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 #include <net/sch_generic.h>
  32
  33 #define HTSIZE 256
  34
  35 struct fw_head {
  36         u32                     mask;
  37         struct fw_filter __rcu  *ht[HTSIZE];
  38         struct rcu_head         rcu;
  39 };
  40
  41 struct fw_filter {
  42         struct fw_filter __rcu  *next;
  43         u32                     id;
  44         struct tcf_result       res;
  45 #ifdef CONFIG_NET_CLS_IND
  46         int                     ifindex;
  47 #endif /* CONFIG_NET_CLS_IND */
  48         struct tcf_exts         exts;
  49         struct tcf_proto        *tp;
  50         struct rcu_head         rcu;
  51 };
  52
  53 static u32 fw_hash(u32 handle)
  54 {
  55         handle ^= (handle >> 16);
  56         handle ^= (handle >> 8);
  57         return handle % HTSIZE;
  58 }
  59
  60 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  61                        struct tcf_result *res)
  62 {
  63         struct fw_head *head = rcu_dereference_bh(tp->root);
  64         struct fw_filter *f;
  65         int r;
  66         u32 id = skb->mark;
  67
  68         if (head != NULL) {
  69                 id &= head->mask;
  70
  71                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  72                      f = rcu_dereference_bh(f->next)) {
  73                         if (f->id == id) {
  74                                 *res = f->res;
  75 #ifdef CONFIG_NET_CLS_IND
  76                                 if (!tcf_match_indev(skb, f->ifindex))
  77                                         continue;
  78 #endif /* CONFIG_NET_CLS_IND */
  79                                 r = tcf_exts_exec(skb, &f->exts, res);
  80                                 if (r < 0)
  81                                         continue;
  82
  83                                 return r;
  84                         }
  85                 }
  86         } else {
  87                 struct Qdisc *q = tcf_block_q(tp->chain->block);
  88
  89                 /* Old method: classify the packet using its skb mark. */
  90                 if (id && (TC_H_MAJ(id) == 0 ||
  91                            !(TC_H_MAJ(id ^ 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 rcu_head *head)
 126 {
 127         struct fw_filter *f = container_of(head, struct fw_filter, rcu);
 128
 129         tcf_exts_destroy(&f->exts);
 130         kfree(f);
 131 }
 132
 133 static void fw_destroy(struct tcf_proto *tp)
 134 {
 135         struct fw_head *head = rtnl_dereference(tp->root);
 136         struct fw_filter *f;
 137         int h;
 138
 139         if (head == NULL)
 140                 return;
 141
 142         for (h = 0; h < HTSIZE; h++) {
 143                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 144                         RCU_INIT_POINTER(head->ht[h],
 145                                          rtnl_dereference(f->next));
 146                         tcf_unbind_filter(tp, &f->res);
 147                         call_rcu(&f->rcu, fw_delete_filter);
 148                 }
 149         }
 150         kfree_rcu(head, rcu);
 151 }
 152
 153 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
 154 {
 155         struct fw_head *head = rtnl_dereference(tp->root);
 156         struct fw_filter *f = arg;
 157         struct fw_filter __rcu **fp;
 158         struct fw_filter *pfp;
 159         int ret = -EINVAL;
 160         int h;
 161
 162         if (head == NULL || f == NULL)
 163                 goto out;
 164
 165         fp = &head->ht[fw_hash(f->id)];
 166
 167         for (pfp = rtnl_dereference(*fp); pfp;
 168              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 169                 if (pfp == f) {
 170                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 171                         tcf_unbind_filter(tp, &f->res);
 172                         call_rcu(&f->rcu, fw_delete_filter);
 173                         ret = 0;
 174                         break;
 175                 }
 176         }
 177
 178         *last = true;
 179         for (h = 0; h < HTSIZE; h++) {
 180                 if (rcu_access_pointer(head->ht[h])) {
 181                         *last = false;
 182                         break;
 183                 }
 184         }
 185
 186 out:
 187         return ret;
 188 }
 189
 190 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 191         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 192         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 193         [TCA_FW_MASK]           = { .type = NLA_U32 },
 194 };
 195
 196 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 197                         struct fw_filter *f, struct nlattr **tb,
 198                         struct nlattr **tca, unsigned long base, bool ovr)
 199 {
 200         struct fw_head *head = rtnl_dereference(tp->root);
 201         u32 mask;
 202         int err;
 203
 204         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
 205         if (err < 0)
 206                 return err;
 207
 208         if (tb[TCA_FW_CLASSID]) {
 209                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 210                 tcf_bind_filter(tp, &f->res, base);
 211         }
 212
 213 #ifdef CONFIG_NET_CLS_IND
 214         if (tb[TCA_FW_INDEV]) {
 215                 int ret;
 216                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
 217                 if (ret < 0)
 218                         return ret;
 219                 f->ifindex = ret;
 220         }
 221 #endif /* CONFIG_NET_CLS_IND */
 222
 223         err = -EINVAL;
 224         if (tb[TCA_FW_MASK]) {
 225                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 226                 if (mask != head->mask)
 227                         return err;
 228         } else if (head->mask != 0xFFFFFFFF)
 229                 return err;
 230
 231         return 0;
 232 }
 233
 234 static int fw_change(struct net *net, struct sk_buff *in_skb,
 235                      struct tcf_proto *tp, unsigned long base,
 236                      u32 handle, struct nlattr **tca, void **arg,
 237                      bool ovr)
 238 {
 239         struct fw_head *head = rtnl_dereference(tp->root);
 240         struct fw_filter *f = *arg;
 241         struct nlattr *opt = tca[TCA_OPTIONS];
 242         struct nlattr *tb[TCA_FW_MAX + 1];
 243         int err;
 244
 245         if (!opt)
 246                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 247
 248         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 249         if (err < 0)
 250                 return err;
 251
 252         if (f) {
 253                 struct fw_filter *pfp, *fnew;
