Add in6addr_any and in6addr_loopback symbols.

Change-Id: I3a90fa448b6bd43321672ba74b84a4e9e8a67738
diff --git a/libc/bionic/netinet_in.cpp b/libc/bionic/netinet_in.cpp
new file mode 100644
index 0000000..dfa5d8d
--- /dev/null
+++ b/libc/bionic/netinet_in.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <netinet/in.h>
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <unistd.h>
+
+constexpr int START_PORT = 600;
+constexpr int END_PORT = IPPORT_RESERVED;
+constexpr int NUM_PORTS = (END_PORT - START_PORT);
+
+int bindresvport(int sd, struct sockaddr_in* sin) {
+  sockaddr_in sin0;
+  if (sin == nullptr) {
+    memset(&sin0, 0, sizeof(sin0));
+    sin = &sin0;
+    sin->sin_family = AF_INET;
+  }
+
+  if (sin->sin_family != AF_INET) {
+    errno = EPFNOSUPPORT;
+    return -1;
+  }
+
+  // TODO: thread safety!
+  static short port;
+  if (port == 0) {
+    port = START_PORT + (getpid() % NUM_PORTS);
+  }
+
+  for (size_t i = NUM_PORTS; i > 0; i--, port++) {
+    if (port == END_PORT) port = START_PORT;
+    sin->sin_port = htons(port);
+    int rc = TEMP_FAILURE_RETRY(bind(sd, reinterpret_cast<sockaddr*>(sin), sizeof(*sin)));
+    if (rc >= 0) return rc;
+  }
+  return -1;
+}
+
+const in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+const in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;