1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Generic HDLC support routines for Linux
  4 * Point-to-point protocol support
  5 *
  6 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
  7 */
  8
  9#include <linux/errno.h>
 10#include <linux/hdlc.h>
 11#include <linux/if_arp.h>
 12#include <linux/inetdevice.h>
 13#include <linux/init.h>
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/pkt_sched.h>
 17#include <linux/poll.h>
 18#include <linux/skbuff.h>
 19#include <linux/slab.h>
 20#include <linux/spinlock.h>
 21
 22#define DEBUG_CP		0 /* also bytes# to dump */
 23#define DEBUG_STATE		0
 24#define DEBUG_HARD_HEADER	0
 25
 26#define HDLC_ADDR_ALLSTATIONS	0xFF
 27#define HDLC_CTRL_UI		0x03
 28
 29#define PID_LCP			0xC021
 30#define PID_IP			0x0021
 31#define PID_IPCP		0x8021
 32#define PID_IPV6		0x0057
 33#define PID_IPV6CP		0x8057
 34
 35enum {IDX_LCP = 0, IDX_IPCP, IDX_IPV6CP, IDX_COUNT};
 36enum {CP_CONF_REQ = 1, CP_CONF_ACK, CP_CONF_NAK, CP_CONF_REJ, CP_TERM_REQ,
 37      CP_TERM_ACK, CP_CODE_REJ, LCP_PROTO_REJ, LCP_ECHO_REQ, LCP_ECHO_REPLY,
 38      LCP_DISC_REQ, CP_CODES};
 39#if DEBUG_CP
 40static const char *const code_names[CP_CODES] = {
 41	"0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
 42	"TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
 43};
 44
 45static char debug_buffer[64 + 3 * DEBUG_CP];
 46#endif
 47
 48enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
 49
 50struct hdlc_header {
 51	u8 address;
 52	u8 control;
 53	__be16 protocol;
 54};
 55
 56struct cp_header {
 57	u8 code;
 58	u8 id;
 59	__be16 len;
 60};
 61
 62struct proto {
 63	struct net_device *dev;
 64	struct timer_list timer;
 65	unsigned long timeout;
 66	u16 pid;		/* protocol ID */
 67	u8 state;
 68	u8 cr_id;		/* ID of last Configuration-Request */
 69	u8 restart_counter;
 70};
 71
 72struct ppp {
 73	struct proto protos[IDX_COUNT];
 74	spinlock_t lock;
 75	unsigned long last_pong;
 76	unsigned int req_timeout, cr_retries, term_retries;
 77	unsigned int keepalive_interval, keepalive_timeout;
 78	u8 seq;			/* local sequence number for requests */
 79	u8 echo_id;		/* ID of last Echo-Request (LCP) */
 80};
 81
 82enum {CLOSED = 0, STOPPED, STOPPING, REQ_SENT, ACK_RECV, ACK_SENT, OPENED,
 83      STATES, STATE_MASK = 0xF};
 84enum {START = 0, STOP, TO_GOOD, TO_BAD, RCR_GOOD, RCR_BAD, RCA, RCN, RTR, RTA,
 85      RUC, RXJ_GOOD, RXJ_BAD, EVENTS};
 86enum {INV = 0x10, IRC = 0x20, ZRC = 0x40, SCR = 0x80, SCA = 0x100,
 87      SCN = 0x200, STR = 0x400, STA = 0x800, SCJ = 0x1000};
 88
 89#if DEBUG_STATE
 90static const char *const state_names[STATES] = {
 91	"Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
 92	"Opened"
 93};
 94
 95static const char *const event_names[EVENTS] = {
 96	"Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
 97	"RTR", "RTA", "RUC", "RXJ+", "RXJ-"
 98};
 99#endif
100
101static struct sk_buff_head tx_queue; /* used when holding the spin lock */
102
103static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs);
104
105static inline struct ppp *get_ppp(struct net_device *dev)
106{
107	return (struct ppp *)dev_to_hdlc(dev)->state;
108}
109
110static inline struct proto *get_proto(struct net_device *dev, u16 pid)
111{
112	struct ppp *ppp = get_ppp(dev);
113
114	switch (pid) {
115	case PID_LCP:
116		return &ppp->protos[IDX_LCP];
117	case PID_IPCP:
118		return &ppp->protos[IDX_IPCP];
119	case PID_IPV6CP:
120		return &ppp->protos[IDX_IPV6CP];
121	default:
122		return NULL;
123	}
124}
125
126static inline const char *proto_name(u16 pid)
127{
128	switch (pid) {
129	case PID_LCP:
130		return "LCP";
131	case PID_IPCP:
132		return "IPCP";
133	case PID_IPV6CP:
134		return "IPV6CP";
135	default:
136		return NULL;
137	}
138}
139
140static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
141{
142	struct hdlc_header *data = (struct hdlc_header *)skb->data;
143
144	if (skb->len < sizeof(struct hdlc_header))
145		return htons(ETH_P_HDLC);
146	if (data->address != HDLC_ADDR_ALLSTATIONS ||
147	    data->control != HDLC_CTRL_UI)
148		return htons(ETH_P_HDLC);
149
150	switch (data->protocol) {
151	case cpu_to_be16(PID_IP):
152		skb_pull(skb, sizeof(struct hdlc_header));
153		return htons(ETH_P_IP);
154
155	case cpu_to_be16(PID_IPV6):
