1/*
2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.incubator.http.internal.websocket;
27
28import jdk.incubator.http.internal.common.MinimalFuture;
29
30import java.io.IOException;
31import java.net.URI;
32import java.net.URISyntaxException;
33import jdk.incubator.http.HttpClient;
34import jdk.incubator.http.HttpClient.Version;
35import jdk.incubator.http.HttpHeaders;
36import jdk.incubator.http.HttpRequest;
37import jdk.incubator.http.HttpResponse;
38import jdk.incubator.http.HttpResponse.BodyHandler;
39import jdk.incubator.http.WebSocketHandshakeException;
40import jdk.incubator.http.internal.common.Pair;
41
42import java.nio.charset.StandardCharsets;
43import java.security.MessageDigest;
44import java.security.NoSuchAlgorithmException;
45import java.security.SecureRandom;
46import java.time.Duration;
47import java.util.Base64;
48import java.util.Collection;
49import java.util.Collections;
50import java.util.LinkedHashSet;
51import java.util.List;
52import java.util.Optional;
53import java.util.Set;
54import java.util.TreeSet;
55import java.util.concurrent.CompletableFuture;
56import java.util.stream.Collectors;
57
58import static java.lang.String.format;
59import static jdk.incubator.http.internal.common.Utils.isValidName;
60import static jdk.incubator.http.internal.common.Utils.stringOf;
61
62final class OpeningHandshake {
63
64    private static final String HEADER_CONNECTION = "Connection";
65    private static final String HEADER_UPGRADE    = "Upgrade";
66    private static final String HEADER_ACCEPT     = "Sec-WebSocket-Accept";
67    private static final String HEADER_EXTENSIONS = "Sec-WebSocket-Extensions";
68    private static final String HEADER_KEY        = "Sec-WebSocket-Key";
69    private static final String HEADER_PROTOCOL   = "Sec-WebSocket-Protocol";
70    private static final String HEADER_VERSION    = "Sec-WebSocket-Version";
71
72    private static final Set<String> FORBIDDEN_HEADERS;
73
74    static {
75        FORBIDDEN_HEADERS = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
76        FORBIDDEN_HEADERS.addAll(List.of(HEADER_ACCEPT,
77                                         HEADER_EXTENSIONS,
78                                         HEADER_KEY,
79                                         HEADER_PROTOCOL,
80                                         HEADER_VERSION));
81    }
82
83    private static final SecureRandom srandom = new SecureRandom();
84
85    private final MessageDigest sha1;
86    private final HttpClient client;
87
88    {
89        try {
90            sha1 = MessageDigest.getInstance("SHA-1");
91        } catch (NoSuchAlgorithmException e) {
92            // Shouldn't happen: SHA-1 must be available in every Java platform
93            // implementation
94            throw new InternalError("Minimum requirements", e);
95        }
96    }
97
98    private final HttpRequest request;
99    private final Collection<String> subprotocols;
100    private final String nonce;
101
102    OpeningHandshake(BuilderImpl b) {
103        this.client = b.getClient();
104        URI httpURI = createRequestURI(b.getUri());
105        HttpRequest.Builder requestBuilder = HttpRequest.newBuilder(httpURI);
106        Duration connectTimeout = b.getConnectTimeout();
107        if (connectTimeout != null) {
108            requestBuilder.timeout(connectTimeout);
109        }
110        for (Pair<String, String> p : b.getHeaders()) {
111            if (FORBIDDEN_HEADERS.contains(p.first)) {
112                throw illegal("Illegal header: " + p.first);
113            }
114            requestBuilder.header(p.first, p.second);
115        }
116        this.subprotocols = createRequestSubprotocols(b.getSubprotocols());
117        if (!this.subprotocols.isEmpty()) {
118            String p = this.subprotocols.stream().collect(Collectors.joining(", "));
119            requestBuilder.header(HEADER_PROTOCOL, p);
120        }
121        requestBuilder.header(HEADER_VERSION, "13"); // WebSocket's lucky number
122        this.nonce = createNonce();
123        requestBuilder.header(HEADER_KEY, this.nonce);
124        // Setting request version to HTTP/1.1 forcibly, since it's not possible
125        // to upgrade from HTTP/2 to WebSocket (as of August 2016):
126        //
127        //     https://tools.ietf.org/html/draft-hirano-httpbis-websocket-over-http2-00
128        this.request = requestBuilder.version(Version.HTTP_1_1).GET().build();
129        WebSocketRequest r = (WebSocketRequest) this.request;
130        r.isWebSocket(true);
131        r.setSystemHeader(HEADER_UPGRADE, "websocket");
132        r.setSystemHeader(HEADER_CONNECTION, "Upgrade");
133    }
134
135    private static Collection<String> createRequestSubprotocols(
136            Collection<String> subprotocols)
137    {
138        LinkedHashSet<String> sp = new LinkedHashSet<>(subprotocols.size(), 1);
139        for (String s : subprotocols) {
140            if (s.trim().isEmpty() || !isValidName(s)) {
141                throw illegal("Bad subprotocol syntax: " + s);
142            }
143            if (!sp.add(s)) {
144                throw illegal("Duplicating subprotocol: " + s);
145            }
146        }
147        return Collections.unmodifiableCollection(sp);
148    }
149
150    /*
151     * Checks the given URI for being a WebSocket URI and translates it into a
152     * target HTTP URI for the Opening Handshake.
