diff options
Diffstat (limited to 'kernel/net/netfilter/xt_length.c')
-rw-r--r-- | kernel/net/netfilter/xt_length.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/kernel/net/netfilter/xt_length.c b/kernel/net/netfilter/xt_length.c new file mode 100644 index 000000000..176e5570a --- /dev/null +++ b/kernel/net/netfilter/xt_length.c @@ -0,0 +1,70 @@ +/* Kernel module to match packet length. */ +/* (C) 1999-2001 James Morris <jmorros@intercode.com.au> + * + * 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. + */ + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/ipv6.h> +#include <net/ip.h> + +#include <linux/netfilter/xt_length.h> +#include <linux/netfilter/x_tables.h> + +MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); +MODULE_DESCRIPTION("Xtables: Packet length (Layer3,4,5) match"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_length"); +MODULE_ALIAS("ip6t_length"); + +static bool +length_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_length_info *info = par->matchinfo; + u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len); + + return (pktlen >= info->min && pktlen <= info->max) ^ info->invert; +} + +static bool +length_mt6(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_length_info *info = par->matchinfo; + const u_int16_t pktlen = ntohs(ipv6_hdr(skb)->payload_len) + + sizeof(struct ipv6hdr); + + return (pktlen >= info->min && pktlen <= info->max) ^ info->invert; +} + +static struct xt_match length_mt_reg[] __read_mostly = { + { + .name = "length", + .family = NFPROTO_IPV4, + .match = length_mt, + .matchsize = sizeof(struct xt_length_info), + .me = THIS_MODULE, + }, + { + .name = "length", + .family = NFPROTO_IPV6, + .match = length_mt6, + .matchsize = sizeof(struct xt_length_info), + .me = THIS_MODULE, + }, +}; + +static int __init length_mt_init(void) +{ + return xt_register_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg)); +} + +static void __exit length_mt_exit(void) +{ + xt_unregister_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg)); +} + +module_init(length_mt_init); +module_exit(length_mt_exit); |