// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/mrp_bridge.h>
#include "br_private_mrp.h"

static const u8 mrp_test_dmac[ETH_ALEN] = { 0x1, 0x15, 0x4e, 0x0, 0x0, 0x1 };
static const u8 mrp_in_test_dmac[ETH_ALEN] = { 0x1, 0x15, 0x4e, 0x0, 0x0, 0x3 };

static int br_mrp_process(struct net_bridge_port *p, struct sk_buff *skb);

static struct br_frame_type mrp_frame_type __read_mostly = {
        .type = cpu_to_be16(ETH_P_MRP),
        .frame_handler = br_mrp_process,
};

static bool br_mrp_is_ring_port(struct net_bridge_port *p_port,
                                struct net_bridge_port *s_port,
                                struct net_bridge_port *port)
{
        if (port == p_port ||
            port == s_port)
                return true;

        return false;
}

static bool br_mrp_is_in_port(struct net_bridge_port *i_port,
                              struct net_bridge_port *port)
{
        if (port == i_port)
                return true;

        return false;
}

static struct net_bridge_port *br_mrp_get_port(struct net_bridge *br,
                                               u32 ifindex)
{
        struct net_bridge_port *res = NULL;
        struct net_bridge_port *port;

        list_for_each_entry(port, &br->port_list, list) {
                if (port->dev->ifindex == ifindex) {
                        res = port;
                        break;
                }
        }

        return res;
}

static struct br_mrp *br_mrp_find_id(struct net_bridge *br, u32 ring_id)
{
        struct br_mrp *res = NULL;
        struct br_mrp *mrp;

        hlist_for_each_entry_rcu(mrp, &br->mrp_list, list,
                                 lockdep_rtnl_is_held()) {
                if (mrp->ring_id == ring_id) {
                        res = mrp;
                        break;
                }
        }

        return res;
}

static struct br_mrp *br_mrp_find_in_id(struct net_bridge *br, u32 in_id)
{
        struct br_mrp *res = NULL;
        struct br_mrp *mrp;

        hlist_for_each_entry_rcu(mrp, &br->mrp_list, list,
                                 lockdep_rtnl_is_held()) {
                if (mrp->in_id == in_id) {
                        res = mrp;
                        break;
                }
        }

        return res;
}

static bool br_mrp_unique_ifindex(struct net_bridge *br, u32 ifindex)
{
        struct br_mrp *mrp;

        hlist_for_each_entry_rcu(mrp, &br->mrp_list, list,
                                 lockdep_rtnl_is_held()) {
                struct net_bridge_port *p;

                p = rtnl_dereference(mrp->p_port);
                if (p && p->dev->ifindex == ifindex)
                        return false;

                p = rtnl_dereference(mrp->s_port);
                if (p && p->dev->ifindex == ifindex)
                        return false;

                p = rtnl_dereference(mrp->i_port);
                if (p && p->dev->ifindex == ifindex)
                        return false;
        }

        return true;
}

static struct br_mrp *br_mrp_find_port(struct net_bridge *br,
                                       struct net_bridge_port *p)
{
        struct br_mrp *res = NULL;
        struct br_mrp *mrp;

        hlist_for_each_entry_rcu(mrp, &br->mrp_list, list,
                                 lockdep_rtnl_is_held()) {
                if (rcu_access_pointer(mrp->p_port) == p ||
                    rcu_access_pointer(mrp->s_port) == p ||
                    rcu_access_pointer(mrp->i_port) == p) {
                        res = mrp;
                        break;
                }
        }

        return res;
}

static int br_mrp_next_seq(struct br_mrp *mrp)
{
        mrp->seq_id++;
        return mrp->seq_id;
}

static struct sk_buff *br_mrp_skb_alloc(struct net_bridge_port *p,
                                        const u8 *src, const u8 *dst)
{
        struct ethhdr *eth_hdr;
        struct sk_buff *skb;
        __be16 *version;

        skb = dev_alloc_skb(MRP_MAX_FRAME_LENGTH);
        if (!skb)
                return NULL;

        skb->dev = p->dev;
        skb->protocol = htons(ETH_P_MRP);
        skb->priority = MRP_FRAME_PRIO;
        skb_reserve(skb, sizeof(*eth_hdr));

        eth_hdr = skb_push(skb, sizeof(*eth_hdr));
        ether_addr_copy(eth_hdr->h_dest, dst);
        ether_addr_copy(eth_hdr->h_source, src);
        eth_hdr->h_proto = htons(ETH_P_MRP);

