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