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