/*
 * Copyright (c) 2007 - Andrey "nording" Chernyak <andrew@nording.ru>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Format and print Realtek Remote Control Protocol (RRCP), Realtek
 * Loop Detection Protocol (RLDP), and Realtek Echo Protocol (REP) packets,
 * as well as tag formats used by some Realtek switch chips to supply
 * tag information to a host CPU for a switch.
 */

/* \summary: printer for various Realtek protocols */

/*
 * See, for example, section 8.20 "Realtek Remote Control Protocol" of
 *
 *    http://realtek.info/pdf/rtl8324.pdf
 *
 * and section 7.22 "Realtek Remote Control Protocol" of
 *
 *    http://realtek.info/pdf/rtl8326.pdf
 *
 * and this page on the OpenRRCP Wiki:
 *
 *    http://openrrcp.org.ru/wiki/rrcp_protocol
 *
 * for information on RRCP.
 *
 * See, for example, section 8.21 "Network Loop Connection Fault
 * Detection" of
 *
 *    http://realtek.info/pdf/rtl8324.pdf
 *
 * and section 7.23 "Network Loop Connection Fault Detection" of
 *
 *    http://realtek.info/pdf/rtl8326.pdf
 *
 * for information on RLDP.
 *
 * See, for example, section 8.22 "Realtek Echo Protocol" of
 *
 *    http://realtek.info/pdf/rtl8324.pdf
 *
 * and section 7.24 "Realtek Echo Protocol" of
 *
 *    http://realtek.info/pdf/rtl8326.pdf
 *
 * for information on REP.
 *
 * NOTE: none of them indicate the byte order of multi-byte fields in any
 * obvious fashion.
 *
 * See section 8.10 "CPU Tag Function" of
 *
 *    http://realtek.info/pdf/rtl8306sd%28m%29_datasheet_1.1.pdf
 *
 * for the RTL8306 DSA protocol tag format.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"

#define RTL_FRAME_TYPE_OFFSET		0	/* frame type and other data - 1 byte */

/*
 * The upper 4 bits of the first octet of Realtek 0x8899 frames indicates
 * the frame type.
 */
#define RTL_FRAME_TYPE_MASK		0xF0
#define RTL_FRAME_TYPE_SUBTYPE		0x00	/* lower 4 bits are a subtype */
#define RTL_FRAME_TYPE_8306_DSA		0x90	/* RTL8306 DSA protocol */
#define RTL_FRAME_TYPE_8366RB_DSA	0xA0	/* RTL8366RB DSA protocol */
#define RTL_FRAME_TYPE_SHIFT		4

/*
 * The lower 4 bits are a subtype if the upper 4 bits are 0.
 */
#define RTL_FRAME_SUBTYPE_MASK		0x0F
#define RTL_FRAME_SUBTYPE_RRCP		0x01	/* RRCP */
#define RTL_FRAME_SUBTYPE_REP		0x02	/* REP */
#define RTL_FRAME_SUBTYPE_RLDP		0x03	/* RLDP */
#define RTL_FRAME_SUBTYPE_XXX_DSA	0x04	/* DSA protocol for some chip(s) */

#define RRCP_OPCODE_ISREPLY_OFFSET	1	/* opcode and isreply flag - 1 byte */

#define RRCP_OPCODE_MASK		0x7F	/* 0x00 = hello, 0x01 = get, 0x02 = set */
#define RRCP_ISREPLY			0x80	/* 0 = request to switch, 0x80 = reply from switch */

#define RRCP_OPCODE_HELLO		0x00
#define RRCP_OPCODE_GET_CONFIGURATION	0x01
#define RRCP_OPCODE_SET_CONFIGURATION	0x02

#define RRCP_AUTHKEY_OFFSET		2	/* authorization key - 2 bytes, 0x2379 by default */

/* most packets */
#define RRCP_REG_ADDR_OFFSET		4	/* register address - 2 bytes */
#define RRCP_REG_DATA_OFFSET		6	/* register data - 4 bytes */
#define RRCP_COOKIE1_OFFSET		10	/* 4 bytes */
#define RRCP_COOKIE2_OFFSET		14	/* 4 bytes */

/* hello reply packets */
#define RRCP_DOWNLINK_PORT_OFFSET	4	/* 1 byte */
#define RRCP_UPLINK_PORT_OFFSET		5	/* 1 byte */
#define RRCP_UPLINK_MAC_OFFSET		6	/* 6 byte MAC address */
#define RRCP_CHIP_ID_OFFSET		12	/* 2 bytes */
#define RRCP_VENDOR_ID_OFFSET		14	/* 4 bytes */

static const struct tok opcode_values[] = {
	{ RRCP_OPCODE_HELLO,             "hello" },
	{ RRCP_OPCODE_GET_CONFIGURATION, "get" },
	{ RRCP_OPCODE_SET_CONFIGURATION, "set" },
	{ 0, NULL }
};

