ppp_ahdlc.c

经典的ppp程序

/*
 * ppp_ahdlc.c - STREAMS module for doing PPP asynchronous HDLC.
 *
 * Re-written by Adi Masputra <[e-mail]>, based on 
 * the original ppp_ahdlc.c
 *
 * Copyright (c) 2000 by Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, provided that the above copyright
 * notice appears in all copies.  
 *
 * SUN MAKES NO REPRESENTATION OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES
 *
 * Copyright (c) 1994 The Australian National University.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, provided that the above copyright
 * notice appears in all copies.  This software is provided without any
 * warranty, express or implied. The Australian National University
 * makes no representations about the suitability of this software for
 * any purpose.
 *
 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 * OR MODIFICATIONS.
 *
 * $Id: ppp_ahdlc.c,v 1.16 2000/03/06 19:38:12 masputra Exp $
 */

/*
 * This file is used under Solaris 2, SVR4, SunOS 4, and Digital UNIX.
 */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stream.h>
#include <sys/errno.h>

#ifdef SVR4
#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/ddi.h>
#else
#include <sys/user.h>
#ifdef __osf__
#include <sys/cmn_err.h>
#endif
#endif /* SVR4 */

#include <net/ppp_defs.h>
#include <net/pppio.h>
#include "ppp_mod.h"

/*
 * Right now, mutex is only enabled for Solaris 2.x
 */
#if defined(SOL2)
#define USE_MUTEX
#endif /* SOL2 */

/*
 * intpointer_t and uintpointer_t are signed and unsigned integer types 
 * large enough to hold any data pointer; that is, data pointers can be 
 * assigned into or from these integer types without losing precision.
 * On recent Solaris releases, these types are defined in sys/int_types.h,
 * but not on SunOS 4.x or the earlier Solaris versions.
 */
#if defined(_LP64) || defined(_I32LPx)
typedef long                    intpointer_t;
typedef unsigned long           uintpointer_t;
#else
typedef int                     intpointer_t;
typedef unsigned int            uintpointer_t;
#endif

MOD_OPEN_DECL(ahdlc_open);
MOD_CLOSE_DECL(ahdlc_close);
static int ahdlc_wput __P((queue_t *, mblk_t *));
static int ahdlc_rput __P((queue_t *, mblk_t *));
static void ahdlc_encode __P((queue_t *, mblk_t *));
static void ahdlc_decode __P((queue_t *, mblk_t *));
static int msg_byte __P((mblk_t *, unsigned int));

#if defined(SOL2)
/*
 * Don't send HDLC start flag is last transmit is within 1.5 seconds -
 * FLAG_TIME is defined is microseconds
 */
#define FLAG_TIME   1500
#define ABS(x)	    (x >= 0 ? x : (-x))
#endif /* SOL2 */

/*
 * Extract byte i of message mp 
 */
#define MSG_BYTE(mp, i)	((i) < (mp)->b_wptr - (mp)->b_rptr? (mp)->b_rptr[i]: \
			 msg_byte((mp), (i)))

/* 
 * Is this LCP packet one we have to transmit using LCP defaults? 
 */
#define LCP_USE_DFLT(mp)	(1 <= (code = MSG_BYTE((mp), 4)) && code <= 7)

/*
 * Standard STREAMS declarations
 */
static struct module_info minfo = {
    0x7d23, "ppp_ahdl", 0, INFPSZ, 32768, 512
};

static struct qinit rinit = {
    ahdlc_rput, NULL, ahdlc_open, ahdlc_close, NULL, &minfo, NULL
};

static struct qinit winit = {
    ahdlc_wput, NULL, NULL, NULL, NULL, &minfo, NULL
};

#if defined(SVR4) && !defined(SOL2)
int phdldevflag = 0;
#define ppp_ahdlcinfo phdlinfo
#endif /* defined(SVR4) && !defined(SOL2) */

struct streamtab ppp_ahdlcinfo = {
    &rinit,			    /* ptr to st_rdinit */
    &winit,			    /* ptr to st_wrinit */
    NULL,			    /* ptr to st_muxrinit */
    NULL,			    /* ptr to st_muxwinit */
#if defined(SUNOS4)
    NULL			    /* ptr to ptr to st_modlist */
#endif /* SUNOS4 */
};

