[openssl/openssl] e718b2: Correctly track the original length when generatin...

[Matt Caswell]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: e718b248f94fa41562b740482813716a2ff13db5
      https://github.com/openssl/openssl/commit/e718b248f94fa41562b740482813716a2ff13db5
  Author: Matt Caswell <matt at openssl.org>
  Date:   2023-11-06 (Mon, 06 Nov 2023)

  Changed paths:
    M ssl/quic/quic_txp.c

  Log Message:
  -----------
  Correctly track the original length when generating a stream frame

txp_generate_stream_frames() plans chunks of data to send via the
function txp_plan_stream_chunk(). That function may clamp the amount in
the chunk due to flow control, even though there is more available to send.

We should take this into account when deciding whether or not to try
serializing the next chunk.

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22601)