Motivation:
In a few classes, Netty starts a thread and then sets the context classloader of these threads
to prevent classloader leaks. The Thread#setContextClassLoader method is a privileged method in
that it requires permissions to be executed when there is a security manager in place. Unless
these calls are wrapped in a doPrivileged block, they will fail in an environment with a security
manager and restrictive policy in place.
Modifications:
Wrap the calls to Thread#setContextClassLoader in a AccessController#doPrivileged block.
Result:
After this change, the threads can set the context classloader without any errors in an
environment with a security manager and restrictive policy in place.
Motivation:
Usages of HttpResponseStatus may result in more object allocation then necessary due to not looking for cached objects and the AsciiString parsing method not being used due to CharSequence method being used instead.
Modifications:
- HttpResponseDecoder should attempt to get the HttpResponseStatus from cache instead of allocating a new object
- HttpResponseStatus#parseLine(CharSequence) should check if the type is AsciiString and redirect to the AsciiString parsing method which may not require an additional toString call
- HttpResponseStatus#parseLine(AsciiString) can be optimized and doesn't require and may not require object allocation
Result:
Less allocations when dealing with HttpResponseStatus.
Motivation:
When we cancel the flowcontrolled writes we did create a new StreamException for each write that was enqueued. Creating Exceptions is very expensive due of filling the stacktrace.
Modifications:
Only create the StreamException once and reuse the same for all the flowcontrolled writes (per stream).
Result:
Less expensive to cancel flowcontrolled writes.
Motiviation:
DefaultChannelPipeline and AbstractChannelHandlerContext maintain state
which indicates if a ChannelHandler should be invoked or not. However
the state is updated to allow the handler to be invoked only after the
handlerAdded method completes. If the handlerAdded method generates
events which may result in other methods being invoked on that handler
they will be missed.
Modifications:
- DefaultChannelPipeline should set the state before calling
handlerAdded
Result:
DefaultChannelPipeline will allow events to be processed during the
handlerAdded process.
Motivation:
When decoding stomp frames a lot of unnecessary character arrays are created when parsing headers.
For every header, an array is created to read the line into and then more when splitting the line at the colon.
Modifications:
Parse key and value of a header while reading the line instead of afterwards.
Reuse a single AppendableCharSequence.
Reduce initial size of AppendableCharSequence when reading the command as it is expected to be short.
Result:
Allocations when parsing stomp frames have dropped significantly.
Motivation:
We used Recycler for the CodecOutputList which is not optimized for the use-case of access only from the same Thread all the time.
Modifications:
- Use FastThreadLocal for CodecOutputList
- Add benchmark
Result:
Less overhead in our codecs.
Motivation:
The usage of DnsCache in DnsNameResolver was racy in general. First of the isEmpty() was not called in a synchronized block while we depended on synchronized. The other problem was that this whole synchronization only worked if the DefaultDnsCache was used and the returned List was not wrapped by the user.
Modifications:
- Rewrite DefaultDnsCache to not depend on synchronization on the returned List by using a CoW approach.
Result:
Fixes [#7583] and other races.
Motivation:
Http2FrameCodec increases the initialWindowSize when the user attempts to increase the connection flow control window. The initialWindowSize should only be touched as a result of a SETTINGS frame, and otherwise may result in flow control getting out of sync with our peer.
Modifications:
- Http2FrameCodec shouldn't update the initialWindowSize when a WindowUpdateFrame is written on the connection channel
Result:
More correct WindowUpdate processing.
Motivation:
It would be good to provide a docker image for people that want to build netty on linux.
Modifications:
Add a docker file
Result:
People can more easily build netty. Fixes [#7585].
Motivation:
Depending on the implementation of ByteBuf nioBuffer(...) and nioBuffers(...) may either share the content or return a ByteBuffer that contains a copy of the content.
Modifications:
Fix javadocs.
Result:
Correct docs.
Motivation:
Calling ByteBuf.toString(Charset) on the same buffer from multiple threads at the same time produces unexpected results, such as various exceptions and/or corrupted output. This is because ByteBufUtil.decodeString(...) is taking the source ByteBuffer for CharsetDecoder.decode() from ByteBuf.internalNioBuffer(int, int), which is not thread-safe.
Modification:
Call ByteBuf.nioBuffer() instead of ByteBuf.internalNioBuffer() to get the source buffer to pass to CharsetDecoder.decode().
Result:
Fixes the possible race condition.
Motivation:
ObjectCleaner inovkes a Runnable which may execute user code (FastThreadLocal#onRemoval) and therefore exceptions maybe thrown. If an exception is thrown the cleanup thread will exit prematurely and we may never finish cleaning up which will result in leaks.
Modifications:
- ObjectCleaner should suppress exceptions and continue cleaning
Result:
ObjectCleaner will reliably clean despite exceptions being thrown.
