Changes:
 * Fix initial send sequence always zero issue
 * Use state machine close to RFC 9293. This should make TCP
   transfers more reliable (now we can upload a huge array
   of data from the board to external server)
 * Improve TCP framework a lot. This should make tcp client
   code much more simple.
 * rewrite wget with new tcp stack
 * rewrite fastboot_tcp with new tcp stack

It's quite hard to fix the initial send sequence (ISS) issue
with the separate patch. A naive attempt to fix an issue
inside the tcp_set_tcp_header() function will break tcp packet
retransmit logic in wget and other clients.

Example:
  Wget stores tcp_seq_num value before tcp_set_tcp_header() will
  be called and (on failure) retransmit the packet with the stored
  tcp_seq_num value. Thus:
    * the same ISS must allways be used (current case)
    * or tcp clients needs to generate a proper ISS when
      required.

A proper ISS fix will require a big redesing comparable with
a this one.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Reviewed-by: Simon Glass <sjg@chromium.org>

Currently the wget command is hard wired to HTTP port 80. This is
inconvenient, as it is extremely easy to start trivial HTTP server
as an unprivileged user using e.g. python http module to serve the
files, but such a server has to run on one of the higher ports:
"
$ python3 -m http.server -d $(pwd) 8080
"

Make it possible to configure HTTP server port the same way it is
possible to configure TFTP server port, using environment variable
'httpdstp' (similar to 'tftpdstp'). Retain port 80 as the default
fallback port. This way, users can start their own trivial server
and conveniently download whatever files they need into U-Boot.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

This commit adds a simple wget command that can download files
from http server.

The command syntax is
wget ${loadaddr} <path of the file from server>

Signed-off-by: Duncan Hare <DuncanCHare@yahoo.com>
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>