From bf5bc3ce8a8f32a0d45b6820ede8f9fc3e9c23df Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Thu, 2 May 2019 23:23:33 +0300 Subject: [PATCH] ether: Add dedicated Ethertype for pseudo-802.1Q DSA tagging There are two possible utilizations so far: - Switch devices that don't support a native insertion/extraction header on the CPU port may still enjoy the benefits of port isolation with a custom VLAN tag. For this, they need to have a customizable TPID in hardware and a new Ethertype to distinguish between real 802.1Q traffic and the private tags used for port separation. - Switches that don't support the deactivation of VLAN awareness, but still want to have a mode in which they accept all traffic, including frames that are tagged with a VLAN not configured on their ports, may use this as a fake to trick the hardware into thinking that the TPID for VLAN is something other than 0x8100. What follows after the ETH_P_DSA_8021Q EtherType is a regular VLAN header (TCI), however there is no other EtherType that can be used for this purpose and doesn't already have a well-defined meaning. ETH_P_8021AD, ETH_P_QINQ1, ETH_P_QINQ2 and ETH_P_QINQ3 expect that another follow-up VLAN tag is present, which is not the case here. Signed-off-by: Vladimir Oltean Suggested-by: Andrew Lunn Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller --- include/uapi/linux/if_ether.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h index 3a45b4ad71a3..3158ba672b72 100644 --- a/include/uapi/linux/if_ether.h +++ b/include/uapi/linux/if_ether.h @@ -109,6 +109,7 @@ #define ETH_P_QINQ2 0x9200 /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */ #define ETH_P_QINQ3 0x9300 /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */ #define ETH_P_EDSA 0xDADA /* Ethertype DSA [ NOT AN OFFICIALLY REGISTERED ID ] */ +#define ETH_P_DSA_8021Q 0xDADB /* Fake VLAN Header for DSA [ NOT AN OFFICIALLY REGISTERED ID ] */ #define ETH_P_IFE 0xED3E /* ForCES inter-FE LFB type */ #define ETH_P_AF_IUCV 0xFBFB /* IBM af_iucv [ NOT AN OFFICIALLY REGISTERED ID ] */ -- 2.39.5