net/sched/act_ipt.c

   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
  84         if (ipt->tcfi_t) {
  85                 ipt_destroy_target(ipt->tcfi_t);
  86                 kfree(ipt->tcfi_t);
  87         }
  88         kfree(ipt->tcfi_tname);
  89 }
  90
  91 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  92         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  93         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  94         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  95         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  96 };
  97
  98 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
  99                           struct nlattr *est, struct tc_action **a,
 100                           const struct tc_action_ops *ops, int ovr, int bind,
 101                           struct tcf_proto *tp)
 102 {
 103         struct tc_action_net *tn = net_generic(net, id);
 104         struct nlattr *tb[TCA_IPT_MAX + 1];
 105         struct tcf_ipt *ipt;
 106         struct xt_entry_target *td, *t;
 107         char *tname;
 108         bool exists = false;
 109         int ret = 0, err;
 110         u32 hook = 0;
 111         u32 index = 0;
 112
 113         if (nla == NULL)
 114                 return -EINVAL;
 115
 116         err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy,
 117                                           NULL);
 118         if (err < 0)
 119                 return err;
 120
 121         if (tb[TCA_IPT_INDEX] != NULL)
 122                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 123
 124         err = tcf_idr_check_alloc(tn, &index, a, bind);
 125         if (err < 0)
 126                 return err;
 127         exists = err;
 128         if (exists && bind)
 129                 return 0;
 130
 131         if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 132                 if (exists)
 133                         tcf_idr_release(*a, bind);
 134                 else
 135                         tcf_idr_cleanup(tn, index);
 136                 return -EINVAL;
 137         }
 138
 139         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 140         if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) {
 141                 if (exists)
 142                         tcf_idr_release(*a, bind);
 143                 else
 144                         tcf_idr_cleanup(tn, index);
 145                 return -EINVAL;
 146         }
 147
 148         if (!exists) {
 149                 ret = tcf_idr_create(tn, index, est, a, ops, bind,
 150                                      false);
 151                 if (ret) {
 152                         tcf_idr_cleanup(tn, index);
 153                         return ret;
 154                 }
 155                 ret = ACT_P_CREATED;
 156         } else {
 157                 if (bind)/* dont override defaults */
 158                         return 0;
 159
 160                 if (!ovr) {
 161                         tcf_idr_release(*a, bind);
 162                         return -EEXIST;
 163                 }
 164         }
 165         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 166
 167         err = -ENOMEM;
 168         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 169         if (unlikely(!tname))
 170                 goto err1;
 171         if (tb[TCA_IPT_TABLE] == NULL ||
 172             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 173                 strcpy(tname, "mangle");
 174
 175         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 176         if (unlikely(!t))
 177                 goto err2;
 178
 179         err = ipt_init_target(net, t, tname, hook);
 180         if (err < 0)
 181                 goto err3;
 182
 183         ipt = to_ipt(*a);
 184
 185         spin_lock_bh(&ipt->tcf_lock);
 186         if (ret != ACT_P_CREATED) {
 187                 ipt_destroy_target(ipt->tcfi_t);
 188                 kfree(ipt->tcfi_tname);
 189                 kfree(ipt->tcfi_t);
 190         }
 191         ipt->tcfi_tname = tname;
 192         ipt->tcfi_t     = t;
 193         ipt->tcfi_hook  = hook;
 194         spin_unlock_bh(&ipt->tcf_lock);
 195         if (ret == ACT_P_CREATED)
 196                 tcf_idr_insert(tn, *a);
 197         return ret;
 198
 199 err3:
 200         kfree(t);
 201 err2:
 202         kfree(tname);
 203 err1:
 204         tcf_idr_release(*a, bind);
 205         return err;
 206 }
 207
 208 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 209                         struct nlattr *est, struct tc_action **a, int ovr,
 210                         int bind, bool rtnl_held, struct tcf_proto *tp,
 211                         struct netlink_ext_ack *extack)
 212 {
 213         return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
 214                               bind, tp);
 215 }
 216
 217 static int tcf_xt_init(struct net *net, struct nlattr *nla,
 218                        struct nlattr *est, struct tc_action **a, int ovr,
 219                        int bind, bool unlocked, struct tcf_proto *tp,
 220                        struct netlink_ext_ack *extack)
 221 {
 222         return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
 223                               bind, tp);
 224 }
 225
 226 static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a,
 227                        struct tcf_result *res)
 228 {
 229         int ret = 0, result = 0;
 230         struct tcf_ipt *ipt = to_ipt(a);
 231         struct xt_action_param par;
 232         struct nf_hook_state state = {
 233                 .net    = dev_net(skb->dev),
 234                 .in     = skb->dev,
 235                 .hook   = ipt->tcfi_hook,
 236                 .pf     = NFPROTO_IPV4,
 237         };
 238
 239         if (skb_unclone(skb, GFP_ATOMIC))
 240                 return TC_ACT_UNSPEC;
 241
 242         spin_lock(&ipt->tcf_lock);
 243
 244         tcf_lastuse_update(&ipt->tcf_tm);
 245         bstats_update(&ipt->tcf_bstats, skb);
 246
 247         /* yes, we have to worry about both in and out dev
 248          * worry later - danger - this API seems to have changed
 249          * from earlier kernels
 250          */
 251         par.state    = &state;
 252         par.target   = ipt->tcfi_t->u.kernel.target;
 253         par.targinfo = ipt->tcfi_t->data;
 254         ret = par.target->target(skb, &par);
 255
 256         switch (ret) {
 257         case NF_ACCEPT:
 258                 result = TC_ACT_OK;
 259                 break;
 260         case NF_DROP:
 261                 result = TC_ACT_SHOT;
 262                 ipt->tcf_qstats.drops++;
