okhttp3.internal.http2.Http2Reader Maven / Gradle / Ivy
/*
* Copyright (C) 2011 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 okhttp3.internal.http2;
import java.io.Closeable;
import java.io.IOException;
import java.util.List;
import java.util.logging.Logger;
import okio.Buffer;
import okio.BufferedSource;
import okio.ByteString;
import okio.Source;
import okio.Timeout;
import static java.util.logging.Level.FINE;
import static okhttp3.internal.Util.format;
import static okhttp3.internal.http2.Http2.CONNECTION_PREFACE;
import static okhttp3.internal.http2.Http2.FLAG_ACK;
import static okhttp3.internal.http2.Http2.FLAG_COMPRESSED;
import static okhttp3.internal.http2.Http2.FLAG_END_HEADERS;
import static okhttp3.internal.http2.Http2.FLAG_END_STREAM;
import static okhttp3.internal.http2.Http2.FLAG_PADDED;
import static okhttp3.internal.http2.Http2.FLAG_PRIORITY;
import static okhttp3.internal.http2.Http2.INITIAL_MAX_FRAME_SIZE;
import static okhttp3.internal.http2.Http2.TYPE_CONTINUATION;
import static okhttp3.internal.http2.Http2.TYPE_DATA;
import static okhttp3.internal.http2.Http2.TYPE_GOAWAY;
import static okhttp3.internal.http2.Http2.TYPE_HEADERS;
import static okhttp3.internal.http2.Http2.TYPE_PING;
import static okhttp3.internal.http2.Http2.TYPE_PRIORITY;
import static okhttp3.internal.http2.Http2.TYPE_PUSH_PROMISE;
import static okhttp3.internal.http2.Http2.TYPE_RST_STREAM;
import static okhttp3.internal.http2.Http2.TYPE_SETTINGS;
import static okhttp3.internal.http2.Http2.TYPE_WINDOW_UPDATE;
import static okhttp3.internal.http2.Http2.frameLog;
import static okhttp3.internal.http2.Http2.ioException;
import static okio.ByteString.EMPTY;
/**
* Reads HTTP/2 transport frames.
*
* This implementation assumes we do not send an increased {@link Settings#getMaxFrameSize frame
* size setting} to the peer. Hence, we expect all frames to have a max length of {@link
* Http2#INITIAL_MAX_FRAME_SIZE}.
*/
final class Http2Reader implements Closeable {
static final Logger logger = Logger.getLogger(Http2.class.getName());
private final BufferedSource source;
private final ContinuationSource continuation;
private final boolean client;
// Visible for testing.
final Hpack.Reader hpackReader;
/** Creates a frame reader with max header table size of 4096. */
Http2Reader(BufferedSource source, boolean client) {
this.source = source;
this.client = client;
this.continuation = new ContinuationSource(this.source);
this.hpackReader = new Hpack.Reader(4096, continuation);
}
public void readConnectionPreface(Handler handler) throws IOException {
if (client) {
// The client reads the initial SETTINGS frame.
if (!nextFrame(true, handler)) {
throw ioException("Required SETTINGS preface not received");
}
} else {
// The server reads the CONNECTION_PREFACE byte string.
ByteString connectionPreface = source.readByteString(CONNECTION_PREFACE.size());
if (logger.isLoggable(FINE)) logger.fine(format("<< CONNECTION %s", connectionPreface.hex()));
if (!CONNECTION_PREFACE.equals(connectionPreface)) {
throw ioException("Expected a connection header but was %s", connectionPreface.utf8());
}
}
}
public boolean nextFrame(boolean requireSettings, Handler handler) throws IOException {
try {
source.require(9); // Frame header size
} catch (IOException e) {
return false; // This might be a normal socket close.
}
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Length (24) |
// +---------------+---------------+---------------+
// | Type (8) | Flags (8) |
// +-+-+-----------+---------------+-------------------------------+
// |R| Stream Identifier (31) |
// +=+=============================================================+
// | Frame Payload (0...) ...
