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/*
* Copyright (c) 2014, Yawning Angel <yawning at torproject dot org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package main
import (
"bufio"
"fmt"
"net"
"net/http"
"net/http/httputil"
"net/url"
"time"
"golang.org/x/net/proxy"
)
// httpProxy is a HTTP connect proxy.
type httpProxy struct {
hostPort string
haveAuth bool
username string
password string
forward proxy.Dialer
}
func newHTTP(uri *url.URL, forward proxy.Dialer) (proxy.Dialer, error) {
s := new(httpProxy)
s.hostPort = uri.Host
s.forward = forward
if uri.User != nil {
s.haveAuth = true
s.username = uri.User.Username()
s.password, _ = uri.User.Password()
}
return s, nil
}
func (s *httpProxy) Dial(network, addr string) (net.Conn, error) {
// Dial and create the http client connection.
c, err := s.forward.Dial("tcp", s.hostPort)
if err != nil {
return nil, err
}
conn := new(httpConn)
conn.httpConn = httputil.NewClientConn(c, nil)
conn.remoteAddr, err = net.ResolveTCPAddr(network, addr)
if err != nil {
conn.httpConn.Close()
return nil, err
}
// HACK HACK HACK HACK. http.ReadRequest also does this.
reqURL, err := url.Parse("http://" + addr)
if err != nil {
conn.httpConn.Close()
return nil, err
}
reqURL.Scheme = ""
req, err := http.NewRequest("CONNECT", reqURL.String(), nil)
if err != nil {
conn.httpConn.Close()
return nil, err
}
req.Close = false
if s.haveAuth {
req.SetBasicAuth(s.username, s.password)
}
req.Header.Set("User-Agent", "")
resp, err := conn.httpConn.Do(req)
if err != nil && err != httputil.ErrPersistEOF {
conn.httpConn.Close()
return nil, err
}
if resp.StatusCode != 200 {
conn.httpConn.Close()
return nil, fmt.Errorf("proxy error: %s", resp.Status)
}
conn.hijackedConn, conn.staleReader = conn.httpConn.Hijack()
return conn, nil
}
type httpConn struct {
remoteAddr *net.TCPAddr
httpConn *httputil.ClientConn
hijackedConn net.Conn
staleReader *bufio.Reader
}
func (c *httpConn) Read(b []byte) (int, error) {
if c.staleReader != nil {
if c.staleReader.Buffered() > 0 {
return c.staleReader.Read(b)
}
c.staleReader = nil
}
return c.hijackedConn.Read(b)
}
func (c *httpConn) Write(b []byte) (int, error) {
return c.hijackedConn.Write(b)
}
func (c *httpConn) Close() error {
return c.hijackedConn.Close()
}
func (c *httpConn) LocalAddr() net.Addr {
return c.hijackedConn.LocalAddr()
}
func (c *httpConn) RemoteAddr() net.Addr {
return c.remoteAddr
}
func (c *httpConn) SetDeadline(t time.Time) error {
return c.hijackedConn.SetDeadline(t)
}
func (c *httpConn) SetReadDeadline(t time.Time) error {
return c.hijackedConn.SetReadDeadline(t)
}
func (c *httpConn) SetWriteDeadline(t time.Time) error {
return c.hijackedConn.SetWriteDeadline(t)
}
func init() {
proxy.RegisterDialerType("http", newHTTP)
}
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