2020-11-12 00:06:34 +00:00
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use crate::{
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2020-12-10 02:19:18 +00:00
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bob::{event_loop::EventLoopHandle, execution::negotiate},
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2020-11-12 00:06:34 +00:00
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storage::Database,
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2020-11-30 02:25:11 +00:00
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SwapAmounts,
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2020-11-12 00:06:34 +00:00
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};
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use anyhow::Result;
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use async_recursion::async_recursion;
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2020-12-01 03:30:02 +00:00
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use libp2p::{core::Multiaddr, PeerId};
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2020-11-30 02:25:11 +00:00
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use rand::{CryptoRng, RngCore};
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2020-12-02 01:36:47 +00:00
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use std::{fmt, sync::Arc};
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2020-12-07 02:31:14 +00:00
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use tracing::info;
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2020-11-12 00:06:34 +00:00
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use uuid::Uuid;
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2020-11-30 02:25:11 +00:00
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use xmr_btc::bob::{self};
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2020-11-12 00:06:34 +00:00
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// The same data structure is used for swap execution and recovery.
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// This allows for a seamless transition from a failed swap to recovery.
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pub enum BobState {
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2020-11-30 02:25:11 +00:00
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Started {
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state0: bob::State0,
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amounts: SwapAmounts,
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peer_id: PeerId,
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2020-12-01 03:30:02 +00:00
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addr: Multiaddr,
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2020-11-30 02:25:11 +00:00
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},
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2020-11-12 00:06:34 +00:00
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Negotiated(bob::State2, PeerId),
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BtcLocked(bob::State3, PeerId),
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XmrLocked(bob::State4, PeerId),
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EncSigSent(bob::State4, PeerId),
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BtcRedeemed(bob::State5),
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Cancelled(bob::State4),
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BtcRefunded,
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XmrRedeemed,
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Punished,
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SafelyAborted,
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}
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2020-12-02 01:36:47 +00:00
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impl fmt::Display for BobState {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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match self {
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BobState::Started { .. } => write!(f, "started"),
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BobState::Negotiated(..) => write!(f, "negotiated"),
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BobState::BtcLocked(..) => write!(f, "btc_locked"),
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BobState::XmrLocked(..) => write!(f, "xmr_locked"),
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BobState::EncSigSent(..) => write!(f, "encsig_sent"),
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BobState::BtcRedeemed(_) => write!(f, "btc_redeemed"),
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BobState::Cancelled(_) => write!(f, "cancelled"),
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BobState::BtcRefunded => write!(f, "btc_refunded"),
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BobState::XmrRedeemed => write!(f, "xmr_redeemed"),
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BobState::Punished => write!(f, "punished"),
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BobState::SafelyAborted => write!(f, "safely_aborted"),
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}
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}
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}
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2020-12-02 01:09:43 +00:00
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pub async fn swap<R>(
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state: BobState,
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2020-12-10 02:55:29 +00:00
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event_loop_handle: EventLoopHandle,
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2020-12-02 01:09:43 +00:00
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db: Database,
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bitcoin_wallet: Arc<crate::bitcoin::Wallet>,
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monero_wallet: Arc<crate::monero::Wallet>,
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rng: R,
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swap_id: Uuid,
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) -> Result<BobState>
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2020-12-02 01:36:47 +00:00
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where
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R: RngCore + CryptoRng + Send,
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2020-12-02 01:09:43 +00:00
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{
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2020-12-02 01:36:47 +00:00
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run_until(
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state,
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is_complete,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:36:47 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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.await
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2020-12-02 01:09:43 +00:00
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}
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pub fn is_complete(state: &BobState) -> bool {
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2020-12-02 01:36:47 +00:00
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matches!(
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state,
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BobState::BtcRefunded
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| BobState::XmrRedeemed
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| BobState::Punished
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| BobState::SafelyAborted
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)
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}
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pub fn is_btc_locked(state: &BobState) -> bool {
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matches!(state, BobState::BtcLocked(..))
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}
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pub fn is_xmr_locked(state: &BobState) -> bool {
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matches!(state, BobState::XmrLocked(..))
