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 
28 static struct ax25_protocol *protocol_list;
29 static DEFINE_RWLOCK(protocol_list_lock);
30 
31 static HLIST_HEAD(ax25_linkfail_list);
32 static DEFINE_SPINLOCK(linkfail_lock);
33 
34 static struct listen_struct {
35 	struct listen_struct *next;
36 	ax25_address  callsign;
37 	struct net_device *dev;
38 } *listen_list = NULL;
39 static 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  */
ax25_register_pid(struct ax25_protocol * ap)45 void 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 
53 EXPORT_SYMBOL_GPL(ax25_register_pid);
54 
ax25_protocol_release(unsigned int pid)55 void 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 	}
77 out:
78 	write_unlock_bh(&protocol_list_lock);
79 }
80 
81 EXPORT_SYMBOL(ax25_protocol_release);
82 
ax25_linkfail_register(struct ax25_linkfail * lf)83 void 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 
90 EXPORT_SYMBOL(ax25_linkfail_register);
91 
ax25_linkfail_release(struct ax25_linkfail * lf)92 void 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 
99 EXPORT_SYMBOL(ax25_linkfail_release);
100 
ax25_listen_register(const ax25_address * callsign,struct net_device * dev)101 int 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 
122 EXPORT_SYMBOL(ax25_listen_register);
123 
ax25_listen_release(const ax25_address * callsign,struct net_device * dev)124 void 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 
156 EXPORT_SYMBOL(ax25_listen_release);
157 
ax25_protocol_function(unsigned int pid)158 int (*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 
ax25_listen_mine(const ax25_address * callsign,struct net_device * dev)174 int 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 
ax25_link_failed(ax25_cb * ax25,int reason)190 void 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 
ax25_protocol_is_registered(unsigned int pid)200 int 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