[mirror_ubuntu-bionic-kernel.git] / net / core / netprio_cgroup.c

/*
 * 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>

#include <linux/fdtable.h>

#define PRIOMAP_MIN_SZ		128

/*
 * Extend @dev->priomap so that it's large enough to accommodate
 * @target_idx.  @dev->priomap.priomap_len > @target_idx after successful
 * return.  Must be called under rtnl lock.
 */
static int extend_netdev_table(struct net_device *dev, u32 target_idx)
{
	struct netprio_map *old, *new;
	size_t new_sz, new_len;

	/* is the existing priomap large enough? */
	old = rtnl_dereference(dev->priomap);
	if (old && old->priomap_len > target_idx)
		return 0;

	/*
	 * Determine the new size.  Let's keep it power-of-two.  We start
	 * from PRIOMAP_MIN_SZ and double it until it's large enough to
	 * accommodate @target_idx.
	 */
	new_sz = PRIOMAP_MIN_SZ;
	while (true) {
		new_len = (new_sz - offsetof(struct netprio_map, priomap)) /
			sizeof(new->priomap[0]);
		if (new_len > target_idx)
			break;
		new_sz *= 2;
		/* overflowed? */
		if (WARN_ON(new_sz < PRIOMAP_MIN_SZ))
			return -ENOSPC;
	}

	/* allocate & copy */
	new = kzalloc(new_sz, GFP_KERNEL);
	if (!new)
		return -ENOMEM;

	if (old)
		memcpy(new->priomap, old->priomap,
		       old->priomap_len * sizeof(old->priomap[0]));

	new->priomap_len = new_len;

	/* install the new priomap */
	rcu_assign_pointer(dev->priomap, new);
	if (old)
		kfree_rcu(old, rcu);
	return 0;
}

/**
 * netprio_prio - return the effective netprio of a cgroup-net_device pair
 * @css: css part of the target pair
 * @dev: net_device part of the target pair
 *
 * Should be called under RCU read or rtnl lock.
 */
static u32 netprio_prio(struct cgroup_subsys_state *css, struct net_device *dev)
{
	struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
	int id = css->cgroup->id;

	if (map && id < map->priomap_len)
		return map->priomap[id];
	return 0;
}

/**
 * netprio_set_prio - set netprio on a cgroup-net_device pair
 * @css: css part of the target pair
 * @dev: net_device part of the target pair
 * @prio: prio to set
 *
 * Set netprio to @prio on @css-@dev pair.  Should be called under rtnl
 * lock and may fail under memory pressure for non-zero @prio.
 */
static int netprio_set_prio(struct cgroup_subsys_state *css,
			    struct net_device *dev, u32 prio)
{
	struct netprio_map *map;
	int id = css->cgroup->id;
	int ret;

	/* avoid extending priomap for zero writes */
	map = rtnl_dereference(dev->priomap);
	if (!prio && (!map || map->priomap_len <= id))
		return 0;

	ret = extend_netdev_table(dev, id);
	if (ret)
		return ret;

	map = rtnl_dereference(dev->priomap);
	map->priomap[id] = prio;
	return 0;
}

static struct cgroup_subsys_state *
cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
{
	struct cgroup_subsys_state *css;

	css = kzalloc(sizeof(*css), GFP_KERNEL);
	if (!css)
		return ERR_PTR(-ENOMEM);

	return css;
}

static int cgrp_css_online(struct cgroup_subsys_state *css)
{
	struct cgroup_subsys_state *parent_css = css->parent;
	struct net_device *dev;
	int ret = 0;

	if (!parent_css)
		return 0;

	rtnl_lock();
	/*
	 * Inherit prios from the parent.  As all prios are set during
	 * onlining, there is no need to clear them on offline.
	 */
	for_each_netdev(&init_net, dev) {
		u32 prio = netprio_prio(parent_css, dev);

		ret = netprio_set_prio(css, dev, prio);
		if (ret)
			break;
	}
	rtnl_unlock();
	return ret;
}

