Allow Bob to exit execution at a specified state

This commit is contained in:
rishflab 2020-12-02 12:09:43 +11:00
parent 150e5f2aba
commit 584cc22024
2 changed files with 157 additions and 120 deletions

1
Cargo.lock generated
View File

@ -3369,6 +3369,7 @@ dependencies = [
"bitcoin",
"bitcoin-harness",
"conquer-once",
"conquer-once",
"derivative",
"ecdsa_fun",
"futures",

View File

@ -33,10 +33,31 @@ pub enum BobState {
SafelyAborted,
}
// State machine driver for swap execution
#[async_recursion]
pub async fn swap<R>(
state: BobState,
swarm: Swarm,
db: Database,
bitcoin_wallet: Arc<crate::bitcoin::Wallet>,
monero_wallet: Arc<crate::monero::Wallet>,
rng: R,
swap_id: Uuid,
) -> Result<BobState>
where
R: RngCore + CryptoRng + Send,
{
run_until(state, is_complete, swarm, db, bitcoin_wallet, monero_wallet, rng, swap_id).await
}
// TODO: use macro or generics
pub fn is_complete(state: &BobState) -> bool {
matches!(state, BobState::BtcRefunded| BobState::XmrRedeemed | BobState::Punished | BobState::SafelyAborted)
}
// State machine driver for swap execution
#[async_recursion]
pub async fn run_until<R>(
state: BobState,
is_state: fn(&BobState) -> bool,
mut swarm: Swarm,
db: Database,
bitcoin_wallet: Arc<crate::bitcoin::Wallet>,
@ -47,112 +68,120 @@ pub async fn swap<R>(
where
R: RngCore + CryptoRng + Send,
{
match state {
BobState::Started {
state0,
amounts,
peer_id,
addr,
} => {
let state2 = negotiate(
if is_state(&state) {
Ok(state)
} else {
match state {
BobState::Started {
state0,
amounts,
&mut swarm,
peer_id,
addr,
&mut rng,
bitcoin_wallet.clone(),
)
.await?;
swap(
BobState::Negotiated(state2, peer_id),
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::Negotiated(state2, alice_peer_id) => {
// Alice and Bob have exchanged info
let state3 = state2.lock_btc(bitcoin_wallet.as_ref()).await?;
// db.insert_latest_state(state);
swap(
BobState::BtcLocked(state3, alice_peer_id),
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
// Bob has locked Btc
// Watch for Alice to Lock Xmr or for t1 to elapse
BobState::BtcLocked(state3, alice_peer_id) => {
// todo: watch until t1, not indefinetely
let state4 = match swarm.next().await {
OutEvent::Message2(msg) => {
state3
.watch_for_lock_xmr(monero_wallet.as_ref(), msg)
.await?
}
other => panic!("unexpected event: {:?}", other),
};
swap(
BobState::XmrLocked(state4, alice_peer_id),
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::XmrLocked(state, alice_peer_id) => {
// Alice has locked Xmr
// Bob sends Alice his key
let tx_redeem_encsig = state.tx_redeem_encsig();
// Do we have to wait for a response?
// What if Alice fails to receive this? Should we always resend?
// todo: If we cannot dial Alice we should go to EncSigSent. Maybe dialing
// should happen in this arm?
swarm.send_message3(alice_peer_id.clone(), tx_redeem_encsig);
} => {
let state2 = negotiate(
state0,
amounts,
&mut swarm,
addr,
&mut rng,
bitcoin_wallet.clone(),
)
.await?;
run_until(
BobState::Negotiated(state2, peer_id),
is_state,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::Negotiated(state2, alice_peer_id) => {
// Alice and Bob have exchanged info
let state3 = state2.lock_btc(bitcoin_wallet.as_ref()).await?;
// db.insert_latest_state(state);
run_until(
BobState::BtcLocked(state3, alice_peer_id),
is_state,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
// Bob has locked Btc
// Watch for Alice to Lock Xmr or for t1 to elapse
BobState::BtcLocked(state3, alice_peer_id) => {
// todo: watch until t1, not indefinetely
let state4 = match swarm.next().await {
OutEvent::Message2(msg) => {
