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 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 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                 call_rcu(&f->rcu, basic_delete_filter);
 105         }
 106         RCU_INIT_POINTER(tp->root, NULL);
 107         kfree_rcu(head, rcu);
 108 }
 109
 110 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 111 {
 112         struct basic_filter *f = (struct basic_filter *) arg;
 113
 114         list_del_rcu(&f->link);
 115         tcf_unbind_filter(tp, &f->res);
 116         call_rcu(&f->rcu, basic_delete_filter);
 117         return 0;
 118 }
 119
 120 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 121         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 122         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 123 };
 124
 125 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 126                            struct basic_filter *f, unsigned long base,
 127                            struct nlattr **tb,
 128                            struct nlattr *est, bool ovr)
 129 {
 130         int err;
 131         struct tcf_exts e;
 132         struct tcf_ematch_tree t;
 133
 134         tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 135         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 136         if (err < 0)
 137                 return err;
 138
 139         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
 140         if (err < 0)
 141                 goto errout;
 142
 143         if (tb[TCA_BASIC_CLASSID]) {
 144                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 145                 tcf_bind_filter(tp, &f->res, base);
 146         }
 147
 148         tcf_exts_change(tp, &f->exts, &e);
 149         tcf_em_tree_change(tp, &f->ematches, &t);
 150         f->tp = tp;
 151
 152         return 0;
 153 errout:
 154         tcf_exts_destroy(&e);
 155         return err;
 156 }
 157
 158 static int basic_change(struct net *net, struct sk_buff *in_skb,
 159                         struct tcf_proto *tp, unsigned long base, u32 handle,
 160                         struct nlattr **tca, unsigned long *arg, bool ovr)
 161 {
 162         int err;
 163         struct basic_head *head = rtnl_dereference(tp->root);
 164         struct nlattr *tb[TCA_BASIC_MAX + 1];
 165         struct basic_filter *fold = (struct basic_filter *) *arg;
 166         struct basic_filter *fnew;
 167
 168         if (tca[TCA_OPTIONS] == NULL)
 169                 return -EINVAL;
 170
 171         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 172                                basic_policy);
 173         if (err < 0)
 174                 return err;
 175
 176         if (fold != NULL) {
 177                 if (handle && fold->handle != handle)
 178                         return -EINVAL;
 179         }
 180
 181         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 182         if (!fnew)
 183                 return -ENOBUFS;
 184
 185         tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 186         err = -EINVAL;
 187         if (handle) {
 188                 fnew->handle = handle;
 189         } else if (fold) {
 190                 fnew->handle = fold->handle;
 191         } else {
 192                 unsigned int i = 0x80000000;
 193                 do {
 194                         if (++head->hgenerator == 0x7FFFFFFF)
 195                                 head->hgenerator = 1;
 196                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 197
 198                 if (i <= 0) {
 199                         pr_err("Insufficient number of handles\n");
 200                         goto errout;
 201                 }
 202
 203                 fnew->handle = head->hgenerator;
 204         }
 205
 206         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 207         if (err < 0)
 208                 goto errout;
 209
 210         *arg = (unsigned long)fnew;
 211
 212         if (fold) {
 213                 list_replace_rcu(&fold->link, &fnew->link);
 214                 tcf_unbind_filter(tp, &fold->res);
 215                 call_rcu(&fold->rcu, basic_delete_filter);
 216         } else {
 217                 list_add_rcu(&fnew->link, &head->flist);
 218         }
 219
 220         return 0;
 221 errout:
 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, (unsigned long) f, arg) < 0) {
 236                         arg->stop = 1;
 237                         break;
 238                 }
 239 skip:
 240                 arg->count++;
 241         }
 242 }
 243
 244 static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 245                       struct sk_buff *skb, struct tcmsg *t)
 246 {
 247         struct basic_filter *f = (struct basic_filter *) fh;
 248         struct nlattr *nest;
 249
 250         if (f == NULL)
 251                 return skb->len;
 252
 253         t->tcm_handle = f->handle;
 254
 255         nest = nla_nest_start(skb, TCA_OPTIONS);
 256         if (nest == NULL)
 257                 goto nla_put_failure;
 258
 259         if (f->res.classid &&
 260             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 261                 goto nla_put_failure;
 262
 263         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 264             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 265                 goto nla_put_failure;
 266
 267         nla_nest_end(skb, nest);
 268
 269         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 270                 goto nla_put_failure;
 271
 272         return skb->len;
 273
 274 nla_put_failure:
 275         nla_nest_cancel(skb, nest);
 276         return -1;
 277 }
 278
 279 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 280         .kind           =       "basic",
 281         .classify       =       basic_classify,
 282         .init           =       basic_init,
 283         .destroy        =       basic_destroy,
 284         .get            =       basic_get,
 285         .change         =       basic_change,
 286         .delete         =       basic_delete,
 287         .walk           =       basic_walk,
 288         .dump           =       basic_dump,
 289         .owner          =       THIS_MODULE,
 290 };
 291
 292 static int __init init_basic(void)
 293 {
 294         return register_tcf_proto_ops(&cls_basic_ops);
 295 }
 296
 297 static void __exit exit_basic(void)
 298 {
 299         unregister_tcf_proto_ops(&cls_basic_ops);
 300 }
 301
 302 module_init(init_basic)
 303 module_exit(exit_basic)
 304 MODULE_LICENSE("GPL");
 305