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