1 #include <netinet/in.h>
10 flxDnsPacket* flx_dns_packet_new(guint max_size) {
14 max_size = FLX_DNS_PACKET_MAX_SIZE;
15 else if (max_size < FLX_DNS_PACKET_HEADER_SIZE)
16 max_size = FLX_DNS_PACKET_HEADER_SIZE;
18 p = g_malloc(sizeof(flxDnsPacket) + max_size);
19 p->size = p->rindex = FLX_DNS_PACKET_HEADER_SIZE;
20 p->max_size = max_size;
23 memset(FLX_DNS_PACKET_DATA(p), 0, p->size);
27 flxDnsPacket* flx_dns_packet_new_query(guint max_size) {
30 p = flx_dns_packet_new(max_size);
31 flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
35 flxDnsPacket* flx_dns_packet_new_response(guint max_size) {
38 p = flx_dns_packet_new(max_size);
39 flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
43 void flx_dns_packet_free(flxDnsPacket *p) {
47 g_hash_table_destroy(p->name_table);
52 void flx_dns_packet_set_field(flxDnsPacket *p, guint index, guint16 v) {
54 g_assert(index < FLX_DNS_PACKET_HEADER_SIZE);
56 ((guint16*) FLX_DNS_PACKET_DATA(p))[index] = g_htons(v);
59 guint16 flx_dns_packet_get_field(flxDnsPacket *p, guint index) {
61 g_assert(index < FLX_DNS_PACKET_HEADER_SIZE);
63 return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]);
66 /* Read the first label from string *name, unescape "\" and write it to dest */
67 gchar *flx_unescape_label(gchar *dest, guint size, const gchar **name) {
97 *(d++) = *((*name) ++);
108 guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) {
109 guint8 *d, *saved_ptr = NULL;
115 saved_size = p->size;
116 saved_ptr = flx_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 >= FLX_DNS_PACKET_DATA(p));
130 index = (guint) (prev - FLX_DNS_PACKET_DATA(p));
132 g_assert(index < p->size);
134 if (index < 0x4000) {
136 if (!(t = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
139 *t = g_htons((0xC000 | index));
146 if (!(flx_unescape_label(label, sizeof(label), &name)))
149 if (!(d = flx_dns_packet_append_string(p, label)))
153 p->name_table = g_hash_table_new_full((GHashFunc) flx_domain_hash, (GEqualFunc) flx_domain_equal, g_free, NULL);
155 g_hash_table_insert(p->name_table, g_strdup(pname), d);
158 if (!(d = flx_dns_packet_extend(p, 1)))
166 p->size = saved_size;
170 guint8* flx_dns_packet_append_uint16(flxDnsPacket *p, guint16 v) {
174 if (!(d = flx_dns_packet_extend(p, sizeof(guint16))))
177 *((guint16*) d) = g_htons(v);
181 guint8 *flx_dns_packet_append_uint32(flxDnsPacket *p, guint32 v) {
185 if (!(d = flx_dns_packet_extend(p, sizeof(guint32))))
188 *((guint32*) d) = g_htonl(v);
193 guint8 *flx_dns_packet_append_bytes(flxDnsPacket *p, gconstpointer b, guint l) {
200 if (!(d = flx_dns_packet_extend(p, l)))
207 guint8* flx_dns_packet_append_string(flxDnsPacket *p, const gchar *s) {
214 if ((k = strlen(s)) >= 255)
217 if (!(d = flx_dns_packet_extend(p, k+1)))
226 guint8 *flx_dns_packet_extend(flxDnsPacket *p, guint l) {
231 if (p->size+l > p->max_size)
234 d = FLX_DNS_PACKET_DATA(p) + p->size;
240 gint flx_dns_packet_check_valid(flxDnsPacket *p) {
247 flags = flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS);
249 if (flags & FLX_DNS_FLAG_OPCODE || flags & FLX_DNS_FLAG_RCODE)
255 gint flx_dns_packet_is_query(flxDnsPacket *p) {
258 return !(flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS) & FLX_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(flxDnsPacket *p, guint index, gchar *ret_name, guint l) {
