initial integration for bounded dialer in static mode

main.go

@@ -72,6 +72,7 @@ type CLIArgs struct {
 	passwdCost        int
 	positionalArgs    []string
 	proxy             []string
+	sourceIPHints     []net.IP
 }
 
 func parse_args() CLIArgs {
@@ -101,6 +102,14 @@ func parse_args() CLIArgs {
 		args.proxy = append(args.proxy, p)
 		return nil
 	})
+	flag.Func("ip-hints", "a comma-separated list of addresses to use on dial attempts. Example: \"10.0.0.1,fe80::2,0.0.0.0,::\"", func(p string) error {
+		list, err := parseIPList(p)
+		if err != nil {
+			return err
+		}
+		args.sourceIPHints = list
+		return nil
+	})
 	flag.Parse()
 	args.positionalArgs = flag.Args()
 	return args
@@ -146,7 +155,7 @@ func run() int {
 	}
 	defer auth.Stop()
 
-	var dialer Dialer = new(net.Dialer)
+	var dialer Dialer = NewBoundDialer(new(net.Dialer), args.sourceIPHints)
 	for _, proxyURL := range args.proxy {
 		newDialer, err := proxyDialerFromURL(proxyURL, dialer)
 		if err != nil {

utils.go

@@ -369,3 +369,19 @@ func maybeWrapWithContextDialer(d Dialer) ContextDialer {
 	}
 	return wrappedDialer{d}
 }
+
+func parseIPList(list string) ([]net.IP, error) {
+	res := make([]net.IP, 0)
+	for _, elem := range strings.Split(list, ",") {
+		elem = strings.TrimSpace(elem)
+		if len(elem) == 0 {
+			continue
+		}
+		if parsed := net.ParseIP(elem); parsed == nil {
+			return nil, fmt.Errorf("unable to parse IP address %q", elem)
+		} else {
+			res = append(res, parsed)
+		}
+	}
+	return res, nil
+}