linux/net/ipv6/netfilter/ip6t_hbh.c

// SPDX-License-Identifier: GPL-2.0-only
/* Kernel module to match Hop-by-Hop and Destination parameters. */

/* (C) 2001-2002 Andras Kis-Szabo <[email protected]>
 */
#define pr_fmt(fmt) …
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <linux/types.h>
#include <net/checksum.h>
#include <net/ipv6.h>

#include <asm/byteorder.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_ipv6/ip6t_opts.h>

MODULE_LICENSE(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;
MODULE_ALIAS(…) …;

/*
 *  (Type & 0xC0) >> 6
 *	0	-> ignorable
 *	1	-> must drop the packet
 *	2	-> send ICMP PARM PROB regardless and drop packet
 *	3	-> Send ICMP if not a multicast address and drop packet
 *  (Type & 0x20) >> 5
 *	0	-> invariant
 *	1	-> can change the routing
 *  (Type & 0x1F) Type
 *	0	-> Pad1 (only 1 byte!)
 *	1	-> PadN LENGTH info (total length = length + 2)
 *	C0 | 2	-> JUMBO 4 x x x x ( xxxx > 64k )
 *	5	-> RTALERT 2 x x
 */

static struct xt_match hbh_mt6_reg[] __read_mostly;

static bool
hbh_mt6(const struct sk_buff *skb, struct xt_action_param *par)
{ … }

static int hbh_mt6_check(const struct xt_mtchk_param *par)
{ … }

static struct xt_match hbh_mt6_reg[] __read_mostly = …;

static int __init hbh_mt6_init(void)
{ … }

static void __exit hbh_mt6_exit(void)
{ … }

module_init(…) …;
module_exit(hbh_mt6_exit);