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 #define IPT_TAB_MASK     15
  32
  33 static unsigned int ipt_net_id;
  34 static struct tc_action_ops act_ipt_ops;
  35
  36 static unsigned int xt_net_id;
  37 static struct tc_action_ops act_xt_ops;
  38
  39 static int ipt_init_target(struct net *net, struct xt_entry_target *t,
  40                            char *table, unsigned int hook)
  41 {
  42         struct xt_tgchk_param par;
  43         struct xt_target *target;
  44         struct ipt_entry e = {};
  45         int ret = 0;
  46
  47         target = xt_request_find_target(AF_INET, t->u.user.name,
  48                                         t->u.user.revision);
  49         if (IS_ERR(target))
  50                 return PTR_ERR(target);
  51
  52         t->u.kernel.target = target;
  53         memset(&par, 0, sizeof(par));
  54         par.net       = net;
  55         par.table     = table;
  56         par.entryinfo = &e;
  57         par.target    = target;
  58         par.targinfo  = t->data;
  59         par.hook_mask = hook;
  60         par.family    = NFPROTO_IPV4;
  61
  62         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  63         if (ret < 0) {
  64                 module_put(t->u.kernel.target->me);
  65                 return ret;
  66         }
  67         return 0;
  68 }
  69
  70 static void ipt_destroy_target(struct xt_entry_target *t)
  71 {
  72         struct xt_tgdtor_param par = {
  73                 .target   = t->u.kernel.target,
  74                 .targinfo = t->data,
  75                 .family   = NFPROTO_IPV4,
  76         };
  77         if (par.target->destroy != NULL)
  78                 par.target->destroy(&par);
  79         module_put(par.target->me);
  80 }
  81
  82 static void tcf_ipt_release(struct tc_action *a, int bind)
  83 {
  84         struct tcf_ipt *ipt = to_ipt(a);
  85         ipt_destroy_target(ipt->tcfi_t);
  86         kfree(ipt->tcfi_tname);
  87         kfree(ipt->tcfi_t);
  88 }
  89
  90 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  91         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  92         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  93         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  94         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  95 };
  96
  97 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
  98                           struct nlattr *est, struct tc_action **a,
  99                           const struct tc_action_ops *ops, int ovr, int bind)
 100 {
 101         struct tc_action_net *tn = net_generic(net, id);
 102         struct nlattr *tb[TCA_IPT_MAX + 1];
 103         struct tcf_ipt *ipt;
 104         struct xt_entry_target *td, *t;
 105         char *tname;
 106         bool exists = false;
 107         int ret = 0, err;
 108         u32 hook = 0;
 109         u32 index = 0;
 110
 111         if (nla == NULL)
 112                 return -EINVAL;
 113
 114         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL);
 115         if (err < 0)
 116                 return err;
 117
 118         if (tb[TCA_IPT_INDEX] != NULL)
 119                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 120
 121         exists = tcf_hash_check(tn, index, a, bind);
 122         if (exists && bind)
 123                 return 0;
 124
 125         if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 126                 if (exists)
 127                         tcf_hash_release(*a, bind);
 128                 return -EINVAL;
 129         }
 130
 131         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 132         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
 133                 if (exists)
 134                         tcf_hash_release(*a, bind);
 135                 return -EINVAL;
 136         }
 137
 138         if (!exists) {
 139                 ret = tcf_hash_create(tn, index, est, a, ops, bind,
 140                                       false);
 141                 if (ret)
 142                         return ret;
 143                 ret = ACT_P_CREATED;
 144         } else {
 145                 if (bind)/* dont override defaults */
 146                         return 0;
 147                 tcf_hash_release(*a, bind);
 148
 149                 if (!ovr)
 150                         return -EEXIST;
 151         }
 152         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 153
 154         err = -ENOMEM;
 155         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 156         if (unlikely(!tname))
 157                 goto err1;
 158         if (tb[TCA_IPT_TABLE] == NULL ||
 159             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 160                 strcpy(tname, "mangle");
