Merge branch 'net-bridge-mrp'

Horatiu Vultur says:

====================
net: bridge: mrp: Add support for Media Redundancy Protocol(MRP)

Media Redundancy Protocol is a data network protocol standardized by
International Electrotechnical Commission as IEC 62439-2. It allows rings of
Ethernet switches to overcome any single failure with recovery time faster than
STP. It is primarily used in Industrial Ethernet applications.

Based on the previous RFC[1][2][3][4][5], and patches[6][7][8], the MRP state
machine and all the timers were moved to userspace, except for the timers used
to generate MRP Test frames.  In this way the userspace doesn't know and should
not know if the HW or the kernel will generate the MRP Test frames. The
following changes were added to the bridge to support the MRP:
- the existing netlink interface was extended with MRP support,
- allow to detect when a MRP frame was received on a MRP ring port
- allow MRP instance to forward/terminate MRP frames
- generate MRP Test frames in case the HW doesn't have support for this

To be able to offload MRP support to HW, the switchdev API  was extend.

With these changes the userspace doesn't do the following because already the
kernel/HW will do:
- doesn't need to forward/terminate MRP frames
- doesn't need to generate MRP Test frames
- doesn't need to detect when the ring is open/closed.

The userspace application that is using the new netlink can be found here[9].

The current implementation both in kernel and userspace supports only 2 roles:
  MRM - this one is responsible to send MRP_Test and MRP_Topo frames on both
  ring ports. It needs to process MRP_Test to know if the ring is open or
  closed. This operation is desired to be offloaded to the HW because it
  requires to generate and process up to 4000 frames per second. Whenever it
  detects that the ring is open it sends MRP_Topo frames to notify all MRC about
  changes in the topology. MRM needs also to process MRP_LinkChange frames,
  these frames are generated by the MRC. When the ring is open then the state
  of both ports is to forward frames and when the ring is closed then the
  secondary port is blocked.

  MRC - this one is responsible to forward MRP frames between the ring ports.
  In case one of the ring ports gets a link down or up, then MRC will generate
  a MRP_LinkChange frames. This node should also process MRP_Topo frames and to
  clear its FDB when it receives this frame.

 Userspace
               Deamon +----------+ Client
                +
                |
 +--------------|-----------------------------------------+
  Kernel        |
                + Netlink

                |                              + Interrupt
                |                              |
 +--------------|------------------------------|----------+
  HW            | Switchdev                    |
                +                              |

The user interacts using the client (called 'mrp'), the client talks to the
deamon (called 'mrp_server'), which talks with the kernel using netlink. The
kernel will try to offload the requests to the HW via switchdev API.

If this will be accepted then in the future the netlink interface can be
expended with multiple attributes which are required by different roles of the
MRP. Like Media Redundancy Automanager(MRA), Media Interconnect Manager(MIM) and
Media Interconnect Client(MIC).

[1] https://www.spinics.net/lists/netdev/msg623647.html
[2] https://www.spinics.net/lists/netdev/msg624378.html
[3] https://www.spinics.net/lists/netdev/msg627500.html
[4] https://www.spinics.net/lists/netdev/msg641005.html
[5] https://www.spinics.net/lists/netdev/msg643991.html
[6] https://www.spinics.net/lists/netdev/msg645378.html
[7] https://www.spinics.net/lists/kernel/msg3484685.html
[8] https://www.spinics.net/lists/netdev/msg646202.html
[9] https://github.com/microchip-ung/mrp/tree/patch-v9

-v4:
  - fix comments in br_mrp.c
  - use skb_header_pointer to get br_mrp_tlv_hdr
  - fix line over 80 characters

-v3:
  - fix unused variables

-v2:
  - drop patch 4
  - add port flag BR_MRP_LOST_CONT;
  - another fix for bisectability

-v1:
  - fix bisectability issues
  - in case of errors use extack

-RFC v5:
  - use nla_parse_nested
  - rework the usage of the rcu in br_mrp
  - reorder patches
  - few other small issues raised by Nikolay

-RFC v4:
  - extend existing netlink interface to add mrp support
  - use rcu locks

-RFC v3:
  - move MRP state machine in userspace
  - create generic netlink interface for configuring the HW using switchdev API

-RFC v2:
  - extend switchdev API to offload to HW
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 128 insertions, 0 deletions

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index bfe621ea51b3..bd8c95488f16 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -120,6 +120,7 @@ enum {
 	IFLA_BRIDGE_MODE,
 	IFLA_BRIDGE_VLAN_INFO,
 	IFLA_BRIDGE_VLAN_TUNNEL_INFO,
+	IFLA_BRIDGE_MRP,
 	__IFLA_BRIDGE_MAX,
 };
 #define IFLA_BRIDGE_MAX (__IFLA_BRIDGE_MAX - 1)
@@ -157,6 +158,47 @@ struct bridge_vlan_xstats {
 	__u32 pad2;
 };
 
