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); 511