/*      $NetBSD: tcp_shutdown.c,v 1.1 2022/11/04 08:01:42 ozaki-r Exp $ */

/*-
* Copyright (c) 2022 Internet Initiative Japan Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
#ifdef __RCSID
__RCSID("$NetBSD: tcp_shutdown.c,v 1.1 2022/11/04 08:01:42 ozaki-r Exp $");
#else
extern const char *__progname;
#define getprogname() __progname
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

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

static inline bool
match(const char *a, const char *b)
{

       return strncmp(a, b, strlen(b)) == 0;
}

int
main(int argc, char *argv[])
{
       int s, e;
       char *target;

       if (argc != 2)
               errx(EXIT_FAILURE, "invalid argument");
       target = argv[1];

       s = socket(AF_INET, SOCK_STREAM, 0);
       if (s == -1)
               err(EXIT_FAILURE, "socket");
       e = shutdown(s, SHUT_RDWR);
       if (e == -1)
               err(EXIT_FAILURE, "shutdown");

       if (match(target, "connect")) {
               struct sockaddr_in sin;

               memset(&sin, 0, sizeof(sin));
               sin.sin_port = htons(31522);
               sin.sin_addr.s_addr = inet_addr("127.0.0.1");
               sin.sin_family = AF_INET;

               e = connect(s, (struct sockaddr *)&sin, sizeof(sin));
               if (e == 0)
                       err(EXIT_FAILURE, "connect didn't fail on a shudown socket");
               if (e == -1 && errno != EINVAL)
                       err(EXIT_FAILURE, "connect failed with unexpected error");
       } else if (match(target, "setsockopt")) {
               int opt = 1;
               e = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
               if (e == 0)
                       err(EXIT_FAILURE, "setsockopt didn't fail on a shutdown socket");
               if (e == -1 && errno != ECONNRESET)
                       err(EXIT_FAILURE, "setsockopt failed with unexpected error");
       } else if (match(target, "getsockname")) {
               struct sockaddr_storage ss;
               socklen_t len;
               e = getsockname(s, (struct sockaddr *)&ss, &len);
               if (e == 0)
                       err(EXIT_FAILURE, "getsockname didn't fail on a shutdown socket");
               if (e == -1 && errno != EINVAL)
                       err(EXIT_FAILURE, "getsockname failed with unexpected error");
       } else if (match(target, "listen")) {
               e = listen(s, 5);
               if (e == 0)
                       err(EXIT_FAILURE, "listen didn't fail on a shutdown socket");
               if (e == -1 && errno != EINVAL)
                       err(EXIT_FAILURE, "listen failed with unexpected error");
       } else if (match(target, "bind")) {
               struct sockaddr_in sin;

               memset(&sin, 0, sizeof(sin));
               sin.sin_port = htons(31522);
               sin.sin_addr.s_addr = inet_addr("127.0.0.1");
               sin.sin_family = AF_INET;

               e = bind(s, (struct sockaddr *)&sin, sizeof(sin));
               if (e == 0)
                       err(EXIT_FAILURE, "bind didn't fail on a shutdown socket");
               if (e == -1 && errno != EINVAL)
                       err(EXIT_FAILURE, "bind failed with unexpected error");
       } else if (match(target, "shutdown")) {
               e = shutdown(s, SHUT_RDWR);
               if (e == 0)
                       err(EXIT_FAILURE, "shutdown didn't fail on a shutdown socket");
               if (e == -1 && errno != EINVAL)
                       err(EXIT_FAILURE, "shutdown failed with unexpected error");
       } else {
               errx(EXIT_FAILURE, "unknown target: %s", target);
       }

       e = close(s);
       if (e == -1)
               err(EXIT_FAILURE, "close");
       return 0;
}