/*
 * Copyright (C) 2005-2009 Martin Willi
 * Copyright (C) 2005 Jan Hutter
 * Hochschule fuer Technik Rapperswil
 *
 * 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 "ike_auth.h"

#include <string.h>

#include <daemon.h>
#include <encoding/payloads/id_payload.h>
#include <encoding/payloads/auth_payload.h>
#include <encoding/payloads/eap_payload.h>
#include <encoding/payloads/nonce_payload.h>
#include <sa/authenticators/eap_authenticator.h>

typedef struct private_ike_auth_t private_ike_auth_t;

/**
 * Private members of a ike_auth_t task.
 */
struct private_ike_auth_t {

	/**
	 * Public methods and task_t interface.
	 */
	ike_auth_t public;

	/**
	 * Assigned IKE_SA.
	 */
	ike_sa_t *ike_sa;

	/**
	 * Are we the initiator?
	 */
	bool initiator;

	/**
	 * Nonce chosen by us in ike_init
	 */
	chunk_t my_nonce;

	/**
	 * Nonce chosen by peer in ike_init
	 */
	chunk_t other_nonce;

	/**
	 * IKE_SA_INIT message sent by us
	 */
	packet_t *my_packet;

	/**
	 * IKE_SA_INIT message sent by peer
	 */
	packet_t *other_packet;

	/**
	 * currently active authenticator, to authenticate us
	 */
	authenticator_t *my_auth;

	/**
	 * currently active authenticator, to authenticate peer
	 */
	authenticator_t *other_auth;

	/**
	 * peer_cfg candidates, ordered by priority
	 */
	linked_list_t *candidates;

	/**
	 * selected peer config (might change when using multiple authentications)
	 */
	peer_cfg_t *peer_cfg;

	/**
	 * have we planned an(other) authentication exchange?
	 */
	bool do_another_auth;

	/**
	 * has the peer announced another authentication exchange?
	 */
	bool expect_another_auth;

	/**
	 * should we send a AUTHENTICATION_FAILED notify?
	 */
	bool authentication_failed;
};

/**
 * check if multiple authentication extension is enabled, configuration-wise
 */
static bool multiple_auth_enabled()
{
	return lib->settings->get_bool(lib->settings,
								   "charon.multiple_authentication", TRUE);
}

/**
 * collect the needed information in the IKE_SA_INIT exchange from our message
 */
static status_t collect_my_init_data(private_ike_auth_t *this,
									 message_t *message)
{
	nonce_payload_t *nonce;

	/* get the nonce that was generated in ike_init */
	nonce = (nonce_payload_t*)message->get_payload(message, NONCE);
	if (nonce == NULL)
	{
		return FAILED;
	}
	this->my_nonce = nonce->get_nonce(nonce);

	/* pre-generate the message, keep a copy */
	if (this->ike_sa->generate_message(this->ike_sa, message,
									   &this->my_packet) != SUCCESS)
	{
		return FAILED;
	}
	return NEED_MORE;
}

/**
 * collect the needed information in the IKE_SA_INIT exchange from others message
 */
static status_t collect_other_init_data(private_ike_auth_t *this,
										message_t *message)
{
	/* we collect the needed information in the IKE_SA_INIT exchange */
	nonce_payload_t *nonce;

	/* get the nonce that was generated in ike_init */
	nonce = (nonce_payload_t*)message->get_payload(message, NONCE);
	if (nonce == NULL)
	{
		return FAILED;
	}
	this->other_nonce = nonce->get_nonce(nonce);

	/* keep a copy of the received packet */
	this->other_packet = message->get_packet(message);
	return NEED_MORE;
}

/**
 * Get the next authentication configuration
 */
static auth_cfg_t *get_auth_cfg(private_ike_auth_t *this, bool local)
{
	enumerator_t *e1, *e2;
	auth_cfg_t *c1, *c2, *next = NULL;

