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
state(hdlc_device * hdlc)68 static inline struct cisco_state* state(hdlc_device *hdlc)
69 {
70 return (struct cisco_state *)hdlc->state;
71 }
72
73
cisco_hard_header(struct sk_buff * skb,struct net_device * dev,u16 type,const void * daddr,const void * saddr,unsigned int len)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
cisco_keepalive_send(struct net_device * dev,u32 type,__be32 par1,__be32 par2)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 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->protocol = htons(ETH_P_HDLC);
124 skb_reset_network_header(skb);
125
126 dev_queue_xmit(skb);
127 }
128
129
130
cisco_type_trans(struct sk_buff * skb,struct net_device * dev)131 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
132 {
133 struct hdlc_header *data = (struct hdlc_header*)skb->data;
134
135 if (skb->len < sizeof(struct hdlc_header))
136 return cpu_to_be16(ETH_P_HDLC);
137
138 if (data->address != CISCO_MULTICAST &&
139 data->address != CISCO_UNICAST)
140 return cpu_to_be16(ETH_P_HDLC);
141
142 switch (data->protocol) {
143 case cpu_to_be16(ETH_P_IP):
144 case cpu_to_be16(ETH_P_IPX):
145 case cpu_to_be16(ETH_P_IPV6):
146 skb_pull(skb, sizeof(struct hdlc_header));
147 return data->protocol;
148 default:
149 return cpu_to_be16(ETH_P_HDLC);
150 }
151 }
152
153
cisco_rx(struct sk_buff * skb)154 static int cisco_rx(struct sk_buff *skb)
155 {
156 struct net_device *dev = skb->dev;
157 hdlc_device *hdlc = dev_to_hdlc(dev);
158 struct cisco_state *st = state(hdlc);
159 struct hdlc_header *data = (struct hdlc_header*)skb->data;
160 struct cisco_packet *cisco_data;
161 struct in_device *in_dev;
162 __be32 addr, mask;
163 u32 ack;
164
165 if (skb->len < sizeof(struct hdlc_header))
166 goto rx_error;
167
168 if (data->address != CISCO_MULTICAST &&
169 data->address != CISCO_UNICAST)
170 goto rx_error;
171
172 switch (ntohs(data->protocol)) {
173 case CISCO_SYS_INFO:
174 /* Packet is not needed, drop it. */
175 dev_kfree_skb_any(skb);
176 return NET_RX_SUCCESS;
177
178 case CISCO_KEEPALIVE:
179 if ((skb->len != sizeof(struct hdlc_header) +
180 CISCO_PACKET_LEN) &&
181 (skb->len != sizeof(struct hdlc_header) +
182 CISCO_BIG_PACKET_LEN)) {
183 netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n",
184 skb->len);
185 goto rx_error;
186 }
187
188 cisco_data = (struct cisco_packet*)(skb->data + sizeof
189 (struct hdlc_header));
190
191 switch (ntohl (cisco_data->type)) {
192 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
193 rcu_read_lock();
194 in_dev = __in_dev_get_rcu(dev);
195 addr = 0;
196 mask = ~cpu_to_be32(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 rcu_read_unlock();
215 dev_kfree_skb_any(skb);
216 return NET_RX_SUCCESS;
217
218 case CISCO_ADDR_REPLY:
219 netdev_info(dev, "Unexpected Cisco IP address reply\n");
220 goto rx_error;
221
222 case CISCO_KEEPALIVE_REQ:
223 spin_lock(&st->lock);
224 st->rxseq = ntohl(cisco_data->par1);
225 ack = ntohl(cisco_data->par2);
226 if (ack && (ack == st->txseq ||
227 /* our current REQ may be in transit */
228 ack == st->txseq - 1)) {
229 st->last_poll = jiffies;
230 if (!st->up) {
231 u32 sec, min, hrs, days;
232 sec = ntohl(cisco_data->time) / 1000;
233 min = sec / 60; sec -= min * 60;
234 hrs = min / 60; min -= hrs * 60;
235 days = hrs / 24; hrs -= days * 24;
236 netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n",
237 days, hrs, min, sec);
238 netif_dormant_off(dev);
239 st->up = 1;
240 }
241 }
242 spin_unlock(&st->lock);
243
244 dev_kfree_skb_any(skb);
245 return NET_RX_SUCCESS;
246 } /* switch (keepalive type) */
247 } /* switch (protocol) */
248
249 netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol));
250 dev_kfree_skb_any(skb);
251 return NET_RX_DROP;
252
253 rx_error:
254 dev->stats.rx_errors++; /* Mark error */
255 dev_kfree_skb_any(skb);
256 return NET_RX_DROP;
257 }
258
259
260
