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