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 #define PEDIT_TAB_MASK  15
  28
  29 static unsigned int pedit_net_id;
  30 static struct tc_action_ops act_pedit_ops;
  31
  32 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  33         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  34         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  35 };
  36
  37 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  38         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  39         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  40 };
  41
  42 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  43                                                         u8 n)
  44 {
  45         struct tcf_pedit_key_ex *keys_ex;
  46         struct tcf_pedit_key_ex *k;
  47         const struct nlattr *ka;
  48         int err = -EINVAL;
  49         int rem;
  50
  51         if (!nla || !n)
  52                 return NULL;
  53
  54         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  55         if (!keys_ex)
  56                 return ERR_PTR(-ENOMEM);
  57
  58         k = keys_ex;
  59
  60         nla_for_each_nested(ka, nla, rem) {
  61                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  62
  63                 if (!n) {
  64                         err = -EINVAL;
  65                         goto err_out;
  66                 }
  67                 n--;
  68
  69                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  70                         err = -EINVAL;
  71                         goto err_out;
  72                 }
  73
  74                 err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
  75                                        pedit_key_ex_policy, NULL);
  76                 if (err)
  77                         goto err_out;
  78
  79                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  80                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  81                         err = -EINVAL;
  82                         goto err_out;
  83                 }
  84
  85                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  86                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  87
  88                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  89                     k->cmd > TCA_PEDIT_CMD_MAX) {
  90                         err = -EINVAL;
  91                         goto err_out;
  92                 }
  93
  94                 k++;
  95         }
  96
  97         if (n) {
  98                 err = -EINVAL;
  99                 goto err_out;
 100         }
 101
 102         return keys_ex;
 103
 104 err_out:
 105         kfree(keys_ex);
 106         return ERR_PTR(err);
 107 }
 108
 109 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 110                                  struct tcf_pedit_key_ex *keys_ex, int n)
 111 {
 112         struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);
 113
 114         for (; n > 0; n--) {
 115                 struct nlattr *key_start;
 116
 117                 key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
 118
 119                 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 120                     nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd)) {
 121                         nlmsg_trim(skb, keys_start);
 122                         return -EINVAL;
 123                 }
 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 }
 134
 135 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 136                           struct nlattr *est, struct tc_action **a,
 137                           int ovr, int bind)
 138 {
 139         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 140         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 141         struct nlattr *pattr;
 142         struct tc_pedit *parm;
 143         int ret = 0, err;
 144         struct tcf_pedit *p;
 145         struct tc_pedit_key *keys = NULL;
 146         struct tcf_pedit_key_ex *keys_ex;
 147         int ksize;
 148
 149         if (nla == NULL)
 150                 return -EINVAL;
 151
 152         err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
 153         if (err < 0)
 154                 return err;
 155
 156         pattr = tb[TCA_PEDIT_PARMS];
 157         if (!pattr)
 158                 pattr = tb[TCA_PEDIT_PARMS_EX];
 159         if (!pattr)
 160                 return -EINVAL;
 161
 162         parm = nla_data(pattr);
 163         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 164         if (nla_len(pattr) < sizeof(*parm) + ksize)
 165                 return -EINVAL;
 166
 167         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 168         if (IS_ERR(keys_ex))
 169                 return PTR_ERR(keys_ex);
 170
 171         if (!tcf_hash_check(tn, parm->index, a, bind)) {
 172                 if (!parm->nkeys)
 173                         return -EINVAL;
 174                 ret = tcf_hash_create(tn, parm->index, est, a,
 175                                       &act_pedit_ops, bind, false);
 176                 if (ret)
 177                         return ret;
 178                 p = to_pedit(*a);
 179                 keys = kmalloc(ksize, GFP_KERNEL);
 180                 if (keys == NULL) {
 181                         tcf_hash_cleanup(*a, est);
 182                         kfree(keys_ex);
 183                         return -ENOMEM;
 184                 }
 185                 ret = ACT_P_CREATED;
 186         } else {
 187                 if (bind)
 188                         return 0;
 189                 tcf_hash_release(*a, bind);
 190                 if (!ovr)
 191                         return -EEXIST;
 192                 p = to_pedit(*a);
 193                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
 194                         keys = kmalloc(ksize, GFP_KERNEL);
 195                         if (!keys) {
 196                                 kfree(keys_ex);
 197                                 return -ENOMEM;
 198                         }
 199                 }
 200         }
 201
 202         spin_lock_bh(&p->tcf_lock);
 203         p->tcfp_flags = parm->flags;
 204         p->tcf_action = parm->action;
 205         if (keys) {
 206                 kfree(p->tcfp_keys);
 207                 p->tcfp_keys = keys;
 208                 p->tcfp_nkeys = parm->nkeys;
 209         }
 210         memcpy(p->tcfp_keys, parm->keys, ksize);
 211
 212         kfree(p->tcfp_keys_ex);
 213         p->tcfp_keys_ex = keys_ex;
 214
 215         spin_unlock_bh(&p->tcf_lock);
 216         if (ret == ACT_P_CREATED)
 217                 tcf_hash_insert(tn, *a);
 218         return ret;
 219 }
 220
 221 static void tcf_pedit_cleanup(struct tc_action *a, int bind)
 222 {
 223         struct tcf_pedit *p = to_pedit(a);
 224         struct tc_pedit_key *keys = p->tcfp_keys;
 225         kfree(keys);
 226         kfree(p->tcfp_keys_ex);
 227 }
 228
 229 static bool offset_valid(struct sk_buff *skb, int offset)
 230 {
 231         if (offset > 0 && offset > skb->len)
