net: make skb an optional parameter for__skb_flow_dissect()

Fixes: commit 690e36e726d00d2 (net: Allow raw buffers to be passed into the flow dissector)
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 3 deletions

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index ae8f0db67aed..12f48ca7a0b0 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -59,14 +59,26 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
 }
 EXPORT_SYMBOL(__skb_flow_get_ports);
 
-bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow, void *data, int hlen)
+/**
+ * __skb_flow_dissect - extract the flow_keys struct and return it
+ * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
+ * @data: raw buffer pointer to the packet, if NULL use skb->data
+ * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
+ * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
+ * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
+ *
+ * The function will try to retrieve the struct flow_keys from either the skbuff
+ * or a raw buffer specified by the rest parameters
+ */
+bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow,
+                        void *data, __be16 proto, int nhoff, int hlen)
 {
-        int nhoff = skb_network_offset(skb);
         u8 ip_proto;
-        __be16 proto = skb->protocol;
 
         if (!data) {
                 data = skb->data;
+                proto = skb->protocol;
+                nhoff = skb_network_offset(skb);
                 hlen = skb_headlen(skb);
         }