xref: /openbmc/linux/drivers/net/wan/hdlc_fr.c (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44)
1 /*
2  * Generic HDLC support routines for Linux
3  * Frame Relay support
4  *
5  * Copyright (C) 1999 - 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             Theory of PVC state
13 
14  DCE mode:
15 
16  (exist,new) -> 0,0 when "PVC create" or if "link unreliable"
17          0,x -> 1,1 if "link reliable" when sending FULL STATUS
18          1,1 -> 1,0 if received FULL STATUS ACK
19 
20  (active)    -> 0 when "ifconfig PVC down" or "link unreliable" or "PVC create"
21              -> 1 when "PVC up" and (exist,new) = 1,0
22 
23  DTE mode:
24  (exist,new,active) = FULL STATUS if "link reliable"
25 		    = 0, 0, 0 if "link unreliable"
26  No LMI:
27  active = open and "link reliable"
28  exist = new = not used
29 
30  CCITT LMI: ITU-T Q.933 Annex A
31  ANSI LMI: ANSI T1.617 Annex D
32  CISCO LMI: the original, aka "Gang of Four" LMI
33 
34 */
35 
36 #include <linux/module.h>
37 #include <linux/kernel.h>
38 #include <linux/slab.h>
39 #include <linux/poll.h>
40 #include <linux/errno.h>
41 #include <linux/if_arp.h>
42 #include <linux/init.h>
43 #include <linux/skbuff.h>
44 #include <linux/pkt_sched.h>
45 #include <linux/inetdevice.h>
46 #include <linux/lapb.h>
47 #include <linux/rtnetlink.h>
48 #include <linux/etherdevice.h>
49 #include <linux/hdlc.h>
50 
51 #undef DEBUG_PKT
52 #undef DEBUG_ECN
53 #undef DEBUG_LINK
54 #undef DEBUG_PROTO
55 #undef DEBUG_PVC
56 
57 #define FR_UI			0x03
58 #define FR_PAD			0x00
59 
60 #define NLPID_IP		0xCC
61 #define NLPID_IPV6		0x8E
62 #define NLPID_SNAP		0x80
63 #define NLPID_PAD		0x00
64 #define NLPID_CCITT_ANSI_LMI	0x08
65 #define NLPID_CISCO_LMI		0x09
66 
67 
68 #define LMI_CCITT_ANSI_DLCI	   0 /* LMI DLCI */
69 #define LMI_CISCO_DLCI		1023
70 
71 #define LMI_CALLREF		0x00 /* Call Reference */
72 #define LMI_ANSI_LOCKSHIFT	0x95 /* ANSI locking shift */
73 #define LMI_ANSI_CISCO_REPTYPE	0x01 /* report type */
74 #define LMI_CCITT_REPTYPE	0x51
75 #define LMI_ANSI_CISCO_ALIVE	0x03 /* keep alive */
76 #define LMI_CCITT_ALIVE		0x53
77 #define LMI_ANSI_CISCO_PVCSTAT	0x07 /* PVC status */
78 #define LMI_CCITT_PVCSTAT	0x57
79 
80 #define LMI_FULLREP		0x00 /* full report  */
81 #define LMI_INTEGRITY		0x01 /* link integrity report */
82 #define LMI_SINGLE		0x02 /* single PVC report */
83 
84 #define LMI_STATUS_ENQUIRY      0x75
85 #define LMI_STATUS              0x7D /* reply */
86 
87 #define LMI_REPT_LEN               1 /* report type element length */
88 #define LMI_INTEG_LEN              2 /* link integrity element length */
89 
90 #define LMI_CCITT_CISCO_LENGTH	  13 /* LMI frame lengths */
91 #define LMI_ANSI_LENGTH		  14
92 
93 
94 typedef struct {
95 #if defined(__LITTLE_ENDIAN_BITFIELD)
96 	unsigned ea1:	1;
97 	unsigned cr:	1;
98 	unsigned dlcih:	6;
99 
100 	unsigned ea2:	1;
101 	unsigned de:	1;
102 	unsigned becn:	1;
103 	unsigned fecn:	1;
104 	unsigned dlcil:	4;
105 #else
106 	unsigned dlcih:	6;
107 	unsigned cr:	1;
108 	unsigned ea1:	1;
109 
110 	unsigned dlcil:	4;
111 	unsigned fecn:	1;
112 	unsigned becn:	1;
113 	unsigned de:	1;
114 	unsigned ea2:	1;
115 #endif
116 }__attribute__ ((packed)) fr_hdr;
117 
118 
119 typedef struct pvc_device_struct {
120 	struct net_device *frad;
121 	struct net_device *main;
122 	struct net_device *ether;	/* bridged Ethernet interface	*/
123 	struct pvc_device_struct *next;	/* Sorted in ascending DLCI order */
124 	int dlci;
125 	int open_count;
126 
127 	struct {
128 		unsigned int new: 1;
129 		unsigned int active: 1;
130 		unsigned int exist: 1;
131 		unsigned int deleted: 1;
132 		unsigned int fecn: 1;
133 		unsigned int becn: 1;
134 		unsigned int bandwidth;	/* Cisco LMI reporting only */
135 	}state;
136 }pvc_device;
137 
138 struct frad_state {
139 	fr_proto settings;
140 	pvc_device *first_pvc;
141 	int dce_pvc_count;
142 
143 	struct timer_list timer;
144 	unsigned long last_poll;
145 	int reliable;
146 	int dce_changed;
147 	int request;
148 	int fullrep_sent;
149 	u32 last_errors; /* last errors bit list */
150 	u8 n391cnt;
151 	u8 txseq; /* TX sequence number */
152 	u8 rxseq; /* RX sequence number */
153 };
154 
155 
156 static int fr_ioctl(struct net_device *dev, struct ifreq *ifr);
157 
158 
159 static inline u16 q922_to_dlci(u8 *hdr)
160 {
161 	return ((hdr[0] & 0xFC) << 2) | ((hdr[1] & 0xF0) >> 4);
162 }
163 
164 
165 static inline void dlci_to_q922(u8 *hdr, u16 dlci)
166 {
167 	hdr[0] = (dlci >> 2) & 0xFC;
