content: /*
   * Copyright (C) 2013 The Android Open Source Project
   *
   * 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 com.android.server.firewall;
  
  import android.content.ComponentName;
  import android.content.Intent;
  import android.net.Uri;
  import org.xmlpull.v1.XmlPullParser;
  import org.xmlpull.v1.XmlPullParserException;
  
  import java.io.IOException;
  
  class PortFilter implements Filter {
      private static final String ATTR_EQUALS = "equals";
      private static final String ATTR_MIN = "min";
      private static final String ATTR_MAX = "max";
  
      private static final int NO_BOUND = -1;
  
      // both bounds are inclusive
      private final int mLowerBound;
      private final int mUpperBound;
  
      private PortFilter(int lowerBound, int upperBound) {
          mLowerBound = lowerBound;
          mUpperBound = upperBound;
      }
  
      @Override
      public boolean matches(IntentFirewall ifw, ComponentName resolvedComponent, Intent intent,
              int callerUid, int callerPid, String resolvedType, int receivingUid) {
          int port = -1;
          Uri uri = intent.getData();
          if (uri != null) {
              port = uri.getPort();
          }
          return port != -1 &&
                  (mLowerBound == NO_BOUND || mLowerBound <= port) &&
                  (mUpperBound == NO_BOUND || mUpperBound >= port);
      }
  
      public static final FilterFactory FACTORY = new FilterFactory("port") {
          @Override
          public Filter newFilter(XmlPullParser parser)
                  throws IOException, XmlPullParserException {
              int lowerBound = NO_BOUND;
              int upperBound = NO_BOUND;
  
              String equalsValue = parser.getAttributeValue(null, ATTR_EQUALS);
              if (equalsValue != null) {
                  int value;
                  try {
                      value = Integer.parseInt(equalsValue);
                  } catch (NumberFormatException ex) {
                      throw new XmlPullParserException("Invalid port value: " + equalsValue,
                              parser, null);
                  }
                  lowerBound = value;
                  upperBound = value;
              }
  
              String lowerBoundString = parser.getAttributeValue(null, ATTR_MIN);
              String upperBoundString = parser.getAttributeValue(null, ATTR_MAX);
              if (lowerBoundString != null || upperBoundString != null) {
                  if (equalsValue != null) {
                      throw new XmlPullParserException(
                              "Port filter cannot use both equals and range filtering",
                              parser, null);
                  }
  
                  if (lowerBoundString != null) {
                      try {
                          lowerBound = Integer.parseInt(lowerBoundString);
                      } catch (NumberFormatException ex) {
                          throw new XmlPullParserException(
                                  "Invalid minimum port value: " + lowerBoundString,
                                  parser, null);
                      }
                  }
  
                  if (upperBoundString != null) {
                      try {
                          upperBound = Integer.parseInt(upperBoundString);
                      } catch (NumberFormatException ex) {
                          throw new XmlPullParserException(
                                  "Invalid maximum port value: " + upperBoundString,
                                  parser, null);
                      }
                  }
              }
  
              // an empty port filter is explicitly allowed, and checks for the existence of a port
              return new PortFilter(lowerBound, upperBound);
          }
      };
  }
  