#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdbool.h>

#define PIPE_RD 0
#define PIPE_WR 1

int
main(int argc, char **argv) {
	int sfd;
	struct sockaddr_in addr;
	int zfd;
	int pfd[2];
	size_t total = 0;

	if (argc != 4) {
		fprintf(stderr, "Usage: %s <addr> <port> <64k count>\n", argv[0]);
		exit(EXIT_FAILURE);
	}

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

	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(atoi(argv[2]));
	addr.sin_addr.s_addr = inet_addr(argv[1]);

	if (connect(sfd, &addr, sizeof(addr)) < 0) {
		perror("connect");
		exit(EXIT_FAILURE);
	}

	zfd = open("/dev/zero", O_RDONLY | O_CLOEXEC);
	if (zfd < 0) {
		perror("open");
		exit(EXIT_FAILURE);
	}

	if (pipe2(pfd, O_CLOEXEC) < 0) {
		perror("pipe2");
		exit(EXIT_FAILURE);
	}

	for (int i = 0; i < atoi(argv[3]); i++) {
		ssize_t r, w;

		r = splice(zfd, NULL, pfd[PIPE_WR], NULL, 64 * 1024, SPLICE_F_MOVE);
		//fprintf(stderr, "Read %zi bytes from /dev/zero\n", r);
		w = splice(pfd[PIPE_RD], NULL, sfd, NULL, r, SPLICE_F_MOVE);
		//fprintf(stderr, "Wrote %zi bytes to socket\n", w);
		if (r != w) {
			fprintf(stderr, "Read/write mismatch\n");
			exit(EXIT_FAILURE);
		}
		total += w;
	}

	printf("Client: sent %zu bytes\n", total);
	exit(EXIT_SUCCESS);
}