	/* find an available config not already done */
	e1 = this->peer_cfg->create_auth_cfg_enumerator(this->peer_cfg, local);
	while (e1->enumerate(e1, &c1))
	{
		bool found = FALSE;

		e2 = this->ike_sa->create_auth_cfg_enumerator(this->ike_sa, local);
		while (e2->enumerate(e2, &c2))
		{
			if (c2->complies(c2, c1, FALSE))
			{
				found = TRUE;
				break;
			}
		}
		e2->destroy(e2);
		if (!found)
		{
			next = c1;
			break;
		}
	}
	e1->destroy(e1);
	return next;
}

/**
 * Check if we have should initiate another authentication round
 */
static bool do_another_auth(private_ike_auth_t *this)
{
	bool do_another = FALSE;
	enumerator_t *done, *todo;
	auth_cfg_t *done_cfg, *todo_cfg;

	if (!this->ike_sa->supports_extension(this->ike_sa, EXT_MULTIPLE_AUTH))
	{
		return FALSE;
	}

	done = this->ike_sa->create_auth_cfg_enumerator(this->ike_sa, TRUE);
	todo = this->peer_cfg->create_auth_cfg_enumerator(this->peer_cfg, TRUE);
	while (todo->enumerate(todo, &todo_cfg))
	{
		if (!done->enumerate(done, &done_cfg))
		{
			done_cfg = this->ike_sa->get_auth_cfg(this->ike_sa, TRUE);
		}
		if (!done_cfg->complies(done_cfg, todo_cfg, FALSE))
		{
			do_another = TRUE;
			break;
		}
	}
	done->destroy(done);
	todo->destroy(todo);
	return do_another;
}

/**
 * Get peer configuration candidates from backends
 */
static bool load_cfg_candidates(private_ike_auth_t *this)
{
	enumerator_t *enumerator;
	peer_cfg_t *peer_cfg;
	host_t *me, *other;
	identification_t *my_id, *other_id;

	me = this->ike_sa->get_my_host(this->ike_sa);
	other = this->ike_sa->get_other_host(this->ike_sa);
	my_id = this->ike_sa->get_my_id(this->ike_sa);
	other_id = this->ike_sa->get_other_id(this->ike_sa);

	enumerator = charon->backends->create_peer_cfg_enumerator(charon->backends,
													me, other, my_id, other_id);
	while (enumerator->enumerate(enumerator, &peer_cfg))
	{
		peer_cfg->get_ref(peer_cfg);
		if (this->peer_cfg == NULL)
		{	/* best match */
			this->peer_cfg = peer_cfg;
			this->ike_sa->set_peer_cfg(this->ike_sa, peer_cfg);
		}
		else
		{
			this->candidates->insert_last(this->candidates, peer_cfg);
		}
	}
	enumerator->destroy(enumerator);
	if (this->peer_cfg)
	{
		DBG1(DBG_CFG, "selected peer config '%s'",
			 this->peer_cfg->get_name(this->peer_cfg));
		return TRUE;
	}
	DBG1(DBG_CFG, "no matching peer config found");
	return FALSE;
}

/**
 * update the current peer candidate if necessary, using candidates
 */
static bool update_cfg_candidates(private_ike_auth_t *this, bool strict)
{
	do
	{
		if (this->peer_cfg)
		{
			bool complies = TRUE;
			enumerator_t *e1, *e2, *tmp;
			auth_cfg_t *c1, *c2;

			e1 = this->ike_sa->create_auth_cfg_enumerator(this->ike_sa, FALSE);
			e2 = this->peer_cfg->create_auth_cfg_enumerator(this->peer_cfg, FALSE);

			if (strict)
			{	/* swap lists in strict mode: all configured rounds must be
				 * fulfilled. If !strict, we check only the rounds done so far. */
				tmp = e1;
				e1 = e2;
				e2 = tmp;
			}
			while (e1->enumerate(e1, &c1))
			{
				/* check if done authentications comply to configured ones */
				if ((!e2->enumerate(e2, &c2)) ||
					(!strict && !c1->complies(c1, c2, TRUE)) ||
					(strict && !c2->complies(c2, c1, TRUE)))
				{
					complies = FALSE;
					break;
				}
			}
			e1->destroy(e1);
			e2->destroy(e2);
			if (complies)
			{
				break;
			}
			DBG1(DBG_CFG, "selected peer config '%s' inacceptable",
				 this->peer_cfg->get_name(this->peer_cfg));
			this->peer_cfg->destroy(this->peer_cfg);
		}
		if (this->candidates->remove_first(this->candidates,
										(void**)&this->peer_cfg) != SUCCESS)
		{
			DBG1(DBG_CFG, "no alternative config found");
			this->peer_cfg = NULL;
		}
		else
		{
			DBG1(DBG_CFG, "switching to peer config '%s'",
				 this->peer_cfg->get_name(this->peer_cfg));
			this->ike_sa->set_peer_cfg(this->ike_sa, this->peer_cfg);
		}
	}
	while (this->peer_cfg);

