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
26 #include <netinet/in.h>
35 AvahiDnsPacket* avahi_dns_packet_new(guint max_size) {
39 max_size = AVAHI_DNS_PACKET_MAX_SIZE;
40 else if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
41 max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
43 p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
44 p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
45 p->max_size = max_size;
48 memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
52 AvahiDnsPacket* avahi_dns_packet_new_query(guint max_size) {
55 p = avahi_dns_packet_new(max_size);
56 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
60 AvahiDnsPacket* avahi_dns_packet_new_response(guint max_size) {
63 p = avahi_dns_packet_new(max_size);
64 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
68 void avahi_dns_packet_free(AvahiDnsPacket *p) {
72 g_hash_table_destroy(p->name_table);
77 void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v) {
79 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
81 ((guint16*) AVAHI_DNS_PACKET_DATA(p))[index] = g_htons(v);
84 guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) {
86 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
88 return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
91 /* Read the first label from string *name, unescape "\" and write it to dest */
92 gchar *avahi_unescape_label(gchar *dest, guint size, const gchar **name) {
115 if (**name == '\\') {
122 *(d++) = *((*name) ++);
133 guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
134 guint8 *d, *saved_ptr = NULL;
140 saved_size = p->size;
141 saved_ptr = avahi_dns_packet_extend(p, 0);
148 /* Check whether we can compress this name. */
150 if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
153 g_assert(prev >= AVAHI_DNS_PACKET_DATA(p));
154 index = (guint) (prev - AVAHI_DNS_PACKET_DATA(p));
156 g_assert(index < p->size);
158 if (index < 0x4000) {
160 if (!(t = (guint16*) avahi_dns_packet_extend(p, sizeof(guint16))))
163 *t = g_htons((0xC000 | index));
170 if (!(avahi_unescape_label(label, sizeof(label), &name)))
173 if (!(d = avahi_dns_packet_append_string(p, label)))
177 p->name_table = g_hash_table_new_full((GHashFunc) avahi_domain_hash, (GEqualFunc) avahi_domain_equal, g_free, NULL);
179 g_hash_table_insert(p->name_table, g_strdup(pname), d);
182 if (!(d = avahi_dns_packet_extend(p, 1)))
190 p->size = saved_size;
194 guint8* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v) {
198 if (!(d = avahi_dns_packet_extend(p, sizeof(guint16))))
201 *((guint16*) d) = g_htons(v);
205 guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v) {
209 if (!(d = avahi_dns_packet_extend(p, sizeof(guint32))))
212 *((guint32*) d) = g_htonl(v);
217 guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket *p, gconstpointer b, guint l) {
224 if (!(d = avahi_dns_packet_extend(p, l)))
231 guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s) {
238 if ((k = strlen(s)) >= 255)
241 if (!(d = avahi_dns_packet_extend(p, k+1)))
250 guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l) {
255 if (p->size+l > p->max_size)
258 d = AVAHI_DNS_PACKET_DATA(p) + p->size;
264 gint avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
271 flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
273 if (flags & AVAHI_DNS_FLAG_OPCODE || flags & AVAHI_DNS_FLAG_RCODE)
279 gint avahi_dns_packet_is_query(AvahiDnsPacket *p) {
282 return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
285 /* Read a label from a DNS packet, escape "\" and ".", append \0 */
286 static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
292 g_assert(ret_name_length);
293 g_assert(*ret_name_length > 0);
297 while (src_length > 0) {
298 if (*src == '.' || *src == '\\') {
299 if (*ret_name_length < 3)
302 *((*ret_name) ++) = '\\';
303 (*ret_name_length) --;
306 if (*ret_name_length < 2)
309 *((*ret_name)++) = *src;
310 (*ret_name_length) --;
321 static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
325 g_assert(p && ret_name && l);
330 if (index+1 > p->size)
333 n = AVAHI_DNS_PACKET_DATA(p)[index];
346 } else if (n <= 63) {
347 /* Uncompressed label */
352 if (index + n > p->size)
355 if ((guint) n + 1 > l)
364 if (!(escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
371 } else if ((n & 0xC0) == 0xC0) {
372 /* Compressed label */
374 if (index+2 > p->size)
377 index = ((guint) (AVAHI_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[index+1];
388 gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l) {
391 if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
398 gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v) {
402 if (p->rindex + sizeof(guint16) > p->size)
405 *ret_v = g_ntohs(*((guint16*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
406 p->rindex += sizeof(guint16);
411 gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v) {
415 if (p->rindex + sizeof(guint32) > p->size)
418 *ret_v = g_ntohl(*((guint32*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
419 p->rindex += sizeof(guint32);
424 gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l) {
429 if (p->rindex + l > p->size)
432 memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
438 gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l) {
442 g_assert(ret_string);
445 if (p->rindex >= p->size)
448 k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
