Use DoT as fallback (#1597)

* Use DoT as fallback / add cache

* Stage

* merge

* fix lint

* Fallback server

* use fallback

* add nxdomain

* Address comments

rootfs/etc/services.d/supervisor/run

@@ -2,4 +2,6 @@
 # ==============================================================================
 # Start Service service
 # ==============================================================================
+export LD_PRELOAD="/usr/local/lib/libjemalloc.so.2"
+
 exec python3 -m supervisor

supervisor/const.py

@@ -34,7 +34,6 @@ DOCKER_NETWORK = "hassio"
 DOCKER_NETWORK_MASK = ip_network("172.30.32.0/23")
 DOCKER_NETWORK_RANGE = ip_network("172.30.33.0/24")
 
-DNS_SERVERS = ["dns://1.1.1.1", "dns://9.9.9.9"]
 DNS_SUFFIX = "local.hass.io"
 
 LABEL_VERSION = "io.hass.version"

supervisor/data/coredns.tmpl

@@ -1,15 +1,31 @@
 .:53 {
     log
     errors
+    loop
     hosts /config/hosts {
         fallthrough
     }
     template ANY AAAA local.hass.io hassio {
         rcode NOERROR
     }
-    forward . $servers {
+    forward . {{ locals | join(" ") }} dns://127.0.0.1:5353 {
         except local.hass.io
         policy sequential
+        health_check 5s
+    }
+    fallback REFUSED . dns://127.0.0.1:5353
+    fallback SERVFAIL . dns://127.0.0.1:5353
+    fallback NXDOMAIN . dns://127.0.0.1:5353
+    cache 10
+}
+
+.:5353 {
+    log
+    errors
+    forward . tls://1.1.1.1 tls://1.0.0.1 {
+        tls_servername cloudflare-dns.com
+        except local.hass.io
         health_check 10s
     }
+    cache 30
 }

supervisor/dns.py

@@ -4,13 +4,13 @@ from contextlib import suppress
 from ipaddress import IPv4Address
 import logging
 from pathlib import Path
-from string import Template
 from typing import Awaitable, List, Optional
 
 import attr
+import jinja2
 import voluptuous as vol
 
-from .const import ATTR_SERVERS, ATTR_VERSION, DNS_SERVERS, DNS_SUFFIX, FILE_HASSIO_DNS
+from .const import ATTR_SERVERS, ATTR_VERSION, DNS_SUFFIX, FILE_HASSIO_DNS
 from .coresys import CoreSys, CoreSysAttributes
 from .docker.dns import DockerDNS
 from .docker.stats import DockerStats
@@ -42,6 +42,7 @@ class CoreDNS(JsonConfig, CoreSysAttributes):
         self.coresys: CoreSys = coresys
         self.instance: DockerDNS = DockerDNS(coresys)
         self.forwarder: DNSForward = DNSForward()
+        self.coredns_template: Optional[jinja2.Template] = None
 
         self._hosts: List[HostEntry] = []
 
@@ -116,6 +117,12 @@ class CoreDNS(JsonConfig, CoreSysAttributes):
         # Start DNS forwarder
         self.sys_create_task(self.forwarder.start(self.sys_docker.network.dns))
 
+        # Initialize CoreDNS Template
+        try:
+            self.coredns_template = jinja2.Template(COREDNS_TMPL.read_text())
+        except OSError as err:
+            _LOGGER.error("Can't read coredns.tmpl: %s", err)
+
         # Run CoreDNS
         with suppress(CoreDNSError):
             if await self.instance.is_running():
@@ -208,24 +215,17 @@ class CoreDNS(JsonConfig, CoreSysAttributes):
         """Write CoreDNS config."""
         dns_servers: List[str] = []
 
-        # Load Template
-        try:
-            corefile_template: Template = Template(COREDNS_TMPL.read_text())
-        except OSError as err:
-            _LOGGER.error("Can't read coredns template file: %s", err)
-            raise CoreDNSError() from None
-
         # Prepare DNS serverlist: Prio 1 Manual, Prio 2 Local, Prio 3 Fallback
         local_dns: List[str] = self.sys_host.network.dns_servers or ["dns://127.0.0.11"]
-        servers: List[str] = self.servers + local_dns + DNS_SERVERS
+        servers: List[str] = self.servers + local_dns
 
         _LOGGER.debug(
-            "config-dns = %s, local-dns = %s , backup-dns = %s",
+            "config-dns = %s, local-dns = %s , backup-dns = CloudFlare DoT",
             self.servers,
             local_dns,
-            DNS_SERVERS,
         )
 
+        # Make sure, they are valid
         for server in servers:
             try:
                 dns_url(server)
@@ -235,7 +235,7 @@ class CoreDNS(JsonConfig, CoreSysAttributes):
                 _LOGGER.warning("Ignore invalid DNS Server: %s", server)
 
         # Generate config file
-        data = corefile_template.safe_substitute(servers=" ".join(dns_servers))
+        data = self.coredns_template.render(locals=dns_servers)
 
         try:
             self.corefile.write_text(data)