satrs-core/src/hal/std/tcp_server.rs

@@ -1,6 +1,7 @@
 //! Generic TCP TMTC servers with different TMTC format flavours.
 use alloc::vec;
 use alloc::{boxed::Box, vec::Vec};
+use core::time::Duration;
 use socket2::{Domain, Socket, Type};
 use std::net::SocketAddr;
 use std::net::TcpListener;
@@ -34,6 +35,7 @@ pub struct ConnectionResult {
 
 pub(crate) struct TcpTmtcServerBase<TcError, TmError> {
     pub(crate) listener: TcpListener,
+    pub(crate) inner_loop_delay: Duration,
     pub(crate) tm_source: Box<dyn TmPacketSource<Error = TmError> + Send>,
     pub(crate) tm_buffer: Vec<u8>,
     pub(crate) tc_receiver: Box<dyn ReceivesTc<Error = TcError> + Send>,
@@ -43,6 +45,7 @@ pub(crate) struct TcpTmtcServerBase<TcError, TmError> {
 impl<TcError, TmError> TcpTmtcServerBase<TcError, TmError> {
     pub(crate) fn new(
         addr: &SocketAddr,
+        inner_loop_delay: Duration,
         reuse_addr: bool,
         reuse_port: bool,
         tm_buffer_size: usize,
@@ -59,6 +62,7 @@ impl<TcError, TmError> TcpTmtcServerBase<TcError, TmError> {
         socket.listen(128)?;
         Ok(Self {
             listener: socket.into(),
+            inner_loop_delay,
             tm_source,
             tm_buffer: vec![0; tm_buffer_size],
             tc_receiver,

satrs-core/src/hal/std/tcp_with_cobs_server.rs

@@ -3,10 +3,14 @@ use alloc::vec;
 use cobs::decode_in_place;
 use cobs::encode;
 use cobs::max_encoding_length;
+use core::time::Duration;
 use std::io::Read;
 use std::io::Write;
 use std::net::SocketAddr;
 use std::net::TcpListener;
+use std::net::TcpStream;
+use std::println;
+use std::thread;
 use std::vec::Vec;
 
 use crate::hal::std::tcp_server::TcpTmtcServerBase;
@@ -16,6 +20,58 @@ use crate::tmtc::TmPacketSource;
 use super::tcp_server::ConnectionResult;
 use super::tcp_server::TcpTmtcError;
 
