telnet.cc

这是关于远程登陆TELNET 的源代码 已经测试过的。

	  bol = 0;
	  ignore = 1;
	}
      } 
      if (!ignore) {
	int l;
	char buf[128];
	l = ttyiring.gets(buf, sizeof(buf));
	command(0, buf, l);
	bol = 1;
	flushline = 1;
	break;
      }
    } 
    else {
      bol = 0;
    }
#ifdef	KLUDGELINEMODE
    if (kludgelinemode && (globalmode&MODE_EDIT) && (sc == echoc)) {
      int ignore=0;
      if (ttyiring.getch(&c) > 0) {
	if (strip(c) != echoc) ttyiring.ungetch(c);
	else ignore=1;
      } 
      if (!ignore) {
	dontlecho = !dontlecho;
	settimer(echotoggle);
	setconnmode(0);
	flushline = 1;
	break;
      }
    }
#endif
    if (MODE_LOCAL_CHARS(globalmode)) {
      if (TerminalSpecialChars(sc) == 0) {
	bol = 1;
	break;
      }
    }
    if (my_want_state_is_wont(TELOPT_BINARY)) {
      switch (c) {
      case '\n':
	/*
	 * If we are in CRMOD mode (\r ==> \n)
	 * on our local machine, then probably
	 * a newline (unix) is CRLF (TELNET).
	 */
	if (MODE_LOCAL_CHARS(globalmode)) {
	  NETADD('\r');
	}
	NETADD('\n');
	bol = flushline = 1;
	break;
      case '\r':
	if (!crlf) {
	  NET2ADD('\r', '\0');
	} 
	else {
	  NET2ADD('\r', '\n');
	}
	bol = flushline = 1;
	break;
      case IAC:
	NET2ADD(IAC, IAC);
	break;
      default:
	NETADD(c);
	break;
      }
    } 
    else if (c == IAC) {
      NET2ADD(IAC, IAC);
    } 
    else {
      NETADD(c);
    }
  }
  
  return returnValue;		/* Non-zero if we did anything */
}

/*
 * Scheduler()
 *
 * Try to do something.
 *
 * If we do something useful, return 1; else return 0.
 *
 */

/* block: should we block in the select ? */
int Scheduler(int block) {
  /* One wants to be a bit careful about setting returnValue
   * to one, since a one implies we did some useful work,
   * and therefore probably won't be called to block next
   * time (TN3270 mode only).
   */
  int returnValue;
  int netin, netout, netex, ttyin, ttyout;
  
  /* Decide which rings should be processed */
  
  netout = netoring.full_count() &&
    (flushline ||
     (my_want_state_is_wont(TELOPT_LINEMODE)
#ifdef	KLUDGELINEMODE
      && (!kludgelinemode || my_want_state_is_do(TELOPT_SGA))
#endif
      ) ||
     my_want_state_is_will(TELOPT_BINARY));
  ttyout = ttyoring.full_count();
  
#if	defined(TN3270)
  ttyin = ttyiring.empty_count() && (shell_active == 0);
#else	/* defined(TN3270) */
  ttyin = ttyiring.empty_count();
#endif	/* defined(TN3270) */
  
#if defined(TN3270)
  netin = netiring.empty_count();
#else /* !defined(TN3270) */
  netin = !ISend && netiring.empty_count();
#endif /* !defined(TN3270) */
  
  netex = !SYNCHing;
  
  /* If we have seen a signal recently, reset things */
#ifdef TN3270
  if (HaveInput) {
    HaveInput = 0;
    (void) signal(SIGIO, inputAvailable);
  }
#endif	/* TN3270 */
  
  /* Call to system code to process rings */
  
  returnValue = process_rings(netin, netout, netex, ttyin, ttyout, !block);
  
  /* Now, look at the input rings, looking for work to do. */
  
  if (ttyiring.full_count()) {
#if defined(TN3270)
    if (In3270) {
      int c;
      
      c = DataFromTerminal(ttyiring.consume,
			   ring_full_consecutive(&ttyiring));
      if (c) {
	returnValue = 1;
	ring_consumed(&ttyiring, c);
      }
    } else {
#endif /* defined(TN3270) */
      returnValue |= telsnd();
#if defined(TN3270)
    }
#endif /* defined(TN3270) */
  }
  
  if (netiring.full_count()) {
#	if !defined(TN3270)
    returnValue |= telrcv();
#	else /* !defined(TN3270) */
    returnValue = Push3270();
#	endif /* !defined(TN3270) */
  }
  return returnValue;
}

