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