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package forward
import (
"crypto/tls"
"sync"
"time"
"github.com/miekg/dns"
)
// Proxy defines an upstream host.
type Proxy struct {
host *host
transport *transport
// copied from Forward.
hcInterval time.Duration
forceTCP bool
stop chan bool
sync.RWMutex
}
// NewProxy returns a new proxy.
func NewProxy(addr string) *Proxy {
host := newHost(addr)
p := &Proxy{
host: host,
hcInterval: hcDuration,
stop: make(chan bool),
transport: newTransport(host),
}
return p
}
// SetTLSConfig sets the TLS config in the lower p.host.
func (p *Proxy) SetTLSConfig(cfg *tls.Config) { p.host.tlsConfig = cfg }
// SetExpire sets the expire duration in the lower p.host.
func (p *Proxy) SetExpire(expire time.Duration) { p.host.expire = expire }
func (p *Proxy) close() { p.stop <- true }
// Dial connects to the host in p with the configured transport.
func (p *Proxy) Dial(proto string) (*dns.Conn, error) { return p.transport.Dial(proto) }
// Yield returns the connection to the pool.
func (p *Proxy) Yield(c *dns.Conn) { p.transport.Yield(c) }
// Down returns if this proxy is up or down.
func (p *Proxy) Down(maxfails uint32) bool { return p.host.down(maxfails) }
func (p *Proxy) healthCheck() {
// stop channel
p.host.SetClient()
p.host.Check()
tick := time.NewTicker(p.hcInterval)
for {
select {
case <-tick.C:
p.host.Check()
case <-p.stop:
return
}
}
}
const (
dialTimeout = 4 * time.Second
timeout = 2 * time.Second
hcDuration = 500 * time.Millisecond
)
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