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_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 || !n)
  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 int tcf_pedit_init(struct net *net, struct nlattr *nla,
 138                           struct nlattr *est, struct tc_action **a,
 139                           int ovr, int bind, bool rtnl_held,
 140                           struct tcf_proto *tp, struct netlink_ext_ack *extack)
 141 {
 142         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 143         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 144         struct tcf_chain *goto_ch = NULL;
 145         struct tc_pedit_key *keys = NULL;
 146         struct tcf_pedit_key_ex *keys_ex;
 147         struct tc_pedit *parm;
 148         struct nlattr *pattr;
 149         struct tcf_pedit *p;
 150         int ret = 0, err;
 151         int ksize;
 152         u32 index;
 153
 154         if (!nla) {
 155                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 156                 return -EINVAL;
 157         }
 158
 159         err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 160                                           pedit_policy, NULL);
 161         if (err < 0)
 162                 return err;
 163
 164         pattr = tb[TCA_PEDIT_PARMS];
 165         if (!pattr)
 166                 pattr = tb[TCA_PEDIT_PARMS_EX];
 167         if (!pattr) {
 168                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 169                 return -EINVAL;
 170         }
 171
 172         parm = nla_data(pattr);
 173         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 174         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 175                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 176                 return -EINVAL;
 177         }
 178
 179         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 180         if (IS_ERR(keys_ex))
 181                 return PTR_ERR(keys_ex);
 182
 183         index = parm->index;
 184         err = tcf_idr_check_alloc(tn, &index, a, bind);
 185         if (!err) {
 186                 if (!parm->nkeys) {
 187                         tcf_idr_cleanup(tn, index);
 188                         NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 189                         ret = -EINVAL;
 190                         goto out_free;
 191                 }
 192                 ret = tcf_idr_create(tn, index, est, a,
 193                                      &act_pedit_ops, bind, false);
 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
 233         p->tcfp_flags = parm->flags;
 234         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 235
 236         kfree(p->tcfp_keys_ex);
 237         p->tcfp_keys_ex = keys_ex;
 238
 239         spin_unlock_bh(&p->tcf_lock);
 240         if (goto_ch)
 241                 tcf_chain_put_by_act(goto_ch);
 242         if (ret == ACT_P_CREATED)
 243                 tcf_idr_insert(tn, *a);
 244         return ret;
 245
 246 put_chain:
 247         if (goto_ch)
 248                 tcf_chain_put_by_act(goto_ch);
 249 out_release:
 250         tcf_idr_release(*a, bind);
 251 out_free:
 252         kfree(keys_ex);
 253         return ret;
 254
 255 }
 256
 257 static void tcf_pedit_cleanup(struct tc_action *a)
 258 {
 259         struct tcf_pedit *p = to_pedit(a);
 260         struct tc_pedit_key *keys = p->tcfp_keys;
 261
 262         kfree(keys);
 263         kfree(p->tcfp_keys_ex);
 264 }
 265
 266 static bool offset_valid(struct sk_buff *skb, int offset)
 267 {
 268         if (offset > 0 && offset > skb->len)
 269                 return false;
 270
 271         if  (offset < 0 && -offset > skb_headroom(skb))
 272                 return false;
 273
 274         return true;
 275 }
 276
 277 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 278                                 enum pedit_header_type htype, int *hoffset)
 279 {
 280         int ret = -EINVAL;
 281
 282         switch (htype) {
 283         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 284                 if (skb_mac_header_was_set(skb)) {
 285                         *hoffset = skb_mac_offset(skb);
 286                         ret = 0;
 287                 }
 288                 break;
 289         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 290         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 291         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 292                 *hoffset = skb_network_offset(skb);
 293                 ret = 0;
 294                 break;
 295         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 296         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 297                 if (skb_transport_header_was_set(skb)) {
 298                         *hoffset = skb_transport_offset(skb);
 299                         ret = 0;
 300                 }
 301                 break;
 302         default:
 303                 ret = -EINVAL;
 304                 break;
 305         }
 306
 307         return ret;
 308 }
 309
 310 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 311                          struct tcf_result *res)
 312 {
 313         struct tcf_pedit *p = to_pedit(a);
 314         int i;
 315
 316         if (skb_unclone(skb, GFP_ATOMIC))
 317                 return p->tcf_action;
 318
 319         spin_lock(&p->tcf_lock);
 320
 321         tcf_lastuse_update(&p->tcf_tm);
 322
 323         if (p->tcfp_nkeys > 0) {
 324                 struct tc_pedit_key *tkey = p->tcfp_keys;
 325                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 326                 enum pedit_header_type htype =
 327                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 328                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 329
 330                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 331                         u32 *ptr, hdata;
 332                         int offset = tkey->off;
 333                         int hoffset;
 334                         u32 val;
 335                         int rc;
 336
 337                         if (tkey_ex) {
 338                                 htype = tkey_ex->htype;
 339                                 cmd = tkey_ex->cmd;
 340
 341                                 tkey_ex++;
 342                         }
 343
 344                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 345                         if (rc) {
 346                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 347                                         htype);
 348                                 goto bad;
 349                         }
 350
 351                         if (tkey->offmask) {
 352                                 u8 *d, _d;
 353
