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