8290349: IP_DONTFRAGMENT doesn't set DF bit in IPv4 header

Reviewed-by: michaelm, alanb

src/java.base/share/classes/sun/net/ext/ExtendedSocketOptions.java

@@ -133,11 +133,11 @@ public abstract class ExtendedSocketOptions {
     }
 
     /** Sets the value of a socket option, for the given socket. */
-    public abstract void setOption(FileDescriptor fd, SocketOption<?> option, Object value)
+    public abstract void setOption(FileDescriptor fd, SocketOption<?> option, Object value, boolean isIPv6)
             throws SocketException;
 
     /** Returns the value of a socket option, for the given socket. */
-    public abstract Object getOption(FileDescriptor fd, SocketOption<?> option)
+    public abstract Object getOption(FileDescriptor fd, SocketOption<?> option, boolean isIPv6)
             throws SocketException;
 
     protected ExtendedSocketOptions(Set<SocketOption<?>> options) {
@@ -206,7 +206,7 @@ public abstract class ExtendedSocketOptions {
         }
 
         @Override
-        public void setOption(FileDescriptor fd, SocketOption<?> option, Object value)
+        public void setOption(FileDescriptor fd, SocketOption<?> option, Object value, boolean isIPv6)
             throws SocketException
         {
             throw new UnsupportedOperationException(
@@ -214,7 +214,7 @@ public abstract class ExtendedSocketOptions {
         }
 
         @Override
-        public Object getOption(FileDescriptor fd, SocketOption<?> option)
+        public Object getOption(FileDescriptor fd, SocketOption<?> option, boolean isIPv6)
             throws SocketException
         {
             throw new UnsupportedOperationException(

src/java.base/share/classes/sun/nio/ch/Net.java

@@ -402,9 +402,10 @@ public class Net {
 
         // only simple values supported by this method
         Class<?> type = name.type();
+        boolean isIPv6 = (family == StandardProtocolFamily.INET6);
 
         if (extendedOptions.isOptionSupported(name)) {
-            extendedOptions.setOption(fd, name, value);
+            extendedOptions.setOption(fd, name, value, isIPv6);
             return;
         }
 
@@ -451,7 +452,6 @@ public class Net {
         }
 
         boolean mayNeedConversion = (family == UNSPEC);
-        boolean isIPv6 = (family == StandardProtocolFamily.INET6);
         setIntOption0(fd, mayNeedConversion, key.level(), key.name(), arg, isIPv6);
     }
 
@@ -467,7 +467,8 @@ public class Net {
         Class<?> type = name.type();
 
         if (extendedOptions.isOptionSupported(name)) {
-            return extendedOptions.getOption(fd, name);
+            boolean isIPv6 = (family == StandardProtocolFamily.INET6);
+            return extendedOptions.getOption(fd, name, isIPv6);
         }
 
         // only simple values supported by this method

src/jdk.net/linux/classes/jdk/net/LinuxSocketOptions.java

@@ -108,13 +108,13 @@ class LinuxSocketOptions extends PlatformSocketOptions {
     }
 
     @Override
-    void setIpDontFragment(int fd, final boolean value) throws SocketException {
+    void setIpDontFragment(int fd, final boolean value, boolean isIPv6) throws SocketException {
-        setIpDontFragment0(fd, value);
+        setIpDontFragment0(fd, value, isIPv6);
     }
 
     @Override
-    boolean getIpDontFragment(int fd) throws SocketException {
+    boolean getIpDontFragment(int fd, boolean isIPv6) throws SocketException {
-        return getIpDontFragment0(fd);
+        return getIpDontFragment0(fd, isIPv6);
     }
 
     @Override
@@ -130,11 +130,11 @@ class LinuxSocketOptions extends PlatformSocketOptions {
     private static native void setTcpkeepAliveProbes0(int fd, int value) throws SocketException;
     private static native void setTcpKeepAliveTime0(int fd, int value) throws SocketException;
     private static native void setTcpKeepAliveIntvl0(int fd, int value) throws SocketException;
-    private static native void setIpDontFragment0(int fd, boolean value) throws SocketException;
+    private static native void setIpDontFragment0(int fd, boolean value, boolean isIPv6) throws SocketException;
     private static native int getTcpkeepAliveProbes0(int fd) throws SocketException;
     private static native int getTcpKeepAliveTime0(int fd) throws SocketException;
     private static native int getTcpKeepAliveIntvl0(int fd) throws SocketException;
-    private static native boolean getIpDontFragment0(int fd) throws SocketException;
+    private static native boolean getIpDontFragment0(int fd, boolean isIPv6) throws SocketException;
     private static native void setQuickAck0(int fd, boolean on) throws SocketException;
     private static native boolean getQuickAck0(int fd) throws SocketException;
     private static native long getSoPeerCred0(int fd) throws SocketException;

