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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 <linux/err.h>
  27 #include <net/net_namespace.h>
  28 #include <net/sock.h>
  29 #include <net/netlink.h>
  30 #include <net/pkt_sched.h>
  31 #include <net/pkt_cls.h>
  32
  33 /* The list of all installed classifier types */
  34
  35 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
  36
  37 /* Protects list of registered TC modules. It is pure SMP lock. */
  38 static DEFINE_RWLOCK(cls_mod_lock);
  39
  40 /* Find classifier type by string name */
  41
  42 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
  43 {
  44         struct tcf_proto_ops *t = NULL;
  45
  46         if (kind) {
  47                 read_lock(&cls_mod_lock);
  48                 for (t = tcf_proto_base; t; t = t->next) {
  49                         if (nla_strcmp(kind, t->kind) == 0) {
  50                                 if (!try_module_get(t->owner))
  51                                         t = NULL;
  52                                 break;
  53                         }
  54                 }
  55                 read_unlock(&cls_mod_lock);
  56         }
  57         return t;
  58 }
  59
  60 /* Register(unregister) new classifier type */
  61
  62 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  63 {
  64         struct tcf_proto_ops *t, **tp;
  65         int rc = -EEXIST;
  66
  67         write_lock(&cls_mod_lock);
  68         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  69                 if (!strcmp(ops->kind, t->kind))
  70                         goto out;
  71
  72         ops->next = NULL;
  73         *tp = ops;
  74         rc = 0;
  75 out:
  76         write_unlock(&cls_mod_lock);
  77         return rc;
  78 }
  79 EXPORT_SYMBOL(register_tcf_proto_ops);
  80
  81 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  82 {
  83         struct tcf_proto_ops *t, **tp;
  84         int rc = -ENOENT;
  85
  86         write_lock(&cls_mod_lock);
  87         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
  88                 if (t == ops)
  89                         break;
  90
  91         if (!t)
  92                 goto out;
  93         *tp = t->next;
  94         rc = 0;
  95 out:
  96         write_unlock(&cls_mod_lock);
  97         return rc;
  98 }
  99 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 100
 101 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 102                           struct tcf_proto *tp, unsigned long fh, int event);
 103
 104
 105 /* Select new prio value from the range, managed by kernel. */
 106
 107 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 108 {
 109         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 110
 111         if (tp)
 112                 first = tp->prio-1;
 113
 114         return first;
 115 }
 116
 117 /* Add/change/delete/get a filter node */
 118
 119 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 120 {
 121         struct net *net = sock_net(skb->sk);
 122         struct nlattr *tca[TCA_MAX + 1];
 123         spinlock_t *root_lock;
 124         struct tcmsg *t;
 125         u32 protocol;
 126         u32 prio;
 127         u32 nprio;
 128         u32 parent;
 129         struct net_device *dev;
 130         struct Qdisc  *q;
 131         struct tcf_proto **back, **chain;
 132         struct tcf_proto *tp;
 133         struct tcf_proto_ops *tp_ops;
 134         const struct Qdisc_class_ops *cops;
 135         unsigned long cl;
 136         unsigned long fh;
 137         int err;
 138
 139         if (net != &init_net)
 140                 return -EINVAL;
 141
 142 replay:
 143         t = NLMSG_DATA(n);
 144         protocol = TC_H_MIN(t->tcm_info);
 145         prio = TC_H_MAJ(t->tcm_info);
 146         nprio = prio;
 147         parent = t->tcm_parent;
 148         cl = 0;
 149
 150         if (prio == 0) {
 151                 /* If no priority is given, user wants we allocated it. */
 152                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 153                         return -ENOENT;
 154                 prio = TC_H_MAKE(0x80000000U, 0U);
 155         }
 156
 157         /* Find head of filter chain. */
 158
 159         /* Find link */
 160         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
 161         if (dev == NULL)
 162                 return -ENODEV;
 163
 164         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 165         if (err < 0)
 166                 return err;
 167
 168         /* Find qdisc */
 169         if (!parent) {
 170                 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
 171                 q = dev_queue->qdisc_sleeping;
 172                 parent = q->handle;
 173         } else {
 174                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 175                 if (q == NULL)
 176                         return -EINVAL;
 177         }
 178
 179         /* Is it classful? */
 180         if ((cops = q->ops->cl_ops) == NULL)
 181                 return -EINVAL;
 182
 183         /* Do we search for filter, attached to class? */
 184         if (TC_H_MIN(parent)) {
 185                 cl = cops->get(q, parent);
 186                 if (cl == 0)
 187                         return -ENOENT;
 188         }
 189
