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/sched.h>
  20 #include <linux/string.h>
  21 #include <linux/mm.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/in.h>
  25 #include <linux/errno.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/rtnetlink.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/kmod.h>
  34 #include <net/sock.h>
  35 #include <net/pkt_sched.h>
  36 #include <linux/tc_act/tc_ipt.h>
  37 #include <net/tc_act/tc_ipt.h>
  38
  39 #include <linux/netfilter_ipv4/ip_tables.h>
  40
  41
  42 #define IPT_TAB_MASK     15
  43 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
  44 static u32 ipt_idx_gen;
  45 static DEFINE_RWLOCK(ipt_lock);
  46
  47 static struct tcf_hashinfo ipt_hash_info = {
  48         .htab   =       tcf_ipt_ht,
  49         .hmask  =       IPT_TAB_MASK,
  50         .lock   =       &ipt_lock,
  51 };
  52
  53 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
  54 {
  55         struct ipt_target *target;
  56         int ret = 0;
  57
  58         target = xt_request_find_target(AF_INET, t->u.user.name,
  59                                         t->u.user.revision);
  60         if (!target)
  61                 return -ENOENT;
  62
  63         t->u.kernel.target = target;
  64
  65         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
  66                               table, hook, 0, 0);
  67         if (ret) {
  68                 module_put(t->u.kernel.target->me);
  69                 return ret;
  70         }
  71         if (t->u.kernel.target->checkentry
  72             && !t->u.kernel.target->checkentry(table, NULL,
  73                                                t->u.kernel.target, t->data,
  74                                                hook)) {
  75                 module_put(t->u.kernel.target->me);
  76                 ret = -EINVAL;
  77         }
  78
  79         return ret;
  80 }
  81
  82 static void ipt_destroy_target(struct ipt_entry_target *t)
  83 {
  84         if (t->u.kernel.target->destroy)
  85                 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
  86         module_put(t->u.kernel.target->me);
  87 }
  88
  89 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
  90 {
  91         int ret = 0;
  92         if (ipt) {
  93                 if (bind)
  94                         ipt->tcf_bindcnt--;
  95                 ipt->tcf_refcnt--;
  96                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
  97                         ipt_destroy_target(ipt->tcfi_t);
  98                         kfree(ipt->tcfi_tname);
  99                         kfree(ipt->tcfi_t);
 100                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
 101                         ret = ACT_P_DELETED;
 102                 }
 103         }
 104         return ret;
 105 }
 106
 107 static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est,
 108                         struct tc_action *a, int ovr, int bind)
 109 {
 110         struct rtattr *tb[TCA_IPT_MAX];
 111         struct tcf_ipt *ipt;
 112         struct tcf_common *pc;
 113         struct ipt_entry_target *td, *t;
 114         char *tname;
 115         int ret = 0, err;
 116         u32 hook = 0;
 117         u32 index = 0;
 118
 119         if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0)
 120                 return -EINVAL;
 121
 122         if (tb[TCA_IPT_HOOK-1] == NULL ||
 123             RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32))
 124                 return -EINVAL;
 125         if (tb[TCA_IPT_TARG-1] == NULL ||
 126             RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t))
 127                 return -EINVAL;
 128         td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]);
 129         if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size)
 130                 return -EINVAL;
 131
 132         if (tb[TCA_IPT_INDEX-1] != NULL &&
 133             RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32))
 134                 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]);
 135
 136         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
 137         if (!pc) {
 138                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
 139                                      &ipt_idx_gen, &ipt_hash_info);
 140                 if (unlikely(!pc))
 141                         return -ENOMEM;
 142                 ret = ACT_P_CREATED;
 143         } else {
 144                 if (!ovr) {
 145                         tcf_ipt_release(to_ipt(pc), bind);
 146                         return -EEXIST;
 147                 }
 148         }
 149         ipt = to_ipt(pc);
 150
 151         hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]);
 152
 153         err = -ENOMEM;
 154         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 155         if (unlikely(!tname))
 156                 goto err1;
 157         if (tb[TCA_IPT_TABLE - 1] == NULL ||
 158             rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ)
 159                 strcpy(tname, "mangle");
 160
 161         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 162         if (unlikely(!t))
