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TCP Socket通信学习

作者：我家小花儿 | 2024-02-26 21:15:03

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TCP Socket通信学习

学习内容，参见《Windows网络编程》 第7章 Winsock基础

服务器/客户端连接模型见下图。


服务端流程

  • 用socket或WSASocket创建一个套接字。
  • 用bind绑定套接字到本地IP地址（多网卡时，本地有多个IP）。
  • 用listen将套接字置为监听模式。
  • 通过accept或WSAAccept来接受客户连接。
  • 用send或WSASend发送信息，用recv或WSARecv接受信息。

客户端流程

  • 用socket或WSASocket创建一个套接字。
  • 解析服务器名。
  • 用connect或WSAConnect初始化一个连接。
  • 用send或WSASend发送信息，用recv或WSARecv接受信息。

使用windows的Winsock 2编程，创建win32控制台工程，进行工程配置。

  • 工程右键Properties->Configuration Properties->Linker->Input->Additional Dependencies中添加ws2_32.lib。
  • Demo代码采用Multi-Byte方式，设置Properties->Configuration Properties->General->Character Set为Use Multi-Byte Character Set。

服务端代码，TCPServer.cpp。

  1. // TCPServer.cpp : Defines the entry point for the console application.
  2. //
  3.  
  4. #include "stdafx.h"
  5. #include <WinSock2.h>
  6. #include <stdio.h>
  7. #include <stdlib.h>
  8.  
  9. #define DEFAULT_PORT 5150
  10. #define DEFAULT_BUFFER 4096
  11.  
  12. int iPort = DEFAULT_PORT;//Port to listen for clients on
  13. BOOL bInterface = FALSE;//Listen on the specified interface
  14. BOOL bRecvOnly = FALSE;//Receive data only; don't echo back
  15. TCHAR szAddress[128];//Interface to listen for clients on
  16.  
  17. //Print usage information and exit
  18. void usage()
  19. {
  20.     printf("usage:server[-p:x][-i:IP][-o]\n\n");
  21.     printf("         -p:x      Port number to listen on\n");
  22.     printf("         -i:str     Interface to listen on\n");
  23.     printf("         -o         Don't echo the data back\n\n");
  24.  
  25.     ExitProcess(1);
  26. }
  27.  
  28. //Parse the command line arguments, and set some global flags
  29. //to indicate what actions to perform
  30. void ValidateArgs(int agrc, _TCHAR** argv)
  31. {
  32.     for (int i = 1; i < agrc; i++)
  33.     {
  34.         if ((argv[i][0] == _T('-')) || (argv[i][0] == _T('/')))
  35.         {
  36.             switch (tolower(argv[i][1]))
  37.             {
  38.             case _T('p'):
  39.                 iPort = _ttoi(&argv[i][3]);
  40.                 break;
  41.             case _T('i'):
  42.                 bInterface = TRUE;
  43.                 if (_tcslen(argv[i]) > 3)
  44.                 {
  45.                     _tcscpy_s(szAddress, &argv[i][3]);
  46.                 }
  47.                 break;
  48.             case _T('o'):
  49.                 //只接受数据
  50.                 bRecvOnly = TRUE;
  51.                 break;
  52.             default:
  53.                 usage();
  54.                 break;
  55.             }
  56.         }
  57.     }
  58. }
  59.  
  60. DWORD WINAPI ClientThread(LPVOID lpParam)
  61. {
  62.     SOCKET sock = (SOCKET)lpParam;
  63.     char szBuff[DEFAULT_BUFFER];
  64.  
  65.     while (true)
  66.     {
  67.         //Perform a blocking recv() call
  68.         int ret = recv(sock, szBuff, DEFAULT_BUFFER, 0);
  69.         if (0 == ret)
  70.         {
  71.             break;
  72.         }
  73.         else if (SOCKET_ERROR == ret)
  74.         {
  75.             printf("recv() failed:%d\n", WSAGetLastError());
  76.             break;
  77.         }
  78.         szBuff[ret] = '\0';
  79.         printf("RECV:'%s'\n", szBuff);
  80.  
