efax.c

用于使用moden进行传真的源代码

  return err ;
}


/* Log a sent/received HDLC frame.  Display of these messages is delayed to
   avoid possible timing problems. */

void logfr ( char *s , char *nm , uchar *p , int n )
{
  int i=0 ;
  msg ( n > 10 ? "H- %s %d bytes:" : "H-+ %s %d bytes:" , s, n ) ;
  for ( i=0 ; i<n ; i++ ) {
    msg ( "H-+  %02x" , p[i] & 0xff ) ;
    if ( ( i&0xf ) == 0xf && i != n-1 ) msg ( "H-" ) ;
  }
  msg ( "H-" ) ;
  msg ( "I- %s %s", s, nm ) ;
}


/* Send HDLC control frame of type type.  Extra bits can be OR'ed
   into the frame type (FCF) to indicate that this frame follows
   a previous one (no +FTH required) and/or that more frames will
   follow.  Sets up flag, address, and fax control field bytes in
   `buf'.  Sends these plus `len` additional bytes.  Terminates
   with DLE-ETX and checks response.  Returns 0 if OK, 2 or 3 on
   error. */

#define MORE_FR  0x100 
#define SUB_FR   0x200 

int nframes = 0 ;		/* counts frames sent/received */

int putframe ( int type, uchar *buf, int len, TFILE *f, int t )
{
  int err=0 ;

  buf [ 0 ] = 0xff ;
  buf [ 1 ] = type & MORE_FR ? 0xc0 : 0xc8 ;
  buf [ 2 ] = type & 0xff ;

  if ( nframes++ && ! ( type & SUB_FR ) )
    ckcmd ( f, &err, "+FTH=3" , TO_FT, CONNECT ) ;
  
  if ( ! err ) {

    if ( ! buf[len+2] ) {
      msg ( "Wlast byte of frame is NULL" ) ;
    }

    /* ttymode ( f, SEND ) ; */
    sendbuf ( f, buf, len+3, 0 ) ;
    tput ( f, DLE_ETX, 2 ) ; 
    /* ttymode ( f, COMMAND ) ; */

    logfr ( "sent", frname ( buf [ 2 ] ), buf, len+3 ) ;

    ckcmd ( f, &err, 0, TO_DRAIN_H, ( type & MORE_FR ) ? CONNECT : OK ) ;
  }

  return err ;
}


/* Reverse bit and byte order of ID strings as per T.30 5.3.6.2.4-6 */

void revcpy ( uchar *from , uchar *to )
{
  int i, j ;
  for ( i=0, j=IDLEN-1 ; i<IDLEN ; i++, j-- ) 
    to [ i ] = normalbits [ from [ j ] & 0xff ] ;
}


/* Check for missing initial 0xFF in HDLC frame and insert it if
   missing.  Ugly fix for a still-hidden bug.  Also do bit
   inversion if required. */

int fixframe ( uchar *buf, int n, TFILE *f )
{
  int i;

  if ( *buf == 0xc0 || *buf == 0xc8 ) {
    for ( i=n; i >= 1 ; i-- ) 
      buf[i]=buf[i-1] ;
    buf[i] = 0xff ;
    msg ("W HDLC frame missing initial 0xff" ) ;
    n++ ;
  }

  if ( buf[1] == 0x03 || buf[1] == 0x13 ) {
    for ( i=0 ; i < n ; i++ ) 
      buf[i]=normalbits[buf[i]] ;
    msg ("W bit-reversed HDLC frame, reversing bit order" ) ;
    f->ibitorder = f->ibitorder == normalbits ? reversebits : normalbits ;
  }

  return n ;
}


/* Read HDLC frame data.  Returns 0 if OK, 1 on frame error, 3 on
   timeout, invalid response or too-long frame. */

int receive_frame_data ( TFILE *f, uchar *buf, int n, int *len )
{
  int err=0, c, i ;

  for ( i=0 ; ( c = tgetd ( f, T3S ) ) >= 0  ; i++ )
    if ( i < n ) buf[ i ] = c ;
  
  if ( c == EOF ) {

    err = msg ( "E3timed out reading frame data" ) ;

  } else {
    
    switch ( cmd ( f, 0, TO_RTCMD ) ) {
    case OK:
    case CONNECT:
      break ;
    case ERROR:
    case NO:
      err = msg ( "W1frame error" ) ;
      break ;
    case EOF:
      err = msg ( "E3no response after frame data" ) ;
      break ;
    default:
      err = msg ( "E3wrong response after frame data" ) ;
      break ;
    }

  }

  if ( i >= n ) 
    err = msg ( "E3frame too long (%d, > %d max bytes)", i, n ) ;
  
  if ( len ) *len = i ;

  return err ;
}


/* Get a Class 1 command or response frame.  An attempt to match
   and combine T.30 "Response Received?" and "Command Received?"
   protocol flowcharts.

   When receiving commands returns after first correct
   non-optional frame or after the time given by getcmd has
   elapsed.  This is instead of looping through main flowchart.

