* rDNS: refactor: move code to a separate file

home/dns.go

@@ -4,9 +4,7 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"strings"
 	"sync"
-	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/dnsfilter"
 	"github.com/AdguardTeam/AdGuardHome/dnsforward"
@@ -17,10 +15,6 @@ import (
 	"github.com/miekg/dns"
 )
 
-const (
-	rdnsTimeout = 3 * time.Second // max time to wait for rDNS response
-)
-
 type dnsContext struct {
 	rdnsChannel chan string // pass data from DNS request handling thread to rDNS thread
 	// contains IP addresses of clients to be resolved by rDNS
@@ -41,115 +35,13 @@ func initDNSServer(baseDir string) {
 
 	config.dnsServer = dnsforward.NewServer(baseDir)
 
-	bindhost := config.DNS.BindHost
+	initRDNS()
-	if config.DNS.BindHost == "0.0.0.0" {
-		bindhost = "127.0.0.1"
-	}
-	resolverAddress := fmt.Sprintf("%s:%d", bindhost, config.DNS.Port)
-	opts := upstream.Options{
-		Timeout: rdnsTimeout,
-	}
-	config.dnsctx.upstream, err = upstream.AddressToUpstream(resolverAddress, opts)
-	if err != nil {
-		log.Error("upstream.AddressToUpstream: %s", err)
-		return
-	}
-
-	config.dnsctx.rdnsIP = make(map[string]bool)
-	config.dnsctx.rdnsChannel = make(chan string, 256)
-	go asyncRDNSLoop()
 }
 
 func isRunning() bool {
 	return config.dnsServer != nil && config.dnsServer.IsRunning()
 }
 
-func beginAsyncRDNS(ip string) {
-	if config.clients.Exists(ip) {
-		return
-	}
-
-	// add IP to rdnsIP, if not exists
-	config.dnsctx.rdnsLock.Lock()
-	defer config.dnsctx.rdnsLock.Unlock()
-	_, ok := config.dnsctx.rdnsIP[ip]
-	if ok {
-		return
-	}
-	config.dnsctx.rdnsIP[ip] = true
-
-	log.Tracef("Adding %s for rDNS resolve", ip)
-	select {
-	case config.dnsctx.rdnsChannel <- ip:
-		//
-	default:
-		log.Tracef("rDNS queue is full")
-	}
-}
-
-// Use rDNS to get hostname by IP address
-func resolveRDNS(ip string) string {
-	log.Tracef("Resolving host for %s", ip)
-
-	req := dns.Msg{}
-	req.Id = dns.Id()
-	req.RecursionDesired = true
-	req.Question = []dns.Question{
-		{
-			Qtype:  dns.TypePTR,
-			Qclass: dns.ClassINET,
-		},
-	}
-	var err error
-	req.Question[0].Name, err = dns.ReverseAddr(ip)
-	if err != nil {
-		log.Debug("Error while calling dns.ReverseAddr(%s): %s", ip, err)
-		return ""
-	}
-
-	resp, err := config.dnsctx.upstream.Exchange(&req)
-	if err != nil {
-		log.Error("Error while making an rDNS lookup for %s: %s", ip, err)
-		return ""
-	}
-	if len(resp.Answer) != 1 {
-		log.Debug("No answer for rDNS lookup of %s", ip)
-		return ""
-	}
-	ptr, ok := resp.Answer[0].(*dns.PTR)
-	if !ok {
-		log.Error("not a PTR response for %s", ip)
-		return ""
-	}
-
-	log.Tracef("PTR response for %s: %s", ip, ptr.String())
-	if strings.HasSuffix(ptr.Ptr, ".") {
-		ptr.Ptr = ptr.Ptr[:len(ptr.Ptr)-1]
-	}
-
-	return ptr.Ptr
-}
-
-// Wait for a signal and then synchronously resolve hostname by IP address
-// Add the hostname:IP pair to "Clients" array
-func asyncRDNSLoop() {
-	for {
-		var ip string
-		ip = <-config.dnsctx.rdnsChannel
-
-		host := resolveRDNS(ip)
-		if len(host) == 0 {
-			continue
-		}
-
-		config.dnsctx.rdnsLock.Lock()
-		delete(config.dnsctx.rdnsIP, ip)
-		config.dnsctx.rdnsLock.Unlock()
-
-		_, _ = config.clients.AddHost(ip, host, ClientSourceRDNS)
-	}
-}
-
 func onDNSRequest(d *proxy.DNSContext) {
 	qType := d.Req.Question[0].Qtype
 	if qType != dns.TypeA && qType != dns.TypeAAAA {

