1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 Ng Peng Nam Sean
5 * Copyright (c) 2022 Alexander V. Chernikov <[email protected]>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33 #include <sys/module.h>
34
35 #include <sys/lock.h>
36 #include <sys/rmlock.h>
37 #include <sys/ck.h>
38 #include <sys/syslog.h>
39
40 #include <netlink/netlink.h>
41 #include <netlink/netlink_ctl.h>
42 #include <netlink/netlink_var.h>
43 #include <netlink/route/route_var.h>
44
45 #include <machine/atomic.h>
46
47 FEATURE(netlink, "Netlink support");
48
49 #define DEBUG_MOD_NAME nl_mod
50 #define DEBUG_MAX_LEVEL LOG_DEBUG3
51 #include <netlink/netlink_debug.h>
52 _DECLARE_DEBUG(LOG_INFO);
53
54
55 #define NL_MAX_HANDLERS 20
56 struct nl_proto_handler _nl_handlers[NL_MAX_HANDLERS];
57 struct nl_proto_handler *nl_handlers = _nl_handlers;
58
59 CK_LIST_HEAD(nl_control_head, nl_control);
60 static struct nl_control_head vnets_head = CK_LIST_HEAD_INITIALIZER();
61
62 VNET_DEFINE(struct nl_control *, nl_ctl) = NULL;
63
64 struct mtx nl_global_mtx;
65 MTX_SYSINIT(nl_global_mtx, &nl_global_mtx, "global netlink lock", MTX_DEF);
66
67 #define NL_GLOBAL_LOCK() mtx_lock(&nl_global_mtx)
68 #define NL_GLOBAL_UNLOCK() mtx_unlock(&nl_global_mtx)
69
70 int netlink_unloading = 0;
71
72 static void
free_nl_ctl(struct nl_control * ctl)73 free_nl_ctl(struct nl_control *ctl)
74 {
75 rm_destroy(&ctl->ctl_lock);
76 free(ctl, M_NETLINK);
77 }
78
79 struct nl_control *
vnet_nl_ctl_init(void)80 vnet_nl_ctl_init(void)
81 {
82 struct nl_control *ctl;
83
84 ctl = malloc(sizeof(struct nl_control), M_NETLINK, M_WAITOK | M_ZERO);
85 rm_init(&ctl->ctl_lock, "netlink lock");
86 CK_LIST_INIT(&ctl->ctl_port_head);
87 CK_LIST_INIT(&ctl->ctl_pcb_head);
88
89 NL_GLOBAL_LOCK();
90
91 struct nl_control *tmp = atomic_load_ptr(&V_nl_ctl);
92
93 if (tmp == NULL) {
94 atomic_store_ptr(&V_nl_ctl, ctl);
95 CK_LIST_INSERT_HEAD(&vnets_head, ctl, ctl_next);
96 NL_LOG(LOG_DEBUG2, "VNET %p init done, inserted %p into global list",
97 curvnet, ctl);
98 } else {
99 NL_LOG(LOG_DEBUG, "per-VNET init clash, dropping this instance");
100 free_nl_ctl(ctl);
101 ctl = tmp;
102 }
103
104 NL_GLOBAL_UNLOCK();
105
106 return (ctl);
107 }
108
109 static void
vnet_nl_ctl_destroy(const void * unused __unused)110 vnet_nl_ctl_destroy(const void *unused __unused)
111 {
112 struct nl_control *ctl;
113
114 /* Assume at the time all of the processes / sockets are dead */
115
116 NL_GLOBAL_LOCK();
117 ctl = atomic_load_ptr(&V_nl_ctl);
118 atomic_store_ptr(&V_nl_ctl, NULL);
119 if (ctl != NULL) {
120 NL_LOG(LOG_DEBUG2, "Removing %p from global list", ctl);
121 CK_LIST_REMOVE(ctl, ctl_next);
122 }
123 NL_GLOBAL_UNLOCK();
124
125 if (ctl != NULL)
126 free_nl_ctl(ctl);
127 }
128 VNET_SYSUNINIT(vnet_nl_ctl_destroy, SI_SUB_PROTO_IF, SI_ORDER_ANY,
129 vnet_nl_ctl_destroy, NULL);
130
131 int
nl_verify_proto(int proto)132 nl_verify_proto(int proto)
133 {
134 if (proto < 0 || proto >= NL_MAX_HANDLERS) {
135 return (EINVAL);
136 }
137 int handler_defined = nl_handlers[proto].cb != NULL;
138 return (handler_defined ? 0 : EPROTONOSUPPORT);
139 }
140
141 const char *
nl_get_proto_name(int proto)142 nl_get_proto_name(int proto)
143 {
144 return (nl_handlers[proto].proto_name);
145 }
146