// +---------------------------------------------------------------+
int length = readMedium(source);
if (length < 0 || length > INITIAL_MAX_FRAME_SIZE) {
throw ioException("FRAME_SIZE_ERROR: %s", length);
}
byte type = (byte) (source.readByte() & 0xff);
if (requireSettings && type != TYPE_SETTINGS) {
throw ioException("Expected a SETTINGS frame but was %s", type);
}
byte flags = (byte) (source.readByte() & 0xff);
int streamId = (source.readInt() & 0x7fffffff); // Ignore reserved bit.
if (logger.isLoggable(FINE)) logger.fine(frameLog(true, streamId, length, type, flags));
switch (type) {
case TYPE_DATA:
readData(handler, length, flags, streamId);
break;
case TYPE_HEADERS:
readHeaders(handler, length, flags, streamId);
break;
case TYPE_PRIORITY:
readPriority(handler, length, flags, streamId);
break;
case TYPE_RST_STREAM:
readRstStream(handler, length, flags, streamId);
break;
case TYPE_SETTINGS:
readSettings(handler, length, flags, streamId);
break;
case TYPE_PUSH_PROMISE:
readPushPromise(handler, length, flags, streamId);
break;
case TYPE_PING:
readPing(handler, length, flags, streamId);
break;
case TYPE_GOAWAY:
readGoAway(handler, length, flags, streamId);
break;
case TYPE_WINDOW_UPDATE:
readWindowUpdate(handler, length, flags, streamId);
break;
default:
// Implementations MUST discard frames that have unknown or unsupported types.
source.skip(length);
}
return true;
}
private void readHeaders(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) throw ioException("PROTOCOL_ERROR: TYPE_HEADERS streamId == 0");
boolean endStream = (flags & FLAG_END_STREAM) != 0;
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
if ((flags & FLAG_PRIORITY) != 0) {
readPriority(handler, streamId);
length -= 5; // account for above read.
}
length = lengthWithoutPadding(length, flags, padding);
List headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.headers(endStream, streamId, -1, headerBlock);
}
private List readHeaderBlock(int length, short padding, byte flags, int streamId)
throws IOException {
continuation.length = continuation.left = length;
continuation.padding = padding;
continuation.flags = flags;
continuation.streamId = streamId;
// TODO: Concat multi-value headers with 0x0, except COOKIE, which uses 0x3B, 0x20.
// http://tools.ietf.org/html/draft-ietf-httpbis-http2-17#section-8.1.2.5
hpackReader.readHeaders();
return hpackReader.getAndResetHeaderList();
}
private void readData(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) throw ioException("PROTOCOL_ERROR: TYPE_DATA streamId == 0");
// TODO: checkState open or half-closed (local) or raise STREAM_CLOSED
boolean inFinished = (flags & FLAG_END_STREAM) != 0;
boolean gzipped = (flags & FLAG_COMPRESSED) != 0;
if (gzipped) {
throw ioException("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
length = lengthWithoutPadding(length, flags, padding);
handler.data(inFinished, streamId, source, length);
source.skip(padding);
}
private void readPriority(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length != 5) throw ioException("TYPE_PRIORITY length: %d != 5", length);
if (streamId == 0) throw ioException("TYPE_PRIORITY streamId == 0");
readPriority(handler, streamId);
}
private void readPriority(Handler handler, int streamId) throws IOException {
int w1 = source.readInt();
boolean exclusive = (w1 & 0x80000000) != 0;
int streamDependency = (w1 & 0x7fffffff);
int weight = (source.readByte() & 0xff) + 1;
handler.priority(streamId, streamDependency, weight, exclusive);
}
private void readRstStream(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length != 4) throw ioException("TYPE_RST_STREAM length: %d != 4", length);
if (streamId == 0) throw ioException("TYPE_RST_STREAM streamId == 0");
int errorCodeInt = source.readInt();
ErrorCode errorCode = ErrorCode.fromHttp2(errorCodeInt);
if (errorCode == null) {
throw ioException("TYPE_RST_STREAM unexpected error code: %d", errorCodeInt);
}
handler.rstStream(streamId, errorCode);
}
private void readSettings(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId != 0) throw ioException("TYPE_SETTINGS streamId != 0");
if ((flags & FLAG_ACK) != 0) {
if (length != 0) throw ioException("FRAME_SIZE_ERROR ack frame should be empty!");
handler.ackSettings();
return;
}
if (length % 6 != 0) throw ioException("TYPE_SETTINGS length %% 6 != 0: %s", length);
Settings settings = new Settings();
for (int i = 0; i < length; i += 6) {
int id = source.readShort() & 0xFFFF;
int value = source.readInt();
switch (id) {
case 1: // SETTINGS_HEADER_TABLE_SIZE
break;
case 2: // SETTINGS_ENABLE_PUSH
if (value != 0 && value != 1) {
throw ioException("PROTOCOL_ERROR SETTINGS_ENABLE_PUSH != 0 or 1");
}
break;
case 3: // SETTINGS_MAX_CONCURRENT_STREAMS
id = 4; // Renumbered in draft 10.
