diff --git a/src/libcharon/encoding/message.c b/src/libcharon/encoding/message.c
index 31f8c14aa0..2fdbeb6076 100644
--- a/src/libcharon/encoding/message.c
+++ b/src/libcharon/encoding/message.c
@@ -23,6 +23,7 @@
 #include "message.h"
 
 #include <library.h>
+#include <bio/bio_writer.h>
 #include <collections/array.h>
 #include <daemon.h>
 #include <sa/ikev1/keymat_v1.h>
@@ -66,6 +67,11 @@
  */
 #define MAX_NAT_D_PAYLOADS 10
 
+/**
+ * Maximum packet size for fragmented packets (same as in sockets)
+ */
+#define MAX_PACKET 10000
+
 /**
  * A payload rule defines the rules for a payload
  * in a specific message rule. It defines if and how
@@ -804,6 +810,29 @@ static message_rule_t message_rules[] = {
 #endif /* USE_IKEV1 */
 };
 
+/**
+ * Data for fragment reassembly.
+ */
+typedef struct {
+
+	/**
+	 * For IKEv1 the number of the last fragment (in case we receive them out
+	 * of order), since the first one starts with 1 this defines the number of
+	 * fragments we expect.
+	 */
+	u_int8_t last;
+
+	/**
+	 * Length of all currently received fragments.
+	 */
+	size_t len;
+
+	/**
+	 * Maximum length of a fragmented packet.
+	 */
+	size_t max_packet;
+
+} fragment_data_t;
 
 typedef struct private_message_t private_message_t;
 
@@ -879,6 +908,7 @@ struct private_message_t {
 
 	/**
 	 * Array of generated fragments (if any), as packet_t*.
+	 * If defragmenting (frag != NULL) this contains fragment_t*
 	 */
 	array_t *fragments;
 
@@ -896,8 +926,41 @@ struct private_message_t {
 	 * The message rule for this message instance
 	 */
 	message_rule_t *rule;
+
+	/**
+	 * Data used to reassemble a fragmented message
+	 */
+	fragment_data_t *frag;
 };
 
+/**
+ * A single fragment within a fragmented message
+ */
+typedef struct {
+
+	/** fragment number */
+	u_int8_t num;
+
+	/** fragment data */
+	chunk_t data;
+
+} fragment_t;
+
+static void fragment_destroy(fragment_t *this)
+{
+	chunk_free(&this->data);
+	free(this);
+}
+
+static void reset_defrag(private_message_t *this, u_int16_t id)
+{
+	array_destroy_function(this->fragments, (void*)fragment_destroy, NULL);
+	this->fragments = NULL;
+	this->message_id = id;
+	this->frag->last = 0;
+	this->frag->len = 0;
+}
+
 /**
  * Get the message rule that applies to this message
  */
@@ -1877,7 +1940,7 @@ METHOD(message_t, parse_header, status_t,
 	this->first_payload = ike_header->payload_interface.get_next_type(
 												&ike_header->payload_interface);
 	if (this->first_payload == PLV1_FRAGMENT && this->is_encrypted)
-	{	/* racoon sets the encryted bit when sending a fragment, but these
+	{	/* racoon sets the encrypted bit when sending a fragment, but these
 		 * messages are really not encrypted */
 		this->is_encrypted = FALSE;
 	}
@@ -2307,14 +2370,121 @@ METHOD(message_t, parse_body, status_t,
 	return SUCCESS;
 }
 
