Re: [PATCH net-next v8 1/2] net/sched: cls_flower: remove unions from fl_flow_key
From: Simon Horman <horms@kernel.org>
Date: 2026-03-13 13:26:56
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On Wed, Mar 11, 2026 at 11:46:18AM +0100, Cedric Jehasse via B4 Relay wrote:
From: Cedric Jehasse <redacted>
When creating a flower classifier with an ipv4 address the
flow_dissector has both FLOW_DISSECTOR_KEY_IPV4_ADDRS and
FLOW_DISSECTOR_KEY_IPV6_ADDRS bits set in used_keys.
This happens because ipv4/ipv6 fields are a union and
FL_KEY_SET_IF_MASKED() will interpret either being set as both.
Removing the unions fixes this behavior without needing special handling
for union fields.
Example of a command that caused FLOW_DISSECTOR_KEY_IPV4_ADDRS and
FLOW_DISSECTOR_KEY_IPV6_ADDRS to be set:
tc filter add dev p1 ingress protocol ip flower skip_sw \
dst_ip 224.0.1.129 action trap
Signed-off-by: Cedric Jehasse <redacted>Hi Cedric, This doesn't seem to be the right approach to me. It seems to me that the use of a union is intentional here, as either IPv4 or IPv6 addresses can be present in each case - never both. And that control.addr_type and enc_control.addr_type are intended to allow differentiation of the address type in use for each of these unions.
quoted hunk ↗ jump to hunk
--- net/sched/cls_flower.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 7669371c1354..b95dbe847dde 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c@@ -59,18 +59,14 @@ struct fl_flow_key { struct flow_dissector_key_eth_addrs eth; struct flow_dissector_key_vlan vlan; struct flow_dissector_key_vlan cvlan; - union { - struct flow_dissector_key_ipv4_addrs ipv4; - struct flow_dissector_key_ipv6_addrs ipv6; - }; + struct flow_dissector_key_ipv4_addrs ipv4; + struct flow_dissector_key_ipv6_addrs ipv6; struct flow_dissector_key_ports tp; struct flow_dissector_key_icmp icmp; struct flow_dissector_key_arp arp; struct flow_dissector_key_keyid enc_key_id; - union { - struct flow_dissector_key_ipv4_addrs enc_ipv4; - struct flow_dissector_key_ipv6_addrs enc_ipv6; - }; + struct flow_dissector_key_ipv4_addrs enc_ipv4; + struct flow_dissector_key_ipv6_addrs enc_ipv6; struct flow_dissector_key_ports enc_tp; struct flow_dissector_key_mpls mpls; struct flow_dissector_key_tcp tcp;-- 2.43.0