/**
 * @file icmp.h
 * @brief ICMP (Internet Control Message Protocol)
 *
 * @section License
 *
 * Copyright (C) 2021-2026 Oryx Embedded SARL. All rights reserved.
 *
 * This file is part of CycloneTCP Open
 * 
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * 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.

 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.6.4
 **/

#ifndef _ICMP_H
#define _ICMP_H

//Dependencies
#include "core/net.h"

//ICMP statistics support
#ifndef ICMP_STATS_SUPPORT
#if (MIB2_SUPPORT == ENABLED || IP_MIB_SUPPORT == ENABLED)
   #define ICMP_STATS_SUPPORT ENABLED
#else
   #define ICMP_STATS_SUPPORT DISABLED
#endif
#elif (ICMP_STATS_SUPPORT != ENABLED && ICMP_STATS_SUPPORT != DISABLED)
   #error ICMP_STATS_SUPPORT parameter is not valid
#endif

//ICMP query identifier range (lower limit)
#ifndef ICMP_QUERY_ID_MIN
   #define ICMP_QUERY_ID_MIN 0
#elif (ICMP_QUERY_ID_MIN < 0)
   #error ICMP_QUERY_ID_MIN parameter is not valid
#endif

//ICMP query identifier range (upper limit)
#ifndef ICMP_QUERY_ID_MAX
   #define ICMP_QUERY_ID_MAX 32767
#elif (ICMP_QUERY_ID_MAX <= ICMP_QUERY_ID_MIN || ICMP_QUERY_ID_MAX > 65535)
   #error ICMP_QUERY_ID_MAX parameter is not valid
#endif

//ICMP statistics
#if (ICMP_STATS_SUPPORT == ENABLED)
   #define ICMP_STATS_INC_COUNTER32(name, value) interface->netContext->icmpStats.name += value
#else
   #define ICMP_STATS_INC_COUNTER32(name, value)
#endif

//C++ guard
#ifdef __cplusplus
extern "C" {
#endif


/**
 * @brief ICMP message type
 *
 * The type field indicates the type of the message. Its
 * value determines the format of the remaining data
 *
 **/

typedef enum
{
   ICMP_TYPE_ECHO_REPLY          = 0,
   ICMP_TYPE_DEST_UNREACHABLE    = 3,
   ICMP_TYPE_SOURCE_QUENCH       = 4,
   ICMP_TYPE_REDIRECT            = 5,
   ICMP_TYPE_ALTERNATE_HOST_ADDR = 6,
   ICMP_TYPE_ECHO_REQUEST        = 8,
   ICMP_TYPE_ROUTER_ADV          = 9,
   ICMP_TYPE_ROUTER_SOL          = 10,
   ICMP_TYPE_TIME_EXCEEDED       = 11,
   ICMP_TYPE_PARAM_PROBLEM       = 12,
   ICMP_TYPE_TIMESTAMP_REQUEST   = 13,
   ICMP_TYPE_TIMESTAMP_REPLY     = 14,
   ICMP_TYPE_INFO_REQUEST        = 15,
   ICMP_TYPE_INFO_REPLY          = 16,
   ICMP_TYPE_ADDR_MASK_REQUEST   = 17,
   ICMP_TYPE_ADDR_MASK_REPLY     = 18,
   ICMP_TYPE_TRACEROUTE          = 30
} IcmpType;


/**
 * @brief Destination Unreachable message codes
 **/

typedef enum
{
   ICMP_CODE_NET_UNREACHABLE        = 0,
   ICMP_CODE_HOST_UNREACHABLE       = 1,
   ICMP_CODE_PROTOCOL_UNREACHABLE   = 2,
   ICMP_CODE_PORT_UNREACHABLE       = 3,
   ICMP_CODE_FRAG_NEEDED_AND_DF_SET = 4,
   ICMP_CODE_SOURCE_ROUTE_FAILED    = 5
} IcmpDestUnreachableCode;


