穿透代理服务器编程

在日常工作和学习的时，我们时常要和代理服务器打交道,
比如通过企业、校园局域网上网的时候，一般代理服务器都支持几种常见的代理协议标准，如Socks4,Socks5,Http代理，其中Socks5需要用户验证，代理起来比较复杂。
我在查阅一些文档和相关资料后，总结一些TCP协议穿透代理服务器的程序,希望能对大家有所帮助。

//使用到的结构
struct sock4req1
{
char VN;
char CD;
unsigned short Port;
unsigned long IPAddr;
char other;
};

struct sock4ans1
{
char VN;
char CD;
};

struct sock5req1
{
char Ver;
char nMethods;
char Methods;
};

struct sock5ans1
{
char Ver;
char Method;
};

struct sock5req2
{
char Ver;
char Cmd;
char Rsv;
char Atyp;
char other;
};

struct sock5ans2
{
char Ver;
char Rep;
char Rsv;
char Atyp;
char other;
};

struct authreq
{
char Ver;
char Ulen;
char Name;
char PLen;
char Pass;
};

struct authans
{
char Ver;
char Status;
};

//通过Socks4方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
}
char buff;
memset(buff,0,100);
struct sock4req1 *m_proxyreq;
m_proxyreq = (struct sock4req1 *)buff;
m_proxyreq->VN = 4;
m_proxyreq->CD = 1;
m_proxyreq->Port = ntohs(GetPort());
m_proxyreq->IPAddr = inet_addr(GetServerHostName());
ClientSock.Send(buff,9);
struct sock4ans1 *m_proxyans;
m_proxyans = (struct sock4ans1 *)buff;
memset(buff,0,100);
ClientSock.Receive(buff,100);
if(m_proxyans->VN != 0 || m_proxyans->CD != 90)
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}




//通过Socks5方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
}
char buff;
struct sock5req1 *m_proxyreq1;
m_proxyreq1 = (struct sock5req1 *)buff;
m_proxyreq1->Ver = 5;
m_proxyreq1->nMethods = 2;
m_proxyreq1->Methods = 0;
m_proxyreq1->Methods = 2;
ClientSock.Send(buff,4);
struct sock5ans1 *m_proxyans1;
m_proxyans1 = (struct sock5ans1 *)buff;
memset(buff,0,600);
ClientSock.Receive(buff,600);
if(m_proxyans1->Ver != 5 || (m_proxyans1->Method!=0 && m_proxyans1->Method!=2))
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
if(m_proxyans1->Method == 2)
{
int nUserLen = strlen(g_ProxyInfo.m_strProxyUser);
int nPassLen = strlen(g_ProxyInfo.m_strProxyPass);
struct authreq *m_authreq;
m_authreq = (struct authreq *)buff;
m_authreq->Ver = 1;
m_authreq->Ulen = nUserLen;
strcpy(m_authreq->Name,g_ProxyInfo.m_strProxyUser);
m_authreq->PLen = nPassLen;
strcpy(m_authreq->Pass,g_ProxyInfo.m_strProxyPass);
ClientSock.Send(buff,513);
struct authans *m_authans;
m_authans = (struct authans *)buff;
memset(buff,0,600);
ClientSock.Receive(buff,600);
if(m_authans->Ver != 1 || m_authans->Status != 0)
{
m_sError = _T("代理服务器用户验证不成功!");
ClientSock.Close();
return FALSE;
}
}
struct sock5req2 *m_proxyreq2;
m_proxyreq2 = (struct sock5req2 *)buff;
m_proxyreq2->Ver = 5;
m_proxyreq2->Cmd = 1;
m_proxyreq2->Rsv = 0;
m_proxyreq2->Atyp = 1;
unsigned long tmpLong = inet_addr(GetServerHostName());
unsigned short port = ntohs(GetPort());
memcpy(m_proxyreq2->other,&tmpLong,4);
memcpy(m_proxyreq2->other+4,&port,2);
ClientSock.Send(buff,sizeof(struct sock5req2)+5);
struct sock5ans2 *m_proxyans2;
memset(buff,0,600);
m_proxyans2 = (struct sock5ans2 *)buff;
ClientSock.Receive(buff,600);
if(m_proxyans2->Ver != 5 || m_proxyans2->Rep != 0)
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}




//通过HTTP方式代理
if( !ClientSock.Connect( g_ProxyInfo.m_strProxyIP,g_ProxyInfo.m_nProxyPort) )
{
m_sError = _T("不能连接到代理服务器!");
ClientSock.Close();
return FALSE;
}
char buff;
sprintf( buff, "%s%s:%d%s","CONNECT ",GetServerHostName(),GetPort(),"
HTTP/1.1rnUser-Agent: MyApp/0.1rnrn");
ClientSock.Send(buff,strlen(buff)); //发送请求
memset(buff,0,600);
ClientSock.Receive(buff,600);
if(strstr(buff, "HTTP/1.0 200 Connection established") == NULL) //连接不成功
{
m_sError = _T("通过代理连接主站不成功!");
ClientSock.Close();
return FALSE;
}
我们一般先与代理服务器连通，然后向代理服务器发送代理验证的用户名和密码
(如果需要,如Socks5代理)，验证成功后，再向代理服务器发送需要连接的目的
地址和端口。以上代码仅用于TCP方式连接