Motivation:
ObjectCleaner polls a ReferenceQueue which will block indefinitely. However it is possible there is a race condition between the live set of objects being empty due to the WeakReference being cleaned/cleared and polling the queue. If this situation occurs the cleanup thread may never unblock if no more objects are added to the live set, and may result in an application's failure to gracefully close.
Modifications:
- ReferenceQueue.remove should use a timeout to compensate for the race condition, and avoid dead lock
Result:
No more dead lock in ObjectCleaner when polling the ReferenceQueue.
Motivation:
HPackDecoder works on entire header block, we shouldn't encounter
incomplete header fields. If we do we should treat it as
a decoding error and according to the specification:
A decoding error in a header block MUST be treated as
a connection error (Section 5.4.1) of type COMPRESSION_ERROR.
Modifications:
* Check final state in HpackDecoder once we've decoded all the data.
Result:
* Throw a connection error if we receive incomplete header fields
* H2spec 4.3 tests all passes
Motivation:
We should fail fast when DefaultChannelPromise is constructed with null as Channel as otherwise it will fail with a NPE once we call setSuccess / setFailure.
Modifications:
Add null check and test.
Result:
Fail fast.
Motivation:
Will allow easy removal of deprecated methods in future.
Modification:
Replaced ctx.attr(), ctx.hasAttr() with ctx.channel().attr(), ctx.channel().hasAttr().
Result:
No deprecated ctx.attr(), ctx.hasAttr() methods usage.
Motivation:
According to RFC 1952, concatenation of valid gzip streams is also a valid gzip stream. JdkZlibDecoder only processed the first and discarded the rest.
Modifications:
- Introduced a constructor argument decompressConcatenated that if true, JdkZlibDecoder would continue to process the stream.
Result:
- If 'decompressConcatenated = true', concatenated streams would be processed in
compliance to RFC 1952.
- If 'decompressConcatenated = false' (default), existing behavior would remain.
Motivation:
We need to ensure we only call List.* methods in the synchronized block as the returned List may not be thread-safe.
Modifications:
Do not call isEmpty() outside of the synchronized block.
Result:
Fixes [#7583]
Motivation:
We did not correctly take the position into account when wrapping a ByteBuffer via ReadOnlyUnsafeDirectByteBuf as we obtained the memory address from the original ByteBuffer and not the slice we take.
Modifications:
- Correctly use the slice to obtain memory address.
- Add test case.
Result:
Fixes [#7565].
Motivation:
We recently removed support for renegotiation, but there are still some hooks to attempt to allow remote initiated renegotiation to succeed. The remote initated renegotiation can be even more problematic from a security stand point and should also be removed.
Modifications:
- Remove state related to remote iniated renegotiation from OpenSslEngine
Result:
More renegotiation code removed from the OpenSslEngine code path.
Motivation:
Http2FrameStream#CONNECTION_STREAM is required to identify the
connection stream. However this leads to inconsistent usage from a user
perspective. When a user creates a Http2Frame for a non-connection
stream, the Http2MultiplexCodec automatically sets the stream, and the
user is never exposed to the Http2FrameStream object. However when the
user writes a Http2Frame for a connection stream they are required to
set the Http2FrameStream object. We can remove the Http2FrameStream#CONNECTION_STREAM
and keep the Http2FrameStream object internal, and therefore consistent
between the connection and non-connection use cases.
Modifications:
- Remove Http2FrameStream#CONNECTION_STREAM
- Update Http2FrameCodec to handle Http2Frame#stream() which returns
null
Result:
More consistent usage on http2 parent channel and http2 child channel.
Motivation:
IovArray implements MessageProcessor, and the processMessage method will continue to be called during iteration until it returns true. A recent commit b215794de3 changed the return value to only return true if any component of a CompositeByteBuf was added as a result of the method call. However this results in the iteration continuing, and potentially subsequent smaller buffers maybe added, which will result in out of order writes and generally corrupts data.
Modifications:
- IovArray#add should return false so that the MessageProcessor#processMessage will stop iterating.
Result:
Native transports which use IovArray will not corrupt data during gathering writes of CompositeByteBuf objects.
Motivation:
When using netty on android or with for example a IBM JVM it may not be able to build a SslContext as we hardcoded the use of JKS and SunX509 (which both may not be present).
Modifications:
- Use the default algorithm / type which can be override via a System property
- Remove System property check as its redundant with KeyManagerFactory.getDefaultAlgorithm()
Result:
More portable code. Fixes [#7546].
Motivation:
DnsNameResolverTest has not been updated in a while.
Modifications:
- Update the DOMAINS definition in DnsNameResolverTest
Result:
More current domain names.
