more complex app runs as well..

Cargo.lock

@@ -90,8 +90,10 @@ checksum = "8a0d04d43504c61aa6c7531f1871dd0d418d91130162063b789da00fd7057a5e"
 dependencies = [
  "android-tzdata",
  "iana-time-zone",
+ "js-sys",
  "num-traits",
  "serde",
+ "wasm-bindgen",
  "windows-targets 0.52.4",
 ]
 
@@ -184,6 +186,12 @@ dependencies = [
  "allocator-api2",
 ]
 
+[[package]]
+name = "heck"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.9"
@@ -232,6 +240,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.153"
@@ -297,12 +311,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
 [[package]]
-name = "ops-sat-sw"
+name = "ops-sat-rs"
 version = "0.1.0"
 dependencies = [
+ "chrono",
  "fern",
+ "lazy_static",
  "log",
  "satrs",
+ "strum",
 ]
 
 [[package]]
@@ -360,6 +377,12 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "80af6f9131f277a45a3fba6ce8e2258037bb0477a67e610d3c1fe046ab31de47"
+
 [[package]]
 name = "satrs"
 version = "0.2.0-rc.0"
@@ -445,6 +468,28 @@ dependencies = [
  "zerocopy",
 ]
 
+[[package]]
+name = "strum"
+version = "0.26.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d8cec3501a5194c432b2b7976db6b7d10ec95c253208b45f83f7136aa985e29"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.26.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6cf59daf282c0a494ba14fd21610a0325f9f90ec9d1231dea26bcb1d696c946"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn 2.0.58",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"

Cargo.toml

@@ -7,7 +7,10 @@ edition = "2021"
 
 [dependencies]
 fern = "0.6"
+chrono = "0.4"
 log = "0.4"
+lazy_static = "1"
+strum = { version = "0.26", features = ["derive"] }
 
 [dependencies.satrs]
 version = "0.2.0-rc.0"

src/ccsds.rs

@@ -0,0 +1,53 @@
+use satrs::pus::ReceivesEcssPusTc;
+use satrs::spacepackets::{CcsdsPacket, SpHeader};
+use satrs::tmtc::{CcsdsPacketHandler, ReceivesCcsdsTc};
+use satrs::ValidatorU16Id;
+use ops_sat_rs::config::components::Apid;
+use ops_sat_rs::config::APID_VALIDATOR;
+
+#[derive(Clone)]
+pub struct CcsdsReceiver<
+    TcSource: ReceivesCcsdsTc<Error = E> + ReceivesEcssPusTc<Error = E> + Clone,
+    E,
+> {
+    pub tc_source: TcSource,
+}
+
+impl<
+        TcSource: ReceivesCcsdsTc<Error = E> + ReceivesEcssPusTc<Error = E> + Clone + 'static,
+        E: 'static,
+    > ValidatorU16Id for CcsdsReceiver<TcSource, E>
+{
+    fn validate(&self, apid: u16) -> bool {
+        APID_VALIDATOR.contains(&apid)
+    }
+}
+
+impl<
+        TcSource: ReceivesCcsdsTc<Error = E> + ReceivesEcssPusTc<Error = E> + Clone + 'static,
+        E: 'static,
+    > CcsdsPacketHandler for CcsdsReceiver<TcSource, E>
+{
+    type Error = E;
+
+    fn handle_packet_with_valid_apid(
+        &mut self,
+        sp_header: &SpHeader,
+        tc_raw: &[u8],
+    ) -> Result<(), Self::Error> {
+        if sp_header.apid() == Apid::Cfdp as u16 {
+        } else {
+            return self.tc_source.pass_ccsds(sp_header, tc_raw);
+        }
+        Ok(())
+    }
+
+    fn handle_packet_with_unknown_apid(
+        &mut self,
+        sp_header: &SpHeader,
+        _tc_raw: &[u8],
+    ) -> Result<(), Self::Error> {
+        log::warn!("unknown APID 0x{:x?} detected", sp_header.apid());
+        Ok(())
+    }
+}

