As reported in issue #1654, using select to test for a (non-blocking) connection success crashes on FreeBSD when the number of opened file descriptor is higher than FDSET_SIZE.
Instead of returning with an error in that case, this commit uses poll instead that's not limited to the number of opened file descriptors, preventing an out-of-bound write.
socket() with SOCK_NONBLOCK (O_NONBLOCK) seems not to be possible on MacOS, it
yields 'Protocol wrong type for socket'. Switch to using fcntl() and O_NONBLOCK
instead, hopefully works better cross-platform.
Closes#1644
Necessary to clear the resolver list on client restart, since especially
r->resolver becomes invalid when mdns_client is freed.
Also drop freeing of libevent watches and timers on deinit, it is not
necessary, Avahi will do it.
Some remotes don't respond as expected to the test. Retune will give connection
refused, because the test is made too quickly, before the service is running.
Even if we delay the test it won't work because Retune crashes.
Since the false mdns advertisements are only seen on Airplay, we only do the
test there.
The connection test would not catch "No route to host", as this is returned
through the value-result buffer.
This fix might partially solve issue #498.
Avahi gives us several ipv6 addresses for an ATV4 that aren't actually
connectable. Here we simply try to make a connection to the address,
and if it is not possible within a timeout we ignore the announcement.
We also now don't start a mdns record browser if the address from the
resolver passes the connection test and isn't link-local.
Added configure checks needed to detect missing functions on OSX
Added compat clock functions using clock_get_time on OSX
Added compat timer functions using clock_gettime and setitimer on OSX
Added byteswap functions on OSX
Added a real config.rpath
Fixed build date calc for BSD
Require some needed headers at configure time
Correctly check libav functions using pkg-config flags
Made checks for some Linux features available on other ports
Fixed porting issue with antlr dep files
Added default HOST_NAME_MAX if not defined
Added missing libav header
The service resolver delivers a single IP address that doesn't always suit
our needs. To get all the addresses advertised, we have to look at the RRs
through the record browser; we can then apply our filters and extract the
addresses that fit.
Discard IPv4 link-local addresses; IPv4LL doesn't work on most systems, so the
address are effectively useless to us.
Turn IPv6 link-local addresses into scoped addresses by appending the interface
name to the address.
