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Linux kernel mirror (for testing)
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linux
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
58struct 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
68static struct tipc_user *users = 0;
69static u32 next_free_user = MAX_USERID + 1;
70static spinlock_t reg_lock = SPIN_LOCK_UNLOCKED;
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
79static int reg_init(void)
80{
81 u32 i;
82
83 spin_lock_bh(®_lock);
84 if (!users) {
85 users = (struct tipc_user *)kmalloc(USER_LIST_SIZE, GFP_ATOMIC);
86 if (users) {
87 memset(users, 0, USER_LIST_SIZE);
88 for (i = 1; i <= MAX_USERID; i++) {
89 users[i].next = i - 1;
90 }
91 next_free_user = MAX_USERID;
92 }
93 }
94 spin_unlock_bh(®_lock);
95 return users ? TIPC_OK : -ENOMEM;
96}
97
98/**
99 * reg_callback - inform TIPC user about current operating mode
100 */
101
102static void reg_callback(struct tipc_user *user_ptr)
103{
104 tipc_mode_event cb;
105 void *arg;
106
107 spin_lock_bh(®_lock);
108 cb = user_ptr->callback;
109 arg = user_ptr->usr_handle;
110 spin_unlock_bh(®_lock);
111
112 if (cb)
113 cb(arg, tipc_mode, tipc_own_addr);
114}
115
116/**
117 * tipc_reg_start - activate TIPC user registry
118 */
119
120int tipc_reg_start(void)
121{
122 u32 u;
123 int res;
124
125 if ((res = reg_init()))
126 return res;
127
128 for (u = 1; u <= MAX_USERID; u++) {
129 if (users[u].callback)
130 tipc_k_signal((Handler)reg_callback,
131 (unsigned long)&users[u]);
132 }
133 return TIPC_OK;
134}
135
136/**
137 * tipc_reg_stop - shut down & delete TIPC user registry
138 */
139
140void tipc_reg_stop(void)
141{
142 int id;
143
144 if (!users)
145 return;
146
147 for (id = 1; id <= MAX_USERID; id++) {
148 if (users[id].callback)
149 reg_callback(&users[id]);
150 }
151 kfree(users);
152 users = 0;
153}
154
155/**
156 * tipc_attach - register a TIPC user
157 *
158 * NOTE: This routine may be called when TIPC is inactive.
159 */
160
161int tipc_attach(u32 *userid, tipc_mode_event cb, void *usr_handle)
162{
163 struct tipc_user *user_ptr;
164
165 if ((tipc_mode == TIPC_NOT_RUNNING) && !cb)
166 return -ENOPROTOOPT;
167 if (!users)
168 reg_init();
169
170 spin_lock_bh(®_lock);
171 if (!next_free_user) {
172 spin_unlock_bh(®_lock);
173 return -EBUSY;
174 }
175 user_ptr = &users[next_free_user];
176 *userid = next_free_user;
177 next_free_user = user_ptr->next;
178 user_ptr->next = -1;
179 spin_unlock_bh(®_lock);
180
181 user_ptr->callback = cb;
182 user_ptr->usr_handle = usr_handle;
183 INIT_LIST_HEAD(&user_ptr->ports);
184 atomic_inc(&tipc_user_count);
185
186 if (cb && (tipc_mode != TIPC_NOT_RUNNING))
187 tipc_k_signal((Handler)reg_callback, (unsigned long)user_ptr);
188 return TIPC_OK;
189}
190
191/**
192 * tipc_detach - deregister a TIPC user
193 */
194
195void tipc_detach(u32 userid)
196{
197 struct tipc_user *user_ptr;
198 struct list_head ports_temp;
199 struct user_port *up_ptr, *temp_up_ptr;
200
201 if ((userid == 0) || (userid > MAX_USERID))
202 return;
203
204 spin_lock_bh(®_lock);
205 if ((!users) || (users[userid].next >= 0)) {
206 spin_unlock_bh(®_lock);
207 return;
208 }
209
210 user_ptr = &users[userid];
211 user_ptr->callback = NULL;
212 INIT_LIST_HEAD(&ports_temp);
213 list_splice(&user_ptr->ports, &ports_temp);
214 user_ptr->next = next_free_user;
215 next_free_user = userid;
216 spin_unlock_bh(®_lock);
217
218 atomic_dec(&tipc_user_count);
219
220 list_for_each_entry_safe(up_ptr, temp_up_ptr, &ports_temp, uport_list) {
221 tipc_deleteport(up_ptr->ref);
222 }
223}
224
225/**
226 * tipc_reg_add_port - register a user's driver port
227 */
228
229int tipc_reg_add_port(struct user_port *up_ptr)
230{
231 struct tipc_user *user_ptr;
232
233 if (up_ptr->user_ref == 0)
234 return TIPC_OK;
235 if (up_ptr->user_ref > MAX_USERID)
236 return -EINVAL;
237 if ((tipc_mode == TIPC_NOT_RUNNING) || !users )
238 return -ENOPROTOOPT;
239
240 spin_lock_bh(®_lock);
241 user_ptr = &users[up_ptr->user_ref];
242 list_add(&up_ptr->uport_list, &user_ptr->ports);
243 spin_unlock_bh(®_lock);
244 return TIPC_OK;
245}
246
247/**
248 * tipc_reg_remove_port - deregister a user's driver port
249 */
250
251int tipc_reg_remove_port(struct user_port *up_ptr)
252{
253 if (up_ptr->user_ref == 0)
254 return TIPC_OK;
255 if (up_ptr->user_ref > MAX_USERID)
256 return -EINVAL;
257 if (!users )
258 return -ENOPROTOOPT;
259
260 spin_lock_bh(®_lock);
261 list_del_init(&up_ptr->uport_list);
262 spin_unlock_bh(®_lock);
263 return TIPC_OK;
264}
265