linux/net/sched/cls_basic.c
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   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/types.h>
  14#include <linux/kernel.h>
  15#include <linux/string.h>
  16#include <linux/errno.h>
  17#include <linux/rtnetlink.h>
  18#include <linux/skbuff.h>
  19#include <net/netlink.h>
  20#include <net/act_api.h>
  21#include <net/pkt_cls.h>
  22
  23struct basic_head
  24{
  25        u32                     hgenerator;
  26        struct list_head        flist;
  27};
  28
  29struct basic_filter
  30{
  31        u32                     handle;
  32        struct tcf_exts         exts;
  33        struct tcf_ematch_tree  ematches;
  34        struct tcf_result       res;
  35        struct list_head        link;
  36};
  37
  38static const struct tcf_ext_map basic_ext_map = {
  39        .action = TCA_BASIC_ACT,
  40        .police = TCA_BASIC_POLICE
  41};
  42
  43static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
  44                          struct tcf_result *res)
  45{
  46        int r;
  47        struct basic_head *head = (struct basic_head *) tp->root;
  48        struct basic_filter *f;
  49
  50        list_for_each_entry(f, &head->flist, link) {
  51                if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  52                        continue;
  53                *res = f->res;
  54                r = tcf_exts_exec(skb, &f->exts, res);
  55                if (r < 0)
  56                        continue;
  57                return r;
  58        }
  59        return -1;
  60}
  61
  62static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  63{
  64        unsigned long l = 0UL;
  65        struct basic_head *head = (struct basic_head *) tp->root;
  66        struct basic_filter *f;
  67
  68        if (head == NULL)
  69                return 0UL;
  70
  71        list_for_each_entry(f, &head->flist, link)
  72                if (f->handle == handle)
  73                        l = (unsigned long) f;
  74
  75        return l;
  76}
  77
  78static void basic_put(struct tcf_proto *tp, unsigned long f)
  79{
  80}
  81
  82static int basic_init(struct tcf_proto *tp)
  83{
  84        struct basic_head *head;
  85
  86        head = kzalloc(sizeof(*head), GFP_KERNEL);
  87        if (head == NULL)
  88                return -ENOBUFS;
  89        INIT_LIST_HEAD(&head->flist);
  90        tp->root = head;
  91        return 0;
  92}
  93
  94static inline void basic_delete_filter(struct tcf_proto *tp,
  95                                       struct basic_filter *f)
  96{
  97        tcf_unbind_filter(tp, &f->res);
  98        tcf_exts_destroy(tp, &f->exts);
  99        tcf_em_tree_destroy(tp, &f->ematches);
 100        kfree(f);
 101}
 102
 103static void basic_destroy(struct tcf_proto *tp)
 104{
 105        struct basic_head *head = tp->root;
 106        struct basic_filter *f, *n;
 107
 108        list_for_each_entry_safe(f, n, &head->flist, link) {
 109                list_del(&f->link);
 110                basic_delete_filter(tp, f);
 111        }
 112        kfree(head);
 113}
 114
 115static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 116{
 117        struct basic_head *head = (struct basic_head *) tp->root;
 118        struct basic_filter *t, *f = (struct basic_filter *) arg;
 119
 120        list_for_each_entry(t, &head->flist, link)
 121                if (t == f) {
 122                        tcf_tree_lock(tp);
 123                        list_del(&t->link);
 124                        tcf_tree_unlock(tp);
 125                        basic_delete_filter(tp, t);
 126                        return 0;
 127                }
 128
 129        return -ENOENT;
 130}
 131
 132static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 133        [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 134        [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 135};
 136
 137static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
 138                                  unsigned long base, struct nlattr **tb,
 139                                  struct nlattr *est)
 140{
 141        int err = -EINVAL;
 142        struct tcf_exts e;
 143        struct tcf_ematch_tree t;
 144
 145        err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
 146        if (err < 0)
 147                return err;
 148
 149        err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 150        if (err < 0)
 151                goto errout;
 152
 153        if (tb[TCA_BASIC_CLASSID]) {
