Commit 86a14b79 authored by Henrik Bjoernlund's avatar Henrik Bjoernlund Committed by Jakub Kicinski
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bridge: cfm: Kernel space implementation of CFM. MEP create/delete. 



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

It contains MEP instance create, delete and configuration.

Connectivity Fault Management (CFM) comprises capabilities for
detecting, verifying, and isolating connectivity failures in
Virtual Bridged Networks. These capabilities can be used in
networks operated by multiple independent organizations, each
with restricted management access to each others equipment.

CFM functions are partitioned as follows:
    - Path discovery
    - Fault detection
    - Fault verification and isolation
    - Fault notification
    - Fault recovery

Interface consists of these functions:
br_cfm_mep_create()
br_cfm_mep_delete()
br_cfm_mep_config_set()
br_cfm_cc_config_set()
br_cfm_cc_peer_mep_add()
br_cfm_cc_peer_mep_remove()

A MEP instance is created by br_cfm_mep_create()
    -It is the Maintenance association End Point
     described in 802.1Q section 19.2.
    -It is created on a specific level (1-7) and is assuring
     that no CFM frames are passing through this MEP on lower levels.
    -It initiates and validates CFM frames on its level.
    -It can only exist on a port that is related to a bridge.
    -Attributes given cannot be changed until the instance is
     deleted.

A MEP instance can be deleted by br_cfm_mep_delete().

A created MEP instance has attributes that can be
configured by br_cfm_mep_config_set().

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check Receiver state machine can be
    enabled and disabled.
    According to 802.1Q section 19.2.8

A MEP can have Peer MEPs added and removed by
br_cfm_cc_peer_mep_add() and br_cfm_cc_peer_mep_remove()
    The Continuity Check feature can maintain connectivity
    status on each added Peer MEP.

Signed-off-by: default avatarHenrik Bjoernlund <henrik.bjoernlund@microchip.com>
Reviewed-by: default avatarHoratiu Vultur <horatiu.vultur@microchip.com>
Acked-by: default avatarNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fbaedb41

include/uapi/linux/cfm_bridge.h

0 → 100644
+23 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */



#ifndef _UAPI_LINUX_CFM_BRIDGE_H_

#define _UAPI_LINUX_CFM_BRIDGE_H_



#include <linux/types.h>

#include <linux/if_ether.h>



#define CFM_MAID_LENGTH		48



/* MEP domain */

enum br_cfm_domain {

	BR_CFM_PORT,

	BR_CFM_VLAN,

};



/* MEP direction */

enum br_cfm_mep_direction {

	BR_CFM_MEP_DIRECTION_DOWN,

	BR_CFM_MEP_DIRECTION_UP,

};



#endif

net/bridge/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -27,3 +27,5 @@ bridge-$(CONFIG_NET_SWITCHDEV) += br_switchdev.o 
obj-$(CONFIG_NETFILTER) += netfilter/



bridge-$(CONFIG_BRIDGE_MRP)	+= br_mrp_switchdev.o br_mrp.o br_mrp_netlink.o



bridge-$(CONFIG_BRIDGE_CFM)	+= br_cfm.o

net/bridge/br_cfm.c

0 → 100644
+260 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later



#include <linux/cfm_bridge.h>

#include <uapi/linux/cfm_bridge.h>

#include "br_private_cfm.h"



static struct br_cfm_mep *br_mep_find(struct net_bridge *br, u32 instance)

{

	struct br_cfm_mep *mep;



	hlist_for_each_entry(mep, &br->mep_list, head)

		if (mep->instance == instance)

			return mep;



	return NULL;

}



static struct br_cfm_mep *br_mep_find_ifindex(struct net_bridge *br,

					      u32 ifindex)

{

	struct br_cfm_mep *mep;



	hlist_for_each_entry_rcu(mep, &br->mep_list, head,

				 lockdep_rtnl_is_held())

		if (mep->create.ifindex == ifindex)

			return mep;



	return NULL;

}



static struct br_cfm_peer_mep *br_peer_mep_find(struct br_cfm_mep *mep,

						u32 mepid)

{

	struct br_cfm_peer_mep *peer_mep;



	hlist_for_each_entry_rcu(peer_mep, &mep->peer_mep_list, head,

				 lockdep_rtnl_is_held())

		if (peer_mep->mepid == mepid)

			return peer_mep;



	return NULL;

}



static struct net_bridge_port *br_mep_get_port(struct net_bridge *br,

					       u32 ifindex)

{

	struct net_bridge_port *port;



	list_for_each_entry(port, &br->port_list, list)

		if (port->dev->ifindex == ifindex)

			return port;



	return NULL;

}



int br_cfm_mep_create(struct net_bridge *br,

		      const u32 instance,

		      struct br_cfm_mep_create *const create,

		      struct netlink_ext_ack *extack)

{

	struct net_bridge_port *p;

	struct br_cfm_mep *mep;



	ASSERT_RTNL();



	if (create->domain == BR_CFM_VLAN) {

		NL_SET_ERR_MSG_MOD(extack,

				   "VLAN domain not supported");

		return -EINVAL;

