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>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/* iptables module to match on related connections */
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/*
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* (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
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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/netfilter.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_helper.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>");
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MODULE_DESCRIPTION("Xtables: Related connection matching");
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MODULE_ALIAS("ipt_helper");
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MODULE_ALIAS("ip6t_helper");
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static bool
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helper_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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const struct xt_helper_info *info = par->matchinfo;
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const struct nf_conn *ct;
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const struct nf_conn_help *master_help;
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const struct nf_conntrack_helper *helper;
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enum ip_conntrack_info ctinfo;
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bool ret = info->invert;
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct || !ct->master)
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return ret;
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master_help = nfct_help(ct->master);
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if (!master_help)
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return ret;
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/* rcu_read_lock()ed by nf_hook_slow */
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helper = rcu_dereference(master_help->helper);
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if (!helper)
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return ret;
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if (info->name[0] == '\0')
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ret = !ret;
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else
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ret ^= !strncmp(helper->name, info->name,
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strlen(helper->name));
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return ret;
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}
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static bool
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helper_mt_check(const char *tablename, const void *inf,
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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_helper_info *info = matchinfo;
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if (nf_ct_l3proto_try_module_get(match->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", match->family);
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return false;
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}
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info->name[29] = '\0';
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return true;
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}
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static void helper_mt_destroy(const struct xt_match *match, void *matchinfo)
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{
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nf_ct_l3proto_module_put(match->family);
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}
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static struct xt_match helper_mt_reg[] __read_mostly = {
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{
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.name = "helper",
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.family = NFPROTO_IPV4,
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.checkentry = helper_mt_check,
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.match = helper_mt,
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.destroy = helper_mt_destroy,
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.matchsize = sizeof(struct xt_helper_info),
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.me = THIS_MODULE,
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},
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{
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.name = "helper",
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.family = NFPROTO_IPV6,
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.checkentry = helper_mt_check,
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.match = helper_mt,
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.destroy = helper_mt_destroy,
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.matchsize = sizeof(struct xt_helper_info),
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.me = THIS_MODULE,
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},
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};
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static int __init helper_mt_init(void)
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{
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return xt_register_matches(helper_mt_reg, ARRAY_SIZE(helper_mt_reg));
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}
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static void __exit helper_mt_exit(void)
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{
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xt_unregister_matches(helper_mt_reg, ARRAY_SIZE(helper_mt_reg));
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}
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module_init(helper_mt_init);
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module_exit(helper_mt_exit);
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