LXR linux/net/netfilter/xt

   1/*
   2 * (C) 2013 Astaro GmbH & Co KG
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/skbuff.h>
  11#include <net/netfilter/nf_conntrack.h>
  12#include <net/netfilter/nf_conntrack_ecache.h>
  13#include <net/netfilter/nf_conntrack_labels.h>
  14#include <linux/netfilter/x_tables.h>
  15
  16MODULE_LICENSE("GPL");
  17MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
  18MODULE_DESCRIPTION("Xtables: add/match connection trackling labels");
  19MODULE_ALIAS("ipt_connlabel");
  20MODULE_ALIAS("ip6t_connlabel");
  21
  22static bool
  23connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par)
  24{
  25        const struct xt_connlabel_mtinfo *info = par->matchinfo;
  26        enum ip_conntrack_info ctinfo;
  27        struct nf_conn_labels *labels;
  28        struct nf_conn *ct;
  29        bool invert = info->options & XT_CONNLABEL_OP_INVERT;
  30
  31        ct = nf_ct_get(skb, &ctinfo);
  32        if (ct == NULL || nf_ct_is_untracked(ct))
  33                return invert;
  34
  35        labels = nf_ct_labels_find(ct);
  36        if (!labels)
  37                return invert;
  38
  39        if (test_bit(info->bit, labels->bits))
  40                return !invert;
  41
  42        if (info->options & XT_CONNLABEL_OP_SET) {
  43                if (!test_and_set_bit(info->bit, labels->bits))
  44                        nf_conntrack_event_cache(IPCT_LABEL, ct);
  45
  46                return !invert;
  47        }
  48
  49        return invert;
  50}
  51
  52static int connlabel_mt_check(const struct xt_mtchk_param *par)
  53{
  54        const int options = XT_CONNLABEL_OP_INVERT |
  55                            XT_CONNLABEL_OP_SET;
  56        struct xt_connlabel_mtinfo *info = par->matchinfo;
  57        int ret;
  58
  59        if (info->options & ~options) {
  60                pr_err("Unknown options in mask %x\n", info->options);
  61                return -EINVAL;
  62        }
  63
  64        ret = nf_ct_l3proto_try_module_get(par->family);
  65        if (ret < 0) {
  66                pr_info("cannot load conntrack support for proto=%u\n",
  67                                                        par->family);
  68                return ret;
  69        }
  70
  71        ret = nf_connlabels_get(par->net, info->bit);
  72        if (ret < 0)
  73                nf_ct_l3proto_module_put(par->family);
  74        return ret;
  75}
  76
  77static void connlabel_mt_destroy(const struct xt_mtdtor_param *par)
  78{
  79        nf_connlabels_put(par->net);
  80        nf_ct_l3proto_module_put(par->family);
  81}
  82
  83static struct xt_match connlabels_mt_reg __read_mostly = {
  84        .name           = "connlabel",
  85        .family         = NFPROTO_UNSPEC,
  86        .checkentry     = connlabel_mt_check,
  87        .match          = connlabel_mt,
  88        .matchsize      = sizeof(struct xt_connlabel_mtinfo),
  89        .destroy        = connlabel_mt_destroy,
  90        .me             = THIS_MODULE,
  91};
  92
  93static int __init connlabel_mt_init(void)
  94{
  95        return xt_register_match(&connlabels_mt_reg);
  96}
  97
  98static void __exit connlabel_mt_exit(void)
  99{
 100        xt_unregister_match(&connlabels_mt_reg);
 101}
 102
 103module_init(connlabel_mt_init);
 104module_exit(connlabel_mt_exit);
 105