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