net/sched/cls_fw.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/cls_fw.c   Classifier mapping ipchains' fwmark to traffic class.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  *
   7  * Changes:
   8  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
   9  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
  10  * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/skbuff.h>
  20 #include <net/netlink.h>
  21 #include <net/act_api.h>
  22 #include <net/pkt_cls.h>
  23 #include <net/sch_generic.h>
  24
  25 #define HTSIZE 256
  26
  27 struct fw_head {
  28         u32                     mask;
  29         struct fw_filter __rcu  *ht[HTSIZE];
  30         struct rcu_head         rcu;
  31 };
  32
  33 struct fw_filter {
  34         struct fw_filter __rcu  *next;
  35         u32                     id;
  36         struct tcf_result       res;
  37         int                     ifindex;
  38         struct tcf_exts         exts;
  39         struct tcf_proto        *tp;
  40         struct rcu_work         rwork;
  41 };
  42
  43 static u32 fw_hash(u32 handle)
  44 {
  45         handle ^= (handle >> 16);
  46         handle ^= (handle >> 8);
  47         return handle % HTSIZE;
  48 }
  49
  50 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  51                        struct tcf_result *res)
  52 {
  53         struct fw_head *head = rcu_dereference_bh(tp->root);
  54         struct fw_filter *f;
  55         int r;
  56         u32 id = skb->mark;
  57
  58         if (head != NULL) {
  59                 id &= head->mask;
  60
  61                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  62                      f = rcu_dereference_bh(f->next)) {
  63                         if (f->id == id) {
  64                                 *res = f->res;
  65                                 if (!tcf_match_indev(skb, f->ifindex))
  66                                         continue;
  67                                 r = tcf_exts_exec(skb, &f->exts, res);
  68                                 if (r < 0)
  69                                         continue;
  70
  71                                 return r;
  72                         }
  73                 }
  74         } else {
  75                 struct Qdisc *q = tcf_block_q(tp->chain->block);
  76
  77                 /* Old method: classify the packet using its skb mark. */
  78                 if (id && (TC_H_MAJ(id) == 0 ||
  79                            !(TC_H_MAJ(id ^ q->handle)))) {
  80                         res->classid = id;
  81                         res->class = 0;
  82                         return 0;
  83                 }
  84         }
  85
  86         return -1;
  87 }
  88
  89 static void *fw_get(struct tcf_proto *tp, u32 handle)
  90 {
  91         struct fw_head *head = rtnl_dereference(tp->root);
  92         struct fw_filter *f;
  93
  94         if (head == NULL)
  95                 return NULL;
  96
  97         f = rtnl_dereference(head->ht[fw_hash(handle)]);
  98         for (; f; f = rtnl_dereference(f->next)) {
  99                 if (f->id == handle)
 100                         return f;
 101         }
 102         return NULL;
 103 }
 104
 105 static int fw_init(struct tcf_proto *tp)
 106 {
 107         /* We don't allocate fw_head here, because in the old method
 108          * we don't need it at all.
 109          */
 110         return 0;
 111 }
 112
 113 static void __fw_delete_filter(struct fw_filter *f)
 114 {
 115         tcf_exts_destroy(&f->exts);
 116         tcf_exts_put_net(&f->exts);
 117         kfree(f);
 118 }
 119
 120 static void fw_delete_filter_work(struct work_struct *work)
 121 {
 122         struct fw_filter *f = container_of(to_rcu_work(work),
 123                                            struct fw_filter,
 124                                            rwork);
 125         rtnl_lock();
 126         __fw_delete_filter(f);
 127         rtnl_unlock();
 128 }
 129
 130 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
 131                        struct netlink_ext_ack *extack)
 132 {
 133         struct fw_head *head = rtnl_dereference(tp->root);
 134         struct fw_filter *f;
 135         int h;
 136
 137         if (head == NULL)
 138                 return;
 139
 140         for (h = 0; h < HTSIZE; h++) {
 141                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 142                         RCU_INIT_POINTER(head->ht[h],
 143                                          rtnl_dereference(f->next));
 144                         tcf_unbind_filter(tp, &f->res);
 145                         if (tcf_exts_get_net(&f->exts))
 146                                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 147                         else
 148                                 __fw_delete_filter(f);
 149                 }
 150         }
 151         kfree_rcu(head, rcu);
 152 }
 153
 154 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
 155                      bool rtnl_held, struct netlink_ext_ack *extack)
 156 {
 157         struct fw_head *head = rtnl_dereference(tp->root);
 158         struct fw_filter *f = arg;
 159         struct fw_filter __rcu **fp;
 160         struct fw_filter *pfp;
