Re: [clearview-discuss] libdlpi with libpcap

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

On Feb 1, 2008, at 12:47 PM, sagun shakya wrote:

> Sebastien Roy wrote:
> > * 118-123: I would think that in 2008, most compilers can do a  
> > better job at assigning register use than this (making every single  
> > variable a "register" variable.)  You don't have to fix this; this  
> > is more a question for those more knowledgeable than me at compiler  
> > optimization.
> Since I'm not an expert either, I wasn't sure what to do here and in  
> the new file added. I was expecting there would be some comment  
> regarding how it would be best to use them.

My comment, as per my other mail, about how it's best to use  
"register" is "it's best not to use 'register' these days".  Let the  
compiler worry about it.

> > * 130: This looks like a bug.  In the pcap-dlpi.c code, failure to  
> > enable multicast promiscuous mode does not result in a failure, but  
> > only a warning.
> Will fix, but before that I have a question,I had changed the logic  
> here in comparision to pcap-dlpi.c; in pcap-dlpi.c the logic is :
> if (promisc)
>   enable physical promiscuous mode
>   then enable multicast promiscuous mode
> else
>   enable promiscuous mode at SAP level.
>
> In pcap-libdlpi I have it to be, :
> if (promisc)
>   enable physical promiscuous mode
> else
>   enable multicast promiscuous mode
>
> enable promiscuous mode at SAP level.
>
> I guessthe logic should be as in pcap-dlpi.c?

Perhaps.  I don't know what the comment in the code sample from my  
previous mail:

                /*
                ** Try to enable multicast (you would have thought
                ** promiscuous would be sufficient). (Skip if using
                ** HP-UX or SINIX) (Not necessary on send FD)
                */

is referring to.  pcap-dlpi.c supports several platforms:

	SunOS 5.x, for various values of "x" dating back at least to 2, given  
that there's code to work around a bufmod bug that checks for SunOS  
5.2 as well as 5.3.0 and 5.3.1;

        HP-UX 9, 10, and 11;

        AIX (although, by default, BPF is used);

        SINIX

and, for all I know, it might support some other SV-ish UN*Xes as  
well.  I don't know which versions of which OSes had that issue,  
wherein you had to turn on DL_PROMISC_MULTI as well as DL_PROMISC_PHYS  
(that code predates my involvement with libpcap - it dates back to  
libpcap 0.4).  Obviously neither HP-UX nor SINIX had it, as per the  
comment and the #ifdefs that omit the code in question on those OSes;  
I don't know if it's required by AIX, older versions of SunOS 5.x, or  
all versions of SunOS 5.x.
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