Listing 4. Example UDP Server
/*
* Listing 4:
* Example UDP (connectionless) server
* Ivan Griffin (ivan.griffin@ul.ie)
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/uio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#define MAX_MESG_SIZE 4096
char mesg[MAX_MESG_SIZE] = "";
int main(int argc, char *argv[])
{
int udpSocket = 0,
myPort = 0,
status = 0,
size = 0,
clientLength = 0;
struct sockaddr_in serverName = { 0 },
clientName = { 0 };
if (2 != argc)
{
fprintf(stderr, "Usage: %s <port>\n",
argv[0]);
exit(1);
}
myPort = atoi(argv[1]);
udpSocket = socket(PF_INET, SOCK_DGRAM,
IPPROTO_UDP);
if (-1 == udpSocket)
{
perror("socket()");
exit(1);
}
memset(&serverName, 0, sizeof(serverName));
memset(&clientName, 0, sizeof(clientName));
serverName.sin_family = AF_INET;
serverName.sin_addr.s_addr =
htonl(INADDR_ANY);
serverName.sin_port = htons(myPort);
status = bind(udpSocket, (struct sockaddr *)
&serverName, sizeof(serverName));
if (-1 == status)
{
perror("bind()");
exit(1);
}
for (;;)
{
size = recvfrom(udpSocket, mesg,
MAX_MESG_SIZE, 0,
(struct sockaddr *) &clientName,
&clientLength);
if (size == -1)
{
perror("recvfrom()");
exit(1);
}
status = sendto(udpSocket, mesg, size, 0,
(struct sockaddr *) &clientName,
clientLength);
if (status != size)
{
fprintf(stderr,
"sendto(): short write.\n");
exit(1);
}
}
/* never reached */
return 0;
}
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