/*
* 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/types.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/cgroup.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
struct cgroup_cls_state
{
struct cgroup_subsys_state css;
u32 classid;
};
static inline struct cgroup_cls_state *net_cls_state(struct cgroup *cgrp)
{
return (struct cgroup_cls_state *)
cgroup_subsys_state(cgrp, net_cls_subsys_id);
}
static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
struct cgroup *cgrp)
{
struct cgroup_cls_state *cs;
if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL)))
return ERR_PTR(-ENOMEM);
if (cgrp->parent)
cs->classid = net_cls_state(cgrp->parent)->classid;
return &cs->css;
}
static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
{
kfree(ss);
}
static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
{
return net_cls_state(cgrp)->classid;
}
static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
{
if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
net_cls_state(cgrp)->classid = (u32) value;
cgroup_unlock();
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 cgroup_subsys net_cls_subsys = {
.name = "net_cls",
.create = cgrp_create,
.destroy = cgrp_destroy,
.populate = cgrp_populate,
.subsys_id = net_cls_subsys_id,
};
struct cls_cgroup_head
{
u32 handle;
struct tcf_exts exts;
struct tcf_ematch_tree ematches;
};
static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp,
struct tcf_result *res)
{
struct cls_cgroup_head *head = tp->root;
struct cgroup_cls_state *cs;
int ret = 0;
/*
* 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 (softirq_count() != SOFTIRQ_OFFSET)
return -1;
rcu_read_lock();
cs = (struct cgroup_cls_state *) task_subsys_state(current,
net_cls_subsys_id);
if (cs->classid && tcf_em_tree_match(skb, &head->ematches, NULL)) {
res->classid = cs->classid;
res->class = 0;
ret = tcf_exts_exec(skb, &head->exts, res);
} else
ret = -1;
rcu_read_unlock();
return ret;
}
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 (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;
head = (struct cls_cgroup_head *)xchg(&tp->root, NULL);
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)
{
return register_tcf_proto_ops(&cls_cgroup_ops);
}
static void __exit exit_cgroup_cls(void)
{
unregister_tcf_proto_ops(&cls_cgroup_ops);
}
module_init(init_cgroup_cls);
module_exit(exit_cgroup_cls);
MODULE_LICENSE("GPL");
