Merge branch 'mlxsw-Add-one-armed-router-support'

Ido Schimmel says:

====================
mlxsw: Add one-armed router support

Up until now, when a packet was routed by the ASIC through the same
router interface (RIF) from which it ingressed from, the ASIC passed the
sole copy of the packet to the kernel. This allowed the kernel to route
the packet and also potentially generate an ICMP redirect.

There are scenarios (e.g., "one-armed router") where packets are
intentionally routed this way and are therefore not deemed as
exceptions. In such scenarios the current method of trapping packets to
the CPU is problematic, as it results in major packet loss.

This patchset solves the problem by having the ASIC forward the packet,
but also send a copy to the CPU, which gives the kernel the opportunity
to generate required exceptions.

To prevent the kernel from forwarding such packets again, the driver
marks them with 'offload_l3_fwd_mark', which causes the kernel to
consume them in ip{,6}_forward_finish().

Patch #1 renames 'offload_mr_fwd_mark' to 'offload_l3_fwd_mark'. When
set, the field indicates that a packet was already forwarded in L3
(unicast / multicast) by a capable device.

Patch #2 teaches the kernel to consume unicast packets that have
'offload_l3_fwd_mark' set.

Patch #3 changes mlxsw to mirror loopbacked (iRIF == eRIF) packets,
instead of trapping them.

Patch #4 adds a test case for above mentioned scenario.
====================

Signed-off-by: David S. Miller <[email protected]>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 75d50ab7997c..b1831a5ca173 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -616,6 +616,8 @@ typedef unsigned char *sk_buff_data_t;
  *	@pkt_type: Packet class
  *	@fclone: skbuff clone status
  *	@ipvs_property: skbuff is owned by ipvs
+ *	@offload_fwd_mark: Packet was L2-forwarded in hardware
+ *	@offload_l3_fwd_mark: Packet was L3-forwarded in hardware
  *	@tc_skip_classify: do not classify packet. set by IFB device
  *	@tc_at_ingress: used within tc_classify to distinguish in/egress
  *	@tc_redirected: packet was redirected by a tc action
@@ -799,7 +801,7 @@ struct sk_buff {
 	__u8			remcsum_offload:1;
 #ifdef CONFIG_NET_SWITCHDEV
 	__u8			offload_fwd_mark:1;
-	__u8			offload_mr_fwd_mark:1;
+	__u8			offload_l3_fwd_mark:1;
 #endif
 #ifdef CONFIG_NET_CLS_ACT
 	__u8			tc_skip_classify:1;