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/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
  23 struct basic_head
  24 {
  25         u32                     hgenerator;
  26         struct list_head        flist;
  27 };
  28
  29 struct 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
  38 static const struct tcf_ext_map basic_ext_map = {
  39         .action = TCA_BASIC_ACT,
  40         .police = TCA_BASIC_POLICE
  41 };
  42
  43 static 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
  62 static 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
  78 static void basic_put(struct tcf_proto *tp, unsigned long f)
  79 {
  80 }
  81
  82 static 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
  94 static 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
 103 static 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
 115 static 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
 132 static 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
 137 static 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;
 162 errout:
 163         tcf_exts_destroy(tp, &e);
 164         return err;
 165 }
 166
 167 static 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;
 222 errout:
 223         if (*arg == 0UL && f)
 224                 kfree(f);
 225
 226         return err;
 227 }
 228
 229 static 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                 }
 242 skip:
 243                 arg->count++;
 244         }
 245 }
 246
 247 static 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
 272 nla_put_failure:
 273         nla_nest_cancel(skb, nest);
 274         return -1;
 275 }
 276
 277 static 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
 291 static int __init init_basic(void)
 292 {
 293         return register_tcf_proto_ops(&cls_basic_ops);
 294 }
 295
 296 static void __exit exit_basic(void)
 297 {
 298         unregister_tcf_proto_ops(&cls_basic_ops);
 299 }
 300
 301 module_init(init_basic)
 302 module_exit(exit_basic)
 303 MODULE_LICENSE("GPL");
 304