https://github.com/torvalds/linux
Tip revision: db98e0b434a6265c451ffe94ec0a29b8d0aaf587 authored by Linus Torvalds on 16 March 2007, 00:20:01 UTC
Linux 2.6.21-rc4
Linux 2.6.21-rc4
Tip revision: db98e0b
syncppp.c
/*
* NET3: A (fairly minimal) implementation of synchronous PPP for Linux
* as well as a CISCO HDLC implementation. See the copyright
* message below for the original source.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the license, or (at your option) any later version.
*
* Note however. This code is also used in a different form by FreeBSD.
* Therefore when making any non OS specific change please consider
* contributing it back to the original author under the terms
* below in addition.
* -- Alan
*
* Port for Linux-2.1 by Jan "Yenya" Kasprzak <kas@fi.muni.cz>
*/
/*
* Synchronous PPP/Cisco link level subroutines.
* Keepalive protocol implemented in both Cisco and PPP modes.
*
* Copyright (C) 1994 Cronyx Ltd.
* Author: Serge Vakulenko, <vak@zebub.msk.su>
*
* This software is distributed with NO WARRANTIES, not even the implied
* warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* Authors grant any other persons or organisations permission to use
* or modify this software as long as this message is kept with the software,
* all derivative works or modified versions.
*
* Version 1.9, Wed Oct 4 18:58:15 MSK 1995
*
* $Id: syncppp.c,v 1.18 2000/04/11 05:25:31 asj Exp $
*/
#undef DEBUG
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/route.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/random.h>
#include <linux/pkt_sched.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <net/syncppp.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#define MAXALIVECNT 6 /* max. alive packets */
#define PPP_ALLSTATIONS 0xff /* All-Stations broadcast address */
#define PPP_UI 0x03 /* Unnumbered Information */
#define PPP_IP 0x0021 /* Internet Protocol */
#define PPP_ISO 0x0023 /* ISO OSI Protocol */
#define PPP_XNS 0x0025 /* Xerox NS Protocol */
#define PPP_IPX 0x002b /* Novell IPX Protocol */
#define PPP_LCP 0xc021 /* Link Control Protocol */
#define PPP_IPCP 0x8021 /* Internet Protocol Control Protocol */
#define LCP_CONF_REQ 1 /* PPP LCP configure request */
#define LCP_CONF_ACK 2 /* PPP LCP configure acknowledge */
#define LCP_CONF_NAK 3 /* PPP LCP configure negative ack */
#define LCP_CONF_REJ 4 /* PPP LCP configure reject */
#define LCP_TERM_REQ 5 /* PPP LCP terminate request */
#define LCP_TERM_ACK 6 /* PPP LCP terminate acknowledge */
#define LCP_CODE_REJ 7 /* PPP LCP code reject */
#define LCP_PROTO_REJ 8 /* PPP LCP protocol reject */
#define LCP_ECHO_REQ 9 /* PPP LCP echo request */
#define LCP_ECHO_REPLY 10 /* PPP LCP echo reply */
#define LCP_DISC_REQ 11 /* PPP LCP discard request */
#define LCP_OPT_MRU 1 /* maximum receive unit */
#define LCP_OPT_ASYNC_MAP 2 /* async control character map */
#define LCP_OPT_AUTH_PROTO 3 /* authentication protocol */
#define LCP_OPT_QUAL_PROTO 4 /* quality protocol */
#define LCP_OPT_MAGIC 5 /* magic number */
#define LCP_OPT_RESERVED 6 /* reserved */
#define LCP_OPT_PROTO_COMP 7 /* protocol field compression */
#define LCP_OPT_ADDR_COMP 8 /* address/control field compression */
#define IPCP_CONF_REQ LCP_CONF_REQ /* PPP IPCP configure request */
#define IPCP_CONF_ACK LCP_CONF_ACK /* PPP IPCP configure acknowledge */
#define IPCP_CONF_NAK LCP_CONF_NAK /* PPP IPCP configure negative ack */
#define IPCP_CONF_REJ LCP_CONF_REJ /* PPP IPCP configure reject */
#define IPCP_TERM_REQ LCP_TERM_REQ /* PPP IPCP terminate request */
#define IPCP_TERM_ACK LCP_TERM_ACK /* PPP IPCP terminate acknowledge */
#define IPCP_CODE_REJ LCP_CODE_REJ /* PPP IPCP code reject */
#define CISCO_MULTICAST 0x8f /* Cisco multicast address */
#define CISCO_UNICAST 0x0f /* Cisco unicast address */
#define CISCO_KEEPALIVE 0x8035 /* Cisco keepalive protocol */
#define CISCO_ADDR_REQ 0 /* Cisco address request */
#define CISCO_ADDR_REPLY 1 /* Cisco address reply */
#define CISCO_KEEPALIVE_REQ 2 /* Cisco keepalive request */
struct ppp_header {
u8 address;
u8 control;
u16 protocol;
};
#define PPP_HEADER_LEN sizeof (struct ppp_header)
struct lcp_header {
u8 type;
u8 ident;
u16 len;
};
#define LCP_HEADER_LEN sizeof (struct lcp_header)
struct cisco_packet {
u32 type;
u32 par1;
u32 par2;
u16 rel;
u16 time0;
u16 time1;
};
#define CISCO_PACKET_LEN 18
#define CISCO_BIG_PACKET_LEN 20
static struct sppp *spppq;
static struct timer_list sppp_keepalive_timer;
static DEFINE_SPINLOCK(spppq_lock);
/* global xmit queue for sending packets while spinlock is held */
static struct sk_buff_head tx_queue;
static void sppp_keepalive (unsigned long dummy);
static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
u8 ident, u16 len, void *data);
static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2);
static void sppp_lcp_input (struct sppp *sp, struct sk_buff *m);
static void sppp_cisco_input (struct sppp *sp, struct sk_buff *m);
static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *m);
static void sppp_lcp_open (struct sppp *sp);
static void sppp_ipcp_open (struct sppp *sp);
static int sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
int len, u32 *magic);
static void sppp_cp_timeout (unsigned long arg);
static char *sppp_lcp_type_name (u8 type);
static char *sppp_ipcp_type_name (u8 type);
static void sppp_print_bytes (u8 *p, u16 len);
static int debug;
/* Flush global outgoing packet queue to dev_queue_xmit().
