Merge pull request 'CFDP destination handler' (#62) from cfdp-state-machines into main

Reviewed-on: #62

satrs-core/Cargo.toml

@@ -17,10 +17,16 @@ delegate = ">0.7, <=0.10"
 paste = "1"
 embed-doc-image = "0.1"
 
+[dependencies.smallvec]
+version = "1"
+
 [dependencies.num_enum]
 version = ">0.5, <=0.7"
 default-features = false
 
+[dependencies.crc]
+version = "3"
+
 [dependencies.dyn-clone]
 version = "1"
 optional = true
@@ -83,6 +89,7 @@ serde = "1"
 zerocopy = "0.7"
 once_cell = "1.13"
 serde_json = "1"
+rand = "0.8"
 
 [dev-dependencies.postcard]
 version = "1"

satrs-core/src/cfdp/dest.rs

@@ -0,0 +1,871 @@
+use core::str::{from_utf8, Utf8Error};
+use std::{
+    fs::{metadata, File},
+    io::{BufReader, Read, Seek, SeekFrom, Write},
+    path::{Path, PathBuf},
+};
+
+use crate::cfdp::user::TransactionFinishedParams;
+
+use super::{
+    user::{CfdpUser, MetadataReceivedParams},
+    PacketInfo, PacketTarget, State, TransactionId, TransactionStep, CRC_32,
+};
+use smallvec::SmallVec;
+use spacepackets::{
+    cfdp::{
+        pdu::{
+            eof::EofPdu,
+            file_data::FileDataPdu,
+            finished::{DeliveryCode, FileStatus, FinishedPdu},
+            metadata::{MetadataGenericParams, MetadataPdu},
+            CommonPduConfig, FileDirectiveType, PduError, PduHeader,
+        },
+        tlv::{msg_to_user::MsgToUserTlv, EntityIdTlv, TlvType},
+        ConditionCode, PduType, TransmissionMode,
+    },
+    util::UnsignedByteField,
+};
+use thiserror::Error;
+
+pub struct DestinationHandler {
+    id: UnsignedByteField,
+    step: TransactionStep,
+    state: State,
+    tparams: TransactionParams,
+    packets_to_send_ctx: PacketsToSendContext,
+}
+
+#[derive(Debug, Default)]
+struct PacketsToSendContext {
+    packet_available: bool,
+    directive: Option<FileDirectiveType>,
+}
+
+#[derive(Debug)]
+struct FileProperties {
+    src_file_name: [u8; u8::MAX as usize],
+    src_file_name_len: usize,
+    dest_file_name: [u8; u8::MAX as usize],
+    dest_file_name_len: usize,
+    dest_path_buf: PathBuf,
+}
+
+#[derive(Debug)]
+struct TransferState {
+    transaction_id: Option<TransactionId>,
+    progress: usize,
+    condition_code: ConditionCode,
+    delivery_code: DeliveryCode,
+    file_status: FileStatus,
+    metadata_params: MetadataGenericParams,
+}
+
+impl Default for TransferState {
+    fn default() -> Self {
+        Self {
+            transaction_id: None,
+            progress: Default::default(),
+            condition_code: ConditionCode::NoError,
+            delivery_code: DeliveryCode::Incomplete,
+            file_status: FileStatus::Unreported,
+            metadata_params: Default::default(),
+        }
+    }
+}
+#[derive(Debug)]
+struct TransactionParams {
+    tstate: TransferState,
+    pdu_conf: CommonPduConfig,
+    file_properties: FileProperties,
+    cksum_buf: [u8; 1024],
+    msgs_to_user_size: usize,
+    msgs_to_user_buf: [u8; 1024],
+}
+
+impl Default for FileProperties {
+    fn default() -> Self {
+        Self {
+            src_file_name: [0; u8::MAX as usize],
+            src_file_name_len: Default::default(),
+            dest_file_name: [0; u8::MAX as usize],
+            dest_file_name_len: Default::default(),
+            dest_path_buf: Default::default(),
+        }
+    }
+}
+
+impl TransactionParams {
+    fn file_size(&self) -> usize {
+        self.tstate.metadata_params.file_size as usize
+    }
+
+    fn metadata_params(&self) -> &MetadataGenericParams {
+        &self.tstate.metadata_params
+    }
+}
+
+impl Default for TransactionParams {
+    fn default() -> Self {
+        Self {
+            pdu_conf: Default::default(),
+            cksum_buf: [0; 1024],
+            msgs_to_user_size: 0,
+            msgs_to_user_buf: [0; 1024],
+            tstate: Default::default(),
+            file_properties: Default::default(),
+        }
+    }
+}
+
+impl TransactionParams {
+    fn reset(&mut self) {
+        self.tstate.condition_code = ConditionCode::NoError;
+        self.tstate.delivery_code = DeliveryCode::Incomplete;
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum DestError {
+    /// File directive expected, but none specified
+    #[error("expected file directive")]
+    DirectiveExpected,
+    #[error("can not process packet type {0:?}")]
+    CantProcessPacketType(FileDirectiveType),
+    #[error("can not process file data PDUs in current state")]
+    WrongStateForFileDataAndEof,
+    // Received new metadata PDU while being already being busy with a file transfer.
+    #[error("busy with transfer")]
+    RecvdMetadataButIsBusy,
+    #[error("empty source file field")]
+    EmptySrcFileField,
+    #[error("empty dest file field")]
+    EmptyDestFileField,
+    #[error("pdu error {0}")]
+    Pdu(#[from] PduError),
+    #[error("io error {0}")]
+    Io(#[from] std::io::Error),
+    #[error("path conversion error {0}")]
+    PathConversion(#[from] Utf8Error),
+    #[error("error building dest path from source file name and dest folder")]
+    PathConcatError,
+}
+
+impl DestinationHandler {
+    pub fn new(id: impl Into<UnsignedByteField>) -> Self {
+        Self {
+            id: id.into(),
+            step: TransactionStep::Idle,
+            state: State::Idle,
+            tparams: Default::default(),
+            packets_to_send_ctx: Default::default(),
+        }
+    }
+
+    pub fn state_machine(&mut self, cfdp_user: &mut impl CfdpUser) -> Result<(), DestError> {
+        match self.state {
+            State::Idle => todo!(),
+            State::BusyClass1Nacked => self.fsm_nacked(cfdp_user),
+            State::BusyClass2Acked => todo!("acknowledged mode not implemented yet"),
+        }
+    }
+
+    pub fn insert_packet(&mut self, packet_info: &PacketInfo) -> Result<(), DestError> {
+        if packet_info.target() != PacketTarget::DestEntity {
+            // Unwrap is okay here, a PacketInfo for a file data PDU should always have the
+            // destination as the target.
+            return Err(DestError::CantProcessPacketType(
+                packet_info.pdu_directive().unwrap(),
+            ));
+        }
+        match packet_info.pdu_type {
+            PduType::FileDirective => {
+                if packet_info.pdu_directive.is_none() {
+                    return Err(DestError::DirectiveExpected);
+                }
+                self.handle_file_directive(
+                    packet_info.pdu_directive.unwrap(),
+                    packet_info.raw_packet,
+                )
+            }
+            PduType::FileData => self.handle_file_data(packet_info.raw_packet),
+        }
+    }
+
+    pub fn packet_to_send_ready(&self) -> bool {
+        self.packets_to_send_ctx.packet_available
+    }
+
