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 (unlikely(!head))
  36                 return -1;
  37         if (!classid)
  38                 return -1;
  39         if (!tcf_em_tree_match(skb, &head->ematches, NULL))
  40                 return -1;
  41
  42         res->classid = classid;
  43         res->class = 0;
  44
  45         return tcf_exts_exec(skb, &head->exts, res);
  46 }
  47
  48 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
  49 {
  50         return NULL;
  51 }
  52
  53 static int cls_cgroup_init(struct tcf_proto *tp)
  54 {
  55         return 0;
  56 }
  57
  58 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
  59         [TCA_CGROUP_EMATCHES]   = { .type = NLA_NESTED },
  60 };
  61
  62 static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
  63 {
  64         tcf_exts_destroy(&head->exts);
  65         tcf_em_tree_destroy(&head->ematches);
  66         tcf_exts_put_net(&head->exts);
  67         kfree(head);
  68 }
  69
  70 static void cls_cgroup_destroy_work(struct work_struct *work)
  71 {
  72         struct cls_cgroup_head *head = container_of(to_rcu_work(work),
  73                                                     struct cls_cgroup_head,
  74                                                     rwork);
  75         rtnl_lock();
  76         __cls_cgroup_destroy(head);
  77         rtnl_unlock();
  78 }
  79
  80 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
  81                              struct tcf_proto *tp, unsigned long base,
  82                              u32 handle, struct nlattr **tca,
  83                              void **arg, bool ovr, bool rtnl_held,
  84                              struct netlink_ext_ack *extack)
  85 {
  86         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  87         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  88         struct cls_cgroup_head *new;
  89         int err;
  90
  91         if (!tca[TCA_OPTIONS])
  92                 return -EINVAL;
  93
  94         if (!head && !handle)
  95                 return -EINVAL;
  96
  97         if (head && handle != head->handle)
  98                 return -ENOENT;
  99
 100         new = kzalloc(sizeof(*head), GFP_KERNEL);
 101         if (!new)
 102                 return -ENOBUFS;
 103
 104         err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 105         if (err < 0)
 106                 goto errout;
 107         new->handle = handle;
 108         new->tp = tp;
 109         err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX,
 110                                           tca[TCA_OPTIONS], cgroup_policy,
 111                                           NULL);
 112         if (err < 0)
 113                 goto errout;
 114
 115         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr,
 116                                 true, extack);
 117         if (err < 0)
 118                 goto errout;
 119
 120         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 121         if (err < 0)
 122                 goto errout;
 123
 124         rcu_assign_pointer(tp->root, new);
 125         if (head) {
 126                 tcf_exts_get_net(&head->exts);
 127                 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 128         }
 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, bool rtnl_held,
 137                                struct netlink_ext_ack *extack)
 138 {
 139         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 140
 141         /* Head can still be NULL due to cls_cgroup_init(). */
 142         if (head) {
 143                 if (tcf_exts_get_net(&head->exts))
 144                         tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 145                 else
 146                         __cls_cgroup_destroy(head);
 147         }
 148 }
 149
 150 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
 151                              bool rtnl_held, struct netlink_ext_ack *extack)
 152 {
 153         return -EOPNOTSUPP;
 154 }
 155
 156 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 157                             bool rtnl_held)
 158 {
 159         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 160
 161         if (arg->count < arg->skip)
 162                 goto skip;
 163
 164         if (!head)
 165                 return;
 166         if (arg->fn(tp, head, arg) < 0) {
 167                 arg->stop = 1;
 168                 return;
 169         }
 170 skip:
 171         arg->count++;
 172 }
 173
 174 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 175                            struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 176 {
 177         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 178         struct nlattr *nest;
 179
 180         t->tcm_handle = head->handle;
 181
 182         nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
 183         if (nest == NULL)
 184                 goto nla_put_failure;
 185
 186         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 187             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 188                 goto nla_put_failure;
 189
 190         nla_nest_end(skb, nest);
 191
 192         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 193                 goto nla_put_failure;
 194
 195         return skb->len;
 196
 197 nla_put_failure:
 198         nla_nest_cancel(skb, nest);
 199         return -1;
 200 }
 201
 202 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 203         .kind           =       "cgroup",
 204         .init           =       cls_cgroup_init,
 205         .change         =       cls_cgroup_change,
 206         .classify       =       cls_cgroup_classify,
 207         .destroy        =       cls_cgroup_destroy,
 208         .get            =       cls_cgroup_get,
 209         .delete         =       cls_cgroup_delete,
 210         .walk           =       cls_cgroup_walk,
 211         .dump           =       cls_cgroup_dump,
 212         .owner          =       THIS_MODULE,
 213 };
 214
 215 static int __init init_cgroup_cls(void)
 216 {
 217         return register_tcf_proto_ops(&cls_cgroup_ops);
 218 }
 219
 220 static void __exit exit_cgroup_cls(void)
 221 {
 222         unregister_tcf_proto_ops(&cls_cgroup_ops);
 223 }
 224
 225 module_init(init_cgroup_cls);
 226 module_exit(exit_cgroup_cls);
 227 MODULE_LICENSE("GPL");