Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 725 insertions, 0 deletions

diff --git a/drivers/net/wan/hdlc_ppp.c b/drivers/net/wan/hdlc_ppp.c
new file mode 100644
index 000000000..37a3c989c
--- /dev/null
+++ b/drivers/net/wan/hdlc_ppp.c
@@ -0,0 +1,725 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic HDLC support routines for Linux
+ * Point-to-point protocol support
+ *
+ * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
+ */
+
+#include <linux/errno.h>
+#include <linux/hdlc.h>
+#include <linux/if_arp.h>
+#include <linux/inetdevice.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pkt_sched.h>
+#include <linux/poll.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define DEBUG_CP		0 /* also bytes# to dump */
+#define DEBUG_STATE		0
+#define DEBUG_HARD_HEADER	0
+
+#define HDLC_ADDR_ALLSTATIONS	0xFF
+#define HDLC_CTRL_UI		0x03
+
+#define PID_LCP			0xC021
+#define PID_IP			0x0021
+#define PID_IPCP		0x8021
+#define PID_IPV6		0x0057
+#define PID_IPV6CP		0x8057
+
+enum {IDX_LCP = 0, IDX_IPCP, IDX_IPV6CP, IDX_COUNT};
+enum {CP_CONF_REQ = 1, CP_CONF_ACK, CP_CONF_NAK, CP_CONF_REJ, CP_TERM_REQ,
+      CP_TERM_ACK, CP_CODE_REJ, LCP_PROTO_REJ, LCP_ECHO_REQ, LCP_ECHO_REPLY,
+      LCP_DISC_REQ, CP_CODES};
+#if DEBUG_CP
+static const char *const code_names[CP_CODES] = {
+	"0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
+	"TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
+};
+
+static char debug_buffer[64 + 3 * DEBUG_CP];
+#endif
+
+enum {LCP_OPTION_MRU = 1, LCP_OPTION_ACCM, LCP_OPTION_MAGIC = 5};
+
+struct hdlc_header {
+	u8 address;
+	u8 control;
+	__be16 protocol;
+};
+
+struct cp_header {
+	u8 code;
+	u8 id;
+	__be16 len;
+};
+
+struct proto {
+	struct net_device *dev;
+	struct timer_list timer;
+	unsigned long timeout;
+	u16 pid;		/* protocol ID */
+	u8 state;
+	u8 cr_id;		/* ID of last Configuration-Request */
+	u8 restart_counter;
+};
+
+struct ppp {
+	struct proto protos[IDX_COUNT];
+	spinlock_t lock;
+	unsigned long last_pong;
+	unsigned int req_timeout, cr_retries, term_retries;
+	unsigned int keepalive_interval, keepalive_timeout;
+	u8 seq;			/* local sequence number for requests */
+	u8 echo_id;		/* ID of last Echo-Request (LCP) */
+};
+
+enum {CLOSED = 0, STOPPED, STOPPING, REQ_SENT, ACK_RECV, ACK_SENT, OPENED,
+      STATES, STATE_MASK = 0xF};
+enum {START = 0, STOP, TO_GOOD, TO_BAD, RCR_GOOD, RCR_BAD, RCA, RCN, RTR, RTA,
+      RUC, RXJ_GOOD, RXJ_BAD, EVENTS};
+enum {INV = 0x10, IRC = 0x20, ZRC = 0x40, SCR = 0x80, SCA = 0x100,
+      SCN = 0x200, STR = 0x400, STA = 0x800, SCJ = 0x1000};
+
+#if DEBUG_STATE
+static const char *const state_names[STATES] = {
+	"Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
+	"Opened"
+};
+
+static const char *const event_names[EVENTS] = {
+	"Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
+	"RTR", "RTA", "RUC", "RXJ+", "RXJ-"
+};
+#endif
+
+static struct sk_buff_head tx_queue; /* used when holding the spin lock */
+
+static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs);
+
+static inline struct ppp *get_ppp(struct net_device *dev)
+{
+	return (struct ppp *)dev_to_hdlc(dev)->state;
+}
+
+static inline struct proto *get_proto(struct net_device *dev, u16 pid)
+{
+	struct ppp *ppp = get_ppp(dev);
+
