xref: /openbmc/linux/drivers/net/wan/hdlc_ppp.c (revision 588b48ca)
1 /*
2  * Generic HDLC support routines for Linux
3  * Point-to-point protocol support
4  *
5  * Copyright (C) 1999 - 2008 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/skbuff.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24 
25 #define DEBUG_CP		0 /* also bytes# to dump */
26 #define DEBUG_STATE		0
27 #define DEBUG_HARD_HEADER	0
28 
29 #define HDLC_ADDR_ALLSTATIONS	0xFF
30 #define HDLC_CTRL_UI		0x03
31 
32 #define PID_LCP			0xC021
33 #define PID_IP			0x0021
34 #define PID_IPCP		0x8021
35 #define PID_IPV6		0x0057
36 #define PID_IPV6CP		0x8057
37 
38 enum {IDX_LCP = 0, IDX_IPCP, IDX_IPV6CP, IDX_COUNT};
39 enum {CP_CONF_REQ = 1, CP_CONF_ACK, CP_CONF_NAK, CP_CONF_REJ, CP_TERM_REQ,
40       CP_TERM_ACK, CP_CODE_REJ, LCP_PROTO_REJ, LCP_ECHO_REQ, LCP_ECHO_REPLY,
41       LCP_DISC_REQ, CP_CODES};
42 #if DEBUG_CP
43 static const char *const code_names[CP_CODES] = {
44 	"0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
45 	"TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
46 };
47 static char debug_buffer[64 + 3 * DEBUG_CP];
48 #endif
49 
50 enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
51 
52 struct hdlc_header {
53 	u8 address;
54 	u8 control;
55 	__be16 protocol;
56 };
57 
58 struct cp_header {
59 	u8 code;
60 	u8 id;
61 	__be16 len;
62 };
63 
64 
65 struct proto {
66 	struct net_device *dev;
67 	struct timer_list timer;
68 	unsigned long timeout;
69 	u16 pid;		/* protocol ID */
70 	u8 state;
71 	u8 cr_id;		/* ID of last Configuration-Request */
72 	u8 restart_counter;
73 };
74 
75 struct ppp {
76 	struct proto protos[IDX_COUNT];
77 	spinlock_t lock;
78 	unsigned long last_pong;
79 	unsigned int req_timeout, cr_retries, term_retries;
80 	unsigned int keepalive_interval, keepalive_timeout;
81 	u8 seq;			/* local sequence number for requests */
82 	u8 echo_id;		/* ID of last Echo-Request (LCP) */
83 };
84 
85 enum {CLOSED = 0, STOPPED, STOPPING, REQ_SENT, ACK_RECV, ACK_SENT, OPENED,
86       STATES, STATE_MASK = 0xF};
87 enum {START = 0, STOP, TO_GOOD, TO_BAD, RCR_GOOD, RCR_BAD, RCA, RCN, RTR, RTA,
88       RUC, RXJ_GOOD, RXJ_BAD, EVENTS};
89 enum {INV = 0x10, IRC = 0x20, ZRC = 0x40, SCR = 0x80, SCA = 0x100,
90       SCN = 0x200, STR = 0x400, STA = 0x800, SCJ = 0x1000};
91 
92 #if DEBUG_STATE
93 static const char *const state_names[STATES] = {
94 	"Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
95 	"Opened"
96 };
97 static const char *const event_names[EVENTS] = {
98 	"Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
99 	"RTR", "RTA", "RUC", "RXJ+", "RXJ-"
100 };
101 #endif
102 
103 static struct sk_buff_head tx_queue; /* used when holding the spin lock */
104 
105 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
106 
107 static inline struct ppp* get_ppp(struct net_device *dev)
108 {
109 	return (struct ppp *)dev_to_hdlc(dev)->state;
110 }
111 
112 static inline struct proto* get_proto(struct net_device *dev, u16 pid)
113 {
114 	struct ppp *ppp = get_ppp(dev);
115 
116 	switch (pid) {
117 	case PID_LCP:
118 		return &ppp->protos[IDX_LCP];
119 	case PID_IPCP:
120 		return &ppp->protos[IDX_IPCP];
121 	case PID_IPV6CP:
122 		return &ppp->protos[IDX_IPV6CP];
123 	default:
124 		return NULL;
125 	}
126 }
127 
128 static inline const char* proto_name(u16 pid)
129 {
130 	switch (pid) {
131 	case PID_LCP:
132 		return "LCP";
133 	case PID_IPCP:
134 		return "IPCP";
135 	case PID_IPV6CP:
136 		return "IPV6CP";
137 	default:
138 		return NULL;
139 	}
140 }
141 
142 static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
143 {
144 	struct hdlc_header *data = (struct hdlc_header*)skb->data;
145 
146 	if (skb->len < sizeof(struct hdlc_header))
147 		return htons(ETH_P_HDLC);
148 	if (data->address != HDLC_ADDR_ALLSTATIONS ||
149 	    data->control != HDLC_CTRL_UI)
150 		return htons(ETH_P_HDLC);
151 
152 	switch (data->protocol) {
153 	case cpu_to_be16(PID_IP):
154 		skb_pull(skb, sizeof(struct hdlc_header));
155 		return htons(ETH_P_IP);
156 
157 	case cpu_to_be16(PID_IPV6):
158 		skb_pull(skb, sizeof(struct hdlc_header));
159 		return htons(ETH_P_IPV6);
160 
161 	default:
162 		return htons(ETH_P_HDLC);
163 	}
164 }
165 