        version = skb_put(skb, sizeof(*version));
        *version = cpu_to_be16(MRP_VERSION);

        return skb;
}

static void br_mrp_skb_tlv(struct sk_buff *skb,
                           enum br_mrp_tlv_header_type type,
                           u8 length)
{
        struct br_mrp_tlv_hdr *hdr;

        hdr = skb_put(skb, sizeof(*hdr));
        hdr->type = type;
        hdr->length = length;
}

static void br_mrp_skb_common(struct sk_buff *skb, struct br_mrp *mrp)
{
        struct br_mrp_common_hdr *hdr;

        br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_COMMON, sizeof(*hdr));

        hdr = skb_put(skb, sizeof(*hdr));
        hdr->seq_id = cpu_to_be16(br_mrp_next_seq(mrp));
        memset(hdr->domain, 0xff, MRP_DOMAIN_UUID_LENGTH);
}

static struct sk_buff *br_mrp_alloc_test_skb(struct br_mrp *mrp,
                                             struct net_bridge_port *p,
                                             enum br_mrp_port_role_type port_role)
{
        struct br_mrp_ring_test_hdr *hdr = NULL;
        struct sk_buff *skb = NULL;

        if (!p)
                return NULL;

        skb = br_mrp_skb_alloc(p, p->dev->dev_addr, mrp_test_dmac);
        if (!skb)
                return NULL;

        br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_RING_TEST, sizeof(*hdr));
        hdr = skb_put(skb, sizeof(*hdr));

        hdr->prio = cpu_to_be16(mrp->prio);
        ether_addr_copy(hdr->sa, p->br->dev->dev_addr);
        hdr->port_role = cpu_to_be16(port_role);
        hdr->state = cpu_to_be16(mrp->ring_state);
        hdr->transitions = cpu_to_be16(mrp->ring_transitions);
        hdr->timestamp = cpu_to_be32(jiffies_to_msecs(jiffies));

        br_mrp_skb_common(skb, mrp);

        /* In case the node behaves as MRA then the Test frame needs to have
         * an Option TLV which includes eventually a sub-option TLV that has
         * the type AUTO_MGR
         */
        if (mrp->ring_role == BR_MRP_RING_ROLE_MRA) {
                struct br_mrp_sub_option1_hdr *sub_opt = NULL;
                struct br_mrp_tlv_hdr *sub_tlv = NULL;
                struct br_mrp_oui_hdr *oui = NULL;
                u8 length;

                length = sizeof(*sub_opt) + sizeof(*sub_tlv) + sizeof(oui) +
                        MRP_OPT_PADDING;
                br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_OPTION, length);

                oui = skb_put(skb, sizeof(*oui));
                memset(oui, 0x0, sizeof(*oui));
                sub_opt = skb_put(skb, sizeof(*sub_opt));
                memset(sub_opt, 0x0, sizeof(*sub_opt));

                sub_tlv = skb_put(skb, sizeof(*sub_tlv));
                sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;

                /* 32 bit alligment shall be ensured therefore add 2 bytes */
                skb_put(skb, MRP_OPT_PADDING);
        }

        br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_END, 0x0);

        return skb;
}

static struct sk_buff *br_mrp_alloc_in_test_skb(struct br_mrp *mrp,
                                                struct net_bridge_port *p,
                                                enum br_mrp_port_role_type port_role)
{
        struct br_mrp_in_test_hdr *hdr = NULL;
        struct sk_buff *skb = NULL;

        if (!p)
                return NULL;

        skb = br_mrp_skb_alloc(p, p->dev->dev_addr, mrp_in_test_dmac);
        if (!skb)
                return NULL;

        br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_IN_TEST, sizeof(*hdr));
        hdr = skb_put(skb, sizeof(*hdr));

        hdr->id = cpu_to_be16(mrp->in_id);
        ether_addr_copy(hdr->sa, p->br->dev->dev_addr);
        hdr->port_role = cpu_to_be16(port_role);
        hdr->state = cpu_to_be16(mrp->in_state);
        hdr->transitions = cpu_to_be16(mrp->in_transitions);
        hdr->timestamp = cpu_to_be32(jiffies_to_msecs(jiffies));

        br_mrp_skb_common(skb, mrp);
        br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_END, 0x0);

