From 86d51fa1cb9d7a43faa42689ba8e1bddd7f40e09 Mon Sep 17 00:00:00 2001
From: stasatdaglabs <39559713+stasatdaglabs@users.noreply.github.com>
Date: Mon, 24 Aug 2020 16:11:32 +0300
Subject: [PATCH] [NOD-1307] Fix duplicate connections (#897)

* [NOD-1307] Lock peersMutex in methods that don't.

* [NOD-1307] Fix duplicate connections.

* [NOD-1307] Use RLock instead of Lock.

* [NOD-1307] Simplify IsEqual.
---
 app/protocol/flowcontext/flow_context.go   |  4 ++--
 app/protocol/flowcontext/ibd.go            |  6 ++++++
 app/protocol/flowcontext/network.go        |  6 +++---
 infrastructure/network/netadapter/id/id.go | 11 +++++------
 4 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/app/protocol/flowcontext/flow_context.go b/app/protocol/flowcontext/flow_context.go
index fa75e303e..4086b0615 100644
--- a/app/protocol/flowcontext/flow_context.go
+++ b/app/protocol/flowcontext/flow_context.go
@@ -39,7 +39,7 @@ type FlowContext struct {
 	startIBDMutex sync.Mutex
 	ibdPeer       *peerpkg.Peer
 
-	peers      map[*id.ID]*peerpkg.Peer
+	peers      map[id.ID]*peerpkg.Peer
 	peersMutex sync.RWMutex
 }
 
@@ -57,7 +57,7 @@ func New(cfg *config.Config, dag *blockdag.BlockDAG, addressManager *addressmana
 		txPool:                      txPool,
 		sharedRequestedTransactions: relaytransactions.NewSharedRequestedTransactions(),
 		sharedRequestedBlocks:       blockrelay.NewSharedRequestedBlocks(),
-		peers:                       make(map[*id.ID]*peerpkg.Peer),
+		peers:                       make(map[id.ID]*peerpkg.Peer),
 		transactionsToRebroadcast:   make(map[daghash.TxID]*util.Tx),
 	}
 }
diff --git a/app/protocol/flowcontext/ibd.go b/app/protocol/flowcontext/ibd.go
index 19b5eb9de..63ce09d56 100644
--- a/app/protocol/flowcontext/ibd.go
+++ b/app/protocol/flowcontext/ibd.go
@@ -37,6 +37,9 @@ func (f *FlowContext) IsInIBD() bool {
 // selectPeerForIBD returns the first peer whose selected tip
 // hash is not in our DAG
 func (f *FlowContext) selectPeerForIBD(dag *blockdag.BlockDAG) *peerpkg.Peer {
+	f.peersMutex.RLock()
+	defer f.peersMutex.RUnlock()
+
 	for _, peer := range f.peers {
 		peerSelectedTipHash := peer.SelectedTipHash()
 		if !dag.IsInDAG(peerSelectedTipHash) {
@@ -59,6 +62,9 @@ func (f *FlowContext) isDAGTimeCurrent() bool {
 }
 
 func (f *FlowContext) requestSelectedTips() {
+	f.peersMutex.RLock()
+	defer f.peersMutex.RUnlock()
+
 	for _, peer := range f.peers {
 		peer.RequestSelectedTipIfRequired()
 	}
diff --git a/app/protocol/flowcontext/network.go b/app/protocol/flowcontext/network.go
index 922c24fa1..d0dca1697 100644
--- a/app/protocol/flowcontext/network.go
+++ b/app/protocol/flowcontext/network.go
@@ -24,11 +24,11 @@ func (f *FlowContext) AddToPeers(peer *peerpkg.Peer) error {
 	f.peersMutex.Lock()
 	defer f.peersMutex.Unlock()
 
-	if _, ok := f.peers[peer.ID()]; ok {
+	if _, ok := f.peers[*peer.ID()]; ok {
 		return errors.Wrapf(common.ErrPeerWithSameIDExists, "peer with ID %s already exists", peer.ID())
 	}
 
-	f.peers[peer.ID()] = peer
+	f.peers[*peer.ID()] = peer
 
 	return nil
 }
@@ -38,7 +38,7 @@ func (f *FlowContext) RemoveFromPeers(peer *peerpkg.Peer) {
 	f.peersMutex.Lock()
 	defer f.peersMutex.Unlock()
 
-	delete(f.peers, peer.ID())
+	delete(f.peers, *peer.ID())
 }
 
 // readyPeerConnections returns the NetConnections of all the ready peers.
diff --git a/infrastructure/network/netadapter/id/id.go b/infrastructure/network/netadapter/id/id.go
index b55e5df74..93b350cdf 100644
--- a/infrastructure/network/netadapter/id/id.go
+++ b/infrastructure/network/netadapter/id/id.go
@@ -12,7 +12,7 @@ const IDLength = 16
 
 // ID identifies a network connection
 type ID struct {
-	bytes []byte
+	bytes [IDLength]byte
 }
 
 // GenerateID generates a new ID
@@ -27,23 +27,22 @@ func GenerateID() (*ID, error) {
 
 // IsEqual returns whether id equals to other.
 func (id *ID) IsEqual(other *ID) bool {
-	return bytes.Equal(id.bytes, other.bytes)
+	return *id == *other
 }
 
 func (id *ID) String() string {
-	return hex.EncodeToString(id.bytes)
+	return hex.EncodeToString(id.bytes[:])
 }
 
 // Deserialize decodes a block from r into the receiver.
 func (id *ID) Deserialize(r io.Reader) error {
-	id.bytes = make([]byte, IDLength)
-	_, err := io.ReadFull(r, id.bytes)
+	_, err := io.ReadFull(r, id.bytes[:])
 	return err
 }
 
 // Serialize serializes the receiver into the given writer.
 func (id *ID) Serialize(w io.Writer) error {
-	_, err := w.Write(id.bytes)
+	_, err := w.Write(id.bytes[:])
 	return err
 }