72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
#include <stdio.h> /* standard C i/o facilities */
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#include <stdlib.h> /* needed for atoi() */
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#include <unistd.h> /* defines STDIN_FILENO, system calls,etc */
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#include <sys/types.h> /* system data type definitions */
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#include <sys/socket.h> /* socket specific definitions */
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#include <netinet/in.h> /* INET constants and stuff */
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#include <arpa/inet.h> /* IP address conversion stuff */
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#include <netdb.h> /* gethostbyname */
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/* this routine echos any messages (UDP datagrams) received */
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#define MAXBUF 1024*10
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void echo( int sd ) {
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int len,n;
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char bufin[MAXBUF];
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struct sockaddr_in remote;
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/* need to know how big address struct is, len must be set before the
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call to recvfrom!!! */
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len = sizeof(remote);
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long count = 0;
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while (1) {
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sleep(1);
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count++;
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n=recvfrom(sd,bufin,MAXBUF,0,(struct sockaddr *)&remote,&len);
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/* print out the address of the sender */
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printf("Got a datagram from %s port %d\n",
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inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));
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if (n<0) {
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perror("Error receiving data");
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} else {
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printf("GOT %d BYTES (count = %d)\n",n, count);
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sendto(sd,bufin,n,0,(struct sockaddr *)&remote,len);
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}
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}
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}
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int main() {
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int ld, length;
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struct sockaddr_in skaddr;
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if ((ld = socket( PF_INET, SOCK_DGRAM, 0 )) < 0) {
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printf("Problem creating socket\n");
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exit(1);
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}
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skaddr.sin_family = AF_INET;
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skaddr.sin_addr.s_addr = htonl(INADDR_ANY);
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skaddr.sin_port = htons(8888);
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if (bind(ld, (struct sockaddr *) &skaddr, sizeof(skaddr))<0) {
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printf("Problem binding\n");
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exit(0);
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}
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/*
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length = sizeof( skaddr );
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if (getsockname(ld, (struct sockaddr *) &skaddr, &length)<0) {
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printf("Error getsockname\n");
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exit(1);
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}
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*/
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printf("The server UDP port number is %d\n",ntohs(skaddr.sin_port));
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/* Go echo every datagram we get */
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echo(ld);
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return 0;
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}
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