Add v6Only named argument to ServerSocket and etc.

runtime/bin/socket_linux.cc

Index: runtime/bin/socket_linux.cc
diff --git a/runtime/bin/socket_linux.cc b/runtime/bin/socket_linux.cc
index e881f5d7b20a57ec15058691d4d9478608ae5956..cfc9b12b1122811472857791ee6af299c7f009ef 100644
--- a/runtime/bin/socket_linux.cc
+++ b/runtime/bin/socket_linux.cc
@@ -207,7 +207,8 @@ SocketAddresses* Socket::LookupAddress(const char* host,
 
 intptr_t ServerSocket::CreateBindListen(RawAddr addr,
                                         intptr_t port,
-                                        intptr_t backlog) {
+                                        intptr_t backlog,
+                                        bool v6_only) {
   intptr_t fd;
 
   fd = TEMP_FAILURE_RETRY(socket(addr.ss.ss_family, SOCK_STREAM, 0));
@@ -220,7 +221,7 @@ intptr_t ServerSocket::CreateBindListen(RawAddr addr,
       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)));
 
   if (addr.ss.ss_family == AF_INET6) {
-    optval = 0;
+    optval = v6_only ? 1 : 0;

[Søren Gjesse, 2013/05/01 12:27:47]

Isn't the default 1? So we only need to set it if v6_only is false?

[Anders Johnsen, 2013/05/01 12:30:05]

It's changeable (0 on my machine).

     TEMP_FAILURE_RETRY(
         setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &optval, sizeof(optval)));
   }