = NULL;
566 case AVAHI_DNS_TYPE_A:
568 /* g_message("A"); */
570 if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
575 case AVAHI_DNS_TYPE_AAAA:
577 /* g_message("aaaa"); */
579 if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
586 /* g_message("generic"); */
590 r->data.generic.data = g_memdup(avahi_dns_packet_get_rptr(p), rdlength);
592 if (avahi_dns_packet_skip(p, rdlength) < 0)
599 /* g_message("%i == %u ?", (guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
601 /* Check if we read enough data */
602 if ((guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
611 avahi_record_unref(r);
616 AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response) {
621 g_assert(ret_unicast_response);
623 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
624 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
625 avahi_dns_packet_consume_uint16(p, &class) < 0)
628 *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
629 class &= ~AVAHI_DNS_UNICAST_RESPONSE;
631 return avahi_key_new(name, class, type);
634 guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response) {
643 if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
644 !avahi_dns_packet_append_uint16(p, k->type) ||
645 !avahi_dns_packet_append_uint16(p, k->class | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
653 guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush) {
654 guint8 *t, *l, *start;
662 if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
663 !avahi_dns_packet_append_uint16(p, r->key->type) ||
664 !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
665 !avahi_dns_packet_append_uint32(p, r->ttl) ||
666 !(l = avahi_dns_packet_append_uint16(p, 0)))
669 start = avahi_dns_packet_extend(p, 0);
671 switch (r->key->type) {
673 case AVAHI_DNS_TYPE_PTR:
674 case AVAHI_DNS_TYPE_CNAME :
676 if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
681 case AVAHI_DNS_TYPE_SRV:
683 if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
684 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
685 !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
686 !avahi_dns_packet_append_name(p, r->data.srv.name))
691 case AVAHI_DNS_TYPE_HINFO:
692 if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
693 !avahi_dns_packet_append_string(p, r->data.hinfo.os))
698 case AVAHI_DNS_TYPE_TXT: {
703 size = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
705 /* g_message("appending string: %u %p", size, r->data.txt.string_list); */
707 if (!(data = avahi_dns_packet_extend(p, size)))
710 avahi_string_list_serialize(r->data.txt.string_list, data, size);
715 case AVAHI_DNS_TYPE_A:
717 if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
722 case AVAHI_DNS_TYPE_AAAA:
724 if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
731 if (r->data.generic.size &&
732 avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
741 size = avahi_dns_packet_extend(p, 0) - start;
742 g_assert(size <= 0xFFFF);
744 /* g_message("appended %u", size); */
746 * (guint16*) l = g_htons((guint16) size);
756 gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
759 return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
762 guint avahi_dns_packet_space(AvahiDnsPacket *p) {
765 g_assert(p->size <= p->max_size);
767 return p->max_size - p->size;