168 	hdr[1] = ((dlci << 4) & 0xF0) | 0x01;
169 }
170 
171 
172 static inline struct frad_state* state(hdlc_device *hdlc)
173 {
174 	return(struct frad_state *)(hdlc->state);
175 }
176 
177 
178 static inline pvc_device* find_pvc(hdlc_device *hdlc, u16 dlci)
179 {
180 	pvc_device *pvc = state(hdlc)->first_pvc;
181 
182 	while (pvc) {
183 		if (pvc->dlci == dlci)
184 			return pvc;
185 		if (pvc->dlci > dlci)
186 			return NULL; /* the listed is sorted */
187 		pvc = pvc->next;
188 	}
189 
190 	return NULL;
191 }
192 
193 
194 static pvc_device* add_pvc(struct net_device *dev, u16 dlci)
195 {
196 	hdlc_device *hdlc = dev_to_hdlc(dev);
197 	pvc_device *pvc, **pvc_p = &state(hdlc)->first_pvc;
198 
199 	while (*pvc_p) {
200 		if ((*pvc_p)->dlci == dlci)
201 			return *pvc_p;
202 		if ((*pvc_p)->dlci > dlci)
203 			break;	/* the list is sorted */
204 		pvc_p = &(*pvc_p)->next;
205 	}
206 
207 	pvc = kzalloc(sizeof(pvc_device), GFP_ATOMIC);
208 #ifdef DEBUG_PVC
209 	printk(KERN_DEBUG "add_pvc: allocated pvc %p, frad %p\n", pvc, dev);
210 #endif
211 	if (!pvc)
212 		return NULL;
213 
214 	pvc->dlci = dlci;
215 	pvc->frad = dev;
216 	pvc->next = *pvc_p;	/* Put it in the chain */
217 	*pvc_p = pvc;
218 	return pvc;
219 }
220 
221 
222 static inline int pvc_is_used(pvc_device *pvc)
223 {
224 	return pvc->main || pvc->ether;
225 }
226 
227 
228 static inline void pvc_carrier(int on, pvc_device *pvc)
229 {
230 	if (on) {
231 		if (pvc->main)
232 			if (!netif_carrier_ok(pvc->main))
233 				netif_carrier_on(pvc->main);
234 		if (pvc->ether)
235 			if (!netif_carrier_ok(pvc->ether))
236 				netif_carrier_on(pvc->ether);
237 	} else {
238 		if (pvc->main)
239 			if (netif_carrier_ok(pvc->main))
240 				netif_carrier_off(pvc->main);
241 		if (pvc->ether)
242 			if (netif_carrier_ok(pvc->ether))
243 				netif_carrier_off(pvc->ether);
244 	}
245 }
246 
247 
248 static inline void delete_unused_pvcs(hdlc_device *hdlc)
249 {
250 	pvc_device **pvc_p = &state(hdlc)->first_pvc;
251 
252 	while (*pvc_p) {
253 		if (!pvc_is_used(*pvc_p)) {
254 			pvc_device *pvc = *pvc_p;
255 #ifdef DEBUG_PVC
256 			printk(KERN_DEBUG "freeing unused pvc: %p\n", pvc);
257 #endif
258 			*pvc_p = pvc->next;
259 			kfree(pvc);
260 			continue;
261 		}
262 		pvc_p = &(*pvc_p)->next;
263 	}
264 }
265 
266 
267 static inline struct net_device** get_dev_p(pvc_device *pvc, int type)
268 {
269 	if (type == ARPHRD_ETHER)
270 		return &pvc->ether;
271 	else
272 		return &pvc->main;
273 }
274 
275 
276 static int fr_hard_header(struct sk_buff **skb_p, u16 dlci)
277 {
278 	u16 head_len;
279 	struct sk_buff *skb = *skb_p;
280 
281 	switch (skb->protocol) {
282 	case __constant_htons(NLPID_CCITT_ANSI_LMI):
283 		head_len = 4;
284 		skb_push(skb, head_len);
285 		skb->data[3] = NLPID_CCITT_ANSI_LMI;
286 		break;
287 
288 	case __constant_htons(NLPID_CISCO_LMI):
289 		head_len = 4;
290 		skb_push(skb, head_len);
291 		skb->data[3] = NLPID_CISCO_LMI;
292 		break;
293 
294 	case __constant_htons(ETH_P_IP):
295 		head_len = 4;
296 		skb_push(skb, head_len);
297 		skb->data[3] = NLPID_IP;
298 		break;
299 
300 	case __constant_htons(ETH_P_IPV6):
301 		head_len = 4;
302 		skb_push(skb, head_len);
303 		skb->data[3] = NLPID_IPV6;
304 		break;
305 
306 	case __constant_htons(ETH_P_802_3):
307 		head_len = 10;
308 		if (skb_headroom(skb) < head_len) {
309 			struct sk_buff *skb2 = skb_realloc_headroom(skb,
310 								    head_len);
311 			if (!skb2)
312 				return -ENOBUFS;
313 			dev_kfree_skb(skb);
314 			skb = *skb_p = skb2;
315 		}
316 		skb_push(skb, head_len);
317 		skb->data[3] = FR_PAD;
318 		skb->data[4] = NLPID_SNAP;
319 		skb->data[5] = FR_PAD;
320 		skb->data[6] = 0x80;
321 		skb->data[7] = 0xC2;
322 		skb->data[8] = 0x00;
323 		skb->data[9] = 0x07; /* bridged Ethernet frame w/out FCS */
324 		break;
325 
326 	default:
327 		head_len = 10;
328 		skb_push(skb, head_len);
329 		skb->data[3] = FR_PAD;
330 		skb->data[4] = NLPID_SNAP;
331 		skb->data[5] = FR_PAD;
332 		skb->data[6] = FR_PAD;
333 		skb->data[7] = FR_PAD;
334 		*(__be16*)(skb->data + 8) = skb->protocol;
335 	}
336 
337 	dlci_to_q922(skb->data, dlci);
338 	skb->data[2] = FR_UI;
339 	return 0;
340 }
341 
342 
343 
344 static int pvc_open(struct net_device *dev)
345 {
346 	pvc_device *pvc = dev->priv;
347 
348 	if ((pvc->frad->flags & IFF_UP) == 0)
349 		return -EIO;  /* Frad must be UP in order to activate PVC */
350 
351 	if (pvc->open_count++ == 0) {
352 		hdlc_device *hdlc = dev_to_hdlc(pvc->frad);
353 		if (state(hdlc)->settings.lmi == LMI_NONE)