	return this->peer_cfg != NULL;
}

/**
 * Implementation of task_t.build for initiator
 */
static status_t build_i(private_ike_auth_t *this, message_t *message)
{
	auth_cfg_t *cfg;

	if (message->get_exchange_type(message) == IKE_SA_INIT)
	{
		return collect_my_init_data(this, message);
	}

	if (this->peer_cfg == NULL)
	{
		this->peer_cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
		this->peer_cfg->get_ref(this->peer_cfg);
	}

	if (message->get_message_id(message) == 1)
	{	/* in the first IKE_AUTH ... */
		if (this->ike_sa->supports_extension(this->ike_sa, EXT_MULTIPLE_AUTH))
		{	/* indicate support for multiple authentication */
			message->add_notify(message, FALSE, MULTIPLE_AUTH_SUPPORTED,
								chunk_empty);
		}
		/* indicate support for EAP-only authentication */
		message->add_notify(message, FALSE, EAP_ONLY_AUTHENTICATION,
							chunk_empty);
	}

	if (!this->do_another_auth && !this->my_auth)
	{	/* we have done our rounds */
		return NEED_MORE;
	}

	/* check if an authenticator is in progress */
	if (this->my_auth == NULL)
	{
		identification_t *id;
		id_payload_t *id_payload;

		/* clean up authentication config from a previous round */
		cfg = this->ike_sa->get_auth_cfg(this->ike_sa, TRUE);
		cfg->purge(cfg, TRUE);

		/* add (optional) IDr */
		cfg = get_auth_cfg(this, FALSE);
		if (cfg)
		{
			id = cfg->get(cfg, AUTH_RULE_IDENTITY);
			if (id && !id->contains_wildcards(id))
			{
				this->ike_sa->set_other_id(this->ike_sa, id->clone(id));
				id_payload = id_payload_create_from_identification(
															ID_RESPONDER, id);
				message->add_payload(message, (payload_t*)id_payload);
			}
		}
		/* add IDi */
		cfg = this->ike_sa->get_auth_cfg(this->ike_sa, TRUE);
		cfg->merge(cfg, get_auth_cfg(this, TRUE), TRUE);
		id = cfg->get(cfg, AUTH_RULE_IDENTITY);
		if (!id)
		{
			DBG1(DBG_CFG, "configuration misses IDi");
			return FAILED;
		}
		this->ike_sa->set_my_id(this->ike_sa, id->clone(id));
		id_payload = id_payload_create_from_identification(ID_INITIATOR, id);
		message->add_payload(message, (payload_t*)id_payload);

		/* build authentication data */
		this->my_auth = authenticator_create_builder(this->ike_sa, cfg,
							this->other_nonce, this->my_nonce,
							this->other_packet->get_data(this->other_packet),
							this->my_packet->get_data(this->my_packet));
		if (!this->my_auth)
		{
			return FAILED;
		}
	}
	switch (this->my_auth->build(this->my_auth, message))
	{
		case SUCCESS:
			/* authentication step complete, reset authenticator */
			cfg = auth_cfg_create();
			cfg->merge(cfg, this->ike_sa->get_auth_cfg(this->ike_sa, TRUE), TRUE);
			this->ike_sa->add_auth_cfg(this->ike_sa, TRUE, cfg);
			this->my_auth->destroy(this->my_auth);
			this->my_auth = NULL;
			break;
		case NEED_MORE:
			break;
		default:
			return FAILED;
	}

