VC++6实现简单的代理服务器

#include "stdafx.h"
#include "Proxy.h"
#include < winsock2.h > //WINSOCKET API 2。0
#include < stdlib.h >
#include < stdio.h >
#include < string.h >

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////

#define HTTP "http://"
#define FTP "ftp://"
#define PROXYPORT 5001 //Proxy 端口
#define BUFSIZE 10240 //缓冲区大小

CWinApp theApp;

using namespace std;

UINT ProxyToServer(LPVOID pParam);
UINT UserToProxyThread(void *pParam);

struct SocketPair{
SOCKET user_proxy; //socket : 本地机器到PROXY 服务机
SOCKET proxy_server; //socket : PROXY 服务机到远程主机
BOOL IsUser_ProxyClosed; // 本地机器到PROXY 服务机状态
BOOL IsProxy_ServerClosed; // PROXY 服务机到远程主机状态
};

struct ProxyParam{
char Address[256]; // 远程主机地址
HANDLE User_SvrOK; // PROXY 服务机到远程主机的联结状态
SocketPair *pPair; // 维护一组SOCKET的指针
int Port; // 用来联结远程主机的端口
}; //这个结构用来PROXY SERVER与远程主机的信息交换.

SOCKET gListen_Socket; //用来侦听的SOCKET。

int StartServer() //启动服务
{
WSADATA wsaData;
sockaddr_in local;
SOCKET listen_socket;

if(::WSAStartup(0x202,&wsaData)!=0)
{printf("/nError in Startup session./n");WSACleanup();return -1;};

local.sin_family=AF_INET;
local.sin_addr.s_addr=INADDR_ANY;
local.sin_port=htons(PROXYPORT);

listen_socket=socket(AF_INET,SOCK_STREAM,0);
if(listen_socket==INVALID_SOCKET)
{printf("/nError in New a Socket.");WSACleanup();return -2;}

if(::bind(listen_socket,(sockaddr *)&local,sizeof(local))!=0)
{printf("/n Error in Binding socket."); WSACleanup();return -3; };

if(::listen(listen_socket,5)!=0)
{printf("/n Error in Listen."); WSACleanup(); return -4;}
gListen_Socket=listen_socket;
AfxBeginThread(UserToProxyThread,NULL); //启动侦听
return 1;
}

int CloseServer() //关闭服务
{
closesocket(gListen_Socket);
WSACleanup();
return 1;
}
//分析接收到的字符，得到远程主机地址

int GetAddressAndPort( char * str, char *address, int * port)
{
char buf[BUFSIZE], command[512], proto[128], *p;
int j;
sscanf(str,"%s%s%s",command,buf,proto);
p=strstr(buf,HTTP);
//HTTP
if(p)
{
p+=strlen(HTTP);
for(int i=0;i< strlen(p);i++)
if( *(p+i)=='/') break;
*(p+i)=0;
strcpy(address,p);
p=strstr(str,HTTP);
for(int j=0;j< i+strlen(HTTP);j++)
*(p+j)=' '; //去掉远程主机名: GET http:/www.csdn.net/ HTTP1.1 == > GET / HTTP1.1
*port=80; //缺省的 http 端口
}
else
{//FTP, 不支持, 下面的代码可以省略.
p=strstr(buf,FTP);
if(!p) return 0;
p+=strlen(FTP);
for(int i=0;i< strlen(p);i++)
if( *(p+i)=='/') break; //Get The Remote Host
*(p+i)=0;
for(j=0;j< strlen(p);j++)
if(*(p+j)==':')
{*port=atoi(p+j+1); //Get The Port
*(p+j)=0;
}
else *port=21;

strcpy(address,p);
p=strstr(str,FTP);
for(j=0;j< i+strlen(FTP);j++)
*(p+j)=' ';
}
return 1;
}

