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_work(struct work_struct *work)
 126 {
 127         struct fw_filter *f = container_of(work, struct fw_filter, work);
 128
 129         rtnl_lock();
 130         tcf_exts_destroy(&f->exts);
 131         kfree(f);
 132         rtnl_unlock();
 133 }
 134
 135 static void fw_delete_filter(struct rcu_head *head)
 136 {
 137         struct fw_filter *f = container_of(head, struct fw_filter, rcu);
 138
 139         INIT_WORK(&f->work, fw_delete_filter_work);
 140         tcf_queue_work(&f->work);
 141 }
 142
 143 static void fw_destroy(struct tcf_proto *tp)
 144 {
 145         struct fw_head *head = rtnl_dereference(tp->root);
 146         struct fw_filter *f;
 147         int h;
 148
 149         if (head == NULL)
 150                 return;
 151
 152         for (h = 0; h < HTSIZE; h++) {
 153                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 154                         RCU_INIT_POINTER(head->ht[h],
 155                                          rtnl_dereference(f->next));
 156                         tcf_unbind_filter(tp, &f->res);
 157                         call_rcu(&f->rcu, fw_delete_filter);
 158                 }
 159         }
 160         kfree_rcu(head, rcu);
 161 }
 162
 163 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
 164 {
 165         struct fw_head *head = rtnl_dereference(tp->root);
 166         struct fw_filter *f = arg;
 167         struct fw_filter __rcu **fp;
 168         struct fw_filter *pfp;
 169         int ret = -EINVAL;
 170         int h;
 171
 172         if (head == NULL || f == NULL)
 173                 goto out;
 174
 175         fp = &head->ht[fw_hash(f->id)];
 176
 177         for (pfp = rtnl_dereference(*fp); pfp;
 178              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 179                 if (pfp == f) {
 180                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 181                         tcf_unbind_filter(tp, &f->res);
 182                         call_rcu(&f->rcu, fw_delete_filter);
 183                         ret = 0;
 184                         break;
 185                 }
 186         }
 187
 188         *last = true;
 189         for (h = 0; h < HTSIZE; h++) {
 190                 if (rcu_access_pointer(head->ht[h])) {
 191                         *last = false;
 192                         break;
 193                 }
 194         }
 195
 196 out:
 197         return ret;
 198 }
 199
 200 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 201         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 202         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 203         [TCA_FW_MASK]           = { .type = NLA_U32 },
 204 };
 205
 206 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 207                         struct fw_filter *f, struct nlattr **tb,
 208                         struct nlattr **tca, unsigned long base, bool ovr)
 209 {
 210         struct fw_head *head = rtnl_dereference(tp->root);
 211         u32 mask;
 212         int err;
 213
 214         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
 215         if (err < 0)
 216                 return err;
 217
 218         if (tb[TCA_FW_CLASSID]) {
 219                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 220                 tcf_bind_filter(tp, &f->res, base);
 221         }
 222
 223 #ifdef CONFIG_NET_CLS_IND
 224         if (tb[TCA_FW_INDEV]) {
 225                 int ret;
 226                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 227                 if (ret < 0)
 228                         return ret;
 229                 f->ifindex = ret;
 230         }
 231 #endif /* CONFIG_NET_CLS_IND */
 232
 233         err = -EINVAL;
 234         if (tb[TCA_FW_MASK]) {
 235                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 236                 if (mask != head->mask)
 237                         return err;
 238         } else if (head->mask != 0xFFFFFFFF)
 239                 return err;
 240
 241         return 0;
 242 }
 243
 244 static int fw_change(struct net *net, struct sk_buff *in_skb,
 245                      struct tcf_proto *tp, unsigned long base,
 246                      u32 handle, struct nlattr **tca, void **arg,
 247                      bool ovr)
 248 {
 249         struct fw_head *head = rtnl_dereference(tp->root);
 250         struct fw_filter *f = *arg;
 251         struct nlattr *opt = tca[TCA_OPTIONS];
 252         struct nlattr *tb[TCA_FW_MAX + 1];
 253         int err;
 254
 255         if (!opt)
 256                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 257
 258         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 259         if (err < 0)
 260                 return err;
 261
 262         if (f) {
 263                 struct fw_filter *pfp, *fnew;
 264                 struct fw_filter __rcu **fp;
 265
 266                 if (f->id != handle && handle)
 267                         return -EINVAL;
 268
 269                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 270                 if (!fnew)
 271                         return -ENOBUFS;
 272
 273                 fnew->id = f->id;
 274                 fnew->res = f->res;
 275 #ifdef CONFIG_NET_CLS_IND
 276                 fnew->ifindex = f->ifindex;
 277 #endif /* CONFIG_NET_CLS_IND */
 278                 fnew->tp = f->tp;
 279
 280                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 281                 if (err < 0) {
 282                         kfree(fnew);
 283                         return err;
 284                 }
 285
 286                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
 287                 if (err < 0) {
 288                         tcf_exts_destroy(&fnew->exts);