*
* dev_queue_xmit() must be called with interrupts enabled
* which means it can't be called with spinlocks held.
* If a packet needs to be sent while a spinlock is held,
* then put the packet into tx_queue, and call sppp_flush_xmit()
* after spinlock is released.
*/
static void sppp_flush_xmit(void)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&tx_queue)) != NULL)
dev_queue_xmit(skb);
}
/*
* Interface down stub
*/
static void if_down(struct net_device *dev)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
sp->pp_link_state=SPPP_LINK_DOWN;
}
/*
* Timeout routine activations.
*/
static void sppp_set_timeout(struct sppp *p,int s)
{
if (! (p->pp_flags & PP_TIMO))
{
init_timer(&p->pp_timer);
p->pp_timer.function=sppp_cp_timeout;
p->pp_timer.expires=jiffies+s*HZ;
p->pp_timer.data=(unsigned long)p;
p->pp_flags |= PP_TIMO;
add_timer(&p->pp_timer);
}
}
static void sppp_clear_timeout(struct sppp *p)
{
if (p->pp_flags & PP_TIMO)
{
del_timer(&p->pp_timer);
p->pp_flags &= ~PP_TIMO;
}
}
/**
* sppp_input - receive and process a WAN PPP frame
* @skb: The buffer to process
* @dev: The device it arrived on
*
* This can be called directly by cards that do not have
* timing constraints but is normally called from the network layer
* after interrupt servicing to process frames queued via netif_rx().
*
* We process the options in the card. If the frame is destined for
* the protocol stacks then it requeues the frame for the upper level
* protocol. If it is a control from it is processed and discarded
* here.
*/
static void sppp_input (struct net_device *dev, struct sk_buff *skb)
{
struct ppp_header *h;
struct sppp *sp = (struct sppp *)sppp_of(dev);
unsigned long flags;
skb->dev=dev;
skb->mac.raw=skb->data;
if (dev->flags & IFF_RUNNING)
{
/* Count received bytes, add FCS and one flag */
sp->ibytes+= skb->len + 3;
sp->ipkts++;
}
if (!pskb_may_pull(skb, PPP_HEADER_LEN)) {
/* Too small packet, drop it. */
if (sp->pp_flags & PP_DEBUG)
printk (KERN_DEBUG "%s: input packet is too small, %d bytes\n",
dev->name, skb->len);
kfree_skb(skb);
return;
}
/* Get PPP header. */
h = (struct ppp_header *)skb->data;
skb_pull(skb,sizeof(struct ppp_header));
spin_lock_irqsave(&sp->lock, flags);
switch (h->address) {
default: /* Invalid PPP packet. */
goto invalid;
case PPP_ALLSTATIONS:
if (h->control != PPP_UI)
goto invalid;
if (sp->pp_flags & PP_CISCO) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: PPP packet in Cisco mode <0x%x 0x%x 0x%x>\n",
dev->name,
h->address, h->control, ntohs (h->protocol));
goto drop;
}
switch (ntohs (h->protocol)) {
default:
if (sp->lcp.state == LCP_STATE_OPENED)
sppp_cp_send (sp, PPP_LCP, LCP_PROTO_REJ,
++sp->pp_seq, skb->len + 2,
&h->protocol);
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid input protocol <0x%x 0x%x 0x%x>\n",
dev->name,
h->address, h->control, ntohs (h->protocol));
goto drop;
case PPP_LCP:
sppp_lcp_input (sp, skb);
goto drop;
case PPP_IPCP:
if (sp->lcp.state == LCP_STATE_OPENED)
sppp_ipcp_input (sp, skb);
else
printk(KERN_DEBUG "IPCP when still waiting LCP finish.\n");
goto drop;
case PPP_IP:
if (sp->ipcp.state == IPCP_STATE_OPENED) {
if(sp->pp_flags&PP_DEBUG)
printk(KERN_DEBUG "Yow an IP frame.\n");
skb->protocol=htons(ETH_P_IP);
netif_rx(skb);
dev->last_rx = jiffies;
goto done;
}
break;
#ifdef IPX
case PPP_IPX:
/* IPX IPXCP not implemented yet */
if (sp->lcp.state == LCP_STATE_OPENED) {
skb->protocol=htons(ETH_P_IPX);
netif_rx(skb);
dev->last_rx = jiffies;
goto done;
}
break;
#endif
}
break;
case CISCO_MULTICAST:
case CISCO_UNICAST:
/* Don't check the control field here (RFC 1547). */
if (! (sp->pp_flags & PP_CISCO)) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: Cisco packet in PPP mode <0x%x 0x%x 0x%x>\n",
dev->name,
h->address, h->control, ntohs (h->protocol));
goto drop;
}
switch (ntohs (h->protocol)) {
default:
goto invalid;
case CISCO_KEEPALIVE:
sppp_cisco_input (sp, skb);
goto drop;
#ifdef CONFIG_INET
case ETH_P_IP:
skb->protocol=htons(ETH_P_IP);
netif_rx(skb);
dev->last_rx = jiffies;
goto done;
#endif
#ifdef CONFIG_IPX
case ETH_P_IPX:
skb->protocol=htons(ETH_P_IPX);
netif_rx(skb);
dev->last_rx = jiffies;
goto done;
#endif
}
break;
}
goto drop;
invalid:
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid input packet <0x%x 0x%x 0x%x>\n",
dev->name, h->address, h->control, ntohs (h->protocol));
drop:
kfree_skb(skb);
done:
spin_unlock_irqrestore(&sp->lock, flags);
sppp_flush_xmit();
return;
}
/*
* Handle transmit packets.
