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