LXR linux/net/netfilter/xt

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * (C) 2013 Astaro GmbH & Co KG
   4 */
   5
   6#include <linux/module.h>
   7#include <linux/skbuff.h>
   8#include <net/netfilter/nf_conntrack.h>
   9#include <net/netfilter/nf_conntrack_ecache.h>
  10#include <net/netfilter/nf_conntrack_labels.h>
  11#include <linux/netfilter/x_tables.h>
  12
  13MODULE_LICENSE("GPL");
  14MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
  15MODULE_DESCRIPTION("Xtables: add/match connection tracking labels");
  16MODULE_ALIAS("ipt_connlabel");
  17MODULE_ALIAS("ip6t_connlabel");
  18
  19static bool
  20connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par)
  21{
  22        const struct xt_connlabel_mtinfo *info = par->matchinfo;
  23        enum ip_conntrack_info ctinfo;
  24        struct nf_conn_labels *labels;
  25        struct nf_conn *ct;
  26        bool invert = info->options & XT_CONNLABEL_OP_INVERT;
  27
  28        ct = nf_ct_get(skb, &ctinfo);
  29        if (ct == NULL)
  30                return invert;
  31
  32        labels = nf_ct_labels_find(ct);
  33        if (!labels)
  34                return invert;
  35
  36        if (test_bit(info->bit, labels->bits))
  37                return !invert;
  38
  39        if (info->options & XT_CONNLABEL_OP_SET) {
  40                if (!test_and_set_bit(info->bit, labels->bits))
  41                        nf_conntrack_event_cache(IPCT_LABEL, ct);
  42
  43                return !invert;
  44        }
  45
  46        return invert;
  47}
  48
  49static int connlabel_mt_check(const struct xt_mtchk_param *par)
  50{
  51        const int options = XT_CONNLABEL_OP_INVERT |
  52                            XT_CONNLABEL_OP_SET;
  53        struct xt_connlabel_mtinfo *info = par->matchinfo;
  54        int ret;
  55
  56        if (info->options & ~options) {
  57                pr_info_ratelimited("Unknown options in mask %x\n",
  58                                    info->options);
  59                return -EINVAL;
  60        }
  61
  62        ret = nf_ct_netns_get(par->net, par->family);
  63        if (ret < 0) {
  64                pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
  65                                    par->family);
  66                return ret;
  67        }
  68
  69        ret = nf_connlabels_get(par->net, info->bit);
  70        if (ret < 0)
  71                nf_ct_netns_put(par->net, par->family);
  72        return ret;
  73}
  74
  75static void connlabel_mt_destroy(const struct xt_mtdtor_param *par)
  76{
  77        nf_connlabels_put(par->net);
  78        nf_ct_netns_put(par->net, par->family);
  79}
  80
  81static struct xt_match connlabels_mt_reg __read_mostly = {
  82        .name           = "connlabel",
  83        .family         = NFPROTO_UNSPEC,
  84        .checkentry     = connlabel_mt_check,
  85        .match          = connlabel_mt,
  86        .matchsize      = sizeof(struct xt_connlabel_mtinfo),
  87        .destroy        = connlabel_mt_destroy,
  88        .me             = THIS_MODULE,
  89};
  90
  91static int __init connlabel_mt_init(void)
  92{
  93        return xt_register_match(&connlabels_mt_reg);
  94}
  95
  96static void __exit connlabel_mt_exit(void)
  97{
  98        xt_unregister_match(&connlabels_mt_reg);
  99}
 100
 101module_init(connlabel_mt_init);
 102module_exit(connlabel_mt_exit);
 103