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 
31 static struct ax25_protocol *protocol_list;
32 static DEFINE_RWLOCK(protocol_list_lock);
33 
34 static HLIST_HEAD(ax25_linkfail_list);
35 static DEFINE_SPINLOCK(linkfail_lock);
36 
37 static struct listen_struct {
38 	struct listen_struct *next;
39 	ax25_address  callsign;
40 	struct net_device *dev;
41 } *listen_list = NULL;
42 static 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  */
ax25_register_pid(struct ax25_protocol * ap)48 void 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 
56 EXPORT_SYMBOL_GPL(ax25_register_pid);
57 
ax25_protocol_release(unsigned int pid)58 void 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 	}
80 out:
81 	write_unlock_bh(&protocol_list_lock);
82 }
83 
84 EXPORT_SYMBOL(ax25_protocol_release);
85 
ax25_linkfail_register(struct ax25_linkfail * lf)86 void 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 
93 EXPORT_SYMBOL(ax25_linkfail_register);
94 
ax25_linkfail_release(struct ax25_linkfail * lf)95 void 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 
102 EXPORT_SYMBOL(ax25_linkfail_release);
103 
ax25_listen_register(ax25_address * callsign,struct net_device * dev)104 int 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 
125 EXPORT_SYMBOL(ax25_listen_register);
126 
ax25_listen_release(ax25_address * callsign,struct net_device * dev)127 void 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 
159 EXPORT_SYMBOL(ax25_listen_release);
160 
ax25_protocol_function(unsigned int pid)161 int (*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 
ax25_listen_mine(ax25_address * callsign,struct net_device * dev)177 int 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 
ax25_link_failed(ax25_cb * ax25,int reason)193 void ax25_link_failed(ax25_cb *ax25, int reason)
194 {
195 	struct ax25_linkfail *lf;
196 	struct hlist_node *node;
197 
198 	spin_lock_bh(&linkfail_lock);
199 	hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
200 		lf->func(ax25, reason);
201 	spin_unlock_bh(&linkfail_lock);
202 }
203 
ax25_protocol_is_registered(unsigned int pid)204 int ax25_protocol_is_registered(unsigned int pid)
205 {
206 	struct ax25_protocol *protocol;
207 	int res = 0;
208 
209 	read_lock_bh(&protocol_list_lock);
210 	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
211 		if (protocol->pid == pid) {
212 			res = 1;
213 			break;
214 		}
215 	read_unlock_bh(&protocol_list_lock);
216 
217 	return res;
218 }
219