stream {
  js_import /etc/nginx/nginx-dns/njs.d/dns/dns.js;

  # The $dns_qname variable can be populated by preread calls, and can be used for DNS routing
  js_set $dns_qname dns.get_qname;
  
  # The DNS response packet, if we're blocking the domain, this will be set.
  js_set $dns_response dns.get_response;

  limit_conn_zone $binary_remote_addr zone=dns-addr:30m;

  # When doing DNS routing, use $dns_qname to map the questions to the upstream pools.
  map $dns_qname $upstream {
    include /etc/nginx/domains.txt;
    default blocked;
  }

  map $dns_qname $upstream_v6 {
    include /etc/nginx/domains_v6.txt;
    default blocked;
  }

  # upstream pool for blocked requests (returns nxdomain)
  upstream blocked {
    server 127.0.0.1:9953;
  }

  upstream dns_server {
    server 127.0.0.1:53;
  }

  upstream dns_server_v6 {
    server [::1]:53;
  }

  server {
    listen 53;
    listen 53 udp;
    proxy_responses 1;
    proxy_timeout 2s;
    proxy_upload_rate 10k;
    proxy_download_rate 10k;
#    set_real_ip_from 0.0.0.0;
    js_preread dns.preread_dns_request;
    proxy_pass $upstream;
    access_log off;
    error_log /dev/null;
  }

  server {
    listen [::]:53 ipv6only=on;
    listen [::]:53 udp ipv6only=on;
    proxy_responses 1;
    proxy_timeout 2s;
    proxy_upload_rate 10k;
    proxy_download_rate 10k;
#    set_real_ip_from [::];
    js_preread dns.preread_dns_request;
    proxy_pass $upstream_v6;
    access_log off;
    error_log /dev/null;
  }

  # Server for responding to blocked responses
  server {
    listen 127.0.0.1:9953;
    listen 127.0.0.1:9953 udp;
    limit_conn dns-addr 3;
    proxy_responses 1;
    js_preread dns.preread_dns_request;
    access_log off;
    error_log /dev/null;
    return $dns_response;
  }
}