break;
case 4: // SETTINGS_INITIAL_WINDOW_SIZE
id = 7; // Renumbered in draft 10.
if (value < 0) {
throw ioException("PROTOCOL_ERROR SETTINGS_INITIAL_WINDOW_SIZE > 2^31 - 1");
}
break;
case 5: // SETTINGS_MAX_FRAME_SIZE
if (value < INITIAL_MAX_FRAME_SIZE || value > 16777215) {
throw ioException("PROTOCOL_ERROR SETTINGS_MAX_FRAME_SIZE: %s", value);
}
break;
case 6: // SETTINGS_MAX_HEADER_LIST_SIZE
break; // Advisory only, so ignored.
default:
break; // Must ignore setting with unknown id.
}
settings.set(id, value);
}
handler.settings(false, settings);
}
private void readPushPromise(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) {
throw ioException("PROTOCOL_ERROR: TYPE_PUSH_PROMISE streamId == 0");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
int promisedStreamId = source.readInt() & 0x7fffffff;
length -= 4; // account for above read.
length = lengthWithoutPadding(length, flags, padding);
List headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.pushPromise(streamId, promisedStreamId, headerBlock);
}
private void readPing(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length != 8) throw ioException("TYPE_PING length != 8: %s", length);
if (streamId != 0) throw ioException("TYPE_PING streamId != 0");
int payload1 = source.readInt();
int payload2 = source.readInt();
boolean ack = (flags & FLAG_ACK) != 0;
handler.ping(ack, payload1, payload2);
}
private void readGoAway(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length < 8) throw ioException("TYPE_GOAWAY length < 8: %s", length);
if (streamId != 0) throw ioException("TYPE_GOAWAY streamId != 0");
int lastStreamId = source.readInt();
int errorCodeInt = source.readInt();
int opaqueDataLength = length - 8;
ErrorCode errorCode = ErrorCode.fromHttp2(errorCodeInt);
if (errorCode == null) {
throw ioException("TYPE_GOAWAY unexpected error code: %d", errorCodeInt);
}
ByteString debugData = EMPTY;
if (opaqueDataLength > 0) { // Must read debug data in order to not corrupt the connection.
debugData = source.readByteString(opaqueDataLength);
}
handler.goAway(lastStreamId, errorCode, debugData);
}
private void readWindowUpdate(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length != 4) throw ioException("TYPE_WINDOW_UPDATE length !=4: %s", length);
long increment = (source.readInt() & 0x7fffffffL);
if (increment == 0) throw ioException("windowSizeIncrement was 0", increment);
handler.windowUpdate(streamId, increment);
}
@Override public void close() throws IOException {
source.close();
}
/**
* Decompression of the header block occurs above the framing layer. This class lazily reads
* continuation frames as they are needed by {@link Hpack.Reader#readHeaders()}.
*/
static final class ContinuationSource implements Source {
private final BufferedSource source;
int length;
byte flags;
int streamId;
int left;
short padding;
ContinuationSource(BufferedSource source) {
this.source = source;
}
@Override public long read(Buffer sink, long byteCount) throws IOException {
while (left == 0) {
source.skip(padding);
padding = 0;
if ((flags & FLAG_END_HEADERS) != 0) return -1;
readContinuationHeader();
// TODO: test case for empty continuation header?
