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 int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  38                           struct tcf_result *res)
  39 {
  40         int r;
  41         struct basic_head *head = tp->root;
  42         struct basic_filter *f;
  43
  44         list_for_each_entry(f, &head->flist, link) {
  45                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  46                         continue;
  47                 *res = f->res;
  48                 r = tcf_exts_exec(skb, &f->exts, res);
  49                 if (r < 0)
  50                         continue;
  51                 return r;
  52         }
  53         return -1;
  54 }
  55
  56 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  57 {
  58         unsigned long l = 0UL;
  59         struct basic_head *head = tp->root;
  60         struct basic_filter *f;
  61
  62         if (head == NULL)
  63                 return 0UL;
  64
  65         list_for_each_entry(f, &head->flist, link)
  66                 if (f->handle == handle)
  67                         l = (unsigned long) f;
  68
  69         return l;
  70 }
  71
  72 static void basic_put(struct tcf_proto *tp, unsigned long f)
  73 {
  74 }
  75
  76 static int basic_init(struct tcf_proto *tp)
  77 {
  78         struct basic_head *head;
  79
  80         head = kzalloc(sizeof(*head), GFP_KERNEL);
  81         if (head == NULL)
  82                 return -ENOBUFS;
  83         INIT_LIST_HEAD(&head->flist);
  84         tp->root = head;
  85         return 0;
  86 }
  87
  88 static void basic_delete_filter(struct tcf_proto *tp, struct basic_filter *f)
  89 {
  90         tcf_unbind_filter(tp, &f->res);
  91         tcf_exts_destroy(tp, &f->exts);
  92         tcf_em_tree_destroy(tp, &f->ematches);
  93         kfree(f);
  94 }
  95
  96 static void basic_destroy(struct tcf_proto *tp)
  97 {
  98         struct basic_head *head = tp->root;
  99         struct basic_filter *f, *n;
 100
 101         list_for_each_entry_safe(f, n, &head->flist, link) {
 102                 list_del(&f->link);
 103                 basic_delete_filter(tp, f);
 104         }
 105         kfree(head);
 106 }
 107
 108 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 109 {
 110         struct basic_head *head = tp->root;
 111         struct basic_filter *t, *f = (struct basic_filter *) arg;
 112
 113         list_for_each_entry(t, &head->flist, link)
 114                 if (t == f) {
 115                         tcf_tree_lock(tp);
 116                         list_del(&t->link);
 117                         tcf_tree_unlock(tp);
 118                         basic_delete_filter(tp, t);
 119                         return 0;
 120                 }
 121
 122         return -ENOENT;
 123 }
 124
 125 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 126         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 127         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 128 };
 129
 130 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 131                            struct basic_filter *f, unsigned long base,
 132                            struct nlattr **tb,
 133                            struct nlattr *est, bool ovr)
 134 {
 135         int err;
 136         struct tcf_exts e;
 137         struct tcf_ematch_tree t;
 138
 139         tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 140         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 141         if (err < 0)
 142                 return err;
 143
 144         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 145         if (err < 0)
 146                 goto errout;
 147
 148         if (tb[TCA_BASIC_CLASSID]) {
 149                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 150                 tcf_bind_filter(tp, &f->res, base);
 151         }
 152
 153         tcf_exts_change(tp, &f->exts, &e);
 154         tcf_em_tree_change(tp, &f->ematches, &t);
 155
 156         return 0;
 157 errout:
 158         tcf_exts_destroy(tp, &e);
 159         return err;
 160 }
 161
 162 static int basic_change(struct net *net, struct sk_buff *in_skb,
 163                         struct tcf_proto *tp, unsigned long base, u32 handle,
 164                         struct nlattr **tca, unsigned long *arg, bool ovr)
 165 {
 166         int err;
 167         struct basic_head *head = tp->root;
 168         struct nlattr *tb[TCA_BASIC_MAX + 1];
