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>
This commit is contained in:
David S. Miller
2010-12-13 12:52:14 -08:00
parent cc6f02dd49
commit 0dbaee3b37
11 changed files with 75 additions and 33 deletions

View File

@@ -829,7 +829,7 @@ static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
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 @@ static int __dn_connect(struct sock *sk, struct sockaddr_dn *addr, int addrlen,
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;