/*
 * Copyright (C) 2007-2019 Tobias Brunner
 * Copyright (C) 2007-2010 Martin Willi
 * Copyright (C) 2023 Andreas Steffen, strongSec GmbH

 * Copyright (C) secunet Security Networks AG
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include "task_manager_v2.h"

#include <math.h>

#include <collections/array.h>
#include <daemon.h>
#include <sa/ikev2/tasks/ike_init.h>
#include <sa/ikev2/tasks/ike_natd.h>
#include <sa/ikev2/tasks/ike_mobike.h>
#include <sa/ikev2/tasks/ike_auth.h>
#include <sa/ikev2/tasks/ike_auth_lifetime.h>
#include <sa/ikev2/tasks/ike_cert_pre.h>
#include <sa/ikev2/tasks/ike_cert_post.h>
#include <sa/ikev2/tasks/ike_rekey.h>
#include <sa/ikev2/tasks/ike_reauth.h>
#include <sa/ikev2/tasks/ike_reauth_complete.h>
#include <sa/ikev2/tasks/ike_redirect.h>
#include <sa/ikev2/tasks/ike_delete.h>
#include <sa/ikev2/tasks/ike_config.h>
#include <sa/ikev2/tasks/ike_dpd.h>
#include <sa/ikev2/tasks/ike_mid_sync.h>
#include <sa/ikev2/tasks/ike_vendor.h>
#include <sa/ikev2/tasks/ike_verify_peer_cert.h>
#include <sa/ikev2/tasks/ike_establish.h>
#include <sa/ikev2/tasks/child_create.h>
#include <sa/ikev2/tasks/child_rekey.h>
#include <sa/ikev2/tasks/child_delete.h>
#include <encoding/payloads/encrypted_fragment_payload.h>
#include <encoding/payloads/delete_payload.h>
#include <encoding/payloads/unknown_payload.h>
#include <processing/jobs/retransmit_job.h>
#include <processing/jobs/delete_ike_sa_job.h>
#include <processing/jobs/initiate_tasks_job.h>

#ifdef ME
#include <sa/ikev2/tasks/ike_me.h>
#endif

typedef struct private_task_manager_t private_task_manager_t;
typedef struct queued_task_t queued_task_t;

/**
 * private data of the task manager
 */
struct private_task_manager_t {

	/**
	 * public functions
	 */
	task_manager_v2_t public;

	/**
	 * associated IKE_SA we are serving
	 */
	ike_sa_t *ike_sa;

	/**
	 * Exchange we are currently handling as responder
	 */
	struct {
		/**
		 * Message ID of the exchange
		 */
		uint32_t mid;

		/**
		 * Helper to defragment the request
		 */
		message_t *defrag;

		/**
		 * Hash of the current message, or its first fragment
		 */
		uint8_t hash[HASH_SIZE_SHA1];

		/**
		 * Packet(s) for retransmissions (mid-1)
		 */
		array_t *packets;

		/**
		 * Hash of the previously received message, or its first fragment
		 */
		uint8_t prev_hash[HASH_SIZE_SHA1];

	} responding;

	/**
	 * Exchange we are currently handling as initiator
	 */
	struct {
		/**
		 * Message ID of the exchange
		 */
		uint32_t mid;

		/**
		 * how many times we have retransmitted so far
		 */
		u_int retransmitted;

		/**
		 * TRUE if any retransmits have been sent for this message (counter is
		 * reset if deferred)
		 */
		bool retransmit_sent;

		/**
		 * packet(s) for retransmission
		 */
		array_t *packets;

		/**
		 * type of the initiated exchange
		 */
		exchange_type_t type;

		/**
		 * TRUE if exchange was deferred because no path was available
		 */
		bool deferred;

		/**
		 * Helper to defragment the response
		 */
		message_t *defrag;

	} initiating;

	/**
	 * Array of queued tasks not yet in action
	 */
	array_t *queued_tasks;

	/**
	 * Array of active tasks, initiated by ourselves
	 */
	array_t *active_tasks;

	/**
	 * Array of tasks initiated by peer
	 */
	array_t *passive_tasks;

	/**
	 * the task manager has been reset
	 */
	bool reset;

	/**
	 * Retransmission settings.
	 */
	retransmission_t retransmit;

	/**
	 * Use make-before-break instead of break-before-make reauth?
	 */
	bool make_before_break;
};

/**
 * Queued tasks
 */
struct queued_task_t {

	/**
	 * Queued task
	 */
	task_t *task;

	/**
	 * Time before which the task is not to be initiated
	 */
	timeval_t time;
};

/**
 * Reset retransmission packet list
 */
static void clear_packets(array_t *array)
{
	packet_t *packet;

	while (array_remove(array, ARRAY_TAIL, &packet))
	{
		packet->destroy(packet);
	}
}

METHOD(task_manager_t, flush_queue, void,
	private_task_manager_t *this, task_queue_t queue)
{
	array_t *array;
	task_t *task;

	switch (queue)
	{
		case TASK_QUEUE_ACTIVE:
			array = this->active_tasks;
			break;
		case TASK_QUEUE_PASSIVE:
			array = this->passive_tasks;
			break;
		case TASK_QUEUE_QUEUED:
			array = this->queued_tasks;
			break;
		default:
			return;
	}
	while (array_remove(array, ARRAY_TAIL, &task))
	{
		if (queue == TASK_QUEUE_QUEUED)
		{
			queued_task_t *queued = (queued_task_t*)task;
			task = queued->task;
			free(queued);
		}
		task->destroy(task);
	}
}

METHOD(task_manager_t, flush, void,
	private_task_manager_t *this)
{
	flush_queue(this, TASK_QUEUE_QUEUED);
	flush_queue(this, TASK_QUEUE_PASSIVE);
	flush_queue(this, TASK_QUEUE_ACTIVE);
}

/**
 * Check if a given task has been queued already
 */
static bool has_queued(private_task_manager_t *this, task_queue_t queue,
					   task_type_t type)
{
	enumerator_t *enumerator;
	array_t *array;
	task_t *task;
	bool found = FALSE;

	switch (queue)
	{
		case TASK_QUEUE_ACTIVE:
			array = this->active_tasks;
			break;
		case TASK_QUEUE_PASSIVE:
			array = this->passive_tasks;
			break;
		case TASK_QUEUE_QUEUED:
			array = this->queued_tasks;
			break;
		default:
			return FALSE;
	}

	enumerator = array_create_enumerator(array);
	while (enumerator->enumerate(enumerator, &task))
	{
		if (queue == TASK_QUEUE_QUEUED)
		{
			task = ((queued_task_t*)task)->task;
		}
		if (task->get_type(task) == type)
		{
			found = TRUE;
			break;
		}
	}
	enumerator->destroy(enumerator);
	return found;
}

/**
 * Move a task of a specific type from the queue to the active list, if it is
 * not delayed.
 */
static bool activate_task(private_task_manager_t *this, task_type_t type)
{
	enumerator_t *enumerator;
	queued_task_t *queued;
	timeval_t now;
	bool found = FALSE;

	time_monotonic(&now);

	enumerator = array_create_enumerator(this->queued_tasks);
	while (enumerator->enumerate(enumerator, (void**)&queued))
	{
		if (queued->task->get_type(queued->task) == type &&
			!timercmp(&now, &queued->time, <))
		{
			DBG2(DBG_IKE, "  activating %N task", task_type_names, type);
			array_remove_at(this->queued_tasks, enumerator);
			array_insert(this->active_tasks, ARRAY_TAIL, queued->task);
			free(queued);
			found = TRUE;
			break;
		}
	}
	enumerator->destroy(enumerator);
	return found;
}

/**
 * Send packets in the given array (they get cloned). Optionally, the
 * source and destination addresses are changed before sending it.
 */
static void send_packets(private_task_manager_t *this, array_t *packets,
						 host_t *src, host_t *dst)
{
	packet_t *packet, *clone;
	int i;

	for (i = 0; i < array_count(packets); i++)
	{
		array_get(packets, i, &packet);
		clone = packet->clone(packet);
		if (src)
		{
			clone->set_source(clone, src->clone(src));
		}
		if (dst)
		{
			clone->set_destination(clone, dst->clone(dst));
		}
		charon->sender->send(charon->sender, clone);
	}
}

/**
 * Generates the given message and stores packet(s) in the given array
 */
static bool generate_message(private_task_manager_t *this, message_t *message,
							 array_t **packets)
{
	enumerator_t *fragments;
	packet_t *fragment;

	if (this->ike_sa->generate_message_fragmented(this->ike_sa, message,
												  &fragments) != SUCCESS)
	{
		return FALSE;
	}
	while (fragments->enumerate(fragments, &fragment))
	{
		array_insert_create(packets, ARRAY_TAIL, fragment);
	}
	fragments->destroy(fragments);
	array_compress(*packets);
	return TRUE;
}

METHOD(task_manager_t, retransmit, status_t,
	private_task_manager_t *this, uint32_t message_id)
{
	if (message_id == this->initiating.mid &&
		array_count(this->initiating.packets))
	{
		uint32_t timeout;
		job_t *job;
		enumerator_t *enumerator;
		packet_t *packet;
		task_t *task;
		ike_mobike_t *mobike = NULL;

		array_get(this->initiating.packets, 0, &packet);