cisco_timer(unsigned long arg)261 static void cisco_timer(unsigned long arg)
262 {
263 struct net_device *dev = (struct net_device *)arg;
264 hdlc_device *hdlc = dev_to_hdlc(dev);
265 struct cisco_state *st = state(hdlc);
266
267 spin_lock(&st->lock);
268 if (st->up &&
269 time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
270 st->up = 0;
271 netdev_info(dev, "Link down\n");
272 netif_dormant_on(dev);
273 }
274
275 cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
276 htonl(st->rxseq));
277 spin_unlock(&st->lock);
278
279 st->timer.expires = jiffies + st->settings.interval * HZ;
280 st->timer.function = cisco_timer;
281 st->timer.data = arg;
282 add_timer(&st->timer);
283 }
284
285
286
cisco_start(struct net_device * dev)287 static void cisco_start(struct net_device *dev)
288 {
289 hdlc_device *hdlc = dev_to_hdlc(dev);
290 struct cisco_state *st = state(hdlc);
291 unsigned long flags;
292
293 spin_lock_irqsave(&st->lock, flags);
294 st->up = st->txseq = st->rxseq = 0;
295 spin_unlock_irqrestore(&st->lock, flags);
296
297 init_timer(&st->timer);
298 st->timer.expires = jiffies + HZ; /* First poll after 1 s */
299 st->timer.function = cisco_timer;
300 st->timer.data = (unsigned long)dev;
301 add_timer(&st->timer);
302 }
303
304
305
cisco_stop(struct net_device * dev)306 static void cisco_stop(struct net_device *dev)
307 {
308 hdlc_device *hdlc = dev_to_hdlc(dev);
309 struct cisco_state *st = state(hdlc);
310 unsigned long flags;
311
312 del_timer_sync(&st->timer);
313
314 spin_lock_irqsave(&st->lock, flags);
315 netif_dormant_on(dev);
316 st->up = st->txseq = 0;
317 spin_unlock_irqrestore(&st->lock, flags);
318 }
319
320
321 static struct hdlc_proto proto = {
322 .start = cisco_start,
323 .stop = cisco_stop,
324 .type_trans = cisco_type_trans,
325 .ioctl = cisco_ioctl,
326 .netif_rx = cisco_rx,
327 .module = THIS_MODULE,
328 };
329
330 static const struct header_ops cisco_header_ops = {
331 .create = cisco_hard_header,
332 };
333
cisco_ioctl(struct net_device * dev,struct ifreq * ifr)334 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
335 {
336 cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
337 const size_t size = sizeof(cisco_proto);
338 cisco_proto new_settings;
339 hdlc_device *hdlc = dev_to_hdlc(dev);
340 int result;
341
342 switch (ifr->ifr_settings.type) {
343 case IF_GET_PROTO:
344 if (dev_to_hdlc(dev)->proto != &proto)
345 return -EINVAL;
346 ifr->ifr_settings.type = IF_PROTO_CISCO;
347 if (ifr->ifr_settings.size < size) {
348 ifr->ifr_settings.size = size; /* data size wanted */
349 return -ENOBUFS;
350 }
351 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
352 return -EFAULT;
353 return 0;
354
355 case IF_PROTO_CISCO:
356 if (!capable(CAP_NET_ADMIN))
357 return -EPERM;
358
359 if (dev->flags & IFF_UP)
360 return -EBUSY;
361
362 if (copy_from_user(&new_settings, cisco_s, size))
363 return -EFAULT;
364
365 if (new_settings.interval < 1 ||
366 new_settings.timeout < 2)
367 return -EINVAL;
368
369 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
370 if (result)
371 return result;
372
373 result = attach_hdlc_protocol(dev, &proto,
374 sizeof(struct cisco_state));
375 if (result)
376 return result;
377
378 memcpy(&state(hdlc)->settings, &new_settings, size);
379 spin_lock_init(&state(hdlc)->lock);
380 dev->header_ops = &cisco_header_ops;
381 dev->hard_header_len = sizeof(struct hdlc_header);
382 dev->type = ARPHRD_CISCO;
383 netif_dormant_on(dev);
384 return 0;
385 }
386
387 return -EINVAL;
388 }
389
390
mod_init(void)391 static int __init mod_init(void)
392 {
393 register_hdlc_protocol(&proto);
394 return 0;
395 }
396
397
398
mod_exit(void)399 static void __exit mod_exit(void)
400 {
401 unregister_hdlc_protocol(&proto);
402 }
403
404
405 module_init(mod_init);
406 module_exit(mod_exit);
407
408 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
409 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
410 MODULE_LICENSE("GPL v2");
411