Windows Socket & C++ Basic UDP Socket

UDP Socket

1.之間不用建立連線

2.對客戶端來說建立socket後，直接把資料丟向Server

主要兩個傳送函式sendto()、WSASendTo，兩個接收函式recvfrom() WSARecvFrom()

recvfrom:

   1: int recvfrom(

   2:     SOCKET                s,

   3:     char FAR *            buf,

   4:     int                   len,

   5:     int                   flags,   //0:無特殊行為 MSG_OOB:處理緩衝區外得資料 MSG_PEEK:會使有用的資料複製在緩衝去內，但沒有從系統緩衝區中刪除

   6:     struct sockaddr FAR * from,    //回傳傳送資料主機的位址

   7:     int FAR*              fromlen  //位址長度

   8: }

sendto():

   1: int sendto

   2: (

   3:     SOCKET                      s,

   4:     const char FAR *            buf,

   5:     int                         len,

   6:     int                         flags,

   7:     const struct sockaddr FAR * to,

   8:     int                         tolen

   9: );

建立UDP連線流程

UDP Server:

   1: #include <WinSock2.h>

   2: #include <iostream>

   3: #pragma  comment(lib,"wsock32.lib")

   4: #define BUF_SIZE 64

   5: char buf[BUF_SIZE];

   6: WSADATA wsd;

   7: SOCKET s;

   8: SOCKADDR_IN servAddr;

   9: SOCKADDR_IN clientAddr;

  10: void InitializeSocket(void)

  11: {

  12:     if(WSAStartup(MAKEWORD(2,2),&wsd) != 0)

  13:     {

  14:         std::cout << "WSAStartup fail" << std::endl;

  15:     }

  16:     s = socket(AF_INET,SOCK_DGRAM,0);

  17:     if(s== INVALID_SOCKET)

  18:     {

  19:         std::cout << "socket() fail" <<std::endl;

  20:         WSACleanup();

  21:     }

  22: }

  23:  

  24: void BlindSocket(void)

  25: {

  26:     servAddr.sin_family = AF_INET;

  27:     servAddr.sin_port = htons((short)5000);

  28:     servAddr.sin_addr.s_addr = htonl(INADDR_ANY);

  29:  

  30:     if(bind(s,(SOCKADDR *)&servAddr,sizeof(servAddr)) == SOCKET_ERROR)

  31:     {

  32:         std::cout << "bind Fail" <<std::endl;

  33:         closesocket(s);

  34:         WSACleanup();

  35:     }

  36: }

  37:  

  38: void AcceptData(void)

  39: {

  40:     int nClientLen = sizeof(clientAddr);

  41:     ZeroMemory(buf,BUF_SIZE);

  42:     if(recvfrom(s,buf,BUF_SIZE,0,(SOCKADDR*)&clientAddr,&nClientLen) == SOCKET_ERROR)

  43:     {

  44:         std::cout << "recvfrom() fail" << std::endl;

  45:         closesocket(s);

  46:         WSACleanup();

  47:     }

  48:     std::cout << buf << std::endl;

  49: }

  50: void ReleaseSocket(void)

  51: {

  52:     closesocket(s);

  53:     WSACleanup();

  54: }

  55:  

  56: int main()

  57: {

  58:     InitializeSocket();

  59:     BlindSocket();

  60:     AcceptData();

  61:     ReleaseSocket();

  62:     return 0;

  63: }

UDP Client:(不必建立連線)

   1: #include <WinSock2.h>

   2: #include <iostream>

   3: #pragma  comment(lib,"wsock32.lib")

   4: #define BUF_SIZE 64

   5:  

   6: WSADATA wsd;

   7: SOCKET s;

   8:  

   9: char buf[BUF_SIZE];

  10: SOCKADDR_IN servAddr;

  11:  

  12: void InitializeSocketAndDLL(void)

  13: {

  14:     if(WSAStartup(MAKEWORD(2,2),&wsd) !=0)

  15:     {

  16:         std::cout << "WSAStartup failed" << std::endl;

  17:     }

  18:     

  19:     s = socket(AF_INET,SOCK_DGRAM,0);

  20:     if(s == INVALID_SOCKET)

  21:     {

  22:         std::cout << "socket fail" << std::endl;

  23:         WSACleanup();

  24:     }

  25: }

  26:  

  27: void SendDataToServer(void)

  28: {

  29:     ZeroMemory(buf,BUF_SIZE);

  30:     strcpy(buf,"MYUDP");

  31:     servAddr.sin_family = AF_INET;

  32:     servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

  33:     servAddr.sin_port = htons((short)5000);

  34:     int nServAddlen = sizeof(servAddr);

  35:  

  36:     if(sendto(s,buf,BUF_SIZE,0,(SOCKADDR*)&servAddr,nServAddlen) == SOCKET_ERROR)

  37:     {

  38:         std::cout << "recvfrom fail" << std::endl;

  39:         closesocket(s);

  40:         WSACleanup();

  41:     }

  42: }

  43:  

  44: void ReleaseSocket(void)

  45: {

  46:     closesocket(s);

  47:     WSACleanup();

  48: }

  49:  

  50: int main()

  51: {

  52:     InitializeSocketAndDLL();

  53:     SendDataToServer();

  54:     ReleaseSocket();

  55:     return 0;

  56: }

Socket選項

getsockopt():

   1: int getsockopt

   2: {

   3:     SOCKET     s,         

   4:     int        level,    //選項級別，SOL_SOCKET、IPPROTO_TCP

   5:     int        optname,  //Socket選項名稱

   6:     char FAR*  optval,   //接收資料緩衝區，該參數回傳Socket選項名稱對應的值

   7:     int  FAR*  optlen    //緩衝區大小

   8: };

setsockopt():

   1: int setsockopt(

   2:     SOCKET     s,

   3:     int        level,

   4:     int        optname,     //Socke選項名稱

   5:     const char FAR * optval,//設置Socket選項的值

   6:     int        optlen

   7: );

最後連線流程比較

TCP Socket Server&Client	UDP Socket Server&Client