+	switch (pid) {
+	case PID_LCP:
+		return &ppp->protos[IDX_LCP];
+	case PID_IPCP:
+		return &ppp->protos[IDX_IPCP];
+	case PID_IPV6CP:
+		return &ppp->protos[IDX_IPV6CP];
+	default:
+		return NULL;
+	}
+}
+
+static inline const char *proto_name(u16 pid)
+{
+	switch (pid) {
+	case PID_LCP:
+		return "LCP";
+	case PID_IPCP:
+		return "IPCP";
+	case PID_IPV6CP:
+		return "IPV6CP";
+	default:
+		return NULL;
+	}
+}
+
+static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+	struct hdlc_header *data = (struct hdlc_header *)skb->data;
+
+	if (skb->len < sizeof(struct hdlc_header))
+		return htons(ETH_P_HDLC);
+	if (data->address != HDLC_ADDR_ALLSTATIONS ||
+	    data->control != HDLC_CTRL_UI)
+		return htons(ETH_P_HDLC);
+
+	switch (data->protocol) {
+	case cpu_to_be16(PID_IP):
+		skb_pull(skb, sizeof(struct hdlc_header));
+		return htons(ETH_P_IP);
+
+	case cpu_to_be16(PID_IPV6):
+		skb_pull(skb, sizeof(struct hdlc_header));
+		return htons(ETH_P_IPV6);
+
+	default:
+		return htons(ETH_P_HDLC);
+	}
+}
+
+static int ppp_hard_header(struct sk_buff *skb, struct net_device *dev,
+			   u16 type, const void *daddr, const void *saddr,
+			   unsigned int len)
+{
+	struct hdlc_header *data;
+#if DEBUG_HARD_HEADER
+	printk(KERN_DEBUG "%s: ppp_hard_header() called\n", dev->name);
+#endif
+
+	skb_push(skb, sizeof(struct hdlc_header));
+	data = (struct hdlc_header *)skb->data;
+
+	data->address = HDLC_ADDR_ALLSTATIONS;
+	data->control = HDLC_CTRL_UI;
+	switch (type) {
+	case ETH_P_IP:
+		data->protocol = htons(PID_IP);
+		break;
+	case ETH_P_IPV6:
+		data->protocol = htons(PID_IPV6);
+		break;
+	case PID_LCP:
+	case PID_IPCP:
+	case PID_IPV6CP:
+		data->protocol = htons(type);
+		break;
+	default:		/* unknown protocol */
+		data->protocol = 0;
+	}
+	return sizeof(struct hdlc_header);
+}
+
+static void ppp_tx_flush(void)
+{
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&tx_queue)) != NULL)
+		dev_queue_xmit(skb);
+}
+
+static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
+		      u8 id, unsigned int len, const void *data)
+{
+	struct sk_buff *skb;
+	struct cp_header *cp;
+	unsigned int magic_len = 0;
+	static u32 magic;
+
+#if DEBUG_CP
+	int i;
+	char *ptr;
+#endif
+
+	if (pid == PID_LCP && (code == LCP_ECHO_REQ || code == LCP_ECHO_REPLY))
+		magic_len = sizeof(magic);
+
+	skb = dev_alloc_skb(sizeof(struct hdlc_header) +
+			    sizeof(struct cp_header) + magic_len + len);
+	if (!skb)
+		return;
+
+	skb_reserve(skb, sizeof(struct hdlc_header));
+
+	cp = skb_put(skb, sizeof(struct cp_header));
+	cp->code = code;
+	cp->id = id;
+	cp->len = htons(sizeof(struct cp_header) + magic_len + len);
+
+	if (magic_len)
+		skb_put_data(skb, &magic, magic_len);
+	if (len)
+		skb_put_data(skb, data, len);
+
+#if DEBUG_CP
+	BUG_ON(code >= CP_CODES);
+	ptr = debug_buffer;
+	*ptr = '\x0';
+	for (i = 0; i < min_t(unsigned int, magic_len + len, DEBUG_CP); i++) {
+		sprintf(ptr, " %02X", skb->data[sizeof(struct cp_header) + i]);
+		ptr += strlen(ptr);
+	}
+	printk(KERN_DEBUG "%s: TX %s [%s id 0x%X]%s\n", dev->name,
+	       proto_name(pid), code_names[code], id, debug_buffer);
+#endif
+
+	ppp_hard_header(skb, dev, pid, NULL, NULL, 0);
+
+	skb->priority = TC_PRIO_CONTROL;
+	skb->dev = dev;
+	skb->protocol = htons(ETH_P_HDLC);
