fix: add DNS fallback using 8.8.8.8 for Android/Termux

Android/Termux /etc/resolv.conf often points to [::1]:53 (localhost)
with no DNS server running, causing Go's internal resolver to fail.
Added dialWS() which tries system DNS first, then falls back to a
custom resolver using 8.8.8.8:53 directly.

Author: bgwastu

bridge/main.go

@@ -2,10 +2,13 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -322,9 +325,71 @@ func readCommands(wsc *wsConn, dot string) bool {
 	}
 }
 
-func dialAndRun(wsURL, code, connectURL string, quit <-chan struct{}) (string, bool) {
+// dialWS connects to a WebSocket URL, falling back to 8.8.8.8 for DNS
+// if the system resolver fails (common on Android/Termux where /etc/resolv.conf
+// points to a non-existent localhost DNS server).
+func dialWS(wsURL string) (*websocket.Conn, *http.Response, error) {
+	u, err := url.Parse(wsURL)
+	if err != nil {
+		return nil, nil, err
+	}
+
 	dialer := websocket.Dialer{HandshakeTimeout: 15 * time.Second}
 	conn, resp, err := dialer.Dial(wsURL, http.Header{})
+	if err == nil {
+		return conn, resp, nil
+	}
+
+	// Check if it's a DNS error by trying to resolve with a fallback DNS
+	hostname := u.Hostname()
+	port := u.Port()
+	if port == "" {
+		if u.Scheme == "wss" {
+			port = "443"
+		} else {
+			port = "80"
+		}
+	}
+
+	// Try to resolve using the system DNS first (may have failed)
+	ips, lookupErr := net.DefaultResolver.LookupHost(context.Background(), hostname)
+	if lookupErr != nil {
+		// System DNS failed — try Google DNS (8.8.8.8) directly
+		altResolver := &net.Resolver{
+			PreferGo: true,
+			Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+				d := net.Dialer{Timeout: 5 * time.Second}
+				return d.DialContext(ctx, "udp", "8.8.8.8:53")
+			},
+		}
+		ips, lookupErr = altResolver.LookupHost(context.Background(), hostname)
+		if lookupErr != nil || len(ips) == 0 {
+			return conn, resp, fmt.Errorf("%w (DNS: also tried 8.8.8.8: %v)", err, lookupErr)
+		}
+	}
+
+	// Try each resolved IP with the WebSocket dialer
+	for _, ip := range ips {
+		directURL := wsURL
+		if strings.HasPrefix(wsURL, "ws://") {
+			directURL = fmt.Sprintf("ws://%s:%s", ip, port)
+		} else if strings.HasPrefix(wsURL, "wss://") {
+			directURL = fmt.Sprintf("wss://%s:%s", ip, port)
+		}
+
+		headers := http.Header{}
+		headers.Set("Host", hostname)
+		conn, resp, err = dialer.Dial(directURL, headers)
+		if err == nil {
+			return conn, resp, nil
+		}
+	}
+
+	return conn, resp, err
+}
+
+func dialAndRun(wsURL, code, connectURL string, quit <-chan struct{}) (string, bool) {
+	conn, resp, err := dialWS(wsURL)
 	if err != nil {
 		if resp != nil {
 			_, _ = io.Copy(io.Discard, resp.Body)