/*
 * net/switchdev/switchdev.c - Switch device API
 * Copyright (c) 2014-2015 Jiri Pirko <jiri@resnulli.us>
 * Copyright (c) 2014-2015 Scott Feldman <sfeldma@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_bridge.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <linux/if_vlan.h>
#include <linux/rtnetlink.h>
#include <net/switchdev.h>

/**
 *      switchdev_trans_item_enqueue - Enqueue data item to transaction queue
 *
 *      @trans: transaction
 *      @data: pointer to data being queued
 *      @destructor: data destructor
 *      @tritem: transaction item being queued
 *
 *      Enqeueue data item to transaction queue. tritem is typically placed in
 *      cointainter pointed at by data pointer. Destructor is called on
 *      transaction abort and after successful commit phase in case
 *      the caller did not dequeue the item before.
 */
void switchdev_trans_item_enqueue(struct switchdev_trans *trans,
                                  void *data, void (*destructor)(void const *),
                                  struct switchdev_trans_item *tritem)
{
        tritem->data = data;
        tritem->destructor = destructor;
        list_add_tail(&tritem->list, &trans->item_list);
}
EXPORT_SYMBOL_GPL(switchdev_trans_item_enqueue);

static struct switchdev_trans_item *
__switchdev_trans_item_dequeue(struct switchdev_trans *trans)
{
        struct switchdev_trans_item *tritem;

        if (list_empty(&trans->item_list))
                return NULL;
        tritem = list_first_entry(&trans->item_list,
                                  struct switchdev_trans_item, list);
        list_del(&tritem->list);
        return tritem;
}

/**
 *      switchdev_trans_item_dequeue - Dequeue data item from transaction queue
 *
 *      @trans: transaction
 */
void *switchdev_trans_item_dequeue(struct switchdev_trans *trans)
{
        struct switchdev_trans_item *tritem;

        tritem = __switchdev_trans_item_dequeue(trans);
        BUG_ON(!tritem);
        return tritem->data;
}
EXPORT_SYMBOL_GPL(switchdev_trans_item_dequeue);

static void switchdev_trans_init(struct switchdev_trans *trans)
{
        INIT_LIST_HEAD(&trans->item_list);
}

static void switchdev_trans_items_destroy(struct switchdev_trans *trans)
{
        struct switchdev_trans_item *tritem;

        while ((tritem = __switchdev_trans_item_dequeue(trans)))
                tritem->destructor(tritem->data);
}

static void switchdev_trans_items_warn_destroy(struct net_device *dev,
                                               struct switchdev_trans *trans)
{
        WARN(!list_empty(&trans->item_list), "%s: transaction item queue is not empty.\n",
             dev->name);
        switchdev_trans_items_destroy(trans);
}

static LIST_HEAD(deferred);
static DEFINE_SPINLOCK(deferred_lock);

typedef void switchdev_deferred_func_t(struct net_device *dev,
                                       const void *data);

struct switchdev_deferred_item {
        struct list_head list;
        struct net_device *dev;
        switchdev_deferred_func_t *func;
        unsigned long data[0];
};

static struct switchdev_deferred_item *switchdev_deferred_dequeue(void)
{
        struct switchdev_deferred_item *dfitem;

        spin_lock_bh(&deferred_lock);
        if (list_empty(&deferred)) {
                dfitem = NULL;
                goto unlock;
        }
        dfitem = list_first_entry(&deferred,
                                  struct switchdev_deferred_item, list);
        list_del(&dfitem->list);
unlock:
        spin_unlock_bh(&deferred_lock);
        return dfitem;
}

/**
 *      switchdev_deferred_process - Process ops in deferred queue
 *
 *      Called to flush the ops currently queued in deferred ops queue.
 *      rtnl_lock must be held.
 */
void switchdev_deferred_process(void)
{
        struct switchdev_deferred_item *dfitem;

        ASSERT_RTNL();

        while ((dfitem = switchdev_deferred_dequeue())) {
                dfitem->func(dfitem->dev, dfitem->data);
                dev_put(dfitem->dev);
                kfree(dfitem);
        }
}
EXPORT_SYMBOL_GPL(switchdev_deferred_process);

static void switchdev_deferred_process_work(struct work_struct *work)
{
        rtnl_lock();
        switchdev_deferred_process();
        rtnl_unlock();
}

static DECLARE_WORK(deferred_process_work, switchdev_deferred_process_work);

static int switchdev_deferred_enqueue(struct net_device *dev,
                                      const void *data, size_t data_len,
                                      switchdev_deferred_func_t *func)
{
        struct switchdev_deferred_item *dfitem;

        dfitem = kmalloc(sizeof(*dfitem) + data_len, GFP_ATOMIC);
        if (!dfitem)
                return -ENOMEM;
        dfitem->dev = dev;
        dfitem->func = func;
        memcpy(dfitem->data, data, data_len);
        dev_hold(dev);
        spin_lock_bh(&deferred_lock);
        list_add_tail(&dfitem->list, &deferred);
        spin_unlock_bh(&deferred_lock);
        schedule_work(&deferred_process_work);
        return 0;
}

