[PATCH net-next 2/2] bridge: mrp: Add support for role MRA

From: Horatiu Vultur
Date: Fri May 29 2020 - 04:06:03 EST

A node that has the MRA role, it can behave as MRM or MRC.

Initially it starts as MRM and sends MRP_Test frames on both ring ports.
If it detects that there are MRP_Test send by another MRM, then it
checks if these frames have a lower priority than itself. In this case
it would send MRP_Nack frames to notify the other node that it needs to
stop sending MRP_Test frames.
If it receives a MRP_Nack frame then it stops sending MRP_Test frames
and starts to behave as a MRC but it would continue to monitor the
MRP_Test frames send by MRM. If at a point the MRM stops to send
MRP_Test frames it would get the MRM role and start to send MRP_Test
frames.

Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
include/net/switchdev.h | 1 +
include/uapi/linux/if_bridge.h | 2 +
include/uapi/linux/mrp_bridge.h | 38 ++++++++++
net/bridge/br_mrp.c | 125 +++++++++++++++++++++++++++-----
net/bridge/br_mrp_netlink.c | 6 ++
net/bridge/br_mrp_switchdev.c | 4 +-
net/bridge/br_private_mrp.h | 4 +-
7 files changed, 159 insertions(+), 21 deletions(-)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index f82ef4c45f5ed..b8c059b4e06d9 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -130,6 +130,7 @@ struct switchdev_obj_ring_test_mrp {
u8 max_miss;
u32 ring_id;
u32 period;
+ bool monitor;
};

#define SWITCHDEV_OBJ_RING_TEST_MRP(OBJ) \
diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 0162c1370ecb6..caa6914a3e53a 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -222,6 +222,7 @@ enum {
IFLA_BRIDGE_MRP_START_TEST_INTERVAL,
IFLA_BRIDGE_MRP_START_TEST_MAX_MISS,
IFLA_BRIDGE_MRP_START_TEST_PERIOD,
+ IFLA_BRIDGE_MRP_START_TEST_MONITOR,
__IFLA_BRIDGE_MRP_START_TEST_MAX,
};

@@ -249,6 +250,7 @@ struct br_mrp_start_test {
__u32 interval;
__u32 max_miss;
__u32 period;
+ __u32 monitor;
};

struct bridge_stp_xstats {
diff --git a/include/uapi/linux/mrp_bridge.h b/include/uapi/linux/mrp_bridge.h
index 2600cdf5a2848..ba248cbbc751e 100644
--- a/include/uapi/linux/mrp_bridge.h
+++ b/include/uapi/linux/mrp_bridge.h
@@ -11,11 +11,14 @@
#define MRP_DOMAIN_UUID_LENGTH 16
#define MRP_VERSION 1
#define MRP_FRAME_PRIO 7
+#define MRP_OUI_LENGTH 3
+#define MRP_MANUFACTURE_DATA_LENGTH 2

enum br_mrp_ring_role_type {
BR_MRP_RING_ROLE_DISABLED,
BR_MRP_RING_ROLE_MRC,
BR_MRP_RING_ROLE_MRM,
+ BR_MRP_RING_ROLE_MRA,
};

enum br_mrp_ring_state_type {
@@ -43,6 +46,13 @@ enum br_mrp_tlv_header_type {
BR_MRP_TLV_HEADER_RING_TOPO = 0x3,
BR_MRP_TLV_HEADER_RING_LINK_DOWN = 0x4,
BR_MRP_TLV_HEADER_RING_LINK_UP = 0x5,
+ BR_MRP_TLV_HEADER_OPTION = 0x7f,
+};
+
+enum br_mrp_sub_tlv_header_type {
+ BR_MRP_SUB_TLV_HEADER_TEST_MGR_NACK = 0x1,
+ BR_MRP_SUB_TLV_HEADER_TEST_PROPAGATE = 0x2,
+ BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR = 0x3,
};

struct br_mrp_tlv_hdr {
@@ -50,6 +60,11 @@ struct br_mrp_tlv_hdr {
__u8 length;
};

+struct br_mrp_sub_tlv_hdr {
+ __u8 type;
+ __u8 length;
+};
+
struct br_mrp_end_hdr {
struct br_mrp_tlv_hdr hdr;
};
@@ -81,4 +96,27 @@ struct br_mrp_ring_link_hdr {
__u16 blocked;
};

