public static void paresRequestLine(NatSession session, string requestLine)
{
string[] parts = requestLine.Trim().Split(" ");
if (parts.Length == 3)
{
string url = parts[1];
session.method = parts[0];
session.pathUrl = url;
if (url.StartsWith("/"))
{
if (session.remoteHost != null)
{
session.requestUrl = $"http://{session.remoteHost}{url}";
}
}
else
{
if (session.requestUrl.StartsWith("http"))
{
session.requestUrl = url;
}
else
{
session.requestUrl = $"http://{url}";
}
}
}
}
public RemoteTcpTunnel(InetSocketAddress serverAddress, Selector selector, short portKey, Context context) : base(serverAddress, selector, portKey)
{
this.context = context;
session = NatSessionManager.getSession(portKey);
string helperDir = new StringBuilder()
.Append(VPNConstants.DATA_DIR)
.Append(TimeFormatUtil.formatYYMMDDHHMMSS(session.vpnStartTime))
.Append("/")
.Append(session.getUniqueName())
.ToString();
helper = new TcpDataSaveHelper(helperDir, context);
handler = new Handler(Looper.MainLooper);
}
public static void GetHttpHostAndRequestUrl(NatSession session, byte[] buffer, int offset, int count)
{
session.isHttp = true;
session.isHttpsSession = false;
string headerString = new string(Encoding.UTF8.GetChars(buffer), offset, count);
string[] headerLines = headerString.Split("\\r\\n");
string host = getHttpHost(headerLines);
if (!TextUtils.IsEmpty(host))
{
session.remoteHost = host;
}
paresRequestLine(session, headerLines[0]);
}
public static void parseHttpRequestHeader(NatSession session, byte[] buffer, int offset, int count)
{
try
{
switch (buffer[offset])
{
//GET
case (byte)'G':
//HEAD
case (byte)'H':
//POST, PUT
case (byte)'P':
//DELETE
case (byte)'D':
//OPTIONS
case (byte)'O':
//TRACE
case (byte)'T':
//CONNECT
case (byte)'C':
GetHttpHostAndRequestUrl(session, buffer, offset, count);
break;
//SSL
case 0x16:
session.remoteHost = GetSNI(session, buffer, offset, count);
session.isHttpsSession = true;
break;
default:
break;
}
}
catch (Exception ex)
{
if (AppDebug.isDebug)
{
//ex.printStackTrace(System.err);
}
Debug.Write($"Error: parseHost: {ex}");
}
}
public static String GetSNI(NatSession session, byte[] buffer, int offset, int count)
{
int limit = offset + count;
//TLS Client Hello
if (count > 43 && buffer[offset] == 0x16)
{
//Skip 43 byte header
offset += 43;
//read sessionID
if (offset + 1 > limit)
{
return(null);
}
int sessionIDLength = buffer[offset++] & 0xFF;
offset += sessionIDLength;
//read cipher suites
if (offset + 2 > limit)
{
return(null);
}
int cipherSuitesLength = CommonMethods.readShort(buffer, offset) & 0xFFFF;
offset += 2;
offset += cipherSuitesLength;
//read Compression method.
if (offset + 1 > limit)
{
return(null);
}
int compressionMethodLength = buffer[offset++] & 0xFF;
offset += compressionMethodLength;
if (offset == limit)
{
Debug.Write("TLS Client Hello packet doesn't contains SNI info.(offset == limit)");
return(null);
}
//read Extensions
if (offset + 2 > limit)
{
return(null);
}
int extensionsLength = CommonMethods.readShort(buffer, offset) & 0xFFFF;
offset += 2;
if (offset + extensionsLength > limit)
{
Debug.Write("TLS Client Hello packet is incomplete.");
return(null);
}
while (offset + 4 <= limit)
{
int type0 = buffer[offset++] & 0xFF;
int type1 = buffer[offset++] & 0xFF;
int length = CommonMethods.readShort(buffer, offset) & 0xFFFF;
offset += 2;
//have SNI
if (type0 == 0x00 && type1 == 0x00 && length > 5)
{
offset += 5;
length -= 5;
if (offset + length > limit)
{
return(null);
}
string serverName = new string(Encoding.UTF8.GetChars(buffer), offset, length);
Debug.Write("SNI: %s\n", serverName);
session.isHttpsSession = true;
return(serverName);
}
else
{
offset += length;
}
}
Debug.Write("TLS Client Hello packet doesn't contains Host field info.");
return(null);
}
else
{
Debug.Write("Bad TLS Client Hello packet.");
return(null);
}
}