+    pub fn get_next_packet_to_send(
+        &self,
+        buf: &mut [u8],
+    ) -> Result<Option<(FileDirectiveType, usize)>, DestError> {
+        if !self.packet_to_send_ready() {
+            return Ok(None);
+        }
+        let directive = self.packets_to_send_ctx.directive.unwrap();
+        let written_size = match directive {
+            FileDirectiveType::FinishedPdu => {
+                let pdu_header = PduHeader::new_no_file_data(self.tparams.pdu_conf, 0);
+                let finished_pdu = if self.tparams.tstate.condition_code == ConditionCode::NoError
+                    || self.tparams.tstate.condition_code == ConditionCode::UnsupportedChecksumType
+                {
+                    FinishedPdu::new_default(
+                        pdu_header,
+                        self.tparams.tstate.delivery_code,
+                        self.tparams.tstate.file_status,
+                    )
+                } else {
+                    // TODO: Are there cases where this ID is actually the source entity ID?
+                    let entity_id = EntityIdTlv::new(self.id);
+                    FinishedPdu::new_with_error(
+                        pdu_header,
+                        self.tparams.tstate.condition_code,
+                        self.tparams.tstate.delivery_code,
+                        self.tparams.tstate.file_status,
+                        entity_id,
+                    )
+                };
+                finished_pdu.write_to_bytes(buf)?
+            }
+            FileDirectiveType::AckPdu => todo!(),
+            FileDirectiveType::NakPdu => todo!(),
+            FileDirectiveType::KeepAlivePdu => todo!(),
+            _ => {
+                // This should never happen and is considered an internal impl error
+                panic!("invalid file directive {directive:?} for dest handler send packet");
+            }
+        };
+        Ok(Some((directive, written_size)))
+    }
+
+    pub fn handle_file_directive(
+        &mut self,
+        pdu_directive: FileDirectiveType,
+        raw_packet: &[u8],
+    ) -> Result<(), DestError> {
+        match pdu_directive {
+            FileDirectiveType::EofPdu => self.handle_eof_pdu(raw_packet)?,
+            FileDirectiveType::FinishedPdu
+            | FileDirectiveType::NakPdu
+            | FileDirectiveType::KeepAlivePdu => {
+                return Err(DestError::CantProcessPacketType(pdu_directive));
+            }
+            FileDirectiveType::AckPdu => {
+                todo!(
+                "check whether ACK pdu handling is applicable by checking the acked directive field"
+                )
+            }
+            FileDirectiveType::MetadataPdu => self.handle_metadata_pdu(raw_packet)?,
+            FileDirectiveType::PromptPdu => self.handle_prompt_pdu(raw_packet)?,
+        };
+        Ok(())
+    }
+
+    pub fn handle_metadata_pdu(&mut self, raw_packet: &[u8]) -> Result<(), DestError> {
+        if self.state != State::Idle {
+            return Err(DestError::RecvdMetadataButIsBusy);
+        }
+        let metadata_pdu = MetadataPdu::from_bytes(raw_packet)?;
+        self.tparams.reset();
+        self.tparams.tstate.metadata_params = *metadata_pdu.metadata_params();
+        let src_name = metadata_pdu.src_file_name();
+        if src_name.is_empty() {
+            return Err(DestError::EmptySrcFileField);
+        }
+        self.tparams.file_properties.src_file_name[..src_name.len_value()]
+            .copy_from_slice(src_name.value());
+        self.tparams.file_properties.src_file_name_len = src_name.len_value();
+        let dest_name = metadata_pdu.dest_file_name();
+        if dest_name.is_empty() {
+            return Err(DestError::EmptyDestFileField);
+        }
+        self.tparams.file_properties.dest_file_name[..dest_name.len_value()]
+            .copy_from_slice(dest_name.value());
+        self.tparams.file_properties.dest_file_name_len = dest_name.len_value();
+        self.tparams.pdu_conf = *metadata_pdu.pdu_header().common_pdu_conf();
+        self.tparams.msgs_to_user_size = 0;
+        if metadata_pdu.options().is_some() {
+            for option_tlv in metadata_pdu.options_iter().unwrap() {
+                if option_tlv.is_standard_tlv()
+                    && option_tlv.tlv_type().unwrap() == TlvType::MsgToUser
+                {
+                    self.tparams
+                        .msgs_to_user_buf
+                        .copy_from_slice(option_tlv.raw_data().unwrap());
+                    self.tparams.msgs_to_user_size += option_tlv.len_full();
+                }
+            }
+        }
+        if self.tparams.pdu_conf.trans_mode == TransmissionMode::Unacknowledged {
+            self.state = State::BusyClass1Nacked;
+        } else {
+            self.state = State::BusyClass2Acked;
+        }
+        self.step = TransactionStep::TransactionStart;
+        Ok(())
+    }
+
+    pub fn handle_file_data(&mut self, raw_packet: &[u8]) -> Result<(), DestError> {
+        if self.state == State::Idle || self.step != TransactionStep::ReceivingFileDataPdus {
+            return Err(DestError::WrongStateForFileDataAndEof);
+        }
+        let fd_pdu = FileDataPdu::from_bytes(raw_packet)?;
+        let mut dest_file = File::options()
+            .write(true)
+            .open(&self.tparams.file_properties.dest_path_buf)?;
+        dest_file.seek(SeekFrom::Start(fd_pdu.offset()))?;
+        dest_file.write_all(fd_pdu.file_data())?;
+        Ok(())
+    }
+
+    #[allow(clippy::needless_if)]
+    pub fn handle_eof_pdu(&mut self, raw_packet: &[u8]) -> Result<(), DestError> {
+        if self.state == State::Idle || self.step != TransactionStep::ReceivingFileDataPdus {
+            return Err(DestError::WrongStateForFileDataAndEof);
+        }
+        let eof_pdu = EofPdu::from_bytes(raw_packet)?;
+        let checksum = eof_pdu.file_checksum();
+        // For a standard disk based file system, which is assumed to be used for now, the file
+        // will always be retained. This might change in the future.
+        self.tparams.tstate.file_status = FileStatus::Retained;
+        if self.checksum_check(checksum)? {
+            self.tparams.tstate.condition_code = ConditionCode::NoError;
+            self.tparams.tstate.delivery_code = DeliveryCode::Complete;
+        } else {
+            self.tparams.tstate.condition_code = ConditionCode::FileChecksumFailure;
+        }
+        // TODO: Check progress, and implement transfer completion timer as specified in the
+        // standard. This timer protects against out of order arrival of packets.
+        if self.tparams.tstate.progress != self.tparams.file_size() {}
+        if self.state == State::BusyClass1Nacked {
