7ac507d9ff
- connManager() goroutine will stop when Proxy is about to be garbage collected. This means that no queries are in progress, and no queries are going to come
111 lines
2.6 KiB
Go
111 lines
2.6 KiB
Go
package forward
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import (
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"crypto/tls"
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"runtime"
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"sync/atomic"
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"time"
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"github.com/coredns/coredns/plugin/pkg/up"
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"github.com/miekg/dns"
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)
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// Proxy defines an upstream host.
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type Proxy struct {
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addr string
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client *dns.Client
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// Connection caching
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expire time.Duration
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transport *transport
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// health checking
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probe *up.Probe
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fails uint32
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avgRtt int64
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}
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// NewProxy returns a new proxy.
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func NewProxy(addr string, tlsConfig *tls.Config) *Proxy {
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p := &Proxy{
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addr: addr,
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fails: 0,
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probe: up.New(),
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transport: newTransport(addr, tlsConfig),
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avgRtt: int64(timeout / 2),
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}
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p.client = dnsClient(tlsConfig)
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runtime.SetFinalizer(p, (*Proxy).finalizer)
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return p
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}
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// Addr returns the address to forward to.
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func (p *Proxy) Addr() (addr string) { return p.addr }
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// dnsClient returns a client used for health checking.
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func dnsClient(tlsConfig *tls.Config) *dns.Client {
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c := new(dns.Client)
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c.Net = "udp"
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// TODO(miek): this should be half of hcDuration?
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c.ReadTimeout = 1 * time.Second
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c.WriteTimeout = 1 * time.Second
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if tlsConfig != nil {
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c.Net = "tcp-tls"
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c.TLSConfig = tlsConfig
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}
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return c
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}
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// SetTLSConfig sets the TLS config in the lower p.transport and in the healthchecking client.
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func (p *Proxy) SetTLSConfig(cfg *tls.Config) {
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p.transport.SetTLSConfig(cfg)
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p.client = dnsClient(cfg)
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}
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// IsTLS returns true if proxy uses tls.
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func (p *Proxy) IsTLS() bool { return p.transport.tlsConfig != nil }
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// SetExpire sets the expire duration in the lower p.transport.
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func (p *Proxy) SetExpire(expire time.Duration) { p.transport.SetExpire(expire) }
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// Dial connects to the host in p with the configured transport.
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func (p *Proxy) Dial(proto string) (*dns.Conn, bool, error) { return p.transport.Dial(proto) }
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// Yield returns the connection to the pool.
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func (p *Proxy) Yield(c *dns.Conn) { p.transport.Yield(c) }
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// Healthcheck kicks of a round of health checks for this proxy.
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func (p *Proxy) Healthcheck() { p.probe.Do(p.Check) }
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// Down returns true if this proxy is down, i.e. has *more* fails than maxfails.
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func (p *Proxy) Down(maxfails uint32) bool {
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if maxfails == 0 {
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return false
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}
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fails := atomic.LoadUint32(&p.fails)
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return fails > maxfails
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}
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// close stops the health checking goroutine.
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func (p *Proxy) close() {
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p.probe.Stop()
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}
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func (p *Proxy) finalizer() {
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p.transport.Stop()
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}
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// start starts the proxy's healthchecking.
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func (p *Proxy) start(duration time.Duration) { p.probe.Start(duration) }
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const (
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dialTimeout = 4 * time.Second
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timeout = 2 * time.Second
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maxTimeout = 2 * time.Second
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minTimeout = 10 * time.Millisecond
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hcDuration = 500 * time.Millisecond
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)
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