Separate interface from stack in NSAPI

This patch consists of:
-Add NetworkInterface to wrap objects bound to a stack and update
    socket code to handle this in addition to NetworkStacks
-Update MeshInterface to inherit from NetworkInterface
-Update NanostackInterface so it only inherits from NetworkStack
-Add MeshInterfaceNanostack and update LoWPANNDInterface and
    ThreadInterface to inherit from this

EthInterface.h

@@ -1,4 +1,4 @@
-/* EthernetInterface
+/* EthInterface
  * Copyright (c) 2015 ARM Limited
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,16 +14,16 @@
  * limitations under the License.
  */
 
-#ifndef ETHERNET_INTERFACE_H
-#define ETHERNET_INTERFACE_H
+#ifndef ETH_INTERFACE_H
+#define ETH_INTERFACE_H
 
-#include "NetworkStack.h"
+#include "NetworkInterface.h"
 
-/** EthernetInterface class
+/** EthInterface class
  *
  *  Common interface that is shared between ethernet hardware.
  */
-class EthernetInterface
+class EthInterface : public NetworkInterface
 {
 public:
     /** Start the interface

MeshInterface.h

@@ -17,13 +17,13 @@
 #ifndef MESH_INTERFACE_H
 #define MESH_INTERFACE_H
 
-#include "NetworkStack.h"
+#include "NetworkInterface.h"
 
 /** MeshInterface class
  *
  *  Common interface that is shared between mesh hardware
  */
-class MeshInterface
+class MeshInterface : public NetworkInterface
 {
 public:
     /** Start the interface

NetworkInterface.h

@@ -0,0 +1,41 @@
+/* NetworkStack
+ * Copyright (c) 2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef NETWORK_INTERFACE_H
+#define NETWORK_INTERFACE_H
+
+#include "mbed.h"
+#include "SocketAddress.h"
+
+class NetworkInterface {
+public:
+    virtual ~NetworkInterface() {};
+    NetworkInterface() {}
+
+    /** Get the internally stored IP address
+    /return     IP address of the interface or null if not yet connected
+    */
+    virtual const char *get_ip_address() = 0;
+protected:
+    friend class Socket;
+    friend class UDPSocket;
+    friend class TCPSocket;
+    friend class TCPServer;
+    friend class SocketAddress;
+    virtual NetworkStack * get_stack(void) = 0;
+};
+
+#endif

NetworkStack.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef NETWORK_INTERFACE_H
-#define NETWORK_INTERFACE_H
+#ifndef NETWORK_STACK_H
+#define NETWORK_STACK_H
 
 #include "mbed.h"
 #include "SocketAddress.h"

SocketAddress.cpp

@@ -15,6 +15,7 @@
  */
 
 #include "SocketAddress.h"
+#include "NetworkInterface.h"
 #include "NetworkStack.h"
 #include <string.h>
 #include "mbed.h"
@@ -144,28 +145,12 @@ static void ipv6_to_address(char *addr, const uint8_t *bytes)
 
 SocketAddress::SocketAddress(NetworkStack *iface, const char *host, uint16_t port)
 {
-    memset(&_ip_address, 0, sizeof _ip_address);
+    _SocketAddress(iface, host, port);
+}
 
-    // Check for valid IP addresses
-    if (host && ipv4_is_valid(host)) {
-        _ip_version = NSAPI_IPv4;
-        ipv4_from_address(_ip_bytes, host);
-        set_port(port);
-    } else if (host && ipv6_is_valid(host)) {
-        _ip_version = NSAPI_IPv6;
-        ipv6_from_address(_ip_bytes, host);
-        set_port(port);
-    } else {
-        // DNS lookup
-        int err = iface->gethostbyname(this, host);
-        if (!err) {
-            set_port(port);
-        } else {
-            _ip_version = NSAPI_IPv4;
-            memset(_ip_bytes, 0, NSAPI_IPv4_BYTES);
-            set_port(0);
-        }
-    }
+SocketAddress::SocketAddress(NetworkInterface *iface, const char *host, uint16_t port)
+{
+    _SocketAddress(iface->get_stack(), host, port);
 }
 
