Added Auto-Discovery through UDP Broadcasts

libipcamera/Discovery.go

@@ -0,0 +1,55 @@
+package libipcamera
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"time"
+)
+
+// Ports to try discovery on
+var targetPorts = []int{22600, 21600}
+
+// AutodiscoverCamera will try to find a camera using UDP Broadcasts
+func AutodiscoverCamera(verbose bool) (net.IP, error) {
+	conn, err := net.ListenPacket("udp", ":22601")
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	for _, port := range targetPorts {
+		go sendDiscoveryBroadcasts(conn, port, 5, verbose)
+	}
+
+	buffer := make([]byte, 80)
+	_, remoteAddr, err := conn.ReadFrom(buffer)
+
+	if err != nil {
+		return nil, err
+	}
+
+	udpAddr := remoteAddr.(*net.UDPAddr)
+	return udpAddr.IP, nil
+}
+
+func sendDiscoveryBroadcasts(localConn net.PacketConn, port, count int, verbose bool) {
+	broadcastAddress, err := net.ResolveUDPAddr("udp", fmt.Sprintf("255.255.255.255:%d", port))
+	if err != nil {
+		return
+	}
+
+	broadcastPacket := CreateCommandPacket(0x0114)
+
+	if verbose {
+		log.Printf("Trying Autodiscovery using UDP Port %d\n", port)
+	}
+	for i := 0; i < count; i++ {
+		_, err = localConn.WriteTo(broadcastPacket, broadcastAddress)
+
+		if err != nil {
+			return
+		}
+		time.Sleep(time.Millisecond * 500)
+	}
+}