net/sched/cls_fw.c

   1 /*
   2  * net/sched/cls_fw.c   Classifier mapping ipchains' fwmark to traffic class.
   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  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
  13  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
  14  * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
  15  *
  16  * JHS: We should remove the CONFIG_NET_CLS_IND from here
  17  * eventually when the meta match extension is made available
  18  *
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/string.h>
  26 #include <linux/errno.h>
  27 #include <linux/skbuff.h>
  28 #include <net/netlink.h>
  29 #include <net/act_api.h>
  30 #include <net/pkt_cls.h>
  31
  32 #define HTSIZE 256
  33
  34 struct fw_head {
  35         u32                     mask;
  36         struct fw_filter __rcu  *ht[HTSIZE];
  37         struct rcu_head         rcu;
  38 };
  39
  40 struct fw_filter {
  41         struct fw_filter __rcu  *next;
  42         u32                     id;
  43         struct tcf_result       res;
  44 #ifdef CONFIG_NET_CLS_IND
  45         int                     ifindex;
  46 #endif /* CONFIG_NET_CLS_IND */
  47         struct tcf_exts         exts;
  48         struct tcf_proto        *tp;
  49         union {
  50                 struct work_struct      work;
  51                 struct rcu_head         rcu;
  52         };
  53 };
  54
  55 static u32 fw_hash(u32 handle)
  56 {
  57         handle ^= (handle >> 16);
  58         handle ^= (handle >> 8);
  59         return handle % HTSIZE;
  60 }
  61
  62 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  63                        struct tcf_result *res)
  64 {
  65         struct fw_head *head = rcu_dereference_bh(tp->root);
  66         struct fw_filter *f;
  67         int r;
  68         u32 id = skb->mark;
  69
  70         if (head != NULL) {
  71                 id &= head->mask;
  72
  73                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  74                      f = rcu_dereference_bh(f->next)) {
  75                         if (f->id == id) {
  76                                 *res = f->res;
  77 #ifdef CONFIG_NET_CLS_IND
  78                                 if (!tcf_match_indev(skb, f->ifindex))
  79                                         continue;
  80 #endif /* CONFIG_NET_CLS_IND */
  81                                 r = tcf_exts_exec(skb, &f->exts, res);
  82                                 if (r < 0)
  83                                         continue;
  84
  85                                 return r;
  86                         }
  87                 }
  88         } else {
  89                 /* Old method: classify the packet using its skb mark. */
  90                 if (id && (TC_H_MAJ(id) == 0 ||
  91                            !(TC_H_MAJ(id ^ tp->q->handle)))) {
  92                         res->classid = id;
  93                         res->class = 0;
  94                         return 0;
  95                 }
  96         }
  97
  98         return -1;
  99 }
 100
 101 static void *fw_get(struct tcf_proto *tp, u32 handle)
 102 {
 103         struct fw_head *head = rtnl_dereference(tp->root);
 104         struct fw_filter *f;
 105
 106         if (head == NULL)
 107                 return NULL;
 108
 109         f = rtnl_dereference(head->ht[fw_hash(handle)]);
 110         for (; f; f = rtnl_dereference(f->next)) {
 111                 if (f->id == handle)
 112                         return f;
 113         }
 114         return NULL;
 115 }
 116
 117 static int fw_init(struct tcf_proto *tp)
 118 {
 119         /* We don't allocate fw_head here, because in the old method
 120          * we don't need it at all.
