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); 488 489