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 <linux/idr.h>
  21 #include <net/netlink.h>
  22 #include <net/act_api.h>
  23 #include <net/pkt_cls.h>
  24
  25 struct basic_head {
  26         struct list_head        flist;
  27         struct idr              handle_idr;
  28         struct rcu_head         rcu;
  29 };
  30
  31 struct basic_filter {
  32         u32                     handle;
  33         struct tcf_exts         exts;
  34         struct tcf_ematch_tree  ematches;
  35         struct tcf_result       res;
  36         struct tcf_proto        *tp;
  37         struct list_head        link;
  38         union {
  39                 struct work_struct      work;
  40                 struct rcu_head         rcu;
  41         };
  42 };
  43
  44 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  45                           struct tcf_result *res)
  46 {
  47         int r;
  48         struct basic_head *head = rcu_dereference_bh(tp->root);
  49         struct basic_filter *f;
  50
  51         list_for_each_entry_rcu(f, &head->flist, link) {
  52                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  53                         continue;
  54                 *res = f->res;
  55                 r = tcf_exts_exec(skb, &f->exts, res);
  56                 if (r < 0)
  57                         continue;
  58                 return r;
  59         }
  60         return -1;
  61 }
  62
  63 static void *basic_get(struct tcf_proto *tp, u32 handle)
  64 {
  65         struct basic_head *head = rtnl_dereference(tp->root);
  66         struct basic_filter *f;
  67
  68         list_for_each_entry(f, &head->flist, link) {
  69                 if (f->handle == handle) {
  70                         return f;
  71                 }
  72         }
  73
  74         return NULL;
  75 }
  76
  77 static int basic_init(struct tcf_proto *tp)
  78 {
  79         struct basic_head *head;
  80
  81         head = kzalloc(sizeof(*head), GFP_KERNEL);
  82         if (head == NULL)
  83                 return -ENOBUFS;
  84         INIT_LIST_HEAD(&head->flist);
  85         idr_init(&head->handle_idr);
  86         rcu_assign_pointer(tp->root, head);
  87         return 0;
  88 }
  89
  90 static void __basic_delete_filter(struct basic_filter *f)
  91 {
  92         tcf_exts_destroy(&f->exts);
  93         tcf_em_tree_destroy(&f->ematches);
  94         tcf_exts_put_net(&f->exts);
  95         kfree(f);
  96 }
  97
  98 static void basic_delete_filter_work(struct work_struct *work)
  99 {
 100         struct basic_filter *f = container_of(work, struct basic_filter, work);
 101
 102         rtnl_lock();
 103         __basic_delete_filter(f);
 104         rtnl_unlock();
 105 }
 106
 107 static void basic_delete_filter(struct rcu_head *head)
 108 {
 109         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
 110
 111         INIT_WORK(&f->work, basic_delete_filter_work);
 112         tcf_queue_work(&f->work);
 113 }
 114
 115 static void basic_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 116 {
 117         struct basic_head *head = rtnl_dereference(tp->root);
 118         struct basic_filter *f, *n;
 119
 120         list_for_each_entry_safe(f, n, &head->flist, link) {
 121                 list_del_rcu(&f->link);
 122                 tcf_unbind_filter(tp, &f->res);
 123                 idr_remove(&head->handle_idr, f->handle);
 124                 if (tcf_exts_get_net(&f->exts))
 125                         call_rcu(&f->rcu, basic_delete_filter);
 126                 else
 127                         __basic_delete_filter(f);
 128         }
 129         idr_destroy(&head->handle_idr);
 130         kfree_rcu(head, rcu);
 131 }
 132
 133 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last,
 134                         struct netlink_ext_ack *extack)
 135 {
 136         struct basic_head *head = rtnl_dereference(tp->root);
 137         struct basic_filter *f = arg;
 138
 139         list_del_rcu(&f->link);
 140         tcf_unbind_filter(tp, &f->res);
 141         idr_remove(&head->handle_idr, f->handle);
 142         tcf_exts_get_net(&f->exts);
 143         call_rcu(&f->rcu, basic_delete_filter);
 144         *last = list_empty(&head->flist);
 145         return 0;
 146 }
 147
 148 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 149         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 150         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 151 };
 152
 153 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 154                            struct basic_filter *f, unsigned long base,
 155                            struct nlattr **tb,
 156                            struct nlattr *est, bool ovr,
 157                            struct netlink_ext_ack *extack)
 158 {
 159         int err;
 160
 161         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, extack);
 162         if (err < 0)
 163                 return err;
 164
 165         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 166         if (err < 0)
 167                 return err;
 168
 169         if (tb[TCA_BASIC_CLASSID]) {
 170                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 171                 tcf_bind_filter(tp, &f->res, base);
 172         }
 173
 174         f->tp = tp;
 175         return 0;
 176 }
 177
 178 static int basic_change(struct net *net, struct sk_buff *in_skb,
