1 #include <netinet/in.h>
10 AvahiDnsPacket* avahi_dns_packet_new(guint max_size) {
14 max_size = AVAHI_DNS_PACKET_MAX_SIZE;
15 else if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
16 max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
18 p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
19 p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
20 p->max_size = max_size;
23 memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
27 AvahiDnsPacket* avahi_dns_packet_new_query(guint max_size) {
30 p = avahi_dns_packet_new(max_size);
31 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
35 AvahiDnsPacket* avahi_dns_packet_new_response(guint max_size) {
38 p = avahi_dns_packet_new(max_size);
39 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
43 void avahi_dns_packet_free(AvahiDnsPacket *p) {
47 g_hash_table_destroy(p->name_table);
52 void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v) {
54 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
56 ((guint16*) AVAHI_DNS_PACKET_DATA(p))[index] = g_htons(v);
59 guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) {
61 g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
63 return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
66 /* Read the first label from string *name, unescape "\" and write it to dest */
67 gchar *avahi_unescape_label(gchar *dest, guint size, const gchar **name) {
97 *(d++) = *((*name) ++);
108 guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
109 guint8 *d, *saved_ptr = NULL;
115 saved_size = p->size;
116 saved_ptr = avahi_dns_packet_extend(p, 0);
124 /* Check whether we can compress this name. */
126 if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
129 g_assert(prev >= AVAHI_DNS_PACKET_DATA(p));
130 index = (guint) (prev - AVAHI_DNS_PACKET_DATA(p));
132 g_assert(index < p->size);
134 if (index < 0x4000) {
136 if (!(t = (guint16*) avahi_dns_packet_extend(p, sizeof(guint16))))
139 *t = g_htons((0xC000 | index));
146 if (!(avahi_unescape_label(label, sizeof(label), &name)))
149 if (!(d = avahi_dns_packet_append_string(p, label)))
153 p->name_table = g_hash_table_new_full((GHashFunc) avahi_domain_hash, (GEqualFunc) avahi_domain_equal, g_free, NULL);
155 g_hash_table_insert(p->name_table, g_strdup(pname), d);
158 if (!(d = avahi_dns_packet_extend(p, 1)))
166 p->size = saved_size;
170 guint8* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v) {
174 if (!(d = avahi_dns_packet_extend(p, sizeof(guint16))))
177 *((guint16*) d) = g_htons(v);
181 guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v) {
185 if (!(d = avahi_dns_packet_extend(p, sizeof(guint32))))
188 *((guint32*) d) = g_htonl(v);
193 guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket *p, gconstpointer b, guint l) {
200 if (!(d = avahi_dns_packet_extend(p, l)))
207 guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s) {
214 if ((k = strlen(s)) >= 255)
217 if (!(d = avahi_dns_packet_extend(p, k+1)))
226 guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l) {
231 if (p->size+l > p->max_size)
234 d = AVAHI_DNS_PACKET_DATA(p) + p->size;
240 gint avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
247 flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
249 if (flags & AVAHI_DNS_FLAG_OPCODE || flags & AVAHI_DNS_FLAG_RCODE)
255 gint avahi_dns_packet_is_query(AvahiDnsPacket *p) {
258 return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
261 /* Read a label from a DNS packet, escape "\" and ".", append \0 */
262 static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
268 g_assert(ret_name_length);
269 g_assert(*ret_name_length > 0);
273 while (src_length > 0) {
274 if (*src == '.' || *src == '\\') {
275 if (*ret_name_length < 3)
278 *((*ret_name) ++) = '\\';
279 (*ret_name_length) --;
282 if (*ret_name_length < 2)
285 *((*ret_name)++) = *src;
286 (*ret_name_length) --;
297 static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
301 g_assert(p && ret_name && l);
306 if (index+1 > p->size)
309 n = AVAHI_DNS_PACKET_DATA(p)[index];
322 } else if (n <= 63) {
323 /* Uncompressed label */
328 if (index + n > p->size)
331 if ((guint) n + 1 > l)
340 if (!(escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
347 } else if ((n & 0xC0) == 0xC0) {
348 /* Compressed label */
350 if (index+2 > p->size)
353 index = ((guint) (AVAHI_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[index+1];
364 gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l) {
367 if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
374 gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v) {
378 if (p->rindex + sizeof(guint16) > p->size)
381 *ret_v = g_ntohs(*((guint16*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
382 p->rindex += sizeof(guint16);
387 gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v) {
391 if (p->rindex + sizeof(guint32) > p->size)
394 *ret_v = g_ntohl(*((guint32*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
395 p->rindex += sizeof(guint32);
400 gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l) {
405 if (p->rindex + l > p->size)
408 memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
414 gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l) {
418 g_assert(ret_string);
421 if (p->rindex >= p->size)
424 k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
426 if (p->rindex+1+k > p->size)
