net/sched/act_pedit.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/act_pedit.c        Generic packet editor
   4  *
   5  * Authors:     Jamal Hadi Salim (2002-4)
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/errno.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <net/netlink.h>
  18 #include <net/pkt_sched.h>
  19 #include <linux/tc_act/tc_pedit.h>
  20 #include <net/tc_act/tc_pedit.h>
  21 #include <uapi/linux/tc_act/tc_pedit.h>
  22 #include <net/pkt_cls.h>
  23 #include <net/tc_wrapper.h>
  24
  25 static struct tc_action_ops act_pedit_ops;
  26
  27 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  28         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  29         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  30 };
  31
  32 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  33         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  34         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  35 };
  36
  37 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  38                                                         u8 n)
  39 {
  40         struct tcf_pedit_key_ex *keys_ex;
  41         struct tcf_pedit_key_ex *k;
  42         const struct nlattr *ka;
  43         int err = -EINVAL;
  44         int rem;
  45
  46         if (!nla)
  47                 return NULL;
  48
  49         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  50         if (!keys_ex)
  51                 return ERR_PTR(-ENOMEM);
  52
  53         k = keys_ex;
  54
  55         nla_for_each_nested(ka, nla, rem) {
  56                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  57
  58                 if (!n) {
  59                         err = -EINVAL;
  60                         goto err_out;
  61                 }
  62                 n--;
  63
  64                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  65                         err = -EINVAL;
  66                         goto err_out;
  67                 }
  68
  69                 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
  70                                                   ka, pedit_key_ex_policy,
  71                                                   NULL);
  72                 if (err)
  73                         goto err_out;
  74
  75                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  76                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  77                         err = -EINVAL;
  78                         goto err_out;
  79                 }
  80
  81                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  82                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  83
  84                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  85                     k->cmd > TCA_PEDIT_CMD_MAX) {
  86                         err = -EINVAL;
  87                         goto err_out;
  88                 }
  89
  90                 k++;
  91         }
  92
  93         if (n) {
  94                 err = -EINVAL;
  95                 goto err_out;
  96         }
  97
  98         return keys_ex;
  99
 100 err_out:
 101         kfree(keys_ex);
 102         return ERR_PTR(err);
 103 }
 104
 105 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 106                                  struct tcf_pedit_key_ex *keys_ex, int n)
 107 {
 108         struct nlattr *keys_start = nla_nest_start_noflag(skb,
 109                                                           TCA_PEDIT_KEYS_EX);
 110
 111         if (!keys_start)
 112                 goto nla_failure;
 113         for (; n > 0; n--) {
 114                 struct nlattr *key_start;
 115
 116                 key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
 117                 if (!key_start)
 118                         goto nla_failure;
 119
 120                 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 121                     nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
 122                         goto nla_failure;
 123
 124                 nla_nest_end(skb, key_start);
 125
 126                 keys_ex++;
 127         }
 128
 129         nla_nest_end(skb, keys_start);
 130
 131         return 0;
 132 nla_failure:
 133         nla_nest_cancel(skb, keys_start);
 134         return -EINVAL;
 135 }
 136
 137 static void tcf_pedit_cleanup_rcu(struct rcu_head *head)
 138 {
 139         struct tcf_pedit_parms *parms =
 140                 container_of(head, struct tcf_pedit_parms, rcu);
 141
 142         kfree(parms->tcfp_keys_ex);
 143         kfree(parms->tcfp_keys);
 144
 145         kfree(parms);
 146 }
 147
 148 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 149                           struct nlattr *est, struct tc_action **a,
 150                           struct tcf_proto *tp, u32 flags,
 151                           struct netlink_ext_ack *extack)
 152 {
 153         struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
 154         bool bind = flags & TCA_ACT_FLAGS_BIND;
 155         struct tcf_chain *goto_ch = NULL;
 156         struct tcf_pedit_parms *oparms, *nparms;
 157         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 158         struct tc_pedit *parm;
 159         struct nlattr *pattr;
 160         struct tcf_pedit *p;
 161         int ret = 0, err;
 162         int i, ksize;
 163         u32 index;
 164
 165         if (!nla) {
 166                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 167                 return -EINVAL;
 168         }
 169
 170         err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 171                                           pedit_policy, NULL);
 172         if (err < 0)
 173                 return err;
 174
 175         pattr = tb[TCA_PEDIT_PARMS];
 176         if (!pattr)
 177                 pattr = tb[TCA_PEDIT_PARMS_EX];
 178         if (!pattr) {
 179                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 180                 return -EINVAL;
 181         }
 182
 183         parm = nla_data(pattr);
 184         if (!parm->nkeys) {
 185                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 186                 return -EINVAL;
 187         }
 188         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 189         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 190                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 191                 return -EINVAL;
 192         }
 193
 194         nparms = kzalloc(sizeof(*nparms), GFP_KERNEL);
 195         if (!nparms)
 196                 return -ENOMEM;
 197
 198         nparms->tcfp_keys_ex =
 199                 tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 200         if (IS_ERR(nparms->tcfp_keys_ex)) {
 201                 ret = PTR_ERR(nparms->tcfp_keys_ex);
 202                 goto out_free;
 203         }
 204
 205         index = parm->index;
 206         err = tcf_idr_check_alloc(tn, &index, a, bind);
 207         if (!err) {
 208                 ret = tcf_idr_create_from_flags(tn, index, est, a,
 209                                                 &act_pedit_ops, bind, flags);
 210                 if (ret) {
 211                         tcf_idr_cleanup(tn, index);
 212                         goto out_free_ex;
 213                 }
 214                 ret = ACT_P_CREATED;
 215         } else if (err > 0) {
 216                 if (bind)
 217                         goto out_free;
 218                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 219                         ret = -EEXIST;
 220                         goto out_release;
 221                 }
 222         } else {
 223                 ret = err;
 224                 goto out_free_ex;
 225         }
 226
 227         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 228         if (err < 0) {
 229                 ret = err;
 230                 goto out_release;
 231         }
 232
 233         nparms->tcfp_off_max_hint = 0;
 234         nparms->tcfp_flags = parm->flags;
 235         nparms->tcfp_nkeys = parm->nkeys;
 236
 237         nparms->tcfp_keys = kmalloc(ksize, GFP_KERNEL);
 238         if (!nparms->tcfp_keys) {
 239                 ret = -ENOMEM;
 240                 goto put_chain;
 241         }
 242
 243         memcpy(nparms->tcfp_keys, parm->keys, ksize);
 244
 245         for (i = 0; i < nparms->tcfp_nkeys; ++i) {
 246                 u32 cur = nparms->tcfp_keys[i].off;
 247
 248                 /* sanitize the shift value for any later use */
 249                 nparms->tcfp_keys[i].shift = min_t(size_t,
 250                                                    BITS_PER_TYPE(int) - 1,
 251                                                    nparms->tcfp_keys[i].shift);
 252
 253                 /* The AT option can read a single byte, we can bound the actual
 254                  * value with uchar max.
