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| author | Brad Fitzpatrick <bradfitz@tailscale.com> | 2020-08-07 12:06:32 -0700 |
|---|---|---|
| committer | Brad Fitzpatrick <brad@danga.com> | 2020-08-07 12:16:12 -0700 |
| commit | c64a43a734f52a6dd4eb01e9bc72d4b49ae3c776 (patch) | |
| tree | e8018490517fe298c8f3a1d089139a4ae2e8d2d1 | |
| parent | 9318b4758cb9ed7357c42045ea03d4a8f268db59 (diff) | |
| download | tailscale-c64a43a734f52a6dd4eb01e9bc72d4b49ae3c776.tar.xz tailscale-c64a43a734f52a6dd4eb01e9bc72d4b49ae3c776.zip | |
wgengine/router: set MTU on Windows to min(configured,possible)
Fixes tailscale/corp#542
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
| -rw-r--r-- | wgengine/router/ifconfig_windows.go | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/wgengine/router/ifconfig_windows.go b/wgengine/router/ifconfig_windows.go index a9b99b89b..78388ccc0 100644 --- a/wgengine/router/ifconfig_windows.go +++ b/wgengine/router/ifconfig_windows.go @@ -121,6 +121,13 @@ func monitorDefaultRoutes(device *device.Device, autoMTU bool, tun *tun.NativeTu return err } iface.NlMtu = mtu - 80 + // If the TUN device was created with a smaller MTU, + // though, such as 1280, we don't want to go bigger than + // configured. (See the comment on minimalMTU in the + // wgengine package.) + if min, err := tun.MTU(); err == nil && min < int(iface.NlMtu) { + iface.NlMtu = uint32(min) + } if iface.NlMtu < 576 { iface.NlMtu = 576 } |