Allow UDP broadcasts

[captain0xff]

SDL2_net had a way to enable or disable UDP broadcasts

SDL_net/src/SDLnetUDP.c

Line 185 in 8e1e4bf

#ifdef SO_BROADCAST

it will be nice to also have them in SDL3_net.

[icculus]

So the problem is broadcasts are an IPv4 subnet thing. This concept is entirely gone from IPv6, where they have something called "anycast" addresses, but it requires configuring entire groups of computers to use it...it's not like IPv4 where you just send a packet to the .255 address and things that care listen for it.

[captain0xff]

Oh, I was not aware of this. Ig I will have to find a better solution for server discovery. Anyways, thank you for answering. You can close the issue if you want.

[icculus]

So Wikipedia has this to say:

Internet Protocol version 6 (IPv6) does not implement this method of broadcast, and therefore does not define broadcast addresses. Instead, IPv6 uses multicast addressing to the all-hosts multicast group. No IPv6 protocols are defined to use the all-hosts address, though; instead, they send and receive on particular link-local multicast addresses. This results in higher efficiency because network hosts can filter traffic based on multicast address and do not need to process all broadcasts or all-hosts multicasts.

...so maybe this is doable? I'll leave this open for now until I research more.

[captain0xff]

Found an multicast example that seems to work for me.
https://gist.github.com/hostilefork/f7cae3dc33e7416f2dd25a402857b6c6