1 /* 2 * net/sched/act_ipt.c iptables target interface 3 * 4 *TODO: Add other tables. For now we only support the ipv4 table targets 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * Copyright: Jamal Hadi Salim (2002-13) 12 */ 13 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/string.h> 17 #include <linux/errno.h> 18 #include <linux/skbuff.h> 19 #include <linux/rtnetlink.h> 20 #include <linux/module.h> 21 #include <linux/init.h> 22 #include <linux/slab.h> 23 #include <net/netlink.h> 24 #include <net/pkt_sched.h> 25 #include <linux/tc_act/tc_ipt.h> 26 #include <net/tc_act/tc_ipt.h> 27 28 #include <linux/netfilter_ipv4/ip_tables.h> 29 30 31 static unsigned int ipt_net_id; 32 static struct tc_action_ops act_ipt_ops; 33 34 static unsigned int xt_net_id; 35 static struct tc_action_ops act_xt_ops; 36 37 static int ipt_init_target(struct net *net, struct xt_entry_target *t, 38 char *table, unsigned int hook) 39 { 40 struct xt_tgchk_param par; 41 struct xt_target *target; 42 struct ipt_entry e = {}; 43 int ret = 0; 44 45 target = xt_request_find_target(AF_INET, t->u.user.name, 46 t->u.user.revision); 47 if (IS_ERR(target)) 48 return PTR_ERR(target); 49 50 t->u.kernel.target = target; 51 memset(&par, 0, sizeof(par)); 52 par.net = net; 53 par.table = table; 54 par.entryinfo = &e; 55 par.target = target; 56 par.targinfo = t->data; 57 par.hook_mask = hook; 58 par.family = NFPROTO_IPV4; 59 60 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 61 if (ret < 0) { 62 module_put(t->u.kernel.target->me); 63 return ret; 64 } 65 return 0; 66 } 67 68 static void ipt_destroy_target(struct xt_entry_target *t) 69 { 70 struct xt_tgdtor_param par = { 71 .target = t->u.kernel.target, 72 .targinfo = t->data, 73 .family = NFPROTO_IPV4, 74 }; 75 if (par.target->destroy != NULL) 76 par.target->destroy(&par); 77 module_put(par.target->me); 78 } 79 80 static void tcf_ipt_release(struct tc_action *a) 81 { 82 struct tcf_ipt *ipt = to_ipt(a); 83 84 if (ipt->tcfi_t) { 85 ipt_destroy_target(ipt->tcfi_t); 86 kfree(ipt->tcfi_t); 87 } 88 kfree(ipt->tcfi_tname); 89 } 90 91 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 92 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 93 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 94 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 95 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, 96 }; 97 98 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla, 99 struct nlattr *est, struct tc_action **a, 100 const struct tc_action_ops *ops, int ovr, int bind) 101 { 102 struct tc_action_net *tn = net_generic(net, id); 103 struct nlattr *tb[TCA_IPT_MAX + 1]; 104 struct tcf_ipt *ipt; 105 struct xt_entry_target *td, *t; 106 char *tname; 107 bool exists = false; 108 int ret = 0, err; 109 u32 hook = 0; 110 u32 index = 0; 111 112 if (nla == NULL) 113 return -EINVAL; 114 115 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL); 116 if (err < 0) 117 return err; 118 119 if (tb[TCA_IPT_INDEX] != NULL) 120 index = nla_get_u32(tb[TCA_IPT_INDEX]); 121 122 exists = tcf_idr_check(tn, index, a, bind); 123 if (exists && bind) 124 return 0; 125 126 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 127 if (exists) 128 tcf_idr_release(*a, bind); 129 return -EINVAL; 130 } 131 132 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 133 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) { 134 if (exists) 135 tcf_idr_release(*a, bind); 136 return -EINVAL; 137 } 138 139 if (!exists) { 140 ret = tcf_idr_create(tn, index, est, a, ops, bind, 141 false); 142 if (ret) 143 return ret; 144 ret = ACT_P_CREATED; 145 } else { 146 if (bind)/* dont override defaults */ 147 return 0; 148 149 if (!ovr) { 150 tcf_idr_release(*a, bind); 151 return -EEXIST; 152 } 153 } 154 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 155 156 err = -ENOMEM; 157 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 158 if (unlikely(!tname)) 159 