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。
// TCPServer.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <WinSock2.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 4096
int iPort = DEFAULT_PORT;//Port to listen for clients on
BOOL bInterface = FALSE;//Listen on the specified interface
BOOL bRecvOnly = FALSE;//Receive data only; don't echo back
TCHAR szAddress[128];//Interface to listen for clients on
//Print usage information and exit
void usage()
{
printf("usage:server[-p:x][-i:IP][-o]\n\n");
printf(" -p:x Port number to listen on\n");
printf(" -i:str Interface to listen on\n");
printf(" -o Don't echo the data back\n\n");
ExitProcess(1);
}
//Parse the command line arguments, and set some global flags
//to indicate what actions to perform
void ValidateArgs(int agrc, _TCHAR** argv)
{
for (int i = 1; i < agrc; i++)
{
if ((argv[i][0] == _T('-')) || (argv[i][0] == _T('/')))
{
switch (tolower(argv[i][1]))
{
case _T('p'):
iPort = _ttoi(&argv[i][3]);
break;
case _T('i'):
bInterface = TRUE;
if (_tcslen(argv[i]) > 3)
{
_tcscpy_s(szAddress, &argv[i][3]);
}
break;
case _T('o'):
//只接受数据
bRecvOnly = TRUE;
break;
default:
usage();
break;
}
}
}
}
DWORD WINAPI ClientThread(LPVOID lpParam)
{
SOCKET sock = (SOCKET)lpParam;
char szBuff[DEFAULT_BUFFER];
while (true)
{
//Perform a blocking recv() call
int ret = recv(sock, szBuff, DEFAULT_BUFFER, 0);
if (0 == ret)
{
break;
}
else if (SOCKET_ERROR == ret)
{
printf("recv() failed:%d\n", WSAGetLastError());
break;
}
szBuff[ret] = '\0';
printf("RECV:'%s'\n", szBuff);
//if we selected to echo the data back, do it
if (!bRecvOnly)
{
int nLeft = ret;
int idx = 0;
//make sure we write all the data
while (nLeft > 0)
{
ret = send(sock, &szBuff[idx], nLeft, 0);
if (0 == ret)
{
break;
}
else if (SOCKET_ERROR == ret)
{
printf("send() failed:%d\n", WSAGetLastError());
break;
}
nLeft -= ret;
idx += ret;
}
}
}
return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
ValidateArgs(argc, argv);
WSADATA wsd;
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
printf("Failed to load Winsock!\n");
return 1;
}
//Create our listening socket
SOCKET sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
if (sListen == SOCKET_ERROR)
{
printf("socket() failed:%d\n", WSAGetLastError());
return 1;
}
//Select the local interface, and bind to it
struct sockaddr_in local;
if (bInterface)
{
local.sin_addr.s_addr = inet_addr(szAddress);
if (local.sin_addr.s_addr == INADDR_NONE)
{
usage();
}
}
else
{
//INADDR_ANY是所有网卡地址
local.sin_addr.s_addr = htonl(INADDR_ANY);
}
local.sin_family = AF_INET;
local.sin_port = htons(iPort);
//绑定监听网卡地址和端口
if (bind(sListen, (struct sockaddr*)&local, sizeof(local)) == SOCKET_ERROR)
{
printf("bind() failed:%d\n", WSAGetLastError());
}
//开始监听客户端
listen(sListen, 8);
printf("begin accept on port:%d\n", iPort);
//In a continuous loop, wait for incoming clients.Once one
//is detected, create a thread and pass the handle off to it
while (true)
{
struct sockaddr_in client;
int iAddrSize = sizeof(client);
SOCKET sClient = accept(sListen, (struct sockaddr*)&client, &iAddrSize);
if (sClient == INVALID_SOCKET)
{
printf("accept() failed:%d\n", WSAGetLastError());
break;
}
printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
DWORD dwThreadId;
HANDLE hThread = CreateThread(NULL, 0, ClientThread, (LPVOID)sClient,
0, &dwThreadId);
if (hThread == NULL)
{
printf("CreateThread() failed:%d\n", GetLastError());
break;
}
CloseHandle(hThread);
}
closesocket(sListen);
WSACleanup();
return 0;
}
客户端代码，TCPClient.cpp。
// TCPClient.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <WinSock2.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_COUNT 5
#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 2048
#define DEFAULT_MESSAGE _T("This is a test of the emergency broadcasting system")
TCHAR szServer[128];
TCHAR szMessage[1024];
int iPort = DEFAULT_PORT;
DWORD dwCount = DEFAULT_COUNT;
BOOL bSendOnly = FALSE;
//Print usage information and exit
void usage()
{
printf("usage:client[-p:x][-s:IP][-n:x][-o]\n\n");
printf(" -p:x Remote port to send to \n");
printf(" -s:IP Server's IP address or host name\n");
printf(" -n:x Number of times to send message\n");
printf(" -o Send messages only; don't receive\n");
ExitProcess(1);
}
//Parse the command line arguments, and set some global flags
//to indicate what actions to perform
void ValidateArgs(int argc, _TCHAR** argv)
{
for (int i = 1; i < argc; i++)
{
if ((argv[i][0] == _T('-')) || (argv[i][0] == _T('/')))
{
switch (tolower(argv[i][1]))
{
case _T('p'):
if (_tcslen(argv[i]) > 3)
{
iPort = _ttoi(&argv[i][3]);
}
break;
case _T('s'):
if (_tcslen(argv[i]) > 3)
{
_tcscpy_s(szServer, &argv[i][3]);
}
break;
case _T('n'):
if (_tcslen(argv[i]) > 3)
{
dwCount = _ttol(&argv[i][3]);
}
break;
case _T('o'):
bSendOnly = TRUE;
break;
default:
usage();
break;
}
}
}
}
int _tmain(int argc, _TCHAR* argv[])
{
ValidateArgs(argc, argv);
WSADATA wsd;
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
printf("Failed to load Winsock library!\n");
return 1;
}
_tcscpy_s(szMessage, DEFAULT_MESSAGE);
//Create the socket, and attempt to connect to the server
SOCKET sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
if (sClient == INVALID_SOCKET)
{
printf("socket() failed:%d\n", WSAGetLastError());
return 1;
}
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port = htons(iPort);
//If the supplied server address wasn't in the form
//"aaa.bbb.ccc.ddd,"it's a host name, so try to resolve it
int nServerLen = (int)_tcslen(szServer);
if (0 == nServerLen)
{
struct hostent* host = gethostbyname(szServer);
if (host == NULL)
{
printf("Unable to resolve server:%s\n", szServer);
return 1;
}
CopyMemory(&server.sin_addr, host->h_addr_list[0], host->h_length);
}
else
{
server.sin_addr.s_addr = inet_addr(szServer);
}
if (connect(sClient, (struct sockaddr*)&server, sizeof(server))
== SOCKET_ERROR)
{
printf("connect() failed:%d\n", WSAGetLastError());
return 1;
}
//Send and receive data
char szBuffer[DEFAULT_BUFFER];
int ret = 0;
for (int i = 0; i < (int)dwCount; i++)
{
ret = send(sClient, szMessage, (int)_tcslen(szMessage), 0);
if (ret == 0)
{
break;
}
else if (ret == SOCKET_ERROR)
{
printf("send() failed:%d\n", WSAGetLastError());
break;
}
printf("Send %d bytes\n", ret);
if (!bSendOnly)
{
ret = recv(sClient, szBuffer, DEFAULT_BUFFER, 0);
if (ret == 0)
{
break;
}
else if (ret == SOCKET_ERROR)
{
printf("recv() failed:%d\n", WSAGetLastError());
break;
}
szBuffer[ret] = _T('\0');
printf("RECV [%d bytes]:'%s'\n", ret, szBuffer);
}
}
closesocket(sClient);
WSACleanup();
return 0;
}