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