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         if (head == NULL)
  66                 return 0UL;
  67
  68         list_for_each_entry(f, &head->flist, link)
  69                 if (f->handle == handle)
  70                         l = (unsigned long) f;
  71
  72         return l;
  73 }
  74
  75 static void basic_put(struct tcf_proto *tp, unsigned long f)
  76 {
  77 }
  78
  79 static int basic_init(struct tcf_proto *tp)
  80 {
  81         struct basic_head *head;
  82
  83         head = kzalloc(sizeof(*head), GFP_KERNEL);
  84         if (head == NULL)
  85                 return -ENOBUFS;
  86         INIT_LIST_HEAD(&head->flist);
  87         rcu_assign_pointer(tp->root, head);
  88         return 0;
  89 }
  90
  91 static void basic_delete_filter(struct rcu_head *head)
  92 {
  93         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
  94         struct tcf_proto *tp = f->tp;
  95
  96         tcf_unbind_filter(tp, &f->res);
  97         tcf_exts_destroy(&f->exts);
  98         tcf_em_tree_destroy(tp, &f->ematches);
  99         kfree(f);
 100 }
 101
 102 static void basic_destroy(struct tcf_proto *tp)
 103 {
 104         struct basic_head *head = rtnl_dereference(tp->root);
 105         struct basic_filter *f, *n;
 106
 107         list_for_each_entry_safe(f, n, &head->flist, link) {
 108                 list_del_rcu(&f->link);
 109                 call_rcu(&f->rcu, basic_delete_filter);
 110         }
 111         RCU_INIT_POINTER(tp->root, NULL);
 112         kfree_rcu(head, rcu);
 113 }
 114
 115 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 116 {
 117         struct basic_head *head = rtnl_dereference(tp->root);
 118         struct basic_filter *t, *f = (struct basic_filter *) arg;
 119
 120         list_for_each_entry(t, &head->flist, link)
 121                 if (t == f) {
 122                         list_del_rcu(&t->link);
 123                         call_rcu(&t->rcu, basic_delete_filter);
 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, bool ovr)
 139 {
 140         int err;
 141         struct tcf_exts e;
 142         struct tcf_ematch_tree t;
 143
 144         tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 145         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 146         if (err < 0)
 147                 return err;
 148
 149         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 150         if (err < 0)
 151                 goto errout;
 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         tcf_exts_change(tp, &f->exts, &e);
 159         tcf_em_tree_change(tp, &f->ematches, &t);
 160         f->tp = tp;
 161
 162         return 0;
 163 errout:
 164         tcf_exts_destroy(&e);
 165         return err;
 166 }
 167
 168 static int basic_change(struct net *net, struct sk_buff *in_skb,
 169                         struct tcf_proto *tp, unsigned long base, u32 handle,
 170                         struct nlattr **tca, unsigned long *arg, bool ovr)
 171 {
 172         int err;
 173         struct basic_head *head = rtnl_dereference(tp->root);
 174         struct nlattr *tb[TCA_BASIC_MAX + 1];
 175         struct basic_filter *fold = (struct basic_filter *) *arg;
 176         struct basic_filter *fnew;
 177
 178         if (tca[TCA_OPTIONS] == NULL)
 179                 return -EINVAL;
 180
 181         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 182                                basic_policy);
 183         if (err < 0)
 184                 return err;
 185
 186         if (fold != NULL) {
 187                 if (handle && fold->handle != handle)
 188                         return -EINVAL;
 189         }
 190
 191         err = -ENOBUFS;
 192         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 193         if (fnew == NULL)
 194                 goto errout;
 195
 196         tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 197         err = -EINVAL;
 198         if (handle) {
 199                 fnew->handle = handle;
 200         } else if (fold) {
 201                 fnew->handle = fold->handle;
 202         } else {
 203                 unsigned int i = 0x80000000;
 204                 do {
 205                         if (++head->hgenerator == 0x7FFFFFFF)
 206                                 head->hgenerator = 1;
 207                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 208
 209                 if (i <= 0) {
 210                         pr_err("Insufficient number of handles\n");
 211                         goto errout;
 212                 }
 213
 214                 fnew->handle = head->hgenerator;
 215         }
 216
 217         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 218         if (err < 0)
 219                 goto errout;
 220
 221         *arg = (unsigned long)fnew;
 222
 223         if (fold) {
 224                 list_replace_rcu(&fold->link, &fnew->link);
 225                 call_rcu(&fold->rcu, basic_delete_filter);
 226         } else {
 227                 list_add_rcu(&fnew->link, &head->flist);
 228         }
 229
 230         return 0;
 231 errout:
 232         kfree(fnew);
 233         return err;
 234 }
 235
 236 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 237 {
 238         struct basic_head *head = rtnl_dereference(tp->root);
 239         struct basic_filter *f;
 240
 241         list_for_each_entry(f, &head->flist, link) {
 242                 if (arg->count < arg->skip)
 243                         goto skip;
 244
 245                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 246                         arg->stop = 1;
 247                         break;
 248                 }
 249 skip:
 250                 arg->count++;
 251         }
 252 }
 253
 254 static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 255                       struct sk_buff *skb, struct tcmsg *t)
 256 {
 257         struct basic_filter *f = (struct basic_filter *) fh;
 258         struct nlattr *nest;
 259
 260         if (f == NULL)
 261                 return skb->len;
 262
 263         t->tcm_handle = f->handle;
 264
 265         nest = nla_nest_start(skb, TCA_OPTIONS);
 266         if (nest == NULL)
 267                 goto nla_put_failure;
 268
 269         if (f->res.classid &&
 270             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 271                 goto nla_put_failure;
 272
 273         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 274             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 275                 goto nla_put_failure;
 276
 277         nla_nest_end(skb, nest);
 278
 279         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 280                 goto nla_put_failure;
 281
 282         return skb->len;
 283
 284 nla_put_failure:
 285         nla_nest_cancel(skb, nest);
 286         return -1;
 287 }
 288
 289 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 290         .kind           =       "basic",
 291         .classify       =       basic_classify,
 292         .init           =       basic_init,
 293         .destroy        =       basic_destroy,
 294         .get            =       basic_get,
 295         .put            =       basic_put,
 296         .change         =       basic_change,
 297         .delete         =       basic_delete,
 298         .walk           =       basic_walk,
 299         .dump           =       basic_dump,
 300         .owner          =       THIS_MODULE,
 301 };
 302
 303 static int __init init_basic(void)
 304 {
 305         return register_tcf_proto_ops(&cls_basic_ops);
 306 }
 307
 308 static void __exit exit_basic(void)
 309 {
 310         unregister_tcf_proto_ops(&cls_basic_ops);
 311 }
 312
 313 module_init(init_basic)
 314 module_exit(exit_basic)
 315 MODULE_LICENSE("GPL");
 316