feat(linux): add IPv6 support for VPN gateway

Author: NNdroid

application.go

@@ -108,7 +108,7 @@ type NetManager interface {
 	EnableClientRoutes(tunIfName string) error
 	DisableClientRoutes() error
 	ClientRoutesActive() bool
-	EnableServerNAT(awlSubnet, tunIfName string) error
+	EnableServerNAT(awlSubnet, awlSubnet6, tunIfName string) error
 	DisableServerNAT() error
 	ServerNATActive() bool
 }
@@ -145,12 +145,16 @@ func (a *Application) Init(ctx context.Context, tunDevice tun.Device) error {
 		a.logger.Info("VPN interface is disabled from config")
 	} else {
 		localIP, netMask := a.Conf.VPNLocalIPMask()
+		localIPv6, netMaskv6 := a.Conf.VPNLocalIPMaskV6()
 		interfaceName := a.Conf.VPNConfig.InterfaceName
-		a.vpnDevice, err = vpn.NewDevice(tunDevice, interfaceName, localIP, netMask)
+		a.vpnDevice, err = vpn.NewDevice(tunDevice, interfaceName, localIP, netMask, localIPv6, netMaskv6)
 		if err != nil {
 			return fmt.Errorf("failed to init vpn: %v", err)
 		}
 		a.logger.Infof("VPN interface created. Name: %s CIDR: %s", interfaceName, &net.IPNet{IP: localIP, Mask: netMask})
+		if localIPv6 != nil {
+			a.logger.Infof("VPN interface IPv6: %s", &net.IPNet{IP: localIPv6, Mask: netMaskv6})
+		}
 
 		a.Tunnel = service.NewTunnel(a.P2p, a.vpnDevice, a.Conf, a.Eventbus)
 		go a.vpnDevice.ReadTUNPackets(a.Tunnel.HandleReadPackets)

config/config.go

@@ -78,6 +78,7 @@ type (
 		DisableVPNInterface bool   `json:"disableVPNInterface"`
 		InterfaceName       string `json:"interfaceName"`
 		IPNet               string `json:"ipNet"`
+		IPNetV6             string `json:"ipNetV6"`
 	}
 	// VPNGatewayConfig configures full-tunnel VPN gateway mode.
 	//

config/network_addr.go

@@ -10,7 +10,8 @@ import (
 const (
 	DefaultVPNInterfaceName = "awl0"
 	// TODO: generate subnets if this has already taken
-	DefaultVPNNetworkSubnet = "10.66.0.1/16"
+	DefaultVPNNetworkSubnet  = "10.66.0.1/16"
+	DefaultVPNNetworkSubnet6 = "fd00:66:0::1/48"
 )
 
 func (c *Config) VPNLocalIPMask() (net.IP, net.IPMask) {
@@ -29,6 +30,25 @@ func (c *Config) VPNLocalIPMaskUnlocked() (net.IP, net.IPMask) {
 	return localIP.To4(), ipNet.Mask
 }
 
+func (c *Config) VPNLocalIPMaskV6() (net.IP, net.IPMask) {
+	c.RLock()
+	defer c.RUnlock()
+
+	return c.VPNLocalIPMaskV6Unlocked()
+}
+
+func (c *Config) VPNLocalIPMaskV6Unlocked() (net.IP, net.IPMask) {
+	if c.VPNConfig.IPNetV6 == "" {
+		return nil, nil
+	}
+	localIP, ipNet, err := net.ParseCIDR(c.VPNConfig.IPNetV6)
+	if err != nil {
+		logger.Errorf("parse CIDR %s: %v", c.VPNConfig.IPNetV6, err)
+		return nil, nil
+	}
+	return localIP.To16(), ipNet.Mask
+}
+
 // GenerateNextIpAddr is not thread safe.
 func (c *Config) GenerateNextIpAddr() string {
 	return c.GenerateNextIpAddrExcept(nil)

config/other.go

@@ -174,9 +174,15 @@ func setDefaults(conf *Config, bus awlevent.Bus) {
 	if conf.VPNConfig.IPNet == "" {
 		conf.VPNConfig.IPNet = DefaultVPNNetworkSubnet
 	}
+	if conf.VPNConfig.IPNetV6 == "" {
+		conf.VPNConfig.IPNetV6 = DefaultVPNNetworkSubnet6
+	}
 	if ip, _ := conf.VPNLocalIPMask(); ip == nil {
 		conf.VPNConfig.IPNet = DefaultVPNNetworkSubnet
 	}
+	if ip, _ := conf.VPNLocalIPMaskV6(); ip == nil {
+		conf.VPNConfig.IPNetV6 = DefaultVPNNetworkSubnet6
+	}
 	if conf.VPNConfig.InterfaceName == "" {
 		if runtime.GOOS == "darwin" {
 			conf.VPNConfig.InterfaceName = "utun"