text: /*** WARNING - THIS HAS NEVER BEEN FINISHED ***/
  /*****************************************************************************
  * chap.c - Network Challenge Handshake Authentication Protocol program file.
  *
  * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
  * portions Copyright (c) 1997 by Global Election Systems Inc.
  *
  * The authors hereby grant permission to use, copy, modify, distribute,
  * and license this software and its documentation for any purpose, provided
  * that existing copyright notices are retained in all copies and that this
  * notice and the following disclaimer are included verbatim in any 
  * distributions. No written agreement, license, or royalty fee is required
  * for any of the authorized uses.
  *
  * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
  * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  * REVISION HISTORY
  *
  * 03-01-01 Marc Boucher <marc@mbsi.ca>
  *   Ported to lwIP.
  * 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
  *   Original based on BSD chap.c.
  *****************************************************************************/
  /*
   * chap.c - Challenge Handshake Authentication Protocol.
   *
   * Copyright (c) 1993 The Australian National University.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms are permitted
   * provided that the above copyright notice and this paragraph are
   * duplicated in all such forms and that any documentation,
   * advertising materials, and other materials related to such
   * distribution and use acknowledge that the software was developed
   * by the Australian National University.  The name of the University
   * may not be used to endorse or promote products derived from this
   * software without specific prior written permission.
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
   * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   *
   * Copyright (c) 1991 Gregory M. Christy.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms are permitted
   * provided that the above copyright notice and this paragraph are
   * duplicated in all such forms and that any documentation,
   * advertising materials, and other materials related to such
   * distribution and use acknowledge that the software was developed
   * by Gregory M. Christy.  The name of the author may not be used to
   * endorse or promote products derived from this software without
   * specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
   * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   */
  
  #include "lwip\opt.h"
  
  #if PPP_SUPPORT  /* don't build if not configured for use in lwipopts.h */
  
  #if CHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
  
  #include "ppp.h"
  #include "pppdebug.h"
  
  #include "magic.h"
  #include "randm.h"
  #include "auth.h"
  #include "md5.h"
  #include "chap.h"
  #include "chpms.h"
  
  #include <string.h>
  
  /*************************/
  /*** LOCAL DEFINITIONS ***/
  /*************************/
  
  
  /************************/
  /*** LOCAL DATA TYPES ***/
  /************************/
  
  
  /***********************************/
  /*** LOCAL FUNCTION DECLARATIONS ***/
  /***********************************/
  /*
   * Protocol entry points.
   */
  static void ChapInit (int);
  static void ChapLowerUp (int);
  static void ChapLowerDown (int);
  static void ChapInput (int, u_char *, int);
  static void ChapProtocolReject (int);
  #if 0
  static int  ChapPrintPkt (u_char *, int, void (*) (void *, char *, ...), void *);
  #endif
  
  static void ChapChallengeTimeout (void *);
  static void ChapResponseTimeout (void *);
  static void ChapReceiveChallenge (chap_state *, u_char *, int, int);
  static void ChapRechallenge (void *);
  static void ChapReceiveResponse (chap_state *, u_char *, int, int);
  static void ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len);
  static void ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len);
  static void ChapSendStatus (chap_state *, int);
  static void ChapSendChallenge (chap_state *);
  static void ChapSendResponse (chap_state *);
  static void ChapGenChallenge (chap_state *);
  
  
  /******************************/
  /*** PUBLIC DATA STRUCTURES ***/
  /******************************/
  chap_state chap[NUM_PPP]; /* CHAP state; one for each unit */
  
  struct protent chap_protent = {
    PPP_CHAP,
    ChapInit,
    ChapInput,
    ChapProtocolReject,
    ChapLowerUp,
    ChapLowerDown,
    NULL,
    NULL,
  #if 0
    ChapPrintPkt,
    NULL,
  #endif
    1,
    "CHAP",
  #if 0
    NULL,
    NULL,
    NULL
  #endif
  };
  
  
  /***********************************/
  /*** PUBLIC FUNCTION DEFINITIONS ***/
  /***********************************/
  /*
   * ChapAuthWithPeer - Authenticate us with our peer (start client).
   *
   */
  void
  ChapAuthWithPeer(int unit, char *our_name, int digest)
  {
    chap_state *cstate = &chap[unit];
  
    cstate->resp_name = our_name;
    cstate->resp_type = digest;
  
    if (cstate->clientstate == CHAPCS_INITIAL ||
        cstate->clientstate == CHAPCS_PENDING) {
      /* lower layer isn't up - wait until later */
      cstate->clientstate = CHAPCS_PENDING;
      return;
    }
  
