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