Skip to content

Commit

Permalink
[NETFILTER]: xt_CONNMARK target, revision 1
Browse files Browse the repository at this point in the history 
Introduces the xt_CONNMARK target revision 1. It uses fixed types, and
also uses the more expressive XOR logic. Futhermore, it allows to
selectively pick bits from both the ctmark and the nfmark in the SAVE
and RESTORE operations.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Jan Engelhardt authored and David S. Miller committed Jan 28, 2008
1 parent 8b6f3f6 commit 0dc8c76
Show file tree
Hide file tree
Showing 2 changed files with 102 additions and 20 deletions.
5 changes: 5 additions & 0 deletions include/linux/netfilter/xt_CONNMARK.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,4 +22,9 @@ struct xt_connmark_target_info {
u_int8_t mode;
};

struct xt_connmark_tginfo1 {
u_int32_t ctmark, ctmask, nfmask;
u_int8_t mode;
};

#endif /*_XT_CONNMARK_H_target*/
117 changes: 97 additions & 20 deletions net/netfilter/xt_CONNMARK.c
View file
Original file line number Diff line number Diff line change
@@ -1,8 +1,10 @@
/* This kernel module is used to modify the connection mark values, or
* to optionally restore the skb nfmark from the connection mark
/*
* xt_CONNMARK - Netfilter module to modify the connection mark values
*
* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
* by Henrik Nordstrom <hno@marasystems.com>
* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
* by Henrik Nordstrom <hno@marasystems.com>
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
* Jan Engelhardt <jengelh@computergmbh.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
Expand Down Expand Up @@ -34,9 +36,9 @@ MODULE_ALIAS("ip6t_CONNMARK");
#include <net/netfilter/nf_conntrack_ecache.h>

static unsigned int
connmark_tg(struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, unsigned int hooknum,
const struct xt_target *target, const void *targinfo)
connmark_tg_v0(struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, unsigned int hooknum,
const struct xt_target *target, const void *targinfo)
{
const struct xt_connmark_target_info *markinfo = targinfo;
struct nf_conn *ct;
Expand Down Expand Up @@ -74,10 +76,50 @@ connmark_tg(struct sk_buff *skb, const struct net_device *in,
return XT_CONTINUE;
}

static unsigned int
connmark_tg(struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, unsigned int hooknum,
const struct xt_target *target, const void *targinfo)
{
const struct xt_connmark_tginfo1 *info = targinfo;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u_int32_t newmark;

ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
return XT_CONTINUE;

switch (info->mode) {
case XT_CONNMARK_SET:
newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, skb);
}
break;
case XT_CONNMARK_SAVE:
newmark = (ct->mark & ~info->ctmask) ^
(skb->mark & info->nfmask);
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, skb);
}
break;
case XT_CONNMARK_RESTORE:
newmark = (skb->mark & ~info->nfmask) ^
(ct->mark & info->ctmask);
skb->mark = newmark;
break;
}

return XT_CONTINUE;
}

static bool
connmark_tg_check(const char *tablename, const void *entry,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
connmark_tg_check_v0(const char *tablename, const void *entry,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
{
const struct xt_connmark_target_info *matchinfo = targinfo;

Expand All @@ -101,6 +143,19 @@ connmark_tg_check(const char *tablename, const void *entry,
return true;
}

static bool
connmark_tg_check(const char *tablename, const void *entry,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
{
if (nf_ct_l3proto_try_module_get(target->family) < 0) {
printk(KERN_WARNING "cannot load conntrack support for "
"proto=%u\n", target->family);
return false;
}
return true;
}

static void
connmark_tg_destroy(const struct xt_target *target, void *targinfo)
{
Expand All @@ -115,7 +170,7 @@ struct compat_xt_connmark_target_info {
u_int16_t __pad2;
};

static void connmark_tg_compat_from_user(void *dst, void *src)
static void connmark_tg_compat_from_user_v0(void *dst, void *src)
{
const struct compat_xt_connmark_target_info *cm = src;
struct xt_connmark_target_info m = {
Expand All @@ -126,7 +181,7 @@ static void connmark_tg_compat_from_user(void *dst, void *src)
memcpy(dst, &m, sizeof(m));
}

static int connmark_tg_compat_to_user(void __user *dst, void *src)
static int connmark_tg_compat_to_user_v0(void __user *dst, void *src)
{
const struct xt_connmark_target_info *m = src;
struct compat_xt_connmark_target_info cm = {
Expand All @@ -141,32 +196,54 @@ static int connmark_tg_compat_to_user(void __user *dst, void *src)
static struct xt_target connmark_tg_reg[] __read_mostly = {
{
.name = "CONNMARK",
.revision = 0,
.family = AF_INET,
.checkentry = connmark_tg_check,
.checkentry = connmark_tg_check_v0,
.destroy = connmark_tg_destroy,
.target = connmark_tg,
.target = connmark_tg_v0,
.targetsize = sizeof(struct xt_connmark_target_info),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_connmark_target_info),
.compat_from_user = connmark_tg_compat_from_user,
.compat_to_user = connmark_tg_compat_to_user,
.compat_from_user = connmark_tg_compat_from_user_v0,
.compat_to_user = connmark_tg_compat_to_user_v0,
#endif
.me = THIS_MODULE
},
{
.name = "CONNMARK",
.revision = 0,
.family = AF_INET6,
.checkentry = connmark_tg_check,
.checkentry = connmark_tg_check_v0,
.destroy = connmark_tg_destroy,
.target = connmark_tg,
.target = connmark_tg_v0,
.targetsize = sizeof(struct xt_connmark_target_info),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_connmark_target_info),
.compat_from_user = connmark_tg_compat_from_user,
.compat_to_user = connmark_tg_compat_to_user,
.compat_from_user = connmark_tg_compat_from_user_v0,
.compat_to_user = connmark_tg_compat_to_user_v0,
#endif
.me = THIS_MODULE
},
{
.name = "CONNMARK",
.revision = 1,
.family = AF_INET,
.checkentry = connmark_tg_check,
.target = connmark_tg,
.targetsize = sizeof(struct xt_connmark_tginfo1),
.destroy = connmark_tg_destroy,
.me = THIS_MODULE,
},
{
.name = "CONNMARK",
.revision = 1,
.family = AF_INET6,
.checkentry = connmark_tg_check,
.target = connmark_tg,
.targetsize = sizeof(struct xt_connmark_tginfo1),
.destroy = connmark_tg_destroy,
.me = THIS_MODULE,
},
};

static int __init connmark_tg_init(void)
Expand Down

0 comments on commit 0dc8c76

Please sign in to comment.