Re: libpcap: patches required for OpenSolaris/SXCE

[Guy Harris <guy () alum mit edu>]

On Dec 1, 2009, at 7:06 PM, Sebastien Roy wrote:

> > > bash-3.2# tcpdump -i bge0
> > > tcpdump: WARNING: SIOCGIFADDR: bge0: No such device or address
> >
> > This means "sorry, if you're expecting -f to work or a filter
> > containing 'ip broadcast' to work, you're going to be disappointed".
>
> Why not say exactly that?

Because pcap_lookupnet() doesn't know how to distinguish between  
"there's no such interface at all", "there is such an interface but it  
has no IPv4 address", and "something else happened".  What's the right  
way to do so on Solaris?

> > Does the errno corresponding to "No such device or address", when
> > returned by ioctl(SIOCGIFADDR), mean "this device doesn't have an
> > address of the type"?  Or can it also mean "there is no such device"?
>
> It means that there is no IP interface named bge0.

...which could mean "this device doesn't have an address of that type"  
or "there is no such device".

> But as shown in the ifconfig output, there was no IP interface named
> bge0, so it couldn't possibly have obtained a default interface of  
> bge0
> from SIOCGLIFCONF.  According to truss, in the version of libpcap  
> that I
> have, it uses libdlpi's dlpi_walk(), which is a reasonable and  
> supported
> way of obtaining the list of datalinks on Solaris.

It uses SIOCGLIFCONF *and*, if you have libdlpi, dlpi_walk().  Does  
SIOCGLIFCONF also return IPv4 and IPv6 addresses for the interface?   
If so, then using both has the advantage that you also get the  
addresses, that being what pcap_findalldevs() returns (a list of  
interfaces, each of which has 0 or more addresses).
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