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| author | David S. Miller <davem@davemloft.net> | 2010-12-13 12:52:14 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-12-13 12:52:14 -0800 |
| commit | 0dbaee3b37e118a96bb7b8eb0d9bbaeeb46264be (patch) | |
| tree | 37000c5d7e663e4ae9800a7bcde9934984b8bae9 /net/ipv4/tcp_output.c | |
| parent | cc6f02dd490dac4ad821d5077b934c9b37037cd0 (diff) | |
| download | linux-0dbaee3b37e118a96bb7b8eb0d9bbaeeb46264be.tar.bz2 | |
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>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 97041f24cd27..2d390669d406 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -119,9 +119,13 @@ static __u16 tcp_advertise_mss(struct sock *sk) struct dst_entry *dst = __sk_dst_get(sk); int mss = tp->advmss; - if (dst && dst_metric(dst, RTAX_ADVMSS) < mss) { - mss = dst_metric(dst, RTAX_ADVMSS); - tp->advmss = mss; + if (dst) { + unsigned int metric = dst_metric_advmss(dst); + + if (metric < mss) { + mss = metric; + tp->advmss = mss; + } } return (__u16)mss; @@ -2422,7 +2426,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, skb_dst_set(skb, dst_clone(dst)); - mss = dst_metric(dst, RTAX_ADVMSS); + mss = dst_metric_advmss(dst); if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss) mss = tp->rx_opt.user_mss; @@ -2556,7 +2560,7 @@ static void tcp_connect_init(struct sock *sk) if (!tp->window_clamp) tp->window_clamp = dst_metric(dst, RTAX_WINDOW); - tp->advmss = dst_metric(dst, RTAX_ADVMSS); + tp->advmss = dst_metric_advmss(dst); if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < tp->advmss) tp->advmss = tp->rx_opt.user_mss; |