diff options
| -rw-r--r-- | tun/tun_linux.go | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/tun/tun_linux.go b/tun/tun_linux.go index 2f97ebb..1e44b59 100644 --- a/tun/tun_linux.go +++ b/tun/tun_linux.go @@ -66,14 +66,19 @@ func (tun *NativeTun) routineHackListener() { } switch err { case unix.EINVAL: + // If the tunnel is up, it reports that write() is + // allowed but we provided invalid data. tun.events <- EventUp case unix.EIO: + // If the tunnel is down, it reports that no I/O + // is possible, without checking our provided data. tun.events <- EventDown default: return } select { case <-time.After(time.Second): + // nothing case <-tun.statusListenersShutdown: return } @@ -128,6 +133,7 @@ func (tun *NativeTun) routineNetlinkListener() { default: } + wasEverUp := false for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; { hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0])) @@ -151,10 +157,16 @@ func (tun *NativeTun) routineNetlinkListener() { if info.Flags&unix.IFF_RUNNING != 0 { tun.events <- EventUp + wasEverUp = true } if info.Flags&unix.IFF_RUNNING == 0 { - tun.events <- EventDown + // Don't emit EventDown before we've ever emitted EventUp. + // This avoids a startup race with HackListener, which + // might detect Up before we have finished reporting Down. + if wasEverUp { + tun.events <- EventDown + } } tun.events <- EventMTUUpdate |