diff options
Diffstat (limited to 'kernel/net/ipv6/netfilter/ip6t_mh.c')
-rw-r--r-- | kernel/net/ipv6/netfilter/ip6t_mh.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/kernel/net/ipv6/netfilter/ip6t_mh.c b/kernel/net/ipv6/netfilter/ip6t_mh.c new file mode 100644 index 000000000..0c90c66b1 --- /dev/null +++ b/kernel/net/ipv6/netfilter/ip6t_mh.c @@ -0,0 +1,94 @@ +/* + * 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, struct xt_action_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); |