-(dnsforward): fixed sigsegv when protection is disabled

Also, fixed all golint issues

✅ Closes: AdguardTeam#941

Author: ameshkov

.golangci.yml

@@ -13,6 +13,7 @@ run:
   skip-files:
     - ".*generated.*"
     - dnsfilter/rule_to_regexp.go
+    - ".*_test.go"
 
 
 # all available settings of specific linters

dhcpd/check_other_dhcp.go

@@ -17,6 +17,7 @@ import (
 
 // CheckIfOtherDHCPServersPresent sends a DHCP request to the specified network interface,
 // and waits for a response for a period defined by defaultDiscoverTime
+// nolint
 func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 	iface, err := net.InterfaceByName(ifaceName)
 	if err != nil {
@@ -95,16 +96,13 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 	if c != nil {
 		defer c.Close()
 	}
-	// spew.Dump(c, err)
-	// spew.Printf("net.ListenUDP returned %v, %v\n", c, err)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't listen on :68")
 	}
 
 	// send to 255.255.255.255:67
 	cm := ipv4.ControlMessage{}
 	_, err = c.WriteTo(packet, &cm, dstAddr)
-	// spew.Dump(n, err)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't send a packet to %s", dst)
 	}

dnsfilter/dnsfilter.go

@@ -148,7 +148,7 @@ const (
 	ReasonRewrite
 )
 
-func (i Reason) String() string {
+func (r Reason) String() string {
 	names := []string{
 		"NotFilteredNotFound",
 		"NotFilteredWhiteList",
@@ -163,10 +163,10 @@ func (i Reason) String() string {
 
 		"Rewrite",
 	}
-	if uint(i) >= uint(len(names)) {
+	if uint(r) >= uint(len(names)) {
 		return ""
 	}
-	return names[i]
+	return names[r]
 }
 
 type dnsFilterContext struct {

dnsforward/dnsforward.go

@@ -473,7 +473,6 @@ func (s *Server) handleDNSRequest(p *proxy.Proxy, d *proxy.DNSContext) error {
 		}
 
 		if res.Reason == dnsfilter.ReasonRewrite && len(res.CanonName) != 0 {
-
 			d.Req.Question[0] = originalQuestion
 			d.Res.Question[0] = originalQuestion
 
@@ -520,7 +519,7 @@ func (s *Server) filterDNSRequest(d *proxy.DNSContext) (*dnsfilter.Result, error
 	s.RUnlock()
 
 	if !protectionEnabled {
-		return nil, nil
+		return &dnsfilter.Result{}, nil
 	}
 
 	if host != origHost {

dnsforward/dnsforward_test.go

@@ -78,6 +78,39 @@ func TestServer(t *testing.T) {
 	}
 }
 
+func TestServerWithProtectionDisabled(t *testing.T) {
+	s := createTestServer(t)
+	s.conf.ProtectionEnabled = false
+	defer removeDataDir(t)
+	err := s.Start(nil)
+	if err != nil {
+		t.Fatalf("Failed to start server: %s", err)
+	}
+
+	// message over UDP
+	req := createGoogleATestMessage()
+	addr := s.dnsProxy.Addr(proxy.ProtoUDP)
+	client := dns.Client{Net: "udp"}
+	reply, _, err := client.Exchange(req, addr.String())
+	if err != nil {
+		t.Fatalf("Couldn't talk to server %s: %s", addr, err)
+	}
+	assertGoogleAResponse(t, reply)
+
+	// check query log and stats
+	log := s.GetQueryLog()
+	assert.Equal(t, 1, len(log), "Log size")
+	stats := s.GetStatsTop()
+	assert.Equal(t, 1, len(stats.Domains), "Top domains length")
+	assert.Equal(t, 0, len(stats.Blocked), "Top blocked length")
+	assert.Equal(t, 1, len(stats.Clients), "Top clients length")
+
+	err = s.Stop()
+	if err != nil {
+		t.Fatalf("DNS server failed to stop: %s", err)
+	}
+}
+
 func TestDotServer(t *testing.T) {
 	// Prepare the proxy server
 	_, certPem, keyPem := createServerTLSConfig(t)

home/home.go

@@ -61,6 +61,7 @@ func Main(version string, channel string) {
 
 // run initializes configuration and runs the AdGuard Home
 // run is a blocking method and it won't exit until the service is stopped!
+// nolint
 func run(args options) {
 	// config file path can be overridden by command-line arguments:
 	if args.configFilename != "" {