Fix issue ANSSI-FR#3: limit block dispatch retries

src/receive/decoding.rs

@@ -2,7 +2,10 @@
 
 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 {
@@ -21,20 +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 retried = 0;
 
                 loop {
                     let mut to_receive = receiver.block_to_receive.lock().expect("acquire lock");
+
                     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;
+                        }
+                        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()