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