 121          */
 122         return 0;
 123 }
 124
 125 static void __fw_delete_filter(struct fw_filter *f)
 126 {
 127         tcf_exts_destroy(&f->exts);
 128         tcf_exts_put_net(&f->exts);
 129         kfree(f);
 130 }
 131
 132 static void fw_delete_filter_work(struct work_struct *work)
 133 {
 134         struct fw_filter *f = container_of(work, struct fw_filter, work);
 135
 136         rtnl_lock();
 137         __fw_delete_filter(f);
 138         rtnl_unlock();
 139 }
 140
 141 static void fw_delete_filter(struct rcu_head *head)
 142 {
 143         struct fw_filter *f = container_of(head, struct fw_filter, rcu);
 144
 145         INIT_WORK(&f->work, fw_delete_filter_work);
 146         tcf_queue_work(&f->work);
 147 }
 148
 149 static void fw_destroy(struct tcf_proto *tp)
 150 {
 151         struct fw_head *head = rtnl_dereference(tp->root);
 152         struct fw_filter *f;
 153         int h;
 154
 155         if (head == NULL)
 156                 return;
 157
 158         for (h = 0; h < HTSIZE; h++) {
 159                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 160                         RCU_INIT_POINTER(head->ht[h],
 161                                          rtnl_dereference(f->next));
 162                         tcf_unbind_filter(tp, &f->res);
 163                         if (tcf_exts_get_net(&f->exts))
 164                                 call_rcu(&f->rcu, fw_delete_filter);
 165                         else
 166                                 __fw_delete_filter(f);
 167                 }
 168         }
 169         kfree_rcu(head, rcu);
 170 }
 171
 172 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
 173 {
 174         struct fw_head *head = rtnl_dereference(tp->root);
 175         struct fw_filter *f = arg;
 176         struct fw_filter __rcu **fp;
 177         struct fw_filter *pfp;
 178         int ret = -EINVAL;
 179         int h;
 180
 181         if (head == NULL || f == NULL)
 182                 goto out;
 183
 184         fp = &head->ht[fw_hash(f->id)];
 185
 186         for (pfp = rtnl_dereference(*fp); pfp;
 187              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 188                 if (pfp == f) {
 189                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 190                         tcf_unbind_filter(tp, &f->res);
 191                         tcf_exts_get_net(&f->exts);
 192                         call_rcu(&f->rcu, fw_delete_filter);
 193                         ret = 0;
 194                         break;
 195                 }
 196         }
 197
 198         *last = true;
 199         for (h = 0; h < HTSIZE; h++) {
 200                 if (rcu_access_pointer(head->ht[h])) {
 201                         *last = false;
 202                         break;
 203                 }
 204         }
 205
 206 out:
 207         return ret;
 208 }
 209
 210 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 211         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 212         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 213         [TCA_FW_MASK]           = { .type = NLA_U32 },
 214 };
 215
 216 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 217                         struct fw_filter *f, struct nlattr **tb,
 218                         struct nlattr **tca, unsigned long base, bool ovr)
 219 {
 220         struct fw_head *head = rtnl_dereference(tp->root);
 221         u32 mask;
 222         int err;
 223
 224         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
 225         if (err < 0)
 226                 return err;
 227
 228         if (tb[TCA_FW_CLASSID]) {
 229                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 230                 tcf_bind_filter(tp, &f->res, base);
 231         }
 232
 233 #ifdef CONFIG_NET_CLS_IND
 234         if (tb[TCA_FW_INDEV]) {
 235                 int ret;
 236                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 237                 if (ret < 0)
 238                         return ret;
 239                 f->ifindex = ret;
 240         }
 241 #endif /* CONFIG_NET_CLS_IND */
 242
 243         err = -EINVAL;
 244         if (tb[TCA_FW_MASK]) {
 245                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 246                 if (mask != head->mask)
 247                         return err;
 248         } else if (head->mask != 0xFFFFFFFF)
 249                 return err;
 250
 251         return 0;
 252 }
 253
 254 static int fw_change(struct net *net, struct sk_buff *in_skb,
 255                      struct tcf_proto *tp, unsigned long base,
 256                      u32 handle, struct nlattr **tca, void **arg,
 257                      bool ovr)
 258 {
 259         struct fw_head *head = rtnl_dereference(tp->root);
 260         struct fw_filter *f = *arg;
 261         struct nlattr *opt = tca[TCA_OPTIONS];
 262         struct nlattr *tb[TCA_FW_MAX + 1];
 263         int err;
 264
 265         if (!opt)
 266                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 267
 268         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 269         if (err < 0)
 270                 return err;
 271
 272         if (f) {
 273                 struct fw_filter *pfp, *fnew;
 274                 struct fw_filter __rcu **fp;
 275
 276                 if (f->id != handle && handle)
 277                         return -EINVAL;
 278
 279                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 280                 if (!fnew)
 281                         return -ENOBUFS;
 282
 283                 fnew->id = f->id;
 284                 fnew->res = f->res;
 285 #ifdef CONFIG_NET_CLS_IND
 286                 fnew->ifindex = f->ifindex;
 287 #endif /* CONFIG_NET_CLS_IND */
 288                 fnew->tp = f->tp;
 289
 290                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 291                 if (err < 0) {
 292                         kfree(fnew);
 293                         return err;
