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 <linux/idr.h>
  21 #include <net/netlink.h>
  22 #include <net/act_api.h>
  23 #include <net/pkt_cls.h>
  24
  25 struct basic_head {
  26         struct list_head        flist;
  27         struct idr              handle_idr;
  28         struct rcu_head         rcu;
  29 };
  30
  31 struct basic_filter {
  32         u32                     handle;
  33         struct tcf_exts         exts;
  34         struct tcf_ematch_tree  ematches;
  35         struct tcf_result       res;
  36         struct tcf_proto        *tp;
  37         struct list_head        link;
  38         union {
  39                 struct work_struct      work;
  40                 struct rcu_head         rcu;
  41         };
  42 };
  43
  44 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  45                           struct tcf_result *res)
  46 {
  47         int r;
  48         struct basic_head *head = rcu_dereference_bh(tp->root);
  49         struct basic_filter *f;
  50
  51         list_for_each_entry_rcu(f, &head->flist, link) {
  52                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  53                         continue;
  54                 *res = f->res;
  55                 r = tcf_exts_exec(skb, &f->exts, res);
  56                 if (r < 0)
  57                         continue;
  58                 return r;
  59         }
  60         return -1;
  61 }
  62
  63 static void *basic_get(struct tcf_proto *tp, u32 handle)
  64 {
  65         struct basic_head *head = rtnl_dereference(tp->root);
  66         struct basic_filter *f;
  67
  68         list_for_each_entry(f, &head->flist, link) {
  69                 if (f->handle == handle) {
  70                         return f;
  71                 }
  72         }
  73
  74         return NULL;
  75 }
  76
  77 static int basic_init(struct tcf_proto *tp)
  78 {
  79         struct basic_head *head;
  80
  81         head = kzalloc(sizeof(*head), GFP_KERNEL);
  82         if (head == NULL)
  83                 return -ENOBUFS;
  84         INIT_LIST_HEAD(&head->flist);
  85         idr_init(&head->handle_idr);
  86         rcu_assign_pointer(tp->root, head);
  87         return 0;
  88 }
  89
  90 static void __basic_delete_filter(struct basic_filter *f)
  91 {
  92         tcf_exts_destroy(&f->exts);
  93         tcf_em_tree_destroy(&f->ematches);
  94         tcf_exts_put_net(&f->exts);
  95         kfree(f);
  96 }
  97
  98 static void basic_delete_filter_work(struct work_struct *work)
  99 {
 100         struct basic_filter *f = container_of(work, struct basic_filter, work);
 101
 102         rtnl_lock();
 103         __basic_delete_filter(f);
 104         rtnl_unlock();
 105 }
 106
 107 static void basic_delete_filter(struct rcu_head *head)
 108 {
 109         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
 110
 111         INIT_WORK(&f->work, basic_delete_filter_work);
 112         tcf_queue_work(&f->work);
 113 }
 114
 115 static void basic_destroy(struct tcf_proto *tp)
 116 {
 117         struct basic_head *head = rtnl_dereference(tp->root);
 118         struct basic_filter *f, *n;
 119
 120         list_for_each_entry_safe(f, n, &head->flist, link) {
 121                 list_del_rcu(&f->link);
 122                 tcf_unbind_filter(tp, &f->res);
 123                 idr_remove_ext(&head->handle_idr, f->handle);
 124                 if (tcf_exts_get_net(&f->exts))
 125                         call_rcu(&f->rcu, basic_delete_filter);
 126                 else
 127                         __basic_delete_filter(f);
 128         }
 129         idr_destroy(&head->handle_idr);
 130         kfree_rcu(head, rcu);
 131 }
 132
 133 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last)
 134 {
 135         struct basic_head *head = rtnl_dereference(tp->root);
 136         struct basic_filter *f = arg;
 137
 138         list_del_rcu(&f->link);
 139         tcf_unbind_filter(tp, &f->res);
 140         idr_remove_ext(&head->handle_idr, f->handle);
 141         tcf_exts_get_net(&f->exts);
 142         call_rcu(&f->rcu, basic_delete_filter);
 143         *last = list_empty(&head->flist);
 144         return 0;
 145 }
 146
 147 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 148         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 149         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 150 };
 151
 152 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 153                            struct basic_filter *f, unsigned long base,
 154                            struct nlattr **tb,
 155                            struct nlattr *est, bool ovr)
 156 {
 157         int err;
 158
 159         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 160         if (err < 0)
 161                 return err;
 162
 163         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 164         if (err < 0)
 165                 return err;
 166
 167         if (tb[TCA_BASIC_CLASSID]) {
 168                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 169                 tcf_bind_filter(tp, &f->res, base);
 170         }
 171
 172         f->tp = tp;
 173         return 0;
 174 }
 175
 176 static int basic_change(struct net *net, struct sk_buff *in_skb,
 177                         struct tcf_proto *tp, unsigned long base, u32 handle,