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

@@ -244,34 +244,18 @@ JNIEXPORT jint JNICALL Java_jdk_net_LinuxSocketOptions_getIncomingNapiId0
     return optval;
 }
 
-static int socketFamily(jint fd) {
-    struct sockaddr_storage st;
-    struct sockaddr *sa = (struct sockaddr *)&st;
-    socklen_t sa_len = sizeof(st);
-
-    if (getsockname(fd, sa, &sa_len) == 0) {
-        return sa->sa_family;
-    }
-    return -1;
-}
-
 /*
  * Class:     jdk_net_LinuxSocketOptions
  * Method:    setIpDontFragment0
- * Signature: (IZ)V
+ * Signature: (IZZ)V
  */
 JNIEXPORT void JNICALL Java_jdk_net_LinuxSocketOptions_setIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd, jboolean optval) {
+(JNIEnv *env, jobject unused, jint fd, jboolean optval, jboolean isIPv6) {
     jint rv, optsetting;
-    jint family = socketFamily(fd);
-    if (family == -1) {
-        handleError(env, family, "get socket family failed");
-        return;
-    }
 
     optsetting = optval ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT;
 
-    if (family == AF_INET) {
+    if (!isIPv6) {
         rv = setsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER, &optsetting, sizeof (optsetting));
     } else {
         rv = setsockopt(fd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, &optsetting, sizeof (optsetting));
@@ -282,18 +266,13 @@ JNIEXPORT void JNICALL Java_jdk_net_LinuxSocketOptions_setIpDontFragment0
 /*
  * Class:     jdk_net_LinuxSocketOptions
  * Method:    getIpDontFragment0
- * Signature: (I)Z;
+ * Signature: (IZ)Z;
  */
 JNIEXPORT jboolean JNICALL Java_jdk_net_LinuxSocketOptions_getIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd) {
+(JNIEnv *env, jobject unused, jint fd, jboolean isIPv6) {
     jint optlevel, optname, optval, rv;
-    jint family = socketFamily(fd);
-    if (family == -1) {
-        handleError(env, family, "get socket family failed");
-        return JNI_FALSE;
-    }
 
-    if (family == AF_INET) {
+    if (!isIPv6) {
         optlevel = IPPROTO_IP;
         optname = IP_MTU_DISCOVER;
     } else {

src/jdk.net/macosx/classes/jdk/net/MacOSXSocketOptions.java

@@ -84,13 +84,13 @@ class MacOSXSocketOptions extends PlatformSocketOptions {
     }
 
     @Override
-    void setIpDontFragment(int fd, final boolean value) throws SocketException {
+    void setIpDontFragment(int fd, final boolean value, boolean isIPv6) throws SocketException {
-        setIpDontFragment0(fd, value);
+        setIpDontFragment0(fd, value, isIPv6);
     }
 
     @Override
-    boolean getIpDontFragment(int fd) throws SocketException {
+    boolean getIpDontFragment(int fd, boolean isIPv6) throws SocketException {
-        return getIpDontFragment0(fd);
+        return getIpDontFragment0(fd, isIPv6);
     }
 
     @Override
@@ -106,11 +106,11 @@ class MacOSXSocketOptions extends PlatformSocketOptions {
     private static native void setTcpkeepAliveProbes0(int fd, int value) throws SocketException;
     private static native void setTcpKeepAliveTime0(int fd, int value) throws SocketException;
     private static native void setTcpKeepAliveIntvl0(int fd, int value) throws SocketException;
-    private static native void setIpDontFragment0(int fd, boolean value) throws SocketException;
+    private static native void setIpDontFragment0(int fd, boolean value, boolean isIPv6) throws SocketException;
     private static native int getTcpkeepAliveProbes0(int fd) throws SocketException;
     private static native int getTcpKeepAliveTime0(int fd) throws SocketException;
     private static native int getTcpKeepAliveIntvl0(int fd) throws SocketException;
-    private static native boolean getIpDontFragment0(int fd) throws SocketException;
+    private static native boolean getIpDontFragment0(int fd, boolean isIPv6) throws SocketException;
     private static native long getSoPeerCred0(int fd) throws SocketException;
     private static native boolean keepAliveOptionsSupported0();
     private static native boolean ipDontFragmentSupported0();