 169         struct basic_filter *f = (struct basic_filter *) *arg;
 170
 171         if (tca[TCA_OPTIONS] == NULL)
 172                 return -EINVAL;
 173
 174         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 175                                basic_policy);
 176         if (err < 0)
 177                 return err;
 178
 179         if (f != NULL) {
 180                 if (handle && f->handle != handle)
 181                         return -EINVAL;
 182                 return basic_set_parms(net, tp, f, base, tb, tca[TCA_RATE], ovr);
 183         }
 184
 185         err = -ENOBUFS;
 186         f = kzalloc(sizeof(*f), GFP_KERNEL);
 187         if (f == NULL)
 188                 goto errout;
 189
 190         tcf_exts_init(&f->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 191         err = -EINVAL;
 192         if (handle)
 193                 f->handle = handle;
 194         else {
 195                 unsigned int i = 0x80000000;
 196                 do {
 197                         if (++head->hgenerator == 0x7FFFFFFF)
 198                                 head->hgenerator = 1;
 199                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 200
 201                 if (i <= 0) {
 202                         pr_err("Insufficient number of handles\n");
 203                         goto errout;
 204                 }
 205
 206                 f->handle = head->hgenerator;
 207         }
 208
 209         err = basic_set_parms(net, tp, f, base, tb, tca[TCA_RATE], ovr);
 210         if (err < 0)
 211                 goto errout;
 212
 213         tcf_tree_lock(tp);
 214         list_add(&f->link, &head->flist);
 215         tcf_tree_unlock(tp);
 216         *arg = (unsigned long) f;
 217
 218         return 0;
 219 errout:
 220         if (*arg == 0UL && f)
 221                 kfree(f);
 222
 223         return err;
 224 }
 225
 226 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 227 {
 228         struct basic_head *head = tp->root;
 229         struct basic_filter *f;
 230
 231         list_for_each_entry(f, &head->flist, link) {
 232                 if (arg->count < arg->skip)
 233                         goto skip;
 234
 235                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 236                         arg->stop = 1;
 237                         break;
 238                 }
 239 skip:
 240                 arg->count++;
 241         }
 242 }
 243
 244 static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 245                       struct sk_buff *skb, struct tcmsg *t)
 246 {
 247         struct basic_filter *f = (struct basic_filter *) fh;
 248         struct nlattr *nest;
 249
 250         if (f == NULL)
 251                 return skb->len;
 252
 253         t->tcm_handle = f->handle;
 254
 255         nest = nla_nest_start(skb, TCA_OPTIONS);
 256         if (nest == NULL)
 257                 goto nla_put_failure;
 258
 259         if (f->res.classid &&
 260             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 261                 goto nla_put_failure;
 262
 263         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 264             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 265                 goto nla_put_failure;
 266
 267         nla_nest_end(skb, nest);
 268
 269         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 270                 goto nla_put_failure;
 271
 272         return skb->len;
 273
 274 nla_put_failure:
 275         nla_nest_cancel(skb, nest);
 276         return -1;
 277 }
 278
 279 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 280         .kind           =       "basic",
 281         .classify       =       basic_classify,
 282         .init           =       basic_init,
 283         .destroy        =       basic_destroy,
 284         .get            =       basic_get,
 285         .put            =       basic_put,
 286         .change         =       basic_change,
 287         .delete         =       basic_delete,
 288         .walk           =       basic_walk,
 289         .dump           =       basic_dump,
 290         .owner          =       THIS_MODULE,
 291 };
 292
 293 static int __init init_basic(void)
 294 {
 295         return register_tcf_proto_ops(&cls_basic_ops);
 296 }
 297
 298 static void __exit exit_basic(void)
 299 {
 300         unregister_tcf_proto_ops(&cls_basic_ops);
 301 }
 302
 303 module_init(init_basic)
 304 module_exit(exit_basic)
 305 MODULE_LICENSE("GPL");
 306