262 lines
7.2 KiB
C
262 lines
7.2 KiB
C
/*
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* xt_CONNMARK - Netfilter module to modify the connection mark values
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*
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* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
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* by Henrik Nordstrom <hno@marasystems.com>
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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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* Jan Engelhardt <jengelh@computergmbh.de>
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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/ip.h>
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#include <net/checksum.h>
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MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
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MODULE_DESCRIPTION("Xtables: connection mark modification");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_CONNMARK");
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MODULE_ALIAS("ip6t_CONNMARK");
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_CONNMARK.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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static unsigned int
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connmark_tg_v0(struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, unsigned int hooknum,
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const struct xt_target *target, const void *targinfo)
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{
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const struct xt_connmark_target_info *markinfo = targinfo;
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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u_int32_t diff;
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u_int32_t mark;
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u_int32_t newmark;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct) {
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switch(markinfo->mode) {
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case XT_CONNMARK_SET:
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newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
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if (newmark != ct->mark) {
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ct->mark = newmark;
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nf_conntrack_event_cache(IPCT_MARK, skb);
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}
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break;
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case XT_CONNMARK_SAVE:
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newmark = (ct->mark & ~markinfo->mask) |
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(skb->mark & markinfo->mask);
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if (ct->mark != newmark) {
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ct->mark = newmark;
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nf_conntrack_event_cache(IPCT_MARK, skb);
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}
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break;
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case XT_CONNMARK_RESTORE:
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mark = skb->mark;
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diff = (ct->mark ^ mark) & markinfo->mask;
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skb->mark = mark ^ diff;
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break;
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}
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}
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return XT_CONTINUE;
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}
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static unsigned int
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connmark_tg(struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, unsigned int hooknum,
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const struct xt_target *target, const void *targinfo)
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{
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const struct xt_connmark_tginfo1 *info = targinfo;
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enum ip_conntrack_info ctinfo;
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struct nf_conn *ct;
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u_int32_t newmark;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct == NULL)
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return XT_CONTINUE;
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switch (info->mode) {
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case XT_CONNMARK_SET:
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newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
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if (ct->mark != newmark) {
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ct->mark = newmark;
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nf_conntrack_event_cache(IPCT_MARK, skb);
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}
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break;
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case XT_CONNMARK_SAVE:
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newmark = (ct->mark & ~info->ctmask) ^
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(skb->mark & info->nfmask);
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if (ct->mark != newmark) {
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ct->mark = newmark;
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nf_conntrack_event_cache(IPCT_MARK, skb);
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}
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break;
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case XT_CONNMARK_RESTORE:
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newmark = (skb->mark & ~info->nfmask) ^
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(ct->mark & info->ctmask);
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skb->mark = newmark;
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break;
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}
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return XT_CONTINUE;
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}
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static bool
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connmark_tg_check_v0(const char *tablename, const void *entry,
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const struct xt_target *target, void *targinfo,
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unsigned int hook_mask)
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{
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const struct xt_connmark_target_info *matchinfo = targinfo;
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if (matchinfo->mode == XT_CONNMARK_RESTORE) {
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if (strcmp(tablename, "mangle") != 0) {
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printk(KERN_WARNING "CONNMARK: restore can only be "
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"called from \"mangle\" table, not \"%s\"\n",
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tablename);
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return false;
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}
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}
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if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
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printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
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return false;
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}
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if (nf_ct_l3proto_try_module_get(target->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", target->family);
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return false;
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}
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return true;
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}
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static bool
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connmark_tg_check(const char *tablename, const void *entry,
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const struct xt_target *target, void *targinfo,
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unsigned int hook_mask)
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{
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if (nf_ct_l3proto_try_module_get(target->family) < 0) {
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printk(KERN_WARNING "cannot load conntrack support for "
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"proto=%u\n", target->family);
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return false;
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}
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return true;
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}
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static void
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connmark_tg_destroy(const struct xt_target *target, void *targinfo)
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{
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nf_ct_l3proto_module_put(target->family);
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}
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#ifdef CONFIG_COMPAT
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struct compat_xt_connmark_target_info {
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compat_ulong_t mark, mask;
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u_int8_t mode;
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u_int8_t __pad1;
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u_int16_t __pad2;
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};
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static void connmark_tg_compat_from_user_v0(void *dst, void *src)
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{
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const struct compat_xt_connmark_target_info *cm = src;
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struct xt_connmark_target_info m = {
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.mark = cm->mark,
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.mask = cm->mask,
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.mode = cm->mode,
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};
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memcpy(dst, &m, sizeof(m));
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}
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static int connmark_tg_compat_to_user_v0(void __user *dst, void *src)
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{
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const struct xt_connmark_target_info *m = src;
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struct compat_xt_connmark_target_info cm = {
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.mark = m->mark,
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.mask = m->mask,
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.mode = m->mode,
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};
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return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
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}
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#endif /* CONFIG_COMPAT */
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static struct xt_target connmark_tg_reg[] __read_mostly = {
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{
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.name = "CONNMARK",
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.revision = 0,
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.family = AF_INET,
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.checkentry = connmark_tg_check_v0,
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.destroy = connmark_tg_destroy,
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.target = connmark_tg_v0,
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.targetsize = sizeof(struct xt_connmark_target_info),
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#ifdef CONFIG_COMPAT
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.compatsize = sizeof(struct compat_xt_connmark_target_info),
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.compat_from_user = connmark_tg_compat_from_user_v0,
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.compat_to_user = connmark_tg_compat_to_user_v0,
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#endif
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.me = THIS_MODULE
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},
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{
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.name = "CONNMARK",
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.revision = 0,
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.family = AF_INET6,
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.checkentry = connmark_tg_check_v0,
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.destroy = connmark_tg_destroy,
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.target = connmark_tg_v0,
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.targetsize = sizeof(struct xt_connmark_target_info),
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#ifdef CONFIG_COMPAT
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.compatsize = sizeof(struct compat_xt_connmark_target_info),
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.compat_from_user = connmark_tg_compat_from_user_v0,
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.compat_to_user = connmark_tg_compat_to_user_v0,
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#endif
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.me = THIS_MODULE
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},
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{
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.name = "CONNMARK",
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.revision = 1,
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.family = AF_INET,
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.checkentry = connmark_tg_check,
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.target = connmark_tg,
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.targetsize = sizeof(struct xt_connmark_tginfo1),
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.destroy = connmark_tg_destroy,
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.me = THIS_MODULE,
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},
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{
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.name = "CONNMARK",
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.revision = 1,
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.family = AF_INET6,
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.checkentry = connmark_tg_check,
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.target = connmark_tg,
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.targetsize = sizeof(struct xt_connmark_tginfo1),
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.destroy = connmark_tg_destroy,
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.me = THIS_MODULE,
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},
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};
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static int __init connmark_tg_init(void)
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{
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return xt_register_targets(connmark_tg_reg,
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ARRAY_SIZE(connmark_tg_reg));
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}
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static void __exit connmark_tg_exit(void)
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{
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xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg));
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}
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module_init(connmark_tg_init);
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module_exit(connmark_tg_exit);
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