Migrate all enumerators to venumerate() interface change

68 files changed, 851 insertions, 560 deletions

diff --git a/src/charon-nm/nm/nm_creds.c b/src/charon-nm/nm/nm_creds.c
index f8fae9504..c191ffde5 100644
--- a/src/charon-nm/nm/nm_creds.c
+++ b/src/charon-nm/nm/nm_creds.c
@@ -235,9 +235,13 @@ typedef struct {
 } shared_enumerator_t;
 
 METHOD(enumerator_t, shared_enumerate, bool,
-	shared_enumerator_t *this, shared_key_t **key, id_match_t *me,
-	id_match_t *other)
+	shared_enumerator_t *this, va_list args)
 {
+	shared_key_t **key;
+	id_match_t *me, *other;
+
+	VA_ARGS_VGET(args, key, me, other);
+
 	if (this->done)
 	{
 		return FALSE;
@@ -307,7 +311,8 @@ METHOD(credential_set_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_shared_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerate,
 			.destroy = _shared_destroy,
 		},
 		.this = this,
diff --git a/src/charon-nm/nm/nm_handler.c b/src/charon-nm/nm/nm_handler.c
index bdc0667cf..6c81afa0e 100644
--- a/src/charon-nm/nm/nm_handler.c
+++ b/src/charon-nm/nm/nm_handler.c
@@ -65,29 +65,33 @@ METHOD(attribute_handler_t, handle, bool,
 	return TRUE;
 }
 
-/**
- * Implementation of create_attribute_enumerator().enumerate() for WINS
- */
-static bool enumerate_nbns(enumerator_t *this,
-						   configuration_attribute_type_t *type, chunk_t *data)
+METHOD(enumerator_t, enumerate_nbns, bool,
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP4_NBNS;
 	*data = chunk_empty;
-	/* done */
-	this->enumerate = (void*)return_false;
+	this->venumerate = (void*)return_false;
 	return TRUE;
 }
 
 /**
  * Implementation of create_attribute_enumerator().enumerate() for DNS
  */
-static bool enumerate_dns(enumerator_t *this,
-						  configuration_attribute_type_t *type, chunk_t *data)
+METHOD(enumerator_t, enumerate_dns, bool,
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP4_DNS;
 	*data = chunk_empty;
 	/* enumerate WINS server as next attribute ... */
-	this->enumerate = (void*)enumerate_nbns;
+	this->venumerate = _enumerate_nbns;
 	return TRUE;
 }
 
@@ -100,7 +104,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t*,
 
 		INIT(enumerator,
 			/* enumerate DNS attribute first ... */
-			.enumerate = (void*)enumerate_dns,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_dns,
 			.destroy = (void*)free,
 		);
 		return enumerator;
diff --git a/src/dumm/dumm.c b/src/dumm/dumm.c
index cc4f5a16b..d147b2df0 100644
--- a/src/dumm/dumm.c
+++ b/src/dumm/dumm.c
@@ -267,10 +267,12 @@ typedef struct {
 } template_enumerator_t;
 
 METHOD(enumerator_t, template_enumerate, bool,
-	template_enumerator_t *this, char **template)
+	template_enumerator_t *this, va_list args)
 {
 	struct stat st;
-	char *rel;
+	char *rel, **template;
+
+	VA_ARGS_VGET(args, template);
 
 	while (this->inner->enumerate(this->inner, &rel, NULL, &st))
 	{
@@ -296,7 +298,8 @@ METHOD(dumm_t, create_template_enumerator, enumerator_t*,
 	template_enumerator_t *enumerator;
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_template_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _template_enumerate,
 			.destroy = (void*)_template_enumerator_destroy,
 		},
 		.inner = enumerator_create_directory(TEMPLATE_DIR),
diff --git a/src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_attr.c b/src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_attr.c
index 47933d1f2..5e4898fc3 100644
--- a/src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_attr.c
+++ b/src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_attr.c
@@ -73,20 +73,28 @@ METHOD(attribute_handler_t, release, void,
 }
 
 METHOD(enumerator_t, enumerate_dns6, bool,
-	enumerator_t *this, configuration_attribute_type_t *type, chunk_t *data)
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP6_DNS;
 	*data = chunk_empty;
-	this->enumerate = (void*)return_false;
+	this->venumerate = (void*)return_false;
 	return TRUE;
 }
 
 METHOD(enumerator_t, enumerate_dns4, bool,
-	enumerator_t *this, configuration_attribute_type_t *type, chunk_t *data)
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP4_DNS;
 	*data = chunk_empty;
-	this->enumerate = (void*)_enumerate_dns6;
+	this->venumerate = _enumerate_dns6;
 	return TRUE;
 }
 
@@ -96,7 +104,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t*,
 	enumerator_t *enumerator;
 
 	INIT(enumerator,
-			.enumerate = (void*)_enumerate_dns4,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_dns4,
 			.destroy = (void*)free,
 	);
 	return enumerator;
diff --git a/src/libcharon/attributes/attribute_manager.c b/src/libcharon/attributes/attribute_manager.c
index 2ab7ed118..3a4a21a02 100644
--- a/src/libcharon/attributes/attribute_manager.c
+++ b/src/libcharon/attributes/attribute_manager.c
@@ -237,14 +237,14 @@ typedef struct {
 	linked_list_t *vips;
 } initiator_enumerator_t;
 
-/**
- * Enumerator implementation for initiator attributes
- */
-static bool initiator_enumerate(initiator_enumerator_t *this,
-								attribute_handler_t **handler,
-								configuration_attribute_type_t *type,
-								chunk_t *value)
+METHOD(enumerator_t, initiator_enumerate, bool,
+	initiator_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	attribute_handler_t **handler;
+	chunk_t *value;
+
+	VA_ARGS_VGET(args, handler, type, value);
 	/* enumerate inner attributes using outer handler enumerator */
 	while (!this->inner || !this->inner->enumerate(this->inner, type, value))
 	{
@@ -261,10 +261,8 @@ static bool initiator_enumerate(initiator_enumerator_t *this,
 	return TRUE;
 }
 
-/**
- * Cleanup function of initiator attribute enumerator
- */
-static void initiator_destroy(initiator_enumerator_t *this)
+METHOD(enumerator_t, initiator_destroy, void,
+	initiator_enumerator_t *this)
 {
 	this->this->lock->unlock(this->this->lock);
 	this->outer->destroy(this->outer);
@@ -281,8 +279,9 @@ METHOD(attribute_manager_t, create_initiator_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)initiator_enumerate,
-			.destroy = (void*)initiator_destroy,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _initiator_enumerate,
+			.destroy = _initiator_destroy,
 		},
 		.this = this,
 		.ike_sa = ike_sa,
diff --git a/src/libcharon/attributes/mem_pool.c b/src/libcharon/attributes/mem_pool.c
index a2b7c2803..e1a9a6dce 100644
--- a/src/libcharon/attributes/mem_pool.c
+++ b/src/libcharon/attributes/mem_pool.c
@@ -512,10 +512,15 @@ typedef struct {
 } lease_enumerator_t;
 
 METHOD(enumerator_t, lease_enumerate, bool,
-	lease_enumerator_t *this, identification_t **id, host_t **addr, bool *online)
+	lease_enumerator_t *this, va_list args)
 {
-	u_int *offset;
+	identification_t **id;
 	unique_lease_t *lease;
+	host_t **addr;
+	u_int *offset;
+	bool *online;
+
+	VA_ARGS_VGET(args, id, addr, online);
 
 	DESTROY_IF(this->addr);
 	this->addr = NULL;
@@ -570,7 +575,8 @@ METHOD(mem_pool_t, create_lease_enumerator, enumerator_t*,
 	this->mutex->lock(this->mutex);
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_lease_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _lease_enumerate,
 			.destroy = _lease_enumerator_destroy,
 		},
 		.pool = this,
diff --git a/src/libcharon/config/peer_cfg.c b/src/libcharon/config/peer_cfg.c
index 5d7ab076e..fcdd6fdeb 100644
--- a/src/libcharon/config/peer_cfg.c
+++ b/src/libcharon/config/peer_cfg.c
@@ -209,9 +209,12 @@ typedef struct {
 } child_cfgs_replace_enumerator_t;
 
 METHOD(enumerator_t, child_cfgs_replace_enumerate, bool,
-	child_cfgs_replace_enumerator_t *this, child_cfg_t **chd, bool *added)
+	child_cfgs_replace_enumerator_t *this, va_list args)
 {
-	child_cfg_t *child_cfg;
+	child_cfg_t *child_cfg, **chd;
+	bool *added;
+
+	VA_ARGS_VGET(args, chd, added);
 
 	if (!this->wrapped)
 	{
@@ -303,8 +306,9 @@ METHOD(peer_cfg_t, replace_child_cfgs, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_child_cfgs_replace_enumerate,
-			.destroy = (void*)_child_cfgs_replace_enumerator_destroy,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _child_cfgs_replace_enumerate,
+			.destroy = _child_cfgs_replace_enumerator_destroy,
 		},
 		.removed = removed,
 		.added = added,
@@ -336,8 +340,11 @@ METHOD(enumerator_t, child_cfg_enumerator_destroy, void,
 }
 
 METHOD(enumerator_t, child_cfg_enumerate, bool,
-	child_cfg_enumerator_t *this, child_cfg_t **chd)
+	child_cfg_enumerator_t *this, va_list args)
 {
+	child_cfg_t **chd;
+
+	VA_ARGS_VGET(args, chd);
 	return this->wrapped->enumerate(this->wrapped, chd);
 }
 
@@ -348,8 +355,9 @@ METHOD(peer_cfg_t, create_child_cfg_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_child_cfg_enumerate,
-			.destroy = (void*)_child_cfg_enumerator_destroy,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _child_cfg_enumerate,
+			.destroy = _child_cfg_enumerator_destroy,
 		},
 		.mutex = this->mutex,
 		.wrapped = this->child_cfgs->create_enumerator(this->child_cfgs),
diff --git a/src/libcharon/encoding/payloads/certreq_payload.c b/src/libcharon/encoding/payloads/certreq_payload.c
index 09bfa2458..643fbc42f 100644
--- a/src/libcharon/encoding/payloads/certreq_payload.c
+++ b/src/libcharon/encoding/payloads/certreq_payload.c
@@ -190,8 +190,12 @@ struct keyid_enumerator_t  {
 };
 
 METHOD(enumerator_t, keyid_enumerate, bool,
-	keyid_enumerator_t *this, chunk_t *chunk)
+	keyid_enumerator_t *this, va_list args)
 {
+	chunk_t *chunk;
+
+	VA_ARGS_VGET(args, chunk);
+
 	if (this->pos == NULL)
 	{
 		this->pos = this->full.ptr;
@@ -224,7 +228,8 @@ METHOD(certreq_payload_t, create_keyid_enumerator, enumerator_t*,
 	}
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_keyid_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _keyid_enumerate,
 			.destroy = (void*)free,
 		},
 		.full = this->data,
diff --git a/src/libcharon/encoding/payloads/delete_payload.c b/src/libcharon/encoding/payloads/delete_payload.c
index 584e6f22b..3634cd36c 100644
--- a/src/libcharon/encoding/payloads/delete_payload.c
+++ b/src/libcharon/encoding/payloads/delete_payload.c
@@ -306,8 +306,12 @@ typedef struct {
 } spi_enumerator_t;
 
 METHOD(enumerator_t, spis_enumerate, bool,
-	spi_enumerator_t *this, uint32_t *spi)
+	spi_enumerator_t *this, va_list args)
 {
+	uint32_t *spi;
+
+	VA_ARGS_VGET(args, spi);
+
 	if (this->spis.len >= sizeof(*spi))
 	{
 		memcpy(spi, this->spis.ptr, sizeof(*spi));
@@ -328,7 +332,8 @@ METHOD(delete_payload_t, create_spi_enumerator, enumerator_t*,
 	}
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_spis_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _spis_enumerate,
 			.destroy = (void*)free,
 		},
 		.spis = this->spis,
diff --git a/src/libcharon/encoding/payloads/eap_payload.c b/src/libcharon/encoding/payloads/eap_payload.c
index 8c3fc5933..923135da9 100644
--- a/src/libcharon/encoding/payloads/eap_payload.c
+++ b/src/libcharon/encoding/payloads/eap_payload.c
@@ -270,8 +270,12 @@ typedef struct {
 } type_enumerator_t;
 
 METHOD(enumerator_t, enumerate_types, bool,
-	type_enumerator_t *this, eap_type_t *type, uint32_t *vendor)
+	type_enumerator_t *this, va_list args)
 {
+	eap_type_t *type;
+	uint32_t *vendor;
+
+	VA_ARGS_VGET(args, type, vendor);
 	this->offset = extract_type(this->payload, this->offset, type, vendor);
 	return this->offset;
 }
@@ -289,7 +293,8 @@ METHOD(eap_payload_t, get_types, enumerator_t*,
 	{
 		INIT(enumerator,
 			.public = {
-				.enumerate = (void*)_enumerate_types,
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _enumerate_types,
 				.destroy = (void*)free,
 			},
 			.payload = this,
diff --git a/src/libcharon/plugins/android_dns/android_dns_handler.c b/src/libcharon/plugins/android_dns/android_dns_handler.c
index 160a145d3..68bbaecb2 100644
--- a/src/libcharon/plugins/android_dns/android_dns_handler.c
+++ b/src/libcharon/plugins/android_dns/android_dns_handler.c
@@ -182,12 +182,15 @@ METHOD(attribute_handler_t, release, void,
 }
 
 METHOD(enumerator_t, enumerate_dns, bool,
-	enumerator_t *this, configuration_attribute_type_t *type, chunk_t *data)
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP4_DNS;
 	*data = chunk_empty;
-	/* stop enumeration */
-	this->enumerate = (void*)return_false;
+	this->venumerate = return_false;
 	return TRUE;
 }
 
@@ -198,7 +201,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t *,
 	enumerator_t *enumerator;
 
