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   1 /*
   2  * net/sched/cls_api.c  Packet classifier API.
   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  *
  13  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
  14  *
  15  */
  16
  17 #include <asm/uaccess.h>
  18 #include <asm/system.h>
  19 #include <linux/bitops.h>
  20 #include <linux/config.h>
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/string.h>
  26 #include <linux/mm.h>
  27 #include <linux/socket.h>
  28 #include <linux/sockios.h>
  29 #include <linux/in.h>
  30 #include <linux/errno.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/rtnetlink.h>
  35 #include <linux/init.h>
  36 #include <linux/kmod.h>
  37 #include <net/sock.h>
  38 #include <net/pkt_sched.h>
  39 #include <net/pkt_cls.h>
  40
  41 #if 0 /* control */
  42 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  43 #else
  44 #define DPRINTK(format,args...)
  45 #endif
  46
  47 /* The list of all installed classifier types */
  48
  49 static struct tcf_proto_ops *tcf_proto_base;
  50
  51 /* Protects list of registered TC modules. It is pure SMP lock. */
  52 static DEFINE_RWLOCK(cls_mod_lock);
  53
  54 /* Find classifier type by string name */
  55
  56 static struct tcf_proto_ops * tcf_proto_lookup_ops(struct rtattr *kind)
  57 {
  58         struct tcf_proto_ops *t = NULL;
  59
  60         if (kind) {
  61                 read_lock(&cls_mod_lock);
  62                 for (t = tcf_proto_base; t; t = t->next) {
  63                         if (rtattr_strcmp(kind, t->kind) == 0) {
  64                                 if (!try_module_get(t->owner))
  65                                         t = NULL;
  66                                 break;
  67                         }
  68                 }
  69                 read_unlock(&cls_mod_lock);
  70         }
  71         return t;
  72 }
  73
  74 /* Register(unregister) new classifier type */
  75
  76 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  77 {
  78         struct tcf_proto_ops *t, **tp;
  79         int rc = -EEXIST;
  80
  81         write_lock(&cls_mod_lock);
  82         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  83                 if (!strcmp(ops->kind, t->kind))
  84                         goto out;
  85
  86         ops->next = NULL;
  87         *tp = ops;
  88         rc = 0;
  89 out:
  90         write_unlock(&cls_mod_lock);
  91         return rc;
  92 }
  93
  94 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  95 {
  96         struct tcf_proto_ops *t, **tp;
  97         int rc = -ENOENT;
  98
  99         write_lock(&cls_mod_lock);
 100         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
 101                 if (t == ops)
 102                         break;
 103
 104         if (!t)
 105                 goto out;
 106         *tp = t->next;
 107         rc = 0;
 108 out:
 109         write_unlock(&cls_mod_lock);
 110         return rc;
 111 }
 112
 113 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 114                           struct tcf_proto *tp, unsigned long fh, int event);
 115
 116
 117 /* Select new prio value from the range, managed by kernel. */
 118
 119 static __inline__ u32 tcf_auto_prio(struct tcf_proto *tp)
 120 {
 121         u32 first = TC_H_MAKE(0xC0000000U,0U);
 122
 123         if (tp)
 124                 first = tp->prio-1;
 125
 126         return first;
 127 }
 128
 129 /* Add/change/delete/get a filter node */
 130
 131 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 132 {
 133         struct rtattr **tca;
 134         struct tcmsg *t;
 135         u32 protocol;
 136         u32 prio;
 137         u32 nprio;
 138         u32 parent;
 139         struct net_device *dev;
 140         struct Qdisc  *q;
 141         struct tcf_proto **back, **chain;
 142         struct tcf_proto *tp;
 143         struct tcf_proto_ops *tp_ops;
