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app_04udp_server.c
57 lines (50 loc) · 1.41 KB
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app_04udp_server.c
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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define SIZE_BUF 200
int main(void)
{
unsigned short port = 9880;
struct sockaddr_in rcvAddr;
int sockfd, slen, rcvdLen;
char rcvBuf[SIZE_BUF];
int ret;
slen = sizeof(rcvAddr);
sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (sockfd == -1) {
exit(EXIT_FAILURE);
}
memset((char *) &rcvAddr, 0, sizeof(rcvAddr));
rcvAddr.sin_family = AF_INET;
rcvAddr.sin_port = htons(port);
rcvAddr.sin_addr.s_addr = htonl(INADDR_ANY);
bind(sockfd , (struct sockaddr*)&rcvAddr, sizeof(rcvAddr) );
while(1) {
fflush(stdout);
rcvdLen = recvfrom(sockfd, rcvBuf, SIZE_BUF, 0,
(struct sockaddr *) &rcvAddr, &slen);
if (rcvdLen == -1) {
close(sockfd);
exit(EXIT_FAILURE);
}
if (strstr(rcvBuf, "req") == NULL) { // accept only "req"
continue;
}
printf("rx: %s", rcvBuf);
// remove <LF>
if (rcvBuf[rcvdLen - 2] == '\n') {
rcvBuf[rcvdLen - 2] = 0x00;
}
strcat(rcvBuf, ",OK\n");
ret = sendto(sockfd, rcvBuf, strlen(rcvBuf)+1, 0,
(struct sockaddr*) &rcvAddr, slen);
if (ret == -1) {
close(sockfd);
exit(EXIT_FAILURE);
}
}
close(sockfd);
return 0;
}