Bug 99191

Summary: ARP monitoring with bonding module uses interface alias for ARP request
Product: Networking Reporter: benl (lessani)
Component: OtherAssignee: Stephen Hemminger (stephen)
Status: NEW ---    
Severity: normal CC: kongjianjun, szg00000
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: All Subsystem:
Regression: No Bisected commit-id:

Description benl 2015-05-29 17:59:33 UTC 
When using arp_ip_target combined with arp_validate to verify the connectivity status of a bond, the wrong IP address is used as the source of the request if multiple IP aliases are assigned to the bond0.

Example 1.

bond0   - 10.0.0.5/24 (WAN)
bond0:1 - 10.0.1.5/24 (LAN)
arp_validate - all
arp_ip_target - 10.0.0.1

Expected result: ARP, Request who-has 10.0.0.1 tell 10.0.0.5

Actual result:   ARP, Request who-has 10.0.0.1 tell 10.0.1.5

Issue:           The Layer 3 switch responsible for replying to the ARP request does not have the local interface of 10.0.1.5 configured, so the ARP request goes unanswered.

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My expectation is that the bonding driver would use the primary IP on the bond0 interface, not a secondary IP. The solution being to be able to specify which IP the ARP should originate from in a scenario where bondX has multiple IPs assigned.

Mangling the packet in/out using arptables does not achieve the desired effect.