PHP +mysql based on IP to determine the user's city program

PHP tutorial based on IP to determine the user's city program
$servername = ' localhost ';
$dbname = ' 8684 ';  //Database tutorial name
$dbusername = ' Root '; Database user name
$dbpassword = ' 123456 ';//Database Password
 
$link =mysql Tutorial _connect ($servername, $dbusername, $ Dbpassword);
mysql_select_db ($dbname) or Die ();
mysql_query ("Set names ' GBK '");

function Get_real_ip () {
$ip =false;
if (!empty ($_server["HTTP_CLIENT_IP"])) {
$ip =$_server["Http_client_ip"];
}
if (!empty ($_server[' http_x_forwarded_for ')) {
$ips Tutorial =explode (",", $_server[' http_x_forwarded_for '));
if ($IP) {
Array_unshift ($ips, $IP);
$ip =false;
}
For ($i =0 $i <count ($ips); $i + +) {
if (!eregi ("^ (10│172.16│192.168).", $ips [$i])) {
$ip = $ips [$i];
Break;
}
}
}
$ip = $ip $ip: $_server[' remote_addr '];
List ($ip 1, $ip 2, $ip 3, $ip 4) =explode (".", $ip);
Return $ip 1*pow (256,3) + $ip 2*pow (256,2) + $ip 3*256+ $ip 4;
}
$ip =get_real_ip ();
$sql = "SELECT * from IP where start<= $ip order by start DESC limit 1";
$q =mysql_query ($sql);
$rs =mysql_fetch_array ($q);
$city = $rs ["City"];

Echo $city;