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/**
 * Copyright 2018 Mike Hummel
 *
 * 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.
 */
package de.mhus.lib.servlet.security;

import java.util.HashMap;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import de.mhus.lib.core.MLog;
import de.mhus.lib.core.cfg.CfgLong;
import de.mhus.lib.core.lang.LongValue;

/*

 */
public class DefaultSecurityWatch extends MLog implements SecurityApi {

	private static CfgLong CFG_MAX_PER_SEC = new CfgLong(SecurityApi.class, "maxHitsPerSecond", 1000);
	private static CfgLong CFG_MAX_IPS = new CfgLong(SecurityApi.class, "maxIPsPerSecond", 1000);
	
	private HashMap hits = new HashMap<>();
	
	long lastSec = 0;
	
	@Override
	public synchronized boolean checkHttpRequest(HttpServletRequest req, HttpServletResponse res) {
		long sec = System.currentTimeMillis() / 1000;
		
		if (lastSec != sec) {
			// cleanup
			hits.clear();
			lastSec = sec;
		}
		
		if (hits.size() > CFG_MAX_IPS.value()) {
			log().t("Blocked MAX IPS");
			return false; 
		}
		
		String ip = req.getRemoteAddr();
		LongValue hit = hits.get(ip);
		if (hit == null) {
			hit = new LongValue(0);
			hits.put(ip, hit);
		}
		long h = hit.get();
		if (h > CFG_MAX_PER_SEC.value()) {
			log().t("Blocked IP",ip);
			return false;
		}
		hit.set(h+1);
		
		return true;
	}

}