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
|
package kcp
import (
"sync"
"time"
)
var (
// BlacklistDuration sets a duration for which a session is blacklisted
// once it's established. This is simillar to TIME_WAIT state in TCP, whereby
// any connection attempt with the same session parameters is ignored for
// some amount of time.
//
// This is only useful when dial attempts happen from a pre-determined port,
// for example when you are dialing from the same connection you are listening on
// to punch through NAT, and helps with the fact that KCP is state-less.
// This helps better deal with scenarios where a process on one of the side (A)
// get's restarted, and stray packets from other side (B) makes it look like
// as if someone is trying to connect to A. Even if session dies on B,
// new stray reply packets from A resurrect the session on B, causing the
// session to be alive forever.
BlacklistDuration time.Duration
blacklist = blacklistMap{
entries: make(map[sessionKey]int64),
}
)
// a global map for blacklisting conversations
type blacklistMap struct {
entries map[sessionKey]int64
mut sync.RWMutex
}
func (m *blacklistMap) add(address string, conv uint32) {
if BlacklistDuration == 0 {
return
}
timeout := time.Now().Add(BlacklistDuration).UnixNano()
m.mut.Lock()
m.entries[sessionKey{
addr: address,
convID: conv,
}] = timeout
m.reap()
m.mut.Unlock()
}
func (m *blacklistMap) has(address string, conv uint32) bool {
if BlacklistDuration == 0 {
return false
}
m.mut.RLock()
t, ok := m.entries[sessionKey{
addr: address,
convID: conv,
}]
m.mut.RUnlock()
return ok && t > time.Now().UnixNano()
}
func (m *blacklistMap) reap() {
now := time.Now().UnixNano()
for k, t := range m.entries {
if t < now {
delete(m.entries, k)
}
}
}
|
