flow_dissector: Move MPLS dissection into a separate function

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 <jiri@mellanox.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 d79fb8f8f033fab11b5df04b52a0d56efec18c1a..8d012987e3c364faaa93306a58a714004da7585c 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -118,6 +118,33 @@ enum flow_dissect_ret {
        FLOW_DISSECT_RET_OUT_BAD,
 };
 
+static enum flow_dissect_ret
+__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 FLOW_DISSECT_RET_OUT_GOOD;
+
+       hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
+                                  hlen, &_hdr);
+       if (!hdr)
+               return FLOW_DISSECT_RET_OUT_BAD;
+
+       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 FLOW_DISSECT_RET_OUT_GOOD;
+}
+
 static enum flow_dissect_ret
 __skb_flow_dissect_arp(const struct sk_buff *skb,
                       struct flow_dissector *flow_dissector,
@@ -408,31 +435,16 @@ ipv6:
        }
 
        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)
-                       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);
-                       }
-
+               switch (__skb_flow_dissect_mpls(skb, flow_dissector,
+                                               target_container, data,
+                                               nhoff, hlen)) {
+               case FLOW_DISSECT_RET_OUT_GOOD:
                        goto out_good;
+               case FLOW_DISSECT_RET_OUT_BAD:
+                       goto out_bad;
                }
-
-               goto out_good;
-       }
-
        case htons(ETH_P_FCOE):
                if ((hlen - nhoff) < FCOE_HEADER_LEN)
                        goto out_bad;