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
 185         index = parm->index;
 186         err = tcf_idr_check_alloc(tn, &index, a, bind);
 187         if (!err) {
 188                 ret = tcf_idr_create_from_flags(tn, index, est, a,
 189                                                 &act_pedit_ops, bind, flags);
 190                 if (ret) {
 191                         tcf_idr_cleanup(tn, index);
 192                         return ret;
 193                 }
 194                 ret = ACT_P_CREATED;
 195         } else if (err > 0) {
 196                 if (bind)
 197                         return 0;
 198                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 199                         ret = -EEXIST;
 200                         goto out_release;
 201                 }
 202         } else {
 203                 return err;
 204         }
 205
 206         if (!parm->nkeys) {
 207                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 208                 ret = -EINVAL;
 209                 goto out_release;
 210         }
 211         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 212         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 213                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 214                 ret = -EINVAL;
 215                 goto out_release;
 216         }
 217
 218         nparms = kzalloc(sizeof(*nparms), GFP_KERNEL);
 219         if (!nparms) {
 220                 ret = -ENOMEM;
 221                 goto out_release;
 222         }
 223
 224         nparms->tcfp_keys_ex =
 225                 tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 226         if (IS_ERR(nparms->tcfp_keys_ex)) {
 227                 ret = PTR_ERR(nparms->tcfp_keys_ex);
 228                 goto out_free;
 229         }
 230
 231         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 232         if (err < 0) {
 233                 ret = err;
 234                 goto out_free_ex;
 235         }
 236
 237         nparms->tcfp_off_max_hint = 0;
 238         nparms->tcfp_flags = parm->flags;
 239         nparms->tcfp_nkeys = parm->nkeys;
 240
 241         nparms->tcfp_keys = kmalloc(ksize, GFP_KERNEL);
 242         if (!nparms->tcfp_keys) {
 243                 ret = -ENOMEM;
 244                 goto put_chain;
 245         }
 246
 247         memcpy(nparms->tcfp_keys, parm->keys, ksize);
 248
 249         for (i = 0; i < nparms->tcfp_nkeys; ++i) {
 250                 u32 cur = nparms->tcfp_keys[i].off;
 251
 252                 /* sanitize the shift value for any later use */
 253                 nparms->tcfp_keys[i].shift = min_t(size_t,
 254                                                    BITS_PER_TYPE(int) - 1,
 255                                                    nparms->tcfp_keys[i].shift);
 256
 257                 /* The AT option can read a single byte, we can bound the actual
 258                  * value with uchar max.
 259                  */
 260                 cur += (0xff & nparms->tcfp_keys[i].offmask) >> nparms->tcfp_keys[i].shift;
 261
 262                 /* Each key touches 4 bytes starting from the computed offset */
 263                 nparms->tcfp_off_max_hint =
 264                         max(nparms->tcfp_off_max_hint, cur + 4);
 265         }
 266
 267         p = to_pedit(*a);
 268
 269         spin_lock_bh(&p->tcf_lock);
 270         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 271         oparms = rcu_replace_pointer(p->parms, nparms, 1);
 272         spin_unlock_bh(&p->tcf_lock);
 273
 274         if (oparms)
 275                 call_rcu(&oparms->rcu, tcf_pedit_cleanup_rcu);
 276
 277         if (goto_ch)
 278                 tcf_chain_put_by_act(goto_ch);
 279
 280         return ret;
 281
 282 put_chain:
 283         if (goto_ch)
 284                 tcf_chain_put_by_act(goto_ch);
 285 out_free_ex:
 286         kfree(nparms->tcfp_keys_ex);
 287 out_free:
 288         kfree(nparms);
 289 out_release:
 290         tcf_idr_release(*a, bind);
 291         return ret;
 292 }
 293
 294 static void tcf_pedit_cleanup(struct tc_action *a)
 295 {
 296         struct tcf_pedit *p = to_pedit(a);
 297         struct tcf_pedit_parms *parms;
 298
 299         parms = rcu_dereference_protected(p->parms, 1);
 300
 301         if (parms)
 302                 call_rcu(&parms->rcu, tcf_pedit_cleanup_rcu);
 303 }
 304
 305 static bool offset_valid(struct sk_buff *skb, int offset)
 306 {
 307         if (offset > 0 && offset > skb->len)
 308                 return false;
 309
 310         if  (offset < 0 && -offset > skb_headroom(skb))
 311                 return false;
 312
 313         return true;
 314 }
 315
 316 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 317                                 enum pedit_header_type htype, int *hoffset)
 318 {
 319         int ret = -EINVAL;
 320
 321         switch (htype) {
 322         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 323                 if (skb_mac_header_was_set(skb)) {
 324                         *hoffset = skb_mac_offset(skb);
 325                         ret = 0;
 326                 }
 327                 break;
 328         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 329         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 330         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 331                 *hoffset = skb_network_offset(skb);
 332                 ret = 0;
 333                 break;
 334         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 335         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 336                 if (skb_transport_header_was_set(skb)) {
 337                         *hoffset = skb_transport_offset(skb);
 338                         ret = 0;
 339                 }
 340                 break;
 341         default:
 342                 ret = -EINVAL;
 343                 break;
 344         }
 345
 346         return ret;
 347 }
 348
 349 TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 350                                     const struct tc_action *a,
 351                                     struct tcf_result *res)
 352 {
 353         enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 354         enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 355         struct tcf_pedit *p = to_pedit(a);
 356         struct tcf_pedit_key_ex *tkey_ex;
 357         struct tcf_pedit_parms *parms;
 358         struct tc_pedit_key *tkey;
 359         u32 max_offset;
 360         int i;
 361
 362         parms = rcu_dereference_bh(p->parms);
 363
 364         max_offset = (skb_transport_header_was_set(skb) ?
