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 <asm/uaccess.h>
  15 #include <asm/system.h>
  16 #include <asm/bitops.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/socket.h>
  22 #include <linux/sockios.h>
  23 #include <linux/in.h>
  24 #include <linux/errno.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/rtnetlink.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/kmod.h>
  33 #include <net/sock.h>
  34 #include <net/pkt_sched.h>
  35 #include <linux/tc_act/tc_ipt.h>
  36 #include <net/tc_act/tc_ipt.h>
  37
  38 #include <linux/netfilter_ipv4/ip_tables.h>
  39
  40
  41 #define IPT_TAB_MASK     15
  42 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
  43 static u32 ipt_idx_gen;
  44 static DEFINE_RWLOCK(ipt_lock);
  45
  46 static struct tcf_hashinfo ipt_hash_info = {
  47         .htab   =       tcf_ipt_ht,
  48         .hmask  =       IPT_TAB_MASK,
  49         .lock   =       &ipt_lock,
  50 };
  51
  52 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
  53 {
  54         struct xt_target *target;
  55         int ret = 0;
  56
  57         target = xt_request_find_target(AF_INET, t->u.user.name,
  58                                         t->u.user.revision);
  59         if (!target)
  60                 return -ENOENT;
  61
  62         t->u.kernel.target = target;
  63
  64         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
  65                               table, hook, 0, 0);
  66         if (ret) {
  67                 module_put(t->u.kernel.target->me);
  68                 return ret;
  69         }
  70         if (t->u.kernel.target->checkentry
  71             && !t->u.kernel.target->checkentry(table, NULL,
  72                                                t->u.kernel.target, t->data,
  73                                                hook)) {
  74                 module_put(t->u.kernel.target->me);
  75                 ret = -EINVAL;
  76         }
  77
  78         return ret;
  79 }
  80
  81 static void ipt_destroy_target(struct ipt_entry_target *t)
  82 {
  83         if (t->u.kernel.target->destroy)
  84                 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
  85         module_put(t->u.kernel.target->me);
  86 }
  87
  88 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  89 {
  90         int ret = 0;
  91         if (ipt) {
  92                 if (bind)
  93                         ipt->tcf_bindcnt--;
  94                 ipt->tcf_refcnt--;
  95                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  96                         ipt_destroy_target(ipt->tcfi_t);
  97                         kfree(ipt->tcfi_tname);
  98                         kfree(ipt->tcfi_t);
  99                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
 100                         ret = ACT_P_DELETED;
 101                 }
 102         }
 103         return ret;
 104 }
 105
 106 static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est,
 107                         struct tc_action *a, int ovr, int bind)
 108 {
 109         struct rtattr *tb[TCA_IPT_MAX];
 110         struct tcf_ipt *ipt;
 111         struct tcf_common *pc;
 112         struct ipt_entry_target *td, *t;
 113         char *tname;
 114         int ret = 0, err;
 115         u32 hook = 0;
 116         u32 index = 0;
 117
 118         if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0)
 119                 return -EINVAL;
 120
 121         if (tb[TCA_IPT_HOOK-1] == NULL ||
 122             RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32))
 123                 return -EINVAL;
 124         if (tb[TCA_IPT_TARG-1] == NULL ||
 125             RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t))
 126                 return -EINVAL;
 127         td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]);
 128         if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size)
 129                 return -EINVAL;
 130
 131         if (tb[TCA_IPT_INDEX-1] != NULL &&
 132             RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32))
 133                 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]);
 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 (unlikely(!pc))
 140                         return -ENOMEM;
 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 = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]);
 151
 152         err = -ENOMEM;
 153         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 154         if (unlikely(!tname))
 155                 goto err1;
 156         if (tb[TCA_IPT_TABLE - 1] == NULL ||
 157             rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], 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
 202         if (skb_cloned(skb)) {
 203                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 204                         return TC_ACT_UNSPEC;
 205         }
 206
 207         spin_lock(&ipt->tcf_lock);
 208
 209         ipt->tcf_tm.lastuse = jiffies;
 210         ipt->tcf_bstats.bytes += skb->len;
 211         ipt->tcf_bstats.packets++;
 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         /* iptables targets take a double skb pointer in case the skb
 218          * needs to be replaced. We don't own the skb, so this must not
 219          * happen. The pskb_expand_head above should make sure of this */
 220         ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL,
 221                                                    ipt->tcfi_hook,
 222                                                    ipt->tcfi_t->u.kernel.target,
 223                                                    ipt->tcfi_t->data);
 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;
 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 rtattr_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         RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
 268         RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index);
 269         RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook);
 270         RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
 271         RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, 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         RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 276         kfree(t);
 277         return skb->len;
 278
 279 rtattr_failure:
 280         skb_trim(skb, b - skb->data);
 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);