*/
static int sppp_hard_header(struct sk_buff *skb, struct net_device *dev, __u16 type,
void *daddr, void *saddr, unsigned int len)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
struct ppp_header *h;
skb_push(skb,sizeof(struct ppp_header));
h=(struct ppp_header *)skb->data;
if(sp->pp_flags&PP_CISCO)
{
h->address = CISCO_UNICAST;
h->control = 0;
}
else
{
h->address = PPP_ALLSTATIONS;
h->control = PPP_UI;
}
if(sp->pp_flags & PP_CISCO)
{
h->protocol = htons(type);
}
else switch(type)
{
case ETH_P_IP:
h->protocol = htons(PPP_IP);
break;
case ETH_P_IPX:
h->protocol = htons(PPP_IPX);
break;
}
return sizeof(struct ppp_header);
}
static int sppp_rebuild_header(struct sk_buff *skb)
{
return 0;
}
/*
* Send keepalive packets, every 10 seconds.
*/
static void sppp_keepalive (unsigned long dummy)
{
struct sppp *sp;
unsigned long flags;
spin_lock_irqsave(&spppq_lock, flags);
for (sp=spppq; sp; sp=sp->pp_next)
{
struct net_device *dev = sp->pp_if;
/* Keepalive mode disabled or channel down? */
if (! (sp->pp_flags & PP_KEEPALIVE) ||
! (dev->flags & IFF_UP))
continue;
spin_lock(&sp->lock);
/* No keepalive in PPP mode if LCP not opened yet. */
if (! (sp->pp_flags & PP_CISCO) &&
sp->lcp.state != LCP_STATE_OPENED) {
spin_unlock(&sp->lock);
continue;
}
if (sp->pp_alivecnt == MAXALIVECNT) {
/* No keepalive packets got. Stop the interface. */
printk (KERN_WARNING "%s: protocol down\n", dev->name);
if_down (dev);
if (! (sp->pp_flags & PP_CISCO)) {
/* Shut down the PPP link. */
sp->lcp.magic = jiffies;
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
sppp_clear_timeout (sp);
/* Initiate negotiation. */
sppp_lcp_open (sp);
}
}
if (sp->pp_alivecnt <= MAXALIVECNT)
++sp->pp_alivecnt;
if (sp->pp_flags & PP_CISCO)
sppp_cisco_send (sp, CISCO_KEEPALIVE_REQ, ++sp->pp_seq,
sp->pp_rseq);
else if (sp->lcp.state == LCP_STATE_OPENED) {
long nmagic = htonl (sp->lcp.magic);
sp->lcp.echoid = ++sp->pp_seq;
sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REQ,
sp->lcp.echoid, 4, &nmagic);
}
spin_unlock(&sp->lock);
}
spin_unlock_irqrestore(&spppq_lock, flags);
sppp_flush_xmit();
sppp_keepalive_timer.expires=jiffies+10*HZ;
add_timer(&sppp_keepalive_timer);
}
/*
* Handle incoming PPP Link Control Protocol packets.
*/
static void sppp_lcp_input (struct sppp *sp, struct sk_buff *skb)
{
struct lcp_header *h;
struct net_device *dev = sp->pp_if;
int len = skb->len;
u8 *p, opt[6];
u32 rmagic = 0;
if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid lcp packet length: %d bytes\n",
dev->name, len);
return;
}
h = (struct lcp_header *)skb->data;
skb_pull(skb,sizeof(struct lcp_header *));
if (sp->pp_flags & PP_DEBUG)
{
char state = '?';
switch (sp->lcp.state) {
case LCP_STATE_CLOSED: state = 'C'; break;
case LCP_STATE_ACK_RCVD: state = 'R'; break;
case LCP_STATE_ACK_SENT: state = 'S'; break;
case LCP_STATE_OPENED: state = 'O'; break;
}
printk (KERN_WARNING "%s: lcp input(%c): %d bytes <%s id=%xh len=%xh",
dev->name, state, len,
sppp_lcp_type_name (h->type), h->ident, ntohs (h->len));
if (len > 4)
sppp_print_bytes ((u8*) (h+1), len-4);
printk (">\n");
}
if (len > ntohs (h->len))
len = ntohs (h->len);
switch (h->type) {
default:
/* Unknown packet type -- send Code-Reject packet. */
sppp_cp_send (sp, PPP_LCP, LCP_CODE_REJ, ++sp->pp_seq,
skb->len, h);
break;
case LCP_CONF_REQ:
if (len < 4) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_DEBUG"%s: invalid lcp configure request packet length: %d bytes\n",
dev->name, len);
break;
}
if (len>4 && !sppp_lcp_conf_parse_options (sp, h, len, &rmagic))
goto badreq;
if (rmagic == sp->lcp.magic) {
/* Local and remote magics equal -- loopback? */
if (sp->pp_loopcnt >= MAXALIVECNT*5) {
printk (KERN_WARNING "%s: loopback\n",
dev->name);
sp->pp_loopcnt = 0;
if (dev->flags & IFF_UP) {
if_down (dev);
}
} else if (sp->pp_flags & PP_DEBUG)
printk (KERN_DEBUG "%s: conf req: magic glitch\n",
dev->name);
++sp->pp_loopcnt;
/* MUST send Conf-Nack packet. */
rmagic = ~sp->lcp.magic;
opt[0] = LCP_OPT_MAGIC;
opt[1] = sizeof (opt);
opt[2] = rmagic >> 24;
opt[3] = rmagic >> 16;
opt[4] = rmagic >> 8;
opt[5] = rmagic;
sppp_cp_send (sp, PPP_LCP, LCP_CONF_NAK,
h->ident, sizeof (opt), &opt);
badreq:
switch (sp->lcp.state) {
case LCP_STATE_OPENED:
/* Initiate renegotiation. */
sppp_lcp_open (sp);
/* fall through... */
case LCP_STATE_ACK_SENT:
/* Go to closed state. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
}
break;
}
/* Send Configure-Ack packet. */
sp->pp_loopcnt = 0;
if (sp->lcp.state != LCP_STATE_OPENED) {
sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
h->ident, len-4, h+1);
}
/* Change the state. */
switch (sp->lcp.state) {
case LCP_STATE_CLOSED:
sp->lcp.state = LCP_STATE_ACK_SENT;
break;
case LCP_STATE_ACK_RCVD:
sp->lcp.state = LCP_STATE_OPENED;
sppp_ipcp_open (sp);
break;
case LCP_STATE_OPENED:
/* Remote magic changed -- close session. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
/* Initiate renegotiation. */
sppp_lcp_open (sp);
/* Send ACK after our REQ in attempt to break loop */
sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
h->ident, len-4, h+1);
sp->lcp.state = LCP_STATE_ACK_SENT;
break;
}
break;
case LCP_CONF_ACK:
if (h->ident != sp->lcp.confid)
break;
sppp_clear_timeout (sp);
if ((sp->pp_link_state != SPPP_LINK_UP) &&
(dev->flags & IFF_UP)) {
/* Coming out of loopback mode. */
sp->pp_link_state=SPPP_LINK_UP;
printk (KERN_INFO "%s: protocol up\n", dev->name);
}
switch (sp->lcp.state) {
case LCP_STATE_CLOSED:
sp->lcp.state = LCP_STATE_ACK_RCVD;
sppp_set_timeout (sp, 5);
break;
case LCP_STATE_ACK_SENT:
sp->lcp.state = LCP_STATE_OPENED;
sppp_ipcp_open (sp);
break;
}
break;
case LCP_CONF_NAK:
if (h->ident != sp->lcp.confid)
break;
p = (u8*) (h+1);
if (len>=10 && p[0] == LCP_OPT_MAGIC && p[1] >= 4) {
rmagic = (u32)p[2] << 24 |
(u32)p[3] << 16 | p[4] << 8 | p[5];
if (rmagic == ~sp->lcp.magic) {
int newmagic;
if (sp->pp_flags & PP_DEBUG)
printk (KERN_DEBUG "%s: conf nak: magic glitch\n",
dev->name);
get_random_bytes(&newmagic, sizeof(newmagic));
sp->lcp.magic += newmagic;
} else
sp->lcp.magic = rmagic;
}
if (sp->lcp.state != LCP_STATE_ACK_SENT) {
/* Go to closed state. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
}
/* The link will be renegotiated after timeout,
* to avoid endless req-nack loop. */
sppp_clear_timeout (sp);
sppp_set_timeout (sp, 2);
break;
case LCP_CONF_REJ:
if (h->ident != sp->lcp.confid)
break;
sppp_clear_timeout (sp);
/* Initiate renegotiation. */
sppp_lcp_open (sp);
if (sp->lcp.state != LCP_STATE_ACK_SENT) {
/* Go to closed state. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
}
break;
case LCP_TERM_REQ:
sppp_clear_timeout (sp);
/* Send Terminate-Ack packet. */
sppp_cp_send (sp, PPP_LCP, LCP_TERM_ACK, h->ident, 0, NULL);
/* Go to closed state. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
/* Initiate renegotiation. */
sppp_lcp_open (sp);
break;
case LCP_TERM_ACK:
case LCP_CODE_REJ:
case LCP_PROTO_REJ:
/* Ignore for now. */
break;
case LCP_DISC_REQ:
/* Discard the packet. */
break;
case LCP_ECHO_REQ:
if (sp->lcp.state != LCP_STATE_OPENED)
break;
if (len < 8) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid lcp echo request packet length: %d bytes\n",
dev->name, len);
break;
}
if (ntohl (*(long*)(h+1)) == sp->lcp.magic) {
/* Line loopback mode detected. */
printk (KERN_WARNING "%s: loopback\n", dev->name);
if_down (dev);
/* Shut down the PPP link. */
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
sppp_clear_timeout (sp);
/* Initiate negotiation. */
sppp_lcp_open (sp);
break;
}
*(long*)(h+1) = htonl (sp->lcp.magic);
sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REPLY, h->ident, len-4, h+1);
break;
case LCP_ECHO_REPLY:
if (h->ident != sp->lcp.echoid)
break;
if (len < 8) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid lcp echo reply packet length: %d bytes\n",
dev->name, len);
break;
}
if (ntohl (*(long*)(h+1)) != sp->lcp.magic)
sp->pp_alivecnt = 0;
break;
}
}
/*
* Handle incoming Cisco keepalive protocol packets.
*/
static void sppp_cisco_input (struct sppp *sp, struct sk_buff *skb)
{
struct cisco_packet *h;
struct net_device *dev = sp->pp_if;
if (!pskb_may_pull(skb, sizeof(struct cisco_packet))
|| (skb->len != CISCO_PACKET_LEN
&& skb->len != CISCO_BIG_PACKET_LEN)) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid cisco packet length: %d bytes\n",
dev->name, skb->len);
return;
}
h = (struct cisco_packet *)skb->data;
skb_pull(skb, sizeof(struct cisco_packet*));
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: cisco input: %d bytes <%xh %xh %xh %xh %xh-%xh>\n",
dev->name, skb->len,
ntohl (h->type), h->par1, h->par2, h->rel,
h->time0, h->time1);
switch (ntohl (h->type)) {
default:
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: unknown cisco packet type: 0x%x\n",
dev->name, ntohl (h->type));
break;
case CISCO_ADDR_REPLY:
/* Reply on address request, ignore */
break;
case CISCO_KEEPALIVE_REQ:
sp->pp_alivecnt = 0;
sp->pp_rseq = ntohl (h->par1);
if (sp->pp_seq == sp->pp_rseq) {
/* Local and remote sequence numbers are equal.
