net/tstun: block looped disco traffic, take 17

It was in the wrong filter direction before, per CPU profiles
we now have.

Updates #1526 (maybe fixes? time will tell)

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2021-09-29 13:58:14 -07:00
committed by Brad Fitzpatrick
parent 3618e8d8ac
commit 080381c79f
2 changed files with 23 additions and 2 deletions

View File

@@ -413,6 +413,16 @@ func (t *Wrapper) filterOut(p *packet.Parsed) filter.Response {
return filter.DropSilently // don't pass on to OS; already handled
}
// Issue 1526 workaround: if we sent disco packets over
// Tailscale from ourselves, then drop them, as that shouldn't
// happen unless a networking stack is confused, as it seems
// macOS in Network Extension mode might be.
if p.IPProto == ipproto.UDP && // disco is over UDP; avoid isSelfDisco call for TCP/etc
t.isSelfDisco(p) {
t.logf("[unexpected] received self disco out packet over tstun; dropping")
return filter.DropSilently
}
if t.PreFilterOut != nil {
if res := t.PreFilterOut(p, t); res.IsDrop() {
return res
@@ -517,7 +527,7 @@ func (t *Wrapper) filterIn(buf []byte) filter.Response {
// macOS in Network Extension mode might be.
if p.IPProto == ipproto.UDP && // disco is over UDP; avoid isSelfDisco call for TCP/etc
t.isSelfDisco(p) {
t.logf("[unexpected] received self disco package over tstun; dropping")
t.logf("[unexpected] received self disco in packet over tstun; dropping")
return filter.DropSilently
}