Note: besides the esp-netif component, this commit also disables
net_sockets.c from mbedtls, which is one of the base components and uses BSD API (not specifically lwIP). This might be refactored to use CONFIG_SUPPORT_BSD_API instead of CONFIG_ESP_NETIF_TCPIP_LWIP
in the future.
It also disables smartconfig_ack.c and wifi_init.c from esp_wifi
component for referencing some lwIP config options (smartconfig_ack.c changes might be also
updated to check CONFIG_SUPPORT_BSD_API)
Merges https://github.com/espressif/esp-idf/pull/5856
Basically, in the portability layer, it is checked if the socket is
NON-block, and if not, then even the EAGAIN and EWOULDBLOCK errors are
diverted to a RECV error. This causes a problem for sockets with
receive timeouts set. When such a timeout is set, the condition for
NON_BLOCK isn't met and hence a hard error is returned.
Searching for EAGAIN and EWOULDBLOCK in lwip returns only 3 results
(accept, recvfrom, close) and all of them look to be genuine cases for
EWOULDBLOCK. So removing this check to make receive timeout with TLS
work.
As per upgrade notes of lwIP v2.1.0:
socket API: according to the standard, SO_ERROR now only returns asynchronous errors.
All other/normal/synchronous errors are (and always were) available via 'errno'.
LWIP_SOCKET_SET_ERRNO has been removed - 'errno' is always set - and required!
Refer: https://www.nongnu.org/lwip/2_1_x/upgrading.html
Fixes https://github.com/espressif/esp-azure/issues/51
Angus Gratton