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 ipt_destroy_target(ipt->tcfi_t); 84 kfree(ipt->tcfi_tname); 85 kfree(ipt->tcfi_t); 86 } 87 88 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 89 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 90 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 91 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 92 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, 93 }; 94 95 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla, 96 struct nlattr *est, struct tc_action **a, 97 const struct tc_action_ops *ops, int ovr, int bind) 98 { 99 struct tc_action_net *tn = net_generic(net, id); 100 struct nlattr *tb[TCA_IPT_MAX + 1]; 101 struct tcf_ipt *ipt; 102 struct xt_entry_target *td, *t; 103 char *tname; 104 bool exists = false; 105 int ret = 0, err; 106 u32 hook = 0; 107 u32 index = 0; 108 109 if (nla == NULL) 110 return -EINVAL; 111 112 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL); 113 if (err < 0) 114 return err; 115 116 if (tb[TCA_IPT_INDEX] != NULL) 117 index = nla_get_u32(tb[TCA_IPT_INDEX]); 118 119 exists = tcf_idr_check(tn, index, a, bind); 120 if (exists && bind) 121 return 0; 122 123 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 124 if (exists) 125 tcf_idr_release(*a, bind); 126 return -EINVAL; 127 } 128 129 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 130 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) { 131 if (exists) 132 tcf_idr_release(*a, bind); 133 return -EINVAL; 134 } 135 136 if (!exists) { 137 ret = tcf_idr_create(tn, index, est, a, ops, bind, 138 false); 139 if (ret) 140 return ret; 141 ret = ACT_P_CREATED; 142 } else { 143 if (bind)/* dont override defaults */ 144 return 0; 145 tcf_idr_release(*a, bind); 146 147 if (!ovr) 148 return -EEXIST; 149 } 150 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 151 152 err = -ENOMEM; 153 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 154 if (unlikely(!tname)) 155 goto err1; 156 if (tb[TCA_IPT_TABLE] == NULL || 157 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 158 strcpy(tname, "mangle"); 159 160 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 161 if (unlikely(!t)) 162 goto err2; 163 164 err = ipt_init_target(net, t, tname, hook); 165 if (err < 0) 166 goto err3; 167 168 ipt = to_ipt(*a); 169 170 spin_lock_bh(&ipt->tcf_lock); 171 if (ret != ACT_P_CREATED) { 172 ipt_destroy_target(ipt->tcfi_t); 173 kfree(ipt->tcfi_tname); 174 kfree(ipt->tcfi_t); 175 } 176 ipt->tcfi_tname = tname; 177 ipt->tcfi_t = t; 178 ipt->tcfi_hook = hook; 179 spin_unlock_bh(&ipt->tcf_lock); 180 if (ret == ACT_P_CREATED) 181 tcf_idr_insert(tn, *a); 182 return ret; 183 184 err3: 185 kfree(t); 186 err2: 187 kfree(tname); 188 err1: 189 if (ret == ACT_P_CREATED) 190 tcf_idr_cleanup(*a, est); 191 return err; 192 } 193 194 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 195 struct nlattr *est, struct tc_action **a, int ovr, 196 int bind) 197 { 198 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, 199 bind); 200 } 201 202 static int tcf_xt_init(struct net *net, struct nlattr *nla, 203 struct nlattr *est, struct tc_action **a, int ovr, 204 int bind) 205 { 206 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, 207 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 struct nf_hook_state state = { 217 .net = dev_net(skb->dev), 218 .in = skb->dev, 219 .hook = ipt->tcfi_hook, 220 .pf = NFPROTO_IPV4, 221 }; 222 223 if (skb_unclone(skb, GFP_ATOMIC)) 224 return TC_ACT_UNSPEC; 225 226 spin_lock(&ipt->tcf_lock); 227 228 tcf_lastuse_update(&ipt->tcf_tm); 229 bstats_update(&ipt->tcf_bstats, skb); 230 231 /* yes, we have to worry about both in and out dev 232 * worry later - danger - this API seems to have changed 233 * from earlier kernels 234 */ 235 par.state = &state; 236 par.target = ipt->tcfi_t->u.kernel.target; 237 par.targinfo = ipt->tcfi_t->data; 238 ret = par.target->target(skb, &par); 239 240 switch (ret) { 241 case NF_ACCEPT: 242 result = TC_ACT_OK; 243 