net/sched/act_ipt.c

   1 /*
   2  * net/sched/act_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 (2002-13)
  12  */
  13
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/rtnetlink.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <net/netlink.h>
  24 #include <net/pkt_sched.h>
  25 #include <linux/tc_act/tc_ipt.h>
  26 #include <net/tc_act/tc_ipt.h>
  27
  28 #include <linux/netfilter_ipv4/ip_tables.h>
  29
  30
  31 #define IPT_TAB_MASK     15
  32
  33 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
  34 {
  35         struct xt_tgchk_param par;
  36         struct xt_target *target;
  37         int ret = 0;
  38
  39         target = xt_request_find_target(AF_INET, t->u.user.name,
  40                                         t->u.user.revision);
  41         if (IS_ERR(target))
  42                 return PTR_ERR(target);
  43
  44         t->u.kernel.target = target;
  45         par.table     = table;
  46         par.entryinfo = NULL;
  47         par.target    = target;
  48         par.targinfo  = t->data;
  49         par.hook_mask = hook;
  50         par.family    = NFPROTO_IPV4;
  51
  52         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  53         if (ret < 0) {
  54                 module_put(t->u.kernel.target->me);
  55                 return ret;
  56         }
  57         return 0;
  58 }
  59
  60 static void ipt_destroy_target(struct xt_entry_target *t)
  61 {
  62         struct xt_tgdtor_param par = {
  63                 .target   = t->u.kernel.target,
  64                 .targinfo = t->data,
  65         };
  66         if (par.target->destroy != NULL)
  67                 par.target->destroy(&par);
  68         module_put(par.target->me);
  69 }
  70
  71 static void tcf_ipt_release(struct tc_action *a, int bind)
  72 {
  73         struct tcf_ipt *ipt = to_ipt(a);
  74         ipt_destroy_target(ipt->tcfi_t);
  75         kfree(ipt->tcfi_tname);
  76         kfree(ipt->tcfi_t);
  77 }
  78
  79 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  80         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  81         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  82         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  83         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  84 };
  85
  86 static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est,
  87                         struct tc_action *a, int ovr, int bind)
  88 {
  89         struct nlattr *tb[TCA_IPT_MAX + 1];
  90         struct tcf_ipt *ipt;
  91         struct xt_entry_target *td, *t;
  92         char *tname;
  93         int ret = 0, err;
  94         u32 hook = 0;
  95         u32 index = 0;
  96
  97         if (nla == NULL)
  98                 return -EINVAL;
  99
 100         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 101         if (err < 0)
 102                 return err;
 103
 104         if (tb[TCA_IPT_HOOK] == NULL)
 105                 return -EINVAL;
 106         if (tb[TCA_IPT_TARG] == NULL)
 107                 return -EINVAL;
 108
 109         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 110         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 111                 return -EINVAL;
 112
 113         if (tb[TCA_IPT_INDEX] != NULL)
 114                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 115
 116         if (!tcf_hash_check(index, a, bind) ) {
 117                 ret = tcf_hash_create(index, est, a, sizeof(*ipt), bind, false);
 118                 if (ret)
 119                         return ret;
 120                 ret = ACT_P_CREATED;
 121         } else {
 122                 if (bind)/* dont override defaults */
 123                         return 0;
 124                 tcf_hash_release(a, bind);
 125
 126                 if (!ovr)
 127                         return -EEXIST;
 128         }
 129         ipt = to_ipt(a);
 130
 131         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 132
 133         err = -ENOMEM;
 134         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 135         if (unlikely(!tname))
 136                 goto err1;
 137         if (tb[TCA_IPT_TABLE] == NULL ||
 138             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 139                 strcpy(tname, "mangle");
 140
 141         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 142         if (unlikely(!t))
 143                 goto err2;
 144
 145         err = ipt_init_target(t, tname, hook);
 146         if (err < 0)
 147                 goto err3;
 148
 149         spin_lock_bh(&ipt->tcf_lock);
 150         if (ret != ACT_P_CREATED) {
 151                 ipt_destroy_target(ipt->tcfi_t);
 152                 kfree(ipt->tcfi_tname);
 153                 kfree(ipt->tcfi_t);
 154         }
 155         ipt->tcfi_tname = tname;
 156         ipt->tcfi_t     = t;
 157         ipt->tcfi_hook  = hook;
 158         spin_unlock_bh(&ipt->tcf_lock);
 159         if (ret == ACT_P_CREATED)
 160                 tcf_hash_insert(a);
 161         return ret;
 162
 163 err3:
 164         kfree(t);
 165 err2:
 166         kfree(tname);
 167 err1:
 168         if (ret == ACT_P_CREATED)
