LXR linux/net/netfilter/xt

   1/* Xtables module to match packets using a BPF filter.
   2 * Copyright 2013 Google Inc.
   3 * Written by Willem de Bruijn <willemb@google.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/skbuff.h>
  12#include <linux/filter.h>
  13
  14#include <linux/netfilter/xt_bpf.h>
  15#include <linux/netfilter/x_tables.h>
  16
  17MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
  18MODULE_DESCRIPTION("Xtables: BPF filter match");
  19MODULE_LICENSE("GPL");
  20MODULE_ALIAS("ipt_bpf");
  21MODULE_ALIAS("ip6t_bpf");
  22
  23static int bpf_mt_check(const struct xt_mtchk_param *par)
  24{
  25        struct xt_bpf_info *info = par->matchinfo;
  26        struct sock_fprog program;
  27
  28        program.len = info->bpf_program_num_elem;
  29        program.filter = (struct sock_filter __user *) info->bpf_program;
  30        if (sk_unattached_filter_create(&info->filter, &program)) {
  31                pr_info("bpf: check failed: parse error\n");
  32                return -EINVAL;
  33        }
  34
  35        return 0;
  36}
  37
  38static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
  39{
  40        const struct xt_bpf_info *info = par->matchinfo;
  41
  42        return SK_RUN_FILTER(info->filter, skb);
  43}
  44
  45static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
  46{
  47        const struct xt_bpf_info *info = par->matchinfo;
  48        sk_unattached_filter_destroy(info->filter);
  49}
  50
  51static struct xt_match bpf_mt_reg __read_mostly = {
  52        .name           = "bpf",
  53        .revision       = 0,
  54        .family         = NFPROTO_UNSPEC,
  55        .checkentry     = bpf_mt_check,
  56        .match          = bpf_mt,
  57        .destroy        = bpf_mt_destroy,
  58        .matchsize      = sizeof(struct xt_bpf_info),
  59        .me             = THIS_MODULE,
  60};
  61
  62static int __init bpf_mt_init(void)
  63{
  64        return xt_register_match(&bpf_mt_reg);
  65}
  66
  67static void __exit bpf_mt_exit(void)
  68{
  69        xt_unregister_match(&bpf_mt_reg);
  70}
  71
  72module_init(bpf_mt_init);
  73module_exit(bpf_mt_exit);
  74