/
udp.go
147 lines (121 loc) · 2.47 KB
/
udp.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
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
package chclient
import (
"io"
"net"
"sync"
"time"
"github.com/openrport/openrport/share/comm"
"github.com/openrport/openrport/share/logger"
)
const activeConnectionTimeout = 15 * time.Second
type udpHandler struct {
*logger.Logger
addr string
channel *comm.UDPChannel
mtx sync.Mutex
conns map[string]net.Conn
lastActive map[string]time.Time
}
func newUDPHandler(logger *logger.Logger, addr string) *udpHandler {
return &udpHandler{
Logger: logger,
addr: addr,
conns: make(map[string]net.Conn),
lastActive: make(map[string]time.Time),
}
}
func (h *udpHandler) Handle(stream io.ReadWriteCloser) error {
defer stream.Close()
h.channel = comm.NewUDPChannel(stream)
for {
id, data, err := h.channel.Decode()
if err == io.EOF {
return nil
}
if err != nil {
return err
}
conn, err := h.getConn(id)
if err != nil {
return err
}
h.setActive(id)
_, err = conn.Write(data)
if err != nil {
return err
}
}
}
func (h *udpHandler) getConn(id *net.UDPAddr) (net.Conn, error) {
h.mtx.Lock()
defer h.mtx.Unlock()
idStr := id.String()
conn, ok := h.conns[idStr]
if ok {
return conn, nil
}
conn, err := net.Dial("udp", h.addr)
if err != nil {
return nil, err
}
go func() {
err := h.receive(id, conn)
if err != nil {
h.Errorf("Error in receive: %v", err)
}
}()
h.conns[idStr] = conn
return conn, nil
}
func (h *udpHandler) close(id string) {
h.mtx.Lock()
defer h.mtx.Unlock()
conn, ok := h.conns[id]
if !ok {
return
}
h.Debugf("Closing connection for client: %v", id)
conn.Close()
delete(h.conns, id)
}
func (h *udpHandler) receive(id *net.UDPAddr, conn net.Conn) error {
defer h.close(id.String())
const maxMTU = 9012
buff := make([]byte, maxMTU)
for h.isActive(id) {
err := conn.SetReadDeadline(time.Now().Add(time.Second))
if err != nil {
return err
}
n, err := conn.Read(buff)
if e, ok := err.(net.Error); ok && (e.Timeout() || e.Temporary()) {
continue
}
if err == io.EOF {
return nil
}
if err != nil {
return err
}
h.setActive(id)
err = h.channel.Encode(id, buff[:n])
if err != nil {
return err
}
}
return nil
}
func (h *udpHandler) isActive(id *net.UDPAddr) bool {
h.mtx.Lock()
defer h.mtx.Unlock()
la, ok := h.lastActive[id.String()]
if !ok {
return true
}
return time.Since(la) < activeConnectionTimeout
}
func (h *udpHandler) setActive(id *net.UDPAddr) {
h.mtx.Lock()
defer h.mtx.Unlock()
h.lastActive[id.String()] = time.Now()
}