flow_dissector: Fix handling of mixed port and port-range keys

flow_dissector: Fix handling of mixed port and port-range keys

This patch fixes a bug in TC flower filter where rules combining a
specific destination port with a source port range weren't working
correctly.

The specific case was when users tried to configure rules like:

tc filter add dev ens38 ingress protocol ip flower ip_proto udp \
dst_port 5000 src_port 2000-3000 action drop

The root cause was in the flow dissector code. While both
FLOW_DISSECTOR_KEY_PORTS and FLOW_DISSECTOR_KEY_PORTS_RANGE flags
were being set correctly in the classifier, the __skb_flow_dissect_ports()
function was only populating one of them: whichever came first in
the enum check. This meant that when the code needed both a specific
port and a port range, one of them would be left as 0, causing the
filter to not match packets as expected.

Fix it by removing the either/or logic and instead checking and
populating both key types independently when they're in use.

Fixes: 8ffb055beae5 ("cls_flower: Fix the behavior using port ranges with hw-offload")
Reported-by: Qiang Zhang <dtzq01@gmail.com>
Closes: https://lore.kernel.org/netdev/CAPx+-5uvFxkhkz4=j_Xuwkezjn9U6kzKTD5jz4tZ9msSJ0fOJA@mail.gmail.com/
Cc: Yoshiki Komachi <komachi.yoshiki@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250218043210.732959-2-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>