[ipv6] RFR: 8223532: Don't try creating IPv4 sockets in NetworkInterface.c if IPv4 is not supported

[Chris Hegarty]

Arthur,

> On 8 May 2019, at 18:33, Arthur Eubanks <aeubanks at google.com> wrote:
> 
> Reverted changes in net_util.c.
> Also, webrev.00 would create an IPv6 socket even if creating the IPv4 socket was successful. Fixed. (My very first revision had this same issue, which I thought I had fixed before sending it out. Tricky if statements have been cleaned up to make this less likely to happen again in the future.)
> 
> http://cr.openjdk.java.net/~aeubanks/8223532/webrev.01/

The following is Solaris specific code:

1630                 sock = socket(AF_INET6, SOCK_DGRAM, 0)

It is missing a trailing semi-colon, so does not compile on Solaris.

Also the else block where this code exists should probably be:
 
   else if (ipv6_available()) {

   , since it creates an AF_NET6 socket.

I’ll run some tests.

-Chris.