static void cgrp_css_free(struct cgroup_subsys_state *css)
{
	kfree(css);
}

static u64 read_prioidx(struct cgroup_subsys_state *css, struct cftype *cft)
{
	return css->cgroup->id;
}

static int read_priomap(struct seq_file *sf, void *v)
{
	struct net_device *dev;

	rcu_read_lock();
	for_each_netdev_rcu(&init_net, dev)
		seq_printf(sf, "%s %u\n", dev->name,
			   netprio_prio(seq_css(sf), dev));
	rcu_read_unlock();
	return 0;
}

static ssize_t write_priomap(struct kernfs_open_file *of,
			     char *buf, size_t nbytes, loff_t off)
{
	char devname[IFNAMSIZ + 1];
	struct net_device *dev;
	u32 prio;
	int ret;

	if (sscanf(buf, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
		return -EINVAL;

	dev = dev_get_by_name(&init_net, devname);
	if (!dev)
		return -ENODEV;

	rtnl_lock();

	ret = netprio_set_prio(of_css(of), dev, prio);

	rtnl_unlock();
	dev_put(dev);
	return ret ?: nbytes;
}

static int update_netprio(const void *v, struct file *file, unsigned n)
{
	int err;
	struct socket *sock = sock_from_file(file, &err);
	if (sock)
		sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
	return 0;
}

static void net_prio_attach(struct cgroup_subsys_state *css,
			    struct cgroup_taskset *tset)
{
	struct task_struct *p;
	void *v = (void *)(unsigned long)css->cgroup->id;

	cgroup_taskset_for_each(p, tset) {
		task_lock(p);
		iterate_fd(p->files, 0, update_netprio, v);
		task_unlock(p);
	}
}

static struct cftype ss_files[] = {
	{
		.name = "prioidx",
		.read_u64 = read_prioidx,
	},
	{
		.name = "ifpriomap",
		.seq_show = read_priomap,
		.write = write_priomap,
	},
	{ }	/* terminate */
};

struct cgroup_subsys net_prio_cgrp_subsys = {
	.css_alloc	= cgrp_css_alloc,
	.css_online	= cgrp_css_online,
	.css_free	= cgrp_css_free,
	.attach		= net_prio_attach,
	.legacy_cftypes	= ss_files,
};

static int netprio_device_event(struct notifier_block *unused,
				unsigned long event, void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_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)
{
	register_netdevice_notifier(&netprio_device_notifier);
	return 0;
}