        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);
        struct br_mrp *mrp = container_of(del_work, struct br_mrp, test_work);
        struct net_bridge_port *p;
        bool notify_open = false;
        struct sk_buff *skb;

        if (time_before_eq(mrp->test_end, jiffies))
                return;

        if (mrp->test_count_miss < mrp->test_max_miss) {
                mrp->test_count_miss++;
        } else {
                /* 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 ||
                    mrp->test_monitor)
                        notify_open = true;
        }

        rcu_read_lock();

        p = rcu_dereference(mrp->p_port);
        if (p) {
                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_ring_port_open(p->dev, true);
        }

        p = rcu_dereference(mrp->s_port);
        if (p) {
                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_ring_port_open(p->dev, true);
        }

out:
        rcu_read_unlock();

        queue_delayed_work(system_wq, &mrp->test_work,
                           usecs_to_jiffies(mrp->test_interval));
}

/* This function is continuously called when the node has the interconnect role
 * MIM. It would generate interconnect test frames and will send them on all 3
 * ports. But will also check if it stop receiving interconnect test frames.
 */
static void br_mrp_in_test_work_expired(struct work_struct *work)
{
        struct delayed_work *del_work = to_delayed_work(work);
        struct br_mrp *mrp = container_of(del_work, struct br_mrp, in_test_work);
        struct net_bridge_port *p;
        bool notify_open = false;
        struct sk_buff *skb;

        if (time_before_eq(mrp->in_test_end, jiffies))
                return;

        if (mrp->in_test_count_miss < mrp->in_test_max_miss) {
                mrp->in_test_count_miss++;
        } else {
                /* Notify that the interconnect ring is open only if the
                 * interconnect ring state is closed, otherwise it would
                 * continue to notify at every interval.
                 */
                if (mrp->in_state == BR_MRP_IN_STATE_CLOSED)
                        notify_open = true;
        }

        rcu_read_lock();

        p = rcu_dereference(mrp->p_port);
        if (p) {
                skb = br_mrp_alloc_in_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->in_role_offloaded)
                        br_mrp_in_port_open(p->dev, true);
        }

        p = rcu_dereference(mrp->s_port);
        if (p) {
                skb = br_mrp_alloc_in_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->in_role_offloaded)
                        br_mrp_in_port_open(p->dev, true);
        }

        p = rcu_dereference(mrp->i_port);
        if (p) {
                skb = br_mrp_alloc_in_test_skb(mrp, p,
                                               BR_MRP_PORT_ROLE_INTER);
                if (!skb)
                        goto out;

                skb_reset_network_header(skb);
                dev_queue_xmit(skb);

                if (notify_open && !mrp->in_role_offloaded)
                        br_mrp_in_port_open(p->dev, true);
        }

out:
        rcu_read_unlock();

        queue_delayed_work(system_wq, &mrp->in_test_work,
                           usecs_to_jiffies(mrp->in_test_interval));
}

/* Deletes the MRP instance.
 * note: called under rtnl_lock
 */
static void br_mrp_del_impl(struct net_bridge *br, struct br_mrp *mrp)
{
        struct net_bridge_port *p;
        u8 state;

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

        /* Stop sending MRP_InTest frames if has an interconnect role */
        cancel_delayed_work_sync(&mrp->in_test_work);
        br_mrp_switchdev_send_in_test(br, mrp, 0, 0, 0);

        /* Disable the roles */
        br_mrp_switchdev_set_ring_role(br, mrp, BR_MRP_RING_ROLE_DISABLED);
        p = rtnl_dereference(mrp->i_port);
        if (p)
                br_mrp_switchdev_set_in_role(br, mrp, mrp->in_id, mrp->ring_id,
                                             BR_MRP_IN_ROLE_DISABLED);

        br_mrp_switchdev_del(br, mrp);

        /* Reset the ports */
        p = rtnl_dereference(mrp->p_port);
        if (p) {
                spin_lock_bh(&br->lock);
                state = netif_running(br->dev) ?
                                BR_STATE_FORWARDING : BR_STATE_DISABLED;
                p->state = state;
                p->flags &= ~BR_MRP_AWARE;
                spin_unlock_bh(&br->lock);
                br_mrp_port_switchdev_set_state(p, state);
                rcu_assign_pointer(mrp->p_port, NULL);
        }

        p = rtnl_dereference(mrp->s_port);
        if (p) {
                spin_lock_bh(&br->lock);
                state = netif_running(br->dev) ?
                                BR_STATE_FORWARDING : BR_STATE_DISABLED;
                p->state = state;
                p->flags &= ~BR_MRP_AWARE;
                spin_unlock_bh(&br->lock);
                br_mrp_port_switchdev_set_state(p, state);
                rcu_assign_pointer(mrp->s_port, NULL);
        }

