net/SocketAddress: add method GetPort()

src/net/SocketAddress.cxx

 /*
- * Copyright (C) 2012-2015 Max Kellermann <max.kellermann@gmail.com>
+ * Copyright (C) 2012-2017 Max Kellermann <max.kellermann@gmail.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -27,12 +27,43 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "config.h"
 #include "SocketAddress.hxx"
 
 #include <string.h>
 
+#ifdef HAVE_TCP
+#ifdef WIN32
+#include <ws2tcpip.h>
+#else
+#include <netinet/in.h>
+#endif
+#endif
+
 bool
 SocketAddress::operator==(SocketAddress other) const noexcept
 {
 	return size == other.size && memcmp(address, other.address, size) == 0;
 }
+
+#ifdef HAVE_TCP
+
+unsigned
+SocketAddress::GetPort() const
+{
+	if (IsNull())
+		return 0;
+
+	switch (GetFamily()) {
+	case AF_INET:
+		return ntohs(((const struct sockaddr_in *)(const void *)address)->sin_port);
+
+	case AF_INET6:
+		return ntohs(((const struct sockaddr_in6 *)(const void *)address)->sin6_port);
+
+	default:
+		return 0;
+	}
+}
+
+#endif

src/net/SocketAddress.hxx

 /*
- * Copyright (C) 2012-2015 Max Kellermann <max.kellermann@gmail.com>
+ * Copyright (C) 2012-2017 Max Kellermann <max.kellermann@gmail.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,6 +30,7 @@
 #ifndef SOCKET_ADDRESS_HXX
 #define SOCKET_ADDRESS_HXX
 
+#include "Features.hxx"
 #include "Compiler.h"
 
 #include <cstddef>
@@ -92,6 +93,14 @@ public:
 		return GetFamily() != AF_UNSPEC;
 	}
 
+#ifdef HAVE_TCP
+	/**
+	 * Extract the port number.  Returns 0 if not applicable.
+	 */
+	gcc_pure
+	unsigned GetPort() const;
+#endif
+
 	gcc_pure
 	bool operator==(const SocketAddress other) const noexcept;