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 err = tcf_idr_check_alloc(tn, &index, a, bind); 123 if (err < 0) 124 return err; 125 exists = err; 126 if (exists && bind) 127 return 0; 128 129 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 130 if (exists) 131 tcf_idr_release(*a, bind); 132 else 133 tcf_idr_cleanup(tn, index); 134 return -EINVAL; 135 } 136 137 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 138 if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) { 139 if (exists) 140 tcf_idr_release(*a, bind); 141 else 142 tcf_idr_cleanup(tn, index); 143 return -EINVAL; 144 } 145 146 if (!exists) { 147 ret = tcf_idr_create(tn, index, est, a, ops, bind, 148 false); 149 if (ret) { 150 tcf_idr_cleanup(tn, index); 151 return ret; 152 } 153 ret = ACT_P_CREATED; 154 } else { 155 if (bind)/* dont override defaults */ 156 return 0; 157 158 if (!ovr) { 159 tcf_idr_release(*a, bind); 160 return -EEXIST; 161 } 162 } 163 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 164 165 err = -ENOMEM; 166 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 167 if (unlikely(!tname)) 168 goto err1; 169 if (tb[TCA_IPT_TABLE] == NULL || 170 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 171 strcpy(tname, "mangle"); 172 173 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 174 if (unlikely(!t)) 175 goto err2; 176 177 err = ipt_init_target(net, t, tname, hook); 178 if (err < 0) 179 goto err3; 180 181 ipt = to_ipt(*a); 182 183 spin_lock_bh(&ipt->tcf_lock); 184 if (ret != ACT_P_CREATED) { 185 ipt_destroy_target(ipt->tcfi_t); 186 kfree(ipt->tcfi_tname); 187 kfree(ipt->tcfi_t); 188 } 189 ipt->tcfi_tname = tname; 190 ipt->tcfi_t = t; 191 ipt->tcfi_hook = hook; 192 spin_unlock_bh(&ipt->tcf_lock); 193 if (ret == ACT_P_CREATED) 194 tcf_idr_insert(tn, *a); 195 return ret; 196 197 err3: 198 kfree(t); 199 err2: 200 kfree(tname); 201 err1: 202 tcf_idr_release(*a, bind); 203 return err; 204 } 205 206 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 207 struct nlattr *est, struct tc_action **a, int ovr, 208 int bind, bool rtnl_held, 209 struct netlink_ext_ack *extack) 210 { 211 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, 212 bind); 213 } 214 215 static int tcf_xt_init(struct net *net, struct nlattr *nla, 216 struct nlattr *est, struct tc_action **a, int ovr, 217 int bind, bool unlocked, 218 struct netlink_ext_ack *extack) 219 { 220 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, 221 bind); 222 } 223 224 static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a, 225 struct tcf_result *res) 226 { 227 int ret = 0, result = 0; 228 struct tcf_ipt *ipt = to_ipt(a); 229 struct xt_action_param par; 230 struct nf_hook_state state = { 231 .net = dev_net(skb->dev), 232 .in = skb->dev, 233 .hook = ipt->tcfi_hook, 234 .pf = NFPROTO_IPV4, 235 }; 236 237 if (skb_unclone(skb, GFP_ATOMIC)) 238 return TC_ACT_UNSPEC; 239 240 spin_lock(&ipt->tcf_lock); 241 242 tcf_lastuse_update(&ipt->tcf_tm); 243 bstats_update(&ipt->tcf_bstats, skb); 244 245 /* yes, we have to worry about both in and out dev 246 * worry later - danger - this API seems to have changed 247 * from earlier kernels 248 */ 249 par.state = &state; 250 par.target = ipt->tcfi_t->u.kernel.target; 251 par.targinfo = ipt->tcfi_t->data; 252 ret = par.target->target(skb, &par); 253 254 switch (ret) { 255 case NF_ACCEPT: 256 result = TC_ACT_OK; 257 break; 258 case NF_DROP: 259 result = TC_ACT_SHOT; 260 ipt->tcf_qstats.drops++; 261 break; 262 case XT_CONTINUE: 263 result = TC_ACT_PIPE; 264 break; 265 default: 266 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 267 ret); 268 result = TC_ACT_OK; 269 break; 270 } 271 spin_unlock(&ipt->tcf_lock); 272 return result; 273 274 } 275 276 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 277 int ref) 278 { 279 unsigned char *b = skb_tail_pointer(skb); 280 struct tcf_ipt *ipt = to_ipt(a); 281 struct xt_entry_target *t; 282 struct tcf_t tm; 283 struct tc_cnt c; 284 285 /* for simple targets kernel size == user size 286 * user name = target name 287 * for foolproof you need to not assume this 288 */ 289 290 spin_lock_bh(&ipt->tcf_lock); 291 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 292 if (unlikely(!t)) 293 goto nla_put_failure; 294 295 