+struct br_mrp_sub_opt_hdr {
+ __u8 type;
+ __u8 manufacture_data[MRP_MANUFACTURE_DATA_LENGTH];
+};
+
+struct br_mrp_test_mgr_nack_hdr {
+ __u16 prio;
+ __u8 sa[ETH_ALEN];
+ __u16 other_prio;
+ __u8 other_sa[ETH_ALEN];
+};
+
+struct br_mrp_test_prop_hdr {
+ __u16 prio;
+ __u8 sa[ETH_ALEN];
+ __u16 other_prio;
+ __u8 other_sa[ETH_ALEN];
+};
+
+struct br_mrp_oui_hdr {
+ __u8 oui[MRP_OUI_LENGTH];
+};
+
#endif
diff --git a/net/bridge/br_mrp.c b/net/bridge/br_mrp.c
index f8fd037219fe9..24986ec7d38cc 100644
--- a/net/bridge/br_mrp.c
+++ b/net/bridge/br_mrp.c
@@ -160,6 +160,16 @@ static struct sk_buff *br_mrp_alloc_test_skb(struct br_mrp *mrp,
return skb;
}

+/* This function is continuously called in the following cases:
+ * - when node role is MRM, in this case test_monitor is always set to false
+ * because it needs to notify the userspace that the ring is open and needs to
+ * send MRP_Test frames
+ * - when node role is MRA, there are 2 subcases:
+ * - when MRA behaves as MRM, in this case is similar with MRM role
+ * - when MRA behaves as MRC, in this case test_monitor is set to true,
+ * because it needs to detect when it stops seeing MRP_Test frames
+ * from MRM node but it doesn't need to send MRP_Test frames.
+ */
static void br_mrp_test_work_expired(struct work_struct *work)
{
struct delayed_work *del_work = to_delayed_work(work);
@@ -177,8 +187,14 @@ static void br_mrp_test_work_expired(struct work_struct *work)
/* Notify that the ring is open only if the ring state is
* closed, otherwise it would continue to notify at every
* interval.
+ * Also notify that the ring is open when the node has the
+ * role MRA and behaves as MRC. The reason is that the
+ * userspace needs to know when the MRM stopped sending
+ * MRP_Test frames so that the current node to try to take
+ * the role of a MRM.
*/
- if (mrp->ring_state == BR_MRP_RING_STATE_CLOSED)
+ if (mrp->ring_state == BR_MRP_RING_STATE_CLOSED ||
+ mrp->test_monitor)
notify_open = true;
}

@@ -186,12 +202,15 @@ static void br_mrp_test_work_expired(struct work_struct *work)

p = rcu_dereference(mrp->p_port);
if (p) {
- skb = br_mrp_alloc_test_skb(mrp, p, BR_MRP_PORT_ROLE_PRIMARY);
- if (!skb)
- goto out;
-
- skb_reset_network_header(skb);
- dev_queue_xmit(skb);
+ if (!mrp->test_monitor) {
+ skb = br_mrp_alloc_test_skb(mrp, p,
+ BR_MRP_PORT_ROLE_PRIMARY);
+ if (!skb)
+ goto out;
+
+ skb_reset_network_header(skb);
+ dev_queue_xmit(skb);
+ }

if (notify_open && !mrp->ring_role_offloaded)
br_mrp_port_open(p->dev, true);
@@ -199,12 +218,15 @@ static void br_mrp_test_work_expired(struct work_struct *work)

p = rcu_dereference(mrp->s_port);
if (p) {
- skb = br_mrp_alloc_test_skb(mrp, p, BR_MRP_PORT_ROLE_SECONDARY);
- if (!skb)
- goto out;
-
- skb_reset_network_header(skb);
- dev_queue_xmit(skb);
+ if (!mrp->test_monitor) {
+ skb = br_mrp_alloc_test_skb(mrp, p,
+ BR_MRP_PORT_ROLE_SECONDARY);
+ if (!skb)
+ goto out;
+
+ skb_reset_network_header(skb);
+ dev_queue_xmit(skb);
+ }

if (notify_open && !mrp->ring_role_offloaded)
br_mrp_port_open(p->dev, true);
@@ -227,7 +249,7 @@ static void br_mrp_del_impl(struct net_bridge *br, struct br_mrp *mrp)

