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