1 /* $NetBSD: acksend.c,v 1.11 2007/01/26 16:12:41 christos 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
35 static char sccsid[] = "@(#)acksend.c 8.1 (Berkeley) 6/6/93";
36 #else
37 __RCSID("$NetBSD: acksend.c,v 1.11 2007/01/26 16:12:41 christos Exp $");
38 #endif
39 #endif /* not lint */
40
41 #include "globals.h"
42
43
44 struct tsp *answer;
45
46 extern u_short sequence;
47
48 void
xmit(int type,u_short seq,struct sockaddr_in * addr)49 xmit(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
62 int
sendtsp(int s,struct tsp * msg,struct sockaddr_in * addr)63 sendtsp(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 */
83 struct tsp *
acksend(struct tsp * message,struct sockaddr_in * addr,char * name,int ack,struct netinfo * net,int bad)84 acksend(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