 	INIT(enumerator,
-		.enumerate = (void*)_enumerate_dns,
+		.enumerate = enumerator_enumerate_default,
+		.venumerate = _enumerate_dns,
 		.destroy = (void*)free,
 	);
 	return enumerator;
diff --git a/src/libcharon/plugins/dnscert/dnscert_cred.c b/src/libcharon/plugins/dnscert/dnscert_cred.c
index d32794c99..533bd5be4 100644
--- a/src/libcharon/plugins/dnscert/dnscert_cred.c
+++ b/src/libcharon/plugins/dnscert/dnscert_cred.c
@@ -75,12 +75,15 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **cert)
+	cert_enumerator_t *this, va_list args)
 {
+	certificate_t **cert;
 	dnscert_t *cur_crt;
 	rr_t *cur_rr;
 	chunk_t certificate;
 
+	VA_ARGS_VGET(args, cert);
+
 	/* Get the next supported CERT using the inner enumerator. */
 	while (this->inner->enumerate(this->inner, &cur_rr))
 	{
@@ -175,7 +178,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 		.inner = response->get_rr_set(response)->create_rr_enumerator(
diff --git a/src/libcharon/plugins/eap_radius/eap_radius_provider.c b/src/libcharon/plugins/eap_radius/eap_radius_provider.c
index 9a87ad38d..58bbc2edd 100644
--- a/src/libcharon/plugins/eap_radius/eap_radius_provider.c
+++ b/src/libcharon/plugins/eap_radius/eap_radius_provider.c
@@ -404,11 +404,13 @@ typedef struct {
 	attr_t *current;
 } attribute_enumerator_t;
 
-
 METHOD(enumerator_t, attribute_enumerate, bool,
-	attribute_enumerator_t *this, configuration_attribute_type_t *type,
-	chunk_t *data)
+	attribute_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	if (this->current)
 	{
 		destroy_attr(this->current);
@@ -446,7 +448,8 @@ METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_attribute_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _attribute_enumerate,
 			.destroy = _attribute_destroy,
 		},
 		.list = linked_list_create(),
diff --git a/src/libcharon/plugins/eap_sim_file/eap_sim_file_triplets.c b/src/libcharon/plugins/eap_sim_file/eap_sim_file_triplets.c
index ec1686910..e11e0e5ea 100644
--- a/src/libcharon/plugins/eap_sim_file/eap_sim_file_triplets.c
+++ b/src/libcharon/plugins/eap_sim_file/eap_sim_file_triplets.c
@@ -79,10 +79,8 @@ typedef struct {
 	private_eap_sim_file_triplets_t *this;
 } triplet_enumerator_t;
 
-/**
- * destroy a triplet enumerator
- */
-static void enumerator_destroy(triplet_enumerator_t *e)
+METHOD(enumerator_t, enumerator_destroy, void,
+	triplet_enumerator_t *e)
 {
 	if (e->current)
 	{
@@ -97,13 +95,14 @@ static void enumerator_destroy(triplet_enumerator_t *e)
 	free(e);
 }
 
-/**
- * enumerate through triplets
- */
-static bool enumerator_enumerate(triplet_enumerator_t *e, identification_t **imsi,
-								 char **rand, char **sres, char **kc)
+METHOD(enumerator_t, enumerator_enumerate, bool,
+	triplet_enumerator_t *e, va_list args)
 {
+	identification_t **imsi;
 	triplet_t *triplet;
+	char **rand, **sres, **kc;
+
+	VA_ARGS_VGET(args, imsi, rand, sres, kc);
 
 	if (e->inner->enumerate(e->inner, &triplet))
 	{
@@ -124,12 +123,15 @@ METHOD(eap_sim_file_triplets_t, create_enumerator, enumerator_t*,
 	triplet_enumerator_t *enumerator = malloc_thing(triplet_enumerator_t);
 
 	this->mutex->lock(this->mutex);
-	enumerator->public.enumerate = (void*)enumerator_enumerate;
-	enumerator->public.destroy = (void*)enumerator_destroy;
-	enumerator->inner = this->triplets->create_enumerator(this->triplets);
-	enumerator->current = NULL;
-	enumerator->this = this;
-
+	INIT(enumerator,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerator_enumerate,
+			.destroy = _enumerator_destroy,
+		},
+		.inner = this->triplets->create_enumerator(this->triplets),
+		.this = this,
+	);
 	return &enumerator->public;
 }
 
diff --git a/src/libcharon/plugins/ha/ha_message.c b/src/libcharon/plugins/ha/ha_message.c
index 42dfaf0e2..5f73b7156 100644
--- a/src/libcharon/plugins/ha/ha_message.c
+++ b/src/libcharon/plugins/ha/ha_message.c
@@ -331,10 +331,12 @@ typedef struct {
 } attribute_enumerator_t;
 
 METHOD(enumerator_t, attribute_enumerate, bool,
-	attribute_enumerator_t *this, ha_message_attribute_t *attr_out,
-	ha_message_value_t *value)
+	attribute_enumerator_t *this, va_list args)
 {
-	ha_message_attribute_t attr;
+	ha_message_attribute_t attr, *attr_out;
+	ha_message_value_t *value;
+
+	VA_ARGS_VGET(args, attr_out, value);
 
 	if (this->cleanup)
 	{
@@ -602,7 +604,8 @@ METHOD(ha_message_t, create_attribute_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_attribute_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _attribute_enumerate,
 			.destroy = _enum_destroy,
 		},
 		.buf = chunk_skip(this->buf, 2),
diff --git a/src/libcharon/plugins/ha/ha_tunnel.c b/src/libcharon/plugins/ha/ha_tunnel.c
index a0e514614..1a6108ed9 100644
--- a/src/libcharon/plugins/ha/ha_tunnel.c
+++ b/src/libcharon/plugins/ha/ha_tunnel.c
@@ -111,8 +111,12 @@ typedef struct {
 } shared_enum_t;
 
 METHOD(enumerator_t, shared_enumerate, bool,
-	shared_enum_t *this, shared_key_t **key, id_match_t *me, id_match_t *other)
+	shared_enum_t *this, va_list args)
 {
+	shared_key_t **key;
+	id_match_t *me, *other;
+
+	VA_ARGS_VGET(args, key, me, other);
 	if (this->key)
 	{
 		if (me)
@@ -151,7 +155,8 @@ METHOD(ha_creds_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_shared_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerate,
 			.destroy = (void*)free,
 		},
 		.key = this->key,
diff --git a/src/libcharon/plugins/ipseckey/ipseckey_cred.c b/src/libcharon/plugins/ipseckey/ipseckey_cred.c
index ff50d8a17..b3ac2b328 100644
--- a/src/libcharon/plugins/ipseckey/ipseckey_cred.c
+++ b/src/libcharon/plugins/ipseckey/ipseckey_cred.c
@@ -62,13 +62,16 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **cert)
+	cert_enumerator_t *this, va_list args)
 {
+	certificate_t **cert;
 	ipseckey_t *cur_ipseckey;
 	public_key_t *public;
 	rr_t *cur_rr;
 	chunk_t key;
 
+	VA_ARGS_VGET(args, cert);
+
 	/* Get the next supported IPSECKEY using the inner enumerator. */
 	while (this->inner->enumerate(this->inner, &cur_rr))
 	{
@@ -211,7 +214,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 		.inner = rrset->create_rr_enumerator(rrset),
diff --git a/src/libcharon/plugins/kernel_iph/kernel_iph_net.c b/src/libcharon/plugins/kernel_iph/kernel_iph_net.c
index efeb98045..18a87b707 100644
--- a/src/libcharon/plugins/kernel_iph/kernel_iph_net.c
+++ b/src/libcharon/plugins/kernel_iph/kernel_iph_net.c
@@ -466,9 +466,12 @@ typedef struct {
 } addr_enumerator_t;
 
 METHOD(enumerator_t, addr_enumerate, bool,
-	addr_enumerator_t *this, host_t **host)
+	addr_enumerator_t *this, va_list args)
 {
 	iface_t *entry;
+	host_t **host;
+
+	VA_ARGS_VGET(args, host);
 
 	while (TRUE)
 	{
@@ -523,7 +526,8 @@ METHOD(kernel_net_t, create_address_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_addr_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _addr_enumerate,
 			.destroy = _addr_destroy,
 		},
 		.which = which,
diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
index 2dc76d941..f94992d5d 100644
--- a/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
+++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_net.c
@@ -2165,8 +2165,14 @@ METHOD(enumerator_t, destroy_subnet_enumerator, void,
 }
 
 METHOD(enumerator_t, enumerate_subnets, bool,
-	subnet_enumerator_t *this, host_t **net, uint8_t *mask, char **ifname)
+	subnet_enumerator_t *this, va_list args)
 {
+	host_t **net;
+	uint8_t *mask;
+	char **ifname;
+
+	VA_ARGS_VGET(args, net, mask, ifname);
+
 	if (!this->current)
 	{
 		this->current = this->msg;
@@ -2270,7 +2276,8 @@ METHOD(kernel_net_t, create_local_subnet_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_subnets,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_subnets,
 			.destroy = _destroy_subnet_enumerator,
 		},
 		.private = this,
diff --git a/src/libcharon/plugins/kernel_pfroute/kernel_pfroute_net.c b/src/libcharon/plugins/kernel_pfroute/kernel_pfroute_net.c
index efcf1c2a7..7b370666c 100644
--- a/src/libcharon/plugins/kernel_pfroute/kernel_pfroute_net.c
+++ b/src/libcharon/plugins/kernel_pfroute/kernel_pfroute_net.c
@@ -601,9 +601,12 @@ typedef struct {
 } rt_enumerator_t;
 
 METHOD(enumerator_t, rt_enumerate, bool,
-	rt_enumerator_t *this, int *xtype, struct sockaddr **addr)
+	rt_enumerator_t *this, va_list args)
 {
-	int i, type;
+	struct sockaddr **addr;
+	int i, type, *xtype;
+
+	VA_ARGS_VGET(args, xtype, addr);
 
 	if (this->remaining < sizeof(this->addr->sa_len) ||
 		this->remaining < this->addr->sa_len)
@@ -637,7 +640,8 @@ static enumerator_t *create_rt_enumerator(int types, int remaining,
 
 	INIT(this,
 		.public = {
-			.enumerate = (void*)_rt_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _rt_enumerate,
 			.destroy = (void*)free,
 		},
 		.types = types,
@@ -1789,13 +1793,18 @@ METHOD(enumerator_t, destroy_subnet_enumerator, void,
 }
 
 METHOD(enumerator_t, enumerate_subnets, bool,
-	subnet_enumerator_t *this, host_t **net, uint8_t *mask, char **ifname)
+	subnet_enumerator_t *this, va_list args)
 {
 	enumerator_t *enumerator;
+	host_t **net;
 	struct rt_msghdr *rtm;
 	struct sockaddr *addr;
+	uint8_t *mask;
+	char **ifname;
 	int type;
 
+	VA_ARGS_VGET(args, net, mask, ifname);
+
 	if (!this->current)
 	{
 		this->current = this->buf;
@@ -1888,7 +1897,8 @@ METHOD(kernel_net_t, create_local_subnet_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_subnets,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_subnets,
 			.destroy = _destroy_subnet_enumerator,
 		},
 		.buf = buf,
diff --git a/src/libcharon/plugins/medcli/medcli_config.c b/src/libcharon/plugins/medcli/medcli_config.c
index 78159c845..f34990176 100644
--- a/src/libcharon/plugins/medcli/medcli_config.c
+++ b/src/libcharon/plugins/medcli/medcli_config.c
@@ -223,10 +223,11 @@ typedef struct {
 } peer_enumerator_t;
 
 METHOD(enumerator_t, peer_enumerator_enumerate, bool,
-	peer_enumerator_t *this, peer_cfg_t **cfg)
+	peer_enumerator_t *this, va_list args)
 {
 	char *name, *local_net, *remote_net;
 	chunk_t me, other;
+	peer_cfg_t **cfg;
 	child_cfg_t *child_cfg;
 	auth_cfg_t *auth;
 	peer_cfg_create_t peer = {
@@ -249,6 +250,8 @@ METHOD(enumerator_t, peer_enumerator_enumerate, bool,
 		.mode = MODE_TUNNEL,
 	};
 
+	VA_ARGS_VGET(args, cfg);
+
 	DESTROY_IF(this->current);
 	if (!this->inner->enumerate(this->inner, &name, &me, &other,
 								&local_net, &remote_net))
@@ -295,7 +298,8 @@ METHOD(backend_t, create_peer_cfg_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_peer_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _peer_enumerator_enumerate,
 			.destroy = _peer_enumerator_destroy,
 		},
 		.ike = this->ike,
diff --git a/src/libcharon/plugins/medcli/medcli_creds.c b/src/libcharon/plugins/medcli/medcli_creds.c
index 677229b9f..528fc004d 100644
--- a/src/libcharon/plugins/medcli/medcli_creds.c
+++ b/src/libcharon/plugins/medcli/medcli_creds.c
@@ -50,10 +50,13 @@ typedef struct {
 } private_enumerator_t;
 
 METHOD(enumerator_t, private_enumerator_enumerate, bool,
-	private_enumerator_t *this, private_key_t **key)
+	private_enumerator_t *this, va_list args)
 {
+	private_key_t **key;
 	chunk_t chunk;
 
+	VA_ARGS_VGET(args, key);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &chunk))
 	{
@@ -92,7 +95,8 @@ METHOD(credential_set_t, create_private_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_private_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _private_enumerator_enumerate,
 			.destroy = _private_enumerator_destroy,
 		},
 	);
@@ -123,11 +127,14 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **cert)
+	cert_enumerator_t *this, va_list args)
 {
+	certificate_t **cert;
 	public_key_t *public;
 	chunk_t chunk;
 
+	VA_ARGS_VGET(args, cert);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &chunk))
 	{
@@ -180,7 +187,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 		.type = key,
diff --git a/src/libcharon/plugins/medsrv/medsrv_creds.c b/src/libcharon/plugins/medsrv/medsrv_creds.c
index 0d99c4f77..16d4bd7f3 100644
--- a/src/libcharon/plugins/medsrv/medsrv_creds.c
+++ b/src/libcharon/plugins/medsrv/medsrv_creds.c
@@ -52,12 +52,14 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **cert)
+	cert_enumerator_t *this, va_list args)
 {
-	certificate_t *trusted;
+	certificate_t *trusted, **cert;
 	public_key_t *public;
 	chunk_t chunk;
 
