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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         int tp_created = 0;
 139
 140         if (!net_eq(net, &init_net))
 141                 return -EINVAL;
 142
 143 replay:
 144         t = NLMSG_DATA(n);
 145         protocol = TC_H_MIN(t->tcm_info);
 146         prio = TC_H_MAJ(t->tcm_info);
 147         nprio = prio;
 148         parent = t->tcm_parent;
 149         cl = 0;
 150
 151         if (prio == 0) {
 152                 /* If no priority is given, user wants we allocated it. */
 153                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 154                         return -ENOENT;
 155                 prio = TC_H_MAKE(0x80000000U, 0U);
 156         }
 157
 158         /* Find head of filter chain. */
 159
 160         /* Find link */
 161         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
 162         if (dev == NULL)
 163                 return -ENODEV;
 164
 165         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 166         if (err < 0)
 167                 return err;
 168
 169         /* Find qdisc */
 170         if (!parent) {
 171                 q = dev->qdisc;
 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         if (cops->tcf_chain == NULL)
 184                 return -EOPNOTSUPP;
 185
 186         /* Do we search for filter, attached to class? */
 187         if (TC_H_MIN(parent)) {
 188                 cl = cops->get(q, parent);
 189                 if (cl == 0)
 190                         return -ENOENT;
 191         }
 192
 193         /* And the last stroke */
 194         chain = cops->tcf_chain(q, cl);
 195         err = -EINVAL;
 196         if (chain == NULL)
 197                 goto errout;
 198
 199         /* Check the chain for existence of proto-tcf with this priority */
 200         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 201                 if (tp->prio >= prio) {
 202                         if (tp->prio == prio) {
 203                                 if (!nprio || (tp->protocol != protocol && protocol))
 204                                         goto errout;
 205                         } else
 206                                 tp = NULL;
 207                         break;
 208                 }
 209         }
 210
 211         root_lock = qdisc_root_sleeping_lock(q);
 212
 213         if (tp == NULL) {
 214                 /* Proto-tcf does not exist, create new one */
 215
 216                 if (tca[TCA_KIND] == NULL || !protocol)
 217                         goto errout;
 218
 219                 err = -ENOENT;
 220                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 221                         goto errout;
 222
 223
 224                 /* Create new proto tcf */
 225
 226                 err = -ENOBUFS;
 227                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 228                 if (tp == NULL)
 229                         goto errout;
 230                 err = -ENOENT;
 231                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 232                 if (tp_ops == NULL) {
 233 #ifdef CONFIG_MODULES
 234                         struct nlattr *kind = tca[TCA_KIND];
 235                         char name[IFNAMSIZ];
 236
 237                         if (kind != NULL &&
 238                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 239                                 rtnl_unlock();
 240                                 request_module("cls_%s", name);
 241                                 rtnl_lock();
 242                                 tp_ops = tcf_proto_lookup_ops(kind);
 243                                 /* We dropped the RTNL semaphore in order to
 244                                  * perform the module load.  So, even if we
 245                                  * succeeded in loading the module we have to
 246                                  * replay the request.  We indicate this using
 247                                  * -EAGAIN.