 289                         kfree(fnew);
 290                         return err;
 291                 }
 292
 293                 fp = &head->ht[fw_hash(fnew->id)];
 294                 for (pfp = rtnl_dereference(*fp); pfp;
 295                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 296                         if (pfp == f)
 297                                 break;
 298
 299                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 300                 rcu_assign_pointer(*fp, fnew);
 301                 tcf_unbind_filter(tp, &f->res);
 302                 call_rcu(&f->rcu, fw_delete_filter);
 303
 304                 *arg = fnew;
 305                 return err;
 306         }
 307
 308         if (!handle)
 309                 return -EINVAL;
 310
 311         if (!head) {
 312                 u32 mask = 0xFFFFFFFF;
 313                 if (tb[TCA_FW_MASK])
 314                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 315
 316                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 317                 if (!head)
 318                         return -ENOBUFS;
 319                 head->mask = mask;
 320
 321                 rcu_assign_pointer(tp->root, head);
 322         }
 323
 324         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 325         if (f == NULL)
 326                 return -ENOBUFS;
 327
 328         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 329         if (err < 0)
 330                 goto errout;
 331         f->id = handle;
 332         f->tp = tp;
 333
 334         err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
 335         if (err < 0)
 336                 goto errout;
 337
 338         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 339         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 340
 341         *arg = f;
 342         return 0;
 343
 344 errout:
 345         tcf_exts_destroy(&f->exts);
 346         kfree(f);
 347         return err;
 348 }
 349
 350 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 351 {
 352         struct fw_head *head = rtnl_dereference(tp->root);
 353         int h;
 354
 355         if (head == NULL)
 356                 arg->stop = 1;
 357
 358         if (arg->stop)
 359                 return;
 360
 361         for (h = 0; h < HTSIZE; h++) {
 362                 struct fw_filter *f;
 363
 364                 for (f = rtnl_dereference(head->ht[h]); f;
 365                      f = rtnl_dereference(f->next)) {
 366                         if (arg->count < arg->skip) {
 367                                 arg->count++;
 368                                 continue;
 369                         }
 370                         if (arg->fn(tp, f, arg) < 0) {
 371                                 arg->stop = 1;
 372                                 return;
 373                         }
 374                         arg->count++;
 375                 }
 376         }
 377 }
 378
 379 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 380                    struct sk_buff *skb, struct tcmsg *t)
 381 {
 382         struct fw_head *head = rtnl_dereference(tp->root);
 383         struct fw_filter *f = fh;
 384         struct nlattr *nest;
 385
 386         if (f == NULL)
 387                 return skb->len;
 388
 389         t->tcm_handle = f->id;
 390
 391         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 392                 return skb->len;
 393
 394         nest = nla_nest_start(skb, TCA_OPTIONS);
 395         if (nest == NULL)
 396                 goto nla_put_failure;
 397
 398         if (f->res.classid &&
 399             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 400                 goto nla_put_failure;
 401 #ifdef CONFIG_NET_CLS_IND
 402         if (f->ifindex) {
 403                 struct net_device *dev;
 404                 dev = __dev_get_by_index(net, f->ifindex);
 405                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 406                         goto nla_put_failure;
 407         }
 408 #endif /* CONFIG_NET_CLS_IND */
 409         if (head->mask != 0xFFFFFFFF &&
 410             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 411                 goto nla_put_failure;
 412
 413         if (tcf_exts_dump(skb, &f->exts) < 0)
 414                 goto nla_put_failure;
 415
 416         nla_nest_end(skb, nest);
 417
 418         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 419                 goto nla_put_failure;
 420
 421         return skb->len;
 422
 423 nla_put_failure:
 424         nla_nest_cancel(skb, nest);
 425         return -1;
 426 }
 427
 428 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 429 {
 430         struct fw_filter *f = fh;
 431
 432         if (f && f->res.classid == classid)
 433                 f->res.class = cl;
 434 }
 435
 436 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 437         .kind           =       "fw",
 438         .classify       =       fw_classify,
 439         .init           =       fw_init,
 440         .destroy        =       fw_destroy,
 441         .get            =       fw_get,
 442         .change         =       fw_change,
 443         .delete         =       fw_delete,
 444         .walk           =       fw_walk,
 445         .dump           =       fw_dump,
 446         .bind_class     =       fw_bind_class,
 447         .owner          =       THIS_MODULE,
 448 };
 449
 450 static int __init init_fw(void)
 451 {
 452         return register_tcf_proto_ops(&cls_fw_ops);
 453 }
 454
 455 static void __exit exit_fw(void)
 456 {
 457         unregister_tcf_proto_ops(&cls_fw_ops);
 458 }
 459
 460 module_init(init_fw)
 461 module_exit(exit_fw)
 462 MODULE_LICENSE("GPL");