f7108a20de
The function signatures for Xtables extensions have grown over time. It involves a lot of typing/replication, and also a bit of stack space even if they are not used. Realize an NFWS2008 idea and pack them into structs. The skb remains outside of the struct so gcc can continue to apply its optimizations. This patch does this for match extensions' match functions. A few ambiguities have also been addressed. The "offset" parameter for example has been renamed to "fragoff" (there are so many different offsets already) and "protoff" to "thoff" (there is more than just one protocol here, so clarify). Signed-off-by: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
/* Kernel module to match packet length. */
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/* (C) 1999-2001 James Morris <jmorros@intercode.com.au>
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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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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/ipv6.h>
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#include <net/ip.h>
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#include <linux/netfilter/xt_length.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
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MODULE_DESCRIPTION("Xtables: Packet length (Layer3,4,5) match");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_length");
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MODULE_ALIAS("ip6t_length");
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static bool
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length_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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const struct xt_length_info *info = par->matchinfo;
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u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len);
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return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
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}
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static bool
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length_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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const struct xt_length_info *info = par->matchinfo;
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const u_int16_t pktlen = ntohs(ipv6_hdr(skb)->payload_len) +
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sizeof(struct ipv6hdr);
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return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
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}
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static struct xt_match length_mt_reg[] __read_mostly = {
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{
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.name = "length",
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.family = NFPROTO_IPV4,
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.match = length_mt,
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.matchsize = sizeof(struct xt_length_info),
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.me = THIS_MODULE,
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},
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{
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.name = "length",
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.family = NFPROTO_IPV6,
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.match = length_mt6,
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.matchsize = sizeof(struct xt_length_info),
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.me = THIS_MODULE,
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},
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};
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static int __init length_mt_init(void)
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{
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return xt_register_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
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}
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static void __exit length_mt_exit(void)
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{
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xt_unregister_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
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}
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module_init(length_mt_init);
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module_exit(length_mt_exit);
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