dsa: Allow forwarding of redirected IGMP traffic (1ed9ec9b) · Commits · 戴 / test

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 <daniel@zonque.org> Reviewed-by:

Andrew Lunn <andrew@lunn.ch> Tested-by:

Andrew Lunn <andrew@lunn.ch> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/dsa/tag_edsa.c

+34 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}

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