/* socklib.c
 * 
 * This module has all the socket stuff needed to get an
 * established connection.
 *
 * Basically the server side calls socket_declare() and
 * socket_accept().
 * The client side calls socket_connect()
 */

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#define TRUE 1
#define FALSE 0

static u_long squeeze_ip();
static int four_octets();

int socket_connect(char *hostname, int port) {
	struct sockaddr_in srvadr;
	struct hostent *hinfo;
	struct in_addr *haddr;
	char **address_list;
	int sockfd;

	memset(&srvadr, '\0', sizeof(srvadr));
	srvadr.sin_family = AF_INET;

	if (four_octets(hostname))
		srvadr.sin_addr.s_addr = squeeze_ip(hostname);
	else {
		hinfo = gethostbyname(hostname);
		if (hinfo == NULL)
			return (-1);
		address_list = hinfo->h_addr_list;
		haddr = (struct in_addr *) *address_list;
		srvadr.sin_addr.s_addr = haddr->s_addr;
}

srvadr.sin_port = htons(port);

if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	return(-1);

if (connect(sockfd, (struct sockaddr *) &srvadr, sizeof(srvadr)) == -1) {
	close(sockfd);
	return(-1);
}
return sockfd;
}

int socket_declare(int port) {
	struct sockaddr_in srvadr;
	int sockfd;

	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
			return(-1);
	memset(&srvadr, '\0', sizeof(srvadr));
	srvadr.sin_family = AF_INET;
	srvadr.sin_addr.s_addr = htonl(INADDR_ANY);
	srvadr.sin_port = htons(port);

	if (bind(sockfd, (struct sockaddr *) &srvadr, sizeof(srvadr)) == -1) {
		close(sockfd);
		return(-1);
	}

	if (listen(sockfd, 0) == -1) {
		close(sockfd);
		return(-1);
	}

	return sockfd;
}

int socket_accept(int insockfd) {
	int clisockfd;
	int clilen;
	struct sockaddr_in cliadr;

	clilen = sizeof(cliadr);
	clisockfd = accept(insockfd, (struct sockaddr *) &cliadr, &clilen);
	return clisockfd;
}

static u_long squeeze_ip(char *ipstr) {
	int ip1, ip2, ip3, ip4;
	union {
		u_char ichar[4];
		u_long ilong;
	} iunion;

	sscanf(ipstr, "%d.%d.%d.%d", &ip1, &ip2, &ip3, &ip4);
	iunion.ichar[0] = ip1;
	iunion.ichar[1] = ip2;
	iunion.ichar[2] = ip3;
	iunion.ichar[3] = ip4;
	return(iunion.ilong);
}

static int four_octets(char *hname) {
	int ans = TRUE;
	int i;

	for (i = 0; i < strlen(hname); ++i)
		if ((hname[i] < '0' || hname[i] > '9') && hname[i] != '.')
			ans = FALSE;
	return(ans);
}