net: replace dst_cache ip6_tunnel implementation with the generic one
This also fix a potential race into the existing tunnel code, which
could lead to the wrong dst to be permanenty cached:
CPU1: CPU2:
<xmit on ip6_tunnel>
<cache lookup fails>
dst = ip6_route_output(...)
<tunnel params are changed via nl>
dst_cache_reset() // no effect,
// the cache is empty
dst_cache_set() // the wrong dst
// is permanenty stored
// into the cache
With the new dst implementation the above race is not possible
since the first cache lookup after dst_cache_reset will fail due
to the timestamp check
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
5 files changed