goto err1; 160 if (tb[TCA_IPT_TABLE] == NULL || 161 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 162 strcpy(tname, "mangle"); 163 164 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 165 if (unlikely(!t)) 166 goto err2; 167 168 err = ipt_init_target(net, t, tname, hook); 169 if (err < 0) 170 goto err3; 171 172 ipt = to_ipt(*a); 173 174 spin_lock_bh(&ipt->tcf_lock); 175 if (ret != ACT_P_CREATED) { 176 ipt_destroy_target(ipt->tcfi_t); 177 kfree(ipt->tcfi_tname); 178 kfree(ipt->tcfi_t); 179 } 180 ipt->tcfi_tname = tname; 181 ipt->tcfi_t = t; 182 ipt->tcfi_hook = hook; 183 spin_unlock_bh(&ipt->tcf_lock); 184 if (ret == ACT_P_CREATED) 185 tcf_idr_insert(tn, *a); 186 return ret; 187 188 err3: 189 kfree(t); 190 err2: 191 kfree(tname); 192 err1: 193 if (ret == ACT_P_CREATED) 194 tcf_idr_release(*a, bind); 195 return err; 196 } 197 198 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 199 struct nlattr *est, struct tc_action **a, int ovr, 200 int bind, bool rtnl_held, 201 struct netlink_ext_ack *extack) 202 { 203 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, 204 bind); 205 } 206 207 static int tcf_xt_init(struct net *net, struct nlattr *nla, 208 struct nlattr *est, struct tc_action **a, int ovr, 209 int bind, bool unlocked, 210 struct netlink_ext_ack *extack) 211 { 212 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, 213 bind); 214 } 215 216 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a, 217 struct tcf_result *res) 218 { 219 int ret = 0, result = 0; 220 struct tcf_ipt *ipt = to_ipt(a); 221 struct xt_action_param par; 222 struct nf_hook_state state = { 223 .net = dev_net(skb->dev), 224 .in = skb->dev, 225 .hook = ipt->tcfi_hook, 226 .pf = NFPROTO_IPV4, 227 }; 228 229 if (skb_unclone(skb, GFP_ATOMIC)) 230 return TC_ACT_UNSPEC; 231 232 spin_lock(&ipt->tcf_lock); 233 234 tcf_lastuse_update(&ipt->tcf_tm); 235 bstats_update(&ipt->tcf_bstats, skb); 236 237 /* yes, we have to worry about both in and out dev 238 * worry later - danger - this API seems to have changed 239 * from earlier kernels 240 */ 241 par.state = &state; 242 par.target = ipt->tcfi_t->u.kernel.target; 243 par.targinfo = ipt->tcfi_t->data; 244 ret = par.target->target(skb, &par); 245 246 switch (ret) { 247 case NF_ACCEPT: 248 result = TC_ACT_OK; 249 break; 250 case NF_DROP: 251 result = TC_ACT_SHOT; 252 ipt->tcf_qstats.drops++; 253 break; 254 case XT_CONTINUE: 255 result = TC_ACT_PIPE; 256 break; 257 default: 258 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 259 ret); 260 result = TC_ACT_OK; 261 break; 262 } 263 spin_unlock(&ipt->tcf_lock); 264 return result; 265 266 } 267 268 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 269 int ref) 270 { 271 unsigned char *b = skb_tail_pointer(skb); 272 struct tcf_ipt *ipt = to_ipt(a); 273 struct xt_entry_target *t; 274 struct tcf_t tm; 275 struct tc_cnt c; 276 277 /* for simple targets kernel size == user size 278 * user name = target name 279 * for foolproof you need to not assume this 280 */ 281 282 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 283 if (unlikely(!t)) 284 goto nla_put_failure; 285 286 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 287 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 288 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 289 290 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 291 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 292 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 293 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 294 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 295 goto nla_put_failure; 296 297 tcf_tm_dump(&tm, &ipt->tcf_tm); 298 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 299 goto nla_put_failure; 300 301 kfree(t); 302 return skb->len; 303 304 nla_put_failure: 305 nlmsg_trim(skb, b); 306 kfree(t); 307 return -1; 308 } 309 310 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 