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 struct tcf_hashinfo ipt_hash_info;
  33
  34 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
  35 {
  36         struct xt_tgchk_param par;
  37         struct xt_target *target;
  38         int ret = 0;
  39
  40         target = xt_request_find_target(AF_INET, t->u.user.name,
  41                                         t->u.user.revision);
  42         if (IS_ERR(target))
  43                 return PTR_ERR(target);
  44
  45         t->u.kernel.target = target;
  46         par.table     = table;
  47         par.entryinfo = NULL;
  48         par.target    = target;
  49         par.targinfo  = t->data;
  50         par.hook_mask = hook;
  51         par.family    = NFPROTO_IPV4;
  52
  53         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  54         if (ret < 0) {
  55                 module_put(t->u.kernel.target->me);
  56                 return ret;
  57         }
  58         return 0;
  59 }
  60
  61 static void ipt_destroy_target(struct xt_entry_target *t)
  62 {
  63         struct xt_tgdtor_param par = {
  64                 .target   = t->u.kernel.target,
  65                 .targinfo = t->data,
  66         };
  67         if (par.target->destroy != NULL)
  68                 par.target->destroy(&par);
  69         module_put(par.target->me);
  70 }
  71
  72 static int tcf_ipt_release(struct tc_action *a, int bind)
  73 {
  74         struct tcf_ipt *ipt = to_ipt(a);
  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(a);
  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 xt_entry_target *td, *t;
 104         char *tname;
 105         int ret = 0, err;
 106         u32 hook = 0;
 107         u32 index = 0;
 108
 109         if (nla == NULL)
 110                 return -EINVAL;
 111
 112         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 113         if (err < 0)
 114                 return err;
 115
 116         if (tb[TCA_IPT_HOOK] == NULL)
 117                 return -EINVAL;
 118         if (tb[TCA_IPT_TARG] == NULL)
 119                 return -EINVAL;
 120
 121         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 122         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 123                 return -EINVAL;
 124
 125         if (tb[TCA_IPT_INDEX] != NULL)
 126                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 127
 128         if (!tcf_hash_check(index, a, bind) ) {
 129                 ret = tcf_hash_create(index, est, a, sizeof(*ipt), bind);
 130                 if (ret)
 131                         return ret;
 132                 ret = ACT_P_CREATED;
 133         } else {
 134                 if (bind)/* dont override defaults */
 135                         return 0;
 136                 tcf_ipt_release(a, bind);
 137
 138                 if (!ovr)
 139                         return -EEXIST;
 140         }
 141         ipt = to_ipt(a);
 142
 143         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 144
 145         err = -ENOMEM;
 146         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 147         if (unlikely(!tname))
 148                 goto err1;
 149         if (tb[TCA_IPT_TABLE] == NULL ||
 150             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 151                 strcpy(tname, "mangle");
 152
 153         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 154         if (unlikely(!t))
 155                 goto err2;
 156
 157         err = ipt_init_target(t, tname, hook);
 158         if (err < 0)
 159                 goto err3;
 160
 161         spin_lock_bh(&ipt->tcf_lock);
 162         if (ret != ACT_P_CREATED) {
 163                 ipt_destroy_target(ipt->tcfi_t);
 164                 kfree(ipt->tcfi_tname);
 165                 kfree(ipt->tcfi_t);
 166         }
 167         ipt->tcfi_tname = tname;
 168         ipt->tcfi_t     = t;
 169         ipt->tcfi_hook  = hook;
 170         spin_unlock_bh(&ipt->tcf_lock);
 171         if (ret == ACT_P_CREATED)
 172                 tcf_hash_insert(a);
 173         return ret;
 174
 175 err3:
 176         kfree(t);
 177 err2:
 178         kfree(tname);
 179 err1:
 180         if (ret == ACT_P_CREATED)
 181                 tcf_hash_cleanup(a, est);
 182         return err;
 183 }
 184
 185 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
 186                    struct tcf_result *res)
 187 {
 188         int ret = 0, result = 0;
 189         struct tcf_ipt *ipt = a->priv;
 190         struct xt_action_param par;
 191
 192         if (skb_unclone(skb, GFP_ATOMIC))
 193                 return TC_ACT_UNSPEC;
 194
 195         spin_lock(&ipt->tcf_lock);
 196
 197         ipt->tcf_tm.lastuse = jiffies;
 198         bstats_update(&ipt->tcf_bstats, skb);
 199
 200         /* yes, we have to worry about both in and out dev
