default port matches endpoint; documentation improvements

src/cmd/add.go

@@ -18,7 +18,7 @@ type addCmdConfig struct {
 var addCmdArgs = addCmdConfig{
 	endpoint:  Endpoint,
 	outbound:  false,
-	port:      Port,
+	port:      USE_ENDPOINT_PORT,
 	keepalive: Keepalive,
 }
 

src/cmd/add_client.go

@@ -78,14 +78,18 @@ func (c addClientCmdConfig) Run() {
 	if len(baseConfigE2EE.GetAddresses()) == 1 {
 		disableV6 = true
 	}
+
+	if addArgs.port == USE_ENDPOINT_PORT {
+		addArgs.port = portFromEndpoint(addArgs.endpoint);
+	}
 
 	// Make new configs for client.
 	relayAddrs := []string{addresses.NextClientRelayAddr4.String() + "/32"}
 	if !disableV6 {
 		relayAddrs = append(relayAddrs, addresses.NextClientRelayAddr6.String()+"/128")
 	}
 	clientConfigRelay, err := peer.GetConfig(peer.ConfigArgs{
-		ListenPort: addCmdArgs.port,
+		ListenPort: addArgs.port,
 		Addresses:  relayAddrs,
 	})
 	check("failed to generate client relay config", err)

src/cmd/add_server.go

@@ -305,6 +305,11 @@ func (c addServerCmdConfig) Run() {
 		// Leaf server is the relay peer for the new server.
 		clientConfigRelay = leafServerConfigRelay
 	}
+
+	// Use a reasonable default for server listening ports
+	if addArgs.port == USE_ENDPOINT_PORT {
+		addArgs.port = Port;
+	}
 
 	if addArgs.port != Port {
 		err = serverConfigRelay.SetPort(addArgs.port)

src/cmd/configure.go

@@ -39,10 +39,10 @@ type configureCmdConfig struct {
 // Defaults for configure command.
 // See root command for shared defaults.
 var configureCmdArgs = configureCmdConfig{
-	allowedIPs:       []string{"0.0.0.0/32"},
+	allowedIPs:       []string{""},
 	endpoint:         Endpoint,
 	outbound:         false,
-	port:             Port,
+	port:             USE_ENDPOINT_PORT,
 	configFileRelay:  ConfigRelay,
 	configFileE2EE:   ConfigE2EE,
 	configFileServer: ConfigServer,
@@ -75,10 +75,10 @@ var configureCmd = &cobra.Command{
 func init() {
 	rootCmd.AddCommand(configureCmd)
 
-	configureCmd.Flags().StringSliceVarP(&configureCmdArgs.allowedIPs, "routes", "r", configureCmdArgs.allowedIPs, "CIDR IP ranges that will be routed through wiretap")
-	configureCmd.Flags().StringVarP(&configureCmdArgs.endpoint, "endpoint", "e", configureCmdArgs.endpoint, "socket address of wireguard listener that server will connect to (example \"1.2.3.4:51820\")")
-	configureCmd.Flags().BoolVar(&configureCmdArgs.outbound, "outbound", configureCmdArgs.outbound, "client will initiate handshake to server, set endpoint to server address")
-	configureCmd.Flags().IntVarP(&configureCmdArgs.port, "port", "p", configureCmdArgs.port, "port of local wireguard relay listener")
+	configureCmd.Flags().StringSliceVarP(&configureCmdArgs.allowedIPs, "routes", "r", configureCmdArgs.allowedIPs, "[REQUIRED] CIDR IP ranges that will be routed through wiretap (example \"10.0.0.1/24\")")
+	configureCmd.Flags().StringVarP(&configureCmdArgs.endpoint, "endpoint", "e", configureCmdArgs.endpoint, "[REQUIRED] IP:PORT (or [IP]:PORT for IPv6) of wireguard listener that server will connect to (example \"1.2.3.4:51820\")")
+	configureCmd.Flags().BoolVar(&configureCmdArgs.outbound, "outbound", configureCmdArgs.outbound, "client will initiate handshake to server; --endpoint now specifies server's listening socket instead of client's")
+	configureCmd.Flags().IntVarP(&configureCmdArgs.port, "port", "p", configureCmdArgs.port, "listener port for local wireguard relay; default is to use the same port specified by --endpoint")
 	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")
 	configureCmd.Flags().StringVarP(&configureCmdArgs.configFileServer, "server-output", "s", configureCmdArgs.configFileServer, "wiretap server config output filename")
@@ -159,6 +159,10 @@ func (c configureCmdConfig) Run() {
 	if !c.disableV6 {
 		clientE2EEAddrs = append(clientE2EEAddrs, c.clientAddr6E2EE)
 	}
+
+	if c.port == USE_ENDPOINT_PORT {
+		c.port = portFromEndpoint(c.endpoint);
+	}
 
 	clientConfigRelayArgs := peer.ConfigArgs{
 		ListenPort: c.port,

src/cmd/root.go

@@ -5,12 +5,16 @@ import (
 	"fmt"
 	"log"
 	"net/netip"
+	"net"
 	"os"
+	"strconv"
 
 	"github.com/fatih/color"
 	"github.com/spf13/cobra"
 )
 
+const USE_ENDPOINT_PORT = -1
+
 // Defaults shared by multiple commands.
 var (
 	Version            = "v0.0.0"
@@ -84,3 +88,13 @@ func check(message string, err error) {
 		log.Fatalf("%s: %v", message, err)
 	}
 }
+
+// Extract the port from the endpoint string 
+func portFromEndpoint(endpoint string) int {
+	_, strPort, err := net.SplitHostPort(endpoint)
+	check("cannot extract port from endpoint argument", err);
+
+	p, err := strconv.Atoi(strPort);
+	check("cannot extract port from endpoint argument", err);
+	return p;
+}

src/cmd/serve.go

@@ -229,7 +229,6 @@ func init() {
 				"public-e2ee",
 				"endpoint-relay",
 				"endpoint-e2ee",
-				"port",
 				"allowed",
 				"ipv4-relay",
 				"ipv6-relay",