ppp.c

arm平台上的uclinux系统全部源代码

/*  PPP for Linux
 *
 *  Michael Callahan <[e-mail]>
 *  Al Longyear <[e-mail]>
 *
 *  Dynamic PPP devices by Jim Freeman <[e-mail]>.
 *  ppp_tty_receive ``noisy-raise-bug'' fixed by Ove Ewerlid <[e-mail]>
 *
 *  ==FILEVERSION 970703==
 *
 *  NOTE TO MAINTAINERS:
 *     If you modify this file at all, please set the number above to the
 *     date of the modification as YYMMDD (year month day).
 *     ppp.c is shipped with a PPP distribution as well as with the kernel;
 *     if everyone increases the FILEVERSION number above, then scripts
 *     can do the right thing when deciding whether to install a new ppp.c
 *     file.  Don't change the format of that line otherwise, so the
 *     installation script can recognize it.
 */

/*
   Sources:

   slip.c

   RFC1331: The Point-to-Point Protocol (PPP) for the Transmission of
   Multi-protocol Datagrams over Point-to-Point Links

   RFC1332: IPCP

   ppp-2.0

   Flags for this module (any combination is acceptable for testing.):

   OPTIMIZE_FLAG_TIME - Number of jiffies to force sending of leading flag
			character. This is normally set to ((HZ * 3) / 2).
			This is 1.5 seconds. If zero then the leading
			flag is always sent.

   CHECK_CHARACTERS   - Enable the checking on all received characters for
			8 data bits, no parity. This adds a small amount of
			processing for each received character.
*/

#define OPTIMIZE_FLAG_TIME	((HZ * 3)/2)

#define CHECK_CHARACTERS	1
#define PPP_COMPRESS		1

#ifndef PPP_MAX_DEV
#define PPP_MAX_DEV	256
#endif

/* $Id: ppp.c,v 1.1.1.1 1999/11/15 13:42:34 vadim Exp $
 * Added dynamic allocation of channels to eliminate
 *   compiled-in limits on the number of channels.
 *
 * Dynamic channel allocation code Copyright 1995 Caldera, Inc.,
 *   released under the GNU General Public License Version 2.
 */

#include <linux/autoconf.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/sched.h>	/* to get the struct task_struct */
#include <linux/string.h>	/* used in new tty drivers */
#include <linux/signal.h>	/* used in new tty drivers */
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/segment.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/ioctl.h>

typedef struct sk_buff	     sk_buff;
#define skb_data(skb)	     ((__u8 *) (skb)->data)

#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/if_arp.h>
#include <net/slhc_vj.h>

#define fcstab ppp_crc16_table		/* Name of the table in the kernel */
#include <linux/ppp_defs.h>

#include <linux/socket.h>
#include <linux/if_ppp.h>
#include <linux/if_pppvar.h>

#undef	 PACKETPTR
#define	 PACKETPTR 1
#include <linux/ppp-comp.h>
#undef	 PACKETPTR

#define bsd_decompress	(*ppp->sc_rcomp->decompress)
#define bsd_compress	(*ppp->sc_xcomp->compress)

#ifndef PPP_IPX
#define PPP_IPX 0x2b  /* IPX protocol over PPP */
#endif

#ifndef PPP_LQR
#define PPP_LQR 0xc025	/* Link Quality Reporting Protocol */
#endif

static int ppp_register_compressor (struct compressor *cp);
static void ppp_unregister_compressor (struct compressor *cp);

/*
 * Local functions
 */

static struct compressor *find_compressor (int type);
static void ppp_init_ctrl_blk (register struct ppp *);
static void ppp_kick_tty (struct ppp *, struct ppp_buffer *bfr);
static int ppp_doframe (struct ppp *);
static struct ppp *ppp_alloc (void);
static struct ppp *ppp_find (int pid_value);
static void ppp_print_buffer (const __u8 *, const __u8 *, int);
extern inline void ppp_stuff_char (struct ppp *ppp,
				   register struct ppp_buffer *buf,
				   register __u8 chr);
extern inline int lock_buffer (register struct ppp_buffer *buf);

