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 <linux/fcntl.h>
28#include <linux/mm.h>
29#include <linux/interrupt.h>
30
31static struct ax25_protocol *protocol_list;
32static DEFINE_RWLOCK(protocol_list_lock);
33
34static HLIST_HEAD(ax25_linkfail_list);
35static DEFINE_SPINLOCK(linkfail_lock);
36
37static struct listen_struct {
38	struct listen_struct *next;
39	ax25_address  callsign;
40	struct net_device *dev;
41} *listen_list = NULL;
42static DEFINE_SPINLOCK(listen_lock);
43
44/*
45 * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
46 * AX25_P_IP or AX25_P_ARP ...
47 */
48void ax25_register_pid(struct ax25_protocol *ap)
49{
50	write_lock_bh(&protocol_list_lock);
51	ap->next = protocol_list;
52	protocol_list = ap;
53	write_unlock_bh(&protocol_list_lock);
54}
55
56EXPORT_SYMBOL_GPL(ax25_register_pid);
57
58void ax25_protocol_release(unsigned int pid)
59{
60	struct ax25_protocol *protocol;
61
62	write_lock_bh(&protocol_list_lock);
63	protocol = protocol_list;
64	if (protocol == NULL)
65		goto out;
66
67	if (protocol->pid == pid) {
68		protocol_list = protocol->next;
69		goto out;
70	}
71
72	while (protocol != NULL && protocol->next != NULL) {
73		if (protocol->next->pid == pid) {
74			protocol->next = protocol->next->next;
75			goto out;
76		}
77
78		protocol = protocol->next;
79	}
80out:
81	write_unlock_bh(&protocol_list_lock);
82}
83
84EXPORT_SYMBOL(ax25_protocol_release);
85
86void ax25_linkfail_register(struct ax25_linkfail *lf)
87{
88	spin_lock_bh(&linkfail_lock);
89	hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
90	spin_unlock_bh(&linkfail_lock);
91}
92
93EXPORT_SYMBOL(ax25_linkfail_register);
94
95void ax25_linkfail_release(struct ax25_linkfail *lf)
96{
97	spin_lock_bh(&linkfail_lock);
98	hlist_del_init(&lf->lf_node);
99	spin_unlock_bh(&linkfail_lock);
100}
101
102EXPORT_SYMBOL(ax25_linkfail_release);
103
104int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
105{
106	struct listen_struct *listen;
107
108	if (ax25_listen_mine(callsign, dev))
109		return 0;
110
111	if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
112		return -ENOMEM;
113
114	listen->callsign = *callsign;
115	listen->dev      = dev;
116
117	spin_lock_bh(&listen_lock);
118	listen->next = listen_list;
119	listen_list  = listen;
120	spin_unlock_bh(&listen_lock);
121
122	return 0;
123}
124
125EXPORT_SYMBOL(ax25_listen_register);
126
127void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
128{
129	struct listen_struct *s, *listen;
130
131	spin_lock_bh(&listen_lock);
132	listen = listen_list;
133	if (listen == NULL) {
134		spin_unlock_bh(&listen_lock);
135		return;
136	}
137
138	if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
139		listen_list = listen->next;
140		spin_unlock_bh(&listen_lock);
141		kfree(listen);
142		return;
143	}
144
145	while (listen != NULL && listen->next != NULL) {
146		if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
147			s = listen->next;
148			listen->next = listen->next->next;
149			spin_unlock_bh(&listen_lock);
150			kfree(s);
151			return;
152		}
153
154		listen = listen->next;
155	}
156	spin_unlock_bh(&listen_lock);
157}
158
159EXPORT_SYMBOL(ax25_listen_release);
160
161int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
162{
163	int (*res)(struct sk_buff *, ax25_cb *) = NULL;
164	struct ax25_protocol *protocol;
165
166	read_lock(&protocol_list_lock);
167	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
168		if (protocol->pid == pid) {
169			res = protocol->func;
170			break;
171		}
172	read_unlock(&protocol_list_lock);
173
174	return res;
175}
176
177int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
178{
179	struct listen_struct *listen;
180
181	spin_lock_bh(&listen_lock);
182	for (listen = listen_list; listen != NULL; listen = listen->next)
183		if (ax25cmp(&listen->callsign, callsign) == 0 &&
184		    (listen->dev == dev || listen->dev == NULL)) {
185			spin_unlock_bh(&listen_lock);
186			return 1;
187	}
188	spin_unlock_bh(&listen_lock);
189
190	return 0;
191}
192
193void ax25_link_failed(ax25_cb *ax25, int reason)
194{
195	struct ax25_linkfail *lf;
196
197	spin_lock_bh(&linkfail_lock);
198	hlist_for_each_entry(lf, &ax25_linkfail_list, lf_node)
199		lf->func(ax25, reason);
200	spin_unlock_bh(&linkfail_lock);
201}
202
203int ax25_protocol_is_registered(unsigned int pid)
204{
205	struct ax25_protocol *protocol;
206	int res = 0;
207
208	read_lock_bh(&protocol_list_lock);
209	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
210		if (protocol->pid == pid) {
211			res = 1;
212			break;
213		}
214	read_unlock_bh(&protocol_list_lock);
215
216	return res;
217}
218