xref: /csrg-svn/usr.bin/telnet/network.c (revision 32531)

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>

#include <errno.h>

#include <arpa/telnet.h>

#include "ring.h"

#include "defines.h"
#include "externs.h"

Ring	netoring, netiring;
char	netobuf[2*BUFSIZ], netibuf[BUFSIZ];

/*
 * Initialize internal network data structures.
 */

init_network()
{
    ring_init(&netoring, netobuf, sizeof netobuf);
    ring_init(&netiring, netibuf, sizeof netibuf);
    NetTrace = stdout;
}


/*
 * Check to see if any out-of-band data exists on a socket (for
 * Telnet "synch" processing).
 */

int
stilloob(s)
int	s;		/* socket number */
{
    static struct timeval timeout = { 0 };
    fd_set	excepts;
    int value;

    do {
	FD_ZERO(&excepts);
	FD_SET(s, &excepts);
	value = select(s+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
    } while ((value == -1) && (errno == EINTR));

    if (value < 0) {
	perror("select");
	quit();
    }
    if (FD_ISSET(s, &excepts)) {
	return 1;
    } else {
	return 0;
    }
}


/*
 *  setneturg()
 *
 *	Sets "neturg" to the current location.
 */

void
setneturg()
{
    ring_mark(&netoring);
}


/*
 *  netflush
 *		Send as much data as possible to the network,
 *	handling requests for urgent data.
 *
 *		The return value indicates whether we did any
 *	useful work.
 */


int
netflush()
{
    int n;

    if ((n = ring_full_consecutive(&netoring)) > 0) {
	if (!ring_at_mark(&netoring)) {
	    n = send(net, netoring.consume, n, 0);	/* normal write */
	} else {
	    /*
	     * In 4.2 (and 4.3) systems, there is some question about
	     * what byte in a sendOOB operation is the "OOB" data.
	     * To make ourselves compatible, we only send ONE byte
	     * out of band, the one WE THINK should be OOB (though
	     * we really have more the TCP philosophy of urgent data
	     * rather than the Unix philosophy of OOB data).
	     */
	    n = send(net, netoring.consume, 1, MSG_OOB);/* URGENT data */
	}
    }
    if (n < 0) {
	if (errno != ENOBUFS && errno != EWOULDBLOCK) {
	    setcommandmode();
	    perror(hostname);
	    NetClose(net);
	    ring_clear_mark(&netoring);
	    longjmp(peerdied, -1);
	    /*NOTREACHED*/
	}
	n = 0;
    }
    if (netdata && n) {
	Dump('>', netoring.consume, n);
    }
    ring_consumed(&netoring, n);
    return n > 0;
}

/*
 * 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 char *
nextitem(current)
char	*current;
{
    if ((*current&0xff) != IAC) {
	return current+1;
    }
    switch (*(current+1)&0xff) {
    case DO:
    case DONT:
    case WILL:
    case WONT:
	return current+3;
    case SB:		/* loop forever looking for the SE */
	{
	    register char *look = current+2;

	    for (;;) {
		if ((*look++&0xff) == IAC) {
		    if ((*look++&0xff) == SE) {
			return look;
		    }
		}
	    }
	}
    default:
	return current+2;
    }
}

/*
 * 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.
 */

void
netclear()
{
#if	0	/* XXX */
    register char *thisitem, *next;
    char *good;
#define	wewant(p)	((nfrontp > p) && ((*p&0xff) == IAC) && \
				((*(p+1)&0xff) != EC) && ((*(p+1)&0xff) != 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 */
    ring_init(&netoring, netobuf, sizeof netobuf);
}

#include <varargs.h>

void
netoprint(va_alist)
va_dcl
{
    va_list ap;
    char buffer[100];		/* where things go */
    char *ptr;
    char *format;
    char *string;
    int i;

    va_start(ap);

    format = va_arg(ap, char *);
    ptr = buffer;

    while ((i = *format++) != 0) {
	if (i == '%') {
	    i = *format++;
	    switch (i) {
	    case 'c':
		*ptr++ = va_arg(ap, int);
		break;
	    case 's':
		string = va_arg(ap, char *);
		ring_supply_data(&netoring, buffer, ptr-buffer);
		ring_supply_data(&netoring, string, strlen(string));
		ptr = buffer;
		break;
	    case 0:
		ExitString("netoprint: trailing %%.\n", 1);
		/*NOTREACHED*/
	    default:
		ExitString("netoprint: unknown format character.\n", 1);
		/*NOTREACHED*/
	    }
	} else {
	    *ptr++ = i;
	}
    }
    ring_supply_data(&netoring, buffer, ptr-buffer);
}