/*
 * Select from tty and network...
 */
void telnet(const char * /*user*/) {
  sys_telnet_init();
  
  
#if !defined(TN3270)
  if (telnetport) {
    send_do(TELOPT_SGA, 1);
    send_will(TELOPT_TTYPE, 1);
    send_will(TELOPT_NAWS, 1);
    send_will(TELOPT_TSPEED, 1);
    send_will(TELOPT_LFLOW, 1);
    send_will(TELOPT_LINEMODE, 1);
    send_will(TELOPT_ENVIRON, 1);
    send_do(TELOPT_STATUS, 1);
    if (env_getvalue("DISPLAY", 0))
      send_will(TELOPT_XDISPLOC, 1);
    if (eight)
      tel_enter_binary(eight);
  }
#endif /* !defined(TN3270) */
  
#if !defined(TN3270)
  for (;;) {
    int schedValue;
    
    while ((schedValue = Scheduler(0)) != 0) {
      if (schedValue == -1) {
	setcommandmode();
	return;
      }
    }
    
    if (Scheduler(1) == -1) {
      setcommandmode();
      return;
    }
  }
#else /* !defined(TN3270) */
  for (;;) {
    int schedValue;
    
    while (!In3270 && !shell_active) {
      if (Scheduler(1) == -1) {
	setcommandmode();
	return;
      }
    }
    
    while ((schedValue = Scheduler(0)) != 0) {
      if (schedValue == -1) {
	setcommandmode();
	return;
      }
    }
    /* If there is data waiting to go out to terminal, don't
     * schedule any more data for the terminal.
     */
    if (ring_full_count(&ttyoring)) {
      schedValue = 1;
    } else {
      if (shell_active) {
	if (shell_continue() == 0) {
	  ConnectScreen();
	}
      } else if (In3270) {
	schedValue = DoTerminalOutput();
      }
    }
    if (schedValue && (shell_active == 0)) {
      if (Scheduler(1) == -1) {
	setcommandmode();
	return;
      }
    }
  }
#endif /* !defined(TN3270) */
}

#if	0	/* XXX - this not being in is a bug */
/*
 * nextitem()
 *
 *	Return the address of the next "item" in the TELNET data
 * stream.  This will be the address of the next character if
 * the current address is a user data character, or it will
 * be the address of the character following the TELNET command
 * if the current address is a TELNET IAC ("I Am a Command")
 * character.
 */

static unsigned char *nextitem(unsigned char *current) {
  if (*current != IAC) {
    return current+1;
  }
  switch (current[1]) {
  case DO:
  case DONT:
  case WILL:
  case WONT:
    return current+3;
  case SB:		/* loop forever looking for the SE */
    {
      unsigned char *look = current+2;
      
      for (;;) {
	if (*look++ == IAC) {
	  if (*look++ == SE) {
	    return look;
	  }
	}
      }
    }
  default:
    return current+2;
  }
}
#endif	/* 0 */

/*
 * netclear()
 *
 *	We are about to do a TELNET SYNCH operation.  Clear
 * the path to the network.
 *
 *	Things are a bit tricky since we may have sent the first
 * byte or so of a previous TELNET command into the network.
 * So, we have to scan the network buffer from the beginning
 * until we are up to where we want to be.
 *
 *	A side effect of what we do, just to keep things
 * simple, is to clear the urgent data pointer.  The principal
 * caller should be setting the urgent data pointer AFTER calling
 * us in any case.
 */

static void netclear(void) {
#if	0	/* XXX */
  register char *thisitem, *next;
  char *good;
#define	wewant(p)	((nfrontp > p) && (*p == IAC) && \
			 (p[1] != EC) && (p[1] != EL))
    
    thisitem = netobuf;
    
    while ((next = nextitem(thisitem)) <= netobuf.send) {
      thisitem = next;
    }
    
    /* Now, thisitem is first before/at boundary. */
    
    good = netobuf;	/* where the good bytes go */
    
    while (netoring.add > thisitem) {
      if (wewant(thisitem)) {
	int length;
	
	next = thisitem;
	do {
	  next = nextitem(next);
	} while (wewant(next) && (nfrontp > next));
	length = next-thisitem;
	memcpy(good, thisitem, length);
	good += length;
	thisitem = next;
      } else {
	thisitem = nextitem(thisitem);
      }
    }
    