 255                  */
 256                 cur += (0xff & nparms->tcfp_keys[i].offmask) >> nparms->tcfp_keys[i].shift;
 257
 258                 /* Each key touches 4 bytes starting from the computed offset */
 259                 nparms->tcfp_off_max_hint =
 260                         max(nparms->tcfp_off_max_hint, cur + 4);
 261         }
 262
 263         p = to_pedit(*a);
 264
 265         spin_lock_bh(&p->tcf_lock);
 266         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 267         oparms = rcu_replace_pointer(p->parms, nparms, 1);
 268         spin_unlock_bh(&p->tcf_lock);
 269
 270         if (oparms)
 271                 call_rcu(&oparms->rcu, tcf_pedit_cleanup_rcu);
 272
 273         if (goto_ch)
 274                 tcf_chain_put_by_act(goto_ch);
 275
 276         return ret;
 277
 278 put_chain:
 279         if (goto_ch)
 280                 tcf_chain_put_by_act(goto_ch);
 281 out_release:
 282         tcf_idr_release(*a, bind);
 283 out_free_ex:
 284         kfree(nparms->tcfp_keys_ex);
 285 out_free:
 286         kfree(nparms);
 287         return ret;
 288 }
 289
 290 static void tcf_pedit_cleanup(struct tc_action *a)
 291 {
 292         struct tcf_pedit *p = to_pedit(a);
 293         struct tcf_pedit_parms *parms;
 294
 295         parms = rcu_dereference_protected(p->parms, 1);
 296
 297         if (parms)
 298                 call_rcu(&parms->rcu, tcf_pedit_cleanup_rcu);
 299 }
 300
 301 static bool offset_valid(struct sk_buff *skb, int offset)
 302 {
 303         if (offset > 0 && offset > skb->len)
 304                 return false;
 305
 306         if  (offset < 0 && -offset > skb_headroom(skb))
 307                 return false;
 308
 309         return true;
 310 }
 311
 312 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 313                                 enum pedit_header_type htype, int *hoffset)
 314 {
 315         int ret = -EINVAL;
 316
 317         switch (htype) {
 318         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 319                 if (skb_mac_header_was_set(skb)) {
 320                         *hoffset = skb_mac_offset(skb);
 321                         ret = 0;
 322                 }
 323                 break;
 324         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 325         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 326         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 327                 *hoffset = skb_network_offset(skb);
 328                 ret = 0;
 329                 break;
 330         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 331         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 332                 if (skb_transport_header_was_set(skb)) {
 333                         *hoffset = skb_transport_offset(skb);
 334                         ret = 0;
 335                 }
 336                 break;
 337         default:
 338                 ret = -EINVAL;
 339                 break;
 340         }
 341
 342         return ret;
 343 }
 344
 345 TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 346                                     const struct tc_action *a,
 347                                     struct tcf_result *res)
 348 {
 349         enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 350         enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 351         struct tcf_pedit *p = to_pedit(a);
 352         struct tcf_pedit_key_ex *tkey_ex;
 353         struct tcf_pedit_parms *parms;
 354         struct tc_pedit_key *tkey;
 355         u32 max_offset;
 356         int i;
 357
 358         parms = rcu_dereference_bh(p->parms);
 359
 360         max_offset = (skb_transport_header_was_set(skb) ?
 361                       skb_transport_offset(skb) :
 362                       skb_network_offset(skb)) +
 363                      parms->tcfp_off_max_hint;
 364         if (skb_ensure_writable(skb, min(skb->len, max_offset)))
 365                 goto done;
 366
 367         tcf_lastuse_update(&p->tcf_tm);
 368         tcf_action_update_bstats(&p->common, skb);
 369
 370         tkey = parms->tcfp_keys;
 371         tkey_ex = parms->tcfp_keys_ex;
 372
 373         for (i = parms->tcfp_nkeys; i > 0; i--, tkey++) {
 374                 int offset = tkey->off;
 375                 u32 *ptr, hdata;
 376                 int hoffset;
 377                 u32 val;
 378                 int rc;
 379
 380                 if (tkey_ex) {
 381                         htype = tkey_ex->htype;
 382                         cmd = tkey_ex->cmd;
 383
 384                         tkey_ex++;
 385                 }
 386
 387                 rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 388                 if (rc) {
