/* This program accepts a single connection on PORT but it doesn't read
 * anything.  All the data piles up until the socket buffers are full.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <linux/sockios.h>


#define PORT 1111


int rd;


void stats()
{
	int len, err;
	int rcvbufsiz, used;

	len = sizeof(rcvbufsiz);
	err = getsockopt(rd, SOL_SOCKET, SO_RCVBUF, &rcvbufsiz, &len);
	if(err < 0) {
		perror("getsockopt");
		exit(1);
	}

	err = ioctl(rd, SIOCINQ, &used);
	if(err < 0) {
		perror("ioctl SIOCINQ");
		exit(1);
	}

	printf("Read buffer is %d bytes, with %d bytes used.\n",
			rcvbufsiz, used);
}


void sigint()
{
	stats();
	exit(0);
}


int main(int argc, char **argv)
{
	int sd, err;
	struct sockaddr_in addr;

	sd = socket(AF_INET, SOCK_STREAM, 0);
	if(sd<0) {
		perror("socket");
		exit(1);
	}

	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(PORT);

	err = bind(sd, (struct sockaddr*)&addr, sizeof(addr));
	if(err < 0) {
		perror("bind");
		exit(1);
	}

	err = listen(sd, 5);
	if(err < 0) {
		perror("listen");
		exit(1);
	}

	while(1) {
		printf("waiting on port %d...\n", PORT);

		rd = accept(sd, NULL, NULL);
		if(rd < 0) {
			perror("accept");
			exit(1);
		}

		stats();
		signal(SIGINT, sigint);

		for(;;) {
			sleep(100);
		}
	}
}