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 {
  26         u32                     hgenerator;
  27         struct list_head        flist;
  28 };
  29
  30 struct basic_filter
  31 {
  32         u32                     handle;
  33         struct tcf_exts         exts;
  34         struct tcf_ematch_tree  ematches;
  35         struct tcf_result       res;
  36         struct list_head        link;
  37 };
  38
  39 static const struct tcf_ext_map basic_ext_map = {
  40         .action = TCA_BASIC_ACT,
  41         .police = TCA_BASIC_POLICE
  42 };
  43
  44 static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
  45                           struct tcf_result *res)
  46 {
  47         int r;
  48         struct basic_head *head = (struct basic_head *) tp->root;
  49         struct basic_filter *f;
  50
  51         list_for_each_entry(f, &head->flist, link) {
  52                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  53                         continue;
  54                 *res = f->res;
  55                 r = tcf_exts_exec(skb, &f->exts, res);
  56                 if (r < 0)
  57                         continue;
  58                 return r;
  59         }
  60         return -1;
  61 }
  62
  63 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  64 {
  65         unsigned long l = 0UL;
  66         struct basic_head *head = (struct basic_head *) tp->root;
  67         struct basic_filter *f;
  68
  69         if (head == NULL)
  70                 return 0UL;
  71
  72         list_for_each_entry(f, &head->flist, link)
  73                 if (f->handle == handle)
  74                         l = (unsigned long) f;
  75
  76         return l;
  77 }
  78
  79 static void basic_put(struct tcf_proto *tp, unsigned long f)
  80 {
  81 }
  82
  83 static int basic_init(struct tcf_proto *tp)
  84 {
  85         struct basic_head *head;
  86
  87         head = kzalloc(sizeof(*head), GFP_KERNEL);
  88         if (head == NULL)
  89                 return -ENOBUFS;
  90         INIT_LIST_HEAD(&head->flist);
  91         tp->root = head;
  92         return 0;
  93 }
  94
  95 static inline void basic_delete_filter(struct tcf_proto *tp,
  96                                        struct basic_filter *f)
  97 {
  98         tcf_unbind_filter(tp, &f->res);
  99         tcf_exts_destroy(tp, &f->exts);
 100         tcf_em_tree_destroy(tp, &f->ematches);
 101         kfree(f);
 102 }
 103
 104 static void basic_destroy(struct tcf_proto *tp)
 105 {
 106         struct basic_head *head = tp->root;
 107         struct basic_filter *f, *n;
 108
 109         list_for_each_entry_safe(f, n, &head->flist, link) {
 110                 list_del(&f->link);
 111                 basic_delete_filter(tp, f);
 112         }
 113         kfree(head);
 114 }
 115
 116 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 117 {
 118         struct basic_head *head = (struct basic_head *) tp->root;
 119         struct basic_filter *t, *f = (struct basic_filter *) arg;
 120
 121         list_for_each_entry(t, &head->flist, link)
 122                 if (t == f) {
 123                         tcf_tree_lock(tp);
 124                         list_del(&t->link);
 125                         tcf_tree_unlock(tp);
 126                         basic_delete_filter(tp, t);
 127                         return 0;
 128                 }
 129
 130         return -ENOENT;
 131 }
 132
 133 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 134         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 135         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 136 };
 137
 138 static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
 139                                   unsigned long base, struct nlattr **tb,
 140                                   struct nlattr *est)
 141 {
 142         int err = -EINVAL;
 143         struct tcf_exts e;
 144         struct tcf_ematch_tree t;
 145
 146         err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
 147         if (err < 0)
 148                 return err;
 149
 150         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 151         if (err < 0)
 152                 goto errout;
 153
 154         if (tb[TCA_BASIC_CLASSID]) {
 155                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 156                 tcf_bind_filter(tp, &f->res, base);
 157         }
 158
 159         tcf_exts_change(tp, &f->exts, &e);
 160         tcf_em_tree_change(tp, &f->ematches, &t);
 161
 162         return 0;
 163 errout:
 164         tcf_exts_destroy(tp, &e);
