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 <linux/slab.h>
  28#include <net/net_namespace.h>
  29#include <net/sock.h>
  30#include <net/netlink.h>
  31#include <net/pkt_sched.h>
  32#include <net/pkt_cls.h>
  33
  34/* The list of all installed classifier types */
  35
  36static struct tcf_proto_ops *tcf_proto_base __read_mostly;
  37
  38/* Protects list of registered TC modules. It is pure SMP lock. */
  39static DEFINE_RWLOCK(cls_mod_lock);
  40
  41/* Find classifier type by string name */
  42
  43static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
  44{
  45        const struct tcf_proto_ops *t = NULL;
  46
  47        if (kind) {
  48                read_lock(&cls_mod_lock);
  49                for (t = tcf_proto_base; t; t = t->next) {
  50                        if (nla_strcmp(kind, t->kind) == 0) {
  51                                if (!try_module_get(t->owner))
  52                                        t = NULL;
  53                                break;
  54                        }
  55                }
  56                read_unlock(&cls_mod_lock);
  57        }
  58        return t;
  59}
  60
  61/* Register(unregister) new classifier type */
  62
  63int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  64{
  65        struct tcf_proto_ops *t, **tp;
  66        int rc = -EEXIST;
  67
  68        write_lock(&cls_mod_lock);
  69        for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  70                if (!strcmp(ops->kind, t->kind))
  71                        goto out;
  72
  73        ops->next = NULL;
  74        *tp = ops;
  75        rc = 0;
  76out:
  77        write_unlock(&cls_mod_lock);
  78        return rc;
  79}
  80EXPORT_SYMBOL(register_tcf_proto_ops);
  81
  82int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  83{
  84        struct tcf_proto_ops *t, **tp;
  85        int rc = -ENOENT;
  86
  87        write_lock(&cls_mod_lock);
  88        for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  89                if (t == ops)
  90                        break;
  91
  92        if (!t)
  93                goto out;
  94        *tp = t->next;
  95        rc = 0;
  96out:
  97        write_unlock(&cls_mod_lock);
  98        return rc;
  99}
 100EXPORT_SYMBOL(unregister_tcf_proto_ops);
 101
 102static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 103                          struct nlmsghdr *n, struct tcf_proto *tp,
 104                          unsigned long fh, int event);
 105
 106
 107/* Select new prio value from the range, managed by kernel. */
 108
 109static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 110{
 111        u32 first = TC_H_MAKE(0xC0000000U, 0U);
 112
 113        if (tp)
 114                first = tp->prio - 1;
 115
 116        return first;
 117}
 118
 119/* Add/change/delete/get a filter node */
 120
 121static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 122{
 123        struct net *net = sock_net(skb->sk);
 124        struct nlattr *tca[TCA_MAX + 1];
 125        spinlock_t *root_lock;
 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        const 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        int tp_created = 0;
 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 ||
 153                    !(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(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        cops = q->ops->cl_ops;
 181        if (!cops)
 182                return -EINVAL;
 183
 184        if (cops->tcf_chain == NULL)
 185                return -EOPNOTSUPP;
 186
 187        /* Do we search for filter, attached to class? */
 188        if (TC_H_MIN(parent)) {
 189                cl = cops->get(q, parent);
 190                if (cl == 0)
 191                        return -ENOENT;
 192        }
 193
 194        /* And the last stroke */
 195        chain = cops->tcf_chain(q, cl);
 196        err = -EINVAL;
 197        if (chain == NULL)
 198                goto errout;
 199
 200        /* Check the chain for existence of proto-tcf with this priority */
 201        for (back = chain; (tp = *back) != NULL; back = &tp->next) {
 202                if (tp->prio >= prio) {
 203                        if (tp->prio == prio) {
 204                                if (!nprio ||
 205                                    (tp->protocol != protocol && protocol))
 206                                        goto errout;
 207                        } else
 208                                tp = NULL;
 209                        break;
 210                }
 211        }
 212
 213        root_lock = qdisc_root_sleeping_lock(q);
 214
 215        if (tp == NULL) {
 216                /* Proto-tcf does not exist, create new one */
 217
 218                if (tca[TCA_KIND] == NULL || !protocol)
 219                        goto errout;
 220
 221                err = -ENOENT;
 222                if (n->nlmsg_type != RTM_NEWTFILTER ||
 223                    !(n->nlmsg_flags & NLM_F_CREATE))
 224                        goto errout;
 225
 226
 227                /* Create new proto tcf */
 228
 229                err = -ENOBUFS;
 230                tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 231                if (tp == NULL)
 232                        goto errout;
 233                err = -ENOENT;
 234                tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 235                if (tp_ops == NULL) {
 236#ifdef CONFIG_MODULES
 237                        struct nlattr *kind = tca[TCA_KIND];
 238                        char name[IFNAMSIZ];
 239
 240                        if (kind != NULL &&
 241                            nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 242                                rtnl_unlock();
 243                                request_module("cls_%s", name);
 244                                rtnl_lock();
 245                                tp_ops = tcf_proto_lookup_ops(kind);
 246                                /* We dropped the RTNL semaphore in order to
 247                                 * perform the module load.  So, even if we
 248                                 * succeeded in loading the module we have to
 249                                 * replay the request.  We indicate this using
 250                                 * -EAGAIN.
