rpcserver+fundingmanager: thread remote_max_htlcs to channel opening

rpcserver.go

@@ -1742,6 +1742,7 @@ func (r *rpcServer) parseOpenChannelReq(in *lnrpc.OpenChannelRequest,
 	minHtlcIn := lnwire.MilliSatoshi(in.MinHtlcMsat)
 	remoteCsvDelay := uint16(in.RemoteCsvDelay)
 	maxValue := lnwire.MilliSatoshi(in.RemoteMaxValueInFlightMsat)
+	maxHtlcs := uint16(in.RemoteMaxHtlcs)
 
 	globalFeatureSet := r.server.featureMgr.Get(feature.SetNodeAnn)
 
@@ -1774,6 +1775,13 @@ func (r *rpcServer) parseOpenChannelReq(in *lnrpc.OpenChannelRequest,
 			"channel size is: %v SAT", int64(minChanFundingSize))
 	}
 
+	// Prevent users from submitting a max-htlc value that would exceed the
+	// protocol maximum.
+	if maxHtlcs > input.MaxHTLCNumber/2 {
+		return nil, fmt.Errorf("remote-max-htlcs (%v) cannot be "+
+			"greater than %v", maxHtlcs, input.MaxHTLCNumber/2)
+	}
+
 	// Then, we'll extract the minimum number of confirmations that each
 	// output we use to fund the channel's funding transaction should
 	// satisfy.
@@ -1862,6 +1870,7 @@ func (r *rpcServer) parseOpenChannelReq(in *lnrpc.OpenChannelRequest,
 		minConfs:         minConfs,
 		shutdownScript:   script,
 		maxValueInFlight: maxValue,
+		maxHtlcs:         maxHtlcs,
 	}, nil
 }