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.
