From: Stephen Hemminger <stephen@networkplumber•org>
To: Daniel Borkmann <dborkman@redhat•com>
Cc: davem@davemloft•net, shahed.shaikh@qlogic•com, netdev@vger•kernel.org
Subject: Re: [PATCH net-next] net: vxlan: use custom ndo_change_mtu handler
Date: Tue, 17 Dec 2013 09:36:40 -0800 [thread overview]
Message-ID: <20131217093640.63220542@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <1387286409-1783-1-git-send-email-dborkman@redhat.com>
On Tue, 17 Dec 2013 14:20:09 +0100
Daniel Borkmann <dborkman@redhat•com> wrote:
> +static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
> +{
> + struct net *net = current->nsproxy->net_ns;
> + struct vxlan_dev *vxlan = netdev_priv(dev);
> + struct vxlan_rdst *dst = &vxlan->default_dst;
> + bool is_ipv6 = dst->remote_ip.sa.sa_family == AF_INET6;
> + int hroom = is_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM;
> + struct net_device *lowerdev;
> +
> + lowerdev = dev_get_by_index(net, dst->remote_ifindex);
> + if (lowerdev == NULL)
> + return eth_change_mtu(dev, new_mtu);
> +
> + if (new_mtu == lowerdev->mtu)
> + new_mtu = lowerdev->mtu - hroom;
> + if (new_mtu < 68 || new_mtu > lowerdev->mtu - hroom) {
> + dev_put(lowerdev);
> + return -EINVAL;
> + }
> +
> + dev->mtu = new_mtu;
> +
> + dev_put(lowerdev);
> + return 0;
> +}
> +
The *net should just be devnet(dev).
Don't need ref here, called under RTNL.
You can't arbitrarly shrink user's requested mtu
Minor nit picking: I don't like adding more local flag variables.
To me it is clearer.
The resulting function is:
static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
{
struct vxlan_dev *vxlan = netdev_priv(dev);
int maxmtu;
struct net_device *lowerdev;
lowerdev = __dev_get_by_index(devnet(dev),
vxlan->default_dst.remote_ifindex);
if (lowerdev == NULL)
return eth_change_mtu(dev, new_mtu);
if (dst->remote_ip.sa.sa_family == AF_INET6)
maxmtu = lowerdev->mtu - VXLAN6_HEADROOM;
else
maxmtu = lowerdev->mtu - VXLAN_HEADROOM;
if (new_mtu < 68 || new_mtu > maxmtu)
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
next prev parent reply other threads:[~2013-12-17 17:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 13:20 [PATCH net-next] net: vxlan: use custom ndo_change_mtu handler Daniel Borkmann
2013-12-17 17:36 ` Stephen Hemminger [this message]
2013-12-17 18:18 ` Daniel Borkmann
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