Summary:
On loss timer, currently we knock all handshake packets out of the OP
list and resend everything. This means miss RTT sampling opportunities during
handshake if loss timer fires, and given our initial loss timer is likely not a
good fit for many networks, it probably fires a lot.
This diff keeps handshake packets in the OP list, and add packet cloning
support to handshake packets so we can clone them and send as probes.
With this, the handshake alarm is finally removed. PTO will take care of all
packet number space.
The diff also fixes a bug in the CloningScheduler where we missed cipher
overhead setting. That broke a few unit tests once we started to clone
handshake packets.
The writeProbingDataToSocket API is also changed to support passing a token to
it so when we clone Initial, token is added correctly. This is because during
packet cloning, we only clone frames. Headers are fresh built.
The diff also changed the cloning behavior when there is only one outstanding
packet. Currently we clone it twice and send two packets. There is no point of
doing that. Now when loss timer fires and when there is only one outstanding
packet, we only clone once.
The PacketEvent, which was an alias of PacketNumber, is now a real type that
has both PacketNumber and PacketNumberSpace to support cloning of handshake
packets. I think in the long term we should refactor PacketNumber itself into a
real type.
Reviewed By: mjoras
Differential Revision: D19863693
fbshipit-source-id: e427bb392021445a9388c15e7ea807852ddcbd08
Summary:
Becuase when we clone an existing packet, the logic inside the current
writetStreamFrameHeader is no longer correct.
Reviewed By: mjoras
Differential Revision: D21383828
fbshipit-source-id: 8e6bbb048eefd97ca7cf17b89edc2f395f274a73
Summary:
Other frames have been using the BufQueue version of frame writing.
Change this for Crypto streams as well
Reviewed By: mjoras
Differential Revision: D20947921
fbshipit-source-id: 1cfa0f3806e8d74e8c8a4864498e1c06b55d5292
Summary: use the BufQueue version of writeStreamFrameData for retransmission.
Reviewed By: mjoras
Differential Revision: D20920391
fbshipit-source-id: 5fe7017329f801e0ac5428257b9a61000e26e203
Summary:
As it turns out, the extra indirection from storing a unique_ptr is not worse than the gain from using an `F14ValueMap` versus an `F14VectorMap`.
This reduces the `find` cost measurably in profiles, and doesn't appear to have any real negative effects otherwise.
Reviewed By: yangchi
Differential Revision: D20923854
fbshipit-source-id: a75c4649ea3dbf0e6c89ebfe0d31d082bbdc31fd
Summary:
Previously we stored an `IntervalSet` in each `WriteAckFrame`. We don't need to do this, as by the time we are writing an `ACK` the `IntervalSet` is complete. Instead of bothering with the `IntervalSet` operations, we can simply serialize it to a reverse-sorted `vector.`
Additionally this has some micro-optimizations for filling the ACK frame, with a new function for getting varint size.
Reviewed By: yangchi
Differential Revision: D19397728
fbshipit-source-id: ba6958fb36a4681edaa8394b1bcbbec3472e177d
Summary:
The retransmission buffer tracks stream frame data we have sent that is currently unacked. We keep this as a sorted `deque`. This isn't so bad for performance, but we can do better if we break ourselves of the requirement that it be sorted (removing a binary search on ACK).
To do this we make the buffer a map of offset -> `StreamBuffer`.
There were two places that were dependent on the sorted nature of the list.
1. For partial reliablity we call `shrinkBuffers` to remove all unacked buffers less than an offset. For this we now have to do it with a full traversal of the retransmission buffer instead of only having to do an O(offset) search. In the future we could make this better by only lazily deleting from the retransmission buffer on ACK or packet loss.
2. We used the start of the retransmission buffer to determine if a delivery callback could be fired for a given offset. We need some new state to track this. Instead of tracking unacked buffers, we now track acked ranges using the existing `IntervalSet`. This set should be small for the typical case, as we think most ACKs will come in order and just cause existing ranges to merge.
Reviewed By: yangchi
Differential Revision: D18609467
fbshipit-source-id: 13cd2164352f1183362be9f675c1bdc686426698
Summary:
The function indeed compares a Stream frame to a buffer, not an Ack
frame to a buffer.
Reviewed By: sharma95
Differential Revision: D18000632
fbshipit-source-id: fbbc36378404f8f52a199114af48b9020d0569e8
Summary:
Use the custom variant type for write frames as well, now that
we use them for read frames.
Reviewed By: mjoras
Differential Revision: D17776862
fbshipit-source-id: 47093146d0f1565c22e5393ed012c70e2e23d279
Summary:
Make a custom variant type for PacketHeader. By not relying on boost::variant
this reduces the code size of the implementation.
This uses a combination of a union type as well as a enum type to emulate a variant
Reviewed By: yangchi
Differential Revision: D17187589
fbshipit-source-id: 00c2b9b8dd3f3e73af766d84888b13b9d867165a
Summary:
Prior to this diff we would clone out an entire flow control's worth of data from the writebuffer and then clone out a smaller portion of that to write into the packet builder. This is extremely wasteful when we have a large flow control window.
Additionally we would always write the stream data length field even when we are going to fill the remainder of the packet with the current stream frame. By first calculating the amount of data that needs to can be written and writing the header, we can now omit the data length field when we can fill the whole packet.
Reviewed By: yangchi
Differential Revision: D15769514
fbshipit-source-id: 95ac74eebcde87dd06de54405d7f69c42362e29c
Summary:
With partial reliability we adjust retransmission queue on skips; we need to account for that when we match buffers in retransmission queue.
In fully reliable mode an ack frame must always match a single buffer from re-tranmission queue (offset, length and eom).
In partially reliable mode we can run into two more scenarios in addition to the above:
* re-transmisison buffer for which the ack frame arrived has been removed fully
* re-transmisison buffer for which the ack frame arrived has been removed partially
If full buffer is missing - ignore the ack.
If part of the buffer is missing, make sure that the adjusted offset and length match to that found in the ack frame.
Reviewed By: yangchi
Differential Revision: D15301304
fbshipit-source-id: f281fa30957c1c13c42c05684984f9a1acaa4e34
Summary:
There is a race condition with min data frame (skip) and ack frame when it comes to retransmission buffer.
Sometimes, we receive both min data and ack frames, the min data frame gets processed first and it clears out retransmission buffer (expected), but then we get to process the ack frame and there is that CHECK that expects the retransmission buffer to have at least one unacked buffer in it - there is none and then the app crashes.
Reviewed By: siyengar
Differential Revision: D14908630
fbshipit-source-id: d8bcd70291e1fd3618065fdeb44bedc6ac66bcaa
