1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Generic HDLC support routines for Linux
4 * X.25 support
5 *
6 * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
7 */
8
9 #include <linux/errno.h>
10 #include <linux/gfp.h>
11 #include <linux/hdlc.h>
12 #include <linux/if_arp.h>
13 #include <linux/inetdevice.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/lapb.h>
17 #include <linux/module.h>
18 #include <linux/pkt_sched.h>
19 #include <linux/poll.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/skbuff.h>
22 #include <net/x25device.h>
23
24 struct x25_state {
25 x25_hdlc_proto settings;
26 };
27
28 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
29
state(hdlc_device * hdlc)30 static struct x25_state *state(hdlc_device *hdlc)
31 {
32 return hdlc->state;
33 }
34
35 /* These functions are callbacks called by LAPB layer */
36
x25_connect_disconnect(struct net_device * dev,int reason,int code)37 static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
38 {
39 struct sk_buff *skb;
40 unsigned char *ptr;
41
42 if ((skb = dev_alloc_skb(1)) == NULL) {
43 netdev_err(dev, "out of memory\n");
44 return;
45 }
46
47 ptr = skb_put(skb, 1);
48 *ptr = code;
49
50 skb->protocol = x25_type_trans(skb, dev);
51 netif_rx(skb);
52 }
53
54
55
x25_connected(struct net_device * dev,int reason)56 static void x25_connected(struct net_device *dev, int reason)
57 {
58 x25_connect_disconnect(dev, reason, X25_IFACE_CONNECT);
59 }
60
61
62
x25_disconnected(struct net_device * dev,int reason)63 static void x25_disconnected(struct net_device *dev, int reason)
64 {
65 x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
66 }
67
68
69
x25_data_indication(struct net_device * dev,struct sk_buff * skb)70 static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
71 {
72 unsigned char *ptr;
73
74 if (skb_cow(skb, 1)) {
75 kfree_skb(skb);
76 return NET_RX_DROP;
77 }
78
79 skb_push(skb, 1);
80 skb_reset_network_header(skb);
81
82 ptr = skb->data;
83 *ptr = X25_IFACE_DATA;
84
85 skb->protocol = x25_type_trans(skb, dev);
86 return netif_rx(skb);
87 }
88
89
90
x25_data_transmit(struct net_device * dev,struct sk_buff * skb)91 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
92 {
93 hdlc_device *hdlc = dev_to_hdlc(dev);
94
95 skb_reset_network_header(skb);
96 skb->protocol = hdlc_type_trans(skb, dev);
97
98 if (dev_nit_active(dev))
99 dev_queue_xmit_nit(skb, dev);
100
101 hdlc->xmit(skb, dev); /* Ignore return value :-( */
102 }
103
104
105
x25_xmit(struct sk_buff * skb,struct net_device * dev)106 static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
107 {
108 int result;
109
110 /* There should be a pseudo header of 1 byte added by upper layers.
111 * Check to make sure it is there before reading it.
112 */
113 if (skb->len < 1) {
114 kfree_skb(skb);
115 return NETDEV_TX_OK;
116 }
117
118 switch (skb->data[0]) {
119 case X25_IFACE_DATA: /* Data to be transmitted */
120 skb_pull(skb, 1);
121 skb_reset_network_header(skb);
122 if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
123 dev_kfree_skb(skb);
124 return NETDEV_TX_OK;
125
126 case X25_IFACE_CONNECT:
127 if ((result = lapb_connect_request(dev))!= LAPB_OK) {
128 if (result == LAPB_CONNECTED)
129 /* Send connect confirm. msg to level 3 */
130 x25_connected(dev, 0);
131 else
132 netdev_err(dev, "LAPB connect request failed, error code = %i\n",
133 result);
134 }
135 break;
136
137 case X25_IFACE_DISCONNECT:
138 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
139 if (result == LAPB_NOTCONNECTED)
140 /* Send disconnect confirm. msg to level 3 */
141 x25_disconnected(dev, 0);
142 else
143 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
144 result);
145 }
146 break;
147
148 default: /* to be defined */
149 break;
150 }
151
152 dev_kfree_skb(skb);
153 return NETDEV_TX_OK;
154 }
155
156
157
x25_open(struct net_device * dev)158 static int x25_open(struct net_device *dev)
159 {
160 static const struct lapb_register_struct cb = {
161 .connect_confirmation = x25_connected,
162 .connect_indication = x25_connected,
163 .disconnect_confirmation = x25_disconnected,
164 .disconnect_indication = x25_disconnected,
165 .data_indication = x25_data_indication,
166 .data_transmit = x25_data_transmit,
167 };
168 hdlc_device *hdlc = dev_to_hdlc(dev);
