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 void *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 NULL;
 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 f;
 110         }
 111         return NULL;
 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 void fw_destroy(struct tcf_proto *tp)
 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;
 138
 139         for (h = 0; h < HTSIZE; h++) {
 140                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 141                         RCU_INIT_POINTER(head->ht[h],
 142                                          rtnl_dereference(f->next));
 143                         tcf_unbind_filter(tp, &f->res);
 144                         call_rcu(&f->rcu, fw_delete_filter);
 145                 }
 146         }
 147         kfree_rcu(head, rcu);
 148 }
 149
 150 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
 151 {
 152         struct fw_head *head = rtnl_dereference(tp->root);
 153         struct fw_filter *f = arg;
 154         struct fw_filter __rcu **fp;
 155         struct fw_filter *pfp;
 156         int ret = -EINVAL;
 157         int h;
 158
 159         if (head == NULL || f == NULL)
 160                 goto out;
 161
 162         fp = &head->ht[fw_hash(f->id)];
 163
 164         for (pfp = rtnl_dereference(*fp); pfp;
 165              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 166                 if (pfp == f) {
 167                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 168                         tcf_unbind_filter(tp, &f->res);
 169                         call_rcu(&f->rcu, fw_delete_filter);
 170                         ret = 0;
 171                         break;
 172                 }
 173         }
 174
 175         *last = true;
 176         for (h = 0; h < HTSIZE; h++) {
 177                 if (rcu_access_pointer(head->ht[h])) {
 178                         *last = false;
 179                         break;
 180                 }
 181         }
 182
 183 out:
 184         return ret;
 185 }
 186
 187 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 188         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 189         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 190         [TCA_FW_MASK]           = { .type = NLA_U32 },
 191 };
 192
 193 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 194                         struct fw_filter *f, struct nlattr **tb,
 195                         struct nlattr **tca, unsigned long base, bool ovr)
 196 {
 197         struct fw_head *head = rtnl_dereference(tp->root);
 198         u32 mask;
 199         int err;
 200
 201         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
 202         if (err < 0)
 203                 return err;
 204
 205         if (tb[TCA_FW_CLASSID]) {
 206                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 207                 tcf_bind_filter(tp, &f->res, base);
 208         }
 209
 210 #ifdef CONFIG_NET_CLS_IND
 211         if (tb[TCA_FW_INDEV]) {
 212                 int ret;
 213                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 214                 if (ret < 0)
 215                         return ret;
 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                         return err;
 225         } else if (head->mask != 0xFFFFFFFF)
 226                 return err;
 227
 228         return 0;
 229 }
 230
 231 static int fw_change(struct net *net, struct sk_buff *in_skb,
 232                      struct tcf_proto *tp, unsigned long base,
 233                      u32 handle, struct nlattr **tca, void **arg,
 234                      bool ovr)
 235 {
 236         struct fw_head *head = rtnl_dereference(tp->root);
 237         struct fw_filter *f = *arg;
 238         struct nlattr *opt = tca[TCA_OPTIONS];
 239         struct nlattr *tb[TCA_FW_MAX + 1];
 240         int err;
 241
 242         if (!opt)
 243                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 244
 245         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 246         if (err < 0)
 247                 return err;
 248
 249         if (f) {
 250                 struct fw_filter *pfp, *fnew;
 251                 struct fw_filter __rcu **fp;
 252
 253                 if (f->id != handle && handle)
 254                         return -EINVAL;
 255
 256                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 257                 if (!fnew)
 258                         return -ENOBUFS;
 259
 260                 fnew->id = f->id;
 261                 fnew->res = f->res;
 262 #ifdef CONFIG_NET_CLS_IND
 263                 fnew->ifindex = f->ifindex;
 264 #endif /* CONFIG_NET_CLS_IND */
 265                 fnew->tp = f->tp;
 266
 267                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 268                 if (err < 0) {
 269                         kfree(fnew);
 270                         return err;
 271                 }
 272
 273                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
 274                 if (err < 0) {
 275                         tcf_exts_destroy(&fnew->exts);
 276                         kfree(fnew);
 277                         return err;
 278                 }
 279
 280                 fp = &head->ht[fw_hash(fnew->id)];
 281                 for (pfp = rtnl_dereference(*fp); pfp;
 282                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 283                         if (pfp == f)
