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, bool rtnl_held,
 136                           struct netlink_ext_ack *extack)
 137 {
 138         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 139         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 140         struct tc_pedit_key *keys = NULL;
 141         struct tcf_pedit_key_ex *keys_ex;
 142         struct tc_pedit *parm;
 143         struct nlattr *pattr;
 144         struct tcf_pedit *p;
 145         int ret = 0, err;
 146         int ksize;
 147
 148         if (!nla) {
 149                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 150                 return -EINVAL;
 151         }
 152
 153         err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
 154         if (err < 0)
 155                 return err;
 156
 157         pattr = tb[TCA_PEDIT_PARMS];
 158         if (!pattr)
 159                 pattr = tb[TCA_PEDIT_PARMS_EX];
 160         if (!pattr) {
 161                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 162                 return -EINVAL;
 163         }
 164
 165         parm = nla_data(pattr);
 166         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 167         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 168                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 169                 return -EINVAL;
 170         }
 171
 172         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 173         if (IS_ERR(keys_ex))
 174                 return PTR_ERR(keys_ex);
 175
 176         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 177         if (!err) {
 178                 if (!parm->nkeys) {
 179                         tcf_idr_cleanup(tn, parm->index);
 180                         NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 181                         ret = -EINVAL;
 182                         goto out_free;
 183                 }
 184                 ret = tcf_idr_create(tn, parm->index, est, a,
 185                                      &act_pedit_ops, bind, false);
 186                 if (ret) {
 187                         tcf_idr_cleanup(tn, parm->index);
 188                         goto out_free;
 189                 }
 190                 ret = ACT_P_CREATED;
 191         } else if (err > 0) {
 192                 if (bind)
 193                         goto out_free;
 194                 if (!ovr) {
 195                         ret = -EEXIST;
 196                         goto out_release;
 197                 }
 198         } else {
 199                 return err;
 200         }
 201
 202         p = to_pedit(*a);
 203         spin_lock_bh(&p->tcf_lock);
 204
 205         if (ret == ACT_P_CREATED ||
 206             (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 207                 keys = kmalloc(ksize, GFP_ATOMIC);
 208                 if (!keys) {
 209                         spin_unlock_bh(&p->tcf_lock);
 210                         ret = -ENOMEM;
 211                         goto out_release;
 212                 }
 213                 kfree(p->tcfp_keys);
 214                 p->tcfp_keys = keys;
 215                 p->tcfp_nkeys = parm->nkeys;
 216         }
 217         memcpy(p->tcfp_keys, parm->keys, ksize);
 218
 219         p->tcfp_flags = parm->flags;
 220         p->tcf_action = parm->action;
 221
 222         kfree(p->tcfp_keys_ex);
 223         p->tcfp_keys_ex = keys_ex;
 224
 225         spin_unlock_bh(&p->tcf_lock);
 226         if (ret == ACT_P_CREATED)
 227                 tcf_idr_insert(tn, *a);
 228         return ret;
 229
 230 out_release:
 231         tcf_idr_release(*a, bind);
 232 out_free:
 233         kfree(keys_ex);
 234         return ret;
 235
 236 }
 237
 238 static void tcf_pedit_cleanup(struct tc_action *a)
 239 {
 240         struct tcf_pedit *p = to_pedit(a);
 241         struct tc_pedit_key *keys = p->tcfp_keys;
 242
 243         kfree(keys);
 244         kfree(p->tcfp_keys_ex);
 245 }
 246
 247 static bool offset_valid(struct sk_buff *skb, int offset)
 248 {
 249         if (offset > 0 && offset > skb->len)
 250                 return false;
 251
 252         if  (offset < 0 && -offset > skb_headroom(skb))
 253                 return false;
 254
 255         return true;
 256 }
 257
 258 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 259                                 enum pedit_header_type htype, int *hoffset)
 260 {
 261         int ret = -EINVAL;
 262
 263         switch (htype) {
 264         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 265                 if (skb_mac_header_was_set(skb)) {
 266                         *hoffset = skb_mac_offset(skb);
 267                         ret = 0;
 268                 }
 269                 break;
 270         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 271         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 272         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 273                 *hoffset = skb_network_offset(skb);
 274                 ret = 0;
 275                 break;
 276         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 277         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 278                 if (skb_transport_header_was_set(skb)) {
 279                         *hoffset = skb_transport_offset(skb);
 280                         ret = 0;
 281                 }
 282                 break;
 283         default:
 284                 ret = -EINVAL;
 285                 break;
 286         }
 287
 288         return ret;
 289 }
 290
 291 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 292                          struct tcf_result *res)
 293 {
 294         struct tcf_pedit *p = to_pedit(a);
 295         int i;
 296
 297         if (skb_unclone(skb, GFP_ATOMIC))
 298                 return p->tcf_action;
 299
 300         spin_lock(&p->tcf_lock);
 301
 302         tcf_lastuse_update(&p->tcf_tm);
 303
 304         if (p->tcfp_nkeys > 0) {
 305                 struct tc_pedit_key *tkey = p->tcfp_keys;
 306                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 307                 enum pedit_header_type htype =
 308                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 309                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 310
 311                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 312                         u32 *ptr, hdata;
 313                         int offset = tkey->off;
 314                         int hoffset;
 315                         u32 val;
 316                         int rc;
 317
 318                         if (tkey_ex) {
 319                                 htype = tkey_ex->htype;
 320                                 cmd = tkey_ex->cmd;
 321
 322                                 tkey_ex++;
 323                         }
 324
 325                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 326                         if (rc) {
 327                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 328                                         htype);