Motivation:
SSL.setState() has gone from openssl 1.1. Calling it is, and probably
always has been, incorrect. Doing renogitation in this manner is
potentially insecure. There have been at least two insecure
renegotiation vulnerabilities in users of the OpenSSL library.
Renegotiation is not necessary for correct operation of the TLS protocol.
BoringSSL has already eliminated this functionality, and the tests
(now deleted) were not running on BoringSSL.
Modifications:
If the connection setup has completed, always return that
negotiation is not supported. Previously this was done only if we were
the client.
Remove the tests for this functionality.
Fixes#6320.
Motivation:
DefaultHttpDataFactory uses HttpRequest as map keys.
Because of the implementation of "hashCode"" and "equals" in DefaultHttpRequest,
if we use normal maps, HttpDatas of different requests may end up in the same map entry,
causing cleanup bug.
Consider this example:
- Suppose that request1 is equal to request2, causing their HttpDatas to be stored in one single map entry.
- request1 is cleaned up first, while request2 is still being decoded.
- Consequently request2's HttpDatas are suddenly gone, causing NPE, or worse loss of data.
This bug can be reproduced by starting the HttpUploadServer example,
then run this command:
ab -T 'application/x-www-form-urlencoded' -n 100 -c 5 -p post.txt http://localhost:8080/form
post.txt file content:
a=1&b=2
There will be errors like this:
java.lang.NullPointerException
at io.netty.handler.codec.http.multipart.MemoryAttribute.getValue(MemoryAttribute.java:64)
at io.netty.handler.codec.http.multipart.MixedAttribute.getValue(MixedAttribute.java:243)
at io.netty.example.http.upload.HttpUploadServerHandler.writeHttpData(HttpUploadServerHandler.java:271)
at io.netty.example.http.upload.HttpUploadServerHandler.readHttpDataChunkByChunk(HttpUploadServerHandler.java:230)
at io.netty.example.http.upload.HttpUploadServerHandler.channelRead0(HttpUploadServerHandler.java:193)
at io.netty.example.http.upload.HttpUploadServerHandler.channelRead0(HttpUploadServerHandler.java:66)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:310)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:284)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1412)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:943)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:141)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)
Modifications:
Keep identity of requests by using IdentityHashMap
Result:
DefaultHttpDataFactory is fixed.
The ConcurrentHashMap is replaced with a synchronized map, but I think the performance won't be affected much in real web apps.
Motivation:
At the moment we use netty.io as BAD_HOST with an port that we know is timing out. This may change in the future so we should better use 198.51.100.254 which is specified as "for documentation only".
Modifications:
Replace netty.io with 198.51.100.254 in tests that depend on BAD_HOST.
Result:
More future proof code.
Motivation:
Http2FrameCodecTest#newOutboundStream has a timeout of 1 second and has been observed to timeout on CI servers.
Modifications:
- Increase the timeout to 5 seconds
Result:
Less false positive test failures on CI servers.
Motivation:
Our tests are often asynchronous and have timeouts to avoid hanging indefinitely. However sometimes the timeouts maybe set to low for the CI servers. It would be helpful to confirm if the application was busy with GC and if that was a contributing factor to the test timing out.
Modifications:
- Unit tests should run with -XX:+PrintGCDetails by default
Result:
More visibility into GC behavior in unit tests.
Motivation:
FastThreadLocal#set calls isIndexedVariableSet to determine if we need to register with the cleaner, but the set(InternalThreadLocalMap, V) method will also internally do this check so we can share code and only do the check a single time.
Modifications:
- extract code from set(InternalThreadLocalMap, V) so it can be called externally to determine if a new item was created
Result:
Less code duplication in FastThreadLocal#set.
Motivation:
HpackDecoder#addHeader takes in the streamId as a parameter but no longer uses it.
Modifications:
- Remove the streamId parameter from HpackDecoder#addHeader
Result:
Less unused parameters in HpackDecoder.
Motivation:
e329ca1 introduced the user of ObjectCleaner in FastThreadLocal but we missed the case to register our cleaner task if FastThreadLocal.set was called only.
Modifications:
- Use ObjectCleaner also when FastThreadLocal.set is used.
- Add test case.
Result:
ObjectCleaner is always used.
Motivation:
According to the HTTP/2 Spec:
SETTINGS_MAX_HEADER_LIST_SIZE (0x6): This advisory setting informs a
peer of the maximum size of header list that the sender is
prepared to accept, in octets. The value is based on the
uncompressed size of header fields, including the length of the
name and value in octets plus an overhead of 32 octets for each
header field.
We were accounting for the 32 bytes when encoding in HpackEncoder,
but not when decoding in HPackDecoder.
Modifications:
- Add 32 bytes to the header list length for each entry when decoding
with HPackDecoder.