 190         /* And the last stroke */
 191         chain = cops->tcf_chain(q, cl);
 192         err = -EINVAL;
 193         if (chain == NULL)
 194                 goto errout;
 195
 196         /* Check the chain for existence of proto-tcf with this priority */
 197         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 198                 if (tp->prio >= prio) {
 199                         if (tp->prio == prio) {
 200                                 if (!nprio || (tp->protocol != protocol && protocol))
 201                                         goto errout;
 202                         } else
 203                                 tp = NULL;
 204                         break;
 205                 }
 206         }
 207
 208         root_lock = qdisc_root_sleeping_lock(q);
 209
 210         if (tp == NULL) {
 211                 /* Proto-tcf does not exist, create new one */
 212
 213                 if (tca[TCA_KIND] == NULL || !protocol)
 214                         goto errout;
 215
 216                 err = -ENOENT;
 217                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 218                         goto errout;
 219
 220
 221                 /* Create new proto tcf */
 222
 223                 err = -ENOBUFS;
 224                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 225                 if (tp == NULL)
 226                         goto errout;
 227                 err = -ENOENT;
 228                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 229                 if (tp_ops == NULL) {
 230 #ifdef CONFIG_MODULES
 231                         struct nlattr *kind = tca[TCA_KIND];
 232                         char name[IFNAMSIZ];
 233
 234                         if (kind != NULL &&
 235                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 236                                 rtnl_unlock();
 237                                 request_module("cls_%s", name);
 238                                 rtnl_lock();
 239                                 tp_ops = tcf_proto_lookup_ops(kind);
 240                                 /* We dropped the RTNL semaphore in order to
 241                                  * perform the module load.  So, even if we
 242                                  * succeeded in loading the module we have to
 243                                  * replay the request.  We indicate this using
 244                                  * -EAGAIN.
 245                                  */
 246                                 if (tp_ops != NULL) {
 247                                         module_put(tp_ops->owner);
 248                                         err = -EAGAIN;
 249                                 }
 250                         }
 251 #endif
 252                         kfree(tp);
 253                         goto errout;
 254                 }
 255                 tp->ops = tp_ops;
 256                 tp->protocol = protocol;
 257                 tp->prio = nprio ? : tcf_auto_prio(*back);
 258                 tp->q = q;
 259                 tp->classify = tp_ops->classify;
 260                 tp->classid = parent;
 261
 262                 err = tp_ops->init(tp);
 263                 if (err != 0) {
 264                         module_put(tp_ops->owner);
 265                         kfree(tp);
 266                         goto errout;
 267                 }
 268
 269                 spin_lock_bh(root_lock);
 270                 tp->next = *back;
 271                 *back = tp;
 272                 spin_unlock_bh(root_lock);
 273
 274         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 275                 goto errout;
 276
 277         fh = tp->ops->get(tp, t->tcm_handle);
 278
 279         if (fh == 0) {
 280                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 281                         spin_lock_bh(root_lock);
 282                         *back = tp->next;
 283                         spin_unlock_bh(root_lock);
 284
 285                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 286                         tcf_destroy(tp);
 287                         err = 0;
 288                         goto errout;
 289                 }
 290
 291                 err = -ENOENT;
 292                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 293                     !(n->nlmsg_flags & NLM_F_CREATE))
 294                         goto errout;
 295         } else {
 296                 switch (n->nlmsg_type) {
 297                 case RTM_NEWTFILTER:
 298                         err = -EEXIST;
 299                         if (n->nlmsg_flags & NLM_F_EXCL)
 300                                 goto errout;
 301                         break;
 302                 case RTM_DELTFILTER:
 303                         err = tp->ops->delete(tp, fh);
 304                         if (err == 0)
 305                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 306                         goto errout;
 307                 case RTM_GETTFILTER:
 308                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 309                         goto errout;
 310                 default:
 311                         err = -EINVAL;
 312                         goto errout;
 313                 }
 314         }
 315