subsys_initcall(init_cgroup_netprio);
MODULE_LICENSE("GPL v2");
Commit	Line	Data
	1	/*
	2	* net/core/netprio_cgroup.c Priority Control Group
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*
	9	* Authors: Neil Horman <nhorman@tuxdriver.com>
	10	*/
	11
	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	13
	14	#include <linux/module.h>
	15	#include <linux/slab.h>
	16	#include <linux/types.h>
	17	#include <linux/string.h>
	18	#include <linux/errno.h>
	19	#include <linux/skbuff.h>
	20	#include <linux/cgroup.h>
	21	#include <linux/rcupdate.h>
	22	#include <linux/atomic.h>
	23	#include <net/rtnetlink.h>
	24	#include <net/pkt_cls.h>
	25	#include <net/sock.h>
	26	#include <net/netprio_cgroup.h>
	27
	28	#include <linux/fdtable.h>
	29
	30	#define PRIOMAP_MIN_SZ 128
	31
	32	/*
	33	* Extend @dev->priomap so that it's large enough to accommodate
	34	* @target_idx. @dev->priomap.priomap_len > @target_idx after successful
	35	* return. Must be called under rtnl lock.
	36	*/
	37	static int extend_netdev_table(struct net_device *dev, u32 target_idx)
	38	{
	39	struct netprio_map old, new;
	40	size_t new_sz, new_len;
	41
	42	/* is the existing priomap large enough? */
	43	old = rtnl_dereference(dev->priomap);
	44	if (old && old->priomap_len > target_idx)
	45	return 0;
	46
	47	/*
	48	* Determine the new size. Let's keep it power-of-two. We start
	49	* from PRIOMAP_MIN_SZ and double it until it's large enough to
	50	* accommodate @target_idx.
	51	*/
	52	new_sz = PRIOMAP_MIN_SZ;
	53	while (true) {
	54	new_len = (new_sz - offsetof(struct netprio_map, priomap)) /
	55	sizeof(new->priomap[0]);
	56	if (new_len > target_idx)
	57	break;
	58	new_sz *= 2;
	59	/* overflowed? */
	60	if (WARN_ON(new_sz < PRIOMAP_MIN_SZ))
	61	return -ENOSPC;
	62	}
	63
	64	/* allocate & copy */
	65	new = kzalloc(new_sz, GFP_KERNEL);
	66	if (!new)
	67	return -ENOMEM;
	68
	69	if (old)
	70	memcpy(new->priomap, old->priomap,
	71	old->priomap_len * sizeof(old->priomap[0]));
	72
	73	new->priomap_len = new_len;
	74
	75	/* install the new priomap */
	76	rcu_assign_pointer(dev->priomap, new);
	77	if (old)
	78	kfree_rcu(old, rcu);
	79	return 0;
	80	}
	81
	82	/**
	83	* netprio_prio - return the effective netprio of a cgroup-net_device pair
	84	* @css: css part of the target pair
	85	* @dev: net_device part of the target pair
	86	*
	87	* Should be called under RCU read or rtnl lock.
	88	*/
	89	static u32 netprio_prio(struct cgroup_subsys_state css, struct net_device dev)
	90	{
	91	struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
	92	int id = css->cgroup->id;
	93
	94	if (map && id < map->priomap_len)
	95	return map->priomap[id];
	96	return 0;
	97	}
	98
	99	/**
	100	* netprio_set_prio - set netprio on a cgroup-net_device pair
	101	* @css: css part of the target pair
	102	* @dev: net_device part of the target pair
	103	* @prio: prio to set
	104	*
	105	* Set netprio to @prio on @css-@dev pair. Should be called under rtnl
	106	* lock and may fail under memory pressure for non-zero @prio.
	107	*/
	108	static int netprio_set_prio(struct cgroup_subsys_state *css,
	109	struct net_device *dev, u32 prio)
	110	{
	111	struct netprio_map *map;
	112	int id = css->cgroup->id;
	113	int ret;
	114
	115	/* avoid extending priomap for zero writes */
	116	map = rtnl_dereference(dev->priomap);
	117	if (!prio && (!map \|\| map->priomap_len <= id))
	118	return 0;
	119
	120	ret = extend_netdev_table(dev, id);
	121	if (ret)
	122	return ret;
	123
	124	map = rtnl_dereference(dev->priomap);
	125	map->priomap[id] = prio;
	126	return 0;
	127	}
	128
	129	static struct cgroup_subsys_state *
	130	cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
	131	{
	132	struct cgroup_subsys_state *css;
	133
	134	css = kzalloc(sizeof(*css), GFP_KERNEL);