 284                                 break;
 285
 286                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 287                 rcu_assign_pointer(*fp, fnew);
 288                 tcf_unbind_filter(tp, &f->res);
 289                 call_rcu(&f->rcu, fw_delete_filter);
 290
 291                 *arg = fnew;
 292                 return err;
 293         }
 294
 295         if (!handle)
 296                 return -EINVAL;
 297
 298         if (!head) {
 299                 u32 mask = 0xFFFFFFFF;
 300                 if (tb[TCA_FW_MASK])
 301                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 302
 303                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 304                 if (!head)
 305                         return -ENOBUFS;
 306                 head->mask = mask;
 307
 308                 rcu_assign_pointer(tp->root, head);
 309         }
 310
 311         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 312         if (f == NULL)
 313                 return -ENOBUFS;
 314
 315         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 316         if (err < 0)
 317                 goto errout;
 318         f->id = handle;
 319         f->tp = tp;
 320
 321         err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
 322         if (err < 0)
 323                 goto errout;
 324
 325         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 326         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 327
 328         *arg = f;
 329         return 0;
 330
 331 errout:
 332         tcf_exts_destroy(&f->exts);
 333         kfree(f);
 334         return err;
 335 }
 336
 337 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 338 {
 339         struct fw_head *head = rtnl_dereference(tp->root);
 340         int h;
 341
 342         if (head == NULL)
 343                 arg->stop = 1;
 344
 345         if (arg->stop)
 346                 return;
 347
 348         for (h = 0; h < HTSIZE; h++) {
 349                 struct fw_filter *f;
 350
 351                 for (f = rtnl_dereference(head->ht[h]); f;
 352                      f = rtnl_dereference(f->next)) {
 353                         if (arg->count < arg->skip) {
 354                                 arg->count++;
 355                                 continue;
 356                         }
 357                         if (arg->fn(tp, f, arg) < 0) {
 358                                 arg->stop = 1;
 359                                 return;
 360                         }
 361                         arg->count++;
 362                 }
 363         }
 364 }
 365
 366 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 367                    struct sk_buff *skb, struct tcmsg *t)
 368 {
 369         struct fw_head *head = rtnl_dereference(tp->root);
 370         struct fw_filter *f = fh;
 371         struct nlattr *nest;
 372
 373         if (f == NULL)
 374                 return skb->len;
 375
 376         t->tcm_handle = f->id;
 377
 378         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 379                 return skb->len;
 380
 381         nest = nla_nest_start(skb, TCA_OPTIONS);
 382         if (nest == NULL)
 383                 goto nla_put_failure;
 384
 385         if (f->res.classid &&
 386             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 387                 goto nla_put_failure;
 388 #ifdef CONFIG_NET_CLS_IND
 389         if (f->ifindex) {
 390                 struct net_device *dev;
 391                 dev = __dev_get_by_index(net, f->ifindex);
 392                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 393                         goto nla_put_failure;
 394         }
 395 #endif /* CONFIG_NET_CLS_IND */
 396         if (head->mask != 0xFFFFFFFF &&
 397             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 398                 goto nla_put_failure;
 399
 400         if (tcf_exts_dump(skb, &f->exts) < 0)
 401                 goto nla_put_failure;
 402
 403         nla_nest_end(skb, nest);
 404
 405         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 406                 goto nla_put_failure;
 407
 408         return skb->len;
 409
 410 nla_put_failure:
 411         nla_nest_cancel(skb, nest);
 412         return -1;
 413 }
 414
 415 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 416 {
 417         struct fw_filter *f = fh;
 418
 419         if (f && f->res.classid == classid)
 420                 f->res.class = cl;
 421 }
 422
 423 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 424         .kind           =       "fw",
 425         .classify       =       fw_classify,
 426         .init           =       fw_init,
 427         .destroy        =       fw_destroy,
 428         .get            =       fw_get,
 429         .change         =       fw_change,
 430         .delete         =       fw_delete,
 431         .walk           =       fw_walk,
 432         .dump           =       fw_dump,
 433         .bind_class     =       fw_bind_class,
 434         .owner          =       THIS_MODULE,
 435 };
 436
 437 static int __init init_fw(void)
 438 {
 439         return register_tcf_proto_ops(&cls_fw_ops);
 440 }
 441
 442 static void __exit exit_fw(void)
 443 {
 444         unregister_tcf_proto_ops(&cls_fw_ops);
 445 }
 446
 447 module_init(init_fw)
 448 module_exit(exit_fw)
 449 MODULE_LICENSE("GPL");