/*-
 * Copyright (c) 2006 Robert N. M. Watson
 * Copyright (c) 2011 Juniper Networks, Inc.
 * All rights reserved.
 *
 * Portions of this software were developed by Robert N. M. Watson under
 * contract to Juniper Networks, Inc.
 *
 * 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 for the tcpdrop sysctl; build a loopback TCP
 * connection, drop it, and make sure both endpoints return that the
 * connection has been reset.
 */

#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>

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 listen_fd)
{
        int error, accept_fd;
        ssize_t len;
        char ch;

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

        /*
         * Send one byte, make sure that worked, wait for the drop, and try
         * sending another.  By sending small amounts, we avoid blocking
         * waiting on the remote buffer to be drained.
         */
        ch = 'A';
        len = send(accept_fd, &ch, sizeof(ch), MSG_NOSIGNAL);
        if (len < 0) {
                error = errno;
                (void)kill(partner, SIGTERM);
                errno = error;
                err(-1, "tcp_server: send (1)");
        }
        if (len != sizeof(ch)) {
                (void)kill(partner, SIGTERM);
                errx(-1, "tcp_server: send (1) len");
        }

        sleep (10);

        ch = 'A';
        len = send(accept_fd, &ch, sizeof(ch), MSG_NOSIGNAL);
        if (len >= 0) {
                (void)kill(partner, SIGTERM);
                errx(-1, "tcp_server: send (2): success");
        } else if (errno != EPIPE) {
                error = errno;
                (void)kill(partner, SIGTERM);
                errno = error;
                err(-1, "tcp_server: send (2)");
        }

        close(accept_fd);
        close(listen_fd);
}

static void
tcp_client(pid_t partner, u_short port)
{
        struct sockaddr_in sin, sin_local;
        int error, sock;
        socklen_t slen;
        ssize_t len;
        char ch;

        sleep(1);

        sock = socket(PF_INET, SOCK_STREAM, 0);
        if (sock < 0) {
                error = errno;
                (void)kill(partner, SIGTERM);
                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 = port;

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

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

        /*
         * Send one byte, make sure that worked, wait for the drop, and try
         * sending another.  By sending small amounts, we avoid blocking
         * waiting on the remote buffer to be drained.
         */
        ch = 'A';
        len = send(sock, &ch, sizeof(ch), MSG_NOSIGNAL);
        if (len < 0) {
                error = errno;
                (void)kill(partner, SIGTERM);
                errno = error;
                err(-1, "tcp_client: send (1)");
        }
        if (len != sizeof(ch)) {
                (void)kill(partner, SIGTERM);
                errx(-1, "tcp_client: send (1) len");
        }

        sleep(5);
        if (tcp_drop(&sin_local, &sin) < 0) {
                error = errno;
                (void)kill(partner, SIGTERM);
                errno = error;
                err(-1, "tcp_client: tcp_drop");
        }
        sleep(5);

        ch = 'A';
        len = send(sock, &ch, sizeof(ch), MSG_NOSIGNAL);
        if (len >= 0) {
                (void)kill(partner, SIGTERM);
                errx(-1, "tcp_client: send (2): success");
        } else if (errno != EPIPE) {
                error = errno;
                (void)kill(partner, SIGTERM);
                errno = error;
                err(-1, "tcp_client: send (2)");
        }
        close(sock);
}

int
main(int argc, char *argv[])
{
        pid_t child_pid, parent_pid;
        struct sockaddr_in sin;
        int listen_fd;
        u_short port;
        socklen_t len;

        listen_fd = socket(PF_INET, SOCK_STREAM, 0);
        if (listen_fd < 0)
                err(-1, "socket");

        /*
         * We use the loopback, but let the kernel select a port for the
         * server socket.
         */
        bzero(&sin, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_len = sizeof(sin);
        sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

        if (bind(listen_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0)
                err(-1, "bind");

        if (listen(listen_fd, -1) < 0)
                err(-1, "listen");

        /*
         * Query the port so that the client can use it.
         */
        bzero(&sin, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_len = sizeof(sin);
        len = sizeof(sin);
        if (getsockname(listen_fd, (struct sockaddr *)&sin, &len) < 0)
                err(-1, "getsockname");
        port = sin.sin_port;
        printf("Using port %d\n", ntohs(port));

        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, listen_fd);
        } else
                tcp_client(child_pid, port);

        return (0);
}