// 取到本地的数据，发往远程主机
UINT UserToProxyThread(void *pParam)
{
char Buffer[BUFSIZE];
int Len;
sockaddr_in from;
SOCKET msg_socket;
int fromlen,retval;
SocketPair SPair;
ProxyParam ProxyP;
CWinThread *pChildThread;
fromlen=sizeof(from);
msg_socket=accept(gListen_Socket,(struct sockaddr*)&from,&fromlen);
AfxBeginThread(UserToProxyThread,pParam); //启动另一侦听.
if( msg_socket==INVALID_SOCKET)
{ printf( "/nError in accept "); return -5;}
//读客户的第一行数据

SPair.IsUser_ProxyClosed=FALSE;
SPair.IsProxy_ServerClosed=TRUE;
SPair.user_proxy=msg_socket;

retval=recv(SPair.user_proxy,Buffer,sizeof(Buffer),0);

if(retval==SOCKET_ERROR)
{ printf("/nError Recv");
if(SPair.IsUser_ProxyClosed==FALSE)
{closesocket(SPair.user_proxy);
SPair.IsUser_ProxyClosed=TRUE;
}
}
if(retval==0)
{printf("Client Close connection/n");
if(SPair.IsUser_ProxyClosed==FALSE)
{closesocket(SPair.user_proxy);
SPair.IsUser_ProxyClosed=TRUE;
}
}
Len=retval;
#ifdef _DEBUG

Buffer[Len]=0;
printf("/n Received %d bytes,data[%s]from client/n",retval,Buffer);
#endif
//
SPair.IsUser_ProxyClosed=FALSE;
SPair.IsProxy_ServerClosed=TRUE;
SPair.user_proxy=msg_socket;

ProxyP.pPair=&SPair;
ProxyP.User_SvrOK=CreateEvent(NULL,TRUE,FALSE,NULL);

GetAddressAndPort( Buffer,ProxyP.Address,&ProxyP.Port);

pChildThread=AfxBeginThread(ProxyToServer,(LPVOID)&ProxyP);
::WaitForSingleObject(ProxyP.User_SvrOK,60000); //等待联结
::CloseHandle(ProxyP.User_SvrOK);

while(SPair.IsProxy_ServerClosed ==FALSE && SPair.IsUser_ProxyClosed==FALSE)
{
retval=send(SPair.proxy_server,Buffer,Len,0);
if(retval==SOCKET_ERROR)
{ printf("/n send() failed:error%d/n",WSAGetLastError());
if(SPair.IsProxy_ServerClosed==FALSE)
{
closesocket(SPair.proxy_server);
SPair.IsProxy_ServerClosed=TRUE;
}
continue;
}
retval=recv(SPair.user_proxy,Buffer,sizeof(Buffer),0);

if(retval==SOCKET_ERROR)
{ printf("/nError Recv");
if(SPair.IsUser_ProxyClosed==FALSE)
{closesocket(SPair.user_proxy);
SPair.IsUser_ProxyClosed=TRUE;
}
continue;
}
if(retval==0)
{printf("Client Close connection/n");
if(SPair.IsUser_ProxyClosed==FALSE)
{closesocket(SPair.user_proxy);
SPair.IsUser_ProxyClosed=TRUE;
}
break;
}
Len=retval;
#ifdef _DEBUG
Buffer[Len]=0;
printf("/n Received %d bytes,data[%s]from client/n",retval,Buffer);
#endif

} //End While

if(SPair.IsProxy_ServerClosed==FALSE)
{
closesocket(SPair.proxy_server);
SPair.IsProxy_ServerClosed=TRUE;
}
if(SPair.IsUser_ProxyClosed==FALSE)
{closesocket(SPair.user_proxy);
SPair.IsUser_ProxyClosed=TRUE;
}
::WaitForSingleObject(pChildThread- >m_hThread,20000); //Should check the return value
return 0;
}
// 读取远程主机数据，并发往本地客户机
UINT ProxyToServer(LPVOID pParam){
ProxyParam * pPar=(ProxyParam*)pParam;
char Buffer[BUFSIZE];
char *server_name= "localhost";
unsigned short port ;
int retval,Len;
unsigned int addr;
int socket_type ;
struct sockaddr_in server;
struct hostent *hp;
SOCKET conn_socket;

