diff --git a/satrs-core/src/cfdp/dest.rs b/satrs-core/src/cfdp/dest.rs
index 13e5cbe..09e21fa 100644
--- a/satrs-core/src/cfdp/dest.rs
+++ b/satrs-core/src/cfdp/dest.rs
@@ -1,13 +1,25 @@
-use super::{TransactionStep, State};
+use spacepackets::cfdp::{pdu::FileDirectiveType, PduType};
+
+use super::{State, TransactionStep};
 
 pub struct DestinationHandler {
     step: TransactionStep,
-    state: State
+    state: State,
 }
 
 impl DestinationHandler {
-
-    pub fn state_machine() {}
-
-
+    pub fn insert_packet(
+        &mut self,
+        pdu_type: PduType,
+        pdu_directive: Option<FileDirectiveType>,
+        raw_packet: &[u8],
+    ) {
+    }
+    pub fn state_machine(&mut self) {
+        match self.state {
+            State::Idle => todo!(),
+            State::BusyClass1Nacked => todo!(),
+            State::BusyClass2Acked => todo!(),
+        }
+    }
 }
diff --git a/satrs-core/src/cfdp/mod.rs b/satrs-core/src/cfdp/mod.rs
index f62bd14..811c820 100644
--- a/satrs-core/src/cfdp/mod.rs
+++ b/satrs-core/src/cfdp/mod.rs
@@ -7,7 +7,7 @@ pub enum TransactionStep {
     ReceivingFileDataPdus = 2,
     SendingAckPdu = 3,
     TransferCompletion = 4,
-    SendingFinishedPdu = 5
+    SendingFinishedPdu = 5,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -20,6 +20,5 @@ pub enum State {
 #[cfg(test)]
 mod tests {
     #[test]
-    fn basic_test() {
-    }
+    fn basic_test() {}
 }
diff --git a/satrs-core/src/lib.rs b/satrs-core/src/lib.rs
index 6484cc8..949ffa5 100644
--- a/satrs-core/src/lib.rs
+++ b/satrs-core/src/lib.rs
@@ -20,6 +20,7 @@ extern crate downcast_rs;
 #[cfg(any(feature = "std", test))]
 extern crate std;
 
+pub mod cfdp;
 pub mod error;
 #[cfg(feature = "alloc")]
 #[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
@@ -40,7 +41,6 @@ pub mod request;
 pub mod res_code;
 pub mod seq_count;
 pub mod tmtc;
-pub mod cfdp;
 
 pub use spacepackets;