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Diffstat (limited to 'avahi-core/dns.c')
-rw-r--r--avahi-core/dns.c62
1 files changed, 53 insertions, 9 deletions
diff --git a/avahi-core/dns.c b/avahi-core/dns.c
index cc1463a..3435a0d 100644
--- a/avahi-core/dns.c
+++ b/avahi-core/dns.c
@@ -32,12 +32,18 @@
#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);
@@ -49,22 +55,60 @@ AvahiDnsPacket* avahi_dns_packet_new(guint 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) {
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(1, 0, 0, 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);
+
+ 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) |
+ (aa ? AVAHI_DNS_FLAG_AA : 0));
+
+ return r;
+}
+
+
void avahi_dns_packet_free(AvahiDnsPacket *p) {
g_assert(p);
@@ -654,7 +698,7 @@ guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean uni
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;
@@ -666,7 +710,7 @@ guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboole
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;