147 bool
netlink_register_proto(int proto,const char * proto_name,nl_handler_f handler)148 netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler)
149 {
150 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
151 return (false);
152 NL_GLOBAL_LOCK();
153 KASSERT((nl_handlers[proto].cb == NULL), ("netlink handler %d is already set", proto));
154 nl_handlers[proto].cb = handler;
155 nl_handlers[proto].proto_name = proto_name;
156 NL_GLOBAL_UNLOCK();
157 NL_LOG(LOG_DEBUG2, "Registered netlink %s(%d) handler", proto_name, proto);
158 return (true);
159 }
160
161 bool
netlink_unregister_proto(int proto)162 netlink_unregister_proto(int proto)
163 {
164 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
165 return (false);
166 NL_GLOBAL_LOCK();
167 KASSERT((nl_handlers[proto].cb != NULL), ("netlink handler %d is not set", proto));
168 nl_handlers[proto].cb = NULL;
169 nl_handlers[proto].proto_name = NULL;
170 NL_GLOBAL_UNLOCK();
171 NL_LOG(LOG_DEBUG2, "Unregistered netlink proto %d handler", proto);
172 return (true);
173 }
174
175 #if !defined(NETLINK) && defined(NETLINK_MODULE)
176 /* Non-stub function provider */
177 const static struct nl_function_wrapper nl_module = {
178 .nlmsg_add = _nlmsg_add,
179 .nlmsg_refill_buffer = _nlmsg_refill_buffer,
180 .nlmsg_flush = _nlmsg_flush,
181 .nlmsg_end = _nlmsg_end,
182 .nlmsg_abort = _nlmsg_abort,
183 .nlmsg_get_unicast_writer = _nlmsg_get_unicast_writer,
184 .nlmsg_get_group_writer = _nlmsg_get_group_writer,
185 .nlmsg_get_chain_writer = _nlmsg_get_chain_writer,
186 .nlmsg_end_dump = _nlmsg_end_dump,
187 .nl_modify_ifp_generic = _nl_modify_ifp_generic,
188 .nl_store_ifp_cookie = _nl_store_ifp_cookie,
189 .nl_get_thread_nlp = _nl_get_thread_nlp,
190 };
191 #endif
192
193 static bool
can_unload(void)194 can_unload(void)
195 {
196 struct nl_control *ctl;
197 bool result = true;
198
199 NL_GLOBAL_LOCK();
200
201 CK_LIST_FOREACH(ctl, &vnets_head, ctl_next) {
202 NL_LOG(LOG_DEBUG2, "Iterating VNET head %p", ctl);
203 if (!CK_LIST_EMPTY(&ctl->ctl_pcb_head)) {
204 NL_LOG(LOG_NOTICE, "non-empty socket list in ctl %p", ctl);
205 result = false;
206 break;
207 }
208 }
209
210 NL_GLOBAL_UNLOCK();
211
212 return (result);
213 }
214
215 static int
netlink_modevent(module_t mod __unused,int what,void * priv __unused)216 netlink_modevent(module_t mod __unused, int what, void *priv __unused)
217 {
218 int ret = 0;
219
220 switch (what) {
221 case MOD_LOAD:
222 NL_LOG(LOG_DEBUG2, "Loading");
223 nl_init_msg_zone();
224 nl_osd_register();
225 #if !defined(NETLINK) && defined(NETLINK_MODULE)
226 nl_set_functions(&nl_module);
227 #endif
228 break;
229
230 case MOD_UNLOAD:
231 NL_LOG(LOG_DEBUG2, "Unload called");
232 if (can_unload()) {
233 NL_LOG(LOG_WARNING, "unloading");
234 netlink_unloading = 1;
235 #if !defined(NETLINK) && defined(NETLINK_MODULE)
236 nl_set_functions(NULL);
237 #endif
238 nl_osd_unregister();
239 nl_destroy_msg_zone();
240 } else
241 ret = EBUSY;
242 break;
243
244 default:
245 ret = EOPNOTSUPP;
246 break;
247 }
248
249 return (ret);
250 }
251 static moduledata_t netlink_mod = { "netlink", netlink_modevent, NULL };
252
253 DECLARE_MODULE(netlink, netlink_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
254 MODULE_VERSION(netlink, 1);
255