+METHOD(message_t, add_fragment, status_t,
+	private_message_t *this, message_t *message)
+{
+	fragment_payload_t *payload;
+	fragment_t *fragment;
+	bio_writer_t *writer;
+	host_t *src, *dst;
+	chunk_t data;
+	u_int8_t num;
+	int i, insert_at = -1;
+
+	if (!this->frag)
+	{
+		return INVALID_STATE;
+	}
+	payload = (fragment_payload_t*)message->get_payload(message, PLV1_FRAGMENT);
+	if (!payload)
+	{
+		return INVALID_ARG;
+	}
+	if (!this->fragments || this->message_id != payload->get_id(payload))
+	{
+		reset_defrag(this, payload->get_id(payload));
+		/* we don't know the total number of fragments */
+		this->fragments = array_create(0, 0);
+	}
+
+	num = payload->get_number(payload);
+	if (!this->frag->last && payload->is_last(payload))
+	{
+		this->frag->last = num;
+	}
+
+	for (i = 0; i < array_count(this->fragments); i++)
+	{
+		array_get(this->fragments, i, &fragment);
+		if (fragment->num == num)
+		{
+			/* ignore a duplicate fragment */
+			DBG1(DBG_ENC, "received duplicate fragment #%hhu", num);
+			return NEED_MORE;
+		}
+		if (fragment->num > num)
+		{
+			insert_at = i;
+			break;
+		}
+	}
+	data = payload->get_data(payload);
+	this->frag->len += data.len;
+	if (this->frag->len > this->frag->max_packet)
+	{
+		DBG1(DBG_ENC, "fragmented IKE message is too large");
+		reset_defrag(this, 0);
+		return FAILED;
+	}
+	INIT(fragment,
+		.num = num,
+		.data = chunk_clone(data),
+	);
+	array_insert(this->fragments, insert_at, fragment);
+
+	if (this->frag->last < array_count(this->fragments))
+	{
+		/* there are some fragments missing */
+		DBG1(DBG_ENC, "received fragment #%hhu, waiting for complete IKE "
+			 "message", num);
+		return NEED_MORE;
+	}
+
+	writer = bio_writer_create(this->frag->len);
+	DBG1(DBG_ENC, "received fragment #%hhu, reassembling fragmented IKE "
+		 "message", num);
+
+	for (i = 0; i < array_count(this->fragments); i++)
+	{
+		array_get(this->fragments, i, &fragment);
+		writer->write_data(writer, fragment->data);
+	}
+	src = message->get_source(message);
+	dst = message->get_destination(message);
+	this->packet->set_source(this->packet, src->clone(src));
+	this->packet->set_destination(this->packet, dst->clone(dst));
+	this->packet->set_data(this->packet, writer->extract_buf(writer));
+	writer->destroy(writer);
+	this->parser->destroy(this->parser);
+	this->parser = parser_create(this->packet->get_data(this->packet));
+	reset_defrag(this, 0);
+	free(this->frag);
+	this->frag = NULL;
+
+	if (parse_header(this) != SUCCESS)
+	{
+		DBG1(DBG_IKE, "failed to parse header of reassembled IKE message");
+		return FAILED;
+	}
+	return SUCCESS;
+}
+
 METHOD(message_t, destroy, void,
 	private_message_t *this)
 {
 	DESTROY_IF(this->ike_sa_id);
 	this->payloads->destroy_offset(this->payloads, offsetof(payload_t, destroy));
-	array_destroy_offset(this->fragments, offsetof(packet_t, destroy));
 	this->packet->destroy(this->packet);
 	this->parser->destroy(this->parser);
+	if (this->frag)
+	{
+		reset_defrag(this, 0);
+		free(this->frag);
+	}
+	else
+	{
+		array_destroy_offset(this->fragments, offsetof(packet_t, destroy));
+	}
 	free(this);
 }
 
@@ -2352,6 +2522,7 @@ message_t *message_create_from_packet(packet_t *packet)
 			.is_encoded = _is_encoded,
 			.is_fragmented = _is_fragmented,
 			.fragment = _fragment,
+			.add_fragment = _add_fragment,
 			.set_source = _set_source,
 			.get_source = _get_source,
 			.set_destination = _set_destination,
@@ -2390,3 +2561,24 @@ message_t *message_create(int major, int minor)
 
 	return this;
 }
+
+/*
+ * Described in header.
+ */
+message_t *message_create_defrag(message_t *fragment)
+{
+	private_message_t *this;
+
+	if (!fragment->get_payload(fragment, PLV1_FRAGMENT))
+	{
+		return NULL;
+	}
+	this = (private_message_t*)message_create(
+										fragment->get_major_version(fragment),
+										fragment->get_minor_version(fragment));
+	INIT(this->frag,
+		.max_packet = lib->settings->get_int(lib->settings,
+										"%s.max_packet", MAX_PACKET, lib->ns),
+	);
+	return &this->public;
+}
diff --git a/src/libcharon/encoding/message.h b/src/libcharon/encoding/message.h
index e8db51ce5f..69a8e93b1f 100644
--- a/src/libcharon/encoding/message.h
+++ b/src/libcharon/encoding/message.h
@@ -296,6 +296,26 @@ struct message_t {
 	 */
 	bool (*is_fragmented)(message_t *this);
 
