tap: With pasta, don't reset on tap errors, handle write failures

Since commit 0515adceaa8f ("passt, pasta: Namespace-based sandboxing,
defer seccomp policy application"), it makes no sense to close and
reopen the tap device on error: we don't have access to /dev/net/tun
after the initial setup phase.

If we hit ENOBUFS while writing (as reported: in one case because
the kernel actually ran out of memory, with another case under
investigation), or ENOSPC, we're supposed to drop whatever data we
were trying to send: there's no room for it.

Handle EINTR just like we handled EAGAIN/EWOULDBLOCK: there's no
particular reason why sending the same data should fail again.

Anything else I can think of would be an unrecoverable error: exit
with failure then.

While at it, drop a useless cast on the write() call: it takes a
const void * anyway.

Reported-by: Gianluca Stivan <me@yawnt.com>
Reported-by: Chris Kuhn <kuhnchris@kuhnchris.eu>
Fixes: 0515adceaa8f ("passt, pasta: Namespace-based sandboxing, defer seccomp policy application")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions