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 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, bool rtnl_held, 141 struct netlink_ext_ack *extack) 142 { 143 struct tc_action_net *tn = net_generic(net, pedit_net_id); 144 struct nlattr *tb[TCA_PEDIT_MAX + 1]; 145 struct tc_pedit_key *keys = NULL; 146 struct tcf_pedit_key_ex *keys_ex; 147 struct tc_pedit *parm; 148 struct nlattr *pattr; 149 struct tcf_pedit *p; 150 int ret = 0, err; 151 int ksize; 152 153 if (!nla) { 154 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed"); 155 return -EINVAL; 156 } 157 158 err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL); 159 if (err < 0) 160 return err; 161 162 pattr = tb[TCA_PEDIT_PARMS]; 163 if (!pattr) 164 pattr = tb[TCA_PEDIT_PARMS_EX]; 165 if (!pattr) { 166 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute"); 167 return -EINVAL; 168 } 169 170 parm = nla_data(pattr); 171 ksize = parm->nkeys * sizeof(struct tc_pedit_key); 172 if (nla_len(pattr) < sizeof(*parm) + ksize) { 173 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid"); 174 return -EINVAL; 175 } 176 177 keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys); 178 if (IS_ERR(keys_ex)) 179 return PTR_ERR(keys_ex); 180 181 err = tcf_idr_check_alloc(tn, &parm->index, a, bind); 182 if (!err) { 183 if (!parm->nkeys) { 184 tcf_idr_cleanup(tn, parm->index); 185 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed"); 186 ret = -EINVAL; 187 goto out_free; 188 } 189 ret = tcf_idr_create(tn, parm->index, est, a, 190 &act_pedit_ops, bind, false); 191 if (ret) { 192 tcf_idr_cleanup(tn, parm->index); 193 goto out_free; 194 } 195 ret = ACT_P_CREATED; 196 } else if (err > 0) { 197 if (bind) 198 goto out_free; 199 if (!ovr) { 200 ret = -EEXIST; 201 goto out_release; 202 } 203 } else { 204 return err; 205 } 206 207 p = to_pedit(*a); 208 spin_lock_bh(&p->tcf_lock); 209 210 if (ret == ACT_P_CREATED || 211 (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) { 212 keys = kmalloc(ksize, GFP_ATOMIC); 213 if (!keys) { 214 spin_unlock_bh(&p->tcf_lock); 215 ret = -ENOMEM; 216 goto out_release; 217 } 218 kfree(p->tcfp_keys); 219 p->tcfp_keys = keys; 220 p->tcfp_nkeys = parm->nkeys; 221 } 222 memcpy(p->tcfp_keys, parm->keys, ksize); 223 224 p->tcfp_flags = parm->flags; 225 p->tcf_action = parm->action; 226 227 kfree(p->tcfp_keys_ex); 228 p->tcfp_keys_ex = keys_ex; 229 230 spin_unlock_bh(&p->tcf_lock); 231 if (ret == ACT_P_CREATED) 232 tcf_idr_insert(tn, *a); 233 return ret; 234 235 out_release: 236 tcf_idr_release(*a, bind); 237 out_free: 238 kfree(keys_ex); 239 return ret; 240 241 } 242 243 static void tcf_pedit_cleanup(struct tc_action *a) 244 { 245 struct tcf_pedit *p = to_pedit(a); 246 struct tc_pedit_key *keys = p->tcfp_keys; 247 248 kfree(keys); 249 kfree(p->tcfp_keys_ex); 250 } 251 252 static bool offset_valid(struct sk_buff *skb, int offset) 253 { 254 if (offset > 0 && offset > skb->len) 255 return false; 256 257 if (offset < 0 && -offset > skb_headroom(skb)) 258 return false; 259 260 return true; 261 } 262 263 static int pedit_skb_hdr_offset(struct sk_buff *skb, 264 enum pedit_header_type htype, int *hoffset) 265 { 266 int ret = -EINVAL; 267 268 switch (htype) { 269 case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH: 270 if (skb_mac_header_was_set(skb)) { 271 *hoffset = skb_mac_offset(skb); 272 ret = 0; 273 } 274 break; 275 case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK: 276 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4: 277 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6: 278 *hoffset = skb_network_offset(skb); 279 ret = 0; 280 break; 281 case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP: 282 case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP: 283 if (skb_transport_header_was_set(skb)) { 284 *hoffset = skb_transport_offset(skb); 285 ret = 0; 286 } 287 break; 288 default: 289 ret = -EINVAL; 290 break; 291 } 292 293 return ret; 294 } 295 296 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a, 297 struct tcf_result *res) 298 { 299 struct tcf_pedit *p = to_pedit(a); 300 int i; 301 302 if (skb_unclone(skb, GFP_ATOMIC)) 303 return p->tcf_action; 304 305 spin_lock(&p->tcf_lock); 306 307 tcf_lastuse_update(&p->tcf_tm); 308 309 if (p->tcfp_nkeys > 0) { 310 struct tc_pedit_key *tkey = p->tcfp_keys; 311 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex; 312 enum pedit_header_type htype = 313 TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK; 314 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET; 315 316 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 317 u32 *ptr, hdata; 318 int offset = tkey->off; 319 int hoffset; 320 u32 val; 321 int rc; 322 323 if (tkey_ex) { 324 htype = tkey_ex->htype; 325 cmd = tkey_ex->cmd; 326 327 tkey_ex++; 328 } 329 330 rc = pedit_skb_hdr_offset(skb, htype, &hoffset); 331 if (rc) { 332 pr_info("tc action pedit bad header type specified (0x%x)\n", 333 htype); 334 goto bad; 335 } 336 337 if (tkey->offmask) { 338 u8 *d, _d; 339 340 if (!offset_valid(skb, hoffset + tkey->at)) { 341 pr_info("tc action pedit 'at' offset %d out of bounds\n", 342 hoffset + tkey->at); 343 goto bad; 344 } 345 d = skb_header_pointer(skb, hoffset + tkey->at, 346 sizeof(_d), &_d); 347 if (!d) 348 goto bad; 349 offset += (*d & tkey->offmask) >> tkey->shift; 350 } 351 352 if (offset % 4) { 353 pr_info("tc action pedit offset must be on 32 bit boundaries\n"); 354 goto bad; 355 } 356 357 if (!offset_valid(skb, hoffset + offset)) { 358 pr_info("tc action pedit offset %d out of bounds\n", 359 hoffset + offset); 360 goto bad; 361 } 362 363 ptr = skb_header_pointer(skb, hoffset + offset, 364 sizeof(hdata), &hdata); 365 if (!ptr) 366 goto bad; 367 /* just do it, baby */ 368 switch (cmd) { 369 case TCA_PEDIT_KEY_EX_CMD_SET: 370 val = tkey->val; 371 break; 372 case TCA_PEDIT_KEY_EX_CMD_ADD: 373 val = (*ptr + tkey->val) & ~tkey->mask; 374 break; 375 default: 376 pr_info("tc action pedit bad command (%d)\n", 377 cmd); 378 goto bad; 379 } 380 381 *ptr = ((*ptr & tkey->mask) ^ val); 382 if (ptr == &hdata) 383 skb_store_bits(skb, hoffset + offset, ptr, 4); 384 } 385 386 goto done; 387 } else { 388 WARN(1, "pedit BUG: index %d\n", p->tcf_index); 389 } 390 391 bad: 392 p->tcf_qstats.overlimits++; 393 done: 394 bstats_update(&p->tcf_bstats, skb); 395 spin_unlock(&p->tcf_lock); 396 return p->tcf_action; 397 } 398 399 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 400 int bind, int ref) 401 { 402 unsigned char *b = skb_tail_pointer(skb); 403 struct tcf_pedit *p = to_pedit(a); 404 struct tc_pedit *opt; 405 struct tcf_t t; 406 int s; 407 408 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 409 410 /* netlink spinlocks held above us - must use ATOMIC */ 411 opt = kzalloc(s, GFP_ATOMIC); 412 if (unlikely(!opt)) 413 return -ENOBUFS; 414 415 spin_lock_bh(&p->tcf_lock); 416 memcpy(opt->keys, p->tcfp_keys, 417 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 418 opt->index = p->tcf_index; 419 opt->nkeys = p->tcfp_nkeys; 420 opt->flags = p->tcfp_flags; 421 opt->action = p->tcf_action; 422 opt->refcnt = refcount_read(&p->tcf_refcnt) - ref; 423 opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind; 424 425 if (p->tcfp_keys_ex) { 426 if (tcf_pedit_key_ex_dump(skb, 427 p->tcfp_keys_ex, 428 p->tcfp_nkeys)) 429 goto nla_put_failure; 430 431 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt)) 432 goto nla_put_failure; 433 } else { 434 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt)) 435 goto nla_put_failure; 436 } 437 438 tcf_tm_dump(&t, &p->tcf_tm); 439 if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD)) 440 goto nla_put_failure; 441 spin_unlock_bh(&p->tcf_lock); 442 443 kfree(opt); 444 return skb->len; 445 446 nla_put_failure: 447 spin_unlock_bh(&p->tcf_lock); 448 nlmsg_trim(skb, b); 449 kfree(opt); 450 return -1; 451 } 452 453 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb, 454 struct netlink_callback *cb, int type, 455 const struct tc_action_ops *ops, 456 struct netlink_ext_ack *extack) 457 { 458 struct tc_action_net *tn = net_generic(net, pedit_net_id); 459 460 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 461 } 462 463 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index) 464 { 465 struct tc_action_net *tn = net_generic(net, pedit_net_id); 466 467 return tcf_idr_search(tn, a, index); 468 } 469 470 static struct tc_action_ops act_pedit_ops = { 471 .kind = "pedit", 472 .type = TCA_ACT_PEDIT, 473 .owner = THIS_MODULE, 474 .act = tcf_pedit_act, 475 .dump = tcf_pedit_dump, 476 .cleanup = tcf_pedit_cleanup, 477 .init = tcf_pedit_init, 478 .walk = tcf_pedit_walker, 479 .lookup = tcf_pedit_search, 480 .size = sizeof(struct tcf_pedit), 481 }; 482 483 static __net_init int pedit_init_net(struct net *net) 484 { 485 struct tc_action_net *tn = net_generic(net, pedit_net_id); 486 487 return tc_action_net_init(tn, &act_pedit_ops); 488 } 489 490 static void __net_exit pedit_exit_net(struct list_head *net_list) 491 { 492 tc_action_net_exit(net_list, pedit_net_id); 493 } 494 495 static struct pernet_operations pedit_net_ops = { 496 .init = pedit_init_net, 497 .exit_batch = pedit_exit_net, 498 .id = &pedit_net_id, 499 .size = sizeof(struct tc_action_net), 500 }; 501 502 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 503 MODULE_DESCRIPTION("Generic Packet Editor actions"); 504 MODULE_LICENSE("GPL"); 505 506 static int __init pedit_init_module(void) 507 { 508 return tcf_register_action(&act_pedit_ops, &pedit_net_ops); 509 } 510 511 static void __exit pedit_cleanup_module(void) 512 { 513 tcf_unregister_action(&act_pedit_ops, &pedit_net_ops); 514 } 515 516 module_init(pedit_init_module); 517 module_exit(pedit_cleanup_module); 518