+	skb_reset_network_header(skb);
+	skb_queue_tail(&tx_queue, skb);
+}
+
+/* State transition table (compare STD-51)
+   Events                                   Actions
+   TO+  = Timeout with counter > 0          irc = Initialize-Restart-Count
+   TO-  = Timeout with counter expired      zrc = Zero-Restart-Count
+
+   RCR+ = Receive-Configure-Request (Good)  scr = Send-Configure-Request
+   RCR- = Receive-Configure-Request (Bad)
+   RCA  = Receive-Configure-Ack             sca = Send-Configure-Ack
+   RCN  = Receive-Configure-Nak/Rej         scn = Send-Configure-Nak/Rej
+
+   RTR  = Receive-Terminate-Request         str = Send-Terminate-Request
+   RTA  = Receive-Terminate-Ack             sta = Send-Terminate-Ack
+
+   RUC  = Receive-Unknown-Code              scj = Send-Code-Reject
+   RXJ+ = Receive-Code-Reject (permitted)
+       or Receive-Protocol-Reject
+   RXJ- = Receive-Code-Reject (catastrophic)
+       or Receive-Protocol-Reject
+*/
+static int cp_table[EVENTS][STATES] = {
+	/* CLOSED     STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
+	     0           1         2       3       4      5          6    */
+	{IRC|SCR|3,     INV     , INV ,   INV   , INV ,  INV    ,   INV   }, /* START */
+	{   INV   ,      0      ,  0  ,    0    ,  0  ,   0     ,    0    }, /* STOP */
+	{   INV   ,     INV     ,STR|2,  SCR|3  ,SCR|3,  SCR|5  ,   INV   }, /* TO+ */
+	{   INV   ,     INV     ,  1  ,    1    ,  1  ,    1    ,   INV   }, /* TO- */
+	{  STA|0  ,IRC|SCR|SCA|5,  2  ,  SCA|5  ,SCA|6,  SCA|5  ,SCR|SCA|5}, /* RCR+ */
+	{  STA|0  ,IRC|SCR|SCN|3,  2  ,  SCN|3  ,SCN|4,  SCN|3  ,SCR|SCN|3}, /* RCR- */
+	{  STA|0  ,    STA|1    ,  2  ,  IRC|4  ,SCR|3,    6    , SCR|3   }, /* RCA */
+	{  STA|0  ,    STA|1    ,  2  ,IRC|SCR|3,SCR|3,IRC|SCR|5, SCR|3   }, /* RCN */
+	{  STA|0  ,    STA|1    ,STA|2,  STA|3  ,STA|3,  STA|3  ,ZRC|STA|2}, /* RTR */
+	{    0    ,      1      ,  1  ,    3    ,  3  ,    5    ,  SCR|3  }, /* RTA */
+	{  SCJ|0  ,    SCJ|1    ,SCJ|2,  SCJ|3  ,SCJ|4,  SCJ|5  ,  SCJ|6  }, /* RUC */
+	{    0    ,      1      ,  2  ,    3    ,  3  ,    5    ,    6    }, /* RXJ+ */
+	{    0    ,      1      ,  1  ,    1    ,  1  ,    1    ,IRC|STR|2}, /* RXJ- */
+};
+
+/* SCA: RCR+ must supply id, len and data
+   SCN: RCR- must supply code, id, len and data
+   STA: RTR must supply id
+   SCJ: RUC must supply CP packet len and data */
+static void ppp_cp_event(struct net_device *dev, u16 pid, u16 event, u8 code,
+			 u8 id, unsigned int len, const void *data)
+{
+	int old_state, action;
+	struct ppp *ppp = get_ppp(dev);
+	struct proto *proto = get_proto(dev, pid);
+
+	old_state = proto->state;
+	BUG_ON(old_state >= STATES);
+	BUG_ON(event >= EVENTS);
+
+#if DEBUG_STATE
+	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) %s ...\n", dev->name,
+	       proto_name(pid), event_names[event], state_names[proto->state]);
+#endif
+
+	action = cp_table[event][old_state];
+
+	proto->state = action & STATE_MASK;
+	if (action & (SCR | STR)) /* set Configure-Req/Terminate-Req timer */
+		mod_timer(&proto->timer, proto->timeout =
+			  jiffies + ppp->req_timeout * HZ);
+	if (action & ZRC)
+		proto->restart_counter = 0;
+	if (action & IRC)
+		proto->restart_counter = (proto->state == STOPPING) ?
