netdev - [RESEND]tc-flower not worked when configured dst_port and src

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Message-ID: <CAPx+-5uvFxkhkz4=j_Xuwkezjn9U6kzKTD5jz4tZ9msSJ0fOJA@mail.gmail.com>
Date: Fri, 14 Feb 2025 17:00:30 +0800
From: Qiang Zhang <dtzq01@...il.com>
To: Jamal Hadi Salim <jhs@...atatu.com>, Cong Wang <xiyou.wangcong@...il.com>, 
	Jiri Pirko <jiri@...nulli.us>, stable@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org, 
	regressions@...ts.linux.dev
Subject: [RESEND]tc-flower not worked when configured dst_port and src_port
 range in one rule.

Hi, all.

recently met an issue: tc-flower not worked when configured dst_port
and src_port range in one rule.

detailed like this:
$ tc qdisc add dev ens38 ingress
$ tc filter add dev ens38 ingress protocol ip flower ip_proto udp \
  dst_port 5000 src_port 2000-3000 action drop

I try to find the root cause in kernel source code:
1. FLOW_DISSECTOR_KEY_PORTS and FLOW_DISSECTOR_KEY_PORTS_RANGE flag of
mask->dissector were set
in fl_classify from flow_dissector.c.
2. then skb_flow_dissect -> __skb_flow_dissect -> __skb_flow_dissect_ports.
3. FLOW_DISSECTOR_KEY_PORTS handled and FLOW_DISSECTOR_KEY_PORTS_RANGE
not handled
in __skb_flow_dissect_ports, so tp_range.tp.src was 0 here expected
the actual skb source port.

By the way, __skb_flow_bpf_to_target function may has the same issue.

Please help confirm and fix it, thank you.

source code of __skb_flow_dissect_ports in flow_dissector.c as below:

static void
__skb_flow_dissect_ports(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container, const void *data,
int nhoff, u8 ip_proto, int hlen)
{
enum flow_dissector_key_id dissector_ports = FLOW_DISSECTOR_KEY_MAX;
struct flow_dissector_key_ports *key_ports;

if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS))
dissector_ports = FLOW_DISSECTOR_KEY_PORTS;
else if (dissector_uses_key(flow_dissector,
   FLOW_DISSECTOR_KEY_PORTS_RANGE))
dissector_ports = FLOW_DISSECTOR_KEY_PORTS_RANGE;

if (dissector_ports == FLOW_DISSECTOR_KEY_MAX)
return;

key_ports = skb_flow_dissector_target(flow_dissector,
     dissector_ports,
     target_container);
key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
data, hlen);
}

Best regards.