net/sched/cls_api.c

   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/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/string.h>
  24 #include <linux/mm.h>
  25 #include <linux/socket.h>
  26 #include <linux/sockios.h>
  27 #include <linux/in.h>
  28 #include <linux/errno.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/rtnetlink.h>
  33 #include <linux/init.h>
  34 #include <linux/kmod.h>
  35 #include <net/sock.h>
  36 #include <net/pkt_sched.h>
  37 #include <net/pkt_cls.h>
  38
  39 #if 0 /* control */
  40 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  41 #else
  42 #define DPRINTK(format,args...)
  43 #endif
  44
  45 /* The list of all installed classifier types */
  46
  47 static struct tcf_proto_ops *tcf_proto_base;
  48
  49 /* Protects list of registered TC modules. It is pure SMP lock. */
  50 static DEFINE_RWLOCK(cls_mod_lock);
  51
  52 /* Find classifier type by string name */
  53
  54 static struct tcf_proto_ops * tcf_proto_lookup_ops(struct rtattr *kind)
  55 {
  56         struct tcf_proto_ops *t = NULL;
  57
  58         if (kind) {
  59                 read_lock(&cls_mod_lock);
  60                 for (t = tcf_proto_base; t; t = t->next) {
  61                         if (rtattr_strcmp(kind, t->kind) == 0) {
  62                                 if (!try_module_get(t->owner))
  63                                         t = NULL;
  64                                 break;
  65                         }
  66                 }
  67                 read_unlock(&cls_mod_lock);
  68         }
  69         return t;
  70 }
  71
  72 /* Register(unregister) new classifier type */
  73
  74 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  75 {
  76         struct tcf_proto_ops *t, **tp;
  77         int rc = -EEXIST;
  78
  79         write_lock(&cls_mod_lock);
  80         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  81                 if (!strcmp(ops->kind, t->kind))
  82                         goto out;
  83
  84         ops->next = NULL;
  85         *tp = ops;
  86         rc = 0;
  87 out:
  88         write_unlock(&cls_mod_lock);
  89         return rc;
  90 }
  91
  92 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  93 {
  94         struct tcf_proto_ops *t, **tp;
  95         int rc = -ENOENT;
  96
  97         write_lock(&cls_mod_lock);
  98         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
  99                 if (t == ops)
 100                         break;
 101
 102         if (!t)
 103                 goto out;
 104         *tp = t->next;
 105         rc = 0;
 106 out:
 107         write_unlock(&cls_mod_lock);
 108         return rc;
 109 }
 110
 111 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 112                           struct tcf_proto *tp, unsigned long fh, int event);
 113
 114
 115 /* Select new prio value from the range, managed by kernel. */
 116
 117 static __inline__ u32 tcf_auto_prio(struct tcf_proto *tp)
 118 {
 119         u32 first = TC_H_MAKE(0xC0000000U,0U);
 120
 121         if (tp)
 122                 first = tp->prio-1;
 123
 124         return first;
 125 }
 126
 127 /* Add/change/delete/get a filter node */
 128
 129 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 130 {
 131         struct rtattr **tca;
 132         struct tcmsg *t;
 133         u32 protocol;
 134         u32 prio;
 135         u32 nprio;
 136         u32 parent;
 137         struct net_device *dev;
 138         struct Qdisc  *q;
 139         struct tcf_proto **back, **chain;
 140         struct tcf_proto *tp;
 141         struct tcf_proto_ops *tp_ops;
 142         struct Qdisc_class_ops *cops;
 143         unsigned long cl;
 144         unsigned long fh;
 145         int err;
 146
 147 replay:
 148         tca = arg;
 149         t = NLMSG_DATA(n);
 150         protocol = TC_H_MIN(t->tcm_info);
 151         prio = TC_H_MAJ(t->tcm_info);
 152         nprio = prio;
 153         parent = t->tcm_parent;
 154         cl = 0;
 155
 156         if (prio == 0) {
 157                 /* If no priority is given, user wants we allocated it. */
 158                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 159                         return -ENOENT;
 160                 prio = TC_H_MAKE(0x80000000U,0U);
 161         }
 162
 163         /* Find head of filter chain. */
 164
 165         /* Find link */
 166         if ((dev = __dev_get_by_index(t->tcm_ifindex)) == NULL)
 167                 return -ENODEV;
 168
 169         /* Find qdisc */
 170         if (!parent) {
 171                 q = dev->qdisc_sleeping;
 172                 parent = q->handle;
 173         } else if ((q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent))) == NULL)
 174                 return -EINVAL;
 175
 176         /* Is it classful? */
 177         if ((cops = q->ops->cl_ops) == NULL)
 178                 return -EINVAL;
 179
 180         /* Do we search for filter, attached to class? */
 181         if (TC_H_MIN(parent)) {
 182                 cl = cops->get(q, parent);
 183                 if (cl == 0)
 184                         return -ENOENT;
