1/* 2 * Copyright (c) 2010 Patrick McHardy <kaber@trash.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9#include <linux/module.h> 10#include <linux/gfp.h> 11#include <linux/skbuff.h> 12#include <linux/netfilter_ipv4/ip_tables.h> 13#include <linux/netfilter_ipv6/ip6_tables.h> 14#include <linux/netfilter/x_tables.h> 15#include <linux/netfilter/xt_CT.h> 16#include <net/netfilter/nf_conntrack.h> 17#include <net/netfilter/nf_conntrack_l4proto.h> 18#include <net/netfilter/nf_conntrack_helper.h> 19#include <net/netfilter/nf_conntrack_ecache.h> 20#include <net/netfilter/nf_conntrack_timeout.h> 21#include <net/netfilter/nf_conntrack_zones.h> 22 23static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct) 24{ 25 /* Previously seen (loopback)? Ignore. */ 26 if (skb->nfct != NULL) 27 return XT_CONTINUE; 28 29 /* special case the untracked ct : we want the percpu object */ 30 if (!ct) 31 ct = nf_ct_untracked_get(); 32 atomic_inc(&ct->ct_general.use); 33 skb->nfct = &ct->ct_general; 34 skb->nfctinfo = IP_CT_NEW; 35 36 return XT_CONTINUE; 37} 38 39static unsigned int xt_ct_target_v0(struct sk_buff *skb, 40 const struct xt_action_param *par) 41{ 42 const struct xt_ct_target_info *info = par->targinfo; 43 struct nf_conn *ct = info->ct; 44 45 return xt_ct_target(skb, ct); 46} 47 48static unsigned int xt_ct_target_v1(struct sk_buff *skb, 49 const struct xt_action_param *par) 50{ 51 const struct xt_ct_target_info_v1 *info = par->targinfo; 52 struct nf_conn *ct = info->ct; 53 54 return xt_ct_target(skb, ct); 55} 56 57static u8 xt_ct_find_proto(const struct xt_tgchk_param *par) 58{ 59 if (par->family == NFPROTO_IPV4) { 60 const struct ipt_entry *e = par->entryinfo; 61 62 if (e->ip.invflags & IPT_INV_PROTO) 63 return 0; 64 return e->ip.proto; 65 } else if (par->family == NFPROTO_IPV6) { 66 const struct ip6t_entry *e = par->entryinfo; 67 68 if (e->ipv6.invflags & IP6T_INV_PROTO) 69 return 0; 70 return e->ipv6.proto; 71 } else 72 return 0; 73} 74 75static int 76xt_ct_set_helper(struct nf_conn *ct, const char *helper_name, 77 const struct xt_tgchk_param *par) 78{ 79 struct nf_conntrack_helper *helper; 80 struct nf_conn_help *help; 81 u8 proto; 82 83 proto = xt_ct_find_proto(par); 84 if (!proto) { 85 pr_info("You must specify a L4 protocol, and not use " 86 "inversions on it.\n"); 87 return -ENOENT; 88 } 89 90 helper = nf_conntrack_helper_try_module_get(helper_name, par->family, 91 proto); 92 if (helper == NULL) { 93 pr_info("No such helper \"%s\"\n", helper_name); 94 return -ENOENT; 95 } 96 97 help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL); 98 if (help == NULL) { 99 module_put(helper->me); 100 return -ENOMEM; 101 } 102 103 help->helper = helper; 104 return 0; 105} 106 107#ifdef CONFIG_NF_CONNTRACK_TIMEOUT 108static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout) 109{ 110 typeof(nf_ct_timeout_put_hook) timeout_put; 111 112 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 113 if (timeout_put) 114 timeout_put(timeout); 115} 116#endif 117 118static int 119xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par, 120 const char *timeout_name) 121{ 122#ifdef CONFIG_NF_CONNTRACK_TIMEOUT 123 typeof(nf_ct_timeout_find_get_hook) timeout_find_get; 124 struct ctnl_timeout *timeout; 125 struct nf_conn_timeout *timeout_ext; 126 struct nf_conntrack_l4proto *l4proto; 127 int ret = 0; 128 u8 proto; 129 130 rcu_read_lock(); 131 timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook); 132 if (timeout_find_get == NULL) { 133 ret = -ENOENT; 134 pr_info("Timeout policy base is empty\n"); 135 goto out; 136 } 137 138 proto = xt_ct_find_proto(par); 139 if (!proto) { 140 ret = -EINVAL; 141 pr_info("You must specify a L4 protocol, and not use " 142 "inversions on it.