On Wed, 11 Nov 2020 20:37:28 +0100 Pablo Neira Ayuso wrote: > The following patchset augments the Netfilter flowtable fastpath [1] to > support for network topologies that combine IP forwarding, bridge and > VLAN devices. > > A typical scenario that can benefit from this infrastructure is composed > of several VMs connected to bridge ports where the bridge master device > 'br0' has an IP address. A DHCP server is also assumed to be running to > provide connectivity to the VMs. The VMs reach the Internet through > 'br0' as default gateway, which makes the packet enter the IP forwarding > path. Then, netfilter is used to NAT the packets before they leave > through the wan device. > > Something like this: > > fast path > .------------------------. > / \ > | IP forwarding | > | / \ . > | br0 eth0 > . / \ > -- veth1 veth2 > . > . > . > eth0 > ab:cd:ef:ab:cd:ef > VM > > The idea is to accelerate forwarding by building a fast path that takes > packets from the ingress path of the bridge port and place them in the > egress path of the wan device (and vice versa). Hence, skipping the > classic bridge and IP stack paths. The problem that immediately comes to mind is that if there is any dynamic forwarding state the cache you're creating would need to be flushed when FDB changes. Are you expecting users would plug into the flowtable devices where they know things are fairly static?
