1 /* L3/L4 protocol support for nf_conntrack. */ 2 3 /* (C) 1999-2001 Paul `Rusty' Russell 4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/types.h> 14 #include <linux/netfilter.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <linux/mutex.h> 18 #include <linux/vmalloc.h> 19 #include <linux/stddef.h> 20 #include <linux/err.h> 21 #include <linux/percpu.h> 22 #include <linux/notifier.h> 23 #include <linux/kernel.h> 24 #include <linux/netdevice.h> 25 26 #include <net/netfilter/nf_conntrack.h> 27 #include <net/netfilter/nf_conntrack_l3proto.h> 28 #include <net/netfilter/nf_conntrack_l4proto.h> 29 #include <net/netfilter/nf_conntrack_core.h> 30 #include <net/netfilter/nf_log.h> 31 32 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[NFPROTO_NUMPROTO] __read_mostly; 33 struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[NFPROTO_NUMPROTO] __read_mostly; 34 EXPORT_SYMBOL_GPL(nf_ct_l3protos); 35 36 static DEFINE_MUTEX(nf_ct_proto_mutex); 37 38 #ifdef CONFIG_SYSCTL 39 static int 40 nf_ct_register_sysctl(struct net *net, 41 struct ctl_table_header **header, 42 const char *path, 43 struct ctl_table *table) 44 { 45 if (*header == NULL) { 46 *header = register_net_sysctl(net, path, table); 47 if (*header == NULL) 48 return -ENOMEM; 49 } 50 51 return 0; 52 } 53 54 static void 55 nf_ct_unregister_sysctl(struct ctl_table_header **header, 56 struct ctl_table **table, 57 unsigned int users) 58 { 59 if (users > 0) 60 return; 61 62 unregister_net_sysctl_table(*header); 63 kfree(*table); 64 *header = NULL; 65 *table = NULL; 66 } 67 68 __printf(5, 6) 69 void nf_l4proto_log_invalid(const struct sk_buff *skb, 70 struct net *net, 71 u16 pf, u8 protonum, 72 const char *fmt, ...) 73 { 74 struct va_format vaf; 75 va_list args; 76 77 if (net->ct.sysctl_log_invalid != protonum || 78 net->ct.sysctl_log_invalid != IPPROTO_RAW) 79 return; 80 81 va_start(args, fmt); 82 vaf.fmt = fmt; 83 vaf.va = &args; 84 85 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, 86 "nf_ct_proto_%d: %pV ", protonum, &vaf); 87 va_end(args); 88 } 89 EXPORT_SYMBOL_GPL(nf_l4proto_log_invalid); 90 91 __printf(3, 4) 92 void nf_ct_l4proto_log_invalid(const struct sk_buff *skb, 93 const struct nf_conn *ct, 94 const char *fmt, ...) 95 { 96 struct va_format vaf; 97 struct net *net; 98 va_list args; 99 100 net = nf_ct_net(ct); 101 if (likely(net->ct.sysctl_log_invalid == 0)) 102 return; 103 104 va_start(args, fmt); 105 vaf.fmt = fmt; 106 vaf.va = &args; 107 108 nf_l4proto_log_invalid(skb, net, nf_ct_l3num(ct), 109 nf_ct_protonum(ct), "%pV", &vaf); 110 va_end(args); 111 } 112 EXPORT_SYMBOL_GPL(nf_ct_l4proto_log_invalid); 113 #endif 114 115 const struct nf_conntrack_l4proto * 116 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) 117 { 118 if (unlikely(l3proto >= NFPROTO_NUMPROTO || nf_ct_protos[l3proto] == NULL)) 119 return &nf_conntrack_l4proto_generic; 120 121 return rcu_dereference(nf_ct_protos[l3proto][l4proto]); 122 } 123 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find); 124 125 /* this is guaranteed to always return a valid protocol helper, since 126 * it falls back to generic_protocol */ 127 const struct nf_conntrack_l3proto * 128 nf_ct_l3proto_find_get(u_int16_t l3proto) 129 { 130 struct nf_conntrack_l3proto *p; 