        p = rtnl_dereference(mrp->i_port);
        if (p) {
                spin_lock_bh(&br->lock);
                state = netif_running(br->dev) ?
                                BR_STATE_FORWARDING : BR_STATE_DISABLED;
                p->state = state;
                p->flags &= ~BR_MRP_AWARE;
                spin_unlock_bh(&br->lock);
                br_mrp_port_switchdev_set_state(p, state);
                rcu_assign_pointer(mrp->i_port, NULL);
        }

        hlist_del_rcu(&mrp->list);
        kfree_rcu(mrp, rcu);

        if (hlist_empty(&br->mrp_list))
                br_del_frame(br, &mrp_frame_type);
}

/* Adds a new MRP instance.
 * note: called under rtnl_lock
 */
int br_mrp_add(struct net_bridge *br, struct br_mrp_instance *instance)
{
        struct net_bridge_port *p;
        struct br_mrp *mrp;
        int err;

        /* If the ring exists, it is not possible to create another one with the
         * same ring_id
         */
        mrp = br_mrp_find_id(br, instance->ring_id);
        if (mrp)
                return -EINVAL;

        if (!br_mrp_get_port(br, instance->p_ifindex) ||
            !br_mrp_get_port(br, instance->s_ifindex))
                return -EINVAL;

        /* It is not possible to have the same port part of multiple rings */
        if (!br_mrp_unique_ifindex(br, instance->p_ifindex) ||
            !br_mrp_unique_ifindex(br, instance->s_ifindex))
                return -EINVAL;

        mrp = kzalloc(sizeof(*mrp), GFP_KERNEL);
        if (!mrp)
                return -ENOMEM;

        mrp->ring_id = instance->ring_id;
        mrp->prio = instance->prio;

        p = br_mrp_get_port(br, instance->p_ifindex);
        spin_lock_bh(&br->lock);
        p->state = BR_STATE_FORWARDING;
        p->flags |= BR_MRP_AWARE;
        spin_unlock_bh(&br->lock);
        rcu_assign_pointer(mrp->p_port, p);

        p = br_mrp_get_port(br, instance->s_ifindex);
        spin_lock_bh(&br->lock);
        p->state = BR_STATE_FORWARDING;
        p->flags |= BR_MRP_AWARE;
        spin_unlock_bh(&br->lock);
        rcu_assign_pointer(mrp->s_port, p);

        if (hlist_empty(&br->mrp_list))
                br_add_frame(br, &mrp_frame_type);

        INIT_DELAYED_WORK(&mrp->test_work, br_mrp_test_work_expired);
        INIT_DELAYED_WORK(&mrp->in_test_work, br_mrp_in_test_work_expired);
        hlist_add_tail_rcu(&mrp->list, &br->mrp_list);

        err = br_mrp_switchdev_add(br, mrp);
        if (err)
                goto delete_mrp;

        return 0;

delete_mrp:
        br_mrp_del_impl(br, mrp);

        return err;
}

/* Deletes the MRP instance from which the port is part of
 * note: called under rtnl_lock
 */
void br_mrp_port_del(struct net_bridge *br, struct net_bridge_port *p)
{
        struct br_mrp *mrp = br_mrp_find_port(br, p);

        /* If the port is not part of a MRP instance just bail out */
        if (!mrp)
                return;

        br_mrp_del_impl(br, mrp);
}

/* Deletes existing MRP instance based on ring_id
 * note: called under rtnl_lock
 */
int br_mrp_del(struct net_bridge *br, struct br_mrp_instance *instance)
{
        struct br_mrp *mrp = br_mrp_find_id(br, instance->ring_id);

        if (!mrp)
                return -EINVAL;

        br_mrp_del_impl(br, mrp);

        return 0;
}

/* Set port state, port state can be forwarding, blocked or disabled
 * note: already called with rtnl_lock
 */
int br_mrp_set_port_state(struct net_bridge_port *p,
                          enum br_mrp_port_state_type state)
{
        u32 port_state;

        if (!p || !(p->flags & BR_MRP_AWARE))
                return -EINVAL;

        spin_lock_bh(&p->br->lock);

        if (state == BR_MRP_PORT_STATE_FORWARDING)
                port_state = BR_STATE_FORWARDING;
        else
                port_state = BR_STATE_BLOCKING;

        p->state = port_state;
        spin_unlock_bh(&p->br->lock);

        br_mrp_port_switchdev_set_state(p, port_state);