 169                 tcf_hash_cleanup(a, est);
 170         return err;
 171 }
 172
 173 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
 174                    struct tcf_result *res)
 175 {
 176         int ret = 0, result = 0;
 177         struct tcf_ipt *ipt = a->priv;
 178         struct xt_action_param par;
 179
 180         if (skb_unclone(skb, GFP_ATOMIC))
 181                 return TC_ACT_UNSPEC;
 182
 183         spin_lock(&ipt->tcf_lock);
 184
 185         ipt->tcf_tm.lastuse = jiffies;
 186         bstats_update(&ipt->tcf_bstats, skb);
 187
 188         /* yes, we have to worry about both in and out dev
 189          * worry later - danger - this API seems to have changed
 190          * from earlier kernels
 191          */
 192         par.net      = dev_net(skb->dev);
 193         par.in       = skb->dev;
 194         par.out      = NULL;
 195         par.hooknum  = ipt->tcfi_hook;
 196         par.target   = ipt->tcfi_t->u.kernel.target;
 197         par.targinfo = ipt->tcfi_t->data;
 198         ret = par.target->target(skb, &par);
 199
 200         switch (ret) {
 201         case NF_ACCEPT:
 202                 result = TC_ACT_OK;
 203                 break;
 204         case NF_DROP:
 205                 result = TC_ACT_SHOT;
 206                 ipt->tcf_qstats.drops++;
 207                 break;
 208         case XT_CONTINUE:
 209                 result = TC_ACT_PIPE;
 210                 break;
 211         default:
 212                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 213                                        ret);
 214                 result = TC_POLICE_OK;
 215                 break;
 216         }
 217         spin_unlock(&ipt->tcf_lock);
 218         return result;
 219
 220 }
 221
 222 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 223 {
 224         unsigned char *b = skb_tail_pointer(skb);
 225         struct tcf_ipt *ipt = a->priv;
 226         struct xt_entry_target *t;
 227         struct tcf_t tm;
 228         struct tc_cnt c;
 229
 230         /* for simple targets kernel size == user size
 231          * user name = target name
 232          * for foolproof you need to not assume this
 233          */
 234
 235         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 236         if (unlikely(!t))
 237                 goto nla_put_failure;
 238
 239         c.bindcnt = ipt->tcf_bindcnt - bind;
 240         c.refcnt = ipt->tcf_refcnt - ref;
 241         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 242
 243         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 244             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 245             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 246             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 247             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 248                 goto nla_put_failure;
 249         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 250         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 251         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 252         if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
 253                 goto nla_put_failure;
 254         kfree(t);
 255         return skb->len;
 256
 257 nla_put_failure:
 258         nlmsg_trim(skb, b);
 259         kfree(t);
 260         return -1;
 261 }
 262
 263 static struct tc_action_ops act_ipt_ops = {
 264         .kind           =       "ipt",
 265         .type           =       TCA_ACT_IPT,
 266         .owner          =       THIS_MODULE,
 267         .act            =       tcf_ipt,
 268         .dump           =       tcf_ipt_dump,
 269         .cleanup        =       tcf_ipt_release,
 270         .init           =       tcf_ipt_init,
 271 };
 272
 273 static struct tc_action_ops act_xt_ops = {
 274         .kind           =       "xt",
 275         .type           =       TCA_ACT_XT,
 276         .owner          =       THIS_MODULE,
 277         .act            =       tcf_ipt,
 278         .dump           =       tcf_ipt_dump,
 279         .cleanup        =       tcf_ipt_release,
 280         .init           =       tcf_ipt_init,
 281 };
 282
 283 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 284 MODULE_DESCRIPTION("Iptables target actions");
 285 MODULE_LICENSE("GPL");
 286 MODULE_ALIAS("act_xt");
 287
 288 static int __init ipt_init_module(void)
 289 {
 290         int ret1, ret2;
 291
 292         ret1 = tcf_register_action(&act_xt_ops, IPT_TAB_MASK);
 293         if (ret1 < 0)
 294                 printk("Failed to load xt action\n");
 295         ret2 = tcf_register_action(&act_ipt_ops, IPT_TAB_MASK);
 296         if (ret2 < 0)
 297                 printk("Failed to load ipt action\n");
 298
 299         if (ret1 < 0 && ret2 < 0) {
 300                 return ret1;
 301         } else
 302                 return 0;
 303 }
 304
 305 static void __exit ipt_cleanup_module(void)
 306 {
 307         tcf_unregister_action(&act_xt_ops);
 308         tcf_unregister_action(&act_ipt_ops);
 309 }
 310
 311 module_init(ipt_init_module);
 312 module_exit(ipt_cleanup_module);