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 (2002-4)
  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 <net/netlink.h>
  23 #include <net/pkt_sched.h>
  24 #include <linux/tc_act/tc_ipt.h>
  25 #include <net/tc_act/tc_ipt.h>
  26
  27 #include <linux/netfilter_ipv4/ip_tables.h>
  28
  29
  30 #define IPT_TAB_MASK     15
  31 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
  32 static u32 ipt_idx_gen;
  33 static DEFINE_RWLOCK(ipt_lock);
  34
  35 static struct tcf_hashinfo ipt_hash_info = {
  36         .htab   =       tcf_ipt_ht,
  37         .hmask  =       IPT_TAB_MASK,
  38         .lock   =       &ipt_lock,
  39 };
  40
  41 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
  42 {
  43         struct xt_target *target;
  44         int ret = 0;
  45
  46         target = xt_request_find_target(AF_INET, t->u.user.name,
  47                                         t->u.user.revision);
  48         if (!target)
  49                 return -ENOENT;
  50
  51         t->u.kernel.target = target;
  52
  53         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
  54                               table, hook, 0, 0);
  55         if (ret) {
  56                 module_put(t->u.kernel.target->me);
  57                 return ret;
  58         }
  59         if (t->u.kernel.target->checkentry
  60             && !t->u.kernel.target->checkentry(table, NULL,
  61                                                t->u.kernel.target, t->data,
  62                                                hook)) {
  63                 module_put(t->u.kernel.target->me);
  64                 ret = -EINVAL;
  65         }
  66
  67         return ret;
  68 }
  69
  70 static void ipt_destroy_target(struct ipt_entry_target *t)
  71 {
  72         if (t->u.kernel.target->destroy)
  73                 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
  74         module_put(t->u.kernel.target->me);
  75 }
  76
  77 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  78 {
  79         int ret = 0;
  80         if (ipt) {
  81                 if (bind)
  82                         ipt->tcf_bindcnt--;
  83                 ipt->tcf_refcnt--;
  84                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  85                         ipt_destroy_target(ipt->tcfi_t);
  86                         kfree(ipt->tcfi_tname);
  87                         kfree(ipt->tcfi_t);
  88                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
  89                         ret = ACT_P_DELETED;
  90                 }
  91         }
  92         return ret;
  93 }
  94
  95 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  96         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  97         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  98         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  99         [TCA_IPT_TARG]  = { .len = sizeof(struct ipt_entry_target) },
 100 };
 101
 102 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est,
 103                         struct tc_action *a, int ovr, int bind)
 104 {
 105         struct nlattr *tb[TCA_IPT_MAX + 1];
 106         struct tcf_ipt *ipt;
 107         struct tcf_common *pc;
 108         struct ipt_entry_target *td, *t;
 109         char *tname;
 110         int ret = 0, err;
 111         u32 hook = 0;
 112         u32 index = 0;
 113
 114         if (nla == NULL)
 115                 return -EINVAL;
 116
 117         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 118         if (err < 0)
 119                 return err;
 120
 121         if (tb[TCA_IPT_HOOK] == NULL)
 122                 return -EINVAL;
 123         if (tb[TCA_IPT_TARG] == NULL)
 124                 return -EINVAL;
 125
 126         td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 127         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 128                 return -EINVAL;
 129
 130         if (tb[TCA_IPT_INDEX] != NULL)
 131                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 132
 133         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
 134         if (!pc) {
 135                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
 136                                      &ipt_idx_gen, &ipt_hash_info);
 137                 if (unlikely(!pc))
 138                         return -ENOMEM;
 139                 ret = ACT_P_CREATED;
 140         } else {
 141                 if (!ovr) {
 142                         tcf_ipt_release(to_ipt(pc), bind);
 143                         return -EEXIST;
 144                 }
 145         }
 146         ipt = to_ipt(pc);
 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         if ((err = ipt_init_target(t, tname, hook)) < 0)
 163                 goto err3;
 164
 165         spin_lock_bh(&ipt->tcf_lock);
 166         if (ret != ACT_P_CREATED) {
 167                 ipt_destroy_target(ipt->tcfi_t);
 168                 kfree(ipt->tcfi_tname);
