/*  MasqMail
    Copyright (C) 1999 Oliver Kurth

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "masqmail.h"

static GList*
resolve_ip(GList * list, gchar * ip)
{
	struct in_addr ia;
	if (inet_aton(ip, &ia)) {
		mxip_addr mxip;

		mxip.name = g_strdup(ip);
		mxip.pref = 0;
		mxip.ip = (guint32) * (guint32 *) (&ia);
		list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
	}
	/* logwrite(LOG_ALERT, "invalid address '%s': inet_aton() failed\n", ip); */
	return NULL;
}

mxip_addr*
connect_hostlist(int *psockfd, gchar * host, guint port, GList * addr_list)
{
	GList *addr_node;
	struct sockaddr_in saddr;

	DEBUG(5) debugf("connect_hostlist entered\n");

	for (addr_node = g_list_first(addr_list); addr_node; addr_node = g_list_next(addr_node)) {
		mxip_addr *addr = (mxip_addr *) (addr_node->data);

		*psockfd = socket(PF_INET, SOCK_STREAM, 0);

		memset(&saddr, 0, sizeof(saddr));

		saddr.sin_family = AF_INET;
		saddr.sin_port = htons(port);

		/* clumsy, but makes compiler happy: */
		saddr.sin_addr = *(struct in_addr *) (&(addr->ip));
		DEBUG(5) debugf("  trying ip %s port %d\n", inet_ntoa(saddr.sin_addr), port);
		if (connect(*psockfd, (struct sockaddr *) (&saddr), sizeof(saddr)) == 0) {
			DEBUG(5) debugf("  connected to %s\n", inet_ntoa(saddr.sin_addr));
			return addr;
		} else {
			int saved_errno = errno;

			close(*psockfd);

			logwrite(LOG_WARNING, "connection to %s failed: %s\n", inet_ntoa(saddr.sin_addr), strerror(errno));

			errno = saved_errno;

			if ((saved_errno != ECONNREFUSED)
			    && (saved_errno != ETIMEDOUT)
			    && (saved_errno != ENETUNREACH)
			    && (saved_errno != EHOSTUNREACH))
				return NULL;
		}
	}
	return NULL;
}

/* Given a list of resolver functions, this function
   resolve the host and tries to connect to the addresses
   returned. If a connection attemp is timed out or refused,
   the next address is tried.

   TODO: the resolver functions might return duplicate addresses,
   if attempt failed for one it should not be tried again.
*/

mxip_addr*
connect_resolvelist(int *psockfd, gchar * host, guint port, GList * res_func_list)
{
	GList *res_node;
	GList *addr_list;

	DEBUG(5) debugf("connect_resolvelist entered\n");

	h_errno = 0;

	if (isdigit(host[0])) {
		mxip_addr *addr;

		addr_list = resolve_ip(NULL, host);
		if (addr_list) {
			addr = connect_hostlist(psockfd, host, port, addr_list);
			g_list_free(addr_list);
			return addr;
		}
		/* previous versions complained, until someone tried to use a hostname
		   out there that begins with a digit. eg. '3dwars.de'. */
	}

	if (res_func_list == NULL) {
		logwrite(LOG_ALERT, "res_funcs == NULL !!!\n");
		exit(EXIT_FAILURE);
	}

	foreach(res_func_list, res_node) {
		resolve_func res_func;
		DEBUG(6) debugf("  foreach() body\n");
		res_func = (resolve_func) (res_node->data);

		if (res_func == NULL) {
			logwrite(LOG_ALERT, "res_func == NULL !!!\n");
			exit(EXIT_FAILURE);
		}

		errno = 0;
		if ((addr_list = res_func(NULL, host))) {

			mxip_addr *addr;
			if ((addr = connect_hostlist(psockfd, host, port, addr_list)))
				return addr;

			DEBUG(5) {
				debugf("connect_hostlist failed: %s\n", strerror(errno));
			}

			g_list_free(addr_list);
		} else {
			if (!g_list_next(res_node)) {
				logwrite(LOG_ALERT, "could not resolve %s: %s\n", host, hstrerror(h_errno));
			}
		}
	}
	return NULL;

}