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