    /*
     * We get here as a result of LCP coming up.
     * So even if CHAP was open before, we will 
     * have to re-authenticate ourselves.
     */
    cstate->clientstate = CHAPCS_LISTEN;
  }
  
  
  /*
   * ChapAuthPeer - Authenticate our peer (start server).
   */
  void
  ChapAuthPeer(int unit, char *our_name, int digest)
  {
    chap_state *cstate = &chap[unit];
  
    cstate->chal_name = our_name;
    cstate->chal_type = digest;
    
    if (cstate->serverstate == CHAPSS_INITIAL ||
        cstate->serverstate == CHAPSS_PENDING) {
      /* lower layer isn't up - wait until later */
      cstate->serverstate = CHAPSS_PENDING;
      return;
    }
  
    ChapGenChallenge(cstate);
    ChapSendChallenge(cstate);    /* crank it up dude! */
    cstate->serverstate = CHAPSS_INITIAL_CHAL;
  }
  
  
  /**********************************/
  /*** LOCAL FUNCTION DEFINITIONS ***/
  /**********************************/
  /*
   * ChapInit - Initialize a CHAP unit.
   */
  static void
  ChapInit(int unit)
  {
    chap_state *cstate = &chap[unit];
  
    BZERO(cstate, sizeof(*cstate));
    cstate->unit = unit;
    cstate->clientstate = CHAPCS_INITIAL;
    cstate->serverstate = CHAPSS_INITIAL;
    cstate->timeouttime = CHAP_DEFTIMEOUT;
    cstate->max_transmits = CHAP_DEFTRANSMITS;
    /* random number generator is initialized in magic_init */
  }
  
  
  /*
   * ChapChallengeTimeout - Timeout expired on sending challenge.
   */
  static void
  ChapChallengeTimeout(void *arg)
  {
    chap_state *cstate = (chap_state *) arg;
  
    /* if we aren't sending challenges, don't worry.  then again we */
    /* probably shouldn't be here either */
    if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
        cstate->serverstate != CHAPSS_RECHALLENGE) {
      return;
    }
  
    if (cstate->chal_transmits >= cstate->max_transmits) {
      /* give up on peer */
      CHAPDEBUG((LOG_ERR, "Peer failed to respond to CHAP challenge\n"));
      cstate->serverstate = CHAPSS_BADAUTH;
      auth_peer_fail(cstate->unit, PPP_CHAP);
      return;
    }
  
    ChapSendChallenge(cstate); /* Re-send challenge */
  }
  
  
  /*
   * ChapResponseTimeout - Timeout expired on sending response.
   */
  static void
  ChapResponseTimeout(void *arg)
  {
    chap_state *cstate = (chap_state *) arg;
  
    /* if we aren't sending a response, don't worry. */
    if (cstate->clientstate != CHAPCS_RESPONSE) {
      return;
    }
  
    ChapSendResponse(cstate);    /* re-send response */
  }
  
  
  /*
   * ChapRechallenge - Time to challenge the peer again.
   */
  static void
  ChapRechallenge(void *arg)
  {
    chap_state *cstate = (chap_state *) arg;
    
    /* if we aren't sending a response, don't worry. */
    if (cstate->serverstate != CHAPSS_OPEN) {
      return;
    }
  
    ChapGenChallenge(cstate);
    ChapSendChallenge(cstate);
    cstate->serverstate = CHAPSS_RECHALLENGE;
  }
  
  
  /*
   * ChapLowerUp - The lower layer is up.
   *
   * Start up if we have pending requests.
   */
  static void
  ChapLowerUp(int unit)
  {
    chap_state *cstate = &chap[unit];
  
    if (cstate->clientstate == CHAPCS_INITIAL) {
      cstate->clientstate = CHAPCS_CLOSED;
    } else if (cstate->clientstate == CHAPCS_PENDING) {
      cstate->clientstate = CHAPCS_LISTEN;
    }
  
    if (cstate->serverstate == CHAPSS_INITIAL) {
      cstate->serverstate = CHAPSS_CLOSED;
    } else if (cstate->serverstate == CHAPSS_PENDING) {
      ChapGenChallenge(cstate);
      ChapSendChallenge(cstate);
      cstate->serverstate = CHAPSS_INITIAL_CHAL;
    }
  }
  
