1/*	$NetBSD: network.c,v 1.18 2018/12/14 23:40:17 christos Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)network.c	8.2 (Berkeley) 12/15/93";
36#else
37__RCSID("$NetBSD: network.c,v 1.18 2018/12/14 23:40:17 christos Exp $");
38#endif
39#endif /* not lint */
40
41#include <sys/types.h>
42#include <sys/socket.h>
43#include <sys/time.h>
44
45#include <errno.h>
46#include <unistd.h>
47#include <poll.h>
48
49#include <arpa/telnet.h>
50
51#include "ring.h"
52#include "defines.h"
53#include "externs.h"
54
55Ring		netoring, netiring;
56unsigned char	netobuf[2*BUFSIZ], netibuf[BUFSIZ];
57
58/*
59 * Initialize internal network data structures.
60 */
61
62void
63init_network(void)
64{
65    if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
66	exit(1);
67    }
68    if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
69	exit(1);
70    }
71    NetTrace = stdout;
72}
73
74
75/*
76 * Check to see if any out-of-band data exists on a socket (for
77 * Telnet "synch" processing).
78 */
79
80int
81stilloob(void)
82{
83    struct pollfd set[1];
84    int value;
85
86    set[0].fd = net;
87    set[0].events = POLLPRI;
88    do {
89	value = poll(set, 1, 0);
90    } while ((value == -1) && (errno == EINTR));
91
92    if (value < 0) {
93	perror("poll");
94	(void) quit(0, NULL);
95	/* NOTREACHED */
96    }
97    if (set[0].revents & POLLPRI) {
98	return 1;
99    } else {
100	return 0;
101    }
102}
103
104
105/*
106 *  setneturg()
107 *
108 *	Sets "neturg" to the current location.
109 */
110
111void
112setneturg(void)
113{
114    ring_mark(&netoring);
115}
116
117
118/*
119 *  netflush
120 *		Send as much data as possible to the network,
121 *	handling requests for urgent data.
122 *
123 *		The return value indicates whether we did any
124 *	useful work.
125 */
126
127
128int
129netflush(void)
130{
131    ssize_t n, n1;
132
133#ifdef	ENCRYPTION
134    if (encrypt_output)
135	ring_encrypt(&netoring, encrypt_output);
136#endif	/* ENCRYPTION */
137    if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
138	if (!ring_at_mark(&netoring)) {
139	    n = send(net, netoring.consume, (size_t)n, 0); /* normal write */
140	} else {
141	    /*
142	     * In 4.2 (and 4.3) systems, there is some question about
143	     * what byte in a sendOOB operation is the "OOB" data.
144	     * To make ourselves compatible, we only send ONE byte
145	     * out of band, the one WE THINK should be OOB (though
146	     * we really have more the TCP philosophy of urgent data
147	     * rather than the Unix philosophy of OOB data).
148	     */
149	    n = send(net, netoring.consume, 1, MSG_OOB);/* URGENT data */
150	}
151    }
152    if (n < 0) {
153	if (errno != ENOBUFS && errno != EWOULDBLOCK) {
154	    setcommandmode();
155	    perror(hostname);
156	    (void)NetClose(net);
157	    ring_clear_mark(&netoring);
158	    ExitString("Connection closed by foreign host.\n", 1);
159	    /*NOTREACHED*/
160	}
161	n = 0;
162    }
163    if (netdata && n) {
164	Dump('>', netoring.consume, (int)n);
165    }
166    if (n) {
167	ring_consumed(&netoring, (int)n);
168	/*
169	 * If we sent all, and more to send, then recurse to pick
170	 * up the other half.
171	 */
172	if ((n1 == n) && ring_full_consecutive(&netoring)) {
173	    (void) netflush();
174	}
175	return 1;
176    } else {
177	return 0;
178    }
179}
180