\n"); 143 goto out; 144 } 145 146 timeout = timeout_find_get(timeout_name); 147 if (timeout == NULL) { 148 ret = -ENOENT; 149 pr_info("No such timeout policy \"%s\"\n", timeout_name); 150 goto out; 151 } 152 153 if (timeout->l3num != par->family) { 154 ret = -EINVAL; 155 pr_info("Timeout policy `%s' can only be used by L3 protocol " 156 "number %d\n", timeout_name, timeout->l3num); 157 goto err_put_timeout; 158 } 159 /* Make sure the timeout policy matches any existing protocol tracker, 160 * otherwise default to generic. 161 */ 162 l4proto = __nf_ct_l4proto_find(par->family, proto); 163 if (timeout->l4proto->l4proto != l4proto->l4proto) { 164 ret = -EINVAL; 165 pr_info("Timeout policy `%s' can only be used by L4 protocol " 166 "number %d\n", 167 timeout_name, timeout->l4proto->l4proto); 168 goto err_put_timeout; 169 } 170 timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC); 171 if (timeout_ext == NULL) 172 ret = -ENOMEM; 173 174err_put_timeout: 175 __xt_ct_tg_timeout_put(timeout); 176out: 177 rcu_read_unlock(); 178 return ret; 179#else 180 return -EOPNOTSUPP; 181#endif 182} 183 184static int xt_ct_tg_check(const struct xt_tgchk_param *par, 185 struct xt_ct_target_info_v1 *info) 186{ 187 struct nf_conntrack_tuple t; 188 struct nf_conn *ct; 189 int ret = -EOPNOTSUPP; 190 191 if (info->flags & XT_CT_NOTRACK) { 192 ct = NULL; 193 goto out; 194 } 195 196#ifndef CONFIG_NF_CONNTRACK_ZONES 197 if (info->zone) 198 goto err1; 199#endif 200 201 ret = nf_ct_l3proto_try_module_get(par->family); 202 if (ret < 0) 203 goto err1; 204 205 memset(&t, 0, sizeof(t)); 206 ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL); 207 ret = PTR_ERR(ct); 208 if (IS_ERR(ct)) 209 goto err2; 210 211 ret = 0; 212 if ((info->ct_events || info->exp_events) && 213 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, 214 GFP_KERNEL)) { 215 ret = -EINVAL; 216 goto err3; 217 } 218 219 if (info->helper[0]) { 220 ret = xt_ct_set_helper(ct, info->helper, par); 221 if (ret < 0) 222 goto err3; 223 } 224 225 if (info->timeout[0]) { 226 ret = xt_ct_set_timeout(ct, par, info->timeout); 227 if (ret < 0) 228 goto err3; 229 } 230 231 nf_conntrack_tmpl_insert(par->net, ct); 232out: 233 info->ct = ct; 234 return 0; 235 236err3: 237 nf_conntrack_free(ct); 238err2: 239 nf_ct_l3proto_module_put(par->family); 240err1: 241 return ret; 242} 243 244static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 245{ 246 struct xt_ct_target_info *info = par->targinfo; 247 struct xt_ct_target_info_v1 info_v1 = { 248 .flags = info->flags, 249 .zone = info->zone, 250 .ct_events = info->ct_events, 251 .exp_events = info->exp_events, 252 }; 253 int ret; 254 255 if (info->flags & ~XT_CT_NOTRACK) 256 return -EINVAL; 257 258 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 259 260 ret = xt_ct_tg_check(par, &info_v1); 261 if (ret < 0) 262 return ret; 263 264 info->ct = info_v1.ct; 265 266 return ret; 267} 268 269static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 270{ 271 struct xt_ct_target_info_v1 *info = par->targinfo; 272 273 if (info->flags & ~XT_CT_NOTRACK) 274 return -EINVAL; 275 276 return xt_ct_tg_check(par, par->targinfo); 277} 278 279static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 280{ 281 struct xt_ct_target_info_v1 *info = par->targinfo; 282 283 if (info->flags & ~XT_CT_MASK) 284 return -EINVAL; 285 286 return xt_ct_tg_check(par, par->targinfo); 287} 288 289static void xt_ct_destroy_timeout(struct nf_conn *ct) 290{ 291#ifdef CONFIG_NF_CONNTRACK_TIMEOUT 292 struct nf_conn_timeout *timeout_ext; 293 typeof(nf_ct_timeout_put_hook) timeout_put; 294 295 rcu_read_lock(); 296 