src/config.rs

@@ -0,0 +1,74 @@
+use lazy_static::lazy_static;
+use satrs::spacepackets::{PacketId, PacketType};
+use std::{collections::HashSet, net::Ipv4Addr};
+use strum::IntoEnumIterator;
+
+pub const OBSW_SERVER_ADDR: Ipv4Addr = Ipv4Addr::UNSPECIFIED;
+pub const SERVER_PORT: u16 = 7301;
+
+lazy_static! {
+    pub static ref PACKET_ID_VALIDATOR: HashSet<PacketId> = {
+        let mut set = HashSet::new();
+        for id in components::Apid::iter() {
+            set.insert(PacketId::new(PacketType::Tc, true, id as u16));
+        }
+        set
+    };
+    pub static ref APID_VALIDATOR: HashSet<u16> = {
+        let mut set = HashSet::new();
+        for id in components::Apid::iter() {
+            set.insert(id as u16);
+        }
+        set
+    };
+}
+
+pub mod components {
+    use satrs::request::UniqueApidTargetId;
+    use strum::EnumIter;
+
+    #[derive(Copy, Clone, PartialEq, Eq, EnumIter)]
+    pub enum Apid {
+        Sched = 1,
+        GenericPus = 2,
+        Cfdp = 4,
+    }
+
+    // Component IDs for components with the PUS APID.
+    #[derive(Copy, Clone, PartialEq, Eq)]
+    pub enum PusId {
+        PusEventManagement = 0,
+        PusRouting = 1,
+        PusTest = 2,
+        PusAction = 3,
+        PusMode = 4,
+        PusHk = 5,
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq)]
+    pub enum AcsId {
+        Mgm0 = 0,
+    }
+
+    pub const PUS_ACTION_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, PusId::PusAction as u32);
+    pub const PUS_EVENT_MANAGEMENT: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, 0);
+    pub const PUS_ROUTING_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, PusId::PusRouting as u32);
+    pub const PUS_TEST_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, PusId::PusTest as u32);
+    pub const PUS_MODE_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, PusId::PusMode as u32);
+    pub const PUS_HK_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::GenericPus as u16, PusId::PusHk as u32);
+    pub const PUS_SCHED_SERVICE: UniqueApidTargetId =
+        UniqueApidTargetId::new(Apid::Sched as u16, 0);
+}
+
+pub mod tasks {
+    pub const FREQ_MS_UDP_TMTC: u64 = 200;
+    pub const FREQ_MS_EVENT_HANDLING: u64 = 400;
+    pub const FREQ_MS_AOCS: u64 = 500;
+    pub const FREQ_MS_PUS_STACK: u64 = 200;
+}

src/lib.rs

@@ -0,0 +1,3 @@
+use std::net::Ipv4Addr;
+
+pub mod config;

src/logger.rs

@@ -0,0 +1,17 @@
+pub fn setup_logger() -> Result<(), fern::InitError> {
+    fern::Dispatch::new()
+        .format(|out, message, record| {
+            out.finish(format_args!(
+                "{}[{}][{}] {}",
+                chrono::Local::now().format("[%Y-%m-%d][%H:%M:%S]"),
+                std::thread::current().name().expect("unnamed_thread"),
+                record.level(),
+                message
+            ))
+        })
+        .level(log::LevelFilter::Debug)
+        .chain(std::io::stdout())
+        .chain(fern::log_file("output.log")?)
+        .apply()?;
+    Ok(())
+}

src/main.rs

@@ -1,7 +1,95 @@
-fn main() {
+use std::{
-    println!("OPSSAT Rust experiment OBSW");
+    net::{IpAddr, SocketAddr},
+    sync::mpsc,
+    thread,
+    time::Duration,
+};
 
