1/*
2 * Generic HDLC support routines for Linux
3 * Cisco HDLC support
4 *
5 * Copyright (C) 2000 - 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/module.h>
19#include <linux/pkt_sched.h>
20#include <linux/poll.h>
21#include <linux/rtnetlink.h>
22#include <linux/skbuff.h>
23
24#undef DEBUG_HARD_HEADER
25
26#define CISCO_MULTICAST		0x8F	/* Cisco multicast address */
27#define CISCO_UNICAST		0x0F	/* Cisco unicast address */
28#define CISCO_KEEPALIVE		0x8035	/* Cisco keepalive protocol */
29#define CISCO_SYS_INFO		0x2000	/* Cisco interface/system info */
30#define CISCO_ADDR_REQ		0	/* Cisco address request */
31#define CISCO_ADDR_REPLY	1	/* Cisco address reply */
32#define CISCO_KEEPALIVE_REQ	2	/* Cisco keepalive request */
33
34
35struct hdlc_header {
36	u8 address;
37	u8 control;
38	__be16 protocol;
39}__packed;
40
41
42struct cisco_packet {
43	__be32 type;		/* code */
44	__be32 par1;
45	__be32 par2;
46	__be16 rel;		/* reliability */
47	__be32 time;
48}__packed;
49#define	CISCO_PACKET_LEN	18
50#define	CISCO_BIG_PACKET_LEN	20
51
52
53struct cisco_state {
54	cisco_proto settings;
55
56	struct timer_list timer;
57	spinlock_t lock;
58	unsigned long last_poll;
59	int up;
60	u32 txseq; /* TX sequence number, 0 = none */
61	u32 rxseq; /* RX sequence number */
62};
63
64
65static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
66
67
68static inline struct cisco_state* state(hdlc_device *hdlc)
69{
70	return (struct cisco_state *)hdlc->state;
71}
72
73
74static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
75			     u16 type, const void *daddr, const void *saddr,
76			     unsigned int len)
77{
78	struct hdlc_header *data;
79#ifdef DEBUG_HARD_HEADER
80	printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name);
81#endif
82
83	skb_push(skb, sizeof(struct hdlc_header));
84	data = (struct hdlc_header*)skb->data;
85	if (type == CISCO_KEEPALIVE)
86		data->address = CISCO_MULTICAST;
87	else
88		data->address = CISCO_UNICAST;
89	data->control = 0;
90	data->protocol = htons(type);
91
92	return sizeof(struct hdlc_header);
93}
94
95
96
97static void cisco_keepalive_send(struct net_device *dev, u32 type,
98				 __be32 par1, __be32 par2)
99{
100	struct sk_buff *skb;
101	struct cisco_packet *data;
102
103	skb = dev_alloc_skb(sizeof(struct hdlc_header) +
104			    sizeof(struct cisco_packet));
105	if (!skb) {
106		netdev_warn(dev, "Memory squeeze on cisco_keepalive_send()\n");
107		return;
108	}
109	skb_reserve(skb, 4);
110	cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
111	data = (struct cisco_packet*)(skb->data + 4);
112
113	data->type = htonl(type);
114	data->par1 = par1;
115	data->par2 = par2;
116	data->rel = cpu_to_be16(0xFFFF);
117	/* we will need do_div here if 1000 % HZ != 0 */
118	data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
119
120	skb_put(skb, sizeof(struct cisco_packet));
121	skb->priority = TC_PRIO_CONTROL;
122	skb->dev = dev;
123	skb_reset_network_header(skb);
124
125	dev_queue_xmit(skb);
126}
127
128
129
130static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
131{
132	struct hdlc_header *data = (struct hdlc_header*)skb->data;
133
134	if (skb->len < sizeof(struct hdlc_header))
135		return cpu_to_be16(ETH_P_HDLC);
136
137	if (data->address != CISCO_MULTICAST &&
138	    data->address != CISCO_UNICAST)
139		return cpu_to_be16(ETH_P_HDLC);
140
141	switch (data->protocol) {
142	case cpu_to_be16(ETH_P_IP):
143	case cpu_to_be16(ETH_P_IPX):
144	case cpu_to_be16(ETH_P_IPV6):
