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/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
  24struct basic_head {
  25        u32                     hgenerator;
  26        struct list_head        flist;
  27};
  28
  29struct 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
  37static const struct tcf_ext_map basic_ext_map = {
  38        .action = TCA_BASIC_ACT,
  39        .police = TCA_BASIC_POLICE
  40};
  41
  42static 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
  61static 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
  77static void basic_put(struct tcf_proto *tp, unsigned long f)
  78{
  79}
  80
  81static 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
  93static 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
 101static 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
 113static 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
 130static 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
 135static 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;
 160errout:
 161        tcf_exts_destroy(tp, &e);
 162        return err;
 163}
 164
 165static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 166                        struct nlattr **tca, unsigned long *arg)
 167{
 168        int err;
 169        struct basic_head *head = (struct basic_head *) tp->root;
 170        struct nlattr *tb[TCA_BASIC_MAX + 1];
 171        struct basic_filter *f = (struct basic_filter *) *arg;
 172
 173        if (tca[TCA_OPTIONS] == NULL)
 174                return -EINVAL;
 175
 176        err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 177                               basic_policy);
 178        if (err < 0)
 179                return err;
 180
 181        if (f != NULL) {
 182                if (handle && f->handle != handle)
 183                        return -EINVAL;
 184                return basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 185        }
 186
 187        err = -ENOBUFS;
 188        f = kzalloc(sizeof(*f), GFP_KERNEL);
 189        if (f == NULL)
 190                goto errout;
 191
 192        err = -EINVAL;
 193        if (handle)
 194                f->handle = handle;
 195        else {
 196                unsigned int i = 0x80000000;
 197                do {
 198                        if (++head->hgenerator == 0x7FFFFFFF)
 199                                head->hgenerator = 1;
 200                } while (--i > 0 && basic_get(tp, head->hgenerator));
 201
 202                if (i <= 0) {
 203                        pr_err("Insufficient number of handles\n");
 204                        goto errout;
 205                }
 206
 207                f->handle = head->hgenerator;
 208        }
 209
 210        err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 211        if (err < 0)
 212                goto errout;
 213
 214        tcf_tree_lock(tp);
 215        list_add(&f->link, &head->flist);
 216        tcf_tree_unlock(tp);
 217        *arg = (unsigned long) f;
 218
 219        return 0;
 220errout:
 221        if (*arg == 0UL && f)
 222                kfree(f);
 223
 224        return err;
 225}
 226
 227static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 228{
 229        struct basic_head *head = (struct basic_head *) tp->root;
 230        struct basic_filter *f;
 231
 232        list_for_each_entry(f, &head->flist, link) {
 233                if (arg->count < arg->skip)
 234                        goto skip;
 235
 236                if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 237                        arg->stop = 1;
 238                        break;
 239                }
 240skip:
 241                arg->count++;
 242        }
 243}
 244
 245static int basic_dump(struct tcf_proto *tp, unsigned long fh,
 246                      struct sk_buff *skb, struct tcmsg *t)
 247{
 248        struct basic_filter *f = (struct basic_filter *) fh;
 249        struct nlattr *nest;
 250
 251        if (f == NULL)
 252                return skb->len;
 253
 254        t->tcm_handle = f->handle;
 255
 256        nest = nla_nest_start(skb, TCA_OPTIONS);
 257        if (nest == NULL)
 258                goto nla_put_failure;
 259
 260        if (f->res.classid &&
 261            nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 262                goto nla_put_failure;
 263
 264        if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
 265            tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 266                goto nla_put_failure;
 267
 268        nla_nest_end(skb, nest);
 269
 270        if (tcf_exts_dump_stats(skb, &f->exts, &basic_ext_map) < 0)
 271                goto nla_put_failure;
 272
 273        return skb->len;
 274
 275nla_put_failure:
 276        nla_nest_cancel(skb, nest);
 277        return -1;
 278}
 279
 280static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 281        .kind           =       "basic",
 282        .classify       =       basic_classify,
 283        .init           =       basic_init,
 284        .destroy        =       basic_destroy,
 285        .get            =       basic_get,
 286        .put            =       basic_put,
 287        .change         =       basic_change,
 288        .delete         =       basic_delete,
 289        .walk           =       basic_walk,
 290        .dump           =       basic_dump,
 291        .owner          =       THIS_MODULE,
 292};
 293
 294static int __init init_basic(void)
 295{
 296        return register_tcf_proto_ops(&cls_basic_ops);
 297}
 298
 299static void __exit exit_basic(void)
 300{
 301        unregister_tcf_proto_ops(&cls_basic_ops);
 302}
 303
 304module_init(init_basic)
 305module_exit(exit_basic)
 306MODULE_LICENSE("GPL");
 307
 308
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