166 
167 static int ppp_hard_header(struct sk_buff *skb, struct net_device *dev,
168 			   u16 type, const void *daddr, const void *saddr,
169 			   unsigned int len)
170 {
171 	struct hdlc_header *data;
172 #if DEBUG_HARD_HEADER
173 	printk(KERN_DEBUG "%s: ppp_hard_header() called\n", dev->name);
174 #endif
175 
176 	skb_push(skb, sizeof(struct hdlc_header));
177 	data = (struct hdlc_header*)skb->data;
178 
179 	data->address = HDLC_ADDR_ALLSTATIONS;
180 	data->control = HDLC_CTRL_UI;
181 	switch (type) {
182 	case ETH_P_IP:
183 		data->protocol = htons(PID_IP);
184 		break;
185 	case ETH_P_IPV6:
186 		data->protocol = htons(PID_IPV6);
187 		break;
188 	case PID_LCP:
189 	case PID_IPCP:
190 	case PID_IPV6CP:
191 		data->protocol = htons(type);
192 		break;
193 	default:		/* unknown protocol */
194 		data->protocol = 0;
195 	}
196 	return sizeof(struct hdlc_header);
197 }
198 
199 
200 static void ppp_tx_flush(void)
201 {
202 	struct sk_buff *skb;
203 	while ((skb = skb_dequeue(&tx_queue)) != NULL)
204 		dev_queue_xmit(skb);
205 }
206 
207 static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
208 		      u8 id, unsigned int len, const void *data)
209 {
210 	struct sk_buff *skb;
211 	struct cp_header *cp;
212 	unsigned int magic_len = 0;
213 	static u32 magic;
214 
215 #if DEBUG_CP
216 	int i;
217 	char *ptr;
218 #endif
219 
220 	if (pid == PID_LCP && (code == LCP_ECHO_REQ || code == LCP_ECHO_REPLY))
221 		magic_len = sizeof(magic);
222 
223 	skb = dev_alloc_skb(sizeof(struct hdlc_header) +
224 			    sizeof(struct cp_header) + magic_len + len);
225 	if (!skb) {
226 		netdev_warn(dev, "out of memory in ppp_tx_cp()\n");
227 		return;
228 	}
229 	skb_reserve(skb, sizeof(struct hdlc_header));
230 
231 	cp = (struct cp_header *)skb_put(skb, sizeof(struct cp_header));
232 	cp->code = code;
233 	cp->id = id;
234 	cp->len = htons(sizeof(struct cp_header) + magic_len + len);
235 
236 	if (magic_len)
237 		memcpy(skb_put(skb, magic_len), &magic, magic_len);
238 	if (len)
239 		memcpy(skb_put(skb, len), data, len);
240 
241 #if DEBUG_CP
242 	BUG_ON(code >= CP_CODES);
243 	ptr = debug_buffer;
244 	*ptr = '\x0';
245 	for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
246 		sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
247 		ptr += strlen(ptr);
248 	}
249 	printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
250 	       proto_name(pid), code_names[code], id, debug_buffer);
251 #endif
252 
253 	ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
254 
255 	skb->priority = TC_PRIO_CONTROL;
256 	skb->dev = dev;
257 	skb_reset_network_header(skb);
258 	skb_queue_tail(&tx_queue, skb);
259 }
260 
261 
262 /* State transition table (compare STD-51)
263    Events                                   Actions
264    TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
265    TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
266 
267    RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
268    RCR- = Receive-Configure-Request (Bad)
269    RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
270    RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
271 
272    RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
273    RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
274 
275    RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
276    RXJ+ = Receive-Code-Reject (permitted)
277        or Receive-Protocol-Reject
278    RXJ- = Receive-Code-Reject (catastrophic)
279        or Receive-Protocol-Reject
280 */
281 static int cp_table[EVENTS][STATES] = {
282 	/* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
283 	     0           1         2       3       4      5          6    */
284 	{IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
285 	{   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
286 	{   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
287 	{   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
288 	{  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
289 	{  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
290 	{  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
291 	{  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
292 	{  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
