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