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_work(struct work_struct *work)
  64 {
  65         struct cls_cgroup_head *head = container_of(work,
  66                                                     struct cls_cgroup_head,
  67                                                     work);
  68         rtnl_lock();
  69         tcf_exts_destroy(&head->exts);
  70         tcf_em_tree_destroy(&head->ematches);
  71         kfree(head);
  72         rtnl_unlock();
  73 }
  74
  75 static void cls_cgroup_destroy_rcu(struct rcu_head *root)
  76 {
  77         struct cls_cgroup_head *head = container_of(root,
  78                                                     struct cls_cgroup_head,
  79                                                     rcu);
  80
  81         INIT_WORK(&head->work, cls_cgroup_destroy_work);
  82         tcf_queue_work(&head->work);
  83 }
  84
  85 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
  86                              struct tcf_proto *tp, unsigned long base,
  87                              u32 handle, struct nlattr **tca,
  88                              void **arg, bool ovr)
  89 {
  90         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  91         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  92         struct cls_cgroup_head *new;
  93         int err;
  94
  95         if (!tca[TCA_OPTIONS])
  96                 return -EINVAL;
  97
  98         if (!head && !handle)
  99                 return -EINVAL;
 100
 101         if (head && handle != head->handle)
 102                 return -ENOENT;
 103
 104         new = kzalloc(sizeof(*head), GFP_KERNEL);
 105         if (!new)
 106                 return -ENOBUFS;
 107
 108         err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 109         if (err < 0)
 110                 goto errout;
 111         new->handle = handle;
 112         new->tp = tp;
 113         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 114                                cgroup_policy, NULL);
 115         if (err < 0)
 116                 goto errout;
 117
 118         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr);
 119         if (err < 0)
 120                 goto errout;
 121
 122         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 123         if (err < 0)
 124                 goto errout;
 125
 126         rcu_assign_pointer(tp->root, new);
 127         if (head)
 128                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 129         return 0;
 130 errout:
 131         tcf_exts_destroy(&new->exts);
 132         kfree(new);
 133         return err;
 134 }
 135
 136 static void cls_cgroup_destroy(struct tcf_proto *tp)
 137 {
 138         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 139
 140         /* Head can still be NULL due to cls_cgroup_init(). */
 141         if (head)
 142                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 143 }
 144
 145 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last)
 146 {
 147         return -EOPNOTSUPP;
 148 }
 149
 150 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 151 {
 152         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 153
 154         if (arg->count < arg->skip)
 155                 goto skip;
 156
 157         if (arg->fn(tp, head, arg) < 0) {
 158                 arg->stop = 1;
 159                 return;
 160         }
 161 skip:
 162         arg->count++;
 163 }
 164
 165 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 166                            struct sk_buff *skb, struct tcmsg *t)
 167 {
 168         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 169         struct nlattr *nest;
 170
 171         t->tcm_handle = head->handle;
 172
 173         nest = nla_nest_start(skb, TCA_OPTIONS);
 174         if (nest == NULL)
 175                 goto nla_put_failure;
 176
 177         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 178             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 179                 goto nla_put_failure;
 180
 181         nla_nest_end(skb, nest);
 182
 183         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 184                 goto nla_put_failure;
 185
 186         return skb->len;
 187
 188 nla_put_failure:
 189         nla_nest_cancel(skb, nest);
 190         return -1;
 191 }
 192
 193 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 194         .kind           =       "cgroup",
 195         .init           =       cls_cgroup_init,
 196         .change         =       cls_cgroup_change,
 197         .classify       =       cls_cgroup_classify,
 198         .destroy        =       cls_cgroup_destroy,
 199         .get            =       cls_cgroup_get,
 200         .delete         =       cls_cgroup_delete,
 201         .walk           =       cls_cgroup_walk,
 202         .dump           =       cls_cgroup_dump,
 203         .owner          =       THIS_MODULE,
 204 };
 205
 206 static int __init init_cgroup_cls(void)
 207 {
 208         return register_tcf_proto_ops(&cls_cgroup_ops);
 209 }
 210
 211 static void __exit exit_cgroup_cls(void)
 212 {
 213         unregister_tcf_proto_ops(&cls_cgroup_ops);
 214 }
 215
 216 module_init(init_cgroup_cls);
 217 module_exit(exit_cgroup_cls);
 218 MODULE_LICENSE("GPL");