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