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 void *basic_get(struct tcf_proto *tp, u32 handle)
  60 {
  61         struct basic_head *head = rtnl_dereference(tp->root);
  62         struct basic_filter *f;
  63
  64         list_for_each_entry(f, &head->flist, link) {
  65                 if (f->handle == handle) {
  66                         return f;
  67                 }
  68         }
  69
  70         return NULL;
  71 }
  72
  73 static int basic_init(struct tcf_proto *tp)
  74 {
  75         struct basic_head *head;
  76
  77         head = kzalloc(sizeof(*head), GFP_KERNEL);
  78         if (head == NULL)
  79                 return -ENOBUFS;
  80         INIT_LIST_HEAD(&head->flist);
  81         rcu_assign_pointer(tp->root, head);
  82         return 0;
  83 }
  84
  85 static void basic_delete_filter(struct rcu_head *head)
  86 {
  87         struct basic_filter *f = container_of(head, struct basic_filter, rcu);
  88
  89         tcf_exts_destroy(&f->exts);
  90         tcf_em_tree_destroy(&f->ematches);
  91         kfree(f);
  92 }
  93
  94 static void basic_destroy(struct tcf_proto *tp)
  95 {
  96         struct basic_head *head = rtnl_dereference(tp->root);
  97         struct basic_filter *f, *n;
  98
  99         list_for_each_entry_safe(f, n, &head->flist, link) {
 100                 list_del_rcu(&f->link);
 101                 tcf_unbind_filter(tp, &f->res);
 102                 call_rcu(&f->rcu, basic_delete_filter);
 103         }
 104         kfree_rcu(head, rcu);
 105 }
 106
 107 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last)
 108 {
 109         struct basic_head *head = rtnl_dereference(tp->root);
 110         struct basic_filter *f = arg;
 111
 112         list_del_rcu(&f->link);
 113         tcf_unbind_filter(tp, &f->res);
 114         call_rcu(&f->rcu, basic_delete_filter);
 115         *last = list_empty(&head->flist);
 116         return 0;
 117 }
 118
 119 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
 120         [TCA_BASIC_CLASSID]     = { .type = NLA_U32 },
 121         [TCA_BASIC_EMATCHES]    = { .type = NLA_NESTED },
 122 };
 123
 124 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
 125                            struct basic_filter *f, unsigned long base,
 126                            struct nlattr **tb,
 127                            struct nlattr *est, bool ovr)
 128 {
 129         int err;
 130
 131         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 132         if (err < 0)
 133                 return err;
 134
 135         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
 136         if (err < 0)
 137                 return err;
 138
 139         if (tb[TCA_BASIC_CLASSID]) {
 140                 f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
 141                 tcf_bind_filter(tp, &f->res, base);
 142         }
 143
 144         f->tp = tp;
 145         return 0;
 146 }
 147
 148 static int basic_change(struct net *net, struct sk_buff *in_skb,
 149                         struct tcf_proto *tp, unsigned long base, u32 handle,
 150                         struct nlattr **tca, void **arg, bool ovr)
 151 {
 152         int err;
 153         struct basic_head *head = rtnl_dereference(tp->root);
 154         struct nlattr *tb[TCA_BASIC_MAX + 1];
 155         struct basic_filter *fold = (struct basic_filter *) *arg;
 156         struct basic_filter *fnew;
 157
 158         if (tca[TCA_OPTIONS] == NULL)
 159                 return -EINVAL;
 160
 161         err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
 162                                basic_policy, NULL);
 163         if (err < 0)
 164                 return err;
 165
 166         if (fold != NULL) {
 167                 if (handle && fold->handle != handle)
 168                         return -EINVAL;
 169         }
 170
 171         fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
 172         if (!fnew)
 173                 return -ENOBUFS;
 174
 175         err = tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
 176         if (err < 0)
 177                 goto errout;
 178
 179         err = -EINVAL;
 180         if (handle) {
 181                 fnew->handle = handle;
 182         } else if (fold) {
 183                 fnew->handle = fold->handle;
 184         } else {
 185                 unsigned int i = 0x80000000;
 186                 do {
 187                         if (++head->hgenerator == 0x7FFFFFFF)
 188                                 head->hgenerator = 1;
 189                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 190
 191                 if (i <= 0) {
 192                         pr_err("Insufficient number of handles\n");
 193                         goto errout;
 194                 }
 195
 196                 fnew->handle = head->hgenerator;
 197         }
 198
 199         err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
 200         if (err < 0)
 201                 goto errout;
 202
 203         *arg = fnew;
 204
 205         if (fold) {
 206                 list_replace_rcu(&fold->link, &fnew->link);
 207                 tcf_unbind_filter(tp, &fold->res);
 208                 call_rcu(&fold->rcu, basic_delete_filter);
 209         } else {
 210                 list_add_rcu(&fnew->link, &head->flist);
 211         }
 212
 213         return 0;
 214 errout:
 215         tcf_exts_destroy(&fnew->exts);
 216         kfree(fnew);
 217         return err;
 218 }
 219
 220 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 221 {
 222         struct basic_head *head = rtnl_dereference(tp->root);
 223         struct basic_filter *f;
 224
 225         list_for_each_entry(f, &head->flist, link) {
 226                 if (arg->count < arg->skip)
 227                         goto skip;
 228
 229                 if (arg->fn(tp, f, arg) < 0) {
 230                         arg->stop = 1;
 231                         break;
 232                 }
 233 skip:
 234                 arg->count++;
 235         }
 236 }
 237
 238 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 239 {
 240         struct basic_filter *f = fh;
 241
 242         if (f && f->res.classid == classid)
 243                 f->res.class = cl;
 244 }
 245
 246 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 247                       struct sk_buff *skb, struct tcmsg *t)
 248 {
 249         struct basic_filter *f = fh;
 250         struct nlattr *nest;
 251
 252         if (f == NULL)
 253                 return skb->len;
 254
 255         t->tcm_handle = f->handle;
 256
 257         nest = nla_nest_start(skb, TCA_OPTIONS);
 258         if (nest == NULL)
 259                 goto nla_put_failure;
 260
 261         if (f->res.classid &&
 262             nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 263                 goto nla_put_failure;
 264
 265         if (tcf_exts_dump(skb, &f->exts) < 0 ||
 266             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 267                 goto nla_put_failure;
 268
 269         nla_nest_end(skb, nest);
 270
 271         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 272                 goto nla_put_failure;
 273
 274         return skb->len;
 275
 276 nla_put_failure:
 277         nla_nest_cancel(skb, nest);
 278         return -1;
 279 }
 280
 281 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
 282         .kind           =       "basic",
 283         .classify       =       basic_classify,
 284         .init           =       basic_init,
 285         .destroy        =       basic_destroy,
 286         .get            =       basic_get,
 287         .change         =       basic_change,
 288         .delete         =       basic_delete,
 289         .walk           =       basic_walk,
 290         .dump           =       basic_dump,
 291         .bind_class     =       basic_bind_class,
 292         .owner          =       THIS_MODULE,
 293 };
 294
 295 static int __init init_basic(void)
 296 {
 297         return register_tcf_proto_ops(&cls_basic_ops);
 298 }
 299
 300 static void __exit exit_basic(void)
 301 {
 302         unregister_tcf_proto_ops(&cls_basic_ops);
 303 }
 304
 305 module_init(init_basic)
 306 module_exit(exit_basic)
 307 MODULE_LICENSE("GPL");
 308