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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/net_namespace.h>
  27 #include <net/sock.h>
  28 #include <net/netlink.h>
  29 #include <net/pkt_sched.h>
  30 #include <net/pkt_cls.h>
  31
  32 #if 0 /* control */
  33 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  34 #else
  35 #define DPRINTK(format,args...)
  36 #endif
  37
  38 /* The list of all installed classifier types */
  39
  40 static struct tcf_proto_ops *tcf_proto_base;
  41
  42 /* Protects list of registered TC modules. It is pure SMP lock. */
  43 static DEFINE_RWLOCK(cls_mod_lock);
  44
  45 /* Find classifier type by string name */
  46
  47 static struct tcf_proto_ops * tcf_proto_lookup_ops(struct rtattr *kind)
  48 {
  49         struct tcf_proto_ops *t = NULL;
  50
  51         if (kind) {
  52                 read_lock(&cls_mod_lock);
  53                 for (t = tcf_proto_base; t; t = t->next) {
  54                         if (rtattr_strcmp(kind, t->kind) == 0) {
  55                                 if (!try_module_get(t->owner))
  56                                         t = NULL;
  57                                 break;
  58                         }
  59                 }
  60                 read_unlock(&cls_mod_lock);
  61         }
  62         return t;
  63 }
  64
  65 /* Register(unregister) new classifier type */
  66
  67 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  68 {
  69         struct tcf_proto_ops *t, **tp;
  70         int rc = -EEXIST;
  71
  72         write_lock(&cls_mod_lock);
  73         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  74                 if (!strcmp(ops->kind, t->kind))
  75                         goto out;
  76
  77         ops->next = NULL;
  78         *tp = ops;
  79         rc = 0;
  80 out:
  81         write_unlock(&cls_mod_lock);
  82         return rc;
  83 }
  84
  85 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  86 {
  87         struct tcf_proto_ops *t, **tp;
  88         int rc = -ENOENT;
  89
  90         write_lock(&cls_mod_lock);
  91         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
  92                 if (t == ops)
  93                         break;
  94
  95         if (!t)
  96                 goto out;
  97         *tp = t->next;
  98         rc = 0;
  99 out:
 100         write_unlock(&cls_mod_lock);
 101         return rc;
 102 }
 103
 104 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 105                           struct tcf_proto *tp, unsigned long fh, int event);
 106
 107
 108 /* Select new prio value from the range, managed by kernel. */
 109
 110 static __inline__ u32 tcf_auto_prio(struct tcf_proto *tp)
 111 {
 112         u32 first = TC_H_MAKE(0xC0000000U,0U);
 113
 114         if (tp)
 115                 first = tp->prio-1;
 116
 117         return first;
 118 }
 119
 120 /* Add/change/delete/get a filter node */
 121
 122 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 123 {
 124         struct net *net = skb->sk->sk_net;
 125         struct rtattr **tca;
 126         struct tcmsg *t;
 127         u32 protocol;
 128         u32 prio;
 129         u32 nprio;
 130         u32 parent;
 131         struct net_device *dev;
 132         struct Qdisc  *q;
 133         struct tcf_proto **back, **chain;
 134         struct tcf_proto *tp;
 135         struct tcf_proto_ops *tp_ops;
 136         const struct Qdisc_class_ops *cops;
 137         unsigned long cl;
 138         unsigned long fh;
 139         int err;
 140
 141         if (net != &init_net)
 142                 return -EINVAL;
 143
 144 replay:
 145         tca = arg;
 146         t = NLMSG_DATA(n);
 147         protocol = TC_H_MIN(t->tcm_info);
 148         prio = TC_H_MAJ(t->tcm_info);
 149         nprio = prio;
 150         parent = t->tcm_parent;
 151         cl = 0;
 152
 153         if (prio == 0) {
 154                 /* If no priority is given, user wants we allocated it. */
 155                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 156                         return -ENOENT;
 157                 prio = TC_H_MAKE(0x80000000U,0U);
 158         }
 159
 160         /* Find head of filter chain. */
 161
 162         /* Find link */
 163         if ((dev = __dev_get_by_index(&init_net, t->tcm_ifindex)) == NULL)
 164                 return -ENODEV;
 165
 166         /* Find qdisc */
 167         if (!parent) {
 168                 q = dev->qdisc_sleeping;
 169                 parent = q->handle;
 170         } else if ((q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent))) == NULL)
 171                 return -EINVAL;
 172
 173         /* Is it classful? */
 174         if ((cops = q->ops->cl_ops) == NULL)
 175                 return -EINVAL;
 176
 177         /* Do we search for filter, attached to class? */
 178         if (TC_H_MIN(parent)) {
 179                 cl = cops->get(q, parent);
 180                 if (cl == 0)
 181                         return -ENOENT;
 182         }
 183
 184         /* And the last stroke */
 185         chain = cops->tcf_chain(q, cl);
 186         err = -EINVAL;