	/* check for additional authentication rounds */
	if (do_another_auth(this))
	{
		if (message->get_payload(message, AUTHENTICATION))
		{
			message->add_notify(message, FALSE, ANOTHER_AUTH_FOLLOWS, chunk_empty);
		}
	}
	else
	{
		this->do_another_auth = FALSE;
	}
	return NEED_MORE;
}

/**
 * Implementation of task_t.process for responder
 */
static status_t process_r(private_ike_auth_t *this, message_t *message)
{
	auth_cfg_t *cfg, *cand;
	id_payload_t *id_payload;
	identification_t *id;

	if (message->get_exchange_type(message) == IKE_SA_INIT)
	{
		return collect_other_init_data(this, message);
	}

	if (this->my_auth == NULL && this->do_another_auth)
	{
		/* handle (optional) IDr payload, apply proposed identity */
		id_payload = (id_payload_t*)message->get_payload(message, ID_RESPONDER);
		if (id_payload)
		{
			id = id_payload->get_identification(id_payload);
		}
		else
		{
			id = identification_create_from_encoding(ID_ANY, chunk_empty);
		}
		this->ike_sa->set_my_id(this->ike_sa, id);
	}

	if (!this->expect_another_auth)
	{
		return NEED_MORE;
	}

	if (message->get_message_id(message) == 1)
	{	/* check for extensions in the first IKE_AUTH */
		if (message->get_notify(message, MULTIPLE_AUTH_SUPPORTED))
		{
			this->ike_sa->enable_extension(this->ike_sa, EXT_MULTIPLE_AUTH);
		}
		if (this->ike_sa->supports_extension(this->ike_sa, EXT_STRONGSWAN) &&
			message->get_notify(message, EAP_ONLY_AUTHENTICATION))
		{	/* EAP-only has no official notify, accept only from strongSwan */
			this->ike_sa->enable_extension(this->ike_sa,
										   EXT_EAP_ONLY_AUTHENTICATION);
		}
	}

	if (this->other_auth == NULL)
	{
		/* handle IDi payload */
		id_payload = (id_payload_t*)message->get_payload(message, ID_INITIATOR);
		if (!id_payload)
		{
			DBG1(DBG_IKE, "IDi payload missing");
			return FAILED;
		}
		id = id_payload->get_identification(id_payload);
		this->ike_sa->set_other_id(this->ike_sa, id);
		cfg = this->ike_sa->get_auth_cfg(this->ike_sa, FALSE);
		cfg->add(cfg, AUTH_RULE_IDENTITY, id->clone(id));

		if (this->peer_cfg == NULL)
		{
			if (!load_cfg_candidates(this))
			{
				this->authentication_failed = TRUE;
				return NEED_MORE;
			}
		}
		if (message->get_payload(message, AUTHENTICATION) == NULL)
		{	/* before authenticating with EAP, we need a EAP config */
			cand = get_auth_cfg(this, FALSE);
			while (!cand || (
					(uintptr_t)cand->get(cand, AUTH_RULE_EAP_TYPE) == EAP_NAK &&
					(uintptr_t)cand->get(cand, AUTH_RULE_EAP_VENDOR) == 0))
			{	/* peer requested EAP, but current config does not match */
				this->peer_cfg->destroy(this->peer_cfg);
				this->peer_cfg = NULL;
				if (!update_cfg_candidates(this, FALSE))
				{
					this->authentication_failed = TRUE;
					return NEED_MORE;
				}
				cand = get_auth_cfg(this, FALSE);
			}
			cfg->merge(cfg, cand, TRUE);
		}

		/* verify authentication data */
		this->other_auth = authenticator_create_verifier(this->ike_sa,
							message, this->other_nonce, this->my_nonce,
							this->other_packet->get_data(this->other_packet),
							this->my_packet->get_data(this->my_packet));
		if (!this->other_auth)
		{
			this->authentication_failed = TRUE;
			return NEED_MORE;
		}
	}
	switch (this->other_auth->process(this->other_auth, message))
	{
		case SUCCESS:
			this->other_auth->destroy(this->other_auth);
			this->other_auth = NULL;
			break;
		case NEED_MORE:
			if (message->get_payload(message, AUTHENTICATION))
			{	/* AUTH verification successful, but another build() needed */
				break;
			}
			return NEED_MORE;
		default:
			this->authentication_failed = TRUE;
			return NEED_MORE;
	}

