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/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <linux/mm.h>
  17 #include <linux/errno.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/skbuff.h>
  20 #include <net/act_api.h>
  21 #include <net/pkt_cls.h>
  22
  23 struct basic_head
  24 {
  25         u32                     hgenerator;
  26         struct list_head        flist;
  27 };
  28
  29 struct basic_filter
  30 {
  31         u32                     handle;
  32         struct tcf_exts         exts;
  33         struct tcf_ematch_tree  ematches;
  34         struct tcf_result       res;
  35         struct list_head        link;
  36 };
  37
  38 static struct tcf_ext_map basic_ext_map = {
  39         .action = TCA_BASIC_ACT,
  40         .police = TCA_BASIC_POLICE
  41 };
  42
  43 static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
  44                           struct tcf_result *res)
  45 {
  46         int r;
  47         struct basic_head *head = (struct basic_head *) tp->root;
  48         struct basic_filter *f;
  49
  50         list_for_each_entry(f, &head->flist, link) {
  51                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  52                         continue;
  53                 *res = f->res;
  54                 r = tcf_exts_exec(skb, &f->exts, res);
  55                 if (r < 0)
  56                         continue;
  57                 return r;
  58         }
  59         return -1;
  60 }
  61
  62 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  63 {
  64         unsigned long l = 0UL;
  65         struct basic_head *head = (struct basic_head *) tp->root;
  66         struct basic_filter *f;
  67
  68         if (head == NULL)
  69                 return 0UL;
  70
  71         list_for_each_entry(f, &head->flist, link)
  72                 if (f->handle == handle)
  73                         l = (unsigned long) f;
  74
  75         return l;
  76 }
  77
  78 static void basic_put(struct tcf_proto *tp, unsigned long f)
  79 {
  80 }
  81
  82 static int basic_init(struct tcf_proto *tp)
  83 {
  84         struct basic_head *head;
  85
  86         head = kzalloc(sizeof(*head), GFP_KERNEL);
  87         if (head == NULL)
  88                 return -ENOBUFS;
  89         INIT_LIST_HEAD(&head->flist);
  90         tp->root = head;
  91         return 0;
  92 }
  93
  94 static inline void basic_delete_filter(struct tcf_proto *tp,
  95                                        struct basic_filter *f)
  96 {
  97         tcf_unbind_filter(tp, &f->res);
  98         tcf_exts_destroy(tp, &f->exts);
  99         tcf_em_tree_destroy(tp, &f->ematches);
 100         kfree(f);
 101 }
 102
 103 static void basic_destroy(struct tcf_proto *tp)
 104 {
 105         struct basic_head *head = (struct basic_head *) xchg(&tp->root, NULL);
 106         struct basic_filter *f, *n;
 107
 108         list_for_each_entry_safe(f, n, &head->flist, link) {
 109                 list_del(&f->link);
 110                 basic_delete_filter(tp, f);
 111         }
 112         kfree(head);
 113 }
 114
 115 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 116 {
 117         struct basic_head *head = (struct basic_head *) 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                         tcf_tree_lock(tp);
 123                         list_del(&t->link);
 124                         tcf_tree_unlock(tp);
 125                         basic_delete_filter(tp, t);
 126                         return 0;
 127                 }
 128
 129         return -ENOENT;
 130 }
 131
 132 static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
 133                                   unsigned long base, struct rtattr **tb,
 134                                   struct rtattr *est)
 135 {
 136         int err = -EINVAL;
 137         struct tcf_exts e;
 138         struct tcf_ematch_tree t;
 139
 140         if (tb[TCA_BASIC_CLASSID-1])
 141                 if (RTA_PAYLOAD(tb[TCA_BASIC_CLASSID-1]) < sizeof(u32))
 142                         return err;
 143
 144         err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
 145         if (err < 0)
 146                 return err;
 147
 148         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES-1], &t);
 149         if (err < 0)
 150                 goto errout;
 151
 152         if (tb[TCA_BASIC_CLASSID-1]) {