301 g_assert(p && ret_name && l);
306 if (index+1 > p->size)
309 n = FLX_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(FLX_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) (FLX_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | FLX_DNS_PACKET_DATA(p)[index+1];
364 gint flx_dns_packet_consume_name(flxDnsPacket *p, gchar *ret_name, guint l) {
367 if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
374 gint flx_dns_packet_consume_uint16(flxDnsPacket *p, guint16 *ret_v) {
378 if (p->rindex + sizeof(guint16) > p->size)
381 *ret_v = g_ntohs(*((guint16*) (FLX_DNS_PACKET_DATA(p) + p->rindex)));
382 p->rindex += sizeof(guint16);
387 gint flx_dns_packet_consume_uint32(flxDnsPacket *p, guint32 *ret_v) {
391 if (p->rindex + sizeof(guint32) > p->size)
394 *ret_v = g_ntohl(*((guint32*) (FLX_DNS_PACKET_DATA(p) + p->rindex)));
395 p->rindex += sizeof(guint32);
400 gint flx_dns_packet_consume_bytes(flxDnsPacket *p, gpointer ret_data, guint l) {
405 if (p->rindex + l > p->size)
408 memcpy(ret_data, FLX_DNS_PACKET_DATA(p) + p->rindex, l);
414 gint flx_dns_packet_consume_string(flxDnsPacket *p, gchar *ret_string, guint l) {
418 g_assert(ret_string);
421 if (p->rindex >= p->size)
424 k = FLX_DNS_PACKET_DATA(p)[p->rindex];
426 if (p->rindex+1+k > p->size)
432 memcpy(ret_string, FLX_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
442 gconstpointer flx_dns_packet_get_rptr(flxDnsPacket *p) {
445 if (p->rindex > p->size)
448 return FLX_DNS_PACKET_DATA(p) + p->rindex;
451 gint flx_dns_packet_skip(flxDnsPacket *p, guint length) {
454 if (p->rindex + length > p->size)
461 flxRecord* flx_dns_packet_consume_record(flxDnsPacket *p, gboolean *ret_cache_flush) {
462 gchar name[257], buf[257];
471 g_assert(ret_cache_flush);
473 /* g_message("consume_record()"); */
475 if (flx_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
476 flx_dns_packet_consume_uint16(p, &type) < 0 ||
477 flx_dns_packet_consume_uint16(p, &class) < 0 ||
478 flx_dns_packet_consume_uint32(p, &ttl) < 0 ||
479 flx_dns_packet_consume_uint16(p, &rdlength) < 0 ||
480 p->rindex + rdlength > p->size)
484 /* g_message("name = %s, rdlength = %u", name, rdlength); */
486 start = flx_dns_packet_get_rptr(p);
488 r = flx_record_new_full(name, class, type);
491 case FLX_DNS_TYPE_PTR:
492 case FLX_DNS_TYPE_CNAME:
494 /* g_message("ptr"); */
496 if (flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
499 r->data.ptr.name = g_strdup(buf);
503 case FLX_DNS_TYPE_SRV:
505 /* g_message("srv"); */
507 if (flx_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
508 flx_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
509 flx_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
510 flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
513 r->data.srv.name = g_strdup(buf);
516 case FLX_DNS_TYPE_HINFO:
518 /* g_message("hinfo"); */
520 if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
523 r->data.hinfo.cpu = g_strdup(buf);
525 if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
528 r->data.hinfo.os = g_strdup(buf);
531 case FLX_DNS_TYPE_TXT:
533 /* g_message("txt"); */
536 r->data.txt.string_list = flx_string_list_parse(flx_dns_packet_get_rptr(p), rdlength);
538 if (flx_dns_packet_skip(p, rdlength) < 0)