 316         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 317         if (err == 0)
 318                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 319
 320 errout:
 321         if (cl)
 322                 cops->put(q, cl);
 323         if (err == -EAGAIN)
 324                 /* Replay the request. */
 325                 goto replay;
 326         return err;
 327 }
 328
 329 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 330                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
 331 {
 332         struct tcmsg *tcm;
 333         struct nlmsghdr  *nlh;
 334         unsigned char *b = skb_tail_pointer(skb);
 335
 336         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 337         tcm = NLMSG_DATA(nlh);
 338         tcm->tcm_family = AF_UNSPEC;
 339         tcm->tcm__pad1 = 0;
 340         tcm->tcm__pad1 = 0;
 341         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 342         tcm->tcm_parent = tp->classid;
 343         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 344         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
 345         tcm->tcm_handle = fh;
 346         if (RTM_DELTFILTER != event) {
 347                 tcm->tcm_handle = 0;
 348                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 349                         goto nla_put_failure;
 350         }
 351         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 352         return skb->len;
 353
 354 nlmsg_failure:
 355 nla_put_failure:
 356         nlmsg_trim(skb, b);
 357         return -1;
 358 }
 359
 360 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 361                           struct tcf_proto *tp, unsigned long fh, int event)
 362 {
 363         struct sk_buff *skb;
 364         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 365
 366         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 367         if (!skb)
 368                 return -ENOBUFS;
 369
 370         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 371                 kfree_skb(skb);
 372                 return -EINVAL;
 373         }
 374
 375         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
 376                               n->nlmsg_flags & NLM_F_ECHO);
 377 }
 378
 379 struct tcf_dump_args {
 380         struct tcf_walker w;
 381         struct sk_buff *skb;
 382         struct netlink_callback *cb;
 383 };
 384
 385 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 386                          struct tcf_walker *arg)
 387 {
 388         struct tcf_dump_args *a = (void *)arg;
 389
 390         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 391                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 392 }
 393
 394 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 395 {
 396         struct net *net = sock_net(skb->sk);
 397         struct netdev_queue *dev_queue;
 398         int t;
 399         int s_t;
 400         struct net_device *dev;
 401         struct Qdisc *q;
 402         struct tcf_proto *tp, **chain;
 403         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
 404         unsigned long cl = 0;
 405         const struct Qdisc_class_ops *cops;
 406         struct tcf_dump_args arg;
 407
 408         if (net != &init_net)
 409                 return 0;
 410
 411         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 412                 return skb->len;
 413         if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 414                 return skb->len;
 415
 416         dev_queue = netdev_get_tx_queue(dev, 0);
 417         if (!tcm->tcm_parent)
 418                 q = dev_queue->qdisc_sleeping;
 419         else
 420                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 421         if (!q)
 422                 goto out;
 423         if ((cops = q->ops->cl_ops) == NULL)
 424                 goto errout;
 425         if (TC_H_MIN(tcm->tcm_parent)) {
 426                 cl = cops->get(q, tcm->tcm_parent);
 427                 if (cl == 0)
 428                         goto errout;
 429         }
 430         chain = cops->tcf_chain(q, cl);
 431         if (chain == NULL)
 432                 goto errout;
 433
 434         s_t = cb->args[0];
 435
 436         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 437                 if (t < s_t) continue;
 438                 if (TC_H_MAJ(tcm->tcm_info) &&
 439                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 440                         continue;
 441                 if (TC_H_MIN(tcm->tcm_info) &&
 442                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 443                         continue;
 444                 if (t > s_t)
 445                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 446                 if (cb->args[1] == 0) {
 447                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 448                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 449                                           RTM_NEWTFILTER) <= 0)
 450                                 break;
 451
 452                         cb->args[1] = 1;
 453                 }
 454                 if (tp->ops->walk == NULL)
 455                         continue;
 456                 arg.w.fn = tcf_node_dump;
 457                 arg.skb = skb;
