Socks Server

[WestSide]

unit SocksServer; 

interface 

uses Windows,Winsock; 

var 
wsaData : TWSADATA; 
proxy_port:Integer; 
l_sock : TSocket; 
sock4 : SOCKADDR_IN; 
Client : TSockAddr; 
h1 : THandle; 

type TSOCKS4_REQUEST=record 
ucVersion : byte; 
ucCommand : byte; 
wDestPort : word; 
dwDestIp : dword; 
end; 
type TSOCKS5_REQUEST=record 
ucVersion : byte; 
ucCommand : byte; 
ucRzv : byte; 
ucAtyp : byte; 
dwDestIp : dword; 
wDestPort : word; 
end; 

procedure StartSocks; 

implementation 

procedure FlushRecvBufferUntil(s:TSOCKET;condition:Char); 
var 
iReceiveRes : integer; 
cDummy : char; 
begin 
repeat 
iReceiveRes := recv(s, cDummy, sizeof(cDummy), 0); 
until NOT ((iReceiveRes<>SOCKET_ERROR) and (iReceiveRes<>0) and (cDummy<>condition)); 
end; 

procedure SocksHandlerTreadProc(pParam:pointer); stdcall; 
var 
s : TSocket; 
tunnelSock : TSocket; 
iConnectResult : integer; 
iReceiveRes : integer; 
iSocketsSet : integer; 
socks4Request : TSOCKS4_REQUEST; 
socks4Response : TSOCKS4_REQUEST; 
socks5Request : TSOCKS5_REQUEST; 
socks5Response : TSOCKS5_REQUEST; 
remoteAddr : SOCKADDR_IN; 
fds_read : TFDset;//fd_set; 
tv : TTimeval; 
cSocksVersion : byte; 
nMethods : byte; 
Mbuffer : array[0..255] of byte; 
iSelectResult : integer; 
loop : integer; 
ulVal : u_long; 
swapBuffer : array[0..4096*16-1] of char; 
iRecvResult : integer; 
begin 
s := TSOCKET(pParam); 
tunnelSock := 0; 
loop := 0; 
while loop=0 do 
begin 
inc(loop); 
iConnectResult := 0; 
iReceiveRes := 0; 
iSocketsSet := 0; 
FD_ZERO(fds_read); 
FD_SET(s, fds_read); 
tv.tv_sec := 30; 
cSocksVersion := 0; 
iSelectResult := select(0, @fds_read, nil, nil, @tv); 
if (iSelectResult=SOCKET_ERROR) or (not iSelectResult>0) then break; 
ulVal := 0; 
ioctlsocket(s, FIONBIO , ulVal); 
iReceiveRes := recv(s, cSocksVersion, 1, MSG_PEEK); 

if (cSocksVersion=4) then //Socks 4 
begin 
iReceiveRes := recv(s, socks4Request, sizeof(socks4Request), 0); 
if iReceiveRes=SOCKET_ERROR then break; 
ulVal := 1; 

ioctlsocket(s, FIONBIO , ulVal); 
FlushRecvBufferUntil(s, #0); 
if socks4Request.ucCommand = 1 then 
begin 
ulVal := 0; 
ioctlsocket(s, FIONBIO, ulVal); 
remoteAddr.sin_family := AF_INET; 
move(socks4Request.dwDestIp,remoteAddr.sin_addr,si zeof(remoteAddr.sin_addr)); 
remoteAddr.sin_port := socks4Request.wDestPort; 
tunnelSock := socket(AF_INET, SOCK_STREAM, 0); 
iConnectResult := connect(tunnelSock, remoteAddr, sizeof(remoteAddr)); 
if (iConnectResult<>SOCKET_ERROR) then 
begin // 1111111111 
socks4Response.ucCommand := 90; 
socks4Response.ucVersion := 0; 
send(s, socks4Response, sizeof(socks4Response), 0); 
end 
else 
break; 
end 
else 
break; 
end; 