	}

	if (create->domain != BR_CFM_PORT) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Invalid domain value");

		return -EINVAL;

	}

	if (create->direction == BR_CFM_MEP_DIRECTION_UP) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Up-MEP not supported");

		return -EINVAL;

	}

	if (create->direction != BR_CFM_MEP_DIRECTION_DOWN) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Invalid direction value");

		return -EINVAL;

	}

	p = br_mep_get_port(br, create->ifindex);

	if (!p) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Port is not related to bridge");

		return -EINVAL;

	}

	mep = br_mep_find(br, instance);

	if (mep) {

		NL_SET_ERR_MSG_MOD(extack,

				   "MEP instance already exists");

		return -EEXIST;

	}



	/* In PORT domain only one instance can be created per port */

	if (create->domain == BR_CFM_PORT) {

		mep = br_mep_find_ifindex(br, create->ifindex);

		if (mep) {

			NL_SET_ERR_MSG_MOD(extack,

					   "Only one Port MEP on a port allowed");

			return -EINVAL;

		}

	}



	mep = kzalloc(sizeof(*mep), GFP_KERNEL);

	if (!mep)

		return -ENOMEM;



	mep->create = *create;

	mep->instance = instance;

	rcu_assign_pointer(mep->b_port, p);



	INIT_HLIST_HEAD(&mep->peer_mep_list);



	hlist_add_tail_rcu(&mep->head, &br->mep_list);



	return 0;

}



static void mep_delete_implementation(struct net_bridge *br,

				      struct br_cfm_mep *mep)

{

	struct br_cfm_peer_mep *peer_mep;

	struct hlist_node *n_store;



	ASSERT_RTNL();



	/* Empty and free peer MEP list */

	hlist_for_each_entry_safe(peer_mep, n_store, &mep->peer_mep_list, head) {

		hlist_del_rcu(&peer_mep->head);

		kfree_rcu(peer_mep, rcu);

	}



	RCU_INIT_POINTER(mep->b_port, NULL);

	hlist_del_rcu(&mep->head);

	kfree_rcu(mep, rcu);

}



int br_cfm_mep_delete(struct net_bridge *br,

		      const u32 instance,

		      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_delete_implementation(br, mep);



	return 0;

}



int br_cfm_mep_config_set(struct net_bridge *br,

			  const u32 instance,

			  const struct br_cfm_mep_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;

	}



	mep->config = *config;



	return 0;

}



int br_cfm_cc_peer_mep_add(struct net_bridge *br, const u32 instance,

			   u32 mepid,

			   struct netlink_ext_ack *extack)

{

	struct br_cfm_peer_mep *peer_mep;

	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;

	}



	peer_mep = br_peer_mep_find(mep, mepid);

	if (peer_mep) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Peer MEP-ID already exists");

		return -EEXIST;

	}



	peer_mep = kzalloc(sizeof(*peer_mep), GFP_KERNEL);

	if (!peer_mep)

		return -ENOMEM;



	peer_mep->mepid = mepid;

	peer_mep->mep = mep;



	hlist_add_tail_rcu(&peer_mep->head, &mep->peer_mep_list);



	return 0;

}



int br_cfm_cc_peer_mep_remove(struct net_bridge *br, const u32 instance,

			      u32 mepid,

			      struct netlink_ext_ack *extack)

{

	struct br_cfm_peer_mep *peer_mep;

	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;

	}



	peer_mep = br_peer_mep_find(mep, mepid);

	if (!peer_mep) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Peer MEP-ID does not exists");

		return -ENOENT;

	}



	hlist_del_rcu(&peer_mep->head);

	kfree_rcu(peer_mep, rcu);



	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)

{

	struct hlist_node *n_store;

	struct br_cfm_mep *mep;



	ASSERT_RTNL();



	hlist_for_each_entry_safe(mep, n_store, &br->mep_list, head)

		if (mep->create.ifindex == port->dev->ifindex)

			mep_delete_implementation(br, mep);

}

net/bridge/br_if.c

+1 −0
Original line number Diff line number Diff line
@@ -334,6 +334,7 @@ static void del_nbp(struct net_bridge_port *p) 
	spin_unlock_bh(&br->lock);



	br_mrp_port_del(br, p);

	br_cfm_port_del(br, p);



	br_ifinfo_notify(RTM_DELLINK, NULL, p);

net/bridge/br_private.h

+10 −0
Original line number Diff line number Diff line
@@ -1459,6 +1459,16 @@ static inline int br_mrp_fill_info(struct sk_buff *skb, struct net_bridge *br) 


#endif



/* br_mrp.c */

#if IS_ENABLED(CONFIG_BRIDGE_CFM)

void br_cfm_port_del(struct net_bridge *br, struct net_bridge_port *p);

#else

static inline void br_cfm_port_del(struct net_bridge *br,

				   struct net_bridge_port *p)

{

}

#endif



/* br_netlink.c */

extern struct rtnl_link_ops br_link_ops;

int br_netlink_init(void);

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