adding PSK support

src/cmd/configure.go

@@ -38,6 +38,7 @@ type configureCmdConfig struct {
 	mtu              int
 	disableV6        bool
 	localhostIP      string
+	generatePSK		 bool
 }
 
 // Defaults for configure command.
@@ -66,6 +67,7 @@ var configureCmdArgs = configureCmdConfig{
 	mtu:              MTU,
 	disableV6:        false,
 	localhostIP:      "",
+	generatePSK:	  false,
 }
 
 // configureCmd represents the configure command.
@@ -89,6 +91,7 @@ func init() {
 	configureCmd.Flags().IntVarP(&configureCmdArgs.sport, "sport", "S", configureCmdArgs.sport, "listener port for server wireguard relay. Default is to copy the --outbound-endpoint port, or fallback to 51820")
 	configureCmd.Flags().StringVarP(&configureCmdArgs.nickname, "nickname", "n", configureCmdArgs.nickname, "Server nickname to display in 'status' command")
 	configureCmd.Flags().StringVarP(&configureCmdArgs.localhostIP, "localhost-ip", "i", configureCmdArgs.localhostIP, "[EXPERIMENTAL] Redirect wiretap packets destined for this IPv4 address to server's localhost")
+	configureCmd.Flags().BoolVarP(&configureCmdArgs.generatePSK, "PSK", "K", configureCmdArgs.generatePSK, "generates a preshared key")
 
 	configureCmd.Flags().StringVarP(&configureCmdArgs.configFileRelay, "relay-output", "", configureCmdArgs.configFileRelay, "wireguard relay config output filename")
 	configureCmd.Flags().StringVarP(&configureCmdArgs.configFileE2EE, "e2ee-output", "", configureCmdArgs.configFileE2EE, "wireguard E2EE config output filename")
@@ -223,6 +226,15 @@ func (c configureCmdConfig) Run() {
 		Peers: []peer.PeerConfigArgs{
 			{
 				PublicKey: serverConfigRelay.GetPublicKey(),
+				PresharedKey: func() string {
+					if c.generatePSK {
+						err = serverConfigRelay.GenPresharedKey()
+						check("failed to generate preshared key", err)
+						return serverConfigRelay.GetPresharedKey()
+					} else {
+						return ""
+					}
+				}(),
 				AllowedIPs: func() []string {
 					if c.simple {
 						return c.allowedIPs

src/cmd/serve.go

@@ -165,6 +165,7 @@ func init() {
 	// Deprecated flags, kept for backwards compatibility.
 	cmd.Flags().StringP("private-relay", "", "", "wireguard private key for relay interface")
 	cmd.Flags().StringP("public-relay", "", "", "wireguard public key of remote peer for relay interface")
+	cmd.Flags().StringP("preshared-relay", "", "", "wireguard preshared key of remote peer for relay interface")
 	cmd.Flags().StringP("private-e2ee", "", "", "wireguard private key for E2EE interface")
 	cmd.Flags().StringP("public-e2ee", "", "", "wireguard public key of remote peer for E2EE interface")
 	cmd.Flags().StringP("endpoint-relay", "", wiretapDefault.endpointRelay, "socket address of remote peer that server will connect to (example \"1.2.3.4:51820\")")
@@ -189,6 +190,8 @@ func init() {
 
 	err = viper.BindPFlag("Relay.Peer.publickey", cmd.Flags().Lookup("public-relay"))
 	check("error binding flag to viper", err)
+	err = viper.BindPFlag("Relay.Peer.presharedkey", cmd.Flags().Lookup("preshared-relay"))
+	check("error binding flag to viper", err)
 	err = viper.BindPFlag("Relay.Peer.endpoint", cmd.Flags().Lookup("endpoint-relay"))
 	check("error binding flag to viper", err)
 	err = viper.BindPFlag("Relay.Peer.allowed", cmd.Flags().Lookup("allowed"))
@@ -239,6 +242,7 @@ func init() {
 				"ipv6-e2ee-client",
 				"private-relay",
 				"public-relay",
+				"preshared-relay",
 				"private-e2ee",
 				"public-e2ee",
 				"endpoint-relay",
@@ -370,6 +374,13 @@ func (c serveCmdConfig) Run() {
 						return 0
 					}
 				}(),
+				PresharedKey: func() string {
+					if len(viper.GetString("Relay.Peer.presharedkey")) > 0 {
+						return viper.GetString("Relay.Peer.presharedkey")
+					} else {
+						return ""
+					}
+				}(),
 				AllowedIPs: aips,
 			},
 		},

src/peer/config.go

@@ -19,6 +19,7 @@ type Config struct {
 	peers       []PeerConfig
 	addresses   []net.IPNet
 	localhostIP string
+	presharedKey *wgtypes.Key
 }
 
 type configJSON struct {
@@ -27,6 +28,7 @@ type configJSON struct {
 	Peers       []PeerConfig
 	Addresses   []net.IPNet
 	LocalhostIP string
+	PresharedKey *wgtypes.Key
 }
 
