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/config.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/string.h>
  22 #include <linux/mm.h>
  23 #include <linux/socket.h>
  24 #include <linux/sockios.h>
  25 #include <linux/in.h>
  26 #include <linux/errno.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/rtnetlink.h>
  31 #include <linux/module.h>
  32 #include <linux/init.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/kmod.h>
  35 #include <net/sock.h>
  36 #include <net/pkt_sched.h>
  37 #include <linux/tc_act/tc_ipt.h>
  38 #include <net/tc_act/tc_ipt.h>
  39
  40 #include <linux/netfilter_ipv4/ip_tables.h>
  41
  42 /* use generic hash table */
  43 #define MY_TAB_SIZE     16
  44 #define MY_TAB_MASK     15
  45
  46 static u32 idx_gen;
  47 static struct tcf_ipt *tcf_ipt_ht[MY_TAB_SIZE];
  48 /* ipt hash table lock */
  49 static DEFINE_RWLOCK(ipt_lock);
  50
  51 /* ovewrride the defaults */
  52 #define tcf_st          tcf_ipt
  53 #define tcf_t_lock      ipt_lock
  54 #define tcf_ht          tcf_ipt_ht
  55
  56 #define CONFIG_NET_ACT_INIT
  57 #include <net/pkt_act.h>
  58
  59 static int
  60 ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
  61 {
  62         struct ipt_target *target;
  63         int ret = 0;
  64
  65         target = xt_find_target(AF_INET, t->u.user.name, t->u.user.revision);
  66         if (!target)
  67                 return -ENOENT;
  68
  69         DPRINTK("ipt_init_target: found %s\n", target->name);
  70         t->u.kernel.target = target;
  71
  72         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
  73                               table, hook, 0, 0);
  74         if (ret)
  75                 return ret;
  76
  77         if (t->u.kernel.target->checkentry
  78             && !t->u.kernel.target->checkentry(table, NULL,
  79                                                t->u.kernel.target, t->data,
  80                                                t->u.target_size - sizeof(*t),
  81                                                hook)) {
  82                 DPRINTK("ipt_init_target: check failed for `%s'.\n",
  83                         t->u.kernel.target->name);
  84                 module_put(t->u.kernel.target->me);
  85                 ret = -EINVAL;
  86         }
  87
  88         return ret;
  89 }
  90
  91 static void
  92 ipt_destroy_target(struct ipt_entry_target *t)
  93 {
  94         if (t->u.kernel.target->destroy)
  95                 t->u.kernel.target->destroy(t->u.kernel.target, t->data,
  96                                             t->u.target_size - sizeof(*t));
  97         module_put(t->u.kernel.target->me);
  98 }
  99
 100 static int
 101 tcf_ipt_release(struct tcf_ipt *p, int bind)
 102 {
 103         int ret = 0;
 104         if (p) {
 105                 if (bind)
 106                         p->bindcnt--;
 107                 p->refcnt--;
 108                 if (p->bindcnt <= 0 && p->refcnt <= 0) {
 109                         ipt_destroy_target(p->t);
 110                         kfree(p->tname);
 111                         kfree(p->t);
 112                         tcf_hash_destroy(p);
 113                         ret = ACT_P_DELETED;
 114                 }
 115         }
 116         return ret;
 117 }
 118
 119 static int
 120 tcf_ipt_init(struct rtattr *rta, struct rtattr *est, struct tc_action *a,
 121              int ovr, int bind)
 122 {
 123         struct rtattr *tb[TCA_IPT_MAX];
 124         struct tcf_ipt *p;
 125         struct ipt_entry_target *td, *t;
 126         char *tname;
 127         int ret = 0, err;
 128         u32 hook = 0;
 129         u32 index = 0;
 130
 131         if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0)
 132                 return -EINVAL;
 133
 134         if (tb[TCA_IPT_HOOK-1] == NULL ||
 135             RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32))
 136                 return -EINVAL;
 137         if (tb[TCA_IPT_TARG-1] == NULL ||
 138             RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t))
 139                 return -EINVAL;
 140         td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]);
 141         if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size)
 142                 return -EINVAL;
 143
 144         if (tb[TCA_IPT_INDEX-1] != NULL &&
 145             RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32))
 146                 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]);
 147
 148         p = tcf_hash_check(index, a, ovr, bind);
 149         if (p == NULL) {
 150                 p = tcf_hash_create(index, est, a, sizeof(*p), ovr, bind);
 151                 if (p == NULL)
 152                         return -ENOMEM;
 153                 ret = ACT_P_CREATED;
 154         } else {
 155                 if (!ovr) {
 156                         tcf_ipt_release(p, bind);
 157                         return -EEXIST;
 158                 }
 159         }
 160
 161         hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]);
 162
 163         err = -ENOMEM;
 164         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 165         if (tname == NULL)
 166                 goto err1;
 167         if (tb[TCA_IPT_TABLE - 1] == NULL ||
 168             rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ)
 169                 strcpy(tname, "mangle");
 170
 171         t = kmalloc(td->u.target_size, GFP_KERNEL);
 172         if (t == NULL)
 173                 goto err2;
 174         memcpy(t, td, td->u.target_size);
 175
 176         if ((err = ipt_init_target(t, tname, hook)) < 0)