  
  /*
   * ChapLowerDown - The lower layer is down.
   *
   * Cancel all timeouts.
   */
  static void
  ChapLowerDown(int unit)
  {
    chap_state *cstate = &chap[unit];
  
    /* Timeout(s) pending?  Cancel if so. */
    if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
        cstate->serverstate == CHAPSS_RECHALLENGE) {
      UNTIMEOUT(ChapChallengeTimeout, cstate);
    } else if (cstate->serverstate == CHAPSS_OPEN
        && cstate->chal_interval != 0) {
      UNTIMEOUT(ChapRechallenge, cstate);
    }
    if (cstate->clientstate == CHAPCS_RESPONSE) {
      UNTIMEOUT(ChapResponseTimeout, cstate);
    }
    cstate->clientstate = CHAPCS_INITIAL;
    cstate->serverstate = CHAPSS_INITIAL;
  }
  
  
  /*
   * ChapProtocolReject - Peer doesn't grok CHAP.
   */
  static void
  ChapProtocolReject(int unit)
  {
    chap_state *cstate = &chap[unit];
    
    if (cstate->serverstate != CHAPSS_INITIAL &&
        cstate->serverstate != CHAPSS_CLOSED) {
      auth_peer_fail(unit, PPP_CHAP);
    }
    if (cstate->clientstate != CHAPCS_INITIAL &&
        cstate->clientstate != CHAPCS_CLOSED) {
      auth_withpeer_fail(unit, PPP_CHAP);
    }
    ChapLowerDown(unit); /* shutdown chap */
  }
  
  
  /*
   * ChapInput - Input CHAP packet.
   */
  static void
  ChapInput(int unit, u_char *inpacket, int packet_len)
  {
    chap_state *cstate = &chap[unit];
    u_char *inp;
    u_char code, id;
    int len;
    
    /*
     * Parse header (code, id and length).
     * If packet too short, drop it.
     */
    inp = inpacket;
    if (packet_len < CHAP_HEADERLEN) {
      CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short header.\n"));
      return;
    }
    GETCHAR(code, inp);
    GETCHAR(id, inp);
    GETSHORT(len, inp);
    if (len < CHAP_HEADERLEN) {
      CHAPDEBUG((LOG_INFO, "ChapInput: rcvd illegal length.\n"));
      return;
    }
    if (len > packet_len) {
      CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short packet.\n"));
      return;
    }
    len -= CHAP_HEADERLEN;
    
    /*
     * Action depends on code (as in fact it usually does :-).
     */
    switch (code) {
      case CHAP_CHALLENGE:
        ChapReceiveChallenge(cstate, inp, id, len);
        break;
      
      case CHAP_RESPONSE:
        ChapReceiveResponse(cstate, inp, id, len);
        break;
      
      case CHAP_FAILURE:
        ChapReceiveFailure(cstate, inp, id, len);
        break;
      
      case CHAP_SUCCESS:
        ChapReceiveSuccess(cstate, inp, id, len);
        break;
      
      default:        /* Need code reject? */
        CHAPDEBUG((LOG_WARNING, "Unknown CHAP code (%d) received.\n", code));
        break;
    }
  }
  
  
  /*
   * ChapReceiveChallenge - Receive Challenge and send Response.
   */
  static void
  ChapReceiveChallenge(chap_state *cstate, u_char *inp, int id, int len)
  {
    int rchallenge_len;
    u_char *rchallenge;
    int secret_len;
    char secret[MAXSECRETLEN];
    char rhostname[256];
    MD5_CTX mdContext;
    u_char hash[MD5_SIGNATURE_SIZE];
    
    CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: Rcvd id %d.\n", id));
    if (cstate->clientstate == CHAPCS_CLOSED ||
      cstate->clientstate == CHAPCS_PENDING) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: in state %d\n",
           cstate->clientstate));
      return;
    }
  
    if (len < 2) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet.\n"));
      return;
    }
  
    GETCHAR(rchallenge_len, inp);
    len -= sizeof (u_char) + rchallenge_len;  /* now name field length */
    if (len < 0) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet.\n"));
      return;
    }
    rchallenge = inp;
    INCPTR(rchallenge_len, inp);
  
    if (len >= sizeof(rhostname)) {
      len = sizeof(rhostname) - 1;
    }
    BCOPY(inp, rhostname, len);
    rhostname[len] = '\000';
  
    CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: received name field '%s'\n", rhostname));
  
