Add context id getter to TKM DH implementation

src/charon-tkm/src/tkm/tkm_diffie_hellman.c

@@ -103,6 +103,12 @@ METHOD(diffie_hellman_t, destroy, void,
 	free(this);
 }
 
+METHOD(tkm_diffie_hellman_t, get_id, dh_id_type,
+	private_tkm_diffie_hellman_t *this)
+{
+	return this->context_id;
+}
+
 /*
  * Described in header.
  */
@@ -119,6 +125,7 @@ tkm_diffie_hellman_t *tkm_diffie_hellman_create(diffie_hellman_group_t group)
 				.get_dh_group = _get_dh_group,
 				.destroy = _destroy,
 			},
+			.get_id = _get_id,
 		},
 		.group = group,
 		.context_id = tkm->idmgr->acquire_id(tkm->idmgr, TKM_CTX_DH),

src/charon-tkm/src/tkm/tkm_diffie_hellman.h

@@ -20,6 +20,7 @@
 typedef struct tkm_diffie_hellman_t tkm_diffie_hellman_t;
 
 #include <library.h>
+#include <tkm/types.h>
 
 /**
  * diffie_hellman_t implementation using the trusted key manager.
@@ -30,6 +31,14 @@ struct tkm_diffie_hellman_t {
 	 * Implements diffie_hellman_t interface.
 	 */
 	diffie_hellman_t dh;
+
+	/**
+	 * Get Diffie-Hellman context id.
+	 *
+	 * @return	id of this DH context.
+	 */
+	dh_id_type (*get_id)(tkm_diffie_hellman_t * const this);
+
 };
 
 /**

src/charon-tkm/tests/diffie_hellman_tests.c

@@ -27,6 +27,7 @@ START_TEST(test_dh_creation)
 
 	dh = tkm_diffie_hellman_create(MODP_4096_BIT);
 	fail_if(!dh, "MODP_4096 not created");
+	fail_if(!dh->get_id(dh), "Invalid context id (0)");
 
 	dh->dh.destroy(&dh->dh);
 }