* Probably, the line is in loopback mode. */
int newseq;
if (sp->pp_loopcnt >= MAXALIVECNT) {
printk (KERN_WARNING "%s: loopback\n",
dev->name);
sp->pp_loopcnt = 0;
if (dev->flags & IFF_UP) {
if_down (dev);
}
}
++sp->pp_loopcnt;
/* Generate new local sequence number */
get_random_bytes(&newseq, sizeof(newseq));
sp->pp_seq ^= newseq;
break;
}
sp->pp_loopcnt = 0;
if (sp->pp_link_state==SPPP_LINK_DOWN &&
(dev->flags & IFF_UP)) {
sp->pp_link_state=SPPP_LINK_UP;
printk (KERN_INFO "%s: protocol up\n", dev->name);
}
break;
case CISCO_ADDR_REQ:
/* Stolen from net/ipv4/devinet.c -- SIOCGIFADDR ioctl */
{
struct in_device *in_dev;
struct in_ifaddr *ifa;
__be32 addr = 0, mask = ~0; /* FIXME: is the mask correct? */
#ifdef CONFIG_INET
rcu_read_lock();
if ((in_dev = __in_dev_get_rcu(dev)) != NULL)
{
for (ifa=in_dev->ifa_list; ifa != NULL;
ifa=ifa->ifa_next) {
if (strcmp(dev->name, ifa->ifa_label) == 0)
{
addr = ifa->ifa_local;
mask = ifa->ifa_mask;
break;
}
}
}
rcu_read_unlock();
#endif
/* I hope both addr and mask are in the net order */
sppp_cisco_send (sp, CISCO_ADDR_REPLY, addr, mask);
break;
}
}
}
/*
* Send PPP LCP packet.
*/
static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
u8 ident, u16 len, void *data)
{
struct ppp_header *h;
struct lcp_header *lh;
struct sk_buff *skb;
struct net_device *dev = sp->pp_if;
skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+LCP_HEADER_LEN+len,
GFP_ATOMIC);
if (skb==NULL)
return;
skb_reserve(skb,dev->hard_header_len);
h = (struct ppp_header *)skb_put(skb, sizeof(struct ppp_header));
h->address = PPP_ALLSTATIONS; /* broadcast address */
h->control = PPP_UI; /* Unnumbered Info */
h->protocol = htons (proto); /* Link Control Protocol */
lh = (struct lcp_header *)skb_put(skb, sizeof(struct lcp_header));
lh->type = type;
lh->ident = ident;
lh->len = htons (LCP_HEADER_LEN + len);
if (len)
memcpy(skb_put(skb,len),data, len);
if (sp->pp_flags & PP_DEBUG) {
printk (KERN_WARNING "%s: %s output <%s id=%xh len=%xh",
dev->name,
proto==PPP_LCP ? "lcp" : "ipcp",
proto==PPP_LCP ? sppp_lcp_type_name (lh->type) :
sppp_ipcp_type_name (lh->type), lh->ident,
ntohs (lh->len));
if (len)
sppp_print_bytes ((u8*) (lh+1), len);
printk (">\n");
}
sp->obytes += skb->len;
/* Control is high priority so it doesn't get queued behind data */
skb->priority=TC_PRIO_CONTROL;
skb->dev = dev;
skb_queue_tail(&tx_queue, skb);
}
/*
* Send Cisco keepalive packet.
*/
static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2)
{
struct ppp_header *h;
struct cisco_packet *ch;
struct sk_buff *skb;
struct net_device *dev = sp->pp_if;
u32 t = jiffies * 1000/HZ;
skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+CISCO_PACKET_LEN,
GFP_ATOMIC);
if(skb==NULL)
return;
skb_reserve(skb, dev->hard_header_len);
h = (struct ppp_header *)skb_put (skb, sizeof(struct ppp_header));
h->address = CISCO_MULTICAST;
h->control = 0;
h->protocol = htons (CISCO_KEEPALIVE);
ch = (struct cisco_packet*)skb_put(skb, CISCO_PACKET_LEN);
ch->type = htonl (type);
ch->par1 = htonl (par1);
ch->par2 = htonl (par2);
ch->rel = -1;
ch->time0 = htons ((u16) (t >> 16));
ch->time1 = htons ((u16) t);
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: cisco output: <%xh %xh %xh %xh %xh-%xh>\n",
dev->name, ntohl (ch->type), ch->par1,
ch->par2, ch->rel, ch->time0, ch->time1);
sp->obytes += skb->len;
skb->priority=TC_PRIO_CONTROL;
skb->dev = dev;
skb_queue_tail(&tx_queue, skb);
}
/**
* sppp_close - close down a synchronous PPP or Cisco HDLC link
* @dev: The network device to drop the link of
*
* This drops the logical interface to the channel. It is not
* done politely as we assume we will also be dropping DTR. Any
* timeouts are killed.
