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