	135	if (!css)
	136	return ERR_PTR(-ENOMEM);
	137
	138	return css;
	139	}
	140
	141	static int cgrp_css_online(struct cgroup_subsys_state *css)
	142	{
	143	struct cgroup_subsys_state *parent_css = css->parent;
	144	struct net_device *dev;
	145	int ret = 0;
	146
	147	if (!parent_css)
	148	return 0;
	149
	150	rtnl_lock();
	151	/*
	152	* Inherit prios from the parent. As all prios are set during
	153	* onlining, there is no need to clear them on offline.
	154	*/
	155	for_each_netdev(&init_net, dev) {
	156	u32 prio = netprio_prio(parent_css, dev);
	157
	158	ret = netprio_set_prio(css, dev, prio);
	159	if (ret)
	160	break;
	161	}
	162	rtnl_unlock();
	163	return ret;
	164	}
	165
	166	static void cgrp_css_free(struct cgroup_subsys_state *css)
	167	{
	168	kfree(css);
	169	}
	170
	171	static u64 read_prioidx(struct cgroup_subsys_state css, struct cftype cft)
	172	{
	173	return css->cgroup->id;
	174	}
	175
	176	static int read_priomap(struct seq_file sf, void v)
	177	{
	178	struct net_device *dev;
	179
	180	rcu_read_lock();
	181	for_each_netdev_rcu(&init_net, dev)
	182	seq_printf(sf, "%s %u\n", dev->name,
	183	netprio_prio(seq_css(sf), dev));
	184	rcu_read_unlock();
	185	return 0;
	186	}
	187
	188	static ssize_t write_priomap(struct kernfs_open_file *of,
	189	char *buf, size_t nbytes, loff_t off)
	190	{
	191	char devname[IFNAMSIZ + 1];
	192	struct net_device *dev;
	193	u32 prio;
	194	int ret;
	195
	196	if (sscanf(buf, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
	197	return -EINVAL;
	198
	199	dev = dev_get_by_name(&init_net, devname);
	200	if (!dev)
	201	return -ENODEV;
	202
	203	rtnl_lock();
	204
	205	ret = netprio_set_prio(of_css(of), dev, prio);
	206
	207	rtnl_unlock();
	208	dev_put(dev);
	209	return ret ?: nbytes;
	210	}
	211
	212	static int update_netprio(const void v, struct file file, unsigned n)
	213	{
	214	int err;
	215	struct socket *sock = sock_from_file(file, &err);
	216	if (sock)
	217	sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
	218	return 0;
	219	}
	220
	221	static void net_prio_attach(struct cgroup_subsys_state *css,
	222	struct cgroup_taskset *tset)
	223	{
	224	struct task_struct *p;
	225	void v = (void )(unsigned long)css->cgroup->id;
	226
	227	cgroup_taskset_for_each(p, tset) {
	228	task_lock(p);
	229	iterate_fd(p->files, 0, update_netprio, v);
	230	task_unlock(p);
	231	}
	232	}
	233
	234	static struct cftype ss_files[] = {
	235	{
	236	.name = "prioidx",
	237	.read_u64 = read_prioidx,
	238	},
	239	{
	240	.name = "ifpriomap",
	241	.seq_show = read_priomap,
	242	.write = write_priomap,
	243	},
	244	{ } /* terminate */
	245	};
	246
	247	struct cgroup_subsys net_prio_cgrp_subsys = {
	248	.css_alloc = cgrp_css_alloc,
	249	.css_online = cgrp_css_online,
	250	.css_free = cgrp_css_free,
	251	.attach = net_prio_attach,
	252	.legacy_cftypes = ss_files,
	253	};
	254
	255	static int netprio_device_event(struct notifier_block *unused,
	256	unsigned long event, void *ptr)
	257	{
	258	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	259	struct netprio_map *old;
	260
	261	/*
	262	* Note this is called with rtnl_lock held so we have update side
	263	* protection on our rcu assignments
	264	*/
	265
	266	switch (event) {
	267	case NETDEV_UNREGISTER:
	268	old = rtnl_dereference(dev->priomap);
	269	RCU_INIT_POINTER(dev->priomap, NULL);
	270	if (old)
	271	kfree_rcu(old, rcu);
	272	break;
	273	}
	274	return NOTIFY_DONE;
	275	}
	276
	277	static struct notifier_block netprio_device_notifier = {
	278	.notifier_call = netprio_device_event
	279	};
	280
	281	static int __init init_cgroup_netprio(void)
	282	{
	283	register_netdevice_notifier(&netprio_device_notifier);
	284	return 0;
	285	}
	286
	287	subsys_initcall(init_cgroup_netprio);
	288	MODULE_LICENSE("GPL v2");