 187         if (chain == NULL)
 188                 goto errout;
 189
 190         /* Check the chain for existence of proto-tcf with this priority */
 191         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 192                 if (tp->prio >= prio) {
 193                         if (tp->prio == prio) {
 194                                 if (!nprio || (tp->protocol != protocol && protocol))
 195                                         goto errout;
 196                         } else
 197                                 tp = NULL;
 198                         break;
 199                 }
 200         }
 201
 202         if (tp == NULL) {
 203                 /* Proto-tcf does not exist, create new one */
 204
 205                 if (tca[TCA_KIND-1] == NULL || !protocol)
 206                         goto errout;
 207
 208                 err = -ENOENT;
 209                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 210                         goto errout;
 211
 212
 213                 /* Create new proto tcf */
 214
 215                 err = -ENOBUFS;
 216                 if ((tp = kzalloc(sizeof(*tp), GFP_KERNEL)) == NULL)
 217                         goto errout;
 218                 err = -EINVAL;
 219                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
 220                 if (tp_ops == NULL) {
 221 #ifdef CONFIG_KMOD
 222                         struct rtattr *kind = tca[TCA_KIND-1];
 223                         char name[IFNAMSIZ];
 224
 225                         if (kind != NULL &&
 226                             rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 227                                 rtnl_unlock();
 228                                 request_module("cls_%s", name);
 229                                 rtnl_lock();
 230                                 tp_ops = tcf_proto_lookup_ops(kind);
 231                                 /* We dropped the RTNL semaphore in order to
 232                                  * perform the module load.  So, even if we
 233                                  * succeeded in loading the module we have to
 234                                  * replay the request.  We indicate this using
 235                                  * -EAGAIN.
 236                                  */
 237                                 if (tp_ops != NULL) {
 238                                         module_put(tp_ops->owner);
 239                                         err = -EAGAIN;
 240                                 }
 241                         }
 242 #endif
 243                         kfree(tp);
 244                         goto errout;
 245                 }
 246                 tp->ops = tp_ops;
 247                 tp->protocol = protocol;
 248                 tp->prio = nprio ? : tcf_auto_prio(*back);
 249                 tp->q = q;
 250                 tp->classify = tp_ops->classify;
 251                 tp->classid = parent;
 252                 if ((err = tp_ops->init(tp)) != 0) {
 253                         module_put(tp_ops->owner);
 254                         kfree(tp);
 255                         goto errout;
 256                 }
 257
 258                 qdisc_lock_tree(dev);
 259                 tp->next = *back;
 260                 *back = tp;
 261                 qdisc_unlock_tree(dev);
 262
 263         } else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
 264                 goto errout;
 265
 266         fh = tp->ops->get(tp, t->tcm_handle);
 267
 268         if (fh == 0) {
 269                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 270                         qdisc_lock_tree(dev);
 271                         *back = tp->next;
 272                         qdisc_unlock_tree(dev);
 273
 274                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 275                         tcf_destroy(tp);
 276                         err = 0;
 277                         goto errout;
 278                 }
 279
 280                 err = -ENOENT;
 281                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 282                         goto errout;
 283         } else {
 284                 switch (n->nlmsg_type) {
 285                 case RTM_NEWTFILTER:
 286                         err = -EEXIST;
 287                         if (n->nlmsg_flags&NLM_F_EXCL)
 288                                 goto errout;
 289                         break;
 290                 case RTM_DELTFILTER:
 291                         err = tp->ops->delete(tp, fh);
 292                         if (err == 0)
 293                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 294                         goto errout;
 295                 case RTM_GETTFILTER:
 296                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 297                         goto errout;
 298                 default:
 299                         err = -EINVAL;
 300                         goto errout;
 301                 }
 302         }
 303
 304         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 305         if (err == 0)
