/*      $NetBSD: network.c,v 1.18 2018/12/14 23:40:17 christos Exp $    */

/*
* Copyright (c) 1988, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND 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 REGENTS OR 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.
*/

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)network.c   8.2 (Berkeley) 12/15/93";
#else
__RCSID("$NetBSD: network.c,v 1.18 2018/12/14 23:40:17 christos Exp $");
#endif
#endif /* not lint */

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

#include <errno.h>
#include <unistd.h>
#include <poll.h>

#include <arpa/telnet.h>

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

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

/*
* Initialize internal network data structures.
*/

void
init_network(void)
{
   if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
       exit(1);
   }
   if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
       exit(1);
   }
   NetTrace = stdout;
}


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

int
stilloob(void)
{
   struct pollfd set[1];
   int value;

   set[0].fd = net;
   set[0].events = POLLPRI;
   do {
       value = poll(set, 1, 0);
   } while ((value == -1) && (errno == EINTR));

   if (value < 0) {
       perror("poll");
       (void) quit(0, NULL);
       /* NOTREACHED */
   }
   if (set[0].revents & POLLPRI) {
       return 1;
   } else {
       return 0;
   }
}


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

void
setneturg(void)
{
   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(void)
{
   ssize_t n, n1;

#ifdef  ENCRYPTION
   if (encrypt_output)
       ring_encrypt(&netoring, encrypt_output);
#endif  /* ENCRYPTION */
   if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
       if (!ring_at_mark(&netoring)) {
           n = send(net, netoring.consume, (size_t)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);
           (void)NetClose(net);
           ring_clear_mark(&netoring);
           ExitString("Connection closed by foreign host.\n", 1);
           /*NOTREACHED*/
       }
       n = 0;
   }
   if (netdata && n) {
       Dump('>', netoring.consume, (int)n);
   }
   if (n) {
       ring_consumed(&netoring, (int)n);
       /*
        * If we sent all, and more to send, then recurse to pick
        * up the other half.
        */
       if ((n1 == n) && ring_full_consecutive(&netoring)) {
           (void) netflush();
       }
       return 1;
   } else {
       return 0;
   }
}