293 	{    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
294 	{  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
295 	{    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
296 	{    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
297 };
298 
299 
300 /* SCA: RCR+ must supply id, len and data
301    SCN: RCR- must supply code, id, len and data
302    STA: RTR must supply id
303    SCJ: RUC must supply CP packet len and data */
304 static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
305 			 u8 id, unsigned int len, const void *data)
306 {
307 	int old_state, action;
308 	struct ppp *ppp = get_ppp(dev);
309 	struct proto *proto = get_proto(dev, pid);
310 
311 	old_state = proto->state;
312 	BUG_ON(old_state >= STATES);
313 	BUG_ON(event >= EVENTS);
314 
315 #if DEBUG_STATE
316 	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
317 	       proto_name(pid), event_names[event], state_names[proto->state]);
318 #endif
319 
320 	action = cp_table[event][old_state];
321 
322 	proto->state = action & STATE_MASK;
323 	if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
324 		mod_timer(&proto->timer, proto->timeout =
325 			  jiffies + ppp->req_timeout * HZ);
326 	if (action & ZRC)
327 		proto->restart_counter = 0;
328 	if (action & IRC)
329 		proto->restart_counter = (proto->state == STOPPING) ?
330 			ppp->term_retries : ppp->cr_retries;
331 
332 	if (action & SCR)	/* send Configure-Request */
333 		ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
334 			  0, NULL);
335 	if (action & SCA)	/* send Configure-Ack */
336 		ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
337 	if (action & SCN)	/* send Configure-Nak/Reject */
338 		ppp_tx_cp(dev, pid, code, id, len, data);
339 	if (action & STR)	/* send Terminate-Request */
340 		ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
341 	if (action & STA)	/* send Terminate-Ack */
342 		ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
343 	if (action & SCJ)	/* send Code-Reject */
344 		ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
345 
346 	if (old_state != OPENED && proto->state == OPENED) {
347 		netdev_info(dev, "%s up\n", proto_name(pid));
348 		if (pid == PID_LCP) {
349 			netif_dormant_off(dev);
350 			ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
351 			ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
352 			ppp->last_pong = jiffies;
353 			mod_timer(&proto->timer, proto->timeout =
354 				  jiffies + ppp->keepalive_interval * HZ);
355 		}
356 	}
357 	if (old_state == OPENED && proto->state != OPENED) {
358 		netdev_info(dev, "%s down\n", proto_name(pid));
359 		if (pid == PID_LCP) {
360 			netif_dormant_on(dev);
361 			ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
362 			ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
363 		}
364 	}
365 	if (old_state != CLOSED && proto->state == CLOSED)
366 		del_timer(&proto->timer);
367 
368 #if DEBUG_STATE
369 	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
370 	       proto_name(pid), event_names[event], state_names[proto->state]);
371 #endif
372 }
373 
374 
375 static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
376 			    unsigned int req_len, const u8 *data)
377 {
378 	static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
379 	const u8 *opt;
380 	u8 *out;
381 	unsigned int len = req_len, nak_len = 0, rej_len = 0;
382 
383 	if (!(out = kmalloc(len, GFP_ATOMIC))) {
384 		dev->stats.rx_dropped++;
385 		return;	/* out of memory, ignore CR packet */
386 	}
387 
388 	for (opt = data; len; len -= opt[1], opt += opt[1]) {
389 		if (len < 2 || len < opt[1]) {
390 			dev->stats.rx_errors++;
391 			kfree(out);
392 			return; /* bad packet, drop silently */
393 		}
394 
395 		if (pid == PID_LCP)
396 			switch (opt[0]) {
397 			case LCP_OPTION_MRU:
398 				continue; /* MRU always OK and > 1500 bytes? */
399 
400 			case LCP_OPTION_ACCM: /* async control character map */
401 				if (!memcmp(opt, valid_accm,
402 					    sizeof(valid_accm)))
403 					continue;
404 				if (!rej_len) { /* NAK it */
405 					memcpy(out + nak_len, valid_accm,
406 					       sizeof(valid_accm));
407 					nak_len += sizeof(valid_accm);
408 					continue;
