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