#endif	/* 0 */
}

/*
 * These routines add various telnet commands to the data stream.
 */

static void doflush(void) {
  NET2ADD(IAC, DO);
  NETADD(TELOPT_TM);
  flushline = 1;
  flushout = 1;
  (void) ttyflush(1);			/* Flush/drop output */
  /* do printoption AFTER flush, otherwise the output gets tossed... */
  printoption("SENT", DO, TELOPT_TM);
}

void xmitAO(void) {
  NET2ADD(IAC, AO);
  printoption("SENT", IAC, AO);
  if (autoflush) {
    doflush();
  }
}


void xmitEL(void) {
  NET2ADD(IAC, EL);
  printoption("SENT", IAC, EL);
}

void xmitEC(void) {
  NET2ADD(IAC, EC);
  printoption("SENT", IAC, EC);
}


int dosynch(void) {
  netclear();			/* clear the path to the network */
  NETADD(IAC);
  netoring.set_mark();
  NETADD(DM);
  printoption("SENT", IAC, DM);
  return 1;
}

int want_status_response = 0;

int get_status(const char *, const char *) {
  unsigned char tmp[16];
  unsigned char *cp;
  
  if (my_want_state_is_dont(TELOPT_STATUS)) {
    printf("Remote side does not support STATUS option\n");
    return 0;
  }
  cp = tmp;
  
  *cp++ = IAC;
  *cp++ = SB;
  *cp++ = TELOPT_STATUS;
  *cp++ = TELQUAL_SEND;
  *cp++ = IAC;
  *cp++ = SE;
  printsub('>', tmp+2, cp - tmp - 2);
  netoring.write((char *)tmp, cp-tmp);
  ++want_status_response;
  return 1;
}

void intp(void) {
  NET2ADD(IAC, IP);
  printoption("SENT", IAC, IP);
  flushline = 1;
  if (autoflush) {
    doflush();
  }
  if (autosynch) {
    dosynch();
  }
}

void sendbrk(void) {
  NET2ADD(IAC, BREAK);
  printoption("SENT", IAC, BREAK);
  flushline = 1;
  if (autoflush) {
    doflush();
  }
  if (autosynch) {
    dosynch();
  }
}

void sendabort(void) {
  NET2ADD(IAC, ABORT);
  printoption("SENT", IAC, ABORT);
  flushline = 1;
  if (autoflush) {
    doflush();
  }
  if (autosynch) {
    dosynch();
  }
}

void sendsusp(void) {
  NET2ADD(IAC, SUSP);
  printoption("SENT", IAC, SUSP);
  flushline = 1;
  if (autoflush) {
    doflush();
  }
  if (autosynch) {
    dosynch();
  }
}

void sendeof(void) {
  NET2ADD(IAC, xEOF);
  printoption("SENT", IAC, xEOF);
}

void sendayt(void) {
  NET2ADD(IAC, AYT);
  printoption("SENT", IAC, AYT);
}

/*
 * Send a window size update to the remote system.
 */

void sendnaws(void) {
  long rows, cols;
  unsigned char tmp[16];
  unsigned char *cp;
  
  if (my_state_is_wont(TELOPT_NAWS))
    return;
  
#define	PUTSHORT(cp, x) { if ((*cp++ = ((x)>>8)&0xff) == IAC) *cp++ = IAC; \
      if ((*cp++ = ((x))&0xff) == IAC) *cp++ = IAC; }
  
  if (TerminalWindowSize(&rows, &cols) == 0) {	/* Failed */
    return;
  }
  
  cp = tmp;
  
  *cp++ = IAC;
  *cp++ = SB;
  *cp++ = TELOPT_NAWS;
  PUTSHORT(cp, cols);
  PUTSHORT(cp, rows);
  *cp++ = IAC;
  *cp++ = SE;
  printsub('>', tmp+2, cp - tmp - 2);
  netoring.write((char *)tmp, cp-tmp);
}

void tel_enter_binary(int rw) {
  if (rw&1)
    send_do(TELOPT_BINARY, 1);
  if (rw&2)
    send_will(TELOPT_BINARY, 1);
}

void tel_leave_binary(int rw) {
  if (rw&1)
    send_dont(TELOPT_BINARY, 1);
  if (rw&2)
    send_wont(TELOPT_BINARY, 1);
}