From: Vladimir Oltean <olte...@gmail.com> Date: Thu, 3 Oct 2019 02:37:50 +0300
> On a regular netdev, putting it in promiscuous mode means receiving all > traffic passing through it, whether or not it was destined to its MAC > address. Then monitoring applications such as tcpdump can see all > traffic transiting it. > > On Ethernet switches, clearly all ports are in promiscuous mode by > definition, since they accept frames destined to any MAC address. > However tcpdump does not capture all frames transiting switch ports, > only the ones destined to, or originating from the CPU port. > > To be able to monitor frames with tcpdump on the CPU port, extend the tc > matchall classifier and mirred action to support the DSA master port as > a possible mirror target. > > Tested with: > tc qdisc add dev swp2 clsact > tc filter add dev swp2 ingress matchall skip_sw \ > action mirred egress mirror dev eth2 > tcpdump -i swp2 > > Signed-off-by: Vladimir Oltean <olte...@gmail.com> Andrew and co., please review.
