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_PARMS_EX]    = { .len = sizeof(struct tc_pedit) },
  33         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  34 };
  35
  36 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  37         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  38         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  39 };
  40
  41 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  42                                                         u8 n)
  43 {
  44         struct tcf_pedit_key_ex *keys_ex;
  45         struct tcf_pedit_key_ex *k;
  46         const struct nlattr *ka;
  47         int err = -EINVAL;
  48         int rem;
  49
  50         if (!nla)
  51                 return NULL;
  52
  53         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  54         if (!keys_ex)
  55                 return ERR_PTR(-ENOMEM);
  56
  57         k = keys_ex;
  58
  59         nla_for_each_nested(ka, nla, rem) {
  60                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  61
  62                 if (!n) {
  63                         err = -EINVAL;
  64                         goto err_out;
  65                 }
  66                 n--;
  67
  68                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  69                         err = -EINVAL;
  70                         goto err_out;
  71                 }
  72
  73                 err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
  74                                        pedit_key_ex_policy, NULL);
  75                 if (err)
  76                         goto err_out;
  77
  78                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  79                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  80                         err = -EINVAL;
  81                         goto err_out;
  82                 }
  83
  84                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  85                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  86
  87                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  88                     k->cmd > TCA_PEDIT_CMD_MAX) {
  89                         err = -EINVAL;
  90                         goto err_out;
  91                 }
  92
  93                 k++;
  94         }
  95
  96         if (n) {
  97                 err = -EINVAL;
  98                 goto err_out;
  99         }
 100
 101         return keys_ex;
 102
 103 err_out:
 104         kfree(keys_ex);
 105         return ERR_PTR(err);
 106 }
 107
 108 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 109                                  struct tcf_pedit_key_ex *keys_ex, int n)
 110 {
 111         struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);
 112
 113         if (!keys_start)
 114                 goto nla_failure;
 115         for (; n > 0; n--) {
 116                 struct nlattr *key_start;
 117
 118                 key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
 119                 if (!key_start)
 120                         goto nla_failure;
 121
 122                 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 123                     nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
 124                         goto nla_failure;
 125
 126                 nla_nest_end(skb, key_start);
 127
 128                 keys_ex++;
 129         }
 130
 131         nla_nest_end(skb, keys_start);
 132
 133         return 0;
 134 nla_failure:
 135         nla_nest_cancel(skb, keys_start);
 136         return -EINVAL;
 137 }
 138
 139 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 140                           struct nlattr *est, struct tc_action **a,
 141                           int ovr, int bind)
 142 {
 143         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 144         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 145         struct nlattr *pattr;
 146         struct tc_pedit *parm;
 147         int ret = 0, err;
 148         struct tcf_pedit *p;
 149         struct tc_pedit_key *keys = NULL;
 150         struct tcf_pedit_key_ex *keys_ex;
 151         int ksize;
 152
 153         if (nla == NULL)
 154                 return -EINVAL;
 155
 156         err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
 157         if (err < 0)
 158                 return err;
 159
 160         pattr = tb[TCA_PEDIT_PARMS];
 161         if (!pattr)
 162                 pattr = tb[TCA_PEDIT_PARMS_EX];
 163         if (!pattr)
 164                 return -EINVAL;
 165
 166         parm = nla_data(pattr);
 167         if (!parm->nkeys)
 168                 return -EINVAL;
 169
 170         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 171         if (nla_len(pattr) < sizeof(*parm) + ksize)
 172                 return -EINVAL;
 173
 174         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 175         if (IS_ERR(keys_ex))
 176                 return PTR_ERR(keys_ex);
 177
 178         if (!tcf_idr_check(tn, parm->index, a, bind)) {
 179                 ret = tcf_idr_create(tn, parm->index, est, a,
 180                                      &act_pedit_ops, bind, false);
 181                 if (ret)
 182                         return ret;
 183                 p = to_pedit(*a);
 184                 keys = kmalloc(ksize, GFP_KERNEL);
 185                 if (keys == NULL) {
 186                         tcf_idr_release(*a, bind);
 187                         kfree(keys_ex);
 188                         return -ENOMEM;
 189                 }
 190                 ret = ACT_P_CREATED;
 191         } else {
 192                 if (bind)
 193                         return 0;
