Commit 4981682c authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: bridge: optionally set indev to vlan 



if net.bridge.bridge-nf-filter-vlan-tagged sysctl is enabled, bridge
netfilter removes the vlan header temporarily and then feeds the packet
to ip(6)tables.

When the new "bridge-nf-pass-vlan-input-device" sysctl is on
(default off), then bridge netfilter will also set the
in-interface to the vlan interface; if such an interface exists.

This is needed to make iptables REDIRECT target work with
"vlan-on-top-of-bridge" setups and to allow use of "iptables -i" to
match the vlan device name.

Also update Documentation with current brnf default settings.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Acked-by: default avatarBart De Schuymer <bdschuym@pandora.be>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent ac3a546a

Documentation/networking/ip-sysctl.txt

+11 −2
Original line number Diff line number Diff line
@@ -1301,13 +1301,22 @@ bridge-nf-call-ip6tables - BOOLEAN 
bridge-nf-filter-vlan-tagged - BOOLEAN

	1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables.

	0 : disable this.

	Default: 1

	Default: 0



bridge-nf-filter-pppoe-tagged - BOOLEAN

	1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables.

	0 : disable this.

	Default: 1

	Default: 0



bridge-nf-pass-vlan-input-dev - BOOLEAN

	1: if bridge-nf-filter-vlan-tagged is enabled, try to find a vlan

	interface on the bridge and set the netfilter input device to the vlan.

	This allows use of e.g. "iptables -i br0.1" and makes the REDIRECT

	target work with vlan-on-top-of-bridge interfaces.  When no matching

	vlan interface is found, or this switch is off, the input device is

	set to the bridge interface.

	0: disable bridge netfilter vlan interface lookup.

	Default: 0



proc/sys/net/sctp/* Variables:

net/bridge/br_netfilter.c

+24 −2
Original line number Diff line number Diff line
@@ -54,12 +54,14 @@ static int brnf_call_ip6tables __read_mostly = 1; 
static int brnf_call_arptables __read_mostly = 1;

static int brnf_filter_vlan_tagged __read_mostly = 0;

static int brnf_filter_pppoe_tagged __read_mostly = 0;

static int brnf_pass_vlan_indev __read_mostly = 0;

#else

#define brnf_call_iptables 1

#define brnf_call_ip6tables 1

#define brnf_call_arptables 1

#define brnf_filter_vlan_tagged 0

#define brnf_filter_pppoe_tagged 0

#define brnf_pass_vlan_indev 0

#endif



#define IS_IP(skb) \
@@ -503,6 +505,19 @@ bridged_dnat: 
	return 0;

}



static struct net_device *brnf_get_logical_dev(struct sk_buff *skb, const struct net_device *dev)

{

	struct net_device *vlan, *br;



	br = bridge_parent(dev);

	if (brnf_pass_vlan_indev == 0 || !vlan_tx_tag_present(skb))

		return br;



	vlan = __vlan_find_dev_deep(br, vlan_tx_tag_get(skb) & VLAN_VID_MASK);



	return vlan ? vlan : br;

}



/* Some common code for IPv4/IPv6 */

static struct net_device *setup_pre_routing(struct sk_buff *skb)

{
@@ -515,7 +530,7 @@ static struct net_device *setup_pre_routing(struct sk_buff *skb) 


	nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;

	nf_bridge->physindev = skb->dev;

	skb->dev = bridge_parent(skb->dev);

	skb->dev = brnf_get_logical_dev(skb, skb->dev);

	if (skb->protocol == htons(ETH_P_8021Q))

		nf_bridge->mask |= BRNF_8021Q;

	else if (skb->protocol == htons(ETH_P_PPP_SES))
@@ -774,7 +789,7 @@ static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff *skb, 
	else

		skb->protocol = htons(ETH_P_IPV6);



	NF_HOOK(pf, NF_INET_FORWARD, skb, bridge_parent(in), parent,

	NF_HOOK(pf, NF_INET_FORWARD, skb, brnf_get_logical_dev(skb, in), parent,

		br_nf_forward_finish);



	return NF_STOLEN;
@@ -1002,6 +1017,13 @@ static ctl_table brnf_table[] = { 
		.mode		= 0644,

		.proc_handler	= brnf_sysctl_call_tables,

	},

	{

		.procname	= "bridge-nf-pass-vlan-input-dev",

		.data		= &brnf_pass_vlan_indev,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= brnf_sysctl_call_tables,

	},

	{ }

};

#endif

CRA Git | Maintained and supported by SUSTech CRA and CCSE