    /* Microsoft doesn't send their name back in the PPP packet */
    if (ppp_settings.remote_name[0] != 0 && (ppp_settings.explicit_remote || rhostname[0] == 0)) {
      strncpy(rhostname, ppp_settings.remote_name, sizeof(rhostname));
      rhostname[sizeof(rhostname) - 1] = 0;
      CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: using '%s' as remote name\n", rhostname));
    }
  
    /* get secret for authenticating ourselves with the specified host */
    if (!get_secret(cstate->unit, cstate->resp_name, rhostname, secret, &secret_len, 0)) {
      secret_len = 0;    /* assume null secret if can't find one */
      CHAPDEBUG((LOG_WARNING, "No CHAP secret found for authenticating us to %s\n", rhostname));
    }
  
    /* cancel response send timeout if necessary */
    if (cstate->clientstate == CHAPCS_RESPONSE) {
      UNTIMEOUT(ChapResponseTimeout, cstate);
    }
  
    cstate->resp_id = id;
    cstate->resp_transmits = 0;
  
    /*  generate MD based on negotiated type */
    switch (cstate->resp_type) { 
  
    case CHAP_DIGEST_MD5:
      MD5Init(&mdContext);
      MD5Update(&mdContext, &cstate->resp_id, 1);
      MD5Update(&mdContext, (u_char*)secret, secret_len);
      MD5Update(&mdContext, rchallenge, rchallenge_len);
      MD5Final(hash, &mdContext);
      BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE);
      cstate->resp_length = MD5_SIGNATURE_SIZE;
      break;
    
  #ifdef CHAPMS
    case CHAP_MICROSOFT:
      ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
      break;
  #endif
  
    default:
      CHAPDEBUG((LOG_INFO, "unknown digest type %d\n", cstate->resp_type));
      return;
    }
  
    BZERO(secret, sizeof(secret));
    ChapSendResponse(cstate);
  }
  
  
  /*
   * ChapReceiveResponse - Receive and process response.
   */
  static void
  ChapReceiveResponse(chap_state *cstate, u_char *inp, int id, int len)
  {
    u_char *remmd, remmd_len;
    int secret_len, old_state;
    int code;
    char rhostname[256];
    MD5_CTX mdContext;
    char secret[MAXSECRETLEN];
    u_char hash[MD5_SIGNATURE_SIZE];
    
    CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: Rcvd id %d.\n", id));
    
    if (cstate->serverstate == CHAPSS_CLOSED ||
        cstate->serverstate == CHAPSS_PENDING) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: in state %d\n",
      cstate->serverstate));
      return;
    }
  
    if (id != cstate->chal_id) {
      return;      /* doesn't match ID of last challenge */
    }
  
    /*
    * If we have received a duplicate or bogus Response,
    * we have to send the same answer (Success/Failure)
    * as we did for the first Response we saw.
    */
    if (cstate->serverstate == CHAPSS_OPEN) {
      ChapSendStatus(cstate, CHAP_SUCCESS);
      return;
    }
    if (cstate->serverstate == CHAPSS_BADAUTH) {
      ChapSendStatus(cstate, CHAP_FAILURE);
      return;
    }
    
    if (len < 2) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet.\n"));
      return;
    }
    GETCHAR(remmd_len, inp); /* get length of MD */
    remmd = inp;             /* get pointer to MD */
    INCPTR(remmd_len, inp);
    
    len -= sizeof (u_char) + remmd_len;
    if (len < 0) {
      CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet.\n"));
      return;
    }
  
    UNTIMEOUT(ChapChallengeTimeout, cstate);
    
    if (len >= sizeof(rhostname)) {
      len = sizeof(rhostname) - 1;
    }
    BCOPY(inp, rhostname, len);
    rhostname[len] = '\000';
  
    CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: received name field: %s\n", rhostname));
  
    /*
    * Get secret for authenticating them with us,
    * do the hash ourselves, and compare the result.
    */
    code = CHAP_FAILURE;
    if (!get_secret(cstate->unit, rhostname, cstate->chal_name, secret, &secret_len, 1)) {
      /* CHAPDEBUG((LOG_WARNING, TL_CHAP, "No CHAP secret found for authenticating %s\n", rhostname)); */
      CHAPDEBUG((LOG_WARNING, "No CHAP secret found for authenticating %s\n",
      rhostname));
    } else {
      /*  generate MD based on negotiated type */
      switch (cstate->chal_type) {
  
        case CHAP_DIGEST_MD5:    /* only MD5 is defined for now */
          if (remmd_len != MD5_SIGNATURE_SIZE) {
            break;      /* it's not even the right length */
          }
          MD5Init(&mdContext);
          MD5Update(&mdContext, &cstate->chal_id, 1);
          MD5Update(&mdContext, (u_char*)secret, secret_len);
          MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
          MD5Final(hash, &mdContext); 
          
