+# IPv4 / IPv6 checker
+my $have_IPv4 = -1;
+my $have_IPv6 = 1;
+my $IP_factory;
+sub check_IP {
+ my $listenaddress = shift;
+
+ eval {
+ require IO::Socket::IP;
+ my $s = IO::Socket::IP->new(
+ LocalAddr => $listenaddress,
+ LocalPort => 0,
+ Listen=>1,
+ );
+ $s or die "\n";
+ $s->close();
+ };
+ if ($@ eq "") {
+ return 1;
+ }
+
+ eval {
+ require IO::Socket::INET6;
+ my $s = IO::Socket::INET6->new(
+ LocalAddr => $listenaddress,
+ LocalPort => 0,
+ Listen=>1,
+ );
+ $s or die "\n";
+ $s->close();
+ };
+ if ($@ eq "") {
+ return 1;
+ }
+
+ eval {
+ require IO::Socket::INET;
+ my $s = IO::Socket::INET->new(
+ LocalAddr => $listenaddress,
+ LocalPort => 0,
+ Listen=>1,
+ );
+ $s or die "\n";
+ $s->close();
+ };
+ if ($@ eq "") {
+ return 1;
+ }
+
+ return 0;
+}
+
+sub have_IPv4 {
+ if ($have_IPv4 < 0) {
+ $have_IPv4 = check_IP("127.0.0.1");
+ }
+ return $have_IPv4;
+}
+
+sub have_IPv6 {
+ if ($have_IPv6 < 0) {
+ $have_IPv6 = check_IP("::1");
+ }
+ return $have_IPv6;
+}
+
+