穿透代理服务器编程

来源：互联网发布：多重宇宙知乎编辑：程序博客网时间：2024/05/16 16:12

田进恩 allfresh@263.net
关键词：代理服务器、Socks4、Socks5、Http代理
在网络程序设计过程中，我们经常要与各种类型的代理服务器打交道，比如在企业内部网通过代理去访问Internet网上的服务器等等，一般代理服务器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，代理相对复杂。我在查阅RFC文档和相关资料后，特总结一些TCP协议穿透代理服务器的程序片断，希望对大家有所帮助。

//使用到的结构
struct sock4req1
{
char VN;
char CD;
unsigned short Port;
unsigned long IPAddr;
char other[1];
};

struct sock4ans1
{
char VN;
char CD;
};

struct sock5req1
{
char Ver;
char nMethods;
char Methods[255];
};

struct sock5ans1
{
char Ver;
char Method;
};

struct sock5req2
{
char Ver;
char Cmd;
char Rsv;
char Atyp;
char other[1];
};

struct sock5ans2
{
char Ver;
char Rep;
char Rsv;
char Atyp;
char other[1];
};

struct authreq
{
char Ver;
char Ulen;
char Name[255];
char PLen;
char Pass[255];
};

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[100];
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[600];
struct sock5req1 *m_proxyreq1;
m_proxyreq1 = (struct sock5req1 *)buff;
m_proxyreq1->Ver = 5;
m_proxyreq1->nMethods = 2;
m_proxyreq1->Methods[0] = 0;
m_proxyreq1->Methods[1] = 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[600];
sprintf( buff, "%s%s:%d%s","CONNECT ",GetServerHostName(),GetPort()," HTTP/1.1/r/nUser-Agent: MyApp/0.1/r/n/r/n");
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连接，如果在内部网侦听或通过UDP协议发送信息，可查阅RFC1829等文档资料。

// 与代理服务器建立CONNECT；
int retErr = connect(m_hSocketpop,(SOCKADDR*)&ToAddr,sizeof(ToAddr));
if(retErr == SOCKET_ERROR)
{
printf("connect error");
return -1;
}
char buf[100];
// 让PROXY选择认证方法
buf[0] = 0x05;
buf[1] = 0x01;
buf[2] = 0x00; // 无需认证
send(m_hSocketpop,(const far char*)buf,3,0);
recv(m_hSocketpop,buf,10,0);
if(buf[1] != 0x00)
printf("Need to authenticate!/n");
// 向PROXY服务器发送CONNECT 请求，
WORD port = 80;
buf[0] = 0x05;
buf[1] = 0x01; // connection request.
buf[2] = 0x00; // reserved!
buf[3] = 0x01; // address type:Ip V4 ;
buf[4] = 0xd3;
buf[5] = 0x64;
buf[6] = 0x1f;
buf[7] = 0x61;
buf[8] = port/256; //0x80;
buf[9] = (BYTE)port%256; //0x00;
port += 1;
send(m_hSocketpop,(const far char*)buf,10,0);
// 接收PROXY服务器返回的REPLY
recv(m_hSocketpop,buf,20,0);
if(buf[1] != 0) // 只有当第二个字节为0时，才表示成功。
{
printf("Cannot connect to the remote server!/n");
return -1;
}
// 用PROXY服务器返回的REPLY中的地址与端口号来CONNECT 目的主机
SOCKADDR_IN SockAddr;
SOCKET prxSock;
prxSock = socket(AF_INET, SOCK_STREAM ,0); // SOCK_DGRAM
port = ((WORD)buf[8])*256 + (WORD)buf[9]; // 返回的端口号在buf[8] 和 buf[9] 中
memset(&SockAddr,0,sizeof(SockAddr));
SockAddr.sin_family = AF_INET;
SockAddr.sin_port = port;
SockAddr.sin_addr.S_un.S_un_b.s_b1 = buf[4];
SockAddr.sin_addr.S_un.S_un_b.s_b2 = buf[5];
SockAddr.sin_addr.S_un.S_un_b.s_b3 = buf[6];
SockAddr.sin_addr.S_un.S_un_b.s_b4 = buf[7];
retErr = connect(prxSock,(SOCKADDR*)&SockAddr,sizeof(SockAddr));
if(retErr == SOCKET_ERROR)
printf("error");
/*连接已经建立好了，下面你就可以用prxSock用send发送数据了。*/
char *pInfo = (char *)malloc(100);
strcpy(pInfo,"Only a test");
send(prxSock,pInfo,100,0);