Re: pcap_lookupdev returning NULL

[Guy Harris via tcpdump-workers <tcpdump-workers () lists tcpdump org>]

> --- Begin Message ---
>
>
> From: Guy Harris <gharris () sonic net>
>
> Date: Wed, 4 Nov 2020 23:10:21 -0800
>
> On Nov 4, 2020, at 10:26 PM, Vaughan Wickham <vw () zen net au> wrote:
>
> > In regards to your latest comments regarding
> >
> > sudo setcap cap_net_raw,cap_net_admin+eip {your program}
> >
> > Are you saying that I need to compile my program and then start the compiled version with these arguments, from a 
> > terminal?
>
> No.
>
> You need to compile your program (within the IDE or on the command line), execute, on the command line, the command
>
>         sudo setcap cap_net_raw,cap_net_admin+eip {your program}
>
> where {your program} is the path to the executable that was built, and then you can run the program from the command 
> line or from the IDE.
>
> > Alternatively, while I've been happy using CentOS as a development environment up until now. As I'm planning on doing 
> > some work with pcap; if there is a "better" distro for doing pcap development I'm more than happy to build another 
> > development system using whatever flavour is easiest to develop with.
>
> Note that, as I said, getting a newer version of libpcap will *not* remove the requirement that you run your program 
> with special privileges; all it means is that pcap_lookupdev() will not require the special privileges, but if you plan 
> to *open* the device that it returns, your program will have to run with, at minimum, the cap_net_raw privileges.
>
> And all that choosing a distribution other than CentOS will do is perhaps change the libpcap version.
>
> > Basically I would like to be able build and execute within the IDE.
>
> Unless you can arrange that the IDE run a special command, *as root*, as part of the build process, you won't be able 
> to do everything within the IDE>
>
> The command in question is "setcap cap_net_raw,cap_net_admin+eip {the program that was built}".  It will have to ask 
> you for root privileges, which means that, if you want to avoid the command line, the IDE will have to run some GUI 
> program that asks for your password, or the password of somebody with rights to run a program as root (that's what 
> sudo, on the command line, does, but I don't know whether any version of sudo can do a GUI prompt when not run on the 
> command line) and then run a command as root.
>
> You will also have to have whatever privileges sudo, or the GUI program, requires you to have in order for it to allow 
> you to run a program as root.
>
> --- End Message ---
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