net/sched/cls_cgroup.c

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