ccp.c

eCos操作系统源码

//==========================================================================
//
//      src/ccp.c
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Portions created by Nick Garnett are
// Copyright (C) 2003 eCosCentric Ltd.
//
// eCos 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 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * ccp.c - PPP Compression Control Protocol.
 *
 * 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 HAVE 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.
 */

#ifndef lint
//static char rcsid[] = "$FreeBSD: src/usr.sbin/pppd/ccp.c,v 1.10 1999/08/28 01:19:00 peter Exp $";
#endif

#include <string.h>
#include <cyg/ppp/syslog.h>
#include <sys/ioctl.h>
#include <sys/types.h>

#include "cyg/ppp/pppd.h"
#include "cyg/ppp/fsm.h"
#include "cyg/ppp/ccp.h"
#include <cyg/ppp/net/ppp_comp.h>

/*
 * Protocol entry points from main code.
 */
static void ccp_init __P((int unit));
static void ccp_open __P((int unit));
static void ccp_close __P((int unit, char *));
static void ccp_lowerup __P((int unit));
static void ccp_lowerdown __P((int));
static void ccp_input __P((int unit, u_char *pkt, int len));
static void ccp_protrej __P((int unit));
static int  ccp_printpkt __P((u_char *pkt, int len,
			      void (*printer) __P((void *, char *, ...)),
			      void *arg));
static void ccp_datainput __P((int unit, u_char *pkt, int len));

struct protent ccp_protent = {
    PPP_CCP,
    ccp_init,
    ccp_input,
    ccp_protrej,
    ccp_lowerup,
    ccp_lowerdown,
    ccp_open,
    ccp_close,
    ccp_printpkt,
    ccp_datainput,
    1,
    "CCP",
    NULL,
    NULL,
    NULL
};

fsm ccp_fsm[NUM_PPP];
ccp_options ccp_wantoptions[NUM_PPP];	/* what to request the peer to use */
ccp_options ccp_gotoptions[NUM_PPP];	/* what the peer agreed to do */
ccp_options ccp_allowoptions[NUM_PPP];	/* what we'll agree to do */
ccp_options ccp_hisoptions[NUM_PPP];	/* what we agreed to do */

/*
 * Callbacks for fsm code.
 */
static void ccp_resetci __P((fsm *));
static int  ccp_cilen __P((fsm *));
static void ccp_addci __P((fsm *, u_char *, int *));
static int  ccp_ackci __P((fsm *, u_char *, int));
static int  ccp_nakci __P((fsm *, u_char *, int));
static int  ccp_rejci __P((fsm *, u_char *, int));
static int  ccp_reqci __P((fsm *, u_char *, int *, int));
static void ccp_up __P((fsm *));
static void ccp_down __P((fsm *));
static int  ccp_extcode __P((fsm *, int, int, u_char *, int));
static void ccp_rack_timeout __P((void *));
static char *method_name __P((ccp_options *, ccp_options *));

static fsm_callbacks ccp_callbacks = {
    ccp_resetci,
    ccp_cilen,
    ccp_addci,
    ccp_ackci,
    ccp_nakci,
    ccp_rejci,
    ccp_reqci,
    ccp_up,
    ccp_down,
    NULL,
    NULL,
    NULL,
    NULL,
    ccp_extcode,
    "CCP"
};

/*
 * Do we want / did we get any compression?
 */
#define ANY_COMPRESS(opt)	((opt).deflate || (opt).bsd_compress \
				 || (opt).predictor_1 || (opt).predictor_2)

/*
 * Local state (mainly for handling reset-reqs and reset-acks).
 */
static int ccp_localstate[NUM_PPP];
#define RACK_PENDING	1	/* waiting for reset-ack */
#define RREQ_REPEAT	2	/* send another reset-req if no reset-ack */

