nlsysevent: add a genetlink(4) module to report kernel events
Hooked to devctl_notify, this allows consumers to received events by subscribing to a system over a generic netlink protocol Reviewed by: imp, melifaro Differential Revision: https://reviews.freebsd.org/D37574
This commit is contained in:
Baptiste Daroussin
parent
afbb26b58b
commit
8a2af0b469
@ -282,6 +282,7 @@ SUBDIR= \
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nfsd \
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nfslockd \
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nfssvc \
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nlsysevent \
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nge \
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nmdm \
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nullfs \
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11
sys/modules/nlsysevent/Makefile
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11
sys/modules/nlsysevent/Makefile
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# $FreeBSD$
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.PATH: ${SRCTOP}/sys/netlink/
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KMOD= nlsysevent
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SRCS= netlink_sysevent.c
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CFLAGS+= -I${SRCTOP}/sys/contrib/netlink
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EXPORT_SYMS= yes
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.include <bsd.kmod.mk>
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168
sys/netlink/netlink_sysevent.c
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168
sys/netlink/netlink_sysevent.c
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@ -0,0 +1,168 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2023 Baptiste Daroussin <bapt@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/devctl.h>
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#include <sys/errno.h>
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#include <sys/module.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <net/vnet.h>
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#include <netlink/netlink.h>
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#include <netlink/netlink_ctl.h>
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#include <netlink/netlink_generic.h>
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#include "netlink_sysevent.h"
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#define DEBUG_MOD_NAME nl_sysevent
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#define DEBUG_MAX_LEVEL LOG_DEBUG3
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#include <netlink/netlink_debug.h>
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_DECLARE_DEBUG(LOG_INFO);
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MALLOC_DEFINE(M_NLSE, "nlsysevent", "Memory used for Netlink sysevent");
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#define NLSE_FAMILY_NAME "nlsysevent"
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static uint32_t ctrl_family_id;
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#define MAX_SYSEVENTS 64
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static struct sysevent {
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char *name;
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uint32_t id;
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} sysevents[MAX_SYSEVENTS] = {};
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static void
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sysevent_write(struct sysevent *se, const char *subsystem, const char *type,
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const char *data)
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{
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struct nl_writer nw = {};
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if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_GENERIC, se->id)) {
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NL_LOG(LOG_DEBUG, "error allocating group writer");
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return;
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}
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struct nlmsghdr hdr = { .nlmsg_type = ctrl_family_id };
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if (!nlmsg_reply(&nw, &hdr, sizeof(struct genlmsghdr))) {
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return;
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}
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struct genlmsghdr *ghdr = nlmsg_reserve_object(&nw, struct genlmsghdr);
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if (ghdr == NULL) {
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NL_LOG(LOG_DEBUG, "unable to allocate memory");
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return;
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}
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ghdr->version = 0;
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ghdr->cmd = 0;
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ghdr->reserved = 0;
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nlattr_add_string(&nw, NLSE_ATTR_SYSTEM, se->name);
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nlattr_add_string(&nw, NLSE_ATTR_SUBSYSTEM, subsystem);
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nlattr_add_string(&nw, NLSE_ATTR_TYPE, type);
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if (data != NULL)
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nlattr_add_string(&nw, NLSE_ATTR_DATA, data);
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nlmsg_end(&nw);
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nlmsg_flush(&nw);
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}
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static void
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sysevent_send(const char *system, const char *subsystem, const char *type,
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const char *data)
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{
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struct sysevent *se = NULL;
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for (size_t i = 0; i < MAX_SYSEVENTS; i++) {
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if (sysevents[i].name == NULL) {
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sysevents[i].name = strdup(system, M_NLSE);
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sysevents[i].id = genl_register_group(NLSE_FAMILY_NAME,
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system);
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se = &sysevents[i];
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break;
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}
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if (strcmp(sysevents[i].name, system) == 0) {
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se = &sysevents[i];
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break;
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}
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}
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if (se == NULL) {
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NL_LOG(LOG_WARNING, "impossible to add the event %s, "
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"too many events\n", system);
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return;
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}
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CURVNET_SET(vnet0);
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sysevent_write(se, subsystem, type, data);
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CURVNET_RESTORE();
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}
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static void
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nlsysevent_load(void)
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{
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devctl_set_notify_hook(sysevent_send);
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ctrl_family_id = genl_register_family(NLSE_FAMILY_NAME, 0, 2, NLSE_ATTR_MAX);
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for (size_t i = 0; i < nitems(devctl_systems); i++) {
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if (i >= MAX_SYSEVENTS) {
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NL_LOG(LOG_WARNING, "impossible to add the event %s, too many events\n", devctl_systems[i]);
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continue;
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}
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sysevents[i].name = strdup(devctl_systems[i], M_NLSE);
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sysevents[i].id = genl_register_group(NLSE_FAMILY_NAME, devctl_systems[i]);
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}
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}
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static void
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nlsysevent_unload(void)
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{
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devctl_unset_notify_hook();
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genl_unregister_family(NLSE_FAMILY_NAME);
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for (size_t i = 0; i < MAX_SYSEVENTS; i++) {
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if (sysevents[i].name == NULL)
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break;
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free(sysevents[i].name, M_NLSE);
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}
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}
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static int
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nlsysevent_loader(module_t mod __unused, int what, void *priv __unused)
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{
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int err = 0;
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switch (what) {
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case MOD_LOAD:
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nlsysevent_load();
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break;
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case MOD_UNLOAD:
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nlsysevent_unload();
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break;
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default:
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err = EOPNOTSUPP;
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break;
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}
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return (err);
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}
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static moduledata_t nlsysevent_mod = { "nlsysevent", nlsysevent_loader, NULL};
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DECLARE_MODULE(nlsysevent, nlsysevent_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
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MODULE_DEPEND(nlsysevent, netlink, 1, 1, 1);
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MODULE_VERSION(nlsysevent, 1);
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40
sys/netlink/netlink_sysevent.h
Normal file
40
sys/netlink/netlink_sysevent.h
Normal file
@ -0,0 +1,40 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2023 Baptiste Daroussin <bapt@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _NETLINK_SYSEVENT_H_
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#define _NETLINK_SYSEVENT_H_
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enum {
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NLSE_ATTR_UNSPEC = 0,
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NLSE_ATTR_SYSTEM = 1,
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NLSE_ATTR_SUBSYSTEM = 2,
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NLSE_ATTR_TYPE = 3,
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NLSE_ATTR_DATA = 4,
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__NLSE_ATTR_MAX,
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};
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#define NLSE_ATTR_MAX (__NLSE_ATTR_MAX -1)
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#endif
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