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 {
  96         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  97         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  98         struct cls_cgroup_head *new;
  99         int err;
 100
 101         if (!tca[TCA_OPTIONS])
 102                 return -EINVAL;
 103
 104         if (!head && !handle)
 105                 return -EINVAL;
 106
 107         if (head && handle != head->handle)
 108                 return -ENOENT;
 109
 110         new = kzalloc(sizeof(*head), GFP_KERNEL);
 111         if (!new)
 112                 return -ENOBUFS;
 113
 114         err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 115         if (err < 0)
 116                 goto errout;
 117         new->handle = handle;
 118         new->tp = tp;
 119         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 120                                cgroup_policy, NULL);
 121         if (err < 0)
 122                 goto errout;
 123
 124         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr);
 125         if (err < 0)
 126                 goto errout;
 127
 128         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 129         if (err < 0)
 130                 goto errout;
 131
 132         rcu_assign_pointer(tp->root, new);
 133         if (head) {
 134                 tcf_exts_get_net(&head->exts);
 135                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 136         }
 137         return 0;
 138 errout:
 139         tcf_exts_destroy(&new->exts);
 140         kfree(new);
 141         return err;
 142 }
 143
 144 static void cls_cgroup_destroy(struct tcf_proto *tp)
 145 {
 146         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 147
 148         /* Head can still be NULL due to cls_cgroup_init(). */
 149         if (head) {
 150                 if (tcf_exts_get_net(&head->exts))
 151                         call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 152                 else
 153                         __cls_cgroup_destroy(head);
 154         }
 155 }
 156
 157 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)
 158 {
 159         return -EOPNOTSUPP;
 160 }
 161
 162 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 163 {
 164         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 165
 166         if (arg->count < arg->skip)
 167                 goto skip;
 168
 169         if (arg->fn(tp, head, arg) < 0) {
 170                 arg->stop = 1;
 171                 return;
 172         }
 173 skip:
 174         arg->count++;
 175 }
 176
 177 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 178                            struct sk_buff *skb, struct tcmsg *t)
 179 {
 180         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 181         struct nlattr *nest;
 182
 183         t->tcm_handle = head->handle;
 184
 185         nest = nla_nest_start(skb, TCA_OPTIONS);
 186         if (nest == NULL)
 187                 goto nla_put_failure;
 188
 189         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 190             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 191                 goto nla_put_failure;
 192
 193         nla_nest_end(skb, nest);
 194
 195         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 196                 goto nla_put_failure;
 197
 198         return skb->len;
 199
 200 nla_put_failure:
 201         nla_nest_cancel(skb, nest);
 202         return -1;
 203 }
 204
 205 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 206         .kind           =       "cgroup",
 207         .init           =       cls_cgroup_init,
 208         .change         =       cls_cgroup_change,
 209         .classify       =       cls_cgroup_classify,
 210         .destroy        =       cls_cgroup_destroy,
 211         .get            =       cls_cgroup_get,
 212         .delete         =       cls_cgroup_delete,
 213         .walk           =       cls_cgroup_walk,
 214         .dump           =       cls_cgroup_dump,
 215         .owner          =       THIS_MODULE,
 216 };
 217
 218 static int __init init_cgroup_cls(void)
 219 {
 220         return register_tcf_proto_ops(&cls_cgroup_ops);
 221 }
 222
 223 static void __exit exit_cgroup_cls(void)
 224 {
 225         unregister_tcf_proto_ops(&cls_cgroup_ops);
 226 }
 227
 228 module_init(init_cgroup_cls);
 229 module_exit(exit_cgroup_cls);
 230 MODULE_LICENSE("GPL");