 248                                  */
 249                                 if (tp_ops != NULL) {
 250                                         module_put(tp_ops->owner);
 251                                         err = -EAGAIN;
 252                                 }
 253                         }
 254 #endif
 255                         kfree(tp);
 256                         goto errout;
 257                 }
 258                 tp->ops = tp_ops;
 259                 tp->protocol = protocol;
 260                 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
 261                 tp->q = q;
 262                 tp->classify = tp_ops->classify;
 263                 tp->classid = parent;
 264
 265                 err = tp_ops->init(tp);
 266                 if (err != 0) {
 267                         module_put(tp_ops->owner);
 268                         kfree(tp);
 269                         goto errout;
 270                 }
 271
 272                 tp_created = 1;
 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                                 if (tp_created)
 301                                         tcf_destroy(tp);
 302                                 goto errout;
 303                         }
 304                         break;
 305                 case RTM_DELTFILTER:
 306                         err = tp->ops->delete(tp, fh);
 307                         if (err == 0)
 308                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 309                         goto errout;
 310                 case RTM_GETTFILTER:
 311                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 312                         goto errout;
 313                 default:
 314                         err = -EINVAL;
 315                         goto errout;
 316                 }
 317         }
 318
 319         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 320         if (err == 0) {
 321                 if (tp_created) {
 322                         spin_lock_bh(root_lock);
 323                         tp->next = *back;
 324                         *back = tp;
 325                         spin_unlock_bh(root_lock);
 326                 }
 327                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 328         } else {
 329                 if (tp_created)
 330                         tcf_destroy(tp);
 331         }
 332
 333 errout:
 334         if (cl)
 335                 cops->put(q, cl);
 336         if (err == -EAGAIN)
 337                 /* Replay the request. */
 338                 goto replay;
 339         return err;
 340 }
 341
 342 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 343                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
 344 {
 345         struct tcmsg *tcm;
 346         struct nlmsghdr  *nlh;
 347         unsigned char *b = skb_tail_pointer(skb);
 348
 349         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 350         tcm = NLMSG_DATA(nlh);
 351         tcm->tcm_family = AF_UNSPEC;
 352         tcm->tcm__pad1 = 0;
 353         tcm->tcm__pad2 = 0;
 354         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 355         tcm->tcm_parent = tp->classid;
 356         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 357         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
 358         tcm->tcm_handle = fh;
 359         if (RTM_DELTFILTER != event) {
 360                 tcm->tcm_handle = 0;
 361                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 362                         goto nla_put_failure;
 363         }
 364         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 365         return skb->len;
 366
 367 nlmsg_failure:
 368 nla_put_failure:
 369         nlmsg_trim(skb, b);
 370         return -1;
 371 }
 372
 373 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 374                           struct tcf_proto *tp, unsigned long fh, int event)
 375 {
 376         struct sk_buff *skb;
 377         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 378
 379         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 380         if (!skb)
 381                 return -ENOBUFS;
 382
 383         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 384                 kfree_skb(skb);
 385                 return -EINVAL;
 386         }
 387
 388         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
 389                               n->nlmsg_flags & NLM_F_ECHO);
 390 }
 391
 392 struct tcf_dump_args {
 393         struct tcf_walker w;
 394         struct sk_buff *skb;
 395         struct netlink_callback *cb;
 396 };
 397
 398 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 399                          struct tcf_walker *arg)
 400 {
 401         struct tcf_dump_args *a = (void *)arg;
 402
 403         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 404                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 405 }
 406
 407 /* called with RTNL */
 408 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 409 {
 410         struct net *net = sock_net(skb->sk);
 411         int t;
 412         int s_t;
 413         struct net_device *dev;
 414         struct Qdisc *q;
 415         struct tcf_proto *tp, **chain;
 416         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
 417         unsigned long cl = 0;
 418         const struct Qdisc_class_ops *cops;
 419         struct tcf_dump_args arg;
 420
 421         if (!net_eq(net, &init_net))
 422                 return 0;
 423
 424         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 425                 return skb->len;
 426         if ((dev = __dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 427                 return skb->len;
 428
 429         if (!tcm->tcm_parent)
 430                 q = dev->qdisc;
 431         else
 432                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 433         if (!q)
 434                 goto out;
 435         if ((cops = q->ops->cl_ops) == NULL)
 436                 goto errout;
 437         if (cops->tcf_chain == NULL)
 438                 goto errout;
 439         if (TC_H_MIN(tcm->tcm_parent)) {
 440                 cl = cops->get(q, tcm->tcm_parent);
 441                 if (cl == 0)
 442                         goto errout;
 443         }
 444         chain = cops->tcf_chain(q, cl);
 445         if (chain == NULL)