 144         struct Qdisc_class_ops *cops;
 145         unsigned long cl;
 146         unsigned long fh;
 147         int err;
 148
 149 replay:
 150         tca = arg;
 151         t = NLMSG_DATA(n);
 152         protocol = TC_H_MIN(t->tcm_info);
 153         prio = TC_H_MAJ(t->tcm_info);
 154         nprio = prio;
 155         parent = t->tcm_parent;
 156         cl = 0;
 157
 158         if (prio == 0) {
 159                 /* If no priority is given, user wants we allocated it. */
 160                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 161                         return -ENOENT;
 162                 prio = TC_H_MAKE(0x80000000U,0U);
 163         }
 164
 165         /* Find head of filter chain. */
 166
 167         /* Find link */
 168         if ((dev = __dev_get_by_index(t->tcm_ifindex)) == NULL)
 169                 return -ENODEV;
 170
 171         /* Find qdisc */
 172         if (!parent) {
 173                 q = dev->qdisc_sleeping;
 174                 parent = q->handle;
 175         } else if ((q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent))) == NULL)
 176                 return -EINVAL;
 177
 178         /* Is it classful? */
 179         if ((cops = q->ops->cl_ops) == NULL)
 180                 return -EINVAL;
 181
 182         /* Do we search for filter, attached to class? */
 183         if (TC_H_MIN(parent)) {
 184                 cl = cops->get(q, parent);
 185                 if (cl == 0)
 186                         return -ENOENT;
 187         }
 188
 189         /* And the last stroke */
 190         chain = cops->tcf_chain(q, cl);
 191         err = -EINVAL;
 192         if (chain == NULL)
 193                 goto errout;
 194
 195         /* Check the chain for existence of proto-tcf with this priority */
 196         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 197                 if (tp->prio >= prio) {
 198                         if (tp->prio == prio) {
 199                                 if (!nprio || (tp->protocol != protocol && protocol))
 200                                         goto errout;
 201                         } else
 202                                 tp = NULL;
 203                         break;
 204                 }
 205         }
 206
 207         if (tp == NULL) {
 208                 /* Proto-tcf does not exist, create new one */
 209
 210                 if (tca[TCA_KIND-1] == NULL || !protocol)
 211                         goto errout;
 212
 213                 err = -ENOENT;
 214                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 215                         goto errout;
 216
 217
 218                 /* Create new proto tcf */
 219
 220                 err = -ENOBUFS;
 221                 if ((tp = kmalloc(sizeof(*tp), GFP_KERNEL)) == NULL)
 222                         goto errout;
 223                 err = -EINVAL;
 224                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
 225                 if (tp_ops == NULL) {
 226 #ifdef CONFIG_KMOD
 227                         struct rtattr *kind = tca[TCA_KIND-1];
 228                         char name[IFNAMSIZ];
 229
 230                         if (kind != NULL &&
 231                             rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 232                                 rtnl_unlock();
 233                                 request_module("cls_%s", name);
 234                                 rtnl_lock();
 235                                 tp_ops = tcf_proto_lookup_ops(kind);
 236                                 /* We dropped the RTNL semaphore in order to
 237                                  * perform the module load.  So, even if we
 238                                  * succeeded in loading the module we have to
 239                                  * replay the request.  We indicate this using
 240                                  * -EAGAIN.