 365                       skb_transport_offset(skb) :
 366                       skb_network_offset(skb)) +
 367                      parms->tcfp_off_max_hint;
 368         if (skb_ensure_writable(skb, min(skb->len, max_offset)))
 369                 goto done;
 370
 371         tcf_lastuse_update(&p->tcf_tm);
 372         tcf_action_update_bstats(&p->common, skb);
 373
 374         tkey = parms->tcfp_keys;
 375         tkey_ex = parms->tcfp_keys_ex;
 376
 377         for (i = parms->tcfp_nkeys; i > 0; i--, tkey++) {
 378                 int offset = tkey->off;
 379                 u32 *ptr, hdata;
 380                 int hoffset;
 381                 u32 val;
 382                 int rc;
 383
 384                 if (tkey_ex) {
 385                         htype = tkey_ex->htype;
 386                         cmd = tkey_ex->cmd;
 387
 388                         tkey_ex++;
 389                 }
 390
 391                 rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 392                 if (rc) {
 393                         pr_info("tc action pedit bad header type specified (0x%x)\n",
 394                                 htype);
 395                         goto bad;
 396                 }
 397
 398                 if (tkey->offmask) {
 399                         u8 *d, _d;
 400
 401                         if (!offset_valid(skb, hoffset + tkey->at)) {
 402                                 pr_info("tc action pedit 'at' offset %d out of bounds\n",
 403                                         hoffset + tkey->at);
 404                                 goto bad;
 405                         }
 406                         d = skb_header_pointer(skb, hoffset + tkey->at,
 407                                                sizeof(_d), &_d);
 408                         if (!d)
 409                                 goto bad;
 410                         offset += (*d & tkey->offmask) >> tkey->shift;
 411                 }
 412
 413                 if (offset % 4) {
 414                         pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 415                         goto bad;
 416                 }
 417
 418                 if (!offset_valid(skb, hoffset + offset)) {
 419                         pr_info("tc action pedit offset %d out of bounds\n",
 420                                 hoffset + offset);
 421                         goto bad;
 422                 }
 423
 424                 ptr = skb_header_pointer(skb, hoffset + offset,
 425                                          sizeof(hdata), &hdata);
 426                 if (!ptr)
 427                         goto bad;
 428                 /* just do it, baby */
 429                 switch (cmd) {
 430                 case TCA_PEDIT_KEY_EX_CMD_SET:
 431                         val = tkey->val;
 432                         break;
 433                 case TCA_PEDIT_KEY_EX_CMD_ADD:
 434                         val = (*ptr + tkey->val) & ~tkey->mask;
 435                         break;
 436                 default:
 437                         pr_info("tc action pedit bad command (%d)\n",
 438                                 cmd);
 439                         goto bad;
 440                 }
 441
 442                 *ptr = ((*ptr & tkey->mask) ^ val);
 443                 if (ptr == &hdata)
 444                         skb_store_bits(skb, hoffset + offset, ptr, 4);
 445         }
 446
 447         goto done;
 448
 449 bad:
 450         tcf_action_inc_overlimit_qstats(&p->common);
 451 done:
 452         return p->tcf_action;
 453 }
 454
 455 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
 456                                    u64 drops, u64 lastuse, bool hw)
 457 {
 458         struct tcf_pedit *d = to_pedit(a);
 459         struct tcf_t *tm = &d->tcf_tm;
 460
 461         tcf_action_update_stats(a, bytes, packets, drops, hw);
 462         tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 463 }
 464
 465 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 466                           int bind, int ref)
 467 {
 468         unsigned char *b = skb_tail_pointer(skb);
 469         struct tcf_pedit *p = to_pedit(a);
 470         struct tcf_pedit_parms *parms;
 471         struct tc_pedit *opt;
 472         struct tcf_t t;
 473         int s;
 474
 475         spin_lock_bh(&p->tcf_lock);
 476         parms = rcu_dereference_protected(p->parms, 1);
 477         s = struct_size(opt, keys, parms->tcfp_nkeys);
 478
 479         opt = kzalloc(s, GFP_ATOMIC);
 480         if (unlikely(!opt)) {
 481                 spin_unlock_bh(&p->tcf_lock);
 482                 return -ENOBUFS;
 483         }
 484
 485         memcpy(opt->keys, parms->tcfp_keys,
 486                flex_array_size(opt, keys, parms->tcfp_nkeys));
 487         opt->index = p->tcf_index;
 488         opt->nkeys = parms->tcfp_nkeys;
 489         opt->flags = parms->tcfp_flags;
 490         opt->action = p->tcf_action;
 491         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 492         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 493
 494         if (parms->tcfp_keys_ex) {
 495                 if (tcf_pedit_key_ex_dump(skb, parms->tcfp_keys_ex,