541 r->data.txt.string_list = NULL;
547 /* g_message("A"); */
549 if (flx_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(flxIPv4Address)) < 0)
554 case FLX_DNS_TYPE_AAAA:
556 /* g_message("aaaa"); */
558 if (flx_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(flxIPv6Address)) < 0)
565 /* g_message("generic"); */
569 r->data.generic.data = g_memdup(flx_dns_packet_get_rptr(p), rdlength);
571 if (flx_dns_packet_skip(p, rdlength) < 0)
578 /* g_message("%i == %u ?", (guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
580 /* Check if we read enough data */
581 if ((guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
584 *ret_cache_flush = !!(class & FLX_DNS_CACHE_FLUSH);
585 class &= ~ FLX_DNS_CACHE_FLUSH;
598 flxKey* flx_dns_packet_consume_key(flxDnsPacket *p) {
604 if (flx_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
605 flx_dns_packet_consume_uint16(p, &type) < 0 ||
606 flx_dns_packet_consume_uint16(p, &class) < 0)
609 class &= ~ FLX_DNS_CACHE_FLUSH;
611 return flx_key_new(name, class, type);
614 guint8* flx_dns_packet_append_key(flxDnsPacket *p, flxKey *k) {
623 if (!(t = flx_dns_packet_append_name(p, k->name)) ||
624 !flx_dns_packet_append_uint16(p, k->type) ||
625 !flx_dns_packet_append_uint16(p, k->class)) {
633 guint8* flx_dns_packet_append_record(flxDnsPacket *p, flxRecord *r, gboolean cache_flush) {
634 guint8 *t, *l, *start;
642 if (!(t = flx_dns_packet_append_name(p, r->key->name)) ||
643 !flx_dns_packet_append_uint16(p, r->key->type) ||
644 !flx_dns_packet_append_uint16(p, cache_flush ? (r->key->class | FLX_DNS_CACHE_FLUSH) : (r->key->class &~ FLX_DNS_CACHE_FLUSH)) ||
645 !flx_dns_packet_append_uint32(p, r->ttl) ||
646 !(l = flx_dns_packet_append_uint16(p, 0)))
649 start = flx_dns_packet_extend(p, 0);
651 switch (r->key->type) {
653 case FLX_DNS_TYPE_PTR:
654 case FLX_DNS_TYPE_CNAME :
656 if (!(flx_dns_packet_append_name(p, r->data.ptr.name)))
661 case FLX_DNS_TYPE_SRV:
663 if (!flx_dns_packet_append_uint16(p, r->data.srv.priority) ||
664 !flx_dns_packet_append_uint16(p, r->data.srv.weight) ||
665 !flx_dns_packet_append_uint16(p, r->data.srv.port) ||
666 !flx_dns_packet_append_name(p, r->data.srv.name))
671 case FLX_DNS_TYPE_HINFO:
672 if (!flx_dns_packet_append_string(p, r->data.hinfo.cpu) ||
673 !flx_dns_packet_append_string(p, r->data.hinfo.os))
678 case FLX_DNS_TYPE_TXT: {
683 size = flx_string_list_serialize(r->data.txt.string_list, NULL, 0);
685 /* g_message("appending string: %u %p", size, r->data.txt.string_list); */
687 if (!(data = flx_dns_packet_extend(p, size)))
690 flx_string_list_serialize(r->data.txt.string_list, data, size);
697 if (!flx_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
702 case FLX_DNS_TYPE_AAAA:
704 if (!flx_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
711 if (r->data.generic.size &&
712 flx_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
721 size = flx_dns_packet_extend(p, 0) - start;
722 g_assert(size <= 0xFFFF);
724 /* g_message("appended %u", size); */
726 * (guint16*) l = g_htons((guint16) size);
736 gboolean flx_dns_packet_is_empty(flxDnsPacket *p) {
739 return p->size <= FLX_DNS_PACKET_HEADER_SIZE;
742 guint flx_dns_packet_space(flxDnsPacket *p) {
745 g_assert(p->size <= p->max_size);
747 return p->max_size - p->size;