 185         }
 186
 187         /* And the last stroke */
 188         chain = cops->tcf_chain(q, cl);
 189         err = -EINVAL;
 190         if (chain == NULL)
 191                 goto errout;
 192
 193         /* Check the chain for existence of proto-tcf with this priority */
 194         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 195                 if (tp->prio >= prio) {
 196                         if (tp->prio == prio) {
 197                                 if (!nprio || (tp->protocol != protocol && protocol))
 198                                         goto errout;
 199                         } else
 200                                 tp = NULL;
 201                         break;
 202                 }
 203         }
 204
 205         if (tp == NULL) {
 206                 /* Proto-tcf does not exist, create new one */
 207
 208                 if (tca[TCA_KIND-1] == NULL || !protocol)
 209                         goto errout;
 210
 211                 err = -ENOENT;
 212                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 213                         goto errout;
 214
 215
 216                 /* Create new proto tcf */
 217
 218                 err = -ENOBUFS;
 219                 if ((tp = kzalloc(sizeof(*tp), GFP_KERNEL)) == NULL)
 220                         goto errout;
 221                 err = -EINVAL;
 222                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
 223                 if (tp_ops == NULL) {
 224 #ifdef CONFIG_KMOD
 225                         struct rtattr *kind = tca[TCA_KIND-1];
 226                         char name[IFNAMSIZ];
 227
 228                         if (kind != NULL &&
 229                             rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 230                                 rtnl_unlock();
 231                                 request_module("cls_%s", name);
 232                                 rtnl_lock();
 233                                 tp_ops = tcf_proto_lookup_ops(kind);
 234                                 /* We dropped the RTNL semaphore in order to
 235                                  * perform the module load.  So, even if we
 236                                  * succeeded in loading the module we have to
 237                                  * replay the request.  We indicate this using
 238                                  * -EAGAIN.
 239                                  */
 240                                 if (tp_ops != NULL) {
 241                                         module_put(tp_ops->owner);
 242                                         err = -EAGAIN;
 243                                 }
 244                         }
 245 #endif
 246                         kfree(tp);
 247                         goto errout;
 248                 }
 249                 tp->ops = tp_ops;
 250                 tp->protocol = protocol;
 251                 tp->prio = nprio ? : tcf_auto_prio(*back);
 252                 tp->q = q;
 253                 tp->classify = tp_ops->classify;
 254                 tp->classid = parent;
 255                 if ((err = tp_ops->init(tp)) != 0) {
 256                         module_put(tp_ops->owner);
 257                         kfree(tp);
 258                         goto errout;
 259                 }
 260
 261                 qdisc_lock_tree(dev);
 262                 tp->next = *back;
 263                 *back = tp;
 264                 qdisc_unlock_tree(dev);
 265
 266         } else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
 267                 goto errout;
 268
 269         fh = tp->ops->get(tp, t->tcm_handle);
 270
 271         if (fh == 0) {
 272                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 273                         qdisc_lock_tree(dev);
 274                         *back = tp->next;
 275                         qdisc_unlock_tree(dev);
 276
 277                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 278                         tcf_destroy(tp);
 279                         err = 0;
 280                         goto errout;
 281                 }
 282
 283                 err = -ENOENT;
 284                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 285                         goto errout;
 286         } else {
 287                 switch (n->nlmsg_type) {
 288                 case RTM_NEWTFILTER:
 289                         err = -EEXIST;
 290                         if (n->nlmsg_flags&NLM_F_EXCL)
 291                                 goto errout;
 292                         break;
 293                 case RTM_DELTFILTER:
 294                         err = tp->ops->delete(tp, fh);
 295                         if (err == 0)
 296                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 297                         goto errout;
 298                 case RTM_GETTFILTER:
 299                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 300                         goto errout;
 301                 default:
 302                         err = -EINVAL;
 303                         goto errout;
