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 {
 102         struct tc_action_net *tn = net_generic(net, id);
 103         struct nlattr *tb[TCA_IPT_MAX + 1];
 104         struct tcf_ipt *ipt;
 105         struct xt_entry_target *td, *t;
 106         char *tname;
 107         bool exists = false;
 108         int ret = 0, err;
 109         u32 hook = 0;
 110         u32 index = 0;
 111
 112         if (nla == NULL)
 113                 return -EINVAL;
 114
 115         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL);
 116         if (err < 0)
 117                 return err;
 118
 119         if (tb[TCA_IPT_INDEX] != NULL)
 120                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 121
 122         err = tcf_idr_check_alloc(tn, &index, a, bind);
 123         if (err < 0)
 124                 return err;
 125         exists = err;
 126         if (exists && bind)
 127                 return 0;
 128
 129         if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 130                 if (exists)
 131                         tcf_idr_release(*a, bind);
 132                 else
 133                         tcf_idr_cleanup(tn, index);
 134                 return -EINVAL;
 135         }
 136
 137         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 138         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
 139                 if (exists)
 140                         tcf_idr_release(*a, bind);
 141                 else
 142                         tcf_idr_cleanup(tn, index);
 143                 return -EINVAL;
 144         }
 145
 146         if (!exists) {
 147                 ret = tcf_idr_create(tn, index, est, a, ops, bind,
 148                                      false);
 149                 if (ret) {
 150                         tcf_idr_cleanup(tn, index);
 151                         return ret;
 152                 }
 153                 ret = ACT_P_CREATED;
 154         } else {
 155                 if (bind)/* dont override defaults */
 156                         return 0;
 157
 158                 if (!ovr) {
 159                         tcf_idr_release(*a, bind);
 160                         return -EEXIST;
 161                 }
 162         }
 163         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 164
 165         err = -ENOMEM;
 166         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 167         if (unlikely(!tname))
 168                 goto err1;
 169         if (tb[TCA_IPT_TABLE] == NULL ||
 170             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 171                 strcpy(tname, "mangle");
 172
 173         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 174         if (unlikely(!t))
 175                 goto err2;
 176
 177         err = ipt_init_target(net, t, tname, hook);
 178         if (err < 0)
 179                 goto err3;
 180
 181         ipt = to_ipt(*a);
 182
 183         spin_lock_bh(&ipt->tcf_lock);
 184         if (ret != ACT_P_CREATED) {
 185                 ipt_destroy_target(ipt->tcfi_t);
 186                 kfree(ipt->tcfi_tname);
 187                 kfree(ipt->tcfi_t);
 188         }
 189         ipt->tcfi_tname = tname;
 190         ipt->tcfi_t     = t;
 191         ipt->tcfi_hook  = hook;
 192         spin_unlock_bh(&ipt->tcf_lock);
 193         if (ret == ACT_P_CREATED)
 194                 tcf_idr_insert(tn, *a);
 195         return ret;
 196
 197 err3:
 198         kfree(t);
 199 err2:
 200         kfree(tname);
 201 err1:
 202         if (ret == ACT_P_CREATED)
 203                 tcf_idr_release(*a, bind);
 204         return err;
 205 }
 206
 207 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 208                         struct nlattr *est, struct tc_action **a, int ovr,
 209                         int bind, bool rtnl_held,
 210                         struct netlink_ext_ack *extack)
 211 {
 212         return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
 213                               bind);
 214 }
 215
 216 static int tcf_xt_init(struct net *net, struct nlattr *nla,
 217                        struct nlattr *est, struct tc_action **a, int ovr,
 218                        int bind, bool unlocked,
 219                        struct netlink_ext_ack *extack)
 220 {
 221         return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
 222                               bind);
 223 }
 224
 225 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
 226                    struct tcf_result *res)
 227 {
 228         int ret = 0, result = 0;
 229         struct tcf_ipt *ipt = to_ipt(a);
 230         struct xt_action_param par;
 231         struct nf_hook_state state = {
 232                 .net    = dev_net(skb->dev),
 233                 .in     = skb->dev,
 234                 .hook   = ipt->tcfi_hook,
 235                 .pf     = NFPROTO_IPV4,
 236         };
 237
 238         if (skb_unclone(skb, GFP_ATOMIC))
 239                 return TC_ACT_UNSPEC;
 240
 241         spin_lock(&ipt->tcf_lock);
 242
 243         tcf_lastuse_update(&ipt->tcf_tm);
 244         bstats_update(&ipt->tcf_bstats, skb);
 245
 246         /* yes, we have to worry about both in and out dev
 247          * worry later - danger - this API seems to have changed
 248          * from earlier kernels
 249          */
 250         par.state    = &state;
 251         par.target   = ipt->tcfi_t->u.kernel.target;
 252         par.targinfo = ipt->tcfi_t->data;
 253         ret = par.target->target(skb, &par);
 254
 255         switch (ret) {
 256         case NF_ACCEPT:
 257                 result = TC_ACT_OK;
 258                 break;
 259         case NF_DROP:
 260                 result = TC_ACT_SHOT;
 261                 ipt->tcf_qstats.drops++;
 262                 break;
 263         case XT_CONTINUE:
 264                 result = TC_ACT_PIPE;
 265                 break;
 266         default:
 267                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 268                                        ret);
 269                 result = TC_ACT_OK;
 270                 break;
 271         }
 272         spin_unlock(&ipt->tcf_lock);
 273         return result;
 274
 275 }
 276
 277 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 278                         int ref)
 279 {
 280         unsigned char *b = skb_tail_pointer(skb);
 281         struct tcf_ipt *ipt = to_ipt(a);
 282         struct xt_entry_target *t;
