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         struct rcu_head         rcu;
  38 };
  39
  40 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  41                           struct tcf_result *res)
  42 {
  43         int r;
  44         struct basic_head *head = rcu_dereference_bh(tp->root);
  45         struct basic_filter *f;
  46
  47         list_for_each_entry_rcu(f, &head->flist, link) {
  48                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  49                         continue;
  50                 *res = f->res;
  51                 r = tcf_exts_exec(skb, &f->exts, res);
  52                 if (r < 0)
  53                         continue;
  54                 return r;
  55         }
  56         return -1;
  57 }
  58
  59 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  60 {
  61         unsigned long l = 0UL;
  62         struct basic_head *head = rtnl_dereference(tp->root);
  63         struct basic_filter *f;
  64
  65         if (head == NULL)
  66                 return 0UL;
  67
  68         list_for_each_entry(f, &head->flist, link) {
  69                 if (f->handle == handle) {
  70                         l = (unsigned long) f;
  71                         break;
  72                 }
  73         }
  74
  75         return l;
  76 }
  77
  78 static int basic_init(struct tcf_proto *tp)
  79 {
  80         struct basic_head *head;
  81
  82         head = kzalloc(sizeof(*head), GFP_KERNEL);
  83         if (head == NULL)
  84                 return -ENOBUFS;
  85         INIT_LIST_HEAD(&head->flist);
  86         rcu_assign_pointer(tp->root, head);
  87         return 0;
  88 }
  89
  90 static void basic_delete_filter(struct rcu_head *head)
  91 {
  92         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
  93
  94         tcf_exts_destroy(&f->exts);
  95         tcf_em_tree_destroy(&f->ematches);
  96         kfree(f);
  97 }
  98
  99 static bool basic_destroy(struct tcf_proto *tp, bool force)
 100 {
 101         struct basic_head *head = rtnl_dereference(tp->root);
 102         struct basic_filter *f, *n;
 103
 104         if (!force && !list_empty(&head->flist))
 105                 return false;
 106
 107         list_for_each_entry_safe(f, n, &head->flist, link) {
 108                 list_del_rcu(&f->link);
 109                 tcf_unbind_filter(tp, &f->res);
 110                 call_rcu(&f->rcu, basic_delete_filter);
 111         }
 112         RCU_INIT_POINTER(tp->root, NULL);
 113         kfree_rcu(head, rcu);
 114         return true;
 115 }
 116
 117 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 118 {
 119         struct basic_filter *f = (struct basic_filter *) arg;
 120
 121         list_del_rcu(&f->link);
 122         tcf_unbind_filter(tp, &f->res);
 123         call_rcu(&f->rcu, basic_delete_filter);
 124         return 0;
 125 }
 126
 127 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 128         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 129         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 130 };
 131
 132 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 133                            struct basic_filter *f, unsigned long base,
 134                            struct nlattr **tb,
 135                            struct nlattr *est, bool ovr)
 136 {
 137         int err;
 138         struct tcf_exts e;
 139         struct tcf_ematch_tree t;
 140
 141         err = tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 142         if (err < 0)
 143                 return err;
 144         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 145         if (err < 0)
 146                 goto errout;
 147
 148         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 149         if (err < 0)
 150                 goto errout;
 151
 152         if (tb[TCA_BASIC_CLASSID]) {
 153                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 154                 tcf_bind_filter(tp, &f->res, base);
 155         }
 156
 157         tcf_exts_change(tp, &f->exts, &e);
 158         tcf_em_tree_change(tp, &f->ematches, &t);
 159         f->tp = tp;
 160
 161         return 0;
 162 errout:
 163         tcf_exts_destroy(&e);
 164         return err;
 165 }
 166
 167 static int basic_change(struct net *net, struct sk_buff *in_skb,
 168                         struct tcf_proto *tp, unsigned long base, u32 handle,
 169                         struct nlattr **tca, unsigned long *arg, bool ovr)
 170 {
 171         int err;
 172         struct basic_head *head = rtnl_dereference(tp->root);
 173         struct nlattr *tb[TCA_BASIC_MAX + 1];
 174         struct basic_filter *fold = (struct basic_filter *) *arg;
 175         struct basic_filter *fnew;
 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);
 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, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 195         if (err < 0)
 196                 goto errout;
 197
 198         err = -EINVAL;
 199         if (handle) {
 200                 fnew->handle = handle;
 201         } else if (fold) {
 202                 fnew->handle = fold->handle;
 203         } else {
 204                 unsigned int i = 0x80000000;
 205                 do {
 206                         if (++head->hgenerator == 0x7FFFFFFF)
 207                                 head->hgenerator = 1;
 208                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 209
 210                 if (i <= 0) {
 211                         pr_err("Insufficient number of handles\n");
 212                         goto errout;
 213                 }
 214
 215                 fnew->handle = head->hgenerator;
 216         }
 217
 218         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 219         if (err < 0)
 220                 goto errout;
 221
 222         *arg = (unsigned long)fnew;
 223
 224         if (fold) {
 225                 list_replace_rcu(&fold->link, &fnew->link);
 226                 tcf_unbind_filter(tp, &fold->res);
 227                 call_rcu(&fold->rcu, basic_delete_filter);
 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, (unsigned long) f, arg) < 0) {
 249                         arg->stop = 1;
 250                         break;
 251                 }
 252 skip:
 253                 arg->count++;
 254         }
 255 }
 256
 257 static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 258                       struct sk_buff *skb, struct tcmsg *t)
 259 {
 260         struct basic_filter *f = (struct basic_filter *) fh;
 261         struct nlattr *nest;
 262
 263         if (f == NULL)
 264                 return skb->len;
 265
 266         t->tcm_handle = f->handle;
 267
 268         nest = nla_nest_start(skb, TCA_OPTIONS);
 269         if (nest == NULL)
 270                 goto nla_put_failure;
 271
 272         if (f->res.classid &&
 273             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 274                 goto nla_put_failure;
 275
 276         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 277             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 278                 goto nla_put_failure;
 279
 280         nla_nest_end(skb, nest);
 281
 282         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 283                 goto nla_put_failure;
 284
 285         return skb->len;
 286
 287 nla_put_failure:
 288         nla_nest_cancel(skb, nest);
 289         return -1;
 290 }
 291
 292 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 293         .kind           =       "basic",
 294         .classify       =       basic_classify,
 295         .init           =       basic_init,
 296         .destroy        =       basic_destroy,
 297         .get            =       basic_get,
 298         .change         =       basic_change,
 299         .delete         =       basic_delete,
 300         .walk           =       basic_walk,
 301         .dump           =       basic_dump,
 302         .owner          =       THIS_MODULE,
 303 };
 304
 305 static int __init init_basic(void)
 306 {
 307         return register_tcf_proto_ops(&cls_basic_ops);
 308 }
 309
 310 static void __exit exit_basic(void)
 311 {
 312         unregister_tcf_proto_ops(&cls_basic_ops);
 313 }
 314
 315 module_init(init_basic)
 316 module_exit(exit_basic)
 317 MODULE_LICENSE("GPL");
 318