+			ppp->term_retries : ppp->cr_retries;
+
+	if (action & SCR)	/* send Configure-Request */
+		ppp_tx_cp(dev, pid, CP_CONF_REQ, proto->cr_id = ++ppp->seq,
+			  0, NULL);
+	if (action & SCA)	/* send Configure-Ack */
+		ppp_tx_cp(dev, pid, CP_CONF_ACK, id, len, data);
+	if (action & SCN)	/* send Configure-Nak/Reject */
+		ppp_tx_cp(dev, pid, code, id, len, data);
+	if (action & STR)	/* send Terminate-Request */
+		ppp_tx_cp(dev, pid, CP_TERM_REQ, ++ppp->seq, 0, NULL);
+	if (action & STA)	/* send Terminate-Ack */
+		ppp_tx_cp(dev, pid, CP_TERM_ACK, id, 0, NULL);
+	if (action & SCJ)	/* send Code-Reject */
+		ppp_tx_cp(dev, pid, CP_CODE_REJ, ++ppp->seq, len, data);
+
+	if (old_state != OPENED && proto->state == OPENED) {
+		netdev_info(dev, "%s up\n", proto_name(pid));
+		if (pid == PID_LCP) {
+			netif_dormant_off(dev);
+			ppp_cp_event(dev, PID_IPCP, START, 0, 0, 0, NULL);
+			ppp_cp_event(dev, PID_IPV6CP, START, 0, 0, 0, NULL);
+			ppp->last_pong = jiffies;
+			mod_timer(&proto->timer, proto->timeout =
+				  jiffies + ppp->keepalive_interval * HZ);
+		}
+	}
+	if (old_state == OPENED && proto->state != OPENED) {
+		netdev_info(dev, "%s down\n", proto_name(pid));
+		if (pid == PID_LCP) {
+			netif_dormant_on(dev);
+			ppp_cp_event(dev, PID_IPCP, STOP, 0, 0, 0, NULL);
+			ppp_cp_event(dev, PID_IPV6CP, STOP, 0, 0, 0, NULL);
+		}
+	}
+	if (old_state != CLOSED && proto->state == CLOSED)
+		del_timer(&proto->timer);
+
+#if DEBUG_STATE
+	printk(KERN_DEBUG "%s: %s ppp_cp_event(%s) ... %s\n", dev->name,
+	       proto_name(pid), event_names[event], state_names[proto->state]);
+#endif
+}
+
+static void ppp_cp_parse_cr(struct net_device *dev, u16 pid, u8 id,
+			    unsigned int req_len, const u8 *data)
+{
+	static u8 const valid_accm[6] = { LCP_OPTION_ACCM, 6, 0, 0, 0, 0 };
+	const u8 *opt;
+	u8 *out;
+	unsigned int len = req_len, nak_len = 0, rej_len = 0;
+
+	out = kmalloc(len, GFP_ATOMIC);
+	if (!out) {
+		dev->stats.rx_dropped++;
+		return;	/* out of memory, ignore CR packet */
+	}
+
+	for (opt = data; len; len -= opt[1], opt += opt[1]) {
+		if (len < 2 || opt[1] < 2 || len < opt[1])
+			goto err_out;
+
+		if (pid == PID_LCP)
+			switch (opt[0]) {
+			case LCP_OPTION_MRU:
+				continue; /* MRU always OK and > 1500 bytes? */
