68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
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/*
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** talker.c -- a datagram "client" demo
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#define SERVERPORT "4711" // the port users will be connecting to
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int main(int argc, char *argv[])
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{
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int sockfd;
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struct addrinfo hints, *servinfo, *p;
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int rv;
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int numbytes;
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if (argc != 3) {
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fprintf(stderr,"usage: talker hostname message\n");
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exit(1);
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}
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memset(&hints, 0, sizeof hints);
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hints.ai_family = AF_UNSPEC;
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hints.ai_socktype = SOCK_DGRAM;
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if ((rv = getaddrinfo(argv[1], SERVERPORT, &hints, &servinfo)) != 0) {
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fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
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return 1;
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}
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// loop through all the results and make a socket
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for(p = servinfo; p != NULL; p = p->ai_next) {
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if ((sockfd = socket(p->ai_family, p->ai_socktype,
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p->ai_protocol)) == -1) {
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perror("talker: socket");
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continue;
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}
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break;
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}
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if (p == NULL) {
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fprintf(stderr, "talker: failed to bind socket\n");
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return 2;
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}
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if ((numbytes = sendto(sockfd, argv[2], strlen(argv[2]), 0,
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p->ai_addr, p->ai_addrlen)) == -1) {
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perror("talker: sendto");
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exit(1);
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}
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freeaddrinfo(servinfo);
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printf("talker: sent %d bytes to %s\n", numbytes, argv[1]);
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close(sockfd);
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return 0;
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}
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