169 struct lapb_parms_struct params;
170 int result;
171
172 result = lapb_register(dev, &cb);
173 if (result != LAPB_OK)
174 return result;
175
176 result = lapb_getparms(dev, ¶ms);
177 if (result != LAPB_OK)
178 return result;
179
180 if (state(hdlc)->settings.dce)
181 params.mode = params.mode | LAPB_DCE;
182
183 if (state(hdlc)->settings.modulo == 128)
184 params.mode = params.mode | LAPB_EXTENDED;
185
186 params.window = state(hdlc)->settings.window;
187 params.t1 = state(hdlc)->settings.t1;
188 params.t2 = state(hdlc)->settings.t2;
189 params.n2 = state(hdlc)->settings.n2;
190
191 result = lapb_setparms(dev, ¶ms);
192 if (result != LAPB_OK)
193 return result;
194
195 return 0;
196 }
197
198
199
x25_close(struct net_device * dev)200 static void x25_close(struct net_device *dev)
201 {
202 lapb_unregister(dev);
203 }
204
205
206
x25_rx(struct sk_buff * skb)207 static int x25_rx(struct sk_buff *skb)
208 {
209 struct net_device *dev = skb->dev;
210
211 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
212 dev->stats.rx_dropped++;
213 return NET_RX_DROP;
214 }
215
216 if (lapb_data_received(dev, skb) == LAPB_OK)
217 return NET_RX_SUCCESS;
218
219 dev->stats.rx_errors++;
220 dev_kfree_skb_any(skb);
221 return NET_RX_DROP;
222 }
223
224
225 static struct hdlc_proto proto = {
226 .open = x25_open,
227 .close = x25_close,
228 .ioctl = x25_ioctl,
229 .netif_rx = x25_rx,
230 .xmit = x25_xmit,
231 .module = THIS_MODULE,
232 };
233
234
x25_ioctl(struct net_device * dev,struct ifreq * ifr)235 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
236 {
237 x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
238 const size_t size = sizeof(x25_hdlc_proto);
239 hdlc_device *hdlc = dev_to_hdlc(dev);
240 x25_hdlc_proto new_settings;
241 int result;
242
243 switch (ifr->ifr_settings.type) {
244 case IF_GET_PROTO:
245 if (dev_to_hdlc(dev)->proto != &proto)
246 return -EINVAL;
247 ifr->ifr_settings.type = IF_PROTO_X25;
248 if (ifr->ifr_settings.size < size) {
249 ifr->ifr_settings.size = size; /* data size wanted */
250 return -ENOBUFS;
251 }
252 if (copy_to_user(x25_s, &state(hdlc)->settings, size))
253 return -EFAULT;
254 return 0;
255
256 case IF_PROTO_X25:
257 if (!capable(CAP_NET_ADMIN))
258 return -EPERM;
259
260 if (dev->flags & IFF_UP)
261 return -EBUSY;
262
263 /* backward compatibility */
264 if (ifr->ifr_settings.size == 0) {
265 new_settings.dce = 0;
266 new_settings.modulo = 8;
267 new_settings.window = 7;
268 new_settings.t1 = 3;
269 new_settings.t2 = 1;
270 new_settings.n2 = 10;
271 }
272 else {
273 if (copy_from_user(&new_settings, x25_s, size))
274 return -EFAULT;
275
276 if ((new_settings.dce != 0 &&
277 new_settings.dce != 1) ||
278 (new_settings.modulo != 8 &&
279 new_settings.modulo != 128) ||
280 new_settings.window < 1 ||
281 (new_settings.modulo == 8 &&
282 new_settings.window > 7) ||
283 (new_settings.modulo == 128 &&
284 new_settings.window > 127) ||
285 new_settings.t1 < 1 ||
286 new_settings.t1 > 255 ||
287 new_settings.t2 < 1 ||
288 new_settings.t2 > 255 ||
289 new_settings.n2 < 1 ||
290 new_settings.n2 > 255)
291 return -EINVAL;
292 }
293
294 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
295 if (result)
296 return result;
297
298 if ((result = attach_hdlc_protocol(dev, &proto,
299 sizeof(struct x25_state))))
300 return result;
301
302 memcpy(&state(hdlc)->settings, &new_settings, size);
303
304 /* There's no header_ops so hard_header_len should be 0. */
305 dev->hard_header_len = 0;
306 /* When transmitting data:
307 * first we'll remove a pseudo header of 1 byte,
308 * then we'll prepend an LAPB header of at most 3 bytes.
309 */
310 dev->needed_headroom = 3 - 1;
311
312 dev->type = ARPHRD_X25;
313 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
314 netif_dormant_off(dev);
315 return 0;
316 }
317
318 return -EINVAL;
319 }
320
321
mod_init(void)322 static int __init mod_init(void)
323 {
324 register_hdlc_protocol(&proto);
325 return 0;
326 }
327
328
329
mod_exit(void)330 static void __exit mod_exit(void)
331 {
332 unregister_hdlc_protocol(&proto);
333 }
334
335
336 module_init(mod_init);
337 module_exit(mod_exit);
338
339 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
340 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
341 MODULE_LICENSE("GPL v2");
342