home/rdns.go

@@ -0,0 +1,125 @@
+package home
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/AdguardTeam/dnsproxy/upstream"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/miekg/dns"
+)
+
+const (
+	rdnsTimeout = 3 * time.Second // max time to wait for rDNS response
+)
+
+func initRDNS() {
+	var err error
+
+	bindhost := config.DNS.BindHost
+	if config.DNS.BindHost == "0.0.0.0" {
+		bindhost = "127.0.0.1"
+	}
+	resolverAddress := fmt.Sprintf("%s:%d", bindhost, config.DNS.Port)
+
+	opts := upstream.Options{
+		Timeout: rdnsTimeout,
+	}
+	config.dnsctx.upstream, err = upstream.AddressToUpstream(resolverAddress, opts)
+	if err != nil {
+		log.Error("upstream.AddressToUpstream: %s", err)
+		return
+	}
+
+	config.dnsctx.rdnsIP = make(map[string]bool)
+	config.dnsctx.rdnsChannel = make(chan string, 256)
+	go asyncRDNSLoop()
+}
+
+// Add IP address to the rDNS queue
+func beginAsyncRDNS(ip string) {
+	if config.clients.Exists(ip) {
+		return
+	}
+
+	// add IP to rdnsIP, if not exists
+	config.dnsctx.rdnsLock.Lock()
+	defer config.dnsctx.rdnsLock.Unlock()
+	_, ok := config.dnsctx.rdnsIP[ip]
+	if ok {
+		return
+	}
+	config.dnsctx.rdnsIP[ip] = true
+
+	log.Tracef("Adding %s for rDNS resolve", ip)
+	select {
+	case config.dnsctx.rdnsChannel <- ip:
+		//
+	default:
+		log.Tracef("rDNS queue is full")
+	}
+}
+
+// Use rDNS to get hostname by IP address
+func resolveRDNS(ip string) string {
+	log.Tracef("Resolving host for %s", ip)
+
+	req := dns.Msg{}
+	req.Id = dns.Id()
+	req.RecursionDesired = true
+	req.Question = []dns.Question{
+		{
+			Qtype:  dns.TypePTR,
+			Qclass: dns.ClassINET,
+		},
+	}
+	var err error
+	req.Question[0].Name, err = dns.ReverseAddr(ip)
+	if err != nil {
+		log.Debug("Error while calling dns.ReverseAddr(%s): %s", ip, err)
+		return ""
+	}
+
+	resp, err := config.dnsctx.upstream.Exchange(&req)
+	if err != nil {
+		log.Error("Error while making an rDNS lookup for %s: %s", ip, err)
+		return ""
+	}
+	if len(resp.Answer) != 1 {
+		log.Debug("No answer for rDNS lookup of %s", ip)
+		return ""
+	}
+	ptr, ok := resp.Answer[0].(*dns.PTR)
+	if !ok {
+		log.Error("not a PTR response for %s", ip)
+		return ""
+	}
+
+	log.Tracef("PTR response for %s: %s", ip, ptr.String())
+	if strings.HasSuffix(ptr.Ptr, ".") {
+		ptr.Ptr = ptr.Ptr[:len(ptr.Ptr)-1]
+	}
+
+	return ptr.Ptr
+}
+
+// Wait for a signal and then synchronously resolve hostname by IP address
+// Add the hostname:IP pair to "Clients" array
+func asyncRDNSLoop() {
+	for {
+		var ip string
+		ip = <-config.dnsctx.rdnsChannel
+
+		host := resolveRDNS(ip)
+		if len(host) == 0 {
+			continue
+		}
+
+		config.dnsctx.rdnsLock.Lock()
+		delete(config.dnsctx.rdnsIP, ip)
+		config.dnsctx.rdnsLock.Unlock()
+
+		_, _ = config.clients.AddHost(ip, host, ClientSourceRDNS)
+	}
+}