1 /* $NetBSD: acksend.c,v 1.6 2001/09/02 00:13:05 reinoud 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)acksend.c 8.1 (Berkeley) 6/6/93"; 40 #else 41 __RCSID("$NetBSD: acksend.c,v 1.6 2001/09/02 00:13:05 reinoud Exp $"); 42 #endif 43 #endif /* not lint */ 44 45 #include "globals.h" 46 47 48 struct tsp *answer; 49 50 extern u_short sequence; 51 52 void 53 xmit(int type, 54 u_short seq, 55 struct sockaddr_in *addr) 56 { 57 static struct tsp msg; 58 59 msg.tsp_type = type; 60 msg.tsp_seq = seq; 61 msg.tsp_vers = TSPVERSION; 62 (void)strcpy(msg.tsp_name, hostname); 63 bytenetorder(&msg); 64 if (sendto(sock, (char *)&msg, sizeof(struct tsp), 0, 65 (struct sockaddr*)addr, sizeof(struct sockaddr)) < 0) { 66 trace_sendto_err(addr->sin_addr); 67 } 68 } 69 70 71 /* 72 * Acksend implements reliable datagram transmission by using sequence 73 * numbers and retransmission when necessary. 74 * If `name' is ANYADDR, this routine implements reliable broadcast. 75 * 76 * Because this function calls readmsg(), none of its args may be in 77 * a message provided by readmsg(). 78 */ 79 struct tsp * 80 acksend(struct tsp *message, /* this message */ 81 struct sockaddr_in *addr, char *name, /* to here */ 82 int ack, /* look for this ack */ 83 struct netinfo *net, /* receive from this network */ 84 int bad) /* 1=losing patience */ 85 { 86 struct timeval twait; 87 int count; 88 long msec; 89 90 message->tsp_vers = TSPVERSION; 91 message->tsp_seq = sequence; 92 if (trace) { 93 fprintf(fd, "acksend: to %s: ", 94 (name == ANYADDR ? "broadcast" : name)); 95 print(message, addr); 96 } 97 bytenetorder(message); 98 99 msec = 200; 100 count = bad ? 1 : 5; /* 5 packets in 6.4 seconds */ 101 answer = 0; 102 do { 103 if (!answer) { 104 /* do not go crazy transmitting just because the 105 * other guy cannot keep our sequence numbers 106 * straight. 107 */ 108 if (sendto(sock, (char *)message, sizeof(struct tsp), 109 0, (struct sockaddr*)addr, 110 sizeof(struct sockaddr)) < 0) { 111 trace_sendto_err(addr->sin_addr); 112 break; 113 } 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