From 66ebf7c91ea383f115f06b5f9728906f6da2f9bb Mon Sep 17 00:00:00 2001
From: Kleissner <peter@kleissner.investments>
Date: Wed, 7 Jul 2021 02:50:12 +0200
Subject: [PATCH] New DHT function IsNodeContact to check if node is in local
 routing table

---
 Kademlia.go       | 12 ++++++++++++
 dht/DHT Lite.go   |  5 +++++
 dht/Hash Table.go | 16 ++++++++++------
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/Kademlia.go b/Kademlia.go
index 1e34970..c92a4e7 100644
--- a/Kademlia.go
+++ b/Kademlia.go
@@ -163,3 +163,15 @@ func StoreDataDHT(data []byte) error {
 	}
 	return nodesDHT.Store(key, uint64(len(data)))
 }
+
+// ---- NODE FUNCTIONS ----
+
+// IsNodeContact checks if the node is a contact in the local DHT routing table
+func IsNodeContact(nodeID []byte) (node *dht.Node, peer *PeerInfo) {
+	node = nodesDHT.IsNodeContact(nodeID)
+	if node == nil {
+		return nil, nil
+	}
+
+	return node, node.Info.(*PeerInfo)
+}
diff --git a/dht/DHT Lite.go b/dht/DHT Lite.go
index 20804fb..f0dd134 100644
--- a/dht/DHT Lite.go	
+++ b/dht/DHT Lite.go	
@@ -96,6 +96,11 @@ func (dht *DHT) IsNodeCloser(node1, node2 []byte) bool {
 	return iDist.Cmp(jDist) == -1
 }
 
+// IsNodeContact checks if the given node is in the local routing table
+func (dht *DHT) IsNodeContact(ID []byte) (node *Node) {
+	return dht.ht.doesNodeExist(ID)
+}
+
 // ---- Synchronous network query functions below ----
 
 // Store informs the network about data stored locally.
diff --git a/dht/Hash Table.go b/dht/Hash Table.go
index c3ea3b2..ae022fa 100644
--- a/dht/Hash Table.go	
+++ b/dht/Hash Table.go	
@@ -74,15 +74,19 @@ func (ht *hashTable) markNodeAsSeen(index int, ID []byte) {
 	ht.RoutingTable[index] = bucket
 }
 
-func (ht *hashTable) doesNodeExistInBucket(bucket int, node []byte) bool {
+func (ht *hashTable) doesNodeExistInBucket(bucket int, ID []byte) (node *Node) {
 	ht.mutex.RLock()
 	defer ht.mutex.RUnlock()
-	for _, v := range ht.RoutingTable[bucket] {
-		if bytes.Compare(v.ID, node) == 0 {
-			return true
+	for _, node = range ht.RoutingTable[bucket] {
+		if bytes.Compare(node.ID, ID) == 0 {
+			return node
 		}
 	}
-	return false
+	return nil
+}
+
+func (ht *hashTable) doesNodeExist(ID []byte) (node *Node) {
+	return ht.doesNodeExistInBucket(ht.getBucketIndexFromDifferingBit(ID), ID)
 }
 
 // getClosestContacts returns the closest nodes to the target. filterFunc is optional and allows the caller to filter the nodes.
@@ -140,7 +144,7 @@ func (ht *hashTable) insertNode(node *Node, shouldEvict func(nodeOld *Node, node
 	index := ht.getBucketIndexFromDifferingBit(node.ID)
 
 	// If the node already exist, mark it as seen
-	if ht.doesNodeExistInBucket(index, node.ID) {
+	if ht.doesNodeExistInBucket(index, node.ID) != nil {
 		ht.markNodeAsSeen(index, node.ID)
 		return
 	}