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 #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
  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
  46 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
  47 {
  48         return NULL;
  49 }
  50
  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
  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
  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
  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
 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
 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
 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
 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 MODULE_ALIAS_NET_CLS("cgroup");
 213
 214 static int __init init_cgroup_cls(void)
 215 {
 216         return register_tcf_proto_ops(&cls_cgroup_ops);
 217 }
 218
 219 static void __exit exit_cgroup_cls(void)
 220 {
 221         unregister_tcf_proto_ops(&cls_cgroup_ops);
 222 }
 223
 224 module_init(init_cgroup_cls);
 225 module_exit(exit_cgroup_cls);
 226 MODULE_DESCRIPTION("TC cgroup classifier");
 227 MODULE_LICENSE("GPL");