This repository has been archived by the owner on Jun 20, 2024. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 663
/
mac_cache.go
111 lines (101 loc) · 2.27 KB
/
mac_cache.go
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
package router
import (
"bytes"
"fmt"
"net"
"sync"
"time"
)
type MacCacheEntry struct {
lastSeen time.Time
peer *Peer
}
type MacCache struct {
sync.RWMutex
table map[uint64]*MacCacheEntry
maxAge time.Duration
expiryTimer *time.Timer
onExpiry func(net.HardwareAddr, *Peer)
}
func NewMacCache(maxAge time.Duration, onExpiry func(net.HardwareAddr, *Peer)) *MacCache {
res := &MacCache{
table: make(map[uint64]*MacCacheEntry),
maxAge: maxAge,
onExpiry: onExpiry}
res.setExpiryTimer()
return res
}
func (cache *MacCache) Enter(mac net.HardwareAddr, peer *Peer) bool {
key := macint(mac)
now := time.Now()
cache.RLock()
entry, found := cache.table[key]
if found && entry.peer == peer && now.Before(entry.lastSeen.Add(cache.maxAge/10)) {
cache.RUnlock()
return false
} else {
cache.RUnlock()
}
cache.Lock()
defer cache.Unlock()
entry, found = cache.table[key]
if !found {
cache.table[key] = &MacCacheEntry{lastSeen: now, peer: peer}
return true
}
if entry.peer != peer {
entry.lastSeen = now
entry.peer = peer
return true
}
if now.After(entry.lastSeen.Add(cache.maxAge / 10)) {
entry.lastSeen = now
}
return false
}
func (cache *MacCache) Lookup(mac net.HardwareAddr) (*Peer, bool) {
key := macint(mac)
cache.RLock()
defer cache.RUnlock()
entry, found := cache.table[key]
if !found {
return nil, false
}
return entry.peer, true
}
func (cache *MacCache) Delete(peer *Peer) bool {
found := false
cache.Lock()
defer cache.Unlock()
for key, entry := range cache.table {
if entry.peer == peer {
delete(cache.table, key)
found = true
}
}
return found
}
func (cache *MacCache) String() string {
var buf bytes.Buffer
cache.RLock()
defer cache.RUnlock()
for key, entry := range cache.table {
buf.WriteString(fmt.Sprintf("%v -> %s (%v)\n", intmac(key), entry.peer.Name, entry.lastSeen))
}
return buf.String()
}
func (cache *MacCache) setExpiryTimer() {
cache.expiryTimer = time.AfterFunc(cache.maxAge/10, func() { cache.expire() })
}
func (cache *MacCache) expire() {
now := time.Now()
cache.Lock()
defer cache.Unlock()
for key, entry := range cache.table {
if now.After(entry.lastSeen.Add(cache.maxAge)) {
delete(cache.table, key)
cache.onExpiry(intmac(key), entry.peer)
}
}
cache.setExpiryTimer()
}