 304                 }
 305         }
 306
 307         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 308         if (err == 0)
 309                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 310
 311 errout:
 312         if (cl)
 313                 cops->put(q, cl);
 314         if (err == -EAGAIN)
 315                 /* Replay the request. */
 316                 goto replay;
 317         return err;
 318 }
 319
 320 static int
 321 tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, unsigned long fh,
 322               u32 pid, u32 seq, u16 flags, int event)
 323 {
 324         struct tcmsg *tcm;
 325         struct nlmsghdr  *nlh;
 326         unsigned char    *b = skb->tail;
 327
 328         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 329         tcm = NLMSG_DATA(nlh);
 330         tcm->tcm_family = AF_UNSPEC;
 331         tcm->tcm__pad1 = 0;
 332         tcm->tcm__pad1 = 0;
 333         tcm->tcm_ifindex = tp->q->dev->ifindex;
 334         tcm->tcm_parent = tp->classid;
 335         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 336         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
 337         tcm->tcm_handle = fh;
 338         if (RTM_DELTFILTER != event) {
 339                 tcm->tcm_handle = 0;
 340                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 341                         goto rtattr_failure;
 342         }
 343         nlh->nlmsg_len = skb->tail - b;
 344         return skb->len;
 345
 346 nlmsg_failure:
 347 rtattr_failure:
 348         skb_trim(skb, b - skb->data);
 349         return -1;
 350 }
 351
 352 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 353                           struct tcf_proto *tp, unsigned long fh, int event)
 354 {
 355         struct sk_buff *skb;
 356         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 357
 358         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 359         if (!skb)
 360                 return -ENOBUFS;
 361
 362         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 363                 kfree_skb(skb);
 364                 return -EINVAL;
 365         }
 366
 367         return rtnetlink_send(skb, pid, RTNLGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
 368 }
 369
 370 struct tcf_dump_args
 371 {
 372         struct tcf_walker w;
 373         struct sk_buff *skb;
 374         struct netlink_callback *cb;
 375 };
 376
 377 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, struct tcf_walker *arg)
 378 {
 379         struct tcf_dump_args *a = (void*)arg;
 380
 381         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 382                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 383 }
 384
 385 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 386 {
 387         int t;
 388         int s_t;
 389         struct net_device *dev;
 390         struct Qdisc *q;
 391         struct tcf_proto *tp, **chain;
 392         struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
 393         unsigned long cl = 0;
 394         struct Qdisc_class_ops *cops;
 395         struct tcf_dump_args arg;
 396
 397         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 398                 return skb->len;
 399         if ((dev = dev_get_by_index(tcm->tcm_ifindex)) == NULL)
 400                 return skb->len;
 401
 402         read_lock(&qdisc_tree_lock);
 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         read_unlock(&qdisc_tree_lock);
 460         dev_put(dev);
 461         return skb->len;
 462 }
 463
 464 void
 465 tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 466 {
 467 #ifdef CONFIG_NET_CLS_ACT
 468         if (exts->action) {
 469                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 470                 exts->action = NULL;
 471         }
 472 #elif defined CONFIG_NET_CLS_POLICE
 473         if (exts->police) {
 474                 tcf_police_release(exts->police, TCA_ACT_UNBIND);
 475                 exts->police = NULL;
 476         }
 477 #endif
 478 }
 479
 480
 481 int
 482 tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
 483                   struct rtattr *rate_tlv, struct tcf_exts *exts,
 484                   struct tcf_ext_map *map)
 485 {
 486         memset(exts, 0, sizeof(*exts));
 487
 488 #ifdef CONFIG_NET_CLS_ACT
 489         {
 490                 int err;
 491                 struct tc_action *act;
 492
 493                 if (map->police && tb[map->police-1]) {
 494                         act = tcf_action_init_1(tb[map->police-1], rate_tlv, "police",
 495                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 496                         if (act == NULL)
 497                                 return err;
 498
 499                         act->type = TCA_OLD_COMPAT;
 500                         exts->action = act;
 501                 } else if (map->action && tb[map->action-1]) {
 502                         act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
 503                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
