sendmsg_nonblock with exception: false gobbling all errors

[HoneyryderChuck]

Reproducible with:

require "socket"

host = "fe80::1213:31ff:fe67:8b94"
ip = IPAddr.new(host)
udp  = UDPSocket.new(ip.family)

puts udp.sendmsg_nonblock("bla", 0, Socket.sockaddr_in(53, host), exception: false)

In CRuby, this raises No route to host - sendmsg(2) (Errno::EHOSTUNREACH), whereas in truffleruby, it return :wait_writable.

Bottom line is, connectivity errors shouldn't be gobbled.

Observed this behaviour with 21.1.0

[eregon]

@HoneyryderChuck Trying that script (+ require 'ipaddr') on CRuby I get:

$ ruby -v sendmsg.rb
ruby 2.7.3p183 (2021-04-05 revision 6847ee089d) [x86_64-linux]
3

And the same on truffleruby-dev and 21.1.0.

[HoneyryderChuck]

Probably because your IPv6 connectivity works better (kudos to your ISP provider 😂 ).

Maybe try it out with some other unreachable IP?

[HoneyryderChuck]

You can set the following ip table rule:

ip route add unreachable 192.168.2.1

And use that IP. Also doable from within truffleruby's docker container.

[eregon]

Thanks, I could reproduce with that, fix coming.