 496                                           parms->tcfp_nkeys))
 497                         goto nla_put_failure;
 498
 499                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 500                         goto nla_put_failure;
 501         } else {
 502                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 503                         goto nla_put_failure;
 504         }
 505
 506         tcf_tm_dump(&t, &p->tcf_tm);
 507         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 508                 goto nla_put_failure;
 509         spin_unlock_bh(&p->tcf_lock);
 510
 511         kfree(opt);
 512         return skb->len;
 513
 514 nla_put_failure:
 515         spin_unlock_bh(&p->tcf_lock);
 516         nlmsg_trim(skb, b);
 517         kfree(opt);
 518         return -1;
 519 }
 520
 521 static int tcf_pedit_offload_act_setup(struct tc_action *act, void *entry_data,
 522                                        u32 *index_inc, bool bind,
 523                                        struct netlink_ext_ack *extack)
 524 {
 525         if (bind) {
 526                 struct flow_action_entry *entry = entry_data;
 527                 int k;
 528
 529                 for (k = 0; k < tcf_pedit_nkeys(act); k++) {
 530                         switch (tcf_pedit_cmd(act, k)) {
 531                         case TCA_PEDIT_KEY_EX_CMD_SET:
 532                                 entry->id = FLOW_ACTION_MANGLE;
 533                                 break;
 534                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 535                                 entry->id = FLOW_ACTION_ADD;
 536                                 break;
 537                         default:
 538                                 NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 539                                 return -EOPNOTSUPP;
 540                         }
 541                         entry->mangle.htype = tcf_pedit_htype(act, k);
 542                         entry->mangle.mask = tcf_pedit_mask(act, k);
 543                         entry->mangle.val = tcf_pedit_val(act, k);
 544                         entry->mangle.offset = tcf_pedit_offset(act, k);
 545                         entry->hw_stats = tc_act_hw_stats(act->hw_stats);
 546                         entry++;
 547                 }
 548                 *index_inc = k;
 549         } else {
 550                 struct flow_offload_action *fl_action = entry_data;
 551                 u32 cmd = tcf_pedit_cmd(act, 0);
 552                 int k;
 553
 554                 switch (cmd) {
 555                 case TCA_PEDIT_KEY_EX_CMD_SET:
 556                         fl_action->id = FLOW_ACTION_MANGLE;
 557                         break;
 558                 case TCA_PEDIT_KEY_EX_CMD_ADD:
 559                         fl_action->id = FLOW_ACTION_ADD;
 560                         break;
 561                 default:
 562                         NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 563                         return -EOPNOTSUPP;
 564                 }
 565
 566                 for (k = 1; k < tcf_pedit_nkeys(act); k++) {
 567                         if (cmd != tcf_pedit_cmd(act, k)) {
 568                                 NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
 569                                 return -EOPNOTSUPP;
 570                         }
 571                 }
 572         }
 573
 574         return 0;
 575 }
 576
 577 static struct tc_action_ops act_pedit_ops = {
 578         .kind           =       "pedit",
 579         .id             =       TCA_ID_PEDIT,
 580         .owner          =       THIS_MODULE,
 581         .act            =       tcf_pedit_act,
 582         .stats_update   =       tcf_pedit_stats_update,
 583         .dump           =       tcf_pedit_dump,
 584         .cleanup        =       tcf_pedit_cleanup,
 585         .init           =       tcf_pedit_init,
 586         .offload_act_setup =    tcf_pedit_offload_act_setup,
 587         .size           =       sizeof(struct tcf_pedit),
 588 };
 589
 590 static __net_init int pedit_init_net(struct net *net)
 591 {
 592         struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
 593
 594         return tc_action_net_init(net, tn, &act_pedit_ops);
 595 }
 596
 597 static void __net_exit pedit_exit_net(struct list_head *net_list)
 598 {
 599         tc_action_net_exit(net_list, act_pedit_ops.net_id);
 600 }
 601
 602 static struct pernet_operations pedit_net_ops = {
 603         .init = pedit_init_net,
 604         .exit_batch = pedit_exit_net,
 605         .id   = &act_pedit_ops.net_id,
 606         .size = sizeof(struct tc_action_net),
 607 };
 608
 609 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 610 MODULE_DESCRIPTION("Generic Packet Editor actions");
 611 MODULE_LICENSE("GPL");
 612
 613 static int __init pedit_init_module(void)
 614 {
 615         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 616 }
 617
 618 static void __exit pedit_cleanup_module(void)
 619 {
 620         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 621 }
 622
 623 module_init(pedit_init_module);
 624 module_exit(pedit_cleanup_module);