net/sched/cls_basic.c

   1 /*
   2  * net/sched/cls_basic.c        Basic Packet 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/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/skbuff.h>
  20 #include <net/netlink.h>
  21 #include <net/act_api.h>
  22 #include <net/pkt_cls.h>
  23
  24 struct basic_head {
  25         u32                     hgenerator;
  26         struct list_head        flist;
  27         struct rcu_head         rcu;
  28 };
  29
  30 struct basic_filter {
  31         u32                     handle;
  32         struct tcf_exts         exts;
  33         struct tcf_ematch_tree  ematches;
  34         struct tcf_result       res;
  35         struct tcf_proto        *tp;
  36         struct list_head        link;
  37         union {
  38                 struct work_struct      work;
  39                 struct rcu_head         rcu;
  40         };
  41 };
  42
  43 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  44                           struct tcf_result *res)
  45 {
  46         int r;
  47         struct basic_head *head = rcu_dereference_bh(tp->root);
  48         struct basic_filter *f;
  49
  50         list_for_each_entry_rcu(f, &head->flist, link) {
  51                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  52                         continue;
  53                 *res = f->res;
  54                 r = tcf_exts_exec(skb, &f->exts, res);
  55                 if (r < 0)
  56                         continue;
  57                 return r;
  58         }
  59         return -1;
  60 }
  61
  62 static void *basic_get(struct tcf_proto *tp, u32 handle)
  63 {
  64         struct basic_head *head = rtnl_dereference(tp->root);
  65         struct basic_filter *f;
  66
  67         list_for_each_entry(f, &head->flist, link) {
  68                 if (f->handle == handle) {
  69                         return f;
  70                 }
  71         }
  72
  73         return NULL;
  74 }
  75
  76 static int basic_init(struct tcf_proto *tp)
  77 {
  78         struct basic_head *head;
  79
  80         head = kzalloc(sizeof(*head), GFP_KERNEL);
  81         if (head == NULL)
  82                 return -ENOBUFS;
  83         INIT_LIST_HEAD(&head->flist);
  84         rcu_assign_pointer(tp->root, head);
  85         return 0;
  86 }
  87
  88 static void __basic_delete_filter(struct basic_filter *f)
  89 {
  90         tcf_exts_destroy(&f->exts);
  91         tcf_em_tree_destroy(&f->ematches);
  92         tcf_exts_put_net(&f->exts);
  93         kfree(f);
  94 }
  95
  96 static void basic_delete_filter_work(struct work_struct *work)
  97 {
  98         struct basic_filter *f = container_of(work, struct basic_filter, work);
  99
 100         rtnl_lock();
 101         __basic_delete_filter(f);
 102         rtnl_unlock();
 103 }
 104
 105 static void basic_delete_filter(struct rcu_head *head)
 106 {
 107         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
 108
 109         INIT_WORK(&f->work, basic_delete_filter_work);
 110         tcf_queue_work(&f->work);
 111 }
 112
 113 static void basic_destroy(struct tcf_proto *tp)
 114 {
 115         struct basic_head *head = rtnl_dereference(tp->root);
 116         struct basic_filter *f, *n;
 117
 118         list_for_each_entry_safe(f, n, &head->flist, link) {
 119                 list_del_rcu(&f->link);
 120                 tcf_unbind_filter(tp, &f->res);
 121                 if (tcf_exts_get_net(&f->exts))
 122                         call_rcu(&f->rcu, basic_delete_filter);
 123                 else
 124                         __basic_delete_filter(f);
 125         }
 126         kfree_rcu(head, rcu);
 127 }
 128
 129 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last)
 130 {
 131         struct basic_head *head = rtnl_dereference(tp->root);
 132         struct basic_filter *f = arg;
 133
 134         list_del_rcu(&f->link);
 135         tcf_unbind_filter(tp, &f->res);
 136         tcf_exts_get_net(&f->exts);
 137         call_rcu(&f->rcu, basic_delete_filter);
 138         *last = list_empty(&head->flist);
 139         return 0;
 140 }
 141
 142 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 143         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 144         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 145 };
 146
 147 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 148                            struct basic_filter *f, unsigned long base,
 149                            struct nlattr **tb,
 150                            struct nlattr *est, bool ovr)
 151 {
 152         int err;
 153
 154         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 155         if (err < 0)
 156                 return err;
 157
 158         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 159         if (err < 0)
 160                 return err;
 161
 162         if (tb[TCA_BASIC_CLASSID]) {
 163                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 164                 tcf_bind_filter(tp, &f->res, base);
 165         }
 166
 167         f->tp = tp;
 168         return 0;
 169 }
 170
 171 static int basic_change(struct net *net, struct sk_buff *in_skb,
 172                         struct tcf_proto *tp, unsigned long base, u32 handle,