 504                         if (act == NULL)
 505                                 return err;
 506
 507                         exts->action = act;
 508                 }
 509         }
 510 #elif defined CONFIG_NET_CLS_POLICE
 511         if (map->police && tb[map->police-1]) {
 512                 struct tcf_police *p;
 513
 514                 p = tcf_police_locate(tb[map->police-1], rate_tlv);
 515                 if (p == NULL)
 516                         return -EINVAL;
 517
 518                 exts->police = p;
 519         } else if (map->action && tb[map->action-1])
 520                 return -EOPNOTSUPP;
 521 #else
 522         if ((map->action && tb[map->action-1]) ||
 523             (map->police && tb[map->police-1]))
 524                 return -EOPNOTSUPP;
 525 #endif
 526
 527         return 0;
 528 }
 529
 530 void
 531 tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 532                 struct tcf_exts *src)
 533 {
 534 #ifdef CONFIG_NET_CLS_ACT
 535         if (src->action) {
 536                 struct tc_action *act;
 537                 tcf_tree_lock(tp);
 538                 act = xchg(&dst->action, src->action);
 539                 tcf_tree_unlock(tp);
 540                 if (act)
 541                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 542         }
 543 #elif defined CONFIG_NET_CLS_POLICE
 544         if (src->police) {
 545                 struct tcf_police *p;
 546                 tcf_tree_lock(tp);
 547                 p = xchg(&dst->police, src->police);
 548                 tcf_tree_unlock(tp);
 549                 if (p)
 550                         tcf_police_release(p, TCA_ACT_UNBIND);
 551         }
 552 #endif
 553 }
 554
 555 int
 556 tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 557               struct tcf_ext_map *map)
 558 {
 559 #ifdef CONFIG_NET_CLS_ACT
 560         if (map->action && exts->action) {
 561                 /*
 562                  * again for backward compatible mode - we want
 563                  * to work with both old and new modes of entering
 564                  * tc data even if iproute2  was newer - jhs
 565                  */
 566                 struct rtattr * p_rta = (struct rtattr*) skb->tail;
 567
 568                 if (exts->action->type != TCA_OLD_COMPAT) {
 569                         RTA_PUT(skb, map->action, 0, NULL);
 570                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 571                                 goto rtattr_failure;
 572                         p_rta->rta_len = skb->tail - (u8*)p_rta;
 573                 } else if (map->police) {
 574                         RTA_PUT(skb, map->police, 0, NULL);
 575                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 576                                 goto rtattr_failure;
 577                         p_rta->rta_len = skb->tail - (u8*)p_rta;
 578                 }
 579         }
 580 #elif defined CONFIG_NET_CLS_POLICE
 581         if (map->police && exts->police) {
 582                 struct rtattr * p_rta = (struct rtattr*) skb->tail;
 583
 584                 RTA_PUT(skb, map->police, 0, NULL);
 585
 586                 if (tcf_police_dump(skb, exts->police) < 0)
 587                         goto rtattr_failure;
 588
 589                 p_rta->rta_len = skb->tail - (u8*)p_rta;
 590         }
 591 #endif
 592         return 0;
 593 rtattr_failure: __attribute__ ((unused))
 594         return -1;
 595 }
 596
 597 int
 598 tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 599                     struct tcf_ext_map *map)
 600 {
 601 #ifdef CONFIG_NET_CLS_ACT
 602         if (exts->action)
 603                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 604                         goto rtattr_failure;
 605 #elif defined CONFIG_NET_CLS_POLICE
 606         if (exts->police)
 607                 if (tcf_police_dump_stats(skb, exts->police) < 0)
 608                         goto rtattr_failure;
 609 #endif
 610         return 0;
 611 rtattr_failure: __attribute__ ((unused))
 612         return -1;
 613 }
 614
 615 static int __init tc_filter_init(void)
 616 {
 617         struct rtnetlink_link *link_p = rtnetlink_links[PF_UNSPEC];
 618
 619         /* Setup rtnetlink links. It is made here to avoid
 620            exporting large number of public symbols.
 621          */
 622
 623         if (link_p) {
 624                 link_p[RTM_NEWTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 625                 link_p[RTM_DELTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 626                 link_p[RTM_GETTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
 627                 link_p[RTM_GETTFILTER-RTM_BASE].dumpit = tc_dump_tfilter;
 628         }
 629         return 0;
 630 }
 631
 632 subsys_initcall(tc_filter_init);
 633
 634 EXPORT_SYMBOL(register_tcf_proto_ops);
 635 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 636 EXPORT_SYMBOL(tcf_exts_validate);
 637 EXPORT_SYMBOL(tcf_exts_destroy);
 638 EXPORT_SYMBOL(tcf_exts_change);
 639 EXPORT_SYMBOL(tcf_exts_dump);
 640 EXPORT_SYMBOL(tcf_exts_dump_stats);