Setting ipaddr via setenv() - H_INTERACTIVE vs H_PROGRAMMATIC

Hi Joe,

I'm currently stumbling over a problem in some board specific code (not in mainline yet), that sets the "ipaddr" env variable via setenv(). But as I now noticed, the callback on_ipaddr() doesn't set net_ip to this new value. As flags has H_PROGRAMMATIC set and op_ipaddr() skips setting this value in this case.

I fail to see why we need this check in on_ipaddr(). Could you please explain why this is needed? Why would someone use setenv() for the "ipaddr" and not want to also update the net_ip value. This results in the "ipaddr" value being updated but net_ip still being configured to the old value.

Or if this is really needed, what is the correct way to update the ipaddr (env variable and net_ip value) from the U-Boot code?

Quoted 8 lines · Stefan Roese

Hi Joe,

I'm currently stumbling over a problem in some board specific code (not in mainline yet), that sets the "ipaddr" env variable via setenv(). But as I now noticed, the callback on_ipaddr() doesn't set net_ip to this new value. As flags has H_PROGRAMMATIC set and op_ipaddr() skips setting this value in this case.

Quoted 5 lines

I fail to see why we need this check in on_ipaddr(). Could you please explain why this is needed? Why would someone use setenv() for the "ipaddr" and not want to also update the net_ip value. This results in the "ipaddr" value being updated but net_ip still being configured to the old value.

The purpose is that programmatic accesses may write directly to the net_ip variable, but the user on the console cannot. This is because the "programmatic" accesses to these variables is expected to be things like the dhcp command and the linklocal command after successful netloop.

You can see this call in the netboot_update_env()
function in cmd/net.c.

Quoted 2 lines

Or if this is really needed, what is the correct way to update the ipaddr (env variable and net_ip value) from the U-Boot code?

You can work around it in a similar way to what I did in the initial change (94b467b14ed908c89a0780256e89b375aa3cf3ef - env: Distinguish finer between source of env change). The do_env_edit function used to call setenv, but I changed it to call as though it was interactive. You could do the same thing in your board driver.

Hi Joe,

(adding Tom to Cc as this seems to be a fundamental issue)

Quoted 15 lines · Joe Hershberger

Quoted 8 lines · Stefan Roese

Hi Joe,

I'm currently stumbling over a problem in some board specific code (not in mainline yet), that sets the "ipaddr" env variable via setenv(). But as I now noticed, the callback on_ipaddr() doesn't set net_ip to this new value. As flags has H_PROGRAMMATIC set and op_ipaddr() skips setting this value in this case.

Quoted 5 lines

I fail to see why we need this check in on_ipaddr(). Could you please explain why this is needed? Why would someone use setenv() for the "ipaddr" and not want to also update the net_ip value. This results in the "ipaddr" value being updated but net_ip still being configured to the old value.

Quoted 5 lines

The purpose is that programmatic accesses may write directly to the net_ip variable, but the user on the console cannot. This is because the "programmatic" accesses to these variables is expected to be things like the dhcp command and the linklocal command after successful netloop.

Please correct me, but it seems to be implemented the other way around. If H_PROGRAMMATIC is set (called via setenv()) the net variables (net_ip...) will *not* be set:

static int on_ipaddr(const char *name, const char *value, enum env_op op,
int flags)

{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_ip = string_to_ip(value);

        return 0;
}

Quoted 2 lines

You can see this call in the netboot_update_env()
function in cmd/net.c.

netboot_update_env() does not update the internal variables. At least not in my tests. op_ipaddr() returns directly after the "flags" check (see above).

I've checked how "dhcp" works. And here the variables are updated in store_net_params() via explicit net_copy_ip() calls.

Quoted 8 lines

Quoted 2 lines

Or if this is really needed, what is the correct way to update the ipaddr (env variable and net_ip value) from the U-Boot code?

You can work around it in a similar way to what I did in the initial change (94b467b14ed908c89a0780256e89b375aa3cf3ef - env: Distinguish finer between source of env change). The do_env_edit function used to call setenv, but I changed it to call as though it was interactive. You could do the same thing in your board driver.

