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 #include <net/sch_generic.h>
  32
  33 #define HTSIZE 256
  34
  35 struct fw_head {
  36         u32                     mask;
  37         struct fw_filter __rcu  *ht[HTSIZE];
  38         struct rcu_head         rcu;
  39 };
  40
  41 struct fw_filter {
  42         struct fw_filter __rcu  *next;
  43         u32                     id;
  44         struct tcf_result       res;
  45 #ifdef CONFIG_NET_CLS_IND
  46         int                     ifindex;
  47 #endif /* CONFIG_NET_CLS_IND */
  48         struct tcf_exts         exts;
  49         struct tcf_proto        *tp;
  50         union {
  51                 struct work_struct      work;
  52                 struct rcu_head         rcu;
  53         };
  54 };
  55
  56 static u32 fw_hash(u32 handle)
  57 {
  58         handle ^= (handle >> 16);
  59         handle ^= (handle >> 8);
  60         return handle % HTSIZE;
  61 }
  62
  63 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  64                        struct tcf_result *res)
  65 {
  66         struct fw_head *head = rcu_dereference_bh(tp->root);
  67         struct fw_filter *f;
  68         int r;
  69         u32 id = skb->mark;
  70
  71         if (head != NULL) {
  72                 id &= head->mask;
  73
  74                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  75                      f = rcu_dereference_bh(f->next)) {
  76                         if (f->id == id) {
  77                                 *res = f->res;
  78 #ifdef CONFIG_NET_CLS_IND
  79                                 if (!tcf_match_indev(skb, f->ifindex))
  80                                         continue;
  81 #endif /* CONFIG_NET_CLS_IND */
  82                                 r = tcf_exts_exec(skb, &f->exts, res);
  83                                 if (r < 0)
  84                                         continue;
  85
  86                                 return r;
  87                         }
  88                 }
  89         } else {
  90                 struct Qdisc *q = tcf_block_q(tp->chain->block);
  91
  92                 /* Old method: classify the packet using its skb mark. */
  93                 if (id && (TC_H_MAJ(id) == 0 ||
  94                            !(TC_H_MAJ(id ^ q->handle)))) {
  95                         res->classid = id;
  96                         res->class = 0;
  97                         return 0;
  98                 }
  99         }
 100
 101         return -1;
 102 }
 103
 104 static void *fw_get(struct tcf_proto *tp, u32 handle)
 105 {
 106         struct fw_head *head = rtnl_dereference(tp->root);
 107         struct fw_filter *f;
 108
 109         if (head == NULL)
 110                 return NULL;
 111
 112         f = rtnl_dereference(head->ht[fw_hash(handle)]);
 113         for (; f; f = rtnl_dereference(f->next)) {
 114                 if (f->id == handle)
 115                         return f;
 116         }
 117         return NULL;
 118 }
 119
 120 static int fw_init(struct tcf_proto *tp)
 121 {
 122         /* We don't allocate fw_head here, because in the old method
 123          * we don't need it at all.
 124          */
 125         return 0;
 126 }
 127
 128 static void __fw_delete_filter(struct fw_filter *f)
 129 {
 130         tcf_exts_destroy(&f->exts);
 131         tcf_exts_put_net(&f->exts);
 132         kfree(f);
 133 }
 134
 135 static void fw_delete_filter_work(struct work_struct *work)
 136 {
 137         struct fw_filter *f = container_of(work, struct fw_filter, work);
 138
 139         rtnl_lock();
 140         __fw_delete_filter(f);
 141         rtnl_unlock();
 142 }
 143
 144 static void fw_delete_filter(struct rcu_head *head)
 145 {
 146         struct fw_filter *f = container_of(head, struct fw_filter, rcu);
 147
 148         INIT_WORK(&f->work, fw_delete_filter_work);
 149         tcf_queue_work(&f->work);
 150 }
 151
 152 static void fw_destroy(struct tcf_proto *tp)
 153 {
 154         struct fw_head *head = rtnl_dereference(tp->root);
 155         struct fw_filter *f;
 156         int h;
 157
 158         if (head == NULL)
 159                 return;
 160
 161         for (h = 0; h < HTSIZE; h++) {
 162                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 163                         RCU_INIT_POINTER(head->ht[h],
 164                                          rtnl_dereference(f->next));
 165                         tcf_unbind_filter(tp, &f->res);
 166                         if (tcf_exts_get_net(&f->exts))
 167                                 call_rcu(&f->rcu, fw_delete_filter);
 168                         else
 169                                 __fw_delete_filter(f);
 170                 }
 171         }
 172         kfree_rcu(head, rcu);
 173 }
 174
 175 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
 176 {
 177         struct fw_head *head = rtnl_dereference(tp->root);
 178         struct fw_filter *f = arg;
 179         struct fw_filter __rcu **fp;
 180         struct fw_filter *pfp;
 181         int ret = -EINVAL;
