/** @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);
}