409 				}
410 				break;
411 			case LCP_OPTION_MAGIC:
412 				if (opt[1] != 6 || (!opt[2] && !opt[3] &&
413 						    !opt[4] && !opt[5]))
414 					break; /* reject invalid magic number */
415 				continue;
416 			}
417 		/* reject this option */
418 		memcpy(out + rej_len, opt, opt[1]);
419 		rej_len += opt[1];
420 	}
421 
422 	if (rej_len)
423 		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
424 	else if (nak_len)
425 		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
426 	else
427 		ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
428 
429 	kfree(out);
430 }
431 
432 static int ppp_rx(struct sk_buff *skb)
433 {
434 	struct hdlc_header *hdr = (struct hdlc_header*)skb->data;
435 	struct net_device *dev = skb->dev;
436 	struct ppp *ppp = get_ppp(dev);
437 	struct proto *proto;
438 	struct cp_header *cp;
439 	unsigned long flags;
440 	unsigned int len;
441 	u16 pid;
442 #if DEBUG_CP
443 	int i;
444 	char *ptr;
445 #endif
446 
447 	spin_lock_irqsave(&ppp->lock, flags);
448 	/* Check HDLC header */
449 	if (skb->len < sizeof(struct hdlc_header))
450 		goto rx_error;
451 	cp = (struct cp_header*)skb_pull(skb, sizeof(struct hdlc_header));
452 	if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
453 	    hdr->control != HDLC_CTRL_UI)
454 		goto rx_error;
455 
456 	pid = ntohs(hdr->protocol);
457 	proto = get_proto(dev, pid);
458 	if (!proto) {
459 		if (ppp->protos[IDX_LCP].state == OPENED)
460 			ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
461 				  ++ppp->seq, skb->len + 2, &hdr->protocol);
462 		goto rx_error;
463 	}
464 
465 	len = ntohs(cp->len);
466 	if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
467 	    skb->len < len /* truncated packet? */)
468 		goto rx_error;
469 	skb_pull(skb, sizeof(struct cp_header));
470 	len -= sizeof(struct cp_header);
471 
472 	/* HDLC and CP headers stripped from skb */
473 #if DEBUG_CP
474 	if (cp->code < CP_CODES)
475 		sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
476 			cp->id);
477 	else
478 		sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
479 	ptr = debug_buffer + strlen(debug_buffer);
480 	for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
481 		sprintf(ptr, " %02X", skb->data[i]);
482 		ptr += strlen(ptr);
483 	}
484 	printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
485 	       debug_buffer);
486 #endif
487 
488 	/* LCP only */
489 	if (pid == PID_LCP)
490 		switch (cp->code) {
491 		case LCP_PROTO_REJ:
492 			pid = ntohs(*(__be16*)skb->data);
493 			if (pid == PID_LCP || pid == PID_IPCP ||
494 			    pid == PID_IPV6CP)
495 				ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
496 					     0, NULL);
497 			goto out;
498 
499 		case LCP_ECHO_REQ: /* send Echo-Reply */
500 			if (len >= 4 && proto->state == OPENED)
501 				ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
502 					  cp->id, len - 4, skb->data + 4);
503 			goto out;
504 
505 		case LCP_ECHO_REPLY:
506 			if (cp->id == ppp->echo_id)
507 				ppp->last_pong = jiffies;
508 			goto out;
509 
510 		case LCP_DISC_REQ: /* discard */
511 			goto out;
512 		}
513 
514 	/* LCP, IPCP and IPV6CP */
515 	switch (cp->code) {
516 	case CP_CONF_REQ:
517 		ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
518 		break;
519 
520 	case CP_CONF_ACK:
521 		if (cp->id == proto->cr_id)
522 			ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
523 		break;
524 
525 	case CP_CONF_REJ:
526 	case CP_CONF_NAK:
527 		if (cp->id == proto->cr_id)
528 			ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
529 		break;
530 
531 	case CP_TERM_REQ:
532 		ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
533 		break;
534 
535 	case CP_TERM_ACK:
536 		ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
537 		break;
538 
539 	case CP_CODE_REJ:
540 		ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
541 		break;
542 
543 	default:
544 		len += sizeof(struct cp_header);
545 		if (len > dev->mtu)
546 			len = dev->mtu;
547 		ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
548 		break;
549 	}
550 	goto out;
551 
552 rx_error:
553 	dev->stats.rx_errors++;
554 out:
555 	spin_unlock_irqrestore(&ppp->lock, flags);
556 	dev_kfree_skb_any(skb);
557 	ppp_tx_flush();
