Add acknowledge message at the end of rollover

This is to avoid going on chain in a scenario where one party finished the rollover, while the other party ran into a timeout after send-/receiving the last message for the revoke-commit.

daemon/src/setup_contract.rs

@@ -2,7 +2,8 @@ use crate::model::cfd::{Cet, Dlc, RevokedCommit, Role};
 use crate::model::{Leverage, Price, Usd};
 use crate::tokio_ext::FutureExt;
 use crate::wire::{
-    Msg0, Msg1, Msg2, Msg3, RollOverMsg, RollOverMsg0, RollOverMsg1, RollOverMsg2, SetupMsg,
+    Msg0, Msg1, Msg2, Msg3, RollOverMsg, RollOverMsg0, RollOverMsg1, RollOverMsg2, RollOverMsg3,
+    SetupMsg,
 };
 use crate::{model, oracle, payout_curve, wallet};
 use anyhow::{Context, Result};
@@ -573,6 +574,19 @@ pub async fn roll_over(
         script_pubkey: dlc.commit.2.script_pubkey(),
     });
 
+    // TODO: Remove send- and receiving ACK messages once we are able to handle incomplete DLC
+    // monitoring
+    sink.send(RollOverMsg::Msg3(RollOverMsg3))
+        .await
+        .context("Failed to send Msg3")?;
+    let _ = stream
+        .select_next_some()
+        .timeout(Duration::from_secs(60))
+        .await
+        .context("Expected Msg3 within 60 seconds")?
+        .try_into_msg3()
+        .context("Failed to read Msg3")?;
+
     Ok(Dlc {
         identity: sk,
         identity_counterparty: dlc.identity_counterparty,

daemon/src/wire.rs

@@ -358,6 +358,7 @@ pub enum RollOverMsg {
     Msg0(RollOverMsg0),
     Msg1(RollOverMsg1),
     Msg2(RollOverMsg2),
+    Msg3(RollOverMsg3),
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -390,6 +391,14 @@ impl RollOverMsg {
             bail!("Not Msg2")
         }
     }
+
+    pub fn try_into_msg3(self) -> Result<RollOverMsg3> {
+        if let Self::Msg3(v) = self {
+            Ok(v)
+        } else {
+            bail!("Not Msg3")
+        }
+    }
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -404,6 +413,9 @@ pub struct RollOverMsg2 {
     pub revocation_sk: SecretKey,
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct RollOverMsg3;
+
 impl From<CfdTransactions> for RollOverMsg1 {
     fn from(txs: CfdTransactions) -> Self {
         let cets = txs