From ced66e4eb5498014866f8fda242b62fb5b55009b Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Thu, 17 Dec 2020 12:35:06 +0400
Subject: [PATCH] config: increase MaxPacketMsgPayloadSize to 1400

The MTU (Maximum Transmission Unit) for Ethernet is 1500 bytes.
The IP header and the TCP header take up 20 bytes each at least (unless
optional header fields are used) and thus the max for (non-Jumbo frame)
Ethernet is 1500 - 20 -20 = 1460
Source: https://stackoverflow.com/a/3074427/820520
---
 config/config.go       | 23 ++++++++++++++---------
 p2p/conn/connection.go |  3 ++-
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/config/config.go b/config/config.go
index 58187f1db..26b2a5d97 100644
--- a/config/config.go
+++ b/config/config.go
@@ -561,15 +561,20 @@ func DefaultP2PConfig() *P2PConfig {
 		MaxNumOutboundPeers:          10,
 		PersistentPeersMaxDialPeriod: 0 * time.Second,
 		FlushThrottleTimeout:         100 * time.Millisecond,
-		MaxPacketMsgPayloadSize:      1024,    // 1 kB
-		SendRate:                     5120000, // 5 mB/s
-		RecvRate:                     5120000, // 5 mB/s
-		PexReactor:                   true,
-		SeedMode:                     false,
-		AllowDuplicateIP:             false,
-		HandshakeTimeout:             20 * time.Second,
-		DialTimeout:                  3 * time.Second,
-		TestDialFail:                 false,
+		// The MTU (Maximum Transmission Unit) for Ethernet is 1500 bytes.
+		// The IP header and the TCP header take up 20 bytes each at least (unless
+		// optional header fields are used) and thus the max for (non-Jumbo frame)
+		// Ethernet is 1500 - 20 -20 = 1460
+		// Source: https://stackoverflow.com/a/3074427/820520
+		MaxPacketMsgPayloadSize: 1400,
+		SendRate:                5120000, // 5 mB/s
+		RecvRate:                5120000, // 5 mB/s
+		PexReactor:              true,
+		SeedMode:                false,
+		AllowDuplicateIP:        false,
+		HandshakeTimeout:        20 * time.Second,
+		DialTimeout:             3 * time.Second,
+		TestDialFail:            false,
 	}
 }
 
diff --git a/p2p/conn/connection.go b/p2p/conn/connection.go
index e2c5fe1a7..e6455b0cf 100644
--- a/p2p/conn/connection.go
+++ b/p2p/conn/connection.go
@@ -25,7 +25,8 @@ import (
 )
 
 const (
-	defaultMaxPacketMsgPayloadSize = 1024
+	// mirrors MaxPacketMsgPayloadSize from config/config.go
+	defaultMaxPacketMsgPayloadSize = 1400
 
 	numBatchPacketMsgs = 10
 	minReadBufferSize  = 1024