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| author | Gao Feng <fgao@ikuai8.com> | 2017-04-12 12:34:03 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-13 13:19:48 -0400 |
| commit | 7ed14d973f7c6742f4827fbbf6730cbe20888b8b (patch) | |
| tree | 64d4241faceea5a52dc9d571753373908130e2cc /net/ipv4/route.c | |
| parent | 29b904a0dd925bf2e3bcb45e478f21138b5efe3f (diff) | |
| download | talos-obmc-linux-7ed14d973f7c6742f4827fbbf6730cbe20888b8b.tar.gz talos-obmc-linux-7ed14d973f7c6742f4827fbbf6730cbe20888b8b.zip | |
net: ipv4: Refine the ipv4_default_advmss
1. Don't get the metric RTAX_ADVMSS of dst.
There are two reasons.
1) Its caller dst_metric_advmss has already invoke dst_metric_advmss
before invoke default_advmss.
2) The ipv4_default_advmss is used to get the default mss, it should
not try to get the metric like ip6_default_advmss.
2. Use sizeof(tcphdr)+sizeof(iphdr) instead of literal 40.
3. Define one new macro IPV4_MAX_PMTU instead of 65535 according to
RFC 2675, section 5.1.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/route.c')
| -rw-r--r-- | net/ipv4/route.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 5e1e60546fce..0fcc2d5192bd 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1250,15 +1250,11 @@ static void set_class_tag(struct rtable *rt, u32 tag) static unsigned int ipv4_default_advmss(const struct dst_entry *dst) { - unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); + unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); + unsigned int advmss = max_t(unsigned int, dst->dev->mtu - header_size, + ip_rt_min_advmss); - if (advmss == 0) { - advmss = max_t(unsigned int, dst->dev->mtu - 40, - ip_rt_min_advmss); - if (advmss > 65535 - 40) - advmss = 65535 - 40; - } - return advmss; + return min(advmss, IPV4_MAX_PMTU - header_size); } static unsigned int ipv4_mtu(const struct dst_entry *dst) |