  81.         //if we selected to echo the data back, do it
  82.         if (!bRecvOnly)
  83.         {
  84.             int nLeft = ret;
  85.             int idx = 0;
  86.  
  87.             //make sure we write all the data
  88.             while (nLeft > 0)
  89.             {
  90.                 ret = send(sock, &szBuff[idx], nLeft, 0);
  91.                 if (0 == ret)
  92.                 {
  93.                     break;
  94.                 }
  95.                 else if (SOCKET_ERROR == ret)
  96.                 {
  97.                     printf("send() failed:%d\n", WSAGetLastError());
  98.                     break;
  99.                 }
  100.                 nLeft -= ret;
  101.                 idx += ret;
  102.             }
  103.         }
  104.     }
  105.  
  106.     return 0;
  107. }
  108.  
  109. int _tmain(int argc, _TCHAR* argv[])
  110. {
  111.     ValidateArgs(argc, argv);
  112.  
  113.     WSADATA wsd;
  114.     if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
  115.     {
  116.         printf("Failed to load Winsock!\n");
  117.         return 1;
  118.     }
  119.  
  120.     //Create our listening socket
  121.     SOCKET sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
  122.     if (sListen == SOCKET_ERROR)
  123.     {
  124.         printf("socket() failed:%d\n", WSAGetLastError());
  125.         return 1;
  126.     }
  127.  
  128.     //Select the local interface, and bind to it
  129.     struct sockaddr_in local;
  130.     if (bInterface)
  131.     {
  132.         local.sin_addr.s_addr = inet_addr(szAddress);
  133.         if (local.sin_addr.s_addr == INADDR_NONE)
  134.         {
  135.             usage();
  136.         }
  137.     }
  138.     else
  139.     {
  140.         //INADDR_ANY是所有网卡地址
  141.         local.sin_addr.s_addr = htonl(INADDR_ANY);
  142.     }
  143.     local.sin_family = AF_INET;
  144.     local.sin_port = htons(iPort);
  145.  
  146.     //绑定监听网卡地址和端口
  147.     if (bind(sListen, (struct sockaddr*)&local, sizeof(local)) == SOCKET_ERROR)
  148.     {
  149.         printf("bind() failed:%d\n", WSAGetLastError());
  150.     }
  151.     //开始监听客户端
  152.     listen(sListen, 8);
  153.  
  154.     printf("begin accept on port:%d\n", iPort);
  155.  
  156.     //In a continuous loop, wait for incoming clients.Once one
  157.     //is detected, create a thread and pass the handle off to it
  158.     while (true)
  159.     {
  160.         struct sockaddr_in client;
  161.         int iAddrSize = sizeof(client);
  162.         SOCKET sClient = accept(sListen, (struct sockaddr*)&client, &iAddrSize);
  163.         if (sClient == INVALID_SOCKET)
  164.         {
  165.             printf("accept() failed:%d\n", WSAGetLastError());
  166.             break;
  167.         }
  168.         printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
  169.  
  170.         DWORD dwThreadId;
  171.         HANDLE hThread = CreateThread(NULL, 0, ClientThread, (LPVOID)sClient,
  172.             0, &dwThreadId);
  173.         if (hThread == NULL)
  174.         {
  175.             printf("CreateThread() failed:%d\n", GetLastError());
  176.             break;
  177.         }
  178.         CloseHandle(hThread);
  179.     }
  180.     closesocket(sListen);
  181.  
  182.     WSACleanup();
  183.  
  184.     return 0;
  185. }