+	/**
+	 * Add a fragment to the message if it was created with
+	 * message_create_defrag().
+	 *
+	 * Once the message is completed it should be processed like any other
+	 * inbound message.
+	 *
+	 * @note Only supported for IKEv1 at the moment.
+	 *
+	 * @param fragment	fragment to add
+	 * @return
+	 *					- SUCCESS if message was reassembled
+	 *					- NEED_MORE if not all fragments have yet been received
+	 *					- FAILED if reassembling failed
+	 *					- INVALID_ARG if fragment is invalid for some reason
+	 *					- INVALID_STATE if message was not created using
+	 *					  message_create_defrag()
+	 */
+	status_t (*add_fragment)(message_t *this, message_t *fragment);
+
 	/**
 	 * Gets the source host informations.
 	 *
@@ -419,4 +439,14 @@ message_t *message_create_from_packet(packet_t *packet);
  */
 message_t *message_create(int major, int minor);
 
+/**
+ * Creates a message_t object that is used to reassemble fragmented messages.
+ *
+ * Use add_fragment() to add fragments.
+ *
+ * @param fragment		initial fragment (is not added)
+ * @return				message_t object, NULL if fragment is not actually one
+ */
+message_t *message_create_defrag(message_t *fragment);
+
 #endif /** MESSAGE_H_ @}*/
diff --git a/src/libcharon/sa/ikev1/task_manager_v1.c b/src/libcharon/sa/ikev1/task_manager_v1.c
index 498d6c47ab..0f8e8bc6dd 100644
--- a/src/libcharon/sa/ikev1/task_manager_v1.c
+++ b/src/libcharon/sa/ikev1/task_manager_v1.c
@@ -38,8 +38,6 @@
 #include <processing/jobs/dpd_timeout_job.h>
 #include <processing/jobs/process_message_job.h>
 
-#include <encoding/payloads/fragment_payload.h>
-#include <bio/bio_writer.h>
 #include <collections/array.h>
 
 /**
@@ -51,11 +49,6 @@
  */
 #define MAX_OLD_HASHES 2
 
-/**
- * Maximum packet size for fragmented packets (same as in sockets)
- */
-#define MAX_PACKET 10000
-
 /**
  * First sequence number of responding packets.
  *
@@ -177,38 +170,9 @@ struct private_task_manager_t {
 	} initiating;
 
 	/**
-	 * Data used to reassemble a fragmented message
+	 * Message we are currently defragmenting, if any (only one at a time)
 	 */
-	struct {
-
-		/**
-		 * Fragment ID (currently only one is supported at a time)
-		 */
-		u_int16_t id;
-
-		/**
-		 * The number of the last fragment (in case we receive the fragments out
-		 * of order), since the first starts with 1 this defines the number of
-		 * fragments we expect
-		 */
-		u_int8_t last;
-
-		/**
-		 * List of fragments (fragment_t*)
-		 */
-		linked_list_t *list;
-
-		/**
-		 * Length of all currently received fragments
-		 */
-		size_t len;
-
-		/**
-		 * Maximum length of a fragmented packet
-		 */
-		size_t max_packet;
-
-	} frag;
+	message_t *defrag;
 
 	/**
 	 * List of queued tasks not yet in action
@@ -256,34 +220,6 @@ struct private_task_manager_t {
 	u_int32_t dpd_recv;
 };
 
-/**
- * A single fragment within a fragmented message
- */
-typedef struct {
-
-	/** fragment number */
-	u_int8_t num;
-
-	/** fragment data */
-	chunk_t data;
-
-} fragment_t;
-
-static void fragment_destroy(fragment_t *this)
-{
-	chunk_free(&this->data);
-	free(this);
-}
-
-static void clear_fragments(private_task_manager_t *this, u_int16_t id)
-{
-	DESTROY_FUNCTION_IF(this->frag.list, (void*)fragment_destroy);
-	this->frag.list = NULL;
-	this->frag.last = 0;
-	this->frag.len = 0;
-	this->frag.id = id;
-}
-
 /**
  * Reset retransmission packet list
  */
@@ -1182,107 +1118,23 @@ static status_t process_response(private_task_manager_t *this,
 
 static status_t handle_fragment(private_task_manager_t *this, message_t *msg)
 {
-	fragment_payload_t *payload;
-	enumerator_t *enumerator;
-	fragment_t *fragment;
-	status_t status = SUCCESS;
-	chunk_t data;
-	u_int8_t num;
+	status_t status;
 
