Andrew,
This version should address the comments you had on my initial
submission. Does this one look better now?
Thanks,
Daniel
On 6/20/20 9:39 PM, Daniel Mack wrote:
> The driver for Marvell switches puts all ports in IGMP snooping mode
> which results in all IGMP/MLD frames that ingress on the ports to be
> forwarded to the CPU only.
>
> The bridge code in the kernel can then interpret these frames and act
> upon them, for instance by updating the mdb in the switch to reflect
> multicast memberships of stations connected to the ports. However,
> the IGMP/MLD frames must then also be forwarded to other ports of the
> bridge so external IGMP queriers can track membership reports, and
> external multicast clients can receive query reports from foreign IGMP
> queriers.
>
> Currently, this is impossible as the EDSA tagger sets offload_fwd_mark
> on the skb when it unwraps the tagged frames, and that will make the
> switchdev layer prevent the skb from egressing on any other port of
> the same switch.
>
> To fix that, look at the To_CPU code in the DSA header and make
> forwarding of the frame possible for trapped IGMP packets.
>
> Introduce some #defines for the frame types to make the code a bit more
> comprehensive.
>
> This was tested on a Marvell 88E6352 variant.
>
> Signed-off-by: Daniel Mack <dan...@zonque.org>
> ---
> v2:
> * Limit IGMP handling to TO_CPU frames
> * Use #defines for the TO_CPU codes and the frame types
>
> net/dsa/tag_edsa.c | 37 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
> index e8eaa804ccb9e..d6200ff982007 100644
> --- a/net/dsa/tag_edsa.c
> +++ b/net/dsa/tag_edsa.c
> @@ -13,6 +13,16 @@
> #define DSA_HLEN 4
> #define EDSA_HLEN 8
>
> +#define FRAME_TYPE_TO_CPU 0x00
> +#define FRAME_TYPE_FORWARD 0x03
> +
> +#define TO_CPU_CODE_MGMT_TRAP 0x00
> +#define TO_CPU_CODE_FRAME2REG 0x01
> +#define TO_CPU_CODE_IGMP_MLD_TRAP 0x02
> +#define TO_CPU_CODE_POLICY_TRAP 0x03
> +#define TO_CPU_CODE_ARP_MIRROR 0x04
> +#define TO_CPU_CODE_POLICY_MIRROR 0x05
> +
> static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
> {
> struct dsa_port *dp = dsa_slave_to_port(dev);
> @@ -77,6 +87,8 @@ static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct
> net_device *dev,
> struct packet_type *pt)
> {
> u8 *edsa_header;
> + int frame_type;
> + int code;
> int source_device;
> int source_port;
>
> @@ -91,8 +103,29 @@ static struct sk_buff *edsa_rcv(struct sk_buff *skb,
> struct net_device *dev,
> /*
> * Check that frame type is either TO_CPU or FORWARD.
> */
> - if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0)
> + frame_type = edsa_header[0] >> 6;
> +
> + switch (frame_type) {
> + case FRAME_TYPE_TO_CPU:
> + code = (edsa_header[1] & 0x6) | ((edsa_header[2] >> 4) & 1);
> +
> + /*
> + * Mark the frame to never egress on any port of the same switch
> + * unless it's a trapped IGMP/MLD packet, in which case the
> + * bridge might want to forward it.
> + */
> + if (code != TO_CPU_CODE_IGMP_MLD_TRAP)
> + skb->offload_fwd_mark = 1;
> +
> + break;
> +
> + case FRAME_TYPE_FORWARD:
> + skb->offload_fwd_mark = 1;
> + break;
> +
> + default:
> return NULL;
> + }
>
> /*
> * Determine source device and port.
> @@ -156,8 +189,6 @@ static struct sk_buff *edsa_rcv(struct sk_buff *skb,
> struct net_device *dev,
> 2 * ETH_ALEN);
> }
>
> - skb->offload_fwd_mark = 1;
> -
> return skb;
> }
>
>