 241                                  */
 242                                 if (tp_ops != NULL) {
 243                                         module_put(tp_ops->owner);
 244                                         err = -EAGAIN;
 245                                 }
 246                         }
 247 #endif
 248                         kfree(tp);
 249                         goto errout;
 250                 }
 251                 memset(tp, 0, sizeof(*tp));
 252                 tp->ops = tp_ops;
 253                 tp->protocol = protocol;
 254                 tp->prio = nprio ? : tcf_auto_prio(*back);
 255                 tp->q = q;
 256                 tp->classify = tp_ops->classify;
 257                 tp->classid = parent;
 258                 if ((err = tp_ops->init(tp)) != 0) {
 259                         module_put(tp_ops->owner);
 260                         kfree(tp);
 261                         goto errout;
 262                 }
 263
 264                 qdisc_lock_tree(dev);
 265                 tp->next = *back;
 266                 *back = tp;
 267                 qdisc_unlock_tree(dev);
 268
 269         } else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
 270                 goto errout;
 271
 272         fh = tp->ops->get(tp, t->tcm_handle);
 273
 274         if (fh == 0) {
 275                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 276                         qdisc_lock_tree(dev);
 277                         *back = tp->next;
 278                         qdisc_unlock_tree(dev);
 279
 280                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 281                         tcf_destroy(tp);
 282                         err = 0;
 283                         goto errout;
 284                 }
 285
 286                 err = -ENOENT;
 287                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 288                         goto errout;
 289         } else {
 290                 switch (n->nlmsg_type) {
 291                 case RTM_NEWTFILTER:
 292                         err = -EEXIST;
 293                         if (n->nlmsg_flags&NLM_F_EXCL)
 294                                 goto errout;
 295                         break;
 296                 case RTM_DELTFILTER:
 297                         err = tp->ops->delete(tp, fh);
 298                         if (err == 0)
 299                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 300                         goto errout;
 301                 case RTM_GETTFILTER:
 302                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 303                         goto errout;
 304                 default:
 305                         err = -EINVAL;
 306                         goto errout;
 307                 }
 308         }
 309
 310         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 311         if (err == 0)
 312                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 313
 314 errout:
 315         if (cl)
 316                 cops->put(q, cl);
 317         if (err == -EAGAIN)
 318                 /* Replay the request. */
 319                 goto replay;
 320         return err;
 321 }
 322
 323 static int
 324 tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, unsigned long fh,
 325               u32 pid, u32 seq, unsigned flags, int event)
 326 {
 327         struct tcmsg *tcm;
 328         struct nlmsghdr  *nlh;
 329         unsigned char    *b = skb->tail;
 330
 331         nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(*tcm));
 332         nlh->nlmsg_flags = flags;
 333         tcm = NLMSG_DATA(nlh);
 334         tcm->tcm_family = AF_UNSPEC;
 335         tcm->tcm_ifindex = tp->q->dev->ifindex;
 336         tcm->tcm_parent = tp->classid;
 337         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 338         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
 339         tcm->tcm_handle = fh;
 340         if (RTM_DELTFILTER != event) {
 341                 tcm->tcm_handle = 0;
 342                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 343                         goto rtattr_failure;
 344         }
 345         nlh->nlmsg_len = skb->tail - b;
 346         return skb->len;
 347
 348 nlmsg_failure:
 349 rtattr_failure:
 350         skb_trim(skb, b - skb->data);
 351         return -1;
 352 }
 353
 354 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 355                           struct tcf_proto *tp, unsigned long fh, int event)
 356 {
 357         struct sk_buff *skb;
 358         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 359
 360         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 361         if (!skb)
 362                 return -ENOBUFS;
 363
 364         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 365                 kfree_skb(skb);
 366                 return -EINVAL;
 367         }
 368
 369         return rtnetlink_send(skb, pid, RTMGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
 370 }
 371
