feat(swaps): timeout stalled swaps

This adds timeouts to all swap deals to fail them after a certain
amount of time. Current time limits are set to 10 seconds for a swap to
be accepted and 30 seconds for a swap to be completed once accepted.
Previously, swaps that stalled out due to an unresponsive peer or swap
client would last indefinitely and the corresponding order would remain
on hold.

Closes #653.

lib/swaps/Swaps.ts

@@ -29,10 +29,16 @@ interface Swaps {
 class Swaps extends EventEmitter {
   /** A map between payment hashes and swap deals. */
   private deals = new Map<string, SwapDeal>();
+  /** A map between payment hashes and timeouts for swaps. */
+  private timeouts = new Map<string, number>();
   private usedHashes = new Set<string>();
   private repository: SwapRepository;
   /** The number of satoshis in a bitcoin. */
   private static readonly SATOSHIS_PER_COIN = 100000000;
+  /** The maximum time in milliseconds we will wait for a swap to be accepted before failing it. */
+  private static readonly SWAP_ACCEPT_TIMEOUT = 10000;
+  /** The maximum time in milliseconds we will wait for a swap to be completed before failing it. */
+  private static readonly SWAP_COMPLETE_TIMEOUT = 30000;
 
   constructor(private logger: Logger, private models: Models, private pool: Pool, private lndBtcClient: LndClient, private lndLtcClient: LndClient) {
     super();
@@ -293,9 +299,11 @@ class Swaps extends EventEmitter {
     }
     const preimage = await randomBytes(32);
 
+    const rHash = createHash('sha256').update(preimage).digest('hex');
+
     const swapRequestBody: packets.SwapRequestPacketBody = {
       takerCltvDelta,
-      rHash: createHash('sha256').update(preimage).digest('hex'),
+      rHash,
       orderId: maker.id,
       pairId: maker.pairId,
       proposedQuantity: taker.quantity,
@@ -318,6 +326,8 @@ class Swaps extends EventEmitter {
       createTime: Date.now(),
     };
 
+    this.timeouts.set(rHash, setTimeout(this.handleSwapTimeout, Swaps.SWAP_ACCEPT_TIMEOUT, rHash));
+
     this.addDeal(deal);
 
     // Verify LND setup. Make sure we are connected to BTC and LTC and that
@@ -344,7 +354,8 @@ class Swaps extends EventEmitter {
     // TODO: consider the time gap between taking the routes and using them.
     // TODO: multi route support (currently only 1)
 
-    if (this.usedHashes.has(requestPacket.body!.rHash)) {
+    const rHash = requestPacket.body!.rHash;
+    if (this.usedHashes.has(rHash)) {
       this.sendErrorToPeer(peer, requestPacket.body!.rHash, SwapFailureReason.PaymentHashReuse, undefined, requestPacket.header.id);
       return false;
     }
@@ -376,6 +387,8 @@ class Swaps extends EventEmitter {
       createTime: Date.now(),
     };
 
+    this.timeouts.set(rHash, setTimeout(this.handleSwapTimeout, Swaps.SWAP_COMPLETE_TIMEOUT, rHash));
+
     // add the deal. Going forward we can "record" errors related to this deal.
     this.addDeal(deal);
 
@@ -454,10 +467,19 @@ class Swaps extends EventEmitter {
     const { quantity, rHash, makerCltvDelta } = responsePacket.body!;
     const deal = this.getDeal(rHash);
     if (!deal) {
-      this.logger.error(`received swap accepted for unrecognized deal payment hash ${rHash}`);
+      this.logger.warn(`received swap accepted for unrecognized deal: ${rHash}`);
+      // TODO: penalize peer
+      return;
+    }
+    if (deal.phase !== SwapPhase.SwapRequested) {
+      this.logger.warn(`received swap accepted for deal that is not in SwapRequested phase: ${rHash}`);
+      // TODO: penalize peer
       return;
     }
 
+    clearTimeout(this.timeouts.get(rHash));
+    this.timeouts.set(rHash, setTimeout(this.handleSwapTimeout, Swaps.SWAP_COMPLETE_TIMEOUT, rHash));
+
     // update deal with taker's makerCltvDelta
     deal.makerCltvDelta = makerCltvDelta;
 
@@ -636,6 +658,12 @@ class Swaps extends EventEmitter {
 
   }
 
+  private handleSwapTimeout = (rHash: string) => {
+    const deal = this.getDeal(rHash)!;
+    this.timeouts.delete(rHash);
+    this.failDeal(deal, SwapFailureReason.Timeout);
+  }
+
   private failDeal = (deal: SwapDeal, failureReason: SwapFailureReason, errorMessage?: string): void => {
     // If we are already in error state and got another error report we
     // aggregate all error reasons by concatenation
@@ -650,6 +678,8 @@ class Swaps extends EventEmitter {
     deal.state = SwapState.Error;
     deal.failureReason = failureReason;
     deal.errorMessage = errorMessage;
+    clearTimeout(this.timeouts.get(deal.rHash));
+    this.timeouts.delete(deal.rHash);
     this.emit('swap.failed', deal);
   }
 
@@ -708,6 +738,9 @@ class Swaps extends EventEmitter {
         role: deal.role,
       };
       this.emit('swap.paid', swapResult);
+
+      clearTimeout(this.timeouts.get(deal.rHash));
+      this.timeouts.delete(deal.rHash);
     }
   }
 

lib/swaps/types.ts

@@ -52,7 +52,7 @@ export type SwapDeal = {
   makerToTakerRoutes?: Route[];
   createTime: number;
   executeTime?: number;
-  completeTime?: number
+  completeTime?: number;
 };
 
 /** The result of a successful swap. */

lib/types/enums.ts

@@ -84,6 +84,7 @@ export enum SwapFailureReason {
   InvalidResolveRequest = 8,
   /** The swap request attempts to reuse a payment hash. */
   PaymentHashReuse = 9,
+  Timeout = 10,
 }
 
 export enum DisconnectionReason {