Allow tls/ssl connections over proxy dialer

[tarunKoyalwar]

Description

Context

Most optimization related features of fastdialer like happy eyeballs algorithm, handling permanent errors, optimized for hostnames to rank ips and parallel dial etc

currently when proxyDialer is specified ( socks5 proxy dialer) via Options, it is used for creating non-tls connections as we can see here

fastdialer/fastdialer/dialer_private.go

Lines 303 to 327 in e12186b

	if d.proxyDialer != nil {
	dialer := *d.proxyDialer
	// timeout not working for socks5 proxy dialer
	// tying to handle it here
	connectionCh := make(chan net.Conn, 1)
	errCh := make(chan error, 1)
	go func() {
	conn, err = dialer.Dial(opts.network, hostPort)
	if err != nil {
	errCh <- err
	return
	}
	connectionCh <- conn
	}()
	// using timer as time.After is not recovered gy GC
	dialerTime := time.NewTimer(d.options.DialerTimeout)
	defer dialerTime.Stop()
	select {
	case <-dialerTime.C:
	return nil, fmt.Errorf("timeout after %v", d.options.DialerTimeout)
	case conn = <-connectionCh:
	case err = <-errCh:
	}
	err = d.handleDialError(err, opts)
	} else {

but when the network type is tls we skip using proxy dialer and fallback to using net.Dialer (

fastdialer/fastdialer/dialer_private.go

Lines 156 to 184 in e12186b

	var finalDialer l4dialer = d.dialer
	if dw == nil && hostname != "" && len(IPS) > 0 && d.proxyDialer == nil {
	// only cache it if below conditions are met
	// 1. it is already not present
	// 2. it is a domain and not ip
	// 3. it has at least 1 valid ip
	// 4. proxy dialer is not set
	dw, err = utils.NewDialWrap(d.dialer, IPS, opts.network, opts.address, opts.port)
	if err != nil {
	return nil, errkit.Wrap(err, "could not create dialwrap")
	}
	if err = d.dialCache.Set(opts.connHash(), dw); err != nil {
	return nil, errkit.Wrap(err, "could not set dialwrap")
	}
	}
	if dw != nil {
	finalDialer = dw
	// when using dw ip , network , port etc are preset
	// so get any one of them to avoid breaking further logic
	ip, port := dw.Address()
	opts.ips = []string{ip}
	opts.port = port
	// also set hostname by parsing it from address
	hostname, _, _ = net.SplitHostPort(opts.address)
	opts.hostname = hostname
	}

)

Possible Changes

• modify the utils.DialWrap implementation to accept ( proxyDialer ) as input instead of just net.Dial
• modify dialer_private.go to simply override l4Dialer with proxyDialer

Note: when modifying utils.DialWrap to accept proxyDialer , some options like happy eyeballs and other setting like multipath etc might not be possible and should be treated as no-op

Follow-up

• remove dialTLSContext override in nuclei where we override DialTLSContext to use net.Dialer when socks5 proxy is being used

[tarunKoyalwar]

Since socks5 is a important component now , we can maybe add some integration tests to verify socks5 is being used and networkpolicy related config when socks5 proxy is set