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>
88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
/*
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* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
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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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* Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
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*/
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/skbuff.h>
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#include <linux/net.h>
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#include <linux/netfilter/xt_statistic.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
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MODULE_ALIAS("ipt_statistic");
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MODULE_ALIAS("ip6t_statistic");
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static DEFINE_SPINLOCK(nth_lock);
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static bool
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statistic_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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struct xt_statistic_info *info = (void *)par->matchinfo;
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bool ret = info->flags & XT_STATISTIC_INVERT;
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switch (info->mode) {
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case XT_STATISTIC_MODE_RANDOM:
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if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
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ret = !ret;
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break;
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case XT_STATISTIC_MODE_NTH:
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info = info->master;
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spin_lock_bh(&nth_lock);
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if (info->u.nth.count++ == info->u.nth.every) {
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info->u.nth.count = 0;
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ret = !ret;
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}
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spin_unlock_bh(&nth_lock);
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break;
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}
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return ret;
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}
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static bool
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statistic_mt_check(const char *tablename, const void *entry,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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struct xt_statistic_info *info = matchinfo;
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if (info->mode > XT_STATISTIC_MODE_MAX ||
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info->flags & ~XT_STATISTIC_MASK)
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return false;
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info->master = info;
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return true;
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}
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static struct xt_match xt_statistic_mt_reg __read_mostly = {
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.name = "statistic",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.match = statistic_mt,
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.checkentry = statistic_mt_check,
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.matchsize = sizeof(struct xt_statistic_info),
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.me = THIS_MODULE,
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};
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static int __init statistic_mt_init(void)
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{
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return xt_register_match(&xt_statistic_mt_reg);
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}
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static void __exit statistic_mt_exit(void)
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{
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xt_unregister_match(&xt_statistic_mt_reg);
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}
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module_init(statistic_mt_init);
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module_exit(statistic_mt_exit);
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