Removed exported methods from ratelimiter package

internal/ratelimiter/ratelimiter.go

@@ -2,8 +2,7 @@ package ratelimiter
 
 /* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
 
-/* This file contains a port of the ratelimited from the linux kernel version
- */
+/* This file contains a port of the rate-limiter from the linux kernel version */
 
 import (
 	"net"
@@ -12,11 +11,11 @@ import (
 )
 
 const (
-	RatelimiterPacketsPerSecond   = 20
-	RatelimiterPacketsBurstable   = 5
-	RatelimiterGarbageCollectTime = time.Second
-	RatelimiterPacketCost         = 1000000000 / RatelimiterPacketsPerSecond
-	RatelimiterMaxTokens          = RatelimiterPacketCost * RatelimiterPacketsBurstable
+	packetsPerSecond   = 20
+	packetsBurstable   = 5
+	garbageCollectTime = time.Second
+	packetCost         = 1000000000 / packetsPerSecond
+	maxTokens          = packetCost * packetsBurstable
 )
 
 type RatelimiterEntry struct {
@@ -45,6 +44,8 @@ func (rate *Ratelimiter) Init() {
 	rate.mutex.Lock()
 	defer rate.mutex.Unlock()
 
+	// stop any ongoing garbage collection routine
+
 	if rate.stop != nil {
 		close(rate.stop)
 	}
@@ -53,6 +54,8 @@ func (rate *Ratelimiter) Init() {
 	rate.tableIPv4 = make(map[[net.IPv4len]byte]*RatelimiterEntry)
 	rate.tableIPv6 = make(map[[net.IPv6len]byte]*RatelimiterEntry)
 
+	// start garbage collection routine
+
 	go func() {
 		timer := time.NewTimer(time.Second)
 		for {
@@ -60,39 +63,32 @@ func (rate *Ratelimiter) Init() {
 			case <-rate.stop:
 				return
 			case <-timer.C:
-				rate.garbageCollectEntries()
+				func() {
+					rate.mutex.Lock()
+					defer rate.mutex.Unlock()
+
+					for key, entry := range rate.tableIPv4 {
+						entry.mutex.Lock()
+						if time.Now().Sub(entry.lastTime) > garbageCollectTime {
+							delete(rate.tableIPv4, key)
+						}
+						entry.mutex.Unlock()
+					}
+
+					for key, entry := range rate.tableIPv6 {
+						entry.mutex.Lock()
+						if time.Now().Sub(entry.lastTime) > garbageCollectTime {
+							delete(rate.tableIPv6, key)
+						}
+						entry.mutex.Unlock()
+					}
+				}()
 				timer.Reset(time.Second)
 			}
 		}
 	}()
 }
 
-func (rate *Ratelimiter) garbageCollectEntries() {
-	rate.mutex.Lock()
-
-	// remove unused IPv4 entries
-
-	for key, entry := range rate.tableIPv4 {
-		entry.mutex.Lock()
-		if time.Now().Sub(entry.lastTime) > RatelimiterGarbageCollectTime {
-			delete(rate.tableIPv4, key)
-		}
-		entry.mutex.Unlock()
-	}
-
-	// remove unused IPv6 entries
-
-	for key, entry := range rate.tableIPv6 {
-		entry.mutex.Lock()
-		if time.Now().Sub(entry.lastTime) > RatelimiterGarbageCollectTime {
-			delete(rate.tableIPv6, key)
-		}
-		entry.mutex.Unlock()
-	}
-
-	rate.mutex.Unlock()
-}
-
 func (rate *Ratelimiter) Allow(ip net.IP) bool {
 	var entry *RatelimiterEntry
 	var KeyIPv4 [net.IPv4len]byte
@@ -120,7 +116,7 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 	if entry == nil {
 		rate.mutex.Lock()
 		entry = new(RatelimiterEntry)
-		entry.tokens = RatelimiterMaxTokens - RatelimiterPacketCost
+		entry.tokens = maxTokens - packetCost
 		entry.lastTime = time.Now()
 		if IPv4 != nil {
 			rate.tableIPv4[KeyIPv4] = entry
@@ -137,14 +133,14 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 	now := time.Now()
 	entry.tokens += now.Sub(entry.lastTime).Nanoseconds()
 	entry.lastTime = now
-	if entry.tokens > RatelimiterMaxTokens {
-		entry.tokens = RatelimiterMaxTokens
+	if entry.tokens > maxTokens {
+		entry.tokens = maxTokens
 	}
 
 	// subtract cost of packet
 
-	if entry.tokens > RatelimiterPacketCost {
-		entry.tokens -= RatelimiterPacketCost
+	if entry.tokens > packetCost {
+		entry.tokens -= packetCost
 		entry.mutex.Unlock()
 		return true
 	}