        return 0;
}

/* Set port role, port role can be primary or secondary
 * note: already called with rtnl_lock
 */
int br_mrp_set_port_role(struct net_bridge_port *p,
                         enum br_mrp_port_role_type role)
{
        struct br_mrp *mrp;

        if (!p || !(p->flags & BR_MRP_AWARE))
                return -EINVAL;

        mrp = br_mrp_find_port(p->br, p);

        if (!mrp)
                return -EINVAL;

        switch (role) {
        case BR_MRP_PORT_ROLE_PRIMARY:
                rcu_assign_pointer(mrp->p_port, p);
                break;
        case BR_MRP_PORT_ROLE_SECONDARY:
                rcu_assign_pointer(mrp->s_port, p);
                break;
        default:
                return -EINVAL;
        }

        br_mrp_port_switchdev_set_role(p, role);

        return 0;
}

/* Set ring state, ring state can be only Open or Closed
 * note: already called with rtnl_lock
 */
int br_mrp_set_ring_state(struct net_bridge *br,
                          struct br_mrp_ring_state *state)
{
        struct br_mrp *mrp = br_mrp_find_id(br, state->ring_id);

        if (!mrp)
                return -EINVAL;

        if (mrp->ring_state != state->ring_state)
                mrp->ring_transitions++;

        mrp->ring_state = state->ring_state;

        br_mrp_switchdev_set_ring_state(br, mrp, state->ring_state);

        return 0;
}

/* Set ring role, ring role can be only MRM(Media Redundancy Manager) or
 * MRC(Media Redundancy Client).
 * note: already called with rtnl_lock
 */
int br_mrp_set_ring_role(struct net_bridge *br,
                         struct br_mrp_ring_role *role)
{
        struct br_mrp *mrp = br_mrp_find_id(br, role->ring_id);
        enum br_mrp_hw_support support;

        if (!mrp)
                return -EINVAL;

        mrp->ring_role = role->ring_role;

        /* If there is an error just bailed out */
        support = br_mrp_switchdev_set_ring_role(br, mrp, role->ring_role);
        if (support == BR_MRP_NONE)
                return -EOPNOTSUPP;

        /* Now detect if the HW actually applied the role or not. If the HW
         * applied the role it means that the SW will not to do those operations
         * anymore. For example if the role ir MRM then the HW will notify the
         * SW when ring is open, but if the is not pushed to the HW the SW will
         * need to detect when the ring is open
         */
        mrp->ring_role_offloaded = support == BR_MRP_SW ? 0 : 1;

        return 0;
}

/* 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,
                      struct br_mrp_start_test *test)
{
        struct br_mrp *mrp = br_mrp_find_id(br, test->ring_id);
        enum br_mrp_hw_support support;

        if (!mrp)
                return -EINVAL;

        /* Try to push it to the HW and if it fails then continue with SW
         * implementation and if that also fails then return error.
         */
        support = br_mrp_switchdev_send_ring_test(br, mrp, test->interval,
                                                  test->max_miss, test->period,
                                                  test->monitor);
        if (support == BR_MRP_NONE)
                return -EOPNOTSUPP;

        if (support == BR_MRP_HW)
                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));

        return 0;
}

/* Set in state, int state can be only Open or Closed
 * note: already called with rtnl_lock
 */
int br_mrp_set_in_state(struct net_bridge *br, struct br_mrp_in_state *state)
{
        struct br_mrp *mrp = br_mrp_find_in_id(br, state->in_id);

        if (!mrp)
                return -EINVAL;

        if (mrp->in_state != state->in_state)
                mrp->in_transitions++;

        mrp->in_state = state->in_state;

        br_mrp_switchdev_set_in_state(br, mrp, state->in_state);

        return 0;
}

/* Set in role, in role can be only MIM(Media Interconnection Manager) or
 * MIC(Media Interconnection Client).
 * note: already called with rtnl_lock
 */
int br_mrp_set_in_role(struct net_bridge *br, struct br_mrp_in_role *role)
{
        struct br_mrp *mrp = br_mrp_find_id(br, role->ring_id);
        enum br_mrp_hw_support support;
        struct net_bridge_port *p;

        if (!mrp)
                return -EINVAL;

        if (!br_mrp_get_port(br, role->i_ifindex))
                return -EINVAL;

        if (role->in_role == BR_MRP_IN_ROLE_DISABLED) {
                u8 state;

                /* It is not allowed to disable a port that doesn't exist */
                p = rtnl_dereference(mrp->i_port);
                if (!p)
                        return -EINVAL;

