net/sched/cls_fw.c

   1 /*
   2  * net/sched/cls_fw.c   Classifier mapping ipchains' fwmark to traffic class.
   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:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  * Changes:
  12  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
  13  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
  14  * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
  15  *
  16  * JHS: We should remove the CONFIG_NET_CLS_IND from here
  17  * eventually when the meta match extension is made available
  18  *
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/string.h>
  26 #include <linux/errno.h>
  27 #include <linux/skbuff.h>
  28 #include <net/netlink.h>
  29 #include <net/act_api.h>
  30 #include <net/pkt_cls.h>
  31
  32 #define HTSIZE 256
  33
  34 struct fw_head {
  35         u32                     mask;
  36         struct fw_filter __rcu  *ht[HTSIZE];
  37         struct rcu_head         rcu;
  38 };
  39
  40 struct fw_filter {
  41         struct fw_filter __rcu  *next;
  42         u32                     id;
  43         struct tcf_result       res;
  44 #ifdef CONFIG_NET_CLS_IND
  45         int                     ifindex;
  46 #endif /* CONFIG_NET_CLS_IND */
  47         struct tcf_exts         exts;
  48         struct tcf_proto        *tp;
  49         struct rcu_head         rcu;
  50 };
  51
  52 static u32 fw_hash(u32 handle)
  53 {
  54         handle ^= (handle >> 16);
  55         handle ^= (handle >> 8);
  56         return handle % HTSIZE;
  57 }
  58
  59 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  60                           struct tcf_result *res)
  61 {
  62         struct fw_head *head = rcu_dereference_bh(tp->root);
  63         struct fw_filter *f;
  64         int r;
  65         u32 id = skb->mark;
  66
  67         if (head != NULL) {
  68                 id &= head->mask;
  69
  70                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  71                      f = rcu_dereference_bh(f->next)) {
  72                         if (f->id == id) {
  73                                 *res = f->res;
  74 #ifdef CONFIG_NET_CLS_IND
  75                                 if (!tcf_match_indev(skb, f->ifindex))
  76                                         continue;
  77 #endif /* CONFIG_NET_CLS_IND */
  78                                 r = tcf_exts_exec(skb, &f->exts, res);
  79                                 if (r < 0)
  80                                         continue;
  81
  82                                 return r;
  83                         }
  84                 }
  85         } else {
  86                 /* Old method: classify the packet using its skb mark. */
  87                 if (id && (TC_H_MAJ(id) == 0 ||
  88                            !(TC_H_MAJ(id ^ tp->q->handle)))) {
  89                         res->classid = id;
  90                         res->class = 0;
  91                         return 0;
  92                 }
  93         }
  94
  95         return -1;
  96 }
  97
  98 static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
  99 {
 100         struct fw_head *head = rtnl_dereference(tp->root);
 101         struct fw_filter *f;
 102
 103         if (head == NULL)
 104                 return 0;
 105
 106         f = rtnl_dereference(head->ht[fw_hash(handle)]);
 107         for (; f; f = rtnl_dereference(f->next)) {
 108                 if (f->id == handle)
 109                         return (unsigned long)f;
 110         }
 111         return 0;
 112 }
 113
 114 static int fw_init(struct tcf_proto *tp)
 115 {
 116         /* We don't allocate fw_head here, because in the old method
 117          * we don't need it at all.
