pancheri/handler.go

package pancheri

import (
	"github.com/miekg/dns"
	"github.com/sirupsen/logrus"
)

type Handler struct {
	C *Config
	R *Resolver
	A *Authority
}

func (h *Handler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {

	// figure out how we should resolve this
	msg := new(dns.Msg)
	msg.SetReply(r)
	msg.Authoritative = true

	if len(r.Question) != 1 {
		msg.Rcode = dns.RcodeFormatError
		err := w.WriteMsg(msg)
		if err != nil {
			logrus.Errorf("error responding: %s", err)
			return
		}
		return
	}

	question := r.Question[0]

	// okay, do we have upstream resolution enabled?
	if h.C.Resolver.Enable {
		// alright, resolve it with the resolver
		answers, rcode, err := h.R.Resolve(question.Name, question.Qtype)
		if err != nil {
			logrus.Errorf("error resolving: %s", err)
			return
		}
		msg.Rcode = rcode
		msg.Answer = append(msg.Answer, answers...)

		err = w.WriteMsg(msg)
		if err != nil {
			logrus.Errorf("error responding: %s", err)
			return
		}
	} else {
		// alright, send an nxdomain
		if r.RecursionDesired {
			msg.RecursionAvailable = true
		}
		msg.Rcode = dns.RcodeNameError

		err := w.WriteMsg(msg)
		if err != nil {
			logrus.Errorf("error responding: %s", err)
			return
		}
	}
}