/** @file

 * NetLabel Message Functions

 *

 * Author: Paul Moore <paul@paul-moore.com>

 *

 */

/*

 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 */

#include <stdlib.h>

#include <errno.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <linux/types.h>

#include <libnetlabel.h>

#include "netlabel_internal.h"

/*

 * Allocation Functions

 */

/**

 * Free a NetLabel message

 * @param msg the NetLabel message

 *

 * Free the memory associated with a NetLabel message.

 *

 */

void nlbl_msg_free(nlbl_msg *msg)

{

	if (msg == NULL)

		return;

	nlmsg_free(msg);

}

/**

 * Create a new NetLabel message

 *

 * Creates a new NetLabel message and allocates space for both the Netlink and

 * Generic Netlink headers.

 *

 */

nlbl_msg *nlbl_msg_new(void)

{

	nlbl_msg *msg;

	void *msg_buf;

	msg = nlmsg_alloc();

	if (msg == NULL)

		goto msg_new_failure;

	msg_buf = genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, 0, 0, 0, 0, 0);

	if (msg_buf == NULL)

		goto msg_new_failure;

	return msg;

msg_new_failure:

	nlbl_msg_free(msg);

	return NULL;

}

/*

 * Netlink Header Functions

 */

/**

 * Get the Netlink header from the NetLabel message

 * @param msg the NetLabel message

 *

 * Returns the Netlink header on success, or NULL on failure.

 *

 */

struct nlmsghdr *nlbl_msg_nlhdr(nlbl_msg *msg)

{

	if (msg == NULL)

		return NULL;

	return nlmsg_hdr(msg);

}

/**

 * Get the Generic Netlink header from the NetLabel message

 * @param msg the NetLabel message

 *

 * Returns the Generic Netlink header on success, or NULL on failure.

 *

 */

struct genlmsghdr *nlbl_msg_genlhdr(nlbl_msg *msg)

{

	struct nlmsghdr *nl_hdr;

	/* NOTE: nlbl_msg_nlhdr() can handle being passed a NULL msg */

	nl_hdr = nlbl_msg_nlhdr(msg);

	if (nl_hdr == NULL)

		return NULL;

	return genlmsg_hdr(nl_hdr);

}

/*

 * Netlink Message Functions

 */

/**

 * Return the nlmsgerr struct in the Netlink message

 * @param msg the NetLabel message

 *

 * Returns a pointer to the nlmsgerr struct in a NLMSG_ERROR Netlink message

 * or NULL on failure.

 *

 */

struct nlmsgerr *nlbl_msg_err(nlbl_msg *msg)

{

	struct nlmsghdr *nl_hdr;

	/* NOTE: nlbl_msg_nlhdr() can handle being passed a NULL msg */

	nl_hdr = nlbl_msg_nlhdr(msg);

	if (nl_hdr == NULL || nl_hdr->nlmsg_type != NLMSG_ERROR)

		return NULL;

	return nlmsg_data(nl_hdr);

}

/*

 * Netlink Attribute Functions

 */

/**

 * Get the head of the Netlink attributes from a NetLabel msg

 * @param msg the NetLabel message

 *

 * Returns the head of the Netlink attributes from a NetLabel message on

 * success, or NULL on failure.

 *

 */

struct nlattr *nlbl_attr_head(nlbl_msg *msg)

{

	struct genlmsghdr *genl_hdr;

	/* NOTE: nlbl_msg_genlhdr() can handle being passed a NULL msg */

	genl_hdr = nlbl_msg_genlhdr(msg);

	if (genl_hdr == NULL)

		return NULL;

	return genlmsg_attrdata(genl_hdr, 0);

}

/**

 * Find an attribute in a NetLabel message

 * @param msg the NetLabel message

 * @param nla_type the attribute type

 *

 * Search @msg looking for the @nla_type attribute.  Return the attribute on

 * success, or NULL on failure.

 *

 */

struct nlattr *nlbl_attr_find(nlbl_msg *msg, int nla_type)

{

	struct genlmsghdr *genl_hdr;

	struct nlattr *nla_head;

	/* NOTE: nlbl_msg_genlhdr() can handle being passed a NULL msg */

	genl_hdr = nlbl_msg_genlhdr(msg);

	if (genl_hdr == NULL)

		return NULL;

	nla_head = genlmsg_attrdata(genl_hdr, 0);

	if (nla_head == NULL)

		return NULL;

	return nla_find(nla_head, genlmsg_attrlen(genl_hdr, 0), nla_type);

}