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, bool rtnl_held,
  82                              struct netlink_ext_ack *extack)
  83 {
  84         struct nlattr *tb[TCA_CGROUP_MAX + 1];
  85         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
  86         struct cls_cgroup_head *new;
  87         int err;
  88
  89         if (!tca[TCA_OPTIONS])
  90                 return -EINVAL;
  91
  92         if (!head && !handle)
  93                 return -EINVAL;
  94
  95         if (head && handle != head->handle)
  96                 return -ENOENT;
  97
  98         new = kzalloc(sizeof(*head), GFP_KERNEL);
  99         if (!new)
 100                 return -ENOBUFS;
 101
 102         err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
 103         if (err < 0)
 104                 goto errout;
 105         new->handle = handle;
 106         new->tp = tp;
 107         err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
 108                                cgroup_policy, NULL);
 109         if (err < 0)
 110                 goto errout;
 111
 112         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr,
 113                                 true, extack);
 114         if (err < 0)
 115                 goto errout;
 116
 117         err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
 118         if (err < 0)
 119                 goto errout;
 120
 121         rcu_assign_pointer(tp->root, new);
 122         if (head) {
 123                 tcf_exts_get_net(&head->exts);
 124                 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 125         }
 126         return 0;
 127 errout:
 128         tcf_exts_destroy(&new->exts);
 129         kfree(new);
 130         return err;
 131 }
 132
 133 static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held,
 134                                struct netlink_ext_ack *extack)
 135 {
 136         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 137
 138         /* Head can still be NULL due to cls_cgroup_init(). */
 139         if (head) {
 140                 if (tcf_exts_get_net(&head->exts))
 141                         tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
 142                 else
 143                         __cls_cgroup_destroy(head);
 144         }
 145 }
 146
 147 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
 148                              bool rtnl_held, struct netlink_ext_ack *extack)
 149 {
 150         return -EOPNOTSUPP;
 151 }
 152
 153 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 154                             bool rtnl_held)
 155 {
 156         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 157
 158         if (arg->count < arg->skip)
 159                 goto skip;
 160
 161         if (!head)
 162                 return;
 163         if (arg->fn(tp, head, arg) < 0) {
 164                 arg->stop = 1;
 165                 return;
 166         }
 167 skip:
 168         arg->count++;
 169 }
 170
 171 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
 172                            struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 173 {
 174         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 175         struct nlattr *nest;
 176
 177         t->tcm_handle = head->handle;
 178
 179         nest = nla_nest_start(skb, TCA_OPTIONS);
 180         if (nest == NULL)
 181                 goto nla_put_failure;
 182
 183         if (tcf_exts_dump(skb, &head->exts) < 0 ||
 184             tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
 185                 goto nla_put_failure;
 186
 187         nla_nest_end(skb, nest);
 188
 189         if (tcf_exts_dump_stats(skb, &head->exts) < 0)
 190                 goto nla_put_failure;
 191
 192         return skb->len;
 193
 194 nla_put_failure:
 195         nla_nest_cancel(skb, nest);
 196         return -1;
 197 }
 198
 199 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
 200         .kind           =       "cgroup",
 201         .init           =       cls_cgroup_init,
 202         .change         =       cls_cgroup_change,
 203         .classify       =       cls_cgroup_classify,
 204         .destroy        =       cls_cgroup_destroy,
 205         .get            =       cls_cgroup_get,
 206         .delete         =       cls_cgroup_delete,
 207         .walk           =       cls_cgroup_walk,
 208         .dump           =       cls_cgroup_dump,
 209         .owner          =       THIS_MODULE,
 210 };
 211
 212 static int __init init_cgroup_cls(void)
 213 {
 214         return register_tcf_proto_ops(&cls_cgroup_ops);
 215 }
 216
 217 static void __exit exit_cgroup_cls(void)
 218 {
 219         unregister_tcf_proto_ops(&cls_cgroup_ops);
 220 }
 221
 222 module_init(init_cgroup_cls);
 223 module_exit(exit_cgroup_cls);
 224 MODULE_LICENSE("GPL");