socket DF flag on UDP socket

ext/sockets/sockets.stub.php

@@ -1706,6 +1706,62 @@
  */
 const TCP_QUICKACK = UNKNOWN;
 #endif
+#if defined(IP_DONTFRAG)
+/**
+ * @var int
+ * @cvalue IP_DONTFRAG
+ */
+const IP_DONTFRAG = UNKNOWN;
+#endif
+#if defined(IP_MTU_DISCOVER)
+/**
+ * @var int
+ * @cvalue IP_MTU_DISCOVER
+ */
+const IP_MTU_DISCOVER = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_DO)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_DO
+ */
+const IP_PMTUDISC_DO = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_DONT)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_DONT
+ */
+const IP_PMTUDISC_DONT = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_WANT)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_WANT
+ */
+const IP_PMTUDISC_WANT = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_PROBE)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_PROBE
+ */
+const IP_PMTUDISC_PROBE = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_INTERFACE)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_INTERFACE
+ */
+const IP_PMTUDISC_INTERFACE = UNKNOWN;
+#endif
+#if defined(IP_PMTUDISC_OMIT)
+/**
+ * @var int
+ * @cvalue IP_PMTUDISC_OMIT
+ */
+const IP_PMTUDISC_OMIT = UNKNOWN;
+#endif
 
 /**
  * @strict-properties

ext/sockets/tests/socket_dontfragment.phpt

@@ -0,0 +1,19 @@
+--TEST--
+IP_MTU_DISCOVER test
+--EXTENSIONS--
+sockets
+--SKIPIF--
+<?php
+if (PHP_OS != 'Linux') {
+    die('skip For Linux only');
+}
+?>
+--FILE--
+<?php
+$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
+socket_bind($socket, '127.0.0.1', 5557);
+$ret = socket_set_option($socket, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DO);
+var_dump($ret);
+?>
+--EXPECT--
+bool(true)

ext/sockets/tests/socket_dontfragment_bsd.phpt

@@ -0,0 +1,19 @@
+--TEST--
+IP_DONTFRAG test
+--EXTENSIONS--
+sockets
+--SKIPIF--
+<?php
+if (PHP_OS != 'FreeBSD') {
+    die('skip For FreeBSD only');
+}
+?>
+--FILE--
+<?php
+$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
+socket_bind($socket, '127.0.0.1', 5557);
+$ret = socket_set_option($socket, IPPROTO_IP, IP_DONTFRAG, 1);
+var_dump($ret);
+?>
+--EXPECT--
+bool(true)