 154                f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 155                tcf_bind_filter(tp, &f->res, base);
 156        }
 157
 158        tcf_exts_change(tp, &f->exts, &e);
 159        tcf_em_tree_change(tp, &f->ematches, &t);
 160
 161        return 0;
 162errout:
 163        tcf_exts_destroy(tp, &e);
 164        return err;
 165}
 166
 167static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 168                        struct nlattr **tca, unsigned long *arg)
 169{
 170        int err;
 171        struct basic_head *head = (struct basic_head *) tp->root;
 172        struct nlattr *tb[TCA_BASIC_MAX + 1];
 173        struct basic_filter *f = (struct basic_filter *) *arg;
 174
 175        if (tca[TCA_OPTIONS] == NULL)
 176                return -EINVAL;
 177
 178        err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 179                               basic_policy);
 180        if (err < 0)
 181                return err;
 182
 183        if (f != NULL) {
 184                if (handle && f->handle != handle)
 185                        return -EINVAL;
 186                return basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 187        }
 188
 189        err = -ENOBUFS;
 190        f = kzalloc(sizeof(*f), GFP_KERNEL);
 191        if (f == NULL)
 192                goto errout;
 193
 194        err = -EINVAL;
 195        if (handle)
 196                f->handle = handle;
 197        else {
 198                unsigned int i = 0x80000000;
 199                do {
 200                        if (++head->hgenerator == 0x7FFFFFFF)
 201                                head->hgenerator = 1;
 202                } while (--i > 0 && basic_get(tp, head->hgenerator));
 203
 204                if (i <= 0) {
 205                        printk(KERN_ERR "Insufficient number of handles\n");
 206                        goto errout;
 207                }
 208
 209                f->handle = head->hgenerator;
 210        }
 211
 212        err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 213        if (err < 0)
 214                goto errout;
 215
 216        tcf_tree_lock(tp);
 217        list_add(&f->link, &head->flist);
 218        tcf_tree_unlock(tp);
 219        *arg = (unsigned long) f;
 220
 221        return 0;
 222errout:
 223        if (*arg == 0UL && f)
 224                kfree(f);
 225
 226        return err;
 227}
 228
 229static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 230{
 231        struct basic_head *head = (struct basic_head *) tp->root;
 232        struct basic_filter *f;
 233
 234        list_for_each_entry(f, &head->flist, link) {
 235                if (arg->count < arg->skip)
 236                        goto skip;
 237
 238                if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 239                        arg->stop = 1;
 240                        break;
 241                }
 242skip:
 243                arg->count++;
 244        }
 245}
 246
 247static int basic_dump(struct tcf_proto *tp, unsigned long fh,
 248                      struct sk_buff *skb, struct tcmsg *t)
 249{
 250        struct basic_filter *f = (struct basic_filter *) fh;
 251        struct nlattr *nest;
 252
 253        if (f == NULL)
 254                return skb->len;
 255
 256        t->tcm_handle = f->handle;
 257
 258        nest = nla_nest_start(skb, TCA_OPTIONS);
 259        if (nest == NULL)
 260                goto nla_put_failure;
 261
 262        if (f->res.classid)
 263                NLA_PUT_U32(skb, TCA_BASIC_CLASSID, f->res.classid);
 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        return skb->len;
 271
 272nla_put_failure:
 273        nla_nest_cancel(skb, nest);
 274        return -1;
 275}
 276
 277static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 278        .kind           =       "basic",
 279        .classify       =       basic_classify,
 280        .init           =       basic_init,
 281        .destroy        =       basic_destroy,
 282        .get            =       basic_get,
 283        .put            =       basic_put,
 284        .change         =       basic_change,
 285        .delete         =       basic_delete,
 286        .walk           =       basic_walk,
 287        .dump           =       basic_dump,
 288        .owner          =       THIS_MODULE,
 289};
 290
 291static int __init init_basic(void)
 292{
 293        return register_tcf_proto_ops(&cls_basic_ops);
 294}
 295
 296static void __exit exit_basic(void)
 297{
 298        unregister_tcf_proto_ops(&cls_basic_ops);
 299}
 300
 301module_init(init_basic)
 302module_exit(exit_basic)
 303MODULE_LICENSE("GPL");
 304
 305