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| author | David S. Miller <davem@davemloft.net> | 2010-12-13 23:52:14 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-12-13 23:52:14 +0300 |
| commit | 0dbaee3b37e118a96bb7b8eb0d9bbaeeb46264be (patch) | |
| tree | 37000c5d7e663e4ae9800a7bcde9934984b8bae9 /net/decnet/dn_route.c | |
| parent | cc6f02dd490dac4ad821d5077b934c9b37037cd0 (diff) | |
| download | linux-0dbaee3b37e118a96bb7b8eb0d9bbaeeb46264be.tar.xz | |
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/decnet/dn_route.c')
| -rw-r--r-- | net/decnet/dn_route.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c index e2e926841fe6..b8a5c0515be8 100644 --- a/net/decnet/dn_route.c +++ b/net/decnet/dn_route.c @@ -110,6 +110,7 @@ static unsigned long dn_rt_deadline; static int dn_dst_gc(struct dst_ops *ops); static struct dst_entry *dn_dst_check(struct dst_entry *, __u32); +static unsigned int dn_dst_default_advmss(const struct dst_entry *dst); static struct dst_entry *dn_dst_negative_advice(struct dst_entry *); static void dn_dst_link_failure(struct sk_buff *); static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu); @@ -129,6 +130,7 @@ static struct dst_ops dn_dst_ops = { .gc_thresh = 128, .gc = dn_dst_gc, .check = dn_dst_check, + .default_advmss = dn_dst_default_advmss, .negative_advice = dn_dst_negative_advice, .link_failure = dn_dst_link_failure, .update_pmtu = dn_dst_update_pmtu, @@ -245,7 +247,8 @@ static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu) } if (!(dst_metric_locked(dst, RTAX_ADVMSS))) { u32 mss = mtu - DN_MAX_NSP_DATA_HEADER; - if (dst_metric(dst, RTAX_ADVMSS) > mss) + u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS); + if (!existing_mss || existing_mss > mss) dst_metric_set(dst, RTAX_ADVMSS, mss); } } @@ -795,12 +798,17 @@ static int dn_rt_bug(struct sk_buff *skb) return NET_RX_DROP; } +static unsigned int dn_dst_default_advmss(const struct dst_entry *dst) +{ + return dn_mss_from_pmtu(dst->dev, dst_mtu(dst)); +} + static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res) { struct dn_fib_info *fi = res->fi; struct net_device *dev = rt->dst.dev; struct neighbour *n; - unsigned mss; + unsigned int metric; if (fi) { if (DN_FIB_RES_GW(*res) && @@ -820,10 +828,12 @@ static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res) if (dst_metric(&rt->dst, RTAX_MTU) == 0 || dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu) dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu); - mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst)); - if (dst_metric(&rt->dst, RTAX_ADVMSS) == 0 || - dst_metric(&rt->dst, RTAX_ADVMSS) > mss) - dst_metric_set(&rt->dst, RTAX_ADVMSS, mss); + metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS); + if (metric) { + unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst)); + if (metric > mss) + dst_metric_set(&rt->dst, RTAX_ADVMSS, mss); + } return 0; } |