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/* iptables module for the packet checksum mangling
*
* (C) 2002 by Harald Welte <laforge@netfilter.org>
* (C) 2010 Red Hat, Inc.
*
* Author: Michael S. Tsirkin <mst@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_CHECKSUM.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael S. Tsirkin <mst@redhat.com>");
MODULE_DESCRIPTION("Xtables: checksum modification");
MODULE_ALIAS("ipt_CHECKSUM");
MODULE_ALIAS("ip6t_CHECKSUM");
static unsigned int
checksum_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
if (skb->ip_summed == CHECKSUM_PARTIAL)
skb_checksum_help(skb);
return XT_CONTINUE;
}
static int checksum_tg_check(const struct xt_tgchk_param *par)
{
const struct xt_CHECKSUM_info *einfo = par->targinfo;
if (einfo->operation & ~XT_CHECKSUM_OP_FILL) {
pr_info("unsupported CHECKSUM operation %x\n", einfo->operation);
return -EINVAL;
}
if (!einfo->operation) {
pr_info("no CHECKSUM operation enabled\n");
return -EINVAL;
}
return 0;
}
static struct xt_target checksum_tg_reg __read_mostly = {
.name = "CHECKSUM",
.family = NFPROTO_UNSPEC,
.target = checksum_tg,
.targetsize = sizeof(struct xt_CHECKSUM_info),
.table = "mangle",
.checkentry = checksum_tg_check,
.me = THIS_MODULE,
};
static int __init checksum_tg_init(void)
{
return xt_register_target(&checksum_tg_reg);
}
static void __exit checksum_tg_exit(void)
{
xt_unregister_target(&checksum_tg_reg);
}
module_init(checksum_tg_init);
module_exit(checksum_tg_exit);
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