432 memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
442 gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
445 if (p->rindex > p->size)
448 return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
451 gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length) {
454 if (p->rindex + length > p->size)
461 AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush) {
462 gchar name[257], buf[257];
467 AvahiRecord *r = NULL;
471 g_assert(ret_cache_flush);
473 /* g_message("consume_record()"); */
475 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
476 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
477 avahi_dns_packet_consume_uint16(p, &class) < 0 ||
478 avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
479 avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
480 p->rindex + rdlength > p->size)
483 /* g_message("name = %s, rdlength = %u", name, rdlength); */
485 *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
486 class &= ~AVAHI_DNS_CACHE_FLUSH;
488 start = avahi_dns_packet_get_rptr(p);
490 r = avahi_record_new_full(name, class, type);
493 case AVAHI_DNS_TYPE_PTR:
494 case AVAHI_DNS_TYPE_CNAME:
496 /* g_message("ptr"); */
498 if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
501 r->data.ptr.name = g_strdup(buf);
505 case AVAHI_DNS_TYPE_SRV:
507 /* g_message("srv"); */
509 if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
510 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
511 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
512 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
515 r->data.srv.name = g_strdup(buf);
518 case AVAHI_DNS_TYPE_HINFO:
520 /* g_message("hinfo"); */
522 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
525 r->data.hinfo.cpu = g_strdup(buf);
527 if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
530 r->data.hinfo.os = g_strdup(buf);
533 case AVAHI_DNS_TYPE_TXT:
535 /* g_message("txt"); */
538 r->data.txt.string_list = avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength);
540 if (avahi_dns_packet_skip(p, rdlength) < 0)
543 r->data.txt.string_list = NULL;
547 case AVAHI_DNS_TYPE_A:
549 /* g_message("A"); */
551 if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
556 case AVAHI_DNS_TYPE_AAAA:
558 /* g_message("aaaa"); */
560 if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
567 /* g_message("generic"); */
571 r->data.generic.data = g_memdup(avahi_dns_packet_get_rptr(p), rdlength);
573 if (avahi_dns_packet_skip(p, rdlength) < 0)
580 /* g_message("%i == %u ?", (guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
582 /* Check if we read enough data */
583 if ((guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
592 avahi_record_unref(r);
597 AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response) {
602 g_assert(ret_unicast_response);
604 if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
605 avahi_dns_packet_consume_uint16(p, &type) < 0 ||
606 avahi_dns_packet_consume_uint16(p, &class) < 0)
609 *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
610 class &= ~AVAHI_DNS_UNICAST_RESPONSE;
612 return avahi_key_new(name, class, type);
615 guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response) {
624 if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
625 !avahi_dns_packet_append_uint16(p, k->type) ||
626 !avahi_dns_packet_append_uint16(p, k->class | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
634 guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush) {
635 guint8 *t, *l, *start;
643 if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
644 !avahi_dns_packet_append_uint16(p, r->key->type) ||
645 !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
646 !avahi_dns_packet_append_uint32(p, r->ttl) ||
647 !(l = avahi_dns_packet_append_uint16(p, 0)))
650 start = avahi_dns_packet_extend(p, 0);
652 switch (r->key->type) {
654 case AVAHI_DNS_TYPE_PTR:
655 case AVAHI_DNS_TYPE_CNAME :
657 if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
662 case AVAHI_DNS_TYPE_SRV:
664 if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
665 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
666 !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
667 !avahi_dns_packet_append_name(p, r->data.srv.name))
672 case AVAHI_DNS_TYPE_HINFO:
673 if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
674 !avahi_dns_packet_append_string(p, r->data.hinfo.os))
679 case AVAHI_DNS_TYPE_TXT: {
684 size = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
686 /* g_message("appending string: %u %p", size, r->data.txt.string_list); */
688 if (!(data = avahi_dns_packet_extend(p, size)))
691 avahi_string_list_serialize(r->data.txt.string_list, data, size);
696 case AVAHI_DNS_TYPE_A:
698 if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
703 case AVAHI_DNS_TYPE_AAAA:
705 if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
712 if (r->data.generic.size &&
713 avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
722 size = avahi_dns_packet_extend(p, 0) - start;
723 g_assert(size <= 0xFFFF);
725 /* g_message("appended %u", size); */
727 * (guint16*) l = g_htons((guint16) size);
737 gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
740 return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
743 guint avahi_dns_packet_space(AvahiDnsPacket *p) {
746 g_assert(p->size <= p->max_size);
748 return p->max_size - p->size;