| 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 | |
| 31 | static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly; |
| 32 | struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly; |
| 33 | EXPORT_SYMBOL_GPL(nf_ct_l3protos); |
| 34 | |
| 35 | static DEFINE_MUTEX(nf_ct_proto_mutex); |
| 36 | |
| 37 | #ifdef CONFIG_SYSCTL |
| 38 | static int |
| 39 | nf_ct_register_sysctl(struct net *net, |
| 40 | struct ctl_table_header **header, |
| 41 | const char *path, |
| 42 | struct ctl_table *table) |
| 43 | { |
| 44 | if (*header == NULL) { |
| 45 | *header = register_net_sysctl(net, path, table); |
| 46 | if (*header == NULL) |
| 47 | return -ENOMEM; |
| 48 | } |
| 49 | |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | static void |
| 54 | nf_ct_unregister_sysctl(struct ctl_table_header **header, |
| 55 | struct ctl_table **table, |
| 56 | unsigned int users) |
| 57 | { |
| 58 | if (users > 0) |
| 59 | return; |
| 60 | |
| 61 | unregister_net_sysctl_table(*header); |
| 62 | kfree(*table); |
| 63 | *header = NULL; |
| 64 | *table = NULL; |
| 65 | } |
| 66 | #endif |
| 67 | |
| 68 | struct nf_conntrack_l4proto * |
| 69 | __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) |
| 70 | { |
| 71 | if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) |
| 72 | return &nf_conntrack_l4proto_generic; |
| 73 | |
| 74 | return rcu_dereference(nf_ct_protos[l3proto][l4proto]); |
| 75 | } |
| 76 | EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find); |
| 77 | |
| 78 | /* this is guaranteed to always return a valid protocol helper, since |
| 79 | * it falls back to generic_protocol */ |
| 80 | struct nf_conntrack_l3proto * |
| 81 | nf_ct_l3proto_find_get(u_int16_t l3proto) |
| 82 | { |
| 83 | struct nf_conntrack_l3proto *p; |
| 84 | |
| 85 | rcu_read_lock(); |
| 86 | p = __nf_ct_l3proto_find(l3proto); |
| 87 | if (!try_module_get(p->me)) |
| 88 | p = &nf_conntrack_l3proto_generic; |
| 89 | rcu_read_unlock(); |
| 90 | |
| 91 | return p; |
| 92 | } |
| 93 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get); |
| 94 | |
| 95 | int |
| 96 | nf_ct_l3proto_try_module_get(unsigned short l3proto) |
| 97 | { |
| 98 | int ret; |
| 99 | struct nf_conntrack_l3proto *p; |
| 100 | |
| 101 | retry: p = nf_ct_l3proto_find_get(l3proto); |
| 102 | if (p == &nf_conntrack_l3proto_generic) { |
| 103 | ret = request_module("nf_conntrack-%d", l3proto); |
| 104 | if (!ret) |
| 105 | goto retry; |
| 106 | |
| 107 | return -EPROTOTYPE; |
| 108 | } |
| 109 | |
| 110 | return 0; |
| 111 | } |
| 112 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get); |
| 113 | |
| 114 | void nf_ct_l3proto_module_put(unsigned short l3proto) |
| 115 | { |
| 116 | struct nf_conntrack_l3proto *p; |
| 117 | |
| 118 | /* rcu_read_lock not necessary since the caller holds a reference, but |
| 119 | * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find() |
| 120 | */ |
| 121 | rcu_read_lock(); |
| 122 | p = __nf_ct_l3proto_find(l3proto); |
| 123 | module_put(p->me); |
| 124 | rcu_read_unlock(); |
| 125 | } |
| 126 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); |
| 127 | |
| 128 | struct nf_conntrack_l4proto * |
| 129 | nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num) |
| 130 | { |