+            self.step = TransactionStep::TransferCompletion;
+        } else {
+            self.step = TransactionStep::SendingAckPdu;
+        }
+        Ok(())
+    }
+
+    pub fn handle_prompt_pdu(&mut self, _raw_packet: &[u8]) -> Result<(), DestError> {
+        todo!();
+    }
+
+    fn checksum_check(&mut self, expected_checksum: u32) -> Result<bool, DestError> {
+        let mut digest = CRC_32.digest();
+        let file_to_check = File::open(&self.tparams.file_properties.dest_path_buf)?;
+        let mut buf_reader = BufReader::new(file_to_check);
+        loop {
+            let bytes_read = buf_reader.read(&mut self.tparams.cksum_buf)?;
+            if bytes_read == 0 {
+                break;
+            }
+            digest.update(&self.tparams.cksum_buf[0..bytes_read]);
+        }
+        if digest.finalize() == expected_checksum {
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    fn fsm_nacked(&mut self, cfdp_user: &mut impl CfdpUser) -> Result<(), DestError> {
+        if self.step == TransactionStep::TransactionStart {
+            self.transaction_start(cfdp_user)?;
+        }
+        if self.step == TransactionStep::TransferCompletion {
+            self.transfer_completion(cfdp_user)?;
+        }
+        if self.step == TransactionStep::SendingAckPdu {
+            todo!("no support for acknowledged mode yet");
+        }
+        if self.step == TransactionStep::SendingFinishedPdu {
+            self.reset();
+        }
+        Ok(())
+    }
+
+    /// Get the step, which denotes the exact step of a pending CFDP transaction when applicable.
+    pub fn step(&self) -> TransactionStep {
+        self.step
+    }
+
+    /// Get the step, which denotes whether the CFDP handler is active, and which CFDP class
+    /// is used if it is active.
+    pub fn state(&self) -> State {
+        self.state
+    }
+
+    fn transaction_start(&mut self, cfdp_user: &mut impl CfdpUser) -> Result<(), DestError> {
+        let dest_name = from_utf8(
+            &self.tparams.file_properties.dest_file_name
+                [..self.tparams.file_properties.dest_file_name_len],
+        )?;
+        let dest_path = Path::new(dest_name);
+        self.tparams.file_properties.dest_path_buf = dest_path.to_path_buf();
+        let source_id = self.tparams.pdu_conf.source_id();
+        let id = TransactionId::new(source_id, self.tparams.pdu_conf.transaction_seq_num);
+        let src_name = from_utf8(
+            &self.tparams.file_properties.src_file_name
+                [0..self.tparams.file_properties.src_file_name_len],
+        )?;
+        let mut msgs_to_user = SmallVec::<[MsgToUserTlv<'_>; 16]>::new();
+        let mut num_msgs_to_user = 0;
+        if self.tparams.msgs_to_user_size > 0 {
+            let mut index = 0;
+            while index < self.tparams.msgs_to_user_size {
+                // This should never panic as the validity of the options was checked beforehand.
+                let msgs_to_user_tlv =
+                    MsgToUserTlv::from_bytes(&self.tparams.msgs_to_user_buf[index..])
+                        .expect("message to user creation failed unexpectedly");
+                msgs_to_user.push(msgs_to_user_tlv);
+                index += msgs_to_user_tlv.len_full();
+                num_msgs_to_user += 1;
+            }
+        }
+        let metadata_recvd_params = MetadataReceivedParams {
+            id,
+            source_id,
+            file_size: self.tparams.tstate.metadata_params.file_size,
+            src_file_name: src_name,
+            dest_file_name: dest_name,
+            msgs_to_user: &msgs_to_user[..num_msgs_to_user],
+        };
+        self.tparams.tstate.transaction_id = Some(id);
+        cfdp_user.metadata_recvd_indication(&metadata_recvd_params);
+
+        if dest_path.exists() {
+            let dest_metadata = metadata(dest_path)?;
+            if dest_metadata.is_dir() {
+                // Create new destination path by concatenating the last part of the source source
+                // name and the destination folder. For example, for a source file of /tmp/hello.txt
+                // and a destination name of /home/test, the resulting file name should be
+                // /home/test/hello.txt
+                let source_path = Path::new(from_utf8(
+                    &self.tparams.file_properties.src_file_name
+                        [..self.tparams.file_properties.src_file_name_len],
+                )?);
+
+                let source_name = source_path.file_name();
+                if source_name.is_none() {
+                    return Err(DestError::PathConcatError);
+                }
+                let source_name = source_name.unwrap();
+                self.tparams.file_properties.dest_path_buf.push(source_name);
+            }
+        }
+        // This function does exactly what we require: Create a new file if it does not exist yet
+        // and trucate an existing one.
+        File::create(&self.tparams.file_properties.dest_path_buf)?;
+        self.step = TransactionStep::ReceivingFileDataPdus;
+        Ok(())
+    }
+
+    fn transfer_completion(&mut self, cfdp_user: &mut impl CfdpUser) -> Result<(), DestError> {
+        let transaction_finished_params = TransactionFinishedParams {
+            id: self.tparams.tstate.transaction_id.unwrap(),
+            condition_code: self.tparams.tstate.condition_code,
+            delivery_code: self.tparams.tstate.delivery_code,
+            file_status: self.tparams.tstate.file_status,
+        };
+        cfdp_user.transaction_finished_indication(&transaction_finished_params);
+        // This function should never be called with metadata parameters not set
+        if self.tparams.metadata_params().closure_requested {
+            self.prepare_finished_pdu()?;
+            self.step = TransactionStep::SendingFinishedPdu;
+        } else {
+            self.reset();
+            self.state = State::Idle;
+            self.step = TransactionStep::Idle;
+        }
+        Ok(())
+    }
+
+    fn reset(&mut self) {
+        self.step = TransactionStep::Idle;
+        self.state = State::Idle;
+        self.packets_to_send_ctx.packet_available = false;
+        self.tparams.reset();
+    }
+
+    fn prepare_finished_pdu(&mut self) -> Result<(), DestError> {
+        self.packets_to_send_ctx.packet_available = true;
+        self.packets_to_send_ctx.directive = Some(FileDirectiveType::FinishedPdu);
+        self.step = TransactionStep::SendingFinishedPdu;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use core::sync::atomic::{AtomicU8, Ordering};
+    #[allow(unused_imports)]
+    use std::println;
+    use std::{env::temp_dir, fs};
+
+    use alloc::{format, string::String};
+    use rand::Rng;
+    use spacepackets::{
