Merge pull request #3790 from Roasbeef/pay-size-consistency

multi: make SendToRoute consistent with other payment RPC

fundingmanager.go

@@ -2359,6 +2359,9 @@ func (f *fundingManager) annAfterSixConfs(completeChan *channeldb.OpenChannel,
 		if fwdMaxHTLC > capacityMSat {
 			fwdMaxHTLC = capacityMSat
 		}
+		if fwdMaxHTLC > MaxPaymentMSat {
+			fwdMaxHTLC = MaxPaymentMSat
+		}
 
 		// Create and broadcast the proofs required to make this channel
 		// public and usable for other nodes for routing.

htlcswitch/link.go

@@ -257,9 +257,9 @@ type ChannelLinkConfig struct {
 	// configured set of watchtowers.
 	TowerClient TowerClient
 
-	// MaxCltvExpiry is the maximum outgoing timelock that the link should
-	// accept for a forwarded HTLC. The value is relative to the current
-	// block height.
+	// MaxOutgoingCltvExpiry is the maximum outgoing timelock that the link
+	// should accept for a forwarded HTLC. The value is relative to the
+	// current block height.
 	MaxOutgoingCltvExpiry uint32
 
 	// MaxFeeAllocation is the highest allocation we'll allow a channel's

lnrpc/routerrpc/router_backend.go

@@ -470,6 +470,13 @@ func (r *RouterBackend) UnmarshallRoute(rpcroute *lnrpc.Route) (
 			return nil, err
 		}
 
+		if routeHop.AmtToForward > r.MaxPaymentMSat {
+			return nil, fmt.Errorf("payment of %v is too large, "+
+				"max payment allowed is %v",
+				routeHop.AmtToForward,
+				r.MaxPaymentMSat.ToSatoshis())
+		}
+
 		hops[i] = routeHop
 
 		prevNodePubKey = routeHop.PubKeyBytes

peer.go

@@ -535,6 +535,9 @@ func (p *peer) loadActiveChannels(chans []*channeldb.OpenChannel) (
 				FeeRate:       selfPolicy.FeeProportionalMillionths,
 				TimeLockDelta: uint32(selfPolicy.TimeLockDelta),
 			}
+			if forwardingPolicy.MaxHTLC > MaxPaymentMSat {
+				forwardingPolicy.MaxHTLC = MaxPaymentMSat
+			}
 		} else {
 			peerLog.Warnf("Unable to find our forwarding policy "+
 				"for channel %v, using default values",
@@ -1866,6 +1869,9 @@ out:
 				FeeRate:       defaultPolicy.FeeRate,
 				TimeLockDelta: defaultPolicy.TimeLockDelta,
 			}
+			if forwardingPolicy.MaxHTLC > MaxPaymentMSat {
+				forwardingPolicy.MaxHTLC = MaxPaymentMSat
+			}
 
 			// Create the link and add it to the switch.
 			err = p.addLink(