#include "dns.h"
#include "util.h"
-AvahiDnsPacket* avahi_dns_packet_new(guint max_size) {
+AvahiDnsPacket* avahi_dns_packet_new(guint mtu) {
AvahiDnsPacket *p;
+ guint max_size;
- if (max_size <= 0)
+ if (mtu <= 0)
max_size = AVAHI_DNS_PACKET_MAX_SIZE;
- else if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
+ else if (mtu >= 48)
+ max_size = mtu - 48;
+ else
+ max_size = 0;
+
+ if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
return p;
}
-AvahiDnsPacket* avahi_dns_packet_new_query(guint max_size) {
+AvahiDnsPacket* avahi_dns_packet_new_query(guint mtu) {
AvahiDnsPacket *p;
- p = avahi_dns_packet_new(max_size);
+ p = avahi_dns_packet_new(mtu);
avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
return p;
}
-AvahiDnsPacket* avahi_dns_packet_new_response(guint max_size) {
+AvahiDnsPacket* avahi_dns_packet_new_response(guint mtu, gboolean aa) {
AvahiDnsPacket *p;
- p = avahi_dns_packet_new(max_size);
- avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+ p = avahi_dns_packet_new(mtu);
+ avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0));
return p;
}
+AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, guint mtu, gboolean copy_queries, gboolean aa) {
+ AvahiDnsPacket *r;
+ g_assert(p);
+
+ r = avahi_dns_packet_new_response(mtu, aa);
+
+ if (copy_queries) {
+ guint n, saved_rindex;
+
+ saved_rindex = p->rindex;
+ p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
+
+ for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) {
+ AvahiKey *k;
+ gboolean unicast_response;
+
+ if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) {
+ avahi_dns_packet_append_key(r, k, unicast_response);
+ avahi_key_unref(k);
+ }
+ }
+
+ p->rindex = saved_rindex;
+
+ avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT));
+ }
+
+ avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID));
+
+ avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS,
+ (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) |
+ (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE));
+
+ return r;
+}
+
+
void avahi_dns_packet_free(AvahiDnsPacket *p) {
g_assert(p);
return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
}
-/* Read the first label from string *name, unescape "\" and write it to dest */
-gchar *avahi_unescape_label(gchar *dest, guint size, const gchar **name) {
- guint i = 0;
- gchar *d;
-
- g_assert(dest);
- g_assert(size > 0);
- g_assert(name);
- g_assert(*name);
-
- d = dest;
-
- for (;;) {
- if (i >= size)
- return NULL;
-
- if (**name == '.') {
- (*name)++;
- break;
- }
-
- if (**name == 0)
- break;
-
- if (**name == '\\') {
- (*name) ++;
-
- if (**name == 0)
- break;
- }
-
- *(d++) = *((*name) ++);
- i++;
- }
+void avahi_dns_packet_inc_field(AvahiDnsPacket *p, guint index) {
+ g_assert(p);
- g_assert(i < size);
+ avahi_dns_packet_set_field(p, index, avahi_dns_packet_get_field(p, index) + 1);
+}
- *d = 0;
- return dest;
-}
guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
guint8 *d, *saved_ptr = NULL;
pname = name;
- if (!(avahi_unescape_label(label, sizeof(label), &name)))
+ if (!(avahi_unescape_label(&name, label, sizeof(label))))
goto fail;
if (!(d = avahi_dns_packet_append_string(p, label)))
goto fail;
if (!p->name_table)
- p->name_table = g_hash_table_new_full((GHashFunc) avahi_domain_hash, (GEqualFunc) avahi_domain_equal, g_free, NULL);
+ /* This works only for normalized domain names */
+ p->name_table = g_hash_table_new_full((GHashFunc) g_str_hash, (GEqualFunc) g_str_equal, g_free, NULL);
g_hash_table_insert(p->name_table, g_strdup(pname), d);
}
return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
}
-/* Read a label from a DNS packet, escape "\" and ".", append \0 */
-static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
- gchar *r;
-
- g_assert(src);
- g_assert(ret_name);
- g_assert(*ret_name);
- g_assert(ret_name_length);
- g_assert(*ret_name_length > 0);
-
- r = *ret_name;
-
- while (src_length > 0) {
- if (*src == '.' || *src == '\\') {
- if (*ret_name_length < 3)
- return NULL;
-
- *((*ret_name) ++) = '\\';
- (*ret_name_length) --;
- }
-
- if (*ret_name_length < 2)
- return NULL;
-
- *((*ret_name)++) = *src;
- (*ret_name_length) --;
-
- src_length --;
- src++;
- }
-
- **ret_name = 0;
-
- return r;
-}
-
static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
gint ret = 0;
int compressed = 0;
} else
first_label = 0;
- if (!(escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
+ if (!(avahi_escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
return -1;
index += n;
return t;
}
-guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush) {
+guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush, guint max_ttl) {
guint8 *t, *l, *start;
guint size;
if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
!avahi_dns_packet_append_uint16(p, r->key->type) ||
!avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
- !avahi_dns_packet_append_uint32(p, r->ttl) ||
+ !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) ||
!(l = avahi_dns_packet_append_uint16(p, 0)))
goto fail;
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