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         struct rcu_head         rcu;
  39 };
  40
  41 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  42                           struct tcf_result *res)
  43 {
  44         int r;
  45         struct basic_head *head = rcu_dereference_bh(tp->root);
  46         struct basic_filter *f;
  47
  48         list_for_each_entry_rcu(f, &head->flist, link) {
  49                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  50                         continue;
  51                 *res = f->res;
  52                 r = tcf_exts_exec(skb, &f->exts, res);
  53                 if (r < 0)
  54                         continue;
  55                 return r;
  56         }
  57         return -1;
  58 }
  59
  60 static void *basic_get(struct tcf_proto *tp, u32 handle)
  61 {
  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                         return f;
  68                 }
  69         }
  70
  71         return NULL;
  72 }
  73
  74 static int basic_init(struct tcf_proto *tp)
  75 {
  76         struct basic_head *head;
  77
  78         head = kzalloc(sizeof(*head), GFP_KERNEL);
  79         if (head == NULL)
  80                 return -ENOBUFS;
  81         INIT_LIST_HEAD(&head->flist);
  82         idr_init(&head->handle_idr);
  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 void basic_destroy(struct tcf_proto *tp)
  97 {
  98         struct basic_head *head = rtnl_dereference(tp->root);
  99         struct basic_filter *f, *n;
 100
 101         list_for_each_entry_safe(f, n, &head->flist, link) {
 102                 list_del_rcu(&f->link);
 103                 tcf_unbind_filter(tp, &f->res);
 104                 idr_remove_ext(&head->handle_idr, f->handle);
 105                 call_rcu(&f->rcu, basic_delete_filter);
 106         }
 107         idr_destroy(&head->handle_idr);
 108         kfree_rcu(head, rcu);
 109 }
 110
 111 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last)
 112 {
 113         struct basic_head *head = rtnl_dereference(tp->root);
 114         struct basic_filter *f = arg;
 115
 116         list_del_rcu(&f->link);
 117         tcf_unbind_filter(tp, &f->res);
 118         idr_remove_ext(&head->handle_idr, f->handle);
 119         call_rcu(&f->rcu, basic_delete_filter);
 120         *last = list_empty(&head->flist);
 121         return 0;
 122 }
 123
 124 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 125         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 126         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 127 };
 128
 129 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 130                            struct basic_filter *f, unsigned long base,
 131                            struct nlattr **tb,
 132                            struct nlattr *est, bool ovr)
 133 {
 134         int err;
 135
 136         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 137         if (err < 0)
 138                 return err;
 139
 140         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 141         if (err < 0)
 142                 return err;
 143
 144         if (tb[TCA_BASIC_CLASSID]) {
 145                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 146                 tcf_bind_filter(tp, &f->res, base);
 147         }
 148
 149         f->tp = tp;
 150         return 0;
 151 }
 152
 153 static int basic_change(struct net *net, struct sk_buff *in_skb,
 154                         struct tcf_proto *tp, unsigned long base, u32 handle,
 155                         struct nlattr **tca, void **arg, bool ovr)
 156 {
 157         int err;
 158         struct basic_head *head = rtnl_dereference(tp->root);
 159         struct nlattr *tb[TCA_BASIC_MAX + 1];
 160         struct basic_filter *fold = (struct basic_filter *) *arg;
 161         struct basic_filter *fnew;
 162         unsigned long idr_index;
 163
 164         if (tca[TCA_OPTIONS] == NULL)
 165                 return -EINVAL;
 166
 167         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 168                                basic_policy, NULL);
 169         if (err < 0)
 170                 return err;
 171
 172         if (fold != NULL) {
 173                 if (handle && fold->handle != handle)
 174                         return -EINVAL;
 175         }
 176
 177         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 178         if (!fnew)
 179                 return -ENOBUFS;
 180
 181         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 182         if (err < 0)
 183                 goto errout;
 184
 185         if (handle) {
 186                 fnew->handle = handle;
 187                 if (!fold) {
 188                         err = idr_alloc_ext(&head->handle_idr, fnew, &idr_index,
 189                                             handle, handle + 1, GFP_KERNEL);
 190                         if (err)
 191                                 goto errout;
 192                 }
 193         } else {
 194                 err = idr_alloc_ext(&head->handle_idr, fnew, &idr_index,
 195                                     1, 0x7FFFFFFF, GFP_KERNEL);
 196                 if (err)
 197                         goto errout;
 198                 fnew->handle = idr_index;
 199         }
 200
 201         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 202         if (err < 0) {
 203                 if (!fold)
 204                         idr_remove_ext(&head->handle_idr, fnew->handle);
 205                 goto errout;
 206         }
 207
 208         *arg = fnew;
 209
 210         if (fold) {
 211                 idr_replace_ext(&head->handle_idr, fnew, fnew->handle);
 212                 list_replace_rcu(&fold->link, &fnew->link);
 213                 tcf_unbind_filter(tp, &fold->res);
 214                 call_rcu(&fold->rcu, basic_delete_filter);
 215         } else {
 216                 list_add_rcu(&fnew->link, &head->flist);
 217         }
 218
 219         return 0;
 220 errout:
 221         tcf_exts_destroy(&fnew->exts);
 222         kfree(fnew);
 223         return err;
 224 }
 225
 226 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 227 {
 228         struct basic_head *head = rtnl_dereference(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, f, arg) < 0) {
 236                         arg->stop = 1;
 237                         break;
 238                 }
 239 skip:
 240                 arg->count++;
 241         }
 242 }
 243
 244 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 245 {
 246         struct basic_filter *f = fh;
 247
 248         if (f && f->res.classid == classid)
 249                 f->res.class = cl;
 250 }
 251
 252 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 253                       struct sk_buff *skb, struct tcmsg *t)
 254 {
 255         struct basic_filter *f = fh;
 256         struct nlattr *nest;
 257
 258         if (f == NULL)
 259                 return skb->len;
 260
 261         t->tcm_handle = f->handle;
 262
 263         nest = nla_nest_start(skb, TCA_OPTIONS);
 264         if (nest == NULL)
 265                 goto nla_put_failure;
 266
 267         if (f->res.classid &&
 268             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 269                 goto nla_put_failure;
 270
 271         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 272             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 273                 goto nla_put_failure;
 274
 275         nla_nest_end(skb, nest);
 276
 277         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 278                 goto nla_put_failure;
 279
 280         return skb->len;
 281
 282 nla_put_failure:
 283         nla_nest_cancel(skb, nest);
 284         return -1;
 285 }
 286
 287 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 288         .kind           =       "basic",
 289         .classify       =       basic_classify,
 290         .init           =       basic_init,
 291         .destroy        =       basic_destroy,
 292         .get            =       basic_get,
 293         .change         =       basic_change,
 294         .delete         =       basic_delete,
 295         .walk           =       basic_walk,
 296         .dump           =       basic_dump,
 297         .bind_class     =       basic_bind_class,
 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