net/core/netprio_cgroup.c - linux - Git at Google

 /*
  * 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);
 	spin_unlock_irqrestore(&prioidx_map_lock, flags);
 	atomic_set(&max_prioidx, prioidx);
 	*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");
	/*
	* 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);
	spin_unlock_irqrestore(&prioidx_map_lock, flags);
	atomic_set(&max_prioidx, prioidx);
	*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");