/*
* acpi_ids.c - ACPI Netlink Group and Family IDs
*
* Copyright (C) 2008 Ted Felix (www.tedfelix.com)
* Portions from acpi_genl Copyright (C) Zhang Rui <rui.zhang@intel.com>
*
* 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.
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
/* needed by netlink.h, should be in there */
#include <arpa/inet.h>
#include <linux/types.h>
#include <string.h>
#include "genetlink.h"
#include "libnetlink.h"
#include "acpi_ids.h"
#define GENL_MAX_FAM_GRPS 256
#define ACPI_EVENT_FAMILY_NAME "acpi_event"
#define ACPI_EVENT_MCAST_GROUP_NAME "acpi_mc_group"
static int initialized = 0;
static __u16 acpi_event_family_id = 0;
static __u32 acpi_event_mcast_group_id = 0;
/*
* A CTRL_CMD_GETFAMILY message returns an attribute table that looks
* like this:
*
* CTRL_ATTR_FAMILY_ID Use this to make sure we get the proper msgs
* CTRL_ATTR_MCAST_GROUPS
* CTRL_ATTR_MCAST_GRP_NAME
* CTRL_ATTR_MCAST_GRP_ID Need this for the group mask
* ...
*/
static int
get_ctrl_grp_id(struct rtattr *arg)
{
struct rtattr *tb[CTRL_ATTR_MCAST_GRP_MAX + 1];
char *name;
if (arg == NULL)
return -1;
/* nested within the CTRL_ATTR_MCAST_GROUPS attribute are the */
/* group name and ID */
parse_rtattr_nested(tb, CTRL_ATTR_MCAST_GRP_MAX, arg);
/* if either of the entries needed cannot be found, bail */
if (!tb[CTRL_ATTR_MCAST_GRP_NAME] || !tb[CTRL_ATTR_MCAST_GRP_ID])
return -1;
/* get the name of this multicast group we've found */
name = RTA_DATA(tb[CTRL_ATTR_MCAST_GRP_NAME]);
/* if it does not match the ACPI event multicast group name, bail */
if (strcmp(name, ACPI_EVENT_MCAST_GROUP_NAME))
return -1;
/* At this point, we've found what we were looking for. We now */
/* have the multicast group ID for ACPI events over generic netlink. */
acpi_event_mcast_group_id =
*((__u32 *)RTA_DATA(tb[CTRL_ATTR_MCAST_GRP_ID]));
return 0;
}
/* n = the response to a CTRL_CMD_GETFAMILY message */
static int
genl_get_mcast_group_id(struct nlmsghdr *n)
{
/*
* Attribute table. Note the type name "rtattr" which means "route
* attribute". This is a vestige of one of netlink's main uses:
* routing.
*/
struct rtattr *tb[CTRL_ATTR_MAX + 1];
/* place for the generic netlink header in the incoming message */
struct genlmsghdr ghdr;
/* length of the attribute and payload */
int len = n->nlmsg_len - NLMSG_LENGTH(GENL_HDRLEN);
/* Pointer to the attribute portion of the message */
struct rtattr *attrs;
if (len < 0) {
printf("Netlink: CTRL_CMD_GETFAMILY response, "
"wrong controller message len: %d\n", len);
return -1;
}
if (n->nlmsg_type != GENL_ID_CTRL) {
printf("Netlink: Not a controller message, nlmsg_len=%d "
"nlmsg_type=0x%x\n", n->nlmsg_len, n->nlmsg_type);
return 0;
}
/* copy generic netlink header into structure */
memcpy(&ghdr, NLMSG_DATA(n), GENL_HDRLEN);
if (ghdr.cmd != CTRL_CMD_GETFAMILY &&
ghdr.cmd != CTRL_CMD_DELFAMILY &&
ghdr.cmd != CTRL_CMD_NEWFAMILY &&
ghdr.cmd != CTRL_CMD_NEWMCAST_GRP &&
ghdr.cmd != CTRL_CMD_DELMCAST_GRP) {
printf("Netlink: Unknown controller command %d\n", ghdr.cmd);
return 0;
}
/* set attrs to point to the attribute */
