routing: convert to node pair based

Previously mission control tracked failures on a per node, per channel basis.
This commit changes this to tracking on the level of directed node pairs. The goal
of moving to this coarser-grained level is to reduce the number of required
payment attempts without compromising payment reliability.

cmd/lncli/cmd_query_mission_control.go

@@ -32,24 +32,43 @@ func queryMissionControl(ctx *cli.Context) error {
 	}
 
 	type displayNodeHistory struct {
-		Pubkey               string
-		LastFailTime         int64
-		OtherChanSuccessProb float32
-		Channels             []*routerrpc.ChannelHistory
+		Pubkey           string
+		LastFailTime     int64
+		OtherSuccessProb float32
+	}
+
+	type displayPairHistory struct {
+		NodeFrom, NodeTo  string
+		LastFailTime      int64
+		SuccessProb       float32
+		MinPenalizeAmtSat int64
 	}
 
 	displayResp := struct {
 		Nodes []displayNodeHistory
+		Pairs []displayPairHistory
 	}{}
 
 	for _, n := range snapshot.Nodes {
 		displayResp.Nodes = append(
 			displayResp.Nodes,
 			displayNodeHistory{
-				Pubkey:               hex.EncodeToString(n.Pubkey),
-				LastFailTime:         n.LastFailTime,
-				OtherChanSuccessProb: n.OtherChanSuccessProb,
-				Channels:             n.Channels,
+				Pubkey:           hex.EncodeToString(n.Pubkey),
+				LastFailTime:     n.LastFailTime,
+				OtherSuccessProb: n.OtherSuccessProb,
+			},
+		)
+	}
+
+	for _, n := range snapshot.Pairs {
+		displayResp.Pairs = append(
+			displayResp.Pairs,
+			displayPairHistory{
+				NodeFrom:          hex.EncodeToString(n.NodeFrom),
+				NodeTo:            hex.EncodeToString(n.NodeTo),
+				LastFailTime:      n.LastFailTime,
+				SuccessProb:       n.SuccessProb,
+				MinPenalizeAmtSat: n.MinPenalizeAmtSat,
 			},
 		)
 	}