根据 gfwlist 生成 dns 污染的域名列表。用于 coredns 配置

coredns.php

<?php

function parse($str) {
  $s = ltrim($str, '|@.');
  $host = null;
  if (false !== strpos($s, '//')) {
    $url = parse_url($s);
    if (!empty($url['host'])) {
      $host = $url['host'];
    }
  } elseif (false !== ($pos = strpos($s, '/'))) {
    $host = substr($s, 0, $pos);
  } else {
    $host = $s;
  }
  if (preg_match('/^[\d\.]+$/', $host)) {  // host is ip
    return null;
  }
  $sections = explode('.', $host);
  $len = count($sections);
  $host = implode('.', [$sections[$len - 2], $sections[$len - 1]]);
  return false === strpos($host, '*') ? $host : null;
}
//$content = base64_decode(file_get_contents('/data/gfwlist.txt'));
$content = base64_decode(file_get_contents('https://raw.githubusercontent.com/gfwlist/gfwlist/master/gfwlist.txt'));
$pos = 0;
$result = [];
while (false != ($newpos = strpos($content, "\n", $pos + 1))) {
  $line = trim(substr($content, $pos, $newpos - $pos));
  $pos = $newpos;
  if (empty($line) || ($line{0} === '!') || false === strpos($line, '.') || false !== strpos($line, ' ')) {
    continue;
  }
  $domain = parse($line);
  if (!isset($domain)) {
    continue;
  }
  in_array($domain, $result) || ($result[] = $domain);
}
echo implode(' ', $result);