net/sched/cls_cgroup.c - kernel/windcharger - Git at Google

 /*
  * net/sched/cls_cgroup.c	Control Group Classifier
  *
  *		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:	Thomas Graf <tgraf@suug.ch>
  */

 #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 <net/rtnetlink.h>
 #include <net/pkt_cls.h>
 #include <net/sock.h>
 #include <net/cls_cgroup.h>

 static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
 					       struct cgroup *cgrp);
 static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
 static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);

 struct cgroup_subsys net_cls_subsys = {
 	.name		= "net_cls",
 	.create		= cgrp_create,
 	.destroy	= cgrp_destroy,
 	.populate	= cgrp_populate,
 #ifdef CONFIG_NET_CLS_CGROUP
 	.subsys_id	= net_cls_subsys_id,
 #endif
 	.module		= THIS_MODULE,
 };


 static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
 {
 	return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
 			    struct cgroup_cls_state, css);
 }

 static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
 {
 	return container_of(task_subsys_state(p, net_cls_subsys_id),
 			    struct cgroup_cls_state, css);
 }

 static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
 						 struct cgroup *cgrp)
 {
 	struct cgroup_cls_state *cs;

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

 	if (cgrp->parent)
 		cs->classid = cgrp_cls_state(cgrp->parent)->classid;

 	return &cs->css;
 }

 static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
 {
 	kfree(cgrp_cls_state(cgrp));
 }

 static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
 {
 	return cgrp_cls_state(cgrp)->classid;
 }

 static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
 {
 	cgrp_cls_state(cgrp)->classid = (u32) value;
 	return 0;
 }

 static struct cftype ss_files[] = {
 	{
 		.name = "classid",
 		.read_u64 = read_classid,
 		.write_u64 = write_classid,
 	},
 };

 static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
 {
 	return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
 }

 struct cls_cgroup_head {
 	u32			handle;
 	struct tcf_exts		exts;
 	struct tcf_ematch_tree	ematches;
 };

 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 			       struct tcf_result *res)
 {
 	struct cls_cgroup_head *head = tp->root;
 	u32 classid;

 	rcu_read_lock();
 	classid = task_cls_state(current)->classid;
 	rcu_read_unlock();

 	/*
 	 * Due to the nature of the classifier it is required to ignore all
 	 * packets originating from softirq context as accessing `current'
 	 * would lead to false results.
 	 *
 	 * This test assumes that all callers of dev_queue_xmit() explicitely
 	 * disable bh. Knowing this, it is possible to detect softirq based
 	 * calls by looking at the number of nested bh disable calls because
 	 * softirqs always disables bh.
 	 */
 	if (in_serving_softirq()) {
 		/* If there is an sk_classid we'll use that. */
 		if (!skb->sk)
 			return -1;
 		classid = skb->sk->sk_classid;
 	}

 	if (!classid)
 		return -1;

 	if (!tcf_em_tree_match(skb, &head->ematches, NULL))
 		return -1;

 	res->classid = classid;
 	res->class = 0;
 	return tcf_exts_exec(skb, &head->exts, res);
 }

 static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
 {
 	return 0UL;
 }

 static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
 {
 }

 static int cls_cgroup_init(struct tcf_proto *tp)
 {
 	return 0;
 }

 static const struct tcf_ext_map cgroup_ext_map = {
 	.action = TCA_CGROUP_ACT,
 	.police = TCA_CGROUP_POLICE,
 };