-    loop {
+use log::info;
-        std::thread::sleep(std::time::Duration::from_millis(500));
+use ops_sat_rs::config::{
-    }
+    tasks::FREQ_MS_UDP_TMTC, OBSW_SERVER_ADDR, PACKET_ID_VALIDATOR, SERVER_PORT,
+};
+use satrs::{
+    hal::std::{tcp_server::ServerConfig, udp_server::UdpTcServer},
+    tmtc::CcsdsDistributor,
+};
+
+use crate::{
+    ccsds::CcsdsReceiver,
+    logger::setup_logger,
+    tcp::{SyncTcpTmSource, TcpTask},
+    tmtc::PusTcSourceProviderDynamic,
+    udp::{DynamicUdpTmHandler, UdpTmtcServer},
+};
+
+mod ccsds;
+mod logger;
+mod tcp;
+mod tmtc;
+mod udp;
+
+fn main() {
+    setup_logger().expect("setting up logging with fern failed");
+    println!("OPS-SAT Rust experiment OBSW");
+
+    let (tc_source_tx, tc_source_rx) = mpsc::channel();
+    let (tm_server_tx, tm_server_rx) = mpsc::channel();
+
+    let tc_source = PusTcSourceProviderDynamic(tc_source_tx);
+
+    let ccsds_receiver = CcsdsReceiver { tc_source };
+
+    let sock_addr = SocketAddr::new(IpAddr::V4(OBSW_SERVER_ADDR), SERVER_PORT);
+    let udp_ccsds_distributor = CcsdsDistributor::new(ccsds_receiver.clone());
+    let udp_tc_server = UdpTcServer::new(sock_addr, 2048, Box::new(udp_ccsds_distributor))
+        .expect("creating UDP TMTC server failed");
+
+    let mut udp_tmtc_server = UdpTmtcServer {
+        udp_tc_server,
+        tm_handler: DynamicUdpTmHandler {
+            tm_rx: tm_server_rx,
+        },
+    };
+
+    let tcp_ccsds_distributor = CcsdsDistributor::new(ccsds_receiver);
+    let tcp_server_cfg = ServerConfig::new(sock_addr, Duration::from_millis(400), 4096, 8192);
+    let sync_tm_tcp_source = SyncTcpTmSource::new(200);
+    let mut tcp_server = TcpTask::new(
+        tcp_server_cfg,
+        sync_tm_tcp_source.clone(),
+        tcp_ccsds_distributor,
+        PACKET_ID_VALIDATOR.clone(),
+    )
+    .expect("tcp server creation failed");
+
+    info!("Starting TMTC and UDP task");
+    let jh_udp_tmtc = thread::Builder::new()
+        .name("TMTC and UDP".to_string())
+        .spawn(move || {
+            info!("Running UDP server on port {SERVER_PORT}");
+            loop {
+                udp_tmtc_server.periodic_operation();
+                // tmtc_task.periodic_operation();
+                thread::sleep(Duration::from_millis(FREQ_MS_UDP_TMTC));
+            }
+        })
+        .unwrap();
+
+    info!("Starting TCP task");
+    let jh_tcp = thread::Builder::new()
+        .name("TCP".to_string())
+        .spawn(move || {
+            info!("Running TCP server on port {SERVER_PORT}");
+            loop {
+                tcp_server.periodic_operation();
+            }
+        })
+        .unwrap();
+
+    jh_udp_tmtc
+        .join()
+        .expect("Joining UDP TMTC server thread failed");
+    jh_tcp
+        .join()
+        .expect("Joining TCP TMTC server thread failed");
 }

