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