+        cfdp::{lv::Lv, ChecksumType},
+        util::{UbfU16, UnsignedByteFieldU16},
+    };
+
+    use super::*;
+
+    const LOCAL_ID: UnsignedByteFieldU16 = UnsignedByteFieldU16::new(1);
+    const REMOTE_ID: UnsignedByteFieldU16 = UnsignedByteFieldU16::new(2);
+
+    const SRC_NAME: &str = "__cfdp__source-file";
+    const DEST_NAME: &str = "__cfdp__dest-file";
+
+    static ATOMIC_COUNTER: AtomicU8 = AtomicU8::new(0);
+
+    #[derive(Default)]
+    struct TestCfdpUser {
+        next_expected_seq_num: u64,
+        expected_full_src_name: String,
+        expected_full_dest_name: String,
+        expected_file_size: usize,
+    }
+
+    impl TestCfdpUser {
+        fn generic_id_check(&self, id: &crate::cfdp::TransactionId) {
+            assert_eq!(id.source_id, LOCAL_ID.into());
+            assert_eq!(id.seq_num().value(), self.next_expected_seq_num);
+        }
+    }
+
+    impl CfdpUser for TestCfdpUser {
+        fn transaction_indication(&mut self, id: &crate::cfdp::TransactionId) {
+            self.generic_id_check(id);
+        }
+
+        fn eof_sent_indication(&mut self, id: &crate::cfdp::TransactionId) {
+            self.generic_id_check(id);
+        }
+
+        fn transaction_finished_indication(
+            &mut self,
+            finished_params: &crate::cfdp::user::TransactionFinishedParams,
+        ) {
+            self.generic_id_check(&finished_params.id);
+        }
+
+        fn metadata_recvd_indication(
+            &mut self,
+            md_recvd_params: &crate::cfdp::user::MetadataReceivedParams,
+        ) {
+            self.generic_id_check(&md_recvd_params.id);
+            assert_eq!(
+                String::from(md_recvd_params.src_file_name),
+                self.expected_full_src_name
+            );
+            assert_eq!(
+                String::from(md_recvd_params.dest_file_name),
+                self.expected_full_dest_name
+            );
+            assert_eq!(md_recvd_params.msgs_to_user.len(), 0);
+            assert_eq!(md_recvd_params.source_id, LOCAL_ID.into());
+            assert_eq!(md_recvd_params.file_size as usize, self.expected_file_size);
+        }
+
+        fn file_segment_recvd_indication(
+            &mut self,
+            _segment_recvd_params: &crate::cfdp::user::FileSegmentRecvdParams,
+        ) {
+        }
+
+        fn report_indication(&mut self, _id: &crate::cfdp::TransactionId) {}
+
+        fn suspended_indication(
+            &mut self,
+            _id: &crate::cfdp::TransactionId,
+            _condition_code: ConditionCode,
+        ) {
+            panic!("unexpected suspended indication");
+        }
+
+        fn resumed_indication(&mut self, _id: &crate::cfdp::TransactionId, _progresss: u64) {}
+
+        fn fault_indication(
+            &mut self,
+            _id: &crate::cfdp::TransactionId,
+            _condition_code: ConditionCode,
+            _progress: u64,
+        ) {
+            panic!("unexpected fault indication");
+        }
+
+        fn abandoned_indication(
+            &mut self,
+            _id: &crate::cfdp::TransactionId,
+            _condition_code: ConditionCode,
+            _progress: u64,
+        ) {
+            panic!("unexpected abandoned indication");
+        }
+
+        fn eof_recvd_indication(&mut self, id: &crate::cfdp::TransactionId) {
+            self.generic_id_check(id);
+        }
+    }
+
+    fn init_check(handler: &DestinationHandler) {
+        assert_eq!(handler.state(), State::Idle);
+        assert_eq!(handler.step(), TransactionStep::Idle);
+    }
+
+    fn init_full_filenames() -> (PathBuf, PathBuf) {
+        let mut file_path = temp_dir();
+        let mut src_path = file_path.clone();
+        // Atomic counter used to allow concurrent tests.
+        let unique_counter = ATOMIC_COUNTER.fetch_add(1, Ordering::Relaxed);
+        // Create unique test filenames.
+        let src_name_unique = format!("{SRC_NAME}{}.txt", unique_counter);
+        let dest_name_unique = format!("{DEST_NAME}{}.txt", unique_counter);
+        src_path.push(src_name_unique);
+        file_path.push(dest_name_unique);
+        (src_path, file_path)
+    }
+
+    #[test]
+    fn test_basic() {
+        let dest_handler = DestinationHandler::new(REMOTE_ID);
+        init_check(&dest_handler);
+    }
+
+    fn create_pdu_header(seq_num: impl Into<UnsignedByteField>) -> PduHeader {
+        let mut pdu_conf =
+            CommonPduConfig::new_with_byte_fields(LOCAL_ID, REMOTE_ID, seq_num).unwrap();
+        pdu_conf.trans_mode = TransmissionMode::Unacknowledged;
+        PduHeader::new_no_file_data(pdu_conf, 0)
+    }
+
+    fn create_metadata_pdu<'filename>(
+        pdu_header: &PduHeader,
+        src_name: &'filename Path,
+        dest_name: &'filename Path,
+        file_size: u64,
+    ) -> MetadataPdu<'filename, 'filename, 'static> {
+        let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, file_size);
+        MetadataPdu::new(
+            *pdu_header,
+            metadata_params,
+            Lv::new_from_str(src_name.as_os_str().to_str().unwrap()).unwrap(),
+            Lv::new_from_str(dest_name.as_os_str().to_str().unwrap()).unwrap(),
+            None,
+        )
+    }
+
+    fn insert_metadata_pdu(
+        metadata_pdu: &MetadataPdu,
+        buf: &mut [u8],
+        dest_handler: &mut DestinationHandler,
+    ) {
+        let written_len = metadata_pdu
+            .write_to_bytes(buf)
+            .expect("writing metadata PDU failed");
+        let packet_info =
+            PacketInfo::new(&buf[..written_len]).expect("generating packet info failed");
+        let insert_result = dest_handler.insert_packet(&packet_info);
+        if let Err(e) = insert_result {
+            panic!("insert result error: {e}");
+        }
+    }
+
+    fn insert_eof_pdu(
+        file_data: &[u8],
+        pdu_header: &PduHeader,
+        buf: &mut [u8],
+        dest_handler: &mut DestinationHandler,
+    ) {
+        let mut digest = CRC_32.digest();
+        digest.update(file_data);
+        let crc32 = digest.finalize();
+        let eof_pdu = EofPdu::new_no_error(*pdu_header, crc32, file_data.len() as u64);
+        let result = eof_pdu.write_to_bytes(buf);
+        assert!(result.is_ok());
+        let packet_info = PacketInfo::new(&buf).expect("generating packet info failed");
+        let result = dest_handler.insert_packet(&packet_info);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_empty_file_transfer() {
+        let (src_name, dest_name) = init_full_filenames();
+        assert!(!Path::exists(&dest_name));
+        let mut buf: [u8; 512] = [0; 512];
+        let mut test_user = TestCfdpUser {
+            next_expected_seq_num: 0,