 182         int h;
 183
 184         if (head == NULL || f == NULL)
 185                 goto out;
 186
 187         fp = &head->ht[fw_hash(f->id)];
 188
 189         for (pfp = rtnl_dereference(*fp); pfp;
 190              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 191                 if (pfp == f) {
 192                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 193                         tcf_unbind_filter(tp, &f->res);
 194                         tcf_exts_get_net(&f->exts);
 195                         call_rcu(&f->rcu, fw_delete_filter);
 196                         ret = 0;
 197                         break;
 198                 }
 199         }
 200
 201         *last = true;
 202         for (h = 0; h < HTSIZE; h++) {
 203                 if (rcu_access_pointer(head->ht[h])) {
 204                         *last = false;
 205                         break;
 206                 }
 207         }
 208
 209 out:
 210         return ret;
 211 }
 212
 213 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 214         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 215         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 216         [TCA_FW_MASK]           = { .type = NLA_U32 },
 217 };
 218
 219 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 220                         struct fw_filter *f, struct nlattr **tb,
 221                         struct nlattr **tca, unsigned long base, bool ovr)
 222 {
 223         struct fw_head *head = rtnl_dereference(tp->root);
 224         u32 mask;
 225         int err;
 226
 227         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
 228         if (err < 0)
 229                 return err;
 230
 231         if (tb[TCA_FW_CLASSID]) {
 232                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 233                 tcf_bind_filter(tp, &f->res, base);
 234         }
 235
 236 #ifdef CONFIG_NET_CLS_IND
 237         if (tb[TCA_FW_INDEV]) {
 238                 int ret;
 239                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 240                 if (ret < 0)
 241                         return ret;
 242                 f->ifindex = ret;
 243         }
 244 #endif /* CONFIG_NET_CLS_IND */
 245
 246         err = -EINVAL;
 247         if (tb[TCA_FW_MASK]) {
 248                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 249                 if (mask != head->mask)
 250                         return err;
 251         } else if (head->mask != 0xFFFFFFFF)
 252                 return err;
 253
 254         return 0;
 255 }
 256
 257 static int fw_change(struct net *net, struct sk_buff *in_skb,
 258                      struct tcf_proto *tp, unsigned long base,
 259                      u32 handle, struct nlattr **tca, void **arg,
 260                      bool ovr)
 261 {
 262         struct fw_head *head = rtnl_dereference(tp->root);
 263         struct fw_filter *f = *arg;
 264         struct nlattr *opt = tca[TCA_OPTIONS];
 265         struct nlattr *tb[TCA_FW_MAX + 1];
 266         int err;
 267
 268         if (!opt)
 269                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 270
 271         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 272         if (err < 0)
 273                 return err;
 274
 275         if (f) {
 276                 struct fw_filter *pfp, *fnew;
 277                 struct fw_filter __rcu **fp;
 278
 279                 if (f->id != handle && handle)
 280                         return -EINVAL;
 281
 282                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 283                 if (!fnew)
 284                         return -ENOBUFS;
 285
 286                 fnew->id = f->id;
 287                 fnew->res = f->res;
 288 #ifdef CONFIG_NET_CLS_IND
 289                 fnew->ifindex = f->ifindex;
 290 #endif /* CONFIG_NET_CLS_IND */
 291                 fnew->tp = f->tp;
 292
 293                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 294                 if (err < 0) {
 295                         kfree(fnew);
 296                         return err;
 297                 }
 298
 299                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
 300                 if (err < 0) {
 301                         tcf_exts_destroy(&fnew->exts);
 302                         kfree(fnew);
 303                         return err;
 304                 }
 305
 306                 fp = &head->ht[fw_hash(fnew->id)];
 307                 for (pfp = rtnl_dereference(*fp); pfp;
 308                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 309                         if (pfp == f)
 310                                 break;
 311
 312                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 313                 rcu_assign_pointer(*fp, fnew);
 314                 tcf_unbind_filter(tp, &f->res);
 315                 tcf_exts_get_net(&f->exts);
 316                 call_rcu(&f->rcu, fw_delete_filter);
 317
 318                 *arg = fnew;
 319                 return err;
