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mirror of https://github.com/cwinfo/yggdrasil-go.git synced 2024-11-10 04:00:37 +00:00

Fix setting up of MTU when value is outside of acceptable bounds, also account for ethernet headers in calculations, notify about clipping to stdout

This commit is contained in:
Neil Alexander 2019-11-19 14:20:11 +00:00
parent 17a711ab8a
commit f49d9de421
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
6 changed files with 32 additions and 16 deletions

View File

@ -63,9 +63,12 @@ type TunOptions struct {
// Gets the maximum supported MTU for the platform based on the defaults in
// defaults.GetDefaults().
func getSupportedMTU(mtu int) int {
if mtu > defaults.GetDefaults().MaximumIfMTU {
return defaults.GetDefaults().MaximumIfMTU
func getSupportedMTU(mtu int, istapmode bool) int {
if mtu < 1280 {
return 1280
}
if mtu > MaximumMTU(istapmode) {
return MaximumMTU(istapmode)
}
return mtu
}
@ -80,7 +83,7 @@ func (tun *TunAdapter) Name() string {
// the maximum value is determined by your platform. The returned value will
// never exceed that of MaximumMTU().
func (tun *TunAdapter) MTU() int {
return getSupportedMTU(tun.mtu)
return getSupportedMTU(tun.mtu, tun.IsTAP())
}
// IsTAP returns true if the adapter is a TAP adapter (Layer 2) or false if it
@ -97,7 +100,11 @@ func DefaultName() string {
// DefaultMTU gets the default TUN/TAP interface MTU for your platform. This can
// be as high as MaximumMTU(), depending on platform, but is never lower than 1280.
func DefaultMTU() int {
return defaults.GetDefaults().DefaultIfMTU
ehbytes := 0
if DefaultIsTAP() {
ehbytes = 14
}
return defaults.GetDefaults().DefaultIfMTU - ehbytes
}
// DefaultIsTAP returns true if the default adapter mode for the current
@ -109,8 +116,12 @@ func DefaultIsTAP() bool {
// MaximumMTU returns the maximum supported TUN/TAP interface MTU for your
// platform. This can be as high as 65535, depending on platform, but is never
// lower than 1280.
func MaximumMTU() int {
return defaults.GetDefaults().MaximumIfMTU
func MaximumMTU(iftapmode bool) int {
ehbytes := 0
if iftapmode {
ehbytes = 14
}
return defaults.GetDefaults().MaximumIfMTU - ehbytes
}
// Init initialises the TUN/TAP module. You must have acquired a Listener from
@ -167,6 +178,9 @@ func (tun *TunAdapter) _start() error {
if err := tun.setup(ifname, iftapmode, addr, tun.mtu); err != nil {
return err
}
if tun.MTU() != current.IfMTU {
tun.log.Warnf("Warning: Interface MTU %d automatically adjusted to %d (supported range is 1280-%d)", current.IfMTU, tun.MTU(), MaximumMTU(tun.IsTAP()))
}
}
if ifname == "none" || ifname == "dummy" {
tun.log.Debugln("Not starting TUN/TAP as ifname is none or dummy")
@ -176,7 +190,7 @@ func (tun *TunAdapter) _start() error {
go tun.handler()
tun.reader.Act(nil, tun.reader._read) // Start the reader
tun.icmpv6.Init(tun)
if iftapmode {
if tun.IsTAP() {
go tun.icmpv6.Solicit(tun.addr)
}
tun.ckr.init(tun)

View File

@ -99,7 +99,7 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
panic(err)
}
tun.iface = iface
tun.mtu = getSupportedMTU(mtu)
tun.mtu = getSupportedMTU(mtu, iftapmode)
return tun.setupAddress(addr)
}

View File

@ -18,7 +18,8 @@ import (
// Configures the "utun" adapter with the correct IPv6 address and MTU.
func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
if iftapmode {
tun.log.Warnln("TAP mode is not supported on this platform, defaulting to TUN")
tun.log.Warnln("Warning: TAP mode is not supported on this platform, defaulting to TUN")
iftapmode = false
}
config := water.Config{DeviceType: water.TUN}
iface, err := water.New(config)
@ -26,7 +27,7 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
panic(err)
}
tun.iface = iface
tun.mtu = getSupportedMTU(mtu)
tun.mtu = getSupportedMTU(mtu, iftapmode)
return tun.setupAddress(addr)
}

View File

@ -26,7 +26,7 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
panic(err)
}
tun.iface = iface
tun.mtu = getSupportedMTU(mtu)
tun.mtu = getSupportedMTU(mtu, iftapmode)
// 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.

View File

@ -21,13 +21,13 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
panic(err)
}
tun.iface = iface
tun.mtu = getSupportedMTU(mtu)
tun.mtu = getSupportedMTU(mtu, iftapmode)
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("Platform not supported, you must set the address of", tun.iface.Name(), "to", addr)
tun.log.Warnln("Warning: Platform not supported, you must set the address of", tun.iface.Name(), "to", addr)
return nil
}

View File

@ -17,7 +17,8 @@ import (
// delegate the hard work to "netsh".
func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int) error {
if !iftapmode {
tun.log.Warnln("TUN mode is not supported on this platform, defaulting to TAP")
tun.log.Warnln("Warning: TUN mode is not supported on this platform, defaulting to TAP")
iftapmode = true
}
config := water.Config{DeviceType: water.TAP}
config.PlatformSpecificParams.ComponentID = "tap0901"
@ -60,7 +61,7 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
panic(err)
}
tun.iface = iface
tun.mtu = getSupportedMTU(mtu)
tun.mtu = getSupportedMTU(mtu, iftapmode)
err = tun.setupMTU(tun.mtu)
if err != nil {
panic(err)