311 struct netlink_callback *cb, int type, 312 const struct tc_action_ops *ops, 313 struct netlink_ext_ack *extack) 314 { 315 struct tc_action_net *tn = net_generic(net, ipt_net_id); 316 317 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 318 } 319 320 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index, 321 struct netlink_ext_ack *extack) 322 { 323 struct tc_action_net *tn = net_generic(net, ipt_net_id); 324 325 return tcf_idr_search(tn, a, index); 326 } 327 328 static int tcf_ipt_delete(struct net *net, u32 index) 329 { 330 struct tc_action_net *tn = net_generic(net, ipt_net_id); 331 332 return tcf_idr_delete_index(tn, index); 333 } 334 335 static struct tc_action_ops act_ipt_ops = { 336 .kind = "ipt", 337 .type = TCA_ACT_IPT, 338 .owner = THIS_MODULE, 339 .act = tcf_ipt, 340 .dump = tcf_ipt_dump, 341 .cleanup = tcf_ipt_release, 342 .init = tcf_ipt_init, 343 .walk = tcf_ipt_walker, 344 .lookup = tcf_ipt_search, 345 .delete = tcf_ipt_delete, 346 .size = sizeof(struct tcf_ipt), 347 }; 348 349 static __net_init int ipt_init_net(struct net *net) 350 { 351 struct tc_action_net *tn = net_generic(net, ipt_net_id); 352 353 return tc_action_net_init(tn, &act_ipt_ops); 354 } 355 356 static void __net_exit ipt_exit_net(struct list_head *net_list) 357 { 358 tc_action_net_exit(net_list, ipt_net_id); 359 } 360 361 static struct pernet_operations ipt_net_ops = { 362 .init = ipt_init_net, 363 .exit_batch = ipt_exit_net, 364 .id = &ipt_net_id, 365 .size = sizeof(struct tc_action_net), 366 }; 367 368 static int tcf_xt_walker(struct net *net, struct sk_buff *skb, 369 struct netlink_callback *cb, int type, 370 const struct tc_action_ops *ops, 371 struct netlink_ext_ack *extack) 372 { 373 struct tc_action_net *tn = net_generic(net, xt_net_id); 374 375 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 376 } 377 378 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index, 379 struct netlink_ext_ack *extack) 380 { 381 struct tc_action_net *tn = net_generic(net, xt_net_id); 382 383 return tcf_idr_search(tn, a, index); 384 } 385 386 static int tcf_xt_delete(struct net *net, u32 index) 387 { 388 struct tc_action_net *tn = net_generic(net, xt_net_id); 389 390 return tcf_idr_delete_index(tn, index); 391 } 392 393 static struct tc_action_ops act_xt_ops = { 394 .kind = "xt", 395 .type = TCA_ACT_XT, 396 .owner = THIS_MODULE, 397 .act = tcf_ipt, 398 .dump = tcf_ipt_dump, 399 .cleanup = tcf_ipt_release, 400 .init = tcf_xt_init, 401 .walk = tcf_xt_walker, 402 .lookup = tcf_xt_search, 403 .delete = tcf_xt_delete, 404 .size = sizeof(struct tcf_ipt), 405 }; 406 407 static __net_init int xt_init_net(struct net *net) 408 { 409 struct tc_action_net *tn = net_generic(net, xt_net_id); 410 411 return tc_action_net_init(tn, &act_xt_ops); 412 } 413 414 static void __net_exit xt_exit_net(struct list_head *net_list) 415 { 416 tc_action_net_exit(net_list, xt_net_id); 417 } 418 419 static struct pernet_operations xt_net_ops = { 420 .init = xt_init_net, 421 .exit_batch = xt_exit_net, 422 .id = &xt_net_id, 423 .size = sizeof(struct tc_action_net), 424 }; 425 426 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 427 MODULE_DESCRIPTION("Iptables target actions"); 428 MODULE_LICENSE("GPL"); 429 MODULE_ALIAS("act_xt"); 430 431 static int __init ipt_init_module(void) 432 { 433 int ret1, ret2; 434 435 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 436 if (ret1 < 0) 437 pr_err("Failed to load xt action\n"); 438 439 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 440 if (ret2 < 0) 441 pr_err("Failed to load ipt action\n"); 442 443 if (ret1 < 0 && ret2 < 0) { 444 return ret1; 445 } else 446 return 0; 447 } 448 449 static void __exit ipt_cleanup_module(void) 450 { 451 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 452 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 453 } 454 455 module_init(ipt_init_module); 456 module_exit(ipt_cleanup_module); 457