On 01/07/16 at 08:35am, Jesse Gross wrote: > On Thu, Jan 7, 2016 at 3:49 AM, Thomas Graf <tg...@suug.ch> wrote: > > A simple start could be to add a new return code for > MTU drops in > > the dev_queue_xmit() path and check for NET_XMIT_DROP_MTU in > > ovs_vport_send() and emit proper ICMPs. > > That could be interesting. The problem in the past was making sure > that ICMPs that are generated fit in the virtual network appropriately > - right addresses, etc. This requires either spoofing addresses or > some additional knowledge about the topology that we don't currently > have in the kernel.
Are you worried about emitting an ICMP with a source which is not a local host address? Can't we just use icmp_send() in the context of the inner header and feed it to the flow table to send it back? It should be the same as for ip_forward(). skb->dev or skb->dst should lead us to the real MTU which can be included in the ICMP frag needed. It's a bit tricky because we would have to know whether it was encapsulated or not and adjust accordingly. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
