dnsforward: imp code, docs

AdguardTeam · Sep 2, 2022 · b874088 · b874088
1 parent a1b95fd
commit b874088
Showing 1 changed file with 17 additions and 11 deletions.
diff --git a/internal/dnsforward/dns.go b/internal/dnsforward/dns.go
@@ -125,8 +125,10 @@ func (s *Server) handleDNSRequest(_ *proxy.Proxy, pctx *proxy.DNSContext) error
 	}
 
 	if pctx.Res != nil {
-		pctx.Res.Compress = true // some devices require DNS message compression
+		// Some devices require DNS message compression.
+		pctx.Res.Compress = true
 	}
+
 	return nil
 }
 
@@ -151,25 +153,29 @@ func (s *Server) processRecursion(dctx *dnsContext) (rc resultCode) {
 // TODO(e.burkov):  Decompose into less general processors.
 func (s *Server) processInitial(dctx *dnsContext) (rc resultCode) {
 	pctx := dctx.proxyCtx
-	if s.conf.AAAADisabled && pctx.Req.Question[0].Qtype == dns.TypeAAAA {
+	q := pctx.Req.Question[0]
+	qt := q.Qtype
+	if s.conf.AAAADisabled && qt == dns.TypeAAAA {
 		_ = proxy.CheckDisabledAAAARequest(pctx, true)
+
 		return resultCodeFinish
 	}
 
 	if s.conf.OnDNSRequest != nil {
 		s.conf.OnDNSRequest(pctx)
 	}
 
-	// disable Mozilla DoH
-	// https://support.mozilla.org/en-US/kb/canary-domain-use-application-dnsnet
-	if (pctx.Req.Question[0].Qtype == dns.TypeA || pctx.Req.Question[0].Qtype == dns.TypeAAAA) &&
-		pctx.Req.Question[0].Name == "use-application-dns.net." {
+	// Disable Mozilla DoH.
+	//
+	// See https://support.mozilla.org/en-US/kb/canary-domain-use-application-dnsnet.
+	if (qt == dns.TypeA || qt == dns.TypeAAAA) && q.Name == "use-application-dns.net." {
 		pctx.Res = s.genNXDomain(pctx.Req)
+
 		return resultCodeFinish
 	}
 
-	// Get the client's ID if any.  It should be performed before getting
-	// client-specific filtering settings.
+	// Get the ClientID, if any, before getting client-specific filtering
+	// settings.
 	var key [8]byte
 	binary.BigEndian.PutUint64(key[:], pctx.RequestID)
 	dctx.clientID = string(s.clientIDCache.Get(key[:]))
@@ -251,15 +257,15 @@ func (s *Server) onDHCPLeaseChanged(flags int) {
 // See https://www.ietf.org/archive/id/draft-ietf-add-ddr-06.html.
 func (s *Server) processDDRQuery(dctx *dnsContext) (rc resultCode) {
 	pctx := dctx.proxyCtx
-	question := pctx.Req.Question[0]
+	q := pctx.Req.Question[0]
 
 	if !s.conf.HandleDDR {
 		return resultCodeSuccess
 	}
 
-	if question.Name == ddrHostFQDN {
+	if q.Name == ddrHostFQDN {
 		if s.dnsProxy.TLSListenAddr == nil && s.conf.HTTPSListenAddrs == nil &&
-			s.dnsProxy.QUICListenAddr == nil || question.Qtype != dns.TypeSVCB {
+			s.dnsProxy.QUICListenAddr == nil || q.Qtype != dns.TypeSVCB {
 			pctx.Res = s.makeResponse(pctx.Req)
 
 			return resultCodeFinish