bridge: cfm: Kernel space implementation of CFM. CCM frame TX added.

This is the second commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

Functionality is extended with CCM frame transmission.

Interface is extended with these functions:
br_cfm_cc_rdi_set()
br_cfm_cc_ccm_tx()
br_cfm_cc_config_set()

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check parameters can be configured to be used when
    transmitting CCM.

A MEP can be configured to start or stop transmission of CCM frames by
br_cfm_cc_ccm_tx()
    The CCM will be transmitted for a selected period in seconds.
    Must call this function before timeout to keep transmission alive.

A MEP transmitting CCM can be configured with inserted RDI in PDU by
br_cfm_cc_rdi_set()

Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 285 insertions, 0 deletions

diff --git a/net/bridge/br_cfm.c b/net/bridge/br_cfm.c
index 42f35109681a..382e003f5b92 100644
--- a/net/bridge/br_cfm.c
+++ b/net/bridge/br_cfm.c
@@ -53,6 +53,185 @@ static struct net_bridge_port *br_mep_get_port(struct net_bridge *br,
 	return NULL;
 }
 
+/* Calculate the CCM interval in us. */
+static u32 interval_to_us(enum br_cfm_ccm_interval interval)
+{
+	switch (interval) {
+	case BR_CFM_CCM_INTERVAL_NONE:
+		return 0;
+	case BR_CFM_CCM_INTERVAL_3_3_MS:
+		return 3300;
+	case BR_CFM_CCM_INTERVAL_10_MS:
+		return 10 * 1000;
+	case BR_CFM_CCM_INTERVAL_100_MS:
+		return 100 * 1000;
+	case BR_CFM_CCM_INTERVAL_1_SEC:
+		return 1000 * 1000;
+	case BR_CFM_CCM_INTERVAL_10_SEC:
+		return 10 * 1000 * 1000;
+	case BR_CFM_CCM_INTERVAL_1_MIN:
+		return 60 * 1000 * 1000;
+	case BR_CFM_CCM_INTERVAL_10_MIN:
+		return 10 * 60 * 1000 * 1000;
+	}
+	return 0;
+}
+
+/* Convert the interface interval to CCM PDU value. */
+static u32 interval_to_pdu(enum br_cfm_ccm_interval interval)
+{
+	switch (interval) {
+	case BR_CFM_CCM_INTERVAL_NONE:
+		return 0;
+	case BR_CFM_CCM_INTERVAL_3_3_MS:
+		return 1;
+	case BR_CFM_CCM_INTERVAL_10_MS:
+		return 2;
+	case BR_CFM_CCM_INTERVAL_100_MS:
+		return 3;
+	case BR_CFM_CCM_INTERVAL_1_SEC:
+		return 4;
+	case BR_CFM_CCM_INTERVAL_10_SEC:
+		return 5;
+	case BR_CFM_CCM_INTERVAL_1_MIN:
+		return 6;
+	case BR_CFM_CCM_INTERVAL_10_MIN:
+		return 7;
+	}
+	return 0;
+}
+
+static struct sk_buff *ccm_frame_build(struct br_cfm_mep *mep,
+				       const struct br_cfm_cc_ccm_tx_info *const tx_info)
+
+{
+	struct br_cfm_common_hdr *common_hdr;
+	struct net_bridge_port *b_port;
+	struct br_cfm_maid *maid;
+	u8 *itu_reserved, *e_tlv;
+	struct ethhdr *eth_hdr;
+	struct sk_buff *skb;
+	__be32 *status_tlv;
+	__be32 *snumber;
+	__be16 *mepid;
+
+	skb = dev_alloc_skb(CFM_CCM_MAX_FRAME_LENGTH);
+	if (!skb)
+		return NULL;
+
+	rcu_read_lock();
+	b_port = rcu_dereference(mep->b_port);
+	if (!b_port) {
+		kfree_skb(skb);
+		rcu_read_unlock();
+		return NULL;
+	}
+	skb->dev = b_port->dev;
+	rcu_read_unlock();
+	/* The device cannot be deleted until the work_queue functions has
+	 * completed. This function is called from ccm_tx_work_expired()
+	 * that is a work_queue functions.
+	 */
+
+	skb->protocol = htons(ETH_P_CFM);
