Rename tuntap package to tun

We haven't had TAP support in ages.

src/tun/tun_other.go

@@ -0,0 +1,33 @@
+//go:build !linux && !darwin && !windows && !openbsd && !freebsd && !mobile
+// +build !linux,!darwin,!windows,!openbsd,!freebsd,!mobile
+
+package tun
+
+// This is to catch unsupported platforms
+// If your platform supports tun devices, you could try configuring it manually
+
+import (
+	wgtun "golang.zx2c4.com/wireguard/tun"
+)
+
+// Configures the TUN adapter with the correct IPv6 address and MTU.
+func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
+	iface, err := wgtun.CreateTUN(ifname, mtu)
+	if err != nil {
+		panic(err)
+	}
+	tun.iface = iface
+	if mtu, err := iface.MTU(); err == nil {
+		tun.mtu = getSupportedMTU(uint64(mtu))
+	} else {
+		tun.mtu = 0
+	}
+	return tun.setupAddress(addr)
+}
+
+// We don't know how to set the IPv6 address on an unknown platform, therefore
+// write about it to stdout and don't try to do anything further.
+func (tun *TunAdapter) setupAddress(addr string) error {
+	tun.log.Warnln("Warning: Platform not supported, you must set the address of", tun.Name(), "to", addr)
+	return nil
+}