+	VA_ARGS_VGET(args, cert);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &chunk))
 	{
@@ -110,7 +112,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 		.type = key,
diff --git a/src/libcharon/plugins/osx_attr/osx_attr_handler.c b/src/libcharon/plugins/osx_attr/osx_attr_handler.c
index 6baf76d35..e7a627b93 100644
--- a/src/libcharon/plugins/osx_attr/osx_attr_handler.c
+++ b/src/libcharon/plugins/osx_attr/osx_attr_handler.c
@@ -218,12 +218,15 @@ METHOD(attribute_handler_t, release, void,
 }
 
 METHOD(enumerator_t, enumerate_dns, bool,
-	enumerator_t *this, configuration_attribute_type_t *type, chunk_t *data)
+	enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	*type = INTERNAL_IP4_DNS;
 	*data = chunk_empty;
-	/* stop enumeration */
-	this->enumerate = (void*)return_false;
+	this->venumerate = (void*)return_false;
 	return TRUE;
 }
 
@@ -234,7 +237,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t *,
 	enumerator_t *enumerator;
 
 	INIT(enumerator,
-		.enumerate = (void*)_enumerate_dns,
+		.enumerate = enumerator_enumerate_default,
+		.venumerate = _enumerate_dns,
 		.destroy = (void*)free,
 	);
 	return enumerator;
diff --git a/src/libcharon/plugins/p_cscf/p_cscf_handler.c b/src/libcharon/plugins/p_cscf/p_cscf_handler.c
index 76633845e..880e80a56 100644
--- a/src/libcharon/plugins/p_cscf/p_cscf_handler.c
+++ b/src/libcharon/plugins/p_cscf/p_cscf_handler.c
@@ -83,9 +83,12 @@ typedef struct {
 } attr_enumerator_t;
 
 METHOD(enumerator_t, enumerate_attrs, bool,
-	attr_enumerator_t *this, configuration_attribute_type_t *type,
-	chunk_t *data)
+	attr_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	if (this->request_ipv4)
 	{
 		*type = P_CSCF_IP4_ADDRESS;
@@ -132,7 +135,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t *,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_attrs,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_attrs,
 			.destroy = (void*)free,
 		},
 	);
diff --git a/src/libcharon/plugins/resolve/resolve_handler.c b/src/libcharon/plugins/resolve/resolve_handler.c
index 9077b51d4..05b865464 100644
--- a/src/libcharon/plugins/resolve/resolve_handler.c
+++ b/src/libcharon/plugins/resolve/resolve_handler.c
@@ -391,10 +391,13 @@ typedef struct {
 	bool v6;
 } attribute_enumerator_t;
 
-static bool attribute_enumerate(attribute_enumerator_t *this,
-								configuration_attribute_type_t *type,
-								chunk_t *data)
+METHOD(enumerator_t, attribute_enumerate, bool,
+	attribute_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	if (this->v4)
 	{
 		*type = INTERNAL_IP4_DNS;
@@ -443,7 +446,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)attribute_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _attribute_enumerate,
 			.destroy = (void*)free,
 		},
 		.v4 = has_host_family(vips, AF_INET),
diff --git a/src/libcharon/plugins/sql/sql_config.c b/src/libcharon/plugins/sql/sql_config.c
index cf7c3b814..55e818122 100644
--- a/src/libcharon/plugins/sql/sql_config.c
+++ b/src/libcharon/plugins/sql/sql_config.c
@@ -504,11 +504,12 @@ typedef struct {
 	ike_cfg_t *current;
 } ike_enumerator_t;
 
-/**
- * Implementation of ike_enumerator_t.public.enumerate
- */
-static bool ike_enumerator_enumerate(ike_enumerator_t *this, ike_cfg_t **cfg)
+METHOD(enumerator_t, ike_enumerator_enumerate, bool,
+	ike_enumerator_t *this, va_list args)
 {
+	ike_cfg_t **cfg;
+
+	VA_ARGS_VGET(args, cfg);
 	DESTROY_IF(this->current);
 	this->current = build_ike_cfg(this->this, this->inner, this->me, this->other);
 	if (this->current)
@@ -519,10 +520,8 @@ static bool ike_enumerator_enumerate(ike_enumerator_t *this, ike_cfg_t **cfg)
 	return FALSE;
 }
 
-/**
- * Implementation of ike_enumerator_t.public.destroy
- */
-static void ike_enumerator_destroy(ike_enumerator_t *this)
+METHOD(enumerator_t, ike_enumerator_destroy, void,
+	ike_enumerator_t *this)
 {
 	DESTROY_IF(this->current);
 	this->inner->destroy(this->inner);
@@ -532,19 +531,22 @@ static void ike_enumerator_destroy(ike_enumerator_t *this)
 METHOD(backend_t, create_ike_cfg_enumerator, enumerator_t*,
 	private_sql_config_t *this, host_t *me, host_t *other)
 {
-	ike_enumerator_t *e = malloc_thing(ike_enumerator_t);
-
-	e->this = this;
-	e->me = me;
-	e->other = other;
-	e->current = NULL;
-	e->public.enumerate = (void*)ike_enumerator_enumerate;
-	e->public.destroy = (void*)ike_enumerator_destroy;
+	ike_enumerator_t *e;
 
+	INIT(e,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _ike_enumerator_enumerate,
+			.destroy = _ike_enumerator_destroy,
+		},
+		.this = this,
+		.me = me,
+		.other = other,
+	);
 	e->inner = this->db->query(this->db,
-			"SELECT id, certreq, force_encap, local, remote "
-			"FROM ike_configs",
-			DB_INT, DB_INT, DB_INT, DB_TEXT, DB_TEXT);
+							   "SELECT id, certreq, force_encap, local, remote "
+							   "FROM ike_configs",
+							   DB_INT, DB_INT, DB_INT, DB_TEXT, DB_TEXT);
 	if (!e->inner)
 	{
 		free(e);
@@ -569,11 +571,12 @@ typedef struct {
 	peer_cfg_t *current;
 } peer_enumerator_t;
 
-/**
- * Implementation of peer_enumerator_t.public.enumerate
- */
-static bool peer_enumerator_enumerate(peer_enumerator_t *this, peer_cfg_t **cfg)
+METHOD(enumerator_t, peer_enumerator_enumerate, bool,
+	peer_enumerator_t *this, va_list args)
 {
+	peer_cfg_t **cfg;
+
+	VA_ARGS_VGET(args, cfg);
 	DESTROY_IF(this->current);
 	this->current = build_peer_cfg(this->this, this->inner, this->me, this->other);
 	if (this->current)
@@ -584,10 +587,8 @@ static bool peer_enumerator_enumerate(peer_enumerator_t *this, peer_cfg_t **cfg)
 	return FALSE;
 }
 
-/**
- * Implementation of peer_enumerator_t.public.destroy
- */
-static void peer_enumerator_destroy(peer_enumerator_t *this)
+METHOD(enumerator_t, peer_enumerator_destroy, void,
+	peer_enumerator_t *this)
 {
 	DESTROY_IF(this->current);
 	this->inner->destroy(this->inner);
@@ -599,12 +600,16 @@ METHOD(backend_t, create_peer_cfg_enumerator, enumerator_t*,
 {
 	peer_enumerator_t *e = malloc_thing(peer_enumerator_t);
 
-	e->this = this;
-	e->me = me;
-	e->other = other;
-	e->current = NULL;
-	e->public.enumerate = (void*)peer_enumerator_enumerate;
-	e->public.destroy = (void*)peer_enumerator_destroy;
+	INIT(e,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _peer_enumerator_enumerate,
+			.destroy = _peer_enumerator_destroy,
+		},
+		.this = this,
+		.me = me,
+		.other = other,
+	);
 
 	/* TODO: only get configs whose IDs match exactly or contain wildcards */
 	e->inner = this->db->query(this->db,
diff --git a/src/libcharon/plugins/sql/sql_cred.c b/src/libcharon/plugins/sql/sql_cred.c
index 117eec921..3317de6c8 100644
--- a/src/libcharon/plugins/sql/sql_cred.c
+++ b/src/libcharon/plugins/sql/sql_cred.c
@@ -52,11 +52,14 @@ typedef struct {
 } private_enumerator_t;
 
 METHOD(enumerator_t, private_enumerator_enumerate, bool,
-	   private_enumerator_t *this, private_key_t **key)
+	   private_enumerator_t *this, va_list args)
 {
+	private_key_t **key;
 	chunk_t blob;
 	int type;
 
+	VA_ARGS_VGET(args, key);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -88,7 +91,8 @@ METHOD(credential_set_t, create_private_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_private_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _private_enumerator_enumerate,
 			.destroy = _private_enumerator_destroy,
 		},
 	);
@@ -132,11 +136,14 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	   cert_enumerator_t *this, certificate_t **cert)
+	   cert_enumerator_t *this, va_list args)
 {
+	certificate_t **cert;
 	chunk_t blob;
 	int type;
 
+	VA_ARGS_VGET(args, cert);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -169,7 +176,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 	);
@@ -221,12 +229,15 @@ typedef struct {
 } shared_enumerator_t;
 
 METHOD(enumerator_t, shared_enumerator_enumerate, bool,
-	   shared_enumerator_t *this, shared_key_t **shared,
-	   id_match_t *me, id_match_t *other)
+	   shared_enumerator_t *this, va_list args)
 {
+	shared_key_t **shared;
+	id_match_t *me, *other;
 	chunk_t blob;
 	int type;
 
+	VA_ARGS_VGET(args, shared, me, other);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -265,7 +276,8 @@ METHOD(credential_set_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_shared_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerator_enumerate,
 			.destroy = _shared_enumerator_destroy,
 		},
 		.me = me,
@@ -340,9 +352,11 @@ typedef enum {
 } cdp_type_t;
 
 METHOD(enumerator_t, cdp_enumerator_enumerate, bool,
-	   cdp_enumerator_t *this, char **uri)
+	   cdp_enumerator_t *this, va_list args)
 {
-	char *text;
+	char *text, **uri;
+
+	VA_ARGS_VGET(args, uri);
 
 	free(this->current);
 	while (this->inner->enumerate(this->inner, &text))
@@ -384,7 +398,8 @@ METHOD(credential_set_t, create_cdp_enumerator, enumerator_t*,
 	}
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cdp_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cdp_enumerator_enumerate,
 			.destroy = _cdp_enumerator_destroy,
 		},
 	);
diff --git a/src/libcharon/plugins/uci/uci_config.c b/src/libcharon/plugins/uci/uci_config.c
index e0578fe9b..dcd4ae348 100644
--- a/src/libcharon/plugins/uci/uci_config.c
+++ b/src/libcharon/plugins/uci/uci_config.c
@@ -118,11 +118,12 @@ static u_int create_rekey(char *string)
 }
 
 METHOD(enumerator_t, peer_enumerator_enumerate, bool,
-	peer_enumerator_t *this, peer_cfg_t **cfg)
+	peer_enumerator_t *this, va_list args)
 {
 	char *name, *ike_proposal, *esp_proposal, *ike_rekey, *esp_rekey;
 	char *local_id, *local_addr, *local_net;
 	char *remote_id, *remote_addr, *remote_net;
+	peer_cfg_t **cfg;
 	child_cfg_t *child_cfg;
 	ike_cfg_t *ike_cfg;
 	auth_cfg_t *auth;
@@ -145,6 +146,8 @@ METHOD(enumerator_t, peer_enumerator_enumerate, bool,
 		.mode = MODE_TUNNEL,
 	};
 
+	VA_ARGS_VGET(args, cfg);
+
 	/* defaults */
 	name = "unnamed";
 	local_id = NULL;
@@ -212,7 +215,8 @@ METHOD(backend_t, create_peer_cfg_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_peer_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _peer_enumerator_enumerate,
 			.destroy = _peer_enumerator_destroy,
 		},
 		.inner = this->parser->create_section_enumerator(this->parser,
@@ -241,10 +245,13 @@ typedef struct {
 } ike_enumerator_t;
 
 METHOD(enumerator_t, ike_enumerator_enumerate, bool,
-	ike_enumerator_t *this, ike_cfg_t **cfg)
+	ike_enumerator_t *this, va_list args)
 {
+	ike_cfg_t **cfg;
 	char *local_addr, *remote_addr, *ike_proposal;
 
+	VA_ARGS_VGET(args, cfg);
+
 	/* defaults */
 	local_addr = "0.0.0.0";
 	remote_addr = "0.0.0.0";
@@ -282,7 +289,8 @@ METHOD(backend_t, create_ike_cfg_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_ike_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _ike_enumerator_enumerate,
 			.destroy = _ike_enumerator_destroy,
 		},
 		.inner = this->parser->create_section_enumerator(this->parser,
diff --git a/src/libcharon/plugins/uci/uci_creds.c b/src/libcharon/plugins/uci/uci_creds.c
index f5d5ace70..404a3e39f 100644
--- a/src/libcharon/plugins/uci/uci_creds.c
+++ b/src/libcharon/plugins/uci/uci_creds.c
@@ -52,12 +52,15 @@ typedef struct {
 } shared_enumerator_t;
 
 METHOD(enumerator_t, shared_enumerator_enumerate, bool,
-	shared_enumerator_t *this, shared_key_t **key, id_match_t *me,
-	id_match_t *other)
+	shared_enumerator_t *this, va_list args)
 {
+	shared_key_t **key;
+	id_match_t *me, *other;
 	char *local_id, *remote_id, *psk;
 	identification_t *local, *remote;
 
+	VA_ARGS_VGET(args, key, me, other);
+
 	while (TRUE)
 	{
 		/* defaults */
@@ -126,7 +129,8 @@ METHOD(credential_set_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_shared_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerator_enumerate,
 			.destroy = _shared_enumerator_destroy,
 		},
 		.me = me,
diff --git a/src/libcharon/plugins/uci/uci_parser.c b/src/libcharon/plugins/uci/uci_parser.c
index 2429e9e44..e847dd393 100644
--- a/src/libcharon/plugins/uci/uci_parser.c
+++ b/src/libcharon/plugins/uci/uci_parser.c
@@ -58,11 +58,10 @@ typedef struct {
 } section_enumerator_t;
 
