ip_icmp.h

// Copyright 2021-2025 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
// Protocol handler for the Internet Control Message Protocol (ICMP)
 
#pragma once
 
#include <satcat5/net_core.h>
#include <satcat5/ip_core.h>
#include <satcat5/list.h>
#include <satcat5/polling.h>
 
namespace satcat5 {
    namespace ip {
        constexpr u16 ICMP_ECHO_REPLY           = 0x0000;
        constexpr u16 ICMP_UNREACHABLE_NET      = 0x0300;
        constexpr u16 ICMP_UNREACHABLE_HOST     = 0x0301;
        constexpr u16 ICMP_UNREACHABLE_PROTO    = 0x0302;
        constexpr u16 ICMP_UNREACHABLE_PORT     = 0x0303;
        constexpr u16 ICMP_FRAG_REQUIRED        = 0x0304;
        constexpr u16 ICMP_SRC_ROUTE_FAILED     = 0x0305;
        constexpr u16 ICMP_DST_NET_UNKNOWN      = 0x0306;
        constexpr u16 ICMP_DST_HOST_UNKNOWN     = 0x0307;
        constexpr u16 ICMP_SRC_HOST_ISOLATED    = 0x0308;
        constexpr u16 ICMP_NET_PROHIBITED       = 0x0309;
        constexpr u16 ICMP_HOST_PROHIBITED      = 0x030A;
        constexpr u16 ICMP_TOS_NET              = 0x030B;
        constexpr u16 ICMP_TOS_HOST             = 0x030C;
        constexpr u16 ICMP_COMM_PROHIBITED      = 0x030D;
        constexpr u16 ICMP_HOST_PRECEDENCE      = 0x030E;
        constexpr u16 ICMP_PRECEDENCE_CUTOFF    = 0x030F;
        constexpr u16 ICMP_REDIRECT_NET         = 0x0500;
        constexpr u16 ICMP_REDIRECT_HOST        = 0x0501;
        constexpr u16 ICMP_REDIRECT_NET_TOS     = 0x0502;
        constexpr u16 ICMP_REDIRECT_HOST_TOS    = 0x0503;
        constexpr u16 ICMP_ECHO_REQUEST         = 0x0800;
        constexpr u16 ICMP_TTL_EXPIRED          = 0x0B00;
        constexpr u16 ICMP_FRAG_TIMEOUT         = 0x0B01;
        constexpr u16 ICMP_IP_HDR_POINTER       = 0x0C00;
        constexpr u16 ICMP_IP_HDR_OPTION        = 0x0C01;
        constexpr u16 ICMP_IP_HDR_LENGTH        = 0x0C02;
        constexpr u16 ICMP_TIME_REQUEST         = 0x0D00;
        constexpr u16 ICMP_TIME_REPLY           = 0x0E00;
 
        constexpr u16 ICMP_TYPE_MASK            = 0xFF00;
        constexpr u16 ICMP_TYPE_UNREACHABLE     = 0x0300;   // 0x0300 - 03FF
        constexpr u16 ICMP_TYPE_REDIRECT        = 0x0500;   // 0x0500 - 05FF
        constexpr u16 ICMP_TYPE_TIME_EXCEED     = 0x0B00;   // 0x0B00 - 0BFF
        constexpr u16 ICMP_TYPE_BAD_IP_HDR      = 0x0C00;   // 0x0C00 - 0CFF
 
        constexpr unsigned ICMP_ECHO_BYTES   = 8;
 
        class PingListener {
        public:
            virtual void ping_event(
                const satcat5::ip::Addr& from, u32 elapsed_usec) = 0;
 
        private:
            // Linked list to the next listener object.
            friend satcat5::util::ListCore;
            satcat5::ip::PingListener* m_next;
        };
 
        class ProtoIcmp final
            : public satcat5::net::Protocol
            , protected satcat5::poll::Timer {
        public:
            ProtoIcmp(satcat5::ip::Dispatch* iface);
            ~ProtoIcmp() SATCAT5_OPTIONAL_DTOR;
 
            bool send_error(
                u16 type, satcat5::io::Readable* src, uint32_t arg = 0);
 
            bool send_ping(satcat5::ip::Address& dst);
 
            bool send_timereq(satcat5::ip::Address& dst);
 
            inline void set_log_cooldown(unsigned wait_msec)
                { m_wait_msec = wait_msec; }
 
            inline void add(satcat5::ip::PingListener* cb)
                {m_listeners.add(cb);}
            inline void remove(satcat5::ip::PingListener* cb)
                {m_listeners.remove(cb);}
 
        protected:
            void frame_rcvd(satcat5::io::LimitedRead& src) override;
            void timer_event() override;
            bool write_icmp(
                satcat5::io::Writeable* wr,
                unsigned wcount, u16* data);
 
            satcat5::ip::Dispatch* const m_iface;
            satcat5::util::List<satcat5::ip::PingListener> m_listeners;
            unsigned m_wait_msec;
        };
    }
}