tree 37000c5d7e663e4ae9800a7bcde9934984b8bae9
parent cc6f02dd490dac4ad821d5077b934c9b37037cd0
author David S. Miller <davem@davemloft.net> 1292273534 -0800
committer David S. Miller <davem@davemloft.net> 1292273534 -0800

net: Abstract default ADVMSS behind an accessor.

Make all RTAX_ADVMSS metric accesses go through a new helper function,
dst_metric_advmss().

Leave the actual default metric as "zero" in the real metric slot,
and compute the actual default value dynamically via a new dst_ops
AF specific callback.

For stacked IPSEC routes, we use the advmss of the path which
preserves existing behavior.

Unlike ipv4/ipv6, DecNET ties the advmss to the mtu and thus updates
advmss on pmtu updates.  This inconsistency in advmss handling
results in more raw metric accesses than I wish we ended up with.

Signed-off-by: David S. Miller <davem@davemloft.net>