genl.h revision 5e97c3fcce787a5bc0f8ceef43aa3e05195b480a
/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <dlezcano at fr.ibm.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __genl_h
#define __genl_h
/*
* Use this as a good size to allocate generic netlink messages
*/
#define GENLMSG_GOOD_SIZE NLMSG_GOOD_SIZE
#define GENLMSG_DATA(glh) ((void *)(NLMSG_DATA(glh) + GENL_HDRLEN))
/*
* struct genl_handler : the structure which store the netlink handler
* and the family number resulting of the auto-generating id family
* for the generic netlink protocol
*
* @nlh: the netlink socket handler
* @family: the generic netlink family assigned number
*/
struct genl_handler
{
struct nl_handler nlh;
int family;
};
/*
* struct genlmsg : the struct containing the generic netlink message
* format
*
* @nlmsghdr: a netlink message header
* @genlmsghdr: a generic netlink message header pointer
*
*/
/* __attribute__ ((aligned(4))); */
struct genlmsg {
struct nlmsghdr nlmsghdr;
struct genlmsghdr genlmsghdr;
};
static inline int genetlink_len(const struct genlmsg *genlmsg)
{
return ((genlmsg->nlmsghdr.nlmsg_len) - GENL_HDRLEN - NLMSG_HDRLEN);
}
/*
* genetlink_open : resolve family number id and open a generic netlink socket
*
* @handler: a struct genl_handler pointer
* @family: the family name of the generic netlink protocol
*
* Returns 0 on success, < 0 otherwise
*/
int genetlink_open(struct genl_handler *handler, const char *family);
/*
* genetlink_close : close a generic netlink socket
*
* @handler: the handler of the socket to be closed
*
* Returns 0 on success, < 0 otherwise
*/
int genetlink_close(struct genl_handler *handler);
/*
* genetlink_rcv : receive a generic netlink socket, it is up
* to the caller to manage the allocation of the generic netlink message
*
* @handler: the handler of the generic netlink socket
* @genlmsg: the pointer to a generic netlink message pre-allocated
*
* Returns 0 on success, < 0 otherwise
*/
int genetlink_rcv(struct genl_handler *handler, struct genlmsg *genlmsg);
/*
* genetlink_send : send a generic netlink socket, it is up
* to the caller to manage the allocation of the generic netlink message
*
* @handler: the handler of the generic netlink socket
* @genlmsg: the pointer to a generic netlink message pre-allocated
*
* Returns 0 on success, < 0 otherwise
*/
int genetlink_send(struct genl_handler *handler, struct genlmsg *genlmsg);
struct genlmsg *genlmsg_alloc(size_t size);
void genlmsg_free(struct genlmsg *genlmsg);
/*
* genetlink_transaction : send and receive a generic netlink message in one shot
*
* @handler: the handler of the generic netlink socket
* @request: a generic netlink message containing the request to be sent
* @answer: a pre-allocated generic netlink message to receive the response
*
* Returns 0 on success, < 0 otherwise
*/
int genetlink_transaction(struct genl_handler *handler,
struct genlmsg *request, struct genlmsg *answer);
#endif