static int rcv_proto_ip         (struct ppp *, __u16, __u8 *, int);
static int rcv_proto_ipx        (struct ppp *, __u16, __u8 *, int);
static int rcv_proto_vjc_comp   (struct ppp *, __u16, __u8 *, int);
static int rcv_proto_vjc_uncomp (struct ppp *, __u16, __u8 *, int);
static int rcv_proto_unknown    (struct ppp *, __u16, __u8 *, int);
static int rcv_proto_lqr        (struct ppp *, __u16, __u8 *, int);
static void ppp_doframe_lower   (struct ppp *, __u8 *, int);
static int ppp_doframe          (struct ppp *);

extern int  ppp_bsd_compressor_init(void);
static void ppp_proto_ccp (struct ppp *ppp, __u8 *dp, int len, int rcvd);
static int  rcv_proto_ccp (struct ppp *, __u16, __u8 *, int);

#define ins_char(pbuf,c) (buf_base(pbuf) [(pbuf)->count++] = (__u8)(c))

#ifndef OPTIMIZE_FLAG_TIME
#define OPTIMIZE_FLAG_TIME	0
#endif

#ifndef PPP_MAX_DEV
#define PPP_MAX_DEV 256
#endif

/*
 * Parameters which may be changed via insmod.
 */

static int  flag_time = OPTIMIZE_FLAG_TIME;
static int  max_dev   = PPP_MAX_DEV;

/*
 * The "main" procedure to the ppp device
 */

int ppp_init (struct device *);

/*
 * Network device driver callback routines
 */

static int ppp_dev_open (struct device *);
static int ppp_dev_ioctl (struct device *dev, struct ifreq *ifr, int cmd);
static int ppp_dev_close (struct device *);
static int ppp_dev_xmit (sk_buff *, struct device *);
static struct enet_statistics *ppp_dev_stats (struct device *);
static int ppp_dev_header (sk_buff *, struct device *, __u16,
			   void *, void *, unsigned int);
static int ppp_dev_rebuild (void *eth, struct device *dev,
			     unsigned long raddr, struct sk_buff *skb);
/*
 * TTY callbacks
 */

static int ppp_tty_read (struct tty_struct *, struct file *, __u8 *,
			 unsigned int);
static int ppp_tty_write (struct tty_struct *, struct file *, const __u8 *,
			  unsigned int);
static int ppp_tty_ioctl (struct tty_struct *, struct file *, unsigned int,
			  unsigned long);
static int ppp_tty_select (struct tty_struct *tty, struct inode *inode,
		      struct file *filp, int sel_type, select_table * wait);
static int ppp_tty_open (struct tty_struct *);
static void ppp_tty_close (struct tty_struct *);
static int ppp_tty_room (struct tty_struct *tty);
static void ppp_tty_receive (struct tty_struct *tty, const __u8 * cp,
			     char *fp, int count);
static void ppp_tty_wakeup (struct tty_struct *tty);

#define CHECK_PPP(a)  if (!ppp->inuse) { printk (ppp_warning, __LINE__); return a;}
#define CHECK_PPP_VOID()  if (!ppp->inuse) { printk (ppp_warning, __LINE__); return;}

#define in_xmap(ppp,c)	(ppp->xmit_async_map[(c) >> 5] & (1 << ((c) & 0x1f)))
#define in_rmap(ppp,c)	((((unsigned int) (__u8) (c)) < 0x20) && \
			ppp->recv_async_map & (1 << (c)))

#define bset(p,b)	((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))

#define tty2ppp(tty)	((struct ppp *) (tty->disc_data))
#define dev2ppp(dev)	((struct ppp *) (dev->priv))
#define ppp2tty(ppp)	((struct tty_struct *) ppp->tty)
#define ppp2dev(ppp)	((struct device *) ppp->dev)

struct ppp_hdr {
	__u8 address;
	__u8 control;
	__u8 protocol[2];
};

#define PPP_HARD_HDR_LEN	(sizeof (struct ppp_hdr))

typedef struct  ppp_ctrl {
	struct ppp_ctrl *next;		/* Next structure in the list	*/
	char            name [8];	/* Name of the device		*/
	struct ppp      ppp;		/* PPP control table		*/
	struct device   dev;		/* Device information table	*/
} ppp_ctrl_t;

static ppp_ctrl_t *ppp_list = NULL;

