Users of the NXP LS1028A SoC (drivers/net/dsa/ocelot L2 switch inside)
have requested to mirror packets from the ingress of a switch port to
software. Both port-based and flow-based mirroring is required.
The simplest way I could come up with was to set up tc mirred actions
towards a dummy net_device, and make the offloading of that be accepted
by the driver. Currently, the pattern in drivers is to reject mirred
towards ports they don't know about, but I'm now permitting that,
precisely by mirroring "to the CPU".
For testers, this series depends on the following bug fix:
https://lore.kernel.org/netdev/20241017161049.3570037-1-vladimir.oltean@nxp.com/
otherwise it is possible to create invalid combinations which are not
rejected.
Changes from RFC:
- Sent the bug fix separately, now merged as commit 8c924369cb56 ("net:
dsa: refuse cross-chip mirroring operations") in the "net" tree
- Allow mirroring to the ingress of another switch port (using software)
both for matchall in DSA and flower offload in ocelot
- Patch 3/6 is new
Link to previous RFC:
https://lore.kernel.org/netdev/20240913152915.2981126-1-vladimir.oltean@nxp.com/
For historical purposes, link to a much older (and much different) attempt:
https://lore.kernel.org/netdev/20191002233750.13566-1-olteanv@gmail.com/
Vladimir Oltean (6):
net: sched: propagate "skip_sw" flag to offload for flower and
matchall
net: dsa: clean up dsa_user_add_cls_matchall()
net: dsa: use "extack" as argument to
flow_action_basic_hw_stats_check()
net: dsa: add more extack messages in
dsa_user_add_cls_matchall_mirred()
net: dsa: allow matchall mirroring rules towards the CPU
net: mscc: ocelot: allow tc-flower mirred action towards foreign
interfaces
drivers/net/ethernet/mscc/ocelot_flower.c | 54 ++++++++++++----
include/net/flow_offload.h | 1 +
include/net/pkt_cls.h | 1 +
net/dsa/user.c | 78 +++++++++++++++++------
net/sched/cls_flower.c | 1 +
net/sched/cls_matchall.c | 1 +
6 files changed, 105 insertions(+), 31 deletions(-)
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2.43.0