drivers/ethernet/eth_stm32_hal.c: net_pkt_write fails, when packet has size 1518

[clamattia]

When the system receives a packet with maximum payload (size 1518 including header), the driver fails with <err> eth_stm32_hal: eth_rx: Failed to append RX buffer to context buffer, rx_header->size=1518 (I added the length to the message).
This happens consistenly (we are using an ethernet test setup).

To reproduce, send a packet with maximum size.

Expected: The system does not fail, even with packets of maximal payload length.

Impact: This makes the driver unusable for our project. We need to find a solution.

Let me know if additional information is needed or, if I may test a patch on our setup.

[clamattia]

Still some length to go 4

[clamattia]

Yes, allocation is faulty:
Data allocation maximum size 1514 (requested 1518)

Please also make it a warning in case we allocate less then requested and change message to Data allocation size 1514 (requested 1518), because it is not the 'maximum' it is the actual allocation size.

[clamattia]

This would for example fix the problem. But maybe it is also somewhere else with NET_ETH_MAX_HDR_SIZE.

-ETH_NET_DEVICE_DT_INST_DEFINE(0, eth_initialize,
-		    NULL, &eth0_data, &eth0_config,
-		    CONFIG_ETH_INIT_PRIORITY, &eth_api, ETH_STM32_HAL_MTU);
+ETH_NET_DEVICE_DT_INST_DEFINE(0, eth_initialize,
+		    NULL, &eth0_data, &eth0_config,
+		    CONFIG_ETH_INIT_PRIORITY, &eth_api, ETH_STM32_HAL_FRAME_SIZE_MAX);