blob: a1dea61a99c8049b445978dbf353b66df92dbb06 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2020 WireGuard LLC. All Rights Reserved.
*/
package ratelimiter
import (
"net"
"sync"
"time"
)
const (
packetsPerSecond = 20
packetsBurstable = 5
garbageCollectTime = time.Second
packetCost = 1000000000 / packetsPerSecond
maxTokens = packetCost * packetsBurstable
)
type RatelimiterEntry struct {
mu sync.Mutex
lastTime time.Time
tokens int64
}
type Ratelimiter struct {
mu sync.RWMutex
timeNow func() time.Time
stopReset chan struct{} // send to reset, close to stop
tableIPv4 map[[net.IPv4len]byte]*RatelimiterEntry
tableIPv6 map[[net.IPv6len]byte]*RatelimiterEntry
}
func (rate *Ratelimiter) Close() {
rate.mu.Lock()
defer rate.mu.Unlock()
if rate.stopReset != nil {
close(rate.stopReset)
}
}
func (rate *Ratelimiter) Init() {
rate.mu.Lock()
defer rate.mu.Unlock()
if rate.timeNow == nil {
rate.timeNow = time.Now
}
// stop any ongoing garbage collection routine
if rate.stopReset != nil {
close(rate.stopReset)
}
rate.stopReset = make(chan struct{})
rate.tableIPv4 = make(map[[net.IPv4len]byte]*RatelimiterEntry)
rate.tableIPv6 = make(map[[net.IPv6len]byte]*RatelimiterEntry)
stopReset := rate.stopReset // store in case Init is called again.
// Start garbage collection routine.
go func() {
ticker := time.NewTicker(time.Second)
ticker.Stop()
for {
select {
case _, ok := <-stopReset:
ticker.Stop()
if !ok {
return
}
ticker = time.NewTicker(time.Second)
case <-ticker.C:
if rate.cleanup() {
ticker.Stop()
}
}
}
}()
}
func (rate *Ratelimiter) cleanup() (empty bool) {
rate.mu.Lock()
defer rate.mu.Unlock()
for key, entry := range rate.tableIPv4 {
entry.mu.Lock()
if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
delete(rate.tableIPv4, key)
}
entry.mu.Unlock()
}
for key, entry := range rate.tableIPv6 {
entry.mu.Lock()
if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
delete(rate.tableIPv6, key)
}
entry.mu.Unlock()
}
return len(rate.tableIPv4) == 0 && len(rate.tableIPv6) == 0
}
func (rate *Ratelimiter) Allow(ip net.IP) bool {
var entry *RatelimiterEntry
var keyIPv4 [net.IPv4len]byte
var keyIPv6 [net.IPv6len]byte
// lookup entry
IPv4 := ip.To4()
IPv6 := ip.To16()
rate.mu.RLock()
if IPv4 != nil {
copy(keyIPv4[:], IPv4)
entry = rate.tableIPv4[keyIPv4]
} else {
copy(keyIPv6[:], IPv6)
entry = rate.tableIPv6[keyIPv6]
}
rate.mu.RUnlock()
// make new entry if not found
if entry == nil {
entry = new(RatelimiterEntry)
entry.tokens = maxTokens - packetCost
entry.lastTime = rate.timeNow()
rate.mu.Lock()
if IPv4 != nil {
rate.tableIPv4[keyIPv4] = entry
if len(rate.tableIPv4) == 1 && len(rate.tableIPv6) == 0 {
rate.stopReset <- struct{}{}
}
} else {
rate.tableIPv6[keyIPv6] = entry
if len(rate.tableIPv6) == 1 && len(rate.tableIPv4) == 0 {
rate.stopReset <- struct{}{}
}
}
rate.mu.Unlock()
return true
}
// add tokens to entry
entry.mu.Lock()
now := rate.timeNow()
entry.tokens += now.Sub(entry.lastTime).Nanoseconds()
entry.lastTime = now
if entry.tokens > maxTokens {
entry.tokens = maxTokens
}
// subtract cost of packet
if entry.tokens > packetCost {
entry.tokens -= packetCost
entry.mu.Unlock()
return true
}
entry.mu.Unlock()
return false
}
|
