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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 <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/init.h>
  24 #include <linux/kmod.h>
  25 #include <linux/netlink.h>
  26 #include <net/netlink.h>
  27 #include <net/pkt_sched.h>
  28 #include <net/pkt_cls.h>
  29
  30 #if 0 /* control */
  31 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  32 #else
  33 #define DPRINTK(format,args...)
  34 #endif
  35
  36 /* The list of all installed classifier types */
  37
  38 static struct tcf_proto_ops *tcf_proto_base;
  39
  40 /* Protects list of registered TC modules. It is pure SMP lock. */
  41 static DEFINE_RWLOCK(cls_mod_lock);
  42
  43 /* Find classifier type by string name */
  44
  45 static struct tcf_proto_ops * tcf_proto_lookup_ops(struct rtattr *kind)
  46 {
  47         struct tcf_proto_ops *t = NULL;
  48
  49         if (kind) {
  50                 read_lock(&cls_mod_lock);
  51                 for (t = tcf_proto_base; t; t = t->next) {
  52                         if (rtattr_strcmp(kind, t->kind) == 0) {
  53                                 if (!try_module_get(t->owner))
  54                                         t = NULL;
  55                                 break;
  56                         }
  57                 }
  58                 read_unlock(&cls_mod_lock);
  59         }
  60         return t;
  61 }
  62
  63 /* Register(unregister) new classifier type */
  64
  65 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  66 {
  67         struct tcf_proto_ops *t, **tp;
  68         int rc = -EEXIST;
  69
  70         write_lock(&cls_mod_lock);
  71         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  72                 if (!strcmp(ops->kind, t->kind))
  73                         goto out;
  74
  75         ops->next = NULL;
  76         *tp = ops;
  77         rc = 0;
  78 out:
  79         write_unlock(&cls_mod_lock);
  80         return rc;
  81 }
  82
  83 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  84 {
  85         struct tcf_proto_ops *t, **tp;
  86         int rc = -ENOENT;
  87
  88         write_lock(&cls_mod_lock);
  89         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
  90                 if (t == ops)
  91                         break;
  92
  93         if (!t)
  94                 goto out;
  95         *tp = t->next;
  96         rc = 0;
  97 out:
  98         write_unlock(&cls_mod_lock);
  99         return rc;
 100 }
 101
 102 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 103                           struct tcf_proto *tp, unsigned long fh, int event);
 104
 105
 106 /* Select new prio value from the range, managed by kernel. */
 107
 108 static __inline__ u32 tcf_auto_prio(struct tcf_proto *tp)
 109 {
 110         u32 first = TC_H_MAKE(0xC0000000U,0U);
 111
 112         if (tp)
 113                 first = tp->prio-1;
 114
 115         return first;
 116 }
 117
 118 /* Add/change/delete/get a filter node */
 119
 120 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 121 {
 122         struct rtattr **tca;
 123         struct tcmsg *t;
 124         u32 protocol;
 125         u32 prio;
 126         u32 nprio;
 127         u32 parent;
 128         struct net_device *dev;
 129         struct Qdisc  *q;
 130         struct tcf_proto **back, **chain;
 131         struct tcf_proto *tp;
 132         struct tcf_proto_ops *tp_ops;
 133         const struct Qdisc_class_ops *cops;
 134         unsigned long cl;
 135         unsigned long fh;
 136         int err;
 137
 138 replay:
 139         tca = arg;
 140         t = NLMSG_DATA(n);
 141         protocol = TC_H_MIN(t->tcm_info);
 142         prio = TC_H_MAJ(t->tcm_info);
 143         nprio = prio;
 144         parent = t->tcm_parent;
 145         cl = 0;
 146
 147         if (prio == 0) {
 148                 /* If no priority is given, user wants we allocated it. */
 149                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 150                         return -ENOENT;
 151                 prio = TC_H_MAKE(0x80000000U,0U);
 152         }
 153
 154         /* Find head of filter chain. */
 155
 156         /* Find link */
 157         if ((dev = __dev_get_by_index(&init_net, t->tcm_ifindex)) == NULL)
 158                 return -ENODEV;
 159
 160         /* Find qdisc */
 161         if (!parent) {
 162                 q = dev->qdisc_sleeping;
 163                 parent = q->handle;
 164         } else if ((q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent))) == NULL)
 165                 return -EINVAL;
 166
 167         /* Is it classful? */
 168         if ((cops = q->ops->cl_ops) == NULL)
 169                 return -EINVAL;
 170
 171         /* Do we search for filter, attached to class? */
 172         if (TC_H_MIN(parent)) {
 173                 cl = cops->get(q, parent);
 174                 if (cl == 0)
 175                         return -ENOENT;
 176         }
 177
 178         /* And the last stroke */
 179         chain = cops->tcf_chain(q, cl);
 180         err = -EINVAL;
 181         if (chain == NULL)