 169                 kfree(ipt->tcfi_t);
 170         }
 171         ipt->tcfi_tname = tname;
 172         ipt->tcfi_t     = t;
 173         ipt->tcfi_hook  = hook;
 174         spin_unlock_bh(&ipt->tcf_lock);
 175         if (ret == ACT_P_CREATED)
 176                 tcf_hash_insert(pc, &ipt_hash_info);
 177         return ret;
 178
 179 err3:
 180         kfree(t);
 181 err2:
 182         kfree(tname);
 183 err1:
 184         kfree(pc);
 185         return err;
 186 }
 187
 188 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
 189 {
 190         struct tcf_ipt *ipt = a->priv;
 191         return tcf_ipt_release(ipt, bind);
 192 }
 193
 194 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
 195                    struct tcf_result *res)
 196 {
 197         int ret = 0, result = 0;
 198         struct tcf_ipt *ipt = a->priv;
 199
 200         if (skb_cloned(skb)) {
 201                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 202                         return TC_ACT_UNSPEC;
 203         }
 204
 205         spin_lock(&ipt->tcf_lock);
 206
 207         ipt->tcf_tm.lastuse = jiffies;
 208         ipt->tcf_bstats.bytes += skb->len;
 209         ipt->tcf_bstats.packets++;
 210
 211         /* yes, we have to worry about both in and out dev
 212          worry later - danger - this API seems to have changed
 213          from earlier kernels */
 214         ret = ipt->tcfi_t->u.kernel.target->target(skb, skb->dev, NULL,
 215                                                    ipt->tcfi_hook,
 216                                                    ipt->tcfi_t->u.kernel.target,
 217                                                    ipt->tcfi_t->data);
 218         switch (ret) {
 219         case NF_ACCEPT:
 220                 result = TC_ACT_OK;
 221                 break;
 222         case NF_DROP:
 223                 result = TC_ACT_SHOT;
 224                 ipt->tcf_qstats.drops++;
 225                 break;
 226         case IPT_CONTINUE:
 227                 result = TC_ACT_PIPE;
 228                 break;
 229         default:
 230                 if (net_ratelimit())
 231                         printk("Bogus netfilter code %d assume ACCEPT\n", ret);
 232                 result = TC_POLICE_OK;
 233                 break;
 234         }
 235         spin_unlock(&ipt->tcf_lock);
 236         return result;
 237
 238 }
 239
 240 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 241 {
 242         unsigned char *b = skb_tail_pointer(skb);
 243         struct tcf_ipt *ipt = a->priv;
 244         struct ipt_entry_target *t;
 245         struct tcf_t tm;
 246         struct tc_cnt c;
 247
 248         /* for simple targets kernel size == user size
 249         ** user name = target name
 250         ** for foolproof you need to not assume this
 251         */
 252
 253         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 254         if (unlikely(!t))
 255                 goto nla_put_failure;
 256
 257         c.bindcnt = ipt->tcf_bindcnt - bind;
 258         c.refcnt = ipt->tcf_refcnt - ref;
 259         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 260
 261         NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
 262         NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index);
 263         NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook);
 264         NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
 265         NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname);
 266         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 267         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 268         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 269         NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 270         kfree(t);
 271         return skb->len;
 272
 273 nla_put_failure:
 274         nlmsg_trim(skb, b);
 275         kfree(t);
 276         return -1;
 277 }
 278
 279 static struct tc_action_ops act_ipt_ops = {
 280         .kind           =       "ipt",
 281         .hinfo          =       &ipt_hash_info,
 282         .type           =       TCA_ACT_IPT,
 283         .capab          =       TCA_CAP_NONE,
 284         .owner          =       THIS_MODULE,
 285         .act            =       tcf_ipt,
 286         .dump           =       tcf_ipt_dump,
 287         .cleanup        =       tcf_ipt_cleanup,
 288         .lookup         =       tcf_hash_search,
 289         .init           =       tcf_ipt_init,
 290         .walk           =       tcf_generic_walker
 291 };
 292
 293 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 294 MODULE_DESCRIPTION("Iptables target actions");
 295 MODULE_LICENSE("GPL");
 296
 297 static int __init ipt_init_module(void)
 298 {
 299         return tcf_register_action(&act_ipt_ops);
 300 }
 301
 302 static void __exit ipt_cleanup_module(void)
 303 {
 304         tcf_unregister_action(&act_ipt_ops);
 305 }
 306
 307 module_init(ipt_init_module);
 308 module_exit(ipt_cleanup_module);