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  * JHS: We should remove the CONFIG_NET_CLS_IND from here
  13  * eventually when the meta match extension is made available
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/skbuff.h>
  23 #include <net/netlink.h>
  24 #include <net/act_api.h>
  25 #include <net/pkt_cls.h>
  26 #include <net/sch_generic.h>
  27
  28 #define HTSIZE 256
  29
  30 struct fw_head {
  31         u32                     mask;
  32         struct fw_filter __rcu  *ht[HTSIZE];
  33         struct rcu_head         rcu;
  34 };
  35
  36 struct fw_filter {
  37         struct fw_filter __rcu  *next;
  38         u32                     id;
  39         struct tcf_result       res;
  40 #ifdef CONFIG_NET_CLS_IND
  41         int                     ifindex;
  42 #endif /* CONFIG_NET_CLS_IND */
  43         struct tcf_exts         exts;
  44         struct tcf_proto        *tp;
  45         struct rcu_work         rwork;
  46 };
  47
  48 static u32 fw_hash(u32 handle)
  49 {
  50         handle ^= (handle >> 16);
  51         handle ^= (handle >> 8);
  52         return handle % HTSIZE;
  53 }
  54
  55 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  56                        struct tcf_result *res)
  57 {
  58         struct fw_head *head = rcu_dereference_bh(tp->root);
  59         struct fw_filter *f;
  60         int r;
  61         u32 id = skb->mark;
  62
  63         if (head != NULL) {
  64                 id &= head->mask;
  65
  66                 for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  67                      f = rcu_dereference_bh(f->next)) {
  68                         if (f->id == id) {
  69                                 *res = f->res;
  70 #ifdef CONFIG_NET_CLS_IND
  71                                 if (!tcf_match_indev(skb, f->ifindex))
  72                                         continue;
  73 #endif /* CONFIG_NET_CLS_IND */
  74                                 r = tcf_exts_exec(skb, &f->exts, res);
  75                                 if (r < 0)
  76                                         continue;
  77
  78                                 return r;
  79                         }
  80                 }
  81         } else {
  82                 struct Qdisc *q = tcf_block_q(tp->chain->block);
  83
  84                 /* Old method: classify the packet using its skb mark. */
  85                 if (id && (TC_H_MAJ(id) == 0 ||
  86                            !(TC_H_MAJ(id ^ q->handle)))) {
  87                         res->classid = id;
  88                         res->class = 0;
  89                         return 0;
  90                 }
  91         }
  92
  93         return -1;
  94 }
  95
  96 static void *fw_get(struct tcf_proto *tp, u32 handle)
  97 {
  98         struct fw_head *head = rtnl_dereference(tp->root);
  99         struct fw_filter *f;
 100
 101         if (head == NULL)
 102                 return NULL;
 103
 104         f = rtnl_dereference(head->ht[fw_hash(handle)]);
 105         for (; f; f = rtnl_dereference(f->next)) {
 106                 if (f->id == handle)
 107                         return f;
 108         }
 109         return NULL;
 110 }
 111
 112 static int fw_init(struct tcf_proto *tp)
 113 {
 114         /* We don't allocate fw_head here, because in the old method
 115          * we don't need it at all.
 116          */
 117         return 0;
 118 }
 119
 120 static void __fw_delete_filter(struct fw_filter *f)
 121 {
 122         tcf_exts_destroy(&f->exts);
 123         tcf_exts_put_net(&f->exts);
 124         kfree(f);
 125 }
 126
 127 static void fw_delete_filter_work(struct work_struct *work)
 128 {
 129         struct fw_filter *f = container_of(to_rcu_work(work),
 130                                            struct fw_filter,
 131                                            rwork);
 132         rtnl_lock();
 133         __fw_delete_filter(f);
 134         rtnl_unlock();
 135 }
 136
 137 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
 138                        struct netlink_ext_ack *extack)
 139 {
 140         struct fw_head *head = rtnl_dereference(tp->root);
 141         struct fw_filter *f;
 142         int h;
 143
 144         if (head == NULL)
 145                 return;
 146
 147         for (h = 0; h < HTSIZE; h++) {
 148                 while ((f = rtnl_dereference(head->ht[h])) != NULL) {
 149                         RCU_INIT_POINTER(head->ht[h],
 150                                          rtnl_dereference(f->next));
 151                         tcf_unbind_filter(tp, &f->res);
 152                         if (tcf_exts_get_net(&f->exts))
 153                                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 154                         else
 155                                 __fw_delete_filter(f);
 156                 }
 157         }
 158         kfree_rcu(head, rcu);
 159 }
 160
 161 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
 162                      bool rtnl_held, struct netlink_ext_ack *extack)
 163 {
 164         struct fw_head *head = rtnl_dereference(tp->root);
 165         struct fw_filter *f = arg;
 166         struct fw_filter __rcu **fp;
 167         struct fw_filter *pfp;
 168         int ret = -EINVAL;
 169         int h;
 170
 171         if (head == NULL || f == NULL)
 172                 goto out;
 173
 174         fp = &head->ht[fw_hash(f->id)];
 175
 176         for (pfp = rtnl_dereference(*fp); pfp;
 177              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 178                 if (pfp == f) {
 179                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 180                         tcf_unbind_filter(tp, &f->res);
 181                         tcf_exts_get_net(&f->exts);
 182                         tcf_queue_work(&f->rwork, fw_delete_filter_work);
 183                         ret = 0;
 184                         break;
 185                 }
 186         }
 187
 188         *last = true;
 189         for (h = 0; h < HTSIZE; h++) {
 190                 if (rcu_access_pointer(head->ht[h])) {
 191                         *last = false;