break; 244 case NF_DROP: 245 result = TC_ACT_SHOT; 246 ipt->tcf_qstats.drops++; 247 break; 248 case XT_CONTINUE: 249 result = TC_ACT_PIPE; 250 break; 251 default: 252 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 253 ret); 254 result = TC_ACT_OK; 255 break; 256 } 257 spin_unlock(&ipt->tcf_lock); 258 return result; 259 260 } 261 262 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 263 int ref) 264 { 265 unsigned char *b = skb_tail_pointer(skb); 266 struct tcf_ipt *ipt = to_ipt(a); 267 struct xt_entry_target *t; 268 struct tcf_t tm; 269 struct tc_cnt c; 270 271 /* for simple targets kernel size == user size 272 * user name = target name 273 * for foolproof you need to not assume this 274 */ 275 276 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 277 if (unlikely(!t)) 278 goto nla_put_failure; 279 280 c.bindcnt = ipt->tcf_bindcnt - bind; 281 c.refcnt = ipt->tcf_refcnt - ref; 282 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 283 284 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 285 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 286 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 287 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 288 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 289 goto nla_put_failure; 290 291 tcf_tm_dump(&tm, &ipt->tcf_tm); 292 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 293 goto nla_put_failure; 294 295 kfree(t); 296 return skb->len; 297 298 nla_put_failure: 299 nlmsg_trim(skb, b); 300 kfree(t); 301 return -1; 302 } 303 304 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 305 struct netlink_callback *cb, int type, 306 const struct tc_action_ops *ops) 307 { 308 struct tc_action_net *tn = net_generic(net, ipt_net_id); 309 310 return tcf_generic_walker(tn, skb, cb, type, ops); 311 } 312 313 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) 314 { 315 struct tc_action_net *tn = net_generic(net, ipt_net_id); 316 317 return tcf_idr_search(tn, a, index); 318 } 319 320 static struct tc_action_ops act_ipt_ops = { 321 .kind = "ipt", 322 .type = TCA_ACT_IPT, 323 .owner = THIS_MODULE, 324 .act = tcf_ipt, 325 .dump = tcf_ipt_dump, 326 .cleanup = tcf_ipt_release, 327 .init = tcf_ipt_init, 328 .walk = tcf_ipt_walker, 329 .lookup = tcf_ipt_search, 330 .size = sizeof(struct tcf_ipt), 331 }; 332 333 static __net_init int ipt_init_net(struct net *net) 334 { 335 struct tc_action_net *tn = net_generic(net, ipt_net_id); 336 337 return tc_action_net_init(tn, &act_ipt_ops); 338 } 339 340 static void __net_exit ipt_exit_net(struct list_head *net_list) 341 { 342 tc_action_net_exit(net_list, ipt_net_id); 343 } 344 345 static struct pernet_operations ipt_net_ops = { 346 .init = ipt_init_net, 347 .exit_batch = 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_idr_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); 386 } 387 388 static void __net_exit xt_exit_net(struct list_head *net_list) 389 { 390 tc_action_net_exit(net_list, xt_net_id); 391 } 392 393 static struct pernet_operations xt_net_ops = { 394 .init = xt_init_net, 395 .exit_batch = xt_exit_net, 396 .id = &xt_net_id, 397 .size = sizeof(struct tc_action_net), 398 }; 399 400 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 401 MODULE_DESCRIPTION("Iptables target actions"); 402 MODULE_LICENSE("GPL"); 403 MODULE_ALIAS("act_xt"); 404 405 static int __init ipt_init_module(void) 406 { 407 int ret1, ret2; 408 409 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 410 if (ret1 < 0) 411 pr_err("Failed to load xt action\n"); 412 413 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 414 if (ret2 < 0) 415 pr_err("Failed to load ipt action\n"); 416 417 if (ret1 < 0 && ret2 < 0) { 418 return ret1; 419 } else 420 return 0; 421 } 422 423 static void __exit ipt_cleanup_module(void) 424 { 425 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 426 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 427 } 428 429 module_init(ipt_init_module); 430 module_exit(ipt_cleanup_module); 431