 161         int ret = -EINVAL;
 162         int h;
 163
 164         if (head == NULL || f == NULL)
 165                 goto out;
 166
 167         fp = &head->ht[fw_hash(f->id)];
 168
 169         for (pfp = rtnl_dereference(*fp); pfp;
 170              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 171                 if (pfp == f) {
 172                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 173                         tcf_unbind_filter(tp, &f->res);
 174                         tcf_exts_get_net(&f->exts);
 175                         tcf_queue_work(&f->rwork, fw_delete_filter_work);
 176                         ret = 0;
 177                         break;
 178                 }
 179         }
 180
 181         *last = true;
 182         for (h = 0; h < HTSIZE; h++) {
 183                 if (rcu_access_pointer(head->ht[h])) {
 184                         *last = false;
 185                         break;
 186                 }
 187         }
 188
 189 out:
 190         return ret;
 191 }
 192
 193 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 194         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 195         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 196         [TCA_FW_MASK]           = { .type = NLA_U32 },
 197 };
 198
 199 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 200                         struct fw_filter *f, struct nlattr **tb,
 201                         struct nlattr **tca, unsigned long base, bool ovr,
 202                         struct netlink_ext_ack *extack)
 203 {
 204         struct fw_head *head = rtnl_dereference(tp->root);
 205         u32 mask;
 206         int err;
 207
 208         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
 209                                 true, extack);
 210         if (err < 0)
 211                 return err;
 212
 213         if (tb[TCA_FW_CLASSID]) {
 214                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 215                 tcf_bind_filter(tp, &f->res, base);
 216         }
 217
 218         if (tb[TCA_FW_INDEV]) {
 219                 int ret;
 220                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
 221                 if (ret < 0)
 222                         return ret;
 223                 f->ifindex = ret;
 224         }
 225
 226         err = -EINVAL;
 227         if (tb[TCA_FW_MASK]) {
 228                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 229                 if (mask != head->mask)
 230                         return err;
 231         } else if (head->mask != 0xFFFFFFFF)
 232                 return err;
 233
 234         return 0;
 235 }
 236
 237 static int fw_change(struct net *net, struct sk_buff *in_skb,
 238                      struct tcf_proto *tp, unsigned long base,
 239                      u32 handle, struct nlattr **tca, void **arg,
 240                      bool ovr, bool rtnl_held,
 241                      struct netlink_ext_ack *extack)
 242 {
 243         struct fw_head *head = rtnl_dereference(tp->root);
 244         struct fw_filter *f = *arg;
 245         struct nlattr *opt = tca[TCA_OPTIONS];
 246         struct nlattr *tb[TCA_FW_MAX + 1];
 247         int err;
 248
 249         if (!opt)
 250                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 251
 252         err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
 253                                           NULL);
 254         if (err < 0)
 255                 return err;
 256
 257         if (f) {
 258                 struct fw_filter *pfp, *fnew;
 259                 struct fw_filter __rcu **fp;
 260
 261                 if (f->id != handle && handle)
 262                         return -EINVAL;
 263
 264                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 265                 if (!fnew)
 266                         return -ENOBUFS;
 267
 268                 fnew->id = f->id;
 269                 fnew->res = f->res;
 270                 fnew->ifindex = f->ifindex;
 271                 fnew->tp = f->tp;
 272
 273                 err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
 274                                     TCA_FW_POLICE);
 275                 if (err < 0) {
 276                         kfree(fnew);
 277                         return err;
 278                 }
 279
 280                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
 281                 if (err < 0) {
 282                         tcf_exts_destroy(&fnew->exts);
 283                         kfree(fnew);
 284                         return err;
 285                 }
 286
 287                 fp = &head->ht[fw_hash(fnew->id)];
 288                 for (pfp = rtnl_dereference(*fp); pfp;
 289                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 290                         if (pfp == f)
 291                                 break;
 292
 293                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 294                 rcu_assign_pointer(*fp, fnew);
 295                 tcf_unbind_filter(tp, &f->res);
 296                 tcf_exts_get_net(&f->exts);
 297                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 298
 299                 *arg = fnew;
 300                 return err;
