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, struct netlink_ext_ack *extack)
 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(&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                         struct netlink_ext_ack *extack)
 125 {
 126         struct basic_head *head = rtnl_dereference(tp->root);
 127         struct basic_filter *f = arg;
 128
 129         list_del_rcu(&f->link);
 130         tcf_unbind_filter(tp, &f->res);
 131         idr_remove(&head->handle_idr, f->handle);
 132         tcf_exts_get_net(&f->exts);
 133         tcf_queue_work(&f->rwork, basic_delete_filter_work);
 134         *last = list_empty(&head->flist);
 135         return 0;
 136 }
 137
 138 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 139         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 140         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 141 };
 142
 143 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 144                            struct basic_filter *f, unsigned long base,
 145                            struct nlattr **tb,
 146                            struct nlattr *est, bool ovr,
 147                            struct netlink_ext_ack *extack)
 148 {
 149         int err;
 150
 151         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, extack);
 152         if (err < 0)
 153                 return err;
 154
 155         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 156         if (err < 0)
 157                 return err;
 158
 159         if (tb[TCA_BASIC_CLASSID]) {
 160                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 161                 tcf_bind_filter(tp, &f->res, base);
 162         }
 163
 164         f->tp = tp;
 165         return 0;
 166 }
 167
 168 static int basic_change(struct net *net, struct sk_buff *in_skb,
 169                         struct tcf_proto *tp, unsigned long base, u32 handle,
 170                         struct nlattr **tca, void **arg, bool ovr,
 171                         struct netlink_ext_ack *extack)
 172 {
 173         int err;
 174         struct basic_head *head = rtnl_dereference(tp->root);
 175         struct nlattr *tb[TCA_BASIC_MAX + 1];
 176         struct basic_filter *fold = (struct basic_filter *) *arg;
 177         struct basic_filter *fnew;
 178
 179         if (tca[TCA_OPTIONS] == NULL)
 180                 return -EINVAL;
 181
 182         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 183                                basic_policy, NULL);
 184         if (err < 0)
 185                 return err;
 186
 187         if (fold != NULL) {
 188                 if (handle && fold->handle != handle)
 189                         return -EINVAL;
 190         }
 191
 192         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 193         if (!fnew)
 194                 return -ENOBUFS;
 195
 196         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 197         if (err < 0)
 198                 goto errout;
 199
 200         if (!handle) {
 201                 handle = 1;
 202                 err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
 203                                     INT_MAX, GFP_KERNEL);
 204         } else if (!fold) {
 205                 err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
 206                                     handle, GFP_KERNEL);
 207         }
 208         if (err)
 209                 goto errout;
 210         fnew->handle = handle;
 211
 212         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr,
 213                               extack);
 214         if (err < 0) {
 215                 if (!fold)
 216                         idr_remove(&head->handle_idr, fnew->handle);
 217                 goto errout;
 218         }
 219
 220         *arg = fnew;
 221
 222         if (fold) {
 223                 idr_replace(&head->handle_idr, fnew, fnew->handle);
 224                 list_replace_rcu(&fold->link, &fnew->link);
 225                 tcf_unbind_filter(tp, &fold->res);
 226                 tcf_exts_get_net(&fold->exts);
 227                 tcf_queue_work(&fold->rwork, basic_delete_filter_work);
 228         } else {
 229                 list_add_rcu(&fnew->link, &head->flist);
 230         }
 231
 232         return 0;
 233 errout:
 234         tcf_exts_destroy(&fnew->exts);
 235         kfree(fnew);
 236         return err;
 237 }
 238
 239 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 240 {
 241         struct basic_head *head = rtnl_dereference(tp->root);
 242         struct basic_filter *f;
 243
 244         list_for_each_entry(f, &head->flist, link) {
 245                 if (arg->count < arg->skip)
 246                         goto skip;
 247
 248                 if (arg->fn(tp, f, arg) < 0) {
 249                         arg->stop = 1;
 250                         break;
 251                 }
 252 skip:
 253                 arg->count++;
 254         }
 255 }
 256
 257 static void basic_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
 258                              unsigned long base)
 259 {
 260         struct basic_filter *f = fh;
 261
 262         if (f && f->res.classid == classid) {
 263                 if (cl)
 264                         __tcf_bind_filter(q, &f->res, base);
 265                 else
 266                         __tcf_unbind_filter(q, &f->res);
 267         }
 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");