 389                         pr_info("tc action pedit bad header type specified (0x%x)\n",
 390                                 htype);
 391                         goto bad;
 392                 }
 393
 394                 if (tkey->offmask) {
 395                         u8 *d, _d;
 396
 397                         if (!offset_valid(skb, hoffset + tkey->at)) {
 398                                 pr_info("tc action pedit 'at' offset %d out of bounds\n",
 399                                         hoffset + tkey->at);
 400                                 goto bad;
 401                         }
 402                         d = skb_header_pointer(skb, hoffset + tkey->at,
 403                                                sizeof(_d), &_d);
 404                         if (!d)
 405                                 goto bad;
 406                         offset += (*d & tkey->offmask) >> tkey->shift;
 407                 }
 408
 409                 if (offset % 4) {
 410                         pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 411                         goto bad;
 412                 }
 413
 414                 if (!offset_valid(skb, hoffset + offset)) {
 415                         pr_info("tc action pedit offset %d out of bounds\n",
 416                                 hoffset + offset);
 417                         goto bad;
 418                 }
 419
 420                 ptr = skb_header_pointer(skb, hoffset + offset,
 421                                          sizeof(hdata), &hdata);
 422                 if (!ptr)
 423                         goto bad;
 424                 /* just do it, baby */
 425                 switch (cmd) {
 426                 case TCA_PEDIT_KEY_EX_CMD_SET:
 427                         val = tkey->val;
 428                         break;
 429                 case TCA_PEDIT_KEY_EX_CMD_ADD:
 430                         val = (*ptr + tkey->val) & ~tkey->mask;
 431                         break;
 432                 default:
 433                         pr_info("tc action pedit bad command (%d)\n",
 434                                 cmd);
 435                         goto bad;
 436                 }
 437
 438                 *ptr = ((*ptr & tkey->mask) ^ val);
 439                 if (ptr == &hdata)
 440                         skb_store_bits(skb, hoffset + offset, ptr, 4);
 441         }
 442
 443         goto done;
 444
 445 bad:
 446         spin_lock(&p->tcf_lock);
 447         p->tcf_qstats.overlimits++;
 448         spin_unlock(&p->tcf_lock);
 449 done:
 450         return p->tcf_action;
 451 }
 452
 453 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
 454                                    u64 drops, u64 lastuse, bool hw)
 455 {
 456         struct tcf_pedit *d = to_pedit(a);
 457         struct tcf_t *tm = &d->tcf_tm;
 458
 459         tcf_action_update_stats(a, bytes, packets, drops, hw);
 460         tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 461 }
 462
 463 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 464                           int bind, int ref)
 465 {
 466         unsigned char *b = skb_tail_pointer(skb);
 467         struct tcf_pedit *p = to_pedit(a);
 468         struct tcf_pedit_parms *parms;
 469         struct tc_pedit *opt;
 470         struct tcf_t t;
 471         int s;
 472
 473         spin_lock_bh(&p->tcf_lock);
 474         parms = rcu_dereference_protected(p->parms, 1);
 475         s = struct_size(opt, keys, parms->tcfp_nkeys);
 476
 477         opt = kzalloc(s, GFP_ATOMIC);
 478         if (unlikely(!opt)) {
 479                 spin_unlock_bh(&p->tcf_lock);
 480                 return -ENOBUFS;
 481         }
 482
 483         memcpy(opt->keys, parms->tcfp_keys,
 484                flex_array_size(opt, keys, parms->tcfp_nkeys));
 485         opt->index = p->tcf_index;
 486         opt->nkeys = parms->tcfp_nkeys;
 487         opt->flags = parms->tcfp_flags;
 488         opt->action = p->tcf_action;
 489         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 490         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 491
 492         if (parms->tcfp_keys_ex) {
 493                 if (tcf_pedit_key_ex_dump(skb, parms->tcfp_keys_ex,
 494                                           parms->tcfp_nkeys))
 495                         goto nla_put_failure;
 496
 497                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 498                         goto nla_put_failure;
 499         } else {
 500                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 501                         goto nla_put_failure;
 502         }
 503
 504         tcf_tm_dump(&t, &p->tcf_tm);