		/* check if we are retransmitting a MOBIKE routability check */
		if (this->initiating.type == INFORMATIONAL)
		{
			enumerator = array_create_enumerator(this->active_tasks);
			while (enumerator->enumerate(enumerator, (void*)&task))
			{
				if (task->get_type(task) == TASK_IKE_MOBIKE)
				{
					mobike = (ike_mobike_t*)task;
					break;
				}
			}
			enumerator->destroy(enumerator);
		}

		if (!mobike || !mobike->is_probing(mobike))
		{
			if (this->initiating.retransmitted > this->retransmit.tries)
			{
				DBG1(DBG_IKE, "giving up after %d retransmits",
					 this->initiating.retransmitted - 1);
				charon->bus->alert(charon->bus, ALERT_RETRANSMIT_SEND_TIMEOUT,
								   packet);
				return DESTROY_ME;
			}
			timeout = retransmission_timeout(&this->retransmit,
											 this->initiating.retransmitted, TRUE);
			if (this->initiating.retransmitted)
			{
				DBG1(DBG_IKE, "retransmit %d of request with message ID %d",
					 this->initiating.retransmitted, message_id);
				charon->bus->alert(charon->bus, ALERT_RETRANSMIT_SEND, packet,
								   this->initiating.retransmitted);
				this->initiating.retransmit_sent = TRUE;
			}
			if (!mobike)
			{
				send_packets(this, this->initiating.packets,
							 this->ike_sa->get_my_host(this->ike_sa),
							 this->ike_sa->get_other_host(this->ike_sa));
			}
			else
			{
				if (!mobike->transmit(mobike, packet))
				{
					DBG1(DBG_IKE, "no route found to reach peer, MOBIKE update "
						 "deferred");
					this->ike_sa->set_condition(this->ike_sa, COND_STALE, TRUE);
					this->initiating.deferred = TRUE;
					return INVALID_STATE;
				}
				else if (mobike->is_probing(mobike))
				{
					timeout = ROUTABILITY_CHECK_INTERVAL;
				}
			}
		}
		else
		{	/* for routability checks, we use a more aggressive behavior */
			if (this->initiating.retransmitted <= ROUTABILITY_CHECK_TRIES)
			{
				timeout = ROUTABILITY_CHECK_INTERVAL;
			}
			else
			{
				DBG1(DBG_IKE, "giving up after %d path probings",
					 this->initiating.retransmitted - 1);
				return DESTROY_ME;
			}

			if (this->initiating.retransmitted)
			{
				DBG1(DBG_IKE, "path probing attempt %d",
					 this->initiating.retransmitted);
			}
			/* TODO-FRAG: presumably these small packets are not fragmented,
			 * we should maybe ensure this is the case when generating them */
			if (!mobike->transmit(mobike, packet))
			{
				DBG1(DBG_IKE, "no route found to reach peer, path probing "
					 "deferred");
				this->ike_sa->set_condition(this->ike_sa, COND_STALE, TRUE);
				this->initiating.deferred = TRUE;
				return INVALID_STATE;
			}
		}

		this->initiating.retransmitted++;
		job = (job_t*)retransmit_job_create(this->initiating.mid,
											this->ike_sa->get_id(this->ike_sa));
		lib->scheduler->schedule_job_ms(lib->scheduler, job, timeout);
		return SUCCESS;
	}
	return INVALID_STATE;
}

/**
 * Derive IKE keys if necessary
 */
static bool derive_keys(private_task_manager_t *this, array_t *tasks)
{
	enumerator_t *enumerator;
	task_t *task;

	enumerator = array_create_enumerator(tasks);
	while (enumerator->enumerate(enumerator, (void*)&task))
	{
		if (task->get_type(task) == TASK_IKE_INIT)
		{
			ike_init_t *ike_init = (ike_init_t*)task;

			switch (ike_init->derive_keys(ike_init))
			{
				case SUCCESS:
					array_remove_at(tasks, enumerator);
					task->destroy(task);
					break;
				case NEED_MORE:
					break;
				default:
					enumerator->destroy(enumerator);
					return FALSE;
			}
			break;
		}
	}
	enumerator->destroy(enumerator);
	return TRUE;
}

METHOD(task_manager_t, initiate, status_t,
	private_task_manager_t *this)
{
	enumerator_t *enumerator;
	task_t *task;
	message_t *message;
	host_t *me, *other;
	exchange_type_t exchange = 0;
	bool result;

	if (this->initiating.type != EXCHANGE_TYPE_UNDEFINED)
	{
		DBG2(DBG_IKE, "delaying task initiation, %N exchange in progress",
				exchange_type_names, this->initiating.type);
		/* do not initiate if we already have a message in the air */
		if (this->initiating.deferred)
		{	/* re-initiate deferred exchange */
			this->initiating.deferred = FALSE;
			this->initiating.retransmitted = 0;
			return retransmit(this, this->initiating.mid);
		}
		return SUCCESS;
	}

	if (array_count(this->active_tasks) == 0)
	{
		DBG2(DBG_IKE, "activating new tasks");
		switch (this->ike_sa->get_state(this->ike_sa))
		{
			case IKE_CREATED:
				activate_task(this, TASK_IKE_VENDOR);
				if (activate_task(this, TASK_IKE_INIT))
				{
					this->initiating.mid = 0;
					exchange = IKE_SA_INIT;
					activate_task(this, TASK_IKE_NATD);
					activate_task(this, TASK_IKE_CERT_PRE);
					activate_task(this, TASK_IKE_AUTH);
					activate_task(this, TASK_IKE_CERT_POST);
#ifdef ME
					activate_task(this, TASK_IKE_ME);
#endif /* ME */
					activate_task(this, TASK_IKE_CONFIG);
					activate_task(this, TASK_IKE_AUTH_LIFETIME);
					activate_task(this, TASK_IKE_MOBIKE);
					/* make sure this is the last IKE-related task */
					activate_task(this, TASK_IKE_ESTABLISH);
					activate_task(this, TASK_CHILD_CREATE);
				}
				break;
			case IKE_ESTABLISHED:
				if (activate_task(this, TASK_IKE_MOBIKE))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_IKE_DELETE))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_IKE_REDIRECT))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_CHILD_DELETE))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_IKE_REAUTH))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_CHILD_CREATE))
				{
					exchange = CREATE_CHILD_SA;
					break;
				}
				if (activate_task(this, TASK_CHILD_REKEY))
				{
					exchange = CREATE_CHILD_SA;
					break;
				}
				if (activate_task(this, TASK_IKE_REKEY))
				{
					exchange = CREATE_CHILD_SA;
					break;
				}
				if (activate_task(this, TASK_IKE_DPD))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_IKE_AUTH_LIFETIME))
				{
					exchange = INFORMATIONAL;
					break;
				}
#ifdef ME
				if (activate_task(this, TASK_IKE_ME))
				{
					exchange = ME_CONNECT;
					break;
				}
#endif /* ME */
				if (activate_task(this, TASK_IKE_REAUTH_COMPLETE))
				{
					exchange = INFORMATIONAL;
					break;
				}
				if (activate_task(this, TASK_IKE_VERIFY_PEER_CERT))
				{
					exchange = INFORMATIONAL;
					break;
				}
			case IKE_REKEYING:
			case IKE_REKEYED:
				if (activate_task(this, TASK_IKE_DELETE))
				{
					exchange = INFORMATIONAL;
					break;
				}
			case IKE_DELETING:
			default:
				break;
		}
	}
	else
	{
		if (!derive_keys(this, this->active_tasks))
		{
			return DESTROY_ME;
		}

		DBG2(DBG_IKE, "reinitiating already active tasks");
		enumerator = array_create_enumerator(this->active_tasks);
		while (enumerator->enumerate(enumerator, &task))
		{
			DBG2(DBG_IKE, "  %N task", task_type_names, task->get_type(task));
			switch (task->get_type(task))
			{
				case TASK_IKE_INIT:
					exchange = IKE_SA_INIT;
					break;
				case TASK_IKE_AUTH:
					exchange = IKE_AUTH;
					break;
				case TASK_CHILD_CREATE:
				case TASK_CHILD_REKEY:
				case TASK_IKE_REKEY:
					exchange = CREATE_CHILD_SA;
					break;
				case TASK_IKE_MOBIKE:
					exchange = INFORMATIONAL;
					break;
				default:
					continue;
			}
			break;
		}
		enumerator->destroy(enumerator);
	}

	if (exchange == 0)
	{
		DBG2(DBG_IKE, "nothing to initiate");
		/* nothing to do yet... */
		return SUCCESS;
	}

	me = this->ike_sa->get_my_host(this->ike_sa);
	other = this->ike_sa->get_other_host(this->ike_sa);

	message = message_create(IKEV2_MAJOR_VERSION, IKEV2_MINOR_VERSION);
	message->set_message_id(message, this->initiating.mid);
	message->set_source(message, me->clone(me));
	message->set_destination(message, other->clone(other));
	message->set_exchange_type(message, exchange);
	this->initiating.type = exchange;
	this->initiating.retransmitted = 0;
	this->initiating.retransmit_sent = FALSE;
	this->initiating.deferred = FALSE;

