Fix couple of issues with MTU calculations

This commit is contained in:
Neil Alexander 2019-11-20 22:11:52 +00:00
parent ec46b217da
commit 9fca3640f9
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
2 changed files with 7 additions and 20 deletions

View File

@ -170,22 +170,17 @@ func (tun *TunAdapter) _start() error {
nodeID := crypto.GetNodeID(&boxPub)
tun.addr = *address.AddrForNodeID(nodeID)
tun.subnet = *address.SubnetForNodeID(nodeID)
tun.mtu = current.IfMTU
ifname := current.IfName
iftapmode := current.IfTAPMode
addr := fmt.Sprintf("%s/%d", net.IP(tun.addr[:]).String(), 8*len(address.GetPrefix())-1)
if ifname != "none" {
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" {
if current.IfName == "none" || current.IfName == "dummy" {
tun.log.Debugln("Not starting TUN/TAP as ifname is none or dummy")
return nil
}
if err := tun.setup(current.IfName, current.IfTAPMode, addr, current.IfMTU); 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()))
}
tun.isOpen = true
go tun.handler()
tun.reader.Act(nil, tun.reader._read) // Start the reader

View File

@ -27,14 +27,6 @@ func (tun *TunAdapter) setup(ifname string, iftapmode bool, addr string, mtu int
}
tun.iface = iface
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.
if iftapmode {
if tun.mtu > 65535-tun_ETHER_HEADER_LENGTH {
tun.mtu = 65535 - tun_ETHER_HEADER_LENGTH
}
}
// Friendly output
tun.log.Infof("Interface name: %s", tun.iface.Name())
tun.log.Infof("Interface IPv6: %s", addr)