/* Stop sending MRP_Test frames */
cancel_delayed_work_sync(&mrp->test_work);
- br_mrp_switchdev_send_ring_test(br, mrp, 0, 0, 0);
+ br_mrp_switchdev_send_ring_test(br, mrp, 0, 0, 0, 0);

br_mrp_switchdev_del(br, mrp);

@@ -452,8 +474,8 @@ int br_mrp_set_ring_role(struct net_bridge *br,
return 0;
}

-/* Start to generate MRP test frames, the frames are generated by HW and if it
- * fails, they are generated by the SW.
+/* Start to generate or monitor MRP test frames, the frames are generated by
+ * HW and if it fails, they are generated by the SW.
* note: already called with rtnl_lock
*/
int br_mrp_start_test(struct net_bridge *br,
@@ -464,16 +486,18 @@ int br_mrp_start_test(struct net_bridge *br,
if (!mrp)
return -EINVAL;

- /* Try to push it to the HW and if it fails then continue to generate in
- * SW and if that also fails then return error
+ /* Try to push it to the HW and if it fails then continue with SW
+ * implementation and if that also fails then return error.
*/
if (!br_mrp_switchdev_send_ring_test(br, mrp, test->interval,
- test->max_miss, test->period))
+ test->max_miss, test->period,
+ test->monitor))
return 0;

mrp->test_interval = test->interval;
mrp->test_end = jiffies + usecs_to_jiffies(test->period);
mrp->test_max_miss = test->max_miss;
+ mrp->test_monitor = test->monitor;
mrp->test_count_miss = 0;
queue_delayed_work(system_wq, &mrp->test_work,
usecs_to_jiffies(test->interval));
@@ -510,6 +534,57 @@ static void br_mrp_mrm_process(struct br_mrp *mrp, struct net_bridge_port *port,
br_mrp_port_open(port->dev, false);
}

+/* Determin if the test hdr has a better priority than the node */
+static bool br_mrp_test_better_than_own(struct br_mrp *mrp,
+ struct net_bridge *br,
+ const struct br_mrp_ring_test_hdr *hdr)
+{
+ u16 prio = be16_to_cpu(hdr->prio);
+
+ if (prio < mrp->prio ||
+ (prio == mrp->prio &&
+ ether_addr_to_u64(hdr->sa) < ether_addr_to_u64(br->dev->dev_addr)))
+ return true;
+
+ return false;
+}
+
+/* Process only MRP Test frame. All the other MRP frames are processed by
+ * userspace application
+ * note: already called with rcu_read_lock
+ */
+static void br_mrp_mra_process(struct br_mrp *mrp, struct net_bridge *br,
+ struct net_bridge_port *port,
+ struct sk_buff *skb)
+{
+ const struct br_mrp_ring_test_hdr *test_hdr;
+ struct br_mrp_ring_test_hdr _test_hdr;
+ const struct br_mrp_tlv_hdr *hdr;
+ struct br_mrp_tlv_hdr _hdr;
+
+ /* Each MRP header starts with a version field which is 16 bits.
+ * Therefore skip the version and get directly the TLV header.
+ */
+ hdr = skb_header_pointer(skb, sizeof(uint16_t), sizeof(_hdr), &_hdr);
+ if (!hdr)
+ return;
+
+ if (hdr->type != BR_MRP_TLV_HEADER_RING_TEST)
+ return;
+
+ test_hdr = skb_header_pointer(skb, sizeof(uint16_t) + sizeof(_hdr),
+ sizeof(_test_hdr), &_test_hdr);
+ if (!test_hdr)
+ return;
+
+ /* Only frames that have a better priority than the node will
+ * clear the miss counter because otherwise the node will need to behave
+ * as MRM.
+ */
+ if (br_mrp_test_better_than_own(mrp, br, test_hdr))
+ mrp->test_count_miss = 0;
+}
+
/* This will just forward the frame to the other mrp ring port(MRC role) or will
* not do anything.
* note: already called with rcu_read_lock
@@ -546,6 +621,18 @@ static int br_mrp_rcv(struct net_bridge_port *p,
return 1;
}

