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         union {
  38                 struct work_struct      work;
  39                 struct rcu_head         rcu;
  40         };
  41 };
  42
  43 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  44                           struct tcf_result *res)
  45 {
  46         int r;
  47         struct basic_head *head = rcu_dereference_bh(tp->root);
  48         struct basic_filter *f;
  49
  50         list_for_each_entry_rcu(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 void *basic_get(struct tcf_proto *tp, u32 handle)
  63 {
  64         struct basic_head *head = rtnl_dereference(tp->root);
  65         struct basic_filter *f;
  66
  67         list_for_each_entry(f, &head->flist, link) {
  68                 if (f->handle == handle) {
  69                         return f;
  70                 }
  71         }
  72
  73         return NULL;
  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         rcu_assign_pointer(tp->root, head);
  85         return 0;
  86 }
  87
  88 static void basic_delete_filter_work(struct work_struct *work)
  89 {
  90         struct basic_filter *f = container_of(work, struct basic_filter, work);
  91
  92         rtnl_lock();
  93         tcf_exts_destroy(&f->exts);
  94         tcf_em_tree_destroy(&f->ematches);
  95         rtnl_unlock();
  96
  97         kfree(f);
  98 }
  99
 100 static void basic_delete_filter(struct rcu_head *head)
 101 {
 102         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
 103
 104         INIT_WORK(&f->work, basic_delete_filter_work);
 105         tcf_queue_work(&f->work);
 106 }
 107
 108 static void basic_destroy(struct tcf_proto *tp)
 109 {
 110         struct basic_head *head = rtnl_dereference(tp->root);
 111         struct basic_filter *f, *n;
 112
 113         list_for_each_entry_safe(f, n, &head->flist, link) {
 114                 list_del_rcu(&f->link);
 115                 tcf_unbind_filter(tp, &f->res);
 116                 call_rcu(&f->rcu, basic_delete_filter);
 117         }
 118         kfree_rcu(head, rcu);
 119 }
 120
 121 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last)
 122 {
 123         struct basic_head *head = rtnl_dereference(tp->root);
 124         struct basic_filter *f = arg;
 125
 126         list_del_rcu(&f->link);
 127         tcf_unbind_filter(tp, &f->res);
 128         call_rcu(&f->rcu, basic_delete_filter);
 129         *last = list_empty(&head->flist);
 130         return 0;
 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 int basic_set_parms(struct net *net, struct tcf_proto *tp,
 139                            struct basic_filter *f, unsigned long base,
 140                            struct nlattr **tb,
 141                            struct nlattr *est, bool ovr)
 142 {
 143         int err;
 144
 145         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 146         if (err < 0)
 147                 return err;
 148
 149         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 150         if (err < 0)
 151                 return err;
 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         f->tp = tp;
 159         return 0;
 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, void **arg, bool ovr)
 165 {
 166         int err;
 167         struct basic_head *head = rtnl_dereference(tp->root);
 168         struct nlattr *tb[TCA_BASIC_MAX + 1];
 169         struct basic_filter *fold = (struct basic_filter *) *arg;
 170         struct basic_filter *fnew;
 171
 172         if (tca[TCA_OPTIONS] == NULL)
 173                 return -EINVAL;
 174
 175         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 176                                basic_policy, NULL);
 177         if (err < 0)
 178                 return err;
 179
 180         if (fold != NULL) {
 181                 if (handle && fold->handle != handle)
 182                         return -EINVAL;
 183         }
 184
 185         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 186         if (!fnew)
 187                 return -ENOBUFS;
 188
 189         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 190         if (err < 0)
 191                 goto errout;
 192
 193         err = -EINVAL;
 194         if (handle) {
 195                 fnew->handle = handle;
 196         } else if (fold) {
 197                 fnew->handle = fold->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                         pr_err("Insufficient number of handles\n");
 207                         goto errout;
 208                 }
 209
 210                 fnew->handle = head->hgenerator;
 211         }
 212
 213         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 214         if (err < 0)
 215                 goto errout;
 216
 217         *arg = fnew;
 218
 219         if (fold) {
 220                 list_replace_rcu(&fold->link, &fnew->link);
 221                 tcf_unbind_filter(tp, &fold->res);
 222                 call_rcu(&fold->rcu, basic_delete_filter);
 223         } else {
 224                 list_add_rcu(&fnew->link, &head->flist);
 225         }
 226
 227         return 0;
 228 errout:
 229         tcf_exts_destroy(&fnew->exts);
 230         kfree(fnew);
 231         return err;
 232 }
 233
 234 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 235 {
 236         struct basic_head *head = rtnl_dereference(tp->root);
 237         struct basic_filter *f;
 238
 239         list_for_each_entry(f, &head->flist, link) {
 240                 if (arg->count < arg->skip)
 241                         goto skip;
 242
 243                 if (arg->fn(tp, f, arg) < 0) {
 244                         arg->stop = 1;
 245                         break;
 246                 }
 247 skip:
 248                 arg->count++;
 249         }
 250 }
 251
 252 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 253 {
 254         struct basic_filter *f = fh;
 255
 256         if (f && f->res.classid == classid)
 257                 f->res.class = cl;
 258 }
 259
 260 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 261                       struct sk_buff *skb, struct tcmsg *t)
 262 {
 263         struct basic_filter *f = fh;
 264         struct nlattr *nest;
 265
 266         if (f == NULL)
 267                 return skb->len;
 268
 269         t->tcm_handle = f->handle;
 270
 271         nest = nla_nest_start(skb, TCA_OPTIONS);
 272         if (nest == NULL)
 273                 goto nla_put_failure;
 274
 275         if (f->res.classid &&
 276             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 277                 goto nla_put_failure;
 278
 279         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 280             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 281                 goto nla_put_failure;
 282
 283         nla_nest_end(skb, nest);
 284
 285         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 286                 goto nla_put_failure;
 287
 288         return skb->len;
 289
 290 nla_put_failure:
 291         nla_nest_cancel(skb, nest);
 292         return -1;
 293 }
 294
 295 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 296         .kind           =       "basic",
 297         .classify       =       basic_classify,
 298         .init           =       basic_init,
 299         .destroy        =       basic_destroy,
 300         .get            =       basic_get,
 301         .change         =       basic_change,
 302         .delete         =       basic_delete,
 303         .walk           =       basic_walk,
 304         .dump           =       basic_dump,
 305         .bind_class     =       basic_bind_class,
 306         .owner          =       THIS_MODULE,
 307 };
 308
 309 static int __init init_basic(void)
 310 {
 311         return register_tcf_proto_ops(&cls_basic_ops);
 312 }
 313
 314 static void __exit exit_basic(void)
 315 {
 316         unregister_tcf_proto_ops(&cls_basic_ops);
 317 }
 318
 319 module_init(init_basic)
 320 module_exit(exit_basic)
 321 MODULE_LICENSE("GPL");
 322