path: root/net/bridge/br_cfm.c

// 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;
}

/* 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,
		      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);
	INIT_DELAYED_WORK(&mep->ccm_tx_dwork, ccm_tx_work_expired);

	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);
	}

	cancel_delayed_work_sync(&mep->ccm_tx_dwork);

	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_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)
{
	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;
}

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)
{
	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);
}