156		skb_pull(skb, sizeof(struct hdlc_header));
157		return htons(ETH_P_IPV6);
158
159	default:
160		return htons(ETH_P_HDLC);
161	}
162}
163
164static int ppp_hard_header(struct sk_buff *skb, struct net_device *dev,
165			   u16 type, const void *daddr, const void *saddr,
166			   unsigned int len)
167{
168	struct hdlc_header *data;
169#if DEBUG_HARD_HEADER
170	printk(KERN_DEBUG "%s: ppp_hard_header() called\n", dev->name);
171#endif
172
173	skb_push(skb, sizeof(struct hdlc_header));
174	data = (struct hdlc_header *)skb->data;
175
176	data->address = HDLC_ADDR_ALLSTATIONS;
177	data->control = HDLC_CTRL_UI;
178	switch (type) {
179	case ETH_P_IP:
180		data->protocol = htons(PID_IP);
181		break;
182	case ETH_P_IPV6:
183		data->protocol = htons(PID_IPV6);
184		break;
185	case PID_LCP:
186	case PID_IPCP:
187	case PID_IPV6CP:
188		data->protocol = htons(type);
189		break;
190	default:		/* unknown protocol */
191		data->protocol = 0;
192	}
193	return sizeof(struct hdlc_header);
194}
195
196static void ppp_tx_flush(void)
197{
198	struct sk_buff *skb;
199
200	while ((skb = skb_dequeue(&tx_queue)) != NULL)
201		dev_queue_xmit(skb);
202}
203
204static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
205		      u8 id, unsigned int len, const void *data)
206{
207	struct sk_buff *skb;
208	struct cp_header *cp;
209	unsigned int magic_len = 0;
210	static u32 magic;
211
212#if DEBUG_CP
213	int i;
214	char *ptr;
215#endif
216
217	if (pid == PID_LCP && (code == LCP_ECHO_REQ || code == LCP_ECHO_REPLY))
218		magic_len = sizeof(magic);
219
220	skb = dev_alloc_skb(sizeof(struct hdlc_header) +
221			    sizeof(struct cp_header) + magic_len + len);
222	if (!skb)
223		return;
224
225	skb_reserve(skb, sizeof(struct hdlc_header));
226
227	cp = skb_put(skb, sizeof(struct cp_header));
228	cp->code = code;
229	cp->id = id;
230	cp->len = htons(sizeof(struct cp_header) + magic_len + len);
231
232	if (magic_len)
233		skb_put_data(skb, &magic, magic_len);
234	if (len)
235		skb_put_data(skb, data, len);
236
237#if DEBUG_CP
238	BUG_ON(code >= CP_CODES);
239	ptr = debug_buffer;
240	*ptr = '\x0';
241	for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
242		sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
243		ptr += strlen(ptr);
244	}
245	printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
246	       proto_name(pid), code_names[code], id, debug_buffer);
247#endif
248
249	ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
250
251	skb->priority = TC_PRIO_CONTROL;
252	skb->dev = dev;
253	skb->protocol = htons(ETH_P_HDLC);
254	skb_reset_network_header(skb);
255	skb_queue_tail(&tx_queue, skb);
256}
257
258/* State transition table (compare STD-51)
259   Events                                   Actions
260   TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
261   TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
262
263   RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
264   RCR- = Receive-Configure-Request (Bad)
265   RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
266   RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
267
268   RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
269   RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
270
271   RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
272   RXJ+ = Receive-Code-Reject (permitted)
273       or Receive-Protocol-Reject
274   RXJ- = Receive-Code-Reject (catastrophic)
275       or Receive-Protocol-Reject
276*/
277static int cp_table[EVENTS][STATES] = {
278	/* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
279	     0           1         2       3       4      5          6    */
280	{IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
281	{   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
282	{   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
283	{   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
284	{  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
285	{  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
286	{  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
287	{  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
288	{  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
289	{    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
