Nsock has trouble handling pcap reads on Windows

[Luis MartinGarcia <luis.mgarc () gmail com>]

Hi,

I've detected that Nsock has trouble handling pcap read events on
Windows. The thing is that on Windows, the pcap descriptor is not
selectable. Therefore, when Nsock waits for an event, with fselect(),
it does not detect new packets being captured until the fselect() call
times out and the pcap descriptor is checked for new data. This way,
if we schedule a pcap read event like this:

nsock_pcap_read_packet(nsp, pcap_nsi, pcap_event_handler, 10000, NULL)
// Timeout 10s
nsock_loop(nsp, 5000); // Timeout 5s

Nsock does not call pcap_event_handler() until the nsock_loop()  times
out after 5s, even if we captured a hundred packets in the meantime.
To solve this, we need to detect when a pcap read event has been
scheduled, and make any select() call to timeout quickly, so the pcap
descriptor can be polled often, and nsock delivers captured packets to
the application, as soon as possible.

I attach a patch that should fix this problem. Please let me know if
you have any comments.

Regards,

Luis MartinGarcia.

Attachment: polling_pcap_nsock.diff
Description:

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