1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.conscrypt; 18 19 import static org.conscrypt.Preconditions.checkNotNull; 20 21 import java.util.Arrays; 22 import java.util.List; 23 import javax.net.ssl.SSLEngine; 24 import javax.net.ssl.SSLSocket; 25 26 /** 27 * An adapter to bridge between the native code and the {@link ApplicationProtocolSelector} API. 28 */ 29 final class ApplicationProtocolSelectorAdapter { 30 private static final int NO_PROTOCOL_SELECTED = -1; 31 32 private final SSLEngine engine; 33 private final SSLSocket socket; 34 private final ApplicationProtocolSelector selector; 35 ApplicationProtocolSelectorAdapter(SSLEngine engine, ApplicationProtocolSelector selector)36 ApplicationProtocolSelectorAdapter(SSLEngine engine, ApplicationProtocolSelector selector) { 37 this.engine = checkNotNull(engine, "engine"); 38 this.socket = null; 39 this.selector = checkNotNull(selector, "selector"); 40 } 41 ApplicationProtocolSelectorAdapter(SSLSocket socket, ApplicationProtocolSelector selector)42 ApplicationProtocolSelectorAdapter(SSLSocket socket, ApplicationProtocolSelector selector) { 43 this.engine = null; 44 this.socket = checkNotNull(socket, "socket"); 45 this.selector = checkNotNull(selector, "selector"); 46 } 47 48 /** 49 * Performs the ALPN protocol selection from the given list of length-delimited peer protocols. 50 * @param encodedProtocols the peer protocols in length-delimited form. 51 * @return If successful, returns the offset into the {@code lenghPrefixedList} array of the 52 * selected protocol (i.e. points to the length prefix). Otherwise, returns 53 * {@link #NO_PROTOCOL_SELECTED}. 54 */ selectApplicationProtocol(byte[] encodedProtocols)55 int selectApplicationProtocol(byte[] encodedProtocols) { 56 if (encodedProtocols == null || encodedProtocols.length == 0) { 57 return NO_PROTOCOL_SELECTED; 58 } 59 60 // Decode the protocols. 61 List<String> protocols = Arrays.asList(SSLUtils.decodeProtocols(encodedProtocols)); 62 63 // Select the protocol. 64 final String selected; 65 if (engine != null ) { 66 selected = selector.selectApplicationProtocol(engine, protocols); 67 } else { 68 selected = selector.selectApplicationProtocol(socket, protocols); 69 } 70 if (selected == null || selected.isEmpty()) { 71 return NO_PROTOCOL_SELECTED; 72 } 73 74 int offset = 0; 75 for (String protocol : protocols) { 76 if (selected.equals(protocol)) { 77 // Found the selected protocol. Return the index position of the beginning of 78 // the protocol. 79 return offset; 80 } 81 82 // Add 1 byte for the length prefix. 83 offset += 1 + protocol.length(); 84 } 85 86 return NO_PROTOCOL_SELECTED; 87 } 88 } 89