1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 */
6#include <linux/errno.h>
7#include <linux/types.h>
8#include <linux/socket.h>
9#include <linux/in.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/spinlock.h>
13#include <linux/timer.h>
14#include <linux/string.h>
15#include <linux/sockios.h>
16#include <linux/net.h>
17#include <linux/slab.h>
18#include <net/ax25.h>
19#include <linux/inet.h>
20#include <linux/netdevice.h>
21#include <linux/skbuff.h>
22#include <net/sock.h>
23#include <linux/uaccess.h>
24#include <linux/fcntl.h>
25#include <linux/mm.h>
26#include <linux/interrupt.h>
27
28static struct ax25_protocol *protocol_list;
29static DEFINE_RWLOCK(protocol_list_lock);
30
31static HLIST_HEAD(ax25_linkfail_list);
32static DEFINE_SPINLOCK(linkfail_lock);
33
34static struct listen_struct {
35	struct listen_struct *next;
36	ax25_address  callsign;
37	struct net_device *dev;
38} *listen_list = NULL;
39static DEFINE_SPINLOCK(listen_lock);
40
41/*
42 * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
43 * AX25_P_IP or AX25_P_ARP ...
44 */
45void ax25_register_pid(struct ax25_protocol *ap)
46{
47	write_lock_bh(&protocol_list_lock);
48	ap->next = protocol_list;
49	protocol_list = ap;
50	write_unlock_bh(&protocol_list_lock);
51}
52
53EXPORT_SYMBOL_GPL(ax25_register_pid);
54
55void ax25_protocol_release(unsigned int pid)
56{
57	struct ax25_protocol *protocol;
58
59	write_lock_bh(&protocol_list_lock);
60	protocol = protocol_list;
61	if (protocol == NULL)
62		goto out;
63
64	if (protocol->pid == pid) {
65		protocol_list = protocol->next;
66		goto out;
67	}
68
69	while (protocol != NULL && protocol->next != NULL) {
70		if (protocol->next->pid == pid) {
71			protocol->next = protocol->next->next;
72			goto out;
73		}
74
75		protocol = protocol->next;
76	}
77out:
78	write_unlock_bh(&protocol_list_lock);
79}
80
81EXPORT_SYMBOL(ax25_protocol_release);
82
83void ax25_linkfail_register(struct ax25_linkfail *lf)
84{
85	spin_lock_bh(&linkfail_lock);
86	hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
87	spin_unlock_bh(&linkfail_lock);
88}
89
90EXPORT_SYMBOL(ax25_linkfail_register);
91
92void ax25_linkfail_release(struct ax25_linkfail *lf)
93{
94	spin_lock_bh(&linkfail_lock);
95	hlist_del_init(&lf->lf_node);
96	spin_unlock_bh(&linkfail_lock);
97}
98
99EXPORT_SYMBOL(ax25_linkfail_release);
100
101int ax25_listen_register(const ax25_address *callsign, struct net_device *dev)
102{
103	struct listen_struct *listen;
104
105	if (ax25_listen_mine(callsign, dev))
106		return 0;
107
108	if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
109		return -ENOMEM;
110
111	listen->callsign = *callsign;
112	listen->dev      = dev;
113
114	spin_lock_bh(&listen_lock);
115	listen->next = listen_list;
116	listen_list  = listen;
117	spin_unlock_bh(&listen_lock);
118
119	return 0;
120}
121
122EXPORT_SYMBOL(ax25_listen_register);
123
124void ax25_listen_release(const ax25_address *callsign, struct net_device *dev)
125{
126	struct listen_struct *s, *listen;
127
128	spin_lock_bh(&listen_lock);
129	listen = listen_list;
130	if (listen == NULL) {
131		spin_unlock_bh(&listen_lock);
132		return;
133	}
134
135	if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
136		listen_list = listen->next;
137		spin_unlock_bh(&listen_lock);
138		kfree(listen);
139		return;
140	}
141
142	while (listen != NULL && listen->next != NULL) {
143		if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
144			s = listen->next;
145			listen->next = listen->next->next;
146			spin_unlock_bh(&listen_lock);
147			kfree(s);
148			return;
149		}
150
151		listen = listen->next;
152	}
153	spin_unlock_bh(&listen_lock);
154}
155
156EXPORT_SYMBOL(ax25_listen_release);
157
158int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
159{
160	int (*res)(struct sk_buff *, ax25_cb *) = NULL;
161	struct ax25_protocol *protocol;
162
163	read_lock(&protocol_list_lock);
164	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
165		if (protocol->pid == pid) {
166			res = protocol->func;
167			break;
168		}
169	read_unlock(&protocol_list_lock);
170
171	return res;
172}
173
174int ax25_listen_mine(const ax25_address *callsign, struct net_device *dev)
175{
176	struct listen_struct *listen;
177
178	spin_lock_bh(&listen_lock);
179	for (listen = listen_list; listen != NULL; listen = listen->next)
180		if (ax25cmp(&listen->callsign, callsign) == 0 &&
181		    (listen->dev == dev || listen->dev == NULL)) {
182			spin_unlock_bh(&listen_lock);
183			return 1;
184	}
185	spin_unlock_bh(&listen_lock);
186
187	return 0;
188}
189
190void ax25_link_failed(ax25_cb *ax25, int reason)
191{
192	struct ax25_linkfail *lf;
193
194	spin_lock_bh(&linkfail_lock);
195	hlist_for_each_entry(lf, &ax25_linkfail_list, lf_node)
196		lf->func(ax25, reason);
197	spin_unlock_bh(&linkfail_lock);
198}
199
200int ax25_protocol_is_registered(unsigned int pid)
201{
202	struct ax25_protocol *protocol;
203	int res = 0;
204
205	read_lock_bh(&protocol_list_lock);
206	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
207		if (protocol->pid == pid) {
208			res = 1;
209			break;
210		}
211	read_unlock_bh(&protocol_list_lock);
212
213	return res;
214}
215