354 			pvc->state.active = netif_carrier_ok(pvc->frad);
355 
356 		pvc_carrier(pvc->state.active, pvc);
357 		state(hdlc)->dce_changed = 1;
358 	}
359 	return 0;
360 }
361 
362 
363 
364 static int pvc_close(struct net_device *dev)
365 {
366 	pvc_device *pvc = dev->priv;
367 
368 	if (--pvc->open_count == 0) {
369 		hdlc_device *hdlc = dev_to_hdlc(pvc->frad);
370 		if (state(hdlc)->settings.lmi == LMI_NONE)
371 			pvc->state.active = 0;
372 
373 		if (state(hdlc)->settings.dce) {
374 			state(hdlc)->dce_changed = 1;
375 			pvc->state.active = 0;
376 		}
377 	}
378 	return 0;
379 }
380 
381 
382 
383 static int pvc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
384 {
385 	pvc_device *pvc = dev->priv;
386 	fr_proto_pvc_info info;
387 
388 	if (ifr->ifr_settings.type == IF_GET_PROTO) {
389 		if (dev->type == ARPHRD_ETHER)
390 			ifr->ifr_settings.type = IF_PROTO_FR_ETH_PVC;
391 		else
392 			ifr->ifr_settings.type = IF_PROTO_FR_PVC;
393 
394 		if (ifr->ifr_settings.size < sizeof(info)) {
395 			/* data size wanted */
396 			ifr->ifr_settings.size = sizeof(info);
397 			return -ENOBUFS;
398 		}
399 
400 		info.dlci = pvc->dlci;
401 		memcpy(info.master, pvc->frad->name, IFNAMSIZ);
402 		if (copy_to_user(ifr->ifr_settings.ifs_ifsu.fr_pvc_info,
403 				 &info, sizeof(info)))
404 			return -EFAULT;
405 		return 0;
406 	}
407 
408 	return -EINVAL;
409 }
410 
411 static int pvc_xmit(struct sk_buff *skb, struct net_device *dev)
412 {
413 	pvc_device *pvc = dev->priv;
414 
415 	if (pvc->state.active) {
416 		if (dev->type == ARPHRD_ETHER) {
417 			int pad = ETH_ZLEN - skb->len;
418 			if (pad > 0) { /* Pad the frame with zeros */
419 				int len = skb->len;
420 				if (skb_tailroom(skb) < pad)
421 					if (pskb_expand_head(skb, 0, pad,
422 							     GFP_ATOMIC)) {
423 						dev->stats.tx_dropped++;
424 						dev_kfree_skb(skb);
425 						return 0;
426 					}
427 				skb_put(skb, pad);
428 				memset(skb->data + len, 0, pad);
429 			}
430 			skb->protocol = __constant_htons(ETH_P_802_3);
431 		}
432 		if (!fr_hard_header(&skb, pvc->dlci)) {
433 			dev->stats.tx_bytes += skb->len;
434 			dev->stats.tx_packets++;
435 			if (pvc->state.fecn) /* TX Congestion counter */
436 				dev->stats.tx_compressed++;
437 			skb->dev = pvc->frad;
438 			dev_queue_xmit(skb);
439 			return 0;
440 		}
441 	}
442 
443 	dev->stats.tx_dropped++;
444 	dev_kfree_skb(skb);
445 	return 0;
446 }
447 
448 
449 
450 static int pvc_change_mtu(struct net_device *dev, int new_mtu)
451 {
452 	if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
453 		return -EINVAL;
454 	dev->mtu = new_mtu;
455 	return 0;
456 }
457 
458 
459 
460 static inline void fr_log_dlci_active(pvc_device *pvc)
461 {
462 	printk(KERN_INFO "%s: DLCI %d [%s%s%s]%s %s\n",
463 	       pvc->frad->name,
464 	       pvc->dlci,
465 	       pvc->main ? pvc->main->name : "",
466 	       pvc->main && pvc->ether ? " " : "",
467 	       pvc->ether ? pvc->ether->name : "",
468 	       pvc->state.new ? " new" : "",
469 	       !pvc->state.exist ? "deleted" :
470 	       pvc->state.active ? "active" : "inactive");
471 }
472 
473 
474 
475 static inline u8 fr_lmi_nextseq(u8 x)
476 {
477 	x++;
478 	return x ? x : 1;
479 }
480 
481 
482 static void fr_lmi_send(struct net_device *dev, int fullrep)
483 {
484 	hdlc_device *hdlc = dev_to_hdlc(dev);
485 	struct sk_buff *skb;
486 	pvc_device *pvc = state(hdlc)->first_pvc;
487 	int lmi = state(hdlc)->settings.lmi;
488 	int dce = state(hdlc)->settings.dce;
489 	int len = lmi == LMI_ANSI ? LMI_ANSI_LENGTH : LMI_CCITT_CISCO_LENGTH;
490 	int stat_len = (lmi == LMI_CISCO) ? 6 : 3;
491 	u8 *data;
492 	int i = 0;
493 
494 	if (dce && fullrep) {
495 		len += state(hdlc)->dce_pvc_count * (2 + stat_len);
496 		if (len > HDLC_MAX_MRU) {
497 			printk(KERN_WARNING "%s: Too many PVCs while sending "
498 			       "LMI full report\n", dev->name);
499 			return;
500 		}
501 	}
502 
503 	skb = dev_alloc_skb(len);
504 	if (!skb) {
505 		printk(KERN_WARNING "%s: Memory squeeze on fr_lmi_send()\n",
506 		       dev->name);
507 		return;
508 	}
509 	memset(skb->data, 0, len);
510 	skb_reserve(skb, 4);
511 	if (lmi == LMI_CISCO) {
512 		skb->protocol = __constant_htons(NLPID_CISCO_LMI);
513 		fr_hard_header(&skb, LMI_CISCO_DLCI);
514 	} else {
515 		skb->protocol = __constant_htons(NLPID_CCITT_ANSI_LMI);
516 		fr_hard_header(&skb, LMI_CCITT_ANSI_DLCI);
517 	}
518 	data = skb_tail_pointer(skb);
519 	data[i++] = LMI_CALLREF;
520 	data[i++] = dce ? LMI_STATUS : LMI_STATUS_ENQUIRY;