 161
 162         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 163         if (unlikely(!t))
 164                 goto err2;
 165
 166         err = ipt_init_target(net, t, tname, hook);
 167         if (err < 0)
 168                 goto err3;
 169
 170         ipt = to_ipt(*a);
 171
 172         spin_lock_bh(&ipt->tcf_lock);
 173         if (ret != ACT_P_CREATED) {
 174                 ipt_destroy_target(ipt->tcfi_t);
 175                 kfree(ipt->tcfi_tname);
 176                 kfree(ipt->tcfi_t);
 177         }
 178         ipt->tcfi_tname = tname;
 179         ipt->tcfi_t     = t;
 180         ipt->tcfi_hook  = hook;
 181         spin_unlock_bh(&ipt->tcf_lock);
 182         if (ret == ACT_P_CREATED)
 183                 tcf_hash_insert(tn, *a);
 184         return ret;
 185
 186 err3:
 187         kfree(t);
 188 err2:
 189         kfree(tname);
 190 err1:
 191         if (ret == ACT_P_CREATED)
 192                 tcf_hash_cleanup(*a, est);
 193         return err;
 194 }
 195
 196 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 197                         struct nlattr *est, struct tc_action **a, int ovr,
 198                         int bind)
 199 {
 200         return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
 201                               bind);
 202 }
 203
 204 static int tcf_xt_init(struct net *net, struct nlattr *nla,
 205                        struct nlattr *est, struct tc_action **a, int ovr,
 206                        int bind)
 207 {
 208         return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
 209                               bind);
 210 }
 211
 212 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
 213                    struct tcf_result *res)
 214 {
 215         int ret = 0, result = 0;
 216         struct tcf_ipt *ipt = to_ipt(a);
 217         struct xt_action_param par;
 218         struct nf_hook_state state = {
 219                 .net    = dev_net(skb->dev),
 220                 .in     = skb->dev,
 221                 .hook   = ipt->tcfi_hook,
 222                 .pf     = NFPROTO_IPV4,
 223         };
 224
 225         if (skb_unclone(skb, GFP_ATOMIC))
 226                 return TC_ACT_UNSPEC;
 227
 228         spin_lock(&ipt->tcf_lock);
 229
 230         tcf_lastuse_update(&ipt->tcf_tm);
 231         bstats_update(&ipt->tcf_bstats, skb);
 232
 233         /* yes, we have to worry about both in and out dev
 234          * worry later - danger - this API seems to have changed
 235          * from earlier kernels
 236          */
 237         par.state    = &state;
 238         par.target   = ipt->tcfi_t->u.kernel.target;
 239         par.targinfo = ipt->tcfi_t->data;
 240         ret = par.target->target(skb, &par);
 241
 242         switch (ret) {
 243         case NF_ACCEPT:
 244                 result = TC_ACT_OK;
 245                 break;
 246         case NF_DROP:
 247                 result = TC_ACT_SHOT;
 248                 ipt->tcf_qstats.drops++;
 249                 break;
 250         case XT_CONTINUE:
 251                 result = TC_ACT_PIPE;
 252                 break;
 253         default:
 254                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 255                                        ret);
 256                 result = TC_ACT_OK;
 257                 break;
 258         }
 259         spin_unlock(&ipt->tcf_lock);
 260         return result;
 261
 262 }
 263
 264 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 265                         int ref)
 266 {
 267         unsigned char *b = skb_tail_pointer(skb);
 268         struct tcf_ipt *ipt = to_ipt(a);
 269         struct xt_entry_target *t;
 270         struct tcf_t tm;
 271         struct tc_cnt c;
 272
 273         /* for simple targets kernel size == user size
 274          * user name = target name
 275          * for foolproof you need to not assume this
 276          */
 277
 278         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 279         if (unlikely(!t))
 280                 goto nla_put_failure;
 281
 282         c.bindcnt = ipt->tcf_bindcnt - bind;
 283         c.refcnt = ipt->tcf_refcnt - ref;
 284         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 285
 286         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 287             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 288             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 289             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 290             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 291                 goto nla_put_failure;
 292
 293         tcf_tm_dump(&tm, &ipt->tcf_tm);