 505         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 506                 goto nla_put_failure;
 507         spin_unlock_bh(&p->tcf_lock);
 508
 509         kfree(opt);
 510         return skb->len;
 511
 512 nla_put_failure:
 513         spin_unlock_bh(&p->tcf_lock);
 514         nlmsg_trim(skb, b);
 515         kfree(opt);
 516         return -1;
 517 }
 518
 519 static int tcf_pedit_offload_act_setup(struct tc_action *act, void *entry_data,
 520                                        u32 *index_inc, bool bind,
 521                                        struct netlink_ext_ack *extack)
 522 {
 523         if (bind) {
 524                 struct flow_action_entry *entry = entry_data;
 525                 int k;
 526
 527                 for (k = 0; k < tcf_pedit_nkeys(act); k++) {
 528                         switch (tcf_pedit_cmd(act, k)) {
 529                         case TCA_PEDIT_KEY_EX_CMD_SET:
 530                                 entry->id = FLOW_ACTION_MANGLE;
 531                                 break;
 532                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 533                                 entry->id = FLOW_ACTION_ADD;
 534                                 break;
 535                         default:
 536                                 NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 537                                 return -EOPNOTSUPP;
 538                         }
 539                         entry->mangle.htype = tcf_pedit_htype(act, k);
 540                         entry->mangle.mask = tcf_pedit_mask(act, k);
 541                         entry->mangle.val = tcf_pedit_val(act, k);
 542                         entry->mangle.offset = tcf_pedit_offset(act, k);
 543                         entry->hw_stats = tc_act_hw_stats(act->hw_stats);
 544                         entry++;
 545                 }
 546                 *index_inc = k;
 547         } else {
 548                 struct flow_offload_action *fl_action = entry_data;
 549                 u32 cmd = tcf_pedit_cmd(act, 0);
 550                 int k;
 551
 552                 switch (cmd) {
 553                 case TCA_PEDIT_KEY_EX_CMD_SET:
 554                         fl_action->id = FLOW_ACTION_MANGLE;
 555                         break;
 556                 case TCA_PEDIT_KEY_EX_CMD_ADD:
 557                         fl_action->id = FLOW_ACTION_ADD;
 558                         break;
 559                 default:
 560                         NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 561                         return -EOPNOTSUPP;
 562                 }
 563
 564                 for (k = 1; k < tcf_pedit_nkeys(act); k++) {
 565                         if (cmd != tcf_pedit_cmd(act, k)) {
 566                                 NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 567                                 return -EOPNOTSUPP;
 568                         }
 569                 }
 570         }
 571
 572         return 0;
 573 }
 574
 575 static struct tc_action_ops act_pedit_ops = {
 576         .kind           =       "pedit",
 577         .id             =       TCA_ID_PEDIT,
 578         .owner          =       THIS_MODULE,
 579         .act            =       tcf_pedit_act,
 580         .stats_update   =       tcf_pedit_stats_update,
 581         .dump           =       tcf_pedit_dump,
 582         .cleanup        =       tcf_pedit_cleanup,
 583         .init           =       tcf_pedit_init,
 584         .offload_act_setup =    tcf_pedit_offload_act_setup,
 585         .size           =       sizeof(struct tcf_pedit),
 586 };
 587
 588 static __net_init int pedit_init_net(struct net *net)
 589 {
 590         struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
 591
 592         return tc_action_net_init(net, tn, &act_pedit_ops);
 593 }
 594
 595 static void __net_exit pedit_exit_net(struct list_head *net_list)
 596 {
 597         tc_action_net_exit(net_list, act_pedit_ops.net_id);
 598 }
 599
 600 static struct pernet_operations pedit_net_ops = {
 601         .init = pedit_init_net,
 602         .exit_batch = pedit_exit_net,
 603         .id   = &act_pedit_ops.net_id,
 604         .size = sizeof(struct tc_action_net),
 605 };
 606
 607 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 608 MODULE_DESCRIPTION("Generic Packet Editor actions");
 609 MODULE_LICENSE("GPL");
 610
 611 static int __init pedit_init_module(void)
 612 {
 613         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 614 }
 615
 616 static void __exit pedit_cleanup_module(void)
 617 {
 618         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 619 }
 620
 621 module_init(pedit_init_module);
 622 module_exit(pedit_cleanup_module);