1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 */
9#include <linux/errno.h>
10#include <linux/types.h>
11#include <linux/socket.h>
12#include <linux/in.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/spinlock.h>
16#include <linux/timer.h>
17#include <linux/string.h>
18#include <linux/sockios.h>
19#include <linux/net.h>
20#include <linux/slab.h>
21#include <net/ax25.h>
22#include <linux/inet.h>
23#include <linux/netdevice.h>
24#include <linux/skbuff.h>
25#include <net/sock.h>
26#include <asm/uaccess.h>
27#include <asm/system.h>
28#include <linux/fcntl.h>
29#include <linux/mm.h>
30#include <linux/interrupt.h>
31
32static struct ax25_protocol *protocol_list;
33static DEFINE_RWLOCK(protocol_list_lock);
34
35static HLIST_HEAD(ax25_linkfail_list);
36static DEFINE_SPINLOCK(linkfail_lock);
37
38static struct listen_struct {
39	struct listen_struct *next;
40	ax25_address  callsign;
41	struct net_device *dev;
42} *listen_list = NULL;
43static DEFINE_SPINLOCK(listen_lock);
44
45/*
46 * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
47 * AX25_P_IP or AX25_P_ARP ...
48 */
49void ax25_register_pid(struct ax25_protocol *ap)
50{
51	write_lock_bh(&protocol_list_lock);
52	ap->next = protocol_list;
53	protocol_list = ap;
54	write_unlock_bh(&protocol_list_lock);
55}
56
57EXPORT_SYMBOL_GPL(ax25_register_pid);
58
59void ax25_protocol_release(unsigned int pid)
60{
61	struct ax25_protocol *s, *protocol;
62
63	write_lock_bh(&protocol_list_lock);
64	protocol = protocol_list;
65	if (protocol == NULL)
66		goto out;
67
68	if (protocol->pid == pid) {
69		protocol_list = protocol->next;
70		goto out;
71	}
72
73	while (protocol != NULL && protocol->next != NULL) {
74		if (protocol->next->pid == pid) {
75			s = protocol->next;
76			protocol->next = protocol->next->next;
77			goto out;
78		}
79
80		protocol = protocol->next;
81	}
82out:
83	write_unlock_bh(&protocol_list_lock);
84}
85
86EXPORT_SYMBOL(ax25_protocol_release);
87
88void ax25_linkfail_register(struct ax25_linkfail *lf)
89{
90	spin_lock_bh(&linkfail_lock);
91	hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
92	spin_unlock_bh(&linkfail_lock);
93}
94
95EXPORT_SYMBOL(ax25_linkfail_register);
96
97void ax25_linkfail_release(struct ax25_linkfail *lf)
98{
99	spin_lock_bh(&linkfail_lock);
100	hlist_del_init(&lf->lf_node);
101	spin_unlock_bh(&linkfail_lock);
102}
103
104EXPORT_SYMBOL(ax25_linkfail_release);
105
106int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
107{
108	struct listen_struct *listen;
109
110	if (ax25_listen_mine(callsign, dev))
111		return 0;
112
113	if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
114		return -ENOMEM;
115
116	listen->callsign = *callsign;
117	listen->dev      = dev;
118
119	spin_lock_bh(&listen_lock);
120	listen->next = listen_list;
121	listen_list  = listen;
122	spin_unlock_bh(&listen_lock);
123
124	return 0;
125}
126
127EXPORT_SYMBOL(ax25_listen_register);
128
129void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
130{
131	struct listen_struct *s, *listen;
132
133	spin_lock_bh(&listen_lock);
134	listen = listen_list;
135	if (listen == NULL) {
136		spin_unlock_bh(&listen_lock);
137		return;
138	}
139
140	if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
141		listen_list = listen->next;
142		spin_unlock_bh(&listen_lock);
143		kfree(listen);
144		return;
145	}
146
147	while (listen != NULL && listen->next != NULL) {
148		if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
149			s = listen->next;
150			listen->next = listen->next->next;
151			spin_unlock_bh(&listen_lock);
152			kfree(s);
153			return;
154		}
155
156		listen = listen->next;
157	}
158	spin_unlock_bh(&listen_lock);
159}
160
161EXPORT_SYMBOL(ax25_listen_release);
162
163int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
164{
165	int (*res)(struct sk_buff *, ax25_cb *) = NULL;
166	struct ax25_protocol *protocol;
167
168	read_lock(&protocol_list_lock);
169	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
170		if (protocol->pid == pid) {
171			res = protocol->func;
172			break;
173		}
174	read_unlock(&protocol_list_lock);
175
176	return res;
177}
178
179int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
180{
181	struct listen_struct *listen;
182
183	spin_lock_bh(&listen_lock);
184	for (listen = listen_list; listen != NULL; listen = listen->next)
185		if (ax25cmp(&listen->callsign, callsign) == 0 &&
186		    (listen->dev == dev || listen->dev == NULL)) {
187			spin_unlock_bh(&listen_lock);
188			return 1;
189	}
190	spin_unlock_bh(&listen_lock);
191
192	return 0;
193}
194
195void ax25_link_failed(ax25_cb *ax25, int reason)
196{
197	struct ax25_linkfail *lf;
198	struct hlist_node *node;
199
200	spin_lock_bh(&linkfail_lock);
201	hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
202		lf->func(ax25, reason);
203	spin_unlock_bh(&linkfail_lock);
204}
205
206int ax25_protocol_is_registered(unsigned int pid)
207{
208	struct ax25_protocol *protocol;
209	int res = 0;
210
211	read_lock_bh(&protocol_list_lock);
212	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
213		if (protocol->pid == pid) {
214			res = 1;
215			break;
216		}
217	read_unlock_bh(&protocol_list_lock);
218
219	return res;
220}
221