team_mode_activebackup.c

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/*
 * drivers/net/team/team_mode_activebackup.c - Active-backup mode for team
 * Copyright (c) 2011 Jiri Pirko <[email protected]>
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <net/rtnetlink.h>
#include <linux/if_team.h>

struct ab_priv {
    struct team_port __rcu *active_port;
};

static struct ab_priv *ab_priv(struct team *team)
{
    return (struct ab_priv *) &team->mode_priv;
}

static rx_handler_result_t ab_receive(struct team *team, struct team_port *port,
                      struct sk_buff *skb) {
    struct team_port *active_port;

    active_port = rcu_dereference(ab_priv(team)->active_port);
    if (active_port != port)
        return RX_HANDLER_EXACT;
    return RX_HANDLER_ANOTHER;
}

static bool ab_transmit(struct team *team, struct sk_buff *skb)
{
    struct team_port *active_port;

    active_port = rcu_dereference_bh(ab_priv(team)->active_port);
    if (unlikely(!active_port))
        goto drop;
    if (team_dev_queue_xmit(team, active_port, skb))
        return false;
    return true;

drop:
    dev_kfree_skb_any(skb);
    return false;
}

static void ab_port_leave(struct team *team, struct team_port *port)
{
    if (ab_priv(team)->active_port == port)
        RCU_INIT_POINTER(ab_priv(team)->active_port, NULL);
}

static int ab_active_port_get(struct team *team, struct team_gsetter_ctx *ctx)
{
    struct team_port *active_port;

    active_port = rcu_dereference_protected(ab_priv(team)->active_port,
                        lockdep_is_held(&team->lock));
    if (active_port)
        ctx->data.u32_val = active_port->dev->ifindex;
    else
        ctx->data.u32_val = 0;
    return 0;
}

static int ab_active_port_set(struct team *team, struct team_gsetter_ctx *ctx)
{
    struct team_port *port;

    list_for_each_entry(port, &team->port_list, list) {
        if (port->dev->ifindex == ctx->data.u32_val) {
            rcu_assign_pointer(ab_priv(team)->active_port, port);
            return 0;
        }
    }
    return -ENOENT;
}

static const struct team_option ab_options[] = {
    {
        .name = "activeport",
        .type = TEAM_OPTION_TYPE_U32,
        .getter = ab_active_port_get,
        .setter = ab_active_port_set,
    },
};

static int ab_init(struct team *team)
{
    return team_options_register(team, ab_options, ARRAY_SIZE(ab_options));
}

static void ab_exit(struct team *team)
{
    team_options_unregister(team, ab_options, ARRAY_SIZE(ab_options));
}

static const struct team_mode_ops ab_mode_ops = {
    .init           = ab_init,
    .exit           = ab_exit,
    .receive        = ab_receive,
    .transmit       = ab_transmit,
    .port_leave     = ab_port_leave,
};

static const struct team_mode ab_mode = {
    .kind       = "activebackup",
    .owner      = THIS_MODULE,
    .priv_size  = sizeof(struct ab_priv),
    .ops        = &ab_mode_ops,
};

static int __init ab_init_module(void)
{
    return team_mode_register(&ab_mode);
}

static void __exit ab_cleanup_module(void)
{
    team_mode_unregister(&ab_mode);
}

module_init(ab_init_module);
module_exit(ab_cleanup_module);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Jiri Pirko <[email protected]>");
MODULE_DESCRIPTION("Active-backup mode for team");
MODULE_ALIAS("team-mode-activebackup");