> On Mon, Jan 8, 2018 at 10:48 PM, <liuq...@huawei.com> wrote:
> > From: Keefe Liu <liuq...@huawei.com>
> >
> > The MTU of ipvlan interface should not bigger than the phy device,
> > When we run following scripts, we will find there are some problems.
> > Step1:
> > ip link add link eth0 name ipv1 type ipvlan mode l2
> > ip netns add net1
> > ip link set dev ipv1 netns net1
> > Step2:
> > ip netns exec net1 ip link set dev ipv1 mtu 1501
> > RTNETLINK answers: Invalid argument
> > dmesg info: "ipv1: Invalid MTU 1501 requested, hw max 1500"
> > Step3:
> > ip link set dev eth0 mtu 1600
> > ip netns exec net1 ip link set dev ipv1 mtu 1501
> > RTNETLINK answers: Invalid argument
> > dmesg info: "ipv1: Invalid MTU 1501 requested, hw max 1500"
> > Step4:
> > ip link set dev eth0 mtu 1400
> > ip netns exec net1 ip link set dev ipv1 mtu 1500 The result of
> > Step2 is we expected, but the result of Step3 and Step4 are not.
> >
> > This patch set ipvlan's maximum MTU to ETH_MAX_MTU, and when we
> change
> > the ipvlan device's MTU, ipvlan_change_mtu() will make sure the new
> > MTU no larger than the phy device's MTU.
> >
> > Signed-off-by: Keefe Liu <liuq...@huawei.com>
> > ---
> > drivers/net/ipvlan/ipvlan_main.c | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/net/ipvlan/ipvlan_main.c
> > b/drivers/net/ipvlan/ipvlan_main.c
> > index 30cb803..84c007d 100644
> > --- a/drivers/net/ipvlan/ipvlan_main.c
> > +++ b/drivers/net/ipvlan/ipvlan_main.c
> > @@ -380,12 +380,24 @@ static int ipvlan_get_iflink(const struct net_device
> *dev)
> > return ipvlan->phy_dev->ifindex; }
> >
> > +static int ipvlan_change_mtu(struct net_device *dev, int new_mtu) {
> > + struct ipvl_dev *ipvlan = netdev_priv(dev);
> > +
> > + if (ipvlan->phy_dev->mtu < new_mtu)
> > + return -EINVAL;
> > +
> > + dev->mtu = new_mtu;
> > + return 0;
> > +}
> > +
> > static const struct net_device_ops ipvlan_netdev_ops = {
> > .ndo_init = ipvlan_init,
> > .ndo_uninit = ipvlan_uninit,
> > .ndo_open = ipvlan_open,
> > .ndo_stop = ipvlan_stop,
> > .ndo_start_xmit = ipvlan_start_xmit,
> > + .ndo_change_mtu = ipvlan_change_mtu,
> > .ndo_fix_features = ipvlan_fix_features,
> > .ndo_change_rx_flags = ipvlan_change_rx_flags,
> > .ndo_set_rx_mode = ipvlan_set_multicast_mac_filter,
> > @@ -680,6 +692,8 @@ void ipvlan_link_setup(struct net_device *dev) {
> > ether_setup(dev);
> >
> > + dev->min_mtu = 0;
> should be ETH_MIN_MTU since we expect the underlying device to be
> ETH_ARPHDR and IPvlan deals with IPv4/IPv6.
>
[liuqifa] Yes, I agree with you. But I have another question, I found in commit
9157208, macvlan's min_mtu has been changed from ETH_MIN_MTU to 0, I'd like to
know what's the difference between macvlan and ipvlan.
> > + dev->max_mtu = ETH_MAX_MTU;
> > dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
> > dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
> > dev->netdev_ops = &ipvlan_netdev_ops;
> > --
> > 1.8.3.1
> >
> >
> These changes are not sufficient if you want to have different per-slave mtu
> settings. One can always change the MTU of the master device and all per-
> slave settings will get wiped. I don't think that's a desired outcome.
[liuqifa] I agree with you, I will reprogram the code to realize this goal.
