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