 194                 tcf_idr_release(*a, bind);
 195                 if (!ovr)
 196                         return -EEXIST;
 197                 p = to_pedit(*a);
 198                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
 199                         keys = kmalloc(ksize, GFP_KERNEL);
 200                         if (!keys) {
 201                                 kfree(keys_ex);
 202                                 return -ENOMEM;
 203                         }
 204                 }
 205         }
 206
 207         spin_lock_bh(&p->tcf_lock);
 208         p->tcfp_flags = parm->flags;
 209         p->tcf_action = parm->action;
 210         if (keys) {
 211                 kfree(p->tcfp_keys);
 212                 p->tcfp_keys = keys;
 213                 p->tcfp_nkeys = parm->nkeys;
 214         }
 215         memcpy(p->tcfp_keys, parm->keys, ksize);
 216
 217         kfree(p->tcfp_keys_ex);
 218         p->tcfp_keys_ex = keys_ex;
 219
 220         spin_unlock_bh(&p->tcf_lock);
 221         if (ret == ACT_P_CREATED)
 222                 tcf_idr_insert(tn, *a);
 223         return ret;
 224 }
 225
 226 static void tcf_pedit_cleanup(struct tc_action *a, int bind)
 227 {
 228         struct tcf_pedit *p = to_pedit(a);
 229         struct tc_pedit_key *keys = p->tcfp_keys;
 230         kfree(keys);
 231         kfree(p->tcfp_keys_ex);
 232 }
 233
 234 static bool offset_valid(struct sk_buff *skb, int offset)
 235 {
 236         if (offset > 0 && offset > skb->len)
 237                 return false;
 238
 239         if  (offset < 0 && -offset > skb_headroom(skb))
 240                 return false;
 241
 242         return true;
 243 }
 244
 245 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 246                                 enum pedit_header_type htype, int *hoffset)
 247 {
 248         int ret = -EINVAL;
 249
 250         switch (htype) {
 251         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 252                 if (skb_mac_header_was_set(skb)) {
 253                         *hoffset = skb_mac_offset(skb);
 254                         ret = 0;
 255                 }
 256                 break;
 257         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 258         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 259         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 260                 *hoffset = skb_network_offset(skb);
 261                 ret = 0;
 262                 break;
 263         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 264         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 265                 if (skb_transport_header_was_set(skb)) {
 266                         *hoffset = skb_transport_offset(skb);
 267                         ret = 0;
 268                 }
 269                 break;
 270         default:
 271                 ret = -EINVAL;
 272                 break;
 273         };
 274
 275         return ret;
 276 }
 277
 278 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 279                      struct tcf_result *res)
 280 {
 281         struct tcf_pedit *p = to_pedit(a);
 282         int i;
 283
 284         if (skb_unclone(skb, GFP_ATOMIC))
 285                 return p->tcf_action;
 286
 287         spin_lock(&p->tcf_lock);
 288
 289         tcf_lastuse_update(&p->tcf_tm);
 290
 291         if (p->tcfp_nkeys > 0) {
 292                 struct tc_pedit_key *tkey = p->tcfp_keys;
 293                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 294                 enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 295                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 296
 297                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 298                         u32 *ptr, _data;
 299                         int offset = tkey->off;
 300                         int hoffset;
 301                         u32 val;
 302                         int rc;
 303
 304                         if (tkey_ex) {
 305                                 htype = tkey_ex->htype;
 306                                 cmd = tkey_ex->cmd;
 307
 308                                 tkey_ex++;
 309                         }
 310
 311                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 312                         if (rc) {
 313                                 pr_info("tc filter pedit bad header type specified (0x%x)\n",
 314                                         htype);
 315                                 goto bad;
 316                         }
 317
 318                         if (tkey->offmask) {
 319                                 char *d, _d;
 320
 321                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 322                                         pr_info("tc filter pedit 'at' offset %d out of bounds\n",
 323                                                 hoffset + tkey->at);
 324                                         goto bad;
 325                                 }
 326                                 d = skb_header_pointer(skb, hoffset + tkey->at, 1,
 327                                                        &_d);
 328                                 if (!d)
 329                                         goto bad;
 330                                 offset += (*d & tkey->offmask) >> tkey->shift;
 331                         }
 332
 333                         if (offset % 4) {
 334                                 pr_info("tc filter pedit"
 335                                         " offset must be on 32 bit boundaries\n");
 336                                 goto bad;
 337                         }
 338
 339                         if (!offset_valid(skb, hoffset + offset)) {
