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-rw-r--r--Documentation/networking/bonding.txt63
1 files changed, 63 insertions, 0 deletions
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 2c197b68baf0..334b49ef02d1 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -51,6 +51,7 @@ Table of Contents
3.4 Configuring Bonding Manually via Sysfs
3.5 Configuration with Interfaces Support
3.6 Overriding Configuration for Special Cases
+3.7 Configuring LACP for 802.3ad mode in a more secure way
4. Querying Bonding Configuration
4.1 Bonding Configuration
@@ -241,6 +242,21 @@ ad_select
This option was added in bonding version 3.4.0.
+ad_user_port_key
+
+ In an AD system, the port-key has three parts as shown below -
+
+ Bits Use
+ 00 Duplex
+ 01-05 Speed
+ 06-15 User-defined
+
+ This defines the upper 10 bits of the port key. The values can be
+ from 0 - 1023. If not given, the system defaults to 0.
+
+ This parameter has effect only in 802.3ad mode and is available through
+ SysFs interface.
+
all_slaves_active
Specifies that duplicate frames (received on inactive ports) should be
@@ -1643,6 +1659,53 @@ output port selection.
This feature first appeared in bonding driver version 3.7.0 and support for
output slave selection was limited to round-robin and active-backup modes.
+3.7 Configuring LACP for 802.3ad mode in a more secure way
+----------------------------------------------------------
+
+When using 802.3ad bonding mode, the Actor (host) and Partner (switch)
+exchange LACPDUs. These LACPDUs cannot be sniffed, because they are
+destined to link local mac addresses (which switches/bridges are not
+supposed to forward). However, most of the values are easily predictable
+or are simply the machine's MAC address (which is trivially known to all
+other hosts in the same L2). This implies that other machines in the L2
+domain can spoof LACPDU packets from other hosts to the switch and potentially
+cause mayhem by joining (from the point of view of the switch) another
+machine's aggregate, thus receiving a portion of that hosts incoming
+traffic and / or spoofing traffic from that machine themselves (potentially
+even successfully terminating some portion of flows). Though this is not
+a likely scenario, one could avoid this possibility by simply configuring
+few bonding parameters:
+
+ (a) ad_actor_system : You can set a random mac-address that can be used for
+ these LACPDU exchanges. The value can not be either NULL or Multicast.
+ Also it's preferable to set the local-admin bit. Following shell code
+ generates a random mac-address as described above.
+
+ # sys_mac_addr=$(printf '%02x:%02x:%02x:%02x:%02x:%02x' \
+ $(( (RANDOM & 0xFE) | 0x02 )) \
+ $(( RANDOM & 0xFF )) \
+ $(( RANDOM & 0xFF )) \
+ $(( RANDOM & 0xFF )) \
+ $(( RANDOM & 0xFF )) \
+ $(( RANDOM & 0xFF )))
+ # echo $sys_mac_addr > /sys/class/net/bond0/bonding/ad_actor_system
+
+ (b) ad_actor_sys_prio : Randomize the system priority. The default value
+ is 65535, but system can take the value from 1 - 65535. Following shell
+ code generates random priority and sets it.
+
+ # sys_prio=$(( 1 + RANDOM + RANDOM ))
+ # echo $sys_prio > /sys/class/net/bond0/bonding/ad_actor_sys_prio
+
+ (c) ad_user_port_key : Use the user portion of the port-key. The default
+ keeps this empty. These are the upper 10 bits of the port-key and value
+ ranges from 0 - 1023. Following shell code generates these 10 bits and
+ sets it.
+
+ # usr_port_key=$(( RANDOM & 0x3FF ))
+ # echo $usr_port_key > /sys/class/net/bond0/bonding/ad_user_port_key
+
+
4 Querying Bonding Configuration
=================================

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