xref: /openbmc/linux/drivers/net/wan/hdlc_cisco.c (revision 4800cd83)
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 
35 struct hdlc_header {
36 	u8 address;
37 	u8 control;
38 	__be16 protocol;
39 }__packed;
40 
41 
42 struct 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 
53 struct 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 
65 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
66 
67 
68 static inline struct cisco_state* state(hdlc_device *hdlc)
69 {
70 	return (struct cisco_state *)hdlc->state;
71 }
72 
73 
74 static 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 
97 static 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 		printk(KERN_WARNING
107 		       "%s: Memory squeeze on cisco_keepalive_send()\n",
108 		       dev->name);
109 		return;
110 	}
111 	skb_reserve(skb, 4);
112 	cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
113 	data = (struct cisco_packet*)(skb->data + 4);
114 
115 	data->type = htonl(type);
116 	data->par1 = par1;
117 	data->par2 = par2;
118 	data->rel = cpu_to_be16(0xFFFF);
119 	/* we will need do_div here if 1000 % HZ != 0 */
120 	data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
121 
122 	skb_put(skb, sizeof(struct cisco_packet));
123 	skb->priority = TC_PRIO_CONTROL;
124 	skb->dev = dev;
125 	skb_reset_network_header(skb);
126 
127 	dev_queue_xmit(skb);
128 }
129 
130 
131 
132 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
133 {
134 	struct hdlc_header *data = (struct hdlc_header*)skb->data;
135 
136 	if (skb->len < sizeof(struct hdlc_header))
137 		return cpu_to_be16(ETH_P_HDLC);
138 
139 	if (data->address != CISCO_MULTICAST &&
140 	    data->address != CISCO_UNICAST)
141 		return cpu_to_be16(ETH_P_HDLC);
142 
143 	switch (data->protocol) {
144 	case cpu_to_be16(ETH_P_IP):
145 	case cpu_to_be16(ETH_P_IPX):
146 	case cpu_to_be16(ETH_P_IPV6):
147 		skb_pull(skb, sizeof(struct hdlc_header));
148 		return data->protocol;
149 	default:
150 		return cpu_to_be16(ETH_P_HDLC);
151 	}
152 }
153 
154 
155 static int cisco_rx(struct sk_buff *skb)
156 {
157 	struct net_device *dev = skb->dev;
158 	hdlc_device *hdlc = dev_to_hdlc(dev);
159 	struct cisco_state *st = state(hdlc);
160 	struct hdlc_header *data = (struct hdlc_header*)skb->data;
161 	struct cisco_packet *cisco_data;
162 	struct in_device *in_dev;
163 	__be32 addr, mask;
164 	u32 ack;
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 			rcu_read_lock();
195 			in_dev = __in_dev_get_rcu(dev);
196 			addr = 0;
197 			mask = ~cpu_to_be32(0); /* is the mask correct? */
198 
199 			if (in_dev != NULL) {
200 				struct in_ifaddr **ifap = &in_dev->ifa_list;
201 
202 				while (*ifap != NULL) {
203 					if (strcmp(dev->name,
204 						   (*ifap)->ifa_label) == 0) {
205 						addr = (*ifap)->ifa_local;
206 						mask = (*ifap)->ifa_mask;
207 						break;
208 					}
209 					ifap = &(*ifap)->ifa_next;
210 				}
211 
212 				cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
213 						     addr, mask);
214 			}
215 			rcu_read_unlock();
216 			dev_kfree_skb_any(skb);
217 			return NET_RX_SUCCESS;
218 
219 		case CISCO_ADDR_REPLY:
220 			printk(KERN_INFO "%s: Unexpected Cisco IP address "
221 			       "reply\n", dev->name);
222 			goto rx_error;
223 
224 		case CISCO_KEEPALIVE_REQ:
225 			spin_lock(&st->lock);
226 			st->rxseq = ntohl(cisco_data->par1);
227 			ack = ntohl(cisco_data->par2);
228 			if (ack && (ack == st->txseq ||
229 				    /* our current REQ may be in transit */
230 				    ack == st->txseq - 1)) {
231 				st->last_poll = jiffies;
232 				if (!st->up) {
233 					u32 sec, min, hrs, days;
234 					sec = ntohl(cisco_data->time) / 1000;
235 					min = sec / 60; sec -= min * 60;
236 					hrs = min / 60; min -= hrs * 60;
237 					days = hrs / 24; hrs -= days * 24;
238 					printk(KERN_INFO "%s: Link up (peer "
239 					       "uptime %ud%uh%um%us)\n",
240 					       dev->name, days, hrs, min, sec);
241 					netif_dormant_off(dev);
242 					st->up = 1;
243 				}
244 			}
245 			spin_unlock(&st->lock);
246 
247 			dev_kfree_skb_any(skb);
248 			return NET_RX_SUCCESS;
249 		} /* switch (keepalive type) */
250 	} /* switch (protocol) */
251 
