Fix miscellaneous style issues (#2421)

Found by running: golangci-lint run --enable-all

I have only addressed the reported issues that seemed relevant to me.

dnscrypt-proxy/common.go

@@ -46,11 +46,6 @@ const (
 	InheritedDescriptorsBase = uintptr(50)
 )
 
-const (
-	IPv4Arpa = "in-addr.arpa"
-	IPv6Arpa = "ip6.arpa"
-)
-
 func PrefixWithSize(packet []byte) ([]byte, error) {
 	packetLen := len(packet)
 	if packetLen > 0xffff {

dnscrypt-proxy/config.go

@@ -906,7 +906,7 @@ func (config *Config) loadSource(proxy *Proxy, cfgSourceName string, cfgSource *
 		cfgSource.Prefix,
 	)
 	if err != nil {
-		if len(source.bin) <= 0 {
+		if len(source.bin) == 0 {
 			dlog.Criticalf("Unable to retrieve source [%s]: [%s]", cfgSourceName, err)
 			return err
 		}

dnscrypt-proxy/dnscrypt_certs.go

@@ -35,7 +35,7 @@ func FetchCurrentDNSCryptCert(
 		return CertInfo{}, 0, false, errors.New("Invalid public key length")
 	}
 	if !strings.HasSuffix(providerName, ".") {
-		providerName = providerName + "."
+		providerName += "."
 	}
 	if serverName == nil {
 		serverName = &providerName

dnscrypt-proxy/main.go

@@ -35,7 +35,7 @@ func main() {
 	if _, err := crypto_rand.Read(seed); err != nil {
 		dlog.Fatal(err)
 	}
-	rand.Seed(int64(binary.LittleEndian.Uint64(seed[:])))
+	rand.Seed(int64(binary.LittleEndian.Uint64(seed)))
 
 	pwd, err := os.Getwd()
 	if err != nil {

dnscrypt-proxy/netprobe_others.go

@@ -11,7 +11,7 @@ import (
 )
 
 func NetProbe(proxy *Proxy, address string, timeout int) error {
-	if len(address) <= 0 || timeout == 0 {
+	if len(address) == 0 || timeout == 0 {
 		return nil
 	}
 	if captivePortalHandler, err := ColdStart(proxy); err == nil {

dnscrypt-proxy/oblivious_doh.go

@@ -181,7 +181,7 @@ func (q ODoHQuery) decryptResponse(response []byte) ([]byte, error) {
 	responseLength := binary.BigEndian.Uint16(responsePlaintext[0:2])
 	valid := 1
 	for i := 4 + int(responseLength); i < len(responsePlaintext); i++ {
-		valid = valid & subtle.ConstantTimeByteEq(response[i], 0x00)
+		valid &= subtle.ConstantTimeByteEq(response[i], 0x00)
 	}
 	if valid != 1 {
 		return nil, fmt.Errorf("Malformed response")

dnscrypt-proxy/plugin_allow_ip.go

@@ -36,7 +36,7 @@ func (plugin *PluginAllowedIP) Init(proxy *Proxy) error {
 	}
 	plugin.allowedPrefixes = iradix.New()
 	plugin.allowedIPs = make(map[string]interface{})
-	for lineNo, line := range strings.Split(string(bin), "\n") {
+	for lineNo, line := range strings.Split(bin, "\n") {
 		line = TrimAndStripInlineComments(line)
 		if len(line) == 0 {
 			continue

dnscrypt-proxy/plugin_cloak.go

@@ -47,7 +47,7 @@ func (plugin *PluginCloak) Init(proxy *Proxy) error {
 	plugin.createPTR = proxy.cloakedPTR
 	plugin.patternMatcher = NewPatternMatcher()
 	cloakedNames := make(map[string]*CloakedName)
-	for lineNo, line := range strings.Split(string(bin), "\n") {
+	for lineNo, line := range strings.Split(bin, "\n") {
 		line = TrimAndStripInlineComments(line)
 		if len(line) == 0 {
 			continue
@@ -73,9 +73,9 @@ func (plugin *PluginCloak) Init(proxy *Proxy) error {
 		ip := net.ParseIP(target)
 		if ip != nil {
 			if ipv4 := ip.To4(); ipv4 != nil {
-				cloakedName.ipv4 = append((*cloakedName).ipv4, ipv4)
+				cloakedName.ipv4 = append(cloakedName.ipv4, ipv4)
 			} else if ipv6 := ip.To16(); ipv6 != nil {
-				cloakedName.ipv6 = append((*cloakedName).ipv6, ipv6)
+				cloakedName.ipv6 = append(cloakedName.ipv6, ipv6)
 			} else {
 				dlog.Errorf("Invalid IP address in cloaking rule at line %d", 1+lineNo)
 				continue

dnscrypt-proxy/plugins.go

@@ -189,11 +189,11 @@ func parseBlockedQueryResponse(blockedResponse string, pluginsGlobals *PluginsGl
 
 	if strings.HasPrefix(blockedResponse, "a:") {
 		blockedIPStrings := strings.Split(blockedResponse, ",")
-		(*pluginsGlobals).respondWithIPv4 = net.ParseIP(strings.TrimPrefix(blockedIPStrings[0], "a:"))
+		pluginsGlobals.respondWithIPv4 = net.ParseIP(strings.TrimPrefix(blockedIPStrings[0], "a:"))
 
-		if (*pluginsGlobals).respondWithIPv4 == nil {
+		if pluginsGlobals.respondWithIPv4 == nil {
 			dlog.Notice("Error parsing IPv4 response given in blocked_query_response option, defaulting to `hinfo`")
-			(*pluginsGlobals).refusedCodeInResponses = false
+			pluginsGlobals.refusedCodeInResponses = false
 			return
 		}
 
@@ -203,9 +203,9 @@ func parseBlockedQueryResponse(blockedResponse string, pluginsGlobals *PluginsGl
 				if strings.HasPrefix(ipv6Response, "[") {
 					ipv6Response = strings.Trim(ipv6Response, "[]")
 				}
-				(*pluginsGlobals).respondWithIPv6 = net.ParseIP(ipv6Response)
+				pluginsGlobals.respondWithIPv6 = net.ParseIP(ipv6Response)
 
-				if (*pluginsGlobals).respondWithIPv6 == nil {
+				if pluginsGlobals.respondWithIPv6 == nil {
 					dlog.Notice(
 						"Error parsing IPv6 response given in blocked_query_response option, defaulting to IPv4",
 					)
@@ -215,18 +215,18 @@ func parseBlockedQueryResponse(blockedResponse string, pluginsGlobals *PluginsGl
 			}
 		}
 
-		if (*pluginsGlobals).respondWithIPv6 == nil {
-			(*pluginsGlobals).respondWithIPv6 = (*pluginsGlobals).respondWithIPv4
+		if pluginsGlobals.respondWithIPv6 == nil {
+			pluginsGlobals.respondWithIPv6 = pluginsGlobals.respondWithIPv4
 		}
 	} else {
 		switch blockedResponse {
 		case "refused":
-			(*pluginsGlobals).refusedCodeInResponses = true
+			pluginsGlobals.refusedCodeInResponses = true
 		case "hinfo":
-			(*pluginsGlobals).refusedCodeInResponses = false
+			pluginsGlobals.refusedCodeInResponses = false
 		default:
 			dlog.Noticef("Invalid blocked_query_response option [%s], defaulting to `hinfo`", blockedResponse)
-			(*pluginsGlobals).refusedCodeInResponses = false
+			pluginsGlobals.refusedCodeInResponses = false
 		}
 	}
 }

dnscrypt-proxy/proxy.go

@@ -127,7 +127,7 @@ func (proxy *Proxy) addDNSListener(listenAddrStr string) {
 	}
 
 	// if 'userName' is not set, continue as before
-	if len(proxy.userName) <= 0 {
+	if len(proxy.userName) == 0 {
 		if err := proxy.udpListenerFromAddr(listenUDPAddr); err != nil {
 			dlog.Fatal(err)
 		}
@@ -191,7 +191,7 @@ func (proxy *Proxy) addLocalDoHListener(listenAddrStr string) {
 	}
 
 	// if 'userName' is not set, continue as before
-	if len(proxy.userName) <= 0 {
+	if len(proxy.userName) == 0 {
 		if err := proxy.localDoHListenerFromAddr(listenTCPAddr); err != nil {
 			dlog.Fatal(err)
 		}
@@ -619,7 +619,7 @@ func (proxy *Proxy) processIncomingQuery(
 	start time.Time,
 	onlyCached bool,
 ) []byte {
-	var response []byte = nil
+	var response []byte
 	if len(query) < MinDNSPacketSize {
 		return response
 	}

dnscrypt-proxy/serversInfo.go

@@ -312,7 +312,7 @@ func (serversInfo *ServersInfo) getOne() *ServerInfo {
 		serversInfo.estimatorUpdate(candidate)
 	}
 	serverInfo := serversInfo.inner[candidate]
-	dlog.Debugf("Using candidate [%s] RTT: %d", (*serverInfo).Name, int((*serverInfo).rtt.Value()))
+	dlog.Debugf("Using candidate [%s] RTT: %d", serverInfo.Name, int(serverInfo.rtt.Value()))
 	serversInfo.Unlock()
 
 	return serverInfo
@@ -534,7 +534,7 @@ func route(proxy *Proxy, name string, serverProto stamps.StampProtoType) (*Relay
 
 func fetchDNSCryptServerInfo(proxy *Proxy, name string, stamp stamps.ServerStamp, isNew bool) (ServerInfo, error) {
 	if len(stamp.ServerPk) != ed25519.PublicKeySize {
-		serverPk, err := hex.DecodeString(strings.Replace(string(stamp.ServerPk), ":", "", -1))
+		serverPk, err := hex.DecodeString(strings.ReplaceAll(string(stamp.ServerPk), ":", ""))
 		if err != nil || len(serverPk) != ed25519.PublicKeySize {
 			dlog.Fatalf("Unsupported public key for [%s]: [%s]", name, stamp.ServerPk)
 		}