src/tcp.rs

@@ -0,0 +1,127 @@
+use std::{
+    collections::{HashSet, VecDeque},
+    sync::{Arc, Mutex},
+};
+
+use log::{info, warn};
+use satrs::{
+    hal::std::tcp_server::{ServerConfig, TcpSpacepacketsServer},
+    pus::ReceivesEcssPusTc,
+    spacepackets::PacketId,
+    tmtc::{CcsdsDistributor, CcsdsError, ReceivesCcsdsTc, TmPacketSourceCore},
+};
+
+use crate::ccsds::CcsdsReceiver;
+
+#[derive(Default, Clone)]
+pub struct SyncTcpTmSource {
+    tm_queue: Arc<Mutex<VecDeque<Vec<u8>>>>,
+    max_packets_stored: usize,
+    pub silent_packet_overwrite: bool,
+}
+
+impl SyncTcpTmSource {
+    pub fn new(max_packets_stored: usize) -> Self {
+        Self {
+            tm_queue: Arc::default(),
+            max_packets_stored,
+            silent_packet_overwrite: true,
+        }
+    }
+
+    pub fn add_tm(&mut self, tm: &[u8]) {
+        let mut tm_queue = self.tm_queue.lock().expect("locking tm queue failec");
+        if tm_queue.len() > self.max_packets_stored {
+            if !self.silent_packet_overwrite {
+                warn!("TPC TM source is full, deleting oldest packet");
+            }
+            tm_queue.pop_front();
+        }
+        tm_queue.push_back(tm.to_vec());
+    }
+}
+
+impl TmPacketSourceCore for SyncTcpTmSource {
+    type Error = ();
+
+    fn retrieve_packet(&mut self, buffer: &mut [u8]) -> Result<usize, Self::Error> {
+        let mut tm_queue = self.tm_queue.lock().expect("locking tm queue failed");
+        if !tm_queue.is_empty() {
+            let next_vec = tm_queue.front().unwrap();
+            if buffer.len() < next_vec.len() {
+                panic!(
+                    "provided buffer too small, must be at least {} bytes",
+                    next_vec.len()
+                );
+            }
+            let next_vec = tm_queue.pop_front().unwrap();
+            buffer[0..next_vec.len()].copy_from_slice(&next_vec);
+            if next_vec.len() > 9 {
+                let service = next_vec[7];
+                let subservice = next_vec[8];
+                info!("Sending PUS TM[{service},{subservice}]")
+            } else {
+                info!("Sending PUS TM");
+            }
+            return Ok(next_vec.len());
+        }
+        Ok(0)
+    }
+}
+
+pub type TcpServerType<TcSource, MpscErrorType> = TcpSpacepacketsServer<
+    (),
+    CcsdsError<MpscErrorType>,
+    SyncTcpTmSource,
+    CcsdsDistributor<CcsdsReceiver<TcSource, MpscErrorType>, MpscErrorType>,
+    HashSet<PacketId>,
+>;
+
+pub struct TcpTask<
+    TcSource: ReceivesCcsdsTc<Error = MpscErrorType>
+        + ReceivesEcssPusTc<Error = MpscErrorType>
+        + Clone
+        + Send
+        + 'static,
+    MpscErrorType: 'static,
+> {
+    server: TcpServerType<TcSource, MpscErrorType>,
+}
+
+impl<
+        TcSource: ReceivesCcsdsTc<Error = MpscErrorType>
+            + ReceivesEcssPusTc<Error = MpscErrorType>
+            + Clone
+            + Send
+            + 'static,
+        MpscErrorType: 'static + core::fmt::Debug,
+    > TcpTask<TcSource, MpscErrorType>
+{
+    pub fn new(
+        cfg: ServerConfig,
+        tm_source: SyncTcpTmSource,
+        tc_receiver: CcsdsDistributor<CcsdsReceiver<TcSource, MpscErrorType>, MpscErrorType>,
+        packet_id_lookup: HashSet<PacketId>,
+    ) -> Result<Self, std::io::Error> {
