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 struct tcf_proto *tp) 102 { 103 struct tc_action_net *tn = net_generic(net, id); 104 struct nlattr *tb[TCA_IPT_MAX + 1]; 105 struct tcf_ipt *ipt; 106 struct xt_entry_target *td, *t; 107 char *tname; 108 bool exists = false; 109 int ret = 0, err; 110 u32 hook = 0; 111 u32 index = 0; 112 113 if (nla == NULL) 114 return -EINVAL; 115 116 err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy, 117 NULL); 118 if (err < 0) 119 return err; 120 121 if (tb[TCA_IPT_INDEX] != NULL) 122 index = nla_get_u32(tb[TCA_IPT_INDEX]); 123 124 err = tcf_idr_check_alloc(tn, &index, a, bind); 125 if (err < 0) 126 return err; 127 exists = err; 128 if (exists && bind) 129 return 0; 130 131 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 132 if (exists) 133 tcf_idr_release(*a, bind); 134 else 135 tcf_idr_cleanup(tn, index); 136 return -EINVAL; 137 } 138 139 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 140 if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) { 141 if (exists) 142 tcf_idr_release(*a, bind); 143 else 144 tcf_idr_cleanup(tn, index); 145 return -EINVAL; 146 } 147 148 if (!exists) { 149 ret = tcf_idr_create(tn, index, est, a, ops, bind, 150 false); 151 if (ret) { 152 tcf_idr_cleanup(tn, index); 153 return ret; 154 } 155 ret = ACT_P_CREATED; 156 } else { 157 if (bind)/* dont override defaults */ 158 return 0; 159 160 if (!ovr) { 161 tcf_idr_release(*a, bind); 162 return -EEXIST; 163 } 164 } 165 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 166 167 err = -ENOMEM; 168 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 169 if (unlikely(!tname)) 170 goto err1; 171 if (tb[TCA_IPT_TABLE] == NULL || 172 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 173 strcpy(tname, "mangle"); 174 175 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 176 if (unlikely(!t)) 177 goto err2; 178 179 err = ipt_init_target(net, t, tname, hook); 180 if (err < 0) 181 goto err3; 182 183 ipt = to_ipt(*a); 184 185 spin_lock_bh(&ipt->tcf_lock); 186 if (ret != ACT_P_CREATED) { 187 ipt_destroy_target(ipt->tcfi_t); 188 kfree(ipt->tcfi_tname); 189 kfree(ipt->tcfi_t); 190 } 191 ipt->tcfi_tname = tname; 192 ipt->tcfi_t = t; 193 ipt->tcfi_hook = hook; 194 spin_unlock_bh(&ipt->tcf_lock); 195 if (ret == ACT_P_CREATED) 196 tcf_idr_insert(tn, *a); 197 return ret; 198 199 err3: 200 kfree(t); 201 err2: 202 kfree(tname); 203 err1: 204 tcf_idr_release(*a, bind); 205 return err; 206 } 207 208 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 209 struct nlattr *est, struct tc_action **a, int ovr, 210 int bind, bool rtnl_held, struct tcf_proto *tp, 211 struct netlink_ext_ack *extack) 212 { 213 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, 214 bind, tp); 215 } 216 217 static int tcf_xt_init(struct net *net, struct nlattr *nla, 218 struct nlattr *est, struct tc_action **a, int ovr, 219 int bind, bool unlocked, struct tcf_proto *tp, 220 struct netlink_ext_ack *extack) 221 { 222 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, 223 bind, tp); 224 } 225 226 static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a, 227 struct tcf_result *res) 228 { 229 int ret = 0, result = 0; 230 struct tcf_ipt *ipt = to_ipt(a); 231 struct xt_action_param par; 232 struct nf_hook_state state = { 233 .net = dev_net(skb->dev), 234 .in = skb->dev, 235 .hook = ipt->tcfi_hook, 236 .pf = NFPROTO_IPV4, 237 }; 238 239 if (skb_unclone(skb, GFP_ATOMIC)) 240 return TC_ACT_UNSPEC; 241 242 spin_lock(&ipt->tcf_lock); 243 244 tcf_lastuse_update(&ipt->tcf_tm); 245 bstats_update(&ipt->tcf_bstats, skb); 246 247 /* yes, we have to worry about both in and out dev 248 * worry later - danger - this API seems to have changed 249 * from earlier kernels 250 */ 251 par.state = &state; 252 par.target = ipt->tcfi_t->u.kernel.target; 253 par.targinfo = ipt->tcfi_t->data; 254 ret = par.target->target(skb, &par); 255 256 switch (ret) { 257 case NF_ACCEPT: 258 result = TC_ACT_OK; 259 break; 260 case NF_DROP: 261 result = TC_ACT_SHOT; 262 ipt->tcf_qstats.drops++; 263 break; 264 case XT_CONTINUE: 265 result = TC_ACT_PIPE; 266 break; 267 default: 268 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 269 ret); 270 result = TC_ACT_OK; 271 break; 272 } 273 spin_unlock(&ipt->tcf_lock); 274 return result; 275 276 } 277 278 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 279 int ref) 280 { 281 unsigned char *b = skb_tail_pointer(skb); 282 struct tcf_ipt *ipt = to_ipt(a); 283 struct xt_entry_target *t; 284 struct tcf_t tm; 285 struct tc_cnt c; 286 287 /* for simple targets