*/
int sppp_close (struct net_device *dev)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
unsigned long flags;
spin_lock_irqsave(&sp->lock, flags);
sp->pp_link_state = SPPP_LINK_DOWN;
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
sppp_clear_timeout (sp);
spin_unlock_irqrestore(&sp->lock, flags);
return 0;
}
EXPORT_SYMBOL(sppp_close);
/**
* sppp_open - open a synchronous PPP or Cisco HDLC link
* @dev: Network device to activate
*
* Close down any existing synchronous session and commence
* from scratch. In the PPP case this means negotiating LCP/IPCP
* and friends, while for Cisco HDLC we simply need to start sending
* keepalives
*/
int sppp_open (struct net_device *dev)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
unsigned long flags;
sppp_close(dev);
spin_lock_irqsave(&sp->lock, flags);
if (!(sp->pp_flags & PP_CISCO)) {
sppp_lcp_open (sp);
}
sp->pp_link_state = SPPP_LINK_DOWN;
spin_unlock_irqrestore(&sp->lock, flags);
sppp_flush_xmit();
return 0;
}
EXPORT_SYMBOL(sppp_open);
/**
* sppp_reopen - notify of physical link loss
* @dev: Device that lost the link
*
* This function informs the synchronous protocol code that
* the underlying link died (for example a carrier drop on X.21)
*
* We increment the magic numbers to ensure that if the other end
* failed to notice we will correctly start a new session. It happens
* do to the nature of telco circuits is that you can lose carrier on
* one endonly.
*
* Having done this we go back to negotiating. This function may
* be called from an interrupt context.
*/
int sppp_reopen (struct net_device *dev)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
unsigned long flags;
sppp_close(dev);
spin_lock_irqsave(&sp->lock, flags);
if (!(sp->pp_flags & PP_CISCO))
{
sp->lcp.magic = jiffies;
++sp->pp_seq;
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
/* Give it a moment for the line to settle then go */
sppp_set_timeout (sp, 1);
}
sp->pp_link_state=SPPP_LINK_DOWN;
spin_unlock_irqrestore(&sp->lock, flags);
return 0;
}
EXPORT_SYMBOL(sppp_reopen);
/**
* sppp_change_mtu - Change the link MTU
* @dev: Device to change MTU on
* @new_mtu: New MTU
*
* Change the MTU on the link. This can only be called with
* the link down. It returns an error if the link is up or
* the mtu is out of range.
*/
static int sppp_change_mtu(struct net_device *dev, int new_mtu)
{
if(new_mtu<128||new_mtu>PPP_MTU||(dev->flags&IFF_UP))
return -EINVAL;
dev->mtu=new_mtu;
return 0;
}
/**
* sppp_do_ioctl - Ioctl handler for ppp/hdlc
* @dev: Device subject to ioctl
* @ifr: Interface request block from the user
* @cmd: Command that is being issued
*
* This function handles the ioctls that may be issued by the user
* to control the settings of a PPP/HDLC link. It does both busy
* and security checks. This function is intended to be wrapped by
* callers who wish to add additional ioctl calls of their own.
*/
int sppp_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
struct sppp *sp = (struct sppp *)sppp_of(dev);
if(dev->flags&IFF_UP)
return -EBUSY;
if(!capable(CAP_NET_ADMIN))
return -EPERM;
switch(cmd)
{
case SPPPIOCCISCO:
sp->pp_flags|=PP_CISCO;
dev->type = ARPHRD_HDLC;
break;
case SPPPIOCPPP:
sp->pp_flags&=~PP_CISCO;
dev->type = ARPHRD_PPP;
break;
case SPPPIOCDEBUG:
sp->pp_flags&=~PP_DEBUG;
if(ifr->ifr_flags)
sp->pp_flags|=PP_DEBUG;
break;
case SPPPIOCGFLAGS:
if(copy_to_user(ifr->ifr_data, &sp->pp_flags, sizeof(sp->pp_flags)))
return -EFAULT;
break;
case SPPPIOCSFLAGS:
if(copy_from_user(&sp->pp_flags, ifr->ifr_data, sizeof(sp->pp_flags)))
return -EFAULT;
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL(sppp_do_ioctl);
/**
* sppp_attach - attach synchronous PPP/HDLC to a device
* @pd: PPP device to initialise
*
* This initialises the PPP/HDLC support on an interface. At the
* time of calling the dev element must point to the network device
* that this interface is attached to. The interface should not yet
* be registered.
*/
void sppp_attach(struct ppp_device *pd)
{
struct net_device *dev = pd->dev;
struct sppp *sp = &pd->sppp;
unsigned long flags;
/* Make sure embedding is safe for sppp_of */
BUG_ON(sppp_of(dev) != sp);
spin_lock_irqsave(&spppq_lock, flags);
/* Initialize keepalive handler. */
if (! spppq)
{
init_timer(&sppp_keepalive_timer);
sppp_keepalive_timer.expires=jiffies+10*HZ;
sppp_keepalive_timer.function=sppp_keepalive;
add_timer(&sppp_keepalive_timer);
}
/* Insert new entry into the keepalive list. */
sp->pp_next = spppq;
spppq = sp;
spin_unlock_irqrestore(&spppq_lock, flags);
sp->pp_loopcnt = 0;
sp->pp_alivecnt = 0;
sp->pp_seq = 0;
sp->pp_rseq = 0;
sp->pp_flags = PP_KEEPALIVE|PP_CISCO|debug;/*PP_DEBUG;*/
sp->lcp.magic = 0;
sp->lcp.state = LCP_STATE_CLOSED;
sp->ipcp.state = IPCP_STATE_CLOSED;
sp->pp_if = dev;
spin_lock_init(&sp->lock);
/*
* Device specific setup. All but interrupt handler and
* hard_start_xmit.
*/
dev->hard_header = sppp_hard_header;
dev->rebuild_header = sppp_rebuild_header;
dev->tx_queue_len = 10;
dev->type = ARPHRD_HDLC;
dev->addr_len = 0;
dev->hard_header_len = sizeof(struct ppp_header);
dev->mtu = PPP_MTU;
/*
* These 4 are callers but MUST also call sppp_ functions
*/
dev->do_ioctl = sppp_do_ioctl;
#if 0
dev->get_stats = NULL; /* Let the driver override these */
dev->open = sppp_open;
dev->stop = sppp_close;
#endif
dev->change_mtu = sppp_change_mtu;
dev->hard_header_cache = NULL;
dev->header_cache_update = NULL;
dev->flags = IFF_MULTICAST|IFF_POINTOPOINT|IFF_NOARP;
}
EXPORT_SYMBOL(sppp_attach);
/**
* sppp_detach - release PPP resources from a device
* @dev: Network device to release
*
* Stop and free up any PPP/HDLC resources used by this
* interface. This must be called before the device is
* freed.