450 if (p->rindex+1+k > p->size)
456 memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
466 gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
469 if (p->rindex > p->size)
472 return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
475 gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length) {
478 if (p->rindex + length > p->size)
485 AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush) {
486 gchar name[257], buf[257];
490 AvahiRecord *r = NULL;
494 g_assert(ret_cache_flush);
496 /* g_message("consume_record()"); */
498 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
499 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
500 avahi_dns_packet_consume_uint16(p, &class) < 0 ||
501 avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
502 avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
503 p->rindex + rdlength > p->size)
506 /* g_message("name = %s, rdlength = %u", name, rdlength); */
508 *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
509 class &= ~AVAHI_DNS_CACHE_FLUSH;
511 start = avahi_dns_packet_get_rptr(p);
513 r = avahi_record_new_full(name, class, type);
516 case AVAHI_DNS_TYPE_PTR:
517 case AVAHI_DNS_TYPE_CNAME:
519 /* g_message("ptr"); */
521 if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
524 r->data.ptr.name = g_strdup(buf);
528 case AVAHI_DNS_TYPE_SRV:
530 /* g_message("srv"); */
532 if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
533 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
534 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
535 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
538 r->data.srv.name = g_strdup(buf);
541 case AVAHI_DNS_TYPE_HINFO:
543 /* g_message("hinfo"); */
545 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
548 r->data.hinfo.cpu = g_strdup(buf);
550 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
553 r->data.hinfo.os = g_strdup(buf);
556 case AVAHI_DNS_TYPE_TXT:
558 /* g_message("txt"); */
561 r->data.txt.string_list = avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength);
563 if (avahi_dns_packet_skip(p, rdlength) < 0)
566 r->data.txt.string_list = NULL;
570 case AVAHI_DNS_TYPE_A:
572 /* g_message("A"); */
574 if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
579 case AVAHI_DNS_TYPE_AAAA:
581 /* g_message("aaaa"); */
583 if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
590 /* g_message("generic"); */
594 r->data.generic.data = g_memdup(avahi_dns_packet_get_rptr(p), rdlength);
596 if (avahi_dns_packet_skip(p, rdlength) < 0)
603 /* g_message("%i == %u ?", (guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
605 /* Check if we read enough data */
606 if ((guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
615 avahi_record_unref(r);
620 AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response) {
625 g_assert(ret_unicast_response);
627 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
628 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
629 avahi_dns_packet_consume_uint16(p, &class) < 0)
632 *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
633 class &= ~AVAHI_DNS_UNICAST_RESPONSE;
635 return avahi_key_new(name, class, type);
638 guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response) {
647 if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
648 !avahi_dns_packet_append_uint16(p, k->type) ||
649 !avahi_dns_packet_append_uint16(p, k->class | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
657 guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush) {
658 guint8 *t, *l, *start;
666 if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
667 !avahi_dns_packet_append_uint16(p, r->key->type) ||
668 !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
669 !avahi_dns_packet_append_uint32(p, r->ttl) ||
670 !(l = avahi_dns_packet_append_uint16(p, 0)))
673 start = avahi_dns_packet_extend(p, 0);
675 switch (r->key->type) {
677 case AVAHI_DNS_TYPE_PTR:
678 case AVAHI_DNS_TYPE_CNAME :
680 if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
685 case AVAHI_DNS_TYPE_SRV:
687 if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
688 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
689 !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
690 !avahi_dns_packet_append_name(p, r->data.srv.name))
695 case AVAHI_DNS_TYPE_HINFO:
696 if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
697 !avahi_dns_packet_append_string(p, r->data.hinfo.os))
702 case AVAHI_DNS_TYPE_TXT: {
707 size = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
709 /* g_message("appending string: %u %p", size, r->data.txt.string_list); */
711 if (!(data = avahi_dns_packet_extend(p, size)))
714 avahi_string_list_serialize(r->data.txt.string_list, data, size);
719 case AVAHI_DNS_TYPE_A:
721 if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
726 case AVAHI_DNS_TYPE_AAAA:
728 if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
735 if (r->data.generic.size &&
736 avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
745 size = avahi_dns_packet_extend(p, 0) - start;
746 g_assert(size <= 0xFFFF);
748 /* g_message("appended %u", size); */
750 * (guint16*) l = g_htons((guint16) size);
760 gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
763 return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
766 guint avahi_dns_packet_space(AvahiDnsPacket *p) {
769 g_assert(p->size <= p->max_size);
771 return p->max_size - p->size;