Re: [patch net-next RFC 2/2] flow_dissecror: Move MPLS dissection into a separate function

[Simon Horman]

On Tue, Feb 21, 2017 at 03:33:19PM +0100, Jiri Pirko wrote:
> From: Jiri Pirko 
> 
> Make the main flow_dissect function a bit smaller and move the MPLS
> dissection into a separate function. Along with that, do the MPLS header
> processing only in case the flow dissection user requires it.
> 
> Signed-off-by: Jiri Pirko 

Reviewed-by: Simon Horman 

[patch net-next RFC 2/2] flow_dissecror: Move MPLS dissection into a separate function

[Jiri Pirko]

From: Jiri Pirko 

Make the main flow_dissect function a bit smaller and move the MPLS
dissection into a separate function. Along with that, do the MPLS header
processing only in case the flow dissection user requires it.

Signed-off-by: Jiri Pirko 
---
 net/core/flow_dissector.c | 52 ---
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 10dc5bb..3ab935e 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -113,6 +113,33 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int 
thoff, u8 ip_proto,
 }
 EXPORT_SYMBOL(__skb_flow_get_ports);
 
+static bool __skb_flow_dissect_mpls(const struct sk_buff *skb,
+   struct flow_dissector *flow_dissector,
+   void *target_container, void *data,
+   int nhoff, int hlen)
+{
+   struct flow_dissector_key_keyid *key_keyid;
+   struct mpls_label *hdr, _hdr[2];
+
+   if (!dissector_uses_key(flow_dissector,
+   FLOW_DISSECTOR_KEY_MPLS_ENTROPY))
+   return true;
+
+   hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
+  hlen, &_hdr);
+   if (!hdr)
+   return false;
+
+   if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
+   MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
+   key_keyid = skb_flow_dissector_target(flow_dissector,
+ 
FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
+ target_container);
+   key_keyid->keyid = hdr[1].entry & htonl(MPLS_LS_LABEL_MASK);
+   }
+   return true;
+}
+
 static bool __skb_flow_dissect_arp(const struct sk_buff *skb,
   struct flow_dissector *flow_dissector,
   void *target_container, void *data,
@@ -403,30 +430,13 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
}
 
case htons(ETH_P_MPLS_UC):
-   case htons(ETH_P_MPLS_MC): {
-   struct mpls_label *hdr, _hdr[2];
+   case htons(ETH_P_MPLS_MC):
 mpls:
-   hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
-  hlen, &_hdr);
-   if (!hdr)
+   if (!__skb_flow_dissect_mpls(skb, flow_dissector,
+target_container, data,
+nhoff, hlen))
goto out_bad;
-
-   if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
-MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
-   if (dissector_uses_key(flow_dissector,
-  
FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
-   key_keyid = 
skb_flow_dissector_target(flow_dissector,
- 
FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
- 
target_container);
-   key_keyid->keyid = hdr[1].entry &
-   htonl(MPLS_LS_LABEL_MASK);
-   }
-
-   goto out_good;
-   }
-
goto out_good;
-   }
 
case htons(ETH_P_FCOE):
if ((hlen - nhoff) < FCOE_HEADER_LEN)
-- 
2.7.4