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