net/sched/cls_cgroup.c

   1 /*
   2  * net/sched/cls_cgroup.c       Control Group Classifier
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Thomas Graf <tgraf@suug.ch>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/rcupdate.h>
  16 #include <net/rtnetlink.h>
  17 #include <net/pkt_cls.h>
  18 #include <net/sock.h>
  19 #include <net/cls_cgroup.h>
  20
  21 struct cls_cgroup_head {
  22         u32                     handle;
  23         struct tcf_exts         exts;
  24         struct tcf_ematch_tree  ematches;
  25         struct tcf_proto        *tp;
  26         union {
  27                 struct work_struct      work;
  28                 struct rcu_head         rcu;
  29         };
  30 };
  31
  32 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  33                                struct tcf_result *res)
  34 {
  35         struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
  36         u32 classid = task_get_classid(skb);
  37
  38         if (!classid)
  39                 return -1;
  40         if (!tcf_em_tree_match(skb, &head->ematches, NULL))
  41                 return -1;
  42
  43         res->classid = classid;
  44         res->class = 0;
  45
  46         return tcf_exts_exec(skb, &head->exts, res);
  47 }
  48
  49 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
  50 {
  51         return NULL;
  52 }
  53
  54 static int cls_cgroup_init(struct tcf_proto *tp)
  55 {
  56         return 0;
  57 }
  58
  59 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
  60         [TCA_CGROUP_EMATCHES]   = { .type = NLA_NESTED },
  61 };
  62
  63 static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
  64 {
  65         tcf_exts_destroy(&head->exts);
  66         tcf_em_tree_destroy(&head->ematches);
  67         tcf_exts_put_net(&head->exts);
  68         kfree(head);
  69 }
  70
  71 static void cls_cgroup_destroy_work(struct work_struct *work)
  72 {
  73         struct cls_cgroup_head *head = container_of(work,
  74                                                     struct cls_cgroup_head,
  75                                                     work);
  76         rtnl_lock();
  77         __cls_cgroup_destroy(head);
  78         rtnl_unlock();
  79 }
  80
  81 static void cls_cgroup_destroy_rcu(struct rcu_head *root)
  82 {
  83         struct cls_cgroup_head *head = container_of(root,
  84                                                     struct cls_cgroup_head,
  85                                                     rcu);
  86
  87         INIT_WORK(&head->work, cls_cgroup_destroy_work);
  88         tcf_queue_work(&head->work);
  89 }
  90
  91 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
  92                              struct tcf_proto *tp, unsigned long base,
  93                              u32 handle, struct nlattr **tca,
  94                              void **arg, bool ovr,
  95                              struct netlink_ext_ack *extack)
  96 {
  97         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  98         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  99         struct cls_cgroup_head *new;
 100         int err;
 101
 102         if (!tca[TCA_OPTIONS])
 103                 return -EINVAL;
 104
 105         if (!head && !handle)
 106                 return -EINVAL;
 107
 108         if (head && handle != head->handle)
 109                 return -ENOENT;
 110
 111         new = kzalloc(sizeof(*head), GFP_KERNEL);
 112         if (!new)
 113                 return -ENOBUFS;
 114
 115         err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 116         if (err < 0)
 117                 goto errout;
 118         new->handle = handle;
 119         new->tp = tp;
 120         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 121                                cgroup_policy, NULL);
 122         if (err < 0)
 123                 goto errout;
 124
 125         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr,
 126                                 extack);
 127         if (err < 0)
 128                 goto errout;
 129
 130         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 131         if (err < 0)
 132                 goto errout;
 133
 134         rcu_assign_pointer(tp->root, new);
 135         if (head) {
 136                 tcf_exts_get_net(&head->exts);
 137                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 138         }
 139         return 0;
 140 errout:
 141         tcf_exts_destroy(&new->exts);
 142         kfree(new);
 143         return err;
 144 }
 145
 146 static void cls_cgroup_destroy(struct tcf_proto *tp,
 147                                struct netlink_ext_ack *extack)
 148 {
 149         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 150
 151         /* Head can still be NULL due to cls_cgroup_init(). */
 152         if (head) {
 153                 if (tcf_exts_get_net(&head->exts))
 154                         call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 155                 else
 156                         __cls_cgroup_destroy(head);
 157         }
 158 }
 159
 160 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
 161                              struct netlink_ext_ack *extack)
 162 {
 163         return -EOPNOTSUPP;
 164 }
 165
 166 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 167 {
 168         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 169
 170         if (arg->count < arg->skip)
 171                 goto skip;
 172
 173         if (arg->fn(tp, head, arg) < 0) {
 174                 arg->stop = 1;
 175                 return;
 176         }
 177 skip:
 178         arg->count++;
 179 }
 180
 181 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 182                            struct sk_buff *skb, struct tcmsg *t)
 183 {
 184         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 185         struct nlattr *nest;
 186
 187         t->tcm_handle = head->handle;
 188
 189         nest = nla_nest_start(skb, TCA_OPTIONS);
 190         if (nest == NULL)
 191                 goto nla_put_failure;
 192
 193         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 194             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 195                 goto nla_put_failure;
 196
 197         nla_nest_end(skb, nest);
 198
 199         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 200                 goto nla_put_failure;
 201
 202         return skb->len;
 203
 204 nla_put_failure:
 205         nla_nest_cancel(skb, nest);
 206         return -1;
 207 }
 208
 209 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 210         .kind           =       "cgroup",
 211         .init           =       cls_cgroup_init,
 212         .change         =       cls_cgroup_change,
 213         .classify       =       cls_cgroup_classify,
 214         .destroy        =       cls_cgroup_destroy,
 215         .get            =       cls_cgroup_get,
 216         .delete         =       cls_cgroup_delete,
 217         .walk           =       cls_cgroup_walk,
 218         .dump           =       cls_cgroup_dump,
 219         .owner          =       THIS_MODULE,
 220 };
 221
 222 static int __init init_cgroup_cls(void)
 223 {
 224         return register_tcf_proto_ops(&cls_cgroup_ops);
 225 }
 226
 227 static void __exit exit_cgroup_cls(void)
 228 {
 229         unregister_tcf_proto_ops(&cls_cgroup_ops);
 230 }
 231
 232 module_init(init_cgroup_cls);
 233 module_exit(exit_cgroup_cls);
 234 MODULE_LICENSE("GPL");