 METHOD(enumerator_t, section_enumerator_enumerate, bool,
-	section_enumerator_t *this, ...)
+	section_enumerator_t *this, va_list args)
 {
 	struct uci_element *element;
 	char **value;
-	va_list args;
 	int i;
 
 	if (&this->current->list == this->list)
@@ -70,8 +69,6 @@ METHOD(enumerator_t, section_enumerator_enumerate, bool,
 		return FALSE;
 	}
 
-	va_start(args, this);
-
 	value = va_arg(args, char**);
 	if (value)
 	{
@@ -96,7 +93,6 @@ METHOD(enumerator_t, section_enumerator_enumerate, bool,
 			*value = uci_to_option(element)->value;
 		}
 	}
-	va_end(args);
 
 	this->current = list_to_element(this->current->list.next);
 	return TRUE;
@@ -124,7 +120,13 @@ METHOD(uci_parser_t, create_section_enumerator, enumerator_t*,
 		i++;
 	}
 	va_end(args);
-	e = malloc(sizeof(section_enumerator_t) + sizeof(char*) * i);
+	INIT_EXTRA(e, sizeof(char*) * i,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _section_enumerator_enumerate,
+			.destroy = _section_enumerator_destroy,
+		},
+	);
 	i = 0;
 	va_start(args, this);
 	do
@@ -134,9 +136,6 @@ METHOD(uci_parser_t, create_section_enumerator, enumerator_t*,
 	while (e->keywords[i++]);
 	va_end(args);
 
-	e->public.enumerate = (void*)_section_enumerator_enumerate;
-	e->public.destroy = _section_enumerator_destroy;
-
 	/* load uci context */
 	e->ctx = uci_alloc_context();
 	if (uci_load(e->ctx, this->package, &e->package) != UCI_OK)
diff --git a/src/libcharon/plugins/unity/unity_handler.c b/src/libcharon/plugins/unity/unity_handler.c
index 25e0756b7..f640f9fbb 100644
--- a/src/libcharon/plugins/unity/unity_handler.c
+++ b/src/libcharon/plugins/unity/unity_handler.c
@@ -368,9 +368,12 @@ typedef struct {
 } attribute_enumerator_t;
 
 METHOD(enumerator_t, enumerate_attributes, bool,
-	attribute_enumerator_t *this, configuration_attribute_type_t *type,
-	chunk_t *data)
+	attribute_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
 	if (this->i < countof(attributes))
 	{
 		*type = attributes[this->i++];
@@ -393,7 +396,8 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t *,
 	}
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_attributes,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_attributes,
 			.destroy = (void*)free,
 		},
 	);
diff --git a/src/libcharon/plugins/unity/unity_provider.c b/src/libcharon/plugins/unity/unity_provider.c
index 07f5f9b61..b6a55648e 100644
--- a/src/libcharon/plugins/unity/unity_provider.c
+++ b/src/libcharon/plugins/unity/unity_provider.c
@@ -77,12 +77,15 @@ static void append_ts(bio_writer_t *writer, traffic_selector_t *ts)
 }
 
 METHOD(enumerator_t, attribute_enumerate, bool,
-	attribute_enumerator_t *this, configuration_attribute_type_t *type,
-	chunk_t *attr)
+	attribute_enumerator_t *this, va_list args)
 {
+	configuration_attribute_type_t *type;
+	chunk_t *attr;
 	traffic_selector_t *ts;
 	bio_writer_t *writer;
 
+	VA_ARGS_VGET(args, type, attr);
+
 	if (this->list->get_count(this->list) == 0)
 	{
 		return FALSE;
@@ -183,7 +186,8 @@ METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 
 	INIT(attr_enum,
 		.public = {
-			.enumerate = (void*)_attribute_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _attribute_enumerate,
 			.destroy = _attribute_destroy,
 		},
 		.list = list,
diff --git a/src/libcharon/plugins/vici/suites/test_message.c b/src/libcharon/plugins/vici/suites/test_message.c
index 045e34fff..73bba239b 100644
--- a/src/libcharon/plugins/vici/suites/test_message.c
+++ b/src/libcharon/plugins/vici/suites/test_message.c
@@ -122,9 +122,14 @@ typedef struct {
 	endecode_test_t *next;
 } endecode_enum_t;
 
-static bool endecode_enumerate(endecode_enum_t *this, vici_type_t *type,
-							   char **name, chunk_t *data)
+METHOD(enumerator_t, endecode_enumerate, bool,
+	endecode_enum_t *this, va_list args)
 {
+	vici_type_t *type;
+	chunk_t *data;
+	char **name;
+
+	VA_ARGS_VGET(args, type, name, data);
 	if (this->next)
 	{
 		*type = this->next->type;
@@ -149,7 +154,8 @@ static enumerator_t *endecode_create_enumerator(endecode_test_t *test)
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)endecode_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _endecode_enumerate,
 			.destroy = (void*)free,
 		},
 		.next = test,
diff --git a/src/libcharon/plugins/vici/vici_message.c b/src/libcharon/plugins/vici/vici_message.c
index 58b896773..91d344994 100644
--- a/src/libcharon/plugins/vici/vici_message.c
+++ b/src/libcharon/plugins/vici/vici_message.c
@@ -135,11 +135,16 @@ typedef struct {
 } parse_enumerator_t;
 
 METHOD(enumerator_t, parse_enumerate, bool,
-	parse_enumerator_t *this, vici_type_t *out, char **name, chunk_t *value)
+	parse_enumerator_t *this, va_list args)
 {
+	vici_type_t *out;
+	chunk_t *value;
+	char **name;
 	uint8_t type;
 	chunk_t data;
 
+	VA_ARGS_VGET(args, out, name, value);
+
 	if (!this->reader->remaining(this->reader) ||
 		!this->reader->read_uint8(this->reader, &type))
 	{
@@ -218,7 +223,8 @@ METHOD(vici_message_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_parse_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _parse_enumerate,
 			.destroy = _parse_destroy,
 		},
 		.reader = bio_reader_create(this->encoding),
diff --git a/src/libcharon/sa/child_sa.c b/src/libcharon/sa/child_sa.c
index e1ffc2aae..2a8ef0234 100644
--- a/src/libcharon/sa/child_sa.c
+++ b/src/libcharon/sa/child_sa.c
@@ -435,10 +435,11 @@ struct policy_enumerator_t {
 };
 
 METHOD(enumerator_t, policy_enumerate, bool,
-	   policy_enumerator_t *this, traffic_selector_t **my_out,
-	   traffic_selector_t **other_out)
+	   policy_enumerator_t *this, va_list args)
 {
-	traffic_selector_t *other_ts;
+	traffic_selector_t *other_ts, **my_out, **other_out;
+
+	VA_ARGS_VGET(args, my_out, other_out);
 
 	while (this->ts || this->mine->enumerate(this->mine, &this->ts))
 	{
@@ -487,7 +488,8 @@ METHOD(child_sa_t, create_policy_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_policy_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _policy_enumerate,
 			.destroy = _policy_destroy,
 		},
 		.mine = array_create_enumerator(this->my_ts),
diff --git a/src/libcharon/sa/ike_sa.c b/src/libcharon/sa/ike_sa.c
index 76e10691f..723da72e1 100644
--- a/src/libcharon/sa/ike_sa.c
+++ b/src/libcharon/sa/ike_sa.c
@@ -1699,8 +1699,11 @@ typedef struct {
 } child_enumerator_t;
 
 METHOD(enumerator_t, child_enumerate, bool,
-	child_enumerator_t *this, child_sa_t **child_sa)
+	child_enumerator_t *this, va_list args)
 {
+	child_sa_t **child_sa;
+
+	VA_ARGS_VGET(args, child_sa);
 	if (this->inner->enumerate(this->inner, &this->current))
 	{
 		*child_sa = this->current;
@@ -1723,7 +1726,8 @@ METHOD(ike_sa_t, create_child_sa_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_child_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _child_enumerate,
 			.destroy = _child_enumerator_destroy,
 		},
 		.inner = array_create_enumerator(this->child_sas),
diff --git a/src/libcharon/sa/ike_sa_manager.c b/src/libcharon/sa/ike_sa_manager.c
index 15629fe61..fcb4cf0cd 100644
--- a/src/libcharon/sa/ike_sa_manager.c
+++ b/src/libcharon/sa/ike_sa_manager.c
@@ -513,8 +513,13 @@ struct private_enumerator_t {
 };
 
 METHOD(enumerator_t, enumerate, bool,
-	private_enumerator_t *this, entry_t **entry, u_int *segment)
+	private_enumerator_t *this, va_list args)
 {
+	entry_t **entry;
+	u_int *segment;
+
+	VA_ARGS_VGET(args, entry, segment);
+
 	if (this->entry)
 	{
 		this->entry->condvar->signal(this->entry->condvar);
@@ -572,7 +577,8 @@ static enumerator_t* create_table_enumerator(private_ike_sa_manager_t *this)
 
 	INIT(enumerator,
 		.enumerator = {
-			.enumerate = (void*)_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
 			.destroy = _enumerator_destroy,
 		},
 		.manager = this,
diff --git a/src/libimcv/imc/imc_os_info.c b/src/libimcv/imc/imc_os_info.c
index 3315c209f..a40c30d20 100644
--- a/src/libimcv/imc/imc_os_info.c
+++ b/src/libimcv/imc/imc_os_info.c
@@ -283,23 +283,20 @@ typedef struct {
 
 } package_enumerator_t;
 
-/**
- * Implementation of package_enumerator.destroy.
- */
-static void package_enumerator_destroy(package_enumerator_t *this)
+METHOD(enumerator_t, package_enumerator_destroy, void,
+	package_enumerator_t *this)
 {
 	pclose(this->file);
 	free(this);
 }
 
-/**
- * Implementation of package_enumerator.enumerate
- */
-static bool package_enumerator_enumerate(package_enumerator_t *this, ...)
+METHOD(enumerator_t, package_enumerator_enumerate, bool,
+	package_enumerator_t *this, va_list args)
 {
 	chunk_t *name, *version;
 	u_char *pos;
-	va_list args;
+
+	VA_ARGS_VGET(args, name, version);
 
 	while (TRUE)
 	{
@@ -319,23 +316,16 @@ static bool package_enumerator_enumerate(package_enumerator_t *this, ...)
 		{
 			continue;
 		}
-		va_start(args, this);
-
-		name = va_arg(args, chunk_t*);
 		name->ptr = pos;
 		pos = strchr(pos, '\t');
 		if (!pos)
 		{
-			va_end(args);
 			return FALSE;
 		}
 		name->len = pos++ - name->ptr;
 
-		version = va_arg(args, chunk_t*);
 		version->ptr = pos;
 		version->len = strlen(pos) - 1;
-
-		va_end(args);
 		return TRUE;
 	}
 }
@@ -362,12 +352,14 @@ METHOD(imc_os_info_t, create_package_enumerator, enumerator_t*,
 		return NULL;
 	}
 
-	/* Create a package enumerator instance */
-	enumerator = malloc_thing(package_enumerator_t);
-	enumerator->public.enumerate = (void*)package_enumerator_enumerate;
-	enumerator->public.destroy = (void*)package_enumerator_destroy;
-	enumerator->file = file;
-
+	INIT(enumerator,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _package_enumerator_enumerate,
+			.destroy = _package_enumerator_destroy,
+		},
+		.file = file,
+	);
 	return (enumerator_t*)enumerator;
 }
 
diff --git a/src/libimcv/imv/imv_agent.c b/src/libimcv/imv/imv_agent.c
index d0508624d..e96faa77e 100644
--- a/src/libimcv/imv/imv_agent.c
+++ b/src/libimcv/imv/imv_agent.c
@@ -626,22 +626,13 @@ typedef struct {
 
 } language_enumerator_t;
 
-/**
- * Implementation of language_enumerator.destroy.
- */
-static void language_enumerator_destroy(language_enumerator_t *this)
-{
-	free(this);
-}
-
-/**
- * Implementation of language_enumerator.enumerate
- */
-static bool language_enumerator_enumerate(language_enumerator_t *this, ...)
+METHOD(enumerator_t, language_enumerator_enumerate, bool,
+	language_enumerator_t *this, va_list args)
 {
 	char *pos, *cur_lang, **lang;
 	TNC_UInt32 len;
-	va_list args;
+
+	VA_ARGS_VGET(args, lang);
 
 	if (!this->lang_len)
 	{
@@ -676,11 +667,7 @@ static bool language_enumerator_enumerate(language_enumerator_t *this, ...)
 	}
 	cur_lang[len] = '\0';
 
-	va_start(args, this);
-	lang = va_arg(args, char**);
 	*lang = cur_lang;
-	va_end(args);
-
 	return TRUE;
 }
 
@@ -689,10 +676,13 @@ METHOD(imv_agent_t, create_language_enumerator, enumerator_t*,
 {
 	language_enumerator_t *e;
 
-	/* Create a language enumerator instance */
-	e = malloc_thing(language_enumerator_t);
-	e->public.enumerate = (void*)language_enumerator_enumerate;
-	e->public.destroy = (void*)language_enumerator_destroy;
+	INIT(e,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _language_enumerator_enumerate,
+			.destroy = (void*)free,
+		},
+	);
 
 	if (!this->get_attribute ||
 		!this->get_attribute(this->id, state->get_connection_id(state),
diff --git a/src/libimcv/pts/pts_pcr.c b/src/libimcv/pts/pts_pcr.c
index d514532c5..9f098c08e 100644
--- a/src/libimcv/pts/pts_pcr.c
+++ b/src/libimcv/pts/pts_pcr.c
@@ -111,17 +111,12 @@ typedef struct {
 	private_pts_pcr_t *pcrs;
 } pcr_enumerator_t;
 
-/**
- * Implementation of enumerator.enumerate
- */
-static bool pcr_enumerator_enumerate(pcr_enumerator_t *this, ...)
+METHOD(enumerator_t, pcr_enumerator_enumerate, bool,
+	pcr_enumerator_t *this, va_list args)
 {
-	uint32_t *pcr, i, f;
-	va_list args;
+	uint32_t i, f, *pcr;
 