-	payload = (fragment_payload_t*)msg->get_payload(msg, PLV1_FRAGMENT);
-	if (!payload)
+	if (!this->defrag)
 	{
-		return FAILED;
-	}
-
-	if (!this->frag.list || this->frag.id != payload->get_id(payload))
-	{
-		clear_fragments(this, payload->get_id(payload));
-		this->frag.list = linked_list_create();
-	}
-
-	num = payload->get_number(payload);
-	if (!this->frag.last && payload->is_last(payload))
-	{
-		this->frag.last = num;
-	}
-
-	enumerator = this->frag.list->create_enumerator(this->frag.list);
-	while (enumerator->enumerate(enumerator, &fragment))
-	{
-		if (fragment->num == num)
-		{	/* ignore a duplicate fragment */
-			DBG1(DBG_IKE, "received duplicate fragment #%hhu", num);
-			enumerator->destroy(enumerator);
-			return NEED_MORE;
-		}
-		if (fragment->num > num)
+		this->defrag = message_create_defrag(msg);
+		if (!this->defrag)
 		{
-			break;
+			return FAILED;
 		}
 	}
-
-	data = payload->get_data(payload);
-	this->frag.len += data.len;
-	if (this->frag.len > this->frag.max_packet)
+	status = this->defrag->add_fragment(this->defrag, msg);
+	if (status == SUCCESS)
 	{
-		DBG1(DBG_IKE, "fragmented IKE message is too large");
-		enumerator->destroy(enumerator);
-		clear_fragments(this, 0);
-		return FAILED;
-	}
-
-	INIT(fragment,
-		.num = num,
-		.data = chunk_clone(data),
-	);
-
-	this->frag.list->insert_before(this->frag.list, enumerator, fragment);
-	enumerator->destroy(enumerator);
-
-	if (this->frag.list->get_count(this->frag.list) == this->frag.last)
-	{
-		message_t *message;
-		packet_t *pkt;
-		host_t *src, *dst;
-		bio_writer_t *writer;
-
-		writer = bio_writer_create(this->frag.len);
-		DBG1(DBG_IKE, "received fragment #%hhu, reassembling fragmented IKE "
-			 "message", num);
-		enumerator = this->frag.list->create_enumerator(this->frag.list);
-		while (enumerator->enumerate(enumerator, &fragment))
-		{
-			writer->write_data(writer, fragment->data);
-		}
-		enumerator->destroy(enumerator);
-
-		src = msg->get_source(msg);
-		dst = msg->get_destination(msg);
-		pkt = packet_create_from_data(src->clone(src), dst->clone(dst),
-									  writer->extract_buf(writer));
-		writer->destroy(writer);
-
-		message = message_create_from_packet(pkt);
-		if (message->parse_header(message) != SUCCESS)
-		{
-			DBG1(DBG_IKE, "failed to parse header of reassembled IKE message");
-			message->destroy(message);
-			status = FAILED;
-		}
-		else
-		{
-			lib->processor->queue_job(lib->processor,
-								(job_t*)process_message_job_create(message));
-			status = NEED_MORE;
-
-		}
-		clear_fragments(this, 0);
-	}
-	else
-	{	/* there are some fragments missing */
-		DBG1(DBG_IKE, "received fragment #%hhu, waiting for complete IKE "
-			 "message", num);
+		lib->processor->queue_job(lib->processor,
+							(job_t*)process_message_job_create(this->defrag));
+		this->defrag = NULL;
+		/* do not process the last fragment */
 		status = NEED_MORE;
 	}
 	return status;
@@ -1912,7 +1764,8 @@ METHOD(task_manager_t, reset, void,
 	this->initiating.seqnr = 0;
 	this->initiating.retransmitted = 0;
 	this->initiating.type = EXCHANGE_TYPE_UNDEFINED;
-	clear_fragments(this, 0);
+	DESTROY_IF(this->defrag);
+	this->defrag = NULL;
 	if (initiate != UINT_MAX)
 	{
 		this->dpd_send = initiate;
@@ -1963,7 +1816,7 @@ METHOD(task_manager_t, destroy, void,
 	this->active_tasks->destroy(this->active_tasks);
 	this->queued_tasks->destroy(this->queued_tasks);
 	this->passive_tasks->destroy(this->passive_tasks);
-	clear_fragments(this, 0);
+	DESTROY_IF(this->defrag);
 
 	DESTROY_IF(this->queued);
 	clear_packets(this->responding.packets);
@@ -2014,10 +1867,6 @@ task_manager_v1_t *task_manager_v1_create(ike_sa_t *ike_sa)
 		.responding = {
 			.seqnr = RESPONDING_SEQ,
 		},
-		.frag = {
-			.max_packet = lib->settings->get_int(lib->settings,
-						"%s.max_packet", MAX_PACKET, lib->ns),
-		},
 		.ike_sa = ike_sa,
 		.rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
 		.queued_tasks = linked_list_create(),