/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 *	Copyright (c) 1988, 1989 Apple Computer, Inc. 
 *
 *   Modified, March 17, 1997 by Tuyen Nguyen for MacOSX.
 */

#ifndef lint
/* static char sccsid[] = "@(#)sip.c: 2.0, 1.3; 10/18/93; Copyright 1988-89, Apple Computer, Inc."; */
#endif  /* lint */

/****************************************************************/
/*								*/
/*								*/
/*				S I P				*/
/*			System Information Protocol		*/
/*								*/
/*								*/
/****************************************************************/

/* System Information Protocol -- implemented to handle Responder
 * Queries.  The queries are ATP requests, but the ATP responses are faked
 * here in a DDP level handler routine.  The responder socket is always
 * the 1st socket in the dynamic socket range (128) and it is assumed
 * that the node will be registered on that socket.
 * 
 * In A/UX implementation, this implies that /etc/appletalk program will
 * register the node name on socket DDP_SOCKET_1st_DYNAMIC (128).
 */

#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <machine/spl.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/fcntl.h>
#include <sys/mbuf.h>
#include <sys/ioctl.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

#include <net/if.h>

#include <netat/sysglue.h>  /* nbp.h needs the gbuf definiton */
#include <netat/appletalk.h>
#include <netat/ddp.h>
#include <netat/at_pcb.h>
#include <netat/at_var.h>
#include <netat/nbp.h>
#include <netat/atp.h>

#define	SIP_SYSINFO_CMD		1
#define	SIP_DATALINK_CMD	6

#define	SIP_GOOD_RESPONSE	0x1
#define	SIP_BAD_RESPONSE	0xff

#define	SIP_DRIVER_VERSION	0x0001
#define	SIP_RESPONDER_VERSION	0x0001

typedef	struct {
	u_char	response;
	u_char	unused;
	u_short	responder_version;
} sip_userbytes_t;

void sip_input(
     gbuf_t	*mp,
     __unused at_ifaddr_t	*ifID)
{
	/* Packets arriving here are actually ATP packets, but since
	 * A/UX only send dummy responses, we're implementing responder as
	 * a DDP handler
	 */
	register at_ddp_t	*ddp;
	register at_atp_t	*atp;
	register gbuf_t		*tmp;
	u_char		*resp;
	sip_userbytes_t	ubytes;

	ddp = (at_ddp_t *)gbuf_rptr(mp);

	/* Make sure the packet we got is an ATP packet */
	if (ddp->type != DDP_ATP) {
		gbuf_freem(mp);
		return;
	}
	
	/* assuming that the whole packet is in one contiguous buffer */
	atp = (at_atp_t	*)ddp->data;
	
	switch(UAL_VALUE_NTOH(atp->user_bytes)) {
	case SIP_SYSINFO_CMD :
		/* Sending a response with "AppleTalk driver version" (u_short)
		 * followed by 14 zeros will pacify the interpoll.
		 * What?  You don't understand what it means to send 14 zeroes?
		 * Tsk, tsk, look up SIP protocol specs for details!!
		 */
		if ((tmp = (gbuf_t *)ddp_growmsg(mp, 16)) == NULL) {
			/* dont have buffers */
			gbuf_freem(mp);
			return;
		}
		if (tmp == mp) 
			/* extra space allocated on the same buffer block */
			resp = atp->data;
		else
			resp = (u_char *)gbuf_rptr(tmp);
		bzero(resp, 16);
		*(u_short *)resp = htons(SIP_DRIVER_VERSION);

		ubytes.response = SIP_GOOD_RESPONSE;
		ubytes.unused = 0;
		ubytes.responder_version = htons(SIP_RESPONDER_VERSION);
		break;
	case SIP_DATALINK_CMD :
		/* In this case, the magic spell is to send 2 zeroes after
		 * the "AppleTalk driver version".
		 */
		if ((tmp = (gbuf_t *)ddp_growmsg(mp, 4)) == NULL) {
			/* dont have buffers */
			gbuf_freem(mp);
			return;
		}
		if (tmp == mp) 
			/* extra space allocated on the same buffer block */
			resp = atp->data;
		else
			resp = (u_char *)gbuf_rptr(tmp);
		bzero(resp, 16);
		*(u_short *)resp = htons(SIP_DRIVER_VERSION);

		ubytes.response = SIP_GOOD_RESPONSE;
		ubytes.unused = 0;
		ubytes.responder_version = htons(SIP_RESPONDER_VERSION);
		break;
	default :
		/* bad request, send a bad command response back */
		ubytes.response = SIP_BAD_RESPONSE;
		ubytes.unused = 0;
		ubytes.responder_version = htons(SIP_RESPONDER_VERSION);
	}

	NET_NET(ddp->dst_net, ddp->src_net);
	ddp->dst_node = ddp->src_node;
	ddp->dst_socket = ddp->src_socket;
	UAL_ASSIGN_HTON(atp->user_bytes, &ubytes);
	atp->cmd = ATP_CMD_TRESP;
	atp->eom = 1;
	atp->sts = 0;
	atp->bitmap = 0;

	(void)ddp_output(&mp, DDP_SOCKET_1st_DYNAMIC, FALSE);
	return;
} /* sip_input */