diff options
| -rw-r--r-- | include/net/ip.h | 2 | ||||
| -rw-r--r-- | net/ipv4/route.c | 12 |
2 files changed, 6 insertions, 8 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index bf264a8db1ce..821cedcc8e73 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -33,6 +33,8 @@ #include <net/flow.h> #include <net/flow_dissector.h> +#define IPV4_MAX_PMTU 65535U /* RFC 2675, Section 5.1 */ + struct sock; struct inet_skb_parm { 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) |