	enumerator = array_create_enumerator(this->active_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		switch (task->build(task, message))
		{
			case SUCCESS:
				/* task completed, remove it */
				array_remove_at(this->active_tasks, enumerator);
				task->destroy(task);
				break;
			case NEED_MORE:
				/* processed, but task needs another exchange */
				break;
			case FAILED:
			default:
				this->initiating.type = EXCHANGE_TYPE_UNDEFINED;
				if (this->ike_sa->get_state(this->ike_sa) != IKE_CONNECTING &&
					this->ike_sa->get_state(this->ike_sa) != IKE_REKEYED)
				{
					charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
				}
				/* FALL */
			case DESTROY_ME:
				/* critical failure, destroy IKE_SA */
				enumerator->destroy(enumerator);
				message->destroy(message);
				flush(this);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	/* update exchange type if a task changed it */
	this->initiating.type = message->get_exchange_type(message);
	if (this->initiating.type == EXCHANGE_TYPE_UNDEFINED)
	{
		message->destroy(message);
		return initiate(this);
	}

	result = generate_message(this, message, &this->initiating.packets);

	if (result)
	{
		enumerator = array_create_enumerator(this->active_tasks);
		while (enumerator->enumerate(enumerator, &task))
		{
			if (!task->post_build)
			{
				continue;
			}
			switch (task->post_build(task, message))
			{
				case SUCCESS:
					array_remove_at(this->active_tasks, enumerator);
					task->destroy(task);
					break;
				case NEED_MORE:
					break;
				default:
					/* critical failure, destroy IKE_SA */
					result = FALSE;
					break;
			}
		}
		enumerator->destroy(enumerator);
	}
	message->destroy(message);

	if (!result)
	{	/* message generation failed. There is nothing more to do than to
		 * close the SA */
		flush(this);
		if (this->ike_sa->get_state(this->ike_sa) != IKE_CONNECTING &&
			this->ike_sa->get_state(this->ike_sa) != IKE_REKEYED)
		{
			charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
		}
		return DESTROY_ME;
	}

	array_compress(this->active_tasks);
	array_compress(this->queued_tasks);

	return retransmit(this, this->initiating.mid);
}

/**
 * handle an incoming response message
 */
static status_t process_response(private_task_manager_t *this,
								 message_t *message)
{
	enumerator_t *enumerator;
	task_t *task;

	if (message->get_exchange_type(message) != this->initiating.type)
	{
		DBG1(DBG_IKE, "received %N response, but expected %N",
			 exchange_type_names, message->get_exchange_type(message),
			 exchange_type_names, this->initiating.type);
		charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
		return DESTROY_ME;
	}

	/* handle fatal INVALID_SYNTAX notifies */
	switch (message->get_exchange_type(message))
	{
		case CREATE_CHILD_SA:
		case INFORMATIONAL:
			if (message->get_notify(message, INVALID_SYNTAX))
			{
				DBG1(DBG_IKE, "received %N notify error, destroying IKE_SA",
					 notify_type_names, INVALID_SYNTAX);
				charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
				return DESTROY_ME;
			}
			break;
		default:
			break;
	}

	enumerator = array_create_enumerator(this->active_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		if (!task->pre_process)
		{
			continue;
		}
		switch (task->pre_process(task, message))
		{
			case SUCCESS:
				break;
			case FAILED:
			default:
				/* just ignore the message */
				DBG1(DBG_IKE, "ignore invalid %N response",
					 exchange_type_names, message->get_exchange_type(message));
				enumerator->destroy(enumerator);
				return SUCCESS;
			case DESTROY_ME:
				/* critical failure, destroy IKE_SA */
				enumerator->destroy(enumerator);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	if (this->initiating.retransmit_sent)
	{
		packet_t *packet = NULL;
		array_get(this->initiating.packets, 0, &packet);
		charon->bus->alert(charon->bus, ALERT_RETRANSMIT_SEND_CLEARED, packet);
	}

	/* catch if we get reset while processing */
	this->reset = FALSE;
	enumerator = array_create_enumerator(this->active_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		switch (task->process(task, message))
		{
			case SUCCESS:
				/* task completed, remove it */
				array_remove_at(this->active_tasks, enumerator);
				task->destroy(task);
				break;
			case NEED_MORE:
				/* processed, but task needs another exchange */
				break;
			case FAILED:
			default:
				charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
				/* FALL */
			case DESTROY_ME:
				/* critical failure, destroy IKE_SA */
				array_remove_at(this->active_tasks, enumerator);
				enumerator->destroy(enumerator);
				task->destroy(task);
				return DESTROY_ME;
		}
		if (this->reset)
		{	/* start all over again if we were reset */
			this->reset = FALSE;
			enumerator->destroy(enumerator);
			return initiate(this);
		}
	}
	enumerator->destroy(enumerator);

	enumerator = array_create_enumerator(this->active_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		if (!task->post_process)
		{
			continue;
		}
		switch (task->post_process(task, message))
		{
			case SUCCESS:
				array_remove_at(this->active_tasks, enumerator);
				task->destroy(task);
				break;
			case NEED_MORE:
				break;
			default:
				/* critical failure, destroy IKE_SA */
				array_remove_at(this->active_tasks, enumerator);
				enumerator->destroy(enumerator);
				task->destroy(task);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	this->initiating.mid++;
	this->initiating.type = EXCHANGE_TYPE_UNDEFINED;
	clear_packets(this->initiating.packets);

	array_compress(this->active_tasks);

	return initiate(this);
}

/**
 * Handle exchange collisions, returns TRUE if the given passive task was
 * adopted by the active task and the task manager lost control over it.
 */
static bool handle_collisions(private_task_manager_t *this, task_t *task)
{
	enumerator_t *enumerator;
	task_t *active;
	task_type_t type;
	bool adopted = FALSE;

	type = task->get_type(task);

	/* collisions between a child-rekey and child-delete task are handled
	 * directly by the latter */
	if (type == TASK_IKE_REKEY || type == TASK_IKE_DELETE ||
		type == TASK_CHILD_REKEY)
	{
		/* find an exchange collision, and notify these tasks */
		enumerator = array_create_enumerator(this->active_tasks);
		while (enumerator->enumerate(enumerator, &active))
		{
			switch (active->get_type(active))
			{
				case TASK_IKE_REKEY:
					if (type == TASK_IKE_REKEY || type == TASK_IKE_DELETE)
					{
						ike_rekey_t *rekey = (ike_rekey_t*)active;
						adopted = rekey->collide(rekey, task);
						break;
					}
					continue;
				case TASK_CHILD_REKEY:
					if (type == TASK_CHILD_REKEY)
					{
						child_rekey_t *rekey = (child_rekey_t*)active;
						adopted = rekey->collide(rekey, task);
						break;
					}
					continue;
				default:
					continue;
			}
			enumerator->destroy(enumerator);
			return adopted;
		}
		enumerator->destroy(enumerator);
	}
	return adopted;
}

/**
 * build a response depending on the "passive" task list
 */
static status_t build_response(private_task_manager_t *this, message_t *request)
{
	enumerator_t *enumerator;
	task_t *task;
	message_t *message;
	host_t *me, *other;
	bool delete = FALSE, hook = FALSE, mid_sync = FALSE;
	ike_sa_id_t *id = NULL;
	uint64_t responder_spi = 0;
	bool result;

	me = request->get_destination(request);
	other = request->get_source(request);

	message = message_create(IKEV2_MAJOR_VERSION, IKEV2_MINOR_VERSION);
	message->set_exchange_type(message, request->get_exchange_type(request));
	/* send response along the path the request came in */
	message->set_source(message, me->clone(me));
	message->set_destination(message, other->clone(other));
	message->set_message_id(message, this->responding.mid);
	message->set_request(message, FALSE);

	enumerator = array_create_enumerator(this->passive_tasks);
	while (enumerator->enumerate(enumerator, (void*)&task))
	{
		if (task->get_type(task) == TASK_IKE_MID_SYNC)
		{
			mid_sync = TRUE;
		}
		switch (task->build(task, message))
		{
			case SUCCESS:
				/* task completed, remove it */
				array_remove_at(this->passive_tasks, enumerator);
				if (!handle_collisions(this, task))
				{
					task->destroy(task);
				}
				break;
			case NEED_MORE:
				/* processed, but task needs another exchange */
				if (handle_collisions(this, task))
				{
					array_remove_at(this->passive_tasks, enumerator);
				}
				break;
			case FAILED:
			default:
				hook = TRUE;
				/* FALL */
			case DESTROY_ME:
				/* destroy IKE_SA, but SEND response first */
				if (handle_collisions(this, task))
				{
					array_remove_at(this->passive_tasks, enumerator);
				}
				delete = TRUE;
				break;
		}
		if (delete)
		{
			break;
		}
	}
	enumerator->destroy(enumerator);

	/* RFC 5996, section 2.6 mentions that in the event of a failure during
	 * IKE_SA_INIT the responder's SPI will be 0 in the response, while it
	 * actually explicitly allows it to be non-zero.  Since we use the responder
	 * SPI to create hashes in the IKE_SA manager we can only set the SPI to
	 * zero temporarily, otherwise checking the SA in would fail. */
	if (delete && request->get_exchange_type(request) == IKE_SA_INIT)
	{
		id = this->ike_sa->get_id(this->ike_sa);
		responder_spi = id->get_responder_spi(id);
		id->set_responder_spi(id, 0);
	}