521 	if (lmi == LMI_ANSI)
522 		data[i++] = LMI_ANSI_LOCKSHIFT;
523 	data[i++] = lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
524 		LMI_ANSI_CISCO_REPTYPE;
525 	data[i++] = LMI_REPT_LEN;
526 	data[i++] = fullrep ? LMI_FULLREP : LMI_INTEGRITY;
527 	data[i++] = lmi == LMI_CCITT ? LMI_CCITT_ALIVE : LMI_ANSI_CISCO_ALIVE;
528 	data[i++] = LMI_INTEG_LEN;
529 	data[i++] = state(hdlc)->txseq =
530 		fr_lmi_nextseq(state(hdlc)->txseq);
531 	data[i++] = state(hdlc)->rxseq;
532 
533 	if (dce && fullrep) {
534 		while (pvc) {
535 			data[i++] = lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
536 				LMI_ANSI_CISCO_PVCSTAT;
537 			data[i++] = stat_len;
538 
539 			/* LMI start/restart */
540 			if (state(hdlc)->reliable && !pvc->state.exist) {
541 				pvc->state.exist = pvc->state.new = 1;
542 				fr_log_dlci_active(pvc);
543 			}
544 
545 			/* ifconfig PVC up */
546 			if (pvc->open_count && !pvc->state.active &&
547 			    pvc->state.exist && !pvc->state.new) {
548 				pvc_carrier(1, pvc);
549 				pvc->state.active = 1;
550 				fr_log_dlci_active(pvc);
551 			}
552 
553 			if (lmi == LMI_CISCO) {
554 				data[i] = pvc->dlci >> 8;
555 				data[i + 1] = pvc->dlci & 0xFF;
556 			} else {
557 				data[i] = (pvc->dlci >> 4) & 0x3F;
558 				data[i + 1] = ((pvc->dlci << 3) & 0x78) | 0x80;
559 				data[i + 2] = 0x80;
560 			}
561 
562 			if (pvc->state.new)
563 				data[i + 2] |= 0x08;
564 			else if (pvc->state.active)
565 				data[i + 2] |= 0x02;
566 
567 			i += stat_len;
568 			pvc = pvc->next;
569 		}
570 	}
571 
572 	skb_put(skb, i);
573 	skb->priority = TC_PRIO_CONTROL;
574 	skb->dev = dev;
575 	skb_reset_network_header(skb);
576 
577 	dev_queue_xmit(skb);
578 }
579 
580 
581 
582 static void fr_set_link_state(int reliable, struct net_device *dev)
583 {
584 	hdlc_device *hdlc = dev_to_hdlc(dev);
585 	pvc_device *pvc = state(hdlc)->first_pvc;
586 
587 	state(hdlc)->reliable = reliable;
588 	if (reliable) {
589 		netif_dormant_off(dev);
590 		state(hdlc)->n391cnt = 0; /* Request full status */
591 		state(hdlc)->dce_changed = 1;
592 
593 		if (state(hdlc)->settings.lmi == LMI_NONE) {
594 			while (pvc) {	/* Activate all PVCs */
595 				pvc_carrier(1, pvc);
596 				pvc->state.exist = pvc->state.active = 1;
597 				pvc->state.new = 0;
598 				pvc = pvc->next;
599 			}
600 		}
601 	} else {
602 		netif_dormant_on(dev);
603 		while (pvc) {		/* Deactivate all PVCs */
604 			pvc_carrier(0, pvc);
605 			pvc->state.exist = pvc->state.active = 0;
606 			pvc->state.new = 0;
607 			if (!state(hdlc)->settings.dce)
608 				pvc->state.bandwidth = 0;
609 			pvc = pvc->next;
610 		}
611 	}
612 }
613 
614 
615 static void fr_timer(unsigned long arg)
616 {
617 	struct net_device *dev = (struct net_device *)arg;
618 	hdlc_device *hdlc = dev_to_hdlc(dev);
619 	int i, cnt = 0, reliable;
620 	u32 list;
621 
622 	if (state(hdlc)->settings.dce) {
623 		reliable = state(hdlc)->request &&
624 			time_before(jiffies, state(hdlc)->last_poll +
625 				    state(hdlc)->settings.t392 * HZ);
626 		state(hdlc)->request = 0;
627 	} else {
628 		state(hdlc)->last_errors <<= 1; /* Shift the list */
629 		if (state(hdlc)->request) {
630 			if (state(hdlc)->reliable)
631 				printk(KERN_INFO "%s: No LMI status reply "
632 				       "received\n", dev->name);
633 			state(hdlc)->last_errors |= 1;
634 		}
635 
636 		list = state(hdlc)->last_errors;
637 		for (i = 0; i < state(hdlc)->settings.n393; i++, list >>= 1)
638 			cnt += (list & 1);	/* errors count */
639 
640 		reliable = (cnt < state(hdlc)->settings.n392);
641 	}
642 
643 	if (state(hdlc)->reliable != reliable) {
644 		printk(KERN_INFO "%s: Link %sreliable\n", dev->name,
645 		       reliable ? "" : "un");
646 		fr_set_link_state(reliable, dev);
647 	}
648 
649 	if (state(hdlc)->settings.dce)
650 		state(hdlc)->timer.expires = jiffies +
651 			state(hdlc)->settings.t392 * HZ;
652 	else {
653 		if (state(hdlc)->n391cnt)
654 			state(hdlc)->n391cnt--;
655 
656 		fr_lmi_send(dev, state(hdlc)->n391cnt == 0);
657 
658 		state(hdlc)->last_poll = jiffies;
659 		state(hdlc)->request = 1;
660 		state(hdlc)->timer.expires = jiffies +
661 			state(hdlc)->settings.t391 * HZ;
662 	}
663 
664 	state(hdlc)->timer.function = fr_timer;
665 	state(hdlc)->timer.data = arg;
666 	add_timer(&state(hdlc)->timer);
667 }
668 
669 
670 static int fr_lmi_recv(struct net_device *dev, struct sk_buff *skb)
671 {
672 	hdlc_device *hdlc = dev_to_hdlc(dev);
673 	pvc_device *pvc;
674 	u8 rxseq, txseq;
