okhttp3.internal.ws.WebSocketProtocol Maven / Gradle / Ivy
/*
* Copyright (C) 2014 Square, 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.
*/
package okhttp3.internal.ws;
import okio.Buffer;
import okio.ByteString;
public final class WebSocketProtocol {
/** Magic value which must be appended to the key in a response header. */
static final String ACCEPT_MAGIC = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
/*
Each frame starts with two bytes of data.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-------+ +-+-------------+
|F|R|R|R| OP | |M| LENGTH |
|I|S|S|S| CODE | |A| |
|N|V|V|V| | |S| |
| |1|2|3| | |K| |
+-+-+-+-+-------+ +-+-------------+
*/
/** Byte 0 flag for whether this is the final fragment in a message. */
static final int B0_FLAG_FIN = 0b10000000;
/** Byte 0 reserved flag 1. Must be 0 unless negotiated otherwise. */
static final int B0_FLAG_RSV1 = 0b01000000;
/** Byte 0 reserved flag 2. Must be 0 unless negotiated otherwise. */
static final int B0_FLAG_RSV2 = 0b00100000;
/** Byte 0 reserved flag 3. Must be 0 unless negotiated otherwise. */
static final int B0_FLAG_RSV3 = 0b00010000;
/** Byte 0 mask for the frame opcode. */
static final int B0_MASK_OPCODE = 0b00001111;
/** Flag in the opcode which indicates a control frame. */
static final int OPCODE_FLAG_CONTROL = 0b00001000;
/**
* Byte 1 flag for whether the payload data is masked. If this flag is set, the next four
* bytes represent the mask key. These bytes appear after any additional bytes specified by {@link
* #B1_MASK_LENGTH}.
*/
static final int B1_FLAG_MASK = 0b10000000;
/**
* Byte 1 mask for the payload length.
If this value is {@link #PAYLOAD_SHORT}, the next two
* bytes represent the length. If this value is {@link #PAYLOAD_LONG}, the next eight bytes
* represent the length.
*/
static final int B1_MASK_LENGTH = 0b01111111;
static final int OPCODE_CONTINUATION = 0x0;
static final int OPCODE_TEXT = 0x1;
static final int OPCODE_BINARY = 0x2;
static final int OPCODE_CONTROL_CLOSE = 0x8;
static final int OPCODE_CONTROL_PING = 0x9;
static final int OPCODE_CONTROL_PONG = 0xa;
/**
* Maximum length of frame payload. Larger payloads, if supported by the frame type, can use the
* special values {@link #PAYLOAD_SHORT} or {@link #PAYLOAD_LONG}.
*/
static final long PAYLOAD_BYTE_MAX = 125L;
/** Maximum length of close message in bytes. */
static final long CLOSE_MESSAGE_MAX = PAYLOAD_BYTE_MAX - 2;
/**
* Value for {@link #B1_MASK_LENGTH} which indicates the next two bytes are the unsigned length.
*/
static final int PAYLOAD_SHORT = 126;
/** Maximum length of a frame payload to be denoted as {@link #PAYLOAD_SHORT}. */
static final long PAYLOAD_SHORT_MAX = 0xffffL;
/**
* Value for {@link #B1_MASK_LENGTH} which indicates the next eight bytes are the unsigned
* length.
*/
static final int PAYLOAD_LONG = 127;
/** Used when an unchecked exception was thrown in a listener. */
static final int CLOSE_CLIENT_GOING_AWAY = 1001;
/** Used when an empty close frame was received (i.e., without a status code). */
static final int CLOSE_NO_STATUS_CODE = 1005;
static void toggleMask(Buffer.UnsafeCursor cursor, byte[] key) {
int keyIndex = 0;
int keyLength = key.length;
do {
byte[] buffer = cursor.data;
for (int i = cursor.start, end = cursor.end; i < end; i++, keyIndex++) {
keyIndex %= keyLength; // Reassign to prevent overflow breaking counter.
buffer[i] = (byte) (buffer[i] ^ key[keyIndex]);
}
} while (cursor.next() != -1);
}
static String closeCodeExceptionMessage(int code) {
if (code < 1000 || code >= 5000) {
return "Code must be in range [1000,5000): " + code;
} else if ((code >= 1004 && code <= 1006) || (code >= 1012 && code <= 2999)) {
return "Code " + code + " is reserved and may not be used.";
} else {
return null;
}
}
static void validateCloseCode(int code) {
String message = closeCodeExceptionMessage(code);
if (message != null) throw new IllegalArgumentException(message);
}
public static String acceptHeader(String key) {
return ByteString.encodeUtf8(key + WebSocketProtocol.ACCEPT_MAGIC).sha1().base64();
}
private WebSocketProtocol() {
throw new AssertionError("No instances.");
}
}