#define ctl2ppp(ctl) (struct ppp *)    &ctl->ppp
#define ctl2dev(ctl) (struct device *) &ctl->dev
#undef  PPP_NRUNIT

/* Buffer types */
#define BUFFER_TYPE_DEV_RD	0  /* ppp read buffer       */
#define BUFFER_TYPE_TTY_WR	1  /* tty write buffer      */
#define BUFFER_TYPE_DEV_WR	2  /* ppp write buffer      */
#define BUFFER_TYPE_TTY_RD	3  /* tty read buffer       */
#define BUFFER_TYPE_VJ		4  /* vj compression buffer */

/* Define this string only once for all macro invocations */
static char ppp_warning[] = KERN_WARNING "PPP: ALERT! not INUSE! %d\n";

static char szVersion[]         = PPP_VERSION;
 
/*
 * Information for the protocol decoder
 */

typedef int (*pfn_proto)  (struct ppp *, __u16, __u8 *, int);

typedef struct ppp_proto_struct {
	int		proto;
	pfn_proto	func;
} ppp_proto_type;

static
ppp_proto_type proto_list[] = {
	{ PPP_IP,         rcv_proto_ip         },
	{ PPP_IPX,        rcv_proto_ipx        },
	{ PPP_VJC_COMP,   rcv_proto_vjc_comp   },
	{ PPP_VJC_UNCOMP, rcv_proto_vjc_uncomp },
	{ PPP_LQR,        rcv_proto_lqr        },
	{ PPP_CCP,        rcv_proto_ccp        },
	{ 0,              rcv_proto_unknown    }  /* !!! MUST BE LAST !!! */
};

__u16 ppp_crc16_table[256] =
{
	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

#ifdef CHECK_CHARACTERS
static __u32 paritytab[8] =
{
	0x96696996, 0x69969669, 0x69969669, 0x96696996,
	0x69969669, 0x96696996, 0x96696996, 0x69969669
};
#endif

/* local function to store a value into the LQR frame */
extern inline __u8 * store_long (register __u8 *p, register int value) {
	*p++ = (__u8) (value >> 24);
	*p++ = (__u8) (value >> 16);
	*p++ = (__u8) (value >>  8);
	*p++ = (__u8) value;
	return p;
}

/*************************************************************
 * INITIALIZATION
 *************************************************************/

/* This procedure is called once and once only to define who we are to
 * the operating system and the various procedures that it may use in
 * accessing the ppp protocol.
 */

static int
ppp_first_time (void)
{
	static struct tty_ldisc	ppp_ldisc;
	int    status;

	printk (KERN_INFO
		"PPP: version %s (dynamic channel allocation)"
		"\n", szVersion);

#ifndef MODULE /* slhc module logic has its own copyright announcement */
	printk (KERN_INFO
		"TCP compression code copyright 1989 Regents of the "
		"University of California\n");
#endif
	
	printk (KERN_INFO
		"PPP Dynamic channel allocation code copyright 1995 "
		"Caldera, Inc.\n");
/*
 * Register the tty discipline
 */	
	(void) memset (&ppp_ldisc, 0, sizeof (ppp_ldisc));
	ppp_ldisc.magic		= TTY_LDISC_MAGIC;
	ppp_ldisc.open		= ppp_tty_open;
	ppp_ldisc.close		= ppp_tty_close;
	ppp_ldisc.read		= ppp_tty_read;
	ppp_ldisc.write		= ppp_tty_write;
	ppp_ldisc.ioctl		= ppp_tty_ioctl;
	ppp_ldisc.select	= ppp_tty_select;
	ppp_ldisc.receive_room	= ppp_tty_room;
	ppp_ldisc.receive_buf	= ppp_tty_receive;
	ppp_ldisc.write_wakeup	= ppp_tty_wakeup;
	
	status = tty_register_ldisc (N_PPP, &ppp_ldisc);
	if (status == 0)
		printk (KERN_INFO "PPP line discipline registered.\n");
	else
		printk (KERN_ERR "error registering line discipline: %d\n",
			status);
	return status;
}

/*************************************************************
 * INITIALIZATION
 *************************************************************/

/* called when the device is actually created */

static int
ppp_init_dev (struct device *dev)
{
	int    indx;

	dev->hard_header      = ppp_dev_header;
	dev->rebuild_header   = ppp_dev_rebuild;
	dev->hard_header_len  = PPP_HARD_HDR_LEN;

