On Nov 18, 2024, at 11:54 AM, Denis Ovsienko <de...@ovsienko.info> wrote:
> The current approach in libpcap is such that an application at some
> point tries to activate a device, and if the device does not support
> capturing packets, pcap_activate() fails with the
> PCAP_ERROR_CAPTURE_NOTSUP error code. One drawback of this is that the
> application has no means to tell a capture-capable device without
> trying to activate it, another is that telling an inject-capable device
> takes trying to use the device after pcap_activate() succeeds. It would
> be useful to have a shorter feedback loop for these capabilities.
So "even neither" devices could either not be shown in pcap_findalldevs() or be
shown with both of the "not supported" flags set. One argument for showing it
might be that, if the device isn't shown, a user might have reason to expect it
to be there, and report this as "why isn't device XXX not showing up?", which
doesn't indicate what the problem is, and turns into a question-and-answer
session, whereas if the device is present, the user will see the device,
attempt to capture or inject on it, and get a "{capturing,injecting} traffic
isn't supported on this device" error, and if they report *that*, at least it's
known what the problem is, shortening the Q&A session and getting an answer
more quickly.
> Does it make sense?
Sounds good to me.
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