1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 Ng Peng Nam Sean
5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
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/param.h>
30 #include <sys/kernel.h>
31 #include <sys/malloc.h>
32 #include <sys/module.h>
33
34 #include <sys/lock.h>
35 #include <sys/rmlock.h>
36 #include <sys/ck.h>
37 #include <sys/syslog.h>
38
39 #include <netlink/netlink.h>
40 #include <netlink/netlink_ctl.h>
41 #include <netlink/netlink_var.h>
42 #include <netlink/route/route_var.h>
43
44 #include <machine/atomic.h>
45
46 FEATURE(netlink, "Netlink support");
47
48 #define DEBUG_MOD_NAME nl_mod
49 #define DEBUG_MAX_LEVEL LOG_DEBUG3
50 #include <netlink/netlink_debug.h>
51 _DECLARE_DEBUG(LOG_INFO);
52
53
54 #define NL_MAX_HANDLERS 20
55 struct nl_proto_handler _nl_handlers[NL_MAX_HANDLERS];
56 struct nl_proto_handler *nl_handlers = _nl_handlers;
57
58 CK_LIST_HEAD(nl_control_head, nl_control);
59 static struct nl_control_head vnets_head = CK_LIST_HEAD_INITIALIZER();
60
61 VNET_DEFINE(struct nl_control *, nl_ctl) = NULL;
62
63 struct mtx nl_global_mtx;
64 MTX_SYSINIT(nl_global_mtx, &nl_global_mtx, "global netlink lock", MTX_DEF);
65
66 #define NL_GLOBAL_LOCK() mtx_lock(&nl_global_mtx)
67 #define NL_GLOBAL_UNLOCK() mtx_unlock(&nl_global_mtx)
68
69 int netlink_unloading = 0;
70
71 static void
free_nl_ctl(struct nl_control * ctl)72 free_nl_ctl(struct nl_control *ctl)
73 {
74 rm_destroy(&ctl->ctl_lock);
75 free(ctl, M_NETLINK);
76 }
77
78 struct nl_control *
vnet_nl_ctl_init(void)79 vnet_nl_ctl_init(void)
80 {
81 struct nl_control *ctl;
82
83 ctl = malloc(sizeof(struct nl_control), M_NETLINK, M_WAITOK | M_ZERO);
84 rm_init(&ctl->ctl_lock, "netlink lock");
85 CK_LIST_INIT(&ctl->ctl_port_head);
86 CK_LIST_INIT(&ctl->ctl_pcb_head);
87
88 NL_GLOBAL_LOCK();
89
90 struct nl_control *tmp = atomic_load_ptr(&V_nl_ctl);
91
92 if (tmp == NULL) {
93 atomic_store_ptr(&V_nl_ctl, ctl);
94 CK_LIST_INSERT_HEAD(&vnets_head, ctl, ctl_next);
95 NL_LOG(LOG_DEBUG2, "VNET %p init done, inserted %p into global list",
96 curvnet, ctl);
97 } else {
98 NL_LOG(LOG_DEBUG, "per-VNET init clash, dropping this instance");
99 free_nl_ctl(ctl);
100 ctl = tmp;
101 }
102
103 NL_GLOBAL_UNLOCK();
104
105 return (ctl);
106 }
107
108 static void
vnet_nl_ctl_destroy(const void * unused __unused)109 vnet_nl_ctl_destroy(const void *unused __unused)
110 {
111 struct nl_control *ctl;
112
113 /* Assume at the time all of the processes / sockets are dead */
114
115 NL_GLOBAL_LOCK();
116 ctl = atomic_load_ptr(&V_nl_ctl);
117 atomic_store_ptr(&V_nl_ctl, NULL);
118 if (ctl != NULL) {
119 NL_LOG(LOG_DEBUG2, "Removing %p from global list", ctl);
120 CK_LIST_REMOVE(ctl, ctl_next);
121 }
122 NL_GLOBAL_UNLOCK();
123
124 if (ctl != NULL)
125 free_nl_ctl(ctl);
126 }
127 VNET_SYSUNINIT(vnet_nl_ctl_destroy, SI_SUB_PROTO_IF, SI_ORDER_ANY,
128 vnet_nl_ctl_destroy, NULL);
129
130 int
nl_verify_proto(int proto)131 nl_verify_proto(int proto)
132 {
133 if (proto < 0 || proto >= NL_MAX_HANDLERS) {
134 return (EINVAL);
135 }
136 int handler_defined = nl_handlers[proto].cb != NULL;
137 return (handler_defined ? 0 : EPROTONOSUPPORT);
138 }
139
140 const char *
