Each frame type used in quic_frame union has been renamed with the
following prefix "qf_". This helps to differentiate frame instances from
other internal objects.
This should be backported up to 2.7.
When a STREAM frame is re-emitted, it will point to the same stream
buffer as the original one. If an ACK is received for either one of
these frame, the underlying buffer may be freed. Thus, if the second
frame is declared as lost and schedule for retransmission, we must
ensure that the underlying buffer is still allocated or interrupt the
retransmission.
Stream buffer is stored as an eb_tree indexed by the stream ID. To avoid
to lookup over a tree each time a STREAM frame is re-emitted, a lost
STREAM frame is flagged as QUIC_FL_TX_FRAME_LOST.
In most cases, this code is functional. However, there is several
potential issues which may cause a segfault :
- when explicitely probing with a STREAM frame, the frame won't be
flagged as lost
- when splitting a STREAM frame during retransmission, the flag is not
copied
To fix both these cases, QUIC_FL_TX_FRAME_LOST flag has been converted
to a <dup> field in quic_stream structure. This field is now properly
copied when splitting a STREAM frame. Also, as this is now an inner
quic_frame field, it will be copied automatically on qc_frm_dup()
invocation thus ensuring that it will be set on probing.
This issue was encounted randomly with the following backtrace :
#0 __memmove_avx512_unaligned_erms ()
#1 0x000055f4d5a48c01 in memcpy (__len=18446698486215405173, __src=<optimized out>,
#2 quic_build_stream_frame (buf=0x7f6ac3fcb400, end=<optimized out>, frm=0x7f6a00556620,
#3 0x000055f4d5a4a147 in qc_build_frm (buf=buf@entry=0x7f6ac3fcb5d8,
#4 0x000055f4d5a23300 in qc_do_build_pkt (pos=<optimized out>, end=<optimized out>,
#5 0x000055f4d5a25976 in qc_build_pkt (pos=0x7f6ac3fcba10,
#6 0x000055f4d5a30c7e in qc_prep_app_pkts (frms=0x7f6a0032bc50, buf=0x7f6a0032bf30,
#7 qc_send_app_pkts (qc=0x7f6a0032b310, frms=0x7f6a0032bc50) at src/quic_conn.c:4184
#8 0x000055f4d5a35f42 in quic_conn_app_io_cb (t=0x7f6a0009c660, context=0x7f6a0032b310,
This should fix github issue #2051.
This should be backported up to 2.6.
Add a <loss_count> new field in quic_frame structure. This field is set
to 0 and incremented each time a sent packet is declared lost. If
<loss_count> reached a hard-coded limit, the connection is deemed as
failing and is closed immediately with a CONNECTION_CLOSE using
INTERNAL_ERROR.
By default, limit is set to 10. This should ensure that overall memory
usage is limited if a peer behaves incorrectly.
This should be backported up to 2.7.
Define two utility functions for quic_frame allocation :
* qc_frm_alloc() is used to allocate a new frame
* qc_frm_dup() is used to allocate a new frame by duplicating an
existing one
Theses functions are useful to centralize quic_frame initialization.
Note that pool_zalloc() is replaced by a proper pool_alloc() + explicit
initialization code.
This commit will simplify implementation of the per frame retransmission
limitation. Indeed, a new counter will be added in quic_frame structure
which must be initialized to 0.
This should be backported up to 2.7.
A dedicated <fin> field was used in quic_stream structure. However, this
info is already encoded in the frame type field as specified by QUIC
protocol.
In fact, only code for packet reception used the <fin> field. On the
sending side, we only checked for the FIN bit. To align both sides,
remove the <fin> field and only used the FIN bit.
This should be backported up to 2.7.
Define a new structure quic_err to abstract a QUIC error type. This
allows to easily differentiate a transport and an application error
code. This simplifies error transmission from QUIC MUX and H3 layers.
This new type is defined in quic_frame module. It is used to replace
<err_code> field in <quic_conn>. QUIC_FL_CONN_APP_ALERT flag is removed
as it is now useless.
Utility functions are defined to be able to quickly instantiate
transport, tls and application errors.
quic_frame-t.h and xprt_quic-t.h include themselves mutually. This may
cause some troubles later.
In fact, xprt_quic does not need to include quic_frame so remove this.
And as quic_frame is a generic source file which is included in multiple
places, it is useful to also remove the xprt_quic include in it. Use
forward declaration for this.