	/* message complete, send it */
	clear_packets(this->responding.packets);
	result = generate_message(this, message, &this->responding.packets);

	if (result && !delete)
	{
		enumerator = array_create_enumerator(this->passive_tasks);
		while (enumerator->enumerate(enumerator, &task))
		{
			if (!task->post_build)
			{
				continue;
			}
			switch (task->post_build(task, message))
			{
				case SUCCESS:
					array_remove_at(this->passive_tasks, enumerator);
					task->destroy(task);
					break;
				case NEED_MORE:
					break;
				default:
					/* critical failure, destroy IKE_SA */
					result = FALSE;
					break;
			}
		}
		enumerator->destroy(enumerator);
	}
	message->destroy(message);

	if (id)
	{
		id->set_responder_spi(id, responder_spi);
	}
	if (!result)
	{
		charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
		return DESTROY_ME;
	}

	send_packets(this, this->responding.packets, NULL, NULL);
	if (delete)
	{
		if (hook)
		{
			charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
		}
		return DESTROY_ME;
	}
	else if (mid_sync)
	{
		/* we don't want to resend messages to sync MIDs if requests with the
		 * previous MID arrive */
		clear_packets(this->responding.packets);
		/* avoid increasing the expected message ID after handling a message
		 * to sync MIDs with MID 0 */
		return NEED_MORE;
	}

	array_compress(this->passive_tasks);

	return SUCCESS;
}

/**
 * handle an incoming request message
 */
static status_t process_request(private_task_manager_t *this,
								message_t *message)
{
	enumerator_t *enumerator;
	task_t *task = NULL;
	payload_t *payload;
	notify_payload_t *notify;
	delete_payload_t *delete;
	ike_sa_state_t state;

	if (array_count(this->passive_tasks) == 0)
	{	/* create tasks depending on request type, if not already some queued */
		state = this->ike_sa->get_state(this->ike_sa);
		switch (message->get_exchange_type(message))
		{
			case IKE_SA_INIT:
			{
				task = (task_t*)ike_vendor_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_init_create(this->ike_sa, FALSE, NULL);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_natd_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_cert_pre_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_auth_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_cert_post_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
#ifdef ME
				task = (task_t*)ike_me_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
#endif /* ME */
				task = (task_t*)ike_config_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)ike_mobike_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				/* this should generally be the last IKE-related task */
				task = (task_t*)ike_establish_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				/* make sure this comes after the above task to send the correct
				 * reauth time, as responder the task doesn't modify it anymore */
				task = (task_t*)ike_auth_lifetime_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				task = (task_t*)child_create_create(this->ike_sa, NULL, FALSE,
													NULL, NULL, 0);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				break;
			}
			case CREATE_CHILD_SA:
			{	/* FIXME: we should prevent this on mediation connections */
				bool notify_found = FALSE, ts_found = FALSE;

				if (state == IKE_CREATED ||
					state == IKE_CONNECTING)
				{
					DBG1(DBG_IKE, "received CREATE_CHILD_SA request for "
						 "unestablished IKE_SA, rejected");
					return FAILED;
				}

				enumerator = message->create_payload_enumerator(message);
				while (enumerator->enumerate(enumerator, &payload))
				{
					switch (payload->get_type(payload))
					{
						case PLV2_NOTIFY:
						{	/* if we find a rekey notify, its CHILD_SA rekeying */
							notify = (notify_payload_t*)payload;
							if (notify->get_notify_type(notify) == REKEY_SA &&
								(notify->get_protocol_id(notify) == PROTO_AH ||
								 notify->get_protocol_id(notify) == PROTO_ESP))
							{
								notify_found = TRUE;
							}
							break;
						}
						case PLV2_TS_INITIATOR:
						case PLV2_TS_RESPONDER:
						{	/* if we don't find a TS, its IKE rekeying */
							ts_found = TRUE;
							break;
						}
						default:
							break;
					}
				}
				enumerator->destroy(enumerator);

				if (ts_found)
				{
					if (notify_found)
					{
						task = (task_t*)child_rekey_create(this->ike_sa,
														   PROTO_NONE, 0);
					}
					else
					{
						task = (task_t*)child_create_create(this->ike_sa, NULL,
															FALSE, NULL, NULL, 0);
					}
				}
				else
				{
					task = (task_t*)ike_rekey_create(this->ike_sa, FALSE);
				}
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				break;
			}
			case INFORMATIONAL:
			{
				enumerator = message->create_payload_enumerator(message);
				while (enumerator->enumerate(enumerator, &payload))
				{
					switch (payload->get_type(payload))
					{
						case PLV2_NOTIFY:
						{
							notify = (notify_payload_t*)payload;
							if (state == IKE_REKEYED)
							{
								DBG1(DBG_IKE, "received unexpected notify %N "
									 "for rekeyed IKE_SA, ignored",
									 notify_type_names,
									 notify->get_notify_type(notify));
								break;
							}
							switch (notify->get_notify_type(notify))
							{
								case ADDITIONAL_IP4_ADDRESS:
								case ADDITIONAL_IP6_ADDRESS:
								case NO_ADDITIONAL_ADDRESSES:
								case UPDATE_SA_ADDRESSES:
								case NO_NATS_ALLOWED:
								case UNACCEPTABLE_ADDRESSES:
								case UNEXPECTED_NAT_DETECTED:
								case COOKIE2:
								case NAT_DETECTION_SOURCE_IP:
								case NAT_DETECTION_DESTINATION_IP:
									task = (task_t*)ike_mobike_create(
															this->ike_sa, FALSE);
									break;
								case AUTH_LIFETIME:
									task = (task_t*)ike_auth_lifetime_create(
															this->ike_sa, FALSE);
									break;
								case INVALID_SYNTAX:
								case AUTHENTICATION_FAILED:
									/* initiator failed to authenticate us or
									 * parse our response. we use ike_delete to
									 * handle this, which invokes all the
									 * required hooks */
									task = (task_t*)ike_delete_create(
														this->ike_sa, FALSE);
									break;
								case REDIRECT:
									task = (task_t*)ike_redirect_create(
															this->ike_sa, NULL);
									break;
								case IKEV2_MESSAGE_ID_SYNC:
									task = (task_t*)ike_mid_sync_create(
																 this->ike_sa);
									break;
								default:
									break;
							}
							break;
						}
						case PLV2_DELETE:
						{
							delete = (delete_payload_t*)payload;
							if (delete->get_protocol_id(delete) == PROTO_IKE)
							{
								task = (task_t*)ike_delete_create(this->ike_sa,
																FALSE);
							}
							else
							{
								task = (task_t*)child_delete_create(this->ike_sa,
														PROTO_NONE, 0, FALSE);
							}
							break;
						}
						default:
							break;
					}
					if (task)
					{
						break;
					}
				}
				enumerator->destroy(enumerator);

				if (task == NULL)
				{
					task = (task_t*)ike_dpd_create(FALSE);
				}
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
				break;
			}
#ifdef ME
			case ME_CONNECT:
			{
				task = (task_t*)ike_me_create(this->ike_sa, FALSE);
				array_insert(this->passive_tasks, ARRAY_TAIL, task);
			}
#endif /* ME */
			default:
				break;
		}
	}

	enumerator = array_create_enumerator(this->passive_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		if (!task->pre_process)
		{
			continue;
		}
		switch (task->pre_process(task, message))
		{
			case SUCCESS:
				break;
			case FAILED:
			default:
				/* just ignore the message */
				DBG1(DBG_IKE, "ignore invalid %N request",
					 exchange_type_names, message->get_exchange_type(message));
				enumerator->destroy(enumerator);
				switch (message->get_exchange_type(message))
				{
					case IKE_SA_INIT:
						/* no point in keeping the SA when it was created with
						 * an invalid IKE_SA_INIT message */
						return DESTROY_ME;
					default:
						/* remove tasks we queued for this request */
						flush_queue(this, TASK_QUEUE_PASSIVE);
						/* fall-through */
					case IKE_AUTH:
						return NEED_MORE;
				}
			case DESTROY_ME:
				/* critical failure, destroy IKE_SA */
				enumerator->destroy(enumerator);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	/* let the tasks process the message */
	enumerator = array_create_enumerator(this->passive_tasks);
	while (enumerator->enumerate(enumerator, (void*)&task))
	{
		switch (task->process(task, message))
		{
			case SUCCESS:
				/* task completed, remove it */
				array_remove_at(this->passive_tasks, enumerator);
				task->destroy(task);
				break;
			case NEED_MORE:
				/* processed, but task needs at least another call to build() */
				break;
			case FAILED:
			default:
				charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
				/* FALL */
			case DESTROY_ME:
				/* critical failure, destroy IKE_SA */
				array_remove_at(this->passive_tasks, enumerator);
				enumerator->destroy(enumerator);
				task->destroy(task);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	enumerator = array_create_enumerator(this->passive_tasks);
	while (enumerator->enumerate(enumerator, &task))
	{
		if (!task->post_process)
		{
			continue;
		}
		switch (task->post_process(task, message))
		{
			case SUCCESS:
				array_remove_at(this->passive_tasks, enumerator);
				task->destroy(task);
				break;
			case NEED_MORE:
				break;
			default:
				/* critical failure, destroy IKE_SA */
				array_remove_at(this->passive_tasks, enumerator);
				enumerator->destroy(enumerator);
				task->destroy(task);
				return DESTROY_ME;
		}
	}
	enumerator->destroy(enumerator);

	return build_response(this, message);
}

METHOD(task_manager_t, incr_mid, void,
	private_task_manager_t *this, bool initiate)
{
	if (initiate)
	{
		this->initiating.mid++;
	}
	else
	{
		this->responding.mid++;
	}
}

