1 files changed, 353 insertions, 0 deletions
diff --git a/src/charon/sa/tasks/child_rekey.c b/src/charon/sa/tasks/child_rekey.c
new file mode 100644
index 000000000..41533b68c
--- /dev/null
+++ b/src/charon/sa/tasks/child_rekey.c
@@ -0,0 +1,353 @@
+/**
+ * @file child_rekey.c
+ *
+ * @brief Implementation of the child_rekey task.
+ *
+ */
+
+/*
+ * Copyright (C) 2005-2007 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 "child_rekey.h"
+
+#include <daemon.h>
+#include <crypto/diffie_hellman.h>
+#include <encoding/payloads/notify_payload.h>
+#include <encoding/payloads/nonce_payload.h>
+#include <sa/tasks/child_create.h>
+
+
+typedef struct private_child_rekey_t private_child_rekey_t;
+
+/**
+ * Private members of a child_rekey_t task.
+ */
+struct private_child_rekey_t {
+	
+	/**
+	 * Public methods and task_t interface.
+	 */
+	child_rekey_t public;
+	
+	/**
+	 * Assigned IKE_SA.
+	 */
+	ike_sa_t *ike_sa;
+	
+	/**
+	 * Are we the initiator?
+	 */
+	bool initiator;
+	
+	/**
+	 * the CHILD_CREATE task which is reused to simplify rekeying
+	 */
+	child_create_t *child_create;
+	
+	/**
+	 * CHILD_SA which gets rekeyed
+	 */
+	child_sa_t *child_sa;
+	
+	/**
+	 * redundandt CHILD_SA created simultaneously
+	 */
+	child_sa_t *simultaneous;
+	
+	/**
+	 * the lowest nonce compared so far
+	 */
+	chunk_t nonce;
+	
+	/**
+	 * TRUE if we have the lower nonce
+	 */
+	bool winner;
+};
+
+/**
+ * get the nonce from a message, return TRUE if it was lower than this->nonce
+ */
+static bool get_nonce(private_child_rekey_t *this, message_t *message)
+{
+	nonce_payload_t *payload;
+	chunk_t nonce;
+	
+	payload = (nonce_payload_t*)message->get_payload(message, NONCE);
+	if (payload == NULL)
+	{
+		return FALSE;
+	}
+	nonce = payload->get_nonce(payload);
+	
+	if (this->nonce.ptr && memcmp(nonce.ptr, this->nonce.ptr,
+								  min(nonce.len, this->nonce.len)) > 0)
+	{
+		chunk_free(&nonce);
+		return FALSE;
+	}
+	
+	chunk_free(&this->nonce);
+	this->nonce = nonce;
+	return TRUE;
+}
+
+/**
+ * find a child using the REKEY_SA notify
+ */
+static void find_child(private_child_rekey_t *this, message_t *message)
+{
+	iterator_t *iterator;
+	payload_t *payload;
+	
+	iterator = message->get_payload_iterator(message);
+	while (iterator->iterate(iterator, (void**)&payload))
+	{
+		notify_payload_t *notify;
+		u_int32_t spi;
+		protocol_id_t protocol;
+		
+		if (payload->get_type(payload) != NOTIFY)
+		{
+			continue;
+		}
+		
+		notify = (notify_payload_t*)payload;
+		protocol = notify->get_protocol_id(notify);
+		spi = notify->get_spi(notify);
+		
+		if (protocol != PROTO_ESP && protocol != PROTO_AH)
+		{
+			continue;
+		}
+		this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
+													spi, FALSE);
+		break;
+			
+	}
+	iterator->destroy(iterator);
+}
+
+#if 0
+/**
+ * handle a detected simultaneous rekeying situation as responder
+ */
+static void simultaneous_r(private_child_rekey_t *this, message_t *message)
+{
+	private_child_rekey_t *other = NULL;
+	task_t *task;
+	iterator_t *iterator;
+	
+	this->ike_sa->create_task_iterator(this->ike_sa);
+	while (iterator->iterate(iterator, (void**)&task))
+	{
+		if (task->get_type(task) == CHILD_REKEY)
+		{
+			other = (private_child_rekey_t*)task;
+			break;
+		}
+	}
+	iterator->destroy(iterator);
+	
+	if (other)
+	{
+		other->simultaneous = this->child_create->get_child(this->child_create);
+	
+		if (!get_nonce(other, message))
+		{
+			/* this wins the race, other lost */
+			other->winner = FALSE;
+		}
+	}
+}
+
+/**
+ * was there a simultaneous rekeying, did we win the nonce compare?
