On Fri, 11 Sep 2015 21:22:03 +0200
Phil Sutter <phil@xxxxxx> wrote:
> When forwarding packets from an 802.1Q interface with REORDER_HDR set to
> zero, the VLAN header previously inserted by vlan_do_receive() needs to
> be stripped from the packet and the mac_header adjustment undone,
> otherwise a tagged frame with first four bytes missing will be
> transmitted.
>
> Signed-off-by: Phil Sutter <phil@xxxxxx>
> ---
> net/bridge/br_input.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index f921a5d..e4e3fc7 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -288,6 +288,16 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
> }
>
> forward:
> + if (is_vlan_dev(skb->dev) &&
> + !(vlan_dev_priv(skb->dev)->flags & VLAN_FLAG_REORDER_HDR)) {
> + unsigned int offset = skb->data - skb_mac_header(skb);
> +
> + skb_push(skb, offset);
> + memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
> + skb->mac_header += VLAN_HLEN;
> + skb_pull(skb, offset);
> + skb_reset_mac_len(skb);
> + }
> switch (p->state) {
> case BR_STATE_FORWARDING:
> rhook = rcu_dereference(br_should_route_hook);
Thanks for finding this. Is this a new thing or has it always been there?
Sorry, this looks so special case it doesn't seem like a good idea.
Something is broken in VLAN handling if this is required.
