net/sched/act_pedit.c

   1 /*
   2  * net/sched/act_pedit.c        Generic packet editor
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Jamal Hadi Salim (2002-4)
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/errno.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <linux/tc_act/tc_pedit.h>
  24 #include <net/tc_act/tc_pedit.h>
  25 #include <uapi/linux/tc_act/tc_pedit.h>
  26
  27 static unsigned int pedit_net_id;
  28 static struct tc_action_ops act_pedit_ops;
  29
  30 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  31         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  32         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  33 };
  34
  35 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  36         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  37         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  38 };
  39
  40 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  41                                                         u8 n)
  42 {
  43         struct tcf_pedit_key_ex *keys_ex;
  44         struct tcf_pedit_key_ex *k;
  45         const struct nlattr *ka;
  46         int err = -EINVAL;
  47         int rem;
  48
  49         if (!nla || !n)
  50                 return NULL;
  51
  52         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  53         if (!keys_ex)
  54                 return ERR_PTR(-ENOMEM);
  55
  56         k = keys_ex;
  57
  58         nla_for_each_nested(ka, nla, rem) {
  59                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  60
  61                 if (!n) {
  62                         err = -EINVAL;
  63                         goto err_out;
  64                 }
  65                 n--;
  66
  67                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  68                         err = -EINVAL;
  69                         goto err_out;
  70                 }
  71
  72                 err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
  73                                        pedit_key_ex_policy, NULL);
  74                 if (err)
  75                         goto err_out;
  76
  77                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  78                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  79                         err = -EINVAL;
  80                         goto err_out;
  81                 }
  82
  83                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  84                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  85
  86                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  87                     k->cmd > TCA_PEDIT_CMD_MAX) {
  88                         err = -EINVAL;
  89                         goto err_out;
  90                 }
  91
  92                 k++;
  93         }
  94
  95         if (n) {
  96                 err = -EINVAL;
  97                 goto err_out;
  98         }
  99
 100         return keys_ex;
 101
 102 err_out:
 103         kfree(keys_ex);
 104         return ERR_PTR(err);
 105 }
 106
 107 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 108                                  struct tcf_pedit_key_ex *keys_ex, int n)
 109 {
 110         struct nlattr *keys_start = nla_nest_start(skb, 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(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 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 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(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
 159         if (err < 0)
 160                 return err;
 161
 162         pattr = tb[TCA_PEDIT_PARMS];
 163         if (!pattr)
 164                 pattr = tb[TCA_PEDIT_PARMS_EX];
 165         if (!pattr) {
 166                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 167                 return -EINVAL;
 168         }
 169
 170         parm = nla_data(pattr);
 171         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 172         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 173                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 174                 return -EINVAL;
 175         }
 176
 177         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 178         if (IS_ERR(keys_ex))
 179                 return PTR_ERR(keys_ex);
 180
 181         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 182         if (!err) {
 183                 if (!parm->nkeys) {
 184                         tcf_idr_cleanup(tn, parm->index);
 185                         NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 186                         ret = -EINVAL;
 187                         goto out_free;
 188                 }
 189                 ret = tcf_idr_create(tn, parm->index, est, a,
 190                                      &act_pedit_ops, bind, false);
 191                 if (ret) {
 192                         tcf_idr_cleanup(tn, parm->index);
 193                         goto out_free;
 194                 }
 195                 ret = ACT_P_CREATED;
 196         } else if (err > 0) {
 197                 if (bind)
 198                         goto out_free;
 199                 if (!ovr) {
 200                         ret = -EEXIST;
 201                         goto out_release;
 202                 }
 203         } else {
 204                 return err;
 205         }
 206
 207         p = to_pedit(*a);
 208         spin_lock_bh(&p->tcf_lock);
 209
 210         if (ret == ACT_P_CREATED ||
 211             (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 212                 keys = kmalloc(ksize, GFP_ATOMIC);
 213                 if (!keys) {
 214                         spin_unlock_bh(&p->tcf_lock);
 215                         ret = -ENOMEM;
 216                         goto out_release;
 217                 }
 218                 kfree(p->tcfp_keys);
 219                 p->tcfp_keys = keys;
 220                 p->tcfp_nkeys = parm->nkeys;
 221         }
 222         memcpy(p->tcfp_keys, parm->keys, ksize);
 223
 224         p->tcfp_flags = parm->flags;
 225         p->tcf_action = parm->action;
 226
 227         kfree(p->tcfp_keys_ex);
 228         p->tcfp_keys_ex = keys_ex;
 229
 230         spin_unlock_bh(&p->tcf_lock);
 231         if (ret == ACT_P_CREATED)
 232                 tcf_idr_insert(tn, *a);
 233         return ret;
 234
 235 out_release:
 236         tcf_idr_release(*a, bind);
 237 out_free:
 238         kfree(keys_ex);
 239         return ret;
 240
 241 }
 242
 243 static void tcf_pedit_cleanup(struct tc_action *a)
 244 {
 245         struct tcf_pedit *p = to_pedit(a);
 246         struct tc_pedit_key *keys = p->tcfp_keys;
 247
 248         kfree(keys);
 249         kfree(p->tcfp_keys_ex);
 250 }
 251
 252 static bool offset_valid(struct sk_buff *skb, int offset)
 253 {
 254         if (offset > 0 && offset > skb->len)
 255                 return false;
 256
 257         if  (offset < 0 && -offset > skb_headroom(skb))
 258                 return false;
 259
 260         return true;
 261 }
 262
 263 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 264                                 enum pedit_header_type htype, int *hoffset)
 265 {
 266         int ret = -EINVAL;
 267
 268         switch (htype) {
 269         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 270                 if (skb_mac_header_was_set(skb)) {
 271                         *hoffset = skb_mac_offset(skb);
 272                         ret = 0;
 273                 }
 274                 break;
 275         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 276         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 277         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 278                 *hoffset = skb_network_offset(skb);
 279                 ret = 0;
 280                 break;
 281         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 282         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 283                 if (skb_transport_header_was_set(skb)) {
 284                         *hoffset = skb_transport_offset(skb);
 285                         ret = 0;
 286                 }
 287                 break;
 288         default:
 289                 ret = -EINVAL;
 290                 break;
 291         }
 292
 293         return ret;
 294 }
 295
 296 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 297                          struct tcf_result *res)
 298 {
 299         struct tcf_pedit *p = to_pedit(a);
 300         int i;
 301
 302         if (skb_unclone(skb, GFP_ATOMIC))
 303                 return p->tcf_action;
 304
 305         spin_lock(&p->tcf_lock);
 306
 307         tcf_lastuse_update(&p->tcf_tm);
 308
 309         if (p->tcfp_nkeys > 0) {
 310                 struct tc_pedit_key *tkey = p->tcfp_keys;
 311                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 312                 enum pedit_header_type htype =
 313                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 314                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 315
 316                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 317                         u32 *ptr, hdata;
 318                         int offset = tkey->off;
 319                         int hoffset;
 320                         u32 val;
 321                         int rc;
 322
 323                         if (tkey_ex) {
 324                                 htype = tkey_ex->htype;
 325                                 cmd = tkey_ex->cmd;
 326
 327                                 tkey_ex++;
 328                         }
 329
 330                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 331                         if (rc) {
 332                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 333                                         htype);
 334                                 goto bad;
 335                         }
 336
 337                         if (tkey->offmask) {
 338                                 u8 *d, _d;
 339
 340                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 341                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 342                                                 hoffset + tkey->at);
 343                                         goto bad;
 344                                 }
 345                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 346                                                        sizeof(_d), &_d);
 347                                 if (!d)
 348                                         goto bad;
 349                                 offset += (*d & tkey->offmask) >> tkey->shift;
 350                         }
 351
 352                         if (offset % 4) {
 353                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 354                                 goto bad;
 355                         }
 356
 357                         if (!offset_valid(skb, hoffset + offset)) {
 358                                 pr_info("tc action pedit offset %d out of bounds\n",
 359                                         hoffset + offset);
 360                                 goto bad;
 361                         }
 362
 363                         ptr = skb_header_pointer(skb, hoffset + offset,
