ip6_tunnel: use the right value for ipv4 min mtu check in ip6_tnl_xmit
authorXin Long <lucien.xin@gmail.com>
Sun, 5 Aug 2018 14:46:07 +0000 (22:46 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 22 Aug 2018 05:46:09 +0000 (07:46 +0200)
commitb3fb9398723238f39e3ff0c9c7f0d1cadf04738a
tree8da2d3e1262b8969595a030bd624fa09bd6cad8a
parent59f9f2c76fe16026f293d87ae6001f80ccab420b
ip6_tunnel: use the right value for ipv4 min mtu check in ip6_tnl_xmit

[ Upstream commit 82a40777de12728dedf4075453b694f0d1baee80 ]

According to RFC791, 68 bytes is the minimum size of IPv4 datagram every
device must be able to forward without further fragmentation while 576
bytes is the minimum size of IPv4 datagram every device has to be able
to receive, so in ip6_tnl_xmit(), 68(IPV4_MIN_MTU) should be the right
value for the ipv4 min mtu check in ip6_tnl_xmit.

While at it, change to use max() instead of if statement.

Fixes: c9fefa08190f ("ip6_tunnel: get the min mtu properly in ip6_tnl_xmit")
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/ipv6/ip6_tunnel.c