Fixes esp8266#3537

Author: cristovao-trevisan

libraries/ESP8266WiFi/src/WiFiClientSecure.cpp

@@ -605,17 +605,24 @@ extern "C" int __ax_port_read(int fd, uint8_t* buffer, size_t count)
 }
 extern "C" void ax_port_read() __attribute__ ((weak, alias("__ax_port_read")));
 
-extern "C" int __ax_port_write(int fd, uint8_t* buffer, size_t count)
-{
+uint8_t ax_port_write_retries = 0;
+extern "C" int ax_port_write(int fd, uint8_t* buffer, size_t count) {
     ClientContext* _client = SSLContext::getIOContext(fd);
     if (!_client || _client->state() != ESTABLISHED) {
         errno = EIO;
         return -1;
     }
-
-    size_t cb = _client->write(buffer, count);
+    size_t cb = _client->write((const char*) buffer, count);
     if (cb != count) {
-        errno = EAGAIN;
+        if (++ax_port_write_retries > 0x19) {
+            DEBUGV("ssl_write: Exceeded max write retries");
+            _client->close();
+            ax_port_write_retries = 0;
+            errno = ENOTCONN;
+        }
+        else errno = EAGAIN;
+    } else {
+        ax_port_write_retries = 0;
     }
     return cb;
 }