 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
 	[TCA_CGROUP_EMATCHES]	= { .type = NLA_NESTED },
 };

 static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base,
 			     u32 handle, struct nlattr **tca,
 			     unsigned long *arg)
 {
 	struct nlattr *tb[TCA_CGROUP_MAX + 1];
 	struct cls_cgroup_head *head = tp->root;
 	struct tcf_ematch_tree t;
 	struct tcf_exts e;
 	int err;

 	if (!tca[TCA_OPTIONS])
 		return -EINVAL;

 	if (head == NULL) {
 		if (!handle)
 			return -EINVAL;

 		head = kzalloc(sizeof(*head), GFP_KERNEL);
 		if (head == NULL)
 			return -ENOBUFS;

 		head->handle = handle;

 		tcf_tree_lock(tp);
 		tp->root = head;
 		tcf_tree_unlock(tp);
 	}

 	if (handle != head->handle)
 		return -ENOENT;

 	err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 			       cgroup_policy);
 	if (err < 0)
 		return err;

 	err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map);
 	if (err < 0)
 		return err;

 	err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
 	if (err < 0)
 		return err;

 	tcf_exts_change(tp, &head->exts, &e);
 	tcf_em_tree_change(tp, &head->ematches, &t);

 	return 0;
 }

 static void cls_cgroup_destroy(struct tcf_proto *tp)
 {
 	struct cls_cgroup_head *head = tp->root;

 	if (head) {
 		tcf_exts_destroy(tp, &head->exts);
 		tcf_em_tree_destroy(tp, &head->ematches);
 		kfree(head);
 	}
 }

 static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
 {
 	return -EOPNOTSUPP;
 }

 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 {
 	struct cls_cgroup_head *head = tp->root;

 	if (arg->count < arg->skip)
 		goto skip;

 	if (arg->fn(tp, (unsigned long) head, arg) < 0) {
 		arg->stop = 1;
 		return;
 	}
 skip:
 	arg->count++;
 }

 static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh,
 			   struct sk_buff *skb, struct tcmsg *t)
 {
 	struct cls_cgroup_head *head = tp->root;
 	unsigned char *b = skb_tail_pointer(skb);
 	struct nlattr *nest;

 	t->tcm_handle = head->handle;

 	nest = nla_nest_start(skb, TCA_OPTIONS);
 	if (nest == NULL)
 		goto nla_put_failure;

 	if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 ||
 	    tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 		goto nla_put_failure;

 	nla_nest_end(skb, nest);

 	if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0)
 		goto nla_put_failure;

 	return skb->len;

 nla_put_failure:
 	nlmsg_trim(skb, b);
 	return -1;
 }

 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 	.kind		=	"cgroup",
 	.init		=	cls_cgroup_init,
 	.change		=	cls_cgroup_change,
 	.classify	=	cls_cgroup_classify,
 	.destroy	=	cls_cgroup_destroy,
 	.get		=	cls_cgroup_get,
 	.put		=	cls_cgroup_put,
 	.delete		=	cls_cgroup_delete,
 	.walk		=	cls_cgroup_walk,
 	.dump		=	cls_cgroup_dump,
 	.owner		=	THIS_MODULE,
 };

 static int __init init_cgroup_cls(void)
 {
 	int ret;

 	ret = cgroup_load_subsys(&net_cls_subsys);
 	if (ret)
 		goto out;

 #ifndef CONFIG_NET_CLS_CGROUP
 	/* We can't use rcu_assign_pointer because this is an int. */
 	smp_wmb();
 	net_cls_subsys_id = net_cls_subsys.subsys_id;
 #endif

 	ret = register_tcf_proto_ops(&cls_cgroup_ops);
 	if (ret)
 		cgroup_unload_subsys(&net_cls_subsys);

 out:
 	return ret;
 }

 static void __exit exit_cgroup_cls(void)
 {
 	unregister_tcf_proto_ops(&cls_cgroup_ops);

 #ifndef CONFIG_NET_CLS_CGROUP
 	net_cls_subsys_id = -1;
 	synchronize_rcu();
 #endif

 	cgroup_unload_subsys(&net_cls_subsys);
 }

 module_init(init_cgroup_cls);
 module_exit(exit_cgroup_cls);
 MODULE_LICENSE("GPL");
	/*
	* net/sched/cls_cgroup.c Control Group Classifier
	*
	* 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: Thomas Graf <tgraf@suug.ch>
	*/