 372 struct tcf_dump_args
 373 {
 374         struct tcf_walker w;
 375         struct sk_buff *skb;
 376         struct netlink_callback *cb;
 377 };
 378
 379 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, struct tcf_walker *arg)
 380 {
 381         struct tcf_dump_args *a = (void*)arg;
 382
 383         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 384                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 385 }
 386
 387 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 388 {
 389         int t;
 390         int s_t;
 391         struct net_device *dev;
 392         struct Qdisc *q;
 393         struct tcf_proto *tp, **chain;
 394         struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
 395         unsigned long cl = 0;
 396         struct Qdisc_class_ops *cops;
 397         struct tcf_dump_args arg;
 398
 399         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 400                 return skb->len;
 401         if ((dev = dev_get_by_index(tcm->tcm_ifindex)) == NULL)
 402                 return skb->len;
 403
 404         read_lock_bh(&qdisc_tree_lock);
 405         if (!tcm->tcm_parent)
 406                 q = dev->qdisc_sleeping;
 407         else
 408                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 409         if (!q)
 410                 goto out;
 411         if ((cops = q->ops->cl_ops) == NULL)
 412                 goto errout;
 413         if (TC_H_MIN(tcm->tcm_parent)) {
 414                 cl = cops->get(q, tcm->tcm_parent);
 415                 if (cl == 0)
 416                         goto errout;
 417         }
 418         chain = cops->tcf_chain(q, cl);
 419         if (chain == NULL)
 420                 goto errout;
 421
 422         s_t = cb->args[0];
 423
 424         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 425                 if (t < s_t) continue;
 426                 if (TC_H_MAJ(tcm->tcm_info) &&
 427                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 428                         continue;
 429                 if (TC_H_MIN(tcm->tcm_info) &&
 430                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 431                         continue;
 432                 if (t > s_t)
 433                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 434                 if (cb->args[1] == 0) {
 435                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 436                                           cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER) <= 0) {
 437                                 break;
 438                         }
 439                         cb->args[1] = 1;
 440                 }
 441                 if (tp->ops->walk == NULL)
 442                         continue;
 443                 arg.w.fn = tcf_node_dump;
 444                 arg.skb = skb;
 445                 arg.cb = cb;
 446                 arg.w.stop = 0;
 447                 arg.w.skip = cb->args[1]-1;
 448                 arg.w.count = 0;
 449                 tp->ops->walk(tp, &arg.w);
 450                 cb->args[1] = arg.w.count+1;
 451                 if (arg.w.stop)
 452                         break;
 453         }
 454
 455         cb->args[0] = t;
 456
 457 errout:
 458         if (cl)
 459                 cops->put(q, cl);
 460 out:
 461         read_unlock_bh(&qdisc_tree_lock);
 462         dev_put(dev);
 463         return skb->len;
 464 }
 465
 466 void
 467 tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 468 {
 469 #ifdef CONFIG_NET_CLS_ACT
 470         if (exts->action) {
 471                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 472                 exts->action = NULL;
 473         }
 474 #elif defined CONFIG_NET_CLS_POLICE
 475         if (exts->police) {
 476                 tcf_police_release(exts->police, TCA_ACT_UNBIND);
 477                 exts->police = NULL;
 478         }
 479 #endif
 480 }
 481
 482
 483 int
 484 tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
 485                   struct rtattr *rate_tlv, struct tcf_exts *exts,
 486                   struct tcf_ext_map *map)
 487 {
 488         memset(exts, 0, sizeof(*exts));
 489
 490 #ifdef CONFIG_NET_CLS_ACT
 491         {
 492                 int err;
 493                 struct tc_action *act;
 494
 495                 if (map->police && tb[map->police-1]) {
 496                         act = tcf_action_init_1(tb[map->police-1], rate_tlv, "police",
 497                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 498                         if (act == NULL)
 499                                 return err;
 500
 501                         act->type = TCA_OLD_COMPAT;
 502                         exts->action = act;
 503                 } else if (map->action && tb[map->action-1]) {
 504                         act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
 505                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 506                         if (act == NULL)
 507                                 return err;