+	skb->priority = CFM_FRAME_PRIO;
+
+	/* Ethernet header */
+	eth_hdr = skb_put(skb, sizeof(*eth_hdr));
+	ether_addr_copy(eth_hdr->h_dest, tx_info->dmac.addr);
+	ether_addr_copy(eth_hdr->h_source, mep->config.unicast_mac.addr);
+	eth_hdr->h_proto = htons(ETH_P_CFM);
+
+	/* Common CFM Header */
+	common_hdr = skb_put(skb, sizeof(*common_hdr));
+	common_hdr->mdlevel_version = mep->config.mdlevel << 5;
+	common_hdr->opcode = BR_CFM_OPCODE_CCM;
+	common_hdr->flags = (mep->rdi << 7) |
+			    interval_to_pdu(mep->cc_config.exp_interval);
+	common_hdr->tlv_offset = CFM_CCM_TLV_OFFSET;
+
+	/* Sequence number */
+	snumber = skb_put(skb, sizeof(*snumber));
+	if (tx_info->seq_no_update) {
+		*snumber = cpu_to_be32(mep->ccm_tx_snumber);
+		mep->ccm_tx_snumber += 1;
+	} else {
+		*snumber = 0;
+	}
+
+	mepid = skb_put(skb, sizeof(*mepid));
+	*mepid = cpu_to_be16((u16)mep->config.mepid);
+
+	maid = skb_put(skb, sizeof(*maid));
+	memcpy(maid->data, mep->cc_config.exp_maid.data, sizeof(maid->data));
+
+	/* ITU reserved (CFM_CCM_ITU_RESERVED_SIZE octets) */
+	itu_reserved = skb_put(skb, CFM_CCM_ITU_RESERVED_SIZE);
+	memset(itu_reserved, 0, CFM_CCM_ITU_RESERVED_SIZE);
+
+	/* Generel CFM TLV format:
+	 * TLV type:		one byte
+	 * TLV value length:	two bytes
+	 * TLV value:		'TLV value length' bytes
+	 */
+
+	/* Port status TLV. The value length is 1. Total of 4 bytes. */
+	if (tx_info->port_tlv) {
+		status_tlv = skb_put(skb, sizeof(*status_tlv));
+		*status_tlv = cpu_to_be32((CFM_PORT_STATUS_TLV_TYPE << 24) |
+					  (1 << 8) |	/* Value length */
+					  (tx_info->port_tlv_value & 0xFF));
+	}
+
+	/* Interface status TLV. The value length is 1. Total of 4 bytes. */
+	if (tx_info->if_tlv) {
+		status_tlv = skb_put(skb, sizeof(*status_tlv));
+		*status_tlv = cpu_to_be32((CFM_IF_STATUS_TLV_TYPE << 24) |
+					  (1 << 8) |	/* Value length */
+					  (tx_info->if_tlv_value & 0xFF));
+	}
+
+	/* End TLV */
+	e_tlv = skb_put(skb, sizeof(*e_tlv));
+	*e_tlv = CFM_ENDE_TLV_TYPE;
+
+	return skb;
+}
+
+static void ccm_frame_tx(struct sk_buff *skb)
+{
+	skb_reset_network_header(skb);
+	dev_queue_xmit(skb);
+}
+
+/* This function is called with the configured CC 'expected_interval'
+ * in order to drive CCM transmission when enabled.
+ */
+static void ccm_tx_work_expired(struct work_struct *work)
+{
+	struct delayed_work *del_work;
+	struct br_cfm_mep *mep;
+	struct sk_buff *skb;
+	u32 interval_us;
+
+	del_work = to_delayed_work(work);
+	mep = container_of(del_work, struct br_cfm_mep, ccm_tx_dwork);
+
+	if (time_before_eq(mep->ccm_tx_end, jiffies)) {
+		/* Transmission period has ended */
+		mep->cc_ccm_tx_info.period = 0;
+		return;
+	}
+
+	skb = ccm_frame_build(mep, &mep->cc_ccm_tx_info);
+	if (skb)
+		ccm_frame_tx(skb);
+
+	interval_us = interval_to_us(mep->cc_config.exp_interval);
+	queue_delayed_work(system_wq, &mep->ccm_tx_dwork,
+			   usecs_to_jiffies(interval_us));
+}
+
 int br_cfm_mep_create(struct net_bridge *br,
 		      const u32 instance,
 		      struct br_cfm_mep_create *const create,
@@ -115,6 +294,7 @@ int br_cfm_mep_create(struct net_bridge *br,
 	rcu_assign_pointer(mep->b_port, p);
 