 340                                 pr_info("tc filter pedit offset %d out of bounds\n",
 341                                         hoffset + offset);
 342                                 goto bad;
 343                         }
 344
 345                         ptr = skb_header_pointer(skb, hoffset + offset, 4, &_data);
 346                         if (!ptr)
 347                                 goto bad;
 348                         /* just do it, baby */
 349                         switch (cmd) {
 350                         case TCA_PEDIT_KEY_EX_CMD_SET:
 351                                 val = tkey->val;
 352                                 break;
 353                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 354                                 val = (*ptr + tkey->val) & ~tkey->mask;
 355                                 break;
 356                         default:
 357                                 pr_info("tc filter pedit bad command (%d)\n",
 358                                         cmd);
 359                                 goto bad;
 360                         }
 361
 362                         *ptr = ((*ptr & tkey->mask) ^ val);
 363                         if (ptr == &_data)
 364                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 365                 }
 366
 367                 goto done;
 368         } else
 369                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 370
 371 bad:
 372         p->tcf_qstats.overlimits++;
 373 done:
 374         bstats_update(&p->tcf_bstats, skb);
 375         spin_unlock(&p->tcf_lock);
 376         return p->tcf_action;
 377 }
 378
 379 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 380                           int bind, int ref)
 381 {
 382         unsigned char *b = skb_tail_pointer(skb);
 383         struct tcf_pedit *p = to_pedit(a);
 384         struct tc_pedit *opt;
 385         struct tcf_t t;
 386         int s;
 387
 388         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 389
 390         /* netlink spinlocks held above us - must use ATOMIC */
 391         opt = kzalloc(s, GFP_ATOMIC);
 392         if (unlikely(!opt))
 393                 return -ENOBUFS;
 394
 395         memcpy(opt->keys, p->tcfp_keys,
 396                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 397         opt->index = p->tcf_index;
 398         opt->nkeys = p->tcfp_nkeys;
 399         opt->flags = p->tcfp_flags;
 400         opt->action = p->tcf_action;
 401         opt->refcnt = p->tcf_refcnt - ref;
 402         opt->bindcnt = p->tcf_bindcnt - bind;
 403
 404         if (p->tcfp_keys_ex) {
 405                 if (tcf_pedit_key_ex_dump(skb,
 406                                           p->tcfp_keys_ex,
 407                                           p->tcfp_nkeys))
 408                         goto nla_put_failure;
 409
 410                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 411                         goto nla_put_failure;
 412         } else {
 413                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 414                         goto nla_put_failure;
 415         }
 416
 417         tcf_tm_dump(&t, &p->tcf_tm);
 418         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 419                 goto nla_put_failure;
 420
 421         kfree(opt);
 422         return skb->len;
 423
 424 nla_put_failure:
 425         nlmsg_trim(skb, b);
 426         kfree(opt);
 427         return -1;
 428 }
 429
 430 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 431                             struct netlink_callback *cb, int type,
 432                             const struct tc_action_ops *ops)
 433 {
 434         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 435
 436         return tcf_generic_walker(tn, skb, cb, type, ops);
 437 }
 438
 439 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 440 {
 441         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 442
 443         return tcf_idr_search(tn, a, index);
 444 }
 445
 446 static struct tc_action_ops act_pedit_ops = {
 447         .kind           =       "pedit",
 448         .type           =       TCA_ACT_PEDIT,
 449         .owner          =       THIS_MODULE,
 450         .act            =       tcf_pedit,
 451         .dump           =       tcf_pedit_dump,
 452         .cleanup        =       tcf_pedit_cleanup,
 453         .init           =       tcf_pedit_init,
 454         .walk           =       tcf_pedit_walker,
 455         .lookup         =       tcf_pedit_search,
 456         .size           =       sizeof(struct tcf_pedit),
 457 };
 458
 459 static __net_init int pedit_init_net(struct net *net)
 460 {
 461         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 462
 463         return tc_action_net_init(net, tn, &act_pedit_ops);
 464 }
 465
 466 static void __net_exit pedit_exit_net(struct net *net)
 467 {
 468         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 469
 470         tc_action_net_exit(tn);
 471 }
 472
 473 static struct pernet_operations pedit_net_ops = {
 474         .init = pedit_init_net,
 475         .exit = pedit_exit_net,
 476         .id   = &pedit_net_id,
 477         .size = sizeof(struct tc_action_net),
 478 };
 479
 480 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 481 MODULE_DESCRIPTION("Generic Packet Editor actions");
 482 MODULE_LICENSE("GPL");
 483
 484 static int __init pedit_init_module(void)
 485 {
 486         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 487 }
 488
 489 static void __exit pedit_cleanup_module(void)
 490 {
 491         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 492 }
 493
 494 module_init(pedit_init_module);
 495 module_exit(pedit_cleanup_module);
 496