   When receiving responses returns on the first detected
   non-optional frame, after timeout T4, or on errors.

   Returns immediately if gets a +FCERROR response so can retry
   as data carrier.  Returns DCN as a valid frame instead of
   hanging up.

   Returns the command/response received, or EOF on timeout or
   error.
 
*/

int getfr ( TFILE *mf, uchar *buf, int getcmd )
{
  int err=0, frame=0, frlen, c, t ;
  char remoteid [ IDLEN + 1 ] ;
  time_t start ;
  uchar *fif=buf+3 ;
  
  start = 10*time(0) ;
  
  t = getcmd ? ( getcmd > 1 ? getcmd : T2 ) : T4 ;

 Enter:

  err = 0 ;

  if ( nframes++ ) {
    c = cmd ( mf, "+FRH=3", t ) ;
  } else {
    c = CONNECT ;		/* implied by ATA or ATD */
  }
  
  switch ( c ) {
  case EOF:			/* time out */
    tput ( mf, CAN_STR, 1 ) ;
    ckcmd ( mf, 0, 0, TO_ABRT, OK ) ;
    err = 1 ;
    break ;
  case NO:			/* S7 time out */
    err = 1 ;
    break ;
  case MODULATION:		/* data carrier (or DHS) */
    return -msg ( "W-2 wrong carrier" ) ;
    break ;
  case CONNECT:			/* frame */
    break ;
  default:			/* shouldn't happen */
    err = msg ( "E3wrong response to receive-frame command" ) ;
    break ;
  }
  
  if ( ! err ) 
    err = receive_frame_data ( mf, buf, MAXFRLEN, &frlen ) ;
  
  if ( ! err && frlen < 3 ) 
    err = msg ( "E3received short frame (%d bytes)", frlen ) ;

  logfr ( "received", frname ( buf [ 2 ] ), buf, frlen ) ;

  if ( ! err ) {

    frlen = fixframe ( buf, frlen, mf ) ;
    frame = buf [ 2 ] & 0x7f ;

    switch ( frame ) {
    case CRP:
      err = 1 ;
    case NSF:
    case NSC:
    case NSS:
      goto Enter ;
    case CIG:
    case CSI:
    case TSI:
      revcpy ( fif , (uchar*) remoteid ) ;
      msg ( "I- remote ID -> %*.*s", IDLEN, IDLEN, remoteid ) ;
      goto Enter ;
    }

  }
  
  if ( err && getcmd && ( t -= 10*time(0) - start ) > 0 ) 
    goto Enter ;

  return err ? EOF : frame ;
}


/* Class 1 send/receive.  

  The logic in this function is a mess because it's meant to
  mirror the flowchart in ITU-T recommendation T.30 which is the
  protocol specification.

  */

int c1sndrcv ( 
	      TFILE *mf, cap local, char *localid, 
	      OFILE *outf, IFILE *inf, 
	      int pages, char *header, faxfont *font, 
	      int maxpgerr, int noretry, int calling )
{ 
  int err=0, rxpage=0, page=1, t, disbit, good, frame, last, nerr ;
  int rxdislen, ppm, try=0, pagetry=0, retry=0, remtx=0, remrx=0 ;
  int writepending=0, dp=0 ;
  cap remote = { DEFCAP }, session = { DEFCAP } ;
  char *fname=0 ;
  uchar buf [ MAXFRLEN ], *fif=buf+3 ;

  if ( ! calling ) goto RX ;

  /* Class 1 Transmitter: */

 T:  /* Transmitter Phase B - wait for DIS or DTC */

  pagetry = 0 ;
  
  frame = getfr ( mf, buf, T1 ) ;
  
  if ( frame <= 0 ) {
    err = msg ( "E3no answer from remote fax" ) ;
    goto B ;
  }
  
  if ( frame != DIS && frame != DTC ) {
    msg ( "W2 can't open page" ) ;
    goto C ;
  }

  disbit = ( frame == DIS ) ? 0x80 : 0x00 ;
  try = 0 ;

 A:				/* decide to send or receive after DIS/DTC */

  if ( frame == DIS || frame == DTC ) {
    rxdislen = dislen ( fif ) ;
    mkcap ( fif, remote, 1 ) ;
    remtx = fif[1] & 0x80 ;
    remrx = fif[1] & 0x40 ;
  }

  msg ( "N remote has %sdocument(s) to send, and can %sreceive",
       remtx ? "" : "no ", remrx ? "" : "not " ) ;

  if ( pages > 0 ) {
    if ( ! remrx ) msg ( "W remote cannot receive, trying anyways" ) ; 
    goto D ;
  } else {
    if ( ! remtx ) msg ( "W remote has nothing to send, trying anyways" )  ; 
    goto R ;
  }

 D:				/* send DCS */

  if ( rdpage ( inf, dp, &ppm, local, 0 ) ) {
    err = msg ( "E2can't open page" ) ;
    goto B ;
  }