 

客户端代码，TCPClient.cpp。

  1. // TCPClient.cpp : Defines the entry point for the console application.
  2. //
  3.  
  4. #include "stdafx.h"
  5. #include <WinSock2.h>
  6. #include <stdio.h>
  7. #include <stdlib.h>
  8.  
  9. #define DEFAULT_COUNT 5
  10. #define DEFAULT_PORT 5150
  11. #define DEFAULT_BUFFER 2048
  12. #define DEFAULT_MESSAGE _T("This is a test of the emergency broadcasting system")
  13.  
  14. TCHAR szServer[128];
  15. TCHAR szMessage[1024];
  16.  
  17. int iPort = DEFAULT_PORT;
  18. DWORD dwCount = DEFAULT_COUNT;
  19. BOOL bSendOnly = FALSE;
  20.  
  21. //Print usage information and exit
  22. void usage()
  23. {
  24.     printf("usage:client[-p:x][-s:IP][-n:x][-o]\n\n");
  25.     printf("  -p:x     Remote port to send to \n");
  26.     printf("  -s:IP    Server's IP address or host name\n");
  27.     printf("  -n:x     Number of times to send message\n");
  28.     printf("  -o        Send messages only; don't receive\n");
  29.  
  30.     ExitProcess(1);
  31. }
  32.  
  33. //Parse the command line arguments, and set some global flags
  34. //to indicate what actions to perform
  35. void ValidateArgs(int argc, _TCHAR** argv)
  36. {
  37.     for (int i = 1; i < argc; i++)
  38.     {
  39.         if ((argv[i][0] == _T('-')) || (argv[i][0] == _T('/')))
  40.         {
  41.             switch (tolower(argv[i][1]))
  42.             {
  43.             case _T('p'):
  44.                 if (_tcslen(argv[i]) > 3)
  45.                 {
  46.                     iPort = _ttoi(&argv[i][3]);
  47.                 }
  48.                 break;
  49.             case _T('s'):
  50.                 if (_tcslen(argv[i]) > 3)
  51.                 {
  52.                     _tcscpy_s(szServer, &argv[i][3]);
  53.                 }
  54.                 break;
  55.             case _T('n'):
  56.                 if (_tcslen(argv[i]) > 3)
  57.                 {
  58.                     dwCount = _ttol(&argv[i][3]);
  59.                 }
  60.                 break;
  61.             case _T('o'):
  62.                 bSendOnly = TRUE;
  63.                 break;
  64.             default:
  65.                 usage();
  66.                 break;
  67.             }
  68.         }
  69.     }
  70. }
  71.  
  72. int _tmain(int argc, _TCHAR* argv[])
  73. {
  74.     ValidateArgs(argc, argv);
  75.  
  76.     WSADATA wsd;
  77.     if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
  78.     {
  79.         printf("Failed to load Winsock library!\n");
  80.         return 1;
  81.     }
  82.  
  83.     _tcscpy_s(szMessage, DEFAULT_MESSAGE);
  84.  
  85.     //Create the socket, and attempt to connect to the server
  86.     SOCKET sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
  87.     if (sClient == INVALID_SOCKET)
  88.     {
  89.         printf("socket() failed:%d\n", WSAGetLastError());
  90.         return 1;
  91.     }
  92.  
  93.     struct sockaddr_in server;
  94.     server.sin_family = AF_INET;
  95.     server.sin_port = htons(iPort);
  96.  
  97.     //If the supplied server address wasn't in the form
  98.     //"aaa.bbb.ccc.ddd,"it's a host name, so try to resolve it
  99.     int nServerLen = (int)_tcslen(szServer);
  100.     if (0 == nServerLen)
  101.     {
  102.         struct hostent* host = gethostbyname(szServer);
  103.         if (host == NULL)
  104.         {
  105.             printf("Unable to resolve server:%s\n", szServer);
  106.             return 1;
  107.         }
  108.  
  109.         CopyMemory(&server.sin_addr, host->h_addr_list[0], host->h_length);
  110.     }
  111.     else
  112.     {
  113.         server.sin_addr.s_addr = inet_addr(szServer);
  114.     }
  115.  
  116.     if (connect(sClient, (struct sockaddr*)&server, sizeof(server))
  117.         == SOCKET_ERROR)
  118.     {
  119.         printf("connect() failed:%d\n", WSAGetLastError());
  120.         return 1;
  121.     }
  122.  
  123.     //Send and receive data
  124.     char szBuffer[DEFAULT_BUFFER];
  125.     int ret = 0;
  126.  
  127.     for (int i = 0; i < (int)dwCount; i++)
  128.     {
  129.         ret = send(sClient, szMessage, (int)_tcslen(szMessage), 0);
  130.         if (ret == 0)
  131.         {
  132.             break;
  133.         }
  134.         else if (ret == SOCKET_ERROR)
  135.         {
  136.             printf("send() failed:%d\n", WSAGetLastError());
  137.             break;
  138.         }
  139.  
  140.         printf("Send %d bytes\n", ret);
  141.         if (!bSendOnly)
  142.         {
  143.             ret = recv(sClient, szBuffer, DEFAULT_BUFFER, 0);
  144.             if (ret == 0)
  145.             {
  146.                 break;
  147.             }
  148.             else if (ret == SOCKET_ERROR)
  149.             {
  150.                 printf("recv() failed:%d\n", WSAGetLastError());
  151.                 break;
  152.             }
  153.  
  154.             szBuffer[ret] = _T('\0');
  155.             printf("RECV [%d bytes]:'%s'\n", ret, szBuffer);
  156.         }
  157.     }
  158.     closesocket(sClient);
  159.  
  160.     WSACleanup();
  161.  
  162.     return 0;
  163. }

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