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/gfp.h>
14#include <linux/hdlc.h>
15#include <linux/if_arp.h>
16#include <linux/inetdevice.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/lapb.h>
20#include <linux/module.h>
21#include <linux/pkt_sched.h>
22#include <linux/poll.h>
23#include <linux/rtnetlink.h>
24#include <linux/skbuff.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		netdev_err(dev, "out of memory\n");
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, X25_IFACE_CONNECT);
53}
54
55
56
57static void x25_disconnected(struct net_device *dev, int reason)
58{
59	x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
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 = X25_IFACE_DATA;
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 netdev_tx_t 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 X25_IFACE_DATA:	/* 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 NETDEV_TX_OK;
102
103	case X25_IFACE_CONNECT:
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				netdev_err(dev, "LAPB connect request failed, error code = %i\n",
110					   result);
111		}
112		break;
113
114	case X25_IFACE_DISCONNECT:
115		if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
116			if (result == LAPB_NOTCONNECTED)
117				/* Send disconnect confirm. msg to level 3 */
118				x25_disconnected(dev, 0);
119			else
120				netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
121					   result);
122		}
123		break;
124
125	default:		/* to be defined */
126		break;
127	}
128
129	dev_kfree_skb(skb);
130	return NETDEV_TX_OK;
131}
132
133
134
135static int x25_open(struct net_device *dev)
136{
137	int result;
138	static const struct lapb_register_struct cb = {
139		.connect_confirmation = x25_connected,
140		.connect_indication = x25_connected,
141		.disconnect_confirmation = x25_disconnected,
142		.disconnect_indication = x25_disconnected,
143		.data_indication = x25_data_indication,
144		.data_transmit = x25_data_transmit,
145	};
146
147	result = lapb_register(dev, &cb);
148	if (result != LAPB_OK)
149		return result;
150	return 0;
151}
152
153
154
155static void x25_close(struct net_device *dev)
156{
157	lapb_unregister(dev);
158}
159
160
161
162static int x25_rx(struct sk_buff *skb)
163{
164	struct net_device *dev = skb->dev;
165
166	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
167		dev->stats.rx_dropped++;
168		return NET_RX_DROP;
169	}
170
171	if (lapb_data_received(dev, skb) == LAPB_OK)
172		return NET_RX_SUCCESS;
173
174	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	.xmit		= x25_xmit,
186	.module		= THIS_MODULE,
187};
188
189
190static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
191{
192	hdlc_device *hdlc = dev_to_hdlc(dev);
193	int result;
194
195	switch (ifr->ifr_settings.type) {
196	case IF_GET_PROTO:
197		if (dev_to_hdlc(dev)->proto != &proto)
198			return -EINVAL;
199		ifr->ifr_settings.type = IF_PROTO_X25;
200		return 0; /* return protocol only, no settable parameters */
201
202	case IF_PROTO_X25:
203		if (!capable(CAP_NET_ADMIN))
204			return -EPERM;
205
206		if (dev->flags & IFF_UP)
207			return -EBUSY;
208
209		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
210		if (result)
211			return result;
212
213		if ((result = attach_hdlc_protocol(dev, &proto, 0)))
214			return result;
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