xref: /openbmc/linux/net/sched/cls_cgroup.c (revision 9f3101dc)
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 
18 struct 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 
cls_cgroup_classify(struct sk_buff * skb,const struct tcf_proto * tp,struct tcf_result * res)26 TC_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, &head->ematches, NULL))
38 		return -1;
39 
40 	res->classid = classid;
41 	res->class = 0;
42 
43 	return tcf_exts_exec(skb, &head->exts, res);
44 }
45 
cls_cgroup_get(struct tcf_proto * tp,u32 handle)46 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
47 {
48 	return NULL;
49 }
50 
cls_cgroup_init(struct tcf_proto * tp)51 static int cls_cgroup_init(struct tcf_proto *tp)
52 {
53 	return 0;
54 }
55 
56 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
57 	[TCA_CGROUP_EMATCHES]	= { .type = NLA_NESTED },
58 };
59 
__cls_cgroup_destroy(struct cls_cgroup_head * head)60 static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
61 {
62 	tcf_exts_destroy(&head->exts);
63 	tcf_em_tree_destroy(&head->ematches);
64 	tcf_exts_put_net(&head->exts);
65 	kfree(head);
66 }
67 
cls_cgroup_destroy_work(struct work_struct * work)68 static 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 
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)78 static 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(&new->exts, net, TCA_CGROUP_ACT, 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 					  tca[TCA_OPTIONS], cgroup_policy,
109 					  NULL);
110 	if (err < 0)
111 		goto errout;
112 
113 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &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(&head->exts);
125 		tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
126 	}
127 	return 0;
128 errout:
129 	tcf_exts_destroy(&new->exts);
130 	kfree(new);
131 	return err;
132 }
133 
cls_cgroup_destroy(struct tcf_proto * tp,bool rtnl_held,struct netlink_ext_ack * extack)134 static 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(&head->exts))
142 			tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
143 		else
144 			__cls_cgroup_destroy(head);
145 	}
146 }
147 
cls_cgroup_delete(struct tcf_proto * tp,void * arg,bool * last,bool rtnl_held,struct netlink_ext_ack * extack)148 static 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 
cls_cgroup_walk(struct tcf_proto * tp,struct tcf_walker * arg,bool rtnl_held)154 static 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 	}
168 skip:
169 	arg->count++;
170 }
171 
cls_cgroup_dump(struct net * net,struct tcf_proto * tp,void * fh,struct sk_buff * skb,struct tcmsg * t,bool rtnl_held)172 static 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, TCA_OPTIONS);
181 	if (nest == NULL)
182 		goto nla_put_failure;
183 
184 	if (tcf_exts_dump(skb, &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, nest);
189 
190 	if (tcf_exts_dump_stats(skb, &head->exts) < 0)
191 		goto nla_put_failure;
192 
193 	return skb->len;
194 
195 nla_put_failure:
196 	nla_nest_cancel(skb, nest);
197 	return -1;
198 }
199 
200 static 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 };
212 
init_cgroup_cls(void)213 static int __init init_cgroup_cls(void)
214 {
215 	return register_tcf_proto_ops(&cls_cgroup_ops);
216 }
217 
exit_cgroup_cls(void)218 static void __exit exit_cgroup_cls(void)
219 {
220 	unregister_tcf_proto_ops(&cls_cgroup_ops);
221 }
222 
223 module_init(init_cgroup_cls);
224 module_exit(exit_cgroup_cls);
225 MODULE_LICENSE("GPL");
226