liquidity: exclude peers for easy autoloop

Author: hieblmi

liquidity/liquidity.go

@@ -1666,9 +1666,24 @@ func (m *Manager) pickEasyAutoloopChannel(channels []lndclient.ChannelInfo,
 		return channels[i].LocalBalance > channels[j].LocalBalance
 	})
 
-	// Check each channel, since channels are already sorted we return the
+	// Build a set of excluded peers for a quick lookup.
+	excluded := make(map[route.Vertex]struct{})
+	for _, v := range m.params.EasyAutoloopExcludedPeers {
+		excluded[v] = struct{}{}
+	}
+
+	// Check each channel, since channels are already sorted, we return the
 	// first channel that passes all checks.
 	for _, channel := range channels {
+		// Skip channels whose remote peer is excluded for easy autoloop.
+		if _, ok := excluded[channel.PubKeyBytes]; ok {
+			log.Debugf("Channel %v cannot be used for easy "+
+				"autoloop: peer %x excluded", channel.ChannelID,
+				channel.PubKeyBytes)
+
+			continue
+		}
+
 		shortChanID := lnwire.NewShortChanIDFromInt(channel.ChannelID)
 
 		if !channel.Active {

liquidity/parameters.go

@@ -116,6 +116,10 @@ type Parameters struct {
 	// maintain in our channels.
 	EasyAutoloopTarget btcutil.Amount
 
+	// EasyAutoloopExcludedPeers is an optional list of peers that should be
+	// excluded from being selected for easy autoloop swaps.
+	EasyAutoloopExcludedPeers []route.Vertex
+
 	// AssetAutoloopParams maps an asset id hex encoded string to its
 	// easy autoloop parameters.
 	AssetAutoloopParams map[string]AssetParams
@@ -481,6 +485,17 @@ func RpcToParameters(req *clientrpc.LiquidityParameters) (*Parameters,
 				time.Second
 	}
 
+	// Map excluded peers for easy autoloop, if any.
+	for _, p := range req.GetEasyAutoloopExcludedPeers() {
+		v, err := route.NewVertexFromBytes(p)
+		if err != nil {
+			return nil, err
+		}
+		params.EasyAutoloopExcludedPeers = append(
+			params.EasyAutoloopExcludedPeers, v,
+		)
+	}
+
 	// If an old-style budget was written to storage then express it by
 	// using the new auto budget parameters. If the newly added parameters
 	// have the 0 default value, but a budget was defined that means the
@@ -603,6 +618,13 @@ func ParametersToRpc(cfg Parameters) (*clientrpc.LiquidityParameters,
 		EasyAssetParams:            easyAssetMap,
 		FastSwapPublication:        cfg.FastSwapPublication,
 	}
+	// Set excluded peers for easy autoloop.
+	for _, v := range cfg.EasyAutoloopExcludedPeers {
+		b := v[:]
+		rpcCfg.EasyAutoloopExcludedPeers = append(
+			rpcCfg.EasyAutoloopExcludedPeers, b,
+		)
+	}
 
 	switch f := cfg.FeeLimit.(type) {
 	case *FeeCategoryLimit: