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