*/
void sppp_detach (struct net_device *dev)
{
struct sppp **q, *p, *sp = (struct sppp *)sppp_of(dev);
unsigned long flags;
spin_lock_irqsave(&spppq_lock, flags);
/* Remove the entry from the keepalive list. */
for (q = &spppq; (p = *q); q = &p->pp_next)
if (p == sp) {
*q = p->pp_next;
break;
}
/* Stop keepalive handler. */
if (! spppq)
del_timer(&sppp_keepalive_timer);
sppp_clear_timeout (sp);
spin_unlock_irqrestore(&spppq_lock, flags);
}
EXPORT_SYMBOL(sppp_detach);
/*
* Analyze the LCP Configure-Request options list
* for the presence of unknown options.
* If the request contains unknown options, build and
* send Configure-reject packet, containing only unknown options.
*/
static int
sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
int len, u32 *magic)
{
u8 *buf, *r, *p;
int rlen;
len -= 4;
buf = r = kmalloc (len, GFP_ATOMIC);
if (! buf)
return (0);
p = (void*) (h+1);
for (rlen=0; len>1 && p[1]; len-=p[1], p+=p[1]) {
switch (*p) {
case LCP_OPT_MAGIC:
/* Magic number -- extract. */
if (len >= 6 && p[1] == 6) {
*magic = (u32)p[2] << 24 |
(u32)p[3] << 16 | p[4] << 8 | p[5];
continue;
}
break;
case LCP_OPT_ASYNC_MAP:
/* Async control character map -- check to be zero. */
if (len >= 6 && p[1] == 6 && ! p[2] && ! p[3] &&
! p[4] && ! p[5])
continue;
break;
case LCP_OPT_MRU:
/* Maximum receive unit -- always OK. */
continue;
default:
/* Others not supported. */
break;
}
/* Add the option to rejected list. */
memcpy(r, p, p[1]);
r += p[1];
rlen += p[1];
}
if (rlen)
sppp_cp_send (sp, PPP_LCP, LCP_CONF_REJ, h->ident, rlen, buf);
kfree(buf);
return (rlen == 0);
}
static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *skb)
{
struct lcp_header *h;
struct net_device *dev = sp->pp_if;
int len = skb->len;
if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid ipcp packet length: %d bytes\n",
dev->name, len);
return;
}
h = (struct lcp_header *)skb->data;
skb_pull(skb,sizeof(struct lcp_header));
if (sp->pp_flags & PP_DEBUG) {
printk (KERN_WARNING "%s: ipcp input: %d bytes <%s id=%xh len=%xh",
dev->name, len,
sppp_ipcp_type_name (h->type), h->ident, ntohs (h->len));
if (len > 4)
sppp_print_bytes ((u8*) (h+1), len-4);
printk (">\n");
}
if (len > ntohs (h->len))
len = ntohs (h->len);
switch (h->type) {
default:
/* Unknown packet type -- send Code-Reject packet. */
sppp_cp_send (sp, PPP_IPCP, IPCP_CODE_REJ, ++sp->pp_seq, len, h);
break;
case IPCP_CONF_REQ:
if (len < 4) {
if (sp->pp_flags & PP_DEBUG)
printk (KERN_WARNING "%s: invalid ipcp configure request packet length: %d bytes\n",
dev->name, len);
return;
}
if (len > 4) {
sppp_cp_send (sp, PPP_IPCP, LCP_CONF_REJ, h->ident,
len-4, h+1);
switch (sp->ipcp.state) {
case IPCP_STATE_OPENED:
/* Initiate renegotiation. */
sppp_ipcp_open (sp);
/* fall through... */
case IPCP_STATE_ACK_SENT:
/* Go to closed state. */
sp->ipcp.state = IPCP_STATE_CLOSED;
}
} else {
/* Send Configure-Ack packet. */
sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_ACK, h->ident,
0, NULL);
/* Change the state. */
if (sp->ipcp.state == IPCP_STATE_ACK_RCVD)
sp->ipcp.state = IPCP_STATE_OPENED;
else
sp->ipcp.state = IPCP_STATE_ACK_SENT;
}
break;
case IPCP_CONF_ACK:
if (h->ident != sp->ipcp.confid)
break;
sppp_clear_timeout (sp);
switch (sp->ipcp.state) {
case IPCP_STATE_CLOSED:
sp->ipcp.state = IPCP_STATE_ACK_RCVD;
sppp_set_timeout (sp, 5);
break;
case IPCP_STATE_ACK_SENT:
sp->ipcp.state = IPCP_STATE_OPENED;
break;
}
break;
case IPCP_CONF_NAK:
case IPCP_CONF_REJ:
if (h->ident != sp->ipcp.confid)
break;
sppp_clear_timeout (sp);
/* Initiate renegotiation. */
sppp_ipcp_open (sp);
if (sp->ipcp.state != IPCP_STATE_ACK_SENT)
/* Go to closed state. */
sp->ipcp.state = IPCP_STATE_CLOSED;
break;
case IPCP_TERM_REQ:
/* Send Terminate-Ack packet. */
sppp_cp_send (sp, PPP_IPCP, IPCP_TERM_ACK, h->ident, 0, NULL);
/* Go to closed state. */
sp->ipcp.state = IPCP_STATE_CLOSED;
/* Initiate renegotiation. */
sppp_ipcp_open (sp);
break;
case IPCP_TERM_ACK:
/* Ignore for now. */
case IPCP_CODE_REJ:
/* Ignore for now. */
break;
}
}
static void sppp_lcp_open (struct sppp *sp)
{
char opt[6];
if (! sp->lcp.magic)
sp->lcp.magic = jiffies;
opt[0] = LCP_OPT_MAGIC;
opt[1] = sizeof (opt);
opt[2] = sp->lcp.magic >> 24;
opt[3] = sp->lcp.magic >> 16;
opt[4] = sp->lcp.magic >> 8;
opt[5] = sp->lcp.magic;
sp->lcp.confid = ++sp->pp_seq;
sppp_cp_send (sp, PPP_LCP, LCP_CONF_REQ, sp->lcp.confid,
sizeof (opt), &opt);
sppp_set_timeout (sp, 2);
}
static void sppp_ipcp_open (struct sppp *sp)
{
sp->ipcp.confid = ++sp->pp_seq;
sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_REQ, sp->ipcp.confid, 0, NULL);
sppp_set_timeout (sp, 2);
}
/*
* Process PPP control protocol timeouts.
