session: Interface to query session->mark value

Will return the session mark (without needing to expose the complete
struct connman_session).
diff --git a/include/session.h b/include/session.h
index 0d66f48..5106e88 100644
--- a/include/session.h
+++ b/include/session.h
@@ -22,6 +22,7 @@
 #ifndef __CONNMAN_SESSION_H
 #define __CONNMAN_SESSION_H
 
+#include <stdint.h>
 #include <connman/service.h>
 
 #ifdef __cplusplus
@@ -97,6 +98,7 @@
 							   GSList* services);
 };
 
+uint32_t connman_session_firewall_get_fwmark(struct connman_session *session);
 int connman_session_policy_register(struct connman_session_policy *config);
 void connman_session_policy_unregister(struct connman_session_policy *config);
 
diff --git a/src/session.c b/src/session.c
index 92781df..9dd183f 100644
--- a/src/session.c
+++ b/src/session.c
@@ -436,6 +436,11 @@
 	g_free(ifname);
 }
 
+uint32_t connman_session_firewall_get_fwmark(struct connman_session *session)
+{
+	return session->mark;
+}
+
 static void cleanup_routing_table(struct connman_session *session)
 {
 	DBG("");