state3
.watch_for_lock_xmr(monero_wallet.as_ref(), msg)
.await?
}
other => panic!("unexpected event: {:?}", other),
};
run_until(
BobState::XmrLocked(state4, alice_peer_id),
is_state,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::XmrLocked(state, alice_peer_id) => {
// Alice has locked Xmr
// Bob sends Alice his key
let tx_redeem_encsig = state.tx_redeem_encsig();
// Do we have to wait for a response?
// What if Alice fails to receive this? Should we always resend?
// todo: If we cannot dial Alice we should go to EncSigSent. Maybe dialing
// should happen in this arm?
swarm.send_message3(alice_peer_id.clone(), tx_redeem_encsig);
// Sadly we have to poll the swarm to get make sure the message is sent?
// FIXME: Having to wait for Alice's response here is a big problem, because
// we're stuck if she doesn't send her response back. I believe this is
// currently necessary, so we may have to rework this and/or how we use libp2p
match swarm.next().await {
OutEvent::Message3 => {
debug!("Got Message3 empty response");
}
other => panic!("unexpected event: {:?}", other),
};
// Sadly we have to poll the swarm to get make sure the message is sent?
// FIXME: Having to wait for Alice's response here is a big problem, because
// we're stuck if she doesn't send her response back. I believe this is
// currently necessary, so we may have to rework this and/or how we use libp2p
match swarm.next().await {
OutEvent::Message3 => {
debug!("Got Message3 empty response");
}
other => panic!("unexpected event: {:?}", other),
};
swap(
BobState::EncSigSent(state, alice_peer_id),
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::EncSigSent(state, ..) => {
// Watch for redeem
let redeem_watcher = state.watch_for_redeem_btc(bitcoin_wallet.as_ref());
let t1_timeout = state.wait_for_t1(bitcoin_wallet.as_ref());
run_until(
BobState::EncSigSent(state, alice_peer_id),
is_state,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::EncSigSent(state, ..) => {
// Watch for redeem
let redeem_watcher = state.watch_for_redeem_btc(bitcoin_wallet.as_ref());
let t1_timeout = state.wait_for_t1(bitcoin_wallet.as_ref());
tokio::select! {
tokio::select! {
val = redeem_watcher => {
swap(
run_until(
BobState::BtcRedeemed(val?),
is_state,
swarm,
db,
bitcoin_wallet,
@ -169,8 +198,9 @@ where
state.submit_tx_cancel(bitcoin_wallet.as_ref()).await?;
}
swap(
run_until(
BobState::Cancelled(state),
is_state,
swarm,
db,
bitcoin_wallet,
@ -182,29 +212,35 @@ where
}
}
}
BobState::BtcRedeemed(state) => {
// Bob redeems XMR using revealed s_a
state.claim_xmr(monero_wallet.as_ref()).await?;
run_until(
BobState::XmrRedeemed,
is_state,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::Cancelled(_state) => Ok(BobState::BtcRefunded),
BobState::BtcRefunded => Ok(BobState::BtcRefunded),
BobState::Punished => Ok(BobState::Punished),
BobState::SafelyAborted => Ok(BobState::SafelyAborted),
BobState::XmrRedeemed => Ok(BobState::XmrRedeemed),
}
BobState::BtcRedeemed(state) => {
// Bob redeems XMR using revealed s_a
state.claim_xmr(monero_wallet.as_ref()).await?;
swap(
BobState::XmrRedeemed,
swarm,
db,
bitcoin_wallet,
monero_wallet,
rng,
swap_id,
)
.await
}
BobState::Cancelled(_state) => Ok(BobState::BtcRefunded),
BobState::BtcRefunded => Ok(BobState::BtcRefunded),
BobState::Punished => Ok(BobState::Punished),
BobState::SafelyAborted => Ok(BobState::SafelyAborted),
BobState::XmrRedeemed => Ok(BobState::XmrRedeemed),
}
}
// // State machine driver for recovery execution
// #[async_recursion]
// pub async fn abort(state: BobState, io: Io) -> Result<BobState> {