 232                 return false;
 233
 234         if  (offset < 0 && -offset > skb_headroom(skb))
 235                 return false;
 236
 237         return true;
 238 }
 239
 240 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 241                                 enum pedit_header_type htype, int *hoffset)
 242 {
 243         int ret = -EINVAL;
 244
 245         switch (htype) {
 246         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 247                 if (skb_mac_header_was_set(skb)) {
 248                         *hoffset = skb_mac_offset(skb);
 249                         ret = 0;
 250                 }
 251                 break;
 252         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 253         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 254         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 255                 *hoffset = skb_network_offset(skb);
 256                 ret = 0;
 257                 break;
 258         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 259         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 260                 if (skb_transport_header_was_set(skb)) {
 261                         *hoffset = skb_transport_offset(skb);
 262                         ret = 0;
 263                 }
 264                 break;
 265         default:
 266                 ret = -EINVAL;
 267                 break;
 268         };
 269
 270         return ret;
 271 }
 272
 273 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 274                      struct tcf_result *res)
 275 {
 276         struct tcf_pedit *p = to_pedit(a);
 277         int i;
 278
 279         if (skb_unclone(skb, GFP_ATOMIC))
 280                 return p->tcf_action;
 281
 282         spin_lock(&p->tcf_lock);
 283
 284         tcf_lastuse_update(&p->tcf_tm);
 285
 286         if (p->tcfp_nkeys > 0) {
 287                 struct tc_pedit_key *tkey = p->tcfp_keys;
 288                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 289                 enum pedit_header_type htype = 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, _data;
 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, 1,
 322                                                        &_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"
 330                                         " offset must be on 32 bit boundaries\n");
 331                                 goto bad;
 332                         }
 333
 334                         if (!offset_valid(skb, hoffset + offset)) {
 335                                 pr_info("tc filter pedit offset %d out of bounds\n",
 336                                         hoffset + offset);
 337                                 goto bad;
 338                         }
 339
 340                         ptr = skb_header_pointer(skb, hoffset + offset, 4, &_data);
 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 == &_data)
 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 bad:
 367         p->tcf_qstats.overlimits++;
 368 done:
 369         bstats_update(&p->tcf_bstats, skb);
 370         spin_unlock(&p->tcf_lock);
 371         return p->tcf_action;
 372 }
 373
 374 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 375                           int bind, int ref)
 376 {
 377         unsigned char *b = skb_tail_pointer(skb);
 378         struct tcf_pedit *p = to_pedit(a);
 379         struct tc_pedit *opt;
 380         struct tcf_t t;
 381         int s;
 382
 383         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 384
 385         /* netlink spinlocks held above us - must use ATOMIC */
 386         opt = kzalloc(s, GFP_ATOMIC);
 387         if (unlikely(!opt))
 388                 return -ENOBUFS;
 389
 390         memcpy(opt->keys, p->tcfp_keys,
 391                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 392         opt->index = p->tcf_index;
 393         opt->nkeys = p->tcfp_nkeys;
 394         opt->flags = p->tcfp_flags;
 395         opt->action = p->tcf_action;
 396         opt->refcnt = p->tcf_refcnt - ref;
 397         opt->bindcnt = p->tcf_bindcnt - bind;
 398
 399         if (p->tcfp_keys_ex) {
 400                 tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
 401
 402                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 403                         goto nla_put_failure;
 404         } else {
 405                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 406                         goto nla_put_failure;
 407         }
 408
 409         tcf_tm_dump(&t, &p->tcf_tm);
 410         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 411                 goto nla_put_failure;
 412
 413         kfree(opt);
 414         return skb->len;
 415
 416 nla_put_failure:
 417         nlmsg_trim(skb, b);
 418         kfree(opt);
 419         return -1;
 420 }
 421
 422 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 423                             struct netlink_callback *cb, int type,
 424                             const struct tc_action_ops *ops)
 425 {
 426         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 427
 428         return tcf_generic_walker(tn, skb, cb, type, ops);
 429 }
 430
 431 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 432 {
 433         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 434
 435         return tcf_hash_search(tn, a, index);
 436 }
 437
 438 static struct tc_action_ops act_pedit_ops = {
 439         .kind           =       "pedit",
 440         .type           =       TCA_ACT_PEDIT,
 441         .owner          =       THIS_MODULE,
 442         .act            =       tcf_pedit,
 443         .dump           =       tcf_pedit_dump,
 444         .cleanup        =       tcf_pedit_cleanup,
 445         .init           =       tcf_pedit_init,
 446         .walk           =       tcf_pedit_walker,
 447         .lookup         =       tcf_pedit_search,
 448         .size           =       sizeof(struct tcf_pedit),
 449 };
 450
 451 static __net_init int pedit_init_net(struct net *net)
 452 {
 453         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 454
 455         return tc_action_net_init(tn, &act_pedit_ops, PEDIT_TAB_MASK);
 456 }
 457
 458 static void __net_exit pedit_exit_net(struct net *net)
 459 {
 460         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 461
 462         tc_action_net_exit(tn);
 463 }
 464
 465 static struct pernet_operations pedit_net_ops = {
 466         .init = pedit_init_net,
 467         .exit = pedit_exit_net,
 468         .id   = &pedit_net_id,
 469         .size = sizeof(struct tc_action_net),
 470 };
 471
 472 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 473 MODULE_DESCRIPTION("Generic Packet Editor actions");
 474 MODULE_LICENSE("GPL");
 475
 476 static int __init pedit_init_module(void)
 477 {
 478         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 479 }
 480
 481 static void __exit pedit_cleanup_module(void)
 482 {
 483         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 484 }
 485
 486 module_init(pedit_init_module);
 487 module_exit(pedit_cleanup_module);
 488