kernel-ark/drivers/net/team/team_mode_random.c
Jiri Pirko 76c455decb team: check return value of team_get_port_by_index_rcu() for NULL
team_get_port_by_index_rcu() might return NULL due to race between port
removal and skb tx path. Panic is easily triggeable when txing packets
and adding/removing port in a loop.

introduced by commit 3d249d4ca "net: introduce ethernet teaming device"
and commit 753f993911 "team: introduce random mode" (for random mode)

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-12 00:56:27 -07:00

74 lines
1.7 KiB
C

/*
* drivers/net/team/team_mode_random.c - Random mode for team
* Copyright (c) 2013 Jiri Pirko <jiri@resnulli.us>
*
* 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/skbuff.h>
#include <linux/reciprocal_div.h>
#include <linux/if_team.h>
static u32 random_N(unsigned int N)
{
return reciprocal_divide(prandom_u32(), N);
}
static bool rnd_transmit(struct team *team, struct sk_buff *skb)
{
struct team_port *port;
int port_index;
port_index = random_N(team->en_port_count);
port = team_get_port_by_index_rcu(team, port_index);
if (unlikely(!port))
goto drop;
port = team_get_first_port_txable_rcu(team, port);
if (unlikely(!port))
goto drop;
if (team_dev_queue_xmit(team, port, skb))
return false;
return true;
drop:
dev_kfree_skb_any(skb);
return false;
}
static const struct team_mode_ops rnd_mode_ops = {
.transmit = rnd_transmit,
.port_enter = team_modeop_port_enter,
.port_change_dev_addr = team_modeop_port_change_dev_addr,
};
static const struct team_mode rnd_mode = {
.kind = "random",
.owner = THIS_MODULE,
.ops = &rnd_mode_ops,
};
static int __init rnd_init_module(void)
{
return team_mode_register(&rnd_mode);
}
static void __exit rnd_cleanup_module(void)
{
team_mode_unregister(&rnd_mode);
}
module_init(rnd_init_module);
module_exit(rnd_cleanup_module);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
MODULE_DESCRIPTION("Random mode for team");
MODULE_ALIAS("team-mode-random");