This, uh, grew into something far bigger than expected, but it turns out, all of it was needed to eventually support this correctly.
- Adds configuration to client and server to set [SETTINGS_MAX_HEADER_LIST_SIZE](http://httpwg.org/specs/rfc7540.html#SETTINGS_MAX_HEADER_LIST_SIZE)
- If not set, a "sane default" of 16 MB is used (taken from golang's http2)
- Decoding header blocks now happens as they are received, instead of buffering up possibly forever until the last continuation frame is parsed.
- As each field is decoded, it's undecoded size is added to the total. Whenever a header block goes over the maximum size, the `frame` will be marked as such.
- Whenever a header block is deemed over max limit, decoding will still continue, but new fields will not be appended to `HeaderMap`. This is also can save wasted hashing.
- To protect against enormous string literals, such that they span multiple continuation frames, a check is made that the combined encoded bytes is less than the max allowed size. While technically not exactly what the spec suggests (counting decoded size instead), this should hopefully only happen when someone is indeed malicious. If found, a `GOAWAY` of `COMPRESSION_ERROR` is sent, and the connection shut down.
- After an oversize header block frame is finished decoding, the streams state machine will notice it is oversize, and handle that.
- If the local peer is a server, a 431 response is sent, as suggested by the spec.
- A `REFUSED_STREAM` reset is sent, since we cannot actually give the stream to the user.
- In order to be able to send both the 431 headers frame, and a reset frame afterwards, the scheduled `Canceled` machinery was made more general to a `Scheduled(Reason)` state instead.
Closes#18Closes#191
* Change send_reset to take &mut self.
While calling this function is the last thing that should be done with
the instance, the intent of the h2 library is not to be used directly by
users, but to be used as an implementation detail by other libraries.
Requiring `self` on `send_reset` is pretty annoying when calling the
function from inside a `Future` implementation. Also, all the other fns
on the type take `&mut self`.
* Remove the P: Peer generic from internals
* Split out `Respond` from `server::Stream`
This new type is used to send HTTP responses to the client as well as
reserve streams for push promises.
* Remove unused `Send` helper.
This could be brought back later when the API becomes stable.
* Unite `client` and `server` types
* Remove `B` generic from internal proto structs
This is a first step in removing the `B` generic from public API types
that do not strictly require it.
Currently, all public API types must be generic over `B` even if they do
not actually interact with the send data frame type. The first step in
removing this is to remove `B` as a generic on all internal types.
* Remove `Buffer<B>` from inner stream state
This is the next step in removing the `B` generic from all public API
types. The send buffer is the only type that requires `B`. It has now
been extracted from the rest of the stream state.
The strategy used in this PR requires an additional `Arc` and `Mutex`,
but this is not a fundamental requirement. The additional overhead can
be avoided with a little bit of unsafe code. However, this optimization
should not be made until it is proven that it is required.
* Remove `B` generic from `Body` + `ReleaseCapacity`
This commit actually removes the generic from these two public API
types. Also note, that removing the generic requires that `B: 'static`.
This is because there is no more generic on `Body` and `ReleaseCapacity`
and the compiler must be able to ensure that `B` outlives all `Body` and
`ReleaseCapacity` handles.
In practice, in an async world, passing a non 'static `B` is never going
to happen.
* Remove generic from `ResponseFuture`
This change also makes generic free types `Send`. The original strategy
of using a trait object meant that those handles could not be `Send`.
The solution was to avoid using the send buffer when canceling a stream.
This is done by transitioning the stream state to `Canceled`, a new
`Cause` variant.
* Simplify Send::send_reset
Now that implicit cancelation goes through a separate path, the
send_reset function can be simplified.
* Export types common to client & server at root
* Rename Stream -> SendStream, Body -> RecvStream
* Implement send_reset on server::Respond
Alter frame::Reason to a struct with a single u32 member.
Introduce Constants to the impl for existing Reasons. Change all usage
in the library and its tests to adopt this change,
using the new constants.
The Connection type is a `Future` that drives all of the IO of the
client connection.
The Client type is separate, and is used to send requests into the
connection.
Both Recv::open and Rev::recv_headers check new stream ids against the
previously stream id. The second such check fails.
Now, only Recv::open performs stream id checks.
Fixes#110
This change adds a .rustfmt.toml that includes ALL supported settings,
12 of which we have overridden to attempt to cater to our own
proclivities.
rustfmt is checked in the rust-nightly CI job.
This patch does a bunch of refactoring, mostly around error types, but it also
paves the way to allow `Codec` to be used standalone.
* `Codec` (and `FramedRead` / `FramedWrite`) is broken out into a codec module.
* An h2-codec crate is created that re-exports the frame and codec modules.
* New error types are introduced in the internals:
* `RecvError` represents errors caused by trying to receive a frame.
* `SendError` represents errors caused by trying to send a frame.
* `UserError` is an enum of potential errors caused by invalid usage
by the user of the lib.
* `ProtoError` is either a `Reason` or an `io::Error`. However it doesn't
specify connection or stream level.
* `h2::Error` is an opaque error type and is the only error type exposed
by the public API (used to be `ConnectionError`).
There are misc code changes to enable this as well. The biggest is a new "sink"
API for `Codec`. It provides buffer which queues up a frame followed by flush
which writes everything that is queued. This departs from the `Sink` trait in
order to provide more accurate error values. For example, buffer can never fail
(but it will panic if `poll_ready` is not called first).
Malformed requests and responses should immediately result in a
RST_STREAM. To support this, received header frames are validated and
converted to Request / Response values immediately on receipt and before
buffering.
Restructure send flow control such that sending data is always accepted by `Stream`. Data frames will be buffered until there is available window to send them. Producers can monitor the available window capacity to decide if data should be produced.
