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