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优化代码逻辑；增加简单身份验证，即IP验证，解决了IP导致的发送失败的问题。
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@ChrysanHua
ChrysanHua committed Mar 12, 2019
1 parent efd2456 commit aa1c224
Showing 1 changed file with 125 additions and 51 deletions.
176 changes: 125 additions & 51 deletions Program.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,13 +13,61 @@ namespace SocketSingleSend
class Program
{
private const string ANSWER_FLAG = ">>OK<<";
private const string IP_FLAG = ">>IP<<";
private const int MAX_BYTE_SIZE = 256;
static readonly IPAddress localIP = Dns.GetHostAddresses(Dns.GetHostName())[1];
static readonly int PORT = 10019;
static readonly int AS_PORT = 11019;
private const int PORT = 10019;
private const int AS_PORT = 11019;
static readonly IPAddress localIP = Dns.GetHostAddresses(Dns.GetHostName()).Last();

static bool sendFail = true;
static Socket udpSender;
static Socket udpReceiver;
static Dictionary<IPAddress, IPAddress> senderDic;

#region UtilMethod
static bool SteadySend(string str, IPEndPoint targetIPE)
{
int count = 3;
while (count > 0)
{
count--;
if (UDPSend(str, targetIPE))
{
#if DEBUG
Console.WriteLine("<<<<<<<<send '{0}' to: {1}", str, targetIPE);
#endif
return true;
}
}
return false;
}

static IPAddress StrToIP(string ipStr)
{
try
{
return IPAddress.Parse(ipStr);
}
catch (Exception ex)
{
#if DEBUG
Console.WriteLine(ex.Message);
#endif
}
return null;
}

static IPEndPoint CreateIPE(IPAddress ip, int port)
{
return new IPEndPoint(ip, port);
}

static EndPoint CreateEmptyEP()
{
return CreateIPE(IPAddress.Any, 0);
}

#endregion

static void Main(string[] args)
{
Expand All @@ -28,27 +76,17 @@ static void Main(string[] args)
Console.WriteLine("3. Loop Send ;");
#endif
Console.WriteLine("Make a choice to do(1 or 2):");
//实现IP检测，即通信开始前发送IP

string choice = Console.ReadLine();
if (choice == "1")
{
//do Send
InitSocket("UDP", true);
InitSocket(true, true);
IPAddress targetIP = null;
bool flag = false;
while (!flag)
while (targetIP == null)
{
Console.WriteLine("Enter the other side's IP:");
try
{
targetIP = IPAddress.Parse(Console.ReadLine());
flag = true;
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
targetIP = StrToIP(Console.ReadLine().Trim());
}
Console.WriteLine("Write down your text:");
Console.WriteLine("-----------------------------------");
Expand All @@ -73,7 +111,7 @@ static void Main(string[] args)
else if (choice == "2")
{
//do Receive
InitSocket("UDP", false);
InitSocket(true, false);
Console.WriteLine("Local IP is: " + localIP);
Console.WriteLine("Waiting to receive the Msg...");
Console.WriteLine("-----------------------------------");
Expand All @@ -88,13 +126,16 @@ static void Main(string[] args)
#if DEBUG
else if (choice == "3")
{
//Loop Send Test
InitSocket("UDP", true);
//Loop Send for Test
InitSocket(true, true);
IPAddress targetIP = null;
string str = null;
int count = 0;
Console.WriteLine("Enter the other side's IP:");
targetIP = IPAddress.Parse(Console.ReadLine());
while (targetIP == null)
{
Console.WriteLine("Enter the other side's IP:");
targetIP = StrToIP(Console.ReadLine().Trim());
}
Console.WriteLine("-----------------------------------");
while (true)
{
Expand All @@ -112,40 +153,33 @@ static void Main(string[] args)