 SocketAddress::SocketAddress(const char *addr, uint16_t port)
@@ -273,3 +258,29 @@ SocketAddress::operator bool() const
 
     return false;
 }
+
+void SocketAddress::_SocketAddress(NetworkStack *iface, const char *host, uint16_t port)
+{
+    memset(&_ip_address, 0, sizeof _ip_address);
+
+    // Check for valid IP addresses
+    if (host && ipv4_is_valid(host)) {
+        _ip_version = NSAPI_IPv4;
+        ipv4_from_address(_ip_bytes, host);
+        set_port(port);
+    } else if (host && ipv6_is_valid(host)) {
+        _ip_version = NSAPI_IPv6;
+        ipv6_from_address(_ip_bytes, host);
+        set_port(port);
+    } else {
+        // DNS lookup
+        int err = iface->gethostbyname(this, host);
+        if (!err) {
+            set_port(port);
+        } else {
+            _ip_version = NSAPI_IPv4;
+            memset(_ip_bytes, 0, NSAPI_IPv4_BYTES);
+            set_port(0);
+        }
+    }
+}

SocketAddress.h

@@ -65,6 +65,7 @@ enum nsapi_version_t {
 
 // Predeclared classes
 class NetworkStack;
+class NetworkInterface;
 
 
 /** SocketAddress class
@@ -86,6 +87,19 @@ public:
      */
     SocketAddress(NetworkStack *iface, const char *host, uint16_t port = 0);
 
+    /** Create a SocketAddress from a hostname and port
+     *
+     *  The hostname may be either a domain name or an IP address. If the
+     *  hostname is an IP address, no network transactions will be performed.
+     *
+     *  On failure, the IP address and port will be set to zero
+     *
+     *  @param iface    Network interface to use for DNS resolution
+     *  @param host     Hostname to resolve
+     *  @param port     Optional 16-bit port
+     */
+    SocketAddress(NetworkInterface *iface, const char *host, uint16_t port = 0);
+
     /** Create a SocketAddress from an IP address and port
      *
      *  @param host     Null-terminated representation of the IP address
@@ -157,6 +171,7 @@ public:
     operator bool() const;
 
 private:
+    void _SocketAddress(NetworkStack *iface, const char *host, uint16_t port);
     char _ip_address[NSAPI_IP_SIZE];
     uint8_t _ip_bytes[NSAPI_IP_BYTES];
     nsapi_version_t _ip_version;

TCPServer.cpp

@@ -28,6 +28,12 @@ TCPServer::TCPServer(NetworkStack *iface)
     open(iface);
 }
 
+TCPServer::TCPServer(NetworkInterface *iface)
+    : _pending(0), _accept_sem(0)
+{
+    open(iface->get_stack());
+}
+
 TCPServer::~TCPServer()
 {
     close();
@@ -38,6 +44,11 @@ int TCPServer::open(NetworkStack *iface)
     return Socket::open(iface, NSAPI_TCP);
 }
 
+int TCPServer::open(NetworkInterface *iface)
+{
+    return TCPServer::open(iface->get_stack());
+}
+
 int TCPServer::listen(int backlog)
 {
     _lock.lock();

TCPServer.h

@@ -19,6 +19,7 @@
 
 #include "Socket.h"
 #include "TCPSocket.h"
+#include "NetworkInterface.h"
 #include "NetworkStack.h"
 #include "Semaphore.h"
 
@@ -46,6 +47,15 @@ public:
      */
     TCPServer(NetworkStack *iface);
 
+    /** Create a socket on a network interface
+     *
+     *  Creates and opens a socket on the network stack of the given
+     *  network interface.
+     *
+     *  @param iface    Network interface as target for socket
+     */
+    TCPServer(NetworkInterface *iface);
+
     /** Opens a socket
      *
      *  Creates a network socket on the specified network stack.
@@ -56,6 +66,17 @@ public:
      */
     virtual int open(NetworkStack *iface);
     
+    /** Opens a socket
+     *
+     *  Creates a network socket on the network stack of the given
+     *  network interface. Not needed if stack is passed to the
+     *  socket's constructor.
+     *
+     *  @param iface    Network interface as target for socket
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int open(NetworkInterface *iface);
+
     /** Listen for connections on a TCP socket
      *
      *  Marks the socket as a passive socket that can be used to accept

TCPSocket.cpp

@@ -29,6 +29,13 @@ TCPSocket::TCPSocket(NetworkStack *iface)
     open(iface);
 }
 