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 296 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 297 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 298 299 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 300 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 301 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 302 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 303 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 304 goto nla_put_failure; 305 306 tcf_tm_dump(&tm, &ipt->tcf_tm); 307 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 308 goto nla_put_failure; 309 310 spin_unlock_bh(&ipt->tcf_lock); 311 kfree(t); 312 return skb->len; 313 314 nla_put_failure: 315 spin_unlock_bh(&ipt->tcf_lock); 316 nlmsg_trim(skb, b); 317 kfree(t); 318 return -1; 319 } 320 321 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 322 struct netlink_callback *cb, int type, 323 const struct tc_action_ops *ops, 324 struct netlink_ext_ack *extack) 325 { 326 struct tc_action_net *tn = net_generic(net, ipt_net_id); 327 328 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 329 } 330 331 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) 332 { 333 struct tc_action_net *tn = net_generic(net, ipt_net_id); 334 335 return tcf_idr_search(tn, a, index); 336 } 337 338 static struct tc_action_ops act_ipt_ops = { 339 .kind = "ipt", 340 .id = TCA_ID_IPT, 341 .owner = THIS_MODULE, 342 .act = tcf_ipt_act, 343 .dump = tcf_ipt_dump, 344 .cleanup = tcf_ipt_release, 345 .init = tcf_ipt_init, 346 .walk = tcf_ipt_walker, 347 .lookup = tcf_ipt_search, 348 .size = sizeof(struct tcf_ipt), 349 }; 350 351 static __net_init int ipt_init_net(struct net *net) 352 { 353 struct tc_action_net *tn = net_generic(net, ipt_net_id); 354 355 return tc_action_net_init(tn, &act_ipt_ops); 356 } 357 358 static void __net_exit ipt_exit_net(struct list_head *net_list) 359 { 360 tc_action_net_exit(net_list, ipt_net_id); 361 } 362 363 static struct pernet_operations ipt_net_ops = { 364 .init = ipt_init_net, 365 .exit_batch = ipt_exit_net, 366 .id = &ipt_net_id, 367 .size = sizeof(struct tc_action_net), 368 }; 369 370 static int tcf_xt_walker(struct net *net, struct sk_buff *skb, 371 struct netlink_callback *cb, int type, 372 const struct tc_action_ops *ops, 373 struct netlink_ext_ack *extack) 374 { 375 struct tc_action_net *tn = net_generic(net, xt_net_id); 376 377 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 378 } 379 380 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index) 381 { 382 struct tc_action_net *tn = net_generic(net, xt_net_id); 383 384 return tcf_idr_search(tn, a, index); 385 } 386 387 static struct tc_action_ops act_xt_ops = { 388 .kind = "xt", 389 .id = TCA_ID_XT, 390 .owner = THIS_MODULE, 391 .act = tcf_ipt_act, 392 .dump = tcf_ipt_dump, 393 .cleanup = tcf_ipt_release, 394 .init = tcf_xt_init, 395 .walk = tcf_xt_walker, 396 .lookup = tcf_xt_search, 397 .size = sizeof(struct tcf_ipt), 398 }; 399 400 static __net_init int xt_init_net(struct net *net) 401 { 402 struct tc_action_net *tn = net_generic(net, xt_net_id); 403 404 return tc_action_net_init(tn, &act_xt_ops); 405 } 406 407 static void __net_exit xt_exit_net(struct list_head *net_list) 408 { 409 tc_action_net_exit(net_list, xt_net_id); 410 } 411 412 static struct pernet_operations xt_net_ops = { 413 .init = xt_init_net, 414 .exit_batch = xt_exit_net, 415 .id = &xt_net_id, 416 .size = sizeof(struct tc_action_net), 417 }; 418 419 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 420 MODULE_DESCRIPTION("Iptables target actions"); 421 MODULE_LICENSE("GPL"); 422 MODULE_ALIAS("act_xt"); 423 424 static int __init ipt_init_module(void) 425 { 426 int ret1, ret2; 427 428 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 429 if (ret1 < 0) 430 pr_err("Failed to load xt action\n"); 431 432 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 433 if (ret2 < 0) 434 pr_err("Failed to load ipt action\n"); 435 436 if (ret1 < 0 && ret2 < 0) { 437 return ret1; 438 } else 439 return 0; 440 } 441 442 static void __exit ipt_cleanup_module(void) 443 { 444 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 445 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 446 } 447 448 module_init(ipt_init_module); 449 module_exit(ipt_cleanup_module); 450