diff --git a/lib/include/chiaki/discovery.h b/lib/include/chiaki/discovery.h
index 51835d7..745c5df 100644
--- a/lib/include/chiaki/discovery.h
+++ b/lib/include/chiaki/discovery.h
@@ -19,6 +19,10 @@
 #define CHIAKI_DISCOVERY_H
 
 #include "common.h"
+#include "thread.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -38,13 +42,26 @@ typedef struct chiaki_discovery_packet_t
 	char *protocol_version;
 } ChiakiDiscoveryPacket;
 
+CHIAKI_EXPORT int chiaki_discovery_packet_fmt(char *buf, size_t buf_size, ChiakiDiscoveryPacket *packet);
+
 typedef struct chiaki_discovery_t
 {
 	int socket;
+	struct sockaddr local_addr;
 } ChiakiDiscovery;
 
-CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_init(ChiakiDiscovery *discovery);
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_init(ChiakiDiscovery *discovery, sa_family_t family);
 CHIAKI_EXPORT void chiaki_discovery_fini(ChiakiDiscovery *discovery);
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_send(ChiakiDiscovery *discovery, ChiakiDiscoveryPacket *packet, struct sockaddr *addr, size_t addr_size);
+
+typedef struct chiaki_discovery_thread_t
+{
+	ChiakiDiscovery *discovery;
+	ChiakiThread thread;
+} ChiakiDiscoveryThread;
+
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_thread_start(ChiakiDiscoveryThread *thread);
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_thread_stop(ChiakiDiscoveryThread *thread);
 
 #ifdef __cplusplus
 }
diff --git a/lib/src/discovery.c b/lib/src/discovery.c
index 09d7479..f08250a 100644
--- a/lib/src/discovery.c
+++ b/lib/src/discovery.c
@@ -17,26 +17,96 @@
 
 #include <chiaki/discovery.h>
 
+#include <string.h>
 #include <unistd.h>
-
-#include <sys/types.h>
-#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
 
 
-static const char *packet_srch_template =
-		"SRCH * HTTP/1.1\n"
-  		"device-discovery-protocol-version:%s\n";
-
-
-CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_init(ChiakiDiscovery *discovery)
+CHIAKI_EXPORT int chiaki_discovery_packet_fmt(char *buf, size_t buf_size, ChiakiDiscoveryPacket *packet)
 {
+	const char *version_str = packet->protocol_version ? packet->protocol_version : CHIAKI_DISCOVERY_PROTOCOL_VERSION;
+	switch(packet->cmd)
+	{
+		case CHIAKI_DISCOVERY_CMD_SRCH:
+			return snprintf(buf, buf_size, "SRCH * HTTP/1.1\ndevice-discovery-protocol-version:%s\n",
+							version_str);
+		default:
+			return -1;
+	}
+}
+
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_init(ChiakiDiscovery *discovery, sa_family_t family)
+{
+	if(family != AF_INET && family != AF_INET6)
+		return CHIAKI_ERR_INVALID_DATA;
+
 	discovery->socket = socket(AF_INET, SOCK_DGRAM, 0);
 	if(discovery->socket < 0)
-		return CHIAKI_ERR_UNKNOWN;
+		return CHIAKI_ERR_NETWORK;
+
+	memset(&discovery->local_addr, 0, sizeof(discovery->local_addr));
+	discovery->local_addr.sa_family = family;
+	if(family == AF_INET6)
+	{
+		struct in6_addr anyaddr = IN6ADDR_ANY_INIT;
+		struct sockaddr_in6 *addr = (struct sockaddr_in6 *)&discovery->local_addr;
+		addr->sin6_addr = anyaddr;
+		addr->sin6_port = htons(0);
+	}
+	else // AF_INET
+	{
+		struct sockaddr_in *addr = (struct sockaddr_in *)&discovery->local_addr;
+		addr->sin_addr.s_addr = htonl(INADDR_ANY);
+		addr->sin_port = htons(0);
+	}
+
+	int r = bind(discovery->socket, &discovery->local_addr, sizeof(discovery->local_addr));
+	if(r < 0)
+	{
+		close(discovery->socket);
+		return CHIAKI_ERR_NETWORK;
+	}
+
+	const int broadcast = 1;
+	setsockopt(discovery->socket, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof(broadcast));
+
 	return CHIAKI_ERR_SUCCESS;
 }
 
 CHIAKI_EXPORT void chiaki_discovery_fini(ChiakiDiscovery *discovery)
 {
 	close(discovery->socket);
+}
+
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_send(ChiakiDiscovery *discovery, ChiakiDiscoveryPacket *packet, struct sockaddr *addr, size_t addr_size)
+{
+	if(addr->sa_family != discovery->local_addr.sa_family)
+		return CHIAKI_ERR_INVALID_DATA;
+
+	char buf[512];
+	int len = chiaki_discovery_packet_fmt(buf, sizeof(buf), packet);
+	if(len < 0)
+		return CHIAKI_ERR_UNKNOWN;
+	if((size_t)len >= sizeof(buf))
+		return CHIAKI_ERR_BUF_TOO_SMALL;
+
+	ssize_t rc = sendto(discovery->socket, buf, (size_t)len + 1, 0, addr, addr_size);
+	if(rc < 0)
+		return CHIAKI_ERR_NETWORK;
+
+	return CHIAKI_ERR_SUCCESS;
+}
+
+
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_thread_start(ChiakiDiscoveryThread *thread)
+{
+	// TODO
+	return CHIAKI_ERR_SUCCESS;
+}
+
+CHIAKI_EXPORT ChiakiErrorCode chiaki_discovery_thread_stop(ChiakiDiscoveryThread *thread)
+{
+	// TODO
+	return CHIAKI_ERR_SUCCESS;
 }
\ No newline at end of file