+
+			case LCP_OPTION_ACCM: /* async control character map */
+				if (opt[1] < sizeof(valid_accm))
+					goto err_out;
+				if (!memcmp(opt, valid_accm,
+					    sizeof(valid_accm)))
+					continue;
+				if (!rej_len) { /* NAK it */
+					memcpy(out + nak_len, valid_accm,
+					       sizeof(valid_accm));
+					nak_len += sizeof(valid_accm);
+					continue;
+				}
+				break;
+			case LCP_OPTION_MAGIC:
+				if (len < 6)
+					goto err_out;
+				if (opt[1] != 6 || (!opt[2] && !opt[3] &&
+						    !opt[4] && !opt[5]))
+					break; /* reject invalid magic number */
+				continue;
+			}
+		/* reject this option */
+		memcpy(out + rej_len, opt, opt[1]);
+		rej_len += opt[1];
+	}
+
+	if (rej_len)
+		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_REJ, id, rej_len, out);
+	else if (nak_len)
+		ppp_cp_event(dev, pid, RCR_BAD, CP_CONF_NAK, id, nak_len, out);
+	else
+		ppp_cp_event(dev, pid, RCR_GOOD, CP_CONF_ACK, id, req_len, data);
+
+	kfree(out);
+	return;
+
+err_out:
+	dev->stats.rx_errors++;
+	kfree(out);
+}
+
+static int ppp_rx(struct sk_buff *skb)
+{
+	struct hdlc_header *hdr = (struct hdlc_header *)skb->data;
+	struct net_device *dev = skb->dev;
+	struct ppp *ppp = get_ppp(dev);
+	struct proto *proto;
+	struct cp_header *cp;
+	unsigned long flags;
+	unsigned int len;
+	u16 pid;
+#if DEBUG_CP
+	int i;
+	char *ptr;
+#endif
+
+	spin_lock_irqsave(&ppp->lock, flags);
+	/* Check HDLC header */
+	if (skb->len < sizeof(struct hdlc_header))
+		goto rx_error;
+	cp = skb_pull(skb, sizeof(struct hdlc_header));
+	if (hdr->address != HDLC_ADDR_ALLSTATIONS ||
+	    hdr->control != HDLC_CTRL_UI)
+		goto rx_error;
+
+	pid = ntohs(hdr->protocol);
+	proto = get_proto(dev, pid);
+	if (!proto) {
+		if (ppp->protos[IDX_LCP].state == OPENED)
+			ppp_tx_cp(dev, PID_LCP, LCP_PROTO_REJ,
+				  ++ppp->seq, skb->len + 2, &hdr->protocol);
+		goto rx_error;
+	}
+
+	len = ntohs(cp->len);
+	if (len < sizeof(struct cp_header) /* no complete CP header? */ ||
+	    skb->len < len /* truncated packet? */)
+		goto rx_error;
+	skb_pull(skb, sizeof(struct cp_header));
+	len -= sizeof(struct cp_header);
+
+	/* HDLC and CP headers stripped from skb */
+#if DEBUG_CP
+	if (cp->code < CP_CODES)
+		sprintf(debug_buffer, "[%s id 0x%X]", code_names[cp->code],