	/* store authentication information */
	cfg = auth_cfg_create();
	cfg->merge(cfg, this->ike_sa->get_auth_cfg(this->ike_sa, FALSE), FALSE);
	this->ike_sa->add_auth_cfg(this->ike_sa, FALSE, cfg);

	/* another auth round done, invoke authorize hook */
	if (!charon->bus->authorize(charon->bus, FALSE))
	{
		DBG1(DBG_IKE, "authorization hook forbids IKE_SA, cancelling");
		this->authentication_failed = TRUE;
		return NEED_MORE;
	}

	if (!update_cfg_candidates(this, FALSE))
	{
		this->authentication_failed = TRUE;
		return NEED_MORE;
	}

	if (message->get_notify(message, ANOTHER_AUTH_FOLLOWS) == NULL)
	{
		this->expect_another_auth = FALSE;
		if (!update_cfg_candidates(this, TRUE))
		{
			this->authentication_failed = TRUE;
			return NEED_MORE;
		}
	}
	return NEED_MORE;
}

/**
 * Implementation of task_t.build for responder
 */
static status_t build_r(private_ike_auth_t *this, message_t *message)
{
	auth_cfg_t *cfg;

	if (message->get_exchange_type(message) == IKE_SA_INIT)
	{
		if (multiple_auth_enabled())
		{
			message->add_notify(message, FALSE, MULTIPLE_AUTH_SUPPORTED,
								chunk_empty);
		}
		return collect_my_init_data(this, message);
	}

	if (this->authentication_failed || this->peer_cfg == NULL)
	{
		message->add_notify(message, TRUE, AUTHENTICATION_FAILED, chunk_empty);
		return FAILED;
	}

	if (this->my_auth == NULL && this->do_another_auth)
	{
		identification_t *id, *id_cfg;
		id_payload_t *id_payload;

		/* add IDr */
		cfg = this->ike_sa->get_auth_cfg(this->ike_sa, TRUE);
		cfg->purge(cfg, TRUE);
		cfg->merge(cfg, get_auth_cfg(this, TRUE), TRUE);

		id_cfg = cfg->get(cfg, AUTH_RULE_IDENTITY);
		id = this->ike_sa->get_my_id(this->ike_sa);
		if (id->get_type(id) == ID_ANY)
		{	/* no IDr received, apply configured ID */
			if (!id_cfg || id_cfg->contains_wildcards(id_cfg))
			{
				DBG1(DBG_CFG, "IDr not configured and negotiation failed");
				message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
									chunk_empty);
				return FAILED;
			}
			this->ike_sa->set_my_id(this->ike_sa, id_cfg->clone(id_cfg));
			id = id_cfg;
		}
		else
		{	/* IDr received, check if it matches configuration */
			if (id_cfg && !id->matches(id, id_cfg))
			{
				DBG1(DBG_CFG, "received IDr %Y, but require %Y", id, id_cfg);
				message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
									chunk_empty);
				return FAILED;
			}
		}

		id_payload = id_payload_create_from_identification(ID_RESPONDER, id);
		message->add_payload(message, (payload_t*)id_payload);

		if ((uintptr_t)cfg->get(cfg, AUTH_RULE_AUTH_CLASS) == AUTH_CLASS_EAP)
		{	/* EAP-only authentication */
			if (!this->ike_sa->supports_extension(this->ike_sa,
												  EXT_EAP_ONLY_AUTHENTICATION))
			{
				DBG1(DBG_IKE, "configured EAP-only authentication, but peer "
					 "does not support it");
				message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
									chunk_empty);
				return FAILED;
			}
		}
		else
		{
			/* build authentication data */
			this->my_auth = authenticator_create_builder(this->ike_sa, cfg,
								this->other_nonce, this->my_nonce,
								this->other_packet->get_data(this->other_packet),
								this->my_packet->get_data(this->my_packet));
			if (!this->my_auth)
			{
				message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
									chunk_empty);
				return FAILED;
			}
		}
	}

