flow_dissector: Add flag to stop parsing at L3

Add an input flag to flow dissector on rather dissection should be
stopped when an L3 packet is encountered. This would be useful if a
caller just wanted to get IP addresses of the outermost header (e.g.
to do an L3 hash).

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 34102270b0862af9fffd3f4a8b92b3179681931c..bb81e3b576e709272a40efd0948de44915f7bce3 100644 (file)
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -125,6 +125,7 @@ enum flow_dissector_key_id {
 };
 
 #define FLOW_DISSECTOR_F_PARSE_1ST_FRAG                BIT(0)
+#define FLOW_DISSECTOR_F_STOP_AT_L3            BIT(1)
 
 struct flow_dissector_key {
        enum flow_dissector_key_id key_id;

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 907de2f68b1fca7dc4b298f8f55f7b7570548d0c..94fd841f341f16fd0d4476ee52f28bfde29909dc 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -200,6 +200,9 @@ ip:
                        }
                }
 
+               if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
+                       goto out_good;
+
                break;
        }
        case htons(ETH_P_IPV6): {
@@ -238,6 +241,9 @@ ipv6:
                        }
                }
 
+               if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
+                       goto out_good;
+
                break;
        }
        case htons(ETH_P_8021AD):