Move replay into subpackage

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

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
-}

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
 			}
 

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
 	}
 

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)
 		}
 	}