	if (this->other_auth)
	{
		switch (this->other_auth->build(this->other_auth, message))
		{
			case SUCCESS:
				this->other_auth->destroy(this->other_auth);
				this->other_auth = NULL;
				break;
			case NEED_MORE:
				break;
			default:
				if (!message->get_payload(message, EXTENSIBLE_AUTHENTICATION))
				{	/* skip AUTHENTICATION_FAILED if we have EAP_FAILURE */
					message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
										chunk_empty);
				}
				return FAILED;
		}
	}
	if (this->my_auth)
	{
		switch (this->my_auth->build(this->my_auth, message))
		{
			case SUCCESS:
				cfg = auth_cfg_create();
				cfg->merge(cfg, this->ike_sa->get_auth_cfg(this->ike_sa, TRUE),
						   TRUE);
				this->ike_sa->add_auth_cfg(this->ike_sa, TRUE, cfg);
				this->my_auth->destroy(this->my_auth);
				this->my_auth = NULL;
				break;
			case NEED_MORE:
				break;
			default:
				message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
									chunk_empty);
				return FAILED;
		}
	}

	/* check for additional authentication rounds */
	if (do_another_auth(this))
	{
		message->add_notify(message, FALSE, ANOTHER_AUTH_FOLLOWS, chunk_empty);
	}
	else
	{
		this->do_another_auth = FALSE;
	}
	if (!this->do_another_auth && !this->expect_another_auth)
	{
		if (charon->ike_sa_manager->check_uniqueness(charon->ike_sa_manager,
													 this->ike_sa))
		{
			DBG1(DBG_IKE, "cancelling IKE_SA setup due uniqueness policy");
			message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
								chunk_empty);
			return FAILED;
		}
		if (!charon->bus->authorize(charon->bus, TRUE))
		{
			DBG1(DBG_IKE, "final authorization hook forbids IKE_SA, cancelling");
			message->add_notify(message, TRUE, AUTHENTICATION_FAILED,
								chunk_empty);
			return FAILED;
		}
		DBG0(DBG_IKE, "IKE_SA %s[%d] established between %H[%Y]...%H[%Y]",
			 this->ike_sa->get_name(this->ike_sa),
			 this->ike_sa->get_unique_id(this->ike_sa),
			 this->ike_sa->get_my_host(this->ike_sa),
			 this->ike_sa->get_my_id(this->ike_sa),
			 this->ike_sa->get_other_host(this->ike_sa),
			 this->ike_sa->get_other_id(this->ike_sa));
		this->ike_sa->set_state(this->ike_sa, IKE_ESTABLISHED);
		charon->bus->ike_updown(charon->bus, this->ike_sa, TRUE);
		return SUCCESS;
	}
	return NEED_MORE;
}

/**
 * Implementation of task_t.process for initiator
 */
static status_t process_i(private_ike_auth_t *this, message_t *message)
{
	enumerator_t *enumerator;
	payload_t *payload;
	auth_cfg_t *cfg;
	bool mutual_eap = FALSE;

	if (message->get_exchange_type(message) == IKE_SA_INIT)
	{
		if (message->get_notify(message, MULTIPLE_AUTH_SUPPORTED) &&
			multiple_auth_enabled())
		{
			this->ike_sa->enable_extension(this->ike_sa, EXT_MULTIPLE_AUTH);
		}
		return collect_other_init_data(this, message);
	}

	enumerator = message->create_payload_enumerator(message);
	while (enumerator->enumerate(enumerator, &payload))
	{
		if (payload->get_type(payload) == NOTIFY)
		{
			notify_payload_t *notify = (notify_payload_t*)payload;
			notify_type_t type = notify->get_notify_type(notify);