+            expected_full_src_name: src_name.to_string_lossy().into(),
+            expected_full_dest_name: dest_name.to_string_lossy().into(),
+            expected_file_size: 0,
+        };
+        // We treat the destination handler like it is a remote entity.
+        let mut dest_handler = DestinationHandler::new(REMOTE_ID);
+        init_check(&dest_handler);
+
+        let seq_num = UbfU16::new(0);
+        let pdu_header = create_pdu_header(seq_num);
+        let metadata_pdu =
+            create_metadata_pdu(&pdu_header, src_name.as_path(), dest_name.as_path(), 0);
+        insert_metadata_pdu(&metadata_pdu, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        if let Err(e) = result {
+            panic!("dest handler fsm error: {e}");
+        }
+        assert_ne!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::ReceivingFileDataPdus);
+
+        insert_eof_pdu(&[], &pdu_header, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+        assert_eq!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::Idle);
+        assert!(Path::exists(&dest_name));
+        let read_content = fs::read(&dest_name).expect("reading back string failed");
+        assert_eq!(read_content.len(), 0);
+        assert!(fs::remove_file(dest_name).is_ok());
+    }
+
+    #[test]
+    fn test_small_file_transfer() {
+        let (src_name, dest_name) = init_full_filenames();
+        assert!(!Path::exists(&dest_name));
+        let file_data_str = "Hello World!";
+        let file_data = file_data_str.as_bytes();
+        let mut buf: [u8; 512] = [0; 512];
+        let mut test_user = TestCfdpUser {
+            next_expected_seq_num: 0,
+            expected_full_src_name: src_name.to_string_lossy().into(),
+            expected_full_dest_name: dest_name.to_string_lossy().into(),
+            expected_file_size: file_data.len(),
+        };
+        // We treat the destination handler like it is a remote entity.
+        let mut dest_handler = DestinationHandler::new(REMOTE_ID);
+        init_check(&dest_handler);
+
+        let seq_num = UbfU16::new(0);
+        let pdu_header = create_pdu_header(seq_num);
+        let metadata_pdu = create_metadata_pdu(
+            &pdu_header,
+            src_name.as_path(),
+            dest_name.as_path(),
+            file_data.len() as u64,
+        );
+        insert_metadata_pdu(&metadata_pdu, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        if let Err(e) = result {
+            panic!("dest handler fsm error: {e}");
+        }
+        assert_ne!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::ReceivingFileDataPdus);
+
+        let offset = 0;
+        let filedata_pdu = FileDataPdu::new_no_seg_metadata(pdu_header, offset, file_data);
+        filedata_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing file data PDU failed");
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        let result = dest_handler.insert_packet(&packet_info);
+        if let Err(e) = result {
+            panic!("destination handler packet insertion error: {e}");
+        }
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+
+        insert_eof_pdu(file_data, &pdu_header, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+        assert_eq!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::Idle);
+
+        assert!(Path::exists(&dest_name));
+        let read_content = fs::read_to_string(&dest_name).expect("reading back string failed");
+        assert_eq!(read_content, file_data_str);
+        assert!(fs::remove_file(dest_name).is_ok());
+    }
+
+    #[test]
+    fn test_segmented_file_transfer() {
+        let (src_name, dest_name) = init_full_filenames();
+        assert!(!Path::exists(&dest_name));
+        let mut rng = rand::thread_rng();
+        let mut random_data = [0u8; 512];
+        rng.fill(&mut random_data);
+        let mut buf: [u8; 512] = [0; 512];
+        let mut test_user = TestCfdpUser {
+            next_expected_seq_num: 0,
+            expected_full_src_name: src_name.to_string_lossy().into(),
+            expected_full_dest_name: dest_name.to_string_lossy().into(),
+            expected_file_size: random_data.len(),
+        };
+
+        // We treat the destination handler like it is a remote entity.
+        let mut dest_handler = DestinationHandler::new(REMOTE_ID);
+        init_check(&dest_handler);
+
+        let seq_num = UbfU16::new(0);
+        let pdu_header = create_pdu_header(seq_num);
+        let metadata_pdu = create_metadata_pdu(
+            &pdu_header,
+            src_name.as_path(),
+            dest_name.as_path(),
+            random_data.len() as u64,
+        );
+        insert_metadata_pdu(&metadata_pdu, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        if let Err(e) = result {
+            panic!("dest handler fsm error: {e}");
+        }
+        assert_ne!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::ReceivingFileDataPdus);
+
+        // First file data PDU
+        let mut offset: usize = 0;
+        let segment_len = 256;
+        let filedata_pdu = FileDataPdu::new_no_seg_metadata(
+            pdu_header,
+            offset as u64,
+            &random_data[0..segment_len],
+        );
+        filedata_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing file data PDU failed");
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        let result = dest_handler.insert_packet(&packet_info);
+        if let Err(e) = result {
+            panic!("destination handler packet insertion error: {e}");
+        }
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+
+        // Second file data PDU
+        offset += segment_len;
+        let filedata_pdu = FileDataPdu::new_no_seg_metadata(
+            pdu_header,
+            offset as u64,
+            &random_data[segment_len..],
+        );
+        filedata_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing file data PDU failed");
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        let result = dest_handler.insert_packet(&packet_info);
+        if let Err(e) = result {
+            panic!("destination handler packet insertion error: {e}");
+        }
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+
+        insert_eof_pdu(&random_data, &pdu_header, &mut buf, &mut dest_handler);
+        let result = dest_handler.state_machine(&mut test_user);
+        assert!(result.is_ok());
+        assert_eq!(dest_handler.state(), State::Idle);
+        assert_eq!(dest_handler.step(), TransactionStep::Idle);
+
+        // Clean up
+        assert!(Path::exists(&dest_name));
+        let read_content = fs::read(&dest_name).expect("reading back string failed");
+        assert_eq!(read_content, random_data);
+        assert!(fs::remove_file(dest_name).is_ok());
+    }
+}

