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