 458                 arg.cb = cb;
 459                 arg.w.stop = 0;
 460                 arg.w.skip = cb->args[1]-1;
 461                 arg.w.count = 0;
 462                 tp->ops->walk(tp, &arg.w);
 463                 cb->args[1] = arg.w.count+1;
 464                 if (arg.w.stop)
 465                         break;
 466         }
 467
 468         cb->args[0] = t;
 469
 470 errout:
 471         if (cl)
 472                 cops->put(q, cl);
 473 out:
 474         dev_put(dev);
 475         return skb->len;
 476 }
 477
 478 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 479 {
 480 #ifdef CONFIG_NET_CLS_ACT
 481         if (exts->action) {
 482                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 483                 exts->action = NULL;
 484         }
 485 #endif
 486 }
 487 EXPORT_SYMBOL(tcf_exts_destroy);
 488
 489 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
 490                   struct nlattr *rate_tlv, struct tcf_exts *exts,
 491                   const struct tcf_ext_map *map)
 492 {
 493         memset(exts, 0, sizeof(*exts));
 494
 495 #ifdef CONFIG_NET_CLS_ACT
 496         {
 497                 struct tc_action *act;
 498
 499                 if (map->police && tb[map->police]) {
 500                         act = tcf_action_init_1(tb[map->police], rate_tlv,
 501                                                 "police", TCA_ACT_NOREPLACE,
 502                                                 TCA_ACT_BIND);
 503                         if (IS_ERR(act))
 504                                 return PTR_ERR(act);
 505
 506                         act->type = TCA_OLD_COMPAT;
 507                         exts->action = act;
 508                 } else if (map->action && tb[map->action]) {
 509                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 510                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 511                         if (IS_ERR(act))
 512                                 return PTR_ERR(act);
 513
 514                         exts->action = act;
 515                 }
 516         }
 517 #else
 518         if ((map->action && tb[map->action]) ||
 519             (map->police && tb[map->police]))
 520                 return -EOPNOTSUPP;
 521 #endif
 522
 523         return 0;
 524 }
 525 EXPORT_SYMBOL(tcf_exts_validate);
 526
 527 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 528                      struct tcf_exts *src)
 529 {
 530 #ifdef CONFIG_NET_CLS_ACT
 531         if (src->action) {
 532                 struct tc_action *act;
 533                 tcf_tree_lock(tp);
 534                 act = dst->action;
 535                 dst->action = src->action;
 536                 tcf_tree_unlock(tp);
 537                 if (act)
 538                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 539         }
 540 #endif
 541 }
 542 EXPORT_SYMBOL(tcf_exts_change);
 543
 544 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 545                   const struct tcf_ext_map *map)
 546 {
 547 #ifdef CONFIG_NET_CLS_ACT
 548         if (map->action && exts->action) {
 549                 /*
 550                  * again for backward compatible mode - we want
 551                  * to work with both old and new modes of entering
 552                  * tc data even if iproute2  was newer - jhs
 553                  */
 554                 struct nlattr *nest;
 555
 556                 if (exts->action->type != TCA_OLD_COMPAT) {
 557                         nest = nla_nest_start(skb, map->action);
 558                         if (nest == NULL)
 559                                 goto nla_put_failure;
 560                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 561                                 goto nla_put_failure;
 562                         nla_nest_end(skb, nest);
 563                 } else if (map->police) {
 564                         nest = nla_nest_start(skb, map->police);
 565                         if (nest == NULL)
 566                                 goto nla_put_failure;
 567                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 568                                 goto nla_put_failure;
 569                         nla_nest_end(skb, nest);
 570                 }
 571         }
 572 #endif
 573         return 0;
 574 nla_put_failure: __attribute__ ((unused))
 575         return -1;
 576 }
 577 EXPORT_SYMBOL(tcf_exts_dump);
 578
 579
 580 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 581                         const struct tcf_ext_map *map)
 582 {
 583 #ifdef CONFIG_NET_CLS_ACT
 584         if (exts->action)
 585                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 586                         goto nla_put_failure;
 587 #endif
 588         return 0;
 589 nla_put_failure: __attribute__ ((unused))
 590         return -1;
 591 }
 592 EXPORT_SYMBOL(tcf_exts_dump_stats);
 593
 594 static int __init tc_filter_init(void)
 595 {
 596         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 597         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 598         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 599                                                  tc_dump_tfilter);
 600
 601         return 0;
 602 }
 603
 604 subsys_initcall(tc_filter_init);