 263                 break;
 264         case XT_CONTINUE:
 265                 result = TC_ACT_PIPE;
 266                 break;
 267         default:
 268                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 269                                        ret);
 270                 result = TC_ACT_OK;
 271                 break;
 272         }
 273         spin_unlock(&ipt->tcf_lock);
 274         return result;
 275
 276 }
 277
 278 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 279                         int ref)
 280 {
 281         unsigned char *b = skb_tail_pointer(skb);
 282         struct tcf_ipt *ipt = to_ipt(a);
 283         struct xt_entry_target *t;
 284         struct tcf_t tm;
 285         struct tc_cnt c;
 286
 287         /* for simple targets kernel size == user size
 288          * user name = target name
 289          * for foolproof you need to not assume this
 290          */
 291
 292         spin_lock_bh(&ipt->tcf_lock);
 293         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 294         if (unlikely(!t))
 295                 goto nla_put_failure;
 296
 297         c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
 298         c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
 299         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 300
 301         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 302             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 303             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 304             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 305             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 306                 goto nla_put_failure;
 307
 308         tcf_tm_dump(&tm, &ipt->tcf_tm);
 309         if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 310                 goto nla_put_failure;
 311
 312         spin_unlock_bh(&ipt->tcf_lock);
 313         kfree(t);
 314         return skb->len;
 315
 316 nla_put_failure:
 317         spin_unlock_bh(&ipt->tcf_lock);
 318         nlmsg_trim(skb, b);
 319         kfree(t);
 320         return -1;
 321 }
 322
 323 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 324                           struct netlink_callback *cb, int type,
 325                           const struct tc_action_ops *ops,
 326                           struct netlink_ext_ack *extack)
 327 {
 328         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 329
 330         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 331 }
 332
 333 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
 334 {
 335         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 336
 337         return tcf_idr_search(tn, a, index);
 338 }
 339
 340 static struct tc_action_ops act_ipt_ops = {
 341         .kind           =       "ipt",
 342         .id             =       TCA_ID_IPT,
 343         .owner          =       THIS_MODULE,
 344         .act            =       tcf_ipt_act,
 345         .dump           =       tcf_ipt_dump,
 346         .cleanup        =       tcf_ipt_release,
 347         .init           =       tcf_ipt_init,
 348         .walk           =       tcf_ipt_walker,
 349         .lookup         =       tcf_ipt_search,
 350         .size           =       sizeof(struct tcf_ipt),
 351 };
 352
 353 static __net_init int ipt_init_net(struct net *net)
 354 {
 355         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 356
 357         return tc_action_net_init(tn, &act_ipt_ops);
 358 }
 359
 360 static void __net_exit ipt_exit_net(struct list_head *net_list)
 361 {
 362         tc_action_net_exit(net_list, ipt_net_id);
 363 }
 364
 365 static struct pernet_operations ipt_net_ops = {
 366         .init = ipt_init_net,
 367         .exit_batch = ipt_exit_net,
 368         .id   = &ipt_net_id,
 369         .size = sizeof(struct tc_action_net),
 370 };
 371
 372 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
 373                          struct netlink_callback *cb, int type,
 374                          const struct tc_action_ops *ops,
 375                          struct netlink_ext_ack *extack)
 376 {
 377         struct tc_action_net *tn = net_generic(net, xt_net_id);
 378
 379         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 380 }
 381
 382 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
 383 {
 384         struct tc_action_net *tn = net_generic(net, xt_net_id);
 385
 386         return tcf_idr_search(tn, a, index);
 387 }
 388
 389 static struct tc_action_ops act_xt_ops = {
 390         .kind           =       "xt",
 391         .id             =       TCA_ID_XT,
 392         .owner          =       THIS_MODULE,
 393         .act            =       tcf_ipt_act,
 394         .dump           =       tcf_ipt_dump,
 395         .cleanup        =       tcf_ipt_release,
 396         .init           =       tcf_xt_init,
 397         .walk           =       tcf_xt_walker,
 398         .lookup         =       tcf_xt_search,
 399         .size           =       sizeof(struct tcf_ipt),
 400 };
 401
 402 static __net_init int xt_init_net(struct net *net)
 403 {
 404         struct tc_action_net *tn = net_generic(net, xt_net_id);
 405
 406         return tc_action_net_init(tn, &act_xt_ops);
 407 }
 408
 409 static void __net_exit xt_exit_net(struct list_head *net_list)
 410 {
 411         tc_action_net_exit(net_list, xt_net_id);
 412 }
 413
 414 static struct pernet_operations xt_net_ops = {
 415         .init = xt_init_net,
 416         .exit_batch = xt_exit_net,
 417         .id   = &xt_net_id,
 418         .size = sizeof(struct tc_action_net),
 419 };
 420
 421 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 422 MODULE_DESCRIPTION("Iptables target actions");
 423 MODULE_LICENSE("GPL");
 424 MODULE_ALIAS("act_xt");
 425
 426 static int __init ipt_init_module(void)
 427 {
 428         int ret1, ret2;
 429
 430         ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 431         if (ret1 < 0)
 432                 pr_err("Failed to load xt action\n");
 433
 434         ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 435         if (ret2 < 0)
 436                 pr_err("Failed to load ipt action\n");
 437
 438         if (ret1 < 0 && ret2 < 0) {
 439                 return ret1;
 440         } else
 441                 return 0;
 442 }
 443
 444 static void __exit ipt_cleanup_module(void)
 445 {
 446         tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 447         tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 448 }
 449
 450 module_init(ipt_init_module);
 451 module_exit(ipt_cleanup_module);