 251                                 */
 252                                if (tp_ops != NULL) {
 253                                        module_put(tp_ops->owner);
 254                                        err = -EAGAIN;
 255                                }
 256                        }
 257#endif
 258                        kfree(tp);
 259                        goto errout;
 260                }
 261                tp->ops = tp_ops;
 262                tp->protocol = protocol;
 263                tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
 264                tp->q = q;
 265                tp->classify = tp_ops->classify;
 266                tp->classid = parent;
 267
 268                err = tp_ops->init(tp);
 269                if (err != 0) {
 270                        module_put(tp_ops->owner);
 271                        kfree(tp);
 272                        goto errout;
 273                }
 274
 275                tp_created = 1;
 276
 277        } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 278                goto errout;
 279
 280        fh = tp->ops->get(tp, t->tcm_handle);
 281
 282        if (fh == 0) {
 283                if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 284                        spin_lock_bh(root_lock);
 285                        *back = tp->next;
 286                        spin_unlock_bh(root_lock);
 287
 288                        tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
 289                        tcf_destroy(tp);
 290                        err = 0;
 291                        goto errout;
 292                }
 293
 294                err = -ENOENT;
 295                if (n->nlmsg_type != RTM_NEWTFILTER ||
 296                    !(n->nlmsg_flags & NLM_F_CREATE))
 297                        goto errout;
 298        } else {
 299                switch (n->nlmsg_type) {
 300                case RTM_NEWTFILTER:
 301                        err = -EEXIST;
 302                        if (n->nlmsg_flags & NLM_F_EXCL) {
 303                                if (tp_created)
 304                                        tcf_destroy(tp);
 305                                goto errout;
 306                        }
 307                        break;
 308                case RTM_DELTFILTER:
 309                        err = tp->ops->delete(tp, fh);
 310                        if (err == 0)
 311                                tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
 312                        goto errout;
 313                case RTM_GETTFILTER:
 314                        err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 315                        goto errout;
 316                default:
 317                        err = -EINVAL;
 318                        goto errout;
 319                }
 320        }
 321
 322        err = tp->ops->change(skb, tp, cl, t->tcm_handle, tca, &fh);
 323        if (err == 0) {
 324                if (tp_created) {
 325                        spin_lock_bh(root_lock);
 326                        tp->next = *back;
 327                        *back = tp;
 328                        spin_unlock_bh(root_lock);
 329                }
 330                tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 331        } else {
 332                if (tp_created)
 333                        tcf_destroy(tp);
 334        }
 335
 336errout:
 337        if (cl)
 338                cops->put(q, cl);
 339        if (err == -EAGAIN)
 340                /* Replay the request. */
 341                goto replay;
 342        return err;
 343}
 344
 345static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 346                         unsigned long fh, u32 portid, u32 seq, u16 flags, int event)
 347{
 348        struct tcmsg *tcm;
 349        struct nlmsghdr  *nlh;
 350        unsigned char *b = skb_tail_pointer(skb);
 351
 352        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 353        if (!nlh)
 354                goto out_nlmsg_trim;
 355        tcm = nlmsg_data(nlh);
 356        tcm->tcm_family = AF_UNSPEC;
 357        tcm->tcm__pad1 = 0;
 358        tcm->tcm__pad2 = 0;
 359        tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 360        tcm->tcm_parent = tp->classid;
 361        tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 362        if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 363                goto nla_put_failure;
 364        tcm->tcm_handle = fh;
 365        if (RTM_DELTFILTER != event) {
 366                tcm->tcm_handle = 0;
 367                if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 368                        goto nla_put_failure;
