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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/slab.h>
10 #include <linux/in.h>
11 #include <linux/kernel.h>
12 #include <linux/timer.h>
13 #include <linux/string.h>
14 #include <linux/sockios.h>
15 #include <linux/net.h>
16 #include <linux/spinlock.h>
17 #include <net/ax25.h>
18 #include <linux/inet.h>
19 #include <linux/netdevice.h>
20 #include <linux/if_arp.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 #include <linux/init.h>
28 
29 ax25_dev *ax25_dev_list;
30 DEFINE_SPINLOCK(ax25_dev_lock);
31 
ax25_addr_ax25dev(ax25_address * addr)32 ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
33 {
34 	ax25_dev *ax25_dev, *res = NULL;
35 
36 	spin_lock_bh(&ax25_dev_lock);
37 	for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
38 		if (ax25cmp(addr, (ax25_address *)ax25_dev->dev->dev_addr) == 0) {
39 			res = ax25_dev;
40 			ax25_dev_hold(ax25_dev);
41 		}
42 	spin_unlock_bh(&ax25_dev_lock);
43 
44 	return res;
45 }
46 
47 /*
48  *	This is called when an interface is brought up. These are
49  *	reasonable defaults.
50  */
ax25_dev_device_up(struct net_device * dev)51 void ax25_dev_device_up(struct net_device *dev)
52 {
53 	ax25_dev *ax25_dev;
54 
55 	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
56 		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
57 		return;
58 	}
59 
60 	refcount_set(&ax25_dev->refcount, 1);
61 	dev->ax25_ptr     = ax25_dev;
62 	ax25_dev->dev     = dev;
63 	dev_hold(dev);
64 	ax25_dev->forward = NULL;
65 
66 	ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
67 	ax25_dev->values[AX25_VALUES_AXDEFMODE] = AX25_DEF_AXDEFMODE;
68 	ax25_dev->values[AX25_VALUES_BACKOFF]   = AX25_DEF_BACKOFF;
69 	ax25_dev->values[AX25_VALUES_CONMODE]   = AX25_DEF_CONMODE;
70 	ax25_dev->values[AX25_VALUES_WINDOW]    = AX25_DEF_WINDOW;
71 	ax25_dev->values[AX25_VALUES_EWINDOW]   = AX25_DEF_EWINDOW;
72 	ax25_dev->values[AX25_VALUES_T1]        = AX25_DEF_T1;
73 	ax25_dev->values[AX25_VALUES_T2]        = AX25_DEF_T2;
74 	ax25_dev->values[AX25_VALUES_T3]        = AX25_DEF_T3;
75 	ax25_dev->values[AX25_VALUES_IDLE]	= AX25_DEF_IDLE;
76 	ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
77 	ax25_dev->values[AX25_VALUES_PACLEN]	= AX25_DEF_PACLEN;
78 	ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
79 	ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
80 
81 #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
82 	ax25_ds_setup_timer(ax25_dev);
83 #endif
84 
85 	spin_lock_bh(&ax25_dev_lock);
86 	ax25_dev->next = ax25_dev_list;
87 	ax25_dev_list  = ax25_dev;
88 	spin_unlock_bh(&ax25_dev_lock);
89 	ax25_dev_hold(ax25_dev);
90 
91 	ax25_register_dev_sysctl(ax25_dev);
92 }
93 
ax25_dev_device_down(struct net_device * dev)94 void ax25_dev_device_down(struct net_device *dev)
95 {
96 	ax25_dev *s, *ax25_dev;
97 
98 	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
99 		return;
100 
101 	ax25_unregister_dev_sysctl(ax25_dev);
102 
103 	spin_lock_bh(&ax25_dev_lock);
104 
105 #ifdef CONFIG_AX25_DAMA_SLAVE
106 	ax25_ds_del_timer(ax25_dev);
107 #endif
108 
109 	/*
110 	 *	Remove any packet forwarding that points to this device.
111 	 */
112 	for (s = ax25_dev_list; s != NULL; s = s->next)
113 		if (s->forward == dev)
114 			s->forward = NULL;
115 
116 	if ((s = ax25_dev_list) == ax25_dev) {
117 		ax25_dev_list = s->next;
118 		spin_unlock_bh(&ax25_dev_lock);
119 		ax25_dev_put(ax25_dev);
120 		dev->ax25_ptr = NULL;
121 		dev_put(dev);
122 		ax25_dev_put(ax25_dev);
123 		return;
124 	}
125 
126 	while (s != NULL && s->next != NULL) {
127 		if (s->next == ax25_dev) {
128 			s->next = ax25_dev->next;
129 			spin_unlock_bh(&ax25_dev_lock);
130 			ax25_dev_put(ax25_dev);
131 			dev->ax25_ptr = NULL;
132 			dev_put(dev);
133 			ax25_dev_put(ax25_dev);
134 			return;
135 		}
136 
137 		s = s->next;
138 	}
139 	spin_unlock_bh(&ax25_dev_lock);
140 	dev->ax25_ptr = NULL;
141 	ax25_dev_put(ax25_dev);
142 }
143 
ax25_fwd_ioctl(unsigned int cmd,struct ax25_fwd_struct * fwd)144 int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
145 {
146 	ax25_dev *ax25_dev, *fwd_dev;
147 
148 	if ((ax25_dev = ax25_addr_ax25dev(&fwd->port_from)) == NULL)
149 		return -EINVAL;
150 
151 	switch (cmd) {
152 	case SIOCAX25ADDFWD:
153 		fwd_dev = ax25_addr_ax25dev(&fwd->port_to);
154 		if (!fwd_dev) {
155 			ax25_dev_put(ax25_dev);
156 			return -EINVAL;
157 		}
158 		if (ax25_dev->forward) {
159 			ax25_dev_put(fwd_dev);
160 			ax25_dev_put(ax25_dev);
161 			return -EINVAL;
162 		}
163 		ax25_dev->forward = fwd_dev->dev;
164 		ax25_dev_put(fwd_dev);
165 		ax25_dev_put(ax25_dev);
166 		break;
167 
168 	case SIOCAX25DELFWD:
169 		if (!ax25_dev->forward) {
170 			ax25_dev_put(ax25_dev);
171 			return -EINVAL;
172 		}
173 		ax25_dev->forward = NULL;
174 		ax25_dev_put(ax25_dev);
175 		break;
176 
177 	default:
178 		ax25_dev_put(ax25_dev);
179 		return -EINVAL;
180 	}
181 
182 	return 0;
183 }
184 
ax25_fwd_dev(struct net_device * dev)185 struct net_device *ax25_fwd_dev(struct net_device *dev)
186 {
187 	ax25_dev *ax25_dev;
188 
189 	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
190 		return dev;
191 
192 	if (ax25_dev->forward == NULL)
193 		return dev;
194 
195 	return ax25_dev->forward;
196 }
197 
198 /*
199  *	Free all memory associated with device structures.
200  */
ax25_dev_free(void)201 void __exit ax25_dev_free(void)
202 {
203 	ax25_dev *s, *ax25_dev;
204 
205 	spin_lock_bh(&ax25_dev_lock);
206 	ax25_dev = ax25_dev_list;
207 	while (ax25_dev != NULL) {
208 		s        = ax25_dev;
209 		dev_put(ax25_dev->dev);
210 		ax25_dev = ax25_dev->next;
211 		kfree(s);
212 	}
213 	ax25_dev_list = NULL;
214 	spin_unlock_bh(&ax25_dev_lock);
215 }
216