114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/*
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* Copyright (C)2006 USAGI/WIDE Project
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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*/
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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("ip6t_tables match for MH");
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MODULE_LICENSE("GPL");
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#ifdef DEBUG_IP_FIREWALL_USER
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#define duprintf(format, args...) printk(format , ## args)
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#else
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#define duprintf(format, args...)
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#endif
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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
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const struct xt_match *match,
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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bool *hotdrop)
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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 = matchinfo;
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/* Must not be a fragment. */
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if (offset)
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return false;
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mh = skb_header_pointer(skb, protoff, 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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duprintf("Dropping evil MH tinygram.\n");
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*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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duprintf("Dropping invalid MH Payload Proto: %u\n",
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mh->ip6mh_proto);
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*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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/* Called when user tries to insert an entry of this type. */
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static bool
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mh_checkentry(const char *tablename,
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const void *entry,
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const struct xt_match *match,
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void *matchinfo,
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unsigned int hook_mask)
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{
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const struct ip6t_mh *mhinfo = matchinfo;
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/* Must specify no unknown invflags */
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return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
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}
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static struct xt_match mh_match __read_mostly = {
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.name = "mh",
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.family = AF_INET6,
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.checkentry = mh_checkentry,
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.match = match,
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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 ip6t_mh_init(void)
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{
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return xt_register_match(&mh_match);
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}
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static void __exit ip6t_mh_fini(void)
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{
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xt_unregister_match(&mh_match);
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}
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module_init(ip6t_mh_init);
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module_exit(ip6t_mh_fini);
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