e2e: Support testing on MacOS without requiring firewall exceptions (a…

…va-labs#1613)

config/config.go

@@ -603,18 +603,22 @@ func getIPConfig(v *viper.Viper) (node.IPConfig, error) {
 		return node.IPConfig{}, fmt.Errorf("only one of --%s and --%s can be given", PublicIPKey, PublicIPResolutionServiceKey)
 	}
 
+	// Define default configuration
+	ipConfig := node.IPConfig{
+		IPUpdater:        dynamicip.NewNoUpdater(),
+		IPResolutionFreq: ipResolutionFreq,
+		Nat:              nat.NewNoRouter(),
+		ListenHost:       v.GetString(StakingHostKey),
+	}
+
 	if publicIP != "" {
 		// User specified a specific public IP to use.
 		ip := net.ParseIP(publicIP)
 		if ip == nil {
 			return node.IPConfig{}, fmt.Errorf("invalid IP Address %s", publicIP)
 		}
-		return node.IPConfig{
-			IPPort:           ips.NewDynamicIPPort(ip, stakingPort),
-			IPUpdater:        dynamicip.NewNoUpdater(),
-			IPResolutionFreq: ipResolutionFreq,
-			Nat:              nat.NewNoRouter(),
-		}, nil
+		ipConfig.IPPort = ips.NewDynamicIPPort(ip, stakingPort)
+		return ipConfig, nil
 	}
 	if ipResolutionService != "" {
 		// User specified to use dynamic IP resolution.
@@ -630,18 +634,9 @@ func getIPConfig(v *viper.Viper) (node.IPConfig, error) {
 		if err != nil {
 			return node.IPConfig{}, fmt.Errorf("couldn't resolve public IP: %w", err)
 		}
-		ipPort := ips.NewDynamicIPPort(ip, stakingPort)
-
-		return node.IPConfig{
-			IPPort: ipPort,
-			IPUpdater: dynamicip.NewUpdater(
-				ipPort,
-				resolver,
-				ipResolutionFreq,
-			),
-			IPResolutionFreq: ipResolutionFreq,
-			Nat:              nat.NewNoRouter(),
-		}, nil
+		ipConfig.IPPort = ips.NewDynamicIPPort(ip, stakingPort)
+		ipConfig.IPUpdater = dynamicip.NewUpdater(ipConfig.IPPort, resolver, ipResolutionFreq)
+		return ipConfig, nil
 	}
 
 	// User didn't specify a public IP to use, and they didn't specify a public IP resolution
@@ -651,13 +646,10 @@ func getIPConfig(v *viper.Viper) (node.IPConfig, error) {
 	if err != nil {
 		return node.IPConfig{}, fmt.Errorf("public IP / IP resolution service not given and failed to resolve IP with NAT: %w", err)
 	}
-	return node.IPConfig{
-		Nat:                   nat,
-		AttemptedNATTraversal: true,
-		IPPort:                ips.NewDynamicIPPort(ip, stakingPort),
-		IPUpdater:             dynamicip.NewNoUpdater(),
-		IPResolutionFreq:      ipResolutionFreq,
-	}, nil
+	ipConfig.IPPort = ips.NewDynamicIPPort(ip, stakingPort)
+	ipConfig.Nat = nat
+	ipConfig.AttemptedNATTraversal = true
+	return ipConfig, nil
 }
 
 func getProfilerConfig(v *viper.Viper) (profiler.Config, error) {

config/flags.go

@@ -258,6 +258,7 @@ func addNodeFlags(fs *pflag.FlagSet) {
 	fs.Duration(NetworkHealthMaxOutstandingDurationKey, 5*time.Minute, "Node reports unhealthy if there has been a request outstanding for this duration")
 
 	// Staking
+	fs.String(StakingHostKey, "", "Address of the consensus server") // Bind to all interfaces by default.
 	fs.Uint(StakingPortKey, DefaultStakingPort, "Port of the consensus server")
 	// TODO: Remove this flag in the future
 	fs.Bool(StakingEnabledKey, true, "Enable staking. If enabled, Network TLS is required")

config/keys.go

@@ -68,6 +68,7 @@ const (
 	StateSyncIDsKey                                    = "state-sync-ids"
 	BootstrapIPsKey                                    = "bootstrap-ips"
 	BootstrapIDsKey                                    = "bootstrap-ids"
+	StakingHostKey                                     = "staking-host"
 	StakingPortKey                                     = "staking-port"
 	StakingEnabledKey                                  = "staking-enabled" // TODO: deprecated, remove this
 	StakingEphemeralCertEnabledKey                     = "staking-ephemeral-cert-enabled"

node/config.go

@@ -81,6 +81,12 @@ type IPConfig struct {
 	AttemptedNATTraversal bool `json:"attemptedNATTraversal"`
 	// Tries to perform network address translation
 	Nat nat.Router `json:"-"`
+	// The host portion of the address to listen on. The port to
+	// listen on will be sourced from IPPort.
+	//
+	// - If empty, listen on all interfaces (both ipv4 and ipv6).
+	// - If populated, listen only on the specified address.
+	ListenHost string `json:"listenHost"`
 }
 
 type StakingConfig struct {

node/node.go

@@ -212,7 +212,27 @@ type Node struct {
 // Assumes [n.CPUTracker] and [n.CPUTargeter] have been initialized.
 func (n *Node) initNetworking(primaryNetVdrs validators.Set) error {
 	currentIPPort := n.Config.IPPort.IPPort()
-	listener, err := net.Listen(constants.NetworkType, fmt.Sprintf(":%d", currentIPPort.Port))
+
+	// Providing either loopback address - `::1` for ipv6 and `127.0.0.1` for ipv4 - as the listen
+	// host will avoid the need for a firewall exception on recent MacOS:
+	//
+	//   - MacOS requires a manually-approved firewall exception [1] for each version of a given
+	//   binary that wants to bind to all interfaces (i.e. with an address of `:[port]`). Each
+	//   compiled version of avalanchego requires a separate exception to be allowed to bind to all
+	//   interfaces.
+	//
+	//   - A firewall exception is not required to bind to a loopback interface, but the only way for
+	//   Listen() to bind to loopback for both ipv4 and ipv6 is to bind to all interfaces [2] which
+	//   requires an exception.
+	//
+	//   - Thus, the only way to start a node on MacOS without approving a firewall exception for the
+	//   avalanchego binary is to bind to loopback by specifying the host to be `::1` or `127.0.0.1`.
+	//
+	// 1: https://apple.stackexchange.com/questions/393715/do-you-want-the-application-main-to-accept-incoming-network-connections-pop
+	// 2: https://github.com/golang/go/issues/56998
+	listenAddress := net.JoinHostPort(n.Config.ListenHost, fmt.Sprintf("%d", currentIPPort.Port))
+
+	listener, err := net.Listen(constants.NetworkType, listenAddress)
 	if err != nil {
 		return err
 	}