675 	int lmi = state(hdlc)->settings.lmi;
676 	int dce = state(hdlc)->settings.dce;
677 	int stat_len = (lmi == LMI_CISCO) ? 6 : 3, reptype, error, no_ram, i;
678 
679 	if (skb->len < (lmi == LMI_ANSI ? LMI_ANSI_LENGTH :
680 			LMI_CCITT_CISCO_LENGTH)) {
681 		printk(KERN_INFO "%s: Short LMI frame\n", dev->name);
682 		return 1;
683 	}
684 
685 	if (skb->data[3] != (lmi == LMI_CISCO ? NLPID_CISCO_LMI :
686 			     NLPID_CCITT_ANSI_LMI)) {
687 		printk(KERN_INFO "%s: Received non-LMI frame with LMI DLCI\n",
688 		       dev->name);
689 		return 1;
690 	}
691 
692 	if (skb->data[4] != LMI_CALLREF) {
693 		printk(KERN_INFO "%s: Invalid LMI Call reference (0x%02X)\n",
694 		       dev->name, skb->data[4]);
695 		return 1;
696 	}
697 
698 	if (skb->data[5] != (dce ? LMI_STATUS_ENQUIRY : LMI_STATUS)) {
699 		printk(KERN_INFO "%s: Invalid LMI Message type (0x%02X)\n",
700 		       dev->name, skb->data[5]);
701 		return 1;
702 	}
703 
704 	if (lmi == LMI_ANSI) {
705 		if (skb->data[6] != LMI_ANSI_LOCKSHIFT) {
706 			printk(KERN_INFO "%s: Not ANSI locking shift in LMI"
707 			       " message (0x%02X)\n", dev->name, skb->data[6]);
708 			return 1;
709 		}
710 		i = 7;
711 	} else
712 		i = 6;
713 
714 	if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
715 			     LMI_ANSI_CISCO_REPTYPE)) {
716 		printk(KERN_INFO "%s: Not an LMI Report type IE (0x%02X)\n",
717 		       dev->name, skb->data[i]);
718 		return 1;
719 	}
720 
721 	if (skb->data[++i] != LMI_REPT_LEN) {
722 		printk(KERN_INFO "%s: Invalid LMI Report type IE length"
723 		       " (%u)\n", dev->name, skb->data[i]);
724 		return 1;
725 	}
726 
727 	reptype = skb->data[++i];
728 	if (reptype != LMI_INTEGRITY && reptype != LMI_FULLREP) {
729 		printk(KERN_INFO "%s: Unsupported LMI Report type (0x%02X)\n",
730 		       dev->name, reptype);
731 		return 1;
732 	}
733 
734 	if (skb->data[++i] != (lmi == LMI_CCITT ? LMI_CCITT_ALIVE :
735 			       LMI_ANSI_CISCO_ALIVE)) {
736 		printk(KERN_INFO "%s: Not an LMI Link integrity verification"
737 		       " IE (0x%02X)\n", dev->name, skb->data[i]);
738 		return 1;
739 	}
740 
741 	if (skb->data[++i] != LMI_INTEG_LEN) {
742 		printk(KERN_INFO "%s: Invalid LMI Link integrity verification"
743 		       " IE length (%u)\n", dev->name, skb->data[i]);
744 		return 1;
745 	}
746 	i++;
747 
748 	state(hdlc)->rxseq = skb->data[i++]; /* TX sequence from peer */
749 	rxseq = skb->data[i++];	/* Should confirm our sequence */
750 
751 	txseq = state(hdlc)->txseq;
752 
753 	if (dce)
754 		state(hdlc)->last_poll = jiffies;
755 
756 	error = 0;
757 	if (!state(hdlc)->reliable)
758 		error = 1;
759 
760 	if (rxseq == 0 || rxseq != txseq) { /* Ask for full report next time */
761 		state(hdlc)->n391cnt = 0;
762 		error = 1;
763 	}
764 
765 	if (dce) {
766 		if (state(hdlc)->fullrep_sent && !error) {
767 /* Stop sending full report - the last one has been confirmed by DTE */
768 			state(hdlc)->fullrep_sent = 0;
769 			pvc = state(hdlc)->first_pvc;
770 			while (pvc) {
771 				if (pvc->state.new) {
772 					pvc->state.new = 0;
773 
774 /* Tell DTE that new PVC is now active */
775 					state(hdlc)->dce_changed = 1;
776 				}
777 				pvc = pvc->next;
778 			}
779 		}
780 
781 		if (state(hdlc)->dce_changed) {
782 			reptype = LMI_FULLREP;
783 			state(hdlc)->fullrep_sent = 1;
784 			state(hdlc)->dce_changed = 0;
785 		}
786 
787 		state(hdlc)->request = 1; /* got request */
788 		fr_lmi_send(dev, reptype == LMI_FULLREP ? 1 : 0);
789 		return 0;
790 	}
791 
792 	/* DTE */
793 
794 	state(hdlc)->request = 0; /* got response, no request pending */
795 
796 	if (error)
797 		return 0;
798 
799 	if (reptype != LMI_FULLREP)
800 		return 0;
801 
802 	pvc = state(hdlc)->first_pvc;
803 
804 	while (pvc) {
805 		pvc->state.deleted = 1;
806 		pvc = pvc->next;
807 	}
808 
809 	no_ram = 0;
810 	while (skb->len >= i + 2 + stat_len) {
811 		u16 dlci;
812 		u32 bw;
813 		unsigned int active, new;
814 
815 		if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
816 				       LMI_ANSI_CISCO_PVCSTAT)) {
817 			printk(KERN_INFO "%s: Not an LMI PVC status IE"
818 			       " (0x%02X)\n", dev->name, skb->data[i]);
819 			return 1;
820 		}
821 
822 		if (skb->data[++i] != stat_len) {
823 			printk(KERN_INFO "%s: Invalid LMI PVC status IE length"
824 			       " (%u)\n", dev->name, skb->data[i]);
825 			return 1;
826 		}
827 		i++;
828 
829 		new = !! (skb->data[i + 2] & 0x08);
830 		active = !! (skb->data[i + 2] & 0x02);
831 		if (lmi == LMI_CISCO) {
832 			dlci = (skb->data[i] << 8) | skb->data[i + 1];