 177                 goto err3;
 178
 179         spin_lock_bh(&p->lock);
 180         if (ret != ACT_P_CREATED) {
 181                 ipt_destroy_target(p->t);
 182                 kfree(p->tname);
 183                 kfree(p->t);
 184         }
 185         p->tname = tname;
 186         p->t     = t;
 187         p->hook  = hook;
 188         spin_unlock_bh(&p->lock);
 189         if (ret == ACT_P_CREATED)
 190                 tcf_hash_insert(p);
 191         return ret;
 192
 193 err3:
 194         kfree(t);
 195 err2:
 196         kfree(tname);
 197 err1:
 198         kfree(p);
 199         return err;
 200 }
 201
 202 static int
 203 tcf_ipt_cleanup(struct tc_action *a, int bind)
 204 {
 205         struct tcf_ipt *p = PRIV(a, ipt);
 206         return tcf_ipt_release(p, bind);
 207 }
 208
 209 static int
 210 tcf_ipt(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
 211 {
 212         int ret = 0, result = 0;
 213         struct tcf_ipt *p = PRIV(a, ipt);
 214
 215         if (skb_cloned(skb)) {
 216                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 217                         return TC_ACT_UNSPEC;
 218         }
 219
 220         spin_lock(&p->lock);
 221
 222         p->tm.lastuse = jiffies;
 223         p->bstats.bytes += skb->len;
 224         p->bstats.packets++;
 225
 226         /* yes, we have to worry about both in and out dev
 227          worry later - danger - this API seems to have changed
 228          from earlier kernels */
 229
 230         /* iptables targets take a double skb pointer in case the skb
 231          * needs to be replaced. We don't own the skb, so this must not
 232          * happen. The pskb_expand_head above should make sure of this */
 233         ret = p->t->u.kernel.target->target(&skb, skb->dev, NULL, p->hook,
 234                                             p->t->u.kernel.target, p->t->data,
 235                                             NULL);
 236         switch (ret) {
 237         case NF_ACCEPT:
 238                 result = TC_ACT_OK;
 239                 break;
 240         case NF_DROP:
 241                 result = TC_ACT_SHOT;
 242                 p->qstats.drops++;
 243                 break;
 244         case IPT_CONTINUE:
 245                 result = TC_ACT_PIPE;
 246                 break;
 247         default:
 248                 if (net_ratelimit())
 249                         printk("Bogus netfilter code %d assume ACCEPT\n", ret);
 250                 result = TC_POLICE_OK;
 251                 break;
 252         }
 253         spin_unlock(&p->lock);
 254         return result;
 255
 256 }
 257
 258 static int
 259 tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 260 {
 261         struct ipt_entry_target *t;
 262         struct tcf_t tm;
 263         struct tc_cnt c;
 264         unsigned char *b = skb->tail;
 265         struct tcf_ipt *p = PRIV(a, ipt);
 266
 267         /* for simple targets kernel size == user size
 268         ** user name = target name
 269         ** for foolproof you need to not assume this
 270         */
 271
 272         t = kmalloc(p->t->u.user.target_size, GFP_ATOMIC);
 273         if (t == NULL)
 274                 goto rtattr_failure;
 275
 276         c.bindcnt = p->bindcnt - bind;
 277         c.refcnt = p->refcnt - ref;
 278         memcpy(t, p->t, p->t->u.user.target_size);
 279         strcpy(t->u.user.name, p->t->u.kernel.target->name);
 280
 281         DPRINTK("\ttcf_ipt_dump tablename %s length %d\n", p->tname,
 282                 strlen(p->tname));
 283         DPRINTK("\tdump target name %s size %d size user %d "
 284                 "data[0] %x data[1] %x\n", p->t->u.kernel.target->name,
 285                 p->t->u.target_size, p->t->u.user.target_size,
 286                 p->t->data[0], p->t->data[1]);
 287         RTA_PUT(skb, TCA_IPT_TARG, p->t->u.user.target_size, t);
 288         RTA_PUT(skb, TCA_IPT_INDEX, 4, &p->index);
 289         RTA_PUT(skb, TCA_IPT_HOOK, 4, &p->hook);
 290         RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
 291         RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, p->tname);
 292         tm.install = jiffies_to_clock_t(jiffies - p->tm.install);
 293         tm.lastuse = jiffies_to_clock_t(jiffies - p->tm.lastuse);
 294         tm.expires = jiffies_to_clock_t(p->tm.expires);
 295         RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
 296         kfree(t);
 297         return skb->len;
 298
 299       rtattr_failure:
 300         skb_trim(skb, b - skb->data);
 301         kfree(t);
 302         return -1;
 303 }
 304
 305 static struct tc_action_ops act_ipt_ops = {
 306         .kind           =       "ipt",
 307         .type           =       TCA_ACT_IPT,
 308         .capab          =       TCA_CAP_NONE,
 309         .owner          =       THIS_MODULE,
 310         .act            =       tcf_ipt,
 311         .dump           =       tcf_ipt_dump,
 312         .cleanup        =       tcf_ipt_cleanup,
 313         .lookup         =       tcf_hash_search,
 314         .init           =       tcf_ipt_init,
 315         .walk           =       tcf_generic_walker
 316 };
 317
 318 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 319 MODULE_DESCRIPTION("Iptables target actions");
 320 MODULE_LICENSE("GPL");
 321
 322 static int __init
 323 ipt_init_module(void)
 324 {
 325         return tcf_register_action(&act_ipt_ops);
 326 }
 327
 328 static void __exit
 329 ipt_cleanup_module(void)
 330 {
 331         tcf_unregister_action(&act_ipt_ops);
 332 }
 333
 334 module_init(ipt_init_module);
 335 module_exit(ipt_cleanup_module);