server data rx changes

client/golang/client.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+
 	//"strings"
 	"time"
 
@@ -13,6 +14,19 @@ import (
 	"github.com/google/gopacket/pcap"
 )
 
+type SaprusHeaderPacket struct {
+	Type		uint16
+	Length		uint16
+}
+
+type SaprusFileTransfer struct {
+	Header		SaprusHeaderPacket
+        Flag            uint8
+        Sequence        uint16
+        Checksum        uint16
+        Payload         []byte
+}
+
 func errCheck(err error) {
 	if err != nil {
 		panic(err)
@@ -20,8 +34,26 @@ func errCheck(err error) {
 	return
 }
 
+func createSaprusFileTransferPacket(payload []byte) SaprusFileTransfer {
+	var packet SaprusFileTransfer
+
+	packet.Header.Type = binary.BigEndian.Uint16([]byte{payload[0], payload[1]})
+	packet.Header.Length = binary.BigEndian.Uint16([]byte{payload[2], payload[3]})
+
+	packet.Flag = uint8(payload[4])
+	packet.Sequence = binary.BigEndian.Uint16([]byte{payload[5], payload[6]})
+	packet.Checksum = binary.BigEndian.Uint16([]byte{payload[7], payload[8]})
+
+	for i := uint16(0); i < packet.Header.Length - 5; i++ {
+		packet.Payload = append(packet.Payload, payload[i+9])
+	}
+
+	return packet
+}
+
 func listenDiscoverResponse(addrChan chan string, readyFlag chan int) {
 	finalMessage := ""
+	var pkt_data SaprusFileTransfer
 	handle, err := pcap.OpenLive("any", int32(1600), true, pcap.BlockForever)
 	errCheck(err)
 
@@ -33,17 +65,10 @@ func listenDiscoverResponse(addrChan chan string, readyFlag chan int) {
 	readyFlag <- 1
 
 	for pkt := range packets {
-		finalMessage = ""
-		payload := pkt.ApplicationLayer().Payload()
-		payloadLength := binary.BigEndian.Uint16([]byte{payload[2], payload[3]})
-
-		for i := uint16(0); i < payloadLength - 5; i++ {
-			finalMessage += string(payload[i+9])
-		}
-		fmt.Println(finalMessage)
-		if err == nil {
-			//addrChan <- finalMessage
-			//return
+		pkt_data = createSaprusFileTransferPacket(pkt.ApplicationLayer().Payload())
+		finalMessage += string(pkt_data.Payload)
+		if pkt_data.Flag == 2 {
+			addrChan <- finalMessage
 		}
 	}
 
@@ -109,7 +134,7 @@ func main() {
 	select {
 		case returnMSG := <- addrChan:
 			fmt.Printf("%s\n", returnMSG)
-		case <- time.After(5 * time.Second):
+		case <- time.After(60 * time.Second):
 			fmt.Printf("error\n")
 	}
 }