+ /* If the role is MRA then don't forward the frames if it behaves as
+ * MRM node
+ */
+ if (mrp->ring_role == BR_MRP_RING_ROLE_MRA) {
+ if (!mrp->test_monitor) {
+ br_mrp_mrm_process(mrp, p, skb);
+ return 1;
+ }
+
+ br_mrp_mra_process(mrp, br, p, skb);
+ }
+
/* Clone the frame and forward it on the other MRP port */
nskb = skb_clone(skb, GFP_ATOMIC);
if (!nskb)
diff --git a/net/bridge/br_mrp_netlink.c b/net/bridge/br_mrp_netlink.c
index 332d9894a9485..32acf8a738f9e 100644
--- a/net/bridge/br_mrp_netlink.c
+++ b/net/bridge/br_mrp_netlink.c
@@ -196,6 +196,7 @@ br_mrp_start_test_policy[IFLA_BRIDGE_MRP_START_TEST_MAX + 1] = {
[IFLA_BRIDGE_MRP_START_TEST_INTERVAL] = { .type = NLA_U32 },
[IFLA_BRIDGE_MRP_START_TEST_MAX_MISS] = { .type = NLA_U32 },
[IFLA_BRIDGE_MRP_START_TEST_PERIOD] = { .type = NLA_U32 },
+ [IFLA_BRIDGE_MRP_START_TEST_MONITOR] = { .type = NLA_U32 },
};

static int br_mrp_start_test_parse(struct net_bridge *br, struct nlattr *attr,
@@ -225,6 +226,11 @@ static int br_mrp_start_test_parse(struct net_bridge *br, struct nlattr *attr,
test.interval = nla_get_u32(tb[IFLA_BRIDGE_MRP_START_TEST_INTERVAL]);
test.max_miss = nla_get_u32(tb[IFLA_BRIDGE_MRP_START_TEST_MAX_MISS]);
test.period = nla_get_u32(tb[IFLA_BRIDGE_MRP_START_TEST_PERIOD]);
+ test.monitor = false;
+
+ if (tb[IFLA_BRIDGE_MRP_START_TEST_MONITOR])
+ test.monitor =
+ nla_get_u32(tb[IFLA_BRIDGE_MRP_START_TEST_MONITOR]);

return br_mrp_start_test(br, &test);
}
diff --git a/net/bridge/br_mrp_switchdev.c b/net/bridge/br_mrp_switchdev.c
index 3a776043bf80d..0da68a0da4b5a 100644
--- a/net/bridge/br_mrp_switchdev.c
+++ b/net/bridge/br_mrp_switchdev.c
@@ -65,7 +65,8 @@ int br_mrp_switchdev_set_ring_role(struct net_bridge *br,

int br_mrp_switchdev_send_ring_test(struct net_bridge *br,
struct br_mrp *mrp, u32 interval,
- u8 max_miss, u32 period)
+ u8 max_miss, u32 period,
+ bool monitor)
{
struct switchdev_obj_ring_test_mrp test = {
.obj.orig_dev = br->dev,
@@ -74,6 +75,7 @@ int br_mrp_switchdev_send_ring_test(struct net_bridge *br,
.max_miss = max_miss,
.ring_id = mrp->ring_id,
.period = period,
+ .monitor = monitor,
};
int err;

diff --git a/net/bridge/br_private_mrp.h b/net/bridge/br_private_mrp.h
index 558941ce23669..33b255e38ffec 100644
--- a/net/bridge/br_private_mrp.h
+++ b/net/bridge/br_private_mrp.h
@@ -26,6 +26,7 @@ struct br_mrp {
unsigned long test_end;
u32 test_count_miss;
u32 test_max_miss;
+ bool test_monitor;

u32 seq_id;

@@ -52,7 +53,8 @@ int br_mrp_switchdev_set_ring_role(struct net_bridge *br, struct br_mrp *mrp,
int br_mrp_switchdev_set_ring_state(struct net_bridge *br, struct br_mrp *mrp,
enum br_mrp_ring_state_type state);
int br_mrp_switchdev_send_ring_test(struct net_bridge *br, struct br_mrp *mrp,
- u32 interval, u8 max_miss, u32 period);
+ u32 interval, u8 max_miss, u32 period,
+ bool monitor);
int br_mrp_port_switchdev_set_state(struct net_bridge_port *p,
enum br_mrp_port_state_type state);
int br_mrp_port_switchdev_set_role(struct net_bridge_port *p,
--
2.26.2