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