blob: 02d3512cb88ea8526c7a822b24006c1a06d66297 (
plain) (
blame)
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
|
package forward
import (
"crypto/tls"
"sync/atomic"
"time"
"github.com/coredns/coredns/plugin/pkg/up"
"github.com/miekg/dns"
)
// Proxy defines an upstream host.
type Proxy struct {
addr string
client *dns.Client
// Connection caching
expire time.Duration
transport *transport
// health checking
probe *up.Probe
fails uint32
}
// NewProxy returns a new proxy.
func NewProxy(addr string, tlsConfig *tls.Config) *Proxy {
p := &Proxy{
addr: addr,
fails: 0,
probe: up.New(),
transport: newTransport(addr, tlsConfig),
}
p.client = dnsClient(tlsConfig)
return p
}
// dnsClient returns a client used for health checking.
func dnsClient(tlsConfig *tls.Config) *dns.Client {
c := new(dns.Client)
c.Net = "udp"
// TODO(miek): this should be half of hcDuration?
c.ReadTimeout = 1 * time.Second
c.WriteTimeout = 1 * time.Second
if tlsConfig != nil {
c.Net = "tcp-tls"
c.TLSConfig = tlsConfig
}
return c
}
// SetTLSConfig sets the TLS config in the lower p.transport.
func (p *Proxy) SetTLSConfig(cfg *tls.Config) { p.transport.SetTLSConfig(cfg) }
// SetExpire sets the expire duration in the lower p.transport.
func (p *Proxy) SetExpire(expire time.Duration) { p.transport.SetExpire(expire) }
// Dial connects to the host in p with the configured transport.
func (p *Proxy) Dial(proto string) (*dns.Conn, bool, error) { return p.transport.Dial(proto) }
// Yield returns the connection to the pool.
func (p *Proxy) Yield(c *dns.Conn) { p.transport.Yield(c) }
// Healthcheck kicks of a round of health checks for this proxy.
func (p *Proxy) Healthcheck() { p.probe.Do(p.Check) }
// Down returns true if this proxy is down, i.e. has *more* fails than maxfails.
func (p *Proxy) Down(maxfails uint32) bool {
if maxfails == 0 {
return false
}
fails := atomic.LoadUint32(&p.fails)
return fails > maxfails
}
// close stops the health checking goroutine.
func (p *Proxy) close() {
p.probe.Stop()
p.transport.Stop()
}
// start starts the proxy's healthchecking.
func (p *Proxy) start(duration time.Duration) { p.probe.Start(duration) }
const (
dialTimeout = 4 * time.Second
timeout = 2 * time.Second
hcDuration = 500 * time.Millisecond
)
|