#define RACKTIMEOUT	1	/* second */

static int all_rejected[NUM_PPP];	/* we rejected all peer's options */

/*
 * ccp_init - initialize CCP.
 */
static void
ccp_init(unit)
    int unit;
{
    fsm *f = &ccp_fsm[unit];

    f->unit = unit;
    f->protocol = PPP_CCP;
    f->callbacks = &ccp_callbacks;
    fsm_init(f);

    memset(&ccp_wantoptions[unit],  0, sizeof(ccp_options));
    memset(&ccp_gotoptions[unit],   0, sizeof(ccp_options));
    memset(&ccp_allowoptions[unit], 0, sizeof(ccp_options));
    memset(&ccp_hisoptions[unit],   0, sizeof(ccp_options));

    ccp_wantoptions[0].deflate = 1;
    ccp_wantoptions[0].deflate_size = DEFLATE_MAX_SIZE;
    ccp_wantoptions[0].deflate_correct = 1;
    ccp_wantoptions[0].deflate_draft = 1;
    ccp_allowoptions[0].deflate = 1;
    ccp_allowoptions[0].deflate_size = DEFLATE_MAX_SIZE;
    ccp_allowoptions[0].deflate_correct = 1;
    ccp_allowoptions[0].deflate_draft = 1;

    ccp_wantoptions[0].bsd_compress = 1;
    ccp_wantoptions[0].bsd_bits = BSD_MAX_BITS;
    ccp_allowoptions[0].bsd_compress = 1;
    ccp_allowoptions[0].bsd_bits = BSD_MAX_BITS;

    ccp_allowoptions[0].predictor_1 = 1;
}

/*
 * ccp_open - CCP is allowed to come up.
 */
static void
ccp_open(unit)
    int unit;
{
    fsm *f = &ccp_fsm[unit];

    if (f->state != OPENED)
	ccp_flags_set(unit, 1, 0);

    /*
     * Find out which compressors the kernel supports before
     * deciding whether to open in silent mode.
     */
    ccp_resetci(f);
    if (!ANY_COMPRESS(ccp_gotoptions[unit]))
	f->flags |= OPT_SILENT;

    fsm_open(f);
}

/*
 * ccp_close - Terminate CCP.
 */
static void
ccp_close(unit, reason)
    int unit;
    char *reason;
{
    ccp_flags_set(unit, 0, 0);
    fsm_close(&ccp_fsm[unit], reason);
}

/*
 * ccp_lowerup - we may now transmit CCP packets.
 */
static void
ccp_lowerup(unit)
    int unit;
{
    fsm_lowerup(&ccp_fsm[unit]);
}

/*
 * ccp_lowerdown - we may not transmit CCP packets.
 */
static void
ccp_lowerdown(unit)
    int unit;
{
    fsm_lowerdown(&ccp_fsm[unit]);
}

/*
 * ccp_input - process a received CCP packet.
 */
static void
ccp_input(unit, p, len)
    int unit;
    u_char *p;
    int len;
{
    fsm *f = &ccp_fsm[unit];
    int oldstate;

    /*
     * Check for a terminate-request so we can print a message.
     */
    oldstate = f->state;
    fsm_input(f, p, len);
    if (oldstate == OPENED && p[0] == TERMREQ && f->state != OPENED)
	syslog(LOG_NOTICE, "Compression disabled by peer.");

    /*
     * If we get a terminate-ack and we're not asking for compression,
     * close CCP.
     */
    if (oldstate == REQSENT && p[0] == TERMACK
	&& !ANY_COMPRESS(ccp_gotoptions[unit]))
	ccp_close(unit, "No compression negotiated");
}

/*
 * Handle a CCP-specific code.
 */
static int
ccp_extcode(f, code, id, p, len)
    fsm *f;
    int code, id;
    u_char *p;
    int len;
{
    switch (code) {
    case CCP_RESETREQ:
	if (f->state != OPENED)
	    break;
	/* send a reset-ack, which the transmitter will see and
	   reset its compression state. */
	fsm_sdata(f, CCP_RESETACK, id, NULL, 0);
	break;

    case CCP_RESETACK:
	if (ccp_localstate[f->unit] & RACK_PENDING && id == f->reqid) {
	    ccp_localstate[f->unit] &= ~(RACK_PENDING | RREQ_REPEAT);
	    UNTIMEOUT(ccp_rack_timeout, f);
	}
	break;

    default:
	return 0;
    }

    return 1;
}

/*
 * ccp_protrej - peer doesn't talk CCP.
 */
static void
ccp_protrej(unit)
    int unit;
{
    ccp_flags_set(unit, 0, 0);
    fsm_lowerdown(&ccp_fsm[unit]);
}

/*
 * ccp_resetci - initialize at start of negotiation.
 */
static void
ccp_resetci(f)
    fsm *f;
{
    ccp_options *go = &ccp_gotoptions[f->unit];
    u_char opt_buf[16];