	#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 <net/rtnetlink.h>
	#include <net/pkt_cls.h>
	#include <net/sock.h>
	#include <net/cls_cgroup.h>

	static struct cgroup_subsys_state cgrp_create(struct cgroup_subsys ss,
	struct cgroup *cgrp);
	static void cgrp_destroy(struct cgroup_subsys ss, struct cgroup cgrp);
	static int cgrp_populate(struct cgroup_subsys ss, struct cgroup cgrp);

	struct cgroup_subsys net_cls_subsys = {
	.name = "net_cls",
	.create = cgrp_create,
	.destroy = cgrp_destroy,
	.populate = cgrp_populate,
	#ifdef CONFIG_NET_CLS_CGROUP
	.subsys_id = net_cls_subsys_id,
	#endif
	.module = THIS_MODULE,
	};


	static inline struct cgroup_cls_state cgrp_cls_state(struct cgroup cgrp)
	{
	return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
	struct cgroup_cls_state, css);
	}

	static inline struct cgroup_cls_state task_cls_state(struct task_struct p)
	{
	return container_of(task_subsys_state(p, net_cls_subsys_id),
	struct cgroup_cls_state, css);
	}

	static struct cgroup_subsys_state cgrp_create(struct cgroup_subsys ss,
	struct cgroup *cgrp)
	{
	struct cgroup_cls_state *cs;

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

	if (cgrp->parent)
	cs->classid = cgrp_cls_state(cgrp->parent)->classid;

	return &cs->css;
	}

	static void cgrp_destroy(struct cgroup_subsys ss, struct cgroup cgrp)
	{
	kfree(cgrp_cls_state(cgrp));
	}

	static u64 read_classid(struct cgroup cgrp, struct cftype cft)
	{
	return cgrp_cls_state(cgrp)->classid;
	}

	static int write_classid(struct cgroup cgrp, struct cftype cft, u64 value)
	{
	cgrp_cls_state(cgrp)->classid = (u32) value;
	return 0;
	}

	static struct cftype ss_files[] = {
	{
	.name = "classid",
	.read_u64 = read_classid,
	.write_u64 = write_classid,
	},
	};

	static int cgrp_populate(struct cgroup_subsys ss, struct cgroup cgrp)
	{
	return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
	}

	struct cls_cgroup_head {
	u32 handle;
	struct tcf_exts exts;
	struct tcf_ematch_tree ematches;
	};

	static int cls_cgroup_classify(struct sk_buff skb, const struct tcf_proto tp,
	struct tcf_result *res)
	{
	struct cls_cgroup_head *head = tp->root;
	u32 classid;

	rcu_read_lock();
	classid = task_cls_state(current)->classid;
	rcu_read_unlock();

	/*
	* Due to the nature of the classifier it is required to ignore all
	* packets originating from softirq context as accessing `current'
	* would lead to false results.
	*
	* This test assumes that all callers of dev_queue_xmit() explicitely
	* disable bh. Knowing this, it is possible to detect softirq based
	* calls by looking at the number of nested bh disable calls because
	* softirqs always disables bh.
	*/
	if (in_serving_softirq()) {
	/* If there is an sk_classid we'll use that. */
	if (!skb->sk)
	return -1;
	classid = skb->sk->sk_classid;
	}

	if (!classid)
	return -1;

	if (!tcf_em_tree_match(skb, &head->ematches, NULL))
	return -1;

	res->classid = classid;
	res->class = 0;
	return tcf_exts_exec(skb, &head->exts, res);
	}

	static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
	{
	return 0UL;
	}

	static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
	{
	}

	static int cls_cgroup_init(struct tcf_proto *tp)
	{
	return 0;
	}

	static const struct tcf_ext_map cgroup_ext_map = {
	.action = TCA_CGROUP_ACT,
	.police = TCA_CGROUP_POLICE,
	};

