1 /*
2 * net/tipc/user_reg.c: TIPC user registry code
3 *
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2004-2005, Wind River Systems
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36
37 #include "core.h"
38 #include "user_reg.h"
39
40 /*
41 * TIPC user registry keeps track of users of the tipc_port interface.
42 *
43 * The registry utilizes an array of "TIPC user" entries;
44 * a user's ID is the index of their associated array entry.
45 * Array entry 0 is not used, so userid 0 is not valid;
46 * TIPC sometimes uses this value to denote an anonymous user.
47 * The list of free entries is initially chained from last entry to entry 1.
48 */
49
50 /**
51 * struct tipc_user - registered TIPC user info
52 * @next: index of next free registry entry (or -1 for an allocated entry)
53 * @callback: ptr to routine to call when TIPC mode changes (NULL if none)
54 * @usr_handle: user-defined value passed to callback routine
55 * @ports: list of user ports owned by the user
56 */
57
58 struct tipc_user {
59 int next;
60 tipc_mode_event callback;
61 void *usr_handle;
62 struct list_head ports;
63 };
64
65 #define MAX_USERID 64
66 #define USER_LIST_SIZE ((MAX_USERID + 1) * sizeof(struct tipc_user))
67
68 static struct tipc_user *users = NULL;
69 static u32 next_free_user = MAX_USERID + 1;
70 static DEFINE_SPINLOCK(reg_lock);
71
72 /**
73 * reg_init - create TIPC user registry (but don't activate it)
74 *
75 * If registry has been pre-initialized it is left "as is".
76 * NOTE: This routine may be called when TIPC is inactive.
77 */
78
reg_init(void)79 static int reg_init(void)
80 {
81 u32 i;
82
83 spin_lock_bh(®_lock);
84 if (!users) {
85 users = kzalloc(USER_LIST_SIZE, GFP_ATOMIC);
86 if (users) {
87 for (i = 1; i <= MAX_USERID; i++) {
88 users[i].next = i - 1;
89 }
90 next_free_user = MAX_USERID;
91 }
92 }
93 spin_unlock_bh(®_lock);
94 return users ? 0 : -ENOMEM;
95 }
96
97 /**
98 * reg_callback - inform TIPC user about current operating mode
99 */
100
reg_callback(struct tipc_user * user_ptr)101 static void reg_callback(struct tipc_user *user_ptr)
102 {
103 tipc_mode_event cb;
104 void *arg;
105
106 spin_lock_bh(®_lock);
107 cb = user_ptr->callback;
108 arg = user_ptr->usr_handle;
109 spin_unlock_bh(®_lock);
110
111 if (cb)
112 cb(arg, tipc_mode, tipc_own_addr);
113 }
114
115 /**
116 * tipc_reg_start - activate TIPC user registry
117 */
118
tipc_reg_start(void)119 int tipc_reg_start(void)
120 {
121 u32 u;
122 int res;
123
124 if ((res = reg_init()))
125 return res;
126
127 for (u = 1; u <= MAX_USERID; u++) {
128 if (users[u].callback)
129 tipc_k_signal((Handler)reg_callback,
130 (unsigned long)&users[u]);
131 }
132 return 0;
133 }
134
135 /**
136 * tipc_reg_stop - shut down & delete TIPC user registry
137 */
138
tipc_reg_stop(void)139 void tipc_reg_stop(void)
140 {
141 int id;
142
143 if (!users)
144 return;
145
146 for (id = 1; id <= MAX_USERID; id++) {
147 if (users[id].callback)
148 reg_callback(&users[id]);
149 }
150 kfree(users);
151 users = NULL;
152 }
153
154 /**
155 * tipc_attach - register a TIPC user
156 *
157 * NOTE: This routine may be called when TIPC is inactive.
158 */
159
tipc_attach(u32 * userid,tipc_mode_event cb,void * usr_handle)160 int tipc_attach(u32 *userid, tipc_mode_event cb, void *usr_handle)
161 {
162 struct tipc_user *user_ptr;
163
164 if ((tipc_mode == TIPC_NOT_RUNNING) && !cb)
165 return -ENOPROTOOPT;
166 if (!users)
167 reg_init();
168
169 spin_lock_bh(®_lock);
170 if (!next_free_user) {
171 spin_unlock_bh(®_lock);
172 return -EBUSY;
173 }
174 user_ptr = &users[next_free_user];
175 *userid = next_free_user;
176 next_free_user = user_ptr->next;
177 user_ptr->next = -1;
178 spin_unlock_bh(®_lock);
179
180 user_ptr->callback = cb;
181 user_ptr->usr_handle = usr_handle;
182 INIT_LIST_HEAD(&user_ptr->ports);
183 atomic_inc(&tipc_user_count);
184
185 if (cb && (tipc_mode != TIPC_NOT_RUNNING))
186 tipc_k_signal((Handler)reg_callback, (unsigned long)user_ptr);
187 return 0;
188 }
189
190 /**
191 * tipc_detach - deregister a TIPC user
192 */
193
tipc_detach(u32 userid)194 void tipc_detach(u32 userid)
195 {
196 struct tipc_user *user_ptr;
197 struct list_head ports_temp;
198 struct user_port *up_ptr, *temp_up_ptr;
199
200 if ((userid == 0) || (userid > MAX_USERID))
201 return;
202
203 spin_lock_bh(®_lock);
204 if ((!users) || (users[userid].next >= 0)) {
205 spin_unlock_bh(®_lock);
206 return;
207 }
208
209 user_ptr = &users[userid];
210 user_ptr->callback = NULL;
211 INIT_LIST_HEAD(&ports_temp);
212 list_splice(&user_ptr->ports, &ports_temp);
213 user_ptr->next = next_free_user;
214 next_free_user = userid;
215 spin_unlock_bh(®_lock);
216
217 atomic_dec(&tipc_user_count);
218
219 list_for_each_entry_safe(up_ptr, temp_up_ptr, &ports_temp, uport_list) {
220 tipc_deleteport(up_ptr->ref);
221 }
222 }
223
224 /**
225 * tipc_reg_add_port - register a user's driver port
226 */
227
tipc_reg_add_port(struct user_port * up_ptr)228 int tipc_reg_add_port(struct user_port *up_ptr)
229 {
230 struct tipc_user *user_ptr;
231
232 if (up_ptr->user_ref == 0)
233 return 0;
234 if (up_ptr->user_ref > MAX_USERID)
235 return -EINVAL;
236 if ((tipc_mode == TIPC_NOT_RUNNING) || !users )
237 return -ENOPROTOOPT;
238
239 spin_lock_bh(®_lock);
240 user_ptr = &users[up_ptr->user_ref];
241 list_add(&up_ptr->uport_list, &user_ptr->ports);
242 spin_unlock_bh(®_lock);
243 return 0;
244 }
245
246 /**
247 * tipc_reg_remove_port - deregister a user's driver port
248 */
249
tipc_reg_remove_port(struct user_port * up_ptr)250 int tipc_reg_remove_port(struct user_port *up_ptr)
251 {
252 if (up_ptr->user_ref == 0)
253 return 0;
254 if (up_ptr->user_ref > MAX_USERID)
255 return -EINVAL;
256 if (!users )
257 return -ENOPROTOOPT;
258
259 spin_lock_bh(®_lock);
260 list_del_init(&up_ptr->uport_list);
261 spin_unlock_bh(®_lock);
262 return 0;
263 }
264
265