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linux/net/sched/cls_cgroup.c
Pedro Tammela 9f3101dca3 net/sched: avoid indirect classify functions on retpoline kernels
Expose the necessary tc classifier functions and wire up cls_api to use
direct calls in retpoline kernels.

Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-12-09 09:18:07 +00:00

226 lines
5.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/cls_cgroup.c Control Group Classifier
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/rcupdate.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>
#include <net/cls_cgroup.h>
#include <net/tc_wrapper.h>
struct cls_cgroup_head {
u32 handle;
struct tcf_exts exts;
struct tcf_ematch_tree ematches;
struct tcf_proto *tp;
struct rcu_work rwork;
};
TC_INDIRECT_SCOPE int cls_cgroup_classify(struct sk_buff *skb,
const struct tcf_proto *tp,
struct tcf_result *res)
{
struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
u32 classid = task_get_classid(skb);
if (unlikely(!head))
return -1;
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 void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
{
return NULL;
}
static int cls_cgroup_init(struct tcf_proto *tp)
{
return 0;
}
static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
[TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
};
static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
{
tcf_exts_destroy(&head->exts);
tcf_em_tree_destroy(&head->ematches);
tcf_exts_put_net(&head->exts);
kfree(head);
}
static void cls_cgroup_destroy_work(struct work_struct *work)
{
struct cls_cgroup_head *head = container_of(to_rcu_work(work),
struct cls_cgroup_head,
rwork);
rtnl_lock();
__cls_cgroup_destroy(head);
rtnl_unlock();
}
static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base,
u32 handle, struct nlattr **tca,
void **arg, u32 flags,
struct netlink_ext_ack *extack)
{
struct nlattr *tb[TCA_CGROUP_MAX + 1];
struct cls_cgroup_head *head = rtnl_dereference(tp->root);
struct cls_cgroup_head *new;
int err;
if (!tca[TCA_OPTIONS])
return -EINVAL;
if (!head && !handle)
return -EINVAL;
if (head && handle != head->handle)
return -ENOENT;
new = kzalloc(sizeof(*head), GFP_KERNEL);
if (!new)
return -ENOBUFS;
err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
if (err < 0)
goto errout;
new->handle = handle;
new->tp = tp;
err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX,
tca[TCA_OPTIONS], cgroup_policy,
NULL);
if (err < 0)
goto errout;
err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, flags,
extack);
if (err < 0)
goto errout;
err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
if (err < 0)
goto errout;
rcu_assign_pointer(tp->root, new);
if (head) {
tcf_exts_get_net(&head->exts);
tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
}
return 0;
errout:
tcf_exts_destroy(&new->exts);
kfree(new);
return err;
}
static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held,
struct netlink_ext_ack *extack)
{
struct cls_cgroup_head *head = rtnl_dereference(tp->root);
/* Head can still be NULL due to cls_cgroup_init(). */
if (head) {
if (tcf_exts_get_net(&head->exts))
tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
else
__cls_cgroup_destroy(head);
}
}
static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
bool rtnl_held, struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
bool rtnl_held)
{
struct cls_cgroup_head *head = rtnl_dereference(tp->root);
if (arg->count < arg->skip)
goto skip;
if (!head)
return;
if (arg->fn(tp, head, arg) < 0) {
arg->stop = 1;
return;
}
skip:
arg->count++;
}
static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
{
struct cls_cgroup_head *head = rtnl_dereference(tp->root);
struct nlattr *nest;
t->tcm_handle = head->handle;
nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (tcf_exts_dump(skb, &head->exts) < 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) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
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,
.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");