          /* compare local and remote MDs and send the appropriate status */
          if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0) {
            code = CHAP_SUCCESS;  /* they are the same! */
          }
          break;
        
        default:
          CHAPDEBUG((LOG_INFO, "unknown digest type %d\n", cstate->chal_type));
      }
    }
    
    BZERO(secret, sizeof(secret));
    ChapSendStatus(cstate, code);
  
    if (code == CHAP_SUCCESS) {
      old_state = cstate->serverstate;
      cstate->serverstate = CHAPSS_OPEN;
      if (old_state == CHAPSS_INITIAL_CHAL) {
        auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
      }
      if (cstate->chal_interval != 0) {
        TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
      }
    } else {
      CHAPDEBUG((LOG_ERR, "CHAP peer authentication failed\n"));
      cstate->serverstate = CHAPSS_BADAUTH;
      auth_peer_fail(cstate->unit, PPP_CHAP);
    }
  }
  
  /*
   * ChapReceiveSuccess - Receive Success
   */
  static void
  ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len)
  {
    LWIP_UNUSED_ARG(id);
    LWIP_UNUSED_ARG(inp);
  
    CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: Rcvd id %d.\n", id));
  
    if (cstate->clientstate == CHAPCS_OPEN) {
      /* presumably an answer to a duplicate response */
      return;
    }
  
    if (cstate->clientstate != CHAPCS_RESPONSE) {
      /* don't know what this is */
      CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: in state %d\n", cstate->clientstate));
      return;
    }
    
    UNTIMEOUT(ChapResponseTimeout, cstate);
    
    /*
     * Print message.
     */
    if (len > 0) {
      PRINTMSG(inp, len);
    }
  
    cstate->clientstate = CHAPCS_OPEN;
  
    auth_withpeer_success(cstate->unit, PPP_CHAP);
  }
  
  
  /*
   * ChapReceiveFailure - Receive failure.
   */
  static void
  ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len)
  {
    LWIP_UNUSED_ARG(id);
    LWIP_UNUSED_ARG(inp);
  
    CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: Rcvd id %d.\n", id));
  
    if (cstate->clientstate != CHAPCS_RESPONSE) {
      /* don't know what this is */
      CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: in state %d\n", cstate->clientstate));
      return;
    }
  
    UNTIMEOUT(ChapResponseTimeout, cstate);
  
    /*
     * Print message.
     */
    if (len > 0) {
      PRINTMSG(inp, len);
    }
  
    CHAPDEBUG((LOG_ERR, "CHAP authentication failed\n"));
    auth_withpeer_fail(cstate->unit, PPP_CHAP);
  }
  
  
  /*
   * ChapSendChallenge - Send an Authenticate challenge.
   */
  static void
  ChapSendChallenge(chap_state *cstate)
  {
    u_char *outp;
    int chal_len, name_len;
    int outlen;
    
    chal_len = cstate->chal_len;
    name_len = strlen(cstate->chal_name);
    outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
    outp = outpacket_buf[cstate->unit];
    
    MAKEHEADER(outp, PPP_CHAP);    /* paste in a CHAP header */
    
    PUTCHAR(CHAP_CHALLENGE, outp);
    PUTCHAR(cstate->chal_id, outp);
    PUTSHORT(outlen, outp);
    
    PUTCHAR(chal_len, outp);    /* put length of challenge */
    BCOPY(cstate->challenge, outp, chal_len);
    INCPTR(chal_len, outp);
    
    BCOPY(cstate->chal_name, outp, name_len);  /* append hostname */
    
    pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
    
    CHAPDEBUG((LOG_INFO, "ChapSendChallenge: Sent id %d.\n", cstate->chal_id));
    
    TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime);
    ++cstate->chal_transmits;
  }
  
  
  /*
   * ChapSendStatus - Send a status response (ack or nak).
   */
  static void
  ChapSendStatus(chap_state *cstate, int code)
  {
    u_char *outp;
    int outlen, msglen;
    char msg[256];
    
    if (code == CHAP_SUCCESS) {
      strcpy(msg, "Welcome!");
    } else {
      strcpy(msg, "I don't like you.  Go 'way.");
    }
    msglen = strlen(msg);
    
    outlen = CHAP_HEADERLEN + msglen;
    outp = outpacket_buf[cstate->unit];
    
