Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-17 Thread Daniel Axtens
Hi Dave, > So how exactly do the oversized packets get to the macvlan device from > the VM in this scenerio? That detail seems to be missing from the > diagrams you provided earlier. The VM and the macvlan boxes are just > connected with a line. Inside the VM I'm using netperf talking on an

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-17 Thread David Miller
From: Daniel Axtens Date: Fri, 17 Nov 2017 19:34:27 +1100 > Hi Dave, > >> This is an area where we really haven't set down some clear rules >> for behavior. >> >> If an interface has a particular MTU, it must be able to successfully >> send MTU sized packets on that link be it

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-17 Thread Daniel Axtens
Hi Dave, > This is an area where we really haven't set down some clear rules > for behavior. > > If an interface has a particular MTU, it must be able to successfully > send MTU sized packets on that link be it virtual or physical. > > Only a "next hop" can have a different MTU and thus drop

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-16 Thread David Miller
From: Daniel Axtens Date: Tue, 14 Nov 2017 21:32:51 +1100 > If a macvlan device which is not in bridge mode receives a packet, > it is sent straight to the lowerdev without checking against the > device's MTU. This also happens for multicast traffic. > > Add an

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-14 Thread Daniel Axtens
Hi Shannon, > Now that I think about this a little more, why is this not already > getting handled by the NETDEV_CHANGEMTU notifier? In what case are you > running into this, and why is it not triggering the notifier? My commit message was probably not super clear here - apologies for any

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-14 Thread Shannon Nelson
On 11/14/2017 9:03 AM, Shannon Nelson wrote: On 11/14/2017 2:32 AM, Daniel Axtens wrote: If a macvlan device which is not in bridge mode receives a packet, it is sent straight to the lowerdev without checking against the device's MTU. This also happens for multicast traffic. Add an

Re: [PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-14 Thread Shannon Nelson
On 11/14/2017 2:32 AM, Daniel Axtens wrote: If a macvlan device which is not in bridge mode receives a packet, it is sent straight to the lowerdev without checking against the device's MTU. This also happens for multicast traffic. Add an is_skb_forwardable() check against the lowerdev before

[PATCH] macvlan: verify MTU before lowerdev xmit

2017-11-14 Thread Daniel Axtens
If a macvlan device which is not in bridge mode receives a packet, it is sent straight to the lowerdev without checking against the device's MTU. This also happens for multicast traffic. Add an is_skb_forwardable() check against the lowerdev before sending the packet out through it. I think this