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, struct net *net)
  69 {
  70         struct xt_tgdtor_param par = {
  71                 .target   = t->u.kernel.target,
  72                 .targinfo = t->data,
  73                 .family   = NFPROTO_IPV4,
  74                 .net      = net,
  75         };
  76         if (par.target->destroy != NULL)
  77                 par.target->destroy(&par);
  78         module_put(par.target->me);
  79 }
  80
  81 static void tcf_ipt_release(struct tc_action *a)
  82 {
  83         struct tcf_ipt *ipt = to_ipt(a);
  84
  85         if (ipt->tcfi_t) {
  86                 ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
  87                 kfree(ipt->tcfi_t);
  88         }
  89         kfree(ipt->tcfi_tname);
  90 }
  91
  92 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  93         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  94         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  95         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  96         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  97 };
  98
  99 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 100                           struct nlattr *est, struct tc_action **a,
 101                           const struct tc_action_ops *ops, int ovr, int bind)
 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(tb, TCA_IPT_MAX, nla, ipt_policy, NULL);
 117         if (err < 0)
 118                 return err;
 119
 120         if (tb[TCA_IPT_INDEX] != NULL)
 121                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 122
 123         err = tcf_idr_check_alloc(tn, &index, a, bind);
 124         if (err < 0)
 125                 return err;
 126         exists = err;
 127         if (exists && bind)
 128                 return 0;
 129
 130         if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 131                 if (exists)
 132                         tcf_idr_release(*a, bind);
 133                 else
 134                         tcf_idr_cleanup(tn, index);
 135                 return -EINVAL;
 136         }
 137
 138         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 139         if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) {
 140                 if (exists)
 141                         tcf_idr_release(*a, bind);
 142                 else
 143                         tcf_idr_cleanup(tn, index);
 144                 return -EINVAL;
 145         }
 146
 147         if (!exists) {
 148                 ret = tcf_idr_create(tn, index, est, a, ops, bind,
 149                                      false);
 150                 if (ret) {
 151                         tcf_idr_cleanup(tn, index);
 152                         return ret;
 153                 }
 154                 ret = ACT_P_CREATED;
 155         } else {
 156                 if (bind)/* dont override defaults */
 157                         return 0;
 158
 159                 if (!ovr) {
 160                         tcf_idr_release(*a, bind);
 161                         return -EEXIST;
 162                 }
 163         }
 164         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 165
 166         err = -ENOMEM;
 167         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 168         if (unlikely(!tname))
 169                 goto err1;
 170         if (tb[TCA_IPT_TABLE] == NULL ||
 171             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 172                 strcpy(tname, "mangle");
 173
 174         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 175         if (unlikely(!t))
 176                 goto err2;
 177
 178         err = ipt_init_target(net, t, tname, hook);
 179         if (err < 0)
 180                 goto err3;
 181
 182         ipt = to_ipt(*a);
 183
 184         spin_lock_bh(&ipt->tcf_lock);
 185         if (ret != ACT_P_CREATED) {
 186                 ipt_destroy_target(ipt->tcfi_t, net);
 187                 kfree(ipt->tcfi_tname);
 188                 kfree(ipt->tcfi_t);
 189         }
 190         ipt->tcfi_tname = tname;
 191         ipt->tcfi_t     = t;
 192         ipt->tcfi_hook  = hook;
 193         spin_unlock_bh(&ipt->tcf_lock);
 194         if (ret == ACT_P_CREATED)
 195                 tcf_idr_insert(tn, *a);
 196         return ret;
 197
 198 err3:
 199         kfree(t);
 200 err2:
 201         kfree(tname);
 202 err1:
 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_act(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         spin_lock_bh(&ipt->tcf_lock);
 292         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 293         if (unlikely(!t))
 294                 goto nla_put_failure;
 295
 296         c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
 297         c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
 298         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 299
 300         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 301             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 302             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 303             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 304             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 305                 goto nla_put_failure;
 306
 307         tcf_tm_dump(&tm, &ipt->tcf_tm);
 308         if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 309                 goto nla_put_failure;
 310
 311         spin_unlock_bh(&ipt->tcf_lock);
 312         kfree(t);
 313         return skb->len;
 314
 315 nla_put_failure:
 316         spin_unlock_bh(&ipt->tcf_lock);
 317         nlmsg_trim(skb, b);
 318         kfree(t);
 319         return -1;
 320 }
 321
 322 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 323                           struct netlink_callback *cb, int type,
 324                           const struct tc_action_ops *ops,
 325                           struct netlink_ext_ack *extack)
 326 {
 327         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 328
 329         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 330 }
 331
 332 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index,
 333                           struct netlink_ext_ack *extack)
 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         .type           =       TCA_ACT_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(net, 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                          struct netlink_ext_ack *extack)
 384 {
 385         struct tc_action_net *tn = net_generic(net, xt_net_id);
 386
 387         return tcf_idr_search(tn, a, index);
 388 }
 389
 390 static struct tc_action_ops act_xt_ops = {
 391         .kind           =       "xt",
 392         .type           =       TCA_ACT_XT,
 393         .owner          =       THIS_MODULE,
 394         .act            =       tcf_ipt_act,
 395         .dump           =       tcf_ipt_dump,
 396         .cleanup        =       tcf_ipt_release,
 397         .init           =       tcf_xt_init,
 398         .walk           =       tcf_xt_walker,
 399         .lookup         =       tcf_xt_search,
 400         .size           =       sizeof(struct tcf_ipt),
 401 };
 402
 403 static __net_init int xt_init_net(struct net *net)
 404 {
 405         struct tc_action_net *tn = net_generic(net, xt_net_id);
 406
 407         return tc_action_net_init(net, tn, &act_xt_ops);
 408 }
 409
 410 static void __net_exit xt_exit_net(struct list_head *net_list)
 411 {
 412         tc_action_net_exit(net_list, xt_net_id);
 413 }
 414
 415 static struct pernet_operations xt_net_ops = {
 416         .init = xt_init_net,
 417         .exit_batch = xt_exit_net,
 418         .id   = &xt_net_id,
 419         .size = sizeof(struct tc_action_net),
 420 };
 421
 422 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 423 MODULE_DESCRIPTION("Iptables target actions");
 424 MODULE_LICENSE("GPL");
 425 MODULE_ALIAS("act_xt");
 426
 427 static int __init ipt_init_module(void)
 428 {
 429         int ret1, ret2;
 430
 431         ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 432         if (ret1 < 0)
 433                 pr_err("Failed to load xt action\n");
 434
 435         ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 436         if (ret2 < 0)
 437                 pr_err("Failed to load ipt action\n");
 438
 439         if (ret1 < 0 && ret2 < 0) {
 440                 return ret1;
 441         } else
 442                 return 0;
 443 }
 444
 445 static void __exit ipt_cleanup_module(void)
 446 {
 447         tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 448         tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 449 }
 450
 451 module_init(ipt_init_module);
 452 module_exit(ipt_cleanup_module);