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>
diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 0065e7e..2af15b1 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -829,7 +829,7 @@
return -EINVAL;
scp->state = DN_CC;
- scp->segsize_loc = dst_metric(__sk_dst_get(sk), RTAX_ADVMSS);
+ scp->segsize_loc = dst_metric_advmss(__sk_dst_get(sk));
dn_send_conn_conf(sk, allocation);
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
@@ -958,7 +958,7 @@
sk->sk_route_caps = sk->sk_dst_cache->dev->features;
sock->state = SS_CONNECTING;
scp->state = DN_CI;
- scp->segsize_loc = dst_metric(sk->sk_dst_cache, RTAX_ADVMSS);
+ scp->segsize_loc = dst_metric_advmss(sk->sk_dst_cache);
dn_nsp_send_conninit(sk, NSP_CI);
err = -EINPROGRESS;