ICMP.h

/*
 * Copyright(c) Sophist Solutions, Inc. 1990-2025.  All rights reserved
 */
#ifndef _Stroika_Foundation_IO_Network_InternetProtocol_ICMP_h_
#define _Stroika_Foundation_IO_Network_InternetProtocol_ICMP_h_ 1
 
#include "Stroika/Foundation/StroikaPreComp.h"
 
#include <cstdint>
 
#include "Stroika/Foundation/Common/Common.h"
#include "Stroika/Foundation/Common/Endian.h"
#include "Stroika/Foundation/Execution/Exceptions.h"
#include "Stroika/Foundation/IO/Network/InternetAddress.h"
#include "Stroika/Foundation/Memory/Common.h"
 
/**
 *
 *  \note Code-Status:  <a href="Code-Status.md#Beta">Beta</a>
 *
 *
 * @see https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol
 *
 */
 
namespace Stroika::Foundation::IO::Network::InternetProtocol::ICMP {
 
    namespace V4 {
 
        /*
         *  ICMP packet types - from https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol "Control messages" 
         */
        enum class ICMP_PacketTypes : uint8_t {
            ICMP_ECHO_REPLY   = 0,
            ICMP_DEST_UNREACH = 3,
            ICMP_ECHO_REQUEST = 8,
            ICMP_TTL_EXPIRE   = 11,
        };
        using ICMP_PacketTypes::ICMP_DEST_UNREACH;
        using ICMP_PacketTypes::ICMP_ECHO_REPLY;
        using ICMP_PacketTypes::ICMP_ECHO_REQUEST;
        using ICMP_PacketTypes::ICMP_TTL_EXPIRE;
 
        /**
         * ICMP packet header (does not include IP header).
         *
         * @see https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol
         */
        Stroika_Foundation_Common_STRUCT_PACKED (struct PacketHeader {
            ICMP_PacketTypes type; // ICMP packet type
            uint8_t          code; // Type sub code
            uint16_t         checksum;
            uint16_t         id;
            uint16_t         seq;
            uint32_t         timestamp; // not part of ICMP, but we need it
        });
        static_assert (sizeof (PacketHeader) == 12, "Check Stroika_Foundation_Common_STRUCT_PACKED: ICMP::PacketHeader size wrong");
 
        // Minimum ICMP packet size, in bytes
        constexpr size_t ICMP_MIN{8};
 
        /**
         * @see https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol - Destination unreachable message
         */
        class DestinationUnreachableException : public Execution::RuntimeErrorException<> {
        private:
            using inherited = Execution::RuntimeErrorException<>;
 
        public:
            /**
             */
            DestinationUnreachableException (uint8_t code, const InternetAddress& unreachedIP);
 
        public:
            /**
            */
            nonvirtual uint8_t GetCode () const;
 
        public:
            nonvirtual InternetAddress GetUnreachedIP () const;
 
        private:
            uint8_t         fCode_;
            InternetAddress fUnreachedIP_;
        };
 
        /**
         */
        class UnknownICMPPacket : public Execution::RuntimeErrorException<> {
        private:
            using inherited = Execution::RuntimeErrorException<>;
 
        public:
            /**
             */
            UnknownICMPPacket (ICMP_PacketTypes type);
 
        public:
            /**
             */
            nonvirtual ICMP_PacketTypes GetType () const;
 
        private:
            ICMP_PacketTypes fType_;
        };
 
        /**
         *  @see https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol - means hop count (TTL) not large
         *  enough to reach destination
         *
         *  'ReachedIP' is the address reached by the packet when the TTL expired.
         */
        class TTLExpiredException : public Execution::RuntimeErrorException<> {
        private:
            using inherited = Execution::RuntimeErrorException<>;
 
        public:
            /**
             */
            TTLExpiredException (const InternetAddress& unreachedIP);
 
        public:
            nonvirtual InternetAddress GetUnreachedIP () const;
 
        private:
            InternetAddress fUnreachedIP_;
        };
    }
 
}
 
/*
 ********************************************************************************
 ***************************** Implementation Details ***************************
 ********************************************************************************
 */
#include "ICMP.inl"
 
#endif /*_Stroika_Foundation_IO_Network_InternetProtocol_ICMP_h_*/