 153                 f->res.classid = *(u32*)RTA_DATA(tb[TCA_BASIC_CLASSID-1]);
 154                 tcf_bind_filter(tp, &f->res, base);
 155         }
 156
 157         tcf_exts_change(tp, &f->exts, &e);
 158         tcf_em_tree_change(tp, &f->ematches, &t);
 159
 160         return 0;
 161 errout:
 162         tcf_exts_destroy(tp, &e);
 163         return err;
 164 }
 165
 166 static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 167                         struct rtattr **tca, unsigned long *arg)
 168 {
 169         int err = -EINVAL;
 170         struct basic_head *head = (struct basic_head *) tp->root;
 171         struct rtattr *tb[TCA_BASIC_MAX];
 172         struct basic_filter *f = (struct basic_filter *) *arg;
 173
 174         if (tca[TCA_OPTIONS-1] == NULL)
 175                 return -EINVAL;
 176
 177         if (rtattr_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS-1]) < 0)
 178                 return -EINVAL;
 179
 180         if (f != NULL) {
 181                 if (handle && f->handle != handle)
 182                         return -EINVAL;
 183                 return basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 184         }
 185
 186         err = -ENOBUFS;
 187         f = kzalloc(sizeof(*f), GFP_KERNEL);
 188         if (f == NULL)
 189                 goto errout;
 190
 191         err = -EINVAL;
 192         if (handle)
 193                 f->handle = handle;
 194         else {
 195                 unsigned int i = 0x80000000;
 196                 do {
 197                         if (++head->hgenerator == 0x7FFFFFFF)
 198                                 head->hgenerator = 1;
 199                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 200
 201                 if (i <= 0) {
 202                         printk(KERN_ERR "Insufficient number of handles\n");
 203                         goto errout;
 204                 }
 205
 206                 f->handle = head->hgenerator;
 207         }
 208
 209         err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 210         if (err < 0)
 211                 goto errout;
 212
 213         tcf_tree_lock(tp);
 214         list_add(&f->link, &head->flist);
 215         tcf_tree_unlock(tp);
 216         *arg = (unsigned long) f;
 217
 218         return 0;
 219 errout:
 220         if (*arg == 0UL && f)
 221                 kfree(f);
 222
 223         return err;
 224 }
 225
 226 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 227 {
 228         struct basic_head *head = (struct basic_head *) 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 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         unsigned char *b = skb->tail;
 249         struct rtattr *rta;
 250
 251         if (f == NULL)
 252                 return skb->len;
 253
 254         t->tcm_handle = f->handle;
 255
 256         rta = (struct rtattr *) b;
 257         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
 258
 259         if (f->res.classid)
 260                 RTA_PUT(skb, TCA_BASIC_CLASSID, sizeof(u32), &f->res.classid);
 261
 262         if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
 263             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 264                 goto rtattr_failure;
 265
 266         rta->rta_len = (skb->tail - b);
 267         return skb->len;
 268
 269 rtattr_failure:
 270         skb_trim(skb, b - skb->data);
 271         return -1;
 272 }
 273
 274 static struct tcf_proto_ops cls_basic_ops = {
 275         .kind           =       "basic",
 276         .classify       =       basic_classify,
 277         .init           =       basic_init,
 278         .destroy        =       basic_destroy,
 279         .get            =       basic_get,
 280         .put            =       basic_put,
 281         .change         =       basic_change,
 282         .delete         =       basic_delete,
 283         .walk           =       basic_walk,
 284         .dump           =       basic_dump,
 285         .owner          =       THIS_MODULE,
 286 };
 287
 288 static int __init init_basic(void)
 289 {
 290         return register_tcf_proto_ops(&cls_basic_ops);
 291 }
 292
 293 static void __exit exit_basic(void)
 294 {
 295         unregister_tcf_proto_ops(&cls_basic_ops);
 296 }
 297
 298 module_init(init_basic)
 299 module_exit(exit_basic)
 300 MODULE_LICENSE("GPL");
 301