Result:
- We account for the 32 bytes overhead by header entry in HPackDecoder
Motivation:
Allow pre-computing calculation of the constants for compiler where it could be.
Similar fix in OpenJDK: [1].
Modifications:
- Use parentheses.
- Simplify static initialization of `BYTE2HEX_*` arrays in `StringUtil`.
Result:
Less bytecode, possible faster calculations at runtime.
[1] https://bugs.openjdk.java.net/browse/JDK-4477961
Motivation:
There is no guarantee that FastThreadLocal.onRemoval(...) is called if the FastThreadLocal is used by "non" FastThreacLocalThreads. This can lead to all sort of problems, like for example memory leaks as direct memory is not correctly cleaned up etc.
Beside this we use ThreadDeathWatcher to check if we need to release buffers back to the pool when thread local caches are collected. In the past ThreadDeathWatcher was used which will need to "wakeup" every second to check if the registered Threads are still alive. If we can ensure FastThreadLocal.onRemoval(...) is called we do not need this anymore.
Modifications:
- Introduce ObjectCleaner and use it to ensure FastThreadLocal.onRemoval(...) is always called when a Thread is collected.
- Deprecate ThreadDeathWatcher
- Add unit tests.
Result:
Consistent way of cleanup FastThreadLocals when a Thread is collected.
Motiviation:
In our replace(...) methods we always used validation for the newly created headers while the original headers may not use validation at all.
Modifications:
- Only use validation if the original headers used validation as well.
- Ensure we create a copy of the headers in replace(...).
Result:
Fixes [#5226]
Motivation:
Currently the remote flow controller limits the maximum amount of pending data to Integer.MAX_VALUE. The overflow handling is also not very graceful in that it may lead to infinite loops, or otherwise no progress being made.
Modifications:
- StreamByteDistributor and RemoteFlowController should support pending bytes of type long.
Result:
Fixes https://github.com/netty/netty/issues/4283
Motivation:
As shown in issues it is sometimes hard to understand why a leak was reported when the user just calles EmbeddedChannel.readInbound() / EmbeddedChannel.readOutbound() and drop the message on the floor.
Modifications:
Add a hint before handover the message to the user and transfer the ownership.
Result:
Easier debugging of leaks caused by EmbeddedChannel.read*().
Motivation:
The JMH doc suggests to use BlackHoles to avoid dead code elimination hence would be better to follow this best practice.
Modifications:
Each benchmark method is returning the ByteBuf/ByteBuffer to avoid the JVM to perform any dead code elimination.
Result:
The results are more reliable and comparable to the others provided by other ByteBuf benchmarks (eg HeapByteBufBenchmark)
Motivation:
http/2 counts header sizes somewhat inconsistently. Sometimes, headers
which are substantively less than the header list size will be measured
as longer than the header list size.
Modifications:
Keep better track of the nameLength of a given name, so that we don't
accidentally end up reusing a nameLength.
Result:
More consistent measurement of header list size.
Fixes#7511.
Motivation :
Avoid unnecessary array allocation when using the function with varargs in the DefaultChannelPipeline class.
Modifications :
Added addLast and addFirst overloaded methods with 1 handler instead of varargs.
Result :
No array allocation when using simple construction like pipeline.addLast(new Handler());
Motivation:
H2Spec is a conformance testing tool for HTTP/2 implementation.
To help us fix failing tests and avoid future regression we
should run h2spec as part of the build
Modifications:
- Add testsuite-http2 module to the project
Result:
- Run h2spec as part of the build
- 22 tests are currently ignored, we should remove the ignore as we fix them
Motivation:
We should remove the WeakOrderedQueue from the WeakHashMap directly if possible and only depend on the semantics of the WeakHashMap if there is no other way for us to cleanup it.
Modifications:
Override onRemoval(...) to remove the WeakOrderedQueue if possible.
Result:
Less overhead and quicker collection of WeakOrderedQueue for some cases.
Motivation
There is currently no way to enforce the position of a handler in a ChannelPipeline and assume you wanted to write something like a custom Channel type that acts as a proxy between two other Channels.
ProxyChannel(Channel client, Channel server) {
client calls write(msg) -> server.write(msg)
client calls flush() -> server.flush()
server calls fireChannelRead(msg) -> client.write(msg)
server calls fireChannelReadComplete() -> client.flush()
}
In order to make it work reliably one needs to be able to scoop up the various events at the head and tail of the pipeline. The head side of the pipeline is covered by Unsafe and it's also relatively safe to count on the user to not use the addFirst() method to manipulate the pipeline. The tail side is always at a risk of getting broken because addLast() is the goto method to add handlers.
Modifications
Adding a few extra methods to DefaultChannelPipeline that expose some of the events that reach the pipeline's TailContext.
Result
Fixes#7484
