player: Drop long-disabled code to resolve IP addresses
Disabled since commit
32fac04 (v4.2.13) because it could at the time
use more stack space than we provided. Additional issues: code still
uses obsolete gethostbyaddr() rather than getnameinfo(), and we
provide only 512 bytes for host names instead of the customary
NI_MAXHOST (1025) bytes.
All three issues would be easy enough to fix. What's not so easy is
to avoid blocking on the synchronous DNS lookup. Without that,
connecting repeatedly from a range of addresses with slow reverse
lookup could conceivably be employed as a denial of service attack.
We've been living without reverse lookup for close to ten years. Bury
the corpse, and move on.
Bonus: sizeof(struct natstr) is cut in half.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>