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_head         rcu;
  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 unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
  47 {
  48         return 0UL;
  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_rcu(struct rcu_head *root)
  61 {
  62         struct cls_cgroup_head *head = container_of(root,
  63                                                     struct cls_cgroup_head,
  64                                                     rcu);
  65
  66         tcf_exts_destroy(&head->exts);
  67         tcf_em_tree_destroy(&head->ematches);
  68         kfree(head);
  69 }
  70
  71 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
  72                              struct tcf_proto *tp, unsigned long base,
  73                              u32 handle, struct nlattr **tca,
  74                              unsigned long *arg, bool ovr)
  75 {
  76         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  77         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  78         struct cls_cgroup_head *new;
  79         struct tcf_ematch_tree t;
  80         struct tcf_exts e;
  81         int err;
  82
  83         if (!tca[TCA_OPTIONS])
  84                 return -EINVAL;
  85
  86         if (!head && !handle)
  87                 return -EINVAL;
  88
  89         if (head && handle != head->handle)
  90                 return -ENOENT;
  91
  92         new = kzalloc(sizeof(*head), GFP_KERNEL);
  93         if (!new)
  94                 return -ENOBUFS;
  95
  96         tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
  97         new->handle = handle;
  98         new->tp = tp;
  99         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 100                                cgroup_policy);
 101         if (err < 0)
 102                 goto errout;
 103
 104         tcf_exts_init(&e, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 105         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
 106         if (err < 0)
 107                 goto errout;
 108
 109         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
 110         if (err < 0) {
 111                 tcf_exts_destroy(&e);
 112                 goto errout;
 113         }
 114
 115         tcf_exts_change(tp, &new->exts, &e);
 116         tcf_em_tree_change(tp, &new->ematches, &t);
 117
 118         rcu_assign_pointer(tp->root, new);
 119         if (head)
 120                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 121         return 0;
 122 errout:
 123         kfree(new);
 124         return err;
 125 }
 126
 127 static bool cls_cgroup_destroy(struct tcf_proto *tp, bool force)
 128 {
 129         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 130
 131         if (!force)
 132                 return false;
 133         /* Head can still be NULL due to cls_cgroup_init(). */
 134         if (head)
 135                 call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
 136
 137         return true;
 138 }
 139
 140 static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
 141 {
 142         return -EOPNOTSUPP;
 143 }
 144
 145 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 146 {
 147         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 148
 149         if (arg->count < arg->skip)
 150                 goto skip;
 151
 152         if (arg->fn(tp, (unsigned long) head, arg) < 0) {
 153                 arg->stop = 1;
 154                 return;
 155         }
 156 skip:
 157         arg->count++;
 158 }
 159
 160 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 161                            struct sk_buff *skb, struct tcmsg *t)
 162 {
 163         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 164         struct nlattr *nest;
 165
 166         t->tcm_handle = head->handle;
 167
 168         nest = nla_nest_start(skb, TCA_OPTIONS);
 169         if (nest == NULL)
 170                 goto nla_put_failure;
 171
 172         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 173             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 174                 goto nla_put_failure;
 175
 176         nla_nest_end(skb, nest);
 177
 178         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 179                 goto nla_put_failure;
 180
 181         return skb->len;
 182
 183 nla_put_failure:
 184         nla_nest_cancel(skb, nest);
 185         return -1;
 186 }
 187
 188 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 189         .kind           =       "cgroup",
 190         .init           =       cls_cgroup_init,
 191         .change         =       cls_cgroup_change,
 192         .classify       =       cls_cgroup_classify,
 193         .destroy        =       cls_cgroup_destroy,
 194         .get            =       cls_cgroup_get,
 195         .delete         =       cls_cgroup_delete,
 196         .walk           =       cls_cgroup_walk,
 197         .dump           =       cls_cgroup_dump,
 198         .owner          =       THIS_MODULE,
 199 };
 200
 201 static int __init init_cgroup_cls(void)
 202 {
 203         return register_tcf_proto_ops(&cls_cgroup_ops);
 204 }
 205
 206 static void __exit exit_cgroup_cls(void)
 207 {
 208         unregister_tcf_proto_ops(&cls_cgroup_ops);
 209 }
 210
 211 module_init(init_cgroup_cls);
 212 module_exit(exit_cgroup_cls);
 213 MODULE_LICENSE("GPL");