 D_2:

  mincap ( local, remote, session ) ;

  revcpy ( (uchar*) localid, fif ) ;
  if ( ! err ) 
    err = putframe ( TSI | MORE_FR | disbit, buf, IDLEN, mf, -1 ) ;  

  mkdis ( session, fif, DCSLEN, 0, pages ) ;
  if ( ! err ) 
    err = putframe ( DCS | SUB_FR | disbit, buf, DCSLEN, mf, -1 ) ;

#ifdef USEFTS
  if ( cmd ( mf, "+FTS=" MODDLY, T3S ) != OK )
#endif
    msleep ( TMOD ) ;		/* if +FTS not supported */

  if ( ! err ) 
    err = puttrain ( mf, c1cmd[SND][TRN][session[BR]], 
		    TCFSECS*cps [ session[BR] ] ) ;
  try++ ;

  if ( ! err ) {
    cmd ( mf, "+FRS=1", T3S ) ; /* wait for TCF carrier to drop */
    frame = getfr ( mf, buf, 0 ) ;
  }

  if ( err || frame < 0 ) {
    if ( try >= 3 ) {
      goto C_timeout ;
    } else { 
      goto D_2 ;
    }
  }
  
  switch ( frame ) {

  case DIS:
  case DTC:
    if ( try >= 3 ) goto C_timeout ;
    else goto A ;

  case FTT:
    msg ( "I channel not usable at %d bps", 8*cps[session[BR]] ) ;
    remote[BR] = fallback[session[BR]] ;
    if ( remote[BR] >= 0 ) goto D_2 ;
    else { err = msg ( "E2 channel not usable at lowest speed" ) ; goto C ; }

  case CFR:
    goto I_2 ;

  default:
    err = msg ( "E3 invalid response to DCS (0x%02x)", frame ) ;
    goto C ;
  }    

 I:				/* send a page */

  if ( rdpage ( inf, dp, &ppm, local, 0 ) ) {
    err = msg ( "E2can't open page" ) ;
    goto B ;
  }

 I_2:

  ckcmd ( mf, &err, c1cmd [SND][DTA][session[BR]], TO_FT, CONNECT ) ;
  if ( !err ) {
    msleep ( 1000 ) ;
    err = send_data ( mf, inf, page, pages, local, session, header, font ) ;
  }

  pagetry++ ;

  if ( !err )
    err = end_data ( mf, session, 0, 0 ) ;
  
#ifdef USEFTS
  if ( cmd ( mf, "+FTS=" MODDLY, T3S ) != OK )
#endif
    msleep ( TMOD ) ;		/* if +FTS not supported */

				/* fix ppm if on last page of stdin */
  if ( lastpage ( inf ) ) ppm = EOP ;

  try = 0 ;
 sendppm:
  if ( !err ) err = putframe ( ppm | disbit, buf, 0, mf, -1 ) ;
  try++ ;
  
  frame = getfr ( mf, buf, 0 ) ;
  if ( frame < 0 ) {
    if ( try >= 3 ) {
      goto C_timeout ;
    } else { 
      goto sendppm ;
    }
  }

  fname = inf->page->fname ;

  switch ( noretry ? MCF : frame ) { /* common retry logic */
  case MCF:
  case RTP:
  case PIP:
    fname = inf->page->fname ;
    if ( fname ) msg ( "Isent -> %s", fname ) ;
    pagetry=0 ;
    page++ ;
    dp = 1 ;
    break ;
  case PIN:
  case RTN:
    dp = 0 ;
    retry = pagetry < NTXRETRY ;
    break ;
  default:  
    err = msg ( "E3invalid post-page response (0x%02x)", frame ) ;
    goto C ;
  }
  
  switch ( ppm ) {
    
  case MPS:
    switch ( frame ) {
    case PIN: goto E ;
    case PIP: goto E ;
    case MCF: goto I ;
    case RTP: goto D ;
    case RTN: goto D ;
    }

  case EOP:
    switch ( frame ) {
    case PIN: goto E ;
    case PIP: goto E ;
    case MCF: 
    case RTP: 
      nextipage ( inf, 1 ) ;	/* skip ahead to mark all files done */
      if ( remtx ) goto R ;	/* poll after sending */
      else goto C ;
    case RTN: 
      if ( retry ) goto D ;
      else goto C ;
    }
    
  case EOM:
    switch ( frame ) {
    case PIN: goto E ;
    case PIP: goto E ;
    case MCF: 
    case RTP: 
    case RTN: 
      cmd ( mf, "+FRS=20", T3S ) ; /* wait for ppr carrier to drop */
      if ( retry ) goto T ;
      else goto T ;
    }
    
  }  

 E:				/* ignore PIN and PIP */
  msg ( "W interrupt request ignored" ) ;
  try=0 ;
  goto A ;

  /* Class 1 Receiver */

 RX:

 R:  /* Receiver Phase B */