/**
 *      switchdev_port_attr_get - Get port attribute
 *
 *      @dev: port device
 *      @attr: attribute to get
 */
int switchdev_port_attr_get(struct net_device *dev, struct switchdev_attr *attr)
{
        const struct switchdev_ops *ops = dev->switchdev_ops;
        struct net_device *lower_dev;
        struct list_head *iter;
        struct switchdev_attr first = {
                .id = SWITCHDEV_ATTR_ID_UNDEFINED
        };
        int err = -EOPNOTSUPP;

        if (ops && ops->switchdev_port_attr_get)
                return ops->switchdev_port_attr_get(dev, attr);

        if (attr->flags & SWITCHDEV_F_NO_RECURSE)
                return err;

        /* Switch device port(s) may be stacked under
         * bond/team/vlan dev, so recurse down to get attr on
         * each port.  Return -ENODATA if attr values don't
         * compare across ports.
         */

        netdev_for_each_lower_dev(dev, lower_dev, iter) {
                err = switchdev_port_attr_get(lower_dev, attr);
                if (err)
                        break;
                if (first.id == SWITCHDEV_ATTR_ID_UNDEFINED)
                        first = *attr;
                else if (memcmp(&first, attr, sizeof(*attr)))
                        return -ENODATA;
        }

        return err;
}
EXPORT_SYMBOL_GPL(switchdev_port_attr_get);

static int __switchdev_port_attr_set(struct net_device *dev,
                                     const struct switchdev_attr *attr,
                                     struct switchdev_trans *trans)
{
        const struct switchdev_ops *ops = dev->switchdev_ops;
        struct net_device *lower_dev;
        struct list_head *iter;
        int err = -EOPNOTSUPP;

        if (ops && ops->switchdev_port_attr_set) {
                err = ops->switchdev_port_attr_set(dev, attr, trans);
                goto done;
        }

        if (attr->flags & SWITCHDEV_F_NO_RECURSE)
                goto done;

        /* Switch device port(s) may be stacked under
         * bond/team/vlan dev, so recurse down to set attr on
         * each port.
         */

        netdev_for_each_lower_dev(dev, lower_dev, iter) {
                err = __switchdev_port_attr_set(lower_dev, attr, trans);
                if (err)
                        break;
        }

done:
        if (err == -EOPNOTSUPP && attr->flags & SWITCHDEV_F_SKIP_EOPNOTSUPP)
                err = 0;

        return err;
}

static int switchdev_port_attr_set_now(struct net_device *dev,
                                       const struct switchdev_attr *attr)
{
        struct switchdev_trans trans;
        int err;

        switchdev_trans_init(&trans);

        /* Phase I: prepare for attr set. Driver/device should fail
         * here if there are going to be issues in the commit phase,
         * such as lack of resources or support.  The driver/device
         * should reserve resources needed for the commit phase here,
         * but should not commit the attr.
         */

        trans.ph_prepare = true;
        err = __switchdev_port_attr_set(dev, attr, &trans);
        if (err) {
                /* Prepare phase failed: abort the transaction.  Any
                 * resources reserved in the prepare phase are
                 * released.
                 */

                if (err != -EOPNOTSUPP)
                        switchdev_trans_items_destroy(&trans);

                return err;
        }

        /* Phase II: commit attr set.  This cannot fail as a fault
         * of driver/device.  If it does, it's a bug in the driver/device
         * because the driver said everythings was OK in phase I.
         */

        trans.ph_prepare = false;
        err = __switchdev_port_attr_set(dev, attr, &trans);
        WARN(err, "%s: Commit of attribute (id=%d) failed.\n",
             dev->name, attr->id);
        switchdev_trans_items_warn_destroy(dev, &trans);

        return err;
}

static void switchdev_port_attr_set_deferred(struct net_device *dev,
                                             const void *data)
{
        const struct switchdev_attr *attr = data;
        int err;

        err = switchdev_port_attr_set_now(dev, attr);
        if (err && err != -EOPNOTSUPP)
                netdev_err(dev, "failed (err=%d) to set attribute (id=%d)\n",
                           err, attr->id);
        if (attr->complete)
                attr->complete(dev, err, attr->complete_priv);
}

static int switchdev_port_attr_set_defer(struct net_device *dev,
                                         const struct switchdev_attr *attr)
{
        return switchdev_deferred_enqueue(dev, attr, sizeof(*attr),
                                          switchdev_port_attr_set_deferred);
}

