1// Copyright 2012, Hailiang Wang. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5/*
6Package socks implements a SOCKS (SOCKS4, SOCKS4A and SOCKS5) proxy client.
7
8A complete example using this package:
9	package main
10
11	import (
12		"h12.io/socks"
13		"fmt"
14		"net/http"
15		"io/ioutil"
16	)
17
18	func main() {
19		dialSocksProxy := socks.Dial("socks5://127.0.0.1:1080?timeout=5s")
20		tr := &http.Transport{Dial: dialSocksProxy}
21		httpClient := &http.Client{Transport: tr}
22
23		bodyText, err := TestHttpsGet(httpClient, "https://h12.io/about")
24		if err != nil {
25			fmt.Println(err.Error())
26		}
27		fmt.Print(bodyText)
28	}
29
30	func TestHttpsGet(c *http.Client, url string) (bodyText string, err error) {
31		resp, err := c.Get(url)
32		if err != nil { return }
33		defer resp.Body.Close()
34
35		body, err := ioutil.ReadAll(resp.Body)
36		if err != nil { return }
37		bodyText = string(body)
38		return
39	}
40*/
41package socks // import "h12.io/socks"
42
43import (
44	"fmt"
45	"net"
46)
47
48// Constants to choose which version of SOCKS protocol to use.
49const (
50	SOCKS4 = iota
51	SOCKS4A
52	SOCKS5
53)
54
55// Dial returns the dial function to be used in http.Transport object.
56// Argument proxyURI should be in the format: "socks5://user:password@127.0.0.1:1080?timeout=5s".
57// The protocol could be socks5, socks4 and socks4a.
58func Dial(proxyURI string) func(string, string) (net.Conn, error) {
59	cfg, err := parse(proxyURI)
60	if err != nil {
61		return dialError(err)
62	}
63	return cfg.dialFunc()
64}
65
66// DialSocksProxy returns the dial function to be used in http.Transport object.
67// Argument socksType should be one of SOCKS4, SOCKS4A and SOCKS5.
68// Argument proxy should be in this format "127.0.0.1:1080".
69func DialSocksProxy(socksType int, proxy string) func(string, string) (net.Conn, error) {
70	return (&config{Proto: socksType, Host: proxy}).dialFunc()
71}
72
73func (c *config) dialFunc() func(string, string) (net.Conn, error) {
74	switch c.Proto {
75	case SOCKS5:
76		return func(_, targetAddr string) (conn net.Conn, err error) {
77			return c.dialSocks5(targetAddr)
78		}
79	case SOCKS4, SOCKS4A:
80		return func(_, targetAddr string) (conn net.Conn, err error) {
81			return c.dialSocks4(targetAddr)
82		}
83	}
84	return dialError(fmt.Errorf("unknown SOCKS protocol %v", c.Proto))
85}
86
87func dialError(err error) func(string, string) (net.Conn, error) {
88	return func(_, _ string) (net.Conn, error) {
89		return nil, err
90	}
91}
92