#if defined(SUNOS4)
int ppp_ahdlc_count = 0;	    /* open counter */
#endif /* SUNOS4 */

/*
 * Per-stream state structure
 */
typedef struct ahdlc_state {
#if defined(USE_MUTEX)
    kmutex_t	    lock;		    /* lock for this structure */
#endif /* USE_MUTEX */
    int		    flags;		    /* link flags */
    mblk_t	    *rx_buf;		    /* ptr to receive buffer */
    int		    rx_buf_size;	    /* receive buffer size */
    ushort_t	    infcs;		    /* calculated rx HDLC FCS */
    u_int32_t	    xaccm[8];		    /* 256-bit xmit ACCM */
    u_int32_t	    raccm;		    /* 32-bit rcv ACCM */
    int		    mtu;		    /* interface MTU */
    int		    mru;		    /* link MRU */
    int		    unit;		    /* current PPP unit number */
    struct pppstat  stats;		    /* statistic structure */
#if defined(SOL2)
    clock_t	    flag_time;		    /* time in usec between flags */
    clock_t	    lbolt;		    /* last updated lbolt */
#endif /* SOL2 */
} ahdlc_state_t;

/*
 * Values for flags 
 */
#define ESCAPED		0x100	/* last saw escape char on input */
#define IFLUSH		0x200	/* flushing input due to error */

/* 
 * RCV_B7_1, etc., defined in net/pppio.h, are stored in flags also. 
 */
#define RCV_FLAGS	(RCV_B7_1|RCV_B7_0|RCV_ODDP|RCV_EVNP)

/*
 * FCS lookup table as calculated by genfcstab.
 */
static u_short fcstab[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
};

static u_int32_t paritytab[8] =
{
	0x96696996, 0x69969669, 0x69969669, 0x96696996,
	0x69969669, 0x96696996, 0x96696996, 0x69969669
};

/*
 * STREAMS module open (entry) point
 */
MOD_OPEN(ahdlc_open)
{
    ahdlc_state_t   *state;

    /*
     * Return if it's already opened
     */
    if (q->q_ptr) {
	return 0;
    }

    /*
     * This can only be opened as a module
     */
    if (sflag != MODOPEN) {
	return 0;
    }

    state = (ahdlc_state_t *) ALLOC_NOSLEEP(sizeof(ahdlc_state_t));
    if (state == 0)
	OPEN_ERROR(ENOSR);
    bzero((caddr_t) state, sizeof(ahdlc_state_t));

    q->q_ptr	 = (caddr_t) state;
    WR(q)->q_ptr = (caddr_t) state;

#if defined(USE_MUTEX)
    mutex_init(&state->lock, NULL, MUTEX_DEFAULT, NULL);
    mutex_enter(&state->lock);
#endif /* USE_MUTEX */

    state->xaccm[0] = ~0;	    /* escape 0x00 through 0x1f */
    state->xaccm[3] = 0x60000000;   /* escape 0x7d and 0x7e */
    state->mru	    = PPP_MRU;	    /* default of 1500 bytes */
#if defined(SOL2)
    state->flag_time = drv_usectohz(FLAG_TIME);
#endif /* SOL2 */

#if defined(USE_MUTEX)
    mutex_exit(&state->lock);
#endif /* USE_MUTEX */	

#if defined(SUNOS4)
    ppp_ahdlc_count++;
#endif /* SUNOS4 */

    qprocson(q);
    
    return 0;
}

/*
 * STREAMS module close (exit) point
 */
MOD_CLOSE(ahdlc_close)
{
    ahdlc_state_t   *state;

    qprocsoff(q);

    state = (ahdlc_state_t *) q->q_ptr;

    if (state == 0) {
	DPRINT("state == 0 in ahdlc_close\n");
	return 0;
    }

#if defined(USE_MUTEX)
    mutex_enter(&state->lock);
#endif /* USE_MUTEX */

    if (state->rx_buf != 0) {
	freemsg(state->rx_buf);
	state->rx_buf = 0;
    }

#if defined(USE_MUTEX)
    mutex_exit(&state->lock);
    mutex_destroy(&state->lock);
#endif /* USE_MUTEX */

