[PATCH v11 00/13] net: tcp: improve tcp support

[Mikhail Kshevetskiy]

U-Boot support of LWIP is not ready for a moment, but we already have
some kind of tcp support. Unfortunately this support is really bad.

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)
 * Netcat over tcp was implemented. Netcat supports data downloading/uploading
   from/to remote host in client/server mode.
 * An example web-server implementation. This code can be used as a base
   for web-based firmware uploading used by some vendors.

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

Mikhail Kshevetskiy (13):
  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
  net/netcat: add netcat over tcp support
  net/httpd: add httpd common code
  net/httpd-upload: an example web-server implementation for file
    uploading

 arch/sandbox/include/asm/eth.h |    4 +
 cmd/Kconfig                    |   35 +
 cmd/net.c                      |   55 +-
 include/net.h                  |    7 +-
 include/net/httpd-upload.h     |   12 +
 include/net/httpd.h            |   71 ++
 include/net/netcat.h           |   20 +
 include/net/tcp.h              |  254 ++++++-
 include/net/wget.h             |    8 -
 net/Kconfig                    |   14 +
 net/Makefile                   |    3 +
 net/fastboot_tcp.c             |  193 +++--
 net/httpd-upload.c             |  170 +++++
 net/httpd.c                    |  735 ++++++++++++++++++
 net/net.c                      |   60 +-
 net/netcat.c                   |  191 +++++
 net/tcp.c                      | 1266 ++++++++++++++++++++++----------
 net/wget.c                     |  476 ++++--------
 test/cmd/wget.c                |   58 +-
 19 files changed, 2723 insertions(+), 909 deletions(-)
 create mode 100644 include/net/httpd-upload.h
 create mode 100644 include/net/httpd.h
 create mode 100644 include/net/netcat.h
 create mode 100644 net/httpd-upload.c
 create mode 100644 net/httpd.c
 create mode 100644 net/netcat.c

-- 
2.45.2