Pull request: 4927-ddr-ip-san

Merge in DNS/adguard-home from 4927-ddr-ip-san to master

Updates #4927.

Squashed commit of the following:

commit 92e7498a7a9101648c4cfdf719adf4eb135fc903
Merge: f4770abf fa0fd90d
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Nov 2 14:29:08 2022 +0300

    Merge branch 'master' into 4927-ddr-ip-san

commit f4770abf98ea2c0db2f0c2ddb9509a29a06c9509
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Nov 2 13:50:40 2022 +0300

    dnsforward: imp logs

commit 8d71371365070e221e104ae20acc8312e840eff9
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 1 20:57:43 2022 +0300

    all: imp code, docs

commit 9793820f2c581e0ffcb28a59677be5c8df0c43f3
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 1 19:37:39 2022 +0300

    all: remember the cert props

internal/aghtls/aghtls.go

@@ -3,7 +3,9 @@ package aghtls
 
 import (
 	"crypto/tls"
+	"crypto/x509"
 	"fmt"
+	"net/netip"
 
 	"github.com/AdguardTeam/golibs/log"
 )
@@ -69,3 +71,19 @@ func SaferCipherSuites() (safe []uint16) {
 
 	return safe
 }
+
+// CertificateHasIP returns true if cert has at least a single IP address among
+// its subjectAltNames.
+func CertificateHasIP(cert *x509.Certificate) (ok bool) {
+	if len(cert.IPAddresses) > 0 {
+		return true
+	}
+
+	for _, name := range cert.DNSNames {
+		if _, err := netip.ParseAddr(name); err == nil {
+			return true
+		}
+	}
+
+	return false
+}