 118          */
 119         return 0;
 120 }
 121
 122 static void fw_delete_filter(struct rcu_head *head)
 123 {
 124         struct fw_filter *f = container_of(head, struct fw_filter, rcu);
 125
 126         tcf_exts_destroy(&f->exts);
 127         kfree(f);
 128 }
 129
 130 static bool fw_destroy(struct tcf_proto *tp, bool force)
 131 {
 132         struct fw_head *head = rtnl_dereference(tp->root);
 133         struct fw_filter *f;
 134         int h;
 135
 136         if (head == NULL)
 137                 return true;
 138
 139         if (!force) {
 140                 for (h = 0; h < HTSIZE; h++)
 141                         if (rcu_access_pointer(head->ht[h]))
 142                                 return false;
 143         }
 144
 145         for (h = 0; h < HTSIZE; h++) {
 146                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 147                         RCU_INIT_POINTER(head->ht[h],
 148                                          rtnl_dereference(f->next));
 149                         tcf_unbind_filter(tp, &f->res);
 150                         call_rcu(&f->rcu, fw_delete_filter);
 151                 }
 152         }
 153         RCU_INIT_POINTER(tp->root, NULL);
 154         kfree_rcu(head, rcu);
 155         return true;
 156 }
 157
 158 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
 159 {
 160         struct fw_head *head = rtnl_dereference(tp->root);
 161         struct fw_filter *f = (struct fw_filter *)arg;
 162         struct fw_filter __rcu **fp;
 163         struct fw_filter *pfp;
 164
 165         if (head == NULL || f == NULL)
 166                 goto out;
 167
 168         fp = &head->ht[fw_hash(f->id)];
 169
 170         for (pfp = rtnl_dereference(*fp); pfp;
 171              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 172                 if (pfp == f) {
 173                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 174                         tcf_unbind_filter(tp, &f->res);
 175                         call_rcu(&f->rcu, fw_delete_filter);
 176                         return 0;
 177                 }
 178         }
 179 out:
 180         return -EINVAL;
 181 }
 182
 183 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 184         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 185         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 186         [TCA_FW_MASK]           = { .type = NLA_U32 },
 187 };
 188
 189 static int
 190 fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
 191         struct nlattr **tb, struct nlattr **tca, unsigned long base, bool ovr)
 192 {
 193         struct fw_head *head = rtnl_dereference(tp->root);
 194         struct tcf_exts e;
 195         u32 mask;
 196         int err;
 197
 198         err = tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);
 199         if (err < 0)
 200                 return err;
 201         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
 202         if (err < 0)
 203                 goto errout;
 204
 205         if (tb[TCA_FW_CLASSID]) {
 206                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 207                 tcf_bind_filter(tp, &f->res, base);
 208         }
 209
 210 #ifdef CONFIG_NET_CLS_IND
 211         if (tb[TCA_FW_INDEV]) {
 212                 int ret;
 213                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 214                 if (ret < 0) {
 215                         err = ret;
 216                         goto errout;
 217                 }
 218                 f->ifindex = ret;
 219         }
 220 #endif /* CONFIG_NET_CLS_IND */
 221
 222         err = -EINVAL;
 223         if (tb[TCA_FW_MASK]) {
 224                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 225                 if (mask != head->mask)
 226                         goto errout;
 227         } else if (head->mask != 0xFFFFFFFF)
 228                 goto errout;
 229
 230         tcf_exts_change(tp, &f->exts, &e);
 231
 232         return 0;
 233 errout:
 234         tcf_exts_destroy(&e);
 235         return err;
 236 }
 237
 238 static int fw_change(struct net *net, struct sk_buff *in_skb,
 239                      struct tcf_proto *tp, unsigned long base,
 240                      u32 handle,
 241                      struct nlattr **tca,
 242                      unsigned long *arg, bool ovr)
 243 {
 244         struct fw_head *head = rtnl_dereference(tp->root);
 245         struct fw_filter *f = (struct fw_filter *) *arg;
 246         struct nlattr *opt = tca[TCA_OPTIONS];
 247         struct nlattr *tb[TCA_FW_MAX + 1];
 248         int err;
 249
 250         if (!opt)
 251                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 252
 253         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);
 254         if (err < 0)
 255                 return err;
 256
 257         if (f) {
 258                 struct fw_filter *pfp, *fnew;
 259                 struct fw_filter __rcu **fp;
 260
 261                 if (f->id != handle && handle)
 262                         return -EINVAL;
 263
 264                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 265                 if (!fnew)
 266                         return -ENOBUFS;
 267
 268                 fnew->id = f->id;
 269                 fnew->res = f->res;
 270 #ifdef CONFIG_NET_CLS_IND
 271                 fnew->ifindex = f->ifindex;
 272 #endif /* CONFIG_NET_CLS_IND */
 273                 fnew->tp = f->tp;
 274
 275                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 276                 if (err < 0) {
 277                         kfree(fnew);
 278                         return err;
 279                 }
 280
