IEEE 802.1Q VLAN Support (IDFGH-7213)

[franz-ms-muc]

Is your feature request related to a problem? Please describe.

I'm always frustrated when Customers want to use IEEE 802.1Q VLAN Supported Networks (most Wifi, but sometimes Ethernet) with VLAN Support, and i have to use others than ESP32 Family Microcontrollers. Because we love ESP32, we would like to use them here as well.

Describe the solution you'd like

A clear and concise description of what you want to happen.
IEEE 802.1Q VLAN Support to be added to ESP-IDF.
https://de.wikipedia.org/wiki/IEEE_802.1Q

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.
https://zephyrproject.org/ has VLAN Support on ESP32. but i never tested this on ESP32, and i am unsure about the maturity it has, especially on the newest Chip: ESP32-S3

[david-cermak]

Hi @franz-ms-muc

lwIP supports basic VLAN functionality, as described here:

https://github.com/espressif/esp-lwip/blob/fb1f3552349bfa53d2977409f204d385ed0aa217/src/include/lwip/opt.h#L670-L675

It just checks the VLAN header ( 0x8100 /* 802.1Q VLAN tag */) and if enabled the packet could be processed or dropped based on user definition.

The easiest option is to

• enable VLAN: ETHARP_SUPPORT_VLAN=1
• define our VLAN header: ETHARP_VLAN_CHECK=*our_id*

It's also possible to define a function that receives the vlan header and decides what we want to do with the packet.
Here's the example:

Project Makefile:

idf_component_get_property(lwip lwip COMPONENT_LIB)
target_compile_options(${lwip} PRIVATE "-I${PROJECT_DIR}/main")
target_compile_definitions(${lwip} PRIVATE "-DETHARP_SUPPORT_VLAN=1" "-DLWIP_HOOK_VLAN_CHECK=vlan_hook" "-DESP_IDF_LWIP_HOOK_FILENAME=\"vlan_hook.h\"")

Hook header

#pragma once

struct netif;
struct eth_hdr;
struct eth_vlan_hdr;

int vlan_hook(struct netif *netif, struct eth_hdr *eth_hdr, struct eth_vlan_hdr *vlan_hdr);

Definition

#include "lwip/netif.h"
#include "lwip/etharp.h"

int vlan_hook(struct netif *netif, struct eth_hdr *eth_hdr, struct eth_vlan_hdr *vlan_hdr)
{
    // Processing (return 1 if for us)
    return 0;
}