linux/net/sched/cls_api.c
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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
  35static struct tcf_proto_ops *tcf_proto_base __read_mostly;
  36
  37/* Protects list of registered TC modules. It is pure SMP lock. */
  38static DEFINE_RWLOCK(cls_mod_lock);
  39
  40/* Find classifier type by string name */
  41
  42static 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
  62int 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;
  75out:
  76        write_unlock(&cls_mod_lock);
  77        return rc;
  78}
  79EXPORT_SYMBOL(register_tcf_proto_ops);
  80
  81int 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;
  95out:
  96        write_unlock(&cls_mod_lock);
  97        return rc;
  98}
  99EXPORT_SYMBOL(unregister_tcf_proto_ops);
 100
 101static 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
 107static 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
 119static 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
 142replay:
 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
 320errout:
 321        if (cl)
 322                cops->put(q, cl);
 323        if (err == -EAGAIN)
 324                /* Replay the request. */
 325                goto replay;
 326        return err;
 327}
 328
 329static 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
 354nlmsg_failure:
 355nla_put_failure:
 356        nlmsg_trim(skb, b);
 357        return -1;
 358}
 359
 360static 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
 379struct tcf_dump_args {
 380        struct tcf_walker w;
 381        struct sk_buff *skb;
 382        struct netlink_callback *cb;
 383};
 384
 385static 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
 394static 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
 470errout:
 471        if (cl)
 472                cops->put(q, cl);
 473out:
 474        dev_put(dev);
 475        return skb->len;
 476}
 477
 478void 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}
 487EXPORT_SYMBOL(tcf_exts_destroy);
 488
 489int 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}
 525EXPORT_SYMBOL(tcf_exts_validate);
 526
 527void 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}
 542EXPORT_SYMBOL(tcf_exts_change);
 543
 544int 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;
 574nla_put_failure: __attribute__ ((unused))
 575        return -1;
 576}
 577EXPORT_SYMBOL(tcf_exts_dump);
 578
 579
 580int 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;
 589nla_put_failure: __attribute__ ((unused))
 590        return -1;
 591}
 592EXPORT_SYMBOL(tcf_exts_dump_stats);
 593
 594static 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
 604subsys_initcall(tc_filter_init);
 605