udp_tftp.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/udp_socket.h>
 
namespace satcat5 {
    namespace udp {
        class TftpTransfer
            : public satcat5::net::Protocol
            , public satcat5::poll::Timer
        {
        public:
            explicit TftpTransfer(satcat5::udp::Dispatch* iface);
            ~TftpTransfer();
 
            inline bool active() const
                {return m_flags > 0;}
 
            inline u32 progress_blocks() const
                {return m_block_id;}
            inline u32 progress_bytes() const
                {return m_xfer_bytes;}
 
            void reset(const char* msg);
 
            void request(
                const satcat5::ip::Addr& dstaddr,
                u16 opcode, const char* filename);
 
            bool is_duplicate_request();
 
            void accept();
 
            void file_send(satcat5::io::Readable* src, bool now);
            void file_recv(satcat5::io::Writeable* dst, bool now);
 
            void send_error(u16 errcode);
 
        protected:
            friend satcat5::test::TftpClient;
            friend satcat5::test::TftpServer;
 
            // Inherited event handlers:
            void frame_rcvd(satcat5::io::LimitedRead& src) override;
            void timer_event() override;
 
            // Internal event handlers:
            void read_data(u16 block_id, satcat5::io::LimitedRead& src);
            void read_error(satcat5::io::LimitedRead& src);
            void send_ack(u16 block_id);
            void send_data(u16 block_id);
            void send_packet(unsigned len, u16 retry);
 
            // Interface objects.
            satcat5::udp::Address m_addr;
            satcat5::io::Readable* m_src;
            satcat5::io::Writeable* m_dst;
 
            // Transfer state uses soft-matching against an extended
            // 32-bit Block-ID to allow files larger than 32 MiB.
            u32 m_xfer_bytes;
            u32 m_block_id;
            u16 m_flags;
 
            // Internal buffer allows retransmission of lost packets.
            // (Max 4-byte header + 512 bytes data = 516 bytes.)
            u16 m_retry_count;
            u16 m_retry_len;
            u8 m_retry_buff[516];
        };
 
        class TftpClient
        {
        public:
            explicit TftpClient(satcat5::udp::Dispatch* iface);
            ~TftpClient() {}
 
            void begin_download(
                satcat5::io::Writeable* dst,
                const satcat5::ip::Addr& server,
                const char* filename);
 
            void begin_upload(
                satcat5::io::Readable* src,
                const satcat5::ip::Addr& server,
                const char* filename);
 
            inline bool active() const
                {return m_xfer.active();}
            inline u32 progress_blocks() const
                {return m_xfer.progress_blocks();}
            inline u32 progress_bytes() const
                {return m_xfer.progress_bytes();}
 
        protected:
            friend satcat5::test::TftpClient;
 
            // Upload or download state.
            satcat5::udp::TftpTransfer m_xfer;
        };
 
        class TftpServerCore : public satcat5::net::Protocol
        {
        public:
            inline bool active() const
                {return m_xfer.active();}
 
        protected:
            explicit TftpServerCore(satcat5::udp::Dispatch* iface);
            ~TftpServerCore();
 
            virtual satcat5::io::Readable* read(const char* filename) = 0;
            virtual satcat5::io::Writeable* write(const char* filename) = 0;
 
            // Inherited event handler for handling incoming packets.
            void frame_rcvd(satcat5::io::LimitedRead& src) override;
 
            // Connection to client (one at a time).
            satcat5::udp::Dispatch* const m_iface;
            satcat5::udp::TftpTransfer m_xfer;
        };
 
        class TftpServerSimple : public satcat5::udp::TftpServerCore {
        public:
            TftpServerSimple(
                satcat5::udp::Dispatch* iface,
                satcat5::io::Readable* src,
                satcat5::io::Writeable* dst);
            ~TftpServerSimple() {}
 
        protected:
            friend satcat5::test::TftpServer;
 
            // Required overrides from TftpServer.
            satcat5::io::Readable* read(const char* filename) override;
            satcat5::io::Writeable* write(const char* filename) override;
 
            // Interface objects.
            satcat5::io::Readable* const m_src;
            satcat5::io::Writeable* const m_dst;
        };
    }
}