 354                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 355                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 356                                                 hoffset + tkey->at);
 357                                         goto bad;
 358                                 }
 359                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 360                                                        sizeof(_d), &_d);
 361                                 if (!d)
 362                                         goto bad;
 363                                 offset += (*d & tkey->offmask) >> tkey->shift;
 364                         }
 365
 366                         if (offset % 4) {
 367                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 368                                 goto bad;
 369                         }
 370
 371                         if (!offset_valid(skb, hoffset + offset)) {
 372                                 pr_info("tc action pedit offset %d out of bounds\n",
 373                                         hoffset + offset);
 374                                 goto bad;
 375                         }
 376
 377                         ptr = skb_header_pointer(skb, hoffset + offset,
 378                                                  sizeof(hdata), &hdata);
 379                         if (!ptr)
 380                                 goto bad;
 381                         /* just do it, baby */
 382                         switch (cmd) {
 383                         case TCA_PEDIT_KEY_EX_CMD_SET:
 384                                 val = tkey->val;
 385                                 break;
 386                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 387                                 val = (*ptr + tkey->val) & ~tkey->mask;
 388                                 break;
 389                         default:
 390                                 pr_info("tc action pedit bad command (%d)\n",
 391                                         cmd);
 392                                 goto bad;
 393                         }
 394
 395                         *ptr = ((*ptr & tkey->mask) ^ val);
 396                         if (ptr == &hdata)
 397                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 398                 }
 399
 400                 goto done;
 401         } else {
 402                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 403         }
 404
 405 bad:
 406         p->tcf_qstats.overlimits++;
 407 done:
 408         bstats_update(&p->tcf_bstats, skb);
 409         spin_unlock(&p->tcf_lock);
 410         return p->tcf_action;
 411 }
 412
 413 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 414                           int bind, int ref)
 415 {
 416         unsigned char *b = skb_tail_pointer(skb);
 417         struct tcf_pedit *p = to_pedit(a);
 418         struct tc_pedit *opt;
 419         struct tcf_t t;
 420         int s;
 421
 422         s = struct_size(opt, keys, p->tcfp_nkeys);
 423
 424         /* netlink spinlocks held above us - must use ATOMIC */
 425         opt = kzalloc(s, GFP_ATOMIC);
 426         if (unlikely(!opt))
 427                 return -ENOBUFS;
 428
 429         spin_lock_bh(&p->tcf_lock);
 430         memcpy(opt->keys, p->tcfp_keys,
 431                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 432         opt->index = p->tcf_index;
 433         opt->nkeys = p->tcfp_nkeys;
 434         opt->flags = p->tcfp_flags;
 435         opt->action = p->tcf_action;
 436         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 437         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 438
 439         if (p->tcfp_keys_ex) {
 440                 if (tcf_pedit_key_ex_dump(skb,
 441                                           p->tcfp_keys_ex,
 442                                           p->tcfp_nkeys))
 443                         goto nla_put_failure;
 444
 445                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 446                         goto nla_put_failure;
 447         } else {
 448                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 449                         goto nla_put_failure;
 450         }
 451
 452         tcf_tm_dump(&t, &p->tcf_tm);
 453         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 454                 goto nla_put_failure;
 455         spin_unlock_bh(&p->tcf_lock);
 456
 457         kfree(opt);
 458         return skb->len;
 459
 460 nla_put_failure:
 461         spin_unlock_bh(&p->tcf_lock);
 462         nlmsg_trim(skb, b);
 463         kfree(opt);
 464         return -1;
 465 }
 466
 467 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 468                             struct netlink_callback *cb, int type,
 469                             const struct tc_action_ops *ops,
 470                             struct netlink_ext_ack *extack)
 471 {
 472         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 473
 474         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 475 }
 476
 477 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 478 {
 479         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 480
 481         return tcf_idr_search(tn, a, index);
 482 }
 483
 484 static struct tc_action_ops act_pedit_ops = {
 485         .kind           =       "pedit",
 486         .id             =       TCA_ID_PEDIT,
 487         .owner          =       THIS_MODULE,
 488         .act            =       tcf_pedit_act,
 489         .dump           =       tcf_pedit_dump,
 490         .cleanup        =       tcf_pedit_cleanup,
 491         .init           =       tcf_pedit_init,
 492         .walk           =       tcf_pedit_walker,
 493         .lookup         =       tcf_pedit_search,
 494         .size           =       sizeof(struct tcf_pedit),
 495 };
 496
 497 static __net_init int pedit_init_net(struct net *net)
 498 {
 499         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 500
 501         return tc_action_net_init(net, tn, &act_pedit_ops);
 502 }
 503
 504 static void __net_exit pedit_exit_net(struct list_head *net_list)
 505 {
 506         tc_action_net_exit(net_list, pedit_net_id);
 507 }
 508
 509 static struct pernet_operations pedit_net_ops = {
 510         .init = pedit_init_net,
 511         .exit_batch = pedit_exit_net,
 512         .id   = &pedit_net_id,
 513         .size = sizeof(struct tc_action_net),
 514 };
 515
 516 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 517 MODULE_DESCRIPTION("Generic Packet Editor actions");
 518 MODULE_LICENSE("GPL");
 519
 520 static int __init pedit_init_module(void)
 521 {
 522         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 523 }
 524
 525 static void __exit pedit_cleanup_module(void)
 526 {
 527         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 528 }
 529
 530 module_init(pedit_init_module);
 531 module_exit(pedit_cleanup_module);