/*
 * Print RRCP packets
 */
static void
rrcp_print(netdissect_options *ndo,
	  const u_char *cp)
{
	uint8_t rrcp_opcode;

	ndo->ndo_protocol = "rrcp";
	rrcp_opcode = GET_U_1((cp + RRCP_OPCODE_ISREPLY_OFFSET)) & RRCP_OPCODE_MASK;
	ND_PRINT("RRCP %s: %s",
		((GET_U_1(cp + RRCP_OPCODE_ISREPLY_OFFSET)) & RRCP_ISREPLY) ? "reply" : "query",
		tok2str(opcode_values,"unknown opcode (0x%02x)",rrcp_opcode));
	if (rrcp_opcode==RRCP_OPCODE_GET_CONFIGURATION ||
	    rrcp_opcode==RRCP_OPCODE_SET_CONFIGURATION){
    	    ND_PRINT(" addr=0x%04x, data=0x%08x",
		     GET_LE_U_2(cp + RRCP_REG_ADDR_OFFSET),
		     GET_LE_U_4(cp + RRCP_REG_DATA_OFFSET));
	}
	ND_PRINT(", auth=0x%04x",
	         GET_BE_U_2(cp + RRCP_AUTHKEY_OFFSET));
	if (rrcp_opcode==RRCP_OPCODE_HELLO &&
	     ((GET_U_1(cp + RRCP_OPCODE_ISREPLY_OFFSET)) & RRCP_ISREPLY)){
	    ND_PRINT(" downlink_port=%u, uplink_port=%u, uplink_mac=%s, vendor_id=%08x ,chip_id=%04x ",
		     GET_U_1(cp + RRCP_DOWNLINK_PORT_OFFSET),
		     GET_U_1(cp + RRCP_UPLINK_PORT_OFFSET),
		     GET_ETHERADDR_STRING(cp + RRCP_UPLINK_MAC_OFFSET),
		     GET_BE_U_4(cp + RRCP_VENDOR_ID_OFFSET),
		     GET_BE_U_2(cp + RRCP_CHIP_ID_OFFSET));
	}else if (rrcp_opcode==RRCP_OPCODE_GET_CONFIGURATION ||
	          rrcp_opcode==RRCP_OPCODE_SET_CONFIGURATION){
	    ND_PRINT(", cookie=0x%08x%08x ",
		    GET_BE_U_4(cp + RRCP_COOKIE2_OFFSET),
		    GET_BE_U_4(cp + RRCP_COOKIE1_OFFSET));
	}
}

/*
 * Print Realtek packets
 */
void
rtl_print(netdissect_options *ndo,
	  const u_char *cp,
	  u_int length _U_,
	  const struct lladdr_info *src,
	  const struct lladdr_info *dst)
{
	uint8_t rtl_proto;

	ndo->ndo_protocol = "rtl";

	if (src != NULL && dst != NULL) {
		ND_PRINT("%s > %s, ",
			(src->addr_string)(ndo, src->addr),
			(dst->addr_string)(ndo, dst->addr));
	}

	rtl_proto = GET_U_1(cp + RTL_FRAME_TYPE_OFFSET);

	switch (rtl_proto & RTL_FRAME_TYPE_MASK) {

	case RTL_FRAME_TYPE_SUBTYPE:
		/*
		 * Test the subtype.
		 */
		switch (rtl_proto & RTL_FRAME_SUBTYPE_MASK) {

		case RTL_FRAME_SUBTYPE_RRCP:
			rrcp_print(ndo, cp);
			break;

		case RTL_FRAME_SUBTYPE_REP:
			/*
			 * REP packets have no payload.
			 */
			ND_PRINT("REP");
			break;

		case RTL_FRAME_SUBTYPE_RLDP:
			/*
			 * RLDP packets have no payload.
			 */
			ND_PRINT("RLDP");
			break;

		case RTL_FRAME_SUBTYPE_XXX_DSA:
			ND_PRINT("Realtek 8-byte DSA tag");
			break;

		default:
			ND_PRINT("Realtek unknown subtype 0x%01x",
			    rtl_proto & RTL_FRAME_SUBTYPE_MASK);
			break;
		}
		break;

	case RTL_FRAME_TYPE_8306_DSA:
		ND_PRINT("Realtek RTL8306 4-byte DSA tag");
		break;

	case RTL_FRAME_TYPE_8366RB_DSA:
		ND_PRINT("Realtek RTL8366RB 4-byte DSA tag");
		break;

	default:
		ND_PRINT("Realtek unknown type 0x%01x",
		    (rtl_proto & RTL_FRAME_TYPE_MASK) >> RTL_FRAME_TYPE_SHIFT);
		break;
	}
}