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_work         rwork;
  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 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(to_rcu_work(work),
 135                                            struct fw_filter,
 136                                            rwork);
 137         rtnl_lock();
 138         __fw_delete_filter(f);
 139         rtnl_unlock();
 140 }
 141
 142 static void fw_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 143 {
 144         struct fw_head *head = rtnl_dereference(tp->root);
 145         struct fw_filter *f;
 146         int h;
 147
 148         if (head == NULL)
 149                 return;
 150
 151         for (h = 0; h < HTSIZE; h++) {
 152                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 153                         RCU_INIT_POINTER(head->ht[h],
 154                                          rtnl_dereference(f->next));
 155                         tcf_unbind_filter(tp, &f->res);
 156                         if (tcf_exts_get_net(&f->exts))
 157                                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 158                         else
 159                                 __fw_delete_filter(f);
 160                 }
 161         }
 162         kfree_rcu(head, rcu);
 163 }
 164
 165 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
 166                      struct netlink_ext_ack *extack)
 167 {
 168         struct fw_head *head = rtnl_dereference(tp->root);
 169         struct fw_filter *f = arg;
 170         struct fw_filter __rcu **fp;
 171         struct fw_filter *pfp;
 172         int ret = -EINVAL;
 173         int h;
 174
 175         if (head == NULL || f == NULL)
 176                 goto out;
 177
 178         fp = &head->ht[fw_hash(f->id)];
 179
 180         for (pfp = rtnl_dereference(*fp); pfp;
 181              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 182                 if (pfp == f) {
 183                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 184                         tcf_unbind_filter(tp, &f->res);
 185                         tcf_exts_get_net(&f->exts);
 186                         tcf_queue_work(&f->rwork, fw_delete_filter_work);
 187                         ret = 0;
 188                         break;
 189                 }
 190         }
 191
 192         *last = true;
 193         for (h = 0; h < HTSIZE; h++) {
 194                 if (rcu_access_pointer(head->ht[h])) {
 195                         *last = false;
 196                         break;
 197                 }
 198         }
 199
 200 out:
 201         return ret;
 202 }
 203
 204 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 205         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 206         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 207         [TCA_FW_MASK]           = { .type = NLA_U32 },
 208 };
 209
 210 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 211                         struct fw_filter *f, struct nlattr **tb,
 212                         struct nlattr **tca, unsigned long base, bool ovr,
 213                         struct netlink_ext_ack *extack)
 214 {
 215         struct fw_head *head = rtnl_dereference(tp->root);
 216         u32 mask;
 217         int err;
 218
 219         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
 220                                 extack);
 221         if (err < 0)
 222                 return err;
 223
 224         if (tb[TCA_FW_CLASSID]) {
 225                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 226                 tcf_bind_filter(tp, &f->res, base);
 227         }
 228
 229 #ifdef CONFIG_NET_CLS_IND
 230         if (tb[TCA_FW_INDEV]) {
 231                 int ret;
 232                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
 233                 if (ret < 0)
 234                         return ret;
 235                 f->ifindex = ret;
 236         }
 237 #endif /* CONFIG_NET_CLS_IND */
 238
 239         err = -EINVAL;
 240         if (tb[TCA_FW_MASK]) {
 241                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 242                 if (mask != head->mask)
 243                         return err;
 244         } else if (head->mask != 0xFFFFFFFF)
 245                 return err;
 246
 247         return 0;
 248 }
 249
 250 static int fw_change(struct net *net, struct sk_buff *in_skb,
 251                      struct tcf_proto *tp, unsigned long base,
 252                      u32 handle, struct nlattr **tca, void **arg,
 253                      bool ovr, struct netlink_ext_ack *extack)
 254 {
 255         struct fw_head *head = rtnl_dereference(tp->root);
 256         struct fw_filter *f = *arg;
 257         struct nlattr *opt = tca[TCA_OPTIONS];
 258         struct nlattr *tb[TCA_FW_MAX + 1];
 259         int err;
 260
 261         if (!opt)
 262                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 263
 264         err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
 265         if (err < 0)
 266                 return err;
 267
 268         if (f) {
 269                 struct fw_filter *pfp, *fnew;
 270                 struct fw_filter __rcu **fp;
 271
 272                 if (f->id != handle && handle)
 273                         return -EINVAL;
 274
 275                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 276                 if (!fnew)
 277                         return -ENOBUFS;
 278
 279                 fnew->id = f->id;
 280                 fnew->res = f->res;
 281 #ifdef CONFIG_NET_CLS_IND
 282                 fnew->ifindex = f->ifindex;
 283 #endif /* CONFIG_NET_CLS_IND */
 284                 fnew->tp = f->tp;
 285
 286                 err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
 287                 if (err < 0) {
 288                         kfree(fnew);
 289                         return err;
 290                 }
 291