METHOD(task_manager_t, get_mid, uint32_t,
	private_task_manager_t *this, bool initiate)
{
	return initiate ? this->initiating.mid : this->responding.mid;
}

/**
 * Hash the given message with SHA-1
 */
static bool hash_message(message_t *msg, uint8_t hash[HASH_SIZE_SHA1])
{
	hasher_t *hasher;

	hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
	if (!hasher ||
		!hasher->get_hash(hasher, msg->get_packet_data(msg), hash))
	{
		DESTROY_IF(hasher);
		return FALSE;
	}
	hasher->destroy(hasher);
	return TRUE;
}

/**
 * Handle the given IKE fragment, if it is one.
 *
 * Returns SUCCESS if the message is not a fragment, and NEED_MORE if it was
 * handled properly.  Error states are returned if the fragment was invalid or
 * the reassembled message could not be processed properly.
 */
static status_t handle_fragment(private_task_manager_t *this,
								message_t **defrag, message_t *msg)
{
	encrypted_fragment_payload_t *fragment;
	status_t status;

	fragment = (encrypted_fragment_payload_t*)msg->get_payload(msg,
															   PLV2_FRAGMENT);
	if (!fragment)
	{
		/* ignore reassembled messages, we collected their fragments below */
		if (msg != *defrag)
		{
			hash_message(msg, this->responding.hash);
		}
		return SUCCESS;
	}
	if (!*defrag)
	{
		*defrag = message_create_defrag(msg);
		if (!*defrag)
		{
			return FAILED;
		}
	}
	status = (*defrag)->add_fragment(*defrag, msg);

	if (status == NEED_MORE || status == SUCCESS)
	{
		/* to detect retransmissions we only hash the first fragment */
		if (fragment->get_fragment_number(fragment) == 1)
		{
			hash_message(msg, this->responding.hash);
		}
	}
	if (status == SUCCESS)
	{
		/* reinject the reassembled message */
		status = this->ike_sa->process_message(this->ike_sa, *defrag);
		if (status == SUCCESS)
		{
			/* avoid processing the last fragment */
			status = NEED_MORE;
		}
		(*defrag)->destroy(*defrag);
		*defrag = NULL;
	}
	return status;
}

/**
 * Send a notify back to the sender
 */
static void send_notify_response(private_task_manager_t *this,
								 message_t *request, notify_type_t type,
								 chunk_t data)
{
	message_t *response;
	packet_t *packet;
	host_t *me, *other;

	response = message_create(IKEV2_MAJOR_VERSION, IKEV2_MINOR_VERSION);
	response->set_exchange_type(response, request->get_exchange_type(request));
	response->set_request(response, FALSE);
	response->set_message_id(response, request->get_message_id(request));
	response->add_notify(response, FALSE, type, data);
	me = this->ike_sa->get_my_host(this->ike_sa);
	if (me->is_anyaddr(me))
	{
		me = request->get_destination(request);
		this->ike_sa->set_my_host(this->ike_sa, me->clone(me));
	}
	other = this->ike_sa->get_other_host(this->ike_sa);
	if (other->is_anyaddr(other))
	{
		other = request->get_source(request);
		this->ike_sa->set_other_host(this->ike_sa, other->clone(other));
	}
	response->set_source(response, me->clone(me));
	response->set_destination(response, other->clone(other));
	if (this->ike_sa->generate_message(this->ike_sa, response,
									   &packet) == SUCCESS)
	{
		charon->sender->send(charon->sender, packet);
	}
	response->destroy(response);
}

/**
 * Send an INVALID_SYNTAX notify and destroy the IKE_SA for authenticated
 * messages.
 */
static status_t send_invalid_syntax(private_task_manager_t *this,
									message_t *msg)
{
	send_notify_response(this, msg, INVALID_SYNTAX, chunk_empty);
	incr_mid(this, FALSE);

	/* IKE_SA_INIT is currently the only type the parser accepts unprotected,
	 * don't destroy the IKE_SA if such a message is invalid */
	if (msg->get_exchange_type(msg) == IKE_SA_INIT)
	{
		return FAILED;
	}
	return DESTROY_ME;
}

/**
 * Check for unsupported critical payloads
 */
static status_t has_unsupported_critical_payload(message_t *msg, uint8_t *type)
{
	enumerator_t *enumerator;
	unknown_payload_t *unknown;
	payload_t *payload;
	status_t status = SUCCESS;

	enumerator = msg->create_payload_enumerator(msg);
	while (enumerator->enumerate(enumerator, &payload))
	{
		if (payload->get_type(payload) == PL_UNKNOWN)
		{
			unknown = (unknown_payload_t*)payload;
			if (unknown->is_critical(unknown))
			{
				*type = unknown->get_type(unknown);
				DBG1(DBG_ENC, "payload type %N is not supported, "
					 "but payload is critical!", payload_type_names, *type);
				status = NOT_SUPPORTED;
				break;
			}
		}
	}
	enumerator->destroy(enumerator);
	return status;
}

/**
 * Parse the given message and verify that it is valid.
 */
static status_t parse_message(private_task_manager_t *this, message_t *msg)
{
	status_t parse_status, status;
	uint8_t type = 0;

	if (derive_keys(this, this->passive_tasks))
	{
		parse_status = msg->parse_body(msg, this->ike_sa->get_keymat(this->ike_sa));

		if (parse_status == SUCCESS)
		{
			parse_status = has_unsupported_critical_payload(msg, &type);
		}

		status = parse_status;
	}
	else
	{	/* there is no point in trying again */
		parse_status = INVALID_STATE;
		status = DESTROY_ME;
	}

	if (parse_status != SUCCESS)
	{
		bool is_request = msg->get_request(msg);

		switch (parse_status)
		{
			case NOT_SUPPORTED:
				DBG1(DBG_IKE, "critical unknown payloads found");
				if (is_request)
				{
					send_notify_response(this, msg,
										 UNSUPPORTED_CRITICAL_PAYLOAD,
										 chunk_from_thing(type));
					incr_mid(this, FALSE);
				}
				break;
			case PARSE_ERROR:
				DBG1(DBG_IKE, "message parsing failed");
				if (is_request)
				{
					status = send_invalid_syntax(this, msg);
				}
				break;
			case VERIFY_ERROR:
				DBG1(DBG_IKE, "message verification failed");
				if (is_request)
				{
					status = send_invalid_syntax(this, msg);
				}
				break;
			case FAILED:
				DBG1(DBG_IKE, "integrity check failed");
				/* ignored */
				break;
			case INVALID_STATE:
				DBG1(DBG_IKE, "found encrypted message, but no keys available");
			default:
				break;
		}
		DBG1(DBG_IKE, "%N %s with message ID %d processing failed",
			 exchange_type_names, msg->get_exchange_type(msg),
			 is_request ? "request" : "response",
			 msg->get_message_id(msg));

		charon->bus->alert(charon->bus, ALERT_PARSE_ERROR_BODY, msg,
						   parse_status);

		switch (this->ike_sa->get_state(this->ike_sa))
		{
			case IKE_CREATED:
				/* invalid initiation attempt, close SA */
				status = DESTROY_ME;
				break;
			case IKE_CONNECTING:
			case IKE_REKEYED:
				/* don't trigger updown event in these states */
				break;
			default:
				if (status == DESTROY_ME)
				{
					charon->bus->ike_updown(charon->bus, this->ike_sa, FALSE);
				}
				break;
		}
	}
	return status;
}

/**
 * Check whether we should reject the given request message
 */
static inline bool reject_request(private_task_manager_t *this,
								  message_t *msg)
{
	ike_sa_state_t state;
	exchange_type_t type;
	ike_sa_id_t *ike_sa_id;
	bool reject = FALSE;

	state = this->ike_sa->get_state(this->ike_sa);
	type = msg->get_exchange_type(msg);

	/* reject initial messages if not received in specific states */
	switch (type)
	{
		case IKE_SA_INIT:
			reject = state != IKE_CREATED;
			break;
		case IKE_INTERMEDIATE:
			/* only accept this if we have not yet completed the KEs */
			reject = state != IKE_CONNECTING ||
					 !has_queued(this, TASK_QUEUE_PASSIVE, TASK_IKE_INIT);
			break;
		case IKE_AUTH:
			reject = state != IKE_CONNECTING;
			break;
		default:
			break;
	}

	if (!reject)
	{
		switch (state)
		{
			/* after rekeying we only expect a DELETE in an INFORMATIONAL */
			case IKE_REKEYED:
				reject = type != INFORMATIONAL;
				break;
			/* also reject requests for half-open IKE_SAs as initiator */
			case IKE_CREATED:
			case IKE_CONNECTING:
				ike_sa_id = this->ike_sa->get_id(this->ike_sa);
				reject = ike_sa_id->is_initiator(ike_sa_id);
				break;
			default:
				break;
		}
	}

	if (reject)
	{
		DBG1(DBG_IKE, "ignoring %N in IKE_SA state %N", exchange_type_names,
			 type, ike_sa_state_names, state);
	}
	return reject;
}

