jk_config/wwwroot/login.php

<?php
header("Content-type=text/json;charset=UTF-8");
$conn = mysqli_connect("localhost", "root", "R.!a@O&t9CjweWLSTr", "centralized_control_db") or die("mysql connect error!");
mysqli_query($conn, "set character set 'utf8'");
date_default_timezone_set('Asia/Shanghai');

$dataP = file_get_contents("php://input");
$arr = json_decode($dataP);

//$user_name = "2";
//$password = "eccbc87e4b5ce2fe28308fd9f2a7baf3";
//$ip = "221.0.237.194";
$user_name = "'" . $arr->userName . "'";
$password = "'" . $arr->password . "'";
$ip = "'" . $arr->ip . "'";


# 判断访问IP是否在白名单或黑名单中
$real_data = null;
$black_white_sql = $conn->query("SELECT `lists` FROM `user_list` WHERE `ip` = $ip;");
while($row1 = mysqli_fetch_array($black_white_sql, MYSQLI_ASSOC)) {
    $real_data = $row1["lists"];
}


if ( $real_data=='1' ) {
    // ip在黑名单中，禁止登录
    $res_info = "失败5次，进入黑名单";
} else {
    // ip不在黑名单中，判断账号密码是否正确
    $user_pw_sql = mysqli_query($conn, "SELECT * FROM user WHERE user_name = $user_name AND password = $password;");
    $result = $user_pw_sql->num_rows;
    if ($result == 1) {
        // 密码正确，允许登录
        $res_info = "success";
    }
    else {
        // 密码错误，判断是否需要增加登录失败的次数
        if ( $real_data == '0' ) {
            // ip在白名单中，不需要增加登录失败的次数
            $res_info = "账号或密码错误，请重新登录";
        } elseif ( is_null($real_data) ) {
            // ip不在白名单中，登录失败次数+1或者加入黑名单
            $wrong_sql = mysqli_query($conn, "SELECT `id`, `times` FROM user_var WHERE `ip` = $ip;");
            $result_var = $wrong_sql->num_rows;

            if ( $result_var=='0' ) {
                // ip第一次登录失败
                mysqli_query($conn, "INSERT INTO `user_var` (`ip`) VALUES ($ip);");
                $res_info = "第1次登录失败，超过5次将进入黑名单";
            } elseif ( $result_var=='1' ) {

                while($row2 = mysqli_fetch_array($wrong_sql, MYSQLI_ASSOC)) {
                    $id = $row2["id"];
                    $times = $row2["times"] + 1;
                }
                if ( $times == 5 ) {
                    // 已经失败5次，加入黑名单
                    mysqli_query($conn, "INSERT INTO `user_list` (`ip`, `lists`) VALUES ($ip, 1);");
                    mysqli_query($conn, "DELETE FROM `user_var` WHERE ((`id` = $id));");
                    $res_info = $times."次登录失败，进入黑名单";
                } else {
                    // 登录失败次数+1
                    mysqli_query($conn, "UPDATE `user_var` SET `times`=$times WHERE `id`=$id;");
                    $res_info = "第".$times."次登录失败，超过5次将进入黑名单";
                }
            }

        }
    }
}

$res["result"] = $res_info;
echo json_encode($res);

$conn->close();
?>