 292                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
 293                 if (err < 0) {
 294                         tcf_exts_destroy(&fnew->exts);
 295                         kfree(fnew);
 296                         return err;
 297                 }
 298
 299                 fp = &head->ht[fw_hash(fnew->id)];
 300                 for (pfp = rtnl_dereference(*fp); pfp;
 301                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 302                         if (pfp == f)
 303                                 break;
 304
 305                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 306                 rcu_assign_pointer(*fp, fnew);
 307                 tcf_unbind_filter(tp, &f->res);
 308                 tcf_exts_get_net(&f->exts);
 309                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 310
 311                 *arg = fnew;
 312                 return err;
 313         }
 314
 315         if (!handle)
 316                 return -EINVAL;
 317
 318         if (!head) {
 319                 u32 mask = 0xFFFFFFFF;
 320                 if (tb[TCA_FW_MASK])
 321                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 322
 323                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 324                 if (!head)
 325                         return -ENOBUFS;
 326                 head->mask = mask;
 327
 328                 rcu_assign_pointer(tp->root, head);
 329         }
 330
 331         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 332         if (f == NULL)
 333                 return -ENOBUFS;
 334
 335         err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
 336         if (err < 0)
 337                 goto errout;
 338         f->id = handle;
 339         f->tp = tp;
 340
 341         err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
 342         if (err < 0)
 343                 goto errout;
 344
 345         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 346         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 347
 348         *arg = f;
 349         return 0;
 350
 351 errout:
 352         tcf_exts_destroy(&f->exts);
 353         kfree(f);
 354         return err;
 355 }
 356
 357 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 358 {
 359         struct fw_head *head = rtnl_dereference(tp->root);
 360         int h;
 361
 362         if (head == NULL)
 363                 arg->stop = 1;
 364
 365         if (arg->stop)
 366                 return;
 367
 368         for (h = 0; h < HTSIZE; h++) {
 369                 struct fw_filter *f;
 370
 371                 for (f = rtnl_dereference(head->ht[h]); f;
 372                      f = rtnl_dereference(f->next)) {
 373                         if (arg->count < arg->skip) {
 374                                 arg->count++;
 375                                 continue;
 376                         }
 377                         if (arg->fn(tp, f, arg) < 0) {
 378                                 arg->stop = 1;
 379                                 return;
 380                         }
 381                         arg->count++;
 382                 }
 383         }
 384 }
 385
 386 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 387                    struct sk_buff *skb, struct tcmsg *t)
 388 {
 389         struct fw_head *head = rtnl_dereference(tp->root);
 390         struct fw_filter *f = fh;
 391         struct nlattr *nest;
 392
 393         if (f == NULL)
 394                 return skb->len;
 395
 396         t->tcm_handle = f->id;
 397
 398         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 399                 return skb->len;
 400
 401         nest = nla_nest_start(skb, TCA_OPTIONS);
 402         if (nest == NULL)
 403                 goto nla_put_failure;
 404
 405         if (f->res.classid &&
 406             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 407                 goto nla_put_failure;
 408 #ifdef CONFIG_NET_CLS_IND
 409         if (f->ifindex) {
 410                 struct net_device *dev;
 411                 dev = __dev_get_by_index(net, f->ifindex);
 412                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 413                         goto nla_put_failure;
 414         }
 415 #endif /* CONFIG_NET_CLS_IND */
 416         if (head->mask != 0xFFFFFFFF &&
 417             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 418                 goto nla_put_failure;
 419
 420         if (tcf_exts_dump(skb, &f->exts) < 0)
 421                 goto nla_put_failure;
 422
 423         nla_nest_end(skb, nest);
 424
 425         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 426                 goto nla_put_failure;
 427
 428         return skb->len;
 429
 430 nla_put_failure:
 431         nla_nest_cancel(skb, nest);
 432         return -1;
 433 }
 434
 435 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
 436 {
 437         struct fw_filter *f = fh;
 438
 439         if (f && f->res.classid == classid)
 440                 f->res.class = cl;
 441 }
 442
 443 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 444         .kind           =       "fw",
 445         .classify       =       fw_classify,
 446         .init           =       fw_init,
 447         .destroy        =       fw_destroy,
 448         .get            =       fw_get,
 449         .change         =       fw_change,
 450         .delete         =       fw_delete,
 451         .walk           =       fw_walk,
 452         .dump           =       fw_dump,
 453         .bind_class     =       fw_bind_class,
 454         .owner          =       THIS_MODULE,
 455 };
 456
 457 static int __init init_fw(void)
 458 {
 459         return register_tcf_proto_ops(&cls_fw_ops);
 460 }
 461
 462 static void __exit exit_fw(void)
 463 {
 464         unregister_tcf_proto_ops(&cls_fw_ops);
 465 }
 466
 467 module_init(init_fw)
 468 module_exit(exit_fw)
 469 MODULE_LICENSE("GPL");