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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "telnet_locl.h"
35 
36 RCSID("$Id: network.c 13941 2004-06-20 17:01:28Z lha $");
37 
38 Ring		netoring, netiring;
39 size_t		netobufsize = 64*1024;
40 size_t		netibufsize = 64*1024;
41 
42 /*
43  * Initialize internal network data structures.
44  */
45 
46 void
47 init_network(void)
48 {
49     void *obuf, *ibuf;
50 
51     if ((obuf = malloc(netobufsize)) == NULL)
52 	exit(1);
53     if ((ibuf = malloc(netibufsize)) == NULL)
54 	exit(1);
55 
56     if (ring_init(&netoring, obuf, netobufsize) != 1) {
57 	exit(1);
58     }
59     if (ring_init(&netiring, ibuf, netibufsize) != 1) {
60 	exit(1);
61     }
62     NetTrace = stdout;
63 }
64 
65 
66 /*
67  * Check to see if any out-of-band data exists on a socket (for
68  * Telnet "synch" processing).
69  */
70 
71 int
72 stilloob(void)
73 {
74     static struct timeval timeout = { 0 };
75     fd_set	excepts;
76     int value;
77 
78     do {
79 	FD_ZERO(&excepts);
80 	if (net >= FD_SETSIZE)
81 	    errx (1, "fd too large");
82 	FD_SET(net, &excepts);
83 	value = select(net+1, 0, 0, &excepts, &timeout);
84     } while ((value == -1) && (errno == EINTR));
85 
86     if (value < 0) {
87 	perror("select");
88 	quit();
89 	/* NOTREACHED */
90     }
91     if (FD_ISSET(net, &excepts)) {
92 	return 1;
93     } else {
94 	return 0;
95     }
96 }
97 
98 
99 /*
100  *  setneturg()
101  *
102  *	Sets "neturg" to the current location.
103  */
104 
105 void
106 setneturg(void)
107 {
108     ring_mark(&netoring);
109 }
110 
111 
112 /*
113  *  netflush
114  *		Send as much data as possible to the network,
115  *	handling requests for urgent data.
116  *
117  *		The return value indicates whether we did any
118  *	useful work.
119  */
120 
121 
122 int
123 netflush(void)
124 {
125     int n, n1;
126 
127 #if	defined(ENCRYPTION)
128     if (encrypt_output)
129 	ring_encrypt(&netoring, encrypt_output);
130 #endif
131     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
132 	if (!ring_at_mark(&netoring)) {
133 	    n = send(net, (char *)netoring.consume, n, 0); /* normal write */
134 	} else {
135 	    /*
136 	     * In 4.2 (and 4.3) systems, there is some question about
137 	     * what byte in a sendOOB operation is the "OOB" data.
138 	     * To make ourselves compatible, we only send ONE byte
139 	     * out of band, the one WE THINK should be OOB (though
140 	     * we really have more the TCP philosophy of urgent data
141 	     * rather than the Unix philosophy of OOB data).
142 	     */
143 	    n = send(net, (char *)netoring.consume, 1, MSG_OOB);/* URGENT data */
144 	}
145     }
146     if (n < 0) {
147 	if (errno != ENOBUFS && errno != EWOULDBLOCK) {
148 	    setcommandmode();
149 	    perror(hostname);
150 	    NetClose(net);
151 	    ring_clear_mark(&netoring);
152 	    longjmp(peerdied, -1);
153 	    /*NOTREACHED*/
154 	}
155 	n = 0;
156     }
157     if (netdata && n) {
158 	Dump('>', netoring.consume, n);
159     }
160     if (n) {
161 	ring_consumed(&netoring, n);
162 	/*
163 	 * If we sent all, and more to send, then recurse to pick
164 	 * up the other half.
165 	 */
166 	if ((n1 == n) && ring_full_consecutive(&netoring)) {
167 	    netflush();
168 	}
169 	return 1;
170     } else {
171 	return 0;
172     }
173 }
174