1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023 Baptiste Daroussin <bapt@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/param.h>
29#include <sys/types.h>
30#include <sys/devctl.h>
31#include <sys/errno.h>
32#include <sys/module.h>
33#include <sys/kernel.h>
34#include <sys/malloc.h>
35#include <net/vnet.h>
36#include <netlink/netlink.h>
37#include <netlink/netlink_ctl.h>
38#include <netlink/netlink_generic.h>
39#include <netlink/netlink_sysevent.h>
40
41#define DEBUG_MOD_NAME  nl_sysevent
42#define DEBUG_MAX_LEVEL LOG_DEBUG3
43#include <netlink/netlink_debug.h>
44_DECLARE_DEBUG(LOG_INFO);
45
46MALLOC_DEFINE(M_NLSE, "nlsysevent", "Memory used for Netlink sysevent");
47#define	NLSE_FAMILY_NAME	"nlsysevent"
48static uint32_t ctrl_family_id;
49
50#define MAX_SYSEVENT_GROUPS	64
51static struct sysevent_group {
52	char *name;
53	uint32_t id;
54} sysevent_groups[MAX_SYSEVENT_GROUPS] = {};
55
56static const char *devctl_systems[] = {
57	"ACPI",
58	"AEON",
59	"CAM",
60	"CARP",
61	"coretemp",
62	"DEVFS",
63	"device",
64	"ETHERNET",
65	"GEOM",
66	"HYPERV_NIC_VF",
67	"IFNET",
68	"INFINIBAND",
69	"KERNEL",
70	"nvme",
71	"PMU",
72	"RCTL",
73	"USB",
74	"VFS",
75	"VT",
76	"ZFS",
77};
78
79static void
80sysevent_write(struct sysevent_group *se, const char *subsystem, const char *type,
81    const char *data)
82{
83	struct nl_writer nw = {};
84
85	if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_GENERIC, se->id)) {
86		NL_LOG(LOG_DEBUG, "error allocating group writer");
87		return;
88	}
89	struct nlmsghdr hdr = { .nlmsg_type = ctrl_family_id };
90	if (!nlmsg_reply(&nw, &hdr, sizeof(struct genlmsghdr))) {
91		return;
92	}
93
94	struct genlmsghdr *ghdr = nlmsg_reserve_object(&nw, struct genlmsghdr);
95	if (ghdr == NULL) {
96		NL_LOG(LOG_DEBUG, "unable to allocate memory");
97		return;
98	}
99	ghdr->version = 0;
100	ghdr->cmd = NLSE_CMD_NEWEVENT;
101	ghdr->reserved = 0;
102	nlattr_add_string(&nw, NLSE_ATTR_SYSTEM, se->name);
103	nlattr_add_string(&nw, NLSE_ATTR_SUBSYSTEM, subsystem);
104	nlattr_add_string(&nw, NLSE_ATTR_TYPE, type);
105	if (data != NULL)
106		nlattr_add_string(&nw, NLSE_ATTR_DATA, data);
107	nlmsg_end(&nw);
108	nlmsg_flush(&nw);
109}
110
111static void
112sysevent_new_group(size_t index, const char *name)
113{
114	if (index >= MAX_SYSEVENT_GROUPS) {
115		NL_LOG(LOG_WARNING, "impossible to add the event %s, "
116		    "too many event groups\n", name);
117		return;
118	}
119	sysevent_groups[index].name = strdup(name, M_NLSE);
120	sysevent_groups[index].id = genl_register_group(NLSE_FAMILY_NAME, sysevent_groups[index].name);
121}
122
123static struct sysevent_group *
124sysevent_get_group(const char *system)
125{
126	for (size_t i = 0; i < MAX_SYSEVENT_GROUPS; i++) {
127		if (sysevent_groups[i].name == NULL) {
128			sysevent_new_group(i, system);
129			return (&sysevent_groups[i]);
130		}
131		if (strcmp(sysevent_groups[i].name, system) == 0)
132			return (&sysevent_groups[i]);
133	}
134
135	return (NULL);
136}
137
138static void
139sysevent_send(const char *system, const char *subsystem, const char *type,
140    const char *data)
141{
142	struct sysevent_group *se = sysevent_get_group(system);
143
144	if (se == NULL) {
145		NL_LOG(LOG_WARNING, "impossible to add the event %s, "
146		    "too many event groups\n", system);
147		return;
148	}
149
150	CURVNET_SET(vnet0);
151	sysevent_write(se, subsystem, type, data);
152	CURVNET_RESTORE();
153}
154
155static void
156nlsysevent_load(void)
157{
158	devctl_set_notify_hook(sysevent_send);
159	ctrl_family_id = genl_register_family(NLSE_FAMILY_NAME, 0, 2, NLSE_ATTR_MAX);
160	for (size_t i = 0; i < nitems(devctl_systems); i++) {
161		if (i >= MAX_SYSEVENT_GROUPS) {
162			NL_LOG(LOG_WARNING, "impossible to add the event %s, too many events\n", devctl_systems[i]);
163			continue;
164		}
165		sysevent_new_group(i, devctl_systems[i]);
166	}
167}
168
169static void
170nlsysevent_unload(void)
171{
172	devctl_unset_notify_hook();
173	genl_unregister_family(NLSE_FAMILY_NAME);
174	for (size_t i = 0; i < MAX_SYSEVENT_GROUPS; i++) {
175		if (sysevent_groups[i].name == NULL)
176			break;
177		free(sysevent_groups[i].name, M_NLSE);
178	}
179}
180
181static int
182nlsysevent_loader(module_t mod __unused, int what, void *priv __unused)
183{
184	int err = 0;
185
186	switch (what) {
187	case MOD_LOAD:
188		nlsysevent_load();
189		break;
190	case MOD_UNLOAD:
191		nlsysevent_unload();
192		break;
193	default:
194		err = EOPNOTSUPP;
195		break;
196	}
197	return (err);
198}
199static moduledata_t nlsysevent_mod = { "nlsysevent", nlsysevent_loader, NULL};
200
201DECLARE_MODULE(nlsysevent, nlsysevent_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
202MODULE_DEPEND(nlsysevent, netlink, 1, 1, 1);
203MODULE_VERSION(nlsysevent, 1);
204