290	{  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
291	{    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
292	{    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
293};
294
295/* SCA: RCR+ must supply id, len and data
296   SCN: RCR- must supply code, id, len and data
297   STA: RTR must supply id
298   SCJ: RUC must supply CP packet len and data */
299static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
300			 u8 id, unsigned int len, const void *data)
301{
302	int old_state, action;
303	struct ppp *ppp = get_ppp(dev);
304	struct proto *proto = get_proto(dev, pid);
305
306	old_state = proto->state;
307	BUG_ON(old_state >= STATES);
308	BUG_ON(event >= EVENTS);
309
310#if DEBUG_STATE
311	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
312	       proto_name(pid), event_names[event], state_names[proto->state]);
313#endif
314
315	action = cp_table[event][old_state];
316
317	proto->state = action & STATE_MASK;
318	if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
319		mod_timer(&proto->timer, proto->timeout =
320			  jiffies + ppp->req_timeout * HZ);
321	if (action & ZRC)
322		proto->restart_counter = 0;
323	if (action & IRC)
324		proto->restart_counter = (proto->state == STOPPING) ?
325			ppp->term_retries : ppp->cr_retries;
326
327	if (action & SCR)	/* send Configure-Request */
328		ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
329			  0, NULL);
330	if (action & SCA)	/* send Configure-Ack */
331		ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
332	if (action & SCN)	/* send Configure-Nak/Reject */
333		ppp_tx_cp(dev, pid, code, id, len, data);
334	if (action & STR)	/* send Terminate-Request */
335		ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
336	if (action & STA)	/* send Terminate-Ack */
337		ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
338	if (action & SCJ)	/* send Code-Reject */
339		ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
340
341	if (old_state != OPENED && proto->state == OPENED) {
342		netdev_info(dev, "%s up\n", proto_name(pid));
343		if (pid == PID_LCP) {
344			netif_dormant_off(dev);
345			ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
346			ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
347			ppp->last_pong = jiffies;
348			mod_timer(&proto->timer, proto->timeout =
349				  jiffies + ppp->keepalive_interval * HZ);
350		}
351	}
352	if (old_state == OPENED && proto->state != OPENED) {
353		netdev_info(dev, "%s down\n", proto_name(pid));
354		if (pid == PID_LCP) {
355			netif_dormant_on(dev);
356			ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
357			ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
358		}
359	}
360	if (old_state != CLOSED && proto->state == CLOSED)
361		del_timer(&proto->timer);
362
363#if DEBUG_STATE
364	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
365	       proto_name(pid), event_names[event], state_names[proto->state]);
366#endif
367}
368
369static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
370			    unsigned int req_len, const u8 *data)
371{
372	static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
373	const u8 *opt;
374	u8 *out;
375	unsigned int len = req_len, nak_len = 0, rej_len = 0;
376
377	out = kmalloc(len, GFP_ATOMIC);
378	if (!out) {
379		dev->stats.rx_dropped++;
380		return;	/* out of memory, ignore CR packet */
381	}
382
383	for (opt = data; len; len -= opt[1], opt += opt[1]) {
384		if (len < 2 || opt[1] < 2 || len < opt[1])
385			goto err_out;
386
387		if (pid == PID_LCP)
388			switch (opt[0]) {
389			case LCP_OPTION_MRU:
390				continue; /* MRU always OK and > 1500 bytes? */
391
392			case LCP_OPTION_ACCM: /* async control character map */
393				if (opt[1] < sizeof(valid_accm))
394					goto err_out;
395				if (!memcmp(opt, valid_accm,
396					    sizeof(valid_accm)))
397					continue;
398				if (!rej_len) { /* NAK it */
399					memcpy(out + nak_len, valid_accm,
400					       sizeof(valid_accm));
401					nak_len += sizeof(valid_accm);
402					continue;
403				}
404				break;
405			case LCP_OPTION_MAGIC:
406				if (len < 6)
407					goto err_out;
408				if (opt[1] != 6 || (!opt[2] && !opt[3] &&
409						    !opt[4] && !opt[5]))
410					break; /* reject invalid magic number */
411				continue;
412			}
