Socket.udp_server_sockets

# File tmp/rubies/ruby-3.1.3/ext/socket/lib/socket.rb, line 884
def self.udp_server_sockets(host=nil, port)
  last_error = nil
  sockets = []

  ipv6_recvpktinfo = nil
  if defined? Socket::AncillaryData
    if defined? Socket::IPV6_RECVPKTINFO # RFC 3542
      ipv6_recvpktinfo = Socket::IPV6_RECVPKTINFO
    elsif defined? Socket::IPV6_PKTINFO # RFC 2292
      ipv6_recvpktinfo = Socket::IPV6_PKTINFO
    end
  end

  local_addrs = Socket.ip_address_list

  ip_list = []
  Addrinfo.foreach(host, port, nil, :DGRAM, nil, Socket::AI_PASSIVE) {|ai|
    if ai.ipv4? && ai.ip_address == "0.0.0.0"
      local_addrs.each {|a|
        next unless a.ipv4?
        ip_list << Addrinfo.new(a.to_sockaddr, :INET, :DGRAM, 0);
      }
    elsif ai.ipv6? && ai.ip_address == "::" && !ipv6_recvpktinfo
      local_addrs.each {|a|
        next unless a.ipv6?
        ip_list << Addrinfo.new(a.to_sockaddr, :INET6, :DGRAM, 0);
      }
    else
      ip_list << ai
    end
  }
  ip_list.uniq!(&:to_sockaddr)

  if port == 0
    sockets = ip_sockets_port0(ip_list, false)
  else
    ip_list.each {|ip|
      ai = Addrinfo.udp(ip.ip_address, port)
      begin
        s = ai.bind
      rescue SystemCallError
        last_error = $!
        next
      end
      sockets << s
    }
    if sockets.empty?
      raise last_error
    end
  end

  sockets.each {|s|
    ai = s.local_address
    if ipv6_recvpktinfo && ai.ipv6? && ai.ip_address == "::"
      s.setsockopt(:IPV6, ipv6_recvpktinfo, 1)
    end
  }

  if block_given?
    begin
      yield sockets
    ensure
      sockets.each(&:close) if sockets
    end
  else
    sockets
  end
end