barebox + picotcp-1.7.0

[Antony Pavlov <antonynpavlov@gmail.com>]

Hi all!

In the message [1] Sascha proposed to have the barebox network stack
and picotcp in parallel.

This approach is used in the branch 20240303.picotcp-1.7.0 from
https://github.com/frantony/barebox/ repo [2]:

* all incoming packets go through the barebox network stack and only if
  they are not processed by it, they are forwarded to the picotcp network
  stack (all incoming ARP packets always go to the picotcp network stack).

* risc-v virtual qemu machine with user networking (slirp network stack)
  is used for demonstration; one needs only qemu risc-v emulator
  for demonstration;

* these barebox commands are introduced for picotcp stack capabilities
  demonstration:

  * dhclient --- setup picotcp network interface using the DHCP protocol;
  * ifconfig --- print/setup picotcp network interface information;
  * route --- print picotcp routing table;
  * picoping --- send ICMP ECHO_REQUEST to network hosts, receive replies;
  * picohost --- perform DNS lookup (google DNS server is used);
  * app_wget --- download file using the HTTP protocol.

* tcpdump code is incorporated into barebox for network stack debugging.
  tcpdump supports parsing most of the protocols supported by barebox
  (DHCP, ARP, ICMP, DNS, TFTP and TCP).

Please comment!

  [1] http://lists.infradead.org/pipermail/barebox/2024-February/045937.html
  [2] https://github.com/frantony/barebox/tree/20240303.picotcp-1.7.0

-- 
Best regards,
  Antony Pavlov