8293842: IPv6-only systems throws UnsupportedOperationException for several socket/TCP options

Co-authored-by: Martin Buchholz <martin@openjdk.org>
Reviewed-by: djelinski, dfuchs

Author: Man Cao

src/java.base/share/native/libnet/net_util.c

@@ -30,7 +30,7 @@
 
 int IPv4_supported();
 int IPv6_supported();
-int reuseport_supported();
+int reuseport_supported(int ipv6_available);
 
 static int IPv4_available;
 static int IPv6_available;
@@ -80,7 +80,7 @@ DEF_JNI_OnLoad(JavaVM *vm, void *reserved)
     IPv6_available = IPv6_supported() & (!preferIPv4Stack);
 
     /* check if SO_REUSEPORT is supported on this platform */
-    REUSEPORT_available = reuseport_supported();
+    REUSEPORT_available = reuseport_supported(IPv6_available);
     platformInit();
 
     return JNI_VERSION_1_2;

src/java.base/unix/native/libnet/net_util_md.c

@@ -187,12 +187,16 @@ jint  IPv6_supported()
 }
 #endif /* DONT_ENABLE_IPV6 */
 
-jint reuseport_supported()
+jint reuseport_supported(int ipv6_available)
 {
     /* Do a simple dummy call, and try to figure out from that */
     int one = 1;
     int rv, s;
-    s = socket(PF_INET, SOCK_STREAM, 0);
+    if (ipv6_available) {
+        s = socket(PF_INET6, SOCK_STREAM, 0);
+    } else {
+        s = socket(PF_INET, SOCK_STREAM, 0);
+    }
     if (s < 0) {
         return JNI_FALSE;
     }

src/java.base/windows/native/libnet/net_util_md.c

@@ -235,7 +235,7 @@ jint  IPv6_supported()
     return JNI_TRUE;
 }
 
-jint reuseport_supported()
+jint reuseport_supported(int ipv6_available)
 {
     /* SO_REUSEPORT is not supported on Windows */
     return JNI_FALSE;

src/jdk.net/linux/native/libextnet/LinuxSocketOptions.c

@@ -54,9 +54,15 @@ static jint socketOptionSupported(jint level, jint optname) {
     jint one = 1;
     jint rv, s;
     socklen_t sz = sizeof (one);
-    s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+    /* First try IPv6; fall back to IPv4. */
+    s = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP);
     if (s < 0) {
-        return 0;
+        if (errno == EPFNOSUPPORT || errno == EAFNOSUPPORT) {
+            s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+        }
+        if (s < 0) {
+            return 0;
+        }
     }
     rv = getsockopt(s, level, optname, (void *) &one, &sz);
     if (rv != 0 && errno == ENOPROTOOPT) {

src/jdk.net/macosx/native/libextnet/MacOSXSocketOptions.c

@@ -48,9 +48,15 @@ DEF_STATIC_JNI_OnLoad
 static jint socketOptionSupported(jint sockopt) {
     jint one = 1;
     jint rv, s;
-    s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+    /* First try IPv6; fall back to IPv4. */
+    s = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
     if (s < 0) {
-        return 0;
+        if (errno == EPFNOSUPPORT || errno == EAFNOSUPPORT) {
+            s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+        }
+        if (s < 0) {
+            return 0;
+        }
     }
     rv = setsockopt(s, IPPROTO_TCP, sockopt, (void *) &one, sizeof (one));
     if (rv != 0 && errno == ENOPROTOOPT) {