hdlc_x25.c revision 4dfce4075aa4e2eee35e52a78dbabfe37d94c908 
1/*
2 * Generic HDLC support routines for Linux
3 * X.25 support
4 *
5 * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of version 2 of the GNU General Public License
9 * as published by the Free Software Foundation.
10 */
11
12#include <linux/errno.h>
13#include <linux/hdlc.h>
14#include <linux/if_arp.h>
15#include <linux/inetdevice.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/lapb.h>
19#include <linux/module.h>
20#include <linux/pkt_sched.h>
21#include <linux/poll.h>
22#include <linux/rtnetlink.h>
23#include <linux/skbuff.h>
24#include <linux/slab.h>
25#include <net/x25device.h>
26
27static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
28
29/* These functions are callbacks called by LAPB layer */
30
31static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
32{
33	struct sk_buff *skb;
34	unsigned char *ptr;
35
36	if ((skb = dev_alloc_skb(1)) == NULL) {
37		printk(KERN_ERR "%s: out of memory\n", dev->name);
38		return;
39	}
40
41	ptr = skb_put(skb, 1);
42	*ptr = code;
43
44	skb->protocol = x25_type_trans(skb, dev);
45	netif_rx(skb);
46}
47
48
49
50static void x25_connected(struct net_device *dev, int reason)
51{
52	x25_connect_disconnect(dev, reason, 1);
53}
54
55
56
57static void x25_disconnected(struct net_device *dev, int reason)
58{
59	x25_connect_disconnect(dev, reason, 2);
60}
61
62
63
64static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
65{
66	unsigned char *ptr;
67
68	skb_push(skb, 1);
69
70	if (skb_cow(skb, 1))
71		return NET_RX_DROP;
72
73	ptr  = skb->data;
74	*ptr = 0;
75
76	skb->protocol = x25_type_trans(skb, dev);
77	return netif_rx(skb);
78}
79
80
81
82static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
83{
84	hdlc_device *hdlc = dev_to_hdlc(dev);
85	hdlc->xmit(skb, dev); /* Ignore return value :-( */
86}
87
88
89
90static int x25_xmit(struct sk_buff *skb, struct net_device *dev)
91{
92	int result;
93
94
95	/* X.25 to LAPB */
96	switch (skb->data[0]) {
97	case 0:		/* Data to be transmitted */
98		skb_pull(skb, 1);
99		if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
100			dev_kfree_skb(skb);
101		return 0;
102
103	case 1:
104		if ((result = lapb_connect_request(dev))!= LAPB_OK) {
105			if (result == LAPB_CONNECTED)
106				/* Send connect confirm. msg to level 3 */
107				x25_connected(dev, 0);
108			else
109				printk(KERN_ERR "%s: LAPB connect request "
110				       "failed, error code = %i\n",
111				       dev->name, result);
112		}
113		break;
114
115	case 2:
116		if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
117			if (result == LAPB_NOTCONNECTED)
118				/* Send disconnect confirm. msg to level 3 */
119				x25_disconnected(dev, 0);
120			else
121				printk(KERN_ERR "%s: LAPB disconnect request "
122				       "failed, error code = %i\n",
123				       dev->name, result);
124		}
125		break;
126
127	default:		/* to be defined */
128		break;
129	}
130
131	dev_kfree_skb(skb);
132	return 0;
133}
134
135
136
137static int x25_open(struct net_device *dev)
138{
139	struct lapb_register_struct cb;
140	int result;
141
142	cb.connect_confirmation = x25_connected;
143	cb.connect_indication = x25_connected;
144	cb.disconnect_confirmation = x25_disconnected;
145	cb.disconnect_indication = x25_disconnected;
146	cb.data_indication = x25_data_indication;
147	cb.data_transmit = x25_data_transmit;
148
149	result = lapb_register(dev, &cb);
150	if (result != LAPB_OK)
151		return result;
152	return 0;
153}
154
155
156
157static void x25_close(struct net_device *dev)
158{
159	lapb_unregister(dev);
160}
161
162
163
164static int x25_rx(struct sk_buff *skb)
165{
166	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
167		skb->dev->stats.rx_dropped++;
168		return NET_RX_DROP;
169	}
170
171	if (lapb_data_received(skb->dev, skb) == LAPB_OK)
172		return NET_RX_SUCCESS;
173
174	skb->dev->stats.rx_errors++;
175	dev_kfree_skb_any(skb);
176	return NET_RX_DROP;
177}
178
179
180static struct hdlc_proto proto = {
181	.open		= x25_open,
182	.close		= x25_close,
183	.ioctl		= x25_ioctl,
184	.netif_rx	= x25_rx,
185	.module		= THIS_MODULE,
186};
187
188
189static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
190{
191	hdlc_device *hdlc = dev_to_hdlc(dev);
192	int result;
193
194	switch (ifr->ifr_settings.type) {
195	case IF_GET_PROTO:
196		if (dev_to_hdlc(dev)->proto != &proto)
197			return -EINVAL;
198		ifr->ifr_settings.type = IF_PROTO_X25;
199		return 0; /* return protocol only, no settable parameters */
200
201	case IF_PROTO_X25:
202		if(!capable(CAP_NET_ADMIN))
203			return -EPERM;
204
205		if(dev->flags & IFF_UP)
206			return -EBUSY;
207
208		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
209		if (result)
210			return result;
211
212		if ((result = attach_hdlc_protocol(dev, &proto, 0)))
213			return result;
214		dev->hard_start_xmit = x25_xmit;
215		dev->type = ARPHRD_X25;
216		netif_dormant_off(dev);
217		return 0;
218	}
219
220	return -EINVAL;
221}
222
223
224static int __init mod_init(void)
225{
226	register_hdlc_protocol(&proto);
227	return 0;
228}
229
230
231
232static void __exit mod_exit(void)
233{
234	unregister_hdlc_protocol(&proto);
235}
236
237
238module_init(mod_init);
239module_exit(mod_exit);
240
241MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
242MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
243MODULE_LICENSE("GPL v2");
244