+			cp->id);
+	else
+		sprintf(debug_buffer, "[code %u id 0x%X]", cp->code, cp->id);
+	ptr = debug_buffer + strlen(debug_buffer);
+	for (i = 0; i < min_t(unsigned int, len, DEBUG_CP); i++) {
+		sprintf(ptr, " %02X", skb->data[i]);
+		ptr += strlen(ptr);
+	}
+	printk(KERN_DEBUG "%s: RX %s %s\n", dev->name, proto_name(pid),
+	       debug_buffer);
+#endif
+
+	/* LCP only */
+	if (pid == PID_LCP)
+		switch (cp->code) {
+		case LCP_PROTO_REJ:
+			pid = ntohs(*(__be16 *)skb->data);
+			if (pid == PID_LCP || pid == PID_IPCP ||
+			    pid == PID_IPV6CP)
+				ppp_cp_event(dev, pid, RXJ_BAD, 0, 0,
+					     0, NULL);
+			goto out;
+
+		case LCP_ECHO_REQ: /* send Echo-Reply */
+			if (len >= 4 && proto->state == OPENED)
+				ppp_tx_cp(dev, PID_LCP, LCP_ECHO_REPLY,
+					  cp->id, len - 4, skb->data + 4);
+			goto out;
+
+		case LCP_ECHO_REPLY:
+			if (cp->id == ppp->echo_id)
+				ppp->last_pong = jiffies;
+			goto out;
+
+		case LCP_DISC_REQ: /* discard */
+			goto out;
+		}
+
+	/* LCP, IPCP and IPV6CP */
+	switch (cp->code) {
+	case CP_CONF_REQ:
+		ppp_cp_parse_cr(dev, pid, cp->id, len, skb->data);
+		break;
+
+	case CP_CONF_ACK:
+		if (cp->id == proto->cr_id)
+			ppp_cp_event(dev, pid, RCA, 0, 0, 0, NULL);
+		break;
+
+	case CP_CONF_REJ:
+	case CP_CONF_NAK:
+		if (cp->id == proto->cr_id)
+			ppp_cp_event(dev, pid, RCN, 0, 0, 0, NULL);
+		break;
+
+	case CP_TERM_REQ:
+		ppp_cp_event(dev, pid, RTR, 0, cp->id, 0, NULL);
+		break;
+
+	case CP_TERM_ACK:
+		ppp_cp_event(dev, pid, RTA, 0, 0, 0, NULL);
+		break;
+
+	case CP_CODE_REJ:
+		ppp_cp_event(dev, pid, RXJ_BAD, 0, 0, 0, NULL);
+		break;
+
+	default:
+		len += sizeof(struct cp_header);
+		if (len > dev->mtu)
+			len = dev->mtu;
+		ppp_cp_event(dev, pid, RUC, 0, 0, len, cp);
+		break;
+	}
+	goto out;
+
+rx_error:
+	dev->stats.rx_errors++;
+out:
+	spin_unlock_irqrestore(&ppp->lock, flags);
+	dev_kfree_skb_any(skb);
+	ppp_tx_flush();
+	return NET_RX_DROP;
+}
+
+static void ppp_timer(struct timer_list *t)
+{
+	struct proto *proto = from_timer(proto, t, timer);
+	struct ppp *ppp = get_ppp(proto->dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ppp->lock, flags);
+	/* mod_timer could be called after we entered this function but
+	 * before we got the lock.
