[dev-serveez] SO_BINDTODEVICE investigations

[stefan]

Hello list,

The `man 7 socket' tells us about a SO_BINDTODEVICE.  I tried to apply
this feature to Serveez.  Unfortunately I came not to far...

 * You must have root priviledges to use setsockopt(SO_BINDTODEVICE).
 * I cannot connect() to the listener (with or without an extra bind()).
 * What should be the correct order? Maybe:
   1) socket()
   2) bind() (What address?)
   3) setsockopt(SO_BINDTODEVICE)
   4) listen()
 * With this order the poll() loop does not drop out to signal activity on
   the listener socket.
 * Maybe select() does?
 * Does the feature really support IP address switches on a device?  If
   so, to what address should we bind()?

Next I played around a bit with my PCMCIA cards.  I am using `cardctrl
scheme <scheme-name>' to switch my network.  Serveez tells me the correct
IP addresses (serveez -i).  But when I switch from scheme `raimi' to
`clean'  it still shows Raimi's eth0 interface and Serveez is able 
to bind to this address although `ifconfig' does not know about it.
Finally when I plug out and in again my PCMCIA card the interface
disappears also in Serveez.

This behaviour shows that we actually cannot implement a correct algorithm
for switching interface addresses... [In fact: How should a user space
program if the kernel does not?]

Cheers,
        address@hidden