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