payload: add payload_is_stacked()

Add payload_is_stacked() to determine whether a protocol expression match defines
a stacked protocol on the same layer.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/payload.h b/include/payload.h
index eb9ff17d..b180ff53 100644
--- a/include/payload.h
+++ b/include/payload.h
@@ -30,6 +30,8 @@ struct payload_dep_ctx {
 	struct stmt		*prev;
 };
 
+extern bool payload_is_stacked(const struct proto_desc *desc,
+			       const struct expr *expr);
 extern void payload_dependency_store(struct payload_dep_ctx *ctx,
 				     struct stmt *stmt,
 				     enum proto_bases base);