252 	printk(KERN_INFO "%s: Unsupported protocol %x\n", dev->name,
253 	       ntohs(data->protocol));
254 	dev_kfree_skb_any(skb);
255 	return NET_RX_DROP;
256 
257 rx_error:
258 	dev->stats.rx_errors++; /* Mark error */
259 	dev_kfree_skb_any(skb);
260 	return NET_RX_DROP;
261 }
262 
263 
264 
265 static void cisco_timer(unsigned long arg)
266 {
267 	struct net_device *dev = (struct net_device *)arg;
268 	hdlc_device *hdlc = dev_to_hdlc(dev);
269 	struct cisco_state *st = state(hdlc);
270 
271 	spin_lock(&st->lock);
272 	if (st->up &&
273 	    time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
274 		st->up = 0;
275 		printk(KERN_INFO "%s: Link down\n", dev->name);
276 		netif_dormant_on(dev);
277 	}
278 
279 	cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
280 			     htonl(st->rxseq));
281 	spin_unlock(&st->lock);
282 
283 	st->timer.expires = jiffies + st->settings.interval * HZ;
284 	st->timer.function = cisco_timer;
285 	st->timer.data = arg;
286 	add_timer(&st->timer);
287 }
288 
289 
290 
291 static void cisco_start(struct net_device *dev)
292 {
293 	hdlc_device *hdlc = dev_to_hdlc(dev);
294 	struct cisco_state *st = state(hdlc);
295 	unsigned long flags;
296 
297 	spin_lock_irqsave(&st->lock, flags);
298 	st->up = st->txseq = st->rxseq = 0;
299 	spin_unlock_irqrestore(&st->lock, flags);
300 
301 	init_timer(&st->timer);
302 	st->timer.expires = jiffies + HZ; /* First poll after 1 s */
303 	st->timer.function = cisco_timer;
304 	st->timer.data = (unsigned long)dev;
305 	add_timer(&st->timer);
306 }
307 
308 
309 
310 static void cisco_stop(struct net_device *dev)
311 {
312 	hdlc_device *hdlc = dev_to_hdlc(dev);
313 	struct cisco_state *st = state(hdlc);
314 	unsigned long flags;
315 
316 	del_timer_sync(&st->timer);
317 
318 	spin_lock_irqsave(&st->lock, flags);
319 	netif_dormant_on(dev);
320 	st->up = st->txseq = 0;
321 	spin_unlock_irqrestore(&st->lock, flags);
322 }
323 
324 
325 static struct hdlc_proto proto = {
326 	.start		= cisco_start,
327 	.stop		= cisco_stop,
328 	.type_trans	= cisco_type_trans,
329 	.ioctl		= cisco_ioctl,
330 	.netif_rx	= cisco_rx,
331 	.module		= THIS_MODULE,
332 };
333 
334 static const struct header_ops cisco_header_ops = {
335 	.create = cisco_hard_header,
336 };
337 
338 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
339 {
340 	cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
341 	const size_t size = sizeof(cisco_proto);
342 	cisco_proto new_settings;
343 	hdlc_device *hdlc = dev_to_hdlc(dev);
344 	int result;
345 
346 	switch (ifr->ifr_settings.type) {
347 	case IF_GET_PROTO:
348 		if (dev_to_hdlc(dev)->proto != &proto)
349 			return -EINVAL;
350 		ifr->ifr_settings.type = IF_PROTO_CISCO;
351 		if (ifr->ifr_settings.size < size) {
352 			ifr->ifr_settings.size = size; /* data size wanted */
353 			return -ENOBUFS;
354 		}
355 		if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
356 			return -EFAULT;
357 		return 0;
358 
359 	case IF_PROTO_CISCO:
360 		if (!capable(CAP_NET_ADMIN))
361 			return -EPERM;
362 
363 		if (dev->flags & IFF_UP)
364 			return -EBUSY;
365 
366 		if (copy_from_user(&new_settings, cisco_s, size))
367 			return -EFAULT;
368 
369 		if (new_settings.interval < 1 ||
370 		    new_settings.timeout < 2)
371 			return -EINVAL;
372 
373 		result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
374 		if (result)
375 			return result;
376 
377 		result = attach_hdlc_protocol(dev, &proto,
378 					      sizeof(struct cisco_state));
379 		if (result)
380 			return result;
381 
382 		memcpy(&state(hdlc)->settings, &new_settings, size);
383 		spin_lock_init(&state(hdlc)->lock);
384 		dev->header_ops = &cisco_header_ops;
385 		dev->type = ARPHRD_CISCO;
386 		netif_dormant_on(dev);
387 		return 0;
388 	}
389 
390 	return -EINVAL;
391 }
392 
393 
394 static int __init mod_init(void)
395 {
396 	register_hdlc_protocol(&proto);
397 	return 0;
398 }
399 
400 
401 
402 static void __exit mod_exit(void)
403 {
404 	unregister_hdlc_protocol(&proto);
405 }
406 
407 
408 module_init(mod_init);
409 module_exit(mod_exit);
410 
411 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
412 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
413 MODULE_LICENSE("GPL v2");
414