Re: What's the correct new API to request pcap_linux to not open an eventfd

[Bill Fenner via tcpdump-workers <tcpdump-workers () lists tcpdump org>]

> --- Begin Message ---
>
>
> From: Bill Fenner <fenner () gmail com>
>
> Date: Fri, 20 May 2022 15:10:58 -0700
>
> On Fri, May 20, 2022 at 12:36 PM Guy Harris <gharris () sonic net> wrote:
>
> > If it's putting them in non-blocking mode, and using some
> > select/poll/epoll/etc. mechanism in a single event loop, then the right
> > name for the API is pcap_setnonblock().  There's no need for an eventfd to
> > wake up the blocking poll() if there *is* no blocking poll(), so:
> >
> >         if non-blocking mode is on before pcap_activate() is called, no
> > eventfd should be opened, and poll_breakloop_fd should be set to -1;
> >
> >         if non-blocking mode is turned on after pcap_activate() is called,
> > the eventfd should be closed, and poll_breakloop_fd should be set to -1;
> >
> >         if non-blocking mode is turned *off* afterwards, an eventfd should
> > be opened, and poll_breakloop_fd should be set to it;
> >
> >         if poll_breakloop_fd is -1, the poll() should only wait on the
> > socket FD;
> >
> > so this can be handled without API changes.
>
> Thank you for the excellent observation, Guy.  It is indeed setting
> non-block before pcap_activate().  I'll work on this plan.
>
>   Bill
>
> --- End Message ---
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