From 7bfa331758a570dc2c47187c0dbd225cf200ae16 Mon Sep 17 00:00:00 2001
From: Martin Dosch <martin@mdosch.de>
Date: Sat, 13 Jan 2024 14:05:35 +0100
Subject: [PATCH] Add support for SOCKS5 proxies.

---
 go.mod  |  5 ++++-
 go.sum  |  2 ++
 xmpp.go | 38 ++++++++++++++++++++++++++------------
 3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/go.mod b/go.mod
index d8ce01b..dde017b 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,7 @@ module github.com/xmppo/go-xmpp
 
 go 1.21.5
 
-require golang.org/x/crypto v0.18.0
+require (
+	golang.org/x/crypto v0.18.0
+	golang.org/x/net v0.10.0
+)
diff --git a/go.sum b/go.sum
index 4dda6b7..959da46 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,4 @@
 golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
+golang.org/x/net v0.10.0 h1:X2//UzNDwYmtCLn7To6G58Wr6f5ahEAQgKNzv9Y951M=
+golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
diff --git a/xmpp.go b/xmpp.go
index c009c7f..4dd161a 100644
--- a/xmpp.go
+++ b/xmpp.go
@@ -41,6 +41,7 @@ import (
 	"time"
 
 	"golang.org/x/crypto/pbkdf2"
+	"golang.org/x/net/proxy"
 )
 
 const (
@@ -103,12 +104,12 @@ func connect(host, user, passwd string, timeout time.Duration) (net.Conn, error)
 		addr += ":5222"
 	}
 
-	proxy := os.Getenv("HTTP_PROXY")
-	if proxy == "" {
-		proxy = os.Getenv("http_proxy")
+	http_proxy := os.Getenv("HTTP_PROXY")
+	if http_proxy == "" {
+		http_proxy = os.Getenv("http_proxy")
 	}
 	// test for no proxy, takes a comma separated list with substrings to match
-	if proxy != "" {
+	if http_proxy != "" {
 		noproxy := os.Getenv("NO_PROXY")
 		if noproxy == "" {
 			noproxy = os.Getenv("no_proxy")
@@ -117,25 +118,38 @@ func connect(host, user, passwd string, timeout time.Duration) (net.Conn, error)
 			nplist := strings.Split(noproxy, ",")
 			for _, s := range nplist {
 				if containsIgnoreCase(addr, s) {
-					proxy = ""
+					http_proxy = ""
 					break
 				}
 			}
 		}
 	}
-	if proxy != "" {
-		url, err := url.Parse(proxy)
+	socks5Target, socks5 := strings.CutPrefix(http_proxy, "socks5://")
+	if http_proxy != "" && !socks5 {
+		url, err := url.Parse(http_proxy)
 		if err == nil {
 			addr = url.Host
 		}
 	}
-
-	c, err := net.DialTimeout("tcp", addr, timeout)
-	if err != nil {
-		return nil, err
+	var c net.Conn
+	var err error
+	if socks5 {
+		dialer, err := proxy.SOCKS5("tcp", socks5Target, nil, nil)
+		if err != nil {
+			return nil, err
+		}
+		c, err = dialer.Dial("tcp", addr)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		c, err = net.DialTimeout("tcp", addr, timeout)
+		if err != nil {
+			return nil, err
+		}
 	}
 
-	if proxy != "" {
+	if http_proxy != "" && !socks5 {
 		fmt.Fprintf(c, "CONNECT %s HTTP/1.1\r\n", host)
 		fmt.Fprintf(c, "Host: %s\r\n", host)
 		fmt.Fprintf(c, "\r\n")