archive mirror
 help / color / mirror / Atom feed
From: David Miller <>
Subject: Re: [PATCH net-next] net: dsa: Allow port mirroring to the CPU port
Date: Thu, 03 Oct 2019 12:04:57 -0700 (PDT)	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

From: Vladimir Oltean <>
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 <>

Andrew and co., please review.

  reply	other threads:[~2019-10-03 19:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 23:37 Vladimir Oltean
2019-10-03 19:04 ` David Miller [this message]
2019-10-03 19:09   ` Andrew Lunn
2019-10-03 19:24 ` Andrew Lunn
2019-10-03 21:21   ` Vladimir Oltean

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \
    --subject='Re: [PATCH net-next] net: dsa: Allow port mirroring to the CPU port' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).