Refactoring: move tuntap and icmpv6 into separate package

src/tuntap/tun_linux.go

@@ -0,0 +1,86 @@
+// +build !mobile
+
+package tuntap
+
+// The linux platform specific tun parts
+
+import (
+	"errors"
+	"fmt"
+	"net"
+
+	"github.com/docker/libcontainer/netlink"
+
+	water "github.com/yggdrasil-network/water"
+)
+
+// Configures the TAP adapter with the correct IPv6 address and MTU.
+func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
+	var config water.Config
+	if iftapmode {
+		config = water.Config{DeviceType: water.TAP}
+	} else {
+		config = water.Config{DeviceType: water.TUN}
+	}
+	if ifname != "" && ifname != "auto" {
+		config.Name = ifname
+	}
+	iface, err := water.New(config)
+	if err != nil {
+		panic(err)
+	}
+	tun.iface = iface
+	tun.mtu = getSupportedMTU(mtu)
+	// The following check is specific to Linux, as the TAP driver only supports
+	// an MTU of 65535-14 to make room for the ethernet headers. This makes sure
+	// that the MTU gets rounded down to 65521 instead of causing a panic.
+	if iftapmode {
+		if tun.mtu > 65535-tun_ETHER_HEADER_LENGTH {
+			tun.mtu = 65535 - tun_ETHER_HEADER_LENGTH
+		}
+	}
+	// Friendly output
+	tun.core.log.Infof("Interface name: %s", tun.iface.Name())
+	tun.core.log.Infof("Interface IPv6: %s", addr)
+	tun.core.log.Infof("Interface MTU: %d", tun.mtu)
+	return tun.setupAddress(addr)
+}
+
+// Configures the TAP adapter with the correct IPv6 address and MTU. Netlink
+// is used to do this, so there is not a hard requirement on "ip" or "ifconfig"
+// to exist on the system, but this will fail if Netlink is not present in the
+// kernel (it nearly always is).
+func (tun *TunAdapter) setupAddress(addr string) error {
+	// Set address
+	var netIF *net.Interface
+	ifces, err := net.Interfaces()
+	if err != nil {
+		return err
+	}
+	for _, ifce := range ifces {
+		if ifce.Name == tun.iface.Name() {
+			var newIF = ifce
+			netIF = &newIF // Don't point inside ifces, it's apparently unsafe?...
+		}
+	}
+	if netIF == nil {
+		return errors.New(fmt.Sprintf("Failed to find interface: %s", tun.iface.Name()))
+	}
+	ip, ipNet, err := net.ParseCIDR(addr)
+	if err != nil {
+		return err
+	}
+	err = netlink.NetworkLinkAddIp(netIF, ip, ipNet)
+	if err != nil {
+		return err
+	}
+	err = netlink.NetworkSetMTU(netIF, tun.mtu)
+	if err != nil {
+		return err
+	}
+	netlink.NetworkLinkUp(netIF)
+	if err != nil {
+		return err
+	}
+	return nil
+}