| 131 | struct nf_conntrack_l4proto *p; |
| 132 | |
| 133 | rcu_read_lock(); |
| 134 | p = __nf_ct_l4proto_find(l3num, l4num); |
| 135 | if (!try_module_get(p->me)) |
| 136 | p = &nf_conntrack_l4proto_generic; |
| 137 | rcu_read_unlock(); |
| 138 | |
| 139 | return p; |
| 140 | } |
| 141 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get); |
| 142 | |
| 143 | void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p) |
| 144 | { |
| 145 | module_put(p->me); |
| 146 | } |
| 147 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_put); |
| 148 | |
| 149 | static int kill_l3proto(struct nf_conn *i, void *data) |
| 150 | { |
| 151 | return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto; |
| 152 | } |
| 153 | |
| 154 | static int kill_l4proto(struct nf_conn *i, void *data) |
| 155 | { |
| 156 | struct nf_conntrack_l4proto *l4proto; |
| 157 | l4proto = (struct nf_conntrack_l4proto *)data; |
| 158 | return nf_ct_protonum(i) == l4proto->l4proto && |
| 159 | nf_ct_l3num(i) == l4proto->l3proto; |
| 160 | } |
| 161 | |
| 162 | static struct nf_ip_net *nf_ct_l3proto_net(struct net *net, |
| 163 | struct nf_conntrack_l3proto *l3proto) |
| 164 | { |
| 165 | if (l3proto->l3proto == PF_INET) |
| 166 | return &net->ct.nf_ct_proto; |
| 167 | else |
| 168 | return NULL; |
| 169 | } |
| 170 | |
| 171 | static int nf_ct_l3proto_register_sysctl(struct net *net, |
| 172 | struct nf_conntrack_l3proto *l3proto) |
| 173 | { |
| 174 | int err = 0; |
| 175 | struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto); |
| 176 | /* nf_conntrack_l3proto_ipv6 doesn't support sysctl */ |
| 177 | if (in == NULL) |
| 178 | return 0; |
| 179 | |
| 180 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| 181 | if (in->ctl_table != NULL) { |
| 182 | err = nf_ct_register_sysctl(net, |
| 183 | &in->ctl_table_header, |
| 184 | l3proto->ctl_table_path, |
| 185 | in->ctl_table); |
| 186 | if (err < 0) { |
| 187 | kfree(in->ctl_table); |
| 188 | in->ctl_table = NULL; |
| 189 | } |
| 190 | } |
| 191 | #endif |
| 192 | return err; |
| 193 | } |
| 194 | |
| 195 | static void nf_ct_l3proto_unregister_sysctl(struct net *net, |
| 196 | struct nf_conntrack_l3proto *l3proto) |
| 197 | { |
| 198 | struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto); |
| 199 | |
| 200 | if (in == NULL) |
| 201 | return; |
| 202 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| 203 | if (in->ctl_table_header != NULL) |
| 204 | nf_ct_unregister_sysctl(&in->ctl_table_header, |
| 205 | &in->ctl_table, |
| 206 | 0); |
| 207 | #endif |
| 208 | } |
| 209 | |
| 210 | int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto) |
| 211 | { |
| 212 | int ret = 0; |
| 213 | struct nf_conntrack_l3proto *old; |
| 214 | |
| 215 | if (proto->l3proto >= AF_MAX) |
| 216 | return -EBUSY; |
| 217 | |
| 218 | if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size) |
| 219 | return -EINVAL; |
| 220 | |
| 221 | mutex_lock(&nf_ct_proto_mutex); |
| 222 | old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], |
| 223 | lockdep_is_held(&nf_ct_proto_mutex)); |
| 224 | if (old != &nf_conntrack_l3proto_generic) { |
| 225 | ret = -EBUSY; |
| 226 | goto out_unlock; |
| 227 | } |
| 228 | |
| 229 | if (proto->nlattr_tuple_size) |