 364                                                  sizeof(hdata), &hdata);
 365                         if (!ptr)
 366                                 goto bad;
 367                         /* just do it, baby */
 368                         switch (cmd) {
 369                         case TCA_PEDIT_KEY_EX_CMD_SET:
 370                                 val = tkey->val;
 371                                 break;
 372                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 373                                 val = (*ptr + tkey->val) & ~tkey->mask;
 374                                 break;
 375                         default:
 376                                 pr_info("tc action pedit bad command (%d)\n",
 377                                         cmd);
 378                                 goto bad;
 379                         }
 380
 381                         *ptr = ((*ptr & tkey->mask) ^ val);
 382                         if (ptr == &hdata)
 383                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 384                 }
 385
 386                 goto done;
 387         } else {
 388                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 389         }
 390
 391 bad:
 392         p->tcf_qstats.overlimits++;
 393 done:
 394         bstats_update(&p->tcf_bstats, skb);
 395         spin_unlock(&p->tcf_lock);
 396         return p->tcf_action;
 397 }
 398
 399 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 400                           int bind, int ref)
 401 {
 402         unsigned char *b = skb_tail_pointer(skb);
 403         struct tcf_pedit *p = to_pedit(a);
 404         struct tc_pedit *opt;
 405         struct tcf_t t;
 406         int s;
 407
 408         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 409
 410         /* netlink spinlocks held above us - must use ATOMIC */
 411         opt = kzalloc(s, GFP_ATOMIC);
 412         if (unlikely(!opt))
 413                 return -ENOBUFS;
 414
 415         spin_lock_bh(&p->tcf_lock);
 416         memcpy(opt->keys, p->tcfp_keys,
 417                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 418         opt->index = p->tcf_index;
 419         opt->nkeys = p->tcfp_nkeys;
 420         opt->flags = p->tcfp_flags;
 421         opt->action = p->tcf_action;
 422         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 423         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 424
 425         if (p->tcfp_keys_ex) {
 426                 if (tcf_pedit_key_ex_dump(skb,
 427                                           p->tcfp_keys_ex,
 428                                           p->tcfp_nkeys))
 429                         goto nla_put_failure;
 430
 431                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 432                         goto nla_put_failure;
 433         } else {
 434                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 435                         goto nla_put_failure;
 436         }
 437
 438         tcf_tm_dump(&t, &p->tcf_tm);
 439         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 440                 goto nla_put_failure;
 441         spin_unlock_bh(&p->tcf_lock);
 442
 443         kfree(opt);
 444         return skb->len;
 445
 446 nla_put_failure:
 447         spin_unlock_bh(&p->tcf_lock);
 448         nlmsg_trim(skb, b);
 449         kfree(opt);
 450         return -1;
 451 }
 452
 453 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 454                             struct netlink_callback *cb, int type,
 455                             const struct tc_action_ops *ops,
 456                             struct netlink_ext_ack *extack)
 457 {
 458         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 459
 460         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 461 }
 462
 463 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 464 {
 465         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 466
 467         return tcf_idr_search(tn, a, index);
 468 }
 469
 470 static struct tc_action_ops act_pedit_ops = {
 471         .kind           =       "pedit",
 472         .type           =       TCA_ACT_PEDIT,
 473         .owner          =       THIS_MODULE,
 474         .act            =       tcf_pedit_act,
 475         .dump           =       tcf_pedit_dump,
 476         .cleanup        =       tcf_pedit_cleanup,
 477         .init           =       tcf_pedit_init,
 478         .walk           =       tcf_pedit_walker,
 479         .lookup         =       tcf_pedit_search,
 480         .size           =       sizeof(struct tcf_pedit),
 481 };
 482
 483 static __net_init int pedit_init_net(struct net *net)
 484 {
 485         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 486
 487         return tc_action_net_init(tn, &act_pedit_ops);
 488 }
 489
 490 static void __net_exit pedit_exit_net(struct list_head *net_list)
 491 {
 492         tc_action_net_exit(net_list, pedit_net_id);
 493 }
 494
 495 static struct pernet_operations pedit_net_ops = {
 496         .init = pedit_init_net,
 497         .exit_batch = pedit_exit_net,
 498         .id   = &pedit_net_id,
 499         .size = sizeof(struct tc_action_net),
 500 };
 501
 502 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 503 MODULE_DESCRIPTION("Generic Packet Editor actions");
 504 MODULE_LICENSE("GPL");
 505
 506 static int __init pedit_init_module(void)
 507 {
 508         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 509 }
 510
 511 static void __exit pedit_cleanup_module(void)
 512 {
 513         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 514 }
 515
 516 module_init(pedit_init_module);
 517 module_exit(pedit_cleanup_module);