 446                 goto errout;
 447
 448         s_t = cb->args[0];
 449
 450         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 451                 if (t < s_t) continue;
 452                 if (TC_H_MAJ(tcm->tcm_info) &&
 453                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 454                         continue;
 455                 if (TC_H_MIN(tcm->tcm_info) &&
 456                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 457                         continue;
 458                 if (t > s_t)
 459                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 460                 if (cb->args[1] == 0) {
 461                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 462                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 463                                           RTM_NEWTFILTER) <= 0)
 464                                 break;
 465
 466                         cb->args[1] = 1;
 467                 }
 468                 if (tp->ops->walk == NULL)
 469                         continue;
 470                 arg.w.fn = tcf_node_dump;
 471                 arg.skb = skb;
 472                 arg.cb = cb;
 473                 arg.w.stop = 0;
 474                 arg.w.skip = cb->args[1]-1;
 475                 arg.w.count = 0;
 476                 tp->ops->walk(tp, &arg.w);
 477                 cb->args[1] = arg.w.count+1;
 478                 if (arg.w.stop)
 479                         break;
 480         }
 481
 482         cb->args[0] = t;
 483
 484 errout:
 485         if (cl)
 486                 cops->put(q, cl);
 487 out:
 488         return skb->len;
 489 }
 490
 491 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 492 {
 493 #ifdef CONFIG_NET_CLS_ACT
 494         if (exts->action) {
 495                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 496                 exts->action = NULL;
 497         }
 498 #endif
 499 }
 500 EXPORT_SYMBOL(tcf_exts_destroy);
 501
 502 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
 503                   struct nlattr *rate_tlv, struct tcf_exts *exts,
 504                   const struct tcf_ext_map *map)
 505 {
 506         memset(exts, 0, sizeof(*exts));
 507
 508 #ifdef CONFIG_NET_CLS_ACT
 509         {
 510                 struct tc_action *act;
 511
 512                 if (map->police && tb[map->police]) {
 513                         act = tcf_action_init_1(tb[map->police], rate_tlv,
 514                                                 "police", TCA_ACT_NOREPLACE,
 515                                                 TCA_ACT_BIND);
 516                         if (IS_ERR(act))
 517                                 return PTR_ERR(act);
 518
 519                         act->type = TCA_OLD_COMPAT;
 520                         exts->action = act;
 521                 } else if (map->action && tb[map->action]) {
 522                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 523                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 524                         if (IS_ERR(act))
 525                                 return PTR_ERR(act);
 526
 527                         exts->action = act;
 528                 }
 529         }
 530 #else
 531         if ((map->action && tb[map->action]) ||
 532             (map->police && tb[map->police]))
 533                 return -EOPNOTSUPP;
 534 #endif
 535
 536         return 0;
 537 }
 538 EXPORT_SYMBOL(tcf_exts_validate);
 539
 540 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 541                      struct tcf_exts *src)
 542 {
 543 #ifdef CONFIG_NET_CLS_ACT
 544         if (src->action) {
 545                 struct tc_action *act;
 546                 tcf_tree_lock(tp);
 547                 act = dst->action;
 548                 dst->action = src->action;
 549                 tcf_tree_unlock(tp);
 550                 if (act)
 551                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 552         }
 553 #endif
 554 }
 555 EXPORT_SYMBOL(tcf_exts_change);
 556
 557 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 558                   const struct tcf_ext_map *map)
 559 {
 560 #ifdef CONFIG_NET_CLS_ACT
 561         if (map->action && exts->action) {
 562                 /*
 563                  * again for backward compatible mode - we want
 564                  * to work with both old and new modes of entering
 565                  * tc data even if iproute2  was newer - jhs
 566                  */
 567                 struct nlattr *nest;
 568
 569                 if (exts->action->type != TCA_OLD_COMPAT) {
 570                         nest = nla_nest_start(skb, map->action);
 571                         if (nest == NULL)
 572                                 goto nla_put_failure;
 573                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 574                                 goto nla_put_failure;
 575                         nla_nest_end(skb, nest);
 576                 } else if (map->police) {
 577                         nest = nla_nest_start(skb, map->police);
 578                         if (nest == NULL)
 579                                 goto nla_put_failure;
 580                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 581                                 goto nla_put_failure;
 582                         nla_nest_end(skb, nest);
 583                 }
 584         }
 585 #endif
 586         return 0;
 587 nla_put_failure: __attribute__ ((unused))
 588         return -1;
 589 }
 590 EXPORT_SYMBOL(tcf_exts_dump);
 591
 592
 593 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 594                         const struct tcf_ext_map *map)
 595 {
 596 #ifdef CONFIG_NET_CLS_ACT
 597         if (exts->action)
 598                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 599                         goto nla_put_failure;
 600 #endif
 601         return 0;
 602 nla_put_failure: __attribute__ ((unused))
 603         return -1;
 604 }
 605 EXPORT_SYMBOL(tcf_exts_dump_stats);
 606
 607 static int __init tc_filter_init(void)
 608 {
 609         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 610         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 611         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 612                                                  tc_dump_tfilter);
 613
 614         return 0;
 615 }
 616
 617 subsys_initcall(tc_filter_init);