Don't try to do IPV6_V6ONLY on OpenBSD either.

setsockopt(3) returns an error if passing 0 to this option (which
we do if no address family is specified when we bind to the wildcard
address, say by invoking "iperf3 -s" with no other options).  This
is because OpenBSD explicitly does not support IPv4-mapped addresses,
so even though the IPV6_V6ONLY socket options exists, it only works
with a non-zero argument.

Fixes #196.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/net.c b/src/net.c
index 28b5176..72947d3 100644
--- a/src/net.c
+++ b/src/net.c
@@ -146,9 +146,12 @@ netannounce(int domain, int proto, char *local, int port)
     /*
      * If we got an IPv6 socket, figure out if it should accept IPv4
      * connections as well.  We do that if and only if no address
-     * family was specified explicitly.
+     * family was specified explicitly.  Note that we can only
+     * do this if the IPV6_V6ONLY socket option is supported.  Also,
+     * OpenBSD explicitly omits support for IPv4-mapped addresses,
+     * even though it implements IPV6_V6ONLY.
      */
-#ifdef IPV6_V6ONLY
+#if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
     if (res->ai_family == AF_INET6 && (domain == AF_UNSPEC || domain == AF_INET6)) {
 	if (domain == AF_UNSPEC)
 	    opt = 0;