satrs-core/src/cfdp/mod.rs

@@ -0,0 +1,320 @@
+use crc::{Crc, CRC_32_CKSUM};
+use spacepackets::{
+    cfdp::{
+        pdu::{FileDirectiveType, PduError, PduHeader},
+        ChecksumType, PduType, TransmissionMode,
+    },
+    util::UnsignedByteField,
+};
+
+#[cfg(feature = "alloc")]
+use alloc::boxed::Box;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+#[cfg(feature = "std")]
+pub mod dest;
+#[cfg(feature = "std")]
+pub mod source;
+pub mod user;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EntityType {
+    Sending,
+    Receiving,
+}
+
+/// Generic abstraction for a check timer which has different functionality depending on whether
+/// the using entity is the sending entity or the receiving entity for the unacknowledged
+/// transmission mode.
+///
+/// For the sending entity, this timer determines the expiry period for declaring a check limit
+/// fault after sending an EOF PDU with requested closure. This allows a timeout of the transfer.
+/// Also see 4.6.3.2 of the CFDP standard.
+///
+/// For the receiving entity, this timer determines the expiry period for incrementing a check
+/// counter after an EOF PDU is received for an incomplete file transfer. This allows out-of-order
+/// reception of file data PDUs and EOF PDUs. Also see 4.6.3.3 of the CFDP standard.
+pub trait CheckTimerProvider {
+    fn has_expired(&self) -> bool;
+}
+
+/// A generic trait which allows CFDP entities to create check timers which are required to
+/// implement special procedures in unacknowledged transmission mode, as specified in 4.6.3.2
+/// and 4.6.3.3. The [CheckTimerProvider] provides more information about the purpose of the
+/// check timer.
+///
+/// This trait also allows the creation of different check timers depending on
+/// the ID of the local entity, the ID of the remote entity for a given transaction, and the
+/// type of entity.
+#[cfg(feature = "alloc")]
+pub trait CheckTimerCreator {
+    fn get_check_timer_provider(
+        local_id: &UnsignedByteField,
+        remote_id: &UnsignedByteField,
+        entity_type: EntityType,
+    ) -> Box<dyn CheckTimerProvider>;
+}
+
+/// Simple implementation of the [CheckTimerProvider] trait assuming a standard runtime.
+/// It also assumes that a second accuracy of the check timer period is sufficient.
+#[cfg(feature = "std")]
+pub struct StdCheckTimer {
+    expiry_time_seconds: u64,
+    start_time: std::time::Instant,
+}
+
+#[cfg(feature = "std")]
+impl StdCheckTimer {
+    pub fn new(expiry_time_seconds: u64) -> Self {
+        Self {
+            expiry_time_seconds,
+            start_time: std::time::Instant::now(),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl CheckTimerProvider for StdCheckTimer {
+    fn has_expired(&self) -> bool {
+        let elapsed_time = self.start_time.elapsed();
+        if elapsed_time.as_secs() > self.expiry_time_seconds {
+            return true;
+        }
+        false
+    }
+}
+
+#[derive(Debug)]
+pub struct RemoteEntityConfig {
+    pub entity_id: UnsignedByteField,
+    pub max_file_segment_len: usize,
+    pub closure_requeted_by_default: bool,
+    pub crc_on_transmission_by_default: bool,
+    pub default_transmission_mode: TransmissionMode,
+    pub default_crc_type: ChecksumType,
+    pub check_limit: u32,
+}
+
+pub trait RemoteEntityConfigProvider {
+    fn get_remote_config(&self, remote_id: &UnsignedByteField) -> Option<&RemoteEntityConfig>;
+}
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct TransactionId {
+    source_id: UnsignedByteField,
+    seq_num: UnsignedByteField,
+}
+
+impl TransactionId {
+    pub fn new(source_id: UnsignedByteField, seq_num: UnsignedByteField) -> Self {
+        Self { source_id, seq_num }
+    }
+
+    pub fn source_id(&self) -> &UnsignedByteField {
+        &self.source_id
+    }
+
+    pub fn seq_num(&self) -> &UnsignedByteField {
+        &self.seq_num
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum TransactionStep {
+    Idle = 0,
+    TransactionStart = 1,
+    ReceivingFileDataPdus = 2,
+    SendingAckPdu = 3,
+    TransferCompletion = 4,
+    SendingFinishedPdu = 5,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum State {
+    Idle = 0,
+    BusyClass1Nacked = 2,
+    BusyClass2Acked = 3,
+}
+
+pub const CRC_32: Crc<u32> = Crc::<u32>::new(&CRC_32_CKSUM);
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum PacketTarget {
+    SourceEntity,
+    DestEntity,
+}
+
+/// This is a helper struct which contains base information about a particular PDU packet.
+/// This is also necessary information for CFDP packet routing. For example, some packet types
+/// like file data PDUs can only be used by CFDP source entities.
+pub struct PacketInfo<'raw_packet> {
+    pdu_type: PduType,
+    pdu_directive: Option<FileDirectiveType>,
+    target: PacketTarget,
+    raw_packet: &'raw_packet [u8],
+}
+
+impl<'raw> PacketInfo<'raw> {
+    pub fn new(raw_packet: &'raw [u8]) -> Result<Self, PduError> {
+        let (pdu_header, header_len) = PduHeader::from_bytes(raw_packet)?;
+        if pdu_header.pdu_type() == PduType::FileData {
+            return Ok(Self {
+                pdu_type: pdu_header.pdu_type(),
+                pdu_directive: None,
+                target: PacketTarget::DestEntity,
+                raw_packet,
+            });
+        }
+        if pdu_header.pdu_datafield_len() < 1 {
+            return Err(PduError::FormatError);
+        }
+        // Route depending on PDU type and directive type if applicable. Retrieve directive type
+        // from the raw stream for better performance (with sanity and directive code check).