153     *
154     * https://tools.ietf.org/html/rfc6455#section-3
155     */
156    private static URI createRequestURI(URI uri) {
157        // TODO: check permission for WebSocket URI and translate it into
158        // http/https permission
159        String s = uri.getScheme(); // The scheme might be null (i.e. undefined)
160        if (!("ws".equalsIgnoreCase(s) || "wss".equalsIgnoreCase(s))
161                || uri.getFragment() != null)
162        {
163            throw illegal("Bad URI: " + uri);
164        }
165        String scheme = "ws".equalsIgnoreCase(s) ? "http" : "https";
166        try {
167            return new URI(scheme,
168                           uri.getUserInfo(),
169                           uri.getHost(),
170                           uri.getPort(),
171                           uri.getPath(),
172                           uri.getQuery(),
173                           null); // No fragment
174        } catch (URISyntaxException e) {
175            // Shouldn't happen: URI invariant
176            throw new InternalError(e);
177        }
178    }
179
180    CompletableFuture<Result> send() {
181        return client.sendAsync(this.request, BodyHandler.<Void>discard(null))
182                .thenCompose(this::resultFrom);
183    }
184
185    /*
186     * The result of the opening handshake.
187     */
188    static final class Result {
189
190        final String subprotocol;
191        final RawChannel channel;
192
193        private Result(String subprotocol, RawChannel channel) {
194            this.subprotocol = subprotocol;
195            this.channel = channel;
196        }
197    }
198
199    private CompletableFuture<Result> resultFrom(HttpResponse<?> response) {
200        // Do we need a special treatment for SSLHandshakeException?
201        // Namely, invoking
202        //
203        //     Listener.onClose(StatusCodes.TLS_HANDSHAKE_FAILURE, "")
204        //
205        // See https://tools.ietf.org/html/rfc6455#section-7.4.1
206        Result result = null;
207        Exception exception = null;
208        try {
209            result = handleResponse(response);
210        } catch (IOException e) {
211            exception = e;
212        } catch (Exception e) {
213            exception = new WebSocketHandshakeException(response).initCause(e);
214        }
215        if (exception == null) {
216            return MinimalFuture.completedFuture(result);
217        }
218        try {
219            ((RawChannel.Provider) response).rawChannel().close();
220        } catch (IOException e) {
221            exception.addSuppressed(e);
222        }
223        return MinimalFuture.failedFuture(exception);
224    }
225
226    private Result handleResponse(HttpResponse<?> response) throws IOException {
227        // By this point all redirects, authentications, etc. (if any) MUST have
228        // been done by the HttpClient used by the WebSocket; so only 101 is
229        // expected
230        int c = response.statusCode();
231        if (c != 101) {
232            throw checkFailed("Unexpected HTTP response status code " + c);
233        }
234        HttpHeaders headers = response.headers();
235        String upgrade = requireSingle(headers, HEADER_UPGRADE);
236        if (!upgrade.equalsIgnoreCase("websocket")) {
237            throw checkFailed("Bad response field: " + HEADER_UPGRADE);
238        }
239        String connection = requireSingle(headers, HEADER_CONNECTION);
240        if (!connection.equalsIgnoreCase("Upgrade")) {
241            throw checkFailed("Bad response field: " + HEADER_CONNECTION);
242        }
243        requireAbsent(headers, HEADER_VERSION);
244        requireAbsent(headers, HEADER_EXTENSIONS);
245        String x = this.nonce + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
246        this.sha1.update(x.getBytes(StandardCharsets.ISO_8859_1));
247        String expected = Base64.getEncoder().encodeToString(this.sha1.digest());
248        String actual = requireSingle(headers, HEADER_ACCEPT);
249        if (!actual.trim().equals(expected)) {
250            throw checkFailed("Bad " + HEADER_ACCEPT);
251        }
252        String subprotocol = checkAndReturnSubprotocol(headers);
253        RawChannel channel = ((RawChannel.Provider) response).rawChannel();
254        return new Result(subprotocol, channel);
255    }
256
257    private String checkAndReturnSubprotocol(HttpHeaders responseHeaders)
258            throws CheckFailedException
259    {
260        Optional<String> opt = responseHeaders.firstValue(HEADER_PROTOCOL);
261        if (!opt.isPresent()) {
262            // If there is no such header in the response, then the server
263            // doesn't want to use any subprotocol
264            return "";
265        }
266        String s = requireSingle(responseHeaders, HEADER_PROTOCOL);
267        // An empty string as a subprotocol's name is not allowed by the spec
268        // and the check below will detect such responses too
269        if (this.subprotocols.contains(s)) {
270            return s;
271        } else {
272            throw checkFailed("Unexpected subprotocol: " + s);
273        }
274    }
275
276    private static void requireAbsent(HttpHeaders responseHeaders,
277                                      String headerName)
278    {
279        List<String> values = responseHeaders.allValues(headerName);
280        if (!values.isEmpty()) {
281            throw checkFailed(format("Response field '%s' present: %s",
282                                     headerName,
283                                     stringOf(values)));
284        }
285    }
286
287    private static String requireSingle(HttpHeaders responseHeaders,
288                                        String headerName)
289    {
290        List<String> values = responseHeaders.allValues(headerName);
291        if (values.isEmpty()) {
292            throw checkFailed("Response field missing: " + headerName);
293        } else if (values.size() > 1) {
294            throw checkFailed(format("Response field '%s' multivalued: %s",
295                                     headerName,
296                                     stringOf(values)));
297        }
298        return values.get(0);
299    }
300
301    private static String createNonce() {
302        byte[] bytes = new byte[16];
303        OpeningHandshake.srandom.nextBytes(bytes);
304        return Base64.getEncoder().encodeToString(bytes);
305    }
306
307    private static IllegalArgumentException illegal(String message) {
308        return new IllegalArgumentException(message);
309    }
310
311    private static CheckFailedException checkFailed(String message) {
312        throw new CheckFailedException(message);
313    }
314}
315