1 /*
2  * drivers/net/team/team_mode_random.c - Random mode for team
3  * Copyright (c) 2013 Jiri Pirko <jiri@resnulli.us>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/skbuff.h>
16 #include <linux/reciprocal_div.h>
17 #include <linux/if_team.h>
18 
19 static u32 random_N(unsigned int N)
20 {
21 	return reciprocal_divide(prandom_u32(), N);
22 }
23 
24 static bool rnd_transmit(struct team *team, struct sk_buff *skb)
25 {
26 	struct team_port *port;
27 	int port_index;
28 
29 	port_index = random_N(team->en_port_count);
30 	port = team_get_port_by_index_rcu(team, port_index);
31 	if (unlikely(!port))
32 		goto drop;
33 	port = team_get_first_port_txable_rcu(team, port);
34 	if (unlikely(!port))
35 		goto drop;
36 	if (team_dev_queue_xmit(team, port, skb))
37 		return false;
38 	return true;
39 
40 drop:
41 	dev_kfree_skb_any(skb);
42 	return false;
43 }
44 
45 static const struct team_mode_ops rnd_mode_ops = {
46 	.transmit		= rnd_transmit,
47 	.port_enter		= team_modeop_port_enter,
48 	.port_change_dev_addr	= team_modeop_port_change_dev_addr,
49 };
50 
51 static const struct team_mode rnd_mode = {
52 	.kind		= "random",
53 	.owner		= THIS_MODULE,
54 	.ops		= &rnd_mode_ops,
55 };
56 
57 static int __init rnd_init_module(void)
58 {
59 	return team_mode_register(&rnd_mode);
60 }
61 
62 static void __exit rnd_cleanup_module(void)
63 {
64 	team_mode_unregister(&rnd_mode);
65 }
66 
67 module_init(rnd_init_module);
68 module_exit(rnd_cleanup_module);
69 
70 MODULE_LICENSE("GPL v2");
71 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
72 MODULE_DESCRIPTION("Random mode for team");
73 MODULE_ALIAS("team-mode-random");
74