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 net *net, struct tcf_proto *tp,
 136                            struct basic_filter *f, unsigned long base,
 137                            struct nlattr **tb,
 138                            struct nlattr *est)
 139 {
 140         int err;
 141         struct tcf_exts e;
 142         struct tcf_ematch_tree t;
 143
 144         err = tcf_exts_validate(net, tp, tb, est, &e, &basic_ext_map);
 145         if (err < 0)
 146                 return err;
 147
 148         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 149         if (err < 0)
 150                 goto errout;
 151
 152         if (tb[TCA_BASIC_CLASSID]) {
 153                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 154                 tcf_bind_filter(tp, &f->res, base);
 155         }
 156
 157         tcf_exts_change(tp, &f->exts, &e);
 158         tcf_em_tree_change(tp, &f->ematches, &t);
 159
 160         return 0;
 161 errout:
 162         tcf_exts_destroy(tp, &e);
 163         return err;
 164 }
 165
 166 static int basic_change(struct net *net, struct sk_buff *in_skb,
 167                         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(net, 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                         pr_err("Insufficient number of handles\n");
 206                         goto errout;
 207                 }
 208
 209                 f->handle = head->hgenerator;
 210         }
 211
 212         err = basic_set_parms(net, 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                 goto nla_put_failure;
 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
 272         if (tcf_exts_dump_stats(skb, &f->exts, &basic_ext_map) < 0)
 273                 goto nla_put_failure;
 274
 275         return skb->len;
 276
 277 nla_put_failure:
 278         nla_nest_cancel(skb, nest);
 279         return -1;
 280 }
 281
 282 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 283         .kind           =       "basic",
 284         .classify       =       basic_classify,
 285         .init           =       basic_init,
 286         .destroy        =       basic_destroy,
 287         .get            =       basic_get,
 288         .put            =       basic_put,
 289         .change         =       basic_change,
 290         .delete         =       basic_delete,
 291         .walk           =       basic_walk,
 292         .dump           =       basic_dump,
 293         .owner          =       THIS_MODULE,
 294 };
 295
 296 static int __init init_basic(void)
 297 {
 298         return register_tcf_proto_ops(&cls_basic_ops);
 299 }
 300
 301 static void __exit exit_basic(void)
 302 {
 303         unregister_tcf_proto_ops(&cls_basic_ops);
 304 }
 305
 306 module_init(init_basic)
 307 module_exit(exit_basic)
 308 MODULE_LICENSE("GPL");
 309