/**
 *      switchdev_port_attr_set - Set port attribute
 *
 *      @dev: port device
 *      @attr: attribute to set
 *
 *      Use a 2-phase prepare-commit transaction model to ensure
 *      system is not left in a partially updated state due to
 *      failure from driver/device.
 *
 *      rtnl_lock must be held and must not be in atomic section,
 *      in case SWITCHDEV_F_DEFER flag is not set.
 */
int switchdev_port_attr_set(struct net_device *dev,
                            const struct switchdev_attr *attr)
{
        if (attr->flags & SWITCHDEV_F_DEFER)
                return switchdev_port_attr_set_defer(dev, attr);
        ASSERT_RTNL();
        return switchdev_port_attr_set_now(dev, attr);
}
EXPORT_SYMBOL_GPL(switchdev_port_attr_set);

static size_t switchdev_obj_size(const struct switchdev_obj *obj)
{
        switch (obj->id) {
        case SWITCHDEV_OBJ_ID_PORT_VLAN:
                return sizeof(struct switchdev_obj_port_vlan);
        case SWITCHDEV_OBJ_ID_PORT_MDB:
                return sizeof(struct switchdev_obj_port_mdb);
        case SWITCHDEV_OBJ_ID_HOST_MDB:
                return sizeof(struct switchdev_obj_port_mdb);
        default:
                BUG();
        }
        return 0;
}

static int __switchdev_port_obj_add(struct net_device *dev,
                                    const struct switchdev_obj *obj,
                                    struct switchdev_trans *trans)
{
        const struct switchdev_ops *ops = dev->switchdev_ops;
        struct net_device *lower_dev;
        struct list_head *iter;
        int err = -EOPNOTSUPP;

        if (ops && ops->switchdev_port_obj_add)
                return ops->switchdev_port_obj_add(dev, obj, trans);

        /* Switch device port(s) may be stacked under
         * bond/team/vlan dev, so recurse down to add object on
         * each port.
         */

        netdev_for_each_lower_dev(dev, lower_dev, iter) {
                err = __switchdev_port_obj_add(lower_dev, obj, trans);
                if (err)
                        break;
        }

        return err;
}

static int switchdev_port_obj_add_now(struct net_device *dev,
                                      const struct switchdev_obj *obj)
{
        struct switchdev_trans trans;
        int err;

        ASSERT_RTNL();

        switchdev_trans_init(&trans);

        /* Phase I: prepare for obj add. Driver/device should fail
         * here if there are going to be issues in the commit phase,
         * such as lack of resources or support.  The driver/device
         * should reserve resources needed for the commit phase here,
         * but should not commit the obj.
         */

        trans.ph_prepare = true;
        err = __switchdev_port_obj_add(dev, obj, &trans);
        if (err) {
                /* Prepare phase failed: abort the transaction.  Any
                 * resources reserved in the prepare phase are
                 * released.
                 */

                if (err != -EOPNOTSUPP)
                        switchdev_trans_items_destroy(&trans);

                return err;
        }

        /* Phase II: commit obj add.  This cannot fail as a fault
         * of driver/device.  If it does, it's a bug in the driver/device
         * because the driver said everythings was OK in phase I.
         */

        trans.ph_prepare = false;
        err = __switchdev_port_obj_add(dev, obj, &trans);
        WARN(err, "%s: Commit of object (id=%d) failed.\n", dev->name, obj->id);
        switchdev_trans_items_warn_destroy(dev, &trans);

        return err;
}

static void switchdev_port_obj_add_deferred(struct net_device *dev,
                                            const void *data)
{
        const struct switchdev_obj *obj = data;
        int err;

        err = switchdev_port_obj_add_now(dev, obj);
        if (err && err != -EOPNOTSUPP)
                netdev_err(dev, "failed (err=%d) to add object (id=%d)\n",
                           err, obj->id);
        if (obj->complete)
                obj->complete(dev, err, obj->complete_priv);
}

static int switchdev_port_obj_add_defer(struct net_device *dev,
                                        const struct switchdev_obj *obj)
{
        return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
                                          switchdev_port_obj_add_deferred);
}