			switch (type)
			{
				case NO_PROPOSAL_CHOSEN:
				case SINGLE_PAIR_REQUIRED:
				case NO_ADDITIONAL_SAS:
				case INTERNAL_ADDRESS_FAILURE:
				case FAILED_CP_REQUIRED:
				case TS_UNACCEPTABLE:
				case INVALID_SELECTORS:
					/* these are errors, but are not critical as only the
					 * CHILD_SA won't get build, but IKE_SA establishes anyway */
					break;
				case MOBIKE_SUPPORTED:
				case ADDITIONAL_IP4_ADDRESS:
				case ADDITIONAL_IP6_ADDRESS:
					/* handled in ike_mobike task */
					break;
				case AUTH_LIFETIME:
					/* handled in ike_auth_lifetime task */
					break;
				case ME_ENDPOINT:
					/* handled in ike_me task */
					break;
				default:
				{
					if (type < 16383)
					{
						DBG1(DBG_IKE, "received %N notify error",
							 notify_type_names, type);
						enumerator->destroy(enumerator);
						return FAILED;
					}
					DBG2(DBG_IKE, "received %N notify",
						notify_type_names, type);
					break;
				}
			}
		}
	}
	enumerator->destroy(enumerator);

	if (this->expect_another_auth)
	{
		if (this->other_auth == NULL)
		{
			id_payload_t *id_payload;
			identification_t *id;

			/* handle IDr payload */
			id_payload = (id_payload_t*)message->get_payload(message,
															 ID_RESPONDER);
			if (!id_payload)
			{
				DBG1(DBG_IKE, "IDr payload missing");
				return FAILED;
			}
			id = id_payload->get_identification(id_payload);
			this->ike_sa->set_other_id(this->ike_sa, id);
			cfg = this->ike_sa->get_auth_cfg(this->ike_sa, FALSE);
			cfg->add(cfg, AUTH_RULE_IDENTITY, id->clone(id));

			if (message->get_payload(message, AUTHENTICATION))
			{
				/* verify authentication data */
				this->other_auth = authenticator_create_verifier(this->ike_sa,
								message, this->other_nonce, this->my_nonce,
								this->other_packet->get_data(this->other_packet),
								this->my_packet->get_data(this->my_packet));
				if (!this->other_auth)
				{
					return FAILED;
				}
			}
			else
			{
				/* responder omitted AUTH payload, indicating EAP-only */
				mutual_eap = TRUE;
			}
		}
		if (this->other_auth)
		{
			switch (this->other_auth->process(this->other_auth, message))
			{
				case SUCCESS:
					break;
				case NEED_MORE:
					return NEED_MORE;
				default:
					return FAILED;
			}
			this->other_auth->destroy(this->other_auth);
			this->other_auth = NULL;
		}
		/* store authentication information, reset authenticator */
		cfg = auth_cfg_create();
		cfg->merge(cfg, this->ike_sa->get_auth_cfg(this->ike_sa, FALSE), FALSE);
		this->ike_sa->add_auth_cfg(this->ike_sa, FALSE, cfg);

		/* another auth round done, invoke authorize hook */
		if (!charon->bus->authorize(charon->bus, FALSE))
		{
			DBG1(DBG_IKE, "authorization forbids IKE_SA, cancelling");
			return FAILED;
		}
	}

	if (this->my_auth)
	{
		switch (this->my_auth->process(this->my_auth, message))
		{
			case SUCCESS:
				cfg = auth_cfg_create();
				cfg->merge(cfg, this->ike_sa->get_auth_cfg(this->ike_sa, TRUE),
						   TRUE);
				this->ike_sa->add_auth_cfg(this->ike_sa, TRUE, cfg);
				this->my_auth->destroy(this->my_auth);
				this->my_auth = NULL;
				this->do_another_auth = do_another_auth(this);
				break;
			case NEED_MORE:
				break;
			default:
				return FAILED;
		}
	}
	if (mutual_eap)
	{
		if (!this->my_auth || !this->my_auth->is_mutual(this->my_auth))
		{
			DBG1(DBG_IKE, "do not allow non-mutual EAP-only authentication");
			return FAILED;
		}
		DBG1(DBG_IKE, "allow mutual EAP-only authentication");
	}

