// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C)2006 USAGI/WIDE Project
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*
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* Author:
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* Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
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*
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* Based on net/netfilter/xt_tcpudp.c
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/module.h>
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#include <net/ip.h>
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#include <linux/ipv6.h>
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#include <net/ipv6.h>
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#include <net/mip6.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv6/ip6t_mh.h>
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MODULE_DESCRIPTION("Xtables: IPv6 Mobility Header match");
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MODULE_LICENSE("GPL");
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/* Returns 1 if the type is matched by the range, 0 otherwise */
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static inline bool
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type_match(u_int8_t min, u_int8_t max, u_int8_t type, bool invert)
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{
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return (type >= min && type <= max) ^ invert;
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}
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static bool mh_mt6(const struct sk_buff *skb, struct xt_action_param *par)
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{
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struct ip6_mh _mh;
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const struct ip6_mh *mh;
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const struct ip6t_mh *mhinfo = par->matchinfo;
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/* Must not be a fragment. */
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if (par->fragoff != 0)
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return false;
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mh = skb_header_pointer(skb, par->thoff, sizeof(_mh), &_mh);
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if (mh == NULL) {
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/* We've been asked to examine this packet, and we
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can't. Hence, no choice but to drop. */
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pr_debug("Dropping evil MH tinygram.\n");
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par->hotdrop = true;
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return false;
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}
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if (mh->ip6mh_proto != IPPROTO_NONE) {
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pr_debug("Dropping invalid MH Payload Proto: %u\n",
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mh->ip6mh_proto);
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par->hotdrop = true;
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return false;
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}
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return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
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!!(mhinfo->invflags & IP6T_MH_INV_TYPE));
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}
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static int mh_mt6_check(const struct xt_mtchk_param *par)
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{
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const struct ip6t_mh *mhinfo = par->matchinfo;
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/* Must specify no unknown invflags */
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return (mhinfo->invflags & ~IP6T_MH_INV_MASK) ? -EINVAL : 0;
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}
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static struct xt_match mh_mt6_reg __read_mostly = {
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.name = "mh",
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.family = NFPROTO_IPV6,
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.checkentry = mh_mt6_check,
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.match = mh_mt6,
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.matchsize = sizeof(struct ip6t_mh),
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.proto = IPPROTO_MH,
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.me = THIS_MODULE,
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};
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static int __init mh_mt6_init(void)
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{
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return xt_register_match(&mh_mt6_reg);
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}
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static void __exit mh_mt6_exit(void)
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{
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xt_unregister_match(&mh_mt6_reg);
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}
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module_init(mh_mt6_init);
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module_exit(mh_mt6_exit);
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