    *go = ccp_wantoptions[f->unit];
    all_rejected[f->unit] = 0;

    /*
     * Check whether the kernel knows about the various
     * compression methods we might request.
     */
    if (go->bsd_compress) {
	opt_buf[0] = CI_BSD_COMPRESS;
	opt_buf[1] = CILEN_BSD_COMPRESS;
	opt_buf[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, BSD_MIN_BITS);
	if (ccp_test(f->unit, opt_buf, CILEN_BSD_COMPRESS, 0) <= 0)
	    go->bsd_compress = 0;
    }
    if (go->deflate) {
	if (go->deflate_correct) {
	    opt_buf[0] = CI_DEFLATE;
	    opt_buf[1] = CILEN_DEFLATE;
	    opt_buf[2] = DEFLATE_MAKE_OPT(DEFLATE_MIN_SIZE);
	    opt_buf[3] = DEFLATE_CHK_SEQUENCE;
	    if (ccp_test(f->unit, opt_buf, CILEN_DEFLATE, 0) <= 0)
		go->deflate_correct = 0;
	}
	if (go->deflate_draft) {
	    opt_buf[0] = CI_DEFLATE_DRAFT;
	    opt_buf[1] = CILEN_DEFLATE;
	    opt_buf[2] = DEFLATE_MAKE_OPT(DEFLATE_MIN_SIZE);
	    opt_buf[3] = DEFLATE_CHK_SEQUENCE;
	    if (ccp_test(f->unit, opt_buf, CILEN_DEFLATE, 0) <= 0)
		go->deflate_draft = 0;
	}
	if (!go->deflate_correct && !go->deflate_draft)
	    go->deflate = 0;
    }
    if (go->predictor_1) {
	opt_buf[0] = CI_PREDICTOR_1;
	opt_buf[1] = CILEN_PREDICTOR_1;
	if (ccp_test(f->unit, opt_buf, CILEN_PREDICTOR_1, 0) <= 0)
	    go->predictor_1 = 0;
    }
    if (go->predictor_2) {
	opt_buf[0] = CI_PREDICTOR_2;
	opt_buf[1] = CILEN_PREDICTOR_2;
	if (ccp_test(f->unit, opt_buf, CILEN_PREDICTOR_2, 0) <= 0)
	    go->predictor_2 = 0;
    }
}

/*
 * ccp_cilen - Return total length of our configuration info.
 */
static int
ccp_cilen(f)
    fsm *f;
{
    ccp_options *go = &ccp_gotoptions[f->unit];

    return (go->bsd_compress? CILEN_BSD_COMPRESS: 0)
	+ (go->deflate? CILEN_DEFLATE: 0)
	+ (go->predictor_1? CILEN_PREDICTOR_1: 0)
	+ (go->predictor_2? CILEN_PREDICTOR_2: 0);
}

/*
 * ccp_addci - put our requests in a packet.
 */
static void
ccp_addci(f, p, lenp)
    fsm *f;
    u_char *p;
    int *lenp;
{
    int res;
    ccp_options *go = &ccp_gotoptions[f->unit];
    u_char *p0 = p;