-	va_start(args, this);
-	pcr = va_arg(args, uint32_t*);
-	va_end(args);
+	VA_ARGS_VGET(args, pcr);
 
 	while (this->pcr <= this->pcrs->pcr_max)
 	{
@@ -148,7 +143,8 @@ METHOD(pts_pcr_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)pcr_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _pcr_enumerator_enumerate,
 			.destroy = (void*)free,
 		},
 		.pcrs = this,
diff --git a/src/libpttls/sasl/sasl_mechanism.c b/src/libpttls/sasl/sasl_mechanism.c
index 05a02e56d..4e54de314 100644
--- a/src/libpttls/sasl/sasl_mechanism.c
+++ b/src/libpttls/sasl/sasl_mechanism.c
@@ -59,8 +59,11 @@ typedef struct {
 } mech_enumerator_t;
 
 METHOD(enumerator_t, mech_enumerate, bool,
-	mech_enumerator_t *this, char **name)
+	mech_enumerator_t *this, va_list args)
 {
+	char **name;
+
+	VA_ARGS_VGET(args, name);
 	while (this->i < countof(mechs))
 	{
 		if (mechs[this->i].server == this->server)
@@ -83,7 +86,8 @@ enumerator_t* sasl_mechanism_create_enumerator(bool server)
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_mech_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _mech_enumerate,
 			.destroy = (void*)free,
 		},
 		.server = server,
diff --git a/src/libradius/radius_message.c b/src/libradius/radius_message.c
index 9705d3b53..51135fbea 100644
--- a/src/libradius/radius_message.c
+++ b/src/libradius/radius_message.c
@@ -244,8 +244,12 @@ typedef struct {
 } attribute_enumerator_t;
 
 METHOD(enumerator_t, attribute_enumerate, bool,
-	attribute_enumerator_t *this, int *type, chunk_t *data)
+	attribute_enumerator_t *this, va_list args)
 {
+	chunk_t *data;
+	int *type;
+
+	VA_ARGS_VGET(args, type, data);
 	if (this->left == 0)
 	{
 		return FALSE;
@@ -275,7 +279,8 @@ METHOD(radius_message_t, create_enumerator, enumerator_t*,
 	}
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_attribute_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _attribute_enumerate,
 			.destroy = (void*)free,
 		},
 		.next = (rattr_t*)this->msg->attributes,
@@ -299,12 +304,14 @@ typedef struct {
 } vendor_enumerator_t;
 
 METHOD(enumerator_t, vendor_enumerate, bool,
-	vendor_enumerator_t *this, int *vendor, int *type, chunk_t *data)
+	vendor_enumerator_t *this, va_list args)
 {
-	chunk_t inner_data;
-	int inner_type;
+	chunk_t inner_data, *data;
+	int inner_type, *vendor, *type;
 	uint8_t type8, len;
 
+	VA_ARGS_VGET(args, vendor, type, data);
+
 	while (TRUE)
 	{
 		if (this->reader)
@@ -354,7 +361,8 @@ METHOD(radius_message_t, create_vendor_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_vendor_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _vendor_enumerate,
 			.destroy = _vendor_destroy,
 		},
 		.inner = create_enumerator(this),
diff --git a/src/libstrongswan/collections/array.c b/src/libstrongswan/collections/array.c
index 69e7df99e..c3dd6e0e9 100644
--- a/src/libstrongswan/collections/array.c
+++ b/src/libstrongswan/collections/array.c
@@ -214,9 +214,11 @@ typedef struct {
 } array_enumerator_t;
 
 METHOD(enumerator_t, enumerate, bool,
-	array_enumerator_t *this, void **out)
+	array_enumerator_t *this, va_list args)
 {
-	void *pos;
+	void *pos, **out;
+
+	VA_ARGS_VGET(args, out);
 
 	if (this->idx >= this->array->count)
 	{
@@ -250,7 +252,8 @@ enumerator_t* array_create_enumerator(array_t *array)
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
 			.destroy = (void*)free,
 		},
 		.array = array,
diff --git a/src/libstrongswan/collections/enumerator.c b/src/libstrongswan/collections/enumerator.c
index e96b235e3..cdf05d5e8 100644
--- a/src/libstrongswan/collections/enumerator.c
+++ b/src/libstrongswan/collections/enumerator.c
@@ -50,22 +50,24 @@ bool enumerator_enumerate_default(enumerator_t *enumerator, ...)
 	return result;
 }
 
-/**
- * Implementation of enumerator_create_empty().enumerate
- */
-static bool enumerate_empty(enumerator_t *enumerator, ...)
+METHOD(enumerator_t, enumerate_empty, bool,
+	enumerator_t *enumerator, va_list args)
 {
 	return FALSE;
 }
 
-/**
- * See header
+/*
+ * Described in header
  */
 enumerator_t* enumerator_create_empty()
 {
-	enumerator_t *this = malloc_thing(enumerator_t);
-	this->enumerate = enumerate_empty;
-	this->destroy = (void*)free;
+	enumerator_t *this;
+
+	INIT(this,
+		.enumerate = enumerator_enumerate_default,
+		.venumerate = _enumerate_empty,
+		.destroy = (void*)free,
+	);
 	return this;
 }
 
@@ -83,32 +85,31 @@ typedef struct {
 	char *full_end;
 } dir_enum_t;
 
-/**
- * Implementation of enumerator_create_directory().destroy
- */
-static void destroy_dir_enum(dir_enum_t *this)
+METHOD(enumerator_t, destroy_dir_enum, void,
+	dir_enum_t *this)
 {
 	closedir(this->dir);
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_directory().enumerate
- */
-static bool enumerate_dir_enum(dir_enum_t *this, char **relative,
-							   char **absolute, struct stat *st)
+METHOD(enumerator_t, enumerate_dir_enum, bool,
+	dir_enum_t *this, va_list args)
 {
 	struct dirent *entry = readdir(this->dir);
+	struct stat *st;
 	size_t remaining;
+	char **relative, **absolute;
 	int len;
 
+	VA_ARGS_VGET(args, relative, absolute, st);
+
 	if (!entry)
 	{
 		return FALSE;
 	}
 	if (streq(entry->d_name, ".") || streq(entry->d_name, ".."))
 	{
-		return enumerate_dir_enum(this, relative, absolute, st);
+		return this->public.enumerate(&this->public, relative, absolute, st);
 	}
 	if (relative)
 	{
@@ -141,15 +142,21 @@ static bool enumerate_dir_enum(dir_enum_t *this, char **relative,
 	return TRUE;
 }
 
-/**
- * See header
+/*
+ * Described in header
  */
 enumerator_t* enumerator_create_directory(const char *path)
 {
+	dir_enum_t *this;
 	int len;
-	dir_enum_t *this = malloc_thing(dir_enum_t);
-	this->public.enumerate = (void*)enumerate_dir_enum;
-	this->public.destroy = (void*)destroy_dir_enum;
+
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_dir_enum,
+			.destroy = _destroy_dir_enum,
+		},
+	);
 
 	if (*path == '\0')
 	{
@@ -171,9 +178,10 @@ enumerator_t* enumerator_create_directory(const char *path)
 	this->full_end = &this->full[len];
 
 	this->dir = opendir(path);
-	if (this->dir == NULL)
+	if (!this->dir)
 	{
-		DBG1(DBG_LIB, "opening directory '%s' failed: %s", path, strerror(errno));
+		DBG1(DBG_LIB, "opening directory '%s' failed: %s", path,
+			 strerror(errno));
 		free(this);
 		return NULL;
 	}
@@ -196,21 +204,21 @@ typedef struct {
 	char full[PATH_MAX];
 } glob_enum_t;
 
-/**
- * Implementation of enumerator_create_glob().destroy
- */
-static void destroy_glob_enum(glob_enum_t *this)
+METHOD(enumerator_t, destroy_glob_enum, void,
+	glob_enum_t *this)
 {
 	globfree(&this->glob);
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_glob().enumerate
- */
-static bool enumerate_glob_enum(glob_enum_t *this, char **file, struct stat *st)
+METHOD(enumerator_t, enumerate_glob_enum, bool,
+	glob_enum_t *this, va_list args)
 {
+	struct stat *st;
 	char *match;
+	char **file;
+
+	VA_ARGS_VGET(args, file, st);
 
 	if (this->pos >= this->glob.gl_pathc)
 	{
@@ -221,20 +229,17 @@ static bool enumerate_glob_enum(glob_enum_t *this, char **file, struct stat *st)
 	{
 		*file = match;
 	}
-	if (st)
+	if (st && stat(match, st))
 	{
-		if (stat(match, st))
-		{
-			DBG1(DBG_LIB, "stat() on '%s' failed: %s", match,
-				 strerror(errno));
-			return FALSE;
-		}
+		DBG1(DBG_LIB, "stat() on '%s' failed: %s", match,
+			 strerror(errno));
+		return FALSE;
 	}
 	return TRUE;
 }
 
-/**
- * See header
+/*
+ * Described in header
  */
 enumerator_t* enumerator_create_glob(const char *pattern)
 {
@@ -248,8 +253,9 @@ enumerator_t* enumerator_create_glob(const char *pattern)
 
 	INIT(this,
 		.public = {
-			.enumerate = (void*)enumerate_glob_enum,
-			.destroy = (void*)destroy_glob_enum,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_glob_enum,
+			.destroy = _destroy_glob_enum,
 		},
 	);
 
@@ -291,24 +297,22 @@ typedef struct {
 	const char *trim;
 } token_enum_t;
 
-/**
- * Implementation of enumerator_create_token().destroy
- */
-static void destroy_token_enum(token_enum_t *this)
+METHOD(enumerator_t, destroy_token_enum, void,
+	token_enum_t *this)
 {
 	free(this->string);
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_token().enumerate
- */
-static bool enumerate_token_enum(token_enum_t *this, char **token)
+METHOD(enumerator_t, enumerate_token_enum, bool,
+	token_enum_t *this, va_list args)
 {
 	const char *sep, *trim;
-	char *pos = NULL, *tmp;
+	char *pos = NULL, *tmp, **token;
 	bool last = FALSE;
 
+	VA_ARGS_VGET(args, token);
+
 	/* trim leading characters/separators */
 	while (*this->pos)
 	{
@@ -409,52 +413,48 @@ static bool enumerate_token_enum(token_enum_t *this, char **token)
 	return FALSE;
 }
 
-/**
- * See header
+/*
+ * Described in header
  */
 enumerator_t* enumerator_create_token(const char *string, const char *sep,
 									  const char *trim)
 {
-	token_enum_t *enumerator = malloc_thing(token_enum_t);
+	token_enum_t *this;
 
-	enumerator->public.enumerate = (void*)enumerate_token_enum;
-	enumerator->public.destroy = (void*)destroy_token_enum;
-	enumerator->string = strdup(string);
-	enumerator->pos = enumerator->string;
-	enumerator->sep = sep;
-	enumerator->trim = trim;
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_token_enum,
+			.destroy = _destroy_token_enum,
+		},
+		.string = strdup(string),
+		.sep = sep,
+		.trim = trim,
+	);
+	this->pos = this->string;
 
-	return &enumerator->public;
+	return &this->public;
 }
 
 /**
- * enumerator for nested enumerations
+ * Enumerator for nested enumerations
  */
 typedef struct {
-	/* implements enumerator_t */
 	enumerator_t public;
-	/* outer enumerator */
 	enumerator_t *outer;
-	/* inner enumerator */
 	enumerator_t *inner;
-	/* constructor for inner enumerator */
 	enumerator_t *(*create_inner)(void *outer, void *data);
-	/* data to pass to constructor above */
 	void *data;
-	/* destructor for data */
-	void (*destroy_data)(void *data);
+	void (*destructor)(void *data);
 } nested_enumerator_t;
 
 
-/**
- * Implementation of enumerator_create_nested().enumerate()
- */
-static bool enumerate_nested(nested_enumerator_t *this, void *v1, void *v2,
-							 void *v3, void *v4, void *v5)
+METHOD(enumerator_t, enumerate_nested, bool,
+	nested_enumerator_t *this, va_list args)
 {
 	while (TRUE)
 	{
-		while (this->inner == NULL)
+		while (!this->inner)
 		{
 			void *outer;
 
@@ -463,8 +463,13 @@ static bool enumerate_nested(nested_enumerator_t *this, void *v1, void *v2,
 				return FALSE;
 			}
 			this->inner = this->create_inner(outer, this->data);
+			if (this->inner && !this->inner->venumerate)
+			{
+				DBG1(DBG_LIB, "!!! ENUMERATE NESTED: venumerate() missing !!!");
+				return FALSE;
+			}
 		}
-		if (this->inner->enumerate(this->inner, v1, v2, v3, v4, v5))
+		if (this->inner->venumerate(this->inner, args))
 		{
 			return TRUE;
 		}
@@ -473,42 +478,43 @@ static bool enumerate_nested(nested_enumerator_t *this, void *v1, void *v2,
 	}
 }
 
-/**
- * Implementation of enumerator_create_nested().destroy()
- **/
-static void destroy_nested(nested_enumerator_t *this)
+METHOD(enumerator_t, destroy_nested, void,
+	nested_enumerator_t *this)
 {
-	if (this->destroy_data)
+	if (this->destructor)
 	{
-		this->destroy_data(this->data);
+		this->destructor(this->data);
 	}
 	DESTROY_IF(this->inner);
 	this->outer->destroy(this->outer);
 	free(this);
 }
 
-/**
- * See header
+/*
+ * Described in header
  */
 enumerator_t *enumerator_create_nested(enumerator_t *outer,
 					enumerator_t *(inner_constructor)(void *outer, void *data),
-					void *data, void (*destroy_data)(void *data))
+					void *data, void (*destructor)(void *data))
 {
-	nested_enumerator_t *enumerator = malloc_thing(nested_enumerator_t);
-
-	enumerator->public.enumerate = (void*)enumerate_nested;
-	enumerator->public.destroy = (void*)destroy_nested;
-	enumerator->outer = outer;
-	enumerator->inner = NULL;
-	enumerator->create_inner = (void*)inner_constructor;
-	enumerator->data = data;
-	enumerator->destroy_data = destroy_data;
+	nested_enumerator_t *this;
 
