Re: Libpcap - pcapfindalldevs

[Johan Mazel <johan.mazel () gmail com>]

Hi
The problem is during the execution of the pcap_findalldevs command.
As I explained it (maybe not clearly enough), I can't get the return code of
this command, the program simply crash without seding a return code.

I know that for sure because I tried to do like this:
cout << "test" << endl;
result = pcap_findalldevs(&found_
cout << "test" << endl;
devices, errbuf);
if(result < 0)
{
        FindAllDevsException myFindAllDevsException(errbuf);
        cout << "Scan error" << endl;
        throw(myFindAllDevsException);
}

And there is only one "test" that is displayed.

Your solution would be ok if I could get the return code but unfortunately,
that is not the case.

Thanks for the help anyway.

Johan

2009/2/2 Benoit <benpaka.spam () gmail com>

> Yeah this is true,
> however you could try a simple loop on the interface, If there are NULL you
> must run as root.
>
>    /* Retrieve the device list on the local machine */
>    if (pcap_findalldevs(&alldevs, errbuf) == -1) {
>        printf("Error in pcap_findalldevs: %s\n", errbuf);
>        return -1;
>    }
>
>    for(d=alldevs; d; d=d->next)
>    {
>        printf("\t%d. %s\n", ++i, d->name);
>
> #ifdef WIN32
>        if (d->description)
>            printf(" (%s)\n", d->description);
>        else
>            printf(" (No description available)\n");
> #endif
>    }
>
>
>    if (i==0)
>    {
> #ifdef WIN32
>        fprintf(stderr," \tNo interfaces found! Exiting.\n");
> #else
>        fprintf(stderr," \tThis software must be run as root: No interfaces
> found!");
> #endif
>        exit(EXIT_FAILURE);
>    }
>
>
>
> --
> Benoit RAT
> www.neub.co.nr
>
>
> On Mon, Feb 2, 2009 at 2:39 PM, Johan Mazel <johan.mazel () gmail com> wrote:
>
> > Hi
> > I'm trying to use pcap_findalldevs in order to scan the device available
> on
> > my host to capture.
> >
> > My code (in C++) looks like that:
> > result = pcap_findalldevs(&found_devices, errbuf);
> > if(result < 0)
> > {
> >        FindAllDevsException myFindAllDevsException(errbuf);
> >        cout << "Scan error" << endl;
> >        throw(myFindAllDevsException);
> > }
> >
> > My problem is that when I'm not running the program as root, I got the
> > "Erreur de bus" in French (or "Bus Error" in english I guess) and my
> > program
> > suddenly stops.
> > And it looks like I cannot catch the error through the value of result.
> >
> > The pcap manpage say for pcap_findalldevs:
> > -1 is returned on failure, in which case errbuf is filled  in  with  an
> > appropriate error message; 0 is returned on success.
> > Apparently, this case of failure do not include the fact that the program
> > might not be runned as root.
> >
> > My question is the following one, is there anyway to catch this error ?
> >
> > Thanks in adavnce for the help.
> > Johan
> > -
> > This is the tcpdump-workers list.
> > Visit https://cod.sandelman.ca/ to unsubscribe.
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