413		/* reject this option */
414		memcpy(out + rej_len, opt, opt[1]);
415		rej_len += opt[1];
416	}
417
418	if (rej_len)
419		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
420	else if (nak_len)
421		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
422	else
423		ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
424
425	kfree(out);
426	return;
427
428err_out:
429	dev->stats.rx_errors++;
430	kfree(out);
431}
432
433static int ppp_rx(struct sk_buff *skb)
434{
435	struct hdlc_header *hdr = (struct hdlc_header *)skb->data;
436	struct net_device *dev = skb->dev;
437	struct ppp *ppp = get_ppp(dev);
438	struct proto *proto;
439	struct cp_header *cp;
440	unsigned long flags;
441	unsigned int len;
442	u16 pid;
443#if DEBUG_CP
444	int i;
445	char *ptr;
446#endif
447
448	spin_lock_irqsave(&ppp->lock, flags);
449	/* Check HDLC header */
450	if (skb->len < sizeof(struct hdlc_header))
451		goto rx_error;
452	cp = skb_pull(skb, sizeof(struct hdlc_header));
453	if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
454	    hdr->control != HDLC_CTRL_UI)
455		goto rx_error;
456
457	pid = ntohs(hdr->protocol);
458	proto = get_proto(dev, pid);
459	if (!proto) {
460		if (ppp->protos[IDX_LCP].state == OPENED)
461			ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
462				  ++ppp->seq, skb->len + 2, &hdr->protocol);
463		goto rx_error;
464	}
465
466	len = ntohs(cp->len);
467	if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
468	    skb->len < len /* truncated packet? */)
469		goto rx_error;
470	skb_pull(skb, sizeof(struct cp_header));
471	len -= sizeof(struct cp_header);
472
473	/* HDLC and CP headers stripped from skb */
474#if DEBUG_CP
475	if (cp->code < CP_CODES)
476		sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
477			cp->id);
478	else
479		sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
480	ptr = debug_buffer + strlen(debug_buffer);
481	for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
482		sprintf(ptr, " %02X", skb->data[i]);
483		ptr += strlen(ptr);
484	}
485	printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
486	       debug_buffer);
487#endif
488
489	/* LCP only */
490	if (pid == PID_LCP)
491		switch (cp->code) {
492		case LCP_PROTO_REJ:
493			pid = ntohs(*(__be16 *)skb->data);
494			if (pid == PID_LCP || pid == PID_IPCP ||
495			    pid == PID_IPV6CP)
496				ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
497					     0, NULL);
498			goto out;
499
500		case LCP_ECHO_REQ: /* send Echo-Reply */
501			if (len >= 4 && proto->state == OPENED)
502				ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
503					  cp->id, len - 4, skb->data + 4);
504			goto out;
505
506		case LCP_ECHO_REPLY:
507			if (cp->id == ppp->echo_id)
508				ppp->last_pong = jiffies;
509			goto out;
510
511		case LCP_DISC_REQ: /* discard */
512			goto out;
513		}
514
515	/* LCP, IPCP and IPV6CP */
516	switch (cp->code) {
517	case CP_CONF_REQ:
518		ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
519		break;
520
521	case CP_CONF_ACK:
522		if (cp->id == proto->cr_id)
523			ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
524		break;
525
526	case CP_CONF_REJ:
527	case CP_CONF_NAK:
528		if (cp->id == proto->cr_id)
529			ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
530		break;
531
532	case CP_TERM_REQ:
533		ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
534		break;
535
536	case CP_TERM_ACK:
537		ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
538		break;
539
540	case CP_CODE_REJ:
541		ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
542		break;
543
544	default:
545		len += sizeof(struct cp_header);
546		if (len > dev->mtu)
547			len = dev->mtu;
548		ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
549		break;
550	}
551	goto out;
552
553rx_error:
554	dev->stats.rx_errors++;
555out:
556	spin_unlock_irqrestore(&ppp->lock, flags);
557	dev_kfree_skb_any(skb);
558	ppp_tx_flush();
559	return NET_RX_DROP;
560}
561
562static void ppp_timer(struct timer_list *t)
563{
564	struct proto *proto = from_timer(proto, t, timer);
565	struct ppp *ppp = get_ppp(proto->dev);
566	unsigned long flags;
567
568	spin_lock_irqsave(&ppp->lock, flags);
569	/* mod_timer could be called after we entered this function but
570	 * before we got the lock.