 306                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 307
 308 errout:
 309         if (cl)
 310                 cops->put(q, cl);
 311         if (err == -EAGAIN)
 312                 /* Replay the request. */
 313                 goto replay;
 314         return err;
 315 }
 316
 317 static int
 318 tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, unsigned long fh,
 319               u32 pid, u32 seq, u16 flags, int event)
 320 {
 321         struct tcmsg *tcm;
 322         struct nlmsghdr  *nlh;
 323         unsigned char *b = skb_tail_pointer(skb);
 324
 325         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 326         tcm = NLMSG_DATA(nlh);
 327         tcm->tcm_family = AF_UNSPEC;
 328         tcm->tcm__pad1 = 0;
 329         tcm->tcm__pad1 = 0;
 330         tcm->tcm_ifindex = tp->q->dev->ifindex;
 331         tcm->tcm_parent = tp->classid;
 332         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 333         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
 334         tcm->tcm_handle = fh;
 335         if (RTM_DELTFILTER != event) {
 336                 tcm->tcm_handle = 0;
 337                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 338                         goto rtattr_failure;
 339         }
 340         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 341         return skb->len;
 342
 343 nlmsg_failure:
 344 rtattr_failure:
 345         nlmsg_trim(skb, b);
 346         return -1;
 347 }
 348
 349 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 350                           struct tcf_proto *tp, unsigned long fh, int event)
 351 {
 352         struct sk_buff *skb;
 353         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 354
 355         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 356         if (!skb)
 357                 return -ENOBUFS;
 358
 359         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 360                 kfree_skb(skb);
 361                 return -EINVAL;
 362         }
 363
 364         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
 365 }
 366
 367 struct tcf_dump_args
 368 {
 369         struct tcf_walker w;
 370         struct sk_buff *skb;
 371         struct netlink_callback *cb;
 372 };
 373
 374 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, struct tcf_walker *arg)
 375 {
 376         struct tcf_dump_args *a = (void*)arg;
 377
 378         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 379                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 380 }
 381
 382 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 383 {
 384         struct net *net = skb->sk->sk_net;
 385         int t;
 386         int s_t;
 387         struct net_device *dev;
 388         struct Qdisc *q;
 389         struct tcf_proto *tp, **chain;
 390         struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
 391         unsigned long cl = 0;
 392         const struct Qdisc_class_ops *cops;
 393         struct tcf_dump_args arg;
 394
 395         if (net != &init_net)
 396                 return 0;
 397
 398         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 399                 return skb->len;
 400         if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 401                 return skb->len;
 402
 403         if (!tcm->tcm_parent)
 404                 q = dev->qdisc_sleeping;
 405         else
 406                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 407         if (!q)
 408                 goto out;
 409         if ((cops = q->ops->cl_ops) == NULL)
 410                 goto errout;
 411         if (TC_H_MIN(tcm->tcm_parent)) {
 412                 cl = cops->get(q, tcm->tcm_parent);
 413                 if (cl == 0)
 414                         goto errout;
 415         }
 416         chain = cops->tcf_chain(q, cl);
 417         if (chain == NULL)
 418                 goto errout;
 419
 420         s_t = cb->args[0];
 421
 422         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 423                 if (t < s_t) continue;
 424                 if (TC_H_MAJ(tcm->tcm_info) &&
 425                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 426                         continue;
 427                 if (TC_H_MIN(tcm->tcm_info) &&
 428                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 429                         continue;
 430                 if (t > s_t)
 431                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 432                 if (cb->args[1] == 0) {
 433                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 434                                           cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER) <= 0) {
 435                                 break;
 436                         }
 437                         cb->args[1] = 1;
 438                 }
 439                 if (tp->ops->walk == NULL)
 440                         continue;
 441                 arg.w.fn = tcf_node_dump;
 442                 arg.skb = skb;
 443                 arg.cb = cb;
 444                 arg.w.stop = 0;
 445                 arg.w.skip = cb->args[1]-1;