 369        }
 370        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 371        return skb->len;
 372
 373out_nlmsg_trim:
 374nla_put_failure:
 375        nlmsg_trim(skb, b);
 376        return -1;
 377}
 378
 379static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 380                          struct nlmsghdr *n, struct tcf_proto *tp,
 381                          unsigned long fh, int event)
 382{
 383        struct sk_buff *skb;
 384        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 385
 386        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 387        if (!skb)
 388                return -ENOBUFS;
 389
 390        if (tcf_fill_node(skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) {
 391                kfree_skb(skb);
 392                return -EINVAL;
 393        }
 394
 395        return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 396                              n->nlmsg_flags & NLM_F_ECHO);
 397}
 398
 399struct tcf_dump_args {
 400        struct tcf_walker w;
 401        struct sk_buff *skb;
 402        struct netlink_callback *cb;
 403};
 404
 405static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 406                         struct tcf_walker *arg)
 407{
 408        struct tcf_dump_args *a = (void *)arg;
 409
 410        return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
 411                             a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 412}
 413
 414/* called with RTNL */
 415static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 416{
 417        struct net *net = sock_net(skb->sk);
 418        int t;
 419        int s_t;
 420        struct net_device *dev;
 421        struct Qdisc *q;
 422        struct tcf_proto *tp, **chain;
 423        struct tcmsg *tcm = nlmsg_data(cb->nlh);
 424        unsigned long cl = 0;
 425        const struct Qdisc_class_ops *cops;
 426        struct tcf_dump_args arg;
 427
 428        if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 429                return skb->len;
 430        dev = __dev_get_by_index(net, tcm->tcm_ifindex);
 431        if (!dev)
 432                return skb->len;
 433
 434        if (!tcm->tcm_parent)
 435                q = dev->qdisc;
 436        else
 437                q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 438        if (!q)
 439                goto out;
 440        cops = q->ops->cl_ops;
 441        if (!cops)
 442                goto errout;
 443        if (cops->tcf_chain == NULL)
 444                goto errout;
 445        if (TC_H_MIN(tcm->tcm_parent)) {
 446                cl = cops->get(q, tcm->tcm_parent);
 447                if (cl == 0)
 448                        goto errout;
 449        }
 450        chain = cops->tcf_chain(q, cl);
 451        if (chain == NULL)
 452                goto errout;
 453
 454        s_t = cb->args[0];
 455
 456        for (tp = *chain, t = 0; tp; tp = tp->next, t++) {
 457                if (t < s_t)
 458                        continue;
 459                if (TC_H_MAJ(tcm->tcm_info) &&
 460                    TC_H_MAJ(tcm->tcm_info) != tp->prio)
 461                        continue;
 462                if (TC_H_MIN(tcm->tcm_info) &&
 463                    TC_H_MIN(tcm->tcm_info) != tp->protocol)
 464                        continue;
 465                if (t > s_t)
 466                        memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 467                if (cb->args[1] == 0) {
 468                        if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).portid,
 469                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
 470                                          RTM_NEWTFILTER) <= 0)
 471                                break;
 472
 473                        cb->args[1] = 1;
 474                }
 475                if (tp->ops->walk == NULL)
 476                        continue;
 477                arg.w.fn = tcf_node_dump;
 478                arg.skb = skb;
 479                arg.cb = cb;
 480                arg.w.stop = 0;
 481                arg.w.skip = cb->args[1] - 1;
 482                arg.w.count = 0;
 483                tp->ops->walk(tp, &arg.w);
 484                cb->args[1] = arg.w.count + 1;
 485                if (arg.w.stop)
 486                        break;
 487        }
 488
 489        cb->args[0] = t;
 490
 491errout:
 492        if (cl)
 493                cops->put(q, cl);
 494out:
 495        return skb->len;
 496}
 497
 498void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 499{
 500#ifdef CONFIG_NET_CLS_ACT
 501        if (exts->action) {