+enum {
+	IFLA_BRIDGE_MRP_UNSPEC,
+	IFLA_BRIDGE_MRP_INSTANCE,
+	IFLA_BRIDGE_MRP_PORT_STATE,
+	IFLA_BRIDGE_MRP_PORT_ROLE,
+	IFLA_BRIDGE_MRP_RING_STATE,
+	IFLA_BRIDGE_MRP_RING_ROLE,
+	IFLA_BRIDGE_MRP_START_TEST,
+	__IFLA_BRIDGE_MRP_MAX,
+};
+
+struct br_mrp_instance {
+	__u32 ring_id;
+	__u32 p_ifindex;
+	__u32 s_ifindex;
+};
+
+struct br_mrp_port_role {
+	__u32 ring_id;
+	__u32 role;
+};
+
+struct br_mrp_ring_state {
+	__u32 ring_id;
+	__u32 ring_state;
+};
+
+struct br_mrp_ring_role {
+	__u32 ring_id;
+	__u32 ring_role;
+};
+
+struct br_mrp_start_test {
+	__u32 ring_id;
+	__u32 interval;
+	__u32 max_miss;
+	__u32 period;
+};
+
+#define IFLA_BRIDGE_MRP_MAX (__IFLA_BRIDGE_MRP_MAX - 1)
+
 struct bridge_stp_xstats {
 	__u64 transition_blk;
 	__u64 transition_fwd;
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index f6ceb2e63d1e..d6de2b167448 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -92,6 +92,7 @@
 #define ETH_P_PREAUTH	0x88C7		/* 802.11 Preauthentication */
 #define ETH_P_TIPC	0x88CA		/* TIPC 			*/
 #define ETH_P_LLDP	0x88CC		/* Link Layer Discovery Protocol */
+#define ETH_P_MRP	0x88E3		/* Media Redundancy Protocol	*/
 #define ETH_P_MACSEC	0x88E5		/* 802.1ae MACsec */
 #define ETH_P_8021AH	0x88E7          /* 802.1ah Backbone Service Tag */
 #define ETH_P_MVRP	0x88F5          /* 802.1Q MVRP                  */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 127c704eeba9..a009365ad67b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -343,6 +343,7 @@ enum {
 	IFLA_BRPORT_NEIGH_SUPPRESS,
 	IFLA_BRPORT_ISOLATED,
 	IFLA_BRPORT_BACKUP_PORT,
+	IFLA_BRPORT_MRP_RING_OPEN,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
diff --git a/include/uapi/linux/mrp_bridge.h b/include/uapi/linux/mrp_bridge.h
new file mode 100644
index 000000000000..2600cdf5a284
--- /dev/null
+++ b/include/uapi/linux/mrp_bridge.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+
+#ifndef _UAPI_LINUX_MRP_BRIDGE_H_
+#define _UAPI_LINUX_MRP_BRIDGE_H_
+
+#include <linux/types.h>
+#include <linux/if_ether.h>
+
+#define MRP_MAX_FRAME_LENGTH		200
+#define MRP_DEFAULT_PRIO		0x8000
+#define MRP_DOMAIN_UUID_LENGTH		16
+#define MRP_VERSION			1
+#define MRP_FRAME_PRIO			7
+
+enum br_mrp_ring_role_type {
+	BR_MRP_RING_ROLE_DISABLED,
+	BR_MRP_RING_ROLE_MRC,
+	BR_MRP_RING_ROLE_MRM,
+};
+
+enum br_mrp_ring_state_type {
+	BR_MRP_RING_STATE_OPEN,
+	BR_MRP_RING_STATE_CLOSED,
+};
+
+enum br_mrp_port_state_type {
+	BR_MRP_PORT_STATE_DISABLED,
+	BR_MRP_PORT_STATE_BLOCKED,
+	BR_MRP_PORT_STATE_FORWARDING,
+	BR_MRP_PORT_STATE_NOT_CONNECTED,
+};
+
+enum br_mrp_port_role_type {
+	BR_MRP_PORT_ROLE_PRIMARY,
+	BR_MRP_PORT_ROLE_SECONDARY,
+	BR_MRP_PORT_ROLE_NONE,
+};
+
+enum br_mrp_tlv_header_type {
+	BR_MRP_TLV_HEADER_END = 0x0,
+	BR_MRP_TLV_HEADER_COMMON = 0x1,
+	BR_MRP_TLV_HEADER_RING_TEST = 0x2,
+	BR_MRP_TLV_HEADER_RING_TOPO = 0x3,
+	BR_MRP_TLV_HEADER_RING_LINK_DOWN = 0x4,
+	BR_MRP_TLV_HEADER_RING_LINK_UP = 0x5,
+};
+
+struct br_mrp_tlv_hdr {
+	__u8 type;
+	__u8 length;
+};
+
+struct br_mrp_end_hdr {
+	struct br_mrp_tlv_hdr hdr;
+};
+
+struct br_mrp_common_hdr {
+	__u16 seq_id;
+	__u8 domain[MRP_DOMAIN_UUID_LENGTH];
+};
+
+struct br_mrp_ring_test_hdr {
+	__u16 prio;
+	__u8 sa[ETH_ALEN];
+	__u16 port_role;
+	__u16 state;
+	__u16 transitions;
+	__u32 timestamp;
+};
+
+struct br_mrp_ring_topo_hdr {
+	__u16 prio;
+	__u8 sa[ETH_ALEN];
+	__u16 interval;
+};
+
+struct br_mrp_ring_link_hdr {
+	__u8 sa[ETH_ALEN];
+	__u16 port_role;
+	__u16 interval;
+	__u16 blocked;
+};
+
+#endif