 294         if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 295                 goto nla_put_failure;
 296
 297         kfree(t);
 298         return skb->len;
 299
 300 nla_put_failure:
 301         nlmsg_trim(skb, b);
 302         kfree(t);
 303         return -1;
 304 }
 305
 306 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 307                           struct netlink_callback *cb, int type,
 308                           const struct tc_action_ops *ops)
 309 {
 310         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 311
 312         return tcf_generic_walker(tn, skb, cb, type, ops);
 313 }
 314
 315 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
 316 {
 317         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 318
 319         return tcf_hash_search(tn, a, index);
 320 }
 321
 322 static struct tc_action_ops act_ipt_ops = {
 323         .kind           =       "ipt",
 324         .type           =       TCA_ACT_IPT,
 325         .owner          =       THIS_MODULE,
 326         .act            =       tcf_ipt,
 327         .dump           =       tcf_ipt_dump,
 328         .cleanup        =       tcf_ipt_release,
 329         .init           =       tcf_ipt_init,
 330         .walk           =       tcf_ipt_walker,
 331         .lookup         =       tcf_ipt_search,
 332         .size           =       sizeof(struct tcf_ipt),
 333 };
 334
 335 static __net_init int ipt_init_net(struct net *net)
 336 {
 337         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 338
 339         return tc_action_net_init(tn, &act_ipt_ops, IPT_TAB_MASK);
 340 }
 341
 342 static void __net_exit ipt_exit_net(struct net *net)
 343 {
 344         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 345
 346         tc_action_net_exit(tn);
 347 }
 348
 349 static struct pernet_operations ipt_net_ops = {
 350         .init = ipt_init_net,
 351         .exit = ipt_exit_net,
 352         .id   = &ipt_net_id,
 353         .size = sizeof(struct tc_action_net),
 354 };
 355
 356 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
 357                          struct netlink_callback *cb, int type,
 358                          const struct tc_action_ops *ops)
 359 {
 360         struct tc_action_net *tn = net_generic(net, xt_net_id);
 361
 362         return tcf_generic_walker(tn, skb, cb, type, ops);
 363 }
 364
 365 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
 366 {
 367         struct tc_action_net *tn = net_generic(net, xt_net_id);
 368
 369         return tcf_hash_search(tn, a, index);
 370 }
 371
 372 static struct tc_action_ops act_xt_ops = {
 373         .kind           =       "xt",
 374         .type           =       TCA_ACT_XT,
 375         .owner          =       THIS_MODULE,
 376         .act            =       tcf_ipt,
 377         .dump           =       tcf_ipt_dump,
 378         .cleanup        =       tcf_ipt_release,
 379         .init           =       tcf_xt_init,
 380         .walk           =       tcf_xt_walker,
 381         .lookup         =       tcf_xt_search,
 382         .size           =       sizeof(struct tcf_ipt),
 383 };
 384
 385 static __net_init int xt_init_net(struct net *net)
 386 {
 387         struct tc_action_net *tn = net_generic(net, xt_net_id);
 388
 389         return tc_action_net_init(tn, &act_xt_ops, IPT_TAB_MASK);
 390 }
 391
 392 static void __net_exit xt_exit_net(struct net *net)
 393 {
 394         struct tc_action_net *tn = net_generic(net, xt_net_id);
 395
 396         tc_action_net_exit(tn);
 397 }
 398
 399 static struct pernet_operations xt_net_ops = {
 400         .init = xt_init_net,
 401         .exit = xt_exit_net,
 402         .id   = &xt_net_id,
 403         .size = sizeof(struct tc_action_net),
 404 };
 405
 406 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 407 MODULE_DESCRIPTION("Iptables target actions");
 408 MODULE_LICENSE("GPL");
 409 MODULE_ALIAS("act_xt");
 410
 411 static int __init ipt_init_module(void)
 412 {
 413         int ret1, ret2;
 414
 415         ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 416         if (ret1 < 0)
 417                 pr_err("Failed to load xt action\n");
 418
 419         ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 420         if (ret2 < 0)
 421                 pr_err("Failed to load ipt action\n");
 422
 423         if (ret1 < 0 && ret2 < 0) {
 424                 return ret1;
 425         } else
 426                 return 0;
 427 }
 428
 429 static void __exit ipt_cleanup_module(void)
 430 {
 431         tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 432         tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 433 }
 434
 435 module_init(ipt_init_module);
 436 module_exit(ipt_cleanup_module);