 173                         struct nlattr **tca, void **arg, bool ovr)
 174 {
 175         int err;
 176         struct basic_head *head = rtnl_dereference(tp->root);
 177         struct nlattr *tb[TCA_BASIC_MAX + 1];
 178         struct basic_filter *fold = (struct basic_filter *) *arg;
 179         struct basic_filter *fnew;
 180
 181         if (tca[TCA_OPTIONS] == NULL)
 182                 return -EINVAL;
 183
 184         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 185                                basic_policy, NULL);
 186         if (err < 0)
 187                 return err;
 188
 189         if (fold != NULL) {
 190                 if (handle && fold->handle != handle)
 191                         return -EINVAL;
 192         }
 193
 194         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 195         if (!fnew)
 196                 return -ENOBUFS;
 197
 198         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 199         if (err < 0)
 200                 goto errout;
 201
 202         err = -EINVAL;
 203         if (handle) {
 204                 fnew->handle = handle;
 205         } else if (fold) {
 206                 fnew->handle = fold->handle;
 207         } else {
 208                 unsigned int i = 0x80000000;
 209                 do {
 210                         if (++head->hgenerator == 0x7FFFFFFF)
 211                                 head->hgenerator = 1;
 212                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 213
 214                 if (i <= 0) {
 215                         pr_err("Insufficient number of handles\n");
 216                         goto errout;
 217                 }
 218
 219                 fnew->handle = head->hgenerator;
 220         }
 221
 222         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 223         if (err < 0)
 224                 goto errout;
 225
 226         *arg = fnew;
 227
 228         if (fold) {
 229                 list_replace_rcu(&fold->link, &fnew->link);
 230                 tcf_unbind_filter(tp, &fold->res);
 231                 tcf_exts_get_net(&fold->exts);
 232                 call_rcu(&fold->rcu, basic_delete_filter);
 233         } else {
 234                 list_add_rcu(&fnew->link, &head->flist);
 235         }
 236
 237         return 0;
 238 errout:
 239         tcf_exts_destroy(&fnew->exts);
 240         kfree(fnew);
 241         return err;
 242 }
 243
 244 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 245 {
 246         struct basic_head *head = rtnl_dereference(tp->root);
 247         struct basic_filter *f;
 248
 249         list_for_each_entry(f, &head->flist, link) {
 250                 if (arg->count < arg->skip)
 251                         goto skip;
 252
 253                 if (arg->fn(tp, f, arg) < 0) {
 254                         arg->stop = 1;
 255                         break;
 256                 }
 257 skip:
 258                 arg->count++;
 259         }
 260 }
 261
 262 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 263 {
 264         struct basic_filter *f = fh;
 265
 266         if (f && f->res.classid == classid)
 267                 f->res.class = cl;
 268 }
 269
 270 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 271                       struct sk_buff *skb, struct tcmsg *t)
 272 {
 273         struct basic_filter *f = fh;
 274         struct nlattr *nest;
 275
 276         if (f == NULL)
 277                 return skb->len;
 278
 279         t->tcm_handle = f->handle;
 280
 281         nest = nla_nest_start(skb, TCA_OPTIONS);
 282         if (nest == NULL)
 283                 goto nla_put_failure;
 284
 285         if (f->res.classid &&
 286             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 287                 goto nla_put_failure;
 288
 289         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 290             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 291                 goto nla_put_failure;
 292
 293         nla_nest_end(skb, nest);
 294
 295         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 296                 goto nla_put_failure;
 297
 298         return skb->len;
 299
 300 nla_put_failure:
 301         nla_nest_cancel(skb, nest);
 302         return -1;
 303 }
 304
 305 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 306         .kind           =       "basic",
 307         .classify       =       basic_classify,
 308         .init           =       basic_init,
 309         .destroy        =       basic_destroy,
 310         .get            =       basic_get,
 311         .change         =       basic_change,
 312         .delete         =       basic_delete,
 313         .walk           =       basic_walk,
 314         .dump           =       basic_dump,
 315         .bind_class     =       basic_bind_class,
 316         .owner          =       THIS_MODULE,
 317 };
 318
 319 static int __init init_basic(void)
 320 {
 321         return register_tcf_proto_ops(&cls_basic_ops);
 322 }
 323
 324 static void __exit exit_basic(void)
 325 {
 326         unregister_tcf_proto_ops(&cls_basic_ops);
 327 }
 328
 329 module_init(init_basic)
 330 module_exit(exit_basic)
 331 MODULE_LICENSE("GPL");
 332