| 230 | proto->nla_size = 3 * proto->nlattr_tuple_size(); |
| 231 | |
| 232 | rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto); |
| 233 | |
| 234 | out_unlock: |
| 235 | mutex_unlock(&nf_ct_proto_mutex); |
| 236 | return ret; |
| 237 | |
| 238 | } |
| 239 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_register); |
| 240 | |
| 241 | int nf_ct_l3proto_pernet_register(struct net *net, |
| 242 | struct nf_conntrack_l3proto *proto) |
| 243 | { |
| 244 | int ret = 0; |
| 245 | |
| 246 | if (proto->init_net) { |
| 247 | ret = proto->init_net(net); |
| 248 | if (ret < 0) |
| 249 | return ret; |
| 250 | } |
| 251 | |
| 252 | return nf_ct_l3proto_register_sysctl(net, proto); |
| 253 | } |
| 254 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_register); |
| 255 | |
| 256 | void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto) |
| 257 | { |
| 258 | BUG_ON(proto->l3proto >= AF_MAX); |
| 259 | |
| 260 | mutex_lock(&nf_ct_proto_mutex); |
| 261 | BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], |
| 262 | lockdep_is_held(&nf_ct_proto_mutex) |
| 263 | ) != proto); |
| 264 | rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], |
| 265 | &nf_conntrack_l3proto_generic); |
| 266 | mutex_unlock(&nf_ct_proto_mutex); |
| 267 | |
| 268 | synchronize_rcu(); |
| 269 | } |
| 270 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister); |
| 271 | |
| 272 | void nf_ct_l3proto_pernet_unregister(struct net *net, |
| 273 | struct nf_conntrack_l3proto *proto) |
| 274 | { |
| 275 | nf_ct_l3proto_unregister_sysctl(net, proto); |
| 276 | |
| 277 | /* Remove all contrack entries for this protocol */ |
| 278 | nf_ct_iterate_cleanup(net, kill_l3proto, proto, 0, 0); |
| 279 | } |
| 280 | EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_unregister); |
| 281 | |
| 282 | static struct nf_proto_net *nf_ct_l4proto_net(struct net *net, |
| 283 | struct nf_conntrack_l4proto *l4proto) |
| 284 | { |
| 285 | if (l4proto->get_net_proto) { |
| 286 | /* statically built-in protocols use static per-net */ |
| 287 | return l4proto->get_net_proto(net); |
| 288 | } else if (l4proto->net_id) { |
| 289 | /* ... and loadable protocols use dynamic per-net */ |
| 290 | return net_generic(net, *l4proto->net_id); |
| 291 | } |
| 292 | return NULL; |
| 293 | } |
| 294 | |
| 295 | static |
| 296 | int nf_ct_l4proto_register_sysctl(struct net *net, |
| 297 | struct nf_proto_net *pn, |
| 298 | struct nf_conntrack_l4proto *l4proto) |
| 299 | { |
| 300 | int err = 0; |
| 301 | |
| 302 | #ifdef CONFIG_SYSCTL |
| 303 | if (pn->ctl_table != NULL) { |
| 304 | err = nf_ct_register_sysctl(net, |
| 305 | &pn->ctl_table_header, |
| 306 | "net/netfilter", |
| 307 | pn->ctl_table); |
| 308 | if (err < 0) { |
| 309 | if (!pn->users) { |
| 310 | kfree(pn->ctl_table); |
| 311 | pn->ctl_table = NULL; |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| 316 | if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_table != NULL) { |
| 317 | if (err < 0) { |
| 318 | nf_ct_kfree_compat_sysctl_table(pn); |
| 319 | goto out; |
| 320 | } |
| 321 | err = nf_ct_register_sysctl(net, |
| 322 | &pn->ctl_compat_header, |
| 323 | "net/ipv4/netfilter", |
| 324 | pn->ctl_compat_table); |
| 325 | if (err == 0) |
| 326 | goto out; |