 165         return err;
 166 }
 167
 168 static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 169                         struct nlattr **tca, unsigned long *arg)
 170 {
 171         int err;
 172         struct basic_head *head = (struct basic_head *) tp->root;
 173         struct nlattr *tb[TCA_BASIC_MAX + 1];
 174         struct basic_filter *f = (struct basic_filter *) *arg;
 175
 176         if (tca[TCA_OPTIONS] == NULL)
 177                 return -EINVAL;
 178
 179         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 180                                basic_policy);
 181         if (err < 0)
 182                 return err;
 183
 184         if (f != NULL) {
 185                 if (handle && f->handle != handle)
 186                         return -EINVAL;
 187                 return basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 188         }
 189
 190         err = -ENOBUFS;
 191         f = kzalloc(sizeof(*f), GFP_KERNEL);
 192         if (f == NULL)
 193                 goto errout;
 194
 195         err = -EINVAL;
 196         if (handle)
 197                 f->handle = handle;
 198         else {
 199                 unsigned int i = 0x80000000;
 200                 do {
 201                         if (++head->hgenerator == 0x7FFFFFFF)
 202                                 head->hgenerator = 1;
 203                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 204
 205                 if (i <= 0) {
 206                         printk(KERN_ERR "Insufficient number of handles\n");
 207                         goto errout;
 208                 }
 209
 210                 f->handle = head->hgenerator;
 211         }
 212
 213         err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);
 214         if (err < 0)
 215                 goto errout;
 216
 217         tcf_tree_lock(tp);
 218         list_add(&f->link, &head->flist);
 219         tcf_tree_unlock(tp);
 220         *arg = (unsigned long) f;
 221
 222         return 0;
 223 errout:
 224         if (*arg == 0UL && f)
 225                 kfree(f);
 226
 227         return err;
 228 }
 229
 230 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 231 {
 232         struct basic_head *head = (struct basic_head *) tp->root;
 233         struct basic_filter *f;
 234
 235         list_for_each_entry(f, &head->flist, link) {
 236                 if (arg->count < arg->skip)
 237                         goto skip;
 238
 239                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 240                         arg->stop = 1;
 241                         break;
 242                 }
 243 skip:
 244                 arg->count++;
 245         }
 246 }
 247
 248 static int basic_dump(struct tcf_proto *tp, unsigned long fh,
 249                       struct sk_buff *skb, struct tcmsg *t)
 250 {
 251         struct basic_filter *f = (struct basic_filter *) fh;
 252         struct nlattr *nest;
 253
 254         if (f == NULL)
 255                 return skb->len;
 256
 257         t->tcm_handle = f->handle;
 258
 259         nest = nla_nest_start(skb, TCA_OPTIONS);
 260         if (nest == NULL)
 261                 goto nla_put_failure;
 262
 263         if (f->res.classid)
 264                 NLA_PUT_U32(skb, TCA_BASIC_CLASSID, f->res.classid);
 265
 266         if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
 267             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 268                 goto nla_put_failure;
 269
 270         nla_nest_end(skb, nest);
 271         return skb->len;
 272
 273 nla_put_failure:
 274         nla_nest_cancel(skb, nest);
 275         return -1;
 276 }
 277
 278 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 279         .kind           =       "basic",
 280         .classify       =       basic_classify,
 281         .init           =       basic_init,
 282         .destroy        =       basic_destroy,
 283         .get            =       basic_get,
 284         .put            =       basic_put,
 285         .change         =       basic_change,
 286         .delete         =       basic_delete,
 287         .walk           =       basic_walk,
 288         .dump           =       basic_dump,
 289         .owner          =       THIS_MODULE,
 290 };
 291
 292 static int __init init_basic(void)
 293 {
 294         return register_tcf_proto_ops(&cls_basic_ops);
 295 }
 296
 297 static void __exit exit_basic(void)
 298 {
 299         unregister_tcf_proto_ops(&cls_basic_ops);
 300 }
 301
 302 module_init(init_basic)
 303 module_exit(exit_basic)
 304 MODULE_LICENSE("GPL");
 305