extmod/modlwip: Update to work with lwIP v2.0.

lwIP v2.0.3 has been tested with this lwip module and it works very well.

extmod/modlwip.c

@@ -38,13 +38,18 @@
 #include "lib/netutils/netutils.h"
 
 #include "lwip/init.h"
-#include "lwip/timers.h"
 #include "lwip/tcp.h"
 #include "lwip/udp.h"
 //#include "lwip/raw.h"
 #include "lwip/dns.h"
-#include "lwip/tcp_impl.h"
 #include "lwip/igmp.h"
+#if LWIP_VERSION_MAJOR < 2
+#include "lwip/timers.h"
+#include "lwip/tcp_impl.h"
+#else
+#include "lwip/timeouts.h"
+#include "lwip/priv/tcp_priv.h"
+#endif
 
 #if 0 // print debugging info
 #define DEBUG_printf DEBUG_printf
@@ -171,11 +176,16 @@ STATIC const mp_obj_type_t lwip_slip_type = {
 // Table to convert lwIP err_t codes to socket errno codes, from the lwIP
 // socket API.
 
+// lwIP 2 changed LWIP_VERSION and it can no longer be used in macros,
+// so we define our own equivalent version that can.
+#define LWIP_VERSION_MACRO (LWIP_VERSION_MAJOR << 24 | LWIP_VERSION_MINOR << 16 \
+                            | LWIP_VERSION_REVISION << 8 | LWIP_VERSION_RC)
+
 // Extension to lwIP error codes
 #define _ERR_BADF -16
 // TODO: We just know that change happened somewhere between 1.4.0 and 1.4.1,
 // investigate in more detail.
-#if LWIP_VERSION < 0x01040100
+#if LWIP_VERSION_MACRO < 0x01040100
 static const int error_lookup_table[] = {
     0,                /* ERR_OK          0      No error, everything OK. */
     MP_ENOMEM,        /* ERR_MEM        -1      Out of memory error.     */
@@ -196,7 +206,7 @@ static const int error_lookup_table[] = {
     MP_EALREADY,      /* ERR_ISCONN     -15     Already connected.       */
     MP_EBADF,         /* _ERR_BADF      -16     Closed socket (null pcb) */
 };
-#else
+#elif LWIP_VERSION_MACRO < 0x02000000
 static const int error_lookup_table[] = {
     0,                /* ERR_OK          0      No error, everything OK. */
     MP_ENOMEM,        /* ERR_MEM        -1      Out of memory error.     */
@@ -217,6 +227,30 @@ static const int error_lookup_table[] = {
     -1,               /* ERR_IF         -15     Low-level netif error    */
     MP_EBADF,         /* _ERR_BADF      -16     Closed socket (null pcb) */
 };
+#else
+// Matches lwIP 2.0.3
+#undef _ERR_BADF
+#define _ERR_BADF -17
+static const int error_lookup_table[] = {
+    0,                /* ERR_OK          0      No error, everything OK  */
+    MP_ENOMEM,        /* ERR_MEM        -1      Out of memory error      */
+    MP_ENOBUFS,       /* ERR_BUF        -2      Buffer error             */
+    MP_EWOULDBLOCK,   /* ERR_TIMEOUT    -3      Timeout                  */
+    MP_EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem          */
+    MP_EINPROGRESS,   /* ERR_INPROGRESS -5      Operation in progress    */
+    MP_EINVAL,        /* ERR_VAL        -6      Illegal value            */
+    MP_EWOULDBLOCK,   /* ERR_WOULDBLOCK -7      Operation would block    */
+    MP_EADDRINUSE,    /* ERR_USE        -8      Address in use           */
+    MP_EALREADY,      /* ERR_ALREADY    -9      Already connecting       */
+    MP_EALREADY,      /* ERR_ISCONN     -10     Conn already established */
+    MP_ENOTCONN,      /* ERR_CONN       -11     Not connected            */
+    -1,               /* ERR_IF         -12     Low-level netif error    */
+    MP_ECONNABORTED,  /* ERR_ABRT       -13     Connection aborted       */
+    MP_ECONNRESET,    /* ERR_RST        -14     Connection reset         */
+    MP_ENOTCONN,      /* ERR_CLSD       -15     Connection closed        */
+    MP_EIO,           /* ERR_ARG        -16     Illegal argument.        */
+    MP_EBADF,         /* _ERR_BADF      -17     Closed socket (null pcb) */
+};
 #endif
 
 /*******************************************************************************/
@@ -276,7 +310,12 @@ static inline void exec_user_callback(lwip_socket_obj_t *socket) {
 
 // Callback for incoming UDP packets. We simply stash the packet and the source address,
 // in case we need it for recvfrom.
-STATIC void _lwip_udp_incoming(void *arg, struct udp_pcb *upcb, struct pbuf *p, ip_addr_t *addr, u16_t port) {
+#if LWIP_VERSION_MAJOR < 2
+STATIC void _lwip_udp_incoming(void *arg, struct udp_pcb *upcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
+#else
+STATIC void _lwip_udp_incoming(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
+#endif
+{
     lwip_socket_obj_t *socket = (lwip_socket_obj_t*)arg;
 
     if (socket->incoming.pbuf != NULL) {
@@ -1287,7 +1326,12 @@ typedef struct _getaddrinfo_state_t {
 } getaddrinfo_state_t;
 
 // Callback for incoming DNS requests.
-STATIC void lwip_getaddrinfo_cb(const char *name, ip_addr_t *ipaddr, void *arg) {
+#if LWIP_VERSION_MAJOR < 2
+STATIC void lwip_getaddrinfo_cb(const char *name, ip_addr_t *ipaddr, void *arg)
+#else
+STATIC void lwip_getaddrinfo_cb(const char *name, const ip_addr_t *ipaddr, void *arg)
+#endif
+{
     getaddrinfo_state_t *state = arg;
     if (ipaddr != NULL) {
         state->status = 1;