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