*/
static void sppp_cp_timeout (unsigned long arg)
{
struct sppp *sp = (struct sppp*) arg;
unsigned long flags;
spin_lock_irqsave(&sp->lock, flags);
sp->pp_flags &= ~PP_TIMO;
if (! (sp->pp_if->flags & IFF_UP) || (sp->pp_flags & PP_CISCO)) {
spin_unlock_irqrestore(&sp->lock, flags);
return;
}
switch (sp->lcp.state) {
case LCP_STATE_CLOSED:
/* No ACK for Configure-Request, retry. */
sppp_lcp_open (sp);
break;
case LCP_STATE_ACK_RCVD:
/* ACK got, but no Configure-Request for peer, retry. */
sppp_lcp_open (sp);
sp->lcp.state = LCP_STATE_CLOSED;
break;
case LCP_STATE_ACK_SENT:
/* ACK sent but no ACK for Configure-Request, retry. */
sppp_lcp_open (sp);
break;
case LCP_STATE_OPENED:
/* LCP is already OK, try IPCP. */
switch (sp->ipcp.state) {
case IPCP_STATE_CLOSED:
/* No ACK for Configure-Request, retry. */
sppp_ipcp_open (sp);
break;
case IPCP_STATE_ACK_RCVD:
/* ACK got, but no Configure-Request for peer, retry. */
sppp_ipcp_open (sp);
sp->ipcp.state = IPCP_STATE_CLOSED;
break;
case IPCP_STATE_ACK_SENT:
/* ACK sent but no ACK for Configure-Request, retry. */
sppp_ipcp_open (sp);
break;
case IPCP_STATE_OPENED:
/* IPCP is OK. */
break;
}
break;
}
spin_unlock_irqrestore(&sp->lock, flags);
sppp_flush_xmit();
}
static char *sppp_lcp_type_name (u8 type)
{
static char buf [8];
switch (type) {
case LCP_CONF_REQ: return ("conf-req");
case LCP_CONF_ACK: return ("conf-ack");
case LCP_CONF_NAK: return ("conf-nack");
case LCP_CONF_REJ: return ("conf-rej");
case LCP_TERM_REQ: return ("term-req");
case LCP_TERM_ACK: return ("term-ack");
case LCP_CODE_REJ: return ("code-rej");
case LCP_PROTO_REJ: return ("proto-rej");
case LCP_ECHO_REQ: return ("echo-req");
case LCP_ECHO_REPLY: return ("echo-reply");
case LCP_DISC_REQ: return ("discard-req");
}
sprintf (buf, "%xh", type);
return (buf);
}
static char *sppp_ipcp_type_name (u8 type)
{
static char buf [8];
switch (type) {
case IPCP_CONF_REQ: return ("conf-req");
case IPCP_CONF_ACK: return ("conf-ack");
case IPCP_CONF_NAK: return ("conf-nack");
case IPCP_CONF_REJ: return ("conf-rej");
case IPCP_TERM_REQ: return ("term-req");
case IPCP_TERM_ACK: return ("term-ack");
case IPCP_CODE_REJ: return ("code-rej");
}
sprintf (buf, "%xh", type);
return (buf);
}
static void sppp_print_bytes (u_char *p, u16 len)
{
printk (" %x", *p++);
while (--len > 0)
printk ("-%x", *p++);
}
/**
* sppp_rcv - receive and process a WAN PPP frame
* @skb: The buffer to process
* @dev: The device it arrived on
* @p: Unused
* @orig_dev: Unused
*
* Protocol glue. This drives the deferred processing mode the poorer
* cards use. This can be called directly by cards that do not have
* timing constraints but is normally called from the network layer
* after interrupt servicing to process frames queued via netif_rx.
*/
static int sppp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *p, struct net_device *orig_dev)
{
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
return NET_RX_DROP;
sppp_input(dev,skb);
return 0;
}
static struct packet_type sppp_packet_type = {
.type = __constant_htons(ETH_P_WAN_PPP),
.func = sppp_rcv,
};
static char banner[] __initdata =
KERN_INFO "Cronyx Ltd, Synchronous PPP and CISCO HDLC (c) 1994\n"
KERN_INFO "Linux port (c) 1998 Building Number Three Ltd & "
"Jan \"Yenya\" Kasprzak.\n";
static int __init sync_ppp_init(void)
{
if(debug)
debug=PP_DEBUG;
printk(banner);
skb_queue_head_init(&tx_queue);
dev_add_pack(&sppp_packet_type);
return 0;
}
static void __exit sync_ppp_cleanup(void)
{
dev_remove_pack(&sppp_packet_type);
}
module_init(sync_ppp_init);
module_exit(sync_ppp_cleanup);
module_param(debug, int, 0);
MODULE_LICENSE("GPL");