 	INIT_HLIST_HEAD(&mep->peer_mep_list);
+	INIT_DELAYED_WORK(&mep->ccm_tx_dwork, ccm_tx_work_expired);
 
 	hlist_add_tail_rcu(&mep->head, &br->mep_list);
 
@@ -135,6 +315,8 @@ static void mep_delete_implementation(struct net_bridge *br,
 		kfree_rcu(peer_mep, rcu);
 	}
 
+	cancel_delayed_work_sync(&mep->ccm_tx_dwork);
+
 	RCU_INIT_POINTER(mep->b_port, NULL);
 	hlist_del_rcu(&mep->head);
 	kfree_rcu(mep, rcu);
@@ -181,6 +363,32 @@ int br_cfm_mep_config_set(struct net_bridge *br,
 	return 0;
 }
 
+int br_cfm_cc_config_set(struct net_bridge *br,
+			 const u32 instance,
+			 const struct br_cfm_cc_config *const config,
+			 struct netlink_ext_ack *extack)
+{
+	struct br_cfm_mep *mep;
+
+	ASSERT_RTNL();
+
+	mep = br_mep_find(br, instance);
+	if (!mep) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "MEP instance does not exists");
+		return -ENOENT;
+	}
+
+	/* Check for no change in configuration */
+	if (memcmp(config, &mep->cc_config, sizeof(*config)) == 0)
+		return 0;
+
+	mep->cc_config = *config;
+	mep->ccm_tx_snumber = 1;
+
+	return 0;
+}
+
 int br_cfm_cc_peer_mep_add(struct net_bridge *br, const u32 instance,
 			   u32 mepid,
 			   struct netlink_ext_ack *extack)
@@ -245,6 +453,83 @@ int br_cfm_cc_peer_mep_remove(struct net_bridge *br, const u32 instance,
 	return 0;
 }
 
+int br_cfm_cc_rdi_set(struct net_bridge *br, const u32 instance,
+		      const bool rdi, struct netlink_ext_ack *extack)
+{
+	struct br_cfm_mep *mep;
+
+	ASSERT_RTNL();
+
+	mep = br_mep_find(br, instance);
+	if (!mep) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "MEP instance does not exists");
+		return -ENOENT;
+	}
+
+	mep->rdi = rdi;
+
+	return 0;
+}
+
+int br_cfm_cc_ccm_tx(struct net_bridge *br, const u32 instance,
+		     const struct br_cfm_cc_ccm_tx_info *const tx_info,
+		     struct netlink_ext_ack *extack)
+{
+	struct br_cfm_mep *mep;
+
+	ASSERT_RTNL();
+
+	mep = br_mep_find(br, instance);
+	if (!mep) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "MEP instance does not exists");
+		return -ENOENT;
+	}
+
+	if (memcmp(tx_info, &mep->cc_ccm_tx_info, sizeof(*tx_info)) == 0) {
+		/* No change in tx_info. */
+		if (mep->cc_ccm_tx_info.period == 0)
+			/* Transmission is not enabled - just return */
+			return 0;
+
+		/* Transmission is ongoing, the end time is recalculated */
+		mep->ccm_tx_end = jiffies +
+				  usecs_to_jiffies(tx_info->period * 1000000);
+		return 0;
+	}
+
+	if (tx_info->period == 0 && mep->cc_ccm_tx_info.period == 0)
+		/* Some change in info and transmission is not ongoing */
+		goto save;
+
+	if (tx_info->period != 0 && mep->cc_ccm_tx_info.period != 0) {
+		/* Some change in info and transmission is ongoing
+		 * The end time is recalculated
+		 */
+		mep->ccm_tx_end = jiffies +
+				  usecs_to_jiffies(tx_info->period * 1000000);
+
+		goto save;
+	}
+
+	if (tx_info->period == 0 && mep->cc_ccm_tx_info.period != 0) {
+		cancel_delayed_work_sync(&mep->ccm_tx_dwork);
+		goto save;
+	}
+
+	/* Start delayed work to transmit CCM frames. It is done with zero delay
+	 * to send first frame immediately
+	 */
+	mep->ccm_tx_end = jiffies + usecs_to_jiffies(tx_info->period * 1000000);
+	queue_delayed_work(system_wq, &mep->ccm_tx_dwork, 0);
+
+save:
+	mep->cc_ccm_tx_info = *tx_info;
+
+	return 0;
+}
+
 /* Deletes the CFM instances on a specific bridge port
  */
 void br_cfm_port_del(struct net_bridge *br, struct net_bridge_port *port)