[xio-user] XIO client-side interface binding logic?
mulmo at univa.com
Fri Nov 17 04:41:14 CST 2006
Does the XIO (TCP) client honor GLOBUS_HOSTNAME when
selecting what address to bind() a socket to?
I have a VLAN overlayed on a normal network the two endpoints
happen to have a connection as well. The two connections share
the same physical network card on the computers (eth0 and eth0:1)
-- the traffic then splits into separate paths later depending
on the destination IP.
This means that in order to get traffic over my special route,
I need to e.g. do "ping -I <src ip>", otherwise the src IP will
be the public IP, not the VLAN IP, which results in assymmetric
routing: the reply will go across the public network on the way
This is by design: everything should be routed on the "public"
network by default, and only selected traffic for certain
applications should go on the VLAN. On such application is
the one I have written on top of XIO.
At first I thought I could control the src IP by using
GLOBUS_HOSTNAME, but that does not seem to be the case: as far
as I can tell, the src IP will always be the public one. In my
case, this results in assymmetric routing.
I understand this is an uncommon and rather obscure setup, but
it made me wonder if I just have goofed up, have missed setting
some XIO attribute, or whether XIO clients don't look at
GLOBUS_HOSTNAME at all when calling bind()?
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