540c26bb56
Motivation: The responsibility for retaining the settings values and enforcing the settings constraints is spread out in different areas of the code and may be initialized with different values than the default specified in the RFC. This should not be allowed by default and interfaces which are responsible for maintaining/enforcing settings state should clearly indicate the restrictions that they should only be set by the codec upon receipt of a SETTINGS ACK frame. Modifications: - Encoder, Decoder, and the Headers Encoder/Decoder no longer expose public constructors that allow the default settings to be changed. - Http2HeadersDecoder#maxHeaderSize() exists to provide some bound when headers/continuation frames are being aggregated. However this is roughly the same as SETTINGS_MAX_HEADER_LIST_SIZE (besides the 32 byte octet for each header field) and can be used instead of attempting to keep the two independent values in sync. - Encoding headers now enforces SETTINGS_MAX_HEADER_LIST_SIZE at the octect level. Previously the header encoder compared the number of header key/value pairs against SETTINGS_MAX_HEADER_LIST_SIZE instead of the number of octets (plus 32 bytes overhead). - DefaultHttp2ConnectionDecoder#onData calls shouldIgnoreHeadersOrDataFrame but may swallow exceptions from this method. This means a STREAM_RST frame may not be sent when it should for an unknown stream and thus violate the RFC. The exception is no longer swallowed. Result: Default settings state is enforced and interfaces related to settings state are clarified.
82 lines
3.6 KiB
Java
82 lines
3.6 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License, version 2.0 (the
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* "License"); you may not use this file except in compliance with the License. You may obtain a
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* copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software distributed under the License
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* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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* or implied. See the License for the specific language governing permissions and limitations under
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* the License.
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*/
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package io.netty.handler.codec.http2;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.util.internal.UnstableApi;
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/**
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* Base interface for all HTTP/2 flow controllers.
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*/
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@UnstableApi
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public interface Http2FlowController {
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/**
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* Set the {@link ChannelHandlerContext} for which to apply flow control on.
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* <p>
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* This <strong>must</strong> be called to properly initialize the {@link Http2FlowController}.
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* Not calling this is considered a programming error.
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* @param ctx The {@link ChannelHandlerContext} for which to apply flow control on.
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* @throws Http2Exception if any protocol-related error occurred.
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*/
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void channelHandlerContext(ChannelHandlerContext ctx) throws Http2Exception;
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/**
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* Sets the connection-wide initial flow control window and updates all stream windows (but not the connection
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* stream window) by the delta.
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* <p>
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* Represents the value for
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* <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_INITIAL_WINDOW_SIZE</a>. This method should
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* only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
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*
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* @param newWindowSize the new initial window size.
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* @throws Http2Exception thrown if any protocol-related error occurred.
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*/
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void initialWindowSize(int newWindowSize) throws Http2Exception;
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/**
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* Gets the connection-wide initial flow control window size that is used as the basis for new stream flow
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* control windows.
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* <p>
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* Represents the value for
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* <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_INITIAL_WINDOW_SIZE</a>. The initial value
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* returned by this method must be {@link Http2CodecUtil#DEFAULT_WINDOW_SIZE}.
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*/
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int initialWindowSize();
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/**
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* Get the portion of the flow control window for the given stream that is currently available for sending/receiving
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* frames which are subject to flow control. This quantity is measured in number of bytes.
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*/
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int windowSize(Http2Stream stream);
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/**
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* Increments the size of the stream's flow control window by the given delta.
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* <p>
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* In the case of a {@link Http2RemoteFlowController} this is called upon receipt of a
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* {@code WINDOW_UPDATE} frame from the remote endpoint to mirror the changes to the window
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* size.
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* <p>
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* For a {@link Http2LocalFlowController} this can be called to request the expansion of the
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* window size published by this endpoint. It is up to the implementation, however, as to when a
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* {@code WINDOW_UPDATE} is actually sent.
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*
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* @param stream The subject stream. Use {@link Http2Connection#connectionStream()} for
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* requesting the size of the connection window.
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* @param delta the change in size of the flow control window.
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* @throws Http2Exception thrown if a protocol-related error occurred.
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*/
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void incrementWindowSize(Http2Stream stream, int delta) throws Http2Exception;
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}
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