tcp: Enable SO_KEEPALIVE if we see keep-alive segments from container / guest

This is an approximation, as enabling SO_KEEPALIVE doesn't mean that
a keep-alive segment will be sent right away, rather that keep-alive
segments will start being sent if the connection is idle.

On the other hand, we don't have direct control over the host-side
TCP, so this is probably the best approximation we can get.

By default, namespaces inherit keep-alive parameters from their parent
namespace, so we can assume that, in case of a container, we'll wait
for the same interval it took for the container to start sending us
keep-alives, effectively doubling that interval.

To keep this simple, set SO_KEEPALIVE whenever we see a keep-alive
segment, instead of tracking its state. Keep-alive segments are
relatively infrequent, so we don't expect any substantial cost from
doing that.

Reported-by: Dominic Kohls <Dominic.Wenzler@rewe-group.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions