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)
  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, u32 flags,
 141                           struct netlink_ext_ack *extack)
 142 {
 143         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 144         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 145         struct tcf_chain *goto_ch = NULL;
 146         struct tc_pedit_key *keys = NULL;
 147         struct tcf_pedit_key_ex *keys_ex;
 148         struct tc_pedit *parm;
 149         struct nlattr *pattr;
 150         struct tcf_pedit *p;
 151         int ret = 0, err;
 152         int ksize;
 153         u32 index;
 154
 155         if (!nla) {
 156                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 157                 return -EINVAL;
 158         }
 159
 160         err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 161                                           pedit_policy, NULL);
 162         if (err < 0)
 163                 return err;
 164
 165         pattr = tb[TCA_PEDIT_PARMS];
 166         if (!pattr)
 167                 pattr = tb[TCA_PEDIT_PARMS_EX];
 168         if (!pattr) {
 169                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 170                 return -EINVAL;
 171         }
 172
 173         parm = nla_data(pattr);
 174         if (!parm->nkeys) {
 175                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 176                 return -EINVAL;
 177         }
 178         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 179         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 180                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 181                 return -EINVAL;
 182         }
 183
 184         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 185         if (IS_ERR(keys_ex))
 186                 return PTR_ERR(keys_ex);
 187
 188         index = parm->index;
 189         err = tcf_idr_check_alloc(tn, &index, a, bind);
 190         if (!err) {
 191                 ret = tcf_idr_create(tn, index, est, a,
 192                                      &act_pedit_ops, bind, false, 0);
 193                 if (ret) {
 194                         tcf_idr_cleanup(tn, index);
 195                         goto out_free;
 196                 }
 197                 ret = ACT_P_CREATED;
 198         } else if (err > 0) {
 199                 if (bind)
 200                         goto out_free;
 201                 if (!ovr) {
 202                         ret = -EEXIST;
 203                         goto out_release;
 204                 }
 205         } else {
 206                 ret = err;
 207                 goto out_free;
 208         }
 209
 210         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 211         if (err < 0) {
 212                 ret = err;
 213                 goto out_release;
 214         }
 215         p = to_pedit(*a);
 216         spin_lock_bh(&p->tcf_lock);
 217
 218         if (ret == ACT_P_CREATED ||
 219             (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 220                 keys = kmalloc(ksize, GFP_ATOMIC);
 221                 if (!keys) {
 222                         spin_unlock_bh(&p->tcf_lock);
 223                         ret = -ENOMEM;
 224                         goto put_chain;
 225                 }
 226                 kfree(p->tcfp_keys);
 227                 p->tcfp_keys = keys;
 228                 p->tcfp_nkeys = parm->nkeys;
 229         }
 230         memcpy(p->tcfp_keys, parm->keys, ksize);
 231
 232         p->tcfp_flags = parm->flags;
 233         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 234
 235         kfree(p->tcfp_keys_ex);
 236         p->tcfp_keys_ex = keys_ex;
 237
 238         spin_unlock_bh(&p->tcf_lock);
 239         if (goto_ch)
 240                 tcf_chain_put_by_act(goto_ch);
 241         if (ret == ACT_P_CREATED)
 242                 tcf_idr_insert(tn, *a);
 243         return ret;
 244
 245 put_chain:
 246         if (goto_ch)
 247                 tcf_chain_put_by_act(goto_ch);
 248 out_release:
 249         tcf_idr_release(*a, bind);
 250 out_free:
 251         kfree(keys_ex);
 252         return ret;
 253
 254 }
 255
 256 static void tcf_pedit_cleanup(struct tc_action *a)
 257 {
 258         struct tcf_pedit *p = to_pedit(a);
 259         struct tc_pedit_key *keys = p->tcfp_keys;
 260
 261         kfree(keys);
 262         kfree(p->tcfp_keys_ex);
 263 }
 264
 265 static bool offset_valid(struct sk_buff *skb, int offset)
 266 {
 267         if (offset > 0 && offset > skb->len)
 268                 return false;
 269
 270         if  (offset < 0 && -offset > skb_headroom(skb))
 271                 return false;
 272
 273         return true;
 274 }
 275
 276 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 277                                 enum pedit_header_type htype, int *hoffset)
 278 {
 279         int ret = -EINVAL;
 280
 281         switch (htype) {
 282         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 283                 if (skb_mac_header_was_set(skb)) {
 284                         *hoffset = skb_mac_offset(skb);
 285                         ret = 0;
 286                 }
 287                 break;
 288         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 289         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 290         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 291                 *hoffset = skb_network_offset(skb);
 292                 ret = 0;
 293                 break;
 294         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 295         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 296                 if (skb_transport_header_was_set(skb)) {
 297                         *hoffset = skb_transport_offset(skb);
 298                         ret = 0;
 299                 }
 300                 break;
 301         default:
 302                 ret = -EINVAL;
 303                 break;
 304         }
 305
 306         return ret;
 307 }
 308
 309 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 310                          struct tcf_result *res)
 311 {
 312         struct tcf_pedit *p = to_pedit(a);
 313         int i;
 314
 315         if (skb_unclone(skb, GFP_ATOMIC))
 316                 return p->tcf_action;
 317
 318         spin_lock(&p->tcf_lock);
 319
 320         tcf_lastuse_update(&p->tcf_tm);
 321
 322         if (p->tcfp_nkeys > 0) {
 323                 struct tc_pedit_key *tkey = p->tcfp_keys;
 324                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 325                 enum pedit_header_type htype =
 326                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 327                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 328
 329                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 330                         u32 *ptr, hdata;
 331                         int offset = tkey->off;
 332                         int hoffset;
 333                         u32 val;
 334                         int rc;
 335
 336                         if (tkey_ex) {
 337                                 htype = tkey_ex->htype;
 338                                 cmd = tkey_ex->cmd;
 339
 340                                 tkey_ex++;
 341                         }
 342
 343                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 344                         if (rc) {
 345                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 346                                         htype);
 347                                 goto bad;
 348                         }
 349
 350                         if (tkey->offmask) {
 351                                 u8 *d, _d;
 352
 353                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 354                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 355                                                 hoffset + tkey->at);
 356                                         goto bad;
 357                                 }
 358                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 359                                                        sizeof(_d), &_d);
 360                                 if (!d)
 361                                         goto bad;
 362                                 offset += (*d & tkey->offmask) >> tkey->shift;
 363                         }
 364
 365                         if (offset % 4) {
 366                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 367                                 goto bad;
 368                         }
 369
 370                         if (!offset_valid(skb, hoffset + offset)) {
 371                                 pr_info("tc action pedit offset %d out of bounds\n",
 372                                         hoffset + offset);
 373                                 goto bad;
 374                         }
 375
 376                         ptr = skb_header_pointer(skb, hoffset + offset,
 377                                                  sizeof(hdata), &hdata);
 378                         if (!ptr)
 379                                 goto bad;
 380                         /* just do it, baby */
 381                         switch (cmd) {
 382                         case TCA_PEDIT_KEY_EX_CMD_SET:
 383                                 val = tkey->val;
 384                                 break;
 385                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 386                                 val = (*ptr + tkey->val) & ~tkey->mask;
 387                                 break;
 388                         default:
 389                                 pr_info("tc action pedit bad command (%d)\n",
 390                                         cmd);
