Пример #1
0
func main() {
	args := os.Args
	if len(args) != 4 {
		fmt.Println("Usage: [aserver UDP ip:port] [fserver RPC ip:port] [secret]")
		os.Exit(-1)
	}
	aserverUDPIpPort := args[1]
	fserverRCPIpPort := args[2]
	secret := parseSecretArg(args[3])

	udpListener := clientServerUtils.InitUDPConn(aserverUDPIpPort)

	//Initialize hash table of (udpIpPort, nonce) key-value pairs
	var nonceMap clientServerUtils.ConcurrentMap
	nonceMap.Map = make(map[string]int64)

	//Start listen/receive connection loop
	for {
		var buf [1024]byte
		msgLen, clientUDPAddr, err := udpListener.ReadFromUDP(buf[:])
		if err != nil {
			fmt.Println("Error on ReadFromUDP: ", err)
		} else {
			go handleUDPConn(udpListener, clientUDPAddr, fserverRCPIpPort, nonceMap, secret, buf[0:msgLen])
		}
	}
	udpListener.Close()
}
Пример #2
0
//Generate new nonce for udpAddr and add to nonceMap
func generateNewNonce(udpAddr *net.UDPAddr, nonceMap clientServerUtils.ConcurrentMap) int64 {
	nonce := rand.Int63()
	nonceMap.Lock()
	nonceMap.Map[udpAddr.String()] = nonce
	nonceMap.Unlock()
	return nonce
}
Пример #3
0
func handleUDPConn(udpListener net.UDPConn, clientUDPAddr *net.UDPAddr, fserverRCPIpPort string, nonceMap clientServerUtils.ConcurrentMap, secret int64, msgFromClient []byte) {
	nonceMap.RLock()
	clientNonce := nonceMap.Map[clientUDPAddr.String()]
	nonceMap.RUnlock()

	var receivedHashMsg clientServerUtils.HashMessage
	err := json.Unmarshal(msgFromClient, &receivedHashMsg)
	if err != nil {
		sendNewNonce(udpListener, clientUDPAddr, nonceMap)
	} else if clientNonce == 0 {
		errMsg := clientServerUtils.ErrMessage{"unknown remote client address"}
		sendErrMessage(udpListener, clientUDPAddr, errMsg)
	} else if isValidHashMessage(receivedHashMsg, clientNonce, secret) {
		replyWithFortuneInfoMessage(udpListener, clientUDPAddr, fserverRCPIpPort)
	} else {
		errMsg := clientServerUtils.ErrMessage{"unexpected hash value"}
		sendErrMessage(udpListener, clientUDPAddr, errMsg)
	}
}