1/*	$NetBSD: acksend.c,v 1.10 2007/01/25 23:25:20 cbiere Exp $	*/
2
3/*-
4 * Copyright (c) 1985, 1993 The Regents of the University of California.
5 * 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[] = "@(#)acksend.c	8.1 (Berkeley) 6/6/93";
36#else
37__RCSID("$NetBSD: acksend.c,v 1.10 2007/01/25 23:25:20 cbiere Exp $");
38#endif
39#endif /* not lint */
40
41#include "globals.h"
42
43
44struct tsp *answer;
45
46extern u_short sequence;
47
48void
49xmit(int type, u_short seq, struct sockaddr_in *addr)
50{
51	static struct tsp msg;
52
53	msg.tsp_type = type;
54	msg.tsp_seq = seq;
55	msg.tsp_vers = TSPVERSION;
56
57	set_tsp_name(&msg, hostname);
58	bytenetorder(&msg);
59	(void)sendtsp(sock, &msg, addr);
60}
61
62int
63sendtsp(int s, struct tsp *msg, struct sockaddr_in *addr)
64{
65	int error;
66
67	error = sendto(s, msg, sizeof(*msg), 0,
68	    (struct sockaddr *)(void *)addr, sizeof(*addr));
69	if (error == -1)
70		trace_sendto_err(addr->sin_addr);
71	return error;
72}
73
74
75/*
76 * Acksend implements reliable datagram transmission by using sequence
77 * numbers and retransmission when necessary.
78 * If `name' is ANYADDR, this routine implements reliable broadcast.
79 *
80 * Because this function calls readmsg(), none of its args may be in
81 *	a message provided by readmsg().
82 */
83struct tsp *
84acksend(struct tsp *message,		/* this message */
85	struct sockaddr_in *addr, char *name,	/* to here */
86	int ack,			/* look for this ack */
87	struct netinfo *net,		/* receive from this network */
88	int bad)			/* 1=losing patience */
89{
90	struct timeval twait;
91	int count;
92	long msec;
93
94	message->tsp_vers = TSPVERSION;
95	message->tsp_seq = sequence;
96	if (trace) {
97		fprintf(fd, "acksend: to %s: ",
98			(name == ANYADDR ? "broadcast" : name));
99		print(message, addr);
100	}
101	bytenetorder(message);
102
103	msec = 200;
104	count = bad ? 1 : 5;	/* 5 packets in 6.4 seconds */
105	answer = 0;
106	do {
107		if (!answer) {
108			/* do not go crazy transmitting just because the
109			 * other guy cannot keep our sequence numbers
110			 * straight.
111			 */
112			if (sendtsp(sock, message, addr) == -1)
113				break;
114		}
115
116		mstotvround(&twait, msec);
117		answer  = readmsg(ack, name, &twait, net);
118		if (answer != 0) {
119			if (answer->tsp_seq != sequence) {
120				if (trace)
121					fprintf(fd,"acksend: seq # %u!=%u\n",
122						answer->tsp_seq, sequence);
123				continue;
124			}
125			break;
126		}
127
128		msec *= 2;
129	} while (--count > 0);
130	sequence++;
131
132	return(answer);
133}
134