[BUG] dhcp fails to download file with CONFIG_NET_LWIP=y

[Heinrich Schuchardt]

On 11/9/24 16:12, E Shattow wrote:
> On Sat, Nov 9, 2024 at 6:20 AM Heinrich Schuchardt
> <heinrich.schuchardt at canonical.com> wrote:
>>
>> Hello Jerome,
>>
>> Using the old network stack U-Boot's dhcp command can be used to
>> download via TFTP. This fails with the lwIP stack:
>>
>> StarFive # dhcp $kernel_addr_r 192.168.1.103:/vf2/grubriscv64.efi
>> ethernet at 16030000 Waiting for PHY auto negotiation to complete.... done
>> DHCP client bound to address 192.168.1.47 (233 ms)
>> StarFive # tftpboot $kernel_addr_r 192.168.1.103:/vf2/grubriscv64.efi
>> Using ethernet at 16030000 device
>> TFTP from server 192.168.1.103; our IP address is 192.168.1.47
>> Filename '/vf2/grubriscv64.efi'.
>> Load address: 0x40200000
>> Loading: #################################################################
>>            #################################################################
>>            #################################################################
>>            #################################################################
>>            #########
>>            4.1 MiB/s
>>
>> We should try to provide the old functionality to make the move to lwIP
>> seamless.
>>
>> In the CI QEMU instances we already have
>>
>> test/py/tests/test_net.py
>>
>> to test tftpboot. We should add an equivalent dhcp test.
>>
>> Best regards
>>
>> Heinrich
> 
> It is useful to have dhcp assignment without the side-effect of trying
> to load files. Your script can be updated to:

The dhcp command was explicitly built to support booting by retrieving a 
filename from the DHCP server and then loading it from a TFTP server. 
The recovery of many routers and IoT devices depends on this feature.

There is an environment variable autostart that controls if the file is 
only loaded or booted.

If we want to change the behavior, it should be via a well reviewed 
patch and not as a side-effect.

Best regards

Heinrich

> 
> dhcp ; tftpboot $kernel_addr_r 192.168.1.103:/vf2/grubriscv64.efi
> 
> I agree this is a change in the user interface, but this change makes
> sense to me. There needs to be a way to boot tftp using the DHCP
> optioned tftp server, but a command 'dhcp' does not have boot in the
> name it is not clear what this command does. All other commands that
> do a boot action have 'boot' in the name? Perhaps dhcpboot or to make
> tftpboot with an option to use DHCP options for the tftp server
> location.
> 
> I don't think 'dhcp' should do anything except DHCP.
> 
> -E