package com.walmartlabs.concord.server.security;

/*-
 * *****
 * Concord
 * -----
 * Copyright (C) 2017 - 2019 Walmart Inc.
 * -----
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =====
 */

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.util.WebUtils;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class LocalRequestFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) {
        // do nothing
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest r = WebUtils.toHttp(request);
        if (isLocalRequest(r)) {
            chain.doFilter(request, response);
        } else {
            throw new AuthenticationException("Only localhost requests are allowed");
        }
    }

    @Override
    public void destroy() {
        // do nothing
    }


    private static boolean isLocalRequest(HttpServletRequest request) throws UnknownHostException {
        InetAddress addr = InetAddress.getByName(request.getRemoteAddr());
        return addr.isAnyLocalAddress() || addr.isLoopbackAddress();
    }
}
