feat(transport/websocket): support SOCKS proxy with ws(s) (#3137)

Author: MarcoPolo

p2p/transport/websocket/websocket.go

@@ -160,6 +160,8 @@ func (t *WebsocketTransport) Resolve(_ context.Context, maddr ma.Multiaddr) ([]m
 	return []ma.Multiaddr{parsed.toMultiaddr()}, nil
 }
 
+// Dial will dial the given multiaddr and expect the given peer. If an
+// HTTPS_PROXY env is set, it will use that for the dial out.
 func (t *WebsocketTransport) Dial(ctx context.Context, raddr ma.Multiaddr, p peer.ID) (transport.CapableConn, error) {
 	connScope, err := t.rcmgr.OpenConnection(network.DirOutbound, true, raddr)
 	if err != nil {
@@ -191,7 +193,11 @@ func (t *WebsocketTransport) maDial(ctx context.Context, raddr ma.Multiaddr) (ma
 		return nil, err
 	}
 	isWss := wsurl.Scheme == "wss"
-	dialer := ws.Dialer{HandshakeTimeout: 30 * time.Second}
+	dialer := ws.Dialer{
+		HandshakeTimeout: 30 * time.Second,
+		// Inherit the default proxy behavior
+		Proxy: ws.DefaultDialer.Proxy,
+	}
 	if isWss {
 		sni := ""
 		sni, err = raddr.ValueForProtocol(ma.P_SNI)
@@ -203,17 +209,23 @@ func (t *WebsocketTransport) maDial(ctx context.Context, raddr ma.Multiaddr) (ma
 			copytlsClientConf := t.tlsClientConf.Clone()
 			copytlsClientConf.ServerName = sni
 			dialer.TLSClientConfig = copytlsClientConf
-			ipAddr := wsurl.Host
-			// Setting the NetDial because we already have the resolved IP address, so we don't want to do another resolution.
+			ipPortAddr := wsurl.Host
 			// We set the `.Host` to the sni field so that the host header gets properly set.
+			wsurl.Host = sni + ":" + wsurl.Port()
+			// Setting the NetDial because we already have the resolved IP address, so we can avoid another resolution.
 			dialer.NetDial = func(network, address string) (net.Conn, error) {
-				tcpAddr, err := net.ResolveTCPAddr(network, ipAddr)
+				var tcpAddr *net.TCPAddr
+				var err error
+				if address == wsurl.Host {
+					tcpAddr, err = net.ResolveTCPAddr(network, ipPortAddr) // Use our already resolved IP address
+				} else {
+					tcpAddr, err = net.ResolveTCPAddr(network, address)
+				}
 				if err != nil {
 					return nil, err
 				}
 				return net.DialTCP("tcp", nil, tcpAddr)
 			}
-			wsurl.Host = sni + ":" + wsurl.Port()
 		} else {
 			dialer.TLSClientConfig = t.tlsClientConf
 		}

p2p/transport/websocket/websocket_test.go

@@ -1,6 +1,7 @@
 package websocket
 
 import (
+	"bytes"
 	"context"
 	"crypto/ecdsa"
 	"crypto/elliptic"
@@ -15,10 +16,12 @@ import (
 	"math/big"
 	"net"
 	"net/http"
+	"net/url"
 	"strings"
 	"testing"
 	"time"
 
+	gws "github.com/gorilla/websocket"
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -548,3 +551,75 @@ func TestResolveMultiaddr(t *testing.T) {
 		})
 	}
 }
+
+func TestSocksProxy(t *testing.T) {
+	testCases := []string{
+		"/ip4/1.2.3.4/tcp/1/ws",                     // No TLS
+		"/ip4/1.2.3.4/tcp/1/tls/ws",                 // TLS no SNI
+		"/ip4/1.2.3.4/tcp/1/tls/sni/example.com/ws", // TLS with an SNI
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc, func(t *testing.T) {
+			proxyServer, err := net.Listen("tcp", "127.0.0.1:0")
+			require.NoError(t, err)
+			proxyServerErr := make(chan error, 1)
+
+			go func() {
+				defer proxyServer.Close()
+				c, err := proxyServer.Accept()
+				if err != nil {
+					proxyServerErr <- err
+					return
+				}
+				defer c.Close()
+
+				req := [32]byte{}
+				_, err = io.ReadFull(c, req[:3])
+				if err != nil {
+					proxyServerErr <- err
+					return
+				}
+
+				// Handshake a SOCKS5 client: https://www.rfc-editor.org/rfc/rfc1928.html#section-3
+				if !bytes.Equal([]byte{0x05, 0x01, 0x00}, req[:3]) {
+					t.Log("expected SOCKS5 connect request")
+					proxyServerErr <- err
+					return
+				}
+				_, err = c.Write([]byte{0x05, 0x00})
+				if err != nil {
+					proxyServerErr <- err
+					return
+				}
+
+				proxyServerErr <- nil
+			}()
+
+			orig := gws.DefaultDialer.Proxy
+			defer func() { gws.DefaultDialer.Proxy = orig }()
+
+			proxyUrl, err := url.Parse("socks5://" + proxyServer.Addr().String())
+			require.NoError(t, err)
+			gws.DefaultDialer.Proxy = http.ProxyURL(proxyUrl)
+
+			tlsConfig := &tls.Config{InsecureSkipVerify: true} // Our test server doesn't have a cert signed by a CA
+			_, u := newSecureUpgrader(t)
+			tpt, err := New(u, &network.NullResourceManager{}, nil, WithTLSClientConfig(tlsConfig))
+			require.NoError(t, err)
+
+			// This can be any wss address. We aren't actually going to dial it.
+			maToDial := ma.StringCast(tc)
+			_, err = tpt.Dial(context.Background(), maToDial, "")
+			require.ErrorContains(t, err, "failed to read connect reply from SOCKS5 proxy", "This should error as we don't have a real socks server")
+
+			select {
+			case <-time.After(1 * time.Second):
+			case err := <-proxyServerErr:
+				if err != nil {
+					t.Fatal(err)
+				}
+			}
+		})
+	}
+}