/**
 * Check if a message with message ID 0 looks like it is used to synchronize
 * the message IDs.
 *
 * Call this after checking the message with is_potential_mid_sync() first.
 */
static bool is_mid_sync(private_task_manager_t *this, message_t *msg)
{
	enumerator_t *enumerator;
	notify_payload_t *notify;
	payload_t *payload;
	bool found = FALSE, other = FALSE;

	enumerator = msg->create_payload_enumerator(msg);
	while (enumerator->enumerate(enumerator, &payload))
	{
		if (payload->get_type(payload) == PLV2_NOTIFY)
		{
			notify = (notify_payload_t*)payload;
			switch (notify->get_notify_type(notify))
			{
				case IKEV2_MESSAGE_ID_SYNC:
				case IPSEC_REPLAY_COUNTER_SYNC:
					found = TRUE;
					continue;
				default:
					break;
			}
		}
		other = TRUE;
		break;
	}
	enumerator->destroy(enumerator);
	return found && !other;
}

/**
 * Check if a message with message ID 0 looks like it could potentially be used
 * to synchronize the message IDs and if we are prepared to process it.
 *
 * This may be called before the message body is parsed.
 */
static bool is_potential_mid_sync(private_task_manager_t *this, message_t *msg)
{
	return msg->get_exchange_type(msg) == INFORMATIONAL &&
		   this->ike_sa->get_state(this->ike_sa) == IKE_ESTABLISHED &&
		   this->ike_sa->supports_extension(this->ike_sa,
											EXT_IKE_MESSAGE_ID_SYNC);
}

/**
 * Check if the given message is a retransmitted request
 */
static status_t is_retransmit(private_task_manager_t *this, message_t *msg)
{
	uint8_t hash[HASH_SIZE_SHA1];
	uint32_t mid;

	mid = msg->get_message_id(msg);

	if (mid == this->responding.mid)
	{
		return NEED_MORE;
	}

	if (mid == this->responding.mid - 1 &&
		array_count(this->responding.packets))
	{
		if (!hash_message(msg, hash))
		{
			DBG1(DBG_IKE, "failed to hash message, ignored");
			return FAILED;
		}
		if (memeq_const(hash, this->responding.prev_hash, sizeof(hash)))
		{
			return ALREADY_DONE;
		}
	}
	/* this includes fragments with fragment number > 1 (we only hash the first
	 * fragment), for which RFC 7383, section 2.6.1 explicitly does not allow
	 * retransmitting responses. we don't parse/verify these messages to check,
	 * we just ignore them. also included are MID sync messages with MID 0 */
	return INVALID_ARG;
}

METHOD(task_manager_t, process_message, status_t,
	private_task_manager_t *this, message_t *msg)
{
	host_t *me, *other;
	status_t status;
	uint32_t mid, *expected_mid = NULL;
	bool schedule_delete_job = FALSE;

	me = msg->get_destination(msg);
	other = msg->get_source(msg);
	mid = msg->get_message_id(msg);

	charon->bus->message(charon->bus, msg, TRUE, FALSE);

	if (msg->get_request(msg))
	{
		bool potential_mid_sync = FALSE;

		switch (is_retransmit(this, msg))
		{
			case ALREADY_DONE:
				DBG1(DBG_IKE, "received retransmit of request with ID %d, "
					 "retransmitting response", mid);
				this->ike_sa->set_statistic(this->ike_sa, STAT_INBOUND,
											time_monotonic(NULL));
				charon->bus->alert(charon->bus, ALERT_RETRANSMIT_RECEIVE, msg);
				send_packets(this, this->responding.packets,
							 msg->get_destination(msg), msg->get_source(msg));
				return SUCCESS;
			case INVALID_ARG:
				if (mid == 0 && is_potential_mid_sync(this, msg))
				{
					potential_mid_sync = TRUE;
				}
				else
				{
					expected_mid = &this->responding.mid;
					break;
				}
				/* check if it's actually an MID sync message */
			case NEED_MORE:
				status = parse_message(this, msg);
				if (potential_mid_sync && status == SUCCESS &&
					!is_mid_sync(this, msg))
				{
					expected_mid = &this->responding.mid;
				}
				break;
			case FAILED:
			default:
				return FAILED;
		}
	}
	else
	{
		if (mid == this->initiating.mid)
		{
			status = parse_message(this, msg);
		}
		else
		{
			expected_mid = &this->initiating.mid;
		}
	}

	if (expected_mid)
	{
		DBG1(DBG_IKE, "received message ID %d, expected %d, ignored",
			 mid, *expected_mid);
		return SUCCESS;
	}
	else if (status != SUCCESS)
	{
		return status;
	}

	/* if this IKE_SA is virgin, we check for a config */
	if (!this->ike_sa->get_ike_cfg(this->ike_sa))
	{
		ike_cfg_t *ike_cfg;

		ike_cfg = charon->backends->get_ike_cfg(charon->backends,
												me, other, IKEV2);
		if (!ike_cfg)
		{
			/* no config found for these hosts, destroy */
			DBG1(DBG_IKE, "no IKE config found for %H...%H, sending %N",
				 me, other, notify_type_names, NO_PROPOSAL_CHOSEN);
			send_notify_response(this, msg,
								 NO_PROPOSAL_CHOSEN, chunk_empty);
			return DESTROY_ME;
		}
		this->ike_sa->set_ike_cfg(this->ike_sa, ike_cfg);
		ike_cfg->destroy(ike_cfg);
		/* add a timeout if peer does not establish it completely */
		schedule_delete_job = TRUE;
	}

	if (msg->get_request(msg))
	{
		/* special handling for requests happens in is_retransmit()
		 * reject initial messages if not received in specific states,
		 * after rekeying we only expect a DELETE in an INFORMATIONAL */
		if (reject_request(this, msg))
		{
			return FAILED;
		}
		if (!this->ike_sa->supports_extension(this->ike_sa, EXT_MOBIKE))
		{	/* only do implicit updates without MOBIKE, and only force
			 * updates for IKE_AUTH (ports might change due to NAT-T) */
			this->ike_sa->update_hosts(this->ike_sa, me, other,
									   mid == 1 ? UPDATE_HOSTS_FORCE_ADDRS : 0);
		}
		status = handle_fragment(this, &this->responding.defrag, msg);
		if (status != SUCCESS)
		{
			if (status == NEED_MORE)
			{
				this->ike_sa->set_statistic(this->ike_sa, STAT_INBOUND,
											time_monotonic(NULL));
			}
			return status;
		}
		charon->bus->message(charon->bus, msg, TRUE, TRUE);
		if (msg->get_exchange_type(msg) == EXCHANGE_TYPE_UNDEFINED)
		{	/* ignore messages altered to EXCHANGE_TYPE_UNDEFINED */
			return SUCCESS;
		}
		switch (process_request(this, msg))
		{
			case SUCCESS:
				this->ike_sa->set_statistic(this->ike_sa, STAT_INBOUND,
											time_monotonic(NULL));
				this->responding.mid++;
				memcpy(this->responding.prev_hash, this->responding.hash,
					   sizeof(this->responding.prev_hash));
				break;
			case NEED_MORE:
				break;
			default:
				flush(this);
				return DESTROY_ME;
		}
	}
	else
	{
		if (this->ike_sa->get_state(this->ike_sa) == IKE_CREATED ||
			this->ike_sa->get_state(this->ike_sa) == IKE_CONNECTING ||
			msg->get_exchange_type(msg) != IKE_SA_INIT)
		{	/* only do updates based on verified messages (or initial ones) */
			if (!this->ike_sa->supports_extension(this->ike_sa, EXT_MOBIKE))
			{	/* only do implicit updates without MOBIKE, we force an
				 * update of the local address on IKE_SA_INIT as we might
				 * not know it yet, but never for the remote address */
				this->ike_sa->update_hosts(this->ike_sa, me, other,
										   mid == 0 ? UPDATE_HOSTS_FORCE_LOCAL : 0);
			}
		}
		status = handle_fragment(this, &this->initiating.defrag, msg);
		if (status != SUCCESS)
		{
			if (status == NEED_MORE)
			{
				this->ike_sa->set_statistic(this->ike_sa, STAT_INBOUND,
											time_monotonic(NULL));
			}
			return status;
		}
		charon->bus->message(charon->bus, msg, TRUE, TRUE);
		if (msg->get_exchange_type(msg) == EXCHANGE_TYPE_UNDEFINED)
		{	/* ignore messages altered to EXCHANGE_TYPE_UNDEFINED */
			return SUCCESS;
		}
		if (process_response(this, msg) != SUCCESS)
		{
			flush(this);
			return DESTROY_ME;
		}
		this->ike_sa->set_statistic(this->ike_sa, STAT_INBOUND,
									time_monotonic(NULL));
	}

	if (schedule_delete_job)
	{
		ike_sa_id_t *ike_sa_id;
		job_t *job;

		ike_sa_id = this->ike_sa->get_id(this->ike_sa);
		job = (job_t*)delete_ike_sa_job_create(ike_sa_id, FALSE);
		lib->scheduler->schedule_job(lib->scheduler, job,
				lib->settings->get_int(lib->settings,
						"%s.half_open_timeout", HALF_OPEN_IKE_SA_TIMEOUT,
						lib->ns));
	}
	return SUCCESS;
}

METHOD(task_manager_t, queue_task_delayed, void,
	private_task_manager_t *this, task_t *task, uint32_t delay)
{
	queued_task_t *queued;
	timeval_t time;

	time_monotonic(&time);
	if (delay)
	{
		job_t *job;