 281                 err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
 282                 if (err < 0) {
 283                         tcf_exts_destroy(&fnew->exts);
 284                         kfree(fnew);
 285                         return err;
 286                 }
 287
 288                 fp = &head->ht[fw_hash(fnew->id)];
 289                 for (pfp = rtnl_dereference(*fp); pfp;
 290                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 291                         if (pfp == f)
 292                                 break;
 293
 294                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 295                 rcu_assign_pointer(*fp, fnew);
 296                 tcf_unbind_filter(tp, &f->res);
 297                 call_rcu(&f->rcu, fw_delete_filter);
 298
 299                 *arg = (unsigned long)fnew;
 300                 return err;
 301         }
 302
 303         if (!handle)
 304                 return -EINVAL;
 305
 306         if (!head) {
 307                 u32 mask = 0xFFFFFFFF;
 308                 if (tb[TCA_FW_MASK])
 309                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 310
 311                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 312                 if (!head)
 313                         return -ENOBUFS;
 314                 head->mask = mask;
 315
 316                 rcu_assign_pointer(tp->root, head);
 317         }
 318
 319         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 320         if (f == NULL)
 321                 return -ENOBUFS;
 322
 323         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 324         if (err < 0)
 325                 goto errout;
 326         f->id = handle;
 327         f->tp = tp;
 328
 329         err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
 330         if (err < 0)
 331                 goto errout;
 332
 333         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 334         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 335
 336         *arg = (unsigned long)f;
 337         return 0;
 338
 339 errout:
 340         tcf_exts_destroy(&f->exts);
 341         kfree(f);
 342         return err;
 343 }
 344
 345 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 346 {
 347         struct fw_head *head = rtnl_dereference(tp->root);
 348         int h;
 349
 350         if (head == NULL)
 351                 arg->stop = 1;
 352
 353         if (arg->stop)
 354                 return;
 355
 356         for (h = 0; h < HTSIZE; h++) {
 357                 struct fw_filter *f;
 358
 359                 for (f = rtnl_dereference(head->ht[h]); f;
 360                      f = rtnl_dereference(f->next)) {
 361                         if (arg->count < arg->skip) {
 362                                 arg->count++;
 363                                 continue;
 364                         }
 365                         if (arg->fn(tp, (unsigned long)f, arg) < 0) {
 366                                 arg->stop = 1;
 367                                 return;
 368                         }
 369                         arg->count++;
 370                 }
 371         }
 372 }
 373
 374 static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 375                    struct sk_buff *skb, struct tcmsg *t)
 376 {
 377         struct fw_head *head = rtnl_dereference(tp->root);
 378         struct fw_filter *f = (struct fw_filter *)fh;
 379         struct nlattr *nest;
 380
 381         if (f == NULL)
 382                 return skb->len;
 383
 384         t->tcm_handle = f->id;
 385
 386         if (!f->res.classid && !tcf_exts_is_available(&f->exts))
 387                 return skb->len;
 388
 389         nest = nla_nest_start(skb, TCA_OPTIONS);
 390         if (nest == NULL)
 391                 goto nla_put_failure;
 392
 393         if (f->res.classid &&
 394             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 395                 goto nla_put_failure;
 396 #ifdef CONFIG_NET_CLS_IND
 397         if (f->ifindex) {
 398                 struct net_device *dev;
 399                 dev = __dev_get_by_index(net, f->ifindex);
 400                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 401                         goto nla_put_failure;
 402         }
 403 #endif /* CONFIG_NET_CLS_IND */
 404         if (head->mask != 0xFFFFFFFF &&
 405             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 406                 goto nla_put_failure;
 407
 408         if (tcf_exts_dump(skb, &f->exts) < 0)
 409                 goto nla_put_failure;
 410
 411         nla_nest_end(skb, nest);
 412
 413         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 414                 goto nla_put_failure;
 415
 416         return skb->len;
 417
 418 nla_put_failure:
 419         nla_nest_cancel(skb, nest);
 420         return -1;
 421 }
 422
 423 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 424         .kind           =       "fw",
 425         .classify       =       fw_classify,
 426         .init           =       fw_init,
 427         .destroy        =       fw_destroy,
 428         .get            =       fw_get,
 429         .change         =       fw_change,
 430         .delete         =       fw_delete,
 431         .walk           =       fw_walk,
 432         .dump           =       fw_dump,
 433         .owner          =       THIS_MODULE,
 434 };
 435
 436 static int __init init_fw(void)
 437 {
 438         return register_tcf_proto_ops(&cls_fw_ops);
 439 }
 440
 441 static void __exit exit_fw(void)
 442 {
 443         unregister_tcf_proto_ops(&cls_fw_ops);
 444 }
 445
 446 module_init(init_fw)
 447 module_exit(exit_fw)
 448 MODULE_LICENSE("GPL");