 320         }
 321
 322         if (!handle)
 323                 return -EINVAL;
 324
 325         if (!head) {
 326                 u32 mask = 0xFFFFFFFF;
 327                 if (tb[TCA_FW_MASK])
 328                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 329
 330                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 331                 if (!head)
 332                         return -ENOBUFS;
 333                 head->mask = mask;
 334
 335                 rcu_assign_pointer(tp->root, head);
 336         }
 337
 338         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 339         if (f == NULL)
 340                 return -ENOBUFS;
 341
 342         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 343         if (err < 0)
 344                 goto errout;
 345         f->id = handle;
 346         f->tp = tp;
 347
 348         err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
 349         if (err < 0)
 350                 goto errout;
 351
 352         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 353         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 354
 355         *arg = f;
 356         return 0;
 357
 358 errout:
 359         tcf_exts_destroy(&f->exts);
 360         kfree(f);
 361         return err;
 362 }
 363
 364 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 365 {
 366         struct fw_head *head = rtnl_dereference(tp->root);
 367         int h;
 368
 369         if (head == NULL)
 370                 arg->stop = 1;
 371
 372         if (arg->stop)
 373                 return;
 374
 375         for (h = 0; h < HTSIZE; h++) {
 376                 struct fw_filter *f;
 377
 378                 for (f = rtnl_dereference(head->ht[h]); f;
 379                      f = rtnl_dereference(f->next)) {
 380                         if (arg->count < arg->skip) {
 381                                 arg->count++;
 382                                 continue;
 383                         }
 384                         if (arg->fn(tp, f, arg) < 0) {
 385                                 arg->stop = 1;
 386                                 return;
 387                         }
 388                         arg->count++;
 389                 }
 390         }
 391 }
 392
 393 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 394                    struct sk_buff *skb, struct tcmsg *t)
 395 {
 396         struct fw_head *head = rtnl_dereference(tp->root);
 397         struct fw_filter *f = fh;
 398         struct nlattr *nest;
 399
 400         if (f == NULL)
 401                 return skb->len;
 402
 403         t->tcm_handle = f->id;
 404
 405         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 406                 return skb->len;
 407
 408         nest = nla_nest_start(skb, TCA_OPTIONS);
 409         if (nest == NULL)
 410                 goto nla_put_failure;
 411
 412         if (f->res.classid &&
 413             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 414                 goto nla_put_failure;
 415 #ifdef CONFIG_NET_CLS_IND
 416         if (f->ifindex) {
 417                 struct net_device *dev;
 418                 dev = __dev_get_by_index(net, f->ifindex);
 419                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 420                         goto nla_put_failure;
 421         }
 422 #endif /* CONFIG_NET_CLS_IND */
 423         if (head->mask != 0xFFFFFFFF &&
 424             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 425                 goto nla_put_failure;
 426
 427         if (tcf_exts_dump(skb, &f->exts) < 0)
 428                 goto nla_put_failure;
 429
 430         nla_nest_end(skb, nest);
 431
 432         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 433                 goto nla_put_failure;
 434
 435         return skb->len;
 436
 437 nla_put_failure:
 438         nla_nest_cancel(skb, nest);
 439         return -1;
 440 }
 441
 442 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 443 {
 444         struct fw_filter *f = fh;
 445
 446         if (f && f->res.classid == classid)
 447                 f->res.class = cl;
 448 }
 449
 450 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 451         .kind           =       "fw",
 452         .classify       =       fw_classify,
 453         .init           =       fw_init,
 454         .destroy        =       fw_destroy,
 455         .get            =       fw_get,
 456         .change         =       fw_change,
 457         .delete         =       fw_delete,
 458         .walk           =       fw_walk,
 459         .dump           =       fw_dump,
 460         .bind_class     =       fw_bind_class,
 461         .owner          =       THIS_MODULE,
 462 };
 463
 464 static int __init init_fw(void)
 465 {
 466         return register_tcf_proto_ops(&cls_fw_ops);
 467 }
 468
 469 static void __exit exit_fw(void)
 470 {
 471         unregister_tcf_proto_ops(&cls_fw_ops);
 472 }
 473
 474 module_init(init_fw)
 475 module_exit(exit_fw)
 476 MODULE_LICENSE("GPL");