nl_get_proto_name(int proto)141 nl_get_proto_name(int proto)
142 {
143 return (nl_handlers[proto].proto_name);
144 }
145
146 bool
netlink_register_proto(int proto,const char * proto_name,nl_handler_f handler)147 netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler)
148 {
149 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
150 return (false);
151 NL_GLOBAL_LOCK();
152 KASSERT((nl_handlers[proto].cb == NULL), ("netlink handler %d is already set", proto));
153 nl_handlers[proto].cb = handler;
154 nl_handlers[proto].proto_name = proto_name;
155 NL_GLOBAL_UNLOCK();
156 NL_LOG(LOG_DEBUG2, "Registered netlink %s(%d) handler", proto_name, proto);
157 return (true);
158 }
159
160 bool
netlink_unregister_proto(int proto)161 netlink_unregister_proto(int proto)
162 {
163 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
164 return (false);
165 NL_GLOBAL_LOCK();
166 KASSERT((nl_handlers[proto].cb != NULL), ("netlink handler %d is not set", proto));
167 nl_handlers[proto].cb = NULL;
168 nl_handlers[proto].proto_name = NULL;
169 NL_GLOBAL_UNLOCK();
170 NL_LOG(LOG_DEBUG2, "Unregistered netlink proto %d handler", proto);
171 return (true);
172 }
173
174 #if !defined(NETLINK) && defined(NETLINK_MODULE)
175 /* Non-stub function provider */
176 const static struct nl_function_wrapper nl_module = {
177 .nlmsg_add = _nlmsg_add,
178 .nlmsg_refill_buffer = _nlmsg_refill_buffer,
179 .nlmsg_flush = _nlmsg_flush,
180 .nlmsg_end = _nlmsg_end,
181 .nlmsg_abort = _nlmsg_abort,
182 .nl_writer_unicast = _nl_writer_unicast,
183 .nl_writer_group = _nl_writer_group,
184 .nlmsg_end_dump = _nlmsg_end_dump,
185 .nl_modify_ifp_generic = _nl_modify_ifp_generic,
186 .nl_store_ifp_cookie = _nl_store_ifp_cookie,
187 .nl_get_thread_nlp = _nl_get_thread_nlp,
188 };
189 #endif
190
191 static bool
can_unload(void)192 can_unload(void)
193 {
194 struct nl_control *ctl;
195 bool result = true;
196
197 NL_GLOBAL_LOCK();
198
199 CK_LIST_FOREACH(ctl, &vnets_head, ctl_next) {
200 NL_LOG(LOG_DEBUG2, "Iterating VNET head %p", ctl);
201 if (!CK_LIST_EMPTY(&ctl->ctl_pcb_head)) {
202 NL_LOG(LOG_NOTICE, "non-empty socket list in ctl %p", ctl);
203 result = false;
204 break;
205 }
206 }
207
208 NL_GLOBAL_UNLOCK();
209
210 return (result);
211 }
212
213 static int
netlink_modevent(module_t mod __unused,int what,void * priv __unused)214 netlink_modevent(module_t mod __unused, int what, void *priv __unused)
215 {
216 int ret = 0;
217
218 switch (what) {
219 case MOD_LOAD:
220 NL_LOG(LOG_DEBUG2, "Loading");
221 nl_osd_register();
222 #if !defined(NETLINK) && defined(NETLINK_MODULE)
223 nl_set_functions(&nl_module);
224 #endif
225 break;
226
227 case MOD_UNLOAD:
228 NL_LOG(LOG_DEBUG2, "Unload called");
229 if (can_unload()) {
230 NL_LOG(LOG_WARNING, "unloading");
231 netlink_unloading = 1;
232 #if !defined(NETLINK) && defined(NETLINK_MODULE)
233 nl_set_functions(NULL);
234 #endif
235 nl_osd_unregister();
236 } else
237 ret = EBUSY;
238 break;
239
240 default:
241 ret = EOPNOTSUPP;
242 break;
243 }
244
245 return (ret);
246 }
247 static moduledata_t netlink_mod = { "netlink", netlink_modevent, NULL };
248
249 DECLARE_MODULE(netlink, netlink_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
250 MODULE_VERSION(netlink, 1);
251