From 32268a8135f04e087e0478da32e9f61e6fb95ea9 Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Sat, 28 Apr 2018 14:41:36 -0400
Subject: [PATCH] limit maxPexMessageSize based on maxAddressSize

---
 p2p/pex/pex_reactor.go | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/p2p/pex/pex_reactor.go b/p2p/pex/pex_reactor.go
index c6ae4f22d..dfe54e0d6 100644
--- a/p2p/pex/pex_reactor.go
+++ b/p2p/pex/pex_reactor.go
@@ -20,10 +20,14 @@ const (
 	// PexChannel is a channel for PEX messages
 	PexChannel = byte(0x00)
 
-	// TODO: make smaller. Should match the maxGetSelection
-	// this is basically the amplification factor since a request
-	// msg is like 1 byte ... it can cause us to send msgs of this size!
-	maxPexMessageSize = 1048576 // 1MB
+	// over-estimate of max NetAddress size
+	// hexID (40) + IP (16) + Port (2) + Name (100) ...
+	// NOTE: dont use massive DNS name ..
+	maxAddressSize = 256
+
+	// NOTE: amplificaiton factor!
+	// small request results in up to maxPexMessageSize response
+	maxPexMessageSize = maxAddressSize * maxGetSelection
 
 	// ensure we have enough peers
 	defaultEnsurePeersPeriod   = 30 * time.Second