Add DNS over TLS ipv6 upstream servers, see #88

internal/settings/dns.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/qdm12/private-internet-access-docker/internal/constants"
 	"github.com/qdm12/private-internet-access-docker/internal/models"
 	"github.com/qdm12/private-internet-access-docker/internal/params"
 )
@@ -112,5 +113,21 @@ func GetDNSSettings(params params.ParamsReader) (settings DNS, err error) {
 	if err != nil {
 		return settings, err
 	}
+
+	// Consistency check
+	IPv6Support := false
+	for _, provider := range settings.Providers {
+		providerData, ok := constants.DNSProviderMapping()[provider]
+		if !ok {
+			return settings, fmt.Errorf("DNS provider %q does not have associated data", provider)
+		} else if !providerData.SupportsTLS {
+			return settings, fmt.Errorf("DNS provider %q does not support DNS over TLS", provider)
+		} else if providerData.SupportsIPv6 {
+			IPv6Support = true
+		}
+	}
+	if settings.IPv6 && !IPv6Support {
+		return settings, fmt.Errorf("None of the DNS over TLS provider(s) set support IPv6")
+	}
 	return settings, nil
 }