ip_table.h

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// Copyright 2024-2025 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
 
#pragma once
 
#include <satcat5/eth_header.h>
#include <satcat5/ip_core.h>
 
// Set size of the static routing table, not including the default route.
// (To override, add gcc argument "-DSATCAT5_ROUTING_TABLE=32" etc.)
#ifndef SATCAT5_ROUTING_TABLE
#define SATCAT5_ROUTING_TABLE 8
#endif
 
namespace satcat5 {
    namespace ip {
        struct Route {
            // Contents of this table entry:
            satcat5::ip::Subnet subnet;     
            satcat5::ip::Addr gateway;      
            satcat5::eth::MacAddr dstmac;   
            u8 port;                        
            u8 flags;                       
 
            static constexpr u8 FLAG_PROXY_ARP = 0x01;
 
            static constexpr u8 FLAG_MAC_FIXED = 0x02;
 
            // Explicitly declare default constructor and copy methods.
            Route() = default;
            Route(const Route& t) = default;
            Route& operator=(const Route& t) = default;
 
            inline bool has_dstmac() const
                { return (dstmac != satcat5::eth::MACADDR_NONE); }
            inline bool has_gateway() const
                { return (gateway != satcat5::ip::ADDR_NONE); }
            inline bool is_deliverable() const
                { return has_dstmac() || has_gateway(); }
            inline bool is_multicast() const
                { return dstmac.is_multicast() || gateway.is_multicast(); }
            inline bool is_proxy_arp() const
                { return (flags & FLAG_PROXY_ARP) != 0; }
            inline bool is_unicast() const
                { return dstmac.is_unicast() || gateway.is_unicast(); }
 
            void log_to(satcat5::log::LogBuffer& wr) const;
        };
 
        class RouteArray {
        protected:
            RouteArray();
 
            inline const satcat5::ip::Route& route_rddef() const
                { return m_route_default; }
            virtual bool route_wrdef(const satcat5::ip::Route& route);
 
            inline const satcat5::ip::Route& route_read(unsigned idx) const
                { return m_route_table[idx]; }
            virtual bool route_write(unsigned idx, const satcat5::ip::Route& route);
 
        private:
            // Members are private to prevent accidental changes.
            satcat5::ip::Route m_route_default;
            satcat5::ip::Route m_route_table[SATCAT5_ROUTING_TABLE];
        };
 
        class Table : protected satcat5::ip::RouteArray {
        public:
            Table();
 
            void log_to(satcat5::log::LogBuffer& wr) const;
 
            void route_clear(bool lockdown = true);
 
            void route_flush();
 
            bool route_default(
                const satcat5::ip::Addr& gateway,
                const satcat5::eth::MacAddr& dstmac = satcat5::eth::MACADDR_NONE,
                u8 port = 0, u8 flags = 0);
 
            bool route_simple(
                const satcat5::ip::Addr& gateway,
                const satcat5::ip::Mask& subnet = satcat5::ip::MASK_24);
 
            bool route_static(
                const satcat5::ip::Subnet& subnet,
                const satcat5::ip::Addr& gateway,
                const satcat5::eth::MacAddr& dstmac = satcat5::eth::MACADDR_NONE,
                u8 port = 0, u8 flags = 0);
 
            bool route_local(
                const satcat5::ip::Subnet& subnet,
                u8 port = 0, u8 flags = 0)
            {
                return route_static(subnet,
                    satcat5::ip::ADDR_BROADCAST,
                    satcat5::eth::MACADDR_NONE,
                    port, flags);
            }
 
            bool route_cache(
                const satcat5::ip::Addr& gateway,
                const satcat5::eth::MacAddr& dstmac);
 
            bool route_remove(const satcat5::ip::Subnet& subnet);
            inline bool route_remove(const satcat5::ip::Addr& addr)
                { return route_remove({addr, ip::MASK_32}); }
 
            satcat5::ip::Route route_lookup(
                const satcat5::ip::Addr& dstaddr) const;
 
        protected:
            // Routing table state (in addition to RouteArray):
            // First N routes are static; the rest are ephemeral.
            unsigned m_wridx_static;
            unsigned m_wridx_ephemeral;
        };
    }
}