#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <ctype.h>
#include <netdb.h>
#include "get_tcp_conn.h"

extern int	errno;

/*
** Take the name of an internet host in ASCII (this may either be its
** official host name or internet number (with or without enclosing
** backets [])), and return the internet address number in 32 bit quantity.
**
** returns FAIL for failure to find the host name in the local database,
** or for a bad internet address spec.
*/
u_long
name_to_address(host)
register char	*host;
{
	if (host == (char *)NULL)
		return(FAIL);

	/*
	** Is this an ASCII internet address? (either of [10.0.0.78] or
	** 10.0.0.78).
	*/
	if (*host == '[' || isdigit(*host)) {
		u_long	host_address;
		char	namebuf[128];
		register char	*cp = namebuf;

		/*
		** strip brackets [] or anything else we don't want.
		*/
		while(*host && cp < &namebuf[sizeof(namebuf)]) {
			if (isdigit(*host) || *host == '.')
				*cp++ = *host++;
			else
				host++;
		}

		if ((host_address = inet_addr(namebuf)) == FAIL)
			return(FAIL);	/* malformed internet address spec */
		return(host_address);
	} else {
		struct hostent	*hstp = gethostbyname(host);

		if (hstp == NULL)
			return(FAIL);	/* no such host */
		return(*(u_long *)hstp->h_addr);	/* we assume... */
	}
}

/*
** given a host name (either name or internet address) and service name
** (or port number) (both in ASCII), give us a TCP connection to the
** requested service at the requested host (or give us FAIL).
*/
get_tcp_conn(host,serv)
char	*host;
char	*serv;
{
	u_short	port;
	struct in_addr	host_address;

	if ((host_address.s_addr = name_to_address(host)) == FAIL) {
		return(NOHOST);
	}

	if (isdigit(*serv)) {
		port = htons((u_short)(atoi(serv)));
	} else {
		struct servent	*srvp = getservbyname(serv, "tcp");

		if (srvp == NULL) {
			return(NOSERVICE);
		}
		port = (u_short)srvp->s_port;
	}

	return(mkconn(&host_address, port, IPPROTO_TCP, SOCK_STREAM));
}

/*
** create a socket and connect it to a remote host on the specified
** port by the specified protocol. Return FAIL if something goes
** wrong somewhere. Since these are exclusively system calls,
** errno will have the correct error in it.
*/
mkconn(host_address, port, protocol, proto_type)
struct in_addr	*host_address;
u_short	port;
int	protocol, proto_type;
{
	register int	skt;
	struct sockaddr_in	sadr;

	sadr.sin_family = (u_short)AF_INET;	/* Only internet for now */
	sadr.sin_addr.s_addr = host_address->s_addr;
	sadr.sin_port = (u_short)port;

	if ((skt = socket(AF_INET, proto_type, protocol)) < 0)
		return(FAIL);

	if (connect(skt, &sadr, sizeof(sadr)) < 0) {
		int	save = errno;

		close(skt);
		errno = save;
		return(FAIL);
	}
	return(skt);
}