	static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
	[TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
	};

	static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base,
	u32 handle, struct nlattr **tca,
	unsigned long *arg)
	{
	struct nlattr *tb[TCA_CGROUP_MAX + 1];
	struct cls_cgroup_head *head = tp->root;
	struct tcf_ematch_tree t;
	struct tcf_exts e;
	int err;

	if (!tca[TCA_OPTIONS])
	return -EINVAL;

	if (head == NULL) {
	if (!handle)
	return -EINVAL;

	head = kzalloc(sizeof(*head), GFP_KERNEL);
	if (head == NULL)
	return -ENOBUFS;

	head->handle = handle;

	tcf_tree_lock(tp);
	tp->root = head;
	tcf_tree_unlock(tp);
	}

	if (handle != head->handle)
	return -ENOENT;

	err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
	cgroup_policy);
	if (err < 0)
	return err;

	err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map);
	if (err < 0)
	return err;

	err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
	if (err < 0)
	return err;

	tcf_exts_change(tp, &head->exts, &e);
	tcf_em_tree_change(tp, &head->ematches, &t);

	return 0;
	}

	static void cls_cgroup_destroy(struct tcf_proto *tp)
	{
	struct cls_cgroup_head *head = tp->root;

	if (head) {
	tcf_exts_destroy(tp, &head->exts);
	tcf_em_tree_destroy(tp, &head->ematches);
	kfree(head);
	}
	}

	static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
	{
	return -EOPNOTSUPP;
	}

	static void cls_cgroup_walk(struct tcf_proto tp, struct tcf_walker arg)
	{
	struct cls_cgroup_head *head = tp->root;

	if (arg->count < arg->skip)
	goto skip;

	if (arg->fn(tp, (unsigned long) head, arg) < 0) {
	arg->stop = 1;
	return;
	}
	skip:
	arg->count++;
	}

	static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh,
	struct sk_buff skb, struct tcmsg t)
	{
	struct cls_cgroup_head *head = tp->root;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;

	t->tcm_handle = head->handle;

	nest = nla_nest_start(skb, TCA_OPTIONS);
	if (nest == NULL)
	goto nla_put_failure;

	if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 \|\|
	tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
	goto nla_put_failure;

	nla_nest_end(skb, nest);

	if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0)
	goto nla_put_failure;

	return skb->len;

	nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
	}

	static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
	.kind = "cgroup",
	.init = cls_cgroup_init,
	.change = cls_cgroup_change,
	.classify = cls_cgroup_classify,
	.destroy = cls_cgroup_destroy,
	.get = cls_cgroup_get,
	.put = cls_cgroup_put,
	.delete = cls_cgroup_delete,
	.walk = cls_cgroup_walk,
	.dump = cls_cgroup_dump,
	.owner = THIS_MODULE,
	};

	static int __init init_cgroup_cls(void)
	{
	int ret;

	ret = cgroup_load_subsys(&net_cls_subsys);
	if (ret)
	goto out;

	#ifndef CONFIG_NET_CLS_CGROUP
	/* We can't use rcu_assign_pointer because this is an int. */
	smp_wmb();
	net_cls_subsys_id = net_cls_subsys.subsys_id;
	#endif

	ret = register_tcf_proto_ops(&cls_cgroup_ops);
	if (ret)
	cgroup_unload_subsys(&net_cls_subsys);

	out:
	return ret;
	}

	static void __exit exit_cgroup_cls(void)
	{
	unregister_tcf_proto_ops(&cls_cgroup_ops);

	#ifndef CONFIG_NET_CLS_CGROUP
	net_cls_subsys_id = -1;
	synchronize_rcu();
	#endif

	cgroup_unload_subsys(&net_cls_subsys);
	}

	module_init(init_cgroup_cls);
	module_exit(exit_cgroup_cls);
	MODULE_LICENSE("GPL");