1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/cls_cgroup.c Control Group Classifier
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/skbuff.h>
11#include <linux/rcupdate.h>
12#include <net/rtnetlink.h>
13#include <net/pkt_cls.h>
14#include <net/sock.h>
15#include <net/cls_cgroup.h>
16#include <net/tc_wrapper.h>
17
18struct cls_cgroup_head {
19 u32 handle;
20 struct tcf_exts exts;
21 struct tcf_ematch_tree ematches;
22 struct tcf_proto *tp;
23 struct rcu_work rwork;
24};
25
26TC_INDIRECT_SCOPE int cls_cgroup_classify(struct sk_buff *skb,
27 const struct tcf_proto *tp,
28 struct tcf_result *res)
29{
30 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
31 u32 classid = task_get_classid(skb);
32
33 if (unlikely(!head))
34 return -1;
35 if (!classid)
36 return -1;
37 if (!tcf_em_tree_match(skb, tree: &head->ematches, NULL))
38 return -1;
39
40 res->classid = classid;
41 res->class = 0;
42
43 return tcf_exts_exec(skb, exts: &head->exts, res);
44}
45
46static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
47{
48 return NULL;
49}
50
51static int cls_cgroup_init(struct tcf_proto *tp)
52{
53 return 0;
54}
55
56static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
57 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
58};
59
60static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
61{
62 tcf_exts_destroy(exts: &head->exts);
63 tcf_em_tree_destroy(&head->ematches);
64 tcf_exts_put_net(exts: &head->exts);
65 kfree(objp: head);
66}
67
68static void cls_cgroup_destroy_work(struct work_struct *work)
69{
70 struct cls_cgroup_head *head = container_of(to_rcu_work(work),
71 struct cls_cgroup_head,
72 rwork);
73 rtnl_lock();
74 __cls_cgroup_destroy(head);
75 rtnl_unlock();
76}
77
78static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
79 struct tcf_proto *tp, unsigned long base,
80 u32 handle, struct nlattr **tca,
81 void **arg, u32 flags,
82 struct netlink_ext_ack *extack)
83{
84 struct nlattr *tb[TCA_CGROUP_MAX + 1];
85 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
86 struct cls_cgroup_head *new;
87 int err;
88
89 if (!tca[TCA_OPTIONS])
90 return -EINVAL;
91
92 if (!head && !handle)
93 return -EINVAL;
94
95 if (head && handle != head->handle)
96 return -ENOENT;
97
98 new = kzalloc(sizeof(*head), GFP_KERNEL);
99 if (!new)
100 return -ENOBUFS;
101
102 err = tcf_exts_init(exts: &new->exts, net, action: TCA_CGROUP_ACT, police: TCA_CGROUP_POLICE);
103 if (err < 0)
104 goto errout;
105 new->handle = handle;
106 new->tp = tp;
107 err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX,
108 nla: tca[TCA_OPTIONS], policy: cgroup_policy,
109 NULL);
110 if (err < 0)
111 goto errout;
112
113 err = tcf_exts_validate(net, tp, tb, rate_tlv: tca[TCA_RATE], exts: &new->exts, flags,
114 extack);
115 if (err < 0)
116 goto errout;
117
118 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
119 if (err < 0)
120 goto errout;
121
122 rcu_assign_pointer(tp->root, new);
123 if (head) {
124 tcf_exts_get_net(exts: &head->exts);
125 tcf_queue_work(rwork: &head->rwork, func: cls_cgroup_destroy_work);
126 }
127 return 0;
128errout:
129 tcf_exts_destroy(exts: &new->exts);
130 kfree(objp: new);
131 return err;
132}
133
134static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held,
135 struct netlink_ext_ack *extack)
136{
137 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
138
139 /* Head can still be NULL due to cls_cgroup_init(). */
140 if (head) {
141 if (tcf_exts_get_net(exts: &head->exts))
142 tcf_queue_work(rwork: &head->rwork, func: cls_cgroup_destroy_work);
143 else
144 __cls_cgroup_destroy(head);
145 }
146}
147
148static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
149 bool rtnl_held, struct netlink_ext_ack *extack)
150{
151 return -EOPNOTSUPP;
152}
153
154static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
155 bool rtnl_held)
156{
157 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
158
159 if (arg->count < arg->skip)
160 goto skip;
161
162 if (!head)
163 return;
164 if (arg->fn(tp, head, arg) < 0) {
165 arg->stop = 1;
166 return;
167 }
168skip:
169 arg->count++;
170}
171
172static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
173 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
174{
175 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
176 struct nlattr *nest;
177
178 t->tcm_handle = head->handle;
179
180 nest = nla_nest_start_noflag(skb, attrtype: TCA_OPTIONS);
181 if (nest == NULL)
182 goto nla_put_failure;
183
184 if (tcf_exts_dump(skb, exts: &head->exts) < 0 ||
185 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
186 goto nla_put_failure;
187
188 nla_nest_end(skb, start: nest);
189
190 if (tcf_exts_dump_stats(skb, exts: &head->exts) < 0)
191 goto nla_put_failure;
192
193 return skb->len;
194
195nla_put_failure:
196 nla_nest_cancel(skb, start: nest);
197 return -1;
198}
199
200static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
201 .kind = "cgroup",
202 .init = cls_cgroup_init,
203 .change = cls_cgroup_change,
204 .classify = cls_cgroup_classify,
205 .destroy = cls_cgroup_destroy,
206 .get = cls_cgroup_get,
207 .delete = cls_cgroup_delete,
208 .walk = cls_cgroup_walk,
209 .dump = cls_cgroup_dump,
210 .owner = THIS_MODULE,
211};
212MODULE_ALIAS_NET_CLS("cgroup");
213
214static int __init init_cgroup_cls(void)
215{
216 return register_tcf_proto_ops(ops: &cls_cgroup_ops);
217}
218
219static void __exit exit_cgroup_cls(void)
220{
221 unregister_tcf_proto_ops(ops: &cls_cgroup_ops);
222}
223
224module_init(init_cgroup_cls);
225module_exit(exit_cgroup_cls);
226MODULE_DESCRIPTION("TC cgroup classifier");
227MODULE_LICENSE("GPL");
228