From fda874e406f47a37d5e26d402778674d777ffc2f Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky <pfalcon@users.sourceforge.net>
Date: Sat, 2 Jan 2016 23:56:27 +0200
Subject: [PATCH] extmod/modlwip: Support non-blocking recv().

---
 extmod/modlwip.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/extmod/modlwip.c b/extmod/modlwip.c
index 76b605ee8b..7fe1416206 100644
--- a/extmod/modlwip.c
+++ b/extmod/modlwip.c
@@ -385,6 +385,13 @@ STATIC mp_uint_t lwip_tcp_send(lwip_socket_obj_t *socket, const byte *buf, mp_ui
 // Helper function for recv/recvfrom to handle TCP packets
 STATIC mp_uint_t lwip_tcp_receive(lwip_socket_obj_t *socket, byte *buf, mp_uint_t len, int *_errno) {
     if (socket->incoming.pbuf == NULL) {
+
+        // Non-blocking socket
+        if (socket->timeout == 0) {
+            *_errno = EAGAIN;
+            return -1;
+        }
+
         mp_uint_t start = mp_hal_ticks_ms();
         while (socket->state == STATE_CONNECTED && socket->incoming.pbuf == NULL) {
             if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {