bridge: change BR_GROUPFWD_RESTRICTED to allow forwarding of LLDP frames (784b58a3) · Commits · 戴 / test

BR_GROUPFWD_RESTRICTED bitmask restricts users from setting values to /sys/class/net/brX/bridge/group_fwd_mask that allow forwarding of some IEEE 802.1D Table 7-10 Reserved addresses: (MAC Control) 802.3 01-80-C2-00-00-01 (Link Aggregation) 802.3 01-80-C2-00-00-02 802.1AB LLDP 01-80-C2-00-00-0E Change BR_GROUPFWD_RESTRICTED to allow to forward LLDP frames and document group_fwd_mask. e.g. echo 16384 > /sys/class/net/brX/bridge/group_fwd_mask allows to forward LLDP frames. This may be needed for bridge setups used for network troubleshooting or any other scenario where forwarding of LLDP frames is desired (e.g. bridge connecting a virtual machine to real switch transmitting LLDP frames that virtual machine needs to receive). Tested on a simple bridge setup with two interfaces and host transmitting LLDP frames on one side of this bridge (used lldpd). Setting group_fwd_mask as described above lets LLDP frames traverse bridge. Signed-off-by:

Bernhard Thaler <bernhard.thaler@wvnet.at> Signed-off-by:

David S. Miller <davem@davemloft.net>

Documentation/ABI/testing/sysfs-class-net

+19 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,25 @@ Description:
		Format is a string, e.g: 00:11:22:33:44:55 for an Ethernet MAC
		address.

		What: /sys/class/net/<bridge iface>/bridge/group_fwd_mask
		Date: January 2012
		KernelVersion: 3.2
		Contact: netdev@vger.kernel.org
		Description:
		Bitmask to allow forwarding of link local frames with address
		01-80-C2-00-00-0X on a bridge device. Only values that set bits
		not matching BR_GROUPFWD_RESTRICTED in net/bridge/br_private.h
		allowed.
		Default value 0 does not forward any link local frames.

		Restricted bits:
		0: 01-80-C2-00-00-00 Bridge Group Address used for STP
		1: 01-80-C2-00-00-01 (MAC Control) 802.3 used for MAC PAUSE
		2: 01-80-C2-00-00-02 (Link Aggregation) 802.3ad

		Any values not setting these bits can be used. Take special
		care when forwarding control frames e.g. 802.1X-PAE or LLDP.

		What: /sys/class/net/<iface>/broadcast
		Date: April 2005
		KernelVersion: 2.6.12

net/bridge/br_private.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -33,8 +33,8 @@

		/* Control of forwarding link local multicast */
		#define BR_GROUPFWD_DEFAULT 0
		/* Don't allow forwarding control protocols like STP and LLDP */
		#define BR_GROUPFWD_RESTRICTED 0x4007u
		/* Don't allow forwarding of control protocols like STP, MAC PAUSE and LACP */
		#define BR_GROUPFWD_RESTRICTED 0x0007u
		/* The Nearest Customer Bridge Group Address, 01-80-C2-00-00-[00,0B,0C,0D,0F] */
		#define BR_GROUPFWD_8021AD 0xB801u

Admin message