Pull request: home: fix tls config comparison

Closes #3411.

Squashed commit of the following:

commit 42deaa1ca804429a5c523641997b4e8d453952e6
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Aug 3 19:47:32 2021 +0300

    home: imp code

commit a69f6469e5e76e17c83537f7a763f047201fd15a
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Aug 3 18:54:59 2021 +0300

    home: fix tls config comparison

internal/home/tls.go

@@ -19,6 +19,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
 	"github.com/AdguardTeam/golibs/errors"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/google/go-cmp/cmp"
@@ -30,9 +31,9 @@ var tlsWebHandlersRegistered = false
 // TLSMod - TLS module object
 type TLSMod struct {
 	certLastMod time.Time // last modification time of the certificate file
-	conf        tlsConfigSettings
-	confLock    sync.Mutex
 	status      tlsConfigStatus
+	confLock    sync.Mutex
+	conf        tlsConfigSettings
 }
 
 // Create TLS module
@@ -209,8 +210,8 @@ type tlsConfigStatus struct {
 
 // field ordering is important -- yaml fields will mirror ordering from here
 type tlsConfig struct {
-	tlsConfigSettings `json:",inline"`
 	tlsConfigStatus   `json:",inline"`
+	tlsConfigSettings `json:",inline"`
 }
 
 func (t *TLSMod) handleTLSStatus(w http.ResponseWriter, _ *http.Request) {
@@ -247,6 +248,41 @@ func (t *TLSMod) handleTLSValidate(w http.ResponseWriter, r *http.Request) {
 	marshalTLS(w, data)
 }
 
+func (t *TLSMod) setConfig(newConf tlsConfigSettings, status tlsConfigStatus) (restartHTTPS bool) {
+	t.confLock.Lock()
+	defer t.confLock.Unlock()
+
+	// Reset the DNSCrypt data before comparing, since we currently do not
+	// accept these from the frontend.
+	//
+	// TODO(a.garipov): Define a custom comparer for dnsforward.TLSConfig.
+	newConf.DNSCryptConfigFile = t.conf.DNSCryptConfigFile
+	newConf.PortDNSCrypt = t.conf.PortDNSCrypt
+	if !cmp.Equal(t.conf, newConf, cmp.AllowUnexported(dnsforward.TLSConfig{})) {
+		log.Info("tls config has changed, restarting https server")
+		restartHTTPS = true
+	} else {
+		log.Info("tls config has not changed")
+	}
+
+	// Note: don't do just `t.conf = data` because we must preserve all other members of t.conf
+	t.conf.Enabled = newConf.Enabled
+	t.conf.ServerName = newConf.ServerName
+	t.conf.ForceHTTPS = newConf.ForceHTTPS
+	t.conf.PortHTTPS = newConf.PortHTTPS
+	t.conf.PortDNSOverTLS = newConf.PortDNSOverTLS
+	t.conf.PortDNSOverQUIC = newConf.PortDNSOverQUIC
+	t.conf.CertificateChain = newConf.CertificateChain
+	t.conf.CertificatePath = newConf.CertificatePath
+	t.conf.CertificateChainData = newConf.CertificateChainData
+	t.conf.PrivateKey = newConf.PrivateKey
+	t.conf.PrivateKeyPath = newConf.PrivateKeyPath
+	t.conf.PrivateKeyData = newConf.PrivateKeyData
+	t.status = status
+
+	return restartHTTPS
+}
+
 func (t *TLSMod) handleTLSConfigure(w http.ResponseWriter, r *http.Request) {
 	data, err := unmarshalTLS(r)
 	if err != nil {
@@ -266,42 +302,28 @@ func (t *TLSMod) handleTLSConfigure(w http.ResponseWriter, r *http.Request) {
 			tlsConfigStatus:   t.status,
 		}
 		marshalTLS(w, data2)
+
 		return
 	}
-	status = validateCertificates(string(data.CertificateChainData), string(data.PrivateKeyData), data.ServerName)
-	restartHTTPS := false
 
-	t.confLock.Lock()
+	status = validateCertificates(string(data.CertificateChainData), string(data.PrivateKeyData), data.ServerName)
-	if !cmp.Equal(t.conf, data) {
+
-		log.Printf("tls config settings have changed, will restart HTTPS server")
+	restartHTTPS := t.setConfig(data, status)
-		restartHTTPS = true
-	}
-	// Note: don't do just `t.conf = data` because we must preserve all other members of t.conf
-	t.conf.Enabled = data.Enabled
-	t.conf.ServerName = data.ServerName
-	t.conf.ForceHTTPS = data.ForceHTTPS
-	t.conf.PortHTTPS = data.PortHTTPS
-	t.conf.PortDNSOverTLS = data.PortDNSOverTLS
-	t.conf.PortDNSOverQUIC = data.PortDNSOverQUIC
-	t.conf.CertificateChain = data.CertificateChain
-	t.conf.CertificatePath = data.CertificatePath
-	t.conf.CertificateChainData = data.CertificateChainData
-	t.conf.PrivateKey = data.PrivateKey
-	t.conf.PrivateKeyPath = data.PrivateKeyPath
-	t.conf.PrivateKeyData = data.PrivateKeyData
-	t.status = status
-	t.confLock.Unlock()
 	t.setCertFileTime()
 	onConfigModified()
+
 	err = reconfigureDNSServer()
 	if err != nil {
 		httpError(w, http.StatusInternalServerError, "%s", err)
+
 		return
 	}
+
 	data2 := tlsConfig{
 		tlsConfigSettings: data,
 		tlsConfigStatus:   t.status,
 	}
+
 	marshalTLS(w, data2)
 	if f, ok := w.(http.Flusher); ok {
 		f.Flush()