A crash is possible under such circumtances:
- The congestion window is drastically reduced to its miniaml value
when a quic listener is experiencing extreme packet loss ;
- we enqueue several STREAM frames to be resent and some of them could not be
transmitted ;
- some of the still in flight are acknowledged and trigger the
stream memory releasing ;
- when we come back to send the remaing STREAM frames, haproxy
crashes when it tries to build them.
To fix this issue, we mark the STREAM frame as lost when detected as lost.
Then a lookup if performed for the stream the STREAM frames are attached
to before building them. They are released if the stream is no more available
or the data range of the frame is consumed.
We want to track the frames which have been duplicated during retransmissions so
that to avoid uselessly retransmitting frames which would already have been
acknowledged. ->origin new member is there to store the frame from which a copy
was done, ->reflist is a list to store the frames which are copies.
Also ensure all the frames are zeroed and that their ->reflist list member is
initialized.
Add QUIC_FL_TX_FRAME_ACKED flag definition to mark a TX frame as acknowledged.
Move the xprt-buf and ack related fields from qcs to the qc_stream_desc
structure. In exchange, qcs has a pointer to the low-level stream. For
each new qcs, a qc_stream_desc is automatically allocated.
This simplify the transport layer by removing qcs/mux manipulation
during ACK frame parsing. An additional check is done to not notify the
MUX on sending if the stream is already released : this case may now
happen on retransmission.
To complete this change, the quic_stream frame now references the
quic_stream instance instead of a qcs.
The TX packet refcounting had come with the multithreading support but not only.
It is very useful to ease the management of the memory allocated for TX packets
with TX frames attached to. At some locations of the code we have to move TX
frames from a packet to a new one during retranmission when the packet has been
deemed as lost or not. When deemed lost the memory allocated for the paquet must
be released contrary to when its frames are retransmitted when probing (PTO).
For now on, thanks to this patch we handle the TX packets memory this way. We
increment the packet refcount when:
- we insert it in its packet number space tree,
- we attache an ack-eliciting frame to it.
And reciprocally we decrement this refcount when:
- we remove an ack-eliciting frame from the packet,
- we delete the packet from its packet number space tree.
Note that an optimization WOULD NOT be to fully reuse (without releasing its
memorya TX packet to retransmit its contents (its ack-eliciting frames). Its
information (timestamp, in flight length) to be processed by packet loss detection
and the congestion control.
As reported by Tim in issue #1428, our sources are clean, there are
just a few files with a few rare non-ASCII chars for the paragraph
symbol, a few typos, or in Fred's name. Given that Fred already uses
the non-accentuated form at other places like on the public list,
let's uniformize all this and make sure the code displays equally
everywhere.
Simplify the data manipulation of STREAM frames on TX. Only stream data
and len field are used to generate a valid STREAM frames from the
buffer. Do not use the offset field, which required that a single buffer
instance should be shared for every frames on a single stream.
There is no need to use an MT_LIST to store frames to send from a packet
number space. This is a reminiscence for multi-threading support for the TX part.
Some applications may send some information about the reason why they decided
to close a connection. Add them to CONNECTION_CLOSE frame traces.
Take the opportunity of this patch to shorten some too long variable names
without any impact.
Set the HTX EOM flag on RX the app layer. This is required to notify
about the end of the request for the stream analyzers, else the request
channel never goes to MSG_DONE state.
Re-implement the QUIC mux. It will reuse the mechanics from the previous
mux without all untested/unsupported features. This should ease the
maintenance.
Note that a lot of features are broken for the moment. They will be
re-implemented on the following commits to have a clean commit history.
No need to include the full tree management code, type files only
need the definitions. Doing so reduces the whole code size by around
3.6% and the build time is down to just 6s.
The STREAM data to send coming from the upper layer must be stored until
having being acked by the peer. To do so, we store them in buffer structs,
one by stream (see qcs.tx.buf). Each time a STREAM is built by quic_push_frame(),
its offset must match the offset of the first byte added to the buffer (modulo
the size of the buffer) by the frame. As they are not always acknowledged in
order, they may be stored in eb_trees ordered by their offset to be sure
to sequentially delete the STREAM data from their buffer, in the order they
have been added to it.
These structures are similar. quic_tx_frm was there to try to reduce the
size of such objects which embed a union for all the QUIC frames.
Furtheremore this patch fixes the issue where quic_tx_frm objects were freed
from the pool for quic_frame.
This patch imports all the definitions for QUIC protocol with few modifications
from 20200720-quic branch of quic-dev repository found at
https://github.com/haproxytech/quic-dev.