+TCPSocket::TCPSocket(NetworkInterface *iface)
+    : _pending(0), _read_sem(0), _write_sem(0)
+{
+    // TCPSocket::open is thread safe
+    open(iface->get_stack());
+}
+
 TCPSocket::~TCPSocket()
 {
     close();
@@ -40,6 +47,12 @@ int TCPSocket::open(NetworkStack *iface)
     return Socket::open(iface, NSAPI_TCP);
 }
 
+int TCPSocket::open(NetworkInterface *iface)
+{
+    // Socket::open is thread safe
+    return TCPSocket::open(iface->get_stack());
+}
+
 int TCPSocket::connect(const SocketAddress &addr)
 {
     _lock.lock();

TCPSocket.h

@@ -18,6 +18,7 @@
 #define TCPSOCKET_H
 
 #include "Socket.h"
+#include "NetworkInterface.h"
 #include "NetworkStack.h"
 #include "Semaphore.h"
 
@@ -45,6 +46,15 @@ public:
      */
     TCPSocket(NetworkStack *iface);
 
+    /** Create a socket on a network interface
+     *
+     *  Creates and opens a socket on the network stack of the given
+     *  network interface.
+     *
+     *  @param iface    Network interface as target for socket
+     */
+    TCPSocket(NetworkInterface *iface);
+
     /** Opens a socket
      *
      *  Creates a network socket on the specified network stack.
@@ -55,6 +65,17 @@ public:
      */
     virtual int open(NetworkStack *iface);
 
+    /** Opens a socket
+     *
+     *  Creates a network socket on the network stack of the given
+     *  network interface. Not needed if stack is passed to the
+     *  socket's constructor.
+     *
+     *  @param iface    Network interface as target for socket
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int open(NetworkInterface *iface);
+
     /** Connects TCP socket to a remote host
      *
      *  Initiates a connection to a remote server specified by either

UDPSocket.cpp

@@ -28,6 +28,12 @@ UDPSocket::UDPSocket(NetworkStack *iface)
     open(iface);
 }
 
+UDPSocket::UDPSocket(NetworkInterface *iface)
+    : _pending(0), _read_sem(0), _write_sem(0)
+{
+    open(iface->get_stack());
+}
+
 UDPSocket::~UDPSocket()
 {
     close();
@@ -38,6 +44,11 @@ int UDPSocket::open(NetworkStack *iface)
     return Socket::open(iface, NSAPI_UDP);
 }
 
+int UDPSocket::open(NetworkInterface *iface)
+{
+    return UDPSocket::open(iface->get_stack());
+}
+
 int UDPSocket::sendto(const char *host, uint16_t port, const void *data, unsigned size)
 {
     SocketAddress addr(_iface, host, port);

UDPSocket.h

@@ -18,6 +18,7 @@
 #define UDPSOCKET_H
 
 #include "Socket.h"
+#include "NetworkInterface.h"
 #include "NetworkStack.h"
 #include "Semaphore.h"
 
@@ -45,6 +46,15 @@ public:
      */
     UDPSocket(NetworkStack *iface);
 
+    /** Create a socket on a network interface
+     *
+     *  Creates and opens a socket on the network stack of the given
+     *  network interface.
+     *
+     *  @param iface    Network interface as target for socket
+     */
+    UDPSocket(NetworkInterface *iface);
+
     /** Opens a socket
      *
      *  Creates a network socket on the specified network stack.
@@ -55,6 +65,17 @@ public:
      */
     virtual int open(NetworkStack *iface);
 
+    /** Opens a socket
+     *
+     *  Creates a network socket on the network stack of the given
+     *  network interface. Not needed if stack is passed to the
+     *  socket's constructor.
+     *
+     *  @param iface    Network interface as target for socket
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int open(NetworkInterface *iface);
+
     /** Send a packet over a UDP socket
      *
      *  Sends data to the specified address specified by either a domain name

WiFiInterface.h

@@ -17,7 +17,7 @@
 #ifndef WIFI_INTERFACE_H
 #define WIFI_INTERFACE_H
 
-#include "NetworkStack.h"
+#include "NetworkInterface.h"
 
 /** Enum of WiFi encryption types
  *
@@ -37,7 +37,7 @@ enum nsapi_security_t {
  *
  *  Common interface that is shared between WiFi devices
  */
-class WiFiInterface
+class WiFiInterface: public NetworkInterface
 {
 public:
     /** Start the interface