net: mscc: ocelot: deal with problematic MAC_ETYPE VCAP IS2 rules

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By default, the VCAP IS2 will produce a single match for each frame, on
the most specific classification.

Example: a ping packet (ICMP over IPv4 over Ethernet) sent from an IP
address of 10.0.0.1 and a MAC address of 96:18:82:00:04:01 will match
this rule:

tc filter add dev swp0 ingress protocol ipv4 \
	flower skip_sw src_ip 10.0.0.1 action drop

but not this one:

tc filter add dev swp0 ingress \
	flower skip_sw src_mac 96:18:82:00:04:01 action drop

Currently the driver does not really warn the user in any way about
this, and the behavior is rather strange anyway.

The current patch is a workaround to force matches on MAC_ETYPE keys
(DMAC and SMAC) for all packets irrespective of higher layer protocol.
The setting is made at the port level.

Of course this breaks all other non-src_mac and non-dst_mac matches, so
rule exclusivity checks have been added to the driver, in order to never
have rules of both types on any ingress port.

The bits that discard higher-level protocol information are set only
once a MAC_ETYPE rule is added to a filter block, and only for the ports
that are bound to that filter block. Then all further non-MAC_ETYPE
rules added to that filter block should be denied by the ports bound to
it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

This commit is contained in:

Vladimir Oltean 2020-04-17 22:03:08 +03:00 • committed by David S. Miller

parent f89370d413

commit 89f9ffd3eb

3 changed files with 106 additions and 4 deletions

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103

drivers/net/ethernet/mscc/ocelot_ace.c

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5

drivers/net/ethernet/mscc/ocelot_ace.h

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2

drivers/net/ethernet/mscc/ocelot_flower.c

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