基于UDP的多线程网络通信程序

#ifndef _CCOMM_H_
#define _CCOMM_H_

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#include <winsock.h>
#define socklen_t	int
#pragma comment(lib, "wsock32.lib")

class CComm
{
private:
static void *ListenThread(void *data);
SOCKET ListenSocket;	// 等待接收数据的socket
sockaddr_in srv;			// 绑定地址
sockaddr_in client;			// 发送数据过来的地址

public:
CComm();
~CComm();

bool SendMsg(char *Msg, int Len, char *host, short port);
bool Listen(int PortNum);

};

#endif	// #define _CCOMM_H_

#include "CComm.h"

CComm::CComm()
{
//构造函数
ListenSocket = INVALID_SOCKET;	// 开始设置为INVALID_SOCKET

#ifdef _WIN32	// 如果是win32系统
WORD VersionRequested = MAKEWORD(1,1);
WSADATA wsaData;

WSAStartup(VersionRequested, &wsaData);	// 启动winsock服务
if ( wsaData.wVersion != VersionRequested )
{
printf("Wrong version or WinSock not loaded\n");
fflush(0);
}
#endif
}

//析构函数
CComm::~CComm()
{
if ( ListenSocket != INVALID_SOCKET )
closesocket( ListenSocket );	// 如果已经创建、则关闭

#ifdef _WIN32	// 调用WSACleanup
WSACleanup();
#endif
}

bool CComm::SendMsg( char *Msg, int Len, char *host, short port )
{
signed int Sent;
hostent *hostdata;
if ( atoi(host) )	// 是否IP地址为标准形式
{
u_long ip = inet_addr( host );
hostdata = gethostbyaddr( (char *)&ip, sizeof(ip), PF_INET );
}
else	// 否则则可能是机器名
{
hostdata = gethostbyname( host );
}

if ( !hostdata )
{
printf("获得机器名错误\n");
fflush(0);
return false;
}

sockaddr_in dest;	// 发送目标地址
dest.sin_family = PF_INET;
dest.sin_addr = *(in_addr *)(hostdata->h_addr_list[0]);
dest.sin_port = htons( port );
printf("信息已经被发送到主机 %s 端口为 %i\n", inet_ntoa(dest.sin_addr), ntohs(dest.sin_port));
//数据发送
Sent = sendto(ListenSocket, Msg, Len, 0, (sockaddr *)&dest, sizeof(sockaddr_in));

if ( Sent != Len )
{
printf("错误发送UDP信息\n");
fflush(0);
return false;
}

return true;
}

void *CComm::ListenThread( void *data )
{
char buf[4096];
CComm *Comm = (CComm *)data;
int len = sizeof(Comm->client);
while(1)	// 一直循环
{
//接收数据
int result = recvfrom( Comm->ListenSocket, buf, sizeof(buf)-1, 0, (sockaddr *)&Comm->client, (socklen_t *)&len);
if ( result > 0 )
{
buf[result] = 0;
printf("Message received from host %s port %i\n", inet_ntoa(Comm->client.sin_addr), ntohs(Comm->client.sin_port));
printf(">> %s", buf);
fflush(0);
}
}
}

//地址绑定，注意在UDP协议中，不需要listen，这里函数listen只是绑定一个端口
bool CComm::Listen( int PortNum )
{
ListenSocket = socket(PF_INET, SOCK_DGRAM, 0);
if ( ListenSocket == INVALID_SOCKET )
{
printf("Error: socket创建失败\n");
fflush(0);
return false;
}

srv.sin_family = PF_INET;
srv.sin_addr.s_addr = htonl( INADDR_ANY );	// 任何地址
srv.sin_port = htons( PortNum );

if ( bind( ListenSocket, (struct sockaddr *)&srv, sizeof(srv)) != 0 )
{
printf("Error: 绑定失败\n");
fflush(0);
closesocket( ListenSocket );
return false;
}

int ThreadID;	// 线程id

DWORD thread;
//调用createthread创建线程
ThreadID = (int)CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)(CComm::ListenThread), (void *)this, 0, &thread);
ThreadID = ThreadID ? 0 : 1;	// 如果成功，则返回为0

if(ThreadID)	// ThreadID如果不为0，则线程创建失败
{
printf("线程创建失败\n");
return false;
}
else
return true;
}