+/// TCP configuration struct.
+///
+/// ## Parameters
+///
+/// * `addr` - Address of the TCP server.
+/// * `inner_loop_delay` - If a client connects for a longer period, but no TC is received or
+///     no TM needs to be sent, the TCP server will delay for the specified amount of time
+///     to reduce CPU load.
+/// * `tm_buffer_size` - Size of the TM buffer used to read TM from the [TmPacketSource] and
+///     encoding of that data. This buffer should at large enough to hold the maximum expected
+///     TM size in addition to the COBS encoding overhead. You can use
+///     [cobs::max_encoding_length] to calculate this size.
+/// * `tc_buffer_size` - Size of the TC buffer used to read encoded telecommands sent from
+///     the client. It is recommended to make this buffer larger to allow reading multiple
+///     consecutive packets as well, for example by using 4096 or 8192 byte. The buffer should
+///     at the very least be large enough to hold the maximum expected telecommand size in
+///     addition to its COBS encoding overhead. You can use [cobs::max_encoding_length] to
+///     calculate this size.
+/// * `reuse_addr` - Can be used to set the `SO_REUSEADDR` option on the raw socket. This is
+///     especially useful if the address and port are static for the server. Set to false by
+///     default.
+/// * `reuse_port` - Can be used to set the `SO_REUSEPORT` option on the raw socket. This is
+///     especially useful if the address and port are static for the server. Set to false by
+///     default.
+#[derive(Debug, Copy, Clone)]
+pub struct ServerConfig {
+    pub addr: SocketAddr,
+    pub inner_loop_delay: Duration,
+    pub tm_buffer_size: usize,
+    pub tc_buffer_size: usize,
+    pub reuse_addr: bool,
+    pub reuse_port: bool,
+}
+
+impl ServerConfig {
+    pub fn new(
+        addr: SocketAddr,
+        inner_loop_delay: Duration,
+        tm_buffer_size: usize,
+        tc_buffer_size: usize,
+    ) -> Self {
+        Self {
+            addr,
+            inner_loop_delay,
+            tm_buffer_size,
+            tc_buffer_size,
+            reuse_addr: false,
+            reuse_port: false,
+        }
+    }
+}
+
 /// TCP TMTC server implementation for exchange of generic TMTC packets which are framed with the
 /// [COBS protocol](https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing).
 ///
@@ -43,45 +99,27 @@ impl<TcError: 'static, TmError: 'static> TcpTmtcInCobsServer<TcError, TmError> {
     ///
     /// ## Parameter
     ///
-    /// * `addr` - Address of the TCP server.
-    /// * `reuse_addr` - Can be used to set the `SO_REUSEADDR` option on the raw socket. This is
-    ///     especially useful if the address and port are static for the server.
-    /// * `reuse_port` - Can be used to set the `SO_REUSEPORT` option on the raw socket. This is
-    ///     especially useful if the address and port are static for the server.
-    /// * `tm_buffer_size` - Size of the TM buffer used to read TM from the [TmPacketSource] and
-    ///     encoding of that data. This buffer should at large enough to hold the maximum expected
-    ///     TM size in addition to the COBS encoding overhead. You can use
-    ///     [cobs::max_encoding_length] to calculate this size.
     /// * `tm_source` - Generic TM source used by the server to pull telemetry packets which are
     ///     then sent back to the client.
-    /// * `tc_buffer_size` - Size of the TC buffer used to read encoded telecommands sent from
-    ///     the client. It is recommended to make this buffer larger to allow reading multiple
-    ///     consecutive packets as well, for example by using 4096 or 8192 byte. The buffer should
-    ///     at the very least be large enough to hold the maximum expected telecommand size in
-    ///     addition to its COBS encoding overhead. You can use [cobs::max_encoding_length] to
-    ///     calculate this size.
     /// * `tc_receiver` - Any received telecommand which was decoded successfully will be forwarded
     ///     to this TC receiver.
     pub fn new(
-        addr: &SocketAddr,
+        cfg: ServerConfig,
-        reuse_addr: bool,
-        reuse_port: bool,
-        tm_buffer_size: usize,
         tm_source: Box<dyn TmPacketSource<Error = TmError> + Send>,
-        tc_buffer_size: usize,
         tc_receiver: Box<dyn ReceivesTc<Error = TcError> + Send>,
     ) -> Result<Self, std::io::Error> {
         Ok(Self {
             base: TcpTmtcServerBase::new(
-                addr,
+                &cfg.addr,
-                reuse_addr,
+                cfg.inner_loop_delay,
-                reuse_port,
+                cfg.reuse_addr,
-                tm_buffer_size,
+                cfg.reuse_port,
+                cfg.tm_buffer_size,
                 tm_source,
-                tc_buffer_size,
+                cfg.tc_buffer_size,
                 tc_receiver,
             )?,
-            tm_encoding_buffer: vec![0; max_encoding_length(tc_buffer_size)],
+            tm_encoding_buffer: vec![0; max_encoding_length(cfg.tc_buffer_size)],
         })
     }
 