 179                         struct tcf_proto *tp, unsigned long base, u32 handle,
 180                         struct nlattr **tca, void **arg, bool ovr,
 181                         struct netlink_ext_ack *extack)
 182 {
 183         int err;
 184         struct basic_head *head = rtnl_dereference(tp->root);
 185         struct nlattr *tb[TCA_BASIC_MAX + 1];
 186         struct basic_filter *fold = (struct basic_filter *) *arg;
 187         struct basic_filter *fnew;
 188
 189         if (tca[TCA_OPTIONS] == NULL)
 190                 return -EINVAL;
 191
 192         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 193                                basic_policy, NULL);
 194         if (err < 0)
 195                 return err;
 196
 197         if (fold != NULL) {
 198                 if (handle && fold->handle != handle)
 199                         return -EINVAL;
 200         }
 201
 202         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 203         if (!fnew)
 204                 return -ENOBUFS;
 205
 206         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 207         if (err < 0)
 208                 goto errout;
 209
 210         if (!handle) {
 211                 handle = 1;
 212                 err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
 213                                     INT_MAX, GFP_KERNEL);
 214         } else if (!fold) {
 215                 err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
 216                                     handle, GFP_KERNEL);
 217         }
 218         if (err)
 219                 goto errout;
 220         fnew->handle = handle;
 221
 222         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr,
 223                               extack);
 224         if (err < 0) {
 225                 if (!fold)
 226                         idr_remove(&head->handle_idr, fnew->handle);
 227                 goto errout;
 228         }
 229
 230         *arg = fnew;
 231
 232         if (fold) {
 233                 idr_replace(&head->handle_idr, fnew, fnew->handle);
 234                 list_replace_rcu(&fold->link, &fnew->link);
 235                 tcf_unbind_filter(tp, &fold->res);
 236                 tcf_exts_get_net(&fold->exts);
 237                 call_rcu(&fold->rcu, basic_delete_filter);
 238         } else {
 239                 list_add_rcu(&fnew->link, &head->flist);
 240         }
 241
 242         return 0;
 243 errout:
 244         tcf_exts_destroy(&fnew->exts);
 245         kfree(fnew);
 246         return err;
 247 }
 248
 249 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 250 {
 251         struct basic_head *head = rtnl_dereference(tp->root);
 252         struct basic_filter *f;
 253
 254         list_for_each_entry(f, &head->flist, link) {
 255                 if (arg->count < arg->skip)
 256                         goto skip;
 257
 258                 if (arg->fn(tp, f, arg) < 0) {
 259                         arg->stop = 1;
 260                         break;
 261                 }
 262 skip:
 263                 arg->count++;
 264         }
 265 }
 266
 267 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 268 {
 269         struct basic_filter *f = fh;
 270
 271         if (f && f->res.classid == classid)
 272                 f->res.class = cl;
 273 }
 274
 275 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 276                       struct sk_buff *skb, struct tcmsg *t)
 277 {
 278         struct basic_filter *f = fh;
 279         struct nlattr *nest;
 280
 281         if (f == NULL)
 282                 return skb->len;
 283
 284         t->tcm_handle = f->handle;
 285
 286         nest = nla_nest_start(skb, TCA_OPTIONS);
 287         if (nest == NULL)
 288                 goto nla_put_failure;
 289
 290         if (f->res.classid &&
 291             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 292                 goto nla_put_failure;
 293
 294         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 295             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 296                 goto nla_put_failure;
 297
 298         nla_nest_end(skb, nest);
 299
 300         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 301                 goto nla_put_failure;
 302
 303         return skb->len;
 304
 305 nla_put_failure:
 306         nla_nest_cancel(skb, nest);
 307         return -1;
 308 }
 309
 310 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 311         .kind           =       "basic",
 312         .classify       =       basic_classify,
 313         .init           =       basic_init,
 314         .destroy        =       basic_destroy,
 315         .get            =       basic_get,
 316         .change         =       basic_change,
 317         .delete         =       basic_delete,
 318         .walk           =       basic_walk,
 319         .dump           =       basic_dump,
 320         .bind_class     =       basic_bind_class,
 321         .owner          =       THIS_MODULE,
 322 };
 323
 324 static int __init init_basic(void)
 325 {
 326         return register_tcf_proto_ops(&cls_basic_ops);
 327 }
 328
 329 static void __exit exit_basic(void)
 330 {
 331         unregister_tcf_proto_ops(&cls_basic_ops);
 332 }
 333
 334 module_init(init_basic)
 335 module_exit(exit_basic)
 336 MODULE_LICENSE("GPL");
 337