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