131 132 rcu_read_lock(); 133 p = __nf_ct_l3proto_find(l3proto); 134 if (!try_module_get(p->me)) 135 p = &nf_conntrack_l3proto_generic; 136 rcu_read_unlock(); 137 138 return p; 139 } 140 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get); 141 142 int 143 nf_ct_l3proto_try_module_get(unsigned short l3proto) 144 { 145 const struct nf_conntrack_l3proto *p; 146 int ret; 147 148 retry: p = nf_ct_l3proto_find_get(l3proto); 149 if (p == &nf_conntrack_l3proto_generic) { 150 ret = request_module("nf_conntrack-%d", l3proto); 151 if (!ret) 152 goto retry; 153 154 return -EPROTOTYPE; 155 } 156 157 return 0; 158 } 159 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get); 160 161 void nf_ct_l3proto_module_put(unsigned short l3proto) 162 { 163 struct nf_conntrack_l3proto *p; 164 165 /* rcu_read_lock not necessary since the caller holds a reference, but 166 * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find() 167 */ 168 rcu_read_lock(); 169 p = __nf_ct_l3proto_find(l3proto); 170 module_put(p->me); 171 rcu_read_unlock(); 172 } 173 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); 174 175 static int nf_ct_netns_do_get(struct net *net, u8 nfproto) 176 { 177 const struct nf_conntrack_l3proto *l3proto; 178 int ret; 179 180 might_sleep(); 181 182 ret = nf_ct_l3proto_try_module_get(nfproto); 183 if (ret < 0) 184 return ret; 185 186 /* we already have a reference, can't fail */ 187 rcu_read_lock(); 188 l3proto = __nf_ct_l3proto_find(nfproto); 189 rcu_read_unlock(); 190 191 if (!l3proto->net_ns_get) 192 return 0; 193 194 ret = l3proto->net_ns_get(net); 195 if (ret < 0) 196 nf_ct_l3proto_module_put(nfproto); 197 198 return ret; 199 } 200 201 int nf_ct_netns_get(struct net *net, u8 nfproto) 202 { 203 int err; 204 205 if (nfproto == NFPROTO_INET) { 206 err = nf_ct_netns_do_get(net, NFPROTO_IPV4); 207 if (err < 0) 208 goto err1; 209 err = nf_ct_netns_do_get(net, NFPROTO_IPV6); 210 if (err < 0) 211 goto err2; 212 } else { 213 err = nf_ct_netns_do_get(net, nfproto); 214 if (err < 0) 215 goto err1; 216 } 217 return 0; 218 219 err2: 220 nf_ct_netns_put(net, NFPROTO_IPV4); 221 err1: 222 return err; 223 } 224 EXPORT_SYMBOL_GPL(nf_ct_netns_get); 225 226 static void nf_ct_netns_do_put(struct net *net, u8 nfproto) 227 { 228 const struct nf_conntrack_l3proto *l3proto; 229 230 might_sleep(); 231 232 /* same as nf_conntrack_netns_get(), reference assumed */ 233 rcu_read_lock(); 234 l3proto = __nf_ct_l3proto_find(nfproto); 235 rcu_read_unlock(); 236 237 if (WARN_ON(!l3proto)) 238 return; 239 240 if (l3proto->net_ns_put) 241 l3proto->net_ns_put(net); 242 243 nf_ct_l3proto_module_put(nfproto); 244 } 245 246 void nf_ct_netns_put(struct net *net, uint8_t nfproto) 247 { 248 if (nfproto == NFPROTO_INET) { 249 nf_ct_netns_do_put(net, NFPROTO_IPV4); 250 nf_ct_netns_do_put(net, NFPROTO_IPV6); 251 } else 252 nf_ct_netns_do_put(net, nfproto); 253 } 254 EXPORT_SYMBOL_GPL(nf_ct_netns_put); 255 256 const struct nf_conntrack_l4proto * 257 nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num) 258 { 259 const struct nf_conntrack_l4proto *p; 260 261 rcu_read_lock(); 262 p = __nf_ct_l4proto_find(l3num, l4num); 263 if (!try_module_get(p->me)) 264 p = &nf_conntrack_l4proto_generic; 265 rcu_read_unlock(); 266 267 return p; 268 } 269 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get); 270 271 void nf_ct_l4proto_put(const struct nf_conntrack_l4proto *p) 272 { 273 module_put(p->me); 274 } 275 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put); 276 277 static int kill_l3proto(struct nf_conn *i, void *data) 278 { 279 return nf_ct_l3num(i) == ((const struct nf_conntrack_l3proto *)data)->l3proto; 280 } 281 282 static int kill_l4proto(struct nf_conn *i, void *data) 283 { 284 const struct nf_conntrack_l4proto *l4proto; 285 l4proto = data; 286 return nf_ct_protonum(i) == l4proto->l4proto && 287 nf_ct_l3num(i) == l4proto->l3proto; 288 } 289 290 int nf_ct_l3proto_register(const struct nf_conntrack_l3proto *proto) 291 { 292 int ret = 0; 293 struct nf_conntrack_l3proto *old; 294 295 if (proto->l3proto >= NFPROTO_NUMPROTO) 296 return -EBUSY; 297 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 298 if (proto->tuple_to_nlattr && proto->nla_size == 0) 299 return -EINVAL; 300 #endif 301 mutex_lock(&nf_ct_proto_mutex); 302 old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], 303 lockdep_is_held(&nf_ct_proto_mutex)); 304 if (old != &nf_conntrack_l3proto_generic) { 305 ret = -EBUSY; 306 goto out_unlock; 307 } 308 309 rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto); 310 311 out_unlock: 312 mutex_unlock(&nf_ct_proto_mutex); 313 return ret; 314 315 } 316 EXPORT_SYMBOL_GPL(nf_ct_l3proto_register); 317 318 void nf_ct_l3proto_unregister(const struct nf_conntrack_l3proto *proto) 319 { 320 BUG_ON(proto->l3proto >= NFPROTO_NUMPROTO); 321 322 mutex_lock(&nf_ct_proto_mutex); 323 BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], 324 lockdep_is_held(&nf_ct_proto_mutex) 325 ) != proto); 326 rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], 327 &nf_conntrack_l3proto_generic); 328 mutex_unlock(&nf_ct_proto_mutex); 329 330 synchronize_rcu(); 331 /* Remove all contrack entries for this protocol */ 332 nf_ct_iterate_destroy(kill_l3proto, (void*)proto); 333 } 334 EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister); 335 336 static struct nf_proto_net *nf_ct_l4proto_net(struct net *net, 337 const struct nf_conntrack_l4proto *l4proto) 338 { 339 if (l4proto->get_net_proto) { 340 /* statically built-in protocols use static per-net */ 341 return l4proto->get_net_proto(net); 342 } else if (l4proto->net_id) { 343 /* ... and loadable protocols use dynamic per-net */ 344 return net_generic(net, *l4proto->net_id); 345 } 346 return NULL; 347 } 348 349 static 350 int nf_ct_l4proto_register_sysctl(struct net *net, 351 struct nf_proto_net *pn, 352 const struct nf_conntrack_l4proto *l4proto) 353 { 354 int err = 0; 355 356 #ifdef CONFIG_SYSCTL 357 if (pn->ctl_table != NULL) { 358 err = nf_ct_register_sysctl(net, 359 &pn->ctl_table_header, 360 "net/netfilter", 361 pn->ctl_table); 362 if (err < 0) { 363 if (!pn->users) { 364 kfree(pn->ctl_table); 365 pn->ctl_table = NULL; 366 } 367 } 368 } 369 #endif /* CONFIG_SYSCTL */ 370 return err; 371 } 372 373 static 374 void nf_ct_l4proto_unregister_sysctl(struct net *net, 375 struct nf_proto_net *pn, 376 const struct nf_conntrack_l4proto *l4proto) 377 { 378 #ifdef CONFIG_SYSCTL 379 if (pn->ctl_table_header != NULL) 380 nf_ct_unregister_sysctl(&pn->ctl_table_header, 381 &pn->ctl_table, 382 pn->users); 383 #endif /* CONFIG_SYSCTL */ 384 } 385 386 /* FIXME: Allow NULL functions and sub in pointers to generic for 387 them. --RR */ 388 int nf_ct_l4proto_register_one(const struct nf_conntrack_l4proto *l4proto) 389 { 390 int ret = 0; 391 392 if (l4proto->l3proto >= ARRAY_SIZE(nf_ct_protos)) 393 return -EBUSY; 394 395 if ((l4proto->to_nlattr && l4proto->nlattr_size == 0) || 396 (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size)) 397 return -EINVAL; 398 399 mutex_lock(&nf_ct_proto_mutex); 400 if (!nf_ct_protos[l4proto->l3proto]) { 401 /* l3proto may be loaded latter. */ 402 struct nf_conntrack_l4proto __rcu **proto_array; 403 int i; 404 405 proto_array = 406 kmalloc_array(MAX_NF_CT_PROTO, 407 sizeof(struct nf_conntrack_l4proto *), 408 GFP_KERNEL); 409 if (proto_array == NULL) { 410 ret = -ENOMEM; 411 goto out_unlock; 412 } 413 414 for (i = 0; i < MAX_NF_CT_PROTO; i++) 415 RCU_INIT_POINTER(proto_array[i], 416 &nf_conntrack_l4proto_generic); 417 418 /* Before making proto_array visible to lockless readers, 419 * we must make sure its content is committed to memory. 420 */ 421 smp_wmb(); 422 423 nf_ct_protos[l4proto->l3proto] = proto_array; 424 } else if (rcu_dereference_protected( 425 nf_ct_protos[l4proto->l3proto][l4proto->l4proto], 426 lockdep_is_held(&nf_ct_proto_mutex) 427 ) != &nf_conntrack_l4proto_generic) { 428 ret = -EBUSY; 429 goto out_unlock; 430 } 431 432 rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], 433 l4proto); 434 out_unlock: 435 mutex_unlock(&nf_ct_proto_mutex); 436 return ret; 437 } 438 EXPORT_SYMBOL_GPL(nf_ct_l4proto_register_one); 439 440 int nf_ct_l4proto_pernet_register_one(struct net *net, 441 const struct nf_conntrack_l4proto *l4proto) 442 { 443 int ret = 0; 444 struct nf_proto_net *pn = NULL; 445 446 if (l4proto->init_net) { 447 ret = l4proto->init_net(net, l4proto->l3proto); 448 if (ret < 0) 449 goto out; 450 } 451 452 pn = nf_ct_l4proto_net(net, l4proto); 453 if (pn == NULL) 454 goto out; 455 456 ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto); 457 if (ret < 0) 458 goto out; 459 460 pn->users++; 461 out: 462 return ret; 463 } 464 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register_one); 465 466 static void __nf_ct_l4proto_unregister_one(const struct nf_conntrack_l4proto *l4proto) 467 468 { 469 BUG_ON(l4proto->l3proto >= ARRAY_SIZE(nf_ct_protos)); 470 471 BUG_ON(rcu_dereference_protected( 472 nf_ct_protos[l4proto->l3proto][l4proto->l4proto], 473 lockdep_is_held(&nf_ct_proto_mutex) 474 ) != l4proto); 475 rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], 476 &nf_conntrack_l4proto_generic); 477 } 478 479 void nf_ct_l4proto_unregister_one(const struct nf_conntrack_l4proto *l4proto) 480 { 481 mutex_lock(&nf_ct_proto_mutex); 482 __nf_ct_l4proto_unregister_one(l4proto); 483 mutex_unlock(&nf_ct_proto_mutex); 484 485 synchronize_rcu(); 486 } 487 EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister_one); 488 489 void nf_ct_l4proto_pernet_unregister_one(struct net *net, 490 const struct nf_conntrack_l4proto *l4proto) 491 { 492 struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto); 493 494 if (pn == NULL) 495 return; 496 497 pn->users--; 498 nf_ct_l4proto_unregister_sysctl(net, pn, l4proto); 499 } 500 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister_one); 501 502 int nf_ct_l4proto_register(const struct nf_conntrack_l4proto * const l4proto[], 503 unsigned int num_proto) 504 { 505 int ret = -EINVAL, ver; 506 unsigned int i; 507 508 for (i = 0; i < num_proto; i++) { 509 ret = nf_ct_l4proto_register_one(l4proto[i]); 510 if (ret < 0) 511 break; 512 } 513 if (i != num_proto) { 514 ver = l4proto[i]->l3proto == PF_INET6 ? 