tcpsockclosebeforeaccept.c

/*-
 * Copyright (c) 2006 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * TCP regression test which opens a loopback TCP session, and closes it
 * before the remote endpoint (server) can accept it.  Run the test twice,
 * once using an explicit close() from the client, a second using a tcp drop.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>

#include <netinet/in.h>

#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define	TCP_PORT	9005

static int
tcp_drop(struct sockaddr_in *sin_local, struct sockaddr_in *sin_remote)
{
	struct sockaddr_storage addrs[2];

	/*
	 * Sysctl accepts an array of two sockaddr's, the first being the
	 * 'foreign' sockaddr, the second being the 'local' sockaddr.
	 */

	bcopy(sin_remote, &addrs[0], sizeof(*sin_remote));
	bcopy(sin_local, &addrs[1], sizeof(*sin_local));

	return (sysctlbyname("net.inet.tcp.drop", NULL, 0, addrs,
	    sizeof(addrs)));
}


static void
tcp_server(pid_t partner)
{
	int error, listen_fd, accept_fd;
	struct sockaddr_in sin;

	listen_fd = socket(PF_INET, SOCK_STREAM, 0);
	if (listen_fd < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "tcp_server: socket");
	}

	bzero(&sin, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_len = sizeof(sin);
	sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	sin.sin_port = htons(TCP_PORT);

	if (bind(listen_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "tcp_server: bind");
	}

	if (listen(listen_fd, -1) < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "tcp_server: listen");
	}

	sleep(10);

	accept_fd = accept(listen_fd, NULL, NULL);
	if (accept_fd < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "tcp_server: accept");
	}
	close(accept_fd);
	close(listen_fd);
}

static void
tcp_client(pid_t partner, int dropflag)
{
	struct sockaddr_in sin, sin_local;
	int error, sock;
	socklen_t slen;

	sleep(1);

	sock = socket(PF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "socket");
	}

	bzero(&sin, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_len = sizeof(sin);
	sin.sin_addr.s_addr = ntohl(INADDR_LOOPBACK);
	sin.sin_port = htons(TCP_PORT);

	if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "connect");
	}

	slen = sizeof(sin_local);
	if (getsockname(sock, (struct sockaddr *)&sin_local, &slen) < 0) {
		error = errno;
		(void)kill(partner, SIGKILL);
		errno = error;
		err(-1, "getsockname");
	}

	if (dropflag) {
		if (tcp_drop(&sin_local, &sin) < 0) {
			error = errno;
			(void)kill(partner, SIGKILL);
			errno = error;
			err(-1, "tcp_drop");
		}
		sleep(2);
	}
	close(sock);
}

int
main(int argc, char *argv[])
{
	pid_t child_pid, parent_pid;

	if (signal(SIGCHLD, SIG_IGN) == SIG_ERR)
		err(-1, "signal");

	parent_pid = getpid();
	child_pid = fork();
	if (child_pid < 0)
		err(-1, "fork");
	if (child_pid == 0) {
		child_pid = getpid();
		tcp_server(parent_pid);
		return (0);
	} else
		tcp_client(child_pid, 0);
	(void)kill(child_pid, SIGTERM);

	sleep(5);

	parent_pid = getpid();
	child_pid = fork();
	if (child_pid < 0)
		err(-1, "fork");
	if (child_pid == 0) {
		child_pid = getpid();
		tcp_server(parent_pid);
		return (0);
	} else
		tcp_client(child_pid, 1);
	(void)kill(child_pid, SIGTERM);

	return (0);
}