DHCP plugin framework, send DHCP Discover upon IP request

src/libcharon/plugins/dhcp/dhcp_provider.c

@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec 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 "dhcp_provider.h"
+
+#include <utils/hashtable.h>
+#include <threading/mutex.h>
+
+typedef struct private_dhcp_provider_t private_dhcp_provider_t;
+
+/**
+ * Private data of an dhcp_provider_t object.
+ */
+struct private_dhcp_provider_t {
+
+	/**
+	 * Public dhcp_provider_t interface.
+	 */
+	dhcp_provider_t public;
+
+	/**
+	 * Completed DHCP transactions
+	 */
+	hashtable_t *transactions;
+
+	/**
+	 * Lock for transactions
+	 */
+	mutex_t *mutex;
+
+	/**
+	 * DHCP communication socket
+	 */
+	dhcp_socket_t *socket;
+};
+
+/**
+ * Hashtable hash function
+ */
+static u_int hash(void *key)
+{
+	return (uintptr_t)key;
+}
+
+/**
+ * Hashtable equals function
+ */
+static bool equals(void *a, void *b)
+{
+	return a == b;
+}
+
+/**
+ * Hash ID and host to a key
+ */
+static uintptr_t hash_id_host(identification_t *id, host_t *host)
+{
+	return chunk_hash_inc(id->get_encoding(id),
+						  chunk_hash(host->get_address(host)));
+}
+
+/**
+ * Hash a DHCP transaction to a key, using address and id
+ */
+static uintptr_t hash_transaction(dhcp_transaction_t *transaction)
+{
+	return hash_id_host(transaction->get_identity(transaction),
+						transaction->get_address(transaction));
+}
+
+METHOD(attribute_provider_t, acquire_address, host_t*,
+	private_dhcp_provider_t *this, char *pool,
+	identification_t *id, host_t *requested)
+{
+	if (streq(pool, "dhcp"))
+	{
+		dhcp_transaction_t *transaction, *old;
+		host_t *vip;
+
+		transaction = this->socket->enroll(this->socket, id);
+		if (!transaction)
+		{
+			return NULL;
+		}
+		vip = transaction->get_address(transaction);
+		vip = vip->clone(vip);
+		this->mutex->lock(this->mutex);
+		old = this->transactions->put(this->transactions,
+							(void*)hash_transaction(transaction), transaction);
+		this->mutex->unlock(this->mutex);
+		DESTROY_IF(old);
+		return vip;
+	}
+	return NULL;
+}
+
+METHOD(attribute_provider_t, release_address, bool,
+	private_dhcp_provider_t *this, char *pool,
+	host_t *address, identification_t *id)
+{
+	if (streq(pool, "dhcp"))
+	{
+		dhcp_transaction_t *transaction;
+
+		this->mutex->lock(this->mutex);
+		transaction = this->transactions->remove(this->transactions,
+										(void*)hash_id_host(id, address));
+		this->mutex->unlock(this->mutex);
+		if (transaction)
+		{
+			transaction->destroy(transaction);
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
+METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
+	private_dhcp_provider_t *this, identification_t *id, host_t *vip)
+{
+	return enumerator_create_empty();
+}
+
+METHOD(dhcp_provider_t, destroy, void,
+	private_dhcp_provider_t *this)
+{
+	enumerator_t *enumerator;
+	dhcp_transaction_t *value;
+	void *key;
+
+	enumerator = this->transactions->create_enumerator(this->transactions);
+	while (enumerator->enumerate(enumerator, &key, &value))
+	{
+		value->destroy(value);
+	}
+	enumerator->destroy(enumerator);
+	this->transactions->destroy(this->transactions);
+	this->mutex->destroy(this->mutex);
+	free(this);
+}
+
+/**
+ * See header
+ */
+dhcp_provider_t *dhcp_provider_create(dhcp_socket_t *socket)
+{
+	private_dhcp_provider_t *this;
+
+	INIT(this,
+		.public = {
+			.provider = {
+				.acquire_address = _acquire_address,
+				.release_address = _release_address,
+				.create_attribute_enumerator = _create_attribute_enumerator,
+			},
+			.destroy = _destroy,
+		},
+		.socket = socket,
+		.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
+		.transactions = hashtable_create(hash, equals, 8),
+	);
+
+	return &this->public;
+}
+