router2_deferfwd.h

// Copyright 2024-2025 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
// Deferred packet forwarding for the IPv4 router
 
#pragma once
 
#include <satcat5/eth_arp.h>
#include <satcat5/eth_switch.h>
#include <satcat5/ip_core.h>
#include <satcat5/list.h>
#include <satcat5/timeref.h>
 
namespace satcat5 {
    namespace router2 {
        struct DeferPkt {
        public:
            // All data and metadata are public variables:
            satcat5::io::MultiPacket* pkt;  
            satcat5::ip::Addr dst_ip;       
            SATCAT5_PMASK_TYPE dst_mask;    
            u16 sent;                       
            u16 trem;                       
 
            // Explicitly declare default constructor and assignment methods.
            DeferPkt() = default;
            DeferPkt(const DeferPkt& t) = delete;
            DeferPkt& operator=(const DeferPkt& t) = delete;
 
            bool read_meta(satcat5::eth::PluginPacket& meta);
 
        private:
            // Linked list to the next packet object.
            friend satcat5::util::ListCore;
            satcat5::router2::DeferPkt* m_next;
        };
 
        class DeferFwd
            : public satcat5::eth::ArpListener
            , public satcat5::poll::Timer
        {
        public:
            bool accept(const satcat5::eth::PluginPacket& meta);
 
        protected:
            DeferFwd(
                satcat5::router2::Dispatch* parent,
                satcat5::router2::DeferPkt* buff,
                unsigned bcount);
            ~DeferFwd() SATCAT5_OPTIONAL_DTOR;
 
            // Event handler callbacks.
            void arp_event(
                const satcat5::eth::MacAddr& mac,
                const satcat5::ip::Addr& ip) override;
            void timer_event() override;
 
            // Packet handlers may mutate the active list,
            // so they return the next item to be processed.
            satcat5::router2::DeferPkt* request_arp(
                satcat5::router2::DeferPkt* pkt);
            satcat5::router2::DeferPkt* request_fwd(
                satcat5::router2::DeferPkt* pkt, const satcat5::eth::MacAddr& dst);
 
            // Pointers to upstream interface objects.
            satcat5::router2::Dispatch* const m_parent;
            satcat5::eth::ProtoArp* m_arp;
 
            // Reference for measuring elapsed time.
            satcat5::util::TimeVal m_tref;
 
            // Lists for empty and active packets.
            satcat5::util::List<satcat5::router2::DeferPkt> m_active;
            satcat5::util::List<satcat5::router2::DeferPkt> m_empty;
        };
 
        template <unsigned SIZE = SATCAT5_MBUFF_RXPKT>
        class DeferFwdStatic final : public satcat5::router2::DeferFwd {
        public:
            explicit DeferFwdStatic(satcat5::router2::Dispatch* parent)
                : DeferFwd(parent, m_buff, SIZE), m_buff{} {}
 
        protected:
            // Backing array for parent (i.e., m_active and m_empty).
            satcat5::router2::DeferPkt m_buff[SIZE];
        };
    }
}