@@ -112,35 +150,85 @@ impl<TcError: 'static, TmError: 'static> TcpTmtcInCobsServer<TcError, TmError> {
         let mut current_write_idx;
         let mut next_write_idx = 0;
         let (mut stream, addr) = self.base.listener.accept()?;
+        stream.set_nonblocking(true)?;
         connection_result.addr = Some(addr);
         current_write_idx = next_write_idx;
-        next_write_idx = 0;
         loop {
-            let read_len = stream.read(&mut self.base.tc_buffer[current_write_idx..])?;
+            let read_result = stream.read(&mut self.base.tc_buffer[current_write_idx..]);
-            if read_len > 0 {
+            match read_result {
-                current_write_idx += read_len;
+                Ok(0) => {
-                if current_write_idx == self.base.tc_buffer.capacity() {
+                    // Connection closed by client. If any TC was read, parse for complete packets.
-                    // Reader vec full, need to parse for packets.
+                    // After that, break the outer loop.
-                    connection_result.num_received_tcs += parse_buffer_for_cobs_encoded_packets(
+                    if current_write_idx > 0 {
-                        &mut self.base.tc_buffer[..current_write_idx],
+                        self.handle_tc_parsing(
-                        self.base.tc_receiver.as_mut(),
+                            &mut connection_result,
+                            current_write_idx,
                             &mut next_write_idx,
-                    )
+                        )?;
-                    .map_err(|e| TcpTmtcError::TcError(e))?;
-                    current_write_idx = next_write_idx;
-                }
-                continue;
                     }
                     break;
                 }
-        if current_write_idx > 0 {
+                Ok(read_len) => {
-            connection_result.num_received_tcs += parse_buffer_for_cobs_encoded_packets(
+                    current_write_idx += read_len;
+                    // TC buffer is full, we must parse for complete packets now.
+                    if current_write_idx == self.base.tc_buffer.capacity() {
+                        self.handle_tc_parsing(
+                            &mut connection_result,
+                            current_write_idx,
+                            &mut next_write_idx,
+                        )?;
+                        current_write_idx = next_write_idx;
+                    }
+                }
+                Err(e) => match e.kind() {
+                    // As per [TcpStream::set_read_timeout] documentation, this should work for
+                    // both UNIX and Windows.
+                    std::io::ErrorKind::WouldBlock | std::io::ErrorKind::TimedOut => {
+                        println!("should be here..");
+                        self.handle_tc_parsing(
+                            &mut connection_result,
+                            current_write_idx,
+                            &mut next_write_idx,
+                        )?;
+                        current_write_idx = next_write_idx;
+                        if !self.handle_tm_sending(&mut connection_result, &mut stream)? {
+                            // No TC read, no TM was sent, but the client has not disconnected.
+                            // Perform an inner delay to avoid burning CPU time.
+                            thread::sleep(self.base.inner_loop_delay);
+                        }
+                    }
+                    _ => {
+                        return Err(TcpTmtcError::Io(e));
+                    }
+                },
+            }
+        }
+        self.handle_tm_sending(&mut connection_result, &mut stream)?;
+        Ok(connection_result)
+    }
+
+    fn handle_tc_parsing(
+        &mut self,
+        conn_result: &mut ConnectionResult,
+        current_write_idx: usize,
+        next_write_idx: &mut usize,
+    ) -> Result<(), TcpTmtcError<TmError, TcError>> {
+        // Reader vec full, need to parse for packets.
+        conn_result.num_received_tcs += parse_buffer_for_cobs_encoded_packets(
             &mut self.base.tc_buffer[..current_write_idx],
             self.base.tc_receiver.as_mut(),
-                &mut next_write_idx,
+            next_write_idx,
         )
         .map_err(|e| TcpTmtcError::TcError(e))?;
+        Ok(())
     }
+
+    fn handle_tm_sending(
+        &mut self,
+        conn_result: &mut ConnectionResult,
+        stream: &mut TcpStream,
+    ) -> Result<bool, TcpTmtcError<TmError, TcError>> {
+        let mut tm_was_sent = false;
         loop {
             // Write TM until TM source is exhausted. For now, there is no limit for the amount
             // of TM written this way.
@@ -149,10 +237,12 @@ impl<TcError: 'static, TmError: 'static> TcpTmtcInCobsServer<TcError, TmError> {
                 .tm_source
                 .retrieve_packet(&mut self.base.tm_buffer)
                 .map_err(|e| TcpTmtcError::TmError(e))?;
+
             if read_tm_len == 0 {
-                break;
+                return Ok(tm_was_sent);
             }
-            connection_result.num_sent_tms += 1;
+            tm_was_sent = true;
+            conn_result.num_sent_tms += 1;
 
             // Encode into COBS and sent to client.
             let mut current_idx = 0;
@@ -166,7 +256,6 @@ impl<TcError: 'static, TmError: 'static> TcpTmtcInCobsServer<TcError, TmError> {
             current_idx += 1;
             stream.write_all(&self.tm_encoding_buffer[..current_idx])?;
         }
-        Ok(connection_result)
     }
 }
 
@@ -239,7 +328,7 @@ mod tests {
     use alloc::{boxed::Box, collections::VecDeque, sync::Arc, vec::Vec};
     use cobs::encode;
 
-    use super::{parse_buffer_for_cobs_encoded_packets, TcpTmtcInCobsServer};
+    use super::{parse_buffer_for_cobs_encoded_packets, ServerConfig, TcpTmtcInCobsServer};
 
     const SIMPLE_PACKET: [u8; 5] = [1, 2, 3, 4, 5];
     const INVERTED_PACKET: [u8; 5] = [5, 4, 3, 2, 1];
@@ -476,12 +565,8 @@ mod tests {
         tm_source: SyncTmSource,
     ) -> TcpTmtcInCobsServer<(), ()> {
         TcpTmtcInCobsServer::new(
-            addr,
+            ServerConfig::new(*addr, Duration::from_millis(2), 1024, 1024),
-            false,
-            false,
-            1024,
             Box::new(tm_source),
-            1024,
             Box::new(tc_receiver.clone()),
         )
         .expect("TCP server generation failed")