do some refactor

1. Route must impl PeerPacketFilter trait.
2. Use postcard lib to serial msg instead of bincode.
3. Fix cycle ref in peer_mgr & peer_rpc

easytier-core/src/peers/mod.rs

@@ -13,3 +13,26 @@ pub mod foreign_network_manager;
 
 #[cfg(test)]
 pub mod tests;
+
+use tokio_util::bytes::{Bytes, BytesMut};
+
+#[async_trait::async_trait]
+#[auto_impl::auto_impl(Arc)]
+pub trait PeerPacketFilter {
+    async fn try_process_packet_from_peer(
+        &self,
+        _packet: &packet::ArchivedPacket,
+        _data: &Bytes,
+    ) -> Option<()> {
+        None
+    }
+}
+
+#[async_trait::async_trait]
+#[auto_impl::auto_impl(Arc)]
+pub trait NicPacketFilter {
+    async fn try_process_packet_from_nic(&self, data: BytesMut) -> BytesMut;
+}
+
+type BoxPeerPacketFilter = Box<dyn PeerPacketFilter + Send + Sync>;
+type BoxNicPacketFilter = Box<dyn NicPacketFilter + Send + Sync>;