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

@@ -178,17 +178,6 @@ JNIEXPORT jint JNICALL Java_jdk_net_MacOSXSocketOptions_getTcpKeepAliveIntvl0
     return optval;
 }
 
-static int socketFamily(jint fd) {
-    struct sockaddr_storage st;
-    struct sockaddr* sa = (struct sockaddr *)&st;
-    socklen_t sa_len = sizeof(st);
-
-    if (getsockname(fd, sa, &sa_len) == 0) {
-        return sa->sa_family;
-    }
-    return -1;
-}
-
 /*
  * Class:     jdk_net_MacOSXSocketOptions
  * Method:    ipDontFragmentSupported0
@@ -198,42 +187,37 @@ JNIEXPORT jboolean JNICALL Java_jdk_net_MacOSXSocketOptions_ipDontFragmentSuppor
 (JNIEnv *env, jobject unused) {
     jint rv, fd, value;
     fd = socket(AF_INET, SOCK_DGRAM, 0);
-    if (fd == -1)
+    if (fd != -1) {
-        return JNI_FALSE;
         value = 1;
         rv = setsockopt(fd, IPPROTO_IP, IP_DONTFRAG, &value, sizeof(value));
         close(fd);
         if (rv == -1) {
             return JNI_FALSE;
         }
+    }
     fd = socket(AF_INET6, SOCK_DGRAM, 0);
-    if (fd == -1)
+    if (fd != -1) {
-        return JNI_FALSE;
         value = 1;
         rv = setsockopt(fd, IPPROTO_IPV6, IPV6_DONTFRAG, &value, sizeof(value));
         close(fd);
         if (rv == -1) {
             return JNI_FALSE;
         }
+    }
     return JNI_TRUE;
 }
 
 /*
  * Class:     jdk_net_MacOSXSocketOptions
  * Method:    setIpDontFragment0
- * Signature: (IZ)V
+ * Signature: (IZZ)V
  */
 JNIEXPORT void JNICALL Java_jdk_net_MacOSXSocketOptions_setIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd, jboolean optval) {
+(JNIEnv *env, jobject unused, jint fd, jboolean optval, jboolean isIPv6) {
     jint rv;
-    jint family = socketFamily(fd);
     jint value = optval ? 1 : 0;
 
-    if (family == -1) {
+    if (!isIPv6) {
-        handleError(env, family, "get socket family failed");
-        return;
-    }
-    if (family == AF_INET) {
         rv = setsockopt(fd, IPPROTO_IP, IP_DONTFRAG, &value, sizeof(value));
     } else {
         rv = setsockopt(fd, IPPROTO_IPV6, IPV6_DONTFRAG, &value, sizeof(value));
@@ -244,18 +228,13 @@ JNIEXPORT void JNICALL Java_jdk_net_MacOSXSocketOptions_setIpDontFragment0
 /*
  * Class:     jdk_net_MacOSXSocketOptions
  * Method:    getIpDontFragment0
- * Signature: (I)Z;
+ * Signature: (IZ)Z;
  */
 JNIEXPORT jboolean JNICALL Java_jdk_net_MacOSXSocketOptions_getIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd) {
+(JNIEnv *env, jobject unused, jint fd, jboolean isIPv6) {
     jint optval, rv;
     socklen_t sz = sizeof (optval);
-    jint family = socketFamily(fd);
+    if (!isIPv6) {
-    if (family == -1) {
-        handleError(env, family, "get socket family failed");
-        return 0;
-    }
-    if (family == AF_INET) {
         rv = getsockopt(fd, IPPROTO_IP, IP_DONTFRAG, &optval, &sz);
     } else {
         rv = getsockopt(fd, IPPROTO_IPV6, IPV6_DONTFRAG, &optval, &sz);

src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java

@@ -28,6 +28,7 @@ package jdk.net;
 import java.io.FileDescriptor;
 import java.net.SocketException;
 import java.net.SocketOption;
+import java.net.StandardProtocolFamily;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.Collections;
@@ -209,6 +210,9 @@ public final class ExtendedSocketOptions {
      * sizes to the {@link java.net.NetworkInterface#getMTU() local MTU}. Depending
      * on the implementation and the network interface, packets larger than the MTU
      * may be sent or dropped silently or dropped with an exception thrown.
+     * For {@link StandardProtocolFamily#INET6 IPv6} sockets it is
+     * system dependent whether the option also applies to datagrams
+     * sent to IPv4 addresses.
      *
      * @apiNote
      * For IPv4 this option sets the DF (Do not Fragment) flag in the IP packet
@@ -263,10 +267,9 @@ public final class ExtendedSocketOptions {
                 new sun.net.ext.ExtendedSocketOptions(extendedOptions) {
 
