xref: /freebsd/sys/netlink/netlink_sysevent.c (revision ee507b70f150855cfff0ef1080c38a3c70c1e7cd)
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 
46 MALLOC_DEFINE(M_NLSE, "nlsysevent", "Memory used for Netlink sysevent");
47 #define	NLSE_FAMILY_NAME	"nlsysevent"
48 static uint16_t ctrl_family_id;
49 
50 #define MAX_SYSEVENT_GROUPS	64
51 static struct sysevent_group {
52 	char *name;
53 	uint32_t id;
54 } sysevent_groups[MAX_SYSEVENT_GROUPS] = {};
55 
56 static 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 
79 static void
sysevent_write(struct sysevent_group * se,const char * subsystem,const char * type,const char * data)80 sysevent_write(struct sysevent_group *se, const char *subsystem, const char *type,
81     const char *data)
82 {
83 	struct nl_writer nw;
84 
85 	if (!nl_writer_group(&nw, NLMSG_LARGE, NETLINK_GENERIC, se->id, 0,
86 	    false)) {
87 		NL_LOG(LOG_DEBUG, "error allocating group writer");
88 		return;
89 	}
90 	struct nlmsghdr hdr = { .nlmsg_type = ctrl_family_id };
91 	if (!nlmsg_reply(&nw, &hdr, sizeof(struct genlmsghdr))) {
92 		return;
93 	}
94 
95 	struct genlmsghdr *ghdr = nlmsg_reserve_object(&nw, struct genlmsghdr);
96 	if (ghdr == NULL) {
97 		NL_LOG(LOG_DEBUG, "unable to allocate memory");
98 		return;
99 	}
100 	ghdr->version = 0;
101 	ghdr->cmd = NLSE_CMD_NEWEVENT;
102 	ghdr->reserved = 0;
103 	nlattr_add_string(&nw, NLSE_ATTR_SYSTEM, se->name);
104 	nlattr_add_string(&nw, NLSE_ATTR_SUBSYSTEM, subsystem);
105 	nlattr_add_string(&nw, NLSE_ATTR_TYPE, type);
106 	if (data != NULL)
107 		nlattr_add_string(&nw, NLSE_ATTR_DATA, data);
108 	nlmsg_end(&nw);
109 	nlmsg_flush(&nw);
110 }
111 
112 static void
sysevent_new_group(size_t index,const char * name)113 sysevent_new_group(size_t index, const char *name)
114 {
115 	if (index >= MAX_SYSEVENT_GROUPS) {
116 		NL_LOG(LOG_WARNING, "impossible to add the event %s, "
117 		    "too many event groups\n", name);
118 		return;
119 	}
120 	sysevent_groups[index].name = strdup(name, M_NLSE);
121 	sysevent_groups[index].id = genl_register_group(ctrl_family_id,
122 	    sysevent_groups[index].name);
123 }
124 
125 static struct sysevent_group *
sysevent_get_group(const char * system)126 sysevent_get_group(const char *system)
127 {
128 	for (size_t i = 0; i < MAX_SYSEVENT_GROUPS; i++) {
129 		if (sysevent_groups[i].name == NULL) {
130 			sysevent_new_group(i, system);
131 			return (&sysevent_groups[i]);
132 		}
133 		if (strcmp(sysevent_groups[i].name, system) == 0)
134 			return (&sysevent_groups[i]);
135 	}
136 
137 	return (NULL);
138 }
139 
140 static void
sysevent_send(const char * system,const char * subsystem,const char * type,const char * data)141 sysevent_send(const char *system, const char *subsystem, const char *type,
142     const char *data)
143 {
144 	struct sysevent_group *se = sysevent_get_group(system);
145 
146 	if (se == NULL) {
147 		NL_LOG(LOG_WARNING, "impossible to add the event %s, "
148 		    "too many event groups\n", system);
149 		return;
150 	}
151 
152 	CURVNET_SET(vnet0);
153 	sysevent_write(se, subsystem, type, data);
154 	CURVNET_RESTORE();
155 }
156 
157 static void
nlsysevent_load(void)158 nlsysevent_load(void)
159 {
160 	devctl_set_notify_hook(sysevent_send);
161 	ctrl_family_id = genl_register_family(NLSE_FAMILY_NAME, 0, 2, NLSE_ATTR_MAX);
162 	for (size_t i = 0; i < nitems(devctl_systems); i++) {
163 		if (i >= MAX_SYSEVENT_GROUPS) {
164 			NL_LOG(LOG_WARNING, "impossible to add the event %s, too many events\n", devctl_systems[i]);
165 			continue;
166 		}
167 		sysevent_new_group(i, devctl_systems[i]);
168 	}
169 }
170 
171 static void
nlsysevent_unload(void)172 nlsysevent_unload(void)
173 {
174 	devctl_unset_notify_hook();
175 	genl_unregister_family(ctrl_family_id);
176 	for (size_t i = 0; i < MAX_SYSEVENT_GROUPS; i++) {
177 		if (sysevent_groups[i].name == NULL)
178 			break;
179 		free(sysevent_groups[i].name, M_NLSE);
180 	}
181 }
182 
183 static int
nlsysevent_loader(module_t mod __unused,int what,void * priv __unused)184 nlsysevent_loader(module_t mod __unused, int what, void *priv __unused)
185 {
186 	int err = 0;
187 
188 	switch (what) {
189 	case MOD_LOAD:
190 		nlsysevent_load();
191 		break;
192 	case MOD_UNLOAD:
193 		nlsysevent_unload();
194 		break;
195 	default:
196 		err = EOPNOTSUPP;
197 		break;
198 	}
199 	return (err);
200 }
201 static moduledata_t nlsysevent_mod = { "nlsysevent", nlsysevent_loader, NULL};
202 
203 DECLARE_MODULE(nlsysevent, nlsysevent_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
204 MODULE_DEPEND(nlsysevent, netlink, 1, 1, 1);
205 MODULE_VERSION(nlsysevent, 1);
206