DLPI device but don't have permission to put the interface in
promiscuous mode; some systems using DLPI work that way.
Change the libdlpi code to return a warning if you *are* using
physical promiscuous mode and you fail to turn on SAP promiscuous mode,
not if you *aren't* using physical promiscuous mode and you fail to turn
on SAP promiscuous mode; that matches with the no-libdlpi code does, and
matches what the comment says.
Pull dlattachreq up into dl_doattach().
isn't up, so applications can report that differently from a generic
error (the latter could mean there's a bug somewhere in libpcap).
When capturing on a device without mmap on Linux, ignore ENETDOWN, so
that we can continue to capture traffic if the interface goes down and
comes back up again; comments in the kernel indicate that we'll just
block waiting for packets if we try to receive from a socket that
delivered ENETDOWN, and, if we're using a memory-mapped buffer, we won't
even get notified of "network down" events.
know that..."; currently, only pcap_activate() returns them, but we
might want some more warning returns for some other calls, such as the
ones that set filters. It's a little cleaner than "clear out the error
message buffer and, if it's not empty after a successful return, it has
a warning", and a little cleaner than spewing a warning to the standard
error (as that might not be visible to the user if they're running a GUI
application).
that often means "sorry, this platform requires you to run as root or to
somehow tweak the system to give you capture privileges", and
applications might want to explain that in a way that does a better job
of letting the user know what they have to do.
Try to return or PCAP_ERROR_PERM_DENIED for open errors, rather than
just returning PCAP_ERROR, so that the application can, if it chooses,
try to explain the error better (as those two errors are the ones that
don't mean "there's probably some obscure OS or libpcap problem", but
mean, instead, "you made an error" or "you need to get permission to
capture").
Check for monitor mode *after* checking whether the device exists in the
first place; a non-existent device doesn't support monitor mode, but
that's because it doesn't, well, exist, and the latter would be a more
meaningful error.
Have pcap_open_live() supply an error message for return values other
than PCAP_ERROR, PCAP_ERROR_NO_SUCH_DEVICE, and PCAP_ERROR_PERM_DENIED -
those all supply error strings (PCAP_ERROR because it's for various OS
problems that might require debugging, and the other two because there
might be multiple causes).
Guy Harris