flow_dissector: factor out the ports extraction in skb_flow_get_ports
Factor out the code that extracts the ports from skb_flow_dissect and
add a new function skb_flow_get_ports which can be re-used.
Suggested-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 8d7d0dd..f8e25ac 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -25,9 +25,35 @@
memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst));
}
+/**
+ * skb_flow_get_ports - extract the upper layer ports and return them
+ * @skb: buffer to extract the ports from
+ * @thoff: transport header offset
+ * @ip_proto: protocol for which to get port offset
+ *
+ * The function will try to retrieve the ports at offset thoff + poff where poff
+ * is the protocol port offset returned from proto_ports_offset
+ */
+__be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto)
+{
+ int poff = proto_ports_offset(ip_proto);
+
+ if (poff >= 0) {
+ __be32 *ports, _ports;
+
+ ports = skb_header_pointer(skb, thoff + poff,
+ sizeof(_ports), &_ports);
+ if (ports)
+ return *ports;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(skb_flow_get_ports);
+
bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
{
- int poff, nhoff = skb_network_offset(skb);
+ int nhoff = skb_network_offset(skb);
u8 ip_proto;
__be16 proto = skb->protocol;
@@ -150,16 +176,7 @@
}
flow->ip_proto = ip_proto;
- poff = proto_ports_offset(ip_proto);
- if (poff >= 0) {
- __be32 *ports, _ports;
-
- ports = skb_header_pointer(skb, nhoff + poff,
- sizeof(_ports), &_ports);
- if (ports)
- flow->ports = *ports;
- }
-
+ flow->ports = skb_flow_get_ports(skb, nhoff, ip_proto);
flow->thoff = (u16) nhoff;
return true;