From 69b535c01feb1066a92670d400afe870aca02b20 Mon Sep 17 00:00:00 2001 From: Brad Fitzpatrick Date: Thu, 2 Jun 2022 08:17:12 -0700 Subject: [PATCH] wgengine/netstack: replace a 1500 with a const + doc Per post-submit code review feedback of 1336fb740b7f from @maisem. Change-Id: Ic5c16306cbdee1029518448642304981f77ea1fd Signed-off-by: Brad Fitzpatrick --- wgengine/netstack/netstack.go | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/wgengine/netstack/netstack.go b/wgengine/netstack/netstack.go index 34c8656fc..f9a8311d8 100644 --- a/wgengine/netstack/netstack.go +++ b/wgengine/netstack/netstack.go @@ -133,6 +133,11 @@ var handleSSH func(logger.Logf, *ipnlocal.LocalBackend, net.Conn) error const nicID = 1 const mtu = tstun.DefaultMTU +// maxUDPPacketSize is the maximum size of a UDP packet we copy in startPacketCopy +// when relaying UDP packets. We don't use the 'mtu' const in anticipation of +// one day making the MTU more dynamic. +const maxUDPPacketSize = 1500 + // Create creates and populates a new Impl. func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn, dialer *tsdial.Dialer, dns *dns.Manager) (*Impl, error) { if mc == nil { @@ -1018,7 +1023,7 @@ func startPacketCopy(ctx context.Context, cancel context.CancelFunc, dst net.Pac } go func() { defer cancel() // tear down the other direction's copy - pkt := make([]byte, 1500) + pkt := make([]byte, maxUDPPacketSize) for { select { case <-ctx.Done():