forked from valyala/fasthttp
/
tcpdialer.go
172 lines (150 loc) · 3.41 KB
/
tcpdialer.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
package fasthttp
import (
"net"
"strconv"
"sync"
"sync/atomic"
"time"
)
var (
dial = (&tcpDialer{}).NewDial()
dialDualStack = (&tcpDialer{DualStack: true}).NewDial()
)
// Dial dials the given TCP addr using tcp4.
//
// This dialer is intended for custom code wrapping before passing
// to Client.Dial or HostClient.Dial.
//
// For instance, per-host counters and/or limits may be implemented
// by such wrappers.
//
// The addr passed to the function must contain port. Example addr values:
//
// * foobar.baz:443
// * foo.bar:80
// * aaa.com:8080
func Dial(addr string) (net.Conn, error) {
return dial(addr)
}
// DialDualStack dials the given TCP addr using both tcp4 and tcp6.
//
// This dialer is intended for custom code wrapping before passing
// to Client.Dial or HostClient.Dial.
//
// For instance, per-host counters and/or limits may be implemented
// by such wrappers.
//
// The addr passed to the function must contain port. Example addr values:
//
// * foobar.baz:443
// * foo.bar:80
// * aaa.com:8080
func DialDualStack(addr string) (net.Conn, error) {
return dialDualStack(addr)
}
type tcpDialer struct {
DualStack bool
tcpAddrsLock sync.Mutex
tcpAddrsMap map[string]*tcpAddrEntry
}
func (d *tcpDialer) NewDial() DialFunc {
if d.tcpAddrsMap != nil {
panic("BUG: NewDial() already called")
}
d.tcpAddrsMap = make(map[string]*tcpAddrEntry)
go d.tcpAddrsClean()
return func(addr string) (net.Conn, error) {
tcpAddr, err := d.getTCPAddr(addr)
if err != nil {
return nil, err
}
network := "tcp4"
if d.DualStack {
network = "tcp"
}
return net.DialTCP(network, nil, tcpAddr)
}
}
type tcpAddrEntry struct {
addrs []net.TCPAddr
addrsIdx uint32
resolveTime time.Time
pending bool
}
var tcpAddrsCacheDuration = time.Minute
func (d *tcpDialer) tcpAddrsClean() {
expireDuration := 2 * tcpAddrsCacheDuration
for {
time.Sleep(time.Second)
t := time.Now()
d.tcpAddrsLock.Lock()
for k, e := range d.tcpAddrsMap {
if t.Sub(e.resolveTime) > expireDuration {
delete(d.tcpAddrsMap, k)
}
}
d.tcpAddrsLock.Unlock()
}
}
func (d *tcpDialer) getTCPAddr(addr string) (*net.TCPAddr, error) {
d.tcpAddrsLock.Lock()
e := d.tcpAddrsMap[addr]
if e != nil && !e.pending && time.Since(e.resolveTime) > tcpAddrsCacheDuration {
e.pending = true
e = nil
}
d.tcpAddrsLock.Unlock()
if e == nil {
tcpAddrs, err := resolveTCPAddrs(addr, d.DualStack)
if err != nil {
d.tcpAddrsLock.Lock()
e = d.tcpAddrsMap[addr]
if e != nil && e.pending {
e.pending = false
}
d.tcpAddrsLock.Unlock()
return nil, err
}
e = &tcpAddrEntry{
addrs: tcpAddrs,
resolveTime: time.Now(),
}
d.tcpAddrsLock.Lock()
d.tcpAddrsMap[addr] = e
d.tcpAddrsLock.Unlock()
}
tcpAddr := &e.addrs[0]
n := len(e.addrs)
if n > 1 {
n := atomic.AddUint32(&e.addrsIdx, 1)
tcpAddr = &e.addrs[n%uint32(n)]
}
return tcpAddr, nil
}
func resolveTCPAddrs(addr string, dualStack bool) ([]net.TCPAddr, error) {
host, portS, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
port, err := strconv.Atoi(portS)
if err != nil {
return nil, err
}
ips, err := net.LookupIP(host)
if err != nil {
return nil, err
}
n := len(ips)
addrs := make([]net.TCPAddr, 0, n)
for i := 0; i < n; i++ {
ip := ips[i]
if !dualStack && ip.To4() == nil {
continue
}
addrs = append(addrs, net.TCPAddr{
IP: ip,
Port: port,
})
}
return addrs, nil
}