		DBG2(DBG_IKE, "queueing %N task (delayed by %us)", task_type_names,
			 task->get_type(task), delay);
		time.tv_sec += delay;

		job = (job_t*)initiate_tasks_job_create(
											this->ike_sa->get_id(this->ike_sa));
		lib->scheduler->schedule_job_tv(lib->scheduler, job, time);
	}
	else
	{
		DBG2(DBG_IKE, "queueing %N task", task_type_names,
			 task->get_type(task));
	}
	INIT(queued,
		.task = task,
		.time = time,
	);
	array_insert(this->queued_tasks, ARRAY_TAIL, queued);
}

METHOD(task_manager_t, queue_task, void,
	private_task_manager_t *this, task_t *task)
{
	queue_task_delayed(this, task, 0);
}

METHOD(task_manager_t, queue_ike, void,
	private_task_manager_t *this)
{
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_VENDOR))
	{
		queue_task(this, (task_t*)ike_vendor_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_INIT))
	{
		queue_task(this, (task_t*)ike_init_create(this->ike_sa, TRUE, NULL));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_NATD))
	{
		queue_task(this, (task_t*)ike_natd_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_CERT_PRE))
	{
		queue_task(this, (task_t*)ike_cert_pre_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_AUTH))
	{
		queue_task(this, (task_t*)ike_auth_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_CERT_POST))
	{
		queue_task(this, (task_t*)ike_cert_post_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_CONFIG))
	{
		queue_task(this, (task_t*)ike_config_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_AUTH_LIFETIME))
	{
		queue_task(this, (task_t*)ike_auth_lifetime_create(this->ike_sa, TRUE));
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_MOBIKE))
	{
		peer_cfg_t *peer_cfg;

		peer_cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
		if (!peer_cfg->has_option(peer_cfg, OPT_NO_MOBIKE))
		{
			queue_task(this, (task_t*)ike_mobike_create(this->ike_sa, TRUE));
		}
	}
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_ESTABLISH))
	{
		queue_task(this, (task_t*)ike_establish_create(this->ike_sa, TRUE));
	}
#ifdef ME
	if (!has_queued(this, TASK_QUEUE_QUEUED, TASK_IKE_ME))
	{
		queue_task(this, (task_t*)ike_me_create(this->ike_sa, TRUE));
	}
#endif /* ME */
}

METHOD(task_manager_t, queue_ike_rekey, void,
	private_task_manager_t *this)
{
	queue_task(this, (task_t*)ike_rekey_create(this->ike_sa, TRUE));
}

/**
 * Start reauthentication using make-before-break
 */
static void trigger_mbb_reauth(private_task_manager_t *this)
{
	enumerator_t *enumerator;
	child_sa_t *child_sa;
	child_cfg_t *cfg;
	peer_cfg_t *peer;
	ike_sa_t *new;
	host_t *host;
	queued_task_t *queued;
	uint32_t reqid;
	bool children = FALSE;

	new = charon->ike_sa_manager->create_new(charon->ike_sa_manager,
								this->ike_sa->get_version(this->ike_sa), TRUE);
	if (!new)
	{	/* shouldn't happen */
		return;
	}

	peer = this->ike_sa->get_peer_cfg(this->ike_sa);
	new->set_peer_cfg(new, peer);
	host = this->ike_sa->get_other_host(this->ike_sa);
	new->set_other_host(new, host->clone(host));
	host = this->ike_sa->get_my_host(this->ike_sa);
	new->set_my_host(new, host->clone(host));
	charon->bus->ike_reestablish_pre(charon->bus, this->ike_sa, new);
	enumerator = this->ike_sa->create_virtual_ip_enumerator(this->ike_sa, TRUE);
	while (enumerator->enumerate(enumerator, &host))
	{
		new->add_virtual_ip(new, TRUE, host);
	}
	enumerator->destroy(enumerator);

	enumerator = this->ike_sa->create_child_sa_enumerator(this->ike_sa);
	while (enumerator->enumerate(enumerator, &child_sa))
	{
		child_create_t *child_create;

		switch (child_sa->get_state(child_sa))
		{
			case CHILD_REKEYED:
			case CHILD_DELETED:
				/* ignore CHILD_SAs in these states */
				continue;
			default:
				break;
		}
		cfg = child_sa->get_config(child_sa);
		child_create = child_create_create(new, cfg->get_ref(cfg),
										   FALSE, NULL, NULL, 0);
		child_create->recreate_sa(child_create, child_sa);
		reqid = child_sa->get_reqid_ref(child_sa);
		if (reqid)
		{
			child_create->use_reqid(child_create, reqid);
			charon->kernel->release_reqid(charon->kernel, reqid);
		}
		child_create->use_marks(child_create,
								child_sa->get_mark(child_sa, TRUE).value,
								child_sa->get_mark(child_sa, FALSE).value);
		child_create->use_label(child_create, child_sa->get_label(child_sa));
		child_create->use_per_cpu(child_create, child_sa->use_per_cpu(child_sa),
								  child_sa->get_cpu(child_sa));
		/* interface IDs are not migrated as the new CHILD_SAs on old and new
		 * IKE_SA go though regular updown events */
		new->queue_task(new, &child_create->task);
		children = TRUE;
	}
	enumerator->destroy(enumerator);

	enumerator = array_create_enumerator(this->queued_tasks);
	while (enumerator->enumerate(enumerator, &queued))
	{
		if (queued->task->get_type(queued->task) == TASK_CHILD_CREATE)
		{
			queued->task->migrate(queued->task, new);
			new->queue_task(new, queued->task);
			array_remove_at(this->queued_tasks, enumerator);
			free(queued);
			children = TRUE;
		}
	}
	enumerator->destroy(enumerator);

	if (!children
#ifdef ME
		/* allow reauth of mediation connections without CHILD_SAs */
		&& !peer->is_mediation(peer)
#endif /* ME */
		)
	{
		charon->bus->ike_reestablish_post(charon->bus, this->ike_sa, new,
										  FALSE);
		charon->ike_sa_manager->checkin_and_destroy(charon->ike_sa_manager, new);
		DBG1(DBG_IKE, "unable to reauthenticate IKE_SA, no CHILD_SA "
			 "to recreate");
		return;
	}

	/* suspend online revocation checking until the SA is established */
	new->set_condition(new, COND_ONLINE_VALIDATION_SUSPENDED, TRUE);

	if (new->initiate(new, NULL, NULL) != DESTROY_ME)
	{
		new->queue_task(new, (task_t*)ike_verify_peer_cert_create(new));
		new->queue_task(new, (task_t*)ike_reauth_complete_create(new,
										this->ike_sa->get_id(this->ike_sa)));
		charon->bus->ike_reestablish_post(charon->bus, this->ike_sa, new,
										  TRUE);
		charon->ike_sa_manager->checkin(charon->ike_sa_manager, new);
	}
	else
	{
		charon->bus->ike_reestablish_post(charon->bus, this->ike_sa, new,
										  FALSE);
		charon->ike_sa_manager->checkin_and_destroy(charon->ike_sa_manager, new);
		DBG1(DBG_IKE, "reauthenticating IKE_SA failed");
	}
	charon->bus->set_sa(charon->bus, this->ike_sa);
}

METHOD(task_manager_t, queue_ike_reauth, void,
	private_task_manager_t *this)
{
	if (this->make_before_break)
	{
		return trigger_mbb_reauth(this);
	}
	queue_task(this, (task_t*)ike_reauth_create(this->ike_sa));
}

METHOD(task_manager_t, queue_ike_delete, void,
	private_task_manager_t *this)
{
	queue_task(this, (task_t*)ike_delete_create(this->ike_sa, TRUE));
}

/**
 * There is no need to queue more than one mobike task, so this either returns
 * an already queued task or queues one if there is none yet.
 */
static ike_mobike_t *queue_mobike_task(private_task_manager_t *this)
{
	enumerator_t *enumerator;
	queued_task_t *queued;
	ike_mobike_t *mobike = NULL;

	enumerator = array_create_enumerator(this->queued_tasks);
	while (enumerator->enumerate(enumerator, &queued))
	{
		if (queued->task->get_type(queued->task) == TASK_IKE_MOBIKE)
		{
			mobike = (ike_mobike_t*)queued->task;
			break;
		}
	}
	enumerator->destroy(enumerator);

	if (!mobike)
	{
		mobike = ike_mobike_create(this->ike_sa, TRUE);
		queue_task(this, &mobike->task);
	}
	return mobike;
}

METHOD(task_manager_t, queue_mobike, void,
	private_task_manager_t *this, bool roam, bool address)
{
	ike_mobike_t *mobike;

	mobike = queue_mobike_task(this);
	if (roam)
	{
		enumerator_t *enumerator;
		task_t *current;

		mobike->roam(mobike, address);

		/* enable path probing for a currently active MOBIKE task.  This might
		 * not be the case if an address appeared on a new interface while the
		 * current address is not working but has not yet disappeared. */
		enumerator = array_create_enumerator(this->active_tasks);
		while (enumerator->enumerate(enumerator, &current))
		{
			if (current->get_type(current) == TASK_IKE_MOBIKE)
			{
				ike_mobike_t *active = (ike_mobike_t*)current;
				active->enable_probing(active);
				break;
			}
		}
		enumerator->destroy(enumerator);
	}
	else
	{
		mobike->addresses(mobike);
	}
}