                /* Stop the generating MRP_InTest frames */
                cancel_delayed_work_sync(&mrp->in_test_work);
                br_mrp_switchdev_send_in_test(br, mrp, 0, 0, 0);

                /* Remove the port */
                spin_lock_bh(&br->lock);
                state = netif_running(br->dev) ?
                                BR_STATE_FORWARDING : BR_STATE_DISABLED;
                p->state = state;
                p->flags &= ~BR_MRP_AWARE;
                spin_unlock_bh(&br->lock);
                br_mrp_port_switchdev_set_state(p, state);
                rcu_assign_pointer(mrp->i_port, NULL);

                mrp->in_role = role->in_role;
                mrp->in_id = 0;

                return 0;
        }

        /* It is not possible to have the same port part of multiple rings */
        if (!br_mrp_unique_ifindex(br, role->i_ifindex))
                return -EINVAL;

        /* It is not allowed to set a different interconnect port if the mrp
         * instance has already one. First it needs to be disabled and after
         * that set the new port
         */
        if (rcu_access_pointer(mrp->i_port))
                return -EINVAL;

        p = br_mrp_get_port(br, role->i_ifindex);
        spin_lock_bh(&br->lock);
        p->state = BR_STATE_FORWARDING;
        p->flags |= BR_MRP_AWARE;
        spin_unlock_bh(&br->lock);
        rcu_assign_pointer(mrp->i_port, p);

        mrp->in_role = role->in_role;
        mrp->in_id = role->in_id;

        /* If there is an error just bailed out */
        support = br_mrp_switchdev_set_in_role(br, mrp, role->in_id,
                                               role->ring_id, role->in_role);
        if (support == BR_MRP_NONE)
                return -EOPNOTSUPP;

        /* Now detect if the HW actually applied the role or not. If the HW
         * applied the role it means that the SW will not to do those operations
         * anymore. For example if the role is MIM then the HW will notify the
         * SW when interconnect ring is open, but if the is not pushed to the HW
         * the SW will need to detect when the interconnect ring is open.
         */
        mrp->in_role_offloaded = support == BR_MRP_SW ? 0 : 1;

        return 0;
}

/* Start to generate MRP_InTest 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_in_test(struct net_bridge *br,
                         struct br_mrp_start_in_test *in_test)
{
        struct br_mrp *mrp = br_mrp_find_in_id(br, in_test->in_id);
        enum br_mrp_hw_support support;

        if (!mrp)
                return -EINVAL;

        if (mrp->in_role != BR_MRP_IN_ROLE_MIM)
                return -EINVAL;

        /* Try to push it to the HW and if it fails then continue with SW
         * implementation and if that also fails then return error.
         */
        support =  br_mrp_switchdev_send_in_test(br, mrp, in_test->interval,
                                                 in_test->max_miss,
                                                 in_test->period);
        if (support == BR_MRP_NONE)
                return -EOPNOTSUPP;

        if (support == BR_MRP_HW)
                return 0;

        mrp->in_test_interval = in_test->interval;
        mrp->in_test_end = jiffies + usecs_to_jiffies(in_test->period);
        mrp->in_test_max_miss = in_test->max_miss;
        mrp->in_test_count_miss = 0;
        queue_delayed_work(system_wq, &mrp->in_test_work,
                           usecs_to_jiffies(in_test->interval));

        return 0;
}

/* Determine if the frame type is a ring frame */
static bool br_mrp_ring_frame(struct sk_buff *skb)
{
        const struct br_mrp_tlv_hdr *hdr;
        struct br_mrp_tlv_hdr _hdr;

        hdr = skb_header_pointer(skb, sizeof(uint16_t), sizeof(_hdr), &_hdr);
        if (!hdr)
                return false;

        if (hdr->type == BR_MRP_TLV_HEADER_RING_TEST ||
            hdr->type == BR_MRP_TLV_HEADER_RING_TOPO ||
            hdr->type == BR_MRP_TLV_HEADER_RING_LINK_DOWN ||
            hdr->type == BR_MRP_TLV_HEADER_RING_LINK_UP ||
            hdr->type == BR_MRP_TLV_HEADER_OPTION)
                return true;

        return false;
}

/* Determine if the frame type is an interconnect frame */
static bool br_mrp_in_frame(struct sk_buff *skb)
{
        const struct br_mrp_tlv_hdr *hdr;
        struct br_mrp_tlv_hdr _hdr;

