main.go

package main

import (
	"crypto/tls"
	"github.com/patrickmn/go-cache"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"log"
	"net/http"
	"os"
	"strconv"
	"time"
)

var cmd = &cobra.Command{
	Use:	"rdpgw",
	Long:	"Remote Desktop Gateway",
}

var (
	port		int
	certFile	string
	keyFile		string

	configFile	string
)

var tokens = cache.New(time.Minute *5, 10*time.Minute)

func main() {
	cmd.PersistentFlags().IntVarP(&port, "port", "p", 443, "port to listen on for incoming connection")
	cmd.PersistentFlags().StringVarP(&certFile, "certfile", "", "server.pem", "public key certificate file")
	cmd.PersistentFlags().StringVarP(&keyFile, "keyfile", "", "key.pem", "private key file")
	cmd.PersistentFlags().StringVarP(&configFile, "conf", "c", "rdpgw.yaml",  "config file (json, yaml, ini)")

	viper.BindPFlag("port", cmd.PersistentFlags().Lookup("port"))
	viper.BindPFlag("certfile", cmd.PersistentFlags().Lookup("certfile"))
	viper.BindPFlag("keyfile", cmd.PersistentFlags().Lookup("keyfile"))

	viper.SetConfigFile(configFile)
	viper.AddConfigPath(".")
	viper.SetEnvPrefix("RDPGW")
	viper.AutomaticEnv()

	err := viper.ReadInConfig()
	if err != nil {
		log.Printf("No config file found. Using defaults")
	}

	if certFile == "" || keyFile == "" {
		log.Fatal("Both certfile and keyfile need to be specified")
	}

	//mux := http.NewServeMux()
	//mux.HandleFunc("*", HelloServer)

	log.Printf("Starting remote desktop gateway server")
	cfg := &tls.Config{}
	tlsDebug := os.Getenv("SSLKEYLOGFILE")
	if tlsDebug != "" {
		w, err := os.OpenFile(tlsDebug, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
		if err != nil {
			log.Fatalf("Cannot open key log file %s for writing %s", tlsDebug, err)
		}
		log.Printf("Key log file set to: %s", tlsDebug)
		cfg.KeyLogWriter = w
	}
	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
	if err != nil {
		log.Fatal(err)
	}
	cfg.Certificates = append(cfg.Certificates, cert)
	server := http.Server{
		Addr:      ":" + strconv.Itoa(port),
		TLSConfig: cfg,
		TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)), // disable http2
	}

	http.HandleFunc("/remoteDesktopGateway/", handleGatewayProtocol)
	http.HandleFunc("/connect", handleRdpDownload)
	http.Handle("/metrics", promhttp.Handler())

	prometheus.MustRegister(connectionCache)
	prometheus.MustRegister(legacyConnections)
	prometheus.MustRegister(websocketConnections)

	err = server.ListenAndServeTLS("", "")
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}