Each stream node now includes incoming frames queue and sent/received counters
for tracking offset. The sent counter is not used, c->sent is used, not like
in crypto buffers, which have no connections.
If offset in CRYPTO frame doesn't match expected, following actions are taken:
a) Duplicate frames or frames within [0...current offset] are ignored
b) New data from intersecting ranges (starts before current_offset, ends
after) is consumed
c) "Future" frames are stored in a sorted queue (min offset .. max offset)
Once a frame is consumed, current offset is updated and the queue is inspected:
we iterate the queue until the gap is found and act as described
above for each frame.
The amount of data in buffered frames is limited by corresponding macro.
The CRYPTO and STREAM frame structures are now compatible: they share
the same set of initial fields. This allows to have code that deals with
both of this frames.
The ordering layer now processes the frame with offset and invokes the
handler when it can organise an ordered stream of data.
Quote: Conceptually, a packet number space is the context in which a packet
can be processed and acknowledged.
ngx_quic_namespace_t => ngx_quic_send_ctx_t
qc->ns => qc->send_ctx
ns->largest => send_ctx->largest_ack
The ngx_quic_ns(level) macro now returns pointer, not just index:
ngx_quic_get_send_ctx(c->quic, level)
ngx_quic_retransmit_ns() => ngx_quic_retransmit()
ngx_quic_output_ns() => ngx_quic_output_frames()
The request processing is delayed by a timer. Since nginx updates
internal time once at the start of each event loop iteration, this
normally ensures constant time delay, adding a mitigation from
time-based attacks.
A notable exception to this is the case when there are no additional
events before the timer expires. To ensure constant-time processing
in this case as well, we trigger an additional event loop iteration
by posting a dummy event for the next event loop iteration.
The offset in client CRYPTO frames is tracked in c->quic->crypto_offset_in.
This means that CRYPTO frames with non-zero offset are now accepted making
possible to finish handshake with client certificates that exceed max packet
size (if no reordering happens).
The c->quic->crypto_offset field is renamed to crypto_offset_out to avoid
confusion with tracking of incoming CRYPTO stream.
+ since number of ranges in unknown, provide a function to parse them once
again in handler to avoid memory allocation
+ ack handler now processes all ranges, not only the first
+ ECN counters are parsed and saved into frame if present
Such frames are grouped together in a switch and just ignored, instead of
closing the connection This may improve test coverage. All such frames
require acknowledgment.
The qc->closing flag is set when a connection close is initiated for the first
time.
No timers will be set if the flag is active.
TODO: this is a temporary solution to avoid running timer handlers after
connection (and it's pool) was destroyed. It looks like currently we have
no clear policy of connection closing in regard to timers.
Found with a previously received Initial packet with ACK only, which
instantiates a new connection but do not produce the handshake keys.
This can be triggered by a fairly well behaving client, if the server
stands behind a load balancer that stripped Initial packets exchange.
Found by F5 test suite.
This makes sending large number of bidirectional stream work within ngtcp2,
which doesn't bother sending optional STREAMS_BLOCKED when exhausted.
This also introduces tracking currently opened and maximum allowed streams.
Currently, the output is called periodically, each 200 ms to invoke
ngx_quic_output() that will push all pending frames into packets.
TODO: implement flags a-là Nagle & co (NO_DELAY/NO_PUSH...)
All frames collected to packet are moved into a per-namespace send queue.
QUIC connection has a timer which fires on the closest max_ack_delay time.
The frame is deleted from the queue when a corresponding packet is acknowledged.
The NGX_QUIC_MAX_RETRANSMISSION is a timeout that defines maximum length
of retransmission of a frame.
The quic->keys[4] array now contains secrets related to the corresponding
encryption level. All protection-level functions get proper keys and do
not need to switch manually between levels.
If early data is accepted, SSL_do_handshake() completes as soon as ClientHello
is processed. SSL_in_init() will report the handshake is still in progress.
Static buffers are used instead in functions where decryption takes place.
The pkt->plaintext points to the beginning of a static buffer.
The pkt->payload.data points to decrypted data actual start.