 329                                 goto bad;
 330                         }
 331
 332                         if (tkey->offmask) {
 333                                 u8 *d, _d;
 334
 335                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 336                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 337                                                 hoffset + tkey->at);
 338                                         goto bad;
 339                                 }
 340                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 341                                                        sizeof(_d), &_d);
 342                                 if (!d)
 343                                         goto bad;
 344                                 offset += (*d & tkey->offmask) >> tkey->shift;
 345                         }
 346
 347                         if (offset % 4) {
 348                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 349                                 goto bad;
 350                         }
 351
 352                         if (!offset_valid(skb, hoffset + offset)) {
 353                                 pr_info("tc action pedit offset %d out of bounds\n",
 354                                         hoffset + offset);
 355                                 goto bad;
 356                         }
 357
 358                         ptr = skb_header_pointer(skb, hoffset + offset,
 359                                                  sizeof(hdata), &hdata);
 360                         if (!ptr)
 361                                 goto bad;
 362                         /* just do it, baby */
 363                         switch (cmd) {
 364                         case TCA_PEDIT_KEY_EX_CMD_SET:
 365                                 val = tkey->val;
 366                                 break;
 367                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 368                                 val = (*ptr + tkey->val) & ~tkey->mask;
 369                                 break;
 370                         default:
 371                                 pr_info("tc action pedit bad command (%d)\n",
 372                                         cmd);
 373                                 goto bad;
 374                         }
 375
 376                         *ptr = ((*ptr & tkey->mask) ^ val);
 377                         if (ptr == &hdata)
 378                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 379                 }
 380
 381                 goto done;
 382         } else {
 383                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 384         }
 385
 386 bad:
 387         p->tcf_qstats.overlimits++;
 388 done:
 389         bstats_update(&p->tcf_bstats, skb);
 390         spin_unlock(&p->tcf_lock);
 391         return p->tcf_action;
 392 }
 393
 394 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 395                           int bind, int ref)
 396 {
 397         unsigned char *b = skb_tail_pointer(skb);
 398         struct tcf_pedit *p = to_pedit(a);
 399         struct tc_pedit *opt;
 400         struct tcf_t t;
 401         int s;
 402
 403         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 404
 405         /* netlink spinlocks held above us - must use ATOMIC */
 406         opt = kzalloc(s, GFP_ATOMIC);
 407         if (unlikely(!opt))
 408                 return -ENOBUFS;
 409
 410         spin_lock_bh(&p->tcf_lock);
 411         memcpy(opt->keys, p->tcfp_keys,
 412                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 413         opt->index = p->tcf_index;
 414         opt->nkeys = p->tcfp_nkeys;
 415         opt->flags = p->tcfp_flags;
 416         opt->action = p->tcf_action;
 417         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 418         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 419
 420         if (p->tcfp_keys_ex) {
 421                 tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
 422
 423                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 424                         goto nla_put_failure;
 425         } else {
 426                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 427                         goto nla_put_failure;
 428         }
 429
 430         tcf_tm_dump(&t, &p->tcf_tm);
 431         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 432                 goto nla_put_failure;
 433         spin_unlock_bh(&p->tcf_lock);
 434
 435         kfree(opt);
 436         return skb->len;
 437
 438 nla_put_failure:
 439         spin_unlock_bh(&p->tcf_lock);
 440         nlmsg_trim(skb, b);
 441         kfree(opt);
 442         return -1;
 443 }
 444
 445 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 446                             struct netlink_callback *cb, int type,
 447                             const struct tc_action_ops *ops,
 448                             struct netlink_ext_ack *extack)
 449 {
 450         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 451
 452         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 453 }
 454
 455 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index,
 456                             struct netlink_ext_ack *extack)
 457 {
 458         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 459
 460         return tcf_idr_search(tn, a, index);
 461 }
 462
 463 static struct tc_action_ops act_pedit_ops = {
 464         .kind           =       "pedit",
 465         .type           =       TCA_ACT_PEDIT,
 466         .owner          =       THIS_MODULE,
 467         .act            =       tcf_pedit_act,
 468         .dump           =       tcf_pedit_dump,
 469         .cleanup        =       tcf_pedit_cleanup,
 470         .init           =       tcf_pedit_init,
 471         .walk           =       tcf_pedit_walker,
 472         .lookup         =       tcf_pedit_search,
 473         .size           =       sizeof(struct tcf_pedit),
 474 };
 475
 476 static __net_init int pedit_init_net(struct net *net)
 477 {
 478         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 479
 480         return tc_action_net_init(tn, &act_pedit_ops);
 481 }
 482
 483 static void __net_exit pedit_exit_net(struct list_head *net_list)
 484 {
 485         tc_action_net_exit(net_list, pedit_net_id);
 486 }
 487
 488 static struct pernet_operations pedit_net_ops = {
 489         .init = pedit_init_net,
 490         .exit_batch = pedit_exit_net,
 491         .id   = &pedit_net_id,
 492         .size = sizeof(struct tc_action_net),
 493 };
 494
 495 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 496 MODULE_DESCRIPTION("Generic Packet Editor actions");
 497 MODULE_LICENSE("GPL");
 498
 499 static int __init pedit_init_module(void)
 500 {
 501         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 502 }
 503
 504 static void __exit pedit_cleanup_module(void)
 505 {
 506         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 507 }
 508
 509 module_init(pedit_init_module);
 510 module_exit(pedit_cleanup_module);