    /*
     * Add the compression types that we can receive, in decreasing
     * preference order.  Get the kernel to allocate the first one
     * in case it gets Acked.
     */
    if (go->deflate) {
	p[0] = go->deflate_correct? CI_DEFLATE: CI_DEFLATE_DRAFT;
	p[1] = CILEN_DEFLATE;
	p[2] = DEFLATE_MAKE_OPT(go->deflate_size);
	p[3] = DEFLATE_CHK_SEQUENCE;
	for (;;) {
	    res = ccp_test(f->unit, p, CILEN_DEFLATE, 0);
	    if (res > 0) {
		p += CILEN_DEFLATE;
		break;
	    }
	    if (res < 0 || go->deflate_size <= DEFLATE_MIN_SIZE) {
		go->deflate = 0;
		break;
	    }
	    --go->deflate_size;
	    p[2] = DEFLATE_MAKE_OPT(go->deflate_size);
	}
	if (p != p0 && go->deflate_correct && go->deflate_draft) {
	    p[0] = CI_DEFLATE_DRAFT;
	    p[1] = CILEN_DEFLATE;
	    p[2] = p[2 - CILEN_DEFLATE];
	    p[3] = DEFLATE_CHK_SEQUENCE;
	    p += CILEN_DEFLATE;
	}
    }
    if (go->bsd_compress) {
	p[0] = CI_BSD_COMPRESS;
	p[1] = CILEN_BSD_COMPRESS;
	p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
	if (p != p0) {
	    p += CILEN_BSD_COMPRESS;	/* not the first option */
	} else {
	    for (;;) {
		res = ccp_test(f->unit, p, CILEN_BSD_COMPRESS, 0);
		if (res > 0) {
		    p += CILEN_BSD_COMPRESS;
		    break;
		}
		if (res < 0 || go->bsd_bits <= BSD_MIN_BITS) {
		    go->bsd_compress = 0;
		    break;
		}
		--go->bsd_bits;
		p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
	    }
	}
    }
    /* XXX Should Predictor 2 be preferable to Predictor 1? */
    if (go->predictor_1) {
	p[0] = CI_PREDICTOR_1;
	p[1] = CILEN_PREDICTOR_1;
	if (p == p0 && ccp_test(f->unit, p, CILEN_PREDICTOR_1, 0) <= 0) {
	    go->predictor_1 = 0;
	} else {
	    p += CILEN_PREDICTOR_1;
	}
    }
    if (go->predictor_2) {
	p[0] = CI_PREDICTOR_2;
	p[1] = CILEN_PREDICTOR_2;
	if (p == p0 && ccp_test(f->unit, p, CILEN_PREDICTOR_2, 0) <= 0) {
	    go->predictor_2 = 0;
	} else {
	    p += CILEN_PREDICTOR_2;
	}
    }

    go->method = (p > p0)? p0[0]: -1;

    *lenp = p - p0;
}

/*
 * ccp_ackci - process a received configure-ack, and return
 * 1 iff the packet was OK.
 */
static int
ccp_ackci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ccp_options *go = &ccp_gotoptions[f->unit];
    u_char *p0 = p;

    if (go->deflate) {
	if (len < CILEN_DEFLATE
	    || p[0] != (go->deflate_correct? CI_DEFLATE: CI_DEFLATE_DRAFT)
	    || p[1] != CILEN_DEFLATE
	    || p[2] != DEFLATE_MAKE_OPT(go->deflate_size)
	    || p[3] != DEFLATE_CHK_SEQUENCE)
	    return 0;
	p += CILEN_DEFLATE;
	len -= CILEN_DEFLATE;
	/* XXX Cope with first/fast ack */
	if (len == 0)
	    return 1;
	if (go->deflate_correct && go->deflate_draft) {
	    if (len < CILEN_DEFLATE
		|| p[0] != CI_DEFLATE_DRAFT
		|| p[1] != CILEN_DEFLATE
		|| p[2] != DEFLATE_MAKE_OPT(go->deflate_size)
		|| p[3] != DEFLATE_CHK_SEQUENCE)
		return 0;
	    p += CILEN_DEFLATE;
	    len -= CILEN_DEFLATE;
	}
    }
    if (go->bsd_compress) {
	if (len < CILEN_BSD_COMPRESS
	    || p[0] != CI_BSD_COMPRESS || p[1] != CILEN_BSD_COMPRESS
	    || p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
	    return 0;
	p += CILEN_BSD_COMPRESS;
	len -= CILEN_BSD_COMPRESS;
	/* XXX Cope with first/fast ack */
	if (p == p0 && len == 0)
	    return 1;
    }
    if (go->predictor_1) {
	if (len < CILEN_PREDICTOR_1
	    || p[0] != CI_PREDICTOR_1 || p[1] != CILEN_PREDICTOR_1)
	    return 0;
	p += CILEN_PREDICTOR_1;
	len -= CILEN_PREDICTOR_1;
	/* XXX Cope with first/fast ack */
	if (p == p0 && len == 0)
	    return 1;
    }
    if (go->predictor_2) {
	if (len < CILEN_PREDICTOR_2
	    || p[0] != CI_PREDICTOR_2 || p[1] != CILEN_PREDICTOR_2)
	    return 0;
	p += CILEN_PREDICTOR_2;
	len -= CILEN_PREDICTOR_2;
	/* XXX Cope with first/fast ack */
	if (p == p0 && len == 0)
	    return 1;
    }

    if (len != 0)
	return 0;
    return 1;
}

/*