-	return &enumerator->public;
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_nested,
+			.destroy = _destroy_nested,
+		},
+		.outer = outer,
+		.create_inner = inner_constructor,
+		.data = data,
+		.destructor = destructor,
+	);
+	return &this->public;
 }
 
 /**
- * enumerator for filtered enumerator
+ * Enumerator for filtered enumerator
  */
 typedef struct {
 	enumerator_t public;
@@ -518,10 +524,8 @@ typedef struct {
 	void (*destructor)(void *data);
 } filter_enumerator_t;
 
-/**
- * Implementation of enumerator_create_filter().destroy
- */
-static void destroy_filter(filter_enumerator_t *this)
+METHOD(enumerator_t, destroy_filter, void,
+	filter_enumerator_t *this)
 {
 	if (this->destructor)
 	{
@@ -531,13 +535,14 @@ static void destroy_filter(filter_enumerator_t *this)
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_filter().enumerate
- */
-static bool enumerate_filter(filter_enumerator_t *this, void *o1, void *o2,
-							 void *o3, void *o4, void *o5)
+METHOD(enumerator_t, enumerate_filter, bool,
+	filter_enumerator_t *this, va_list args)
 {
 	void *i1, *i2, *i3, *i4, *i5;
+	void *o1, *o2, *o3, *o4, *o5;
+
+	/* FIXME: what happens if there are less than five arguments is not defined */
+	VA_ARGS_VGET(args, o1, o2, o3, o4, o5);
 
 	while (this->unfiltered->enumerate(this->unfiltered, &i1, &i2, &i3, &i4, &i5))
 	{
@@ -549,27 +554,31 @@ static bool enumerate_filter(filter_enumerator_t *this, void *o1, void *o2,
 	return FALSE;
 }
 
-/**
- * see header
+/*
+ * Described in header
  */
 enumerator_t *enumerator_create_filter(enumerator_t *unfiltered,
 									   bool (*filter)(void *data, ...),
 									   void *data, void (*destructor)(void *data))
 {
-	filter_enumerator_t *this = malloc_thing(filter_enumerator_t);
-
-	this->public.enumerate = (void*)enumerate_filter;
-	this->public.destroy = (void*)destroy_filter;
-	this->unfiltered = unfiltered;
-	this->filter = filter;
-	this->data = data;
-	this->destructor = destructor;
+	filter_enumerator_t *this;
 
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_filter,
+			.destroy = _destroy_filter,
+		},
+		.unfiltered = unfiltered,
+		.filter = filter,
+		.data = data,
+		.destructor = destructor,
+	);
 	return &this->public;
 }
 
 /**
- * enumerator for cleaner enumerator
+ * Enumerator for cleaner enumerator
  */
 typedef struct {
 	enumerator_t public;
@@ -578,44 +587,48 @@ typedef struct {
 	void *data;
 } cleaner_enumerator_t;
 
-/**
- * Implementation of enumerator_create_cleanup().destroy
- */
-static void destroy_cleaner(cleaner_enumerator_t *this)
+METHOD(enumerator_t, destroy_cleaner, void,
+	cleaner_enumerator_t *this)
 {
 	this->cleanup(this->data);
 	this->wrapped->destroy(this->wrapped);
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_cleaner().enumerate
- */
-static bool enumerate_cleaner(cleaner_enumerator_t *this, void *v1, void *v2,
-							  void *v3, void *v4, void *v5)
+METHOD(enumerator_t, enumerate_cleaner, bool,
+	cleaner_enumerator_t *this, va_list args)
 {
-	return this->wrapped->enumerate(this->wrapped, v1, v2, v3, v4, v5);
+	if (!this->wrapped->venumerate)
+	{
+		DBG1(DBG_LIB, "!!! CLEANER ENUMERATOR: venumerate() missing !!!");
+		return FALSE;
+	}
+	return this->wrapped->venumerate(this->wrapped, args);
 }
 
-/**
- * see header
+/*
+ * Described in header
  */
 enumerator_t *enumerator_create_cleaner(enumerator_t *wrapped,
 										void (*cleanup)(void *data), void *data)
 {
-	cleaner_enumerator_t *this = malloc_thing(cleaner_enumerator_t);
-
-	this->public.enumerate = (void*)enumerate_cleaner;
-	this->public.destroy = (void*)destroy_cleaner;
-	this->wrapped = wrapped;
-	this->cleanup = cleanup;
-	this->data = data;
+	cleaner_enumerator_t *this;
 
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_cleaner,
+			.destroy = _destroy_cleaner,
+		},
+		.wrapped = wrapped,
+		.cleanup = cleanup,
+		.data = data,
+	);
 	return &this->public;
 }
 
 /**
- * enumerator for single enumerator
+ * Enumerator for single enumerator
  */
 typedef struct {
 	enumerator_t public;
@@ -624,10 +637,8 @@ typedef struct {
 	bool done;
 } single_enumerator_t;
 
-/**
- * Implementation of enumerator_create_single().destroy
- */
-static void destroy_single(single_enumerator_t *this)
+METHOD(enumerator_t, destroy_single, void,
+	single_enumerator_t *this)
 {
 	if (this->cleanup)
 	{
@@ -636,11 +647,12 @@ static void destroy_single(single_enumerator_t *this)
 	free(this);
 }
 
-/**
- * Implementation of enumerator_create_single().enumerate
- */
-static bool enumerate_single(single_enumerator_t *this, void **item)
+METHOD(enumerator_t, enumerate_single, bool,
+	single_enumerator_t *this, va_list args)
 {
+	void **item;
+
+	VA_ARGS_VGET(args, item);
 	if (this->done)
 	{
 		return FALSE;
@@ -650,18 +662,21 @@ static bool enumerate_single(single_enumerator_t *this, void **item)
 	return TRUE;
 }
 
-/**
- * see header
+/*
+ * Described in header
  */
 enumerator_t *enumerator_create_single(void *item, void (*cleanup)(void *item))
 {
-	single_enumerator_t *this = malloc_thing(single_enumerator_t);
-
-	this->public.enumerate = (void*)enumerate_single;
-	this->public.destroy = (void*)destroy_single;
-	this->item = item;
-	this->cleanup = cleanup;
-	this->done = FALSE;
+	single_enumerator_t *this;
 
+	INIT(this,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_single,
+			.destroy = _destroy_single,
+		},
+		.item = item,
+		.cleanup = cleanup,
+	);
 	return &this->public;
 }
diff --git a/src/libstrongswan/collections/enumerator.h b/src/libstrongswan/collections/enumerator.h
index 224fe7ea8..e4b0547ba 100644
--- a/src/libstrongswan/collections/enumerator.h
+++ b/src/libstrongswan/collections/enumerator.h
@@ -172,17 +172,21 @@ enumerator_t* enumerator_create_token(const char *string, const char *sep,
 /**
  * Creates an enumerator which enumerates over enumerated enumerators :-).
  *
- * The variable argument list of enumeration values is limit to 5.
+ * The outer enumerator is expected to return objects that, when passed to
+ * inner_contructor, will create a new enumerator that will be enumerated until
+ * completion (to this enumerator will the pointer arguments that are passed to
+ * this enumerator be forwarded) at which point a new element from the outer
+ * enumerator is requested to create a new inner enumerator.
  *
  * @param outer					outer enumerator
- * @param inner_constructor		constructor to inner enumerator
+ * @param inner_constructor		constructor to create inner enumerator
  * @param data					data to pass to each inner_constructor call
- * @param destroy_data			destructor to pass to data
+ * @param destructor			destructor function to clean up data after use
  * @return						the nested enumerator
  */
 enumerator_t *enumerator_create_nested(enumerator_t *outer,
 					enumerator_t *(*inner_constructor)(void *outer, void *data),
-					void *data, void (*destroy_data)(void *data));
+					void *data, void (*destructor)(void *data));
 
 /**
  * Creates an enumerator which filters output of another enumerator.
diff --git a/src/libstrongswan/collections/hashtable.c b/src/libstrongswan/collections/hashtable.c
index 2b77a37cc..b0eda9e6a 100644
--- a/src/libstrongswan/collections/hashtable.c
+++ b/src/libstrongswan/collections/hashtable.c
@@ -379,8 +379,13 @@ METHOD(hashtable_t, get_count, u_int,
 }
 
 METHOD(enumerator_t, enumerate, bool,
-	private_enumerator_t *this, const void **key, void **value)
+	private_enumerator_t *this, va_list args)
 {
+	const void **key;
+	void **value;
+
+	VA_ARGS_VGET(args, key, value);
+
 	while (this->count && this->row < this->table->capacity)
 	{
 		this->prev = this->current;
@@ -417,7 +422,8 @@ METHOD(hashtable_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.enumerator = {
-			.enumerate = (void*)_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
 			.destroy = (void*)free,
 		},
 		.table = this,
diff --git a/src/libstrongswan/collections/linked_list.c b/src/libstrongswan/collections/linked_list.c
index b8fe81578..eb11339bc 100644
--- a/src/libstrongswan/collections/linked_list.c
+++ b/src/libstrongswan/collections/linked_list.c
@@ -119,8 +119,12 @@ struct private_enumerator_t {
 };
 
 METHOD(enumerator_t, enumerate, bool,
-	private_enumerator_t *this, void **item)
+	private_enumerator_t *this, va_list args)
 {
+	void **item;
+
+	VA_ARGS_VGET(args, item);
+
 	if (this->finished)
 	{
 		return FALSE;
@@ -152,7 +156,8 @@ METHOD(linked_list_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.enumerator = {
-			.enumerate = (void*)_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
 			.destroy = (void*)free,
 		},
 		.list = this,
diff --git a/src/libstrongswan/credentials/auth_cfg.c b/src/libstrongswan/credentials/auth_cfg.c
index 8a3e659fd..a9c8b3904 100644
--- a/src/libstrongswan/credentials/auth_cfg.c
+++ b/src/libstrongswan/credentials/auth_cfg.c
@@ -146,12 +146,14 @@ typedef struct {
 	bool enumerated[AUTH_RULE_MAX];
 } entry_enumerator_t;
 
-/**
- * enumerate function for item_enumerator_t
- */
-static bool enumerate(entry_enumerator_t *this, auth_rule_t *type, void **value)
+METHOD(enumerator_t, enumerate, bool,
+	entry_enumerator_t *this, va_list args)
 {
+	auth_rule_t *type;
 	entry_t *entry;
+	void **value;
+
+	VA_ARGS_VGET(args, type, value);
 
 	while (this->inner->enumerate(this->inner, &entry))
 	{
@@ -174,10 +176,8 @@ static bool enumerate(entry_enumerator_t *this, auth_rule_t *type, void **value)
 	return FALSE;
 }
 
-/**
- * destroy function for item_enumerator_t
- */
-static void entry_enumerator_destroy(entry_enumerator_t *this)
+METHOD(enumerator_t, entry_enumerator_destroy, void,
+	entry_enumerator_t *this)
 {
 	this->inner->destroy(this->inner);
 	free(this);
@@ -190,8 +190,9 @@ METHOD(auth_cfg_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)enumerate,
-			.destroy = (void*)entry_enumerator_destroy,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
+			.destroy = _entry_enumerator_destroy,
 		},
 		.inner = array_create_enumerator(this->entries),
 	);
diff --git a/src/libstrongswan/credentials/credential_manager.c b/src/libstrongswan/credentials/credential_manager.c
index 8e8be7ef2..5dd8e42b1 100644
--- a/src/libstrongswan/credentials/credential_manager.c
+++ b/src/libstrongswan/credentials/credential_manager.c
@@ -155,8 +155,12 @@ METHOD(credential_manager_t, call_hook, void,
 }
 
 METHOD(enumerator_t, sets_enumerate, bool,
-	sets_enumerator_t *this, credential_set_t **set)
+	sets_enumerator_t *this, va_list args)
 {
+	credential_set_t **set;
+
+	VA_ARGS_VGET(args, set);
+
 	if (this->exclusive)
 	{
 		if (this->exclusive->enumerate(this->exclusive, set))
@@ -202,7 +206,8 @@ static enumerator_t *create_sets_enumerator(private_credential_manager_t *this)
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_sets_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _sets_enumerate,
 			.destroy = _sets_destroy,
 		},
 	);
@@ -840,9 +845,12 @@ typedef struct {
 } trusted_enumerator_t;
 
 METHOD(enumerator_t, trusted_enumerate, bool,
-	trusted_enumerator_t *this, certificate_t **cert, auth_cfg_t **auth)
+	trusted_enumerator_t *this, va_list args)
 {
-	certificate_t *current;
+	certificate_t *current, **cert;
+	auth_cfg_t **auth;
+
+	VA_ARGS_VGET(args, cert, auth);
 
 	DESTROY_IF(this->auth);
 	this->auth = auth_cfg_create();
@@ -931,7 +939,8 @@ METHOD(credential_manager_t, create_trusted_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_trusted_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _trusted_enumerate,
 			.destroy = _trusted_destroy,
 		},
 		.this = this,
@@ -960,9 +969,13 @@ typedef struct {
 } public_enumerator_t;
 
 METHOD(enumerator_t, public_enumerate, bool,
-	public_enumerator_t *this, public_key_t **key, auth_cfg_t **auth)
+	public_enumerator_t *this, va_list args)
 {
 	certificate_t *cert;
+	public_key_t **key;
+	auth_cfg_t **auth;
+
+	VA_ARGS_VGET(args, key, auth);
 
 	while (this->inner->enumerate(this->inner, &cert, auth))
 	{
@@ -1001,7 +1014,8 @@ METHOD(credential_manager_t, create_public_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_public_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _public_enumerate,
 			.destroy = _public_destroy,
 		},
 		.inner = create_trusted_enumerator(this, type, id, online),
diff --git a/src/libstrongswan/credentials/keys/public_key.c b/src/libstrongswan/credentials/keys/public_key.c
index 2c76ad680..87f7e6664 100644
--- a/src/libstrongswan/credentials/keys/public_key.c
+++ b/src/libstrongswan/credentials/keys/public_key.c
@@ -272,8 +272,12 @@ typedef struct  {
 } private_enumerator_t;
 
