From 9bedd7720c1667e249c6735eb10e49d78ca4c723 Mon Sep 17 00:00:00 2001
From: David Hill <dhill@mindcry.org>
Date: Sat, 19 Nov 2016 11:19:51 -0500
Subject: [PATCH] btcd: only allow one getaddr request per peer

---
 server.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/server.go b/server.go
index 1bed7e26..7ba594e1 100644
--- a/server.go
+++ b/server.go
@@ -213,6 +213,7 @@ type serverPeer struct {
 	continueHash    *chainhash.Hash
 	relayMtx        sync.Mutex
 	disableRelayTx  bool
+	sentAddrs       bool
 	requestQueue    []*wire.InvVect
 	requestedTxns   map[chainhash.Hash]struct{}
 	requestedBlocks map[chainhash.Hash]struct{}
@@ -892,9 +893,20 @@ func (sp *serverPeer) OnGetAddr(_ *peer.Peer, msg *wire.MsgGetAddr) {
 	// Do not accept getaddr requests from outbound peers.  This reduces
 	// fingerprinting attacks.
 	if !sp.Inbound() {
+		peerLog.Debugf("Ignoring getaddr request from outbound peer ",
+			"%v", sp)
 		return
 	}
 
+	// Only allow one getaddr request per connection to discourage
+	// address stamping of inv announcements.
+	if sp.sentAddrs {
+		peerLog.Debugf("Ignoring repeated getaddr request from peer ",
+			"%v", sp)
+		return
+	}
+	sp.sentAddrs = true
+
 	// Get the current known addresses from the address manager.
 	addrCache := sp.server.addrManager.AddressCache()