diff --git a/pimd/pim_assert.h b/pimd/pim_assert.h
index feeb91d..bd3fb3e 100644
--- a/pimd/pim_assert.h
+++ b/pimd/pim_assert.h
@@ -51,7 +51,7 @@
 int pim_assert_recv(struct interface *ifp,
 		    struct pim_neighbor *neigh,
 		    struct in_addr src_addr,
-		    char *buf, int buf_size);
+		    uint8_t *buf, int buf_size);
 
 int pim_assert_metric_better(const struct pim_assert_metric *m1,
 			     const struct pim_assert_metric *m2);