VID 0 is not a valid VLAN according to "802.1Q-2011" "Table 9-2—Reserved VID values". It is only used to indicate "priority tag" frames which only contain priority information and no VID.
The 8021q is also redirecting the priority tagged frames to the underlying interface since commit ad1afb003939 ("vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)"). But at the same time, it automatically adds the VID 0 to all devices to ensure that VID 0 is in the allowed list of the HW filter. This resulted in a VLAN 0 which was always announced in OGM messages.
batman-adv should therefore not create a new batadv_softif_vlan for VID 0 and handle all VID 0 related frames using the "untagged" global/local translation tables.
Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/main.c | 7 +++++++ net/batman-adv/soft-interface.c | 14 ++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c index 8e0f44c71696f642d80304ec2724e8b5e56a5d93..333e947afcce7ca4128be8406f23295df723515c 100644 --- a/net/batman-adv/main.c +++ b/net/batman-adv/main.c @@ -637,6 +637,13 @@ unsigned short batadv_get_vid(struct sk_buff *skb, size_t header_len)
vhdr = (struct vlan_ethhdr *)(skb->data + header_len); vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK; + + /* VID 0 is only used to indicate "priority tag" frames which only + * contain priority information and no VID. + */ + if (vid == 0) + return BATADV_NO_FLAGS; + vid |= BATADV_VLAN_HAS_TAG;
return vid; diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 1f06861bc86a7d23c48d91e61298f48f6ec6b3f9..282a8f9b144471b12f62a547b3e57666cbb22c6d 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -637,6 +637,14 @@ static int batadv_interface_add_vid(struct net_device *dev, __be16 proto, if (proto != htons(ETH_P_8021Q)) return -EINVAL;
+ /* VID 0 is only used to indicate "priority tag" frames which only + * contain priority information and no VID. No management structures + * should be created for this VID and it should be handled like an + * untagged frame. + */ + if (vid == 0) + return 0; + vid |= BATADV_VLAN_HAS_TAG;
/* if a new vlan is getting created and it already exists, it means that @@ -684,6 +692,12 @@ static int batadv_interface_kill_vid(struct net_device *dev, __be16 proto, if (proto != htons(ETH_P_8021Q)) return -EINVAL;
+ /* "priority tag" frames are handled like "untagged" frames + * and no softif_vlan needs to be destroyed + */ + if (vid == 0) + return 0; + vlan = batadv_softif_vlan_get(bat_priv, vid | BATADV_VLAN_HAS_TAG); if (!vlan) return -ENOENT;
--- base-commit: 4e395d4d6908da373f00752c363c82ccf99a427e change-id: 20241216-no-vlan-0-5855407b9c6c
Best regards,