Again, my findings are that this is implemented the other way around. setenv from the user via the command "setenv ipaddr ..." will update the net_ip variable. And code that calls setenv() will not.

I still fails to see why one of both should not update the net_ip (and others) variable. From my understanding setenv() from code and "setenv ipaddr ..." from the prompt should update the internal variables.

Thanks,
Stefan

Quoted 44 lines · Stefan Roese

Hi Joe,

(adding Tom to Cc as this seems to be a fundamental issue)

Quoted 15 lines · Joe Hershberger

Quoted 8 lines · Stefan Roese

Hi Joe,

I'm currently stumbling over a problem in some board specific code (not in mainline yet), that sets the "ipaddr" env variable via setenv(). But as I now noticed, the callback on_ipaddr() doesn't set net_ip to this new value. As flags has H_PROGRAMMATIC set and op_ipaddr() skips setting this value in this case.

Quoted 5 lines

I fail to see why we need this check in on_ipaddr(). Could you please explain why this is needed? Why would someone use setenv() for the "ipaddr" and not want to also update the net_ip value. This results in the "ipaddr" value being updated but net_ip still being configured to the old value.

Quoted 5 lines

The purpose is that programmatic accesses may write directly to the net_ip variable, but the user on the console cannot. This is because the "programmatic" accesses to these variables is expected to be things like the dhcp command and the linklocal command after successful netloop.

Please correct me, but it seems to be implemented the other way around. If H_PROGRAMMATIC is set (called via setenv()) the net variables (net_ip...) will *not* be set:

static int on_ipaddr(const char *name, const char *value, enum env_op op,
int flags)

{
         if (flags & H_PROGRAMMATIC)
                 return 0;

         net_ip = string_to_ip(value);

         return 0;
}

Quoted 2 lines

You can see this call in the netboot_update_env()
function in cmd/net.c.

Quoted 3 lines

netboot_update_env() does not update the internal variables. At least not in my tests. op_ipaddr() returns directly after the "flags" check (see above).

That's exactly the point. It doesn't set the internal variables because the source *is* the internal variables.

Hi Joe,

Quoted 52 lines · Joe Hershberger

Quoted 50 lines · Stefan Roese

Hi Joe,

(adding Tom to Cc as this seems to be a fundamental issue)

Quoted 18 lines · Joe Hershberger

Quoted 9 lines · Stefan Roese

Hi Joe,

I'm currently stumbling over a problem in some board specific code (not in mainline yet), that sets the "ipaddr" env variable via setenv(). But as I now noticed, the callback on_ipaddr() doesn't set net_ip to this new value. As flags has H_PROGRAMMATIC set and op_ipaddr() skips setting this value in this case.

Quoted 5 lines

I fail to see why we need this check in on_ipaddr(). Could you please explain why this is needed? Why would someone use setenv() for the "ipaddr" and not want to also update the net_ip value. This results in the "ipaddr" value being updated but net_ip still being configured to the old value.

Quoted 5 lines

The purpose is that programmatic accesses may write directly to the net_ip variable, but the user on the console cannot. This is because the "programmatic" accesses to these variables is expected to be things like the dhcp command and the linklocal command after successful netloop.

Please correct me, but it seems to be implemented the other way around. If H_PROGRAMMATIC is set (called via setenv()) the net variables (net_ip...) will *not* be set:

static int on_ipaddr(const char *name, const char *value, enum env_op op,
int flags)

{
         if (flags & H_PROGRAMMATIC)
                 return 0;

         net_ip = string_to_ip(value);

         return 0;
}

Quoted 2 lines

You can see this call in the netboot_update_env()
function in cmd/net.c.

Quoted 7 lines

Quoted 3 lines

netboot_update_env() does not update the internal variables. At least not in my tests. op_ipaddr() returns directly after the "flags" check (see above).

That's exactly the point. It doesn't set the internal variables because the source *is* the internal variables.

Now I understand what you mean. The PROGRAMMATIC approach should set the variables directly. I'll set the net_ip variable directly from the board specific code then.

But again, why exactly do we need to distinguish between this interactive and programmatic access? Why not set the internal variables every time the special env variables are set (interactively and programmatically)?