 182                 goto errout;
 183
 184         /* Check the chain for existence of proto-tcf with this priority */
 185         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 186                 if (tp->prio >= prio) {
 187                         if (tp->prio == prio) {
 188                                 if (!nprio || (tp->protocol != protocol && protocol))
 189                                         goto errout;
 190                         } else
 191                                 tp = NULL;
 192                         break;
 193                 }
 194         }
 195
 196         if (tp == NULL) {
 197                 /* Proto-tcf does not exist, create new one */
 198
 199                 if (tca[TCA_KIND-1] == NULL || !protocol)
 200                         goto errout;
 201
 202                 err = -ENOENT;
 203                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 204                         goto errout;
 205
 206
 207                 /* Create new proto tcf */
 208
 209                 err = -ENOBUFS;
 210                 if ((tp = kzalloc(sizeof(*tp), GFP_KERNEL)) == NULL)
 211                         goto errout;
 212                 err = -EINVAL;
 213                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
 214                 if (tp_ops == NULL) {
 215 #ifdef CONFIG_KMOD
 216                         struct rtattr *kind = tca[TCA_KIND-1];
 217                         char name[IFNAMSIZ];
 218
 219                         if (kind != NULL &&
 220                             rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 221                                 rtnl_unlock();
 222                                 request_module("cls_%s", name);
 223                                 rtnl_lock();
 224                                 tp_ops = tcf_proto_lookup_ops(kind);
 225                                 /* We dropped the RTNL semaphore in order to
 226                                  * perform the module load.  So, even if we
 227                                  * succeeded in loading the module we have to
 228                                  * replay the request.  We indicate this using
 229                                  * -EAGAIN.
 230                                  */
 231                                 if (tp_ops != NULL) {
 232                                         module_put(tp_ops->owner);
 233                                         err = -EAGAIN;
 234                                 }
 235                         }
 236 #endif
 237                         kfree(tp);
 238                         goto errout;
 239                 }
 240                 tp->ops = tp_ops;
 241                 tp->protocol = protocol;
 242                 tp->prio = nprio ? : tcf_auto_prio(*back);
 243                 tp->q = q;
 244                 tp->classify = tp_ops->classify;
 245                 tp->classid = parent;
 246                 if ((err = tp_ops->init(tp)) != 0) {
 247                         module_put(tp_ops->owner);
 248                         kfree(tp);
 249                         goto errout;
 250                 }
 251
 252                 qdisc_lock_tree(dev);
 253                 tp->next = *back;
 254                 *back = tp;
 255                 qdisc_unlock_tree(dev);
 256
 257         } else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
 258                 goto errout;
 259
 260         fh = tp->ops->get(tp, t->tcm_handle);
 261
 262         if (fh == 0) {
 263                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 264                         qdisc_lock_tree(dev);
 265                         *back = tp->next;
 266                         qdisc_unlock_tree(dev);
 267
 268                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 269                         tcf_destroy(tp);
 270                         err = 0;
 271                         goto errout;
 272                 }
 273
 274                 err = -ENOENT;
 275                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 276                         goto errout;
 277         } else {
 278                 switch (n->nlmsg_type) {
 279                 case RTM_NEWTFILTER:
 280                         err = -EEXIST;
 281                         if (n->nlmsg_flags&NLM_F_EXCL)
 282                                 goto errout;
 283                         break;
 284                 case RTM_DELTFILTER:
 285                         err = tp->ops->delete(tp, fh);
 286                         if (err == 0)
 287                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 288                         goto errout;
 289                 case RTM_GETTFILTER:
 290                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 291                         goto errout;
 292                 default:
 293                         err = -EINVAL;
 294                         goto errout;
 295                 }
 296         }
 297
 298         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 299         if (err == 0)