 391                                 goto bad;
 392                         }
 393
 394                         *ptr = ((*ptr & tkey->mask) ^ val);
 395                         if (ptr == &hdata)
 396                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 397                 }
 398
 399                 goto done;
 400         } else {
 401                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 402         }
 403
 404 bad:
 405         p->tcf_qstats.overlimits++;
 406 done:
 407         bstats_update(&p->tcf_bstats, skb);
 408         spin_unlock(&p->tcf_lock);
 409         return p->tcf_action;
 410 }
 411
 412 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 413                           int bind, int ref)
 414 {
 415         unsigned char *b = skb_tail_pointer(skb);
 416         struct tcf_pedit *p = to_pedit(a);
 417         struct tc_pedit *opt;
 418         struct tcf_t t;
 419         int s;
 420
 421         s = struct_size(opt, keys, p->tcfp_nkeys);
 422
 423         /* netlink spinlocks held above us - must use ATOMIC */
 424         opt = kzalloc(s, GFP_ATOMIC);
 425         if (unlikely(!opt))
 426                 return -ENOBUFS;
 427
 428         spin_lock_bh(&p->tcf_lock);
 429         memcpy(opt->keys, p->tcfp_keys,
 430                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 431         opt->index = p->tcf_index;
 432         opt->nkeys = p->tcfp_nkeys;
 433         opt->flags = p->tcfp_flags;
 434         opt->action = p->tcf_action;
 435         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 436         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 437
 438         if (p->tcfp_keys_ex) {
 439                 if (tcf_pedit_key_ex_dump(skb,
 440                                           p->tcfp_keys_ex,
 441                                           p->tcfp_nkeys))
 442                         goto nla_put_failure;
 443
 444                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 445                         goto nla_put_failure;
 446         } else {
 447                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 448                         goto nla_put_failure;
 449         }
 450
 451         tcf_tm_dump(&t, &p->tcf_tm);
 452         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 453                 goto nla_put_failure;
 454         spin_unlock_bh(&p->tcf_lock);
 455
 456         kfree(opt);
 457         return skb->len;
 458
 459 nla_put_failure:
 460         spin_unlock_bh(&p->tcf_lock);
 461         nlmsg_trim(skb, b);
 462         kfree(opt);
 463         return -1;
 464 }
 465
 466 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 467                             struct netlink_callback *cb, int type,
 468                             const struct tc_action_ops *ops,
 469                             struct netlink_ext_ack *extack)
 470 {
 471         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 472
 473         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 474 }
 475
 476 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 477 {
 478         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 479
 480         return tcf_idr_search(tn, a, index);
 481 }
 482
 483 static struct tc_action_ops act_pedit_ops = {
 484         .kind           =       "pedit",
 485         .id             =       TCA_ID_PEDIT,
 486         .owner          =       THIS_MODULE,
 487         .act            =       tcf_pedit_act,
 488         .dump           =       tcf_pedit_dump,
 489         .cleanup        =       tcf_pedit_cleanup,
 490         .init           =       tcf_pedit_init,
 491         .walk           =       tcf_pedit_walker,
 492         .lookup         =       tcf_pedit_search,
 493         .size           =       sizeof(struct tcf_pedit),
 494 };
 495
 496 static __net_init int pedit_init_net(struct net *net)
 497 {
 498         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 499
 500         return tc_action_net_init(net, tn, &act_pedit_ops);
 501 }
 502
 503 static void __net_exit pedit_exit_net(struct list_head *net_list)
 504 {
 505         tc_action_net_exit(net_list, pedit_net_id);
 506 }
 507
 508 static struct pernet_operations pedit_net_ops = {
 509         .init = pedit_init_net,
 510         .exit_batch = pedit_exit_net,
 511         .id   = &pedit_net_id,
 512         .size = sizeof(struct tc_action_net),
 513 };
 514
 515 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 516 MODULE_DESCRIPTION("Generic Packet Editor actions");
 517 MODULE_LICENSE("GPL");
 518
 519 static int __init pedit_init_module(void)
 520 {
 521         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 522 }
 523
 524 static void __exit pedit_cleanup_module(void)
 525 {
 526         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 527 }
 528
 529 module_init(pedit_init_module);
 530 module_exit(pedit_cleanup_module);