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