/* * Copyright (c) 1996 W. Richard Stevens. All rights reserved. * Permission to use or modify this software and its documentation only for * educational purposes and without fee is hereby granted, provided that * the above copyright notice appear in all copies. The author makes no * representations about the suitability of this software for any purpose. * It is provided "as is" without express or implied warranty. */ #include "cliserv.h" int main(int argc, char *argv[]) { struct sockaddr_in serv; char request[5000], reply[5000]; int sockfd, n, len, i; double rtt, minrtt; if (argc != 2) err_quit("usage: udpcli "); if ( (sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) err_sys("socket error"); memset(&serv, sizeof(serv), 0); serv.sin_family = AF_INET; serv.sin_addr.s_addr = inet_addr(argv[1]); serv.sin_port = htons(UDP_SERV_PORT); /* form request[] ... */ for (len = 0; len <= 1400; len += 100) { /* len = amount of user data */ printf("len = %d\n", len); minrtt = 9999999; for (i = 0; i < 30; i++) { start_timer(); if (sendto(sockfd, request, len, 0, (SA) &serv, sizeof(serv)) != len) err_sys("sendto error"); if ( (n = recvfrom(sockfd, reply, sizeof(reply), 0, (SA) NULL, (int *) NULL)) != len) err_sys("recvfrom error"); rtt = print_timer(); minrtt = min(minrtt, rtt); /* process "n" bytes of reply[] ... */ } printf("min rtt = %9.3f\n\n", minrtt); } exit(0); }