 METHOD(enumerator_t, signature_schemes_enumerate, bool,
-	private_enumerator_t *this, signature_scheme_t *scheme)
+	private_enumerator_t *this, va_list args)
 {
+	signature_scheme_t *scheme;
+
+	VA_ARGS_VGET(args, scheme);
+
 	while (++this->index < countof(scheme_map))
 	{
 		if (this->type == scheme_map[this->index].type &&
@@ -296,7 +300,8 @@ enumerator_t *signature_schemes_for_key(key_type_t type, int size)
 
 	INIT(this,
 		.public = {
-			.enumerate = (void*)_signature_schemes_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _signature_schemes_enumerate,
 			.destroy = (void*)free,
 		},
 		.index = -1,
diff --git a/src/libstrongswan/credentials/sets/auth_cfg_wrapper.c b/src/libstrongswan/credentials/sets/auth_cfg_wrapper.c
index 8393d5b18..1cd4b9d03 100644
--- a/src/libstrongswan/credentials/sets/auth_cfg_wrapper.c
+++ b/src/libstrongswan/credentials/sets/auth_cfg_wrapper.c
@@ -112,15 +112,15 @@ static bool fetch_cert(wrapper_enumerator_t *enumerator,
 	return TRUE;
 }
 
-/**
- * enumerate function for wrapper_enumerator_t
- */
-static bool enumerate(wrapper_enumerator_t *this, certificate_t **cert)
+METHOD(enumerator_t, enumerate, bool,
+	wrapper_enumerator_t *this, va_list args)
 {
 	auth_rule_t rule;
-	certificate_t *current;
+	certificate_t *current, **cert;
 	public_key_t *public;
 
+	VA_ARGS_VGET(args, cert);
+
 	while (this->inner->enumerate(this->inner, &rule, &current))
 	{
 		if (rule == AUTH_HELPER_IM_HASH_URL ||
@@ -164,10 +164,8 @@ static bool enumerate(wrapper_enumerator_t *this, certificate_t **cert)
 	return FALSE;
 }
 
-/**
- * destroy function for wrapper_enumerator_t
- */
-static void wrapper_enumerator_destroy(wrapper_enumerator_t *this)
+METHOD(enumerator_t, wrapper_enumerator_destroy, void,
+	wrapper_enumerator_t *this)
 {
 	this->inner->destroy(this->inner);
 	free(this);
@@ -183,14 +181,18 @@ METHOD(credential_set_t, create_enumerator, enumerator_t*,
 	{
 		return NULL;
 	}
-	enumerator = malloc_thing(wrapper_enumerator_t);
-	enumerator->auth = this->auth;
-	enumerator->cert = cert;
-	enumerator->key = key;
-	enumerator->id = id;
-	enumerator->inner = this->auth->create_enumerator(this->auth);
-	enumerator->public.enumerate = (void*)enumerate;
-	enumerator->public.destroy = (void*)wrapper_enumerator_destroy;
+	INIT(enumerator,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
+			.destroy = _wrapper_enumerator_destroy,
+		},
+		.auth = this->auth,
+		.cert = cert,
+		.key = key,
+		.id = id,
+		.inner = this->auth->create_enumerator(this->auth),
+	);
 	return &enumerator->public;
 }
 
diff --git a/src/libstrongswan/credentials/sets/callback_cred.c b/src/libstrongswan/credentials/sets/callback_cred.c
index bff33f029..0d72452da 100644
--- a/src/libstrongswan/credentials/sets/callback_cred.c
+++ b/src/libstrongswan/credentials/sets/callback_cred.c
@@ -60,9 +60,12 @@ typedef struct {
 } shared_enumerator_t;
 
 METHOD(enumerator_t, shared_enumerate, bool,
-	shared_enumerator_t *this, shared_key_t **out,
-	id_match_t *match_me, id_match_t *match_other)
+	shared_enumerator_t *this, va_list args)
 {
+	shared_key_t **out;
+	id_match_t *match_me, *match_other;
+
+	VA_ARGS_VGET(args, out, match_me, match_other);
 	DESTROY_IF(this->current);
 	this->current = this->this->cb.shared(this->this->data, this->type,
 								this->me, this->other, match_me, match_other);
@@ -89,7 +92,8 @@ METHOD(credential_set_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_shared_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerate,
 			.destroy = _shared_destroy,
 		},
 		.this = this,
diff --git a/src/libstrongswan/credentials/sets/cert_cache.c b/src/libstrongswan/credentials/sets/cert_cache.c
index 24fdb194b..92d5efdc6 100644
--- a/src/libstrongswan/credentials/sets/cert_cache.c
+++ b/src/libstrongswan/credentials/sets/cert_cache.c
@@ -252,13 +252,14 @@ typedef struct {
 	int locked;
 } cert_enumerator_t;
 
-/**
- * filter function for certs enumerator
- */
-static bool cert_enumerate(cert_enumerator_t *this, certificate_t **out)
+METHOD(enumerator_t, cert_enumerate, bool,
+	cert_enumerator_t *this, va_list args)
 {
 	public_key_t *public;
 	relation_t *rel;
+	certificate_t **out;
+
+	VA_ARGS_VGET(args, out);
 
 	if (this->locked >= 0)
 	{
@@ -311,10 +312,8 @@ static bool cert_enumerate(cert_enumerator_t *this, certificate_t **out)
 	return FALSE;
 }
 
-/**
- * clean up enumeration data
- */
-static void cert_enumerator_destroy(cert_enumerator_t *this)
+METHOD(enumerator_t, cert_enumerator_destroy, void,
+	cert_enumerator_t *this)
 {
 	relation_t *rel;
 
@@ -336,16 +335,19 @@ METHOD(credential_set_t, create_enumerator, enumerator_t*,
 	{
 		return NULL;
 	}
-	enumerator = malloc_thing(cert_enumerator_t);
-	enumerator->public.enumerate = (void*)cert_enumerate;
-	enumerator->public.destroy = (void*)cert_enumerator_destroy;
-	enumerator->cert = cert;
-	enumerator->key = key;
-	enumerator->id = id;
-	enumerator->relations = this->relations;
-	enumerator->index = -1;
-	enumerator->locked = -1;
-
+	INIT(enumerator,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerate,
+			.destroy = _cert_enumerator_destroy,
+		},
+		.cert = cert,
+		.key = key,
+		.id = id,
+		.relations = this->relations,
+		.index = -1,
+		.locked = -1,
+	);
 	return &enumerator->public;
 }
 
diff --git a/src/libstrongswan/credentials/sets/ocsp_response_wrapper.c b/src/libstrongswan/credentials/sets/ocsp_response_wrapper.c
index 151d69216..12d3f8156 100644
--- a/src/libstrongswan/credentials/sets/ocsp_response_wrapper.c
+++ b/src/libstrongswan/credentials/sets/ocsp_response_wrapper.c
@@ -49,14 +49,15 @@ typedef struct {
 	identification_t *id;
 } wrapper_enumerator_t;
 
-/**
- * enumerate function wrapper_enumerator_t
- */
-static bool enumerate(wrapper_enumerator_t *this, certificate_t **cert)
+METHOD(enumerator_t, enumerate, bool,
+	wrapper_enumerator_t *this, va_list args)
 {
-	certificate_t *current;
+	certificate_t *current, **cert;
 	public_key_t *public;
 
+
+	VA_ARGS_VGET(args, cert);
+
 	while (this->inner->enumerate(this->inner, &current))
 	{
 		if (this->cert != CERT_ANY && this->cert != current->get_type(current))
@@ -85,10 +86,8 @@ static bool enumerate(wrapper_enumerator_t *this, certificate_t **cert)
 	return FALSE;
 }
 
-/**
- * destroy function for wrapper_enumerator_t
- */
-static void enumerator_destroy(wrapper_enumerator_t *this)
+METHOD(enumerator_t, enumerator_destroy, void,
+	wrapper_enumerator_t *this)
 {
 	this->inner->destroy(this->inner);
 	free(this);
@@ -105,13 +104,17 @@ METHOD(credential_set_t, create_enumerator, enumerator_t*,
 		return NULL;
 	}
 
-	enumerator = malloc_thing(wrapper_enumerator_t);
-	enumerator->cert = cert;
-	enumerator->key = key;
-	enumerator->id = id;
-	enumerator->inner = this->response->create_cert_enumerator(this->response);
-	enumerator->public.enumerate = (void*)enumerate;
-	enumerator->public.destroy = (void*)enumerator_destroy;
+	INIT(enumerator,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
+			.destroy = _enumerator_destroy,
+		},
+		.cert = cert,
+		.key = key,
+		.id = id,
+		.inner = this->response->create_cert_enumerator(this->response),
+	);
 	return &enumerator->public;
 }
 
diff --git a/src/libstrongswan/crypto/crypto_factory.c b/src/libstrongswan/crypto/crypto_factory.c
index bab59a06f..3414a21bd 100644
--- a/src/libstrongswan/crypto/crypto_factory.c
+++ b/src/libstrongswan/crypto/crypto_factory.c
@@ -1026,9 +1026,14 @@ typedef struct {
 } verify_enumerator_t;
 
 METHOD(enumerator_t, verify_enumerate, bool,
-	verify_enumerator_t *this, u_int *alg, const char **plugin, bool *valid)
+	verify_enumerator_t *this, va_list args)
 {
+	const char **plugin;
 	entry_t *entry;
+	u_int *alg;
+	bool *valid;
+
+	VA_ARGS_VGET(args, alg, plugin, valid);
 
 	if (!this->inner->enumerate(this->inner, &entry))
 	{
@@ -1123,7 +1128,8 @@ METHOD(crypto_factory_t, create_verify_enumerator, enumerator_t*,
 	}
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_verify_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _verify_enumerate,
 			.destroy = _verify_destroy,
 		},
 		.inner = inner,
diff --git a/src/libstrongswan/plugins/mysql/mysql_database.c b/src/libstrongswan/plugins/mysql/mysql_database.c
index 871cc59a0..211eba704 100644
--- a/src/libstrongswan/plugins/mysql/mysql_database.c
+++ b/src/libstrongswan/plugins/mysql/mysql_database.c
@@ -403,10 +403,8 @@ typedef struct {
 	unsigned long *length;
 } mysql_enumerator_t;
 
-/**
- * create a mysql enumerator
- */
-static void mysql_enumerator_destroy(mysql_enumerator_t *this)
+METHOD(enumerator_t, mysql_enumerator_destroy, void,
+	mysql_enumerator_t *this)
 {
 	int columns, i;
 
@@ -434,13 +432,10 @@ static void mysql_enumerator_destroy(mysql_enumerator_t *this)
 	free(this);
 }
 
-/**
- * Implementation of database.query().enumerate
- */
-static bool mysql_enumerator_enumerate(mysql_enumerator_t *this, ...)
+METHOD(enumerator_t, mysql_enumerator_enumerate, bool,
+	mysql_enumerator_t *this, va_list args)
 {
 	int i, columns;
-	va_list args;
 
 	columns = mysql_stmt_field_count(this->stmt);
 
@@ -477,7 +472,6 @@ static bool mysql_enumerator_enumerate(mysql_enumerator_t *this, ...)
 			return FALSE;
 	}
 
-	va_start(args, this);
 	for (i = 0; i < columns; i++)
 	{
 		switch (this->bind[i].buffer_type)
@@ -526,7 +520,6 @@ static bool mysql_enumerator_enumerate(mysql_enumerator_t *this, ...)
 				break;
 		}
 	}
-	va_end(args);
 	return TRUE;
 }
 
@@ -552,9 +545,9 @@ METHOD(database_t, query, enumerator_t*,
 
 		INIT(enumerator,
 			.public = {
-				.enumerate = (void*)mysql_enumerator_enumerate,
-				.destroy = (void*)mysql_enumerator_destroy,
-
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _mysql_enumerator_enumerate,
+				.destroy = _mysql_enumerator_destroy,
 			},
 			.db = this,
 			.stmt = stmt,
diff --git a/src/libstrongswan/plugins/openssl/openssl_crl.c b/src/libstrongswan/plugins/openssl/openssl_crl.c
index 20bac6be5..61cf3e884 100644
--- a/src/libstrongswan/plugins/openssl/openssl_crl.c
+++ b/src/libstrongswan/plugins/openssl/openssl_crl.c
@@ -142,8 +142,14 @@ typedef struct {
 
 
 METHOD(enumerator_t, crl_enumerate, bool,
-	crl_enumerator_t *this, chunk_t *serial, time_t *date, crl_reason_t *reason)
+	crl_enumerator_t *this, va_list args)
 {
+	crl_reason_t *reason;
+	chunk_t *serial;
+	time_t *date;
+
+	VA_ARGS_VGET(args, serial, date, reason);
+
 	if (this->i < this->num)
 	{
 		X509_REVOKED *revoked;
@@ -188,7 +194,8 @@ METHOD(crl_t, create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_crl_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _crl_enumerate,
 			.destroy = (void*)free,
 		},
 		.stack = X509_CRL_get_REVOKED(this->crl),
diff --git a/src/libstrongswan/plugins/openssl/openssl_pkcs7.c b/src/libstrongswan/plugins/openssl/openssl_pkcs7.c
index 5752d96de..83ac8df5b 100644
--- a/src/libstrongswan/plugins/openssl/openssl_pkcs7.c
+++ b/src/libstrongswan/plugins/openssl/openssl_pkcs7.c
@@ -136,8 +136,12 @@ METHOD(enumerator_t, cert_destroy, void,
 }
 
 METHOD(enumerator_t, cert_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **out)
+	cert_enumerator_t *this, va_list args)
 {
+	certificate_t **out;
+
+	VA_ARGS_VGET(args, out);
+
 	if (!this->certs)
 	{
 		return FALSE;
@@ -176,7 +180,8 @@ METHOD(pkcs7_t, create_cert_enumerator, enumerator_t*,
 	{
 		INIT(enumerator,
 			.public = {
-				.enumerate = (void*)_cert_enumerate,
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _cert_enumerate,
 				.destroy = _cert_destroy,
 			},
 			.certs = CMS_get1_certs(this->cms),
@@ -320,8 +325,12 @@ static bool verify_digest(CMS_ContentInfo *cms, CMS_SignerInfo *si, int hash_oid
 }
 
