-
Notifications
You must be signed in to change notification settings - Fork 10
/
direct_udp.go
174 lines (149 loc) · 4.22 KB
/
direct_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
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
173
174
package easyss
import (
"fmt"
"net"
"strconv"
"time"
"github.com/nange/easyss/v2/log"
"github.com/nange/easyss/v2/util/bytespool"
"github.com/txthinking/socks5"
"github.com/xjasonlyu/tun2socks/v2/dialer"
)
// DefaultDirectDNSServers the servers are dns servers from tencent, aliyun and baidu
var DefaultDirectDNSServers = [3]string{"119.29.29.29:53", "223.5.5.5:53", "180.76.76.76:53"}
var DefaultDNSServerDomains = [3]string{"dnspod.cn", "alidns.com", "dudns.baidu.com"}
const DirectSuffix = "direct"
// DirectUDPExchange used to store client address and remote connection
type DirectUDPExchange struct {
ClientAddr *net.UDPAddr
RemoteConn net.PacketConn
}
func (ss *Easyss) directUDPRelay(s *socks5.Server, laddr *net.UDPAddr, d *socks5.Datagram, isDNSReq bool) error {
logPrefix := "[UDP_DIRECT]"
if isDNSReq {
logPrefix = "[DNS_DIRECT]"
}
var ch chan struct{}
var hasAssoc bool
portStr := strconv.FormatInt(int64(laddr.Port), 10)
asCh, ok := s.AssociatedUDP.Get(portStr)
if ok {
hasAssoc = true
ch = asCh.(chan struct{})
log.Debug(logPrefix+" found the associate with tcp", "src", laddr.String(), "dst", d.Address())
} else {
log.Debug(logPrefix+" the udp addr doesn't associate with tcp", logPrefix, "udp_addr", laddr.String(), "dst_addr", d.Address())
}
dst := d.Address()
rewrittenDst := dst
if isDNSReq {
rewrittenDst = ss.DirectDNSServer()
}
log.Info(logPrefix, "target", rewrittenDst)
uAddr, _ := net.ResolveUDPAddr("udp", rewrittenDst)
send := func(ue *DirectUDPExchange, data []byte, addr net.Addr) error {
select {
case <-ch:
return fmt.Errorf("this udp address %s is not associated with tcp", ue.ClientAddr.String())
default:
_, err := ue.RemoteConn.WriteTo(data, addr)
if err != nil {
return err
}
log.Debug(logPrefix+" sent data", "from", ue.ClientAddr.String(), "to", addr.String())
}
return nil
}
var ue *DirectUDPExchange
var src = laddr.String()
var exchKey = src + dst + DirectSuffix
ss.lockKey(exchKey)
defer ss.unlockKey(exchKey)
iue, ok := s.UDPExchanges.Get(exchKey)
if ok {
ue = iue.(*DirectUDPExchange)
return send(ue, d.Data, uAddr)
}
pc, err := ss.directUDPConn()
if err != nil {
log.Error(logPrefix+" listen packet", "err", err)
return err
}
ue = &DirectUDPExchange{
ClientAddr: laddr,
RemoteConn: pc,
}
if err := send(ue, d.Data, uAddr); err != nil {
log.Warn(logPrefix+" send data", "to", uAddr.String(), "err", err)
return err
}
s.UDPExchanges.Set(exchKey, ue, -1)
go func() {
var buf = bytespool.Get(MaxUDPDataSize)
defer func() {
ss.lockKey(exchKey)
defer ss.unlockKey(exchKey)
bytespool.MustPut(buf)
s.UDPExchanges.Delete(exchKey)
ue.RemoteConn.Close()
}()
for {
select {
case <-ch:
log.Info(logPrefix+" the tcp that udp address associated closed", "udp_address", ue.ClientAddr.String())
return
default:
}
if !hasAssoc {
var err error
if isDNSReq {
err = ue.RemoteConn.SetDeadline(time.Now().Add(DefaultDNSTimeout))
} else {
err = ue.RemoteConn.SetDeadline(time.Now().Add(ss.Timeout()))
}
if err != nil {
log.Error(logPrefix+" set the deadline for remote conn", "err", err)
return
}
}
n, _, err := ue.RemoteConn.ReadFrom(buf)
if err != nil {
return
}
log.Debug(logPrefix+" got data from remote", "client", ue.ClientAddr.String(), "data_len", len(buf[0:n]))
// if is dns response, set result to dns cache
_msg := ss.SetDNSCacheIfNeeded(buf[0:n], true)
a, addr, port, err := socks5.ParseAddress(dst)
if err != nil {
log.Error(logPrefix+" parse dst address", "err", err)
return
}
data := buf[0:n]
if _msg != nil {
data, _ = _msg.Pack()
}
d1 := socks5.NewDatagram(a, addr, port, data)
if _, err := s.UDPConn.WriteToUDP(d1.Bytes(), laddr); err != nil {
return
}
}
}()
return nil
}
func (ss *Easyss) directUDPConn() (net.PacketConn, error) {
var pc net.PacketConn
var err error
network := "udp"
if ss.ShouldIPV6Disable() {
network = "udp4"
}
if ss.EnabledTun2socks() {
pc, err = dialer.ListenPacketWithOptions(network, "", &dialer.Options{
InterfaceName: ss.LocalDevice(),
InterfaceIndex: ss.LocalDeviceIndex(),
})
} else {
pc, err = net.ListenPacket(network, "")
}
return pc, err
}