net/sched/act_ipt.c

   1 /*
   2  * net/sched/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 static u32 ipt_idx_gen;
  33 static struct tcf_hashinfo ipt_hash_info;
  34
  35 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
  36 {
  37         struct xt_tgchk_param par;
  38         struct xt_target *target;
  39         int ret = 0;
  40
  41         target = xt_request_find_target(AF_INET, t->u.user.name,
  42                                         t->u.user.revision);
  43         if (IS_ERR(target))
  44                 return PTR_ERR(target);
  45
  46         t->u.kernel.target = target;
  47         par.table     = table;
  48         par.entryinfo = NULL;
  49         par.target    = target;
  50         par.targinfo  = t->data;
  51         par.hook_mask = hook;
  52         par.family    = NFPROTO_IPV4;
  53
  54         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  55         if (ret < 0) {
  56                 module_put(t->u.kernel.target->me);
  57                 return ret;
  58         }
  59         return 0;
  60 }
  61
  62 static void ipt_destroy_target(struct xt_entry_target *t)
  63 {
  64         struct xt_tgdtor_param par = {
  65                 .target   = t->u.kernel.target,
  66                 .targinfo = t->data,
  67         };
  68         if (par.target->destroy != NULL)
  69                 par.target->destroy(&par);
  70         module_put(par.target->me);
  71 }
  72
  73 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  74 {
  75         int ret = 0;
  76         if (ipt) {
  77                 if (bind)
  78                         ipt->tcf_bindcnt--;
  79                 ipt->tcf_refcnt--;
  80                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  81                         ipt_destroy_target(ipt->tcfi_t);
  82                         kfree(ipt->tcfi_tname);
  83                         kfree(ipt->tcfi_t);
  84                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
  85                         ret = ACT_P_DELETED;
  86                 }
  87         }
  88         return ret;
  89 }
  90
  91 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  92         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  93         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  94         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  95         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  96 };
  97
  98 static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est,
  99                         struct tc_action *a, int ovr, int bind)
 100 {
 101         struct nlattr *tb[TCA_IPT_MAX + 1];
 102         struct tcf_ipt *ipt;
 103         struct tcf_common *pc;
 104         struct xt_entry_target *td, *t;
 105         char *tname;
 106         int ret = 0, err;
 107         u32 hook = 0;
 108         u32 index = 0;
 109
 110         if (nla == NULL)
 111                 return -EINVAL;
 112
 113         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 114         if (err < 0)
 115                 return err;
 116
 117         if (tb[TCA_IPT_HOOK] == NULL)
 118                 return -EINVAL;
 119         if (tb[TCA_IPT_TARG] == NULL)
 120                 return -EINVAL;
 121
 122         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 123         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 124                 return -EINVAL;
 125
 126         if (tb[TCA_IPT_INDEX] != NULL)
 127                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 128
 129         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
 130         if (!pc) {
 131                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
 132                                      &ipt_idx_gen, &ipt_hash_info);
 133                 if (IS_ERR(pc))
 134                         return PTR_ERR(pc);
 135                 ret = ACT_P_CREATED;
 136         } else {
 137                 if (bind)/* dont override defaults */
 138                         return 0;
 139                 tcf_ipt_release(to_ipt(pc), bind);
 140
 141                 if (!ovr)
 142                         return -EEXIST;
 143         }
 144         ipt = to_ipt(pc);
 145
 146         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 147
 148         err = -ENOMEM;
 149         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 150         if (unlikely(!tname))
 151                 goto err1;
 152         if (tb[TCA_IPT_TABLE] == NULL ||
 153             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 154                 strcpy(tname, "mangle");
 155
 156         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 157         if (unlikely(!t))
 158                 goto err2;
 159
 160         err = ipt_init_target(t, tname, hook);
 161         if (err < 0)
 162                 goto err3;
 163
 164         spin_lock_bh(&ipt->tcf_lock);
 165         if (ret != ACT_P_CREATED) {
 166                 ipt_destroy_target(ipt->tcfi_t);
 167                 kfree(ipt->tcfi_tname);
 168                 kfree(ipt->tcfi_t);
 169         }
 170         ipt->tcfi_tname = tname;
 171         ipt->tcfi_t     = t;
 172         ipt->tcfi_hook  = hook;
 173         spin_unlock_bh(&ipt->tcf_lock);
 174         if (ret == ACT_P_CREATED)
 175                 tcf_hash_insert(pc, &ipt_hash_info);
 176         return ret;
