Commit 2fa771be authored Dec 25, 2017 by Xin Long Committed by David S. Miller Jan 02, 2018

ip6_tunnel: allow ip6gre dev mtu to be set below 1280



Commit 582442d6 ("ipv6: Allow the MTU of ipip6 tunnel to be set
below 1280") fixed a mtu setting issue. It works for ipip6 tunnel.

But ip6gre dev updates the mtu also with ip6_tnl_change_mtu. Since
the inner packet over ip6gre can be ipv4 and it's mtu should also
be allowed to set below 1280, the same issue also exists on ip6gre.

This patch is to fix it by simply changing to check if parms.proto
is IPPROTO_IPV6 in ip6_tnl_change_mtu instead, to make ip6gre to
go to 'else' branch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 52a589d5

net/ipv6/ip6_tunnel.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1677,11 +1677,11 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
		{
		struct ip6_tnl *tnl = netdev_priv(dev);

		if (tnl->parms.proto == IPPROTO_IPIP) {
		if (new_mtu < ETH_MIN_MTU)
		if (tnl->parms.proto == IPPROTO_IPV6) {
		if (new_mtu < IPV6_MIN_MTU)
		return -EINVAL;
		} else {
		if (new_mtu < IPV6_MIN_MTU)
		if (new_mtu < ETH_MIN_MTU)
		return -EINVAL;
		}
		if (new_mtu > 0xFFF8 - dev->hard_header_len)

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