    FREE(q->q_ptr, sizeof(ahdlc_state_t));
    q->q_ptr	     = NULL;
    OTHERQ(q)->q_ptr = NULL;

#if defined(SUNOS4)
    if (ppp_ahdlc_count)
	ppp_ahdlc_count--;
#endif /* SUNOS4 */
    
    return 0;
}

/*
 * Write side put routine
 */
static int
ahdlc_wput(q, mp)
    queue_t	*q;
    mblk_t	*mp;
{
    ahdlc_state_t  	*state;
    struct iocblk  	*iop;
    int		   	error;
    mblk_t	   	*np;
    struct ppp_stats	*psp;

    state = (ahdlc_state_t *) q->q_ptr;
    if (state == 0) {
	DPRINT("state == 0 in ahdlc_wput\n");
	freemsg(mp);
	return 0;
    }

    switch (mp->b_datap->db_type) {
    case M_DATA:
	/*
	 * A data packet - do character-stuffing and FCS, and
	 * send it onwards.
	 */
	ahdlc_encode(q, mp);
	freemsg(mp);
	break;

    case M_IOCTL:
	iop = (struct iocblk *) mp->b_rptr;
	error = EINVAL;
	switch (iop->ioc_cmd) {
	case PPPIO_XACCM:
	    if ((iop->ioc_count < sizeof(u_int32_t)) || 
		(iop->ioc_count > sizeof(ext_accm))) {
		break;
	    }
	    if (mp->b_cont == 0) {
		DPRINT1("ahdlc_wput/%d: PPPIO_XACCM b_cont = 0!\n", state->unit);
		break;
	    }
#if defined(USE_MUTEX)
	    mutex_enter(&state->lock);
#endif /* USE_MUTEX */
	    bcopy((caddr_t)mp->b_cont->b_rptr, (caddr_t)state->xaccm,
		  iop->ioc_count);
	    state->xaccm[2] &= ~0x40000000;	/* don't escape 0x5e */
	    state->xaccm[3] |= 0x60000000;	/* do escape 0x7d, 0x7e */
#if defined(USE_MUTEX)
	    mutex_exit(&state->lock);
#endif /* USE_MUTEX */
	    iop->ioc_count = 0;
	    error = 0;
	    break;

	case PPPIO_RACCM:
	    if (iop->ioc_count != sizeof(u_int32_t))
		break;
	    if (mp->b_cont == 0) {
		DPRINT1("ahdlc_wput/%d: PPPIO_RACCM b_cont = 0!\n", state->unit);
		break;
	    }
#if defined(USE_MUTEX)
	    mutex_enter(&state->lock);
#endif /* USE_MUTEX */
	    bcopy((caddr_t)mp->b_cont->b_rptr, (caddr_t)&state->raccm,
		  sizeof(u_int32_t));
#if defined(USE_MUTEX)
	    mutex_exit(&state->lock);
#endif /* USE_MUTEX */
	    iop->ioc_count = 0;
	    error = 0;
	    break;

	case PPPIO_GCLEAN:
	    np = allocb(sizeof(int), BPRI_HI);
	    if (np == 0) {
		error = ENOSR;
		break;
	    }
	    if (mp->b_cont != 0)
		freemsg(mp->b_cont);
	    mp->b_cont = np;
#if defined(USE_MUTEX)
	    mutex_enter(&state->lock);
#endif /* USE_MUTEX */
	    *(int *)np->b_wptr = state->flags & RCV_FLAGS;
#if defined(USE_MUTEX)
	    mutex_exit(&state->lock);
#endif /* USE_MUTEX */
	    np->b_wptr += sizeof(int);
	    iop->ioc_count = sizeof(int);
	    error = 0;
	    break;

	case PPPIO_GETSTAT:
	    np = allocb(sizeof(struct ppp_stats), BPRI_HI);
	    if (np == 0) {
		error = ENOSR;
		break;
	    }
	    if (mp->b_cont != 0)
		freemsg(mp->b_cont);
	    mp->b_cont = np;
	    psp = (struct ppp_stats *) np->b_wptr;
	    np->b_wptr += sizeof(struct ppp_stats);
	    bzero((caddr_t)psp, sizeof(struct ppp_stats));
	    psp->p = state->stats;
	    iop->ioc_count = sizeof(struct ppp_stats);