Root/net/tipc/user_reg.c

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 = NULL;
69static u32 next_free_user = MAX_USERID + 1;
70static 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
79static int reg_init(void)
80{
81    u32 i;
82
83    spin_lock_bh(&reg_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(&reg_lock);
94    return users ? 0 : -ENOMEM;
95}
96
97/**
98 * reg_callback - inform TIPC user about current operating mode
99 */
100
101static void reg_callback(struct tipc_user *user_ptr)
102{
103    tipc_mode_event cb;
104    void *arg;
105
106    spin_lock_bh(&reg_lock);
107    cb = user_ptr->callback;
108    arg = user_ptr->usr_handle;
109    spin_unlock_bh(&reg_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
119int 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
139void 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
160int 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(&reg_lock);
170    if (!next_free_user) {
171        spin_unlock_bh(&reg_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(&reg_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
194void 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(&reg_lock);
204    if ((!users) || (users[userid].next >= 0)) {
205        spin_unlock_bh(&reg_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(&reg_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
228int 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(&reg_lock);
240    user_ptr = &users[up_ptr->user_ref];
241    list_add(&up_ptr->uport_list, &user_ptr->ports);
242    spin_unlock_bh(&reg_lock);
243    return 0;
244}
245
246/**
247 * tipc_reg_remove_port - deregister a user's driver port
248 */
249
250int 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(&reg_lock);
260    list_del_init(&up_ptr->uport_list);
261    spin_unlock_bh(&reg_lock);
262    return 0;
263}
264
265

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