 type ConfigArgs struct {
@@ -38,6 +40,7 @@ type ConfigArgs struct {
 	Peers        []PeerConfigArgs
 	Addresses    []string
 	LocalhostIP  string
+	PresharedKey string
 }
 
 type Shell uint
@@ -193,6 +196,8 @@ func ParseConfig(filename string) (c Config, err error) {
 					err = newPeer.SetAllowedIPs(strings.Split(value, ","))
 				case "publickey":
 					err = newPeer.SetPublicKey(value)
+				case "presharedkey":
+					err = newPeer.SetPresharedKey(value)
 				case "persistentkeepalive":
 					keepalive, e := strconv.Atoi(value)
 					if e != nil {
@@ -233,6 +238,7 @@ func (c *Config) MarshalJSON() ([]byte, error) {
 		c.peers,
 		c.addresses,
 		c.localhostIP,
+		c.presharedKey,
 	})
 }
 
@@ -248,6 +254,7 @@ func (c *Config) UnmarshalJSON(b []byte) error {
 	c.peers = tmp.Peers
 	c.addresses = tmp.Addresses
 	c.localhostIP = tmp.LocalhostIP
+	c.presharedKey = tmp.PresharedKey
 
 	return nil
 }
@@ -266,6 +273,23 @@ func (c *Config) GetPrivateKey() string {
 	return c.config.PrivateKey.String()
 }
 
+func (c* Config) GenPresharedKey() error {
+	key, err := wgtypes.GenerateKey()
+	if err != nil {
+		return err
+	}
+	c.presharedKey = &key
+	return nil
+}
+
+func (c* Config) GetPresharedKey() string {
+	if c.presharedKey != nil {
+		return c.presharedKey.String()
+	} else {
+		return ""
+	}
+}
+
 func (c *Config) SetPort(port int) error {
 	if port < 1 || port > 65535 {
 		return errors.New("invalid port")
@@ -440,6 +464,9 @@ func (c *Config) AsShareableFile() string {
 
 	s.WriteString("[Peer]\n")
 	s.WriteString(fmt.Sprintf("PublicKey = %s\n", c.config.PrivateKey.PublicKey().String()))
+	if c.presharedKey != nil {
+		s.WriteString(fmt.Sprintf("PresharedKey = %s\n", c.presharedKey.String()))
+	}
 	s.WriteString("AllowedIPs = 0.0.0.0/32\n")
 
 	return s.String()
@@ -488,6 +515,11 @@ func CreateServerCommand(relayConfig Config, e2eeConfig Config, shell Shell, sim
 	// Relay Peer.
 	keys = append(keys, "WIRETAP_RELAY_PEER_PUBLICKEY")
 	vals = append(vals, relayConfig.GetPeerPublicKey(0))
+
+	if relayConfig.presharedKey != nil {
+		keys = append(keys, "WIRETAP_RELAY_PEER_PRESHAREDKEY")
+		vals = append(vals, relayConfig.GetPresharedKey())
+	}
 
 	if len(relayConfig.peers) > 0 && len(relayConfig.peers[0].config.AllowedIPs) > 0 {
 		keys = append(keys, "WIRETAP_RELAY_PEER_ALLOWED")
@@ -588,6 +620,9 @@ func CreateServerFile(relayConfig Config, e2eeConfig Config, simple bool) string
 	}
 
 	s.WriteString(fmt.Sprintf("PublicKey = %s\n", relayConfig.GetPeerPublicKey(0)))
+	if relayConfig.presharedKey != nil {
+		s.WriteString(fmt.Sprintf("PresharedKey = %s\n", relayConfig.GetPresharedKey()))
+	}
 	if len(relayConfig.GetPeerEndpoint(0)) > 0 {
 		s.WriteString(fmt.Sprintf("Endpoint = %s\n", relayConfig.GetPeerEndpoint(0)))
 	}

src/peer/peer_config.go

@@ -277,6 +277,10 @@ func (p *PeerConfig) AsFile() string {
 
 	s.WriteString(fmt.Sprintf("PublicKey = %s\n", p.config.PublicKey.String()))
 
+	if p.config.PresharedKey != nil {
+		s.WriteString(fmt.Sprintf("PresharedKey = %s\n", p.config.PresharedKey.String()))
+	}
+
 	ips := []string{}
 	for _, a := range p.config.AllowedIPs {
 		ips = append(ips, a.String())
@@ -301,6 +305,9 @@ func (p *PeerConfig) AsIPC() string {
 	var s strings.Builder
 
 	s.WriteString(fmt.Sprintf("public_key=%s\n", hex.EncodeToString(p.config.PublicKey[:])))
+	if p.config.PresharedKey != nil {
+		s.WriteString(fmt.Sprintf("preshared_key=%s\n", hex.EncodeToString(p.config.PresharedKey[:])))
+	}
 	if p.config.Endpoint != nil {
 		s.WriteString(fmt.Sprintf("endpoint=%s\n", p.config.Endpoint.String()))
 	}