 178                         struct nlattr **tca, void **arg, bool ovr)
 179 {
 180         int err;
 181         struct basic_head *head = rtnl_dereference(tp->root);
 182         struct nlattr *tb[TCA_BASIC_MAX + 1];
 183         struct basic_filter *fold = (struct basic_filter *) *arg;
 184         struct basic_filter *fnew;
 185         unsigned long idr_index;
 186
 187         if (tca[TCA_OPTIONS] == NULL)
 188                 return -EINVAL;
 189
 190         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 191                                basic_policy, NULL);
 192         if (err < 0)
 193                 return err;
 194
 195         if (fold != NULL) {
 196                 if (handle && fold->handle != handle)
 197                         return -EINVAL;
 198         }
 199
 200         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 201         if (!fnew)
 202                 return -ENOBUFS;
 203
 204         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 205         if (err < 0)
 206                 goto errout;
 207
 208         if (handle) {
 209                 fnew->handle = handle;
 210                 if (!fold) {
 211                         err = idr_alloc_ext(&head->handle_idr, fnew, &idr_index,
 212                                             handle, handle + 1, GFP_KERNEL);
 213                         if (err)
 214                                 goto errout;
 215                 }
 216         } else {
 217                 err = idr_alloc_ext(&head->handle_idr, fnew, &idr_index,
 218                                     1, 0x7FFFFFFF, GFP_KERNEL);
 219                 if (err)
 220                         goto errout;
 221                 fnew->handle = idr_index;
 222         }
 223
 224         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 225         if (err < 0) {
 226                 if (!fold)
 227                         idr_remove_ext(&head->handle_idr, fnew->handle);
 228                 goto errout;
 229         }
 230
 231         *arg = fnew;
 232
 233         if (fold) {
 234                 idr_replace_ext(&head->handle_idr, fnew, fnew->handle);
 235                 list_replace_rcu(&fold->link, &fnew->link);
 236                 tcf_unbind_filter(tp, &fold->res);
 237                 tcf_exts_get_net(&fold->exts);
 238                 call_rcu(&fold->rcu, basic_delete_filter);
 239         } else {
 240                 list_add_rcu(&fnew->link, &head->flist);
 241         }
 242
 243         return 0;
 244 errout:
 245         tcf_exts_destroy(&fnew->exts);
 246         kfree(fnew);
 247         return err;
 248 }
 249
 250 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 251 {
 252         struct basic_head *head = rtnl_dereference(tp->root);
 253         struct basic_filter *f;
 254
 255         list_for_each_entry(f, &head->flist, link) {
 256                 if (arg->count < arg->skip)
 257                         goto skip;
 258
 259                 if (arg->fn(tp, f, arg) < 0) {
 260                         arg->stop = 1;
 261                         break;
 262                 }
 263 skip:
 264                 arg->count++;
 265         }
 266 }
 267
 268 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 269 {
 270         struct basic_filter *f = fh;
 271
 272         if (f && f->res.classid == classid)
 273                 f->res.class = cl;
 274 }
 275
 276 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 277                       struct sk_buff *skb, struct tcmsg *t)
 278 {
 279         struct basic_filter *f = fh;
 280         struct nlattr *nest;
 281
 282         if (f == NULL)
 283                 return skb->len;
 284
 285         t->tcm_handle = f->handle;
 286
 287         nest = nla_nest_start(skb, TCA_OPTIONS);
 288         if (nest == NULL)
 289                 goto nla_put_failure;
 290
 291         if (f->res.classid &&
 292             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 293                 goto nla_put_failure;
 294
 295         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 296             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 297                 goto nla_put_failure;
 298
 299         nla_nest_end(skb, nest);
 300
 301         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 302                 goto nla_put_failure;
 303
 304         return skb->len;
 305
 306 nla_put_failure:
 307         nla_nest_cancel(skb, nest);
 308         return -1;
 309 }
 310
 311 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 312         .kind           =       "basic",
 313         .classify       =       basic_classify,
 314         .init           =       basic_init,
 315         .destroy        =       basic_destroy,
 316         .get            =       basic_get,
 317         .change         =       basic_change,
 318         .delete         =       basic_delete,
 319         .walk           =       basic_walk,
 320         .dump           =       basic_dump,
 321         .bind_class     =       basic_bind_class,
 322         .owner          =       THIS_MODULE,
 323 };
 324
 325 static int __init init_basic(void)
 326 {
 327         return register_tcf_proto_ops(&cls_basic_ops);
 328 }
 329
 330 static void __exit exit_basic(void)
 331 {
 332         unregister_tcf_proto_ops(&cls_basic_ops);
 333 }
 334
 335 module_init(init_basic)
 336 module_exit(exit_basic)
 337 MODULE_LICENSE("GPL");
 338