git: 8a2af0b469b6 - main - nlsysevent: add a genetlink(4) module to report kernel events
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Date: Thu, 01 Jun 2023 21:02:28 UTC
The branch main has been updated by bapt:
URL: https://cgit.FreeBSD.org/src/commit/?id=8a2af0b469b6d65ee48f2352ca56225b36d32342
commit 8a2af0b469b6d65ee48f2352ca56225b36d32342
Author: Baptiste Daroussin <bapt@FreeBSD.org>
AuthorDate: 2023-06-01 21:02:06 +0000
Commit: Baptiste Daroussin <bapt@FreeBSD.org>
CommitDate: 2023-06-01 21:02:06 +0000
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
---
sys/modules/Makefile | 1 +
sys/modules/nlsysevent/Makefile | 11 +++
sys/netlink/netlink_sysevent.c | 168 ++++++++++++++++++++++++++++++++++++++++
sys/netlink/netlink_sysevent.h | 40 ++++++++++
4 files changed, 220 insertions(+)
diff --git a/sys/modules/Makefile b/sys/modules/Makefile
index b9867f25df4e..f14dd383221f 100644
--- a/sys/modules/Makefile
+++ b/sys/modules/Makefile
@@ -282,6 +282,7 @@ SUBDIR= \
nfsd \
nfslockd \
nfssvc \
+ nlsysevent \
nge \
nmdm \
nullfs \
diff --git a/sys/modules/nlsysevent/Makefile b/sys/modules/nlsysevent/Makefile
new file mode 100644
index 000000000000..d7d2100e3e66
--- /dev/null
+++ b/sys/modules/nlsysevent/Makefile
@@ -0,0 +1,11 @@
+# $FreeBSD$
+
+.PATH: ${SRCTOP}/sys/netlink/
+
+KMOD= nlsysevent
+SRCS= netlink_sysevent.c
+
+CFLAGS+= -I${SRCTOP}/sys/contrib/netlink
+EXPORT_SYMS= yes
+
+.include <bsd.kmod.mk>
diff --git a/sys/netlink/netlink_sysevent.c b/sys/netlink/netlink_sysevent.c
new file mode 100644
index 000000000000..67f18a3e2fe7
--- /dev/null
+++ b/sys/netlink/netlink_sysevent.c
@@ -0,0 +1,168 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Baptiste Daroussin <bapt@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/devctl.h>
+#include <sys/errno.h>
+#include <sys/module.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <net/vnet.h>
+#include <netlink/netlink.h>
+#include <netlink/netlink_ctl.h>
+#include <netlink/netlink_generic.h>
+
+#include "netlink_sysevent.h"
+
+#define DEBUG_MOD_NAME nl_sysevent
+#define DEBUG_MAX_LEVEL LOG_DEBUG3
+#include <netlink/netlink_debug.h>
+_DECLARE_DEBUG(LOG_INFO);
+
+MALLOC_DEFINE(M_NLSE, "nlsysevent", "Memory used for Netlink sysevent");
+#define NLSE_FAMILY_NAME "nlsysevent"
+static uint32_t ctrl_family_id;
+
+#define MAX_SYSEVENTS 64
+static struct sysevent {
+ char *name;
+ uint32_t id;
+} sysevents[MAX_SYSEVENTS] = {};
+
+static void
+sysevent_write(struct sysevent *se, const char *subsystem, const char *type,
+ const char *data)
+{
+ struct nl_writer nw = {};
+
+ if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_GENERIC, se->id)) {
+ NL_LOG(LOG_DEBUG, "error allocating group writer");
+ return;
+ }
+ struct nlmsghdr hdr = { .nlmsg_type = ctrl_family_id };
+ if (!nlmsg_reply(&nw, &hdr, sizeof(struct genlmsghdr))) {
+ return;
+ }
+
+ struct genlmsghdr *ghdr = nlmsg_reserve_object(&nw, struct genlmsghdr);
+ if (ghdr == NULL) {
