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