 301         }
 302
 303         if (!handle)
 304                 return -EINVAL;
 305
 306         if (!head) {
 307                 u32 mask = 0xFFFFFFFF;
 308                 if (tb[TCA_FW_MASK])
 309                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 310
 311                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 312                 if (!head)
 313                         return -ENOBUFS;
 314                 head->mask = mask;
 315
 316                 rcu_assign_pointer(tp->root, head);
 317         }
 318
 319         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 320         if (f == NULL)
 321                 return -ENOBUFS;
 322
 323         err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
 324         if (err < 0)
 325                 goto errout;
 326         f->id = handle;
 327         f->tp = tp;
 328
 329         err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
 330         if (err < 0)
 331                 goto errout;
 332
 333         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 334         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 335
 336         *arg = f;
 337         return 0;
 338
 339 errout:
 340         tcf_exts_destroy(&f->exts);
 341         kfree(f);
 342         return err;
 343 }
 344
 345 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 346                     bool rtnl_held)
 347 {
 348         struct fw_head *head = rtnl_dereference(tp->root);
 349         int h;
 350
 351         if (head == NULL)
 352                 arg->stop = 1;
 353
 354         if (arg->stop)
 355                 return;
 356
 357         for (h = 0; h < HTSIZE; h++) {
 358                 struct fw_filter *f;
 359
 360                 for (f = rtnl_dereference(head->ht[h]); f;
 361                      f = rtnl_dereference(f->next)) {
 362                         if (arg->count < arg->skip) {
 363                                 arg->count++;
 364                                 continue;
 365                         }
 366                         if (arg->fn(tp, f, arg) < 0) {
 367                                 arg->stop = 1;
 368                                 return;
 369                         }
 370                         arg->count++;
 371                 }
 372         }
 373 }
 374
 375 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 376                    struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 377 {
 378         struct fw_head *head = rtnl_dereference(tp->root);
 379         struct fw_filter *f = fh;
 380         struct nlattr *nest;
 381
 382         if (f == NULL)
 383                 return skb->len;
 384
 385         t->tcm_handle = f->id;
 386
 387         if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 388                 return skb->len;
 389
 390         nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
 391         if (nest == NULL)
 392                 goto nla_put_failure;
 393
 394         if (f->res.classid &&
 395             nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 396                 goto nla_put_failure;
 397         if (f->ifindex) {
 398                 struct net_device *dev;
 399                 dev = __dev_get_by_index(net, f->ifindex);
 400                 if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
 401                         goto nla_put_failure;
 402         }
 403         if (head->mask != 0xFFFFFFFF &&
 404             nla_put_u32(skb, TCA_FW_MASK, head->mask))
 405                 goto nla_put_failure;
 406
 407         if (tcf_exts_dump(skb, &f->exts) < 0)
 408                 goto nla_put_failure;
 409
 410         nla_nest_end(skb, nest);
 411
 412         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 413                 goto nla_put_failure;
 414
 415         return skb->len;
 416
 417 nla_put_failure:
 418         nla_nest_cancel(skb, nest);
 419         return -1;
 420 }
 421
 422 static void fw_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
 423                           unsigned long base)
 424 {
 425         struct fw_filter *f = fh;
 426
 427         if (f && f->res.classid == classid) {
 428                 if (cl)
 429                         __tcf_bind_filter(q, &f->res, base);
 430                 else
 431                         __tcf_unbind_filter(q, &f->res);
 432         }
 433 }
 434
 435 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
 436         .kind           =       "fw",
 437         .classify       =       fw_classify,
 438         .init           =       fw_init,
 439         .destroy        =       fw_destroy,
 440         .get            =       fw_get,
 441         .change         =       fw_change,
 442         .delete         =       fw_delete,
 443         .walk           =       fw_walk,
 444         .dump           =       fw_dump,
 445         .bind_class     =       fw_bind_class,
 446         .owner          =       THIS_MODULE,
 447 };
 448
 449 static int __init init_fw(void)
 450 {
 451         return register_tcf_proto_ops(&cls_fw_ops);
 452 }
 453
 454 static void __exit exit_fw(void)
 455 {
 456         unregister_tcf_proto_ops(&cls_fw_ops);
 457 }
 458
 459 module_init(init_fw)
 460 module_exit(exit_fw)
 461 MODULE_LICENSE("GPL");