Add a short regression test that triggers a TCP socket to enter time wait

while the socket is still open; one variant closes the socket while in
time wait, and a second lets time wait expire while the socket is open.

tools/regression/netinet/tcpsocktimewait/tcpsocktimewait.c

@@ -0,0 +1,169 @@
+/*-
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * TCP regression test that opens a loopback TCP session, then closes one end
+ * while shutting down the other.  This triggers an unusual TCP stack case in
+ * which an open file descriptor / socket is associated with a closed TCP
+ * connection.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+
+#include <err.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define	TCP_PORT	9001
+
+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");
+	}
+
+	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 secs)
+{
+	struct sockaddr_in sin;
+	int error, sock;
+
+	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");
+	}
+
+	if (shutdown(sock, SHUT_RDWR) < 0) {
+		error = errno;
+		(void)kill(partner, SIGKILL);
+		errno = error;
+		err(-1, "shutdown");
+	}
+
+	sleep(secs);
+	close(sock);
+}
+
+int
+main(int argc, char *argv[])
+{
+	pid_t child_pid, parent_pid;
+
+	if (signal(SIGCHLD, SIG_IGN) == SIG_ERR)
+		err(-1, "signal");
+
+	/*
+	 * Run the whole thing twice: once, with a short sleep in the client,
+	 * so that we close before time wait runs out, and once with a long
+	 * sleep so that the time wait terminates while the socket is open.
+	 */
+	parent_pid = getpid();
+	child_pid = fork();
+	if (child_pid < 0)
+		err(-1, "fork");
+	if (child_pid == 0) {
+		child_pid = getpid();
+		tcp_server(child_pid);
+	} else
+		tcp_client(parent_pid, 1);
+
+	parent_pid = getpid();
+	child_pid = fork();
+	if (child_pid < 0)
+		err(-1, "fork");
+	if (child_pid == 0) {
+		child_pid = getpid();
+		tcp_server(child_pid);
+	} else
+		tcp_client(parent_pid, 800);
+
+	return (0);
+}