             @Override
-            @SuppressWarnings("removal")
             public void setOption(FileDescriptor fd,
                                   SocketOption<?> option,
-                                  Object value)
+                                  Object value, boolean isIPv6)
                 throws SocketException
             {
                 if (fd == null || !fd.valid())
@@ -277,7 +280,7 @@ public final class ExtendedSocketOptions {
                 } else if (option == TCP_KEEPCOUNT) {
                     setTcpkeepAliveProbes(fd, (Integer) value);
                 } else if (option == IP_DONTFRAGMENT) {
-                    setIpDontFragment(fd, (Boolean) value);
+                    setIpDontFragment(fd, (Boolean) value, isIPv6);
                 } else if (option == TCP_KEEPIDLE) {
                     setTcpKeepAliveTime(fd, (Integer) value);
                 } else if (option == TCP_KEEPINTERVAL) {
@@ -295,9 +298,8 @@ public final class ExtendedSocketOptions {
             }
 
             @Override
-            @SuppressWarnings("removal")
             public Object getOption(FileDescriptor fd,
-                                    SocketOption<?> option)
+                                    SocketOption<?> option, boolean isIPv6)
                 throws SocketException
             {
                 if (fd == null || !fd.valid())
@@ -308,7 +310,7 @@ public final class ExtendedSocketOptions {
                 } else if (option == TCP_KEEPCOUNT) {
                     return getTcpkeepAliveProbes(fd);
                 } else if (option == IP_DONTFRAGMENT) {
-                    return getIpDontFragment(fd);
+                    return getIpDontFragment(fd, isIPv6);
                 } else if (option == TCP_KEEPIDLE) {
                     return getTcpKeepAliveTime(fd);
                 } else if (option == TCP_KEEPINTERVAL) {
@@ -352,9 +354,9 @@ public final class ExtendedSocketOptions {
         platformSocketOptions.setTcpKeepAliveTime(fdAccess.get(fd), value);
     }
 
-    private static void setIpDontFragment(FileDescriptor fd, boolean value)
+    private static void setIpDontFragment(FileDescriptor fd, boolean value, boolean isIPv6)
             throws SocketException {
-        platformSocketOptions.setIpDontFragment(fdAccess.get(fd), value);
+        platformSocketOptions.setIpDontFragment(fdAccess.get(fd), value, isIPv6);
     }
 
     private static void setTcpKeepAliveIntvl(FileDescriptor fd, int value)
@@ -366,8 +368,8 @@ public final class ExtendedSocketOptions {
         return platformSocketOptions.getTcpkeepAliveProbes(fdAccess.get(fd));
     }
 
-    private static boolean getIpDontFragment(FileDescriptor fd) throws SocketException {
+    private static boolean getIpDontFragment(FileDescriptor fd, boolean isIPv6) throws SocketException {
-        return platformSocketOptions.getIpDontFragment(fdAccess.get(fd));
+        return platformSocketOptions.getIpDontFragment(fdAccess.get(fd), isIPv6);
     }
 
     private static int getTcpKeepAliveTime(FileDescriptor fd) throws SocketException {
@@ -462,11 +464,11 @@ public final class ExtendedSocketOptions {
             throw new UnsupportedOperationException("unsupported TCP_KEEPINTVL option");
         }
 
-        void setIpDontFragment(int fd, final boolean value) throws SocketException {
+        void setIpDontFragment(int fd, final boolean value, boolean isIPv6) throws SocketException {
             throw new UnsupportedOperationException("unsupported IP_DONTFRAGMENT option");
         }
 
-        boolean getIpDontFragment(int fd) throws SocketException {
+        boolean getIpDontFragment(int fd, boolean isIPv6) throws SocketException {
             throw new UnsupportedOperationException("unsupported IP_DONTFRAGMENT option");
         }
 

src/jdk.net/windows/classes/jdk/net/WindowsSocketOptions.java

@@ -42,17 +42,17 @@ class WindowsSocketOptions extends PlatformSocketOptions {
     }
 
     @Override
-    void setIpDontFragment(int fd, final boolean value) throws SocketException {
+    void setIpDontFragment(int fd, final boolean value, boolean isIPv6) throws SocketException {
-        setIpDontFragment0(fd, value);
+        setIpDontFragment0(fd, value, isIPv6);
     }
 
