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Annotation of 43BSDTahoe/etc/timed/acksend.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1985 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that the above copyright notice and this paragraph are
                      7:  * duplicated in all such forms and that any documentation,
                      8:  * advertising materials, and other materials related to such
                      9:  * distribution and use acknowledge that the software was developed
                     10:  * by the University of California, Berkeley.  The name of the
                     11:  * University may not be used to endorse or promote products derived
                     12:  * from this software without specific prior written permission.
                     13:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     14:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     15:  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     16:  */
                     17: 
                     18: #ifndef lint
                     19: static char sccsid[] = "@(#)acksend.c  2.6 (Berkeley) 6/18/88";
                     20: #endif /* not lint */
                     21: 
                     22: #include "globals.h"
                     23: #include <protocols/timed.h>
                     24: 
                     25: #define RECEIVED       0
                     26: #define LOST           1
                     27: #define SECFORACK      1       /* seconds */
                     28: #define USECFORACK     0       /* microseconds */
                     29: #define MAXCOUNT       5
                     30: 
                     31: struct tsp *answer;
                     32: 
                     33: /*
                     34:  * Acksend implements reliable datagram transmission by using sequence 
                     35:  * numbers and retransmission when necessary.
                     36:  * `name' is the name of the destination
                     37:  * `addr' is the address to send to
                     38:  * If `name' is ANYADDR, this routine implements reliable broadcast.
                     39:  */
                     40: 
                     41: struct tsp *acksend(message, addr, name, ack, net)
                     42: struct tsp *message;
                     43: struct sockaddr_in *addr;
                     44: char *name;
                     45: int ack;
                     46: struct netinfo *net;
                     47: {
                     48:        int count;
                     49:        int flag;
                     50:        extern u_short sequence;
                     51:        struct timeval tout;
                     52:        struct tsp *readmsg();
                     53: 
                     54:        count = 0;
                     55: 
                     56:        message->tsp_vers = TSPVERSION;
                     57:        message->tsp_seq = sequence;
                     58:        if (trace) {
                     59:                fprintf(fd, "acksend: ");
                     60:                if (name == ANYADDR)
                     61:                        fprintf(fd, "broadcast: ");
                     62:                else
                     63:                        fprintf(fd, "%s: ", name);
                     64:                print(message, addr);
                     65:        }
                     66:        bytenetorder(message);
                     67:        do {
                     68:                if (sendto(sock, (char *)message, sizeof(struct tsp), 0, addr,
                     69:                    sizeof(struct sockaddr_in)) < 0) {
                     70:                        syslog(LOG_ERR, "acksend: sendto: %m");
                     71:                        exit(1);
                     72:                }
                     73:                tout.tv_sec = SECFORACK;
                     74:                tout.tv_usec = USECFORACK;
                     75:                answer  = readmsg(ack, name, &tout, net);
                     76:                if (answer != NULL) {
                     77:                        if (answer->tsp_seq != sequence) {
                     78:                                if (trace)
                     79:                                        fprintf(fd, "acksend: seq # %d != %d\n",
                     80:                                            answer->tsp_seq, sequence);
                     81:                                continue;
                     82:                        }
                     83:                        flag = RECEIVED;
                     84:                } else {
                     85:                        flag = LOST;
                     86:                        if (++count == MAXCOUNT) {
                     87:                                break;
                     88:                        }
                     89:                }
                     90:        } while (flag != RECEIVED);
                     91:        sequence++;
                     92:        return(answer);
                     93: }

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