        hdr = skb_header_pointer(skb, sizeof(uint16_t), sizeof(_hdr), &_hdr);
        if (!hdr)
                return false;

        if (hdr->type == BR_MRP_TLV_HEADER_IN_TEST ||
            hdr->type == BR_MRP_TLV_HEADER_IN_TOPO ||
            hdr->type == BR_MRP_TLV_HEADER_IN_LINK_DOWN ||
            hdr->type == BR_MRP_TLV_HEADER_IN_LINK_UP ||
            hdr->type == BR_MRP_TLV_HEADER_IN_LINK_STATUS)
                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_mrm_process(struct br_mrp *mrp, struct net_bridge_port *port,
                               struct sk_buff *skb)
{
        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;

        mrp->test_count_miss = 0;

        /* Notify the userspace that the ring is closed only when the ring is
         * not closed
         */
        if (mrp->ring_state != BR_MRP_RING_STATE_CLOSED)
                br_mrp_ring_port_open(port->dev, false);
}

/* Determine 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;
}

/* Process only MRP InTest frame. All the other MRP frames are processed by
 * userspace application
 * note: already called with rcu_read_lock
 */
static bool br_mrp_mim_process(struct br_mrp *mrp, struct net_bridge_port *port,
                               struct sk_buff *skb)
{

        const struct br_mrp_in_test_hdr *in_hdr;
        struct br_mrp_in_test_hdr _in_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 false;

        /* The check for InTest frame type was already done */
        in_hdr = skb_header_pointer(skb, sizeof(uint16_t) + sizeof(_hdr),
                                    sizeof(_in_hdr), &_in_hdr);
        if (!in_hdr)
                return false;

        /* It needs to process only it's own InTest frames. */
        if (mrp->in_id != ntohs(in_hdr->id))
                return false;

        mrp->in_test_count_miss = 0;

        /* Notify the userspace that the ring is closed only when the ring is
         * not closed
         */
        if (mrp->in_state != BR_MRP_IN_STATE_CLOSED)
                br_mrp_in_port_open(port->dev, false);

        return true;
}

/* Get the MRP frame type
 * note: already called with rcu_read_lock
 */
static u8 br_mrp_get_frame_type(struct sk_buff *skb)
{
        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 0xff;

        return hdr->type;
}

static bool br_mrp_mrm_behaviour(struct br_mrp *mrp)
{
        if (mrp->ring_role == BR_MRP_RING_ROLE_MRM ||
            (mrp->ring_role == BR_MRP_RING_ROLE_MRA && !mrp->test_monitor))
                return true;

        return false;
}

static bool br_mrp_mrc_behaviour(struct br_mrp *mrp)
{
        if (mrp->ring_role == BR_MRP_RING_ROLE_MRC ||
            (mrp->ring_role == BR_MRP_RING_ROLE_MRA && mrp->test_monitor))
                return true;

        return false;
}

/* This will just forward the frame to the other mrp ring ports, depending on
 * the frame type, ring role and interconnect role
 * note: already called with rcu_read_lock
 */
static int br_mrp_rcv(struct net_bridge_port *p,
                      struct sk_buff *skb, struct net_device *dev)
{
        struct net_bridge_port *p_port, *s_port, *i_port = NULL;
        struct net_bridge_port *p_dst, *s_dst, *i_dst = NULL;
        struct net_bridge *br;
        struct br_mrp *mrp;

        /* If port is disabled don't accept any frames */
        if (p->state == BR_STATE_DISABLED)
                return 0;

        br = p->br;
        mrp =  br_mrp_find_port(br, p);
        if (unlikely(!mrp))
                return 0;

        p_port = rcu_dereference(mrp->p_port);
        if (!p_port)
                return 0;
        p_dst = p_port;

        s_port = rcu_dereference(mrp->s_port);
        if (!s_port)
                return 0;
        s_dst = s_port;

        /* If the frame is a ring frame then it is not required to check the
         * interconnect role and ports to process or forward the frame
         */
        if (br_mrp_ring_frame(skb)) {
                /* If the role is MRM then don't forward the frames */
                if (mrp->ring_role == BR_MRP_RING_ROLE_MRM) {
                        br_mrp_mrm_process(mrp, p, skb);
                        goto no_forward;
                }

                /* 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);
                                goto no_forward;
                        }

                        br_mrp_mra_process(mrp, br, p, skb);
                }

                goto forward;
        }

        if (br_mrp_in_frame(skb)) {
                u8 in_type = br_mrp_get_frame_type(skb);

                i_port = rcu_dereference(mrp->i_port);
                i_dst = i_port;