| 327 | |
| 328 | nf_ct_kfree_compat_sysctl_table(pn); |
| 329 | nf_ct_unregister_sysctl(&pn->ctl_table_header, |
| 330 | &pn->ctl_table, |
| 331 | pn->users); |
| 332 | } |
| 333 | out: |
| 334 | #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| 335 | #endif /* CONFIG_SYSCTL */ |
| 336 | return err; |
| 337 | } |
| 338 | |
| 339 | static |
| 340 | void nf_ct_l4proto_unregister_sysctl(struct net *net, |
| 341 | struct nf_proto_net *pn, |
| 342 | struct nf_conntrack_l4proto *l4proto) |
| 343 | { |
| 344 | #ifdef CONFIG_SYSCTL |
| 345 | if (pn->ctl_table_header != NULL) |
| 346 | nf_ct_unregister_sysctl(&pn->ctl_table_header, |
| 347 | &pn->ctl_table, |
| 348 | pn->users); |
| 349 | |
| 350 | #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| 351 | if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_header != NULL) |
| 352 | nf_ct_unregister_sysctl(&pn->ctl_compat_header, |
| 353 | &pn->ctl_compat_table, |
| 354 | 0); |
| 355 | #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| 356 | #endif /* CONFIG_SYSCTL */ |
| 357 | } |
| 358 | |
| 359 | /* FIXME: Allow NULL functions and sub in pointers to generic for |
| 360 | them. --RR */ |
| 361 | int nf_ct_l4proto_register(struct nf_conntrack_l4proto *l4proto) |
| 362 | { |
| 363 | int ret = 0; |
| 364 | |
| 365 | if (l4proto->l3proto >= PF_MAX) |
| 366 | return -EBUSY; |
| 367 | |
| 368 | if ((l4proto->to_nlattr && !l4proto->nlattr_size) |
| 369 | || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size)) |
| 370 | return -EINVAL; |
| 371 | |
| 372 | mutex_lock(&nf_ct_proto_mutex); |
| 373 | if (!nf_ct_protos[l4proto->l3proto]) { |
| 374 | /* l3proto may be loaded latter. */ |
| 375 | struct nf_conntrack_l4proto __rcu **proto_array; |
| 376 | int i; |
| 377 | |
| 378 | proto_array = kmalloc(MAX_NF_CT_PROTO * |
| 379 | sizeof(struct nf_conntrack_l4proto *), |
| 380 | GFP_KERNEL); |
| 381 | if (proto_array == NULL) { |
| 382 | ret = -ENOMEM; |
| 383 | goto out_unlock; |
| 384 | } |
| 385 | |
| 386 | for (i = 0; i < MAX_NF_CT_PROTO; i++) |
| 387 | RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic); |
| 388 | |
| 389 | /* Before making proto_array visible to lockless readers, |
| 390 | * we must make sure its content is committed to memory. |
| 391 | */ |
| 392 | smp_wmb(); |
| 393 | |
| 394 | nf_ct_protos[l4proto->l3proto] = proto_array; |
| 395 | } else if (rcu_dereference_protected( |
| 396 | nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| 397 | lockdep_is_held(&nf_ct_proto_mutex) |
| 398 | ) != &nf_conntrack_l4proto_generic) { |
| 399 | ret = -EBUSY; |
| 400 | goto out_unlock; |
| 401 | } |
| 402 | |
| 403 | l4proto->nla_size = 0; |
| 404 | if (l4proto->nlattr_size) |
| 405 | l4proto->nla_size += l4proto->nlattr_size(); |
| 406 | if (l4proto->nlattr_tuple_size) |
| 407 | l4proto->nla_size += 3 * l4proto->nlattr_tuple_size(); |
| 408 | |
| 409 | rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| 410 | l4proto); |
| 411 | out_unlock: |
| 412 | mutex_unlock(&nf_ct_proto_mutex); |
| 413 | return ret; |
| 414 | } |
| 415 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_register); |
| 416 | |
| 417 | int nf_ct_l4proto_pernet_register(struct net *net, |
| 418 | struct nf_conntrack_l4proto *l4proto) |