833 			bw = (skb->data[i + 3] << 16) |
834 				(skb->data[i + 4] << 8) |
835 				(skb->data[i + 5]);
836 		} else {
837 			dlci = ((skb->data[i] & 0x3F) << 4) |
838 				((skb->data[i + 1] & 0x78) >> 3);
839 			bw = 0;
840 		}
841 
842 		pvc = add_pvc(dev, dlci);
843 
844 		if (!pvc && !no_ram) {
845 			printk(KERN_WARNING
846 			       "%s: Memory squeeze on fr_lmi_recv()\n",
847 			       dev->name);
848 			no_ram = 1;
849 		}
850 
851 		if (pvc) {
852 			pvc->state.exist = 1;
853 			pvc->state.deleted = 0;
854 			if (active != pvc->state.active ||
855 			    new != pvc->state.new ||
856 			    bw != pvc->state.bandwidth ||
857 			    !pvc->state.exist) {
858 				pvc->state.new = new;
859 				pvc->state.active = active;
860 				pvc->state.bandwidth = bw;
861 				pvc_carrier(active, pvc);
862 				fr_log_dlci_active(pvc);
863 			}
864 		}
865 
866 		i += stat_len;
867 	}
868 
869 	pvc = state(hdlc)->first_pvc;
870 
871 	while (pvc) {
872 		if (pvc->state.deleted && pvc->state.exist) {
873 			pvc_carrier(0, pvc);
874 			pvc->state.active = pvc->state.new = 0;
875 			pvc->state.exist = 0;
876 			pvc->state.bandwidth = 0;
877 			fr_log_dlci_active(pvc);
878 		}
879 		pvc = pvc->next;
880 	}
881 
882 	/* Next full report after N391 polls */
883 	state(hdlc)->n391cnt = state(hdlc)->settings.n391;
884 
885 	return 0;
886 }
887 
888 
889 static int fr_rx(struct sk_buff *skb)
890 {
891 	struct net_device *frad = skb->dev;
892 	hdlc_device *hdlc = dev_to_hdlc(frad);
893 	fr_hdr *fh = (fr_hdr*)skb->data;
894 	u8 *data = skb->data;
895 	u16 dlci;
896 	pvc_device *pvc;
897 	struct net_device *dev = NULL;
898 
899 	if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI)
900 		goto rx_error;
901 
902 	dlci = q922_to_dlci(skb->data);
903 
904 	if ((dlci == LMI_CCITT_ANSI_DLCI &&
905 	     (state(hdlc)->settings.lmi == LMI_ANSI ||
906 	      state(hdlc)->settings.lmi == LMI_CCITT)) ||
907 	    (dlci == LMI_CISCO_DLCI &&
908 	     state(hdlc)->settings.lmi == LMI_CISCO)) {
909 		if (fr_lmi_recv(frad, skb))
910 			goto rx_error;
911 		dev_kfree_skb_any(skb);
912 		return NET_RX_SUCCESS;
913 	}
914 
915 	pvc = find_pvc(hdlc, dlci);
916 	if (!pvc) {
917 #ifdef DEBUG_PKT
918 		printk(KERN_INFO "%s: No PVC for received frame's DLCI %d\n",
919 		       frad->name, dlci);
920 #endif
921 		dev_kfree_skb_any(skb);
922 		return NET_RX_DROP;
923 	}
924 
925 	if (pvc->state.fecn != fh->fecn) {
926 #ifdef DEBUG_ECN
927 		printk(KERN_DEBUG "%s: DLCI %d FECN O%s\n", frad->name,
928 		       dlci, fh->fecn ? "N" : "FF");
929 #endif
930 		pvc->state.fecn ^= 1;
931 	}
932 
933 	if (pvc->state.becn != fh->becn) {
934 #ifdef DEBUG_ECN
935 		printk(KERN_DEBUG "%s: DLCI %d BECN O%s\n", frad->name,
936 		       dlci, fh->becn ? "N" : "FF");
937 #endif
938 		pvc->state.becn ^= 1;
939 	}
940 
941 
942 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
943 		frad->stats.rx_dropped++;
944 		return NET_RX_DROP;
945 	}
946 
947 	if (data[3] == NLPID_IP) {
948 		skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
949 		dev = pvc->main;
950 		skb->protocol = htons(ETH_P_IP);
951 
952 	} else if (data[3] == NLPID_IPV6) {
953 		skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
954 		dev = pvc->main;
955 		skb->protocol = htons(ETH_P_IPV6);
956 
957 	} else if (skb->len > 10 && data[3] == FR_PAD &&
958 		   data[4] == NLPID_SNAP && data[5] == FR_PAD) {
959 		u16 oui = ntohs(*(__be16*)(data + 6));
960 		u16 pid = ntohs(*(__be16*)(data + 8));
961 		skb_pull(skb, 10);
962 
963 		switch ((((u32)oui) << 16) | pid) {
964 		case ETH_P_ARP: /* routed frame with SNAP */
965 		case ETH_P_IPX:
966 		case ETH_P_IP:	/* a long variant */
967 		case ETH_P_IPV6:
968 			dev = pvc->main;
969 			skb->protocol = htons(pid);
970 			break;
971 
972 		case 0x80C20007: /* bridged Ethernet frame */
973 			if ((dev = pvc->ether) != NULL)
974 				skb->protocol = eth_type_trans(skb, dev);
975 			break;
976 
977 		default:
978 			printk(KERN_INFO "%s: Unsupported protocol, OUI=%x "
979 			       "PID=%x\n", frad->name, oui, pid);
980 			dev_kfree_skb_any(skb);
981 			return NET_RX_DROP;
982 		}
983 	} else {
984 		printk(KERN_INFO "%s: Unsupported protocol, NLPID=%x "
985 		       "length = %i\n", frad->name, data[3], skb->len);
986 		dev_kfree_skb_any(skb);
987 		return NET_RX_DROP;
988 	}
989 
990 	if (dev) {
991 		dev->stats.rx_packets++; /* PVC traffic */
992 		dev->stats.rx_bytes += skb->len;
993 		if (pvc->state.becn)
994 			dev->stats.rx_compressed++;
995 		skb->dev = dev;