                /* If the ring port is in block state it should not forward
                 * In_Test frames
                 */
                if (br_mrp_is_ring_port(p_port, s_port, p) &&
                    p->state == BR_STATE_BLOCKING &&
                    in_type == BR_MRP_TLV_HEADER_IN_TEST)
                        goto no_forward;

                /* Nodes that behaves as MRM needs to stop forwarding the
                 * frames in case the ring is closed, otherwise will be a loop.
                 * In this case the frame is no forward between the ring ports.
                 */
                if (br_mrp_mrm_behaviour(mrp) &&
                    br_mrp_is_ring_port(p_port, s_port, p) &&
                    (s_port->state != BR_STATE_FORWARDING ||
                     p_port->state != BR_STATE_FORWARDING)) {
                        p_dst = NULL;
                        s_dst = NULL;
                }

                /* A node that behaves as MRC and doesn't have a interconnect
                 * role then it should forward all frames between the ring ports
                 * because it doesn't have an interconnect port
                 */
                if (br_mrp_mrc_behaviour(mrp) &&
                    mrp->in_role == BR_MRP_IN_ROLE_DISABLED)
                        goto forward;

                if (mrp->in_role == BR_MRP_IN_ROLE_MIM) {
                        if (in_type == BR_MRP_TLV_HEADER_IN_TEST) {
                                /* MIM should not forward it's own InTest
                                 * frames
                                 */
                                if (br_mrp_mim_process(mrp, p, skb)) {
                                        goto no_forward;
                                } else {
                                        if (br_mrp_is_ring_port(p_port, s_port,
                                                                p))
                                                i_dst = NULL;

                                        if (br_mrp_is_in_port(i_port, p))
                                                goto no_forward;
                                }
                        } else {
                                /* MIM should forward IntLinkChange/Status and
                                 * IntTopoChange between ring ports but MIM
                                 * should not forward IntLinkChange/Status and
                                 * IntTopoChange if the frame was received at
                                 * the interconnect port
                                 */
                                if (br_mrp_is_ring_port(p_port, s_port, p))
                                        i_dst = NULL;

                                if (br_mrp_is_in_port(i_port, p))
                                        goto no_forward;
                        }
                }

                if (mrp->in_role == BR_MRP_IN_ROLE_MIC) {
                        /* MIC should forward InTest frames on all ports
                         * regardless of the received port
                         */
                        if (in_type == BR_MRP_TLV_HEADER_IN_TEST)
                                goto forward;

                        /* MIC should forward IntLinkChange frames only if they
                         * are received on ring ports to all the ports
                         */
                        if (br_mrp_is_ring_port(p_port, s_port, p) &&
                            (in_type == BR_MRP_TLV_HEADER_IN_LINK_UP ||
                             in_type == BR_MRP_TLV_HEADER_IN_LINK_DOWN))
                                goto forward;

                        /* MIC should forward IntLinkStatus frames only to
                         * interconnect port if it was received on a ring port.
                         * If it is received on interconnect port then, it
                         * should be forward on both ring ports
                         */
                        if (br_mrp_is_ring_port(p_port, s_port, p) &&
                            in_type == BR_MRP_TLV_HEADER_IN_LINK_STATUS) {
                                p_dst = NULL;
                                s_dst = NULL;
                        }

                        /* Should forward the InTopo frames only between the
                         * ring ports
                         */
                        if (in_type == BR_MRP_TLV_HEADER_IN_TOPO) {
                                i_dst = NULL;
                                goto forward;
                        }

                        /* In all the other cases don't forward the frames */
                        goto no_forward;
                }
        }

forward:
        if (p_dst)
                br_forward(p_dst, skb, true, false);
        if (s_dst)
                br_forward(s_dst, skb, true, false);
        if (i_dst)
                br_forward(i_dst, skb, true, false);

no_forward:
        return 1;
}

/* Check if the frame was received on a port that is part of MRP ring
 * and if the frame has MRP eth. In that case process the frame otherwise do
 * normal forwarding.
 * note: already called with rcu_read_lock
 */
static int br_mrp_process(struct net_bridge_port *p, struct sk_buff *skb)
{
        /* If there is no MRP instance do normal forwarding */
        if (likely(!(p->flags & BR_MRP_AWARE)))
                goto out;

        return br_mrp_rcv(p, skb, p->dev);
out:
        return 0;
}

bool br_mrp_enabled(struct net_bridge *br)
{
        return !hlist_empty(&br->mrp_list);
}