6 : 4; 515 pr_err("nf_conntrack_ipv%d: can't register l4 %d proto.\n", 516 ver, l4proto[i]->l4proto); 517 nf_ct_l4proto_unregister(l4proto, i); 518 } 519 return ret; 520 } 521 EXPORT_SYMBOL_GPL(nf_ct_l4proto_register); 522 523 int nf_ct_l4proto_pernet_register(struct net *net, 524 const struct nf_conntrack_l4proto *const l4proto[], 525 unsigned int num_proto) 526 { 527 int ret = -EINVAL; 528 unsigned int i; 529 530 for (i = 0; i < num_proto; i++) { 531 ret = nf_ct_l4proto_pernet_register_one(net, l4proto[i]); 532 if (ret < 0) 533 break; 534 } 535 if (i != num_proto) { 536 pr_err("nf_conntrack_proto_%d %d: pernet registration failed\n", 537 l4proto[i]->l4proto, 538 l4proto[i]->l3proto == PF_INET6 ? 6 : 4); 539 nf_ct_l4proto_pernet_unregister(net, l4proto, i); 540 } 541 return ret; 542 } 543 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register); 544 545 void nf_ct_l4proto_unregister(const struct nf_conntrack_l4proto * const l4proto[], 546 unsigned int num_proto) 547 { 548 mutex_lock(&nf_ct_proto_mutex); 549 while (num_proto-- != 0) 550 __nf_ct_l4proto_unregister_one(l4proto[num_proto]); 551 mutex_unlock(&nf_ct_proto_mutex); 552 553 synchronize_net(); 554 /* Remove all contrack entries for this protocol */ 555 nf_ct_iterate_destroy(kill_l4proto, (void *)l4proto); 556 } 557 EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister); 558 559 void nf_ct_l4proto_pernet_unregister(struct net *net, 560 const struct nf_conntrack_l4proto *const l4proto[], 561 unsigned int num_proto) 562 { 563 while (num_proto-- != 0) 564 nf_ct_l4proto_pernet_unregister_one(net, l4proto[num_proto]); 565 } 566 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister); 567 568 int nf_conntrack_proto_pernet_init(struct net *net) 569 { 570 int err; 571 struct nf_proto_net *pn = nf_ct_l4proto_net(net, 572 &nf_conntrack_l4proto_generic); 573 574 err = nf_conntrack_l4proto_generic.init_net(net, 575 nf_conntrack_l4proto_generic.l3proto); 576 if (err < 0) 577 return err; 578 err = nf_ct_l4proto_register_sysctl(net, 579 pn, 580 &nf_conntrack_l4proto_generic); 581 if (err < 0) 582 return err; 583 584 pn->users++; 585 return 0; 586 } 587 588 void nf_conntrack_proto_pernet_fini(struct net *net) 589 { 590 struct nf_proto_net *pn = nf_ct_l4proto_net(net, 591 &nf_conntrack_l4proto_generic); 592 593 pn->users--; 594 nf_ct_l4proto_unregister_sysctl(net, 595 pn, 596 &nf_conntrack_l4proto_generic); 597 } 598 599 int nf_conntrack_proto_init(void) 600 { 601 unsigned int i; 602 for (i = 0; i < NFPROTO_NUMPROTO; i++) 603 rcu_assign_pointer(nf_ct_l3protos[i], 604 &nf_conntrack_l3proto_generic); 605 return 0; 606 } 607 608 void nf_conntrack_proto_fini(void) 609 { 610 unsigned int i; 611 /* free l3proto protocol tables */ 612 for (i = 0; i < ARRAY_SIZE(nf_ct_protos); i++) 613 kfree(nf_ct_protos[i]); 614 } 615