 446                 arg.w.count = 0;
 447                 tp->ops->walk(tp, &arg.w);
 448                 cb->args[1] = arg.w.count+1;
 449                 if (arg.w.stop)
 450                         break;
 451         }
 452
 453         cb->args[0] = t;
 454
 455 errout:
 456         if (cl)
 457                 cops->put(q, cl);
 458 out:
 459         dev_put(dev);
 460         return skb->len;
 461 }
 462
 463 void
 464 tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 465 {
 466 #ifdef CONFIG_NET_CLS_ACT
 467         if (exts->action) {
 468                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 469                 exts->action = NULL;
 470         }
 471 #endif
 472 }
 473
 474
 475 int
 476 tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
 477                   struct rtattr *rate_tlv, struct tcf_exts *exts,
 478                   struct tcf_ext_map *map)
 479 {
 480         memset(exts, 0, sizeof(*exts));
 481
 482 #ifdef CONFIG_NET_CLS_ACT
 483         {
 484                 int err;
 485                 struct tc_action *act;
 486
 487                 if (map->police && tb[map->police-1]) {
 488                         act = tcf_action_init_1(tb[map->police-1], rate_tlv, "police",
 489                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 490                         if (act == NULL)
 491                                 return err;
 492
 493                         act->type = TCA_OLD_COMPAT;
 494                         exts->action = act;
 495                 } else if (map->action && tb[map->action-1]) {
 496                         act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
 497                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 498                         if (act == NULL)
 499                                 return err;
 500
 501                         exts->action = act;
 502                 }
 503         }
 504 #else
 505         if ((map->action && tb[map->action-1]) ||
 506             (map->police && tb[map->police-1]))
 507                 return -EOPNOTSUPP;
 508 #endif
 509
 510         return 0;
 511 }
 512
 513 void
 514 tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 515                 struct tcf_exts *src)
 516 {
 517 #ifdef CONFIG_NET_CLS_ACT
 518         if (src->action) {
 519                 struct tc_action *act;
 520                 tcf_tree_lock(tp);
 521                 act = xchg(&dst->action, src->action);
 522                 tcf_tree_unlock(tp);
 523                 if (act)
 524                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 525         }
 526 #endif
 527 }
 528
 529 int
 530 tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 531               struct tcf_ext_map *map)
 532 {
 533 #ifdef CONFIG_NET_CLS_ACT
 534         if (map->action && exts->action) {
 535                 /*
 536                  * again for backward compatible mode - we want
 537                  * to work with both old and new modes of entering
 538                  * tc data even if iproute2  was newer - jhs
 539                  */
 540                 struct rtattr *p_rta = (struct rtattr *)skb_tail_pointer(skb);
 541
 542                 if (exts->action->type != TCA_OLD_COMPAT) {
 543                         RTA_PUT(skb, map->action, 0, NULL);
 544                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 545                                 goto rtattr_failure;
 546                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
 547                 } else if (map->police) {
 548                         RTA_PUT(skb, map->police, 0, NULL);
 549                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 550                                 goto rtattr_failure;
 551                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
 552                 }
 553         }
 554 #endif
 555         return 0;
 556 rtattr_failure: __attribute__ ((unused))
 557         return -1;
 558 }
 559
 560 int
 561 tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 562                     struct tcf_ext_map *map)
 563 {
 564 #ifdef CONFIG_NET_CLS_ACT
 565         if (exts->action)
 566                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 567                         goto rtattr_failure;
 568 #endif
 569         return 0;
 570 rtattr_failure: __attribute__ ((unused))
 571         return -1;
 572 }
 573
 574 static int __init tc_filter_init(void)
 575 {
 576         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 577         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 578         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 579                                                  tc_dump_tfilter);
 580
 581         return 0;
 582 }
 583
 584 subsys_initcall(tc_filter_init);
 585
 586 EXPORT_SYMBOL(register_tcf_proto_ops);
 587 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 588 EXPORT_SYMBOL(tcf_exts_validate);
 589 EXPORT_SYMBOL(tcf_exts_destroy);
 590 EXPORT_SYMBOL(tcf_exts_change);
 591 EXPORT_SYMBOL(tcf_exts_dump);
 592 EXPORT_SYMBOL(tcf_exts_dump_stats);