Fix bug in routing table health calculation.

kademlia/health.go

@@ -81,6 +81,14 @@ func AllTablesHealth(tables []*Table) (report []*TableHealthReport) {
 	return
 }
 
+func TableHealthFromSets(node key.Key, nodeContacts []key.Key, knownNodes []key.Key) *TableHealthReport {
+	knownNodesTrie := trie.New()
+	for _, k := range knownNodes {
+		knownNodesTrie.Add(k)
+	}
+	return TableHealth(node, nodeContacts, knownNodesTrie)
+}
+
 // TableHealth computes the health report for a node,
 // given its routing contacts and a list of all known nodes in the network currently.
 func TableHealth(node key.Key, nodeContacts []key.Key, knownNodes *trie.Trie) *TableHealthReport {
@@ -114,6 +122,7 @@ func walkBucketHealth(depth int, node key.Key, nodeTable, knownNodes *trie.Trie)
 	} else {
 		dir := node.BitAt(depth)
 		switch {
+		//
 		case knownNodes == nil || knownNodes.IsEmptyLeaf():
 			r := walkBucketHealth(depth+1, node, nodeTable.Branch[dir], nil)
 			return append(r,
@@ -135,12 +144,12 @@ func walkBucketHealth(depth int, node key.Key, nodeTable, knownNodes *trie.Trie)
 					})
 			} else {
 				r := walkBucketHealth(depth+1, node, nodeTable.Branch[dir], nil)
-				return append(r, bucketReportFromTries(depth, nodeTable.Branch[1-dir], knownNodes))
+				return append(r, bucketReportFromTries(depth+1, nodeTable.Branch[1-dir], knownNodes))
 			}
 		case !knownNodes.IsLeaf():
 			r := walkBucketHealth(depth+1, node, nodeTable.Branch[dir], knownNodes.Branch[dir])
 			return append(r,
-				bucketReportFromTries(depth, nodeTable.Branch[1-dir], knownNodes.Branch[1-dir]))
+				bucketReportFromTries(depth+1, nodeTable.Branch[1-dir], knownNodes.Branch[1-dir]))
 		default:
 			panic("unreachable")
 		}
@@ -148,7 +157,7 @@ func walkBucketHealth(depth int, node key.Key, nodeTable, knownNodes *trie.Trie)
 }
 
 func bucketReportFromTries(depth int, actualBucket, maxBucket *trie.Trie) *BucketHealthReport {
-	actualKnown := trie.Intersect(actualBucket, maxBucket)
+	actualKnown := trie.IntersectAtDepth(depth, actualBucket, maxBucket)
 	actualKnownSize := actualKnown.Size()
 	return &BucketHealthReport{
 		Depth:                 depth,

kademlia/health_test.go

+package kademlia
+
+import (
+	"math/rand"
+	"testing"
+
+	"github.com/libp2p/go-libp2p-xor/key"
+)
+
+func TestTableHealthFromSets(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		s := randomTestTableHealthSubsetSamples(10, 100)
+		report := TableHealthFromSets(s.Node, s.Contacts, s.Known)
+		for _, b := range report.Bucket {
+			if b.ActualUnknownContacts != 0 {
+				t.Errorf("expecting no actual unknown contacts, got %d", b.ActualUnknownContacts)
+			}
+		}
+	}
+}
+
+func randomTestTableHealthSubsetSamples(contactSize, knownSize int) *testTableHealthSample {
+	known := make([]key.Key, knownSize)
+	for i := range known {
+		known[i] = randomKey(16)
+	}
+	contacts := make([]key.Key, contactSize)
+	perm := rand.Perm(knownSize)
+	for i := 0; i < contactSize; i++ {
+		contacts[i] = known[perm[i]]
+	}
+	return &testTableHealthSample{
+		Node:     randomKey(16),
+		Contacts: contacts,
+		Known:    known,
+	}
+}
+
+func randomKey(size int) key.Key {
+	k := make([]byte, size)
+	rand.Read(k)
+	return key.Key(k)
+}
+
+type testTableHealthSample struct {
+	Node     key.Key
+	Contacts []key.Key
+	Known    []key.Key
+}

trie/intersect_test.go

@@ -188,13 +188,4 @@ func testIntersectTrieFromJSON(srcJSON string) *testIntersectTrie {
 	return s
 }
 
-var testIntersectJSONTries = []string{
-	// 	`
-	// {
-	//     "LeftTrie": [
-	//     ],
-	//     "RightTrie": [
-	//     ]
-	// }
-	// 	`,
-}
+var testIntersectJSONTries = []string{}