+	 */
+	if (timer_pending(&proto->timer)) {
+		spin_unlock_irqrestore(&ppp->lock, flags);
+		return;
+	}
+	switch (proto->state) {
+	case STOPPING:
+	case REQ_SENT:
+	case ACK_RECV:
+	case ACK_SENT:
+		if (proto->restart_counter) {
+			ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
+				     0, NULL);
+			proto->restart_counter--;
+		} else if (netif_carrier_ok(proto->dev))
+			ppp_cp_event(proto->dev, proto->pid, TO_GOOD, 0, 0,
+				     0, NULL);
+		else
+			ppp_cp_event(proto->dev, proto->pid, TO_BAD, 0, 0,
+				     0, NULL);
+		break;
+
+	case OPENED:
+		if (proto->pid != PID_LCP)
+			break;
+		if (time_after(jiffies, ppp->last_pong +
+			       ppp->keepalive_timeout * HZ)) {
+			netdev_info(proto->dev, "Link down\n");
+			ppp_cp_event(proto->dev, PID_LCP, STOP, 0, 0, 0, NULL);
+			ppp_cp_event(proto->dev, PID_LCP, START, 0, 0, 0, NULL);
+		} else {	/* send keep-alive packet */
+			ppp->echo_id = ++ppp->seq;
+			ppp_tx_cp(proto->dev, PID_LCP, LCP_ECHO_REQ,
+				  ppp->echo_id, 0, NULL);
+			proto->timer.expires = jiffies +
+				ppp->keepalive_interval * HZ;
+			add_timer(&proto->timer);
+		}
+		break;
+	}
+	spin_unlock_irqrestore(&ppp->lock, flags);
+	ppp_tx_flush();
+}
+
+static void ppp_start(struct net_device *dev)
+{
+	struct ppp *ppp = get_ppp(dev);
+	int i;
+
+	for (i = 0; i < IDX_COUNT; i++) {
+		struct proto *proto = &ppp->protos[i];
+
+		proto->dev = dev;
+		timer_setup(&proto->timer, ppp_timer, 0);
+		proto->state = CLOSED;
+	}
+	ppp->protos[IDX_LCP].pid = PID_LCP;
+	ppp->protos[IDX_IPCP].pid = PID_IPCP;
+	ppp->protos[IDX_IPV6CP].pid = PID_IPV6CP;
+
+	ppp_cp_event(dev, PID_LCP, START, 0, 0, 0, NULL);
+}
+
+static void ppp_stop(struct net_device *dev)
+{
+	ppp_cp_event(dev, PID_LCP, STOP, 0, 0, 0, NULL);
+}
+
+static void ppp_close(struct net_device *dev)
+{
+	ppp_tx_flush();
+}
+
+static struct hdlc_proto proto = {
+	.start		= ppp_start,
+	.stop		= ppp_stop,
+	.close		= ppp_close,
+	.type_trans	= ppp_type_trans,
+	.ioctl		= ppp_ioctl,
+	.netif_rx	= ppp_rx,
+	.module		= THIS_MODULE,
+};
+
+static const struct header_ops ppp_header_ops = {
+	.create = ppp_hard_header,
+};
+
+static int ppp_ioctl(struct net_device *dev, struct if_settings *ifs)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct ppp *ppp;
+	int result;
+
+	switch (ifs->type) {
+	case IF_GET_PROTO:
+		if (dev_to_hdlc(dev)->proto != &proto)
+			return -EINVAL;
+		ifs->type = IF_PROTO_PPP;
+		return 0; /* return protocol only, no settable parameters */
+
+	case IF_PROTO_PPP:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (dev->flags & IFF_UP)
+			return -EBUSY;
+
+		/* no settable parameters */
+
+		result = hdlc->attach(dev, ENCODING_NRZ,
+				      PARITY_CRC16_PR1_CCITT);
+		if (result)
+			return result;
+
+		result = attach_hdlc_protocol(dev, &proto, sizeof(struct ppp));
+		if (result)
+			return result;
+
+		ppp = get_ppp(dev);
+		spin_lock_init(&ppp->lock);
+		ppp->req_timeout = 2;
+		ppp->cr_retries = 10;
+		ppp->term_retries = 2;
+		ppp->keepalive_interval = 10;
+		ppp->keepalive_timeout = 60;
+
+		dev->hard_header_len = sizeof(struct hdlc_header);
+		dev->header_ops = &ppp_header_ops;
+		dev->type = ARPHRD_PPP;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
+		netif_dormant_on(dev);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int __init hdlc_ppp_init(void)
+{
+	skb_queue_head_init(&tx_queue);
+	register_hdlc_protocol(&proto);
+	return 0;
+}
+
+static void __exit hdlc_ppp_exit(void)
+{
+	unregister_hdlc_protocol(&proto);
+}
+
+module_init(hdlc_ppp_init);
+module_exit(hdlc_ppp_exit);
+
+MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
+MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
+MODULE_LICENSE("GPL v2");