996 		netif_rx(skb);
997 		return NET_RX_SUCCESS;
998 	} else {
999 		dev_kfree_skb_any(skb);
1000 		return NET_RX_DROP;
1001 	}
1002 
1003  rx_error:
1004 	frad->stats.rx_errors++; /* Mark error */
1005 	dev_kfree_skb_any(skb);
1006 	return NET_RX_DROP;
1007 }
1008 
1009 
1010 
1011 static void fr_start(struct net_device *dev)
1012 {
1013 	hdlc_device *hdlc = dev_to_hdlc(dev);
1014 #ifdef DEBUG_LINK
1015 	printk(KERN_DEBUG "fr_start\n");
1016 #endif
1017 	if (state(hdlc)->settings.lmi != LMI_NONE) {
1018 		state(hdlc)->reliable = 0;
1019 		state(hdlc)->dce_changed = 1;
1020 		state(hdlc)->request = 0;
1021 		state(hdlc)->fullrep_sent = 0;
1022 		state(hdlc)->last_errors = 0xFFFFFFFF;
1023 		state(hdlc)->n391cnt = 0;
1024 		state(hdlc)->txseq = state(hdlc)->rxseq = 0;
1025 
1026 		init_timer(&state(hdlc)->timer);
1027 		/* First poll after 1 s */
1028 		state(hdlc)->timer.expires = jiffies + HZ;
1029 		state(hdlc)->timer.function = fr_timer;
1030 		state(hdlc)->timer.data = (unsigned long)dev;
1031 		add_timer(&state(hdlc)->timer);
1032 	} else
1033 		fr_set_link_state(1, dev);
1034 }
1035 
1036 
1037 static void fr_stop(struct net_device *dev)
1038 {
1039 	hdlc_device *hdlc = dev_to_hdlc(dev);
1040 #ifdef DEBUG_LINK
1041 	printk(KERN_DEBUG "fr_stop\n");
1042 #endif
1043 	if (state(hdlc)->settings.lmi != LMI_NONE)
1044 		del_timer_sync(&state(hdlc)->timer);
1045 	fr_set_link_state(0, dev);
1046 }
1047 
1048 
1049 static void fr_close(struct net_device *dev)
1050 {
1051 	hdlc_device *hdlc = dev_to_hdlc(dev);
1052 	pvc_device *pvc = state(hdlc)->first_pvc;
1053 
1054 	while (pvc) {		/* Shutdown all PVCs for this FRAD */
1055 		if (pvc->main)
1056 			dev_close(pvc->main);
1057 		if (pvc->ether)
1058 			dev_close(pvc->ether);
1059 		pvc = pvc->next;
1060 	}
1061 }
1062 
1063 
1064 static void pvc_setup(struct net_device *dev)
1065 {
1066 	dev->type = ARPHRD_DLCI;
1067 	dev->flags = IFF_POINTOPOINT;
1068 	dev->hard_header_len = 10;
1069 	dev->addr_len = 2;
1070 }
1071 
1072 static int fr_add_pvc(struct net_device *frad, unsigned int dlci, int type)
1073 {
1074 	hdlc_device *hdlc = dev_to_hdlc(frad);
1075 	pvc_device *pvc;
1076 	struct net_device *dev;
1077 	int result, used;
1078 
1079 	if ((pvc = add_pvc(frad, dlci)) == NULL) {
1080 		printk(KERN_WARNING "%s: Memory squeeze on fr_add_pvc()\n",
1081 		       frad->name);
1082 		return -ENOBUFS;
1083 	}
1084 
1085 	if (*get_dev_p(pvc, type))
1086 		return -EEXIST;
1087 
1088 	used = pvc_is_used(pvc);
1089 
1090 	if (type == ARPHRD_ETHER)
1091 		dev = alloc_netdev(0, "pvceth%d", ether_setup);
1092 	else
1093 		dev = alloc_netdev(0, "pvc%d", pvc_setup);
1094 
1095 	if (!dev) {
1096 		printk(KERN_WARNING "%s: Memory squeeze on fr_pvc()\n",
1097 		       frad->name);
1098 		delete_unused_pvcs(hdlc);
1099 		return -ENOBUFS;
1100 	}
1101 
1102 	if (type == ARPHRD_ETHER)
1103 		random_ether_addr(dev->dev_addr);
1104 	else {
1105 		*(__be16*)dev->dev_addr = htons(dlci);
1106 		dlci_to_q922(dev->broadcast, dlci);
1107 	}
1108 	dev->hard_start_xmit = pvc_xmit;
1109 	dev->open = pvc_open;
1110 	dev->stop = pvc_close;
1111 	dev->do_ioctl = pvc_ioctl;
1112 	dev->change_mtu = pvc_change_mtu;
1113 	dev->mtu = HDLC_MAX_MTU;
1114 	dev->tx_queue_len = 0;
1115 	dev->priv = pvc;
1116 
1117 	result = dev_alloc_name(dev, dev->name);
1118 	if (result < 0) {
1119 		free_netdev(dev);
1120 		delete_unused_pvcs(hdlc);
1121 		return result;
1122 	}
1123 
1124 	if (register_netdevice(dev) != 0) {
1125 		free_netdev(dev);
1126 		delete_unused_pvcs(hdlc);
1127 		return -EIO;
1128 	}
1129 
1130 	dev->destructor = free_netdev;
1131 	*get_dev_p(pvc, type) = dev;
1132 	if (!used) {
1133 		state(hdlc)->dce_changed = 1;
1134 		state(hdlc)->dce_pvc_count++;
1135 	}
1136 	return 0;
1137 }
1138 
1139 
1140 
1141 static int fr_del_pvc(hdlc_device *hdlc, unsigned int dlci, int type)
1142 {
1143 	pvc_device *pvc;
1144 	struct net_device *dev;
1145 
1146 	if ((pvc = find_pvc(hdlc, dlci)) == NULL)
1147 		return -ENOENT;
1148 
1149 	if ((dev = *get_dev_p(pvc, type)) == NULL)
1150 		return -ENOENT;
1151 
1152 	if (dev->flags & IFF_UP)
1153 		return -EBUSY;		/* PVC in use */
1154 
1155 	unregister_netdevice(dev); /* the destructor will free_netdev(dev) */
1156 	*get_dev_p(pvc, type) = NULL;
1157 
1158 	if (!pvc_is_used(pvc)) {
1159 		state(hdlc)->dce_pvc_count--;
1160 		state(hdlc)->dce_changed = 1;
1161 	}
1162 	delete_unused_pvcs(hdlc);
1163 	return 0;
1164 }
1165 
1166 
1167 
1168 static void fr_destroy(struct net_device *frad)