558 	return NET_RX_DROP;
559 }
560 
561 static void ppp_timer(unsigned long arg)
562 {
563 	struct proto *proto = (struct proto *)arg;
564 	struct ppp *ppp = get_ppp(proto->dev);
565 	unsigned long flags;
566 
567 	spin_lock_irqsave(&ppp->lock, flags);
568 	switch (proto->state) {
569 	case STOPPING:
570 	case REQ_SENT:
571 	case ACK_RECV:
572 	case ACK_SENT:
573 		if (proto->restart_counter) {
574 			ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
575 				     0, NULL);
576 			proto->restart_counter--;
577 		} else
578 			ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
579 				     0, NULL);
580 		break;
581 
582 	case OPENED:
583 		if (proto->pid != PID_LCP)
584 			break;
585 		if (time_after(jiffies, ppp->last_pong +
586 			       ppp->keepalive_timeout * HZ)) {
587 			netdev_info(proto->dev, "Link down\n");
588 			ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
589 			ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
590 		} else {	/* send keep-alive packet */
591 			ppp->echo_id = ++ppp->seq;
592 			ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
593 				  ppp->echo_id, 0, NULL);
594 			proto->timer.expires = jiffies +
595 				ppp->keepalive_interval * HZ;
596 			add_timer(&proto->timer);
597 		}
598 		break;
599 	}
600 	spin_unlock_irqrestore(&ppp->lock, flags);
601 	ppp_tx_flush();
602 }
603 
604 
605 static void ppp_start(struct net_device *dev)
606 {
607 	struct ppp *ppp = get_ppp(dev);
608 	int i;
609 
610 	for (i = 0; i < IDX_COUNT; i++) {
611 		struct proto *proto = &ppp->protos[i];
612 		proto->dev = dev;
613 		init_timer(&proto->timer);
614 		proto->timer.function = ppp_timer;
615 		proto->timer.data = (unsigned long)proto;
616 		proto->state = CLOSED;
617 	}
618 	ppp->protos[IDX_LCP].pid = PID_LCP;
619 	ppp->protos[IDX_IPCP].pid = PID_IPCP;
620 	ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
621 
622 	ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
623 }
624 
625 static void ppp_stop(struct net_device *dev)
626 {
627 	ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
628 }
629 
630 static void ppp_close(struct net_device *dev)
631 {
632 	ppp_tx_flush();
633 }
634 
635 static struct hdlc_proto proto = {
636 	.start		= ppp_start,
637 	.stop		= ppp_stop,
638 	.close		= ppp_close,
639 	.type_trans	= ppp_type_trans,
640 	.ioctl		= ppp_ioctl,
641 	.netif_rx	= ppp_rx,
642 	.module		= THIS_MODULE,
643 };
644 
645 static const struct header_ops ppp_header_ops = {
646 	.create = ppp_hard_header,
647 };
648 
649 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr)
650 {
651 	hdlc_device *hdlc = dev_to_hdlc(dev);
652 	struct ppp *ppp;
653 	int result;
654 
655 	switch (ifr->ifr_settings.type) {
656 	case IF_GET_PROTO:
657 		if (dev_to_hdlc(dev)->proto != &proto)
658 			return -EINVAL;
659 		ifr->ifr_settings.type = IF_PROTO_PPP;
660 		return 0; /* return protocol only, no settable parameters */
661 
662 	case IF_PROTO_PPP:
663 		if (!capable(CAP_NET_ADMIN))
664 			return -EPERM;
665 
666 		if (dev->flags & IFF_UP)
667 			return -EBUSY;
668 
669 		/* no settable parameters */
670 
671 		result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
672 		if (result)
673 			return result;
674 
675 		result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
676 		if (result)
677 			return result;
678 
679 		ppp = get_ppp(dev);
680 		spin_lock_init(&ppp->lock);
681 		ppp->req_timeout = 2;
682 		ppp->cr_retries = 10;
683 		ppp->term_retries = 2;
684 		ppp->keepalive_interval = 10;
685 		ppp->keepalive_timeout = 60;
686 
687 		dev->hard_header_len = sizeof(struct hdlc_header);
688 		dev->header_ops = &ppp_header_ops;
689 		dev->type = ARPHRD_PPP;
690 		netif_dormant_on(dev);
691 		return 0;
692 	}
693 
694 	return -EINVAL;
695 }
696 
697 
698 static int __init mod_init(void)
699 {
700 	skb_queue_head_init(&tx_queue);
701 	register_hdlc_protocol(&proto);
702 	return 0;
703 }
704 
705 static void __exit mod_exit(void)
706 {
707 	unregister_hdlc_protocol(&proto);
708 }
709 
710 
711 module_init(mod_init);
712 module_exit(mod_exit);
713 
714 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
715 MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
716 MODULE_LICENSE("GPL v2");
717