184 lines
4.9 KiB
C
184 lines
4.9 KiB
C
/* This kernel module is used to modify the connection mark values, or
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* to optionally restore the skb nfmark from the connection mark
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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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*
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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@marasytems.com>");
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MODULE_DESCRIPTION("IP tables CONNMARK matching module");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_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_compat.h>
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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#include <net/netfilter/nf_conntrack_ecache.h>
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#endif
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static unsigned int
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target(struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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unsigned int hooknum,
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const struct xt_target *target,
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const void *targinfo)
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{
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const struct xt_connmark_target_info *markinfo = targinfo;
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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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u_int32_t ctinfo;
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u_int32_t *ctmark = nf_ct_get_mark(*pskb, &ctinfo);
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if (ctmark) {
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switch(markinfo->mode) {
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case XT_CONNMARK_SET:
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newmark = (*ctmark & ~markinfo->mask) | markinfo->mark;
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if (newmark != *ctmark) {
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*ctmark = newmark;
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#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
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ip_conntrack_event_cache(IPCT_MARK, *pskb);
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#else
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nf_conntrack_event_cache(IPCT_MARK, *pskb);
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#endif
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}
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break;
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case XT_CONNMARK_SAVE:
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newmark = (*ctmark & ~markinfo->mask) |
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((*pskb)->mark & markinfo->mask);
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if (*ctmark != newmark) {
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*ctmark = newmark;
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#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
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ip_conntrack_event_cache(IPCT_MARK, *pskb);
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#else
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nf_conntrack_event_cache(IPCT_MARK, *pskb);
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#endif
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}
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break;
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case XT_CONNMARK_RESTORE:
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mark = (*pskb)->mark;
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diff = (*ctmark ^ mark) & markinfo->mask;
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if (diff != 0)
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(*pskb)->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 int
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checkentry(const char *tablename,
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const void *entry,
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const struct xt_target *target,
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void *targinfo,
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unsigned int hook_mask)
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{
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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 0;
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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 0;
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}
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return 1;
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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 compat_from_user(void *dst, void *src)
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{
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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 compat_to_user(void __user *dst, void *src)
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{
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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 xt_connmark_target[] = {
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{
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.name = "CONNMARK",
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.family = AF_INET,
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.checkentry = checkentry,
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.target = target,
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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 = compat_from_user,
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.compat_to_user = compat_to_user,
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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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.family = AF_INET6,
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.checkentry = checkentry,
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.target = target,
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.targetsize = sizeof(struct xt_connmark_target_info),
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.me = THIS_MODULE
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},
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};
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static int __init xt_connmark_init(void)
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{
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need_conntrack();
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return xt_register_targets(xt_connmark_target,
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ARRAY_SIZE(xt_connmark_target));
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}
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static void __exit xt_connmark_fini(void)
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{
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xt_unregister_targets(xt_connmark_target,
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ARRAY_SIZE(xt_connmark_target));
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}
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module_init(xt_connmark_init);
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module_exit(xt_connmark_fini);
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