 300                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 301
 302 errout:
 303         if (cl)
 304                 cops->put(q, cl);
 305         if (err == -EAGAIN)
 306                 /* Replay the request. */
 307                 goto replay;
 308         return err;
 309 }
 310
 311 static int
 312 tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, unsigned long fh,
 313               u32 pid, u32 seq, u16 flags, int event)
 314 {
 315         struct tcmsg *tcm;
 316         struct nlmsghdr  *nlh;
 317         unsigned char *b = skb_tail_pointer(skb);
 318
 319         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 320         tcm = NLMSG_DATA(nlh);
 321         tcm->tcm_family = AF_UNSPEC;
 322         tcm->tcm__pad1 = 0;
 323         tcm->tcm__pad1 = 0;
 324         tcm->tcm_ifindex = tp->q->dev->ifindex;
 325         tcm->tcm_parent = tp->classid;
 326         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 327         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
 328         tcm->tcm_handle = fh;
 329         if (RTM_DELTFILTER != event) {
 330                 tcm->tcm_handle = 0;
 331                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 332                         goto rtattr_failure;
 333         }
 334         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 335         return skb->len;
 336
 337 nlmsg_failure:
 338 rtattr_failure:
 339         nlmsg_trim(skb, b);
 340         return -1;
 341 }
 342
 343 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 344                           struct tcf_proto *tp, unsigned long fh, int event)
 345 {
 346         struct sk_buff *skb;
 347         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 348
 349         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 350         if (!skb)
 351                 return -ENOBUFS;
 352
 353         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 354                 kfree_skb(skb);
 355                 return -EINVAL;
 356         }
 357
 358         return rtnetlink_send(skb, pid, RTNLGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
 359 }
 360
 361 struct tcf_dump_args
 362 {
 363         struct tcf_walker w;
 364         struct sk_buff *skb;
 365         struct netlink_callback *cb;
 366 };
 367
 368 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, struct tcf_walker *arg)
 369 {
 370         struct tcf_dump_args *a = (void*)arg;
 371
 372         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 373                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 374 }
 375
 376 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 377 {
 378         int t;
 379         int s_t;
 380         struct net_device *dev;
 381         struct Qdisc *q;
 382         struct tcf_proto *tp, **chain;
 383         struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
 384         unsigned long cl = 0;
 385         const struct Qdisc_class_ops *cops;
 386         struct tcf_dump_args arg;
 387
 388         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 389                 return skb->len;
 390         if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 391                 return skb->len;
 392
 393         if (!tcm->tcm_parent)
 394                 q = dev->qdisc_sleeping;
 395         else
 396                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 397         if (!q)
 398                 goto out;
 399         if ((cops = q->ops->cl_ops) == NULL)
 400                 goto errout;
 401         if (TC_H_MIN(tcm->tcm_parent)) {
 402                 cl = cops->get(q, tcm->tcm_parent);
 403                 if (cl == 0)
 404                         goto errout;
 405         }
 406         chain = cops->tcf_chain(q, cl);
 407         if (chain == NULL)
 408                 goto errout;
 409
 410         s_t = cb->args[0];
 411
 412         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 413                 if (t < s_t) continue;
 414                 if (TC_H_MAJ(tcm->tcm_info) &&
 415                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 416                         continue;
 417                 if (TC_H_MIN(tcm->tcm_info) &&
 418                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 419                         continue;
 420                 if (t > s_t)
 421                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 422                 if (cb->args[1] == 0) {
 423                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 424                                           cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER) <= 0) {
 425                                 break;
 426                         }
 427                         cb->args[1] = 1;
 428                 }
 429                 if (tp->ops->walk == NULL)
 430                         continue;
 431                 arg.w.fn = tcf_node_dump;
 432                 arg.skb = skb;
 433                 arg.cb = cb;
 434                 arg.w.stop = 0;
 435                 arg.w.skip = cb->args[1]-1;