+        Ok(Self {
+            server: TcpSpacepacketsServer::new(cfg, tm_source, tc_receiver, packet_id_lookup)?,
+        })
+    }
+
+    pub fn periodic_operation(&mut self) {
+        loop {
+            let result = self.server.handle_next_connection();
+            match result {
+                Ok(conn_result) => {
+                    info!(
+                        "Served {} TMs and {} TCs for client {:?}",
+                        conn_result.num_sent_tms, conn_result.num_received_tcs, conn_result.addr
+                    );
+                }
+                Err(e) => {
+                    warn!("TCP server error: {e:?}");
+                }
+            }
+        }
+    }
+}

src/tmtc.rs

@@ -0,0 +1,81 @@
+use satrs::{
+    pus::ReceivesEcssPusTc,
+    spacepackets::{ecss::tc::PusTcReader, SpHeader},
+    tmtc::ReceivesCcsdsTc,
+};
+use std::sync::mpsc::{self, SendError, Sender, TryRecvError};
+
+// Newtype, can not implement necessary traits on MPSC sender directly because of orphan rules.
+#[derive(Clone)]
+pub struct PusTcSourceProviderDynamic(pub Sender<Vec<u8>>);
+
+impl ReceivesEcssPusTc for PusTcSourceProviderDynamic {
+    type Error = SendError<Vec<u8>>;
+
+    fn pass_pus_tc(&mut self, _: &SpHeader, pus_tc: &PusTcReader) -> Result<(), Self::Error> {
+        self.0.send(pus_tc.raw_data().to_vec())?;
+        Ok(())
+    }
+}
+
+impl ReceivesCcsdsTc for PusTcSourceProviderDynamic {
+    type Error = mpsc::SendError<Vec<u8>>;
+
+    fn pass_ccsds(&mut self, _: &SpHeader, tc_raw: &[u8]) -> Result<(), Self::Error> {
+        self.0.send(tc_raw.to_vec())?;
+        Ok(())
+    }
+}
+
+// TC source components where the heap is the backing memory of the received telecommands.
+pub struct TcSourceTaskDynamic {
+    pub tc_receiver: mpsc::Receiver<Vec<u8>>,
+    // pus_receiver: PusReceiver<MpscTmAsVecSender>,
+}
+
+impl TcSourceTaskDynamic {
+    pub fn new(
+        tc_receiver: mpsc::Receiver<Vec<u8>>,
+        // pus_receiver: PusReceiver<MpscTmAsVecSender>,
+    ) -> Self {
+        Self {
+            tc_receiver,
+            // pus_receiver,
+        }
+    }
+
+    pub fn periodic_operation(&mut self) {
+        self.poll_tc();
+    }
+
+    pub fn poll_tc(&mut self) -> bool {
+        match self.tc_receiver.try_recv() {
+            Ok(tc) => match PusTcReader::new(&tc) {
+                Ok((pus_tc, _)) => {
+                    /*
+                    self.pus_receiver
+                        .handle_tc_packet(
+                            satrs::pus::TcInMemory::Vec(tc.clone()),
+                            pus_tc.service(),
+                            &pus_tc,
+                        )
+                        .ok();
+                    */
+                    true
+                }
+                Err(e) => {
+                    log::warn!("error creating PUS TC from raw data: {e}");
+                    log::warn!("raw data: {:x?}", tc);
+                    true
+                }
+            },
+            Err(e) => match e {
+                TryRecvError::Empty => false,
+                TryRecvError::Disconnected => {
+                    log::warn!("tmtc thread: sender disconnected");
+                    false
+                }
+            },
+        }
+    }
+}

