using Splat;
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
namespace Shadowsocks.Net.Proxy
{
public class HttpProxy : IProxy, IEnableLogger
{
public EndPoint LocalEndPoint => _remote.LocalEndPoint;
public EndPoint ProxyEndPoint { get; private set; }
public EndPoint DestEndPoint { get; private set; }
private readonly Socket _remote = new Socket(SocketType.Stream, ProtocolType.Tcp);
private const string HTTP_CRLF = "\r\n";
private const string HTTP_CONNECT_TEMPLATE =
"CONNECT {0} HTTP/1.1" + HTTP_CRLF +
"Host: {0}" + HTTP_CRLF +
"Proxy-Connection: keep-alive" + HTTP_CRLF +
"User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36" + HTTP_CRLF +
"{1}" + // Proxy-Authorization if any
"" + HTTP_CRLF; // End with an empty line
private const string PROXY_AUTH_TEMPLATE = "Proxy-Authorization: Basic {0}" + HTTP_CRLF;
public void Shutdown(SocketShutdown how)
{
_remote.Shutdown(how);
}
public void Close()
{
_remote.Dispose();
}
private static readonly Regex HttpRespondHeaderRegex = new Regex(@"^(HTTP/1\.\d) (\d{3}) (.+)$", RegexOptions.Compiled);
private int _respondLineCount = 0;
private bool _established = false;
private bool OnLineRead(string line, object state)
{
this.Log().Debug(line);
if (_respondLineCount == 0)
{
var m = HttpRespondHeaderRegex.Match(line);
if (m.Success)
{
var resultCode = m.Groups[2].Value;
if ("200" != resultCode)
{
return true;
}
_established = true;
}
}
else
{
if (string.IsNullOrEmpty(line))
{
return true;
}
}
_respondLineCount++;
return false;
}
private NetworkCredential auth;
public async Task ConnectProxyAsync(EndPoint remoteEP, NetworkCredential auth = null, CancellationToken token = default)
{
ProxyEndPoint = remoteEP;
this.auth = auth;
await _remote.ConnectAsync(remoteEP);
_remote.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, true);
}
public async Task ConnectRemoteAsync(EndPoint destEndPoint, CancellationToken token = default)
{
DestEndPoint = destEndPoint;
String authInfo = "";
if (auth != null)
{
string authKey = Convert.ToBase64String(Encoding.UTF8.GetBytes(auth.UserName + ":" + auth.Password));
authInfo = string.Format(PROXY_AUTH_TEMPLATE, authKey);
}
string request = string.Format(HTTP_CONNECT_TEMPLATE, destEndPoint, authInfo);
var b = Encoding.UTF8.GetBytes(request);
await _remote.SendAsync(Encoding.UTF8.GetBytes(request), SocketFlags.None, token);
// start line read
LineReader reader = new LineReader(_remote, OnLineRead, (e, _) => throw e, (_1, _2, _3, _4) => { }, Encoding.UTF8, HTTP_CRLF, 1024, null);
await reader.Finished;
}
public async Task SendAsync(ReadOnlyMemory buffer, CancellationToken token = default)
{
return await _remote.SendAsync(buffer, SocketFlags.None, token);
}
public async Task ReceiveAsync(Memory buffer, CancellationToken token = default)
{
return await _remote.ReceiveAsync(buffer, SocketFlags.None, token);
}
}
}