tls.go

package transport

import (
	"crypto/tls"
	"fmt"
	"net"
	"time"
)

func TLSDialer(tlscfg *tls.Config, timeout time.Duration, forward Dialer) Dialer {
	if tlscfg == nil {
		return forward
	}

	return DialerFunc(func(network, address string) (net.Conn, error) {
		switch network {
		case "tcp", "tcp4", "tcp6":
		default:
			return nil, fmt.Errorf("unsupported network type %v", network)
		}

		socket, err := forward.Dial(network, address)
		if err != nil {
			return nil, err
		}

		host, _, err := net.SplitHostPort(address)
		if err != nil {
			return nil, err
		}

		tlscfg.ServerName = host
		conn := tls.Client(socket, tlscfg)
		if err := conn.SetDeadline(time.Now().Add(timeout)); err != nil {
			_ = conn.Close()
			return nil, err
		}
		if err := conn.Handshake(); err != nil {
			_ = conn.Close()
			return nil, err
		}

		return conn, nil
	})
}