 502                tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 503                exts->action = NULL;
 504        }
 505#endif
 506}
 507EXPORT_SYMBOL(tcf_exts_destroy);
 508
 509int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
 510                  struct nlattr *rate_tlv, struct tcf_exts *exts,
 511                  const struct tcf_ext_map *map)
 512{
 513        memset(exts, 0, sizeof(*exts));
 514
 515#ifdef CONFIG_NET_CLS_ACT
 516        {
 517                struct tc_action *act;
 518
 519                if (map->police && tb[map->police]) {
 520                        act = tcf_action_init_1(tb[map->police], rate_tlv,
 521                                                "police", TCA_ACT_NOREPLACE,
 522                                                TCA_ACT_BIND);
 523                        if (IS_ERR(act))
 524                                return PTR_ERR(act);
 525
 526                        act->type = TCA_OLD_COMPAT;
 527                        exts->action = act;
 528                } else if (map->action && tb[map->action]) {
 529                        act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 530                                              TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 531                        if (IS_ERR(act))
 532                                return PTR_ERR(act);
 533
 534                        exts->action = act;
 535                }
 536        }
 537#else
 538        if ((map->action && tb[map->action]) ||
 539            (map->police && tb[map->police]))
 540                return -EOPNOTSUPP;
 541#endif
 542
 543        return 0;
 544}
 545EXPORT_SYMBOL(tcf_exts_validate);
 546
 547void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 548                     struct tcf_exts *src)
 549{
 550#ifdef CONFIG_NET_CLS_ACT
 551        if (src->action) {
 552                struct tc_action *act;
 553                tcf_tree_lock(tp);
 554                act = dst->action;
 555                dst->action = src->action;
 556                tcf_tree_unlock(tp);
 557                if (act)
 558                        tcf_action_destroy(act, TCA_ACT_UNBIND);
 559        }
 560#endif
 561}
 562EXPORT_SYMBOL(tcf_exts_change);
 563
 564int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 565                  const struct tcf_ext_map *map)
 566{
 567#ifdef CONFIG_NET_CLS_ACT
 568        if (map->action && exts->action) {
 569                /*
 570                 * again for backward compatible mode - we want
 571                 * to work with both old and new modes of entering
 572                 * tc data even if iproute2  was newer - jhs
 573                 */
 574                struct nlattr *nest;
 575
 576                if (exts->action->type != TCA_OLD_COMPAT) {
 577                        nest = nla_nest_start(skb, map->action);
 578                        if (nest == NULL)
 579                                goto nla_put_failure;
 580                        if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 581                                goto nla_put_failure;
 582                        nla_nest_end(skb, nest);
 583                } else if (map->police) {
 584                        nest = nla_nest_start(skb, map->police);
 585                        if (nest == NULL)
 586                                goto nla_put_failure;
 587                        if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 588                                goto nla_put_failure;
 589                        nla_nest_end(skb, nest);
 590                }
 591        }
 592#endif
 593        return 0;
 594nla_put_failure: __attribute__ ((unused))
 595        return -1;
 596}
 597EXPORT_SYMBOL(tcf_exts_dump);
 598
 599
 600int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 601                        const struct tcf_ext_map *map)
 602{
 603#ifdef CONFIG_NET_CLS_ACT
 604        if (exts->action)
 605                if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 606                        goto nla_put_failure;
 607#endif
 608        return 0;
 609nla_put_failure: __attribute__ ((unused))
 610        return -1;
 611}
 612EXPORT_SYMBOL(tcf_exts_dump_stats);
 613
 614static int __init tc_filter_init(void)
 615{
 616        rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL);
 617        rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL);
 618        rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 619                      tc_dump_tfilter, NULL);
 620
 621        return 0;
 622}
 623
 624subsys_initcall(tc_filter_init);
 625
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