4.3BSD - /usr/src/etc/timed/acksend.c

   1: /*
   2:  * Copyright (c) 1985 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)acksend.c	2.4 (Berkeley) 5/27/86";
   9: #endif not lint
  10: 
  11: #include "globals.h"
  12: #include <protocols/timed.h>
  13: 
  14: #define RECEIVED    0
  15: #define LOST        1
  16: #define SECFORACK   1   /* seconds */
  17: #define USECFORACK  0   /* microseconds */
  18: #define MAXCOUNT    5
  19: 
  20: struct tsp *answer;
  21: 
  22: /*
  23:  * Acksend implements reliable datagram transmission by using sequence
  24:  * numbers and retransmission when necessary.
  25:  * `name' is the name of the destination
  26:  * `addr' is the address to send to
  27:  * If `name' is ANYADDR, this routine implements reliable broadcast.
  28:  */
  29: 
  30: struct tsp *acksend(message, addr, name, ack, net)
  31: struct tsp *message;
  32: struct sockaddr_in *addr;
  33: char *name;
  34: int ack;
  35: struct netinfo *net;
  36: {
  37:     int count;
  38:     int flag;
  39:     extern u_short sequence;
  40:     struct timeval tout;
  41:     struct tsp *readmsg();
  42: 
  43:     count = 0;
  44: 
  45:     message->tsp_vers = TSPVERSION;
  46:     message->tsp_seq = sequence;
  47:     if (trace) {
  48:         fprintf(fd, "acksend: ");
  49:         if (name == ANYADDR)
  50:             fprintf(fd, "broadcast: ");
  51:         else
  52:             fprintf(fd, "%s: ", name);
  53:         print(message, addr);
  54:     }
  55:     bytenetorder(message);
  56:     do {
  57:         if (sendto(sock, (char *)message, sizeof(struct tsp), 0, addr,
  58:             sizeof(struct sockaddr_in)) < 0) {
  59:             syslog(LOG_ERR, "acksend: sendto: %m");
  60:             exit(1);
  61:         }
  62:         tout.tv_sec = SECFORACK;
  63:         tout.tv_usec = USECFORACK;
  64:         answer  = readmsg(ack, name, &tout, net);
  65:         if (answer != NULL) {
  66:             if (answer->tsp_seq != sequence) {
  67:                 if (trace)
  68:                     fprintf(fd, "acksend: seq # %d != %d\n",
  69:                         answer->tsp_seq, sequence);
  70:                 continue;
  71:             }
  72:             flag = RECEIVED;
  73:         } else {
  74:             flag = LOST;
  75:             if (++count == MAXCOUNT) {
  76:                 break;
  77:             }
  78:         }
  79:     } while (flag != RECEIVED);
  80:     sequence++;
  81:     return(answer);
  82: }

Defined functions

Defined variables

Defined macros