1169 {
1170 	hdlc_device *hdlc = dev_to_hdlc(frad);
1171 	pvc_device *pvc = state(hdlc)->first_pvc;
1172 	state(hdlc)->first_pvc = NULL; /* All PVCs destroyed */
1173 	state(hdlc)->dce_pvc_count = 0;
1174 	state(hdlc)->dce_changed = 1;
1175 
1176 	while (pvc) {
1177 		pvc_device *next = pvc->next;
1178 		/* destructors will free_netdev() main and ether */
1179 		if (pvc->main)
1180 			unregister_netdevice(pvc->main);
1181 
1182 		if (pvc->ether)
1183 			unregister_netdevice(pvc->ether);
1184 
1185 		kfree(pvc);
1186 		pvc = next;
1187 	}
1188 }
1189 
1190 
1191 static struct hdlc_proto proto = {
1192 	.close		= fr_close,
1193 	.start		= fr_start,
1194 	.stop		= fr_stop,
1195 	.detach		= fr_destroy,
1196 	.ioctl		= fr_ioctl,
1197 	.netif_rx	= fr_rx,
1198 	.module		= THIS_MODULE,
1199 };
1200 
1201 
1202 static int fr_ioctl(struct net_device *dev, struct ifreq *ifr)
1203 {
1204 	fr_proto __user *fr_s = ifr->ifr_settings.ifs_ifsu.fr;
1205 	const size_t size = sizeof(fr_proto);
1206 	fr_proto new_settings;
1207 	hdlc_device *hdlc = dev_to_hdlc(dev);
1208 	fr_proto_pvc pvc;
1209 	int result;
1210 
1211 	switch (ifr->ifr_settings.type) {
1212 	case IF_GET_PROTO:
1213 		if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
1214 			return -EINVAL;
1215 		ifr->ifr_settings.type = IF_PROTO_FR;
1216 		if (ifr->ifr_settings.size < size) {
1217 			ifr->ifr_settings.size = size; /* data size wanted */
1218 			return -ENOBUFS;
1219 		}
1220 		if (copy_to_user(fr_s, &state(hdlc)->settings, size))
1221 			return -EFAULT;
1222 		return 0;
1223 
1224 	case IF_PROTO_FR:
1225 		if(!capable(CAP_NET_ADMIN))
1226 			return -EPERM;
1227 
1228 		if(dev->flags & IFF_UP)
1229 			return -EBUSY;
1230 
1231 		if (copy_from_user(&new_settings, fr_s, size))
1232 			return -EFAULT;
1233 
1234 		if (new_settings.lmi == LMI_DEFAULT)
1235 			new_settings.lmi = LMI_ANSI;
1236 
1237 		if ((new_settings.lmi != LMI_NONE &&
1238 		     new_settings.lmi != LMI_ANSI &&
1239 		     new_settings.lmi != LMI_CCITT &&
1240 		     new_settings.lmi != LMI_CISCO) ||
1241 		    new_settings.t391 < 1 ||
1242 		    new_settings.t392 < 2 ||
1243 		    new_settings.n391 < 1 ||
1244 		    new_settings.n392 < 1 ||
1245 		    new_settings.n393 < new_settings.n392 ||
1246 		    new_settings.n393 > 32 ||
1247 		    (new_settings.dce != 0 &&
1248 		     new_settings.dce != 1))
1249 			return -EINVAL;
1250 
1251 		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
1252 		if (result)
1253 			return result;
1254 
1255 		if (dev_to_hdlc(dev)->proto != &proto) { /* Different proto */
1256 			result = attach_hdlc_protocol(dev, &proto,
1257 						      sizeof(struct frad_state));
1258 			if (result)
1259 				return result;
1260 			state(hdlc)->first_pvc = NULL;
1261 			state(hdlc)->dce_pvc_count = 0;
1262 		}
1263 		memcpy(&state(hdlc)->settings, &new_settings, size);
1264 
1265 		dev->hard_start_xmit = hdlc->xmit;
1266 		dev->type = ARPHRD_FRAD;
1267 		return 0;
1268 
1269 	case IF_PROTO_FR_ADD_PVC:
1270 	case IF_PROTO_FR_DEL_PVC:
1271 	case IF_PROTO_FR_ADD_ETH_PVC:
1272 	case IF_PROTO_FR_DEL_ETH_PVC:
1273 		if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
1274 			return -EINVAL;
1275 
1276 		if(!capable(CAP_NET_ADMIN))
1277 			return -EPERM;
1278 
1279 		if (copy_from_user(&pvc, ifr->ifr_settings.ifs_ifsu.fr_pvc,
1280 				   sizeof(fr_proto_pvc)))
1281 			return -EFAULT;
1282 
1283 		if (pvc.dlci <= 0 || pvc.dlci >= 1024)
1284 			return -EINVAL;	/* Only 10 bits, DLCI 0 reserved */
1285 
1286 		if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC ||
1287 		    ifr->ifr_settings.type == IF_PROTO_FR_DEL_ETH_PVC)
1288 			result = ARPHRD_ETHER; /* bridged Ethernet device */
1289 		else
1290 			result = ARPHRD_DLCI;
1291 
1292 		if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_PVC ||
1293 		    ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC)
1294 			return fr_add_pvc(dev, pvc.dlci, result);
1295 		else
1296 			return fr_del_pvc(hdlc, pvc.dlci, result);
1297 	}
1298 
1299 	return -EINVAL;
1300 }
1301 
1302 
1303 static int __init mod_init(void)
1304 {
1305 	register_hdlc_protocol(&proto);
1306 	return 0;
1307 }
1308 
1309 
1310 static void __exit mod_exit(void)
1311 {
1312 	unregister_hdlc_protocol(&proto);
1313 }
1314 
1315 
1316 module_init(mod_init);
1317 module_exit(mod_exit);
1318 
1319 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
1320 MODULE_DESCRIPTION("Frame-Relay protocol support for generic HDLC");
1321 MODULE_LICENSE("GPL v2");
1322