/*	$OpenBSD: socket.c,v 1.3 2004/02/06 11:33:22 henning Exp $	*/

/* BSD socket interface code... */

/*
 * Copyright (c) 1995, 1996, 1997, 1998, 1999
 * The Internet Software Consortium.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of The Internet Software Consortium nor the names
 *    of its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 */

#include "dhcpd.h"

/*
 * Generic interface registration routine...
 */
int
if_register_socket(struct interface_info *info)
{
	struct sockaddr_in name;
	int sock;
	int flag;

	/* Set up the address we're going to bind to. */
	memset(&name, 0, sizeof(name));
	name.sin_family = AF_INET;
	name.sin_port = local_port;
	name.sin_addr.s_addr = INADDR_ANY;

	/* Make a socket... */
	if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
		error("Can't create dhcp socket: %m");

	/* Set the REUSEADDR option so that we don't fail to start if
	   we're being restarted. */
	flag = 1;
	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
	    (char *)&flag, sizeof(flag)) < 0)
		error("Can't set SO_REUSEADDR option on dhcp socket: %m");

	flag = 1;
	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
	    (char *)&flag, sizeof(flag)) < 0)
		error("Can't set SO_REUSEPORT option on dhcp socket: %m");

	/* Set the BROADCAST option so that we can broadcast DHCP responses. */
	if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST,
	    (char *)&flag, sizeof(flag)) < 0)
		error("Can't set SO_BROADCAST option on dhcp socket: %m");

	/* Bind the socket to this interface's IP address. */
	if (bind(sock, (struct sockaddr *)&name, sizeof(name)) < 0)
		error("Can't bind to dhcp address: %m");

	flag = IPSEC_LEVEL_BYPASS;
	if (setsockopt(sock, IPPROTO_IP, IP_AUTH_LEVEL,
	    (char *)&flag, sizeof(flag)) == -1)
		if (errno != EOPNOTSUPP)
			error("Can't bypass auth IPsec on dhcp socket: %m");
	if (setsockopt(sock, IPPROTO_IP, IP_ESP_TRANS_LEVEL,
	    (char *)&flag, sizeof(flag)) == -1)
		if (errno != EOPNOTSUPP)
			error("Can't bypass ESP transport on dhcp socket: %m");
	if (setsockopt(sock, IPPROTO_IP, IP_ESP_NETWORK_LEVEL,
	    (char *)&flag, sizeof(flag)) == -1)
		if (errno != EOPNOTSUPP)
			error("Can't bypass ESP network on dhcp socket: %m");

	return (sock);
}

void
if_register_fallback(struct interface_info *info)
{
	info->wfdesc = if_register_socket(info);

	if (!quiet_interface_discovery)
		note("Sending on   Socket/%s%s%s",
		    info->name,
		    (info->shared_network ? "/" : ""),
		    (info->shared_network ?
		        info->shared_network -> name : ""));
}

ssize_t
send_fallback(struct interface_info *interface, struct packet *packet,
    struct dhcp_packet *raw, size_t len, struct in_addr from,
    struct sockaddr_in *to, struct hardware *hto)
{
	int result;

	result = sendto(interface->wfdesc, (char *)raw, len, 0,
	  (struct sockaddr *)to, sizeof(*to));

	if (result == -1) {
		warn("send_fallback: %m");
		if (errno == ENETUNREACH)
			warn("send_fallback: please consult README file %s",
			    "regarding broadcast address.");
	}
	return (result);
}

/*
 * This just reads in a packet and silently discards it.
 */
void
fallback_discard(struct protocol *protocol)
{
	char buf[1540];
	struct sockaddr_in from;
	socklen_t flen = sizeof(from);
	int status;
	struct interface_info *interface = protocol->local;

	status = recvfrom(interface->wfdesc, buf, sizeof(buf), 0,
	    (struct sockaddr *)&from, &flen);
	if (status == 0)
		warn("fallback_discard: %m");
}