static string ReceiveText()
{
IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
EndPoint remoteIPE = sender;
//UDP Mode
EndPoint remoteIPE = CreateEmptyEP();
string receiveStr = UDPReceive(ref remoteIPE);
if (receiveStr != null)
{
//Send answer
IPEndPoint answerIPE = (IPEndPoint)remoteIPE;
answerIPE.Port = AS_PORT;
int count = 3;
while (count > 0)
{
count--;
if (UDPSend(ANSWER_FLAG + receiveStr, answerIPE))
{
#if DEBUG
Console.WriteLine("<<<<<<<<send '{0}' to: {1}", ANSWER_FLAG, answerIPE);
#endif
break;
}
}
}
if (receiveStr == null)
return receiveStr;
//judge whether it is IP or not and check in
if (IPCheckIn(receiveStr, remoteIPE))
return null;
//get the useful IP
IPAddress answerIP = IPCheckOut(remoteIPE);
if (answerIP == null)
return receiveStr;
//Send answer
SteadySend(ANSWER_FLAG + receiveStr, CreateIPE(answerIP, AS_PORT));
return receiveStr;
}

static bool SendText(string str, IPAddress targetIP)
{
IPEndPoint targetIPE = new IPEndPoint(targetIP, PORT);
IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
EndPoint remoteIPE = sender;
//UDP Mode
EndPoint remoteIPE = CreateEmptyEP();
//send localIP to Receiver if sendFail
if (sendFail)
SendIP(targetIP);
//clean up the buffer
FlushReceiveBuf();
if (UDPSend(str, targetIPE))
if (UDPSend(str, CreateIPE(targetIP, PORT)))
{
//Receive answer
string answerStr = null;
Expand All @@ -157,9 +191,13 @@ static bool SendText(string str, IPAddress targetIP)
#endif
if (answerStr != null &&
answerStr.StartsWith(ANSWER_FLAG) && answerStr.EndsWith(str))
{
sendFail = false;
return true;
}
} while (answerStr != null);
}
sendFail = true;
return false;
}

Expand Down Expand Up @@ -200,10 +238,10 @@ static string UDPReceive(ref EndPoint remoteIPE)
return null;
}

static void InitSocket(string protocolMode, bool sendMode)
static void InitSocket(bool udpMode, bool sendMode)
{
//Init Socket
if (protocolMode == "UDP")
if (udpMode)
{
udpReceiver = new Socket(AddressFamily.InterNetwork,
SocketType.Dgram, ProtocolType.Udp);
Expand All @@ -214,19 +252,21 @@ static void InitSocket(string protocolMode, bool sendMode)
};
if (sendMode)
{
udpReceiver.Bind(new IPEndPoint(localIP, AS_PORT));
udpReceiver.Bind(CreateIPE(localIP, AS_PORT));
udpReceiver.ReceiveTimeout = 2500;
}
else
udpReceiver.Bind(new IPEndPoint(localIP, PORT));
{
udpReceiver.Bind(CreateIPE(localIP, PORT));
senderDic = new Dictionary<IPAddress, IPAddress>();
}
}
}

static void FlushReceiveBuf()
{
//this method will only be invoked before receiving a answer
IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
EndPoint remoteIPE = sender;
EndPoint remoteIPE = CreateEmptyEP();
//clean up the Receive Buffer
while (udpReceiver.Available != 0)
{
Expand All @@ -239,5 +279,39 @@ static void FlushReceiveBuf()
}
}

static IPAddress IPCheckOut(EndPoint remoteIPE)
{
//get the useful IP if it has been checked in
IPAddress remoteIP = ((IPEndPoint)remoteIPE).Address;
//check if the IP has been checked in
if (senderDic.ContainsKey(remoteIP))
return senderDic[remoteIP];
else
return null;
}

static bool IPCheckIn(string receiveStr, EndPoint remoteIPE)
{
//check in the Sender's IP
if (!receiveStr.StartsWith(IP_FLAG))
return false;
IPAddress receiveIP = null;
//Value
receiveIP = StrToIP(receiveStr.Substring(IP_FLAG.Length));
if (receiveIP == null)
return false;
//Key
IPAddress remoteIP = ((IPEndPoint)remoteIPE).Address;
senderDic[remoteIP] = receiveIP;
return true;
}

static void SendIP(IPAddress targetIP)
{
//this method will only be invoked before sending the text
//send localIP to the Receiver
SteadySend(IP_FLAG + localIP, CreateIPE(targetIP, PORT));
}

}
}

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