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#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <strings.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include "common.h"
static const unsigned char payload_response[] = {PAYLOAD_RESPONSE};
int main() {
unsigned char buffer[BUFSIZ];
int listenfd;
socklen_t len;
struct sockaddr_in servaddr = {};
struct sockaddr_in cliaddr;
listenfd = socket(AF_INET, SOCK_DGRAM, 0);
servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
servaddr.sin_port = htons(UDP_PORT);
servaddr.sin_family = AF_INET;
if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0) {
perror("udp bind");
return 1;
}
size_t i;
ssize_t n;
for (i = 0; i < MAX_UDP_PACKETS; ++i) {
len = sizeof(cliaddr);
n = recvfrom(listenfd, buffer, sizeof(buffer), 0,
(struct sockaddr *)&cliaddr, &len);
if (n < 0) {
perror("udp recvfrom");
break;
}
n = sendto(listenfd, payload_response, sizeof(payload_response), 0,
(struct sockaddr *)&cliaddr, sizeof(cliaddr));
if (n < 0) {
perror("udp sendto");
break;
}
}
close(listenfd);
return !(i == MAX_UDP_PACKETS);
}
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