 163                 goto err2;
 164
 165         if ((err = ipt_init_target(t, tname, hook)) < 0)
 166                 goto err3;
 167
 168         spin_lock_bh(&ipt->tcf_lock);
 169         if (ret != ACT_P_CREATED) {
 170                 ipt_destroy_target(ipt->tcfi_t);
 171                 kfree(ipt->tcfi_tname);
 172                 kfree(ipt->tcfi_t);
 173         }
 174         ipt->tcfi_tname = tname;
 175         ipt->tcfi_t     = t;
 176         ipt->tcfi_hook  = hook;
 177         spin_unlock_bh(&ipt->tcf_lock);
 178         if (ret == ACT_P_CREATED)
 179                 tcf_hash_insert(pc, &ipt_hash_info);
 180         return ret;
 181
 182 err3:
 183         kfree(t);
 184 err2:
 185         kfree(tname);
 186 err1:
 187         kfree(pc);
 188         return err;
 189 }
 190
 191 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
 192 {
 193         struct tcf_ipt *ipt = a->priv;
 194         return tcf_ipt_release(ipt, bind);
 195 }
 196
 197 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
 198                    struct tcf_result *res)
 199 {
 200         int ret = 0, result = 0;
 201         struct tcf_ipt *ipt = a->priv;
 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 += skb->len;
 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
 218         /* iptables targets take a double skb pointer in case the skb
 219          * needs to be replaced. We don't own the skb, so this must not
 220          * happen. The pskb_expand_head above should make sure of this */
 221         ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL,
 222                                                    ipt->tcfi_hook,
 223                                                    ipt->tcfi_t->u.kernel.target,
 224                                                    ipt->tcfi_t->data);
 225         switch (ret) {
 226         case NF_ACCEPT:
 227                 result = TC_ACT_OK;
 228                 break;
 229         case NF_DROP:
 230                 result = TC_ACT_SHOT;
 231                 ipt->tcf_qstats.drops++;
 232                 break;
 233         case IPT_CONTINUE:
 234                 result = TC_ACT_PIPE;
 235                 break;
 236         default:
 237                 if (net_ratelimit())
 238                         printk("Bogus netfilter code %d assume ACCEPT\n", ret);
 239                 result = TC_POLICE_OK;
 240                 break;
 241         }
 242         spin_unlock(&ipt->tcf_lock);
 243         return result;
 244
 245 }
 246
 247 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 248 {
 249         unsigned char *b = skb->tail;
 250         struct tcf_ipt *ipt = a->priv;
 251         struct ipt_entry_target *t;
 252         struct tcf_t tm;
 253         struct tc_cnt c;
 254
 255         /* for simple targets kernel size == user size
 256         ** user name = target name
 257         ** for foolproof you need to not assume this
 258         */
 259
 260         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 261         if (unlikely(!t))
 262                 goto rtattr_failure;
 263
 264         c.bindcnt = ipt->tcf_bindcnt - bind;
 265         c.refcnt = ipt->tcf_refcnt - ref;
 266         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 267
 268         RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
 269         RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index);
 270         RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook);
 271         RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
 272         RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, ipt->tcfi_tname);
 273         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 274         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 275         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 276         RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 277         kfree(t);
 278         return skb->len;
 279
 280 rtattr_failure:
 281         skb_trim(skb, b - skb->data);
 282         kfree(t);
 283         return -1;
 284 }
 285
 286 static struct tc_action_ops act_ipt_ops = {
 287         .kind           =       "ipt",
 288         .hinfo          =       &ipt_hash_info,
 289         .type           =       TCA_ACT_IPT,
 290         .capab          =       TCA_CAP_NONE,
 291         .owner          =       THIS_MODULE,
 292         .act            =       tcf_ipt,
 293         .dump           =       tcf_ipt_dump,
 294         .cleanup        =       tcf_ipt_cleanup,
 295         .lookup         =       tcf_hash_search,
 296         .init           =       tcf_ipt_init,
 297         .walk           =       tcf_generic_walker
 298 };
 299
 300 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 301 MODULE_DESCRIPTION("Iptables target actions");
 302 MODULE_LICENSE("GPL");
 303
 304 static int __init ipt_init_module(void)
 305 {
 306         return tcf_register_action(&act_ipt_ops);
 307 }
 308
 309 static void __exit ipt_cleanup_module(void)
 310 {
 311         tcf_unregister_action(&act_ipt_ops);
 312 }
 313
 314 module_init(ipt_init_module);
 315 module_exit(ipt_cleanup_module);