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   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_tgchk_param par;
  44         struct xt_target *target;
  45         int ret = 0;
  46
  47         target = xt_request_find_target(AF_INET, t->u.user.name,
  48                                         t->u.user.revision);
  49         if (!target)
  50                 return -ENOENT;
  51
  52         t->u.kernel.target = target;
  53         par.table     = table;
  54         par.entryinfo = NULL;
  55         par.target    = target;
  56         par.targinfo  = t->data;
  57         par.hook_mask = hook;
  58
  59         ret = xt_check_target(&par, NFPROTO_IPV4,
  60               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 ipt_entry_target *t)
  69 {
  70         if (t->u.kernel.target->destroy)
  71                 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
  72         module_put(t->u.kernel.target->me);
  73 }
  74
  75 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  76 {
  77         int ret = 0;
  78         if (ipt) {
  79                 if (bind)
  80                         ipt->tcf_bindcnt--;
  81                 ipt->tcf_refcnt--;
  82                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  83                         ipt_destroy_target(ipt->tcfi_t);
  84                         kfree(ipt->tcfi_tname);
  85                         kfree(ipt->tcfi_t);
  86                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
  87                         ret = ACT_P_DELETED;
  88                 }
  89         }
  90         return ret;
  91 }
  92
  93 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  94         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  95         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  96         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  97         [TCA_IPT_TARG]  = { .len = sizeof(struct ipt_entry_target) },
  98 };
  99
 100 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est,
 101                         struct tc_action *a, int ovr, int bind)
 102 {
 103         struct nlattr *tb[TCA_IPT_MAX + 1];
 104         struct tcf_ipt *ipt;
 105         struct tcf_common *pc;
 106         struct ipt_entry_target *td, *t;
 107         char *tname;
 108         int ret = 0, err;
 109         u32 hook = 0;
 110         u32 index = 0;
 111
 112         if (nla == NULL)
 113                 return -EINVAL;
 114
 115         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 116         if (err < 0)
 117                 return err;
 118
 119         if (tb[TCA_IPT_HOOK] == NULL)
 120                 return -EINVAL;
 121         if (tb[TCA_IPT_TARG] == NULL)
 122                 return -EINVAL;
 123
 124         td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 125         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 126                 return -EINVAL;
 127
 128         if (tb[TCA_IPT_INDEX] != NULL)
 129                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 130
 131         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
 132         if (!pc) {
 133                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
 134                                      &ipt_idx_gen, &ipt_hash_info);
 135                 if (unlikely(!pc))
 136                         return -ENOMEM;
 137                 ret = ACT_P_CREATED;
 138         } else {
 139                 if (!ovr) {
 140                         tcf_ipt_release(to_ipt(pc), bind);
 141                         return -EEXIST;
 142                 }
 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         if ((err = ipt_init_target(t, tname, hook)) < 0)
 161                 goto err3;
 162
 163         spin_lock_bh(&ipt->tcf_lock);
 164         if (ret != ACT_P_CREATED) {
 165                 ipt_destroy_target(ipt->tcfi_t);
 166                 kfree(ipt->tcfi_tname);
 167                 kfree(ipt->tcfi_t);
 168         }
 169         ipt->tcfi_tname = tname;
 170         ipt->tcfi_t     = t;
 171         ipt->tcfi_hook  = hook;
 172         spin_unlock_bh(&ipt->tcf_lock);
 173         if (ret == ACT_P_CREATED)
 174                 tcf_hash_insert(pc, &ipt_hash_info);
 175         return ret;
 176
 177 err3:
 178         kfree(t);
 179 err2:
 180         kfree(tname);
 181 err1:
 182         kfree(pc);
 183         return err;
 184 }
 185
 186 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
 187 {
 188         struct tcf_ipt *ipt = a->priv;
 189         return tcf_ipt_release(ipt, bind);
 190 }
 191
 192 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
 193                    struct tcf_result *res)
 194 {
 195         int ret = 0, result = 0;
 196         struct tcf_ipt *ipt = a->priv;
 197         struct xt_target_param par;
 198
 199         if (skb_cloned(skb)) {
 200                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 201                         return TC_ACT_UNSPEC;
 202         }
 203
 204         spin_lock(&ipt->tcf_lock);
 205
 206         ipt->tcf_tm.lastuse = jiffies;
 207         ipt->tcf_bstats.bytes += qdisc_pkt_len(skb);
 208         ipt->tcf_bstats.packets++;
 209
 210         /* yes, we have to worry about both in and out dev
 211          worry later - danger - this API seems to have changed
 212          from earlier kernels */
 213         par.in       = skb->dev;
 214         par.out      = NULL;
 215         par.hooknum  = ipt->tcfi_hook;
 216         par.target   = ipt->tcfi_t->u.kernel.target;
 217         par.targinfo = ipt->tcfi_t->data;
 218         ret = par.target->target(skb, &par);
 219
 220         switch (ret) {
 221         case NF_ACCEPT:
 222                 result = TC_ACT_OK;
 223                 break;
 224         case NF_DROP:
 225                 result = TC_ACT_SHOT;
 226                 ipt->tcf_qstats.drops++;
 227                 break;
 228         case IPT_CONTINUE:
 229                 result = TC_ACT_PIPE;
 230                 break;
 231         default:
 232                 if (net_ratelimit())
 233                         printk("Bogus netfilter code %d assume ACCEPT\n", ret);
 234                 result = TC_POLICE_OK;
 235                 break;
 236         }
 237         spin_unlock(&ipt->tcf_lock);
 238         return result;
 239
 240 }
 241
 242 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 243 {
 244         unsigned char *b = skb_tail_pointer(skb);
 245         struct tcf_ipt *ipt = a->priv;
 246         struct ipt_entry_target *t;
 247         struct tcf_t tm;
 248         struct tc_cnt c;
 249
 250         /* for simple targets kernel size == user size
 251         ** user name = target name
 252         ** for foolproof you need to not assume this
 253         */
 254
 255         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 256         if (unlikely(!t))
 257                 goto nla_put_failure;
 258
 259         c.bindcnt = ipt->tcf_bindcnt - bind;
 260         c.refcnt = ipt->tcf_refcnt - ref;
 261         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 262
 263         NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
 264         NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index);
 265         NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook);
 266         NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
 267         NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname);
 268         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 269         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 270         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 271         NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 272         kfree(t);
 273         return skb->len;
 274
 275 nla_put_failure:
 276         nlmsg_trim(skb, b);
 277         kfree(t);
 278         return -1;
 279 }
 280
 281 static struct tc_action_ops act_ipt_ops = {
 282         .kind           =       "ipt",
 283         .hinfo          =       &ipt_hash_info,
 284         .type           =       TCA_ACT_IPT,
 285         .capab          =       TCA_CAP_NONE,
 286         .owner          =       THIS_MODULE,
 287         .act            =       tcf_ipt,
 288         .dump           =       tcf_ipt_dump,
 289         .cleanup        =       tcf_ipt_cleanup,
 290         .lookup         =       tcf_hash_search,
 291         .init           =       tcf_ipt_init,
 292         .walk           =       tcf_generic_walker
 293 };
 294
 295 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 296 MODULE_DESCRIPTION("Iptables target actions");
 297 MODULE_LICENSE("GPL");
 298
 299 static int __init ipt_init_module(void)
 300 {
 301         return tcf_register_action(&act_ipt_ops);
 302 }
 303
 304 static void __exit ipt_cleanup_module(void)
 305 {
 306         tcf_unregister_action(&act_ipt_ops);
 307 }
 308
 309 module_init(ipt_init_module);
 310 module_exit(ipt_cleanup_module);