Re: [PATCH net] net: ethtool: Allow matching on vlan CFI bit

From: Toshiaki Makita
Date: Wed Jun 12 2019 - 02:36:36 EST

On 2019/06/12 0:54, Maxime Chevallier wrote:
Using ethtool, users can specify a classification action matching on the
full vlan tag, which includes the CFI bit.

However, when converting the ethool_flow_spec to a flow_rule, we use
dissector keys to represent the matching patterns.

Since the vlan dissector key doesn't include the CFI bit, this
information was silently discarded when translating the ethtool
flow spec in to a flow_rule.

This commit adds the CFI bit into the vlan dissector key, and allows
propagating the information to the driver when parsing the ethtool flow

Fixes: eca4205f9ec3 ("ethtool: add ethtool_rx_flow_spec to flow_rule structure translator")
Reported-by: MichaÅ MirosÅaw <mirq-linux@xxxxxxxxxxxx>
Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
Hi all,

Although this prevents information to be silently discarded when parsing
an ethtool_flow_spec, this information doesn't seem to be used by any
driver that converts an ethtool_flow_spec to a flow_rule, hence I'm not
sure this is suitable for -net.



include/net/flow_dissector.h | 1 +
net/core/ethtool.c | 5 +++++
2 files changed, 6 insertions(+)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 7c5a8d9a8d2a..9d2e395c6568 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -46,6 +46,7 @@ struct flow_dissector_key_tags {
struct flow_dissector_key_vlan {
u16 vlan_id:12,
+ vlan_cfi:1,

Current IEEE 802.1Q defines this bit as DEI not CFI, so IMO this should be

Toshiaki Makita