9fb9cbb108
The existing connection tracking subsystem in netfilter can only handle ipv4. There were basically two choices present to add connection tracking support for ipv6. We could either duplicate all of the ipv4 connection tracking code into an ipv6 counterpart, or (the choice taken by these patches) we could design a generic layer that could handle both ipv4 and ipv6 and thus requiring only one sub-protocol (TCP, UDP, etc.) connection tracking helper module to be written. In fact nf_conntrack is capable of working with any layer 3 protocol. The existing ipv4 specific conntrack code could also not deal with the pecularities of doing connection tracking on ipv6, which is also cured here. For example, these issues include: 1) ICMPv6 handling, which is used for neighbour discovery in ipv6 thus some messages such as these should not participate in connection tracking since effectively they are like ARP messages 2) fragmentation must be handled differently in ipv6, because the simplistic "defrag, connection track and NAT, refrag" (which the existing ipv4 connection tracking does) approach simply isn't feasible in ipv6 3) ipv6 extension header parsing must occur at the correct spots before and after connection tracking decisions, and there were no provisions for this in the existing connection tracking design 4) ipv6 has no need for stateful NAT The ipv4 specific conntrack layer is kept around, until all of the ipv4 specific conntrack helpers are ported over to nf_conntrack and it is feature complete. Once that occurs, the old conntrack stuff will get placed into the feature-removal-schedule and we will fully kill it off 6 months later. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
123 lines
3.4 KiB
C
123 lines
3.4 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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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_CONNMARK.h>
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#include <net/netfilter/nf_conntrack_compat.h>
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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 void *targinfo,
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void *userinfo)
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{
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const struct ipt_connmark_target_info *markinfo = targinfo;
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u_int32_t diff;
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u_int32_t nfmark;
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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 IPT_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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break;
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case IPT_CONNMARK_SAVE:
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newmark = (*ctmark & ~markinfo->mask) | ((*pskb)->nfmark & markinfo->mask);
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if (*ctmark != newmark)
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*ctmark = newmark;
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break;
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case IPT_CONNMARK_RESTORE:
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nfmark = (*pskb)->nfmark;
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diff = (*ctmark ^ nfmark) & markinfo->mask;
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if (diff != 0)
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(*pskb)->nfmark = nfmark ^ diff;
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break;
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}
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}
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return IPT_CONTINUE;
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}
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static int
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checkentry(const char *tablename,
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const struct ipt_entry *e,
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void *targinfo,
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unsigned int targinfosize,
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unsigned int hook_mask)
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{
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struct ipt_connmark_target_info *matchinfo = targinfo;
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if (targinfosize != IPT_ALIGN(sizeof(struct ipt_connmark_target_info))) {
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printk(KERN_WARNING "CONNMARK: targinfosize %u != %Zu\n",
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targinfosize,
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IPT_ALIGN(sizeof(struct ipt_connmark_target_info)));
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return 0;
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}
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if (matchinfo->mode == IPT_CONNMARK_RESTORE) {
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if (strcmp(tablename, "mangle") != 0) {
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printk(KERN_WARNING "CONNMARK: restore can only be called from \"mangle\" table, not \"%s\"\n", 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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static struct ipt_target ipt_connmark_reg = {
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.name = "CONNMARK",
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.target = &target,
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.checkentry = &checkentry,
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.me = THIS_MODULE
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};
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static int __init init(void)
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{
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need_ip_conntrack();
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return ipt_register_target(&ipt_connmark_reg);
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}
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static void __exit fini(void)
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{
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ipt_unregister_target(&ipt_connmark_reg);
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}
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module_init(init);
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module_exit(fini);
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