[U-Boot] net.c: question regarding commit: fd3056337e6fcc140f400e11edd33f6f1cb37de1

[Joe Hershberger]

Hi Hannes,

On Mon, Jun 22, 2015 at 7:23 AM, Hannes Schmelzer
<hannes at schmelzer.or.at> wrote:
> Hi joe,
>
> you did introduce callbacks on setting up ip,dns, ... in net.c
>
> Why it did become necessary to do following ?
>
>         if (flags & H_PROGRAMMATIC)
>                 return 0;

Because the callback should not be updating the network stack
variables when updated by the network stack (such as when DHCP sets
the ipaddr).

> I have actually trouble with this, because my code in
> board/BuR/kwb/board.c doesn't work anymore as expected.
>
>         /* setup default IP, in case if there is nothing in environment */
>         if (!getenv("ipaddr")) {
>                 setenv("ipaddr", "192.168.60.1");
>                 setenv("netmask", "255.255.255.0");
>                 setenv("serverip", "192.168.60.254");
>                 setenv("gatewayip", "192.168.60.254");
>                 puts("net: had no IP! made default setup.\n");
>         }
>
> Purpose of this was/is to setup a default ip-address if nothing in
> environment has been set yet.

Any reason not to use link-local or DHCP in this case? What are the
chances that the board is on a compatible network and no one else has
that address? I recommend you remove this code unless you have a
really good reason.

> do you (or somebody else) have an idea how to work around this ?

You can set the ipaddr as a user would... through the command line. I
actually had to change the way env edit worked in
94b467b14ed908c89a0780256e89b375aa3cf3ef (env: Distinguish finer
between source of env change). You can do something similar to what it
does now.

+               const char * const _argv[4] = { "setenv", argv[1], buffer,
+                       NULL };
+
+               return _do_env_set(0, 3, (char * const *)_argv, H_INTERACTIVE);

Cheers,
-Joe