/**
 *      switchdev_port_obj_add - Add port object
 *
 *      @dev: port device
 *      @id: object ID
 *      @obj: object to add
 *
 *      Use a 2-phase prepare-commit transaction model to ensure
 *      system is not left in a partially updated state due to
 *      failure from driver/device.
 *
 *      rtnl_lock must be held and must not be in atomic section,
 *      in case SWITCHDEV_F_DEFER flag is not set.
 */
int switchdev_port_obj_add(struct net_device *dev,
                           const struct switchdev_obj *obj)
{
        if (obj->flags & SWITCHDEV_F_DEFER)
                return switchdev_port_obj_add_defer(dev, obj);
        ASSERT_RTNL();
        return switchdev_port_obj_add_now(dev, obj);
}
EXPORT_SYMBOL_GPL(switchdev_port_obj_add);

static int switchdev_port_obj_del_now(struct net_device *dev,
                                      const struct switchdev_obj *obj)
{
        const struct switchdev_ops *ops = dev->switchdev_ops;
        struct net_device *lower_dev;
        struct list_head *iter;
        int err = -EOPNOTSUPP;

        if (ops && ops->switchdev_port_obj_del)
                return ops->switchdev_port_obj_del(dev, obj);

        /* Switch device port(s) may be stacked under
         * bond/team/vlan dev, so recurse down to delete object on
         * each port.
         */

        netdev_for_each_lower_dev(dev, lower_dev, iter) {
                err = switchdev_port_obj_del_now(lower_dev, obj);
                if (err)
                        break;
        }

        return err;
}

static void switchdev_port_obj_del_deferred(struct net_device *dev,
                                            const void *data)
{
        const struct switchdev_obj *obj = data;
        int err;

        err = switchdev_port_obj_del_now(dev, obj);
        if (err && err != -EOPNOTSUPP)
                netdev_err(dev, "failed (err=%d) to del object (id=%d)\n",
                           err, obj->id);
        if (obj->complete)
                obj->complete(dev, err, obj->complete_priv);
}

static int switchdev_port_obj_del_defer(struct net_device *dev,
                                        const struct switchdev_obj *obj)
{
        return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
                                          switchdev_port_obj_del_deferred);
}

/**
 *      switchdev_port_obj_del - Delete port object
 *
 *      @dev: port device
 *      @id: object ID
 *      @obj: object to delete
 *
 *      rtnl_lock must be held and must not be in atomic section,
 *      in case SWITCHDEV_F_DEFER flag is not set.
 */
int switchdev_port_obj_del(struct net_device *dev,
                           const struct switchdev_obj *obj)
{
        if (obj->flags & SWITCHDEV_F_DEFER)
                return switchdev_port_obj_del_defer(dev, obj);
        ASSERT_RTNL();
        return switchdev_port_obj_del_now(dev, obj);
}
EXPORT_SYMBOL_GPL(switchdev_port_obj_del);

static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain);

/**
 *      register_switchdev_notifier - Register notifier
 *      @nb: notifier_block
 *
 *      Register switch device notifier.
 */
int register_switchdev_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&switchdev_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(register_switchdev_notifier);

/**
 *      unregister_switchdev_notifier - Unregister notifier
 *      @nb: notifier_block
 *
 *      Unregister switch device notifier.
 */
int unregister_switchdev_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&switchdev_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_switchdev_notifier);

/**
 *      call_switchdev_notifiers - Call notifiers
 *      @val: value passed unmodified to notifier function
 *      @dev: port device
 *      @info: notifier information data
 *
 *      Call all network notifier blocks.
 */
int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
                             struct switchdev_notifier_info *info)
{
        info->dev = dev;
        return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
}
EXPORT_SYMBOL_GPL(call_switchdev_notifiers);

bool switchdev_port_same_parent_id(struct net_device *a,
                                   struct net_device *b)
{
        struct switchdev_attr a_attr = {
                .orig_dev = a,
                .id = SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
        };
        struct switchdev_attr b_attr = {
                .orig_dev = b,
                .id = SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
        };

        if (switchdev_port_attr_get(a, &a_attr) ||
            switchdev_port_attr_get(b, &b_attr))
                return false;

        return netdev_phys_item_id_same(&a_attr.u.ppid, &b_attr.u.ppid);
}
EXPORT_SYMBOL_GPL(switchdev_port_same_parent_id);