 294                 }
 295
 296                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
 297                 if (err < 0) {
 298                         tcf_exts_destroy(&fnew->exts);
 299                         kfree(fnew);
 300                         return err;
 301                 }
 302
 303                 fp = &head->ht[fw_hash(fnew->id)];
 304                 for (pfp = rtnl_dereference(*fp); pfp;
 305                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 306                         if (pfp == f)
 307                                 break;
 308
 309                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 310                 rcu_assign_pointer(*fp, fnew);
 311                 tcf_unbind_filter(tp, &f->res);
 312                 tcf_exts_get_net(&f->exts);
 313                 call_rcu(&f->rcu, fw_delete_filter);
 314
 315                 *arg = fnew;
 316                 return err;
 317         }
 318
 319         if (!handle)
 320                 return -EINVAL;
 321
 322         if (!head) {
 323                 u32 mask = 0xFFFFFFFF;
 324                 if (tb[TCA_FW_MASK])
 325                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 326
 327                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 328                 if (!head)
 329                         return -ENOBUFS;
 330                 head->mask = mask;
 331
 332                 rcu_assign_pointer(tp->root, head);
 333         }
 334
 335         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 336         if (f == NULL)
 337                 return -ENOBUFS;
 338
 339         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 340         if (err < 0)
 341                 goto errout;
 342         f->id = handle;
 343         f->tp = tp;
 344
 345         err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
 346         if (err < 0)
 347                 goto errout;
 348
 349         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 350         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 351
 352         *arg = f;
 353         return 0;
 354
 355 errout:
 356         tcf_exts_destroy(&f->exts);
 357         kfree(f);
 358         return err;
 359 }
 360
 361 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 362 {
 363         struct fw_head *head = rtnl_dereference(tp->root);
 364         int h;
 365
 366         if (head == NULL)
 367                 arg->stop = 1;
 368
 369         if (arg->stop)
 370                 return;
 371
 372         for (h = 0; h < HTSIZE; h++) {
 373                 struct fw_filter *f;
 374
 375                 for (f = rtnl_dereference(head->ht[h]); f;
 376                      f = rtnl_dereference(f->next)) {
 377                         if (arg->count < arg->skip) {
 378                                 arg->count++;
 379                                 continue;
 380                         }
 381                         if (arg->fn(tp, f, arg) < 0) {
 382                                 arg->stop = 1;
 383                                 return;
 384                         }
 385                         arg->count++;
 386                 }
 387         }
 388 }
 389
 390 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 391                    struct sk_buff *skb, struct tcmsg *t)
 392 {
 393         struct fw_head *head = rtnl_dereference(tp->root);
 394         struct fw_filter *f = fh;
 395         struct nlattr *nest;
 396
 397         if (f == NULL)
 398                 return skb->len;
 399
 400         t->tcm_handle = f->id;
 401
 402         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 403                 return skb->len;
 404
 405         nest = nla_nest_start(skb, TCA_OPTIONS);
 406         if (nest == NULL)
 407                 goto nla_put_failure;
 408
 409         if (f->res.classid &&
 410             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 411                 goto nla_put_failure;
 412 #ifdef CONFIG_NET_CLS_IND
 413         if (f->ifindex) {
 414                 struct net_device *dev;
 415                 dev = __dev_get_by_index(net, f->ifindex);
 416                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 417                         goto nla_put_failure;
 418         }
 419 #endif /* CONFIG_NET_CLS_IND */
 420         if (head->mask != 0xFFFFFFFF &&
 421             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 422                 goto nla_put_failure;
 423
 424         if (tcf_exts_dump(skb, &f->exts) < 0)
 425                 goto nla_put_failure;
 426
 427         nla_nest_end(skb, nest);
 428
 429         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 430                 goto nla_put_failure;
 431
 432         return skb->len;
 433
 434 nla_put_failure:
 435         nla_nest_cancel(skb, nest);
 436         return -1;
 437 }
 438
 439 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 440 {
 441         struct fw_filter *f = fh;
 442
 443         if (f && f->res.classid == classid)
 444                 f->res.class = cl;
 445 }
 446
 447 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 448         .kind           =       "fw",
 449         .classify       =       fw_classify,
 450         .init           =       fw_init,
 451         .destroy        =       fw_destroy,
 452         .get            =       fw_get,
 453         .change         =       fw_change,
 454         .delete         =       fw_delete,
 455         .walk           =       fw_walk,
 456         .dump           =       fw_dump,
 457         .bind_class     =       fw_bind_class,
 458         .owner          =       THIS_MODULE,
 459 };
 460
 461 static int __init init_fw(void)
 462 {
 463         return register_tcf_proto_ops(&cls_fw_ops);
 464 }
 465
 466 static void __exit exit_fw(void)
 467 {
 468         unregister_tcf_proto_ops(&cls_fw_ops);
 469 }
 470
 471 module_init(init_fw)
 472 module_exit(exit_fw)
 473 MODULE_LICENSE("GPL");