 METHOD(enumerator_t, signature_enumerate, bool,
-	signature_enumerator_t *this, auth_cfg_t **out)
+	signature_enumerator_t *this, va_list args)
 {
+	auth_cfg_t **out;
+
+	VA_ARGS_VGET(args, out);
+
 	if (!this->signers)
 	{
 		return FALSE;
@@ -382,7 +391,8 @@ METHOD(container_t, create_signature_enumerator, enumerator_t*,
 
 		INIT(enumerator,
 			.public = {
-				.enumerate = (void*)_signature_enumerate,
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _signature_enumerate,
 				.destroy = _signature_destroy,
 			},
 			.cms = this->cms,
diff --git a/src/libstrongswan/plugins/pkcs11/pkcs11_library.c b/src/libstrongswan/plugins/pkcs11/pkcs11_library.c
index dc8a1f17a..89ae1969e 100644
--- a/src/libstrongswan/plugins/pkcs11/pkcs11_library.c
+++ b/src/libstrongswan/plugins/pkcs11/pkcs11_library.c
@@ -719,12 +719,14 @@ static bool get_attributes(object_enumerator_t *this, CK_OBJECT_HANDLE object)
 }
 
 METHOD(enumerator_t, object_enumerate, bool,
-	object_enumerator_t *this, CK_OBJECT_HANDLE *out)
+	object_enumerator_t *this, va_list args)
 {
-	CK_OBJECT_HANDLE object;
+	CK_OBJECT_HANDLE object, *out;
 	CK_ULONG found;
 	CK_RV rv;
 
+	VA_ARGS_VGET(args, out);
+
 	if (!this->object)
 	{
 		rv = this->lib->f->C_FindObjects(this->session, &object, 1, &found);
@@ -786,7 +788,8 @@ METHOD(pkcs11_library_t, create_object_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_object_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _object_enumerate,
 			.destroy = _object_destroy,
 		},
 		.session = session,
@@ -806,7 +809,8 @@ METHOD(pkcs11_library_t, create_object_attr_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_object_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _object_enumerate,
 			.destroy = _object_destroy,
 		},
 		.session = session,
@@ -838,11 +842,14 @@ typedef struct {
 } mechanism_enumerator_t;
 
 METHOD(enumerator_t, enumerate_mech, bool,
-	mechanism_enumerator_t *this, CK_MECHANISM_TYPE* type,
-	CK_MECHANISM_INFO *info)
+	mechanism_enumerator_t *this, va_list args)
 {
+	CK_MECHANISM_INFO *info;
+	CK_MECHANISM_TYPE *type;
 	CK_RV rv;
 
+	VA_ARGS_VGET(args, type, info);
+
 	if (this->current >= this->count)
 	{
 		return FALSE;
@@ -876,7 +883,8 @@ METHOD(pkcs11_library_t, create_mechanism_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_mech,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_mech,
 			.destroy = _destroy_mech,
 		},
 		.lib = &this->public,
diff --git a/src/libstrongswan/plugins/pkcs11/pkcs11_manager.c b/src/libstrongswan/plugins/pkcs11/pkcs11_manager.c
index 96c4a180d..31bcb0d25 100644
--- a/src/libstrongswan/plugins/pkcs11/pkcs11_manager.c
+++ b/src/libstrongswan/plugins/pkcs11/pkcs11_manager.c
@@ -265,8 +265,13 @@ typedef struct {
 } token_enumerator_t;
 
 METHOD(enumerator_t, enumerate_token, bool,
-	token_enumerator_t *this, pkcs11_library_t **out, CK_SLOT_ID *slot)
+	token_enumerator_t *this, va_list args)
 {
+	pkcs11_library_t **out;
+	CK_SLOT_ID *slot;
+
+	VA_ARGS_VGET(args, out, slot);
+
 	if (this->current >= this->count)
 	{
 		free(this->slots);
@@ -301,7 +306,8 @@ METHOD(pkcs11_manager_t, create_token_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate_token,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate_token,
 			.destroy = _destroy_token,
 		},
 		.inner = this->libs->create_enumerator(this->libs),
diff --git a/src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c b/src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c
index d224ef3aa..413c3fff5 100644
--- a/src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c
+++ b/src/libstrongswan/plugins/pkcs7/pkcs7_signed_data.c
@@ -179,7 +179,7 @@ typedef struct {
 } signature_enumerator_t;
 
 METHOD(enumerator_t, enumerate, bool,
-	signature_enumerator_t *this, auth_cfg_t **out)
+	signature_enumerator_t *this, va_list args)
 {
 	signerinfo_t *info;
 	signature_scheme_t scheme;
@@ -187,11 +187,13 @@ METHOD(enumerator_t, enumerate, bool,
 	enumerator_t *enumerator;
 	certificate_t *cert;
 	public_key_t *key;
-	auth_cfg_t *auth;
+	auth_cfg_t *auth, **out;
 	chunk_t chunk, hash, content;
 	hasher_t *hasher;
 	bool valid;
 
+	VA_ARGS_VGET(args, out);
+
 	while (this->inner->enumerate(this->inner, &info))
 	{
 		/* clean up previous round */
@@ -300,7 +302,8 @@ METHOD(container_t, create_signature_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _enumerate,
 			.destroy = _enumerator_destroy,
 		},
 		.inner = this->signerinfos->create_enumerator(this->signerinfos),
diff --git a/src/libstrongswan/plugins/sqlite/sqlite_database.c b/src/libstrongswan/plugins/sqlite/sqlite_database.c
index 0a35e3017..9f874212e 100644
--- a/src/libstrongswan/plugins/sqlite/sqlite_database.c
+++ b/src/libstrongswan/plugins/sqlite/sqlite_database.c
@@ -174,10 +174,8 @@ typedef struct {
 	private_sqlite_database_t *database;
 } sqlite_enumerator_t;
 
-/**
- * destroy a sqlite enumerator
- */
-static void sqlite_enumerator_destroy(sqlite_enumerator_t *this)
+METHOD(enumerator_t, sqlite_enumerator_destroy, void,
+	sqlite_enumerator_t *this)
 {
 	sqlite3_finalize(this->stmt);
 	if (!is_threadsave())
@@ -188,13 +186,10 @@ static void sqlite_enumerator_destroy(sqlite_enumerator_t *this)
 	free(this);
 }
 
-/**
- * Implementation of database.query().enumerate
- */
-static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
+METHOD(enumerator_t, sqlite_enumerator_enumerate, bool,
+	sqlite_enumerator_t *this, va_list args)
 {
 	int i;
-	va_list args;
 
 	switch (sqlite3_step(this->stmt))
 	{
@@ -207,7 +202,7 @@ static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
 		case SQLITE_DONE:
 			return FALSE;
 	}
-	va_start(args, this);
+
 	for (i = 0; i < this->count; i++)
 	{
 		switch (this->columns[i])
@@ -245,11 +240,9 @@ static bool sqlite_enumerator_enumerate(sqlite_enumerator_t *this, ...)
 			}
 			default:
 				DBG1(DBG_LIB, "invalid result type supplied");
-				va_end(args);
 				return FALSE;
 		}
 	}
-	va_end(args);
 	return TRUE;
 }
 
@@ -270,13 +263,17 @@ METHOD(database_t, query, enumerator_t*,
 	stmt = run(this, sql, &args);
 	if (stmt)
 	{
-		enumerator = malloc_thing(sqlite_enumerator_t);
-		enumerator->public.enumerate = (void*)sqlite_enumerator_enumerate;
-		enumerator->public.destroy = (void*)sqlite_enumerator_destroy;
-		enumerator->stmt = stmt;
-		enumerator->count = sqlite3_column_count(stmt);
+		INIT(enumerator,
+			.public = {
+				.enumerate = enumerator_enumerate_default,
+				.venumerate = _sqlite_enumerator_enumerate,
+				.destroy = _sqlite_enumerator_destroy,
+			},
+			.stmt = stmt,
+			.count = sqlite3_column_count(stmt),
+			.database = this,
+		);
 		enumerator->columns = malloc(sizeof(db_type_t) * enumerator->count);
-		enumerator->database = this;
 		for (i = 0; i < enumerator->count; i++)
 		{
 			enumerator->columns[i] = va_arg(args, db_type_t);
diff --git a/src/libstrongswan/settings/settings.c b/src/libstrongswan/settings/settings.c
index b00e8190c..bef51800e 100644
--- a/src/libstrongswan/settings/settings.c
+++ b/src/libstrongswan/settings/settings.c
@@ -744,10 +744,8 @@ typedef struct {
 	hashtable_t *seen;
 } enumerator_data_t;
 
-/**
- * Destroy enumerator data
- */
-static void enumerator_destroy(enumerator_data_t *this)
+CALLBACK(enumerator_destroy, void,
+	enumerator_data_t *this)
 {
 	this->settings->lock->unlock(this->settings->lock);
 	this->seen->destroy(this->seen);
diff --git a/src/libstrongswan/utils/backtrace.c b/src/libstrongswan/utils/backtrace.c
index 6dd68d60e..18b19166e 100644
--- a/src/libstrongswan/utils/backtrace.c
+++ b/src/libstrongswan/utils/backtrace.c
@@ -668,8 +668,12 @@ typedef struct {
 } frame_enumerator_t;
 
 METHOD(enumerator_t, frame_enumerate, bool,
-	frame_enumerator_t *this, void **addr)
+	frame_enumerator_t *this, va_list args)
 {
+	void **addr;
+
+	VA_ARGS_VGET(args, addr);
+
 	if (this->i < this->bt->frame_count)
 	{
 		*addr = this->bt->frames[this->i++];
@@ -685,7 +689,8 @@ METHOD(backtrace_t, create_frame_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_frame_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _frame_enumerate,
 			.destroy = (void*)free,
 		},
 		.bt = this,
diff --git a/src/libstrongswan/utils/identification.c b/src/libstrongswan/utils/identification.c
index 384bd6c92..1a4769063 100644
--- a/src/libstrongswan/utils/identification.c
+++ b/src/libstrongswan/utils/identification.c
@@ -136,9 +136,12 @@ typedef struct {
 } rdn_enumerator_t;
 
 METHOD(enumerator_t, rdn_enumerate, bool,
-	rdn_enumerator_t *this, chunk_t *oid, u_char *type, chunk_t *data)
+	rdn_enumerator_t *this, va_list args)
 {
-	chunk_t rdn;
+	chunk_t rdn, *oid, *data;
+	u_char *type;
+
+	VA_ARGS_VGET(args, oid, type, data);
 
 	/* a DN contains one or more SET, each containing one or more SEQUENCES,
 	 * each containing a OID/value RDN */
@@ -173,7 +176,8 @@ static enumerator_t* create_rdn_enumerator(chunk_t dn)
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_rdn_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _rdn_enumerate,
 			.destroy = (void*)free,
 		},
 	);
@@ -199,10 +203,11 @@ typedef struct {
 } rdn_part_enumerator_t;
 
 METHOD(enumerator_t, rdn_part_enumerate, bool,
-	rdn_part_enumerator_t *this, id_part_t *type, chunk_t *data)
+	rdn_part_enumerator_t *this, va_list args)
 {
 	int i, known_oid, strtype;
-	chunk_t oid, inner_data;
+	chunk_t oid, inner_data, *data;
+	id_part_t *type;
 	static const struct {
 		int oid;
 		id_part_t type;
@@ -228,6 +233,8 @@ METHOD(enumerator_t, rdn_part_enumerate, bool,
 		{OID_EMPLOYEE_NUMBER,	ID_PART_RDN_EN},
 	};
 
+	VA_ARGS_VGET(args, type, data);
+
 	while (this->inner->enumerate(this->inner, &oid, &strtype, &inner_data))
 	{
 		known_oid = asn1_known_oid(oid);
@@ -263,7 +270,8 @@ METHOD(identification_t, create_part_enumerator, enumerator_t*,
 			INIT(e,
 				.inner = create_rdn_enumerator(this->encoded),
 				.public = {
-					.enumerate = (void*)_rdn_part_enumerate,
+					.enumerate = enumerator_enumerate_default,
+					.venumerate = _rdn_part_enumerate,
 					.destroy = _rdn_part_enumerator_destroy,
 				},
 			);
diff --git a/src/manager/xml.c b/src/manager/xml.c
index bf5bbbf05..0aee5f69b 100644
--- a/src/manager/xml.c
+++ b/src/manager/xml.c
@@ -67,8 +67,13 @@ typedef struct {
 } child_enum_t;
 
 METHOD(enumerator_t, child_enumerate, bool,
-	child_enum_t *e, private_xml_t **child, char **name, char **value)
+	child_enum_t *e, va_list args)
 {
+	private_xml_t **child;
+	char **name, **value;
+
+	VA_ARGS_VGET(args, child, name, value);
+
 	while (e->node && e->node->type != XML_ELEMENT_NODE)
 	{
 		e->node = e->node->next;
@@ -120,7 +125,8 @@ METHOD(xml_t, children, enumerator_t*,
 	child_enum_t *ce;
 	INIT(ce,
 		.e = {
-			.enumerate = (void*)_child_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _child_enumerate,
 			.destroy = _child_destroy,
 		},
 		.child = {
diff --git a/src/starter/parser/conf_parser.c b/src/starter/parser/conf_parser.c
index 6d1c54d20..9f71a0584 100644
--- a/src/starter/parser/conf_parser.c
+++ b/src/starter/parser/conf_parser.c
@@ -158,10 +158,13 @@ typedef struct {
 } dictionary_enumerator_t;
 
 METHOD(enumerator_t, dictionary_enumerate, bool,
-	dictionary_enumerator_t *this, char **key, char **value)
+	dictionary_enumerator_t *this, va_list args)
 {
 	setting_t *setting;
 	section_t *parent;
+	char **key, **value;
+
+	VA_ARGS_VGET(args, key, value);
 
 	while (TRUE)
 	{
@@ -221,7 +224,8 @@ METHOD(dictionary_t, dictionary_create_enumerator, enumerator_t*,
 
 	INIT(enumerator,
 		.public = {
-			.enumerate = (void*)_dictionary_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _dictionary_enumerate,
 			.destroy = _dictionary_enumerator_destroy,
 		},
 		.seen = hashtable_create(hashtable_hash_str, hashtable_equals_str, 8),