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         struct rcu_head         rcu;
  28 };
  29
  30 struct basic_filter {
  31         u32                     handle;
  32         struct tcf_exts         exts;
  33         struct tcf_ematch_tree  ematches;
  34         struct tcf_result       res;
  35         struct tcf_proto        *tp;
  36         struct list_head        link;
  37         struct rcu_head         rcu;
  38 };
  39
  40 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  41                           struct tcf_result *res)
  42 {
  43         int r;
  44         struct basic_head *head = rcu_dereference_bh(tp->root);
  45         struct basic_filter *f;
  46
  47         list_for_each_entry_rcu(f, &head->flist, link) {
  48                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  49                         continue;
  50                 *res = f->res;
  51                 r = tcf_exts_exec(skb, &f->exts, res);
  52                 if (r < 0)
  53                         continue;
  54                 return r;
  55         }
  56         return -1;
  57 }
  58
  59 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  60 {
  61         unsigned long l = 0UL;
  62         struct basic_head *head = rtnl_dereference(tp->root);
  63         struct basic_filter *f;
  64
  65         list_for_each_entry(f, &head->flist, link) {
  66                 if (f->handle == handle) {
  67                         l = (unsigned long) f;
  68                         break;
  69                 }
  70         }
  71
  72         return l;
  73 }
  74
  75 static int basic_init(struct tcf_proto *tp)
  76 {
  77         struct basic_head *head;
  78
  79         head = kzalloc(sizeof(*head), GFP_KERNEL);
  80         if (head == NULL)
  81                 return -ENOBUFS;
  82         INIT_LIST_HEAD(&head->flist);
  83         rcu_assign_pointer(tp->root, head);
  84         return 0;
  85 }
  86
  87 static void basic_delete_filter(struct rcu_head *head)
  88 {
  89         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
  90
  91         tcf_exts_destroy(&f->exts);
  92         tcf_em_tree_destroy(&f->ematches);
  93         kfree(f);
  94 }
  95
  96 static bool basic_destroy(struct tcf_proto *tp, bool force)
  97 {
  98         struct basic_head *head = rtnl_dereference(tp->root);
  99         struct basic_filter *f, *n;
 100
 101         if (!force && !list_empty(&head->flist))
 102                 return false;
 103
 104         list_for_each_entry_safe(f, n, &head->flist, link) {
 105                 list_del_rcu(&f->link);
 106                 tcf_unbind_filter(tp, &f->res);
 107                 call_rcu(&f->rcu, basic_delete_filter);
 108         }
 109         kfree_rcu(head, rcu);
 110         return true;
 111 }
 112
 113 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 114 {
 115         struct basic_filter *f = (struct basic_filter *) arg;
 116
 117         list_del_rcu(&f->link);
 118         tcf_unbind_filter(tp, &f->res);
 119         call_rcu(&f->rcu, basic_delete_filter);
 120         return 0;
 121 }
 122
 123 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 124         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 125         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 126 };
 127
 128 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 129                            struct basic_filter *f, unsigned long base,
 130                            struct nlattr **tb,
 131                            struct nlattr *est, bool ovr)
 132 {
 133         int err;
 134         struct tcf_exts e;
 135         struct tcf_ematch_tree t;
 136
 137         err = tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 138         if (err < 0)
 139                 return err;
 140         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 141         if (err < 0)
 142                 goto errout;
 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         f->tp = tp;
 156
 157         return 0;
 158 errout:
 159         tcf_exts_destroy(&e);
 160         return err;
 161 }
 162
 163 static int basic_change(struct net *net, struct sk_buff *in_skb,
 164                         struct tcf_proto *tp, unsigned long base, u32 handle,
 165                         struct nlattr **tca, unsigned long *arg, bool ovr)
 166 {
 167         int err;
 168         struct basic_head *head = rtnl_dereference(tp->root);
 169         struct nlattr *tb[TCA_BASIC_MAX + 1];
 170         struct basic_filter *fold = (struct basic_filter *) *arg;
 171         struct basic_filter *fnew;
 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 (fold != NULL) {
 182                 if (handle && fold->handle != handle)
 183                         return -EINVAL;
 184         }
 185
 186         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 187         if (!fnew)
 188                 return -ENOBUFS;
 189
 190         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 191         if (err < 0)
 192                 goto errout;
 193
 194         err = -EINVAL;
 195         if (handle) {
 196                 fnew->handle = handle;
 197         } else if (fold) {
 198                 fnew->handle = fold->handle;
 199         } else {
 200                 unsigned int i = 0x80000000;
 201                 do {
 202                         if (++head->hgenerator == 0x7FFFFFFF)
 203                                 head->hgenerator = 1;
 204                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 205
 206                 if (i <= 0) {
 207                         pr_err("Insufficient number of handles\n");
 208                         goto errout;
 209                 }
 210
 211                 fnew->handle = head->hgenerator;
 212         }
 213
 214         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 215         if (err < 0)
 216                 goto errout;
 217
 218         *arg = (unsigned long)fnew;
 219
 220         if (fold) {
 221                 list_replace_rcu(&fold->link, &fnew->link);
 222                 tcf_unbind_filter(tp, &fold->res);
 223                 call_rcu(&fold->rcu, basic_delete_filter);
 224         } else {
 225                 list_add_rcu(&fnew->link, &head->flist);
 226         }
 227
 228         return 0;
 229 errout:
 230         tcf_exts_destroy(&fnew->exts);
 231         kfree(fnew);
 232         return err;
 233 }
 234
 235 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 236 {
 237         struct basic_head *head = rtnl_dereference(tp->root);
 238         struct basic_filter *f;
 239
 240         list_for_each_entry(f, &head->flist, link) {
 241                 if (arg->count < arg->skip)
 242                         goto skip;
 243
 244                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 245                         arg->stop = 1;
 246                         break;
 247                 }
 248 skip:
 249                 arg->count++;
 250         }
 251 }
 252
 253 static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 254                       struct sk_buff *skb, struct tcmsg *t)
 255 {
 256         struct basic_filter *f = (struct basic_filter *) fh;
 257         struct nlattr *nest;
 258
 259         if (f == NULL)
 260                 return skb->len;
 261
 262         t->tcm_handle = f->handle;
 263
 264         nest = nla_nest_start(skb, TCA_OPTIONS);
 265         if (nest == NULL)
 266                 goto nla_put_failure;
 267
 268         if (f->res.classid &&
 269             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 270                 goto nla_put_failure;
 271
 272         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 273             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 274                 goto nla_put_failure;
 275
 276         nla_nest_end(skb, nest);
 277
 278         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 279                 goto nla_put_failure;
 280
 281         return skb->len;
 282
 283 nla_put_failure:
 284         nla_nest_cancel(skb, nest);
 285         return -1;
 286 }
 287
 288 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 289         .kind           =       "basic",
 290         .classify       =       basic_classify,
 291         .init           =       basic_init,
 292         .destroy        =       basic_destroy,
 293         .get            =       basic_get,
 294         .change         =       basic_change,
 295         .delete         =       basic_delete,
 296         .walk           =       basic_walk,
 297         .dump           =       basic_dump,
 298         .owner          =       THIS_MODULE,
 299 };
 300
 301 static int __init init_basic(void)
 302 {
 303         return register_tcf_proto_ops(&cls_basic_ops);
 304 }
 305
 306 static void __exit exit_basic(void)
 307 {
 308         unregister_tcf_proto_ops(&cls_basic_ops);
 309 }
 310
 311 module_init(init_basic)
 312 module_exit(exit_basic)
 313 MODULE_LICENSE("GPL");
 314