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         struct rcu_work         rwork;
  27 };
  28
  29 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  30                                struct tcf_result *res)
  31 {
  32         struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
  33         u32 classid = task_get_classid(skb);
  34
  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, bool ovr)
  82 {
  83         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  84         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  85         struct cls_cgroup_head *new;
  86         int err;
  87
  88         if (!tca[TCA_OPTIONS])
  89                 return -EINVAL;
  90
  91         if (!head && !handle)
  92                 return -EINVAL;
  93
  94         if (head && handle != head->handle)
  95                 return -ENOENT;
  96
  97         new = kzalloc(sizeof(*head), GFP_KERNEL);
  98         if (!new)
  99                 return -ENOBUFS;
 100
 101         err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 102         if (err < 0)
 103                 goto errout;
 104         new->handle = handle;
 105         new->tp = tp;
 106         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 107                                cgroup_policy, NULL);
 108         if (err < 0)
 109                 goto errout;
 110
 111         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr);
 112         if (err < 0)
 113                 goto errout;
 114
 115         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 116         if (err < 0)
 117                 goto errout;
 118
 119         rcu_assign_pointer(tp->root, new);
 120         if (head) {
 121                 tcf_exts_get_net(&head->exts);
 122                 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 123         }
 124         return 0;
 125 errout:
 126         tcf_exts_destroy(&new->exts);
 127         kfree(new);
 128         return err;
 129 }
 130
 131 static void cls_cgroup_destroy(struct tcf_proto *tp)
 132 {
 133         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 134
 135         /* Head can still be NULL due to cls_cgroup_init(). */
 136         if (head) {
 137                 if (tcf_exts_get_net(&head->exts))
 138                         tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 139                 else
 140                         __cls_cgroup_destroy(head);
 141         }
 142 }
 143
 144 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)
 145 {
 146         return -EOPNOTSUPP;
 147 }
 148
 149 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 150 {
 151         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 152
 153         if (arg->count < arg->skip)
 154                 goto skip;
 155
 156         if (arg->fn(tp, head, arg) < 0) {
 157                 arg->stop = 1;
 158                 return;
 159         }
 160 skip:
 161         arg->count++;
 162 }
 163
 164 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 165                            struct sk_buff *skb, struct tcmsg *t)
 166 {
 167         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 168         struct nlattr *nest;
 169
 170         t->tcm_handle = head->handle;
 171
 172         nest = nla_nest_start(skb, TCA_OPTIONS);
 173         if (nest == NULL)
 174                 goto nla_put_failure;
 175
 176         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 177             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 178                 goto nla_put_failure;
 179
 180         nla_nest_end(skb, nest);
 181
 182         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 183                 goto nla_put_failure;
 184
 185         return skb->len;
 186
 187 nla_put_failure:
 188         nla_nest_cancel(skb, nest);
 189         return -1;
 190 }
 191
 192 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 193         .kind           =       "cgroup",
 194         .init           =       cls_cgroup_init,
 195         .change         =       cls_cgroup_change,
 196         .classify       =       cls_cgroup_classify,
 197         .destroy        =       cls_cgroup_destroy,
 198         .get            =       cls_cgroup_get,
 199         .delete         =       cls_cgroup_delete,
 200         .walk           =       cls_cgroup_walk,
 201         .dump           =       cls_cgroup_dump,
 202         .owner          =       THIS_MODULE,
 203 };
 204
 205 static int __init init_cgroup_cls(void)
 206 {
 207         return register_tcf_proto_ops(&cls_cgroup_ops);
 208 }
 209
 210 static void __exit exit_cgroup_cls(void)
 211 {
 212         unregister_tcf_proto_ops(&cls_cgroup_ops);
 213 }
 214
 215 module_init(init_cgroup_cls);
 216 module_exit(exit_cgroup_cls);
 217 MODULE_LICENSE("GPL");