kernel size == user size 288 * user name = target name 289 * for foolproof you need to not assume this 290 */ 291 292 spin_lock_bh(&ipt->tcf_lock); 293 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 294 if (unlikely(!t)) 295 goto nla_put_failure; 296 297 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 298 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 299 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 300 301 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 302 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 303 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 304 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 305 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 306 goto nla_put_failure; 307 308 tcf_tm_dump(&tm, &ipt->tcf_tm); 309 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 310 goto nla_put_failure; 311 312 spin_unlock_bh(&ipt->tcf_lock); 313 kfree(t); 314 return skb->len; 315 316 nla_put_failure: 317 spin_unlock_bh(&ipt->tcf_lock); 318 nlmsg_trim(skb, b); 319 kfree(t); 320 return -1; 321 } 322 323 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 324 struct netlink_callback *cb, int type, 325 const struct tc_action_ops *ops, 326 struct netlink_ext_ack *extack) 327 { 328 struct tc_action_net *tn = net_generic(net, ipt_net_id); 329 330 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 331 } 332 333 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) 334 { 335 struct tc_action_net *tn = net_generic(net, ipt_net_id); 336 337 return tcf_idr_search(tn, a, index); 338 } 339 340 static struct tc_action_ops act_ipt_ops = { 341 .kind = "ipt", 342 .id = TCA_ID_IPT, 343 .owner = THIS_MODULE, 344 .act = tcf_ipt_act, 345 .dump = tcf_ipt_dump, 346 .cleanup = tcf_ipt_release, 347 .init = tcf_ipt_init, 348 .walk = tcf_ipt_walker, 349 .lookup = tcf_ipt_search, 350 .size = sizeof(struct tcf_ipt), 351 }; 352 353 static __net_init int ipt_init_net(struct net *net) 354 { 355 struct tc_action_net *tn = net_generic(net, ipt_net_id); 356 357 return tc_action_net_init(tn, &act_ipt_ops); 358 } 359 360 static void __net_exit ipt_exit_net(struct list_head *net_list) 361 { 362 tc_action_net_exit(net_list, ipt_net_id); 363 } 364 365 static struct pernet_operations ipt_net_ops = { 366 .init = ipt_init_net, 367 .exit_batch = ipt_exit_net, 368 .id = &ipt_net_id, 369 .size = sizeof(struct tc_action_net), 370 }; 371 372 static int tcf_xt_walker(struct net *net, struct sk_buff *skb, 373 struct netlink_callback *cb, int type, 374 const struct tc_action_ops *ops, 375 struct netlink_ext_ack *extack) 376 { 377 struct tc_action_net *tn = net_generic(net, xt_net_id); 378 379 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 380 } 381 382 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index) 383 { 384 struct tc_action_net *tn = net_generic(net, xt_net_id); 385 386 return tcf_idr_search(tn, a, index); 387 } 388 389 static struct tc_action_ops act_xt_ops = { 390 .kind = "xt", 391 .id = TCA_ID_XT, 392 .owner = THIS_MODULE, 393 .act = tcf_ipt_act, 394 .dump = tcf_ipt_dump, 395 .cleanup = tcf_ipt_release, 396 .init = tcf_xt_init, 397 .walk = tcf_xt_walker, 398 .lookup = tcf_xt_search, 399 .size = sizeof(struct tcf_ipt), 400 }; 401 402 static __net_init int xt_init_net(struct net *net) 403 { 404 struct tc_action_net *tn = net_generic(net, xt_net_id); 405 406 return tc_action_net_init(tn, &act_xt_ops); 407 } 408 409 static void __net_exit xt_exit_net(struct list_head *net_list) 410 { 411 tc_action_net_exit(net_list, xt_net_id); 412 } 413 414 static struct pernet_operations xt_net_ops = { 415 .init = xt_init_net, 416 .exit_batch = xt_exit_net, 417 .id = &xt_net_id, 418 .size = sizeof(struct tc_action_net), 419 }; 420 421 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 422 MODULE_DESCRIPTION("Iptables target actions"); 423 MODULE_LICENSE("GPL"); 424 MODULE_ALIAS("act_xt"); 425 426 static int __init ipt_init_module(void) 427 { 428 int ret1, ret2; 429 430 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 431 if (ret1 < 0) 432 pr_err("Failed to load xt action\n"); 433 434 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 435 if (ret2 < 0) 436 pr_err("Failed to load ipt action\n"); 437 438 if (ret1 < 0 && ret2 < 0) { 439 return ret1; 440 } else 441 return 0; 442 } 443 444 static void __exit ipt_cleanup_module(void) 445 { 446 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 447 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 448 } 449 450 module_init(ipt_init_module); 451 module_exit(ipt_cleanup_module); 452