 192                         break;
 193                 }
 194         }
 195
 196 out:
 197         return ret;
 198 }
 199
 200 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
 201         [TCA_FW_CLASSID]        = { .type = NLA_U32 },
 202         [TCA_FW_INDEV]          = { .type = NLA_STRING, .len = IFNAMSIZ },
 203         [TCA_FW_MASK]           = { .type = NLA_U32 },
 204 };
 205
 206 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 207                         struct fw_filter *f, struct nlattr **tb,
 208                         struct nlattr **tca, unsigned long base, bool ovr,
 209                         struct netlink_ext_ack *extack)
 210 {
 211         struct fw_head *head = rtnl_dereference(tp->root);
 212         u32 mask;
 213         int err;
 214
 215         err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
 216                                 true, extack);
 217         if (err < 0)
 218                 return err;
 219
 220         if (tb[TCA_FW_CLASSID]) {
 221                 f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
 222                 tcf_bind_filter(tp, &f->res, base);
 223         }
 224
 225 #ifdef CONFIG_NET_CLS_IND
 226         if (tb[TCA_FW_INDEV]) {
 227                 int ret;
 228                 ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
 229                 if (ret < 0)
 230                         return ret;
 231                 f->ifindex = ret;
 232         }
 233 #endif /* CONFIG_NET_CLS_IND */
 234
 235         err = -EINVAL;
 236         if (tb[TCA_FW_MASK]) {
 237                 mask = nla_get_u32(tb[TCA_FW_MASK]);
 238                 if (mask != head->mask)
 239                         return err;
 240         } else if (head->mask != 0xFFFFFFFF)
 241                 return err;
 242
 243         return 0;
 244 }
 245
 246 static int fw_change(struct net *net, struct sk_buff *in_skb,
 247                      struct tcf_proto *tp, unsigned long base,
 248                      u32 handle, struct nlattr **tca, void **arg,
 249                      bool ovr, bool rtnl_held,
 250                      struct netlink_ext_ack *extack)
 251 {
 252         struct fw_head *head = rtnl_dereference(tp->root);
 253         struct fw_filter *f = *arg;
 254         struct nlattr *opt = tca[TCA_OPTIONS];
 255         struct nlattr *tb[TCA_FW_MAX + 1];
 256         int err;
 257
 258         if (!opt)
 259                 return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 260
 261         err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
 262                                           NULL);
 263         if (err < 0)
 264                 return err;
 265
 266         if (f) {
 267                 struct fw_filter *pfp, *fnew;
 268                 struct fw_filter __rcu **fp;
 269
 270                 if (f->id != handle && handle)
 271                         return -EINVAL;
 272
 273                 fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 274                 if (!fnew)
 275                         return -ENOBUFS;
 276
 277                 fnew->id = f->id;
 278                 fnew->res = f->res;
 279 #ifdef CONFIG_NET_CLS_IND
 280                 fnew->ifindex = f->ifindex;
 281 #endif /* CONFIG_NET_CLS_IND */
 282                 fnew->tp = f->tp;
 283
 284                 err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
 285                                     TCA_FW_POLICE);
 286                 if (err < 0) {
 287                         kfree(fnew);
 288                         return err;
 289                 }
 290
 291                 err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
 292                 if (err < 0) {
 293                         tcf_exts_destroy(&fnew->exts);
 294                         kfree(fnew);
 295                         return err;
 296                 }
 297
 298                 fp = &head->ht[fw_hash(fnew->id)];
 299                 for (pfp = rtnl_dereference(*fp); pfp;
 300                      fp = &pfp->next, pfp = rtnl_dereference(*fp))
 301                         if (pfp == f)
 302                                 break;
 303
 304                 RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
 305                 rcu_assign_pointer(*fp, fnew);
 306                 tcf_unbind_filter(tp, &f->res);
 307                 tcf_exts_get_net(&f->exts);
 308                 tcf_queue_work(&f->rwork, fw_delete_filter_work);
 309
 310                 *arg = fnew;
 311                 return err;
 312         }
 313
 314         if (!handle)
 315                 return -EINVAL;
 316
 317         if (!head) {
 318                 u32 mask = 0xFFFFFFFF;
 319                 if (tb[TCA_FW_MASK])
 320                         mask = nla_get_u32(tb[TCA_FW_MASK]);
 321
 322                 head = kzalloc(sizeof(*head), GFP_KERNEL);
 323                 if (!head)
 324                         return -ENOBUFS;
 325                 head->mask = mask;
 326
 327                 rcu_assign_pointer(tp->root, head);
 328         }
 329
 330         f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 331         if (f == NULL)
 332                 return -ENOBUFS;
 333
 334         err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
 335         if (err < 0)
 336                 goto errout;
 337         f->id = handle;
 338         f->tp = tp;
 339
 340         err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
 341         if (err < 0)
 342                 goto errout;
 343
 344         RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
 345         rcu_assign_pointer(head->ht[fw_hash(handle)], f);
 346
 347         *arg = f;
 348         return 0;
 349
 350 errout:
 351         tcf_exts_destroy(&f->exts);
 352         kfree(f);
 353         return err;
 354 }
 355
 356 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 357                     bool rtnl_held)
 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, bool rtnl_held)
 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_noflag(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");