| 419 | { |
| 420 | int ret = 0; |
| 421 | struct nf_proto_net *pn = NULL; |
| 422 | |
| 423 | if (l4proto->init_net) { |
| 424 | ret = l4proto->init_net(net, l4proto->l3proto); |
| 425 | if (ret < 0) |
| 426 | goto out; |
| 427 | } |
| 428 | |
| 429 | pn = nf_ct_l4proto_net(net, l4proto); |
| 430 | if (pn == NULL) |
| 431 | goto out; |
| 432 | |
| 433 | ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto); |
| 434 | if (ret < 0) |
| 435 | goto out; |
| 436 | |
| 437 | pn->users++; |
| 438 | out: |
| 439 | return ret; |
| 440 | } |
| 441 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register); |
| 442 | |
| 443 | void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) |
| 444 | { |
| 445 | BUG_ON(l4proto->l3proto >= PF_MAX); |
| 446 | |
| 447 | mutex_lock(&nf_ct_proto_mutex); |
| 448 | BUG_ON(rcu_dereference_protected( |
| 449 | nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| 450 | lockdep_is_held(&nf_ct_proto_mutex) |
| 451 | ) != l4proto); |
| 452 | rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| 453 | &nf_conntrack_l4proto_generic); |
| 454 | mutex_unlock(&nf_ct_proto_mutex); |
| 455 | |
| 456 | synchronize_rcu(); |
| 457 | } |
| 458 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister); |
| 459 | |
| 460 | void nf_ct_l4proto_pernet_unregister(struct net *net, |
| 461 | struct nf_conntrack_l4proto *l4proto) |
| 462 | { |
| 463 | struct nf_proto_net *pn = NULL; |
| 464 | |
| 465 | pn = nf_ct_l4proto_net(net, l4proto); |
| 466 | if (pn == NULL) |
| 467 | return; |
| 468 | |
| 469 | pn->users--; |
| 470 | nf_ct_l4proto_unregister_sysctl(net, pn, l4proto); |
| 471 | |
| 472 | /* Remove all contrack entries for this protocol */ |
| 473 | nf_ct_iterate_cleanup(net, kill_l4proto, l4proto, 0, 0); |
| 474 | } |
| 475 | EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister); |
| 476 | |
| 477 | int nf_conntrack_proto_pernet_init(struct net *net) |
| 478 | { |
| 479 | int err; |
| 480 | struct nf_proto_net *pn = nf_ct_l4proto_net(net, |
| 481 | &nf_conntrack_l4proto_generic); |
| 482 | |
| 483 | err = nf_conntrack_l4proto_generic.init_net(net, |
| 484 | nf_conntrack_l4proto_generic.l3proto); |
| 485 | if (err < 0) |
| 486 | return err; |
| 487 | err = nf_ct_l4proto_register_sysctl(net, |
| 488 | pn, |
| 489 | &nf_conntrack_l4proto_generic); |
| 490 | if (err < 0) |
| 491 | return err; |
| 492 | |
| 493 | pn->users++; |
| 494 | return 0; |
| 495 | } |
| 496 | |
| 497 | void nf_conntrack_proto_pernet_fini(struct net *net) |
| 498 | { |
| 499 | struct nf_proto_net *pn = nf_ct_l4proto_net(net, |
| 500 | &nf_conntrack_l4proto_generic); |
| 501 | |
| 502 | pn->users--; |
| 503 | nf_ct_l4proto_unregister_sysctl(net, |
| 504 | pn, |
| 505 | &nf_conntrack_l4proto_generic); |
| 506 | } |
| 507 | |
| 508 | int nf_conntrack_proto_init(void) |
| 509 | { |
| 510 | unsigned int i; |
| 511 | for (i = 0; i < AF_MAX; i++) |
| 512 | rcu_assign_pointer(nf_ct_l3protos[i], |
| 513 | &nf_conntrack_l3proto_generic); |
| 514 | return 0; |
| 515 | } |
| 516 | |
| 517 | void nf_conntrack_proto_fini(void) |
| 518 | { |
| 519 | unsigned int i; |
| 520 | /* free l3proto protocol tables */ |
| 521 | for (i = 0; i < PF_MAX; i++) |
| 522 | kfree(nf_ct_protos[i]); |
| 523 | } |