1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/module.h>
35
36 #include <sys/lock.h>
37 #include <sys/rmlock.h>
38 #include <sys/ck.h>
39 #include <sys/syslog.h>
40
41 #include <netlink/netlink.h>
42 #include <netlink/netlink_ctl.h>
43 #include <netlink/netlink_var.h>
44
45 #include <machine/atomic.h>
46
47 MALLOC_DEFINE(M_NETLINK, "netlink", "Memory used for netlink packets");
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_DEBUG);
53
54 SYSCTL_NODE(_net, OID_AUTO, netlink, CTLFLAG_RD, 0, "");
55 SYSCTL_NODE(_net_netlink, OID_AUTO, debug, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
56
57 #define NL_MAX_HANDLERS 20
58 struct nl_proto_handler _nl_handlers[NL_MAX_HANDLERS];
59 struct nl_proto_handler *nl_handlers = _nl_handlers;
60
61 CK_LIST_HEAD(nl_control_head, nl_control);
62 static struct nl_control_head vnets_head = CK_LIST_HEAD_INITIALIZER();
63
64 VNET_DEFINE(struct nl_control *, nl_ctl) = NULL;
65
66 struct mtx nl_global_mtx;
67 MTX_SYSINIT(nl_global_mtx, &nl_global_mtx, "global netlink lock", MTX_DEF);
68
69 #define NL_GLOBAL_LOCK() mtx_lock(&nl_global_mtx)
70 #define NL_GLOBAL_UNLOCK() mtx_unlock(&nl_global_mtx)
71
72 int netlink_unloading = 0;
73
74 static void
75 free_nl_ctl(struct nl_control *ctl)
76 {
77 rm_destroy(&ctl->ctl_lock);
78 free(ctl, M_NETLINK);
79 }
80
81 struct nl_control *
82 vnet_nl_ctl_init(void)
83 {
84 struct nl_control *ctl;
85
86 ctl = malloc(sizeof(struct nl_control), M_NETLINK, M_WAITOK | M_ZERO);
87 rm_init(&ctl->ctl_lock, "netlink lock");
88 CK_LIST_INIT(&ctl->ctl_port_head);
89 CK_LIST_INIT(&ctl->ctl_pcb_head);
90
91 NL_GLOBAL_LOCK();
92
93 struct nl_control *tmp = atomic_load_ptr(&V_nl_ctl);
94
95 if (tmp == NULL) {
96 atomic_store_ptr(&V_nl_ctl, ctl);
97 CK_LIST_INSERT_HEAD(&vnets_head, ctl, ctl_next);
98 NL_LOG(LOG_DEBUG2, "VNET %p init done, inserted %p into global list",
99 curvnet, ctl);
100 } else {
101 NL_LOG(LOG_DEBUG, "per-VNET init clash, dropping this instance");
102 free_nl_ctl(ctl);
103 ctl = tmp;
104 }
105
106 NL_GLOBAL_UNLOCK();
107
108 return (ctl);
109 }
110
111 static void
112 vnet_nl_ctl_destroy(const void *unused __unused)
113 {
114 struct nl_control *ctl;
115
116 /* Assume at the time all of the processes / sockets are dead */
117
118 NL_GLOBAL_LOCK();
119 ctl = atomic_load_ptr(&V_nl_ctl);
120 atomic_store_ptr(&V_nl_ctl, NULL);
121 if (ctl != NULL) {
122 NL_LOG(LOG_DEBUG2, "Removing %p from global list", ctl);
123 CK_LIST_REMOVE(ctl, ctl_next);
124 }
125 NL_GLOBAL_UNLOCK();
126
127 if (ctl != NULL)
128 free_nl_ctl(ctl);
129 }
130 VNET_SYSUNINIT(vnet_nl_ctl_destroy, SI_SUB_PROTO_IF, SI_ORDER_ANY,
131 vnet_nl_ctl_destroy, NULL);
132
133 int
134 nl_verify_proto(int proto)
135 {
136 if (proto < 0 || proto >= NL_MAX_HANDLERS) {
137 return (EINVAL);
138 }
139 int handler_defined = nl_handlers[proto].cb != NULL;
140 return (handler_defined ? 0 : EPROTONOSUPPORT);
141 }
142
143 const char *
144 nl_get_proto_name(int proto)
145 {
146 return (nl_handlers[proto].proto_name);
147 }
148
149 bool
150 netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler)
151 {
152 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
153 return (false);
154 NL_GLOBAL_LOCK();
155 KASSERT((nl_handlers[proto].cb == NULL), ("netlink handler %d is already set", proto));
156 nl_handlers[proto].cb = handler;
157 nl_handlers[proto].proto_name = proto_name;
158 NL_GLOBAL_UNLOCK();
159 NL_LOG(LOG_DEBUG, "Registered netlink %s(%d) handler", proto_name, proto);
160 return (true);
161 }
162
163 bool
164 netlink_unregister_proto(int proto)
165 {
166 if ((proto < 0) || (proto >= NL_MAX_HANDLERS))
167 return (false);
168 NL_GLOBAL_LOCK();
169 KASSERT((nl_handlers[proto].cb != NULL), ("netlink handler %d is not set", proto));
170 nl_handlers[proto].cb = NULL;
171 nl_handlers[proto].proto_name = NULL;
172 NL_GLOBAL_UNLOCK();
173 NL_LOG(LOG_DEBUG, "Unregistered netlink proto %d handler", proto);
174 return (true);
175 }
176
177 static bool
178 can_unload(void)
179 {
180 struct nl_control *ctl;
181 bool result = true;
182
183 NL_GLOBAL_LOCK();
184
185 CK_LIST_FOREACH(ctl, &vnets_head, ctl_next) {
186 NL_LOG(LOG_DEBUG2, "Iterating VNET head %p", ctl);
187 if (!CK_LIST_EMPTY(&ctl->ctl_pcb_head)) {
188 NL_LOG(LOG_NOTICE, "non-empty socket list in ctl %p", ctl);
189 result = false;
190 break;
191 }
192 }
193
194 NL_GLOBAL_UNLOCK();
195
196 return (result);
197 }
198
199 static int
200 netlink_modevent(module_t mod __unused, int what, void *priv __unused)
201 {
202 int ret = 0;
203
204 switch (what) {
205 case MOD_LOAD:
206 NL_LOG(LOG_DEBUG, "Loading");
207 NL_LOG(LOG_NOTICE, "netlink support is in BETA stage");
208 break;
209
210 case MOD_UNLOAD:
211 NL_LOG(LOG_DEBUG, "Unload called");
212 if (can_unload()) {
213 NL_LOG(LOG_WARNING, "unloading");
214 netlink_unloading = 1;
215 } else
216 ret = EBUSY;
217 break;
218
219 default:
220 ret = EOPNOTSUPP;
221 break;
222 }
223
224 return (ret);
225 }
226 static moduledata_t netlink_mod = { "netlink", netlink_modevent, NULL };
227
228 DECLARE_MODULE(netlink, netlink_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
229 MODULE_VERSION(netlink, 1);
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