diff options
| author | David S. Miller <davem@davemloft.net> | 2010-12-14 13:01:14 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-12-14 13:01:14 -0800 |
| commit | d33e455337ea2c71d09d7f4367d6ad6dd32b6965 (patch) | |
| tree | d1b35b1be5ab73df6f7e57b86a2e68fad2990adf /net/ipv4 | |
| parent | 9fe146aef44afe5ec677d8150b6ae94e09b773f7 (diff) | |
| download | linux-d33e455337ea2c71d09d7f4367d6ad6dd32b6965.tar.bz2 | |
net: Abstract default MTU metric calculation behind an accessor.
Like RTAX_ADVMSS, make the default calculation go through a dst_ops
method rather than caching the computation in the routing cache
entries.
Now dst metrics are pretty much left as-is when new entries are
created, thus optimizing metric sharing becomes a real possibility.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/route.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 80997333db0c..ae520963540f 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -140,6 +140,7 @@ static unsigned long expires_ljiffies; static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); static unsigned int ipv4_default_advmss(const struct dst_entry *dst); +static unsigned int ipv4_default_mtu(const struct dst_entry *dst); static void ipv4_dst_destroy(struct dst_entry *dst); static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); static void ipv4_link_failure(struct sk_buff *skb); @@ -157,6 +158,7 @@ static struct dst_ops ipv4_dst_ops = { .gc = rt_garbage_collect, .check = ipv4_dst_check, .default_advmss = ipv4_default_advmss, + .default_mtu = ipv4_default_mtu, .destroy = ipv4_dst_destroy, .ifdown = ipv4_dst_ifdown, .negative_advice = ipv4_negative_advice, @@ -1812,6 +1814,23 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst) return advmss; } +static unsigned int ipv4_default_mtu(const struct dst_entry *dst) +{ + unsigned int mtu = dst->dev->mtu; + + if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { + const struct rtable *rt = (const struct rtable *) dst; + + if (rt->rt_gateway != rt->rt_dst && mtu > 576) + mtu = 576; + } + + if (mtu > IP_MAX_MTU) + mtu = IP_MAX_MTU; + + return mtu; +} + static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag) { struct dst_entry *dst = &rt->dst; @@ -1822,18 +1841,10 @@ static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag) FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) rt->rt_gateway = FIB_RES_GW(*res); dst_import_metrics(dst, fi->fib_metrics); - if (fi->fib_mtu == 0) { - dst_metric_set(dst, RTAX_MTU, dst->dev->mtu); - if (dst_metric_locked(dst, RTAX_MTU) && - rt->rt_gateway != rt->rt_dst && - dst->dev->mtu > 576) - dst_metric_set(dst, RTAX_MTU, 576); - } #ifdef CONFIG_NET_CLS_ROUTE dst->tclassid = FIB_RES_NH(*res).nh_tclassid; #endif - } else - dst_metric_set(dst, RTAX_MTU, dst->dev->mtu); + } if (dst_mtu(dst) > IP_MAX_MTU) dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU); |