+ */
+static bool simultaneous_i(private_child_rekey_t *this, message_t *message)
+{
+	if (this->winner || get_nonce(this, message))
+	{
+		/* we have the lower nonce and win */
+		return TRUE;
+	}
+	return FALSE;
+}
+#endif
+
+/**
+ * Implementation of task_t.build for initiator
+ */
+static status_t build_i(private_child_rekey_t *this, message_t *message)
+{	
+	notify_payload_t *notify;
+	protocol_id_t protocol;
+	u_int32_t spi, reqid;
+
+	/* our CHILD_CREATE task does the hard work for us... */
+	reqid = this->child_sa->get_reqid(this->child_sa);
+	this->child_create->use_reqid(this->child_create, reqid);
+	this->child_create->task.build(&this->child_create->task, message);
+	get_nonce(this, message);
+	
+	/* ... we just need the rekey notify */
+	protocol = this->child_sa->get_protocol(this->child_sa);
+	spi = this->child_sa->get_spi(this->child_sa, TRUE);
+	notify = notify_payload_create_from_protocol_and_type(protocol, REKEY_SA);
+	notify->set_spi(notify, spi);
+	message->add_payload(message, (payload_t*)notify);
+	
+	this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of task_t.process for initiator
+ */
+static status_t process_r(private_child_rekey_t *this, message_t *message)
+{
+	/* let the CHILD_CREATE task process the message */
+	this->child_create->task.process(&this->child_create->task, message);
+	get_nonce(this, message);
+
+	find_child(this, message);
+	
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of task_t.build for responder
+ */
+static status_t build_r(private_child_rekey_t *this, message_t *message)
+{
+	u_int32_t reqid;
+
+	if (this->child_sa == NULL ||
+		this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
+	{
+		message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
+		return SUCCESS;
+	}
+	
+	/* let the CHILD_CREATE task build the response */
+	reqid = this->child_sa->get_reqid(this->child_sa);
+	this->child_create->use_reqid(this->child_create, reqid);
+	this->child_create->task.build(&this->child_create->task, message);
+	get_nonce(this, message);
+
+	if (this->child_sa->get_state(this->child_sa) == CHILD_REKEYING)
+	{
+		/* simultaneous_detected(this); */
+	}
+	
+	this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+	
+	return SUCCESS;
+}
+
+/**
+ * Implementation of task_t.process for initiator
+ */
+static status_t process_i(private_child_rekey_t *this, message_t *message)
+{
+	protocol_id_t protocol;
+	u_int32_t spi;
+	
+	this->child_create->task.process(&this->child_create->task, message);
+	
+	/*if (!simultaneous_won(this, message))
+	{
+		* delete the redundant CHILD_SA, instead of the rekeyed *
+		this->child_sa = this->create_child->get_child(this->create_child);
+	}*/
+	spi = this->child_sa->get_spi(this->child_sa, TRUE);
+	protocol = this->child_sa->get_protocol(this->child_sa);
+	
+	/* TODO: don't delete when rekeying failed */
+	if (this->ike_sa->delete_child_sa(this->ike_sa, protocol, spi) != SUCCESS)
+	{
+		return FAILED;
+	}
+	return SUCCESS;
+}
+
+/**
+ * Implementation of task_t.get_type
+ */
+static task_type_t get_type(private_child_rekey_t *this)
+{
+	return CHILD_REKEY;
+}
+
+/**
+ * Implementation of task_t.migrate
+ */
+static void migrate(private_child_rekey_t *this, ike_sa_t *ike_sa)
+{	
+	this->child_create->task.migrate(&this->child_create->task, ike_sa);
+	chunk_free(&this->nonce);
+
+	this->ike_sa = ike_sa;
+	this->winner = TRUE;
+	this->simultaneous = NULL;
+}
+
+/**
+ * Implementation of task_t.destroy
+ */
+static void destroy(private_child_rekey_t *this)
+{
+	this->child_create->task.destroy(&this->child_create->task);
+	chunk_free(&this->nonce);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, child_sa_t *child_sa)
+{
+	private_child_rekey_t *this = malloc_thing(private_child_rekey_t);
+	policy_t *policy;
+
+	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 (child_sa != NULL)
+	{
+		this->public.task.build = (status_t(*)(task_t*,message_t*))build_i;
+		this->public.task.process = (status_t(*)(task_t*,message_t*))process_i;
+		this->initiator = TRUE;
+		policy = child_sa->get_policy(child_sa);
+		this->child_create = child_create_create(ike_sa, policy);
+	}
+	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->initiator = FALSE;
+		this->child_create = child_create_create(ike_sa, NULL);
+	}
+	
+	this->ike_sa = ike_sa;
+	this->child_sa = child_sa;
+	this->nonce = chunk_empty;
+	this->winner = TRUE;
+	this->simultaneous = NULL;
+	
+	return &this->public;
+}