udp_dispatch.h

// Copyright 2021-2025 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
// UDP Dispatcher sorts incoming messages by port index
 
#pragma once
 
#include <satcat5/ip_dispatch.h>
#include <satcat5/udp_core.h>
 
namespace satcat5 {
    namespace udp {
        class Dispatch final
            : public satcat5::net::Protocol
            , public satcat5::net::Dispatch
        {
        public:
            Dispatch(satcat5::ip::Dispatch* iface);
            ~Dispatch() SATCAT5_OPTIONAL_DTOR;
 
            satcat5::io::Writeable* open_reply(
                const satcat5::net::Type& type, unsigned nbytes) override;
 
            satcat5::io::Writeable* open_write(
                satcat5::ip::Address& addr,         // Destination IP+MAC
                const satcat5::udp::Port& src,      // Source port
                const satcat5::udp::Port& dst,      // Destination port
                unsigned len);                      // Length after UDP header
 
            // Other accessors.
            inline satcat5::eth::ProtoArp* arp() const
                { return m_iface->arp(); }
            inline satcat5::eth::Dispatch* eth() const
                { return m_iface->iface(); }
            inline satcat5::ip::Dispatch* iface() const
                { return m_iface; }
            inline satcat5::ip::Addr ipaddr() const
                { return m_iface->ipaddr(); }
            inline satcat5::eth::MacAddr macaddr() const
                { return m_iface->macaddr(); }
            inline satcat5::eth::VlanTag reply_vtag() const
                { return m_iface->reply_vtag(); }
            inline satcat5::eth::MacAddr reply_mac() const
                { return m_iface->reply_mac(); }
            inline bool reply_is_multicast() const
                { return m_iface->reply_is_multicast(); }
            inline satcat5::ip::Addr reply_ip() const
                { return m_iface->reply_ip(); }
            inline satcat5::udp::Port reply_src() const
                { return m_reply_src; }
            inline satcat5::udp::Port reply_dst() const
                { return m_reply_dst; }
 
            satcat5::udp::Port next_free_port();
 
        protected:
            // Event handler for incoming IPv4 frames.
            void frame_rcvd(satcat5::io::LimitedRead& src) override;
 
            // Pointer to the parent interface.
            satcat5::ip::Dispatch* const m_iface;
 
            // Next dynamically assigned port.
            u16 m_next_port;
 
            // The current reply parameters.
            satcat5::udp::Port m_reply_src;
            satcat5::udp::Port m_reply_dst;
        };
    }
}