#include	<sys/types.h>	/* basic system data types */
#include	<sys/socket.h>	/* basic socket definitions */
#include	<sys/time.h>	/* timeval{} for select() */
#include	<time.h>		/* timespec{} for pselect() */
#include	<netinet/in.h>	/* sockaddr_in{} and other Internet defns */
#include	<arpa/inet.h>	/* inet(3) functions */
#include	<errno.h>
# include	<sys/select.h>	/* for select */
# include	<sys/stropts.h>	/* for INFTIM */
#include	<fcntl.h>		/* for nonblocking */
#include	<netdb.h>
#include	<signal.h>
#include	<stdio.h>
#include	<stdlib.h>
#include	<string.h>
# include	<strings.h>		/* for convenience */
#include	<limits.h>		/* for OPEN_MAX */
#include	<netinet/tcp.h>		/* for TCP_xxx defines */

union val {
  int			i_val;
  long		l_val;
  char		c_val[10];
  struct linger	linger_val;
  struct timeval	timeval_val;
} val;

static char	*sock_str_flag(union val *, int);
static char	*sock_str_int(union val *, int);
static char	*sock_str_linger(union val *, int);
static char	*sock_str_timeval(union val *, int);

struct sock_opts {
  char	   *opt_str;
  int		opt_level;
  int		opt_name;
  char   *(*opt_val_str)(union val *, int);
} sock_opts[] = {
	"SO_BROADCAST",		SOL_SOCKET,	SO_BROADCAST,	sock_str_flag,
	"SO_DEBUG",			SOL_SOCKET,	SO_DEBUG,		sock_str_flag,
	"SO_DONTROUTE",		SOL_SOCKET,	SO_DONTROUTE,	sock_str_flag,
	"SO_ERROR",			SOL_SOCKET,	SO_ERROR,		sock_str_int,
	"SO_KEEPALIVE",		SOL_SOCKET,	SO_KEEPALIVE,	sock_str_flag,
	"SO_LINGER",		SOL_SOCKET,	SO_LINGER,		sock_str_linger,
	"SO_OOBINLINE",		SOL_SOCKET,	SO_OOBINLINE,	sock_str_flag,
	"SO_RCVBUF",		SOL_SOCKET,	SO_RCVBUF,		sock_str_int,
	"SO_SNDBUF",		SOL_SOCKET,	SO_SNDBUF,		sock_str_int,
	"SO_RCVLOWAT",		SOL_SOCKET,	SO_RCVLOWAT,	sock_str_int,
	"SO_SNDLOWAT",		SOL_SOCKET,	SO_SNDLOWAT,	sock_str_int,
	"SO_RCVTIMEO",		SOL_SOCKET,	SO_RCVTIMEO,	sock_str_timeval,
	"SO_SNDTIMEO",		SOL_SOCKET,	SO_SNDTIMEO,	sock_str_timeval,
	"SO_REUSEADDR",		SOL_SOCKET,	SO_REUSEADDR,	sock_str_flag,
#ifdef	SO_REUSEPORT
	"SO_REUSEPORT",		SOL_SOCKET,	SO_REUSEPORT,	sock_str_flag,
#else
	"SO_REUSEPORT",		0,			0,				NULL,
#endif
	"SO_TYPE",			SOL_SOCKET,	SO_TYPE,		sock_str_int,
	/* "SO_USELOOPBACK",	SOL_SOCKET,	SO_USELOOPBACK,	sock_str_flag,  */
	"IP_TOS",			IPPROTO_IP,	IP_TOS,			sock_str_int,
	"IP_TTL",			IPPROTO_IP,	IP_TTL,			sock_str_int,
	"TCP_MAXSEG",		IPPROTO_TCP,TCP_MAXSEG,		sock_str_int,
	"TCP_NODELAY",		IPPROTO_TCP,TCP_NODELAY,	sock_str_flag,
	NULL,				0,			0,				NULL
};


int
main(int argc, char **argv)
{
	int					fd, len;
	struct sock_opts	*ptr;

	fd = socket(AF_INET, SOCK_STREAM, 0);
      if (fd < 0 )  {
         printf ("socket() failed, Err: %d \"%s\"\n",errno,strerror(errno));
         exit(1);
      }


	for (ptr = sock_opts; ptr->opt_str != NULL; ptr++) {
		printf("%s: ", ptr->opt_str);
		if (ptr->opt_val_str == NULL)
			printf("(undefined)\n");
		else {
			len = sizeof(val);
			if (getsockopt(fd, ptr->opt_level, ptr->opt_name,
						   &val, &len) == -1) {
                        printf ("getsockopt() failed, Err: %d \"%s\"\n",errno,strerror(errno));
			} else {
				printf("default = %s\n", (*ptr->opt_val_str)(&val, len));
			}
		}
	}
	exit(0);
}


static char	strres[128];

static char	*
sock_str_flag(union val *ptr, int len)
{
	if (len != sizeof(int))
		snprintf(strres, sizeof(strres), "size (%d) not sizeof(int)", len);
	else
		snprintf(strres, sizeof(strres),
				 "%s", (ptr->i_val == 0) ? "off" : "on");
	return(strres);
}

static char	*
sock_str_int(union val *ptr, int len)
{
	if (len != sizeof(int))
		snprintf(strres, sizeof(strres), "size (%d) not sizeof(int)", len);
	else
		snprintf(strres, sizeof(strres), "%d", ptr->i_val);
	return(strres);
}

static char	*
sock_str_linger(union val *ptr, int len)
{
	struct linger	*lptr = &ptr->linger_val;

	if (len != sizeof(struct linger))
		snprintf(strres, sizeof(strres),
				 "size (%d) not sizeof(struct linger)", len);
	else
		snprintf(strres, sizeof(strres), "l_onoff = %d, l_linger = %d",
				 lptr->l_onoff, lptr->l_linger);
	return(strres);
}

static char	*
sock_str_timeval(union val *ptr, int len)
{
	struct timeval	*tvptr = &ptr->timeval_val;

	if (len != sizeof(struct timeval))
		snprintf(strres, sizeof(strres),
				 "size (%d) not sizeof(struct timeval)", len);
	else
		snprintf(strres, sizeof(strres), "%d sec, %d usec",
				 tvptr->tv_sec, tvptr->tv_usec);
	return(strres);
}