/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  Utility functions for file transfer                                      *
*                                                                           *
*  Copyright 2008 Uli Meis <a.sporto+bee@gmail.com>                         *
*                                                                           *
*  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.,  *
*  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.              *
*                                                                           *
\***************************************************************************/

#define BITLBEE_CORE
#include "bitlbee.h"
#include <poll.h>
#include <netinet/tcp.h>
#include "lib/ftutil.h"

#define ASSERTSOCKOP(op, msg) \
	if( (op) == -1 ) {\
		g_snprintf( errmsg, sizeof( errmsg ), msg ": %s", strerror( errno ) ); \
		return -1; }

/*
 * Creates a listening socket and returns it in saddr_ptr.
 */
int ft_listen( struct sockaddr_storage *saddr_ptr, char *host, char *port, int copy_fd, int for_bitlbee_client, char **errptr )
{
	int fd, gret, saddrlen;
	struct addrinfo hints, *rp;
	socklen_t ssize = sizeof( struct sockaddr_storage );
	struct sockaddr_storage saddrs, *saddr = &saddrs;
	static char errmsg[1024];
	char *ftlisten = global.conf->ft_listen;

	if( errptr )
		*errptr = errmsg;

	strcpy( port, "0" );

	/* Format is <IP-A>[:<Port-A>];<IP-B>[:<Port-B>] where
	 * A is for connections with the bitlbee client (DCC)
	 * and B is for connections with IM peers.
	 */
	if( ftlisten )
	{
		char *scolon = strchr( ftlisten, ';' );
		char *colon;

		if( scolon )
		{
			if( for_bitlbee_client )
			{
				*scolon = '\0';
				strncpy( host, ftlisten, HOST_NAME_MAX );
				*scolon = ';';
			}
			else
			{
				strncpy( host, scolon + 1, HOST_NAME_MAX );
			}
		}
		else
		{
			strncpy( host, ftlisten, HOST_NAME_MAX );
		}

		if( ( colon = strchr( host, ':' ) ) )
		{
			*colon = '\0';
			strncpy( port, colon + 1, 5 );
		}
	}
	else if( copy_fd >= 0 && getsockname( copy_fd, (struct sockaddr*) &saddrs, &ssize ) == 0 &&
	         ( saddrs.ss_family == AF_INET || saddrs.ss_family == AF_INET6 ) &&
	         getnameinfo( (struct sockaddr*) &saddrs, ssize, host, HOST_NAME_MAX,
	                      NULL, 0, NI_NUMERICHOST ) == 0 )
	{
		/* We just took our local address on copy_fd, which is likely to be a
		   sensible address from which we can do a file transfer now - the
		   most sensible we can get easily. */
	}
	else
	{
		ASSERTSOCKOP( gethostname( host, HOST_NAME_MAX + 1 ), "gethostname()" );
	}

	memset( &hints, 0, sizeof( struct addrinfo ) );
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_NUMERICSERV;

	if ( ( gret = getaddrinfo( host, port, &hints, &rp ) ) != 0 )
	{
		sprintf( errmsg, "getaddrinfo() failed: %s", gai_strerror( gret ) );
		return -1;
	}

	saddrlen = rp->ai_addrlen;

	memcpy( saddr, rp->ai_addr, saddrlen );

	freeaddrinfo( rp );

	ASSERTSOCKOP( fd = socket( saddr->ss_family, SOCK_STREAM, 0 ), "Opening socket" );
	ASSERTSOCKOP( bind( fd, ( struct sockaddr *)saddr, saddrlen ), "Binding socket" );
	ASSERTSOCKOP( listen( fd, 1 ), "Making socket listen" );

	if ( !inet_ntop( saddr->ss_family, saddr->ss_family == AF_INET ?
			( void * )&( ( struct sockaddr_in * ) saddr )->sin_addr.s_addr :
			( void * )&( ( struct sockaddr_in6 * ) saddr )->sin6_addr.s6_addr,
			host, HOST_NAME_MAX ) )
	{
		strcpy( errmsg, "inet_ntop failed on listening socket" );
		return -1;
	}

	ssize = sizeof( struct sockaddr_storage );
	ASSERTSOCKOP( getsockname( fd, ( struct sockaddr *)saddr, &ssize ), "Getting socket name" );

	if( saddr->ss_family == AF_INET )
		g_snprintf( port, 6, "%d", ntohs( ( (struct sockaddr_in *) saddr )->sin_port ) );
	else
		g_snprintf( port, 6, "%d", ntohs( ( (struct sockaddr_in6 *) saddr )->sin6_port ) );

	if( saddr_ptr )
		memcpy( saddr_ptr, saddr, saddrlen );

	/* I hate static-length strings.. */
	host[HOST_NAME_MAX] = '\0';
	port[5] = '\0';
	
	return fd;
}