}
long read = source.read(sink, Math.min(byteCount, left));
if (read == -1) return -1;
left -= read;
return read;
}
@Override public Timeout timeout() {
return source.timeout();
}
@Override public void close() throws IOException {
}
private void readContinuationHeader() throws IOException {
int previousStreamId = streamId;
length = left = readMedium(source);
byte type = (byte) (source.readByte() & 0xff);
flags = (byte) (source.readByte() & 0xff);
if (logger.isLoggable(FINE)) logger.fine(frameLog(true, streamId, length, type, flags));
streamId = (source.readInt() & 0x7fffffff);
if (type != TYPE_CONTINUATION) throw ioException("%s != TYPE_CONTINUATION", type);
if (streamId != previousStreamId) throw ioException("TYPE_CONTINUATION streamId changed");
}
}
static int readMedium(BufferedSource source) throws IOException {
return (source.readByte() & 0xff) << 16
| (source.readByte() & 0xff) << 8
| (source.readByte() & 0xff);
}
static int lengthWithoutPadding(int length, byte flags, short padding)
throws IOException {
if ((flags & FLAG_PADDED) != 0) length--; // Account for reading the padding length.
if (padding > length) {
throw ioException("PROTOCOL_ERROR padding %s > remaining length %s", padding, length);
}
return (short) (length - padding);
}
interface Handler {
void data(boolean inFinished, int streamId, BufferedSource source, int length)
throws IOException;
/**
* Create or update incoming headers, creating the corresponding streams if necessary. Frames
* that trigger this are HEADERS and PUSH_PROMISE.
*
* @param inFinished true if the sender will not send further frames.
* @param streamId the stream owning these headers.
* @param associatedStreamId the stream that triggered the sender to create this stream.
*/
void headers(boolean inFinished, int streamId, int associatedStreamId,
List headerBlock);
void rstStream(int streamId, ErrorCode errorCode);
void settings(boolean clearPrevious, Settings settings);
/** HTTP/2 only. */
void ackSettings();
/**
* Read a connection-level ping from the peer. {@code ack} indicates this is a reply. The data
* in {@code payload1} and {@code payload2} opaque binary, and there are no rules on the
* content.
*/
void ping(boolean ack, int payload1, int payload2);
/**
* The peer tells us to stop creating streams. It is safe to replay streams with {@code ID >
* lastGoodStreamId} on a new connection. In- flight streams with {@code ID <=
* lastGoodStreamId} can only be replayed on a new connection if they are idempotent.
*
* @param lastGoodStreamId the last stream ID the peer processed before sending this message. If
* {@code lastGoodStreamId} is zero, the peer processed no frames.
* @param errorCode reason for closing the connection.
* @param debugData only valid for HTTP/2; opaque debug data to send.
*/
void goAway(int lastGoodStreamId, ErrorCode errorCode, ByteString debugData);
/**
* Notifies that an additional {@code windowSizeIncrement} bytes can be sent on {@code
* streamId}, or the connection if {@code streamId} is zero.
*/
void windowUpdate(int streamId, long windowSizeIncrement);
/**
* Called when reading a headers or priority frame. This may be used to change the stream's
* weight from the default (16) to a new value.
*
* @param streamId stream which has a priority change.
* @param streamDependency the stream ID this stream is dependent on.
* @param weight relative proportion of priority in [1..256].
* @param exclusive inserts this stream ID as the sole child of {@code streamDependency}.
*/
void priority(int streamId, int streamDependency, int weight, boolean exclusive);
/**
* HTTP/2 only. Receive a push promise header block. A push promise contains all the headers
* that pertain to a server-initiated request, and a {@code promisedStreamId} to which response
* frames will be delivered. Push promise frames are sent as a part of the response to {@code
* streamId}.
*
* @param streamId client-initiated stream ID. Must be an odd number.
* @param promisedStreamId server-initiated stream ID. Must be an even number.
* @param requestHeaders minimally includes {@code :method}, {@code :scheme}, {@code
* :authority}, and (@code :path}.
*/
void pushPromise(int streamId, int promisedStreamId, List requestHeaders)
throws IOException;
/**
* HTTP/2 only. Expresses that resources for the connection or a client- initiated stream are
* available from a different network location or protocol configuration.
*
* See alt-svc
*
* @param streamId when a client-initiated stream ID (odd number), the origin of this alternate
* service is the origin of the stream. When zero, the origin is specified in the {@code origin}
* parameter.
* @param origin when present, the origin is
* typically represented as a combination of scheme, host and port. When empty, the origin is
* that of the {@code streamId}.
* @param protocol an ALPN protocol, such as {@code h2}.
* @param host an IP address or hostname.
* @param port the IP port associated with the service.
* @param maxAge time in seconds that this alternative is considered fresh.
*/
void alternateService(int streamId, String origin, ByteString protocol, String host, int port,
long maxAge);
}
}