Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / drivers / net / wan / hdlc_cisco.c
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                 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
130 static __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
153 static 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
252 rx_error:
253         dev->stats.rx_errors++; /* Mark error */
254         dev_kfree_skb_any(skb);
255         return NET_RX_DROP;
256 }
257
258
259
260 static 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
286 static 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
305 static 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
320 static 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
329 static const struct header_ops cisco_header_ops = {
330         .create = cisco_hard_header,
331 };
332
333 static 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
389 static int __init mod_init(void)
390 {
391         register_hdlc_protocol(&proto);
392         return 0;
393 }
394
395
396
397 static void __exit mod_exit(void)
398 {
399         unregister_hdlc_protocol(&proto);
400 }
401
402
403 module_init(mod_init);
404 module_exit(mod_exit);
405
406 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
407 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
408 MODULE_LICENSE("GPL v2");