cache: send multiple queries in a single packet

Signed-off-by: Felix Fietkau <nbd@nbd.name>

3 files changed, 23 insertions, 9 deletions

diff --git a/cache.c b/cache.c
index 55a0e16..19577b2 100644
--- a/cache.c
+++ b/cache.c
@@ -143,16 +143,21 @@ void
 cache_update(void)
 {
 	struct cache_service *s;
-	struct interface *iface;
-
-	vlist_for_each_element(&interfaces, iface, node) {
-		dns_send_question(iface, NULL, C_DNS_SD, TYPE_ANY, interface_multicast(iface));
-		dns_send_question(iface, NULL, C_DNS_SD, TYPE_PTR, interface_multicast(iface));
-		avl_for_each_element(&services, s, avl)
-			if (!s->host)
-				dns_send_question(iface, NULL, s->entry, TYPE_PTR,
-						  interface_multicast(iface));
+	int count = 2;
+
+	dns_packet_init();
+	dns_packet_question(C_DNS_SD, TYPE_ANY);
+	dns_packet_question(C_DNS_SD, TYPE_PTR);
+	avl_for_each_element(&services, s, avl) {
+		dns_packet_question(s->entry, TYPE_PTR);
+		if (++count < 16)
+			continue;
+		dns_packet_broadcast();
+		count = 0;
 	}
+
+	if (count)
+		dns_packet_broadcast();
 }
 
 static struct cache_service*
diff --git a/dns.c b/dns.c
index ffa61ba..715125b 100644
--- a/dns.c
+++ b/dns.c
@@ -185,6 +185,14 @@ void dns_packet_send(struct interface *iface, struct sockaddr *to, bool query, i
 		perror("failed to send answer");
 }
 
+void dns_packet_broadcast(void)
+{
+	struct interface *iface;
+
+	vlist_for_each_element(&interfaces, iface, node)
+		dns_packet_send(iface, NULL, 1, -1);
+}
+
 void
 dns_send_question(struct interface *iface, struct sockaddr *to,
 		  const char *question, int type, int multicast)
diff --git a/dns.h b/dns.h
index d6991e0..65efcf7 100644
--- a/dns.h
+++ b/dns.h
@@ -77,6 +77,7 @@ void dns_packet_init(void);
 bool dns_packet_question(const char *name, int type);
 void dns_packet_answer(const char *name, int type, const uint8_t *rdata, uint16_t rdlength, int ttl);
 void dns_packet_send(struct interface *iface, struct sockaddr *to, bool query, int multicast);
+void dns_packet_broadcast(void);
 
 void dns_send_question(struct interface *iface, struct sockaddr *to,
 		       const char *question, int type, int multicast);