server.c

// Source: https://book.systemsapproach.org/foundation/software.html
// sudo lsof -i :5432

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>

#define SERVER_PORT  5432
#define MAX_PENDING  5

int main(int argc, const char *argv[])
{
	struct sockaddr_in sin;
	unsigned char buf[64];
	socklen_t addr_len;
	int s, new_s;
	size_t i;
	size_t n;
	size_t total_bytes_received = 0;
	size_t num_packets = 100000;
	int packets = 0;
	struct timeval start, end;
	unsigned long long elapsed;

	/* build address data structure */
	bzero((char *)&sin, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = INADDR_ANY;
	sin.sin_port = htons(SERVER_PORT);

	/* setup passive open */
	if ((s = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
		perror("socket failed");
		exit(1);
	}
	if ((bind(s, (struct sockaddr *)&sin, sizeof(sin))) < 0) {
		perror("bind failed");
		exit(1);
	}
	if (listen(s, MAX_PENDING) < 0) {
		perror("listen failed");
		exit(1);
	}

	if ((new_s = accept(s, (struct sockaddr *)&sin, &addr_len)) < 0) {
		perror("accept failed");
		exit(1);
	}

	gettimeofday(&start, NULL);

	do {
		n = recv(new_s, buf, sizeof(buf), 0);
		for (i = 0; i < n; i++) {
			if (buf[0] != 0x7f) {
				printf("data error\n");
				exit(0);
			}
		}
		packets++;
		if ((packets % 1000) == 0) {
			printf("completed %d packets\n", packets);
		}
		total_bytes_received += n;
	}
	while (n > 0);


	if (total_bytes_received != num_packets * 64) {
		printf("error: couldn't receive all packets\n");
		exit(0);
	}

	gettimeofday(&end, NULL);
	elapsed = (end.tv_sec * 1000000) + end.tv_usec - (start.tv_sec * 1000000) - start.tv_usec;

	printf("%d packets received in %lld milliseconds\n", packets, elapsed / 1000);

	close(new_s);
	close(s);
	return 0;
}