summaryrefslogtreecommitdiffstats
path: root/net/tipc/user_reg.c
blob: 35ec7dc8211da8dc234922790c752f65f5e635be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/*
 * net/tipc/user_reg.c: TIPC user registry code
 * 
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2004-2005, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "user_reg.h"

/*
 * TIPC user registry keeps track of users of the tipc_port interface.
 *
 * The registry utilizes an array of "TIPC user" entries; 
 * a user's ID is the index of their associated array entry.
 * Array entry 0 is not used, so userid 0 is not valid;
 * TIPC sometimes uses this value to denote an anonymous user.
 * The list of free entries is initially chained from last entry to entry 1.
 */

/**
 * struct tipc_user - registered TIPC user info
 * @next: index of next free registry entry (or -1 for an allocated entry)
 * @callback: ptr to routine to call when TIPC mode changes (NULL if none)
 * @usr_handle: user-defined value passed to callback routine 
 * @ports: list of user ports owned by the user
 */

struct tipc_user {
	int next;
	tipc_mode_event callback;
	void *usr_handle;
	struct list_head ports;
};

#define MAX_USERID 64
#define USER_LIST_SIZE ((MAX_USERID + 1) * sizeof(struct tipc_user))

static struct tipc_user *users = 0;
static u32 next_free_user = MAX_USERID + 1;
static spinlock_t reg_lock = SPIN_LOCK_UNLOCKED;

/**
 * reg_init - create TIPC user registry (but don't activate it)
 * 
 * If registry has been pre-initialized it is left "as is".
 * NOTE: This routine may be called when TIPC is inactive.
 */

static int reg_init(void)
{
	u32 i;
	
	spin_lock_bh(&reg_lock);
	if (!users) {
		users = (struct tipc_user *)kmalloc(USER_LIST_SIZE, GFP_ATOMIC);
		if (users) {
			memset(users, 0, USER_LIST_SIZE);
			for (i = 1; i <= MAX_USERID; i++) {
				users[i].next = i - 1;
			}
			next_free_user = MAX_USERID;
		}
	}
	spin_unlock_bh(&reg_lock);
	return users ? TIPC_OK : -ENOMEM;
}

/**
 * reg_callback - inform TIPC user about current operating mode
 */

static void reg_callback(struct tipc_user *user_ptr)
{
	tipc_mode_event cb;
	void *arg;

	spin_lock_bh(&reg_lock);
	cb = user_ptr->callback;
	arg = user_ptr->usr_handle;
	spin_unlock_bh(&reg_lock);

	if (cb)
		cb(arg, tipc_mode, tipc_own_addr);
}

/**
 * reg_start - activate TIPC user registry
 */

int reg_start(void)
{
	u32 u;
	int res;

	if ((res = reg_init()))
		return res;

	for (u = 1; u <= MAX_USERID; u++) {
		if (users[u].callback)
			k_signal((Handler)reg_callback,
				 (unsigned long)&users[u]);
	}
	return TIPC_OK;
}

/**
 * reg_stop - shut down & delete TIPC user registry
 */

void reg_stop(void)
{               
	int id;

	if (!users)
		return;

	for (id = 1; id <= MAX_USERID; id++) {
		if (users[id].callback)
			reg_callback(&users[id]);
	}
	kfree(users);
	users = 0;
}

/**
 * tipc_attach - register a TIPC user
 *
 * NOTE: This routine may be called when TIPC is inactive.
 */

int tipc_attach(u32 *userid, tipc_mode_event cb, void *usr_handle)
{
	struct tipc_user *user_ptr;

	if ((tipc_mode == TIPC_NOT_RUNNING) && !cb)
		return -ENOPROTOOPT;
	if (!users)
		reg_init();

	spin_lock_bh(&reg_lock);
	if (!next_free_user) {
		spin_unlock_bh(&reg_lock);
		return -EBUSY;
	}
	user_ptr = &users[next_free_user];
	*userid = next_free_user;
	next_free_user = user_ptr->next;
	user_ptr->next = -1; 
	spin_unlock_bh(&reg_lock);

	user_ptr->callback = cb;
	user_ptr->usr_handle = usr_handle;
	INIT_LIST_HEAD(&user_ptr->ports);
	atomic_inc(&tipc_user_count);
	
	if (cb && (tipc_mode != TIPC_NOT_RUNNING))
		k_signal((Handler)reg_callback, (unsigned long)user_ptr);
	return TIPC_OK;
}

/**
 * tipc_detach - deregister a TIPC user
 */

void tipc_detach(u32 userid)
{
	struct tipc_user *user_ptr;
	struct list_head ports_temp;
	struct user_port *up_ptr, *temp_up_ptr;

	if ((userid == 0) || (userid > MAX_USERID))
		return;

	spin_lock_bh(&reg_lock);
	if ((!users) || (users[userid].next >= 0)) {
		spin_unlock_bh(&reg_lock);
		return;
	}

	user_ptr = &users[userid];
        user_ptr->callback = NULL;              
	INIT_LIST_HEAD(&ports_temp);
        list_splice(&user_ptr->ports, &ports_temp);
	user_ptr->next = next_free_user;
	next_free_user = userid;
	spin_unlock_bh(&reg_lock);

	atomic_dec(&tipc_user_count);

        list_for_each_entry_safe(up_ptr, temp_up_ptr, &ports_temp, uport_list) {
		tipc_deleteport(up_ptr->ref);
	}
}

/**
 * reg_add_port - register a user's driver port
 */

int reg_add_port(struct user_port *up_ptr)
{
	struct tipc_user *user_ptr;

	if (up_ptr->user_ref == 0)
		return TIPC_OK;
	if (up_ptr->user_ref > MAX_USERID)
		return -EINVAL;
	if ((tipc_mode == TIPC_NOT_RUNNING) || !users )
		return -ENOPROTOOPT;

	spin_lock_bh(&reg_lock);
	user_ptr = &users[up_ptr->user_ref];
	list_add(&up_ptr->uport_list, &user_ptr->ports);
	spin_unlock_bh(&reg_lock);
	return TIPC_OK;
}

/**
 * reg_remove_port - deregister a user's driver port
 */

int reg_remove_port(struct user_port *up_ptr)
{
	if (up_ptr->user_ref == 0)
		return TIPC_OK;
	if (up_ptr->user_ref > MAX_USERID)
		return -EINVAL;
	if (!users )
		return -ENOPROTOOPT;

	spin_lock_bh(&reg_lock);
	list_del_init(&up_ptr->uport_list);
	spin_unlock_bh(&reg_lock);
	return TIPC_OK;
}

OpenPOWER on IntegriCloud