cloudflared-mirror/tunneldns/https_proxy.go

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package tunneldns
import (
"context"
"github.com/coredns/coredns/plugin"
"github.com/miekg/dns"
"github.com/pkg/errors"
)
// Upstream is a simplified interface for proxy destination
type Upstream interface {
Exchange(ctx context.Context, query *dns.Msg) (*dns.Msg, error)
}
// ProxyPlugin is a simplified DNS proxy using a generic upstream interface
type ProxyPlugin struct {
Upstreams []Upstream
Next plugin.Handler
}
// ServeDNS implements interface for CoreDNS plugin
func (p ProxyPlugin) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
var reply *dns.Msg
var backendErr error
for _, upstream := range p.Upstreams {
reply, backendErr = upstream.Exchange(ctx, r)
if backendErr == nil {
w.WriteMsg(reply)
return 0, nil
}
}
return dns.RcodeServerFailure, errors.Wrap(backendErr, "failed to contact any of the upstreams")
}
// Name implements interface for CoreDNS plugin
func (p ProxyPlugin) Name() string { return "proxy" }