 254                 struct fw_filter __rcu **fp;
 255
 256                 if (f->id != handle && handle)
 257                         return -EINVAL;
 258
 259                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 260                 if (!fnew)
 261                         return -ENOBUFS;
 262
 263                 fnew->id = f->id;
 264                 fnew->res = f->res;
 265 #ifdef CONFIG_NET_CLS_IND
 266                 fnew->ifindex = f->ifindex;
 267 #endif /* CONFIG_NET_CLS_IND */
 268                 fnew->tp = f->tp;
 269
 270                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 271                 if (err < 0) {
 272                         kfree(fnew);
 273                         return err;
 274                 }
 275
 276                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
 277                 if (err < 0) {
 278                         tcf_exts_destroy(&fnew->exts);
 279                         kfree(fnew);
 280                         return err;
 281                 }
 282
 283                 fp = &head->ht[fw_hash(fnew->id)];
 284                 for (pfp = rtnl_dereference(*fp); pfp;
 285                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 286                         if (pfp == f)
 287                                 break;
 288
 289                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 290                 rcu_assign_pointer(*fp, fnew);
 291                 tcf_unbind_filter(tp, &f->res);
 292                 call_rcu(&f->rcu, fw_delete_filter);
 293
 294                 *arg = fnew;
 295                 return err;
 296         }
 297
 298         if (!handle)
 299                 return -EINVAL;
 300
 301         if (!head) {
 302                 u32 mask = 0xFFFFFFFF;
 303                 if (tb[TCA_FW_MASK])
 304                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 305
 306                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 307                 if (!head)
 308                         return -ENOBUFS;
 309                 head->mask = mask;
 310
 311                 rcu_assign_pointer(tp->root, head);
 312         }
 313
 314         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 315         if (f == NULL)
 316                 return -ENOBUFS;
 317
 318         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 319         if (err < 0)
 320                 goto errout;
 321         f->id = handle;
 322         f->tp = tp;
 323
 324         err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
 325         if (err < 0)
 326                 goto errout;
 327
 328         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 329         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 330
 331         *arg = f;
 332         return 0;
 333
 334 errout:
 335         tcf_exts_destroy(&f->exts);
 336         kfree(f);
 337         return err;
 338 }
 339
 340 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 341 {
 342         struct fw_head *head = rtnl_dereference(tp->root);
 343         int h;
 344
 345         if (head == NULL)
 346                 arg->stop = 1;
 347
 348         if (arg->stop)
 349                 return;
 350
 351         for (h = 0; h < HTSIZE; h++) {
 352                 struct fw_filter *f;
 353
 354                 for (f = rtnl_dereference(head->ht[h]); f;
 355                      f = rtnl_dereference(f->next)) {
 356                         if (arg->count < arg->skip) {
 357                                 arg->count++;
 358                                 continue;
 359                         }
 360                         if (arg->fn(tp, f, arg) < 0) {
 361                                 arg->stop = 1;
 362                                 return;
 363                         }
 364                         arg->count++;
 365                 }
 366         }
 367 }
 368
 369 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 370                    struct sk_buff *skb, struct tcmsg *t)
 371 {
 372         struct fw_head *head = rtnl_dereference(tp->root);
 373         struct fw_filter *f = fh;
 374         struct nlattr *nest;
 375
 376         if (f == NULL)
 377                 return skb->len;
 378
 379         t->tcm_handle = f->id;
 380
 381         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 382                 return skb->len;
 383
 384         nest = nla_nest_start(skb, TCA_OPTIONS);
 385         if (nest == NULL)
 386                 goto nla_put_failure;
 387
 388         if (f->res.classid &&
 389             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 390                 goto nla_put_failure;
 391 #ifdef CONFIG_NET_CLS_IND
 392         if (f->ifindex) {
 393                 struct net_device *dev;
 394                 dev = __dev_get_by_index(net, f->ifindex);
 395                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 396                         goto nla_put_failure;
 397         }
 398 #endif /* CONFIG_NET_CLS_IND */
 399         if (head->mask != 0xFFFFFFFF &&
 400             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 401                 goto nla_put_failure;
 402
 403         if (tcf_exts_dump(skb, &f->exts) < 0)
 404                 goto nla_put_failure;
 405
 406         nla_nest_end(skb, nest);
 407
 408         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 409                 goto nla_put_failure;
 410
 411         return skb->len;
 412
 413 nla_put_failure:
 414         nla_nest_cancel(skb, nest);
 415         return -1;
 416 }
 417
 418 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 419 {
 420         struct fw_filter *f = fh;
 421
 422         if (f && f->res.classid == classid)
 423                 f->res.class = cl;
 424 }
 425
 426 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 427         .kind           =       "fw",
 428         .classify       =       fw_classify,
 429         .init           =       fw_init,
 430         .destroy        =       fw_destroy,
 431         .get            =       fw_get,
 432         .change         =       fw_change,
 433         .delete         =       fw_delete,
 434         .walk           =       fw_walk,
 435         .dump           =       fw_dump,
 436         .bind_class     =       fw_bind_class,
 437         .owner          =       THIS_MODULE,
 438 };
 439
 440 static int __init init_fw(void)
 441 {
 442         return register_tcf_proto_ops(&cls_fw_ops);
 443 }
 444
 445 static void __exit exit_fw(void)
 446 {
 447         unregister_tcf_proto_ops(&cls_fw_ops);
 448 }
 449
 450 module_init(init_fw)
 451 module_exit(exit_fw)
 452 MODULE_LICENSE("GPL");