[PATCH v14 00/10] net: tcp: improve tcp support in legacy stack

[Mikhail Kshevetskiy]

Legacy TCP stack is bad. Here are some of the known issues:
 * tcp packet from other connection can break a current one
 * tcp send sequence always starts from zero
 * bad tcp options processing
 * strange assumptions on packet size for selective acknowledge
 * tcp interface assumes one of the two scenarios:
     - data downloading from remote host to a board
     - request-response exchange with a small packets
   so it's not possible to upload large amount of data from the
   board to remote host.
 * wget test generate bad tcp stream, test should fail but it passes instead

This series of patches fixes all of the above issues.

The benefits:
 * A lot of bug was fixed
 * Better and more reliable TCP state machine
 * Tcp clients becomes smaller/simpler
 * Data uploading was fixed (now it's possible to transmit a huge amount of
   data from the board to remote host)

Modification was verified with
 * firmware downloading via u-boot wget command
 * fastboot over tcp
 * netcat linux client
 * Firefox/Chrome/Edge using example web-server implementation

Changes v2:
 * cover letter was added
 * some patches were removed

Changes v3:
 * better cover letter

Changes v4:
 * fix bug in debug output
 * add more comments
 * code style fixes

Changes v5:
 * old patches were occasionally sent with v4
 * add back web-server patches
 * fix bug in debug output
 * add more comments
 * code style fixes

Changes v6:
 * fix the wget test
 * improve description of "simplify tcp header filling code" patch

Changes v7:
 * fix include ordering
 * improve option descriptions
 * fix a lot of extra brackets and comparisons against NULL / 0
 * add empty lines before final returns
 * fixed a bug with zero size httpd uploads

Changes v8:
 * [tcp] add function to restart rx inactivity timeout. This may help
        in the cases where remote peer waits for u-boot data, but u-boot
        is busy with long executing action
 * [httpd] add function returning underlying tcp stream from request id.
        This (with the above change) allows avoid connection break
        for the long processing post requests.

Changes v9:
 * rebase all changes on top of origin/next
 * update test/cmd/wget patch description (bad tcp ack/seq issue was already
   fixed in origin/next)
 * tcp: add rx/tx packet counters to a tcp_stream structure
 * wget: use tcp rx packet counter instead of own one
 * netcat: use tcp rx/tx packet counters instead of own one

Changes v10:
 * netcat: fix bug appeared after rx/tx packet counter addition
 * rebased on top of v2024.10

Changes v11:
 * fix spelling in cover letter

Changes v12:
 * rebase on top of master branch (3df6145db0e)
 * slightly change tcp->rx() & tcp->tx() callback declarations, this
   allow us to terminate a connection if something goes wrong in rx/tx paths.
 * set net_boot_file_size variable in httpd_upload
 * set filesize env variable to a proper value netcat and httpd_upload

Changes v13:
 * rebase on top of master branch (8573ea41058)
 * remove netcat support
 * remove example httpd server implementation

Changes v14:
 * fix issues found by github CI

Mikhail Kshevetskiy (10):
  net/tcp: fix TCP options processing
  net/tcp: fix selective acknowledge
  net/tcp: put connection specific data into a tcp_stream structure
  net/tcp: add connection info to tcp_stream structure
  net/tcp: rename ack_edge and seq_init to more common rcv_nxt and irs
  net/tcp: improve tcp framework, use better state machine
  test/cmd/wget: fix the test
  net/tcp: simplify tcp header filling code
  net/tcp: define a fallback value for rcv_wnd size
  net/net: fix include ordering

 arch/sandbox/include/asm/eth.h |    4 +
 include/net-legacy.h           |    5 +-
 include/net/tcp.h              |  258 ++++++-
 include/net/wget.h             |    8 -
 net/fastboot_tcp.c             |  193 ++---
 net/net.c                      |   45 +-
 net/tcp.c                      | 1297 ++++++++++++++++++++++----------
 net/wget.c                     |  465 ++++--------
 test/cmd/wget.c                |   58 +-
 9 files changed, 1444 insertions(+), 889 deletions(-)

-- 
2.45.2