	if (message->get_notify(message, ANOTHER_AUTH_FOLLOWS) == NULL)
	{
		this->expect_another_auth = FALSE;
	}
	if (!this->expect_another_auth && !this->do_another_auth && !this->my_auth)
	{
		if (!update_cfg_candidates(this, TRUE))
		{
			return FAILED;
		}
		if (!charon->bus->authorize(charon->bus, TRUE))
		{
			DBG1(DBG_IKE, "final authorization hook forbids IKE_SA, cancelling");
			return FAILED;
		}
		DBG0(DBG_IKE, "IKE_SA %s[%d] established between %H[%Y]...%H[%Y]",
			 this->ike_sa->get_name(this->ike_sa),
			 this->ike_sa->get_unique_id(this->ike_sa),
			 this->ike_sa->get_my_host(this->ike_sa),
			 this->ike_sa->get_my_id(this->ike_sa),
			 this->ike_sa->get_other_host(this->ike_sa),
			 this->ike_sa->get_other_id(this->ike_sa));
		this->ike_sa->set_state(this->ike_sa, IKE_ESTABLISHED);
		charon->bus->ike_updown(charon->bus, this->ike_sa, TRUE);
		return SUCCESS;
	}
	return NEED_MORE;
}

/**
 * Implementation of task_t.get_type
 */
static task_type_t get_type(private_ike_auth_t *this)
{
	return IKE_AUTHENTICATE;
}

/**
 * Implementation of task_t.migrate
 */
static void migrate(private_ike_auth_t *this, ike_sa_t *ike_sa)
{
	chunk_free(&this->my_nonce);
	chunk_free(&this->other_nonce);
	DESTROY_IF(this->my_packet);
	DESTROY_IF(this->other_packet);
	DESTROY_IF(this->peer_cfg);
	DESTROY_IF(this->my_auth);
	DESTROY_IF(this->other_auth);
	this->candidates->destroy_offset(this->candidates, offsetof(peer_cfg_t, destroy));

	this->my_packet = NULL;
	this->other_packet = NULL;
	this->ike_sa = ike_sa;
	this->peer_cfg = NULL;
	this->my_auth = NULL;
	this->other_auth = NULL;
	this->do_another_auth = TRUE;
	this->expect_another_auth = TRUE;
	this->authentication_failed = FALSE;
	this->candidates = linked_list_create();
}

/**
 * Implementation of task_t.destroy
 */
static void destroy(private_ike_auth_t *this)
{
	chunk_free(&this->my_nonce);
	chunk_free(&this->other_nonce);
	DESTROY_IF(this->my_packet);
	DESTROY_IF(this->other_packet);
	DESTROY_IF(this->my_auth);
	DESTROY_IF(this->other_auth);
	DESTROY_IF(this->peer_cfg);
	this->candidates->destroy_offset(this->candidates, offsetof(peer_cfg_t, destroy));
	free(this);
}

/*
 * Described in header.
 */
ike_auth_t *ike_auth_create(ike_sa_t *ike_sa, bool initiator)
{
	private_ike_auth_t *this = malloc_thing(private_ike_auth_t);

	this->public.task.get_type = (task_type_t(*)(task_t*))get_type;
	this->public.task.migrate = (void(*)(task_t*,ike_sa_t*))migrate;
	this->public.task.destroy = (void(*)(task_t*))destroy;

	if (initiator)
	{
		this->public.task.build = (status_t(*)(task_t*,message_t*))build_i;
		this->public.task.process = (status_t(*)(task_t*,message_t*))process_i;
	}
	else
	{
		this->public.task.build = (status_t(*)(task_t*,message_t*))build_r;
		this->public.task.process = (status_t(*)(task_t*,message_t*))process_r;
	}

	this->ike_sa = ike_sa;
	this->initiator = initiator;
	this->my_nonce = chunk_empty;
	this->other_nonce = chunk_empty;
	this->my_packet = NULL;
	this->other_packet = NULL;
	this->peer_cfg = NULL;
	this->candidates = linked_list_create();
	this->my_auth = NULL;
	this->other_auth = NULL;
	this->do_another_auth = TRUE;
	this->expect_another_auth = TRUE;
	this->authentication_failed = FALSE;

	return &this->public;
}