attrs = (struct rtattr *)(NLMSG_DATA(n) + GENL_HDRLEN);
/* Read the table from the message into "tb". This actually just */
/* places pointers into the message into tb[]. */
parse_rtattr(tb, CTRL_ATTR_MAX, attrs, len);
/* if a family ID attribute is present, get it */
if (tb[CTRL_ATTR_FAMILY_ID])
{
acpi_event_family_id =
*((__u32 *)RTA_DATA(tb[CTRL_ATTR_FAMILY_ID]));
}
/* if a "multicast groups" attribute is present... */
if (tb[CTRL_ATTR_MCAST_GROUPS]) {
struct rtattr *tb2[GENL_MAX_FAM_GRPS + 1];
int i;
/* get the group table within this attribute */
parse_rtattr_nested(tb2, GENL_MAX_FAM_GRPS,
tb[CTRL_ATTR_MCAST_GROUPS]);
/* for each group */
for (i = 0; i < GENL_MAX_FAM_GRPS; i++)
/* if this group is valid */
if (tb2[i])
/* Parse the ID. If successful, we're done. */
if (!get_ctrl_grp_id(tb2[i]))
return 0;
}
return -1;
}
static int
genl_get_ids(char *family_name)
{
/* handle to the netlink connection */
struct rtnl_handle rth;
/* holds the request we are going to send and the reply */
struct {
struct nlmsghdr n;
char buf[4096]; /* ??? Is this big enough for all cases? */
} req;
/* pointer to the nlmsghdr in req */
struct nlmsghdr *nlh;
/* place for the generic netlink header before copied into req */
struct genlmsghdr ghdr;
/* return value */
int ret = -1;
/* clear out the request */
memset(&req, 0, sizeof(req));
/* set up nlh to point to the netlink header in req */
nlh = &req.n;
/* set up the netlink header */
nlh->nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
nlh->nlmsg_type = GENL_ID_CTRL;
/* clear out the generic netlink message header */
memset(&ghdr, 0, sizeof(struct genlmsghdr));
/* set the command we want to run: "GETFAMILY" */
ghdr.cmd = CTRL_CMD_GETFAMILY;
/* copy it into req */
memcpy(NLMSG_DATA(&req.n), &ghdr, GENL_HDRLEN);
/* the message payload is the family name */
addattr_l(nlh, 128, CTRL_ATTR_FAMILY_NAME,
family_name, strlen(family_name) + 1);
/* open a generic netlink connection */
if (rtnl_open_byproto(&rth, 0, NETLINK_GENERIC) < 0) {
printf("Netlink: Cannot open generic netlink socket\n");
return -1;
}
/*
* Send CTRL_CMD_GETFAMILY message (in nlh) to the generic
* netlink controller. Reply will be in nlh upon return.
*/
if (rtnl_talk(&rth, nlh, 0, 0, nlh, NULL, NULL) < 0) {
printf("Netlink: Error talking to the kernel\n");
goto ctrl_done;
}
/* process the response */
if (genl_get_mcast_group_id(nlh) < 0) {
printf("Netlink: Failed to get acpi_event multicast group\n");
goto ctrl_done;
}
ret = 0;
ctrl_done:
rtnl_close(&rth);
return ret;
}
/* initialize the ACPI IDs */
static void
acpi_ids_init(void)
{
genl_get_ids(ACPI_EVENT_FAMILY_NAME);
initialized = 1;
}
/* returns the netlink family ID for ACPI event messages */
__u16
acpi_ids_getfamily(void)
{
/* if the IDs haven't been initialized, initialize them */
if (initialized == 0)
acpi_ids_init();
return acpi_event_family_id;
}
/* returns the netlink multicast group ID for ACPI event messages */
__u32
acpi_ids_getgroup(void)
{
/* if the IDs haven't been initialized, initialize them */
if (initialized == 0)
acpi_ids_init();
return acpi_event_mcast_group_id;
}