if (cSocksVersion=5) then //Socks 5 
begin 
iReceiveRes := recv(s,nMethods,1,0); 
if iReceiveRes=SOCKET_ERROR then break; 

recv(s,Mbuffer,nMethods,0); 
Mbuffer[0]:=5; 
Mbuffer[1]:=0; 
send(s,Mbuffer,2,0); 

recv(s, socks5Request, sizeof(socks5Request), 0); 

if iReceiveRes=SOCKET_ERROR then break; 
ulVal := 1; 
ioctlsocket(s, FIONBIO , ulVal); 
FlushRecvBufferUntil(s, #0); 
if socks5Request.ucCommand = 1 then 
begin 
ulVal := 0; 
ioctlsocket(s, FIONBIO, ulVal); 
remoteAddr.sin_family := AF_INET; 
move(socks5Request.dwDestIp,remoteAddr.sin_addr,si zeof(remoteAddr.sin_addr)); 
remoteAddr.sin_port := socks5Request.wDestPort; 
tunnelSock := socket(AF_INET, SOCK_STREAM, 0); 
iConnectResult := connect(tunnelSock, remoteAddr, sizeof(remoteAddr)); 
if (iConnectResult<>SOCKET_ERROR) then 
begin 
socks5Response.ucCommand := 90; 
socks5Response.ucVersion := 0; 
send(s, socks5Response, sizeof(socks5Response), 0); 
end 
else 
break; 
end 
else 
break; 
end; 

ulVal := 0; 
ioctlsocket(tunnelSock, FIONBIO, ulVal); 
ioctlsocket(s, FIONBIO, ulVal); 
fillchar(swapBuffer,sizeof(swapBuffer),0); 
tv.tv_sec := 2; 
while true do 
begin 
sleep(50); 
FD_ZERO(fds_read); 
FD_SET(s, fds_read); 
FD_SET(tunnelSock, fds_read); 
iSocketsSet := select(0, @fds_read, nil, nil, @tv); //if (iSocketsSet == SOCKET_ERROR) _leave; 
if iSocketsSet > 0 then 
begin 
if FD_ISSET(s, fds_read) then 
begin 
iRecvResult := recv(s, swapBuffer, sizeof(swapBuffer), MSG_PEEK); 
if (iRecvResult=0) 
then break 
else iRecvResult := recv(s, swapBuffer, sizeof(swapBuffer), 0); 
if (iRecvResult <> SOCKET_ERROR) and (iRecvResult > 0) 
then send(tunnelSock, swapBuffer, iRecvResult, 0) 
else BREAK; 
end; 

if (FD_ISSET(tunnelSock, fds_read)) then 
begin 
iRecvResult := recv(tunnelSock, swapBuffer, sizeof(swapBuffer), MSG_PEEK); 
if iRecvResult = 0 
then break 
else iRecvResult := recv(tunnelSock, swapBuffer, sizeof(swapBuffer), 0); 
if (iRecvResult <> SOCKET_ERROR) and (iRecvResult > 0) 
then send(s, swapBuffer, iRecvResult, 0) 
else break; 
end; 
end; 
end; 
end; 
closesocket(s); 
closesocket(tunnelSock); 
end; 

procedure StartSocks; 
var 
size:Integer; 
begin 
proxy_port := 1234; 
WSAStartup(MAKEWORD(2,0), wsaData); 
l_sock := socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); 
sock4.sin_family := AF_INET; 
sock4.sin_port := htons(proxy_port); 
sock4.sin_addr.s_addr := INADDR_ANY; 
Size := SizeOf(Client); 
if (Bind(l_sock,sock4,SizeOf(sock4))=0) and (Listen(l_sock,$FF)=0) then 
while true do begin 
sleep(50); 
CreateThread(nil,0,@SocksHandlerTreadProc,Pointer( accept(l_sock, @Client, @Size)),0,h1); 
end; 

end; 
end.