    MAKEHEADER(outp, PPP_CHAP);    /* paste in a header */
    
    PUTCHAR(code, outp);
    PUTCHAR(cstate->chal_id, outp);
    PUTSHORT(outlen, outp);
    BCOPY(msg, outp, msglen);
    pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
    
    CHAPDEBUG((LOG_INFO, "ChapSendStatus: Sent code %d, id %d.\n", code, cstate->chal_id));
  }
  
  /*
   * ChapGenChallenge is used to generate a pseudo-random challenge string of
   * a pseudo-random length between min_len and max_len.  The challenge
   * string and its length are stored in *cstate, and various other fields of
   * *cstate are initialized.
   */
  
  static void
  ChapGenChallenge(chap_state *cstate)
  {
    int chal_len;
    u_char *ptr = cstate->challenge;
    int i;
    
    /* pick a random challenge length between MIN_CHALLENGE_LENGTH and 
       MAX_CHALLENGE_LENGTH */  
    chal_len = (unsigned)
          ((((magic() >> 16) *
                (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) >> 16)
             + MIN_CHALLENGE_LENGTH);
    cstate->chal_len = chal_len;
    cstate->chal_id = ++cstate->id;
    cstate->chal_transmits = 0;
    
    /* generate a random string */
    for (i = 0; i < chal_len; i++ ) {
      *ptr++ = (char) (magic() & 0xff);
    }
  }
  
  /*
   * ChapSendResponse - send a response packet with values as specified
   * in *cstate.
   */
  /* ARGSUSED */
  static void
  ChapSendResponse(chap_state *cstate)
  {
    u_char *outp;
    int outlen, md_len, name_len;
    
    md_len = cstate->resp_length;
    name_len = strlen(cstate->resp_name);
    outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
    outp = outpacket_buf[cstate->unit];
    
    MAKEHEADER(outp, PPP_CHAP);
    
    PUTCHAR(CHAP_RESPONSE, outp);  /* we are a response */
    PUTCHAR(cstate->resp_id, outp);  /* copy id from challenge packet */
    PUTSHORT(outlen, outp);      /* packet length */
    
    PUTCHAR(md_len, outp);      /* length of MD */
    BCOPY(cstate->response, outp, md_len);    /* copy MD to buffer */
    INCPTR(md_len, outp);
    
    BCOPY(cstate->resp_name, outp, name_len);  /* append our name */
    
    /* send the packet */
    pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
    
    cstate->clientstate = CHAPCS_RESPONSE;
    TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime);
    ++cstate->resp_transmits;
  }
  
  #if 0
  static char *ChapCodenames[] = {
    "Challenge", "Response", "Success", "Failure"
  };
  /*
   * ChapPrintPkt - print the contents of a CHAP packet.
   */
  static int
  ChapPrintPkt( u_char *p, int plen, void (*printer) (void *, char *, ...), void *arg)
  {
    int code, id, len;
    int clen, nlen;
    u_char x;
    
    if (plen < CHAP_HEADERLEN) {
      return 0;
    }
    GETCHAR(code, p);
    GETCHAR(id, p);
    GETSHORT(len, p);
    if (len < CHAP_HEADERLEN || len > plen) {
      return 0;
    }
    if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *)) {
      printer(arg, " %s", ChapCodenames[code-1]);
    } else {
      printer(arg, " code=0x%x", code);
    }
    printer(arg, " id=0x%x", id);
    len -= CHAP_HEADERLEN;
    switch (code) {
      case CHAP_CHALLENGE:
      case CHAP_RESPONSE:
        if (len < 1) {
          break;
        }
        clen = p[0];
        if (len < clen + 1) {
          break;
        }
        ++p;
        nlen = len - clen - 1;
        printer(arg, " <");
        for (; clen > 0; --clen) {
          GETCHAR(x, p);
          printer(arg, "%.2x", x);
        }
        printer(arg, ">, name = %.*Z", nlen, p);
        break;
      case CHAP_FAILURE:
      case CHAP_SUCCESS:
        printer(arg, " %.*Z", len, p);
        break;
      default:
        for (clen = len; clen > 0; --clen) {
          GETCHAR(x, p);
          printer(arg, " %.2x", x);
        }
    }
  
    return len + CHAP_HEADERLEN;
  }
  #endif
  
  #endif /* CHAP_SUPPORT */
  
  #endif /* PPP_SUPPORT */
  