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Commit 472a73e0 authored by Jack Ma's avatar Jack Ma Committed by Pablo Neira Ayuso
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netfilter: xt_conntrack: Support bit-shifting for CONNMARK & MARK targets. 



This patch introduces a new feature that allows bitshifting (left
and right) operations to co-operate with existing iptables options.

Reviewed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarJack Ma <jack.ma@alliedtelesis.co.nz>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent d72133e6

include/uapi/linux/netfilter/xt_connmark.h

+10 −0
Original line number Diff line number Diff line
@@ -19,11 +19,21 @@ enum { 
	XT_CONNMARK_RESTORE

};



enum {

	D_SHIFT_LEFT = 0,

	D_SHIFT_RIGHT,

};



struct xt_connmark_tginfo1 {

	__u32 ctmark, ctmask, nfmask;

	__u8 mode;

};



struct xt_connmark_tginfo2 {

	__u32 ctmark, ctmask, nfmask;

	__u8 shift_dir, shift_bits, mode;

};



struct xt_connmark_mtinfo1 {

	__u32 mark, mask;

	__u8 invert;

net/netfilter/xt_connmark.c

+60 −17
Original line number Diff line number Diff line
@@ -36,9 +36,10 @@ MODULE_ALIAS("ipt_connmark"); 
MODULE_ALIAS("ip6t_connmark");



static unsigned int

connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)

connmark_tg_shift(struct sk_buff *skb,

		const struct xt_connmark_tginfo1 *info,

		u8 shift_bits, u8 shift_dir)

{

	const struct xt_connmark_tginfo1 *info = par->targinfo;

	enum ip_conntrack_info ctinfo;

	struct nf_conn *ct;

	u_int32_t newmark;
@@ -50,6 +51,10 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 
	switch (info->mode) {

	case XT_CONNMARK_SET:

		newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;

		if (shift_dir == D_SHIFT_RIGHT)

			newmark >>= shift_bits;

		else

			newmark <<= shift_bits;

		if (ct->mark != newmark) {

			ct->mark = newmark;

			nf_conntrack_event_cache(IPCT_MARK, ct);
@@ -58,6 +63,10 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 
	case XT_CONNMARK_SAVE:

		newmark = (ct->mark & ~info->ctmask) ^

			  (skb->mark & info->nfmask);

		if (shift_dir == D_SHIFT_RIGHT)

			newmark >>= shift_bits;

		else

			newmark <<= shift_bits;

		if (ct->mark != newmark) {

			ct->mark = newmark;

			nf_conntrack_event_cache(IPCT_MARK, ct);
@@ -66,13 +75,33 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 
	case XT_CONNMARK_RESTORE:

		newmark = (skb->mark & ~info->nfmask) ^

			  (ct->mark & info->ctmask);

		if (shift_dir == D_SHIFT_RIGHT)

			newmark >>= shift_bits;

		else

			newmark <<= shift_bits;

		skb->mark = newmark;

		break;

	}



	return XT_CONTINUE;

}



static unsigned int

connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)

{

	const struct xt_connmark_tginfo1 *info = par->targinfo;



	return connmark_tg_shift(skb, info, 0, 0);

}



static unsigned int

connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)

{

	const struct xt_connmark_tginfo2 *info = par->targinfo;



	return connmark_tg_shift(skb, (const struct xt_connmark_tginfo1 *)info,

				 info->shift_bits, info->shift_dir);

}



static int connmark_tg_check(const struct xt_tgchk_param *par)

{

	int ret;
@@ -119,7 +148,8 @@ static void connmark_mt_destroy(const struct xt_mtdtor_param *par) 
	nf_ct_netns_put(par->net, par->family);

}



static struct xt_target connmark_tg_reg __read_mostly = {

static struct xt_target connmark_tg_reg[] __read_mostly = {

	{

		.name           = "CONNMARK",

		.revision       = 1,

		.family         = NFPROTO_UNSPEC,
@@ -128,6 +158,17 @@ static struct xt_target connmark_tg_reg __read_mostly = { 
		.targetsize     = sizeof(struct xt_connmark_tginfo1),

		.destroy        = connmark_tg_destroy,

		.me             = THIS_MODULE,

	},

	{

		.name           = "CONNMARK",

		.revision       = 2,

		.family         = NFPROTO_UNSPEC,

		.checkentry     = connmark_tg_check,

		.target         = connmark_tg_v2,

		.targetsize     = sizeof(struct xt_connmark_tginfo2),

		.destroy        = connmark_tg_destroy,

		.me             = THIS_MODULE,

	}

};



static struct xt_match connmark_mt_reg __read_mostly = {
@@ -145,12 +186,14 @@ static int __init connmark_mt_init(void) 
{

	int ret;



	ret = xt_register_target(&connmark_tg_reg);

	ret = xt_register_targets(connmark_tg_reg,

				  ARRAY_SIZE(connmark_tg_reg));

	if (ret < 0)

		return ret;

	ret = xt_register_match(&connmark_mt_reg);

	if (ret < 0) {

		xt_unregister_target(&connmark_tg_reg);

		xt_unregister_targets(connmark_tg_reg,

				      ARRAY_SIZE(connmark_tg_reg));

		return ret;

	}

	return 0;
@@ -159,7 +202,7 @@ static int __init connmark_mt_init(void) 
static void __exit connmark_mt_exit(void)

{

	xt_unregister_match(&connmark_mt_reg);

	xt_unregister_target(&connmark_tg_reg);

	xt_unregister_target(connmark_tg_reg);

}



module_init(connmark_mt_init);