     @Override
-    boolean getIpDontFragment(int fd) throws SocketException {
+    boolean getIpDontFragment(int fd, boolean isIPv6) throws SocketException {
-        return getIpDontFragment0(fd);
+        return getIpDontFragment0(fd, isIPv6);
     }
 
-    private static native void setIpDontFragment0(int fd, boolean value) throws SocketException;
+    private static native void setIpDontFragment0(int fd, boolean value, boolean isIPv6) throws SocketException;
-    private static native boolean getIpDontFragment0(int fd) throws SocketException;
+    private static native boolean getIpDontFragment0(int fd, boolean isIPv6) throws SocketException;
 
     static {
         if (System.getSecurityManager() == null) {

src/jdk.net/windows/native/libextnet/WindowsSocketOptions.c

@@ -43,32 +43,16 @@ static void handleError(JNIEnv *env, jint rv, const char *errmsg) {
     }
 }
 
-static int socketFamily(jint fd) {
-    WSAPROTOCOL_INFO info;
-    socklen_t sa_len = sizeof(info);
-
-    if (getsockopt(fd, SOL_SOCKET, SO_PROTOCOL_INFO, (char *)&info, &sa_len) == 0) {
-        return info.iAddressFamily;
-    }
-    return -1;
-}
-
 /*
  * Class:     jdk_net_WindowsSocketOptions
  * Method:    setIpDontFragment0
- * Signature: (IZ)V
+ * Signature: (IZZ)V
  */
 JNIEXPORT void JNICALL Java_jdk_net_WindowsSocketOptions_setIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd, jboolean optval) {
+(JNIEnv *env, jobject unused, jint fd, jboolean optval, jboolean isIPv6) {
     int rv, opt;
-    jint family = socketFamily(fd);
-    if (family == -1) {
-        handleError(env, family, "get socket family failed");
-        return;
-    }
 
-
+    if (!isIPv6) {
-    if (family == AF_INET) {
         opt = optval ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT;
         rv = setsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER, (char *)&opt, sizeof(int));
         if (rv == SOCKET_ERROR && WSAGetLastError() == WSAENOPROTOOPT) {
@@ -81,7 +65,7 @@ JNIEXPORT void JNICALL Java_jdk_net_WindowsSocketOptions_setIpDontFragment0
         if (rv == SOCKET_ERROR && WSAGetLastError() == WSAENOPROTOOPT) {
             /* IPV6_MTU_DISCOVER not supported on W 2016 and older, can use old option */
             opt = optval;
-            rv = setsockopt(fd, IPPROTO_IP, IP_DONTFRAGMENT, (char *)&opt, sizeof(int));
+            rv = setsockopt(fd, IPPROTO_IPV6, IPV6_DONTFRAG, (char *)&opt, sizeof(int));
         }
     }
     handleError(env, rv, "set option IP_DONTFRAGMENT failed");
@@ -90,18 +74,13 @@ JNIEXPORT void JNICALL Java_jdk_net_WindowsSocketOptions_setIpDontFragment0
 /*
  * Class:     jdk_net_WindowsSocketOptions
  * Method:    getIpDontFragment0
- * Signature: (I)Z;
+ * Signature: (IZ)Z;
  */
 JNIEXPORT jboolean JNICALL Java_jdk_net_WindowsSocketOptions_getIpDontFragment0
-(JNIEnv *env, jobject unused, jint fd) {
+(JNIEnv *env, jobject unused, jint fd, jboolean isIPv6) {
     int optval, rv, sz = sizeof(optval);
-    jint family = socketFamily(fd);
-    if (family == -1) {
-        handleError(env, family, "get socket family failed");
-        return JNI_FALSE;
-    }
 
-    if (family == AF_INET) {
+    if (!isIPv6) {
         rv = getsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER, (char *)&optval, &sz);
         if (rv == SOCKET_ERROR && WSAGetLastError() == WSAENOPROTOOPT) {
             sz = sizeof(optval);
@@ -115,7 +94,7 @@ JNIEXPORT jboolean JNICALL Java_jdk_net_WindowsSocketOptions_getIpDontFragment0
         rv = getsockopt(fd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (char *)&optval, &sz);
         if (rv == SOCKET_ERROR && WSAGetLastError() == WSAENOPROTOOPT) {
             sz = sizeof(optval);
-            rv = getsockopt(fd, IPPROTO_IP, IP_DONTFRAGMENT, (char *)&optval, &sz);
+            rv = getsockopt(fd, IPPROTO_IPV6, IPV6_DONTFRAG, (char *)&optval, &sz);
             handleError(env, rv, "get option IP_DONTFRAGMENT failed");
             return optval;
         }