+ NL_LOG(LOG_DEBUG, "unable to allocate memory");
+ return;
+ }
+ ghdr->version = 0;
+ ghdr->cmd = 0;
+ ghdr->reserved = 0;
+ nlattr_add_string(&nw, NLSE_ATTR_SYSTEM, se->name);
+ nlattr_add_string(&nw, NLSE_ATTR_SUBSYSTEM, subsystem);
+ nlattr_add_string(&nw, NLSE_ATTR_TYPE, type);
+ if (data != NULL)
+ nlattr_add_string(&nw, NLSE_ATTR_DATA, data);
+ nlmsg_end(&nw);
+ nlmsg_flush(&nw);
+}
+
+static void
+sysevent_send(const char *system, const char *subsystem, const char *type,
+ const char *data)
+{
+ struct sysevent *se = NULL;
+
+ for (size_t i = 0; i < MAX_SYSEVENTS; i++) {
+ if (sysevents[i].name == NULL) {
+ sysevents[i].name = strdup(system, M_NLSE);
+ sysevents[i].id = genl_register_group(NLSE_FAMILY_NAME,
+ system);
+ se = &sysevents[i];
+ break;
+ }
+ if (strcmp(sysevents[i].name, system) == 0) {
+ se = &sysevents[i];
+ break;
+ }
+ }
+ if (se == NULL) {
+ NL_LOG(LOG_WARNING, "impossible to add the event %s, "
+ "too many events\n", system);
+ return;
+ }
+
+ CURVNET_SET(vnet0);
+ sysevent_write(se, subsystem, type, data);
+ CURVNET_RESTORE();
+}
+
+static void
+nlsysevent_load(void)
+{
+ devctl_set_notify_hook(sysevent_send);
+ ctrl_family_id = genl_register_family(NLSE_FAMILY_NAME, 0, 2, NLSE_ATTR_MAX);
+ for (size_t i = 0; i < nitems(devctl_systems); i++) {
+ if (i >= MAX_SYSEVENTS) {
+ NL_LOG(LOG_WARNING, "impossible to add the event %s, too many events\n", devctl_systems[i]);
+ continue;
+ }
+ sysevents[i].name = strdup(devctl_systems[i], M_NLSE);
+ sysevents[i].id = genl_register_group(NLSE_FAMILY_NAME, devctl_systems[i]);
+ }
+}
+
+static void
+nlsysevent_unload(void)
+{
+ devctl_unset_notify_hook();
+ genl_unregister_family(NLSE_FAMILY_NAME);
+ for (size_t i = 0; i < MAX_SYSEVENTS; i++) {
+ if (sysevents[i].name == NULL)
+ break;
+ free(sysevents[i].name, M_NLSE);
+ }
+}
+
+static int
+nlsysevent_loader(module_t mod __unused, int what, void *priv __unused)
+{
+ int err = 0;
+
+ switch (what) {
+ case MOD_LOAD:
+ nlsysevent_load();
+ break;
+ case MOD_UNLOAD:
+ nlsysevent_unload();
+ break;
+ default:
+ err = EOPNOTSUPP;
+ break;
+ }
+ return (err);
+}
+static moduledata_t nlsysevent_mod = { "nlsysevent", nlsysevent_loader, NULL};
+
+DECLARE_MODULE(nlsysevent, nlsysevent_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
+MODULE_DEPEND(nlsysevent, netlink, 1, 1, 1);
+MODULE_VERSION(nlsysevent, 1);
diff --git a/sys/netlink/netlink_sysevent.h b/sys/netlink/netlink_sysevent.h
new file mode 100644
index 000000000000..23288d2dd5c3
--- /dev/null
+++ b/sys/netlink/netlink_sysevent.h
@@ -0,0 +1,40 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Baptiste Daroussin <bapt@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _NETLINK_SYSEVENT_H_
+#define _NETLINK_SYSEVENT_H_
+
+enum {
+ NLSE_ATTR_UNSPEC = 0,
+ NLSE_ATTR_SYSTEM = 1,
+ NLSE_ATTR_SUBSYSTEM = 2,
+ NLSE_ATTR_TYPE = 3,
+ NLSE_ATTR_DATA = 4,
+ __NLSE_ATTR_MAX,
+};
+#define NLSE_ATTR_MAX (__NLSE_ATTR_MAX -1)
+#endif