571	 */
572	if (timer_pending(&proto->timer)) {
573		spin_unlock_irqrestore(&ppp->lock, flags);
574		return;
575	}
576	switch (proto->state) {
577	case STOPPING:
578	case REQ_SENT:
579	case ACK_RECV:
580	case ACK_SENT:
581		if (proto->restart_counter) {
582			ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
583				     0, NULL);
584			proto->restart_counter--;
585		} else if (netif_carrier_ok(proto->dev))
586			ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
587				     0, NULL);
588		else
589			ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
590				     0, NULL);
591		break;
592
593	case OPENED:
594		if (proto->pid != PID_LCP)
595			break;
596		if (time_after(jiffies, ppp->last_pong +
597			       ppp->keepalive_timeout * HZ)) {
598			netdev_info(proto->dev, "Link down\n");
599			ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
600			ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
601		} else {	/* send keep-alive packet */
602			ppp->echo_id = ++ppp->seq;
603			ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
604				  ppp->echo_id, 0, NULL);
605			proto->timer.expires = jiffies +
606				ppp->keepalive_interval * HZ;
607			add_timer(&proto->timer);
608		}
609		break;
610	}
611	spin_unlock_irqrestore(&ppp->lock, flags);
612	ppp_tx_flush();
613}
614
615static void ppp_start(struct net_device *dev)
616{
617	struct ppp *ppp = get_ppp(dev);
618	int i;
619
620	for (i = 0; i < IDX_COUNT; i++) {
621		struct proto *proto = &ppp->protos[i];
622
623		proto->dev = dev;
624		timer_setup(&proto->timer, ppp_timer, 0);
625		proto->state = CLOSED;
626	}
627	ppp->protos[IDX_LCP].pid = PID_LCP;
628	ppp->protos[IDX_IPCP].pid = PID_IPCP;
629	ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
630
631	ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
632}
633
634static void ppp_stop(struct net_device *dev)
635{
636	ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
637}
638
639static void ppp_close(struct net_device *dev)
640{
641	ppp_tx_flush();
642}
643
644static struct hdlc_proto proto = {
645	.start		= ppp_start,
646	.stop		= ppp_stop,
647	.close		= ppp_close,
648	.type_trans	= ppp_type_trans,
649	.ioctl		= ppp_ioctl,
650	.netif_rx	= ppp_rx,
651	.module		= THIS_MODULE,
652};
653
654static const struct header_ops ppp_header_ops = {
655	.create = ppp_hard_header,
656};
657
658static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs)
659{
660	hdlc_device *hdlc = dev_to_hdlc(dev);
661	struct ppp *ppp;
662	int result;
663
664	switch (ifs->type) {
665	case IF_GET_PROTO:
666		if (dev_to_hdlc(dev)->proto != &proto)
667			return -EINVAL;
668		ifs->type = IF_PROTO_PPP;
669		return 0; /* return protocol only, no settable parameters */
670
671	case IF_PROTO_PPP:
672		if (!capable(CAP_NET_ADMIN))
673			return -EPERM;
674
675		if (dev->flags & IFF_UP)
676			return -EBUSY;
677
678		/* no settable parameters */
679
680		result = hdlc->attach(dev, ENCODING_NRZ,
681				      PARITY_CRC16_PR1_CCITT);
682		if (result)
683			return result;
684
685		result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
686		if (result)
687			return result;
688
689		ppp = get_ppp(dev);
690		spin_lock_init(&ppp->lock);
691		ppp->req_timeout = 2;
692		ppp->cr_retries = 10;
693		ppp->term_retries = 2;
694		ppp->keepalive_interval = 10;
695		ppp->keepalive_timeout = 60;
696
697		dev->hard_header_len = sizeof(struct hdlc_header);
698		dev->header_ops = &ppp_header_ops;
699		dev->type = ARPHRD_PPP;
700		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
701		netif_dormant_on(dev);
702		return 0;
703	}
704
705	return -EINVAL;
706}
707
708static int __init hdlc_ppp_init(void)
709{
710	skb_queue_head_init(&tx_queue);
711	register_hdlc_protocol(&proto);
712	return 0;
713}
714
715static void __exit hdlc_ppp_exit(void)
716{
717	unregister_hdlc_protocol(&proto);
718}
719
720module_init(hdlc_ppp_init);
721module_exit(hdlc_ppp_exit);
722
723MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
724MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
725MODULE_LICENSE("GPL v2");