145		skb_pull(skb, sizeof(struct hdlc_header));
146		return data->protocol;
147	default:
148		return cpu_to_be16(ETH_P_HDLC);
149	}
150}
151
152
153static int cisco_rx(struct sk_buff *skb)
154{
155	struct net_device *dev = skb->dev;
156	hdlc_device *hdlc = dev_to_hdlc(dev);
157	struct cisco_state *st = state(hdlc);
158	struct hdlc_header *data = (struct hdlc_header*)skb->data;
159	struct cisco_packet *cisco_data;
160	struct in_device *in_dev;
161	__be32 addr, mask;
162	u32 ack;
163
164	if (skb->len < sizeof(struct hdlc_header))
165		goto rx_error;
166
167	if (data->address != CISCO_MULTICAST &&
168	    data->address != CISCO_UNICAST)
169		goto rx_error;
170
171	switch (ntohs(data->protocol)) {
172	case CISCO_SYS_INFO:
173		/* Packet is not needed, drop it. */
174		dev_kfree_skb_any(skb);
175		return NET_RX_SUCCESS;
176
177	case CISCO_KEEPALIVE:
178		if ((skb->len != sizeof(struct hdlc_header) +
179		     CISCO_PACKET_LEN) &&
180		    (skb->len != sizeof(struct hdlc_header) +
181		     CISCO_BIG_PACKET_LEN)) {
182			netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n",
183				    skb->len);
184			goto rx_error;
185		}
186
187		cisco_data = (struct cisco_packet*)(skb->data + sizeof
188						    (struct hdlc_header));
189
190		switch (ntohl (cisco_data->type)) {
191		case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
192			rcu_read_lock();
193			in_dev = __in_dev_get_rcu(dev);
194			addr = 0;
195			mask = ~cpu_to_be32(0); /* is the mask correct? */
196
197			if (in_dev != NULL) {
198				struct in_ifaddr **ifap = &in_dev->ifa_list;
199
200				while (*ifap != NULL) {
201					if (strcmp(dev->name,
202						   (*ifap)->ifa_label) == 0) {
203						addr = (*ifap)->ifa_local;
204						mask = (*ifap)->ifa_mask;
205						break;
206					}
207					ifap = &(*ifap)->ifa_next;
208				}
209
210				cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
211						     addr, mask);
212			}
213			rcu_read_unlock();
214			dev_kfree_skb_any(skb);
215			return NET_RX_SUCCESS;
216
217		case CISCO_ADDR_REPLY:
218			netdev_info(dev, "Unexpected Cisco IP address reply\n");
219			goto rx_error;
220
221		case CISCO_KEEPALIVE_REQ:
222			spin_lock(&st->lock);
223			st->rxseq = ntohl(cisco_data->par1);
224			ack = ntohl(cisco_data->par2);
225			if (ack && (ack == st->txseq ||
226				    /* our current REQ may be in transit */
227				    ack == st->txseq - 1)) {
228				st->last_poll = jiffies;
229				if (!st->up) {
230					u32 sec, min, hrs, days;
231					sec = ntohl(cisco_data->time) / 1000;
232					min = sec / 60; sec -= min * 60;
233					hrs = min / 60; min -= hrs * 60;
234					days = hrs / 24; hrs -= days * 24;
235					netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n",
236						    days, hrs, min, sec);
237					netif_dormant_off(dev);
238					st->up = 1;
239				}
240			}
241			spin_unlock(&st->lock);
242
243			dev_kfree_skb_any(skb);
244			return NET_RX_SUCCESS;
245		} /* switch (keepalive type) */
246	} /* switch (protocol) */
247
248	netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol));
249	dev_kfree_skb_any(skb);
250	return NET_RX_DROP;
251
252rx_error:
253	dev->stats.rx_errors++; /* Mark error */
254	dev_kfree_skb_any(skb);
255	return NET_RX_DROP;
256}
257
258
259
260static void cisco_timer(unsigned long arg)
261{
262	struct net_device *dev = (struct net_device *)arg;
263	hdlc_device *hdlc = dev_to_hdlc(dev);
264	struct cisco_state *st = state(hdlc);
265
266	spin_lock(&st->lock);
267	if (st->up &&
268	    time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
