tun/netstack: enable TCP Selective Acknowledgements

Enable TCP SACK for the gVisor Stack used in tun/netstack. This can
improve throughput by an order of magnitude in the presence of packet
loss.

Reviewed-by: James Tucker <james@tailscale.com>
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jordan Whited 2023-03-09 11:06:01 -08:00 committed by Jason A. Donenfeld
parent 6901984f6a
commit 5819c6af28

View File

@ -65,8 +65,13 @@ func CreateNetTUN(localAddresses, dnsServers []netip.Addr, mtu int) (tun.Device,
dnsServers: dnsServers,
mtu: mtu,
}
sackEnabledOpt := tcpip.TCPSACKEnabled(true) // TCP SACK is disabled by default
tcpipErr := dev.stack.SetTransportProtocolOption(tcp.ProtocolNumber, &sackEnabledOpt)
if tcpipErr != nil {
return nil, nil, fmt.Errorf("could not enable TCP SACK: %v", tcpipErr)
}
dev.ep.AddNotify(dev)
tcpipErr := dev.stack.CreateNIC(1, dev.ep)
tcpipErr = dev.stack.CreateNIC(1, dev.ep)
if tcpipErr != nil {
return nil, nil, fmt.Errorf("CreateNIC: %v", tcpipErr)
}