+        // The routing is based on section 4.5 of the CFDP standard which specifies the PDU forwarding
+        // procedure.
+        let directive = FileDirectiveType::try_from(raw_packet[header_len]).map_err(|_| {
+            PduError::InvalidDirectiveType {
+                found: raw_packet[header_len],
+                expected: None,
+            }
+        })?;
+        let packet_target = match directive {
+            // Section c) of 4.5.3: These PDUs should always be targeted towards the file sender a.k.a.
+            // the source handler
+            FileDirectiveType::NakPdu
+            | FileDirectiveType::FinishedPdu
+            | FileDirectiveType::KeepAlivePdu => PacketTarget::SourceEntity,
+            // Section b) of 4.5.3: These PDUs should always be targeted towards the file receiver a.k.a.
+            // the destination handler
+            FileDirectiveType::MetadataPdu
+            | FileDirectiveType::EofPdu
+            | FileDirectiveType::PromptPdu => PacketTarget::DestEntity,
+            // Section a): Recipient depends of the type of PDU that is being acknowledged. We can simply
+            // extract the PDU type from the raw stream. If it is an EOF PDU, this packet is passed to
+            // the source handler, for a Finished PDU, it is passed to the destination handler.
+            FileDirectiveType::AckPdu => {
+                let acked_directive = FileDirectiveType::try_from(raw_packet[header_len + 1])
+                    .map_err(|_| PduError::InvalidDirectiveType {
+                        found: raw_packet[header_len],
+                        expected: None,
+                    })?;
+                if acked_directive == FileDirectiveType::EofPdu {
+                    PacketTarget::SourceEntity
+                } else if acked_directive == FileDirectiveType::FinishedPdu {
+                    PacketTarget::DestEntity
+                } else {
+                    // TODO: Maybe a better error? This might be confusing..
+                    return Err(PduError::InvalidDirectiveType {
+                        found: raw_packet[header_len + 1],
+                        expected: None,
+                    });
+                }
+            }
+        };
+        Ok(Self {
+            pdu_type: pdu_header.pdu_type(),
+            pdu_directive: Some(directive),
+            target: packet_target,
+            raw_packet,
+        })
+    }
+
+    pub fn pdu_type(&self) -> PduType {
+        self.pdu_type
+    }
+
+    pub fn pdu_directive(&self) -> Option<FileDirectiveType> {
+        self.pdu_directive
+    }
+
+    pub fn target(&self) -> PacketTarget {
+        self.target
+    }
+
+    pub fn raw_packet(&self) -> &[u8] {
+        self.raw_packet
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use spacepackets::cfdp::{
+        lv::Lv,
+        pdu::{
+            eof::EofPdu,
+            file_data::FileDataPdu,
+            metadata::{MetadataGenericParams, MetadataPdu},
+            CommonPduConfig, FileDirectiveType, PduHeader,
+        },
+        PduType,
+    };
+
+    use crate::cfdp::PacketTarget;
+
+    use super::PacketInfo;
+
+    fn generic_pdu_header() -> PduHeader {
+        let pdu_conf = CommonPduConfig::default();
+        PduHeader::new_no_file_data(pdu_conf, 0)
+    }
+
+    #[test]
+    fn test_metadata_pdu_info() {
+        let mut buf: [u8; 128] = [0; 128];
+        let pdu_header = generic_pdu_header();
+        let metadata_params = MetadataGenericParams::default();
+        let src_file_name = "hello.txt";
+        let dest_file_name = "hello-dest.txt";
+        let src_lv = Lv::new_from_str(src_file_name).unwrap();
+        let dest_lv = Lv::new_from_str(dest_file_name).unwrap();
+        let metadata_pdu = MetadataPdu::new(pdu_header, metadata_params, src_lv, dest_lv, None);
+        metadata_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing metadata PDU failed");
+
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        assert_eq!(packet_info.pdu_type(), PduType::FileDirective);
+        assert!(packet_info.pdu_directive().is_some());
+        assert_eq!(
+            packet_info.pdu_directive().unwrap(),
+            FileDirectiveType::MetadataPdu
+        );
+        assert_eq!(packet_info.target(), PacketTarget::DestEntity);
+    }
+
+    #[test]
+    fn test_filedata_pdu_info() {
+        let mut buf: [u8; 128] = [0; 128];
+        let pdu_header = generic_pdu_header();
+        let file_data_pdu = FileDataPdu::new_no_seg_metadata(pdu_header, 0, &[]);
+        file_data_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing file data PDU failed");
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        assert_eq!(packet_info.pdu_type(), PduType::FileData);
+        assert!(packet_info.pdu_directive().is_none());
+        assert_eq!(packet_info.target(), PacketTarget::DestEntity);
+    }
+
+    #[test]
+    fn test_eof_pdu_info() {
+        let mut buf: [u8; 128] = [0; 128];
+        let pdu_header = generic_pdu_header();
+        let eof_pdu = EofPdu::new_no_error(pdu_header, 0, 0);
+        eof_pdu
+            .write_to_bytes(&mut buf)
+            .expect("writing file data PDU failed");
+        let packet_info = PacketInfo::new(&buf).expect("creating packet info failed");
+        assert_eq!(packet_info.pdu_type(), PduType::FileDirective);
+        assert!(packet_info.pdu_directive().is_some());
+        assert_eq!(
+            packet_info.pdu_directive().unwrap(),
+            FileDirectiveType::EofPdu
+        );
+    }
+}

