From 5a2228a5c910ada948677f1dd3fcc59f74e5cb20 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 23 May 2018 02:32:02 +0200
Subject: [PATCH] Move replay into subpackage

---
 keypair.go                              |  3 ++-
 misc.go                                 |  7 -------
 receive.go                              |  2 +-
 replay.go => replay/replay.go           | 15 ++++++++++-----
 replay_test.go => replay/replay_test.go |  6 ++++--
 5 files changed, 17 insertions(+), 16 deletions(-)
 rename replay.go => replay/replay.go (89%)
 rename replay_test.go => replay/replay_test.go (95%)

diff --git a/keypair.go b/keypair.go
index be7600b..face310 100644
--- a/keypair.go
+++ b/keypair.go
@@ -7,6 +7,7 @@
 package main
 
 import (
+	"./replay"
 	"crypto/cipher"
 	"sync"
 	"time"
@@ -23,7 +24,7 @@ type Keypair struct {
 	sendNonce    uint64
 	send         cipher.AEAD
 	receive      cipher.AEAD
-	replayFilter ReplayFilter
+	replayFilter replay.ReplayFilter
 	isInitiator  bool
 	created      time.Time
 	localIndex   uint32
diff --git a/misc.go b/misc.go
index af61718..ede94f9 100644
--- a/misc.go
+++ b/misc.go
@@ -47,10 +47,3 @@ func min(a, b uint) uint {
 	}
 	return a
 }
-
-func minUint64(a uint64, b uint64) uint64 {
-	if a > b {
-		return b
-	}
-	return a
-}
diff --git a/receive.go b/receive.go
index 3d9710c..707b056 100644
--- a/receive.go
+++ b/receive.go
@@ -544,7 +544,7 @@ func (peer *Peer) RoutineSequentialReceiver() {
 
 			// check for replay
 
-			if !elem.keypair.replayFilter.ValidateCounter(elem.counter) {
+			if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
 				continue
 			}
 
diff --git a/replay.go b/replay/replay.go
similarity index 89%
rename from replay.go
rename to replay/replay.go
index 2d9c6e1..993ff58 100644
--- a/replay.go
+++ b/replay/replay.go
@@ -4,9 +4,7 @@
  * Copyright (C) 2017-2018 Mathias N. Hall-Andersen <mathias@hall-andersen.dk>.
  */
 
-package main
-
-/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
+package replay
 
 /* Implementation of RFC6479
  * https://tools.ietf.org/html/rfc6479
@@ -32,6 +30,13 @@ const (
 	BacktrackWords = CounterBitsTotal / _WordSize
 )
 
+func minUint64(a uint64, b uint64) uint64 {
+	if a > b {
+		return b
+	}
+	return a
+}
+
 type ReplayFilter struct {
 	counter   uint64
 	backtrack [BacktrackWords]uintptr
@@ -42,8 +47,8 @@ func (filter *ReplayFilter) Init() {
 	filter.backtrack[0] = 0
 }
 
-func (filter *ReplayFilter) ValidateCounter(counter uint64) bool {
-	if counter >= RejectAfterMessages {
+func (filter *ReplayFilter) ValidateCounter(counter uint64, limit uint64) bool {
+	if counter >= limit {
 		return false
 	}
 
diff --git a/replay_test.go b/replay/replay_test.go
similarity index 95%
rename from replay_test.go
rename to replay/replay_test.go
index 8b2e57d..da39498 100644
--- a/replay_test.go
+++ b/replay/replay_test.go
@@ -4,7 +4,7 @@
  * Copyright (C) 2017-2018 Mathias N. Hall-Andersen <mathias@hall-andersen.dk>.
  */
 
-package main
+package replay
 
 import (
 	"testing"
@@ -15,6 +15,8 @@ import (
  *
  */
 
+const RejectAfterMessages = (1 << 64) - (1 << 4) - 1
+
 func TestReplay(t *testing.T) {
 	var filter ReplayFilter
 
@@ -23,7 +25,7 @@ func TestReplay(t *testing.T) {
 	testNumber := 0
 	T := func(n uint64, v bool) {
 		testNumber++
-		if filter.ValidateCounter(n) != v {
+		if filter.ValidateCounter(n, RejectAfterMessages) != v {
 			t.Fatal("Test", testNumber, "failed", n, v)
 		}
 	}