try to fix issue ANSSI-FR#3

src/receive/decoding.rs

@@ -1,10 +1,11 @@
 //! Worker that decodes RaptorQ packets into protocol messages
 
-use std::{cmp::Ordering, thread::yield_now};
-
 use crate::{protocol, receive};
 
-pub(crate) fn start<F>(receiver: &receive::Receiver<F>) -> Result<(), receive::Error> {
+pub(crate) fn start<F>(
+    receiver: &receive::Receiver<F>,
+    nb_decoding_threads: u8,
+) -> Result<(), receive::Error> {
     let encoding_block_size = receiver.object_transmission_info.transfer_length();
 
     loop {
@@ -23,37 +24,34 @@ pub(crate) fn start<F>(receiver: &receive::Receiver<F>) -> Result<(), receive::E
 
         match decoder.decode(packets) {
             None => {
-                log::warn!("lost block {block_id}");
+                log::error!("lost block {block_id}, synchronization lost");
                 continue;
             }
             Some(block) => {
-                log::trace!("block {} decoded with {} bytes!", block_id, block.len());
+                log::trace!("block {block_id} decoded with {} bytes!", block.len());
 
-                let mut retry_cnt = 0;
+                let mut retried = 0;
 
                 loop {
                     let mut to_receive = receiver.block_to_receive.lock().expect("acquire lock");
-                    match block_id.cmp(&to_receive) {
-                        Ordering::Equal => {
-                            receiver
-                                .to_dispatch
-                                .send(protocol::Message::deserialize(block))?;
-                            *to_receive = to_receive.wrapping_add(1);
-                            break;
-                        }
-                        Ordering::Greater => {
-                            // Thread is too late, drop the packet and kill the current job
-                            log::warn!("Dropping the packet {block_id}");
+
+                    if *to_receive == block_id {
+                        // The decoded block is the expected one, dispatching it
+                        receiver
+                            .to_dispatch
+                            .send(protocol::Message::deserialize(block))?;
+                        *to_receive = to_receive.wrapping_add(1);
+                        break;
+                    } else {
+                        // The decoded block is not the expected one
+                        // Retrying until all decoding threads had one chance to dispatch their block
+                        if nb_decoding_threads < retried {
+                            // All decoding threads should have had one chance to dispatch their block
+                            log::warn!("dropping block {block_id} after trying to dispatch it {retried} times");
+
                             break;
                         }
-                        Ordering::Less => {
-                            if retry_cnt < 10 {
-                                retry_cnt += 1;
-                                yield_now();
-                            } else {
-                                break;
-                            }
-                        }
+                        retried += 1;
                     }
                 }
             }

src/receive/mod.rs

@@ -275,7 +275,9 @@ where
         for i in 0..self.config.nb_decoding_threads {
             thread::Builder::new()
                 .name(format!("decoding_{i}"))
-                .spawn_scoped(scope, || decoding::start(self))?;
+                .spawn_scoped(scope, || {
+                    decoding::start(self, self.config.nb_decoding_threads)
+                })?;
         }
 
         thread::Builder::new()