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2020-12-02 01:09:43 +00:00
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}
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2020-11-12 00:06:34 +00:00
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// State machine driver for swap execution
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2020-12-02 01:36:47 +00:00
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#[allow(clippy::too_many_arguments)]
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2020-11-12 00:06:34 +00:00
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#[async_recursion]
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2020-12-02 01:09:43 +00:00
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pub async fn run_until<R>(
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2020-11-12 00:06:34 +00:00
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state: BobState,
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2020-12-02 01:36:47 +00:00
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is_target_state: fn(&BobState) -> bool,
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2020-12-10 02:55:29 +00:00
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mut event_loop_handle: EventLoopHandle,
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2020-11-12 00:06:34 +00:00
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db: Database,
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bitcoin_wallet: Arc<crate::bitcoin::Wallet>,
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monero_wallet: Arc<crate::monero::Wallet>,
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2020-11-30 02:25:11 +00:00
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mut rng: R,
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2020-11-26 02:55:56 +00:00
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swap_id: Uuid,
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2020-11-30 02:25:11 +00:00
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) -> Result<BobState>
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where
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R: RngCore + CryptoRng + Send,
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{
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2020-12-07 02:55:13 +00:00
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info!("Current state: {}", state);
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2020-12-02 01:36:47 +00:00
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if is_target_state(&state) {
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2020-12-02 01:09:43 +00:00
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Ok(state)
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} else {
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match state {
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BobState::Started {
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2020-11-30 02:25:11 +00:00
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state0,
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amounts,
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2020-12-02 01:09:43 +00:00
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peer_id,
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2020-12-01 03:30:02 +00:00
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addr,
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2020-12-02 01:09:43 +00:00
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} => {
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let state2 = negotiate(
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state0,
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amounts,
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2020-12-10 02:55:29 +00:00
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&mut event_loop_handle,
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2020-12-02 01:09:43 +00:00
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addr,
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&mut rng,
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bitcoin_wallet.clone(),
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)
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2020-12-02 01:36:47 +00:00
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.await?;
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2020-12-02 01:09:43 +00:00
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run_until(
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BobState::Negotiated(state2, peer_id),
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2020-12-02 01:36:47 +00:00
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:09:43 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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2020-12-02 01:36:47 +00:00
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.await
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2020-12-02 01:09:43 +00:00
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}
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BobState::Negotiated(state2, alice_peer_id) => {
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// Alice and Bob have exchanged info
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let state3 = state2.lock_btc(bitcoin_wallet.as_ref()).await?;
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// db.insert_latest_state(state);
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run_until(
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BobState::BtcLocked(state3, alice_peer_id),
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2020-12-02 01:36:47 +00:00
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:09:43 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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2020-12-02 01:36:47 +00:00
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.await
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2020-12-02 01:09:43 +00:00
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}
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// Bob has locked Btc
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// Watch for Alice to Lock Xmr or for t1 to elapse
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BobState::BtcLocked(state3, alice_peer_id) => {
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// todo: watch until t1, not indefinetely
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2020-12-10 02:55:29 +00:00
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let msg2 = event_loop_handle.recv_message2().await?;
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2020-12-07 02:31:14 +00:00
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let state4 = state3
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.watch_for_lock_xmr(monero_wallet.as_ref(), msg2)
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.await?;
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2020-12-02 01:09:43 +00:00
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run_until(
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BobState::XmrLocked(state4, alice_peer_id),
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2020-12-02 01:36:47 +00:00
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:09:43 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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2020-12-02 01:36:47 +00:00
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.await
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2020-12-02 01:09:43 +00:00
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}
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BobState::XmrLocked(state, alice_peer_id) => {
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// Alice has locked Xmr
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// Bob sends Alice his key
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let tx_redeem_encsig = state.tx_redeem_encsig();
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// Do we have to wait for a response?
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// What if Alice fails to receive this? Should we always resend?
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// todo: If we cannot dial Alice we should go to EncSigSent. Maybe dialing
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// should happen in this arm?
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2020-12-10 02:55:29 +00:00
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event_loop_handle
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2020-12-09 03:10:24 +00:00
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.send_message3(alice_peer_id.clone(), tx_redeem_encsig)
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.await?;
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2020-11-12 00:06:34 +00:00
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2020-12-02 01:09:43 +00:00
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run_until(
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BobState::EncSigSent(state, alice_peer_id),
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2020-12-02 01:36:47 +00:00
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:09:43 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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2020-12-02 01:36:47 +00:00
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.await
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2020-12-02 01:09:43 +00:00
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}
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BobState::EncSigSent(state, ..) => {
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// Watch for redeem
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let redeem_watcher = state.watch_for_redeem_btc(bitcoin_wallet.as_ref());
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let t1_timeout = state.wait_for_t1(bitcoin_wallet.as_ref());
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2020-11-12 00:06:34 +00:00
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2020-12-02 01:09:43 +00:00
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tokio::select! {
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2020-12-02 01:36:47 +00:00
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val = redeem_watcher => {
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run_until(
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BobState::BtcRedeemed(val?),
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:36:47 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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.await
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2020-11-12 00:06:34 +00:00
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}
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2020-12-02 01:36:47 +00:00
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_ = t1_timeout => {
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// Check whether TxCancel has been published.
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// We should not fail if the transaction is already on the blockchain
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if state.check_for_tx_cancel(bitcoin_wallet.as_ref()).await.is_err() {
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state.submit_tx_cancel(bitcoin_wallet.as_ref()).await?;
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}
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2020-11-12 00:06:34 +00:00
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2020-12-02 01:36:47 +00:00
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run_until(
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BobState::Cancelled(state),
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:36:47 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id
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)
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.await
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2020-11-12 00:06:34 +00:00
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2020-12-02 01:36:47 +00:00
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}
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2020-11-12 00:06:34 +00:00
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}
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}
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2020-12-02 01:09:43 +00:00
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BobState::BtcRedeemed(state) => {
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// Bob redeems XMR using revealed s_a
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state.claim_xmr(monero_wallet.as_ref()).await?;
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run_until(
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BobState::XmrRedeemed,
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2020-12-02 01:36:47 +00:00
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is_target_state,
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2020-12-10 02:55:29 +00:00
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event_loop_handle,
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2020-12-02 01:09:43 +00:00
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db,
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bitcoin_wallet,
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monero_wallet,
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rng,
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swap_id,
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)
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2020-12-02 01:36:47 +00:00
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.await
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}
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BobState::Cancelled(_state) => {
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// Bob has cancelled the swap
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// If <t2 Bob refunds
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// if unimplemented!("<t2") {
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// // Submit TxRefund
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// abort(BobState::BtcRefunded, io).await
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// } else {
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// // Bob failed to refund in time and has been punished
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// abort(BobState::Punished, io).await
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// }
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Ok(BobState::BtcRefunded)
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}
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2020-12-10 00:51:58 +00:00
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BobState::BtcRefunded => Ok(BobState::BtcRefunded),
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BobState::Punished => Ok(BobState::Punished),
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BobState::SafelyAborted => Ok(BobState::SafelyAborted),
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BobState::XmrRedeemed => Ok(BobState::XmrRedeemed),
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2020-11-12 00:06:34 +00:00
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}
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}
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}
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