 283         struct tcf_t tm;
 284         struct tc_cnt c;
 285
 286         /* for simple targets kernel size == user size
 287          * user name = target name
 288          * for foolproof you need to not assume this
 289          */
 290
 291         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 292         if (unlikely(!t))
 293                 goto nla_put_failure;
 294
 295         c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
 296         c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
 297         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 298
 299         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 300             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 301             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 302             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 303             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 304                 goto nla_put_failure;
 305
 306         tcf_tm_dump(&tm, &ipt->tcf_tm);
 307         if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 308                 goto nla_put_failure;
 309
 310         kfree(t);
 311         return skb->len;
 312
 313 nla_put_failure:
 314         nlmsg_trim(skb, b);
 315         kfree(t);
 316         return -1;
 317 }
 318
 319 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 320                           struct netlink_callback *cb, int type,
 321                           const struct tc_action_ops *ops,
 322                           struct netlink_ext_ack *extack)
 323 {
 324         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 325
 326         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 327 }
 328
 329 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index,
 330                           struct netlink_ext_ack *extack)
 331 {
 332         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 333
 334         return tcf_idr_search(tn, a, index);
 335 }
 336
 337 static int tcf_ipt_delete(struct net *net, u32 index)
 338 {
 339         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 340
 341         return tcf_idr_delete_index(tn, index);
 342 }
 343
 344 static struct tc_action_ops act_ipt_ops = {
 345         .kind           =       "ipt",
 346         .type           =       TCA_ACT_IPT,
 347         .owner          =       THIS_MODULE,
 348         .act            =       tcf_ipt,
 349         .dump           =       tcf_ipt_dump,
 350         .cleanup        =       tcf_ipt_release,
 351         .init           =       tcf_ipt_init,
 352         .walk           =       tcf_ipt_walker,
 353         .lookup         =       tcf_ipt_search,
 354         .delete         =       tcf_ipt_delete,
 355         .size           =       sizeof(struct tcf_ipt),
 356 };
 357
 358 static __net_init int ipt_init_net(struct net *net)
 359 {
 360         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 361
 362         return tc_action_net_init(tn, &act_ipt_ops);
 363 }
 364
 365 static void __net_exit ipt_exit_net(struct list_head *net_list)
 366 {
 367         tc_action_net_exit(net_list, ipt_net_id);
 368 }
 369
 370 static struct pernet_operations ipt_net_ops = {
 371         .init = ipt_init_net,
 372         .exit_batch = ipt_exit_net,
 373         .id   = &ipt_net_id,
 374         .size = sizeof(struct tc_action_net),
 375 };
 376
 377 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
 378                          struct netlink_callback *cb, int type,
 379                          const struct tc_action_ops *ops,
 380                          struct netlink_ext_ack *extack)
 381 {
 382         struct tc_action_net *tn = net_generic(net, xt_net_id);
 383
 384         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 385 }
 386
 387 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index,
 388                          struct netlink_ext_ack *extack)
 389 {
 390         struct tc_action_net *tn = net_generic(net, xt_net_id);
 391
 392         return tcf_idr_search(tn, a, index);
 393 }
 394
 395 static int tcf_xt_delete(struct net *net, u32 index)
 396 {
 397         struct tc_action_net *tn = net_generic(net, xt_net_id);
 398
 399         return tcf_idr_delete_index(tn, index);
 400 }
 401
 402 static struct tc_action_ops act_xt_ops = {
 403         .kind           =       "xt",
 404         .type           =       TCA_ACT_XT,
 405         .owner          =       THIS_MODULE,
 406         .act            =       tcf_ipt,
 407         .dump           =       tcf_ipt_dump,
 408         .cleanup        =       tcf_ipt_release,
 409         .init           =       tcf_xt_init,
 410         .walk           =       tcf_xt_walker,
 411         .lookup         =       tcf_xt_search,
 412         .delete         =       tcf_xt_delete,
 413         .size           =       sizeof(struct tcf_ipt),
 414 };
 415
 416 static __net_init int xt_init_net(struct net *net)
 417 {
 418         struct tc_action_net *tn = net_generic(net, xt_net_id);
 419
 420         return tc_action_net_init(tn, &act_xt_ops);
 421 }
 422
 423 static void __net_exit xt_exit_net(struct list_head *net_list)
 424 {
 425         tc_action_net_exit(net_list, xt_net_id);
 426 }
 427
 428 static struct pernet_operations xt_net_ops = {
 429         .init = xt_init_net,
 430         .exit_batch = xt_exit_net,
 431         .id   = &xt_net_id,
 432         .size = sizeof(struct tc_action_net),
 433 };
 434
 435 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 436 MODULE_DESCRIPTION("Iptables target actions");
 437 MODULE_LICENSE("GPL");
 438 MODULE_ALIAS("act_xt");
 439
 440 static int __init ipt_init_module(void)
 441 {
 442         int ret1, ret2;
 443
 444         ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 445         if (ret1 < 0)
 446                 pr_err("Failed to load xt action\n");
 447
 448         ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 449         if (ret2 < 0)
 450                 pr_err("Failed to load ipt action\n");
 451
 452         if (ret1 < 0 && ret2 < 0) {
 453                 return ret1;
 454         } else
 455                 return 0;
 456 }
 457
 458 static void __exit ipt_cleanup_module(void)
 459 {
 460         tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 461         tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 462 }
 463
 464 module_init(ipt_init_module);
 465 module_exit(ipt_cleanup_module);