satrs-core/src/cfdp/source.rs

@@ -0,0 +1,15 @@
+#![allow(dead_code)]
+use spacepackets::util::UnsignedByteField;
+
+pub struct SourceHandler {
+    id: UnsignedByteField,
+}
+
+impl SourceHandler {
+    pub fn new(id: impl Into<UnsignedByteField>) -> Self {
+        Self { id: id.into() }
+    }
+}
+
+#[cfg(test)]
+mod tests {}

satrs-core/src/cfdp/user.rs

@@ -0,0 +1,65 @@
+use spacepackets::{
+    cfdp::{
+        pdu::{
+            file_data::RecordContinuationState,
+            finished::{DeliveryCode, FileStatus},
+        },
+        tlv::msg_to_user::MsgToUserTlv,
+        ConditionCode,
+    },
+    util::UnsignedByteField,
+};
+
+use super::TransactionId;
+
+#[derive(Debug, Copy, Clone)]
+pub struct TransactionFinishedParams {
+    pub id: TransactionId,
+    pub condition_code: ConditionCode,
+    pub delivery_code: DeliveryCode,
+    pub file_status: FileStatus,
+}
+
+#[derive(Debug)]
+pub struct MetadataReceivedParams<'src_file, 'dest_file, 'msgs_to_user> {
+    pub id: TransactionId,
+    pub source_id: UnsignedByteField,
+    pub file_size: u64,
+    pub src_file_name: &'src_file str,
+    pub dest_file_name: &'dest_file str,
+    pub msgs_to_user: &'msgs_to_user [MsgToUserTlv<'msgs_to_user>],
+}
+
+#[derive(Debug)]
+pub struct FileSegmentRecvdParams<'seg_meta> {
+    pub id: TransactionId,
+    pub offset: u64,
+    pub length: usize,
+    pub rec_cont_state: Option<RecordContinuationState>,
+    pub segment_metadata: Option<&'seg_meta [u8]>,
+}
+
+pub trait CfdpUser {
+    fn transaction_indication(&mut self, id: &TransactionId);
+    fn eof_sent_indication(&mut self, id: &TransactionId);
+    fn transaction_finished_indication(&mut self, finished_params: &TransactionFinishedParams);
+    fn metadata_recvd_indication(&mut self, md_recvd_params: &MetadataReceivedParams);
+    fn file_segment_recvd_indication(&mut self, segment_recvd_params: &FileSegmentRecvdParams);
+    // TODO: The standard does not strictly specify how the report information looks..
+    fn report_indication(&mut self, id: &TransactionId);
+    fn suspended_indication(&mut self, id: &TransactionId, condition_code: ConditionCode);
+    fn resumed_indication(&mut self, id: &TransactionId, progress: u64);
+    fn fault_indication(
+        &mut self,
+        id: &TransactionId,
+        condition_code: ConditionCode,
+        progress: u64,
+    );
+    fn abandoned_indication(
+        &mut self,
+        id: &TransactionId,
+        condition_code: ConditionCode,
+        progress: u64,
+    );
+    fn eof_recvd_indication(&mut self, id: &TransactionId);
+}

satrs-core/src/executable.rs

@@ -29,7 +29,7 @@ pub trait Executable: Send {
     fn periodic_op(&mut self, op_code: i32) -> Result<OpResult, Self::Error>;
 }
 
-/// This function allows executing one task which implements the [Executable][Executable] trait
+/// This function allows executing one task which implements the [Executable] trait
 ///
 /// # Arguments
 ///
@@ -78,7 +78,7 @@ pub fn exec_sched_single<
 }
 
 /// This function allows executing multiple tasks as long as the tasks implement the
-/// [Executable][Executable] trait
+/// [Executable] trait
 ///
 /// # Arguments
 ///

satrs-core/src/lib.rs

@@ -20,6 +20,7 @@ extern crate downcast_rs;
 #[cfg(any(feature = "std", test))]
 extern crate std;
 
+pub mod cfdp;
 pub mod encoding;
 pub mod error;
 #[cfg(feature = "alloc")]