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 297 298 if (timeout_put) { 299 timeout_ext = nf_ct_timeout_find(ct); 300 if (timeout_ext) 301 timeout_put(timeout_ext->timeout); 302 } 303 rcu_read_unlock(); 304#endif 305} 306 307static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 308 struct xt_ct_target_info_v1 *info) 309{ 310 struct nf_conn *ct = info->ct; 311 struct nf_conn_help *help; 312 313 if (ct && !nf_ct_is_untracked(ct)) { 314 help = nfct_help(ct); 315 if (help) 316 module_put(help->helper->me); 317 318 nf_ct_l3proto_module_put(par->family); 319 320 xt_ct_destroy_timeout(ct); 321 nf_ct_put(info->ct); 322 } 323} 324 325static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 326{ 327 struct xt_ct_target_info *info = par->targinfo; 328 struct xt_ct_target_info_v1 info_v1 = { 329 .flags = info->flags, 330 .zone = info->zone, 331 .ct_events = info->ct_events, 332 .exp_events = info->exp_events, 333 .ct = info->ct, 334 }; 335 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 336 337 xt_ct_tg_destroy(par, &info_v1); 338} 339 340static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 341{ 342 xt_ct_tg_destroy(par, par->targinfo); 343} 344 345static struct xt_target xt_ct_tg_reg[] __read_mostly = { 346 { 347 .name = "CT", 348 .family = NFPROTO_UNSPEC, 349 .targetsize = sizeof(struct xt_ct_target_info), 350 .checkentry = xt_ct_tg_check_v0, 351 .destroy = xt_ct_tg_destroy_v0, 352 .target = xt_ct_target_v0, 353 .table = "raw", 354 .me = THIS_MODULE, 355 }, 356 { 357 .name = "CT", 358 .family = NFPROTO_UNSPEC, 359 .revision = 1, 360 .targetsize = sizeof(struct xt_ct_target_info_v1), 361 .checkentry = xt_ct_tg_check_v1, 362 .destroy = xt_ct_tg_destroy_v1, 363 .target = xt_ct_target_v1, 364 .table = "raw", 365 .me = THIS_MODULE, 366 }, 367 { 368 .name = "CT", 369 .family = NFPROTO_UNSPEC, 370 .revision = 2, 371 .targetsize = sizeof(struct xt_ct_target_info_v1), 372 .checkentry = xt_ct_tg_check_v2, 373 .destroy = xt_ct_tg_destroy_v1, 374 .target = xt_ct_target_v1, 375 .table = "raw", 376 .me = THIS_MODULE, 377 }, 378}; 379 380static unsigned int 381notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 382{ 383 /* Previously seen (loopback)? Ignore. */ 384 if (skb->nfct != NULL) 385 return XT_CONTINUE; 386 387 skb->nfct = &nf_ct_untracked_get()->ct_general; 388 skb->nfctinfo = IP_CT_NEW; 389 nf_conntrack_get(skb->nfct); 390 391 return XT_CONTINUE; 392} 393 394static int notrack_chk(const struct xt_tgchk_param *par) 395{ 396 if (!par->net->xt.notrack_deprecated_warning) { 397 pr_info("netfilter: NOTRACK target is deprecated, " 398 "use CT instead or upgrade iptables\n"); 399 par->net->xt.notrack_deprecated_warning = true; 400 } 401 return 0; 402} 403 404static struct xt_target notrack_tg_reg __read_mostly = { 405 .name = "NOTRACK", 406 .revision = 0, 407 .family = NFPROTO_UNSPEC, 408 .checkentry = notrack_chk, 409 .target = notrack_tg, 410 .table = "raw", 411 .me = THIS_MODULE, 412}; 413 414static int __init xt_ct_tg_init(void) 415{ 416 int ret; 417 418 ret = xt_register_target(¬rack_tg_reg); 419 if (ret < 0) 420 return ret; 421 422 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 423 if (ret < 0) { 424 xt_unregister_target(¬rack_tg_reg); 425 return ret; 426 } 427 return 0; 428} 429 430static void __exit xt_ct_tg_exit(void) 431{ 432 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 433 xt_unregister_target(¬rack_tg_reg); 434} 435 436module_init(xt_ct_tg_init); 437module_exit(xt_ct_tg_exit); 438 439MODULE_LICENSE("GPL"); 440MODULE_DESCRIPTION("Xtables: connection tracking target"); 441MODULE_ALIAS("ipt_CT"); 442MODULE_ALIAS("ip6t_CT"); 443MODULE_ALIAS("ipt_NOTRACK"); 444MODULE_ALIAS("ip6t_NOTRACK"); 445