/**
 * @brief Time Exceeded message codes
 **/

typedef enum
{
   ICMP_CODE_TTL_EXCEEDED             = 0,
   ICMP_CODE_REASSEMBLY_TIME_EXCEEDED = 1
} IcmpTimeExceededCode;


//CC-RX, CodeWarrior or Win32 compiler?
#if defined(__CCRX__)
   #pragma pack
#elif defined(__CWCC__) || defined(_WIN32)
   #pragma pack(push, 1)
#endif


/**
 * @brief ICMP header
 **/

typedef __packed_struct
{
   uint8_t type;      //0
   uint8_t code;      //1
   uint16_t checksum; //2-3
   uint8_t data[];    //4
} IcmpHeader;


/**
 * @brief ICMP Query message
 **/

typedef __packed_struct
{
   uint8_t type;        //0
   uint8_t code;        //1
   uint16_t checksum;   //2-3
   uint16_t identifier; //4-5
   uint16_t unused;     //6-7
   uint8_t data[];      //8
} IcmpQueryMessage;


/**
 * @brief ICMP Echo Request and Echo Reply messages
 **/

typedef __packed_struct
{
   uint8_t type;            //0
   uint8_t code;            //1
   uint16_t checksum;       //2-3
   uint16_t identifier;     //4-5
   uint16_t sequenceNumber; //6-7
   uint8_t data[];          //8
} IcmpEchoMessage;


/**
 * @brief ICMP Error message
 **/

typedef __packed_struct
{
   uint8_t type;      //0
   uint8_t code;      //1
   uint16_t checksum; //2-3
   uint8_t parameter; //4
   uint8_t unused[3]; //5-7
   uint8_t data[];    //8
} IcmpErrorMessage;


/**
 * @brief ICMP Destination Unreachable message
 **/

typedef __packed_struct
{
   uint8_t type;      //0
   uint8_t code;      //1
   uint16_t checksum; //2-3
   uint32_t unused;   //4-7
   uint8_t data[];    //8
} IcmpDestUnreachableMessage;


/**
 * @brief ICMP Time Exceeded message
 **/

typedef __packed_struct
{
   uint8_t type;      //0
   uint8_t code;      //1
   uint16_t checksum; //2-3
   uint32_t unused;   //4-7
   uint8_t data[];    //8
} IcmpTimeExceededMessage;


/**
 * @brief ICMP Parameter Problem message
 **/

typedef __packed_struct
{
   uint8_t type;      //0
   uint8_t code;      //1
   uint16_t checksum; //2-3
   uint8_t pointer;   //4
   uint8_t unused[3]; //5-7
   uint8_t data[];    //8
} IcmpParamProblemMessage;


//CC-RX, CodeWarrior or Win32 compiler?
#if defined(__CCRX__)
   #pragma unpack
#elif defined(__CWCC__) || defined(_WIN32)
   #pragma pack(pop)
#endif

//ICMP related functions
error_t icmpEnableEchoRequests(NetInterface *interface, bool_t enable);

error_t icmpEnableBroadcastEchoRequests(NetInterface *interface,
   bool_t enable);

void icmpProcessMessage(NetInterface *interface,
   const Ipv4PseudoHeader *requestPseudoHeader, const NetBuffer *buffer,
   size_t offset);

void icmpProcessEchoRequest(NetInterface *interface,
   const Ipv4PseudoHeader *requestPseudoHeader, const NetBuffer *request,
   size_t requestOffset);

error_t icmpSendErrorMessage(NetInterface *interface, uint8_t type,
   uint8_t code, uint8_t parameter, const NetBuffer *ipPacket,
   size_t ipPacketOffset);

void icmpDumpMessage(const IcmpHeader *message);
void icmpDumpEchoMessage(const IcmpEchoMessage *message);
void icmpDumpErrorMessage(const IcmpErrorMessage *message);

//C++ guard
#ifdef __cplusplus
}
#endif

#endif