 177
 178 err3:
 179         kfree(t);
 180 err2:
 181         kfree(tname);
 182 err1:
 183         if (ret == ACT_P_CREATED) {
 184                 if (est)
 185                         gen_kill_estimator(&pc->tcfc_bstats,
 186                                            &pc->tcfc_rate_est);
 187                 kfree_rcu(pc, tcfc_rcu);
 188         }
 189         return err;
 190 }
 191
 192 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
 193 {
 194         struct tcf_ipt *ipt = a->priv;
 195         return tcf_ipt_release(ipt, 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.in       = skb->dev;
 218         par.out      = NULL;
 219         par.hooknum  = ipt->tcfi_hook;
 220         par.target   = ipt->tcfi_t->u.kernel.target;
 221         par.targinfo = ipt->tcfi_t->data;
 222         ret = par.target->target(skb, &par);
 223
 224         switch (ret) {
 225         case NF_ACCEPT:
 226                 result = TC_ACT_OK;
 227                 break;
 228         case NF_DROP:
 229                 result = TC_ACT_SHOT;
 230                 ipt->tcf_qstats.drops++;
 231                 break;
 232         case XT_CONTINUE:
 233                 result = TC_ACT_PIPE;
 234                 break;
 235         default:
 236                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 237                                        ret);
 238                 result = TC_POLICE_OK;
 239                 break;
 240         }
 241         spin_unlock(&ipt->tcf_lock);
 242         return result;
 243
 244 }
 245
 246 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 247 {
 248         unsigned char *b = skb_tail_pointer(skb);
 249         struct tcf_ipt *ipt = a->priv;
 250         struct xt_entry_target *t;
 251         struct tcf_t tm;
 252         struct tc_cnt c;
 253
 254         /* for simple targets kernel size == user size
 255          * user name = target name
 256          * for foolproof you need to not assume this
 257          */
 258
 259         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 260         if (unlikely(!t))
 261                 goto nla_put_failure;
 262
 263         c.bindcnt = ipt->tcf_bindcnt - bind;
 264         c.refcnt = ipt->tcf_refcnt - ref;
 265         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 266
 267         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 268             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 269             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 270             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 271             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 272                 goto nla_put_failure;
 273         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 274         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 275         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 276         if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
 277                 goto nla_put_failure;
 278         kfree(t);
 279         return skb->len;
 280
 281 nla_put_failure:
 282         nlmsg_trim(skb, b);
 283         kfree(t);
 284         return -1;
 285 }
 286
 287 static struct tc_action_ops act_ipt_ops = {
 288         .kind           =       "ipt",
 289         .hinfo          =       &ipt_hash_info,
 290         .type           =       TCA_ACT_IPT,
 291         .capab          =       TCA_CAP_NONE,
 292         .owner          =       THIS_MODULE,
 293         .act            =       tcf_ipt,
 294         .dump           =       tcf_ipt_dump,
 295         .cleanup        =       tcf_ipt_cleanup,
 296         .init           =       tcf_ipt_init,
 297 };
 298
 299 static struct tc_action_ops act_xt_ops = {
 300         .kind           =       "xt",
 301         .hinfo          =       &ipt_hash_info,
 302         .type           =       TCA_ACT_IPT,
 303         .capab          =       TCA_CAP_NONE,
 304         .owner          =       THIS_MODULE,
 305         .act            =       tcf_ipt,
 306         .dump           =       tcf_ipt_dump,
 307         .cleanup        =       tcf_ipt_cleanup,
 308         .init           =       tcf_ipt_init,
 309 };
 310
 311 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 312 MODULE_DESCRIPTION("Iptables target actions");
 313 MODULE_LICENSE("GPL");
 314 MODULE_ALIAS("act_xt");
 315
 316 static int __init ipt_init_module(void)
 317 {
 318         int ret1, ret2, err;
 319         err = tcf_hashinfo_init(&ipt_hash_info, IPT_TAB_MASK);
 320         if (err)
 321                 return err;
 322
 323         ret1 = tcf_register_action(&act_xt_ops);
 324         if (ret1 < 0)
 325                 printk("Failed to load xt action\n");
 326         ret2 = tcf_register_action(&act_ipt_ops);
 327         if (ret2 < 0)
 328                 printk("Failed to load ipt action\n");
 329
 330         if (ret1 < 0 && ret2 < 0) {
 331                 tcf_hashinfo_destroy(&ipt_hash_info);
 332                 return ret1;
 333         } else
 334                 return 0;
 335 }
 336
 337 static void __exit ipt_cleanup_module(void)
 338 {
 339         tcf_unregister_action(&act_xt_ops);
 340         tcf_unregister_action(&act_ipt_ops);
 341         tcf_hashinfo_destroy(&ipt_hash_info);
 342 }
 343
 344 module_init(ipt_init_module);
 345 module_exit(ipt_cleanup_module);