/*
* net/core/netprio_cgroup.c Priority Control Group
*
* 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.
*
* Authors: Neil Horman <nhorman@tuxdriver.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/cgroup.h>
#include <linux/rcupdate.h>
#include <linux/atomic.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>
#include <net/netprio_cgroup.h>
#define PRIOIDX_SZ 128
static unsigned long prioidx_map[PRIOIDX_SZ];
static DEFINE_SPINLOCK(prioidx_map_lock);
static atomic_t max_prioidx = ATOMIC_INIT(0);
static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
{
return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
struct cgroup_netprio_state, css);
}
static int get_prioidx(u32 *prio)
{
unsigned long flags;
u32 prioidx;
spin_lock_irqsave(&prioidx_map_lock, flags);
prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
spin_unlock_irqrestore(&prioidx_map_lock, flags);
return -ENOSPC;
}
set_bit(prioidx, prioidx_map);
if (atomic_read(&max_prioidx) < prioidx)
atomic_set(&max_prioidx, prioidx);
spin_unlock_irqrestore(&prioidx_map_lock, flags);
*prio = prioidx;
return 0;
}
static void put_prioidx(u32 idx)
{
unsigned long flags;
spin_lock_irqsave(&prioidx_map_lock, flags);
clear_bit(idx, prioidx_map);
spin_unlock_irqrestore(&prioidx_map_lock, flags);
}
static void extend_netdev_table(struct net_device *dev, u32 new_len)
{
size_t new_size = sizeof(struct netprio_map) +
((sizeof(u32) * new_len));
struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
struct netprio_map *old_priomap;
int i;
old_priomap = rtnl_dereference(dev->priomap);
if (!new_priomap) {
pr_warn("Unable to alloc new priomap!\n");
return;
}
for (i = 0;
old_priomap && (i < old_priomap->priomap_len);
i++)
new_priomap->priomap[i] = old_priomap->priomap[i];
new_priomap->priomap_len = new_len;
rcu_assign_pointer(dev->priomap, new_priomap);
if (old_priomap)
kfree_rcu(old_priomap, rcu);
}
static void update_netdev_tables(void)
{
struct net_device *dev;
u32 max_len = atomic_read(&max_prioidx) + 1;
struct netprio_map *map;
rtnl_lock();
for_each_netdev(&init_net, dev) {
map = rtnl_dereference(dev->priomap);
if ((!map) ||
(map->priomap_len < max_len))
extend_netdev_table(dev, max_len);
}
rtnl_unlock();
}
static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
{
struct cgroup_netprio_state *cs;
int ret;
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return ERR_PTR(-ENOMEM);
if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) {
kfree(cs);
return ERR_PTR(-EINVAL);
}
ret = get_prioidx(&cs->prioidx);
if (ret != 0) {
pr_warn("No space in priority index array\n");
kfree(cs);
return ERR_PTR(ret);
}
return &cs->css;
}
static void cgrp_destroy(struct cgroup *cgrp)
{
struct cgroup_netprio_state *cs;
struct net_device *dev;
struct netprio_map *map;
cs = cgrp_netprio_state(cgrp);
rtnl_lock();
for_each_netdev(&init_net, dev) {
map = rtnl_dereference(dev->priomap);
if (map)
map->priomap[cs->prioidx] = 0;
}
rtnl_unlock();
put_prioidx(cs->prioidx);
kfree(cs);
}
static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
{
return (u64)cgrp_netprio_state(cgrp)->prioidx;
}
static int read_priomap(struct cgroup *cont, struct cftype *cft,
struct cgroup_map_cb *cb)
{
struct net_device *dev;
u32 prioidx = cgrp_netprio_state(cont)->prioidx;
u32 priority;
struct netprio_map *map;
rcu_read_lock();
for_each_netdev_rcu(&init_net, dev) {
map = rcu_dereference(dev->priomap);
priority = map ? map->priomap[prioidx] : 0;
cb->fill(cb, dev->name, priority);
}
rcu_read_unlock();
return 0;
}
static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
{
char *devname = kstrdup(buffer, GFP_KERNEL);
int ret = -EINVAL;
u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
unsigned long priority;
char *priostr;
struct net_device *dev;
struct netprio_map *map;
if (!devname)
return -ENOMEM;
/*
* Minimally sized valid priomap string
*/
if (strlen(devname) < 3)
goto out_free_devname;
priostr = strstr(devname, " ");
if (!priostr)
goto out_free_devname;
/*
*Separate the devname from the associated priority
*and advance the priostr poitner to the priority value
*/
*priostr = '\0';
priostr++;
/*
* If the priostr points to NULL, we're at the end of the passed
* in string, and its not a valid write
*/
if (*priostr == '\0')
goto out_free_devname;
ret = kstrtoul(priostr, 10, &priority);
if (ret < 0)
goto out_free_devname;
ret = -ENODEV;
dev = dev_get_by_name(&init_net, devname);
if (!dev)
goto out_free_devname;
update_netdev_tables();
ret = 0;
rcu_read_lock();
map = rcu_dereference(dev->priomap);
if (map)
map->priomap[prioidx] = priority;
rcu_read_unlock();
dev_put(dev);
out_free_devname:
kfree(devname);
return ret;
}
static struct cftype ss_files[] = {
{
.name = "prioidx",
.read_u64 = read_prioidx,
},
{
.name = "ifpriomap",
.read_map = read_priomap,
.write_string = write_priomap,
},
{ } /* terminate */
};
struct cgroup_subsys net_prio_subsys = {
.name = "net_prio",
.create = cgrp_create,
.destroy = cgrp_destroy,
#ifdef CONFIG_NETPRIO_CGROUP
.subsys_id = net_prio_subsys_id,
#endif
.base_cftypes = ss_files,
.module = THIS_MODULE
};
static int netprio_device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
struct netprio_map *old;
/*
* Note this is called with rtnl_lock held so we have update side
* protection on our rcu assignments
*/
switch (event) {
case NETDEV_UNREGISTER:
old = rtnl_dereference(dev->priomap);
RCU_INIT_POINTER(dev->priomap, NULL);
if (old)
kfree_rcu(old, rcu);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block netprio_device_notifier = {
.notifier_call = netprio_device_event
};
static int __init init_cgroup_netprio(void)
{
int ret;
ret = cgroup_load_subsys(&net_prio_subsys);
if (ret)
goto out;
#ifndef CONFIG_NETPRIO_CGROUP
smp_wmb();
net_prio_subsys_id = net_prio_subsys.subsys_id;
#endif
register_netdevice_notifier(&netprio_device_notifier);
out:
return ret;
}
static void __exit exit_cgroup_netprio(void)
{
struct netprio_map *old;
struct net_device *dev;
unregister_netdevice_notifier(&netprio_device_notifier);
cgroup_unload_subsys(&net_prio_subsys);
#ifndef CONFIG_NETPRIO_CGROUP
net_prio_subsys_id = -1;
synchronize_rcu();
#endif
rtnl_lock();
for_each_netdev(&init_net, dev) {
old = rtnl_dereference(dev->priomap);
RCU_INIT_POINTER(dev->priomap, NULL);
if (old)
kfree_rcu(old, rcu);
}
rtnl_unlock();
}
module_init(init_cgroup_netprio);
module_exit(exit_cgroup_netprio);
MODULE_LICENSE("GPL v2");