 508
 509                         exts->action = act;
 510                 }
 511         }
 512 #elif defined CONFIG_NET_CLS_POLICE
 513         if (map->police && tb[map->police-1]) {
 514                 struct tcf_police *p;
 515
 516                 p = tcf_police_locate(tb[map->police-1], rate_tlv);
 517                 if (p == NULL)
 518                         return -EINVAL;
 519
 520                 exts->police = p;
 521         } else if (map->action && tb[map->action-1])
 522                 return -EOPNOTSUPP;
 523 #else
 524         if ((map->action && tb[map->action-1]) ||
 525             (map->police && tb[map->police-1]))
 526                 return -EOPNOTSUPP;
 527 #endif
 528
 529         return 0;
 530 }
 531
 532 void
 533 tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 534                 struct tcf_exts *src)
 535 {
 536 #ifdef CONFIG_NET_CLS_ACT
 537         if (src->action) {
 538                 struct tc_action *act;
 539                 tcf_tree_lock(tp);
 540                 act = xchg(&dst->action, src->action);
 541                 tcf_tree_unlock(tp);
 542                 if (act)
 543                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 544         }
 545 #elif defined CONFIG_NET_CLS_POLICE
 546         if (src->police) {
 547                 struct tcf_police *p;
 548                 tcf_tree_lock(tp);
 549                 p = xchg(&dst->police, src->police);
 550                 tcf_tree_unlock(tp);
 551                 if (p)
 552                         tcf_police_release(p, TCA_ACT_UNBIND);
 553         }
 554 #endif
 555 }
 556
 557 int
 558 tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 559               struct tcf_ext_map *map)
 560 {
 561 #ifdef CONFIG_NET_CLS_ACT
 562         if (map->action && exts->action) {
 563                 /*
 564                  * again for backward compatible mode - we want
 565                  * to work with both old and new modes of entering
 566                  * tc data even if iproute2  was newer - jhs
 567                  */
 568                 struct rtattr * p_rta = (struct rtattr*) skb->tail;
 569
 570                 if (exts->action->type != TCA_OLD_COMPAT) {
 571                         RTA_PUT(skb, map->action, 0, NULL);
 572                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 573                                 goto rtattr_failure;
 574                         p_rta->rta_len = skb->tail - (u8*)p_rta;
 575                 } else if (map->police) {
 576                         RTA_PUT(skb, map->police, 0, NULL);
 577                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 578                                 goto rtattr_failure;
 579                         p_rta->rta_len = skb->tail - (u8*)p_rta;
 580                 }
 581         }
 582 #elif defined CONFIG_NET_CLS_POLICE
 583         if (map->police && exts->police) {
 584                 struct rtattr * p_rta = (struct rtattr*) skb->tail;
 585
 586                 RTA_PUT(skb, map->police, 0, NULL);
 587
 588                 if (tcf_police_dump(skb, exts->police) < 0)
 589                         goto rtattr_failure;
 590
 591                 p_rta->rta_len = skb->tail - (u8*)p_rta;
 592         }
 593 #endif
 594         return 0;
 595 rtattr_failure: __attribute__ ((unused))
 596         return -1;
 597 }
 598
 599 int
 600 tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 601                     struct tcf_ext_map *map)
 602 {
 603 #ifdef CONFIG_NET_CLS_ACT
 604         if (exts->action)
 605                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 606                         goto rtattr_failure;
 607 #elif defined CONFIG_NET_CLS_POLICE
 608         if (exts->police)
 609                 if (tcf_police_dump_stats(skb, exts->police) < 0)
 610                         goto rtattr_failure;
 611 #endif
 612         return 0;
 613 rtattr_failure: __attribute__ ((unused))
 614         return -1;
 615 }
 616
 617 static int __init tc_filter_init(void)
 618 {
 619         struct rtnetlink_link *link_p = rtnetlink_links[PF_UNSPEC];
 620
 621         /* Setup rtnetlink links. It is made here to avoid
 622            exporting large number of public symbols.
 623          */
 624
 625         if (link_p) {
 626                 link_p[RTM_NEWTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 627                 link_p[RTM_DELTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 628                 link_p[RTM_GETTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 629                 link_p[RTM_GETTFILTER-RTM_BASE].dumpit = tc_dump_tfilter;
 630         }
 631         return 0;
 632 }
 633
 634 subsys_initcall(tc_filter_init);
 635
 636 EXPORT_SYMBOL(register_tcf_proto_ops);
 637 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 638 EXPORT_SYMBOL(tcf_exts_validate);
 639 EXPORT_SYMBOL(tcf_exts_destroy);
 640 EXPORT_SYMBOL(tcf_exts_change);
 641 EXPORT_SYMBOL(tcf_exts_dump);
 642 EXPORT_SYMBOL(tcf_exts_dump_stats);