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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         par.family    = NFPROTO_IPV4;
  59
  60         ret = xt_check_target(&par, 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         struct xt_tgdtor_param par = {
  71                 .target   = t->u.kernel.target,
  72                 .targinfo = t->data,
  73         };
  74         if (par.target->destroy != NULL)
  75                 par.target->destroy(&par);
  76         module_put(par.target->me);
  77 }
  78
  79 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  80 {
  81         int ret = 0;
  82         if (ipt) {
  83                 if (bind)
  84                         ipt->tcf_bindcnt--;
  85                 ipt->tcf_refcnt--;
  86                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  87                         ipt_destroy_target(ipt->tcfi_t);
  88                         kfree(ipt->tcfi_tname);
  89                         kfree(ipt->tcfi_t);
  90                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
  91                         ret = ACT_P_DELETED;
  92                 }
  93         }
  94         return ret;
  95 }
  96
  97 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  98         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  99         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
 100         [TCA_IPT_INDEX] = { .type = NLA_U32 },
 101         [TCA_IPT_TARG]  = { .len = sizeof(struct ipt_entry_target) },
 102 };
 103
 104 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est,
 105                         struct tc_action *a, int ovr, int bind)
 106 {
 107         struct nlattr *tb[TCA_IPT_MAX + 1];
 108         struct tcf_ipt *ipt;
 109         struct tcf_common *pc;
 110         struct ipt_entry_target *td, *t;
 111         char *tname;
 112         int ret = 0, err;
 113         u32 hook = 0;
 114         u32 index = 0;
 115
 116         if (nla == NULL)
 117                 return -EINVAL;
 118
 119         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 120         if (err < 0)
 121                 return err;
 122
 123         if (tb[TCA_IPT_HOOK] == NULL)
 124                 return -EINVAL;
 125         if (tb[TCA_IPT_TARG] == NULL)
 126                 return -EINVAL;
 127
 128         td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 129         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 130                 return -EINVAL;
 131
 132         if (tb[TCA_IPT_INDEX] != NULL)
 133                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 134
 135         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
 136         if (!pc) {
 137                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
 138                                      &ipt_idx_gen, &ipt_hash_info);
 139                 if (IS_ERR(pc))
 140                     return PTR_ERR(pc);
 141                 ret = ACT_P_CREATED;
 142         } else {
 143                 if (!ovr) {
 144                         tcf_ipt_release(to_ipt(pc), bind);
 145                         return -EEXIST;
 146                 }
 147         }
 148         ipt = to_ipt(pc);
 149
 150         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 151
 152         err = -ENOMEM;
 153         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 154         if (unlikely(!tname))
 155                 goto err1;
 156         if (tb[TCA_IPT_TABLE] == NULL ||
 157             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 158                 strcpy(tname, "mangle");
 159
 160         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 161         if (unlikely(!t))
 162                 goto err2;
 163
 164         if ((err = ipt_init_target(t, tname, hook)) < 0)
 165                 goto err3;
 166
 167         spin_lock_bh(&ipt->tcf_lock);
 168         if (ret != ACT_P_CREATED) {
 169                 ipt_destroy_target(ipt->tcfi_t);
 170                 kfree(ipt->tcfi_tname);
 171                 kfree(ipt->tcfi_t);
 172         }
 173         ipt->tcfi_tname = tname;
 174         ipt->tcfi_t     = t;
 175         ipt->tcfi_hook  = hook;
 176         spin_unlock_bh(&ipt->tcf_lock);
 177         if (ret == ACT_P_CREATED)
 178                 tcf_hash_insert(pc, &ipt_hash_info);
 179         return ret;
 180
 181 err3:
 182         kfree(t);
 183 err2:
 184         kfree(tname);
 185 err1:
 186         kfree(pc);
 187         return err;
 188 }
 189
 190 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
 191 {
 192         struct tcf_ipt *ipt = a->priv;
 193         return tcf_ipt_release(ipt, bind);
 194 }
 195
 196 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
 197                    struct tcf_result *res)
 198 {
 199         int ret = 0, result = 0;
 200         struct tcf_ipt *ipt = a->priv;
 201         struct xt_target_param par;
 202
 203         if (skb_cloned(skb)) {
 204                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 205                         return TC_ACT_UNSPEC;
 206         }
 207
 208         spin_lock(&ipt->tcf_lock);
 209
 210         ipt->tcf_tm.lastuse = jiffies;
 211         ipt->tcf_bstats.bytes += qdisc_pkt_len(skb);
 212         ipt->tcf_bstats.packets++;
 213
 214         /* yes, we have to worry about both in and out dev
 215          worry later - danger - this API seems to have changed
 216          from earlier kernels */
 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 IPT_CONTINUE:
 233                 result = TC_ACT_PIPE;
 234                 break;
 235         default:
 236                 if (net_ratelimit())
 237                         printk("Bogus netfilter code %d assume ACCEPT\n", 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 ipt_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         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         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 273         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 274         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 275         NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 276         kfree(t);
 277         return skb->len;
 278
 279 nla_put_failure:
 280         nlmsg_trim(skb, b);
 281         kfree(t);
 282         return -1;
 283 }
 284
 285 static struct tc_action_ops act_ipt_ops = {
 286         .kind           =       "ipt",
 287         .hinfo          =       &ipt_hash_info,
 288         .type           =       TCA_ACT_IPT,
 289         .capab          =       TCA_CAP_NONE,
 290         .owner          =       THIS_MODULE,
 291         .act            =       tcf_ipt,
 292         .dump           =       tcf_ipt_dump,
 293         .cleanup        =       tcf_ipt_cleanup,
 294         .lookup         =       tcf_hash_search,
 295         .init           =       tcf_ipt_init,
 296         .walk           =       tcf_generic_walker
 297 };
 298
 299 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 300 MODULE_DESCRIPTION("Iptables target actions");
 301 MODULE_LICENSE("GPL");
 302
 303 static int __init ipt_init_module(void)
 304 {
 305         return tcf_register_action(&act_ipt_ops);
 306 }
 307
 308 static void __exit ipt_cleanup_module(void)
 309 {
 310         tcf_unregister_action(&act_ipt_ops);
 311 }
 312
 313 module_init(ipt_init_module);
 314 module_exit(ipt_cleanup_module);