 436                 arg.w.count = 0;
 437                 tp->ops->walk(tp, &arg.w);
 438                 cb->args[1] = arg.w.count+1;
 439                 if (arg.w.stop)
 440                         break;
 441         }
 442
 443         cb->args[0] = t;
 444
 445 errout:
 446         if (cl)
 447                 cops->put(q, cl);
 448 out:
 449         dev_put(dev);
 450         return skb->len;
 451 }
 452
 453 void
 454 tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 455 {
 456 #ifdef CONFIG_NET_CLS_ACT
 457         if (exts->action) {
 458                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 459                 exts->action = NULL;
 460         }
 461 #endif
 462 }
 463
 464
 465 int
 466 tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
 467                   struct rtattr *rate_tlv, struct tcf_exts *exts,
 468                   struct tcf_ext_map *map)
 469 {
 470         memset(exts, 0, sizeof(*exts));
 471
 472 #ifdef CONFIG_NET_CLS_ACT
 473         {
 474                 int err;
 475                 struct tc_action *act;
 476
 477                 if (map->police && tb[map->police-1]) {
 478                         act = tcf_action_init_1(tb[map->police-1], rate_tlv, "police",
 479                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 480                         if (act == NULL)
 481                                 return err;
 482
 483                         act->type = TCA_OLD_COMPAT;
 484                         exts->action = act;
 485                 } else if (map->action && tb[map->action-1]) {
 486                         act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
 487                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 488                         if (act == NULL)
 489                                 return err;
 490
 491                         exts->action = act;
 492                 }
 493         }
 494 #else
 495         if ((map->action && tb[map->action-1]) ||
 496             (map->police && tb[map->police-1]))
 497                 return -EOPNOTSUPP;
 498 #endif
 499
 500         return 0;
 501 }
 502
 503 void
 504 tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 505                 struct tcf_exts *src)
 506 {
 507 #ifdef CONFIG_NET_CLS_ACT
 508         if (src->action) {
 509                 struct tc_action *act;
 510                 tcf_tree_lock(tp);
 511                 act = xchg(&dst->action, src->action);
 512                 tcf_tree_unlock(tp);
 513                 if (act)
 514                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 515         }
 516 #endif
 517 }
 518
 519 int
 520 tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 521               struct tcf_ext_map *map)
 522 {
 523 #ifdef CONFIG_NET_CLS_ACT
 524         if (map->action && exts->action) {
 525                 /*
 526                  * again for backward compatible mode - we want
 527                  * to work with both old and new modes of entering
 528                  * tc data even if iproute2  was newer - jhs
 529                  */
 530                 struct rtattr *p_rta = (struct rtattr *)skb_tail_pointer(skb);
 531
 532                 if (exts->action->type != TCA_OLD_COMPAT) {
 533                         RTA_PUT(skb, map->action, 0, NULL);
 534                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 535                                 goto rtattr_failure;
 536                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
 537                 } else if (map->police) {
 538                         RTA_PUT(skb, map->police, 0, NULL);
 539                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 540                                 goto rtattr_failure;
 541                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
 542                 }
 543         }
 544 #endif
 545         return 0;
 546 rtattr_failure: __attribute__ ((unused))
 547         return -1;
 548 }
 549
 550 int
 551 tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 552                     struct tcf_ext_map *map)
 553 {
 554 #ifdef CONFIG_NET_CLS_ACT
 555         if (exts->action)
 556                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 557                         goto rtattr_failure;
 558 #endif
 559         return 0;
 560 rtattr_failure: __attribute__ ((unused))
 561         return -1;
 562 }
 563
 564 static int __init tc_filter_init(void)
 565 {
 566         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 567         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 568         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 569                                                  tc_dump_tfilter);
 570
 571         return 0;
 572 }
 573
 574 subsys_initcall(tc_filter_init);
 575
 576 EXPORT_SYMBOL(register_tcf_proto_ops);
 577 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 578 EXPORT_SYMBOL(tcf_exts_validate);
 579 EXPORT_SYMBOL(tcf_exts_destroy);
 580 EXPORT_SYMBOL(tcf_exts_change);
 581 EXPORT_SYMBOL(tcf_exts_dump);
 582 EXPORT_SYMBOL(tcf_exts_dump_stats);