src/udp.rs

@@ -0,0 +1,185 @@
+use std::net::{SocketAddr, UdpSocket};
+use std::sync::mpsc;
+
+use log::{info, warn};
+use satrs::pus::{PusTmAsVec, PusTmInPool};
+use satrs::{
+    hal::std::udp_server::{ReceiveResult, UdpTcServer},
+    pool::{PoolProviderWithGuards, SharedStaticMemoryPool},
+    tmtc::CcsdsError,
+};
+
+pub trait UdpTmHandler {
+    fn send_tm_to_udp_client(&mut self, socket: &UdpSocket, recv_addr: &SocketAddr);
+}
+
+pub struct DynamicUdpTmHandler {
+    pub tm_rx: mpsc::Receiver<PusTmAsVec>,
+}
+
+impl UdpTmHandler for DynamicUdpTmHandler {
+    fn send_tm_to_udp_client(&mut self, socket: &UdpSocket, recv_addr: &SocketAddr) {
+        while let Ok(tm) = self.tm_rx.try_recv() {
+            if tm.packet.len() > 9 {
+                let service = tm.packet[7];
+                let subservice = tm.packet[8];
+                info!("Sending PUS TM[{service},{subservice}]")
+            } else {
+                info!("Sending PUS TM");
+            }
+            let result = socket.send_to(&tm.packet, recv_addr);
+            if let Err(e) = result {
+                warn!("Sending TM with UDP socket failed: {e}")
+            }
+        }
+    }
+}
+
+pub struct UdpTmtcServer<TmHandler: UdpTmHandler, SendError> {
+    pub udp_tc_server: UdpTcServer<CcsdsError<SendError>>,
+    pub tm_handler: TmHandler,
+}
+
+impl<TmHandler: UdpTmHandler, SendError: core::fmt::Debug + 'static>
+    UdpTmtcServer<TmHandler, SendError>
+{
+    pub fn periodic_operation(&mut self) {
+        while self.poll_tc_server() {}
+        if let Some(recv_addr) = self.udp_tc_server.last_sender() {
+            self.tm_handler
+                .send_tm_to_udp_client(&self.udp_tc_server.socket, &recv_addr);
+        }
+    }
+
+    fn poll_tc_server(&mut self) -> bool {
+        match self.udp_tc_server.try_recv_tc() {
+            Ok(_) => true,
+            Err(e) => match e {
+                ReceiveResult::ReceiverError(e) => match e {
+                    CcsdsError::ByteConversionError(e) => {
+                        warn!("packet error: {e:?}");
+                        true
+                    }
+                    CcsdsError::CustomError(e) => {
+                        warn!("mpsc custom error {e:?}");
+                        true
+                    }
+                },
+                ReceiveResult::IoError(e) => {
+                    warn!("IO error {e}");
+                    false
+                }
+                ReceiveResult::NothingReceived => false,
+            },
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{
+        collections::VecDeque,
+        net::IpAddr,
+        sync::{Arc, Mutex},
+    };
+
+    use satrs::{
+        spacepackets::{
+            ecss::{tc::PusTcCreator, WritablePusPacket},
+            SpHeader,
+        },
+        tmtc::ReceivesTcCore,
+    };
+    use satrs_example::config::{components, OBSW_SERVER_ADDR};
+
+    use super::*;
+
+    #[derive(Default, Debug, Clone)]
+    pub struct TestReceiver {
+        tc_vec: Arc<Mutex<VecDeque<Vec<u8>>>>,
+    }
+
+    impl ReceivesTcCore for TestReceiver {
+        type Error = CcsdsError<()>;
+        fn pass_tc(&mut self, tc_raw: &[u8]) -> Result<(), Self::Error> {
+            self.tc_vec.lock().unwrap().push_back(tc_raw.to_vec());
+            Ok(())
+        }
+    }
+
+    #[derive(Default, Debug, Clone)]
+    pub struct TestTmHandler {
+        addrs_to_send_to: Arc<Mutex<VecDeque<SocketAddr>>>,
+    }
+
+    impl UdpTmHandler for TestTmHandler {
+        fn send_tm_to_udp_client(&mut self, _socket: &UdpSocket, recv_addr: &SocketAddr) {
+            self.addrs_to_send_to.lock().unwrap().push_back(*recv_addr);
+        }
+    }
+
+    #[test]
+    fn test_basic() {
+        let sock_addr = SocketAddr::new(IpAddr::V4(OBSW_SERVER_ADDR), 0);
+        let test_receiver = TestReceiver::default();
+        let tc_queue = test_receiver.tc_vec.clone();
+        let udp_tc_server = UdpTcServer::new(sock_addr, 2048, Box::new(test_receiver)).unwrap();
+        let tm_handler = TestTmHandler::default();
+        let tm_handler_calls = tm_handler.addrs_to_send_to.clone();
+        let mut udp_dyn_server = UdpTmtcServer {
+            udp_tc_server,
+            tm_handler,
+        };
+        udp_dyn_server.periodic_operation();
+        assert!(tc_queue.lock().unwrap().is_empty());
+        assert!(tm_handler_calls.lock().unwrap().is_empty());
+    }
+
+    #[test]
+    fn test_transactions() {
+        let sock_addr = SocketAddr::new(IpAddr::V4(OBSW_SERVER_ADDR), 0);
+        let test_receiver = TestReceiver::default();
+        let tc_queue = test_receiver.tc_vec.clone();
+        let udp_tc_server = UdpTcServer::new(sock_addr, 2048, Box::new(test_receiver)).unwrap();
+        let server_addr = udp_tc_server.socket.local_addr().unwrap();
+        let tm_handler = TestTmHandler::default();
+        let tm_handler_calls = tm_handler.addrs_to_send_to.clone();
+        let mut udp_dyn_server = UdpTmtcServer {
+            udp_tc_server,
+            tm_handler,
+        };
+        let sph = SpHeader::new_for_unseg_tc(components::Apid::GenericPus as u16, 0, 0);
+        let ping_tc = PusTcCreator::new_simple(sph, 17, 1, &[], true)
+            .to_vec()
+            .unwrap();
+        let client = UdpSocket::bind("127.0.0.1:0").expect("Connecting to UDP server failed");
+        let client_addr = client.local_addr().unwrap();
+        client.connect(server_addr).unwrap();
+        client.send(&ping_tc).unwrap();
+        udp_dyn_server.periodic_operation();
+        {
+            let mut tc_queue = tc_queue.lock().unwrap();
+            assert!(!tc_queue.is_empty());
+            let received_tc = tc_queue.pop_front().unwrap();
+            assert_eq!(received_tc, ping_tc);
+        }
+
+        {
+            let mut tm_handler_calls = tm_handler_calls.lock().unwrap();
+            assert!(!tm_handler_calls.is_empty());
+            assert_eq!(tm_handler_calls.len(), 1);
+            let received_addr = tm_handler_calls.pop_front().unwrap();
+            assert_eq!(received_addr, client_addr);
+        }
+        udp_dyn_server.periodic_operation();
+        assert!(tc_queue.lock().unwrap().is_empty());
+        // Still tries to send to the same client.
+        {
+            let mut tm_handler_calls = tm_handler_calls.lock().unwrap();
+            assert!(!tm_handler_calls.is_empty());
+            assert_eq!(tm_handler_calls.len(), 1);
+            let received_addr = tm_handler_calls.pop_front().unwrap();
+            assert_eq!(received_addr, client_addr);
+        }
+    }
+}