socket_type = SOCK_STREAM;
server_name = pPar- >Address;
port = pPar- >Port;

if (isalpha(server_name[0])) { /* server address is a name */
hp = gethostbyname(server_name);
}
else { /* Convert nnn.nnn address to a usable one */
addr = inet_addr(server_name);
hp = gethostbyaddr((char *)&addr,4,AF_INET);
}
if (hp == NULL ) {
fprintf(stderr,"Client: Cannot resolve address [%s]: Error %d/n",
server_name,WSAGetLastError());
::SetEvent(pPar- >User_SvrOK);
return 0;
}

//
// Copy the resolved information into the sockaddr_in structure
//
memset(&server,0,sizeof(server));
memcpy(&(server.sin_addr),hp- >h_addr,hp- >h_length);
server.sin_family = hp- >h_addrtype;
server.sin_port = htons(port);

conn_socket = socket(AF_INET,socket_type,0); /* 打开一个 socket */
if (conn_socket < 0 ) {
fprintf(stderr,"Client: Error Opening socket: Error %d/n",
WSAGetLastError());
pPar- >pPair- >IsProxy_ServerClosed=TRUE;
::SetEvent(pPar- >User_SvrOK);
return -1;
}
#ifdef _DEBUG
printf("Client connecting to: %s/n",hp- >h_name);
#endif
if (connect(conn_socket,(struct sockaddr*)&server,sizeof(server))
== SOCKET_ERROR) {
fprintf(stderr,"connect() failed: %d/n",WSAGetLastError());
pPar- >pPair- >IsProxy_ServerClosed=TRUE;
::SetEvent(pPar- >User_SvrOK);
return -1;
}
pPar- >pPair- >proxy_server=conn_socket;
pPar- >pPair- >IsProxy_ServerClosed=FALSE;
::SetEvent(pPar- >User_SvrOK);
// cook up a string to send
while(!pPar- >pPair- >IsProxy_ServerClosed &&!pPar- >pPair- >IsUser_ProxyClosed)
{
retval = recv(conn_socket,Buffer,sizeof (Buffer),0 );
if (retval == SOCKET_ERROR ) {
fprintf(stderr,"recv() failed: error %d/n",WSAGetLastError());
closesocket(conn_socket);
pPar- >pPair- >IsProxy_ServerClosed=TRUE;
break;
}
Len=retval;
if (retval == 0) {
printf("Server closed connection/n");
closesocket(conn_socket);
pPar- >pPair- >IsProxy_ServerClosed=TRUE;
break;
}

retval = send(pPar- >pPair- >user_proxy,Buffer,Len,0);
if (retval == SOCKET_ERROR) {
fprintf(stderr,"send() failed: error %d/n",WSAGetLastError());
closesocket(pPar- >pPair- >user_proxy);
pPar- >pPair- >IsUser_ProxyClosed=TRUE;
break;
}
#ifdef _DEBUG
Buffer[Len]=0;
printf("Received %d bytes, data [%s] from server/n",retval,Buffer);
#endif
}
if(pPar- >pPair- >IsProxy_ServerClosed==FALSE)
{
closesocket(pPar- >pPair- >proxy_server);
pPar- >pPair- >IsProxy_ServerClosed=TRUE;
}
if(pPar- >pPair- >IsUser_ProxyClosed==FALSE)
{closesocket(pPar- >pPair- >user_proxy);
pPar- >pPair- >IsUser_ProxyClosed=TRUE;
}
return 1;
}

 

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
int nRetCode = 0;

// 初始化SOCKET
if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
{
// 错误处理
cerr < < _T("Fatal Error: MFC initialization failed") < < endl;
nRetCode = 1;
}
else
{
// 主程序开始.
StartServer();
while(1)
if(getchar()=='q') break;
CloseServer();
}

return nRetCode;
}

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