METHOD(task_manager_t, queue_dpd, void,
	private_task_manager_t *this)
{
	ike_mobike_t *mobike;

	if (this->ike_sa->supports_extension(this->ike_sa, EXT_MOBIKE))
	{
#ifdef ME
		peer_cfg_t *cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
		if (cfg->get_peer_id(cfg) ||
			this->ike_sa->has_condition(this->ike_sa, COND_ORIGINAL_INITIATOR))
#else
		if (this->ike_sa->has_condition(this->ike_sa, COND_ORIGINAL_INITIATOR))
#endif
		{
			/* use mobike enabled DPD to detect NAT mapping changes */
			mobike = queue_mobike_task(this);
			mobike->dpd(mobike);
			return;
		}
	}
	queue_task(this, (task_t*)ike_dpd_create(TRUE));
}

METHOD(task_manager_t, queue_child, void,
	private_task_manager_t *this, child_cfg_t *cfg, child_init_args_t *args,
	child_sa_t *child_sa)
{
	child_create_t *task;
	uint32_t reqid;

	if (child_sa)
	{
		task = child_create_create(this->ike_sa, cfg, FALSE, NULL, NULL, 0);
		task->recreate_sa(task, child_sa);
		reqid = child_sa->get_reqid_ref(child_sa);
		if (reqid)
		{
			task->use_reqid(task, reqid);
			charon->kernel->release_reqid(charon->kernel, reqid);
		}
		task->use_label(task, child_sa->get_label(child_sa));
		task->use_per_cpu(task, child_sa->use_per_cpu(child_sa),
						  child_sa->get_cpu(child_sa));
	}
	else if (args)
	{
		task = child_create_create(this->ike_sa, cfg, FALSE, args->src,
								   args->dst, args->seq);
		task->use_reqid(task, args->reqid);
		task->use_label(task, args->label);
		task->use_per_cpu(task, FALSE, args->cpu);
	}
	else
	{
		task = child_create_create(this->ike_sa, cfg, FALSE, NULL, NULL, 0);
	}
	queue_task(this, &task->task);
}

METHOD(task_manager_t, queue_child_rekey, void,
	private_task_manager_t *this, protocol_id_t protocol, uint32_t spi)
{
	queue_task(this, (task_t*)child_rekey_create(this->ike_sa, protocol, spi));
}

METHOD(task_manager_t, queue_child_delete, void,
	private_task_manager_t *this, protocol_id_t protocol, uint32_t spi,
	bool expired)
{
	queue_task(this, (task_t*)child_delete_create(this->ike_sa,
												  protocol, spi, expired));
}

METHOD(task_manager_t, adopt_tasks, void,
	private_task_manager_t *this, task_manager_t *other_public)
{
	private_task_manager_t *other = (private_task_manager_t*)other_public;
	queued_task_t *queued;
	timeval_t now;

	time_monotonic(&now);

	/* move queued tasks from other to this */
	while (array_remove(other->queued_tasks, ARRAY_TAIL, &queued))
	{
		DBG2(DBG_IKE, "migrating %N task", task_type_names,
			 queued->task->get_type(queued->task));
		queued->task->migrate(queued->task, this->ike_sa);
		/* don't delay tasks on the new IKE_SA */
		queued->time = now;
		array_insert(this->queued_tasks, ARRAY_HEAD, queued);
	}
}

METHOD(task_manager_t, busy, bool,
	private_task_manager_t *this)
{
	return array_count(this->active_tasks) > 0;
}

METHOD(task_manager_t, reset, void,
	private_task_manager_t *this, uint32_t initiate, uint32_t respond)
{
	enumerator_t *enumerator;
	queued_task_t *queued;
	task_t *task;
	timeval_t now;

	/* reset message counters and retransmit packets */
	clear_packets(this->responding.packets);
	clear_packets(this->initiating.packets);
	DESTROY_IF(this->responding.defrag);
	DESTROY_IF(this->initiating.defrag);
	this->responding.defrag = NULL;
	this->initiating.defrag = NULL;
	if (initiate != UINT_MAX)
	{
		this->initiating.mid = initiate;
	}
	if (respond != UINT_MAX)
	{
		this->responding.mid = respond;
	}
	this->initiating.type = EXCHANGE_TYPE_UNDEFINED;

	time_monotonic(&now);
	/* reset queued tasks */
	enumerator = array_create_enumerator(this->queued_tasks);
	while (enumerator->enumerate(enumerator, &queued))
	{
		queued->time = now;
		queued->task->migrate(queued->task, this->ike_sa);
	}
	enumerator->destroy(enumerator);

	/* reset active tasks */
	while (array_remove(this->active_tasks, ARRAY_TAIL, &task))
	{
		task->migrate(task, this->ike_sa);
		INIT(queued,
			.task = task,
			.time = now,
		);
		array_insert(this->queued_tasks, ARRAY_HEAD, queued);
	}

	this->reset = TRUE;
}

/**
 * Data for a task queue enumerator
 */
typedef struct {
	enumerator_t public;
	task_queue_t queue;
	enumerator_t *inner;
	queued_task_t *queued;
} task_enumerator_t;

METHOD(enumerator_t, task_enumerator_destroy, void,
	task_enumerator_t *this)
{
	this->inner->destroy(this->inner);
	free(this);
}

METHOD(enumerator_t, task_enumerator_enumerate, bool,
	task_enumerator_t *this, va_list args)
{
	task_t **task;

	VA_ARGS_VGET(args, task);
	if (this->queue == TASK_QUEUE_QUEUED)
	{
		if (this->inner->enumerate(this->inner, &this->queued))
		{
			*task = this->queued->task;
			return TRUE;
		}
	}
	else if (this->inner->enumerate(this->inner, task))
	{
		return TRUE;
	}
	return FALSE;
}

METHOD(task_manager_t, create_task_enumerator, enumerator_t*,
	private_task_manager_t *this, task_queue_t queue)
{
	task_enumerator_t *enumerator;

	INIT(enumerator,
		.public = {
			.enumerate = enumerator_enumerate_default,
			.venumerate = _task_enumerator_enumerate,
			.destroy = _task_enumerator_destroy,
		},
		.queue = queue,
	);
	switch (queue)
	{
		case TASK_QUEUE_ACTIVE:
			enumerator->inner = array_create_enumerator(this->active_tasks);
			break;
		case TASK_QUEUE_PASSIVE:
			enumerator->inner = array_create_enumerator(this->passive_tasks);
			break;
		case TASK_QUEUE_QUEUED:
			enumerator->inner = array_create_enumerator(this->queued_tasks);
			break;
		default:
			enumerator->inner = enumerator_create_empty();
			break;
	}
	return &enumerator->public;
}

METHOD(task_manager_t, remove_task, void,
	private_task_manager_t *this, enumerator_t *enumerator_public)
{
	task_enumerator_t *enumerator = (task_enumerator_t*)enumerator_public;

	switch (enumerator->queue)
	{
		case TASK_QUEUE_ACTIVE:
			array_remove_at(this->active_tasks, enumerator->inner);
			break;
		case TASK_QUEUE_PASSIVE:
			array_remove_at(this->passive_tasks, enumerator->inner);
			break;
		case TASK_QUEUE_QUEUED:
			array_remove_at(this->queued_tasks, enumerator->inner);
			free(enumerator->queued);
			enumerator->queued = NULL;
			break;
		default:
			break;
	}
}

METHOD(task_manager_t, destroy, void,
	private_task_manager_t *this)
{
	flush(this);

	array_destroy(this->active_tasks);
	array_destroy(this->queued_tasks);
	array_destroy(this->passive_tasks);

	clear_packets(this->responding.packets);
	array_destroy(this->responding.packets);
	clear_packets(this->initiating.packets);
	array_destroy(this->initiating.packets);
	DESTROY_IF(this->responding.defrag);
	DESTROY_IF(this->initiating.defrag);
	free(this);
}

/*
 * see header file
 */
task_manager_v2_t *task_manager_v2_create(ike_sa_t *ike_sa)
{
	private_task_manager_t *this;

	INIT(this,
		.public = {
			.task_manager = {
				.process_message = _process_message,
				.queue_task = _queue_task,
				.queue_task_delayed = _queue_task_delayed,
				.queue_ike = _queue_ike,
				.queue_ike_rekey = _queue_ike_rekey,
				.queue_ike_reauth = _queue_ike_reauth,
				.queue_ike_delete = _queue_ike_delete,
				.queue_mobike = _queue_mobike,
				.queue_child = _queue_child,
				.queue_child_rekey = _queue_child_rekey,
				.queue_child_delete = _queue_child_delete,
				.queue_dpd = _queue_dpd,
				.initiate = _initiate,
				.retransmit = _retransmit,
				.incr_mid = _incr_mid,
				.get_mid = _get_mid,
				.reset = _reset,
				.adopt_tasks = _adopt_tasks,
				.busy = _busy,
				.create_task_enumerator = _create_task_enumerator,
				.remove_task = _remove_task,
				.flush = _flush,
				.flush_queue = _flush_queue,
				.destroy = _destroy,
			},
		},
		.ike_sa = ike_sa,
		.initiating.type = EXCHANGE_TYPE_UNDEFINED,
		.queued_tasks = array_create(0, 0),
		.active_tasks = array_create(0, 0),
		.passive_tasks = array_create(0, 0),
		.make_before_break = lib->settings->get_bool(lib->settings,
					"%s.make_before_break", TRUE, lib->ns),
	);

	retransmission_parse_default(&this->retransmit);

	return &this->public;
}