	/* device INFO */
	dev->mtu              = PPP_MTU;
	dev->hard_start_xmit  = ppp_dev_xmit;
	dev->open             = ppp_dev_open;
	dev->stop             = ppp_dev_close;
	dev->get_stats        = ppp_dev_stats;
	dev->do_ioctl         = ppp_dev_ioctl;
	dev->addr_len         = 0;
	dev->tx_queue_len     = 10;
	dev->type             = ARPHRD_PPP;

	for (indx = 0; indx < DEV_NUMBUFFS; indx++)
		skb_queue_head_init (&dev->buffs[indx]);

	/* New-style flags */
#ifdef IFF_SOFTHEADERS
	/* Needed to make SOCK_PACKET work correctly in
	 * memory fussy kernels.
	 */
	dev->flags	= IFF_POINTOPOINT|IFF_SOFTHEADERS;
#else
	dev->flags      = IFF_POINTOPOINT;
#endif
	dev->family     = AF_INET;
	dev->pa_addr    = 0;
	dev->pa_brdaddr = 0;
	dev->pa_mask    = 0;
	dev->pa_alen    = 4; /* sizeof (__u32) */

	return 0;
}

/*
 * Local procedure to initialize the ppp structure
 */

static void
ppp_init_ctrl_blk (register struct ppp *ppp)
{
	ppp->magic  = PPP_MAGIC;
	ppp->toss   = 0xE0;
	ppp->escape = 0;

	ppp->flags  = 0;
	ppp->mtu    = PPP_MTU;
	ppp->mru    = PPP_MRU;

	memset (ppp->xmit_async_map, 0, sizeof (ppp->xmit_async_map));
	ppp->xmit_async_map[0] = 0xffffffff;
	ppp->xmit_async_map[3] = 0x60000000;
	ppp->recv_async_map    = 0x00000000;

	ppp->rbuf       = NULL;
	ppp->wbuf       = NULL;
	ppp->ubuf       = NULL;
	ppp->cbuf       = NULL;
	ppp->slcomp     = NULL;
	ppp->read_wait  = NULL;
	ppp->write_wait = NULL;
	ppp->last_xmit  = jiffies - flag_time;

	/* clear statistics */
	memset (&ppp->stats, '\0', sizeof (struct pppstat));

	/* Reset the demand dial information */
	ppp->ddinfo.xmit_idle=         /* time since last NP packet sent */
	ppp->ddinfo.recv_idle=jiffies; /* time since last NP packet received */

	/* PPP compression data */
	ppp->sc_xc_state =
	ppp->sc_rc_state = NULL;
}

static struct symbol_table ppp_syms = {
#include <linux/symtab_begin.h>
	X(ppp_register_compressor),
	X(ppp_unregister_compressor),
	X(ppp_crc16_table),
#include <linux/symtab_end.h>
};

/* called at boot/load time for each ppp device defined in the kernel */

#ifndef MODULE
int
ppp_init (struct device *dev)
{
	static int first_time = 1;
	int    answer = 0;

	if (first_time) {
		first_time = 0;
		answer     = ppp_first_time();
		if (answer == 0)
			(void) register_symtab (&ppp_syms);
	}
	if (answer == 0)
		answer = -ENODEV;
	return answer;
}
#endif

/*
 * Routine to allocate a buffer for later use by the driver.
 */

static struct ppp_buffer *
ppp_alloc_buf (int size, int type)
{
	struct ppp_buffer *buf;

	buf = (struct ppp_buffer *) kmalloc (size + sizeof (struct ppp_buffer),
					     GFP_ATOMIC);

	if (buf != NULL) {
		buf->size   = size - 1;	/* Mask for the buffer size */
		buf->type   = type;
		buf->locked = 0;
		buf->count  = 0;
		buf->head   = 0;
		buf->tail   = 0;
		buf->fcs    = PPP_INITFCS;

	}
	return (buf);
}

/*
 * Routine to release the allocated buffer.
 */

static void
ppp_free_buf (struct ppp_buffer *ptr)
{
	if (ptr != NULL)
		kfree (ptr);
}

/*
 * Lock the indicated transmit buffer
 */