 201          * worry later - danger - this API seems to have changed
 202          * from earlier kernels
 203          */
 204         par.in       = skb->dev;
 205         par.out      = NULL;
 206         par.hooknum  = ipt->tcfi_hook;
 207         par.target   = ipt->tcfi_t->u.kernel.target;
 208         par.targinfo = ipt->tcfi_t->data;
 209         ret = par.target->target(skb, &par);
 210
 211         switch (ret) {
 212         case NF_ACCEPT:
 213                 result = TC_ACT_OK;
 214                 break;
 215         case NF_DROP:
 216                 result = TC_ACT_SHOT;
 217                 ipt->tcf_qstats.drops++;
 218                 break;
 219         case XT_CONTINUE:
 220                 result = TC_ACT_PIPE;
 221                 break;
 222         default:
 223                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 224                                        ret);
 225                 result = TC_POLICE_OK;
 226                 break;
 227         }
 228         spin_unlock(&ipt->tcf_lock);
 229         return result;
 230
 231 }
 232
 233 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 234 {
 235         unsigned char *b = skb_tail_pointer(skb);
 236         struct tcf_ipt *ipt = a->priv;
 237         struct xt_entry_target *t;
 238         struct tcf_t tm;
 239         struct tc_cnt c;
 240
 241         /* for simple targets kernel size == user size
 242          * user name = target name
 243          * for foolproof you need to not assume this
 244          */
 245
 246         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 247         if (unlikely(!t))
 248                 goto nla_put_failure;
 249
 250         c.bindcnt = ipt->tcf_bindcnt - bind;
 251         c.refcnt = ipt->tcf_refcnt - ref;
 252         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 253
 254         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 255             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 256             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 257             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 258             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 259                 goto nla_put_failure;
 260         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 261         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 262         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 263         if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
 264                 goto nla_put_failure;
 265         kfree(t);
 266         return skb->len;
 267
 268 nla_put_failure:
 269         nlmsg_trim(skb, b);
 270         kfree(t);
 271         return -1;
 272 }
 273
 274 static struct tc_action_ops act_ipt_ops = {
 275         .kind           =       "ipt",
 276         .hinfo          =       &ipt_hash_info,
 277         .type           =       TCA_ACT_IPT,
 278         .owner          =       THIS_MODULE,
 279         .act            =       tcf_ipt,
 280         .dump           =       tcf_ipt_dump,
 281         .cleanup        =       tcf_ipt_release,
 282         .init           =       tcf_ipt_init,
 283 };
 284
 285 static struct tc_action_ops act_xt_ops = {
 286         .kind           =       "xt",
 287         .hinfo          =       &ipt_hash_info,
 288         .type           =       TCA_ACT_XT,
 289         .owner          =       THIS_MODULE,
 290         .act            =       tcf_ipt,
 291         .dump           =       tcf_ipt_dump,
 292         .cleanup        =       tcf_ipt_release,
 293         .init           =       tcf_ipt_init,
 294 };
 295
 296 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 297 MODULE_DESCRIPTION("Iptables target actions");
 298 MODULE_LICENSE("GPL");
 299 MODULE_ALIAS("act_xt");
 300
 301 static int __init ipt_init_module(void)
 302 {
 303         int ret1, ret2, err;
 304         err = tcf_hashinfo_init(&ipt_hash_info, IPT_TAB_MASK);
 305         if (err)
 306                 return err;
 307
 308         ret1 = tcf_register_action(&act_xt_ops);
 309         if (ret1 < 0)
 310                 printk("Failed to load xt action\n");
 311         ret2 = tcf_register_action(&act_ipt_ops);
 312         if (ret2 < 0)
 313                 printk("Failed to load ipt action\n");
 314
 315         if (ret1 < 0 && ret2 < 0) {
 316                 tcf_hashinfo_destroy(&ipt_hash_info);
 317                 return ret1;
 318         } else
 319                 return 0;
 320 }
 321
 322 static void __exit ipt_cleanup_module(void)
 323 {
 324         tcf_unregister_action(&act_xt_ops);
 325         tcf_unregister_action(&act_ipt_ops);
 326         tcf_hashinfo_destroy(&ipt_hash_info);
 327 }
 328
 329 module_init(ipt_init_module);
 330 module_exit(ipt_cleanup_module);