269		st->up = 0;
270		netdev_info(dev, "Link down\n");
271		netif_dormant_on(dev);
272	}
273
274	cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
275			     htonl(st->rxseq));
276	spin_unlock(&st->lock);
277
278	st->timer.expires = jiffies + st->settings.interval * HZ;
279	st->timer.function = cisco_timer;
280	st->timer.data = arg;
281	add_timer(&st->timer);
282}
283
284
285
286static void cisco_start(struct net_device *dev)
287{
288	hdlc_device *hdlc = dev_to_hdlc(dev);
289	struct cisco_state *st = state(hdlc);
290	unsigned long flags;
291
292	spin_lock_irqsave(&st->lock, flags);
293	st->up = st->txseq = st->rxseq = 0;
294	spin_unlock_irqrestore(&st->lock, flags);
295
296	init_timer(&st->timer);
297	st->timer.expires = jiffies + HZ; /* First poll after 1 s */
298	st->timer.function = cisco_timer;
299	st->timer.data = (unsigned long)dev;
300	add_timer(&st->timer);
301}
302
303
304
305static void cisco_stop(struct net_device *dev)
306{
307	hdlc_device *hdlc = dev_to_hdlc(dev);
308	struct cisco_state *st = state(hdlc);
309	unsigned long flags;
310
311	del_timer_sync(&st->timer);
312
313	spin_lock_irqsave(&st->lock, flags);
314	netif_dormant_on(dev);
315	st->up = st->txseq = 0;
316	spin_unlock_irqrestore(&st->lock, flags);
317}
318
319
320static struct hdlc_proto proto = {
321	.start		= cisco_start,
322	.stop		= cisco_stop,
323	.type_trans	= cisco_type_trans,
324	.ioctl		= cisco_ioctl,
325	.netif_rx	= cisco_rx,
326	.module		= THIS_MODULE,
327};
328
329static const struct header_ops cisco_header_ops = {
330	.create = cisco_hard_header,
331};
332
333static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
334{
335	cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
336	const size_t size = sizeof(cisco_proto);
337	cisco_proto new_settings;
338	hdlc_device *hdlc = dev_to_hdlc(dev);
339	int result;
340
341	switch (ifr->ifr_settings.type) {
342	case IF_GET_PROTO:
343		if (dev_to_hdlc(dev)->proto != &proto)
344			return -EINVAL;
345		ifr->ifr_settings.type = IF_PROTO_CISCO;
346		if (ifr->ifr_settings.size < size) {
347			ifr->ifr_settings.size = size; /* data size wanted */
348			return -ENOBUFS;
349		}
350		if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
351			return -EFAULT;
352		return 0;
353
354	case IF_PROTO_CISCO:
355		if (!capable(CAP_NET_ADMIN))
356			return -EPERM;
357
358		if (dev->flags & IFF_UP)
359			return -EBUSY;
360
361		if (copy_from_user(&new_settings, cisco_s, size))
362			return -EFAULT;
363
364		if (new_settings.interval < 1 ||
365		    new_settings.timeout < 2)
366			return -EINVAL;
367
368		result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
369		if (result)
370			return result;
371
372		result = attach_hdlc_protocol(dev, &proto,
373					      sizeof(struct cisco_state));
374		if (result)
375			return result;
376
377		memcpy(&state(hdlc)->settings, &new_settings, size);
378		spin_lock_init(&state(hdlc)->lock);
379		dev->header_ops = &cisco_header_ops;
380		dev->type = ARPHRD_CISCO;
381		netif_dormant_on(dev);
382		return 0;
383	}
384
385	return -EINVAL;
386}
387
388
389static int __init mod_init(void)
390{
391	register_hdlc_protocol(&proto);
392	return 0;
393}
394
395
396
397static void __exit mod_exit(void)
398{
399	unregister_hdlc_protocol(&proto);
400}
401
402
403module_init(mod_init);
404module_exit(mod_exit);
405
406MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
407MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
408MODULE_LICENSE("GPL v2");
409